I pumped down the cryostat and turned on the Q-mass.
The LED lamp next to "POWER" turned on, though that of "Pa" did not.
It seems that this Q-mass may not be used anymore.

Furthermore, in order to degas the Q-mass, we need to pump down below 10^-4 Pa, though it cannot reach below 6*10^-4 Pa...
I gave up the measurement.