Decay and Fission Hindrance of Two- and Four-Quasiparticle K Isomers in ^{254}Rf

Search for Electron-Capture Delayed Fission in the New Isotope ^{244}Md

The electron-capture decay followed by a prompt fission process was searched for in the hitherto unknown most neutron-deficient Md isotope with mass number 244. Alpha decay with α-particle energies of 8.73-8.86 MeV and with a half-life of 0.30_{-0.09}^{+0.19}  s was assigned to ^{244}Md. No fission event with a similar half-life potentially originating from spontaneous fissioning of the short-lived electron-capture decay daughter ^{244}Fm was observed, which results in an upper limit of 0.14 for the electron-capture branching of ^{244}Md. Two groups of fission events with half-lives of 0.9_{-0.3}^{+0.6}  ms and 5_{-2}^{+3}  ms were observed. The 0.9_{-0.3}^{+0.6}  ms activity was assigned to originate from the decay of ^{245}Md. The origin of eight fission events resulting in a half-life of 5_{-2}^{+3}  ms could not be unambiguously identified within the present data while the possible explanation has to invoke previously unseen physics cases.

Nuclear and chemical characterization of heavy actinides

Recent progress in the production of heavy nuclei far from stability and in the studies of nuclear and chemical properties of heavy actinides is briefly reviewed. Exotic nuclear decay properties including nuclear fission of heavy nuclei, measurements of first ionization potentials of heavy actinides, and redox studies of heavy actinides are described. Brief history of discovery of the transuranium elements is also presented.

Nuclear structure of superheavy nuclei - state of the art and perspectives (@ S3)

Decay spectroscopy is a powerful tool to study the low lying nuclear structure of heavy and superheavy nuclei (SHN). Single particle levels and other structure features like K isomerism, being important in the fermium-nobelium region as well as for the spherical shell stabilized SHN, can be investigated. 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 SPIRAL2’s superconducting linear accelerator (SC LINAC), will offer exciting perspectives for a wide spectrum of nuclear and atomic physics topics. 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 in Darmstadt, Germany, with the velocity filter SHIP and the gas-filled separator TASCA, the cyclotron accelerator laboratory of the University of Jyväskylä, Finland, with RITU and its numerous auxiliary detection set-ups, and FLNR/JINR in Dubna with the DGFRS and VASSILISSA/SHELS separators.

Review of metastable states in heavy nuclei

The structure of nuclear isomeric states is reviewed in the context of their role in contemporary nuclear physics research. Emphasis is given to high-spin isomers in heavy nuclei, with [Formula: see text]. The possibility to exploit isomers to study some of the most exotic nuclei is a recurring theme. In spherical nuclei, the role of octupole collectivity is discussed in detail, while in deformed nuclei the limitations of the K quantum number are addressed. Isomer targets and isomer beams are considered, along with applications related to energy storage, astrophysics, medicine, and experimental advances.