Eur. Phys. J. A (2007) 34: 355-361
https://doi.org/10.1140/epja/i2007-10512-5

Regular Article - Experimental Physics

Isomeric states in ²¹⁴Th and ²¹³Th

¹ Gesellschaft für Schwerionenforschung mbH, D-64291, Darmstadt, Germany
² St. Petersburg State University, 198504, Stari Peterhof, St. Petersburg, Russia
³ Institut für Kernphysik, Johann Wolfgang Goethe-Universität, D-60438, Frankfurt am Main, Germany
⁴ Department of Nuclear Physics and Biophysics, Comenius University, SK-84248, Bratislava, Slovakia
⁵ Japan Atomic Energy Agency, 319-1184, Tokai, Ibaraki, Japan

^* e-mail: S.Hofmann@gsi.de

Received: 1 November 2007
Accepted: 28 December 2007
Published online: 24 January 2008

Abstract

Isomeric states in ²¹⁴Th and ²¹³Th were identified by means of γ -rays measured in delayed coincidence with the implanted evaporation residues. These were produced in irradiations of ¹⁶⁴Dy with ⁵⁴Cr projectiles and separated in-flight by the velocity filter SHIP. An isomeric state of I ^π = 8⁺ with a half-life of (1.24±0.12) μs was identified in ²¹⁴Th . The configuration π[1h _9/2 ⊗ 2f _7/2] was assigned to this state. An isomeric state with a half-life of (1.4±0.4) μs was observed in ²¹³Th . Tentatively it was assigned to an I ^π = 13/2⁺ state.