激发能相关的能级密度参数和重核衰变性质(英文)
Excitation Energy Dependence of Level-density Parameters and Decay Properties of Heavy Nuclei
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摘要: 基于裂变的随机模型，研究了能级密度参数在鞍点与其基态处的比值af/an在热核衰变过程中的作用。计算表明，af/an的大小能显著影响蒸发剩余截面及其自旋分布的大小以及裂变过程中热核的耗散行为。发现，能级密度参数对激发能的依赖性af/an(E*) 能改变断点处的激发能对摩擦强度的敏感性。最后指出了af/an随E* 的变化对超重核的稳定性和散裂反应退激阶段描述的意义。Based on the stochastic approach to fission, we have demonstrated that the ratio of level-density parameters at saddle to that at ground-state configuration, af/an, plays a significant role in the decay of an excited nucleus. It modifies not only the sensitivity of evaporation residue cross section and its spin distributions
to nuclear friction, but also the dissipation properties of hot nuclei. Furthermore, we find that af/an as a function of excitation energy appreciably affects the evolution of excitation energy at scission with the friction strength. A consequence of a change of af /an with E* on the stability of superheavy nuclei and on modelling de-excitation processes of spallation reactions is indicated.Abstract: Based on the stochastic approach to fission, we have demonstrated that the ratio of level-density parameters at saddle to that at ground-state configuration, af/an, plays a significant role in the decay of an excited nucleus. It modifies not only the sensitivity of evaporation residue cross section and its spin distributions
to nuclear friction, but also the dissipation properties of hot nuclei. Furthermore, we find that af/an as a function of excitation energy appreciably affects the evolution of excitation energy at scission with the friction strength. A consequence of a change of af /an with E* on the stability of superheavy nuclei and on modelling de-excitation processes of spallation reactions is indicated.
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