Feb 25, 2016 Calorimetry

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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. Update BCAL clusterizer to improve agreement between simulated and generated MC (Mark)
  2. Modify covariance matrix for FCAL and BCAL to correspond to the current resolution of the detectors (Matt).
  3. Change F250 simulation code to match firmware and add flexibility for new algorithms (Mike)


  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. Run Preparations
    1. FCAL Update
    2. BCAL Update
    3. BCAL LED monitoring discussion
  4. Reconstruction and Simulation
  5. Calibration
  6. gp -> ggp Some systematics on pi0 mass reconstruction and deltaT check Zhenyu Zhang, Wuhan University
  7. Any other business


Attendees: Elton, mark, Will, Zhenyu Zhang (Jane), Simon, Justin (Jlab); Matt (IU); Zisis, Ahmed, Tegan, Andrei (UofR); Christina, George (Athens); Curtis (CMU)

  1. Announcements
    • Tornado warning yesterday at about 3:30 pm. Accelerator abruptly terminated operations and sent the accelerator into restricted access. Beam has not restored till 5:30 am.
  2. Action Items:
  3. Run Preparations
    1. FCAL Update
      1. Bases
        • Changing bases on a weekly basis. Primary failure includes base HV oscillating between ON/OFF. These generate alarms and the base is turned off and marked for replacement.
        • Half a dozen bases replaced Tuesday. There are about 4-5 more that are on the replacement list.
        • Test stand being setup at JLab
        • Primary failure more is difficult to diagnose and fix, because bases can function for a substantial length of time before exhibiting its failure mode. JLab test stand should help diagnosis and turn around time. Extracting the multiplier board to ship to IU is also a possibility.
        • Request that FCAL LED data be added to the production trigger to assist in diagnosing failures
      2. Calibration (Adesh)
        • Currently iterating on the pi0 calibration using data from last week
        • Goal is to have a 2nd round of HV adjustments before "production" begins
        • Present calibration system is not scalable to full data set. At the moment, we can process about 1M pi0 per day, sufficient for one iteration. Need about 5 iterations, so it takes about a week for one calibration, instead of one day, which is necessary to keep up with data taking.
        • Justin: What is the reason for the (hardware) voltage adjustment? Matt: In addition to trigger uniformity, the readout threshold uniformity impacts energy resolution.
        • Will: The Bcal pi0 skim (based on the original Fcal skim) is useful. He will work with Adesh to see whether the skims can speed up the turn-around time.
    2. BCAL Update
      1. Mark: Bcal pedestal studies in progress. Notice drift in present data of the order of 0.5 counts. Preparing diagnostic tools for whole run.
      2. UofR
        • Andrei is wrapping up calibration for comics, and also working on time-walk corrections
        • Ahmed is coming to JLab next week for shifts. He plans to also work on LED monitoring. Suggestions include taking dedicated runs with HV and LED settings to select specific SiPM. This can be done with existing software used for Hot Checkouts before the run.
        • Will has code that can be used for analysis, including text files, which are output with individual SiPM information. These could be used as input to other analysis. Ahmed will coordinate with Will first offline, but then later in the week when they are both at JLab. Their overlap may only be for a weekend.
    3. BCAL LED monitoring discussion
  4. Reconstruction and Simulation
  5. Calibration
    1. At the calibration meeting yesterday Sean requested every subsystem evaluate parameters needed for MC. Subgroups should evaluate how to update the current parameters and whether additional parameters are needed.
    2. Each subgroup also needs to consider how to deal with dead channels. In particular the FCAL, which is regularly loosing bases, must have plan for how to incorporate this information into the analysis and MC simulation.
      • Matt: Bases that start fail should be tagged by the shift crew. End the run. Evaluate problem, turn base of if necessary. Restart run with new base off.
      • A status word for each base would be updated every run indicating the status. This information can be used offline in reconstruction, but also be used as input to the MC to match the detector performance
      • Suggest that the shift crew end the run when the base failures occur, turn the base off and restart the run, making an entry into the log book
  6. gp -> ggp Some systematics on pi0 mass reconstruction and deltaT check Zhenyu Zhang, Wuhan University. Zhenyu presented slides for the exclusive reaction gp->ggp. Discussion followed
    • Mark: Why are the exclusive pi0 peaks wider than the inclusive one used by Will? (Expect narrower distributions due to better constraints). Zhenyu: it is not understood, but could be integrating over a longer period
    • Elton: Systematic mass shifts in calibration (using inclusive data) could be caused by asymmetric background under the peak
    • Will: In 2015 at lower photon energies he does not see the change in pi0 mean down to about 200 MeV. (He will dig out relevant plots and circulate the link).
    • Matt: Another source of non-linearity is caused by zero suppression, which is slightly different for channels with different gain.
    • Mark: Suggest presenting data with photons in energy ranges (instead of lower limits). Check pi0 mass with the most recent data. Justin: New data seems to have higher background at the lower photon energies. With exclusive production kinematics constraints makes it difficult to study the behavior of low energy photons when both photons are in the same energy range.
  7. Any other business