Properties of $\gamma$-decaying isomers and isomeric ratios in the $^{100}$Sn region

International audience; Half-lives and energies of γ rays emitted in the decay of isomeric states of nuclei in the vicinity of the doubly magic Sn100 were measured in a decay spectroscopy experiment at Rikagaku Kenkyusho (The Institute of Physical and Chemical Research) of Japan Nishina Center. The measured half-lives, some with improved precision, are consistent with literature values. Three new results include a 55-keV E2γ ray from a new (4+) isomer with T1/2=0.23(6)μs in Rh92, a 44-keV E2γ ray from the (15+) isomer in Ag96, and T1/2(6+)=13(2) ns in Cd98. Shell-model calculations of electromagnetic transition strengths in the (p1/2,g9/2) model space agree with the experimental results. In addition, experimental isomeric ratios were compared to the theoretical predictions derived with an abrasion-ablation model and the sharp cutoff model. The results agreed within a factor of 2 for most isomers. From the nonobservation of time-delayed γ rays in Sn100, new constraints on the T1/2, γ-ray energy, and internal conversion coefficients are proposed for the hypothetical isomer in Sn100.