Charge state of alkali atoms scattered by Mo and W surfaces

Abstract

From an experimental study it has been established that the charge states of particles scattered by the surface of refractory metals (W, Ta, Mo) during bombardment by neutral atom and ion beams of alkali metals (Li, Na, K), do not depend on charge states of the primary particles. It has been shown that angular and energy distributions of atoms and ions scattered from the bombarded surface of both ion and atom beams are similar to each other. A method for the direct detection of the neutral fraction yield of particles scattered from metal surface has been developed. In this method a second (auxiliary) target surface was used which had a higher work function than the target surface under investigation. In the yield of scattered particles, the ratio of the ionized component to the neutral component is the same for both target surfaces. This fact has made it possible to measure the yields of neutral particles. Thus, the scattering coefficients for ion and neutral fractions of scattered alkali atoms were determined. The measured and calculated dependencies of the ionization degree of η + for alkali particles are compared.