The 40K nuclide emits a single gamma ray with an energy of 1460.8 keV and solely this decay is utilized to obtain the relative concentrations of natural potassium in an area. The nuclide 40K has an abundance of 0.0117% of naturally occurring potassium (http://www.ciaaw.org/isotopic-abundances.htm) but the 40K emission is commonly very strong in natural spectra, due to the abundance of naturally occurring potassium in nature. An active stabilisation function in the winTMCA32 softwarewas used to correct for energy drift, which results from temperature changes while surveys were conducted on the site. The 1460.8 keV emission of 40K was chosen as centroid for stabilisation and the fine gain were automatically adjusted by the winTMCA32 software to correct for any drift from the centroid.