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FDC Weekly Meeting

Date: February 12, 2009

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

Next Meeting: February 19, 2009 @ 1:30 p.m.

Full-Scale Prototype Updates

 - Procurements:
    * We want the remainder of the cathode order to go out by the end of this
      month. This sets the time frame for the redesign work Roger is doing.
      The plan is nominally to order 6 more full sets of 2 micron boards and
      2 full sets of 5 micron boards. If there is money available, it would
      not be bad to order a couple more sets of 2 micron boards as we will need
      several for R&D work.
 - Chamber Wire:
    * Brian has provided samples of our sense and field wires to the SEM folks,
      they will complete the mass spectroscopy analysis. As we have not heard
      anything for a while, Brian will check in with them. 
    * 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, 
 - DSC has talked to the Hall A representative Bogdan Wojtsekhowski about sharing
   the clean tent. We gave them use of the tent this week and will take control
   back early next week. Hopefully the group will be done with their work during
   this period.
 - A bottle neck in our prototype construction is that we have only one cathode
   board tranfer ring. Bill will prepare a drawing for the shop and work to have
   a second frame constructed.

Wire Frame Construction

 - IUCF is now working on a technique to check the relative positions of the
   sense and field wires on the winding table to eliminate the systematic
   40 micron offset that we saw last time. They should be sending around some
   preliminary measurement data this week and we will set up a phone meeting
   to talk about progress and schedule in the next couple of business days.
 - Nominally Bill will go to IUCF for the week of March 16. If this moves
   up, IUCF will give us a heads up so plans can be made.
 - To remove the problem with glue wicking up through the vias in the PC boards,
   we have asked Kim to reduce the size of the vias (to eliminate the openings)
   and to cover the vias with the solder mask material. This amounts to a belt
   and suspenders approach.
 - Bill has designed a wire frame protective cover that will be in place during
   the Phase 2 component stuffing. This cover is in the shop now being machined
   and will be done shortly. We may also design a turntable for the solder
   technicians to use with the wire frame for this task.
 - 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.

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
 - We spent some time reviewing the basic cathode design and where the nominal
   tension number of 500 N/m came from. Whether the final value ultimately
   is lower or higher remains to be seen. It depends on the half gap, the
   quality of the cathode boards, and the glue seams.
 - Progress updates:
     * The cathode edge cutting system continues to be tested. The system seems 
       to work well. Bill and Mark have made some test cuts with our dummy
       cathode boards and are looking at them with a camera mounted to a mill
       in the JLab machine shop. The edge looks well defined to the level of
       +/- 3 mils. Work continues to improve the cathode positioning procedure
       relative to the cutting blade. We are trying to rig up a camera to allow 
       us to easily view the position of the cutting head relative to the edge of 
       the strip along the full length of the board. A few small pieces are in the 
       machine shop and should be in our possession shortly. Hopefully we will be 
       far enough along to test cut one set of the 5 micron "real" boards next week.
     * No progress on completing the cathode construction document. Stay
     * We are working to prepare three G10/foam laminates for prototype cathode
       cathode boards. The first is now out of the machine shop and had the
       second G10 annulus laminated on. There was a problem with the jig plate
       used for the vacuum bagging that added a distortion to the frame. It should
       still be perfectly useable for the mechanical tests. A new base for the
       cathode vacuum bagging procedure has been prepared in the shop and will be
       used for our next frame. The first frame is now being machined to include
       the gas through-holes. This frame should therefore be as realistic as
     * Today the Kapton cathode membrane that is in the tensioning fixture set to
       500 N/m will be attached to the frame. This procedure will use weights placed
       on top of the frame to apply pressure. Ultimately Bill would like to use
       pressure applied by one or two air bladders. As we do not want to wait to
       proceed, we will likely go the air bladder route if the frames survive the
       mechanical loads. Tomorrow we will see if the frame handles the tension load 
       of the membrane and measure the in-plane and out-of-plane distortions.
       We will make up a second frame on Monday or Tuesday of next week. The
       associated Kapton cathode membrane for this frame is already put together
       and rolled up for storage. Brian used the cathode edge cutter to make
       a three piece panel for the second frame.
     * Roger has completed modifications for one of the three cathode panels
       to allow for stretching perpendicular to the strips of up to 4 or 5 mm
       and parallel to the strips of 2 to 3 mm. He sees no problems modifying
       the other two boards. We need to get a progress update on this work as
       Roger was not present today. We want the remainder of the cathode order 
       to go out by the end of this month.
     * We discussed plans for using an optical system to measure the
       cathode board distortions after they have been tensioned. Presumably
       we could use the horizontal mill in the machine shop using their
       camera system. This will most likely be needed in about 6 weeks.
     * The clearance issue that Bill raised at our last meeting between the
       cathode daughter boards between neighboring layers in the middle of the
       cathode sandwich can be solved by flipping the artwork on the cathode
       daughter board cards. Bill has verified this will work for all clearance
       issues. Roger will go ahead and make the necessary changes.
     * Brian has tried to find a roll of 12.7 micron aluminized mylar for our
       ground plane material but is not having luck so far. All we have on hand at 
       present is 6.3 micron material and we will use this in the mechanical
       cathode sandwich prototype.
     * We will need to place an order soon for more G10 annuli for the cathode
       frames (the larger pieces). Bill will put together a PR shortly after
       Mark checks our inventory. This is confusing as we should have ordered
       all of the necessary G10 stock with our last order in December.
 - We discussed how we want to store the cathode frames after they are made. The
   consensus was that they should like be stored locked into a flat position. We
   should avoid unnessary flexing of the frames from the flat to distorted positions.

Cathode flatness measuring system

 - Documentation of the system continues. See the FDC wiki page for details.
 - Brian has completed a PR for a second laser for the FDC work.

Spacer Design

 - The spacer frames are now under construction in the JLab machine shop. They
   should be in our possession very shortly.

Stack Assembly Procedures

 - DSC, Brian, and 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.


 - 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
 - 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.