Apr 18, 2019 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

Short term items:

  1. Complete Calorimeter work packages
  2. BCAL. Remove BCAL LED triggers from monitoring occupancy plots. (Sean) Completed
  3. FCAL. Collin to show Elton and Mark how to restore bases when communication is lost (Colin, Elton, Mark). Done.
  4. BCAL. Produced histograms of total event energy for a) physics triggers and b) LED FP triggers to decide on online monitoring selection (Ahmed) See details below

Long term items:

  1. From Mike's work: -cos(phi) type dependence in the data and a phi dependence at the downstream end of the bcal. See Sep 21, 2017 Calorimeter Meeting.
  2. FCAL: It has been noticed that the pi0 mass shifts when the LED pulser runs at high rate. This is still not understood. See Log Entry 3595928 and references. Several runs have been taken in raw mode. These runs exhibit the shift in pi0 mass with LED running at 1 kHz. There is a need to analyze these to try to determine the cause:
    1. 50634 - FCAL Green LED: 1kHz, 29 V, Livetime is 9%, 1.7 M events
    2. 50635 - FCAL Violet LED: 1kHz, 22 V, Livetime is 9%, 1.4 M events
    3. 50636 - FCAL Blue LED: 1kHz, 15 V, Livetime is 9%, 1.5 M events

Tentative Agenda

  1. Announcements
    1. Collaboration Meeting May 14-16, 2019 at Jefferson Lab.
  2. Action Items
  3. Run Updates
    1. FCAL
    2. BCAL
  4. Calibrations
    1. GlueX-doc-3976 Update Costhe Efficiency Method (Elton)
  5. Monitoring
  6. NIM articles
  7. Simulations
  8. Any other business


Attending: Elton, Colin, Mark, Sean (JLab); Tolga (FIU); George (Athens); Matt (IU); Tegan, Zisis, Karthik, Ahmed (UofR); Curtis, Will (CMU).

  1. Announcements
    1. Collaboration Meeting May 14-16, 2019 at Jefferson Lab.
      • Zisis will give the Calorimetry report at the collaboration meeting
      • Mark will give the report at the Data/MC comparison Workshop
  2. Action Items
    • We reviewed the calorimeter work packages.
      • Matt commented on the FCAL calculation by Jon: Plan is to (at least) have an update on status of the measurement by the collaboration meeting. The final loose end comes from a 90% measurement with the photon gun and 95% with w-decays, which is not understood.
      • Karthik (and Zisis) have been in communication with Jon to understand the omega decay process to determined efficiencies in the BCAL. Some initial jobs have been submitted to the OSG.
    • First two items completed. See monitoring item for information on the 3rd item.
  3. Run Updates.
    1. There will be a power outage on Monday, so everything should be shut down in an orderly fashion before then. FCAL and BCAL are both off now. Elton will coordinate with Fernando about shutting down electronics tomorrow.
    2. Work packages for summer
      • FCAL: Electronics lab is moving to EEL and Colin will make sure that all equipment is moved over.
      • BCAL: The occupancy plots looked ragged during the PRIMEX run. This could be due to triggering only on CCAL and FCAL and/or no magnetic field. During the down time we should check that cables are still secure and pedestals are stable in advance of the Nov run.
  4. Calibrations
    1. GlueX-doc-3976 Update Costhe Efficiency Method (Elton)
      • See also Log Entry 3679547 for more plots.
      • Elton gave an update on the method. One of the main systematics are differences between runs, which are not quite understood.
      • Plan is to run more MC at specific runs to compare with data and investigate systematics between different run settings and see how these track between data and MC.
      • The results of this investigation will be written up before the collaboration meeting.
    2. FCAL calibration update (Colin)
      • Fall 2018 near completion, but need to check failed runs.
      • Low luminosity runs will be complete later today.
      • Checks for changes in gains for spring. Timing offsets seem to be ok.
      • Sean: Suggests that the FCAL gains be determined in the same way as for previous periods, leaving Ilya's evaluation for checks.
    3. BCAL calibration update (Karthik)
      • Fall 2018 calibration complete
      • Working on understanding systematics vs z (position along calorimeter). Some fits to pi0 mass at intermediate photon energies had a strange behavior, but seem to be fixed by adjusting the fitting range to avoid bias due to low-energy background.
  5. Monitoring
    1. See Fig.5 in Report (Ahmed)
      • There was discussion spurred by plots in the document.
      • The energy cut of E>20 GeV is used to select LED events and distinguish them from physics events.
      • Mark: The online (ROOTSPY) processing of data cannot be depended on to evaluate the low rate of LED triggers. Concentrate on 24 hour feedback with monitoring plots.
      • Elton: Need a plot that can show at a glance whether the LED is firing. Mark: Occupancy plot for LED triggers can give additional information as to whether some parts are failing to fire.
      • Sean: For online monitors, one could consider firing the LEDs at high rate at the beginning of a run, which would be included into the first 3 files that are saved for evaluation.
  6. NIM articles
  7. Simulations
  8. Any other business