加速器中子源比反应堆中子源更具灵活性,北京大学正在发展基于RFQ加速器的小型中子照相装置.为了更好地设计和优化此装置,实现高品质的中子照相,我们在北京大学4.5 MV静电加速器上建立了中子照相实验平台,包括科学级制冷、高灵敏度、低噪声的CCD数字成像系统,模拟基于厚铍靶9Be(d,n)反应RFQ中子源的条件,并利用此系统开展中子成像技术的研究.实验在像平面热中子注量率为5×10^3 cm^-2·s^-1或快中子注量率为3.7×10^4 cm^-2·s^-1的情况下获得了一定质量的热中子及快中子照片.当利用RFQ直线加速器强中子源时将可获得更高质量的图片,从而可以满足大多数的应用需要.
The accelerator neutron source is more flexible than the reactor neutron source. A neutron radiography facility based on a high current RFQ accelerator is under development at Peking University. For the better design of this system and realization of the small convenient accelerator neutron radiography facility in the future, the installation of neutron radiography was built on the 4.5 MV Van de Graaff at Peking University including the eooled-CCD radiography system to simulate the condition of the RFQ source. The research was carded out on this system using the D-Be reaction. The quality photos of thermal neutron and fast neutron radiography have been obtained when thermal neutron's flux is 5×10^3cm^-2·s^-1 or fast neutron's flux is 3.7×10^4 cm^-2·s^-1. When using the RFQ accelerator, the better photos can be obtained.