High-current electron beam generation in a diode with a multicapillary dielectric cathode

J. Z. Gleizer, Y. Hadas, V. Tz. Gurovich, J. Felsteiner, Ya. E. Krasik
2008 Journal of Applied Physics  
Results of high-current electron beam generation in an ϳ200 kV, ϳ250 ns diode with a multicapillary dielectric cathode ͑MCDC͒ assisted by either velvet-type or ferroelectric plasma sources ͑FPSs͒ are presented. Multicapillary cathodes made of cordierite, glass, and quartz glass samples were studied. It was found that the source of electrons is the plasma ejected from capillaries. The plasma parameters inside capillary channels and in the vicinity of the cathode surface were determined during
more » ... accelerating pulse using visible range spectroscopy. It was shown that glass multicapillary cathodes are characterized by less surface erosion than the cordierite cathodes. Also, it was found that multicapillary cathodes assisted by a FPS showed longer lifetime and better vacuum compatibility than multicapillary cathodes assisted by a velvet-type igniter. Finally, it was found that quartz glass MCDC assisted by FPS is characterized by almost simultaneous formation of the plasma in a cross-sectional area of the dielectric sample with respect to the beginning of the accelerating pulse. The latter is explained by intense UV radiation which synchronized formation of parallel discharges due to induced secondary electron emission.
doi:10.1063/1.2887922 fatcat:ykmduzqrgfcjlfn3vt2sbvoowq