Development of Sophisticated Fusion Neutron Measurement System Based on Optical Fiber Sensing

本研究的目的是建立一种基于光纤传感技术的聚变中子测量系统的新概念，在该系统中，从光的传播时间，光吸收率和光发射点对向立体角等参数，设计并制作了原型系统，对原型系统的基本性能进行了实验验证，主要研究成果如下：（1）设计并实验验证了一种简单、紧凑的聚变中子测量系统，该系统采用多级塑料散射光纤和一对位置灵敏光电倍增管，能同时测量中子的能量和入射方向（或剖面）。(2)A利用有机液体闪烁体与波长漂移光纤相结合，设计并实验验证了一种大灵敏面积的聚变中子图像传感器。（3）基于实验结果开发了模拟程序来估计上述探测器性能，并用于改进和/或优化探测器系统设计。（4）这些结果已应用于类似ITER聚变等离子体诊断的概念设计方案，特别是聚变中子剖面监测器的新概念。

The purpose of this study is to create a new concept of sophisticated fusion neutron measurement system based on optical fiber sensing technique, where deposited energy and position of fusion neutrons incident onto a network consisting of organic optical fibers and scintillators with different characteristics are measured three-dimensionally and simultaneously from light propagation time, light absorption rate and solid angle subtended by light emission point in the network components.We have designed and partially manufactured the prototype system for experimental demonstration of their basic performances.Main achievements in this study are summarized as follows :(1)A simple and compact fusion neutron measurement system which can obtain energy and incident direction (or profile) of neutrons simultaneously has been devised and experimentally demonstrated by using multistage plastic scintillating fibers combined with a pair of position sensitive photomultipliers.(2)A fusion neutron image sensor with a large sensitive area has been devised and experimentally demonstrated by combining organic liquid scintillator with wavelength shifting fibers.(3)The simulation program has been developed to estimate the above detector performance based on the experimental results and used to improve and/or optimize the detector system design.(4)These results have been applied to conceptual design proposals for an ITER-like fusion plasma diagnostics, in particular for new concept of fusion neutron profile monitors.