Neutron bombs, also called enhanced radiation bombs (ER weapons), are small thermonuclear weapons in which the burst of neutrons generated by the fusion reaction is intentionally not absorbed inside the weapon, but allowed to escape. The X-ray mirrors and shell of the weapon are made of chromium or nickel so that the neutrons are permitted to escape. Contrast this with cobalt bombs, also known as salted bombs.
This intense burst of high-energy neutrons is the principal destructive mechanism.
The term "enhanced radiation" refers only to the burst of ionizing radiation released at the moment of detonation, not to any enhancement of residual radiation in fallout.
A neutron bomb requires considerable amounts of tritium, which has a half-life of 12.3 years. The neutron bombs that existed in the United States arsenal in the past were variants of the W70 and the W79 designs
The neutron bomb is generally credited to Samuel Cohen of the Lawrence Livermore National Laboratory, who developed the concept in 1958. Although initially opposed by President John F. Kennedy, its testing was authorized and carried out in 1962 at a Nevada test site. Development was subsequently cancelled by President Jimmy Carter in 1978, but again restarted by President Ronald Reagan in 1981[1]. The weapons were sparsely deployed and no longer exist. Enhanced radiation weapons were also produced by France in the early 1980s, and in 1999 reports indicated that China had gained the ability to produce neutron bombs.