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FDC Weekly Meeting

Date: March 20, 2008

Participants: Daniel, Simon, Bill, Fernando, Roger, Mark

Next Meeting: March 28, 2008 @ 9:30 a.m. (tentative)

Full-Scale Prototype

 - Cathode daughter board design is essentially done.  Roger will prepare
   the PR in the next day or so.  He has already received several quotes
   for these board.  The order will be for 5 boards.
 - Cathode ground board design drawings nearly done.  Roger still has
   to get a blessing from Chuck on the placement of this new board.  Once
   this is done, PR will be prepared.  Roger will order 5 boards.
 - Once Roger gets word from Chuck on the placement of the cathode ground
   board, he will be able to quickly finish the cathode board design
   drawings.  He is essentially ready to prepare the PR.  For the
   full-scale prototype, we will not worry about holes in the cathodes.
   They will not come with holes in them, and we will have to make the
   cut outs ourselves (perhaps using the laser cutting procedure that
   Bill has presented earlier).
 - The delivery of the wire frame circuit boards should arrive this week.
   As Kim is away on vacation, Roger is in charge of looking out for
   the order, inspecting the boards upon arrival, and passing the
   boards on to Greg Arnold for stuffing.  Kim has already prepared
   instructions and the components to be stuffed and Roger will give
   these to Greg.  The current plan is that the QA/stuffing/cleaning
   procedures document will be prepared during/after the stuffing
   procedure after all lessons are learned.
 - Some known delivery time lines: Wire frame boards by March 27, 50-pin
   connectors for wire frames this week, 50-pin connectors for preamp
   daughter boards by July, ERNI connectors by the end of May, HV
   capacitors by May 9.
 - Update on cathodes:
    > We found out during the week that Sheldahl will not be able to
      provide our cathode board material for the foreseeable future
      (1-mil Kapton with 2 microns Cu).  They did, however, indicate
      that we might be able to get 2-mil Kapton with 0.5 microns Cu.
      Roger is in contact with Sheldahl this week on final word on
      what they can provide.  Simon indicated that the 1-mil Kapton +
      2 microns Cu is similar in thickness to 2-mil Kapton + 0.5 micron
      Cu (basically a wash in terms of radiation lengths).  
    > Roger has been in contact with CCT Marketing (the board house).
      They are about to shut down.  However, they told Roger that if
      we can get them the board material by Apr. 14, they will be able
      to get our order in.
    > We decided to push ahead and order the board material and move
      on with the order.  Fernando indicated that he is not worried
      about the cathode board performance going to thinner Cu, he is
      more concerned about soldering/attaching the connectors.  We
      will need to come up with a final procedure for this operation,
      and presumably we can finalize this procedure on the boards for
      the full-scale prototype.
    > We also decided to try to order cathode boards of the 2-mil Kapton
      + 0.5 micron Cu for our small-scale prototype for checkout.  It
      was felt that we could test these boards electrically much faster
      this way.  The question is whether CCT can handle this order, but
      we will try.
    > Roger is now starting the dialog with Sheldahl and CCT Marketing
      regarding handling and flatness specifications based on the
      document that DSC prepared.  Word to come soon on what can be
      achieved.   It was felt that even if the boards are not any
      better in quality that the boards that we have for the small-scale
      prototype, we would still move ahead with the order.
    > As Brian was not at the meeting, we have not heard whether he has
      received word from Jack Segal on our move-in date from the EEL
      building clean room.  DSC has requested the information from Brian
      and we will know soon.
  - No progress has occurred on modifying the aluminum construction
    jig due to other commitments.

Test Frame Wire Winding

 - As the Phase 1 wire winding contract has been signed, IUCF is now
   working on getting ready for the test winds.  They have indicated
   that the wire winding machine is fully functional and ready.  They
   are working on setting up the tension measurement system and the
   wire measurement system.  They would like to have everything working
   at some level before Brian heads out there.
 - For the wire winding, tension measurements, and position measurements,
   IUCF is working on developing (and then constructing) jigs to
   support the frame flat.  DSC is working to get IUCF the information
   that they need (drawing packages) so that they can move forward.
 - After the meeting, DSC asked the IUCF folks if they would prefer that
   we send them a wire frame and a strongback.  They indicated that this
   would be very helpful.  Brian is working now to set up the shipment
   to get it there as soon as possible.
 - It is still not fully clear when they will want Brian to arrive.
   Hopefully we can converge soon on getting IUCF the information they
   need.  Their manpower is now available for this work and we must work
   to get them what they need to proceed.
 - IUCF has received the epoxy sample that we sent them.
 - DSC is working with Steve Christo to prepare a wire specification
   document for the tungsten and CuBe wires leading up to procurement.
   Steve is preparing a document for the Hall B chambers and we will
   most likely adopt this document for Hall D.

Wire Deadening Studies

 - Brian worked with Tom Elliott to complete a test of electroplating on
   one of our old small-scale prototype wire planes.  They prepared a 
   weak copper sulfate solution in an 8-cm diameter dish and submerged
   the wires into the solution.  They had already connected some externals
   lines to the traces on the PC board and completed the circuit by
   submerging a Cu disk in the copper sulfate solution.  Anyway, they came
   up with appropriate voltage settings and plating times and came up with
   a very good first attempt.  The finished plating region was reasonably
   well defined (Brian still will look under a microscope at the edges), but
   there were a number of hard Cu whiskers that were formed.  Tom has a
   procedure in place already to eliminate these.  The process is to periodically
   reverse the voltage on the circuit.  In one setting the copper in the solution
   plates on the wire and in the other setting the wire is electropolished.
   A photo is included in the FDC TDR under the wire stringing section.

Stack Assembly Procedures

 - Tim and Bill have worked to consider our stack assembly procedures
   in more detail based on practical considerations.  They have
   prepared a document that we discussed briefly.  There were some
   apparent inaccuracies in the procedures and we will work to
   finalize this document.

Composite Cathode Updates

 - No progress on completing the composite cathode cathode sandwich
   as Brian had other things to work on this week.  This prototype
   will be worked on to finalize the Rohacell sealing procedure, the
   ground plane attachment procedure (including connections to the
   outside), and attachment of the gas ports.

Grounding Issues

 - Fernando will supply an overall grounding specification document 
   very soon.  He is working on it.

Gas Volume Definition

 - Bill reported that Dave Meekins has been having problems getting
   the flow calculations done due to the specifics of our large size
   but narrow gas volumes.  Bill is working with Dave to make gas
   volumes of varying geometries in an attempt to get around the
   problems encountered.  As preliminary answers come out of the
   calculations, we will go over them and discuss them so that we
   can make a design decision as to where to put the holes in the
   cathode boards.

STB/HVTB Discussion

 - Kim needs to provide the appropriate CAD files to Bill/Chuck of her
   board design drawings for inclusion in the model.
 - Kim has passed onto Brian the details for the needed modifications to
   the aluminum tooling plate jig for wire frame construction.  This
   work is needed for the jig plate to clear the pre-stuffed components
   on the circuit boards.  The work will be completed within the next
   several weeks.

Cathode Board Discussion

 - 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.
 - Roger was planning to do some test soldering for the rigid flex
   cables to a sample cathode board.  No update was given during the

Small-Scale Prototype

 - Bill Gunning has completed the soldering of the connectors to the
   new small-scale prototype cathode boards (+/-75 deg, 2 micron Cu)
   and Simon has gotten them.  Simon will clean the boards and then
   install them into the prototype.  The hope is get a cosmic run
   started over the weekend.  Hopefully early next week we will have
   some results regarding basic electrical properties, signal to
   noise levels, and resolution.  We would like to be able to have
   something to say regarding the 2 micron Cu performance for the
   review next week.  In order to make this work and get results that
   are comparable to earlier results, Simon will reinstall the
   SIP amplifiers and the charge integrating ADCs.
 - At the current time, Simon is making progress on getting the
   acquisition up and running again and he is quite close.

Cathode Flatness Measurements

 - We decided to push ahead on the cathode flatness measurement.  We
   are working on the followings:
   > Brian will prepare two samples of a cathode board mounted on
     a frame to send to the Brown and Sharp folks as well as to the
     company with the measurement system.  There are concerns (raised
     by the Brown and Sharp folks) that the laser triangulation system
     might not work on our boards due to high surface reflectivity.
     It is not clear if we send them samples whether they will look
     at them.  Bill will continue to act as the interface on these
   > We will most likely push ahead an order the $1.4k system for
     use on the horizontal milling machine and CMM here at JLab.

Upcoming Reviews

  - The combined tracking/PID review for Hall D is scheduled to take
    place on March 27 and 28.  We are presently working on the TDR
    and the talks.  Complete details are given on the Hall D web site 
  - In preparation for the meeting, we will need an updated set of
    design drawings for the FDC web site.  New drawings from the
    mechanical model will need to be provided that reflect the current


 - DSC has collected all of the available FDC subsystem design drawings
   and placed them on the FDC website.  The URL is:
   http://www.jlab.org/Hall-D/detector/fdc/drawings.html.  Folks should
   go through the drawings and let DSC know what drawings and/or categories
   are missing for a complete design set.
 - Also folks should send DSC the latest design drawings where there
   have been changes to keep this web site up-to-date through the
   review season.

Work List

 - The FDC short-term work list has been posted on the FDC web site
   (see http://www.jlab.org/Hall-D/detector/fdc/).  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.