Mar 19, 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

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

  1. Complete Calorimeter work packages

Long term items

Tentative Agenda

  1. Announcements
  2. Action Items
  3. Run Updates
    1. FCAL
    2. BCAL
  4. Calibrations
  5. Monitoring
  6. Reconstruction
  7. Efficiencies
  8. Simulations
  9. NIM articles
  10. Any other business


Attending: Mark D., Elton, Jon, Tolga, Varun, Christina, Colin, Sean, Sasha, Karthik, Edmundo, Sean, Zisis, Churamani, Matt.

  1. Announcements
  2. First fully virtual meeting since Jlab is in MEDCON5.
    • Announcement at Production and Analysis meeting.
    • Complete calibrations by April 1? See 2020 Data Production
    • Monitoring Plan
      • Current Monitoring Page
      • Tolga is checking the histograms and procedures for monitoring.
      • Zisis: He would like to be added to the list of monitors. (At a later stage he might pass this on to a new Regina student).
    • PRIMEX work (Karthik)
      • Investigating vertex dependence of pi0 peak. Using geometrical center of target instead of tracking.
      • Checking the following data periods separately: a) He CDC off, b) He CDC on, c) Be CDC off. B=0 for all runs. Removing empty target runs.
      • Mark: For comparison, suggests to also process normal GlueX production run using the same procedure as can be used for PRIMEX, i.e. using target geometrical center.
  3. Action Items
  4. Run Updates
    1. FCAL
      • New PDU has been installed that replaces the two previous PDUs (one for the bases; the other for the an agates). However, the remote control for the PDU has not been tested in the field yet. Colin is waiting for a long access to check it out.
      • 1-2 FCAL bases are being replaced per week. About 30-40 bases can be repaired; Nick has taken some home for repair. He will bring them into the lab when ready,
      • FCAL scalers: Group of 16 channels in the FCAL have anomalous pedestals. These channels also have about 1/2 nominal gain. Matt: Could it be that the module was replaced and has the full range at 1 V instead of 2 V. That might explain these anomalies. The module settings should be checked at the next access.
    2. BCAL
      • Log Entry 3806039 BCAL FP#9 is not always present. We have seen this problem before. It appears that the VME pulsing hardware is failing.
      • Sasha: Would like to separate out the FP triggers from the trigger plots and place into FCAL/BCAL sections. Zisis volunteered to do this.
      • There is a new hot channel in the BCAL. Serguei will adjust the pedestal for that channel by hand.
  5. Calibrations
    • FCAL Update (Colin)
    • Sixteen iterations so far showing that pi0 mass and width are converging.
    • The inner and outer 3 layers are excluded. No attempt to calibrate outer 3 layers, where the BCAL shadows the FCAL and no clear pi0 peak is visible.
    • There is about a 1% shift in mass over the course of the first data batch. The pi0 mass is low below run ~71500. Sean: The high intensity (350 nA) data started at 71600, so there may be a rate dependence. Matt: Should investigate the time dependence. Mark: Possibly use one set of gains and adjust (global) non-linear correction to the three different beam current periods.
    • Sasha asked about the capability of the base to handle higher rates. Matt: The increased anode current should be compensated by the active Cockcroft-Walton design.
    • Non-linearity correction: Use a DeltaE=500 MeV for selecting "symmetric" showers to see if the correction can be extended to higher energy. Deviations of the pi0 peak begin between 4 and 5 GeV, likely due to systematics. Matt: Problem may be merging clusters. Elton: The large DeltaE selection may also be contributing to the deviations. Colin: Reducing the DeltaE cut back to 100 MeV does not reduce the maximum systematic deviation very much and is consist with the wider cut. Will probably use the narrow cut for the calibration.
    • Timing: using Drew's algorithm developed for PRIMEX.
    • Most of the 4 ns shifts have been taken out for the FADCS in other detectors by comparing FADCs to TDCs, which is not possible for the FCAL.
    • So far, with limited statistics, the method seems to be working. More statistics is being added.
  6. Monitoring
  7. Reconstruction
  8. Efficiencies
  9. Simulations
    • Sean: Discrepancy between GEANT3 and GEANT4 scales, seen by Mark about a year ago and confirmed by Igal, was adjusted recently by Richard. It seems to bring the MC for GEANT3 and GEANT4 into reasonable agreement. Mark: the scale for single showers in the MC has been checked, but there still may be deviations for the pi0 peak.
  10. NIM articles
  11. Any other business