Alpha particle types: eventually named alpha, beta, and gamma by Rutherford, based on penetration of objects and deflection by a magnetic field. Alpha rays were defined by Rutherford as those having the lowest penetration of ordinary objects. Rutherford's work also included measurements of the ratio of an alpha particle's mass to its charge, which led him to the hypothesis that alpha particles were doubly charged helium ions (later shown to be bare helium nuclei). In 1907, Ernest Rutherford and Thomas Royds finally proved that alpha particles were indeed helium ions. To do this they allowed alpha particles to penetrate a very thin
Light scattering by particles Light scattering by particles Light scattering by particles is the process by which small particles (e.g. ice crystals, dust, atmospheric particulates, cosmic dust, and blood cells) cause optical phenomena, such as rainbows, the blue color of the sky, and halos. Maxwell's equations are the basis of theoretical and computational methods describing light scattering, but since exact solutions to Maxwell's equations are only known for selected geometries (such as spherical particle), light scattering by particles is a branch of computational electromagnetics dealing with electromagnetic radiation scattering and absorption by particles. In case of geometries for which analytical solutions are known (such