Elemental mapping with the ANSTO high energy heavy ion microprobe

ANSTO was among the first laboratories to use microscopic beams in Ion Beam Analysis. In these early experiments apertures were used to minimise the beam spot size rather than active focusing elements, such as quadrupoles. This tradition was continued with the ANSTO Milliprobe, which also uses apertures and has produced many interesting results for beam spot sizes down to 50μm. However, in order to be able to achieve the smallest spot sizes and use a wide range of IBA techniques on a microprobe, focussing of the ion beam with either electrostatic or magnetic quadrupoles is required. The high energy, heavy ion microprobe is intended to fill this gap in ANSTO's IBA facilities. The aim was not to duplicate existing proton microprobe facilities in Australia or internationally, but to design a microprobe that would utilise IBA techniques at high energies using heavy ions, which have become more common in the IBA community in recent years. These methods include high energy nuclear reactions and resonances as well as heavy ion elastic recoil detection analysis (ERDA). They are particularly useful to analyse the lighter element s such as, H, C, N and O. The primary aim was to establish the use of heavy ion techniques on an ion microprobe using spot sizes between 5-20μm, with sufficient beam current to perform an IBA measurement in a reasonable time. The results show that both X-Ray fluorescence and high energy resonance can be used simultaneous to map both light and heavy elements. Spot measurements of selected regions were also performed, which can lead to quantitative results. Furthermore, oxygen depth profiles can be extracted from such measurements