Multiple secondary ion emission from keV massive gold projectile impacts

We present the first experimental data on secondary ion emission characteristics from the impact of 26 keV Au3+ and 74.6-114.6 keV Au4004+. In particular we show secondary ion yield distributions and secondary ion and coincidental ion yields of molecular cluster ions from single impact events. The target consisted of an amorphous (HfO2)0.6(SiO2)0.4 layer deposited on a Si wafer. Large increases in higher order emission events and both secondary ion and coincidental ion yields within these events were observed for bombardment with Au4004+ even though the energy per atom of this projectile is more than an order of magnitude less than Au3+.