A neutron spectrometer for aircraft 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 tantalum.
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.
