Feb 7, 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. Fix FCAL online monitoring plugin to properly plot low level digi quantities in 2D displays. 2D display of pedestal is hard to get because occupancy plot is filled in a different loop. (Tolga)
  3. BCAL: Check pulsing rate of LED triggers when FP trigger bit is missing (start with early runs in fall 2018). With discerning software, check pulsing rate of later runs where it appeared that the downstream FP LED bit was not firing. (Ahmed)
  4. BCAL: Check that latest gain ratios are uploaded for spring 2018 (Mark). Sean has checked this.

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.

Tentative Agenda

  1. Announcements
  2. Action Items
    1. Review of Goals for the Calorimetry Group (see section above)
    2. Complete list of Calorimeter Work Packages
  3. Run Updates
    1. FCAL
    2. BCAL
  4. Calibrations
  5. Reconstruction and Simulation
    1. Costhe Efficiency Method (Elton)
    2. Jon's Efficiency Updates: Photon Gun Studies
  6. Monitoring
  7. NIM articles
  8. Any other business


Attending: Elton, Mark, Colin, Shankar, Sean (JLab); Curtis, Will (CMU); Christina, George (Athens); Jon, Matt (IU); Zisis, Ahmed, Karthik (Regina); Tolga, Rupesh (FSU).

  1. Announcements
    • Beam is expected for the weekend
    • Collaboration meeting: Matt has volunteered to summarize FCAL and BCAL into a single talk. 30 min have been allocated. He has requested the slides for the presentation to be sent to him by next Thu (Feb 14).
  2. Action Items
    1. Fix FCAL online monitoring plugin to properly plot low level digi quantities. Tolga: Script in progress, busy few weeks so far. Unlikely to have edited in test plot to show in time.## Review of Goals for the Calorimetry Group (see section above)
      • Tolga: leaned process for fast submission for his analysis and plans to use the same scheme to develop the plugin.
      • Mark Dalton: Noted that internally 2D histograms are stored as 1D and root has tools that allows access to the 1D indexing scheme. Tolga can call Mark for more details.
    2. BCAL: Checking rate of events with missing FP triggers in fall 2018 run. Ahmed has produced plots but has not evaluated the data.
  3. Run Updates
    1. FCAL
      • Colin: Sasha replaced a problematic FADC board. There are a few dead channels that will be fixed next week.
    2. BCAL: Ready for spring run.
  4. Calibrations
    1. BCAL gains (Karthik)
      • Completed calibrations for fall and results are starting to converge.
      • Taken some runs with pixel/count = 0.1, 0.2, 0.4 and 0.478 (calculated). Does not see much of a change in the non-linearity correction even though there were clear variations seen in the spring analysis. Will compile results and circulate for comments.
      • Resolutions are roughly unchanged between spring and fall. A couple of channels seem to be off at the 5% level. Will check that fits are good and circulate list so that Mark/Elton can check whether they correspond to a list of previously seen problems.
      • Mark and Sean: Check response of fall data using the spring constants (before iterating) to evaluate changes.
      • Elton: See if the pixel/count=0.478 values can be used effectively with the fall data set now that new high level calibrations (from Mark) have been updated.
  5. Reconstruction and Simulation
    1. Costhe Efficiency Method (Elton)
      • GlueX-doc-3875 Status slides
        • Elton presented a summary of the costhe* efficiency method, summary of work by IHEP and status of his work. Note a final slide has been added to the GlueX doc that was not available a the time of the meeting.
        • The samples of pi0s used come from the reaction gp->pi+pi-pi0, pi0->gg.
        • Matt: This method does not determine an absolute efficiency, but may be useful in concert with other methods to bridge gaps, for example between BCAL and FCAL.
        • Elton: This method could possibly be used with inclusive pi0s but background may be problematic. Matt: Side band subtraction might prove valuable.
      • GlueX-doc-3844 Preliminary Analysis by IHEP
      • GlueX-doc-3857 Toy MC
    2. Jon's Efficiency Updates: Photon Gun Studies
      • Jon has updated software that allows quick and consistent iteration to produce output plots.
      • Shows that the inclusion of charged tracks in the events with photons tend to reduced the reconstruction efficiency.
      • Christina: Does vetoing on charged tracks result in vetoing of photon conversions? Jon: Possibly, but they are likely difficult to reconstruct cleanly.
  6. Monitoring
  7. NIM articles
  8. Any other business
    • Collaboration meeting in two weeks. Next meeting will be Mar 7.