%0 Thesis
%A Lepyoshkina, Olga
%T Coulomb Excitation of Proton Rich Nuclei 32Ar and 34Ar
%I Technische Universität München
%V Dissertation
%M GSI-2019-00710
%P XII, 102 S. : Ill., graph. Darst.
%D 2013
%Z Dissertation, Technische Universität München, 2013
%X In the present thesis an investigation of the low-lying strength in the proton-rich nuclei32Ar and 34Ar is reported. The earlier observation of low-lying dipole strengthin neutron-rich nuclei and its interpretation with respect to basic nuclear properties(symmetry energy, skin thickness) initiated the investigation of this phenomenon inproton-rich nuclei. Macroscopically this so-called Pygmy strength could be interpretedwith the resonant dipole oscillation of a proton-skin against an isospin-symmetric core.For nuclei like 32Ar the occurrence of pronounced dipole strength is predicted in the lowenergyregion between 8-10 MeV excitation energy. For the 34Ar the pygmy strengthis expected to drop sharply and vanish entirely for the N=Z nucleus 36Ar. Using theCoulomb excitation method in inverse and complete kinematics at the LAND/R3Bsetup at GSI Helmholtzzentrum f¨ur Schwerionenforschung GmbH in Darmstadt, Germany,an experiment using radioactive 32Ar and 34Ar beams has been performed. Theisotopes were obtained via fragmentation of a 825 AMeV primary 36Ar beam on a6.347g/cm2 Be target. The produced proton-rich projectiles with a similar mass-tochargeratio were separated from the primary beam and from other reaction productsin flight using the Fragment Separator FRS. The selected and identified proton richisotopes with a remaining energy of 650 AMeV were subsequently directed to a leadtarget of the LAND/R3B setup placed in Cave C. In order to determine the excitationenergy after projectile excitation on the Pb target, all the products of the decay fromthe resonance are detected and identified (fragments, protons and gammas). The reconstructionof the excitation energy for one- and two-proton emission channels for 32Arand 34Ar were derived from the particles momenta using the invariant mass techniquein an event-by-event mode, allowing for an investigation of dipole strength appearance.After the experiment, all the detectors have been calibrated and the Coulombdissociation cross section for one and two proton emission were determined with twodifferent techniques, which are in good agreement. The data provide first evidencefor the existence of low-lying dipole strength in 32Ar, while no low-lying strength isobserved in 34Ar. However, further analysis is necessary in order to define the detailsand interpretation of the appearance of the low-lying strength dipole in 32Ar.
%F PUB:(DE-HGF)11
%9 Dissertation / PhD Thesis
%U https://repository.gsi.de/record/218893