| 摘要 |
An instrument for measuring the thickness of layers by means of radiation emitted from radio-active nucleides which interact with material of the layer and are then absolved by a radiation detector. A sighting mechanism determines the area of the layer to be irradiated and a diaphragm is interposed between the radio-active nucleide and the layer to define this area. A radiation detector on a supporting device can be moved into and out of a measuring position relative to this area. The sighting mechanism |
