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FDC Weekly Meeting

Date: October 22, 2009

Participants: Daniel, Beni, Bill, Simon, Fernando, Mark S., Mark I., Casey, Eugene, Glenn

Next Meeting: October 29, 2009 @ 10:00 a.m.


 - Next week the technicians will be at crane training at the end of the
   week. Hopefully the physicists will be busy going through the test plan 
   for studying the single layer prototype detector.
 - Next week's meeting time will be at 10:00 a.m. due to schedule conflicts
   with interviews.

General Construction Updates

 - Tom Carstens and crew completed the reassembly of the clean tent in
   EEL 126 and we have reorganized the room a bit. Lots of activity and
   progress occurred very quickly. The space is now being fully utilized
   for construction of the full-scale prototype. With the clean tent
   running for several days, a device to measure the cleanliness of the
   tent recorded particle counts of less than 1000 per cubic foot (of size
   greater than 0.5 microns). Looking at the floor, you wouldn't have
   guessed this.
 - Stack assembly for the single-layer prototype is in progress. The wire
   frame P1 has been laminated to its associated cathode/gas window frame
   and placed onto the stack assembly jig. We have to attach the HV pigtails
   for P1 and then install the gas spacer ring and the second cathode/gas
   window frame. We will be working on leak checking using an argon-sensitive 
   gas sniffer using an argon/CO2 gas mixture inside the prototype. This
   work should begin tomorrow. All rigid-flex assemblies have been included 
   on the two single cathodes that include the gas windows, and associated
   electrical QA has been completed.
 - We are finalizing the grounding configuration for the single-layer
   prototype. We will use two new preamplifier cards, four old preamplifier 
   cards (used with the small-scale prototype), and some temporary grounding 
   cards that Fernando has prepared. Fernando will provide a list of signal, 
   HV, and grounding cables to Mark S. to be made over the next couple of
   days. Fernando's temporary ground boards will be ready by Wednesday of
   next week.
 - 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.

Wire Frame Update

 - Wire frame P1 has successfully passed all electrical QA checkout and
   its LV and preamp card connectors were fortified with epoxy. Frame
   P1 was laminated to its associated cathode frame (the screwed up cathode
   with the gas window).
 - Wire frame P4 has undergone a preliminary electrical QA check and has
   a few problems that need to be addressed.  Wire frame P3 will then follow.
 - 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.
 - Kim has verified that she will be available in December to complete the
   wire board redesign work.

Cathode Update

 - Progress updates:
     * All rigid-flex assemblies have gone through QA and been delivered
       for attachment to our cathodes.
     * We do not have enough rigid-flex assemblies due to yield losses on
       the original order of 60 (54 are needed for the prototype). An order
       for another 2 dozen pieces was supposed to go out last week but
       apparently did not. DSC will follow up with Roger after the meeting.
     * Rigid-flex soldering update: The two single cathodes are now fully
       populated with rigid-flex assemblies. Casey has completed work on
       another cathode that is part of a cathode sandwich. He is ready to
       flip the sandwich over and proceed on the other cathode.
 - The current draft of the cathode construction document is located at:
   /u/group/halld/Engineering/PRELIMINARY DOCUMENTS.
 - 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.
 - Roger has verified that he will be available in December to complete the
   cathode board redesign work.

ASIC Preamplifiers

 - Fernando has certified the lastest ASIC preamplifiers as meeting our
   design specifications. See GlueX-doc-1364 (The Gas-II/GPC-II GlueX
   Preamp Card Preliminary Test Results) for details and results. Fernando
   will make one anode board and one cathode board available for the single
   layer tests next week.

Design Discussion

 - Bill raised an intriguing idea for simplified the rigid-flex and cathode
   design. We agreed it might be something that will simplify the design,
   reduce costs, and make the soldering work easier. As there were some
   issue to hash out, we decided to take this offline and continue the
   discussions. The basic idea Bill had was to fold the cathode board
   through the slot on the frame and to solder the flex assembly to it on
   the back side. This would eliminate cutting pockets into the back of the
   wire frame and allow us to increase the trace spacing on the cathode for
   soldering to the rigid-flex assembly. More to come.

Cosmic Ray Test Stand

 - Beni has been investigating the wiggles seen in the reconstructed wire
   position from the cathodes. We focussed on log entry 419 in the
   FDC logbook. We believe that the periodicity seen is due to the algorithm
   Beni is using to determine the U and V centroids. He will talk to Simon
   and get his parametric form to see if this addresses the problems.

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.