High-precision half-life determination of $^{14}$O via direct $\beta $ counting
- Sharma, S. et al
- arXiv:2204.06668
| (Color online) Measured count rate of a $^{90}$Sr calibration source as a function of applied voltage for different discriminator threshold settings. The plateau region was determined to be between 2300~V to 2480~V, as indicated by the vertical bands. The maximum variation in counting rate observed in this region was less than 0.64$\%$ (horizontal bands). |
| (Color online) a) Dead-time corrected $^{14}$O decay data (points) and resulting fit (line) for one cycle: 140~s collection, 24.3~min decay, 70~mV threshold and 2450~V detector bias. b) Residuals (points, ($y_i$-$y_{fit}$)/$\sigma_i$) obtained from the fit to the experimental data in a) and zero (line) to guide the eye. For clarity, statistical uncertainties on the data are not shown. |
| (Color online) Deduced half-life versus cycle number for the 124 decay cycles collected and analyzed in the present experiment. A weighted average of them yields $T_{1/2}$($^{14}$O)~=~70619.2(70)~ms (solid and dashed lines) with a $\chi^2$/$\nu$~value of 1.13 for 123 degrees of freedom. |
| (Color online) Systematic plot that groups the half-lives deduced from the individual cycles data according to the particular electronic settings used in the experiment (see Table~\ref{Systematic_Table} for a detailed description of each point). The solid and dashed lines correspond to the weighted average half-life obtained from the entire data set and its statistical uncertainty $T_{1/2}$~=~70619.2(70)~ms. The $\chi^2$/$\nu$~value for each of the electronic settings is indicated. |
| (Color online) Half-life of $^{14}$O versus the leading number of channels removed from the analysis. The weighted average $T_{1/2}$~=~70619.2(70)~ms of the 124 cycles with no channels removed (solid and dashed lines) is overlayed for comparison. As these data are not statistically independent, a weighted average of them cannot be determined. |
| (Color online) Comparison of the present result with the previous most precise measurements of the half-life of $^{14}$O from Refs.~\cite{Cla73,Bec78,Wil78,Gae01,Bar04,Bur06,Tak12,Laf13}. The red solid line is the new world average that includes the present result and the dashed lines represent the $\pm$1$\sigma$ uncertainties. The $\chi^2$/$\nu$~value for the set is 0.87 for 8 degrees of freedom. |