X. DongAug. 5th, 2010 RNC Group Meeting 1 Barrel Time-Of-Flight In Run10 Xin Dong Many thanks to the TOF group

Aug. 5th, 2010 RNC Group MeetingX. Dong 2 TOF Close-out Review Reviewed on Aug 10-11, 2009 at BNL. Report can be found here: Construction stage -> Operation stage

Aug. 5th, 2010 RNC Group MeetingX. Dong 3 Run 10 “Summary”  120 full barrel trays installed  119 trays were active in Run 10 (one out due to the HV cable issue) - only 1 dead channel out of ~23000  Start detector (upVPD or VPD) hasn’t changed since last year  VPD coincidence (and vertex selection)  widely used as the MB condition at high energy collisions  A much cleaner trigger in low energy collisions  TOF multiplicity trigger  Central trigger  UPC trigger  VPD/TOF operation in Run10 went very well.  Preliminary calibrations (based on fast offline) are done, and in db.

Aug. 5th, 2010 RNC Group MeetingX. Dong 4 η~ 0η~ 0.9 Z One Tray One Module φ local Y local Z “+” ―To TPC center Barrel TOF Geometry

Aug. 5th, 2010 RNC Group MeetingX. Dong 5 Tray Alignment Calibration Use the low luminosity data taken on day 074 Do local (x,y,z) alignment in one loop. Tray alignment calibration constants were uploaded soon during 62 GeV run. Reflected in the fast offline data. Open: from fit to all Solid: from fit to modules 1-6 only

Aug. 5th, 2010 RNC Group MeetingX. Dong 6 Conventional Timing Calibration 1.Calibration for the start detectors - VPDs 2.Calculate the start time 3.Calibration for the BTOF trays - Need TPC tracking but enhanced by   at high p limit

Aug. 5th, 2010 RNC Group MeetingX. Dong GeV and 62 GeV (prel.) calibration 62 GeV200 GeV 85ps 90ps Difference comes from the start side Bingchu Huang

Aug. 5th, 2010 RNC Group MeetingX. Dong 8 When Going Down Energy Solutions: 1)Non-Vpd-Start (BTOF self) calibration algorithm implemented 2)Introduce a truncation algorithm in calculating the start time from VPD to suppress the outliers from slow particles The conventional VPD-start calibration method has some issues: 1)The small VPD acceptance causes to start losing significant amount of events, even central events. 2) Outliers from slow particles increase dramatically, which will dilute the start time resolution significantly.

Aug. 5th, 2010 RNC Group MeetingX. Dong 9 “Good” events are identified via offline analysis by requiring a valid vertex within |Vz|<75 cm and |Vxy|<2 cm ~ a few % minbias triggered events are “good” events VPD trigger rate ~ 2*collision rates within |Vz|<75cm 1/3 of VPD trigger triggered events are “good” events ~2/3 of “good” minibias events are labeled as VPD triggers BBC Minimum bias trigger: efficient but with large background VPD trigger: much cleaner but inefficient (missing central/peripheral) VPD trigger used as our luminosity monitor Triggers at 7.7 and 11.5 GeV AuAu 7.7 GeV

Aug. 5th, 2010 RNC Group MeetingX. Dong GeV - Truncation Calib. in VPD VPD Timing not symmetric in low energy collisions - single particle hit in each channel - slow particles lead to larger timings T diff = T i - (j!=i) Use truncated mean in calculating the averaged timing. Remove hits with top 20% high timing - coming from slow particles

Aug. 5th, 2010 RNC Group MeetingX. Dong GeV Calibration Rafael, Bill Resolution = 86ps With improved start side

Aug. 5th, 2010 RNC Group MeetingX. Dong 12 Calibration w/o VPD Calibration completely w/o VPD 62 GeV test Very promising timing resolution! Resolution (ns) # of pions T - T exp (ns) TDIG board ID Resolution (ns) # of pions Ming Shao

Aug. 5th, 2010 RNC Group MeetingX. Dong 13 Startless Calibration Strategy Step 1: Obtain the calibration constants (at expert level), two ways: - with the standard VPD start calibration conventional, but require more statistics due to VPD inefficiency - with the new BTOF self calibration Step 2: Apply the calibration constants to data - Algorithm with the new BTOF self calibration (maximize efficiency)

Aug. 5th, 2010 RNC Group MeetingX. Dong 14 Tof - Tof exp (ns) Day GeV Applying with BTOF self calib. algorithm 7.7 fast offline data Calibration constants obtained in 39 GeV with VPD-start calibration procedure. - Demonstrates the tray stability across different collision systems.

Aug. 5th, 2010 RNC Group MeetingX. Dong 15

Aug. 5th, 2010 RNC Group MeetingX. Dong 16 Particle flight time from TOF Track length from TPC Depend on masses of particles  Can be fitted with Gaussians default time resolution is 110 ps (Run9), may change with p for proton PID method (I) Masayuki Wada This is the default method in production!

Aug. 5th, 2010 RNC Group MeetingX. Dong 17 Calculate m 2 from  get the probability of being a particle Currently not in MuDst, people can calculate it by themselves if needed.  momentum and position resolution are essentially determined by the TPC Dylan Thein Masayuki Wada 1-Sigma error bar PID method (II) - M 2

Aug. 5th, 2010 RNC Group MeetingX. Dong 18 In progress PID combining TOF and dE/dx Masayuki Wada Yuri Fisyak

Aug. 5th, 2010 RNC Group MeetingX. Dong 19 pp2pp Run9 Efficiency = (tracks with matchFlag>0) / (tracks that can be projected to TOF modules) Remarks on Efficiency & Acceptance Acceptance: eta at Vz=0 phi averaged acceptance ~0.87 due to tray gaps TOF Matching * Acceptance ~ 0.8 * 0.87 ~ 0.7 single track at plateau - Run9 only 86 trays (out of 120), thus total TOF acceptance * efficiency ~ 0.5

Aug. 5th, 2010 RNC Group MeetingX. Dong 20 Summary 1) Run10 TOF operation went quite well. 2) Preliminary calibrations have been done - Promising performance in various collision energies  High energy datasets (200, 62.4 GeV) - Wait for the final TPC calibration and complete the TOF calibration for production  Low energy production are using the fast offline calibration - Check the TOF calibration when doing your analysis 3) TOF PidTraits is available in the MuDst for physics analysis  now developing an integrated PID algorithm combining TOF+dE/dx+(…)

Aug. 5th, 2010 RNC Group MeetingX. Dong 21 Calibration Status Preliminary 200 GeV and 62 GeV calibration were done, and constants were in db. 39 GeV calibration were finished, constants will be uploaded to db soon. 7.7 GeV calibration is underway (in accumulating enough statistics) - based on fast offline (preliminary TPC calibration) Important infrastructure updates: 1) Low energy runs: to suppress the outliers from slow particles, introducing a truncation algorithm in calculating the start time from VPD. 2) Non-Vpd-Start (BTOF self) calibration algorithm is implemented in the calibration maker to allow the BTOF self calibration. Fast offline QA - Ulisses Gulart, Rafael Derradi Vpd-start calibration - Rafael Derradi, Bingchu Huang, Bill Llope Non-vpd-start calibration - Ming Shao, Bill Llope

Aug. 5th, 2010 RNC Group MeetingX. Dong 22 Applying with BTOF self calib. algorithm 62 GeV: Constants from the Vpd-Start calibration in data base (alignment not updated when these constants were obtained) 62 GeV

Aug. 5th, 2010 RNC Group MeetingX. Dong 23 How to load TOF calibration … gSystem->Load("StBTofUtil"); gSystem->Load("StVpdCalibMaker"); gSystem->Load("StBTofCalibMaker"); StChain *chain = new StChain("StChain"); StMuDstMaker *muDstMaker = new StMuDstMaker(0,0,"",fileList,"MuDst.root",nfiles); St_db_Maker *dbMk = new St_db_Maker("db","MySQL:StarDb","$STAR/StarDb","StarDb"); StVpdCalibMaker *vpdCalib = new StVpdCalibMaker(); vpdCalib->setMuDstIn(); StBTofCalibMaker *btofCalib = new StBTofCalibMaker(); btofCalib->setMuDstIn(); StMyMaker *myMaker = new StMyMaker(); …

Aug. 5th, 2010 RNC Group MeetingX. Dong 24 Introduce xLocal Bingchu Huang