Sep 24, 2015 Calorimetry

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Video Conferencing Information

Meeting Time: 11:15 a.m. (new time!)

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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. Consider developing data structures for the peak value (Mike and Mark) Mike completed this task and checked into git
  2. Produce plot of z-position resolution (George). See minutes


  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. GlueX Collaboration Meeting October 8-10
  4. Commissioning
    1. FCAL Update
    2. BCAL Update
  5. Reconstruction and Simulation
  6. Calibration
    1. Coefficients (Andrei): Media:mu_decay_e_total.pdf and Media:mu_decay_e_cell.pdf
    2. TDC offsets
    3. Event Tagging (Sean, all)
  7. Any other business


Attendees: Mark, Matt, Adesh, Eugene, elton (JLab), Sean (NWU), George (Athens), Curtis, Will M., Mike (CMU), Andrei, Zisis (Regina)"

  1. Announcements
  2. Action Items
  3. GlueX Collaboration Meeting October 8-10
  4. Commissioning
    1. BCAL Simulation (Mark)
      • Evaluating response of single photons in MC at fixed angle and energy.
      • Check to see how well photons are reconstructed
      • Close to finishing project when setup was updated to new software. Finds that updated software gives many more clusters at lower energies and this is not understood. Further checking is needed and Mark will consult with Will, who has recently updated the clusterizer code to include single-ended hits.
      • General observation 1:
        • Small angles (less than 15 deg), significant leakage ~40% found.
        • Eugene inquired about gain factors (data) vs z. Will: No significant effect found in the pi0 reconstruction
      • Comprehensive data set for mono-energetic photons will be posted soon
      • Zisis: early leakage studies show leakage at 14 deg between 6-12%. Eugene: recalls similar numbers from some early MC geometries
      • General observation 2:
        • Distributions widened about 25 deg. This is likely due to the material in the FDC
    2. BCAL const (Mark)
      • Attenuation and up/down gain anomalies seen in recent analysis have disappeared after rejecting late hits in the analysis
      • Kei is launching this weekend and all runs will be processed again. New constants should be available next week.
    3. FCAL Hardware
      • Log Entry 3352063
      • Between 30-40 bases are problematic, with voltage readback as zero after few hours of operation.
      • LED pulser data was taken to check pmt response was consistent with voltage readback.
      • R11,S4,C10 example, where the base is intermittent and turns itself on and off several times during a 2 hour run period. The base is now dead.
      • Recycling of power sometimes restores operation of bases, but other times they remain off
      • Taken 10 "dead" bases back to IU for investigation and repair
      • Since the spring run the main change has been the updating of the firmware. However, restoring old firmware to some of the bases did not eliminate the symptoms
      • Matt: Should systematically investigate and tabulate different failure modes and frequency. Failed bases should be returned to IU for Paul Smith to investigate and repair
    4. FCAL simulation (Adesh)
      • Investigating the effect on resolution for single photons due to gain and thresholds
      • Initial investigation of varying gains and thresholds on pi0 widths showed little dependence. But this is being studied in more detail with single photons
      • Also: evaluating corrections for non-linearity
  5. Reconstruction and Simulation
  6. Calibration
    1. Coefficients (Andrei): Media:mu_decay_e_total.pdf and Media:mu_decay_e_cell.pdf
      • Muons of 1 MeV are left to decay inside cal module
      • Energy distribution of electron from muon decay, plot 1
      • Energy distribution of electron in cell where muon decays, plot 2. This tends to look like the data
      • Fitting for constants may be difficult because the distribution is broad and there is no fixed constraint.
    2. TDC offsets
      1. BCAL - z-position resolution (George)
        • Runs: 3179-field on, 3138-field off, 3221-comics
        • Position resolution from ADC times
        • Matt: Try to understand contribution of tracking to observed widths. E.g. could try to select on "good" tracks
        • Mike: Note that tracking code for the three runs configuration is different
        • Elton: Resolution expected is about 7.5 cm. For R3179, this seems to be achieved for z<200 cm and it increases after that. This could be due to reconstruction systematics in the bcal.
        • Further studies of systematics of mean vs z is required
        • Sean: Need to repeat for TDC offsets? Elton: yes and this is convoluted with the time walk corrections.
      2. email from elton
        • Elton reviewed the proposal in the e-mail and it was agreed to proceed like this.
        • Mike volunteered to enter the information into the ccdb if George sent his constants, and it was agreed
        • Sean suggested that the file with input tdiff information be saved for future reference. Elton suggested posting the file with tdiff to a log file and then referencing the log file in the ccdb upload notes.
      3. George: The effective velocity constants have been uploaded to the ccdb.
    3. Event Tagging (Sean, all)
      • At the online meeting, David L. reported that he added the ability to tag events in the L3 farm.
      • Groups are encouraged to think about the usefulness of event tagging for calibration. It would require a Jana plugging to run online
      • Categories of tagged events could include inclusive pi0, single eta or omega events, etc.
      • Matt: What level of reconstruction would be available (e.g. full reconstruction?). Sean: One should define the goal for tagging and then evaluate the simplest way to achieve that goal. That would define the level of reconstruction needed. Additionally, for efficiency, one would like to coordinate tagging between all groups.
  7. Any other business