Alpha-decay spectroscopy of $$^{257}$$ 257 Rf

The decay properties of states in $$^{257}$$ Rf have been investigated with the detector array GABRIELA at the FLNR, Dubna. The electromagnetic decay of a new excited state in $$^{253}$$ No has been observed. The state lies 750 keV above the ground state and is favourably populated in the alpha decay from a low-lying isomeric state in $$^{257}$$ Rf. It decays to the 9/2 $$^-$$ ground state by an M1 transition and is assigned the 11/2 $$^-$$ [725] Nilsson configuration. The presence of this state suggests a possible reinterpretation of the decay of the high-K isomer in $$^{253}$$ No. Due to the favoured nature of the $$\alpha $$ -decay the 11/2 $$^-$$ [725] Nilsson configuration is also assigned to the first excited state of $$^{257}$$ Rf, lying at 74 keV.