High spectral and angular resolution studies of sputtered zirconium atoms

We present the first results from a new apparatus for high spectral and angular resolution studies of sputtered neutral species. The sputtering experiments employ laser‐induced fluorescence and a compact fiber‐optic‐based detection system to yield state‐specific angular distributions for the sputtered atom flux. The angular resolution is of the order of 3° and a 260 MHz residual Doppler shift is estimated for the observed atomic transitions. The angular distribution for ground‐state zirconium atoms shows clear deviations from the cosine dependence expected from linear cascade theory when sputtered by 1.5 keV Ar+ ions incident at 60° from the surface normal. The peaking of the distribution in the forward direction suggests that a significant fraction of the atoms is ejected by a direct mechanism.