$\alpha$ decay of ${^{243}\mathrm{Fm}}_{143}$ and ${^{245}\mathrm{Fm}}_{145}$, and of their daughter nuclei
Résumé
Nuclear structure of Fm243, Fm245, and their daughter nuclei were investigated via detection of their radioactive decays, α, γ, and spontaneous fission. Measured α-decay energies, half-lives, and branching ratios improve the literature data significantly. A signature for detection of the hitherto unknown Cm235 was found in the α-decay chains from Fm243. Two groups of α events with average energies of 6.69(2) MeV and 7.01(2) MeV and with a half-life of T1/2=300−100+250 s are suggested to originate from Cm235. Tentative decay schemes for Fm243, Cf239, Cm235, and Fm245, Cf241 isotopes are suggested based on the present experimental data. Systematical trends of single-particle states in N=141 isotones of Z=92–98 nuclei are discussed.