| 摘要 |
<p>An inbuilt aid is used for the assessment of the amount of use a high-voltage cathode ray tube has had. It uses a material within the tube which is visible from outside it, which gradually changes colour when subjected to the secondary radiation rpesent in such tubes. The method is applicable to colour television tubes, X ray tubes, orielograph tubes, and the like where the high voltages present generate a certain amount of secondary, usually X-ray radiation. A small sample of the detection material, typically phototropic glass, is mounted in the tube, near the shadow mask in the case of television tubes, so that it is visible from some point outside the tube. This gradually changes colour and indicates roughly the number of hours for which the tube has been used.</p> |
