0000000000427486
AUTHOR
G. J. Lane
Identification of a millisecond isomeric state inCd81129via the detection of internal conversion and Compton electrons
Abstract The decay of an isomeric state in the neutron-rich nucleus 129 Cd has been observed via the detection of internal conversion and Compton electrons providing first experimental information on excited states in this nucleus. The isomer was populated in the projectile fission of a 238 U beam at the Radioactive Isotope Beam Factory at RIKEN. From the measured yields of γ -rays and internal conversion electrons, a multipolarity of E 3 was tentatively assigned to the isomeric transition. A half-life of T 1 / 2 = 3.6 ( 2 ) ms was determined for the new state which was assigned a spin of ( 21 / 2 + ) , based on a comparison to shell model calculations performed using state-of-the-art reali…
βdecay of semi-magicCd130: Revision and extension of the level scheme ofIn130
This work was supported by the Spanish Ministerio de Ciencia e Innovacion under contract FPA2011-29854-C04 and the Spanish Ministerio de Economia y Competitividad under Contract No. FPA2014-57196-C5- 4-P, the Generalitat Valenciana (Spain) under Grant No. PROMETEO/2010/101, the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) (NRF-2014S1A2A2028636, 2016K1A3A7A09005579), the Priority Centers Research Program in Korea (2009-0093817), OTKA Contract No. K-100835, JSPS KAKENHI (Grant No. 25247045), the European Commission through the Marie Curie Actions call FP7-PEOPLE-2011-IEF under Contract No. 300096, the US Department of Energy, Office of Nuclear Physic…
Evidence for Shears Bands in108Cd
High-spin states were populated in ${}^{108}\mathrm{Cd}$ using the ${}^{96}\mathrm{Zr}{(}^{16}\mathrm{O},4n)$ reaction at a beam energy of 72 MeV. Two magnetic dipole bands have been observed, both of which contain weak $E2$ crossover transitions. Lifetimes for the stronger of the two bands were measured via the Doppler shift attenuation method. The configuration assignment for this band has been determined from comparison with tilted axis cranking model calculations to be $\ensuremath{\pi}[{g}_{9/2}^{\ensuremath{-}3}{g}_{7/2}]\ensuremath{\bigotimes}\ensuremath{\nu}[{h}_{11/2}{(g}_{7/2}{d}_{5/2}{)}^{1}]$ and $\ensuremath{\pi}[{g}_{9/2}^{\ensuremath{-}3}{g}_{7/2}]\ensuremath{\bigotimes}\ensu…
Shape evolution in116,118Ru: Triaxiality and transition between the O(6) and U(5) dynamical symmetries
${}^{116}\mathrm{Ru}$ and ${}^{118}\mathrm{Ru}$ have been studied via $\ensuremath{\beta}$-delayed $\ensuremath{\gamma}$-ray spectroscopy of nuclei produced in fragmentation reactions at the Radioactive Ion-Beam Factory (RIBF) facility. Level schemes with positive-parity states up to spin $J=6$ have been constructed. The results have been discussed in terms of the interacting boson model, the algebraic collective model, and total Routhian surfaces. We conclude that the very neutron-rich nuclei still show many features associated with triaxial $\ensuremath{\gamma}$-soft nuclei, represented by the O(6) symmetry, but are approaching a spherical structure, the U(5) symmetry, with increasing neu…
Isomers inPd128andPd126: Evidence for a Robust Shell Closure at the Neutron Magic Number 82 in Exotic Palladium Isotopes
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…
Determination of beta-delayed neutron emission probability limits of rhodium isotopes by gamma-ray spectroscopy
9 pags., 5 figs., 5 tabs. -- 27th International Nuclear Physics Conference (INPC2019) 29 July - 2 August 2019, Glasgow, UK
Proton Shell Evolution below Sn132 : First Measurement of Low-Lying β -Emitting Isomers in Ag123,125
The β-delayed γ-ray spectroscopy of neutron-rich 123;125Ag isotopes is investigated at the Radioactive Isotope Beam Factory of RIKEN and the long-predicted 1/2¯ β-emitting isomers in 123;125Ag are identified for the first time. With the new experimental results, the systematic trend of energy spacing between the lowest 9/2+ and 1/2¯ levels is extended in Ag isotopes up to N = 78, providing a clear signal for the reduction of the Z = 40 subshell gap in Ag towards N = 82. Shellmodel calculations with the state-of-the-art VMU plus M3Y spin-orbit interaction give a satisfactory description of the low-lying states in 123;125Ag. The tensor force is found to play a crucial role in the evolution of…
Observation of a $\gamma$-decaying millisecond isomeric state in $^{128}$Cd$_{80}$
A. Jungclaus et al. -- 6 pags., 5 figs., 2 tabs. -- Open Access funded by Creative Commons Atribution Licence 4.0
1p3/2Proton-Hole State inSn132and the Shell Structure AlongN=82
5 pags. ; 3 figs. ; PACS numbers: 23.40.-s, 21.10.Pc, 27.60.+j, 21.60.Cs ; Taprogge, J., et al.
New isomers in $^{125}$Pd$_{79}$ and $^{127}$Pd$_{81}$: Competing proton and neutron excitations in neutron-rich palladium nuclides towards the $N = 82$ shell closure
The neutron-rich isotopes of palladium have attracted considerable interest in terms of the evolution of the N=82 neutron shell closure and its influence on the r-process nucleosynthesis. In this Letter, we present the first spectroscopic information on the excited states in Pd and Pd studied using the EURICA γ-ray spectrometer, following production via in-flight fission of a high-intensity U beam at the RIBF facility. New isomeric states with half-lives of 144(4) ns and 39(6) μs have been assigned spins and parities of (23/2 ) and (19/2 ) in Pd and Pd, respectively. The observed level properties are compared to a shell-model calculation, suggesting the competition between proton excitation…
Impact of shell evolution on Gamow-Teller β decay from a high-spin long-lived isomer in 127Ag
6 pags., 4 figs., 2 tabs.