Analytical continuous slowing down model for nuclear reaction cross- section measurements by exploitation of stopping for projectile energy scanning and results for ~(13)C(~3He,α)~(12)C and ~(13)C(~3He,p)~(15)N

摘要

Ion beam analysis is a set of precise, calibration free and non-destructive methods for determining surface-near concentrations of potentially all elements and isotopes in a single measurement. For determination of concentrations the reaction cross-section of the projectile with the targets has to be known, in general at the primary beam energy and all energies below. To reduce the experimental effort of cross-section measurements a new method is presented here. The method is based on the projectile energy reduction when passing matter of thick targets. The continuous slowing down approximation is used to determine cross-sections from a thick target at projectile energies below the primary energy by backward calculation of the measured product spectra. Results for ~(12)C(~3He,p)~(14)N below 4.5 MeV are in rough agreement with literature data and reproduce the measured spectra. New data for reactions of ~3He with ~(13)C are acquired using the new technique. The applied approximations and further applications are discussed.