An apparatus for focusing and for storage of ions and an apparatus for separation of a first pressure area from a second pressure area are disclosed, in particular for an analysis apparatus for ions. A particle beam device may have at least one of the abovementioned apparatuses. A container for holding ions and at least one multipole unit are provided. The multipole unit has a through-opening with a longitudinal axis as well as a multiplicity of electrodes. A first set of the electrodes is at a first radial distance from the longitudinal axis. A second set of the electrodes is in each case at a second radial distance from the longitudinal axis. The first radial distance is less than the second radial distance. Alternatively or additionally, the apparatus may have an elongated opening with a radial extent. The opening has a longitudinal extent which is greater than the radial extent.