基于光腔衰荡光谱法的大面积负离子源负离子产生特性研究  

Characteristics of negative ion generation in large area negative ion source based on cavity ring-down spectroscopy

作　　者：朱腾赛 梁立振[1,2] 谢亚红 曹正坤[1,2] 彭旭峰 胡纯栋 ZHU Tengsai;LIANG Lizhen;XIE Yahong;CAO Zhengkun;PENG Xufeng;HU Chundong(Hefei Institutes of Physical Science,Chinese Academy of Sciences,Hefei 230031,China;University of Science and Technology of China,Hefei 230026,China)

机构地区：[1]中国科学院合肥物质研究院,合肥230031 [2]中国科学技术大学,合肥230026

出　　处：《核技术》2025年第1期185-191,共7页Nuclear Techniques

基　　金：国家重大科技基础设施建设项目:聚变堆主机关键系统综合研究设施(No.2018-000052-73-01-001228)资助。

摘　　要：光腔衰荡光谱(Cavity Ring-down Spectroscopy,CRDS)是一种灵敏度很高的吸收光谱测量技术。根据该技术在大面积负离子源上的需求,研制了基于负离子光致剥离的CRDS诊断系统,开展了负离子产生相关特性研究。本文首先详细介绍了CRDS装置的运行原理和构成,然后利用该系统开展了射频功率、源腔气压和偏置电压等不同实验参数下对氢负离子产生的特性研究。实验结果表明:射频功率和源腔气压的升高都会引起氢负离子的增多,由于两者变化对电子温度产生的不同影响,氢负离子的增长速率在两者影响下的变化情况相反;由于等离子体电位的存在,偏置电压存在一个有利于氢负离子产生的最优值。[Background]The neutral beam injection system(NBI)has the highest heating efficiency and the clearest physical mechanism,so it has become one of the main auxiliary heating methods used in the world's large magnetic confinement controlled thermonuclear fusion devices.The application of NBI system based on negative ion source is increasingly demanding and urgent.Cavity ring-down spectroscopy(CRDS)is a highly sensitive absorption spectrum measurement technique with relatively simple principle,and the measurement results are not limited by electromagnetic field interference and other plasma parameters.[Purpose]This study aims to explore the characteristics of negative ion generation in negative ion source based on CRDS,and measure negative ion density produced by NBI.[Methods]First of all,a CRDS diagnostic system was developed on a large area negative ion source.Then the related characteristics of negative ion production was investigated by sequentially measuring the decay time of pulsed laser in front of the plasma electrode plate under different experimental parameters.Finally,developed CRDS diagnostic system was employed to study the characteristics of hydrogen anion generation under different experimental parameters,such as radio-frequency(RF)power,source pressure and bias voltage.[Results]Experimental results show that produced negative hydrogen ions increase with the increase of RF power and pressure in the source cavity.Due to the different effects of the two changes on the electron temperature,the growth rate of negative hydrogen ions changes opposite under the influence of different power and pressure.There is an optimal value of bias voltage that is conducive to the generation of negative hydrogen ions because of the plasma potential.[Conclusions]Application of CRDS-based measurement approach in this study provides valuable experience for further research on the generation of negative hydrogen ions and the beam quality.

关 键 词：负离子源 光腔衰荡光谱 衰荡时间 氢负离子密度 电子温度 

分 类 号：TL65+7[核科学技术—核技术及应用]