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BESIII 宇宙线实验

BESIII 宇宙线实验. 朱科军 高能物理研究所. BEPCII Project. Luminosity: 3~10×10 32 cm -2 s -1 @ 3.77GeV. Milestones. Barrel EMC and electronics was ready on 11/30/2007 Trigger system for EMC was ready on 11/30/2007 Started MUON test since 12/3/2007 Barrel TOF and electronics was ready on 12/20/2007

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BESIII 宇宙线实验

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  1. BESIII宇宙线实验 朱科军 高能物理研究所

  2. BEPCII Project Luminosity: 3~10×1032cm-2s-1 @ 3.77GeV

  3. Milestones • Barrel EMC and electronics was ready on 11/30/2007 • Trigger system for EMC was ready on 11/30/2007 • Started MUON test since 12/3/2007 • Barrel TOF and electronics was ready on 12/20/2007 • MDC and electronics was ready on 1/2/2008 • Cosmic ray w/o end-cap seen on 1/6/2008 • End-cap of EMC and TOF was ready on 2/12/2008 • Cosmic ray with full detector seen on 2/14/2008 • Cosmic ray data taking finished on 3/16/2008 • Moved to the BEPCII IR by mid-April, 2008 • Data taking is expected around mid-June, 2008.

  4. System overview

  5. 00 to 15 :::::: EMC 00 : NCluster >= 1 01 : NCluster >= 2 02 : Barrel Cluster back to back 03 : Endcap Cluster back to back 04 : Cluster Balance in Z direction 05 : Barrel Cluster Balance in Phi direction 06 : Endcap Cluster phi Balance 07 : Barrel total Energy Higher threshold 08 : Endcap total Energy Higher threshold 09 : total Energy Lower threshold 10 : total Energy Middle threshold 11 : Energy Balance in "Z" direction 12 : Barrel Energy difference Balance 13 : Endcap Energy difference Balance 14 : Energy Block Balance 15 : Endcap Energy Balance 16 to 21 :::::: TOF 16 : Endcap TOF back to back 17 : Barrel TOF back to back 18 : NETOF >= 2 19 : NETOF >= 1 20 : NBTOF >= 2 21 : NBTOF >= 1 (0x15) 32 to 37 :::::: MUON 32 : MUON Back to Back 3478 33 : MUON Back to Back 37 38 to 47 :::::: MDC 38 : Short Track back to back 39 : NStrk >= N 40 : NStrk >= 2 41 : NStrk >= 1 42 : Long Track back to back 43 : NLtrk >= N 44 : NLtrk >= 2 45 : NLtrk >= 1 46 : NItrk >= 1 47 : NItrk >= 2 触发条件和定时

  6. 触发道 • 0x1 => EMC Ncluster >= 1 • 0x2 => NBTOF >= 1 • 0x4 => BTOF back to back • 0x8 => EMC Cluster back to back • 0x10 => Short Track Back to Back • 0x20 => Long Track Back to Back && BTOF Back to Back • 0x100 => BTOF back to back && Ncluster >= 1 • 0x200 => random trigger • 0x400 => Long Track Back to Back && NCluster >= 1 • 0x800 => NLtrk >= 1 • 0x1000 => MUON Back to Back 3478 • 0x2000 => MUON Back to Back 37 • 0x4000 => NBTOF >= 1 && NClus >= 1 • 0x8000 => NLtrk >= N

  7. Run2414: 2008-03-06 18:17 to 03-07 09:00 Trigger channels: 0x441c Endcap Cluster phi Balance Long Track Back to Back && NCluster >= 1 ETOF back to back EMC Cluster back to back BTOF back to back Timing: 0x8022a11 Barrel TOF back to back Long Track back to back Barrel Cluster back to back

  8. 时间低阈的选取 随机触发，设置时间道高低阈相等，在不同时间阈值下测量漂移室各通道的时间计数，计数值阈触发数之比反映了漂移室在该时间阈下的噪声计数水平 • 在3#厅进行的宇宙线测试中，按噪声水平1%为标准，设置的时间低阈为 • 内室 110； 台阶 70； 大端板 50 • 内室 120； 台阶 80； 大端板 60 (数据分析得到的理想低阈) • 当前条件下，如果按1%的标准，时间低阈应为 • 内室 100； 台阶 70； 大端板 40

  9. Hitmap and distribution of T and Q (run1963) T hitmap Q hitmap T distribution Q distribution

  10. Results of calibration and reconstruction Distribution of drift time (layer 12) Time-to-distance relation (layer 12) Entries Drift time (ns) Drift time (ns) Drift distance (mm)

  11. Spatial resolution(after calibration and alignment) • HV: 2150V • T threshold: • 120/150(inner section), 80/110(stepped section), 60/80(outer section)

  12. Spatial resolution vs layer

  13. Efficiency vs layer

  14. TOF Calibration Using Cosmic Ray Data

  15. Time Difference of Each Counter The distribution of sum time of two end. The fitting function is Error Function. Mean value vs counter number Sigma value vs counter number

  16. T0 Extract σ=283ps Original T0 T0 Difference before and after T0 extract T0 after calibration σ=317ps σ=164ps Delta T distribution before and after T0 extract

  17. Single End Readout Time Resolution (Preliminary!) Using time difference of each counter and T0 extraction, with an approximation of β＝0.99, the single end readout time resolution are shown. East and West end readout time resolution with unit/ps

  18. How to calibrate by using cosmic rawdata • event Selection • EMCb2b • Energy of digi>10MeV, and only two digis • Check ADC(MeV) distribution for each crystal • First calibrated by using relative light yield data, • and comparison with the MCdata • Finally give the Preliminarycalibration constant for every crystal

  19. Hitmap of sample events

  20. 宇宙线事例：EMC b2b 触发 选择只击中两块晶体的事例

  21. ADC (MeV) vs nphi No calibration PMT RLY calibration Barrel light yield by PMT

  22. Preliminary results only using relative light yield data Barrel_all Gaus_landau fitting No-calib Sig/mean= 32.57/239.7=13.6% Cosmic RLY calib Sig/mean= 29.59/265=11.2% PMT RLY calib Sig/mean= 26.95/265.8=10.1% Fiber RLY calib Sig/mean= 29.01/262.3=11.1%

  23. First calibration by Cosmic rawdata MCData RawData Phi=29&30 Mean/RMS= 187.6/19.55 adc2-28l-2930 Mean=267MeV C1=Mean_mc/Mean_raw~188/267=0.7

  24. Preliminary results using relative light yield data & MC_calib Cosmic_mc Cosmic_rawdata , barrel_all Barrel_all Sig/mean= 12.34/184.4 =6.7% Only relative light yield by PMT test Sig/Mean=27/265.9 =10.1% The22&phi29 Sig/mean= 11.38/182.1 =6.25% relative light yield by PMT test +mc_calib Sig/Mean=16.7/183.4 =9.1%

  25. Preliminary results Sigma/mean by Gaus+landau fit

  26. Hit map By layer By segment Hit maps show pretty well, noise and dead channel have been checked and repaired

  27. Counting rate Trigger rate: 75~90Hz, Counting rate of MUC at 10-4 Hz/cm2 level

  28. 总结 • BESIII宇宙线调试总的来说进展顺利 • 已获取一定数量的宇宙线事例供离线进行软件调试和探测器性能的初步研究，帮助查找硬件中存在的问题 • 下月初进行第二轮宇宙线测试 • 准备迎接对撞取数

  29. 谢谢

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