Imaging gas concentration in the field ion microscope: a theoretical analysis

Abstract

A Boltzmann equation method for calculating the gas concentration in the field ion microscope is proposed. A simple model for the molecule’s bouncing movement is presented. Numerical results are given and the formation of an imaging gas adsorbed layer is discussed. Within this model, no evidence is found which suggests that local variation in imaging gas concentration is the basic mechanism of image formation in the FIM. The results show limits on the values of tip field and or tip temperature, for which an adsorbed layer can be formed.