薄膜样品中^(10)B原子核数的实验测量

Measurement of the number of ^(10)B nuclei in thin film samples

采用北京大学4.5 MV静电加速器D(d,n)反应产生快中子,通过厚石蜡对中子进行慢化。以6LiF薄膜为标准样品(其中6Li原子核数目已知),使用背对背双屏栅电离室作为带电粒子探测器,同时探测热中子与6Li以及热中子与10B反应产生的t和a粒子。采用相对测量法,得到了待测薄膜样品中10B的原子核数。

By using the relative measurement method, the number of ^10B nuclei in the thin film sample was measured. The experiment was performed at the 4.5 MV Van de Graaff accelerator of Peking University. Neutrons were produced through the D（d,n） reaction and the fast neutrons were moderated by the thick paraffine layer. A ^6LiF sample with definite number of ^6Li nuclei was used as the reference, and a twin gridded ionization chamber was used to detect the tritons from the ^6Li（nth, t）4He reaction and the alpha particles from the ^10B（nth,α）^7Li reaction.