NMR

[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 239γγn(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 239γγn/2π value of ~2.29 MHz/T, corresponding to a nuclear magnetic moment of μn ≈ 0.15 μμN (where μN is the nuclear magneton).

[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)μN. 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.