Einsteinium was first discovered through the examination of debris that occurred after hydrogen bomb testing. The element had been synthesized in an isotopic form, number 253, from the nuclear fusion of the hydrogen bomb; it had a half life of 20.5 days. Einsteinium was then synthesized years later by using the isotope, number 239, of plutonium; this isotope was bombarded with neutrons and minute quantities of einsteinium resulted. Today, einsteinium is produced infrequently and in very small amounts. The process involves the irradiation of the plutonium isotope number 239. The irradiation process results in the plutonium isotope, number 242, which is then combined with aluminum metal to form a pellet like compound. These pellets are then irradiated again during a year long process in a nuclear reaction. After this procedure, four more months of irradiation must be carried out in a separate reactor. From these procedures, a compound containing einsteinium and californium is formed. These elements can then be separated from one another.