What can we learn from (n,xnγ) cross sections about reaction mechanism and nuclear structure?
What can we learn from (n,xnγ) cross sections about reaction mechanism and nuclear structure?
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我们可以从 (n,xnγ) 截面中了解到有关反应机理和核结构的什么信息？
DOI：
10.1051/epjconf/202023901023
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发表时间：
2020
影响因子：
--
通讯作者：
M. Sin
中科院分区：
文献类型：
--
作者：
M. Kerveno;M. Dupuis;C. Borcea;M. Boromiza;R. Capote;P. Dessagne;G. Henning;S. Hilaire;T. Kawano;A. Negret;M. Nyman;A. Olăcel;Eliot Party;A. Plompen;P. Romain;M. Sin
非弹性(n，n‘)截面是准确模拟反应堆堆芯的关键参数，其精度需要显著提高。为了绕过从(n，xn)反应中探测中子的实验困难，并在裂变靶的情况下区分非弹性散射的中子和遵循裂变过程的中子，使用了一种间接而又强大的方法：瞬发γ-射线光谱学。沿着这条线，我们的合作已经在GELINA设施中开发了字素设置，该设置针对吖系元素进行了优化，以测量部分(n，xnγ)横截面，从该横截面可以推断总的(n，xn)横截面。(n，xn，γ)关于氡系元素的实验仍然特别具有挑战性，因为它们的结构在低能下呈现出高能级密度，而竞争的中子诱发的裂变反应污染了γ的能量分布。新的部分(n，xnγ)截面的精确测量为理论模型提供了严格的检验，并提供了一种改进的方法。这是一条更好地确定总非弹性散射截面的途径。在这篇贡献中，我们讨论了238U和182W(n，n‘γ)反应的建模方面，这些反应也是用字素测量的，使用了三个程序TALYS、EMPIRE和COH。我们将强调在反应建模和核结构输入方面需要/预期的改进。
Inelastic (n,n') cross section is a key quantity to accurately simulate reactor cores, and its precision was shown to need significant improvements. To bypass the experimental difficulties to detect neutrons from (n,xn) reaction and to discriminate inelastically scattered neutrons from those following the fission process in case of fissile targets, an indirect but yet powerful method is used: the prompt γ-ray spectroscopy. Along this line, our collaboration has developed the GRAPhEME setup, optimized for actinides, at the GELINA facility to measure partial (n,xn γ) cross sections, from which the total (n,xn) cross section can be inferred. (n,xn γ) experiments with actinides are still particularly challenging, as their structure presents a high level density at low energy, and the competing neutron-induced fission reaction contaminates the γ-energy distribution. New precise measurements of the partial (n,xn γ) cross sections provide a stringent test to theoretical model and offer a way to improve them. This is a path to a better determination of the total inelastic scattering cross sections. In this contribution we discuss modeling aspects of the 238U and 182W (n,n' γ) reactions, also measured with GRAPhEME, using the three codes TALYS, EMPIRE and CoH. We will highlight the needed/expected improvements on reaction modeling and nuclear structure input.