Pump down and venting of chamber is controlled via the TUDA epics.
http://www.triumf.info/wiki/tuda-tactic/index.php/EPICS_and_ISAC_status
(I hope this procedure is correct! If not then epics will stop you from doing something stupid and you can't open valves and turn on pumps if the conditions are not right)
Pump down:
- Check manual valve to turbo pump and vent valve are closed.
- All interlocks should be closed except PV5 and RV5.
- Pump down using roughing pump first, BP5.
- Open manual valve to roughing pump slowly.
- Once CG5 is < 250 mT you can turn on turbo. Close RV5 first then turn on TP5, the turbo pump, and open BV5.
- Turn on PNG5 ion gauge when vacuum is good enough.
- When PNG5 is < 1.e-5 T it's ok to turn on cryo pumb.
- For cryo pump CG5C has to be < 150 mT. Turn on CP5 and open GV5..
- If CG5C is not low enough in pressure then open RVC5 while monitoring TURBO V-550 monitor and making sure Power < 55W. You should see the vacuum pressure on CG5C going down. Close CG5C is turbo power is > 55 W and wait for it to go down to 27 W or lower. Repeat process till pressure is low enough to turn on cryo pump CP5/
Cooling:
- Turn on chiller by switching on and setting temperature to - 15 deg C or something low.
Venting:
- Bring back chiller to room temperature. If broken then turn off and wait 30 min. Preamps should be turned off.
- Close BV5 and turn off TP5, turbo pump.
- Close GV5 and turn off CP5, cryo pump.
- Turn off PNG5 ion gauge.
- All interlock should be closed to the chamber.
- Close manual turbo valve and check manual vent valve is closed.
- Open VV5, the vent valve.
- Wait 30 min for turbo to spin down 10%. Turn open manual vent valve slowly by observing pressure on manual meter and CG5 pressure gauge.
NOTE: If you're venting while preamps are still a little cold use dry nitrogen gas when venting.
Some info on previous pump down and cooling times:
https://elog.triumf.ca/Tuda/ISACII/185 (first pump down)
https://elog.triumf.ca/Tuda/ISACII/188 (subsequent pump downs) |