MRPC for STAR MTD upgrade
description
Transcript of MRPC for STAR MTD upgrade
MRPC for STAR MTD upgrade
Yongjie Sun
Center of Particle Physics and TechnologyUniversity of Science and Technology of China
2010-10-23 STAR Regional Meeting, Ji'nan, China 2
Index
Introduction R&D on Long-strip MRPC Summary
2010-10-23 STAR Regional Meeting, Ji'nan, China 3
1. Muons: Penetrating Probes
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 muons from their semi- leptonic decays of heavy flavor hadrons
• advantages over electrons: no conversion, much less Dalitz decay contribution, less affected by radiative losses in the detector
materials, trigger capability in Au+Au
Z. Xu, BNL LDRD 07-007;L. Ruan et al., Journal of Physics G: Nucl. Part. Phys. 36 (2009) 095001
2010-10-23 STAR Regional Meeting, Ji'nan, China 4
MTD Concept of Design
A detector with long-MRPCs covers thewhole iron bars and leave the gaps in- between uncovered. Acceptance: 45% at ||<0.5
117 modules, 1404 readout strips, 2808 readoutchannels
Long-MRPC detector technology, HPTDCelectronics (same as STAR-TOF)
2010-10-23 STAR Regional Meeting, Ji'nan, China 5
The success of MRPC for STAR TOF
Muon Detector
Time resolution <100ps Efficiency 90%High granularity
2010-10-23 STAR Regional Meeting, Ji'nan, China 6
The multiplicity of muon tracks is quite low To save electronics channels Read out at two ends
Mean time Eliminate the position along the strip Time difference Position information
Easy to build for large area coverage detector
MRPC with Long Strips
2010-10-23 STAR Regional Meeting, Ji'nan, China 7
Gas gaps: 10 x 0.25 mm, in 2 stacks
Glass plates: 0.71 mm
anode
2. First prototype design
Size: 950 x 256 mm2
Read out strip: 25 mm wide, 4 mm gaps between strips
Active area: 870 x 170 mm2
2010-10-23 STAR Regional Meeting, Ji'nan, China 8
Some photos
2010-10-23 STAR Regional Meeting, Ji'nan, China 9
Trigger area: 20 x 5 cm2
Time reference (T0) TOF MRPC was used t
o get 6 segments along the strip.
Gas: 95% Freon + 5% iso-butane HV=±6.4kV
LMRPC
Cosmic ray test
Telescope setup
2010-10-23 STAR Regional Meeting, Ji'nan, China 10
Left end ADC Spectrum Right end ADC SpectrumADC ch ADC ch
Trigger area and ADC spectrum
Cosmic ray test
Trigger area:20 x 5 cm2
STAR TOF MRPC PAD:3.15 x 6.1
cm2
Scheme of the trigger
2010-10-23 STAR Regional Meeting, Ji'nan, China 11
HV plateau
Cosmic ray test
2010-10-23 STAR Regional Meeting, Ji'nan, China 12
signal propagation velocity
Cosmic ray test
TOF MRPC
6 trigger positions along the strip
Time difference of 2 ends vs. position
V-1~59.6±4.9 ps/cm
2010-10-23 STAR Regional Meeting, Ji'nan, China 13
center of the strip
One end of the strip
T-A correlation
T-A correction & Time resolution
Cosmic ray test
2010-10-23 STAR Regional Meeting, Ji'nan, China 14
MWPC5MWPC1 MWPC2
MWPC4
TOF1
252” 73”
TOF2
72” 164”449”
LMRPC
GEMsMWPC3
191”56 3381
TOF370”
Upper stream
Down stream
C1, C2
Beam Energy: 32 GeV
FNAL Beam Test (T963)
Beam test setup
2010-10-23 STAR Regional Meeting, Ji'nan, China 15
Efficiency plateau
FNAL Beam Test (T963)
Time resolution
2010-10-23 STAR Regional Meeting, Ji'nan, China 16
FNAL Beam Test (T963)
Using the tracking, we get the signal propagation velocity:
~ 60ps/cm
The half time difference of 2 ends of a strip:
σΔT/2 ~ 1.1 channel (55ps)
Spatial resolution: ~ 1 cm
Spatial resolution
2010-10-23 STAR Regional Meeting, Ji'nan, China 17
Running in STAR
Run 7 & Run 8
Run 9 & Run 10
2010-10-23 STAR Regional Meeting, Ji'nan, China 18
Run 10 Performance: Time and Spatial Resolution
Cosmic ray trigger:
Total resolution: 109 ps
Start resolution (2 TOF hits): 46 ps
Multiple scattering: 25 ps
MTD intrinsic resolution: 96 ps
System spatial resolution: 2.5 cm, dominated by multiple scattering
L. Li, UT Austin
σ: 109 ps
σ: 2.5 cm
pure muonsaverage pT: ~6 GeV/c
From Lijuan Ruan’s talk at MTD review Sep. 17, 2010
2010-10-23 STAR Regional Meeting, Ji'nan, China 19
Run 9 Performance: Time Resolution
L. Li, UT Austin
σ: 142 ps Include muons from pion, kaon decays and punch-through hadrons
Muon average pT: ~2.5 GeV/c
Total resolution: 142 ps
Start resolution (start detector with TOF electronics readout): 81 ps
Multiple scattering: 70 ps
MTD intrinsic resolution: 94 ps
From Lijuan Ruan’s talk at MTD review Sep. 17, 2010
2010-10-23 STAR Regional Meeting, Ji'nan, China 20
3. Prototype of “real size”
“real size” module: active width ~ 52 cm12 strips: ~4 cm wide Single stack: 6(5) × 0.25 mm gaps
2010-10-23 STAR Regional Meeting, Ji'nan, China 21
Structure — side view
inner glass = 874
Licron electrode = 882
outer glass / honeycomb = 890
PC board = 915
Licron electrode = 551outer glass / honeycomb = 559
PC board = 580
38 6
inner glass = 543
Gas gaps: Prototype I: 250μm × 6Prototype II: 250μm × 5
2010-10-23 STAR Regional Meeting, Ji'nan, China 22
HV plateau of Prototype I (6 gaps)
Adding 2% of SF6 Efficiency: little change Time resolution: improved a lot Quenching the streamer
2010-10-23 STAR Regional Meeting, Ji'nan, China 23
Charge spectrum@±7600V
With more SF6, less streamer achieved.
no SF6 2% SF6 5% SF6
2010-10-23 STAR Regional Meeting, Ji'nan, China 24
Noise rate (Hz/strip)
HV=8000V, Vth=30mV (R134a:C4H10:SF6=93:5:2)
Strip No.
1 2 3 4 5 6 7 8 9 10 11 12
Left 479 253 407 359 310 274 255 252 321 390 259 346
Right
526 280 326 303 163 235 320 266 377 400 280 313
• With HV filter:HV
(+/-) 10MΩ0.5nF
LMRPC
Equivalent to < 1.5 Hz/cm2, comparable to TOF MRPC
2010-10-23 STAR Regional Meeting, Ji'nan, China 25
Prototype II with 5 gaps
Efficiency > 90% over 6300 V Time resolution comparable to Prototype I. (without SF6) Electric field:
kV/cm8.1005cm025.0
2kV3.6
kV/cm7.98
6cm025.0
2kV4.7
5-gap: 6-gap:
2010-10-23 STAR Regional Meeting, Ji'nan, China 26
The first Long-strip MRPCs (10-gap) show very good performance and
were successfully running at STAR from Run7 to Run10. The cosmic ray test :
time resolution: around 70 ps; detection efficiency: higher than 95%.
T963 beam test at FNAL: spatial resolution: less than 1 cm. time resolution and detection efficiency similar to cosmic test
Performance running at STAR: Time resolution <100ps, spatial resolution ~2.5cm
The performances of both “real size” LMRPCs are good enough for the MTD requirements.
Current status: One has been shipped to UT and the other will be shipped out soon. Both to be installed in STAR and running in Run11.
The MTD MRPC mass production project has been approved by NSFC and will start from 2011.
4. Summary
Thank You !