Oct 17, 2019 Calorimeter

From GlueXWiki
Jump to: navigation, search

Meeting Time: 11:00 a.m.

  1. To join via a Web Browser, go to the page [1] https://bluejeans.com/907185247.
  2. To join via Polycom room system go to the IP Address: (bjn.vc) and enter the meeting ID: 907185247.
  3. To join via phone, use one of the following numbers and the Conference ID: 907185247.
    • US or Canada: +1 408 740 7256 or
    • US or Canada: +1 888 240 2560
  4. Upon connection all microphones are automatically muted. To unmute your mike on a Polycom or equivalent unit, enter *4. Unmuting on a computer is trivial as there is a microphone button than can be clicked.
  5. More information on connecting to bluejeans is available.

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


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

Goals for Calorimetry Group

  1. Determine preliminary photon reconstruction efficiencies as a function of E, phi and theta in data and simulation with a point-to-point precision of at least 5%.
  2. Measure systematics of pi0/eta mass calibration as a function of detector position to a precision of at east 5 MeV.
  3. Demonstrate agreement of photon reconstruction efficiency and resolution between data and simulation as a function of E, phi and theta to within 5%.

Action Items

Short term items:

  1. Investigate uniqueness tracking for efficiency calculations in calorimeters (Jon)
  2. Take a new noise measurements of the BCAL FADC baselines (Mark)
  3. Complete Calorimeter work packages

Long term items:

  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.
  2. FCAL: It has been noticed that the pi0 mass shifts when the LED pulser runs at high rate. This is still not understood. See Log Entry 3595928 and references. Several runs have been taken in raw mode. These runs exhibit the shift in pi0 mass with LED running at 1 kHz. There is a need to analyze these to try to determine the cause:
    1. 50634 - FCAL Green LED: 1kHz, 29 V, Livetime is 9%, 1.7 M events
    2. 50635 - FCAL Violet LED: 1kHz, 22 V, Livetime is 9%, 1.4 M events
    3. 50636 - FCAL Blue LED: 1kHz, 15 V, Livetime is 9%, 1.5 M events

Tentative Agenda

  1. Announcements
  2. Action Items
  3. Run Updates
    1. FCAL
    2. BCAL
  4. Calibrations
  5. Monitoring
  6. Efficiencies
  7. Simulations
  8. BCAL Machine Learning
  9. NIM articles
  10. Any other business


Attending: Elton, Mark, Jon, Colin (JLab); Tolga (FIU); Christina (Athens); Zisis, Karthik, Ahmed, Varun (Regina);

  1. Announcements
    1. Next run is a month away. First RC meeting this morning; checkout of subsystems has started.
  2. Action Items
    1. Uniqueness tracking: Colin and Matt have thought about the consequences of uniqueness tracking and do not think it will resolve the difference between omega events and the particle gun. However, during the collaboration meeting Richard Jones suggested that conversions in the detector could contribute differently to omega events and the particle gun. In the case of omegas, events with 3 or more showers are rejected (depleting the denominator) whereas in the case of the particle gun the denominator is given by the number generated.
    2. Neutral timing (Tolga): Fixed a timing issue in plots shown last time. This has been fixed and he is moving on to analyzing relevant channels while focusing on specific studies for his thesis.
  3. Run Updates
    1. FCAL
      • FCAL base test setup in the electronic lab was disassembled for the move of the lab to the EEL building and is not operational yet.
      • Need to replace 40-50 bases, which is expected for a failure rate of about ~2/week. At the moment we have about 10 good bases.
      • Chris and Nick are busy in the hall with DIRC and other activities.
      • Spare pool gets smaller as harder problems are set aside. The plan is to focus on the inner blocks first and move outward. Replacement of all bases may extend into the DIRC commissioning time.
    2. BCAL
      • Jon is learning the startup procedures for BCAL.
      • Turned on the BCAL bias and LV. The bias came up but a few LV modules overshoot and trip. Previously we have seen this behavior when the firmware was corrupted. Nick has been alerted and should fix the evaluate this problem later today.
      • Once the voltages are set, Jon will learn how to pulse individual SiPM with the LED system as part of the checklist.
      • Mark and Jon will also take pedestal width data as a function of voltage to compare with previous measurements.
      • Ahmed: Developing a list of useful runs to take before the run starts. The idea is to take pulser data along with cosmic pulsing the LEDs at two different voltages and also some data in raw data mode.
  4. Calibrations
    • Mark: Run-by-run timing calibrations for BCAL for spring 2019 have not been done. Waiting on Sean to complete global timing calibrations. Need to check with him.
    • Karthik: Gain calibration for spring 2019 is essentially complete, as reported at the collaboration meeting. Four problematic channels were found. Two of them were fixed by adjusting the fitting. Two others seem to have different calibrations from fall 2018. He has been in contact with Sean to coordinate any updates to ccdb.
    • Karthik: Non-linearity is about the same as for fall 2018. There is an overshoot of the non-linearity correction of 2-3% at 12 GeV, looking at pi0 mass as a function of the energy of a single photon.
    • Elton: Summarize gain calibrations for spring 2019 at the next meeting. Mark: Send plots around prior to the meeting so we can provide feedback.
  5. Monitoring
  6. Efficiencies
  7. Simulations
  8. NIM articles
    • Mark: The discussion of photon detection efficiencies in the NIM article is in the performance section. At the moment there is a plot from Jon's work on omegas (absolute efficiency) and Data/MC comparison for BCAL, FCAL and FCAL/BCAL using the Costhe efficiency method.
    • Mark: Working on extracting the shower energy resolution from the eta mass width (assuming position uncertainty can be ignored) using g p -> pi+ pi- eta p, eta-> gg. Increased statistics using the 2018 data shows an unexpected energy behavior in the data. It could be due to complicated kinematic behavior or resonances combined with the strong energy resolution dependence on position in the BCAL. Similar analysis for FCAL has a smoother behavior. Currently running MC for comparison.
    • Zisis will read the calorimeter sections next week and provide feedback.
  9. Any other business