June 25, 2009 Calorimetry

Teleconference Time: 11:00 a.m. EST

• EVO session
• Phone:
  • +1-800-377-8846 : US
  • +1-888-276-7715 : Canada
  • +1-302-709-8424 : International
  • then enter participant code: 39527048# (remember the "#")

Items for followup from previous meeting(s)

1. Resolution studies
   • Study impact of inactive material at the end of BCAL on acceptance.
2. Documentation on fiber first-article
3. Review calibration procedures
4. Update cost estimates
   • light guides (USM)
   • temperature stabilization (Tim and Fernando)
   • summing circuits for SiPMs (Fernando)
5. Impact of gain variations on resolution (especially for summed SiPMs) (Elton)

Tentative Agenda

1. Announcements
2. Review of Action Items
3. Calibration (George Voulgaris): Summary
4. BCAL Fabrication (Zisis)
   • Contract status
   • Construction prototype update
   • Results from First Shipment of Production Fibers
     • Method: fiber in track, both ends polished, far end blackened, near end coupled to Hamamatsu S2281 photodiode, read out via a picoammeter
     • Sample exponential fits: Media:JS008graphs.png
     • Attenuation Length by Lot Number: Media:FiberShip01.png
     • Attenuation Length for all fibers (151 tested to date): Media:cummulativehist.png
5. FCAL Update
   • MOU, sow (Elton, Matt)
6. Simulations (Sasha)
   • Backgrounds from Cerenkov light
   • Acceptance loss due to light guides
7. BCAL Readout
   1. Update from USM (Will)
   2. Cost comparisons (Elton)
   3. Discussion of Bcal Readout Review (July 21)
      1. Stefano Miscetti can participate in the review via video. A test of ESNET connection yesterday was very successful.
      2. Other reviewers? (Stepan Stepanyan and Howard Fenker ?)
      3. Tentative schedule: July 10: pre-brief material, July 16: slides for presentations.
      4. Tentative Agenda Topics: BCAL Readout Review
8. Other business

Minutes

Attendees:

1. Announcements
2. Review of Action Items
3. Calibration (George Voulgaris) -- connection with Athens did not work; talk postponed
4. BCAL Fabrication (Zisis)
   • Contract status - Regina Grants Officer (Helen Yum) returns from holidays tomorrow and Zisis will meet with her to discuss the most recent round of questions: the $7000 for facilities modifications (construction lab) will be removed from the contract as it is a bureaucratic roadblock. Regina will absorb this cost.
   • Construction prototype update
   • Results from First Shipment of Production Fibers
     • See linked plots in the above agenda. Bottom line: as fas as attenuation length goes, the first Kuraray shipment of 33,000 fibers is ok. The invoice has been approved by JLab. Test for no of p.e. start this afternoon and will be reported when available.
5. FCAL Update
   1. MOU, sow (Elton, Matt)
      • MOU has been signed
      • Sow from Regina will be used as a template for Fcal construction. Matt will start drft.
   2. Prototype
      • Pulser system using plexiglass sheet is setup. Eight sockets and switching circuits to flash LEDS in place. Goal is to have 16 blocks operational to match one FADC board.
      • PMT base redesign (Claire and one student, Tyler). Success testing functionality with old micro-controller. Will now port software to new micro-controller. Discussions with Elliott agreed to search for an ethernet to CAN bridge, so ease integration with overall Hall D slow control system.
      • Radhard blocks. Radiation training at IUCF completed. Start irradiating some blocks as early as next week. Purchasing five (minimum order) low tolerance glass blocks from Russia. Putting the order in place will take a while due to complications in the transaction. Considered using JLab to place the order, but Elton would not get to it till after the Bcal readout review. Will try placing order at IU in July so that blocks could be produced in August.
      • Trigger workshop. Matt is planning to attend and inquired about input needed from the Fcal. Will provide fitted parametric forms for pulses. Also list and describe required calibration triggers (pulsing plexiglass sheet, as well as pmt dividers), and also cosmic-ray triggers.
6. Simulations (Sasha)
   • Hits due to Cerenkov light in the guides is small.
   • Estimated background hits (downstream only) from particles producing Cerenkov light in light guides estimated at 2.5% per physics event. Coincident hits upstream-downstream is suppressed by additional factor of 250. For cases when a hit in the downstream cell exceeds 10 photons (2 photoelectrons), the typical equivalent one-sided energy deposited is about 80 MeV.
   • Geometrical acceptance (9.2 to 10.5 deg) for 6 photons from events gp -> p eta pi0pi0 is 50% (including threshold of 60 MeV). If only the threshold is applied, the acceptance is 80%.
   • Sasha has geometry files [1]. Matt and Mihajlo will run their single-photon acceptance program with/and without the light guides.
7. BCAL Readout
   1. Update from USM (Will)
      1. CNN visited the lab space at USM prior to the meeting for a piece on their work
      2. Alam demonstrated a ray-tracing program using the real-time ROOT viewer of "optically perfect" surfaces. A square shape is morphed into a toroidal section, a good model for some of the proposed light guides. This program provides quick turn-around and allows complicated shapes to be easily modeled.
      3. [Note added} Tim will provide the step files of the light guide geometries to Pedro to use as a basis for developing the geometry.
   2. Discussion of Bcal Readout Review (July 21)
      1. Stefano Miscetti can participate in the review via video. A test of ESNET connection yesterday was very successful.
      2. Other reviewers? (Stepan Stepanyan and Howard Fenker ?)
      3. Tentative schedule: July 10: pre-brief material, July 16: slides for presentations.
      4. Tentative Agenda Topics: BCAL Readout Review