Chadwick made the first artificial nuclear transformation in 1919, by bombarding an atom with alpha particles, thus leading him to make multiple nuclei studies. In 1932, Chadwick proved the existence of neutrons. After bombarding Beryllium with alpha particles, he saw what he that was gamma radiation being reflected. But upon research, Chadwick discovered that these particles were neutral, naming them neutrons. In 1941, he wrote the MAUD report, inspiring the US to look into the atomic bomb.