Loading samples

Checklist for operation of load lock

1. Close all valves connected to the turbo pump: to exchangeable ports, to gas line and to load lock.

Important! When closing the valves to the turbo pump check and keep in mind what else is pumped with the same pump (e.g. bakeout of exchangeable evaporators). It will not be possible to open these valves for about an hour while load lock is being pumped.

2. Make sure that the valve between load lock and preparation chamber is fully closed.

3. Stop turbo pump by pressing on-off button. Leave the prepump (membrane pump) running.

4. Close the valve between the turbo pump and load lock (VLL).

5. Check the pressure of N2 bottle inside the cabinet. The pressure of $N_2$ should be positive and non-zero (*).

6. Loosen the screw on the load lock door. Vent load lock by opening the $N_2$ valve, at some point door should open by itself. Leave the $N_2$ valve open to keep some gas flow.

7. Insert your samples in the load lock transfer rod (using e.g. long pliers). Rotate samples hook-up!

8. Close the $N_2$ valve properly.

9. Make sure the viton ring on the load lock door is clean and then close it.

10. Check that turbo pump has stopped completely. Slowly open the valve between pump and load lock. Air should be quickly pumped by the working membrane pump.

11. Wait for pressure to reach 5 mbar (**), and then start turbo pump.

12. Wait for pressure to reach at least$5*10^{-7}$mbar (usually after ~60 minutes).

Rule of thumb: pressure in the preparation chamber after opening the load lock valve will be ~50 times better, i.e. $1*10^{-8}$ mbar.

13. Close the VLL, and open the valve to the preparation chamber.

14. Check that nothing is on the way of the load lock’s rod, and then move the rod to the chamber.

15. Transfer your sample to the chamber using the wobble stick, retract the rod, and close the valve between chamber and load lock.

16. If you want later to remove your sample from the chamber, then do not forget to open the VLL, to leave the load lock pumping.

17. Check what else should be pumped and don't forget to re-open the respective valves that were closed at the step #1.

18. Enjoy the experiments!

Troubleshooting:

* If pressure in $N_2$ bottle is 0 or negative.

Check that the valve on top of the gas bottle is open. If nothing helps and user support is out of reach, you can close the $N_2$valve and vent load lock to air by opening the door by force (e.g. using a screwdriver).

** If pressure does not reach 5 mbar after few minutes, check that the door and $N_2$ valve are properly closed.