论文标题
转换器表面等离子体源的改进
Improvement of Converter Surface Plasma Sources
论文作者
论文摘要
为Los Alamos线性加速器开发了具有偏置转换器的大体积表面源（SPS）。带有多极磁性壁和2个加热阴极的大气体释放室可以支持产生排放的血浆。直径为5 cm的冷却转换器，受正离子并发出次要负离子轰击的可能性高达-300 V的电势会加速它们，并集中在直径为6.4 mm的发射孔径上。从此，在高达10％的占空比时提取了多达18 mA的H离子。发射的H束电流通过厚厚的气体和排放血浆层破坏而衰减。可以通过减小转换器表面和发射孔之间的气体和血浆层厚度来提高H束强度和H-产生效率。通过对转换后的SP进行小的修改，可以改善光束特性。我们建议在转换器前使用薄笔放电。笔放电的磁场由永久磁铁产生。减少转换器和发射孔之间的等离子体端气体层可以减少H梁损耗，从而增加提取的束强度高达2倍
A large volume surface plasma source (SPS) with a biased converter was developed for the Los Alamos linear accelerator. A large gas-discharge chamber with a multipole magnetic wall and 2 heated cathodes can support a discharge generating plasma. A cooled converter with a diameter of 5 cm and a potential of up to -300 V bombarded by positive ions and emits secondary negative ions, accelerates them and focuses in an emission aperture with a diameter of 6.4 mm. From this SPS, up to 18 mA of H- ions are extracted at a duty cycle of up to 10%. The emitted H- beam current is attenuated through H- destruction in thick layer of gas and discharge plasma. The H- beam intensity and H- generation efficiency can be increased by decreasing the gas and plasma layer thickness between the converter surface and the emission aperture. It is possible to improve beam characteristics by making a small modification to the converted SPS. We propose to use a thin Penning discharge in front of the converter. The magnetic field for the Penning discharge is created by permanent magnets. Decreasing the plasma end gas layer between the converter and the emission aperture can decrease the H- beam loss and thus increase the extracted beam intensity up to 2 times
