Little Boy ( English Little Boy literally "little boy") is the code name for the atomic ( uranium ) bomb developed as part of the Manhattan project . The first successfully detonated uranium bomb and the first ever atomic bomb , which was used as a weapon and was dropped by the United States on August 6, 1945 on the Japanese city of Hiroshima .
| "Kid" | |
|---|---|
 Model of the bomb "Baby" dropped on Hiroshima | |
| Type of | atomic bomb |
| A country |  USA |
| Production history | |
| Constructor | Los Alamos National Laboratory |
| Manufacturer | National Security Center Y-12 , Tennessee Eastman Company |
| Specifications | |
| Weight kg | 4400 |
| Length mm | 3000 |
| Diameter mm | 700 |
| Blast power | from 13 to 18 kilotons of TNT |
Content
Design
The weight of the bomb was 4.4 tons, a size of 3 meters in length, 71 centimeters in diameter. Uranium for its filling was extracted in the Belgian Congo (now the Democratic Republic of the Congo ), in Canada ( Big Bear Lake ) and in the United States ( Colorado ).
Unlike most modern bombs made by the implosive principle , "Baby" was a cannon-type bomb . The cannon bomb is easy to calculate and manufacture, practically knows no failures (therefore, the exact drawings of the bomb are still classified ). The flip side of this design is low efficiency .
Nuclear fuel has a critical mass : a subcritical amount of uranium is simply radioactive, a supercritical amount explodes (this is due to the huge release of energy during a chain reaction ). The chain reaction in the fuel of critical mass can begin spontaneously, but in the "Baby" uses a neutron flux, which causes the initial fission of nuclei. Then, upon fission, the nuclei themselves release neutrons, thereby causing a new chain of reactions. With a weak neutron flux and poor "sealing" the mass quickly becomes non-critical and the chain reaction ends. It is necessary to quickly bring the fuel to a supercritical state and keep it in this state for as long as possible, preventing it from scattering ahead of time. In Malysh, this problem is solved as follows: the main part of the bomb is the cut-off barrel of the naval gun, at the muzzle end of which there is a target in the form of a uranium cylinder and beryllium is the polonium initiator. In the breech of the barrel - cordite gunpowder and a tungsten carbide shell . A uranium pipe is attached to the head of the projectile. A shot from such a “gun” connects the pipe and cylinder, so that they form a supercritical mass. At the same time, the initiator is compressed, the neutron flux from it multiplies, and a nuclear explosion begins; the strength of the barrel and the pressure of the powder gases hold the uranium parts.
The bomb contained 64 kilograms of extremely expensive highly enriched uranium, of which about 700 grams, or just over 1%, were directly involved in the nuclear chain reaction . The mass defect during a nuclear reaction was about 600 milligrams, that is, according to Einstein’s formula 600 milligrams of mass turned into energy equivalent to the energy of the explosion (according to various estimates) from 13 to 18 thousand tons of TNT .
A 16.4 cm long naval gun barrel was used shortened to 1.8 m, while the uranium “target” was a cylinder with a diameter of 100 mm and a mass of 25.6 kg, upon which a cylindrical “bullet” with a mass of 38 5 kg with the corresponding internal channel. Such an “intuitively incomprehensible” design was made to reduce the neutron background of the target: it was not close to it, but at a distance of 59 mm from the neutron reflector (“tamper”). As a result, the risk of premature onset of the fission chain reaction with incomplete energy release was reduced to a few percent.
Despite the low efficiency , the radioactive contamination from the explosion was small, since the explosion was carried out 600 m above the ground, and unreacted uranium itself is weakly radioactive in comparison with the products of a nuclear reaction. Fuses were inserted into this bomb directly in the aircraft, in the bomb bay, 15 minutes after take-off in order to minimize the risk of the consequences of an unsuccessful take-off. At the same time, it was likely that it might work abnormally.
See also
- Fat man (bomb)
- Trinity (test)
Literature
- Bernstein, Jeremy. Nuclear Weapons: What You Need to Know. - Cambridge University Press, 2007. - ISBN 0-521-88408-X .
- Campbell, Richard H. The Silverplate Bombers: A History and Registry of the Enola Gay and Other B-29s Configured to Carry Atomic Bombs. - Jefferson, North Carolina: McFarland & Company, 2005 .-- ISBN 0-7864-2139-8 .
- Coster-Mullen, John. Atom Bombs: The Top Secret Inside Story of Little Boy and Fat Man. - Waukesha, Wisconsin: J. Coster-Mullen, 2012.
- Diacon, Diane. Residential Housing and Nuclear Attack . - London: Croom Helm, 1984. - ISBN 978-0-7099-0868-5 .
- United States Strategic Bombing Survey, Summary Report (Pacific War) . - Washington: United States Government Printing Office, 1946.
Links
- First Generation Nuclear Bombs: “Baby” and “Fat Man”
- Definition and explanation of Little Boy
- Hiroshima & Nagasaki Remembered information about preparation and dropping the Little Boy bomb
- The Atomic Bombings of Hiroshima and Nagasaki . The Manhattan Engineer District (29 Jun 1946). Date of treatment November 6, 2013. Archived on April 6, 2012.
- Genetic Effects: Question # 7 . Radiation Effects Research Foundation. Date of treatment November 6, 2013.