Little Boy

Little Boy
Little boy.jpg
A post-war Little Boy model
TypeNuclear weapon
Place of originUnited States
Production history
DesignerLos Alamos Laboratory
Produced1945
No. built26
Specifications
Weight9,700 pounds (4,400 kg)
Length10 feet (3.0 m)
Diameter28 inches (71 cm)

FillingUranium-235
Filling weight140 lb (64 kg)
Blast yield15 kilotons of TNT (63 TJ)

"Little Boy" was the code name for the type of nuclear bomb dropped on the Japanese city of Hiroshima on 6 August 1945 during World War II. It was the first nuclear weapon used in warfare. The bomb was dropped by the Boeing B-29 Superfortress Enola Gay piloted by Colonel Paul W. Tibbets, Jr., commander of the 509th Composite Group of the United States Army Air Forces. It exploded with an energy of approximately 15 kilotons of TNT (63 TJ) and caused widespread death and destruction throughout the city. The Hiroshima bombing was the second nuclear explosion in history, after the Trinity test, and the first uranium-based detonation.

Little Boy was developed by Lieutenant Commander Francis Birch's group at the Manhattan Project's Los Alamos Laboratory during World War II, a development of the unsuccessful Thin Man nuclear bomb. Like Thin Man, it was a gun-type fission weapon, but it derived its explosive power from the nuclear fission of uranium-235, whereas Thin Man was based on fission of plutonium-239. Fission was accomplished by shooting a hollow cylinder of enriched uranium (the "bullet") onto a solid cylinder of the same material (the "target") by means of a charge of nitrocellulose propellant powder. It contained 64 kg (141 lb) of enriched uranium, although less than a kilogram underwent nuclear fission. Its components were fabricated at three different plants so that no one would have a copy of the complete design.

After the war ended, it was not expected that the inefficient Little Boy design would ever again be required, and many plans and diagrams were destroyed. However, by mid-1946, the Hanford Site reactors began suffering badly from the Wigner effect, the dislocation of atoms in a solid caused by neutron radiation, and plutonium became scarce, so six Little Boy assemblies were produced at Sandia Base. The Navy Bureau of Ordnance built another 25 Little Boy assemblies in 1947 for use by the Lockheed P2V Neptune nuclear strike aircraft which could be launched from the Midway-class aircraft carriers. All the Little Boy units were withdrawn from service by the end of January 1951.

Naming

Physicist Robert Serber named the first two atomic bomb designs during World War II based on their shapes: Thin Man and Fat Man. The "Thin Man" was a long, thin device and its name came from the Dashiell Hammett detective novel and series of movies about The Thin Man. The "Fat Man" was round and fat so it was named after Kasper Gutman, a rotund character in Hammett's novel The Maltese Falcon, played by Sydney Greenstreet in the film version. Little Boy was named by others as an allusion to Thin Man, since it was based on its design.[1]

Other Languages
Afrikaans: Little Boy
asturianu: Little Boy
বাংলা: লিটল বয়
Bikol Central: Little Boy
български: Малчугана
català: Little Boy
čeština: Little Boy
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euskara: Little Boy
فارسی: پسر کوچک
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galego: Little Boy
한국어: 리틀 보이
हिन्दी: लिटिल बॉय
hrvatski: Little Boy
Bahasa Indonesia: Little Boy
italiano: Little Boy
עברית: ילד קטן
kurdî: Little Boy
latviešu: Mazais zēns
Lëtzebuergesch: Little Boy
lietuvių: Mažylis (bomba)
magyar: Little Boy
मैथिली: लिटिल बोय
मराठी: लिटल बॉय
Nederlands: Little Boy
norsk: Little Boy
norsk nynorsk: Little Boy
ਪੰਜਾਬੀ: ਲਿਟਲ ਬੁਆਏ
پنجابی: لٹل بوائے
polski: Little Boy
português: Little Boy
română: Little Boy
русский: Малыш (бомба)
Scots: Little Boy
Simple English: Little Boy
slovenčina: Little Boy
slovenščina: Deček (bomba)
српски / srpski: Малиша (бомба)
suomi: Little Boy
svenska: Little Boy
Tagalog: Little Boy
Türkçe: Little Boy
українська: Малюк (бомба)
Tiếng Việt: Little Boy
粵語: Little Boy