Study of Cooling and Storage Properties of a Gas-Filled Linear Paul Trap Coupled to a Time-of-Flight Mass Spectrometer for Mass Measurements of Exotic Nuclei

A gas-filled radio-frequency quadrupole has been developed, which acts as an interface between a time-of-flight mass spectrometer and an atmospheric-pressure ion source or a gas-filled ion beam stopping cell. It delivers cooled continuous or bunched beams to the mass analyzer. The radio-frequency quadrupole has been characterized and the longitudinal energy distributions, bunching efficiencies and beam losses as a function of storage time, and the duty cycle improvement have been measured. Using the bunch mode, the mass-resolving power of the time-of-flight mass spectrometer could be increased by a factor of about two and now amounts to 24 000 (full width at half maximum).