December 14, 2007 Calorimetry

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Connection

  • The meeting will be held at 11:00 EST (10:00 CST)
  • ESNET No.: 8242553 (If ESNET is not an option for you, please let Zisis know in advance, so that we can patch in the telephone line below)
  • Phone:
    • +1-800-377-8846 : US
    • +1-888-276-7715 : Canada
    • +1-302-709-8424 : International
    • then enter participant code: 39527048# (remember the "#")

Agenda

  1. Previous minutes: November 29, 2007 Calorimetry
  2. Calorimetry Document Preparation
  3. FCAL Hardware/Software
    • Flash ADC Timing: see Email List Server
    • Light guides: ongoing, update
    • Low energy threshold: cosmics/Cherenkov: ongoing, update
    • Hadronic backgrounds: ongoing, update
  4. BCAL Hardware/Software
  5. FCAL-BCAL Hole: preliminary photon conversion plots with new geometry (Richard)
  6. Any other business

Minutes

Attendees: (IU) Alex, Mihajlo (UofR) George, Andrei (Athens) Christine (JLab) Elton, Tim, Carl.
Zisis was not online. Elton took minutes.

  1. Previous minutes: November 29, 2007 Calorimetry
    • No comments.
  2. Calorimetry Document Preparation
  3. FCAL Hardware/Software
    • Mihajlo has been generating gp->b_1pi0 and f_1pi0 (all neutral) final states for reconstruction studies. The learning curve on high multiplicity events is taking more time than anticipated. Hopes to have results to show soon.
    • Alex mentioned that a comparison of Mihajlo's reconstruction with his parametric simulation has been conducted and agrees well. The input of photon detection for the parametric MC was parameterized from Mihajlo's output. For a_0 and a_2 production the realistic acceptance is about 30-35% and agrees between the two analysis. This reconstruction has been updated since the collaboration meeting where a 40% reconstruction efficiency was reported.
    • The reconstructed masses of pi0 is about 10-11 MeV, eta is 35 MeV. The widths agree between full reconstruction and MC. For photons that hit the Fcal only, the pi0 width is about 7 MeV and photons that hit the Bcal only the width is about 11 MeV.
  4. BCAL Hardware/Software
    • George reported on the SiPM work. Two new results will be posted to the portal shortly. Conclusions from the Phase I tests are
      • Quality of SiPMs fell below expectations, at least for these early units
      • Factor of 2 variation in gain which is not acceptable
      • The sensor tiles showed extreme sensitivity of electronics to external parameters, such as the power supply and noise. Large pedestal widths are due mainly to the electronics.
      • Tested tiled arrays provide a proof-in-principle of use of detection over a large area, but characteristics are below specifications.
      • Carl asked for the voltage used for the reported tests: The breakdown voltate was 27.3 V, operation was about 28.8 V or about 1.5 V above breakdown.
      • SensL initially did not believe the large gain variations measured, but UofR measurements are reproducible and seem to stand up.
      • SensL has asked UofR to make further tests, specifically to check the connectivity from cell-to-cell, with they will do.
      • New detectors (advertized on the SensL web-site) are expected both at UofR and Jlab and will be re-tested. The Jlab detector group is also ordered an array that allows readout of each of the cells separately.
    • Fibers: Carl has received batch of fibers from St. Gobain (half to be shipped to UofR) early next week. Fibers from Kurary were ordered a week ago.
  5. FCAL-BCAL Hole: preliminary photon conversion plots with new geometry (Richard)
    • Richard was not available at the phone conference.
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