Bochum 2018 – wissenschaftliches Programm
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HK: Fachverband Physik der Hadronen und Kerne
HK 52: Poster
HK 52.37: Poster
Donnerstag, 1. März 2018, 16:30–18:45, Audimax Foyer
Lifetime measurements with the DSA method — •Maximilian Droste, Andreas Vogt, Konrad Arnswald, Peter Reiter, Claus Müller-Gatermann, and Alfred Dewald — Institute for Nuclear Physics, University of Cologne
The Doppler shift attenuation method (DSAM) is the method of choice for the measurement of lifetimes of nuclear excited states in the sub-picosecond region. DSAM experiments employ thin production targets mounted on a thick stopper foil (backing) in which the recoiling nuclei of interest slow down and stop in a well-defined manner. The emission of γ rays during this time leads to the observation of a Doppler-broadened lineshape whose details are sensitive to the lifetime and the time evolution of the population of the level of interest. The APCAD analysis code (Analysis Programm for Continuous-Angle DSAM) [1] is a versatile tool for the analysis of γ-ray lineshapes. The code simulates the slowing-down history of the recoiling ions and fits the distinct lineshapes to the observed spectra. Excited states in 20Ne and 47V were populated in fusion-evaporation reactions with the tandem accelerator of the IKP, University of Cologne to test and benchmark the analysis procedures with APCAD. Different stopping approximations (SRIM and GEANT4) are investigated and the impact of nuclear and electronic stopping powers on the fitted lineshapes is studied in detail. Results of these variations as well as a first results for the lifetime of the 4+ state of 48Cr will be presented. A.V. supported by BCGS. [1] C. Stahl et al., Comput. Phys. Commun. 214 (2017) 174-198.