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Analytical description of concentration of radiation displacement defects in oxide crystals as function of electrons or neutrons energy

Potera Piotr

Advances in Materials Science

2022

Vol. 22, nr 3(73)

41--52

The main purpose of this work is the description of dependence of the concentration of radiation displacements defects (RDD) induced by electrons and neutrons in garnets, perovskites, silicates, germanates, and tungsted bronzes type crystals (Y3Al5O12, Gd3Ga5O12, YAlO3, LiNbO3, Bi4Si3O12, Bi4Ge3O12, Ca0.28Ba0.72Nb2O6) on the energy of particles by analytical function. The dependences were determined on the basis of calculations made using the Monte-Carlo method realized in the Atom Collision Cascade Simulation program. The results of calculations show that the concentrations of RDD reduced to one impinging particle increased initially with the particles energy and they saturates for the electron and neutron energy above 3-36 MeV, depending on crystal, sublattice and kind of irradiation particle. A wide range of energies for which the concentration of RDD is independent of the energy of particles (neutrons, electrons) makes them potential materials for the dosimetry of high-energy particles. The comparison of the concentrations of RDD calculated for different sublattices as well as for the cases of electrons and neutrons is made. In the case of irradiation with electrons, the relative concentration of RDD of the oxygen sublattice strongly depends on the energy of electrons and the crystal and varies in the range of 10-90%. In the case of neutrons, the relative concentration of RDD of the oxygen sublattice does not depend on the neutron energy and is in the range of 66-84% depending on the crystal.

Microhardness analysis of halite from different salt-bearing formations

Toboła Tomasz Tadeusz, Cyran Katarzyna, Rembiś Marek

Geological Quarterly

2019

Vol. 63, No. 4

771--785

Microhardness tests were carried out on single halite crystals. They were conducted on the (001) surface, with the indenter set in two directions: parallel to the halite face (010); and parallel to the (110) face. The halite crystals represent salt formations of different ages (Devonian, Zechstein, Badenian), depths (from 1835.5 to 195 m) and intensities of tectonic disturbance (horizontally stratified, salt dome, strongly folded). The measurement results revealed specific features of the halite crystals analysed. Firstly, the data obtained show microhardness anisotropy in halite crystals. Moreover, microhardness correlates with the depth of the salt-bearing formations. Halite crystals from deeper levels showed higher microhardness, though there was no correlation between the intensity of tectonic deformation and the average Vickers hardness (HV). The samples analysed show a variability of HV values and and of the shapes of imprints. These indicate zones where halite crystals are deformed at the atomic level and reflects the presence of defects in the crystal lattice. Such deformation is reflected in an irregularity of the strike of cleavage planes. Consequently, the analysis of imprint shapes is a useful method for the examination of ductile minerals and materials.