by
Thomas Dworetzky, Contributing Reporter | August 16, 2018
What if you could have “bedside” cellphone-sized particle accelerators for diagnosis and therapy instead of today's 10,000 pound behemoths?
Researchers at Stanford University's Accelerator on a Chip International Program (ACHIP) think it's possible, and have been working on developing tiny systems they hope will bring the technology to new places — and new purposes.
The accelerator-on-a-chip concept was sufficiently promising that, in 2015, The Gordon and Betty Moore Foundation awarded $13.5 million to Stanford and an international team to make the conceptual design a scaled and working prototype. The concepts first appeared in 2013 in a report in the journal
Nature by Stanford physics professor Robert Byer and one by Dr. Peter Hommelhoff of Friedrich-Alexander University Erlangen-Nuremberg in
Physical Review Letters.
Byer has spent decades working on the problem of smaller accelerators — based on his idea that lasers could up the energy of electrons flying through a small channel in a semiconductor chip.
"We need to focus the electrons,"
Byer told NPR. "We need to bunch them so they surf the wavelength of light right at the crest, so they get the maximum acceleration."
The wave makes a very tight target. “You have to generate a very, very narrow electron beam that you can send through the channel," Hommelhoff explained.
"It's a little like threading an invisible needle," Dylan Black, a Stanford graduate student in physics, told the radio station.
The two research teams showed that it was possible to shrink laser-driven particle accelerators. Via different experimental methods, both groups of researchers demonstrated that lasers could effectively accelerate electrons – and together the work “opened the door” to developing a compact particle accelerator.
“Based on our proposed revolutionary design, this prototype could set the stage for a new generation of ‘tabletop’ accelerators, with unanticipated discoveries in biology and materials science and potential applications in security scanning, medical therapy and X-ray imaging,” noted Byer at the time.
“This laser-driven particle accelerator could have a major impact on the physics community and on science in general by providing new particle and photon sources that are less expensive to build, address current infrastructure challenges and provide broader access to the scientific community,” the foundation said in a statement at the time the award was made.
