High-Precision Half-life Measurements for the Superallowed β⁺ Emitter ¹⁴O

¹ Department of Physics, University of Guelph, Guelph, Ontario N1G 2W1, Canada
² Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
³ Department of Astronomy & Physics, Saint Mary’s University, Halifax, Nova Scotia B3H 3C3, Canada
⁴ TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
⁵ Centre d’Etudes Nucléaires de Bordeaux Gradignan-Université Bordeaux 1-UMR 5797 CNRS/IN2P3, Chemin du Solarium, BP 120, F-33175 Gradignan Cedex, France
⁶ GANIL, CEA/DSM-CNRS/IN2P3, Bvd Henri Becquerel, 14076 Caen, France
⁷ Department of Physics, Queen’s University, Kingston, Ontario K7L 3N6, Canada

^a e-mail: alaffole@uoguelph.ca

Published online: 20 March 2014

Abstract

The half-life of ¹⁴O, a superallowed Fermi β⁺ emitter, has been determined via simultaneous γ and β counting experiments at TRIUMF’s Isotope Separator and Accelerator facility. Following the implantation of ¹⁴O samples at the center of the 8π spectrometer, a γ counting measurement was performed by detecting the 2313 keV γ-rays emitted from the first excited state of the daughter ¹⁴N using 20 high-purity germanium (HPGe) detectors. A simultaneous β counting experiment was performed using a fast plastic scintillator positioned directly behind the implantation site. The results, T_½(γ) = 70:632 ± 0:094 s and T_½(β) = 70:610 ± 0:030 s, are consistent with one another and, together with eight previous measurements, establish a new average for the ¹⁴O half-life of T_½ = 70:619 ± 0:011 s with a reduced χ² of 0.99.