Isotope persisted down to the present because their rate of decay is so slow (e.g. uranium-238 and potassium-40). Post-primordial isotopes were created by cosmic ray bombardment as cosmogenic nuclides (e.g., tritium, carbon-14), or by the decay of a radioactive primordial isotope to a radioactive radiogenic nuclide daughter (e.g. uranium to radium). A few isotopes are naturally synthesized as nucleogenic nuclides, by some other natural nuclear reaction, such as when neutrons from natural nuclear fission are absorbed by another atom. As discussed above, only 80 elements have any stable isotopes, and 26 of these have only one stable isotope. Thus, about two-thirds
On-Line Isotope Mass Separator or to the REX accelerator for acceleration to higher energies. The facility is operated by the ISOLDE Collaboration comprising CERN and 9 European countries. One of the major experiments in ISOLDE is the Miniball-setup. An upgrade of the post-acceleration system is currently on-going, ready to produce energetic Radioactive-Ion Beams (RIBs) of up to 10 MeV per nucleon in 2018. 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