Probing the low-lying level structure of ⁹⁴Zr through β^- decay

There exists a variety of nuclear structure phenomena within the chain of Zr isotopes in the low-excitation regime. While the ground state of ⁹⁴Zr is spherical in nature, the occurrence of low-lying collective structure has also been observed. The excitation of protons across the Z = 40 sub-shell closure appears to playa dominant role for this collective structure in ⁹⁴Zr. With the goal of looking for possible competition between proton and neutron excitations in ⁹⁴Zr, an experiment was carried out at the TRIUMF-ISAC radioactive beam facility. The low-lying states of ⁹⁴Zr were populated from the β^- decay of ⁹⁴Y. The 8π spectrometer was composed of 20 Compton-suppressed HPGe detectors; details of the experimental setup can be found in earlier literature. Combining the singles and coincidence data, a comprehensive level scheme of ⁹⁴Zr has been constructed up to E_x ∼ 4.8 MeV, which is very close to the Q_β^- value 4.918 MeV. With the revised level lifetimes and the newly found decay branches from the present investigation, the levels could be categorized in terms of proton and neutron excitations. Detailed results obtained from the analysis of the acquired data will be presented