RADIATION DETECTOR FOR RADIOACTIVE MATERIAL CONTAINER

摘要

PROBLEM TO BE SOLVED: To provide a radiation detector which can quickly detect radiations from a radioactive material staining a radioactive material container by providing an annular scintillator which is attached to the lower opening of the case of the detector and can cover the full peripheral edge of the lid of the container and a plurality of photomultipliers arranged in the case. SOLUTION: A radiation detector 21 is provided with an annular scintillator 23 which is attached to the lower opening 22a of a case 22 and can cover the full peripheral edge of the lid 12a of a radioactive material container 12 and a plurality of photomultipliers 24 which are arranged at prescribed intervals in the case 22 in a state where the photomulitplies 24 are faced oppositely to the scintillator 23. The detector 21 is moved to a prescribed position on the upper surface of the lid 12a from a standby position by means of a detector moving means. At the position, the annular scintillator 23 of the detector 23 covers the full peripheral edge of the lid 12a. When the peripheral edge of the lid 12a is stained with a radioactive material, the scintillator 23 emits fluorescence due to the radiations from the radioactive material on the periphery of the lid 12a and the photomultipliers 24 quickly convert the fluorescence into electrons. The does of the radiations is quickly measured from the light emitting quantities of the photomultipliers 24.