Aug 8, 2019 Calorimeter

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Meeting Time: 11:00 a.m.

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Participant Direct Lines

  • JLab Phone in CC L207 is 757-269-7084 (usual room)
  • JLab Phone: in CC F326 is 757-269-6460
  • Phone in the Regina Video-conference Suite is 306-585-4204
  • Athens Phone: in Christina's office is 011-30-210-727-6947


  1. FCAL HDFCAL log book
  2. BCAL HDBCAL log book

Goals for Calorimetry Group

  1. Determine preliminary photon reconstruction efficiencies as a function of E, phi and theta in data and simulation with a point-to-point precision of at least 5%.
  2. Measure systematics of pi0/eta mass calibration as a function of detector position to a precision of at east 5 MeV.
  3. Demonstrate agreement of photon reconstruction efficiency and resolution between data and simulation as a function of E, phi and theta to within 5%.

Action Items

Short term items:

  1. Investigate uniqueness tracking for efficiency calculations in calorimeters (Jon)
  2. Complete Calorimeter work packages

Long term items:

  1. From Mike's work: -cos(phi) type dependence in the data and a phi dependence at the downstream end of the bcal. See Sep 21, 2017 Calorimeter Meeting.
  2. FCAL: It has been noticed that the pi0 mass shifts when the LED pulser runs at high rate. This is still not understood. See Log Entry 3595928 and references. Several runs have been taken in raw mode. These runs exhibit the shift in pi0 mass with LED running at 1 kHz. There is a need to analyze these to try to determine the cause:
    1. 50634 - FCAL Green LED: 1kHz, 29 V, Livetime is 9%, 1.7 M events
    2. 50635 - FCAL Violet LED: 1kHz, 22 V, Livetime is 9%, 1.4 M events
    3. 50636 - FCAL Blue LED: 1kHz, 15 V, Livetime is 9%, 1.5 M events

Tentative Agenda

  1. Announcements
  2. Action Items
  3. Run Updates
    1. FCAL
    2. BCAL
  4. Calibrations
    1. Measurement of saturation in BCAL SiPMs (Elton)
  5. Monitoring
  6. Efficiencies
  7. Simulations
  8. BCAL Deep Learning
  9. NIM articles
  10. Any other business


Attending: Elton, Mark (JLab); Tegan, Karthik (UofR); Will (CMU); Matt (IU); Sean (FSU).

  1. Announcements
    • Run schedule delayed till Nov 25.
  2. Action Items
    • z-dependence of BCAL calibration (Karthik): Based on a suggestion from Mark, a BGGEN sample was being generated, but needs substantial more events. Mark noted that perhaps the study could be conducted with collaboration samples already generated (i.e. using REST files). This will be pursued offline.
    • Use omega events to determine BCAL shower efficiencies (Karthik). Reproducing previous studies by Mark to verify procedure.
    • We discussed how pressing is the item 8 (Determining energy resolution functions for FCAL and match to MC) as no one is identified to work on it. Not a priority at this moment.
    • Mark separated the calorimeter work packages into "in process" and "complete for future" to focus on immediate needs.
  3. Run Updates
    1. FCAL
    2. BCAL
  4. Fiducial volume cuts (Sean)
    • Following Marks studies on FV cuts, Sean had implemented changes on a branch to implement them, but not merged them till last week.
    • These FV cuts are implemented into the analysis library at the time energy cuts are applied, before reconstruction and kinematic fitting.
    • For the area around the beam, showers are removed that fall in the window frame of 2 blocks
    • These changes are being checked using the routine reconstruction tests. A further question are how the cuts affect the default number of showers that we wish to write out to trees. [In studies looking at the effect of cuts on additional showers, Alex (rho) sees a strong effect and Colin (eta pi) sees a weak effect. Further studies are needed.]
  5. Calibrations
    1. Measurement of saturation in BCAL SiPMs (Elton)
      • The parameter k (conversion from ADC counts to pixels) was measured in the lab, obtaining a value of k=1.05 pixel/count. The calculated value based on the gains of the system is 0.48 pixel/count and the empirical value used for the GlueX data following pi0 calibration is 0.25 pixel/count. See presentation for details and discussion.
  6. Monitoring
  7. Efficiencies
  8. Simulations
  9. BCAL Deep Learning
  10. NIM articles
  11. Any other business