RPC 2012 XI Workshop on Resistive Plate Chambers

RPC 2012 – XI Workshop on Resistive Plate Chambers and Related Detectors A Mutistrip MRPC prototype for the CBM Time-of Flight wall Ingo Deppner for the CBM-TOF Group Physikalisches Institut Uni. Heidelberg Outline: • Motivation / CBM-To. F Requirements • Conceptional Design • HD-MRPC design • Experimental setup • Results • Summary / Next steps Ingo Deppner RPC 2012 Workshop, INFN, 05 - 10 Feb. 2012

Motivation Phase diagram of strongly interacting matter Compresed Barionic Matter Experimen at FAIR facility @ GSI bulk observables and rare probes CBM-To. F Requirements Ø full system time resolution s. T ~ 80 ps Ø Efficiency > 95 % Ø Rate capability 25 k. Hz/cm 2 Ø Acceptable cross-talk and charge-sharing. Ø Polar angular range 2. 5° – 25° 120 WØ Low power electronics (~75. 000 channels). Ø Pile-up < 5% 80 W Ø Occupancy < 5 % 1 ns (for Au-Au(central) at E=25 Ge. V/A) Ingo Deppner twisted pair cabe feed through RPC twisted pair cabe Interaction gas boxrate 10 MHz RPC 2012 Workshop, INFN, 05 - 10 Feb. 2012

Conceptional Design Timing RPC with: Ø active area: A = 120 m 2 Ø counter time resolution: s. T ~ 50 ps Ø rate capability: R ~ 0. 5 – 25 k. Hz/cm 2 Ø granularity: DA ~ 6 – 50 cm 2 Ø operation mode: free running (see talk of P. -A. Loizeau on Friday) Rate profile (Au-Au(minimum bias) at E=25 Ge. V/A) 44 SM (55%) have a rate < 1 k. Hz/cm 2 Ingo Deppner A. Kiseleva, P. -A. Loizeau RPC 2012 Workshop, INFN, 05 - 10 Feb. 2012 k. Hz/cm 2

Conceptional Design 1 Super Module RPC 2 RPC 3 RPC 4 RPC 5 RPC 6 1, 0 m RPC 1 120 W 80 W 1 ns Ingo Deppner 1, 5 m RPC 2012 Workshop, INFN, 05 - 10 Feb. 2012

HD-MRPC design MMRPC active area strips strip / gap glass type glass thickness number of gaps gap width fully symmetric and differential 32 x 27 cm 2 32 7 / 3 mm float glass 0. 5 mm 8 220 mm front view honeycomb st. M 4 plastic screw connector to a wisted pair cable or to the preamplifier Ingo Deppner front view Electrode structure side view pick-up electrode (green) Kapton foil (orange) HV electrode (blue) glass plates (light blue) HV electrode (blue) Kapton foil (orange) pick-up electrode (green) side view transmission line with 2 x 50 W impedance to ground impedance of 100 W honeycomb st. RPC 2012 Workshop, INFN, 05 - 10 Feb. 2012 200 k. W SMD resistor to ground connector to PADI

HD-MRPC design HV electrode Pickup electrode RPC side view mounting in clean room @GSI PADI connected directly to the RPC Ingo Deppner RPC in gas tight aluminum box RPC 2012 Workshop, INFN, 05 - 10 Feb. 2012

Technical properties Signal rise time measurement Reflectometer measurement 2 ns non twisted part twisted pair cabe 0 200 400 600 rise time [ps] connector RPC twisted pair cabe feed through gas box Impedance about 93 W mean rise time 208 ps Ingo Deppner RPC 2012 Workshop, INFN, 05 - 10 Feb. 2012

Experimental setup Test beam time @ COSY accelerator Jülich, Germany in Nov. 2011 with protons of 2, 5 Ge. V Heidelberg RPC 4 front PMTs 2 RPCs from Tsinghua Univ. , China 2 RPCs from HZDR Germany 3 RPCs from NIPNE Romania Beam profile extracted from Hodoscope is used for rate estimation vertical scintillator 2 back PMTs horizontal scintillator beam warmed-up backplane beam area about 0, 4 cm 2 Hodoscope Ingo Deppner RPC 2012 Workshop, INFN, 05 - 10 Feb. 2012

Results 95% HV = 11. 5 k. V Thr. = 30 m. V Ingo Deppner directly connected preamps allow for lowering the threshold by 5 m. V HV = 11. 3 k. V rate < 500 Hz/cm 2 RPC 2012 Workshop, INFN, 05 - 10 Feb. 2012

Results HV = 11. 5 k. V Thr. = 30 m. V Mean cluster size is defined as the average number of neighboring strips firing simultaneously Ingo Deppner RPC 2012 Workshop, INFN, 05 - 10 Feb. 2012

Results counts dt spectrum st = 71. 5 ps Considering equal time resolution for both MRPC‘s the time resolution for the individual RPC is about 51 ps dt [channel] dt = t. Buc-RPC – t. HD-RPC Ingo Deppner RPC 2012 Workshop, INFN, 05 - 10 Feb. 2012

Summary Ø At the Physikalisches Institute of the Heidelberg University we developed a MMRPC prototype for the low rate region (below 1 k. Hz/m 2) for CBM ØThis prototype was successfully tested with pions and protons at SIS 18 at GSI / Darmstadt and at the COSY accelerator in Jülich Ø Based on these in-beam tests we can show that an efficiency above 95% was reached for preamplifier thresholds below 30 m. V Ø Results obtained from the electronics mounted directly on the RPC indicate a higher stability in terms of noise and signal reflections Ø Warming up the RPC environment by 15 °C seems to be enough in order to fulfill the CBM - TOF requirement of he outer region Ø The mean cluster size for this prototype is in the order of 1. 3 and growing with temperature Ø Time resolution is in the order of 50 ps Ingo Deppner RPC 2012 Workshop, INFN, 05 - 10 Feb. 2012

Next steps Full size demonstrator 5 cm transmission line with 2 x 50 W impedance to ground connector to a 4 ch. PADI 200 k. W SMD resistor to ground RPC fully differential active area 52 x 54 cm 2 PCB size 56 x 60 cm 2 (maximal size) strips 52 strip / gap 7 / 3 mm glass type float glass thickness 0. 5 mm number of gaps 8 - 9 gap width 220 mm PADI board with 4 channel input (under developmet) 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 Ingo Deppner RPC 2012 Workshop, INFN, 05 - 10 Feb. 2012

thank you for your attention Contributing institutions: Tsinghua NIPNE GSI USTC PI KIP INR ITEP IHEP HZDR KU CCNU RBI Beijing, Bucharest, Darmstadt, Hefei, Heidelberg, Moscow, Protvino, Rossendorf, Seoul, Wuhan Zagreb. Ingo Deppner Special thanks goes to: Norbert Herrmann, Jochen Frühauf, Pierre Alain Loizeau, Changzhou Xiang RPC 2012 Workshop, INFN, 05 - 10 Feb. 2012

Backup D. Kresan Au + Au @ 25 Ge. V CBM Physics topics Ø Deconfinement / phase transition at high ρB Ø QCD critical endpoint Ø The equation-of-state at high ρB Ø chiral symmetry restoration at high ρB p non twisted part K p connector Kaon acceptance depends critically on TOF resolution Observables In order to measure all these Ø excitation function and flow of strangeness and charm observables with an high accuracy, we need a good Ø collective flow of hadrons particle identification Ø particle production at threshold energies Ø excitation function of event-by-event fluctuations Ø excitation function of low-mass lepton pairs Ø in-medium modifications of hadrons (ρ, ω, φ → e+e-(µ+µ-), D) Ingo Deppner RPC 2012 Workshop, INFN, 05 - 10 Feb. 2012