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Title: Femtosecond mega-electron-volt electron microdiffraction

To understand and control the basic functions of physical, chemical and biological processes from micron to nano-meter scale, an instrument capable of visualizing transient structural changes of inhomogeneous materials with atomic spatial and temporal resolutions, is required. One such technique is femtosecond electron microdiffraction, in which a short electron pulse with femtosecond-scale duration is focused into a micron-scale spot and used to obtain diffraction images to resolve ultrafast structural dynamics over a localized crystalline domain. In this letter, we report the experimental demonstration of time-resolved mega-electron-volt electron microdiffraction which achieves a 5 μm root-mean-square (rms) beam size on the sample and a 110 fs rms temporal resolution. Using pulses of 10k electrons at 4.2 MeV energy with a normalized emittance 3 nm-rad, we obtained high quality diffraction from a single 10 μm paraffin ( C 44 H 90) crystal. The phonon softening mode in optical-pumped polycrystalline Bi was also time-resolved, demonstrating the temporal resolution limits of the instrument. In conclusion, this new characterization capability will open many research opportunities in material and biological sciences.
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1]
  1. SLAC National Accelerator Lab., Menlo Park, CA (United States)
Publication Date:
Grant/Contract Number:
AC02-76SF00515
Type:
Accepted Manuscript
Journal Name:
Ultramicroscopy
Additional Journal Information:
Journal Volume: 184; Journal Issue: PA; Journal ID: ISSN 0304-3991
Publisher:
Elsevier
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE
OSTI Identifier:
1416370

Shen, X., Li, R. K., Lundstrom, U., Lane, T. J., Reid, A. H., Weathersby, S. P., and Wang, X. J.. Femtosecond mega-electron-volt electron microdiffraction. United States: N. p., Web. doi:10.1016/j.ultramic.2017.08.019.
Shen, X., Li, R. K., Lundstrom, U., Lane, T. J., Reid, A. H., Weathersby, S. P., & Wang, X. J.. Femtosecond mega-electron-volt electron microdiffraction. United States. doi:10.1016/j.ultramic.2017.08.019.
Shen, X., Li, R. K., Lundstrom, U., Lane, T. J., Reid, A. H., Weathersby, S. P., and Wang, X. J.. 2017. "Femtosecond mega-electron-volt electron microdiffraction". United States. doi:10.1016/j.ultramic.2017.08.019. https://www.osti.gov/servlets/purl/1416370.
@article{osti_1416370,
title = {Femtosecond mega-electron-volt electron microdiffraction},
author = {Shen, X. and Li, R. K. and Lundstrom, U. and Lane, T. J. and Reid, A. H. and Weathersby, S. P. and Wang, X. J.},
abstractNote = {To understand and control the basic functions of physical, chemical and biological processes from micron to nano-meter scale, an instrument capable of visualizing transient structural changes of inhomogeneous materials with atomic spatial and temporal resolutions, is required. One such technique is femtosecond electron microdiffraction, in which a short electron pulse with femtosecond-scale duration is focused into a micron-scale spot and used to obtain diffraction images to resolve ultrafast structural dynamics over a localized crystalline domain. In this letter, we report the experimental demonstration of time-resolved mega-electron-volt electron microdiffraction which achieves a 5 μm root-mean-square (rms) beam size on the sample and a 110 fs rms temporal resolution. Using pulses of 10k electrons at 4.2 MeV energy with a normalized emittance 3 nm-rad, we obtained high quality diffraction from a single 10 μm paraffin (C44H90) crystal. The phonon softening mode in optical-pumped polycrystalline Bi was also time-resolved, demonstrating the temporal resolution limits of the instrument. In conclusion, this new characterization capability will open many research opportunities in material and biological sciences.},
doi = {10.1016/j.ultramic.2017.08.019},
journal = {Ultramicroscopy},
number = PA,
volume = 184,
place = {United States},
year = {2017},
month = {9}
}