Neutron-proton multiplets in the odd-odd nucleus $^{90}_{37}$Rb$_{53}$

Medium-spin excited levels in 90Rb, populated in the fission of 235U induced by neutrons, have been observed for the first time. γ radiation from fission has been measured by using the EXILL array of Ge detectors at the cold-neutron-beam facility PF1B of the Institut Laue–Langevin, Grenoble.