Apr 30, 2009 Calorimetry

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Teleconference Time: 11:00 a.m. EST

  • EVO session
  • 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 previous meeting(s)

  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. Review options for import/export to Chile (loans, donations, transfers, etc.)
  3. Bfield calculations for new FCAL mag shield design to evaluate impact on pmt performance.

Documents to Review

  1. GlueX-doc-795 Bcal Readout Specs
  2. GlueX-doc-1214 SiPM Cooling

Tentative Agenda

  1. Announcements
  2. Calibration
  3. FCAL Update
  4. Simulations
  5. BCAL Fabrication
    • Preparations for construction
    • Final report on First-article fibers (Zisis)
  6. BCAL Readout
  7. Agenda GlueX-Collaboration-May-2009 Suggested list to be refined at next working group meeting
    • Fcal update
    • Timing resolution of FADCs
    • Bcal construction
    • Update on Bcal readout
    • Report on tests of first article fibers
  8. Review of Action Items


  1. Attending: JLab: Elton, Beni, Tim, Eugene; UofR: Andrei, George, Zisis, Kathryn; USM: Will, Alam, Serguei, +
  2. Announcements
    • News releases of the civil ground breaking at IU and Regina. Zisis will circulate links to the collaboration.
  3. Calibration
    • none
  4. FCAL Update
    • none. Matt is at the APS
  5. Simulations
    • Blake is just finished classes. Will resume work on reconstruction.
  6. BCAL Fabrication
    1. Preparations for construction
      • Working with Research Services on procurement prototype contract. Payment schedule defined.
      • Took position of new facilities on Monday. Pb cutter installed along with swager in press room (temporarily). Meeting with safety office at UofR determined that facilities are in good order to start work with students next week. Satellite room for swaging not yet available.
      • Swager was activated after long rest, and tested with surplus lead sheets. Measured thickness uniformity of sample from vender was very good. Danny learned how to clean swager drums and this will be done periodically.
      • Press frames are being read to ship out of UofA.
      • Positions posted for students for fall coop cycle.
      • (Elton) noted that the non-domestic source for the large contract has been approved by DOE Oak Ridge.
    2. Final report on First-article fibers (Zisis)
      • Zisis is compiling a document to summarize all measurements. Text and figures obtained from Beni.
      • Additional cross checks are in progress and will be completed in May. Estimated completion of evaluation and documentation on first-article fiber tests is end of May.
    3. Simulations of charged tracks (Andrei)
      • Requesting distribution of particles in Bcal. Plots are available from the Bcal review. Eugene suggested running through an ntuple and plot quantities of interest. Elton asked that preliminary work on distributions in various readout segments be summarized and made available.
  7. BCAL Readout
    1. Update from USM (Will)
      • Working on schedule developed for readout using fine mesh pmts.
      • Divided work into simulations and prototyping effort.
      • Coming up with a set of design goals for light collection is difficult due to the large number of parameters.
      • Alam mentioned that project has been divided among students and will present an interim report next Thursday.
      • (Zisis) Slice of Bcal (20 cm long) will be sawed off of prototype and sent to Ross machining for machining the ends. They have a cutting tool that should do the job, although it is not exactly like the one recommended by UofA shop.
    2. Update on SiPMs (electronics)
      • Discussions with SensL on proper electronics for SiPMs. Fernando will develop a list of design goals for the electronics and circulate for comments before passing on to SensL and Hamamatsu.
    3. Review of specifications for readout (Elton)
      • Elton presented the argument for developing specification requirements for the readout. The new PDE vs Rdark curve has shifted upwards somewhat due to new parameters. The curve corresponds to a threshold intermediate between 40 and 52 MeV. The new curve puts additional pressure on the performance of the SensL SiPMs at low PDE.
    4. Electronic summing of sensors before digitization? (Elton)
      • Consideration to summing analog signals would relax requirements on measurements of very small signals and reduce electronic costs. However, maintaining the same gain between summed signals may be difficult, especially if individual bias control is not available.
  8. Agenda GlueX-Collaboration-May-2009. The following items were added to the collaboration meeting agenda
    • Fcal update
    • Timing resolution of FADCs
    • Bcal construction
    • Update on Bcal readout
    • Report on tests of first article fibers
  9. Review of Action Items