Mar 4, 2010 Calorimetry

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Teleconference Time: 11:00 a.m. EST

  • ESNET and EVO session
  • Phone in CC F326 is 757-269-6337
  • Phone in the Regina Videoconference Suite is 306-585-4204
  • Phone only if requested:
    • +1-800-377-8846 : US
    • +1-888-276-7715 : Canada
    • +1-302-709-8424 : International
    • then enter participant code: 77438230# (remember the "#"). Phone line by request only.

Items for followup from previous meeting(s)

  1. Calibration/Monitoring
  2. Fcal
    • Specify the number of Rad Hard blocks to writeup a change request to the project.
    • Investigate mechanical issues associated with supporting lead glass on top of shashlyk modules (Lubomir, Serguei). Will to send drawings of the modules.
  3. Bcal
    • Specify the normalization and dynamic range for the number of photons/GeV in showers
    • Decide on specific grouping for SiPM sums
    • Possibility of using air gap for SiPM coupling
    • Finalize shapes of "Winston guides"
  4. Simulations:
    • List of energies and angles to be simulated for the purpose of establishing the dynamic range of light to the SiPMs.

Documents to Review

Tentative Agenda

  1. Announcements
  2. Review of Action Items
  3. Calibration/Monitoring
    1. Light sources in Bcal
    2. Project schedule
      • FCAL activity Fab monitoring system 15222080 (delayed by a year in Oct)
      • BCAL activity Proc aux equipment incl. calibration 15221055
  4. FCAL
    1. Radiation Damage Inserts
      • Shashlyk option
    2. Procurement Contract
    3. Update on FEU-84-3 PMTs slides
  5. BCAL
    1. Construction Status
    2. Fibre tests Media:Shipments8and9plots.pdf
  6. BCAL Readout
    1. Simulations
    2. SiPMs
    3. Geometry for guides, sensors, cooling and cables
    4. Update on USM MOU
  7. Other business


Attendees: Elton, John, Tim, Beni, Yi, Fernando, Pedro, Eugene, Lubomir, Sasha (JLab); Matt, Ryan, Mijahlo, ? (IU); Zisis, Andrei, George (UofR); Christina, Pavols, George (Athens); Will, Serguei (USM)

  1. Announcements
    • Purchase req submitted for purchase of SiPMs
    • Earthquake update: Everyone safe, most electricity is back, situation getting back to normal at the university, communications back on, start of university classes will be delayed by 1 week.
  2. Review of Action Items
  3. Calibration/Monitoring
    1. Discussion regarding using a single LED to feed multiple channels
      • George reported that tests show it will be difficult and costly to implement due to alignment of fibers to LED. Testing uses 15 100micron fibers.
      • Christine asked the reasons for suggesting fiber distribution. Elton: 1) drift of monitor can easily be tracked if viewed by several sensors 2) multiple LED source could be used to probe dynamic range of readout
      • Testing is underway at Regina to check if near and far tubes will be sensitive to a single LED. Will continue to discuss after results are in hand.
    2. Project schedule
      1. FCAL activity Fab monitoring system 15222080 (delayed by a year in Oct)
        • Suggestion for prototype before deployment. Matt offered 2 glass blocks and pmts/dividers to use in a test setup. Will coordinate with Christina offline for most efficient means of shipment (possibly shipping electronics through Geneva).
      2. BCAL activity Proc aux equipment incl. calibration 15221055
  4. FCAL
    1. Radiation Damage Inserts
      1. Shashlyk option
        • Eugene described the two options for this new detector
        • GAMS experiment has been updated with central shashlyk modules for use in COMPAS experiment. Tolerances (50 microns) for replacement 38x38 mm2 shashlyk modules are directly compatible with lead glass. Documentation exists in the form of transparencies. Resolution of these detectors is about 6%/sqrt(E). Shower parameters selected for compatibility
        • KOPIO prototype modules (also developed for PANDA) have different sampling with very thin lead sheets. Modules are 110x110 mm2 have resolution ~3%/sqrt(E). Dividing the readout of these modules into 2x2 (i.e. 55x55mm2 segments) give sizes/Moliere radius ~ 20% different compared to lead glass. Shashlyks can stand up to a Mrad. Nominal depth of modules is 20 rad lenghts, where the lead glass is about 15 rad length. Therefore geometrical lengths and number of radiation lengths are different. Lubomir obtained prices of about $2000 per shashlyk.
        • There are many details in the comparison, including resolution using the FEU-84 pmts, change in noise suppression by using different sensors.
        • Beni warned against mixing detectors with very different rad length and/or Moliere radii. Eugene says that the differences are only of order 20%.
      2. Rad hard glass
        • Shipment of single test block to NY for polishing was successful. Other 4 blocks sent were damaged (to different degrees) in return shipment.
        • Transparency measurements of rad hard glass is more complicated than initially thought due to differences in spectral response and attenuation between the two types of glass. Initial estimate of 5.8%/sqrt(E) for the rad hard glass (compared to 5.4% for normal glass) might be optimistic.
      3. Timetable: Fcal procurements will begin in about a month. Mechanical parts should be purchased for full complement of detectors, although the incremental cost for more units is not very high. Construction of CW bases, which is the single largest cost per channel, will not start for another year. In any case, decisions should be made soon.
    2. Existing light guide contract completed by Mar 1st. Billing will be sent soon. Document to discuss low-energy threshold of calorimeter with a rough estimate of 20-30 MeV.
    3. Production procurement contract
      • Finalizhing parts for shielding to be sent out this month.
      • Hiring an assembly tech
      • Expect to be starting fabrication by Readiness Review
      • Paul has assembled first two CW bases, Claire will add firmware, assemble and test.
      • EVMS reporting and project schedule. Elton needs to iterate with project management.
      • Scheduling the Fcal Fabrication Readiness Review
    4. Update on FEU-84-3 PMTs slides
      • New PMTS look fine with slightly higher gain. Some afterpulsing, of similar characteristics to existing tubes.
      • Eugene mentioned a generic problem with this design related to instability of gain over time. This should be checked in a time test.
      • Sasha inquired whether the after pulsing should be added to the specifications?
      • Sasha indicated that his Russian colleagues might be able to be involved in the testing of new tubes if we buy them.
  5. BCAL
    1. Construction
      1. All equipment operating nominally. Builds growing within tolerances.
      2. Mod 04 to RMS today or tomorrow; Mod 05 at 50%, Mod 06 at 10%. Two new crates arrived yesterday.
      3. Mod 02 and 03 machining most likely finished.
      4. Lead tally nearly done; some discrepancies. Will communicate with JLab and Vulcan today.
      5. Enough epoxy for 2.5 months on hand, 9 gallons back ordered.
      6. Shipping insurance sorted out and waiting to meet with shippers and get new quotations.
    2. Fibres
      1. Shipment 8 done and 100 fibres from No. 9 (see above links). Means shifted for shipment 9, for both Npe and atten length. Most likely a real effect but we're checking.
    3. RMS visit: March 5.
      1. Final contract will be given to RMS tomorrow.
      2. Inspection and pictures of Mod 02 and 03 machining.
      3. Transmission uniformity test on Module 01.
    4. Fibre tests Media:Shipments8and9plots.pdf
  6. BCAL Readout
    1. Simulations
    2. SiPMs
      • Measurements at USM
      • New historgrams clearly show single photoelectron spectra for 3x3 mm2 Hamamatsu sipms.
    3. Update on USM MOU
      • Discussions with project management ongoing
  7. Other business