STAR regional meeting, October UniversityWang Yi, Tsinghua University New MRPC R&D in Tsinghua University Outline: Introduction of MRPC MRPC for RHIC STAR-TOF LMRPC for STAR-MTD High rate MRPC for CBM-TOF Conclusions 1 Wang Yi Department of Engineering Physics Tsinghua University

STAR regional meeting, October UniversityWang Yi, Tsinghua University 2 Introduction of MRPC Large area, high granularity Good time resolution<100ps High efficiency> 95% Low cost Was used or will be used in ALICE, STAR, FOPI, HADES HARP, CBM and NICA-MPD

STAR regional meeting, October UniversityWang Yi, Tsinghua University 3 4 gaps, used in HADEs-TOF 6 gaps, used in STAR-TOF 10 gaps, used in ALICE-TOF Four kinds of MRPC prototypes 90cm 3.8cm Gap 6mm 6gaps, used in STAR-MTD

STAR regional meeting, October UniversityWang Yi, Tsinghua University 4 MRPCs used in hadron experiment 95/0/

STAR regional meeting, October UniversityWang Yi, Tsinghua University 5 QCD phase diagram The goal of hadron experiments are to search the QGP and find the origin of cosmology. Our goal is to develop high quality Time of Flight system for these hadron experiments! RHIC-STAR FAIR-CBM NICA-MPD JLAB upgrade project …..

STAR regional meeting, October UniversityWang Yi, Tsinghua University 6

STAR regional meeting, October UniversityWang Yi, Tsinghua University 7 MRPC used in STAR barrel TOF Long side view

STAR regional meeting, October UniversityWang Yi, Tsinghua University 8 Glass: ～ 4×10 12 .cm Carbon tape: 500k  / Gas gap: 6×0.22mm Working gas: 95% F134a+5% iso-butane Time resolution: 70ps Efficiency >95% 3cm 6cm Readout pad Performance of STAR-TOF MRPC PID of TOF:  /k ~1.6 GeV/c ( ,k)/p ~ 3.0 GeV/c

STAR regional meeting, October UniversityWang Yi, Tsinghua University 99 1/23/45/67/811/12 9/10 1/23/45/67/811/12 9/10 1/23/45/67/ Prod Start 132 MRPCs 768 MRPCs 1856 MRPCs 2944 MRPCs 4032 MRPCs MRPC production scheme MRPC production was finished in September of In Tsinghua: 3100 MRPC have been produced; 2951 Modules passed QA, yield >95% ; 2840 modules shipped to UT Austin. Great success!

STAR regional meeting, October UniversityWang Yi, Tsinghua University 10 A large area of muon telescope detector (MTD) at mid-rapidity, allows for the detection of di-muon pairs from QGP thermal radiation, quarkonia, light vector mesons, possible correlations of quarks and gluons as resonances in QGP, and Drell-Yan production single muon from the semi- leptonic decays of heavy flavor hadrons advantages over electrons: no  conversion, much less Dalitz decay contribution, less affected by radiation losses in the detector materials, trigger capability in Au+Au trigger capability for low to high pT J/  in central Au+Au collisions excellent mass resolution, separate different upsilon states e-muon correlation to distinguish heavy flavor production from initial lepton pair production STAR Muon Telescope Detector

STAR regional meeting, October UniversityWang Yi, Tsinghua University 11 Iron bars Muon penetrates iron bars, other particles are stopped Good Time Resolution (60-70ps): rejects background greatly 1 hit per 5 head-on Au+Au: Dimuon trigger Large coverage: diameter of 7 meters Simulation: Hadron Rejection and Muon Trigger at STAR

STAR regional meeting, October UniversityWang Yi, Tsinghua University 12 Concept of Design of the STAR-MTD A detector with long-MRPCs covers the whole iron bars and leave the gaps in- between uncovered. Acceptance: 45% at |  |< modules, 1404 readout strips, 2808 readoutchannels Long-MRPC detector technology, HPTDC electronics (same as STAR-TOF)                     

STAR regional meeting, October UniversityWang Yi, Tsinghua University 13 LMRPC for STAR-MTD

STAR regional meeting, October UniversityWang Yi, Tsinghua University 14 LMRPC for STAR-MTD Readout strips: 3.8cm x 90cm x 12 Inter-strip separation: 6 mm Gas gaps: 0.25 mm x 6 Outer glass: 1.1 mm Inner glass: 0.7 mm HV electrode: colloidal graphite ~4 MΩ/ Strip length: 90cm Strip width: 3.8cm Inter-strip separation:0.6cm Filter circuit

STAR regional meeting, October UniversityWang Yi, Tsinghua University 15 Surface resistivity distribution of electrode 20 points, average: 4.3M  / □ minimum: 2.9M  / □ maximum: 5.8M  / □

STAR regional meeting, October UniversityWang Yi, Tsinghua University 16 System layout of cosmic ray 2cm*2cm*4cm scintillators above and below the module cm*5cm*20cm scintillators Above and below the module Efficiency: determined by S3, S4, LMRPC Resolution: calculated with S0,S1, S2,LMRPC PMT0 PMT1 PMT3 PMT2 PMT4 PMT5 PMT6 LMRPC s1s1 s0s0 s2s2 s3s3 s4s4

STAR regional meeting, October UniversityWang Yi, Tsinghua University 17 Efficiency and time 4000 events, time is 65ps 95%Freon/5%iso-butane : 7000V, time resolution <100ps 94%Freon/5%iso-butane/1%SF6 : 7200V, time resolution ~ 75ps

STAR regional meeting, October UniversityWang Yi, Tsinghua University 18 Noise rate Noise < V

STAR regional meeting, October UniversityWang Yi, Tsinghua University 19 Uniformity 94%Freon/5%iso-butane/1% 7500V Efficiency ~ 95%Time resolution 60~80ps Not bad uniformity!

STAR regional meeting, October UniversityWang Yi, Tsinghua University 20 Particle e+, e-,  +,  -,p momentum e200MeV/c~1.3GeV/c  400MeV/c~900MeV/c p500MeV/c~1GeV/c rate3~4Hz Beam-test area in IHEP

STAR regional meeting, October UniversityWang Yi, Tsinghua University 21 Detector system at experiment area Trigger and PID position T0(trigger) and MRPC C0 MWPC MRPC PMT1&2 PMT3&4 MRPC

STAR regional meeting, October UniversityWang Yi, Tsinghua University 22 Efficiency & time resolution for proton Efficiency > 6600V Time resolution ~ 70ps

STAR regional meeting, October UniversityWang Yi, Tsinghua University Trigger: 2cm x 4cm Move trigger: Efficiency Time resolution Trigger scan -- vertical

STAR regional meeting, October UniversityWang Yi, Tsinghua University Move trigger: Good uniformity!! Efficiency ~ 99% Time resolution ~ 55ps Trigger scan -- horizontal

STAR regional meeting, October UniversityWang Yi, Tsinghua University 25 Signal propagation velocity T_diff/2 = x0+dx/v 1/v = 56 ps/cm Good linearity Charge at two ends of one 6800V

STAR regional meeting, October UniversityWang Yi, Tsinghua University 26 1/23/4 5/6 7/8 9/1011/121/2 3/4 5/67/8 9/10 11/12 Plan Start 20 LMRPCs 40 LMRPCs 60 LMRPCs 80 LMRPCs 100 LMRPCs 115 LMRPCs LMRPC manufacture milestones Tsinghua : 65 USTC: 50 We want to duplicate STAR-TOF’s success!

STAR regional meeting, October UniversityWang Yi, Tsinghua University 27 Full system time resolution  T ~ 80 ps Efficiency > 95 % Rate capability ~ 20 kHz/cm 2 Acceptable cross-talk and charge-sharing Pile-up < 5% Occupancy < 5 % Spatial resolution FAIR-CBM TOF CBM

STAR regional meeting, October UniversityWang Yi, Tsinghua University 28 Possible Solution: – Timing RPC with low resistivity glass ~10 10 Ωcm – Center: pad-readout Outside: strip-readout CBM-TOF requirement kHz/cm 2 8kHz/cm kHz/cm kHz/cm kHz/cm 2

STAR regional meeting, October UniversityWang Yi, Tsinghua University 29 World map of MRPC’s rate capability

STAR regional meeting, October UniversityWang Yi, Tsinghua University 30 Performance of low resistivity glass Specifications: Maximal dimension: 50cm×50cm Bulk resistivity: ~10 10 .cm Standard thickness: 0.5mm--2mm Thickness uniformity:  0.02mm Dielectric constant: ~10 Surface roughness: <10nm DC measurement: very stable

STAR regional meeting, October UniversityWang Yi, Tsinghua University 31 Scanned images of glass 2-D image 3-D image

STAR regional meeting, October UniversityWang Yi, Tsinghua University 32 MRPCs with different structure 2 cm 13 cm 97cm 2.5cmGap 4mm

STAR regional meeting, October UniversityWang Yi, Tsinghua University 33 Beam test for rate capability PMT: kHz/cm 2 MRPC: 2-30 kHz/cm 2 Charge distributions of the 10-gap RPC for different particle fluxes at 2.64 kV/gap

STAR regional meeting, October UniversityWang Yi, Tsinghua University 34 Performance of high rate MRPC Efficiency and time resolution as a function of high voltage at a rate of about 800Hz/cm 2 When the particle flux increases every 5 kHz/cm 2, the efficiency decreases by 1% and the time resolution deteriorates by 4 ps.

STAR regional meeting, October UniversityWang Yi, Tsinghua University 35 HV scan (strip readout module) T diff =T MRPC#3 -T MRPC#4, σ MRPC#3 ≈ σ MRPC#4 ≈ σ diff / sqrt(2)

STAR regional meeting, October UniversityWang Yi, Tsinghua University 36 Position Scan 231 Rpcy "or" eff strip1 strip2 strip3 "and" eff Efficiency(%) Rpcy(mm) MRPC#3 MRPC#4

STAR regional meeting, October UniversityWang Yi, Tsinghua University 37 Crosstalk & charge sharing- doped glass 231 Rpcy (cm) 20% 10% Crosstalk_1=counts(T2>0 && T1>0) / counts(trigger)

STAR regional meeting, October UniversityWang Yi, Tsinghua University 38 Crosstalk & charge sharing- common glass 231 Rpcy (cm) 2% Crosstalk_1=counts(T2>0 && T1>0) / counts(trigger)

STAR regional meeting, October UniversityWang Yi, Tsinghua University 39 Position resolution T1T2 DeltaT=(T2-T1)/2 Using the tracking, we get the signal propagation velocity: ~ 61ps/cm Position resolution: <5 mm

STAR regional meeting, October UniversityWang Yi, Tsinghua University 40 Conclusions Development of 6-gap MRPC for STAR-TOF, time resolution 95% 3100 MRPCs were assembled for STAR-TOF, yield>95% Development of LMRPC for STAR-MTD, time resolution 95%, noise rate<1Hz/cm 2 Development of low resistive glass with resistivity ~ Ωcm Development of pad- and strip- readout high rate MRPCs, rate capability>25kHz/cm 2, time resolution<80ps Application in NICA-MPD and Jefferson lab,.…

STAR regional meeting, October UniversityWang Yi, Tsinghua University 41 Thanks for your attention!