BCAL Reconstruction Meeting 2015-04-16

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Video Conferencing Information

Meeting Time: 11:00 a.m. EDT

  1. To join via a Web Browser, go to the page [1] https://bluejeans.com/907185247.
  2. To join via Polycom room system go to the IP Address: (bjn.vc) 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 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


  1. BCAL Reconstruction Issues
  2. BCAL Reconstruction Algorithms
  3. Will's reconstructed energy info

Action Items

  1. z-coordinate determination from up/down amplitude ratio
  2. Sampling fraction tables
  3. Code Cleanup


  1. Announcements
  2. Action Items
  3. Commissioning Status Quo
  4. Simulations
    1. Shower Curvature (Tegan, Andrei)
    2. Dark hits (Mark/Tegan)
  5. Any other business


Attendees: Elton, Mark D., Sean, David, George V., Will M. (JLab), Will L. (CMU), Tegan, Ahmed, Zisis (Regina)

  1. Announcements: George V. is at JLab and taking shifts.
  2. Action Items: see below.
  3. Commissioning Status Quo
    1. Mark reported that the pedestals change with overbias. See logentry: https://logbooks.jlab.org/entry/3332361. Beyond 1.2 V the contribution comes mostly from the SiPMs. At 1.2 V we need a 10% correction to the pedestal width. Channels are mostly grouped tightly except some that vary much more than the average. This might lead to a separate smearing factor for different layers, at least. The threshold is 5 channels above baseline, which we may be able to drop to 4 if we work at it.
    2. Will M. reported that Sasha had seen issues with the average deposited energies. It was an isolated problem that seems to be resolved by a fix committed by Sean.
    3. Elton reported that Noemi is working on the time-walk corrections, George V. on the effective speed in the fibers as well as the timing offsets. When these task are completed we will have a complete set of constants in ccdb. Ahmed is working on the efficiencies from the bias scans: plots will be available later today. [Since then, Ahmed posted a report: https://halldweb.jlab.org/doc-private/DocDB/ShowDocument?docid=2697]
  4. Simulations
    1. Shower Curvature (Tegan, Andrei): Tegan reported on the shower curvature tables. He now sees 76% of the total Points, versus 80% seen by the IU code. The position resolution on the 4th layer is worse. The tables give the mean value of the centroid and an error bar for a given impact position. Elton: our primary goal is to specify the position of the shower and corrections.
    2. Dark hits (Mark/Tegan): Mark: we should consider getting rid of the waveform code for the dark hits and go to a simple (and fast) parametrization.
    3. Elton is working on a report to study details of the bias scan, for nominal gain and vs dark rates. This understanding might help us parametrize things simply, and will allow a comparison between Elton's toy code and Tegan's simulations. [Since then, Elton posted a report: https://halldweb.jlab.org/doc-private/DocDB/ShowDocument?docid=2695]
    4. David: We need to explore how the timing gets affected by the dark hits.
  5. Any other business
    1. David reported that the e-log is has been upgraded to post run info automatically on our HDRUN logbook: https://logbooks.jlab.org/book/hdrun. This is an awesome feature, and eliminated the need for tedious and time consuming scans of the conventional logbook entries by shift takers.