Tritium consists of about 4.5 kilograms of plutonium-239. Since tritium undergoes radioactive decay, and is also difficult to confine physically, the much larger secondary charge of heavy hydrogen isotopes needed in a true hydrogen bomb uses solid lithium deuteride as its source of deuterium and tritium, producing the tritium "in situ" during secondary ignition. During the detonation of the primary fission bomb stage in a thermonuclear weapon (Teller-Ullam staging), the sparkplug, a cylinder of U-235/Pu-239 at the center of the fusion stage(s), begins to fission in a chain reaction, from excess neutrons channeled from the primary. The neutrons released from the
On-Line Isotope Mass Separator On-Line Isotope Mass Separator The On-Line Isotope Mass Separator, also known as the ISOLDE Radioactive Ion Beam Facility, is a facility located at CERN on the PS Booster. It started operating in 1967 and was rebuilt twice with major upgrades in 1974 and 1992. ISOLDE (Isotope Separator On Line DEtector) is dedicated to producing radioactive nuclei for a number of applications covering nuclear, atomic, molecular and solid-state physics, but also biophysics and astrophysics. The large variety of available species allows the systematic study of atomic and nuclear properties and exotic decays far from the line of stability. As of 2006,