Backscattering studies of 7Li, 12C and 16O ions at energies 3–15 MeV

Abstract

We report the experimental results on the backscattering analysis of 3.0–9.0 MeV 7Li, 12C ions and 3.0–15 MeV 16O ions. Energy resolution and mass resolution for these ions were measured on a double layered Au Cu thin film (50 Å thick) from backscattering spectra using a passivated implanted planar Si (PIPS) detector (Canberra PD 50-11-300). The backscattering data from top Au film (25 Å thick) and natural Cu layer were used to determine the detector energy resolution and mass resolution, respectively. Our measured spectra show the advantage of using PIPS detector for 7Li ion resulting to a good energy resolution. The measured value is 21 keV for 5 MeV 7Li ions as compared to 36 keV obtained previously using a partially depleted Si detector. As for mass resolution for 7Li, 12C and 16O ions our measured spectra show a clear separation of 63Cu and 65Cu peaks. To examine the accuracy of the stopping power for these heavier ions in different elements predicted by TRIM-95, we measured the backscattering spectra on thin films of Al, Cu and Ag, and determined the corresponding thickness from a RUMP analysis and compared the backscattering data for the 4He ions.