The problem of diffusion during charged particle activation analysis; the case of¹⁸F in pure germanium single crystals

Abstract

During ion bombardment, thermal diffusion and radiation enhanced diffusion of atoms occur. These phenomena may be a source of error in ion beam analysis, particularly in radioactivation analysis if contaminant surface atoms are present. It is shown here that penetration of¹⁸F (derived from surface oxygen by nuclear reaction) in germanium single crystals, does not extend appreciably farther than the maximum range of the recoiling¹⁸F nuclei. Since the analyzed depth is over an order of magnitude larger than the recoil, the validity of charged particle activation analysis at the ppb level in the present case (oxygen→¹⁸F in germanium), is clearly demonstrated.