Lifetime analysis using the Doppler-shift attenuation method with a gate on feeding transition

A method for the description of the γ-ray line-shapes observed in coincidence lifetime measurements using the Doppler-shift attenuation method is proposed. The case where a gate is set on a transition which feeds directly the level of interest is considered in detail. The formalism for lifetime determination in the general framework of the differential decay-curve method is developed. The method is illustrated by an application to data simulated for the case of the 116Cd(16O, 4n)128Ba reaction at a beam energy of 72 MeV observed with a multi-detector set-up.