Oct 18, 2018 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

Action Items

  1. BCAL and FCAL: Develop standard fiducial volume cuts for the calorimeters. Will be completed as part of the goals for efficiency measurements.
  2. FCAL: Cross check MC changes by Richard to make sure that gains are not affected in both Geant3 and Geant4 (Matt/IHEP)
  3. 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. (Matt)

MC check not to be forgotten

  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.

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%.


  1. FCAL HDFCAL log book
  2. BCAL HDBCAL log book

Tentative Agenda

  1. Announcements
  2. Action Items
  3. Goals for Calorimetry Group
  4. Run Updates
    1. FCAL
    2. BCAL
  5. Calibrations
  6. Reconstruction and Simulation
  7. NIM articles
  8. Any other business


Attending: Elton, Tolga, Colin, Beijiang Liu, Colin, Mark, Liping (JLab); Sean (FSU); Christina, George (Athens); Jon, Matt (IU); Tegan, Zisis, Karthik Suresh (UofR)

  1. Announcements
    • We welcome Karthik Suresh, new student at Regina, and Beijiang Liu from the Institute of High Energy Physics, China.
  2. Action Items
    1. To be completed along with the efficiency goals for calorimetry working group.
    2. Sean: MC generated with Richard's changes. Sean checked that the pi0 mass was ok in Geant3, but shifted down by up to 10% for Geant4. Richard will investigate with the photon particle gun.
    3. Matt: Need a monitoring plot to easily evaluate status of pedestals. Current plots seem to have a normalization that is not understood. Tolga volunteered to take a stab at this problem.
  3. Goals for Calorimetry Group
    • Working Group Discussion
    • The proposed goals were discussed briefly, with a consensus that they were important and timely.
  4. Run Updates
    1. FCAL
      • A smaller group will meet with Paul Smith and Fernando Barbosa on Monday to discuss possible changes to hardware to improve reliability.
    2. BCAL
  5. Calibrations
    1. BCAL MC nonlinear shower energy correction (Tegan)
      • Checking the non-linearity of BCAL showers in MC.
      • Currently not using SiPM saturation code.
      • Finds non-linearity correction ~1% above 0.5 GeV. Below 1 GeV larger corrections reaching 6% at 0.1 GeV.
      • Corrections will be added to CCDB.
      • Next step is to repeat exercise including the SiPM saturation into simulation and reconstruction.
  6. Reconstruction and Simulation
    1. Efficiency Updates (Jon)
      • Review of efficiencies computed for FCAL data and MC using the gp->pi+pi-pi0 with pi0->g(g) reaction.
      • Elton: Suggest making some scatter plots of missing E vs missing theta
      • Sean: Notes that hit times in FDC are not simulated correctly and may be impacting some of these results.
      • Sean: On summary plots of efficiency: too much info on the plot. Suggests to compute rations data/MC, so boxes with goals are unnecessary.
      • Discrepancies between data and MC for FCAL at small angles. This could be due to plexiglass shield (not yet included into MC) or more likely gain calibration around the beam hole that is not yet worked out.
      • Jon also investigated the BCAL with the same procedure.
      • First look shows that fits and comparisons between various methods and data/MC look reasonable. Preliminary results show efficiencies dropping to 50% at large angles with no energy cut.
    2. nan in bcal showers (From Beni)
      • No one has had time to take a look at this since this morning.
      • Mark: The BCAL determination of position is linear in the time difference and it would be difficult to create such an effect. It is likely the result of tracking.
      • [Note added after talking to Beni] The nan are in the MC REST files from Hao, but not found in one (random) run in 2017 data. Further investigation is needed.
  7. NIM articles
  8. Any other business