Record setting electron beam: 5 times stronger than its predecessor

Scientists have created ultra-train electron beams with five times the peak currents than any other similar beam on Earth.

This achievement, as described in a paper published in a physical review letter, addresses one of the epic challenges of particle accelerators and beam physics, opening the door for new discoveries in a wide range of science fields, including quantum chemistry, astrophysics, and material science.

“Not only can you create such a powerful electron beam, it can also control the beam in a customizable, on-demand way. That means Claudio Emma, ​​a staff scientist at the Department of Energy’s SLAC National Accelerator Laboratory, says Claudio Emma, ​​a Slac scientist researcher at Slac, a scientist facility at SLAC, a new study.

Power balance

As outlined in the Accelerator and Beam Physics Roadmap published in 2022, to the present, one of the biggest challenges for physicists, it was producing extremely powerful electron beams while maintaining beam quality.

Traditionally, microwave fields have been used to compress and focus the electron beam. Because electrons in the field are distorted, the electrons in the rear have more energy than the electrons in the front. It’s like a runner staggering at the start of a track race, Emma explained.

“We then wind and send them, the electrons on the back catch up with the electrons in the front, and finally, a lot of electrons are combined in the concentrated beam.”

The problem with this approach is that as they accelerate, the quality of the beam deteriorates as electrons emit radiation and lose energy. This creates a trade-off between beam energy and quality. “We cannot apply traditional methods to compress bundles of electrons on the submicron scale, but beam quality is also preserved,” Emma said.

Laser for victory

To solve this problem, SLAC researchers compressed billions of electrons to less than one micrometer using laser-based geometry techniques originally developed for X-ray-free electron lasers, such as SLAC’s LINAC coherent light source (LCL).

“The big advantage of using lasers is that they can apply energy modulation that is much more accurate than what you can do in a microwave field,” Emma said.

But not only fire some lasers through the tunnel, it’s not that easy. “There is a machine of 1 km long and the laser interacts with the beam in the first 10 meters, so the shape needs to be accurately correct. Then you need to transport the beam to an additional kilometer without losing this modulation. “So it wasn’t easy.”

After cleverly testing laser formation techniques for several months, Emma and his team were able to repeatedly generate petawatt-peak-powered electron beams, which are about five times more current than previously achieved.

An incredible new tool

This new beam allows scientists to examine an entire series of natural phenomena, including testing hypotheses in quantum physics, materials science and astrophysics.

For example, astrophysics allows this beam to be directed at a solid or gas target to create filaments similar to those found on stars. “Scientists know that these filaments occur, but now we can test how they occur and evolve in our labs at levels of power they didn’t have before,” Emma said.

FACET-II researchers have already applied to advances in plasma wake field technology, hitting more powerful beams. Emma is particularly excited by the prospect of compressing these beams further to create attosecond light pulses, further increasing the current attosecond capabilities of LCLS, and promoting even more pioneering science.

“If you have a beam as a high speed camera, there are also very short, light pulses, and suddenly there are two complementary probes,” Emma explained. “It’s a unique ability and we can do a lot with it.”

Emma and his colleagues are excited by the prospects this new electron beam brings.

“Facet-II has a really exciting and interesting facility where people can come and do experiments,” he said. “If you need extreme beams, have the tools and let’s work together.”