Abstract
We can detect the indication of failures and prevent equipment from becoming damaged through visually monitoring the state inside cryogenic equipment. We investigated use of a flexible fiberscope as an endoscope. We also investigated use of a web camera owing to its low cost. We selected a flexible fiberscope without the function of remote control because of the lower heat invasion and higher voltage insulation. We set the fiberscope inside the cryogenic equipment using a rubber stopper to hold the vacuum. We confirmed that the inside was observable even for objects cooled to approximately 20 K. As for the web camera, we confirmed that it could be satisfactorily used adjusting the temperature to approximately 200 K under a high magnetic field of 5 T.
