Accounting for spatial variability and fields of view in environmental gamma ray spectrometry

Spatial variability is an important feature in many environmental studies, which influences comparison estimates of environmental radioactivity from soil samples and in-situ or airborne γ-ray spectrometry. Comparisons between ground based and airborne gamma ray spectrometry are needed both for interpretation and for calibration purposes. However, under normal environmental conditions such comparisons may be affected by the considerable differences in the spatial response of these measurement techniques. A sampling methodology is presented which enables soil sample derived estimates of environmental radioactivity to be effectively compared with in-situ and aerial survey results. Examples of calibration sites and derived sensitivity estimates for 137Cs are presented for a range of environmental contexts.