Aug 5, 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
   • USM: Send drawings of guides to be machined (soon). Send 4 unpolished guides to UofR and 2 unpolished guides to Athens.
   • Bcal: Testing to see if LED sources can be viewed by pmts on both sides of the module (UofR/UofA).
2. Fcal
   • Decision on rad hard detectors
   • Ashot to send type of Hamamatsu pmt used for PRIMEX
   • Elton and Ashot to meet and resolve any discrepancies between the simulations.

Discussion of Options for Radiation-Hard Insert

Options for Radiation-Hard Insert

Tentative Agenda

1. Announcements
2. Review of Action Items
3. FCAL
   1. Construction status
   2. To shashlyk or not to shashlyk.
4. BCAL
   1. Construction Status
   2. Cosmic-ray normalization runs
5. Update on SiPM radiation hardness (Elton)
6. Simulations
7. Other Updates

Minutes

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

1. Announcements
   • Zisis will run the next working group/Bcal reaodut meetings.
2. Review of Action Items
3. Calibration
   1. Athens has received light guides from USM, polished them and collecting data. Results will be reported at the collaboration meeting.
4. FCAL
   1. Construction status
      1. Progress smooth according to plan: 1300-1400 welds on straps, will check wrapping/packaging shortly
      2. Redesign of Cockcroft-Walton bases proceeding
         • Once redesigned, 10 prototypes will be made for checking
         • Begin planning for base/electronics review. Schedule has slipped by one month, which can be recovered. But do not want further slippage
         • General caution: Lead times for electronic components are stretching out, many from 12 to 60 weeks. Placing orders for long-lead items.
   2. To shashlyk or not to shashlyk.
      • No update
5. BCAL
   1. Construction Status
      1. Building modules 15 and 16, expect completion by middle of next week. Mods 13-16 will then go into the machining queue
      2. Slight snag in carpentry for next set of crates, but should be resolved
      3. Mods 9-12 shipped Tues, should arrive tomorrow
   2. Cosmic-ray normalization runs
      1. Normal operation in lab. Five points of cosmics completed. Cross checks underway. Report updated normaliation in two weeks.
6. Update on SiPM radiation hardness (Elton)
   • Description of expected doses for downstream SiPMs. (Upstream devices will receive about 5 times lower rate).
   • Time @10^8 g/s for Dark rate to increase x10 is 3.25 years (10^7 s/year) x factors
   • This corresponds to a fluence of 10^9 1MeV neutron eq/cm^2.
   • factors = self-annealing x cooling x DR/10 x temperature annealing
   • self-annealing = 2 (Measured in HallA irradiated samples, needs checking for cooled AmBe irradiated samples)
   • cooling = 3 (For non-irradiated samples DR -> 0.3 DR between 20 and 5 deg C, needs checking for irradiated samples)
   • DR/10 = 0.5, Study of degradation of threshold with dark rate. See Media:Plot threshold1.png with reference to Matt's resolution calculations
   • temperature annealing = ? (additional annealing gains by raising temp ~ 80 deg C, needs checking)
7. Comments
   • Eugene: There is a single 1x1 mm2 unit which has an anomalous x4 higher rate increase than others tested. It will be re-checked next week.
   • John: Consider changing out sensors after 3 years? Zisis: Possibly cool to -10 deg? Matt: Run at 5x10^7?
   • Matt: Cautioned that calculations of resultion do not include summing. Elton: This could increase effective dark rate contribution to shower, but lower thresholds/sum.
   • Zisis: Relative to FMs: concerned about mechanical complexity as well as sensitivity of pmts to changes in field
   • Eugene: Calculations assume that both upstream and downstream have the same rate. Lower rates in upstream sensors could reduce dependence on radiation damage.
8. Further work
   • 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.
9. Simulations
10. Other Updates