Gamma ray spectroscopy of exotic nuclei: physics and tools

Radioactive beams obtained via fragmentation of the projectile on a primary target have shown to be a powerful tool to produce exotic nuclei. Some typical results obtained at GANIL in this area will be shown. To go further and, in particular, to get beams of exotic nuclei, new facilities have been developed recently. The physics case expected from the use of these radioactive ion beam facilities is extremely ambitious as stated in the scientific motivations justifying their construction. At GANIL, the SPIRAL facility is ready and will hopefully deliver the first radioactive beams before the end of 2000. However, when looking into more details, it soon appears that severe limitations might reduce the hopes if R and D efforts are not done. The low intensities, wide range of experimental conditions and the radioactive nature of the beam itself are some of these constraints. The design of the future (and already under construction) spectrometers intended to be used with radioactive beams integrates these new difficulties in their technical specifications. In this talk, based on the description on some simple realistic experiments, the physics will be described and the performances expected from the new generation of detectors will be discussed. The trends for new ideas in large efficiency spectrometers will be briefly described, based on the experience which has already been acquired through the R and D performed in the framework of some large collaborations. (author)