A Background-Free Direction-Sensitive Neutron Detector
A Background-Free Direction-Sensitive Neutron Detector
复制标题
无背景方向敏感中子探测器
DOI：
--
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发表时间：
2009
影响因子：
1.8
通讯作者：
H. Wellenstein
中科院分区：
文献类型：
--
作者：
S. Ahlen;D. Dujmić;P. Fisher;A. Inglis;H. Tomita;H. Wellenstein
中子性质的探测和测量在许多研究领域都非常重要，包括中子散射和射线照相术、太阳和宇宙射线中子通量的测量、中子相互作用截面的测量、核设施中子监测、石油勘探和大规模杀伤性裂变武器的搜索。许多中子探测器受到来自X射线和伽马射线的大背景的困扰，并且大多数当前的中子探测器缺乏单事件能量灵敏度或关于中子方向性的任何信息。即使是最好的探测器也会受到宇宙射线中子背景的限制。所有应用都将受益于改进的中子探测灵敏度和改进的中子性质测量。在这里，我们展示了一种新型探测器的数据，这种探测器可以用来确定中子通量、能量分布和中子运动方向。探测器不受X射线、伽马射线、β粒子和相对论性单电荷粒子的背景影响。它对宇宙射线中子相对不敏感，因为它们有独特的角分布和能量分布。它对热中子、裂变谱中子和高能中子敏感，每种能量范围的探测特征都不同。它能够根据中子被氦核弹性散射的特性确定裂变中子源的位置。便携式探测器可以在1米远的地方识别1克反应堆级钚，观察时间不到1分钟。
The detection and measurements of properties of neutrons are of great importance in many fields of research, including neutron scattering and radiography, measurements of solar and cosmic-ray neutron flux, measurements of neutron interaction cross sections, monitoring of neutrons at nuclear facilities, oil exploration, and searches for fissile weapons of mass destruction. Many neutron detectors are plagued by large backgrounds from X-rays and gamma rays, and most current neutron detectors lack single-event energy sensitivity or any information on neutron directionality. Even the best detectors are limited by cosmic ray neutron backgrounds. All applications would benefit from improved neutron detection sensitivity and improved measurements of neutron properties. Here, we show data from a new type of detector that can be used to determine neutron flux, energy distribution, and direction of neutron motion. The detector is free of backgrounds from X-rays, gamma rays, beta particles, and relativistic singly charged particles. It is relatively insensitive to cosmic ray neutrons because of their distinctive angular and energy distributions. It is sensitive to thermal neutrons, fission spectrum neutrons, and high-energy neutrons, with detection features distinctive for each energy range. It is capable of determining the location of a source of fission neutrons based on characteristics of elastic scattering of neutrons by helium nuclei. A portable detector could identify 1 g of reactor grade plutonium 1 m away with less than 1 min of observation time.