The next-generation Magnetic Recoil Spectrometer for time-resolved measurement of the neutron spectrum at the National Ignition Facility (NIF)

The next-generation magnetic recoil spectrometer (MRSt) for time-resolved measurements of the neutron spectrum has been designed for the NIF. This spectrometer represents a paradigm shift in our thinking about neutron spectrometry for ICF applications, as it will provide simultaneously information about the burn history and time evolution of areal density, apparent ion temperature, yield and macroscopic flows during burn. From this type of data, an assessment of the evolution of hot-spot formation and fuel assembly can be made. According to simulations, the MRSt will provide accurate data with a time resolution of ∼20 ps and energy resolution of ∼200 keV for neutron yields above ∼1e16. At lower yields, the diagnostic will be operated at a higher-efficiency, lower-energy-resolution mode to provide a time resolution of ∼40 ps. As the discussed in this presentation, the key aspects of the MRSt functionality have also been experimentally demonstrated. The work was supported by DOE, LLNL and LLE.