Authors: de Nolfo, G.A. (NASA Goddard Space Flight Center, Greenbelt, MD), A. Bruno (Catholic University of America, Washington DC / NASA Goddard Space Flight Center, Greenbelt, MD), J.G. Mitchell (NASA Goddard Space Flight Center, Greenbelt, MD), Ryan, J.M. (Space Science Center, University of New Hampshire, Durham NH)

In solar flares, neutrons and γ rays are produced by the interaction of accelerated ions that strike the solar atmosphere. While γ rays have been detected for decades with numerous heliospheric missions, the detection and measurement of solar neutrons has been much more elusive. Solar neutrons are important for several reasons related to both fundamental science but also practical applications. They fill a production gap in solar flare observations between the low- and high-energy gamma-ray observations, from which we can access the full energy range of the accelerated (and interacting) ion population within flares. Alongside solar energetic particles, solar neutrons contribute to the radiation environment in space, posing a serious risk to astronauts as we venture to the Moon, Mars, and beyond. Perhaps because they are challenging to detect, solar neutrons have been a much-neglected area of research. That said, they provide fundamental insight into the governing processes of solar flares and the solar interior. To date, less than 20 measurements exist of solar neutrons and this can be attributed to a dearth in technological advancements required to observe solar neutrons above large backgrounds. State-of-the-art neutron spectrometers are rapidly advancing and are likely to transform the field. We discuss the science motivation for solar neutron observations, the technologic advancements to make progress, and highlight several neutron spectrometer developments underway.