Dec 22, 2008 Calorimetry

Teleconference Time: 11:15 EST/10:15 CST

• Phone:
  • +1-800-377-8846 : US
  • +1-888-276-7715 : Canada
  • +1-302-709-8424 : International
  • then enter participant code: 39527048# (remember the "#")

Items for followup from Dec 7 meeting

1. Resolution studies (Blake)
   • Develop criteria for evaluating resolution studies
   • Study impact of inactive material at the end of Bcal on acceptance.
   • Check what configuration (thresholds, step sizes, stack? parameters for secondaries, etc) is being used for the Hall D simulations (Regina)
2. Report on the Bfield components in the region of the Bcal readout (JLab for next meeting).
3. Options for vendors delivering specific lead sheet sizes (Tim)

Documents to Review

'Scope Trace - SPMPlus 13, no bias'

'Scope Trace - SPMPlus 13, bias at 29.5V'

'Scope Trace - SPMPlus 13, laser at 2.95'

'Uniformity'

Tentative Agenda

1. Announcements
2. FCAL Update
3. BCAL Update
   1. Resolution studies (Blake)
   2. SiPMPlus uniformity results (George/Zisis)
      • see images under 'Documents to Review'
   3. Magnetic Field Update (JLab)
   4. Kuraray Visit (Elton)
4. GlueX collaboration meeting
5. Any other business

Minutes

Attending: JLab:Elton, Fernando, Tim; UofR: Andrei, Blake, George, Zisis; USM: Will; IU: Matt.

1. FCAL Update
   1. Developed draft construction schedule, iteration with Elke and Tim
   2. Joh is building 64 element prototype. Welding straps, magnetic shield tubes. Next semester student starts to work on assembly and QA. Gluing fixture under construction
   3. Completing analysis on FCAL timing, with goal of NIM paper
   4. Claire is working on calibration, estimating required statistics for accurate calibrations. Likely presentation at next collaboration meeting.
2. BCAL Update
   1. Resolution studies (Blake)
      • Poor calibration for last 20 cm of Bcal
      • Calibration data, coverage in angle and 0-4 GeV in photon energy. Take slices in z and fit cluster energy as a function of thrown energy.
      • George: Should one fit over the entire energy range, since most photons are a lower energies?
      • Will: Use model to correct for leakage, using appropriate functional form (not polynomial) for calibration.
      • Matt: Try to improve reconstruction code, especially for those showers that do not have all cells firing on far side. Use single-sided pulses to compute energy and few hits on far side to determine position. This would result in a 2-pass approach, first to find clusters with substantial energy deposition in both ends of the calorimeter and then recovering showers with limited detection on one side.
   2. SiPMPlus uniformity results (George/Zisis)
      • see images under 'Documents to Review'
      • Baseline shift of 30 mV when bias applied
      • signal exhibits oscillatory behavior, not seen in the electronic boards.
      • Low pulses, UofR to check gain required. Laser providing 10^5 photons/pulse.
   3. Magnetic Field Update (JLab)
   4. Kuraray Visit (Elton)
3. GlueX collaboration meeting
4. Any other business