Nuclear Structure of SHN – State of the Art and Perspectives at S3

Abstract : The new separator-spectrometer combination S3, presently under construction at the new SPIRAL2 facility of GANIL, Caen, France, together with the high intensity beams of SPIRAL 2’s SC LINAC, will offer exciting perspectives for a wide spectrum of nuclear and atomic physics topics. Among the mayor features to be studied, apart from nuclei in the N=Z region, nuclei of astrophysical relevance and some atomic physics issues, are the properties of the heaviest nuclei (superheavy nuclei – SHN). The installation is designed to employ nuclear physics methods like decay spectroscopy after separation or atomic physics methods like laser spectroscopy and mass measurements. The nuclear physics studies will include particle and photon correlation studies, attacking the open questions in the field, which have been revealed in earlier studies at facilities like e.g. GSI with the velocity filter SHIP and the gas-filled separator TASCA, Jyväskylä with RITU and its numerous auxiliary detection set-ups, the DGFRS and VASSILISSA/SHELS separators at FLNR/JINR in Dubna etc. The research subjects include K-isomers, isotopic and isotonic trends of low lying nuclear excitations and $\gamma$-electron-$\alpha$ and $\gamma-electron-fission coincidences. The detection array SUIRIUS at the focal plane of S3, presently being developed for this purpose, is also an ideal tool to study delayed processes like isomeric states and β-delayed fission. A low energy set-up including a gas stopping cell, laser spectroscopy instrumentation and a multi-reflection time-of-flight spectrometer, will be used to study nuclei in the N=Z region as well as the heaviest nuclear species. In a farer future the synthesis and investigation of, also so far unknown, highest-Z systems is envisaged, for which the earlier experiments will produce the basis. The state of the art of the SHN spectroscopy will be presented and an outline for the physics program at S3 will be given in this presentation.