May 7, 2015 Calorimetry

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Video Conferencing Information

Meeting Time: 11 a.m.

  1. To join via a Web Browser, go to the page [1]
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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. Work with Hovanes to activate VME LED pulser setup for FCAL (Elton). Postpone till mid May, after current run. Elton has been in contact Orlando and with Chris Williamson from the computer center to help sort out authentication.


  1. FCAL HDFCAL log book
  2. BCAL HDBCAL log book
  3. BCAL Action Items and Working Tasks

Tentative Agenda

  1. Announcements
  2. Collaboration Meeting
  3. Action Items
  4. Spring Run
  5. FCAL Update
  6. BCAL Update
  7. Summer plans
  8. Reconstruction and Simulation
  9. Calibration
  10. Any other business


Attendees: Matt, Elton, Will, Mark, Manuel (JLab); Zisis, Tegan, Ahmed, Noemi (UofR); Christina, George (Athens); Sean (NW);

  1. Announcements
  2. Collaboration Meeting
    • Move Fcal to last talk.
  3. Action Items
    • Expect to move Fcal pulser to VME this summer.
  4. Spring Run
    • Accumulated approximately the same number of pi0s this spring as last fall
  5. FCAL Update (Matt)
    1. Hardware
      • Manuel has summarized the hardware performance of the bases and Matt is digesting the information
      • Failures roughly at rate as last fall. No acceleration of problems and no surprises.
      • Some bases are reading back at 2000 V, appear to be control issues
      • Some at high current, but no HV sag. Some have been checked by Paul Smith at IU using an infrared camera and found assembly problems under components
      • Number of problems is about 2 dozen
    2. Calibration
      • Gain factors were determined last fall: Using the monitoring smoothing algorithm initial gains were determined and input into the pi0 minimization program (Jon Zarling)
      • Adesh used these constants with the spring run and finds a pi0 peak of about 11 MeV.
      • Jon is now running through all runs and will be here next week
    3. Summer program. We had an impromptu meeting at JLab yesterday and discussed the following list of projects
      • Energy resolution + systematic studies of energy resolution (vs. energy, non-linearities, etc)
      • Specification for new flash firmware. Work on a design document together with other systems
      • Get sample of electrons to various studies
      • Fcal timing algorithms
      • Develop a model for noise in the MC
      • Study of how Fcal affects trigger efficiency
    4. Comments/questions
      • Mark: What is the range of gains found? Matt: Up to factors of two. Would like to eventually update HVs to equalize the gains in hardware
      • Mark notes that some of the software he has developed for noise studies in the Bcal could be useful for the Fcal as well.
  6. BCAL Update
    1. Noise studies (Mark)
      • Studies to quantify noise from non-signal sources that affect data
      • Pedestal and LED data have been taken by scanning the bias voltages of the SiPMs
      • Finding that the dominant source of noise comes from determination of the pedestal (from a single event) and subtraction over the width of the signal.
      • Various options discussed: Using multiple events to determine pedestal; increasing the number of samples to determined the pedestal
      • Sean: Can one use the statistical average of many events: Mark: the single event seems to be limited by number of samples used; an entire run is probably too long as the characteristic time scale is the 3.5 hour temperature cycle in the hall.
      • Expect new log entries soon.
    2. George
      • Back in Greece and making progress on the determination of veff and time offsets. Expect to have something on veff to present at the next meeting
    3. Noemi
      • Back at Regina. Working on understanding the the functional form for time-walk corrections derived from the known (parameterized) pulse shape.
    4. pi0 Calibrations (Will)
      • See Log Entry 3339193
      • Used five production runs with non-zero field
      • Signal to background is improved relative to last fall. Reason is unclear, but trigger has been optimized
      • Mass resolution about 10 MeV for Eg>0.75 GeV
      • See an eta peak at higher mass at about the right mass and sigma about 30 MeV
      • Also run 2931 (800 A) has better signal to background than other runs. Unclear why. Reconstruction uses charged tracks only as veto for charged showers and vertex reconstruction
      • Jobs have been submitted for no-field runs
  7. Summer plans
  8. Reconstruction and Simulation
    • Tegan's HDGEANT and mcsmear questions
    • Discussion about defaults. Currently we are running at Vover=1.4 V, T=10C. But parameters should be easy to adjust in the simulation
    • Mark: Based on measurements, we will need to add resolution parameters in the ccdb so that simulations can be tailored on an individual bases
    • Will investigate how this is done for other subsystems
    • Poisson statistics: The gain factors are attenuated to the end of the module.
    • Tegan: When should the data structure be changed? There are arguments to go ahead and do this first, might save effort.
    • Question about adding information to the data structure to output up/down, veff lambda. Decided that Tegan would send e-mail to David to request feedback and Mark would also talk to David to come up with a strategy
    • Tegan: Should the old code be removed or essentially commented out. Matt: suggests to remove for clarity and let svn keep the historical record. Sean concurs.
  9. Calibration
  10. Any other business