The SPEG mass measurement program at GANIL

The measurement of masses (or binding energy) of nuclei far from stability is of fundamental interest for our understanding of nuclear structure. Their knowledge over a broad range of the nuclear chart is an excellent and severe test of nuclear models. This is why considerable experimental and theoretical efforts have been and are invested in this domain. Here we want to give a description of a direct mass measurements combining high-resolution time-of-flight determinations and accurate momentum measurements in a spectrometer. This very fast and direct method was developed at GANIL with the high resolution spectrometer SPEG. The mass measurements realised and scheduled provide important first indications of new regions of deformation or shell closures very far from stability. (author)