Visual ion-beam images produced by electron and ion-beam interaction on surfaces

Abstract

Two-dimensional images of 1–5-keV ion beams incident on solid surfaces have been obtained by a method similar to that used in a scanning electron microscope. This easily applied technique produces visual real-time images, whose size correlates well with beam-current profile measurements; actual photographs of two such images obtained for different width ion beams are presented. Various target materials have been examined, but only insulators were found effective in producing ion-beam images by this method. Some mechanisms that may relate to the interaction of ion and electron beams on surfaces are discussed. Those processes that seem to be basic to understanding the surface interactions responsible for this imaging effect are enhanced surface conductivity and charge neutralization. The technique itself has direct application to ion-beam alignment and diagnostics. The use of coincident ion and electron beams presents a new technique that is potentially useful for the investigation of surface interactions.