[Takahashi-san, Tanioka]

We did vacuum test of cryostat at ATC using scroll pump and turbo pump.
The procedure was as follows:

1. Close the chamber (without 4K shield temporary).
2. Confirmed all the valve were closed and turned on the scroll pump.
3. Opened the valve.
4. Then the pressure level was down to 3.0*10 Pa.
   However, it increased and reached about 5.5*10 Pa.
   This was due to the residual water molecules inside the chamber and it was solved by opening gas ballast of scroll pump.
5. After some iterations, the pressure level reached about 10 Pa.
   We turned on the turbo pump and the pressure level decreased less than 10^-1 Pa.

So it seems that there is no huge leakage, which was good thing.
However, after a few minutes turbo pump run, the scroll pump was turned off for some reasons.
Unfortunately I could not see what happened since I went to bathroom.
We tried to recover, but the scroll pump did not work even the power indicator did not iluminate...
One possibility is that fuse blown.
We will investigate.