Apr 30, 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. PrimEXD FCAL energy calibration (for data & simulation) [2]
    2. PrimEx gain BCAL PrimEx Update
  5. Monitoring
    1. FCAL offline (Susan): Summary of batch 2 [3]
    2. BCAL offline (Tolga): Summary of batches 2-4 [4]
  6. Reconstruction
  7. Efficiencies
  8. Simulations
  9. Any other business


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

  1. Announcements:
    • Tentatively, Zisis will give the Calorimetry talk at Collaboration meeting.
    • Congratulations to Colin who starts a job at Union College in September. He plans to stay active in GlueX.
  2. Action Items: Mike's cos(φ) distribution was based on 2016 data; Keigo has done data alignment studies.
  3. Run Updates
    1. FCAL: IU plans to hire another postdoc in Colin's place. Until then, Nick and Chris know the base replacement ritual. Sean asked that Colin prepare documents on the calibration; some exist on FCAL hardware.
    2. BCAL
  4. Calibrations
    1. PrimEXD FCAL energy calibration (Igal): A detailed FCAL calibration and energy correction (both for data and MC) update was given by Igal including an introduction and goals of this experiment: 1% precision on the calibration to achieve 2.3% on the eta->gg width. The analysis focuses on θ < 7 deg and of course without magnetic field. The gain calibration was done without energy dependence correction and on a per ring basis. Slide 4: skims and cuts shown; the peak is not the π0 (peaks are at 100 MeV; Ilya's method); all bad channels have gains set to 1. Slide 7: quality check: +/-2% is good enough for now. Slide 8: there is a downwards shift after run 61800; it should be noted the the π0 calibration gets the η correct! Slide 9: Energy dependence correction one with an empircal formula (5th order); there is a ring dependence. [This spawned a lengthy conversation by email afterwards; Matt explained the process.] Matt noted that Cherenkov-photon angular distribution is not built into the MC. On slide 9, top left plot, there is a diagonal line, which is possibly due to noise; this affects fits on slides 11 and 12. Summary from data: rings 2-21 fits look ok. Slide 23: MC energy dependence: done in an iteratvive manner (6 iterations). Conclusion: new gains extracted; energy dependence can be improved.
    2. PrimEx gain BCAL (Karthik): Inclusive π0 analysis. FCAL Trigger bit used: π0 in time with triggered event in FCAL. Slide 6: good convergence on π0 mass; outlier fits checked individually. Slide 8: modified versus original calibration: different background, possibly due to charged pions. Slide 10: modified calibration loosk worse. Sasha noted that purity on L3 looks good enough for our purposes. Igal suggested to try background subtraction. A short discussion ensued about timing: check DEventRFBunch, DBeamPhoton and look st Δt_reconttructed(FCAL-BCAL). Next steps: non-linear energy correction.
  5. Monitoring
    1. FCAL offline (Susan): Susan wondered about the FCAL hit total energy which looks different (3 cases shown). Sean commented that it might be due to the fact that we are only looking at a fraction of the run (beam off, LED events, cosmics may affect this).
    2. BCAL offline (Tolga): Overall things look good. Occupancy, efficiency and reconstrution plots were shown. Eton commented that the vertical bands in the recon1 plots should be tagged by code as LED events (check). Recon2 plots show some differences (π- and p candidates). The dip on BCAL recon matching (projected hit module) differs from the reference plots occasionally. Sean suggested to look closer at tracking and put these observations on the Wiki validation page.
    3. LED monitoring (Varun): due to time constraints this presentation has been postponed until our next CALWG meeting.
  6. Reconstruction: no updates.
  7. Efficiencies: no updates.
  8. Simulations: no updates.
  9. Any other business: none.