Ion traps — recent applications and developments

Paul and Penning traps are now widely applied in chemistry and physics laboratories. They are used as storage devices, as tools for precision spectroscopy and metrology, and as mass spectrometers. Direct mass measurements of short-lived Rb, Sr, Cs, Ba, Fr and Ra isotopes were performed at the on-line mass separator ISOLDE at CERN, Geneva, by means of a tandem Penning trap system. The ions from ISOLDE are captured and cooled in a first trap and trasnferred to a second trap. Here the mass of the trapped ions is determined by measuring their cyclotron frequency. Resolving powers exceeding m/Δm (FWHM) = 10⁶ could be achieved. Mass values of about 60 isotopes have been determined with accuracies of typically δm/m = 10⁻⁷. For the first time in the history of mass spectrometry the isomeric and ground states of a nucleus have been resolved.