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The relative momentum spread of in-flight separated exotic nuclear beams produced in fragmentation and/or fission reactions is of the order of a few percent. A new technique is presented, which reduces the momentum spread significantly, and first experimental results obtained with relativistic projectile fragments are shown. This technique is the key to experiments with slowed-down and stopped beams, in particular for the efficient stopping of relativistic exotic nuclei in gas-filled stopping cells. It will be employed at the energy-buncher stage of the low-energy branch of the Super-FRS facility. The ion-optical design of the energy buncher is presented and a brief outlook to the experimental program is given.

Iron-free magnetic quadrupole lenses have been developed for the focusing of energetic bunched heavy-ion beams. These devices are operated in a pulsed mode and provide very strong magnetic fields. A magnetic flux density of more than 14 T has been reached in a 100 mm long quadrupole with a 20 mm wide aperture, which corresponds to a magnetic flux density of ∼1400 T/m. The pulse duration of the applied electric current is approximately 300 μs with a flat top of several μs. The calculated and measured field properties of the quadrupoles are presented. In a first test experiment with a fast-extracted 650 MeV/u 197 Au 79+ beam (bunch length ∼500 ns) at GSI the focusing properties could be demonstrated. As a possible application the ion-optical design of a condenser lens system will be presented. With this system the phase-space enlargement in a nuclear reaction target can be significantly reduced, thus leading to an increased collection efficiency of a fragment separator or, more general, of any ion-optical device. In particular this is advantageous for injection of secondary beams into a storage ring.

The charge-exchange contribution can dominate the energy-loss straggling of partially stripped heavy ions depending on the charge-changing cross sections and the partial stopping powers. We have studied the energy-loss straggling of few-electron uranium ions in different solids in the energy range of (200–1000) MeV/u. Our experimental data are compared with a new model taking into account realistic screening for relativistic scattering of target electrons at close impacts to derive partial stopping powers. Screening of the projectile nucleus by inner-shell electrons reduces the charge-exchange straggling compared to that pertaining to a point-like charge distribution.

Pulsed magnetic quadrupole lenses have been developed for focusing high energetic heavy ion beams. The quadrupoles were built using iron-free structures. Up to now a magnetic flux density above 14 T has been reached in a quadrupole of 22 mm aperture. The field properties of the quadrupoles are presented. In an experiment with a heavy ion beam the focusing properties were investigated. This development can be used for building a condensor system to increase the collection efficiency of a downstream ion optical devices for nuclear reaction products.

The GSI projectile fragment separator FRS has demonstrated with many pioneering experiments the research potential of in-flight separators at relativistic energies. Although the present facility has contributed much to the progress in the field of nuclear structure physics, major improvements are desirable in the future. The characteristics of the proposed next-generation facility at GSI, the Super-FRS, will be presented and compared to other projects. The Super-FRS is a large-acceptance superconducting fragment separator followed by different experimental branches including a combination with a new storage-cooler ring system. This system consists of a collector ring (CR) and a new experimental storage ring (NESR) which allow precision mass and lifetime measurements as well as in-ring reaction studies. The NESR can be operated in combination with an electron ring to measure electron scattering with exotic nuclei. This electron heavy-ion collider will open up new fields for nuclear structure research.

The pulsed magnetic quadrupole lenses have been developed for focusing high energetic ion beams in accelerators. To operate stably, the quadrupole lenses were built in optimized steel- free structures. Up to now a flux density above 14 T has been reached in a quadrupole of 22 mm aperture. This value is high than the values reached in superconducting quadrupole lenses.