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Zebo Tang University of Science and Technology of China (USTC)

MRPC-TOF R&D, calibration, performance and related physics at STAR. Zebo Tang University of Science and Technology of China (USTC). Outline. Introduction STAR MRPC-TOF R&D Calibration Performance PID and physics results achieved Summary & Outlook. STAR Detector.

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Zebo Tang University of Science and Technology of China (USTC)

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  1. MRPC-TOF R&D, calibration, performance and related physics at STAR Zebo Tang University of Science and Technology of China (USTC) Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  2. Outline • Introduction • STAR MRPC-TOF R&D • Calibration • Performance • PID and physics results achieved • Summary & Outlook Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  3. STAR Detector Large acceptance: 2 coverage at mid-rapidity Magnet Coils Central Trigger Barrel (CTB) ZCal Time Projection Chamber (TPC) Year 2000 Barrel EM Cal (BEMC) Silicon Vertex Tracker (SVT)Silicon Strip Detector (SSD) FTPCEndcap EM CalFPD TOFp, TOFr PMD Year 2001+ Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  4. GeV/cm 200 GeV Au+Au Resolution ~8% p K p e Why do we need a TOF? Specific Energy Loss in STAR TPC With the STAR TPC K p identification: p ~ 0.7 GeV/c Proton identification: p ~ 1.1 GeV/c S/N for f reconstruction: ~ 1/few 100 Multi-strange particles reconstruction efficiency: ~ 10-4 --10-3 Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  5. TOF PID Capability (~220 cm from the Beam Line) R. Majka for STAR Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  6. Characteristic length: balance function, strangeness correlation What can TOF do at STAR? Baryon Transport: net baryons E-by-E Gluon Dynamics: K/p, p/p Dynamical Fluctuations: p/K/p Separation TOF Huan Huang Particle Composition Bulk Property: CGC? Evolution Dynamics Particle Correlations Exotic Particle Searches Elliptic Flow: p/K/p/L/f/X/W Heavy Quark: D,J/y HBT: pp, KK Jet Fragmentation: Baryon-meson PID Resonance:K*,r,D L(1520),S(1385),X(1530) Nucleosynthesis: 3He/t Di-baryon: H or L-L,W-W,[Xp] Unlike Particles: pK, pp and Kp. Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  7. Requirements 1) Good Time resolution The total resolution after all corrections must be <100 ps,for a start time resolutionof ∼50 ps, 30 ps contribution from slew correction, pure stop resolution of less than ∼80 ps. 2) High Granularity（dN/dy~1000 in central Au+Au) The detector segmentation must be such that the occupancy per channel is < 10%. 3) The system must be able to operate at particle fluxes up to ∼200 Hz/cm2. 4) The system must be able to operate inside the STAR magnetic field. 5) The system must fit into the integration envelope for the present CTB . 6) The system must be inexpensive Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  8. The Multi-Gap Resistive Plate Chamber MRPC is a good choice First suggested by C. Williams et al for ALICE TOF Uniform High Electric Field ~11kV/mm high drift velocity ~220m/ns high Townsend coefficient. Operate in Avalanche mode Gas: Freon (electron affinity ) iso-butane (UV photon absorption) SF6 (streamer suppressing) Heavy gas: 9-10clusters/mm for MIP Small gap: 0.2-0.3 mm, high resolution Multi-gaps: high efficiency E. Gorini et al. Nucl. Instr. Meth. A 396(1997), 93 Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  9. MRPC R&D • Single pad MRPC • 4×4 cm2 • 5×0.22mm gas gap b) 12-pads MRPC 7×20cm2 6×0.25mm gas gaps pad size: 3.1×3 cm2 c) 6-pads 7×21cm2 10×0.25mm gas gaps pad size: 6×3.1cm2 Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  10. Beam Test Results Cheng Li et al., NST, V13N1 Single pad, 5 gaps Efficiency:Time resolution: >~95% (6 gaps)~70ps (5 gaps) ~99% (2×5 gaps)~60ps (6 gaps) ~50ps (2×5 gaps) Counting rates range :< 500Hz/cm2(with normal float glass) Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  11. A prototype at STAR (2002+) 24 out of 28 modules made in USTC, China Covers 6 in azimuth and 1 in pseudo-rapidity,at radius ~ 2.2 m 1/120 of total coverage Module: 20×6 cm Gap：6×0.22 mm Pad：3.15cm×6.1cm Gas：95% C2H2F4 +5% Iso-C4H10 Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  12. Timing Resolution before Calibration Resolution = 124 ps Calibration is necessary Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  13. Electronics (2005+) 2 THUB per side, 4 total 1 TCPU per tray/pVPD, 122 total 1 TPMT/TDIS per pVPD, 2 total 8 TINO/TDIG per tray, 960 total 24 chn. per TINO/TDIG, 23040 total Schambach Jo et al., Int. J. Mod. Phys. E 16 2496 Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  14. 2.7 0.9 HPTDC INL Correction Integral Non-Linearity DifferentialNon-Linearity Jing Liu Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  15. Leading-edge trigger, signal charge (ADC) is measured for correction Amp. Q1 Thre. Q2 T1T2 time Time-TOT Correlation Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  16. beam Scan area Signal output Hit Position Correction propagation speed：~45ps/cm Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  17. TOFr Calibration procedure • Choose  sample by limiting dE/dx and momentum range (or pre-calibrated TOF) • T0 correction,different cable length and signal transition time • TOFr TOT and Z position calibration, using charged pion sample. • Iteration several times (if needed) • Try channel-by-channel first • Not enough statistics? Then try module-by-module, or board-by-board Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  18. 2005 Cu+Cu, 62 GeV 2005 Cu+Cu, 200 GeV 2008 p+p, 200 GeV 2009 p+p, 500 GeV TOF Timing Resolution Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  19. TOF Time Resolution Summary Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  20. Hadron PID TPC alone: /k ~0.7 GeV/c, (,k)/p ~1.1 GeV/c TPC p K π TOF e TOF alone:  /k ~1.6 GeV/c, (,k)/p ~ 3.0 GeV/c STAR Collaboration, PLB 616 (2005) 8 Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  21. Au+Au TPC only p+p With ONE TOF Prototype STAR, PLB 616, 8 (2005); PRL 97, 152301 (2006) Light hadron with TOF STAR PRL92,112301 (2004) Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  22. |1/β-1|<0.03 Electron and muon ID Electron: pT>0.2 GeV/c Muon: pT<0.25 GeV/c STAR, PRL 94, 062301, (2005) arXiv: 0805.0364 Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  23. Heavy Flavor with TOF D0Kp m e arXiv: 0805.0364 Very helpful for open charm and hidden charm physics Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  24. Light Nuclei with TOF Haidong Liu (STAR Collaboration), JPG 34, S1087 (2006), QM2006 Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  25. Resonance with TOF Au+Au 200GeV Only one TOF track Enhanced by a factor of ~4 Yichun Xu et al., NIM A596, 186 (2008) Enhanced by a factor of ~2 Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  26. New Type MRPC-TOF R&D 1) Long Strip MRPC-TOF 2) High Resolution MRPC-TOF Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  27. 95 cm 25 cm Long-strip MRPC R&D LMRPC Pad size of STAR TOF 2.5 cm Suitable for: 1) Muon Telescope Detector @ STAR 2) TOF wall @ CBM Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  28. Beam Test Results Yongjie Sun et al., NIM, A593, 307 (2008) Time resolution Plateau Efficiency Plateau At E~100 kV/cm (HV=±6300 V): Efficiency ~98% Resolution <70 ps Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  29. Beam Test Results Yongjie Sun et al., NIM, A593, 307 (2008) • Signal propagation velocity: ~ 60ps/cm • The time difference: s(T) ~55ps • Position resolution: ~ 1 cm Position calculated from timing on two ends USTC module, HV=6300V, run30-33 Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  30. High Resolution MRPC R&D Cheng Li Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  31. Beam Test Results of a 24-gaps MRPC ~21 ps Shaohui An et al., NIM A594, 39-43 (2006) Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  32. Summary and Outlook • The Advantage of MRPC-TOF: • good timing resolution (<80 ps) • high efficiency (>90%) • cost effective for large area TOF system • A prototype of TOF in STAR works very well: • Satisfied all of the requirements • Very helpful for identifying hadrons, leptons, light nuclei and resonances, achieved lots of important physics results. • 75% has been installed in STAR, 100% in 2010 • A strong team at USTC is formed R&D, mass production, software, calibration, physics analysis • We are keeping working on new MRPC-TOFs R&D • Long strip MRPC • High resolution MRPC Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  33. Extra slides Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  34. Start Detector -VPD W.J. Llope Collision Point • All hits in the same event arrived at the same time • As reference for each other VPD PMTs Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  35. TOF calibration w/o start detector Fast simulation Single channel resolution: 90ps Time-TOT/Z correlation taken from real data T0 obtained by direct average of Ti 6 iteration of calibration Expectation (ideal) Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  36. T0 resolution w/o start detector – from data Run V 62.4 GeV CuCu After 6-round calibration iteration Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

  37. Leading-edge timing signal, trailing-edge signal width (TOT) Leading-edge trigger, signal charge (ADC) is measured for correction Amp. Amp. Q1 Thre. Thre. Q2 T1lT2l T2tT1t time T1T2 time Time stamp Time-TOT Correlation Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

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