The Gamow-Teller beta decay of neutron-deficient even isotopes of tin

With the use of the 58Ni + 50Cr fusion-evaporation reaction and chemically selective on-line mass separation, the EC/β+ decay of 104Sn was studied by γ-ray and conversion-electron spectroscopy. In the course of these studies, a new 15.7-s isomeric state of 104In was observed. Reinvestigation of the β-decays of the two heavier even isotopes of tin, produced in the 58Ni + 58Ni reaction and mass separated without chemical discrimination, brought new information on the decay of 106Sn and 108Sn. The QEC values of 104Sn, 106Sn and 108Sn were determined to be 4550(+300-250) keV, 3200±100 keV and < 2270 keV, respectively. In the data analysis, the emphasis is put on the identification of the 0+ → 1+ Gamow-Teller β transitions and determination of their strengths. For 104-110Sn, the total Gamow-Teller strengths are measured to be 20% to 30% of that predicted by the single-particle shell model with the inclusion of pairing correlations and core polarization. Predictions of the decay properties of the as yet unobserved 102Sn and 100Sn are made. (orig.)