Joint multiplicity distribution of neutrons and charged products in the reaction Bi+Xe at E/A=28.2 MeV

For the first time, both neutrons and charged products have been measured with almost complete solid-angle coverage for an intermediate-energy heavy-ion reaction. The joint particle multiplicity distribution shows that charged-product emission becomes significant only for neutron multiplicities larger than 20. This distribution exhibits a distinct ridge, whose position can be reproduced by simulation calculations assuming sequential evaporation from the primary products of a binary collision. It has been deduced from the light-particle multiplicities that only about 60% of the energy available in the entrance channel can be converted to excitation energy of the primary fragments. This value is confirmed by the observed average velocities of light-particle emitters. Information on the degree of correlation between excitation energy and multiplicities of particles is deduced from the joint multiplicity distribution