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g-Factors Near the First Backbend in 82Sr and 84Sr

  • A. I. Kucharska
  • J. Billowes
  • C. J. Lister
Conference paper
Part of the Research Reports in Physics book series (RESREPORTS)

Abstract

The gyromagnetic ratio is an important quantity in spectroscopic studies of deformed nuclei because its value is sensitive to proton or neutron quasiparticle admixtures in the nuclear wave-function. When the lifetimes of these states are only a few picoseconds the transient field (TF) technique seems to provide the best means of measuring their g-factors. In this method the magnetic field is experienced by the nucleus of an ion only as it moves with high velocity (≥ 0.01c) through a ferromagnet such as iron or gadolinium. Although the very short stopping times of ions in solids (∼ 1 ps) limits the duration of the field, measurable nuclear precessions of typically ΔΦ≃2° are produced which are directly proportional to the nuclear g-factor:
$$\vartriangle \Phi = - \frac{{g{\mu _N}}}{\hbar }\int\limits_{{t_i}}^{{t_o}} {{B_{TF(\upsilon ){e^{ - t/\tau }}dt}}}$$
(1)

The field strength B TF depends on the instantaneous velocity of the ion and is therefore a function of time. The limits t i and t o are the entry and exit times of the ferromagnetic foil and τ is the mean lifetime of the nuclear state. The application of the TF technique to states near the backbend of deformed nuclei has been hampered by the relatively long times taken to populate these levels by the γ-ray cascade following heavy-ion reactions; in the rare-earth and mass-130 regions the side-feeding times to discrete yrast states are comparable to the stopping time of the ions and at which time the transient field disappears. Such difficulties seem to be greatly reduced in the mass-80 region; a number of experiments using recoil-distance and Doppler-shift attenuation methods [1,2] find rather fast side-feeding times of the order of 0.1 ps to states near the first backbend (E x ≈ 4 MeV), particularly when the excited nucleus is formed at low spin. It should therefore be possible to measure g-factors of these states in a TF experiment. In the present work we have applied the TF technique to states in the transitional nuclei 82Sr and 84Sr which exhibit backbending around spin 8+ due to alignment of either proton or neutron g 9/2 quasiparticles.

Keywords

Double Ratio Iron Foil Negative Parity State Transient Field Nuclear Precession 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Berlin Heidelberg 1988

Authors and Affiliations

  • A. I. Kucharska
    • 1
  • J. Billowes
    • 2
  • C. J. Lister
    • 2
  1. 1.Nuclear Physics LaboratoryOxford UniversityOxfordUK
  2. 2.Department of Physics, Schuster LaboratoryManchester UniversityManchesterUK

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