Dec 15, 2016 Calorimeter

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Video Conferencing Information

Meeting Time: 11:00 a.m.

  1. To join via a Web Browser, go to the page [1]
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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

Action Items

  • Produce documentation for implementation of timing algorithms and constants (Andrei) GlueX-doc-3165 draft posted


  1. FCAL HDFCAL log book
  2. BCAL HDBCAL log book
  3. BCAL Action Items and Working Tasks

Tentative Agenda

  1. Announcements
  2. Action Items
  3. Run preparations
  4. FCAL update
  5. BCAL update
    1. π0 Dalitz decay for detector studies - George, Christine
  6. Calibrations
  7. Reconstruction and Simulation
  8. NIM articles
  9. Any other business


Attendees: Elton, Jon, Mark (JLab); Zisis, Tegan (UofR); George, Christine (Athens); Curtis (CMU).

  1. Announcements
    • Accelerator started tuning beam to Hall D yesterday. A couple of hours of beam was received with radiation levels at or below those from the spring.
    • The solenoid tripped several times during ramping. Final ramping at half nominal rate reached 1200 A, where it has been stable since last evening. We will keep this current for most of the run.
    • The tagger magnet tripped last night and accelerator was in the process of repair. [It was fixed by the time of the meeting]
    • Tuning and other Hall D studies are underway
  2. Action Items
    • Completed for 2016!
  3. Run preparations
    1. Environment
    • Bcal biases on and stable at 5 deg C. Integration window reduced to 3-13 counts, so gains will have to be adjusted accordingly.
    • Fcal voltages on and stable. About 6 bases are problematic, but few new failures
  4. FCAL update (Jon)
      • Had a little scare last Friday when Jon tried to turn the voltages on and they were unresponsive
      • After some investigation, it was found that the hardware interlock on voltages required a valid humidity range with a minimum of 10%.
      • The Fcal darkroom humidity was about 8%, which was preventing turning the voltages on. See Log Entry 3445810. The humidity tracks the trends in the hall and outside. With the cold weather, the humidity has dipped below 10% a couple of times in the past month. The lowest value recorded has been 8%.
      • The lower limits was reduced to 5%, which allows operation. Fernando and Paul Smith do not see a problem with operation at this level of humidity, although they advise grounding while working on the electronics to guard against static discharge.
      • During the debugging process, we found that the EPICS alarms did not have a lower limit set for the humidity. Therefore there were not alarms and the software was not even indicating an alarm state even when the system was locked out by the interlock. Hovanes has updated the values in EPICS to correspond to the hardware and will now indicate the interlock status as well as show alarms with two thresholds.
    1. Base Repair
      • Chis is repairing about 10-15 bases per week
      • Once fixed, Jon updates the JInventory database, checks pulses on the scope in the dark box, places in the monitoring setup for longer term observation.
      • To date there have been three cases where bases with the 4-resistor replacement "fix" have failed. These are being sent to Paul Smith for testing and diagnostics. Further improvements to the "fixes" will need to be developed.
  5. BCAL update
    1. π0 Dalitz decay for detector studies - George, Christine
      • George started selection of the g p->pi0 p -> ge+e- p reaction to be used for detector studies.
      • Plots are shown that use replay version 3 for the Golden runs of spring 2016
      • Feedback was made on various plots
      • Mark: Suggestion to cut hard to select a clean sign that can be used to study features of the signal
      • Christina: 1) Consider using dE/dx from chambers to further identify electrons. Elton: pions will be difficult to distinguish from electrons in the chambers. 2) Use target information and vertex reconstruction. Mark/George: At the moment the kinematic fit requires a common vertex for ge+e-p in order to converge. Detached vertex reconstruction is not currently implemented in a routine way.
  6. Calibrations
  7. Reconstruction and Simulation
    • Mark: Working on reconstruction. Starting to calibrate the MC as with data to be able to optimize reconstruction of data. In particular obtain better parameterizations for neutral and charged showers.
  8. NIM articles
    • Zisis: Called a local meeting today to review input to the NIM article from Regina. George Lolos is contributing to this effort.
    • Use input from group to gather content and identify "NIM-worthy" issues.
    • Use these to firm up the table of contents, which should be available before the end of the year
  9. Any other business
    • Happy Holidays!
    • Next meeting will be Jan 12, 2017.