Neutron spectrometry in space and aviation with a compact scintillator-based detector

Fast neutrons are produced from cosmic ray interactions with matter posing particular dosimetric challenges for aviation and space exploration. Progress towards a compact detector system suitable for measurements of cosmic ray induced neutrons with energies up to 120 MeV is presented. The detector was comprised of a 6 mm × 6 mm × 120 mm prism of EJ-276 scintillator and a pair of MicroFC-60035 silicon photomultipliers, coupled with a digital data acquisition system. A comparison was made of pulse shape discrimination capabilities and light output resolution for single and dual silicon photomultiplier detector systems. The dual SiPM detector was characterised in mono-energetic fast neutron fields between 2.5-19.0 MeV. The simulation of detector response functions with Geant4 was explored, using measurements in mono-energetic fields to derive scaling and broadening parameters. Quasi-monoenergetic detector response functions were measured for neutrons with energies up to 16 MeV using Time-of-Flight techniques, and were used to demonstrate the spectroscopic capabilities of the prototype device through the unfolding of known neutron fields.