Aug 6, 2020 Calorimeter

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Meeting Time: 11:00 a.m. JLab time

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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. Short term
    1. Richard Jones' work on G3vG4: run photon, pi+, pi-, proton particle guns. Who?
    2. Efficiency study: model mass and t-distributions
    3. Hadronic split off studies
    4. Covariance matrices for photons; should be redone.
    5. BCAL Wiki reorganization -> All
  2. Long term items

Tentative Agenda

  1. Announcements
  2. Action Items
  3. Run Update
    1. FCAL
    2. BCAL
  4. Calibrations
    1. Gain calibrations for all 8 batches Gain_Update (Karthik)
  5. Monitoring
    1. BCAL LED
      1. SiPM dark rate study update[2] (Varun)
    2. BCAL (offline)
      1. Discussion of V16 batch 1-6 (Tolga)[3]
    3. FCAL (offline) statusIV
  6. Reconstruction
  7. Efficiency
    • BCAL Hadronic Efficiencies (Elton) Summary: i) Kinematics between data and MC is reasonable, but not perfect. For BCAL and FCALBCAL, Data/MC differ by up to 8-10% at the lowest energy. ii) The discrepancy between Data/MC has increased since the analysis for the NIM paper.
  8. Simulations
  9. Any other business


Attending: Elton, Varun, Zisis, Tolga, Karthik, Christina, Mark, Churamani, Rebecca, Jon, Beni, Igal, Susan

  1. Announcements
    1. the experiment is running.
  2. Action Items
    1. Short Term
      1. Particle gun work will be undertaken by Regina
      2. See report below
      3. This is a long-term item of interest both to GlueX and JEF.
      4. Zisis continued Elton's work in cleaning up and reorganizing the BCAL Wiki.
    2. Long term:
      1. FCAL board was checked: it was at 1V and changed to 2V. Item resolved.
      2. Pending
  3. Run Update
    1. FCAL: Mark reported that around 8 bases have been replaced, one of which did not come up and will be checked. Another 9 need to bre replaced. Bases are in different states.
    2. BCAL: nominal, no issues.
  4. Calibrations
    1. Gain calibrations for all 8 batches: Karthik reported that the standard 8 batches were recalibrated (previously they all used Batch 2 ccdb values), but this time grouped into 4 batches based on similar gain behaviour. A few junk runs were removed from Batch 7 as well as the intensity scan runs. sigma/mu was shown and is fairly constant. The pi0 mass comes out to 0.1353 GeV/c2. Discrepancies in the slopes of the fitted mass within batches are less than 0.2%. We are good, and additional iterations are not needed. Karthik will communicate with Sean and then entere the new constants in ccdb.
  5. Monitoring
    1. BCAL LED:
      1. SiPM dark rate study update: Varun presented work by Jon and himself. They looked at pedestal RMS. The test pulsed Quadrant 3: 1000 triggers, at 18, 10 and 5 deg C, and V_ob=off, 0, ... to 2.0 V in steps of 0.2 V. The "off" values are plotted at V_ob=-0.2 V. Slide 4 has structures. Mark explained those based on the FADC behaviour; it produces integer values and noise results in a slow drift. He will adjust his script and provide it to Varun. Their was discussion about whether "off" values are equivalent to "off" contribution when V_ob=0 V. Mark suggested that channels should be looked at individually, rather than summing them in layers, as their noise behaviour is different, related possibly to position on the board and temp there. Channels with a larger offset are less sensitive to noise. Elton remarked that the noise contributes to the BCAL's resolution and Mark added that we might be up against limits in our technique in disentangling these.
      2. Varun looked at M23L2S2: it seems to have recovered! Mark commented on other things in the past mysteriously recovering (e.g. UP/DN ratio -- see appropriate log entries). Also; the upstream (bit 10 - upstream) was not firing; Mark will pulse just the upstream one. Varun will update the plot to include the UP/DN labels next to the bit numbers.
    2. BCAL (offline): Discussion of V16 batch 1-6: Tolga updated the BCAL monitoring, looking at occupancy, efficiency, reconstruction and matching histos. A hot channels is still present and shown on slide 3. Efficiency looks good. Recon1 neutral shower vs DT looks worse compared to previous Batch 1. There is a horizontal band between -2 and 2; Mark has seen this before, and now it is not as pronounced. Recon2 is pretty good. Susan wondered whether the similar bands seen in BCAL and FCAL are seen in other detectors. Next: look at Batches 7 and 8.
    3. FCAL (offline): Susan reported on FCAL monitoring, ver 15/16, Batches 1-6. A summary is given in the Table on slide 5. Some of the same issues are persisting, eg. upper left quadrant of occupancy plots. She looked at whether this issue developed over time, within a run. She used the FCAL online plugin and looked at subfiles for run 72104, namely _000 and _300. Nothing appears in _000 but the effect is visible in _300. Does this effect manifest itself at a high level variable? Needs thinkning. Mark: should 72104 be classified as a bad run? We do not have a procedure for analyzing a part of a run, as the overhead might be too much (need to speak to Sean). Run 72105 looks fine. Next: look at runs 72125-72162 ver 16, and long-term look at pi0 peak influences by rates, look at bad channel FCAL map and communicate with PrimEx people to see how they treated things.
  6. Reconstruction: nothing to report.
  7. Efficiency
    • BCAL Hadronic Efficiencies: Elton updated the group on his work. Reminder: this is a relative method that uses gp->pi+pi-pi0 (omegas go in the FCAL). The 2017/MC line was flat a year ago, but now data drops faster than MC at low energies. FCAL/BCAL has structure (10% or less effect). MC has been improved but still needs work. A chisquared cut < 2.5 was used. Deltas are cut away in data as they are not contained in the MC. Next: check accidental subtraction, unused energy and proton cut/t-dependence cuts. Summary: Kinematics between data and MC is reasonable, but not perfect. For BCAL and FCALBCAL, Data/MC differ by up to 8-10% at the lowest energy. The discrepancy between Data/MC has increased since the analysis for the NIM paper.
  8. Simulations: nothing to report
  9. Any other business: none