A Monte Carlo calculation of the x-ray production from multilayer samples

The X ray generation and absorption from a sample in an SEM or Electron Microprobe depends upon the geometry as well as the composition. Various schemes for calculating the X-ray signal from a homogeneous sample have been developed but few have addressed the problem associated with the presence of distinct microstructures. We have developed a Monte Carlo program to calculate the signal production from a multilayer sample as a first step to the incorporation of microstructural effects.The X-ray production from a layered structure is different from a homogeneous sample because the signal production and absorption are discontinuous. The differences can be calculated if the layer thicknesses and positions can be taken into account. The principle behind the calculation we have undertaken is the continuously monitor the energy and position of the electron in the specimen. Each trajectory is calculated in the usual stepwise manner except that the step size and scattering probability are continuously adjusted to accommodate the scale of the microstructure.