| 摘要 |
PURPOSE:To make it possible to monitor the degree of vacuum at a low cost, by emitting light from the outside of a vacuum shielding device, and detecting the reflected light from the surface of a gas absorbing material. CONSTITUTION:A gas absorbing material 9 is provided in a vacuum container. Light from a light source 12 is projected on the gas absorbing material 9 through a semitransparent mirror 11 and an optical fiber 10. The reflected light is received by a light detector 14 through the optical fiber 10 and the semitransparent mirror 11. Meanwhile, part of the incident light from the light source 12 is reflected by the semitransparent mirror 11 and received by a detector 13. The ratio between the outputs of the light detectors 13 and 14 is measured by a comparator 15, and the degree of vacuum in the vacuum container is monitored. |
