High-precision branching ratio measurement for the superallowed ?+ emitter 62-Ga

Finlay, Paul E.J.
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University of Guelph

A high-precision branching ratio measurement for the superallowed ? + decay of 62Ga was performed at the Isotope Separator and Accelerator radioactive ion beam facility. An array of 20 high-purity germanium detectors known as the 8? spectrometer was employed to detect the ? rays emitted following the Gamow-Teller and non-analog Fermi decays of 62Ga, while the plastic scintillator array known as SCEPTAR was used to detect the emitted ?-particles. A total of 32 ? rays were identified, establishing the superallowed branching ratio to be 99.859(8)%. Combined with the most recent half-life and Q-value measurements for 62Ga, this branching ratio yields an 'ft'-value of 3074.3 ± 1.1 s. Comparisons between the superallowed 'ft'-value determined in this work and the world average Ft are made, providing a benchmark for the refinement of theoretical models used to describe isospin-symmetry breaking in A >= 62 nuclei.

high-precision branching ratio measurement, superallowed ? + decay, 62Ga, theoretical model