Doppler shift attenuation method analysis with the narrow gate on transitions below procedure

A new analysis procedure is proposed for the Doppler Shift Attenuation Method in γ–γ coincidences, which allows the determination of the lifetime of nuclear levels without the influence of sidefeeding. The procedure consists in taking as the gate, the non Doppler shifted portion of a γ-transition from the level being studied and in describing the suppression effect in the line shape of a coincident transition above it, with respect to that obtained with a gate including the whole line shape. The procedure, named Narrow Gate on Transitions Below (NGTB), can be efficiently employed using the current large γ-multiarrays.