Time-resolved measurement of neutron energy isotropy in a sheared-flow-stabilized Z pinch
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 pl...
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IOP Publishing
2025-01-01
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| Series: | Nuclear Fusion |
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| Online Access: | https://doi.org/10.1088/1741-4326/ada8bf |
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| author | 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 |
| author_facet | 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 |
| author_sort | R.A. Ryan |
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| description | 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 $4\times10^7 \pm 4\times10^6$ neutrons per discharge. Measurements of the neutron energy isotropy under these operating conditions demonstrates the energy of deuteron beams is less than $7.4 \pm 5.6^\mathrm{(stat)} \pm 3.7^\mathrm{(syst)}$ 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. |
| format | Article |
| id | doaj-art-11829deb561b49479202efd46aa8461e |
| institution | Kabale University |
| issn | 0029-5515 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Nuclear Fusion |
| spelling | doaj-art-11829deb561b49479202efd46aa8461e2025-01-31T10:54:08ZengIOP PublishingNuclear Fusion0029-55152025-01-0165202607010.1088/1741-4326/ada8bfTime-resolved measurement of neutron energy isotropy in a sheared-flow-stabilized Z pinchR.A. Ryan0https://orcid.org/0009-0001-7742-1431P.E. Tsai1A.R. Johansen2A.E. Youmans3https://orcid.org/0009-0004-9154-9679D.P. Higginson4https://orcid.org/0000-0002-7699-3788J.M. Mitrani5C.S. Adams6D.A. Sutherland7B. Levitt8https://orcid.org/0009-0006-7408-8342U. Shumlak9https://orcid.org/0000-0002-2918-5446Zap Energy , Everett, WA 98203, United States of AmericaZap Energy , Everett, WA 98203, United States of AmericaAerospace and Energetics Research Program, University of Washington , Seattle, WA 98195, United States of AmericaLawrence Livermore National Laboratory , 7000 East Avenue, Livermore, CA 94550, United States of AmericaLawrence Livermore National Laboratory , 7000 East Avenue, Livermore, CA 94550, United States of AmericaLawrence Livermore National Laboratory , 7000 East Avenue, Livermore, CA 94550, United States of AmericaZap Energy , Everett, WA 98203, United States of AmericaZap Energy , Everett, WA 98203, United States of AmericaZap Energy , Everett, WA 98203, United States of AmericaZap Energy , Everett, WA 98203, United States of America; Aerospace and Energetics Research Program, University of Washington , Seattle, WA 98195, United States of AmericaPrevious 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 $4\times10^7 \pm 4\times10^6$ neutrons per discharge. Measurements of the neutron energy isotropy under these operating conditions demonstrates the energy of deuteron beams is less than $7.4 \pm 5.6^\mathrm{(stat)} \pm 3.7^\mathrm{(syst)}$ 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.https://doi.org/10.1088/1741-4326/ada8bfZ-pinchnuclear fusionneutron diagnosticsplasma diagnosticsflow pinch |
| spellingShingle | 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 Time-resolved measurement of neutron energy isotropy in a sheared-flow-stabilized Z pinch Nuclear Fusion Z-pinch nuclear fusion neutron diagnostics plasma diagnostics flow pinch |
| title | Time-resolved measurement of neutron energy isotropy in a sheared-flow-stabilized Z pinch |
| title_full | Time-resolved measurement of neutron energy isotropy in a sheared-flow-stabilized Z pinch |
| title_fullStr | Time-resolved measurement of neutron energy isotropy in a sheared-flow-stabilized Z pinch |
| title_full_unstemmed | Time-resolved measurement of neutron energy isotropy in a sheared-flow-stabilized Z pinch |
| title_short | Time-resolved measurement of neutron energy isotropy in a sheared-flow-stabilized Z pinch |
| title_sort | time resolved measurement of neutron energy isotropy in a sheared flow stabilized z pinch |
| topic | Z-pinch nuclear fusion neutron diagnostics plasma diagnostics flow pinch |
| url | https://doi.org/10.1088/1741-4326/ada8bf |
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