More accurate parameterization of positron implantation depth profiles for the sensitivity range of positron-based characterization techniques

Abstract

Techniques that employ positron annihilation spectroscopy are powerful tools to investigate defect structures and concentrations in materials. A hindrance to experimental design and the interpretation of results lies in the lack of agreement in the literature concerning the proper form of the positron implantation profile, a function that determines the sensitivity range for all non-slow positron annihilation spectroscopy techniques. Employing the dominant 22Na isotopic source, a positron implantation profile database of 270 common materials is published. The parameters for a novel implantation profile functional form providing superior agreement with simulation are derived. Finally, and most critically, an algorithm is presented and validated, which permits utilization of the published elemental implantation profile parameters to produce the positron implantation profile for any material of interest. This tool provides rapid calculation of the sensitivity range for all positron annihilation techniques, enabling more informed experimental design and more accurate knowledge of the spatial distribution of defects in materials.