John Cockcroft

Picture of John Cockcroft

Date of Birth: 05/27/1897

Age: 70

Citizenship: United Kingdom


In Manchester, K. began to study mathematics and physics attending lectures Ernest Rutherford. Rutherford received recognition for their work on radioactivity and atomic structure, was able to prove that alpha particles are the nuclei of helium atoms. Moreover, he showed that atoms consist of a positively charged nucleus surrounded by orbiting negatively charged electrons. It was a time when in front of mathematicians and physicists had to face several serious problems. Radioactivity was discovered by Henri Becquerel less than 20 years ago, in 1896 .; Albert Einstein theory of relativity, published in 1905, only started to be comprehended by scientists. But the outbreak of the First World War, and in 1915, after years of study at the university, K. joined volunteer units YMCA. His military service called in the same year. Prior to its release to the reserve in 1918, he fought on the Western Front, and moved by the service from the signalman to an officer of the Royal Field Artillery.

Back in Manchester, K. began to study electrical engineering, and for this work received a master`s degree in 1922, becoming later a scholarship in mathematics St. College. John Cambridge, where he received a bachelor`s degree with honors in 1924 and entered the Cavendish Laboratory in Cambridge junior assistant researcher. Four years later, he received his doctorate. Cambridge K. lectured in physics and studied mathematics and technical developments. Together with the Russian physicist Pyotr Kapitsa, he developed a transformer winding to produce intense magnetic fields. He also examined the surface of the film obtained by the atomic beam.

Rutherford was the director of the Cavendish Laboratory in 1919, came here the famous scientist, who proved that the nucleus can be destroyed by bombarding its subatomic particles. The splitting of the nucleus, Rutherford is performed using the natural radiation of alpha particles (helium nuclei) and turning at the same time the nitrogen atoms of oxygen atoms has opened up a new field of experimental research. Next the primary goal was to learn how to carry out the transmutation of atoms on a much larger scale than it could be done with the help of Rutherford`s methods. Some researchers believe that this could be achieved by accelerating atomic particles in large quantities. Since the positively charged particles experience a strong repulsion from the atomic nuclei, which are also positively charged, it takes an extremely large accelerations.

Many scientists in Europe and the United States sought to achieve more race particle acceleration using two different approaches. The so-called direct method of energy is obtained by using a single high-voltage electric pulse. In another method, the particles are accelerated, passing cyclically through the low-voltage field several times. Of the two methods of cyclic seemed most researchers more encouraging: although required more sophisticated equipment, but here it is used the available voltage, while the direct method requires a high voltage was difficult to get on the equipment of the time for it.

Inspired by the theories of physicist George Gamow Russian origin, K. decided to develop a direct method. Gamow using quantum mechanics has estimated that, since the subatomic particles have wave properties, they from time to time be able to penetrate the nuclear threshold, even when they do not have enough energy to overcome it. Equations Gamow explained how alpha particles can leave the nucleus of radioactive elements; but K. realized that the same principles allow other particles to penetrate into the core by using energy much smaller than previously thought.

With Ernest Walton, his colleague at the Cavendish Laboratory, K. developed based on the direct method of installation available to provide power only 600 kilovolts to a tube containing hydrogen. (To overcome nuclear barrier would require several million. Volts.) With this setting, K. Walton and in April 1932 bombarded the lithium hydrogen nuclei, or protons. "Almost immediately, - later recalled K., - at an energy of 125 kilovolts Dr. Walton saw nuclear scintillation characteristic of alpha particles." They turned the lithium and hydrogen into helium, thus becoming the first scientists, who managed to artificially split the atom. Their achievement has served as experimental confirmation of Gamow`s theory and found that the amount of energy released when atoms transformations, corresponds exactly to the basic equation of Einstein`s relativity theory: E = mc2.

In the 30-ies. K. continued his experiments, using different bombarding particles and atomic nuclei, such as boron and fluorine. After the discovery of artificial radioactive elements Frederic Joliot and Irene Joliot-Curie and K. Walton have shown that they can also receive items such irradiating the boron and carbon nuclei of hydrogen. In 1934, K., able administrator, was appointed director of the Royal Society Mond Laboratory in Cambridge. A year later he and Rutherford took up the refurbishment of the Cavendish Laboratory, in particular setting there cyclotron - accelerator, invented by Ernest O. Lawrence. Circular accelerators were soon improved and have now become generally accepted, although the generator Cockcroft - Walton continues to be used as a source of protons in a series of powerful settings.

In 1939, World War II began, and K. again took part in the military developments of the UK. For he had primary responsibility for the development and deployment of the radar, the decisive factor in the success of Britain in the air war against Germany. In 1940 he was sent to the US as Vice President Tizardovskoy Commission, which negotiated the exchange of technical military information to American scientists before the United States entered the war. After returning from the US Department K. led research RAF. In 1944 he went to Canada to head the Atomic Energy Department, subordinate to the National Research Council of Canada; this group took part in the Manhattan Project to develop and produce the first atomic bomb.

K. returned to England in 1946 to head the new agency for research in the field of nuclear energy, the result of the activities of which was to create the world`s first nuclear power station, Calder Hall in the north of England. Leading active in many areas, he was a member of the British Department for Atomic Energy and the CERN (European Center for Nuclear Research in Geneva, Switzerland). He founded what is now known as the Rutherford High Energy Laboratory, first-class equipment which is open for use by the entire scientific community of British universities.

K. Walton and shared in 1951 Nobel Prize in Physics "for his work on the transmutation of atomic nuclei by artificially accelerated atomic particles". In his speech, Ivar Waller of the Royal Swedish Academy of Sciences said: "The work of K. Walton and confirmed the validity of Einstein`s law on mass-energy equivalence. When lithium transmutation of energy is released as the total kinetic energy of the helium nuclei produced exceeds the energy of the original nuclei. According to Einstein`s law - continued Waller - is caused by the increase in energy of the corresponding mass loss of atomic nuclei. "

In 1959, he led by K. Churchill College, Cambridge. At his death in 1967, Karl was president of the Pugwash Conference, and was one of the leaders of the Liberal Party.

K. was married in 1925 to Eunice Elizabeth Crabtree, they had four daughters and a son.

In addition to the Nobel Prize, K. received the Royal Medal of the Royal Society (1954), an international gold medal Niels Bohr Danish Society of Civil Engineers, electricians and mechanics (1958), and the prize for `peaceful atom ", established by the Ford Foundation (1961 ).. He was a member of the Royal Society, and an honorary member of the American Academy of Arts and Sciences and the Royal Swedish Academy of Sciences. In 1948, K. was granted nobility. He holds honorary degrees from Oxford University, the University of London, University of Toronto and the University of Glasgow.