beam line assembly (A. Hernandez)

preparatory work, can be done any time:
1) Cut/fit 2 1″ layers of lead bricks for the bottom shielding. It doesn’t need to go all the way to the edge but it should be within about 1″ on all sides.
2) Design and fabricate a base plate to which the pump chamber itself mounts. The brackets that are on the exiting stands are probably a good assumption for what will be mounted to the plate to hold the chamber and turbo pump. The chamber/pump assembly weighs about 75 lbs. and will be oriented anitparallel to its lowest gravitational energy state, so the mounting will have to be substantial. Tabs have been installed on the stand for mounting this plate and/or side plates.
3) When turbo pump controllers arrive, install and test full pump setup. A vacuum in the range of 10^-6 torr should be achievable using the turbo/rough pump setup we usually use pumping against the large vacuum valve on the other side of the turbo pump.

installation, should be done only when preparatory work is complete
1) Shut down Morseified turbo controller and rough pump and wait for the turbo to spin down (may take hours).
2) When the turbo has slowed down, wheel over a tank of argon and very slowly backfill the beam tube and pump stand. Purposely hold the connection between the tank and tube fill fitting very loosely so it is not possible to pressurize the fragile beam tube.
3) Detach the pump stand at the flex coupling.
4) Move the new pump stand in to place.
5) Install the lead, mounting plate, chamber, and turbo pump.
6) Attach the chamber to the beam tube with a new 8″ copper Conflat gasket.
7) Attach a blank flange on the open end of the chamber.
8) Turn on the rough pump and open all the valves. The beam line should pump down near 10^-3 torr in fairly short order. If it doesn’t, turn off the pump and listen for huge leaks caused by improper gasket installation.
9) With the pressure below 1 torr, start the turbo pump and let it come up to speed. The vacuum pressure should be down in the 10^-8 torr range within 24 hours. If not, leak check, repair, repeat pump down.


1 Response to “beam line assembly (A. Hernandez)”

  1. 1 Andrew Hernandez July 1, 2011 at 3:04 pm

    I will begin working on this next week when I come into lab. I have a question pertaining to the placement of the turbo pump on the new pump stand. With the existing stand the turbo pump is mounted vertically directly below the aluminum chamber that is present now with the glass end piece. With the new stand there is a steel plate on the entire top of the stand so how is the turbo pump suppose to fit directly below the xy steerer chamber when there is going to be lead and a steel plate in the way? I think I am misunderstanding the exact placement of the turbo pump

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