Photocathodes capable of delivering high average current, low emittance, and high brightness electron beams, with a long lifetime and high quantum efficiency are needed for the effective op- eration of modern accelerator facilities managed by the Department of Energy (DOE). Recent experiments on alkali-antimonide and heterostructured semiconductor photocathodes have demon- strated the potential of these materials to generate electron beams with the targeted properties. The physics of these complex materials with different heterostructured configurations possible is not well understood. Tech-X Corporation propose to develop software to enable high-fidelity, three-dimensional, modeling capabilities to simulate and design alkali-antimonide and semiconductor heterostructured photocathodes that meet or exceed the desired operational parameters for DOE facilities. Tech-X Corporation will design and develop software code for modeling of electron generation in alkali-antimonide photocathodes due to absorption of photons with given energies and charge particle transport based on the Monte Carlo approach for treating scattering processes. Tech-X Corporation will include the important effects of built-in fields due to heterojunctions and band bending in surface space-charge regions. Tech-X Corporation will model the physics of electron emission using a general approach for treating photocathode surface potentials. The developed models will be implemented to enable end-to-end, high-fidelity three-dimensional simulations of electron generation, transport, and electron emission from alkali- antimonide photocathodes. Tech-X Corporation will investigate and prototype algorithms for electron generation due to optical excitations, electron scattering with phonons, charge impurities, and other charged carriers. Tech-X Corporation will explore how to take into account effects of built-in fields due to heterojunctions and surface space-charge regions. Tech-X Corporation will develop a proof-of-concept prototype simulation of charge generation, transport, and electron emission from an alkali-antimonide photocathode. Advanced electron sources capable of delivering high average current are essential for next generation electron-ion colliders, electron cooling, free electron laser, and X-ray light source facilities that are being developed by the Department of Energy. Tech-X Corporation will develop high-fidelity software to facilitate efficient engineering of new alkali-antimonide photocathodes that can deliver the required high average current and quantum efficiency over a long operational lifetime. Commercial Applications and Other
Benefits:The proposed new modeling capabilities will be added to VSim, a Tech-X software product, and will aid researchers in developing electron sources that meet or exceed the desired operational pa- rameters for future DOE facilities. This project will produce commercial quality software, including a state-of-the-art graphical user interface, and will increase VSims capability to generate further commercial revenue as it finds use in the industrial design of reliable and durable high quantum efficiency photocathodes and complex, three-dimensional semiconductor devices.
