Because the old ion gauge for x-ray gun did not work stably, I ordered a new ion gauge from MDC. The old gause was replaced as soon as I got this new gauge. The vacuum reached around 3x10^-5 Torr before I left the lab.
For LLG-TWIN, I have to change the gases twice to make sure the timing trigger steadily. The laser energy would be decreased in a couple of minutes after first gas filling, then it's hard to synchronize the seed beam and the TWIN. After evacuating the chamber and refilling the gases, the TWIN became better.