γ probe of nuclear dissipation

The Langevin model is applied to investigate the roles of excitation energy and system size in the evolution of post-saddle giant dipole resonance (GDR) gamma-ray multiplicity (M-gamma) with post-saddle friction strength (beta). It is demonstrated that M-gamma is more sensitive to beta at high energy. Furthermore, it is shown that the dependence of gamma emission on friction is sensitive to the size of fissioning nuclei, and a large system size significantly increases the sensitivity. Our findings indicate that in experiments, to tightly constrain post-saddle dissipation through the gamma probe, it is optimal to produce heavy fissioning systems with high energy.