GlueX Start Counter Meeting, August 22, 2013
GlueX Start Counter Meeting
Thursday, August 22, 2013
10 am EDT
JLab: CEBAF Center L207 (non-standard meeting room)
- 1 Agenda
- 2 Communication Information
- 3 Minutes
- Review minutes from previous meeting
- Construction Status
- Installation planning
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Talks can be deposited in the directory
/group/halld/www/halldweb/html/talks/2013-3Q on the JLab CUE. This directory is accessible from the web at https://halldweb.jlab.org/talks/2013-3Q/ .
- FIU: Eric Pooser
- JLab: Mark Ito (chair), Beni Zihlmann
Fernando wrote an email asking about a couple of issues.
Tolerance on SiPM placement
Fernando asked about the tolerance for placement of the SiPMs on the circuit board.
- We have to remind ourselves how adjustable the position of the PC board is.
- The tolerance is should be in the range of 100 to 300 microns.
- Mark will discuss this issue with Fernando.
Shipping Electronics and Technical Support
We had a wide-ranging discussion of when would be a good time to send Nick Sandoval down to FIU to help set-up the electronics. Fernando proposed September, but the counters will be far from ready for a full-system test. Eric mentioned that he has had some email dialogue with Fernando on this already. We need have a discussion involving Fernando and Werner to resolve this.
Additional Measurements on Prototype Paddles
Eric updated plots of time resolution and attenuation length from last time to include paddles 4 and 5, both initially and from 7 weeks after delivery. These two paddles were not handled with the aloe-coated gloves. The results look good, consistent with the other initial measurements, and no deterioration is seen for paddles 4 and 5.
Even in the non-aloe regions there are some visible surface imperfections. It is hard to tell visually if it is due to the on-set of crazing or buffing scratches. Eric is proposing to send one of the never-handled-with-wrong-glove counters to McNeal for them to have a look and get their reaction to these features.
Eric also showed a plot from Eljen showing light output spectra from three regions of a sample that they bent. There seems to be no significant difference in the spectra from the straight region, the near-bend region, and the bend region.
Cross-Talks Suppression and Wrapping
Eric points out that if we add two layers of VM2000 between each counter to suppress cross talk, the outer surface of the counters moves out by a millimeter or so. This is probably too much. On the other hand aluminized Mylar should do the job just as well.