FIELD: determining concentration of natural and man-made radioactive isotopes during hole logging. SUBSTANCE: standard spectral of gamma-rays in base models and gamma-spectral in analyzed samples are measured; in addition, tuning spectrum in mixture sample containing all required isotopes is measured, and it is used to pre-match energy scales of standard spectra in calculating fractions of standard spectra in gamma-spectrum of analyzed sample; its energy scale is brought to agreement with energy scale of pre-matched standard spectra; then concentration of isotopes in analyzed sampled is calculated using data on concentration of these isotopes in base models including difference in absorbing, dissipating, and radiating characteristics of analyzed sample and base models. Device implementing this process has unit transmitting data to surface incorporating master oscillator, storage cell counter, control device generating read commands, and storage flip-flop one of whose inputs receives information from storage integrated circuit output and other input accepts read-out command read-out command. EFFECT: facilitated procedure. 22 cl, 2 dwg
