IPAC2018 - List of Authors (Shen, X.)

Paper	Title	Page
MOPML066	Ultrafast Mega-electron-volt Gas-Phase Electron Diffraction at SLAC National Accelerator Laboratory	556
	X. Shen, R.K. Li, X.J. Wang, S.P. Weathersby, J. Yang SLAC, Menlo Park, California, USA
	Funding: This work was supported in part by the U.S. Department of Energy Contract No. DE-AC02-76SF00515, and the SLAC UED/UEM Initiative Program Development Fund. Ultrashort mega-electron-volt (MeV) electron beams from radio-frequency (rf) photoinjectors have recently attracted strong interests for application in ultrafast gas-phase electron diffraction (UGED). Such high-brightness electron beams are capable of providing 100-fs level temporal resolution and sub-Angstrom level spatial resolution to capture the ultrafast structural dynamics from photoexcited gas molecules. To experimentally demonstrate such an ultrafast electron scattering instrument, a high performance UGED system has been commissioned at SLAC National Accelerator Laboratory. The UGED instrument produces 3.7 MeV electron beams with 2 fC beam charge at 180-Hz repetition rate. The temporal resolution is characterized to be 150 fs full-width-at-half-maximum (FWHM), while the spatial resolution is measured to be 0.76 Å FWHM. The UGED instrument also demonstrates outstanding performance in vacuum, rf, and electron beam pointing stability. Details of the performance of the SLAC MeV UGED system is reported in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML066
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPML011	Experiments Producing Nanopatterned Electron Beams	1553
	L.E. Malin, W.S. Graves, J. Spence, K. Weiss, C. Zhang Arizona State University, Tempe, USA R.K. Li, E.A. Nanni, X. Shen, S.P. Weathersby, J. Yang SLAC, Menlo Park, California, USA
	Funding: Work supported by NSF awards 1632780 and 1231306, DOE award DE-AC02-76SF00515, and the SLAC UED/UEM Initiative Program Development Fund. RF photoinjectors are increasingly used to image at the nanoscale in much the same way as a Transmission Electron Microscope (TEM), which are generally sub-MeV energy. We have conducted electron diffraction experiments through a thin membrane of single crystal silicon using both the TEM and photoinjector, and have been able to model and predict the diffraction patterns using the multislice method. A nanopatterned single crystal silicon grating was also imaged in the TEM in the bright field, where all but the direct beam of the diffraction pattern is blocked, giving high contrast spatial modulations corresponding to the 400 nm pitch grating lithographically etched into the silicon. Drawing from our previous multislice calculations, we determined the crystallographic orientation that maximized the contrast in this spatial modulation at the energy of the TEM, giving a bunching factor comparable to a saturated FEL. We report on these key steps toward control of radiation phase and temporal coherence in an FEL.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML011
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Ultrafast Mega-electron-volt Gas-Phase Electron Diffraction at SLAC National Accelerator Laboratory

556

X. Shen, R.K. Li, X.J. Wang, S.P. Weathersby, J. Yang
SLAC, Menlo Park, California, USA

Funding: This work was supported in part by the U.S. Department of Energy Contract No. DE-AC02-76SF00515, and the SLAC UED/UEM Initiative Program Development Fund.
Ultrashort mega-electron-volt (MeV) electron beams from radio-frequency (rf) photoinjectors have recently attracted strong interests for application in ultrafast gas-phase electron diffraction (UGED). Such high-brightness electron beams are capable of providing 100-fs level temporal resolution and sub-Angstrom level spatial resolution to capture the ultrafast structural dynamics from photoexcited gas molecules. To experimentally demonstrate such an ultrafast electron scattering instrument, a high performance UGED system has been commissioned at SLAC National Accelerator Laboratory. The UGED instrument produces 3.7 MeV electron beams with 2 fC beam charge at 180-Hz repetition rate. The temporal resolution is characterized to be 150 fs full-width-at-half-maximum (FWHM), while the spatial resolution is measured to be 0.76 Å FWHM. The UGED instrument also demonstrates outstanding performance in vacuum, rf, and electron beam pointing stability. Details of the performance of the SLAC MeV UGED system is reported in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML066

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPML011

Experiments Producing Nanopatterned Electron Beams

1553

L.E. Malin, W.S. Graves, J. Spence, K. Weiss, C. Zhang
Arizona State University, Tempe, USA
R.K. Li, E.A. Nanni, X. Shen, S.P. Weathersby, J. Yang
SLAC, Menlo Park, California, USA

Funding: Work supported by NSF awards 1632780 and 1231306, DOE award DE-AC02-76SF00515, and the SLAC UED/UEM Initiative Program Development Fund.
RF photoinjectors are increasingly used to image at the nanoscale in much the same way as a Transmission Electron Microscope (TEM), which are generally sub-MeV energy. We have conducted electron diffraction experiments through a thin membrane of single crystal silicon using both the TEM and photoinjector, and have been able to model and predict the diffraction patterns using the multislice method. A nanopatterned single crystal silicon grating was also imaged in the TEM in the bright field, where all but the direct beam of the diffraction pattern is blocked, giving high contrast spatial modulations corresponding to the 400 nm pitch grating lithographically etched into the silicon. Drawing from our previous multislice calculations, we determined the crystallographic orientation that maximized the contrast in this spatial modulation at the energy of the TEM, giving a bunching factor comparable to a saturated FEL. We report on these key steps toward control of radiation phase and temporal coherence in an FEL.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML011

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)