Features of Structural Changes in Travertine Like Barite Influenced by X-Ray Irradiation and Thermal Exposure

The results of our research on travertine-like barite by electron paramagnetic resonance (EPR) are presented. The growth of these crystals was held in continuous motion of gas-water solutions at a constant radiation exposure of the nuclei 226 Ra, 232 Th and 40 K. The objective of this work was to identify the crystal-structure features of travertine-like barite associated with growth conditions under the influence of radiation exposure. Radiographic studies of barite samples have shown that the aggregates are virtually mono-mineral formations. It has a compressed unit cell with lower volume and higher density compared to the parameters of sedimentary barites. Only weak lines of the EPR spectrum of the ion-radical SO 2 − were fixed in the natural sample of barite. Therefore, laboratory experiments were carried out with X-ray ionization of samples, not only of the original rock, but also of samples exposed to thermal annealing. The EPR spectra of the following ion radicals: О − (g xx =2.0186; g yy =2.0121; g zz =2.0093), SO 2 − (g xx =2.0033; g yy =2.0126; g zz =2.0105) and two type - SO 3 − (I) (g xx =2.0034; g yy =2.0024; g zz =1.9995), SO 3 - (II) (g xx =2.0076; g yy =2.0022; g zz =1.9979) were detected after X-ray irradiation. The intensities of the lines of the observed EPR spectra of ion radicals change with annealing temperature. Paramagnetic centres form an integrated system with the structure of the crystal. Within the system, the transfer of electrons and holes is observed.