A Portable Ge(Li) Detector for Field Measurement of Radionuclides in the Environment

A description of a portable Ge(Li) field spectrometer and its application to in situ measurements is given. The mathematical techniques of calibrating the spectrometer so that field spectrometer counting rates may be converted into units of soil activity are developed. The quantification of gamma-ray emitting radionuclides in the field has proven to be more sensitive than laboratory analysis using Ge(Li) anticoincidence shielded spectrometers. This was demonstrated by obtaining approximately the equivalent statistical accuracies for quantifying several radionuclides from a 30 min field count as compared to a 1437 min laboratory analysis. A comparison between the results obtained from field analysis with those obtained by returning the samples to the laboratory are given for natural radionuclides and 137Cs. An example of qualitative spectral data obtained from field measurements of gaseous emissions from a BWR reactor is also given.