Baron Blackett (1897-1974) British physicist. He was awarded a Nobel Prize 1948 for work in cosmic radiation and his perfection of the cloud chamber, an apparatus for tracking ionized particles.
Blackett was born in Croydon, Surrey, and joined the navy 1912; after World War I, he studied science at Cambridge. He held posts at various British academic institutions.
In 1924, working under physicist Ernest Rutherford at Cambridge, Blackett made the first photograph of an atomic transmutation, which was of nitrogen into an oxygen isotope. He continued to develop the cloud chamber and 1932 designed one where photographs of cosmic rays were taken automatically; the device soon confirmed the existence of the positron. Later he discovered particles with a life span of 10-10 sec, which became known as strange particles.
In the 1950s he turned to the study of rock magnetism.