长读出条 MRPC 性能研究 孙勇杰 Key Laboratory of Technology of Particle Detection and Electronics, USTC-IHEP, CAS Center of Particle Physics and Technology, USTC

NanChang University 2 Apr. 18, 2010 Introduction MRPC (Multi-gap Resistive Plate Chamber) is a major new detector technology first developed by the ALICE experiment. The concept first published on Nucl. Instr.& Meth. A374 (1996) 132 by M.C.S.Williams et al. Advantages:  Time resolution  High efficiency  Low cost  Arbitrary readout shape Good candidate for large area Time-Of-Flight system ! MRPC

NanChang University 3 Apr. 18, 2010 MRPC—signal pickup Long-strip readout:  save electronics channels.  Read out at two ends Mean time  Eliminate the position along the strip Time difference  Position information ~3cm ~6cm STAR TOFALICE TOF

NanChang University 4 Apr. 18, 2010 Possible applications  STAR MTD (Muon telescope Detector)  CBM TOF Wall (outer part) MTD

NanChang University 5 Apr. 18, 2010 LMRPC Prototype-I Size: 950 x 256 mm 2 Readout strip: 25 mm wide, 4 mm gaps between strips Active area: 870 x 170 mm 2 Gas gaps: 10 x 0.25 mm, in 2 stacks Glass: 0.7 mm HV electrode: ~200 kΩ/ □

NanChang University 6 Apr. 18, 2010  Trigger area: 20 x 5 cm 2  Time reference (T0)  TOF MRPC was used to get 6 segments along the strip.  Gas: 95% Freon + 5% iso-butane  HV=±6.3 kV LMRPC Cosmic ray test setup

NanChang University 7 Apr. 18, 2010 Cosmic ray test results

NanChang University 8 Apr. 18, 2010 MWPC5 MWPC1MWPC2 MWPC4 TOF1 252”73” TOF2 72”164” 449” LMRPC GEMs MWPC3 191” TOF3 70” Upper stream Down stream C1, C2 Beam Energy: 32 GeV FNAL Beam Test (T963) Beam test setup

NanChang University 9 Apr. 18, 2010 Beam Test results Efficiency plateau Time resolution 1/v ~ 60ps/cm Position resolution: ~ 1 cm

NanChang University 10 Apr. 18, 2010 LMRPC prototype-II Readout strips 2.5 cm Readout strips: 2.5 cm x 50 cm Gaps between strips: 6 mm Gas gaps: 10 x 0.25 mm, in 2 stacks Glass: 0.7 mm HV electrode: ~40 MΩ/ □ 550 mm 241mm 25 mm 6 mm

NanChang University 11 Apr. 18, 2010 SSD Beam FOPI experiment 6m Proton Beam Pb 2m 42 cmPMT 1,2 PMT 3,4 Platform x y Beam Test setup SSD THU MRPC USTC MRPC

NanChang University 12 Apr. 18, 2010 T-(t1+t2+t3+t4)/4 T-(t1+t2+t3+t4)/4-f(A) T-(t1+t2+t3+t4)/4 ADC ADC MRPC Calibration MRPC time resolution ~ 67 kV. (including momentum spread) ((t 3 +t 4 )-(t 1 +t 2 ))/4 PMT Resolution ~67 ps

NanChang University 13 Apr. 18, 2010 Efficiency and resolution plateau 67 ps 97%

NanChang University 14 Apr. 18, 2010 Position scan (±7 kV) No significant efficiency drop in the gap Trigger Area: 2 cm wide From both “ charge sharing ” and cross talk.

NanChang University 15 Apr. 18, 2010 Valid TDCs and valid QDCs (3 sigma above pedestal) Valid TDCs Cross Talk Trigger on the strip center: “ Cross talk ” at neighbor strips: <~3% Trigger Area: 2 cm wide

NanChang University 16 Apr. 18, 2010 Hits position profile on MRPC the profile is about 3cm x 2 cm the following analysis will base on these SSD position cuts and charge cuts

NanChang University 17 Apr. 18, 2010 Transverse profile—strip center

NanChang University 18 Apr. 18, mm-gap Transverse profile—strip edge

NanChang University 19 Apr. 18, 2010 Combined

NanChang University 20 Apr. 18, 2010 Summary  Long (0.5 m, 0.9 m) readout-strip MRPCs were successfully constructed and tested. Efficiency: > 97% Time resolution: ps spatial resolution: less than 1 cm. Cross talk: < 3%  LMRPC shows prospective application as TOF in low multiplicity environments.  Two LMRPCs (0.9m) have already been installed to STAR as part of the MTD detector and have successfully taken data since year Thank you!

NanChang University 21 Apr. 18, 2010

NanChang University 22 Apr. 18, 2010

NanChang University 23 Apr. 18, 2010 Longitudinal Valid TDCValid TDC & QDC

NanChang University 24 Apr. 18, 2010 charge vs position

NanChang University 25 Apr. 18, 2010 Signal Charge vs Position near the edge of stripat the middle of strip

NanChang University 26 Apr. 18, 2010 MRPC #2 (topview) Top/bottom pcb The readout strips are “ hollowed-out ” alternately. Removed: 5 mm x 4 Left: 1 mm x 5 Removed: 2.5 mm x 9 Left: 0.25 mm x 10

NanChang University 27 Apr. 18, 2010 MRPC #3 (topview) 55 cm 24.1cm 2.5cm 0.7cm Gaps between strips: 0.7 cm (upper part) 0.8 cm (lower part) 0.8cm

NanChang University 28 Apr. 18, 2010 Cross Talk MRPC #2 Valid TDCs and QDCs

NanChang University 29 Apr. 18, 2010 Efficiency vs. Position Valid TDCs HV=±7 kV

NanChang University 30 Apr. 18, 2010 Valid TDCs and valid QDCs (3 sigma above pedestal)

NanChang University 31 Apr. 18, 2010 Cross Talk MRPC #3

NanChang University 32 Apr. 18, 2010 Efficiency vs. Position Valid TDCs 7mm-gap between strips