ISOLDE

About the project

The Oslo group of the ISOLDE-project is involved in experiments studying nuclear collectivity and shapes at the Isotope Separation On-Line facility ISOLDE at CERN, which produces a large variety of post-accelerated radioactive ion beams. In a typical experiment, the isotope of interest is accelerated to an energy of 3 MeV per nucleon by the REX accelerator and then Coulomb excited on a secondary target located inside the Miniball Germanium detector array. The observed Coulomb excitation cross sections allow extracting reduced transition probabilities B(E2) from the excited states and, in favorable cases, spectroscopic quadrupole moments. One of the PhD students in the project, Gry Tveten, was based at the ISOLDE facility and involved in technical developments. Sunniva Siem serves as the Norwegian representative on the Isolde Collaboration Committee (ISCC).

In collaboration with scientists from CEA Saclay, the Oslo group has initiated a research project to study oblate nuclear shapes and shape coexistence in neutron-deficient rare earth isotopes, jointly led by Sunniva Siem and Andreas Görgen (Saclay).

• Letter of Intent (April 2008)
• Experiment proposal (January 2009)
• Presentation at INTC (A. Görgen)

Prior to the above proposal, the Oslo group has been involved in several other ISOLDE experiments:

• Transition strengths in light Sn isotopes, PRL 101, 012502 (2008)
• Coulomb excitation of ⁷⁰Se, PRL 98, 072501 (2007), with a complementary lifetime measurement at INFN Legnaro, PRL 100, 102502 (2008)
• Shape coexistence in ^182,184Hg, (Proposal, under analysis)
• Shape coexistence in neutron-rich Sr isotopes, (Proposal, under analysis)