Title :
Pulsed cathode heating method
Author :
Lipscomb, George A. ; Herniter, Marc E. ; Getty, Ward D.
Author_Institution :
Dept. of Electr. Eng. & Comput. Sci., Michigan Univ., Ann Arbor, MI, USA
fDate :
12/1/1989 12:00:00 AM
Abstract :
A pulsed-mode heating method has been developed and tested for a 1-in.-diameter cathode which reduces the average filament power by over an order of magnitude. The method allows cyclic operation with a few seconds of peak cathode temperature, which allows many microsecond-duration electron pulses to be fired at the peak cathode temperature in each cycle. For a 2-in.-diameter 0.125-in.-thick LaB6 cathode, the saving is just as great. A 1.68-mF capacitor at 6 kV can cycle the larger cathode from 494° to 1800°C and back in 120 s. The energy requirement is 30.2 kJ, which is an average power of 252 W. This is still a saving of over an order of magnitude from the case of steady heating. The same cathode thickness as in the 1-in. case is assumed in this prediction
Keywords :
heating; lanthanum compounds; thermionic cathodes; thermionic electron emission; 0.125 in; 1 in; 1.68 mF; 120 s; 2 in; 252 W; 30.2 J; 494 to 1800 degC; 6 kV; LaB6 cathode; capacitor; cyclic operation; microsecond-duration electron pulses; peak cathode temperature; pulsed cathode heating method; Cathodes; Current density; Electron beams; Heating; Lanthanum; Open loop systems; Plasma temperature; Pulse modulation; Steady-state; Temperature distribution;
Journal_Title :
Plasma Science, IEEE Transactions on
