The magnetic recoil spectrometer (MRSt) for time-resolved measurements of the neutron spectrum at the National Ignition Facility (NIF)

J A Frenje; T J Hilsabeck; C W Wink; P Bell; R Bionta; C Cerjan; M Gatu Johnson; J D Kilkenny; C K Li; F H Séguin; R D Petrasso

doi:10.1063/1.4959164

The magnetic recoil spectrometer (MRSt) for time-resolved measurements of the neutron spectrum at the National Ignition Facility (NIF)

Rev Sci Instrum. 2016 Nov;87(11):11D806. doi: 10.1063/1.4959164.

Authors

J A Frenje¹, T J Hilsabeck², C W Wink¹, P Bell³, R Bionta³, C Cerjan³, M Gatu Johnson¹, J D Kilkenny², C K Li¹, F H Séguin¹, R D Petrasso¹

Affiliations

¹ Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
² General Atomics, San Diego, California 92186, USA.
³ Lawrence Livermore National Laboratory, Livermore, California 94550, USA.

PMID: 27910467
DOI: 10.1063/1.4959164

Abstract

The next-generation magnetic recoil spectrometer for time-resolved measurements of the neutron spectrum has been conceptually designed for the National Ignition Facility. This spectrometer, called MRSt, represents a paradigm shift in our thinking about neutron spectrometry for inertial confinement fusion applications, as it will provide simultaneously information about the burn history and time evolution of areal density (ρR), apparent ion temperature (T_i), yield (Y_n), and macroscopic flows during burn. From this type of data, an assessment of the evolution of the fuel assembly, hotspot, and alpha heating can be made. According to simulations, the MRSt will provide accurate data with a time resolution of ∼20 ps and energy resolution of ∼100 keV for total neutron yields above ∼10¹⁶. At lower yields, the diagnostic will be operated at a higher-efficiency, lower-energy-resolution mode to provide a time resolution of ∼20 ps.