Role of N/Z in giant dipole resonance γ rays as a probe of post-saddle nuclear dissipation

Using a Langevin model, we calculate the post-saddle giant dipole resonance (GDR) gamma-ray multiplicity of the heavy nuclei Cf-240, Cf-246, Cf-252, and U-240 at various post-saddle dissipation strengths. We find that with increasing the neutron-to-proton ratio N/Z of the Cf system, the sensitivity of the post-saddle gamma emission to the dissipation strength decreases significantly, and it is insensitive to nuclear dissipation for the case of the high N/Z U-240. The results suggest that in experiments to accurately obtain information of the post-saddle dissipation strength by measuring the GDR gamma-ray multiplicity evaporated during the fission process of heavy nuclei, it is best to populate compound systems with low N/Z. (C) 2009 Elsevier B.V. All rights reserved.