Frankfurt 2014 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 46: Poster

HK 46.27: Poster

Donnerstag, 20. März 2014, 16:00–18:00, HZ Poster

Velocity distribution in Recoil-Distance Doppler-Shift experiments — •Thomas Braunroth, Matthias Hackstein, Alfred Dewald, Claus Müller-Gatermann, Christoph Fransen, and Dorothea Wölk — Institut für Kernphysik, Universität zu Köln, Germany

The Recoil-Distance Doppler-Shift (RDDS) technique is a well established method to measure lifetimes of excited nuclear states in the pico-second range. In standard RDDS experiments at non-relativistc beam-energies, the velocities of the emerging recoils are usually distributed narrowly around a mean velocity v = ⟨ v ⟩_v. Under these circumstances, the effect of the velocity distribution is neglectable and the assumption that all nuclei move with the average velocity is justified. In this poster we investigate the influence of broader velocity distributions on lifetimes determined using the standard lifetime analysis-method DDCM. This can be observed, e.g., in experiments with thick targets. In particular, it is shown that the effect of the velocity distribution on the deduced lifetime is minimised at the maximum amplitude of the derivative of the decay function.
This work was partly supported by the BMBF (Germany) under Contract no. 05P12PKFNE.