IEC-based neutron generator for security inspection system
IEC-based neutron generator for security inspection system
复制标题
用于安全检查系统的基于 IEC 的中子发生器
DOI：
10.1115/icone10-22696
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
G. Miley
中科院分区：
文献类型：
--
作者：
Linchun Wu;G. Miley
大型核反应堆广泛用于发电，但小型核辐射源也可用于各种工业/政府应用。本文将讨论基于惯性静电约束（IEC）的加速氘离子小中子源的使用。迫切需要高效的爆炸物探测系统，特别是在机场。虽然目前的机场检查系统主要以x射线技术为基础，但中子活化，包括热中子分析（TNA）和快中子分析（FNA），在检测行李和货物中的某些类型的爆炸物方面非常有效。通过快中子引发的（n, n′γ）反应，可以测定炸药中存在的基本元素。结合飞行时间技术，获得了关键元素的完整成像，从而获得了爆炸物的完整成像。在各种中子源发生器中，IEC是满足中子活化分析要求的理想选择。与其他加速器和放射性同位素（如252cf）相比，IEC更简单，可以打开或关闭，并且可以可靠地产生中子，维护最少。在伊利诺伊大学进行了球形IEC的理论和实验研究。在球形IEC装置中，近年来通过DD反应获得的~ 108 n/s的2.54-MeV中子或通过DT反应获得的~ 2×1010 n/s的14-MeV中子可以使用离子枪注入技术获得。本文还讨论了柱形IEC在脉冲工作模式下与脉冲FNA方法相结合的可能性。在本文中，我们研究了使用替代圆柱形IEC配置的可能性。伊利诺伊大学早些时候研究过这种装置，它为安全检查提供了非常方便的几何形状。然而，要用这种结构精确地计算中子产率，需要了解离子的潜在壁捕获和加速。所涉及的理论是R.L. Hirsh对球形IEC装置中势阱结构的原始解析研究的扩展，即大致上，来自圆柱形IEC的“线”中子源是来自球形几何的“点”中子源。因此，为了便于在FNA检测系统中应用，我们将重点研究圆柱形IEC。介绍了用于中子检测系统的圆柱形IEC中离子捕获和再循环的概念设计和物理。ASME版权所有©2002
Large nuclear reactors are widely employed for electricity power generation, but small nuclear radiation sources can also be used for a variety of industrial/government applications. In this paper we will discuss the use of a small neutron source based on Inertial Electrostatic Confinement (IEC) of accelerated deuterium ions. There is an urgent need of highly effective detection systems for explosives, especially in airports. While current airport inspection systems are strongly based on X-ray technique, neutron activation including Thermal Neutron Analysis (TNA) and Fast Neutron Analysis (FNA) is powerful in detecting certain types of explosives in luggage and in cargoes. Basic elements present in the explosives can be measured through the (n, n’γ) reaction initiated by fast neutrons. Combined with a time-of-flight technique, a complete imaging of key elements, hence of the explosive materials, is obtained. Among the various neutron source generators, the IEC is an ideal candidate to meet the neutron activation analysis requirements. Compared with other accelerators and radioisotopes such as 252 Cf, the IEC is simpler, can be switched on or off, and can reliably produce neutrons with minimum maintenance. Theoretical and experimental studies of a spherical IEC have been conducted at the University of Illinois. In a spherical IEC device, 2.54-MeV neutrons of ∼108 n/s via DD reactions over recent years or 14-MeV neutrons of ∼2×1010 n/s via DT reactions can be obtained using an ion gun injection technique. The possibility of the cylindrical IEC in pulsed operation mode combining with pulsed FNA method would also be discussed. In this paper we examine the possibility of using an alternative cylindrical IEC configuration. Such a device was studied earlier at the University of Illinois and it provides a very convenient geometry for security inspection. However, to calculate the neutron yield precisely with this configuration, an understanding of the potential wall trapping and acceleration of ions is needed. The theory engaged is an extension of original analytic study by R.L. Hirsh on the potential well structure in a spherical IEC device, i.e. roughly a “line” source of neutrons from a cylindrical IEC is a “point” source from the spherical geometry. Thus our present study focuses on the cylindrical IEC for its convenient application in an FNA detecting system. The conceptual design and physics of ion trapping and re-circulation in a cylindrical IEC intended for neutron-based inspection system will be presented.Copyright © 2002 by ASME