Reinventing the beam: Accelerating the path to clean energy materials

With increased national interest in the expansion of nuclear energy and recent advancements in the development of commercial fusion power plants, developing materials that can withstand the extreme conditions of advanced nuclear fission and fusion technologies is more urgent than ever. 

To address this critical challenge, the University of Wisconsin-Madison’s Ion Beam Laboratory (IBL) has launched several new research initiatives that have driven rapid expansion in both usage and funding, tripling external revenue since 2023.

The first is a high throughput ion irradiation technique, developed by Professor and IBL Director Adrien Couet, that has received support from the U.S. Department of Energy (DOE) Nuclear Science User Facility (NSUF) program and the philanthropic organization Schmidt Sciences for fusion materials discovery and deployment. 

Couet’s team has also joined a Fusion Innovation Research Engine (FIRE) Collaborative, administered by the DOE Fusion Energy Sciences (FES) program, as a subaward to MIT. The FIRE Collaborative was established to advance fusion energy science and technology, accelerating progress towards the first fusion pilot plants.

The IBL is also renovating its third beam line for an advanced materials characterization project led by Assistant Professor and IBL Assistant Director Charles Hirst. The new beam line is funded by an infrastructure grant from the Nuclear Energy University Program (NEUP) within the DOE Office of Nuclear Energy. 

“The way the world’s going, we need nuclear,” says Hirst. “We as nuclear materials scientists can’t stick with the status quo.” 

These new initiatives are changing the way we study nuclear materials. Utilizing innovative methods that are both faster and more thorough, the IBL is developing materials for nuclear and fusion power plants to accelerate the path towards clean energy.

The race for fusion materials

Over the past five years, Couet’s research group, Materials Degradation under Corrosion and Radiation (MaDCoR), has developed a high throughput ion irradiation technique to more efficiently develop materials for fusion science and technology. 

Due to the current momentum of fusion startups, there has been a recent surge in interest for fusion materials. Currently, research on materials degradation in fusion environments is limited because the conditions of those environments are extreme—even more so than fission reactors—and difficult to replicate for testing. 

“We don’t have the materials—they don’t exist,” says Couet. “On the fission side, we’re not at the point where we’re throwing darts at the board—there’s tons of data on the board—but with fusion, there are a lot of darts that are going a little bit everywhere, which is where our high throughput approach is useful.”

The high throughput approach involves optimizing the beam line to irradiate more samples in a shorter amount of time. Ion irradiation is a process that utilizes a particle accelerator to shoot samples with high energy ions, simulating the radiation damage expected in fission or fusion environments. 

While neutron irradiation would more closely emulate a true reactor environment, researchers often opt to irradiate using ions rather than neutrons. Neutron irradiation is a slow and expensive process, sometimes taking multiple years to yield sufficient data. There is also limited access to fission neutrons and no fusion neutron sources capable of simulating neutron irradiation in a fusion reactor anywhere in the world today.

Fortunately, alloy performance ranks similarly under both neutron and ion irradiation. In other words, alloys that behave poorly under ion irradiation typically also behave poorly under neutron irradiation. Researchers can therefore use ion irradiation, which achieves high damage rates much faster, to eliminate underperforming alloys more efficiently. 

However, standard ion irradiation processes still have room for improvement. For example, each round of testing involves an iterative process of mounting the samples, loading them, pulling a vacuum, and letting the samples cool down. Plus, conventional beam lines can only irradiate around 1-4 samples at a time.

“That’s just a geometry problem,” says Nathan Curtis, a graduate student in MaDCoR. “You have one beam, and you can only put so many samples in front of it, so what we’ve been working on is a moving stage inside the beamline that comfortably holds about 20 samples.”

The system enables sequential irradiation of 20 samples without breaking vacuum. Each sample can be independently irradiated at different temperatures, damage rates, and total damage over large irradiation areas, significantly improving throughput and experimental flexibility.

But irradiating more samples at one time is only half the battle. Because the samples are micrometers in thickness, they are analyzed using a transmission electron microscope (TEM), and one sample alone can take an entire day to prep and analyze. That’s why Curtis and his colleagues are investigating advanced screening methods to help rule out samples and select others for further characterization.

“There are reasons we do very high fidelity analysis,” says Curtis, “but just being able to rule out—or know that things perform either poorly or really well—even at a very low fidelity scale, is really valuable.”

A new way to irradiate

On the other end of the IBL, Hirst’s team is building out a new beam line to study how nuclear materials evolve when subject to different combinations of radiation, temperature, and stress. 

The majority of materials research today involves a disjointed process of irradiating materials at elevated temperatures, cooling them down, taking them out, heating them up again, and then pulling the samples to apply stress. The new beam line design will allow for simultaneous irradiating, heating, and pulling to better emulate reactor conditions. 

“The environments in reactors aren’t going to be constant,” says Hirst, pointing out that as reactors continue to advance, the environments will only become more extreme. To accurately understand the effectiveness of both new and existing alloys, the materials must be tested in situ, under fluctuating levels of temperature and stress. Phenomena such as irradiation creep and fatigue will also play a role, particularly in pulsed fusion environments. 

Hirst’s ultimate goal is to create practical tools to inform reactor designers such as maps with applied temperature and stress gradients that chart areas of favorable and unfavorable operating conditions. 

Executing that vision involves overcoming a number of logistical barriers. Because ions can’t travel as far through metals as neutrons can, the material samples have to be very thin.

“We’re shooting KitKat wrappers,” says Hirst. “Essentially, we’re shooting metal foil while we’re pulling it and seeing what happens.”

Thin foil samples are difficult to produce and analyze. Metal foil is easy to come by, but pure metals are too soft to put in the reactor, so researchers use alloys. Making metal alloys into a thin foil without changing their internal structure requires “pickling”, or electropolishing, to dissolve the material in a controlled manner. 

Then, when it comes to irradiating the sample, the onslaught of hydrogen ions can significantly heat the materials as kinetic energy is transferred into thermal energy. Measuring the temperature of such thin samples requires non contact thermal imaging equipment and special windows made from zinc selenide that allow infrared through. 

These logistical challenges have provided experiential learning opportunities for the students in Hirst’s group that are helping design the system to optimize functionality. 

Graduate student Smeet Patel is enhancing the design of the vacuum chamber to maximize the number of viewing ports. He also recently attended the Society for Experimental Mechanics (SEM) conference in Milwaukee to learn about digital image correlation, or using cameras to track the material’s behavior in situ at various points across the sample.

The IBL, then and now

While these new research initiatives bring several custom additions to the beamline, Hirst’s team is also collaborating with National Electrostatic Corporation (NEC) to retrofit components from the dormant right beam line, effectively “resurrecting it from beyond the grave,” says Hirst.

The IBL particle accelerator, installed at UW–Madison in 2002, was originally manufactured by NEC in 1988. NEC started as a UW spinoff, founded by Professor Raymond Herb in the 60s. Based just 5 miles off campus in Middleton, WI, the company now produces custom particle accelerators for institutions around the world. 

Nate Eklof found his start as a technician building and commissioning accelerators for NEC and now brings that experience to his role as the IBL Lab Manager.

“You can think of the IBL as a big machine from the 80s that produces high energy ions and directs them onto our samples,” says Eklof. “The heart of the accelerator system is original, but we’ve done a lot in the last couple of years to replace worn out components and modernize systems.”

The IBL particle accelerator—the part of the systems that produces ions, accelerates them, and delivers them to the end stations for irradiation—has remained largely the same since it was first installed, while custom components have been fitted to the end stations for various experimental research projects.

In recent years, Eklof and Instrumentation Technologist Zack Rielley replaced several crucial subsystems including the vacuum pumps, vacuum gauges, and cooling system. The upgrades have enabled the lab to run more reliably and perform more irradiations.

The IBL now operates regularly as a user facility through the NSUF program. Researchers and companies around the U.S. and across the world submit proposals to the DOE to access the facility, and the IBL team works with them to irradiate their samples. The lab’s capabilities continue to expand at a rapid pace, with user facility revenue from 2025 alone accounting for 29% of all external revenue generated since 2016. 

A garage ion beam

Besides maintenance and operations, Eklof also manages an average of 5 undergraduate students each semester who are hired and trained as lab assistants and accelerator operators. The students spend a semester learning radiation safety protocol to become OSHA-designated radiation workers. They also receive hands-on training to independently operate the accelerator, complete standard operating procedures, and perform maintenance on the vacuum pumps and ion sources.

“It takes about a semester for new students to get trained up so that they can contribute to beam time,” says Eklof. 

Once fully trained, undergraduates get involved in the day-to-day operations of the lab. They often run the beam in the evenings after the instrumentation technicians have left, keeping an eye on the irradiations while they tackle their course work. 

Undergraduates also work on special projects. Nick Merrel, a junior in the Engineering Physics program, built and implemented a vacuum monitoring system with new ion gauge controllers, data acquisition capabilities, and a custom LabVIEW program to replace the outdated analog system. 

Graduate students have the same hands-on opportunities when it comes to their research. Students are encouraged to design their own equipment and build their PhD thesis around niche experiments—the kind of difficult, but high impact research that requires custom setups. 

“I like to call it a garage ion beam,” says Couet, “in the sense that students really get their hands on the machine, get the time they want to develop their own techniques.”

Students’ involvement in the IBL is not limited to push-button operation; they get to leave their mark. In fact, the iconic red body of the IBL was painted by graduate students during an overnight shift at the lab. Some of the IBL’s most important contributions to nuclear science and technology are the practical educational opportunities it provides for UW students. 

“I believe really strongly that the output of a PhD isn’t necessarily your thesis,” says Hirst. “It is the graduate. It is the person themselves.”

Expanding the availability of nuclear energy is going to require a well-trained workforce. The IBL is generating a community of leaders in nuclear science and technology by providing an ideal environment for students to grow as researchers, engineers, and problem solvers. 

Building an ecosystem for collaborative research 

The IBL isn’t the only experimental lab on campus performing novel fission and fusion research. UW–Madison is home to an ecosystem of world-class research facilities all within only a few hundred feet of each other. 

The IBL is housed in the same building as the Pegasus-III Experiment, a low aspect ratio spherical tokamak used for fusion research. The UW Nuclear Reactor (UWNR), a 1 MW TRIGA research reactor, is located right next door, and across the street, there is another fusion facility, the Helically Symmetric eXperiment (HSX), which is the world’s first stellarator optimized for quasi-symmetry.

Aside from the opportunities for collaboration between these on-campus facilities, the IBL actively pursues external partnerships, regularly conducting irradiations for a number of industry partners and for research scientists through the NSUF program. Collaborative research and public-private partnerships are what will propel clean energy science and technology to the next level.

“There’s too much science done in silos,” says Hirst. “I’m very open access, so I want people to come and use it.”

As the world races to decarbonize and meet the unprecedented energy demands of the future, the need for new materials that can withstand extreme radiation, temperature, and mechanical stress has never been greater. The IBL is not just keeping pace, it’s helping set the tempo. By rethinking how we irradiate, test, and characterize materials, the IBL is creating faster, more flexible platforms for discovery and deployment. 

From cutting-edge ion beamlines to hands-on student training, the lab is empowering the next generation of nuclear scientists and engineers. In doing so, it’s accelerating the path to reliable, carbon-free power, pushing fusion and advanced nuclear energy technologies closer to commercial reality. As the clean energy revolution unfolds, the UW-Madison Nuclear Engineering and Engineering Physics Department is ensuring that materials science is not a bottleneck, but a source of breakthrough opportunity.

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