For anyone who’s ever seen a picture of the accelerators at CERN’s (European Particle Physics Laboratory) Large Hadron Collider, the notion of an accelerator-on-a-chip seems unbelievable. Scientists at Stanford’s SLAC National Accelerator Laboratory thought otherwise according to a Sept. 27, 2013 SLAC news release (also on EurekAlert),
In an advance that could dramatically shrink particle accelerators for science and medicine, researchers used a laser to accelerate electrons at a rate 10 times higher than conventional technology in a nanostructured glass chip smaller than a grain of rice.
“We still have a number of challenges before this technology becomes practical for real-world use, but eventually it would substantially reduce the size and cost of future high-energy particle colliders for exploring the world of fundamental particles and forces,” said Joel England, the SLAC physicist who led the experiments. “It could also help enable compact accelerators and X-ray devices for security scanning, medical therapy and imaging, and research in biology and materials science.”
Because it employs commercial lasers and low-cost, mass-production techniques, the researchers believe it will set the stage for new generations of “tabletop” accelerators.
At its full potential, the new “accelerator on a chip” could match the accelerating power of SLAC’s 2-mile-long linear accelerator in just 100 feet, and deliver a million more electron pulses per second. [emphasis mine]
The news release goes on to describe how the researchers have achieved a more efficient acceleration,
Particles are generally accelerated in two stages. First they are boosted to nearly the speed of light. Then any additional acceleration increases their energy, but not their speed; this is the challenging part.
In the accelerator-on-a-chip experiments, electrons are first accelerated to near light-speed in a conventional accelerator. Then they are focused into a tiny, half-micron-high channel within a fused silica glass chip just half a millimeter long. The channel had been patterned with precisely spaced nanoscale ridges. Infrared laser light shining on the pattern generates electrical fields that interact with the electrons in the channel to boost their energy.
The researchers’ have produced an animation which illustrates their work,
Caption: This animation explains how the accelerator on a chip uses infrared laser light to accelerate electrons to increasingly higher energies. Credit: (Greg Stewart/SLAC)
Here’s a citation for and a link to the research paper (‘near final version as of Sept. 30, 2013),
Demonstration of electron acceleration in a laser-driven dielectric microstructure by E. A. Peralta, K. Soong, R. J. England, E. R. Colby, Z. Wu, B. Montazeri, C. McGuinness, J. McNeur, K. J. Leedle, D. Walz, E. B. Sozer, B. Cowan, B. Schwartz, G. Travish, & R. L. Byer. Nature (2013) doi:10.1038/nature12664 Published online 27 September 2013
It is behind a paywall although you can get reading access via ReadCube.
Finally, here’s what the chip looks like,