Measurement of the gamma-ray probability per decay of I-126

The emission probabilities per decay of the main γ-ray transitions, as well as the β−/(β+, EC) branching ratio and half-life of 126I have been measured. β branch measurements were carried out in a 4π(PC)β–γ coincidence system consisting of a proportional counter coupled to a pair of 3×3 inch NaI(Tl) crystals. The electron capture branch was measured in an X–γ coincidence system using two 3×3 inch NaI(Tl) crystals. Gamma-ray measurements were performed in a calibrated HPGe spectrometry system. All the uncertainties were treated rigorously by means of covariance analysis.