Description of ANSTO’s confocal microprobe simulation program

Abstract

The elemental composition of a sample can be determined by the analysis of its characteristic X-ray spectrum. Proton induced X-ray emission (PIXE) has been used for a number of decades for this purpose (e.g. Clayton et al. 1981). More recently techniques aimed at enhancing the spatial resolution in the samples have been investigated. One of these techniques is to restrict the field of view of the X-ray detector by the use of a polycapillary lens. In such a confocal set-up the sample is driven across the sensitive volume formed at the intersection of the proton beam and the area from which the lens collects radiation (Zitnik at al. 2009, Wolff et al. 2009). Here we detail early investigations of a set-up with a polycapilary lens attached to the detector and a FORTRAN program which calculates the yield from a homogeneous material. Once the working of the set-up and program have been investigated and validated for homogeneous sample, heterogeneous samples can be considered.