Application of an iterative maximum-likelihood algorithm in PIXE depth profiling of trace elements

Abstract

We have applied an iterative maximum-likelihood algorithm to extact trace element depth profiles from PIXE yields data for various incident proton energies. This algorithm is based on the exact stochastic model of X-ray yield measurements. We have tested the algorithm using calculated X-ray yields generated from a PIXE simulation program. Several profiles of phosphorus with depth extensions of a few micrometers in a silicon matrix are used to generate the X-ray yields. The maximum-likelihood algorithm is able to reconstruct the depth profiles from these yields successfully even when Poisson noise is added to the yield data. The reconstructed profiles are smooth and do not suffer from erratic fluctuations normally encountered in other conventional deconvolution methods. © 1994.