A periodreactor period of time also called short life during which the number of radionuclideUnstable nuclide spontaneously decaying without external eff... nuclei reduces to 1/e (e = 2.718…, base of natural logarithms). The life is equal to the reciprocal of the decay constantThe decay constant of radioactive decay is equal to the reci... . Life and half-lifeThe period during which half of the nuclei decay in a quanti... T are related as follows:
τ= T/ln 2 ≈ 1.44·T.