Gamma-ray spectroscopy at GANIL

Full text: The coupling of very efficient gamma-ray arrays with large acceptance (or highly selective) spectrometers has pushed away the limits and opened up new possibilities in nuclear physics studies. This is the case at GANIL with the setting up of EXOGAM (a large efficiency gamma-ray array) coupled to VAMOS (a large acceptance spectrometer). In this talk, the various possibilities offered at GANIL with such a coupling will be given. In particular, this powerful coupling allows to exploit radioactive beams providing that the required precautions have been cautiously considered. At GANIL radioactive beams can be produced either via the fragmentation technique or via the ISOL method. Two examples of experiments using EXOGAM+VAMOS, the first one exploiting an ISOL beam and the second one a high energy beams from fragmentation, will be described. Another asset of GANIL is the availability of intense heavy beams like uranium. The use of inverse kinematics optimises the efficiency of the spectrometer and allows the search for very weakly populated channels. This technique has been used with the aim to access very exotic Ca isotopes around N=34. Finally, radioactive beams produced via the fragmentation technique are also available at GANIL. This allows the study of far off stability, short-lived nuclei produced with sometime very low intensity but also limited background. Examples of the physics around the closed shells using this kind of beam will be shown. In the longer term, the SPIRAL2 project will be built at GANIL. This new generation of ISOL facility will deliver intense beams of very exotic species. The future facility will be described and the associated physics programme discussed. (author)