Preliminary Experimental Study on Parameters of Conduct for Neutron Photography Based on Reactors

Based on the available thermal neutron beam of In-hospital Neutron Irradiator (IHNI), a collimator was designed and constructed for the purpose of neutron radiography. The diameter of the collimator entrance was 4 or 2 cm while the exit was 10 cm. The most collimation ratio was 58 and the divergence angle was 4.1°. The parameters of the neutron beam were studied by experiments. At full power of IHNI, the neutron fluence rate at the exit of the collimator is 1.0×10⁶cm^-2•s^-1, while the average γ dose rate is 11.65 mSv/h, which could meet the requirement of neutron radiography.