Fast neutron detector based on TimePix pixel device with micrometer spatial resolution
Fast neutron detector based on TimePix pixel device with micrometer spatial resolution
复制标题
基于微米级空间分辨率的TimePix像素器件的快速中子探测器
DOI：
10.1117/12.830075
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
J. Uher
中科院分区：
文献类型：
--
作者：
J. Jakubek;J. Uher
快中子在许多领域的应用越来越广泛。传统的快中子探测器体积较大，空间分辨率较低。在本文中，我们提出了一种新的检测技术的基础上跟踪质子反冲快中子。跟踪由硅像素化检测器Timepix [1]（300 um厚的硅传感器，256 × 256平方像素，间距为55 um）执行，覆盖富氢转换器（例如塑料材料）。TimePix设备用于检测质子等高度电离粒子的性能已经发表[2]。该技术利用电荷共享效应，并且它基于对单个记录轨道（簇）的适当分析。被快中子反冲的质子的范围通常大于像素大小，从而不仅可以确定能量和位置，还可以确定撞击角度（对于5 MeV质子，精度优于2度）。质子在到达Si传感器之前在塑料中损失了部分能量。如果使用带有硅光电倍增管（SiPM）的塑料闪烁体，则可以测量该能量。这两个设备（SiPM和Timepix）可以同时工作，大大减少了不需要的背景辐射。有了关于反冲质子的所有信息并知道中子的原始方向，就有可能重建转换器中中子-质子碰撞的确切位置和原始中子能量。中子位置测量的最终空间分辨率达到亚像素级（约20 μm）。对于10 MeV中子，预期的能量分辨率约为0.5 MeV。初步的实验结果。
Fast neutrons are increasingly used in many fields. Fast neutrons are conventionally detected by scintillators with relatively large volume and low spatial resolution. In this paper we present a novel detection technique based on tracking of protons recoiled by fast neutrons. The tracking is performed by the silicon pixelated detector Timepix [1] (300 um thick silicon sensor, 256 × 256 square pixels with 55 um pitch) covered by a hydrogen rich converter (e.g. plastic material). The performance of the TimePix device for detection of highly ionizing particles such as protons was already published [2]. The technique utilizes the charge sharing effect and it is based on proper analysis of individual recorded tracks (clusters). The range of protons recoiled by fast neutrons is often greater than the pixel size allowing to determine not only energy and position but also the impact angle (precision is better than 2 degrees for 5 MeV protons). Protons lose part of their energy in the plastic before reaching the Si sensor. This energy can be measured if a plastic scintillator with an attached silicon photomultiplier (SiPM) is used. The two devices (SiPM and Timepix) can be operated in coincidence reducing significantly the undesired background radiation. Having all information about the recoiled proton and knowing the original direction of the neutron it is possible to reconstruct the exact position of the neutron-proton collision in the converter and the original neutron energy. The final spatial resolution of the neutron position determination reaches the subpixel level (about 20 μm). The expected energy resolution is about 0.5 MeV for 10 MeV neutrons. Preliminary experimental results are presented.