Sputtered magnesium as a photocathode material for rf injectors
Sputtered magnesium as a photocathode material for rf injectors
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溅射镁作为射频注入器的光电阴极材料
DOI：
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
M. Woodle
中科院分区：
文献类型：
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作者：
T. Srinivasan;J. Schill;I. B. Zvi;M. Woodle
在本文中，我们报告了溅射镁作为射频注入器中合适的光电子发射体的研究。测量在20 μm厚的Mg层上进行，所述Mg层离子溅射在铜衬底上。对该样品的紫外激光损伤阈值测量表明，在266 nm处的激光能量密度高达100 μJ/mm 2时，辐照表面与未辐照表面无法区分。对于100-300 μJ/mm 2范围内的激光能量密度，表面的轻微粗糙化是明显的。在600 μJ/mm 2时，损伤可见，深度估计为101 μm。该损伤阈值比块体镁的损伤阈值大六倍，并且接近铜的损伤阈值。系统的激光清洗将表面的量子效率从2×10−5提高到2×10−3。溅射镁的高量子效率和高损伤阈值的这种组合产生了金属阴极的25 kA/mm 2的创纪录电流密度。研究了激光清洗对溅射镁的影响，并对样品进行了分析。
In this article, we report the investigation of sputtered magnesium as a suitable photoelectron emitter in a rf injector. The measurements were conducted on a 20 μm thick Mg layer, ion sputtered on a copper substrate. UV laser induced damage threshold measurements on this sample indicate that laser energy densities of up to 100 μJ/mm2 at 266 nm, the irradiated surface is indistinguishable from the unirradiated surface. For laser energy densities in the range of 100–300 μJ/mm2, slight roughening of the surface was evident. At 600 μJ/mm2, damage is visible, with the depth estimated to be ∼1 μm. This damage threshold is six times larger than that of the bulk magnesium and approaches that of copper. Systematic laser cleaning has improved the quantum efficiency of the surface from 2×10−5 to 2×10−3. This combination of high quantum efficiency and high damage threshold of sputtered magnesium produces a record current density of 25 kA/mm2 for a metal cathode. The effect of laser cleaning on sputtered Mg, the samp...