Beam Condition Monitor Introduction Martin Bieker on behalf of the - PowerPoint PPT Presentation

Beam Condition Monitor Introduction Martin Bieker on behalf of the Dortmund BCM group BCM / WPE introduction meeting— 06.07 .2020

Motivation ‣ LHCb Experiment at the LHC • Sensitive detectors close the high energy LHC beams • Susceptible to adverse beam conditions - Misaligned beams - Particle showers ‣ LHCb Vertex Locator with small aperture Martin Bieker | BCM Introduction 2

Beam Conditions Monitor ‣ 2 Stations • BCM-U: Shielding wall in VELO alcove • BCM-D: Between TT/UT and magnet BCM-U BCM-D Martin Bieker | BCM Introduction 3

BCM components ‣ 8 diamond sensors per station • 10 mm × 10 mm × 0.5 mm ‣ Circular support structure • BCM-U: Aluminium • BCD-D: Tecapeek ‣ Read out by charge to frequency converter (CFC) cards ‣ Modified LHCb backend board Martin Bieker | BCM Introduction 4

Front-end electronics ‣ Current Frequency Converter (CFC) cards • 8 channels • Current integrated over 40 μ s • 12bit ADC ‣ Data transfer • 2 redundant optical links • 800 Mbit/s 8b10b encoded data stream • CRC-32 for error detection Martin Bieker | BCM Introduction 5

Diamond sensors ‣ Polycrystalline CVD diamonds ‣ 8 mm x 8mm Ti/Au metallisation ‣ Operated @ 200 V bias voltage ‣ ≅ 3 fC deposited charge per Sr-90 electron ‣ < 1 pA dark currents measured in lab setup Martin Bieker | BCM Introduction 6

Lab setup ‣ Single diamond in holder inside light/ EMI shielding box ‣ Steady state DC current measured with pico ampere meter ‣ 13.4 MBq Sr-90 source with variable distance Martin Bieker | BCM Introduction 7

Characterisation test beam ‣ Currently no CCE/CCD measurement possible • Measure charge deposited by single particles (DONNA project WIP) • Use defined particle flux -> accelerator beam ‣ Previous iteration of BCM diamonds characterised at ELBE source • 20 MeV electron beam • Beam current: 71 fA to 225 pA [arXiv: 1001.2487] Martin Bieker | BCM Introduction 8

Backup

Beam dump logic Current Measurements every 40 μ s Short range abort (~1 LHC turn) Long range abort (~14 LHC turn) Sum current per diamond Apply threshold for each over 32 measurements diamond and frame Sum diamonds in each station Threshold passed for two (excluding 2 largest and consecutive measurements ? smallest) In three neighbouring diamonds? Apply threshold Request beam dump via LHC interface Martin Bieker | BCM Introduction 10

Readout during run 1&2 Martin Bieker | BCM Introduction 11

Data generator & input chain Bus widths 1b 8b 10b 16b 20b Data Arria V 8b10b word Data Word Aligner FIFO LVDS RX decoding ordering stripping Data valid Parallel Loopback Serial Loopback Bit slip CFC data 8b10b encoded Arria V CFC data FIFO Frame Encoder Data Framer LVDS RX Generator 800 MHz 80 MHz 40 MHz Martin Bieker | BCM Introduction 12

Upgrade readout Post Mortem data Mini crate CFC-U MIBAD Card 12 xOM 2 OM 3/4 PCIe40 SFP+ SFP+ PP Full Stream Data Mezzanine Mini crate CFC-D Slow Control/ WinCC VELO CIBU PMT UX85B D3 rack Computing Farm Martin Bieker | BCM Introduction 13

MIBAD Board Machine Interface Beam Abort Decision ‣ Based on Arria V Starter Kit ‣ 8 optical links via TerasIC SFP- HSMC Card • 4x LVDS “downlink” to CFC cards • 4x XCVR “uplink” to PCIe40 ‣ Interface to LHC(b) via custom BCM mezzanine card Martin Bieker | BCM Introduction 14

MIBAD architecture CFC Input/ Data Generator Data & Frame Data BCM U Monitoring Info Uplink to PCIe 40 check&sync processing Abort Control Unit Decision Threshold settings, Configuration command, BCM D LHC state, etc Machine Interface (CIBU, BCM_OK, PMT) 15 Martin Bieker | BCM Introduction