高产额紧凑型中子发生器研制

Compact neutron generator based on D-D and D-T reaction plays an important role in the following potential research fields, such as the real-time neutron activation analysis,fast neutron radiography，the detection of explosive and other neutron application technology .Study on the technology of compact neutron generator is still in the initial stage in China. In this plan, a compact neutron generator with high neutron yield (greater than 1.0e9 n/s for D-D and greater than 1.0e11 n/s for D-T) will be developed by preparing key elements, such as RF ion source with higher D beam, a well cooled target system. In addition, focus on the problem that the target is located at a negative high potential end in the compact neutron generator, an associated particle monitor system will be developed for neutron yield measurement with a high measurement accuracy（the measurement uncertainty: ≤5% for D-D, ≤3% for D-T）

基于D-D和D-T反应的紧凑型中子发生器在实时在线中子活化分析、快中子照相、爆炸物检测及其它中子应用领域有广泛的应用前景，而我国在紧凑型中子发生器技术研究方面相对滞后。本项目拟通过内置天线高频（RF）离子源、靶系统等关键技术的研究，研制一台高产额紧凑型中子发生器，使D-D中子产额大于1.0E9 n/s，D-T中子产额大于1.0E11 n/s。另外，针对紧凑型中子发生器靶处于负的高电位端的特殊问题，将通过二次电子抑制、并排除其它粒子的干扰等关键问题研究，发展用于中子产额测量的伴随粒子测量系统，实现高产额紧凑型中子发生器快中子产额的准确测量，使D-D和D-T快中产额测量的不确定度分别达到小于5%和3%。

在国家自然科学基金项目支持下，成功研制了一台紧凑型中子发生器，中子发生器外形为圆柱状，其长为980mm，直径为280mm，氘（D）束流能够被加速到200keV能量，轰击氘靶或氚靶通过核反应产生快中子。采用一陶瓷环将靶和引出加速电极绝缘，再在靶和引出加速电极连接一电阻R，当D束流轰击在靶上并通过流经电阻R时，即可在靶和引出加速电极之间形成一偏置电压，利用此偏置电压可以很好地抑制靶上二次电子的反加速。另外，还发展了一套用于快中子产额和能谱测量的EJ309液体闪烁体探测系统。在使用一个纯金属钼自注入靶、氘束流参数为200keV和4mA条件下，D-D中子产额达到了1.2×109n/s。取得的其他成果为发表学术论文7篇，获授权专利2件（其中美国专利1件），获软件著作权2件。