氘核中子反应截面的法捷耶夫方程理论计算

Calculation of Neutron Induced Nuclear Reaction on Deuteron with Faddeev Equation

  • 摘要: 中子引起的轻核反应是核数据研究的重要内容。当前我国核数据库中氘核中子反应截面的计算结果局限于采用s波可分离势,且入射能量在20 MeV以下。需要发展三体核反应的法捷耶夫方程理论方法,采用超出s波的核子核子相互作用,从而对更高能量范围内氘核全套中子反应截面做出准确的描述。本文介绍了利用法捷耶夫方程计算n+d三核子反应体系的弹性散射微分截面、破裂反应、破裂反应出射中子和质子的双微分截面的理论框架及数值计算结果,同时计算了弹性散射总截面和破裂反应总截面的激发函数。计算结果与实验数据及CENDL3.2、ENDF/BⅧ.0、JENDL5、JEFF3.3等数据库中的评价数据符合较好。

     

    Abstract: Neutron induced nuclear reaction on light nuclei is an important subject in nuclear data research. The reaction of the n+d three nucleons system is also an important platform for examining the nucleonnucleon interaction theories. The progress on calculations of neutron induced nuclear reactions on deuterons with the FaddeevAGS equations was introduced in this paper. The equations were solved with the wave packet continuum discretization method in momentum space. The calculated results include the angular distributions of elastic scattering, doubledifferential cross sections of the emitting neutrons and protons from breakup reactions, excitation functions of the total elastic scattering cross sections, and the excitation function of the total breakup reaction cross sections. The elastic scattering cross sections were calculated with the separable Paris nucleonnucleon interaction for incident energy below 20 MeV and with the Nijmegen potential for incident energy above 20 MeV. A comparison between results with the Paris potential, which consists of both s and pwave nucleonnucleon (NN) interactions, and those with the swave Yamaguchi potential for the n+d elastic scattering suggest that NN interactions that are beyond the swave are necessary to describe the experimental data, especially at higher incident energy. Due to practical reasons, calculations of the breakup cross sections, namely, the double differential cross sections of the emitting neutrons and protons are limited with a separable swave Yamaguchitype nucleonnucleon interaction, which limited the calculation of the double differential cross sections to below 20 MeV. Fair agreements are found between the results in this paper and the experimental data and with the evaluated data in CENDL3.2, ENDF/BⅧ.0, JENDL5, and JEFF3.3.

     

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