Low-energy Coulomb excitation of the neutron-rich Mg isotopes _1hn3_1hn0Mg and _1hn3_1hn2Mg [Elektronische Ressource] / presented by Oliver Thomas Niedermaier

Dissertationsubmitted to theCombined Faculties for the Natural Sciences and for Mathematicsof the Ruperto-Carola University of Heidelberg, Germanyfor the degree ofDoctor of Natural Sciencespresented byOliver Thomas Niedermaierborn in RavensburgOral examination: 06.07.2005Low-Energy Coulomb Excitation of the30 32Neutron-Rich Mg Isotopes Mg and MgReferees: Prof. Dr. Dirk SchwalmProf. Dr. Hans EmlingAbstractThe rst \safe" Coulomb excitation experiments with beam energies below the Coulombbarrier have been performed at the newly commissioned radioactive beam facility REX-ISOLDE at CERN in conjunction with the modern HPGe -spectrometer MINIBALL.REX-ISOLDE and MINIBALL o er unique possibilities to study collective and single-particle properties of nuclei far from stability by standard techniques such as \safe"Coulomb excitation and transfer reactions in inverse kinematics.30 32From the Coulomb excitation experiments with beams of Mg and Mg, the reduced++transition probabilities B(E2; 0 ! 2 ) of these isotopes could be extracted in a model-g:s: 12 4 2 4independent way to be 253(21) e fm and 434(52) e fm , respectively. While the B(E2)"30value of Mg is that expected for a pure sd-shell nucleus, the unusually large collective32value observed for the \semi-magic" N = 20 nucleus Mg re ects the vanishing neutronshell gap between sd- and the f -shell con gurations which has been conjectured for the7=232neutron-rich isotopes of Ne, Na and Mg.