Jun 1, 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] https://bluejeans.com/907185247.
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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. Disable red LED string in dark room to avoid leaving it on in the future. (Adesh)
  2. Complete discussion and transition of base maintenance with JLab technical staff Met with Chris and Nick on May 17.


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

Tentative Agenda

  1. Announcements
  2. Action Items
  3. Activities during the down
    1. BCAL LED pulser data (Tegan and Zisis)
  4. FCAL update
  5. BCAL update
  6. Calibrations
    1. BCAL updates to ccdb (Mark)
  7. Reconstruction and Simulation
  8. NIM articles
  9. Any other business


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

  1. Announcements
  2. Action Items
  3. BCAL updates to ccdb (Mark)
    • Revised schedule because Mark had to leave early
    • The link provides information on the updates to the ccdb
    • Only the 4 ns offsets are entered on a run-by-run basis. All other constants are fixed for the run period
    • Timing peaks now look sharp
    • Global offsets bring ADC and TDC times together. Time is reported to the center of the shower
    • Time walk corrections added to match TDCs with ADCs. These constants can likely be improved.
    • Ready for monitoring launch
    • Elton: Noted that the attenuation length for M22S3L4 is zero. May wish to use constant from previous calibrations
    • Of particular interest may be the wiggles found in the z (track) vs z (deltat). Peak is determined using ROOT procedures. Wiggles / patterns emerge that seem to be related to intensity variations. These are probably not due to BCAL. Perhaps they are due to tracking and/or method systematics (e.g. pion/proton fractions, etc)
    • Matt: Is this seen in MC? Mark: This is the next step, not yet done.
    • Quadratic term to the z(track) vs z(delta) improves agreement with data and results in improved energy resolution (see Will below)
    • The origin of some of these anomalies is unclear. Preferably, we want these calibrations to correct only BCAL-related issues.
  4. Activities during the down
  5. BCAL LED pulser data (Tegan and Zisis)
    • Taken LED data over the last week with two goals: 1) investigate problematic channels and 2) repeat studies by Mark to look at pedestal widths to monitor SIPM deterioration. Data taken for 0-2 V overbias, 18, 10 and 5 deg C chiller setting. Also taken data for different bias channels (1, 2, 3 and 4) separately to investigate problem channels.
    • Log Entry 3474343 shows that the problematic M22 S3 L4 channel has a low pulse shape and anomalous secondary peak 35 channels (140 ns) following main peak. Will investigate later today by exchanging cables with neighbor.
  6. FCAL update (Adesh)
    • Matt, Adesh, Jon, Elton met with Nick and Chris (Fernando was unable to make the meeting).
    • Maintenance of bases and safeguards against taking data with the red light in the dark room were discussed.
    • Jon will be returning to IU and has written up procedures for testing bases
    • Chris requested that we provide detailed information on the power supply (will get them from Paul)
    • For the red light in the dark room, it was decided to add a test into the alarm system that would notify shift personnel.
  7. FCAL calibration (Adesh)
    • Newest timing offsets have lead to problems in the reconstructed times. It is assumed this is due to the new 4 ns offsets added to ccdb, but mechanism is unclear. Problems develop after run 30808. Adesh plans to remove 4 ns offsets before the monitoring launch tomorrow to verify that timing anomalies are due to this. If so, the production run will be conducted with all "4 ns" offsets see to zero.
    • Except for this timing offset, all other constants are ready for production.
  8. FCAL geometry (Matt)
    • The actual distance between blocks is 4.016 cm (not 4 cm). This leads to 2-3 MeV changes to pi0 peak between 1-4 GeV. After the geometry is changed, the non-linear corrections will need to be redone. The geometry files need to be corrected, but will probably not be completed before the production launch.
  9. FCAL. Work at IU
    • Joe and Jarrod will be working at IU this summer
    • Joe will work on obtaining a better time for each cluster (at the moment the cluster time is determined from the most energetic block). He will start by studying the times from LED pulser runs.
    • Data were taken recently with a range of LED intensities, which can be used to study time walk and other timing effects.
    • He will then look at the timing of the two photons from a single pi0.
    • Jarrod will be looking at the LED data taken during the spring run to investigate stability of data, pedestals, etc.
    • Tables will be developed that provide an efficiency as a function of time per block. This will be included into the ccdb at the appropriate level based on what found.
    • Matt: Work is proceeding to incorporate various corrections from the ground up to avoid ad hoc corrections if possible.
  10. Updates from UofR
    • Andrei: Working on time calibrations, but not completed yet
    • Ahmed: Looking at LED data that Tegan is taking, but no update at this time.
  11. NIM articles
    • Fcal: Adesh is working on NIM article in time between calibrations
    • Bcal: Zisis - paper is waiting on updates from Mark/Will/George regarding calibrations.
  12. Any other business