Search

The effective prompt response function full width at half maximum, PRF FWHM of 637 ps (obtained from the prompt gamma pairs of 477 keV and 700 keV associated with the yrast 2+ state in 206Po), and 1007 ps (obtained from the Compton gamma pairs of 189 keV and 237 keV associated with the 192Os(18O,16O)194Os 2 neutron transfer reaction) were used in fitting the time difference spectra obtained from the gamma coincident pairsof 206 keV and 374 keV in a symmetrised LaBr3(Ce) associated with the gamma transitions in 192Os, using the Half-life program. The values of half-life measured by fitting these PRF FWHM of 637 ps and 1007 ps separately show an excellent agreement of 282(16) ps and 272(21) ps, respectively, which correspond to the global half-life value of 282(4) ps for the 192Os. The mean value of 277(12) ps from these two measurements was used in calculating the B(E2; IL ->IL-2) of 4233(114) e2fm4, which is equivalent to be 81(19) W.u.

The isotope selectivity of computed tomography (CT) imaging based on nuclear resonance fluorescence (NRF) transmission method using a quasi-monochromatic laser Compton scattering (LCS) gamma-ray beam in the MeV region was demonstrated at the Ultra Violet Synchrotron Orbital Radiation–III (UVSOR-III) Synchrotron Radiation Facility (Institute of Molecular Science, National Institute of Natural Science) for two enriched lead isotope rods (206Pb and 208Pb) implanted in an aluminum cylinder. Since these two rods show the same gamma-ray attenuation in atomic processes, it is impossible to differentiate between them using a standard Gamma-CT technique based on atomic attenuation of gamma rays. The LCS gamma-ray beam had a maximum energy of 5.528 MeV and an intensity of approximately 5.5 photons/s/eV at the resonance energy ( $J^{\pi } = 1^{-}$ at 5.512 MeV in 208Pb). A lead collimator with a hole diameter of 1 mm was used to define the size of the LCS gamma-ray beam at the CT target. The CT image of the 208Pb rod was selectively obtained with a 2-mm pixel size resolution, which was determined by the horizontal step size of the CT stage.

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.

A complete theoretical framework for photon elastic scattering has been implemented in GEANT4 and is validated against experimental results. The implementation covers all atomic numbers and energy range between 0.3 MeV and 20 MeV. The total elastic scattering cross section is calculated based on scattering amplitudes to account for interferences between coherent processes. New scattering amplitudes are calculated for Rayleigh scattering to extend the cross section data table and avoid interpolation and extrapolation. Validation on a significant number of test cases showed good agreement between our implementation and experimental data.

International audience; Lifetimes of the low-energy levels in Nd136, populated in the reaction Te124(O16,4n), were measured with the ROSPHERE array at the Horia Hulubei National Institute for Physics and Nuclear Engineering (IFIN-HH), Bucharest-Magurele. The data were analyzed using the recoil distance Doppler shift method, and, in the cases where lifetimes were τ⩽1 ps, Doppler attenuation effects were taken into account. The deduced electromagnetic transition probabilities are discussed in the framework of the five-dimensional collective Hamiltonian (5DCH) theoretical model implemented with the D1S Gogny force, and detailed systematics of several observables in the even-even Nd isotopic chain are presented that highlight the transitional character of the neutron-deficient Nd isotopes. The 5DCH predictions are in overall good agreement with the present experimental results.

An extended investigation of the low-spin structure of the Ni65 nucleus was performed at the Institut Laue-Langevin, Grenoble, France, via the neutron capture reaction Ni64(n,γ)Ni65, using the Fission Product Prompt Gamma-Ray Spectrometer High-Purity Ge array. The level scheme of Ni65 was significantly expanded, with two new levels and 87 newly found transitions. Angular correlation analyses were also performed, allowing us to assign spins and parities for a number of states and to determine multipolarity mixing ratios for selected γ transitions. The low-energy part of the experimental level scheme (up to about 1.4 MeV) was compared with Monte Carlo shell-model calculations, which predict spherical shapes for all states, apart from the 9/2+ and the second excited 1/2- states of oblate deformation., SCOPUS: ar.j, info:eu-repo/semantics/published

Medium and high spin states of the Y96 nucleus, located in the shape-coexistence region near Z=40 and N=60, were populated in thermal-neutron-induced fission of U233 and U235 targets, diluted in a scintillator. γ rays were measured with the FIssion Product Prompt γ-ray Spectrometer (FIPPS) high-purity germanium (HPGe) detector array, using double and triple γ-ray coincidence techniques and taking advantage of the efficient fission tag provided by the scintillating target material. A complex level scheme, extending up to 5.2 MeV and including excitations above the 8+β-decaying isomer, was investigated, and firm spin and parity assignments were given to a number of states, on the basis of angular correlation analysis and considerations on the γ-decay patterns. While the structures built on the 0− ground state and the 8+ isomer show irregular patterns typical for spherical shapes, the (6+) isomeric state at 1655 keV [with half-life of 181(9) ns], and the rotational band built on it [with spin-parity values between (6+) and (9+)], can be explained by Hartree-Fock-Bogoliubov calculations, if an oblate deformation is assumed. This is the first observation of a deformed structure in an N=57 isotone, lying three neutrons away from the N=60 line. An important finding is also the 115-keV transition which connects the (6+) 181(9)-ns isomer to the β-decaying 8+ spherical isomer, allowing us to firmly place the latter at 1541 keV excitation energy. This may be relevant for calculations of electron and antineutrino spectra from fission of actinides, for which Y96 is a prominent product.

The excitation spectra in the deformed nucleus $^{158}\mathrm{Gd}$ have been studied with high energy resolution for the extended spin and parity range by means of the $(p, t)$ reaction using the Q3D spectrograph facility at the Munich Tandem accelerator. The angular distributions of tritons were measured for more than 200 excited states seen in the triton spectra up to 4.3 MeV. Spins and parities of states were assigned by comparison of experimental angular distributions with the calculated ones with the help of the chuck3 code. Differential cross-section calculations for multistep processes were required in order to make spin assignments for spins greater than zero and so that different pathways were inferred for different states. In addition to the previously studied multiple ${0}^{+}$ excitations, in this study, the assignments for levels with higher spins are the following: 95 for ${2}^{+}$ states, 64 for ${4}^{+}$ states, 14 for ${6}^{+}$ states, and about 20 for negative parity states. Selected sequences of states with energies following $I(I+1)$ systematics and suitable cross section variations are treated as rotational bands. An analysis of the moments of inertia defined for these bands is carried out. This high number of excited states in a deformed nucleus, close to a complete level scheme, constitutes a very good ground to check models of nuclear structure. The large ensembles of states with the same spin-parity offer unique opportunities for statistical analysis. Such an analysis for the ${0}^{+}$ and ${2}^{+}$ states sequences, for all $K$ values and for well-determined projections $K$ of the angular momentum is performed. The obtained data may indicate on a $K$ symmetry breaking. Experimental data are compared with interacting boson model (IBM) calculations using the $spdf$ version of the model. The energies of the low-lying levels, the transition probabilities in the first bands, and the distribution in transfer intensity of the ${0}^{+}$ states are calculated and compared with experiment.

The β decay of 207Hg into the single-proton-hole nucleus 207Tl has been studied through γ-ray spectroscopy at the ISOLDE Decay Station (IDS) with the aim of identifying states resulting from coupling of the πs−11/2, πd−13/2, and πh−111/2 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 208Pb 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 $^{7}\mathrm{Li}(\ensuremath{\gamma},t)^{4}\mathrm{He}$ ground state cross section was measured for the first time using monoenergetic $\ensuremath{\gamma}$ rays with energies between 4.4 and 10 MeV at the High Intensity Gamma-ray Source. The reaction is important for the primordial Li problem and for testing our understanding of the mirror $\ensuremath{\alpha}$-capture reactions $^{3}\mathrm{H}(\ensuremath{\alpha},\ensuremath{\gamma})^{7}\mathrm{Li}$ and $^{3}\mathrm{He}(\ensuremath{\alpha},\ensuremath{\gamma})^{7}\mathrm{Be}$. Although over the last 30 years most measurements of the $^{3}\mathrm{H}(\ensuremath{\alpha},\ensuremath{\gamma})^{7}\mathrm{Li}$ reaction have concentrated in an energy range below ${E}_{\ensuremath{\gamma}}=3.65$ MeV, measurements at higher energies could potentially restrict the extrapolation to astrophysically important energies. The experimental arrangement for measuring the $^{7}\mathrm{Li}(\ensuremath{\gamma},t)^{4}\mathrm{He}$ reaction included a large-area silicon detector array and several beam characterization instruments. The experimental astrophysical $S$ factor of $^{3}\mathrm{H}(\ensuremath{\alpha},\ensuremath{\gamma})$ calculated from the present data was fitted using the $R$-matrix formalism. The results are in disagreement with previous experimental measurements in the same energy range but the extrapolated $S$ factor agrees with the potential model calculation and lower energy experimental data.

This paper reports cross-section measurements of the ($n,{n}^{\ensuremath{'}}$) and ($p,{p}^{\ensuremath{'}}$) reactions on $^{16}\mathrm{O}$ and $^{28}\mathrm{Si}$ at Geel Electron Linear Accelerator and at the 9-MV Tandem Accelerator of Horia Hulubei National Institute for Physics and Nuclear Engineering, respectively. The main purpose was to measure the neutron- and proton-induced inelastic $\ensuremath{\gamma}$-production cross sections for all observed transitions in $^{16}\mathrm{O}$ and $^{28}\mathrm{Si}$, followed by the calculation of the corresponding total inelastic cross section. The results are compared with theoretical calculations performed using the talys 1.9 code, evaluated nuclear data, and previously reported experimental data. The broader goal of this work is to study whether and to what extent the neutron-induced inelastic cross sections of these nuclei can be inferred from those obtained using suitable charged particle reactions. We show that, by making use of the formal similarities between the neutron- and the proton-target optical model potentials and isospin symmetry in mirror nuclei, one can develop a procedure that combines experimental proton-induced inelastic cross sections with theoretical calculations to infer neutron inelastic cross sections. For $^{16}\mathrm{O}$ and $^{28}\mathrm{Si}$, the precision associated with this procedure is around 10--20% for most of the incident energy range.

The level structure of La-130 has been investigated using the (121)sb(C-12, 3n) reaction with the ROSPHERE array at IFIN-HH, Bucharest. the level scheme was significantly extended with the observation of 45 new states and 100 new transitions. Several band structures have been identified and a clear connection with the lower-lying states has been established. A lifetime of tau = 3.6(2) ns has been measured for the 346-keV 6(-) state by the in-beam fast timing technique. the lifetimes of 18 high-spin states have been determined by applying the Doppler-shift attenuation method. the deformations derived from the experimental B(E2) transition strengths indicate distinct coexisting shapes at high spins in La-130. the experimental properties of both low- and high-spin states were compared with theoretical calculations performed in the frame of the two-quasiparticles-plus-rotor model. Two new negative-parity decoupled bands, with a deduced quadrupole deformation beta(2) = 0.150(15), were interpreted by coupling the proton in the 1/2[550] and 3/2[541] orbitals with the odd neutron occupying mainly the low-Omega orbitals from the d(3/2) and 5(1/2) states. A quadrupole deformation beta(2) = 0.220(17) was derived for a newly identified positive-parity decoupled band. This enhanced deformation was attributed to the involvement in the band configuration of the Omega = 1/2 (f(7/2), h(9/2)) intruder neutron orbital. the multiparticle configuration pi g(7/2)(h(11/2))(2) circle times nu (h(11/2)) was assigned to a high-spin negative-parity dipole band, based on the comparison of the experimental B(M1) transition strengths with values calculated by applying the geometrical model of Donau and Frauendorf., Ministry of Education and Research, Romania [PN-19-06-01-02], Authors are thankful to the FN Tandem staff of the Horia Hulubei National Institute of Physics and Nuclear Engineering for the good quality delivered beam. This work was supported by the Ministry of Education and Research, Romania, Contract No. PN-19-06-01-02.

Two analysis methods for $$\textit{Z}_\mathrm{eff}$$ evaluation were explored using both experimental and simulated gamma-ray attenuation data. Using particle-capture reactions on composite targets to generate multi-monoenergetic gamma rays between 1 and 12 MeV, we demonstrate the advantage of using neural networks for effective Z evaluation of shielded materials in single-pixel measurements. Furthermore, we extend the analysis to 2D processing of transmission radiography and by using Geant4-simulated data we prove the superiority of artificial neural networks in terms of image quality and material discrimination against classical methods.

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

Bremsstrahlung based dual-energy attenuation is the most widely used methodology for high-energy cargo inspection systems and Z e f f mapping. Currently, the inspection systems do not exploit the spectroscopic component of the transmitted spectrum, relying mostly on energy integrated attenuation signals. In this work, we propose a neural-network based approach to determine Z e f f from energy resolved transmitted spectra using single high-energy attenuations. The neural-network approach based on a regression algorithm was benchmarked against the dual-energy attenuation method. The evaluation is made using Geant4 simulated data covering the full range of Z values and indicates potential improvements in terms of imaging speed and Z e f f discriminating power for the neural-network based approach.

WOS: 000450997800001, The lifetimes of the excited states belonging to the chiral-candidate doublet bands built on the pi h(11/2) circle times vh(11/12)(-1) configuration in La-130 have been measured by applying the Doppler-shift attenuation method and the in-beam fast timing technique. Excited states were populated in the Sb-121(C-12, 3n) reaction at a bombarding energy of 54 MeV. The 7(+) bandhead of the yrast band was identified as an isomeric state with a lifetime of tau(7(+)) = 0.38(7) ns Similar reduced transition probabilities B(M1) and B(E2) were found for the states with the same spin in the partner bands. The results revealed an even-odd spin dependence in the B(E2) values, whereas the B (M1) values vary nearly monotonically with increasing spin. The experimental properties of the doublet bands in La-130 are compared with theoretical calculations done in the frame of the two-quasiparticles-plus-triaxial-rotor model. The static chirality is not supported by the obtained data; however, chiral vibrations cannot be excluded., Scientific and Technological Research Council of Turkey (TUBTAK) [BIDEB-2219], Authors are thankful to the FN Tandem staff of the Horia Hulubei National Institute of Physics and Nuclear Engineering for the good quality of the delivered beam. S.A. acknowledges financial support from the Scientific and Technological Research Council of Turkey (TUBTAK) BIDEB-2219 Postdoctoral Research program.

The structure of $^{34}$Si was studied through $\gamma$ spectroscopy separately in the $\beta^-$ decays of $^{34}$Mg and $^{34}$Al at the ISOLDE facility of CERN. Different configurations in $^{34}$Si were populated independently from the two recently identified $\beta$-decaying states in $^{34}$Al having spin-parity assignments $J^\pi = 4^-$ dominated by the normal configuration $\pi (d_{5/2})^{-1} \otimes \nu (f_{7/2})$ and $J^\pi = 1^+$ by the intruder configuration $\pi (d_{5/2})^{-1} \otimes \nu (d_{3/2})^{-1}(f_{7/2})^{2}$. The paper reports on spectroscopic properties of $^{34}$Si such as an extended level scheme, spin and parity assignments based on log($ft$) values and $\gamma$-ray branching ratios, absolute $\beta$ 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 $^{34}$Si. Large scale shell-model calculations using the {\sc 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 {\sc sdpf-u-mix}, the $N=20$ shell gap, the level of mixing between normal and intruder configurations for the 0$_1^+$, 0$_2^+$ and 2$_1^+$ states and the absence of triaxial deformation in $^{34}$Si.

Excited states in the $^{158}\mathrm{Eu}$ nucleus have been determined with the $^{160}\mathrm{Gd}(d,\ensuremath{\alpha})^{158}\mathrm{Eu}$ reaction, studied at an incident energy of 18.0 MeV with the Munich tandem and Q3D spectrograph. More than 50 excited states have been determined up to 1.6 MeV excitation, some of them corresponding to states previously observed in the ${\ensuremath{\beta}}^{\ensuremath{-}}$ decay of $^{158}\mathrm{Sm}$. The number of levels found in this nucleus at low excitation energies follows the systematic trend of the level densities in the other isotopes with mass 152--156.

Compton γ -ray sources have been in operation for over 30 years with new facilities being under construction or proposed. The gamma beam system under implementation at the Extreme Light Infrastructure - Nuclear Physics facility in Romania will deliver brilliant γ -ray beams with energies up to 19.5 MeV. Several instruments for measuring the parameters of the γ -ray beam are under development at ELI-NP. One of these instruments based on a High Purity Germanium detector is routinely used for beam energy measurements at other facilities. Here we investigate the use of a High Purity Germanium detector to continuously monitor the intensity of the ELI-NP gamma beam by measuring the inelastic scattering of photons. This method relies on both experimental and simulated data and it has been successfully tested during a recent experiment at the High Intensity γ -ray Source facility.

Excited states in Sn-133 were investigated through the beta decay of In-133 at the ISOLDE facility. The ISOLDE Resonance Ionization Laser Ion Source (RILIS) provided isomer-selective ionization for In-133, allowing us to study separately, and in detail, the beta-decay branch of In-133 J(pi)= (9/2(+)) ground state and its J(pi) = (1/2(-)) isomer.Thanks to the large spin difference of the two beta-decaying states of In-133, it is possible to investigate separately the lower and higher spin states in the daughter, Sn-133, and thus to probe independently different single-particle and single-hole levels. We report here new gamma transitions observed in the decay of In-133, including those assigned to the deexcitation of the neutron-unbound states.

We report on the development of custom Front-End Electronics (FEE) dedicated to large area SiPM arrays for γ -ray spectroscopy applications in high counting rate conditions. Two types of commercially available 8 × 8 arrays of 6 × 6 mm 2 Silicon Photomultipliers (SiPM) and a quasi-circular array of 30 SiPM cells were coupled to dedicated Front End Electronics (FEE) boards and tested in combination with LaBr 3 (Ce) crystals. Energy resolution measurements were taken with standard calibration radioactive sources (60Co, 152Eu and 56 Co) while the timing response was studied in comparison with industry standard photomultiplier tubes . The energy resolution measured in this setup was down to 3.09(9)% at 661 keV, while the best timing resolution measured was 222.3(22) ps. Finally, the design of a SiPM based γ -ray detector, dedicated to fast-timing applications, is presented.

A customizable and cost-efficient particle-detection system for transfer experiments at ROSPHERE has been designed and tested. Results from the commissioning experiment employing the 2 n -transfer reaction 94Zr(18O, 16O)96Zr are presented and discussed. The device allows for an efficient suppression of contributions from fusion-evaporation reactions and an improvement of the peak-to-background ratio by about one order of magnitude. The construction, characteristics, and performance are presented and further developments are outlined.

International audience; A proton inelastic scattering experiment on a 57Fe target was performed at the 9 MV TANDEM facility of Horia Hulubei-National Institute of Physics and Nuclear Engineering, Bucharest-Măgurele, Romania. The purpose was to determine the γ-production cross sections of the transitions observed in the 57Fe(p, p’γ)57Fe reaction. The detection system consisted of 4 HPGe detectors for detection and a Faraday cup for beam integration. The proton energy was varied from 5 to 16 MeV, in 1-MeV steps. In the current analysis, experimental cross sections were determined only for the high-volume detectors, placed at 110◦ and 150◦ with respect to the beam axis. This work presents the data analysis procedure and the preliminary experimental cross sections for the most intense transitions decaying from the first seven excited states in 57Fe. The results are compared with TALYS 1.9 theoretical calculations performed using default input parameters.

6 pags., 3 figs. -- Open Access funded by Creative Commons Atribution Licence 4.0. -- Presented at the XXXV Mazurian Lakes Conference on Physics, Piaski, Poland, September 3–9, 2017., Excited states in the neutron-rich isotope 133Sn were studied via the ß decay of 133In. Isomer selective ionization using the ISOLDE RILIS enabled the ß decays of 133Ings (I¿ = 9=2+) and 133mIn (II¿ = 1=2-) to be studied independently for the first time. A description of the experimental setup at the ISOLDE Decay Station is presented together with preliminary results from the experiment., This work was supported in part by the National Science Centre, Poland (NCN) under contracts No. UMO-2015/18/E/ST2/00217 and No. UMO- 2015/18/M/ST2/00523, by the Spanish MINECO via FPA2015-65035-P project and by the Portuguese FCT via CERN/FIS-NUC/0004/2015 project.

A search for shape isomers in the ^{66}Ni nucleus was performed, following old suggestions of various mean-field models and recent ones, based on state-of-the-art Monte Carlo shell model (MCSM), all considering ^{66}Ni as the lightest nuclear system with shape isomerism. By employing the two-neutron transfer reaction induced by an ^{18}O beam on a ^{64}Ni target, at the sub-Coulomb barrier energy of 39 MeV, all three lowest-excited 0^{+} states in ^{66}Ni were populated and their γ decay was observed by γ-coincidence technique. The 0^{+} states lifetimes were assessed with the plunger method, yielding for the 0_{2}^{+}, 0_{3}^{+}, and 0_{4}^{+} decay to the 2_{1}^{+} state the B(E2) values of 4.3, 0.1, and 0.2 Weisskopf units (W.u.), respectively. MCSM calculations correctly predict the existence of all three excited 0^{+} states, pointing to the oblate, spherical, and prolate nature of the consecutive excitations. In addition, they account for the hindrance of the E2 decay from the prolate 0_{4}^{+} to the spherical 2_{1}^{+} state, although overestimating its value. This result makes ^{66}Ni a unique nuclear system, apart from ^{236,238}U, in which a retarded γ transition from a 0^{+} deformed state to a spherical configuration is observed, resembling a shape-isomerlike behavior.

The properties of excited states in the neutron-rich nucleus 194Os have been investigated using the 192Os(18O,16O)194Os reaction with an 80 MeV beam provided by the IFIN-HH Laboratory, Bucharest. Discrete γ -ray decays from excited states have been measured using the hybrid HPGe-LaBr3(Ce) array RoSPHERE. The current work identifies a number of previously unreported low-lying nonyrast states in 194Os as well as the first measurement of the half-life of the yrast 2+ state of 302(50) ps. This is equivalent to a B(E2 : 2+ → 0+) = 45(16) W.u. and intrinsic quadrupole deformation of βeff = 0.14(1). The experimental results are compared with Hartree-Fock-Bogoliubov–interacting-boson-model calculations and are consistent with a reduction in a quadrupole collectivity in Os isotopes with increasing neutron number.

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.

A (p, p′γ ) experiment was performed at the Tandem accelerator of IFIN-HH (Bucharest) with the purpose of measuring the proton inelastic cross-sections on 16 O and 28 Si. The goal was to investigate to which extent the neutron cross-sections on these nuclei can be inferred from those obtained with charged particles (i.e., protons). In doing so, we are trying to exploit the isospin symmetry by taking under consideration that the chosen targets are N = Z nuclei and, consequently, two mirror nuclei are formed in the (p ,p ′) and (n ,n ′) reactions. The experimental setup consisted of two HPGe detectors with 100% relative efficiency placed at 110∘ and 150∘ relative to the direction of the incident proton beam. The incident protons, which had energies ranging from 6 up to 17 MeV, were scattered on a thick quartz (SiO2 ) target. A Faraday cup was used to integrate the beam current, thus allowing an absolute determination of the γ production cross sections. We will briefly describe the data analysis procedure, the experimental particularities and difficulties and some preliminary results of the γ production cross sections for the most intense transitions both in 16 O and 28 Si.

The lifetime $\ensuremath{\tau}({0}_{2}^{+})$ of $^{152}\mathrm{Gd}$ has been measured using fast electronic scintillation timing (FEST) with an array of high-purity germanium (HPGe) and cerium-doped lanthanum bromide (${\mathrm{LaBr}}_{3}$) detectors. $^{152}\mathrm{Gd}$ was produced via an $(\ensuremath{\alpha},n)$ reaction on a gold backed $^{149}\mathrm{Sm}$ target. The measured lifetime of $\ensuremath{\tau}({0}_{2}^{+})=96(6)\phantom{\rule{4pt}{0ex}}\mathrm{ps}$ corresponds to a reduced transition strength of $B(E2;{0}_{2}^{+}\ensuremath{\rightarrow}{2}_{1}^{+})=111(7)$ W.u. and an $E0$ transition strength of ${\ensuremath{\rho}}^{2}(E0)=39(3)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$ to the ground state. This result provides experimental support for the validity of a correlation that would be a novel indicator for a quantum phase transition (QPT).

M. V. et al. ; 14 págs.; 10 figs.; 6 tabs., Beta-delayed proton emission from Mg has been measured at ISOLDE, CERN, with the ISOLDE Decay Station (IDS) setup including both charged-particle and gamma-ray detection capabilities. A total of 27 delayed proton branches were measured including seven so far unobserved. An updated decay scheme, including three new resonances above the proton separation energy in Na and more precise resonance energies, is presented. Beta-decay feeding to two resonances above the Isobaric Analogue State (IAS) in Na is observed. This may allow studies of the 4032.9(2.4)keV resonance in Ne through the beta decay of Mg, which is important for the astrophysically relevant reaction O(α,γ)Ne. Beta-delayed protons were used to obtain a more precise value for the half-life of Mg, 91.4(1.0)ms. © SIF, Springer-Verlag Berlin Heidelberg, 2016, This work has been supported by the European Commision within the Seventh Framework Programme “European Nuclear Science and Applications Research”, contract no. 262010 (ENSAR), by the Spanish research agency under number FPA2012- 32443, FPA2015-64969-P and FPA2015-65035-P and by the Romanian IFA Grant CERN/ISOLDE. The authors also acknowledge the support of the Danish Natural Science Research Council, the United Kingdom Science and Technology Facilities Council, the German BMBF under grants 05P12PKFNE and 05P15PKCIA and the German Verbundprojekt 05P20015- ISOLDE

I. Marroquín et al. ; 8 págs.; 6 fgis.; 1 tab. ; Presented at the XXXIV Mazurian Lakes Conference on Physics, Piaski, Poland, September 6–13, 2015., A multi-particle decay experiment was successfully performed at the ISOLDE Decay Station. In this new permanent station, devoted to -decay studies, the novel MAGISOL Si-Plugin Chamber was installed to study the exotic decay modes of the proton drip-line nucleus 31Ar. The motivation was to search for 3p and 3p channels, as well as to provide information on resonances in 30S and 29P relevant for the astrophysical rp-process. Description of the experimental set-up and preliminary results are presented., This work is supported by the Spanish Funding Agency under Project No. FPA2012-32443 and FPI grant BES-2013-066348.

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.

Absolute cross sections for the 86 Sr(α,n)89 Zr reaction at energies close to the Gamow window are reported. Three thin SrF2 targets were irradiated using the 9 MV Tandem facility in IFIN-HH Bucharest that delivered α beams for the activation process. Two high-purity Germanium detectors were used to measure the induced activity of 89 Zr in a low background environment. The experimental results are in very good agreement with Hauser-Feshbach statistical model calculations performed with the TALYS code.