A.D. Panagiotou

Nuclear structure of light nuclei using the selectivity of high energy transfer reactions with heavy ions

Abstract We present data obtained by bombarding light nuclei with beams of 11B, 12C and 14N at energies of about 10 MeV/nucleon. Reactions involving transfers of various numbers of nucleons were investigated and the spectra of the detected ions correspond to a wide range of excitation energies in the residual nuclei. The results characteristically show only a few strong peaks in each spectrum and the cross sections exhibit many of the features of direct reactions. We explain the apparent high degree of selectivity in terms of the interplay of reaction mechanisms and the structure of the strongly populated states. Firstly, it is shown that a simple semiclassical model of the reaction process indicates that states of the final nucleus with high spin are greatly favoured. On the other hand, it is demonstrated that the shell-model gives a reasonably complete explanation for the occurence of such high spin states at the appropriate excitation energies. These shell-model states are found to be dominated by configuration with the structure of a multi-nucleon cluster, in the ground state of its internal motion, orbiting the core nucleus so that the centre of mass motion of the cluster carries all the excitation quanta.

The Masses of 51Ca and 47Ar

Transfer reactions with beams of 14C on a target of 48Ca were used to measure the masses of 51Ca and 47Ar. A natural Ca target was used to estimate the background due to impurities in the 48Ca target. In the case of 47Ar this is the first reported measurement, but in the case of 51Ca the results do not corroborate a previous experiment.

Structure of states in 20Ne from the reactions 18O(11B, 9Li)20Ne and 16O(11B, 7Li)20Ne

Abstract The failure to observe the 4 + and 6 + states at 10.8 and 12.56 MeV in 20 Ne in the 18 O( 11 B, 9 Li) 20 Ne reaction indicates that these states are (pf) 4 rather than (sd) 2 (pf) 2 . States seen in the 16 O( 11 B, 7 Li) 20 Ne reaction are also interpreted.

Heavy-ion transfer reactions on 208Pb above the coulomb barrier

Abstract The selective excitation of single-particle and hole states in stripping and pick-up reactions induced by 11 B ions of 113.5 MeV on 208 Pb is interpreted on the basis of a semi-classical theory. The excitations of outgoing ions and the continuum are also discussed.