I measured residual gas pressure inside of IYC with Q-mass during re-cooling of IYC payload.
Please confirm attached three graphs.
The conditions during measurements are as follows;
IYC BS side inside pressure=1.1 x 10^-6 Pa
IYC arm side inside pressure=3.2 x 10^-6 Pa
Yfa (duct shield cryo-cooler arm side) inside pressure=4.9 x 10^-6 Pa
IYC inside pressure=2.5x 10^-6 Pa
8 K shield temp:
Top=18.6 K
TM=73.3 K
Condition of view-ports;
There are "NO' frosting on the surface of view ports visually after stoping cryocooler.
See Tomaru-san's K-log on 06/Feb/2021.
From the measurement, it was confirmed that the the pressure drop of the residual gas due to the re-cooling of the inner shield was not effected.
