[Kimura and Ueda (SKS) ]
On the morning of April 17, a vacuum leak test was performed on the closed flanges around IXC and IXA.
The vacuum leak test results showed a large leak of more than 3.9 x10^-9 Pam^3/s at the +Y side flange of the cross tube.
Since this leak affects the cooling of the mirror, it is necessary to repair the leak by pressurizing the vacuum chamber to atmospheric pressure.
High purity air with a low dew point was arranged for pressurization.