Time-resolved measurement of neutron energy isotropy in a sheared-flow-stabilized Z pinch
Year: 2025
Type: article
Abstract: Previous measurements of neutron energy using fast plastic scintillators while operating the Fusion Z Pinch Experiment (FuZE) constrained the energy of any yield-producing deuteron beams to less than 4.65 keV. FuZE has since been operated at increasingly higher input power, resulting in increased plasma current and larger fusion neutron yields. A detailed experimental study of the neutron energy isotropy in these regimes applies more stringent limits to possible contributions from beam-target fusion. The FuZE device operated at −25 kV charge voltage has resulted in average plasma currents of 370 kA and D–D fusion neutron yields of 4 × 10 7 ± 4 × 10 6 neutrons per discharge. Measurements of the neutron energy isotropy under these operating conditions demonstrates the energy of deuteron beams is less than 7.4 ± 5.6 ( stat ) ± 3.7 ( syst ) keV. Characterization of the detector response has reduced the number of free parameters in the fit of the neutron energy distribution, improving the confidence in the forward-fit method. Gamma backgrounds have been measured and the impact of these contributions on the isotropy results have been studied. Additionally, a time dependent measurement of the isotropy has been resolved for the first time, indicating increases to possible deuteron beam energies at late times. This suggests the possible growth of m = 0 instabilities at the end of the main radiation event but confirms that the majority of the neutron production exhibits isotropy consistent with thermonuclear origin.
Source: Nuclear Fusion
Authors: R.A. Ryan, P.E. Tsai, A.R. Johansen, A.E. Youmans, D.P. Higginson, J.M. Mitrani, C.S. Adams, D.A. Sutherland, B. Levitt, U. Shumlak
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,595
OpenAlex ID: W4407049751