APCAD - Analysis Program for the Continuous-Angle DSAM

We present a novel method for the analysis of Doppler-broadened γ-ray lineshapes observed by position-sensitive detector systems with the purpose to determine nuclear level lifetimes. This advance of the well-known Doppler-Shift Attenuation Method (DSAM) is specifically tailored to experiments employing γ-ray tracking detectors and takes advantage of the position resolution of these detector systems. The novel continuous-angle Doppler Shift Attenuation Method (caDSAM) is implemented in the comprehensive computer program APCAD for the calculation of Doppler-broadened γ-ray lineshapes, their fit to experimental data and extraction of level lifetimes. Extensions of the method qualifying it for measurements with radioactive and relativistic ion beams as well as for the measurement of “long” level lifetimes of the order of ∼200 ps are presented.