Complex sentence: Astatine was synthesised in 1940 by Dale R. Corson, Kenneth Ross MacKenzie, and Emilio Segrè who bombarded bismuth-209 with alpha particles in a cyclotron to produce, after emission of two neutrons, astatine-211.
Split into simpler sentences: Astatine was synthesised in 1940 by Dale R. Corson, Kenneth Ross MacKenzie, and Emilio Segrè. They bombarded bismuth-209 with alpha particles in a cyclotron to produce, after emission of two neutrons, astatine-211.