Search results for "Neutron number"
showing 10 items of 46 documents
Low-lying electric dipole gamma-continuum for the unstable Fe-62,64 nuclei : Strength evolution with neutron number
2020
6 pags., 4 figs.
Evidence of a sudden increase in the nuclear size of proton-rich silver-96
2021
Understanding the evolution of the nuclear charge radius is one of the long-standing challenges for nuclear theory. Recently, density functional theory calculations utilizing Fayans functionals have successfully reproduced the charge radii of a variety of exotic isotopes. However, difficulties in the isotope production have hindered testing these models in the immediate region of the nuclear chart below the heaviest self-conjugate doubly-magic nucleus 100Sn, where the near-equal number of protons (Z) and neutrons (N) lead to enhanced neutron-proton pairing. Here, we present an optical excursion into this region by crossing the N = 50 magic neutron number in the silver isotopic chain with th…
Spectroscopy of the Heaviest Elements
2011
The addition of modern arrays of silicon and germanium detectors at the target and focal plane positions of recoil separators has led to a wealth of new spectroscopic data concerning the structure of heavy elements. A particular region of interest has been that of the deformed nuclei close to the N=152 subshell gap. Both detailed decay and in-beam spectroscopic studies have provided complementary data on the location and ordering of single-particle states for proton number in the region of Z=100 and neutron number N=152. Instrumentation developments have allowed in-beam studies to be carried out at the unprecedented level of 20 nanobarns. The future prospects for such studies are also brigh…
Measurement and microscopic description of odd-even staggering of charge radii of exotic copper isotopes
2020
Isotopes with an odd number of neutrons are usually slightly smaller in size than their even-neutron neighbours. In charge radii of short-lived copper isotopes, a reduction of this effect is observed when the neutron number approaches fifty. The mesoscopic nature of the atomic nucleus gives rise to a wide array of macroscopic and microscopic phenomena. The size of the nucleus is a window into this duality: while the charge radii globally scale as $A^{1/3}$, their evolution across isotopic chains reveals unanticipated structural phenomena [1-3]. The most ubiquitous of these is perhaps the Odd-Even Staggering (OES) [4]: isotopes with an odd number of neutrons are usually smaller in size than …
Optical spectroscopy using mass-separated beams: Nuclear properties of unstable indium and tin isotopes
1987
Abstract Collinear fast-beam laser-spectroscopy has been used to measure the hyperfine structure and isotope shift of several indium and tin isotopes. The related experimental techniques are described, including the preparation of mass-separated beams of neutron-deficient indium and tin isotopes at the GSI on-line mass separator following fusion-evaporation reactions. The deviation of the observed dependence of the charge radii upon the neutron number from the expected behaviour is briefly discussed.
Structure of transactinide nuclei with relativistic energy density functionals
2013
A microscopic theoretical framework based on relativistic energy density functionals (REDFs) is applied to studies of shape evolution, excitation spectra, and decay properties of transactinide nuclei. Axially symmetric and triaxial relativistic Hartree-Bogoliubov (RHB) calculations, based on the functional DD-PC1 and with a separable pairing interaction, are performed for the even-even isotopic chains between Fm and Fl. The occurrence of a deformed shell gap at neutron number $N=162$ and its role on the stability of nuclei in the region around $Z=108$ is investigated. A quadrupole collective Hamiltonian, with parameters determined by self-consistent constrained triaxial RHB calculations, is…
About the Reliability of Extrapolation of Nuclear Structure Data for r-process Calculations
2002
Gross decay properties are the nuclear part of the input for calculations of elemental abundances. They depend, sometimes very sensitively, on details of nuclear structure. Models for predictions of nuclear masses and shapes have to be used for isotopes very far from stability. The reliability of extrapolations far from experimentally reachable nuclei is, however, not always granted due to singularities in the nuclear landscape. We review data on the region of the neutron-rich isotopes near A = 100, which is a region of especially dramatic changes.
Proton-Rich Light Nuclei
1989
A basic question for a given element of how few or how many neutrons can be contained in its nucleus and still result in a “bound” system, and the resulting consequences on our present concept of nuclear structure, have been the focus of much recent research on highly unstable nuclei. It is only during the last several years that the limit of nuclear stability has been reached in a few areas of the nuclear chart. Except among the lightest elements, knowledge of the limit on the neutron-excess side is still beyond our experimental capability. For the heavier elements, the gap between the most neutron-rich isotope known and the isotope which is predicted to define the neutron drip-line more o…
Search for Superheavy Elements — A Status Report
1986
A survey is given of nuclear and chemical properties in the predicted island of spherical superheavy nuclei around element 114 and of recent attempts to produce such nuclei by transfer and fusion reactions.
Properties of heavy nuclei measured at the GSI SHIP
2004
Abstract The nuclear shell model predicts that the next doubly magic shell-closure beyond 208 Pb is at a proton number Z = 114, 120, or 126 and at a neutron number N = 172 or 184. The outstanding aim of experimental investigations is the exploration of this region of spherical ‘Super-Heavy Elements’ (SHEs). The measured decay data reveal that for the heaviest elements, the dominant decay mode is α emission, not fission. Decay properties as well as reaction cross-sections are compared with results of theoretical investigations. Finally, plans are presented for the further development of the experimental set-up and the application of new techniques.At a higher sensitivity, the exploration of …