Study on physics mechanism of vacuum discharge toward electrostatic accelerator of the energy higher than 1 MeV

1 MeV以上能量静电加速器真空放电物理机制研究

• 批准号: 18560807
• 负责人: INOUE Takashi
• 金额: $ 1.38万
• 依托单位: Japan Atomic Energy Agency
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2006
• 资助国家: 日本
• 起止时间: 2006 至 2007
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-18560807/
• 关键词: Accelerator; Plasma; Vacuum discharge; Vacuum insulation; Clump theory; Triple junction; Organic insulation material; X線

Using a MeV accelerainr being developed for neutral beam injector ofITER, experiments on vacuum insulation have been carried out to establish physics and engineering basis toward general purpose electrostatic accelerator of the beam energy more than 1MeV.● A large bore FRP (glass fiber reinforced epoxy) insulator was tested its applicability toward the accelerator of more than 1MeV. Prevention of surface flashover was demonstrated by reducing the stress at cathode side triple junction (interface of vacuum metal and dielectric insulator) below 1kV/mm.● Data base on vacuum insulation was established for a range of vacuum gap width in real accelerator geometries.(1) Achievable voltage as a function of gap length seems to follow to Clump theory(2) Achievable voltages in the real accelerator geometries are about a half of that achieved with a quasi-ideal Rogowsky electrode, even the vacuum gap length were the same in both cases.(3) The deterioration of voltage holding in the real accelerator geometries are probably due to local electric field concentration in the accelerators, such as corner of the grid support or junction between grids and grid support structures.● Extrapolation of achievable voltage in the accelerator at various gas pressure suggests possibility of vacuum and glow discharge prevention even the voltage was 2MV by maintaining the pressure at 0.02Pa, though necessary vacuum gap length would be as long as 2m.

利用正在研制的ITER中性束注入器MeV加速器，进行了真空绝热实验，为束流能量大于1 MeV的通用静电加速器的研制奠定了物理和工程基础。通过将阴极侧三重结（真空金属和绝缘体的界面）处的应力降低到1 kV/mm以下来防止沿面闪络。●建立了真实的加速器几何结构中真空间隙宽度范围内的真空绝缘数据库。(1)（2）在真实的加速器几何结构中的可击穿电压大约是用准理想Rogowsky电极实现的可击穿电压的一半，即使真空间隙长度在两种情况下是相同的。(3)真实的加速器几何结构中电压保持的恶化可能是由于加速器中的局部电场集中，例如栅极支撑的拐角或栅极与栅极支撑结构之间的接合处。●在各种气体压力下加速器中可实现的电压的外推表明，通过将压力保持在0.02Pa，即使电压为2 MV，也可以防止真空和辉光放电，尽管必要的真空间隙长度将长达2 m。

项目成果

ITER NBI用SINGAP-MAMuG加速器の性能比較試験

ITER NBI SINGAP-MAMuG加速器性能对比测试

• 发表时间: 2009
• 期刊: 日本原子力研究開発機構研究開発報告書JAEA-Research 2008-121
• 作者: 谷口正樹;柏木美恵子;梅田尚孝;大楽正幸;渡遁和弘;井上多加志;Hubert de Esch;Lennart Svensson
• 通讯作者: Lennart Svensson

Development of 1MeV accelerator and HV bushing at JAEA toward ITER Neutral Beam system(web公開済)

JAEA 针对 ITER 中性束系统开发 1MeV 加速器和高压套管（在线发布）

• 发表时间: 2009
• 期刊: Fusion Engineering and Design (印刷中)
• 作者: N. Umeda;M. Taniguchi;M. Kashiwagi;M. Dairaku;M. Hanada;H. Tobari;K. Watanabe;K. Sakamoto;T. Inoue
• 通讯作者: T. Inoue

High energy, high current accelerator development for ITER NBI at JADA

JADA 为 ITER NBI 开发高能、高电流加速器

• 发表时间: 2008
• 作者: M. Kashiwagi;M. Taniguchi;M. Dairaku;H. P. L. de Esch;L. R. Grisham;L. Svensson;H. Tobari;N. Umeda;K. Watanabe;K. Sakamoto;T. Inoue
• 通讯作者: T. Inoue