^(151)Eu中子俘获截面中^(152)Eu同质异能态贡献的模型检验和分析

Model calculation and analysis of ^(151)Eu neutron capture cross section contributed by isomeric state of ^(152)Eu

^(151)Eu中子俘获截面在反应堆物理以及核天体物理慢中子俘获过程中具有重要的作用,由于^(152)Eu两个同质异能态(m1, 0-; m2, 8-)的贡献,使得生成^(152)Eu基态和同质异能态的中子俘获截面的测量和区分难度增大。利用核反应理论模型程序—TALYS-1.8,计算了中子能量在0.01~20 MeV区间的^(151)Eu(n,γ)^(152)Eu基态和同质异能态的中子俘获反应截面,并与EXFOR截面数据库中已有的实验数据进行比较,检验了现有^(151)Eu实验数据的可靠性。分析表明:由于^(152)Eu基态和第一同质异能态都存在121.8 keV能级的退激,使得它们的截面测量存在较大误差,而基态和第二同质异能态的截面理论值基本与实验值相一致。

[Background] The ^151Eu neutron capture cross-section plays an important role in reactor physics and in the slow neutron capture of nuclear astrophysics. [Purpose] This study aims to distinguish two isomers of ^152Eu and measure neutron capture cross-section of ^151Eu. [Methods] The ^151Eu（n,γ）^152Eu reaction cross-sections at the neutron energies from 0.01 MeV to 20 MeV were calculated by using software TALYS- 1.8 which is a mature computer code for simulating nuclear reactions in present work. The accuracy of simulation calculation program was verified and compared the theoretical data with the existing experimental data from EXFOR cross-section database and the latest neutron activation cross-section data. [Results ＆ Conclusions] The results show that there is a large error in the cross-section measurement of the ground state and the first isomeric state due to the interference of the 121.78 keV energy level, whereas the theoretical values of the ground state and the second isomeric state are basically consistent with the existing experimental values.