EXPERIMENTAL-DETERMINATION OF THE INELASTIC MEAN FREE-PATH FOR CU, AG, W, AU AND TA, IN THE ENERGY-RANGE 500-3000 EV BY ELASTIC PEAK ELECTRON-SPECTROSCOPY AND USING NI REFERENCE SAMPLE

The inelastic mean free path (IMFP) is the most important electron transport parameter. The value of IMFP can be determined by electron reflection experiments (EPES) supported by the Monte Carlo theory with the multiple elastic scattering events considered. The values of IMFP for the high atomic number elements obtained from such a model and applying Al standard were found to be in reasonable agreement with the theoretical values. Recently Ni has been proved to be a more adequate reference sample due to the lack of inelastic losses appearing in the vicinity of the elastic peak. In the present work the energy dependence of the IMFP for Cu, Ag, W, Ta and Au using Ni standard was evaluated by EPES in the energy range 500-3000 eV. The Ni standard of high qualify was used, where its surface roughness was verified by scanning tunnelling microscopy. Reasonable agreement with Tanuma at al. results was obtained in the energy range 500-2000 eV. Above 2000 eV the obtained results were in agreement with the values by Ashley and Tung.