Radiation Blistering: Interferometric and Microscopic Observations of Oxides, Silicon, and Metals

Abstract

Photographs and descriptions of the phenomena are given. Most of the observations were of magnesium oxide, a few were of spinel and corundum. The fringe systems arising from a blister (two films on a substrate) are described. Results are given for miscellaneous H⁺, D⁺, He⁺, and He⁺⁺ bombardments, 0.025–4 MeV. Measurements are given of blister heights, diameters, shell thicknesses, and depths of cavities left after blister shells break away (exfoliate). Effects arising from superficial deposited films are described. Blistering was found on polycrystalline copper bombarded with H⁺ or He⁺ and on polycrystalline nickel with He⁺ only. Blistering was not found on several other metals bombarded similarly. For the oxides, blistering was first noted at ∼3×10¹⁷, while for the metals at ∼8×10¹⁷. The effects of gas permeability, radiation expansion, and elastic moduli on blister growth are discussed. The dispersion of refractive index of magnesium oxide is given.