Isobaric analogue resonances in 141Pr by elastic and inelastic proton scattering from 140Ce

Abstract Excitation functions and angular distributions for the elastic and inelastic proton scattering from 140 Ce have been measured. In the case of the elastic scattering, excitation functions have been taken in the energy range from 8.80 MeV to 12.00 MeV in steps of 5, 10 or 20 keV at the following scattering angles: 90.0°, 103.8°, 122.6°, 140.8°, 149.4° and twice at 170.0° whereas for the reaction 140 Ce(p, p 1 ), the energy range has been from 9.50 MeV to 11.70 MeV at the eight scattering angles: 50°, 60°, 70°, 130°, 140°, 150°, 160° and 170°. Sharp resonances in the compound nucleus 141 Pr corresponding to the isobaric analogue states of the low-lying levels in 141 Ce up to an excitation energy of 1.8 MeV have been observed in the elastic and inelastic channel. An analysis of the excitation functions of the (p, p 0 ) reaction and of the excitation functions and angular distributions of the (p, p 1 ) reaction for all measured scattering angles has been performed. The results of the analysis are a set of resonance parameters, such as resonance energy, total width, proton partial width, parity and angular momentum of the resolved resonances observed in the highly excited compound nucleus. Good agreement has been obtained between the (p, p 0 ) and (p, p 1 ) experiments and with the data of the (d, p) reaction on the same target nucleus. The inelastic scattering shows clear indications of a direct interaction amplitude coherently superimposed on the predominant Breit-Wigner resonance amplitude. Finally, Coulomb displacement energies were calculated and the resulting nuclear radii were compared with other independent measurements of the nuclear radius.