Polygonization of NaCl single crystal surfaces by electron bombardment

Abstract
The bombardment with electrons of NaCl crystals reveals in time a surface polygonization. This polygonization has been observed on the irradiated zones, as well as outside them. Our experiments have indicated that the polygonization is revealed only if the crystal is illuminated during or after the bombardment. Under the action of the light the nature of defects (especially the F centres) is changed and consequently is affecting the mechanical relaxation.