John Douglas Cockcroft
Cockcroft, John Douglas (1897-1967), a British physicist, won the 1951 Nobel Prize in physics, along with physicist Ernest Thomas Sinton Walton. The two designed the first particle accelerator capable of splitting the atom and used the machine to change one element to another. Cockcroft played a major role in overseeing the development of nuclear power in England.
Cockcroft was the eldest of five sons born to John Arthur and Annie Maud Fielden. The Cockcrofts had been in the textile industry for generations, and three of Cockcroft's brothers followed in the family business. In 1914, Cockcroft earned a scholarship to attend the University of Manchester. During World War I (1914-1918), he served from 1915 to 1918 in the Royal Field Artillery. After being discharged from the service, he returned to Manchester, switching his field of study from mathematics to electrical engineering. He was employed as a college apprentice at an electrical company while working toward his M.Sc. degree, which he received in 1922.
He then enrolled at St. John's College, Cambridge. In 1924, he was awarded a B.A. degree in mathematics. That year, he became a research assistant at Cambridge's Cavendish Laboratory, conducting research under the supervision of Sir Ernest Rutherford. At Cavendish, Cockcroft assisted Russian physicist Pyotr Kapitsa by engineering magnetic coils and other equipment for his experiments. In addition, Cockcroft taught physics and supervised the rewiring of the college. He was awarded a Ph.D. degree in 1928, the same year he began his collaboration with Walton, who, at the time, was director of the laboratory. By 1919, Rutherford had transmuted nitrogen to oxygen by smashing nitrogen atoms with naturally occurring alpha particles. Cockcroft and Walton worked on developing a technique to artificially accelerate particles at an even higher rate than the alpha particles. Using their accelerator, the two scientists bombarded lithium with hydrogen and formed helium. Initially, the experiment had created a release of energy, but it was so slight that Cockcroft did not see any practical application for it. In the late 1930's, however, German scientists bombarded uranium and learned the full potential of a nuclear reaction, which led to the development of nuclear power.
In 1935, Cockcroft was named director of the Royal Society's Mond Laboratory in Cambridge. Shortly before the onset of World War II (1939-1945), he was appointed Jacksonian Professor of Natural Philosophy at Cambridge. After the start of the war, he accepted a position with the Ministry of Supply. At the end of 1940, he became chief superintendent of the Air Defence Research and Development Establishment. During the war, Cockcroft oversaw development of shortwave radar, which played an important role in England's successful air defenses against Germany. Cockcroft left England for Montreal, Canada, in 1944, to oversee the atomic energy division of that country's National Research Council and the Chalk River Laboratory, where he headed a group whose efforts contributed to the Manhattan Project, a secret United States program to develop the atomic bomb.
When the war ended in 1945, he returned to England to serve as director of the Atomic Energy Research Establishment at Harwell. Cockcroft took a leading role in shaping England's nuclear power policy. He believed that nuclear energy could be a source of cheap electricity and saw that vision realized in the early 1950's, when construction began on the world's first nuclear power station at Calder Hall in northern England, in 1954, Cockcroft became a member of the newly created Atomic Energy Authority (AEA). Five years later, he became the first master of Churchill College of Cambridge University, while continuing to serve as a part-time member of the AEA.