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HK: Fachverband Physik der Hadronen und Kerne

HK 46: Kernphysik / Spektroskopie

HK 46.4: Vortrag

Donnerstag, 15. März 2007, 15:00–15:15, B

Search for the shape-isomer in ²³⁵U — •Stephan Oberstedt¹, Andreas Oberstedt², and Michael Gawrys³ — ¹EC-JRC IRMM, B-2440 Geel — ²Dept. of Natural Science, Örebro University, S-70182 Örebro — ³Dept. of Fundam. Physics, Chalmers Uni. of Technology, S-41296 Göteborg

The need to improve the knowledge about the double- or even triple-humped fission barrier initiated a systematic investigation of shape-isomeric decay modes in actinide nuclei. At present, the population and the principle decay mode in odd-A uranium isotopes is of particular interest for improving nuclear reaction models. Neither of both is known today, and different half life systematics give predictions, which range across up to five orders of magnitude.

Recently, the IRMM isomer spectrometer NEPTUNE [1] was used to search for the shape-isomer in ²³⁵U using the reaction ²³⁴U(n, f) at E_n = 0.95 and 1.27 MeV. For the first time shape-isomeric fission with a tentative half life T_1/2 = (4.5 ± 0.3) ms has been observed

 
S. Oberstedt et al., DPG Spring Meeting, Hadrons and Nuclei, München (2006) HK57.4