TY - GEN
T1 - Modeling cathode roughness, work function, and field enhancement effects on electron emission
AU - Dimitrov, D. A.
AU - Bell, G. I.
AU - Smithe, D.
AU - Veitzer, S.
AU - Ben-Zvi, I.
AU - Smedley, J.
AU - Feng, J.
AU - Karkare, S.
AU - Padmore, H. A.
N1 - Funding Information:
∗ We are grateful to the U.S. DoE Office of Basic Energy Sciences for supporting this work under the grant DE-SC0013190.
Publisher Copyright:
© 2017 CC-BY-3.0 and by the respective authors
PY - 2017/7
Y1 - 2017/7
N2 - Recent developments in material design and growth have resulted in photocathodes that can deliver high quantum efficiency and are sufficiently robust to use in high electric field gradient photoinjectors and free electron lasers. The growth process usually produces photoemissive material layers with rough surface profiles that lead to transverse accelerating fields and possible work function variation resulting in emittance growth. To better understand the effects of surface roughness on emitted electron beams, we have developed realistic three-dimensional models for photocathode materials with grated surface structures. They include general modeling of electron excitation due to photon absorption, charge transport and emission from rough surfaces taking into account image charge and field enhancement effects. We implemented these models in the VSim particle-in-cell code. We report results from simulations using different photocathode materials with grated and flat surfaces to investigate how controlled roughness, work function variation, and field enhancement affect emission properties.
AB - Recent developments in material design and growth have resulted in photocathodes that can deliver high quantum efficiency and are sufficiently robust to use in high electric field gradient photoinjectors and free electron lasers. The growth process usually produces photoemissive material layers with rough surface profiles that lead to transverse accelerating fields and possible work function variation resulting in emittance growth. To better understand the effects of surface roughness on emitted electron beams, we have developed realistic three-dimensional models for photocathode materials with grated surface structures. They include general modeling of electron excitation due to photon absorption, charge transport and emission from rough surfaces taking into account image charge and field enhancement effects. We implemented these models in the VSim particle-in-cell code. We report results from simulations using different photocathode materials with grated and flat surfaces to investigate how controlled roughness, work function variation, and field enhancement affect emission properties.
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M3 - Conference contribution
AN - SCOPUS:85119700010
T3 - IPAC 2017 - Proceedings of the 8th International Particle Accelerator Conference
SP - 3869
EP - 3871
BT - IPAC 2017 - Proceedings of the 8th International Particle Accelerator Conference
PB - Joint Accelerator Conferences Website - JACoW
T2 - 8th International Particle Accelerator Conference, IPAC 2017
Y2 - 14 May 2017 through 19 May 2017
ER -