Nuclear Structure Studies

We study the stucture of exotic, very neutron-rich nuclei in the mass range A=80-160 mostly via gamma-ray and conversion-electron spectroscopy, using a range of experimental facitilies and techniques. The aim of these studies is to test the predictions of different theoretical models (shell model, quasi-particle-rotor, quasi-particle-phonon etc.) in areas far from stability. This allows us to search for any changes in nuclear forces in regions far from stability. Theoretical predictions vary and some of these predict that nucleon-nucleon interactions may change in very neutron-rich nuclei. We are also trying to understand the roles played by different orbitals in rapidly changing nuclear shapes. These experiments have taken place at a range of facilities including the LOHENGRIN fission fragment spectrometer (shown below) and PF1B neutron guide of the ILL Grenoble, ISOLDE (Isotope Separator On Line) at CERN, GANIL, GSI-FAIR and RIKEN. These experiments usually require the participation of some tens of physicists as part of international collaborations. Currently the subject of nuclear-structure studies is undergoing a renaissance due to the construction of new radioactive-beam factilities such as SPIRAL-2 (where the accelerator and ion-source groups of the LPSC play an active role in its construction), HIE-ISOLDE, FAIR, RIBF and FRIB which allow, or will soon allow, the structure of the most exotic nuclei to be probed. We are currently involved in developing fast-timing detectors for these radioactive-beam facilities, as part of the international FATIMA collaboration. In addition we also use, test and develop different theoretical models of the atomic nucleus.

Ligne faisceau LOHENGRIN à l'ILL
The LOHENGRIN fission-fragment spectrometer of the ILL