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FDC Weekly Meeting

Date: July 3, 2008

Participants: Daniel, Simon, Brian, Fernando, Mark, Jim, Elke, Eugene

Next Meeting: July 10, 2008 @ 1:30 p.m.

Cathode Planning

 - Roger sent the PR around for feedback and comment.  Necessary
   blessings have come from Fernando and Bill on the layout and
   design.  Elke has provided procedural instructions that have been
   taken into account and she signed the paperwork.  The PR has been 
   sent on to procurement.  As soon as a delivery date is better known, 
   more details will be provided.
 - Fernando discussed the electrical testing plans.  The biggest thing
   for checkout and board qualification is to complete a series of
   resistance measurements on all boards.  This includes the resistance
   of each strip and the isolation between neighboring strips.  While
   inter-strip capacitance measurements will be needed at some point,
   they are not necessary for vendor qualification.  Fernando will
   check around to find out if someone has an appropriate unit that
   can be borrowed (e.g. from the SVT group in Hall B, from Gerard,
   or from Mitch).  Fernando will put together a test plan document
   (including proper handling specifications) and will circulate it
   for comments and feedback.  We want to have the plan finalized and
   all equipment on hand to begin testing as soon as the boards are
   in our hands.  This should be in roughly 3 weeks. 
 - We briefly reviewed the current concepts on how to cut the precision
   edges on the cathode boards.  We will work to develop a plan and
   order what we need to complete tests before cutting the real boards.
 - Fernando had some feedback for Roger the rigid flex assemblies.  We
   will follow up with Roger on his plans.  Fernando believes that with
   the new design for the assemblies, further solder tests will not be
 - Roger is working with the Allflex representative to find whatever
   information is available from Nippon on the raw material specifications.
 - 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).  As this box is not needed for
   at least several months, this work is not super high priority.
 - We should check with Allflex to have them let us know when the
   shipping box has been delivered.

Full-Scale Prototype

 - Brian checked on the status of our granite table order.  The word
   now is that the table will not arrive until the first of August.
 - The work on the assembly jigs is in the queue in the JLab machine shop.
   The work should be completed by the 3rd week of July.
 - Brian checked on the electrical work to connect the clean tent to
   power.  It has not started yet and he will follow up on this to find
   out when it will be done.  We will also agree to let another group
   use the clean tent before we move in as we are behind schedule.
   Brian will provide a statement on this to Elke, who will pass it
   along to Dennis Skopik.
 - 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

 - DSC circulated a cathode R&D planning document to the group for
   feedback.  Feedback should be provided over the next week to finalize
   the task list.  DSC will then use this to create a work time line so
   that we can understand the impact on the FDC construction schedule.

Test Frame Wire Winding

 - Elke has signed the paperwork for the continuation of the Phase 1
   wire winding contract with IUCF.  The paperwork has now been moved
   on to the contract folks and will be finalized very shortly.
 - The shop completed work on drilling holes in our wire frames (after
   some priority negotiations with Elke).  DSC and Simon packed up the
   shipping crate with two frames and it was sent to IUCF on Monday.
   The frames arrived at IUCF this morning and they will inspect them
   for any damage incurred during shipping.
 - Brian will provide information on the two frames so that we can
   tell IUCF which frame to use for the winding tests.
 - 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 is working on upgrading the system readout electronics.  He
   prepared a time line for the system work and DSC reviewed it for
 - Micah completed a series of flatness measurements on one of our
   backed cathodes and our high tension cathode.  The backed cathode
   shows a surface flatness profile that has a 6 mm range!  Yikes.
   The high tension cathode has a flatness profile range of 200 microns.
   Micah did measurements with the laser running along the strips and
   transverse to the strips.  These profile data have some very
   interesting and complex patterns that we need to understand a little
   better.  We also need to study the effect of these surface profiles
   on our cathode coordinate reconstructions.  Is the value that we
   have in our resolution error budget table sufficient? 
 - Micah and David put together a list of parts 'n pieces for the
   measurement system upgrade.  DSC has worked with Lorelei to order
   the parts.  They should arrive in a week or two and then the
   upgrade work on the system will continue.
 - Micah still needs to perform flatness measurements as a function
   of rotation angle so that we can better understand the effects
   of gravitation sag on the cathodes.

Cooling System Tests

 - Fernando has completed a series of tests of the cooling system
   as a function of the temperature setting of the water reservior
   for fixed flow rate.  A flow control valve has just arrived an
   will be installed next week.  The plan is to perform more cooling
   studies as a function of flow rate for fixed temperature.  Fernando
   will prepare a GlueX note when the studies are finished.

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 is continuing his work to specify the ASIC dynamic range.
   He has taken lots of data with the small scale prototype and has
   completed a series of simulations using GARFIELD to connect the
   cosmic ray and X-ray source data to what we expect with pions and
   protons.  So far he has been able to use GARFIELD to reproduce
   the chamber data with cosmics and X-rays.  He will now work to
   specify the dynamic range for cathode and anode and update the
   first draft of the associated report.  This work is posted as 
   GlueX-doc-1070.  He will be giving a report soon to the Hall D group.
 - Fernando has suggested taking some data with a 90-10 Ar/CO2 mixture
   to ensure that we fully understand the 55-Fe data and to allow an
   easier connection with the CDC data.  Simon will take this data


 - 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.