Patent ID: 8872108

Claim:
A radiation monitoring apparatus comprising: a radiation monitor which measures radiation; and a testing apparatus which conducts a test for the radiation monitor, wherein the radiation monitor includes a radiation detector, and a measurement section which measures a count rate from a detection signal pulse of the radiation detector, the testing apparatus includes a test pulse generation section which generates a test pulse, and a test pulse control section which controls an oscillation frequency (repetitive frequency) of the test pulse and generates a switching signal for switching a measurement mode and a test mode of the measurement section, and the measurement section includes: a pulse amplifying section which amplifies and waveform-shapes the detection signal pulse; a noise discrimination unit which discriminates and eliminates noise from an output pulse of the pulse amplifying section, to output a digital pulse; an up-down counter in which the digital pulse is inputted to an addition input and a feedback pulse is inputted to a subtraction input, and which outputs an accumulated value obtained by accumulating the differences therebetween; a frequency synthesizing circuit which generates the feedback pulse from the accumulated value; an accumulation control circuit which specifies weighting of counting for the up-down counter; a calculation section which receives the accumulated value and calculates a count rate; input switching means which switches the input of the pulse amplifying section or the addition input and the subtraction input of the up-down counter, by the switching signal from the test pulse control section; and an accumulated value setting circuit which forcibly sets the accumulated value of the up-down counter at a value corresponding to a start count rate, by a set accumulated value signal from the test pulse control section.