Leak Checking

NTS, 4/24/2015, NTS Apr 2016.

To be done once a chamber has passed 2e-7 torr and before moving a cell in a transit case, or cleaning out and taking down a glovebag.

Note: Turning on the RGA above 2e-7 can damage it because they are weak and need more vegetables.

List of gases by atomic mass: Leakchecking (RGA)

Opening the He tank

1. Open out to in

2. You do this so you don't recirculate gas in the line back into the cleaner parts, e.g. the tank

3. Open the sprayer all the way, in the static configuration

4. Open the plastic post-regulator valve

5. Open the regulator valve (Opens to the right)

6. Open the He tank

7. Adjust regulator as needed to get proper airflow and remove the sprayer from the static configuration

8. Check the airflow by spraying He at your neck or wrist (do not point at yourself til the gas flow is on and reasonable)

RGA and Software

1. Turn on the RGA hard switch (it should've been off for system venting)

2. Open a new RGA scan window

3. Turn on the RGA from the software: COM port, filament, electron multiplier

4. Put the RGA into leak test mode

5. Turn on the audible alarm, under Utilities [?]

6. Have someone monitor the leak check graph

Leak Check

1. Pass the sprayer into the glovebag

2. He is lighter than air, so start at the top of the area or flange/s you're checking

3. Hold down the sprayer lever and perform the leakchecking

4. Check the flanges, any mini-conflat, all feedthroughs (carefully), etc.

5. If no leak, remove sprayer from the glovebag and coil back up

6. If there's a leak, go to Leak Section below

Closing the He tank

1. Close out to in

2. Close the sprayer

3. Close the plastic post-regulator valve

4. Close the regulator (closes to the left/CCW)

5. Close the He tank

Leak

1. Patiently determine where the leak is

   1. The He pressure will rise pretty quickly and keep going up while the sprayer is spraying near the leak

   2. He molecules rises

2. If you're having trouble finding a leak, but there is one, consider that it might be a virtual leak, or maybe some valve or piece got cracked opened or moved

3. Use the mini-bagging or trash-bagging method to find the leak (used to target where the He goes, pinning down the location you're testing)

   1. Mini-bagging: cut and tape mini bags using the plastic roll and caution tape, then affix and seal around suspected leaks. Poke in the He sprayer to check for a leak.

   2. Trash-bagging: You really don't know where the leak is, so you want a big bag to check certain areas at a time. Go get proper size trash bag, and affix and seal around your first test area. Leak check, and repeat as needed on each area.