Ingo Deppner RPC 2012 Workshop, INFN, 05 - 10 Feb. 2012
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A Mutistrip MRPC prototype for the CBM Time-of Flight wall
Outline:• Motivation / CBM-ToF Requirements• Conceptional Design• HD-MRPC design• Experimental setup• Results• Summary / Next steps
Ingo Deppner for the CBM-TOF GroupPhysikalisches Institut Uni. Heidelberg
RPC 2012 – XI Workshop on Resistive Plate Chambers and Related
Detectors
Ingo Deppner RPC 2012 Workshop, INFN, 05 - 10 Feb. 2012
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Motivation
80
120
1 ns
RPCtwisted pair cabe
twisted pair cabe
feed throughgas box CBM-ToF Requirements
full system time resolution T ~ 80 ps Efficiency > 95 % Rate capability 25 kHz/cm2
Acceptable cross-talk and charge-sharing. Polar angular range 2.5° – 25° Low power electronics (~75.000 channels). Pile-up < 5% Occupancy < 5 % (for Au-Au(central) at E=25 GeV/A)
Phase diagram of strongly interacting matter Compresed Barionic Matter Experimen at FAIR facility
@ GSI
bulk observables and rare probes
Interaction rate 10 MHz
Ingo Deppner RPC 2012 Workshop, INFN, 05 - 10 Feb. 2012
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Conceptional Design
Timing RPC with: active area: A = 120 m2
counter time resolution: T ~ 50 ps rate capability: R ~ 0.5 – 25 kHz/cm2
granularity: A ~ 6 – 50 cm2
operation mode: free running (see talk of P.-A. Loizeau on Friday)
Rate profile (Au-Au(minimum bias) at E=25 GeV/A)
kHz/cm2A. Kiseleva, P.-A. Loizeau
44 SM (55%) have a rate < 1 kHz/cm2
Ingo Deppner RPC 2012 Workshop, INFN, 05 - 10 Feb. 2012
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80
120
1 ns
Conceptional Design
1,5 m
1,0
m
RPC 1 RPC 2 RPC 3
RPC 4 RPC 5 RPC 6
1 Super Module
Ingo Deppner RPC 2012 Workshop, INFN, 05 - 10 Feb. 2012
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HD-MRPC design
MMRPC fully symmetric and differentialactive area 32 x 27 cm2
strips 32strip / gap 7 / 3 mmglass type float glassglass thickness 0.5 mm number of gaps 8gap width 220 m
pick-up electrode (green)Kapton foil (orange)HV electrode (blue)glass plates (light blue)HV electrode (blue)Kapton foil (orange)pick-up electrode (green)
honeycomb st.
connectorto a wisted pair cable or to the preamplifier
Electrode structure
honeycomb st.
side view
front view
front view
side view
200 k SMD resistor to
groundtransmission line with 2 x 50 imp-edance to ground
connector to PADI
impedance of 100 M4 plastic
screw
Ingo Deppner RPC 2012 Workshop, INFN, 05 - 10 Feb. 2012
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HD-MRPC design
Pickup electrode
HV electrode
PADI connected directly to the RPC
mounting in clean room @GSI RPC side view
RPC in gas tight aluminum box
Ingo Deppner RPC 2012 Workshop, INFN, 05 - 10 Feb. 2012
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Technical properties
Signal rise time measurement Reflectometer measurement
0 200 400 600 rise time [ps]
2 ns
RPCtwisted pair cabe
twisted pair cabe
non twisted part
connector
feed throughgas box
Impedance about 93
mean rise time 208 ps
Ingo Deppner RPC 2012 Workshop, INFN, 05 - 10 Feb. 2012
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Experimental setup
Test beam time @ COSY accelerator Jülich, Germany in Nov. 2011 with protons of 2,5 GeV
HeidelbergRPC
4 front PMTs 2 back
PMTs
2 RPCs from Tsinghua
Univ., China
3 RPCs from NIPNE
Romania
2 RPCs from HZDR
Germany
Hodoscopewarmed-up backplane
beam
Beam profile extracted from Hodoscope is used for rate
estimation
beam area about 0,4 cm2
vertical scintillator
horizontal scintillator
Ingo Deppner RPC 2012 Workshop, INFN, 05 - 10 Feb. 2012
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Results
95%
HV = 11.5 kVThr. = 30 mV
HV = 11.3 kVrate < 500 Hz/cm2
directly connected
preamps allow for lowering
the threshold by 5 mV
Ingo Deppner RPC 2012 Workshop, INFN, 05 - 10 Feb. 2012
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Results
Mean cluster size is defined as the average number of neighboring strips firing simultaneously
HV = 11.5 kVThr. = 30 mV
HV = 11.5 kVThr. = 30 mV
Ingo Deppner RPC 2012 Workshop, INFN, 05 - 10 Feb. 2012
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Results
dt = tBuc-RPC – tHD-RPC
dt [channel]
coun
ts
dt spectrum
t = 71.5 ps
Considering equal time resolution for both MRPC‘s the
time resolution for the individual RPC is about 51 ps
Ingo Deppner RPC 2012 Workshop, INFN, 05 - 10 Feb. 2012
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Summary
Summary At the Physikalisches Institute of the Heidelberg University we developed a MMRPC prototype for the low rate region (below 1 kHz/m2) for CBMThis prototype was successfully tested with pions and protons at SIS18 at GSI / Darmstadt and at the COSY accelerator in Jülich Based on these in-beam tests we can show that an efficiency above 95% was reached for preamplifier thresholds below 30 mV Results obtained from the electronics mounted directly on the RPC indicate a higher stability in terms of noise and signal reflections Warming up the RPC environment by 15 °C seems to be enough in order to fulfill the CBM - TOF requirement of he outer region The mean cluster size for this prototype is in the order of 1.3 and growing with temperature Time resolution is in the order of 50 ps
Ingo Deppner RPC 2012 Workshop, INFN, 05 - 10 Feb. 2012
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Next stepsFull size demonstratorRPC fully differentialactive area 52 x 54 cm2
PCB size 56 x 60 cm2 (maximal size)strips 52strip / gap 7 / 3 mmglass type float glassglass thickness 0.5 mm number of gaps 8 - 9gap width 220 mPADI board with 4 channel input(under developmet)
transmission line with 2 x 50 imp-edance to ground
connector to a 4 ch.
PADI5 cm 200 k SMD
resistor to ground
5 cm
Super module# RPCs: 6 # strips: 312# PADI (4 ch.) : 156# channels: 624total active area: 152 cm x 104 cmoverlap h: 4 cm v: 2 cmbox size (inside)170 cm x 130 cm x 14 cm
Ingo Deppner RPC 2012 Workshop, INFN, 05 - 10 Feb. 2012
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Contributing institutions:Tsinghua Beijing,NIPNE Bucharest,GSI Darmstadt,USTC Hefei,PI Heidelberg,KIP Heidelberg,INR Moscow,ITEP Moscow,IHEP Protvino,HZDR Rossendorf,KU Seoul,CCNU WuhanRBI Zagreb.
thank you for your attention
Special thanks goes to:
Norbert Herrmann,Jochen Frühauf,Pierre Alain Loizeau,Changzhou Xiang
Ingo Deppner RPC 2012 Workshop, INFN, 05 - 10 Feb. 2012
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CBM Physics topics Deconfinement / phase transition at high ρB
QCD critical endpoint The equation-of-state at high ρB
chiral symmetry restoration at high ρB
Observables excitation function and flow of strangeness and charm collective flow of hadrons particle production at threshold energies excitation function of event-by-event fluctuations excitation function of low-mass lepton pairs in-medium modifications of hadrons (ρ,ω,φ → e+e-(µ+µ-), D)
In order to measure all these observables with an high accuracy, we need a good
particle identification
Backup
non twisted part
connector
pK
D. Kresan Au + Au @ 25GeV
Kaon acceptance depends critically on TOF resolution
Ingo Deppner RPC 2012 Workshop, INFN, 05 - 10 Feb. 2012
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Backup
2 ns Cross talk measurement with a reflectometer
Ingo Deppner RPC 2012 Workshop, INFN, 05 - 10 Feb. 2012
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Backup
Ingo Deppner RPC 2012 Workshop, INFN, 05 - 10 Feb. 2012
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Backup
80 1 ns