Design of the CMFX Neutron Track Detector Array

CR-39 has been studied extensively in the past for use as a solid state nuclear track detector (SSNTD) for measuring incident particle fluence and energy. Incident neutrons scatter off of hydrogen atoms in the plastic, emitting recoil protons. These protons can generate etchable tracks as they pass through the plastic. The amount of material damage adjacent to the track is dependent on the energy loss of the particle at that point. These tracks can then be etched chemically using a caustic solution such as potassium hydroxide, after which the tracks can be viewed by optical microscopy. Previous plasma experiments have used arrays of SSNTDs that allow for a better understanding of the angular profile of the neutron fluence [R. Przybocki, et. al. Rev. Sci. Instrum. 92, 013504 (2021)]. An array of CR39 plates outside of the (CMFX) vacuum chamber is planned. From this, neutron flux and energy profiles can be determined for the volume of neutron-producing plasma. Details of the CR39 processing procedures as well as the calculations used to obtain volume profiles and preliminary experimental results from deuterium plasmas are presented.