The decay of 223Ra and its daughter products : (I). The decay of 223Ra

Abstract

The Ge(Li) γ-ray spectrum of 223Ra was found to consist of 32 γ-rays whose energies and absolute quantum intensities were determined. The α-ray spectrum was studied using Au(Si) detectors. Conversion line studies at ≈ 0.1 % resolution in momentum on the Chalk River π√2 β-spectrometer yielded the multipolarities of the following more prominent transitions (keV): 110.8 (E2), 122.30(M1 + 1.8 % E2), 144.19 (M1 + 1.5 % E2), 154.18 (M1), 158.62 (M1 + 3.8 % E2), 269.41 (M1 + 2.4% E2), 323.88 (M1 + 3 % E2) and 338.30 (M1 + < 9 % E2). With solid state detectors in both channel, α-γ directional correlations on the cascades 5.603 MeV α-269.4 keVγ, 5.712 MeV α-144.2 keVγ and 5.712 MeV α-154.2 keVγ yielded the following parameters respectively: A 22 = 0.195 ± 0.045, A 44 = 0.005 ± 0.048; A 22 = 0.322 ± 0.042, A 44 = −0.074 ± 0.050; A 22 = −0.099 ± 0.029, A 44 = 0.008 ± 0.033. The correlations and multipolarities suggest most probable assignments of the spins and parities of the first seven levels in su219Rn as 3 2 + ( g.s.) , 7 2 + (4.4 keV) , 5 2 + (14.4 keV) , 5 2 + or 7 2 + (126.7 keV) , 5 2 + (158.6 keV) , 3 2 + (269.4 keV) and 3 2 + or 5 2 + (338.3 keV) respectively, A decay scheme involving 19 excited states is proposed. The introduction of two new levels at 342.9 keV and 447.0 keV is discussed.