EVACUATING THE DELAY-LINE TANK
VACUUM PUMP PROCEDURES

Last update: February 1998

Vacuum system Startup

Inside the main building, next to the dewar pump:

Make sure that the backfill valve on main the tank is closed.
Close butterfly valve.
Close solenoid forline backfill valve.

Outside de the main building, on your left when you face IOTA entrance door:

Close HOKE valve on Roots Blower input.
Start Main Pump (wall switch).

Inside the main building, next to the dewar pump:

Slowly open butterfly valve (1 minute). Do it slowly because rapid opening will result in ribbon cables and other items occulting beam.
Move butterfly valve lever to upper stable position.
Wait for pressure to drop below 200 torr.
Open butterfly valve all the way (handle down).
Wait for pressure to reach 50 torr.

Outside de the main building, on your left when you face IOTA entrance door:

Turn on roots blower (smaller pump).
Wait until pressure goes down to about 2-5 torr.

Vacuum System Shutdown

Inside the main building, next to the dewar pump:

Close butterfly valve.

Outside de the main building, on your left when you face IOTA entrance door:

Turn off roots blower.
Wait at least one minute for roots blower to stop driving air.
Open HOKE valve on Roots Blower input.
Turn off Main Pump.

Inside the main building, next to the dewar pump:

Open solenoid foreline backfill valve.
If you want to refill the tank with air, open backfill valve on main tank. We usually do not do it.

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