Kimura, Yasui, Uchiyama
From 5 AM, the vacuum pressure in IX was rapidly increased due to the temperature increase of the IX Ref1 cryocooler. The interlock system closed GVbsx and GVbsy at 8 AM.
We stopped 3 ion pumps (#5, #7, #29) and restarted 4 TMPs (#5, #7, #3, #13) to protect the ion pumps at around 9 AM.
During this vacuum pressure enhancement, N2, O2, CO, and Ar were evaporated from the inner shield of IXC.
[Kimura and Yasui]
We attached trend graph by Q-mass for IXC.
Kimura, Yasui, Ushiba, Uchiyama
At 3 PM, situations around IXC were
・With Qmass of IXC, the total pressure in IXC and part-pressure, such as N2, also showed a tendency to decrease,
・The total pressure in IXC was about 2E-5Pa, and there was no significant difference from the pressure around the BS area (1.3E-5Pa),
・Even if GVbsx and GVbsy are opened, no serious problem with the ion pumps,
・Both IXC and IYC have an inner shield of 30K or more. → There is no adsorption of N2, O2, etc. released by IXC.
We determined to open GVbsx and GVbsy, and we did it at 3:20 PM.
Finally, we turned on 3 ion pumps (#5, #7, #29), which we turned off this morning. We also turned off 2 TMPs (#5, #7) around IXC.
2 TMPs (#3, #13) at BS+X and BS+Y were kept operation.
Attached is a trend graph of this morning's IXC and BS Q-mass measurements.
The partial pressure distribution seems to have almost returned to the level prior to the Ref1 temperature rise.
Uchiyama
I shut down 2 TMPs (#3, #13) around BS at 10:30.
