BCAL Reconstruction Meeting 2015-07-23

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Video Conferencing Information

Meeting Time: 11:15 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.
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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


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

Action Items

  1. Make some plots that clarify the need for implementation of "shower curvature" information into the reconstruction.
  2. Determine up/down gain ratios for spring data (Mark)
  1. High priority items
    1. BCAL and FCAL z coordinates: some are referenced to the center of the target, not the global coordinate system.
  2. Low priority items
    1. z-coordinate determination from up/down amplitude ratio
    2. Sampling fraction tables
    3. Code Cleanup
    4. BCAL - DGeometry BCAL routines (George)


  1. Announcements
  2. Action Items
  3. Commissioning Efforts
    1. Effective Velocities and Time Offsets (George)
    2. Time-walk corrections (Noemi)
    3. Layer efficiencies (Ahmed)
  4. Simulations
    1. Single-energy code (Tegan)
    2. Cosmics (Andrei)
  5. Reconstruction
    1. Shower curvature (Tegan, Andrei)
    2. pi0 mass and gamma reconstruction
    3. BCAL Clusterization (Will M.)
  6. Any other business


Attendees: Elton, David (JLab); George (Athens); Curtis, Will, Mike (CMU); Sean (NW); Tegan, Noemi (UofR)

  1. Announcements
  2. Action Items
  3. Commissioning Efforts
    1. BCAL - DGeometry BCAL routines (George)
      • We went one by one on the list of geometry values and decided on how to proceed. George will implement the consensus.
    2. Time-walk corrections (Noemi)
      • Understanding of TDC hits and their relation to the Unified hits is proving a challenge. She showed correlations between ADC and TDC times for a cosmic, beam and LED run.
      • Mike confirmed that the Unified hit is the right object to use
      • Mike noted that the time alignment does jump from run to run. The runs that Noemi was looking at were not used in the calibration. She can pick from runs that were aligned and be more confident that initial offsets are correct.
      • The web page that contains the list of runs used in the alignment.
      • Mike is also willing to calibrate other runs, such as the LED runs if Noemi will send a list.
  4. Simulations
    • Tegan completed check in of simulation code as well as updated ccdb constants for the variation=mc.
  5. Reconstruction
    1. BCAL Clusterization (Will M.)
      • At the last meeting, showed parameters of clusters and found that some had very large extensions in phi. These were investigated
      • The large phi clusters came as a result of a) cosmic events and b) inclusion of negative energies messing up the cluster positions, which in turn picked up uncorrelated hits.
      • A fix (safeguard) will be added to the clusterizer to only use positive energies.
      • Will also investigated the contribution of single-ended hits to the total energy (showers > 1 GeV). Found that they contribute between 5-8%, about double from Elton's early estimate. After verification of the effect, may wish to add these into the cluster energy.
  6. Any other business
    1. Sean: Simon has noticed recent decrease in track efficiencies pointing to the BCAL in the simulation. This could be due to recent changes in the simulation code from Tegan, but is still under investigation. Sean will give feedback to Tegan after looking into this.
    2. Elton: Would be useful to check generated vs reconstructed energies (as well as pi0 peaks) in the new simulations to verify that all changes are as expected. At the moment, Sean suggests that Tegan generate his own samples, since there aren't any large files of simulation with the latest code yet.