Who:Kimura, M. Takahashi and Sawada (Hokuto)
Task:
A vacuum leak test was carried out between the X-arm gate valve and the BRT gate valve in the EXC area, again.
It was confirmed that there was very large vacuum leak of ~1 x 10^-9 Pam^3/s around the EXV chamber.
Pleas see attached first and second photos from display on helium leak detector.
Candidate leak locations are as follows;
#1: Helium gas entered through the hole for the push screw on the EXV horizontal flange and reached the leak occurring at the elastomer seal.
#2: Cracks in the ceramic sealing area of the hermetic seal connector.
Pleas see attached third photo.
Of the above two candidate locations, we could not identify which one was the location of the leak.
We plan to conduct another leak test this Friday (21/Jan./2022) to determine the location of the leak.
Who:Kimura, Tomaru, Yasui and Yano
Task:
We fixed very large vacuum leak place at the EXV chamber.
The place was on D-sub type hermetic sealed connector .
Pleas see attached photos.
The leak level was 3.0 x 10^-7 Pam^3/s.
We are assuming the reason of leak was crack in the ceramic or pin hole of sealing between pin and the ceramic.
We will discuss how to repair it.
Who: Kimura, M. Takahashi, Yasui and Sawada (Hokuto)
Task:
We found very small vacuum leak place at new vacuum pump near EXT chamber.
The place was on connection flange between tees and Ion pump.
The leak level was 5.0 x 10^-11 Pam^3/s.
Pleas see attached photos.
We are assuming the reason of leak was tilting of the Ion pump by its weight.
We asked Mirapro how to repair it.
2022/02/10
We repaired the vacuum leakage at the new vacuum pump near EXT chamber.
No leak test yet.