Minutes 12-13-2006
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FDC Weekly Meeting
Date: December 13, 2006
Participants: Daniel, Brian, Simon, Tim, Chuck, Roger, Fernando, Elke, Kim
Next Meeting: Wednesday, December 20, 2006 @ 1:30 p.m.
Design Issues
> Do we want the STB capacitors inside or outside the gas volume?
Pros: Kept with stable environment (reduce potential HV issues).
Cons: solder flux (must be cleaned), contamination from components.
==> We decide to put them inside the gas volume.
> Daughter board location on anode and cathode boards.
- Tim and Chuck reviewed their work to position the cathode and
anode daughter boards to ensure clearance with neighboring layers.
- We decided to allow the connectors to run from mounting rail
to mounting rail to spread them out to give sufficient space
for connectors and cables.
- Work needs to be done to make sure that there is sufficient
room for cables in the 5-cm annulus surrounding the FDCs.
Fernando provided the specs on the readout cables for cathodes
and anodes.
- Still need to iterate to define the extents of the different STB
boards.
- Roger and Kim will wait to layout traces until Tim and Chuck have
completed their work. Note that with the multi-layer boards that
will be employed, we will have to run traces on multiple layers
to allow for sufficient ground shielding between neighboring
signal lines.
- Fernando also needs to converge on the exact size of his daughter
boards. He is getting close and should have a preliminary design
completed by the end of the week.
- Fernando has identified connectors for the daughter boards and
will pass this information on to Kim and Roger. These connects
are surface-mount and come with the option of guide rails to help
with the insertion of the daughter boards.
> To give us flexibility in connector choices, we will increase the
anode-cathode spacing to 6 mm from 5 mm. This more closely satisfies
our electrode design rule-of-thumb of half-gap/cathode pitch = 1
as the strip pitch is now 5.5 mm.
> The STB resistors will be placed outside of the gas volume, close
to the daughter board connector.
> Fernando has identified output connectors for the daughter boards
with locks to keep the cables in place.
> Fernando has been thinking about the LV design for the daughter
boards and a possible bus distribution system. More details to come.
> Simon and Fernando have worked out details of the FDC monitoring
boards and readout. These boards should include temperature and
humidity monitoring.
> Brian will pursue construction of a carbon fiber annulus for the
wire plane support frame. This may be stiffer than g10 to support
the wire tension. This is the only frame in the FDC that doesn't have
an o-ring groove (which is difficult to machine).
> We reviewed the planned HV distribution for Roger. One mother cable
(with 12 babies) per wire plane (6 sense, 6 field).
Budget Discussion
> PC Boards: Fernando provided a quote for the STBs and HVTBs from
Advanced Electronics.
> Daughter Boards: Fernando will send quote by the end of the week.
> Preamplifiers: Fernando has gotten modified numbers from Mitch. He
will provide them by the end of the week.
> Cooling: Tim will put together a quote on a forced air/radiation
system by the end of the week. Fernando liked the approach and
believed that it should be sufficient.
> Mounting and Support System: Tim will provide a quote for the rails,
the adjustable height cart, transfer system for insertion, and
cable support/strain relief system by the end of the week.
> Ground Planes: Brian is working on this and will provide a quote by
the end of the week.
> Monitoring System: Simon will provide a quote by the end of the week.
> Wire Winding: Brian will contact Karen Kephart this week.
Cathode Mechanical Mockups
- Brian is working on this to have all of the parts and pieces
ready before the end of the year. As we had no time, the progress
was not discussed during the meeting.
Minutes prepared by Daniel. Send any comments or corrections along.
