User:Howard C. Berkowitz/Boost

Tritium boosting (more correctly deuterium-tritium boosting) is a technique for increasing aspects of the efficiency of fission devices. It is not a full fusion reaction, although a tritium-boosted fission Primary will be more effective in initiating a fusion Secondary. While boosting itself produces only a slight additional amount of blast, it has a major effect on the neutrons produced by the Primary, and indeed may increase explosive yield of other parts of the Primary.

Tritium boosting, which in practice consists of imploding thin hollow fissilematerial spheres containing DT gas, is relatively easy to implement. This is because the highexplosive technique required for that purpose is the same as the one used for imploding metallic liners in antitank shapedcharges [8].

Tritium boosting has a number of significant technical and military advantages, which explain why it is used in essentially all militarized nuclear weapons, including in India, Pakistan, and North Korea. While it is sometimes described as easy to implement, other reports suggest that the tritium boosting mechanism failed in early Indian and North Korean tests. These advantages comprise: ( high transparence to Xrays, deriving from the fact that a boosted device does not need a thick and heavy neutronreflector/ tamper to insure a sufficient yield, so that most of the energy released by the neutron chainreaction (which at the end of the fission explosion is found in the form of hardXrays) can easily escape from the fissioned material.
 * high efficiency with relatively low compression and thin reflector/tamper;
 * low weight and small size;
 * intrinsic safety capability (zero or negligible yield when the tritium is not in the weapon2);
 * preinitiationproof capability (resistance to neutrons from spontaneousfission or other warheads);

The first effect of these Xrays is to heat the surrounding materials, such as the compressed reflector/tamper and the detonation products of the highexplosive that imploded these materials, as well as the shell of heavy material (e.g., steel or uranium – sometimes called the “barrel shell”) which is generally used to contain the highexplosives. Consequently, if this outershell is sufficiently thick and opaque to Xrays (e.g., 1 cm of uranium), it will become extremely hot and therefore behave as a secondary source of Xrays: This is the principle of the “hot softXray source” which is used as the “primary” of a twostage Hbomb. 3

2The boost gas has a small neutronmoderating effectwhich can be exploited to design a weapon in such a way that a diverging chain reaction stops at an early stage when no boost gas is present in the pit. This is difficult to achieve in practice and required many tests in the past, in particular to ensure “onepoint safety” (which in fact can only be secured when there is no boost gas in the pit). 3Since the diameter of this outershell is about ten times the diameter of the compressed fission material, the duration of the softXray pulse from the barrel shell will also be about ten times the duration of the Xray pulse from the fissioned material — an important consideration if the pulse is to compress the fusion material of an Hbomb secondary.