Accumulation of radiation defects and modification of micromechanical properties under MgO crystal irradiation with swift 132Xe ions

Accumulation of F-type defects under irradiation of MgO crystals by 0.23-GeV Xe-132 ions with fluence varying by three orders of magnitude has been investigated via the spectra of optical absorption and low-temperature cathodoluminescence. The number of single centers continuously increases with fluence without any marks of saturation. At the highest fluence, a mean volume concentration of 3.1 x 10(19) and 3.35 x 10(19) cm(-3) is reached for F and F+ centers, respectively. The F+ emission strongly dominates in the cathodoluminescence of irradiated MgO and its enhancement with fluence is detected. However, the creation efficiency of the F-2 aggregate centers is very low and fluence dependence has a complicated shape. Radiation-induced changes of micro-mechanical properties of the same samples have been analysed; the depth profiles of hardening correlate with the ion energy loss. A joint contribution of ionization and impact mechanisms in the formation of structural defects under MgO irradiation with Xe ions is considered.