Channeling studies through characteristic radiations

Abstract

The yield of K-shell fluorescence radiation emitted from aluminium crystals is measured during bombardment with 1H+, 3He+, 4He+, and 20Ne+ ions in the energy range 100–200 keV under channeling conditions. The yield as a function of the angle between the beam and a crystallographic direction shows a minimum; the half-width is independent of the ion mass and varies as the square root of the incident charge. Under proton bombardment the yield curve for copper K-shell excitation is somewhat wider than for L-shell excitation. The difference diminishes with increasing energy and vanishes near the upper end of our energy range. Channeling in organic crystals is demonstrated along the c direction of thin anthracene crystals in penetration experiments with 5.48-MeV alphas. The yield of optical fluorescence radiation emitted from the anthracene target during alpha bombardment shows a minimum when particles are incident along this channeling direction.