The yields of neutron-rich fission fragments from the interaction of 20 MeV/nucleon ${}^{238}$U with ${}^{208}$Pb have been measured. The production mechanism of these fragments is consistent with sequential fission following a quasielastic or deep inelastic collision. Substantial yields of very n-rich fragments are observed. The importance of these data for generation of n-rich radioactive beams by fission of intermediate-energy projectiles is discussed.

• Received 25 February 1997

DOI:https://doi.org/10.1103/PhysRevC.55.R2146