Discharge patterns near surfaces of synthetic quartz caused by 200-keV electron irradiation

Discharge patterns near surfaces of synthetic quartz caused by irradiation with 200-keV electrons in a vacuum have been studied. As-grown +X and -X faces and as-grown Z faces cut from Y-bar crystals were examined. Three kinds of linear discharge channels parallel to the surface appear on the -X face; one is parallel to the Y axis and the others incline at angles of about 240 and 640 with respect to the Y axis, respectively. Such discharge channels do not appear on the +X face. The discharge channels appear along grooves of growth hillocks on the Z face. The formation of the discharge patterns is interpreted in terms of localized distribution of impurities and lattice defects. (auth.)