The interlock system closed GVbsx and GVbsy around 11 AM. As GV closed, the pressure at the center area (IMC- BS- OMC) increased, and the pressure in IXC and IYC decreased.
The reason for the activation of the interlock system is unknown. It is possible that there was a malfunction of the vacuum gauge used for the monitor or a pressure increase due to leaks, etc.
To open GVbsx and GVbsy, we will monitor the pressure change and Qmass measurement until noon tomorrow and judge the results.
Because Kimura-san started two TMPs/Dry pumps near BS(Kimura-san? will report) for the pumping in the MICH area, I,
- turned off two Sunrise heaters near SR2+X side and PR3-Y side,
- changed the target temp of the precision cooler near SR2 from 20.00 to 19.00.
to adjust the temperature around BS at around 18:00.
Owing to two TMP operations near BS, the vacuum level at the MICH area seemed to decrease and reached the equilibrium pressure? This means that more TMPs operation will result in the lower pressure.
The pressure difference at BS before and after closing GVs is just 2 times.
So can we open GVs? or shall we temporally operate all TMPs in the MICH area and wait to reach the same vacuum level?
Because TMPs will be off, I recovered the target temp for the precision cooler from 19 to 20 and turned off two Sunrise heaters around 14:00.
[Kimura and Yasui]
GVbsx and GVbsy were opened in the following steps.
2Step 1:
13:45 Disabled the enable/disable switch in the GVbsx and GVbsy interlock device.
Step 2
13:48 Opened GVbsy and closed the GVs of the TMP.
BS-CC-10 pressure was 1.4 x 10^-5 Pa.
Step 3
13:50 Opened GVbsx and closed the GVs of the TMP.
BS-CC-10 pressure was 1.4 x 10^-5 Pa.
Results of the partial pressure measurement are as follows;
BS | IXC | IYC | |
| Time | 14:03 | 14:09 | 14:05 |
| T.P. (Pa) | 1.45 x 10^-5 | 4.15 x 10^-6 | 5.73 x 10^-6 |
| H2 (Pa) | 2.00 x 10^-6 | 1.68 x 10^-6 | 2.27 x 10^-6 |
| H2O (Pa) | 2.09 x 10^-6 | 1.16 x 10^-6 | 1.62 x 10^-6 |
| N2 (Pa) | 5.54 x 10^-7 | 5.61 x 10^-7 | 7.03 x 10^-7 |
| O2 (Pa) | 3.54 x 10^-7 | 2.07 x 10^-7 | 2.48 x 10^-7 |
[kimura and Yasu]
We turned off two TMPs and two dry-pumps at 14:50.
[Kimura and Yasui]
BS CC-10 pressure reached 7.5 x 10^-6 (Pa) at 16:10.
The threshold of the CC-10 contact output was then set to (7.5 + 0.5) x 10^-6 (Pa) of 8.0 x 10^-6 (Pa).
After setting, the interlock device was enabled.
Results of the partial pressure measurement at 7:43 on Jan. 11 are as follows;
| Place | BS | BS | IXC | IYC |
| Date | 1/07 | 1/11 | 1/11 | 1/11 |
| Time | 10:45 | 7:43 | 7:39 | 7:44 |
| T.P. (Pa) | 1.28 x 10^-5 | 1.20 x 10^-6 | 4.37 x 10^-6 | 4.62 x 10^-6 |
| H2 (Pa) | 1.42 x 10^-5 | 1.52 x 10^-6 | 1.65 x 10^-6 | 2.01 x 10^-6 |
| H2O (Pa) | 1.57 x 10^-6 | 1.49 x 10^-6 | 1.27 x 10^-6 | 1.22 x 10^-6 |
| N2 (Pa) | 6.18 x 10^-7 | 5.05 x 10^-7 | 6.22 x 10^-7 | 6.04 x 10^-7 |
| O2 (Pa) | 3.04 x 10^-7 | 3.10 x 10^-7 | 2.21 x 10^-7 | 2.03 x 10^-7 |
The partial pressure of the residual gas components were recovered to the level before the interlock device operated and the gate valves closed.