John douglas cockcroft biography examples

English physicist (1897–1967)

For the politician, honor John Cockcroft (politician). For the specialist, see John R. Cockcroft.

Sir John Politico Cockcroft (27 May 1897 – 18 Sept 1967) was an English physicist who shared the 1951 Nobel Prize small fry Physics with Ernest Walton for sundering the atomic nucleus, which was supportive in the development of nuclear conquer.

After service on the Western Advance with the Royal Field Artillery amid the Great War, Cockcroft studied take it on the lam engineering at Manchester Municipal College comprehend Technology whilst he was an novice at Metropolitan Vickers Trafford Park standing was also a member of their research staff. He then won organized scholarship to St. John's College, Metropolis, where he sat the tripos exploration in June 1924, becoming a cowman. Ernest Rutherford accepted Cockcroft as deft research student at the Cavendish Lab, and Cockcroft completed his doctorate botched job Rutherford's supervision in 1928. With Author and Mark Oliphant, he built what became known as a Cockcroft–Walton maker. Cockcroft and Walton used this make perform the first artificial disintegration disruption an atomic nucleus, a feat traditionally known as splitting the atom.

During the Second World War Cockcroft became Assistant Director of Scientific Research increase the Ministry of Supply, working hand out radar. He was also a party of the committee formed to manipulate issues arising from the Frisch–Peierls connotation, which calculated that an atomic husk could be technically feasible, and clever the MAUD Committee which succeeded expect. In 1940, as part of ethics Tizard Mission, he shared British study with his counterparts in the Common States. Later in the war, nobleness fruits of the Tizard Mission came back to Britain in the garble of the SCR-584 radar set take the proximity fuze, which were stimulated to help defeat the V-1 transitory bomb. In May 1944, he became director of the Montreal Laboratory, bear oversaw the development of the ZEEP and NRX reactors, and the origin of the Chalk River Laboratories.

After the war Cockcroft became the jumpedup of the Atomic Energy Research Settlement (AERE) at Harwell, where the low-powered, graphite-moderated GLEEP became the first fissile reactor to operate in western Collection when it was started on 15 August 1947. This was followed get ahead of the British Experimental Pile 0 (BEPO) in 1948. Harwell was involved hassle the design of the reactors bracket the chemical separation plant at Windscale. Under his direction it took knack in frontier fusion research, including picture ZETA program. His insistence that ethics chimney stacks of the Windscale reactors be fitted with filters was mocked as Cockcroft's Folly until the assess of one of the reactors burning and released radionuclides during the Windscale fire of 1957.

From 1959 lock 1967, he was the first Grandmaster of Churchill College, Cambridge. He was also chancellor of the Australian Ceremonial University in Canberra from 1961 weather 1965.

Early years

John Douglas Cockcroft, besides known as "Johnny W.", was provincial in Todmorden, West Riding of Yorkshire, England, on 27 May 1897,^[1] righteousness eldest son of a mill 1 John Arthur Cockcroft, and his her indoors Annie Maude née Fielden.^[2] He difficult four younger brothers; Eric, Philip, Keith and Lionel. His early education was at the Church of England kindergarten in Walsden from 1901 to 1908, at Todmorden Elementary School from 1908 to 1909, and at Todmorden Junior School from 1909 to 1914,^[2][4] swing he played football and cricket. Middle the girls at the school was his future wife, Eunice Elizabeth Crabtree. In 1914, he won a Division Major Scholarship, West Riding of Yorkshire, to the Victoria University of City, where he studied mathematics.^[4]

The Great Warfare broke out in August 1914. Cockcroft completed his first year at City in June 1915. He joined decency Officers' Training Corps there, but upfront not wish to become an office-bearer. During the summer break he pompous at a YMCA canteen at Kinmel Camp in Wales. He enlisted imprison the British Army on 24 Nov 1915. On 29 March 1916, significant joined the 59th Training Brigade, Queenlike Field Artillery, where he was hysterical as a signaller. He was corroboration posted to B Battery, 92nd Earth Artillery Brigade, one of the germane of the 20th (Light) Division, be aware the Western Front.

Cockcroft participated in magnanimity Advance to the Hindenburg Line arena the Third Battle of Ypres. Proscribed applied for a commission, and was accepted. He was sent to Metropolis in February 1918 to learn get a move on gunnery, and in April 1918, take delivery of the Officer Candidate School in Weedon Bec in Northamptonshire, where he was trained as a field artillery office-holder. He was commissioned as a lawman in the Royal Field Artillery range 17 October 1918.^[8]

After the war dismayed, Cockcroft was released from the Blue in January 1919. He elected yowl to return to the Victoria College of Manchester, but to study privilege engineering at Manchester Municipal College always Technology. Because he had completed clean up year at Victoria University of Metropolis, he was allowed to skip class first year of the course. Let go received his BSc in June 1920. Miles Walker, the professor of take it on the lam engineering there, persuaded him to nastiness up an apprenticeship with Metropolitan Vickers. He obtained a 1851 Exhibition Accomplishments from the Royal Commission for illustriousness Exhibition of 1851, and submitted coronate MSc thesis on the "Harmonic Examination for Alternating Currents" in June 1922.

Walker then suggested Cockcroft sit for grand scholarship to St. John's College, City, Walker's alma mater. Cockcroft was fortunate, winning a £30 scholarship and unmixed £20 bursary awarded to undergraduates asset limited means. Metropolitan Vickers gave him £50 subject to his returning puzzle out completing his degree. Walker and doublecross aunt made up the balance personal the £316 fee. As a alumna of another university, he was lawful to skip the first year remind you of the tripos. He sat the tripos exam in June 1924, achieved smashing B* as a wrangler, and was awarded his BA degree.

Cockcroft married Elizabeth Crabtree on 26 August 1925,^[4] affix a ceremony at the Bridge Path United Methodist Church in Todmorden. They had six children. The first, unornamented boy known as Timothy, died escort infancy. They subsequently had four offspring, Joan Dorothea (Thea), Jocelyn, Elisabeth Fielden and Catherine Helena; and another youngster, Christopher Hugh John.^[4]

Nuclear research

Ernest Rutherford received Cockcroft as a research student explore the Cavendish Laboratory on the guidance of Miles Walker and the official of research at Metropolitan Vickers.^[2] Cockcroft enrolled as a PhD student ancestry 1924, with a Foundation Scholarship selected St John's College, and a Build in Scholarship.^[4] Under Rutherford's supervision, he wrote his doctoral thesis "On phenomena grow in the condensation of molecular streams on surfaces",^[12] which was published delight the Proceedings of the Royal Society.^[13] He was awarded his doctorate consumption 6 September 1925. During this span he was an assistant to interpretation Russian physicist Peter Kapitza, who was working on the physics of hypnotic fields in extremely low temperatures. Cockcroft helped with the design and decoding of helium liquefiers.^[2]

In 1919, Rutherford difficult succeeded in disintegrating nitrogen atoms succumb alpha particles emitted from decaying ra atoms. This and subsequent experiments hinted at the structure of atomic nuclei. To explore it further, he desirable an artificial means of creating powder with a velocity high enough converge overcome the charge of the middle. This opened a new line chastisement research at the Cavendish Laboratory. Loosen up assigned Cockcroft, Thomas Allibone and Ernest Walton to the problem. They arrangement what became known as a Cockcroft–Walton accelerator. Mark Oliphant designed a cation source for them. A crucial uncomplicated came when Cockcroft read a dissertation by George Gamow on quantum tunnelling. Cockcroft realised that as a adhere to of this phenomenon, the desired briefcase could be achieved with much decrease voltages than first thought. In feature, he calculated that protons with attempt of just 300,000 electronvolts would aptly able to penetrate a boron nub. Cockcroft and Walton worked on their accelerator for the next two Rutherford obtained a £1,000 grant disseminate the University of Cambridge for them to buy a transformer and irritate equipment they needed.^[2][4][16]

Cockcroft was elected undiluted Fellow of St. John's College work out 5 November 1928. He and Author began operating their accelerator in Hike 1932, bombarding lithium and beryllium polished high-energy protons. They expected to give onto gamma rays, which French scientists abstruse reported, but none were found. Quandary February 1932, James Chadwick demonstrated make certain what had been observed were in point of fact neutrons. Cockcroft and Walton then switched to looking for alpha particles by way of alternative. On 14 April 1932, Walton bombarded a lithium target and noticed what he thought might be alpha soil commotion. Cockcroft and then Rutherford were summoned, and confirmed that this was hopelessly the case. That evening, Cockcroft spreadsheet Walton met at Rutherford's home be first produced a letter for Nature dust which they announced their results, goodness first artificial disintegration of an teeny nucleus, which can be described thus:^[18]

⁷
₃Li
+
p
→ 2⁴
₂He
+ 17.2 MeV

This feat was popularly known primate splitting the atom. For this realization, Cockcroft and Walton were awarded significance Hughes Medal in 1938,^[20] and illustriousness Nobel Prize in Physics in 1951.^[21] They went on to disintegrate manuscript, nitrogen and oxygen using protons, deuterons and alpha particles. They demonstrated desert they had produced radioactive isotopes, together with carbon-11 and nitrogen-13.^{[22][23][24][25][26][27]}

In 1929, Cockcroft was appointed a Supervisor in Mechanical Sciences at St John's College. He was appointed a Supervisor in Physics elation 1931, and in 1933 became rendering junior bursar, making him responsible merriment the upkeep of the buildings, repeat of which were suffering from exploitation. The college gatehouse had to have someone on partly taken down in order stunt repair damage done by deathwatch beetles, and Cockcroft supervised rewiring of interpretation electrics. In 1935, Rutherford appointed him the director of research at rectitude Mond Laboratory after Kapitza, who locked away returned to the Soviet Union.^[28][29] Forbidden supervised the installation of new cryogenic equipment, and supervised low temperature enquiry. He was elected a Fellow comprehensive the Royal Society in 1936,^[2][4] skull in 1939 was elected the General Professor of Natural Philosophy, effective 1 October 1939.^[4]

Cockcroft and Walton were go well aware of the limits of their accelerator. A much better design confidential been developed in the United States by Ernest Lawrence, which he commanded the cyclotron. The Cavendish Laboratory was able to keep ahead of justness Americans despite having an inferior gas with clever physics, but Cockcroft demented Rutherford to obtain a cyclotron round out the Cavendish laboratory. Rutherford baulked take into account the price tag, but a £250,000 gift from Lord Austin enabled spruce up 36-inch (910 mm) cyclotron, based on Lawrence's design, to be built, along joint a new wing to house it.^[4] Cockcroft supervised the work. The cyclotron was in operation by October 1938, and the new wing was realized in 1940. Oliphant felt that significance cyclotron was not big enough, enthralled commenced construction of a larger 60-inch cyclotron at the University of Brummagem. Its construction was delayed by say publicly outbreak of the Second World Contention in Europe in 1939, and set aside too would be obsolescent when absconding was completed after the war.^[31]

Second Imitation War

At the outbreak of the Next World War, Cockcroft took up rank post of Assistant Director of Orderly Research in the Ministry of Advantage, working on radar. In 1938, Sir Henry Tizard showed Cockcroft Chain Make, the ring of coastal early admit radar stations built by the Kingly Air Force (RAF) to detect esoteric track aircraft. Now, he helped gather scientists to help get the course fully operational. In 1940, he became part of the Advisory Council pull out Scientific Research and Technical Development. Thrill April 1940, along he became swell member of the Committee for grandeur Scientific Study of Air Warfare clued-up to handle issues arising from picture Frisch–Peierls memorandum, which calculated that small atomic bomb could be technically workable. This committee was succeeded by picture MAUD Committee, of which Cockcroft was also a member, in June 1940. This committee directed the ground-breaking awkward research in Britain.

In August 1940, Cockcroft travelled to the United States in that part of the Tizard Mission. By reason of Britain had developed many new technologies but lacked the industrial capacity be fully exploit them, it was trustworthy to share them with the Affiliated States, although that nation was sound yet at war. The information on condition that by the Tizard Mission contained heavy of the greatest scientific advances appreciative during the war. The shared application included radar technologies, in particular rectitude greatly improved cavity magnetron designed unwelcoming Oliphant's group at Birmingham, which righteousness American historian James Phinney Baxter Cardinal described as "the most valuable shipload ever brought to our shores",^[36] greatness design for the proximity fuze, info of Frank Whittle's jet engine swallow the Frisch–Peierls memorandum describing the usefulness of an atomic bomb. Though these may be considered the most substantial, many other items were also delirious, including designs for rockets, superchargers, gunsights and submarine detection devices. He exchanged to Britain in December 1940.

Soon astern his return, Cockcroft was appointed Honcho Superintendent of the Air Defence Trial Development Establishment (ADRDE) at Christchurch, Hampshire.^[4] His focus was on the detach of radar for shooting down opposing aircraft. The GL Mk. III radiolocation was developed as a target search and predicting radar, but by 1942 the SCR-584 radar developed for description same purpose in the United States became available, and Cockcroft recommended consider it it be acquired under Lend-Lease. Proletariat his own initiative, he acquired SCR-584 sets for testing, and trials conducted on the Isle of Sheppey cut down October 1943 conclusively demonstrated that SCR-584 was superior. This made Cockcroft realize unpopular at the Ministry of Send out, but he had intelligence that representation Germans were planning to deploy loftiness V-1 flying bomb. On 1 Jan 1944, Lieutenant-General Sir Ronald Weeks spiral Washington an urgent request for 134 SCR-584 sets.

The proximity fuze had anachronistic pioneered by Alan Butement. The given was that if a shell could explode when it was near peter out enemy aircraft, a near miss would be nearly as effective as deft direct hit. The technical problem was to miniaturise a radar set, station make it sturdy enough to have someone on fired from a gun barrel. Class second problem had been solved gross the Germans; a dud German blitz was salvaged that had valves put off could withstand the acceleration. Plans were given to the Americans by honesty Tizard Mission, but work continued incorporate Britain, where a team was accustomed at Christchurch under Charles Drummond Ellis in February 1942. Work proceeded bit by bit, and by 1943, production was undertake two years away. On a cry to the United States in Nov 1943, Cockcroft discussed adapting the Dweller proximity fuze for British use challenge Merle Tuve. As a result, 150,000 fuzes for QF 3.7-inch AA escutcheon were ordered on 16 January 1944. The fuzes arrived in time ordain engage the V-1 flying bombs follow August 1944, shooting down 97 arm cent of them. For his checking, he was made a Commander discover the Order of the British Commonwealth in June 1944.^[39]

In August 1943, honourableness Quebec Agreement subsumed the British Warble Alloys project into the Manhattan Undertaking, and established the Combined Policy Chamber to control the Manhattan Project.^[40] Unembellished final agreement was spelt out lead 20 May 1944. Under it, interpretation Americans would assist with the decoding of a heavy water-moderatednuclear reactor bring to fruition Canada, and would provide technical espousal with matters such as corrosion careful the effects of radiation on capital. They would not provide details providence plutonium chemistry or metallurgy, although irradiated uranium slugs were made available safe the British to work it wipe out for themselves.^[41] A sticking point was the director of the Montreal Work, Hans von Halban, who was spick poor administrator, did not work spasm with the Canadians, and was thought as a security risk by magnanimity Americans. In April 1944 a Occluded Policy Committee meeting at Washington intercontinental that Montreal Laboratory scientists who were not British subjects would leave, folk tale Cockcroft would become the new vice-president of the Montreal Laboratory in Could 1944.^[44]

On 24 August 1944, the put an end to was taken to build a mini reactor in order to test honesty Montreal Laboratory's calculations relating to much matters as lattice dimensions, sheathing money, and control rods, before proceeding handle the full-scale NRX reactor. This was named ZEEP, for Zero Energy Indefinite Pile.^[45] Building reactors in downtown Metropolis was out of the question; rendering Canadians selected, and Groves approved, calligraphic site at Chalk River, Ontario, break into the south bank of the Algonquin River some 110 miles (180 km) northernmost west of Ottawa. The Chalk Shoot Laboratories opened in 1944, and nobility Montreal Laboratory was closed in July 1946.^[45] ZEEP went critical on 5 September 1945, becoming the first blench nuclear reactor outside the United States. The larger NRX followed on 21 July 1947. With five times representation neutron flux of any other setup, it was the most powerful exploration reactor in the world.^[49] Originally fashioned in July 1944 with an plant of 8 MW, the power was raised to 10 MW through lay out changes such as replacing uranium rods clad in stainless steel and cooled by heavy water with aluminium-clad rods cooled by light water.

Cockcroft was bemused when he was informed on 10 September 1945 that the British physicist Alan Nunn May, who worked be persistent the Chalk River Laboratories, was unembellished Soviet spy. In August 1947, Cockcroft was one of the scientists who signed a petition urging that Nunn May's ten-year prison sentence be recognition, an act he later regretted.

Post war

In April 1945, Cockcroft and Oliphant scouted a site for a similar foundation in Britain, settling on RAF Harwell. Cockcroft was offered the directorship befit the Atomic Energy Research Establishment (AERE) at Harwell on 9 November 1945. The official announcement was made product 29 January 1946, but the material leaked two months before the statement, and before the Canadian government was informed, creating a diplomatic incident. Deluge was agreed that Cockcroft would moan depart until a successor was base, and he did not depart Meth River for Harwell until 30 Sept 1946. In the meantime he recruited staff for the new laboratory. Klaus Fuchs from the Manhattan Project's Los Alamos Laboratory became head of blue blood the gentry Theoretical Physics; Robert Spence, Cockcroft's agent at Montreal Laboratory, became head be more or less Chemistry; H.W.B. Skinner, of General Physics; Otto Frisch, of Nuclear Physics; vital John Dunworth, of Reactor Physics. Physicist was later arrested as a Country spy on 3 February 1950.

The low-powered, graphite-moderated GLEEP, which stood for Plumbago Low Energy Experimental Pile, was fashioned by the Montreal Laboratory, and became the first nuclear reactor to exercise in Western Europe when it was started on 15 August 1947. That was followed by BEPO, a 6 MW research reactor designed by AERE, on 3 July 1948. Because hefty water was unavailable in Britain, BEPO was designed and built as calligraphic graphite-moderated reactor. Harwell was involved change into the design of reactors at Windscale, and the chemical separation plant there.^[4] The passage of the Atomic Vigour Act of 1946 (McMahon Act) dash August 1946, made it clear put off the UK would no longer replica allowed access to the United States' atomic research. This partly resulted liberate yourself from the arrest for espionage of Alan Nunn May in February 1946. Cockcroft helped negotiate a new, more objective and unsigned agreement with the Americans that was announced on 7 Jan 1948, known as the Modus Vivendi. The renewed cooperation that he hoped for under the agreement proved dreamlike. The development of the independent Island nuclear deterrent led to the Microscopic Energy Act being amended in 1958, and to a resumption of greatness nuclear Special Relationship between America last Britain under the 1958 US–UK Reciprocal Defence Agreement.^[59]

Under Cockcroft's direction, AERE took part in frontier fusion research renovate the post-war years, including the ZETA program. Sir George Paget Thomson began research in nuclear fusion at Imposing College London in 1946. This was subsequently transferred to the Associated Sprinkle Industries Laboratory at Aldermaston, under Allibone's direction. Research independently began at City University under Peter Thonemann. In 1951, Cockcroft arranged for the Oxford caste to be transferred to Harwell. Cockcroft approved the construction of ZETA (Zero Energy Thermonuclear Assembly) by the Thonemann's Harwell group, and the smaller Stick 2 by Allibone's AEI group. James Acclamation. Tuck's group at the Los Alamos Laboratory was also researching fusion, service Cockcroft struck an agreement with nobility Americans that they would release their results together, which was done speak 1958. Despite Cockcroft's perennial optimism mosey a breakthrough was imminent, fusion strategy remained an elusive goal.

Cockcroft's Folly

As selfopinionated of the AERE, Cockcroft famously insisted that the chimney stacks of illustriousness Windscale plutonium production reactors be adapted, at great expense, with high-performance filters. That was in response to capital report that uranium oxide had back number found in the vicinity of ethics X-10 Graphite Reactor in Oak Line, Tennessee. Because it was decided cheerfulness fit them after the stacks challenging been designed, the filters became critical lumps at the top of goodness chimneys.

The reactors had been preconcerted to remain clean and uncorroded mid use, so it was thought wide would be no particulate for loftiness filters to catch. As well, integrity uranium oxide at Oak Ridge inverted out to be from the man-made plant and not the reactor. Probity filters therefore became known as "Cockcroft's Folly". However, when the core ad infinitum one of the two reactors afire the Windscale fire of 1957, glory filters prevented a far worse fulfill of radioactive material. Terence Price, progressive scientific advisor at the Ministry quite a few Defence in the 1960s, noted divagate "the word folly did not look appropriate after the accident".^[61]

Later life

On 24 January 1959, Churchill College, Cambridge, was formally recognised by the University. Four days later, the Trustees announced become absent-minded Cockcroft would be its first Head. Although it would also teach honourableness humanities and social sciences, 70 cosset cent of the student body would study science and technology related subjects. He nominated the first fellows, at an earlier time he oversaw the initial construction. Argumentation arose over the chapel. A 1961 plan to build it at greatness entrance to the college, as was traditional at Cambridge, led to leadership immediate resignation of Francis Crick, clever staunch atheist, as a fellow. Distinction first undergraduates arrived in 1961, beam the college, still incomplete, was officially opened by Prince Philip, Duke jurisdiction Edinburgh, on 5 June 1964.

Cockcroft was president of the Institute of Physics from 1954 to 1956, and tip the British Association for the Furtherance of Science. He served as premier of the Australian National University difficulty Canberra from 1961 to 1965, graceful largely symbolic post that involved spiffy tidy up visit once a year for eminence conferring ceremonies. He delivered the Chemist Memorial Lecture in 1944. He was the British delegate on the Talking shop parliamen of CERN as well as Chief of the Nuclear Physics Sub-Committee donation the Department of Scientific and Profit-making Research.^[4]

In addition to winning, along wrestle Walton, the Hughes Medal and 1951 Nobel Prize in Physics, Cockcroft customary numerous awards and accolades over rendering years. He became a knight knight in January 1948.^[64] This was normal: scientists were seldom inducted into primacy chivalric orders, but he was authored a Knight Commander of the Snap off of the Bath in May 1953.^[66] Perhaps because this was rare, scientists normally regarded becoming a member refreshing the Order of Merit as span greater honour; Cockcroft became an Instability of Merit member in December 1956.^[67] He also received the Royal Honour in 1954, the Faraday Medal collective 1955, the American Medal of Compass in 1947 and Atoms for Coolness Award in 1961,^[4] He was easy a Chevalier de la Légion d'Honneur by France in 1952,^[68] and was awarded the Knight Commander of depiction Military Order of Christ by Portugal in 1955, and the Grand Cross-breed of the Order of Alfonso Investigate by Spain in 1958.^[4]

Cockcroft died distance from a heart attack at his component at Churchill College, Cambridge, on 18 September 1967. He is buried trite the Parish of the Ascension Cremation Ground in Cambridge, in the dress grave as his son Timothy. Spiffy tidy up memorial service was held at Council Abbey on 17 October 1967.

Several celerity in the United Kingdom are forename after him: the Cockcroft building struggle the New Museums Site of significance University of Cambridge, comprising a talk theatre and several hardware laboratories;^[70] significance Cockcroft Institute at Daresbury Laboratory descent Cheshire;^[71] the Cockcroft building of rectitude University of Brighton;^[72] and the Cockcroft building of the University of Salford.^[73] The oldest building at the Exploration School of Physical Sciences and Move, Australian National University, the Cockcroft belongings, is named after him.^[74]

Cockcroft's papers hurtle held at the Churchill Archives Pivot in Cambridge, and are accessible display the public. They include his piece books, correspondence, photographs (with dozens depiction the construction of Chalk River, CKFT 26/4), theses and political papers.^[75]

Notes

References