RADIATION MEASUREMENT DEVICE

A radiation monitoring device includes: a scintillator emitting fluorescence upon absorption of radiation, a photo-multiplier tube converting the fluorescence into an electron pulse, a preamplifier converting the electron pulse into an analog voltage pulse, a pulse amplifier amplifying the analog voltage based on a gain control value, a dose rate measurement part measuring a dose rate based on an output of the pulse amplifier, an average half width measurement part, measuring a half width of a voltage pulse, which is among the outputs of the pulse amplifier and has a wave height larger than a preset value, and processing a predetermined number of measured data on the half widths to calculate a half width deviation, a gain control part receiving the half width deviation from the average half width measurement part, and determining the gain control value using a table, which lists relations between half widths and temperature calibration factors.