Correlation of surface composition with emission property for scandate-type cathodes

In the paper, several kinds of scandate cathodes are investigated by means of AES and corresponded electron emission measurements. The purpose of these experiments is to clarify the relationship between the atomic ratios of surface active elements, namely, Sc and Ba, and electron emission of cathodes. The results of experiments indicate that the excessive or lacking content of surface Sc will lead to decline of electron emission, and only the surface Sc keeping proper content can contribute to excellent electron emission.