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2.	Overview of the JET results 2015 Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 55:10 Tidskriftsartikel (refereegranskat)
3.	Abel, I, et al. (författare) Overview of the JET results with the ITER-like wall 2013 Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 53:10, s. 104002- Tidskriftsartikel (refereegranskat)abstract Following the completion in May 2011 of the shutdown for the installation of the beryllium wall and the tungsten divertor, the first set of JET campaigns have addressed the investigation of the retention properties and the development of operational scenarios with the new plasma-facing materials. The large reduction in the carbon content (more than a factor ten) led to a much lower Z(eff) (1.2-1.4) during L- and H-mode plasmas, and radiation during the burn-through phase of the plasma initiation with the consequence that breakdown failures are almost absent. Gas balance experiments have shown that the fuel retention rate with the new wall is substantially reduced with respect to the C wall. The re-establishment of the baseline H-mode and hybrid scenarios compatible with the new wall has required an optimization of the control of metallic impurity sources and heat loads. Stable type-I ELMy H-mode regimes with H-98,H-y2 close to 1 and beta(N) similar to 1.6 have been achieved using gas injection. ELM frequency is a key factor for the control of the metallic impurity accumulation. Pedestal temperatures tend to be lower with the new wall, leading to reduced confinement, but nitrogen seeding restores high pedestal temperatures and confinement. Compared with the carbon wall, major disruptions with the new wall show a lower radiated power and a slower current quench. The higher heat loads on Be wall plasma-facing components due to lower radiation made the routine use of massive gas injection for disruption mitigation essential.
4.	Romanelli, F, et al. (författare) Overview of the JET results 2011 Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 51:9 Tidskriftsartikel (refereegranskat)abstract Since the last IAEA Conference JET has been in operation for one year with a programmatic focus on the qualification of ITER operating scenarios, the consolidation of ITER design choices and preparation for plasma operation with the ITER-like wall presently being installed in JET. Good progress has been achieved, including stationary ELMy H-mode operation at 4.5 MA. The high confinement hybrid scenario has been extended to high triangularity, lower ρand to pulse lengths comparable to the resistive time. The steady-state scenario has also been extended to lower ρand ν*and optimized to simultaneously achieve, under stationary conditions, ITER-like values of all other relevant normalized parameters. A dedicated helium campaign has allowed key aspects of plasma control and H-mode operation for the ITER non-activated phase to be evaluated. Effective sawtooth control by fast ions has been demonstrated with3He minority ICRH, a scenario with negligible minority current drive. Edge localized mode (ELM) control studies using external n = 1 and n = 2 perturbation fields have found a resonance effect in ELM frequency for specific q95values. Complete ELM suppression has, however, not been observed, even with an edge Chirikov parameter larger than 1. Pellet ELM pacing has been demonstrated and the minimum pellet size needed to trigger an ELM has been estimated. For both natural and mitigated ELMs a broadening of the divertor ELM-wetted area with increasing ELM size has been found. In disruption studies with massive gas injection up to 50% of the thermal energy could be radiated before, and 20% during, the thermal quench. Halo currents could be reduced by 60% and, using argon/deuterium and neon/deuterium gas mixtures, runaway electron generation could be avoided. Most objectives of the ITER-like ICRH antenna have been demonstrated; matching with closely packed straps, ELM resilience, scattering matrix arc detection and operation at high power density (6.2 MW m-2) and antenna strap voltages (42 kV). Coupling measurements are in very good agreement with TOPICA modelling. © 2011 IAEA, Vienna.
5.	Collaboration, The PANDA, et al. (författare) Feasibility studies of time-like proton electromagnetic form factors at PANDA at FAIR 2016 Ingår i: European Physical Journal A. - : Springer Publishing Company. - 1434-6001 .- 1434-601X. ; 52:10 Tidskriftsartikel (refereegranskat)abstract Simulation results for future measurements of electromagnetic proton form factors at P ¯ ANDA (FAIR) within the PandaRoot software framework are reported. The statistical precision with which the proton form factors can be determined is estimated. The signal channel p¯ p→ e+e- is studied on the basis of two different but consistent procedures. The suppression of the main background channel, i.e.p¯ p→ π+π-, is studied. Furthermore, the background versus signal efficiency, statistical and systematical uncertainties on the extracted proton form factors are evaluated using two different procedures. The results are consistent with those of a previous simulation study using an older, simplified framework. However, a slightly better precision is achieved in the PandaRoot study in a large range of momentum transfer, assuming the nominal beam conditions and detector performance.
6.	Kapelios, CJ, et al. (författare) Sacubitril/valsartan eligibility and outcomes in the ESC-EORP-HFA Heart Failure Long-Term Registry: bridging between European Medicines Agency/Food and Drug Administration label, the PARADIGM-HF trial, ESC guidelines, and real world 2019 Ingår i: European journal of heart failure. - : Wiley. - 1879-0844 .- 1388-9842. ; 21:11, s. 1383-1397 Tidskriftsartikel (refereegranskat)
7.	Singh, B., et al. (författare) Feasibility study for the measurement of pi N transition distribution amplitudes at (P)over-barANDA in (P)over-barp -> J/psi pi(0) 2017 Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 95:3 Tidskriftsartikel (refereegranskat)abstract The exclusive charmonium production process in (P) over barp annihilation with an associated pi 0 meson (p) over barp -> J/psi pi(0) is studied in the framework of QCD collinear factorization. The feasibility of measuring this reaction through the J/psi -> e(+) e(-) decay channel with the AntiProton ANnihilation at DArmstadt ((P) over bar ANDA) experiment is investigated. Simulations on signal reconstruction efficiency as well as the background rejection from various sources including the (P) over barp -> pi(+)pi(-)pi(0) and (p) over barp -> J/psi pi(0)pi(0) reactions are performed with PANDAROOT, the simulation and analysis software framework of the (P) over bar ANDA experiment. It is shown that the measurement can be done at (P) over bar ANDA with significant constraining power under the assumption of an integrated luminosity attainable in four to five months of data taking at the maximum design luminosity.
8.	Singh, B., et al. (författare) Study of doubly strange systems using stored antiprotons 2016 Ingår i: Nuclear Physics A. - : Elsevier. - 0375-9474 .- 1873-1554. ; 954, s. 323-340 Tidskriftsartikel (refereegranskat)abstract Bound nuclear systems with two units of strangeness are still poorly known despite their importance for many strong interaction phenomena. Stored antiprotons beams in the GeV range represent an unparalleled factory for various hyperon-antihyperon pairs. Their outstanding large production probability in antiproton collisions will open the floodgates for a series of new studies of systems which contain two or even more units of strangeness at the PANDA experiment at FAIR. For the first time, high resolution gamma-spectroscopy of doubly strange Lambda Lambda-hypernuclei will be performed, thus complementing measurements of ground state decays of Lambda Lambda-hypernuclei at J-PARC or possible decays of particle unstable hypernuclei in heavy ion reactions. High resolution spectroscopy of multistrange Xi(-) -atoms will be feasible and even the production of Omega(-) -atoms will be within reach. The latter might open the door to the vertical bar S vertical bar = 3 world in strangeness nuclear physics, by the study of the hadronic Omega(-) -nucleus interaction. For the first time it will be possible to study the behavior of Xi(+) in nuclear systems under well controlled conditions.
9.	Dinklage, A, et al. (författare) Magnetic configuration effects on the Wendelstein 7-X stellarator 2018 Ingår i: NATURE PHYSICS. - 1745-2473. ; 14:8, s. 855- Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
10.	Akkoyun, S., et al. (författare) AGATA - Advanced GAmma Tracking Array 2012 Ingår i: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - : Elsevier BV. - 0168-9002 .- 0167-5087 .- 1872-9576. ; 668, s. 26-58 Tidskriftsartikel (refereegranskat)abstract The Advanced GAmma Tracking Array (AGATA) is a European project to develop and operate the next generation γ-ray spectrometer. AGATA is based on the technique of γ-ray energy tracking in electrically segmented high-purity germanium crystals. This technique requires the accurate determination of the energy, time and position of every interaction as a γ ray deposits its energy within the detector volume. Reconstruction of the full interaction path results in a detector with very high efficiency and excellent spectral response. The realisation of γ-ray tracking and AGATA is a result of many technical advances. These include the development of encapsulated highly segmented germanium detectors assembled in a triple cluster detector cryostat, an electronics system with fast digital sampling and a data acquisition system to process the data at a high rate. The full characterisation of the crystals was measured and compared with detector- response simulations. This enabled pulse-shape analysis algorithms, to extract energy, time and position, to be employed. In addition, tracking algorithms for event reconstruction were developed. The first phase of AGATA is now complete and operational in its first physics campaign. In the future AGATA will be moved between laboratories in Europe and operated in a series of campaigns to take advantage of the different beams and facilities available to maximise its science output. The paper reviews all the achievements made in the AGATA project including all the necessary infrastructure to operate and support the spectrometer. © 2011 Elsevier B.V. All rights reserved.
11.	Klionsky, Daniel J., et al. (författare) Guidelines for the use and interpretation of assays for monitoring autophagy 2012 Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544 Forskningsöversikt (refereegranskat)abstract In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
12.	Stroth, U., et al. (författare) Progress from ASDEX Upgrade experiments in preparing the physics basis of ITER operation and DEMO scenario development 2022 Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 62:4 Tidskriftsartikel (refereegranskat)abstract An overview of recent results obtained at the tokamak ASDEX Upgrade (AUG) is given. A work flow for predictive profile modelling of AUG discharges was established which is able to reproduce experimental H-mode plasma profiles based on engineering parameters only. In the plasma center, theoretical predictions on plasma current redistribution by a dynamo effect were confirmed experimentally. For core transport, the stabilizing effect of fast ion distributions on turbulent transport is shown to be important to explain the core isotope effect and improves the description of hollow low-Z impurity profiles. The L-H power threshold of hydrogen plasmas is not affected by small helium admixtures and it increases continuously from the deuterium to the hydrogen level when the hydrogen concentration is raised from 0 to 100%. One focus of recent campaigns was the search for a fusion relevant integrated plasma scenario without large edge localised modes (ELMs). Results from six different ELM-free confinement regimes are compared with respect to reactor relevance: ELM suppression by magnetic perturbation coils could be attributed to toroidally asymmetric turbulent fluctuations in the vicinity of the separatrix. Stable improved confinement mode plasma phases with a detached inner divertor were obtained using a feedback control of the plasma β. The enhanced D α H-mode regime was extended to higher heating power by feedback controlled radiative cooling with argon. The quasi-coherent exhaust regime was developed into an integrated scenario at high heating power and energy confinement, with a detached divertor and without large ELMs. Small ELMs close to the separatrix lead to peeling-ballooning stability and quasi continuous power exhaust. Helium beam density fluctuation measurements confirm that transport close to the separatrix is important to achieve the different ELM-free regimes. Based on separatrix plasma parameters and interchange-drift-Alfvén turbulence, an analytic model was derived that reproduces the experimentally found important operational boundaries of the density limit and between L- and H-mode confinement. Feedback control for the X-point radiator (XPR) position was established as an important element for divertor detachment control. Stable and detached ELM-free phases with H-mode confinement quality were obtained when the XPR was moved 10 cm above the X-point. Investigations of the plasma in the future flexible snow-flake divertor of AUG by means of first SOLPS-ITER simulations with drifts activated predict beneficial detachment properties and the activation of an additional strike point by the drifts.
13.	Valiente-Dobon, J. J., et al. (författare) Conceptual design of the AGATA 2 pi array at LNL 2023 Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 1049 Tidskriftsartikel (refereegranskat)abstract The Advanced GAmma Tracking Array (AGATA) has been installed at Laboratori Nazionali di Legnaro (LNL), Italy. In this installation, AGATA will consist, at the beginning, of 13 AGATA triple clusters (ATCs) with an angular coverage of 1n,and progressively the number of ATCs will increase up to a 2 pi angular coverage. This setup will exploit both stable and radioactive ion beams delivered by the Tandem-PIAVE-ALPI accelerator complex and the SPES facility. The new implementation of AGATA at LNL will be used in two different configurations, firstly one coupled to the PRISMA large-acceptance magnetic spectrometer and lately a second one at Zero Degrees, along the beam line. These two configurations will allow us to cover a broad physics program, using different reaction mechanisms, such as Coulomb excitation, fusion-evaporation, transfer and fission at energies close to the Coulomb barrier. These setups have been designed to be coupled with a large variety of complementary detectors such as charged particle detectors, neutron detectors, heavy-ion detectors, high-energy gamma-ray arrays, cryogenic and gasjet targets and the plunger device for lifetime measurements. We present in this paper the conceptual design, characteristics and performance figures of this implementation of AGATA at LNL.
14.	Meyer, H., et al. (författare) Overview of physics results from MAST 2009 Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 49:10, s. 104017- Tidskriftsartikel (refereegranskat)abstract Several improvements to the MAST plant and diagnostics have facilitated new studies advancing the physics basis for ITER and DEMO, as well as for future spherical tokamaks (STs). Using the increased heating capabilities P-NBI <= 3.8 MW H-mode at I-P = 1.2 MA was accessed showing that the energy confinement on MAST scales more weakly with I-P and more strongly with B-t than in the ITER IPB98(y, 2) scaling. Measurements of the fuel retention of shallow pellets extrapolate to an ITER particle throughput of 70% of its original designed total throughput capacity. The anomalous momentum diffusion, chi(phi), is linked to the ion diffusion, chi(i), with a Prandtl number close to P-phi approximate to chi(phi)/chi(i) approximate to 1, although chi(i) approaches neoclassical values. New high spatial resolution measurements of the edge radial electric field, E-r, show that the position of steepest gradients in electron pressure and E-r (i.e. shearing rate) are coincident, but their magnitudes are not linked. The T-e pedestal width on MAST scales with root beta(ped)(pol) rather than rho(pol). The edge localized mode (ELM) frequency for type-IV ELMs, new in MAST, was almost doubled using n = 2 resonant magnetic perturbations from a set of four external coils (n = 1, 2). A new internal 12 coil set (n <= 3) has been commissioned. The filaments in the inter-ELM and L-mode phase are different from ELM filaments, and the characteristics in L-mode agree well with turbulence calculations. A variety of fast particle driven instabilities were studied from 10 kHz saturated fishbone like activity up to 3.8 MHz compressional Alfven eigenmodes. Fast particle instabilities also affect the off-axis NBI current drive, leading to fast ion diffusion of the order of 0.5 m(2) s(-1) and a reduction in the driven current fraction from 40% to 30%. EBW current drive start-up is demonstrated for the first time in a ST generating plasma currents up to 55 kA. Many of these studies contributed to the physics basis of a planned upgrade to MAST.
15.	Pasqualato, G., et al. (författare) Shape evolution in even-mass 98-104Zr isotopes via lifetime measurements using the Î³ Î³-coincidence technique 2023 Ingår i: European Physical Journal A. - : Springer. - 1434-6001 .- 1434-601X. ; 59:11 Tidskriftsartikel (refereegranskat)abstract The Zirconium (Z = 40) isotopic chain has attracted interest for more than four decades. The abrupt lowering of the energy of the first 2(+) state and the increase in the transition strength B(E2; 2(1)(+) -> 0(1)(+) ) going from Zr-98 to Zr-100 has been the first example of "quantum phase transition" in nuclear shapes, which has few equivalents in the nuclear chart. Although a multitude of experiments have been performed to measure nuclear properties related to nuclear shapes and collectivity in the region, none of the measured lifetimes were obtained using the Recoil Distance Doppler Shift method in the gamma gamma-coincidence mode where a gate on the direct feeding transition of the state of interest allows a strict control of systematical errors. This work reports the results of lifetime measurements for the first yrast excited states in Zr98-104 carried out to extract reduced transition probabilities. The new lifetime values in gamma gamma-coincidence and gamma-single mode are compared with the results of former experiments. Recent predictions of the Interacting Boson Model with Configuration Mixing, the Symmetry Conserving Configuration Mixing model based on the Hartree-Fock- Bogoliubov approach and the Monte Carlo Shell Model are presented and compared with the experimental data.
16.	Polettini, M., et al. (författare) Decay studies in the A∼225 Po-Fr region from the DESPEC campaign at GSI in 2021 2022 Ingår i: Il Nuovo Cimento. - : Società Italiana di Fisica. - 2037-4909. ; 45:5 Tidskriftsartikel (refereegranskat)abstract The HISPEC-DESPEC collaboration aims at investigating the structure of exotic nuclei formed in fragmentation reactions with decay spectroscopy measurements, as part of the FAIR Phase-0 campaign at GSI. This paper reports on first results of an experiment performed in spring 2021, with a focus on beta-decaystudies in the Po-Fr nuclei in the 220 < A <230 island of octupole deformation exploiting the DESPEC setup. Ion-beta correlations and fast-timing techniques are being employed, giving an insight into this difficult-to-reach region.
17.	Ciemala, M., et al. (författare) Testing ab initio nuclear structure in neutron-rich nuclei : Lifetime measurements of second 2(+) state in C-16 and O-20 2020 Ingår i: Physical Review C. - : AMER PHYSICAL SOC. - 2469-9985 .- 2469-9993. ; 101:2 Tidskriftsartikel (refereegranskat)abstract To test the predictive power of ab initio nuclear structure theory, the lifetime of the second 2(+) state in neutron-rich O-20, tau(2(2)(+)) = 150(-30)(+80) fs, and an estimate for the lifetime of the second 2(+) state in C-16 have been obtained for the first time. The results were achieved via a novel Monte Carlo technique that allowed us to measure nuclear state lifetimes in the tens-to-hundreds of femtoseconds range by analyzing the Doppler-shifted gamma-transition line shapes of products of low-energy transfer and deep-inelastic processes in the reaction O-18 (7.0 MeV/u) + Ta-181. The requested sensitivity could only be reached owing to the excellent performances of the Advanced gamma-Tracking Array AGATA, coupled to the PARIS scintillator array and to the VAMOS++ magnetic spectrometer. The experimental lifetimes agree with predictions of ab initio calculations using two- and three-nucleon interactions, obtained with the valence-space in-medium similarity renormalization group for O-20 and with the no-core shell model for C-16. The present measurement shows the power of electromagnetic observables, determined with high-precision gamma spectroscopy, to assess the quality of first-principles nuclear structure calculations, complementing common benchmarks based on nuclear energies. The proposed experimental approach will be essential for short lifetime measurements in unexplored regions of the nuclear chart, including r-process nuclei, when intense beams, produced by Isotope Separation On-Line (ISOL) techniques, become available.
18.	Girard-Alcindor, V., et al. (författare) New narrow resonances observed in the unbound nucleus F 15 2022 Ingår i: Physical Review C. - : American Physical Society (APS). - 2469-9985 .- 2469-9993. ; 105:5 Tidskriftsartikel (refereegranskat)abstract The structure of the unbound F15 nucleus is investigated using the inverse kinematics resonant scattering of a radioactive O14 beam impinging on a CH2 target. The analysis of H1(O14,p)O14 and H1(O14,2p)N13 reactions allowed the confirmation of the previously observed narrow 1/2- resonance, near the two-proton decay threshold, and the identification of two new narrow 5/2- and 3/2- resonances. The newly observed levels decay by 1p emission to the ground of O14, and by sequential 2p emission to the ground state of N13 via the 1- resonance of O14. Gamow shell model (GSM) analysis of the experimental data suggests that the wave functions of the 5/2- and 3/2- resonances may be collectivized by the continuum coupling to nearby 2p- and 1p-decay channels. The observed excitation function H1(O14,p)O14 and resonance spectrum in F15 are well reproduced in the unified framework of the GSM.
19.	Grieser, M., et al. (författare) Storage ring at HIE-ISOLDE Technical design report 2012 Ingår i: The European Physical Journal Special Topics. - : Springer Science and Business Media LLC. - 1951-6355 .- 1951-6401. ; 207:1, s. 1-117 Forskningsöversikt (refereegranskat)abstract We propose to install a storage ring at an ISOL-type radioactive beam facility for the first time. Specifically, we intend to setup the heavy-ion, low-energy ring TSR at the HIE-ISOLDE facility in CERN, Geneva. Such a facility will provide a capability for experiments with stored secondary beams that is unique in the world. The envisaged physics programme is rich and varied, spanning from investigations of nuclear ground-state properties and reaction studies of astrophysical relevance, to investigations with highly-charged ions and pure isomeric beams. The TSR might also be employed for removal of isobaric contaminants from stored ion beams and for systematic studies within the neutrino beam programme. In addition to experiments performed using beams recirculating within the ring, cooled beams can also be extracted and exploited by external spectrometers for high-precision measurements. The existing TSR, which is presently in operation at the Max-Planck Institute for Nuclear Physics in Heidelberg, is well-suited and can be employed for this purpose. The physics cases as well as technical details of the existing ring facility and of the beam and infrastructure requirements at HIE-ISOLDE are discussed in the present technical design report.
20.	Lalkovski, S., et al. (författare) Core-coupled states and split proton-neutron quasiparticle multiplets in Ag122-126 2013 Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 87:3, s. 034308- Tidskriftsartikel (refereegranskat)abstract Neutron-rich silver isotopes were populated in the fragmentation of a Xe-136 beam and the relativistic fission of U-238. The fragments were mass analyzed with the GSI Fragment Separator and subsequently implanted into a passive stopper. Isomeric transitions were detected by 105 high-purity germanium detectors. Eight isomeric states were observed in Ag122-126 nuclei. The level schemes of Ag-122,Ag-123,Ag-125 were revised and extended with isomeric transitions being observed for the first time. The excited states in the odd-mass silver isotopes are interpreted as core-coupled states. The isomeric states in the even-mass silver isotopes are discussed in the framework of the proton-neutron split multiplets. The results of shell-model calculations, performed for the most neutron-rich silver nuclei are compared to the experimental data.
21.	Boso, A., et al. (författare) Isospin dependence of electromagnetic transition strengths among an isobaric triplet 2019 Ingår i: Physics Letters B. - : ELSEVIER. - 0370-2693 .- 1873-2445. ; 797 Tidskriftsartikel (refereegranskat)abstract Electric quadrupole matrix elements, M-p, for the J(pi) = 2(+) -> 0(+), Delta T = 0, T = 1 transitions across the A = 46 isobaric multiplet Cr-46-V-46-Ti-46 have been measured at GSI with the FRS-LYCCA-AGATA setup. This allows direct insight into the isospin purity of the states of interest by testing the linearity of M-p with respect to T-z. Pairs of nuclei in the T = 1 triplet were studied using identical reaction mechanisms in order to control systematic errors. The M-p values were obtained with two different methodologies: (i) a relativistic Coulomb excitation experiment was performed for Cr-46 and Ti-46; (ii) a "stretched target" technique was adopted here, for the first time, for lifetime measurements in V-46 and Ti-46. A constant value of M-p across the triplet has been observed. Shell-model calculations performed within the fp shell fail to reproduce this unexpected trend, pointing towards the need of a wider valence space. This result is confirmed by the good agreement with experimental data achieved with an interaction which allows excitations from the underlying sd shell. A test of the linearity rule for all published data on complete T = 1 isospin triplets is presented. (C) 2019 The Author(s). Published by Elsevier B.V.
22.	Ceruti, S., et al. (författare) Isospin Mixing in Zr-80 : From Finite to Zero Temperature 2015 Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 115:22 Tidskriftsartikel (refereegranskat)abstract The isospin mixing was deduced in the compound nucleus Zr-80 at an excitation energy of E* = 54 MeV from the gamma decay of the giant dipole resonance. The reaction Ca-40 + Ca-40 at E-beam = 136 MeV was used to form the compound nucleus in the isospin I = 0 channel, while the reaction Cl-37 + Ca-44 at E-beam = 95 MeV was used as the reference reaction. The. rays were detected with the AGATA demonstrator array coupled with LaBr3:Ce detectors. The temperature dependence of the isospin mixing was obtained and the zero-temperature value deduced. The isospin-symmetry-breaking correction delta(C) used for the Fermi superallowed transitions was extracted and found to be consistent with beta-decay data.
23.	Clement, E., et al. (författare) Conceptual design of the AGATA 1 π array at GANIL 2017 Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 855, s. 1-12 Tidskriftsartikel (refereegranskat)abstract The Advanced GAmma Tracking Array (AGATA) has been installed at the GANIL facility, Caen-France. This setup exploits the stable and radioactive heavy-ions beams delivered by the cyclotron accelerator complex of GANIL. Additionally, it benefits from a large palette of ancillary detectors and spectrometers to address in-beam γ-ray spectroscopy of exotic nuclei. The set-up has been designed to couple AGATA with a magnetic spectrometer, charged-particle and neutron detectors, scintillators for the detection of high-energy γ rays and other devices such as a plunger to measure nuclear lifetimes. In this paper, the design and the mechanical characteristics of the set-up are described. Based on simulations, expected performances of the AGATA l π array are presented.
24.	Crespi, F. C. L., et al. (författare) Response of AGATA segmented HPGe detectors to gamma rays up to \SI15.1\MeV 2013 Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 705, s. 47-54 Tidskriftsartikel (refereegranskat)
25.	Gorska, M., et al. (författare) Evolution of the N=82 Shell Gap below 132Sn Inferred from Core Excited States in 131In 2009 Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 672:4-5, s. 313-316 Tidskriftsartikel (refereegranskat)abstract The gamma-ray decay of ail excited state in In-131, the one proton hole neighbor of the doubly magic (132)sn has been measured. A high-spin, core-excited isomer with T-1/2 = 630(60) us was identified following production by both relativistic fragmentation of a Xe-136 beam and fission Of a U-238 beam. This state deexcites by a single gamma-ray branch of 3782(2) keV from which direct evidence for the size of the N = 82 shell gal) is inferred. The results are discussed in comparison to a shell-model Calculation including configurations across the closed shells at N = 82 and Z = 50. (C) 2009 Elsevier B.V. All rights reserved.
26.	Hadynska-Klek, K., et al. (författare) Quadrupole collectivity in Ca-42 from low-energy Coulomb excitation with AGATA 2018 Ingår i: Physical Review C. - : AMER PHYSICAL SOC. - 2469-9985 .- 2469-9993. ; 97:2 Tidskriftsartikel (refereegranskat)abstract ACoulomb-excitation experiment to study electromagnetic properties of Ca-42 was performed using a 170-MeV calcium beam from the TANDEM XPU facility at INFN Laboratori Nazionali di Legnaro. gamma rays from excited states in Ca-42 were measured with the AGATA spectrometer. The magnitudes and relative signs of ten E2 matrix elements coupling six low-lying states in Ca-42, including the diagonal E2 matrix elements of 2(1)(+) and 2(2)(+) states, were determined using the least-squares code GOSIA. The obtained set of reduced E2 matrix elements was analyzed using the quadrupole sum rule method and yielded overall quadrupole deformation for 0(1),(+)(2) and 2(1,2)(+) states, as well as triaxiality for 0(1,2)(+) states, establishing the coexistence of a weakly deformed ground-state band and highly deformed slightly triaxial sideband in Ca-42. The experimental results were compared with the state-of-the-art large-scale shell-model and beyond-mean-field calculations, which reproduce well the general picture of shape coexistence in Ca-42.
27.	Hadynska-Klek, K., et al. (författare) Superdeformed and Triaxial States in Ca-42 2016 Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 117:6 Tidskriftsartikel (refereegranskat)abstract Shape parameters of a weakly deformed ground-state band and highly deformed slightly triaxial sideband in Ca-42 were determined from E2 matrix elements measured in the first low-energy Coulomb excitation experiment performed with AGATA. The picture of two coexisting structures is well reproduced by new state-of-the-art large-scale shell model and beyond-mean-field calculations. Experimental evidence for superdeformation of the band built on 0(2)(+) has been obtained and the role of triaxiality in the A similar to 40 mass region is discussed. Furthermore, the potential of Coulomb excitation as a tool to study superdeformation has been demonstrated for the first time.
28.	Wadsworth, R., et al. (författare) THE NORTHWEST FRONTIER : SPECTROSCOPY OF N similar to Z NUCLEI BELOW MASS 100 2009 Ingår i: Acta Physica Polonica B. - 0587-4254 .- 1509-5770. ; 40:3, s. 611-620 Tidskriftsartikel (refereegranskat)abstract The spectroscopy and structure of excited states of N similar to Z nuclei in the mass 70-100 region has been investigated using two techniques. In the A similar to 70-80 region fusion evaporation reactions coupled with the recoil-beta-tagging method have been employed at Jyvaskyla to study low-lying states in odd-odd N = Z nuclei. Results from these and other data for known odd-odd nuclei above mass 60 will be discussed. In the heavier mass 90 region a fragmentation experiment has been performed using the RIS-ING/FRS setup at GSI. This experiment was primarily aimed at searching for spin gap isomers in nuclei around A similar to 96. The objectives of the latter experiment will be discussed.
29.	Doornenbal, P., et al. (författare) RISING: Gamma‐ray Spectroscopy with Radioactive Beams at GSI 2007 Ingår i: AIP Conference Proceedings. - : AIP. - 0094-243X. - 9780735413283 ; 891, s. 99-107 Konferensbidrag (refereegranskat)abstract The Rare Isotope Spectroscopic INvestigation at GSI (RISING) project is a major pan‐European collaboration. Its physics aims are the studies of exotic nuclear matter with abnormal proton‐to‐neutron ratios compared with naturally occurring isotopes. RISING combines the FRagment Separator (FRS) which allows relativistic energies and projectile fragmentation reactions with EUROBALL Ge Cluster detectors for γ spectroscopic research. The RISING setup can be used in two different configurations. Either the nuclei of interest are investigated after being stopped or the heavy ions hit a secondary target at relativistic energies and the thereby occurring excitations are studied. For the latter case, MINIBALL Ge detectors and the HECTOR array are used in addition. Example achievements of the Fast Beam setup are presented and compared to various shell model calculations, while for the Stopped Beam setup initial results are shown.
30.	Grieser, M., et al. (författare) Storage ring at HIE-ISOLDE 2012 Ingår i: European Physical Journal: Special Topics. - : Springer Science and Business Media LLC. - 1951-6401 .- 1951-6355. ; 207:1, s. 1-117 Tidskriftsartikel (refereegranskat)abstract We propose to install a storage ring at an ISOL-type radioactive beam facility for the first time. Specifically, we intend to setup the heavy-ion, low-energy ring TSR at the HIE-ISOLDE facility in CERN, Geneva. Such a facility will provide a capability for experiments with stored secondary beams that is unique in the world. The envisaged physics programme is rich and varied, spanning from investigations of nuclear ground-state properties and reaction studies of astrophysical relevance, to investigations with highly-charged ions and pure isomeric beams. The TSR might also be employed for removal of isobaric contaminants from stored ion beams and for systematic studies within the neutrino beam programme. In addition to experiments performed using beams recirculating within the ring, cooled beams can also be extracted and exploited by external spectrometers for high-precision measurements. The existing TSR, which is presently in operation at the Max-Planck Institute for Nuclear Physics in Heidelberg, is well-suited and can be employed for this purpose. The physics cases as well as technical details of the existing ring facility and of the beam and infrastructure requirements at HIE-ISOLDE are discussed in the present technical design report.
31.	Hadynska-Klek, K., et al. (författare) Towards The Determination Of Superdeformation In Ca-42 2013 Ingår i: Acta Physica Polonica B. - 0587-4254 .- 1509-5770. ; 44:3, s. 617-625 Tidskriftsartikel (refereegranskat)abstract The Coulomb excitation experiment to study electromagnetic structure of low-lying states in Ca-42 with a focus on a possible superdeformation in this nucleus was performed at the Laboratori Nazionali di Legnaro in Italy. Preliminary values of the determined quadrupole deformation parameters for both the ground state band and the presumed superdeformed band are presented.
32.	Ilieva, S., et al. (författare) Coulomb excitation of neutron-rich Cd isotopes 2014 Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 89:1 Tidskriftsartikel (refereegranskat)abstract The isotopes (122),(124),Cd-126 were studied in a "safe" Coulomb-excitation experiment at the radioactive ion-beam facility REX-ISOLDE at CERN. The reduced transition probabilities B(E2; 0(g. s)(vertical bar) -> 2(1)(+)) and limits for the quadrupole moments of the first 2(+) excited states in the three isotopes were determined. The onset of collectivity in the vicinity of the Z = 50 and N = 82 shell closures is discussed by comparison with shell model and beyond mean-field calculations.
33.	Krzysiek, M., et al. (författare) Pygmy dipole resonance in Ce-140 via inelastic scattering of O-17 2016 Ingår i: PHYSICAL REVIEW C. - 2469-9985. ; 93:4 Tidskriftsartikel (refereegranskat)abstract The gamma decay from the high-lying states of Ce-140 excited via inelastic scattering of O-17 at a bombarding energy of 340 MeV was measured using the high-resolution AGATA-demonstrator array in coincidence with scattered ions detected in two segmented Delta E-E silicon detectors. Angular distributions of scattered ions and emitted gamma rays were measured, as well as their differential cross sections. The excitation of 1(-) states below the neutron separation energy is similar to the one obtained in reactions with the alpha isoscalar probe. The comparison between the experimental differential cross sections and the corresponding predictions using the distorted-wave Born approximation allowed us to extract the isoscalar component of identified 1(-) pygmy states. For this analysis the form factor obtained by folding microscopically calculated transition densities and optical potentials was used.
34.	Naqvi, F., et al. (författare) Isomer spectroscopy of (127)Cd 2010 Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 82:3, s. 034323- Tidskriftsartikel (refereegranskat)abstract The spin and configurational structure of excited states of (127)Cd, the two-proton and three-neutron hole neighbor of (132)Sn, has been studied. An isomeric state with a half-life of 17.5(3) mu s was populated in the fragmentation of a (136)Xe beam on a (9)Be target at a beam energy of 750 MeV/u. Time distributions of the delayed gamma transitions and gamma gamma coincidence relations were exploited to construct a decay scheme. The observed yrast (19/2)(+) isomer is proposed to have dominant configurations of nu(h(11/2)(-3))pi(g(9/2)(-1), p(1/2)(-1)), nu(h(11/2)(-2)d(3/2)(-1))pi(g(9/2)(-2)), and nu(h(11/2)(-2), s(1/2)(-1))pi(g(9/2)(-2)) and to decay by two competing stretched M2 and E3 transitions. Experimental results are compared with the isotone (129)Sn. The new information provides input for the proton-neutron interaction and the evolution of neutron hole energies in nuclei around the doubly magic (132)Sn core.
35.	Pellegri, L., et al. (författare) Pygmy dipole resonance in Sn-124 populated by inelastic scattering of O-17 2014 Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 738, s. 519-523 Tidskriftsartikel (refereegranskat)abstract The gamma decay from the high-lying states of Sn-124 was measured using the inelastic scattering of O-17 at 340 MeV. The emitted gamma rays were detected with high resolution with the AGATA demonstrator array and the scattered ions were detected in two segmented Delta E-E silicon telescopes. The angular distribution was measured both for the gamma rays and the scattered O-17 ions. An accumulation of E1 strength below the particle threshold was found and compared with previous data obtained with (gamma,gamma') and (alpha,alpha'gamma) reactions. The present results of elastic scattering, and excitation of E2 and E1 states were analysed using the DWBA approach. From this comprehensive description the isoscalar component of the 1-excited states was extracted. The obtained values are based on the comparison of the data with DWBA calculations including a form factor deduced using a microscopic transition density.
36.	Söderström, Pär-Anders, et al. (författare) High-spin structure in K-40 2012 Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 86:5, s. 054320- Tidskriftsartikel (refereegranskat)abstract High-spin states of K-40 have been populated in the fusion-evaporation reaction C-12(Si-30,np)K-40 and studied by means of gamma-ray spectroscopy techniques using one triple-cluster detector of the Advanced Gamma Tracking Array at the Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro. Several states with excitation energy up to 8 MeV and spin up to 10(-) have been discovered. These states are discussed in terms of J = 3 and T = 0 neutron-proton hole pairs. Shell-model calculations in a large model space have shown good agreement with the experimental data for most of the energy levels. The evolution of the structure of this nucleus is here studied as a function of excitation energy and angular momentum.
37.	Wadsworth, R., et al. (författare) Spin-gap Isomer in 96Cd 2012 Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6596 .- 1742-6588. ; 381:1 Tidskriftsartikel (refereegranskat)abstract Evidence has been obtained for the existence of the long predicted 16+ spin-gap isomer in 96Cd. The decay of the isomer was identified and studied following the use of an 850 MeV/u beam of 124Xe impinging on a Be target and the fragment recoil separator at the GSI Laboratory. Gamma decays from the fragments were detected using the RISING gamma ray array, in its stopped beam configuration, plus a silicon active stopper. The data obtained have been compared with shell model predictions, which indicate that the isoscalar neutron-proton interaction plays a key role in the formation of the isomer.
38.	Zanon, I., et al. (författare) High-Precision Spectroscopy of 20O Benchmarking Ab Initio Calculations in Light Nuclei 2023 Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 131:26 Tidskriftsartikel (refereegranskat)abstract The excited states of unstable 20O were investigated via γ-ray spectroscopy following the 19O(d,p)20O reaction at 8 AMeV. By exploiting the Doppler shift attenuation method, the lifetimes of the 2+2 and 3+1 states were firmly established. From the γ-ray branching and E2/M1 mixing ratios for transitions deexciting the 2+2 and 3+1 states, the B(E2) and B(M1) were determined. Various chiral effective field theory Hamiltonians, describing the nuclear properties beyond ground states, along with a standard USDB interaction, were compared with the experimentally obtained data. Such a comparison for a large set of γ-ray transition probabilities with the valence space in medium similarity renormalization group ab initio calculations was performed for the first time in a nucleus far from stability. It was shown that the ab initio approaches using chiral effective field theory forces are challenged by detailed high-precision spectroscopic properties of nuclei. The reduced transition probabilities were found to be a very constraining test of the performance of the ab initio models.
39.	Avigo, R., et al. (författare) Low-lying electric dipole gamma-continuum for the unstable Fe-62,64 nuclei : Strength evolution with neutron number 2020 Ingår i: Physics Letters B. - : ELSEVIER. - 0370-2693 .- 1873-2445. ; 811 Tidskriftsartikel (refereegranskat)abstract The gamma-ray emission from the nuclei Fe-62,Fe-64 following Coulomb excitation at bombarding energy of 400-440 AMeV was measured with special focus on E1 transitions in the energy region 4-8 MeV. The unstable neutron-rich nuclei Fe-62,Fe-64 were produced at the FAIR-GSI laboratories and selected with the FRS spectrometer. The gamma decay was detected with AGATA. From the measured gamma-ray spectra the summed E1 strength is extracted and compared to microscopic quasi-particle phonon model calculations. The trend of the E1 strength with increasing neutron number is found to be fairly well reproduced with calculations that assume a rather complex structure of the 1(-) states (three-phonon states) inducing a strong fragmentation of the E1 nuclear response below the neutron binding energy.
40.	Birkenbach, B., et al. (författare) Spectroscopy of the neutron-rich actinide nucleus U-240 following multinucleon-transfer reactions 2015 Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 92:4 Tidskriftsartikel (refereegranskat)abstract Background: Nuclear structure information for the neutron-rich actinide nuclei is important since it is the benchmark for theoretical models that provide predictions for the heaviest nuclei. Purpose: gamma-ray spectroscopy of neutron-rich heavy nuclei in the actinide region. Method: Multinucleon-transfer reactions in Zn-70 + U-238 and Xe-136 + U-238 have been measured in two experiments performed at the INFN Legnaro, Italy. In the Zn-70 experiment the high-resolution HPGe Clover Array (CLARA) coupled to the magnetic spectrometer PRISMA was employed. In the Xe-136 experiment the high-resolution Advanced Gamma Tracking Array (AGATA) was used in combination with PRISMA and the Detector Array for Multinucleon Transfer Ejectiles (DANTE). Results: The ground-state band (g.s. band) of U-240 was measured up to the 20(+) level and a tentative assignment was made up to the (24(+)) level. Results from gamma gamma coincidence and from particle coincidence analyses are shown. Moments of inertia (MoI) show a clear upbend. Evidence for an extended first negative-parity band of U-240 is found. Conclusions: A detailed comparison with latest calculations shows best agreement with cranked relativistic Hartree-Bogoliubov (CRHB) calculations for the g.s. band properties. The negative-parity band shows the characteristics of a K-pi = 0 band based on an octupole vibration.
41.	Boutachkov, P., et al. (författare) High-spin isomers in 96Ag : excitations across the Z=38 and Z=50, N=50 closed shells 2011 Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 84:4 Tidskriftsartikel (refereegranskat)abstract Excited states in (96)Ag were populated in fragmentation of an 850-MeV/u (124)Xe beam on a 4-g/cm(2) Be target. Three new high-spin isomers were identified and the structure of the populated states was investigated. The level scheme of (96)Ag was established, and a spin parity of (13(-)), (15(+)), and (19(+)) was assigned to the new isomeric states. Shell-model calculations were performed in various model spaces, including pi nu(p(1/2), g(9/2), f(5/2), p(3/2)) and the large-scale shell-model space pi nu(gds), to account for the observed parity changing M2 and E3 transitions from the (13(-)) isomer and the E2 and E4 transitions from the (19(+)) core-excited isomer, respectively. The calculated level schemes and reduced transition strengths are found to be in very good agreement with the experiment.
42.	Brock, T. S., et al. (författare) Observation of a new high-spin isomer in $^{94}\mathrm{Pd}$ 2010 Ingår i: Physical Review C. ; 82:6 Tidskriftsartikel (refereegranskat)
43.	Brock, T. S., et al. (författare) Observation of a new high-spin isomer in Pd-94 2010 Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 82:6, s. 061309- Tidskriftsartikel (refereegranskat)abstract A second gamma-decaying high-spin isomeric state, with a half-life of 197(22) ns, has been identified in the N = Z + 2 nuclide Pd-94 as part of a stopped-beam Rare Isotope Spectroscopic INvestigation at GSI (RISING) experiment. Weisskopf estimates were used to establish a tentative spin/parity of 19(-), corresponding to the maximum possible spin of a negative parity state in the restricted (p(1/2), g(9/2)) model space of empirical shell model calculations. The reproduction of the E3 decay properties of the isomer required an extension of the model space to include the f (5/2) and p(3/2) orbitals using the CD-Bonn potential. This is the first time that such an extension has been required for a high-spin isomer in the vicinity of Sn-100 and reveals the importance of such orbits for understanding the decay properties of high-spin isomers in this region. However, despite the need for the extended model space for the E3 decay, the dominant configuration for the 19(-) state remains (p p(1/2)(-1)g(9/2)(-3))(11)circle times(nu g(9/2)(-2))(8). The half-life of the known, 14(+), isomer was remeasured and yielded a value of 499(13) ns.
44.	Crespi, F. C. L., et al. (författare) 1(-) and 2(+) discrete states in Zr-90 populated via the (O-17, O-17 'gamma) reaction 2015 Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 91:2 Tidskriftsartikel (refereegranskat)abstract 2(+) and 1(-) states in Zr-90 were populated via the (O-17, O-17 'gamma) reaction at 340 MeV. The gamma decay was measured with high resolution using the AGATA (advanced gamma tracking array demonstrator array). Differential cross sections were obtained at few different angles for the scattered particle. The results of the elastic scattering and inelastic excitation of 2(+), 3(,)(-) and 1(-) states are compared with distorted-wave Born approximation (DWBA) calculations, using both the standard collective form factor and a form factor obtained by folding microscopically calculated transition densities. This allowed to extract the isoscalar component of the 1(-) state at 6.424 MeV. The comparison of the present (17O, 17O 'gamma) data with existing (gamma,gamma') and (p, p') data in the corresponding region of the gamma continuum (6-11 MeV), characterized by a large E1 component, shows completely different behaviors of the cross section as a function of the nuclear excitation energy. The comparison of the data with DWBA calculations suggests a decrease of the isoscalar strength in the cross section with increasing excitation energy.
45.	Crespi, F. C. L., et al. (författare) Isospin Character of Low-Lying Pygmy Dipole States in Pb-208 via Inelastic Scattering of O-17 Ions 2014 Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 113:1, s. 012501- Tidskriftsartikel (refereegranskat)abstract The properties of pygmy dipole states in Pb-208 were investigated using the Pb-208(O-17, O-17'gamma) reaction at 340 MeV and measuring the gamma decay with high resolution with the AGATA demonstrator array. Cross sections and angular distributions of the emitted gamma rays and of the scattered particles were measured. The results are compared with (gamma, gamma') and (p, p') data. The data analysis with the distorted wave Born approximation approach gives a good description of the elastic scattering and of the inelastic excitation of the 2(+) and 3(-) states. For the dipole transitions a form factor obtained by folding a microscopically calculated transition density was used for the first time. This has allowed us to extract the isoscalar component of the 1(-) excited states from 4 to 8 MeV.
46.	Guastalla, G., et al. (författare) Analysis and Results of the 104Sn Coulomb Excitation Experiment 2014 Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6596 .- 1742-6588. ; 533:1 Konferensbidrag (refereegranskat)abstract The analysis of the Coulomb excitation experiment conducted on 104Sn required a strict selection of the data in order to reduce the large background present in the gamma-ray energy spectra and identify the gamma-ray peak corresponding to the Coulomb excitation events. As a result the B(E2; 0 + -> 2+) value could be extracted, which established the downward trend towards 100Sn and therefore the robustness of the N=Z=50 core against quadrupole excitations.
47.	John, P. R., et al. (författare) In-beam gamma-ray spectroscopy of the neutron-rich platinum isotope Pt-200 toward the N=126 shell gap 2017 Ingår i: Physical Review C. - : AMER PHYSICAL SOC. - 2469-9985 .- 2469-9993. ; 95:6 Tidskriftsartikel (refereegranskat)abstract The neutron-rich nucleus Pt-200 is investigated via in-beam gamma-ray spectroscopy to study the shape evolution in the neutron-rich platinum isotopes towards the N = 126 shell closure. The two-neutron transfer reaction Pt-198(Se-82, Se-80)Pt-200 is used to populate excited states of Pt-200. The Advanced Gamma Ray Tracking Array (AGATA) demonstrator coupled with the PRISMA spectrometer detects gamma rays coincident with the Se-80 recoils, the binary partner of Pt-200. The binary partner method is applied to extract the gamma-ray transitions and build the level scheme of Pt-200. The level at 1884 keV reported by Yates et al. [S. W. Yates, E. M. Baum, E. A. Henry, L. G. Mann, N. Roy, A. Aprahamian, R. A. Meyer, and R. Estep, Phys. Rev. C 37, 1889 (1988)] was confirmed to be at 1882.1 keV and assigned as the (6(1)(+)) state. An additional gamma ray was found and it presumably deexcites the (8(1)(+)) state. The results are compared with state-of-the-art beyond mean-field calculations, performed for the even-even Pt190-204 isotopes, revealing that Pt-200 marks the transition from the gamma-unstable behavior of lighter Pt nuclei towards a more spherical one when approaching the N = 126 shell closure.
48.	John, P. R., et al. (författare) Shape evolution in the neutron-rich osmium isotopes : Prompt gamma-ray spectroscopy of Os-196 2014 Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 90:2, s. 021301- Tidskriftsartikel (refereegranskat)abstract The shape transition in the neutron-rich Os isotopes is studied by investigating the neutron-rich Os-196 nucleus through in-beam gamma-ray spectroscopy using a two-proton transfer reaction from a Pt-198 target to a Se-82 beam. The beam-like recoils were detected and identified with the large-acceptance magnetic spectrometer PRISMA, and the coincident gamma rays were measured with the advanced gamma tracking array (AGATA) demonstrator. The de-excitation of the low-lying levels of the yrast-band of Os-196 were identified for the first time. The results are compared with state-of-the-art beyond-mean-field calculations, performed for the even-even Os188-198 isotopes. The new results suggest a smooth transition in the Os isotopes from a more axial rotational behavior towards predominately vibrational nuclei through triaxial configurations. An almost perfect gamma-unstable/triaxial rotor yrast band is predicted for Os-196 which is in agreement with the experimentally measured excited states.
49.	Louchart, C., et al. (författare) Collective nature of low-lying excitations in Zn-70,Zn-72,Zn-74 from lifetime measurements using the AGATA spectrometer demonstrator 2013 Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 87:5 Tidskriftsartikel (refereegranskat)abstract Background: Neutron-rich nuclei with protons in the fp shell show an onset of collectivity around N=40. Spectroscopic information is required to understand the underlying mechanism and to determine the relevant terms of the nucleon-nucleon interaction that are responsible for the evolution of the shell structure in this mass region. Methods: We report on the lifetime measurement of the first 2(+) and 4(+) states in Zn-70,Zn-72 ,Zn-74 and the first 6(+) state in Zn-72 using the recoil distance Doppler shift method. The experiment was carried out at the INFN Laboratory of Legnaro with the AGATA demonstrator, first phase of the Advanced Gamma Tracking Array of highly segmented, high-purity germanium detectors coupled to the PRISMA magnetic spectrometer. The excited states of the nuclei of interest were populated in the deep inelastic scattering of a Ge-76 beam impinging on a U-238 target. Results: The maximum of collectivity along the chain of Zn isotopes is observed for Zn-72 at N=42. An unexpectedly long lifetime of 20(-5.2)(+1.8) ps was measured for the 4(+) state in Zn-74. Conclusions: Our results lead to small values of the B(E2;4(1)(+) -> 21(+))/B(E2;2(1)(+->)0(1)(+)) ratio for Zn-72,Zn-74, suggesting a significant noncollective contribution to these excitations. These experimental results are not reproduced by state-of-the-art microscopic models and call for lifetime measurements beyond the first 2(+) state in heavy zinc and nickel isotopes.
50.	Nara Singh, B. S., et al. (författare) Exotic Nuclear Studies Around and Below A=100 2011 Ingår i: 4th International Conference on Proton Emitting Nuclei and Related Topics, PROCON2011. - : AIP. - 9780735409835 ; 1409, s. 19-24 Konferensbidrag (refereegranskat)abstract A RISING experiment with an aim to study exotic Cd nuclei was carried out at GSI-FRS facility. Some preliminary results from this experiment are presented here. In particular, the β decay of 96Cd to 96Ag revealed the existence of a high spin isomer predicted a few decades ago. In this context, the structures of both these nuclei are discussed. Shell model calculations using the Gross-Frenkel interaction are used to interpret the results.

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