Measurement Of Nuclear Magnetic Moments Research Articles

Prospective of nuclear magnetic moment measurements by photofission reactions at ELI-NP

Magnetic moment measurements of isomeric states in neutron-rich isotopes populated in photofission using γ-beam facility at the Extreme Light Infrastructure−Nuclear Physics (ELI-NP) laboratory aim at addressing many open questions related to the structure of the nuclei in A around 100 and 130 mass regions. The possibility of such measurements at ELI-NP is briefly discussed here using Geant4 Monte Carlo simulations. The present paper report the estimates of γ-beam profile at the target, fission fragment production rates and the possible target geometry.

Exploring the feasibility of magnetic moment measurements in the exotic 20C nucleus using LISE++ calculations

Nuclear magnetic moment measurements in neutron-rich isotopes require special techniques that have to be applied in the latest generation of RIB factories. Fragmentation reactions used in these labs can produce exotic species as secondary beams. Specialized fragment separators are used to optimize the production of secondary beams. In this work, a simulation code, LISE++, is used to explore the feasibility of a magnetic moment measurement in the exotic 20C nucleus, produced as a secondary beam in NSCL A1900 and RIKEN RIPS fragment separators, by optimizing the settings of operations in both.

Dynamic nuclear self-polarization for measurements of nuclear magnetic moments

Dynamic nuclear self-polarization (DYNASP) is a phenomenon observed in III–V semiconductors. When electrons of the valence band of a semiconductor are optically excited to the conduction band, a relaxation process of the conduction electrons induces a large nuclear polarization to suddenly occur below a critical temperature. This mechanism is useful for nuclear magnetic moment measurements of unstable nuclei implanted in semiconductors.

Magic Angle Spinning: A Historical Perspective

AbstractFor Abstract see ChemInform Abstract in Full Text.

Beta-NMR/ON on-line at the NICOLE facility, ISOLDE recent magnetic moment studies near double magic 68 Ni

The technique of β-NMR/ON and its use for measurement of nuclear magnetic moments is briefly reviewed. Recent magnetic moment measurements are reported on 67Ni and 67Cu. The relevance of magnetic moments of single-particle (hole) states for study of effects of configuration mixing and mesonic exchange currents is discussed.

Measurements of nuclear magnetic moments and electric quadrupole moments of Lu isotopes.

Nuclear magnetic resonance measurements were performed on the ground states of $^{169}\mathrm{Lu}$, $^{171}\mathrm{Lu}$, $^{172}\mathrm{Lu}$, $^{173}\mathrm{Lu}$, and $^{177}\mathrm{Lu}$ and on the $\frac{23}{{2}^{\ensuremath{-}}}$ isomeric state $^{177m}\mathrm{Lu}$. The radioactive isotopes were implanted into hcp Co single crystals using the mass separator ISOLDE at CERN. For $^{169}\mathrm{Lu}$, $^{171}\mathrm{Lu}$, $^{172}\mathrm{Lu}$, $^{173}\mathrm{Lu}$, and $^{177}\mathrm{Lu}$ the quadrupole subresonance structure could be resolved well. With the magnetic hyperfine fields and the electric field gradient of $\mathrm{Lu}Co(\mathrm{hcp})$ derived from the results on $^{177}\mathrm{Lu}$, the magnetic moments and electric quadrupole moments of $^{169}\mathrm{Lu}$, $^{171}\mathrm{Lu}$, $^{172}\mathrm{Lu}$, and $^{173}\mathrm{Lu}$ were determined. The nuclear moments of the high-spin isomer $^{177m}\mathrm{Lu}$ were determined with a resonance-offset technique.

New developments and trends in NMR-ON

New developments and new trends in NMR-ON are presented, especially in the context of precise measurements of nuclear magnetic moments and electric quadrupole moments of short-lived nuclei far off stability with on-line nuclear orientation techniques. The main emphasis is put on the following items:

Quark deconfinement in nuclei: A review of experimental tests based on nuclear magnetic moment measurements

The introduction very briefly outlines the basic idea and experimental evidence to suggest that quarks may behave differently in nuclei and in indididual nucleons, with possible consequences for the calculation of nuclear magnetic dipole moments. After description of a calculation of moments made using the extreme model of total quark deconfinement (the MIT bag model) attention is focussed on experimental tests and the state of current evidence for more partial quark deconfinement. The arguments of Yamazaki which give an experimental basis for distinguishing quark deconfinement effects from, specifically, effects caused by pion echange currents, are given in more detail. The reasons underlying choice of nuclei in which meaningful tests may be possible are given. Early claims by Karl et al. to have demonstrated the existence of quark deconfinement in mass 3 nuclei are discussed. The current status of evidence for deconfinement based on orbital gfactor measurements in heavier nuclei is also summarised. Finally some examples are given of possible experiments using recently developed on-line facilities which may provide further tests of these ideas.

Direct measurement of nuclear magnetic moments of radium isotopes.

The nuclear magnetic moments of $^{213}\mathrm{Ra}$ and $^{225}\mathrm{Ra}$ have been measured at ISOLDE (isotope separator at the CERN synchrocyclotron) by observation of the Larmor precession of optically pumped atoms in a fast beam. The results ${\ensuremath{\mu}}_{I}$(${}^{213}$Ra)=0.6133(18)${\ensuremath{\mu}}_{N}$ and ${\ensuremath{\mu}}_{1}$${(\mathrm{}}^{225}$Ra)= -0.7338(15)${\ensuremath{\mu}}_{N}$ provide an accurate test of ab initio and semiempirical calculations from optical hyperfine structures in Ra i and Ra ii. .AE

Measurements of nuclear magnetic moments by transient field techniques

The intense transient magnetic fields have been applied tog-factor measurements of short-lived nuclear states. Significant data for discrete collective high-spin states in158Dy and in the actinides232Th and238U can be understood by the rotational alignment of valent neutrons and protons, respectively. Measurements on excited states of the self-conjugate nuclei20Ne and24Mg are discussed. The controversial smallg-factor of the20Ne(4+) state is particularly exciting since it contradicts all present theories.

The use of atomic beam and optical methods in the study of fundamental symmetries

We review the status of experimental tests of time reversal invariance in nuclear beta decay and discuss narrow resonance NMR techniques which are suitable for precise measurements of nuclear magnetic moments and searches for nuclear electric dipole moments.

The understanding of nuclear structure through M�ssbauer experiments

Mossbauer's discovery vitalized the study of hyperfine interactions on nuclear states. The technique has been used to measure the electromagnetic moments of scores of nuclear levels and the results, especially on rotational states, have been important to our understanding of nuclear structure. Equally signicant for nuclear physics has been the deep insight which Mossbauer studies have given us of the hyperfine interaction itself; using that knowledge, and a variety of techniques, the measurements of nuclear magnetic moments are now reliable and routine.

Measurement of nuclear magnetic moments and the tilted-multifoil interaction

The measurement of nuclear magnetic moments using the oriented electronic configurations produced by the surface interaction with several polarizing foils is described. In the limit of large number of foils, the measured effect resembles a precession of the angular correlation of decay $\ensuremath{\gamma}$ rays around a fixed external field providing important advantages over earlier single-foil measurements. The increase in the measured effects and the improved sensitivity of the present technique, are demonstrated using the Coulomb-excited ${2}_{1}^{+}$ levels in $^{110}\mathrm{Pd}$ and $^{150}\mathrm{Sm}$. MS code no. CB2026 1977NUCLEAR REACTIONS $^{110}\mathrm{Pd}$($^{32}\mathrm{S}$, $^{32}\mathrm{S}$')$^{110}\mathrm{Pd}$(${2}_{1}^{+}$), $^{150}\mathrm{Sm}$($^{32}\mathrm{S}$, $^{32}\mathrm{S}$')$^{150}\mathrm{Sm}$(${2}_{1}^{+}$) ${E}_{s}\ensuremath{\approx}90\ensuremath{-}120$ MeV, enriched targets; measured $W(\ensuremath{\theta},H,T)$ in a plunger tilted-multifoil assembly; technique for measurements of nuclear magnetic moments.

New techniques for magnetic moment measurements of short-lived excited states

The hyperfine interactions between fast ions moving through a magnetized medium and their electronic environment lead to very large magnetic fields at the nucleus. These fields have been exploited in the measurement of magnetic moments of very short-lived excited nuclear states. The present understanding of the origin and dynamic behavior of these fields is reviewed. The techniques used for the determination of magnetic moments are described and examples displaying the scope and limitations of the technique are presented. Strong directional hyperfine interactions are also manifested as fast ions exit into vacuum from foils tilted with respect to the beam. These phenomena have also been applied successfully to the measurement of nuclear magnetic moments and are briefly discussed.

Nuclear moments and moment ratios as determined by Mössbauer spectroscopy

Values are given for Mössbauer effect measurements of nuclear magnetic moments, spectroscopic quadrupole moments, ratios of moments between low lying excited states and the ground state of the same isotope, and ratios of moments between states of different isotopes. Adopted values for moments, obtained by direct selection of selection of specific results or by an averaging process, are presented. The literature has been covered through December, 1974.

Measurement of nuclear magnetic moments by perturbed polarization-directional angular correlation

Perturbed polarization-directional angular correlation by external magnetic field proves to be useful to determine the magnetic moment of a nuclear excited state when anisotropy in the conventional directional-directional angular correlation is very small. This method has been applied to the 70 keV52+ level in 177Ta and the magnetic moment of this level has been found to be +(4.7±0.5)μN.

Measurement of Nuclear Magnetic Moments in Atomic Beams

THE purpose of this communication is to describe a magnetic resonance experiment which we have performed with three radio-frequency loops situated in the C field of an atomic-beam apparatus, and to propose an application. Apart from the three loops, we used a conventional ‘flop-in’ arrangement with short A and B magnets. The method to be described allowed the measurement in a short apparatus of transitions for which Δm J = 0; such lines are usually unobservable except in machines with long A and B magnets1. The atomic beam was potassium-39, for which J = ½ in the ground-level and I = 3/2.

Magnetic Shielding of Nuclei in Molecules by a Variational Method

The accurate measurement of nuclear magnetic moments requires a calculation of the magnetic field at the nucleus arising from the orbital motions of the electrons in the external magnetic field. In this note we outline a solution of the ``magnetic shielding effect,'' using the quantum-mechanical variation principle. Since all results are in terms of ground-state wave functions, such an approach may facilitate a purely theoretical evaluation of shielding constants. As a variation function we take a function of the type suggested by Hylleraas and Hassé and applied successfully to calculation of polarizabilities. Previously, Ramsey used a second-order perturbation method to calculate the magnetic shielding. His results are difficult to apply since the wave functions of excited electronic states of molecules are seldom available.

Magnetic Moments of Deuterium-2, Lithium-7 and Fluorine-19

THE exceptionally small natural line-widths obtainable with the magnetic resonance absorption method1,2 or nuclear induction method3,4 makes these methods suitable for precision measurements of nuclear magnetic moments. We have constructed an apparatus for this purpose, and have paid special attention to the problem of getting a magnetic field which fulfils the rather extreme requirements of field homogeneity. In this case it was also important that the homogeneity was of such an extension that two different probes could be investigated at the same time on two different places in the field. The pole-pieces of the magnet were 30 cm. in diameter, separated by spacers 4·2 cm. apart. Both the pole-pieces and the spacers were polished optically flat, so that the air gap was the same within 1 µ everywhere.