基于反应堆中子照相孔道参数初步实验研究

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

摘要: 在医院中子照射器反应堆现有的水平热中子孔道的基础上，设计了一个适用于中子照相的热中子准直器。准直器入口2 cm或4 cm，出口直径为10 cm，长度为115 cm，最大准直比为58，偏移角为4.1°。对设计的热中子孔道进行了初步实验研究，结果显示，满功率运行时准直器出口处热中子注量率为1.0×10⁶ cm^-2•s^-1，γ本底剂量率平均为11.65 mSv/h，达到了热中子照相的要求。

Abstract: 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.