Characterization of an ultra-compact neutron source based on an IEC fusion device and its prospective applications in radiography

Abstract

Our group is developing an ultra-compact neutron source based on inertial electrostatic confinement (IEC) fusion device for various applications at Kyoto University. This IEC device is configured from a titanium anode and a molybdenum cathode with diameters of 17 and 6 cm, respectively. A high-intensity neutron source operated in a stable pulse shape is mandatory to increase the system’s reliability. Applying a higher voltage is a straightforward way to increase the neutron yield from the system. However, a contradiction between the increase of the applied voltage and the reduction of the system size limits such a proposal. A three-stage feedthrough system is employed in the developed compact IEC to address this contradiction. A feedback control system was developed and applied to the input and output parameters, such as the applied voltage and the neutron yield, to increase its stability in long-term operation. Characterization of the developed system was performed by scanning the neutron yield as a function of applied voltage and cathode current. To date, a maximum neutron yield of 9.2 × 107n·s–1 at 6.4 kW (80 kV and 80 mA) has been obtained. A study of the feasibility of using the IEC system for neutron radiography was performed. Preliminary analysis of the resulting images showed there was good contrast between the sample and the background. The results suggest that optimization of the experimental parameters is needed to perform higher accuracy neutron radiography.