MINIATURE PERSONAL AND AREA RADON AND THORON MONITOR

摘要

The present invention relates to a radon Rn222 and Rn222 thoron radiation monitor (20) that uses alpha-track detection film in multiple, separate chambers (11, 12, 13) to detect radiation. The invention further describes use of different diffusion barriers in each of the chambers (11, 12, 13) to allow for signal differentiation between the chambers (11, 12, 13). The signal differentiation allows for differentiation between the levels of thoron and radon in the atmosphere tested. In a preferred embodiment of the invention, the radiation monitor (20) has three or four separate chambers (11, 12, 13), each with an electrically conductive housing and a cap (71, 72, 73) with at least one opening (32) to permit entry of ambient air. Inside each of the housings is an alpha-track detecting film, such as a solid-state nuclear track detector "SSNTD", with a thin electrically conducting cover (30). In one or more of the chambers (11, 12, 13) is a diffusion barrier and seal placed within the housing to generally isolate the detecting film from thoron radiation in the housing.