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 from Danish physicist Niels Bohr referring to his housekeeper, Maud Ray.
132-594: The MAUD Committee was founded in response to the Frisch–Peierls memorandum , which was written in March 1940 by Rudolf Peierls and Otto Frisch , two physicists who were refugees from Nazi Germany working at the University of Birmingham under the direction of Mark Oliphant . The memorandum argued that a small sphere of pure uranium-235 could have the explosive power of thousands of tons of TNT . The chairman of
264-513: A misnomer , as their energy comes from the nucleus of the atom, just as it does with fusion weapons. In fission weapons, a mass of fissile material ( enriched uranium or plutonium ) is forced into supercriticality —allowing an exponential growth of nuclear chain reactions —either by shooting one piece of sub-critical material into another (the "gun" method) or by compression of a sub-critical sphere or cylinder of fissile material using chemically fueled explosive lenses . The latter approach,
396-665: A policy of deliberate ambiguity , it does not acknowledge having them. Germany , Italy , Turkey , Belgium , the Netherlands , and Belarus are nuclear weapons sharing states. South Africa is the only country to have independently developed and then renounced and dismantled its nuclear weapons. The Treaty on the Non-Proliferation of Nuclear Weapons aims to reduce the spread of nuclear weapons, but there are different views of its effectiveness. There are two basic types of nuclear weapons: those that derive
528-533: A "column", consisting of a vertical tube with a hot wire down the centre. The advantage of the technique was that it was simple in design and there were no moving parts. But it could take months to reach equilibrium, required a lot of energy, and needed high temperatures that could cause a problem with the uranium hexafluoride. Another line of research at Liverpool was measuring the fission cross section of uranium-235, on which Frisch and Peierls' calculations depended. They had assumed that almost every collision between
660-659: A Nobel Prize winner, and George B. Pegram were sent to the UK to obtain more information. In January 1942, the OSRD was empowered to engage in large engineering projects in addition to research. Without the help of the MAUD Committee the Manhattan Project would have started months behind. Instead they were able to begin thinking about how to create a bomb, not whether it was possible. Gowing noted that "events that change
792-696: A conference—called for in the manifesto—in Pugwash, Nova Scotia , Eaton's birthplace. This conference was to be the first of the Pugwash Conferences on Science and World Affairs , held in July 1957. By the 1960s, steps were taken to limit both the proliferation of nuclear weapons to other countries and the environmental effects of nuclear testing . The Partial Nuclear Test Ban Treaty (1963) restricted all nuclear testing to underground nuclear testing , to prevent contamination from nuclear fallout, whereas
924-457: A confined space, but a nuclear explosion will not do this. Peierls, Fuchs, Geoffrey Taylor and J. G. Kynch worked out the hydrodynamics to refute Kistiakowsky's argument. Taylor produced a paper on "The Formation of a Blast Wave by a Very Intense Explosion" in June 1941. The first draft of the final report of the MAUD Committee was written by Thomson in June 1941, and circulated among members of
1056-458: A faster and less vulnerable attack, the development of long-range intercontinental ballistic missiles (ICBMs) and submarine-launched ballistic missiles (SLBMs) has given some nations the ability to plausibly deliver missiles anywhere on the globe with a high likelihood of success. More advanced systems, such as multiple independently targetable reentry vehicles (MIRVs), can launch multiple warheads at different targets from one missile, reducing
1188-614: A few nations possess such weapons or are suspected of seeking them. The only countries known to have detonated nuclear weapons—and acknowledge possessing them—are (chronologically by date of first test) the United States , the Soviet Union (succeeded as a nuclear power by Russia ), the United Kingdom , France , China , India , Pakistan , and North Korea . Israel is believed to possess nuclear weapons, though, in
1320-555: A fission bomb to initiate them. Such a device might provide a simpler path to thermonuclear weapons than one that required the development of fission weapons first, and pure fusion weapons would create significantly less nuclear fallout than other thermonuclear weapons because they would not disperse fission products. In 1998, the United States Department of Energy divulged that the United States had, "...made
1452-542: A five kilogram bomb would be the equivalent to several thousand tons of dynamite, and even a one kilogram bomb would be impressive. Because of the potential radioactive fallout , they thought that the British might find it morally unacceptable. Oliphant took the Frisch–Peierls memorandum to Tizard in March 1940. He passed it on to Thomson, who discussed it with Cockcroft and Oliphant. They also heard from Jacques Allier of
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#17327810688821584-421: A fusion weapon as of January 2016 , though this claim is disputed. Thermonuclear weapons are considered much more difficult to successfully design and execute than primitive fission weapons. Almost all of the nuclear weapons deployed today use the thermonuclear design because it results in an explosion hundreds of times stronger than that of a fission bomb of similar weight. Thermonuclear bombs work by using
1716-562: A meeting with the Belgian president of the company, Edgar Sengier . Since Union Minière management were friendly towards Britain, it was not considered necessary to immediately acquire the uranium, but Tizard's Committee for the Scientific Survey of Air Warfare (CSSAW) was directed to continue the research into the feasibility of atomic bombs. Thomson, at Imperial College London , and Mark Oliphant , an Australian physicist at
1848-539: A microscopic amount of pure uranium-235 in the United States, and a team under Merle Tuve at the Carnegie Institution of Washington was measuring the cross section. The uranium-235 was too valuable to send a sample to Britain, so Chadwick sent the Americans a list of measurements he wanted them to carry out. The final result was that the cross section was smaller than Frisch and Peierls had assumed, but
1980-453: A moderator for the fast neutrons. In conclusion though, while the nuclear reactor had considerable promise for future peaceful uses, the committee felt that it was not worth considering during the present war. In response to the MAUD Committee report, a nuclear weapons programme was launched. To co-ordinate the effort, a new directorate was created, with the deliberately misleading name of Tube Alloys for security purposes. Sir John Anderson ,
2112-460: A more unassuming name, the MAUD Committee. MAUD was assumed by many to be an acronym, however it is not. The name MAUD came to be in an unusual way. On 9 April 1940, the day Germany invaded Denmark , Niels Bohr had sent a telegram to Frisch. The telegram ended with a strange line "Tell Cockcroft and Maud Ray Kent". At first it was thought to be code regarding radium or other vital atomic-weapons-related information, hidden in an anagram . One suggestion
2244-472: A nation's economic electronics-based infrastructure. Because the effect is most effectively produced by high altitude nuclear detonations (by military weapons delivered by air, though ground bursts also produce EMP effects over a localized area), it can produce damage to electronics over a wide, even continental, geographical area. Research has been done into the possibility of pure fusion bombs : nuclear weapons that consist of fusion reactions without requiring
2376-614: A neutron of any energy and a uranium-235 nucleus would produce a fission. The value they used for the fission cross section was that published by French researchers in 1939, but data published by the Americans in the 15 March and 15 April 1940 issues of the American journal Physical Review indicated that it was much smaller. No pure uranium-235 was available, so experiments at Liverpool were conducted with natural uranium. The results were inconclusive, but tended to support Frisch and Peierls. By March 1941, Alfred Nier had managed to produce
2508-537: A new nuclear strategy, one that is distinct from that which gave relative stability during the Cold War. Since 1996, the United States has had a policy of allowing the targeting of its nuclear weapons at terrorists armed with weapons of mass destruction . Robert Gallucci argues that although traditional deterrence is not an effective approach toward terrorist groups bent on causing a nuclear catastrophe, Gallucci believes that "the United States should instead consider
2640-425: A nuclear war between two nations would result in mutual annihilation. From this point of view, the significance of nuclear weapons is to deter war because any nuclear war would escalate out of mutual distrust and fear, resulting in mutually assured destruction . This threat of national, if not global, destruction has been a strong motivation for anti-nuclear weapons activism. Critics from the peace movement and within
2772-411: A nuclear weapon from another country by threatening nuclear retaliation is known as the strategy of nuclear deterrence . The goal in deterrence is to always maintain a second strike capability (the ability of a country to respond to a nuclear attack with one of its own) and potentially to strive for first strike status (the ability to destroy an enemy's nuclear forces before they could retaliate). During
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#17327810688822904-465: A nuclear weapon is a gravity bomb dropped from aircraft ; this was the method used by the United States against Japan in 1945. This method places few restrictions on the size of the weapon. It does, however, limit attack range, response time to an impending attack, and the number of weapons that a country can field at the same time. With miniaturization, nuclear bombs can be delivered by both strategic bombers and tactical fighter-bombers . This method
3036-409: A nuclear weapon to its target is an important factor affecting both nuclear weapon design and nuclear strategy . The design, development, and maintenance of delivery systems are among the most expensive parts of a nuclear weapons program; they account, for example, for 57% of the financial resources spent by the United States on nuclear weapons projects since 1940. The simplest method for delivering
3168-433: A nuclear weapon with suitable materials (such as cobalt or gold ) creates a weapon known as a salted bomb . This device can produce exceptionally large quantities of long-lived radioactive contamination . It has been conjectured that such a device could serve as a "doomsday weapon" because such a large quantity of radioactivities with half-lives of decades, lifted into the stratosphere where winds would distribute it around
3300-530: A number of scientists considered whether an atomic bomb was practical. At the University of Liverpool , Chadwick and the Polish refugee scientist Joseph Rotblat tackled the problem, but their calculations were inconclusive. At Cambridge, Nobel Prize in Physics laureates George Paget Thomson and William Lawrence Bragg wanted the government to take urgent action to acquire uranium ore . The main source of this
3432-597: A paper written shortly after they arrived in England, Halban and Kowarski theorised that slow neutrons could be absorbed by uranium-238, forming uranium-239. A letter by Edwin McMillan and Philip Abelson published in the Physical Review on 15 June 1940 stated that this decayed to an element with an atomic number of 93, and then to one with an atomic number of 94 and mass of 239, which, while still radioactive,
3564-421: A policy of expanded deterrence, which focuses not solely on the would-be nuclear terrorists but on those states that may deliberately transfer or inadvertently leak nuclear weapons and materials to them. By threatening retaliation against those states, the United States may be able to deter that which it cannot physically prevent.". Graham Allison makes a similar case, arguing that the key to expanded deterrence
3696-520: A representative of Imperial Chemical Industries (ICI). Basil Dickins from the MAP acted as the secretary of the Technical Committee. Thomson chaired both committees. The MAUD Committee's research was split among four different English universities: the University of Birmingham , the University of Liverpool , the University of Cambridge and the University of Oxford . At first the research
3828-447: A significant portion of their energy from fission reactions used to "trigger" fusion reactions, and fusion reactions can themselves trigger additional fission reactions. Only six countries—the United States , Russia , the United Kingdom , China , France , and India —have conducted thermonuclear weapon tests. Whether India has detonated a "true" multi-staged thermonuclear weapon is controversial. North Korea claims to have tested
3960-416: A statement that: We should like to emphasize at the beginning of this report that we entered the project with more skepticism than belief, though we felt it was a matter which had to be investigated. As we proceeded we became more and more convinced that release of atomic energy on a large scale is possible and that conditions can be chosen which would make it a very powerful weapon of war. We have now reached
4092-550: A substantial investment" in the past to develop pure fusion weapons, but that, "The U.S. does not have and is not developing a pure fusion weapon", and that, "No credible design for a pure fusion weapon resulted from the DOE investment". Nuclear isomers provide a possible pathway to fissionless fusion bombs. These are naturally occurring isotopes ( Hf being a prominent example) which exist in an elevated energy state. Mechanisms to release this energy as bursts of gamma radiation (as in
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4224-642: A time scale by only a few months can nevertheless change history." On 16 July 1945, the Manhattan Project detonated the first atomic bomb in the Trinity nuclear test . The Soviet Union received details of British research from its atomic spies Klaus Fuchs , Engelbert Broda and Cairncross. Lavrentiy Beria , the head of the NKVD, gave a report to the General Secretary of the Communist Party of
4356-420: Is a thermonuclear weapon that yields a relatively small explosion but a relatively large amount of neutron radiation . Such a weapon could, according to tacticians, be used to cause massive biological casualties while leaving inanimate infrastructure mostly intact and creating minimal fallout. Because high energy neutrons are capable of penetrating dense matter, such as tank armor, neutron warheads were procured in
4488-721: 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 types release large quantities of energy from relatively small amounts of matter . The first test of a fission ("atomic") bomb released an amount of energy approximately equal to 20,000 tons of TNT (84 TJ ). The first thermonuclear ("hydrogen") bomb test released energy approximately equal to 10 million tons of TNT (42 PJ). Nuclear bombs have had yields between 10 tons TNT (the W54 ) and 50 megatons for
4620-456: Is analogous to identifying a criminal by fingerprints. "The goal would be twofold: first, to deter leaders of nuclear states from selling weapons to terrorists by holding them accountable for any use of their weapons; second, to give leaders every incentive to tightly secure their nuclear weapons and materials." According to the Pentagon's June 2019 " Doctrine for Joint Nuclear Operations " of
4752-403: Is coming up with ways of tracing nuclear material to the country that forged the fissile material. "After a nuclear bomb detonates, nuclear forensics cops would collect debris samples and send them to a laboratory for radiological analysis. By identifying unique attributes of the fissile material, including its impurities and contaminants, one could trace the path back to its origin." The process
4884-481: Is for the purpose of achieving different yields for different situations , and in manipulating design elements to attempt to minimize weapon size, radiation hardness or requirements for special materials, especially fissile fuel or tritium. Some nuclear weapons are designed for special purposes; most of these are for non-strategic (decisively war-winning) purposes and are referred to as tactical nuclear weapons . The neutron bomb purportedly conceived by Sam Cohen
5016-419: Is inversely proportional to the square root of the gas's molecular mass . In a container with a porous barrier containing a mixture of two gases, the lighter molecules will pass out of the container more rapidly than the heavier molecules. The gas leaving the container is slightly enriched in the lighter molecules, while the residual gas is slightly depleted. Simon's team conducted experiments with copper gauze as
5148-503: Is no evidence that it is feasible beyond the military domain. However, the U.S. Air Force funded studies of the physics of antimatter in the Cold War , and began considering its possible use in weapons, not just as a trigger, but as the explosive itself. A fourth generation nuclear weapon design is related to, and relies upon, the same principle as antimatter-catalyzed nuclear pulse propulsion . Most variation in nuclear weapon design
5280-409: Is not a fusion bomb. In the boosted bomb, the neutrons produced by the fusion reactions serve primarily to increase the efficiency of the fission bomb. There are two types of boosted fission bomb: internally boosted, in which a deuterium-tritium mixture is injected into the bomb core, and externally boosted, in which concentric shells of lithium-deuteride and depleted uranium are layered on the outside of
5412-490: Is not clear that this has ever been implemented, and their plausible use in nuclear weapons is a matter of dispute. The other basic type of nuclear weapon produces a large proportion of its energy in nuclear fusion reactions. Such fusion weapons are generally referred to as thermonuclear weapons or more colloquially as hydrogen bombs (abbreviated as H-bombs ), as they rely on fusion reactions between isotopes of hydrogen ( deuterium and tritium ). All such weapons derive
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5544-454: Is the primary means of nuclear weapons delivery; the majority of U.S. nuclear warheads, for example, are free-fall gravity bombs, namely the B61 , which is being improved upon to this day. Preferable from a strategic point of view is a nuclear weapon mounted on a missile , which can use a ballistic trajectory to deliver the warhead over the horizon. Although even short-range missiles allow for
5676-479: The Earl of Suffolk and Major Ardale Golding on the steamer Broompark . The heavy water, valued at £22,000, was initially kept at HM Prison Wormwood Scrubs , but was later secretly stored in the library at Windsor Castle . The French scientists moved to Cambridge, where they conducted experiments that conclusively showed that a nuclear chain reaction could be produced in a mixture of uranium oxide and heavy water. In
5808-697: The Lord President of the Council , became the minister responsible, and Wallace Akers from ICI was appointed the director of Tube Alloys. Tube Alloys and the Manhattan Project exchanged information, but did not initially combine their efforts, ostensibly over concerns about American security. Ironically, it was the British project that had already been penetrated by atomic spies for the Soviet Union. The most significant of them at this time
5940-695: The Starfish Prime high-altitude nuclear test in 1962, an unexpected effect was produced which is called a nuclear electromagnetic pulse . This is an intense flash of electromagnetic energy produced by a rain of high-energy electrons which in turn are produced by a nuclear bomb's gamma rays. This flash of energy can permanently destroy or disrupt electronic equipment if insufficiently shielded. It has been proposed to use this effect to disable an enemy's military and civilian infrastructure as an adjunct to other nuclear or conventional military operations. By itself it could as well be useful to terrorists for crippling
6072-554: The Tsar Bomba (see TNT equivalent ). A thermonuclear weapon weighing as little as 600 pounds (270 kg) can release energy equal to more than 1.2 megatonnes of TNT (5.0 PJ). A nuclear device no larger than a conventional bomb can devastate an entire city by blast, fire, and radiation . Since they are weapons of mass destruction , the proliferation of nuclear weapons is a focus of international relations policy. Nuclear weapons have been deployed twice in war , both by
6204-676: The Tsar Bomba of the USSR, which released an energy equivalent of over 50 megatons of TNT (210 PJ), was a three-stage weapon. Most thermonuclear weapons are considerably smaller than this, due to practical constraints from missile warhead space and weight requirements. In the early 1950s the Livermore Laboratory in the United States had plans for the testing of two massive bombs, Gnomon and Sundial , 1 gigaton of TNT and 10 gigatons of TNT respectively. Fusion reactions do not create fission products, and thus contribute far less to
6336-511: The University of Birmingham , were each tasked with carrying out a series of experiments on uranium. By February 1940, Thomson's team had failed to create a chain reaction in natural uranium, and he had decided that it was not worth pursuing. At Birmingham, Oliphant's team had reached a different conclusion. Oliphant had delegated the task to Frisch and Rudolf Peierls , two German refugee scientists who could not work on Oliphant's radar project because they were enemy aliens , and therefore lacked
6468-664: The electromagnetic separation process at the Berkeley Radiation Laboratory . Cockcroft became the director of the joint British-Canadian Montreal Laboratory . A British mission to the Los Alamos Laboratory was led by Chadwick, and later Peierls, which included several of Britain's most eminent scientists. As overall head of the British Mission, Chadwick forged a close and successful partnership, and ensured that British participation
6600-424: The hafnium controversy ) have been proposed as possible triggers for conventional thermonuclear reactions. Antimatter , which consists of particles resembling ordinary matter particles in most of their properties but having opposite electric charge , has been considered as a trigger mechanism for nuclear weapons. A major obstacle is the difficulty of producing antimatter in large enough quantities, and there
6732-553: The head of government or head of state . Despite controls and regulations governing nuclear weapons, there is an inherent danger of "accidents, mistakes, false alarms, blackmail, theft, and sabotage". In the late 1940s, lack of mutual trust prevented the United States and the Soviet Union from making progress on arms control agreements. The Russell–Einstein Manifesto was issued in London on July 9, 1955, by Bertrand Russell in
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#17327810688826864-474: The liquid drop model developed by Bohr and Fritz Kalckar to explain the mechanism of nuclear fission. Bohr had an epiphany that the fission at low energies was principally due to the uranium-235 isotope, while at high energies it was mainly due to the more abundant uranium-238 isotope. The former makes up just 0.7% of natural uranium, while the latter accounts for 99.3%. Frédéric Joliot-Curie and his Paris colleagues Hans von Halban and Lew Kowarski raised
6996-436: The tropopause into the stratosphere , where the calm non-turbulent winds permit the debris to travel great distances from the burst, eventually settling and unpredictably contaminating areas far removed from the target of the explosion. There are other types of nuclear weapons as well. For example, a boosted fission weapon is a fission bomb that increases its explosive yield through a small number of fusion reactions, but it
7128-537: The "implosion" method, is more sophisticated and more efficient (smaller, less massive, and requiring less of the expensive fissile fuel) than the former. A major challenge in all nuclear weapon designs is to ensure that a significant fraction of the fuel is consumed before the weapon destroys itself. The amount of energy released by fission bombs can range from the equivalent of just under a ton to upwards of 500,000 tons (500 kilotons ) of TNT (4.2 to 2.1 × 10 GJ). All fission reactions generate fission products ,
7260-586: The 1980s (though not deployed in Europe) for use as tactical payloads for US Army artillery shells (200 mm W79 and 155 mm W82 ) and short range missile forces. Soviet authorities announced similar intentions for neutron warhead deployment in Europe; indeed, they claimed to have originally invented the neutron bomb, but their deployment on USSR tactical nuclear forces is unverifiable. A type of nuclear explosive most suitable for use by ground special forces
7392-972: The American effort, which eventually became the Manhattan Project . The report was also revealed to the Soviet Union by its atomic spies , and helped start the Soviet atomic bomb project . The neutron was discovered by James Chadwick at the Cavendish Laboratory at the University of Cambridge in February 1932. Two months later, his Cavendish colleagues John Cockcroft and Ernest Walton split lithium atoms with accelerated protons . In December 1938, Otto Hahn and Fritz Strassmann at Hahn's laboratory in Berlin-Dahlem bombarded uranium with slow neutrons, and discovered that barium had been produced. Hahn wrote to his colleague Lise Meitner , who, with her nephew Otto Frisch , proved that
7524-425: The Cold War, policy and military theorists considered the sorts of policies that might prevent a nuclear attack, and they developed game theory models that could lead to stable deterrence conditions. Different forms of nuclear weapons delivery (see above) allow for different types of nuclear strategies. The goals of any strategy are generally to make it difficult for an enemy to launch a pre-emptive strike against
7656-746: The French Deuxième Bureau , who had been involved in the removal of the entire stock of heavy water from Norway. He told them of the interest the Germans had shown in the heavy water, and in the activity of the French researchers in Paris. Immediate action was taken: the Ministry of Economic Warfare was asked to secure stocks of uranium oxide in danger of being captured by the Germans; British intelligence agencies were asked to investigate
7788-494: The Joint Chiefs of Staffs website Publication, "Integration of nuclear weapons employment with conventional and special operations forces is essential to the success of any mission or operation." Because they are weapons of mass destruction, the proliferation and possible use of nuclear weapons are important issues in international relations and diplomacy. In most countries, the use of nuclear force can only be authorized by
7920-447: The MAP to write to firms requesting priority for items required by the scientists. There were also shortages of manpower, as chemists and physicists had been diverted to war work. Of necessity, the universities employed many aliens or ex-aliens. The MAP was initially opposed to their employment on security grounds, especially as most were from enemy or occupied countries. Their employment was only made possible because they were employed by
8052-503: The MAUD Committee at Cambridge was jointly led by Bragg and Cockcroft. It included Bretscher, Feather, Halban, Kowarski, Herbert Freundlich and Nicholas Kemmer . Paul Dirac assisted as a consultant, although he was not formally part of the team. On 19 June 1940, following the German invasion of France , Halban, Kowarski and other French scientists and their families, along with their precious stock of heavy water, were brought to England by
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#17327810688828184-678: The MAUD Committee in as good grace as Frisch and Peierls. In response, two new committees were created in March 1941 to replace the MAUD Committee and the Technical Sub-Committee, called the MAUD Policy Committee and the MAUD Technical Committee. Unlike the original two committees, they had written terms of reference. The terms of reference of the MAUD Policy Committee were: Those of the MAUD Technical Committee were: The MAUD Policy Committee
8316-507: The MAUD Committee was George Thomson . Research was split among four different universities: the University of Birmingham , University of Liverpool , University of Cambridge and the University of Oxford , each having a separate programme director. Various means of uranium enrichment were examined, as was nuclear reactor design, the properties of uranium-235, the use of the then-hypothetical element plutonium , and theoretical aspects of nuclear weapon design. After fifteen months of work,
8448-503: The Nuclear Age (1961) that mere possession of a nuclear arsenal was enough to ensure deterrence, and thus concluded that the spread of nuclear weapons could increase international stability . Some prominent neo-realist scholars, such as Kenneth Waltz and John Mearsheimer , have argued, along the lines of Gallois, that some forms of nuclear proliferation would decrease the likelihood of total war , especially in troubled regions of
8580-699: The President. The Uranium Committee became the Uranium Section of the OSRD, which was soon renamed the S-1 Section for security reasons. Bush engaged Arthur Compton , a Nobel Prize winner, and the National Academy of Sciences . His report was issued on 17 May 1941. It endorsed a stronger effort, but did not address the design or manufacture of a bomb in any detail. Information from the MAUD Committee came from British scientists travelling to
8712-473: The Soviet Union , Joseph Stalin , in March 1942 that included the MAUD reports and other British documents passed by Cairncross. In 1943 the NKVD obtained a copy of the final report by the MAUD Committee. This led Stalin to order the start of a Soviet programme, although it had very limited resources. Igor Kurchatov was appointed director of the nascent programme later that year. Six years later, on 29 August 1949,
8844-511: The Soviet Union tested an atomic bomb. Frisch%E2%80%93Peierls memorandum Too Many Requests If you report this error to the Wikimedia System Administrators, please include the details below. Request from 172.68.168.133 via cp1102 cp1102, Varnish XID 575085984 Upstream caches: cp1102 int Error: 429, Too Many Requests at Thu, 28 Nov 2024 08:04:28 GMT Atomic bomb A nuclear weapon
8976-664: The USAAF detonated a plutonium implosion-type fission bomb nicknamed " Fat Man " over the Japanese city of Nagasaki . These bombings caused injuries that resulted in the deaths of approximately 200,000 civilians and military personnel . The ethics of these bombings and their role in Japan's surrender are to this day, still subjects of debate . Since the atomic bombings of Hiroshima and Nagasaki , nuclear weapons have been detonated over 2,000 times for testing and demonstration. Only
9108-777: The USAF AIR-2 Genie , the AIM-26 Falcon and US Army Nike Hercules . Missile interceptors such as the Sprint and the Spartan also used small nuclear warheads (optimized to produce neutron or X-ray flux) but were for use against enemy strategic warheads. Other small, or tactical, nuclear weapons were deployed by naval forces for use primarily as antisubmarine weapons. These included nuclear depth bombs or nuclear armed torpedoes. Nuclear mines for use on land or at sea are also possibilities. The system used to deliver
9240-527: The United States against the Japanese cities of Hiroshima and Nagasaki in 1945 during World War II . Nuclear weapons have only twice been used in warfare, both times by the United States against Japan at the end of World War II . On August 6, 1945, the United States Army Air Forces (USAAF) detonated a uranium gun-type fission bomb nicknamed " Little Boy " over the Japanese city of Hiroshima ; three days later, on August 9,
9372-634: The United States in late August 1941, ostensibly to discuss the radar programme, but actually to find out why the United States was ignoring the MAUD Committee's findings. Oliphant reported: "The minutes and reports had been sent to Lyman Briggs, who was the Director of the Uranium Committee, and we were puzzled to receive virtually no comment. I called on Briggs in Washington, only to find out that this inarticulate and unimpressive man had put
9504-665: The United States, notably the Tizard Mission , and from American observers at the MAUD Committee meetings in April and July 1941. Cockcroft, who was part of the Tizard Mission, reported that the American project lagged behind the British one, and was not proceeding as fast. Britain was at war and felt an atomic bomb was urgent, but the US was not yet at war. It was Oliphant who pushed the American programme into action. He flew to
9636-526: The United States. Small, two-man portable tactical weapons (somewhat misleadingly referred to as suitcase bombs ), such as the Special Atomic Demolition Munition , have been developed, although the difficulty of combining sufficient yield with portability limits their military utility. Nuclear warfare strategy is a set of policies that deal with preventing or fighting a nuclear war. The policy of trying to prevent an attack by
9768-505: The activities of German nuclear scientists; and A. V. Hill , the British Scientific Attaché in Washington, was asked to find out what the Americans were up to. Hill reported that the Americans had scientists investigating the matter, but they did not think that any military applications would be found. A committee was created as a response to the Frisch–Peierls memorandum. It held its first meeting on 10 April 1940, in
9900-721: The barrier. Because uranium hexafluoride, the only known gas containing uranium, was both scarce and difficult to handle, a mixture of carbon dioxide and water vapour was used to test it. The result of this work was a report from Simon on the "Estimate of the Size of an Actual Separation Plant" in December 1940. He described an industrial plant capable of producing a kilogram per day of uranium enriched to 99 per cent uranium-235. The plant would use 70,000 square metres (750,000 sq ft) of membrane barriers, in 18,000 separation units in 20 stages. The plant would cover 40 acres (16 ha),
10032-462: The bomb and said we had no right to work on power plants or anything but the bomb. The bomb would cost 25 million dollars, he said, and Britain did not have the money or the manpower, so it was up to us." Oliphant then visited his friend Ernest Lawrence , an American Nobel Prize winner, to explain the urgency. Lawrence contacted Compton and James B. Conant , who received a copy of the final MAUD Report from Thomson on 3 October 1941. Harold Urey , also
10164-485: The chance of a successful missile defense . Today, missiles are most common among systems designed for delivery of nuclear weapons. Making a warhead small enough to fit onto a missile, though, can be difficult. Tactical weapons have involved the most variety of delivery types, including not only gravity bombs and missiles but also artillery shells, land mines , and nuclear depth charges and torpedoes for anti-submarine warfare . An atomic mortar has been tested by
10296-411: The committee on 26 June, with instructions that the next meeting on 2 July would discuss it. A considerable amount of editing was done, mainly by Chadwick. At this stage it was divided into two reports. The first was on "Use of Uranium for a Bomb"; the second one "Use of Uranium as a Source of Power". They consolidated all the research and experiments the MAUD Committee had completed. The report opened with
10428-581: The conclusion that it will be possible to make an effective uranium bomb which, containing some 25 lb of active material, would be equivalent as regards destructive effect to 1,800 tons of TNT and would also release large quantities of radioactive substances which would make places near to where the bomb exploded dangerous to human life for a long period. The first report concluded that a bomb was feasible. It described it in technical detail, and provided specific proposals for developing it, including cost estimates. A plant to produce one kilogram of uranium-235 per day
10560-435: The creation of nuclear fallout than fission reactions, but because all thermonuclear weapons contain at least one fission stage, and many high-yield thermonuclear devices have a final fission stage, thermonuclear weapons can generate at least as much nuclear fallout as fission-only weapons. Furthermore, high yield thermonuclear explosions (most dangerously ground bursts) have the force to lift radioactive debris upwards past
10692-455: The decision process. The prospect of mutually assured destruction might not deter an enemy who expects to die in the confrontation. Further, if the initial act is from a stateless terrorist instead of a sovereign nation, there might not be a nation or specific target to retaliate against. It has been argued, especially after the September 11, 2001, attacks , that this complication calls for
10824-469: The energy of a fission bomb to compress and heat fusion fuel. In the Teller-Ulam design , which accounts for all multi-megaton yield hydrogen bombs, this is accomplished by placing a fission bomb and fusion fuel ( tritium , deuterium , or lithium deuteride ) in proximity within a special, radiation-reflecting container. When the fission bomb is detonated, gamma rays and X-rays emitted first compress
10956-455: The fission bomb core. The external method of boosting enabled the USSR to field the first partially thermonuclear weapons, but it is now obsolete because it demands a spherical bomb geometry, which was adequate during the 1950s arms race when bomber aircraft were the only available delivery vehicles. The detonation of any nuclear weapon is accompanied by a blast of neutron radiation . Surrounding
11088-420: The fusion fuel, then heat it to thermonuclear temperatures. The ensuing fusion reaction creates enormous numbers of high-speed neutrons , which can then induce fission in materials not normally prone to it, such as depleted uranium . Each of these components is known as a "stage", with the fission bomb as the "primary" and the fusion capsule as the "secondary". In large, megaton-range hydrogen bombs, about half of
11220-535: The globe, would make all life on the planet extinct. In connection with the Strategic Defense Initiative , research into the nuclear pumped laser was conducted under the DOD program Project Excalibur but this did not result in a working weapon. The concept involves the tapping of the energy of an exploding nuclear bomb to power a single-shot laser that is directed at a distant target. During
11352-667: The ground-floor main committee room of the Royal Society in Burlington House in London. Its meetings were invariably held there. The original members were Thomson, Chadwick, Cockcroft, Oliphant and Philip Moon ; Patrick Blackett , Charles Ellis and Norman Haworth were subsequently added, along with a representative of the Director of Scientific Research at the Ministry of Aircraft Production (MAP). The MAUD Committee held its first two meetings in April 1940 before it
11484-491: The machinery would weigh 70,000 long tons (71,000 t) and consume 60,000 kW of power. He estimated that it would take 12 to 18 months to build at a cost of around £4 million, require 1,200 workers to operate, and cost £1.5 million per annum to run. "We are confident that the separation can be performed in the way described", he concluded, "and we even believe that the scheme is, in view of its object, not unduly expensive of time, money and effort." The division of
11616-496: The majority of their energy from nuclear fission reactions alone, and those that use fission reactions to begin nuclear fusion reactions that produce a large amount of the total energy output. All existing nuclear weapons derive some of their explosive energy from nuclear fission reactions. Weapons whose explosive output is exclusively from fission reactions are commonly referred to as atomic bombs or atom bombs (abbreviated as A-bombs ). This has long been noted as something of
11748-407: The midst of the Cold War. It highlighted the dangers posed by nuclear weapons and called for world leaders to seek peaceful resolutions to international conflict. The signatories included eleven pre-eminent intellectuals and scientists, including Albert Einstein , who signed it just days before his death on April 18, 1955. A few days after the release, philanthropist Cyrus S. Eaton offered to sponsor
11880-545: The military establishment have questioned the usefulness of such weapons in the current military climate. According to an advisory opinion issued by the International Court of Justice in 1996, the use of (or threat of use of) such weapons would generally be contrary to the rules of international law applicable in armed conflict, but the court did not reach an opinion as to whether or not the threat or use would be lawful in specific extreme circumstances such as if
12012-408: The missiles before they land or implementing civil defense measures using early-warning systems to evacuate citizens to safe areas before an attack. Weapons designed to threaten large populations or to deter attacks are known as strategic weapons . Nuclear weapons for use on a battlefield in military situations are called tactical weapons . Critics of nuclear war strategy often suggest that
12144-422: The more abundant uranium-238 in a nuclear reactor , and separation from uranium could be by chemical means, as it was a different element, thereby avoiding the necessity for isotope separation. Kemmer suggested that since uranium was named after the planet Uranus , element 93 could be named neptunium and 94 plutonium after the next two planets. Later it was discovered that the Americans had independently adopted
12276-528: The order of 10 × 10 s (ten " shakes "). From 1 to 10 per cent of the fissile material would fission in this time; but even an atomic bomb with 1 per cent efficiency would release as much energy as 180,000 times its weight in TNT. The division of the MAUD Committee at Oxford was led by Simon. As a German émigré, he was only able to get involved after Peierls vouched for him, pointing out that Simon had already begun research on isotope separation, which would give
12408-443: The other laboratories. He examined the different processes by which they were obtaining isotopes. By the end of the summer in 1940, Peierls preferred gaseous diffusion to thermal diffusion. A paper was received from the United States in which George Kistiakowsky argued that a nuclear weapon would do very little damage, as most of the energy would be expended heating the surrounding air. A chemical explosive generates very hot gases in
12540-469: The possibility of a nuclear chain reaction in a paper published in Nature in April 1939. It was apparent to many scientists that, in theory at least, an extremely powerful explosive could be created, although most still considered an atomic bomb an impossibility. The term was already familiar to the British public through the writings of H. G. Wells , in his 1913 novel The World Set Free . In Britain,
12672-465: The problem by using the fast neutrons produced by fission, thus omitting consideration of a neutron moderator . He too believed the critical mass of a sphere of uranium to be "of the order of tons". However, Bohr had contended that the uranium-235 isotope was far more likely to capture neutrons and fission even from neutrons with the low energies produced by fission. Frisch began experimenting with uranium enrichment through thermal diffusion . Progress
12804-407: The project a head start by his participation. The Oxford team was mostly composed of non-British scientists, including Nicholas Kurti , Kurt Mendelssohn , Heinrich Kuhn , Henry Shull Arms and Heinz London . They concentrated on isotope separation with a method known as gaseous diffusion . This is based on Graham's law , which states that the rate of effusion of a gas through a porous barrier
12936-432: The project, only British-born scientists were considered. Even despite their early contributions, Peierls and Frisch were not allowed to participate in the MAUD Committee because, at a time of war, it was considered a security threat to have enemy aliens in charge of a sensitive project. In September 1940, the Technical Sub-Committee was formed, with Peierls and Frisch as members. However, Halban did not take his exclusion from
13068-409: The quote for a kilogram of uranium hexafluoride came to £5,000. Nonetheless, the order was placed in December 1940. ICI also explored methods of producing pure uranium metal. Peierls and his team worked on the theoretical problems of a nuclear bomb. In essence, they were in charge of finding out the technical features of the bomb. Along with Fuchs, Peierls also interpreted all the experimental data from
13200-428: The remains of the split atomic nuclei. Many fission products are either highly radioactive (but short-lived) or moderately radioactive (but long-lived), and as such, they are a serious form of radioactive contamination . Fission products are the principal radioactive component of nuclear fallout . Another source of radioactivity is the burst of free neutrons produced by the weapon. When they collide with other nuclei in
13332-408: The reports in his safe and had not shown them to members of his committee. I was amazed and distressed." Oliphant met with the S-1 Section. Samuel K. Allison was a new committee member, an experimental physicist and a protégé of Compton at the University of Chicago . Oliphant "came to a meeting", Allison recalled, "and said 'bomb' in no uncertain terms. He told us we must concentrate every effort on
13464-430: The requisite security clearance. Francis Perrin had defined a critical mass of uranium to be the smallest amount that could sustain a chain reaction, and had calculated it to be about 40 tonnes (39 long tons; 44 short tons). He reckoned that if a neutron reflector were placed around it, this might be reduced to 12 tonnes (12 long tons; 13 short tons). In a theoretical paper written in 1939, Peierls attempted to simplify
13596-460: The research culminated in two reports, "Use of Uranium for a Bomb" and "Use of Uranium as a Source of Power", known collectively as the MAUD Report. The report discussed the feasibility and necessity of an atomic bomb for the war effort. In response, the British created a nuclear weapons project, code named Tube Alloys . The MAUD Report was made available to the United States, where it energised
13728-422: The resulting critical mass was still only about eight kilograms. Meanwhile, Pryce investigated how long a runaway nuclear chain reaction in an atomic bomb would continue before it blew itself apart. He calculated that since the neutrons produced by fission have an energy of about 1 MeV (0.16 pJ) this corresponded to a speed of 1.4 × 10 cm/s . The major part of the chain reaction would be completed in
13860-492: The salaries of the universities' staff. However, Chadwick, Peierls, Simon and other professors, along with some research staff, were still paid out of university funds. The government also placed a £5,000 order for 5 kilograms (11 lb) of uranium hexafluoride with ICI. Uranium oxide was purchased from the Brandhurt Company, which sourced it from America. Wartime shortages impacted many areas of research, requiring
13992-415: The same names, following the same logic. Bretscher and Feather went further, theorising that irradiation of thorium could produce a new isotope of uranium, uranium-233 , which might also be susceptible to fission by both fast and slow neutrons. In addition to this work, Eric Rideal studied isotope separation through centrifugation . The division of the MAUD Committee at Birmingham was led by Peierls. He
14124-571: The separation of isotopes through thermal diffusion as was suggested in the Frisch–Peierls memorandum. This process was based on the fact that when a mixture of two gases passes through a temperature gradient, the heavier gas tends to concentrate at the cold end and the lighter gas at the warm end. That this can be used as a means of isotope separation was first demonstrated by Klaus Clusius and Gerhard Dickel in Germany in 1938, who used it to separate isotopes of neon . They used an apparatus called
14256-402: The surrounding material, the neutrons transmute those nuclei into other isotopes, altering their stability and making them radioactive. The most commonly used fissile materials for nuclear weapons applications have been uranium-235 and plutonium-239 . Less commonly used has been uranium-233 . Neptunium-237 and some isotopes of americium may be usable for nuclear explosives as well, but it
14388-498: The survival of the state were at stake. Another deterrence position is that nuclear proliferation can be desirable. In this case, it is argued that, unlike conventional weapons, nuclear weapons deter all-out war between states, and they succeeded in doing this during the Cold War between the U.S. and the Soviet Union . In the late 1950s and early 1960s, Gen. Pierre Marie Gallois of France, an adviser to Charles de Gaulle , argued in books like The Balance of Terror: Strategy for
14520-739: The two national projects. The Quebec Agreement established the Combined Policy Committee and the Combined Development Trust to co-ordinate their efforts. The 19 September 1944 Hyde Park Agreement extended both commercial and military co-operation into the post-war period. A British mission led by Akers assisted in the development of gaseous diffusion technology at the SAM Laboratories in New York. Another, headed by Oliphant, assisted with that of
14652-472: The universities and not the MAP, which was not allowed to employ enemy aliens. The MAP gradually came around to accepting their employment on the project. It protected some from internment , and provided security clearances. There were restrictions on where enemy aliens could work and live, and they were not allowed to own cars, so dispensations were required to allow them to visit other universities. "And so," wrote historian Margaret Gowing , "the greatest of all
14784-515: The uranium nucleus had been split. They published their finding in Nature in 1939. This phenomenon was a new type of nuclear disintegration, and was more powerful than any seen before. Frisch and Meitner calculated that the energy released by each disintegration was approximately 200 megaelectronvolts [MeV] (32 pJ). By analogy with the division of biological cells , they named the process " fission ". Niels Bohr and John A. Wheeler applied
14916-437: The wartime secrets was entrusted to scientists excluded for security reasons from other war work." The division of the MAUD Committee at Liverpool was led by Chadwick, who was assisted by Frisch, Rotblat, Gerry Pickavance , Maurice Pryce and John Riley Holt . The division at Liverpool also controlled a small team at the University of Bristol that included Alan Nunn May and Cecil Frank Powell . At Liverpool they focused on
15048-446: The weapon system and difficult to defend against the delivery of the weapon during a potential conflict. This can mean keeping weapon locations hidden, such as deploying them on submarines or land mobile transporter erector launchers whose locations are difficult to track, or it can mean protecting weapons by burying them in hardened missile silo bunkers. Other components of nuclear strategies included using missile defenses to destroy
15180-631: The world where there exists a single nuclear-weapon state. Aside from the public opinion that opposes proliferation in any form, there are two schools of thought on the matter: those, like Mearsheimer, who favored selective proliferation, and Waltz, who was somewhat more non- interventionist . Interest in proliferation and the stability-instability paradox that it generates continues to this day, with ongoing debate about indigenous Japanese and South Korean nuclear deterrent against North Korea . The threat of potentially suicidal terrorists possessing nuclear weapons (a form of nuclear terrorism ) complicates
15312-624: The yield comes from the final fissioning of depleted uranium. Virtually all thermonuclear weapons deployed today use the "two-stage" design described to the right, but it is possible to add additional fusion stages—each stage igniting a larger amount of fusion fuel in the next stage. This technique can be used to construct thermonuclear weapons of arbitrarily large yield. This is in contrast to fission bombs, which are limited in their explosive power due to criticality danger (premature nuclear chain reaction caused by too-large amounts of pre-assembled fissile fuel). The largest nuclear weapon ever detonated,
15444-531: Was John Cairncross , a member of the notorious Cambridge Five , who worked as the private secretary to Lord Hankey , a minister without portfolio in the War Cabinet . Cairncross provided the NKVD with information from the MAUD Committee. The United Kingdom did not have the manpower or resources of the United States, and despite its early and promising start, Tube Alloys fell behind its American counterpart and
15576-409: Was assisted by Haworth, Johnson and, from 28 May 1941, Klaus Fuchs . Haworth led the chemists in studying the properties of uranium hexafluoride. One thing in its favour was that fluorine has only one isotope, so any difference in weight between two molecules is solely due to the different isotope of uranium. Otherwise, uranium hexafluoride was far from ideal. It solidified at 120 °F (49 °C),
15708-585: Was complete and wholehearted. In response to the 1939 Einstein-Szilard letter , President Franklin D. Roosevelt had created an Advisory Committee on Uranium in October 1939, chaired by Lyman Briggs . Research concentrated on slow fission for power production, but with a growing interest in isotope separation. In June 1941, Roosevelt created the Office of Scientific Research and Development (OSRD), with Vannevar Bush as its director, personally responsible to
15840-447: Was corrosive, and reacted with many substances, including water. It was therefore difficult and dangerous to handle. However, a search by the chemists at Birmingham failed to uncover another gaseous compound of uranium. Lindemann used his influence with Lord Melchett , a director of ICI, to get ICI to produce uranium hexafluoride on an industrial scale. ICI's hydrofluoric acid plant was out of commission, and required extensive repairs, so
15972-619: Was dwarfed by it. The British considered producing an atomic bomb without American help, but the project would have needed overwhelming priority, the projected cost was staggering, disruption to other wartime projects was inevitable, and it was unlikely to be ready in time to affect the outcome of the war in Europe . At the Quebec Conference in August 1943, Churchill and Roosevelt signed the Quebec Agreement , which merged
16104-514: Was estimated to cost £5 million and would require a large skilled labour force that was also needed for other parts of the war effort. It could be available in as little as two years. The amount of damage that it would do was estimated to be similar to that of the Halifax explosion in 1917, which had devastated everything in a 1 / 4 -mile (0.40 km) radius. The report warned that Germany had shown interest in heavy water, and although this
16236-416: Was fairly long-lived. That a letter on such a sensitive subject could still be published irked Chadwick, and he asked for an official protest to be sent to the Americans, which was done. Bretscher and Feather argued, on theoretical grounds, that this element might be capable of fission by both fast and slow neutrons like uranium-235. If so, this promised another path to an atomic bomb, as it could be bred from
16368-467: Was formally constituted by CSSAW. CSSAW was abolished in June 1940, and the MAUD Committee then came directly under the MAP. Thomson chaired the committee, and initially acted as its secretary as well, writing up the minutes in longhand on foolscap, until the MAP provided a secretary. At first the new committee was named the Thomson Committee after its chairman, but this was soon exchanged for
16500-621: Was kept small and included only one representative from each university laboratory. Its members were: Blackett, Chadwick, Cockcroft, Ellis, Haworth, Franz Simon , Thomson and the Director of Scientific Research at the MAP. The MAUD Technical Committee's members were: Moses Blackman , Egon Bretscher , Norman Feather , Frisch, Halban, C. H. Johnson , Kowarski, Wilfrid Mann , Moon, Nevill Mott , Oliphant, Peierls and Thomson. Its meetings were normally attended by Winston Churchill 's scientific advisor, Frederick Lindemann , or his representative, and
16632-679: Was not considered useful for a bomb, the possibility remained that Germany could also be working on the bomb. The second report was shorter. It recommended that Halban and Kowarski should move to the US where there were plans to make heavy water on a large scale. Plutonium might be more suitable than uranium-235, and plutonium research should continue in Britain. It concluded that the controlled fission of uranium could be used to generate heat energy for use in machines, and provide large quantities of radioisotopes which could be used as substitutes for radium . Heavy water or possibly graphite might serve as
16764-564: Was paid for out of the universities' funds. Only in September 1940 did government funding become available. The MAP signed contracts that gave £3,000 to the Cavendish Laboratory at Cambridge (later increased to £6,500), £1,000 (later increased to £2,000) to the Clarendon Laboratory at Oxford, £1,500 to Birmingham, and £2,000 to Liverpool. The universities were reimbursed for expenses by the MAP, which also began to pay some of
16896-700: Was sceptical of the likelihood of an atomic bomb being developed, reckoning the odds of success at 100,000 to 1. Even at such long odds, the danger was sufficiently great to be taken seriously. Lord Chartfield , the Minister for Coordination of Defence , checked with the Treasury and Foreign Office , and found that the Belgian Congo uranium was owned by the Union Minière du Haut Katanga company. Its British vice-president, Lord Stonehaven , arranged
17028-436: Was slow; the required equipment was not available, and the radar project had first call on the available resources. He wondered what would happen if he was able to produce a sphere of pure uranium-235. When he used Peierls' formula to calculate its critical mass, he received a startling answer: less than a kilogram would be required. Frisch and Peierls produced the Frisch–Peierls memorandum in March 1940. In it they reported that
17160-670: Was the Belgian Congo , and they were worried that it could fall into German hands. Unsure as to how to go about this, they spoke to Sir William Spens , the master of Corpus Christi College, Cambridge . In April 1939, he approached Sir Kenneth Pickthorn , the local Member of Parliament , who took their concerns to the Secretary of the Committee for Imperial Defence , Major General Hastings Ismay . Ismay in turn asked Sir Henry Tizard for an opinion. Like many scientists, Tizard
17292-744: Was the Special Atomic Demolition Munition , or SADM, sometimes popularly known as a suitcase nuke . This is a nuclear bomb that is man-portable, or at least truck-portable, and though of a relatively small yield (one or two kilotons) is sufficient to destroy important tactical targets such as bridges, dams, tunnels, important military or commercial installations, etc. either behind enemy lines or pre-emptively on friendly territory soon to be overtaken by invading enemy forces. These weapons require plutonium fuel and are particularly "dirty". They also demand especially stringent security precautions in their storage and deployment. Small "tactical" nuclear weapons were deployed for use as antiaircraft weapons. Examples include
17424-473: Was to replace the "y" with an "i", producing 'radium taken'. When Bohr returned to England in 1943, it was discovered that the message was addressed to John Cockcroft and Bohr's housekeeper Maud Ray, who was from Kent. Thus the committee was named the MAUD Committee. Although the initials stood for nothing, it was officially the MAUD Committee, not the Maud Committee. Because of the top secret aspect of
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