Neutron Yield Enhancement Through Gas Admixture and Cathode Radius Variation in a Plasma Focus Device

This study investigates the complex relationship between different cathode radii (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">b</i>) and neutron yield (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Y_{n}$</tex-math> </inline-formula>), for the 2.73-kJ United Nations University/International Centre for Theoretical Physics Plasma Fusion Facility (UNU/ICTP PFF) plasma focus (PF) device when gas admixtures are introduced. The Lee model code is applied to characterize the UNU/ICTP PFF and for optimizing deuterium and argon (D:Ar) neutron production. The latest codes revealed how varying cathode radii and gas admixtures affect <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Y_{n}$</tex-math> </inline-formula> and plasma dynamics. The maximum computed <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Y_{n}$</tex-math> </inline-formula> generated per shot is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2.42\times 10^{7}$</tex-math> </inline-formula> n with beam energy of 80.7 kJ at a gas admixture weight ratio of ca. 19% and the pure D counterpart produced <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$9.57\times 10^{6}$</tex-math> </inline-formula> n with a beam energy of 68.97 kJ, both corresponding to 2.0-cm cathode radii. This shows a significant increase of ca. 153%. The study revealed that <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Y_{\mathrm {th}}$</tex-math> </inline-formula> made a negligible contribution to the total <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Y_{n}$</tex-math> </inline-formula>. The pinch lifetime increases with increasing proportion of Ar gas. As the Ar weight ratio increases, the overall mass of the plasma increases, due to heavier Ar atoms.