GlueX Start Counter Meeting, March 21, 2013

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GlueX Start Counter Meeting
Thursday, March 21, 2013
10 am EDT
JLab: CEBAF Center F326/327


  1. Announcements
  2. Review minutes from previous meeting
  3. Counter Construction
  4. Light pulsing system or not?
  5. Installation Document
  6. Contract

Communication Information

Video Conferencing

  • ESNet: 8542553
  • ReadyTalk Desktop Sharing
    • In addition to the SeeVogh desktop sharing we will try the Readytalk version in parallel. You will need a web browser open to view the desktop at JLab.
    1. Go to
    2. In the "join a meeting" box enter the Hall D code: 3421244
    3. Fill in the participant registration form. A random name alone is sufficient.
  • SeeVogh


Talks can be deposited in the directory /group/halld/www/halldweb/html/talks/2013-1Q on the JLab CUE. This directory is accessible from the web at .



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

Review minutes from previous meeting

We went over the minutes from the March 7th meeting.

Eric reports that he re-did the gain measurement and indeed the ×5 amplifier was there for the previous measurement. He has sent Fernando detailed information on the new measurement. Essentially the old results need to be scaled by a factor of 5.

Counter Construction

Eric heard from Chuck Hurlbut of Eljen. They have reported that their first attempt at bending scintillators for us did not work. The bars did not hold their intended shape; on cooling they relaxed back somewhat toward their original flat shape. They are exploring modifications to their procedures including make a new bending fixture and trying different temperatures. Eric will check this week with them on progress.

We should talk to Youri about the procedure that he used. FIU also had success with their bending procedure in the past. They heated the entire bar with weights used to hold the shape.

Eric is working on the desing of the asssembly jig. He has an initial concept that he will discuss with Werner.

Light pulsing system or not?

We discussed the need for a light pulsing system. We reached a consensus that there would likely not be much advantage to having one that could not be satisfied with cosmics or simply looking at noise from the SiPMs. These will tell you if the counters are alive. The start counter is not an energy measuring device so gain calibration is not a huge issues. Even if it were it would require a considerable effort to implement a system that would help with calibration.

We reached a consensus that a light pulser system does not make sense. We will proceed without one in our plans.

Installation Document

We talked about producing an installation document for planning when the start counter arrives in the Hall.

On a related issue, we discussed the commissioning target and how it interfaces with the start counter. Chuck will ask Tim about how far along plans for that target are.


Werner discovered that there was a person in the Dean's office at FIU that was sitting on the proposal. It seems to be moving now. He found that having a MOU to refer to has helped expedite the process. He assigned a nominal start date and end date for the project: April 1, 2013 to March 31, 2014.

[Added in press: Werner reports that the proposal now has an official project number and has started moving through the system.]