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Yang, Jianqing,Zhou, Jianrong,Zhang, Lianjun,Tan, Jinhao,Jiang, Xingfen,Zhou, Jianjin,Zhou, Xiaojuan,Hou, Linjun,Song, Yushou,Sun, XinLi,Zhang, Quanhu,Sun, Zhijia,Chen, Yuanbo Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.7
The <sup>n</sup>MCP (Neutron sensitive microchannel plate) combined with advanced readout electronics is widely used in energy selective neutron imaging because of its good spatial and timing resolution. Neutron detection efficiency is a crucial parameter for the <sup>n</sup>MCP. In this paper, a mathematical model based on the oblique cylindrical channel and elliptical pore was established to calculate the neutron absorption probability, the escape probability of charged particles and overall detection efficiency of <sup>n</sup>MCP and analyze the effects of neutron incident position, pore diameter, wall thickness and bias angle. It was shown that when the doping concentration of the <sup>n</sup>MCP was 10 mol%, the thickness of <sup>n</sup>MCP was 0.6 mm, the detection efficiency could reach maximum value, about 24% for thermal neutrons if the pore diameter was 6 ㎛, the wall thickness was 2 ㎛ and the bias angle was 3 or 6°. The calculated results are of great significance for evaluating the detection efficiency of the <sup>n</sup>MCP. In a subsequent companion paper, the mathematical model would be extended to the case of the spatial resolution and detection efficiency optimization of the coating <sup>n</sup>MCP.
Jiang, Xingfen,Xiu, Qinglei,Zhou, Jianrong,Yang, Jianqing,Tan, Jinhao,Yang, Wenqin,Zhang, Lianjun,Xia, Yuanguang,Zhou, Xiaojuan,Zhou, Jianjin,Zhu, Lin,Teng, Haiyun,Yang, Gui-an,Song, Yushou,Sun, Zhiji Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.6
Gadolinium oxysulfide (GOS) is regarded as a novel scintillator for the realization of ultra-high spatial resolution in neutron imaging. Monte Carlo simulations of GOS scintillator show that the capability of its spatial resolution is towards the micron level. Through the time-of-flight method, the light output of a GOS scintillator was measured to be 217 photons per captured neutron, ~100 times lower than that of a ZnS/LiF:Ag scintillator. A detector prototype has been developed to evaluate the imaging solution with the GOS scintillator by neutron beam tests. The measured spatial resolution is ~36 ㎛ (28 line pairs/mm) at the modulation transfer function (MTF) of 10%, mainly limited by the low experimental collimation ratio of the beamline. The weak light output of the GOS scintillator requires an enormous increase in the neutron flux to reduce the exposure time for practical applications.
Zhu Jingtao,Liu Yang,Zhou Jianrong,Yang Zehua,Zhu Hangyu,Zhou Xiaojuan,Tan Jinhao,Cui Mingqi,Sun Zhijia 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.9
Neutron conversion detectors that use 10B-enriched boron carbide are feasible alternatives to 3 He-based detectors. We prepared boron carbide films at micron-scale thickness using direct-current magnetron sputtering. The structural characteristics of natural B4C films, including density, roughness, crystallization, and purity, were analyzed using grazing incidence X-ray reflectivity, X-ray diffraction, X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry, and scanning electron microscopy. A beam profile test was conducted to verify the practicality of the 10B-enriched B4C neutron conversion layer. A clear profile indicated the high quality of the neutron conversion of the boron carbide layer.
Yang Wenqin,Zhou Jianrong,Yang Jianqing,Jiang Xingfen,Tan Jinhao,Zhu Lin,Zhou Xiaojuan,Xia Yuanguang,Yu Li,Wang Xiuku,Teng Haiyun,Li Jiajie,Qiu Yongxiang,Shen Peixun,Wang Songlin,Wei Yadong,Song Yusho 한국원자력학회 2024 Nuclear Engineering and Technology Vol.56 No.7
Energy-resolved neutron imaging is an effective way to investigate the internal structure and residual stress of materials. Different sample sizes have varying requirements for the detector’s imaging field of view (FOV) and spatial resolution. Therefore, a dual-mode energy-resolved neutron imaging detector was developed, which mainly consisted of a neutron scintillator screen, a mirror, imaging lenses, and a time-stamping optical fast camera. This detector could operate in a large FOV mode or a high spatial resolution mode. To evaluate the performance of the detector, the neutron wavelength spectra and the multiple spatial resolution tests were conducted at CSNS. The results demonstrated that the detector accurately measured the neutron wavelength spectra selected by a bandwidth chopper. The best spatial resolution was about 20 μm in high spatial resolution mode after event reconstruction, and a FOV of 45.0 mm × 45.0 mm was obtained in large FOV mode. The feasibility was validated to change the spatial resolution and FOV by replacing the scintillator screen and adjusting the lens magnification.