Mass measurement project by determination of Qβ for neutron-rich nuclei

The aim of the project described hereafter is to collect new data on the exotic neutron rich nuclei of the Fe to Zn region, and in particular to determine their masses, for both nuclear physics and astrophysics purposes. These isotopes will be produced through projectile fragmentation at the GANIL facility and selected by the LISE3 spectrometer. Their half-lives will be measured as well as the energy of their main γ rays; γ - γ coincidences will then allow to build a preliminary level scheme. The analysis of β spectra and β - γ coincidences will finally provide the maximum β decay energies of the studied nuclei leading to their masses. The difficulties arising from the low production rates, the β detection, the data handling are discussed together with the solutions proposed to overcome them. (authors). 17 refs