June 16, 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] https://bluejeans.com/907185247.
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Participant Direct Lines

  • JLab Phone: in CC F326 is 757-269-6460 (usual room)
  • JLab Phone in CC L207 is 757-269-7084
  • 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. FCAL HDFCAL log book
  2. BCAL HDBCAL log book
  3. BCAL Action Items and Working Tasks

Tentative Agenda

  1. Announcements
  2. Action Items
  3. Preparation for REST production
    1. Runs with bad BOR records
  4. FCAL update
    1. Efficiency Studies (Jon)
  5. BCAL update
    1. 2gamma systematics (Will)
  6. Calibrations
  7. Reconstruction and Simulation
  8. Any other business


Attendees:Elton, Mark, Simon, Adesh, Jon (JLab); Will (CMU); Christina, George (Athens); Andrei, Tegan, Ahmed (UofR); Matt (IU); Sean (NW)

  1. Announcements
    • Users Group Annual meeting next week. Nice agenda scheduled. See Meeting Page. YouTube streaming is available each day.
  2. Action Items
  3. Preparation for REST production
    1. Runs with bad BOR records
      • Third batch of processing will cover early runs, some of which had bad beginning of run records so pedestals are incorrect. Estimate is 8-10 runs.
      • Matt: Suggest that we eliminate these runs from production (for now). We agreed to this motion and Sean will pass this on to analysis team.
  4. BCAL update
    1. 2gamma systematics (Will)
      • Investigating systematics that can be applied at the shower level
      • Combinatoric background investigating by taking photons from different events. This gives qualitative agreement with background under the pi0 peak, but there are significant differences that would preclude a quantitative use at this time.
      • Investigation uses "symmetric" decays in energy and position (i.e. those that have photons close in energy and close in position)
      • Matt: Have these plots been made from MC? No, but it is on the to-do list
      • Pi0 peak varies between 129 and 136 MeV. The low values are associated with hits in the upstream end of the calorimeter. Photons downstream seem to be stable at about the pi0 mass.
      • Studies will continue.
  5. FCAL update
    1. Efficiency Studies (Jon)
      • Purpose of study is to determine the efficiency for photons hitting the Fcal.
      • Study compares data to MC
      • Exclusive gp->g omega, omega->pi0 g, study efficiency for bachelor photon. Does not appear to have sufficient resolution to be sensitive
      • Exclusive gp->g omega, omega->pi+pi-pi0, pi0-> 2g. Study efficiency for one photon from the pi0 decay.
      • Selection on missing photon energy in range of [-1,2] GeV and Delta theta < 5 deg.
      • Preliminar efficiencies presented as a function of photon energy and angle.
      • Comparison between efficiency plots indicates some systematic problems in the efficiency determination.
      • Elton: Should check that the Fcal trigger is not biasing result. Sean: New REST files include the trigger bits, which can be used to check trigger conditions. Also update code has improved tracking, which could help in this analysis.
      • Final look at photons in Bcal has coverage at low angles. Data could be used to study the interface between Fcal and Bcal.
  6. Calibrations
    1. Fcal (Adesh)
      • New non-linear corrections are used in the launches, but there are hard-coded constants not present in the CCDB. Adesh's private code extends the CCDB entries for additional constants
      • The original non-linear shower corrections, still used in the MC, include a scale factor, which results in pi0 peak values ~100 MeV if the new non-linear corrections are used.
      • Changes to the MC scheme is needed in order for the MC scale to match the correct pi0 mass with the new non-linear corrections.
      • Two options for these changes are possible: a) add scale parameter for MC that is one for data (i.e. treat MC and data differently), b) output Fcal digihits from MC to mc_smear. This latter option has been implemented by Bcal.
      • Gains for all runs are ready. However, non-linear corrections need to be determined for different run ranges.
    2. Bcal
      • Gain constants seem to adequate for all run ranges
      • Andrei: TDC time-walk corrections continues. Presently working on response to neutrons. This may require additional constants. Details will be reported at a later time.
  7. Reconstruction and Simulation
    • Ahmed: Checking stability of Led pulses for first run period. Variations are found, which are not understood yet.
    • Elton: Post updates in the Log Book, so that the group can provide feedback.
  8. Any other business