A comparison of three X-ray emission techniques with applications to thin film and bulk samples including low energy heavy-ion particle-induced X-ray emission spectroscopy.

摘要

The three techniques of Particle Induced X-ray Emission (PIXE), X-ray Fluorescence (XRF) and Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS) are described. The equipment used for each is described in some detail, and some of the advantages and disadvantages of each technique are discussed. Vacancy lifetimes and fluorescence yield are discussed. A system to perform PIXE analyses in a Nanofab focused ion beam is discussed. Calculations are then described which compare the three techniques for depth of analysis. Calculations are shown which give an idea of the ionization and x-ray production cross-sections of these three techniques. Two methods of calculating the energy for maximum K-shell ionization cross-section for incident electrons and protons result in two charts of such values. The cross-sections of the three techniques are compared. The change in peak height with change in Z of the sample material is explored for X-ray fluorescence in thin films.; In part 2, a computer program known as Inner Shell Ionization Cross Sections (ISICS) which uses the Energy loss Coulomb Perturbed Stationary State Relativistic theory with United Atom correction (ECPSSR-UA) model is used to generate theoretical data on cross sections. The cross section data from this program is then verified by checking against experimental data to ascertain whether ISICS is an accurate or conservative program for predicting x-ray production cross sections. This program is then used to generate predictions for PIXE in the Focused Ion Beam (FIB-PIXE) for three incident ions at 280 keV for selected x-ray lines. It is concluded that a lithium ion source is by far the best way to attempt FIB-PIXE.