PRESPEC: Driving on the FAIR road of HISPEC/DESPEC

Fingerprinting excited nuclear states by γ-ray spectroscopy has been a viable tool to benchmark nuclear models for decades. Since contemporay nuclear structure investigations aim at the study and understanding of very exotic nuclei at the limits of stability and their decay properties, large and thus highly efficient γ-ray spectroscopy instruments are the basis for continued discoveries into the terra incognita of the nuclidic chart, while the key for future breakthroughs in high-resolution in-beam spectroscopy at relativistic energies lies in the implementation of highly segmented Ge-detector arrays such as AGATA, which are going to phase out the present-day limitations of Doppler broadened γ-ray lines. The HISPEC/DESPEC collaboration within NUSTAR has its roots in the major pan-European programme ’Rare Isotope Spectroscopic INvestigations at GSI’ (RISING), which started in the year 2003. RISING combined the concept of efficient and high-resolution γ-ray spectroscopy based upon 105 Ge-detector crystals confined in fifteen former EUROBALL Cluster-detectors with well-defined relativistic radioactive ion beams. The latter are at present produced in-beam by fragmentation or relativistic fission of primary beams from the heavy-ion synchrotron (SIS) at GSI, and subsequently the reaction products are separated, identified on an ion-by-ion basis, and finally focussed towards the RISING spectrometer by means of the FRagment Separator (FRS).