The latest tabletop particle accelerator, from University of Texas at Austin, can generate energy and speeds previously only available at major multimillion dollar facilities hundreds of meters long.
"We have accelerated about half a billion electrons to 2 gigaelectronvolts over a distance of about 1 inch," said Mike Downer, professor of physics. "Until now that degree of energy and focus has required a conventional accelerator that stretches more than the length of two football fields. It’s a downsizing of a factor of approximately 10,000."
A gigaelectronvolt is a unit of measure for the amount of energy gained or lost by an electron. With the success of the 2-GeV accelerator, Downer says he expects 10-GeV accelerators of a few inches to be developed in the next few years, and 20-GeV accelerators within a decade.
The 2-GeV accelerator is groundbreaking in its ability to produce X-rays of femtosecond duration, the time scale on which molecules vibrate and the fastest chemical reactions occur. To do this, physicists used the Texas Petawatt Laser, one of the most powerful lasers in the world.
Former UT Austin physicist Toshiki Tajima and the late UCLA physicist John Dawson conceived the idea of laser plasma acceleration in the late 1970s. But experiments since the early 1990s remained limited by the power of their lasers. Maximum energy had been stuck at about 1 GeV for years.
In particular, the petawatt laser was powerful enough to enable scientists to use gases much less dense than those used in previous experiments. Their findings are published in the journal Nature Communications.
With power rising to a level previously only found at large-scale facilities, scientists will be able to observe atomic structures in great detail in labs worldwide, opening research possibilities to more people.
"I don’t think a major breakthrough is required to get there," Downer said. "Companies are now selling petawatt lasers commercially, and as we get better at doing this, companies will come into being to make 10 GeV accelerator modules. Then the end users, the chemists and biologists, will come in, and that will lead to more innovations and discoveries."