Author
J. Nyberg
Bio: J. Nyberg is an academic researcher from Niels Bohr Institute. The author has contributed to research in topics: Neutron & Spin states. The author has an hindex of 11, co-authored 32 publications receiving 519 citations.
Topics: Neutron, Spin states, Nuclear reaction, Proton, Yrast
Papers
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TL;DR: In this paper, two-quasiparticle bands of positive parity (S-bands) in even-even nuclei in the Xe-Ba-Ce region are systematically examined.
103 citations
15 Jan 1991-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this paper, a 2π neutron and γ-ray multiplicity filter designed as a part of the NORDBALL detection system is described, which consists of ten hexagon and six pentagon shaped detectors filled with BC501 liquid scintillator.
Abstract: A description of the 2π neutron and γ-ray multiplicity filter designed as a part of the NORDBALL detection system is given. The filter consists of ten hexagon and six pentagon shaped detectors filled with BC501 liquid scintillator. Individual detector properties as well as system behaviour including neutron scattering are discussed and test results are presented. The properties of the n-γ pulse shape discriminators used for the system were studied. The discriminators, based on the zero-crossing principle, showed a very efficient separation in the 100:1 dynamic range of neutrons and γ-rays starting from 70 keV of recoil electron energy. Results from a use of the filter in a study of the 28 Si + 58 Ni reaction are presented.
59 citations
TL;DR: In this paper, the angular distributions of photons associated with the damping of excited-state giant dipole resonances (GDR) in hot and rotating 161,162 Yb nuclei have been measured in exclusive experiments using the HECTOR array.
58 citations
TL;DR: In this article, high-spin states have been observed in the odd-odd isotope 120C in 32S-induced reactions and the previously known band was extended to higher spin and several new bands were identified.
35 citations
TL;DR: In this paper, the lifetime limits of 20 yrast levels in 110 Cd have been measured using the recoil distance method and the NORDBALL array of Compton-suppressed Ge detectors.
29 citations
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TL;DR: In this article, two main theoretical approaches for shape coexistence in doubly even nuclei are presented, the shell model and the deformed mean field approach, which is broadly defined so that it includes various truncation schemes, including generalized seniority and the interacting boson model.
400 citations
TL;DR: In this article, the concept of spontaneous symmetry breaking is applied to the rotating mean field of nuclei, which is based on the tilted-axis cranking model, taking into account that the rotational axis can take any orientation with respect to the deformed density distribution.
Abstract: The concept of spontaneous symmetry breaking is applied to the rotating mean field of nuclei. The description is based on the tilted-axis cranking model, which takes into account that the rotational axis can take any orientation with respect to the deformed density distribution. The appearance of rotational bands in nuclei is analyzed, focusing on weakly deformed nuclei at high angular momentum. The quantization of the angular momentum of the valence nucleons leads to new phenomena. Magnetic rotation represents the quantized rotation of the anisotropic current distribution in a near spherical nucleus. The restricted amount of angular momentum of the valence particles causes band termination. The discrete symmetries of the mean-field Hamiltonian provide a classification scheme of rotational bands. New symmetries result from the combination of the spatial symmetries of the density distribution with the vector of the angular momentum. The author discusses in detail which symmetries appear for a reflection-symmetric density distribution and how they show up in the properties of the rotational bands. In particular, the consequences of rotation about a nonprincipal axis and of breaking the chiral symmetry are analyzed. Also discussed are which symmetries and band structures appear for non-reflection-symmetric mean fields. The consequences of breaking the symmetry with respect to gauge and isospin rotations are sketched. Some analogies outside nuclear physics are mentioned. The application of symmetry-restoring methods to states with large angular momentum is reviewed.
396 citations
TL;DR: In this paper, the authors apply the tilted axis turning theory to the model of two particles coupled to a triaxial rotor and compare the interpretation and quality of the mean field approximation.
333 citations
TL;DR: In this article, the decay of 132La to 132Ba has been studied in several works, including some recent papers, but in the opinion of the evaluators, this decay scheme still suffers from incompleteness, especially from the point of view of separate level schemes from the ground state and the isomeric activities.
176 citations
University of Cologne1, CERN2, University of Groningen3, Ludwig Maximilian University of Munich4, Technische Universität Darmstadt5, Technische Universität München6, University of Liverpool7, Lund University8, University of Edinburgh9, Petersburg Nuclear Physics Institute10, University of Paris-Sud11, Helsinki Institute of Physics12, University of Jyväskylä13, University of Warsaw14, University of York15, University of Göttingen16, University of Bonn17, University of Maryland, College Park18
TL;DR: The Miniball germanium detector array has been operational at the REX (Radioactive ion beam EXperiment) post accelerator at the Isotope Separator On-Line facility ISOLDE at CERN since 2001.
Abstract: The Miniball germanium detector array has been operational at the REX (Radioactive ion beam EXperiment) post accelerator at the Isotope Separator On-Line facility ISOLDE at CERN since 2001. During the last decade, a series of successful Coulomb excitation and transfer reaction studies have been performed with this array, utilizing the unique and high-quality radioactive ion beams which are available at ISOLDE. In this article, an overview is given of the technical details of the full Miniball setup, including a description of the \(\gamma\)-ray and particle detectors, beam monitoring devices and methods to deal with beam contamination. The specific timing properties of the REX-ISOLDE facility are highlighted to indicate the sensitivity that can be achieved with the full Miniball setup. The article is finalized with a summary of some physics highlights at REX-ISOLDE and the utilization of the Miniball germanium detectors at other facilities.
128 citations