Rutherford, Ernest (1871–1937)

New Zealand-born British physicist. He was a pioneer of modern atomic science. His main research was in the field of radioactivity, and he discovered alpha, beta, and gamma rays. He was the first to recognize the nuclear nature of the atom in 1911. He was awarded the Nobel Prize for Chemistry in 1908 for his work in atomic disintegration and the chemistry of radioactive substances.

Rutherford produced the first artificial transformation, changing one element to another (1919) by bombarding nitrogen with alpha particles and getting hydrogen and oxygen. After further research he announced that the nucleus of any atom must contain hydrogen nuclei; at Rutherford's suggestion, the name ‘proton’ was given to the hydrogen nucleus in 1920. He speculated that uncharged particles (neutrons) must also exist in the nucleus. In 1934, using heavy water, Rutherford and his co-workers bombarded deuterium with deuterons and produced tritium. This may be considered the first nuclear fusion reaction. He was knighted in 1914, and created Baron in 1931.

Rutherford was born near Nelson on South Island and studied at Christchurch. In 1895 he went to Britain and became the first research student to work under English physicist J J Thomson at the Cavendish Laboratory, Cambridge. In 1898 Rutherford obtained his first academic position with a professorship at McGill University, Montréal, Canada, which then boasted the best-equipped laboratory in the world. He returned to the UK in 1907, to Manchester University. From 1919 he was director of the Cavendish Laboratory, where he directed the construction of a particle accelerator, and was also professor of ‘natural philosophy’ at the Royal Institution from 1921. Rutherford began investigating radioactivity in 1897 and had by 1900 found three kinds of radioactivity with different penetrating power: alpha, beta, and gamma rays. When he moved to Montréal, he began to use thorium as a source of radioactivity instead of uranium. English chemist Frederick Soddy helped Rutherford identify its decay products, and in 1903 they were able to explain that radioactivity is caused by the breakdown of the atoms to produce a new element. In 1904 Rutherford worked out the series of transformations that radioactive elements undergo and showed that they end as lead. In 1914, Rutherford found that positive rays consist of hydrogen nuclei and that gamma rays are waves that lie beyond X-rays in the electromagnetic spectrum.