Sep 11, 2012 Calorimetry

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Teleconference Time: 11:00 a.m. EST

  • ESNET (Number is 8542553) and EVO session (GlueX Calorimetry meeting room)
  • Phone connection only upon request.
    • +1-866-740-1260 : US+Canada
    • +1-303-248-0285 : International
    • then enter participant code: 3421244# (remember the "#").
    • or www.readytalk.com (and code without the #)

Participant Direct Lines

  • JLab Phone: in CC F326 is 757-269-6337 (usual room)
  • JLab Phone in CC L207 is 757-269-7084
  • Phone in the Regina Videoconference Suite is 306-585-4204
  • Athens Phone: in Christina's office is 011-30-210-727-6947


Items for followup from previous meeting(s)

  1. TDR:
    • Zisis to check in his working version to allow others to participate. Not checked in yet: Expected Performance and Monitoring.
    • Elton will work on the Bcal readout section Checked in initial draft
    • The Fcal section is completely independent and Matt can coordinate this.

Tentative Agenda

  1. Announcements
  2. Review of Action Items
  3. Talks at the Collaboration Meeting
  4. Monitoring
  5. FCAL
    1. Construction Status Photos
  6. BCAL
    1. Activities at JLab
    2. SiPM Resolution with Laser (Shaun) Media:SiPM-Laser_20120911.pdf
    3. SiPM Cosmics on Construction Module (Tegan) Media:CosmicsR.pdf
  7. USM update
    1. SiPM Update (Javiera)
  8. TDR update
    1. Instructions for the TDR (You must be logged into the wiki to access this page).
    2. See Feb 14, 2012 Calorimetry Meeting
  9. Calibration of Calorimeters
  10. Simulations/Reconstruction
  11. Any other business

Minutes

Attending: Elton, Dan, David, Yi, Beni, Tim, Eugene (JLab); Javiera, Will, Alam (USM); George, Christina, Stratos (Athens); Matt (IU); Zisis, Shawn, Tegan, Andrei (UofR).

  1. Announcements
  2. Review of Action Items
  3. Talks at the Collaboration Meeting
    • Fcal (Matt)
    • UofR work (Zisis)
    • Monitoring (Christina if available)
    • USM one or two talks? -MPPC / light guides- (Hayk?)
  4. Monitoring
    • Media:BCAL results from first 20 strips 11 09 2012.pdf
    • Tested 400 LEDs. Selected 200 LEDs for the first 20 strings
    • Output of 200 LEDs are within about 25%
    • Ready to ship out 20 strings.
    • Checking LED output with integrating light meter close to LED. Repeatability of measurements is very good.
  5. FCAL - Construction Status Photos
    1. Frame almost done and ready to ship
    2. Question to Tim: Problems with making light tight. Should we keep structure at IU and make reasonable modifications? Yes
    3. Tim, John and Matt iterated on the dark room design
      • Plan to use hard plastic for the front wall. Use hard plastic gluing with large overlaps of material for rigidity and light tightness
    4. Fcal power system shown in photos
      • One of four control chassis to power the bases, each powering 700 bases and using 7 of 8 connectors
    5. Bases.
      • Have tested all the ones that are in house. Fixing the couple of percent failures (mostly HV caps)
      • Waiting for final shipment of reworked bases from the company
    6. Eugene: How much time does it take to assemble one module? Answer: about 5 min/module for the beam test, but budgeted about 45 min /person/module in entire assembly to account for collecting material and placing blocks into array.
    7. Platform (Tim)
      • The downstream platform is ready
  6. BCAL
    1. Activities at JLab (Elton)
      • Fernando has successfully assembled and tested the pre-production readout modules.
      • They have been installed on the mini-Bcal. A preliminary look at signals on the scope show that the ringing is considerably reduced. For at 2 V LED signal, the (maximum) ringing is about 5 mV peak-to-peak, compared to 60 mV on the previous boards.
    2. SiPM Resolution with Laser (Shaun) Media:SiPM-Laser_20120911.pdf
      • SiPM bias analysis using the 2010 pre-production SiPMs (#2 and #10)
      • Plotting the SiPM output as a function of bias voltage they find (using a straight line fit to the lowest 4 points) a breakdown voltage of 70.34 V. The Hamamatsu breakdown voltage was 69.9 V, but needs to be verified by Carl Zorn.
      • Yi: Consider taking data at lower voltages; check effect of curvature near breakdown. Elton: Also check temperature at the location of the sensor
      • Measured the width of the output as a function of overvoltage and finds that the optimal point is 0.9-1.1 V above breakdown. Used a 150 ns gate to measure dark current
      • Eugene: How does the dark current depend on the width of the gate? (Poisson statistics would predict a sqrt behavior; other sources might show different behavior).
      • The dark current rms increases faster than sqrt(mean), so exhibits a non-Poisson behavior
    3. SiPM Cosmics on Construction Module (Tegan) Media:CosmicsR.pdf
      1. Attenuation and veff
        • Used module with 5 pairs of counters along the length (one on top, one on bottom) to trigger. One segment was instrumented with SiPMs and one with PMTs
        • Finds atten ~ 325 for pmts and atten ~ 440 for SiPMs. We expect a longer attenuation length for the SiPMs as their sensitivity extends into the green.
        • Finds veff ~ 17 cm/ns for both pmts and SiPMs.
      2. Time resoltuion
        • Find mip resolution with PMTs of about 410 ps; it's hard to extract the time resolution for SiPMs due to the x10 amplifier used for the SiPM signals.
        • David: Suggests to use each pair of trigger scintillators with the module to deduce its time resolution
        • Also find about 20 p.e. at the center, about 3x less than what was measured in 2010. The coupling of the SiPM is an air gap (compared to grease previously) and trapezoidal guides. This could account for about half of the lower yield in this measurement.
  7. USM update
    1. SiPM Update (Javiera)
      • Fedex is scheduled to pick up 2 boxes (520 sensors) with tested SiPMs today
      • Last shipment of sensors from Hamamatsu will be requested as soon as invoices are paid.
  8. TDR update
    1. Instructions for the TDR (You must be logged into the wiki to access this page).
      • Zisis has checked in some early sections for the Bcal and is working on the performance and monitoring section
      • Elton has checked in a section on the SiPM sensors.
      • Dedicated effort on the TDR is needed in order to have a complete draft by the collaboration meeting.
  9. Calibration of Calorimeters
  10. Simulations/Reconstruction
  11. Any other business


Attendees:

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