Reduced transition strengths of the deexciting transitions from the first two excited states in Ar33 were measured in a relativistic Coulomb excitation experiment at the GSI Helmholtz center. The radioactive ion beam was produced by fragmentation of a primary Ar36 beam on a Be9 target followed by the selection of the reaction product of interest via the GSI Fragment Separator. The Ar33 beam hit a secondary Au197 target with an energy of approximately 145 MeV/nucleon. An array of high-purity germanium cluster detectors and large-volume BaF2 scintillator detectors were employed for γ-ray spectroscopy at the secondary target position. The Lund-York-Cologne Calorimeter was used to track the outgoing ions and to identify the nuclear reaction channels. For the two lowest energy excited states of Ar33 the reduced transition strengths have been determined. With these first results the Tz=-3/2 nucleus Ar33 is now, together with Na21 (Tz=-1/2), the only neutron-deficient odd-A sd shell nucleus in which experimental transition strengths are available. The experimental values are compared to results of shell-model calculations which describe simultaneously mirror-energy differences and transition-strength values of mirror pairs in the sd shell in a consistent way.
ASJC Scopus subject areas
- Nuclear and High Energy Physics