JPS5728277A - Radiation detector - Google Patents

Abstract

PURPOSE:To enable the measurement to be performed regardless of the variation in measuring states, by providing a scintillator in an air tight chamber to which radioactive gas is introduced and a pressure reduced chamber which is provided with a radioactive substance or a radiation transmitting wall and wherein pressure is arbitrarily reduced. CONSTITUTION:An air tight chamber 10, wherein the radioactive gas is introduced, comprises a case 12. One end of the case 12 is opened, and outlet and inlet ports 18 and 16 for the gas are provided in the side walls. The pressure reduced chamber 20 is connected to the opening part via the radioactive substance or the radiation transmitting wall 14. Furthermore, an optical conductor plate 22 is air-tightly fixed. Air inlet and outlet ports 24 and 26 are provided in the pressure reduced chamber 20, and the pressure is reduced to an arbitrary pressure. The scintillator 28 is fixed to the vicinity of the optical conductor plate 22. When radioactive gas, e.g., tritium is introduced, the radiation is introduced to the pressure reduced chamber 20 from the transmitting wall. Since the pressure is low, energy loss is small, and the scintillator 28 is sufficiently lit corresponding to the amount of radiation. The light passes the optical conductor plate 22 and enters the light receiving plane of a photoelectric multiplying tube 30, and the photoelectric conversion is performed. In this constitution, the detection can be performed regardless of the variation in the measuring conditions.