experiment

[paper] g factor of the ⁴⁴Cl ground state: Probing the reduced Z=16 and N=28 gaps

g factor of the ⁴⁴Cl ground state: Probing the reduced Z=16 and N=28 gaps

M. De Rydt et al.

The g factor of the ⁴⁴Cl ground state is measured at the LISE fragment separator at the Grand Acclérateur National d’Ions Lourds (GANIL) using the β nuclear magnetic resonance technique, resulting in g(⁴⁴Cl)=(-)0.2749(2). An analysis of the g factor value and of the theoretical level scheme in the shell-model framework reveals the presence of odd-proton s_1/2 configurations and neutron excitation across the N=28 shell gap in the ground state of ⁴⁴Cl. In addition, the measured g factor strongly supports a 2^– spin assignment for the ⁴⁴Cl ground state.

Mar 19, 2010 by Theo experiment g factor theory 0

[paper] Nuclear ground-state spin and magnetic moment of ²¹Mg

Nuclear ground-state spin and magnetic moment of ²¹Mg

J. Krämer et al.

doi: 10.1016/j.physletb.2009.06.063

We present the results of combined laser spectroscopy and nuclear magnetic resonance studies of ²¹Mg. The nuclear ground-state spin was measured to be I=5/2 with a magnetic moment of &mul;=−0.983(7)μ_N. The isoscalar magnetic moment of the mirror pair is evaluated and compared to the extreme single-particle prediction and to nuclear shell-model calculations. We determine an isoscalar spin expectation value of 〈σ〉=1.15(2), which is significantly greater than the empirical limit of unity given by the Schmidt values of the magnetic moments. Shell-model calculations taking into account isospin non-conserving effects, are in agreement with our experimental results.

Aug 3, 2009 by Theo experiment 0

[paper] Hyperfine field of einsteinium in iron and nuclear magnetic moment of ²⁵⁴Es

Hyperfine field of einsteinium in iron and nuclear magnetic moment of ²⁵⁴Es

N. Severijns et al.

10.1103/PhysRevC.79.064322

The angular distributions of γ rays and α particles from oriented ²⁵⁰Bk, ^253,254Es, and ²⁵⁵Fm nuclei were investigated to extract hyperfine interaction information for these actinide impurities in an iron host lattice. The hyperfine field of einsteinium in iron was found to be |B_hf(EsFe̲ |)=396(32) T. With this value the magnetic moment of ²⁵⁴Es was then determined as |μ|=4.35(41) μ_N.

Jun 29, 2009 by Theo experiment 0

[paper] Doubly-magic nature of ⁵⁶Ni: Measurement of the ground state nuclear magnetic dipole moment of ⁵⁵Ni

Doubly-magic nature of ⁵⁶Ni: Measurement of the ground state nuclear magnetic dipole moment of ⁵⁵Ni

J.S. Berryman et al.

doi: 10.1103/PhysRevC.79.064305

The nuclear magnetic moment of the ground state of ⁵⁵Ni (I^π=3/2^–, T_1/2=204 ms) has been deduced to be |&mul(⁵⁵Ni)|=(0.976&plusminus;0.026) μ_N using the β-ray detecting nuclear magnetic resonance technique. Results of a shell model calculation in the full fp shell model space with the GXPF1 interaction reproduce the experimental value. Together with the known magnetic moment of the mirror partner ⁵⁵Co, the isoscalar spin expectation value was extracted as <Σσ_z>=0.91&plusminus;0.07. The <Σσ_z> shows a trend similar to that established in the sd shell. The present theoretical interpretations of both &mul(⁵⁵Ni) and <Σσ_z> for the T=1/2, A=55 mirror partners support the softness of the ⁵⁶Ni core.

Jun 5, 2009 by Theo experiment 0

[paper] g factors of first 2⁺ states of neutron-rich Xe, Ba, and Ce isotopes

g factors of first 2⁺ states of neutron-rich Xe, Ba, and Ce isotopes

C. Goodin et al.

10.1103/PhysRevC.79.034316

Using new techniques developed for measuring angular correlations with large detector arrays, the g factors of 2⁺ states in ^140,142Xe are measured for the first time by the method of correlation attenuation in randomly oriented magnetic fields. g factors in ¹⁴⁶Ba and ^146,148Ce are measured to establish the method by comparison with previous values. The results are discussed in terms of IBM-2 and rotation-vibration models.

Mar 26, 2009 by Theo experiment g factor 0

[paper] Ground-state electric quadrupole moment of ³¹Al

Ground-state electric quadrupole moment of ³¹Al

D. Nagae et al.

The ground-state electric quadrupole moment of ³¹Al(I^π=5/2⁺,T_1/2=644(25) ms) has been measured by means of β-ray-detected nuclear magnetic resonance spectroscopy using a spin-polarized ³¹Al beam produced in the projectile fragmentation reaction. The obtained Q moment, |Q_exp(³¹Al)|=112(32) e mb, is in agreement with conventional shell model calculations within the sd valence space. Previous results on the magnetic moment also support the validity of the sd model in this isotope, and thus it is concluded that ³¹Al is located outside of the island of inversion

Feb 18, 2009 by Theo experiment 0

[paper] Quadrupole moments of neutron-deficient ^20,21Na

Quadrupole moments of neutron-deficient ^20,21Na

K. Minamisono et al.

doi: 10.1016/j.physletb.2009.01.006

The electric-quadrupole coupling constant of the ground states of the proton drip line nucleus ²⁰Na (I^π=2⁺, T_1/2=447.9 ms) and the neutron-deficient nucleus ²¹Na (I^π=3/2⁺, T_1/2=22.49 s) in a hexagonal ZnO single crystal were precisely measured to be |eqQ/h|=690±12 kHz and 939±14 kHz, respectively, using the multi-frequency β-ray detecting nuclear magnetic resonance technique under presence of an electric-quadrupole interaction. An electric-quadrupole coupling constant of ²⁷Na in the ZnO crystal was also measured to be |eqQ/h|=48.4±3.8 kHz. The electric-quadrupole moments were extracted as |Q(²⁰Na)|=10.3±0.8 efm² and |Q(²¹Na)|=14.0±1.1 efm², using the electric-coupling constant of ²⁷Na and the known quadrupole moment of this nucleus as references. The present results are well explained by shell-model calculations in the full sd-shell model space.

Feb 16, 2009 by Theo experiment 0

[paper] g factor of the exotic N=21 isotope ³⁴Al: probing the N=20 and N=28 shell gaps at the border of the "island of inversion"

g factor of the exotic N=21 isotope ³⁴Al: probing the N=20 and N=28 shell gaps at the border of the "island of inversion"

P. Himpe et al.

doi: 10.1016/j.physletb.2007.11.017

For the first time the g factor of an isotope beyond N=20 near the "island of inversion" has been measured. A ³⁴Al radioactive beam was produced in a one-neutron pickup reaction on a ³⁶S primary beam at 77.5 MeV/u, providing a large spin-polarization for application of the β-Nuclear Magnetic Resonance (β-NMR) method. The measured g factor of ³⁴Al, |g|=0.539(2), combined with results from earlier β-decay studies, allows to firmly assign a ground state spin/parity 4⁻. Comparison to large scale shell model calculations reveals that a dominant amount of intruder components is needed in the ³⁴Al wave function to account for the observed large magnetic moment μ=(+)2.156(16)μ_N. This reveals Z=13 to be a true "transition number" between the normal Z=14 Si isotopes and the abnormal Z=12 Mg isotopes. The sensitivity of this odd–odd ground state dipole moment to the N=20, as well as the N=28 gap, reveals that both are significantly reduced, despite Z=13 being outside the conventional island of inversion.

Jan 10, 2008 by Theo experiment g factor 0

Blogroll

Tags