Minutes-2-26-2009

FDC Weekly Meeting

Date: February 26, 2009

Participants: Daniel, Brian, Bill, Roger, Beni, Mark I., Eugene, Fernando, Simon

Next Meeting: March 5, 2009 @ 1:30 p.m.

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Full-Scale Prototype Updates

 - Clean Room Issues:
    * The Hall A folks completed their second stint in our clean tent.
      They still need probably another week and we will need to figure
      out when that can happen.
 - Cathode Board Redesign:
    * Roger is continuing work on the cathode board redesign to allow for the
      board stretching. So far he has completed work on the two end boards.
      They should each have at least 5 mm of clearance around all holes.
      Roger will complete work on the center board panel, which he believes
      should actually be the easiest of the three to complete. We are trying
      to have the order ready to go out in just over two weeks. We talked
      about board shipping and decided it is O.K. to roll the boards up
      and seal them and ship them in a metal tube container.
    * Roger has a new version of the cathode daughter board with the power
      connector flipped to the other side. Drawings have been circulated
      to Fernando and Bill for study. The order for these boards will go
      out after we study the completed cathode sandwich prototype.
 - Chamber Wire:
    * Brian talked to the SEM folks and they will complete their tests when
      the new SEM is configured in the next few weeks.  Brian will prepare
      a final QA report with photos and test results for all wires when all 
      studies are complete.
 - Mark S. is also responsible for upkeep of the list of procurements for
   the full-scale prototypes.
      * Location: M Drive/halld/Electronics, or for more sophisticated folks, 
        /u/group/halld/Electronics.
 - A bottle neck in our prototype construction is that we have only one 
   cathode board tranfer ring. A second transfer ring should be ready in
   the shop this week.
 - Procurements:
     * Fernando completed a PR for two HV modules, HV cable, and connectors
       for the prototype tests. We are awaiting signatures.

Wire Frame Update

 - Status: IUCF has wound the table and positioned the first frame. The
   wires were glued in place this morning. The frame will be removed from
   the winding table tomorrow and then the wire positions will be measured.
   On Monday the wire tensions will be measured.  Keith noted that the
   first wire frame was problematic as the frame was not particularly
   flat. All frames met our flatness spec of 5 mils, so DSC will talk more
   with Keith about this shortly.  The wires will be attached to the second 
   frame after the data analysis is complete on the first frame.  Note that
   IUCF is winding the four planes in the order of worst to best.
 - Nominally Bill will go to IUCF for the week of March 16. This will
   definitely not be moved earlier.
 - PCB problems:
     * There were several places on the HTVBs where +HV bus vias were 
       positioned under the field wires and were left as bare copper. Also
       several places the design relied on solder mask to act as a 3 kV
       stand off. The boards need to be re-inspected to deal with these
       problems.
     * Fernando is maintaining a problem/redesign work list for the wire
       frame circuit boards. He will update the list with the latest
       issues.
 - Bill has designed a wire frame protective cover that will be in place 
   during the Phase 2 component stuffing. It needs to be test fitted onto 
   our existing wire frame to be sure all is good in the world. Bill will 
   also design a turntable for the solder technicians to use with the wire 
   frame for this task.
 - Bill/Mark will update the wire frame construction document based on lessons
   learned from the prototype frames. A new version will be posted when his
   work is done.
 - We plan on performing the electroplating technique with at least a couple
   of our full-scale prototype wire planes. We will do some more practice on
   the Phase 1 winding planes to finalize the technique and to prepare a 
   procedures document. A positioning jig will be put together to allow for
   precision positioning of the deadened region and its size.  We will plan on
   doing optical scans of the plated region to be sure the plated region is
   very smooth and well defined.
 - To be compatible with the HV connectors that Fernando has selected, we 
   will likely have to modify the granularity of the HV connections on 
   the HVTBs. We will reduce the number of connections on each HVTB by a
   factor of 2. More thinking on the split remains to be done.

Cathode Construction

 - We reviewed the cathode R&D timeline. Folks are reminded to pass on
   progress updates to Chuck every Wednesday.  The current schedule is
   being kept on the mdrive at:
     * Location: M:\halld\Individual-Schedules\FDC or for more sophisticated 
       folks, /u/group/halld/Individual-Schedules/FDC
 - Progress updates:
     * Cathode sandwich prototype work: During the past week we have finally
       developed a system to allow for vacuum bagging of the cathode boards
       to the cathode frame. Our second dummy cathode frame for the mechanical
       cathode sandwich prototype is now ready. We will tension the ground
       plane early next week and assembly the cathode sandwich prototype.
       We should then be able to complete a battery of QA measurements to
       determine where our construction procedures need to be modified or
       improved.
     * Bill has started work on the cathode construction document. He will
       circulate a draft shortly with what he has for comments.  This will
       most likely occur after the completion of the cathode sandwich
       mechanical prototype.
     * Edge cutter update: Pieces for the camera have come back from the
       shop and the cutter is now ready for tests using this new system.
       We expect to be cutting real cathode boards by next week.
     * We will need to place an order for more G10 to complete the frames
       for the full-scale prototype. This will be prepared this week.
     * Bill and DSC will meet offline to discuss the R&D schedule for the
       cathodes. We need to decide what prototype we want to build next or
       if we just want to move to construct a "real" cathode frame and
       cathode sandwich.
     * To make the most efficient use of shop time, we will likely prepare
       4 cathode frames and have them machined.
     * We discussed the ground connections to the cathode ground pours. We
       will test our nominal procedures on the mechanical prototype next
       week.
     * Bill surmised that we might be ready to start construction of a cathode
       frame prototype using our "real" 5 micron Cu boards by the end of next
       week.
     

Cathode flatness measuring system

 - Documentation of the system continues. See the FDC wiki page for details.

Spacer Design

 - The spacer frames are now under construction in the JLab machine shop. They
   should be in our possession very shortly. Mark will then install the
   Kapton gas tubes on the inlet and outlet.

Stack Assembly Procedures

 - We Bill will work to finalize the stack assembly construction document 
   that has been prepared.  This document should be in place before we get 
   too far in the construction process.
 - Bill has found some plastic threaded rods that could be used to 
   compress the stack.  We will be receiving some samples shortly and
   will carry out some loading tests.

Cooling System Tests

 - Fernando is in the process of writing up the results from his cooling 
   system studies.  Stay tuned for the GlueX note.
 - Bill has done some ANSYS modeling to better study the connector that 
   goes from the daughter board card to the cooling loop.  These will be
   added to Fernando's note.

Documentation

 - 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

 - We will be moving the FDC cosmic ray test stand from the Test Lab back
   to the EEL building. This move should be probably take place in April.
 - 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.
 - We would like to put together a bench test plan for the full-scale 
   prototype within the next couple of weeks. This preliminary test plan 
   will be used to provide information on what test stand fixtures to 
   support the chamber we will require. Bill can then work on the design 
   and get things prepared in the shop.  Also, we would like to layout a 
   design for the electronics before too much longer so that we can reduce 
   time from when the full-scale prototype is constructed to when we get 
   into the test plan.

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.