ingo deppnerrpc 2012 workshop, infn, 05 - 10 feb. 2012 1 a mutistrip mrpc prototype for the cbm...

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


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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


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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


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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


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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


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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


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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


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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


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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


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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


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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


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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


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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


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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


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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


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Backup

2 ns Cross talk measurement with a reflectometer


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Backup


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Backup

80 1 ns

ingo deppnerrpc 2012 workshop, infn, 05 - 10 feb. 2012 1 a mutistrip mrpc prototype for the cbm...

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