Aug 10, 2017 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]
  2. To join via Polycom room system go to the IP Address: ( and enter the meeting ID: 907185247.
  3. To join via phone, use one of the following numbers and the Conference ID: 907185247.
    • US or Canada: +1 408 740 7256 or
    • US or Canada: +1 888 240 2560
  4. Upon connection all microphones are automatically muted. To unmute your mike on a Polycom or equivalent unit, enter *4. Unmuting on a computer is trivial as there is a microphone button than can be clicked.
  5. More information on connecting to bluejeans is available.

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. Check in the code, including scripts, that is used for recent calibrations into git (BCAL: Mark, FCAL:Adesh)
  2. Add Fcal dead channels into the MC
  3. Find the geometry for the light tight cover to the FCAL (Elton)


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

Tentative Agenda

  1. Announcements
  2. Action Items
  3. Activities during the down
  4. FCAL Update
  5. BCAL update
    1. Pedestal width and mean study [2]
  6. Calibrations
  7. Reconstruction and Simulation
    1. 2017 mcsmear Workplan
  8. NIM articles
  9. Any other business


Attendees: Elton, Curtis, Mark (JLab); Will (CMU); Matt, Jon (IU); Zisis, Tegan, Ahmed, Andrei (UofR); Christina, George (Athens)

  1. Announcements
    • Accelerator startup postponed till after Thanksgiving.
  2. Action Items
    • Fcal black cover: Elton has checked e-mails, meeting notes, drawings. Cover was ABS plastic and mounted in about Nov 2013. No mention of thickness found. Send inquiry to Tom and Tim. Matt: Could check the PRs. JLab probably ordered it.
  3. Activities during the down
    • Work will also be delayed due to the accelerator schedule.
  4. FCAL Update
    • Little progress since last meeting due to changes in manpower
    • Two first-year students are starting in the group, but qualifying exams are next week
    • Colin Gleason, new post-doc will begin Sep 1. He previously worked in Hall B and will be based at JLab.
    • Some efforts reported already will not have a near-term impact. LED data will not be very useful for time studies due to variations in firing times. However the exclusive omega sample may prove very useful. At first glance it appears that important gains in time resolution can be made by using averages instead of a single time from the highest energy block.
    • Collaboration goal is to tune MC by mid Sep to start generating simulation samples. By then one should be able to include dead channels in to the MC, but probably not many other improvements.
  5. BCAL update
    1. Pedestal width and mean study [3]
      • Redo studies completed by Mark some time ago on pedestal widths vs over bias.
      • Studies completed at 18, 10 and 5 deg chiller settings. (Points below zero over bias are for data taken with SiPMs off)
      • New data is consistent with previous studies. At current operational conditions (T=5 deg, Vover=1.4V), the pedestal widths are about 5% larger than at 0V (depend on layer). The pedestal means vary by about 0.2% as the over bias increases.
  6. Calibrations
    • Tegan: Working on gain calibration using exclusive pi0 sample (Will used inclusive pi0s).
    • Finds that the pi0 mass is fluctuating between 128 to 140 MeV for different iterations. He is presently at iteration 7.
    • The pi0 width is about 9 MeV.
    • Will: Changes in value of the pi0 mass is not unusual; after final iteration, the gains may need to be scaled to the correct mass
  7. Tegan and Will to find a convenient time to review the procedures in detail.
  8. Reconstruction and Simulation
    1. 2017 mcsmear Workplan
    2. Eta widths (Mark)
      • Using the 2017 sample of pi+pi-eta selected with a kinematic fit (not including the eta mass).
      • Simulation uses genr8 at 9 GeV incident photons. Distributions are close to data. Plotting sigma_eta vs E BCAL shows good agreement between data and simulation. FCAL simulation is much narrower than the data.
      • MCsmear uses a c1/sqrt(E) + c2 parameterization (linear instead of quadrature addition). Will change it to be a quadratic sum and try to optimize parameters
      • Will: Checking that pi0 simulation still describes the data, which it did a year ago.
      • Finds that the new pi0 mass is low in simulation at about 131 MeV. Will need to scale up gains to match (for now in private sqlite file)
      • Non-linear corrections may need to be re-examined.
      • Mark: What has changed in the MC since last year? Will: Not clear what the cause, but z-pos parameters, attenuation length, etc, which may affect the mass in some way. Jobs currently running will show status.
  9. NIM articles
    • Draft performance slides for BCAL NIM
    • Elton showed preliminary versions of plots proposed for the performance section and collected feedback.
    • Zisis has updated some sections on the detailed MC.
  10. Any other business