Sum-fit method of analysis of nuclear decay spectra affected by extending dead-time

We present a method of analysis of nuclear decay spectra affected by extending dead-time, in which a non-trivial, but relatively simple correction for dead-time losses is applied to produce an estimate of the spectrum in the absence of dead-time, with negligible bias and negligible deviation from the original Poissonian statistics. The method requires the measurement of arrival times of all observed decay events, but it does not require any knowledge about the dead-time or the nuclear decay. The parameters of nuclear decay can be determined in a subsequent straight-forward analysis of the estimated dead-time free spectra, individually or in combinations. In a typical realistic situation this approach is expected to contribute 0.001% or less to the systematic error of nuclear half-life or activity. Compared to the exact method of analysis presented in our earlier publication, the present method is much easier to implement and produces the results significantly faster.