Estimation of Spatial Distribution of Fusion Reactions in a Discharge‐Driven Fusion Neutron Source

ABSTRACT We quantitatively investigated the spatial distribution of fusion reactions under various discharge conditions in a linear inertial electrostatic confinement fusion (IECF) neutron source. A comparison between spectroscopic measurements and a one‐dimensional Monte‐Carlo simulation of collisional reactions in the plasma revealed that the spatial distribution of fusion reactions between ions and background deuterium molecules follows a Gaussian profile with a FWHM of 100 mm, while that of fusion reactions between fast neutral particles and background deuterium gas molecules appears to be uniform. Furthermore, a comparison between the angular distribution of neutron flux measured in the experiment and particle and heavy ion transport code system (PHITS) calculations reproducing the experimental conditions indicates that these fusion reactions contribute approximately 80% of the total fusion reactions at a discharge current of 10 mA and a discharge voltage of 40 kV, increasing to as much as 96% at 30 mA and 60 kV.