The yrast spectroscopy of 209Rn

The yrast spectroscopy of ²⁰⁹Rn has been investigated to an excitation energy of over 7 MeV and to a spin of $\text{51}\text{2}$. The existence of six isomers has been established: $\text{1174}\text{keV}\text{(J}{}^{\mathrm{\pi }}\text{=}\text{13}\text{2}{}^{\mathrm{+}}\text{, τ}{}_{\mathrm{<mtext>m</mtext>}}\text{= 19.3 ± 1.9 μ}\text{s}\text{), 1687}\text{keV}\text{(}\text{19}\text{2}{}^{\mathrm{?}}\text{, 1.0 ± 0.3}\text{ns}\text{), 2419}\text{keV}\text{(}\text{21}\text{2}{}^{\mathrm{+}}\text{, 12.6 ± 0.3}\text{ns}\text{20 ± 3}\text{ns}\text{, 3637}\text{keV}\text{(}\text{35}\text{2}\text{, 4.3 ± 0.4 μ}\text{s}\text{)}\text{and}\text{4834}\text{keV}\text{(}\text{41}\text{2}{}^{\mathrm{?}}\text{, 14.4 ± 0.5}\text{ns}\text{)}$. Shell-model calcu are used to explain the observed structure. E3 and M2 transitions in ²⁰⁹Rn and neighbouring nuclei are discussed.