Search results for "nuclear structure"
showing 10 items of 401 documents
Coulomb shifts and shape changes in the mass 70 region
2007
The technique of recoil beta tagging has been developed which allows prompt gamma decays in nuclei from excited states to be correlated with electrons from their subsequent short-lived beta decay. This technique is ideal for studying nuclei very far from stability and improves in sensitivity for very short-lived decays and for high decay Q-values. The method has allowed excited states in 78Y to be observed for the first time, as well as an extension in the knowledge of T=1 states in 74Rb. From this new information it has been possible to compare Coulomb energy differences (CED) between T=1 states in 70Br/70Se, 74Rb/74Kr, and 78Y/78Sr. The A=70 CED exhibit an anomalous behavior which is inco…
Beta decay of $^{56}$Cu
2001
AbstractThe proton-rich isotope 56 Cu was produced at the GSI On-Line Mass Separator by means ofthe 28 Si( 32 S, p3n) fusion–evaporation reaction. Its β -decay properties were studied by detecting β -delayed γ rays and protons. A half-life of 93± 3 ms was determined for 56 Cu. Compared to theprevious work, six new γ rays and three new levels were assigned to the daughter nucleus 56 Ni. Themeasured Gamow–Teller strength values for five 56 Ni levels are compared toshell-model predictions. 2001 Elsevier Science B.V. All rights reserved. PACS: 21.10.-k; 23.40.-s; 21.60.Cs; 27.40.+zKeywords: R ADIOACTIVITY 56 Cu ( β + ) [from 28 Si( 32 S, p3n)]; Measured E γ , I ; Deduced β -intensity and β -st…
New lifetime measurements inPd109and the onset of deformation atN=60
2015
Several new subnanosecond lifetimes were measured in Pd-109 using the fast-timing beta gamma gamma (t) method. Fission fragments of the A = 109 mass chain were produced by bombarding natural uranium with 30 MeV protons at the Jyvaskyla Ion Guide Isotope Separator On-Line (IGISOL) facility. Lifetimes were obtained for excited states in Pd-109 populated following beta decay of Rh-109. The new lifetimes provide some insight into the evolution of nuclear structure in this mass region. In particular, the distinct structure of the two low-lying 7/2(+) states occurring systematically across the Pd isotopic chain is supported by the new lifetime measurements. The available nuclear data indicate a s…
Investigations into the alpha-decay of 195At
2003
The low-energy nuclear structure and decay properties of the neutron-deficient isotopes 195At and 191Bi have been studied. 195At was produced in the reaction 142Nd(56Fe,p2n)195At and 191Bi as the daughter activity of 195At. The activities were implanted in a position-sensitive silicon detector after being separated from the primary beam by a gas-filled recoil separator. The 1/2+ intruder state was determined to be the ground state in 195At with an alpha-decay energy of E α = 6953(3) keV and a half-life T 1/2 = 328(20) ms. Another state with an alpha-decay energy E α = 7075(4) keV and a half-life T 1/2 = 147(5) ms was found to decay to a 148.7(5) keV excited state in 191Bi for which a spin a…
Laser spectroscopy for nuclear structure physics
2016
High-resolution laser spectroscopy is an established powerful tool in the study of nuclear shape, size and multipole moments. Measurements of the hyperfine structures and isotope shifts in the atomic spectra of radioactive nuclei provide unique insight into the evolution of the nuclear macroscopic shape and microscopic structure. These measurements can be made with high precision and high sensitivity and applied directly on-line at radioactive nuclear beam facilities. Recent measurements, advances at facilities and the future direction of the field are reviewed. A summary of experimental data is presented. peerReviewed
Microscopic description of even-even nuclei in the mass A = 130 region
1986
Abstract We present a systematic study of even-even nuclei in the mass A = 130 region using a microscopic nuclear structure model, in which the nuclear wave functions are approximated by linear combinations of number- and spin-projected zero-quasiparticle and two-quasipartile determinants obtained from a self-consistent Hartree-Fock-Bogoliubov mean field. With a fixed hamiltonian, being a slightly renormalized Brueckner G-matrix based on the Bonn potential the model is able to reproduce the main trends of empirical energy and electromagnetic properties of the transitional, soft nuclei in the region. The empirical nature of the crossing ( πh 11 2 ) 2 and ( vh 11 2 ) 2 superbands in Ce and Ba…
β-Decay Studies Close to the N=82 r-process Path
2005
New half-lives for neutron-rich ruthenium, rhodium and palladium isotopes close to the r-process path along the N=82 closed shell have been measured at the National Superconducting Cyclotron Laboratory at Michigan State University. The studied isotopes are close to the critical A=118-126 mass region in the astrophysical r-process, where incorrect nuclear structure development towards the shell closure may have the most pronounced effect on the abundances of elements produced. Neutron-rich nuclei were produced by fragmentation of a 120-MeV per nucleon 136 Xe beam on Be and were separated by the A1900 fragment separator. The nuclei of interest were implanted into a double-sided Si strip detec…
Direct mass measurements of neutron-rich zirconium isotopes up toZr104
2004
Atomic masses of radioactive zirconium isotopes from {sup 96}Zr to {sup 104}Zr have been measured with a relative accuracy of {<=}5x10{sup -7} using a Penning trap coupled to the ion guide isotope separator on-line system. The obtained two-neutron separation energies show strong local correlation in relation to the shape change and shape coexistence between N=58 and 60.
Resolution of nuclear ground and isomeric states by a Penning trap mass spectrometer.
1992
Ground and isomeric states of a nucleus have been resolved for the first time by mass spectrometry. Measurements on $^{78}\mathrm{Rb}^{\mathit{m},}$g and $^{84}\mathrm{Rb}^{\mathit{m},}$g were performed using a tandem Penning trap mass spectrometer on-line with the isotope separator ISOLDE/CERN. The effects of ion-ion interaction were investigated for two ion species differing in mass and stored simultaneously in the trap.
New information on β-delayed neutron emission from Be-12, Be-14
1999
17 pages, 3 tables, 5 figures, 1 appendix.-- PACS nrs.: 23.40.Hc; 27.20.+n.