Oct 1, 2009 Calorimetry

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Meeting will be dedicated to Calibration and Monitoring

Teleconference Time: 11:00 a.m. EST

  • ESNET and EVO session
  • 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 "#"). Note: code changed 7/2/09

Items for followup from previous meeting(s)

  1. Requirement of hardware gain matching of pmts for Fcal (and also Bcal)
  2. Fcal
    • John iterating on support frame. Key load-bearing tubes, currenlty Al, could they switch to iron? Tim needs to weigh in on this one.
    • Need to discuss strategy for fabrication of boards. Paul is concerned primarily about the HV board. We should include Fernando and Chris on the discussion for suggestion of production.
    • Fastrack schedule: Matt asked if Fasttrack has a facility for "resource leveling". Does anyone know?
    • Magnetic shield tests? (Tim needs to provide feedback)
    • Eugene: Fcal activity on calibration is scheduled to start next month. We need to formally address it. Elton and Eugene working on CR to modify schedule for a few activities.
  3. Bcal
    • Web page needs to be setup for communications. A mid-month report is also due. (Zisis)
    • Two components fit for fiber attenuation (Zisis)
  4. Bcal readout
    • Provide information on FM pmt cathode diameters (Elton)
    • Slide 8: Matt Suggestion: Plot efficiency vs. a specific angle to understand behavior. (Alam)
    • Review decision on the orientation of FM pmt relative to Bfield, including tolerances due to expected field changes. (Elton, Will, Alam, Pedro)

Documents to Review

Tentative Agenda

  1. Announcements
  2. Review of Action Items
  3. Calibration/Monitoring
  4. Fcal
  5. Bcal
  6. BCAL Readout
    • SiPM testing - are we ready? (Carl and Fernando)
    • Light guide simulations (Elton)
  7. Simulation
  8. Other business


Attendees:Christina (Athens), Elton, John, Fernando, Beni, Eugene, Tim, Sasha (Jlab), Zisis, Andrei (UofR), Matt (IU), Will and Alam (USM)

  1. Announcements
    • Interviews are proceeding for the Hall D staff position and will continue for the next couple of weeks.
  2. Review of Action Items
    • Items reviewed and most addressed at some level. Followup will be detailed in action items for next meeting.
  3. Calibration/Monitoring
    • Athens is interested in defining a scope of the calibration system which matches their capabilities and expertise
    • Starting tests with plexiglass to measure uniformity and light output
    • Obtaining production costs for LED boards for use as backup information.
  4. Fcal
    1. Action Items
      • Changing Al to Fe in the support structure, Tim thought it would likely be ok, but will confirm. Also needs to check forces on structure due to magnetic forces.
      • Action item: B-field inside shield after annealing mu-metal and changing thickness from 4.5 mils to 14 mils, reduced the field inside shield from 5 G down to 2.5 G. (Field without mu-metal was 10 G for a 200 G external field). Inspecting fields with Eugene's program indicates that fields in this region may only be about 100 G. Measurements will be taken down to external fields of 100 G.
    2. Updates
      • Obtaining updated quotes from vendors: mechanical (John) and electrical (Paul).
      • Continue to test prototype, including light monitoring system. Jake is building a GEANT model to help determine the threshold energy from cosmic-ray measurements.
      • Claire has updated the micro-controller and CAN bus hardware and will shortly post a writeup on the portal. Elton suggested that they let Elliott comment on the draft.
  5. Bcal
    1. Status of construction / Readiness Review Schedule
      • Will finish matrix fabrication of construction prototype today. Tomorrow will glue on the 8 mm top plate; let glue cure for 4 days; move module to Ross machining
      • Ross machining is allocating 2 weeks to machine the construction prototype including all he features in the end-plate. Should be completed by Oct 21. Optical tests of module will the conducted on the finished module.
      • Date for the Readiness Review has been rescheduled for Nov 4.
    2. Fibre QA: Media:FibreQA_20091001.pdf
      • A small number of fibers were found damaged and set aside. Statistics will be made available over the next week. Fiber testing requires considerable more handling than fibers that go into the matrix and are therefore more vulnerable. Fibers are inspected visually on the Cu table before used in the matrix.
      • The 5th shipment of fibers is scheduled to arrive on Monday (53k fibers). After this delivery fiber shipments will consist of 24k fibers/month till completion.
      • The fiber data show batch dependencies, which are not completely understood but uncorrelated with the dye change at the factory.
      • Npe numbers are slightly higher than previous shipments. Preliminary attenuation length numbers presented for shipment number 4. Elton: As soon as these are confirmed, we should provide this feedback to Kuraray so they can incorporate the information back into their production line.
      • We need to decide on a strategy for how to use fibers with slightly different systematics into matrix construction (e.g. randomizing them in the matrix).
  6. BCAL Readout
    1. SiPM testing - are we ready? (Carl and Fernando)
      • Assembly of boards delayed till next week. Should be available upon receipt of new units
      • Five units from Hamamatsu are expected next week, units from SensL are expected at mid-month
      • Plan is to have keep the same gain for Hamamatu and SensL units for testing, but could be customized at a later stage.
      • From shower data it appears that the dynamic range for a single input to the sum of 3 is very similar to that of the summed output.
      • Carl is setting up his scanning system and is almost ready.
      • Elton: Should post the testing plan on the wiki for feedback and monitoring progress. (See Detailed plan for testing production SiPM units).
    2. Light guide simulations (Elton)
      • Media:Draw trigs 38deg.pdf Media:Draw trigs 73deg.pdf for segment #2.
      • Entrance rectangle is 3.01x4.0 cm. Exit radius is 1.35 cm. Length of trapezoid/cone is 60 cm, and length of torus is also 60 cm.
      • This configuration should be comparable to Alam's "cylindrical cone" geometry.
      • See also Effective diameter vs B field and angle from Antonelli et al., NIMA 368 (1996) 628-634.
      • Results in the table are consistent with Alams simulations for the geometric efficiencies.
      • Need to finalize a decision on the placement of the PMTs
      • Should order prototype light guides for typical configurations
      • Alam will see if Pedro can generate new orientations of the pmts at an angle of 15 deg relative to the B field.
Caption: Calculated efficiencies using GEANT3, lambda=240 cm. Number of cylinders in torus=35. Note that a 90deg bend with a mirror (reported at the review) scaled to this length is 35%.
Angle geometrical total
(deg) efficiency (%) efficiency (%)
41.3 98.8 57.2
54.4 57.2
73.0 97.4 55.3
90.1 97.4 55.2
  1. Simulation
  2. Other business