Transitional Nuclei. II. Properties of the Levels in 152 Sm and 152 Gd from the Decay of the 152 Eu m,g Isomeric Pair
1971; NRC Research Press; Volume: 49; Issue: 19 Linguagem: Inglês
10.1139/p71-295
ISSN1208-6045
AutoresJ. Barrette, M. Barrette, A. Boutard, Guillaume Lamoureux, S. Monaro, S. Markiza,
Tópico(s)Nuclear Physics and Applications
ResumoThe γ rays emitted in the decay of the 152 Eu m,g isomeric pair have been studied with the use of high-efficiency, high-resolution, solid-state detectors. These measurements together with Ge(Li)–Ge(Li) coincidence experiments revealed the existence of several new gamma transitions never previously reported. In all, 93 and 30 γ rays were observed in the decay of 152 Eu g and 152 Eu m , respectively. Calculations of the β- and γ-band mixing into the ground-state rotational band and into each other were carried out. These calculations showed that this mixing is insufficient in explaining the B(E2) ratios from the members of both the β and γ band. In addition, the very likely existence of a K π = 2 − band in 152 Sm, with levels at 1649.90 (2 − ) and 1757.0 keV (3 − ), has been unveiled in these measurements. Furthermore, the existence of a new K π = 0 − octupole rotational band (levels at 1680.58 (1 − ) and 1730.3 (3 − )) built on the β-vibrational band and the presence of a collective K π = 2 + vibrational state at 1769.1 keV, which most probably can be described as a coupled (βγ) two phonon state, are also proposed. Moreover, a new level at 1292.75 keV has been established through coincidence experiments in 152 Sm. This level may be considered either as the 2 + member of a second β-vibrational band or, more likely, can be described as a truly spherical state in light of recent experiments involving (t,p) and (p,t) transfer reactions to levels of 152 Sm. Finally, a qualitative analysis of the level structure of 152 Gd, as well as 150 Sm, seems to show that these two nuclei display a more rotational nature than a spherical (or vibrational) one as previously suggested.
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