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Gamma-ray strength function and pygmy resonance in rare earth nuclei

A. Voinov·M. Guttormsen·E. Melby·J. Rekstad·A. Schiller·S. Siem
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Abstract

The gamma-ray strength function for gamma energies in the 1-7 MeV region has been measured for 161,162-Dy and 171,172-Yb using the (3-He,alpha gamma) reaction. Various models are tested against the observed gamma-ray strength functions. The best description is based on the Kadmenskii, Markushev and Furman E1 model with constant temperature and the Lorentzian M1 model. A gamma-ray bump observed at E_gamma=3 MeV is interpreted as the so-called pygmy resonance, which has also been observed previously in (n,gamma) experiments. The parameters for this resonance have been determined and compared to the available systematics.

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A. Voinov, M. Guttormsen, E. Melby, J. Rekstad, A. Schiller, S. Siem. 2000-09-26. Gamma-ray strength function and pygmy resonance in rare earth nuclei. https://doi.org/10.1103/physrevc.63.044313

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