Search results for "Isotone"
showing 10 items of 16 documents
Shell evolution of $N=40$ isotones towards $^{60}$Ca: First spectroscopy of $^{62}$Ti
2020
7 pags., 4 figs., 1 tab.
What can be learnt about nuclear polarization from a consistency analysis ofe ? cross sections and muonic X-rays for208Pb and the isotone pair209Bi/2…
1977
A joint analysis of recent electron scattering cross sections and muonic atom X-ray energies is performed for208Pb and the isotone pair209Bi/208Pb. From the compatibility of the experimental data one can learn about the nuclear polarisation correction. However, we find this information not to be as accurate as other authors claimed when we take into consideration the ambiguities in the treatment of the corrections of the higher levels.
Level scheme ofZr101and structure of theN=61 Sr, Zr, and Mo isotones
1995
The neutron-rich nucleus $_{40}^{101}\mathrm{Zr}_{61}$ has been studied at the isotope separator ISOLDE via the \ensuremath{\beta} decay of $^{101}\mathrm{Y}$. A detailed level scheme has been obtained from \ensuremath{\gamma}-ray singles, \ensuremath{\gamma}-\ensuremath{\gamma}-t and \ensuremath{\beta}-\ensuremath{\gamma}-t coincidence measurements. The level structure of $^{101}\mathrm{Zr}$ is similar to that of its isotone $^{103}\mathrm{Mo}$ showing that, in contrast to their Sr neighbors, the Zr isotopes do not reach maximum of deformation immediately at its onset. This result is rather well reproduced by particle-rotor coupling calculations. A level systematics for the deformed N=61 i…
Five-valence-protonN=82isotone137Cs
1999
Yrast excitations in the N=82 isotone {sup 137}Cs have been identified for the first time in thick-target {gamma}-ray coincidence measurements for the system {sup 232}Th+{sup 136}Xe using the Gammasphere array. The {sup 137}Cs nuclei were produced in deep inelastic one-proton-transfer reactions. By-products of the main investigation were two well-developed rotational bands which were identified in heavy reaction partner products complementary to {sup 137}Cs and are tentatively assigned to the little studied nucleus {sup 231}Ac. There was no difficulty in placing the 11 observed {sup 137}Cs transitions in a yrast level scheme extending to an I{sup {pi}}=(31/2{sup {minus}}) level at 5494 keV.…
Isomers inPd128andPd126: Evidence for a Robust Shell Closure at the Neutron Magic Number 82 in Exotic Palladium Isotopes
2013
The level structures of the very neutron-rich nuclei $^{128}\mathrm{Pd}$ and $^{126}\mathrm{Pd}$ have been investigated for the first time. In the $r$-process waiting-point nucleus $^{128}\mathrm{Pd}$, a new isomer with a half-life of $5.8(8)\text{ }\text{ }\ensuremath{\mu}\mathrm{s}$ is proposed to have a spin and parity of ${8}^{+}$ and is associated with a maximally aligned configuration arising from the ${g}_{9/2}$ proton subshell with seniority $\ensuremath{\upsilon}=2$. For $^{126}\mathrm{Pd}$, two new isomers have been identified with half-lives of 0.33(4) and $0.44(3)\text{ }\text{ }\ensuremath{\mu}\mathrm{s}$. The yrast ${2}^{+}$ energy is much higher in $^{128}\mathrm{Pd}$ than in…
Experimental Evidence for Shape Coexistence in 97Sr59 and Implications for the Structure of the Odd-Odd Isotone 98Y
1988
Experimental evidence for shape coexistence in the odd-mass N=59 isotone 97Sr is presented. The ground state and the lowest excited levels of 97Sr are shown to be spherical, whereas a rotational band based on a state at 585 keV has been identified. Three further levels of deformed origin are proposed. Nilsson-orbital assignments are supported by RPA shell-model calculations. These findings lead to a better understanding of the structure of the odd-odd N=59 isotone 98Y.
Electromagnetic Transition Rate Measurements in theN=80 Isotone,138Ce
2012
A study of intrinsic state halflife measurements in the N=80 nucleus 138Ce has been made using the 130Te(12C,4n)138Ce fusion evaporation reaction at beam energy of 56 MeV. The fast-timing gamma-ray coincidence method was used with a mixed LaBr3(Ce)-HPGe array to establish the lifetimes of the yrast 6+ state at 2294 keV, the Iπ=5− state at 2218 keV, the Iπ=11+ state at 3943 keV and the 14+ state at that at 5312 keV, all of which are in the sub nanosecond regime. Reduced transition probabilities have been calculated for the electromagnetic decays from these states.
Half-Life Systematics across theN=126Shell Closure: Role of First-Forbidden Transitions in theβDecay of Heavy Neutron-Rich Nuclei
2014
This Letter reports on a systematic study of β-decay half-lives of neutron-rich nuclei around doubly magic Pb208. The lifetimes of the 126-neutron shell isotone Pt204 and the neighboring Ir200-202, Pt203, Au204 are presented together with other 19 half-lives measured during the "stopped beam" campaign of the rare isotope investigations at GSI collaboration. The results constrain the main nuclear theories used in calculations of r-process nucleosynthesis. Predictions based on a statistical macroscopic description of the first-forbidden β strength reveal significant deviations for most of the nuclei with N<126. In contrast, theories including a fully microscopic treatment of allowed and first…
Coulomb Excitation of Neutron-Rich Zn Isotopes: First Observation of the21+State inZn80
2007
Neutron-rich, radioactive Zn isotopes were investigated at the Radioactive Ion Beam facility REX-ISOLDE (CERN) using low-energy Coulomb excitation. The energy of the 2(1)+ state in 78Zn could be firmly established and for the first time the 2+ --> 0(1)+ transition in 80Zn was observed at 1492(1) keV. B(E2,2(1)+ --> 0(1)+) values were extracted for (74,76,78,80)Zn and compared to large scale shell model calculations. With only two protons outside the Z=28 proton core, 80Zn is the lightest N=50 isotone for which spectroscopic information has been obtained to date. Two sets of advanced shell model calculations reproduce the observed B(E2) systematics. The results for N=50 isotones indicate a g…
Assignment of levels in 208Fr and 10- isomers in the odd-odd isotones 206At and 208Fr
2009
Excited states in 208 Fr have been identified using the 197 Au( 16 O, 5n) 208 Fr reaction and a variety of time-correlated γ-ray and conversion electron spectroscopic techniques. Transitions above and below a τ = 623(16) ns 10 − isomer are placed in the level scheme. This isomer is analogous to that observed in the odd-odd isotone 206 At for which additional spectroscopic information is also obtained, including a precise lifetime of τ = 1173(30) ns. The γ-rays assigned to 208 Fr are the same as the main transitions erroneously assigned to 209 Fr in previous work.