Excitation functions of proton-induced reactions in 16O at medium energies

Abstract

Protons elastically and inelastically scattered from 16O were observed at lab angles between 60° and 160° using NaI(Tl) detectors. The incident beam energy was varied in approximately 200 keV steps from 21.25 to 33.12 MeV and in 500 keV steps at higher energies up to 38.5 MeV. Angular distributions at the same energies were also measured for inelastic proton scattering leaving the 16O nucleus with excitation energies of Q = 6.05, 6.13 MeV and Q = −8;.88 MeV. The excitation functions for the (p, d) and (p, α) reactions were measured at 70° for the same energy range, and the (p, t) reaction was observed above 31 MeV. The elastic scattering angular distributions have been integrated over the angular range 100°–160° and anomalies are observed. An optical-model-with-resonance analysis of the data is presented which indicates states at E p = 21.6, 22.6, 23.5, 24.7, 26.4, 28.3 and 30.1 MeV with Jπ assignments 9 2 + , 9 2 + , 7 2 + , 7 2 + , 7 2 − , 5 2 − and 5 2 + , respectively. A coupled-channels calculation has also been compared with the elastic and inelastic scattering ( Q = −6.05, −6.13 MeV) angular distributions.