Spectroscopic investigations of the decay 223Ra → 219Rn

Internal conversion electron spectra of the transitions 4.4 keV, 10.0 keV, 14.4 keV, and 324.1 keV in the decay ²²³Ra → ²¹⁹Rn were measured. E2/M1 mixing ratios of these γ-transitions were deduced from conversion electron intensity ratios: δ² = 3.8(4) · 10^?3, 2.35(18) · 10^?3, 12.85(36) · 10^?3, 0.23(3). The half-lives of the 4.4 keV and 14.4 keV levels were determined as $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{= 15.4(1.3)}$ nsec and 0.875(30) nsec. Reduced transition probabilities were calculated and compared to the Weisskopf estimates. αγ angular correlation measurements of the transitions 269.6 keV, 324.1 keV, and 338.6 keV and an αγ linear polarization measurement of the 269.6 keV transition were performed for spin determination. We assign $\text{I =}\text{7}\text{2}$ to the ²¹⁹Rn ground state and $\text{I =}\text{5}\text{2}$ or $\text{9}\text{2}$ to the 269.6 keV state. All other low excitations including the 338.6 keV level have spins $\text{I =}\text{5}\text{2}$, $\text{7}\text{2}$, or $\text{9}\text{2}$. The spins of the states 158.7 keV and 14.4 keV are equal. The ²²³Ra ground state spin is $\text{I =}\text{7}\text{2}$ or $\text{9}\text{2}$. The possibility of an interpretation of the transitional nucleus ²¹⁹Rn in the frame of the collective model is discussed.