GlueX Start Counter Meeting, June 28, 2012

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GlueX Start Counter Meeting
Thursday, June 28, 2012
10 am EDT
JLab: CEBAF Center F326/327

Agenda

  1. Announcements
  2. Review minutes from previous meeting
  3. Mechanical Design
  4. Read-out Design
  5. Simulation: Start Counter Background Studies
  6. Contract

Communication Information

Video Conferencing

Slides

Talks can be deposited in the directory /group/halld/www/halldweb1/html/talks/2012-2Q on the JLab CUE. This directory is accessible from the web at https://halldweb1.jlab.org/talks/2012-2Q/ .

Minutes

Present:

  • FIU: Werner Boeglin
  • JLab: Eugene Chudakov, Chuck Hutton, Mark Ito (chair), Beni Zihlmann

Prototype Testing

  • Eugene asked how Werner's recent timing resolution measurements were done, with cosmics or a source. Werner used a Sr90 source with a trigger counter on the opposite side of the start counter paddle from the source. The end-point of the beta spectrum is 2.2 MeV, so the 3 mm thick start counter filters out the low energy electrons. Werner has done tests before on different counters using both cosmic rays and the Sr90 source and those have been consistent with each other.

Werner is still planning to buy two or three counters from McNeal.

Werner expressed some concern in using the relatively think VM2000 material to isolate the counters from each other. He was concerned that the thickness might add mechanical pressure and degrade the reflectivity of the edge surfaces. He will try various materials in the three-counter prototype to see if other materials do better, for example double-sided aluminized mylar.

Read-Out Design

mini coax still needed for start counter

Mechanical Design

mechanical on hold concept there look at schedule, make in october

device for assembly if central support , need something to hold things in place pneumatic pistons 3rd of august start assembly scintillators cost, platic craft 3k for 5 mcneal $700 per, 200 $ per

Contract

start on the con today, send example to werner, mark

Simulation

puneet background studies, issues to resolve 10^7 running, 5 and 50 kHz for em background

puneet will report in two weeks