Precise control of one of the most powerful lasers in the world was required to accelerate electrons to the highest energies ever recorded using a compact accelerator. What kind of laser are we talking? A petawatt laser. Yeah, that probably isn’t used to play with cats.
The laser-plasma accelerator is a new class of particle accelerators. Physicists believe the miles-long accelerators will be a thing of the past soon. These suckers can fit right on your table.
Researchers used electrons inside a nine-centimeter long tube of plasma to achieve the new world record. The laser-plasma accelerator produced an acceleration energy of 4.25 giga-electron volts.
According to a Berkeley press release, “The acceleration over such a short distance corresponds to an energy gradient 1000 times greater than traditional particle accelerators and marks a world record energy for laser-plasma accelerators.”
Why is it so much greater than a traditional accelerator such as the Large Hadron Collider at CERN? The LHC has a circumference of about 17 miles and uses electric fields inside a metal cavity to launch particles. This works great to about 100 mega-electron volts. After that, the metal cavity starts to break apart and we all end up in an episode of Flash.
But, the LHC also doesn’t use one of the strongest lasers in the world to help boost the particles.
I mentioned the laser above, but let’s take a closer look. It’s called the BELLA (Berkeley Lab Laser Accelerator) and produces a quadrillion watts of power (petawatt).
“It is an extraordinary achievement for Dr. Leemans and his team to produce this record-breaking result in their first operational campaign with BELLA,” says Dr. James Symons, associate laboratory director for Physical Sciences at Berkeley Lab.
It took a careful aim of the powerful laser for the experiment to even happen. “We’re forcing this laser beam into a 500 micron hole about 14 meters away,” Leemans says.
Before Leemans and his team took aim at the small tube of plasma, they ran several computer simulations to test their setup. You can see one such simulation below. It shows the plasma wakefield as it “evolves” inside the 9 centimeter long tube.
“Small changes in the setup give you big perturbations,” says Eric Esarey, senior science advisor for the Accelerator Technology and Applied Physics Division at Berkeley Lab, leader of the theory team. “We’re homing in on the regions of operation and the best ways to control the accelerator.”
Leemans’ wants to go even bigger. His next goal? 10 giga-electron volts. But, Leemans and his fellow researchers will need tighten up their plasma channel to handle the energy.