Lawrence Berkeley National Laboratory

Beta-delayed proton decays of the nuclides P-27 and Cl-31 were measured using the helium-jet recoil collection technique and low-energy particle identification detector telescopes. In P-27, two new proton groups at 466+/-3 keV and 612+/-2 keV, with intensities of 9+/-2% and 97+/-3% relative to the main (100%) group at 731+/-2 keV, were discovered. Additionally, during the P-27 experiments, a new proton transition was identified following the beta decay of P-28. This group, at a proton energy of 1452+/-4 keV, had a 2+/-1% intensity relative to the 100% group at 679+/-1 keV. A total P-27 beta-delayed proton branch of 0.07% was estimated. The experimental Gamow-Teller beta-decay strengths of the observed transitions from P-27 were compared to results from shell model calculations. A search for new proton transitions in Cl-31, the next member of this A = 4n + 3, T-z = -3/2 series, was unsuccessful. However. several proton peaks that had been previously assigned to Cl-31 decay were shown to be from the decay of Si-25.