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FDC Weekly Meeting

Date: April 16, 2009

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

Next Meeting: April 23, 2009 @ 1:30 p.m.

Full-Scale Prototype Updates

 - Cathode Board Orders
    * Cathode boards: The order is out the door. Roger has worked to 
      clarify a few things with the Allflex folks. We are now expecting
      delivery by the beginning to middle of May. We will get a firmer
      date soon. Mark S. will send the transport box up to Allflex.
      Roger still has to send up a note on packing and shipping instructions.
      This will happen soon. The issue of board corrosions and steps to
      mitigate this further are being considered at the company. They
      will update Roger shortly.
    * Cathode daughter boards: Roger is getting quotes now in preparation
      for getting the PR signed. Not much longer until this goes out.
      Expected turn around time is 2 weeks.
 - Chamber Wire:
    * Brian announced that the SEM studies of our wires should be complete
      in about a week. This includes a check of the ovality of our sense
      wire and the mass spectroscopy reports. Stay tuned.  Brian will 
      prepare a final QA report with photos and test results for all wires 
      when all studies are complete.
 - Soldering Work: Greg Arnold's group will not be available for our work
   until maybe the end of May. DSC talked to Fernando about having a backup
   if necessary to avoid delays in the prototype completion. It looks like
   we can get manpower if needed through Chris Cuevas' group so that delays
   on the wire board Phase 2 soldering and the connection of the rigid-flex
   assemblies to the cathodes is not delayed.  We may need to borrow the
   wave solder machine from Greg's group. More to come as schedules come
   into focus.
 - We will be sharing the clean tent with Hall B starting next week. Mark S.
   and Brian will clear the necessary space for our new roommates.
 - Bill received an estimate to make up 22 new cooling system clamps. The
   price is about $100 apiece. He will talk to Eugene for approval.
 - As the Fluourinert cooling charges the copper tubing, we will want to
   have these grounded. We discussed a plan for this and Fernando was in
   agreement that this should be O.K..
 - We reviewed remaining tasks to complete the design of the FDC design.
   DSC showed a preliminary list (see FDC design task list). This needs 
   to be looked over and fleshed out by folks.

Wire Frame Update

 - Status: The linear transducer has finally been sent off for refurbishment
   It should be back and reinstalled in about 1 week. No other news from
 - Bill will send Keith some information on which sections of the wire
   winding procedures document needs input from them to filling in holes.
   The start of this procedures document is included in Bill's IUCF trip 
   report (GlueX-doc-1229).
 - Bill has been updating the wire frame construction document based on 
   lessons learned from the prototype frames. He is working to incorporate
   some more relevant photographs. The newest version is located at
   /u/group/halld/Engineering/PRELIMINARY DOCUMENTS. Please read it over and
   give him feedback.
 - Brian will gather all the bits n' pieces for a write-up on the wire
   electroplating and post his document on the mdrive for feedback.
 - Bill is now designing the jig for the wire electroplating operation
   and it will be ready for submission to the shop at some point in the
   future. This is not a high-priority job at the moment.
 - The bearing for the rotatable platter for the Phase 2 soldering is in
   hand. Bill will complete the design and get the drawings to the shop
 - Mark will test fit the wire frame protective cover to be sure it is
   idiot-proof and does the required job.

Cathode Construction

 - We reviewed the cathode R&D timeline.  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:
     * The laminations of the Rohacell and the large G10 annuli for the
       cathode frames will be done by tomorrow and delivered to the
       machine shop (8 frames). An opening in the schedule has appeared and 
       this will machine these pieces starting on Monday.
     * Other JLab machine shop work: The aluminum clamp ring for the 
       tensioning facility will have its I.D. increased to give better
       access; One of the G10 tensioning rings will have its I.D. increased
       and will get a skim cut to remove old glue and Kapton; the thin G10
       rings that make up the remainder of the cathode frame laminates will
       have all the through-holes and gas holes added. This work should be
       completed in less than 2 weeks.
     * To deal with issues of epoxy seepage through our Kapton tape, we have
       done a test of a modified procedure where we first put removable tape
       on the copper side of the boards. After applying the Kapton tape to
       the back of the boards and allowing for it to cure, the tape on the
       front side is removed. This worked very well and we will do one more
       test with some dummy boards before laying up the last 2 micron Cu
       board set. For this work, we cannot float the boards in alcohol as it
       desolves the glue on the removable tape. Water has been shown to work
       as a reasonable alternative.
     * Due to work on other things, the attachment of the rigid-flex
       assemblies to the cathode sandwich mechanical prototype has not
       been completed yet. We will get back to this after the cathode frames
       are sent off to the machine shop. We will also include a spacer ring
       and wire frame to the mini-stack and add the cooling lines to get a
       more complete picture of the layout. Results soon.
     * Bill has been working on the cathode construction document. He will
       circulate a draft shortly.

Cathode Flatness Measuring System

 - Documentation of the system continues. See the FDC wiki page for details.
 - In order to make decisions on the tension settings for the cathode planes,
   we want to understand the surface flatness. We will want to scan our
   5 micron Cu cathode and then to scan our 2 micron Cu cathode once we have
   a frame to mount it to.  This is important input on the minimum tension

Stack Assembly Procedures

 - 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. Beni is working on designing the room layout in
   EEL 126. We will be working to remove the big storage shelf system to
   clear up space and try to get this out of the room in the next 2 to 3 
 - 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 decided to have a separate meeting to discuss what work
   we would like to do on the small-scale prototype.
 - Beni has started a bench test plan for the full-scale prototype and
   we discussed his preliminary document briefly. He will circulate it
   for feedback and we will continue to flesh it out.
 - For the full-scale prototype tests, we will have roughly 30 preamp
   boards stuffed (to be shared among everyone), 3 125 MHz FADCs, and
   "plenty" of TDCs. We need to flesh out a plan for who gets what and
   when. Beni is starting to work on this.
 - We discussed the thoughts regarding a beam test for the full-scale
   prototype. It looks like there may not be enough time and readout,
   but no final decision has been made. For now, we are pursuing what
   we can learn with cosmics and sources.

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.