Abstract: There are provided a storage section 220 that stores an output value read out by counting a pulse signal of incident X-rays, by a photon-counting type semiconductor detector; and a calculation section 230 that calculates a count value based on the output value that has been read out, wherein the calculation section 230 uses a model in which an apparent time constant of the pulse signal monotonously decreases against increase in pulse detection ratio with respect to exposure. According to such a model, the corresponding apparent time constant is able to be obtained even in any higher count rate. As a result of this, reduced can be the influence of count loss even on the count rate that has not been able to be covered by the conventional method.

Abstract: There are provided a storage section 220 that stores an output value read out by counting a pulse signal of incident X-rays, by a photon-counting type semiconductor detector; and a calculation section 230 that calculates a count value based on the output value that has been read out, wherein the calculation section 230 uses a model in which an apparent time constant of the pulse signal monotonously decreases against increase in pulse detection ratio with respect to exposure. According to such a model, the corresponding apparent time constant is able to be obtained even in any higher count rate. As a result of this, reduced can be the influence of count loss even on the count rate that has not been able to be covered by the conventional method.