eng Science and Education Publishing International Journal of Physics 2333-4576 2016-03-16 4 2 37 42 10.12691/ijp-4-2-3 IJP2016423 article Pop O.M. 1 Simulik V.M. vsimulik@gmail.com 1 Stets M.V. 1 Institute of Electron Physics of the National Academy of Sciences of Ukraine, Uzhgorod, Ukraine The radioactive nuclei decay of the nuclides in the 232Th, 235U and 238U series is under consideration. The Bateman-Rubinson system of differential equations is applied. The activity of any n-th nuclide of the series has been calculated. The standard nuclide spectra are found and are compared with experimental nuclide spectra of activities. The results of the measurements are the time parameters, which determine the event date. The examples of the measurement of the experimental nuclide spectra in the nuclear gamma spectrometry of the point technogenic samples have been considered. http://pubs.sciepub.com/ijp/4/2/3/ijp-4-2-3.pdf ²³²Th ²³⁵U and ²³⁸U series standard sets of nuclides technogenic samples nuclear gamma spectrometry experimental nuclide spectra standard nuclide spectra of activities decomposition