摘要：In this paper, the spectral response and fluorescence spectrum of three Na2KSb multi-alkali cathodes without Cs activation, with Cs activation and with both Cs and Cs-Sb activation were measured. The measurement results show that, Na2KSb cathode after Cs activation, the cathode sensitivity was increased, long-wavelength cutoff wavelength was also extended, but the peak wavelength and peak intensity of fluorescence spectrum was essentially unchanged. The elongation of long-wavelength cutoff wavelength shows that work function of cathode is reduced, so the Na2KSb cathode after Cs activation, the increase of cathode sensitivity and elongation of long-wavelength cutoff wavelength is due to the lower work function. Na2KSb cathode after both Cs activation and Cs-Sb activation, the cathode sensitivity and long-wavelength cutoff wavelength were further increased, but the peak wavelength and peak intensity of fluorescence spectrum was changed. The peak wavelength was shifted towards the short wavelength and peak fluorescence intensity was increased. The shift of peak wavelength toward short direction showed that energy level of transition electron was increased and increasing of peak intensity of fluorescence spectrum showed that number of transition electron was increased. For Na2KSb cathode with Cs activation and Cs-Sb activation, the increase of transition electrons number and transition electron energy level has a positive effect on the cathode sensitivity. Therefore the reasons of increase for cathode sensitivity and long-wavelength cutoff wavelength of Na2KSb cathode by Cs activation and Cs-Sb activation are the increase in the number of transitions and transition electron energy levels except for the reason of reduced surface work function. Cathode surface electron escape mechanism is not yet conclusive, thus to improve the cathode sensitivity, further research is needed to figure out the objective law of cathode surface activation process. This will help to provide theoretical guidance to further improve cathode production process and to increase cathode sensitivity.% 测量了未经过Cs激活、经过Cs激活以及经过Cs-Sb激活的三种多碱阴极的光谱响应及荧光谱.测量结果表明,Na2KSb 阴极膜层经表面激活之后,阴极灵敏度和长波截止波长均有所增加,但荧光谱的峰值波长和峰值荧光强度基本保持不变.长波截止波长的增加说明逸出功降低,因此多碱阴极Na2KSb膜层经Cs激活之后,阴极灵敏度提高和长波截止波长增加的原因是逸出功的降低.Na2KSb膜层同时经过Cs-Sb激活之后,阴极灵敏度和长波截止波长较仅仅经过Cs激活的多碱阴极有进一步更大幅度的提高和增加,但同时荧光谱的峰值波长向短波方向移动,峰值荧光强度增加.荧光谱的峰值波长向短波方向移动,说明跃迁电子的能级有所升高,而荧光谱的峰值强度增加,意味着跃迁电子的数量增加.多碱阴极Na2KSb膜层经过Cs-Sb激活之后,跃迁电子的数量增加以及跃迁电子的能级升高,对阴极灵敏度的提高而言,所取得的作用相同.因此多碱阴极 Na2KSb 膜层经过Cs-Sb激活之后,阴极灵敏度和长波截止波长提高的原因除了表面逸出功降低之外,还有跃迁电子数量增加以及跃迁电子能级提高的原因.多碱阴极表面电子逸出机理至今仍未定论,因此要进一步提高多碱阴极的灵敏度,需要进一步研究多碱阴极表面激活过程中的客观规律,为进一步改进多碱阴极的制作工艺,提高多碱阴极的灵敏度提供理论指导.