May 16, 2011 CDC Design
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Contents
Meeting Time and Place
Tuesday May 16, 2011 at 2pm At Jefferson Lab, the meeting will be held in room CC F326
Connections
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Meeting Purpose
To finalize upstream plenum details so parts can be fabricated
Agenda/Discussion
- Transition board - ok to Fab samples? [1]
- Fabricate transition board as shown on Slava's dwg but make holes for grounding bus .050 for press fit of pin
- Change clearance from .070 to .080 for solder pad to grounding bus
- Swiss cheese plate - ok to Fab? 5/8 inch
- need to find 5/8 poly carbonate sheet (Tim)
- Need to see if we can find a 6mm crowfoot to install threaded gas seals (Tim/Gary)
- Holes for wire in swiss cheese to be .156 +.005/-.000in
- Gary to test threaded inserts in PC plate, Do Not Use self tapping inserts!
- Gary to check to ensure threaded gas seal is flush with top surface.
- HV board shielding - not discussed
- upstream plenum shielding - not discussed
- Strawtubes. - to ship 18MAY2011
Additional Notes from CMU
The CMU group wants to add that the following decisions were taken during the meeting. We summarize our understanding of these as follows.
- After the polycarbonate plate is attached to the chamber, we will support the chamber during electrical hook up using the polycarbonate plate.
- The support will be made using the flange that currently holds the aluminum endplate of the CDC.
- The ID of the polycarbonate plate will be machined to match the ID of the aluminum endplate so the flange will work.
- A discussion of load transfer and alignment of the polycarbonate plate to the inner aluminum hub was also carried out. Three options arose from this discussion: dowel pins, counter-bored plate and nothing. Our understanding is that both Tim and Gary felt that the first (dowel pins) would be best solution and would be pursued.
- Use a pair of dowel pins to both hold and position the polycarbonate plate to the inner hub. This solution both transfers the load an provides for accurate alignment of the two parts.
- Counter-bore the polycarbonate plate and notch the inner hub. This will provide load transfer, but will not allow for an accurate rotational alignment.
- Just use the planned 12 #8 bolts to transfer the load.
- As part of building a wiring prototype jig, CMU will check the depth of the holes for the aluminum bushing that hold the wires in the polycarbonate plate to make sure that the threads are flush with the surface. We do note that it is unlikely that the uniformity of the thickness of a large polycarbonate plate will be uniform enough to guarantee this everywhere on the surface of the plate.
Minutes from last meetings
- Discussed outer shell. JLAB will have this fabricated locally and sent to CMU
- Swiss cheese plate -
- decision to use 5/8" thick lexan was made,
- also need to increase hole for wires to o.156"
- Put labeling on plate for wire locations, use A01..., B01..BBXXX for rows 1-28. see if we can get label for every hole, if not, use every 10th hole
- JLAB to have swiss cheese plate made with above changes.
- Need to update threaded bushing to have a radius (.030 min) where wire exits - order 3600 and send to CMU
- Use Shore A70 durometer viton for orings, jlab to order 4000 and send to CMU
- Slave to supply info to CMU for conductive tubing. CMU to order
- Discussed possibility of individually shielding HV boards. Provision will be incorporated into the design
- Discussed fact that the board needs to be able to be inserted only 1 way. Fernando is putting provisions in to make sure.
- Beni submitted a table for the length of the cables - CMU to review this to see if they are in agreement
- Slava to provide full scale layout of board/ connector locations and CMU will use this to determine which wire goes to where on the connector.
CMU will supply this information to JLAB for incorporation to the drawing.
previous Action Items
- Specify thermal couples.
- Drawings for gas plenums.
