| 摘要 |
PROBLEM TO BE SOLVED: To provide a portable and small radon concentration measuring instrument capable of continuously monitoring radon concentration in underground atmosphere for a long period by embedding underground. SOLUTION: A radon detector forms, at the tip end of a cylindrical vessel 1 inside, a chamber 2 detecting radon and an air-water separation film 4 transmitting only air is arranged. On the inside wall of the chamber 2, a thin film scintillator 5 is arranged. Along the inner part of the vessel 1 cylinder, an optical fiber 6 is arranged as an optical guide transmitting the emission of scintillator 5 due toα-ray emitted from radon or a daughter nuclide of radon backward a space 2. At the end of the optical fiber 6, a photo multiplier tube (PMT) 7 is arranged adjacent to the inner space 2 as a photodetector, which is connected to a data acquisition system for analyzing radon concentration described later and thus radon concentration measuring instrument is constituted. COPYRIGHT: (C)2004,JPO
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