Medium-Energy Ion Scattering Analysis with 50 keV He+ by the Time-of-Flight Technique

A newly developed time-of-flight spectrometer for medium-energy ion scattering is presented. The system mainly consists of a 60 kV duoplasmatron ion source, a beam chopper and an annular microchannel plate. Time and depth resolutions are found to be 7.8 ns and 2.9 nm, respectively. The probing depth is limited by the multiple scattering effect and is estimated experimentally to be up to ~20 nm for Au.