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FDC Weekly Meeting

Date: October 9, 2008

Participants: Daniel, Simon, Brian, Mark I., Eugene, Bill, Micah, Herun, Elke, Kim, Tim, Fernando

Next Meeting: October 16, 2008 @ 1:30 p.m.

Full-Scale Prototype Updates

 - Design Decision:
    * We will be switching from 31HF to 110HF foam in all composite FDC
 - Procurements:
    * Roger has not finished the design work for the cathode rigid-flex 
      assemblies.  We should aim to complete this work by the end of Oct.
    * Elke asked us to prepare a spreadsheet listing all expenditures for the
      full-scale prototype.  Kim has prepared a draft of this, but she still
      needs input from Brian, Roger, Lorelei, Simon, and anyone else who has 
      ordered parts n' pieces.
    * Brian has completed the PRs for the sense and field wires for the 
      full-scale prototype.  Both have been signed by Elke. DSC prepared 
      two documents for our wires: Wire Specifications Document and 
      Wire Testing Document.  These documents have been passed on to the wire 
      suppliers.  Brian indicated that Little Falls had no problems with the 
      CuBe wire spec.  However, CFW did not like our heat treatment requirement.  
      Brian will check with Steve Christo to get some feedback on this requirement.  
    * Brian will be responsible for preparing the order for the G10 rings
      for the full-scale prototype.  We should be able to put this order
      together rather soon.  Brian is in contact with the company regarding
      the thickness specification.
    * Bill will be responsible for preparing the order for the 110 Rohacell
      foam for all FDC frames.  Note that whether we order 110IG (Industrial
      Grade) vs. 110HF (High Frequency) does not matter.  The choice should
      be on availability and cost.
 - Working Space:
    * We need to make sure our clean room work is done is the clean room
      and our non-clean work is done in EEL 126.  Let's try to utilize
      our space properly. 
    * A new shelving unit has been installed into EEL 126 that makes the
      space usage much more tidy and efficient.  This looks good.  All
      table tops in our space are now amazing exposed!
 - Storage: Kim has been amassing various and sundry FDC-related components in
   her area.  She will bring them over to Simon for storage in F117 when she
   gets a chance.  We are trying to find someone to create and maintain a
   database for the FDC components that have been ordered and are awaiting
 - Bill is working to put the local HV connectors selected by Fernando into 
   the 3D CAD model and to detail how they will be attached (as they are 
   quite massive).  Bill will get back to this work when he has a chance.

Wire Frame Construction

 - We have settled on a thickness tolerance for the wire frame of 8 mils to 
   match the thickness tolerance for the cathode frames.  Elke wants us to
   write this up.
 - Bill and Mark have prepared a laminate with 110HF with some reasonable
   success.  Bill has indicated that the flatness of the 110HF sheets varies
   from sheet to sheet, but that we should be able to select sheets flat to
   5 mils or better.  It seems that we should order the foam sheets with
   allowance for waste and pick out the best sheets for our use.  We should
   be able to meet the flatness requirement.  Bill is now in contact with
   the Rohacell folks as they are working to see what flatness tolerances
   that can deliver.
 - For the next Rohacell order for the wire frame, we will add allowance
   for the two epoxy layers and make the Rohacell a few mils thinner.
 - Note: A new design study has indicated that we do not need solid (one piece)
   Rohacell cores.  We can split these up into quarters.  This eliminates
   significant material waste and does not compromise the ring strength (so
   sayeth all engineers present at the meeting).
 - We decided to use the solder sample boards to finalize the PCB lamination
   procedures.  We will then laminate the PCB ring to one of our existing
   G10/foam laminates.  Photographs will be taken of each of the steps.
 - Fernando will look at the PCBs that came back from Greg Arnold's group
   to verify quality.  He will also have Herun redo the electrical QA on the
   boards before construction.
 - Bill will look over the aluminum jig plates to check the latest work
   by the machine shop to add the clearance holes.
 - The wooden shipping box will be shipped back to JLab by IUCF.  It looks
   like the paperwork has been completed.
 - PCB updates:
     * Kim has 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.  
     * 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.

Cathode Planning

 - Elke wants us to prepare a write-up for the cathode frame tolerance.
 - Mark got the nitrogen flowing through our cathode box using the dewar that
   Brian ordered.  Brian will check on the boards to be sure the environment
   inside the storage box is O.K..
 - The W&M SEM group did some study of a small piece of our sample cathode
   board from Allflex.  This sample was one that was stained with some sort of
   surface contamination.
   Their mass spectrometer analysis revealed only copper.  This is at odds
   with what Fernando found, which is that this contamination appears to be
   non-conducting.  Fernando has done some additional resistance measurements
   and the material has resistances of 10k to 100M.  This could be copper oxide.
   We want to close the loop on what the heck these are splotches are.
   Fernando will go and talk with the SEM folks to see if they can figure this
   out with us.
 - Roger will contact Allflex within the next week to follow up with the
   sales representative on when we plan to place the order for the remaining
   boards for the full-scale prototype.
 - Bill has not done any more work on the system to cut the cathode edges.
   More to come when he gets back to this.
 - Central cathode board hole:
     * We discussed more about the central hole in the cathodes.  This
       is not required for gas flow or pressure equalization.  Alex Somov
       has completed some new MC studies showing that the effect of the
       Kapton on the FCAL rates are at the 10% level.  So, apparently we
       do not need to include these holes.
 - Cathode flatness measuring system:
     * Micah is working to get the system operational.  He is very close.
       He will begin by measuring the surface flatness profile of the
       granite table.
 - Brian and Bill should begin to layout a detailed outline for the cathode
   construction steps and circulate for feedback.
 - DSC wants more parallel development.  Mark will focus mainly on the
   wire frame R&D and Brian will focus more on the cathode R&D.  However,
   in the short term, the wire frame development has top priority.

Full-Scale Prototype Wire Winding

 - The Phase 2 winding paperwork has now been signed by the 12 GeV folks and
   passed on to our contracts people.  The contract should be in place very
 - DSC has gotten final specifications on the Moire masks from IUCF and
   passed this onto Roger.  He has asked Roger to have this work completed
   in about 1 month.
 - It may be, given our current estimates of schedules, that we will not
   be ready to send the frames to IUCF before the end of November.  This
   schedule should come into crisper focus in a few weeks.  It all depends
   on when we can place the Rohacell and G10 orders and what the turn around
   time is.  We need 3 weeks to make the frames one all parts are in.

Spacer Design

 - We are presently focusing on two different choices for the material
   of the solid spacer.  One is polypropylene, and the other is Noryl.  Noryl
   is more expensive, but may have less handling and construction costs.  We
   need to do a price estimate.  We can easily laminate Noryl to the
   cathode board and eliminate one o-ring.  Polypropylene does not epoxy
   well and would need to undergo an acid etching step to better prepare the
   surface to receive the epoxy.  Bill will look into this more.
 - We will be working to make a mechanical prototype as soon as the
   design is finalized.

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 is doing some ANSYS model (with his new-found skills) to better
   study the connector that goes from the daughter board card to the
   cooling loop.  He will add these studies to Fernando's note.

Gas System Design

 - Slava has worked 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.  We will 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 have completed their studies of the dynamic range
   for the anode and cathode ASIC dynamic range.  The study results are
   posted as GlueX-doc-1070.  Simon and Fernando are now working with the 
   CDC folks to help them finish their studies.  No word yet on when they 
   will be done and ready for sending things off to Mitch.  Stay tuned.
 - 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.

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.