Which category includes neutrons with energies greater than 20 MeV?

Which category includes neutrons with energies greater than 20 MeV?

• A. Relativistic Neutrons
• B. Thermal Neutrons
• C. Slow Neutrons
• D. Epithermal Neutrons

Answer: (A)

Neutron energies are grouped by how fast they move, which mirrors their kinetic energy. Thermal neutrons sit around 0.025 eV, epithermal neutrons span from roughly 0.1 eV up to tens of keV, and fast neutrons cover the MeV range. When energies rise above about 20 MeV, the neutron’s speed is a sizable fraction of the speed of light, so relativistic effects become important in describing their behavior. In many practice contexts, that high-energy end is labeled as relativistic neutrons. So neutrons with energies greater than 20 MeV are categorized as relativistic neutrons. Thermal, slow, and epithermal neutrons occupy ranges well below this energy, which is why they don’t apply here.

Neutron energies are grouped by how fast they move, which mirrors their kinetic energy. Thermal neutrons sit around 0.025 eV, epithermal neutrons span from roughly 0.1 eV up to tens of keV, and fast neutrons cover the MeV range. When energies rise above about 20 MeV, the neutron’s speed is a sizable fraction of the speed of light, so relativistic effects become important in describing their behavior. In many practice contexts, that high-energy end is labeled as relativistic neutrons. So neutrons with energies greater than 20 MeV are categorized as relativistic neutrons. Thermal, slow, and epithermal neutrons occupy ranges well below this energy, which is why they don’t apply here.