补偿中子测井中与温度相关轻水热中子散射数据库的研制与应用

补偿中子测井受到环境温度的影响,利用数值模拟计算来进行修正,但目前的理论计算程序MCNP缺乏水的精细温度相关的热中子散射数据库。为了解决蒙特卡罗模拟热中子散射S(α,β)模型只能求解特定温度条件下中子输运问题的局限性,基于热中子散射的S(α,β)原理,采用内插法得到不同温度下水的频谱分布、振动;在最新的ENDFB-VII.1数据库上,利用NJOY99程序制作了ACE格式的轻水热中子散射截面数据库。利用系列次临界基准题对数据的准确性进行了验证,不同数据库之间的计算结果及基准题的结果符合得很好。自制的数据应用于测井仪器中的温度效应修正,取得了较好的效果。     

快中子照相胶片成像法的初步实验

利用9Be(d,n)反应在北京大学4.5MV静电加速器上产生小于7MeV能区的快中子,采用胶片法进行了快中子照相的初步实验.对快中子胶片成像法的基本性能进行了初步的测试和研究.用国产的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.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.A preliminary experiment is conducted with direct film method under the condition that fast neutron is generated by the reaction of 9Be (d,n) on the Peking University 4.5 MV Van de Graff, whose energy is lower than 7 MeV.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 fast neutron converter, which is vital for fast neutron imaging, is produced with the materials made in china. 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.