Design of a multi-detector, single line-of-sight, time-of-flight system to measure time-resolved neutron energy spectra

• Published in: Review of scientific instruments Vol. 93; no. 11; pp. 113528 - 113532
• Main Authors: Schlossberg, D. J., Moore, A. S., Kallman, J. S., Lowry, M., Eckart, M. J., Hartouni, E. P., Hilsabeck, T. J., Kerr, S. M., Kilkenny, J. D.
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 01.11.2022; American Institute of Physics (AIP)
• Subjects: Algorithms; Deuterium; Energy spectra; Evolution; Inertial confinement fusion; INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; MATHEMATICS AND COMPUTING; Monte Carlo methods; neutron detectors; neutron emission; Neutron spectra; neutron spectroscopy; plasma confinement; plasma diagnostics; Plasmas (physics); thermonuclear fusion; Time measurement; Tritium
• ISSN: 0034-6748; 1089-7623; 1527-2400; 1089-7623
• DOI: 10.1063/5.0101874

In the dynamic environment of burning, thermonuclear deuterium–tritium plasmas, diagnosing the time-resolved neutron energy spectrum is of critical importance. Strategies exist for this diagnosis in magnetic confinement fusion plasmas, which presently have a lifetime of ∼1012 longer than inertial confinement fusion (ICF) plasmas. Here, we present a novel concept for a simple, precise, and scale-able diagnostic to measure time-resolved neutron spectra in ICF plasmas. The concept leverages general tomographic reconstruction techniques adapted to time-of-flight parameter space, and then employs an updated Monte Carlo algorithm and National Ignition Facility-relevant constraints to reconstruct the time-evolving neutron energy spectrum. Reconstructed spectra of the primary 14.028 MeV nDT peak are in good agreement with the exact synthetic spectra. The technique is also used to reconstruct the time-evolving downscattered spectrum, although the present implementation shows significantly more error.