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Study for Intense Neutrl Helium Bean

强中性氦豆的研究

基本信息

批准号：
10480110
负责人：
SASAO Mamiko
金额：
$ 7.49万
依托单位：
Natiomal Institute for Fusion Science
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-10480110/
关键词：
helium negative ion metastabe helium atom low work function surface alpha particle diiagnostics nuclear fusion hurning experiment アルファ粒子

项目摘要

Diagnostics of fusion-produced-alphas is an important task for a burning plasma experiment. One possible way to obtain the velocity distribution of confined alphas is combination of neutral-particle-analysis with injection of a neutral He beam at the energy of 0.8 MeV/nucleon. To realize this diagnostic method, development of an intense beam source (≧1mA/cm2) of He is important. A compact bucket-type He+ source was developed and a 77 μA dc He" beam was obtained at 11 keV using a Rb double-charge-exchange cell with conversion efficiency better than 3 %. This type of source was further developed by optimizing the extraction system and by operating in the higher discharge power region. A beam more than 20mA/cm2 was extracted from a 0.6 cm-diameter hole at 11 keV. This record provides a promising beam system for alpha particle diagnostics. The electron capture process of He+ into one-electron excited states of a He atom has been studied in prospect of subsequent He" formation. The spectroscopic measurement in a Rb charge exchange cell was performed when a low energy He+ beam of 2 - 10 keV was injected. The ratio of emission lines decaying into triplet states to those into singlet is increased as the impact energy of He+ increases. The results are compared with theoretical calculation using Smirnov method. Searching for a better way to produce He" with less amount of alkali metal consumption, we tested if He" production was possible from a low work function metal surface by injecting a metastable-He neutral beam. The experiment showed that the low work function surface becomes unstable mostly by bombardment of incoming energetic neutrals. Further study is needed to realize an applicable He" beam.The compact bucket source developed here became a reference design for the industrial use.

聚变产物α的诊断是燃烧等离子体实验的一项重要任务。中性粒子分析与注入能量为0.8 MeV/核子的中性He束流相结合，是获得受限α粒子速度分布的一种可能方法。为了实现这一诊断方法，研制一台He的强流束源(≧1 mA/cm~2)是非常重要的。研制了一种小型桶形He+源，利用Rb双电荷交换池在11keV获得了转换效率优于3%的77μA直流He“束流。通过优化引出系统和在较高的放电功率区工作，进一步发展了这种类型的He+源。在11keV下，从一个直径0.6 cm的小孔中引出了大于20 mA/cm~2的束流。这一记录为α粒子诊断提供了一个有前途的束流系统。为了展望后续的He”形成，我们研究了He+原子的单电子激发态的电子俘获过程。在Rb电荷交换池中进行了2-10keV低能He+束流的光谱测量。随着He+入射能量的增加，衰变为三重态的发射线与衰变为单重态的发射线之比增大。将计算结果与Smirnov方法的理论计算结果进行了比较。为了寻找一种更好的方法来用更少的碱金属消耗来生产He，我们测试了是否可以通过注入亚稳态He中性束从低功函数的金属表面生产He。实验表明，低功函数表面主要是由于入射高能中性粒子的轰击而变得不稳定。本文所研制的紧凑型桶形光源为工业应用提供了参考设计。