Decay Constant
Compute the radioactive decay constant, λ = ln(2)/T½, from the half-life (T½). The constant λ is the probability of a nucleus decaying per unit time — the larger it is, the more unstable the isotope and the shorter its half-life. It links the half-life (time for half the nuclei to decay) to the activity and to the exponential decay law. Enter the isotope's half-life.
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Decay constant
The decay constant λ = ln(2)/T½ is the probability that a radioactive nucleus decays per unit of time — the fundamental 'pace' of radioactive decay. It is the link between two ways of describing the same thing: the half-life T½ (the intuitive time for half of the nuclei to decay) and the law of exponential decay N(t) = N₀·e^(−λt). The factor ln(2) ≈ 0.693 shows up because what we want is the time at which N falls to half its value. Highly unstable isotopes have a high λ and extremely short half-lives (fractions of a second); nearly stable isotopes have a tiny λ and half-lives of billions of years (uranium-238, for instance, at 4.5 billion years). The constant λ feeds directly into the activity calculation (A = λN). Enter the half-life of the isotope.
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The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.