  We report here an empirical formalism for predicting the cross-sections of
neutron-rich nuclei produced in fragmentation of relativistic \b{eta}-unstable
neutron-rich projectiles in the mid-mass region. The formalism is based on the
abrasion-ablation picture of the projectile fragmentation reaction. It has been
shown that the formalism can accurately reproduce the experimental
cross-section data for nuclei produced in the fragmentation of 132Sn. The
formalism, it is shown, can also reproduce the experimental cross-sections of
neutron-rich nuclei produced in the fragmentation of 129Xe fairly accurately.
The formalism is used to bring out the advantage in the production
cross-sections of neutron-rich isotopes, especially the more neutron-rich ones;
that one can expect by using unstable doubly magic neutron-rich projectile
132Sn as compared to comparatively less neutron-rich unstable projectile 128Sn
and also 124Sn, the isotope which is most neutron-rich among the stable
isotopes of Sn (tin). The formalism is used to predict the cross-sections of
neutron-rich nuclei produced in the fragmentation reaction of unstable 144Xe
and 146Cs, which are expected to be produced with sufficient intensity in the
upcoming RIB facilities and in the existing RIB facilities after beam intensity
upgrade.
