Author/Authors :
L.M. Fraile، نويسنده , , M.J.G. Borge، نويسنده , , H. Mach، نويسنده , , R. Boutami، نويسنده , , A.J. Aas، نويسنده , , B. Fogelberg ، نويسنده , , L.M. Garc??a-Raffi، نويسنده , , I.S. Grant، نويسنده , , K. Gulda، نويسنده , , E. Hageb?، نويسنده , , W. Kurcewicz، نويسنده , , J. Kvasil، نويسنده , , M.J. L?pez، نويسنده , , G. L?vh?iden، نويسنده , , T. Mart??nez، نويسنده , , B. Rubio، نويسنده , , J.L. Tain، نويسنده , , O. Tengblad، نويسنده , , ISOLDE Collaboration ، نويسنده ,
Abstract :
The structure of 231Ra, the heaviest odd Ra nucleus currently accessible for detailed spectroscopic investigation, has been studied in the β− decay of 231Fr. The main purpose has been to verify whether fast B(E1) rates and significant octupole correlations recently established in 229Ra persist in 231Ra. The excited states in 231Ra have been determined for the first time. Spins and parities have been deduced from conversion electron measurements, while level half-lives in the ps and ns ranges have been measured with the Advanced Time Delayed βγγ(t) method. The moderately fast B(E1) rates found for transitions connecting the lowest-lying Kπ=5/2± and Kπ=1/2± bands, reveal the persistence of octupole collective effects in 231Ra, although the B(E1) rates are lower than in 229Ra. These findings reinforce the differences in the B(E1) systematics between isotonic Ra and Th nuclei.
Keywords :
spin-parities , rotational bands , B(XL) , Advanced Time Delayed ???(t) method , GE , Quasiparticle-plus-phonon model , Si(Li) , 6p2n) mass separation] , BaFView the MathML source detectors , View the MathML source , RADIOACTIVITY , I(CE) , ?–? coincidences , ?–e? coincidences , View the MathML source , ICC multipolarities , Deduced View the MathML sourceRa levels , Measured View the MathML source , mini-orange spectrometer
