Depth distribution of radionuclides

It has been shown that the measurements obtained using a relatively inexpensive portable gamma detector are capable of determining average activity concentrations (of radionuclides that can be estimated by ganuna spectra) in land areas that are not significantly different from those derived from ex situ measurements. This depends on an assumed model of the depth distributions of radionuclides, and it is likely that some ex situ measurements will be required for this purpose. 

If the depth distributions of radionuclides can be modelled and are considered to be consistent throughout a surveyed area, in situ measurements are therefore capable of producing better precision at lower cost than an ex situ survey, and in much less elapsed time. This potentially enables better decisions to be made in less time. 

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