Gamow-Teller decay of 118Pd and of the new isotope 120Pd

Abstract

With the use of the proton-induced fission of 238U and the ion guide-fed on-line mass separation, even- A isotopes of palladium with high neutron excess were studied by means of γ-ray and conversion-electron spectroscopy. The decay of 118Pd was reinvestigated in detail, and evidence for the new isotope 120Pd, with a half-life T 1 2 = 0.5 ± 0.1 s , was found. As established for 118Pd and tentatively shown for 120Pd, the β-decay of these two isotopes proceeds mainly through 0 + → 1 + Gamow-Teller transitions with log ft values between 4.2 and 4.7. The strength of individual transitions has been compared with the predictions of the shell-correction model with a deformed Woods-Saxon potential and pairing residual interaction. The total GT strength was found to be quenched with respect to both the deformed shell-model and spherical-quasiparticle random-phase-approximation predictions.