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Identification of the slow E3 transition 136 Cs m → 136 Cs with conversion electrons

ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA
Physical Review C (Impact Factor: 3.72). 07/2011; 84:014329. DOI: 10.1103/PhysRevC.84.014329

ABSTRACT We performed at ISOLDE the spectroscopy of the decay of the 8 − isomer in 136 Cs by γ and conversion-electron detection. For the first time the excitation energy of the isomer and the multipolarity of its decay have been measured. The half-life of the isomeric state was remeasured to T 1/2 = 17.5(2) s. This isomer decays via a very slow 518-keV E3 transition to the ground state. In addition to this, a much weaker decay branch via a 413-keV M4 and a subsequent 105-keV E2 transition has been found. Thus we have found a new level at 105 keV with spin 4 + between the isomeric and the ground state. The results are discussed in comparison to shell-model calculations.

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