摘要:
中性束离子源束光学特性直接影响中性束注入功率。通过理论计算和实验扫描的方式对引出束半宽度随导流系数的变化进行了研究。理论上, 采用IGUN程序对HL-2A装置的三电极引出加速器进行了束元轨迹模拟, 采用束几何光学计算程序对高斯束元进行叠加, 得到了在束线量热靶处引出束的1/e半宽度。实验上, 在放电气体为氘气, 弧放电电流分别为200, 300, 400 A时, 对引出高压进行扫描, 利用量热靶上的热偶测量了不同位置处的温升, 用高斯函数拟合得到引出束的分布和1/e半宽度。理论计算和实验结果都表明, 束半宽随着导流系数的增加先减少后逐渐增加。理论计算结果表明不同离子束流下的最佳导流系数值基本不变, 而实验上, 弧流为200, 300, 400 A时, 对应的最佳导流系数分别为1.6, 1.7, 1.85 P。
Abstract:
The beam optic characteristics of the neutral beam ion source affects the neutral beam injection power. With theoretical calculation and experimental scanning, study on the variation of half width of extraction beam with perveance is carried out. Theoretically, the 1/e half-width of extraction beam at the calorimetric target is obtained with IGUN program simulating trajectory of element beam to the 3 electrodes extraction accelerator on HL-2A device and beam geometry optic program calculating the superposition of every element beam. Experimentally, when the discharge gas is deuterium, the extraction voltage is scanned separately for arc current at 200 A, 300 A and 400 A, and the 1/e half-width of extraction beam is obtained with temperature rise curves measured by thermal couples on the calorimetric target. Theoretical and experimental results show that with the perveance increasing, the beam half width decreases first and then increases gradually. The optimum perveance value keeps almost the same for different beam current by theoretical result, while for arc current at 200, 300 and 400 A, the optimum perveances are 1.6, 1.7 and 1.85 P separately by experimental result.
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