0000000000021601
AUTHOR
M. De Rydt
Spins and Magnetic Moments ofK49andK51: Establishing the1/2+and3/2+Level Ordering BeyondN=28
The ground-state spins and magnetic moments of $^{49,51}\mathrm{K}$ have been measured using bunched-beam high-resolution collinear laser spectroscopy at ISOLDE CERN. For $^{49}\mathrm{K}$ a ground-state spin $I=1/2$ was firmly established. The observed hyperfine structure of $^{51}\mathrm{K}$ requires a spin $Ig1/2$ and strongly suggests $I=3/2$. From its magnetic moment $\ensuremath{\mu}(^{51}\mathrm{K})=+0.5129(22){\ensuremath{\mu}}_{N}$ a spin-parity ${I}^{\ensuremath{\pi}}=3/{2}^{+}$ with a dominant $\ensuremath{\pi}1{d}_{3/2}^{\ensuremath{-}1}$ hole configuration was deduced. This establishes for the first time the reinversion of the single-particle levels and illustrates the prominen…
Nuclear Spins and Magnetic Moments ofCu71,73,75: Inversion ofπ2p3/2andπ1f5/2Levels inCu75
We report the first confirmation of the predicted inversion between the pi2p3/2 and pi1f5/2 nuclear states in the nu(g)9/2 midshell. This was achieved at the ISOLDE facility, by using a combination of in-source laser spectroscopy and collinear laser spectroscopy on the ground states of 71,73,75Cu, which measured the nuclear spin and magnetic moments. The obtained values are mu(71Cu)=+2.2747(8)mu(N), mu(73Cu)=+1.7426(8)mu(N), and mu(75Cu)=+1.0062(13)mu(N) corresponding to spins I=3/2 for 71,73Cu and I=5/2 for 75Cu. The results are in fair agreement with large-scale shell-model calculations.
Spin and Magnetic Moment ofMg33: Evidence for a Negative-Parity Intruder Ground State
We report on the first determination of the nuclear ground-state spin of $^{33}\mathrm{Mg}$, $I=3/2$, and its magnetic moment, $\ensuremath{\mu}=\ensuremath{-}0.7456(5)\text{ }{\ensuremath{\mu}}_{N}$, by combining laser spectroscopy with nuclear magnetic resonance techniques. These values are inconsistent with an earlier suggested 1 particle-1 hole configuration and provide evidence for a 2 particle-2 hole intruder ground state with negative parity. The results are in agreement with an odd-neutron occupation of the $3/2\text{ }[321]$ Nilsson orbital at a large prolate deformation. The discussion emphasizes the need of further theoretical and experimental investigation of the island of inver…
Spins and Magnetic Moments of $^{49}$K and $^{51}$K: establishing the 1/2$^+$ and 3/2$^+$ level ordering beyond $N$ = 28
The ground-state spins and magnetic moments of $^{49,51}$K have been measured using bunched-beam high-resolution collinear laser spectroscopy at ISOLDE-CERN. For $^{49}$K a ground-state spin $I = 1/2$ was firmly established. The observed hyperfine structure of $^{51}$K requires a spin $I > 1/2$ and from its magnetic moment $\mu(^{51}\text{K})= +0.5129(22)\, \mu_N$ a spin/parity $I^\pi=3/2^+$ with a dominant $\pi 1d_{3/2}^{-1}$ hole configuration was deduced. This establishes for the first time the re-inversion of the single-particle levels and illustrates the prominent role of the residual monopole interaction for single-particle levels and shell evolution.
Magnetic and quadrupole moments of neutron deficient 58-62Cu isotopes
Abstract This paper reports on the ground state nuclear moments measured in 58–62Cu using collinear laser spectroscopy at the ISOLDE facility. The quadrupole moments for 58–60Cu have been measured for the first time as Q ( Cu 58 ) = − 15 ( 3 ) efm 2 , Q ( Cu 59 ) = − 19.3 ( 19 ) efm 2 , Q ( Cu 60 ) = + 11.6 ( 12 ) efm 2 and with higher precision for 61,62Cu as Q ( Cu 61 ) = − 21.1 ( 10 ) efm 2 , Q ( Cu 62 ) = − 2.2 ( 4 ) efm 2 . The magnetic moments of 58,59Cu are measured with a higher precision as μ ( Cu 58 ) = + 0.570 ( 2 ) μ N and μ ( Cu 59 ) = + 1.8910 ( 9 ) μ N . The experimental nuclear moments are compared to large-scale shell-model calculations with the GXPF1 and GXPF1A effective i…
Nuclear charge radii of potassium isotopes beyond N=28
We report on the measurement of optical isotope shifts for 38, 39, 42, 44, 46–51 K relative to 47 K from which changes in the nuclear mean square charge radii across the N = 28 shell closure are deduced. The investigation was carried out by bunched-beam collinear laser spectroscopy at the CERN-ISOLDE radioactive ion-beam facility. Mean square charge radii are now known from 37K to 51K, covering all ν f7/2-shell as well as all νp3/2-shell nuclei. These measurements, in conjunction with those of Ca, Cr, Mn and Fe, provide a first insight into the Z dependence of the evolution of nuclear size above the shell closure at N = 28
Experimental determination of anIπ=2−ground state inCu72,74
This article reports on the ground-state spin and moments measured in $^{72,74}\mathrm{Cu}$ using collinear laser spectroscopy at the CERN On-Line Isotope Mass Separator (ISOLDE) facility. From the measured hyperfine coefficients, the nuclear observables $\ensuremath{\mu}$(${}^{72}\mathrm{Cu})=\ensuremath{-}1.3472(10){\ensuremath{\mu}}_{N}$, $\ensuremath{\mu}({}^{74}\mathrm{Cu})=\ensuremath{-}1.068(3){\ensuremath{\mu}}_{N}$, $Q({}^{72}\mathrm{Cu})=+8(2) {\mathrm{efm}}^{2}$, $Q({}^{74}\mathrm{Cu})=+26(3) {\mathrm{efm}}^{2}$, $I({}^{72}\mathrm{Cu})=2$, and $I({}^{74}\mathrm{Cu})=2$ have been determined. Through a comparison of the measured magnetic moments with different models, the negative …
Proton-Neutron Pairing Correlations in the Self-Conjugate NucleusK38Probed via a Direct Measurement of the Isomer Shift
A marked difference in the nuclear charge radius was observed between the ${I}^{\ensuremath{\pi}}={3}^{+}$ ground state and the ${I}^{\ensuremath{\pi}}={0}^{+}$ isomer of $^{38}\mathrm{K}$ and is qualitatively explained using an intuitive picture of proton-neutron pairing. In a high-precision measurement of the isomer shift using bunched-beam collinear laser spectroscopy at CERN-ISOLDE, a change in the mean-square charge radius of $⟨{r}_{\mathrm{c}}^{2}⟩{(}^{38}{\mathrm{K}}^{m})\ensuremath{-}⟨{r}_{\mathrm{c}}^{2}⟩{(}^{38}{\mathrm{K}}^{g})=0.100(6)\text{ }\text{ }{\mathrm{fm}}^{2}$ was obtained. This is an order of magnitude more accurate than the result of a previous indirect measurement fr…
Nuclear Charge Radii ofMg21−32
Charge radii of all magnesium isotopes in the sd shell have been measured, revealing evolution of the nuclear shape throughout two prominent regions of assumed deformation centered on (24)Mg and (32)Mg. A striking correspondence is found between the nuclear charge radius and the neutron shell structure. The importance of cluster configurations towards N=8 and collectivity near N=20 is discussed in the framework of the fermionic molecular dynamics model. These essential results have been made possible by the first application of laser-induced nuclear orientation for isotope shift measurements.
Nuclear spins, magnetic moments, and quadrupole moments of Cu isotopes fromN=28toN=46: Probes for core polarization effects
Measurements of the ground-state nuclear spins and magnetic and quadrupole moments of the copper isotopes from $^{61}\mathrm{Cu}$ up to $^{75}\mathrm{Cu}$ are reported. The experiments were performed at the CERN online isotope mass separator (ISOLDE) facility, using the technique of collinear laser spectroscopy. The trend in the magnetic moments between the $N=28$ and $N=50$ shell closures is reasonably reproduced by large-scale shell-model calculations starting from a $^{56}\mathrm{Ni}$ core. The quadrupole moments reveal a strong polarization of the underlying Ni core when the neutron shell is opened, which is, however, strongly reduced at $N=40$ due to the parity change between the $\mat…
Spin and magnetic moment of23Mg
A negative magnetic moment of 23Mg has been determined by collinear laser spectroscopy at CERN-ISOLDE. The absolute value is in agreement with previous measurements by nuclear magnetic resonance while the sign points at high-seniority configurations. The result is consistent with shell-model predictions for nuclei with valence nucleons in the sd shell. ispartof: Journal of Physics G, Nuclear and Particle Physics vol:44 issue:7 status: published
Shell structure of potassium isotopes deduced from their magnetic moments
\item[Background] Ground-state spins and magnetic moments are sensitive to the nuclear wave function, thus they are powerful probes to study the nuclear structure of isotopes far from stability. \item[Purpose] Extend our knowledge about the evolution of the $1/2^+$ and $3/2^+$ states for K isotopes beyond the $N = 28$ shell gap. \item[Method] High-resolution collinear laser spectroscopy on bunched atomic beams. \item[Results] From measured hyperfine structure spectra of K isotopes, nuclear spins and magnetic moments of the ground states were obtained for isotopes from $N = 19$ up to $N = 32$. In order to draw conclusions about the composition of the wave functions and the occupation of the …
g factors of $^{31,32,33}$Al: Indication for intruder configurations in the $^{33}$Al ground state
Abstract The g factors of 31,32,33 Al have been measured using the β -nuclear magnetic resonance ( β -NMR) technique on spin-polarized beams produced in the fragmentation of a 36 S (77.5 MeV/u) beam on a 9 Be target. Nearly pure beams of Al ( Z = 13 ) isotopes were selected with the high-resolution fragment separator LISE at GANIL. An asymmetry as high as 6% has been observed in the β -NMR curve for 32 Al implanted in a Si single crystal. The magnetic moment of the N = 20 nucleus 33 Al is obtained for the first time: μ ( Al 33 , I π = 5 / 2 + ) = 4.088 ( 5 ) μ N , while those of 31,32 Al are obtained with improved accuracy: μ ( Al 31 , I π = 5 / 2 + ) = 3.830 ( 5 ) μ N and μ ( Al 32 , I π =…