IV. Radioactivity of neutron excess iridium isotopes

The half-lives, mass assignments and radiation characteristics of the neutron excess iridium isotopes have been determined as follows: The gamma-ray energies of 19-hour 194Ir have also been examined. The 7-second 194mIr isomer is either a 125 kev E3 transition followed by the 5·6 mev gamma-ray or possibly a 5·6mev M6, E6 or E7 transition followed by a 125 kev M1. E2 or E3 gamma-ray. The latter alternative would be the highest spin-change gamma decaying isomer yet discovered and both are unusual in the very high energy transition involved.