The nuclei ${}^{163,164}\mathrm{Dy}$ have been investigated using the Oslo method on data from the pickup reaction ${}^{164}\mathrm{Dy}$(${}^3\mathrm{He}$,$\alpha \gamma$)${}^{163}\mathrm{Dy}$ and the inelastic scattering ${}^{164}\mathrm{Dy}$(${}^3\mathrm{He}$,${}^3\mathrm{He}$${}^{\prime }\gamma$)${}^{164}\mathrm{Dy}$, respectively. The radiative strength functions for both nuclei have been extracted, and a small resonance centered around $E_{\gamma }\approx 3$ MeV is observed in both cases. The parameters of this so-called pygmy $M1$ resonance (the scissors mode) are compared with previous results on ${}^{160,161,162}\mathrm{Dy}$ using the Oslo method, and with data on ${}^{163}\mathrm{Dy}$ measured by the Prague group using the two-step cascade method. In particular, the integrated reduced transition probability $B(M1\uparrow )$ of the pygmy resonance is compared with neighboring dysprosium isotopes. We also observe an enhanced strength in the region above $E_{\gamma }\approx 5$ MeV in ${}^{164}\mathrm{Dy}$. Possible origins of this feature are discussed.

• Received 3 September 2009

DOI:https://doi.org/10.1103/PhysRevC.81.024325