When: 30/Sep./2022
Who: Kimura, Yasui, M. Takahashi, Hirata, Fabian and Ueda (SKS)
Task:
We performed vacuum leak test on the BS and found one large lleakage.

The positon of leakage was hermetic sealed connector with leak level of ~8.0x10^-8 Pam^3/s.

Please see attached photos.

The leak was repaired by injecting acetone.

The amount of leakage after injection was less than 1x10^-12 Pam^3/s.

After lunch, we checked the leakage and found no change in the level.

This repair method is a temporary measure. This leakage is likely to reoccur and replacement of the hermetic seals should be considered.

Based on this, it was determined that the leak had been repaired.

Similar leaks had occurred three times (klog20981, klog20325 and klog19536 ) in the past.

Cases of Klog's 20981 and   20325 have been  replaced the harmetic sealed connectors.

I, KIMURA, felt that care should be taken in handling the hermetic seals.

The mass of the connecting cables appear to be loaded onto  the hermetic sealed connectors.

I presume this is the cause of the leakage at the connector.

The support method needs to be changed so that the mass of the connecting cables are not loaded onto the hermetic sealed connectors.