Speaker
Description
The stability of nuclei beyond the spherical double shell closure of $^{208}$Pb rapidly decreases because of the disappearance of the macroscopic fission barrier. This phenomenon is however compensated by quantum shell effects caused by alternating zones of high and low densities caused by deformation. The island of superheavy stability is foreseen as a doubly spherical gap whose position varies depending on the model used. Spectroscopy in the region of high masses is very close to the limits of the existing detection systems. The extension of the investigation on nuclear structure to heavier nuclei is governed by an improvement in the efficiency of the transport and selection of the nuclei of interest as well as in the detection systems. The very high intensity beams provided by the NEW GAnil INjector (NEWGAIN) and the LINear ACcelerator (LINAC), combined with the high transmission and selection power of the Super Separator Spectrometer (S$^3$) will offer unprecedented production rates of nuclei in the picoobarns region.
SIRIUS (Spectroscopy and Identification of Rare Isotopes Using S$^3$) will be the detection system dedicated to spectroscopy experiments for superheavy nuclei with S$^3$. SIRIUS consists of five segmented silicon detectors optimized for precision spectroscopy of alpha, beta and fission decay, surrounded by five EXOGAM high-purity germanium detectors for gamma-rays, and a Secondary Emission Detector (SED) placed upstream to track the ions and measure their time of flight. The conjunction of these detectors with the mass resolving power and the transmission of S$^3$ will make it a unique instrument for the study of superheavy nuclei.
In this contribution, after a brief review of the current status of S$^3$, we will report on the offline tests of SIRIUS and the performances of its detectors.
