Intensity of a weak 519-keV gamma ray following beta decay of the superallowed emitter Ar-34 determined via the S-33(p,gamma)Cl-34 reaction

The predominant branch in the beta decay of Ar-34 is the superallowed 0(+) -> 0(+) transition to the ground state of Cl-34. To determine its important branching ratio one must first establish the ratios for the competing Gamow-Teller branches based on the measured intensities of gamma rays subsequently emitted from the excited states they populate in Cl-34. The strongest of these branches populates the 1+ state at 666 keV in Cl-34, which has three possible gamma-decay paths. We report here a measurement of the decay of this state, which we populated via resonant proton capture in the reaction S-33(p,gamma)Cl-34. We find that the intensity of the 519-keV gamma-ray path is 1.46(19)% relative to that of the 666-keV path. This result is critical to new precise measurements of the superallowed decay of 34Ar.