Neutron Camera with Centimeter Scale Spatial Resolution

In the initial prototype of the compact fusion device (called the Orbitron), deuterium ions orbit around a 100 kV cathode with a co-rotating electron plasma confined by a weak 0.05 T magnetic field. Intersecting elliptical orbits of the ions near the cathode lead to high-energy ion-ion collisions and neutron producing fusion events. However, neutrons are also generated on the surface of the 1 cm radius cathode as the ion orbits decay and collide with deuterium embedded in the cathode surface. To distinguish these fusion events, we have designed a five-pixel neutron camera. Neutrons are collimated with high-density polyethylene and each pixel consists of a pulse-shape discriminating scintillator and photomultiplier tube. Neutron producing experiments have been carried out on the Orbitron. These experiments, supported with particle-in-cell and Monte Carlo N-Particle simulations, show spatial resolution on the order of one centimeter.