A newly built benchtop neutron generator uses a linear particle accelerator inside an evacuated glass tube to ionize and accelerate pure deuterium into a titanium target. The reaction can produce free neutrons that are slowed by high-density polyethylene and d
For an amateur nuclear experimenter, the jump from making a Geiger counter to producing neutrons is huge. This project closes part of that gap with a benchtop neutron generator built around something deceptively simple: pure deuterium.
The device feeds deuterium into an evacuated glass tube, ionizes it, and accelerates the ions into a titanium target. The first deuterium nuclei that strike the target react to form titanium deuteride, trapping the ions while more accelerated ions continue to hit. From there, nuclear fusion follows.
The fusion reaction mostly forms helium-4. But it can also produce helium-3 and a free neutron—an outcome that matters most for the generator’s purpose. Those neutrons are radiated away and then slowed down by a block of high-density polyethylene. A silver or indium foil wrapped around a Geiger counter tube acts as the detector: the slowed neutrons activate the foil. and the Geiger counter detects the resulting increase in radioactivity.
The heart of the build is a linear particle accelerator housed inside an evacuated glass tube. It relies on two high-voltage power supplies. A 20 kV supply ionizes the deuterium gas fed into the tube. A separate 100 kV supply accelerates the ions emitted from the source into the titanium target.
The target isn’t just mounted in place. It’s surrounded by a cup-shaped electrode designed to capture secondary electrons emitted during impact—part of how the system tries to keep the experiment stable. Still. the most critical requirement is keeping the tube at very low pressure to prevent arcing. achieved through extensive use of an oil diffusion pump.
The proof isn’t theoretical. Radioactivity measurements of the silver and indium foils show the generator did work. When the silver foil was irradiated for five minutes. it generated 175 counts per second after the neutron source was turned off. Looking at how the count rate changed over time. the results suggested a mixture of two silver isotopes being generated: Ag-110 and Ag-108. based on their half-lives.
Irradiating indium produced similar behavior, with an exponential decay in radiation over time.
The project is presented as a new kind of home-scale experiment. and the technical details make clear why: it’s not just a neutron source. it’s a tightly engineered chain—ionization. acceleration. a titanium target. neutron moderation. and foil activation—contained inside a glass tube that must be kept under demanding vacuum conditions.
neutron generator deuterium particle accelerator Geiger counter nuclear physics DIY titanium target oil diffusion pump silver foil activation indium activation helium-3 helium-4 Ag-110 Ag-108
So it’s like a Geiger counter that shoots neutrons now? Cool but also nope.
I saw “deuterium” and immediately thought of like, nuclear war stuff. Why is this even in someone’s house? Also if it’s radiation, how is it “safe” for homeowners.
They say it makes helium-4 and helium-3 and a free neutron… so basically it’s a tiny sun in a box? Like, wouldn’t the helium build up and explode? Not sure, but that oil diffusion pump part sounds sketchy.
Wait, is the detector the foil or the Geiger counter? I’m confused because they’re wrapping a silver or indium foil around a tube and then also measuring counts. 175 counts per second doesn’t sound like much… unless it is, idk. Also arcing prevention with vacuum pumps makes me think it’ll fail in real life.