Ultra thin layer activation by implantation of recoil radioactive nuclei: Experiments and simulations

The ultra thin layer activation (UTLA) by recoil implantation of heavy radi oactive nuclei has a great potential in wear or corrosion rate measurements , because of its nanometric sensibility. In regard of the complexity of its calibration, a Monte Carlo simulation program (Implantation of Recoil Ions Simulation) was developed to calculate the depth profile of implanted nucl ei. It is associated to SRIM software for the transport of particles in mat ter. In this paper, the different simulation parameters and the potentialit y of IRIS program are described. Implantation experiments with the Fe-56(p, n)Co-56 nuclear reaction have been performed at 22.8 MeV protons to measure the angular and depth distributions of Co-56 nuclei emerging from the iron target. In comparison with experiments, the simulated angular distribution has a good magnitude of implanted activity, but presents an excess of nucl ei in high angles of implantation. This excess comes from too great emissio n probability around the critical angle. For depth profile, the simulated s pectrum of transmitted particles is too energetic. (C) 2000 Elsevier Scienc e B.V. All rights reserved.