The Computer Code for Calculations of the Positron Distribution in a Layered Stack Systems

Abstract

In this paper we present experimental and theoretical studies of the implantation pro le of positrons emitted fromNa radionuclide into layered sample. The measured pro le for the nonsymmetrical, around the positron emitter, stack of aluminium and silver foils was measured using the depth scanning of implantation pro le technique. For the description of the obtained results two theoretical approaches were applied. The rst one was the Monte Carlo simulation using the GEANT4 tool kit. The generated pro le does not reproduce accurately the experimental pro le. We proposed the multiple scattering model based on the fact that a positron due to backscattering can travel as an energetic particle several times through the whole sample before it annihilates. In this model absorption is also taken into account. The multiple scattering model algorithm was implemented in the LYS-1 program. The calculated pro le using the LYS-1 program reproduces the experimental pro le with much better accuracy.