Aug 16, 2011 SiPM Electrical and Cooling

Action Items from previous meetings

1. Test wrapping forms (Elton) Tara and Elton used the pattern prepared by Jim and checked the fit. The pattern can be extended a couple of mm toward the narrow end of the light guide
2. Decide on how to a store sorted SiPMs in preparation for installation (Fernando and Chris) The Hamamatsu boxes will be reused.
3. Decide on cable connections for monitoring cable from Bcal wedge to patch panel. Consider electronics needed for pulsing system (Elton and Fernando)
4. Review requirement of 2.5 reduced gain reduction (Elton)
   • See Log Entry with plots or Log book See entry 1787299
   • See e-mail with comments

Tentative Agenda

1. Announcements
2. Action Items
3. Schedule, reporting, and manpower (Elton)
4. SiPM production testing (Yi)
5. Mechanical assembly (Jim)
6. Temperature compensation (Jack)
7. Electronic boards (Chris)
8. Light guide gluing setup (Scot via e-mail)

Minutes

Attending: Jack, Chris, Scot, Yi, Fernando, Elton.

1. Announcements
2. Action Items
3. Schedule, reporting, and manpower (Elton)
   • Light guides for first set have been produced and measured at USM. Some guides exceed the specifications for the length. We have decided not to accept the largest outlier, which is out by 0.3 mm. Other light guides, which are out by 0.2 mm will be accepted for this batch. We expect a shipment of the first two sets next week.
4. SiPM production testing (Yi)
   • Production testing has been completed. All passed except for one unit. Yi will send exception data to Elton to obtain a RAN number from Hamamatsu for return.
   • Have taken data on after pulsing and cross talk, but not yet analyzed. Ivan might be interested in the analysis, but is busy with the PS for another week
   • Elton: Need to consolidate data from USM into our data base. Yi: They need to summarize their data and identify outliers
5. Mechanical assembly (Jim)
   • Away this week
6. Temperature compensation (Jack)
   • Suggests that the circuit can have more flexibility if the 86KOhm 0.1% resistors are replaced by other values. Fernando: Send possible values to Chris and they can check availability to see how the schedule may be impacted.
   • Jumper boards need to be reversed for the D side.
7. Electronic boards (Fernando)
   • Readout boards have been tested on the bench with a laser. The new dynamic range of 2.47 has been achieved with the fast laser, which stresses the system. Fernando suspects that there will be improvement with Bcal data.
   • The jumpers should be updated tomorrow and the readout modules built next week. They should be ready to install on the mini-Bcal at the end of next week.
   • If the new boards are acceptable, the orders will be ready to process this fiscal year.
8. Electronic boards (Chris)
   • Everything is moving along fine
   • Dsub connection to monitoring board will need a connection for the mini-Bcal test. Chris will order cables to make the connection.
9. Light guide gluing setup (Scot)
   • The wand for the gluing fixture has been put together. However, some new adjustments will be needed. The guide pins were eliminated in favor of screws to hold the force on the light guides. However, some guidance will be needed to hold wand while the screws are screwed in. The screws also need to be made captive so as not to loose them.
   • Scot inquired about the sequence of gluing and testing. Elton: Goal is to test four modules per week, one per day and Friday to catch up. Each module will have guides glued on during the day, hooked up to the pre-production readout in the afternoon and cosmics will be accumulated overnight using the DAQ that is setup for the mini-Bcal. Groups of modules will be taken down into the hall for storage after they are tested. A detailed schedule is yet to be worked out.