| 沟槽型硅微结构中子探测器的蒙特卡罗模拟研究 |
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| 引用本文： | 吴健,甘雷,蒋勇,李俊杰,李勐,邹德慧,范晓强.沟槽型硅微结构中子探测器的蒙特卡罗模拟研究[J].强激光与粒子束,2015,27(8):084004. |
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| 作者姓名： | 吴健 甘雷 蒋勇 李俊杰 李勐 邹德慧 范晓强 |
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| 作者单位： | 1.中国工程物理研究院 核物理与化学研究所, 四川 绵阳 621 900; |
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| 摘 要： | 采用蒙特卡罗模拟方法研究了微结构参数、填充致密度等因素对沟槽型微结构半导体中子探测器(MSND)性能的影响规律,并开展了沟槽型MSND的优化设计研究。研究表明,随着沟槽间距的增加,MSND的探测效率呈下降趋势;当沟槽间距固定时,存在最优的沟槽宽度使得探测效率最大化;沟槽深度越大,探测效率越高。沟槽宽度和沟槽间距为15μm和5μm是一对优化的参数组合,可保证较高的探测效率和较平稳的系统甄别阈-探测效率曲线。当系统甄别阈取300keV时,沟槽宽度、间距和深度分别为15,5μm和200μm时的MSND热中子本征探测效率可达37.77%,与平面探测器相比提高了9.2倍;对137 Cs源662keV伽马射线的中子-伽马射线甄别比可达4.1×103,与平面探测器相比提高了23.7倍。本工作从理论上证明了MSND可解决传统平面型半导体中子探测器探测效率低的难题,同时可保持半导体探测器中子-伽马射线甄别容易的特点。
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| 关 键 词： | 微结构中子探测器 中子探测 硅探测器 |
| 收稿时间： | 2015-03-13 |
Monte Carlo simulations of microstructured semiconductor neutron detectors with trench patterns |
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| Affiliation: | 1.Institute of Nuclear Physics and Chemistry,CAEP,Mianyang 621900,China;2.Key Laboratory of Neutron Physics,China Academy of Engineering Physics,Mianyang 621900,China |
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| Abstract: | Microstructured neutron detectors (MSNDs) can achieve a tenfold increase in neutron detection efficiency over the traditional planar detectors. However, the overall detection efficiency is determined by their microstructured features. In this work, we report the influences of microstructured feature and backfilling density on the intrinsic thermal neutron detection efficiency. The design of MSND with trench patterns is optimized. The detection efficiency decreases when the trench gap is increased. The trench width can be optimized when the trench gap is fixed. The detection efficiency increases by increasing the trench depth. MSNDs having trenches with 15 m width and 5 m gap can achieve high detection efficiency and efficiency stability. With the lower level discriminator (LLD) setting at 300 keV, the detection efficiency of MSND with 15 m width, 5m gap and 200 m depth can achieve 37.77% intrinsic efficiency, which is 9.2 times higher than that of the planar semiconductor neutron detectors; The neutron to gamma-ray rejection ratio is 4.1103 for gamma rays of a 137Cs source, which is 23.7 times higher than planar ones. This work demonstrates the outstanding neutron detection efficiency and neutron to gamma-ray rejection ratio of MSNDs with trench patterns. |
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