July 26, 2018 Calorimeter

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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. BCAL and FCAL: Develop standard fiducial volume cuts for the calorimeters
  2. BCAL: Create non-linearity corrections for MC for gain adjustment.

Complete after new launch

  1. From Mike's work: -cos(phi) type dependence in the data and a phi dependence at the downstream end of the bcal. See Sep 21, 2017 Calorimeter Meeting.


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

Tentative Agenda

  1. Announcements
  2. Action Items
  3. Run Updates
    1. FCAL
    2. BCAL
  4. Calibrations
  5. Monitoring
  6. Reconstruction and Simulation
    1. GlueX-doc-3725 SiPM Saturation (Elton)
    2. Splitoff rejection algorithm testing and validation (Rebecca)
  7. NIM articles
  8. Any other business


Attending: Elton, Colin, Mark (JLab); Curtis, Will (CMU); Tolta (FIU); Tegan (UofR); Sean (FSU)

  1. Announcements
  2. Action Items
    • Matt suggested we add an action item to check the recent changes to the MC made by Richard, which he claims should not affect the gain. Last check on the MC was done by Matt based on simulations produce by Thomas. Colin will check with him.
  3. Run Updates
    1. FCAL (Colin)
      • Turned FCAL on on Tuesday.
      • Expected about 30 failed bases. At turn on only 2 were dead. There are now about 5 dead and another five that are intermittent.
      • Rebecca will be coming to JLab next week and will help Colin to bring the FCAL up.
      • Flash ADCs: (Colin) two dead channels + two possible. Should check to see if spares are available. Matt mentioned that there are a few FADCs that are not fully used and could be swapped with a module with a bad channel if they correspond to the same channels.
      • Colin spoke to Sasha: He is testing new firmware that should fix the 4ns problem. After testing, the new firmware may be deployed to the rest of the flashes.
    2. BCAL
      • Log Entry 3582400 Tim has reported that the cooling systems for the BCAL are fixed. A final check is needed from facilities. They should be available next week and we can try to take data.
      • Curtis: CDC is waiting for the BCAL to check gas mixture.
  4. Calibrations
    1. Calibration Dashboard
    2. BCAL pi0 calibration (Tegan)
      • Currently running new set of iterations with version 2.37 of the software.
      • Pi0 widths are not significantly improved (about 8.5% for inclusive and 5.1% for the exclusive sample). This could be due to fitting functions but it is unclear.
      • Elton: We need to see the fits and decide if apparent degradation in resolution since 2017 is just due to background and fit differences or a more fundamental reason.
      • Mark: We need to decide if new low-level calibrations will be required.
      • DocDB page with pi0 calibration information
        • Contains iteration chains from 2017 and 2018 done by Tegan. 2017 files are using the C-Matrix inversion method with exclusive pi0 events (pippimpi0). 2018 files are with either the C-Matrix inversion method or the peak-shifting method, as noted.
        • The file 'notes.txt' under 'other files' contains information about the 2018 iteration chains. They are listed in chronological order of when they were done.
        • In each main file, on the last four pages, there are plots of percent sigma vs. iteration for the whole energy range and with four different minimum shower energy cuts. There are also fits for the final iteration using these four energy cuts. On the rest of the pages, there are plots associated with each iteration, including fits to the pi0 distribution with no energy cut.
        • I'll compile a few summary slides once I'm done the iteration chains I'm currently working on, but until then, all the information should be on this DocDB page.
    3. Updates to geometry code, XML vs ccdb (Sean)
      • There has been discussion in the offline software regarding organization of the geometry. The idea is to have the nominal geometry in an xml file and keep corrections in the ccdb.
      • Sean is reorganizing the software to make this easy and has asked whether some ccdb constants are desired (needed?) for the BCAL. The suggestion is to add a deltaZ and deltaPhi variables in the ccdb, which are the only changes that could be made if the BCAL is moved. No changes to the geometry are envisioned at this time, but it seemed reasonable for Sean to add this ccdb constants at the time modifications are made for other systems.
      • Sean also asked for any feedback/input from the FCAL.
    4. 2018 plans for calibration (Sean)
      • Would like to know what will be done in advance of the Aug 8 monitoring launch (5 files per run).
      • Mark mentioned that if low-level calibrations are needed, the standard BCAL calibration plugins will be needed (5 files would be fine.)
      • Tegan: Non-linear calibrations are ready for upload. Sean requested that he be notified with new constants are uploaded. The launch can be used to check gains.
      • Sean also would like to get a 20-30% estimate of the number of pi0s needed for reconstruction. It will not be possible to skim the entire future data sets for the calibration. Therefore we need estimates for the required inclusive as well as exclusive channels.
      • Will recalled some numbers from previous calibrations.
      • See Mar 22, 2018 Meeting Notes. Quoting from the previous notes: "Will: Collected information based on calibration experience in 2017. Approximately 70M pi0s needed to complete calibration up to layer 3 with an energy cut of 0.5 GeV. For the non-linear correction one requires symmetric decays and therefore requires about x5 more statistics to determine the correction up to about 2.5 GeV. Will used about 10-20 runs in 2017 for the calibrations and about >50 runs for the non-linear corrections."
      • Elton: Estimates for the new skim files based on layer number should be evaluated.
      • Tegan: Currently using the statistics from the first run block (1 out of 7 blocks) is sufficient for calibration of layers 1,2 and 3, possibly for 4. Runs 40856 - 41105 are being used. All Layers 3 and 4 events are used. Layer 1 events are used up until the same file size as Layer 3 events is reached. The same is used for Layer 2. Should consider adding another run block to increase Layer 4 data.
      • Matt: Numbers also needed for the FCAL. Clarified that the dominant resource required is time for skimming, not the footprint of the output files. He would also like to see quality checks added to the skim to enrich the useful sample of pi0s in the skims.
  5. Monitoring
  6. Reconstruction and Simulation
    1. GlueX-doc-3725 SiPM Saturation (Elton)
      • Update on work in progress.
      • Code revisions to implement corrections and generate saturation in MC have been implemented.
      • A new table to hold these constants will need to be added to ccdb. Elton will propose a structure to Sean.
    2. Splitoff rejection algorithm testing and validation (Rebecca)
      • Nice summary of the algorithms to reject split-offs. Data and MC agreement is generally very good.
      • Discrepancies are found in the E1/E9 and the E9/E25 variables. The MC has a (unphysical peak at 1). Sean suggested that tuning of thresholds in MC could reduce the discrepancies.
      • Sean: Has the efficiency been studied as a function of photon energy? Not yet.
      • Matt: This algorithm may help with physics analyses that have large combinatorial background.
  7. NIM articles
  8. Any other business