微通道板高能中子位敏探测器关键技术研究

The traditional digital imaging of High Energy neutron radiography is based on neutron scintillation screen cooperated with CCD camera, whose spatial resolution and neutron detection efficiency is contradictory. Neutron detection method based on microchannel plates (MCP) could solve the problem in traditional method. It could supply high spatial resolution; high neutron detection efficiency and high timing differentiate. Its benefit for high resolution neutron radiography and neutron energy choice imaging..A. S. Tremsin calculated detection efficiency of thermal neutron sensitivity MCP in 2004. Then his team manufactured prototype of neutron detection system based on MCP and carried on neutron imaging experiments at several neutron sources. The Experiments results show that spatial resolution of thermal neutron is nearly 15μm and neutron detection efficiency for cold neutron is more than 70%. In China, Yang Y G from Tsinghua University developed one thermal neutron detection system based on MCP, and preliminary neutron experiment results indicate that spatial resolution is about 200μm..In order to explore a new MCP detector for high energy neutron imaging, we plan to carry out study on follow aspects. firstly, we will study MCP structures themselves as neutron transform part, include material choice and geometry parameters influence to find the optimized structure of MCP. Secondly, we will carry out study on the manufacture of MCPs with sepecial struture. Thirdly, we will carry out study on the readout system, include Wedge-Strip alode readout system and fluorescence screen with fiber wimble coupling CCD detection system. Finally, the encapsulation of whole detectors and high energy neutron imaging experiments will be carried out..With the applying projects, we aim to develop a new high energy neutron detector, which could improve high detection efficiency and high spatial resolution. It could be used for high energy neutron imaging.

基于微通道板（Microchannel Plates）的中子探测技术近年来发展迅速，因其具有高探测效率、高分辨率和优良的时间分辨能力等优点，已用于低能中子照相领域。在中物院发展基金支持下，本课题组开展了微通道板低能中子位敏探测器研究工作，获得低能中子敏感微通道板的优化结构并完成了转换体试制。基于已有研究基础，本课题组拟申请开展微通道板高能中子位敏探测器关键技术研究。拟针对位置灵敏高能中子微通道板转换体的物理设计、高能中子微通道板转换体与读出系统的耦合过程、微通道板高能中子探测器性能影响因素以及微通道板高能中子探测器的实验测试等方面开展研究。将新型高探测效率、高分辨率微通道板高能中子位敏探测器用于高能中子照相，提升其图像质量。

本项目开展微通道高能中子位敏探测器关键技术研究，自项目执行以来，在前期热中子敏感微通道板蒙卡仿真研究基础上，提出了采用含氢材料基底设计并制作高能中子用微通道板的研究思路。先后完成了微通道板参数优化、工艺试制、读出系统研究及探测器封装测试等工作。项目研究攻克了微通道板高能中子位敏探测器的相关技术难点，评估认为研发的微通道板探测器具备中子探测能力及中子的位置分辨能力。.项目首先针对微通道板结构参数进行蒙卡仿真调制，得到了探测效率最优化的高能中子微通道板结构参数。在此基础上进行了含氢材料微通道板的工艺研究，成功得到了含氢材料微通道板基底。通过调研和工艺研究相结合的方式，使含氢材料基底微通道板具备反冲质子发射二次电子能力，以及在高压加载下进行雪崩的能力。项目研究中同步开展微通道板读出系统的研究，针对阳极读出系统和光学收集系统两条技术路线进行了探索，评估认为阳极读出系统和光学收集系统均能够满足探测器需求。项目组利用光学收集系统开展的中子实验测试也表明该读出系统具备中子位敏探测能力。项目研究基本完成了全部研究内容，目前正在进行整体探测器的封装工作。