T09: ETL Reference Design Overview (402.8.4) Artur Apresyan Fermilab US-MTD Technical Review 15-16 November 2018
Outline § Introduction to ETL § Technical requirements § Description of mechanics, interfaces, dependencies § Construction, installation, operation, maintenance § Major R&D items and path to baseline design § Overall schedule and milestones § Value engineering § ES&H, QA and Q&C § Summary A. Apresyan – T09: ETL Reference Design Overview (402.8.4) US-MTD Technical Review 2
Charge #6 Biographical sketch § Associate scientist at Fermilab § L3: Endcap Timing Layer (ETL) in US-MTD § ETL Engineering in international MTD § CMS HCAL and ECAL offline reconstruction, § HCAL DQM development and maintenance, HCAL noise working group, MET reconstruction § Quality assurance development and implementation § CDF: FPix QC framework at Purdue § Development of precision timing detectors § Multiple publications on timing detectors based on SiPM, MCPs, and LGADs § DOE ECA award in 2018 to work on precision timing detectors § FNAL LDRD award in 2017 to work on LGAD sensors R&D A. Apresyan – T09: ETL Reference Design Overview (402.8.4) US-MTD Technical Review 3
Charge #1,5 ETL Design and Performance Specification § Particle flow reconstruction performance at high PU to comparable to Phase-1 CMS. § Extend the CMS physics reach in a broad class of new physics searches with long-lived particles § Achieve radiation tolerance up to 2x10 15 n eq /cm 2 at |η| = 3.0 § Fluence is less than 1x10 15 n eq /cm 2 for 80% of the ETL surface area § Channel occupancy below 10% to ensure small probability of double hits, needed for unambiguous time assignment § Channel size ~3mm 2 in the highest η, and ~1 cm 2 in lowest η § The ETL detector designed to be accessible for repairs and replacements of faulty components § Maintain an independent cold volume which is isolated and operated separately from the HGCal § MIP Timing Layer HL-LHC Systems Engineering § https://cms-docdb.cern.ch/cgi-bin/DocDB/ShowDocument?docid=13536 A. Apresyan – T09: ETL Reference Design Overview (402.8.4) US-MTD Technical Review 4
ETL Overview “BTL” Barrel “BTL” Within TST – 20mm thick Surface – 40 m 2 Radiation level – 2E14 n eq /cm 2 Sensors: LYSO crystals + SiPMs “ETL” Endcaps “ETL” On the CE nose – 42 mm thick Surface – 17.5 m 2 Radiation level – 2E15 n eq /cm 2 Sensors: Si w/ internal gain - LGADs Design Principle: Provide precision time resolution of 30-40ps while ensuring radiation tolerance to 4/ab. A. Apresyan – T09: ETL Reference Design Overview (402.8.4) US-MTD Technical Review 5
Charge #1,5 LGAD sensors § Silicon sensors with specially doped thin region that produces high electric field à produces avalanche signal with 10-30 gain § Large community: § RD50 collaboration § Several manufacturers: CNM, FBK, Hamamatsu § Demonstrated time resolution ~30 ps up to 1x10 15 n eq /cm 2 , and about 40 psec up to 2x10 15 n eq /cm 2 high uniformity FBK wafer with CMS- and ATLAS- sensors LGAD signal amplitude distribution is fitted to a Particle detection efficiency across sensor surface Landau function. A. Apresyan – T09: ETL Reference Design Overview (402.8.4) US-MTD Technical Review 6
Charge #1,5 Readout ASIC § A unique ASIC will need to be developed to accomplish the needs § Radiation hard, 256 LGAD pixels per ROC, large area sensors § Measurement of time-of-arrival in every pixel with ~40 ps time resolution § Synchronization/calibration, drift of parameters due to radiation § Target: <4mW/channel, 12.5 μs storing capability + trigger matching readout § Design choice is to focus on TSMC 65nm § Vast experience in the community, shared expertise from libraries and rad. dam. studies Schematic diagram of the first prototype ETROC A. Apresyan – T09: ETL Reference Design Overview (402.8.4) US-MTD Technical Review 7
ETL Structure § General structure § LGAD+ASIC assemblies mounted on Aluminium nitrate carrier plates § Groups of 12 sensors (each ~2x4 cm 2 ) mounted on a common carrier § Flexible circuit wirebonded to ASICs, pigtail connectors connect to Readout PCB § Power and Readout PCB mounted on the same carrier § Dual-phase CO 2 cooling is used to evacuate the heat § One lpGBT per module, VTrx+ to send data with optical link to backend Al wedge CO2 cooling pipes LGAD sensors Power PCB Readout PCB A. Apresyan – T09: ETL Reference Design Overview (402.8.4) US-MTD Technical Review 8
ETL Structure § General structure § LGAD+ASIC assemblies mounted on Aluminium nitrate carrier plates § Groups of 12 sensors (each ~2x4 cm 2 ) mounted on a common carrier § Flexible circuit wirebonded to ASICs, pigtail connectors connect to Readout PCB § Power and Readout PCB mounted on the same carrier § Dual-phase CO 2 cooling is used to evacuate the heat § One lpGBT per module, VTrx+ to send data with optical link to backend Al wedge CO2 cooling pipes LGAD sensors Power PCB Readout PCB A. Apresyan – T09: ETL Reference Design Overview (402.8.4) US-MTD Technical Review 9
Charge #1 ETL Structure § ETL detector will be placed on the nose of HGCal § Cover the range in 1.6<|η|<2.9 § Total silicon surface area of 17.5 m 2 for the two Z-sides. § Total thickness of the ETL detector is ~42 mm, § Disks populated with modules on both sides § Independent cold volumes, and accessibility for ETL Thermal screen is extracted there R=1.27 m R=0.31 m 2 ETL disks A. Apresyan – T09: ETL Reference Design Overview (402.8.4) US-MTD Technical Review 10
Charge #7 Interfaces and dependencies § There are a range of critical interfaces to be considered in the project § Mechanical: detector envelope is limited by the space available between HGCal and OT § Mechanical: Services passed through dedicated channels inside/outside HGCal § Electrical/optical: connector types and locations for cable flow volumes, power, bias voltage, optical fibers, safety system sensors § Logical: data formats between ETROC and off-detector electronics, trigger and clock distribution § Overall integration issues are the responsibility of the international MTD technical coordination team § Common CO 2 cooing plant development for all CMS projects § Documentation and reviews of key specifications and interfaces § Engineering designs will be fully documented in CERN EDMS in advance of the Engineering Design Reviews or Electronics System Reviews which will proceed construction of each major subsystem § Sign-off will be required from the project technical coordinator as well as the area coordinators of the affected sections of the detector § Reviews will include the US-CMS project engineers and managers § CMS Technical Coordination workshop on October 29, 2018 A. Apresyan – T09: ETL Reference Design Overview (402.8.4) US-MTD Technical Review 11
Charge #2 ETL Construction and Operation § There is extensive knowledge about fabrication, installation, and operation of a silicon detectors in colliders § Modules are very similar to tracker and pixel detectors § Construction simpler than typical tracker detectors § ETL construction performed at assembly centers § Modules assembled with the use of an automated placement gantry, as for the original CMS tracker, and for HGCal. § Will reuse the existing facilities and expertise for the construction § The robotic assembly is simpler in ETL due to relaxed alignment tolerances and small number of components. § After curing of glue attaching the bump-bonded sensors to the AlN substrate, the ASICs will be wire-bonded to the readout flex § The functionality of a single sensor assembly can be tested. § Good sensors will then be mounted into modules and retested. § An overnight burn-in and thermal test for each module. § Extensive long term stress testing on modules during pre-production § Repeated on a small number of modules during production A. Apresyan – T09: ETL Reference Design Overview (402.8.4) US-MTD Technical Review 12
Charge #2 ETL Construction and Operation § Full integration of the Dees occurs on the surface in the lab: only connection checkout underground § Modules shipped to CERN to populate wedges § Modules will be mounted on wedges at CERN in a lab equipped with a CO 2 cooling plant, power, and DAQ infrastructure to test a wedge at cold temperatures. Layout of the cooling loops inside a wedge § Commission the ETL at the same coolant temperature as HGCAL § A cooling system common with HGCal § During detector operations § Assume always at -35 C CO 2 exit temperature (as other CO 2 -cooled systems in CMS), apart from during maintenance Finite element model simulation of a section of the ETL § FEA simulations demonstrate that silicon support, displaying sensor temperatures sensors will kept at an operating temperature below −20 C A. Apresyan – T09: ETL Reference Design Overview (402.8.4) US-MTD Technical Review 13
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