Dec 9, 2010 Calorimetry

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Teleconference Time: 10:30 a.m. EST

  • ESNET (Number is 8542553) and EVO session (GlueX Calorimetry meeting room)
  • JLab Phone: in CC F326 is 757-269-6337
  • Regina Phone: in LB228 is 306-585-4204
  • Athens Phone: in Christina's office is 011-30-210-727-6947
  • 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
    • Specifications for BCAL Monitoring R&D (Zisis, Elton, Christina)
    • IU will provide mechanical drawings to Athens to help design attachment and connection points.
    • IU: checking cross talk of calibration inputs across modules.
  2. Fcal construction
    • Matt to provide optimum schedule for shipping completed blocks to JLab based on technician work plan.
    • Lubomir to provide references on radiation damage of lead glass.
    • JLab decide on disposition of Fcal cables to free up space at IU. Ship all cables back to JLab for disposition.
  3. SiPMs
    • IU: simulation using geometry for summed units

Tentative Agenda

  1. Announcements
  2. Review of Action Items
  3. Calibration
    1. Requirements for BCAL monitoring: summary points and Monitoring System Requirements (Christina, Elton and Zisis)
  4. FCAL
    1. Construction Status
  5. BCAL
    1. Construction Status
  6. Simulations
    1. Readout segmentation (summing, towers vs quadrants/blocks)
    2. Reconstruction
  7. Other Updates


Attending: Elton, JOhn, Beni, Lubomir, Fernando (JLab); Matt, Ryan, Kei (IU); Christina, George (Athens); Zisis, George, Andrei (UofR).

  1. Announcements
    1. Mont is visiting UofR today and tomorrow
    2. Mini-Lehman review this week (focusing on Hall D solenoid and Hall B SVT) included only the higher levels of 12 GeV. Went well.
  2. Review of Action Items
  3. Calibration
    1. George has investigated the dynamic range of the LED, can easily vary from a low setting (about 10^4 p.e.) to 10^5 p.e at hight setting. This should be reproducible with good accuracy to within a few mV.
    2. Requirements for BCAL monitoring: summary points and Monitoring System Requirements (Christina, Elton and Zisis)
      • Two options considered: LED/wire (LED and board mounted on light guide), and LED/fiber (LED mounted outside of module, with fibers connected to light guide).
      • Substantial discussion, which will be feedback into design parameters
      • Some points follow
      • Elton: non-linearity of each array should be very similar to others at outset. However, a) the light on surface of array may vary from guide to guide b) degradation of number of pixels may occur with radiation and could lead to changes over time.
      • Temperature variations. LEDs tested ~0.5%/deg C, which is small. May need temperature sensors spread around the detector to monitor temperature changes.
      • Selection of individual LEDs into a summed output can be accomplished by multiplexing the LED signals. Fernando: the bias distribution over the module can also be used to select individual SiPMs that feed into a summed readout channel.
      • Mechanical: The LED/fiber solution is thought to be fairly fragile mechanically due to fiber connections to each light guide.
      • There is a quotation for a large test system with several hundred channels for about $8k.
  4. FCAL
    1. On shipping: Could either drive themselves or hire company. JLab has a preference to hire professional company. Regina will send information regarding shipping specifications.
      • Contract carrier will likely result in a single shipment in late spring.
    2. Radiation damage: Lubomir sent JLab reference. Updated data from Brad (to be distributed) gives 86% degradation at 4.5 krad, which is consistent with reference.
    3. Cable shipment return: John will investigate inexpensive way to pack up cables so that JLab can execute shipping.
    4. Construction Status
      1. Good progress on main activity, which is wrapping Pb blocks
      2. Cockcroft Walton Bases of new design expected middle of next week
        • Will test performance without conformal coating
        • Will check performance after coating
        • Test full assemblies before going into production on 500 units, expected by beginning of next year.
        • Mechanical support for full quadrant of detector will be used for checking bases and cable routing
        • Program 65 bases in prototype array with a pulsed LED source
        • Use bases for pmt test facility.
      3. Mechanical: Tim has promised review of support structure. Goal is to have drawings approved to start production in Jan.
      4. Radhard blocks: Decided on 145 blocks for rad hard insert. Information provided to Elton/Eugene for inclusion into ETC change request. Quote in hand valid till March.
  5. BCAL
    1. Construction Status
      • #25 completed, #26 will be completed Monday. Both stored at UofR till Jan
      • Ross starts machining 21-24 on Monday, Should be shipped in late Jan, ahead of project schedule.
  6. Simulations
    1. Readout segmentation (summing, towers vs quadrants/blocks)
      • Dan has generated plots which will be reviewed offline and presented next week at the Bcal meeting.
      • Andrei will check out Bcal reconstruction code and start looking at the readout segmentation.
    2. Reconstruction
  7. Other Updates