Speaker
Description
Beam brightness can be enhanced with high gradient operation in photocathode guns. Such high gradient guns, such as the L-band gun at the Argonne Wakefield Accelerator (AWA) facility and the C-band high gradient gun being commissioned in the CARIE project at Los Alamos National Laboratory, are also typically equipped with semiconductor photocathodes due to their high quantum efficiency. To investigate the photoemission process in semiconductor thin-film photocathode under such conditions, we developed Monte-Carlo transport and photoemission models employing electronic, phonon, dielectric and optical properties directly from Density Functional Theory (DFT) calculation, as well as the photo excitation model based on the light interference effect in thin films. This photoemission model is further employed in photocathode gun simulation and used to investigate a recent high-gradient experiment conducted at the AWA photo injector. We will discuss the effects of the high field gradient on photoemission through a comparison of the measurement and the simulated beam dynamics.
*Work supported by the LDRD program at LANL.
| Working group | WG5 |
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