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Pulse length, energy spread, and temporal evolution of electron pulses generated with an ultrafast beam blanker

Crucial for the field of ultrafast electron microscopy is the creation of sub-picosecond, high brightness electron pulses. The use of a blanker to chop the beam that originates from a high brightness Schottky source may provide an attractive alternative to direct pulsed laser illumination of the sou...

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Autores principales: Weppelman, I. G. C., Moerland, R. J., Zhang, L., Kieft, E., Kruit, P., Hoogenboom, J. P.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Crystallographic Association 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6486391/
https://www.ncbi.nlm.nih.gov/pubmed/31065571
http://dx.doi.org/10.1063/1.5089517
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author Weppelman, I. G. C.
Moerland, R. J.
Zhang, L.
Kieft, E.
Kruit, P.
Hoogenboom, J. P.
author_facet Weppelman, I. G. C.
Moerland, R. J.
Zhang, L.
Kieft, E.
Kruit, P.
Hoogenboom, J. P.
author_sort Weppelman, I. G. C.
collection PubMed
description Crucial for the field of ultrafast electron microscopy is the creation of sub-picosecond, high brightness electron pulses. The use of a blanker to chop the beam that originates from a high brightness Schottky source may provide an attractive alternative to direct pulsed laser illumination of the source. We have recently presented the concept of a laser-triggered ultrafast beam blanker and argued that generation of 100 fs pulses could be possible [Weppelman et al., Ultramicroscopy 184, 8–17 (2017)]. However, a detailed analysis of the influence of a deflection field changing sign on sub-picoseconds time scale on the quality of the resulting electron pulses has so far been lacking. Here, we present such an analysis using time-dependent, three-dimensional numerical simulations to evaluate the time-evolution of deflection fields in and around a micrometers-scale deflector connected to a photo-conductive switch. Further particle tracing through the time-dependent fields allows us to evaluate beam quality parameters such as energy spread and temporal broadening. We show that with a shielded, “tunnel-type” design of the beam blanker limiting the spatial extent of fringe fields outside the blanker, the blanker-induced energy spread can be limited to 0.5 eV. Moreover, our results confirm that it could be possible to bring laser-triggered 100 fs focused electron pulses on the sample using a miniaturized ultrafast beam blanker. This would enable us to resolve ultrafast dynamics using focused electron pulses in an SEM or STEM.
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spelling pubmed-64863912019-05-07 Pulse length, energy spread, and temporal evolution of electron pulses generated with an ultrafast beam blanker Weppelman, I. G. C. Moerland, R. J. Zhang, L. Kieft, E. Kruit, P. Hoogenboom, J. P. Struct Dyn ARTICLES Crucial for the field of ultrafast electron microscopy is the creation of sub-picosecond, high brightness electron pulses. The use of a blanker to chop the beam that originates from a high brightness Schottky source may provide an attractive alternative to direct pulsed laser illumination of the source. We have recently presented the concept of a laser-triggered ultrafast beam blanker and argued that generation of 100 fs pulses could be possible [Weppelman et al., Ultramicroscopy 184, 8–17 (2017)]. However, a detailed analysis of the influence of a deflection field changing sign on sub-picoseconds time scale on the quality of the resulting electron pulses has so far been lacking. Here, we present such an analysis using time-dependent, three-dimensional numerical simulations to evaluate the time-evolution of deflection fields in and around a micrometers-scale deflector connected to a photo-conductive switch. Further particle tracing through the time-dependent fields allows us to evaluate beam quality parameters such as energy spread and temporal broadening. We show that with a shielded, “tunnel-type” design of the beam blanker limiting the spatial extent of fringe fields outside the blanker, the blanker-induced energy spread can be limited to 0.5 eV. Moreover, our results confirm that it could be possible to bring laser-triggered 100 fs focused electron pulses on the sample using a miniaturized ultrafast beam blanker. This would enable us to resolve ultrafast dynamics using focused electron pulses in an SEM or STEM. American Crystallographic Association 2019-04-26 /pmc/articles/PMC6486391/ /pubmed/31065571 http://dx.doi.org/10.1063/1.5089517 Text en © 2019 Author(s). 2329-7778/2019/6(2)/024102/11 All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle ARTICLES
Weppelman, I. G. C.
Moerland, R. J.
Zhang, L.
Kieft, E.
Kruit, P.
Hoogenboom, J. P.
Pulse length, energy spread, and temporal evolution of electron pulses generated with an ultrafast beam blanker
title Pulse length, energy spread, and temporal evolution of electron pulses generated with an ultrafast beam blanker
title_full Pulse length, energy spread, and temporal evolution of electron pulses generated with an ultrafast beam blanker
title_fullStr Pulse length, energy spread, and temporal evolution of electron pulses generated with an ultrafast beam blanker
title_full_unstemmed Pulse length, energy spread, and temporal evolution of electron pulses generated with an ultrafast beam blanker
title_short Pulse length, energy spread, and temporal evolution of electron pulses generated with an ultrafast beam blanker
title_sort pulse length, energy spread, and temporal evolution of electron pulses generated with an ultrafast beam blanker
topic ARTICLES
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6486391/
https://www.ncbi.nlm.nih.gov/pubmed/31065571
http://dx.doi.org/10.1063/1.5089517
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