Implosion-Type Bomb

One of the methods for quickly producing a super-critical mass of plutonium for a nuclear explosion is to fashion a sub-critical mass of Pu-239 in a spherical shape and then set off high explosives to drive it inward. A spherical shell of high-explosive material is made up of fitting pieces (called "lenses" to focus the explosion inward) which are wired with detonators to set them off simultaneously. This creates enough force to increase the density of the sphere of plutonium to the point where it is super-critical. This implosion technique was used in the first plutonium bomb test at Alamogordo and in the Nagasaki bomb, each with an explosive power of about 20 kilotons of TNT. The chain reaction lasts about a microsecond.

快速产生用于核爆炸的超临界钚量的一种方法是，先制造一个球形的亚临界钚-239量，然后引爆高能炸药使其向内压缩。由多个拼接部件（称为“透镜”，用于聚焦爆炸向内）组成的高能炸药壳体，通过引信同时引爆。这会产生足够的力，使钚球的密度增加到超临界水平。这种内爆技术被用于第一次钚弹试验和广岛原子弹，每颗炸弹的爆炸当量约为20千吨TNT。链式反应持续约微秒。

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Nuclear weapon concepts

Nuclear energy concepts

Fission concepts

索引核武器概念核能概念裂变概念

HyperPhysics***** Nuclear

HyperPhysics ***** 核物理

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Gun-Type Nuclear Detonations

枪型核爆

When one sub-critical mass of a fissile material is held in place and another sub-critical mass is fired into it with the use of high explosives such that the assembly is then super-critical, this is called a gun-type nuclear device. This kind of device was used to construct the Hiroshima bomb. The explosive must force the additional mass into contact so that it maintains contact for about a microsecond, the time it takes for the rapid chain reaction to produce the nuclear explosion. The explosive mass is held in place partly by a heavy, solid surrounding shell called a tamper.