C. E. Doran

Gyromagnetic ratios of excited states in 150Sm and 152Sm

Abstract The gyromagnetic ratios of the 2 1 + , 4 1 + , 6 1 + , 2 2 + , and 2 3 + states in 150 Sm and the 2 1 + , 4 1 + , 6 1 + , 8 1 + , 10 1 + , 2 2 + , and 2 3 + levels in 152 Sm have been measured using the transient field perturbed γ-ray angular correlation technique. States of interest were populated by multiple Coulomb excitation using 150- and 220-MeV 58 Ni beams. The present results display no significant deviation from constancy of the g -factors of all levels investigated in either isotope separately or of corresponding states in 150,152 Sm. These findings are compared with available prior measurements and assessed in terms of applicable theoretical model calculations.

Disparity of measured gyromagnetic ratios of ground- and excited-band states in184W

Gyromagnetic ratios of levels in the ground-band and of the 22+ state in184W were measured by means of the transient magnetic field perturbedγ-ray angular distribution technique. The levels of interest were Coulomb excited by beams of 220-MeV58Ni and63Cu ions. The results show theg-factor of the 22+ state to be approximately half the effectively constant value found for the ground-band levels. This disparity is compared with those previously obtained for the corresponding states in188–192Os and186W; these are discussed in the context of the interacting boson model.

Gyromagnetic ratios of excited states in186W

The gyromagnetic ratios of the 41+, 61+, and 22+ states in186W were measured relative to that of the 21+ level by means of the transient field implantation perturbedγ-ray angular distribution technique. The nuclei in the states of interest were Coulomb excited using a beam of 220-MeV63Cu projectiles and recoiled swiftly through a thin, polarized Fe foil. The present measurements yielded ratiosg(41+)/g(21+)=1.04±0.07,g(61+)/g(21+)=1.03 ±0.20 andg(22+)/g(21+)=0.63±0.13. The sizable disparity between the measuredg-factors of the ground- and excited-band is examined within the context of the interacting boson approximation model.

Transient fields for W ions traversing Fe hosts and for Os ions traversing Fe and Ni hosts

Transient field strengths were measured for184, 186W ions traversing thin, magnetized Fe foils with velocities in the range 1.8 ≲ υ/υ0 ≲ 5.7 (υ0 = Bohr velocity) and for188, 190, 192Os ions traversing polarized Ni hosts with average velocities 〈υ/υ0〉 ∼ 4. The present measured transient field strengths, together with previously measured results for W, Os ions, are compared with transient field strength parametrizations, and discussed in terms of microscopic models of the transient field.

Measured gyromagnetic ratios and the low-excitation spectroscopy of 197Au

Abstract Transient-field precessions were measured for levels in 197 Au and 182,184,186 W as their ions simultaneously traversed polarized Gd hosts. Gyromagnetic ratios were inferred for the positiveparity levels between, and including, the lowest 5 2 + and 11 2 + states in 197 Au. Lifetimes of several levels were determined using the Doppler-broadened lineshape technique, and multipole mixing ratios of a number of transitions were deduced from measured particle-γ-ray angular correlations. The measured static and dynamic electromagnetic moments are compared with the predictions of the weak-coupling core-excitation model and with those of the interacting boson-fermion model (IBFM), including its Spin(6) supersymmetry limit.

Transient-field strength measurements for52Cr traversing Fe hosts at high velocity and polarization transfer mechanisms

Transient-field strengths were measured for52Cr ions traversing polarized Fe hosts at velocities up to 12υ0 (12υ0 =c/137 = Bohr velocity). The results are compared with predictions of various transient-field parametrizations and discussed in terms of possible mechanisms by which polarization might be transferred from the Fe host to inner vacancies of the moving Cr ions. Theg-factor of the first 2+ state of52Cr was also measured by the transient-field technique and found to be in accord with shell model calculations.

Measured gyromagnetic ratios of individual excited states in the ground- and gamma-bands of166Er

The gyromagnetic ratios of levels up to the 101+ in the ground-state band and of the 22+ state in theγ-band of166Er were simultaneously determined experimentally by means of the thin-foil, perturbedγ-ray angular distribution technique utilizing the transient hyperfine field manifest at nuclei of Er ions rapidly traversing polarized Fe. Beams of 220- and 160-MeV58Ni projectiles were used to Coulomb excite the levels of interest. The present results are compared with the spin-dependencies ofg-factors of levels in the ground-band predicted by recent cranked Hartree-Fock-Bogoliubov calculations and with interacting boson model expectations which includeg-boson effects.

Systematics of gyromagnetic ratios of the 2+-1- states in even Ge isotopes

The relative gyromagnetic ratios of the 2t states in 70,72,74,76Ge were measured simultaneously by me ns of the thin-foil, perturbed y-r yngular distribution technique utilising the transient hyperfine field manifest t nuclei of Ge ions rapidly traversing polarised Fe. The states of interest were Coulomb excited using 75-MeV 34S projectiles incident upon natural element l Ge t rget. The present results re comp red with previously reported measurements and collective model expectations.

Gyromagnetic ratios of excited states in 103Rh

Abstract Transient-field precessions were measured simultaneously for levels in 103 Rh and the first 2 + states in even Pd isotopes as their ions traversed polarized Fe hosts, Gyromagnetic ratios were inferred for the negative-parity levels in 103 Rh up to an excitation energy of ∼1 MeV. E2/M1 multipolarity mixing ratios were determined and/or confirmed for some transitions from measured unperturbed particle-γ-ray angular correlations. The measured static and dynamic electromagnetic moments are compared with present interacting boson-fermion model (IBFM) calculations which reproduce the main features of the spectrum of both the positive- and negative-parity levels in 103 Rh below an excitation energy of ∼1 MeV.

Disparity in transient field characteristics for Au ions traversing Fe and Gd hosts through measurements ofg-factors in197Au

Transient field precessions were measured for levels in the nuclides of182,184,186W and197Au as their ions simultaneously traversed polarized Fe and Gd hosts. Consistent sets of gyromagnetic ratios were inferred for the lowest 5/2+ and 7/2+ states in197Au using these two ferromagnetic host media, provided that (i) the transient field for Au ions in Gd is calibrated using the W in Gd precessions (simultaneously measured) and, (ii) the transient field for Au in Fe is calibrated using the field strength and velocity dependence for Pt in Fe (previously measured). The presentg-factor results are: g(5/21+;197Au)=0.296±0.023, g(7/21+;197Au)=0.241±0.021, and g(5/21+;197Au)=1.2±0.2.