First-excited state g  factors in the stable, even Ge and Se isotopes

Abstract

Transient-field g-factor measurements in inverse kinematics were performed for the first-excited states of the stable, even isotopes of Ge and Se. The g factors of 74 Ge and 74 Se were measured simultaneously using a cocktail beam, which eliminates most possible sources of systematic error in a relative g-factor measurement. The results are g( 74 Se)/g( 74 Ge) = 1.34 (7), g( 70 Ge)/g( 74 Ge) = 1.16(15), g( 72 Ge)/g( 74 Ge) = 0.92(13), g( 76 Ge)/g( 74 Ge) = 0.88(5), g( 76 Se)/g( 74 Se) = 0.96 (7), g( 78 Se)/g( 74 Se) = 0.82(5), g( 80 Se)/g( 74 Se) = 0.99(7) and g( 82 Se)/g( 74 Se) = 1.19(6). The measured g-factor ratios are in agreement with ratios from previous measurements, despite considerable variation in previous reported absolute values. The absolute values of the g factors remain uncertain, however the Rutgers parametrization was used to set the transient-field strength and then compare the experimental g factors with shell-model calculations based on the JUN45 and jj44b interactions. Modest agreement was found between experiment and theory for both interactions. The shell model calculations indicate that the g(2 + 1 ) values and trends are determined largely by the balance of the spin carried by orbital motion of the protons.

Nuclear DFT analysis of electromagnetic moments in odd near doubly magic nuclei

“…to test our description of microscopic properties such as those of valence nucleons [3][4][5][6][7][8] and the role of nuclear electroweak currents [9,10]. Although great progress was achieved in the description of electromagnetic properties of light nuclei [10] and experimental trends in certain isotopic chains, a unified and consistent description of nuclear electromagnetic properties remains an open challenge for nuclear theory.…”

The Heavy Ion Accelerator Facility: Research Achievements and Aspirations

“…The Hyperfine Spectrometer [18] allows the application of a magnetic field to a target that can be cooled to 4 K. Perturbed particle-angular correlations are measured to determine nuclear moments or study atomic physics, ion-solid interactions, or materials science via hyperfine interactions methods. Research over the last decade has included a strong focus on methodology and technique development for g-factor measurements on neutron-rich nuclei produced at international radioactive beam facilities, by the transient-field and recoil in vacuum methods [19][20][21][22][23][24][25]. Current work, also tied to experiments at international radioactive beam facilities, has explored the nature of weakly collective nuclei [26], and the emergence of nuclear collectivity near doubly magic 132 Sn, through g-factor and B(E2) measurements, and comparisons with detailed shell model calculations [27][28][29][30].…”

“…More recently, pair spectroscopy has been used to study E0 transitions in relatively low-Z nuclei. Examples are 0 + → 0 + transitions in the N = Z nuclei 24 Mg and 40 Ca, and a systematic study of E0 transition strengths near N = 28 and Z = 28 that is finding that strong E0 transitions occur only in the semimagic isotopes [39][40][41].…”