MRPC R&D and production Yongjie Sun Center of Particle Physics and Technology, USTC

2 Jun.7, 2010 Index  Introduction  R&D on MRPC STAR TOF STAR MTD CBM TOF BES ETOF upgrade  Summary

3 Jun.7, 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

4 Jun.7, 2010 Early R&D ( ) beam test at PS-T10, CERN ： efficiency >95% （ 5 gas gaps ） >97% （ 6 gas gaps ） ~ 99% （ double stack 2  5 gas gaps ） time resolution ~70ps （ 5 gas gaps ） ~60ps （ 6 gas gaps ） ~50ps （ double stack 2  5 gas gaps ） M.Shao, L.J.Ruan, H.F.Chen et al., NIM A492(2002) MRPCs of different structures 60 working gas mixture: F134A(90%) ＋ iso- C4H10 (5%) ＋ SF6(5%)

5 Jun.7, 2010 STAR Upgrade -PID TPC - tracking MRPC TOF (TOFr) – stop time measurement VPD - start time measurement Particle momentum dE/dx ~8% resolution  /K separation to ~0.6GeV/c k/p separation to ~1.0GeV/c Aim at 100ps time resolution TOF system  /K separation to ~1.6GeV/c & k/p separation to ~3.0GeV/c

6 Jun.7, 2010 MRPC strip size ： 3.15cm×6.30cm Module size ： 21.2×9.4×1.79 cm 3 Gas gap ： 6×0.22mm In 200 GeV central Au+Au: Time resolution <100ps Efficiency  90% High granularity Rate >200Hz/cm 2 MRPC Structure for STAR/TOF

7 Jun.7, 2010 TOFr Tray Configuration Total:  Area: 64 m 2  3840 MRPC modules  ~23,000 channels Tray:  6  in azimuth  1 in pseudo-rapidity  radius ~ 2.2 m

8 Jun.7, 2010 Completed Prototype 28 module MRPC TOF Tray installed in STAR Oct. ‘ 02 in place of existing central trigger barrel tray Neighbor CTB Tray EMC Rails FEE STAR-TOF prototypes TOFr Tray (1/120 coverage of Barrel STAR)   85 ps, 2 meter path 28MRPC, 24 made at USTC

9 Jun.7, 2010 MRPC Mass Production  After STAR Construction Readiness Review in April 2006, MRPC mass Production in China started. University of Sci. & Tech. of China (USTC) will produce 1210 MRPCs 1/23/45/67/811/12 9/10 1/23/45/67/811/12 9/10 1/23/45/67/ Prod. Start 40 MRPCs +192 MRPCs +326 MRPCs

10 Jun.7, m 2 clean room ( cleanness class 100K ): Temperature ： 25 o C Humidity ： <40% 4 assembly desk ( cleanness class 100 ) MRPC Mass production

11 Jun.7, 2010 MRPC mass production

12 Jun.7, 2010 Mass Production QA/QC QA/QC on all materials, production procedure, and produced MRPC modules

13 Jun.7, 2010 QA of materials glassPCB honeycombsupporter

14 Jun.7, 2010 QC setup – cosmic ray telescope QC capability: 8 MRPCs / Day

15 Jun.7, 2010 Monthly output 2006 Month Output 2007 Month Output Month Output Jun.12Jan.58Jul.120 Jul.64Feb.24Aug.120 Sep.55Mar.83Sep.119 Oct.35Apr.80Oct.121 Nov.42May.126Nov.120 Dec.22Jun.82 Total Totally, 1283 MRPCs have been produced.

16 Jun.7, 2010 Long time stability More stable at late production stage

17 Jun.7, 2010 TOF Time Resolution Summary 2003 to 2009 Operation condition Time Resolution (ps) VPD (start time) TOFr (overall) TOFr (stop time) Run III 200GeV d+Au ~85~120~85 200GeV p+p ~140~160~80 Run IV 62GeV (Au+Au) ~55~105~89 200GeV (Au+Au) FF/RFF ~27~74~70 HF ~20~74~71 Run V 200GeV Cu+Cu (TOT) ~ 50~92~75 62GeV Cu+Cu (TOT) ~ 82~125~94 Run VIII 200 GeV d+Au NA 200 GeV p+p (TOT) ~83~112~75 Run IX 500 GeV p+p (preliminary) ~85~115~78

18 Jun.7, 2010 Long-strip MRPC 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

19 Jun.7, 2010 Possible applications  STAR MTD (Muon telescope Detector)  CBM TOF Wall (outer part) MTD

20 Jun.7, 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/ □

21 Jun.7, 2010 Photos of construction

22 Jun.7, 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

23 Jun.7, 2010 Cosmic ray test results

24 Jun.7, 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

25 Jun.7, 2010 Beam Test results Efficiency plateau Time resolution 1/v ~ 60ps/cm Position resolution: ~ 1 cm

26 Jun.7, 2010 Installed on STAR  Three such LMRPCs have been installed to STAR and successfully taken data since year  A STAR/MTD proposal was submitted based on these data.

27 Jun.7, 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

28 Jun.7, 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

29 Jun.7, 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

30 Jun.7, 2010 Efficiency and resolution plateau 67 ps 97%

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

32 Jun.7, 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

33 Jun.7, 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

34 Jun.7, 2010 Transverse profile—strip center

35 Jun.7, mm-gap Transverse profile—strip edge

36 Jun.7, 2010 Spatial resolution 1/v~ 60 ps/cm

37 Jun.7, 2010 BES/ETOF upgrade  Current ETOF muon: 110ps Electron: 148ps pion: 138ps (average 1.1GeV for 2 σ π/K separation, but varying is from 0.9 to 1.3 GeV)  MRPC ETOF Not too affected by scattering Total time resolution < 80ps  Non-intrinsic: ~ 50ps  MRPC: < 50ps >1.4GeV for 2 σ π/K separation

38 Jun.7, 2010 Design: 36 sectors with overlapping  The edges of MRPC are insensitive  Overlapping  Space requirement of Front End Electronics  36 sectors instead of 48

39 Jun.7, 2010 MRPC prototype design  12 strips, 2 ends read out Length: cm Width: 2.5 cm  Gas gaps:  0.22 mm × 6 × 2 stacks  Module thickness:≤22 mm (without the gas box)

40 Jun.7, 2010 photos of the assembly

41 Jun.7, 2010 Summary  MRPC is successfully designed and mass produced for STAR TOF. The performance is uniform and stable, satisfied the STAR requirements.  Long-strip MRPC shows good performance: Efficiency: > 97% Time resolution: ps spatial resolution: less than 1 cm. Cross talk: < 3%  MRPC for other applications is also considered.  Look forward to cooperate with NICA/MPD project. Thank you!

42 Jun.7, 2010

43 Jun.7, 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

44 Jun.7, 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

45 Jun.7, 2010 Cross Talk MRPC #2 Valid TDCs and QDCs

46 Jun.7, 2010 Efficiency vs. Position Valid TDCs HV=±7 kV

47 Jun.7, 2010 Valid TDCs and valid QDCs (3 sigma above pedestal)

48 Jun.7, 2010 Cross Talk MRPC #3

49 Jun.7, 2010 Efficiency vs. Position Valid TDCs 7mm-gap between strips