| 摘要 |
PURPOSE:To easily detect a beta-ray emitting nucleide having a power of energy without using a high degree of technology by measuring a beta-ray emitting gas to be detected, with the use of a semiconductor radioactive ray detector adapted to detect beta-rays having a low power of energy, after the beta-ray emitting gas permeates under a membrane separating process. CONSTITUTION:A plurality of semiconductor type beta-ray detectors are arranged in series on the posterior stage of a separating membrane permeated by a beta-ray emitting gas to be measured and provided in an inflow part in which radioactive fluid flows. Semiconductor detecting elements 3, 4 which become sensitive only to beta-rays having a low power of energy are applied on the inner surface of the housing 3 of each of the detectors, facing together so as to extract beta-ray detection signals by means of electrodes 7, 7'. The detection signals are transmitted through coupling capacitors 10, 10' to preamplifiers 11, 11 and linear amplifiers 12, 12' so as to be amplified. An anticoincidence circuit 13 is connected thereto on the posterior stage thereof, and is then connected thereto with a radioactivity computing means 14 which is then connected to a display 14 for indicating thereon a detected value. The circuit 13 delivers beta-rays only when a unit output is present, so as to largely eliminate affection by background radioactive rays.
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