Light charged particle and neutron production in proton- and alpha-particle-induced reactions on Si-nat at energies between 20 and 65 MeV

摘要

Inclusive cross sections (d(2)sigma/d Omega dE, d sigma/dE, d sigma/d Omega and sigma(T)) for the production of neutron and light charged particles induced by protons of 26.5, 48.5 and 62.9 MeV and alpha-particles of 25.4, 45.5 and 57.8 MeV on Si-nat targets have been measured. The secondary particles (p, d, t, He-3, alpha, Li-6, Li-7 and Be-7) were detected at angles from 10 degrees to 165 degrees in steps of +/- 10 degrees with respect to the beam axis. Neutrons emitted in these reactions were only recorded in coincidence with, at least, one detected light charged particle. A comparison of the proton- and neutron-induced reactions on Si at E = 62 MeV shows evidence of charge independence of the nuclear force. The proton spectra from the two reactions scale as expected from the difference in proton-neutron and proton-proton quasi-free scattering cross sections. The new data are reproduced with moving source fits and are also compared with state-of-the-art nuclear reaction models. The codes used for this purpose, GNASH and TALYS, consider direct nuclear reactions as well as pre-equilibrium and compound nucleus emission, and were found to reproduce the general features of the experimental data, especially for the (p, p x) channel. More detailed comparisons with the data indicate that there is still room for improvement in these codes. (c) 2006 Elsevier B.V. All rights reserved.