The Gamow-Teller beta decay of 100Cd

Neutron-deficient isotopes of cadmium were produced in the p(600 MeV)+natSn spallation reaction. The ISOLDE facility provided mass-separated beams of these isotopes. The production yield was 103 to 104 atoms/s for 100Cd and roughly two orders of magnitude less for 98Cd. The properties of the 100Cd → 100Ag decay were studied in detail by X-ray, γ-ray and conversion electron spectroscopy. Forty nine γ-transitions were assigned to this decay, and all but five of them were placed in the decay scheme. The half-life was determined to be 49.1±0.5 s. The QEC value of 3890±70 keV was deduced from a comparison of experimental and theoretical β+/(EC+β+) probability ratios. Seven 0+ → 1+ Gamow-Teller transitions with log ft values between 3.5 and 4.9 were identified. The total (summed) strength is about five times smaller than predicted by the shell model for the transformation of a g9/2 proton into a g7/2 neutron. The quenching of the Gamow-Teller strength and other questions of nuclear structure are discussed for the 100Cd decay. The properties of 98Cd are inferred by extrapolation of 104,102,100Cd data, and some preliminary experimental results on 98Cd decay are presented. (orig.)