The nitrogen shield skirt now has aluminum foil on both beam openings. This means you must always take care in pumping down the magnet otherwise a quick change in pressure will rip them out. Fixing these or even knowing that there is a problem will be hard, so be careful.
1.) Close the butterfly valve to the dry backing pump all the way and turn on the backing pump
2.) Very slightly open the butterfly valve just a crack and listen to the pump. It will tell you when the pressure drops.
3.) When the pump quiets a bit (about 15 minutes) open it a bit more. Do this in about 3 or 4 steps until all the way open.
4.) Let pump down to around 1X10^-2 torr and then prepare to turn the turbo on (turbo will start up fine at ~1 torr but its better to wait and get lower pressure first).
5.) Turn the turbo on and let pump down. If the system was open to the atmosphere where air and moisture can get in, it's better to pump down and backfill with nitrogen gas a few times
6.) If all goes well you should get down to something times 10^-5 torr in less than 5 hours. You will need to let it pump down until you get to a low 10^-6 torr before its ready for cryogenics.
7.) If you need to bring it up to atmosphere to do maintenance backfill again with nitrogen gas. If you let atmosphere seep in it will take longer to pump down.
