S. Thummerer

Spectroscopy of exotic nuclei with multi-nucleon transfer reactions

Structure investigations of neutronrich helium isotopes and of10Li and11Be have been performed using multi-nucleon transfer reactions. New results have been obtained for7He He, where we have evidence for the observation of the first excited state, i.e. the 1/2-resonance, which is of interest for the spin-orbit splitting in these light neutronrich nuclei. Our results on8He,9He and10He are briefly summarized. Reactions of distinct selectivity have been chosen to study the states of10Li. The structure of the eight states found in these reactions is discussed, as well as their relevance for the decay of11Li resonances. The isotopes10Be and11Be have been investigated to study the a-cluster structure and high-lying states. Nine states of the observed11Be-resonances can be characterized as a molecular rotational band extending up to 25 MeV excitation energy, with a probable maximum spin of 19/2. The reaction mechanism is studied in terms of two-step calculations, where protons are picked-up from the target and neutrons are transferred to the target. Using measured strength amplitudes for the single steps results in a quantitative description of the observed two-step cross sections.

Search for12C+12C molecule in24Mg* populated by24Mg+12C

The gamma-decay properties of 24Mg excited states are investigated in the inverse reaction 24Mg+12C at E(24Mg) = 130 MeV. At this energy the direct inelastic scattering populates a 24Mg* energy region where 12C+12C breakup resonances can occur. Very exclusive data were collected with the Binary Reaction Spectrometer (BRS) in coincidence with EUROBALL installed at the VIVITRON Tandem facility of the IReS at Strasbourg. The experimental detection system is decribed and preliminary results of binary reaction coincid data are presented.

Structure of neutron-rich Be and C isotopes

The structure of neutron-rich beryllium isotopes has been investigated using different heavy-ion-induced transfer reactions. In neutron transfer reactions, the population of final states shows a strong sensitivity to the chosen core nucleus, i.e., the target nuclei 9Be or 10Be, respectively. Molecular rotational bands up to high excitation energies are observed with 9Be as the core due to its pronounced 2α-cluster structure, whereas only a few states at low excitation energies are populated with 10Be as the core. For 11Be, a detailed investigation has been performed for the three states at 3.41, 3.89, and 3.96 MeV, which resulted in the most probable spin-parity assignments 3/2+, 5/2−, and 3/2−, respectively. Furthermore, we have studied particle-hole states of 16C using the 13C(12C, 9C)16C reaction and found 14 previously unknown states. Using the 12C(12C, 9C)15C reaction, five new states were observed for 15C.

Fission decay of N = Z nuclei at high angular momentum: Zn-60

Using a unique two-arm detector system for heavy ions (the BRS, binary reaction spectrometer) coincident fission events have been measured from the decay of

Gamma-decay study of 21Na and 21Ne, octupole bands in 21Ne

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Structure studies of 11Be and 12Be: Observation of molecular rotational bands

Zn compound nuclei formed at 88MeV excitation energy in the reactions with

ALPHA-CLUSTER STATES POPULATED IN 24Mg + 12C

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Spectroscopy of Ne, Na and Mg isotopes approaching the Island of Inversion

Ar beams on a

In-beam γ-ray spectroscopy with binary reactions using the HMI binary reaction trigger spectrometer

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Binary reaction decays from 24Mg + 12C

Mg target at