| 摘要 |
<p>Method and instrument for measuring X-ray radiation, for generating a value representative of the radiation in the shape of an electric signal, whereby the radiation at the measurement instance is caught by two photo-electric units (7, 8) each receiving the radiation (9) after its passage through filters (5, 6) having mutually different degrees of absorption. The radiation value is computed on the basis of a ratio between the two generated electric signals. Adaptation of the signal intensity to a processing range is made, which constitutes a lesser part of the total intensity range of the signals generated by the radiation, by means of an amplifier device (6) with a variable degree of amplification, by sensing the signal intensity after the amplifier device. The amplifier device (12, 13, 16) is designed as a pre-amplifier (12, 13) which is maintained at a fixed degree of amplification and is in series therewith, terminal amplifiers (16), which are adjusted in their degrees of amplification in order to give the signals said intensity adapted to the operational range. By varying the signal processing, the method/instrument may be adapted for generation of measurement values correlated to parameters such as kVp, X-ray dose, exposure time and curve-shape.</p> |
