GlueX Start Counter Meeting, July 25, 2013

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GlueX Start Counter Meeting
Thursday, July 27, 2013
10 am EDT
JLab: CEBAF Center F326/327


  1. Announcements
  2. Review minutes from previous meeting
  3. Chuck's Start Counter Drawings: see the slides directory
  4. Construction Status
  5. Contract

Communication Information

Video Conferencing

  • ESNet: 8542553
  • SeeVogh
    • Direct meeting link
    • Phone Bridge ID: 15 4136


  1. Dial
  2. enter access code followed by the # sign: 1833622#

Desktop Sharing

  1. Go to
  2. In the "join a meeting" box enter the Hall D code: 1833622
  3. Fill in the participant registration form.


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 .


present: Werner Böglin, Chuck Hutton, Beni Zihlmann

  1. remeasure scintillation bars delayed till Eric is back
  2. The 5 scintillator bars look very good, worst timing is in the bend region with abut 430ps resolution and much better everywhere else.
  3. One bent bar was sent to Eljen: their opinion is that the bars look nice and a good job was done on them. There is a suspicion that due to the heating in the bend region the doping has changed or got damaged and causes the degradation of the light output. This will be tested by Eljen by cutting some material out of the bend region and directly measuring its properties.
  4. Werner reported on ongoing work to develop clear ideas for wrapping the scintillators and make them light tight. Also a proper mechanism needs to be developed that can handle small adjustments in positioning the scintillator bar when being installed on the Rohacell core by means of an x-y-z table and some kind of suction mechanism to hold the bar.
  5. Construction of the final test stand will be finished by middle of August.
  6. Within the next few weeks all specifications for ordering all scintillator bars will be finalized. Expect order to go out by mid to end of August.
  7. Werner asked about the status of the SiPM. I talked to Fernando and he gave the following information
    1. All SiPMs and other material are at Jlab
    2. The individual SiPMs will not be tests however the Data sheets provided by Hamamatsu will be used the pre-select the SiPM to groups of 4 for each array.
    3. The SiPMs are surface mount and will be assembled at Jlab and then tested.
    4. All PCB boards will be tested prior to install the SiPMs on them.
    5. All SiPMs and boards will be ready by the end of August.