Papers by Nicolae Victor Zamfir
The Tandem Van de Graaff accel-erator is one of the main experimental
The commissioning of CCR (Radiopharmaceuticals Research Centre) at IFIN-HH is reviewed. CCR is a ... more The commissioning of CCR (Radiopharmaceuticals Research Centre) at IFIN-HH is reviewed. CCR is a stateof-the-art facility based on a cyclotron and radiochemistry, dedicated to radioisotopes studies and preparation of radiopharmaceuticals for clinical use. Its unique characteristics and performance open new perspectives for significant future achievements in these multidisciplinary areas.
Recent studies show that in the transitional nucleus ^152Sm_90 a spherical excited configuration ... more Recent studies show that in the transitional nucleus ^152Sm_90 a spherical excited configuration coexists with a deformed ground state configuration. Detailed knowledge of other N=90 nuclei is important in studying the evolution of the shape/phase coexistence picture along this isotonic chain. The low-lying non-yrast states of ^156Dy_90 were populated in beta decay and studied through gamma-ray spectroscopy at the Yale
AIP Conference Proceedings, 2002
High spin states were studied in 140Eu in a search for evidence of chiral structure.
AIP Conference Proceedings, 2005
The results from two surrogate reaction experiments using the STARS (Silicon Telescope Array for ... more The results from two surrogate reaction experiments using the STARS (Silicon Telescope Array for Reaction Studies) spectrometer are presented. The surrogate method involves measuring the particle and/or γ-ray decay probabilities of excited nuclei populated via a direct reaction. These probabilities can then be used to deduce neutroninduced reaction cross sections that lead to the same compound nuclei. In the first experiment STARS coupled to the GAMMASPHERE γ-ray spectrometer successfully reproduce surrogate (n,γ), (n,n'γ) and (n,2nγ) cross sections on 155,156 Gd using 3 He-induced reactions. In the second series of experiments an energetic deuteron beam from the ESTU tandem at the Wright Nuclear Structure Lab at Yale University was used to obtain the ratio of fission probabilities for 238 U/ 236 U and 237 U/ 239 U populated using the 236,238 U(d,d'f) and 236,238 U(d,pf) reactions. Results from these experiments are presented and the implications for the surrogate reaction technique are discussed.
The European Physical Journal Special Topics, 2014
The field of the uncharted territory of high-intensity laser interaction with matter is confronte... more The field of the uncharted territory of high-intensity laser interaction with matter is confronted with new exotic phenomena and, consequently, opens new research perspectives. The intense laser beams interacting with a gas or solid target generate beams of electrons, protons and ion. These beams can induce nuclear reactions. Electrons also generate ions high-energy photons via bremsstrahlung processes which can also induce nuclear reactions. In this context a new research domain began to form in the last decade or so, namely nuclear physics with high power lasers. The observation of high brilliance proton beams of tens of MeV energy from solid targets has stimulated an intense research activity. The laser-driven particle beams have to compete with conventional nuclear accelerator-generated beams. The ultimate goal is aiming at applications of the laser produced beams in research, technology and medicine. The mechanism responsible for ion acceleration are currently subject of intensive research in many laboratories in the world. The existing results, experimental and theoretical, and their perspectives are reviewed in this article in the context of IZEST and the scientific program of ELI-NP.
AIP Conference Proceedings, 2002
The Wright Nuclear Structure Laboratory has recently acquired a gas-filled recoil separator previ... more The Wright Nuclear Structure Laboratory has recently acquired a gas-filled recoil separator previously used at Berkeley National Laboratory for heavy-element synthesis. The separator will be used to separate reaction recoils from primary beam particles and fission products following target bombardment. Commisioning of the separator has recently been completed, and the structure of 203Rn investigated.
Nuclear Structure, 2001
... IN THE LIGHT ACTINIDES AND THE SPDF-IBA MODEL NV ZAMFIR WNSL Yale University, New Haven, CT 0... more ... IN THE LIGHT ACTINIDES AND THE SPDF-IBA MODEL NV ZAMFIR WNSL Yale University, New Haven, CT 06520, USA Clark University, Worcester, MA 01610, USA ... Acknowledgments Valuable discussions with Dimitri Kusnezov and Rick Casten are gratefully acknowledged. ...
Capture Gamma-Ray Spectroscopy and Related Topics - Proceedings of the Eleventh International Symposium, 2003
The nuclear phase/shape transition in the framework of the Interacting Boson Model is analyzed in... more The nuclear phase/shape transition in the framework of the Interacting Boson Model is analyzed in detail and the predictions of this model are compared with the evolution of basic observables in the region Z=58-76, N=84-100.
This conference proceedings volume contains recent achievements in nuclear structure physics and ... more This conference proceedings volume contains recent achievements in nuclear structure physics and new developments in experiment and theory; evolution of nuclear structure; shape transitional behavior, and the associated critical point symmetries. Additionally, the conference honored the 60th birthday of Rick Casten, one of the leading contributors to this field.
Journal of Physics G: Nuclear Physics, 1981
ABSTRACT Potential energy surfaces of Kr isotopes computed in the variables ( epsilon , gamma ) a... more ABSTRACT Potential energy surfaces of Kr isotopes computed in the variables ( epsilon , gamma ) are presented. They account qualitatively for the main features observed experimentally for the lighter isotopes and predict that a shape phase transition, similar to that known for the heavy (A approximately 100) Sr and Zr nuclei, should be observed in the neutron-rich isotopes between the neutron numbers 58 and 60.
Journal of Physics G: Nuclear Physics, 1978
ABSTRACT The reaction 73Ge(16O,3n) at 52.0 MeV incident energy was used to populate excited state... more ABSTRACT The reaction 73Ge(16O,3n) at 52.0 MeV incident energy was used to populate excited states of 86Zr. Lifetimes of several of these states were determined with the aid of the recoil-distance Doppler-shift method. The resulting gamma ray transition probabilities are discussed in connection with the existing values in other Zr isotopes.
The B(E2:2^+_1arrow0^+_1) values of the neutron rich Radioactive Nuclear Beams (RNBs) ^132,134Te ... more The B(E2:2^+_1arrow0^+_1) values of the neutron rich Radioactive Nuclear Beams (RNBs) ^132,134Te were measured via Coulomb excitation in inverse kinematics at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory. This constitutes the first results from the GRAFIK detector for RNBs. The 350 MeV RNB was Coulomb excited upon a 1.0 mg/cm^2 ^12C target while the beam intensity was monitored with two microchannel plate counting foil detectors placed upstream of the GRAFIK apparatus. The through-well NaI(Tl) detector was coupled with a position sensitive microchannel plate detector(NIM A454, 409 (2000)) using a tilted Mylar foil with a center through-hole for the efficient detection of gamma-rays in coincidence with large-angle scattered beam nuclei. Results will be shown and the applicability of the method to future RNBs will be discussed. This research was supported by the US DOE under the grants DE-FG02-01ER-40609 and DE-FG-88ER-40417 and contract numbers DE-AC05...
Nuclear structure change from spherical to quadrupole deformed shape is studied in the framework ... more Nuclear structure change from spherical to quadrupole deformed shape is studied in the framework of the Interacting Boson Model (IBM). Detailed evolution of the total energy of the system in the phase/shape transition region is presented in the symmetry triangle of the IBM parameter space. It is shown how the coexistence region in the U(5)-SU(3) first order phase transition evolves to a single point of the U(5)-O(6) second order phase transition. This change, from the axially symmetric to the gamma soft transition, is illustrated through the behavior of different basic low-energy observables. Based on experimental data, trajectories of different isotopic chains in the symmetry triangle are established. Supported by US-DOE Grants Nos. DE-FG02-91ER-40609 and DE-FG02-88ER-40417.
Physics of Atomic Nuclei, 2001
Physical Review Letters, 2004
Quantum phase transitions in mesoscopic systems are studied. It is shown that the main features o... more Quantum phase transitions in mesoscopic systems are studied. It is shown that the main features of phase transitions, defined for infinite number of particles, N ! 1, persist even for moderate N 10: A Landau analysis of first order transitions is done and a ''critical'' exponent at the spinodal point is defined. Two order parameters are introduced to distinguish first from second order transitions. Applications to atomic nuclei, molecules, atomic clusters, and finite polymers are mentioned. Experimental evidence in atomic nuclei is presented.
Physical Review C, 2004
The discovery of a set of analytic solutions to describe nuclei at the critical point of spherica... more The discovery of a set of analytic solutions to describe nuclei at the critical point of spherical-deformed phase transitions has led to an increased interest in the properties of 0 + excited states. This idea provides the motivation for the present investigation to determine sets of interacting boson model (IBA) parameters that reproduce the properties of all low-lying, positive-parity excitations, including the first excited 0 + state, for a wide range of even-even, collective nuclei. Detailed fits of isotopic chains in the rare-earth region are shown to reproduce the energies of the positive-parity states and to provide a reasonable description of their transition matrix elements. Two neutron separation energies, isomer shifts, and isotope shifts are also described using a truncated IBA-1 Hamiltonian. A proposed set of polar coordinates allows for a mapping of these parameters into the IBA symmetry triangle and a comparison of trajectories for different isotopic chains.
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Papers by Nicolae Victor Zamfir