Angular and energy distributions of secondary ions in the sputtering of gold by swift Au(n) clusters

摘要

Angular and energy distributions of negative secondary ions Au_n (n = 2-7) emitted from gold targets by gold cluster projectiles Au_4 and Au_9 at 200 keV per atom have been measured. A 256-anodes channel plate based detector for simultaneous detection in time of flight measurements was used. It is shown that angular distributions are rotationally symmetric with respect to the surface normal. They depend on the ejection energy. The energy spectra of the different emitted ions have similar shapes with almost the same mean energy. Energy spectra are satisfactorily reproduced by a spike-like model.