Study of high spin states in 90Nb and 91Nb

The high spin states of 90Nb and 91Nb have been populated via reaction 76Ge(19F, xn) at beam energy of 80 MeV. The de-exciting γ-rays have been measured with in-beam γ-ray spectroscopy method. After γ-γ coincidence analysis, the new level scheme of 90Nb and 91Nb was established. Based on the semi-empirical shell model calculations, the configurations of the levels have been suggested, in addition, the spins and parities of the new levels have been assigned according to the experimental DCO values and to the systematic comparison with the neighboring nuclei.