Measured nuclear burn widths for Magnetized Liner Inertial Fusion (MagLIF) experiments*

The Magnetized Liner Inertial Fusion (MagLIF) concept being pursued on the Z machine offers a pathway to generate >1 MJ fusion yields with significant alpha heating on a future machine [1]. Understanding the role of nuclear burn widths can be informative for assessing how MagLIF scales to higher yields. A technique for measuring nuclear burn widths from collinear neutron time-of-flight (nToF) detectors is presented. The widths of measured nToF traces are a function of the nuclear burn width, energy broadening, an instrument response function (IRF), and scattering along the line-of-sight. For each nToF detector, IRFs are measured as a function of the PMT voltage bias and neutron scattering is numerically calculated. At least two collinear nToF detectors at different distances from the neutron source are needed to disambiguate the contributions of nuclear burn width and thermal broadening to the widths of the measured nToF traces. A forward fitting technique [2] designed for simultaneously analyzing multiple nToF traces has been adapted for fitting two collinear nToF detectors on the Z machine. Nuclear burn widths and apparent ion temperatures are calculated from fitted widths of the nToF traces.

 

[1] D.A. Yager-Elorriaga et al. Nucl. Fus. 62 042015 (2022).

[2] J.M. Mitrani et al. Rev. Sci. Instrum. (2024) article in press.

 

Prepared by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. Sandia National Laboratory is managed and operated by NTESS under DOE NNSA contract DE-NA0003525.