Experimental study of the low-lying structure of Zr94 with the (n,n'γ) reaction

The low-lying structure of 4094Zr was studied with the (n,n'γ) reaction, and a level scheme was established based on excitation function and γγ coincidence measurements. Branching ratios, multipole mixing ratios, and spin assignments were determined from angular distribution measurements. Lifetimes of levels up to 3.4 MeV were measured by the Doppler-shift attenuation method, and for many transitions the reduced transition probabilities were determined. In addition to the anomalous 22+ state, which has a larger B(E2;22+→01+) value than the B(E2;21+→01+), the experimental results revealed interesting and unusual properties of the low-lying states in Zr94. In a simple interpretation, the excited states are classified in two distinct categories, i.e., those populating the 22+ state and those decaying to the 21+ state.