Eur. Phys. J. Special Topics 150, 87-88 (2007)
https://doi.org/10.1140/epjst/e2007-00273-9

Structure of ²³¹Ac: Measurements of level half-lives

¹ Instituto de Estructura de la Materia, CSIC, Serrano 113 bis, 28006 Madrid, Spain
² Dept. of Radiation Sciences, ISV, Ångström laboratory, Lägerhyddsvagen 1, P.O. Box 535, 751 21 Uppsala, Sweden
³ EP Division, CERN, 1211 Geneva 23, Switzerland
⁴ Dept. of Physics, University of Warsaw, 00 681 Warsaw, Poland
⁵ Dept. of Chemistry and Physics, University of Oslo, P.O. Box 1033, 0315 Oslo, Norway
⁶ Instituto de Física Corpuscular, CSIC-University of Valencia, 46100 Burjassot, Spain

Received: 31 January 2007
Published online: 8 December 2007

Abstract

There is lack of knowledge of the structure of the ²³¹Ac nucleus located in the upper border of the island of octupole deformation centered around A = 225. We have populated the excited states in ²³¹Ac by beta-decay from the parent ²³¹Ra produced at ISOLDE, CERN. The low-energy structure of ²³¹Ac has been investigated by means of γ, conversion electrons, γ-γ and γ-e^- spectroscopy. We report here in the precise determination in ²³¹Ac of the half-life of the most intensively populated states by the Advanced Time Delayed ββγ(t) technique.