Dodecahedron neutron spectrometer with aluminum proton absorber for spacecraft

Abstract

A neutron spectrometer for spacecraft is provided by a series of substrates covered by a solid-state detector stacked on an absorbing layer. As many as 12 substrates that convert neutrons to protons are covered by a layer of absorbing material, acting as a proton absorber, with the detector placed within the layer to count protons passing through the absorbing layer. By using 12 detectors the range of neutron energies are covered. The preferred dodecahedron embodiment of the neutron spectrometer is a solid, polyethylene dodecahedron assembly with 12 surface facets covered by a solid-state detector stacked on an absorbing layer composed of aluminum. Each absorbing layer is constructed with a different thickness according to the minimum and maximum energies of neutrons in the spectrum. In this arrangement, each of the 12 surface pentagon-shaped facets provides a polyethylene substrate to convert neutrons to protons, covered by a layer of absorbing material, acting as a proton absorber, with the detector stacked on the absorbing layer to count protons passing through the absorbing layer. The dodecahedron assembly is housed concentrically within a titanium spherical shell that serves as an outer shield. The dodecahedron embodiment is sufficiently lightweight to be suitable for airborne and satellite applications.