Nuclear test in the context of Mushroom cloud

Carbon-14, C-14, C or radiocarbon, is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons. Its presence in organic matter is the basis of the radiocarbon dating method pioneered by Willard Libby and colleagues (1949) to date archaeological, geological and hydrogeological samples. Carbon-14 was discovered on February 27, 1940, by Martin Kamen and Sam Ruben at the University of California Radiation Laboratory in Berkeley, California. Its existence had been suggested by Franz Kurie in 1934.

There are three naturally occurring isotopes of carbon on Earth: carbon-12 (C), which makes up 99% of all carbon on Earth; carbon-13 (C), which makes up 1%; and carbon-14 (C), which occurs in trace amounts, making up about 1.2 atoms per 10 atoms of carbon in the atmosphere. C and C are both stable; C is unstable, with half-life 5700±30 years, decaying into nitrogen-14 (
N) through beta decay. Pure carbon-14 would have a specific activity of 62.4 mCi/mmol (2.31 GBq/mmol), or 164.9 GBq/g. The primary natural source of carbon-14 on Earth is cosmic ray action on nitrogen in the atmosphere, and it is therefore a cosmogenic nuclide. Open-air nuclear testing between 1955 and 1980 contributed to this pool, however.

Operation Castle was a United States series of high-yield (high-energy) nuclear tests by Joint Task Force 7 (JTF-7) at Bikini Atoll beginning in March 1954. It followed Operation Upshot–Knothole and preceded Operation Teapot.

Conducted as a joint venture between the Atomic Energy Commission (AEC) and the Department of Defense (DoD), the ultimate objective of the operation was to test designs for an aircraft-deliverable thermonuclear weapon. All the devices tested, which ranged in weight from 6,520 to 39,600 pounds (2,960 to 17,960 kg), were built to be dropped from aircraft. However, ballistic casings, fins and fusing systems would have to be attached.

Hao, or Haorangi, is a large coral atoll in the central part of the Tuamotu Archipelago. It has c. 1000 people living on 35 km (14 sq mi). It was used to house the military support base for the nuclear tests on Mururoa. Because of its shape, French explorer Louis Antoine de Bougainville named it "Île de la Harpe" (Harp Island).

639 was the codename for China's first full-scale test of a two-staged thermonuclear device, on 17 June 1967, yielding 3.3 megatons of TNT. It followed the first two-stage thermonuclear test, at a smaller 122 kt yield, in December 1966. It was the sixth nuclear test that was carried out by the People's Republic of China, and represented the completion of the "second bomb" i.e. thermonuclear bomb component of the "Two Bombs, One Satellite" program. With these two tests, China became the fourth nation to develop thermonuclear weapons, following the US, USSR, and UK. Taking place 32 months after the first Chinese nuclear test, Project 596, it remains the fastest progression from nuclear to full thermonuclear test of any country.

Operation Teapot was a series of 14 nuclear test explosions conducted at the Nevada Test Site in the first half of 1955. It was preceded by Operation Castle, and followed by Operation Wigwam. Wigwam was, administratively, a part of Teapot, but it is usually treated as a class of its own. The aims of the operation were to establish military tactics for ground forces on a nuclear battlefield and to improve the nuclear weapons used for strategic delivery.

The Enola Gay (/əˈnoʊlə/) is a Boeing B-29 Superfortress bomber, named after Enola Gay Tibbets, the mother of the pilot, Colonel Paul Tibbets. On 6 August 1945, during the final stages of World War II, it became the first aircraft to drop an atomic bomb in warfare. The bomb, code-named "Little Boy", was targeted at the city of Hiroshima, Japan, and destroyed about three-quarters of the city. Enola Gay participated in the second nuclear attack as the weather reconnaissance aircraft for the primary target of Kokura. Clouds and drifting smoke resulted in Nagasaki, a secondary target, being bombed instead.

After the war, the Enola Gay returned to the United States, where it was operated from Roswell Army Air Field, New Mexico. In May 1946, it was flown to Kwajalein for the Operation Crossroads nuclear tests in the Pacific, but was not chosen to make the test drop at Bikini Atoll. Later that year, it was transferred to the Smithsonian Institution and spent many years parked at air bases exposed to the weather and souvenir hunters, before its 1961 disassembly and storage at a Smithsonian facility in Suitland, Maryland.

Chagai-II is the codename assigned to the second atomic test conducted by Pakistan, carried out on 30 May 1998 in the Kharan Desert in Balochistan Province of Pakistan. Chagai-II took place two days after Pakistan's first successful test, Chagai-I, which was carried out on 28 May 1998 in the Ras Koh area in Chagai District, Balochistan, Pakistan.

The initial goals were to test the new designs of the weapon rather than studying the effects, and were different from the first tests in that they were primarily conducted by the Pakistan Atomic Energy Commission (PAEC), with the Pakistan Armed Forces engineering formations having only a supporting role.

On 9 October 2006, North Korea performed its first nuclear test, detonating a plutonium-based device underground.

On 3 October 2006, North Korea announced its intention to conduct a nuclear test. The blast is generally estimated to have had an explosive force of less than one kiloton, and some radioactive output was detected. United States officials suggested the device may have been a nuclear explosive that misfired.

Operation Ivy was the eighth series of American nuclear tests, coming after Tumbler-Snapper and before Upshot–Knothole. The two explosions were staged in late 1952 at Enewetak Atoll in the Pacific Proving Ground in the Marshall Islands.