Compact sub-kilojoule range fast miniature plasma focus as portable neutron source

Abstract

As a first step toward the development of a compact and portable, quasi-continuous pulsed neutron source, we have demonstrated a 'fast miniature plasma focus (PF) device' as a compact nuclear fusion apparatus. The system operates with deuterium gas and produces an average neutron yield (Y90°) of (1 ± 0.27) × 104 neutrons/shot at ∼70 kA peak discharge current. In the range of 1.5–4 mbar, a distinct and sharp dip in the current derivative signal indicates a strong pinching action with subsequent emission of hard x-rays followed by a neutron pulse. The yield and the time history of the neutrons were measured by both active and passive detection techniques (such as a 3He proportional counter, NE102A plastic scintillator and CR-39 SSNTDs). The overall dimensions of the apparatus, which includes a capacitor bank, sparkgap switch and the focus chamber, are 0.2 m × 0.2 m × 0.5 m and the total mass of the system is ∼25 kg. The scope of this paper is to evaluate/demonstrate the potential of such a fast miniature PF device as a compact and portable fusion apparatus producing neutrons while operating at relatively low energy.