Reports until 13:23, Wednesday 30 April 2025
Vacuum Systems General (RbQ)
Daniel Grass - posted 13:23, Wednesday 30 April 2025 - last comment - 23:13, Wednesday 30 April 2025(12295)
RbQ Vacuum Chamber Pumps Turned On

I plugged in RbQ Vacuum Chamber turbo controller into the wall outlet. After warming up, the pressure was "over pressure". I enabled soft start, hit show decrease speed, changed the gas load to air (I don't think this does anything), and changed the pressure units to Torr. I plugged in scroll into the wall outlet and turned it on at 11:57 AM. It starting pumping after 35 seconds, and the pressure gauge showed numerical readings a few seconds after that. I put the interlock bypass D-Sub into the turbo controller and started turbo at 8E-2 Torr, 6.5 minutes after turning on scroll. While in the soft start, the turbo pump drew up to 95W, around 4E-5 Torr 11.5 total minutes in and 2E-5 13.5 total minutes in. After 18 total minutes, the pressure was 1.6E-5 Torr (2x worse than LFC, 10x better than Dewer, all 12 minutes after starting the turbo), 16 W drawn (LFC 10W, Dewer 16W, all 12 minutes after starting the turbo), 1167 Hz pump speed (this is manually set). The pressure was 7.2E-6 at 1:11 PM. I think we can get below 1E-6 Torr, but this is still too high for an Rb MOT, which should be near 1E-8 Torr (the Berkeley class lab operates aaround 4E-8 Torr). The cube baseline pressure is 1E-7 Torr. We probably need to leak check.

Comments related to this report
Daniel Grass - 23:13, Wednesday 30 April 2025 (12297)
Time Pressure (1E-6 Torr)
1:59 5.5
2:45 4.7
3:26 4.1
3:54 3.8
4:17 3.9
4:26 3.8
10:48 2.6

By eye, I think we will get to 1-2E-6 Torr. I will get the leak checker tomorrow and hope to use it soon.