Who identified two distinct types of radioactivity, alpha and beta?

Ernest Rutherford identified two distinct types of radioactivity, which he named alpha and beta radiation.

Working at McGill University in 1899, Rutherford studied the invisible emissions from uranium and found that they behaved differently when passing through materials. One component was easily absorbed by thin metal foils; he called it alpha radiation. The other penetrated much farther and became known as beta radiation. The names came from the first two letters of the Greek alphabet.

Rutherford’s classification built on Henri Becquerel’s discovery that uranium emitted penetrating radiation and Marie Curie’s research establishing radioactivity as a property of matter. Rutherford later recognised a third, more penetrating type discovered by Paul Villard and named it gamma radiation in 1903.

A common mix-up is crediting Marie Curie with identifying alpha and beta radiation because of her major work on radioactivity. Curie helped establish the phenomenon and discovered polonium and radium, but Rutherford performed the experiments that separated and named the two radiation types.