Lifetime measurement of the 2 P-3(0) state in He-like uranium

• Published in: Physica scripta 2013-09, Vol.T156
• Main Authors: Reuschl, R., Gassner, T., Spillmann, U., Braeuning-Demian, A., Ananyeva, A., Beyer, H., Blumenhagen, K-H, Chen, W., Hagmann, S., Hegewald, M., Indelicato, P., Schwemlein, M., Toleikis, S., Trassinelli, Martino, Trotsenko, S., Winters, D., Winters, N., Stoehlker, Th
• Format: Article
• Language: English
• Subjects: Condensed Matter; Physics
• ISSN: 0031-8949; 1402-4896
• DOI: 10.1088/0031-8949/2013/T156/014024

In recent years for the fundamental theory of quantum electrodynamics, considerable progress in the evaluation of higher order corrections has been achieved-not only for hydrogen-but also for helium-like systems-up to very heavy nuclei. We were aiming at a more precise determination of the lifetime of the metastable 2 P-3(0) state in He-like uranium which has a calculated value of 57.3 ps [1, 2]. From the lifetime it is possible to derive the energy of the state. In October 2011 we were able to perform a first test experiment at GSI, Darmstadt to study the feasibility of a new experimental detection technique. This advanced set-up consists of two state-of-the-art energy-, time-and position-sensitive germanium detectors [3] in combination with collimators in a Soller-slit like assembly. A beam of U91+-ions at an energy of 290MeV u(-1) is passed through a thin nickel foil in the interaction chamber. From the decrease in intensity as a function of the target distance one may extract a decay curve from which the lifetime can be derived. The advantages of this new set-up, in comparison to former experiments [4, 5] will be discussed and the results of a preliminary data analysis will be presented.