Oct 14, 2010 Calorimetry

From GlueXWiki
Jump to: navigation, search

Teleconference Time: 11:00 a.m. EDT

  • ESNET and EVO session
  • Phone in CC F326 is 757-269-6337
  • Phone in the Regina Videoconference Suite is 306-585-4204
  • Phone only if requested:
    • +1-800-377-8846 : US
    • +1-888-276-7715 : Canada
    • +1-302-709-8424 : International
    • then enter participant code: 77438230# (remember the "#"). Phone line by request only.

Items for followup from previous meeting(s)

  1. Monitoring
  2. SiPMs
    • IU: geometry for summed units
    • JLab: Complete testing of radiation damage to sensors, temperature dependence, etc.

Tentative Agenda

  1. Calibration
    1. Trapezoidal Lightguide Traps Guide (Athens)
    2. Calibration/Monitoring page: Monitoring R&D
  2. Announcements
    • Change of meeting time?
  3. Review of Action Items
  4. FCAL
    1. Construction Status
    2. CW Base Update Slides
  5. BCAL
    1. Construction Status
  6. SiPM update
  7. Simulations
  8. Other Updates


Attendees: Christina, Pavlos, George (Athens); John, Elton, Fernando, Beni, Tim, Yi, Eugene (JLab); Matt (IU); Will (USM@cern).

  1. Calibration
    1. Trapezoidal Lightguide Traps Guide (Athens)
      • Comparison of light guides using 50 cm baby Bcal.
      • Transmission of WC and trapezoidal guides is the same within 10% (with and without grease between guide and pmt)
      • No grease (no gap) reduced transmission by 40%.
      • Zisis: Is it easy to repeat measurement with a) 1mm gap and b) mask pmt to area of SiPM (1.2x1.2 cm2)?
      • Beni: Suggested to use a laser pointer to inspect reflectivity of light guide surfaces
      • John: Surprised at 40% loss: check alighment?
    2. Calibration/Monitoring page: Monitoring R&D
      • Eugene: LEDs are temperature dependent, so minimizing number of sources is very desirable. (Loop in fiber reduces light transmission, but becomes more stable).
      • Elton: The cal group needs to come up with some specifications on light monitoring/pulser system for Bcal.
      • Lubomir: A pulser system is also useful for quick checking of detectors.
      • Eugene: Note that monitoring of new SiPM technology may prove important.
      • Zisis: Irina and Andrei have investigated time it takes to calibrate with pi0s (and charged particles?)
  2. Announcements
    • CERN reached their 2010 goal for luminosity at 10^32 cm-2s-1.
  3. Review of Action Items
  4. BCAL
    1. Construction Status
      • Modules 21 and 22 are up to 110 layers
      • Dimensions are very good. New student crew is slower but careful
      • Fiber shipment 15 under test, shipments 16 and 17 on hand
      • Lead fine, recently relatively clean sheets used.
      • Danny has produced all the internal blocks for the module crates. Crates delivered now as needed
      • Shipment #5 (mods 16-20) scheduled for Nov 5 on a "refer" (temperature controlled) truck (new carrier Balck Knight). Truck sent to Ross for inspection and to design blocking system. Final inspection when modules are loaded.
      • Five cans of Bicron epoxy found cloudy. One sent to Bicron for inspection. [These cans will not be used unless Bicron certifies them].
  5. SiPM update
    • Yi has studied the combined afterpulsing/cross talk as a function of temperature
    • Tail of average pulse used to determine the combined effect of these to be about 10% independent of temperature.
    • Output signal of SiPM is verified to be independent of temperature.
    • Decision was made to proceed with SiPM procurement. SiPM studies will continue in parallel.
  6. FCAL
    1. Construction Status
      • Skipped for lack of time.
    2. CW Base Update Slides
      • Ten bases of new design assembled. All held 2000 V without sparking. Conformal coating added for further testing.
      • No problems found with switching noise
      • Fernando requested scope pictures of the pmt pulses
      • A writeup will be made available tomorrow. The company is waiting for the word to start assembly. JLab will review the information and give feedback to IU in the next couple of days.
      • Several tests of Cockcroft-Walton Bases shown
  7. Simulations
  8. Other Updates