136 research outputs found
Binding energies of ground and isomeric states in neutron-rich ruthenium isotopes: measurements at JYFLTRAP and comparison to theory
We report on precision mass measurements of Ru performed with
the JYFLTRAP double Penning trap mass spectrometer at the Accelerator
Laboratory of University of Jyv\"askyl\"a. The phase-imaging
ion-cyclotron-resonance technique was used to resolve the ground and isomeric
states in Ru and enabled for the first time a measurement of the
isomer excitation energies, Ru keV and
Ru keV. The ground state of Ru was measured
using the time-of-flight ion-cyclotron-resonance technique. The new mass-excess
value for Ru is around 36 keV lower and 7 times more precise than the
previous literature value. With the more precise ground-state mass values, the
evolution of the two-neutron separation energies is further constrained and a
similar trend as predicted by the BSkG1 model is obtained up to the neutron
number .Comment: 12 pages, 9 figures, submitted to Physical Review
High-precision measurements of low-lying isomeric states in In with JYFLTRAP double Penning trap
Neutron-rich In isotopes have been studied utilizing the double
Penning trap mass spectrometer JYFLTRAP at the IGISOL facility. Using the
phase-imaging ion-cyclotron-resonance technique, the isomeric states were
resolved from ground states and their excitation energies measured with high
precision in In. In In, the states were
separated and their masses were measured while the energy difference between
the unresolved and states, whose presence was confirmed by
post-trap decay spectroscopy was determined to be keV. In addition,
the half-life of Cd, s, was extracted.
Experimental results were compared with energy density functionals, density
functional theory and shell-model calculations.Comment: 11 pages, 7 figure
First investigation on the isomeric ratio in multinucleon transfer reactions: Entrance channel effects on the spin distribution
The multinucleon transfer (MNT) reaction approach was successfully employed
for the first time to measure the isomeric ratios (IRs) of Po
(25/2) isomer and its (9/2) ground state at the IGISOL facility using a
945 MeV Xe beam impinged on Bi and Pb targets. The
dominant production of isomers compared to the corresponding ground states was
consistently revealed in the -decay spectra. Deduced IR of Po
populated through the Xe+Pb reaction was found to enhance
1.8-times than observed for Xe+Bi. State-of-the-art
Langevin-type model calculations have been utilized to estimate the spin
distribution of an MNT residue. The computations qualitatively corroborate with
the considerable increase in IRs of Po produced from Xe+Pb compared to Xe+Bi. Theoretical investigations indicate
a weak influence of target spin on IRs. The enhancement of the Po
isomer in the Xe+Pb over Xe+Bi can be
attributed to the different proton ()-transfer production routes.
Estimations demonstrate an increment in the angular momentum transfer,
favorable for isomer production, with increasing projectile energy. Comparative
analysis indicates the two entrance channel parameters, projectile mass and
-transfer channels, strongly influencing the population of the high-spin
isomer of Po (25/2). This is the first experimental and theoretical
investigation on the IRs of nuclei produced via different channels of MNT
reactions, with the latter quantitatively underestimating the former by a
factor of two.Comment: 5 figure
Nuclear charge radius of Al and its implication for V in the quark-mixing matrix
Collinear laser spectroscopy was performed on the isomer of the aluminium
isotope Al. The measured isotope shift to Al in the
3s^{2}3p\;^{2}\!P^\circ_{3/2} \rightarrow 3s^{2}4s\;^{2}\!S_{1/2} atomic
transition enabled the first experimental determination of the nuclear charge
radius of Al, resulting in =\qty{3.130\pm.015}{\femto\meter}. This
differs by 4.5 standard deviations from the extrapolated value used to
calculate the isospin-symmetry breaking corrections in the superallowed
decay of Al. Its corrected value, important for the
estimation of in the CKM matrix, is thus shifted by one standard
deviation to \qty{3071.4\pm1.0}{\second}.Comment: 5 pages, 2 figures, submitted to Phys. Rev. Let
Laser Spectroscopy of Neutron-Rich Tin Isotopes: A Discontinuity in Charge Radii across the N=82 Shell Closure
The change in mean-square nuclear charge radii ÎŽâšr2â© along the even-A tin isotopic chain 108â134Sn has been investigated by means of collinear laser spectroscopy at ISOLDE/CERN using the atomic transitions 5p2â1S0â5p6âs1P1 and 5p2â3P0â5p6sâ3P1. With the determination of the charge radius of 134Sn and corrected values for some of the neutron-rich isotopes, the evolution of the charge radii across the N=82 shell closure is established. A clear kink at the doubly magic 132Sn is revealed, similar to what has been observed at N=82 in other isotopic chains with larger proton numbers, and at the N=126 shell closure in doubly magic 208Pb. While most standard nuclear density functional calculations struggle with a consistent explanation of these discontinuities, we demonstrate that a recently developed Fayans energy density functional provides a coherent description of the kinks at both doubly magic nuclei, 132Sn and 208Pb, without sacrificing the overall performance. A multiple correlation analysis leads to the conclusion that both kinks are related to pairing and surface effects
High- K three-quasiparticle isomers in the proton-rich nucleus 129 Nd
Three three-quasiparticle isomers, one at an excitation energy of 2.3 MeV with T1/2=0.48(4)ÎŒs, and two shorter-lived with unknown half-lives at slightly lower energies have been identified in Nd129 using the MARA + JUROGAM 3 setup and the recoil tagging technique. All three isomers present decay patterns characteristic of high-K isomers. The known 6.7 s ÎČ-decaying isomer previously assigned to the 5/2+ level is now assigned to the new 7/2- ground state. A new low-spin 5/2+ isomeric state with a half-life of a few tens of nanoseconds has been identified, while a previously known 2.6 s ÎČ-decay activity was assigned to the band head of the Îœ1/2+[411] band. The transitions depopulating the high-K isomers to low-lying states also establish the relative energies of three low-lying one-quasiparticle bands, leading to a new spin-parity assignment of 7/2- to the ground state of Nd129. The partial half-lives of the depopulating transitions suggest spin-parities 21/2+, 19/2+, and 17/2+ for the three high-K isomers. The properties of the band built on the 21/2+ isomeric state suggest a one neutron-two proton configuration. Based on the results of extensive calculations with different models, we also assign one neutron-two proton configurations to the 19/2+ and 17/2+ isomeric states. The assigned configurations of the 17/2+ and 21/2+ isomeric states involve the Ï9/2+[404] orbital, which is identified in three-quasiparticle bands of proton-rich Aâ130 nuclei
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