Portable Dense Plasma Focus Neutron Source for Active Interrogation Applications

The reliable detection of special nuclear materials continues to be a primary goal of national security programs conducted by Defense Nuclear Nonproliferation agencies. While these programs are diverse, many share a core need for a small, robust pulsed neutron generator. This project addresses this need by building a portable dense plasma focus (DPF) neutron source. DPF technology offers many benefits that are infeasible using conventional neutron sources: it can generate intense neutron pulses, operate at relatively low voltage, and be scaled to a lightweight form factor. Large-scale DPF sources produce prolific neutron radiation but require heavy machinery for transport and are therefore not ideal for mobile applications. Alternatively, compact DPF systems can be fabricated that are easily transported by human operators and generate sufficient neutron output to accomplish mobile active interrogation missions. Recently, researchers at Mission Support and Test Services (MSTS) have constructed a bench-top DPF system to produce neutron radiation. The system comprises commercially available high voltage power supplies, capacitors, and cold-cathode thyratron switches and weighs approximately 25 kg. The system draws approximately 750 Wand can be powered using lithium-ion battery packs. A custom plasma process chamber was designed using hybrid PIC-MHD modeling software and constructed using off-the-shelf components. A control system was implemented on a microcontroller platform to discharge the DPF source with a repetition rate up to 0.2 Hz. A suite of neutron yield and time-of- flight diagnostics was used to measure the radiation output of the portable DPF source.