Dec 9, 2020 Calorimeter

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Meeting Day: WEDNESDAY
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 CALWG Items
  2. Long term items
  3. Calorimeter work packages

Tentative Agenda

  1. Announcements
  2. Run Preparations
    1. FCAL
    2. BCAL
    3. PrimEx/CCAL/FCAL-II
  3. Calibration
    1. FCAL Summer 2020 Gains (Colin)
    2. BCAL Gain Calibration Summer 2020 (Karthik)
      1. Gain calibrations for all the 4 batches (9-12) are done Summary.
      2. Slightly modified the runs in each batch to match the gains. Run by Run Mean
      3. Currently working to apply nonlinear energy corrections. applying corrections to the entire run period unlike for gain calibration where gains are computed for every batch.
  4. Monitoring
    1. BCAL LED
    2. BCAL (offline)
    3. FCAL (offline)
  5. Efficiency
  6. Reconstruction
  7. Simulations
  8. Action Items
  9. Any other business


Attending: Elton, Karthik, Zisis, Colin, Varun, Rebecca, Jon, Churamani, Sean, Malte, Tolga, Matt

  1. Announcements: Rebecca passed her candidacy exam. Congrats!
  2. Run Preparations
    1. FCAL: Matt reported that 91 bases (out of the first 100 pulled out) have been repaired and are holding voltage. Current is around 7 mA (15 mA is upper limit), but the 7mA was under high values of voltage. Ben Raydo installed a watchdog that checks when CPU hangs and reboots it which then re-enables the voltage. This was tested on one bases and seems to work. The cause of failures is still not understood, but with the refurbished bases and the watchdog we hope for improved stability for the 2021 PrimEx run. Next: another 100 bases will be pulled out and a mass firmware update will take place and a look at power consumption to test fuse limits.
    2. BCAL: it is dormant.
    3. PrimEx/CCAL/FCAL-II: no report.
  3. Calibration
    1. Colin showed the FCAL gain calibration from batch 9 (Summer 2020). After 3 iterations the mass of the pi0 stabilized at the correct mass. The width needs 8-9 iterations before it flattens out at 8 GeV. Colin will now set the gains for batch 9 and used them for batches 10-12. Past experience shows that those should converge after a couple iterations. Colin also showed the non-linearity curve. After a couple of more iterations the "pimples" below 4 GeV should disappear. Above 4 GeV, we will likely need Igal's method (calibrate by ring) and fix one photon to 1 GeV and scan the other, instead of using symmetric photons. The mass fits in the central region look quite good including those on the inner ring despite high background there.
    2. BCAL Gain Calibration Summer 2020 (Karthik)
      1. Gain calibrations for all the 4 batches (9-12) are done. Outliers at 40 nA beam current are from the CPP test runs. Sean advised checking the status entry in the CCDB tables; status=1 are production runs (CPP are status=0). These should help filter out those runs. Karthik recalibrated the last bunch of runs from bat 11, using bat 12 values and grouped them with those runs. There are gaps in the run number scan due to a Tape Silo issue in finding and copying those runs to cache.
      2. Currently working to apply nonlinear energy corrections to the entire run period unlike for gain calibration where gains are computed for every batch.
  4. Monitoring
    1. BCAL LED: no report
    2. BCAL (offline): no report
    3. FCAL (offline): no report
  5. Efficiency: Elton reported on the Task Force meeting last Friday in connection to studying photon reconstruction and efficiency. A lot of work was done by Churamani and Tolga. Feasibility of using the eta-prime is being examined. Susan has the status of the FCAL blocks done and Mark is checking these on the reconstruction and omega analysis. Rebecca is waiting to revisit the FCAL efficiency calculation. Elton mentioned Matt's proposal to use the b1 (larger xsection) but has the complication of two pi0s in the final state.
  6. Reconstruction: no report
  7. Simulations: Zisis reported on the G3vsG4 simulation work that Tegan is undertaking. Colin sent him the location of his files from the 2019/2020 studies, which are documented on GitHub (Issue 111).
  8. Action Items:
    1. Short term: Item #2: Task Force is looking at this. Matt agreed that it needs to be stufied.
  9. Any other business: Next CALWG Meeting will be on January 6, 2021. Have a good holiday break everyone.