摘要 |
<p>A detector for detecting conductive substances mixed in a string-like material sensitively, which is a cylindrical microwave cavity resonator (1) comprising a peripheral part (9) and two circular plates (10) covering the ends of the peripheral part. At least one of the circular plates has a cylindrical protruding part (4) at its center. In the peripheral part, an antenna (5) for the generation of discharge is provided. In the protruding part (4) a detection means (6) for discharge is provided. Paths (3, 8) or a notched part (7) for the string-like material to be measured which passes through a high electric field formed by the protruding parts and penetrate the cylindrical microwave cavity resonator are provided. When the string-like material containing very small metals passes through the protruding part of the microwave cavity resonator oscillating at a fixed frequency, discharges are generated by the strong electric fields concentrated on the very small metals. Since sounds, light, and electromagnetic waves are generated at this time, the very small metals can be detected sensitively with discharge detecting means such as a microphone, a photodetector and an antenna.</p> |