Monte Carlo simulation of characteristic secondary fluorescence in electron probe microanalysis of homogeneous samples using the splitting technique

Electron probe microanalysis (EPMA) is based on the comparison of characteristic intensities induced by monoenergetic electrons. When the electron beam ionizes inner atomic shells and these ionizations cause the emission of characteristic X-rays, secondary fluorescence can occur, originating from ionizations induced by X-ray photons produced by the primary electron interactions. As detectors are unable to distinguish the origin of these characteristic X-rays, Monte Carlo simulation of radiation transport becomes a determinant tool in the study of this fluorescence enhancement. In this work, characteristic secondary fluorescence enhancement in EPMA has been studied by using the splitting routines offered by PENELOPE 2008 as a variance reduction alternative. This approach is controlled by a single parameter NSPLIT, which represents the desired number of X-ray photon replicas. The dependence of the uncertainties associated with secondary intensities on NSPLIT was studied as a function of the accelerating voltage and the sample composition in a simple binary alloy in which this effect becomes relevant. The achieved efficiencies for the simulated secondary intensities bear a remarkable improvement when increasing the NSPLIT parameter; although in most cases an NSPLIT value of 100 is sufficient, some less likely enhancements may require stronger splitting in order to increase the efficiency associated with the simulation of secondary intensities.publishedVersionFil: Petaccia Trobatto, Mauricio Germán. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Petaccia Trobatto, Mauricio Germán. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Petaccia Trobatto, Mauricio Germán. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina.Fil: Seguí Osorio, Silvina Inda María. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina.Fil: Seguí Osorio, Silvina Inda María. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Castellano, Gustavo Eugenio. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Castellano, Gustavo Eugenio. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Castellano, Gustavo Eugenio. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina.Física Atómica, Molecular y Química (física de átomos y moléculas incluyendo colisión, interacción con radiación, resonancia magnética, Moessbauer Efecto.