A graphical analysis of decay curves measured by the Doppler-shift recoil distance method

The present method of analyzing the decay curves is a direct extension of the method of linearizing an exponential decay using a semilog plot. On semilog graph paper experimental points of a decay curve can be approximated using a smooth curve having a slowly varying slope with recoil distance. In addition, the lifetime of an excited state can be expressed as the product of two factors: the reciprocal of the slope of a semilog graph and a correction factor for feeding time. These factors can be evaluated from two semilog graphs for the successive transitions, feeding and de-exciting a given excited state. This factorization simplifies the analysis of the decay curves and brings the method a considerable tolerance as regards their experimental errors. The present method has been applied to the decay curves measured in 124,126Ce and 132,134Nd.