July 10, 2015 PID Upgrade

Meeting Information

GlueX PID Upgrade Meeting
Friday, July 10, 2015
11 am, EDT
For those people at Jefferson Lab, the meeting will be in room F326

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Agenda

1. Announcements
   • S&T Review DIRC slide
   • DIRC2015
2. Simulation update (Roman)
3. Focusing optics and mirror status (John)
4. Mechanical structure and shipping crate (Matt)
5. Readout (Justin)
6. Planning for October review (All)
7. AOB

Minutes

Attending: JLab: Fernando, Matt, and Justin, CMU: Curtis, MIT: Mike and John, GSI: Roman and Joe

1. Announcements
   • S&T Review DIRC slide
     • This slide and a few brief statements on the status of different components were sent to Patrizia Rossi for her talk on Capital Equipment projects at the review.
   • DIRC2015
     • Justin will attend the DIRC2015 workshop in Germany to report on the GlueX DIRC design.
2. Simulation update (Roman)
   • The GSI group has been busy with a successful beam test at CERN, so no update for this week.
3. Focusing optics and mirror status (John)
   • John H has been using his mirror evaluation setup at Bates to measure the reflectivity of the ThorLab mirror
     • The measured reflectivity (~98%) is larger than the spec provided by ThorLab (~92%). Work is ongoing to understand the source of this difference.
   • Since the last meeting, it turns out the vendor in Chicago can lap our large mirror, but cannot apply some additional polishing step that we did not originally request.
     • The 3 smaller sample mirrors will be used to evaluate this procedure by:
       1. not lapping one of the mirrors
       2. lapping one of the mirrors but no additional polishing
       3. lapping and polishing the mirror
     • This should be done by the end of next week and John will then test the performance of these 3 mirrors
   • There is one additional coating step to improve the reflectivity in the UV and protect the mirrors from the water, which will be done later
     • The reflectivity measurement will have to be done after this step is complete
   • A backup plan is being considered using glass mirrors adhered to the Aluminum substrate
     • There is a 3M tape which can be used for this that will be tested at MIT with a glass mirror purchased from a company in Ohio
     • John can also measure the reflectivity of the glass mirror (planned for next week)
   • Joe encouraged the long term testing of components in water
     • Although we're not using DI water, it would be good to study these components in distilled water for a few months (reviewers may ask)
4. Mechanical structure and shipping crate (Matt)
   • John F continues to work on the shipping crate design
   • Joe reported on some good experience the Belle TOP people have had using "wire rope springs", which could be included in our design as a second damping source
5. Readout (Justin)
   • Justin is looking into the simulation to get some updated occupancy estimates etc. to put in the TDR
   • Fernando reported that the CLAS12 order for FPGAs and DAQ SSPs has already been placed, so we will need a separate order. Depending on the scale it may need to go out for bidding so it could be a different company.
   • We're waiting to hear about the schedule for the ASIC and adapter board production for CLAS12 to see if we can join their order, and if so when the money would need to be allocated
6. Planning for October review (All)
   • John added some documentation to the TDR on his simulations we used in evaluating different design choices and the different tolerances that were studied
   • Since many of us are unavailable we decided not to meet next week, but instead send e-mail updates on progress with the TDR.
   • When we meet next in 2 weeks (July 24) our goal was to have complete drafts of all the sections.
7. AOB
   • Matt confirmed with Rolf that our review is scheduled for October 14.