The nuclear structure of 223Fr

Abstract

The γ-rays following the β- decay of Rn-223 have been investigated by means of γ-ray singles including multispectrum analysis, and γγ-coincidence measurements using Ge detectors. Multipolarities of 38 transitions in Fr-223 have been established by measuring conversion electrons with a mini-orange electron spectrometer. Most of the observed transitions could be placed in a level scheme comprising 53 excited states of Fr-223. The level structure is interpreted in terms of K(π) = (3/2)± and (1/2)± parity doublet bands, and a second K(π) = (3/2)± higher-lying parity doublet. The experimental data are compared with the theoretical predictions of the reflection-asymmetric rotor model.