Research on Pulsed High-Current Secondary Electron Emission Cathode

Pulsed secondary electron multipacting (SEM) cathodes with channel-type structures were developed. The electron emission performance of cathodes was investigated by theoritical and particle in cell (PIC) simulation methods. The results revealed that the electrical conductivity of the channel wall material played a key role in the performance of the cathodes. The materials with low conductivity would lead to a stop of the SEM process in the milpacting channel because of the space charges deposited on the channel wall. The materials with high conductivity, high secondary electron emission yield, such as SnO
2
, were beneficial for the SEM process, leading to the stable current output of the cathodes with high current density. For a cathode with three multipacting channels, an output current density of 242 A/cm
²
, with excellent stability.