Monte Carlo Simulation of Secondary Fluorescence in Electron Probe Microanalysis using the Splitting Technique

M. PETACCIA; G. CASTELLANO; S. SEGUI

MICROSCOPY & MICROANALYSIS

CAMBRIDGE UNIV PRESS

Lugar: Cambridge; Año: 2015 vol. 21 p. 753 - 758

1431-9276

Electron Probe Microanalysis is based on the comparison of characteris-tic intensities induced by primary 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. Since 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. The routine package PENELOPE allows to use different alternatives for variance reduction; one of these techniques is called splitting and consists in replacing a particle of interest by NSPLIT replicas in exactly the same conditions, raising in this way the statistics associated with a particular event. NSPLIT must be high enough to reduce the variance but not so big to distort the results. In order to study the characteristic fluorescence enhancement in EPMA, the influence of the choice of the splitting factor NSPLIT in the uncertainties associated with secondary intensities was studied as a function of the accelerating voltage and the sample composition in a simple binary alloy in which this effect becomes relevant.