Half-life of ${}^{14}\mathrm{O}$

We have measured the half-life of ${}^{14}\mathrm{O}$, a superallowed $(0^{+}\to 0^{+})$ β decay isotope. The ${}^{14}\mathrm{O}$ was produced by the ${}^{12}\mathrm{C}$(${}^3\mathrm{He}$,$n$)${}^{14}\mathrm{O}$ reaction using a carbon aerogel target. A low-energy ion beam of ${}^{14}\mathrm{O}$ was mass separated and implanted in a thin beryllium foil. The beta particles were counted with plastic scintillator detectors. We find $t_{1/2}=70.696\pm 0.052$ s. This result is $1.5\sigma$ higher than an average value from six earlier experiments, but agrees more closely with the most recent previous measurement.

Figure 1

The arrangement of the detectors, counting chamber, and target foil positioned for decay data acquisition. The vacuum chamber enclosing the transfer arm is not shown, nor are the photomultiplier tubes and wrapping on the scintillators and light guides.

Figure 2

Decay data and the fit curve for a single run for one detector (C) in one dead time channel (400 ns, nonextending).

Figure 3

The fraction of counts in detector D lost below threshold as a function of the count rate in the detector.

Figure 4

The half-life results for fits to data from each detector when allowing different combinations of contaminant species to vary in the fits. Each point is an unweighted average of the half-life results from the 29 data cycles in which the data is restricted to an initial detector count rate of 20 kHz.