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Deep Underground Neutrino Experiment (DUNE) 1 Technical Proposal 2 - PDF document

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Deep Underground Neutrino Experiment (DUNE) 1 Technical Proposal 2 23 Feb 2018: First draft of the TP volumes due 3 Volume 2: The Single-Phase Far Detector 4 February 13, 2018 5 1 Contents 1 Contents i 2 List of Figures ix 3 List

  1. 4.4.1 Interfaces to APA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 1 4.4.2 Interface to DSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 2 4.4.3 Interface to PDS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 3 4.4.4 Interface to CE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 4 4.4.5 Interface to Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 5 4.5 Installation, Integration and Commissioning . . . . . . . . . . . . . . . . . . . . . . . . 21 6 4.5.1 Transport and Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 7 4.5.2 Integration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 8 4.6 Quality Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 9 4.6.1 Protection and Assembly (Local) . . . . . . . . . . . . . . . . . . . . . . . . . 21 10 4.6.2 Post-factory Installation (Remote) . . . . . . . . . . . . . . . . . . . . . . . . . 21 11 4.7 Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 12 4.8 Organization and Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 13 4.8.1 HV System Consortium Organization . . . . . . . . . . . . . . . . . . . . . . . 22 14 4.8.2 Planning Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 15 4.8.3 WBS and Responsibilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 16 4.8.4 High-level Cost and Schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 17 5 TPC Electronics 23 18 5.1 System Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 19 5.1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 20 5.1.2 Design Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 21 5.1.3 Scope and Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 22 5.2 System Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 23 5.2.1 Grounding and Shielding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 24 5.2.2 Distribution of Wire-Bias Voltages . . . . . . . . . . . . . . . . . . . . . . . . 26 25 5.2.3 Front-End Mother Board (FEMB) . . . . . . . . . . . . . . . . . . . . . . . . . 26 26 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 27 Front-End ASIC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 28 ADC ASIC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 29 COLDATA ASIC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 30 Cold Electronics Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 31 Alternative Designs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 32 5.2.4 Cold Electronics Feedthroughs and Cold Cables . . . . . . . . . . . . . . . . . . 26 33 5.2.5 Warm Interface Electronics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 34 5.2.6 External Power and Supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 35 5.3 Production and Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 36 5.3.1 ASIC Procurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 37 5.3.2 Board Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 38 5.3.3 Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 39 5.4 Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 40 5.4.1 APAs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 41 5.4.2 DAQ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 42 5.4.3 Other Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 43 5.5 Quality Assurance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 44 5.5.1 Initial Design Validation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 45 5.5.2 Integrated Test Facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 46 iii

  2. ProtoDUNE-SP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 1 Small Test TPC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 2 Additional Test Facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 3 5.6 Quality Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 4 5.6.1 Production (Local) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 5 5.6.2 Post-factory Installation (Remote) . . . . . . . . . . . . . . . . . . . . . . . . . 29 6 5.7 Installation, Integration, and Commissioning . . . . . . . . . . . . . . . . . . . . . . . 29 7 5.7.1 Installation and Integration with APAs . . . . . . . . . . . . . . . . . . . . . . 29 8 5.7.2 Cabling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 9 5.7.3 Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 10 5.8 Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 11 5.9 Organization and Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 12 5.9.1 Single-Phase TPC Electronics Consortium Organization . . . . . . . . . . . . . 29 13 5.9.2 Planning Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 14 5.9.3 WBS and Responsibilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 15 5.9.4 High-level Cost and Schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 16 6 Photon Detection System 30 17 6.1 Photon Detection System (PD) Overview . . . . . . . . . . . . . . . . . . . . . . . . . 30 18 6.1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 19 6.1.2 Design Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 20 6.1.3 Criteria for photon collection options performance evaluation . . . . . . . . . . 34 21 6.2 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 22 6.2.1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 23 6.3 PD Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 24 6.3.1 Photon Collector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 25 Dip-Coated Light Guides (4 pages) . . . . . . . . . . . . . . . . . . . . . . . . 36 26 Double-Shift Light Guides (4 pages) . . . . . . . . . . . . . . . . . . . . . . . . 36 27 ARAPUCA (4 pages) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 28 6.4 Tests of the technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 29 6.4.1 Tests performed in Brazil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 30 6.4.2 Tests performed at FERMILAB . . . . . . . . . . . . . . . . . . . . . . . . . . 40 31 6.5 ARAPUCA in protoDUNE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 32 6.6 Last Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 33 Hybrid or New Options (2 pages) . . . . . . . . . . . . . . . . . . . . . . . . . 42 34 6.6.1 New Techniques to Supplement or Enhance Light Yield . . . . . . . . . . . . . 42 35 Light Concentrators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 36 Hybrid and New Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 37 6.6.2 Photon Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 38 6.6.3 Electronics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 39 6.6.4 Quality Assurance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 40 6.7 Production and Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 41 6.7.1 Photon Collectors Production . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 42 Dip-Coated Light Guides (2 pages) . . . . . . . . . . . . . . . . . . . . . . . . 47 43 Double-Shift Light Guides (2 pages) . . . . . . . . . . . . . . . . . . . . . . . . 47 44 ARAPUCA (2 pages) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 45 6.7.2 APA Frame Mounting Structure and Module Fixing . . . . . . . . . . . . . . . 49 46 iv

  3. Cryogenic thermal contraction . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 1 PD Mount Frame Deformation under static PD load . . . . . . . . . . . . . . . 50 2 6.7.3 Photosensor Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 3 6.7.4 Assembly Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 4 Dip-Coated Light Guide Modules (2 pages) . . . . . . . . . . . . . . . . . . . . 51 5 Double-Shift Light Guide Modules (2 pages) . . . . . . . . . . . . . . . . . . . 51 6 ARAPUCA Modules (2 pages) . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 7 6.7.5 Electronics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 8 6.7.6 QA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 9 6.8 System Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 10 6.8.1 Anode Plane Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 11 6.8.2 Feedthroughs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 12 6.8.3 Cold Electronics (CE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 13 6.8.4 Cathode Plane Assembly (CPA) / High Voltage System (HVS): Reflector foils 14 (light enhancement) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 15 6.8.5 DAQ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 16 6.8.6 Calibration / Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 17 6.9 Installation, Integration, and Commissioning . . . . . . . . . . . . . . . . . . . . . . . 59 18 6.9.1 Transport and Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 19 6.9.2 Integration with APA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 20 6.9.3 Installation into Cryostat / Cabling . . . . . . . . . . . . . . . . . . . . . . . . 60 21 6.9.4 Calibration and Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 22 6.10 Installation, Integration and Commissioning . . . . . . . . . . . . . . . . . . . . . . . . 61 23 6.10.1 Transport and Handling (1 page) . . . . . . . . . . . . . . . . . . . . . . . . . 61 24 6.10.2 Integration with APA (2 pages) . . . . . . . . . . . . . . . . . . . . . . . . . . 61 25 6.10.3 Installation into cryostat/cabling (1 pages) . . . . . . . . . . . . . . . . . . . . 61 26 6.10.4 Calibration/Monitoring (1 pages) . . . . . . . . . . . . . . . . . . . . . . . . . 61 27 6.11 Quality Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 28 6.11.1 Production and Assembly (Local) . . . . . . . . . . . . . . . . . . . . . . . . . 62 29 6.11.2 Post-factory Installation (Remote) . . . . . . . . . . . . . . . . . . . . . . . . . 62 30 6.12 Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 31 6.13 Organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 32 6.13.1 Single-Phase Photon Detection System Consortium Organization . . . . . . . . 62 33 6.13.2 Planning Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 34 6.13.3 WBS and Responsibilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 35 6.13.4 High-level Cost and Schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 36 7 Data Acquisition System 64 37 7.1 Data Acquisition System (DAQ) Overview (Georgia Karagiorgi & David Newbold) . . . 64 38 7.1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 39 7.1.2 Design Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 40 7.1.3 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 41 7.2 DAQ Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 42 7.2.1 Overview (Giles Barr) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 43 7.2.2 Local Readout & Buffering (Giles Barr & Giovanna Miotto & Brett Viren) . . . 68 44 7.2.3 Local Trigger Primitive Generation (Josh Klein & J.J. Russel & Brett Viren & 45 DP Expert?) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 46 v

  4. 7.2.4 Dataflow, Trigger and Event Builder (Giles Barr & Josh Klein & Giovanna Miotto 1 & Kurt Biery & Brett Viren) . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 2 7.2.5 Data Selection Algorithms (Josh Klein & Brett Viren) . . . . . . . . . . . . . . 73 3 7.2.6 Timing & Synchronization (David Cussans & Kostas Manolopoulos) . . . . . . . 76 4 Beam timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 5 7.2.7 Computing & Network Infrastructure (Kurt Biery & Babak Abi) . . . . . . . . . 80 6 7.2.8 Run Control & Monitoring (Giovanna Miotto & Jingbo Wang . . . . . . . . . . 80 7 7.3 Interfaces (David Cussans & Matt Graham) . . . . . . . . . . . . . . . . . . . . . . . . 80 8 7.3.1 TPC Electronics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 9 7.3.2 PD Electronics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 10 7.3.3 Offline Computing (Kurt Biery) . . . . . . . . . . . . . . . . . . . . . . . . . . 80 11 7.3.4 Slow Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 12 7.3.5 External Systems (Giles & Alec) . . . . . . . . . . . . . . . . . . . . . . . . . . 81 13 Beam Trigger: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 14 Astrophysical Triggers: . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 15 7.4 Production and Assembly (David Newbold) . . . . . . . . . . . . . . . . . . . . . . . . 81 16 7.5 Installation, Integration and Commissioning (David Newbold & Alec Habig) . . . . . . . 82 17 7.5.1 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 18 7.5.2 Integration with TPC/PD Electronics . . . . . . . . . . . . . . . . . . . . . . . 82 19 7.5.3 Commissioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 20 7.6 Safety (David Newbold & Alec Habig) . . . . . . . . . . . . . . . . . . . . . . . . . . 82 21 7.7 Organization and Management (David Newbold & Georgia Karagiorgi) . . . . . . . . . 82 22 7.7.1 DAQ Consortium Organization . . . . . . . . . . . . . . . . . . . . . . . . . . 83 23 7.7.2 Planning Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 24 7.7.3 WBS and Responsibilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 25 7.7.4 High-level Cost and Schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 26 8 Slow Controls and Cryogenics Instrumentation 84 27 8.1 Slow Controls and Cryogenics Instrumentation Overview . . . . . . . . . . . . . . . . . 84 28 8.1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 29 8.1.2 Design Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 30 8.1.3 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 31 8.2 Cryogenics Instrumentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 32 8.2.1 Fluid Dynamics Simulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 33 8.2.2 Purity Monitors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 34 8.2.3 Thermometers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 35 Static T-Gradient monitors . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 36 Dynamic T-Gradient monitors . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 37 Individual Temperature Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . 87 38 Readout system for thermometers . . . . . . . . . . . . . . . . . . . . . . . . . 88 39 8.2.4 Liquid Level Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 40 8.2.5 Gas Analyzers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 41 8.2.6 Cameras . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 42 Cryogenic Cameras (cold) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 43 Inspection Cameras (warm) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 44 Light emitting system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 45 8.2.7 Cryogenics Test Facility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 46 vi

  5. 8.2.8 Cryogenic Internal Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 1 8.2.9 Local Integration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 2 8.2.10 Quality Assurance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 3 8.3 Slow Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 4 8.3.1 Slow Controls Hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 5 Slow Controls Network Hardware . . . . . . . . . . . . . . . . . . . . . . . . . 89 6 Slow Controls Computing Hardware . . . . . . . . . . . . . . . . . . . . . . . . 90 7 Slow Controls Signal Processing Hardware . . . . . . . . . . . . . . . . . . . . 90 8 8.3.2 Slow Controls Infrastructure . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 9 8.3.3 Slow Controls Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 10 8.3.4 Slow Controls Quantities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 11 8.3.5 Local Integration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 12 8.3.6 Quality Assurance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 13 8.4 Production and Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 14 8.5 Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 15 8.5.1 Interface with External Cryogenics Systems . . . . . . . . . . . . . . . . . . . . 91 16 8.5.2 Interface with Environmental and Building Controls . . . . . . . . . . . . . . . 92 17 8.5.3 Interface with High Voltage Systems . . . . . . . . . . . . . . . . . . . . . . . 92 18 8.5.4 Interface with DAQ/Electronics . . . . . . . . . . . . . . . . . . . . . . . . . . 93 19 8.5.5 Interface with Other Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 20 8.6 Installation, Integration and Commissioning . . . . . . . . . . . . . . . . . . . . . . . . 93 21 8.6.1 Transport and Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 22 8.6.2 Integration Facility Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 23 8.6.3 Underground Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 24 8.6.4 Commissioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 25 8.7 Quality Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 26 8.8 Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 27 8.9 Organization and Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 28 8.9.1 Slow Controls and Cryogenics Instrumentation Consortium Organization . . . . . 94 29 8.9.2 Planning Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 30 8.9.3 WBS and Responsibilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 31 8.9.4 High-level Cost and Schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 32 9 Technical Coordination 95 33 9.1 Project Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 34 9.1.1 Project Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 35 9.1.2 Reviews . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 36 9.1.3 Quality Assurance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 37 9.1.4 ES&H . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 38 9.1.5 Integration and Systems Engineering . . . . . . . . . . . . . . . . . . . . . . . 95 39 Configuration Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 40 Engineering process and support . . . . . . . . . . . . . . . . . . . . . . . . . . 96 41 9.2 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 42 9.2.1 Organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 43 9.2.2 Integration and Test Facility . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 44 Baseline scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 45 Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 46 vii

  6. 9.2.3 Underground Detector Installation . . . . . . . . . . . . . . . . . . . . . . . . . 97 1 Baseline scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 2 Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 3 10 Detector Performance 98 4 10.1 ?? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 5 6 viii

  7. List of Figures 1 2.1 The field cages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2 3.1 APA diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3 3.2 APA dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 4 3.3 APA bolted joint drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 5 3.4 APA full-size mesh drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 6 3.5 APA board stack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 7 3.6 APA wire board connection to electronics . . . . . . . . . . . . . . . . . . . . . . . . . 11 8 3.7 APA side board model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 9 3.8 APA side board photo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 10 4.1 optional caption for LoF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 11 5.1 optional caption for LoF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 12 6.1 Cartoon schematic of the operation of a double-shift light guide. . . . . . . . . . . . . . 37 13 6.2 Drawing of two ARAPUCAs, each one read-out by 12 SiPMs. This design has been used 14 for the protoDUNE ARAPUCAs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 15 6.3 ARAPUCA and the schematic representation of the operating principle . . . . . . . . . 39 16 6.4 ARAPUCA test at LNLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 17 6.5 ARAPUCA array in protoDUNE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 18 6.6 X-ARAPUCA design (exploded view). . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 19 6.7 TPB-coated acrylic plates after spraying at Indiana University during fabrication of parts 20 for ProtoDUNE-SP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 21 6.8 EJ-280 light guide within darkbox for attenuation scan QA at Indiana University (pre- 22 pared for ProtoDUNE-SP). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 23 6.9 Mounting of the WLS plates to the EJ-280 bar. . . . . . . . . . . . . . . . . . . . . . 48 24 7.1 DAQ Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 25 7.2 Baseline Readout and Buffering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 26 7.3 Arrangement of Components in DUNE Timing System . . . . . . . . . . . . . . . . . . 77 27 7.4 Arrangement of components in Single Phase Timing System . . . . . . . . . . . . . . . 78 28 8.1 optional caption for LoF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 29 8.2 sensor support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 30 8.3 sensorcable support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 31 ix

  8. 1 x

  9. List of Tables 1 2.1 TPC detection components, dimensions and quantities . . . . . . . . . . . . . . . . . . 3 2 3.1 Prelim physics requirements that motivate APA design parameters . . . . . . . . . . . . 5 3 3.2 APA design parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 4 3.3 Baseline bias voltages for APA wire layers . . . . . . . . . . . . . . . . . . . . . . . . . 8 5 3.4 CuBe wire tensile strength and CTE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 6 4.1 Important requirements on the HV system design . . . . . . . . . . . . . . . . . . . . . 18 7 5.1 Important requirements on the TPC Electronics system design . . . . . . . . . . . . . . 24 8 6.1 Important requirements on the PD system design . . . . . . . . . . . . . . . . . . . . . 34 9 6.2 Shrinkage of Photon Detector Materials . . . . . . . . . . . . . . . . . . . . . . . . . . 49 10 6.3 Relative Shrinkage of PD components and APA frame, and mitigations . . . . . . . . . 50 11 7.1 Important requirements on the DAQ system design . . . . . . . . . . . . . . . . . . . . 65 12 8.1 Important requirements on the system design . . . . . . . . . . . . . . . . . . . . . . . 85 13 14 xi

  10. Todo list 1 e.g. underground locale/construction, wrapped wires, etcâĂę . . . . . . . . . . . . . . . . . . . 1 2 e.g. brief accounting of each) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 3 Mitch, I (Anne) put this in here; do with what you like. The numbers in this chapter come from 4 ProtoDUNE-SP; fix them for DUNE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 5 Include an image of the entire module, indicating its parts. . . . . . . . . . . . . . . . . . . . . 2 6 Include an image of the overall system, indicating its parts. Show how the system fits into the 7 overall detector. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 8 Anne suggests: Within this section add ref to requirements document when it’s ready, and maybe 9 list the most important half dozen in a table here). E.g., . . . . . . . . . . . . . . . . . . . 5 10 By the end of the volume, for every requirement listed in this section, there should exist an 11 explanation of how it will be satisfied. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 12 Include an image of the subsystem (frame), indicating its parts. Show how the system fits into 13 the overall system (APA). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 14 Include an image of the subsystem (boards), indicating its parts. Show how the system fits into 15 the overall system (APA). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 16 Ideas from the QA plan - topics to address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 17 It would be nice to coordinate with the interface documents; email to Jack F sent 12/20 . . . . . 14 18 Include an image of each interface in appropriate section. . . . . . . . . . . . . . . . . . . . . . 14 19 Points taken from doc 2145, dune mgmt plan . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 20 I asked Maxine about standardized org charts for each consortium. It would be nice to have these. 21 Anne . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 22 Include an image of the overall system, indicating its parts. Show how the system fits into the 23 overall detector. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 24 Anne suggests: Within this section add ref to requirements document when it’s ready, and maybe 25 list the most important half dozen in a table here). E.g., . . . . . . . . . . . . . . . . . . . 17 26 By the end of the volume, for every requirement listed in this section, there should exist an 27 explanation of how it will be satisfied. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 28 Include an image of the subsystem, indicating its parts. Show how the system fits into the overall 29 system). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 30 Include an image of each interface in appropriate section. . . . . . . . . . . . . . . . . . . . . . 20 31 Add in appropriate subsections for the pieces that HV interfaces with. These initial ones may not 32 be right. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 33 Some initial text suggested by Anne (in fact the APA section in the protodune SP TDR has a lot 34 of good descriptive text) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 35 Include an image of the overall system, indicating its parts. Show how the system fits into the 36 overall detector. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 37 xii

  11. Anne suggests: Within this section add ref to requirements document when it’s ready, and maybe 1 list the most important half dozen in a table here). E.g., . . . . . . . . . . . . . . . . . . . 23 2 By the end of the volume, for every requirement listed in this section, there should exist an 3 explanation of how it will be satisfied. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 4 Whatever the items are... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 5 Include an image of the subsystem, indicating its parts. Show how the system fits into the overall 6 system). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 7 not sure what subsections are needed: power supplies, feedthroughs? . . . . . . . . . . . . . . . 24 8 Include an image of each interface in appropriate section. . . . . . . . . . . . . . . . . . . . . . 26 9 Add in appropriate subsections for the pieces that TPC Electronics interfaces with. These initial 10 ones may not be right. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 11 Chapter editor: Wilson . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 12 (Length: TDR=10 pages, TP=3 pages) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 13 Content: Segreto . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 14 Include an image of the overall system, indicating its parts. Show how the system fits into the 15 overall detector. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 16 Include summary of simulation status? Szelc/Himmel . . . . . . . . . . . . . . . . . . . . . . . 31 17 Content: Segreto/Warner/Mualem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 18 Anne suggests: Within this section add ref to requirements document when it’s ready, and maybe 19 list the most important half dozen in a table here). E.g., . . . . . . . . . . . . . . . . . . . 33 20 By the end of the volume, for every requirement listed in this section, there should exist an 21 explanation of how it will be satisfied. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 22 Content: Segreto . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 23 Content: Segreto/Warner/Mualem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 24 Whatever the items are... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 25 (Length: TDR=50 pages, TP=20 pages) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 26 Content: Conveners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 27 Include an image of the subsystem, indicating its parts. Show how the system fits into the overall 28 system). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 29 Content: Cavanna/Whittington/Machado . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 30 Content: Toups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 31 Content: Whittington . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 32 Content: A.A.Machado (?) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 33 May not have figures integrated yet (or bibliography) - LMM . . . . . . . . . . . . . . . . . . . 38 34 Content: Cavanna/Whittington/Machado . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 35 Content: (1 page) - Cavanna . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 36 Content: (2 pages) - Zutshi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 37 Content: (3 pages) - Moreno/Franchi/Djurcic . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 38 rjw: Include comment whether there are differences between the photon collector options . . . . 46 39 Content: (1 page) - Warner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 40 (Length: TDR=40 pages, TP=8 pages) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 41 Content: Cavanna/Whittington/Machado . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 42 Content: (2 pages) - Warner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 43 Insert Dave’s PD Mounting rails in APA frame mpicture . . . . . . . . . . . . . . . . . . . . . . 49 44 Insert Dave’s PD Mounting screws mpicture . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 45 format table better? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 46 Needs better table formatting? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 47 xiii

  12. Insert Dave’s 4 deflection pictures here . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 1 Same for bars and ARAPUCAs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 2 Content: (1 page) - Zutshi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 3 Just cold boards? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 4 Content: Cavanna/Whittington/Machado . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 5 Can we have a single section that describes how the bars and/or ARAPUCA are assembled into 6 PC modules or do we need a separate subsub(!)section for each? . . . . . . . . . . . . . . 51 7 Content: (2 pages) Moreno/Franchi/Djurcic . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 8 Content: (2 pages) - Warner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 9 Content: Kemp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 10 (Length: TDR=10 pages, TP=2 pages) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 11 Include an image of each interface in appropriate section. . . . . . . . . . . . . . . . . . . . . . 52 12 Content: Kemp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 13 (Length: TDR=30 pages, TP=6 pages) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 14 Content: Warner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 15 (Length: TDR=10 pages, TP=2 pages) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 16 Content: Warner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 17 (Length: TDR=5 pages, TP=1 pages) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 18 Content: Segreto/Warner/Mualem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 19 (Length: TDR=20 pages, TP=4 pages) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 20 Content: Segreto . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 21 Content: Segreto/Warner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 22 Content: Warner/Mualem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 23 Content: Warner/Mualem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 24 2 Pages - largely generic but some highlighting of SP-specifics. . . . . . . . . . . . . . . . . . . 64 25 Describe figure here. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 26 Include: Raw data rate from WIBs, Josh’s table of data volumes for each event type and the 30 27 PB/year offline limit. Space and thermal power limits. Note, this table may be better put 28 sec:fdsp-daq-design into Section 7.2 to make this section more generic. . . . . . . . . . . . . . . . . . . . . . . 64 29 Anne suggests: Within this section add ref to requirements document when it’s ready, and maybe 30 list the most important half dozen in a table here). E.g., . . . . . . . . . . . . . . . . . . . 64 31 By the end of the volume, for every requirement listed in this section, there should exist an 32 explanation of how it will be satisfied. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 33 fig:daq-overview This section may also wish to refer to Fig. 7.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 34 Whatever the items are... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 35 16 Pages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 36 Describe how the data is received from the detector electronics, and buffered while awaiting a 37 trigger decision, together with any processing that affects stored data. The starting point 38 is data incoming from the WIBs and the end point is corresponding data sitting in memory 39 ready for event building. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 40 Below are from slides bv may show at the Jan WS. Content copied here and now as a starting 41 point. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 42 Matt: help! Each RCE consists of a .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 43 Ideas? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 44 xiv

  13. Describe the dataflow infrastructure . This should cover transport of data and trigger information, 1 infrastructure for generating local and global trigger commands (but not their algorithms, 2 that’s next), as well as what happens to the data once a trigger is generated (ie. event 3 fig:daq-readout-buffering-baseline building). Figure 7.2 may be referenced . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 4 5 Pages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 5 fig:daq-overview Include an image of each interface in appropriate section. Can maybe refer to Fig. 7.1 but it 6 currently lacks some of the interfaces. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 7 Need to receive information on beam spills (Giles) , SNEWS (Alec). . . . . . . . . . . . . . . . . 81 8 1 Page . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 9 2 Pages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 10 1 Page . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 11 2 Pages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 12 Write a better description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 13 Include an image of the overall system, indicating its parts. Show how the system fits into the 14 overall detector. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 15 Anne suggests: Within this section add ref to requirements document when it’s ready, and maybe 16 list the most important half dozen in a table here). E.g., . . . . . . . . . . . . . . . . . . . 84 17 By the end of the volume, for every requirement listed in this section, there should exist an 18 explanation of how it will be satisfied. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 19 Whatever the items are... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 20 Include an image of the subsystem, indicating its parts. Show how the system fits into the overall 21 system). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 22 provide overview and definition of required CFD, encompassing relevant WBS items for “Sim- 23 ulation studies of fluid dynamics within the cryostat” for the purity monitor system, the 24 temperature measurement system, and the level monitoring... . . . . . . . . . . . . . . . . 85 25 need this one? left out for now . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 26 Include an image of the subsystem, indicating its parts. Show how the system fits into the overall 27 system). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 28 I am completely making up how many special purpose iFix machines there should be: need input 29 from the cryo people . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 30 Is this the place for the laundry list of Things to Be Monitored? ( but which are not cryo related ) 90 31 Glenn’s talk from the parallel session @CERN is a great starting point here . . . . . . . . . . . . 90 32 need this one? not assigned . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 33 This section not needed? Not assigned; may be addressed in earlier sections. . . . . . . . . . . . 91 34 Include an image of each interface in appropriate section. . . . . . . . . . . . . . . . . . . . . . 91 35 Add in appropriate subsections for the pieces that this interfaces with. These initial ones may not 36 be right, or some interfaces may be missing. . . . . . . . . . . . . . . . . . . . . . . . . . 91 37 specify external interface of Cryo Inst. Systems with systems outside the cryostat (with LBNF), 38 detector Interface to LBNF design teams working on the design on cryogenic systems (in- 39 cluding cryogenic piping) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 40 describe interface with LBNF on environmental and building controls . . . . . . . . . . . . . . . 92 41 Describe interface with HV systems, including use of cameras for HV monitoring, and also drift 42 HV, current toroid, ground planes, and field cage pickoffs . . . . . . . . . . . . . . . . . . 92 43 Describe interface with DAQ system, including Interface with DAQ/Electronics groups for a slow 44 controls test facility at SURF, possibly as part of the DAQ test stand . . . . . . . . . . . . 93 45 structure under here is recommended . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 46 xv

  14. Chapter 1: Design Motivation 1–1 Chapter 1 1 Design Motivation 2 ch:fdsp-apa-design 1.1 Introduction to Single-Phase Far Detector in DUNE/LBNF 3 sec:fdsp-design-intro 1.2 DUNE Physics 4 sec:fdsp-design-phys 1.2.1 Goals (Oscillation Physics, Supernova Neutrinos, Proton Decay) 5 sec:fdsp-design-goals 1.2.2 Requirements 6 sec:fdsp-design-reqs 1.3 Single-Phase LArTPC for DUNE 7 sec:fdsp-design-tpc 1.4 Operational Principle 8 sec:fdsp-design-op 1.5 Implementation of Single-Phase LArTPC Design at DUNE 9 sec:fdsp-design-impl e.g. underground locale/construction, wrapped wires, etcâĂę 10 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  15. Chapter 2: Overview of the Single-Phase Detector Module Design 2–2 Chapter 2 1 Overview of the Single-Phase Detector 2 Module Design 3 ch:fdsp-ov 2.1 Model of the TPC, and coordinate definitions 4 sec:fdsp-ov-model 2.2 Primary Detector Systems 5 sec:fdsp-ov-sys e.g. brief accounting of each) 6 Mitch, I (Anne) put this in here; do with what you like. The numbers in this chapter come from ProtoDUNE-SP; fix them for DUNE 7 intro:detector The elements composing a single-phase detector module, listed in Section ?? , include the time 8 projection chamber (TPC), the cold electronics (CE), and the photon detection system (PDS). 9 The TPC components, e.g., anode planes, cathode planes and the field cage, are designed in a 10 modular way. The six APAs are arranged into two APA planes, each consisting of three side-by- 11 side APAs. Between them, a central cathode plane, composed of 18 CPA modules, splits the TPC 12 volume into two electron-drift regions, one on each side of the cathode plane. A field cage (FC) 13 completely surrounds the four open sides of the two drift regions to ensure that the electric field 14 within is uniform and unaffected by the presence of the cryostat walls and other nearby conductive 15 structures. 16 fig:fc-overview Figure 2.1 illustrates how these components fit together. 17 Include an image of the entire module, indicating its parts. 18 tab:tpc-components Table 2.1 lists the principal detection elements of the single-phase detector module along with their 19 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  16. Chapter 2: Overview of the Single-Phase Detector Module Design 2–3 Figure 2.1: A view of the TPC field cage and the central cathode plane (CPA). The APAs, which would be positioned at both open ends of the FC, are not shown. fig:fc-overview approximate dimensions and their quantities. 1 Table 2.1: TPC detection components, dimensions and quantities Approx Dimensions Quantity Detection Element APA 6 m H by 2.4 m W 3 per anode plane, 6 total CPA module 2 m H by 1.2 m W 3 per CPA column, 18 total in cathode plane Top FC module 2.4 m W by 3.6 m along drift 3 per top FC assembly, 6 total Bottom FC module 2.4 m W by 3.6 m along drift 3 per bottom FC assembly, 6 total End-wall FC module 1.5 m H by 3.6 m along drift 4 per end-wall assembly (vertical drift volume edge), 16 total PD module 2.2 m × 86 mm × 6 mm 10 per APA, 60 total tab:tpc-components 2.2.1 APAs 2 sec:fdsp-ov- 2.2.2 HV 3 sec:fdsp-ov- 2.2.3 Electronics 4 sec:fdsp-ov- 2.2.4 Photon Detector 5 sec:fdsp-ov- 2.2.5 DAQ 6 sec:fdsp-ov- 2.2.6 Instrumentation: Slow Controls and Cryogenics 7 sec:fdsp-ov-instr 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  17. Chapter 3: Anode Plane Assemblies 3–4 Chapter 3 1 Anode Plane Assemblies 2 ch:fdsp-apa 3.1 Anode Plane Assembly (APA) Overview 3 sec:fdsp-apa-ov 3.1.1 Introduction 4 sec:fdsp-apa-intro Anode Plane Assemblies (APAs) are the far detector elements utilized to sense ionization created 5 by charged particles traversing the liquid argon volume inside the single-phase TPC. The planes 6 are interleaved with Cathode Plane Assemblies (CPAs), as shown in Figure..., to establish the 7 required electric fields and form drift volumes for the charged particles. 8 Include an image of the overall system, indicating its parts. Show how the system fits into the overall detector. 9 The operating principle is illustrated in Figure... (add figure) 10 An APA consists of a rectangular framework with a fine wire mesh stretched across it, over which 11 are wrapped four layers of sense and shielding wires... ... 12 3.1.2 Design Considerations 13 sec:fdsp-apa-des-consid The APA design must enable identification of minimum-ionizing particles (MIPs). This is a func- 14 tion of several detector parameters, including: argon purity, drift distance, diffusion, wire pitch, 15 and Equivalent Noise Charge (ENC). DUNE-SP requires that MIPs originating anywhere inside 16 the active volume of the detector be reconstructed with 100% efficiency. The choice of wire pitch, 17 of ∼ 5 mm, for the wire layers on the APA, combined with key parameters for other TPC sys- 18 tems (described in their respective sections of the TDR), is expected to enable the 100% MIP 19 identification efficiency. 20 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  18. Chapter 3: Anode Plane Assemblies 3–5 DUNE-SP requires that it be possible to determine the fiducial volume (via analysis) to < 1%, 1 which in turn requires reaching a vertex resolution of ∼ 1.5 cm along each coordinate direction. 2 (The fiducial volume, among other factors, determines the number of target nucleons, which is 3 a component in cross section measurements.) The fine granularity of the APA wires enables 4 excellent precision in identifying the location of any vertices in an event, (e.g., the primary vertex 5 in a neutrino interaction or gamma conversion points in a π 0 decay), which has a direct impact on 6 reconstruction efficiency. In practice, the resolution on the drift-coordinate ( x ) of a vertex or hit 7 will be better than that on its location in the y − z plane, due to the combination of drift-velocity 8 and electronics sampling-rate... 9 The size of the APAs is chosen for fabrication purposes, compatibility with over-the-road shipping, 10 and for eventual transport to the 4850 level at SURF and installation into the membrane cryostat 11 of a detector module. Sufficient shock absorption and clearances are taken into account at each 12 stage. The dimensions are also chosen such that an integral number of electronic readout channels 13 and boards fill in the full area of the APA. The modularity of the APAs allows them to be built and 14 tested at off-site production facilities, decoupling their manufacturing time from the construction 15 of the membrane cryostat. ... 16 Anne suggests: Within this section add ref to requirements document when it’s ready, and maybe list the most important half dozen in a table here). E.g., 17 The initial physics performance requirements that drive the design of the APA are listed in Ta- 18 tab:apaphysicsrequirements ble 3.1. These are chosen to enable high-efficiency reconstruction throughout the entire active 19 volume of the LArTPC. 20 Table 3.1: Preliminary physics requirements that motivate APA design parameters. Value Requirement MIP Identification 100 % efficiency High efficiency for charge reconstruction > 90 % for > 100 MeV Vertex Resolution (x,y,z) (1.5 cm, 1.5 cm, 1.5 cm) Particle Identification Muon Momentum Resolution < 18 % for non-contained < 5 % for contained Muon Angular Resolution < 1 ◦ Stopping Hadrons Energy Resolution 1-5 % Hadron Angular Resolution < 10 ◦ Shower identification Electron efficiency > 90 % Photon mis-identification < 1 % Electron Angular Resolution < 1 ◦ Electron Energy Scale Uncertainty < 5 % tab:apaphysicsrequirements By the end of the volume, for every requirement listed in this section, there should exist an explanation of how it will be satisfied. 21 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  19. Chapter 3: Anode Plane Assemblies 3–6 3.1.3 Scope 1 sec:fdsp-apa-scope The scope of the Anode Plane Assembly (APA) system includes the continued procurement of 2 materials for, and the fabrication, testing, delivery and installation of the following systems: 3 • a framework of lightweight, rectangular stainless steel tubing; 4 • a mesh layer attached directly to both sides of the APA frame; 5 • layers of sense and shielding wires wrapped at varying angles relative to each other; 6 • stacked head electronics boards, which are wire boards for anchoring the wires at the top 7 (head) of the APA; 8 • capacitive-resistive (CR) boards that link the wire boards to the cold electronics (CE); 9 • side and foot boards along the other three edges of the APA with notches and pins to hold 10 the wires in place; 11 • modular boxes to hold the CE; 12 • comb wire supports, mounted on cross braces distributed along the length of the APA, to 13 prevent wire deflection; and 14 • pin/slot pairs on the side edges of adjacent APAs to maintain coplanarity. 15 3.2 APA Design 16 sec:fdsp-apa-design An APA is constructed from a framework of lightweight, rectangular stainless steel tubing, with 17 a fine mesh covering the rectangular area within the frame, on both sides, that defines a uniform 18 ground across the frame. Along the length of the frame and around it, over the mesh layer, layers 19 of sense and shielding wires are strung or wrapped at varying angles relative to each other, as 20 fig:tpc_apa1 illustrated in Figure 3.1. The wires are terminated on boards that anchor them and also provide 21 the connections to the cold electronics. The APAs are 2.3 m wide, 6.3 m high, and 12 cm thick. 22 tab:apaparameters The principal design parameters are listed in Table 3.2. 23 Starting from the outermost wire layer, there is first a shielding (grid) plane, followed by two 24 induction planes, and finally the collection plane. All wire layers span the entire height of the 25 fig:tpc_apa1 APA frame. The layout of the wire layers is illustrated in Figure 3.1. 26 The angle of the induction planes in the APA ( ± 35.7 ◦ ) is chosen such that each induction wire 27 only crosses a given collection wire one time, reducing the ambiguities that the reconstruction 28 must address. The design angle of the induction wires, coupled with their pitch, was also chosen 29 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  20. Chapter 3: Anode Plane Assemblies 3–7 Table 3.2: APA design parameters Value Parameter Active Height 5.984 m Active Width 2.300 m Wire Pitch (U,V) 4.669 mm Wire Pitch (X,G) 4.790 mm Wire Position Tolerance 0.5 mm Wire Plane Spacing 4.75 mm Wire Angle (w.r.t. vertical) (U,V) 35.7 ◦ Wire Angle (w.r.t. vertical) (X,G) 0 ◦ Number Wires / APA 960 (X), 960 (G), 800 (U), 800 (V) Number Electronic Channels / APA 2560 Wire Tension 5.0 N Wire Material Beryllium Copper Wire Diameter 150 µ m 7.68 µ Ω -cm @ 20 ◦ C Wire Resistivity 4.4 Ω /m @ 20 ◦ C Wire Resistance/m Frame Planarity 5 mm Photon Detector Slots 10 tab:apaparameters Figure 3.1: Sketch of a ProtoDUNE-SP APA. This shows only portions of each of the three wire layers, U (green), V (magenta), the induction layers; and X (blue), the collection layer, to accentuate their angular relationships to the frame and to each other. The induction layers are connected electrically across both sides of the APA. The grid layer (G) wires (not shown), run vertically, parallel to the X layer wires; separate sets of G and X wires are strung on the two sides of the APA. The mesh is not shown. fig:tpc_apa1 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  21. Chapter 3: Anode Plane Assemblies 3–8 such that an integer multiple of electronics boards reads out one APA. 1 The wires of the grid (shielding) layer, G, are not connected to the electronic readout; the wires 2 run parallel to the long edge of the APA frame; there are separate sets of G wires on the two sides 3 of the APA. The two planes of induction wires (U and V) wrap in a helical fashion around the 4 long edge of the APA, continuously around both sides of the APA. The collection plane wires (X) 5 run vertically, parallel to G. The ordering of the layers, from the outside in, is G-U-V-X, followed 6 by the mesh. 7 tab:bias The operating voltages of the APA layers are listed in Table 3.3. When operated at these voltages, 8 the drifting ionization follows trajectories around the grid and induction wires, ultimately termi- 9 nating on a collection plane wire; i.e., the grid and induction layers are completely transparent 10 to drifting ionization, and the collection plane is completely opaque. The grid layer is present for 11 pulse-shaping purposes, effectively shielding the first induction plane from the drifting charge and 12 removing the long leading edge from the signals on that layer; again, it is not connected to the 13 electronics readout. The mesh layer serves to shield the sense planes from pickup from the Photon 14 Detection System and from “ghost” tracks that would otherwise be visible when ionizing particles 15 have a trajectory that passes through the collection plane. 16 Table 3.3: Baseline bias voltages for APA wire layers Bias Voltage Anode Plane Grid (G) -665 V Induction (U) -370 V Induction (V) 0 V Collection (X) 820 V Mesh (M) 0 V tab:bias The wrapped style allows the APA plane to fully cover the active area of the LArTPC, minimizing 17 the amount of dead space between the APAs that would otherwise be occupied by electronics and 18 associated cabling. 19 In the current design of the DUNE-SP far detector module, a central row of APAs is flanked by 20 drift-fields, requiring sensitivity on both sides. The wrapped APAs allow the induction plane wires 21 to sense drifting ionization originating from either side of the APA. This double-sided feature is 22 not strictly necessary for the ProtoDUNE-SP arrangement, which has APAs located against the 23 cryostat walls and a drift field on one side only, but it is compatible with this setup as the grid 24 layer facing the wall effectively blocks any ionization generated outside the TPC from drifting in 25 to the wires on that side of the APA. 26 The choices of wire tension and wire placement accuracy are made to ensure proper operation of 27 the LArTPC at voltage, and to provide the precision necessary for reconstruction. The tension of 28 subsec:apa_combs 5 N, when combined with the intermediate support combs (described in Section ?? ) ensure that the 29 wires are held taught in place with no sag. Wire sag can impact the precision of reconstruction, 30 as well as the transparency of the TPC. The tension of 5 N is low enough that when the wires 31 are cooled, which increases their tension due to thermal contraction, they will stay safely below 32 subsec:apa_wires the break load of the beryllium copper wire, as described in Section ?? . To further mitigate wire 33 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  22. Chapter 3: Anode Plane Assemblies 3–9 breakage and its impact on detector performance, each wire in the APA is anchored twice on both 1 ends, with both solder and epoxy. 2 3.2.1 Frame and Mesh 3 sec:fdsp-apa-frames Include an image of the subsystem (frame), indicating its parts. Show how the system fits into the overall system (APA). 4 fig:tpc_apa_frame The stainless steel frame of the APA (Figure 3.2) is 6.06 m long, not counting electronics and 5 mounting hardware, and 2.30 m wide. It is 76.2 mm thick, made from imperial size 3-in × 4-in × 6 0.120-in wall rectangular tubing. The cross pieces have a cross-sectional area of 2 in × 3 in, and are 7 fig:tpc_apa_boltedjointdrawing connected to edge pieces using joints, as in Figure 3.3. It is mounted in the cryostat with its long 8 axis vertical; multiple APAs are mounted edge-to-edge to form a continuous plane. An electron 9 sec:apa:electrondiverter deflection technique, described in Section ?? , is used to ensure that electrons drawn towards a 10 joint between two APAs will be deflected to one or the other, and not lost. 11 Figure 3.2: An APA showing overall dimensions and main components. fig:tpc_apa_frame Figure 3.3: A model of the bolted joint. The holes on the top of the tube are for access to tighten the screws. The heads actually tighten against the lower hole, inside the tube. fig:tpc_apa_boltedjointdrawing A fine mesh screen is glued directly to the steel frame surface, over the frame on both sides. It 12 creates a uniform ground layer beneath the wire planes. 13 The mesh is clamped around the perimeter of the opening and then pulled tight (by opening and 14 closing clamps as needed during the process). When the mesh is taut, a 25-mm-wide strip is 15 masked off around the opening and glue is applied through the mesh to attach it to the steel. 16 Although measurements have shown that this gives good electrical contact between the mesh and 17 fig:tpc_apa_fullsizemeshdrawing the frame, a deliberate electrical connection is also made. Figure 3.4 depicts the mesh application 18 setup for a full-size ProtoDUNE-SP APA. 19 Figure 3.4: The mesh clamping jig for the full size APA. fig:tpc_apa_fullsizemeshdrawing 3.2.2 Anchoring Elements and Wire Boards 20 sec:fdsp-apa-boards Include an image of the subsystem (boards), indicating its parts. Show how the system fits into the overall system (APA). 21 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  23. Chapter 3: Anode Plane Assemblies 3–10 Head Electronics Boards 1 At the head end of the APA, stacks of electronics boards (referred to as “wire boards”) are arrayed 2 to anchor the wires. They also provide the connection between the wires and the cold electronics. 3 All APA wires are terminated on the wire boards, which are stacked along the electronics end of the 4 fig:tpc_apa_boardstack APA frame; see Figure 3.5. Attachment of the wire boards begins with the X plane (innermost). 5 After the X-plane wires are strung top to bottom along each side of the APA frame, they are 6 soldered and epoxied to their wire boards and trimmed. The remaining wire board layers are 7 attached as each layer is wound. The main CR boards (capacitive-resistive), which provide DC 8 bias and AC coupling to the wires, are attached to the bottom of the wire board stack. 9 Figure 3.5: Left: View of the APA wire board stack, as seen from the top/side. The wire board layers can be seen at the bottom-left of the illustration, X on the bottom (it doesn’t go all the way back, but extends farther forward and has the main CR board attached), followed by U, V, then G (which doesn’t go all the way forward, and has its own CR board attached). Right: the same stack viewed from below. fig:tpc_apa_boardstack The outermost G-plane wire boards connect adjacent groups of four wires together, and bias each 10 group through an R-C filter whose components are placed on special CR boards that are attached 11 after the wire plane is strung. The X, U and V layers of wires are connected to the CE (housed 12 in boxes mounted on the APA) either directly or through DC-blocking capacitors. The X and U 13 planes have wires individually biased through 50-MΩ resistors. Electronic components for the X- 14 and U-plane wires are located on a common CR board. 15 Mill-Max pins and sockets provide electrical connections between circuit boards within a stack. 16 They are pressed into the circuit boards and are not repairable if damaged. To minimize the 17 possibility of damaged pins, the boards are designed so that the first wire board attached to the 18 frame has only sockets. All boards attached subsequently contain pins that plug into previously 19 mounted boards. This process eliminates exposure of any pins to possible damage during winding, 20 soldering, or trimming processes. 21 Ten stacks of wire boards are installed across the width of each side along the head of the APA. 22 The X-layer board in each stack has room for 48 wires, the V layer has 40 wires, the U layer 40 23 wires and the G layer 48 wires. Each board stack, therefore, has 176 wires but only 128 signal 24 channels since the G wires are not read out. With a total of 20 stacks per APA, this results in 25 2,560 signal channels per APA and a total of 3520 wires starting at the top of the APA and ending 26 at the bottom. There is a total of ∼ 23.4 km of wire on the two surfaces of each APA. Many of the 27 capacitors and resistors that in principle could be on these wire boards are instead placed on the 28 fig:tpc_apa_electronics_connectiondiagram attached CR boards to improve their accessibility in case of component failure. Figure 3.6 depicts 29 the connections between the different elements of the APA electrical circuit. 30 At the head end of the APA, the wire-plane spacing is set by the thickness of these wire boards. 31 The first layer’s wires solder to the surface of the first board, the second layer’s wires to the surface 32 of the second board, and so on. For installation, temporary toothed-edge boards beyond these wire 33 boards align and hold the wires until they are soldered to pads on the wire boards. After soldering, 34 the extra wire is snipped off. 35 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  24. Chapter 3: Anode Plane Assemblies 3–11 Figure 3.6: Diagram of the connection between the APA wires, viewed from the APA edge. The set of wire boards within a stack can be seen on both sides of the APA, with the CR board extending further to the right, providing a connection to the cold electronics, which are housed in the boxes at the far right of the figure. fig:tpc_apa_electronics_connectiondiagram CR Boards 1 sec:crboards The CR boards carry a bias resistor and a DC-blocking capacitor for each wire in the X and U 2 planes. These boards are attached to the board stacks after fabrication of all wire planes. Electrical 3 connections to the board stack are made though Mill-Max pins that plug into the wire boards. 4 Connections from the CR boards to the CE are made through a pair of 96-pin Samtec connectors. 5 Surface-mount bias resistors on the CR boards have resistance of 50 MΩ are constructed with a 6 thick film on a ceramic substrate. Rated for 2.0-kV operation, the resistors measure 0.12 × 0.24 7 inches. Other ratings include operation from − 55 to +155 C, 5% tolerance, and a 100-ppm/C 8 temperature coefficient. Performance of these resistors at LAr temperature is verified through 9 additional bench testing. 10 The selected DC-blocking capacitors have capacitance of 3.9 nF and are rated for 2.0-kV operation. 11 Measuring 0.22 × 0.25 inches across and 0.10 inches high, the capacitors feature flexible terminals to 12 comply with PC board expansion and contraction. They are designed to withstand 1,000 thermal 13 cycles between the extremes of the operating temperature range. Tolerance is also 5%. 14 In addition to the bias and DC-blocking capacitors for all X- and U-plane wires, the CR board 15 includes two R-C filters for the bias voltages. The resistors are of the same type used for wire 16 biasing except with a resistance of 2 MΩ. Capacitors are 47 nF at 2 kV. Very few choices exist for 17 surface-mount capacitors of this type, and they are exceptionally large. Polyester or Polypropylene 18 film capacitors that are known to perform well at cryogenic temperatures are used. 19 Side and Foot Boards 20 The boards along the sides and foot of the APA have notches, pins and other location features to 21 hold the wires in the correct position as they wrap around the edge from one side of the APA to 22 the other. 23 G10 circuit board material is ideal for these side and foot boards due to its physical properties 24 alone, but it has an additional advantage: a number of hole or slot features in the edge boards 25 provide access to the underlying frame. In order that these openings are not covered by wires, 26 the sections of wire that would go over the openings are replaced by traces on the boards. After 27 the wires are wrapped, the wires over the opening are soldered to pads at the ends of the traces, 28 fig:tpc_apa_sideboardmodel and the section of wire between the pads is snipped out (Figure 3.7). These traces are easily and 29 economically added to the boards by the many commercial fabricators who make circuit boards. 30 fig:tpc_apa_sideboardphoto The placement of the angled wires are fixed by pins as shown in the right-hand picture of Figure 3.8. 31 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  25. Chapter 3: Anode Plane Assemblies 3–12 Figure 3.7: Model of board with wires showing how traces connect wires around openings in the side boards. The wires are wound straight over the openings, then soldered to pads at the ends of the traces. After soldering the sections between the pads are trimmed away. fig:tpc_apa_sideboardmodel Figure 3.8: Boards with injection molded tooth strips glued on. The left shows an end board with teeth for fixing the position of the longitudinal wires. The teeth there form small notches. The right is a side board for fixing the position of the angled wires where the wires are angled around a pin. (These boards are prototype test pieces and are not used in the production APAs.) fig:tpc_apa_sideboardphoto The wires make a partial wrap around the pin as they change direction from the face of the APA 1 to the edge. The X- and G-plane wires are not pulled to the side so they cannot be pulled against 2 fig:tpc_apa_sideboardphoto a pin. Their positions are fixed by teeth with slots, as shown in the left-hand picture in Figure 3.8. 3 The polymer used for the strips is Vectra e130i (a trade name for 30% glass filled liquid crystal 4 polymer or LCP). It retains its strength at cryogenic temperature and has a CTE similar enough 5 to G10 that differential expansion/contraction is not a problem. 6 Glue and Solder 7 The ends of the wires are soldered to pads on the edges of the wire boards. Solder provides both 8 an electrical connection and a physical anchor to the wires. As an additional physical anchor, 9 fig:tpc_apa_sideboardphoto roughly 10 mm of the wires are glued near the solder pads. For example, in Figure 3.8, in addition 10 to soldering the wires on the pads shown in the left-hand photograph, an epoxy bead is applied 11 on the wires in the area between the solder pads and the injection-molded tooth strips. 12 Gray epoxy 2216 by 3M is used for the glue. It is strong, widely used (therefore much data is 13 available), and it retains good properties at cryogenic temperatures. A 62% tin, 36% lead and 2% 14 silver solder was chosen. A eutectic mix (63/37) is the best of the straight tin/lead solders but the 15 2% added silver gives better creep resistance. 16 3.2.3 Wires 17 sec:fdsp-apa-wires Beryllium copper (CuBe) wire is known for its high durability and yield strength. It is composed 18 of ∼ 98% copper, 1.9% beryllium, and a negligible amount of other elements. The APA wire has 19 a diameter of 150 µ m (.006 in), and is strung in varying lengths across the APA frame. Three 20 key properties for its usage in the APA are: low resistivity, high tensile or yield strength, and 21 coefficient of thermal expansion suitable for use with the APA’s stainless steel frame. 22 tab:wire Tensile strength of the wire describes the wire-breaking stress (see Table 3.4). The yield strength 23 is the stress at which the wire starts to take a permanent (inelastic) deformation, and is the 24 important limit stress for this case, though most specifications give tensile strength. Fortunately, 25 for the CuBe alloys of interest, the two are fairly close to each other. Based on the tensile strength 26 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  26. Chapter 3: Anode Plane Assemblies 3–13 of wire purchased from Little Falls Alloy (over 1,380 MPa or 200,000 psi), the yield strength is 1 greater than 1,100 MPa. Given that the stress while in use is around 280 MPa, this leaves a 2 comfortable margin. 3 The coefficient of thermal expansion (CTE) describes how material expands and contracts with 4 changes in temperature. The CTEs of CuBe alloy and 304 stainless steel are very similar. Inte- 5 cryo-mat-db grated down to 87 K, they are 2.7e-3 for stainless and 2.9e-3 for CuBe [ ? ]. Since the wire contracts 6 slightly more than the frame during cool-down the wire tension increases. If it starts at 5 N, the 7 tension rises to about 5.5 N when everything is cool. 8 The change in wire tension during cool-down could also be a concern. In the worst case, the wire 9 cools quickly to 87 K before any significant cooling of the frame – a realistic case because of the 10 differing thicknesses. In the limiting case, with complete contraction of the wire and none in the 11 frame, the tension would be expected to reach ∼ 11.7 N. This is still well under the ∼ 20 N yield 12 tension. In practice, the cooling will be done gradually to avoid this tension spike as well as other 13 thermal shock to the APA. 14 Table 3.4: Tensile strength and coefficient of thermal expansion (CTE) of beryllium copper (CuBe) wire. Value Parameter Tensile Strength (from property sheets) (psi) 208,274 Tensile Strength (from actual wire) (psi) 212,530 CTE of CuBe, integrated to 87 K (m/m) 2.9e-3 CTE of 304 stainless steel, integrated to 87 K (m/m) 2.7e-3 tab:wire 3.2.4 Quality Assurance 15 sec:fdsp-apa-qa Ideas from the QA plan - topics to address 16 Work processes: ensure proper training materials for and training of designers, fabricators, etc. 17 Design validation: APA has had design reviews, and is prototyped in ProtoDUNE-SP... 18 Acceptance Testing of procured items? 19 Lessons learned 20 Documents and records for all these things. 21 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  27. Chapter 3: Anode Plane Assemblies 3–14 3.3 Production and Assembly 1 sec:fdsp-apa-prod-assy 3.3.1 Production Plan 2 sec:fdsp-apa-prod-plan 3.3.2 Facility Plans 3 sec:fdsp-apa-facility 3.3.3 Wire Winding Machine 4 sec:fdsp-apa-winding 3.3.4 Tooling 5 sec:fdsp-apa-tooling 3.3.5 Assembly Procedures, Travelers, and Documentation 6 sec:fdsp-apa-assy 3.4 Interfaces 7 sec:fdsp-apa-intfc It would be nice to coordinate with the interface documents; email to Jack F sent 12/20 8 Include an image of each interface in appropriate section. 9 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  28. Chapter 3: Anode Plane Assemblies 3–15 3.4.1 LBNF Cryostat and Detector Support Structure 1 sec:fdsp-apa-intfc-lbnf-dss 3.4.2 Photon Detection System 2 sec:fdsp-apa-intfc-pds 3.4.3 TPC Electronics 3 sec:fdsp-apa-intfc-elec 3.5 Installation, Integration and Commissioning 4 sec:fdsp-apa-install 3.5.1 Transport and Handling 5 sec:fdsp-apa-install-transport 3.5.2 Integration with PDS and TPC Electronics 6 sec:fdsp-apa-install-pds-elec 3.5.3 Calibration 7 sec:fdsp-apa-install-calib 3.6 Quality Control 8 sec:fdsp-apa-qc 3.6.1 Protection and Assembly (Local) 9 sec:fdsp-apa-qc-local 3.6.2 Post-factory Installation (Remote) 10 sec:fdsp-apa-qc-remote 3.7 Safety 11 sec:fdsp-apa-safety Points taken from doc 2145, dune mgmt plan 12 IPO provides an installation resource where either critical safety issues exist (for example, crane 13 operation) or effort is needed which spans all detector elements (material transport). What’s 14 required for APA? 15 Is there a Detector Integration, Testing and Installation (DITI) Group with safety being one aspect 16 of their responsibility? 17 Slow controls safety system – is this relevant? 18 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  29. Chapter 3: Anode Plane Assemblies 3–16 3.8 Organization and Management 1 sec:fdsp-apa-org 3.8.1 APA Consortium Organization 2 sec:fdsp-apa-org-consortium I asked Maxine about standardized org charts for each consortium. It would be nice to have these. Anne 3 3.8.2 Planning Assumptions 4 sec:fdsp-apa-org-assmp 3.8.3 WBS and Responsibilities 5 sec:fdsp-apa-org-wbs 3.8.4 High-level Cost and Schedule 6 sec:fdsp-apa-org-cs 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  30. Chapter 4: High Voltage System 4–17 Chapter 4 1 High Voltage System 2 ch:fdsp-hv 4.1 High Voltage System (HV) Overview 3 sec:fdsp-hv-ov 4.1.1 Introduction 4 sec:fdsp-hv-intro A liquid argon cryostat requires an equipotential plane of high voltage (CPA-plane), and a precisely 5 regulated interior electric field to drive electrons from particle interactions to the sensor planes 6 (APA’s, see volume 3A). This requires planar components (CPA’s) held at high voltage, and 7 formed sets of conductors at graded voltages on the top and bottom (FC’s) and sides (EW-FC’s) 8 of the central drift volume. After a discussion of the materials used in construction, this document 9 will discuss the CPA-plane first, followed by the field shaping components. 10 Include an image of the overall system, indicating its parts. Show how the system fits into the overall detector. 11 figure-label The operating principle is illustrated in Figure ?? ... (add figure) 12 Figure 4.1: required full caption (Credit: xyz) fig:figure-label 4.1.2 Design Considerations 13 sec:fdsp-hv-des-consid This section contains best practices and requirements, as well as interferences and experience from 14 ProtoDune. A discussion of MONITORING REQUIREMENTS will also come here. 15 ... 16 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  31. Chapter 4: High Voltage System 4–18 Anne suggests: Within this section add ref to requirements document when it’s ready, and maybe list the most important half dozen in a table here). E.g., 1 Table 4.1: Important requirements on the HV system design Requirement ... apaphysicsparams By the end of the volume, for every requirement listed in this section, there should exist an explanation of how it will be satisfied. 2 4.1.3 Scope (Rob) 3 sec:fdsp-hv-scope The scope of the HV system includes the continued procurement of materials for, and the fabrica- 4 tion, testing, delivery and installation of the following systems: 5 The TPC has a central Cathode Plane (CPA-plane), 7m wide and 6m tall, with two symmetric 6 drift volumes on both sides. The Cathode Plane is assembled from 6 side-by-side Cathode Plane 7 Assemblies (CPA’s). Each CPA is 1.2m in width and 6m tall, formed from 3 vertically stacked 8 modules, and supported from above by the CPA installation rail, through a single link. A CPA 9 consists of a FR4 frame that encloses and supports the resistive panels (modules). Each CPA is 10 approximately 1.1m wide and 6m long and is constructed from three modules. Six CPA’s together 11 form the CPA plane. The sides of the drift volumes on both sides of the CPA-plane are covered by 12 the FC and EW-FC field cage modules to define a uniform drift field of 500V/cm, which decreases 13 gradually over 3.6m from the high voltage CPA (-180kV) to ground potential at the APA sensor 14 planes, . The cathode bias is provided by an external high voltage power supply through an HV 15 feedthrough connecting to the CPA-plane inside the cryostat. The Field Cage modules have two 16 distinctive types: the top/bottom (FC), and the end wall (EW-FC). Each module is constructed 17 from an array of roll-formed aluminum open profiles supported by two FRP (fiber reinforced 18 plastic) structural beams. A resistive divider chain interconnects all the metal profiles to provide 19 a linear voltage gradient between the cathode and anode planes. The top/bottom modules are 20 nominally 2.3m wide by 3.6m long. 21 A ground plane of tiled perforated stainless steel sheet panels is mounted on the outside surface 22 of each of the top/bottom field cage modules with a 20cm clearance. The top and bottom FC 23 modules are supported by the CPAs and APAs. The end wall modules are 1.5m tall by 3.6m 24 long. They are stacked 4 units high to cover the 6m height of the TPC. These EW-FC modules 25 are supported by the installation rails above the APAs and CPAs, which are part of the Detector 26 Support Structure (DSS). 27 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  32. Chapter 4: High Voltage System 4–19 4.2 HV System Design 1 sec:fdsp-hv-design 4.2.1 High Voltage Power Supply and Feedthrough (Sarah) 2 4.2.2 CPA (Vic, Steve) 3 4.2.3 Field Cages 4 Top and Bottom field cages (Mike) 5 Discussion of Top and Bottom field cages comes here. 6 Endwall field cages (Thomas) 7 Discussion of Endwall Field cages comes here. 8 4.2.4 Electrical Interconnections (Glenn) 9 4.2.5 Quality Assurance 10 sec:fdsp-hv-qa Include an image of the subsystem, indicating its parts. Show how the system fits into the overall system). 11 4.3 Production and Assembly 12 sec:fdsp-hv-prod-assy 4.3.1 Power Supplies and Feedthroughs 13 sec:fdsp-hv-supplies-feedthroughs Discussion of parts procurement, assembly, and testing. 14 4.3.2 CPA 15 sec:fdsp-hv-supplies Discussion of parts procurement, assembly, and testing. 16 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  33. Chapter 4: High Voltage System 4–20 4.3.3 Field Cages 1 Top and Bottom field cages 2 Discussion of parts procurement, assembly, and testing. 3 Endwall field cages 4 Discussion of parts procurement, assembly, and testing. 5 4.3.4 Electrical Interconnections 6 Discussion of parts procurement, assembly, and testing. 7 4.4 Interfaces (Bo) 8 There will be an excellent table of interfaces, and accompanying text. sec:fdsp-hv-intfc 9 Include an image of each interface in appropriate section. 10 Add in appropriate subsections for the pieces that HV interfaces with. These initial ones may not be right. 11 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  34. Chapter 4: High Voltage System 4–21 4.4.1 Interfaces to APA 1 sec:fdsp-hv-intfc-cpa-fc 4.4.2 Interface to DSS 2 sec:fdsp-hv-intfc-dss 4.4.3 Interface to PDS 3 sec:fdsp-hv-intfc-pds 4.4.4 Interface to CE 4 sec:fdsp-hv-intfc-ce 4.4.5 Interface to Calibration 5 sec:fdsp-hv-intfc-cal 4.5 Installation, Integration and Commissioning 6 sec:fdsp-hv-install 4.5.1 Transport and Handling 7 sec:fdsp-hv-install-transport 4.5.2 Integration 8 sec:fdsp-hv-install-pds-elec 4.6 Quality Control 9 There will be excellent quality control, based on documented assembly, testing, transport, and 10 installation procedures. sec:fdsp-hv-qc 11 4.6.1 Protection and Assembly (Local) 12 sec:fdsp-hv-qc-local 4.6.2 Post-factory Installation (Remote) 13 sec:fdsp-hv-qc-remote 4.7 Safety 14 Safety will be the highest priority at all times. There will be documented assembly, testing, 15 transport, and installation procedures. sec:fdsp-hv-safety 16 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  35. Chapter 4: High Voltage System 4–22 4.8 Organization and Management 1 sec:fdsp-hv-org 4.8.1 HV System Consortium Organization 2 sec:fdsp-hv-org-consortium 4.8.2 Planning Assumptions 3 sec:fdsp-hv-org-assmp 4.8.3 WBS and Responsibilities 4 sec:fdsp-hv-org-wbs 4.8.4 High-level Cost and Schedule 5 sec:fdsp-hv-org-cs 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  36. Chapter 5: TPC Electronics 5–23 Chapter 5 1 TPC Electronics 2 ch:fdsp-tpc-elec 5.1 System Overview 3 sec:fdsp-tpc-elec-ov Some initial text suggested by Anne (in fact the APA section in the protodune SP TDR has a lot of good descriptive text) 4 5.1.1 Introduction 5 sec:fdsp-tpc-elec-ov-intro The TPC Electronics System provides the ... The system includes (whatever it includes), as shown 6 in Figure.... 7 Include an image of the overall system, indicating its parts. Show how the system fits into the overall detector. 8 figure-label The operating principle is illustrated in Figure ?? ... (add figure) 9 Figure 5.1: required full caption (Credit: xyz) fig:figure-label 5.1.2 Design Considerations 10 sec:fdsp-tpc-elec-ov-consid The TPC Electronics system design must enable... ... 11 Anne suggests: Within this section add ref to requirements document when it’s ready, and maybe list the most important half dozen in a table here). E.g., 12 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  37. Chapter 5: TPC Electronics 5–24 Table 5.1: Important requirements on the TPC Electronics system design Requirement ... apaphysicsparams By the end of the volume, for every requirement listed in this section, there should exist an explanation of how it will be satisfied. 1 5.1.3 Scope and Requirements 2 sec:fdsp-tpc-elec-ov-scope The scope of the TPC Electronics system includes the continued procurement of materials for, and 3 the fabrication, testing, delivery and installation of the following systems: 4 Whatever the items are... 5 • power supplies 6 • feedthroughs, ... 7 5.2 System Design 8 sec:fdsp-tpc-elec-design Include an image of the subsystem, indicating its parts. Show how the system fits into the overall system). 9 not sure what subsections are needed: power supplies, feedthroughs? 10 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  38. Chapter 5: TPC Electronics 5–25 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  39. Chapter 5: TPC Electronics 5–26 5.2.1 Grounding and Shielding 1 sec:fdsp-tpc-elec-design-ground 5.2.2 Distribution of Wire-Bias Voltages 2 sec:fdsp-tpc-elec-design-bias 5.2.3 Front-End Mother Board (FEMB) 3 sec:fdsp-tpc-elec-design-femb Overview 4 sec:fdsp-tpc-elec-design-femb-ov Front-End ASIC 5 sec:fdsp-tpc-elec-design-femb-fe ADC ASIC 6 sec:fdsp-tpc-elec-design-femb-adc COLDATA ASIC 7 sec:fdsp-tpc-elec-design-femb-coldata Cold Electronics Box 8 sec:fdsp-tpc-elec-design-femb-box Alternative Designs 9 sec:fdsp-tpc-elec-design-femb-alt 5.2.4 Cold Electronics Feedthroughs and Cold Cables 10 sec:fdsp-tpc-elec-design-ft 5.2.5 Warm Interface Electronics 11 sec:fdsp-tpc-elec-design-warm 5.2.6 External Power and Supplies 12 sec:fdsp-tpc-elec-design-external 5.3 Production and Assembly 13 sec:fdsp-tpc-elec-prod 5.3.1 ASIC Procurement 14 sec:fdsp-tpc-elec-prod-asic 5.3.2 Board Assembly 15 sec:fdsp-tpc-elec-prod-board 5.3.3 Cables 16 sec:fdsp-tpc-elec-prod-cables 5.4 Interfaces 17 sec:fdsp-tpc-elec-intfc Include an image of each interface in appropriate section. 18 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  40. Chapter 5: TPC Electronics 5–27 Add in appropriate subsections for the pieces that TPC Electronics interfaces with. These ini- tial ones may not be right. 1 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  41. Chapter 5: TPC Electronics 5–28 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  42. Chapter 5: TPC Electronics 5–29 5.4.1 APAs 1 sec:fdsp-tpc-elec-intfc-apa 5.4.2 DAQ 2 sec:fdsp-tpc-elec-intfc-daq 5.4.3 Other Interfaces 3 sec:fdsp-tpc-elec-intfc-other 5.5 Quality Assurance 4 sec:fdsp-tpc-elec-qa 5.5.1 Initial Design Validation 5 sec:fdsp-tpc-elec-qa-initial 5.5.2 Integrated Test Facilities 6 sec:fdsp-tpc-elec-qa-facilities ProtoDUNE-SP 7 sec:fdsp-tpc-elec-qa-facilities-pdune Small Test TPC 8 sec:fdsp-tpc-elec-qa-facilities-small Additional Test Facilities 9 sec:fdsp-tpc-elec-qa-facilities-other 5.6 Quality Control 10 sec:fdsp-tpc-elec-qc 5.6.1 Production (Local) 11 sec:fdsp-tpc-elec-qc-local 5.6.2 Post-factory Installation (Remote) 12 sec:fdsp-tpc-elec-qc-remote 5.7 Installation, Integration, and Commissioning 13 sec:fdsp-tpc-elec-install 5.7.1 Installation and Integration with APAs 14 sec:fdsp-tpc-elec-install-apa 5.7.2 Cabling 15 sec:fdsp-tpc-elec-install-cabling 5.7.3 Calibration 16 sec:fdsp-tpc-elec-install-calib 5.8 Safety 17 sec:fdsp-tpc-elec-safety 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal 5.9 Organization and Management 18 sec:fdsp-tpc-elec-org

  43. Chapter 6: Photon Detection System 6–30 Chapter 6 1 Photon Detection System 2 ch:fdsp-pd Chapter editor: Wilson 3 6.1 Photon Detection System (PD) Overview 4 sec:fdsp-pd-ov (Length: TDR=10 pages, TP=3 pages) 5 6.1.1 Introduction 6 sec:fdsp-pd-intro Content: Segreto 7 Liquid Argon is known to be an abundant scintillator and emits about 40 photons/keV when 8 excited by minimum ionizing particles, in absence of electric fields. The passage of ionizing ra- 9 diation in LAr produces excitations and ionizations of the argon atoms which ends up with the 10 formation of the excited dimer Ar 2 ∗ . Photons’ emission proceeds through the de-excitation of the 11 lowest lying singlet and triplet excited states, 1 Σ and 3 Σ to the dissociative ground state. The 12 de-excitation from the 1 Σ state is very fast and has a characteristic time of the order of τ fast 13 ≃ 6 ns. The de-excitation from the 3 Σ state is much slower with a characteristic time of τ slow 14 ≃ 1.3 µ sec, since it is forbidden by the selection rules. The relative abundance of the fast and 15 slow components is related to the ionization density of LAr and depends on the ionizing par- 16 ticle, being 0.3 for electron, 1.3 for alpha particles and 3 for neutrons. This circumstance is at 17 the base of the particle discrimination capabilities of LAr, which is exploited by many experiments. 18 19 In both decays, photons are emitted in a 10 nm band centered around 127 nm, in the Vacuum 20 Ultra Violet (VUV) region of the electromagnetic spectrum. 21 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  44. Chapter 6: Photon Detection System 6–31 1 The paradigm for the detection of LAr scintillation light foresees the use of wavelength shifters 2 since the common (cryogenic) photosensors are not sensitive to VUV radiation due to the lack of 3 transparency of fused silica and glass optical windows. The most widely used wavelength shifter 4 used in combination with LAr is Tetra-PhenylButadiene (TPB), which absorbs VUV photons and 5 re-emits them with a spectrum centered around 430 nm, where most of the photosensors have 6 their maximum Quantum Efficiency. TPB conversion efficincy is known to be high, when com- 7 pared to other wavelength shifters (....), and it is often assumed to be 100%, even if a reliable direct 8 measurement of this relevant quantity is not available in the literature. In large LAr TPC, it is 9 common to use photon collector systems which allow to collect light from large areas and drive it 10 in an efficient way towards the active sensors. 11 12 Scintillation light detection is important in a LAr TPC: it is often used for triggering purposes 13 and T 0 time measurements, for the determination of the absolute position of the event inside the 14 active volume, but can also give accurate calorimetric measurements of the deposited energy and 15 is a powerful instrument for particle identification. 16 17 At the moment, the photon detection system of the DUNE Single Phase far detector is required 18 to measure the T 0 of non-beam events with deposited energy above 200 MeV (proton decay and 19 atmospheric neutrinos) with high efficiency to enable 3D spatial localization of candidate events. 20 The photon system will provide the T 0 timing of events relative to TPC timing with a resolution 21 better than 1 µ sec. The minimum light yield requirement is of 0.1 phel/MeV for events near the 22 cathode, which is the farthest region from the Photon Detection System, installed behind the 23 anodic plane. A revision of these requirements is being considered in order to better exploit the 24 characteristics of LAr scintillation light and to improve the performances of the detector for low 25 energy (Supernova) events. 26 Include an image of the overall system, indicating its parts. Show how the system fits into the overall detector. 27 figure-label The operating principle is illustrated in Figure ?? ... (add figure) 28 Include summary of simulation status? Szelc/Himmel 29 6.1.2 Design Considerations 30 sec:fdsp-pd-des-consid Content: Segreto/Warner/Mualem 31 The photon detection system of the Single Phase DUNE far detector is constrained to be structured 32 into modules shaped in form of thin bars (less then 1 cm thick) with approximate dimensions of 33 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  45. Chapter 6: Photon Detection System 6–32 8 cm × 200 cm by the need of being installed on the mechanical frame of the APA and slided 1 between the wire planes on its two sides. 2 Three different designs of PD modules have been developed and are being considered by the SP 3 PD COnsortium. Two of them are based on the concept of light guides coupled to solid state 4 silicon photomultipliers (SiPM) while the third one, namely the ARAPUCA, is a light trap, which 5 captures the photons inside boxes with higlhly reflective internal surfaces where they are eventually 6 detected by SiPM. 7 The dip-coated light guides are pre-treated commercially-cut acrilic slabs dip coated with a solution 8 of TPB, acrylic and toluene. When toluene evaporates it leaves a thin film of TPB embedded in 9 acrylic matrix which acts as wavelenght shifter. A fraction of the light is captured inside the acrylic 10 bar by total internal reflection and is detected at one end of the bar by an array of SiPM. 11 The double-shift light guides are slightly different, since the conversion and guiding processes of 12 the photons are decoupled. They are constituted by a radiator plate coated by pure TPB (through 13 a spraying process) which is optically ocoupled to a commercial shifting/guiding bar which absorbs 14 the TPB blue light and re-emits it in the green. A fraction of the double-shifted light is captured 15 inside the bar by total internal reflections and again it is detected by an array of SiPM installed 16 at one of its ends. 17 The ARAPUCA module is composed of an array of smaller boxes (of the order of 20) each one 18 acting as a smaller detector. Each box has an optical window made by a dichroic filter deposited 19 with two different wavelength shifters, one on the external side and another on the internal one, 20 which allows the light to get inside the box, but not to exit. The internal surface of each box is 21 lined with a highly reflective material so that the trapped photon can bunch several times. An 22 array of SiPM is installed inside the box and will eventually detect the trapped light. 23 The two guiding bars designs have been developed in the course of the last few years and have 24 reached a reasonable level of maturity and reliability. Further improvements are possible and 25 could come from a double ended read-out, that is installing SiPM at both ends of the bars and 26 coating the smaller sides of the bars with reflective foils. Given the maturity of the technology, the 27 effects of these improvements can be easily predicted through Monte Carlo simulations, eventually 28 combined with the outcomes of the protoDUNE experiment where a large number of bars of both 29 flavors are installed (29 of each type). 30 Both designs have been demonstrated to have attenuation lengths for the trapped light compara- 31 ble to the length of the bars themselves, which ensures a reasonable uniformity along the beam 32 direction. Their absolute efficiency has been measured in a quite reliable way only recently and 33 ranges between 0.1% and 0.2%. 34 35 The ARAPUCA concept, on the other hand, is quite new since it was proposed for the first time 36 in 2015 and was accepted for the installation in protoDUNE in mid 2016. A series of LAr tests 37 have been performed with different realizations of ARAPUCA devices, which resulted in efficien- 38 cies ranging from 0.4% to 1.8%. Monte Carlo simulations show that efficiencies at the level of few 39 per cent could be reasonably reached with few modifications to the design. While the results of 40 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  46. Chapter 6: Photon Detection System 6–33 the experimental tests are encouraging, they also show that a deeper understanding of the optical 1 phenomena involved is needed. 2 3 Having the photon detection modules installed only on the anodic plane does not allow to have 4 an uniform light collection over the entire active volume. A possible solution for making the light 5 collection more uniform is to install a reflective foil coated with wavelength shifter on the cathode.. 6 It would be very beneficial to remove the 39 Ar background which otherwise could cause a huge 7 counting rate for events near the anodic plane. It would also increase the light yield of the detector 8 and could allow to perform calorimetric measurements based on light. This possibility is under 9 study through Monte Carlo simulations and its mechanical feasibility is being discussed with the 10 HV Consortium. 11 12 The actual minimal requirements for the light yield of the PD system is of 0.1 phel/keV near the 13 cathode, which would allow to efficiently detect ( > 90%) proton decay events (visible energy > 200 14 MeV). All the three designs satisfies the minimum requirements according to preliminary Monte 15 Carlo studies, but there is a wide consensus inside the Collaboration that an higher light yield 16 would be very beneficial for the detection of low energy Supernova neutrinos and a critical revision 17 of the requirements is taking place. 18 These considerations are driving the actual strategy for the design of the SP FD DUNE far detector 19 design and in particular for the R&D program which will be carried on before the Technical Design 20 Report (mid 2019). A strong effort should be put in exploring the possibilty of increasing the light 21 yield of the detector with the ARAPUCA concept by a factor ten with respect to bars’ read- 22 out, compatibily with the resources available inside the Consortium, in therms of manpower and 23 fundings. This R&D program will lead the Consortium to define a baseline design for the photon 24 collector and one alternate design for risk mitigation. 25 Cocerning the active photosensors few options are under evaluation. SensL SiPM, which have been 26 heavily used in protoDUNE did not demonstrated to be reliable enugh for cryogenic operations 27 after a modification to their packaging and new vendors are being considered. The plan is to use 28 only devices which are certified for cryogenic operations by the vendor. There are actually ongoing 29 tests of cryogenic SiPM produced by Hamamatsu and by FBK (Fondazione Bruno Kessler, Italy). 30 The electronic design will be strongly influenced by the outcomes of Monte Carlo simulations, 31 whcich will tell about the relevance of having pulse shape capabilities and how they improve 32 Supernova neutrino detection. These consideration will have a role in defining the read-out scheme 33 and the digitization frequency of the signals. 34 Anne suggests: Within this section add ref to requirements document when it’s ready, and maybe list the most important half dozen in a table here). E.g., 35 By the end of the volume, for every requirement listed in this section, there should exist an explanation of how it will be satisfied. 36 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  47. Chapter 6: Photon Detection System 6–34 Table 6.1: Important requirements on the PD system design Requirement ... pdphysicsparams 6.1.3 Criteria for photon collection options performance evaluation 1 ? 2 Content: Segreto 3 The performances of the different photon collection options will be evaluated in the facilities 4 available to the Consortium which will allow to perform relative and absolute measurements at 5 room and cryogenic temperature. 6 An important piece of information will come from the protoDUNE experiment, which is being 7 constructed at CERN and will be operated starting from the second half of 2018. 8 All the three different designs are present in protoDUNE, in particular 29 double-shift guides, 9 29 dip-coated guides and 2 ARAPUCA arrays. The presence of the Time Projection Chamber 10 will allow to precisely reconstruct in 3D the track of any ionizing event inside the active volume. 11 The matching of the track with the associated light signal will enable to accurately estimate the 12 relative detection efficiencies of the installed PD modules. Absolute measurements will be possible 13 depending on the accuracy of the Monte Carlo simulations of the optical properties of the detector. 14 Unfortunately the fact that some of the optical parameters which regulate VUV light propagation 15 in LAr are poorly known, such as Ryleigh scattering length, will influence the precision of the 16 absolute measurements. 17 The protoDUNE test will also give the opportunity of performing long term test of the PD mod- 18 ules for the first time. It will be possible to verify if there is a decay in their performances and 19 eventually to quantify it. This is a relevant information, which needs to be taken into account also 20 in the final design of the modules to ensure that the minimal requirements are satisfied along the 21 whole life of the DUNE experiment. 22 23 The R&D program will go on in parallel with the protoDUNE operation and more comparative 24 measurements will be needed before the Technical Design Report, when a baseline design will 25 be singled out. The TallBo facility at Fermilab will be extremely important to this scope. It is 26 constituted by a 450 liters cryostat with 56 cm inner diameter and up to a 183 cm liquid depth 27 and allows to host up to three different PD modules with dimensions close to the real ones. 28 Other facilities are accessible to the Consortium which will allow to test smaller scale prototypes 29 of the modules (or a piece of them), like the SCENE set-up at Fermilab, the cryogenic facilities at 30 Colorado State UNiversity and UNICAMP (Brazil) and the optical facilities at Fermilab, Indiana 31 University and UNICAMP. These facilities will be useful for the single modules optimization 32 process. 33 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  48. Chapter 6: Photon Detection System 6–35 6.2 Scope 1 The scope of the photon detector (PD) system for the DUNE far detector reference design includes 2 design, procurement, fabrication, testing, delivery and installation of the following components: 3 • light collection system; 4 • silicon photo-multipliers (SiPMs); 5 • readout electronics; 6 • calibration system (???) 7 • realted infrastructures 8 6.2.1 Scope 9 sec:fdsp-pd-scope Content: Segreto/Warner/Mualem 10 The scope of the Photon Detection system includes the continued procurement of materials for, 11 and the fabrication, testing, delivery and installation of the following systems: 12 Whatever the items are... 13 • Photon Collectors 14 • SiPMs 15 • ... 16 6.3 PD Design 17 sec:fdsp-pd-design (Length: TDR=50 pages, TP=20 pages) 18 Content: Conveners 19 Include an image of the subsystem, indicating its parts. Show how the system fits into the overall system). 20 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  49. Chapter 6: Photon Detection System 6–36 6.3.1 Photon Collector 1 sec:fdsp-pd-pc Content: Cavanna/Whittington/Machado 2 At the time of the Technical Proposal there are three photon collector options under consideration, 3 in the following we summarize the design and development status for each. [For the Technical 4 Design Report there will be a baseline design and an alternate.] 5 Dip-Coated Light Guides (4 pages) 6 ssec:fdsp-pd-pc-bar1 Content: Toups 7 Double-Shift Light Guides (4 pages) 8 ssec:fdsp-pd-pc-bar2 Content: Whittington 9 The double-shift light guide photon collector design aims to maximize the active VUV-sensitive 10 area of the photon detection system module while minimizing the necessary photocathode (SiPM) 11 coverage. Commercially-fabricated plastic can be manufactured to transport light via total internal 12 reflection with low attenuation losses. However, direct application of coatings to such manufactured 13 optical surfaces can have an adverse impact on the effective attenuation length by introducing or 14 exaggerating imperfections in the surface quality. To maintain the long intrinsic attenuation length 15 of a manufactured light guide, the double-shift light guide design decouples the conversion of VUV 16 photons to optical by arraying acrylic plates coated with TPB in front of a commercially-fabricated 17 polystyrene light guide doped with a second wavelength-shifting compound. 18 fig:DoubleShiftLG-Cartoon Figure 6.1 illustrates the process by which LAr scintillation photons are converted Description 19 and detected by a double-shift light guide module. VUV scintillation photons impinging on the 20 acrylic plates are converted to blue wavelengths. A portion of these blue photons penetrate the 21 light guide and are converted to green. The isotropic re-emission of these green photons leads to a 22 significant fraction becoming trapped by total internal reflection within the light guide. Trapped 23 photons are transported to the end of the light guide where they are detected by an array of SiPMs. 24 Acrylic spray-coated with TPB. TPB absorption and emission Wavelength-Shifting Plates 25 properties. 26 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  50. Chapter 6: Photon Detection System 6–37 128 nm LAr scintillation light SiPM Array 430 nm shifted light from plate ~490 nm shifted light (in bar) 8.6 cm 76.2 cm Figure 6.1: Cartoon schematic of the operation of a double-shift light guide. fig:DoubleShiftLG-Cartoon EJ-280 light guides manufactured by Eljen Technologies 1 . Wavelength-Shifting Light Guide 1 EJ-280 absorption and emission properties. PDE of SiPMs. 2 The double-shift light guide design has undergone a series of development iterations to Testing 3 improve its performance, carried out at Indiana University and at Fermi National Laboratory’s 4 cryogenic and vacuum test facility (PAB). Comparative testing of light guide designs at PAB in 5 bib:JINST-11-C05019 mid-2015 demonstrated the double-shift light guide concept [ ? ]. An improved design similar to 6 that deployed at ProtoDUNE-SP was studied at the Blanche test stand at Fermilab in September 7 of 2016 with a complementary component-wise analyis program at Indiana University afterward, 8 bib:DoubleShiftLG-NIM-171113 detailed in Ref. [ ? ]. The attenuation characteristics of this light guide were measured at Indiana 9 University, while the global quantum efficiency for detecting incident LAr scintillation photons was 10 measured with a vacuum-ultraviolet monochromator at Indiana University and using scintillation 11 light from cosmic rays at the Blanche test stand. 12 Analysis of the double-shift light guide’s attenuation properties determined an Performance 13 attenuation profile in LAr characterized by a double-exponential function of the form f ( z ) = 14 A exp( − z/λ A ) + B exp( − z/λ B ) with z the distance from the instrumented end and parameters 15 bib:DoubleShiftLG-NIM-171113 A =0.29, λ A =4.3cm, B =0.71, and λ B =225 cm [ ? ]. The effective attenuation length is comparable 16 to the width of an APA when the double-shift light guide is deployed in liquid argon. 17 Using both approaches the global quantum efficiency of this detector was determined to be 0.48% 18 at the readout end. Combined with the attenuation function and integrated over the area of 19 the module dimensions planned for the DUNE far detector, this corresponds to an effective area 20 for detecting VUV scintillation photons of 3.7 cm 2 per module. Wavelength-shifting plates are 21 deployed on both sides of the light guide, meaning the double-shift light guide modules in the 22 center APA array are sensitive to scintillation light from two drift volumes and modules in the 23 outer arrays are able to detect scintillation light originating outside of the TPC volume. 24 Simulated response of this module within the DUNE single-phase far detector module indicates 25 this module efficiency should result in an average efficiency for the photon detection system to 26 detect light from neutrino interactions from a galactic supernova of between 30% at 5 MeV and 27 70% at 15 MeV of visible energy. 28 1 http://www.eljentechnology.com 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  51. Chapter 6: Photon Detection System 6–38 The double-shift light guide deployed in Potential Improvements for the DUNE Far Detector 1 the ProtoDUNE-SP APAs was constrained to readout at a single end. Proposed changes to the 2 APA size and cabling routing scheme for the DUNE single-phase far detector would allow for a 3 second array of SiPMs at the opposite end of the light guide. This would double the performance 4 of the photon detection system, raising the per-module effective area to 7.4 cm 2 per module per 5 drift volume. 6 An SiPM with a wavelength-dependent PDE that is better matched to the EJ-280 emission spec- 7 trum would improve the overall efficiency. Simulations of the transport of light within the light 8 guide suggest that applying a highly reflective coating to the long, narrow inactive sides of the 9 light guide would further boost the attenuation function and further increase effective area of the 10 light guide module. These effects combined lead to a potential increase of the effective area to 15 11 cm 2 per module per drift volume. 12 The simulated supernova neutrino detection capability of a photon detection system based on this 13 module depends strongly on small changes in the estimated efficiency. The potential improvements 14 described above raise the physics performance in this channel into a regime where small fluctuations 15 in the module efficiency have a smaller impact on the efficiency to detect these supernova neutrino 16 interactions. These improvements are an important component to risk mitigation in the photon 17 detection system performance. 18 ARAPUCA (4 pages) 19 ssec:fdsp-pd-pc-arapuca Content: A.A.Machado (?) 20 May not have figures integrated yet (or bibliography) - LMM 21 The ARAPUCA is a device based on a new technology that should allow to collect photons with a 22 window of big area with detection efficiencies at the level of several percent while using a coverage 23 with active devices at the permil level. The idea at the basis of the ARAPUCA is to trap photons 24 inside a box with highly reflective internal surfaces, so that the detection efficiency of trapped 25 arapuca_jinst photons is high even with a limited active coverage of its internal surface [ ? ]. 26 27 Photons trapping is achieved by using a smart wave-shifting technique and the technology of the 28 dichroic shortpass optical filters. The latter are multilayer thin films with the property of be- 29 ing highly transparent to photons with a wavelength below a tunable cut-off while being almost 30 perfectly reflective to photons with wavelength above the cut-off. A dichroic shortpass filter de- 31 posited with two different wavelength shifters (one on each side) will be the core of the device. 32 In particular, it will be the acceptance window of the ARAPUCA. The rest of the device will 33 be a flattened box with internal surfaces covered by highly reflective acrylic foils (3M-VIKUITI 34 VIKUITI ESR [ ? ], for example), closed on the top by the dichroic filter deposited with the two shifters. In 35 principle the box can be filled with any kind of transparent material, since it is inessential to its 36 operation. A fraction of the box internal surface is occupied by the active photo-sensors (Silicon 37 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  52. Chapter 6: Photon Detection System 6–39 arpk Photomultipliers - SiPM) that detect trapped photons (figure 6.2). 1 Figure 6.2: Drawing of two ARAPUCAs, each one read-out by 12 SiPMs. This design has been used for the protoDUNE ARAPUCAs. arpk The operating principle is straightforward. 2 The shifters deposited on the two faces of the dichroic filter, S 1 and S 2 respectively, must have 3 their emission wavelengths, L 1 and L 2 , such that: L 1 < L cut − off < L 2 , where L cut − off is the cut-off 4 wavelength of the filter, that is the limit between the region of full transparency (typically > 95%) 5 and that of full reflectivity (typically > 98%). The side of the filter deposited with S 2 faces the 6 internal part of the box. 7 Assuming that the ARAPUCA, observes a LAr volume, scintillation VUV photons ( λ ∼ 127 nm) 8 produced by the passage of an ionizing radiation, hit the window of the device and are shifted 9 to a wavelength of L 1 by the shifter deposited on the external face of the filter and enter the 10 ARAPUCA. Once passed the filter, the photons are converted to the wavelength L 2 and are forced 11 to remain trapped inside the box: its internal surface is covered with an almost perfect reflector to 12 L 2 and the filter that closes the box is itself reflective to L 2 photons. Photons are trapped inside 13 the box. After few reflections the photons are detected by the active photo-sensor installed on the 14 arapuca internal surface of the ARAPUCA (figure 6.3). 15 The net effect of the ARAPUCA is to amplify the active area of the SiPM used to readout the 16 trapped photons. It is easy to show that for small values of SiPM coverage of the internal surface 17 the amplification factor is equal to 18 1 A = (6.1) 2(1 − R ) where R is the average value of the reflectivity of the internal surfaces. For an average reflectivity 19 of 0.95 the amplification factor is equal to ten. 20 Figure 6.3: ARAPUCA and the schematic representation of the operating principle arapuca 6.4 Tests of the technology 21 testsec 6.4.1 Tests performed in Brazil 22 subsec:testlnls Tests of the ARAPUCA in a liquid argon (LAr) environment were performed at the facilities of the 23 Toroidal Grating Monochromator (TGM) beamline of the Brazilian Synchrotron Light Laboratory 24 LNLS_test (LNLS) (Fig. 6.4). 25 A small ARAPUCA made of PTFE with internal dimensions of 3.5x2.5x0.6 cm 3 was tested and 26 a dichroic filter with dimensions of 3.5x2.5 cm 2 and cut-off at 400 nm was used as the window 27 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  53. Chapter 6: Photon Detection System 6–40 of the device. The filter was evaporated with p-TerPhnyl (pTP), which absorbs 127 nm photons 1 and reemits them around 350 nm, on the external side and TetraPhnyl-Butadiene (TPB) on the 2 internal side, which absorbs the shifted 350 nm photons and reemits around 430 nm. Trapped light 3 was detected by a single 0.6x0.6cm 2 SensL SiPMs mod C60035. The device was installed inside 4 a vacuum tight stainless-steel cylinder closed by two CF100 flanges. The cylinder was deployed 5 inside a LAr open bath, vacuum pumped down to a pressure around 10 − 6 mbar and then filled 6 with one liter of ultra pure liquid argon. 7 LAr scintillation light emission was produced by an alpha source installed in front of the ARA- 8 PUCA, immersed in liquid argon. Signals were read-out through an Aquiris PCI board and stored 9 on a computer. 10 11 Figure 6.4: ARAPUCA test at LNLS LNLS_test It was possible to estimate the detection efficiency of the ARAPUCA by determining the number 12 of photo-electrons detected in correspondance of the end point of the α spectrum and comparing 13 it with the expected number of photons impinging on the acceptance window for that particular 14 energy value ( ∼ 4.3 MeV), which depends only on known properties of LAr and on the solid anlge 15 subtended by the the ARAPUCA window. A detection efficiency at the level of 1.8 % was found, 16 well consistent with Monte Carlo expectations. 17 6.4.2 Tests performed at FERMILAB 18 subsec:test_fnal Three cryogenic tests have been performed at Fermilab up to now: 19 • the first one was performed in mid-2016 at the Proton Assembly Building (PAB) and the 20 SCENE facility was used. The ARAPUCA prototype had dimensions of 5 . 0 × 5 . 0 × 1 . 0 cm 3 21 with a dichroic window of 5 . 0 × 5 . 0 cm 2 deposited with pTP and TPB, respectively on the 22 internal and external faces. The cut-off of the filter was at 400 nm. Two SensL SiPMs 23 mod C60035 (0 . 6 × 0 . 6 cm 2 active area each) were installed inside the box to detect trapped 24 photons. The ARAPUCA was deployed inside a vacuum tight cryostat filled with ultrapure 25 LAr. An 241 Am alpha source was positioned in front of the window of the device at a distance 26 of 5 cm from its center. The efficiency of the ARAPUCA was estimated taking into account 27 that in this case the alpha particles have a monochromatic energy of about 5.4 MeV. The 28 estimated efficiency in this case was of the order of 1 %, a factor two below what expected 29 due to the sub-optimal quality and uniformity of the pTP and TPB films and to the lack of 30 reflectivity of the inner PTFE surfaces; 31 • the second one was performed at the beginning of 2017 at the PAB, but using a different 32 facility, TallBo, which allowed to test several devices at a time. Eight different ARAPUCAs, 33 with different filters (different producers), different reflectors and different dimensions where 34 tested. The ARAPUCAs were exposed to the 127 nm scintillation light produced by alpha 35 particles emitted by an 241 Am source, mounted on a holder which could be moved with an 36 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  54. Chapter 6: Photon Detection System 6–41 external manipulator in order to place it in front of each prototype. The efficiencies of the 1 installed ARAPUCAs ranged from 0.4 % to 1.0 %. 2 • a third test ws performed at the end of 2017 with an array of eight ARAPUCAs together with 3 two guiding bars (double-shift design) in the TallBo set-up. Data analysis is still ongoing. 4 6.5 ARAPUCA in protoDUNE 5 Two arrays of ARAPUCAs are going to be installed inside protoDUNE to test the devices in a real 6 experimental environment and to directly compare their performances with those of the guiding 7 bars. The first array has been already installed in the APA 3, while the second one will be installed 8 in the APA number 4. 9 Each ARAPUCA arrays is composed by sixteen basic cells. Each cell has the dimensions of 8 cm 10 × 10 cm and is observed by 12 SiPMs (or 6 SIPMs) installed on the bottom side of the cell (6 11 mm × 6 mm each) and which are passively ganged together, so that only one read-out channel is 12 needed for each ARAPUCA (16 channels per array). The ARAPUCA array has total dimensions 13 of approximately 8 cm × 200 cm, exactly the same of a shifting/guiding bar. The first ARAPUCA 14 arapuca_array array installed in protoDUNE is shown in figure (Fig. 6.5). Figure 6.5: ARAPUCA array in protoDUNE arapuca_array 15 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  55. Chapter 6: Photon Detection System 6–42 6.6 Last Considerations 1 The ARAPUCA device is undergoing a strong R&D program which aims to establish its viability 2 as the photon detection system of the single phase DUNE far detector, both in terms of absolute 3 detection efficiency and long term reliability. Since this is a new technology, a strong effort needs 4 to be put in this program in order to reach a full comprehension of the optical processes which are 5 active in the device and reach the target efficiency of few per cent. 6 Hybrid or New Options (2 pages) 7 ssec:fdsp-pd-pc-new 6.6.1 New Techniques to Supplement or Enhance Light Yield 8 sec:fdsp-pd-enh Content: Cavanna/Whittington/Machado 9 Light Concentrators 10 sec:fdsp-pd-assy-lc Content: (1 page) - Cavanna 11 In the current baseline layout, the photosensitive area of the PD system is limited to about 12.5% 12 of the area of the anode plane - delimiting one side of the LArTPC volume. Only a small fraction 13 of the VUV direct light emitted in ionization events is thus intercepted by the photosensitive area, 14 and this fraction also quickly reduces at increasing distance of the event from the anode plane. 15 Methods to increase the amount of light collected by the PDS are being considered, for example 16 by covering the opposite cathode plane with wls-coated reflector foils so that a good fraction of 17 the VUV light is shifted into the Visible, reflected back toward the Anode plane and eventually 18 intercepted by the PDS, if sensitive to this wavelength. 19 Further increase in light collection, both for the VUV and the reflected Vis component, can be 20 achieved by implementing large area reflective surfaces at the anode plane (e.g. in the large open 21 areas between PD bars inside the APA frames) acting as light concentrators toward the smaller 22 photosensitive surfaces. This conceptual solution is suggested from the widely diffused implemen- 23 tation of Winston Cones for enhancing light collection in large volume liquid detectors. The PD 24 bar geometry of the photosensitive area inside the thin APA frames and the related mechanical 25 constraints impose rather severe limitations on the design - cone depth and entrance / exit aper- 26 tures ratio - of the light concentrating surfaces. The installation of the reflective surfaces inside 27 the APA frame would necessarily be made before wire winding. Ongoing studies are expected to 28 demonstrate the feasibility of the solution and move the conceptual scheme into a technical design. 29 MC simulations will determine the efficiency of the light concentrator. 30 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  56. Chapter 6: Photon Detection System 6–43 Hybrid and New Options 1 X-ARAPUCA represents the main line of development of the ARAPUCA photo-detector design 2 aiming to further improve the collection efficiency, while retaining the same working principle, 3 mechanical design and active photo-sensitive coverage. 4 In a sense X-ARAPUCA is a hybrid solution between the ARAPUCA and the wavelength-shifting 5 light guide bar PDS concepts, where photons trapped in the ARAPUCA box are shifted and 6 transported to the readout via total internal reflection in a light guide placed inside the box. 7 This solution minimizes the number of reflections on the internal surfaces of the box and thus 8 the probability of photon loss. Simulations suggest that this modification will lead to a rather 9 significant increase of the collection efficiency. 10 Figure 6.6: X-ARAPUCA design (exploded view). fig:exploded In a standard ARAPUCA the photon trapping effect is obtained by means of a dichroic filter and 11 a two-steps wavelength shifting process, the first from VUV to UV outside the acceptance window 12 of the box and the second inside from UV to blue, across the filter cutoff. Double shifted photons 13 are eventually collected by an array of photosensors (SiPM) distributed on the backplane of the 14 fig:exploded box, opposite to the the acceptance window. In the X-ARAPUCA design, Fig. 6.6, the inner shifter 15 coating/lining over the reflective walls of the box is replaced by a thin wavelength-shifting light 16 guide slab inside the box, of the same dimensions of the acceptance filter window and parallel to 17 it. The SiPM arrays are installed vertically on the sides of the box, in optical contact to the light 18 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  57. Chapter 6: Photon Detection System 6–44 guide thin ends. In this way a fraction of the photons will be converted inside the slab and guided 1 to the read-out, other photons, e.g. those at small angle of incidence below the critical angle of 2 the light guide slab, after conversion at the slab surface will be remain trapped in the box and 3 eventually collected as for the standard ARAPUCA. 4 A full sized X-ARAPUCA prototype is under construction. The light guide is made by a 2 mm 5 thick TPB doped acrylic slab. Specially designed read-out boards have been realized, made of 6 6 passively ganged SiPMs in a strip configuration. Two boards into a single channel readout light 7 signals from the X-ARAPUCA box. 8 9 The photon detectors described in the preceding section represent the results of a long process 10 of optimization of the initial concepts developed years ago. A balance between the cost of the 11 readout electronics (channel count), and the cost and performance of the SiPM’s was achieved 12 with realistic designs of the photon detectors offering the detection efficiency in the range ∼ 0.5 13 to 1.5%. 14 A significant advances in the technology of the SPM’s have been accomplished during this time: 15 the photosensors dark count, after-pulsing and cross-talk rates have been lowered by almost an 16 order of magnitude, whereas the production costs have been dropping significantly in response to 17 the increasing range of applications. The recent studies and tests demonstrate that the improved 18 quality of the photodetectors is permitting much higher degree of ganging (passive or active), 19 thus significantly lowering the “per SiPM" readout costs. These technological trends are likely to 20 continue, thus allowing for a possible alternative concepts of the Photon Detectors, even within 21 the geometrical and cost confines of the baseline detectors. 22 One of the possible different concepts of the Photon Detector includes a long printed circuit board 23 with the overall dimensions identical to the light guide bars or ARAPUCA but with a simpler 24 construction involving only SiPMs distributed over the board surface. The SiPMs can be coated 25 with appropriate waveshifter (TPB or MSB) or a foil with the waveshifter in front of the SiPM 26 can be used to convert the VUV 128 nm Argon light to the blue light at the maximum detection 27 efficiency of the SiPM. The overall detection efficiency of such a “detector element"is expected to 28 be of the order of 25-30%, depending on the pixel size and the fill-factor of the SiPM. A photon 29 detector involving the SiPMs only would offer a major simplification of the construction and 30 integration efforts. Its overall performance can be reliably estimated and it is proportional to the 31 total area of the bar covered with the SiPMs. The performance of the baseline Photon Detectors 32 can be achieved with 2-4% of the area covered with the SiPMs. Taking 1800 cm 2 as a bar surface 33 this coverage can be accomplished with 100-200 SiPMs of the standard 6x6 mm formfactor. With 34 12-fold passive ganging, successfully demonstrated in recent tests, such a solution would require 35 8-16 readout channels per bar. The multiplexing level is limited by the noise of the readout 36 electronics. Significantly higher degree of multiplexing can be achieved by use of larger pixel (like 37 75x75 microns) SiPMs and/or possible cold active ganging circuitry. Such a detector concept 38 appears very flexible and it would allows for future optimization in response to the expected 39 technological advances with no or minimal impact on the rest of the DUNE detector. 40 The Technical Proposal and TDR may include proposals to augment the capabilities of the photon 41 collector modules. In the case that the hardware requirements for such proposals would pose a 42 minimal impact on the detector design, additional R&D beyond the timescale of the TDR may be 43 required since it may impact the second 10 kt module if not the first. Some examples include: 44 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  58. Chapter 6: Photon Detection System 6–45 • TPB-Coated Reflector Foils (Szelc) 1 • Xenon-Doped LAr (Escobar/Para) 2 • TPB-Doped LAr (Escobar) 3 6.6.2 Photon Sensors 4 sec:fdsp-pd-ps Content: (2 pages) - Zutshi 5 The SP DUNE Photon Detector System will use Silicon Photomultipliers, mated to the bar or 6 ARAPUCA photon collector options, to detect scintillation light generated in the LAr. Robust 7 photon detection efficiency, low operating voltages, small size and ruggedness make their usage 8 entirely plausible in the single phase design where the photon detectors are to be accommodated 9 inside the APA frames. The salient guiding principles of this SiPM-based photo-detection system 10 can be stated as: 11 Signal path separate from TPC readout. This implies cables dedicated to bringing the power in 12 and taking the analog or digitized signals from the PD system, out of the cryostat. Feed-through 13 cable space limitations therefore, imply some level of ganging of the SiPM signals inside the LAr 14 volume. 15 The optimal SiPM may depend on the photon collector option. Since all photon collector options 16 being currently considered involve shifting the 128 nm LAr scintillation to varying degrees, the 17 final fine-tuned choice may have to be made after the collector down-select. It should however be 18 kept in mind that the size of these effects, while not anything to sniff at, will not exceed 15-20 %. 19 The Silicon Photomultiplier packaging should allow for tileable arrays to be constructed to facilitate 20 high efficiency mating to the photon collectors and efficient space utilization inside the APA frame. 21 While understanding SiPM requirements (number of devices, dynamic range, triggering, zero- 22 suppression threshold etc.) in light of the physics goals is an ongoing process, it is clear from the 23 R&D carried out so far that devices from a number of vendors have the performance characteristics 24 in the vicinity of that needed for the DUNE photon detector system (see Table xxx). Furthermore, 25 a number and types of these devices are being installed in proto-DUNE which will provide an 26 excellent test bed for evaluating and monitoring SiPM performance in a realistic environment over 27 the medium term. 28 A key requirement, based on past experience, is ensuring the mechanical and electrical integrity 29 of these devices in a cryogenic environment. This is a DUNE requirement which catalog devices 30 from most vendors do not satisfy as they are only certified for operation down to -40C. Thus it 31 is of paramount importance for the DUNE PD Consortium to work with vendors in designing, 32 fabricating and certifying SiPM packaging that is robust and reliable from the point-of-view of 33 long-term operation in a cryogenic environment. Already there is interest from at least two vendors 34 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  59. Chapter 6: Photon Detection System 6–46 (Hamamatsu and FBK) to engage with the Consortium in this fashion with the goal of having the 1 vendor warrantying the product for our application. Contact with other vendors and experiments 2 (e.g. DarkSide) is being pursued. 3 In parallel, comparative performance evaluation of promising SiPM candidates from multiple ven- 4 dors will need to be carried out. This evaluation will not only need to address inherent charac- 5 teristics (gain, dark rate, x-talk, after-pulsing etc) and ganging performance but also form factor, 6 spectral response and mating with regard to the multiple photon collector options. Experience ac- 7 quired from proto-DUNE construction and operation will inform QA/QC plans for the full detector 8 which will need to be delineated in detail. 9 6.6.3 Electronics 10 sec:fdsp-pd-pde Content: (3 pages) - Moreno/Franchi/Djurcic 11 rjw: Include comment whether there are differences between the photon collector options 12 6.6.4 Quality Assurance 13 sec:fdsp-pd-qa Content: (1 page) - Warner 14 6.7 Production and Assembly 15 sec:fdsp-pd-prod-assy (Length: TDR=40 pages, TP=8 pages) 16 6.7.1 Photon Collectors Production 17 sec:fdsp-pd-prod-pc Content: Cavanna/Whittington/Machado 18 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  60. Chapter 6: Photon Detection System 6–47 Dip-Coated Light Guides (2 pages) 1 ssec:fdsp-pd-pc-prod-bar1 Double-Shift Light Guides (2 pages) 2 ssec:fdsp-pd-pc-prod-bar2 The production and assembly of the double-shift light guide modules is divided into separate 3 threads for the wavelength-shifting plates and the EJ-280 light guides. Many of the production, 4 quality assurance, and assembly procedures developed for the double-shift light guide design de- 5 ployed at ProtoDUNE-SP will remain the same for the DUNE single-phase far detector. 6 fig:DoubleShiftLG-SprayedPlates Spray-coating of TPB on acrylic plates (see Fig. 6.7). Manufacture of the WLS Plates 7 Figure 6.7: TPB-coated acrylic plates after spraying at Indiana University during fabrication of parts for ProtoDUNE-SP. fig:DoubleShiftLG-SprayedPlates VUV conversion performance measured for neighboring samples from QA of the WLS Plates 8 the acrylic plate template using a vacuum-ultraviolet monochromator. 9 EJ-280 light guides fabricated by Eljen Technologies. Receipt and QA of the Light Guides 10 fig:DoubleShiftLG-EJ280 Received and scanned in a long dark-box using a blue LED (Fig. 6.8). Measure conversion and 11 transmission to the light guide ends to test attenuation. Direct transmission through the light 12 guide to confirm uniformity. Attenuation length in liquid argon shorter than in air, but long 13 attenuation in air has been shown to correspond to long attenuation in liquid argon. 14 Parts are shipped to the assembly point Assembly of the Double-shift Light Guide Module 15 where the EJ-280 light guide is mounted into the module frame and the WLS plates are attached. 16 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  61. Chapter 6: Photon Detection System 6–48 Figure 6.8: EJ-280 light guide within darkbox for attenuation scan QA at Indiana University (prepared for ProtoDUNE-SP). fig:DoubleShiftLG-EJ280 Figure 6.9: Mounting of the WLS plates to the EJ-280 bar. fig:DoubleShiftLG-PlateMounting 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  62. Chapter 6: Photon Detection System 6–49 ARAPUCA (2 pages) 1 ssec:fdsp-pd-pc-prod-arapuca 6.7.2 APA Frame Mounting Structure and Module Fixing 2 sec:fdsp-pd-assy-frames Content: (2 pages) - Warner 3 Photon detector (PD) modules are inserted into the APA frames through ten slots (five on each 4 side of the APA frame) and are supported in place inside the frame in stainless steel guide channels. 5 The slot dimensions for the ProtoDUNE APA frames were 108.0mm X 19.2mm wide (See fig. 1). 6 The guide channels are pre-positioned into the APA frame prior to applying the wire shielding 7 mesh to the APA frames, and are not accessible following wire wrapping. 8 Insert Dave’s PD Mounting rails in APA frame mpicture 9 Following insertion, the PD modules are fixed in place in the APA frame using two stainless steel 10 captive screws, as shown in figure 2. 11 Insert Dave’s PD Mounting screws mpicture 12 Cryogenic thermal contraction 13 Bar-style PD modules are structurally composed of primarily polycarbonate and acrylic, which 14 have significantly different shrinkage factors compared to the stainless steel APA and PD support 15 frames (see table 1). 16 format table better? 17 tbl:fdsfpdshrink Table 6.2: Shrinkage of Photon Detector Materials 206 ◦ C Drop Material Shrinkage Factor (m/m) Stainless Steel (304) 2 . 7 × 10 − 3 FR-4 G-10 (In-plane) 2 . 1 × 10 − 3 Polystyrene (Average) 1 . 5 × 10 − 2 Acrylic and Polycarbonate (Average) 1 . 4 × 10 − 2 These differences in thermal expansion (or contraction in this case) were important to keep in mind 18 during design of the PD module supports. Mitigation for these varying contractions are detailed 19 in table 2: 20 Needs better table formatting? 21 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  63. Chapter 6: Photon Detection System 6–50 tbl:fdsfpdshrinkeffects Table 6.3: Relative Shrinkage of PD components and APA frame, and mitigations Interface Relative shrinkage Mitigation PD Length to APA width PD shrinks 25.7 mm Rel- PD affixed only at one end of APA frame, ative to APA frame free to contract at other end Width of PD in APA Slot PD shrinks 1.2 mm rela- Photon detector not constrained in C- tive to slot width channels. C channels and tolerances de- signed to contain module across thermal contraction range Width of SiPM mount Stainless frame shrinks Diameter of shoulder screws and FR-4 board ( Hover board ) to 0.06 mm more than PCB board clearance holes selected to allow for stainless steel frame motion Width of SiPM mount Polycarbonate block Allowed for in clearance holes in SiPM board relative to polycar- shrinks 1mm more than mount board bonate mount block PCB PD Mount Frame Deformation under static PD load 1 FEA modeling of the PD support structure was conducted to study static deflection prior to 2 building prototypes. Modeling was conducted in both the vertical orientation (APA upright, 3 as installed in cryostat) and also flat. Basic assumptions used were fully-supported fixed end 4 conditions for the rails, uniform loading of 3X PD mass (5 kg) along rails. Prototype testing 5 confirmed these calculations. 6 Insert Dave’s 4 deflection pictures here 7 Same for bars and ARAPUCAs 8 6.7.3 Photosensor Modules 9 sec:fdsp-pd-assy-psm Content: (1 page) - Zutshi 10 The Silicon Photomultiplier analog signal will be ganged on the detector inside the LAr volume. 11 Passive and active ganging schemes are under consideration. Some passive ganging (sensors put 12 in parallel) schemes have been examined and are being installed inside proto-DUNE (see Fig. 13 yyy). The key point for parallel passive ganging in terms of maintaining signal-to-noise as devices 14 are ganged together is the terminal capacitance of the sensors. This characteristics can therefore 15 play an important in device selection or on the flip side in determining the maximum ganging 16 possible. In this scheme the ganged analog signals are then brought out via long cables ( 25 m) for 17 digitization outside the cryostat. This is currently being done in proto-DUNE using teflon ethernet 18 CAT6 cables. 19 An interesting alternative option that may provide more flexibility in terms of the level of photo- 20 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  64. Chapter 6: Photon Detection System 6–51 sensor ganging possible and also obviate the need for carrying analog signals of long cables is the 1 so-called active ganging option where the amplifiers and ADCs sit on the board carrying the pho- 2 tosensors inside the LAr volume. This option however brings, in all the reliability and long-term 3 stability issues related to cold electronics into play. While active ganging prototypes are under 4 study the design cannot be considered to be at a mature stage at this point and schedule and 5 technical considerations may influence how far this promising option can be pursued. 6 In any case, the SiPMs will need to be surface-mounted on a PCB that can mate efficiently with 7 the photon collector options. proto-DUNE will provide a wealth of operational experience and 8 information on such a design with atleast a passive ganging board. It is already clear, however, 9 that some R&D is needed in optimizing the connectors to be used to couple the cable to the board 10 and understanding the mechanical stresses involved in the SiPM-PCB-Connector system (with a 11 varying CTEs) as it is cooled (or cycled) to cryogenic temperatures. 12 Just cold boards? 13 6.7.4 Assembly Procedures 14 sec:fdsp-pd-assy-ap Content: Cavanna/Whittington/Machado 15 PC assembly modules (ready for APA installation). 16 Can we have a single section that describes how the bars and/or ARAPUCA are assembled into PC modules or do we need a separate subsub(!)section for each? 17 Dip-Coated Light Guide Modules (2 pages) 18 ssec:fdsp-pd-pc-assy-bar1 Double-Shift Light Guide Modules (2 pages) 19 ssec:fdsp-pd-pc-assy-bar2 ARAPUCA Modules (2 pages) 20 ssec:fdsp-pd-pc-assy-arapuca 6.7.5 Electronics 21 sec:fdsp-pd-assy-pde Content: (2 pages) Moreno/Franchi/Djurcic 22 • Components 23 • Boards 24 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  65. Chapter 6: Photon Detection System 6–52 • Cable plant 1 6.7.6 QA 2 sec:fdsp-pd-assy-qa Content: (2 pages) - Warner 3 • Sub-assemblies- same for all modules. 4 • Completed modules- largely same for different option, at least for TP. 5 6.8 System Interfaces 6 sec:fdsp-pd-intfc Content: Kemp 7 (Length: TDR=10 pages, TP=2 pages) 8 Include an image of each interface in appropriate section. 9 This section describes the interface between the DUNE SP Far Detector Photon-Detection System 10 (SP-PDS) and several other consortia, task forces (TF) and subsystems listed below, namely: 11 1. Anode Plane Assembly (APA) 12 2. Feedthroughs 13 3. Cold Electronics (CE) 14 4. Cathode Plane Assembly (CPA) / High Voltage System (HVS): Reflector foils (light en- 15 hancement) 16 5. Data Acquisition (DAQ) 17 6. Calibration / Monitoring 18 The contents of the section are focused on the needs to complete the design, fabrication, installation 19 of the related subsystems, and are organized by the elements of the scope of each subsystem at 20 the interface between them. 21 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  66. Chapter 6: Photon Detection System 6–53 6.8.1 Anode Plane Assembly 1 sec:fdsp-pd-intfc-apa The PDS is integrated in the APA frame to form a single unit for the detection of both ionization 2 charge and scintillation light. 3 Hardware: The hardware interface between APA and PDS has two main components: 4 1. Mechanical: a) supports for the PDS detectors; b) access slots for installation of the detectors, 5 if, as in the present baseline design, the detectors will be installed after the wire winding is 6 completed; c) access slots for the cabling of the PDS detectors; d) routing of the PDS cables 7 inside the side beams of the APA frame. 8 2. Electrical: grounding scheme and electrical insulation, to be defined together with the CE 9 consortium, given the CE strict requirements on noise. 10 Design: Since the design of the PDS detectors is still under evolution, the APA consortium will 11 evaluate different solutions proposed by the PDS consortium that may require modifications of the 12 structure of the APA frame. The evaluation phase is expected to be concluded by Spring 2018. 13 The PDS consortium will provide detailed engineering drawings of the detectors and specifications 14 on the size and number of cables, and of any connectors required. If the PDS detectors will be 15 installed after the wire winding is completed, as in the present baseline design, the APA consortium 16 will evaluate possible variations of the baseline geometry, as suggested by the PDS consortium: 17 larger slot dimensions and increased number of slots. If photon detectors are installed in the 18 APA frame prior to the winding, the PDS consortium is responsible for designing the supports 19 inside the APA frame and providing a protection for the detectors against UV light. The APA 20 consortium will evaluate the proposed design. The APA consortium, together with the CE and 21 PDS consortia, will revisit the requirements on the mesh pitch and wire size, and set specifications 22 for the mesh procurement, compatibly with the availability on the market. The APA consortium 23 will evaluate the feasibility of routing the PDS detector cables inside the side beams of the APA 24 frame, considering also the cabling needs of the Cold Electronics consortium. This may require 25 the evaluation of side beams of larger dimensions. 26 Production: The APA Consortium fabricates all APA-PDS mechanical interface hardware. The 27 PDS consortium fabricates all PDS detectors and electronic boards, and will provide all cables and 28 connectors. 29 Testing: The interface hardware and the interconnect procedures between APA and PDS, in- 30 cluding cabling, are validated at one or more integration/installation trials at an integration test 31 facility. The APA and PDS consortia will be responsible for the procurement of their respective 32 hardware and delivery to the integration test facility. Experts from both groups work with the 33 installation team to perform trial fit and cabling before the final design is completed. Electrical 34 test will be performed with a APA/PDS/CE vertical slice test if available. 35 The PDS consortium will provide procedures and personnel for the commis- Commissioning: 36 sioning of the PDS components. The APA consortium will be responsible for applying the bias 37 voltages on the wire planes. 38 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  67. Chapter 6: Photon Detection System 6–54 6.8.2 Feedthroughs 1 sec:fdsp-pd-intfc-feed 6.8.3 Cold Electronics (CE) 2 sec:fdsp-pd-intfc-feed Hardware: The hardware interfaces between the CE and PDS occur on the chimneys and in the 3 racks mounted on the top of the cryostat which house low and high voltage power supplies for PDS, 4 low and bias voltage power supplies for CE, as well as equipment for the Slow Control and Cryo 5 Instrumentation (SC in the following), and possibly DAQ consortia. There should be no electrical 6 contact between the PDS and CE components except for sharing a common reference voltage point 7 (ground) at the chimneys. An additional indirect hardware interface takes place inside the cryostat 8 where the CE and PDS components are both installed on the APA (responsibility of the single 9 phase far detector APA consortium, APA in the following), with cables for CE and PDS that may 10 be physically located in the same space in the APA frame, and where the cables and fibers for CE 11 and PDS may share the same trays on the top of the cryostat (these trays are the responsibility 12 of the facility and the installation of cables and fibers will follow procedures to be agreed upon in 13 consultation with the underground installation team, UIT in the following). 14 Chimneys: in the current design CE and PDS use separate flanges for the cold/warm transition 15 and each consortium is responsible for the design, procurement, testing, and installation, of their 16 flange on the chimney, together with the LBN facility that is responsible for the design of the 17 cryostat. Racks on top of the cryostat: the installation of the racks on top of the cryostat is 18 a responsibility of the facility, but the exact arrangement of the various crates inside the racks 19 will be reached after common agreement between the CE, PDS, SC, and possibly DAQ consortia. 20 The PDS and CE consortia will retain all responsibilities for the selection, procurement, testing, 21 and installation of their respective racks, unless for space and cost considerations an agreement is 22 reached where common crates are used to house low voltage or high/bias voltage modules for both 23 PDS and CE. Even if both CE and PDS plan to use floating power supplies, the consequences of 24 such a choice on possible cross-talk between the systems needs to be studied. Electrical contacts 25 between PDS and CE components: there should be no electrical contact between the CE and 26 PDS components, neither inside nor outside the cryostat, with the exception of the use of the 27 same reference voltage (grounding) on the chimneys, with each of the CE and PDS has a separate 28 connection to the detector ground (the cryostat). 29 Software: there are no direct interfaces between the CE and PDS systems. Test stands and inte- 30 gration facilities: various test stands and integration facilities will be developed. In all cases the CE 31 and PDS consortia will be responsible for the procurement, installation, and initial commissioning 32 of their respective hardware in these common test stands. The main purpose of these test stands 33 is study the possibility that one system may induce noise on the other, and the measures to be 34 taken to minimize this cross-talk. For these purposes, it is desirable to repeat noise measurements 35 whenever new, modified detector components are available for one or the other consortium. This 36 requires that the CE and PDS consortia agree on a common set of tests to be performed and that 37 the CE consortium can operate the PDS detectors within a pre-determined range of operating 38 parameters, and vice versa, without the need of providing personnel from the PDS consortium 39 when the CE consortium is performing tests or vice versa. Procedures should be set in place to 40 decide the time allocation to tests of the components of one or the other consortium. 41 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  68. Chapter 6: Photon Detection System 6–55 Installation: the installation of the cables for the CE and PDS requires coordination with the 1 APA consortium and the UIT. This applies both for the routing of the CE and PDS cables through 2 the APA frames while the APAs are hanging in the âĂIJtoasterâĂİ, and later, after the APA has 3 been moved inside the cryostat, for the routing of the cables in the trays hanging from the top 4 of the cryostat. The CE consortium will retain the responsibility for the CE cables, and similarly 5 for the PDS consortium, but the possibility that the CE and PDS cables may need to be routed 6 together through the APA frames, may require that the two installation teams cooperate for this 7 task. 8 6.8.4 Cathode Plane Assembly (CPA) / High Voltage System (HVS): Re- 9 flector foils (light enhancement) 10 sec:fdsp-pd-intfc-le This section describes the interface between the light collection boosting system of the SP-PDS and 11 the HVS. These systems interact in the case that the photon detection system includes wavelength- 12 shifting reflector foils mounted on the CPA. 13 Hardware: The purpose of installing the wavelength-shifting (WLS) foils is to allow enhanced 14 detection of light from events near to the cathode plane of the detector. The WLS foils consist of 15 a wavelength shifting material (likely tetraphenyl butadiene - TPB) coated on a reflective backing 16 material. The foils would be mounted on the surface of the cathode plane array (CPA) in order to 17 enhance light collection from events occurring nearer to the CPA, and thus greatly enhancing the 18 spatial uniformity of the light collection system as detected at the APA mounted light sensors. The 19 foils may be laminated on top of the resistive kapton surface of the CPA frames, with the option 20 of using metal fasteners/tacks that would also serve to define the field lines. Production of the 21 FR4+resistive kapton CPA frames are the responsibility of the HV consortium. Production and 22 TPB coating of the WLS foils will be the responsibility of the Photon Detection consortium. The 23 fixing procedure for applying the WLS foils onto the CPA frames and any required hardware will 24 be the responsibility of the Photon Detection consortium, with the understanding that all designs 25 and procedures will be pre-approved by the HV consortium. This new detector component is not 26 being tested in ProtoDUNE, however its integration in the present DUNE far detector HV system 27 could possibly imply performance and stability degradation (due for example to ion accumulation 28 at the CPA surface); the assembly procedure of the CPA/FC module could become more complex 29 due to the presence of delicate WLS foils. Intense R&D will be required before deciding on its 30 implementation. 31 R&D studies: It will be the responsibility of the HV consortium to define testing requirements 32 that will need to be carried out in order to verify that the proposed WLS foil installation will not 33 degrade the performance of the CPA. It will be the responsibility of the PD consortium to carry 34 out these tests. 35 Integration: An integration test stand will likely be employed to verify the proper operation of 36 the CPA panels with the addition of WLS foils under high voltage conditions. Light performance 37 (wavelength conversion and reflectivity efficiency) will also be verified. The HV consortium will 38 be responsible for HV aspects of the test stand and the PD consortium will be responsible for the 39 light performance aspects. 40 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  69. Chapter 6: Photon Detection System 6–56 Installation: The wavelength shifting material (TPB) can degrade under certain environmental 1 conditions, so its addition to the surface of the CPAs will increase the handling requirements 2 during installation. The PD consortia will be responsible for defining the environmental and 3 handling procedures that will ensure minimal degradation of the WLS foil performance. The PD 4 consortium will be responsible for the installation of the WLS foils onto the CPA panels. The HV 5 consortium will be responsible for all other aspects of the installation of the CPA panels. 6 Commissioning: PD and HV consortia will provide staffing for commissioning the CPAs in the 7 cryostat in the following manner... 8 6.8.5 DAQ 9 sec:fdsp-pd-intfc-daq Data Physical Links: Data are passed from the PDS to the DAQ on optical links conforming 10 to an IEEE Ethernet standard. The links run from the PDS readout system on the cryostat to 11 the DAQ system in the Central Utilities Cavern (CUC). 12 Data Format: Data are encoded using a data format based on UDP/IP. The data format is 13 derived from the one used by the Dual Phase TPC readout. Details will be finalized by the time 14 of the DAQ TDR. 15 Data Timing: The data shall contain enough information to identify the time at which it was 16 taken. 17 Data Volume: The DAQ will have provision to receive up to 8GBit/s of data from the PDS per 18 APA. 19 Data Link Speed: The PDS data for each APA may be transmitted either on multiple links 20 following the 1000Base-SX standard or a single link following the 10GBase-SR standard. In either 21 case the fibre will be chosen to give sufficient margin for the distance from the cryostat to the 22 CUC. Details will be finalized by the time of the DAQ TDR. 23 Trigger Information: The PDS may provide summary information useful for data selection. If 24 present, this will be passed to the DAQ on the same physical links as the remaining data. 25 Timing and Synchronization: Clock and synchronization messages will be propagated from the 26 DAQ to the PDS using a backwards compatible development of the ProtoDUNE Timing System 27 protocol ( See Dune docdb-1651 ). There will be at least one timing fibre available for each data 28 links coming from the PDS. Power-on initialization and Start of Run setup: The PDS may require 29 initialization and setup on power-on and start of run. Power on initialization should not require 30 communication with the DAQ. Start run/stop run and synchronization signals such as accelerator 31 spill information will be passed by the timing system interface. 32 Local Monitoring: The PDS may require network connections for local monitoring and debug- 33 ging. These are the responsibility of the PDS. 34 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  70. Chapter 6: Photon Detection System 6–57 Software: There should be no software required for the PDS to DAQ interface. The definition of 1 the data format should provide the required information. 2 Interaction with other groups: Related interface documents describe the interface between 3 the CE and LBNF, DAQ and LBNF, DAQ and Photon and both DAQ and CE with Technical 4 Coordination. The cryostat penetrations including through-pipes, flanges, warm interface crates 5 and feedthroughs and associated power and cooling are described in the LBNF/PDS interface doc- 6 ument. The rack, computers, space in the CUC and associated power and cooling are described in 7 the LBNF/DAQ interface document. Any cables associated with photon system data or commu- 8 nications are described in the DAQ/Photon interface document. Any cable trays or conduits to 9 hold the DAQ/CE cables are described in the LBNF/Technical Coordination interface documents 10 and currently assumed to be the responsibility of Technical Coordination. 11 Integration: Various integration facilities are likely to be employed, including vertical slice tests 12 stands, PDS test stands, DAQ test stands and system integration/assembly sites. The DAQ con- 13 sortia will provide hardware and software for a âĂIJvertical slice testâĂİ The PDS consortia will 14 provide PDS emulators and PDS readout hardware for DAQ test stands. (The PDS emulator and 15 PDS readout hardware may be the same physical object with different configuration ). Responsi- 16 bility for supply and installation of DAQ/PDS cables in these tests will be defined by the time of 17 the DAQ TDR. 18 Installation: Responsibility for purchase of the DAQ/CE cables is assigned to the PDS. The 19 installation of the DAQ/CE cables is assigned to the PDS. 20 6.8.6 Calibration / Monitoring 21 sec:fdsp-pd-intfc-calib This subsection concentrates on the description of the interface between the SP-PDS and Cali- 22 bration/Monitoring Task Force (CTF), since there is are components of the system planned to be 23 installed with the HVS Cathode, and through Field Cage strips and File Cage ground plane. 24 Hardware: The SP-PDS has proposed the photon-detector gain and timing calibration system to 25 be also used for SP-PDS monitoring purposes during commissioning and experimental operation. A 26 pulsed UV-light system is proposed to cross-calibrate and monitor the DUNE-SP photon detectors. 27 The hardware consists of warm and cold components. By placing light sources and diffusers on the 28 cathode planes designed to illuminate the anode planes the photon detectors embedded in the anode 29 planes can be illuminated. Cold component (diffusers and fibers) interface with High-Voltage and 30 will be described in a separate interface document. Warm components include controlled pulsed- 31 UV source and warm optics. These warm components will interface CTF with Slow-Controls/DAQ 32 subsystems and will be described in corresponding documents. Optical feedthrough is the cryostat 33 interface. Hardware components will be designed and fabricated by SP-PDS. Other aspects of 34 hardware interfaces are described in the following. The CTF and PDS groups might share rack 35 spaces which needs to be coordinated between both groups. There wonâĂŹt be dedicated ports for 36 all calibration devices. Therefore, multi-purpose ports are planned to be shared between various 37 groups. CTF and SP-PDS will define ports for deployment. It is possible that SP-PDS might 38 use Detector Support Structure (DSS) ports or TPC signal ports for routing fibers. The CTF in 39 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  71. Chapter 6: Photon Detection System 6–58 coordination with other groups will provide a scheme for interlock mechanism of operating various 1 calibration devices (e.g. Laser, radioactive sources) that will not be damaging to the PDS. The 2 PDS has proposed the photon-detector gain and timing calibration system. The system will be used 3 for PDS monitoring purposes during commissioning and for standard experimental operation. A 4 pulsed UV-light system is proposed to cross-calibrate and monitor the DUNE-SP photon detectors. 5 The hardware consists of warm and cold components. By placing light sources with diffusers on 6 the cathode planes, the system is designed to illuminate the photon detectors embedded in the 7 anode planes. The details are described in the DUNE Interface Document: SP-PDS/CTF. Cold 8 components of the calibration system (diffusers and fibers) interface with the HVS. Diffusers are 9 installed at CPA, and therefore reside at the same CPA potential. Quartz fibers are insulators used 10 to transport light from optical feedthroughs (at the cryostat top) through Filed Cage ground plane, 11 and through Filed Cage strips to the CPA top frame. These fibers are then optically connected 12 to diffusers located at CPA panels. Required fiber resistance is defined by HVS requirements 13 to ensure the cathode is protected from shorting out due to fiber conductivity. PDS hardware 14 components will be designed and fabricated by PDS. 15 Firmware: The firmware will enable UV-light system to interface to DAQ/Slow-Controls to com- 16 municate start/stop of calibration run, and issue commands to define types (amplitude, timing, 17 frequency) of calibration pulses. Protocols will be defined with DAQ, but the firmware realization 18 and testing will be responsibility of SP-PDS. Timing and Synchronization: Clock and synchroniza- 19 tion messages will be propagated from the DAQ to the SP-PDS calibration unit using a backwards 20 compatible development of the ProtoDUNE Timing System protocol (See Dune docdb-1651). See 21 also SP-PDS to DAQ interface definition. 22 Software: The software interface between the groups consists of software needed to perform 23 calibrations of the photon detection system and any simulations of the detector needed to develop 24 calibration schemes. The calibration software which will analyze the photon detection input and 25 calculate calibration quantities will be the responsibility of the SP-PDS Consortium, with the 26 guidance of the CTF. The CTF will be responsible for defining the quantities to be measured. The 27 SP-PDS Consortium will be responsible for providing a simulation model to test the calibration 28 schemes. The CTF will provide the design and model of databases (DBs) to store the calibration 29 information and these DBs will be filled out by the SP-PDS Consortium. 30 Testing: Components of such system are being rested with ProtoDUNE. Additional tests will be 31 managed between SP-PDS and CTF if necessary, including a test stand with shared responsibility. 32 Integration: Various integration facilities are likely to be employed, including vertical slice tests 33 stands, cold electronics test stands, DAQ test stands and system integration/assembly sites. The 34 PDS consortia will provide firmware/software for PDS integration and operation and testing. 35 Components of such system are being rested with ProtoDUNE. Additional tests will be managed 36 between PDS and HVS if necessary, including a test stand with shared responsibility. HVS will 37 verify HV design and operation without discharges that could cause light emission observed by 38 PDS should this be a concern. 39 Various integration facilities are likely to be employed, including vertical slice tests Integration: 40 stands, cold electronics test stands, DAQ test stands and system integration/assembly sites. The 41 PDS consortia will provide support for PDS integration and operation. 42 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  72. Chapter 6: Photon Detection System 6–59 Installation: Responsibility for fabrication/installation of PDS Calibration components is as- 1 signed to PDS. Responsibility for fabrication/installation of PDS Calibration components is as- 2 signed to PDS. 3 Commissioning: PDS-SP will provide staffing for commissioning of SP-PDS calibration system 4 in the cryostat. Cold PDS-SP components need be installed with Cathode-Plane assemblies and 5 Field Cage arrays, and possible with DSS. Warm SP-PDS calibration components may be installed 6 at the end and tested with DAQ. Calibration scope and goals will be further defined within CTF. 7 PDS will provide staffing for commissioning of PDS calibration system in the cryostat. 8 6.9 Installation, Integration, and Commissioning 9 6.9.1 Transport and Handling 10 Following assembly and testing of the PD modules they need to be carefully packaged and shipped 11 to the far detector site for checkout and any final testing prior to installation into the cryostat. 12 Handling and shipping procedures will depend on the environmental requirements determined for 13 the photon detectors. 14 • Development of a testing plan to determine environmental requirements for photon detector 15 handling and shipping. The environmental conditions apply for both surface and under- 16 ground transport, storage and handling. Requirements for light (UV filtered areas), temper- 17 ature, and humidity exposure should be developed. 18 • Handling procedures need to be developed to ensure environmental requirements are met. 19 This should include handling at all stages of component and system production and assembly, 20 testing, shipping, and storage. It is likely that PD modules and components will be stored for 21 periods of time during production and prior to installation into the FD cryostats. Appropriate 22 storage facilities need to be constructed at locations where storage will take place. 23 • Shipping and storage containers need to be designed and produced. Given the large number 24 of photon detector modules to be installed in the FD, it will be advantageous to develop 25 shipping containers that can be re-used. 26 • Documentation and tracking of all components and PD modules will be required during 27 the full production and installation schedule. Well defined procedures need to be in place 28 to ensure that all components/modules are tested and examined prior to, and after, ship- 29 ping. Information coming from such testing and examinations will be stored in a hardware 30 database. 31 • It is expected that photon detector will be assembled at more than one location and that 32 components will come from a number of other locations. Oversight of the shipping and 33 handling procedures will be critical. This responsibility should fall to a single institution and 34 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  73. Chapter 6: Photon Detection System 6–60 manager. 1 • Integration and Test Facility (ITF) Operations: 2 – Transportation to and from ITF should be planned. The PDS units will be shipped 3 from the production area in quantities compatible with the APA transport rates. 4 – Operations: The PDS deliveries will be stored in temperature and humidity controlled 5 storage area. Their mechanical status will be inspected. 6 • Transportation to SURF: The delivery to SURF will be such that the storage time before 7 integration will be at most two weeks. 8 6.9.2 Integration with APA 9 • Integration: 10 If the PDS detectors can be installed after the wire winding is completed, as in the present 11 baseline design, their integration on the APA frame will happen at the Integration facility. 12 Experts from both groups will work with the installation team. An electrical test with 13 APA/PDS/CE will be performed at the integration facility in a cold box, after the integration 14 of PDS and CE on the APA frame has been completed. 15 • Installation: 16 The APA consortium will be responsible for the transportation of the integrated APA frames 17 from the integration facility to the LBNF/SURF facility. The UIT team, under supervision 18 of the APA group, will be responsible to move the equipment into the clean room. Work on 19 the 2-APA connection and inspection in the toaster is performed by the APA group. Work 20 on cabling in the toaster is performed by PDS and CE groups under supervision of the APA 21 group. Once the APAs will be moved inside the cryostat, the PDS and CE consortia will be 22 responsible for the routing of the cables in the trays hanging from the top of the cryostat. 23 6.9.3 Installation into Cryostat / Cabling 24 6.9.4 Calibration and Monitoring 25 The calibration and monitoring systems for the photon detector system will interface with several 26 groups within the DUNE FD project, including the calibration group, slow controls group, and 27 data acquisition group. 28 • The number of penetrations required for the calibration and monitoring systems need to be 29 determined so that the cryostat design, including feedthroughs can be finalized. 30 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  74. Chapter 6: Photon Detection System 6–61 • Mounting requirements for the calibration system inside the cryostat need to be determined. 1 Any light delivery hardware to be mounted on the cathode plane assemblies will need to 2 be developed in coordination with the CPA group. A plan for fiber routing will need to be 3 made. Cable routing and power distribution plans for both the calibration and monitoring 4 • Readout of both the calibration and monitoring systems will need to be developed with the 5 DAQ and slow controls groups. Mappings of the systems will need to be reflected in the PD 6 hardware database. 7 • Any calibration systems utilizing radioactive sources will need to be developed in coordination 8 with the radiopurity and physics groups. It is important to ensure in addition, that any 9 components of such a system do not contaminate the LAr or compromise the electron lifetime. 10 6.10 Installation, Integration and Commissioning 11 sec:fdsp-pd-install Content: Kemp 12 (Length: TDR=30 pages, TP=6 pages) 13 6.10.1 Transport and Handling (1 page) 14 sec:fdsp-pd-install-transport 6.10.2 Integration with APA (2 pages) 15 sec:fdsp-pd-install-pd-apa 6.10.3 Installation into cryostat/cabling (1 pages) 16 sec:fdsp-pd-install-pd-cryo 6.10.4 Calibration/Monitoring (1 pages) 17 sec:fdsp-pd-install-calib 6.11 Quality Control 18 sec:fdsp-pd-qc Content: Warner 19 (Length: TDR=10 pages, TP=2 pages) 20 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  75. Chapter 6: Photon Detection System 6–62 6.11.1 Production and Assembly (Local) 1 sec:fdsp-pd-qc-local 6.11.2 Post-factory Installation (Remote) 2 sec:fdsp-pd-qc-remote 6.12 Safety 3 sec:fdsp-pd-safety Content: Warner 4 (Length: TDR=5 pages, TP=1 pages) 5 6.13 Organization 6 sec:fdsp-pd-org Content: Segreto/Warner/Mualem 7 (Length: TDR=20 pages, TP=4 pages) 8 6.13.1 Single-Phase Photon Detection System Consortium Organization 9 sec:fdsp-pd-org-consortium Content: Segreto 10 6.13.2 Planning Assumptions 11 sec:fdsp-pd-org-assmp Content: Segreto/Warner 12 6.13.3 WBS and Responsibilities 13 sec:fdsp-pd-org-wbs Content: Warner/Mualem 14 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  76. Chapter 6: Photon Detection System 6–63 6.13.4 High-level Cost and Schedule 1 sec:fdsp-pd-org-cs Content: Warner/Mualem 2 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  77. Chapter 7: Data Acquisition System 7–64 Chapter 7 1 Data Acquisition System 2 ch:fdsp-daq 7.1 Data Acquisition System (DAQ) Overview (Georgia Kara- 3 giorgi & David Newbold) 4 sec:fdsp-daq-ov 2 Pages - largely generic but some highlighting of SP-specifics. 5 7.1.1 Introduction 6 sec:fdsp-daq-intro fig:daq-overview The overall DUNE Far Detector Data Acquisition System (DAQ) is illustrated in Fig. 7.1. 7 Describe figure here. 8 fig:daq-overview Figure. 7.1 illustrates the data flow and the exchange of trigger and monitoring messages. 9 7.1.2 Design Considerations 10 sec:fdsp-daq-des-consid Include: Raw data rate from WIBs, Josh’s table of data volumes for each event type and the 30 PB/year offline limit. Space and thermal power limits. Note, this table may be better put sec:fdsp-daq-design into Section 7.2 to make this section more generic. 11 The Data Acquisition System design must enable... ... 12 Anne suggests: Within this section add ref to requirements document when it’s ready, and maybe list the most important half dozen in a table here). E.g., 13 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  78. Chapter 7: Data Acquisition System 7–65 DUNE FD DAQ Global Trigger Logic DAQ Module #N Back-End Computing Module Trigger trigger commands Event Output Logic L0 triggers Builder Farm Disk Buffer primitives Front-End Front-End Computing Readout Detector Module #N RAM Data Electronics Data Data Electronics Buffer Selector Readout HW Receiver Figure 7.1: A generalized overview of high-level far detector DAQ components showing one out of the four detector modules. The electronics digitizes the detector signals and send the data to the DAQ Front-End Readout Hardware. This component forms L0 Trigger Primitives and sends them and the data to a Front-End Computing Data Receiver. The receiver sends the data to a RAM of sufficient size to buffer it longer than typical worse case trigger latency. The L0 Trigger Primitives are forward to the Module Trigger Logic (MTL) unit which services the entire detector module. The MTL forwards to the Global Trigger Logic unit which services the entire DUNE Far Detector. Trigger commands are then sent back down and to the Event Builder Farm which, based on the trigger command information, queries the appropriate Front-End Computing units which return the requested data. The Event Builder then aggregates the data and writes it to the Output Disk Buffer. Each 10 kt module has specific differing details which are described below. fig:daq-overview Table 7.1: Important requirements on the DAQ system design Requirement ... pdphysicsparams 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  79. Chapter 7: Data Acquisition System 7–66 By the end of the volume, for every requirement listed in this section, there should exist an explanation of how it will be satisfied. 1 7.1.3 Scope 2 sec:fdsp-daq-scope fig:daq-overview This section may also wish to refer to Fig. 7.1. 3 The scope of the Data Acquisition System includes the continued procurement of materials for, 4 and the fabrication, testing, delivery and installation of the following systems: 5 Whatever the items are... 6 • Readout electronics 7 • 8 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  80. Chapter 7: Data Acquisition System 7–67 7.2 DAQ Design 1 sec:fdsp-daq-design 16 Pages 2 7.2.1 Overview (Giles Barr) 3 sec:fdsp-daq-ltr The DAQ Design has been driven by finding a cost effective solution that satisfies the requirements. 4 Seveal design choices have nevertheless been made. From a hardware perspecive, the DAQ design 5 follows a standard HEP experiment design, with customised hardware at the upstream, feeding 6 and funnelling (merging) and moving the data into comupters. Once the data and triggering 7 information are in computers, a considerable degree of flexibility is available and the processing 8 proceeds with a pipelined sequence of software operations, involving both parallel processing on 9 multi-core computers and switched networks. The flexibility allows the procurement of computers 10 and networking to be done late in the delivery cycle of the DUNE detectors, to benefit from 11 increased capability of commercial devices and falling prices. 12 Since DUNE will operate over a number of decades, the DAQ has been designed with upgradability 13 in mind. With the fall in cost of serial links, a guiding principle is to include enough output 14 bandwidth to allow all the data to be passed downstream of the custom hardware. This allows 15 the possibility for a future very-fast farm of comuting elements to accomodate new ideas in how 16 to collect the DUNE data. The high output bandwidth also gives a risk mitigation path in case 17 the noise levels in a part of the detector are higher than specified and higher than tolerable by 18 the baseline trigger decision mechanism; it will allow aditional data processing to be added (at 19 additional cost). 20 The data collection will incorporate the data from single-phase and dual-phase TPCs and also single 21 and dual-phase versions of the photon-detector readout system. These are viewed as essentially 22 four types of sub-detectors within the DAQ and will follow the same overall data collection scheme 23 as shown in figure 1. The readout is arranged in a hierarchical manner to allow localised trigger 24 decisions to be made at the APA level, and then the cavern level before being combined over the 25 full four caverns. ch initial trigger decisions. The control of the detector elements will allow a fault 26 in one part to not halt data taking in another part, certainly at the per-cavern level, but maybe 27 also at more local levels. This will prevent a supernova burst following a failure in some part of a 28 cavern from being missed. 29 [The folowing text will need considerable revision to make sure it corresponds with whatever ends 30 up as figure 1, but the text here gives an idea that the overview will be a very quick visit of 31 everything, and all the detail is in the later sections. Terms in boldface are temporary madeup 32 things and must be replaced by the officially decided names]. 33 It is helpful, on first looking at the DUNE DAQ dataflow scheme, to consider how the main data is 34 collected first and then to look at how the triggering and synchronisation functions are included; 35 we take this approach in this overview. The main data are initially merged within one APA and 36 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  81. Chapter 7: Data Acquisition System 7–68 placed in a primary buffer to allow triggering decisions to be made. When a trigger decision is 1 made, all the data in a time window and in a designated region of interest (ROI) around the trigger 2 is extracted from the buffer and sent for event building, a second buffer area and possible transfer 3 to permanent storage at Fermilab. This covers trigger decisions for beam, calibation, atmospheric 4 neutrino, cosmic ray events, individual supernova neutrinos and also candidates for searches such 5 as proton decays, or low energy events such as solar and diffuse supernova neutrinos. Additionally, 6 when a supernova burst is detected internally within DUNE, a further SSD buffer will be used 7 to store all the data for all APAs for a long period. The primary buffer must be long enough for 8 trigger decision latency (including the time for enough supernova events in a burst to arrive and 9 appear over the background). Further details of the buffering scheme is described in section 7.2.2. 10 (Triggering Overview) In parallel with the data buffering scheme described above, summaries 11 of detected hits trigger primitives are assembled at the APA level to detect clusters of hits and 12 apply algorithms to distingush them from background (either radioactive decays or detector noise). 13 This is described in detail in section 7.2.3. Whether this process is more suitable for FPGAs 14 or computers is under study, as it depends on the interfaces, both can be accomodated in the 15 architecture, and both have been costed (neither yet!). To retain the APA-level modulariy, the 16 trigger primitives are collected and processed in the same APA node that buffers the data. The 17 trigger primitives are then sent to the cavern level and then the detector-level triggers to allow 18 both multi-APA triggers to be formed and also allow the supernova burst detection decisions to be 19 made to initate data transfer to SSDs. This is described in detail in section 7.2.5. When a trigger 20 decision is formed, instructions are sent to the primary buffers to retrieve the full data, build 21 them into events and store the results in the secondary buffers . The events for the main physics 22 analyses will be retained for offline study at this point in the DAQ. A software trigger algorithm 23 could be run at this point to eliminate obvious noise-source events (such as pickup on a row of 24 wires), especially if numerous. A further feature, useful for certain supernova studies will be to let 25 a sample of below-threshold events through to the secondary buffers where they are retained for a 26 few hours. If a SNEWS external warning of supernova is subsequently received, these events can 27 be kept permanently if desired, to allow lower thresholds during a SNEWS period than normal. 28 (Synchronisation Overview) Unknown until the interface with elecronics is known 29 7.2.2 Local Readout & Buffering (Giles Barr & Giovanna Miotto & Brett 30 Viren) 31 sec:fdsp-daq-ltr Describe how the data is received from the detector electronics, and buffered while awaiting a trigger decision, together with any processing that affects stored data. The starting point is data incoming from the WIBs and the end point is corresponding data sitting in memory ready for event building. 32 fig:daq-readout-buffering-baseline Figure 7.2 illustrates the local readout and buffering data flow in the context of a single APA. 33 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  82. Chapter 7: Data Acquisition System 7–69 Cold Electronics APA 2 [1] [2] WIB3 connectors [3] Single-Phase Module DAQ [4] Single-Phase Module DAQ Components for two APAs [1] Front-End Readout [2] WIB1 for two APAs connectors [3] ACTA COB 2 [4] RCE1 [1] FPGA [2] WIB2 SSD connectors [3] [4] RCE2 FPGA [1] SSD [2] WIB4 connectors [3] RCE3 [4] FPGA SSD [1] [2] WIB5 RCE4 connectors [3] FPGA [4] SSD APA 1 ACTA COB 1 [1] RCE1 Front-End Computing for two APAs [2] WIB1 FPGA connectors [3] SSD FELIX Host Computer [4] FELIX RCE2 PCIe board RAM [1] FPGA Buffer Data Selector [2] WIB2 SSD connectors [3] [4] RCE3 FPGA [1] SSD [2] L0 trigger WIB4 primitives connectors [3] RCE4 FPGA [4] SSD [1] [2] WIB5 Single-Phase Module Back-end Computing connectors [3] SNB-dump trigger commands [4] Module Nominal trigger commands Event Builder Trigger Logic Offline Disk Buffer [1] SNB dump Event Builder [2] WIB3 connectors [3] [4] Single-Phase Module -- two APAs Figure 7.2: Illustration of data flow for two out of 150 APAs in the Single-Phase module. It shows the Cold Electronics WIB-RCE connections which send one half of one APA face to each RCE. The data and L0 trigger primitives the RCEs are received by a single FELIX host. The data is buffered into RAM and the trigger primitives are sent to the Module Trigger Logic unit (MTL) and sent to the Global Trigger Logic unit (not shown). Nominal (non-dump) trigger commands are delivered to the Event Builder which polls the selector on the appropriate FELIX host for the requested data. The MTL sends special SNB-dump trigger commands directly to the Front-End Readout hardware so that it may initiate a full-stream dump to local storage. This dump is then sent out over Ethernet to a special SNB Event builder. Both types of event builders finally save triggered data to file on the offline buffer disk. fig:daq-readout-buffering-baseline 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  83. Chapter 7: Data Acquisition System 7–70 7.2.3 Local Trigger Primitive Generation (Josh Klein & J.J. Russel & Brett 1 Viren & DP Expert?) 2 sec:fdsp-daq-ltr Below are from slides bv may show at the Jan WS. Content copied here and now as a starting point. 3 The TPC data is used to generate trigger primitive messages (TPM) local to each APA and 4 which summarize the activity recently sensed by their connected conductors. These TPMs are 5 emited from each APA DAQ Front End and become fodder for later determining trigger command 6 sec:fdsp-daq-sel messages (TCM) as described in Section 7.2.5. 7 Only the 480 collection channels associated with each APA face are used for forming TCMs. 8 Reasons for this reduction include the fact that collection channels: 9 • have higher signal to noise ratio compared to induction channels. 10 • fully and independently are sensitive to each APA face. 11 • have unipolar signals that directly give an approximate measure of ionization charge without 12 costly field response deconvolution computation. 13 • can be divided into smaller groups defined by natural hardware boundaries for parallel pro- 14 cessing. 15 fig:daq-overview Figure 7.1 illustrates the connectivity between the four connectors on each of the five WIBs and 16 the DAQ APA Front End. The data is received from 80 1 Gbps fiber optical links by four Recon- 17 figurable Computing Elements (RCE) in the ACTA Cluster On Board (COB) system. 18 Matt: help! Each RCE consists of a .... 19 The pattern of connectivity between WIBs and RCEs results in the data from the collection 20 channels covering one half of one APA face being received by each RCE. Each RCE has two 21 sec:fdsp-daq-hlt primary functions. The first is transmission of all data as described in Section 7.2.4. The second 22 is to produce TPMs from its portion of the collection channel data. 23 The TPMs are produced from a trigger primitive production pipeline of algorithms. These algo- 24 rithms still require development but can be broadly described. 25 1. On a per channel basis calculate a rolling baseline and RMS that characterizes recent samples 26 minimal influence from ionization signal. 27 2. Locate contiguous ADC samples that go above a threshold which is defined in terms of the 28 baseline and RMS. 29 3. Emit their time bounds and total charge as a ROI ch TPM. 30 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  84. Chapter 7: Data Acquisition System 7–71 These ROI ch TPM represent some possible activity occurring somewhere in the LAr within a 1 ± 2.5 mm strip that extends in time by the ROI time bounds. Depending on the threshold set, 2 these TPMs may be numerous due to 39 Ar decays and noise fluctuations. Further processing must 3 be done with more global information. This may be done as part of the Module Trigger Logic 4 sec:fdsp-daq-sel (MTL) as described in Section 7.2.5 or it may be done immediately in the RCE pipeline. Strategies 5 to summarize these detailed TPM into fewer TPMs include: 6 1. Pad each ROI ch in a channel by a fixed amount in order to anticipate their use later as defining 7 readout (eg, long enough to account for inter-plane drift times (6.25 µs) and induction signal 8 extents ( ∼ 100 µs). 9 2. Form the union of ROI across all channels observed by a given RCE. 10 3. Merge subsequent ROI which are separated by some small time interval. 11 If the Single-Phase detector module generates excess noise, such as that from RF emission picked 12 up coherently across some group of channel, it must be mitigated at the start of the pipeline 13 and will likely require additional computational resources. Some ideas to respond to this scenario 14 include.... 15 Ideas? 16 . 17 7.2.4 Dataflow, Trigger and Event Builder (Giles Barr & Josh Klein & Gio- 18 vanna Miotto & Kurt Biery & Brett Viren) 19 sec:fdsp-daq-hlt Describe the dataflow infrastructure . This should cover transport of data and trigger informa- tion, infrastructure for generating local and global trigger commands (but not their algorithms, that’s next), as well as what happens to the data once a trigger is generated (ie. event build- fig:daq-readout-buffering-baseline ing). Figure 7.2 may be referenced 20 The data volume that is flowing around the DUNE DAQ is considerable, over 10TB/s conntin- 21 uoiusly. However, the control of it is simplified by making the modularity of the primary buffer at 22 the APA level. The majority of the data corresponds to the untriggered parts and never leaves the 23 nodes that house the primary buffers. The parts that do exit in one of three circumstances, (a) 24 as selectd event data (b) as trigger primitives, to be considered on the cavern-wide decision step 25 or (c) as previously triggered supernova burst data being ’trickled out’ from the SSD storage. All 26 thee of these transfers lives entirely in the software domain of a commodity computer farm and so 27 a variety of techniques can be considered for each; in this description, we consider each of them as 28 a data-pull protocol, similar to that in use at ProtoDUNE. 29 artDAQ is a modern, general-purpose framework, that has been used in DUNE prototype tests 30 and elsewhere [refs]. It is optimised further than other frameworks to expliot the paralelism that 31 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  85. Chapter 7: Data Acquisition System 7–72 is possible with modern multi-core machines. It is the principle architecture that will be used 1 in DUNE. The authors of artDAQ have accomodated DUNE-specific feature-addition requests, 2 an a number of libraries have been used by linking into the ’boardreader’ parts of artDAQ (the 3 parts that handle the incloming data from the data sources), and it is likely that future DUNE 4 extensions will be by one of these two routes. 5 (Section on FELIX data ingress, error handling, synchronisation, ring-buffer expiry). As noted 6 above, one of the complex data flow control tasks is managing the data asit enters the primary 7 buffers on the per-APA nodes . Data throughput on these nodes is governed by the use of the 8 PCIe and memory busses, and so the softwre will be written to mimumize data-copies on the input 9 side of the primary buffer . During normal operation, there must be sufficient ’headroom’ to allow 10 an additional write of data to SSDs during the supernova burst. The current model for dataflow 11 control is tht each APA will operate autonomously, data being written directly from hardware into 12 physical memory and not moved. The softare will keep track of the free and in-use memory (one 13 way is with a ring for each data source) and will maintain an index of the data. One strategy that 14 decentralises the error handling is for the writing to the primary buffer to not cause error handling 15 events, but for it to flag areas of the data for which problems exist only if/when it is to be read 16 again. Similarly to avoid memory alloction error handling, the incoming data can overwrite the 17 older data and read requests for data that has been overwritten will report the error. It is planned 18 to prototype the data transfers for the TDR. 19 (Section on (a) event building) Requsts for event building (i.e. reading data for succesful triggers 20 from the primary buffers will be donw using mostly standard features that are now in artDAQ. An 21 event-builder node is allocated for each trigger to be read. This event builder then requests portions 22 of data from the primary buffers for the data from that event (this read must be initiated by the 23 request, a difference with the current ProtoDUNE). If the data is missing (either due to errors 24 when it was first received, or because the request arrived so late, that the data were overwritten), 25 the request proceeds, but with flags set in the event header which are displayed on the operators 26 console. 27 (Section on (b) trigger farming) The per-APA-node will receive, or generate the trigger primitives 28 that summarise the hits from each APA, organised in blocks of time. In some circumstances, this 29 is sufficient to declare a trigger, in others, the hit pattern must be combined between APAs to 30 make the trigger decision. The list of APA-level decisions and the trigger primitives are assembled 31 into a block for each time block. Our default scheme for the dataflow is to use a similar method to 32 PotoDUNE, however several others are under study. In the ProtoDUNE method, a trigger farm 33 node is assigned to each time block and requests the trigger data block for it. When it receives 34 the data from all the APAs, it builds an event (using artDAQ funcions), and then processes it, to 35 assign the trigger decisions. One alternative (to avoid the possibility that too many small blocks of 36 data must arrive in one place at a time) is to split the cavern into regions, and have an intermediate 37 layer of data collecton. Another solution is to use data-push, since, it is likely that a single node 38 with a lot of cores can deal with all the trigger processing. 39 (Section on (c) SNB trickling) Because of the ling-term storage capabilities of the SSD drives, 40 there is no hurry to colect the data from them for a supernova. This task can therefore be done in 41 the background (indeed, it should be halted during a subsequent SNB trigger, to avoid increasing 42 the data transfers in the per-APA node). It is anticipated that a spernova collecor node will use 43 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  86. Chapter 7: Data Acquisition System 7–73 data-pull requests to slowly collect the data from each node and merge it in some way for offline 1 analysis. Probably there will be one data file per APA node which will be collected together in a 2 directory; presumably the offline will not want a single 10TB long file. 3 7.2.5 Data Selection Algorithms (Josh Klein & Brett Viren) 4 sec:fdsp-daq-sel Data Selection will follow a hierarchical design, beginning with local, APA Level trigger candidates, 5 Module (10 ktonne) Level triggers, and Global (Detector-wide) triggers. A high-level trigger (HLT) 6 may also be active within the Module Level trigger. The hierarchical approach is both natural 7 from a design standpoint, as well as allowing for vertical slice testing and partitioning during 8 commissioning of the system. 9 As discussed above, trigger primitives will be generated in the RCEs from the data stream for 10 each collection wires. The trigger primitives will be summary information for each collection wire, 11 such as the time of any threshold-crossing pulse, its integral charge, and time over threshold. A 12 collection wire with a non-null trigger primitive is said to be “hit.” These trigger primitives are then 13 passed, along with the full data stream, to the FELIX boards and their hosts, each of which handles 14 channels from a small number of APAs (likely two). An APA Level trigger candidate is passed 15 upward to a Module Level trigger, which arbirtrates between various trigger types, determining 16 whether a given APA Level trigger candidate is a valid Module Trigger and whether there are other 17 triggers that have a higher priority in any given slice of time. At this level, a more sophisticated 18 high-level trigger (HLT) may also be employed, which will allow a reduction in trigger rate from 19 various backrounds, including instrumental backgrounds, if needed. 20 A valid Module Level single-interaction trigger sends trigger commands back to the FELIX hosts 21 telling them which slice of time should be saved under the particular trigger header. At the start 22 of DUNE data taking, it is anticipated that for any given single-interaction trigger (a cosmic ray 23 track, for example) waveforms for all wires will be recorded for a full 5.4 ms “readout window.” 24 Such an approach is clearly very conservative, but it ensures that associated low-energy physics 25 (such as neutron captures from neutrons produced by neutrino interactions or cosmic rays) will 26 be recorded without any need to fine-tune APA-level triggering, and will not depend on the noise 27 environment across the APAs. In addition, the 5.4 ms readout window ensures that regardless of 28 when a given even causes a trigger, the entire track is recorded. We anticipate, however, that as 29 we gain experience running DUNE the overall data volume will reduced by writing out data from 30 only a subset of APAs for any given track, and possibly reducing the size of the readout window. 31 Other trigger streams—calibrations, random triggers, and prescales of various trigger thresholds, 32 will also be generated at the Module Level, and filtering and compression can be applied based upon 33 the trigger stream. For example, a large fraction of random triggers may have their waveforms 34 zero-suppressed, reducing the data volume substantially, as the dominant data source for these 35 will be 39 Ar events. Additional signal-processing can also be done on particular trigger streams if 36 needed and if the processing is available, such as fast analyses of calibration data. 37 At the Module Level, a decision can also be made on whether a series of interactions are consistent 38 with a supernova burst. If the number of APA Level low-energy trigger candidates exceeds a 39 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  87. Chapter 7: Data Acquisition System 7–74 threshold for the number of such events in a given time, a trigger command is sent from the 1 Module Level back to the RCEs, which store up to 10 seconds of unsuppressed, full waveform 2 data. That full waveform is then written out as a separate trigger stream for fast analysis by the 3 supernova working group, perhaps as an automated process. In addition, the Module Level passes 4 information about APA Level trigger candidates up to a detector-wide Global Trigger, which can 5 decide whether, integrated across all modules, enough APAs have detected interactions to qualify 6 for a supernova burst even if within a particular module the threshold is not exceeded. Trigger 7 commands from the Global Trigger Level are passed downward to RCEs in the same way as any 8 Module Level supernova burst trigger would be; at the Module Level, a Global Trigger looks like 9 just one more “external” trigger input. 10 APA Level trigger candidates will be generated within each FELIX host. The trigger decision will 11 be based on the number of adjacent wires hit in a given APA within a narrow time window (roughly 12 100 µ s), the total charge on these adjacent wires (or any wire with a non-null trigger primitive), 13 and possibly the time-over-threshold for collection wires with hits. Our studies show that even 14 for low-energy events (roughly 10-20 MeV) the reduction in radiological backgrounds is extremely 15 high with such criteria. The highest-rate background, 39 Ar, which has a decay rate of 10 MBq 16 within a 10 ktonne volume of argon, has an endpoint of 500 keV and requires significant pileup 17 in both space and time to get near a 10 MeV threshold. Other important background sources are 18 42 Ar, which has a 3.5 MeV endpoint and a decay rate of 1 kBq, and 222 Rn which has a decay rate 19 of XXXX and decays via a highly-quenched α of 5.5 MeV. The radon decays to 218 Po which a few 20 minutes later leads to a quenched α of 6 MeV, and ultimately a 214 Bi daughter (many minutes 21 later) which has a β decay with endpoint near 3.5 MeV. The α ranges are short and will hit at 22 most a few collection wires, but the charge deposit can be large, and therefore the charge threshold 23 will have to be well above the α deposits plus any pileup from 39 Ar and noise. 24 At the APA Level, two kinds of local trigger candidates can be generated. One is a “high-energy” 25 trigger, that indicates that within a given APA a candidate event with energy more than 10 26 MeV has been found. The thresholds in hit wires, total charge, and time-over-threshold, will be 27 optimized for at least 50% efficiency at this threshold, with efficiency increasing to 100% via a 28 turn-on curve that ensures at least 90% efficiency at 20 MeV. A second APA Level trigger candiate 29 will be generated for low-energy events, between 5 MeV and 10 MeV. These low-energy APA 30 trigger candidates will not by themselves generate valid Module Level triggers, but rather be used 31 at the Module Level to determine whether a burst of events across many APAs is consistent with 32 a supernova. 33 The Module Level takes as input both APA Level trigger candidates (both low-energy and high- 34 energy), as well as external trigger candidate sources, such as the Global (detector-wide) trigger, 35 external triggers such as SNEWS, and information about the time of a Fermilab Beam spill. The 36 Module Level will also generate internal triggers, such as random triggers and calibration triggers 37 (for example, telling a laser system to fire at a prescribed time). In addition, at the Module Level 38 prescales of all trigger types that normally would not generate a Module Level will be made. For 39 example, a single low-energy trigger does not cause a Module Level trigger on its own, but at some 40 large prescale fraction it could be accepted. 41 The Module Level is responsible also for checking candidate triggers against the current Run 42 Control trigger mask: in some runs, for example, we may decide that only random triggers are 43 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  88. Chapter 7: Data Acquisition System 7–75 accepted, or that certain APA trigger candidates should not be accepted because those APAs are 1 noisy or misbehaving in some way. In addition, the Module Level will count low-energy trigger 2 candidates from the APAs and, based upon the number and distribution of those triggers in a long 3 time interval (e.g., 10 seconds), decide to generate a supernova burst trigger command. The trigger 4 logic for a supernova burst will be optimized to accept at least 90% of all Milky Way supernovae, 5 and our studies of simple low-energy trigger criteria show that we can likely do much better than 6 that. 7 The HLT can also be applied at this level, particularly if there are unexpectedly higher rates 8 from instrumental or low-energy backgrounds, that require some level of reconstruction or pattern 9 recognition. An HLT might also allow for efficency triggering on lower-energy single interactions, 10 or allow for better sensitivity for supernovae beyond the Milky Way, by employing a weighting 11 scheme to individual APA Level trigger candidates—higher-energy trigger candidates receiving 12 higher weights. Thus, for example, two APA Level trigger candidates consistent with 10 MeV 13 interactions in 10 seconds might be enough to create a supernova burst candidate trigger, while 14 100 5 MeV APA Level trigger candiates in 10 seconds might not. Lastly, the HLT can allow for 15 dynamic thresholding; for example, if a trigger appears to be a cosmic-ray muon, the threshold for 16 single interactions can be lowered (and possibly prescaled) for a short time after that to identify 17 spallation products. In addition, the HLT could allow for a dynamic threshold after a supernova 18 burst, to extend sensitivity beyond the 10 s readout buffer, while not increasing the data volume 19 associated with supernova burst candidates linearly. 20 All low-energy trigger candidates are also passed upwards to the Global trigger level, which can 21 integrate the APA level trigger across all 10 ktonne modules and determine if enough APAs have 22 trigger candidates that a supernova burst may be occuring. This approach increases the sensitivity 23 to trigger bursts by a factor of four (for 40 ktonnes), thus extending the burst sensitivity to a 24 distance twice as far as for a single 10 ktonne module. 25 The Module Level is also responsible for creating a trigger header that includes a global timestamp 26 for the trigger, and information on what type of trigger was created. A log of all APA Level trigger 27 candidates will also be kept, whether or not they are part of a Module Trigger. A 28 s described above, for any high-energy APA Level trigger candidate, a Module Level trigger com- 29 mand is sent to all FELIX hosts instructing them to save a 5.4 ms readout window will written for 30 all wires across all APAs (providing the start and end times to the FELIX hosts). Thus, a DUNE 31 “event” is 5.4 ms of data from all wires in response to a Module Level trigger. The Module Level 32 trigger is also responsible for sending the trigger commands that tell the RCEs to dump their 10 33 s unsuppressed “supernova” buffer. If a supernova burst trigger is created at the Global trigger 34 level, a trigger command is passed back down to the Module Level, which then passes that on to 35 the RCEs for readout of the long (10 s) unsuppressed buffer, the same way it would if a supernova 36 burst is detected at the Module Level. 37 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  89. Chapter 7: Data Acquisition System 7–76 7.2.6 Timing & Synchronization (David Cussans & Kostas Manolopoulos) 1 sec:fdsp-daq-timing All components of the DUNE Single Phase detectors are synchronized to a common clock. In 2 order make full use of the information from the photon detection system the common clock must 3 be aligned within a single detector with an accuracy of O(1ns). In order to form a common trigger 4 for super novae between detector modules the timing between detectors must be aligned with an 5 accuracy of O(1ms). However, a tighter constraint is the need to calibrate the common clock 6 to universal time (derived from GPS) in order to adjust the data selection algorithm inside an 7 accelerator spill, which requires an absolute accuracy of O(1us). 8 Single and Dual phase detector modules use a different timing system, driven by the different 9 technical requirements and development history of the two systems. A single phase detector 10 module has many more timing end-points than a dual phase module and many of the end-points 11 are simpler than the end-points in the dual phase, for example a WIB vs. uTCA crate. Both 12 systems have been sucessfully prototyped. 13 The DUNE Single Phase detectors use a development of the protoDUNE timing system. Syn- 14 chronization messages are transmitted over a serial data stream with the clock embedded in the 15 fig:daq-readout-timing data. The format is described in DUNE DocDB-1651. Figure 7.3 shows the overall arrangement 16 of components within the Single Phase Timing System(SPTS). A stable master clock, disciplined 17 with a 10MHz reference is used in the SPTS. A one-pulse-per-second (1PPS) signal is also received 18 by the system and is time-stamped onto a counter clocked by the SPTS master clock, however the 19 periodic synchronization messages distributed to the Single Phase detectors are an exact number 20 of clock cycles apart even if there is jitter in the 1PPS signal. 21 The GPS signal is encoded onto optical fibre and transmitted to the CUC, where it is converted 22 back to an RF signal on coaxial cable and used as the input to a GPS displined oscillator. The 23 oscillator module also houses a IEEE 1588 (PTP) Grand Master and an NTP server. The PTP 24 Grand Master provides a timing signal for the Dual Phase White Rabbit timing network. The 25 NTP server provides an absolute time for the 1PPS signal. The SPTS relates its time counter onto 26 GPS time by timestamping the 1PPS signal onto the SPTS time counter and reading the time in 27 software from the NTP server. 28 The latency from the GPS antenna on the surface to the GPS receiver in the CUC will be measured 29 by optical time domain reflectometry at installation. Given the modest absolute time accuracy 30 required (sufficient to select data within an accelerator spill) dynamic monitoring of this delay is 31 not required. 32 The White Rabbit synchronization signals from the Dual Phase are time-stamped onto the SPTS 33 clock domain and the SPTS synchronization signals are time stamped onto the Dual Phase clock 34 domain. This allows the timing in the Single Phase and Dual Phase detectors to be aligned. A 35 similar scheme is used to relate the Single Phase protoDUNE Single Phase timing domain to be 36 related to the beam instrumentation White Rabbit time domain. 37 In order to provide redundancy, and also the ability to easily detect issues with the timing path, 38 two independent GPS systems are used. One with an antenna at the head of the Yates shaft, 39 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  90. Chapter 7: Data Acquisition System 7–77 the other with an antenna at the head of the Ross shaft. The two independent timing paths are 1 brought together in the same rack in the CUC. Using 1:2 fibre splitters one SPTS unit can be 2 left as a hot-spare while the other is active. This also allows testing of new firmware and software 3 during comissioning without the risk of loosing the SPTS if a bug is introduced. 4 Figure 7.3: Illustration of the components in the DUNE Timing System. fig:daq-readout-timing All the custom electronic components for the SPTS are contained in two Micro-TCA shelves. At 5 any one time one is active and the other is a hot-spare. The 10MHz reference clock and the 1PPS 6 signal are received by a single width AMC at the centre of the Micro-TCA shelf. This master 7 timing AMC produces the SPTS signals and encodes them onto a serial data stream. This serial 8 datastream is distributed over a standard star-point backplane to the fanout AMCs which each 9 drive the signal onto up to 13 SFP cages. The SFP cages are either occupied by 1000Base-BX 10 SFPs, each of which connects to a fibre running to an APA, or to a Direct Attach cable which 11 connects to systems elsewhere in the CUC, i.e. the RCE crates and the data selection system. 12 fig:daq-readout-sp-timing This arrangement is shown in figure 7.4 13 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  91. Chapter 7: Data Acquisition System 7–78 Figure 7.4: Illustration of the components in the Single Phase Timing System. fig:daq-readout-sp-timing 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  92. Chapter 7: Data Acquisition System 7–79 Beam timing 1 The neutrino beam is produced at the Fermilab accelerator complex in spills of 10 µ s duration. A 2 spill location system (SLS) at the far detector site will locate the time periods in the data when 3 beam could be present, based on network packets received from Fermilab containing preductions 4 of the GPS-time of the spills. data, as it traverses the DAQ system, where beam intractions may 5 be present. Experience from MINOS and NOvA shows that this can provide beam triggering 6 with high reliability, although the system outlined here contains an extra layer of reduncancy in 7 this process. Several stages of narrowing down the window in which the beam arrives will be 8 done, aiming for an accuracy of better than 10% of a drift time, or 0.5ms at the time the data 9 are selected from the DAQ buffers. Ultimately, an offline database will match the actual time of 10 the spill with the data, thus removing any reliance on real-time network transfer for this crucial 11 stage of the oscillation measurements, the network transfer of spill-timing information is simply to 12 ensure a correctly located and sufficiently wide window of data is considered as beam data. This 13 system is not required, and is not designed to provide signals accurate enough to measure neutrino 14 time-of-flight. 15 The precision to which the spill time can be predicted at Fermilab improves as the acceleration 16 process of the protons producing the spill in question advances. The spills currently occur at 17 intervals of 1.3s; the system will be designed to work with any interval, and to be adaptable in 18 case the sequence described here changes. For redundancy, three packets will be sent to the far 19 detector for each spill. The first is approximately 1.6s before the spill-time, which is at the point 20 where a 15Hz booster cycle is selected; from this point on, there will be a fixed number of booster 21 cycles until the neutrinos and the time is subject to a few ms of jitter. The second is about 0.7s 22 before the spill, at the point where the main injector acceleration is no longer coupled to the 23 booster timing; this is governed by a crystal oscillator and so has a few µ s of jitter. The third 24 will be at the ‘$74’ which is just before the kicker fires to direct the protons at the LBNF target; 25 this doesn’t improve the timing at the far detector much, but serves as a cross check for missing 26 packets. This system is enhanced compared to that of MINOS/NOvA, which only use the third 27 of the above timing signals. The reason for the larger uncertainty in the time interval from 1.6s to 28 0.7s is that the booster cycle time is synchronised to the electricity supply company’s 60Hz which 29 has a variation of about 1%. 30 Arrival-time monitoring information from a year of MINOS data-taking was analysed, and it was 31 found that 97% of packets arrived within 100ms of being sent and 99.88% within 300ms. 32 The spill location system will therefore have estimators of the GPS-times of future spills, and 33 recent spills contained in the ring buffers. These estimators will improve in precision as more 34 packets arrive. The DAQ will use data in a wider window than usual, if, at the time the trigger 35 decision has to be made, the precision is less accurate due to missing or late packets. From the 36 MINOS monitoting analysis, this will be very rare. 37 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  93. Chapter 7: Data Acquisition System 7–80 7.2.7 Computing & Network Infrastructure (Kurt Biery & Babak Abi) 1 sec:fdsp-daq-infra Describes the infrastructure that will support the software components described above. 2 7.2.8 Run Control & Monitoring (Giovanna Miotto & Jingbo Wang 3 sec:fdsp-daq-tcm Describe how the system is controlled and monitored. 4 7.3 Interfaces (David Cussans & Matt Graham) 5 sec:fdsp-daq-intfc 5 Pages 6 fig:daq-overview Include an image of each interface in appropriate section. Can maybe refer to Fig. 7.1 but it currently lacks some of the interfaces. 7 7.3.1 TPC Electronics 8 sec:fdsp-daq-intfc-elec Summarise TPC/DAQ interface 9 7.3.2 PD Electronics 10 sec:fdsp-daq-intfc-photon Summarise photon system/DAQ interface. 11 7.3.3 Offline Computing (Kurt Biery) 12 sec:fdsp-daq-intfc-fnal-cmptg Where the data goes after it leaves DAQ. 13 7.3.4 Slow Control 14 sec:fdsp-daq-intfc-ext Summarise the interface with slow control. 15 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  94. Chapter 7: Data Acquisition System 7–81 7.3.5 External Systems (Giles & Alec) 1 sec:fdsp-daq-intfc-ext Need to receive information on beam spills (Giles) , SNEWS (Alec). 2 The DAQ will need to save data based on external triggers, for example: for times around when the 3 pulse of neutrinos from LBNF arrives at the Far Detector; or if notice of an interesting astrophysical 4 snews event is given by SNEWS [ ? ] or LIGO. This could involve going back in time to save data that has 5 sec:fdsp-daq-ltr already been buffered (see Sec. 7.2.3), or changing the trigger or zero suppression criteria for data 6 in the interesting time period. 7 Giles’ stuff including the new ways to generate a predictive trigger? Beam Trigger: 8 The Supernova Early Warning System (SNEWS) is a coincidence net- Astrophysical Triggers: 9 work of neutrino experiments which are individually sensitive to the burst of neutrinos which 10 would be observed from a core-collapse supernova somewhere in our galaxy. While DUNE should 11 sec:fdsp-daq-sel be sensitive to such a burst on its own able to contribute to the coincidence network (Sec. 7.2.5) 12 via a tcp socket, being able to save data based on other observations adds an additional chance to 13 not miss saving this rare and valuable data. A SNEWS alert is formed when two or more neutrino 14 experiments report a potential supernova signal within 10 s. The earliest time in the coincidence is 15 then sent via running a script on the SNEWS server at BNL provided by the experiment wishing to 16 receive the alert. The latency from neutrino burst is set by the response time of the second fastest 17 detector to report to SNEWS: this could be as short as seconds, but might be tens of seconds. At 18 latencies larger than 10 s, full data might not be available, but compressed data might writeable. 19 There are other astrophysical triggers available for occurrences which DUNE might not sensitive 20 to individually, but could be either rarely or if taken as an ensemble. Gravitational wave triggers 21 will be available (details being worked out during the current LIGO shutdown), as will high energy 22 photon transients, most notably gamma ray bursts. In fact, cooperation between LIGO/VIRGO, 23 the Gamma Ray Coordinates Network (GCN) 1 , and a number of automated telescopes via network 24 sockets on the time scale of seconds enabled the discovery that “short/hard” gamma ray bursts 25 kilonova are caused by colliding neutron stars [ ? ]. 26 7.4 Production and Assembly (David Newbold) 27 sec:fdsp-daq-prod-assy 1 Page 28 1 Described in detail at https://gcn.gsfc.nasa.gov/gcn_describe.html 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  95. Chapter 7: Data Acquisition System 7–82 7.5 Installation, Integration and Commissioning (David New- 1 bold & Alec Habig) 2 sec:fdsp-daq-install 2 Pages 3 7.5.1 Installation 4 sec:fdsp-daq-install-transport 7.5.2 Integration with TPC/PD Electronics 5 sec:fdsp-daq-install-transport 7.5.3 Commissioning 6 sec:fdsp-daq-commissioning 7.6 Safety (David Newbold & Alec Habig) 7 sec:fdsp-daq-safety 1 Page 8 Two overall safety plans will be followed by the FD-DAQ. Work underground will comply with the 9 safety procedures in place for working in the detector caverns and CUC underground at SURF. 10 In particular, procedures for working with racks full of electronics and/or computers as done at 11 Fermilab will be followed. 2 12 There are not any special safety items for the DAQ system that are not already covered by the 13 more general safety plans referenced above. 14 7.7 Organization and Management (David Newbold & Georgia 15 Karagiorgi) 16 sec:fdsp-daq-org 2 Pages 17 2 which we should cite somehow 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

  96. Chapter 7: Data Acquisition System 7–83 7.7.1 DAQ Consortium Organization 1 sec:fdsp-daq-org-consortium 7.7.2 Planning Assumptions 2 sec:fdsp-daq-org-assmp 7.7.3 WBS and Responsibilities 3 sec:fdsp-daq-org-wbs 7.7.4 High-level Cost and Schedule 4 sec:fdsp-daq-org-cs 23 Feb 2018: First draft of the TP volumes due DUNE Technical Proposal

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