Nov 2, 2017 Calorimeter

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Video Conferencing Information

Meeting Time: 11:00 a.m.

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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. Check in the code, including scripts, that is used for recent calibrations into git (BCAL: Mark)
  2. Andrei's time calibration cod [Zisis and Elton need to suggest process for checking]
  3. Add Fcal dead channels into the MC
  4. Report back on study of eta with in FCAL [Mark]
  5. Add monitoring plots for charged particle clusterizer [Will to suggest plots and collaborate with Mark]
  6. From Mike's work: -cos(phi) type dependence in the data and a phi dependence at the downstream end of the bcal.


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

Tentative Agenda

  1. Announcements
  2. Action Items
  3. FCAL Update
    • Run preparations
    • Other updates
  4. BCAL update
    • Run preparations
    • Other updates
  5. Calibrations
  6. Reconstruction and Simulation
  7. NIM articles
  8. Any other business


Attending: Elton, Mark, Colin (JLab); Will, Curtis (CMU); Tegan, Ahmed, Andrei, Zisis (UofR); Matt (IU); Sean (NW); George (Athens).

  1. Announcements
  2. Action Items
    • eta in Fcal: Mark noted that the technology is ready. Find large widths in FCAL related to the problematic HI calibrations. Mark to re-run once calibrations for new launch are finalized.
    • charged particle clusterizer: What plots make sense? (Will). Mark: has produced various plots that might be useful, but one needs to pare down the number to a few key plots.
  3. FCAL Update
    1. Run preparations
      • Detector is now back on
      • 12 bases need replacing. Check with Chris/Nick for spares. Test if needed and provide them to Chris for replacement in the FCAL.
      • Low failure rate since turning bases back on. As of this morning, no new failed bases since checking 2 weeks ago.
    2. Calibrations
      • In preparation for next launch tomorrow
      • HV changes will be made based on the new gain constants. Wait a few weeks to check new gains and check analysis launch. Spend time to check code to prepare for HV changes.
      • Matt: Timing calibrations
      • Constants from low-intensity run used for the HI with adjustments made to smooth near-neighbor variations. Use these for the upcoming launch
      • See Log Entry 3490937
      • Time resolution is about 0.3 ns at 1 GeV for both data sets. HI slightly worse resolution than LI. These times use the new method of determining the time from the energy-weighted average time. They also require a new time-walk correction function with one more parameters (ccdb needs to be modified)
      • Plan to check in new code this afternoon in time for the monitoring launch tomorrow.
      • Colin: gain calibrations:
      • Gain constants are converging. Added one more fiducial volume cut to one of the paired photons.
      • If next iteration is unchanged, the set of gain constants can be used to update ccdb.
    3. Sean comments
      1. After last iteration, need to update non-linearity correction, which should have a small effect. Systematic remain at high energy. Matt: Note that at high energy, pi0 photons coalesce so cannot be used to determine the pi0 mass without bias.
      2. After calibration for high energy data, need to go back and recalibrate the low intensity data and 2016 with new geometry changes. 2017 Intermediate period between low and hi intensity also needs calibration. Matt points out that this is part of HI data set, so constants determined now will be used. However, small adjustments could be made based on HV changes at that time. Mark: Scale factor remains on energy scale. Colin: that is adjusted using the non-linearity correction.
      3. Mark: Should determine the gg mass at higher energy and obtain the eta mass as a consistency check of the energy scale.
  4. BCAL update
    1. Run preparations
      • Elton: BCAL was turned on
      • Tegan and Ahmed took LED data and checked that all SiPMs are operational
      • The upstream and downstream chiller systems were flushed by Josh. The upstream had some air in the lines and needed to drained. Seems ok now.
    2. Other updates
  5. BCAL Calibrations
    1. Matching efficiency (Elton)
      • BCAL matching efficiencies. At the analysis meeting yesterday, it was shown that the track matching efficiencies for BCAL decreased from about 82% for ver21 to 70% for ver23 of the code. The addition of the material maps for BCAL were suspect. Elton verified this was the case and new ccdb tables (created by Simon) reverse the material in the BCAL maps from sci-fi matrix material to air. This restores the original 82% matching efficiency.
      • This current status is proposed for the upcoming launch. We will need to work on two issues: a) why inclusion of correct material in BCAL affects the matching and b) why the matching efficiency decreased from about 85% when the charged clusterizer was included into the analysis.
      • Will: Note that before the charged clusterizer was added, it was tuned by MC, then checked with data using clean omega->p pi0pi+pi- events. The phase space of this latter reaction is limited, but allowed checks with real data.
      • Mark: Noted that for the charged clusterizer the figure-of-merit is the total number of clusters reconstructed.
    2. Position and attenuation lengths (Mark)
    3. BCAL gains using exclusive pi0 sample (Tegan)
      • BCAL exclusive pi0 calibration
      • Uses matrix inversion method. Obtain gain constants for all cells.
      • Resolution reaching values obtained using inclusive sample (Will) after 31 iterations.
      • Will: Might be a better method to determine constants for layer 4.
      • Suggestions: a) Elton: compare constants obtained for layer 4 with those produced by Andrei from cosmic-rays (presently used). b) Will: plot distribution of gains to check their spread. Original constants for 2016 had a larger spread and this was attributed to falling into local optimization minima c) Curtis: compare constants one-on-one with those in ccdb to understand improvements and changes.
      • Mark: If the two methods are arriving at the same constants, then we may be reaching a floor
      • Will: How are constants changing from one iteration to another? (Histograms are output from the minimization routines).
      • Teagan: time for one iteration depends on the use of the farm. When the farm is empty 3 iterations can be done per day.
      • Will: We should consider how to combine methods for the upcoming running periods.
  6. Reconstruction and Simulation
  7. NIM articles
    • New version addresses many comments made by Eugene. Text has been simplified in the introduction and other sections, some figures have been added. Mark has updates some of his figures. Changes have been requested from Zisis, Ahmed and Will. Zisis and Will promise updates by Monday.
  8. Any other business