The Large Hadron Collider (LHC) continues to amaze and delight scientists as it teases apart the most intricate natural phenomena in the universe. It’s just so big, though. Researchers have successfully activated a tiny particle accelerator that’s not even pocket-sized—it could get lost in your pocket. The nanophotonic electron accelerator (NEA) is the size of a small coin, but it could have a big impact.
The nanophotonic electron accelerator is a microchip just a few millimeters across, designed by scientists at Germany’s Friedrich–Alexander University of Erlangen–Nuremberg (FAU). Inside is an even more minuscule vacuum tube, inside which are thousands of microscopic pillars. The chip is designed to accelerate electrons, which are negatively charged, by firing short laser pulses at the pillars. This technology was proposed in 2015, but this is the first time one has been tested.
Electrons inside the NEA accelerate inside a tube measuring just 0.02 inches (0.5 millimeters) long, 54 million times shorter than the 16.8-mile-long beam path of the Large Hadron Collider. The NEA accelerator is an impressive piece of engineering, but the sheer scale of the LHC puts it on a different level. With around 9,000 powerful magnets, the LHC accelerates particles to 99.9% the speed of light before smashing them together.
Accelerator channels inside the chip as seen by scanning electron microscope.
Credit: FAU / Laser Physics
The NEA also produces a magnetic field to accelerate particles, but it’s a product of the laser striking the tiny pillars inside the vacuum tube. The study, now published in Nature, notes that the compact accelerator increased electrons from 28.4 to 40.7 kiloelectron volts, a greater than 40% increase. These particles only have about one-millionth of the energy as particles zipping around the LHC. But no one is aiming to use a coin-sized accelerator to explore the mysteries of particle physics.
The statement from FAU notes that medical applications are top of mind. Specifically, the NEA could be ideal for targeted cancer radiotherapy, which would be much safer for patients than existing methods of delivering radiation. “The dream application would be to place a particle accelerator on an endoscope in order to be able to administer radiotherapy directly at the affected area within the body,” says Tomáš Chlouba, one of the lead authors of the paper. The team is still far from using the micro-accelerator in human medicine, but successfully testing the first nanophotonic system is a big step in that direction.
