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This paper reports NMR measurements of the magnetic dipole moments of two high-K isomers, the 37/2-, 51.4 m, 2740 keV state in Hf177 and the 8-, 5.5 h, 1142 keV state in Hf180 by the method of on-line nuclear orientation. Also included are results on the angular distributions of γ transitions in the decay of the Hf177 isotope. These yield high precision E2/M1 multipole mixing ratios for transitions in bands built on the 23/2+, 1.1 s, isomer at 1315 keV and on the 9/2+, 0.663 ns, isomer at 321 keV. The new results are discussed in the light of the recently reported finding of systematic dependence of the behavior of the gR parameter upon the quasiproton and quasineutron make up of high-K isomeric states in this region. © 2014 American Physical Society.

Using new techniques developed for measuring angular correlations with large detector arrays, the g factors of 2+ states in Xe140,142 are measured for the first time by the method of correlation attenuation in randomly oriented magnetic fields. g factors in Ba146 and Ce146,148 are measured to establish the method by comparison with previous values. The results are discussed in terms of IBM-2 and rotation-vibration models. © 2009 The American Physical Society.

This paper reports measurements made using the technique of online nuclear orientation which reexamine the γ decay of isomeric 180Hfm and specifically the 501 keV 8 - 6+ transition. The irregular admixture of E2 to M2/E3 multipolarity in this transition, deduced from the forward-backward asymmetry of its angular distribution, has for decades stood as the prime evidence for parity mixing in nuclear states. The experiment, based on ion implantation of the newly developed mass-separated 180Hfm beam at the CERN online isotope mass separator (ISOLDE) facility into an iron foil maintained at millikelvin temperatures, produces higher degrees of polarization than were achieved in previous studies of this system. The value found for the E2/M2 mixing ratio, ε=-0.0324(16)(19), is in close agreement with the previous published average value ε=-0.030(2), in full confirmation of the presence of the irregular E2 admixture in the 501 keV transition. The temperature dependence of the forward-backward asymmetry has been measured over a more extended range of nuclear polarization than previously possible, giving further evidence for parity mixing of the 8- and 8+ levels and the deduced E2/M2 mixing ratio. © 2007 The American Physical Society.

We report a programme of novel experiments involving direct proton emission and beta-delayed proton and neutron emission for exotic nuclei oriented at low temperatures. Full modelling of the quantum tunneling and angular distribution has been made for the first time for these processes. Their study has application in many fields of natural science. The study of barrier effects involving angular momentum and non-spherical deformation can be approached more directly via single-particle emission than via alpha decay, which suffers from complications relating to preformation of the alpha particle. Using the new formalism, predictions are presented for angular distributions of beta-delayed neutrons from oriented I-137 and of direct proton emission from oriented Tm-147.

The multipole mixing ratios of ΔI=1 transitions between levels in rotational bands built on single-particle states in odd neutron nuclei are dependent on the configurations of the states. In particular, the mixing ratio can be used to distinguish between several possible single-particle configurations if interpreted with the particle-axial-rotor model. This work features the first determination of the ground-state configurations of Ru109,111. The single-particle structures of the ground states of Zr101 and Mo103,105,107 as well as excited states in Mo103,107 are also investigated, with a new result found in Mo107. © 2009 The American Physical Society.

Precision asteroseismic observations with the Kepler and CoRot satellites enable the internal structure and evolution of pulsating stars to be more exhaustively studied than has hitherto been possible. It is particularly important to study the evolutionary links between white dwarfs and subdwarf-B stars with stars considered to have been their progenitors, those on the Red Giant and Asymptotic Giant Branches. Though observations present challenges for existing stellar evolution and pulsation models, and the data (atomic, molecular and nuclear) on which they are based, excellent prospects for development are identified which will in turn facilitate studies of the Galaxy and extra-solar planets. © 2013 Owned by the authors, published by EDP Sciences.

New results on the applied field dependence of the NMR of Se-75 implanted in pure iron and oriented at millikelvin temperatures are reported. They yield the magnetic hyperfine field acting on Se nuclei present as dilute impurities in the iron matrix and the magnetic dipole moment of the 5/2(+) ground state of Se-75 with significantly improved precision. The results are B-hf(SeFe) = +67.9(10) T and \mu\(Se-75) = 0.683(10) mu (N). The improved value of the hyperfine field, with data from [2], gives the magnetic dipole moment of the 9/2(+) ground state of Se-73 as \mu\ = 0.892(13) mu (N).

Statistical model of beta-delayed proton emission is briefly reviewed. Theory of angular distribution of beta-delayed proton emission from nuclear states oriented at low temperatures is discussed and the design of the first trial experiment using Cs-118 oriented at low temperature at the ISOLDE/NICOLE facility at CERN is described.

Recent on-line nuclear orientation measurements of odd-A nuclear magnetic dipole moments of odd-A Sb, Te and I isotopes by the method of NMR on oriented nuclei mean that we now have complete series of odd-A moments up to, and including, those closest to the double shell closure at Sn-132. In this paper we consider the systematic changes in the measured moments as a function of proton number for the isotonic sequence Sb-133 [g(7/2+)](1) -La-139 [g(7/2+)](7) and as a function of neutron number for the isotopic sequences Sb125-133 and I127-135 and their interpretation using collective and shell model approaches.

Excited states in the odd-AGa71,73,75,77 nuclei have been populated in deep-inelastic reactions of a Ge76 beam at 530 MeV with a thick U238 target. High-spin sequences built upon the 9/2+, 5/2-, and 3/2- states were identified in all four isotopes. A comparison of the observed structures with the yrast positive-parity states in the neighboring even-even Zn cores indicates that the newly identified levels may be regarded as arising from the relatively weak coupling of the odd proton to the core states. However, significant contributions from broken pairs are expected to be present in this region of excitation energy. The present data set also provides clarification of previously reported decay paths of the low-energy levels in Ga71,73,75,77. © 2009 The American Physical Society.

On-line low temperature nuclear orientation (OLNO) experiments have been performed on the odd-A Te isotopes 131Te and 133Te using the technique of nuclear magnetic resonance on oriented nuclei (NMR/ON). The magnetic moments of the isomeric 11/2- states have been measured extending the known data on these states in the Te isotopes up to the neutron shell closure at N = 82. The contribution to the 11/2- magnetic moment in 133Te due to core polarisation is calculated using an RPA shell model as well as corrections to the magnetic dipole operator caused by mesonic exchange currents. The neutron number dependence of the magnetic moments of the 11/2- isomers in heavy Te isotopes is discussed in terms of particle-core coupling model (PCM) calculations. © 1998 Elsevier Science B.V.

On-line low temperature nuclear orientation (OLNO) experiments have been performed on the isotope 135I using the technique of nuclear magnetic resonance on oriented nuclei (NMR/ON). The magnetic moment of the 7/2+ ground state has been measured to be μ(7/2+135I) = 2.940(2)μN, thereby extending the known data on these states in odd-A I isotopes up to the neutron shell closure at N = 82. Shell-model calculations have been performed for the magnetic moments of 7/2+ states in the N = 82 isotones using free-nucleon and effective g-factors. The effective g-factors are obtained from a perturbation calculation that includes corrections for core polarisation and meson-exchange currents. The proton number dependence of the magnetic moments in the sequence of N = 82 isotones 133Sb-139La is discussed in terms of blocking of the Og9/2 to Og7/2 core polarisation with increasing Og7/2 occupancy. Systematics of all measured 7/2+ odd-proton moments for 74 ≤ N ≤ 82 are reviewed. © 1998 Elsevier Science B.V.

The existence of two decaying isomers in 184Au was confirmed through direct observation of the variation of decay rates with time. The ordering of the low- and high-spin isomers was verified by the decay studies. The isomers are identified as a low-spin (probably 2+) state at an energy of 69 keV with a half-life of 48±1 sec and a high-spin (probably 5+) ground state with a half-life of 21±1 sec.

The level scheme of odd-Z neutron-rich 141Cs (Z=55, N=86) was extended and expanded and that of 144Cs (N=89) was identified for the first time by means of γ-γ-γ coincidence measurements of prompt γ rays in the spontaneous fission of 252Cf with Gammasphere. Spin/parity was assigned to the levels based on angular correlations and level systematics in 141,143Cs. Parity doublets characteristic of both simplex quantum number s=+i and s=-i were proposed in 141Cs. The tests by using rotational frequency ratio ω-(I)/ω+(I) imply octupole vibrations in 141Cs and 143Cs. B(E1)/B(E2) values and electric dipole moments D0 were calculated for 141Cs, and re-determined for 143Cs. It was found that B(E1)/B(E2) values of 141Cs are simplex-dependent and the average value is one order of magnitude larger than that of 143Cs, and the deduced dipole moment D0 of 141Cs is considerably larger than that of 143Cs, and comparable to the N=86 isotone 142Ba. For 144Cs the yrast sequence looks like a well-deformed rotational band, but no octupole band structure was identified in this nucleus. The overall variations of D0 in 141,143,144Cs exhibit a pronounced drop of dipole moment with increasing neutron number in this odd-Z isotopic chain, which may be analogous in nature to the quenching of D0 observed in even-even 146Ba (Z=56, N=90) and 224Ra (Z=88, N=136), and to the drop of D0 in the odd-Z neutron-rich 147La (Z=57, N=90) reported by our collaboration. © 2010.

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)μN and +1.61(5)μN, 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) μN. ©2011 American Physical Society.

Our article neglected to cite the work of Coraggio, where a low-momentum NN potential derived from the CD-Bonn NN potential was used to construct an effective interaction for a Sn132 core. This interaction was used to compare with the experimental energy level spectra of Sb132 and other nearby nuclei. © 2005 The American Physical Society.

Following Coulomb excitation of the radioactive ion beam (RIB) 132Te at HRIBF we report the first use of the recoil-in-vacuum (RIV) method to determine the g factor of the 2(+)(1) state: g(973.9 keV 2(+) 132Te) = (+)0.35(5). The advantages offered by the RIV method in the context of RIBs and modern detector arrays are discussed.

This paper reports NMR measurements of the magnetic dipole moments of two high-K isomers, the 37/2-, 51.4 m, 2740 keV state in Hf177 and the 8-, 5.5 h, 1142 keV state in Hf180 by the method of on-line nuclear orientation. Also included are results on the angular distributions of γ transitions in the decay of the Hf177 isotope. These yield high precision E2/M1 multipole mixing ratios for transitions in bands built on the 23/2+, 1.1 s, isomer at 1315 keV and on the 9/2+, 0.663 ns, isomer at 321 keV. The new results are discussed in the light of the recently reported finding of systematic dependence of the behavior of the gR parameter upon the quasiproton and quasineutron make up of high-K isomeric states in this region. © 2014 American Physical Society.

The g factor of the 15/2- state in Xe137 was measured for the first time by using a newly developed technique for measuring angular correlations with Gammasphere. Spins and parities were assigned to several levels in the N=83 isotones Te135, I136, Xe137, and Cs138. The calculated g factor in the shell-model frame is in good agreement with the measured one in the present work. Shell-model calculations also support our spin-parity assignments. © 2010 The American Physical Society.

We report the first confirmation of the predicted inversion between the π2p3/2 and π1f5/2 nuclear states in the νg9/2 midshell. This was achieved at the ISOLDE facility, by using a combination of in-source laser spectroscopy and collinear laser spectroscopy on the ground states of Cu71,73,75, which measured the nuclear spin and magnetic moments. The obtained values are μ(Cu71)=+2.2747(8)μN, μ(Cu73)=+1.7426(8)μN, and μ(Cu75)=+1.0062(13)μN corresponding to spins I=3/2 for Cu71,73 and I=5/2 for Cu75. The results are in fair agreement with large-scale shell-model calculations. © 2009 The American Physical Society.

Rotational bands in Ru-108,Ru-110,Ru-112 have been investigated by means of gamma-gamma-gamma and gamma-gamma(theta) coincidences of prompt gamma rays emitted in the spontaneous fission of Cf-252. The positive parity bands are described by different versions of IBA, where Ru-108 is best described as a gamma-soft nucleus whereas Ru-110,Ru-112 these are more like rigid triaxial rotors. New Delta I = 1 negative parity doublet bands are found. In case of Ru-110,Ru-112, these are interpreted as soft chiral vibrations. Many of the experimental findings can be explained by microscopic calculations that combine the TAC mean-field with random phase approximation but a simple geometrical explanation is not apparent. ispartof: Physics letters b vol:670 issue:4 pages:307-312 status: published

Two similar sets of odd-parity bands are observed in each of three eveneven neighbors, 108, 110, 112Ru, from a study of prompt spontaneous-fission gamma rays at Gammasphere. A careful study of the odd-parity levels of these nuclei shows evidence for the features of chiral doubling. Comparisons are made with reported other candidates for chiral doubling. © 2009 World Scientific Publishing Company.

The first fully on-line use of the angular distribution of beta emission in detection of NMR of nuclei oriented at low temperatures is reported. The magnetic moments of the single valence particle, intermediate mass, isotopes 67Ni(nup(-1)(1/2);1/2(-)) and 69Cu(pip(1)(3/2);3/2(-)) are measured to be +0.601(5) andmgr;(N) and +2.84(1) andmgr;(N), respectively, revealing only a small deviation from the neutron p(1/2) single-particle value in the former and a large deviation from the proton p(3/2) single-particle value in the latter. Quantitative interpretation is given in terms of core polarization and meson-exchange currents.