| 摘要 |
PURPOSE:To enable a stable determination to be performed even in a consumer appliance field wherein no calibrating radiation source can be handled by performing an energy calibration by using radiation emitted from <40>K contained in a potassium compound in a gamma ray dosimeter using a scintillator. CONSTITUTION:A dosimeter is composed of a potassium compound 1 for calibration, a scintillator 2, a photomultiplier 3, charge quantity detector 4, an integrating memory 5, an arithmetic unit 6, an energy distribution memory 7, an energy distribution and dosage display unit 8 and an input unit 9. Since a sensitivity in conversion to a charge quantity is changed by a change in temperature or the like in the scintillator 2 and the photomultiplier 3, a calibration is conducted as follows: gamma rays from a <40>K isotope contained in natural potassium by 0.01% are detected, the peak value of gamma rays that appear in the memory 5 is obtained and gamma ray energy and the charge quantity are calibrated by using the peak value of gamma rays. To do this, a cursor is set to a peak position displayed on the display unit 8 and a calibrating signal is inputted from the input unit 9 whereby a charge quantity scale is transformed to an energy scale.
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