| 摘要 |
<p>In EMI scanners it is desirable to substantially reduce the time required for measuring. Therefore, it is necessary that the radiation source/ radiation detector system is not stopped and subsequently accelerated again for each measurement of group of measurements. A system which continuously moves, preferably at a uniform speed, is very attractive. The invention enables the evaluation of the output signals of the radiation detectors derived from such a continuously rotating system with continuously switchedon source. To this end, the output signal of each radiation detector is conducted via a low-pass filter and applied to a sample-and-hold circuit having a sampling frequency which is about twice as high as the limit frequency of the low-pass filter. Moreover, results can be obtained which are more accurate than those obtained with known scanners with discontinuous movement or a flashing radiation source.</p> |
