原子能科学技术 ›› 2022, Vol. 56 ›› Issue (5): 816-824.DOI: 10.7538/yzk.2022.youxian.0189

• 核数据实验测量研究 • 上一篇    下一篇

利用瞬发γ射线法测量209Bi的中子非弹性散射截面

孙琪;王朝辉;张奇玮;黄翰雄;任杰;阮锡超;刘世龙;鲍杰;栾广源;丁琰琰;陈雄军;聂阳波;刘超;赵齐;王金成;贺国珠;杜树斌   

  1. 中国原子能科学研究院 核数据重点实验室,中国核数据中心,北京102413
  • 出版日期:2022-05-20 发布日期:2022-05-20

Measurement of 209Bi Neutron Inelastic Scattering Cross Section with Prompt γ-Ray Method

SUN Qi;WANG Zhaohui;ZHANG Qiwei;HUANG Hanxiong;REN Jie;RUAN Xichao;LIU Shilong;BAO Jie;LUAN Guangyuan;DING Yanyan;CHEN Xiongjun;NIE Yangbo;LIU Chao;ZHAO Qi;WANG Jincheng;HE Guozhu;DU Shubin   

  1. China Nuclear Data Center, Key Laboratory of Nuclear Data, China Institute of Atomic Energy, Beijing 102413, China
  • Online:2022-05-20 Published:2022-05-20

摘要: 在铅铋快堆、空间堆等先进反应堆中,铋作为冷却剂和慢化剂材料被大量使用,其中子核反应截面,尤其是中子非弹性散射截面的准确性对这些核装置的安全性和经济性等具有重要的影响。基于中国原子能科学研究院HI13串列加速器瞬发γ射线实验平台,通过瞬发γ射线法测量了209Bi在90、105和120 MeV 3个能点的中子非弹性散射截面。在相对于中子束30°、70°、110°和150°方向放置4个Clover探测器测量中子与样品相互作用产生的γ射线。实验采用相对测量,通过测量中子与48Ti发生非弹性散射发射的9835 keV γ射线的产生截面来确定209Bi的截面。209Bi金属样品的尺寸为50 mm×4 mm,参考样品为1块50 mm×1 mm的天然钛金属样品。将实验测量结果与已发表的实验数据、ENDF/BⅧ.0、JEFF33、JENDL40、ROSFOND2010和CENDL31等评价库数据以及Talys 195程序默认参数的计算结果进行对比,发现趋势一致,90、105 MeV能点的测量结果与Talys 195程序的计算结果符合得更好,120 MeV能点的测量结果与ROSFOND2010评价库数据符合得更好。 

关键词: 瞬发γ射线法, 氘氘中子源, 飞行时间法, 非弹性散射, 铋, Clover探测器, 相对测量

Abstract: Bismuth is widely used in advanced nuclear reactors such as lead-bismuth eutectic (LBE) fast reactors, space reactors and so on. Its neutron nuclear data, especially the inelastic scattering cross sections have significant impact on safety and economics of these nuclear facilities. A facility for measurement of neutron reaction cross sections using prompt γ ray method based on the HI13 tandem accelerator was established at China Institute of Atomic Energy (CIAE). Neutrons were produced using a D2 gas target bombarded with deuterons at 65, 80 and 95 MeV. The neutron target was positioned in the center of a shielding in size of 2 m×2 m×2 m composed of concrete, iron, lead and borated polyethylene. Neutrons were extracted at 0° with respect to the deuteron beam through a collimator made of copper, iron, polyethylene and lead. Neutron inelastic scattering cross sections at 90, 105 and 120 MeV were measured experimentally for 209Bi with a 209Bi sample in size of 50 mm×4 mm. A natural titanium sample in size of 50 mm×1 mm was used as the reference sample. By measuring production cross sections of the 983.5 keV γ rays produced when neutrons scattered inelastically off 48Ti nuclei, a normalization factor can be determined. 4 Clover detectors were used to measure produced γ rays. They were placed at 30°, 70°, 110° and 150° with respect to the deuteron beam. Lead shielding in thickness of approximately 2 cm was used for detector head to shield scattered γ rays. Timeofflight method was used to determine neutron energy, thus neutrons produced by DD breakup could be discriminated with neutrons produced by DD fusion. The energy and absolute efficiency were calibrated using 152Eu, 60Co, 22Na and 133Ba standard γ sources with known radioactive activities. A 508 cm×508 cm liquid scintillation detector was positioned at the end of neutron beam line to monitor the neutron fluxes passing through the samples. Two specific measurement angles at 110° and 150° were selected to obtain angleintegrated γ production cross sections by performing a simple linear summation of the partial cross sections measured at these angles. Talys 195 code was used to calculate ratios of γ production cross sections and total inelastic scattering cross sections. The experiment results were compared with other experiment data, data retrieved from ENDF/BⅧ0, JEFF33, JENDL40, ROSFOND2010 and CENDL31 evaluated nuclear data libraries as well as calculation by Talys 195 code with the default parameters. The results show that the tendency of these 3 measured energy points is similar to these results. For cross sections measured at 90 and 105 MeV, the results are closer to data calculated with Talys 195 code. For cross section measured at 120 MeV, it fits the ROSFOND2010 evaluated data better.

Key words: prompt γ ray method, D-D neutron source, time-of-flight method, inelastic scattering, bismuth, Clover detector, relative measurement