Analysis of the Dynamic and Structural Characteristics’ Behavior in NaCl Single Crystals Pre-deformed and Х-ray Irradiated

Pulse-echo method in the frequency range 37.5-232.5 MHz has been used to study the behavior of dislocation decrement d(f) on X-ray irradiated to doses 0-600 R NaCl single crystals with the residual strain value of 0.5 % at room temperature. It has been found out that with the increasing doses of radiation, the effect of amplitude damping of the dislocation resonance can be observed, which leads to a marked restoration of initial acoustic characteristics of the crystals. It also noted that high-frequency asymptote for these theoretical profiles are identical which is characteristic only for acoustic testing of irradiated crystals. From the frequency curves, taken from crystals with different doses of radiation, the dependencies of the viscosity coefficient B and the average effective length of the dislocation segment L on the dose of irradiation  have been determined in the framework of Granato-Lucke's string dislocation theory. In the framework of the Stern and Granato model, the behavior of m(), fm() and L() curves has been studied. The validity of the theoretical prognostications concerning increasing or decreasing with the exposure time according to the law (1 + t)2 parameters m, fm, and L have been proved. A good match of the calculations’ results with the theoretical curve L() by Stern-Granato and Granato-Lucke theories has been noted. Obtained results show, that the parameter B does not depend on the irradiation dose in the range 0-600 R. It confirms the validity of the views that the coefficient of dynamic damping of dislocations B is a fundamental characteristic of the crystal depending only on the interaction of dislocations with the phonon subsystem of the crystal and not depending on the parameters of its dislocation structure.