Cathode Side-emission Mitigation for Linear Induction Accelerators

Thermionic cathodes have been shown to be a reliable source of electron emission to produce and deliver electron beams of various voltages and currents. One drawback of using thermionic cathodes is the possibility of electrons emitting off the side of the cathode due to high enough electric field values near the cathode edge. These extra electrons induce nonlinearities in phase space which contribute to an increase in beam emittance. In this work we highlight the results of trade-space studies that show by tuning cathode-shroud parameters, we can mitigate these effects on the phase space and generate electron beams whose emittance with side emission electrons is comparable to a beam where side emission is not present.