Re掺杂对W丝阴极二次电子发射的影响

Enhancement of Secondary Electron Emission Coefficient with Re-Doped W-Coatings on W-Substrate

为了提高纯W丝阴极的二次电子发射系数(δ),在W粉中掺杂不同比例的Re粉。将混合好的W-Re粉制备在W片表面,经高温烧结后测量其二次电子发射系数。实验结果显示Re掺杂合金阴极能够提高纯钨丝阴极的δ。不同掺杂Re的W-Re合金阴极对提高二次电子发射系数的能力不同,掺杂5(质量比)%Re的W-Re合金阴极的二次电子发射系数最大,其最大二次电子发射系数(δm)值为1.8,相比于未掺杂的纯钨粉烧结阴极的δm,能够提高80%。

The surfaces of tungsten disks were modified by coating the Re-doped W-powder to increase the secondary electron emission coefficient（ δ） of pure tungsten filament cathodes. The impact of the coating conditions,including but not limited to the Re-content,grain sizes of Re / W powders,sintering temperature and time,on the secondary electron emission coefficient was experimentally investigated. The Re-W alloy coatings were characterized with scanning electron microscopy,energy dispersive spectroscopy and Auger electron spectroscopy. The results show that depending on the Re-content,the Re-W alloy coating has a major impact on the secondary electron emission coefficient. Coated at a Re-content of 5% wt,the highest secondary electron emission coefficient of the Re-W coating was measured to be 1. 8,80% higher than that of the control sample.