Mark 4 nuclear bomb

Mark 4 nuclear bomb
A Mark 4N riveted aluminum bomb casing. Stockpile Mk 4s used a 2,830 lb (1,280 kg) steel casing.[1]
Type	Air-dropped Nuclear fission weapon
Place of origin	United States
Service history
In service	1949–1953
Used by	United States Air Force (USAF)
Production history
No. built	About 550
Specifications
Mass	10,800 to 10,900 pounds (4,900 to 4,940 kg)
Length	128 in (3,300 mm)
Diameter	60 in (1,500 mm)
Crew	1x Weaponeer for pit insertion and arming
Filling	Composite uranium and plutonium fissile pits
Detonation mechanism	focused high explosive implosion
Blast yield	1, 3.5, 8, 14, 21, 22, 31 kt (4.2, 14.6, 33.5, 58.6, 87.9, 92.0, 129.7 TJ), depending on construction and/or pit

The Mark 4 nuclear bomb was an American implosion-type nuclear bomb based on the earlier Mark 3 Fat Man design, used in the Trinity test and the bombing of Nagasaki. With the Mark 3 needing each individual component to be hand-assembled by only highly trained technicians under closely controlled conditions, the purpose of the Mark 4 was to produce an atomic weapon as a practical piece of ordnance. The Mark 4 Mod 0 entered the stockpile starting March 19, 1949^[2] and was in use until 1953. With over 500 units procured, the Mark 4 was the first mass-produced nuclear weapon.