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.