Holistic Mapping in an Electron Microprobe

Abstract

When an electron beam interacts with a solid target a number of interactions occur which produce electrons, x-rays and light. Typically in an electron microprobe analyser (EPMA) both the electron and x-ray signals are collected for analysis and imaging. However, if the EPMA is equipped with an optical spectrometer then all three signals can be collected. Commonly, the optical or CathodoLuminescence (CL) spectrometer is a monochromator type and can only collect a single frequency or small range of frequencies at a time. Simultaneous collection of the complete visible spectrum is not possible. The collection optics associated with the spectrometer often must be moved into place to start collection, this then obscures the other detectors and prevents simultaneous collection. At CSIRO Minerals an optical spectrometer has been integrated into a JEOL 8900R EPMA and allows simultaneous collect of all light, x-rays and electron signals. This form of mapping, termed Holistic Mapping, has significant advantages over traditional mapping in that it removes the need to have a priori knowledge about what the important frequencies are that will provide the solution to the problem at hand.