In situ gamma-ray spectrometry for the measurement of uranium in surface soils

The application of the technique of in situ gamma-ray spectrometry to the measurement of uranium isotopes in surface soils is described. A basic review of the in situ methodology using high resolution germanium gamma-ray spectrometers is given and specifics on calculated fluences, dose rates in air, and calibration factors are provided for relevant uranium isotopes and their progeny. The influence of the uranium depth distribution on measured concentrations is examined as it pertains to the comparison of in situ results with those obtained with soil sampling. Results from the analysis of spectra collected in the vicinity of the Fernald Environmental Management Project are presented as an example of the application of the technique.