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For the first time, detailed decay-spectroscopic investigations were performed for the very neutron-deficient N=50 nuclide 9SCd. The 9SCd activity was produced in spallation reactions between 600 MeV protons and a natural tin target, yielding a 9SCd beam intensity of 10 to 60 atoms/s at the collector of the ISOLDE massseparator. By means of 7-ray and conversion-electron spectroscopy, 19 transitions were found to follow the /?+/EC decay 98Cd--*9SAg. The transitions at 61 and 107 keV were shown to be M 1(+ E 2) and E2, respectively, and the 98Cd half-life was measured as 9.2+0.3s. The QEC value of 9SCd is determined semiempirically and is compared to model predictions together with the measured QEc values of the neighbouring cadmium isotopes 1~176176 and the N=50 isotones 92M0, 94Ru, and 96pd, taken from the literature. The newly established decay scheme of 98Cd includes 9 excited states of 98Ag. Four states at 1691, 1861, 2164, and 2544 keV are directly fed by 0"~ 1 + Gamow-Teller beta transitions with a summed strength +0 s of 3.5-o17. This value corresponds to 25_+5% of the strength predicted for the GT transformation of a g9,2 proton (in 98Cd) into a g7/2 neutron (in 98Ag) by the extreme single-particle shell model. The GT-strength splitting and quenching, observed for 98Cd, are compared with the corresponding data for lighter even-even N = 50 isotones, and are discussed with reference to the predictions of more sophisticated nuclear models. We find that only in some cases it is possible to explain qualitatively the observed GT strength distribution and its total magnitude without renormalizing the free-neutron value of the axial-vector coupling constant.

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