Inertia in the response of radon monitors introduced by diffusion anti-thoron barriers
The reduction of thoron (220Rn) influence on radon (222Rn) monitors by diffusion barriers may cause some deterioration of the quality of the radon measurements. Therefore, the best compromise has to be found between ensured anti-thoron protection and deterioration of the quality of the radon measurements. In this report, the focus is on the additional inertia in the response introduced by passive diffusion barriers against thoron. The characteristic inertia time introduced by diffusion barriers is theoretically modeled for the levels of thoron interference down to 1%. Experiments were carried out with an active monitor working in diffusion mode, using its built-in diffusion barrier and with an additional diffusion barrier added. The experimental results showed very good correspondence with the estimates based on the theoretical model. In summary, when using passive diffusion barriers against thoron, the greater is the reduction in the thoron interference, the larger is the inertia time in the response of active monitors that are introduced.
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