Alphascattering

Alphascattering is a term used in nuclear and particle physics to describe scattering processes in which incident alpha particles (helium nuclei) interact with a target nucleus or matter and are deflected or slowed as a result of the interaction. The studies focus on how the alpha particle's path and energy change as a function of angle and energy, providing information about the structure of the target and the forces at play.

In practice, alphascattering experiments distinguish between elastic and inelastic channels. Elastic alphascattering leaves all particles in their ground states, with only the trajectory altered by Coulomb and nuclear forces. Inelastic alphascattering involves excitations of the target nucleus or the alpha particle, producing characteristic energy losses and gamma or particle emission that reveal details of nuclear excited states and transition strengths.

Mechanisms and modeling. At low to intermediate energies, the scattering is largely governed by the repulsive Coulomb interaction between the positively charged alpha and the target, described by Rutherford-like behavior with deviations arising from nuclear coupling at small impact parameters. At higher energies, the nuclear force contributes significantly, and reaction mechanisms such as compound nucleus formation or direct reactions may appear. The bending and attenuation of the alpha flux are commonly modeled with optical potentials that combine a real part (elastic scattering) and an imaginary part (absorption into non-elastic channels).

Observables and methods. Experiments measure differential cross sections dσ/dΩ as a function of scattering angle and energy. Data are analyzed with partial-wave or optical-model approaches to extract nuclear radii, surface properties, and alpha-nucleus interaction potentials. Alphascattering remains a standard tool for probing nuclear structure and reaction dynamics, complementing other scattering and spectroscopy techniques.