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FDC Weekly Meeting

Date: June 12, 2008

Participants: Daniel, Simon, Fernando, Kim, Roger, Mark, Elke, Micah

Next Meeting: June 19, 2008 @ 1:30 p.m.

Cathode Planning

 - Roger is working to finish the design drawings for the cathodes.
   Before they are submitted, we need Fernando to bless the electrical
   aspects of the board layout and we need Bill and Chuck to bless
   the gas hole layout.
 - Roger circulated his list of handling specifications.  In this
   document, there were a number of conditions (electrical problems
   and creases) that would cause us to "reject" a board.  DSC would
   like Roger to clarify this with the Allflex sales representative.
   We need to have some language in the purchase order that covers
   us should there be any board problems.  If there are problems with
   the boards that would cause us to reject them and we cannot get
   new boards, then the money is gone and the project may be in trouble.
 - We received a quotation from Allflex for 6 sets of 2 micron Cu
   boards and 6 sets of 5 micron Cu boards.  The total estimate is
   for just under $20k, which happens to be the ceiling that Elke
   gave us.  
 - Additional solder tests of the rigid-flex assembly to the cathode board 
   mock up will proceed after Roger gets the hot air pencil from Fernando.
   This work will wait until the cathode board PR is completed.
 - Due to the height of the solder connection between the cathode board 
   and the rigid flex assembly, we will have to revisit the design from 
   the standpoint of adding clearance pockets on the surfaces that mate 
   up against this solder region.  Chuck is responsible for looking into
   this and letting us know.
 - Brian will modify his Lucite box design for storage of the completed
   cathode planes.  The cathode planes can stack upon one another
   (unlike the strung wire frames).  He will make some minor modifications
   to the existing box drawings and prepare the PR.  This work will
   proceed in July when Brian gets back to town.
 - Bill found a precision straight edge 1.5 m long for $750.  We can
   decide in the upcoming weeks if this is appropriate to purchase to
   cut our cathode boards to width.

Full-Scale Prototype

 - Greg Arnold's group is nearly done with the soldering of the HV
   capacitors to the STBs and HVTBs.  In all we will have 5 complete
   sets of boards.  In the next few days, all completed boards will
   be handed over to Simon.
 - The order for the 5 ft x 5 ft granite table has now gone out.  The 
   table will take 4 to 6 weeks to arrive.
 - The drawings for the aluminum tooling plate used for construction of
   both the wire frames and the cathode frames have been completed and
   turned over to the JLab shop.  They will modify the existing tooling
   plate and construct a second.  This work will be completed in 2 to
   3 weeks of time.
 - Brian found that the power cord for the clean tent did not reach any
   of the recepticles in the clean room.  He made a request to plant
   services to have an outlet installed.
 - Brian and Bill will work to update our wire frame construction sequence
   document.  Brian will provide a first draft to Bill who will work to
   polish it up.  We would like to provide this to Casey so his group
   (and of course ours) can full understand the procedures.  This work has
   not yet gotten underway.

Cathode Prototyping

 - No work done on cathode prototyping this week.  Still need to pursue
   techniques to tension cathodes to a particular (pre-determined) point.
   We still need to pursue mechanical solutions (fixed weights to define
   the tension).  More work when Brian returns from vacation.
 - We will try to develop a cathode tension measuring system using our 
   laser measurement head.  The procedure will be to direct a puff of 
   air at the center of the cathode and measure the amplitude fluctuation 
   vs. time through the laser measurement system.  Fitting this amplitude  
   distribution will give us (hopefully) the fundamental frequency that 
   we should be able to convert into the membrane tension.  More to come.

Test Frame Wire Winding

 - We had a teleconference with IUCF earlier in the day to discuss how
   we would proceed in the short term on completing Phase 1 work for
   the test winds.  We decided that DSC and Keith will work to come up
   with a specific task list for what must be done.  Keith and Vladimir
   will then work to prepare detailed time estimates for each task, an
   estimated budget, and a time line.  IUCF made it clear that when the
   next portion of Phase 1 goes into effect, the FDC work will be the
   highest priority of the wire winding lab.  Elke and DSC had discussions
   about traveling to IUCF to meet with folks out there.  This should
   be organized in the near term.
 - 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.  DSC reviewed the
   existing Hall B documents to give folks a flavor of how these
   documents have been prepared in the past.  We need to make decisions
   on what is required for the FDCs.

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.

Cathode Flatness Measurements

 - Micah has now taken ownership of the cathode flatness measurement
   system.  He has gotten everything working with the system and
   completed several scans to reproduce basically what Denny measured.
   Micah noted that the system still has too much vibration.  Micah
   should ask Tim to look over the system and to provide feedback.
   Also an issue is that the frame support system is too floppy and
   is not holding the cathode flat.
 - Micah is working to gather the parts and pieces necessary to
   turn the measurement system into an automated system.  He has
   gather a VME crate and a VME controller module.  This work should
   move forward nicely over the next several weeks.

Cooling System Tests

 - Denny reassembled the preamplifier cooling system in F117 and set
   the flow and temperature.  Fernando is getting ready to perform the
   cooling system measurements.  Bill has ordered a flow control
   valve that will arrive shortly and be installed in the system.

Gas System Design

 - Vladislav (Slava) Razmyslovich is working on a preliminary layout
   of the gas handling system for the CDC and FDC in preparation for
   the upcoming systems review.  We will sit down with him in a
   specialized meeting to review the design concepts when we get a chance.

STB/HVTB Discussion

 - Kim needs to provide an instructional writeup for the Phase 1 and
   Phase 2 wire frame PCB component attachment.  This is on her to-do
   list, but is not a high priority for now.

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.

Small-Scale Prototype

 - Simon has posted a first version of the FDC ASIC writeup.  This
   work is posted as GlueX-doc-1070.  Folks should look this
   over and provide feedback.  This note still is missing the final
   specification for cathode and anode dynamic range, but Simon is working
   to converge on this.


 - 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.