Progress in the Design of a Spectrometric Neutron Camera for SPARC

The SPARC tokamak is now under construction in Devens, Massachusetts and is predicted to robustly enter the burning plasma regime (Qp > 5) in DT operation [Creely et al. 2020]. Neutron cameras have been fielded on a variety of other toroidal fusion devices (JET, TFTR, LHD, MAST-U) in order to make spatially resolved measurements of neutron emission. SPARC is planning to deploy a neutron camera using spectrometric detectors in order to measure both the neutron emissivity, ion temperature profile, and possibly non-thermal spectral features. We present recent progress in the design of this camera, specifically the design of the spectrometric detector units. A combination of chemical vapor deposition single-crystal diamond detectors and deuterium-based liquid organic scintillators is being considered to cover SPARC's large dynamic range and provide reliable spectrometric information. Recent laboratory testing has included the use of DT and DD neutron generators for comparing deuterium and hydrogen based scintillators, as well as generator emission characterization using diamond detectors. We present results from neutronics simulations using OpenMC [Romano et al. 2015] of the proposed design configuration, and discuss the use of spectrum unfolding and tomography techniques being considered.