Magnetic moment of beta-emitting41Sc(Iπ=7/2−) and knight shift in Pt metal

The nuclear magnetic moment of⁴¹Sc(I^π=7/2⁻, T_l/2=0.59sec) was remeasured, and the precision of the value was improved about 10 times compared with the previously known one. The value was determined to be |μ(⁴¹Sc;I^π=7/2)|=(5.4305±0.0018) nm. Comparing the value with the previously known NMR of the nuclei in Pt, the knight shift, K=−(0.4±5.3)·10⁻⁴ was determined.     

Beta-NMR detection of beta-emitting fragment43Ti

NMR on the beta emitter⁴³Ti has been observed by use of the -NMR technique. From the observed NMR spectrum, the magnetic moment of⁴³Ti was determined to be || =0.85±0.02 µ_N. The value is significantly quenched from the single particle value –1.91 µ_N, which shows a strong effect resulting from meson-exchange currents andconfiguration mixing.     

The magnetic moment of the 19/2− isomer in85Rb

The magnetic moment of the 19/2⁻ isomer in⁸⁵Rb has been measured by means of the TDPAD method providing μ=+1.3(4)μ_N. From this value the dominating three-quasiparticle structure πp _3/2 ⁻¹ pg _9/2 ⁻² has been deduced for this state.     

Quadrupole moment of the doubly closed shell +1 nucleon nucleus41Sc(Iπ=7/2−)

The nuclear electric quadrupole moment of⁴¹Sc(I^π=7/2⁻) was experimentally determined by use of the NMR detection in which the asymmetric β-ray distribution from spin polarized nuclei was monitored. The magnetic interaction of the state with high external magnetic field and the nuclear quadrupole interaction with the electric field gradient obtained in TiO₂ crystal were studied. The field gradient seen to the implanted⁴¹Sc was measured independently by the high field NMR detection on the stable isotope⁴⁵Sc located in the equivalent⁴¹Sc site with. |Q(⁴¹Sc;I^π=7/2⁻)|=(0.120±0.006) b was determined.     

Precise measurement of magnetic moment of short-lived β-emitting nuclei12B ( I π=1+, T 1/2=20.18 ms)

The spin polarized β-emitting nuclei¹²B (I ^π=1⁺,T _1/2=20.18 ms) were produced by the nuclear reaction¹¹B(d, p)¹²B and by the selection technique of the incident deuteron energy and the¹²B recoil angle following the nuclear reaction. The nuclear magnetic moment of the short-lived nuclei¹²B was measured by β-NMR with the β-NMR and β-NQR setup established for the first time in China. The nuclear magnetic moment of¹²B was determined to be μ=0.99993±0.00048 nm org=0.99993±0.00048 after the precise correction of the Knight shift.     

The “island of inversion" from a nuclear moments perspective and the g factor of 35Si

This paper reviews recent results from electromagnetic moment measurements on isotopes in the island of inversion around N=20. The obtained moments on neutron rich Na, Mg, Al and Si isotopes allow to draw conclusions on the amount of intruder components in their ground state wave function, demonstrating a gradual transition from the normal sd-shell region into the island of inversion, starting at N=18 for Na, N=19 for Mg and N=20 for Al isotopes. A measurement of the ground state g factor of ³⁵Si (N=21), using a polarized fragment beam at GANIL, is discussed in more detail. The magnetic moment μ(³⁵Si, I^π= 7/2^-) = (-)1.638(4) μ_N is consistent with a normal ground state structure, dominated by a νf_7/2 neutron.     

Nuclear magnetic moment of 57Cu ground state

The nuclear magnetic moment of the ground state of ⁵⁷Cu(I^π = 3/2^-, T_1/2 = 196.3 ms) has been measured to be |μ(⁵⁷Cu)| = (2.00 ±0.05) μ_N using the β-NMR technique. Together with the known magnetic moment of the mirror partner ⁵⁷Ni, the spin expectation value was extracted as = -0.78 ± 0.13. Discrepancy between present results and shell model calculations in the full fp shell implies significant shell breaking at ⁵⁶Ni with the neutron number N = 28.     

Precise measurement of the magnetic moment of17F(I x =5/2+,T 1/2=64.5 s) and its hyperfine interactions in ionic crystals

Hyperfine interactions of β-emitting¹⁷F implanted in single crystals of NaF and CaF₂ were studied. The nuclear magnetic moment of theT ^π=5/2⁺ state was determined with an improved precision to be |μ(¹⁷F;π=5/2⁺,T _1/2=64.5s|=4.72130±0.00025. nm. Isoscalar magnetic moments of the doubly closed shell ±1 nucleon nuclei around mass number 16 were derived and the effective nucleon mass in the nucleus was discussed.     

Precise measurement of the magnetic moment of doubly closed shell − 1 nucleon nucleus15O(I π1/2−,T 1/2=122 s)

The magnetic moment of¹⁵O(I=1/2^–,T _1/2=122 s) has been measured precisely by use of the -NMR detection of¹⁵O in TiO₂ as, |(¹⁵O; 1/2^–)|=0.71951 (12) µ_N. The effective nucleon mass in the nuclei around mass number 16 was discussed using the isoscalar moment deduced in connection with the magnetic moment of¹⁵N.     

Nuclear moments around the Z=40 shell closure:91mY,95Zr and97Nb

Magnetic moments around the Z=40 shell closure have been established using nuclear magnetic resonance on oriented nuclei (NMR/ON) in iron. From the resonance frequencies we established |μ(⁹¹Y;9/2⁺)|=5.96(6)μ_N, |μ(⁹⁵Zr;5/2⁺)|= 1.103(23)μ_N, | μ(⁹⁷Nb;9/2⁺)| = 6.153(5)μ_N. From the electric quadrupole alignement of⁹⁵Zr+⁹⁵Nb in a Zr single crystal Q(⁹⁵Zr)=+0.29(5)b and Q(⁹⁵Nb)<0 have been derived. The results obtained are discussed using the Nilsson deformed single particle model. It is shown that for certain deformation regions, a measurement of the magnetic moment can give information on the nuclear quadrupole deformation. the NICOLE-ISOLDE Collaboration, CERN     

On-line resonance of116Sbg cryogenically oriented at the DOLIS-COLD facility

The magnetic moment of¹¹⁶Sb^g(t_1/2=16 m, I=3⁺) has been measured to be ¦¦=2.716(7)_N using the technique of NMR/ON on nuclei oriented at low temperatures in an iron host, on-line at the DOLIS-COLD facility, Daresbury. The measured moment can be well interpreted using empirical magnetic moments of neighbouring odd-A antimony and tin nuclei. The change in I=3⁺ moments between^116–120Sb is well accounted for by the variation in the odd neutron contribution, the odd proton acting as a spectator.     

Nuclear magnetic moment of 12 d 11/2− 131mXe

NMR-ON measurements were performed on^131mXe (I=11/2^–; T_1/2=12.0 d) in Fe, the sample being prepared by recoil implantation after the¹³⁰Te(,3n)^131mXe compound reaction at E=40 Mev. The hyperfine splitting _NB_HF/h¦, extrapolated to zero external magnetic field, was found to be 209.9(1) MHz. Taking B_HF=+1523(8) kG for the hyperfine field of XeFe, the magnetic moment of^131mXe is deduced to be (–)0.994(5) _N. As a byproduct, the zero-field hyperfine splitting of^129mXe (I=11/2^–; T_1/2=8.9d) in Fe was measured as 188.1(1) MHz, with which a magnetic moment of (–)0.891(5) _N is deduced for^129mXe.     

Charge radii and shape transitions in short-lived Hg,Au and Pt isotopes

The hyperfine structure and the isotope shift of very neutron-deficient Au and Pt isotopes have been determined at the on-line isotope separator ISOLDE/CERN by resonance ionization mass spectroscopy combined with pulsed-laser induced desorption of the implanted radioactive sample. The changes of the mean-square charge radii were determined for the isotopes¹⁸⁴Au (T_1/2=53 s) and¹⁸³Au (T_1/2=42 s) as well as for 15 isotopes of platinum in the range between¹⁹⁸Pt (stable) and¹⁸³Pt (T_1/2=6.5 min). The strong deformation of¹⁸⁵Au (|β₂|≃0.25) persits down to¹⁸³Au. In¹⁸³Pt nearly the same value of |β₂| is reached but the deformation is build up rather smoothly in contrast to the neighbouring isotopes of gold and mercury. The magnetic moment of¹⁸³Pt was found to be μ₁=+0.51(3)μ _N .     

High-spin states of<Superscript>125</Superscript>Sb: Particle-core excitation coupling

Excited states of¹²⁵Sb have been studied using in-beam γ spectroscopy techniques via the¹²⁴Sn(⁷Li, α2n) reaction at a beam energy of 32 MeV. A high-spin level scheme including 21 new γ-transitions and 14 new excited states have been established. Three isomers have been identified at 1970, 2110 and 2471 keV and the ranges of their half-lives have been estimated from the delayed coincidence data. The level structure of¹²⁵Sb is discussed in terms of particle-core excitation coupling. With the help of empirical shell model calculations the three isomers are proposed to have three-quasiparticle πg_7/2⊗v(h _11/2 s _1/2)₅₋, πg_7/2⊗v(h _11/2 d _3/2)₇₋ and πg_7/2⊗v(h ₁₁^2/2)₁₀ ⁺ configurations, respectively.     

Anomalous anisotropies and field dependencies of the muon Knight shift and the relaxation rate in monocrystalline Bi

The angular dependence of the muon Knight shift,K _μ, and the muon relaxation rate in Bi at 11 K were measured in external magnetic fields up to 1 T. BothK _μ and the second moment,M ₂, are field dependent and involveP ₄ ⁰(cos θ) andP ₄ ³(cos θ) terms in the angular dependence. The Knight shift behaviour is discussed in terms of the dipole-dipole interaction and the de Haas-van Alphen effect, a consistent interpretation was not achieved in either case. The field dependence ofM ₂ is in complete contrast to the second moment calculations and points to a field dependent redistribution of the charge distribution around the interstitial site.     

Detection on NMR via the anisotropy of X-rays (X-NMR-ON)

Nuclear magnetic resonance on oriented nuclei has been detected for the first time via the destruction of the anisotropy of characteristic L_x-rays. The new method can be applied to isomeric states which decay only via highly converted transitions, for which the standard NMR-ON technique — detection of NMR via the anisotropy of -rays — is not applicable. The X-NMR-ON technique has been used to measure the magnetic hyperfine splitting of^193mpt (I=1322⁺; E=149.8 keV; T_1/2= 4.3 d) to be ¦ g _NB_HF/h¦=111.3 (3) MHz. with the known hyperfine field of –1280(27) kG the magnetic moment of^193mpt is deduced to be ¦¦=0.7417(14) _N. This magnetic moment differs strongly from the known magnetic moments of the 13/2⁺ isomeric states in Hg and Pb and^195mPt.     

μ + Knight shift and spin relaxation in indium single crystalKnight shift and spin relaxation in indium single crystal

μ ⁺ SR measurements have been performed in a single crystal indium sample between 12 K and 300 K with a stroboscopic μSR spectrometer. The muonic Knight shiftK _μ and the muonic depolarization rate σ were obtained for various angles θ between the tetragonal crystallinec-axis and the direction of the external field. The isotropic part ofK _μ is only weakly temperature dependent and is consistent with the estimated Pauli spin susceptibility value. At a temperature of 12 K the angular dependence ofM ₂ (the second moment of the field distribution at the muon, obtained from the measured σ(θ) values) allows a clear determination of the muon location — the symmetric tetrahedral site. The observed anisotropicK _μ cannot be explained by the dipoles at the In atoms responsible for the bulk magnetic susceptibility but probably originates from an anisotropic Pauli spin susceptibility.     

Isomeric states in 214Th and 213Th

Isomeric states in ²¹⁴Th and ²¹³Th were identified by means of γ -rays measured in delayed coincidence with the implanted evaporation residues. These were produced in irradiations of ¹⁶⁴Dy with ⁵⁴Cr projectiles and separated in-flight by the velocity filter SHIP. An isomeric state of I ^π = 8⁺ with a half-life of (1.24±0.12) μs was identified in ²¹⁴Th . The configuration π[1h _9/2 ⊗ 2f _7/2] was assigned to this state. An isomeric state with a half-life of (1.4±0.4) μs was observed in ²¹³Th . Tentatively it was assigned to an I ^π = 13/2⁺ state.     

Transferred hyperfine field in the pseudo-binary compound Y(Fe,Mn)2

The NMR of⁸⁹Y in Y(Fe_1−xMn_x)₂ has been observed. Two kinds of Mn moments were estimated by analyzing the⁸⁹Y hyperfine field: (1) the low spin state with about 0.6 μ_B in antiparallel to Fe moment and (2) the high spin state with about 2.8 μ_B in parallel to Fe moment. The magnetizations estimated from NMR results are in good agreement with those of magnetization measurements.     

Magnetic dipole moment of127Sb by NMR/ON

The technique of NMR on oriented nuclei has been applied to¹²⁷Sb to measure the magnetic dipole moment of the¹²⁷Sb ground state. Resonant destruction of gamma-ray anisotropy from¹²⁷Sb^g (I =7/2⁺) has been observed at 139.6(2) MHz forB _app=0.30(1) T andat 138.7(1) MHz forB _app=0.25(1) T. The deduced magnetic moment is ||=2.697(6) µ_N.