A Simultaneous Measurement Method Of Radon And Thoron Concentrations By Using A Scintillation Cell

A simultaneous measurement method of radon and thoron concentrations by using a scintillation cell was developed. The method realizes discrimination of radon and thoron each other on the difference of their half-lives. It consists of three steps: The first step is that 5 minutes count is done for the determination of thoron concentration after circulating for 5 minutes when the fresh radon and thoron mixed gas flows through scintillation cell with the flow rate of 3.0 L.min(-1). The second step is that 5 minutes count is done for the determination of radon concentration after waiting for 15 minutes when the pump is stopped. The third step is the calculation of radon and thoron concentrations. There are two calculation methods, they are the simultaneous calculation and the correctional calculation of the influence of longer life thoron daughters to radon concentration. The simultaneous measurement of radon and thoron reference concentrations in the thoron chamber can be done in one hour by using the method.