RPC 2016 XIII Workshop on Resistive Plate Chambers
RPC 2016 – XIII Workshop on Resistive Plate Chambers and Related Detectors Performance studies of a single HV stack MRPC prototype for CBM Ingo Deppner Physikalisches Institut der Uni. Heidelberg Outline: • CBM-To. F requirements • TDR Tof wall design • Test beam time at GSI • Single stack vs. double stack • Performance results • Summary / Outlook Ingo Deppner RPC 2016 Gent 22 - 26. 02. 2016 Het Pand 1
CBM spectrometer Engineering design of the CBM experiment TRD TOF RICH Magnet Nominal To. F position is between 6 m and 10 m from the target Movable design allows for optimization of the detection efficiency of weakly decaying particles (Kaons) STS Interaction rate 10 MHz Ingo Deppner RPC 2016 Gent 22 - 26. 02. 2016 2
Incident particle flux URQMD simulated charged particle flux for Au + Au (minimum bias) events at 25 AGe. V assuming an interaction rate of 10 MHz k. Hz/cm 2 Ingo Deppner RPC 2016 Gent 22 - 26. 02. 2016 • Flux ranging from 0. 1 to 100 k. Hz/cm 2 • At different regions MRPC counters with different rate capabilities are needed 3
Requirements Charged hadron identification is provided by Time-of-Flight (To. F) measurement CBM-To. F Requirements Ø Full system time resolution s. T ~ 80 ps Ø Efficiency > 95 % Ø Rate capability 30 k. Hz/cm 2 Ø Polar angular range 2. 5° – 25° Ø Occupancy < 5 % twisted Øtwisted Low power electronics RPC pair cabe (~120. 000 channels) feed through Ø Free gas box streaming data acquisition 120 W 80 W 1 ns Ingo Deppner RPC 2016 Gent 22 - 26. 02. 2016 4
TDR To. F wall layout Ingo Deppner RPC 2016 Gent 22 - 26. 02. 2016 • 6 types of modules (M 1 – M 6) only • A module contains several MRPC counters • Region containing counters equipped with float glass • Region containing counters equipped with low resistive glass 5
TDR To. F wall layout • 6 types of modules (M 1 – M 6) only • A module contains several MRPC counters • Region containing counters equipped with float glass • Region containing counters equipped with low resistive glass 106368 readout channels Ingo Deppner RPC 2016 Gent 22 - 26. 02. 2016 6
TDR MRPC arrangement Ingo Deppner RPC 2016 Gent 22 - 26. 02. 2016 7
TDR MRPC arrangement 0. 7 Ingo Deppner RPC 2016 Gent 22 - 26. 02. 2016 140 0. 28 12 8
Modules M 1 M 2 M 5 M 4 M 3 M 6 a: MRPC, b: Preamplifier (PADI), c: feed-through PCB, d: connectors, e: crate, f: TDC and read out Ingo Deppner RPC 2016 Gent 22 - 26. 02. 2016 9
Modules M 1 M 4 PADI 8 Module back plane with feed-through GET 4 TDC M 3 M 2 M 5 feed-through PCB M 6 GET 4 TDC a: MRPC, b: Preamplifier (PADI), c: feed-through PCB, d: connectors, e: crate, f: TDC and read out Ingo Deppner 2016 32 RPC channels Gent 22 - 26. 02. 2016 10
MRPC-P 2 prototype Full size demonstrator for high rates (1 - 10 k. Hz/cm 2) Low resistive glass HV electrode (Licron ) 27 x 32 cm 2 Pickup electrode Ingo Deppner RPC 2016 Gent 22 - 26. 02. 2016 Spacers (fishing line) 11
Test beam time @ GSI • Test beam time in October 2014 at GSI (Hades cave) Setup • Sm beam with 1. 2 A Ge. V kin. energy • 5 mm thick lead target • „Uniform“ illumination of the counter surface • Flux on the lower part of the setup was about few hundred Hz/cm 2 • Delivered flux does not meet the CBM requirements • R 143 a 85%, SF 6 10%, i. But 5% THU-Strip Ingo Deppner RPC 2016 Gent 22 - 26. 02. 2016 12
Test beam time @ GSI Full size demonstrator and reference MRPC used for the performance analysis MRPC-P 2 (HD) MRPC differential glass stack single active area 32 x 27 cm 2 strips 32 strip / gap 7/ 3 glass type low resistive glass thickness 0. 7 mm number of gaps 8 gap width 220 mm MRPC-P 2 Ingo Deppner THU-strip (Beijing) differential double 24 7/ 3 low resistive glass 0. 7 mm 250 mm MRPC-P 5 (HD) differential single 2 24 x 27 cm 15 x 4 cm 2 16 7. 6 / 1. 8 mm low resistive glass 1. 0 mm 2 x 4 6 220 mm THU-strip RPC 2016 Gent 22 - 26. 02. 2016 MRPC-P 5 13
2 MRPC concepts Differential singel stack MRPC with 8 gaps vs. Advantages - simpler construction - symmetric signal path - fewer glass plates (#9) - lower weight - impedance matching easy possible (100 ) Disadvantages - higher High Voltage (> 10 k. V) - bigger cluster size Ingo Deppner Differential double stack MRPC with 2 x 4 gaps RPC 2016 Gent 22 - 26. 02. 2016 - lower High Voltage (< 6 k. V) - smaller cluster size Disadvantages - more complex construction - more glass plates (#10) - impedance matching hardly possible (100 ) 14
Counter occupation Active area of overlain counters D. u. t. MRPC-P 2: 32 x 27 cm 2 Reference MRPC-P 5: 15 x 4 cm 2 Plastic: 8 x 2 cm 2 Ingo Deppner RPC 2016 Gent 22 - 26. 02. 2016 15
Efficiency Differential singel stack MRPC with 8 gaps vs. Efficiency > 98 % Efficiency > 96 % Matched hit pairs in dut - ref • Efficiency= • Data points at 11 k. V in the left plot can be compared with 5. 5 k. V in the right plot. • Single stack MRPC shows slightly better efficiency Ingo Deppner Differential double stack MRPC with 2 x 4 gaps Matched hit pairs in dia - ref RPC 2016 Gent 22 - 26. 02. 2016 16
Dt distribution Edge effects Cut 1 Dt distribution Cut 3 Cut selection on the reference counter Cut 1 Cut 3 Ingo Deppner RPC 2016 Gent 22 - 26. 02. 2016 17
Dt distribution Time difference vs. particle velocity Ingo Deppner HV = 11 k. V, Uthr = 200 m. V RPC 2016 Gent 22 - 26. 02. 2016 18
Dt distribution Time difference vs. particle velocity Ingo Deppner HV = 11 k. V, Uthr = 200 m. V RPC 2016 Gent 22 - 26. 02. 2016 19
Time resolution Differential singel stack MRPC with 8 gaps vs. Differential double stack MRPC with 2 x 4 gaps • Data points at 11 k. V in the left plot can be compared with 5. 5 k. V in the right plot. • Single stack MRPC shows slightly time resolution. • Single counter resolution is in the order of 45 ps including all electronic components. Resolution 62 ps Resolution 65 ps Ingo Deppner RPC 2016 Gent 22 - 26. 02. 2016 20
Dt distribution Cluster size • Time resolution does not deteriorate with cluster size bigger than one 80 W 1 ns Ingo Deppner RPC 2016 Gent 22 - 26. 02. 2016 21
Dt distribution Cluster multiplicity • 80 W Counter time resolution below 50 ps up to the highest multiplicity @ an occupancy of about 50% 1 ns Ingo Deppner RPC 2016 Gent 22 - 26. 02. 2016 22
Summary/Outlook Summary Ø TDR is approved. However no final decision regarding counter design is taken. Ø The design of the differential single stack MRPC from Heidelberg is driven by the freestreaming readout impedance matching is realized. Ø The single stack MRPC shows slightly better efficiency and time resolution in comparison to a double stack MRPC. Ø The double stack MRPC shows a smaller cluster size (about 1. 6). Ø Single counter resolution is in the order of 45 ps including all electronic contributions. Ø However, in a free running mode an impedance matched MRPC might show a better performance due to minimized signal reflections. Outlook Ø Load test for all available full size prototypes in Nov. 2015 with heavy ions at SPS CERN Ø Among them 3 full size modules M 4 with counters MRPC 3 a and MRPC 3 b were tested Ø Data analysis is still ongoing Ø Selection of the final layout and counter configurations this year based on beam time results. Ø Start of the low resistive glass production this year Ingo Deppner RPC 2016 Gent 22 - 26. 02. 2016 23
Outlook CBM MRPC 3 b About 1100 channels 20 MRPC x 2. 3 mm & y 3 mm Ingo Deppner RPC 2016 Gent 22 - 26. 02. 2016 24
Outlook Event display after calibration Ingo Deppner RPC 2016 Gent 22 - 26. 02. 2016 • 1 Track (blue) with mult. 8 • 2 Tracks (green) with mult. 7 25
Thank you for your attention Contributing institutions: Tsinghua Beijing, NIPNE Bucharest, GSI Darmstadt, IRI Frankfurt USTC Hefei, PI Heidelberg, ITEP Moscow, HZDR Rossendorf, CCNU Wuhan, Ingo Deppner Special thanks go to: Norbert Herrmann RPC 2016 Gent 22 - 26. 02. 2016 26
Backup Slides 80 W 1 ns Ingo Deppner RPC 2016 Gent 22 - 26. 02. 2016 27
Backup Slides CBM Physics topics Ø Deconfinement / phase transition at high ρB Ø QCD critical endpoint Ø The equation-of-state at high ρB Ø chiral symmetry restoration at high ρB Observables Ø excitation function and flow of strangeness and charm D. Kresan Au + Au @ 25 Ge. V Ø collective flow of hadrons p Ø particle production at threshold energies p K Ø excitation function of event-by-event fluctuations Ø excitation function of low-mass lepton connector non twisted pairs part Ø in-medium modifications of hadrons (ρ, ω, φ → e+e-(µ+µ-), D) Kaon acceptance depends critically on TOF resolution Ingo Deppner RPC 2016 Gent 22 - 26. 02. 2016 28
Backup Slides Ingo Deppner RPC 2016 Gent 22 - 26. 02. 2016 29
Backup Slides Ingo Deppner RPC 2016 Gent 22 - 26. 02. 2016 30
Cuts Selection cuts in ana_hits. C Cut 1 Cut 3 80 W 1 ns Ingo Deppner RPC 2016 Gent 22 - 26. 02. 2016 31
Cuts Selection cuts in ana_hits. C Cut 1 Cut 3 80 W 1 ns Ingo Deppner RPC 2016 Gent 22 - 26. 02. 2016 32
Time – velocity correlation Step 1 (after init_calib) Step 2 1 ns Ingo Deppner RPC 2016 Gent 22 - 26. 02. 2016 33
Results Differential single stack MRPC with 8 gas gaps Ingo Deppner vs. Differential double stack MRPC with 2 x 4 gas gaps RPC 2016 Gent 22 - 26. 02. 2016 34
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