快中子诱发核裂变瞬发中子谱高能段核乳胶法测量技术研究

It is well known that the development of nuclear energy has a close relationship with nuclear physics research. However, because of the complexity of the fission system and the physical process, the understanding of people for fission physical theory is not deep, and it remains to be continued to carry out research in this area. It is one of the important issues to explore the method for measuring the prompt fission neutron spectrum in high-energy, which aims at providing accurate experimental data and providing an important basis for verifying or further improving on theory mode of nuclear fission(Such as Los Alamos multi-mode fission). But the data of this sort is still lacking due to the experimental measurement of technical difficulties. It has the potential advantages to apply nuclear emulsion method combined with computer automatic interpretation technology and microscopy the automatic reading technology for the track of the nuclear emulsion in the high-energy of fission prompt neutron spectrum. Nuclear emulsion has unique advantages of very high energy resolution and easy to use. This project is the first time to measure the prompt fission neutron spectrum in high-energy and explore the measurement in this area by using nuclear emulsion. It is helpful for the academic issue and actual application with the accurate data and measurement methdod of the promtp fission neutron spectrum in the high-energy.

核能发展与核裂变物理研究密切相关。但由于核裂变系统和物理过程的复杂性，人们对裂变物理的理论认识其实还不深，仍有待继续深入开展相关研究工作。而探索核裂变瞬发中子谱高能段测量方法，提供精确的实验数据，为进一验证或改进核裂变理论模型（如洛斯阿拉莫斯-多模式裂变模型等）提供重要的实验依据，是当前核裂变物理迫切需要解决的重要问题。但由于实验测量技术上的困难，目前这方面的数据还很缺乏。由于应用计算机并结合显微镜自动扫描判读技术，实现了对核乳胶径迹的自动判读，使得核乳胶在测量低能量中子诱发核裂变产生的瞬发中子谱高能段数据时有潜在的优势。核乳胶具有对高能中子的能量分辨率高、使用方便的独特优点。本项目首次应用核乳胶测量裂变瞬发中子谱高能段数据，探索裂变瞬发中子谱高能段测量方法，提供高精度的裂变瞬发中子谱高能段中子数据，具有重要的学术意义和应用价值。

核能发展与核裂变物理研究密切相关，但由于核裂变系统和物理过程的复杂性，人们对裂变物理的理论认识其实还不深，仍有待继续深入开展相关研究工作，而探索核裂变瞬发中子谱高能段测量方法，提供精确的实验数据，可以为进一步改进核裂变理论（如洛斯阿拉莫斯-多模式裂变模型等）提供重要的实验依据。本项目的研究目的是利用核乳胶探索核裂变瞬发中子谱高能段测量方法。在开展本项目研究工作的过程中，我们利用本单位有多种单能中子源的优势条件，开展了单能中子与核乳胶质子径迹长度的实验标定和理论计算研究；然后开展了用核乳胶测量中子诱发238U裂变的瞬发中子谱高能段数据的实验；用多模式裂变理论结合洛斯阿拉莫斯裂变模型（即多模式-洛斯阿拉莫斯模裂变型）计算了238U裂变瞬发中子谱数据，并与实验测量结果进行了比较。研究表明：由于核乳胶径迹长度数据读出分辩值小（～1m），因此中子能量越高，乳胶中质子径迹越长，测量的能量分辨率越高，另外利用核乳胶测量使用方法简单、对中子场的干扰影响小，是裂变瞬发中子谱高能段测量非常有实用价值的方法之一。