Nov 20, 2012 Calorimetry

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Teleconference Time: 11:00 a.m. EST

  • ESNET (Number is 8542553) and EVO session (GlueX Calorimetry meeting room)
  • Phone connection only upon request.
    • +1-866-740-1260 : US+Canada
    • +1-303-248-0285 : International
    • then enter participant code: 3421244# (remember the "#").
    • or www.readytalk.com (and code without the #)

Participant Direct Lines

  • JLab Phone: in CC F326 is 757-269-6460 (usual room)
  • JLab Phone in CC L207 is 757-269-7084
  • Phone in the Regina Videoconference Suite is 306-585-4204
  • Athens Phone: in Christina's office is 011-30-210-727-6947

Items for followup from previous meeting(s)

  1. Monitoring
    • Circulate for comments a concept for distributing monitoring inputs to the control boards (Elton) See e-mail
  2. Simulation
    • Add up-to-date geometry for plexiglass pane and TOF detector and rerun simulation to check photon reconstruction (Elton to see if Beni or Richard can add the geometry) Beni has agreed to do this.

Tentative Agenda

  1. Announcements
  2. Review of Action Items
  3. Monitoring (e-mail from Christina)
    • I am out of town today and cannot participate but I can report the following:
    • The plexiglas FCAL measurements came to the conclusion that the main irregularities are due to the two surfaces which are opposite the the LED's (the ones which would be touching the other quadrants) and were not polished. It seems the diffused light there close to the surface is up to 5 times more than everywhere else. So next comes the polishing of those sides and re-measurement but our technician is on strike, so we have to wait.
    • Otherwise sorting of BCAL LED's goes on and the BCAL bare Control Boards have arrived in Gva as well.
  4. FCAL
  5. USM update
  6. BCAL
    • Radiation exposure to SiPMs during Hall B beamtest (Ivan)
  7. Simulations
  8. TDR update
  9. Calibration of Calorimeters
  10. Any other business

Minutes

Attendees: Matt (IU); Tim, Elton (JLab); Zisis, Shaun (UofR); Will, Orlando, Hayk, Feranando, Alam (USM).

  1. Announcements
    • Contracts for Fcal and Bcal have been extended.
  2. Review of Action Items
  3. Monitoring (e-mail from Christina)
    • I am out of town today and cannot participate but I can report the following:
    • The plexiglas FCAL measurements came to the conclusion that the main irregularities are due to the two surfaces which are opposite the the LED's (the ones which would be touching the other quadrants) and were not polished. It seems the diffused light there close to the surface is up to 5 times more than everywhere else. So next comes the polishing of those sides and re-measurement but our technician is on strike, so we have to wait.
    • Otherwise sorting of BCAL LED's goes on and the BCAL bare Control Boards have arrived in Gva as well.
    • George and Stratos connected later. They will need to polish two sides where light is being scattered. They indicated that the measurements on the Fcal should be completed within the next week and they could report the findings at the next Cal Working group meeting.
  4. FCAL
    1. Cockcroft-Walton bases
      • Received all remaining fabricated parts. Have everything in house to complete fabrication. Should have about 2600 units already.
      • Most common failure is a transistor that fails after burn-in, but at a low rate. Do not anticipate long-term problems.
      • Waiting for the company to return extra (unused) parts in order to close out the contract.
    2. Frame
      • John is finishing metal skin around the box tubes
      • Next is the front side Al channel to hold the plexiglass sheet.
      • Building according to drawings, although simulations have not been completed. If simulations indicates a problem, the parts can be refitted.
      • The frame should be ready to ship next week. (However this may be delayed as John has been called in for jury duty)
      • Matt suggests that the assembly may be easier on the floor for better access. We need to consider this when the frame to unload the frame where it is most useful
      • Zisis: Do you anticipate challenges with shimming/leveling? Matt: Believe to have anticipated the main issues. Frame will be aligned by JLab. Insert pieces are aligned to the frame and should fit back in smoothly. The beam tube was built by the shop with deviations of less than about 15 mils, well within spec.
      • Waiting on Tim to provide feedback on dark room frame drawings.
    3. Cables
      • Finished labeling and bundling cables at IU
      • Elton should check about the status of the cables ordered by JLab. Note added by Fernando: All the new FCAL coax cables have been received for some time. We need to discuss when to label them as installation is now scheduled for the Spring. We also need to discuss installation.
  5. USM update
    1. SiPMs
      • Last shipment from Hamamatsu included commercial invoices that should have been omitted. The tax implications are large ($50k) if a workaround cannot be found. Expect resolution in the next few days.
      • Elton: Hamamatsu has provided the data from the 10 extra SiPMs. This completes the information needed to setup the jumper sheets for Bcal readout boards.
      • The latest up-to-date plots of SiPM measurements compared to specifications has not been sent. Orlarndo will provide the latest at 1.2 V above breakdown for feedback from Elton.
    2. Light Guides
      • New box with 400 units will be shipped out today. That will make 1440 shipped to JLab. Expect the next box to be shipped in about a week.
      • Elton inquired about the measurements that showed some outliers. Hayk said that all guides complied with the go-nogo gauge from JLab. Therefore, it is suspected that the outlier measurements were due to human error in the measurements. This can happen if the device is not properly focused.
      • The mean of the measurements are high relative to the specification, so Iñaki will slowly shift the distribution down to lower values. This should have the effect of minimizing any geometric interferences.
    3. SiPM database wiki
      • Elton, Orlando, Hayk and Alam made edits to the database wiki in real time after the meeting and clarified most of issues that had been highlighted. Hayk will make final edits after checking of the remaining items.
  6. BCAL
    1. Radiation exposure to SiPMs during Hall B beamtest (Ivan)
      • Ivan did not attend the meeting. Elton quickly summarized his work. The dark rate for SiPMs that were used in the beam test was remeasured. The increase in dark rate is attributed to the exposure to radiation during the Hall B beam test. During the beamtest two radiation TLD monitors were located on the mini-Bcal. They each read 3rem of neutron dose. One dosimeter read 78 rem of gamma and the other 317 rem of gamma radiation. The expected rate increase due to the neutron radiation dose is approximately 15-25 MHz, consistent with the measured 30 MHz away from the beam. Closer to the beam the rates increase to about 40 MHz and 70 MHz respectively. This is expected to be due to the gamma dose received.
    2. Measurements at Regina
      • Shaun is continuing with manual measurements of the PDE and should be able to report on that work in a couple of weeks.
  7. Simulations
    • Andrei is back working on the sampling fraction study
  8. TDR update
    • Matt has started looking at the document
    • Zisis has not had time to check the the latest on monitoring, but should be independent of any edits by Matt
  9. Calibration of Calorimeters
  10. Any other business
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