Elastische und inelastische Streuung von 104 MeV Alpha-Teilchen an58,60,62,64Ni

Abstract

Elastic and Inelastic Scattering of 104 MeV a-Particles from 5s, 60, 62, 64NiDifferential cross sections are measured for the elastic and inelastic scattering of 104 MeV ~-particles from 5s,60,62,64Ni" The experimental results are analyzed in terms of coupled channels on the basis of an anharmonic vibrational model and prove to be quite sensitive to the values of the deformation parameters. For forward angles the 4 + angular distributions of ss,6~ are dominated by a L=4 single excitation mechanism. This is in keeping with the E4-transitions observed in (e, e') scattering. From the 2i ~-and 3 +-results transition rates are derived which can be compared to results of electromagnetic methods and of inelastic proton scattering studies. The comparison indicates that the transition rates differ and are generally higher for the proton scattering. Especially in the case of the 3-states of ss,6~ the differences are obvious.The elastic cross sections are analyzed both on the basis of the usual phenomenological model and in terms of a semimicroscopic folding model resulting in values of rms-radii for the nuclear matter distribution.

Experimental studies of hexadecapole motion in spherical nuclei

“…In the case of 6 0 Ni the experiments continue previous studies of elastic andinelastic scattering of 104 MeV a-particles on even Ni isotopes (Rebel et al 1972 a) and improve the accuracy of the 4t cross section. The measurements used the scattering facilities at the 104 MeV a-particle beam at the Karlsruhe Isochronous Cyclotron.…”

“…In these cases from previous investigations (Morinaga and Takahashi 1959, Crannel et al 1961, Rebel et al 1972a, Baker,and Tickle 1972, Pitthan 1973) enhanced hexadecapole transitions are expected to be possibly observable in the direct electromagnetic decay of the 4t states. In addition to the electromagnetic studies and supplementing previous results Rebel 1975b, Rebel 1976)we investigated also the excitation of the 4t states by inelastic scattering of 104 MeV a-particles and extracted the isoscalar L=4 transition rates by procedures which are extensively described elsewhere (Rebel 1976).…”

“…Inelastic electron-, proton-and a-particle scattering have been proved to be very fruitful methods looking for such L=4 contributions. In particular, inelastic a-particle scattering in the 100 MeV region (Tamura 1965, Rebel et al 1972a, Rebel et al 1972 is extremely sensitive to magnitude and phase of L=4 transition amplitudes. Recently, improved and nearly model independent procedures have been worked out (Rebel 1976) for extracting reliable values of the transition rates from a-particle scattering.…”

“…The excitation of the low-lying states is described by a flexible anharmonic vibrational model (Tamura 1966, Rebel et al 1972 describing surface vibrations in the usual way by…”

Microscopic optical potentials forHe4scattering

“…Figure 1 shows dσ/dΩ as a function of transfer momentum q for 4 He+ 58 Ni scattering in E in /A P = 20-175 MeV. For lower incident energies of E in /A P = 20-60 MeV, the DF-FDA model (dotted line) overestimates the experimental data [39][40][41][42], but this problem is solved by the DF-TDA model (solid line) that well reproduces the data. For higher energies around E in /A P = 175 MeV, meanwhile, the DF-FDA model underestimates the experimental data [43], but this problem is also solved by the DF-TDA model that reproduces the data.…”