Simulating the neutron energy spectrum for future deuterium-tritium gas filled magnetized liner inertial fusion experiments on Z

Introducing tritium into the initial gas fill used in the magnetized liner inertial fusion (MagLIF) experiments performed at the Sandia National Laboratories Z machine will enable new neutron energy spectrum measurements to be made. When a trace (~1%) amount of tritium is introduced into the fuel the primary deuterium-deuterium (DD) and deuterium-tritium (DT) fusion signal intensities are expected to be comparable, enabling simultaneous measurements of the DD and DT yield and apparent ion temperature on a single neutron time of flight (nTOF) detector. As the tritium fraction is increased the primary DT signal intensity will quickly surpass that of the DD. Therefore, gated nTOF detectors will be required to measure the full dynamic range of the neutron energy spectrum in high tritium fraction (>10%) experiments. Furthermore, at higher tritium fractions a large number of the primary DT neutrons will scatter both elastically and inelastically off of the beryllium liner and generate a substantial down scattered signal which will act as a background for the primary DD signal. This scattered background signal will make inferring the primary DD yield and apparent ion temperature difficult for high tritium fraction experiments. MCNP simulations of MagLIF implosions with different tritium fractions will be presented and different experimental observables will be considered.