Taniguchi M, Mizuno T, Umeda N, Kashiwagi M, Watanabe K, Tobari H, Kojima A, Tanaka Y, Dairaku M, Hanada M, Sakamoto K, Inoue T
Fusion Research and Development Directorate, Japan Atomic Energy Agency, 801-1 Mukoyama, Naka, Ibaraki 311-0193, Japan.
Rev Sci Instrum. 2010 Feb;81(2):02B101. doi: 10.1063/1.3274808.
A multiaperture multigrid accelerator called "MeV accelerator" has been developed for neutral beam injection system of international thermonuclear experimental reactor. In the present work, long pulse H(-) ion beam acceleration was performed by the MeV accelerator equipped with new water-cooled grids. At present, the pulse length was extended to 5 s for the beams of 750 keV, 221 mA, and 10 s for the beams of 600 keV, 158 mA. Energy density, defined as products of beam energy (keV), current (mA), and pulse (s) divided by aperture area (m(2)), increased more than one order of magnitude higher compared with original MeV accelerator without water cooling in its grids. At higher energy and current, the grid was melted by beam deflection. Due to this grid melting, breakdowns occurred between the grids, and hence, the pulse length was limited. Beam deflection will be compensated by aperture displacement in next experiment.
一种名为“兆电子伏加速器”的多孔径多栅加速器已被开发用于国际热核聚变实验反应堆的中性束注入系统。在当前工作中，通过配备新型水冷栅极的兆电子伏加速器进行了长脉冲H(-)离子束加速。目前，对于能量为750 keV、电流为221 mA的束流，脉冲长度延长至5 s；对于能量为600 keV、电流为158 mA的束流，脉冲长度延长至10 s。能量密度定义为束流能量（keV）、电流（mA）和脉冲（s）的乘积除以孔径面积（m²），与栅极无水冷的原始兆电子伏加速器相比，能量密度增加了一个多数量级以上。在更高的能量和电流下，栅极因束流偏转而熔化。由于这种栅极熔化，栅极之间发生击穿，因此脉冲长度受到限制。在下一次实验中，将通过孔径位移来补偿束流偏转。
