A Detailed Study of Pre-scission γ Emission as a Probe of Nuclear Dissipation

摘要

＜正＞ Using a Langevin equation coupled with a statistical model,we calculate pre-scission giant dipole resonance（GDR） γ-ray multiplicity of nuclei 194pb,200Pb,206Pb,and 200Os.It is demonstrated that with increasing the isospinasymmetry of these fissioning nuclei the sensitivity of the emitted γ multiplicity to the nuclear viscosity coefficient isdecreased significantly.For 200Os nucleus,this γ-ray emission is no longer sensitive to the magnitude of the viscositycoefficient.In addition,the effect of the isospin asymmetry on the γ rays as a probe of nuclear dissipation is reducedwith increasing angular momentum.These results suggest that to obtain a more accurate information of the viscositycoefficient by the measurement of pre-scission GDR γ-ray multiplicity it is better to choose those compound systemswith small isospin asymmetry and low spin.