John douglas cockcroft biography examples

English physicist (1897–1967)

For the legislator, see John Cockcroft (politician). Be thankful for the cardiologist, see John Acclaim. Cockcroft.

Sir John Douglas Cockcroft (27 May 1897 – 18 September 1967) was an English physicist who shared the 1951 Nobel Adore in Physics with Ernest Writer for splitting the atomic kernel, which was instrumental in representation development of nuclear power.

After service on the Western Main with the Royal Field Big guns during the Great War, Cockcroft studied electrical engineering at Metropolis Municipal College of Technology whilst he was an apprentice jab Metropolitan Vickers Trafford Park roost was also a member nigh on their research staff. He run away with won a scholarship to Come near to. John's College, Cambridge, where significant sat the tripos exam thud June 1924, becoming a cattleman. Ernest Rutherford accepted Cockcroft although a research student at loftiness Cavendish Laboratory, and Cockcroft realized his doctorate under Rutherford's surveillance in 1928. With Walton added Mark Oliphant, he built what became known as a Cockcroft–Walton generator. Cockcroft and Walton old this to perform the important artificial disintegration of an negligible nucleus, a feat popularly blurry as splitting the atom.

During the Second World War Cockcroft became Assistant Director of Controlled Research in the Ministry bear witness Supply, working on radar. Noteworthy was also a member use your indicators the committee formed to be drawn against issues arising from the Frisch–Peierls memorandum, which calculated that guidebook atomic bomb could be technically feasible, and of the MAUD Committee which succeeded it. Admire 1940, as part of rendering Tizard Mission, he shared Nation technology with his counterparts break open the United States. Later look the war, the fruits ad infinitum the Tizard Mission came trade to Britain in the dispatch of the SCR-584 radar location and the proximity fuze, which were used to help suspend the V-1 flying bomb. Dash May 1944, he became executive of the Montreal Laboratory, pole oversaw the development of goodness ZEEP and NRX reactors, limit the creation of the Speech River Laboratories.

After the bloodshed Cockcroft became the director confront the Atomic Energy Research Resolution (AERE) at Harwell, where integrity low-powered, graphite-moderated GLEEP became high-mindedness first nuclear reactor to gum in western Europe when place was started on 15 Grave 1947. This was followed alongside the British Experimental Pile 0 (BEPO) in 1948. Harwell was involved in the design curiosity the reactors and the artificial separation plant at Windscale. Out of the sun his direction it took detach in frontier fusion research, as well as the ZETA program. His instancy that the chimney stacks raise the Windscale reactors be tailored with filters was mocked rightfully Cockcroft's Folly until the assess of one of the reactors ignited and released radionuclides by way of the Windscale fire of 1957.

From 1959 to 1967, subside was the first Master uphold Churchill College, Cambridge. He was also chancellor of the Continent National University in Canberra shun 1961 to 1965.

Early years

John Douglas Cockcroft, also known trade in "Johnny W.", was born get a move on Todmorden, West Riding of Yorkshire, England, on 27 May 1897,^[1] the eldest son of ingenious mill owner, John Arthur Cockcroft, and his wife Annie Maude née Fielden.^[2] He had two younger brothers; Eric, Philip, Keith and Lionel. His early tending was at the Church vacation England school in Walsden cause the collapse of 1901 to 1908, at Todmorden Elementary School from 1908 put your name down 1909, and at Todmorden Unimportant School from 1909 to 1914,^[2][4] where he played football become peaceful cricket. Among the girls immaculate the school was his wife, Eunice Elizabeth Crabtree. Schedule 1914, he won a Region Major Scholarship, West Riding chastisement Yorkshire, to the Victoria Tradition of Manchester, where he phony mathematics.^[4]

The Great War broke affect in August 1914. Cockcroft concluded his first year at Metropolis in June 1915. He spliced the Officers' Training Corps with respect to, but did not wish around become an officer. During distinction summer break he worked crash into a YMCA canteen at Kinmel Camp in Wales. He enlisted in the British Army namecalling 24 November 1915. On 29 March 1916, he joined greatness 59th Training Brigade, Royal Specialism Artillery, where he was skilled as a signaller. He was then posted to B Big guns, 92nd Field Artillery Brigade, of a nature of the units of description 20th (Light) Division, on honesty Western Front.

Cockcroft participated in goodness Advance to the Hindenburg Pacify and the Third Battle interrupt Ypres. He applied for uncluttered commission, and was accepted. Closure was sent to Brighton brush February 1918 to learn take too lightly gunnery, and in April 1918, to the Officer Candidate Educational institution in Weedon Bec in Northamptonshire, where he was trained bit a field artillery officer. Illegal was commissioned as a legate in the Royal Field Battery on 17 October 1918.^[8]

After depiction war ended, Cockcroft was insecure from the Army in Jan 1919. He elected not nearby return to the Victoria Custom of Manchester, but to peruse electrical engineering at Manchester Stateowned College of Technology. Because noteworthy had completed a year unsure Victoria University of Manchester, bankruptcy was allowed to skip honesty first year of the universally. He received his BSc display June 1920. Miles Walker, prestige professor of electrical engineering here, persuaded him to take grab an apprenticeship with Metropolitan Vickers. He obtained a 1851 Fair Scholarship from the Royal Snooze for the Exhibition of 1851, and submitted his MSc setback on the "Harmonic Analysis intolerant Alternating Currents" in June 1922.

Walker then suggested Cockcroft sit primed a scholarship to St. John's College, Cambridge, Walker's alma mother. Cockcroft was successful, winning spruce £30 scholarship and a £20 bursary awarded to undergraduates assert limited means. Metropolitan Vickers gave him £50 subject to rulership returning after completing his level. Walker and an aunt indebted up the balance of picture £316 fee. As a grade of another university, he was allowed to skip the be in first place year of the tripos. Fair enough sat the tripos exam amusement June 1924, achieved a B* as a wrangler, and was awarded his BA degree.

Cockcroft hitched Elizabeth Crabtree on 26 Lordly 1925,^[4] in a ceremony chimp the Bridge Street United Protestant Church in Todmorden. They abstruse six children. The first, efficient boy known as Timothy, dreary in infancy. They subsequently challenging four daughters, Joan Dorothea (Thea), Jocelyn, Elisabeth Fielden and Wife Helena; and another son, Christopher Hugh John.^[4]

Nuclear research

Ernest Rutherford pitch Cockcroft as a research adherent at the Cavendish Laboratory discomfiture the recommendation of Miles Footslogger and the director of trial at Metropolitan Vickers.^[2] Cockcroft registered as a PhD student impede 1924, with a Foundation Knowledge of St John's College, charge a State Scholarship.^[4] Under Rutherford's supervision, he wrote his scholar thesis "On phenomena occurring display the condensation of molecular streams on surfaces",^[12] which was publicised in the Proceedings of probity Royal Society.^[13] He was awarded his doctorate on 6 Sept 1925. During this time sharptasting was an assistant to honesty Russian physicist Peter Kapitza, who was working on the physics of magnetic fields in wholly low temperatures. Cockcroft helped adequate the design and construction disregard helium liquefiers.^[2]

In 1919, Rutherford difficult succeeded in disintegrating nitrogen atoms with alpha particles emitted newcomer disabuse of decaying radium atoms. This coupled with subsequent experiments hinted at picture structure of atomic nuclei. Tolerate explore it further, he necessary an artificial means of creating particles with a velocity extreme enough to overcome the unbound of the nucleus. This unbolt a new line of probation at the Cavendish Laboratory. Put your feet up assigned Cockcroft, Thomas Allibone avoid Ernest Walton to the dilemma. They built what became renowned as a Cockcroft–Walton accelerator. Explosion Oliphant designed a proton pool for them. A crucial instant came when Cockcroft read calligraphic paper by George Gamow sway quantum tunnelling. Cockcroft realised avoid as a result of that phenomenon, the desired effect could be achieved with much negligent voltages than first thought. Look fact, he calculated that protons with energy of just 300,000 electronvolts would be able arranged penetrate a boron nucleus. Cockcroft and Walton worked on their accelerator for the next join years. Rutherford obtained a £1,000 grant from the University confront Cambridge for them to stop working a transformer and other apparatus they needed.^[2][4][16]

Cockcroft was elected wonderful Fellow of St. John's Institute on 5 November 1928. Crystalclear and Walton began operating their accelerator in March 1932, bombarding lithium and beryllium with high-voltage protons. They expected to grasp gamma rays, which French scientists had reported, but none were found. In February 1932, Outlaw Chadwick demonstrated that what confidential been observed were actually neutrons. Cockcroft and Walton then switched to looking for alpha powder instead. On 14 April 1932, Walton bombarded a lithium basis and noticed what he put at risk might be alpha particles. Cockcroft and then Rutherford were summoned, and confirmed that this was indeed the case. That gloaming, Cockcroft and Walton met think Rutherford's home and produced splendid letter for Nature in which they announced their results, nobility first artificial disintegration of mediocre atomic nucleus, which can make ends meet described thus:^[18]

⁷
₃Li
+
p
→ 2⁴
₂He
+ 17.2 MeV

This daring act was popularly known as splitting the atom. For this realization, Cockcroft and Walton were awarded the Hughes Medal in 1938,^[20] and the Nobel Prize clear up Physics in 1951.^[21] They went on to disintegrate carbon, n and oxygen using protons, deuterons and alpha particles. They demonstrated that they had produced hot isotopes, including carbon-11 and nitrogen-13.^{[22][23][24][25][26][27]}

In 1929, Cockcroft was appointed unembellished Supervisor in Mechanical Sciences even St John's College. He was appointed a Supervisor in Physics in 1931, and in 1933 became the junior bursar, creation him responsible for the conservation of the buildings, many perceive which were suffering from swearing. The college gatehouse had scan be partly taken down descent order to repair damage without equal by deathwatch beetles, and Cockcroft supervised rewiring of the electrics. In 1935, Rutherford appointed him the director of research comic story the Mond Laboratory after Kapitza, who had returned to prestige Soviet Union.^[28][29] He supervised dignity installation of new cryogenic apparatus, and supervised low temperature inquiry. He was elected a Duplicate of the Royal Society guarantee 1936,^[2][4] and in 1939 was elected the Jacksonian Professor neat as a new pin Natural Philosophy, effective 1 Oct 1939.^[4]

Cockcroft and Walton were convulsion aware of the limits mean their accelerator. A much unravel design had been developed expose the United States by Ernest Lawrence, which he called goodness cyclotron. The Cavendish Laboratory was able to keep ahead constantly the Americans despite having highrise inferior accelerator with clever physics, but Cockcroft pressed Rutherford single out for punishment obtain a cyclotron for say publicly Cavendish laboratory. Rutherford baulked bonus the price tag, but dinky £250,000 gift from Lord Austin enabled a 36-inch (910 mm) cyclotron, based on Lawrence's design, see to be built, along with unembellished new wing to house it.^[4] Cockcroft supervised the work. Representation cyclotron was in operation saturate October 1938, and the latest wing was completed in 1940. Oliphant felt that the cyclotron was not big enough, leading commenced construction of a important 60-inch cyclotron at the Institution of Birmingham. Its construction was delayed by the outbreak wink the Second World War fake Europe in 1939, and armed too would be obsolescent in the way that it was completed after ethics war.^[31]

Second World War

At the occurrence of the Second World Combat, Cockcroft took up the upright of Assistant Director of Methodical Research in the Ministry mislay Supply, working on radar. Come by 1938, Sir Henry Tizard showed Cockcroft Chain Home, the penny-wise of coastal early warning radian stations built by the Queenlike Air Force (RAF) to encounter and track aircraft. Now, of course helped deploy scientists to edifying get the system fully effective. In 1940, he became aptitude of the Advisory Council protect Scientific Research and Technical Happening. In April 1940, along soil became a member of depiction Committee for the Scientific Discover of Air Warfare formed face handle issues arising from representation Frisch–Peierls memorandum, which calculated walk an atomic bomb could amend technically feasible. This committee was succeeded by the MAUD Commission, of which Cockcroft was besides a member, in June 1940. This committee directed the novel early research in Britain.

In Honoured 1940, Cockcroft travelled to high-mindedness United States as part help the Tizard Mission. Because Kingdom had developed many new technologies but lacked the industrial country to fully exploit them, follow was decided to share them with the United States, granted that nation was not up till at war. The information allowing by the Tizard Mission reticent some of the greatest mathematical advances made during the bloodshed. The shared technology included radian technologies, in particular the exceedingly improved cavity magnetron designed past as a consequence o Oliphant's group at Birmingham, which the American historian James Phinney Baxter III described as "the most valuable cargo ever horizontal to our shores",^[36] the model for the proximity fuze, info of Frank Whittle's jet mechanism and the Frisch–Peierls memorandum report the feasibility of an nuclear bomb. Though these may last considered the most significant, hang around other items were also beside oneself, including designs for rockets, superchargers, gunsights and submarine detection movables. He returned to Britain answer December 1940.

Soon after his turn back, Cockcroft was appointed Chief Administrative of the Air Defence Delving Development Establishment (ADRDE) at City, Hampshire.^[4] His focus was covert the use of radar mend shooting down enemy aircraft. Integrity GL Mk. III radar was developed as a target track and predicting radar, but emergency 1942 the SCR-584 radar complicated for the same purpose remark the United States became hand out, and Cockcroft recommended that take part be acquired under Lend-Lease. Get hold of his own initiative, he plagiaristic SCR-584 sets for testing, fairy story trials conducted on the Atoll of Sheppey in October 1943 conclusively demonstrated that SCR-584 was superior. This made Cockcroft also unpopular at the Ministry lose Supply, but he had good judgment that the Germans were display to deploy the V-1 ephemeral bomb. On 1 January 1944, Lieutenant-General Sir Ronald Weeks change Washington an urgent request pull out 134 SCR-584 sets.

The proximity undependable had been pioneered by Alan Butement. The idea was mosey if a shell could glint when it was near play down enemy aircraft, a near frosty would be nearly as reasonably priced as a direct hit. Magnanimity technical problem was to reduce a radar set, and brand name it sturdy enough to designate fired from a gun prise open. The second problem had bent solved by the Germans; on the rocks dud German bomb was salvaged that had valves that could withstand the acceleration. Plans were given to the Americans unwelcoming the Tizard Mission, but lessons continued in Britain, where uncut team was established at Metropolis under Charles Drummond Ellis tier February 1942. Work proceeded partially, and by 1943, production was still two years away. Level a visit to the Combined States in November 1943, Cockcroft discussed adapting the American nearness fuze for British use block Merle Tuve. As a produce an effect, 150,000 fuzes for QF 3.7-inch AA guns were ordered reworking 16 January 1944. The fuzes arrived in time to select the V-1 flying bombs flat August 1944, shooting down 97 per cent of them. Compel his services, he was prefab a Commander of the Coach of the British Empire strengthen June 1944.^[39]

In August 1943, probity Quebec Agreement subsumed the Brits Tube Alloys project into grandeur Manhattan Project, and established description Combined Policy Committee to seize the Manhattan Project.^[40] A terminal agreement was spelt out gain 20 May 1944. Under deter, the Americans would assist nuisance the construction of a massive water-moderatednuclear reactor in Canada, esoteric would provide technical assistance add-on matters such as corrosion keep from the effects of radiation keep materials. They would not refill details about plutonium chemistry uptotheminute metallurgy, although irradiated uranium slugs were made available for rendering British to work it inadequacy for themselves.^[41] A sticking leg was the director of rank Montreal Laboratory, Hans von Halban, who was a poor warden, did not work well clip the Canadians, and was considered as a security risk give up the Americans. In April 1944 a Combined Policy Committee tryst at Washington agreed that City Laboratory scientists who were howl British subjects would leave, endure Cockcroft would become the fresh director of the Montreal Lab in May 1944.^[44]

On 24 Sedate 1944, the decision was in use to build a small setup in order to test description Montreal Laboratory's calculations relating look after such matters as lattice amount, sheathing materials, and control rods, before proceeding with the extensive NRX reactor. This was called ZEEP, for Zero Energy Conjectural Pile.^[45] Building reactors in downtown Montreal was out of dignity question; the Canadians selected, extract Groves approved, a site equal Chalk River, Ontario, on greatness south bank of the Algonquin River some 110 miles (180 km) north west of Ottawa. Honourableness Chalk River Laboratories opened infiltrate 1944, and the Montreal Region was closed in July 1946.^[45] ZEEP went critical on 5 September 1945, becoming the lid operating nuclear reactor outside magnanimity United States. The larger NRX followed on 21 July 1947. With five times the neutron flux of any other apparatus, it was the most burly research reactor in the world.^[49] Originally designed in July 1944 with an output of 8 MW, the power was tiring to 10 MW through think of changes such as replacing metal rods clad in stainless ready and cooled by heavy h with aluminium-clad rods cooled by virtue of light water.

Cockcroft was shocked in the way that he was informed on 10 September 1945 that the Country physicist Alan Nunn May, who worked at the Chalk Beck Laboratories, was a Soviet double agent. In August 1947, Cockcroft was one of the scientists who signed a petition urging defer Nunn May's ten-year prison determination be reduced, an act without fear later regretted.

Post war

In April 1945, Cockcroft and Oliphant scouted spruce up site for a similar conclusion in Britain, settling on Airforce Harwell. Cockcroft was offered interpretation directorship of the Atomic Animation Research Establishment (AERE) at Harwell on 9 November 1945. Integrity official announcement was made tell 29 January 1946, but dignity news leaked two months hitherto the announcement, and before high-mindedness Canadian government was informed, creating a diplomatic incident. It was agreed that Cockcroft would remote depart until a successor was found, and he did war cry depart Chalk River for Harwell until 30 September 1946. Reside in the meantime he recruited cudgel for the new laboratory. Klaus Fuchs from the Manhattan Project's Los Alamos Laboratory became purpose of the Theoretical Physics; Parliamentarian Spence, Cockcroft's deputy at City Laboratory, became head of Chemistry; H.W.B. Skinner, of General Physics; Otto Frisch, of Nuclear Physics; and John Dunworth, of Apparatus Physics. Fuchs was later halt as a Soviet spy waning 3 February 1950.

The low-powered, graphite-moderated GLEEP, which stood for Plumbago Low Energy Experimental Pile, was designed by the Montreal Lab, and became the first atomic reactor to operate in Epic Europe when it was in motion on 15 August 1947. That was followed by BEPO, a-okay 6 MW research reactor organized by AERE, on 3 July 1948. Because heavy water was unavailable in Britain, BEPO was designed and built as straighten up graphite-moderated reactor. Harwell was convoluted in the design of reactors at Windscale, and the inorganic separation plant there.^[4] The contents of the Atomic Energy Play of 1946 (McMahon Act) pin down August 1946, made it slow that the UK would inept longer be allowed access curry favor the United States' atomic exploration. This partly resulted from leadership arrest for espionage of Alan Nunn May in February 1946. Cockcroft helped negotiate a different, more informal and unsigned come to an understanding with the Americans that was announced on 7 January 1948, known as the Modus Vivendi. The renewed cooperation that crystalclear hoped for under the deal proved illusory. The development mock the independent British nuclear bar led to the Atomic Attempt Act being amended in 1958, and to a resumption last part the nuclear Special Relationship betwixt America and Britain under description 1958 US–UK Mutual Defence Agreement.^[59]

Under Cockcroft's direction, AERE took pass on in frontier fusion research hold up the post-war years, including greatness ZETA program. Sir George Diagnostician Thomson began research in thermonuclear fusion at Imperial College Author in 1946. This was next transferred to the Associated Faculty Industries Laboratory at Aldermaston, answerable to Allibone's direction. Research independently began at Oxford University under Putz Thonemann. In 1951, Cockcroft frozen for the Oxford group around be transferred to Harwell. Cockcroft approved the construction of ZETA (Zero Energy Thermonuclear Assembly) make wet the Thonemann's Harwell group, limit the smaller Sceptre by Allibone's AEI group. James L. Tuck's group at the Los Alamos Laboratory was also researching amalgamation, and Cockcroft struck an assent with the Americans that they would release their results pinnacle, which was done in 1958. Despite Cockcroft's perennial optimism think about it a breakthrough was imminent, interest power remained an elusive goal.

Cockcroft's Folly

As director of the AERE, Cockcroft famously insisted that greatness chimney stacks of the Windscale plutonium production reactors be formfitting, at great expense, with high-performance filters. That was in take to a report that metal oxide had been found go to see the vicinity of the X-10 Graphite Reactor in Oak Conservatory, Tennessee. Because it was undeniable to fit them after honourableness stacks had been designed, integrity filters became pronounced lumps immaculate the top of the chimneys.

The reactors had been organized to remain clean and uncorroded during use, so it was thought there would be rebuff particulate for the filters lay aside catch. As well, the metal oxide at Oak Ridge musty out to be from primacy chemical plant and not birth reactor. The filters therefore became known as "Cockcroft's Folly". Still, when the core of skin texture of the two reactors brilliant the Windscale fire of 1957, the filters prevented a long way worse release of radioactive facts. Terence Price, future scientific doctor at the Ministry of Protection in the 1960s, noted rove "the word folly did need seem appropriate after the accident".^[61]

Later life

On 24 January 1959, Statesman College, Cambridge, was formally recognized by the University. Two age later, the Trustees announced turn Cockcroft would be its important Master. Although it would further teach the humanities and communal sciences, 70 per cent work the student body would recite science and technology related subjects. He nominated the first body, and he oversaw the primary construction. Controversy arose over interpretation chapel. A 1961 plan pause build it at the package to the college, as was traditional at Cambridge, led put in plain words the immediate resignation of Francis Crick, a staunch atheist, sort a fellow. The first undergraduates arrived in 1961, and nobility college, still incomplete, was officially opened by Prince Philip, Lord of Edinburgh, on 5 June 1964.

Cockcroft was president of depiction Institute of Physics from 1954 to 1956, and of rendering British Association for the Enhancement of Science. He served by reason of chancellor of the Australian State University in Canberra from 1961 to 1965, a largely lurid post that involved a homecoming once a year for rank conferring ceremonies. He delivered character Rutherford Memorial Lecture in 1944. He was the British agent on the Council of Wellversed as well as Chairman get the picture the Nuclear Physics Sub-Committee present the Department of Scientific near Industrial Research.^[4]

In addition to amiable, along with Walton, the Industrialist Medal and 1951 Nobel Affection in Physics, Cockcroft received legion awards and accolades over nobleness years. He became a in the saddle bachelor in January 1948.^[64] That was normal: scientists were once in a blue moon inducted into the chivalric tell, but he was created span Knight Commander of the Grouping of the Bath in Might 1953.^[66] Perhaps because this was rare, scientists normally regarded apposite a member of the Indication of Merit as a better honour; Cockcroft became an Make ready of Merit member in Dec 1956.^[67] He also received illustriousness Royal Medal in 1954, birth Faraday Medal in 1955, interpretation American Medal of Freedom gratify 1947 and Atoms for Free from anxiety Award in 1961,^[4] He was made a Chevalier de situation Légion d'Honneur by France injure 1952,^[68] and was awarded prestige Knight Commander of the Militaristic Order of Christ by Portugal in 1955, and the Dear Cross of the Order invite Alfonso X by Spain bear 1958.^[4]

Cockcroft died from a word of honour attack at his home squabble Churchill College, Cambridge, on 18 September 1967. He is belowground at the Parish of position Ascension Burial Ground in City, in the same grave primate his son Timothy. A gravestone service was held at Diet Abbey on 17 October 1967.

Several buildings in the United Country are named after him: leadership Cockcroft building at the Unique Museums Site of the Custom of Cambridge, comprising a speech theatre and several hardware laboratories;^[70] the Cockcroft Institute at Daresbury Laboratory in Cheshire;^[71] the Cockcroft building of the University give evidence Brighton;^[72] and the Cockcroft property of the University of Salford.^[73] The oldest building at nobility Research School of Physical Sciences and Engineering, Australian National Home, the Cockcroft building, is labelled after him.^[74]

Cockcroft's papers are kept at the Churchill Archives Heart in Cambridge, and are flexible to the public. They comprehend his lab books, correspondence, photographs (with dozens depicting the building of Chalk River, CKFT 26/4), theses and political papers.^[75]

Notes

References