摘要
随着第四代核反应堆和新型核能利用系统的快速发展,以及超重核熔合机制和天体核物理中的快中子俘获反应等领域的研究进展,使得中子诱发重核裂变研究及裂变数据测量成为国际上核物理研究的新热点。本工作完成了基于速度-动能法的中子诱发裂变谱仪的物理设计。设计了MCP二次电子时间探测器,二次电子飞行时间展开控制在50 ps,TOF长度设计为70 cm。选择屏栅电离室为能量探测器,工作气体选择为异丁烷,最佳约化场强为6 V/(cm·133.32 Pa),气压为5000 Pa。采用COMSOL、Geant4、Garfield++等程序耦合计算了裂变碎片在屏栅电离室中的能量响应,谱仪系统的能量分辨率为0.36%~0.55%。本工作设计的基于速度-动能法的中子诱发裂变谱仪,当轻裂变碎片能量分辨率小于0.8%,重裂变碎片小于0.6%时,裂变碎片的质量分辨小于1 amu。此外,基于设计的裂变谱仪物理结构,本工作模拟计算了14 MeV中子诱发^(238)U裂变产额质量分布与电荷分布数据,与ENDF-VII基本一致,为中子诱发典型锕系重核裂变物理实验测量准备了条件。
With the rapid development of fourth-generation nuclear reactors and new nuclear energy utilization systems,as well as advancements in research areas such as superheavy nucleus fusion mechanisms and fast neutron capture reactions in astrophysical nuclear physics,neutron-induced heavy nucleus fission studies and fission data measurements have become a significant topic of international nuclear physics research.In this study,we present the physical design of a neutron-induced fission spectrometer using the velocity-kinetic energy(v-E)method.The MCP secondary electron time detector was designed with the spread of secondary electron flight time controlled at 50 ps,and the TOF flight distance was designated for 70 cm.For the energy detection,we selected the Frisch-Grid Ionization Chamber(FGIC)with isobutane as the working gas.The optimal reduced electric field was 6 V/(cm·133.32 Pa),and the optimal pressure was 5000 Pa.The energy response of the fission fragments in chamber was calculated by coupling programs such as COMSOL,Geant4,and Garfield++,and the energy resolution is from 0.36%to 0.55%.The fission spectrometer designed in this work has a mass resolution of less than 1 amu,provided that the energy resolution of light fragments is less than 0.8%and that of heavy fragments is less than 0.6%.Additionally,based on the physical structure of the fission spectrometer,the mass distribution and charge distribution data of^(238)U fission yield induced by 14 MeV neutron are simulated in this work,which is basically in agreement with the ENDF-VII,preparing the conditions for experimental measurements of neutron-induced fission physics of typical actinide heavy nuclei.
作者
马骏
李明
张鹏琦
白晓厚
吴康
于筱雪
韩亚宁
张时宇
姚泽恩
张宇
王俊润
韦峥
MA Jun;LI Ming;ZHANG Pengqi;BAI Xiaohou;WU Kang;YU Xiaoxue;HAN Yaning;ZHANG Shiyu;YAO Zeen;ZHANG Yu;WANG Junrun;WEI Zheng(School of Nuclear Science and Technology,Lanzhou University,Lanzhou 730000,China;Research Center for Neutron Application,Ministry of Education,Lanzhou University,Lanzhou 730000,China;MOE Frontiers Science Center for Rare Isotopes,Lanzhou University,Lanzhou 730000,China)
出处
《原子核物理评论》
北大核心
2025年第2期279-287,共9页
Nuclear Physics Review
基金
国家自然科学基金资助项目(U2167203,12435018)
中子科学与技术全国重点实验室项目(NST202401016)
中国核工业集团有限公司-兰州大学核燃料循环与核技术国家研究院项目(CNNC-LCKY-2024-085)
甘肃省重大科技项目(22ZD6GB020)
中央高校基本科研业务费专项资金项目(lzujbky-2023-stlt01,lzujbky-2025-jdzx11)。
