| 摘要 |
PURPOSE:To enable highly accurate analysis by using a proportional counter tube as an X-ray detector to detect a shift of a peak position of X-rays whose existence and position of the energy peak contained in secondary X-rays are known and by controlling applied voltage of the proportional counter tube based on the detection results. CONSTITUTION:A peak position shift detection unit 13 comprises a digital window comparator 14, a digital subtractor 15, a D-A converter 16 and an integrator 17 which are connected in series. An output of the D-A converter 10 is input to the comparator 14, and an output of the integrator 17 is input to a control unit of a high voltage power source 8 for driving a proportional counter tube 4. The comparator 14 determines whether or not information X regarding scattered X-rays 6 as X-rays whose existence and position of the energy peak contained in secondary X-rays 7 are known is in a predetermined energy range, while the subtractor 15 calculates difference between the information X and the peak energy of the X-rays 6 to output the subtraction output. This output is converted by the converter 16 and integrated by the integrator 17. |
