Investigation of partial sputtering of lithium from a binary Al/Li alloy with laser induced fluorescence

Sputtering investigations of an Al/Li alloy containing 9.1 at-% of lithium have been performed for 6 keV helium ion bombardment. Absolute particle densities and velocity distributions of the sputtered neutral lithium atoms were measured with laserinduced fluorescence. The amount of sputtered lithium was found to be constant for target temperatures ranging from room temperature up to 500° C. The mean transport velocity and the sputtering yield of the Li component have been calculated from the measurements. Thermal evaporation of neutral Li atoms could be measured independently of the presence of the helium beam for target temperatures above 300° C. The experimental results indicate that the surface is covered by lithium with at least several atomic layers even under highcurrent ion irradiation.