用4.5MV静电加速器开展快中子照相的研究

用国产原材料研制了一种适用于快中子照相的关键部件——快中子转换屏。利用⁹Be(d，n)反应在北京大学4.5MV静电加速器上产生低于7MeV能区的快中子，采用胶片成像法进行了快中子照相的初步实验。借助带不同孔径的Fe等不同材料制作的不同厚度的试验样品，对快中子胶片成像法的基本性能进行了初步测试和研究。实验结果表明，研制的快中子转换屏能够满足快中子照相的需要。

Research on Fast Neutron Radiography With 4.5 MV Van de Graaff Accelerator of Peking University

The fast neutron converter,which is vital for fast neutron imaging,is produced with the materials made in China.A preliminary experiment is conducted with(direct)-film method under the condition that fast neutron with energies lower than 7 MeV is generated by the reaction of ~9Be(d,n) on the Peking University 4.5 MV Van de Graaff.Basic characteristics of direct-film neutron radiography system is researched with the help of samples in different materials,different thickness and holes of different diameter.The result indicates that fast neutron converter can meet the requirment of fast neutron imaging;what's more,further research of fast neutron imaging can be conducted on the accelerator and neutron-generator in China.