Long-lived isomers in 190Ir

Long-lived isomeric states in 190Ir have been investigated with the 192Os(p,3n) 190Ir and 192Os(d,4n) 190Ir reactions using beams of 18–31 MeV protons and 27.8 MeV deuterons, respectively. A series of measurements, including excitation functions, half lives, e−γ coincidences and e−e− coincidences, was performed. Five new transitions were observed, and the results of e−γ and e−e− coincidences indicate that these transitions are fed by the 148.7 keV M4 transition that depopulates the 11− isomer. The previous decay scheme is shown to be incorrect, and the results allow the ground state parity and mass excess to be determined.