Patent ID: 8315836

Claim:
A radiation measuring device, comprising: a pulse height discrimination portion that receives an input of an analog signal pulse as a detection result of radiation by a radiation detector and outputs a digital pulse when the analog signal pulse satisfies a predetermined pulse height condition; a count portion that receives an input of the digital pulse and outputs a count value by counting the digital pulse in a fixed cycle; an adder-subtractor accumulation portion that receives an addition input of the digital pulse outputted from the pulse height discrimination portion and a subtraction input of a feedback pulse and outputs a result as an integrated value; an accumulation control portion that performs control in such a manner that the digital pulse and the feedback pulse inputted into the adder-subtractor accumulation portion are counted with a weight on the basis of a standard deviation; a pulse generation portion that outputs a pulse having a repetition frequency corresponding to the integrated value to the adder-subtractor accumulation portion upon input of the integrated value as the feedback pulse; and a computing portion that receives an input of a count value of the count portion and an input of the integrated value of the adder-subtractor accumulation portion in a fixed cycle, finds a first count rate on the basis of the count value of the count portion and the integrated value of the adder-subtractor accumulation portion and a second count rate on the basis of the integrated value of the adder-subtractor accumulation portion, and compares the first count rate with the second count rate to make and output a diagnosis on an accuracy of the adder-subtractor accumulation portion.