美国国家点火工程中对条纹X射线探测器的中子辐射防护  

Neutron Radiation Protection for Streaked X-Ray Detector(SXD)Diagnostic in NIF

作　　者：李聪聪[1,2,3] 郭江华[1,3] 聂矗[1,3] 王柱[4] 谢诞梅[1] 

机构地区：[1]武汉大学动力与机械学院核电仿真研究中心,湖北武汉430072 [2]阳江核电有限公司,广东阳江529941 [3]水力机械过渡过程教育部重点实验室,湖北武汉430072 [4]武汉大学物理科学与技术学院,湖北武汉430072

出　　处：《核科学与工程》2013年第3期321-328,共8页Nuclear Science and Engineering

基　　金：湖北省自然科学基金(2010CDB08605;2012FKB04451)

摘　　要：通过建立相关三维模型,利用MCNP程序对激光惯性约束核聚变装置中条纹X射线探测器(SXD)在腔室内受中子辐射的情况进行模拟,并通过聚乙烯(PE)的有效使用对仪器内中子面积分通量进行限制,防止超过仪器的承受范围,以免造成其辐照损伤。通过PE的加入,发现仪器内中子面积分通量有一个数量级左右的减弱,大大延长了SXD的使用寿命,因而在实际使用过程中对X射线的测量精度也有所提高。在之前Peter Song等人的研究中利用TART2002对SXD内的中子及光子面积分通量进行模拟计算,但在相同初始条件下,相比MCNP程序计算的结果误差较大,因此本文利用MCNP程序对SXD进行计算。通过查看Peter Song的文章,发现其并未说明计算中使用的聚乙烯的种类,但是这种密度的聚乙烯有可能是添加了碳化硼或者金属物质的结果,此结论有待验证;而使用本文提到的HDPE作为防护材料较为合理,并且满足安装质量的要求。Streaked X-Ray Detector （SXD） is used in the National Ignition Facility （NIF） to record data for X-ray radiation which can become a reference for photon protection for staffs working closed to the chamber. The MCNP Monte Carlo code isused to simulate the extreme ph ignition process. The equipment fusion is triggered by laser faciliti from extensive neutron radiation. reduced approximately by one ord ysical condition that SXD will undergo during the is located inside the chamber in NIF where inertial es and poly Our er of calcu magnl ethylene （PE） is used to shield the SXD lation indicates that the neutron flux is tude which will extend the ＂lifespan＂ of SXD and that the dose rate of photon is decreased to an acceptable level so that SXD functions better for data recording. In previous simulations, Peter Song and his crews used TART2002 for the same system, but their result turned out to have a larger variance than ours. What we are trying to do is that we recalculate the result using MCNP. By checking Peter Song＇s research, we found out that the type of PE they used in their calculations was not specified throughout the article, by calculating the density of PE, it turned out to be larger than the average density. We assumed that they might have added some kind of boron carbide or metal into the PE, and the result is left to be confirmed. So we use the HDPE as the shielding material which have a smaller density and satisfy the installation requirement in the chamber, making the whole SXD system applicable and operable.

关 键 词：NIF SXD 惯性约束核聚变 中子辐射防护 聚乙烯防护层 

分 类 号：TL76[核科学技术—辐射防护及环境保护]