Calibration of a portable intrinsic Ge gamma-ray detector using point sources and testing for field applications

A simple procedure using point sources is described for the calibration of portable high-resolution gamma-ray detectors used in field surveys. The point source data are fitted by empirical equations that are used to calculate efficiency for field applications. Two models for the distribution of radionuclides are treated: a thin surface-film model and a vertically homogeneous model. The success of the procedure has been demonstrated by field applications in plots where the levels of contamination are known.