magnetic moment

[paper] Isomer Shift and Magnetic Moment of the Long-Lived ½⁺ Isomer in ⁷⁹Zn: Signature of Shape Coexistence near ⁷⁸Ni

Isomer Shift and Magnetic Moment of the Long-Lived ½⁺ Isomer in ⁷⁹Zn: Signature of Shape Coexistence near ⁷⁸Ni

X.F. Yang et al.

Collinear laser spectroscopy is performed on the ⁷⁹Zn isotope at ISOLDE-CERN. The existence of a long-lived isomer with a few hundred milliseconds half-life is confirmed, and the nuclear spins and moments of the ground and isomeric states in ⁷⁹Zn, as well as the isomer shift are measured. From the observed hyperfine structures, spins I=9/2 and I=½ are firmly assigned to the ground and isomeric states. The magnetic moment μ(⁷⁹Zn)=-1.1866(10)μ_N, confirms the spin-parity I=9/2⁺ with a νg_9/2^-1 shell-model configuration, in excellent agreement with the prediction from large scale shell-model theories. The magnetic moment μ(^79mZn)=-1.0180(12)μ_N supports a positive parity for the isomer, with a wave function dominated by a 2h-1p neutron excitation across the N=50 shell gap. The large isomer shift reveals an increase of the intruder isomer mean square charge radius with respect to that of the ground state, δ2>^79,79m=+0.204(6) fm², providing first evidence of shape coexistence.

May 16, 2016 by Theo g factor 0

[preprint] Populating Low-Spin States in Radioactive Nuclei to Measure Magnetic Moments Using the Transient Field Technique

Populating Low-Spin States in Radioactive Nuclei to Measure Magnetic Moments Using the Transient Field Technique

D.A. Torres and F. Ramírez

arXiv: 1601.03602

The experimental study of magnetic moments for nuclear states near the ground state, I≥2, provides a powerful tool to test nuclear structure models. The study of magnetic moments in nuclei far away from the stability line is the next frontier in such studies. Two techniques have been utilized to populated low-spin states in radioactive nuclei: coulomb excitation reactions using radioactive nuclei, and the transfer of α particles to stable beams to populate low spin states in radioactive nuclei. A presentations of these two techniques, along with the experimental challenges presented for future uses with nuclei far away from the stability line, will be presented.

Jan 17, 2016 by Theo experiment g factor 0

[paper] Demonstration of the double Penning Trap technique with a single proton

Demonstration of the double Penning Trap technique with a single proton

A. Mooser et al.

doi: 10.1016/j.physletb.2013.05.012

Spin flips of a single proton were driven in a Penning trap with a homogeneous magnetic field.
For the spin-state analysis the proton was transported into a second Penning trap with
a superimposed magnetic bottle, and the continuous Stern–Gerlach effect was applied.
This first demonstration of the double Penning trap technique with a single proton suggests
that the antiproton magnetic moment measurement can potentially be improved by three
orders of magnitude or more.

Jun 4, 2013 by Theo experiment 0

[paper] Magnetic moments of the low-lying J^P = 1/2^–, 3/2^– Λ resonances within the framework of the chiral quark model

Magnetic moments of the low-lying J^P = 1/2^–, 3/2^– Λ resonances within the framework of the chiral quark model

A. Martinez Torres et al

doi: 10.1140/epja/i2012-12185-3

The magnetic moments of the low-lying spin-parity J^P = 1/2^–, 3/2^– Λ resonances, like, for example, Λ(1405)1/2^–, Λ(1520) 3/2^–, as well as their transition magnetic moments, are calculated using the chiral quark model. The results found are compared with those obtained from the nonrelativistic quark model and those of unitary chiral theories, where some of these states are generated through the dynamics of two hadron coupled channels and their unitarization.

Jan 6, 2013 by Theo theory 0

[paper] Hyperfine structure anomaly and magnetic moments of neutron deficient Tl isomers with I=9/2

Hyperfine structure anomaly and magnetic moments of neutron deficient Tl isomers with I=9/2

A.E. Barzakh et al.

doi: 10.1103/PhysRevC.86.014311

The hyperfine structure of 276.9-nm atomic transition has been studied by the resonant ionization spectroscopy method at mass-separator IRIS (Investigation of Radioactive Isotopes on Synchrocyclotron), Petersburg Nuclear Physics Institute (PNPI) for the odd Tl isomers with I=9/2 and A=187–197. A differential hyperfine structure anomaly for 6p²P_1/2 and 7s²S_1/2 atomic states in Tl isomers with I=9/2 has been determined. It is described by the recently developed theoretical approach fairly well. This enables one to recalculate the magnetic moments of ^187−193Tl^m(I=9/2) from previously measured hyperfine splittings for 7s²S_1/2 states and to determine for the first time the magnetic moments for ¹⁹⁷Tl^m and ¹⁹⁵Tl^m(I=9/2) from hyperfine splittings for 6p²P_1/2 states with properly taking into account the rather great hyperfine structure anomaly. Similar measurements with greater accuracy have been proposed for the other nuclear states in odd-odd Tl isotopes. These measurements could shed light on the nuclear magnetization distribution in these isotopes.

Jul 18, 2012 by Theo experiment g factor 0

[paper] Magnetic moments of K isomers as indicators of octupole collectivity

Magnetic moments of K isomers as indicators of octupole collectivity

N. Minkov and P. M. Walker

doi: 10.1140/epja/i2012-12080-y

The relation between the quadrupole-octupole deformation and the structure of high-K isomers in heavy even-even nuclei is studied through a reflection asymmetric deformed shell model including a BCS procedure with constant pairing interaction. Two-quasiparticle states with K^π=4⁻, 5⁻, 6⁻, 6⁺ and 7⁻ are considered in the region of actinide nuclei (U, Pu and Cm) and rare-earth nuclei (Nd, Sm and Gd). The behaviour of two-quasiparticle energies and magnetic dipole moments of these configurations is examined over a wide range in the plane of quadrupole and octupole deformations (&betal₂ and β₃. In all considered actinide nuclei, the calculations show that there is pronounced sensitivity of the magnetic moments to the octupole deformation. In the rare-earth nuclei, the calculations for ^154,156Gd show stronger sensitivity of the magnetic moment to the octupole deformation than in the other considered cases.

Jun 10, 2012 by Theo theory 0

[paper] Observation of ²³⁹Pu Nuclear Magnetic Resonance

Observation of ²³⁹Pu Nuclear Magnetic Resonance

H. Yasuoka et al.

doi: 10.1126/science.1220801

In principle, the spin-½ plutonium-239 (²³⁹Pu) nucleus should be active in nuclear magnetic resonance spectroscopy. However, its signal has eluded detection for the past 50 years. Here, we report observation of a ²³⁹Pu resonance from a solid sample of plutonium dioxide (PuO2) subjected to a wide scan of external magnetic field values (3 to 8 tesla) at a temperature of 4 kelvin. By mapping the external field dependence of the measured resonance frequency, we determined the nuclear gyromagnetic ratio ²³⁹γγ_n(PuO2)/2π to be 2.856&plusm;0.001 megahertz per tesla (MHz/T). Assuming a free-ion value for the Pu⁴⁺ hyperfine coupling constant, we estimated a bare ²³⁹γγ_n/2π value of ~2.29 MHz/T, corresponding to a nuclear magnetic moment of μ_n ≈ 0.15 μμ_N (where μ_N is the nuclear magneton).

May 28, 2012 by Theo experiment g factor 0

[paper] Direct Measurement of the Proton Magnetic Moment

Direct Measurement of the Proton Magnetic Moment

J. DiSciacca and G. Gabrielse

doi: 10.1103/PhysRevLett.108.153001

The proton magnetic moment in nuclear magnetons is measured to be μ_p/μ_N≡g/2=2.792 846±0.000 007, a 2.5 parts per million uncertainty. The direct determination, using a single proton in a Penning trap, demonstrates the first method that should work as well with an antiproton (p̅ ) as with a proton (p). This opens the way to measuring the p̅ magnetic moment (whose uncertainty has essentially not been reduced for 20 years) at least 103 times more precisely.

Apr 10, 2012 by Theo g factor 0

[paper] In-source laser spectroscopy of ^75,77,78Cu: Direct evidence for a change in the quasiparticle energy sequence in ^75,77Cu and an absence of longer-lived isomers in ⁷⁸Cu

In-source laser spectroscopy of ^75,77,78Cu: Direct evidence for a change in the quasiparticle energy sequence in ^75,77Cu and an absence of longer-lived isomers in ⁷⁸Cu

U. Köster et al.

doi: 10.1103/PhysRevC.84.034320

This paper describes measurements on the isotopes ^75,77,78Cu by the technique of in-source laser spectroscopy, at the ISOLDE facility, CERN. The role of this technique is briefly discussed in the context of this and other, higher resolution, methods applied to copper isotopes in the range ⁵⁷⁻⁷⁸Cu. The data, analyzed in comparison with previous results on the lighter isotopes ^59,63Cu, establish the ground-state nuclear spin of ^75,77Cu as 5/2 and yield their magnetic dipole moments as +1.01(5)μ_N and +1.61(5)μ_N, respectively. The results on ⁷⁸Cu show no evidence for long-lived isomerism at this mass number and are consistent with a spin in the range 3–6 and moment of 0.0(4) μ_N.

Sep 29, 2011 by Theo g factor 0

[paper] Hyperfine field and hyperfine anomalies of copper impurities in iron

Hyperfine field and hyperfine anomalies of copper impurities in iron

V. V. Golovko et al.

doi: 10.1103/PhysRevC.84.014323

A new value for the hyperfine magnetic field of copper impurities in iron is obtained by combining resonance frequencies from experiments involving β-NMR on oriented nuclei on ⁵⁹Cu, ⁶⁹Cu, and ⁷¹Cu with magnetic moment values from collinear laser spectroscopy measurements on these isotopes. The resulting value, i.e., B_hf(CuFe) = -21.794(10) T, is in agreement with the value adopted until now but is an order of magnitude more precise. It is consistent with predictions from ab initio calculations. Comparing the hyperfine field values obtained for the individual isotopes, the hyperfine anomalies in Fe were determined to be ⁵⁹Δ⁶⁹=0.15(9)% and ⁷¹Δ⁶⁹=0.07(11)%.

Jul 22, 2011 by Theo g factor 0

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