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Status of TOF Calibration and the future

Status of TOF Calibration and the future. Framework Calibration w/o tracking PID Calibration with tracking Performance Summary. Akio Kiyomichi Univ. of Tsukuba Tsukuba-Yonsei Workshop December 5, 2000. Basic Design. Scintillator: 1.5 x1.5x64cm. Timing Pulse Height. PMT.

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Status of TOF Calibration and the future

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  1. Status of TOF Calibration and the future Framework Calibration w/o tracking PID Calibration with tracking Performance Summary Akio Kiyomichi Univ. of Tsukuba Tsukuba-Yonsei Workshop December 5, 2000

  2. Basic Design Scintillator: 1.5x1.5x64cm Timing Pulse Height PMT • Scintillator: Bicron BC404 • decay constant : 1.8 ns • attenuation length : 160cm • PMT : Hamamatsu R3478S • rise time : 1.3 ns • transit time : 14 + - 0.36 ns • HV Bleeder with chip resisters 80 ps 1.3 cm Akio Kiyomichi [Univ. of Tsukuba]

  3. TOF Performance at CERN-WA98 • 5 panels of TOF tested at CERN-WA98. • Overall TOF resolution of < 85ps obtained. • sTOF counter ~80ps + sStart counter ~30ps • For PHENIX, we will reach TOF resolution <95ps. • sTOF counter ~80ps + sBBC counter ~50ps s ~ 85ps Time-of-Flight [ns] (1996) Used high momentum p TOF resolution for all 500 slats Akio Kiyomichi [Univ. of Tsukuba]

  4. Taking account 8/9 parameter so far Calibration Framework 9 TOF parameter set • Time offset • Slewing parameter • Y position offset • Light velocity in scint. • Energy loss conversion factor • Time conversion factor • Charge conversion factor • TVC/QVC pedestal • Global Time offset PRDF TofCalibrator PASS:0 rough calibration CAMERA reconstruction PASS:1~ calibration w/ tracking DST Akio Kiyomichi [Univ. of Tsukuba]

  5. Rough Calibration: Zero-field Run • Rough calibration parameters obtained. [~200ps level] • T0 value and Z-vertex information from BBC. • NO tracking information used yet. (To be done) • Timing offset, Position offset and Gain Correction y position offset Time offset Dt = 5 nsec ~ length of scinti. 64cm Calibration condition • BBC Z vertex (-40 < z < 40 cm) are required • L : straight path ( from z-vertex TOF hit • position with retracted geometry) • Including BBC Coins, ZDC coins, • BBC&ZDC trigger Akio Kiyomichi [Univ. of Tsukuba]

  6. Track matching and TOF intrinsic timing resolution • sTOF-TEC = 2cm: • Corresponding timing resolution is 120 ps. • Consistent with TOF intrinsic timing resolution of 120ps operated without slewing correction. sposition ~ 2cm sTIME ~ 120 ps TOF PC3 TEC Akio Kiyomichi [Univ. of Tsukuba]

  7. Particle Identification • We can see clear p,K,p separation • No slewing correction • No final timing adjustment Akio Kiyomichi [Univ. of Tsukuba]

  8. TOF resolution (before New calibration) • Select High-momentum pion. • Current Time of Flight resolution is ~170ps. • BBC, TOF, Tracking Chamber • No slewing correction yet. • No final adjustment of relative timing offset yet. s ~ 170 ps Akio Kiyomichi [Univ. of Tsukuba]

  9. TOF Calibration Passes • Calibration w/o Tracking • pass0: Rough Calibration • Calibration with Tracking(p selection for timing calibration) • pass1: Y-position offset • pass2: Rough Timing offset • pass3: Slewing correction • pass4: Timing offset [slat by slat] • *pass5: more adjustment position offset • *pass6: Timing offset [run by run] Akio Kiyomichi [Univ. of Tsukuba]

  10. Used DST data • phs5 + projection • Run 10726 -12087 (~500K event) • Statistics: 200~500 hits per slat • dch_quality>20 • dR < 5cm cut • phs5+projection • 0.1 < m2 < 0.1 (pion) for Timing calibration Akio Kiyomichi [Univ. of Tsukuba]

  11. pass1: Y-position offset • Estimate Y-position offset and Light Velocity. • Light Velocity ~15cm/ns • Y-position offset Akio Kiyomichi [Univ. of Tsukuba]

  12. pass2: Rough Timing offset • Estimate Time offset value based on the pion selection [slat by slat] • Difference between new and old • 1ns(peak-edge) + 1.4ns(BBC Time-offset) Akio Kiyomichi [Univ. of Tsukuba]

  13. pass3: Slewing correction • We use leading edge discriminator. • Fitting function: y = A + B/sqrt(x) • Estimate slewing parameters (A,B) • Typical value for WA98 • A = -0.4~ -0.27 ,B = 11~21 Akio Kiyomichi [Univ. of Tsukuba]

  14. pass4: Timing offset • Estimate Time offset value based on the pion selection after slewing correction [slat by slat] Akio Kiyomichi [Univ. of Tsukuba]

  15. Performance • Use recent DST (product in Dec.1 - 4) • about 100 files : ~100K event • Select high momentum pion+ • dR<5cm, 0.05<m2<0.1, pt>1.5GeV/c • TOF - T0(BBC)*0.975 - flighttime(Tracking) • close to achieve <100ps !? s< 110ps Akio Kiyomichi [Univ. of Tsukuba]

  16. Future plan / known problem • We will get DSTs for whole runs in few weeks. • ~5M event • We should try • Check Run dependence • BBC/TOF timing conversion factor. • Slewing correction using more statistics. Timing conversion factor gap Akio Kiyomichi [Univ. of Tsukuba]

  17. Summary • Calibration code is now available. • We can do iterative process from DST. • Taking account 8/9 parameters. • Only global time offset is still 0 value. • It will check by next DST. • TOF resolution reach < 110 ps in recent DST.(very preliminary) Akio Kiyomichi [Univ. of Tsukuba]

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