Ultraclean radioisotope marking by nuclear stimulated desorption

Abstract

A method for ultraclean radioactive marking is presented, utilizing the process of nuclear stimulated desorption. It employs a sequence of two slow radioactive decays. The primary decay causes a nucleus to desorb from a substrate onto which it had been placed. The desorbing daughter nuclei, being themselves radioactive, then constitute an ultraclean marking flux. A manifestation of this mechanism for the special case of the 47Ca -47Sc + 47Ti decay is described. An application to end-point detection in wet etching is presented and quantitatively simulated.