Aside from flashbacks the hit Netflix series Breaking Bad may have conjured up, most of us have probably happily forgotten what we learned in chemistry class at school.
So here’s a quick synopsis: Chemistry is concerned with the building blocks of our physical world, such as atoms, and the changes they undergo. An atom consists of a nucleus of protons and neutrons surrounded by a cloud of electrons.
Aerial view of the European Spallation Neutron Source in 2021. Perry Nordeng
Free the neutrons
Now for something that chemistry might not have taught us in high school: The humble neutron found at the nucleus of every atom except hydrogen can — if manipulated properly — shed light on everything from the climate crisis to energy to health and quantum computing.
One such pathway is a rather spectacular process called spallation, in which high-energy particles destabilize the atomic nucleus, which in turn releases some of the neutrons that are there.
When these newly released neutrons are harnessed, they can be used like X-rays to image the internal structure of materials.
The European Spallation Source (ESS), currently under construction in Lund, Sweden, is scheduled to go online in 2027. Once it reaches its full specifications, its unprecedented flux and spectral range will make it the most powerful and versatile neutron source for science in the world.
The purpose of the facility, said Jimmy Binderup Andersen, head of innovation and industry at ESS, “is to produce neutrons, a beam of neutrons to be used for scientific purposes.”
Once the facility is operational, scientists from across Europe and the rest of the world will be able to use its 15 different beamlines for basic research.
Not x-ray
According to Andersen, a neutron beam “is not the same as an X-ray, but it is complementary and uses some of the same physical laws”.
Like X-rays, neutrons can be used to study materials and biological systems. However, they interact with materials in different ways than the photons in high-energy X-rays, and therefore provide different types of information about their targets.
For example, neutron beams can reveal something about the inner dynamics of lithium-ion batteries, reveal hidden details of ancient artefacts or elucidate the mechanisms of antibiotic resistance in bacteria. They can also be used to research basic physics. It almost seems like asking a question: What can’t they do?
neutron bombardment
The EU-funded BrightnESS 2 project, co-ordinated in part by Andersen, has shared technologies developed for the ESS with industry in Europe to help society at large. For example, some of the energy systems developed for the ESS beamlines could be useful for renewable energy technologies such as wind turbines.
Recently, the ESS was contacted by a European semiconductor manufacturer interested in the radiation fields that the neutron source can produce. The world we live in is constantly bombarded with neutrons, produced when high-energy particles from outer space, such as cosmic rays from the sun, collide with Earth’s atmosphere. Over time, this stress can damage electrical components.
The ESS can mimic this neutron bombardment, but on a much faster time scale, so it can be used to test the durability of critical electrical components, such as those used in airplanes, wind turbines and spacecraft.
Now ESS is collaborating with other research institutes and companies to find a possible future use of a facility like ESS to address such specific industry needs.
ESS 2.0
Although the ESS is still under construction, scientists are already working on modernizing the facility.
When the ESS first opens it will have a moderator, but the EU-funded HighNESS project is developing a second moderator system. The moderators slow down the neutrons produced in the spallation process to an energy level that the scientific instruments can use.
“The neutron energy is really important in a neutron facility because depending on the neutron energy you can do different kinds of physics,” said Valentina Santoro, coordinator of the HighNESS project.
While the first moderator will deliver a very bright, i.e. very focused, neutron beam, the source developed within the HighNESS project will deliver a high intensity. In other words, a large number of neutrons.
The two moderators allow scientists to study different aspects of the dynamics and structure of materials such as polymers, biomolecules, liquid metals and batteries.
A basic mystery
The second moderator also enables explorations of basic physics to see for the first time how a neutron becomes an antineutron.
“This is very interesting because you’re observing a phenomenon where matter becomes antimatter,” said Santoro, a particle physicist at the ESS. “By observing something like this, you can understand one of the greatest unsolved mysteries – why there is more matter than antimatter in the universe.”
This experiment can only be done at the ESS, Santoro said, because it requires a large number of neutrons and the ESS will have the highest number in the world.
“You just need a neutron that becomes an antineutron, and that’s all. They found this process where matter becomes antimatter,” said Santoro.
The research in this article was funded by the EU. This article was originally published in Horizon, the EU research and innovation magazine.