Cesium Ion Sputtering of Aluminum

Abstract

A neutron activation technique has been developed to investigate cesium-aluminum sputtering in measured, rarefied atmospheres of oxygen. The sputtering yield was measured as a function of cesium ion energy and as a function of the ratio of oxygen molecular flux arriving at the target surface to sputtered aluminum flux leaving the surface. In all measurements the ion beam was normal to the monocrystalline aluminum target surface and to the (110) crystallographic plane. The yield increased monotonically from 0.74 (atoms/ion) at 1 keV to 2.4 at 10 keV and was unaffected by flux ratios less than 0.2. The yield decreased for higher values of the flux ratio and eventually reached a saturation value where it is conjectured that a surface film of Al2O3 is maintained.