【作者】 赵新辉；

【导师】 刘林茂；

【作者基本信息】 东北师范大学 ， 核技术及应用， 2006， 硕士

【摘要】 基于无损检测的毒品爆炸物探测技术正越来越受到世界各国的关注,该项技术已成为反恐、禁毒的重要工具。由于中子检测法可以对被检物品进行元素分析,加之中子的强穿透力,利用中子技术进行毒品爆炸物检测有着很大的优势,特别是脉冲快热中子分析(PFTNA)技术的发展,使对毒品爆炸物中多种元素诸如C、H、O、N等的定量分析技术更为成熟。 为以中子发生器为中子源的毒品爆炸物检测系统设计一套合理的中子准直装置,不仅可以减少周围物体对测量结果的干扰,同时对整套系统的辐射防护也有着重要的意义。 Monte Carlo方法能够逼真地描述随机事件并模拟实验过程,特别适用于其本身就具有随机性的粒子输运问题的计算,该方法已被广泛地应用到了包括中子探测的各种核实验的模拟。MCNP是美国阿拉莫斯(Los Alamos)国家实验室利用Monte Carlo思想开发的一套模拟核实验的通用程序,特别适合粒子输运问题的计算。 本文中作者利用MCNP 3B程序对实验中毒品爆炸物检测系统的中子准直装置进行了模拟计算,结果显示:对14MeV中子首先采用金属钨进行慢化,然后外层选取碳化硼质量百分含量8%～10%的含硼聚乙烯慢化材料,可以有效的慢化吸收中子;作者设计的圆柱模型和球模型中14MeV中子沿轴向和径向的变化规律相同,但在准直孔中子计数和相对中子强度变化上圆柱模型要优于球模型。更多还原

【Abstract】 Non-intrusive inspection technology of drugs and explosives detection is getting more and more attention of countries all over the world. This technology has been a vital tool in combating terrorism and banning drugs. Because neutron detection method can analyze the elements of goods being detecting and neutron has strong penetrating force, it has a lot of predominance to use neutron technology in drugs and explosives detection. Especially with the development of the PFTNA technology, it makes more efficient the technology of quantitative analysis of the elements such as C, H, O, N etc. in drugs and explosives.It is helpful to design a suitable neutron collimation device of drugs and explosives detection system which use neutron generators as neutron sources. The device can not only reduce the effect of objects around but also benefit the radiation defence of the whole system.Monte Carlo Method can realistically describe the random events and simulate the experiment courses. It is very suitable for the calculation of particle transport problem which has the randomicity. The method has been widely used in the simulation of nuclear experiments include neutron detection. MCNP is a general program to simulate nuclear experiments, which is made by Los Alamos Station Lab in America based the Monte Carlo thoughts.In the article the author used the MCNP 3B program to simulate and calculate the neutron collimation device of drugs and explosives detection system. The results show that the tungsten and the polythene with 8%~10% B4C by weight are good moderator material of 14MeV neutrons and variety rules of 14MeV neutrons along and apeak the axis are uniform between the column model and the sphere model, but the column model is superior to the sphere model in neutron counts at collimation hole and the relatively intensity of neutrons.更多还原