Sep 16, 2010 Calorimetry

Teleconference Time: 11:00 a.m. EDT

• ESNET and EVO session
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Items for followup from previous meeting(s)

1. Monitoring
2. Fcal
   • Elton and Ashot to meet and resolve any discrepancies between the simulations.
   • Tim to check on magnetic checks of non-corrosion coated shield.
   • Elton to check what to do with cables that do not meet CL2 specification. Excess? Distribute to collaborating universities?
3. SiPM decision
   • IU: 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. FCAL
   1. Notes from Matt: Excellent news on the CW front
      • Paul has a new reel of caps that hold voltage to 3 kV in air (leads soldered directly to to cap).
      • Under the microscope these look better than old caps -- less "spikey stuff" on the metallization.
      • He fully assembled one multiplier board and powered it up to 2 kV. It held 2 kV fine without any conformal coating.
4. Calibration
5. BCAL
   1. Construction Status
6. SiPM update
7. Simulations
8. Other Updates

Minutes

Attendees: Will, Serguei (USM@CERN); Elton, Beni, Fernando, John, Lubomir, Eugene (JLab); Zisis, Andrei (UofR).

1. Announcements
2. Review of Action Items
3. FCAL
   1. Notes from Matt: Excellent news on the CW front
      • Paul has a new reel of caps that hold voltage to 3 kV in air (leads soldered directly to to cap).
      • Under the microscope these look better than old caps -- less "spikey stuff" on the metallization.
      • He fully assembled one multiplier board and powered it up to 2 kV. It held 2 kV fine without any conformal coating.
4. Calibration
   • No update, but calibration of Bcal should receive a higher priority in future meetings.
5. BCAL
   1. Construction Status
      • Mid-month report submitted yesterday. A flake of epoxy got stuck on one of the presses denting a small area at layer 80.
      • Modules 19 and 20 up to 100 layers.
      • ROSS machining has started on 17 and 18 even before 19 and 20 have arrived.
      • Shipment 13-16 picked up at noon. Should arrive tomorrow. Will check for confirmation.
6. Light guides
   1. • Will asked about Athens measurements of WC vs USM guides. Zisis said that illumination was not very uniform during tests and they are trying to improve that. Preliminary measurements showed that the trapezoidal/WC ~ 0.8 - 1.0.
7. SiPM update
   • Yi is preparing 1x1 mm2 samples for irradiation and recovery at different temperatures. The plan is to irradiate them between now and Monday.
   • (Fernando) Carl is measuring the uniformity across the face of one irradiated and one non-irradiated array.
8. Simulations
9. Other Updates
   1. Will: Internal discussions are in progress regarding the statement-of-work. Will send Elton/Eugene updates with questions to further this along.
   2. Will asked if there was any feedback to Alam's presentation at the collaboration meeting.
      • Elton asked if there were any further updates on the mechanical box and environment control. Will indicated that the design has been simplfied but concept remains. Serguei mentioned that CAEN HV supplies (3 modules with 16 channels each) for the SiPM have been ordered. The ammeter they will use has 10 nA accuracy.
   3. Eugene inquired about LHC studies for using SiPMs. Serguei is meeting with CMS personnel (Ian and Yuri Musienko) and will get the latest information. They are purchasing 2000 3x3 mm2 units for pre-production testing of the units for the external calorimeter. They are looking for substitutes for the hybrid pmts and APDs. The APDS are generating spikes in response to neutrons (prob ~ 10^-3) and are generating single-tower signals as input to the trigger, which is problematic. These problem of spikes is compounded because they are using a single amplifier for two APDs
   4. Serguei mentioned that 700 Pb-glass blocks of size 40x40x400 mm3 are available from experiment WA98(?). GlueX needs radiation hard blocks. Serguei will see if any are available.