A semi-empirical method for the determination of the spatial distribution of channeled ions

Abstract

A method is presented for the determination of the flux profile of ions channeled in the main directions of a crystal lattice. The Lindhard continuum model is used, but in the analytical calculations a parameter is introduced which encompasses the influence of the energy loss of the channeled ions in the crystal as well as the influence of lattice defects and surface layers. This parameter may be interpreted as the root-mean-square angular spread of the ion beam. Its value is determined by fitting the calculated yield of a close encounter reaction with solute atoms at definite interstitial sites to the yield found experimentally. The method was tested on boron atoms implanted in tungsten single crystals.