Bidding Farewell to Fusor

by Gunnar Mein

7 years ago, I was working as a programming and science teacher at Eastside Preparatory School, an independent school for grades 5-12 in Kirkland, WA. I wanted to create a program that would show students that with real engagement and effort, they would be able to do amazing things. All I needed was a project. After reading about a teenage scientist who had built a Fusor, I decided that we should pursue building one.

What is a Fusor, you ask? In brief, it is an amateur nuclear fusion reactor. The proper scientific name for it is “electrostatic inertial confinement fusion reactor”. Yes, it is real, it has been around since the days of Philo Farnsworth in the sixties, and you can prove that fusion happens by measuring the neutron output of the machine. No, it is not commercially interesting because it consumes more energy than it generates. But that also implies that things stop when you pull the plug – a desirable property in a school project! Fusors also don’t need any radioactive material to work.

How does it achieve Fusion? You make a vacuum, create an electric potential difference of 35,000 Volts, and then feed deuterium (heavy hydrogen) ions into that space. The electric field will accelerate the ions into the middle of the vacuum chamber in about 50 nanoseconds, and when two of them collide head-on, they will fuse, giving off protons and neutrons and some other things – including serious amounts of X-rays – in the process. I set out to recruit students over some Dixie’s BBQ, and in September of that year I met Dr. Charles Whitmer, a nuclear physicist and mathematician who would become my co-conspirator for the next 7 years.

To say that we didn’t really know what we were doing in the first year would be an understatement. What is a workable vacuum chamber? Where do we get one? How do we generate 35,000 Volts? Can you buy a supply that does that, or do we have to build one? How would we inject the gas? How do we shield ourselves from the resulting X-rays and neutrons? How do we keep 30 (!) students productive and safe? We researched. And worked. And learned. And built, albeit slowly.

Building a Fusor with high school students is a different endeavor than doing it with a private group. We valued safety and learning over progress, time after time, sometimes to the frustration of some of our more eager students. We ran countless experiments over the years. We built significant modeling software, and students wrote two research papers. A freshmen controlled a high-voltage experiment over VPN from her home.

Fusor, in the way we went about it, was very much a project of our time – it could not have happened without internet forums, a global economy, eBay, Amazon, and small and crazy powerful computers. And as with many things that you learn about while you are doing them, we took a lot longer than we expected. After four years, I told Dr. Whitmer that my time at EPS was going to come to an end after year six. And then COVID happened, and we lost a year. Oh, we did great modeling and research work in that time, and students learned a lot about all kinds of subjects from relativity to quantum physics to the basics of Arduinos. But in the end, remote learning time cannot replace hand-on work time on a project like this. And after year seven, the school is now ready to move on.

We didn’t achieve fusion - the project would probably be at least another year away from it. What did we learn from our time on Fusor? Many of our students found some moment in the project when it was their turn to take the torch and move a vital part forward. Those growth-spurts in responsibility and capability are probably the most rewarding for me to remember. The shared experience of “we don’t know how to do that … yet”, and working through problems together to eventually succeed. The idea that over fifty students took massive amounts of time to teach themselves physics and work in a group toward a whole that was decidedly bigger than any of them could have individually pursued, all for no credit. As a famously no-nonsense tech industry parent put it when he visited us, Fusor was indeed “probably not a waste of time.”

I will always cherish the time we had on this project, and that the school trusted us enough to let us do it in the first place. The idea for our company,, was born out of my experiences on Fusor. Because when you give students the right tools and ask them to apply themselves, amazing things can happen.

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