Gamma spectrometry analyses of georadiometrical rock samples

The gamma-spectrometric method realizes the separate determination of U(Ra), Th and K. In Laboratory conditions has been reached the determination of U(Ra). The beginning from the content 2 ppm and rfom 1% for K. For this purpose it has been used the 1 and 4 channel gamma-spectrometric analyzer with Nal(Tl) scintillation counter crystal. Detector of a 103 cm (Ø = 50 x 50 mm). The arrangament for laboratory conditions has for a measurement geometry with a vessel of "marinali" type 200 cmm volume. The study of main factors which influence in the gamma spectrometric measurements, name the technical, physical, geometrical and time parameters has been carried out. Calibration has been made with radioactive pattern speared from natural samples which have been chemically analysed before. In the table are displayed Calibration Data significative for laboratory conditions. Geometry measurements detector sample ? 4 ?, in regime: spectrum stabilization. Gamma spectrometics determination of uranium, thorium and potassium in rock samples are presented on table and figure.