Extension of the neutron scatter camera sensitivity to the ∼10-200 MeV neutron energy range

Rev Sci Instrum. 2019 May;90(5):053305. doi: 10.1063/1.5091715.

Abstract

The Neutron Scatter Camera (NSC) is a neutron spectrometer and imager that has been developed and improved by the Sandia National Laboratories for several years. Built for special nuclear material searches, the instrument was configured by the design to reconstruct neutron sources within the fission energy range 1-10 MeV. In this work, we present modifications that attempt to extend the NSC sensitivity to neutron energies in the range ∼10-200 MeV and discuss the corresponding consequences for the event processing. We present simulation results that manifest important aspects of the NSC response to those intermediate energy neutrons. The simulation results also evidence that the instrument's spectroscopic capabilities severely deteriorate at those energies, mainly due to the uncertainties in measuring energy, time, and distance between the two neutron scattering interactions. This work is motivated by the need to characterize neutron fluxes at particle accelerators as they may represent important backgrounds for neutrino experiments.