To achieve big nuclear goals, you have to start small.

neutron generator
  • What’s inside a ball bearing, handgun, or pair of headphones? Neutrons can show us.
  • Making plentiful neutrons is important for medicine, manufacturing, and more.
  • The researchers at Phoenix believe neutron generators will help pave the way for nuclear fusion energy.

The Madison, Wisconsin-based startup Phoenix has scouted a team of nuclear elites for a new frontier: small reactors that can revolutionize medical imaging, munitions scanning, and even non-destructive testing for quality assurance.

And in the longer term, scientists say training people to run neutron generators helps to familiarize and speed up the future of nuclear fusion.

Phoenix’s small reactor uses an age-old idea, but brings it from research programs into the commercial sector. Tiny reactors like NuScale’s are in a different category of tiny altogether—that’s power plant scale, not the small reactors used in physics labs in universities and government-sponsored laboratories. The nearby University of Wisconsin’s Fusion Technology Institute lists medical isotope production as a major near term focus.

That research focuses on protons, but Phoenix wants to generate neutrons for medical use. Hackaday explains:

“Outside of a nucleus, a neutron is unstable, with a half-life of approximately 10 minutes and 11 seconds, after which it beta decays into a proton. Since neutrons cannot exist for extended periods of time outside of a nuclide, this means that free neutrons have to be generated where they are needed.”

The solution is a small reactor that pumps out neutrons like a faucet. In this case, hydrogen isotopes like deuterium and tritium are collided in a meter-long particle accelerator where they fuse and are harvested from a constantly replenished supply of reactive gas.

In 2019, a startup called SHINE used that neutron flux reactor faucet to set a new record for a fusion reaction in a steady-state system, churning out 46 trillion neutrons per second. The resulting neutron streams can enable and bring down the cost of neutron imaging, a form of radiography like an X-ray, but better for certain applications.

weapons. Like so:

An X-ray and “N-ray” image of the same jar of staples, via Phoenix Neutron Imaging.

Phoenix’s president, Evan Sengbusch, tells Popular Mechanics by email that Phoenix has two big goals at any given time: “first, how we can use it immediately, at its current performance levels, to solve problems […]; second, how we can push ourselves to the next level to solve tomorrow’s problems.”

Giant, experimental reactors like ITER have the potential to completely change energy, but that project uses the most cutting-edge research from around the world. ITER doesn’t seek to generate new research. Phoenix wants to do both.

“We’re not satisfied with just deploying our technology in a commercially profitable manner—our goal is to constantly strive for revolutionary, not incremental, advances that will open up entirely new markets that don’t even exist today,” Sengbusch says.

Sengbusch views neutron streams, which are empowered by small particle accelerators, as a necessary step to the long-term goal of fusion reactors, including the giant one at ITER and dozens of others around the U.S. The neutron record is one example of near-term demand toward longer term nuclear goals.

“If not for the technology developed at Phoenix and with our partners at SHINE Medical Technologies, the world would soon be facing massive shortages of these life-saving agents,” Sengbusch says. “[T]he sooner we can get fusion technologies to be utilized regularly in mainstream commercial applications, the sooner we’ll be able to take the technology to the next level for the production of clean and abundant fusion energy.”