Fabrication of a 50 keV Cold Cathode Electron Gun

Amir H. Sari, M. Ghoranneviss, P. Khorshid

Plasma Physics Research Center,Science and Research Campus, Islamic Azad University
P.O.Box 14665-678, Tehran, Iran

In this study the structure and schematic configuration of a concave cold cathode electron gun has been shown, which use obstructed discharge [1-2] for electron producing. The concave cathode works well to coverage the electron beam and reduce particle loss to the chamber wall. The discharge current is adjusted by gas pressure, and in existence of helium gas is about 1*10-3 torr. This type of discharge and mechanism of secondary electron emission by ions and fast neutral interaction have been described [3-5]. A negative DC high voltage is applied to a concave cathode up to -50 kV which determine electron energy. The electron spot size dependence to concave radius has been investigated.

References

[1] Z. Donko, K. Roza, R.C. Tobin, K.A. Peard, Phys Rev E 49 (1994) 3283-9
[2] C.F. Barnett, J.A. Ray, E. Ricci, M.I. Wilker, E.W. Mc Daniel, E.W. Thomas, H.B. Gilbody, Atomic data for controlled fusion research ORNL-5206, 1 (1977)
[3] L.J. Kieffer, G.h. Dunn, Rev Mod Phys 38 (1966) 1-35
[4] D. Rapp, W.E. Francis, J Chem Phys (1962) 2631-45
[5] M. Fukao, I. Masazumi, O. Yoshio, M. Hironobu, Vacuum 59 (2000) 358-372