Intense pulsed emission of velvet and carbon nanotube cathodes

Experiments on intense pulsed emission properties of velvet and carbon nanotube(CNT) cathodes have been conducted on the 2 MeV linear induction accelerator injector. The results show that both velvet and CNT cathodes can emit intense electron beams under 1.61 MV pulsed high voltage. The intense electron beams are 84 and 108 A/cm2 in current density, and the turn-on times are 21 and 40 ns, respectively. The amount of outgassing is estimated to be 0.29 and 0.91 PaL, and the number of outgassed molecules per electron is 64 and 225 for velvet and CNT cathodes. Moreover, the outgassing mass spectra of the two cathodes are similar to each other.