The decay constant is given by the formula $\lambda = \frac{0.693}{t_{1/2}}$, where $t_{1/2}$ is the half-life of the isotope.
For electron capture, we have:
\[\lambda_{\epsilon} = \frac{0.693}{1.4 \times 10^{9} \, \text{y}} = 0.495 \times 10^{-9} \,
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