Speaker
Prof.
Peter Egelhof
(GSI Darmstadt)
Description
Light-ion induced direct reactions, like for example elastic and inelastic scattering, transfer-, charge exchange-, or knock out-reactions, have been proved in the past, for the case of stable nuclei, to be powerful tools for obtaining nuclear structure information, and were also applied within the last two decades for the investigation of exotic nuclei with radioactive beams in inverse kinematics. In particular, it turned out that in many cases essential nuclear structure information is deduced from high-resolution measurements at low momentum transfer. For the case of inverse kinematics experiments with radioactive beams such measurements can be performed either by using the experimental technique of active targets, or, with even higher luminosities, with stored radioactive beams.
Within the EXL(1) project it was proposed to investigate direct reactions with radioactive beams, stored and cooled in a storage ring, interacting with thin internal targets. This technique enables high resolution measurements down to very low momentum transfer and provides a gain in luminosity from accumulation and recirculation of the radioactive beams. A brief overview on the research objectives, the technical concept and the present status of the EXL project, as well as on feasibility studies and first experiments performed or planned at the present ESR storage ring, paving the way towards the full EXL experiment at FAIR, will be presented. In particular, the results of a first experiment with stored radioactive 56Ni beam, where the nuclear matter distribution of the doubly magic 56Ni nucleus was investigated by elastic proton scattering, and a feasibility study on 58Ni(α,α`) inelastic scattering, where it was demonstrated that the Giant Monopole Resonance in 58Ni can be investigated by the present technique down to cm angles below 1 degree, will be discussed.
As alternative method for low momentum transfer measurements, in particular for very short lived nuclei with lifetimes below 1 sec, the technique of active targets is well suited. An overview on recent results, obtained with the IKAR active target on matter distributions of halo nuclei, and on the future perspectives at FAIR will be presented.
(1) EXL: EXotic nuclei studied in Light-ion induced reactions at the NESR storage ring
Primary author
Prof.
Peter Egelhof
(GSI Darmstadt)
