Minutes 4-25-2007

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FDC Weekly Meeting

Date: April 25, 2007

Participants: Daniel, Simon, Tim, Kim, Roger, Chuck

Next Meeting: Wednesday, May 2, 2007 @ 1:30 p.m.

Design Drawings

 - Work continues to gather drawings for the FDC system from various
   folks.  DSC will pass these on to Elke when everything is gathered

Cathode Prototyping

 - Brian was away this week, so there was not much progress on work
   for the cathode boards and their measurements.
 - DSC wants to begin pursuing plans for some sort of cathode backing.
   This discussion will heat up over the next month or so.  The plan
   is to try various options this summer.
 - Gerard reported that he could not complete measurements of the
   strip-to-strip capacitance on one of the dummy flex boards that
   he has.  He found that the resistance between strips is only on
   the order of a few Ohms.  Simon verified this with another of the
   boards.  After some cleaning/scrubbing with acetone, the resistance
   went up to a few hundred Ohms.  We need to contact the board
   manufacturer to find out why these boards are problematic.
   Note: for the final production boards (and those for the prototype)
         we will spec that the boards should be tested electrically
         to meet our specs.
 - We discussed how to attach the cathode connectors to the circuit
   board.  The plan is to include a cutout in the cathode backing
   frame to allow a flex-style connect to fit in.  This will be soldered
   to the cathode board and to the connector.  Roger will begin to
   lay this out to ensure that we do not have any issues with space
 - We should plan on a two-piece board for the cathodes.

Circuit Boards

 - DSC wants to push ahead on a more serious design attempt on the
   HVTBs and STBs.  We discussed what decisions we need to make to
   allow Kim to move ahead.  We should plan on a two-piece design
   for the STBs and HVTBs to give us the needed flexibility for the
   HV segmentation.
 - We are close now in terms of making decisions that will allow these
   designs to move ahead.  We need them in the next few months so that
   we can complete the boards to get the wire frames to FNAL for
   winding this summer.
 - DSC would like to construct a circuit board from HVPF for the
   small-scale prototype for testing purposes.  We would like to
   get Fernando's input and opinions and then proceed.

FDC CD-2 Document

 - Work continues on preparing a short write-up detailing answers
   to the recommendations brought up during the DC review in March.
   Simon has prepared a first draft.  We are awaiting results from
   MC for the cathode and wire rates, the momentum and angle resolution,
   and the effect of the annulus material on photon conversions.

Magnetic Field Tests

 - We are pursuing a field test with our small-scale prototype in
   Hall B using the old pair spectrometer magnet.  DSC and Simon
   have prepared a test plan detailing what needs to be done to set
   up the measurements, what measurements we would like to do, and
   how long the test will take.  The game plan has been passed on
   to Elke.  DSC has already talked to Volker about using the magnet.
   He will pass on the game plan to him after it Elke signs off on it.
 - The tests would take place during the summer down time after the
   magnet refurbishment and field mapping take place.  We could have
   access in August/September.

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/).  DSC is still
   waiting for feedback and comments from the group.

Minutes prepared by Daniel. Send any comments or corrections along.