May 28, 2020 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
  3. Calibrations: 2020 Data Production; RunPeriod-2019-11 Validation; Offline Monitoring Data Validation

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 least 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

  1. Check switches on FCAL board with high scaler rates and make sure it is set to 2 V full scale. (Colin and Sasha)
  2. Long term items

Tentative Agenda

  1. Announcements:
  2. Action Items
  3. Run Updates
    1. FCAL
    2. BCAL
  4. Calibrations
    1. FCAL (Igal - PrimEx): [2]
    2. BCAL (Karthik - PrimEx): Nonlinearity Update
  5. Monitoring
    1. BCAL LED (Varun): Monitoring Update [3]
    2. BCAL (offline)
    3. FCAL (offline)
  6. Reconstruction
  7. Efficiencies
    1. Photon efficiencies for different run periods
  8. Simulations
    1. Comparing simulation and data (Colin)
  9. Any other business


Attending: Igal, Mark, Varun, Zisis, Tolga, Jon, Elton, Christina, Colin, Sasha, Churamani, Karthik, Sean, Matt, Susan

  1. Announcements:
    1. Director's newsletter and MEDCON5 plans:
    2. Run: 6 hour shifts with local people: Lab staff plus others in the viscinity, following a 15 day quarantine if they have travelled.
  2. Action Items
    1. Keigo presented at the Collaboration meeting. Things have been very stable since Mike S. did his study. This action item is considered closed.
    2. Sasha will undertake trainiing from Colin for FCAL bases. There is a Wiki page and Colin is updating documentation by Adesh and Jon. This is a short-term solution. A senior person should be tasked with FCAL oversight. This should be brought up with Eugene.
  3. Run Updates
    1. FCAL
      • Inner base status Inner base map to show ones in good condition/repaired, ones needing attention and some not found in JInventory. This work will happen in the fall. Sasha mentioned the need for better alignment.
    2. BCAL
      • Log Entry 3810885 (Nick Sandoval) Chiller alarms where a communications issue that is being resolved. At our next CALWG meeting we will go how to turn things back on when the time comes.
  4. Calibrations
    1. FCAL (Igal - PrimEx): [4] Gain matching with focus on outer rings. Clear pi0 peak (Ilya's method) w/o tracking. Matt: look at plots with old calibration constants to verify the size of the effect. Recalibration is done every 8 days, moving to 4 days. Eta peak position changes w.r.t. pi0 peak possibly due to threshold. Matt: change 5 MeV threshold in HG4 and recompile to study this. Bug in FCAL factory went undetected because it is small, but still worth looking at this. Matt: no good mechanism was found to study these effects in data at low energy.
    2. BCAL (Karthik - PrimEx): Nonlinearity Update Monitoring plots show an increase in the pi0 mass value at higher energies. Ask Alex A about vertex in these skims. Igal: iwas this studied versus polar angle? Karthik: no. Mass ratio shown for symmetric photons (adequate stats up to 2.5 GeV). Emax/Emin method probes higher energies. Primary source of nonlinearity after SiPM saturation correction is leakage; this can be modelled. Nonlin method may over-correct at higher energies for PrimEx. Elton summarized the non-linear function and process based on the J/psi results from ~2 years ago. MC is better now, more stats, perhaps we should revisit this. Mark: we should be suspicious as electron radiation not taken into effect. Sean cautioned using the monitoring plots and fits (3rd order pol for background). These are a red heering and the monitoring plots should be fixed so as not to mislead people. Next meeting: Mark will report on his simulation studies and energy correction.
  5. Monitoring
    1. BCAL LED (Varun): Monitoring Update [5] Slide 3: each point is a fit of the time variation. The plot shows an azimuthal variation. Checks: i) make sure that jump in 150-250 nA is not due to tuning runs. ii) check continuity from module 48 back to module 1. Mark: effect is ~2%, but we are looking at 1% on the non-linearity; if we divide into batches we will have ~0.5% effect per batch. Mark will look more carefully at the up/dn ratios. Sean: take a constant set of gains (from pi0) and compare batch 2 to 8 (all 350 nA runs).
    2. BCAL (offline): new batch/plots available soon.
    3. FCAL (offline): new batch/plots available soon.
  6. Reconstruction: nothing
  7. Efficiencies
    1. Photon efficiencies for different run periods: Sean: apply studies to 2018 data sets. Matt/Jon are redoing Jon's FCAL efficiency study. Elton will pass his costheta_cm code to someone else (maybe contact IHEP again).
  8. Simulations
    1. Comparing simulation and data (Colin) Deferred to next meeting.
  9. Any other business