Theory and mitigation of electron back-bombardment in thermionic cathode radio frequency guns
Photocathode RF guns are currently the standard for high- power, low-emittance beam generation in free-electron lasers. These devices require the use of high-power lasers (which are bulky and expensive to operate) and high-quantum-efficiency cathodes (which have limited lifetimes requiring frequent replacement). The use of RF-gated thermionic cathodes enables operation without a large drive laser and with long lifetimes. One major limitation of RF-gated thermionic cathodes is that electrons emitted late in the RF period will not gain enough energy to exit the gun before being accelerated back ...
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