国产Am-Be中子源能量低于1.5MeV中子所占份额的实验测定  

Experimental Determination of Fraction of Neutrons Below 1.5MeV for Am-Be Neutron Source

作　　者：陈金象[1] 朱培[1] 李永明[1] 刘镇洲[1] 张国辉[1] 

机构地区：[1]北京大学物理学院重离子物理教育部重点实验室,北京100871

出　　处：《原子能科学技术》2008年第5期475-480,共6页Atomic Energy Science and Technology

摘　　要：本工作提出了测定Am-Be中子源发射的能量低于1.5 MeV中子所占份额的1种实用实验方法。用4.438 MeVγ射线伴随的飞行时间法测量了中子源的局部中子谱(n1群中子)。通过已准确测量的中子源发射4.438 MeVγ射线与中子强度的比值(R=Rγ/Sn)和n1群中子谱与测量的能量为1.5 MeV以上中子总谱在3.2 MeV能量处归一后的面积比值,求得国产Am-Be中子源能量低于1.5 MeV中子的所占份额为(19.1±1.9)%。A practical method for experimentally determining the fraction of neutrons below 1.5 MeV for the Am-Be neutron source is described. The partial neutron spectrum （the n1 group） was measured by time of flight accompanied with the 4.438 MeV γ- ray. The fraction of neutrons below 1.5 MeV was derived from the 4. 438 MeV γ-ray to total neutron ratio and the ratio of the area of the n1 group spectrum to the measured total spectrum above 1.5 MeV normalized at the peak near 3.2 MeV. The fraction of neutrons with energies below 1.5 MeV amounts to （19.1±1.9）% for the Chinese-made Am-Be neutron source.

关 键 词：^241Am-^9Be中子源 中子能谱 飞行时间法 

分 类 号：O571.54[理学—粒子物理与原子核物理]