高灵敏度的快中子照相系统

快中子照相系统由闪烁光纤阵列和科学级可见光CCD等元件组成. 14 MeVD-T聚变中子在穿透样品后进入50 mm×50 mm闪烁光纤阵列，中子辐射转换为中心波长496 nm的绿光. 光纤阵列长100 mm，光纤截面500 μm×500 μm，100×100根闪烁体光纤组成阵列. 阵列对14 MeV中子探测效率经估算可达21.4%. CCD与光纤阵列之间采用反射镜和透镜耦合方式，使CCD避开中子源直接辐照. 综合考虑光纤尺寸、CCD记录噪声及中子源与受照样品几何关系等因素，理论上系统可获得整体分辨率1.5 mm的中子图像. 在K400直流加速器中子源上进行了初步实验，获得了中子图像.

High-sensitivity fast neutron radiography system

Introduced in this paper is a fast neutron radiography system, which is mainly composed of a scintillation fiber array and a scientific grade optical CCD. The 14 MeV neutrons produced by deuterium-tritium fusion reactions, penetrate through objects and fall into a 50 mm×50 mm scintillation fiber array, and the neutron radiation is converted to green light (496 nm). The array has a length of 100 mm, consisting of 100×100 square scintillation fibers each with a cross-section of 500 μm×500 μm. For 14 MeV neutrons, the detection efficiency is as high as 21.4%. To avoid direct radiation from neutrons, the CCD is coupled to the array by a mirror and lens optics. By taking into account the factors affecting image quality, the resolution is estimated to be 1.5 mm. Several neutron radiographs have been obtained successfully in experiments carried out on K400 neutron generator.