The Experts below are selected from a list of 2919 Experts worldwide ranked by ideXlab platform
Howard A. Padmore - One of the best experts on this subject based on the ideXlab platform.
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Near atomically smooth alkali Antimonide photocathode thin films
Journal of Applied Physics, 2017Co-Authors: Jun Feng, Siddharth Karkare, J. Nasiatka, Susanne Schubert, John Smedley, Howard A. PadmoreAbstract:Nano-roughness is one of the major factors degrading the emittance of electron beams that can be generated by high efficiency photocathodes, such as the thermally reacted alkali Antimonide thin films. In this paper, we demonstrate a co-deposition based method for producing alkali Antimonide cathodes that produce near atomic smoothness with high reproducibility. We calculate the effect of the surface roughness on the emittance and show that such smooth cathode surfaces are essential for operation of alkali Antimonide cathodes in high field, low emittance radio frequency electron guns and to obtain ultracold electrons for ultrafast electron diffraction applications.
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near atomically smooth alkali Antimonide photocathode thin films
arXiv: Accelerator Physics, 2016Co-Authors: Jun Feng, Siddharth Karkare, J. Nasiatka, Susanne Schubert, John Smedley, Howard A. PadmoreAbstract:Nano-roughness limits the emittance of electron beams that can be generated by high efficiency photocathodes, such as the thermally reacted alkali Antimonide thin films. However there is an urgent need for photocathodes that can produce an order of magnitude or more lower emittance than present day systems in order to increase the transverse coherence width of the electron beam. In this paper we demonstrate a method for producing alkali Antimonide cathodes with near atomic smoothness with high reproducibility.
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bi alkali Antimonide photocathode growth an x ray diffraction study
Journal of Applied Physics, 2016Co-Authors: S. Schubert, Jun Feng, Siddharth Karkare, John Smedley, Howard A. Padmore, Jared Wong, M Ruizoses, Erik Muller, Zihao Ding, Mengjia GaoweiAbstract:Bi-alkali Antimonide photocathodes are one of the best known sources of electrons for high current and/or high bunch charge applications like Energy Recovery Linacs or Free Electron Lasers. Despite their high quantum efficiency in visible light and low intrinsic emittance, the surface roughness of these photocathodes prohibits their use as low emittance cathodes in high accelerating gradient superconducting and normal conducting radio frequency photoguns and limits the minimum possible intrinsic emittance near the threshold. Also, the growth process for these materials is largely based on recipes obtained by trial and error and is very unreliable. In this paper, using X-ray diffraction, we investigate the different structural and chemical changes that take place during the growth process of the bi-alkali Antimonide material K2CsSb. Our measurements give us a deeper understanding of the growth process of alkali-Antimonide photocathodes allowing us to optimize it with the goal of minimizing the surface roughness to preserve the intrinsic emittance at high electric fields and increasing its reproducibility.
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a low emittance and high efficiency visible light photocathode for high brightness accelerator based x ray light sources
Applied Physics Letters, 2011Co-Authors: T. Vecchione, I Benzvi, D Dowell, J Feng, J Smedley, Howard A. PadmoreAbstract:Free-electron lasers and energy recovery linacs represent a new generation of ultra-high brightness electron accelerator based x-ray sources. Photocathodes are a critical performance-limiting component of these systems. Here, we describe the development of photocathodes based on potassium-cesium-Antimonide that satisfy many of the key requirements of future light sources, such as robustness, high quantum efficiency when excited with visible light, and low transverse emittance.
Siddharth Karkare - One of the best experts on this subject based on the ideXlab platform.
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Near atomically smooth alkali Antimonide photocathode thin films
Journal of Applied Physics, 2017Co-Authors: Jun Feng, Siddharth Karkare, J. Nasiatka, Susanne Schubert, John Smedley, Howard A. PadmoreAbstract:Nano-roughness is one of the major factors degrading the emittance of electron beams that can be generated by high efficiency photocathodes, such as the thermally reacted alkali Antimonide thin films. In this paper, we demonstrate a co-deposition based method for producing alkali Antimonide cathodes that produce near atomic smoothness with high reproducibility. We calculate the effect of the surface roughness on the emittance and show that such smooth cathode surfaces are essential for operation of alkali Antimonide cathodes in high field, low emittance radio frequency electron guns and to obtain ultracold electrons for ultrafast electron diffraction applications.
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near atomically smooth alkali Antimonide photocathode thin films
arXiv: Accelerator Physics, 2016Co-Authors: Jun Feng, Siddharth Karkare, J. Nasiatka, Susanne Schubert, John Smedley, Howard A. PadmoreAbstract:Nano-roughness limits the emittance of electron beams that can be generated by high efficiency photocathodes, such as the thermally reacted alkali Antimonide thin films. However there is an urgent need for photocathodes that can produce an order of magnitude or more lower emittance than present day systems in order to increase the transverse coherence width of the electron beam. In this paper we demonstrate a method for producing alkali Antimonide cathodes with near atomic smoothness with high reproducibility.
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bi alkali Antimonide photocathode growth an x ray diffraction study
Journal of Applied Physics, 2016Co-Authors: S. Schubert, Jun Feng, Siddharth Karkare, John Smedley, Howard A. Padmore, Jared Wong, M Ruizoses, Erik Muller, Zihao Ding, Mengjia GaoweiAbstract:Bi-alkali Antimonide photocathodes are one of the best known sources of electrons for high current and/or high bunch charge applications like Energy Recovery Linacs or Free Electron Lasers. Despite their high quantum efficiency in visible light and low intrinsic emittance, the surface roughness of these photocathodes prohibits their use as low emittance cathodes in high accelerating gradient superconducting and normal conducting radio frequency photoguns and limits the minimum possible intrinsic emittance near the threshold. Also, the growth process for these materials is largely based on recipes obtained by trial and error and is very unreliable. In this paper, using X-ray diffraction, we investigate the different structural and chemical changes that take place during the growth process of the bi-alkali Antimonide material K2CsSb. Our measurements give us a deeper understanding of the growth process of alkali-Antimonide photocathodes allowing us to optimize it with the goal of minimizing the surface roughness to preserve the intrinsic emittance at high electric fields and increasing its reproducibility.
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growth and characterization of rugged sodium potassium Antimonide photocathodes for high brilliance photoinjector
Applied Physics Letters, 2013Co-Authors: Luca Cultrera, Siddharth Karkare, B Lillard, Adam Bartnik, Ivan Bazarov, Bruce Dunham, W J Schaff, Karl SmolenskiAbstract:Sodium potassium Antimonide photocathodes with Quantum Efficiency (QE) in the range of few percent have been grown, and their photoemission properties are measured. We report the intrinsic emittance and response time of electron bunches extracted from this material. It is possible to recover the QE of an overheated cathode by simple potassium addition, and the cathode is rugged enough to deliver tens of mA of average current with no or minimal degradation.
Jun Feng - One of the best experts on this subject based on the ideXlab platform.
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Near atomically smooth alkali Antimonide photocathode thin films
Journal of Applied Physics, 2017Co-Authors: Jun Feng, Siddharth Karkare, J. Nasiatka, Susanne Schubert, John Smedley, Howard A. PadmoreAbstract:Nano-roughness is one of the major factors degrading the emittance of electron beams that can be generated by high efficiency photocathodes, such as the thermally reacted alkali Antimonide thin films. In this paper, we demonstrate a co-deposition based method for producing alkali Antimonide cathodes that produce near atomic smoothness with high reproducibility. We calculate the effect of the surface roughness on the emittance and show that such smooth cathode surfaces are essential for operation of alkali Antimonide cathodes in high field, low emittance radio frequency electron guns and to obtain ultracold electrons for ultrafast electron diffraction applications.
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near atomically smooth alkali Antimonide photocathode thin films
arXiv: Accelerator Physics, 2016Co-Authors: Jun Feng, Siddharth Karkare, J. Nasiatka, Susanne Schubert, John Smedley, Howard A. PadmoreAbstract:Nano-roughness limits the emittance of electron beams that can be generated by high efficiency photocathodes, such as the thermally reacted alkali Antimonide thin films. However there is an urgent need for photocathodes that can produce an order of magnitude or more lower emittance than present day systems in order to increase the transverse coherence width of the electron beam. In this paper we demonstrate a method for producing alkali Antimonide cathodes with near atomic smoothness with high reproducibility.
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bi alkali Antimonide photocathode growth an x ray diffraction study
Journal of Applied Physics, 2016Co-Authors: S. Schubert, Jun Feng, Siddharth Karkare, John Smedley, Howard A. Padmore, Jared Wong, M Ruizoses, Erik Muller, Zihao Ding, Mengjia GaoweiAbstract:Bi-alkali Antimonide photocathodes are one of the best known sources of electrons for high current and/or high bunch charge applications like Energy Recovery Linacs or Free Electron Lasers. Despite their high quantum efficiency in visible light and low intrinsic emittance, the surface roughness of these photocathodes prohibits their use as low emittance cathodes in high accelerating gradient superconducting and normal conducting radio frequency photoguns and limits the minimum possible intrinsic emittance near the threshold. Also, the growth process for these materials is largely based on recipes obtained by trial and error and is very unreliable. In this paper, using X-ray diffraction, we investigate the different structural and chemical changes that take place during the growth process of the bi-alkali Antimonide material K2CsSb. Our measurements give us a deeper understanding of the growth process of alkali-Antimonide photocathodes allowing us to optimize it with the goal of minimizing the surface roughness to preserve the intrinsic emittance at high electric fields and increasing its reproducibility.
John Smedley - One of the best experts on this subject based on the ideXlab platform.
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Near atomically smooth alkali Antimonide photocathode thin films
Journal of Applied Physics, 2017Co-Authors: Jun Feng, Siddharth Karkare, J. Nasiatka, Susanne Schubert, John Smedley, Howard A. PadmoreAbstract:Nano-roughness is one of the major factors degrading the emittance of electron beams that can be generated by high efficiency photocathodes, such as the thermally reacted alkali Antimonide thin films. In this paper, we demonstrate a co-deposition based method for producing alkali Antimonide cathodes that produce near atomic smoothness with high reproducibility. We calculate the effect of the surface roughness on the emittance and show that such smooth cathode surfaces are essential for operation of alkali Antimonide cathodes in high field, low emittance radio frequency electron guns and to obtain ultracold electrons for ultrafast electron diffraction applications.
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near atomically smooth alkali Antimonide photocathode thin films
arXiv: Accelerator Physics, 2016Co-Authors: Jun Feng, Siddharth Karkare, J. Nasiatka, Susanne Schubert, John Smedley, Howard A. PadmoreAbstract:Nano-roughness limits the emittance of electron beams that can be generated by high efficiency photocathodes, such as the thermally reacted alkali Antimonide thin films. However there is an urgent need for photocathodes that can produce an order of magnitude or more lower emittance than present day systems in order to increase the transverse coherence width of the electron beam. In this paper we demonstrate a method for producing alkali Antimonide cathodes with near atomic smoothness with high reproducibility.
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bi alkali Antimonide photocathode growth an x ray diffraction study
Journal of Applied Physics, 2016Co-Authors: S. Schubert, Jun Feng, Siddharth Karkare, John Smedley, Howard A. Padmore, Jared Wong, M Ruizoses, Erik Muller, Zihao Ding, Mengjia GaoweiAbstract:Bi-alkali Antimonide photocathodes are one of the best known sources of electrons for high current and/or high bunch charge applications like Energy Recovery Linacs or Free Electron Lasers. Despite their high quantum efficiency in visible light and low intrinsic emittance, the surface roughness of these photocathodes prohibits their use as low emittance cathodes in high accelerating gradient superconducting and normal conducting radio frequency photoguns and limits the minimum possible intrinsic emittance near the threshold. Also, the growth process for these materials is largely based on recipes obtained by trial and error and is very unreliable. In this paper, using X-ray diffraction, we investigate the different structural and chemical changes that take place during the growth process of the bi-alkali Antimonide material K2CsSb. Our measurements give us a deeper understanding of the growth process of alkali-Antimonide photocathodes allowing us to optimize it with the goal of minimizing the surface roughness to preserve the intrinsic emittance at high electric fields and increasing its reproducibility.
Mengjia Gaowei - One of the best experts on this subject based on the ideXlab platform.
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bi alkali Antimonide photocathode growth an x ray diffraction study
Journal of Applied Physics, 2016Co-Authors: S. Schubert, Jun Feng, Siddharth Karkare, John Smedley, Howard A. Padmore, Jared Wong, M Ruizoses, Erik Muller, Zihao Ding, Mengjia GaoweiAbstract:Bi-alkali Antimonide photocathodes are one of the best known sources of electrons for high current and/or high bunch charge applications like Energy Recovery Linacs or Free Electron Lasers. Despite their high quantum efficiency in visible light and low intrinsic emittance, the surface roughness of these photocathodes prohibits their use as low emittance cathodes in high accelerating gradient superconducting and normal conducting radio frequency photoguns and limits the minimum possible intrinsic emittance near the threshold. Also, the growth process for these materials is largely based on recipes obtained by trial and error and is very unreliable. In this paper, using X-ray diffraction, we investigate the different structural and chemical changes that take place during the growth process of the bi-alkali Antimonide material K2CsSb. Our measurements give us a deeper understanding of the growth process of alkali-Antimonide photocathodes allowing us to optimize it with the goal of minimizing the surface roughness to preserve the intrinsic emittance at high electric fields and increasing its reproducibility.