β-decay of neutron-rich Z∼60 nuclei and the origin of rare earth elements

Abstract

Abstract. A large fraction of the rare-earth elements observed in the solar system is produced in the astrophysical rapid neutron capture process (r-process). However, current stellar models cannot completely explain the relative abundance of these elements partially because of nuclear physics uncertainties. To address this problem, a β -decay spectroscopy experiment was performed at RI Beam Factory (RIBF) at RIKEN, aimed at studying a wide range of very neutron-rich nuclei with Z∼60 that are progenitors of the rare-earth elements with mass number A∼160. The experiment provides a test of nuclear models as well as experimental inputs for r-process calculations. This contribution presents the experimental setup and some preliminary results of the experiment.

β -decay half-lives of 55 neutron-rich isotopes beyond the N=82 shell gap

“…The WAS3ABi includes a stack of five Double Sided Silicon Strip Detectors (DSSSDs) with 1 mm both for the width of each strip and the thickness of each DSSSD. The prompt and β-delayed γ rays emitted from the implanted isotopes were detected by the 84 germanium cluster detectors of the Euroball RIken Cluster Array, which surrounded the WAS3ABi [18][19][20]. The particle identification plot was constructed by the TOF-Bρ-E principle with the measurements from the detectors along the beam line of the BigRIPS separator, including plastic scintillators, ionization chambers, as well as a variety of deflection magnets [21].…”

Heavy rotation – evolution of quadrupole collectivity centred at the neutron-rich doubly mid-shell nucleus 170Dy

“…In April 2012, the setup was successfully commissioned [14] and since then a number of large data sets have been collected focused on different regions of the Segré chart. The first experiment with a uranium beam was performed in December 2012 in the 78 Ni region [17] and since then β-decay data have been collected covering most of the neutron-rich part of the nuclear chart up to the rare-earth region [18,19,20]. In parallel to the decay data, isomer decay information has been collected reaching all the way up to 166 Gd [21].…”

“…Chae 16 , Zs. Dombradi 6 , A. Estrade 17 , N. Fukuda 1 , C. Griffin 17 , E. Ideguchi 13,18 , N. Inabe 1 , T. Isobe 1 , H. Kanaoka 13 , I. Kojouharov 19 , F.G. Kondev 20 , T. Kubo 1 , S. Kubono 1 , N. Kurz 19 , I. Kuti 6 , S. Lalkovski 2 , G. J. Lane 21 , C.S.…”