Over the past few years a great deal of new spectroscopic data has been obtained for transfermium nuclei. Recoil separators, coupled with modern target position and focal-plane spectrometers, allow detailed studies of the structure and decay properties of transfermium nuclei to be peformed. In-beam studies using the recoil-gating and recoil-decay tagging techniques mainly provide information on yrast states, whilst complementary focal-plane decay studies give access to non-yrast and isomeric structures. In-beam studies of nuclei in this region have largely been performed at ANL and JYFL, and decay experiments at GSI, JYFL, GANIL and ANL. The present contribution is focussed on recent developments and experiments carried out by a number of collaborating institutes at JYFL. ; This work has been supported by the European Union Fifth Framework Programme "Improving Human Potential - Access to Research Infrastructure" Contract No. HPRI-CT-1999- 00044 and by the Academy of Finland under the Finnish Centre of Excellence Programme 2000-2005 (Project No. 44875, Nuclear and Condensed Matter Physics Programme at JYFL).
Over the past few years a great deal of new spectroscopic data has been obtained for transfermium nuclei. Recoil separators, coupled with modern target position and focal-plane spectrometers, allow detailed studies of the structure and decay properties of transfermium nuclei to be peformed. In-beam studies using the recoil-gating and recoil-decay tagging techniques mainly provide information on yrast states, whilst complementary focal-plane decay studies give access to non-yrast and isomeric structures. In-beam studies of nuclei in this region have largely been performed at ANL and JYFL, and decay experiments at GSI, JYFL, GANIL and ANL. The present contribution is focussed on recent developments and experiments carried out by a number of collaborating institutes at JYFL. ; This work has been supported by the European Union Fifth Framework Programme "Improving Human Potential - Access to Research Infrastructure" Contract No. HPRI-CT-1999- 00044 and by the Academy of Finland under the Finnish Centre of Excellence Programme 2000-2005 (Project No. 44875, Nuclear and Condensed Matter Physics Programme at JYFL).
11 pags., 10 figs., 5 tabs.-- Open Access funded by Creative Commons Atribution Licence 4.0 ; The structure of Si34 was studied through γ spectroscopy separately in the β- decays of Mg34 and Al34 at the ISOLDE facility of CERN. Different configurations in Si34 were populated independently from the two recently identified β-decaying states in Al34 having spin-parity assignments Jπ=4- dominated by the normal configuration π(d5/2)-1 - ν(f7/2) and Jπ=1+ by the intruder configuration π(d5/2)-1 - ν(d3/2)-1(f7/2)2. The paper reports on spectroscopic properties of Si34 such as an extended level scheme, spin and parity assignments based on log(ft) values and γ-ray branching ratios, absolute β feeding intensities, and neutron emission probabilities. A total of 11 newly identified levels and 26 transitions were added to the previously known level scheme of Si34. Large scale shell-model calculations using the SDPF-U-MIX interaction, able to treat higher order intruder configurations, are compared with the new results and conclusions are drawn concerning the predictive power of SDPF-U-MIX, the N=20 shell gap, the level of mixing between normal and intruder configurations for the 01+, 02+, and 21+ states, and the absence of triaxial deformation in Si34. ; This work was partially supported by a grant of the Romanian National Authority for Scientific Research and Innovation, CNCS-UEFISCDI project number PN-II-RU-TE- 2014-4-1455, by the Romanian IFA Grant CERN/ISOLDE, by Research Foundation Flanders (FWO-Belgium), by GOA/2015/010 (BOF KU Leuven), and by the Interuniversity Attraction Poles Programme initiated by the Belgian Science Policy Office (BriX network P7/12). Support from the U.K. Science and Technology Facilities Council, the European Union Seventh Framework through ENSAR (Contract No. 262010), the MINECO (Spain) grants FPA2017-87568-P, FPA2015-64969-P, FPA2014-57196, FPA2015-65035-P, Programme "Centros de Excelencia Severo Ochoa" SEV-2016- 0597, the MEYS project SPIRAL2-CZ,EF16-013/0001679, the National Research, Development and Innovation Fund of Hungary via Project No. K128947, the European Regional Development Fund (Contract No. GINOP-2.3.3-15-2016- 00034), the German BMBF under contract 05P18PKCIA (ISOLDE), and "Verbundprojekt 05P2018" is also acknowledged. I.K. was supported by the National Research, Development and Innovation Office of Hungary (NKFIH), Contract No. PD 124717. ; Peer Reviewed
13 pags., 7 figs., 3 tabs. ; A new β-decaying state in Bi214 has been identified at the ISOLDE Decay Station at the CERN-ISOLDE facility. A preferred Iπ=(8-) assignment was suggested for this state based on the β-decay feeding pattern to levels in Po214 and shell-model calculations. The half-life of the Iπ=(8-) state was deduced to be T1/2=9.39(10) min. The deexcitation of the levels populated in Po214 by the β decay of this state was investigated via γ-γ coincidences and a number of new levels and transitions was identified. Shell-model calculations for excited states in Bi214 and Po214 were performed using two different effective interactions: the H208 and the modified Kuo-Herling particle interaction. Both calculations agree on the interpretation of the new β-decaying state as an Iπ=8- isomer and allow for tentative assignment of shell-model states to several high-spin states in Po214. ; This work has been supported by the Research Foundation Flanders (FWO, Belgium), by GOA/2015/010 (BOF KU Leuven), the Interuniversity Attraction Poles Programme initiated by the Belgian Science Policy Office (BriX network P7/12), by the ENSAR2: European Union's Horizon 2020 research and innovation programme under Grant Agreement No. 654002, by the U.K. Science and Technology Facilities Council, by the Slovak Research and Development Agency (Contract No. APVV-18-0268), by the Slovak grant agency VEGA (Contract No. 1/0651/21), by RFBR according to the research project N 19-02-00005, by the Romanian IFA Grant CERN/ISOLDE, by the Spanish Funding Agency (AEI) under the project PID2019-104390GB-I00, by the German BMBF under Grant No. 05P18PKCIA and by the Spanish Ministerio de Ciencia e Innovación grant PID2019-104714GB-C21. M.S. acknowledges funding from the European Union's Horizon 2020 research and innovation program under Grant Agreement No. 771036 (ERC CoG MAIDEN). ; Peer reviewed
10 pags., 8 figs., 1 tab.-- Open Access funded by Creative Commons Atribution Licence 4.0 ; Excited states in Sn133 were investigated through the ß decay of In133 at the ISOLDE facility. The ISOLDE Resonance Ionization Laser Ion Source (RILIS) provided isomer-selective ionization for In133, allowing us to study separately, and in detail, the ß-decay branch of In133J¿=(9/2+) ground state and its J¿=(1/2-) isomer. Thanks to the large spin difference of the two ß-decaying states of In133, it is possible to investigate separately the lower and higher spin states in the daughter, Sn133, and thus to probe independently different single-particle and single-hole levels. We report here new ¿ transitions observed in the decay of In133, including those assigned to the deexcitation of the neutron-unbound states. ; We acknowledge the support of the ISOLDE Collaboration and technical teams. This work was supported in part by the Polish National Science Center under Contract No. UMO-2015/18/E/ST2/00217 and under Contract No. UMO-2015/18/M/ST2/00523, by the Spanish MINECO via FPA2015-65035-P project, by the Portuguese FCT via CERN/FIS-NUC/0004/2015 and CERN-FIS-PAR-0005-2017 projects. The research leading to these results has received funding from the European Union's Horizon 2020 research and innovation programme under Grant Agreement No. 654002.
