Photo from the Nobel Foundation archive.
Born: 20 October 1891, Manchester, United Kingdom
Died: 24 July 1974, Cambridge, United Kingdom
Affiliation at the time of the award: Liverpool University, Liverpool, United Kingdom
Prize motivation: "for the discovery of the neutron."
Prize share: 1/1
When Herbert Becker and Walter Bothe directed alpha particles (helium nuclei) at beryllium in 1930, a strong, penetrating radiation was emitted. One hypothesis was that this could be high-energy electromagnetic radiation. In 1932, however, James Chadwick proved that it consisted of a neutral particle with about the same mass as a proton. Ernest Rutherford had earlier proposed that such a particle might exist in atomic nuclei. Its existence now proven, it was called a "neutron".
See the list of all Nobel Prizes, awarded for "the greatest benefit to mankind."
In his will, Alfred Nobel left 31 million SEK to found the Nobel Prizes.
Medicine Laureate Shinya Yamanaka talks about the importance of taking risks.