Radiation Implosion - Radiation Transport

Radiation Transport

In a Teller-Ulam bomb, the object to be imploded is called the "secondary". It contains fusion material, such as lithium deuteride, and its outer layers are a material which is opaque to x-rays, such as lead or uranium-238.

In order to get the x-rays from the surface of the primary, the fission bomb, to the surface of the secondary, a system of "x-ray reflectors" is used.

The reflector is typically a cylinder made of a material such as uranium. The primary is located at one end of the cylinder and the secondary is located at the other end. The interior of the cylinder is commonly filled with a foam which is mostly transparent to x-rays, such as polystyrene.

The term reflector is misleading, since it gives the reader an idea that the device works like a mirror. Some of the x-rays are diffused or scattered, but the majority of the energy transport happens by a two-step process: the x-ray reflector is heated to a high temperature by the flux from the primary, and then it emits x-rays which travel to the secondary. Various classified methods are used to improve the performance of the reflection process.

Some Chinese documents showed that Chinese scientists used a different method to make radiation implosion. According to these documents, X-ray lens but not reflector should be used to transfer the energy from primary to secondary during the making of the first Chinese H-Bomb. Most of these Chinese documents are in Chinese language.