Measurement and folding-potential analysis of the elastic ?-scattering on light nuclei

Abstract

Dedicated to Professor Theo Mayer-Kuckuk on the occasion of his 60th birthday Differential cross sections of e-elastic scattering have been measured for the target nuclei XlB, 12C, 13C, 14N, lSN, and 160 at E=48.7 and 54.1 MeV and for the nuclei 170, 180, and 2~ at E=54.1 MeV. The experimental results were analysed in terms of the optical model using different complex potentials. Special emphasis is given to the application of the double-folding approach for the real part of the potential. The imaginary part is expressed in terms of Fourier-Bessel functions. Differential cross sections for the e-160 scattering over a wide energy range and for the elastic e-scattering for nuclei in the mass range A=ll up to A=24 at E=54.1MeV are analysed by this method. A close correlation between the absorptive part of the potential and nuclear deformation is observed.

Evidence for a parity dependence of the ?+20Ne interaction

“…A potential in line with those obtained for the A= 13-18 targets turns out to be completely unable to describe the backward rise seen in the Z~ ao) data: while the FM potential of Abele et al [14] nicely reproduces the A= 13-18 data, it completely fails to describe the Z~ angular distribution beyond 0em~--40 ~ This could have been expected from the absence of a pocket in the effective potential at the grazing angular momentum for potentials in line with the A= 13-18 potentials, if a mechanism similar to that found to be operative in 16 0 (a, ao) is sought to describe the Z~ anomaly. Indeed at lower energy (E, < 40 MeV) it has been shown [3] that the enhancement seen in 160(~, ao) at large angles is dominated by the internal wave contribution to the scattering amplitude, i.e.…”

“…This appears to be unattractive from a physical point of view, since potentials in line with those extracted at 54.1 MeV [14] are known, in the case of 160, to be smoothly connected with the unique potential fitting the higher energy data, and since on the other hand the few microscopic calculations devoted so far to the study of the isotope effect around target shell closure point to a slow and regular evolution with mass of the scattering properties of the sys- tem [16]. Despite these unsatisfactory features we attempted to analyze the 54.1 MeV data using deeper real potentials which would hopefully generate a substantial internal wave contribution at the considered energy.…”

“…The scattering data for targets between a3C and 180 are quite satisfactorily described in an optical model calculation [14] where the interaction is either parametrized directly or calculated within a folding model approach using a density-dependent effective nucleon-nucleon interaction. The volume integrals per nucleon pair of the extracted real FM potentials assume values between 350 and 380 MeV.fm 3, while imaginary volume integrals per nucleon pair scatter between 76.6 MeV-fm 3 for 160 and 126 MeV.fm 3 for 180.…”

“…For investigating the problem further systematic measurements like those recently reported the Abele et al [14] are most desirable. In their paper a-particle elastic scattering measurements on the whole angular range are reported for 11B, 12'13C, 14'15N and 160 at 48.7 MeV incident energy, and for the same targets plus 17'180, ZONe and Z4Mg at 54.1 MeV.…”

The study of inelastic scattering of alpha particles on nuclei 20Ne, 24Mg by methods strongly-connected channels

“…In [8] it was an experimental study of the elastic -scattering on some light nuclei with A = 11-24 at energies  -particles E = 48.7 and 54.1 MeV. Data were analyzed by different types of optical potential and including Michel type.…”