[Kimura, M.Takahashi and Sawada]
We replaced the failed Ref 3 (P-55) compressor with a spare and restarted cooling of the inner radiation shield.
We conducted a simple inspection by irradiating a black light on the discharge side connection of the removed compressor and the connection piping.
As a result, luminescence indicating oil traces were observed at the gas contact area. Therefore, the connection piping and filter from Ref 2 (P-54) compressor were converted to Ref 3 (P-55).
The connecting piping and filter need to be newly replaced.
Currently, there are a total of five cryo-coolers in operation at EXC: two duct shielded cryo-coolers, Ref1 (P-53) for radiation shield , Ref3 (P-55)for radiation shield, and Ref4 (P-56) for payload.