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FDC Weekly Meeting

Date: October 1, 2009

Participants: Daniel, Brian, Beni, Bill, Simon, Tom, Fernando, Mark S., Mark I., Chuck, Eugene

Next Meeting: October 8, 2009 @ 1:30 p.m.

Manpower Update

 - Stephen Burnett has gone back to Hall B but we expect him to rejoin us
   as soon as Hall B physics starts up again. This might be on Monday. Brian 
   Kross will be off the project for the month of October. Our new
   technician hire, Casey Heck, will be joining the FDC effort starting

General Construction Updates

 - We are presently gearing up to begin stack construction for the
   full-scale prototype. As part of stack construction, we will do a 3D 
   voltage check with a cathode-wire-cathode configuration in an Ar-CO2 
   gas environment to nominal voltage to be sure that there are no 
   breakdown problems.  Stay tuned for details
 - The preliminary FDC stack assembly document draft is located at:
   /u/group/halld/Engineering/PRELIMINARY DOCUMENTS. The document will be
   fleshed out during the assembly procedure for the full-scale prototype.
 - o-ring update: We plan on using the nominal design for the full-scale
   prototype using a thin bead (not continuous) of instant adhesive along 
   the bottom. Bill is pursuing some other ideas to improve our future
 - We have to be out of the clean room by October 15. We are presently
   planning to move the clean tent into EEL 126. Tom Carstens will be
   taking the lead on this move and the action will start tomorrow and
   continue into next week.

Wire Frame Update

 - Wire frame P1 status:
    * The low voltage power connector was repaired by Michelle Brisiel.
      We are going to cludge up a repair to the broken card guide on the
      preamp card connector.
    * P1 is essentially ready to go for the next steps before lamination to 
      its cathode plane.
 - Wire frame P3 status:
   * Brian has replaced the 3 wires that were broken and the frame has
     been reinspected. After cleaning with alcohol and lint-free wipes and
     after sitting in the dry tent for several days, the measured currents
     were all below 100 nA.
   * We want to set up once again the test where the wires are in gas
     to see how things look. Hopefully with a new understanding of the
     o-rings, we will not have too much trouble setting this up again.
   * This frame seems nearly ready for the next steps before lamination to
     its cathode plane.
 - Wire frame P4 status:
   * On Friday we cleaned P4 with a immersion/rinse bath first of isopropyl
     alcohol and then deionized water. The frame sat in the dry room over
     the weekend. Three of the field busses drew more than 5 uA at about
     100 V. We put the frame in a dry nitrogen environment for 2 more days
     and the currents are better.Two of the busses are still in pretty
     bad shape current-wise, however one of the problematic busses went up
     to 1 kV and drew "only" 600 nA.  We are investigating.
 - To strengthen the connections of the power connections and preamp
   card connections, all boards prior to stack assembly will have
   mechanical QA work done, strengthening with epoxy, and the preamp
   card connectors will be subject to Fernando's QA test rig.
 - We need to have a dedicated meeting to design what the schedule for
   work on the Phase 3 wire winding will be. The highest priority for
   work scheduling will be doing work on upgrades of the wire winding
   facility. This includes a better strongback design, the design and
   construction of precision combs, modification to the wire winding
   table, and a list of other items with the system. Stay tuned, more
   to come.
 - The wire frame construction document is located at:
   /u/group/halld/Engineering/PRELIMINARY DOCUMENTS. We will include
   the information on the wire electroplating process shortly.
 - The parts of the jig to use for the wire electroplating operation
   are in our hands. They will be assembled as we find time.

Cathode Update

 - Progress updates:
     * The mechanical work on all cathodes is complete. We have connected
       the grounds on each panel together for two cathodes. We will continue
       the work on the remaining cathodes just before they are needed for
       stack construction.
     * Fernando is overseeing the QA electrical tests on the rigid-flex
       assemblies. We have enough in our possession to get started on the
       soldering work and the remainder should be done by the end of next
       week or so.
     * Some of the rigid-flex assemblies have failed QA and cannot be
       saved. We do not have enough for the full prototype detector. We
       will move to prepare an order for the remainder that are needed.
     * Mark S. has been working with Fernando to finalize the procedures
       for soldering the rigid-flex assemblies to the cathodes. They are
       nearly done and work is expected to begin soon on the soldering to
       the first cathode.
 - The current draft of the cathode construction document is located at:
   /u/group/halld/Engineering/PRELIMINARY DOCUMENTS.
 - Roger is pressing the Japanese company that has agreed to provide our
   board material. They have agreed to manufacture the material and it
   appears it will be delivered to JLab by the end of this year.
 - Roger needs to prepare a document for QA/stuffing/cleaning for the
   cathode boards and a similar document for the cathode daughter
   boards and ground boards.

Cosmic Ray Test Stand

 - Beni is continuing work to setup the cosmic ray telescope and test
   system in EEL 126. He is making progress on reducing the noise and is
   working to reproduce the data from the small-scale prototype that Simon
   had last year. The latest plots are in the FDC electronic logbook at:
 - We still have some mysterious behavior with the small-scale prototype
   response with wiggles in the X vs. Y distributions that need to be
   understood. Beni has gotten a larger data set on the small-scale
   prototype and the wiggles are still present. There seems to be a
   high-frequency wiggle and a low frequency wiggle. See the FDC logbook
   for plots.
 - Beni has started a bench test plan for the full-scale prototype and
   is presently working on it after incorporating feedback. The current
   information is contained on the FDC wiki page under the heading 
   "FDC test cosmic ray test stand".

Work List

 - The FDC short-term work list has been posted on the FDC web site.  
   This is continually being updated and DSC welcomes any feedback or 
   comments from the group.

Minutes prepared by Daniel. Send any comments or corrections along.