Sep 2, 2010 Calorimetry

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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. Fcal
    • Elton and Ashot to meet and resolve any discrepancies between the simulations.
  3. Bcal
    • Report cosmic-ray normalization of energy conversion to photons.
  4. SiPM evaluations
    • UofR: Complete cosmic-ray energy calibration.
    • IU: a) take into account 5 times lower rate in upstream compared to downstream b) geometry for summed units
    • JLab: Complete testing of radiation damage to sensors, temperature dependence, etc.

Tentative Agenda

  1. Announcements
  2. Review of Action Items
  3. Calibration
  4. BCAL
    1. Construction Status
    2. Cosmic-ray normalization runs (Media:Cal_meet100902.pdf)
    3. Brief update on SiPM tests
  5. Agenda for GlueX-Collaboration-Sep-2010
  6. FCAL
    1. Construction status
    2. To shashlyk or not to shashlyk.
  7. Simulations
  8. Other Updates


Attendees: Elton, John, Hovanes, Tim, Yi, Eugene (JLab); Matt, Ryan (IU); Zisis, Andrei (UofR); Will (USM);

  1. Announcements
    • None
  2. Review of Action Items
    • Matt expects to have results on resolution of summed channels soon
    • Elton and Ashot are scheduled to meet tomorrow to resolve differences in their simulations
  3. Calibration
  4. (Zisis) Reported that George Voulgaris is making comparisons between Winston Cone and Trapezoidal guides (from USM). Working on producing reproducible results. May have more to show at the collaboration meeting.
  5. BCAL
    1. Construction Status
      • Modules 13-16 scheduled to be machined by Sep 7. Upon successful inspection, they will be shipped on Sep 13.
      • Student crew completed their intership on Tuesday; they have performed very well and managed to regain some of the early schedule delays
      • New crew started yesterday, building new layers on Modules 19 and 20. Three experienced students are helping with transition. Stacking is resuming under careful supervision by Danny to insure continuation of quality work.
      • Pb cleaning. Some batches of lead found with more oxidation than usual. Additional cleaning with vinegar was investigated. Initial results were very promising, but oxidation returned quickly and so cleaning with vinegar has been dropped. For batches with high oxidation, dry brushing of the oxidation will be done before cleaning with ethanol (normal process).
      • Fibers: Shipment #16 has arrived. Skids were broken, but fibers survived fine. Resuming Npe measurements of shipments 12-15 (using equipment borrowed by the cosmic-ray setup).
    2. Cosmic-ray normalization runs (Media:Cal_meet100902.pdf)
      • Data taken at five positions along the length of the prototype module, with two sets of opposing pmts at two vertical locations. Each pmt was attached (using grease) to a 2x2 cm2 Winston Cone (cover about 17 layers of fibers), also connected with optical grease to the module. The top pmts are calibrated Hamamatsu pmts (one of them the R329 calibrated tube used in single fiber measurements). They viewed layers of corrected fibers. The bottom pmts are Burle pmts, viewing an area of module prior to rectifying the build. The results shown were only from the top pmts. (Preliminary look at the bottom pmts indicate somewhat degraded performance, but results are under investigation).
      • Only top counter (about 5 cm long) used to trigger. The two trigger counter pulses as well as the four pmts on the module were recorded in an ADC. Vertical tracks were selected using the pulse height information. Remaining triggers were used to monitor the pedestals throughout the relatively long periods of data taking.
      • Five positions along the length, about 90 cm between them
      • Data from all five positions were analyzed together to reduce number of parameters in fit. The four positions farthest from the tube were used in each setting to allow for a single exponent. Combining the data in this way yielded 10% uncertainties in the photoelectron normalization, about 60+/-10 photoelectrons at the center of the module, lambda~370 cm.
      • Extrapolation of yield with single fibers (assuming a 90% collection of the WC) yields about 72 photoelectrons, lambda ~ 320 cm.
      • These results imply that the scaled values from the single fiber measurements coincide with measurements on the modules, but would require an increase in the dynamic range by about 20%.
      • Results from bottom pmts are pending, and Andrei will give a summary at the collaboration meeting.
      • Matt requested a number of photoelectrons/MeV be extracted from the data.
    3. Brief update on SiPM tests
      • SiPMs (15 1x1 mm2 units) have arrived from Hamamatsu
      • Fernando has provided a preamp for the tests
      • Setup for cooling (using Peltier coolers) was assembled and tested last night to 5deg C. Condensation is a problem, which likely will require a controlled dry environment
      • Testing of virgin samples will be done soon. If completed, they can be irradiated over the weekend
      • One of the annealing tests is proposed at 60 deg C, which will require borrowing an oven from Hall A.
  6. Agenda for GlueX-Collaboration-Sep-2010
    • Confirmed draft agenda already on wiki.
  7. FCAL
    1. Mechanical
      • Finishing welds on straps (2500 completed)
      • Start wrapping of blocks next week. John has built jigs to ease assembly and minimize any wrinkles in wrapping
      • Shields can then be attached to blocks. (Tim will check on measurements of magnetic shield)
    2. Cockcroft Walton bases
      • 6-8 bases operation now and running for about 2-3 weeks. However, they had to be potted with epoxy to avoid sparking
      • 10 new bare boards with redesign should arrive in a few days, and will get stuffed as soon as they arrive to check performance.
      • The purchasing process for the 500 bases has begun. The contract will not be awarded till the design is approved by JLab. But the process has begun so that the award can be made as quickly as possible.
      • Contract with manufacturer will be for completely assembled divider. Testing will be done at IU with an automatic test setup, which is now fully developed.
      • Elton: the manufacturer should be required to provide first-article samples for complete testing before producing large quantities. Also a clear understanding of what testing the manufacturer should perform should be documented. Fermando may help with suggestions on that front.
  8. Simulations
    • No update.
  9. Other Updates