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Sir John Douglas Cockcroft, (27 May 1897 – 18 September 1967) was a British
physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate cau ...
who shared with
Ernest Walton Ernest Thomas Sinton Walton (6 October 1903 – 25 June 1995) was an Irish physicist and Nobel laureate. He is best known for his work with John Cockcroft to construct one of the earliest types of particle accelerator, the Cockcroft–Walton ...
the
Nobel Prize in Physics ) , image = Nobel Prize.png , alt = A golden medallion with an embossed image of a bearded man facing left in profile. To the left of the man is the text "ALFR•" then "NOBEL", and on the right, the text (smaller) "NAT•" then " ...
in 1951 for splitting the
atomic nucleus The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford based on the 1909 Geiger–Marsden gold foil experiment. After the discovery of the neutron ...
, and was instrumental in the development of
nuclear power Nuclear power is the use of nuclear reactions to produce electricity. Nuclear power can be obtained from nuclear fission, nuclear decay and nuclear fusion reactions. Presently, the vast majority of electricity from nuclear power is produced b ...
. After service on the
Western Front Western Front or West Front may refer to: Military frontiers * Western Front (World War I), a military frontier to the west of Germany *Western Front (World War II), a military frontier to the west of Germany *Western Front (Russian Empire), a maj ...
with the
Royal Field Artillery The Royal Field Artillery (RFA) of the British Army provided close artillery support for the infantry. It came into being when created as a distinct arm of the Royal Regiment of Artillery on 1 July 1899, serving alongside the other two arms of ...
during the
Great War World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...
, Cockcroft studied
electrical engineering Electrical engineering is an engineering discipline concerned with the study, design, and application of equipment, devices, and systems which use electricity, electronics, and electromagnetism. It emerged as an identifiable occupation in the l ...
at Manchester Municipal College of Technology whilst he was an apprentice at Metropolitan Vickers Trafford Park and was also a member of their research staff. He then won a scholarship to
St. John's College, Cambridge St John's College is a constituent college of the University of Cambridge founded by the Tudor matriarch Lady Margaret Beaufort. In constitutional terms, the college is a charitable corporation established by a charter dated 9 April 1511. The ...
, where he sat the
tripos At the University of Cambridge, a Tripos (, plural 'Triposes') is any of the examinations that qualify an undergraduate for a bachelor's degree or the courses taken by a student to prepare for these. For example, an undergraduate studying mat ...
exam in June 1924, becoming a wrangler.
Ernest Rutherford Ernest Rutherford, 1st Baron Rutherford of Nelson, (30 August 1871 – 19 October 1937) was a New Zealand physicist who came to be known as the father of nuclear physics. ''Encyclopædia Britannica'' considers him to be the greatest ...
accepted Cockcroft as a research student at the
Cavendish Laboratory The Cavendish Laboratory is the Department of Physics at the University of Cambridge, and is part of the School of Physical Sciences. The laboratory was opened in 1874 on the New Museums Site as a laboratory for experimental physics and is named ...
, and Cockcroft completed his doctorate under Rutherford's supervision in 1928. With Ernest Walton and Mark Oliphant he built what became known as a
Cockcroft–Walton generator The Cockcroft–Walton (CW) generator, or multiplier, is an electric circuit that generates a high DC voltage from a low-voltage AC or pulsing DC input. It was named after the British and Irish physicists John Douglas Cockcroft and Ernest ...
. Cockcroft and Walton used this to perform the first artificial disintegration of an atomic nucleus, a feat popularly known as ''splitting the atom''. During the
Second World War World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposi ...
Cockcroft became Assistant Director of Scientific Research in the
Ministry of Supply The Ministry of Supply (MoS) was a department of the UK government formed in 1939 to co-ordinate the supply of equipment to all three British armed forces, headed by the Minister of Supply. A separate ministry, however, was responsible for airc ...
, working on
radar Radar is a detection system that uses radio waves to determine the distance (''ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, Marine radar, ships, spacecraft, guided missiles, motor v ...
. He was also a member of the committee formed to handle issues arising from the
Frisch–Peierls memorandum The Frisch–Peierls memorandum was the first technical exposition of a practical nuclear weapon. It was written by expatriate German-Jewish physicists Otto Frisch and Rudolf Peierls in March 1940 while they were both working for Mark Oliphant a ...
, which calculated that an
atomic bomb A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission bomb) or a combination of fission and fusion reactions ( thermonuclear bomb), producing a nuclear explosion. Both bomb ...
could be technically feasible, and of the
MAUD Committee The MAUD Committee was a British scientific working group formed during the Second World War. It was established to perform the research required to determine if an atomic bomb was feasible. The name MAUD came from a strange line in a telegram fro ...
which succeeded it. In 1940, as part of the
Tizard Mission The Tizard Mission, officially the British Technical and Scientific Mission, was a British delegation that visited the United States during WWII to obtain the industrial resources to exploit the military potential of the research and development ( ...
, he shared British technology with his counterparts in the United States. Later in the war, the fruits of the Tizard Mission came back to Britain in the form of the
SCR-584 radar The SCR-584 (short for '' Set, Complete, Radio # 584'') was an automatic-tracking microwave radar developed by the MIT Radiation Laboratory during World War II. It was one of the most advanced ground-based radars of its era, and became one of th ...
set and the
proximity fuze A proximity fuze (or fuse) is a fuze that detonates an explosive device automatically when the distance to the target becomes smaller than a predetermined value. Proximity fuzes are designed for targets such as planes, missiles, ships at sea, an ...
, which were used to help defeat the
V-1 flying bomb The V-1 flying bomb (german: Vergeltungswaffe 1 "Vengeance Weapon 1") was an early cruise missile. Its official Reich Aviation Ministry () designation was Fi 103. It was also known to the Allies as the buzz bomb or doodlebug and in Germany ...
. In May 1944, he became director of the Montreal Laboratory, and oversaw the development of the
ZEEP The ZEEP (Zero Energy Experimental Pile) reactor was a nuclear reactor built at the Chalk River Laboratories near Chalk River, Ontario, Canada (which superseded the Montreal Laboratory for nuclear research in Canada). ZEEP first went critical ...
and NRX reactors, and the creation of the
Chalk River Laboratories Chalk River Laboratories (french: Laboratoires de Chalk River; also known as CRL, Chalk River Labs and formerly Chalk River Nuclear Laboratories, CRNL) is a Canadian nuclear research facility in Deep River, about north-west of Ottawa. CRL is ...
. After the war Cockcroft became the director of the
Atomic Energy Research Establishment The Atomic Energy Research Establishment (AERE) was the main centre for atomic energy research and development in the United Kingdom from 1946 to the 1990s. It was created, owned and funded by the British Government. A number of early res ...
(AERE) at Harwell, where the low-powered, graphite-moderated
GLEEP GLEEP, which stood for Graphite Low Energy Experimental Pile, was a long-lived experimental nuclear reactor in Oxfordshire, England. Run for the first time on August 15, 1947, it was the first reactor to operate in western Europe. It was built at ...
became the first nuclear reactor to operate in western Europe when it was started on 15 August 1947. This was followed by the British Experimental Pile 0 (BEPO) in 1948. Harwell was involved in the design of the reactors and the chemical separation plant at
Windscale Sellafield is a large multi-function nuclear site close to Seascale on the coast of Cumbria, England. As of August 2022, primary activities are nuclear waste storage, nuclear waste processing and storage and nuclear decommissioning. Former act ...
. Under his direction it took part in frontier fusion research, including the
ZETA Zeta (, ; uppercase Ζ, lowercase ζ; grc, ζῆτα, el, ζήτα, label= Demotic Greek, classical or ''zē̂ta''; ''zíta'') is the sixth letter of the Greek alphabet. In the system of Greek numerals, it has a value of 7. It was derived f ...
program. His insistence that the chimney stacks of the Windscale reactors be fitted with filters was mocked as ''Cockcroft's Folly'' until the core of one of the reactors ignited and released radionuclides during the Windscale fire of 1957. From 1959 to 1967, he was the first Master of
Churchill College, Cambridge Churchill College is a constituent college of the University of Cambridge, England. It has a primary focus on science, engineering and technology, but still retains a strong interest in the arts and humanities. In 1958, a trust was establis ...
. He was also chancellor of the
Australian National University The Australian National University (ANU) is a public research university located in Canberra, the capital of Australia. Its main campus in Acton encompasses seven teaching and research colleges, in addition to several national academies an ...
in
Canberra Canberra ( ) is the capital city of Australia. Founded following the federation of the colonies of Australia as the seat of government for the new nation, it is Australia's largest inland city and the eighth-largest city overall. The ci ...
from 1961 to 1965.


Early years

John Douglas Cockcroft, also known as "Johnny W.", was born in
Todmorden Todmorden ( ; ) is a market town and civil parish in the Upper Calder Valley in Calderdale, West Yorkshire, England. It is north-east of Manchester, south-east of Burnley and west of Halifax. In 2011 it had a population of 15,481. Todm ...
,
West Riding of Yorkshire The West Riding of Yorkshire is one of three historic subdivisions of Yorkshire, England. From 1889 to 1974 the administrative county County of York, West Riding (the area under the control of West Riding County Council), abbreviated County ...
, England, on 27 May 1897, the eldest son of a mill owner, John Arthur Cockcroft, and his wife Annie Maude Fielden. He had four younger brothers; Eric, Philip, Keith and Lionel. His early education was at the Church of England school in Walsden from 1901 to 1908, at Todmorden Elementary School from 1908 to 1909, and at Todmorden Secondary School from 1909 to 1914, where he played
football Football is a family of team sports that involve, to varying degrees, kicking a ball to score a goal. Unqualified, the word ''football'' normally means the form of football that is the most popular where the word is used. Sports commonly ...
and
cricket Cricket is a bat-and-ball game played between two teams of eleven players on a field at the centre of which is a pitch with a wicket at each end, each comprising two bails balanced on three stumps. The batting side scores runs by st ...
. Among the girls at the school was his future wife, Eunice Elizabeth Crabtree. In 1914, he won a County Major Scholarship,
West Riding of Yorkshire The West Riding of Yorkshire is one of three historic subdivisions of Yorkshire, England. From 1889 to 1974 the administrative county County of York, West Riding (the area under the control of West Riding County Council), abbreviated County ...
, to the
Victoria University of Manchester The Victoria University of Manchester, usually referred to as simply the University of Manchester, was a university in Manchester, England. It was founded in 1851 as Owens College. In 1880, the college joined the federal Victoria University. Afte ...
, where he studied
mathematics Mathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, shapes and the spaces in which they are contained, and quantities and their changes. These topics are represented in modern mathematics ...
. The
Great War World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...
broke out in August 1914. Cockcroft completed his first year at Manchester in June 1915. He joined the
Officers' Training Corps The Officers' Training Corps (OTC), more fully called the University Officers' Training Corps (UOTC), are military leadership training units operated by the British Army. Their focus is to develop the leadership abilities of their members whilst ...
there, but did not wish to become an
officer An officer is a person who has a position of authority in a hierarchical organization. The term derives from Old French ''oficier'' "officer, official" (early 14c., Modern French ''officier''), from Medieval Latin ''officiarius'' "an officer," f ...
. During the summer break he worked at a
YMCA YMCA, sometimes regionally called the Y, is a worldwide youth organization based in Geneva, Switzerland, with more than 64 million beneficiaries in 120 countries. It was founded on 6 June 1844 by George Williams in London, originally ...
canteen at
Kinmel Camp Kinmel Park Training Area is an army training ground in what was once the grounds of Kinmel Hall, near Abergele, in Conwy county borough, Wales. The camp was built in 1915 to train troops during the First World War and was later used to house tro ...
in Wales. He enlisted in the
British Army The British Army is the principal land warfare force of the United Kingdom, a part of the British Armed Forces along with the Royal Navy and the Royal Air Force. , the British Army comprises 79,380 regular full-time personnel, 4,090 Gurkha ...
on 24 November 1915. On 29 March 1916, he joined the 59th Training Brigade,
Royal Field Artillery The Royal Field Artillery (RFA) of the British Army provided close artillery support for the infantry. It came into being when created as a distinct arm of the Royal Regiment of Artillery on 1 July 1899, serving alongside the other two arms of ...
, where he was trained as a
signaller A signaller, signalman, colloquially referred to as a radioman or signaleer in the armed forces is a specialist soldier, sailor or airman responsible for military communications. Signallers, a.k.a. Combat Signallers or signalmen or women, are ...
. He was then posted to B Battery, 92nd Field Artillery Brigade, one of the units of the
20th (Light) Division The 20th (Light) Division was an infantry division of the British Army, part of Kitchener's Army, raised in the First World War. The division was formed in September 1914 as part of the K2 Army Group. The division landed in France July 1915 and ...
, on the
Western Front Western Front or West Front may refer to: Military frontiers * Western Front (World War I), a military frontier to the west of Germany *Western Front (World War II), a military frontier to the west of Germany *Western Front (Russian Empire), a maj ...
. Cockcroft participated in the Advance to the Hindenburg Line and the
Third Battle of Ypres The Third Battle of Ypres (german: link=no, Dritte Flandernschlacht; french: link=no, Troisième Bataille des Flandres; nl, Derde Slag om Ieper), also known as the Battle of Passchendaele (), was a campaign of the First World War, fought by ...
. He applied for a commission, and was accepted. He was sent to
Brighton Brighton () is a seaside resort and one of the two main areas of the City of Brighton and Hove in the county of East Sussex, England. It is located south of London. Archaeological evidence of settlement in the area dates back to the Bronze A ...
in February 1918 to learn about gunnery, and in April 1918, to the
Officer Candidate School An officer candidate school (OCS) is a military school which trains civilians and enlisted personnel in order for them to gain a commission as officers in the armed forces of a country. How OCS is run differs between countries and services. Ty ...
in
Weedon Bec Weedon Bec, usually just Weedon, is a village and parish in West Northamptonshire, England. It is close to the source of the River Nene. The population of the civil parish at the 2011 census was 2,706. Geography Weedon is around southeas ...
in
Northamptonshire Northamptonshire (; abbreviated Northants.) is a county in the East Midlands of England. In 2015, it had a population of 723,000. The county is administered by two unitary authorities: North Northamptonshire and West Northamptonshire. It ...
, where he was trained as a field artillery officer. He was commissioned as a
lieutenant A lieutenant ( , ; abbreviated Lt., Lt, LT, Lieut and similar) is a commissioned officer rank in the armed forces of many nations. The meaning of lieutenant differs in different militaries (see comparative military ranks), but it is often ...
in the Royal Field Artillery on 17 October 1918. After the war ended, Cockcroft was released from the Army in January 1919. He elected not to return to the Victoria University of Manchester, but to study
electrical engineering Electrical engineering is an engineering discipline concerned with the study, design, and application of equipment, devices, and systems which use electricity, electronics, and electromagnetism. It emerged as an identifiable occupation in the l ...
at Manchester Municipal College of Technology. Because he had completed a year at Victoria University of Manchester, he was allowed to skip the first year of the course. He received his
BSc A Bachelor of Science (BS, BSc, SB, or ScB; from the Latin ') is a bachelor's degree awarded for programs that generally last three to five years. The first university to admit a student to the degree of Bachelor of Science was the University ...
in June 1920. Miles Walker, the professor of electrical engineering there, persuaded him to take up an apprenticeship with Metropolitan Vickers. He obtained a
1851 Exhibition Scholarship The 1851 Research Fellowship is a scheme conducted by the Royal Commission for the Exhibition of 1851 to annually award a three-year research scholarship to approximately eight "young scientists or engineers of exceptional promise". The fellowshi ...
from the
Royal Commission for the Exhibition of 1851 The Royal Commission for the Exhibition of 1851 is an institution founded in 1850 to administer the international exhibition of 1851, officially called the Great Exhibition of the Works of Industry of all Nations. The Great Exhibition was held ...
, and submitted his MSc thesis on the "Harmonic Analysis for Alternating Currents" in June 1922. Walker then suggested Cockcroft sit for a scholarship to
St. John's College, Cambridge St John's College is a constituent college of the University of Cambridge founded by the Tudor matriarch Lady Margaret Beaufort. In constitutional terms, the college is a charitable corporation established by a charter dated 9 April 1511. The ...
, Walker's alma mater. Cockcroft was successful, winning a £30 scholarship and a £20 bursary awarded to undergraduates of limited means. Metropolitan Vickers gave him £50 subject to his returning after completing his degree. Walker and an aunt made up the balance of the £316 fee. As a graduate of another university, he was allowed to skip the first year of the
tripos At the University of Cambridge, a Tripos (, plural 'Triposes') is any of the examinations that qualify an undergraduate for a bachelor's degree or the courses taken by a student to prepare for these. For example, an undergraduate studying mat ...
. He sat the tripos exam in June 1924, achieved a B* as a wrangler, and was awarded his BA degree. Cockcroft married Elizabeth Crabtree on 26 August 1925, in a ceremony at the Bridge Street United Methodist Church in Todmorden. They had six children. The first, a boy known as Timothy, died in infancy. They subsequently had four daughters, Joan Dorothea (Thea), Jocelyn, Elisabeth Fielden and Catherine Helena; and another son, Christopher Hugh John.


Nuclear research

Ernest Rutherford Ernest Rutherford, 1st Baron Rutherford of Nelson, (30 August 1871 – 19 October 1937) was a New Zealand physicist who came to be known as the father of nuclear physics. ''Encyclopædia Britannica'' considers him to be the greatest ...
accepted Cockcroft as a research student at the
Cavendish Laboratory The Cavendish Laboratory is the Department of Physics at the University of Cambridge, and is part of the School of Physical Sciences. The laboratory was opened in 1874 on the New Museums Site as a laboratory for experimental physics and is named ...
on the recommendation of Miles Walker and the director of research at Metropolitan Vickers. Cockcroft enrolled as a
PhD PHD or PhD may refer to: * Doctor of Philosophy (PhD), an academic qualification Entertainment * '' PhD: Phantasy Degree'', a Korean comic series * '' Piled Higher and Deeper'', a web comic * Ph.D. (band), a 1980s British group ** Ph.D. (Ph.D. al ...
student in 1924, with a Foundation Scholarship of St John's College, and a State Scholarship. Under Rutherford's supervision, he wrote his doctoral thesis "On phenomena occurring in the condensation of molecular streams on surfaces", which was published in the ''
Proceedings of the Royal Society ''Proceedings of the Royal Society'' is the main research journal of the Royal Society. The journal began in 1831 and was split into two series in 1905: * Series A: for papers in physical sciences and mathematics. * Series B: for papers in life s ...
''. He was awarded his doctorate on 6 September 1925. During this time he was an assistant to the Russian physicist
Peter Kapitza Pyotr Leonidovich Kapitsa or Peter Kapitza (Russian language, Russian: Пётр Леонидович Капица, Romanian language, Romanian: Petre Capița ( – 8 April 1984) was a leading Soviet Union, Soviet physicist and Nobel Prize in P ...
, who was working on the physics of magnetic fields in extremely low temperatures. Cockcroft helped with the design and construction of helium liquefiers. In 1919, Rutherford had succeeded in disintegrating
nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...
atoms with
alpha particle Alpha particles, also called alpha rays or alpha radiation, consist of two protons and two neutrons bound together into a particle identical to a helium-4 nucleus. They are generally produced in the process of alpha decay, but may also be prod ...
s emitted from decaying
radium Radium is a chemical element with the symbol Ra and atomic number 88. It is the sixth element in group 2 of the periodic table, also known as the alkaline earth metals. Pure radium is silvery-white, but it readily reacts with nitrogen (rat ...
atoms. This and subsequent experiments hinted at the structure of atomic nuclei. To explore it further, he needed an artificial means of creating particles with a velocity high enough to overcome the charge of the nucleus. This opened a new line of research at the Cavendish Laboratory. He assigned Cockcroft,
Thomas Allibone Thomas Edward Allibone, CBE, FRS (11 November 1903 – 9 September 2003) was an English physicist. His work included important research into particle physics, X-rays, high voltage equipment, and electron microscopes. Early life Thomas Edward A ...
and
Ernest Walton Ernest Thomas Sinton Walton (6 October 1903 – 25 June 1995) was an Irish physicist and Nobel laureate. He is best known for his work with John Cockcroft to construct one of the earliest types of particle accelerator, the Cockcroft–Walton ...
to the problem. They built what became known as a Cockcroft–Walton accelerator. Mark Oliphant designed a
proton A proton is a stable subatomic particle, symbol , H+, or 1H+ with a positive electric charge of +1 ''e'' elementary charge. Its mass is slightly less than that of a neutron and 1,836 times the mass of an electron (the proton–electron mass ...
source for them. A crucial moment came when Cockcroft read a paper by
George Gamow George Gamow (March 4, 1904 – August 19, 1968), born Georgiy Antonovich Gamov ( uk, Георгій Антонович Гамов, russian: Георгий Антонович Гамов), was a Russian-born Soviet and American polymath, theoret ...
on
quantum tunnelling Quantum tunnelling, also known as tunneling ( US) is a quantum mechanical phenomenon whereby a wavefunction can propagate through a potential barrier. The transmission through the barrier can be finite and depends exponentially on the barrie ...
. Cockcroft realised that as a result of this phenomenon, the desired effect could be achieved with much lower voltages than first thought. In fact, he calculated that protons with energy of just 300,000
electronvolt In physics, an electronvolt (symbol eV, also written electron-volt and electron volt) is the measure of an amount of kinetic energy gained by a single electron accelerating from rest through an electric potential difference of one volt in vacu ...
s would be able to penetrate a
boron Boron is a chemical element with the symbol B and atomic number 5. In its crystalline form it is a brittle, dark, lustrous metalloid; in its amorphous form it is a brown powder. As the lightest element of the '' boron group'' it has t ...
nucleus. Cockcroft and Walton worked on their accelerator for the next two years. Rutherford obtained a £1,000 grant from the University of Cambridge for them to buy a
transformer A transformer is a passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple circuits. A varying current in any coil of the transformer produces a varying magnetic flux in the transformer' ...
and other equipment they needed. Cockcroft was elected a Fellow of St. John's College on 5 November 1928. He and Walton began operating their accelerator in March 1932, bombarding
lithium Lithium (from el, λίθος, lithos, lit=stone) is a chemical element with the symbol Li and atomic number 3. It is a soft, silvery-white alkali metal. Under standard conditions, it is the least dense metal and the least dense soli ...
and
beryllium Beryllium is a chemical element with the symbol Be and atomic number 4. It is a steel-gray, strong, lightweight and brittle alkaline earth metal. It is a divalent element that occurs naturally only in combination with other elements to for ...
with high-energy protons. They expected to see
gamma ray A gamma ray, also known as gamma radiation (symbol γ or \gamma), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves, typically ...
s, which French scientists had reported, but none were found. In February 1932,
James Chadwick Sir James Chadwick, (20 October 1891 – 24 July 1974) was an English physicist who was awarded the 1935 Nobel Prize in Physics for his discovery of the neutron in 1932. In 1941, he wrote the final draft of the MAUD Report, which inspi ...
demonstrated that what had been observed were actually
neutron The neutron is a subatomic particle, symbol or , which has a neutral (not positive or negative) charge, and a mass slightly greater than that of a proton. Protons and neutrons constitute the atomic nucleus, nuclei of atoms. Since protons and ...
s. Cockcroft and Walton then switched to looking for alpha particles instead. On 14 April 1932, Walton bombarded a lithium target and noticed what he thought might be alpha particles. Cockcroft and then Rutherford were summoned, and confirmed that this was indeed the case. That evening, Cockcroft and Walton met at Rutherford's home and produced a letter for ''
Nature Nature, in the broadest sense, is the physical world or universe. "Nature" can refer to the phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. Although humans are ...
'' in which they announced their results, the first artificial disintegration of an atomic nucleus, which can be described thus: : + → 2 + 17.2 MeV This feat was popularly known as ''splitting the atom''. For this accomplishment, Cockcroft and Walton were awarded the
Hughes Medal The Hughes Medal is awarded by the Royal Society of London "in recognition of an original discovery in the physical sciences, particularly electricity and magnetism or their applications". Named after David E. Hughes, the medal is awarded wit ...
in 1938, and the
Nobel Prize in Physics ) , image = Nobel Prize.png , alt = A golden medallion with an embossed image of a bearded man facing left in profile. To the left of the man is the text "ALFR•" then "NOBEL", and on the right, the text (smaller) "NAT•" then " ...
in 1951. They went on to disintegrate
carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon ma ...
, nitrogen and
oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements ...
using protons,
deuteron Deuterium (or hydrogen-2, symbol or deuterium, also known as heavy hydrogen) is one of two stable isotopes of hydrogen (the other being protium, or hydrogen-1). The nucleus of a deuterium atom, called a deuteron, contains one proton and one n ...
s and alpha particles. They demonstrated that they had produced radioactive
isotope Isotopes are two or more types of atoms that have the same atomic number (number of protons in their nuclei) and position in the periodic table (and hence belong to the same chemical element), and that differ in nucleon numbers ( mass num ...
s, including
carbon-11 Carbon (6C) has 15 known isotopes, from to , of which and are stable. The longest-lived radioisotope is , with a half-life of years. This is also the only carbon radioisotope found in nature—trace quantities are formed cosmogenically by ...
and nitrogen-13. In 1929, Cockcroft was appointed a Supervisor in Mechanical Sciences at St John's College. He was appointed a Supervisor in Physics in 1931, and in 1933 became the junior
bursar A bursar (derived from "bursa", Latin for '' purse'') is a professional administrator in a school or university often with a predominantly financial role. In the United States, bursars usually hold office only at the level of higher education ...
, making him responsible for the upkeep of the buildings, many of which were suffering from neglect. The college
gatehouse A gatehouse is a type of fortified gateway, an entry control point building, enclosing or accompanying a gateway for a town, religious house, castle, manor house, or other fortification building of importance. Gatehouses are typically the mo ...
had to be partly taken down in order to repair damage done by
deathwatch beetle The deathwatch beetle (''Xestobium rufovillosum'') is a species of woodboring beetle that sometimes infests the structural timbers of old buildings. The adult beetle is brown and measures on average long. Eggs are laid in dark crevices in old w ...
s, and Cockcroft supervised rewiring of the electrics. In 1935, Rutherford appointed him the director of research at the Mond Laboratory after Kapitza, who had returned to the
Soviet Union The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen nationa ...
. He supervised the installation of new cryogenic equipment, and supervised low temperature research. He was elected a
Fellow of the Royal Society Fellowship of the Royal Society (FRS, ForMemRS and HonFRS) is an award granted by the judges of the Royal Society of London to individuals who have made a "substantial contribution to the improvement of natural knowledge, including mathemati ...
in 1936, and in 1939 was elected the
Jacksonian Professor of Natural Philosophy The Jacksonian Professorship of Natural Philosophy is one of the senior chairs in Natural and Experimental philosophy at Cambridge University, and was founded in 1782 by a bequest from the Reverend Richard Jackson. In 1782 the Reverend Richard ...
, effective 1 October 1939. Cockcroft and Walton were well aware of the limits of their accelerator. A much better design had been developed in the United States by
Ernest Lawrence Ernest Orlando Lawrence (August 8, 1901 – August 27, 1958) was an American nuclear physicist and winner of the Nobel Prize in Physics in 1939 for his invention of the cyclotron. He is known for his work on uranium-isotope separation fo ...
, which he called the
cyclotron A cyclotron is a type of particle accelerator invented by Ernest O. Lawrence in 1929–1930 at the University of California, Berkeley, and patented in 1932. Lawrence, Ernest O. ''Method and apparatus for the acceleration of ions'', filed: Jan ...
. The Cavendish Laboratory was able to keep ahead of the Americans despite having an inferior accelerator with clever physics, but Cockcroft pressed Rutherford to obtain a cyclotron for the Cavendish laboratory. Rutherford baulked at the price tag, but a £250,000 gift from Lord Austin enabled a cyclotron, based on Lawrence's design, to be built, along with a new wing to house it. Cockcroft supervised the work. The cyclotron was in operation by October 1938, and the new wing was completed in 1940. Oliphant felt that the cyclotron was not big enough, and commenced construction of a larger 60-inch cyclotron at the
University of Birmingham , mottoeng = Through efforts to heights , established = 1825 – Birmingham School of Medicine and Surgery1836 – Birmingham Royal School of Medicine and Surgery1843 – Queen's College1875 – Mason Science College1898 – Mason Univers ...
. Its construction was delayed by the outbreak of the
Second World War World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposi ...
in Europe in 1939, and it too would be obsolescent when it was completed after the war.


Second World War

At the outbreak of the Second World War, Cockcroft took up the post of Assistant Director of Scientific Research in the
Ministry of Supply The Ministry of Supply (MoS) was a department of the UK government formed in 1939 to co-ordinate the supply of equipment to all three British armed forces, headed by the Minister of Supply. A separate ministry, however, was responsible for airc ...
, working on
radar Radar is a detection system that uses radio waves to determine the distance (''ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, Marine radar, ships, spacecraft, guided missiles, motor v ...
. In 1938, Sir
Henry Tizard Sir Henry Thomas Tizard (23 August 1885 – 9 October 1959) was an English chemist, inventor and Rector of Imperial College, who developed the modern "octane rating" used to classify petrol, helped develop radar in World War II, and led the fir ...
showed Cockcroft
Chain Home Chain Home, or CH for short, was the codename for the ring of coastal Early Warning radar stations built by the Royal Air Force (RAF) before and during the Second World War to detect and track aircraft. Initially known as RDF, and given the of ...
, the ring of coastal
early warning An early warning system is a warning system that can be implemented as a chain of information communication systems and comprises sensors, event detection and decision subsystems for early identification of hazards. They work together to for ...
radar stations built by the
Royal Air Force The Royal Air Force (RAF) is the United Kingdom's air and space force. It was formed towards the end of the First World War on 1 April 1918, becoming the first independent air force in the world, by regrouping the Royal Flying Corps (RFC) an ...
(RAF) to detect and track aircraft. Now, he helped deploy scientists to help get the system fully operational. In 1940, he became part of the Advisory Council for Scientific Research and Technical Development. In April 1940, along he became a member of the Committee for the Scientific Study of Air Warfare formed to handle issues arising from the
Frisch–Peierls memorandum The Frisch–Peierls memorandum was the first technical exposition of a practical nuclear weapon. It was written by expatriate German-Jewish physicists Otto Frisch and Rudolf Peierls in March 1940 while they were both working for Mark Oliphant a ...
, which calculated that an
atomic bomb A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission bomb) or a combination of fission and fusion reactions ( thermonuclear bomb), producing a nuclear explosion. Both bomb ...
could be technically feasible. This committee was succeeded by the
MAUD Committee The MAUD Committee was a British scientific working group formed during the Second World War. It was established to perform the research required to determine if an atomic bomb was feasible. The name MAUD came from a strange line in a telegram fro ...
, of which Cockcroft was also a member, in June 1940. This committee directed the ground-breaking early research in Britain. In August 1940, Cockcroft travelled to the United States as part of the
Tizard Mission The Tizard Mission, officially the British Technical and Scientific Mission, was a British delegation that visited the United States during WWII to obtain the industrial resources to exploit the military potential of the research and development ( ...
. Because Britain had developed many new technologies but lacked the industrial capacity to fully exploit them, it was decided to share them with the United States, although that nation was not yet at war. The information provided by the Tizard Mission contained some of the greatest scientific advances made during the war. The shared technology included radar technologies, in particular the greatly improved
cavity magnetron The cavity magnetron is a high-power vacuum tube used in early radar systems and currently in microwave ovens and linear particle accelerators. It generates microwaves using the interaction of a stream of electrons with a magnetic field whi ...
designed by Oliphant's group at Birmingham, which the American historian
James Phinney Baxter III James Phinney Baxter III (February 15, 1893 in Portland, Maine – June 17, 1975 in Williamstown, Massachusetts) was an American historian, educator, and academic, who won the 1947 Pulitzer Prize for History for his book ''Scientists Against Time ...
described as "the most valuable cargo ever brought to our shores", the design for the
proximity fuze A proximity fuze (or fuse) is a fuze that detonates an explosive device automatically when the distance to the target becomes smaller than a predetermined value. Proximity fuzes are designed for targets such as planes, missiles, ships at sea, an ...
, details of
Frank Whittle Air Commodore Sir Frank Whittle, (1 June 1907 – 8 August 1996) was an English engineer, inventor and Royal Air Force (RAF) air officer. He is credited with inventing the turbojet engine. A patent was submitted by Maxime Guillaume in 1921 fo ...
's
jet engine A jet engine is a type of reaction engine discharging a fast-moving jet (fluid), jet of heated gas (usually air) that generates thrust by jet propulsion. While this broad definition can include Rocket engine, rocket, Pump-jet, water jet, and ...
and the Frisch–Peierls memorandum describing the feasibility of an atomic bomb. Though these may be considered the most significant, many other items were also transported, including designs for rockets, superchargers, gunsights and submarine detection devices. He returned to Britain in December 1940. Soon after his return, Cockcroft was appointed Chief Superintendent of the Air Defence Research Development Establishment (ADRDE) at
Christchurch Christchurch ( ; mi, Ōtautahi) is the largest city in the South Island of New Zealand and the seat of the Canterbury Region. Christchurch lies on the South Island's east coast, just north of Banks Peninsula on Pegasus Bay. The Avon Rive ...
, Hampshire. His focus was on the use of radar for shooting down enemy aircraft. The
GL Mk. III radar Radar, Gun Laying, Mark III, or GL Mk. III for short, was a radar system used by the British Army to directly guide, or ''lay'', anti-aircraft artillery (AA). The GL Mk. III was not a single radar, but a family of related designs that saw constan ...
was developed as a target tracking and predicting radar, but by 1942 the
SCR-584 radar The SCR-584 (short for '' Set, Complete, Radio # 584'') was an automatic-tracking microwave radar developed by the MIT Radiation Laboratory during World War II. It was one of the most advanced ground-based radars of its era, and became one of th ...
developed for the same purpose in the United States became available, and Cockcroft recommended that it be acquired under
Lend-Lease Lend-Lease, formally the Lend-Lease Act and introduced as An Act to Promote the Defense of the United States (), was a policy under which the United States supplied the United Kingdom, the Soviet Union and other Allied nations with food, oil, ...
. On his own initiative, he acquired SCR-584 sets for testing, and trials conducted on the
Isle of Sheppey The Isle of Sheppey is an island off the northern coast of Kent, England, neighbouring the Thames Estuary, centred from central London. It has an area of . The island forms part of the local government district of Swale. ''Sheppey'' is deriv ...
in October 1943 conclusively demonstrated that SCR-584 was superior. This made Cockcroft very unpopular at the Ministry of Supply, but he had intelligence that the Germans were planning to deploy the
V-1 flying bomb The V-1 flying bomb (german: Vergeltungswaffe 1 "Vengeance Weapon 1") was an early cruise missile. Its official Reich Aviation Ministry () designation was Fi 103. It was also known to the Allies as the buzz bomb or doodlebug and in Germany ...
. On 1 January 1944, Lieutenant-General Sir Ronald Weeks sent Washington an urgent request for 134 SCR-584 sets. The
proximity fuze A proximity fuze (or fuse) is a fuze that detonates an explosive device automatically when the distance to the target becomes smaller than a predetermined value. Proximity fuzes are designed for targets such as planes, missiles, ships at sea, an ...
had been pioneered by Alan Butement. The idea was that if a shell could explode when it was near an enemy aircraft, a near miss would be nearly as effective as a direct hit. The technical problem was to miniaturise a radar set, and make it sturdy enough to be fired from a gun barrel. The second problem had been solved by the Germans; a dud German bomb was salvaged that had
valves A valve is a device or natural object that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways. Valves are technically fitting ...
that could withstand the acceleration. Plans were given to the Americans by the Tizard Mission, but work continued in Britain, where a team was established at Christchurch under
Charles Drummond Ellis Sir Charles Drummond Ellis (b. Hampstead, 11 August 1895; died Cookham 10 January 1980) was an English physicist and scientific administrator. His work on the magnetic spectrum of the beta-rays helped to develop a better understanding of nuclear ...
in February 1942. Work proceeded fitfully, and by 1943, production was still two years away. On a visit to the United States in November 1943, Cockcroft discussed adapting the American proximity fuze for British use with
Merle Tuve Merle Anthony Tuve (June 27, 1901 – May 20, 1982) was an American geophysicist who was the Chairman of the Office of Scientific Research and Development's Section T, which was created in August 1940. He was founding director of the Johns Hopkins ...
. As a result, 150,000 fuzes for
QF 3.7-inch AA gun The QF 3.7-inch AA was Britain's primary heavy anti-aircraft gun during World War II. It was roughly the equivalent of the German Flak 8.8 cm and American 90 mm, but with a slightly larger calibre of 3.7 inches, approximately 94 mm. ...
s were ordered on 16 January 1944. The fuzes arrived in time to engage the V-1 flying bombs in August 1944, shooting down 97 per cent of them. For his services, he was made a
Commander of the Order of the British Empire The Most Excellent Order of the British Empire is a British order of chivalry, rewarding contributions to the arts and sciences, work with charitable and welfare organisations, and public service outside the civil service. It was established ...
in June 1944. In August 1943, the
Quebec Agreement The Quebec Agreement was a secret agreement between the United Kingdom and the United States outlining the terms for the coordinated development of the science and engineering related to nuclear energy and specifically nuclear weapons. It was ...
subsumed the British
Tube Alloys Tube Alloys was the research and development programme authorised by the United Kingdom, with participation from Canada, to develop nuclear weapons during the Second World War. Starting before the Manhattan Project in the United States, the ...
project into the
Manhattan Project The Manhattan Project was a research and development undertaking during World War II that produced the first nuclear weapons. It was led by the United States with the support of the United Kingdom and Canada. From 1942 to 1946, the project w ...
, and established the
Combined Policy Committee The Quebec Agreement was a secret agreement between the United Kingdom and the United States outlining the terms for the coordinated development of the science and engineering related to nuclear energy and specifically nuclear weapons. It was ...
to control the Manhattan Project. A final agreement was spelt out on 20 May 1944. Under it, the Americans would assist with the construction of a heavy water-
moderated Moderation is the process of eliminating or lessening extremes. It is used to ensure normality throughout the medium on which it is being conducted. Common uses of moderation include: *Ensuring consistency and accuracy in the marking of stud ...
nuclear reactor A nuclear reactor is a device used to initiate and control a fission nuclear chain reaction or nuclear fusion reactions. Nuclear reactors are used at nuclear power plants for electricity generation and in nuclear marine propulsion. Heat fr ...
in Canada, and would provide technical assistance with matters such as corrosion and the effects of radiation on materials. They would not provide details about
plutonium Plutonium is a radioactive chemical element with the symbol Pu and atomic number 94. It is an actinide metal of silvery-gray appearance that tarnishes when exposed to air, and forms a dull coating when oxidized. The element normally exh ...
chemistry or metallurgy, although irradiated uranium slugs were made available for the British to work it out for themselves. A sticking point was the director of the Montreal Laboratory,
Hans von Halban Hans Heinrich von Halban (24 January 1908 – 28 November 1964) was a French physicist, of Austrian- Jewish descent. Family He was descended on his father's side from Polish Jews, who left Kraków for Vienna in the 1850s. His grandfather, Hei ...
, who was a poor administrator, did not work well with the Canadians, and was regarded as a security risk by the Americans. In April 1944 a Combined Policy Committee meeting at Washington agreed that Montreal Laboratory scientists who were not British subjects would leave, and Cockcroft would become the new director of the Montreal Laboratory in May 1944. On 24 August 1944, the decision was taken to build a small reactor in order to test the Montreal Laboratory's calculations relating to such matters as lattice dimensions, sheathing materials, and
control rod Control rods are used in nuclear reactors to control the rate of fission of the nuclear fuel – uranium or plutonium. Their compositions include chemical elements such as boron, cadmium, silver, hafnium, or indium, that are capable of absorbing ...
s, before proceeding with the full-scale NRX reactor. This was named
ZEEP The ZEEP (Zero Energy Experimental Pile) reactor was a nuclear reactor built at the Chalk River Laboratories near Chalk River, Ontario, Canada (which superseded the Montreal Laboratory for nuclear research in Canada). ZEEP first went critical ...
, for Zero Energy Experimental Pile. Building reactors in downtown Montreal was out of the question; the Canadians selected, and Groves approved, a site at
Chalk River Chalk River (2016 population: 1029) is a small rural village, part of the Laurentian Hills municipality in Renfrew County, Ontario, Canada. It is located in the Upper Ottawa Valley along Highway 17 (Trans-Canada Highway), inland (west) from ...
, Ontario, on the south bank of the
Ottawa River The Ottawa River (french: Rivière des Outaouais, Algonquin: ''Kichi-Sìbì/Kitchissippi'') is a river in the Canadian provinces of Ontario and Quebec. It is named after the Algonquin word 'to trade', as it was the major trade route of Eastern ...
some north west of Ottawa. The
Chalk River Laboratories Chalk River Laboratories (french: Laboratoires de Chalk River; also known as CRL, Chalk River Labs and formerly Chalk River Nuclear Laboratories, CRNL) is a Canadian nuclear research facility in Deep River, about north-west of Ottawa. CRL is ...
opened in 1944, and the Montreal Laboratory was closed in July 1946. ZEEP went critical on 5 September 1945, becoming the first operating nuclear reactor outside the United States. The larger NRX followed on 21 July 1947. With five times the
neutron flux The neutron flux, φ, is a scalar quantity used in nuclear physics and nuclear reactor physics. It is the total length travelled by all free neutrons per unit time and volume. Equivalently, it can be defined as the number of neutrons travellin ...
of any other reactor, it was the most powerful
research reactor Research reactors are nuclear fission-based nuclear reactors that serve primarily as a neutron source. They are also called non-power reactors, in contrast to power reactors that are used for electricity production, heat generation, or marit ...
in the world. Originally designed in July 1944 with an output of 8 MW, the power was raised to 10 MW through design 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 shocked when he was informed on 10 September 1945 that the British physicist
Alan Nunn May Alan Nunn May (sometimes Allan) (2 May 1911 – 12 January 2003) was a British physicist and a confessed and convicted Soviet spy who supplied secrets of British and American atomic research to the Soviet Union during World War II. Early lif ...
, who worked at the Chalk River Laboratories, was a 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 reduced, an act he later regretted.


Post war

In April 1945, Cockcroft and Oliphant scouted a site for a similar establishment in Britain, settling on
RAF Harwell Royal Air Force Harwell or more simply RAF Harwell is a former Royal Air Force station, near the village of Harwell, located south east of Wantage, Oxfordshire and north west of Reading, Berkshire, England. The site is now the Harwell Sci ...
. Cockcroft was offered the directorship of the
Atomic Energy Research Establishment The Atomic Energy Research Establishment (AERE) was the main centre for atomic energy research and development in the United Kingdom from 1946 to the 1990s. It was created, owned and funded by the British Government. A number of early res ...
(AERE) at Harwell on 9 November 1945. The official announcement was made on 29 January 1946, but the news leaked two months before the announcement, and before the Canadian government was informed, creating a diplomatic incident. It was agreed that Cockcroft would not depart until a successor was found, and he did not depart Chalk River for Harwell until 30 September 1946. In the meantime he recruited staff for the new laboratory.
Klaus Fuchs Klaus Emil Julius Fuchs (29 December 1911 – 28 January 1988) was a German theoretical physicist and atomic spy who supplied information from the American, British and Canadian Manhattan Project to the Soviet Union during and shortly af ...
from the Manhattan Project's
Los Alamos Laboratory The Los Alamos Laboratory, also known as Project Y, was a secret laboratory established by the Manhattan Project and operated by the University of California during World War II. Its mission was to design and build the first atomic bombs. Ro ...
became head of the Theoretical Physics; Robert Spence, Cockcroft's deputy at Montreal Laboratory, became head of Chemistry; H.W.B. Skinner, of General Physics; Otto Frisch, of Nuclear Physics; and John Dunworth, of Reactor Physics. Fuchs was later arrested as a Soviet spy on 3 February 1950. The low-powered, graphite-moderated
GLEEP GLEEP, which stood for Graphite Low Energy Experimental Pile, was a long-lived experimental nuclear reactor in Oxfordshire, England. Run for the first time on August 15, 1947, it was the first reactor to operate in western Europe. It was built at ...
, which stood for Graphite Low Energy Experimental Pile, was designed by the Montreal Laboratory, and became the first nuclear reactor to operate in Western Europe when it was started on 15 August 1947. This was followed by BEPO, a 6 MW research reactor designed by AERE, on 3 July 1948. Because heavy water was unavailable in Britain, BEPO was designed and built as a graphite-moderated reactor. Harwell was involved in the design of reactors at
Windscale Sellafield is a large multi-function nuclear site close to Seascale on the coast of Cumbria, England. As of August 2022, primary activities are nuclear waste storage, nuclear waste processing and storage and nuclear decommissioning. Former act ...
, and the chemical separation plant there. The passage of the
Atomic Energy Act of 1946 The Atomic Energy Act of 1946 (McMahon Act) determined how the United States would control and manage the nuclear technology it had jointly developed with its World War II allies, the United Kingdom and Canada. Most significantly, the Act ruled ...
(McMahon Act) in August 1946, made it clear that the UK would no longer be allowed access to the United States' atomic research. This partly resulted from the arrest for espionage of Alan Nunn May in February 1946. Cockcroft helped negotiate a new, more informal and unsigned agreement with the Americans that was announced on 7 January 1948, known as the ''Modus Vivendi''. The renewed cooperation that he hoped for under the agreement proved illusory. The development of the independent British nuclear deterrent led to the Atomic Energy Act being amended in 1958, and to a resumption of the nuclear Special Relationship between America and Britain under the 1958 US–UK Mutual Defence Agreement. Under Cockcroft's direction, AERE took part in frontier fusion research in the post-war years, including the
ZETA Zeta (, ; uppercase Ζ, lowercase ζ; grc, ζῆτα, el, ζήτα, label= Demotic Greek, classical or ''zē̂ta''; ''zíta'') is the sixth letter of the Greek alphabet. In the system of Greek numerals, it has a value of 7. It was derived f ...
program. Sir
George Paget Thomson Sir George Paget Thomson, FRS (; 3 May 189210 September 1975) was a British physicist and Nobel laureate in physics recognized for his discovery of the wave properties of the electron by electron diffraction. Education and early life Thomson ...
began research in
nuclear fusion Nuclear fusion is a reaction in which two or more atomic nuclei are combined to form one or more different atomic nuclei and subatomic particles ( neutrons or protons). The difference in mass between the reactants and products is manife ...
at
Imperial College London Imperial College London (legally Imperial College of Science, Technology and Medicine) is a public research university in London, United Kingdom. Its history began with Prince Albert, consort of Queen Victoria, who developed his vision for a cu ...
in 1946. This was subsequently transferred to the
Associated Electrical Industries Associated Electrical Industries (AEI) was a British holding company formed in 1928 through the merger of the British Thomson-Houston Company (BTH) and Metropolitan-Vickers electrical engineering companies. In 1967 AEI was acquired by GEC, to c ...
Laboratory at
Aldermaston Aldermaston is a village and civil parish in Berkshire, England. In the 2011 Census, the parish had a population of 1015. The village is in the Kennet Valley and bounds Hampshire to the south. It is approximately from Newbury, Basingstok ...
, under Allibone's direction. Research independently began at
Oxford University Oxford () is a city in England. It is the county town and only city of Oxfordshire. In 2020, its population was estimated at 151,584. It is north-west of London, south-east of Birmingham and north-east of Bristol. The city is home to the ...
under Peter Thonemann. In 1951, Cockcroft arranged for the Oxford group to be transferred to Harwell. Cockcroft approved the construction of ZETA (Zero Energy Thermonuclear Assembly) by the Thonemann's Harwell group, and the smaller
Sceptre A sceptre is a staff or wand held in the hand by a ruling monarch as an item of royal or imperial insignia. Figuratively, it means royal or imperial authority or sovereignty. Antiquity Ancient Egypt and Mesopotamia The '' Was'' and other ...
by Allibone's AEI group.
James L. Tuck James Leslie Tuck OBE, (9 January 1910 – 15 December 1980) was a British physicist. He was born in Manchester, England, and educated at the Victoria University of Manchester. Because of his involvement with the Manhattan Project, he was unable ...
's group at the Los Alamos Laboratory was also researching fusion, and Cockcroft struck an agreement with the Americans that they would release their results together, which was done in 1958. Despite Cockcroft's perennial optimism that a breakthrough was imminent, fusion power remained an elusive goal.


Cockcroft's Folly

As director of the AERE, Cockcroft famously insisted that the chimney stacks of the Windscale plutonium production reactors be fitted, at great expense, with high-performance filters. That was in response to a report that uranium oxide had been found in the vicinity of the X-10 Graphite Reactor in Oak Ridge, Tennessee. Because it was decided to fit them after the stacks had been designed, the filters became pronounced lumps at the top of the chimneys. The reactors had been designed to remain clean and uncorroded during use, so it was thought there would be no particulate for the filters to catch. As well, the uranium oxide at Oak Ridge turned out to be from the chemical plant and not the reactor. The filters therefore became known as "Cockcroft's Folly". However, when the core of one of the two reactors ignited the Windscale fire of 1957, the filters prevented a far worse release of radioactive material. Terence Price, future scientific advisor at the Ministry of Defence in the 1960s, noted that "the word folly did not seem appropriate after the accident".


Later life

On 24 January 1959,
Churchill College, Cambridge Churchill College is a constituent college of the University of Cambridge, England. It has a primary focus on science, engineering and technology, but still retains a strong interest in the arts and humanities. In 1958, a trust was establis ...
, was formally recognised by the University. Two days later, the Trustees announced that Cockcroft would be its first Master. Although it would also teach the humanities and social sciences, 70 per cent of the student body would study science and technology related subjects. He nominated the first fellows, and he oversaw the initial construction. Controversy arose over the chapel. A 1961 plan to build it at the entrance to the college, as was traditional at Cambridge, led to the immediate resignation of
Francis Crick Francis Harry Compton Crick (8 June 1916 – 28 July 2004) was an English molecular biologist, biophysicist, and neuroscientist. He, James Watson, Rosalind Franklin, and Maurice Wilkins played crucial roles in deciphering the helical stru ...
, a staunch atheist, as a fellow. The first undergraduates arrived in 1961, and the college, still incomplete, was formally opened by
Prince Philip, Duke of Edinburgh Prince Philip, Duke of Edinburgh (born Prince Philip of Greece and Denmark, later Philip Mountbatten; 10 June 1921 – 9 April 2021) was the husband of Queen Elizabeth II. As such, he served as the consort of the British monarch from E ...
, on 5 June 1964. Cockcroft was president of the
Institute of Physics The Institute of Physics (IOP) is a UK-based learned society and professional body that works to advance physics education, research and application. It was founded in 1874 and has a worldwide membership of over 20,000. The IOP is the Physic ...
from 1954 to 1956, and of the
British Association for the Advancement of Science The British Science Association (BSA) is a charity and learned society founded in 1831 to aid in the promotion and development of science. Until 2009 it was known as the British Association for the Advancement of Science (BA). The current Chi ...
. He served as chancellor of the
Australian National University The Australian National University (ANU) is a public research university located in Canberra, the capital of Australia. Its main campus in Acton encompasses seven teaching and research colleges, in addition to several national academies an ...
in
Canberra Canberra ( ) is the capital city of Australia. Founded following the federation of the colonies of Australia as the seat of government for the new nation, it is Australia's largest inland city and the eighth-largest city overall. The ci ...
from 1961 to 1965, a largely symbolic post that involved a visit once a year for degree conferring ceremonies. He delivered the
Rutherford Memorial Lecture The Institute of Physics (IOP) is a UK-based learned society and professional body that works to advance physics education, research and application. It was founded in 1874 and has a worldwide membership of over 20,000. The IOP is the Physica ...
in 1944. He was the British delegate on the Council of
CERN The European Organization for Nuclear Research, known as CERN (; ; ), is an intergovernmental organization that operates the largest particle physics laboratory in the world. Established in 1954, it is based in a northwestern suburb of Gen ...
as well as Chairman of the Nuclear Physics Sub-Committee of the
Department of Scientific and Industrial Research Department of Scientific and Industrial Research, abbreviated DSIR was the name of several British Empire organisations founded after the 1923 Imperial Conference to foster intra-Empire trade and development. * Department of Scientific and Industria ...
. In addition to winning, along with Walton, the Hughes Medal and 1951 Nobel Prize in Physics, Cockcroft received numerous awards and accolades over the years. He became a
knight bachelor The title of Knight Bachelor is the basic rank granted to a man who has been knighted by the monarch but not inducted as a member of one of the organised orders of chivalry; it is a part of the British honours system. Knights Bachelor are ...
in January 1948. This was normal: scientists were seldom inducted into the
chivalric order An order of chivalry, order of knighthood, chivalric order, or equestrian order is an order of knights, typically founded during or inspired by the original Catholic military orders of the Crusades ( 1099–1291) and paired with medieval conc ...
s, but he was created a
Knight Commander of the Order of the Bath The Most Honourable Order of the Bath is a British order of chivalry founded by George I of Great Britain, George I on 18 May 1725. The name derives from the elaborate medieval ceremony for appointing a knight, which involved Bathing#Medieval ...
in May 1953. Perhaps because this was rare, scientists normally regarded becoming a member of the
Order of Merit The Order of Merit (french: link=no, Ordre du Mérite) is an order of merit for the Commonwealth realms, recognising distinguished service in the armed forces, science, art, literature, or for the promotion of culture. Established in 1902 by ...
as a greater honour; Cockcroft became an Order of Merit member in December 1956. He also received the
Royal Medal The Royal Medal, also known as The Queen's Medal and The King's Medal (depending on the gender of the monarch at the time of the award), is a silver-gilt medal, of which three are awarded each year by the Royal Society, two for "the most important ...
in 1954, the
Faraday Medal The Faraday Medal is a top international medal awarded by the UK Institution of Engineering and Technology (IET) (previously called the Institution of Electrical Engineers (IEE)). It is part of the IET Achievement Medals collection of awards. ...
in 1955, the American
Medal of Freedom The Presidential Medal of Freedom is the highest civilian award of the United States, along with the Congressional Gold Medal. It is an award bestowed by the president of the United States to recognize people who have made "an especially merit ...
in 1947 and
Atoms for Peace Award The Atoms for Peace Award was established in 1955 through a grant of $1,000,000 by the Ford Motor Company Fund. An independent nonprofit corporation was set up to administer the award for the development or application of peaceful nuclear technol ...
in 1961, He was made a
Chevalier de la Légion d'Honneur The National Order of the Legion of Honour (french: Ordre national de la Légion d'honneur), formerly the Royal Order of the Legion of Honour ('), is the highest French order of merit, both military and civil. Established in 1802 by Napoleon B ...
by France in 1952, and was awarded the Knight Commander of the Military Order of Christ by Portugal in 1955, and the Grand Cross of the Order of Alfonso X by Spain in 1958. Cockcroft died from a
heart attack A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which ma ...
at his home at Churchill College, Cambridge, on 18 September 1967. He is buried at the Parish of the Ascension Burial Ground in Cambridge, in the same grave as his son Timothy. A memorial service was held at
Westminster Abbey Westminster Abbey, formally titled the Collegiate Church of Saint Peter at Westminster, is an historic, mainly Gothic church in the City of Westminster, London, England, just to the west of the Palace of Westminster. It is one of the United ...
on 17 October 1967. Several buildings in the United Kingdom are named after him: the Cockcroft building at the
New Museums Site The New Museums Site is a major site of the University of Cambridge, located on Pembroke Street and Free School Lane, sandwiched between Corpus Christi College, Pembroke College and Lion Yard. Its postcode is CB2 3QH. The smaller and older of ...
of the
University of Cambridge , mottoeng = Literal: From here, light and sacred draughts. Non literal: From this place, we gain enlightenment and precious knowledge. , established = , other_name = The Chancellor, Masters and Schola ...
, comprising a lecture theatre and several hardware laboratories; the
Cockcroft Institute The Cockcroft Institute is an international centre for Accelerator Science and Technology (AST) in the UK. It was proposed in September 2003 and officially opened in September 2006. It is a joint venture of Lancaster University, the University ...
at Daresbury Laboratory in Cheshire; the Cockcroft building of the
University of Brighton The University of Brighton is a public university based on four campuses in Brighton and Eastbourne on the south coast of England. Its roots can be traced back to 1858 when the Brighton School of Art was opened in the Royal Pavilion. It achi ...
; and the Cockcroft building of the
University of Salford , caption = Coat of ArmsUniversity of Salford , mottoeng = "Let us seek higher things" , established = 1850 - Pendleton Mechanics Institute 1896 – Royal Technical Institute, Salford 1967 – gained ...
. The oldest building at the
Research School of Physical Sciences and Engineering The Research School of Physics (RSPhys) was established with the creation of the Australian National University (ANU) in 1947. Located at the ANU's main campus in Canberra, the school is one of the four founding research schools in the ANU's Ins ...
, Australian National University, the Cockcroft building, is named after him. Cockcroft's papers are held at the
Churchill Archives Centre The Churchill Archives Centre (CAC) at Churchill College at the University of Cambridge is one of the largest repositories in the United Kingdom for the preservation and study of modern personal papers. It is best known for housing the papers of ...
in Cambridge, and are accessible to the public. They include his lab books, correspondence, photographs (with dozens depicting the construction of Chalk River, CKFT 26/4), theses and political papers.


Notes


References

* * * * * * * * *


Further reading

*


External links


Oral history interview transcript with John Cockcroft on 2 May 1963, American Institute of Physics, Niels Bohr Library & Archives

Oral history interview transcript with John Cockcroft on 28 March 1967, American Institute of Physics, Niels Bohr Library & Archives
*
Biography
from
Churchill Archives Centre The Churchill Archives Centre (CAC) at Churchill College at the University of Cambridge is one of the largest repositories in the United Kingdom for the preservation and study of modern personal papers. It is best known for housing the papers of ...
*
Another Nobel biography

1958 visit at the Joint Institute for Nuclear Research (Объединённый институт ядерных исследований) in Dubna (UdSSR)
* {{DEFAULTSORT:Cockcroft, John 1897 births 1967 deaths 20th-century British physicists People from Todmorden Alumni of St John's College, Cambridge Fellows of St John's College, Cambridge Fellows of Churchill College, Cambridge Masters of Churchill College, Cambridge Jacksonian Professors of Natural Philosophy Alumni of the Victoria University of Manchester Alumni of the University of Manchester Institute of Science and Technology British Army personnel of World War I Royal Artillery soldiers Experimental physicists English nuclear physicists Nobel laureates in Physics Knights Commander of the Order of the Bath Commanders of the Order of the British Empire Members of the Order of Merit Fellows of the Royal Society Royal Medal winners Knights Bachelor Atoms for Peace Award recipients Chief Scientific Advisers to the Ministry of Defence Presidents of the Institute of Physics Presidents of the Physical Society Presidents of the British Science Association English Nobel laureates Niels Bohr International Gold Medal recipients Chancellors of the Australian National University Manhattan Project people Recipients of the Medal of Freedom Presidents of the Association for Science Education People associated with the nuclear weapons programme of the United Kingdom People associated with CERN