Question: How many existing basic design types are there of the weapons the United States and the Soviet Union had an arms race over?

full_context: Document 1: Culture during the Cold War: The Cold War (1947–91) was reflected in culture through music, movies, books, television and other media, as well as sports and social beliefs and behavior. One major element of the Cold War was the threat of a nuclear war; another was espionage. Many works use the Cold War as a backdrop, or directly take part in fictional conflict between the United States and the Soviet Union The period 1953–62 saw Cold War themes first enter the mainstream culture as a public preoccupation. For the historical context in America see United States in the 1950s.
Document 2: Nuclear arms race: The nuclear arms race was a competition for supremacy in nuclear warfare between the United States, the Soviet Union, and their respective allies during the Cold War. During this period, in addition to the American and Soviet nuclear stockpiles, other countries developed nuclear weapons, though none engaged in warhead production on nearly the same scale as the two superpowers.
Document 3: Thermonuclear weapon: A thermonuclear weapon is a second-generation nuclear weapon design using a secondary nuclear fusion stage consisting of implosion tamper, fusion fuel, and sparkplug which is bombarded by the energy released by the detonation of a primary fission bomb within, compressing the fuel material (tritium, deuterium or lithium deuteride) and causing a fusion reaction. Some advanced designs use fast neutrons produced by this second stage to ignite a third fast fission or fusion stage. The fission bomb and fusion fuel are placed near each other in a special radiation-reflecting container called a radiation case that is designed to contain x-rays for as long as possible. The result is greatly increased explosive power when compared to single-stage fission weapons. The device is colloquially referred to as a hydrogen bomb or, an H-bomb, because it employs the fusion of isotopes of hydrogen.
Document 4: Soviet influence on the peace movement: During the Cold War (1947–1991), when the Soviet Union and the United States were engaged in an arms race, the Soviet Union promoted its foreign policy through the World Peace Council and other front organizations. Some writers have claimed that it also influenced non-aligned peace groups in the West, although the CIA and MI5 have doubted the extent of Soviet influence.
Document 5: List of nuclear weapons tests of the Soviet Union: The nuclear weapons tests of the Soviet Union were performed between 1949 and 1990 as part of the nuclear arms race. The Soviet Union conducted 715 nuclear tests using 969 total devices by official count, including 219 atmospheric, underwater, and space tests and 124 peaceful use tests. Most of the tests took place at the Southern Test Site in Semipalatinsk, Kazakhstan and the Northern Test Site at Novaya Zemlya. Other tests took place at various locations within the Soviet Union, including now-independent Kazakhstan, Uzbekistan, Ukraine and Turkmenistan.
Document 6: Cold War II: Cold War II (also called the New Cold War, Second Cold War and Cold War 2.0) refers to a renewed state of political and military tension between opposing geopolitical power-blocs, with one bloc typically reported as being led by Russia and/or China, and the other led by the United States or NATO. This is akin to the original Cold War that saw a global confrontation between the Western Bloc led by the United States and the Eastern Bloc led by the Soviet Union, Russia's predecessor state. American political scientist Robert Legvold posits that the "new Cold War began the moment we went over the cliff, and that happened with the Ukraine crisis." Others, such as Andrew C. Kuchins in 2016, believe that the term is "unsuited to the present conflict," but the situation is arguably more dangerous than during the original Cold War. One of the primary features of the "New Cold War", as first defined by Philip N. Howard, is that conflict is experienced primarily over and through broadcast media, social media, and information infrastructure.
Document 7: Salted bomb: A salted bomb is a nuclear weapon designed to function as a radiological weapon, producing enhanced quantities of radioactive fallout, rendering a large area uninhabitable. The term is derived both from the means of their manufacture, which involves the incorporation of additional elements to a standard atomic weapon, and from the expression "to salt the earth", meaning to render an area uninhabitable for generations. The idea originated with Hungarian-American physicist Leo Szilard, in February 1950. His intent was not to propose that such a weapon be built, but to show that nuclear weapon technology would soon reach the point where it could end human life on Earth. No intentionally salted bomb has ever been atmospherically tested, however the UK tested a 1 kiloton bomb incorporating a small amount of cobalt as an experimental radiochemical tracer at their Tadje testing site in Maralinga range, Australia, on September 14, 1957. Furthermore the triple "taiga" nuclear salvo test, as part of the preliminary March 1971 Pechora–Kama Canal project, produced substantial amounts of Co-60, with this fusion generated neutron activation product being responsible for about half of the gamma dose now (2011) at the test site.
Document 8: Nuclear weapons testing: Nuclear weapons tests are experiments carried out to determine the effectiveness, yield, and explosive capability of nuclear weapons. Throughout the twentieth century, most nations that developed nuclear weapons tested them. Testing nuclear weapons can yield information about how the weapons work, as well as how the weapons behave under various conditions and how personnel, structures, and equipment behave when subjected to nuclear explosions. Nuclear testing has often been used as an indicator of scientific and military strength, and many tests have been overtly political in their intention; most nuclear weapons states publicly declared their nuclear status by means of a nuclear test.
Document 9: United States and weapons of mass destruction: The United States is known to have possessed three types of weapons of mass destruction: nuclear weapons, chemical weapons, and biological weapons. The U.S. is the only country to have used nuclear weapons in combat, when it detonated two atomic bombs over the Japanese cities of Hiroshima and Nagasaki during World War II. It had secretly developed the earliest form of the atomic weapon during the 1940s under the title "Manhattan Project". The United States pioneered the development of both the nuclear fission and hydrogen bombs (the latter involving nuclear fusion). It was the world's first and only nuclear power for four years (1945–1949), until the Soviet Union managed to produce its own nuclear weapon. The United States has the second largest number of deployed nuclear weapons in the world, after Russia.
Document 10: Nuclear weapon: A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission bomb) or from a combination of fission and fusion reactions (thermonuclear bomb). 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 tonTNT . The first thermonuclear ("hydrogen") bomb test released energy approximately equal to 10 e6tonTNT . A thermonuclear weapon weighing little more than 2400 lb can release energy equal to more than 1.2 e6tonTNT . A nuclear device no larger than traditional bombs 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.
Document 11: Nuclear weapon design: Nuclear weapon designs are physical, chemical, and engineering arrangements that cause the physics package of a nuclear weapon to detonate. There are three existing basic design types. In many existing designs, the explosive energy of deployed devices is derived primarily from nuclear fission, not fusion. (This includes fission of any U-238 tamper or casing due to fusion produced neutrons.)
Document 12: Pakistan and weapons of mass destruction: Pakistan is one of nine states to possess nuclear weapons, and the only Muslim majority country to do so. Pakistan began development of nuclear weapons in January 1972 under Prime Minister Zulfikar Ali Bhutto, who delegated the program to the Chairman of the Pakistan Atomic Energy Commission (PAEC) Munir Ahmad Khan with a commitment to having the bomb ready by the end of 1976. Since PAEC, consisting of over twenty laboratories and projects under nuclear engineer Munir Ahmad Khan, was falling behind schedule and having considerable difficulty producing fissile material, Abdul Qadeer Khan was brought from Europe by Bhutto at the end of 1974. As pointed out by Houston Wood, Professor of Mechanical & Aerospace Engineering, University of Virginia, Charlottesville, in his article on gas centrifuges, "The most difficult step in building a nuclear weapon is the production of fissile material"; as such, this work in producing fissile material as head of the Kahuta Project was pivotal to Pakistan developing the capability to detonate a nuclear bomb by the end of 1984.
Document 13: Nuclear proliferation: Nuclear proliferation is the spread of nuclear weapons, fissionable material, and weapons-applicable nuclear technology and information to nations not recognized as "Nuclear Weapon States" by the Treaty on the Non-Proliferation of Nuclear Weapons, commonly known as the Non-Proliferation Treaty or NPT. Proliferation has been opposed by many nations with and without nuclear weapons, the governments of which fear that more countries with nuclear weapons may increase the possibility of nuclear warfare (up to and including the so-called "countervalue" targeting of civilians with nuclear weapons), de-stabilize international or regional relations, or infringe upon the national sovereignty of states.
Document 14: Aftermath of World War II: The aftermath of World War II was the beginning of an era defined by the decline of the old great powers and the rise of two superpowers: the Soviet Union (USSR) and the United States of America (USA). Allied during World War II, the USA and the USSR became competitors on the world stage and engaged in the Cold War, so called because it never resulted in overt, declared hot war between the two powers but was instead characterized by espionage, political subversion and proxy wars. Western Europe and Japan were rebuilt through the American Marshall Plan whereas Eastern Europe fell under the Soviet sphere of influence and eventually an "Iron Curtain". Europe was divided into a US-led Western Bloc and a Soviet-led Eastern Bloc. Internationally, alliances with the two blocs gradually shifted, with some nations trying to stay out of the Cold War through the Non-Aligned Movement. The Cold War also saw a nuclear arms race between the two superpowers; part of the reason that the Cold War never became a "hot" war was that the Soviet Union and the United States had nuclear deterrents against each other, leading to a mutually assured destruction standoff.
Document 15: Timeline of nuclear weapons development: This timeline of nuclear weapons development is a chronological catalog of the evolution of nuclear weapons rooting from the development of the science surrounding nuclear fission and nuclear fusion. In addition to the scientific advancements, this timeline also includes several political events relating to the development of nuclear weapons. The availability of intelligence on recent advancements in nuclear weapons of several major countries (such as United States and the Soviet Union) is limited because of the classification of technical knowledge of nuclear weapons development.
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