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R. Lica et al. -- 6 pags., 3 figs. -- Open Access funded by Creative Commons Atribution Licence 4.0 ; The β- decay of Mg34 was used to study the Al34 nucleus through γ spectroscopy at the Isotope Separator On-Line facility of CERN. Previous studies identified two 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. Their unknown ordering and relative energy have been the subject of debate for the placement of Al34 inside or outside the N=20 >island of inversion.> We report here that the 1+ intruder lies only 46.6 keV above the 4- ground state. In addition, a new half-life of T1/2=44.9(4)ms, that is twice as long as the previously measured 20(10) ms, has been determined for Mg34. Large-scale shell-model calculations with the recently developed sdpf-u-mix interaction are compared with the new data and used to interpret the mechanisms at play at the very border of the N=20 island of inversion. ; This Rapid Communication was partially supported by a grant of the Romanian National Authority for Scientific Research and Innovation, CNCS-UEFISCDI Project No. PN-II-RU-TE-2014-4-1455, the Romanian IFA Grant CERN/ISOLDE, by FWO-Vlaanderen (Belgium), by GOA/2010/010 (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 No. FPA2015-64969- P, No. FPA2014-57196, and No. FPA2015-65035-P, Programme "Centros de Excelencia Severo Ochoa" Program No. SEV-2012-0249, the German BMBF under Contract No. 05P15PKCIA (ISOLDE), and "Verbundprojekt 05P2015" also is acknowledged. ; Peer Reviewed

R. Lica et al. -- 14 pags., 7 figs., tab. -- Open Access funded by Creative Commons Atribution Licence 3.0 ; Neutron-rich Ba isotopes are expected to exhibit octupolar correlations, reaching their maximum in isotopes around mass A = 146. The odd-A neutron-rich members of this isotopic chain show typical patterns related to non-axially symmetric shapes, which are however less marked compared to even-A ones, pointing to a major contribution from vibrations. In the present paper we present results from a recent study focused on Cs β-decay performed at the ISOLDE Decay Station equipped with fast-timing detectors. A detailed analysis of the measured decay half-lives and decay scheme of Ba is presented, giving a first insight in the structure of this neutron-rich nucleus. ; The IDS collaboration acknowledges financial support from: Istituto Nazionale di Fisica Nucleare, the Italian 'Programmi di Ricerca Scientifica di Rilevante Interesse Nazionale (PRIN)' contract number 2001024324 01302, the European Union's seventh framework through ENSAR, contract no. 262010, the European Unions Horizon 2020 Framework research and innovation programme under grant agreement no. 654002 (ENSAR2), the FATIMA-NuPNET network via the PRI-PIMNUP-2011-1338 project, the Spanish MINECO projects reference numbers FPA2013-41467-P and FPA2015-646969-P, the German BMBF under contract 05P15PKCIA and 'Verbundprojekt 05P2015', the FWO-Vlaanderen (Belgium) and the IAP Belgian Science Policy (BriX network P7/12). VCh and ZP acknowledge support by the polish grant of Narodowe Centrum Nauki nr 2015/18/M/ST2/00523. ; Peer Reviewed

6 pags., 6 figs. -- 27th International Nuclear Physics Conference (INPC2019) 29 July - 2 August 2019, Glasgow, UK ; The neutron-deficient 115Cs was produced at ISOLDE, CERN by spallation reaction using 1.4 GeV proton on LaC2 target. The exotic decay modes were studied by using a charged particle array (DSSD and pad detectors) and a ¿-detector array (four Clovers) at the ISOLDE decay station (IDS). In this report, results on observed ß-delayed particle emission from 115Cs, a nucleus close to proton drip line, is presented. By measuring the time distribution in the delayed proton spectrum, the half-life of the ground state of 115Cs was extracted. The obtained half-life is in agreement with previous reported value. For the first time, the p-unbound states of 115Xe, obtained by measuring beta-delayed protons from 115Cs is reported. ; Ushasi Datta acknowledges with thanks to SERB, India for the financial support (travel) for attending and presenting the paper in the conference (INPC2019). Authors of SINP deeply acknowledge the SEND (XI th plan, DAE, India) and IENP/HENPP (XII th plan, DAE, India) project grant. This project has received funding from the European Union's Horizon 2020 ENSAR2 project under grant agreement no 654002 and the Spanish research council under contract FPA2015-64969-P. The authors (P.Das and A.Bhattacharyya) acknowledge with thanks the financial support provided by the CSIR vide file number 09/489(0111)/2019EMR-I and 09/489(0115)/2019EMR-I respectively.

6 pags., 4 figs., 1 tab. ; The β decay of Hg208 into the one-proton hole, one neutron-particle Tl81208127 nucleus was investigated at CERN-ISOLDE. Shell-model calculations describe well the level scheme deduced, validating the proton-neutron interactions used, with implications for the whole of the N>126, Z<82 quadrant of neutron-rich nuclei. While both negative and positive parity states with spin 0 and 1 are expected within the Qβ window, only three negative parity states are populated directly in the β decay. The data provide a unique test of the competition between allowed Gamow-Teller and Fermi, and first-forbidden β decays, essential for the understanding of the nucleosynthesis of heavy nuclei in the rapid neutron capture process. Furthermore, the observation of the parity changing 0+→0-β decay where the daughter state is core excited is unique, and can provide information on mesonic corrections of effective operators. ; This work was supported by the European Union under Contracts No. 262010 (ENSAR) and No. 654002 (ENSAR2), the Science and Technology Facilities Council (UK), the German BMBF under Contract No. 05P18PKCIA and "Verbundprojekt 05P2018," the MINECO Projects No. FPA2015-65035-P, No. RTI2018- 098868-B-I00, No. FPA2015-64969-P, and No. FPA2017- 87568-P (Spain), FWO-Vlaanderen (Belgium), GOA/ 2015/010 (BOF KU Leuven), the Excellence of Science programme (EOS-FWO), the Interuniversity Attraction Poles Programme initiated by the Belgian Science Policy Office (BriX network P7/12), the Romanian IFA project CERN-RO/ISOLDE and the Polish National Science Centre under Contracts No. UMO-2015/18/M/ST2/00523 and No. UMO-2019/33/N/ST2/03023. P. H. R. and S. M. J. acknowledge support from the UK Department for Business, Energy and Industrial Strategy via the National Measurement Office. Zs. P. acknowledges support from the ExtreMe Matter Institute EMMI at the GSI Helmholtzzentrum fr Schwerionenforschung, Darmstadt, German

The structure of 208Po resulting from the EC/β + decay of 208At was studied at CERN's ISOLDE Decay Station (IDS). The high statistics afforded by the high yield of 208At and the high efficiency HPGe clusters at the IDS allowed for greater insight into lower intensity transitions and thus significant expansion of the 208Po level scheme. Furthermore, investigation into the isomeric state yielded a new half life 377(9) ns in addition to uncovering new transitions populating the state. ; 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. As well as the Science and Technology Facilities Council (UK) through grants ST/P005314/1, ST/L005743/1, ST/J000051/1, ST/L005670/1, and ST/P004598/1 and (PHR) by the UK Department of Business, Energy and Industrial Strategy (BEIS) via the National Measurement System. Further funding was provided by the German BMBF under contract 05P18PKCIA and "Verbundprojekt 05P2018" as well as the Spanish MINECO grant FPA2015-65035-P. ; Peer reviewed

12 pags., 5 figs., 3 tabs. ; The β decay of Hg207 into the single-proton-hole nucleus Tl207 has been studied through γ-ray spectroscopy at the ISOLDE Decay Station (IDS) with the aim of identifying states resulting from coupling of the πs1/2-1, πd3/2-1, and πh11/2-1 shell model orbitals to the collective octupole vibration. Twenty-two states were observed lying between 2.6 and 4.0 MeV, eleven of which were observed for the first time, and 78 new transitions were placed. Two octupole states (s1/2-coupled) are identified and three more states (d3/2-coupled) are tentatively assigned using spin-parity inferences, while further h11/2-coupled states may also have been observed for the first time. Comparisons are made with state-of-the-art large-scale shell model calculations and previous observations made in this region, and systematic underestimation of the energy of the octupole vibrational states is noted. We suggest that in order to resolve the difference in predicted energies for collective and noncollective t=1 states (t is the number of nucleons breaking the Pb208 core), the effect of t=2 mixing may be reduced for octupole-coupled states. The inclusion of mixing with t=0,2,3 excitations is necessary to replicate all t=1 state energies accurately. ; 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. Support from the European Union Seventh Framework through ENSAR Contract No. 262010, the Science and Technology Facilities Council (UK), the MINECO Projects No. FPA2015-64969-P and No. FPA2017-87568-P (Spain), FWOVlaanderen (Belgium), GOA/2015/010 (BOF KU Leuven), the Excellence of Science Programme (EOS-FWO), the Interuniversity Attraction Poles Programme initiated by the Belgian Science Policy Office (BriX network P7/12), the German BMBF under Contract No. 05P18PKCIA + "Verbundprojekt 05P2018," the Polish National Science Centre under Contracts No. UMO-2015/18/M/ST2/00523 and No. UMO-2019/33/N/ST2/03023, the National Science Foundation (US) Grant No. PHY-1811855 and the Romanian IFA project CERN-RO/ISOLDE is acknowledged. P.H.R. and S.M.J. acknowledge support from the UK Department for Business, Energy and Industrial Strategy via the National Measurement Office.

5 pags., 3 figs., 1 tab. -- Open Access funded by Creative Commons Atribution Licence 4.0 ; Gamow-Teller β decay is forbidden if the number of nodes in the radial wave functions of the initial and final states is different. This Δn=0 requirement plays a major role in the β decay of heavy neutron-rich nuclei, affecting the nucleosynthesis through the increased half-lives of nuclei on the astrophysical r-process pathway below both Z=50 (for N>82) and Z=82 (for N>126). The level of forbiddenness of the Δn=1ν1g →π0g transition has been investigated from the β decay of the ground state of Hg into the single-proton-hole nucleus Tl in an experiment at the ISOLDE Decay Station. From statistical observational limits on possible γ-ray transitions depopulating the π0g state in Tl, an upper limit of 3.9×10 % was obtained for the probability of this decay, corresponding to log⁡ft>8.8 within a 95% confidence limit. This is the most stringent test of the Δn=0 selection rule to date. ; Support from the European Union seventh framework through ENSAR contract no. 262010, the Science and Technology Facilities Council through grants ST/P005314/1, ST/L005743/1 and ST/J000051/1 (UK), the MINECO projects FPA2015-64969-P, FPA2015-65035-P and FPA2017-87568-P (Spain), FWO-Vlaanderen (Belgium), GOA/2015/010 (BOF KU Leuven), the Excellence of Science programme (EOS-FWO), and the Interuniversity Attraction Poles Programme initiated by the Belgian Science Policy Office (BriX network P7/12) is acknowledged. ZsP acknowledges support by the ExtreMe Matter Institute EMMI at the GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany. PHR and SMJ ac-knowledge support from the UK Department for Business, Energy and Industrial Strategy via the National Measurement Office.

13 pags., 5 figs., 2 tabs. ; The structure of Po208 populated through the EC/β+ decay of At208 is investigated using γ-ray spectroscopy at the ISOLDE Decay Station. The presented level scheme contains 27 new excited states and 43 new transitions, as well as a further 50 previously observed γ rays which have been (re)assigned a position. The level scheme is compared to shell model calculations. Through this analysis approximately half of the β-decay strength of At208 is found to proceed via allowed decay and half via first-forbidden decay. The first-forbidden transitions predominantly populate core excited states at high excitation energies, which is qualitatively understood using shell model considerations. This mass region provides an excellent testing ground for the competition between allowed and first-forbidden β-decay calculations, important for the detailed understanding of the nucleosynthesis of heavy elements. ; The research leading to these results received funding from the European Union's Horizon 2020 research and innovation program under Grant Agreement No. 654002. Support from the European Union Seventh Framework through ENSAR Contract No. 262010, as well as the Science and Technology Facilities Council (U.K.) through Grants No. ST/P005314/1, No. ST/L005743/1, No. ST/J000051/1, No. ST/L005670/1, and No. ST/P004598/1, the German BMBF under Contract No. 05P18PKCIA and "Verbundprojekt 05P2018" as well as Spanish MINECO Grants No. FPA2015-65035- P and No. FPA2017-87568-P, FWO Vlaanderen (Belgium), GOA/2015/010 (BOF KU Leuven), the Excellence of Science Programme (EOS-FWO), the Interuniversity Attraction Poles Programme initiated by the Belgian Science Policy Office (BriX network P7/12), the Polish National Science Centre under Contracts No. UMO-2015/18/M/ST2/00523 and No. UMO-2019/33/N/ST2/03023, National Science Foundation (U.S.) Grant No. PHY1811855, and the Romanian IFA project CERN-RO/ISOLDE is acknowledged. P.H.R. acknowledges support from the U.K. Department for Business, Energy and Industrial Strategy via the National Measurement Office ; Peer reviewed

19 pags., 14 figs., 3 tabs. ; The decay of the neutron-rich and was investigated experimentally in order to provide new insights into the nuclear structure of the tin isotopes with magic proton number above the shell. The -delayed -ray spectroscopy measurement was performed at the ISOLDE facility at CERN, where indium isotopes were selectively laser-ionized and on-line mass separated. Three -decay branches of were established, two of which were observed for the first time. Population of neutron-unbound states decaying via rays was identified in the two daughter nuclei of and , at excitation energies exceeding the neutron separation energy by 1 MeV. The -delayed one- and two-neutron emission branching ratios of were determined and compared with theoretical calculations. The -delayed one-neutron decay was observed to be dominant -decay branch of even though the Gamow-Teller resonance is located substantially above the two-neutron separation energy of . Transitions following the decay of are reported for the first time, including rays tentatively attributed to . In total, six new levels were identified in on the basis of the coincidences observed in the and decays. A transition that might be a candidate for deexciting the missing neutron single-particle state in was observed in both decays and its assignment is discussed. Experimental level schemes of and are compared with shell-model predictions. Using the fast timing technique, half-lives of the , and levels in were determined. From the lifetime of the state measured for the first time, an unexpectedly large transition strength was deduced, which is not reproduced by the shell-model calculations. ; M.P.-S. acknowledges the funding support from the Polish National Science Center under Grants No. 2019/33/N/ST2/03023 and No. 2020/36/T/ST2/00547 (Doctoral scholarship ETIUDA). J.B. acknowledges support from the Universidad Complutense de Madrid under the Predoctoral Grant No. CT27/16- CT28/16. This work was partially funded by the Polish National Science Center under Grants No. 2020/39/B/ST2/02346, No. 2015/18/E/ST2/00217, and No. 2015/18/M/ST2/00523, by the Spanish government via Projects No. FPA2017-87568-P, No. RTI2018-098868-B-I00, No. PID2019-104390GB-I00, and No. PID2019-104714GB-C21, by the U.K. Science and Technology Facilities Council (STFC), the German BMBF under Contract No. 05P18PKCIA, by the Portuguese FCT under the Projects No. CERN/FIS-PAR/0005/2017, and No. CERN/FIS-TEC/0003/2019, and by the Romanian IFA Grant CERN/ISOLDE. 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. M.Str. acknowledges the funding from the European Union's Horizon 2020 research and innovation program under Grant Agreement No. 771036 (ERC CoG MAIDEN). J.P. acknowledges support from the Academy of Finland (Finland) with Grant No. 307685. Work at the University of York was supported under STFC Grants No. ST/L005727/1 and No. ST/P003885/1.

18 pags., 11 figs., 4 tabs. ; The structure of the doubly magic Sn8250132 has been investigated at the ISOLDE facility at CERN, populated both by the β-decay of In132 and β - delayed neutron emission of In133. The level scheme of Sn132 is greatly expanded with the addition of 68 γ transitions and 17 levels observed for the first time in the β decay. The information on the excited structure is completed by new γ transitions and states populated in the β-n decay of In133. Improved delayed neutron emission probabilities are obtained both for In132 and In133. Level lifetimes are measured via the advanced time-delayed βγγ(t) fast-timing method. An interpretation of the level structure is given based on the experimental findings and the particle-hole configurations arising from core excitations both from the N = 82 and Z = 50 shells, leading to positive- and negative-parity particle-hole multiplets. The experimental information provides new data to challenge the theoretical description of Sn132. ; We acknowledge the support of the ISOLDE Collaboration and the ISOLDE technical teams, and by the European Union Horizon 2020 research and innovation programme under Grant Agreement No. 654002. This work was partially funded by the Spanish government via Projects No. FPA2015- 65035-P, No. FPA-64969-P, No. FPA2017-87568-P, and No. RTI2018-098868-B-I00; the Polish National Science Center under Contracts No. UMO-2015/18/E/ST2/00217, No. UMO-2015/18/M/ST2/00523, and No. UMO2019/33/N/ST2/03023; the Portuguese FCT via CERN/FIS-NUC/0004/2015 project; the German BMBF under Contract No. 05P18PKCIA; the Romanian IFA Grant CERN/ISOLDE; and by grants from the U.K. Science and Technology Facilities Council, the Research Foundation Flanders (FWO, Belgium), the Excellence of Science program (EOS, FWO-FNRS, Belgium), and the GOA/2015/010 (BOF KU Leuven). J.B. acknowledges support from the Universidad Complutense de Madrid under the Predoctoral Grant No. CT27/16-CT28/16

12 pags., 11 figs., 3 tabs. -- Open Access funded by Creative Commons Atribution Licence 4.0 ; The occurrence of octupolar shapes in the Ba isotopic chain was recently established experimentally up to N = 90. To further extend the systematics, the evolution of shapes in the most neutron-rich members of the Z = 56 isotopic chain accessible at present, Ba-148,Ba-150, has been studied via beta decay at the ISOLDE Decay Station. This paper reports on the first measurement of the positive-and negative-parity low-spin excited states of 150Ba and presents an extension of the beta-decay scheme of Cs-148. Employing the fast timing technique, half-lives for the 2(1)(+) level in both nuclei have been determined, resulting in T-1/2 = 1.51(1) ns for Ba-148 and T-1/2 = 3.4(2) ns for Ba-150. The systematics of low-spin states, together with the experimental determination of the B(E2 : 2(+) -> 0(+)) transition probabilities, indicate an increasing collectivity in Ba148-150, towards prolate deformed shapes. The experimental data are compared to symmetry conserving configuration mixing (SCCM) calculations, confirming an evolution of increasingly quadrupole deformed shapes with a definite octupolar character. ; The IDS Collaboration acknowledges financial support from Istituto Nazionale di Fisica Nucleare, the Italian "Programmi di Ricerca Scientifica di Rilevante Interesse Nazionale" (PRIN), contract 2001024324 01302; the European Union seventh framework through ENSAR, contract 262010; the European Unions Horizon 2020 Framework research and innovation program under grant agreement 654002 (ENSAR2); the FATIMA-NuPNET network via the PRI-PIMNUP-2011-1338 project; the Romanian IFA grant CERN/ISOLDE and Romanian PN-II-RU-TE-2014-4-2003; the Spanish MINECO projects, reference numbers FPA2013- 41467-P, FPA2015-64969-P, FPA2015-65929, and FIS2015- 63770; Spanish grants FIS-2014-53434-P MINECO and Programa Ramon y Cajal 2012 No. 11420, MINECO grant IJCI-2014-19172, and the MINECO project FPA2014-52823- C2-1-P; the German BMBF under contract 05P15PKCIA, contract 05P15PKFNA, and "Verbundprojekt 05P2015," the FWO-Vlaanderen (Belgium); and the IAP Belgian Science Policy (BriX network P7/12). V.Ch. and Z.P. acknowledge support by the Polish grant of Narodowe Centrum Nauki, no. 2015/18/M/ST2/00523. ; 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.