| 摘要 |
PURPOSE:To discriminate the propriety of a vacuum degree in a vacuum container in safety and with high precision by fitting a passive part, consisting of an electrooptic effect element and a prism, to the vacuum container wherein an electric field varies with the vacuum degree. CONSTITUTION:A passive part 1 has an electrooptic effect element 3 and a rectangular prism 4 and is fitted detachably to the outside surface of the vacuum container of a vacuum electric apparatus wherein an electric field varies with a vacuum degree. Light arriving from a light source 5 through a polarizer 6 is made incident to the electrooptical effect element 3 to vary the angle of its plane of polarization by the electric field E varying with the vacuum degree, and the light enters the prism 4, where it is reflected in the incident direction. The angle of the plane of polarization of the emitted light is varied again by the electrooptic effect element 3 and the light is made incident to the analyzer 7 of a monitoring part 2. The polarized light made incident to the analyzer 7 strikes a photoelectric conversion part 8 to discriminate the vacuum degree by a discrimination part 9 by using variations of an electric signal at the photoelectric conversion part 8. |
