M. Brenner

Observation of an α-cluster structure in 36Ar

Excitation functions for 32S+α elastic scattering are measured by a new method based on inverse kinematics and a thick gas target. Data corresponding to the 36Ar excitation range 12–16 MeV are treated within the R-matrix approach. Spin-parity assignments are given for over 40 new levels.

Narrow states in38,40Ar via alpha +34,36S scattering

Excitation functions of the elastic scattering α+34,36S has been measured at beam energies Eα=12.56–15.00 MeV. Strongly fluctuating large cross sections in backward angles have been observed. Angular distributions were measured in the range θlab=98°–173° for fourteen energies, and many of them turned out to be dominated by one exclusive angular-momentum value, a behaviour typical for resonance scattering.

Cluster states in the neutron excess nucleus 22Ne

High-spin states of the 22Ne nucleus in the excitation energy range of 15–30 MeV have been studied. The angular correlation method has been used to determine the spins of excited states. A number of new states with high angular momenta—20.0 MeV (9−), 20.7 MeV (11−), 21.6 MeV (9−), 22.2 MeV (12+), and 25.0 MeV (9−)—have been revealed. They are intensely populated in the reaction 14C(12C, α1)22Ne* → α2 + 18O and correspond to the rotational bands of various structures.

Search for alpha-particle condensates by scattering and transfer of alpha particles

Alpha-particle condensates are investigated by scattering and transfer of alpha particles on light nuclei.

Aspects of alpha-particle scattering and structure of the nuclear surface

The interaction of α particles above 5 MeV with a 2s-1d target is dominated by resonances. It cannot be described only in terms of a mean-field one-body potential. An analysis of the elastic α-particle scattering by 28Si encourages the comprehension of the resonance states to be mainly fragments of a mixed-parity band. In the present article, the angular distributions of particles scattered by 32S are analyzed in terms of such bands. The analysis of new data from an experiment made at Florida State University reveals the existence of states that do not belong to the above bands. This follows from a coupled-channel analysis of the elastic and inelastic (2+) cross sections. An α-particle structure at the nuclear surface is suggested.

Cluster effects in the angular distribution of alphas scattered from34S

The addition of a resonance scattering contribution to the shape elastic scattering improves the fit in analysing experimental angular distributions. Spins from 7 to 10 ħ characterize the resonances, which have a dominant influence on the six analysed angular distributions of 12.80 to 20 meV alpha particles elastically scattered from34S. The relation between the energy of the resonances and their spin compares well with the results from alpha scattering from28Si. As in the scattering from silicon, the occurrence of a dominating spins supports the assumption that they belong to cluster states formed when alpha particles hit the target nuclei.

High-Resolution Study of α+28Si Elastic Scattering with a Cyclotron-Fragmented α-Cluster States?

The α + 28Si elastic scattering excitation functions at θlab = 43, 50, 82, 118, 148, 163 and 173 degrees have been measured at the cyclotron of the Abo Akademi Accelerator Laboratory in energy steps of 40 keV. The energy resolution of the beam after the analysing magnet was better than 0.1 %. From the excitation function at 173 degrees (fig.l.) it is evident that the elastic cross-section exhibits sharp peaks with widths that seem to be less than or about 70 keV.