Radioactive gas monitor

摘要

A shield has a detector installing hole having a central axis orthogonal to a central axis of a detection tube. A radiation sensor of a columnar scintillation detector to which a low concentration side measurement range within all required measurement ranges is allocated is arranged inside the detector installing hole. An ionization chamber to which a high concentration side measurement range is allocated is arranged side by side in parallel with the detection tube. The measurement range of the columnar scintillation detector and the measurement range of the ionization chamber are adjusted so as to be overlapped with each other.

主权项

1. A radioactive gas monitor comprising:
a detection unit that detects radiation emitted from radioactive nuclides contained in sample gas; and a measurement unit that processes a signal transmitted from the detection unit and outputs an engineering value corresponding to radioactive concentration, wherein the detection unit has a detection tube through which the sample gas flows, a first detector to which a first concentration measurement range within all required measurement ranges of radiation is allocated, a second detector to which a second concentration measurement range within all required measurement ranges of radiation is allocated, wherein concentrations in the second concentration measurement range are higher than concentrations in the first concentration measurement range, and a shield which shields the detection tube, the first detector, and the second detector from environmental radiation, the measurement unit has a first measurement unit which processes a signal transmitted from the first detector and a second measurement unit which processes a signal transmitted from the second detector, the shield has at least one detector installing hole having a central axis orthogonal to a central axis of the detection tube, and at least the first detector between the first detector and the second detector is arranged inside the detector installing hole, and an inner diameter of the detection tube and a relative position between the detection tube and the first detector are determined so that the measurement range of the first detector and the measurement range of the second detector are overlapped with each other.