TPC Calibrations

TPC Calibration & Data-Readiness Tasks:

Notes:
* "Run", with a capital 'R', refers to a year's Run period, e.g. Run 10)
* Not all people who have worked on various tasks are listed as they were recalled only from (faulty) memory and only primary persons are shown. Corrections and additions are welcome.

  1. You do not have access to view this node
    • Should be done each time the TPC may be moved (e.g. STAR is rolled out and back into the WAH) (not done in years)
    • Must be done before magnet endcaps are moved in
    • Past workers: J. Castillo (Runs 3,4), E. Hjort (Runs 5,6), Y. Fisyak (Run 14)
  2. TPC Pad Pedestals
    • Necessary for online cluster finding and zero suppression
    • Uses turned down anode HV
    • Performed by DAQ group frequently during Run
    • Past workers: A. Ljubicic
  3. TPC Pad Relative Gains & Relative T0s
    • Necessary for online cluster finding and zero suppression
    • Uses pulsers
    • Performed by DAQ group occasionally during Run
    • Past workers: A. Ljubicic
  4. TPC Dead RDOs
    • Influences track reconstruction
    • Monitored by DAQ
    • Past workers: A. Ljubicic
  5. You do not have access to view this node
    • Monitor continually during Run
    • Currently calibrated from laser runs and uploaded to the DB automatically
    • Past workers: J. Castillo (Runs 3,4), E. Hjort (Runs 5,6), A. Rose (Run 7), V. Dzhordzhadze (Run 8), S. Shi (Run 9), M. Naglis (Run 10), G. Van Buren (Run 12)
  6. TPC Anode HV
    • Trips should be recorded to avoid during reconstruction
    • Dead regions may influence track reconstruction
    • Reduced voltage will influence dE/dx
    • Dead/reduced voltage near inner/outer boundary will affect GridLeak
    • Past workers: G. Van Buren (Run 9)
  7. TPC Floating Gated Grid Wires
    • Wires no longer connected to voltage cause minor GridLeak-like distortions at one GG polarity
    • Currently known to be two wires in Sector 3 (seen in reversed polarity), and two wires in sector 8 (corrected with reversed polarity)
    • Past workers: G. Van Buren (Run 5)
  8. TPC T0s
    • Potentially: global, sector, padrow
    • Could be different for different triggers
    • Once per Run
    • Past workers: J. Castillo (Runs 3,4), Eric Hjort (Runs 5,6), G. Webb (Run 9), M. Naglis (Runs 10,11,12), Y. Fisyak (Run 14)
  9. You do not have access to view this node
    • Dependence of reconstructed time on pulse height seen only in Run 9 so far (un-shaped pulses)
    • Past workers: G. Van Buren (Run 9)
  10. You do not have access to view this node
    • Known shorts can be automatically monitored and uploaded to the DB during Run
    • New shorts need determination of location and magnitude, and may require low luminosity data
    • Past workers: G. Van Buren (Runs 4,5,6,7,8,9,10)
  11. You do not have access to view this node
    • Two parts: Inner/Outer Alignment, and Super-Sector Alignment
    • Requires low luminosity data
    • In recent years, done at least once per Run, and per magnetic field setting (perhaps not necessary)
    • Past workers: B. Choi (Run 1), H. Qiu (Run 7), G. Van Buren (Run 8), G. Webb (Run 9), L. Na (Run 10), Y. Fisyak (Run 14)
  12. TPC Clocking (Rotation of east half with respect to west)
    • Best done with low luminosity data
    • Calibration believed to be infrequently needed (not done in years)
    • Past workers: J. Castillo (Runs 3,4), Y. Fisyak (Run 14)
  13. TPC IFC Shift
    • Best done with low luminosity data
    • Calibration believed to be infrequently needed (not done in years)
    • Past workers: J. Dunlop (Runs 1,2 [here, here]), J. Castillo (Runs 3,4), Y. Fisyak (Run 14)
  14. Twist (ExB) Distortion
    • Best done with low luminosity data
    • At least once per Run, and per magnetic field setting
    • Past workers: J. Castillo (Runs 3,4), E. Hjort (Runs 5,6), A. Rose (Runs 7,8,9), Z. Ahammed (Run 10), R. Negrao (Run 11), M. Naglis (Run 12), J. Campbell (Runs 13,14), Y. Fisyak (Run 14)
  15. You do not have access to view this node
    • Done with low (no) luminosity data from known distortions
    • Done once (but could benefit from checking again)
    • Past workers: G. Van Buren (Run 4), M. Mustafa (Run 4 repeated)
  16. You do not have access to view this node
    • At least once per Run, and per beam energy & species, and per magnetic field setting
    • Past workers: J. Dunlop (Runs 1,2), G. Van Buren (Runs 4,5,6,7,8-dAu,12-pp500), H. Qiu (Run 8-pp), J. Seele (Run 9-pp500), G. Webb (Run 9-pp200), J. Zhao (Run 10), A. Davila (Runs 11,12-UU192,pp200,pp500), D. Garand (Run 12-CuAu200), M Vanderbroucke (Run 13), M. Posik (Run 12-UU192 with new alignment), P. Federic (Run 12-CuAu200 R&D)
  17. You do not have access to view this node
    • Once per Run, and per beam energy & species, and per magnetic field setting
    • Past workers: Y. Fisyak (Runs 1,2,3,4,5,6,7,9), P. Fachini (Run 8), L. Xue (Run 10), Y. Guo (Run 11), M. Skoby (Runs 9-pp200,12-pp200,pp500), R. Haque (Run 12-UU192,CuAu200)
  18. TPC Hit Errors
    • Once per Run, and per beam energy & species, and per magnetic field setting
    • Past workers: V. Perev (Runs 5,7,9), M. Naglis (Runs 9-pp200,10,11,12-UU193), R. Witt (Run 12-pp200,pp500, Run13)

To better understand what is the effect of distortions on momentum measurements in the TPC, the attached sagitta.pdf file shows the relationship between track sagitta and its transverse momentum.