Dec 4, 2014 Calorimetry

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Video Conferencing Information

Meeting Time: 11:00 a.m.

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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. Add iron shields to top cosmic-ray counters (Elton)
  2. Check into procedure for new MOUs (Elton)
  3. Check variation of dark hits in data as a function of layer. Provide feedback about pedestals to Will (Mark)
  4. Provide initial calibration constants from cosmics for data base (Andrei)


  1. Calibration with Cosmics (Andrei)
  2. Spectra from Available Cosmic Runs (Andrei)

Tentative Agenda

  1. Announcements
  2. Action Items
  3. Preparations for beam: Checklists, Accessing Onsite Webpages From Offsite
  4. Offline Analysis Tools. Note these are linked off the main GlueX wiki page (right side)
    1. Run Info
    2. Run Conditions Tables
    3. Plot Browser
    4. Run Browser
    5. Time Series
  5. FCAL HDFCAL log book
    1. FCAL Monitoring Plots (Matt)
  6. BCAL HDBCAL log book
    1. BCAL_analysis_update (Will)
    2. Update on pedestal tracking (Tegan)
  7. Reconstruction and Simulation
  8. Calibration
  9. Any other business


Attendees: Elton, Manuel, Will, Mark, Adesh (JLab); Will (CMU); Matt (IU); Zisis, Andrei (UofR), Justin (MIT); Christina, George (Athens)

  1. Announcements
  2. Action Items
  3. Preparations for beam: Checklists, Accessing Onsite Webpages From Offsite
  4. Offline Analysis Tools. Note these are linked off the main GlueX wiki page (right side)
    1. Elton pointed out that there are many plots available online about the ongoing runs (see below)
    2. Matt noted that if the run information/run condition information was better organized it would help everyone trying to access the data. He noted that in CLEO a standard web form was filled out every run by the operator (many entries automatically) and provided much of the information that is needed. We will pass on this suggestion.
    3. Run Info
    4. Run Conditions Tables
    5. Plot Browser
    6. Run Browser
    7. Time Series
  5. FCAL HDFCAL log book
    1. A bug was introduced on Nov 24 that affected Flash 250 data. Matt worked with David to find the bug and a fix was checked in yesterday that fixed the problem.
    2. Single-hit channels (Manuel)
      • See Log entry
      • Selected events with one very large signal (>900 counts) and no others greater than 60 counts. Plotted their distribution. Some channels stand out. Lowered HV, which solved the problem for some but not all. Remaining hot channels are removed from the trigger.
      • Elton: It appears that the hot channels appear only with beam. Was it due to discharges after charging up of the glass? Manuel: Do not find them if there is no beam or light injected into detector. Checking the response under non-beam conditions may prove useful.
      • Matt: Noted that single-cell clusters are included in the analysis, but do not seem to change the distributions qualitatively.
      • Question came up regarding whether Hdview2 displays hits that have a ped=0 (i.e. failures of the time extraction algorithm). [Note Later: Matt checked the FCAL factory and verified that these hits are not passed on for display (as required).
    3. Pedestal Study (Mark) See Log 3310131
      • Find oscillations at the beginning of the window that affect pedestal. Some channels long tails at the low side; the high side is chopped of by threshold. Adesh is investigating this behavior by checking the wave forms.
      • The analysis shows that the RMS distribution is multi-modal, with small pedestals widths pertaining to crates closest to the beam. Matt: Noted that these same crates have different cables than other crates and slightly different timing delays, which may be a coincidence.
    4. FCAL Monitoring Plots (Matt)
  6. BCAL HDBCAL log book
    1. BCAL_analysis_update (Will M.)
      • Showed preliminary plots of the two-photon mass spectrum in both the BCAL and the FCAL. The selection requires 2 tracks in the event to determine a vertex. Showers are selected that do not match any tracks.
      • Finds peak in the BCAL at about 410 MeV, higher than expected for a pi0.
      • Using energy clusters that are matched to tracks: Energy deposited per layer per cm of track length was also shown, peaks at about 30 MeV/cm for layer 1 and increases monotonically to about 40 MeV/cm for layer 4. We expect a constant 10 MeV/cm. For this analysis there is a systematic bias of the reconstructed track to shorter lengths, which would bring the presented values into closer agreement
      • Mark: We are seeing two indications that the nominal calibration factors in the BCAL is about 3 times too high. The current value is 0.1 MeV/integrated count. Andrei's analysis of cosmics gives about 0.044 MeV/count for upstream and 0.036 MeV/count for downstream, or about 0.04 MeV/count average. this is 2.5 times smaller than the value used. This brings the pi0 peak and the energy deposited per layer much closer to expectations.
      • Matt: Would be interesting to investigate the dependence of the peak on the shower location and vertex positions. Will can investigate this with jobs that are running on the farm.
      • Will L: Asked what the ratio of pi0/eta was in the simulation. Will has not seen any etas in the simulation.
    2. Andrei will send a file with the calibration constants to Mark, so they can be included into the data base and used with the next iteration of reconstruction.
  7. Reconstruction and Simulation
    1. For next reconstruction meeting, we need to revisit the matching of dark hits in the simulation to data.
  8. Calibration
  9. Any other business