| 摘要 |
PROBLEM TO BE SOLVED: To exactly measure radiation deterioration characteristic by irradiating only a deterioration measuring object x-ray detector of a multiple stage X-ray detector with X-ray given times, then irradiating the detector together with an other detectors with X-ray, and by comparing the output data observed an each of detectors at a given number of times and a standard data to obtain the irradiation deterioration characteristic. SOLUTION: Firstly sensitivity of a two stage detector array 60 is made to be recovered by not performing X-ray irradiation for a considerable length of time. Then, output data of detector array D1 and D2 in the first operation is measured. Successively X-ray beam Xr irradiates only detector array D1, air scanning is conducted [m times (m equals to or is larger than 1)], then both detectors D1 and D2 are irradiated with X-ray beam Xr and outputs of both detectors D1 and D2 at nth times (n equals to m plus 2) are acquired. Thus fluctuation ratio of detector array D1 and standard fluctuation ratio of detector array D2 are calculated and the radiation deterioration rate of the detector array D1 is obtained based on the above results.
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