A Compact Ultrafast Electron Diffractometer with Relativistic Femtosecond Electron Pulses

Yang, Jinfeng; Gen, Kazuki; Naruse, Nobuyasu; Sakakihara, Shouichi; Yoshida, Yasuhiko

doi:10.3390/qubs4010004

Cited by 13 publications

(8 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, we define this energy-spread induced peak broadening as the mode of radial peak broadening. As it was experimentally demonstrated, sharp diffraction patterns with a good signal-to-noise ratio can be obtained in a single shot with high-order ( ) BD peak at in a single-crystalline Si 41 . We can potentially extract the radial peak-broadening component from a diffraction pattern and obtain the beam energy spread information.…”

Section: Resultsmentioning

confidence: 74%

Toward monochromated sub-nanometer UEM and femtosecond UED

Yang

Wan

Smaluk

et al. 2020

Sci Rep

View full text Add to dashboard Cite

A preliminary design of a mega-electron-volt (MeV) monochromator with 10−5 energy spread for ultrafast electron diffraction (UED) and ultrafast electron microscopy (UEM) is presented. Such a narrow energy spread is advantageous in both the single shot mode, where the momentum resolution in diffraction is improved, and the accumulation mode, where shot-to-shot energy jitter is reduced. In the single-shot mode, we numerically optimized the monochromator efficiency up to 13% achieving 1.3 million electrons per pulse. In the accumulation mode, to mitigate the efficiency degradation caused by the shot-to-shot energy jitter, an optimized gun phase yields only a mild reduction of the single-shot efficiency, therefore the number of accumulated electrons nearly proportional to the repetition rate. Inspired by the recent work of Qi et al. (Phys Rev Lett 124:134803, 2020), a novel concept of applying reverse bending magnets to adjust the energy-dependent path length difference has been successfully realized in designing a MeV monochromator to achieve the minimum energy-dependent path length difference between cathode and sample. Thanks to the achromat design, the pulse length of the electron bunches and the energy-dependent timing jitter can be greatly reduced to the 10 fs level. The introduction of such a monochromator provides a major step forward, towards constructing a UEM with sub-nm resolution and a UED with ten-femtosecond temporal resolution. The one-to-one mapping between the electron beam parameter and the diffraction peak broadening enables a real-time nondestructive diagnosis of the beam energy spread and divergence. The tunable electric–magnetic monochromator allows the scanning of the electron beam energy with a 10−5 precision, enabling online energy matching for the UEM, on-momentum flux maximizing for the UED and real-time energy measuring for energy-loss spectroscopy. A combination of the monochromator and a downstream chicane enables “two-color” double pulses with femtosecond duration and the tunable delay in the range of 10 to 160 fs, which can potentially provide an unprecedented femtosecond time resolution for time resolved UED.

show abstract

Section: Resultsmentioning

confidence: 74%

Toward monochromated sub-nanometer UEM and femtosecond UED

Yang

Wan

Smaluk

et al. 2020

Sci Rep

View full text Add to dashboard Cite

show abstract

“…By sharing a laser on the cathode with the pump pulse on a sample, two events of electron ejection from the cathode and laser pulse on the sample become entangled naturally, resulting in the timing jitter being determined solely by the uncertainty of ToF, i.e. 36 . Fluctuations of the amplitude and phase of RF fields cause beam energy changes that leads to a ToF variation which is inversely proportional to , where gamma denotes the Lorentz factor.…”

Section: Resultsmentioning

confidence: 99%

Novel approach to push the limit of temporal resolution in ultrafast electron diffraction accelerators

Esuain

Hwang

Neumann

et al. 2022

Sci Rep

View full text Add to dashboard Cite

Ultrafast electron diffraction techniques that employ relativistic electrons as a probe have been in the spotlight as a key technology for visualizing structural dynamics which take place on a time scale of a few femtoseconds to hundreds femtoseconds. These applications highly demand not only extreme beam quality in 6-D phase space such as a few nanometer transverse emittances and femtosecond duration but also equivalent beam stability. Although these utmost requirements have been demonstrated by a compact setup with a high-gradient electron gun with state-of-the-art laser technologies, this approach is fundamentally restricted by its nature for compressing the electrons in a short distance by a ballistic bunching method. Here, we propose a new methodology that pushes the limit of timing jitter beyond the state-of-the-art by utilizing consecutive RF cavities. This layout already exists in reality for energy recovery linear accelerator demonstrators. Furthermore, the demonstrators are able to provide MHz repetition rates, which are out of reach for most conventional high-gradient electron guns.

show abstract

“…We believe that this study is of great significance as it demonstrates the possibility of controlling the intermediate phase of VO 2 in the future. Recently, VO 2 materials have been considered promising candidates for optical switches, which undergo ultrafast light-induced structural phase transitions on the order of 100 femtoseconds [ 3 , 4 , 35–38 ]. However, little analysis has been done taking strain into account.…”

Section: Resultsmentioning

confidence: 99%

Quantitative spatial mapping of distorted state phases during the metal-insulator phase transition for nanoscale VO ₂ engineering

Ashida

Ishibe

Yang

et al. 2022

Science and Technology of Advanced Materials

Self Cite

View full text Add to dashboard Cite

Vanadium dioxide (VO 2 ) material, known for changing physical properties due to metal-insulator transition (MIT) near room temperature, has been reported to undergo a phase change depending on the strain. This fact can be a significant problem for nanoscale devices in VO 2 , where the strain field covers a large area fraction, spatially non-uniform, and the amount of strain can vary during the MIT process. Direct measurement of the strain field distribution during MIT is expected to establish a methodology for material phase identification. We have demonstrated the effectiveness of geometric phase analysis (GPA), high-resolution transmission electron microscopy techniques, and transmission electron diffraction (TED). The GPA images show that the nanoregions of interest are under tensile strain conditions of less than 0.4% as well as a compressive strain of about 0.7% (Rutile phase VO 2 [100] direction), indicating that the origin of the newly emerged TED spots in MIT contains a triclinic phase. This study provides a substantial understanding of the strain-temperature phase diagram and strain engineering strategies for effective phase management of nanoscale VO 2 .

show abstract

A Compact Ultrafast Electron Diffractometer with Relativistic Femtosecond Electron Pulses

Cited by 13 publications

References 31 publications

Toward monochromated sub-nanometer UEM and femtosecond UED

Toward monochromated sub-nanometer UEM and femtosecond UED

Novel approach to push the limit of temporal resolution in ultrafast electron diffraction accelerators

Quantitative spatial mapping of distorted state phases during the metal-insulator phase transition for nanoscale VO ₂ engineering

Contact Info

Product

Resources

About

A Compact Ultrafast Electron Diffractometer with Relativistic Femtosecond Electron Pulses

Cited by 13 publications

References 31 publications

Toward monochromated sub-nanometer UEM and femtosecond UED

Toward monochromated sub-nanometer UEM and femtosecond UED

Novel approach to push the limit of temporal resolution in ultrafast electron diffraction accelerators

Quantitative spatial mapping of distorted state phases during the metal-insulator phase transition for nanoscale VO 2 engineering

Contact Info

Product

Resources

About

Quantitative spatial mapping of distorted state phases during the metal-insulator phase transition for nanoscale VO ₂ engineering