Neutron radiation detector for nuclear reactor applications plays an important role in getting information about the actual neutron flux. Such a detector must be able to operate at high neutron flux levels (>109 cm−2 s−1) and discriminate the neutron and gamma responses in the nuclear reactor’s mixed neutron–gamma environment. Silicon carbide and diamond are the most attractive semiconductor materials for neutron detection, thanks to their outstanding properties, such as high displacement threshold energy and wide bandgap energy, which allow them to operate in high radiation levels and high temperature. The aim of this article is to compare the ability to detect thermal neutrons of these two semiconductors at the same irradiation conditions. For this purpose, the neutron irradiation tests of detectors were implemented at MINERVE research reactor at CEA Cadarache. The 4H-silicon carbide (SiC) p+n diode has demonstrated better neutron–gamma discrimination at 0-V bias voltage than at −200 V which is explained by its increased sensitivity to gamma photons at −200 V caused by a wider charge collection region than at 0 V. Therefore, it is preferable to use the 4H-SiC p+n diode without an external electric field for applications in the mixed neutron–gamma environment such as nuclear reactor environment. The results show that the single-crystal chemical vapor-deposited (sCVD) diamond-based detector has better neutron to gamma discrimination, thanks to the use of 6Li as a neutron converter instead of 10B. However, the study of the radiation stability of detectors showed that the sCVD diamond-based detector suffers from the “polarization effect” when it operates at a high neutron flux (~109 cm $^{-2}\,\,\cdot \,\,\text{s}^{-1}$ ).

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碳化硅和金刚石在室温下进行热中子探测的比较

用于核反应堆应用的中子辐射探测器在获取有关实际中子通量的信息方面发挥着重要作用。这样的探测器必须能够在高中子通量水平 (>109 cm-2 s-1) 下运行，并区分核反应堆中子-伽马混合环境中的中子和伽马响应。碳化硅和金刚石是中子探测中最具吸引力的半导体材料，这要归功于它们出色的特性，例如高位移阈值能量和宽带隙能量，使它们能够在高辐射水平和高温下工作。本文的目的是比较在相同辐照条件下检测这两种半导体的热中子的能力。以此目的，探测器的中子辐照试验是在 CEA Cadarache 的 MINERVE 研究堆中进行的。4H-碳化硅 (SiC) p+n 二极管在 0-V 偏置电压下比在 -200 V 下表现出更好的中子 - 伽马辨别力，这是由于更宽的电荷收集导致其对 -200 V 下的伽马光子敏感性增加区域比 0 V。因此，最好使用没有外部电场的 4H-SiC p+n 二极管，用于混合中子 - 伽马环境（如核反应堆环境）中的应用。结果表明，由于使用 6Li 代替 10B 作为中子转换器，基于单晶化学气相沉积 (sCVD) 金刚石的探测器具有更好的中子对伽马识别能力。然而，