[Halld-pid] Start Counter Meeting Minutes, January 23, 2014

[Mark Ito]

Yo,

Find the minutes below and at:

https://halldweb1.jlab.org/wiki/index.php/GlueX_Start_Counter_Meeting,_January_23,_2014#Minutes 
.

   -- Mark
_____________________________________

GlueX Start Counter Meeting, January 23, 2014
Minutes

    Present:
      * FIU: Werner Boeglin, Eric Pooser
      * JLab: Mark Ito (chair)

Construction

    Eric gave the report.
      * McNeal will ship the machined scintillator counters starting
        tomorrow. The first shipment should arrive by the end of next week.
      * Assembly jig progress
           + The material for the clear cast acrylic rings for the assembly
             jig have been ordered. The rings will be machined by an
             outside vendor, [25]Faulkner of Miami. It should take about a
             week to do the job. They will cut four rings, 8.5 in. OD, 8.0
             in. ID, 1.0 in. thickness, with 30 tapped holes.
           + Eric is looking into two USB cameras to get a good look at
             alignment with the SiPMs.
           + The type of the pneumatic cylinders has been finalized. Also
             the valves have been chosen. A vendor has been identified:
             [26]Bimba Manufacturing.
      * The design of the wrapping template is complete and the job
        submitted to the FIU machine shop. When the templates come back
        they will do some cutting practice.
      * There is possible problem with the SiPM on the scintillator test
        stand. This is still to be confirmed.
      * The current plan is the wrap the scintillators first, before
        testing. That will give protect them during subsequent handling. A
        study will be done to ensure that the test results are not affected
        by having the wrapping in place.

Calibration

      * Eric is working on collecting the list of calibration constants we
        will need to run the start counter.
      * He will add a leading-edge discriminator to the test set-up to
        start studying time-walk corrections.

Schedule

      * The foam for the support should arrive at JLab at the beginning of
        February.
      * The best estimate is that the start counter might be done by May.
      * Werner cautioned that until the final assembly of a few counters
        has started, it will be difficult to estimate the end date
        accurately. The time required to align the counters with the SiPMs
        is a big unknown at this point.

Data Acquisition at FIU

    Werner is planning on putting together another data acquisition at FIU.
    He would like to refresh their CODA installation.

Material Study

    Mark did a study to estimate the effect of the carbon fiber lining on
    the inner support on proton detection efficiency, as suggested by
    Eugene Chudakov. See [27]his wiki page for details.

    A material budget was collected for all significant structures from the
    beam line to the outside of the start counter and material was
    converted to scintillator-equivalent thickness. Several reactions were
    studied. Proton range and energy loss were calculated, and the
    efficiency for detection were tabulated for two distinct definitions of
    "detection."

    Typically, the presence of the carbon fiber degrades proton detection
    efficiency by about 1.5 percent for most scenarios. We thought that
    this was acceptable, given the increased strength it adds to the
    structure.

Communication Announcements

      * We will move to ESNet channel 85554 to avoid conflict with the BCAL
        meeting.
      * Mark will move the Start Counter meetings back to the PID heading
        on the Meetings wiki page.

    Retrieved from
"https://halldweb1.jlab.org/wiki/index.php/GlueX_Start_Counter_Meeting,_January_23,_2014"

References

   25. http://www.plastic-company.com/
   26. http://www.bimba.com/
   27. 
https://halldweb1.jlab.org/wiki/index.php/Start_Counter_Material_Study