By far the coolest projects we see are those dealing with high voltages and deep vacuums. Vacuum tubes of all types fall into this category, as do the electron microscopes we see from time to time. The king of all vacuum and electron hacks is the Farnsworth Fusor, a machine that will both transmute the elements and bathe you in neutrons. Fun stuff, and [Daniel] has a great tutorial for building your own.
[Dan]’s fusor is surprisingly simple to make. Obviously, the most important part is the vacuum chamber which in this build is based around a glass oil cup cylinder. With just a few roughly machined parts – the only tool needed to make the metal plates is a drill press – it can hold a low enough vacuum to contain a star in a jar.
For reasons of safety and sanity, [Dan] isn’t running his fusor at a high enough voltage to actually fuse deuterium into helium. This is really just a beautiful, glowey demonstration of what can be done with enough knowledge, the skills, and a handful of parts.
The magnum opus of alchemy was the Philosopher’s stone, a substance that was able to turn common metals into gold. Unlike alchemists, [Carl Willis] might not be poisoning himself in a multitude of ways, but he did build a Farnsworth fusor that’s capable of turning Hydrogen into Helium.
To fuse Hydrogen in his device, [Carl] first evacuates a vacuum chamber. Deuterium (Hydrogen with an added neutron) is injected into the chamber, and a spherical cathode made of Tungsten is charged to 75 kV. The deuterium gas is heated and confined by the cathode and fuses into Helum. The electrostatic confinement of the plasma isn’t very much different from some old CRT tubes. This isn’t a coincidence – both the fusor and CRTs were invented by the same man.
While no fusion experiments – including some billion dollar experiments – have ever produced a net energy gain, this doesn’t mean it’s not an impressive engineering feat. If you’d like to try your hand at building your own fusor, drop by the surprisingly active research forum. There’s a lot of really good projects to look through over there.
[Will Jack] built a heavy water fusion reactor and then won district and regional science fair projects with it. Someone give this man a job!
We looked in on his fusion reactor about a year ago. At the time he had managed to build a magnetic containment field but didn’t have the voltages or the deuterium necessary to achieve fusion. We’ll that’s all changed. Using a boron-10 lined sensor tube he’s managed to detect the rise in neutron counts that would indicate fusion. Remarkable. He’s now working on a refined gas system that will allow him to increase the deuterium purity by cutting down on the leak rate. He mentions a few other hardware improvements such as a new containment unit and an ion source upgrade. Both of these concepts go beyond our knowledge so do make sure to put on your Nuclear Engineering hat while reading through his project update.
Do you ever wonder what projects your neighbors have going on in their basements? [Will Jack’s] neighbors might be surprised to find he’s building a fusion reactor. The first step toward completing a Farsworth-Hirsch Fusor is up and running. The picture above shows heated plasma contained in a magnetic field. Next he just needs to up the voltage and inject some deuterium.
Yeah right! Deuterium, aka heavy water, is extremely rare and very difficult to refine. If you’re not familiar with the substance, you should get your hands on the NOVA episode: Hitler’s Sunken Secrets.
We’re glad to see that [Will Jack] is donning a lead vest for protections. [Will O’Brien] cautioned us about the stray X-rays these things produce when he covered fusors back in 2007.