Ultrafast electron microscopy in materials science, biology, and chemistry

Journal Article · Wed Jun 01 00:00:00 EDT 2005 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.1927699· OSTI ID:20711698

King, Wayne E; Campbell, Geoffrey H; Frank, Alan; Reed, Bryan; Schmerge, John F; Siwick, Bradley J; Stuart, Brent C; Weber, Peter M ^[1]

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1. University of California Lawrence Livermore National Laboratory, L-356, 7000 East Avenue, Livermore, California 94551 (United States)

The use of pump-probe experiments to study complex transient events has been an area of significant interest in materials science, biology, and chemistry. While the emphasis has been on laser pump with laser probe and laser pump with x-ray probe experiments, there is a significant and growing interest in using electrons as probes. Early experiments used electrons for gas-phase diffraction of photostimulated chemical reactions. More recently, scientists are beginning to explore phenomena in the solid state such as phase transformations, twinning, solid-state chemical reactions, radiation damage, and shock propagation. This review focuses on the emerging area of ultrafast electron microscopy (UEM), which comprises ultrafast electron diffraction (UED) and dynamic transmission electron microscopy (DTEM). The topics that are treated include the following: (1) The physics of electrons as an ultrafast probe. This encompasses the propagation dynamics of the electrons (space-charge effect, Child's law, Boersch effect) and extends to relativistic effects. (2) The anatomy of UED and DTEM instruments. This includes discussions of the photoactivated electron gun (also known as photogun or photoelectron gun) at conventional energies (60-200 keV) and extends to MeV beams generated by rf guns. Another critical aspect of the systems is the electron detector. Charge-coupled device cameras and microchannel-plate-based cameras are compared and contrasted. The effect of various physical phenomena on detective quantum efficiency is discussed. (3) Practical aspects of operation. This includes determination of time zero, measurement of pulse-length, and strategies for pulse compression. (4) Current and potential applications in materials science, biology, and chemistry. UEM has the potential to make a significant impact in future science and technology. Understanding of reaction pathways of complex transient phenomena in materials science, biology, and chemistry will provide fundamental knowledge for discovery-class science.

• OSTI ID: 20711698
• Journal Information: Journal of Applied Physics, Vol. 97, Issue 11; Other Information: DOI: 10.1063/1.1927699; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CAMERAS
CHARGE-COUPLED DEVICES
CHEMICAL REACTIONS
COMPRESSION
ELECTRON DIFFRACTION
ELECTRON GUNS
KEV RANGE 10-100
KEV RANGE 100-1000
MEV RANGE 01-10
PHASE TRANSFORMATIONS
QUANTUM EFFICIENCY
RELATIVISTIC RANGE
SPACE CHARGE
TRANSMISSION ELECTRON MICROSCOPY
TWINNING