| 摘要 |
PROBLEM TO BE SOLVED: To provide an X-ray position detector which enables detecting of the movement of a fan beam at a high accuracy. SOLUTION: A signal ratio indicating a focus position generated by an damper 108 and a detector cell 100 is highly sensitive to a focus position to facilitate the generation of a high quality image from projection data. Even if the cell 100 overflows completely, the intensity of a signal from the cell changes according to matching between a focus 50 and a slot 112, making a focus movement detector 104 effective for detecting the movement of a fan beam. Dampers 108 and 110 are arranged covering the detecting surfaces of the cells 100 and 102. The slots 112 and 114 extends piercing the dampers 108 and 110 so that at least parts of the cells 100 and 102 communicate with the X-ray beams 16. The slots are so arranged that the signal from the cell 100 has the maximum X-ray response at one extreme end position 116 while the signal from the cell 102 has the maximum X-ray response at the other extreme end position 118. |
