GAMMA DISTRIBUTION AND HOUSE 222Rn MEASUREMENTS

A problem exists in the meaning and use of the term "unattached fraction" to describe the highly diffusive portion of the airborne radon progeny. The term was originally developed to aid in lung dosimetry but now that more detailed size measurements can be made, there are ambiguities in its definition between a physical size basis and a dosimetric definition. Some possible ways to resolve these ambiguities are presented and discussed. It is suggested that the term only be used in the context of complete size information rather than as the conventional operationally defined term.