Venting

Prerequisites

• If ending operation with the x-ray beamline, make sure that the pulse picker is closed, stopper S6 is inserted, hutch search is broken and glass window inserted.
• Stand next to the chamber during the procedure to be ready to react once the chamber is vented and avoid over-pressurization.

Venting procedure

• Press CLS on all opened gate-valves connecting a vacuum line to the chamber (TC1-VGC-01, TC1-VGC-02, TC1-VGC-03, TC1-VGC-04)
• Press OPN on TC1:VGC:11
  - a new window will open
  
• Press Yes and close the window immediately
  - chamber will start venting
• Optional: Press OPN on on TC1:VGC:12 when allowed
  - after a while, doors can open and you will hear the compressed dry air intake loudly
• Press CLS on TC1:VGC:11, and on on TC1:VGC:12 if necessary
• Open the chamber doors and let some time to ventilate the chamber before breathing inside the chamber

Turbo pump shutdown

It is not mandatory to shutdown the turbo pump during each venting cycle. We usually let it run when venting for a short time during a shift. If venting for a longer time between two shifts, we usually turn off the turbo pump but not its rouging. The following steps describe a full shutdown of the turbo line after venting.

• Press STP next to the turbo pump logo
  - let the turbo spin down for at least 15-20 minutes (the off-status logo on the turbo does not mean the blades have stopped spinning)
  - stop at this step if you will restart the turbo in less than a day, additionally you can set the scroll ballast to level I (it can be set to level 0 or I during operation)
• Press CLS on SEW-VGC-15
  - make sure ballast level is set to 0 before going to the next step
• Open mechome
• Go the tab "User Devices"
• Open the panel "User Sentry PDU"
• Turn Off "Roughing pump PTM 02 (turbo 2)"

List of PVs associated to the vacuum system components

Pumps

Gate-valves

Logical permissions on the gate-valves 

Pressure gauges