Development of the Optimized Solar Neutron Tracking (SONTRAC) Instrument

Solar flares are known to accelerate charged particles up to high energies. If those particles precipitate downward toward the Sun, the accelerated ions can produce secondary neutrons via interactions with the dense plasma of the chromosphere and photosphere. Owing to their low interaction cross sections and brief lifetime, solar neutrons are among the least-measured products of solar flare acceleration. To fill this gap in measurement, we are developing the SOlar Neutron TRACking (SONTRAC) instrument, a novel imaging neutron spectrometer utilizing a scintillating fiber hodoscope read out by miniature silicon photomultipliers. In this presentation, we describe the refinement and optimization of the SONTRAC instrument based on lessons learned from the previous generation SONTRAC design. At the end of this development cycle, we plan to have a fully optimized instrument suitable for proposal to a variety of mission opportunities.