Shaped cathodes for the production of ultra-short multi-electron pulses

Petruk, Ariel Alcides; Pichugin, Kostyantyn; Sciaini, Germán

doi:10.1063/1.4974779

Cited by 11 publications

(7 citation statements)

References 87 publications

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“…As the cathode radius of curvature gets smaller and becomes comparable to the laser spot size, both transverse and longitudinal effects need to be considered. The electric field enhancement along a curved surface discussed earlier, can be used to increase the accelerating field in the cathode area while keeping a large transverse emission size, obtaining at the same time extraction of multi-electron beams and ultrashort pulses from setups with otherwise modest accelerating gradients, typically DC guns (Petruk et al, 2017). A similar approach can be taken in cathodes for RF guns.…”

Section: The Effect Of the Cathode Curvaturementioning

confidence: 99%

Ultrafast Electron Diffraction: Visualizing Dynamic States of Matter

Filippetto,

Musumeci,

et al. 2022

Preprint

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Since the discovery of electron-wave duality, electron scattering instrumentation has developed into a powerful array of techniques for revealing the atomic structure of matter. Beyond detecting local lattice variations in equilibrium structures with the highest possible spatial resolution, recent research efforts have been directed towards the long sought-after dream of visualizing the dynamic evolution of matter in real-time. The atomic behavior at ultrafast timescales carries critical information on phase transition and chemical reaction dynamics, the coupling of electronic and nuclear degrees of freedom in materials and molecules, the correlation between structure, function and previously hidden metastable or nonequilibrium states of matter. Ultrafast electron pulses play an essential role in this scientific endeavor, and their generation has been facilitated by rapid technical advances in both ultrafast laser and particle accelerator technologies. This review presents a summary of the remarkable developments in this field over the last few decades. The physics and technology of ultrafast electron beams is presented with an emphasis on the figures of merit most relevant for ultrafast electron diffraction (UED) experiments. We discuss recent developments in the generation, manipulation and characterization of ultrashort electron beams aimed at improving the combined spatio-temporal resolution of these measurements. The fundamentals of electron scattering from atomic matter and the theoretical frameworks for retrieving dynamic structural information from solid-state and gas-phase samples is described. Essential experimental techniques and several landmark works that have applied these approaches are also highlighted to demonstrate the widening applicability of these methods. Ultrafast electron probes with ever improving capabilities, combined with other complementary photonbased or spectroscopic approaches, hold tremendous potential for revolutionizing our ability to observe and understand energy and matter at atomic scales.

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Section: The Effect Of the Cathode Curvaturementioning

confidence: 99%

Ultrafast Electron Diffraction: Visualizing Dynamic States of Matter

Filippetto,

Musumeci,

et al. 2022

Preprint

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“…Hence, a more general expression for Equation (16) follows, Equation 17: In all aforementioned FED experiments, the temporal resolution was in the range of ≈ 100 -350-fs. In pursuit of a different DC fs-electron gun concept capable of producing sub-100-fs, and ideally sub-30-fs multi-electron bunches, Petruk et al [224] found that ∆t p is governed the strength of the electric field at the cathode's surface since most of the temporal broadening occurs during the initial stage of electron propagation [225]. Hence, a more general expression for Equation (16) follows, Equation 17:…”

Section: Bright Compact Direct Current (Dc) Fed Setupsmentioning

confidence: 99%

“…where E g is the magnitude of the geometrical electric field at the cathode's surface, i.e., in the area where electrons are born.] Equation (17) stresses the need to achieve both high electric field strengths and low initial momentum (or energy) spread at the cathode's surface in order to minimize the temporal broadening caused by ∆p 0 as well as additional broadening arising from instabilities in the high-voltage power supply [224]. Note that ∆p 0 affects both the temporal and spatial resolutions (see definition of L x in Equation (6)).…”

Section: Bright Compact Direct Current (Dc) Fed Setupsmentioning

confidence: 99%

Recent Advances in Ultrafast Structural Techniques

Sciaini

2019

Applied Sciences

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A review that summarizes the most recent technological developments in the field of ultrafast structural dynamics with focus on the use of ultrashort X-ray and electron pulses follows. Atomistic views of chemical processes and phase transformations have long been the exclusive domain of computer simulators. The advent of femtosecond (fs) hard X-ray and fs-electron diffraction techniques made it possible to bring such a level of scrutiny to the experimental area. The following review article provides a summary of the main ultrafast techniques that enabled the generation of atomically resolved movies utilizing ultrashort X-ray and electron pulses. Recent advances are discussed with emphasis on synchrotron-based methods, tabletop fs-X-ray plasma sources, ultrabright fs-electron diffractometers, and timing techniques developed to further improve the temporal resolution and fully exploit the use of intense and ultrashort X-ray free electron laser (XFEL) pulses.

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“…By increasing the energy of short pulses of electrons to the megaelectron volt regime, the space charge effect can be suppressed, which has enabled electron pulses of tens of picocoulombs and hundreds of femtoseconds as well as sub-10-fs electron pulses of tens of femtocoulombs [21][22][23] . A technique has also been developed for minimizing the influence of the space charge effect by placing the specimen or measurement position very close to the DC electron gun 24,25 . Although this method can suppress the increase of electron energy, the space charge effect remains as a limitation.…”

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confidence: 99%

Jitter-free 40-fs 375-keV electron pulses directly accelerated by an intense laser beam and their application to direct observation of laser pulse propagation in a vacuum

Inoue

Shimizu

Nakamiya

et al. 2020

Sci Rep

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We report the generation of ultrashort bright electron pulses directly driven by irradiating a solid target with intense femtosecond laser pulses. The duration of electron pulses after compression by a phase rotator composed of permanent magnets was measured as 89 fs via the ponderomotive scattering of electron and laser pulses, which were almost at the compression limit due to the dispersion of the electron optics. The electron pulse compression system consisting of permanent magnets enabled extremely high timing stability between the laser pulse and electron pulse. The long-term RMS arrival time drift was below 14 fs in 4 h, which was limited by the resolution of the current setup. Because there was no time-varying field to generate jitter, the timing jitter was essentially reduced to zero. To demonstrate the capability of the ultrafast electron pulses, we used them to directly visualize laser pulse propagation in a vacuum and perform 2D mapping of the electric fields generated by low-density plasma in real time.

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Shaped cathodes for the production of ultra-short multi-electron pulses

Cited by 11 publications

References 87 publications

Ultrafast Electron Diffraction: Visualizing Dynamic States of Matter

Ultrafast Electron Diffraction: Visualizing Dynamic States of Matter

Recent Advances in Ultrafast Structural Techniques

Jitter-free 40-fs 375-keV electron pulses directly accelerated by an intense laser beam and their application to direct observation of laser pulse propagation in a vacuum

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