Sputter ion source cathode pit reconstruction by stylus profilometer, optical techniques and X-ray micro computed tomography

Abstract

In Caesium sputter ion sources of negative ions, SNICS, an accurate reconstruction of pit profiles is important to assess the efficiency of cathode material utilization to increase the output of negative ions. Highly accurate pit profile measurements in sputter cathodes are difficult to perform for geometries where the depth is large compared to the diameter. In this paper, optical confocal microscopy, stylus profilometry and X-ray micro-computer tomography are used successfully to reliably reconstruct such high aspect ratio cathode pit geometries. Simulations of Cs+ beam trajectories and calculated cross-sectional current density distributions are consistent with the observed pit profiles. Experimental results demonstrate the practicability of the proposed measurement techniques for SNICS cathodes and other structures with complex surface topographies.