Elastic scattering of neutrons by a nucleus results in what outcome?

Elastic scattering of neutrons by a nucleus results in what outcome?

• A. The neutron slows and the target nucleus recoils.
• B. The nucleus splits releasing gamma.
• C. A photon is emitted with no momentum transfer.
• D. No energy transfer to the nucleus.

Answer: (A)

In elastic scattering, the collision is purely mechanical: the nucleus does not become excited and no energy is carried away by internal states. Because energy and momentum are conserved and no new particles or gamma rays are produced, the only outcomes are a neutron and a recoiling nucleus. The neutron slows down because some of its kinetic energy is transferred to the nucleus, which recoils in response to the momentum transfer. The amount of energy transferred depends on the masses involved, but some recoil energy is always involved, even if small for heavy nuclei. Other possibilities would involve processes beyond elastic scattering. For example, the nucleus splitting or emitting gamma rays would indicate a different interaction (fission or inelastic/radiative processes) rather than elastic scattering. Emitting a photon with no momentum transfer would violate momentum conservation. Saying no energy is transferred to the nucleus contradicts the recoil observed in elastic collisions.

In elastic scattering, the collision is purely mechanical: the nucleus does not become excited and no energy is carried away by internal states. Because energy and momentum are conserved and no new particles or gamma rays are produced, the only outcomes are a neutron and a recoiling nucleus. The neutron slows down because some of its kinetic energy is transferred to the nucleus, which recoils in response to the momentum transfer. The amount of energy transferred depends on the masses involved, but some recoil energy is always involved, even if small for heavy nuclei.

Other possibilities would involve processes beyond elastic scattering. For example, the nucleus splitting or emitting gamma rays would indicate a different interaction (fission or inelastic/radiative processes) rather than elastic scattering. Emitting a photon with no momentum transfer would violate momentum conservation. Saying no energy is transferred to the nucleus contradicts the recoil observed in elastic collisions.