INRS researchers break neutron production record with laser

Quebec researchers recently set a world record by generating the largest neutron flux ever obtained with a laser, a feat that could have practical applications in several fields, including healthcare.

Researchers at the Institut national de la recherche scientifique (INRS) and Infinite Potential Laboratories (IPL) achieved this breakthrough thanks to the Advanced Laser Light Source (ALLS) femtosecond source laboratory, a national infrastructure based at INRS’s Centre Énergie Matériaux Télécommunications, home to Canada’s most powerful laser.

“We tried a mechanism that had already been used by several other groups,” explained Sylvain Fourmaux, a research associate at INRS’s Centre Énergie Matériaux Télécommunications. “The difference is that in Canada, we have a laser that offers a good combination of energy, power, and repetition rate.”

This made it possible to obtain “a neutron flux that is close to what we need for practical applications, which was not the case until now,” he added.

This breakthrough comes after nearly 20 years of work and was made possible by the maturation of the technology needed to achieve it.

Since the details would only be understandable to those with a PhD in nuclear physics, we will simply repeat the explanation provided by INRS:

“(The) approach consists of accelerating electrons in a laser-produced plasma. These electrons are then projected onto a tungsten target, a dense and highly resistant metal, from which gamma rays are produced that induce a photo-nuclear reaction producing an exceptional amount of neutrons.”

The technique generates 100 times more neutrons per second than traditional laser methods, a result described as “unprecedented.”

The potential practical applications of this achievement, on the other hand, are much easier to understand.

Since neutrons are easily absorbed by water, said Professor François Légaré, director of the INRS Center for Energy, Materials and Telecommunications, they could be used to produce ultra-detailed X-rays. And since they are also easily absorbed by lithium, they could enable better imaging (and therefore optimization) of the batteries used in electric cars.

Before this breakthrough, access to a nuclear reactor or particle accelerator was required to obtain sufficient neutrons. The work carried out at INRS and IPL paves the way for “democratization” of access to neutrons, he added, through the use of compact laser systems.

“A laser that fits into a 60-square-meter laboratory is much less complicated than a nuclear reactor,” Légaré explained. “In general, in universities, it’s fairly easy to have a laser in a 60-square-meter laboratory. It’s more complicated to have a nuclear reactor.”

The same technique also produces high quantities of gamma rays, he said, “so we have access to two simultaneous imaging modes, which is called multimodal imaging.”

This innovation, he said, “heralds the advent of compact, fast, and affordable neutron sources with a variety of applications.”

“Many applications are possible in the near future, such as neutron imaging for rapid prototyping, weld inspections, concrete structure assessment, explosive device testing, device quality assurance, radiation resistance assessments, and nuclear fuel inspections,” the authors explain in the journal Nature Communications.

What’s more, they add, “laser systems that meet the required specifications are commercially available, and several existing companies have the necessary expertise to design the laser-material interaction module (…) to create integrated solutions.”

In addition, the authors conclude, “advances in machine learning in complex laser-plasma processes will contribute to the automation of operations.”

–This report by La Presse Canadienne was translated by CityNews