The Hydrogen Bomb

Nuclear weapons where the explosion is caused by the fusion of hydrogen isotopes are called thermonuclear weapons (hydrogen bombs). In order to reach the ignition temperature of 100 000 000°C, a number of uranium bombs are used. The explosion can maintain the required temperature only for a millionth part of a second. Since deuterium and tritium are gaseous at a normal temperature, the density of the particles is too low to induce enough collisions, and therefore fusions, within this short period of time. As a result, the isotopes are liquefied at -250°C to obtain a sufficient particle density ('refrigerator bomb').

The destructive power of an H-bomb can be increased tremendously by surrounding the load with a layer of U 238. This kind of bomb is called three phase FFF*-bomb.

The bomb has three stages:
1. Ignition of the fission bomb ð high temperatures are caused ð
2. Fusion ð quickly releases (energy-rich) neutrons, which cause ð
3. Fission of U 238 ð enormous energy

*Fission - Fusion - Fission