I tried to measure the residual gas molecules by a mass spectrometer.
The Q-mass could be operated by a front panel, and the pressure was 3.0*10^-5 Pa, 7.8*10^-7 Pa for H2o and N2 respectively.

Hoever, I could not connect to PC, and could not do degas.
This Q-mass needs degas but in order to do that, the connection to PC is needed...

I will ask the company.