Minutes 2-14-2008

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FDC Weekly Meeting

Date: Feb. 14, 2008

Participants: Daniel, Mark, Simon, Brian, Kim, Chuck, Fernando, Bill

Next Meeting: February 21, 2008 @ 1:30 p.m.

Test Frame and Prototype Wire Winding

 - IUCF is now reviewing the paperwork that we sent them on the Phase 1
   and Phase 2 winding of the prototype planes.  We expect to hear
   back from them this month.  DSC has been contacted by the IUCF folks
   and expects that there will be some back and forth on the language
   before anything is signed.  It seems clear that no winding will take
   place this month.  An update will be given when more news is available.
 - DSC has contacted the IUCF folks about what supplies they want us to
   bring for the Phase 1 winding.  This information will be passed on
   to Brian when it is available.
 - Brian has checked with Stan and the ISM team that he is serving on
   and has said that there will be no problems with him traveling to
   IUCF when the Phase 1 winding takes place.
 - DSC has asked Brian to check the sense and field wire quality.  DSC
   has contacted Steve Christo from Hall B about the possibility of
   checking the wire under an electron microscope here at JLab.

Full Scale Prototype

 - DSC has completed a stripped down budget estimate for a half package
   full-scale prototype.  This information has been sent to Elke for
   review.  When we hear back from her on the money available in the
   budget, we will iterate on our plans if necessary and then move
   immediately to begin the procurement phase for the prototype.

Cathode Boards

 - Roger will take over all aspects of the cathode flex boards.  He
   is already responsible for the design, but he should take care of
   paperwork, procurement, QA planning, etc.  Roger should also work
   now to contact the cathode board material supplier and the circuit
   board company to get them to understand our flatness requirements.
   Why do the boards come to us with clear surface defects and can these
   be eliminated?  We also need to work with these companies to specify
   board handling and transport.
 - Roger needs to find out what QA tests will be done by the board
   house to verify the quality of the boards (complete set of resistance
   checks would be a minimum).
 - Roger needs to find out from the board house whether we can
   have the cathodes delivered with the cut-outs already in place
   at the center and possibly the edges of the boards for gas flow.
 - Roger needs to be on contact with both the flex board material
   supplier and the board house on the minimum copper thickness that
   we can get on the cathodes.  We sure would like the option of
   0.5 micron or 1 micron thick copper strips (assuming that the 2 micron
   copper thick strips show no problems in the small-scale prototype).
 - Roger was away on vacation this week, but we still had a lengthy
   discussion on the ground pour layout on the cathode boards.  We
   want to have as large a ground pour area as possible, and we also
   need to take care that we do not have a complete current loop for
   eddy currents in the case of a solenoid magnet quench.  Roger is
   aware of these issues, but we need to have a separate meeting with
   him to finalize the cathode layout.
 - We discussed briefly the plans for connecting the ground between the
   three separate flex boards that make up one cathode board.  The current
   idea is to rely on a thin layer of conducting epoxy, but this needs
   to be finalized and prototyped.
 - DSC would like Roger to prepare a document on QA for the cathode
   boards when they are returned from the board house.  This document
   should be reviewed by Fernando.

Composite Cathode Discussion

 - Brian and Denny continue work on the composite cathode sandwich
   prototype.  Progress has been minimal in the past week as Brian
   has been out sick.  At the current time, one cathode plane has
   been prepared from the three separate pieces of dummy flex board,
   and these have been epoxied to the composite ring.  The 2-mm
   thick Rohacell backing has been glued into place.  The next cathode
   board will be laid out tomorrow and finished on Tuesday of next
   week followed by attachment of the ground plane and the connection
   of the two cathode planes into a sandwich.  We still need to finalize
   how we will connect the external ground to the ground planes and to
   prototype this design.
 - Brian will prepare a construction procedure document with a full
   set of photographs as he constructs the last prototype cathode.
 - Bill is responsible for preparing a document to lay out the costs
   associated with the laser interferometry flatness measuring system
   that he has identified.  This document should also include a brief
   description of the measurement requirements and measurement plan.
   This will be discussed in the group and iterated on before being
   passed on to Elke for review.  If the budget is reasonable, Elke
   will give the green light to begin procurement.  Bill should also
   talk to Casy Apeldorn in the JLab machine shop about our plans and
   need for the horizontal milling machine.  Of course, any expected
   charges from the machine shop should be included in the budget

Gas Window/Frame Design

 - With the new idea of having each FDC package as a single gas volume,
   we need to design the gas windows and frames.  Brian will come up
   with a design and circulate for comment.  When the design is finalized,
   we can have Chuck put it into the CAD model.  We still need to determine
   the thickness of the gas windows.
 - We again reviewed the new plans for the gas volume definition and
   Brian will plan on designing a gas port system for inclusion in the
   Rohacell of the cathode frame (between the cathode flex boards and
   the ground plane).
 - We would still like to model the gas flow with this new design.
   Some combination of Bill and Chuck need to develop a model to give
   to Dave Meekins to run his flow calculations on.  We want to make
   sure that we have good flow and gas distribution through our active
   gas volume.  This is also necessary to finalize what holes are needed
   in the cathode planes.

Cooling System Update

 - Bill is working with Denny and Fernando to put together a test setup
   for the cooling system.  This will include a water-based chiller
   borrowed from Hall A and a cooling loop with appropriate sized plumbing.
   Bill has already gotten several brackets that attach to the preamp
   that will clamp to the cooling loop.  He has brackets made in copper
   and aluminum.  The preamp card will be supplied by Fernando and is
   one of the version stuffed with 3 ASIC chips.  The board will be
   outfitted with a thermocouple for temperature readback.  The board
   will then be packed in some amount of insulation to mock up the
   real FDC environment inside the solenoid.
 - Bill will be in charge of the tests and will take all of the data
   relevant to be sure the cooling system can supply the required
   cooling power.  He will also work to define the flow parameters of
   this water-based chilling system for the ultimate Fluorinert system
   that is planned.  Bill will also document the test setup and take
   lots of pictures.
 - Due to lack of time, progress in this area was not discussed.  We
   will bring it up at our next group meeting.


 - We discussed the modifications needed in Brian's assembly jig for
   the circuit boards to clear the pre-stuffed components.  The radius
   of the components will be different on the STBs and HVTBs.  Kim will
   provide Brian with the clearance regions.  Brian will also include
   some sort of alignment marks on the jig to ensure proper placement
   to avoid crushing the components.
 - We will stuff the prototype chamber boards here at JLab.  DSC and 
   Fernando will meet with Kim and Greg Arnold next week to discuss
   the plans and the issues.
 - Fernando will prepare a writeup to detail the board stuffing and 
   cleaning procedures.  This document should clearly delineate between
   the stage 1 board stuffing (pre-winding) and the stage 2 board
   stuffing (post-winding).  It should also include clear handling
   instructions for the stage 2 winding to ensure that there are no
   possibilities of damaging the wire planes or breaking any wires.
 - Kim will prepare a QA manual for the wire frames to test them after
   we get them back from the board house.  She will also be responsible
   for initial QA tests.
 - Kim has essentially completed the layout of the STBs and HVTBs (with
   one minor issue with the grounding on the HVTBs) and the board designs
   have been sent out for quotes.  Kim has already received quotes from 
   two sources for the board connectors and components. The prices are 
   higher than anticipated due to the requirements of minimum order size.  
   The components are very cheap, the issue is the connectors.  One set of 
   connectors that is required has a VERY long lead time of 3 months or more.
   Kim will move immediately to place this order.  The rest we will decide 
   on over the next several weeks.  To keep costs low, we will probably use 
   several different companies for the procurement of these parts to avoid 
   the minimum order size issues as much as possible.
 - We discussed the issues of eddy current on the wire frame circuit
   boards in the case of a magnet quench.  We have a design the presently
   does not have a complete loop, so we are satisfied here.  The other
   issue that was discussed was the connection of the ground to the
   circuit boards.  The ground will be connected via a spade-type connector
   that Fernando has identified.  This same connector will be used on
   the cathodes as well.  Ground will be distributed from circuit board to
   circuit board via the Erni-style connectors.

Small-Scale Prototype

 - Brian will mount the +/-75 deg cathodes for the small-scale prototype
   as soon as he is done with the composite cathode prototype.  Hopefully
   (as I have been saying for several months), this will happen next week.
   We think that we have all the necessary parts gathered for this work.
   Simon plans on installing them shortly after thereafter for testing.

FDC Construction Space Request

 - DSC prepared a space request document for the FDC construction that
   was given to Elke.  She will pass this on to the facility management
   folks who will hopefully work with us to find the required space for

FDC Mini-Review

 - The committee report from the mini-review has not yet been delivered.
   As soon as it appears, it will be circulated to everyone for review.

Meeting on ASICs

 - We had a meeting with Mitch Newcomer and Gerard Visser on Feb. 13 to
   discuss the current studies and future designs plans for the ASICs.
   Mitch and his group still have a lot of design work to complete, 
   although they have made progress in all areas and they know exactly
   what is left to be done and how long the work will take.  
 - We have already made the decision to not submit the second version
   of our ASICS in April.  The time is too short and we still have to
   much work to do.  The next submission time is believed to be in
 - We need to clearly specify the gain requirements and dynamics range
   for the ASICS from both the CDC and FDC systems.  It may be that
   the design that is required for the FDCs is not compatible with the
   design required by the CDC.  The required tests for the CDC and FDC
   were discussed and clarified.
 - For the rest of this year, we will only have a total of 10 stuffed
   preamplifier daughter cards.  The CDC folks only need 1 or perhaps
   2 boards.  The FDC folks would like 4 cathode boards and 1 anode
   board in order to fully outfit the small-scale prototype.  We agreed
   that this will happen soon.  Gerard has sufficient boards and parts
   for all of the needed shapers.  

Meeting on LV/HV System Design

 - Fernando and DSC met with Joe Beaufait this morning to continue our
   discussion on the design and layout of the FDC (and CDC) LV and
   HV systems.  Joe was brought up to speed on the current design plans
   that have evolved slightly since our last meeting with Joe about 3
   weeks ago.  There was significant discussion on the number of
   cables that need to connect to the chambers and how much redundancy
   is needed in the system.  We will converge on this and Joe will start
   preparing drawings.  We will meet again within the next two weeks.

Mechanical Prototype Proposal

  - DSC has prepared a request for funds and personnel for the construction
    of a mechanical prototype for the FDC.  The proposal was briefly
    discussed and DSC forwarded the request to Elke after the meeting.

FDC Insertion Planning

  - Bill discussed his idea for the rail system that the FDC will ride
    on inside the solenoid and his planned attachment scheme.  This was
    met with favorable review.  Bill still needs to decide on the size
    of the rails themselves.  The rails that he is leaning towards are
    from Igus rail (the W series to be exact).
  - We need to define the required space for the FDC cable bundles that
    will reside outside the CDC.  Chuck has already been looking into
    this, and has already been in discussion with Curtis.  The CDC will
    be affected in that they will have to remove their outermost layer
    of straws.  We need to have a final set of drawings and have a final
    group discussion on this issue before we get too far.
  - We need to have a discussion on the cable runs and plans for being
    able to install and extract the FDC system without having to
    disconnect the signal cables.  Also during the insertion and extraction
    procedures, there can be no stresses applied to the preamp boards
    or cables.  
  - Finally, we need to come up with a design for how we will bring
    the signal cables and power cables out of the solenoid.  It appears
    that the gas and cooling lines could come out on the downstream side
    of the solenoid.

Upcoming Reviews

  - The combined tracking/PID review for Hall D is scheduled to take
    place on March 27 and 28.  At this point, we are converging on
    a charge and the list of speakers.  We have to prepare talks and
    backup materials for the FDC, CDC, and charged particle PID systems.
    The details will be worked out over the next week or so and
    preparations will continue from now until the review.


 - 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.

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.