Gun-Type! Implosion-Type! Nuclear Bomb Miniaturization! [Thin Man] [Fat Man] [Little Boy]!

The basic principle of an atomic bomb was very simple.

As long as the mass of Uranium-235 exceeded the critical mass, the "ignition" neutron source could release neutrons and trigger a chain reaction.

Based on this principle, the many bigwigs in the theoretical division of Los Alamos Laboratory quickly came up with a simple design.

This design was named the [Gun-Type], a straightforward and brutal form of physical assembly.

Gun-type atomic bombs were generally long, narrow cylinders, with an overall structure very similar to an artillery shell.

The core principle of the gun-type design was:

"Using the shockwave produced by high explosives to join two subcritical masses of nuclear material together within milliseconds."

"Then, at the instant they merge, activate the ignition neutron source, release neutrons, and trigger a chain reaction."

In a gun-type atomic bomb, the two pieces of nuclear material were placed at opposite ends of a steel tube, with high explosives installed behind the nuclear material at the rear.

Once detonated, the shockwave drove the rear nuclear material into the forward nuclear material at a speed of 300 m/s, triggering the explosion.

This method resembled the way gunpowder propelled an ordinary firearm, hence the name "gun-type." It was also called the "bullet method."

The advantage of this method was its extremely simple structure and low technical threshold. It could even be manufactured without complex nuclear testing.

However, the shortcomings of gun-type atomic bombs were also obvious.

First, their power had an upper limit.

The nuclear material at both the front and rear ends had to remain below critical mass.

In other words, the total mass of nuclear material in the atomic bomb could be no more than twice the critical mass. Its ceiling was locked in place.

Second, the material utilization rate was extremely low.

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