May 26, 2009 CDC Meeting

Meeting Time and Place

Tuesday May 26 2009 at 1:00pm At Jefferson Lab, the meeting will be held in room ??

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Notes from the previous meeting

1. Primex chamber gas velocity about 80 cm/s - Curtis will look at his numbers again.
   1. Curtis has updated the gas flow document with this information, (Gas Flow in the CDC). With nominal expected sizes, the gas flow can be handled with six rods (input) or four polyflow tubes (input). This requires an equal number of output lines.
2. Should the wires be strung at JLAB so broken wires during transport are not an issue? Will need to find space for this at JLAB - timeframe Nov 2010. Would Gary come here for the rest of the assembly? Would students be brought down from CMU?
   1. If the chamber is built at JLab, then CMU participation is not possible. However, we do feel that it would be appropriate to carry out the electrical hook up at JLab to allow for the possibility of replacing any wires that may have broken during transport.
3. Should there be some type of cleanroom used for CDC assembly?
   1. We will set up a clean (enclosed) area at CMU and work with as clean of practice as is possible. We will not have a rated clean room available at CMU.
4. Gary found conductive rubber tubes .030-.050 in. diameter. Should be good for 1mm single diameter pin.
   1. When we have pins and feedthroughs, we will need to carry out some tests on the best way of kooking this smaller conductive rubber to the smaller pins.
5. Do we need a shoulder on the crimp pin? Is a counter bored hole adequate to stop the pin from going in too far and moving from wire tension?
   1. It is very important that the tapered pin not be able to creep under the wire tension (30g). The only way that we can see doing this is to have a shoulder on the crimp pin to provide a positive stop.
6. Gary found transit to accurately locate plates relative to each other within .003 inches.
7. Curtis suggested using 2 inch rods for initial alignment of plates before gluing straws.
   1. Actually, this was Gary's suggestion, Curtis just restated it during the last meeting.
8. Need to determine how much room is available on inner edge of end plates for tooling.
   1. Our best estimate is that we need 1/4 inch on the radius to hold the plates. We would also like that the inner shell not conflict with this. If we use a thin glued wall, it seems that we should be able to have the gas plenum wall in a space that is no more than 1/8" from the innermost tube, which looks like it leaves about 3/8" for our holding fixture.
9. Does the gas plenum ever need to come off?
   1. We note that in any scenario we have been considering, removing the upstream gas plenum is very likely to render the swiss-cheese plate not reuseable. Thus, we would need a new plate. Under such an assumption, whether i

Agenda

1. Discussion of the new Lumina Straws.
2. Assembly procedure (Version 2)
3. Gas flow into chamber (Gas Flow in the CDC Version 2)
4. AOT