Fast neutron resonance radiography for elemental imaging: Theory and applications
Fast neutron resonance radiography for elemental imaging: Theory and applications
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DOI：
10.1109/tns.2002.801696
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发表时间：
2002-08-01
影响因子：
1.8
通讯作者：
Lanza, RC
中科院分区：
文献类型：
--
作者：
Chen, GY;Lanza, RC
快中子共振成像(NRR)是一种元素成像方法，具有违禁品检测和矿物分析等应用。在NRR中，氢、碳、氮、氧和其他元素的总和的二维(2-D)元素图是从快中子照相图像中获得的，这些图像在不同的中子能量下拍摄，并被选择来覆盖一个或多个元素的共振截面特征。图像是使用透镜耦合塑料闪烁体电荷耦合器件(CCD)组合而成的。在初步实验中，我们用基于Li(p，n)Be反应的变能束和变能质子束产生了各种模拟物的NRR图像。作为这种方法的一种替代方法，我们研究了在固定入射D能量下利用D-D反应d(d，He)n的NRR成像，并利用中子能量的角变化扫描了不同的中子能量。物体和探测器一起绕着中子源旋转，可以在与目标不同的角度获得不同能量(2-6 MeV)的中子。射线照相传输图像提供元素含量总和的2-D映射(由衰减系数加权)。然后，在不同的中子能量(角度)下进行的透射率测量形成一组线性方程，然后可以求解这些方程来绘制单个元素的含量图。
Fast neutron resonance radiography (NRR) has been devised as an elemental imaging method with applications such as contraband detection and mineral analysis. In NRR, a two-dimensional (2-D) elemental mapping of hydrogen, carbon, nitrogen, oxygen, and the sum of other elements is obtained from fast neutron radiographic images, taken at different neutron energies and chosen to cover the resonance cross-section features of one or more elements. Images are formed using a lens-coupled plastic scintillator charged coupled device (CCD) combination. In preliminary experiments, we have produced NRR images of various simulants using a variable energy beam based on the Li(p,n)Be reaction and a variable energy proton beam. As an alternative to this method, we have studied NRR imaging using the D-D reaction, d(d,He)n, at fixed incident D energy and scanning through various neutron energies by using the angular variation in neutron energy. The object and detector rotate together around the neutron source; different energy (2-6 MeV) neutrons can be obtained at different angles from the target. The radiographic transmission image provides a 2-D mapping of the sum of elemental contents (weighted by the attenuation coefficients). Transmission measurements taken at different neutron energies (angles) then form a set of linear equations, which can then be solved to map individual elemental contents.