Isotopes of iridium
There are two natural isotopes of iridium (Ir), and 34 radioisotopes, the most stable radioisotope being Ir with a half-life of 73.83 days, and many nuclear isomers, the most stable of which is Ir with a half-life of 241 years. All other isomers have half-lives under a year, most under a day. All isotopes of iridium are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed. Iridium-192. Iridium-192 (symbol Ir) is a radioactive isotope of iridium, with a half-life of 73.83 days . It decays by emitting beta (β) particles and gamma (γ) radiation. About 96% of Ir decays occur via emission of β and γ radiation, leading to Pt. Some of the β particles are captured by other Ir nuclei, which are then converted to Os. Electron capture is responsible for the remaining 4% of Ir decays. Iridium-192 is normally produced by neutron activation of natural-abundance iridium metal. Iridium-192 is a very strong gamma ray emitter, with a gamma dose-constant of approximately 1.54 μSv·h·MBq at 30 cm, and a specific activity of 341 TBq·g (9.22 kCi·g). There are seven principal  energy packets produced during its disintegration process ranging from just over 0.2 to about 0.6 MeV. Iridium-192 is commonly used as a gamma ray source in industrial radiography to locate flaws in metal components. It is also used in radiotherapy as a radiation source, in particular in brachytherapy. Iridium-192 has accounted for the majority of cases tracked by the U.S Nuclear Regulatory Commission in which radioactive materials have gone missing in quantities large enough to make a dirty bomb. The Ir isomer is unusual, both for its long half-life for an isomer, and that said half-life greatly exceeds  that of the ground state of the same isotope.