Relative dose rates from the three most common NORMs

[ColoRad-o]

As y'all know, aerial gamma surveys can map out soil concentrations of 232Th and 238U (and their many decay daughters), plus 40K. And of course, so can we. As a follow-up to some of my recent postings, I'm enclosing the relative dose rates (as a function of gamma energy) for these three. These should be regarded as semi-quantitative, since they depend on efficiency data for a 2"x2" NaI:Tl detector which undoubtedly differs in detail from the one I have. (I have only a small carton of KCl salt substitute as a 40K source, so had to subtract background from its spectrum, hence the noise.). Not sure who might find these useful.