How to use the LIGO Leak Checker

Initial Setup

Put the exhuast tubing as far away from the vacuum system as possible, preferably outside the laser curtains and door

Plug in the leaker checker power cord into a "dirty" wall outlet

Turn the leak checker on by flipping power switch and let the leak checker go through diagnostics until “stand-by”

Hit vent on the leak checker (3rd button down on left) and then close vent (same button)

Disconnect the KF25 blank and connect the KF25 hose to the leak checker and to the valve on the vacuum system

Hit the large "start" button to pump on tube. The pressure should get to 7.6E-3 Torr (or somehow lower) and the top of the screen should have "fine detection". The leak rate should be close to 1E-10 Torr L/s, but it could be ~1E-8 Torr L/s)

Once these conditions are met, slowly open the valve to the main chamber body

If possible, valve off the turbo & ion pumps so that the leak checker is the only pump operating. Turn off sensitive equipment (like the RGA at 1.0E-4 Torr) if the pressure rises too far

Introducing Helium

Open up main tank valve

Adjust the upstream of the two black valves

Open up smaller valve on regulator to see a bit of gas

Twist joint at end of hose to release helium

A small puddle of isopropanol can let you tell if helium is coming out

Slowly spray the helium next to various seals on the vacuum chamber. Helium tends to rise so start high, but note the clean room blowers will push the helium down as well.

Wait a few seconds to see if the leak rate rises. If so, try to localize further. Wait for the helium measured to decrease before moving on to new areas.

Stop procedure

Shut helium valves

Close valve from tubing to main body

Hit "stop" button

Wait a few moments and hit "vent" and "close" Note that the hose will expand when venting.

Disconnect hose from vacuum chamber (and leak checker if putting away long term)

Turn off leak checker