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FDC Weekly Meeting

Date: September 11, 2008

Participants: Daniel, Simon, Fernando, Mark S., Kim, Eugene, Bill, Micah, Herun, Jim, Beni, Elke

Next Meeting: September 25, 2008 @ 1:30 p.m.


 - Simon will be giving the FDC report at the collaboration meeting next
   week.  He will circulate his slides shortly for feedback.
 - The FDC DOE report is due by the end of this month.  The report will
   be on the prototype wire winding from Phase 1.  Elke will provide DSC
   with an exact title and a template document in something called "word"?
   DSC is suspicious that Elke was speaking in German and really meant
   LaTeX.  DSC will work to complete the report in the next week or so
   and circulate it for feedback.

Full-Scale Prototype Updates

 - Clean Room:
    * Brian is working to put our clean room/tent together.  He has gathered
      sticky mats, gowns, hats, gloves, shoe covers, cleaning equipment, 
      trash cans, etc..  He has ordered a few things such as sticky rollers 
      to clean the area that will arrive soon.  He will get a bench and a 
      storage closet soon.  
    * Brian and I are now finalizing a procedure for entering into and 
      leaving the clean space that we will all have to follow.  After this 
      procedure is finalized, we will all meet at the clean tent have a 
      walkthrough of everything.  As of now, we will be following full clean 
      room procedures in the tent.
    * The clean tent power and clean tent itself have been loaned for
      use to Jack Segal and the HD-Ice folks for the next week while we
      wait for our cathodes to show up.
 - Procurements:
    * Roger has not finished the design work for the cathode rigid-flex 
      assemblies.  As he is away for the rest of the month and Kim isn't
      fully comfortable finishing the design, we have decided to put things
      on hold until Roger returns.  The final number of these boards (roughly 
      70) has yet to be finalized.
    * Elke asked us to prepare a spreadsheet listing all expenditures for the
      full-scale prototype.  Kim has started to prepare this including all
      of her procurements (including those through Fernando) and those of
      Bill.  She still needs input from Brian, Roger, Lorelei, Simon, and
      anyone else who has order parts n' pieces.  We will post a draft of
      this spreadsheet in an accessible place shortly.
    * Brian is working on the procurement of the sense and field wires
      for the full-scale prototype.  DSC has prepared two documents for our 
      wires: Wire Specifications Document and Wire Testing Document.  
      These documents have been passed on to the wire suppliers.  More 
      discussion on this when Brian returns.  These documents are posted on 
      the FDC procedures web page.
 - Fernando has considered how we will make the connections from the HVTBs 
   to the power supplies.  He has identified a connector that will connect 
   to the baby cables soldered to the HVTB and the cables that go to the 
   power supply.  Bill is working to put the connectors into the 3D CAD
   model and to detail how they will be attached (as they are quite massive).
   Once we get some of these details worked out, we will discuss when we
   want to place the order.
 - Brian identified a group that can do our SEM wire studies (the W&M group).
   Brian brought them our already prepared sample from our earlier SEM tests 
   to see if they were content with our slide.  They were not and redid the
   slide and then performed some scans.  Eugene showed a sample of SEM
   pictures that showed the wires were quite dirty (likely dust particles).  
   However, one picture showed a wire sliver coming off the sample.  We have
   no idea what this was. The picture that Eugene showed have been placed on
   the FDC web page in the SEM directory.  Note that our new SEM contact can 
   be used to study a sample of the cathode board that we received from Allflex.
   Fernando has prepared the sample and given it to DSC.  This will be done
   when Brian returns.

Cathode Planning

 - We have not gotten any updates on the shipment of our cathode board
   order.  We are expecting it any day now.  Kim will check with Allflex
   to find out when the package was or will be shipped.
 - We have not yet devised methods for handling the boards when they
   arrive from Allflex.  This will have to be developed once the boards
   arrive.  Presently we are planning on doing a battery of QA checks on
   all boards in the first order.
 - Bill has not done any more work on the system to cut the cathode edges.
   More to come when he gets back to this.
 - Holes, holes, holes:
     * We are still pondering deeply whether we will include the central
       Kapton beam hole in the cathode boards and whether we will include
       the side gas holes.  Bill is convinced that the perimeter gas holes
       in the frame are sufficient.
     * Eugene's preliminary FCAL rate studies show only a modest improvement
       if the Kapton in the central beam region is removed (of course in
       all scenarios there is no Cu in the beam area).  These calculations
       are being followed up by Sasha.
     * Bill and Mark want to do some test hole cuts (with a punch) in one of
       our cathode prototypes.  Bill has a small size punch and a large size
       punch will be coming with the cathode order.  Eugene and Micah will
       measure the cathode tension for the prototype that they will use
       before the cuts are made. This tension measurement will use the weight 
       deflection method already used by Eugene.
     * The nominal plan as of now is to set the cathode tension on the
       boards and then to add the central hole.
 - Please consult regularly the cathode R&D plan to better understand the 
   order and the time assignments.  Contact DSC with questions.
 - Cathode flatness measuring system:
     * All order parts n' pieces have arrived.  The machined parts from FSU
       have been shipped but not received.  Bill will check into this.
     * Mark has prepared the stabilizers for the granite table and has
       attached the pieces for the rail installation.
     * The granite table has been moved into EEL 126.
     * As soon as the parts from FSU arrive, Bill and Mark will install
       the rails and then turn things over to Micah who is standing by to 
       install/attach his parts n' pieces to the system.
     * Micah stated that the scanning and display software will be ready
       to go when the system is put together.  He is mostly done with his
       planned work.
 - Eugene has posted GlueX-doc-1090 containing all details regarding his
   studies on the cathode tension measurements and the allowed flatness
   variations.  He believes that if we can keep the flatness within 200 
   microns, we will be in good shape.
 - Brian and Bill should begin to layout a detailed outline for the cathode
   construction steps and circulate for feedback.

Wire Frame Construction

 - The frame that was used for our wire tension load test (which is 
   discussed in the FDC TDR) has been modified to include the pockets for the 
   rigid-flex assembly and the bolt holes.  It was machined to the 
   nominal I.D. and O.D. of our wire frames.  The foam core and the G10 
   skin were removed to an I.D. of 1032 mm to account for the problem 
   with the HV decoupling capacitor placement.  The plan is to redo our 
   loading tests and measure the in-plane and out-of-plane distortions of the
   wire frame up to a load of 50 lbs max (the full wire load is about
   35 lbs).  Bill is working on the FEA calculations to determine the
   loading limits for the frame.  This will also tell us how high in tension
   we can go with our load test, which uses a single wire down the middle
   of the frame (which is significantly worse that the distributed load of
   the real frame).
 - The nominal wire frame construction plan devised by Brian will be
   updated by Bill before the start of wire frame construction.  The
   current version of the plan is posted on the FDC web page under the 
   procedures link.  It will be updated when Bill is done working his magic.
 - Bill will look into performing the PCB through hole enlargement next
   week.  We need to make sure that the boards are handled properly and that
   the drilling out of the holes is properly done.  The boards will then
   all need to be properly cleaned.
 - We are presently planning on borrowing an A-frame for EEL 126 for the
   wire frame construction (that Tim arranged).  No other frames could
   be found in storage that we could claim.
 - PCB updates:
     * Kim has nearly finished the moving of the decoupling capacitors on 
       the back side of the STBs. Fernando is now looking over the design 
       drawings to make sure all is well.  
     * A couple of changes have been decided upon by Fernando.  One is that
       the protection resistors on the STBs that were chosen to be 10k will
       be changed to 1M.  Fernando is working to decide if this change needs
       to be made on the boards for the full-scale prototype.  Second is
       the HVTB resistors will be changed from an 805 package to a 1206
       package to give an increased current rating.
     * The updated PCB drawings will be given over to Bill so that they
       can be put into the 3D model.
     * The PCBs for the FDC will need to be handled by all folks involved 
       with more care.  Many of the boards have sustained damage to the 
       fragile lap ends.  The damage is not severe enough to cause any 
       construction worries, but handling procedures do need to be 
       established and followed.

Test Frame Wire Winding

 - IUCF has supplied the official report from the Phase 1 wire winding
   continuation and an official budget for Phase 2.  Now that Elke is
   back, DSC will meet with her to go over things and we will discuss
   the situation (past, present, and future) in detail.  The current idea
   is that we will have a teleconference with IUCF in the first part of
   next week.

Spacer Design

 - Bill has not yet finalized a choice of material.  It looks like the
   best choice may be polypropylene.  He would prefer nylon-6 due to its
   superior mechanical properties, but nylon-6 absorbs water like a 
   sponge.  One problem with polypropylene is that it is very difficult
   to epoxy to it.  If this ring has o-rings on both sides, there is no
   problem here, but Bill needs to be able to attach the gas inlet and
   outlet tubings.  He described a number of potential work arounds.
 - We will be working to make a mechanical prototype as soon as the
   design is finalized.

Stack Assembly Procedures

 - DSC, Brian, Tim, 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 use 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.

Gas System Design

 - Slava is working on a preliminary layout of the gas handling system 
   for the CDC and FDC.  He provided two options for the FDC system design 
   that were essentially a basic version and a fancier version.  Slava's 
   design work was based on the original concept that Brian came up with 
   long ago.  Slava provided some drawings that DSC will review.  We will 
   then continue the design work as we have time.


 - 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.
 - Kim has provided a draft of a procedures document for the Phase 1 and
   Phase 2 wire frame PCB component attachment. She has merged this
   document with Fernando's cleaning and handling document.  The document
   is being finalized with some additional language on soldering iron
   temperature vs. time profiles.

Small-Scale Prototype

 - Simon and Fernando are in the home stretch on completing the specification
   of the cathode and anode ASIC dynamic range.  All required measurements
   have been completed and work is ongoing to finalize the test results in 
   the document.  What we have so far is posted as GlueX-doc-1070.
 - We still have the lingering issue of the problematic x-y plots from the
   2-micron Cu cathodes.  Simon will revisit this problem by taking some
   new pulser calibration data to see if this makes the apparent problem
   go away.

CAD Model

 - We discussed a bit about making sure all relevant design features
   of the FDC are in the full CAD model.  Tim will have Slava work to
   put in the capacitors and resistors on the wire frame PCBs into the 

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.