Abstract: There is a need for routine radon screening of homes, especially in states which require radon screening prior to sale, that are compact, inexpensive, do not require a professional to operate, and which, further, can yield a significant measurement in hours or minutes rather than days. The present invention provides for a combination of control of entry of radon by adjusting the separation between and the area of a multi-element shell, into a measuring chamber while excluding light and extraneous particulate material. This permits a design with a faster response time and also provides for the accurate measurement of individual scintillation events in a scintillating medium by imaging of, and discriminating specific energy levels related to the known energies of alpha particles emitted in the decay pathway of radon. This discrimination functions as an alpha-particle spectrometer and will. Thus, other background radioactive disintegrations or cosmic ray events will be filtered out of the signal.

Abstract: There is a need for routine radon screening of homes, especially in states which require radon screening prior to sale, that are compact, inexpensive, do not require a professional to operate, and which, further, can yield a significant measurement in hours or minutes rather than days. The present invention provides for a combination of control of entry of radon by adjusting the separation between and the area of a multi-element shell, into a measuring chamber while excluding light and extraneous particulate material. This permits a design with a faster response time and also provides for the accurate measurement of individual scintillation events in a scintillating medium by imaging of, and discriminating specific energy levels related to the known energies of alpha particles emitted in the decay pathway of radon. This discrimination functions as an alpha-particle spectrometer and will. Thus, other background radioactive disintegrations or cosmic ray events will be filtered out of the signal.