Apr 25, 2013 SiPM Electrical and Cooling

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Action Items from previous meetings

  1. See if it is possible to slit the covers at the bottom for removal leaving the LED in place (Tina)
  2. Start a series of illumination tests to test the new procedures (Elton)
  3. Make 2 fixtures to locate light source and hold inner light guides into place while gluing (Jim)

Tentative Agenda

  1. Announcements
  2. Action Items
  3. Light guides (Tina)
  4. SiPM production testing (Yi)
  5. Mechanical assembly (Jim)
  6. Electronic boards and SiPM sorting (Fernando and Chris)

Minutes

Attending: Yi, Chris, Keith, Tina, Jim, Nic, Fernando, Elton.

  1. Announcements
  2. Action Items
  3. Updates (Elton)
    • Illumination test have started. Elton, Tina and Keith made some tests in the ESB. Sensitivity was not too good.
    • Elton and Tara took some data on module 47 down in the hall today. There are problems with producibility but the data have not been analyzed carefully.
    • The data will be checked further to see if there is a pattern to the problems.
    • New procedures for gluing light guides include: sanding the base of the guides, more uniform illumination from the top of the light guide, longer illumination. The amount of light reaching the base from the side is very low. The procedure includes initial illumination from the side, but then illumination from the top for 25 s, then for another 25 s to secure the LEDs.
    • Tests show that when illuminated from the top of the light guide, the base is roughly uniformly illuminated with more than 180 W/cm2 for the A guide and more than 130 W/cm2 for the K guide. The intensity knob was increased to full, which increases these numbers by about 15%. With 50 s illumination, more than 6 J/cm2 should be deposited at the base of the guide. The full cure requires 2.5 - 3.5 J/cm2
  4. Light guides (Tina and Keith)
    • New production procedures have been applied to a single side of a module with good results
    • Similar procedures are being used for replacement light guides.
    • Three modules have been worked with these updated procedures.
    • As modules are tested, they will be placed to the side for observation for several days.
    • Light guides will be glued on to new modules with these new procedures and checked for an extended period.
    • Keith: suggested to measure the intensity of the borrowed light source so that it could be used in a second station.
  5. SiPM production testing (Yi)
    • The three non-conforming SiPMs from USM were returned to Hamamatsu. The factory is evaluating the units.
  6. Mechanical assembly (Jim)
    • Fixtures for positioning of the light source guide and one to hold the single guide during test have shipped and should arrive early next week.
    • Keith and Tina will have to modify the vacuum connection on the existing wand to accommodate the new fixture.
  7. Electronic boards and SiPM sorting (Fernando and Chris)
    • Ten modules have been completed and tested
    • Cover plate will be given to Tom so that he can best position the cooling tube in the cooling plate
    • Elton: Should take one of the completed modules and do a test fit in the ESB.
    • When are the "borrowed" SiPM going to be returned? Elton will check
    • Fernando: the first sample bundle of BCAL cables has been made as an example for students that should help out with this. Carlos Salgado is providing students to help.
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