[Halld-pid] Start Counter Meeting Minutes, August 23, 2012

[Mark M. Ito]

Folks,

Find the minutes at

https://halldweb1.jlab.org/wiki/index.php/GlueX_Start_Counter_Meeting,_August_23,_2012#Minutes

and below.

   -- Mark
_____

GlueX Start Counter Meeting, August 23, 2012
Minutes

    Present:
      * FIU: Werner Boeglin, Lei Guo, Puneet Khetarpal
      * JLab: Fernando Barbosa, Chuck Hutton, Mark Ito (chair), Tim
        Whitlatch, Beni Zihlmann

Prototype News

      * Chuck sent the latest drawings to Werner. Werner reviewed the
        drawings and after an exchange with Chuck, all dimensions are now
        agreed on.
      * The scintillator material (EJ-212) will be recorded on the
        drawings.
      * The scintillator material has been ordered from Eljen.
           + The dimensions are 70 mm x 600 mm x 3 mm.
           + It is made by hot pressing between stainless steel surfaces.
           + Werner will get further manufacturing details from Eljen for
             Tim's records.
      * The costs from McNeal have changed and better reflect their
        process.
           + To make the tooling: $1,500
           + To form and polish a single counter: $300
      * McNeal is order materials for the tooling.
           + The first sample that we have been testing was made with a
             jury-rigged form.
      * The final dimensions have been transmitted to McNeal.
      * Werner revisited the idea of bending the scintillator at FIU and
        sending the pieces to Eljen to use their diamond fly-cut milling
        machine. Eljen reported that they would have a problem mounting the
        bent pieces. For now we will stick with the McNeal plan.
      * Werner has received a sample of the 2-micron Mylar sheets, doubly
        aluminized. The sample looks good.

Read-Out Design

      * Puneet has been looking at the new read-out boards with an LED
        light source. So far things look good. Rise times are as seen
        before (3.2 ns). There has been a lot of consultation with Fernando
        to check that settings and behaviors are indeed nominal. Single
        photon signals have been observed.
      * We need to finalize the gain setting. This will be done after
        testing is complete. The issue is principally dynamic range. FIU
        will look at signals on a scope to study the issue.
      * The mini-coax cable arrangement (from the ST2 board to the ST3)
        board had too much cross-talk via the connectors. As a result we
        are using Lemo cables for the two read-out channels (from a single
        counter = 4 MPPCs) as a temporary measure. ST2 and ST3 will have to
        be re-designed to accommodate a different cable choice.
      * We discussed whether we need to do a full (30 channel) test of the
        read-out at FIU before shipping to JLab. More discussion needed
        here.
      * If a full test is not done, we also discussed whether we want to
        mount the ST1 and ST2 boards on the support ring at FIU or after
        shipment to JLab. Again more discussion is needed.
      * Detailed design of the distribution box will be left for latter.
        Real estate is not considered a problem.

Mechanical Design

      * Tim clarified the responsibilities we had agreed to at a previous
        meeting. JLab will be responsible for all drawings and construction
        of the inner foam shell and the aluminum (or stainless) support
        ring. FIU will be responsible for the counters themselves and any
        tooling necessary for construction and assembly. This needs to be
        corrected in the current draft of the SOW.

Contract

      * Mark has written a draft SOW and circulated it. Tim responded with
        corrections and comments.
      * Fernando estimated that the ST1 and ST2 boards will be done by the
        end of the year.
      * According to the schedule, the start counter will be installed in
        January 14, 2014.

Action Items

     1. Summarize the schedule and distribute it to the group.
     2. Make a plan for testing at FIU with an eye toward the electronics
        necessary to carry it out.

    Retrieved from
"https://halldweb1.jlab.org/wiki/index.php/GlueX_Start_Counter_Meeting,_August_23,_2012"


-- 
Mark M. Ito
Jefferson Lab (www.jlab.org)
(757)269-5295