A large variety of shapes may be observed in Sr and Zr nuclei of the A = 100 region when the number of neutrons increases from N = 58 to N = 64. The lighter isotopes are rather spherical. It is also well established that three shapes co-exist in the transitional odd-A, N = 59, Sr and Zr nuclei. For N > 59, strongly deformed axially symmetric bands are observed. Recently, a new isomer of half-life 1.4(2) \mu s was observed in ⁹⁵Kr, the odd--odd ⁹⁶Rb has been reinvestigated and a new high-spin isomer observed in the even--even ⁹⁸Zr. These nuclei were studied by means of prompt \gamma -ray spectroscopy of the spontaneous fission of ²⁴⁸Cm using the EUROGAM 2 Ge array and/or measurements of \mu s isomers produced by fission of ^239,241Pu with thermal neutrons at the ILL (Grenoble). To allow spectroscopic studies of isomeric states with lifetimes around 100 ns, across a broad range of medium-heavy neutron-rich nuclei, an experiment was performed at a neutron guide of the ILL using thermal-neutron-induced fission. Fission fragments were identified using a small spectrometer consisting of a section to measure time-of-flight and an ionization chamber. Isomeric \gamma rays emitted from complementary fragments were detected in an array of Ge detectors.

PACS numbers: 21.10.Tg, 23.20.Lv, 25.85.Ec, 27.60.+j