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Ingo DeppnerDPG-Frühjahrstagung, Mainz, 19 - 23.03.2012 1 A Multistrip-MRPC Prototype for the CBM Time-of-Flight Wall Outline: CBM-ToF requirements Conceptional design of the CBM-ToF wall HD-MRPC design Experimental setup Results Summary / Next steps Ingo Deppner for the CBM-TOF Group Physikalisches Institut Uni. Heidelberg DPG – Frühjahrstagung 2012
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Ingo DeppnerDPG-Frühjahrstagung, Mainz, 19 - 23.03.2012 2 Motivation 80 120 1 ns RPC twisted pair cabe feed through gas box CBM-ToF Requirements Full system time resolution T ~ 80 ps Efficiency > 95 % Rate capability 25 kHz/cm 2 Polar angular range 2.5° – 25° Occupancy < 5 % (for Au-Au(central) at E = 25 AGeV) Low power electronics (~75.000 channels) Pile-up < 5% Compressed Baryonic Matter Experiment at FAIR facility @ GSI Interaction rate 10 MHz Charged hadron identification is provided by Time-of-Flight (ToF) measurement Central Au+Au collision @ 25 AGeV, UrQMD + GEANT 160 p, 400 +, 400 -, 44 K +, 13 K -
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Ingo DeppnerDPG-Frühjahrstagung, Mainz, 19 - 23.03.2012 3 Conceptional Design Timing RPC with: active area: A = 120 m 2 counter time resolution: T ~ 50 ps rate capability: R ~ 0.5 – 25 kHz/cm 2 granularity: A ~ 6 – 50 cm 2 operation mode: free running (see talk of P.-A. Loizeau HK 34.6 ) Rate profile (Au-Au(minimum bias) at E=25 GeV/A) kHz/cm 2 A. Kiseleva, P.-A. Loizeau 44 SM (55%) have a rate < 1 kHz/cm 2
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Ingo DeppnerDPG-Frühjahrstagung, Mainz, 19 - 23.03.2012 4 Conceptional Design 1 Super Module 1 ns 1,5 m 1,0 m RPC 1 RPC 2 RPC 3 RPC 4 RPC 5 RPC 6 Region: A, B, C, D, E RPC electrode material A: float (window) glass B: semi conductive glass C: semi conductive glass D: semi conductive glass E: ceramics (see talk of A. Laso Garcia HK 4.5 )
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Ingo DeppnerDPG-Frühjahrstagung, Mainz, 19 - 23.03.2012 5 HD-MRPC design HD- MMRPC fully symmetric and differential active area 32 x 27 cm 2 strips32 strip / gap 7 / 3 mm glass typefloat glass glass thickness0.5 mm number of gaps8 gap width 220 m impedance100 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. M4 plastic screw Pickup electrode transmission line with 2 x 50 imp- edance to ground impedance of 100 connector to preamp. (PADI) or twisted pair cable cross section of the HD counter RPC in gas tight aluminum box RPC side view
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Ingo DeppnerDPG-Frühjahrstagung, Mainz, 19 - 23.03.2012 6 Experimental setup Test beam time @ COSY accelerator Jülich, Germany in Nov. 2011 with protons of 2,5 GeV Heidelberg RPC 4 front PMTs 2 back PMTs 2 RPCs from Tsinghua Univ., China 2 RPCs from NIPNE Romania 2 RPCs from HZDR Germany Hodoscope warmed-up backplane beam Beam profile extracted from Hodoscope is used for rate estimation beam area about 0,4 cm 2 vertical scintillator horizontal scintillator Ref. RPC NIPNE
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Ingo DeppnerDPG-Frühjahrstagung, Mainz, 19 - 23.03.2012 7 Results Mean cluster size is defined as the average number of neighboring strips firing simultaneously HV = 11.5 kV Thr. = 30 mV
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Ingo DeppnerDPG-Frühjahrstagung, Mainz, 19 - 23.03.2012 8 Results 95% HV = 11.5 kV Thr. = 30 mV HV = 11.3 kV rate < 500 Hz/cm 2 directly connected preamps allow for lowering the threshold by 5 mV
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Ingo DeppnerDPG-Frühjahrstagung, Mainz, 19 - 23.03.2012 9 Results dt = t Buc-RPC – t HD-RPC dt / channel counts dt spectrum dt = 71.5 ps Considering equal time resolution for both MRPC‘s the time resolution for the indivi- dual RPC including the contribution of the electronics is about 51 ps 15,4 kHz/cm² 21,9 kHz/cm² 17,3 kHz/cm² 17,6 kHz/cm² increasing the temperature by 20°C improves the rate capability by 1 order of magnitude HV = 11.3 kV Thr. = 30 mV R 100 Hz/cm 2 RPC 51 ps
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Ingo DeppnerDPG-Frühjahrstagung, Mainz, 19 - 23.03.2012 10 Summary At the Physikalisches Institut of Heidelberg University we developed a MMRPC prototype for the low rate region (below 1 kHz/cm 2 ) for CBM This prototype was successfully tested with pions at SIS18 at GSI / Darmstadt and with protons 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 the 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 Next steps Further beam tests under full surface illumination condition Building a full size demonstrator
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Ingo DeppnerDPG-Frühjahrstagung, Mainz, 19 - 23.03.2012 11 Next steps Full size demonstrator RPC fully differential active area 52 x 54 cm 2 PCB size 56 x 60 cm 2 (maximal size) strips52 strip / gap 7 / 3 mm glass typefloat glass glass thickness0.5 mm number of gaps8 - 9 gap width 220 m PADI board with 4 channel input (under developmet) transmission line with 2 x 50 imp- edance to ground connector to a 4 ch. PADI 5 cm 200 k SMD resistor to ground 5 cm Super module # RPCs: 6 # strips: 312 # PADI (4 ch.) : 156 # channels: 624 total active area: 152 cm x 104 cm overlap h: 4 cm v: 2 cm box size (inside) 170 cm x 130 cm x 14 cm
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Ingo DeppnerDPG-Frühjahrstagung, Mainz, 19 - 23.03.2012 12 thank you for your attention Contributing institutions: Tsinghua Beijing, NIPNE Bucharest, GSI Darmstadt, USTC Hefei, PI Heidelberg, KIP Heidelberg, INR Moscow, ITEP Moscow, IHEP Protvino, HZDR Rossendorf, KU Seoul, CCNUWuhan, RBI Zagreb Special thanks goes to: Norbert Herrmann, Jochen Frühauf, Pierre Alain Loizeau, Krzysztof Wisniewski, Changzhou Xiang
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Ingo DeppnerDPG-Frühjahrstagung, Mainz, 19 - 23.03.2012 13 Backup 80 1 ns Backup Slides
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Ingo DeppnerDPG-Frühjahrstagung, Mainz, 19 - 23.03.2012 14 CBM Physics topics Deconfinement / phase transition at high ρ B QCD critical endpoint The equation-of-state at high ρ B chiral symmetry restoration at high ρ B 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) Backup non twisted part connector p K D. Kresan Au + Au @ 25GeV Kaon acceptance depends critically on TOF resolution bulk observables and rare probes
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Ingo DeppnerDPG-Frühjahrstagung, Mainz, 19 - 23.03.2012 15 Backup
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Ingo DeppnerDPG-Frühjahrstagung, Mainz, 19 - 23.03.2012 16 Backup 80 1 ns
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