Neutron Science

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What are Neutrons?


Visualization of a Neutron

A neutron is one of the fundamental particles that make up matter. This uncharged particle exists in the nucleus of a typical atom, along with its positively charged counterpart, the proton. Protons and neutrons each have about the same mass, and both can exist as free particles away from the nucleus. In the universe, neutrons are abundant, making up more than half of all visible matter.

Properties of Neutrons

  • Neutrons are NEUTRAL particles. They
    • are highly penetrating,
    • can be used as nondestructive probes, and
    • can be used to study samples in severe environments
  • Neutrons have a MAGNETIC moment. They can be used to
    • study microscopic magnetic structure,
    • study magnetic fluctuations, and
    • develop magnetic materials
  • Neutrons have SPIN. They can be
    • formed into polarized neutron beams,
    • used to study nuclear (atomic) orientation, and
    • used for coherent and incoherent scattering.
  • The ENERGIES of thermal neutrons are similar to the energies of elementary excitations in solids. Both have similar
    • molecular vibrations,
    • lattice modes, and
    • dynamics of atomic motion.
  • The WAVELENGTHS of neutrons are similar to atomic spacings. They can determine
    • structural sensitivity,
    • structural information from 10-13 to 10-4 cm, and
    • crystal structures and atomic spacings.
  • Neutrons "see" NUCLEI. They
    • are sensitive to light atoms,
    • can exploit isotopic substitution, and
    • can use contrast variation to differentiate complex molecular structures.
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