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复杂聚变中子测量系统的新概念，从光传播时间三维同时测量入射到由不同特性的有机光纤和闪烁体组成的网络上的聚变中子的沉积能量和位置，本文的主要研究成果如下：(1)利用多级塑料闪烁光纤和一对位置灵敏光电倍增管，设计并实验演示了一种简单紧凑、能同时获得中子能量和入射方向(或轮廓)的聚变中子测量系统。(2)将有机液体闪烁体和波长移位光纤相结合，设计并实验演示了一种大灵敏面积的聚变中子图像传感器。)开发了基于实验结果的模拟程序，用于评估上述探测器的性能，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ITER聚变等离子体诊断的概念设计方案，特别是对于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.