Thermionic sources for high-brightness electron beams

The capabilities and limitations of modern thermionic electron sources for producing high-emission-density (>10 A/cm/sup 2/) high-brightness beams are surveyed. The emphasis is on dispenser cathodes. The fabrication techniques and operating mechanisms that determine the operating limitations of existing commercial cathodes are discussed. In addition, cathode improvements that have been demonstrated in various prototype structures are described. >

[1]  R. E. Thomas,et al.  Work function variation versus alloy concentration for dispenser cathodes , 1987 .

[2]  Yue Ying Lau,et al.  Effects of cathode surface roughness on the quality of electron beams , 1986 .

[3]  R. E. Thomas,et al.  The electronic activation by barium and oxygen of different tungsten crystal orientations , 1984 .

[4]  A. Oostrom,et al.  Activation and early life of a pressed barium scandate cathode , 1979 .

[5]  J. Crombeen,et al.  Properties and manufacture of top-layer scandate cathodes , 1986 .

[6]  J. D. Lawson,et al.  The physics of charged-particle beams , 1988 .

[7]  J. Hasker,et al.  “Alternative” auger analysis reveals important properties of M-type and scandate cathodes , 1985 .

[8]  R. E. Thomas,et al.  Orientation dependence of work function: BaO on Ir , 1981 .

[9]  R. E. Thomas,et al.  Investigation of scandate cathodes: emission, fabrication, and activation processes , 1989 .

[10]  R. E. Thomas.  Diffusion and desorption of barium and oxygen on tungsten dispenser cathode surfaces , 1985 .

[11]  R. S. Mills,et al.  Relation between Field Energy and RMS Emittance in Intense Particle Beams , 1985, IEEE Transactions on Nuclear Science.

[12]  A. Shih,et al.  The poisoning and reactivation kinetics of uncoated tungsten-based dispenser cathodes exposed to water vapor , 1986, IEEE Transactions on Electron Devices.

[13]  A. Shih,et al.  Fast turn-on characteristics of tungsten-based dispenser cathodes. II , 1985 .

[14]  A. Shih,et al.  Fast turn-on characteristics of tungsten-based dispenser cathodes following gas exposures , 1983 .

[15]  R. E. Thomas,et al.  Computer controlled techniques for high emission density mapping of thermionic cathodes , 1985 .