Fragmentation of 95 MeV/u 12C and 75 MeV/u 13C.: Application to secondary-beam production

The fragmentation of 95 MeV/u C-12 and 75 MeV/u C-13 projectiles, interacting with natural targets of different elements (Be-9, Cu-nat and Au-197 for C-12, and Be-9, Ni-nat, and Ta-181 for C-13) and of various thicknesses has been investigated at GANIL, using the doubly achromatic magnetic spectrometer LISE. The projectile-like fragments transmitted at 0degrees have been analysed using a silicon DeltaE-E telescope and the DeltaE-time-of-flight method. The results obtained with the thinnest targets are discussed in the scope of radioactive nuclear beam production. The fragment momentum distributions can be fitted by Gaussian peaks associated with exponential tails towards low momentum values. The experimental production yields are compared with the results of the simulation code LISE. It appears that this code reproduces satisfactorily the yields of nuclei close to the stability line, but strongly overestimates the production of very neutron-deficient nuclei.