Influence of electrodes' geometrical properties on the neutron production rate of a discharge fusion neutron source

Trapping ions, such as deuterium and tritium, inside a potential well to generate neutrons is a well-established technology through electric and magnetic fields via the inertial electrostatic confinement fusion (IECF) and the tokamak, respectively. In the IECF, the straightforward configuration is a concentric cathode connected to a negative bias, surrounded by a grounded anode that serves as a vacuum vessel. Theoretically, neutrons are generated inside the vessel through fusion between ions that are accelerated by applying several tens kV voltage and tens mA current. Many parameters affect the plasma conditions and fusion in the system, hence the neutron production rate (NPR). This study investigates the cathode transparency and the number of apertures effect on NPR. For this end, eleven cathodes were fabricated from stainless steel in three different groups with different transparency and number of apertures. NPRs were investigated as a function of the cathode transparency and number of apertures at low power operating mode similar to 1 kW. Experimental results revealed that higher NPR was produced from lower grid transparency and vice versa; this behavior was explained through beam-surface fusion with grid surface. In addition, a higher NPR was generated from the grid with many apertures; this was attributed to the effect of the deuterium ionization improvement by the number of ionizing electrons through the grid channels.