July 30, 2013 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. Transmission: Report back on more transmission measurements (Shaun and Elton)
  2. FCAL cover during solenoid tests (Elton and John)

Tentative Agenda

  1. Announcements
  2. Action Items
  3. Monitoring
  4. BCAL
    1. SiPMs Update
      • Three units (SN: 80 JLab, 219 JLab, 1933 USM) were found to be "hazy" during installation onto the readout assemblies at JLab.
      • We have original photos from unit at USM after some cleaning. No degradation in performance was observed
      • Media:SiPMHaze1.JPG SiPM 1933 with "haze" at USM after cleaning
      • Media:SiPMHaze3 atJLab.jpg SiPM 1933 with "haze" at JLab during assembly
      • Media:SiPMHaze2.jpg SiPM 1933 with "haze" at JLab during assembly (zoom)
      • Likely the epoxy covering the sensor has been affected during handling. Carl is retesting them. Will keep these as spares.
  5. Reconstruction and Simulation
    1. Electrons from J/psi
  6. TDR update
  7. Calibration of Calorimeters
  8. Any other business
    • Elton will be away next Tuesday. Zisis will run the meeting.

Minutes

Attendees:John, Elton, Zach, George, David, Serguei (JLab); Christina (Athens); Shaun, Andrei (UofR); Will, Alam, Elias (USM); Matt (IU); Sean Dobbs (NW).

  1. Announcements
    • Solenoid is cold, testing expected in the next few days
  2. Action Items
  3. Monitoring
    • FCAL Concept for FCAL Monitoring Plane
    • Discussion on the latest modifications to the monitoring plane. Eljen can provide UVT material for panes and also do the machining.
    • Modifications were discussed and approved by the group. JLab will proceed with ordering the panes.
  4. FCAL
    • Cabling is half complete. Last pieces of the labyrinth are being machined at IU. Expect delivery in a couple of weeks. Cabling of upper section must wait on these pieces
    • The environmental monitoring system is making progress. All pieces are made and tested
    • Boxes are being fabricated and buttons being prepared. Expect a fully assembled system in a week.
    • PLC connections will be made once Dave Butler is freed up from his solenoid duties.
    • Elton: IU contract will be completed in August. It seems everything is on track for it to be completed.
  5. BCAL
    1. Contract
      • Danny is returning to decommission the module factory in August and the contract will be completed.
    2. SiPMs Update
      • Three units (SN: 80 JLab, 219 JLab, 1933 USM) were found to be "hazy" during installation onto the readout assemblies at JLab.
      • We have original photos from unit at USM after some cleaning. No degradation in performance was observed
      • Media:SiPMHaze1.JPG SiPM 1933 with "haze" at USM after cleaning
      • Media:SiPMHaze3 atJLab.jpg SiPM 1933 with "haze" at JLab during assembly
      • Media:SiPMHaze2.jpg SiPM 1933 with "haze" at JLab during assembly (zoom)
      • SN 1933 was tested several times, including once again before shipping to JLab (about six months after cleaning). No significant degradation in performance was observed relative to other sensors.
      • Likely the epoxy covering the sensor has been affected during handling. Carl is retesting them. Will keep these as spares.
      • Alam: The unit was cleaned with alcohol (isopropyl?) creating this haze. Since then any cleaning has been performed using distilled water.
      • Elton: After Carls tests, if they continue to show no change in performance, we replace them with newer units and will keep them as spares.
    3. Testing at Regina
      • Temperature dependence of SiPM performance continues.
      • Shaun has been away since he was at JLab and will return to working on the cosmic ray data.
  6. Reconstruction and Simulation (Sean Dobbs)
    • Electrons from J/psi
    • Sean showed slides with expected energy distributions of electrons from J/Psi decay. Energies range from 0 to 6-7 GeV.
    • There have been some discussions of consequences of overflow.
    • The ADC overflows at 4096 (12 bits). The pulse sum has more bits, but it is unclear from the present MC when individual samples overflow.
    • Serguei: There is also intrinsic non-linearity in the MPPC sensors, which must be corrected even before saturation occurs.
    • Matt: One may be able to use the capabilities of the Flash to compensate for saturated pulses by fitting to the pulse shape.
    • David: Discussions on the data format for the Flash-125 are converging on a scheme that combines the sum and timing information with the slot/channel information into two words. This allows for additional bits to be used for quality factors including information about saturation. After the discussion of the Flash-125 is settled, we may wish to revisit the format for the Flash-250 and incorporate some of their ideas.
  7. TDR update
  8. Calibration of Calorimeters
  9. Any other business