Low-spin excitations in 97Zr

The main goal of this work is the determination of spins and parities of excited states in Zr-97, among others the 2264.3-keV level, which had previously been tentatively reported as the 11/2(-) excitation corresponding to the h(11/2) neutron orbital. Low-spin excited states in Zr-97 were populated via the cold-neutron capture reaction. The gamma rays emitted following the reaction were measured using the highly efficient array of high-purity germanium detectors, EXILL, at the Institut-Laue-Langevin (ILL), Grenoble. The primary gamma rays deexciting the capture state in( 97)Zr were identified for the first time. The new, precise neutron binding energy in Zr-97 of 5569.15(4) keV differs significantly from the value reported in the literature. The previously reported level scheme has been amended by several new low-spin levels. The (n, gamma) data were complemented by a measurement of the beta(-) decay of Y-97 at the Lohengrin fission-fragment separator of the ILL, and the observation of the beta(-) decay of Y-97 populated in neutron-induced fission of U-235 and measured using the EXILL Ge array. The combined data allowed unique spin-parity assignments for many levels in Zr-97. The 2264.3-keV level, with a new spin-parity assignment of 9/2(+), may correspond to the vg(9)(/2) extruder orbital.