Minutes 11-29-2006

FDC Weekly Meeting

Date: November 29, 2006

Participants: Daniel, Brian, Simon, Tim, Chuck, Roger, Fernando

Next Meeting: Wednesday, December 6, 2006 @ 1:30 p.m.

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Dummy Cathode Boards

 - We reviewed the design of the dummy flex boards for Fernando.
 - Brian has completed the purchase request and given it to Elton.
   We are now waiting for Will Brooks to sign this before it goes
   out.
 - Given that the flex boards will take ~6 weeks for delivery once
   will signs the paperwork, DSC told Brian to begin work on mounting
   ``kapton only" boards to develop the required procedures.
 - For Rohacell mounting, Brian should come up with a game plan and
   begin work after we go over the plan.
 - For tensioning procedure, Brian should request the machine shop
   to construct the full-scale tensioner (they have all the materials).
   This system represents our back-up procedure.

Flatness Measuring System

 - ATLAS has designed and successfully used a non-contact system for
   measuring the flatness of their cathode planes.  Neither Simon nor
   Brian has had any luck getting someone from ATLAS to respond to
   our questions on the system.  However, they will keep trying.
 - We discussed how the flatness measurement system might work.  We
   talked about capacitance measurements and laser interferometry.

Fernando's participation

 - We reviewed the issues with cooling the preamp daughter boards.
   This included discussion of the suggestions by Mitch Newcomer.  DSC
   gave Fernando a copy of this email.  Fernando will think about this
   and take the design a little further.
 - Fernando is interested in designing the preamp daughter boards.
   He will will to provide a sketch of the boards which can lead us
   to better estimate the cost for the FDC budget.
 - We discussed the issue of placing a ground plane near the cathodes.
   DSC had a 2003 email from Fernando and Elliott Wolin warning about
   signal degradation on the cathodes.  Fernando said that our 5 mm
   cathode-ground spacing is adequate.
 - Fernando will think about our grounding plane design (aluminized
   mylar vs. graphite vs. conductive ink) and recommend what he thinks
   is best.
 - Fernando will contact Mitch Newcomer regarding the possibility of
   including a discriminator on the ASIC chips.  This level of
   electronics is required for the anode connections to the TDC.

Polyethylene Frames

 - DSC suggested to replace G10 with polyethylene (CH2) in the chamber
   to reduce the thickess.  G10 is twice the density of CH2.  Brian
   thought that this would be fine for the spacers, but that we should
   plan on using G10 for the circuit boards to provide better stiffness.
 - DSC will investigate whether CH2 is chamber-safe.

Preamp Cooling

   Fernando reviewed one possible idea for a preamp cooling system
   using brackets connected to external heat sinks (mounted on the top
   of the ASICs).  Could we bring these brackets to the inter-package
   rods to dissipate the heat?  More discussion to come after
   Fernando thinks about this.

Electronic Components

   DSC will provide Roger with our specifications for the chamber
   components and ratings.

HV Connections

   We discussed how to connect the HV from the baby cables to the
   chambers in a robust and reliable manner.  Fernando and Brian
   recommended using pig tails.  We could use Reynolds-type connectors
   (small profile HV connectors -- about lemo size) and bring the
   connections to a manifold downstream of each package.

FDC Budget

  - We went over the open issues with the FDC budget and updated a
    few items.  DSC, Simon, and Brian will continue to fill this out.
    It is due to Elton is about 2 weeks.  Hopefully we can converge
    on the ``big ticket" items in about 1 week.  
  - Brian is currently in contact with Karen Kephart about the costs
    for stringing the FDC chambers.
  - Fernando is working with us to estimate the costs for the preamp
    daughter boards and the cooling system.
  - Tim and Chuck are thinking about the cable support system, the
    FDC exoskeleton, the rail system, and the mounting system.
  - Stuffing of boards estimated from Brian Kross at $100/board.

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