There are only two accelerators in the United States capable of producing 10 billion electron volt particle beams, and each is about 1.9 miles (3 kilometers) long. "We can now achieve this energy level within 10 centimeters (4 inches)," said TAU Systems' CEO.
"Such a compact, advanced accelerator also requires a huge laser to operate - in this case, the Texas Petawatt Laser, which is housed on a 34-foot (10-meter) long stage at the High Energy Density Science Center at The University of Texas at Austin," said TAU Systems CEO.
As one of the most powerful lasers in the world, this "behemoth" can emit a super-powerful laser beam with approximately 1,000 times the energy of the installed capacity in the United States, but it can only be emitted once per hour and can only last for 150 femtoseconds, which is one billionth of the lightning discharge time.
TAU's device is less than 66 feet (20 meters) long and emits beams up to 10 GeV. It uses an improved version of Ruofei acceleration technology first described in 1979 and currently used by many accelerator programs.
Ordinary particle accelerators are actually a series of rings that attract electrons when a positive voltage is applied to them. The rings are energized in turn, pulling the electrons through the tunnel at increasing speeds, with each ring closing before the electrons arrive.
Laser-driven accelerators more or less turn the light pulses themselves into light-speed electromagnets, allowing particles to follow them, gathering extraordinary speeds and energy over extremely short distances.
TAU's device uses a chamber filled with helium gas. When a Petawatt laser fires a pulse of light through these gases, the huge energy of the pulse ionizes the gas into a plasma. As it travels through the plasma, the pulse leaves a wake behind it, much like the wake a ship leaves behind when it travels through water, except in this case it creates an extremely powerful wake of charge fluctuations.
If an electron is injected at just the right moment, these giant moving charges pull and push behind the light pulse, draining the energy (but not the speed) of the original laser pulse and transferring it to the accelerating electron, pushing it up to "a large fraction of the speed of light" over a short distance.
TAU's key advance in this device is the use of an auxiliary ablation laser that fires precisely timed pulse trains at a metal plate in a gas chamber, injecting a stream of metal nanoparticles into the gas chamber to increase the energy of the electrons as they follow the laser pulse train.
"It's hard to get into a big wave without getting crushed, so surfers get dragged into the wave by jet skis," said Bjorn "Manuel" Hegelich, associate professor of physics at the University of Texas at Austin and CEO of TAU Systems. "The equivalent of a jet ski in our accelerator are nanoparticles that release electrons at the right time and at the right point, so they're in the wave." We can get more electrons into the wave when and where we want them, rather than being statistically distributed throughout the interaction, and that's the secret. "
Heglich and his team are developing their own desktop-sized laser system, which they say will make the entire system more compact and will fire thousands of times per second instead of once per hour.
So, what is the use of ultra-small high-energy particle accelerators? Perhaps used to drive X-ray free electron lasers, it could potentially capture slow-motion video at the atomic or molecular scale. It could also be used to test whether electronic components used in spaceflight can withstand radiation, perform three-dimensional imaging of the internal structure of semiconductor chip designs, and potentially develop new cancer treatments and advanced medical imaging techniques.
The team's research paper was published in the journal Matter and Radiation at Extreme.