German scientist, who studied in London (with William Ramsay) and Canada (with Ernest Rutherford) before returning to Germany in 1907.

In 1917, together with Lise Meitner, he discovered protactinium. In the late 1930s he collaborated with Fritz Strassmann (1902-) and in 1938 bombarded uranium with slow neutrons.

Among the products was barium, but it was Meitner (now in sweden) who the next year interpreted the process as nuclear fission. In 1944 Hahn received the Nobel Prize for chemistry.