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Copper Shock: An Atomic-scale Stress Test

October 22, 2013

Menlo Park, Calif. — Scientists used the powerful X-ray laser at the U.S. Department of Energy's SLAC National Accelerator Laboratory to create movies detailing trillionths-of-a-second changes in the arrangement of copper atoms after an extreme shock. Movies like these will help researchers create new kinds of materials and test the strength of existing ones.

This work, published Oct. 11 in Science, pinpointed the precise breaking point when the extreme pressures began to permanently deform the copper structure, or lattice, so it could no longer bounce back to its original shape. Such experiments provide a direct test of complex computer simulations that model the behavior of many millions of atoms within tiny samples of material.

Such simulations are used to design stronger, more durable materials – such as shielding for satellites to withstand high-speed pelting by space debris – but they have been hard to test in the lab because of the tiny samples and short timescales involved.

"The results enable a number of materials experiments that can be compared to simulations at the same scales," said Despina Milathianaki, a staff scientist at SLAC's Linac Coherent Light Source (LCLS) who led the experiment. "This and future experiments, designed to provide a direct comparison with simulations, will help us to accurately predict the strength of materials in extreme conditions."

A sequence of X-ray diffraction images, 10 trillionths of a second apart, shows how a shock impacts the crystal structure, or lattice, of copper at the atomic scale. (D. Milathianaki, S. Boutet, et al./SLAC Multimedia)

 

In this experiment, researchers shocked a layer of copper about 1 thousandth of a millimeter, or 1 micron thick with optical laser pulses, and then probed the copper’s lattice with ultrabright X-ray pulses. They compiled the X-ray images into atomic-scale movies that detail how the lattice responded at various times after the shock, including the moment the copper reached its breaking point.

"The demand for research time at LCLS is already at a premium, and these results demonstrate yet another new technique that we believe will open the door to a host of new experiments," said Sebastien Boutet, who leads LCLS's Coherent X-ray Imaging (CXI) Department, where the measurements were performed.

The same research team – composed mostly of SLAC scientists, with collaborators from University of Oxford, Stanford University and Lawrence Livermore National Laboratory – also shocked other metals, including iron and titanium, and is analyzing the data obtained from those samples.

Follow-up research scheduled at LCLS in March seeks to extend the research to additional materials and to enlist other x-ray scattering techniques, which may provide more details about the origins of the damage in the lattice.

SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the U.S. Department of Energy Office of Science. To learn more, please visit www.slac.stanford.edu.

This research was supported by the Linac Coherent Light Source's (LCLS) in-house research effort. SLAC's LCLS is the world's most powerful X-ray free-electron laser. A DOE national user facility, its highly focused beam shines a billion times brighter than previous X-ray sources to shed light on fundamental processes of chemistry, materials and energy science, technology and life itself. For more information, visit lcls.slac.stanford.edu.

DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.


Citation: D. Milathianaki et al.Science, 11 Oct 2013 (10.1126/science.1239566)

Press Office Contact: Andy Freeberg, SLAC, afreeberg@slac.stanford.edu, (650) 926-4359

Scientist Contact: Despina Milathianaki, despina@SLAC.Stanford.edu

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thin samples of copper, iron and titanium
These thin samples of copper, iron and titanium were shocked with optical laser pulses and probed with SLAC's X-ray laser, the Linac Coherent Light Source (LCLS). (D. Milathianaki, S. Boutet, et al.)
A diagram of the setup used in the ultrafast shock compression experiment at SLAC's Linac Coherent Light Source (LCLS), including a large-area CSPAD detector, X-ray and optical lasers, and thin copper samples. (Greg Stewart/SLAC)
A diagram of the setup used in the ultrafast shock compression experiment at SLAC's Linac Coherent Light Source (LCLS), including a large-area CSPAD detector, X-ray and optical lasers, and thin copper samples. (Greg Stewart/SLAC)
This photo shows the Coherent X-ray Imaging (CXI) sample chamber at SLAC's Linac Coherent Light Source (LCLS) set up for an experiment involving shock compression and X-ray diffraction. (D. Milathianaki, S. Boutet, et al.)
This photo shows the Coherent X-ray Imaging (CXI) sample chamber at SLAC's Linac Coherent Light Source (LCLS) set up for an experiment involving shock compression and X-ray diffraction. (D. Milathianaki, S. Boutet, et al.)
Microscope image of resolidification patterns formed on the surface of silicon after the passage of a shock wave. Scientists at LCLS applied optical laser pulses to launch shocks on various materials on a silicon surface, inducing rapid changes in their l
Microscope image of resolidification patterns formed on the surface of silicon after the passage of a shock wave. Scientists at LCLS applied optical laser pulses to launch shocks on various materials on a silicon surface, inducing rapid changes in their lattice. The changes unfolding at rates of trillionths of a second apart were unveiled using the ultrabright free electron laser of LCLS. (D. Milathianaki, S. Boutet, et al.)
One of a sequence of images showing how a laser-driven shock impacts the crystalline structure, or lattice, of a thin copper sample. The images were combined into a movie that shows trillionths-of-a-second changes in the lattice. (D. Milathianaki, S. Bout
One of a sequence of images showing how a laser-driven shock impacts the crystalline structure, or lattice, of a thin copper sample. The images were combined into a movie that shows trillionths-of-a-second changes in the lattice. (D. Milathianaki, S. Boutet)