We have measured production yields and longitudinal momentum distributions of projectilelike fragments in the reaction Xe+Al at an energy of =790 MeV. Production cross sections higher than expected from systematics were observed for nuclei in the neutron-deficient tails of the isotopic distributions. A comparison with previously measured data from the fragmentation of Xe ions shows that the production yields strongly depend on the neutron excess of the projectile with respect to the line of stability. The momentum distributions exhibit a dependence on the fragment neutron-to-proton ratio in isobaric chains, which was not expected from systematics so far. This can be interpreted by a higher excitation of the projectile during the formation of neutron-deficient fragments.
- Received 20 January 1998
©1998 American Physical Society