In-situ spectrometry of 137Cs in the soil by an unfolding method

The approach is based on in-situ measurements performed with a portable high-resolution germanium γ-spectrometer and on calculations of the depth distribution by an unfolding method. To unfold the depth distribution of 137Cs concentration in soil four detector responses and the iterative procedure SAND II were used. The detector responses consist of the responses to primary 662 keV photons and t photons scattered in soil with the rest energies of 620-655 keV. The detector is used with and without collimator. The method is sufficiently sensitive for measurements of 137Cs concentration in soil 10 years after the Chernobyl accident. The result are compared to laboratory analyses of collected soil samples and with a standard method of in-situ spectrometry. (author). 3 refs., 5 figs., 1 tab