Eur. Phys. J. A (2008) 36: 279-288
https://doi.org/10.1140/epja/i2008-10592-7

Regular Article - Experimental Physics

Fission and ternary cluster decay of hyper-deformed ⁵⁶Ni

¹ Hahn-Meitner-Institut-GmbH, Berlin, Germany
² Flerov Laboratory for Nuclear Reactions, JNR, Dubna, Russia
³ IPHC, Département de Recherches Subatomiques, IN2P3-CNRS, UMR7178, Université Louis Pasteur, Strasbourg, France
⁴ Subatech, UMR, Université-IN2P3/CNRS-Ecole des Mines, Nantes, France
⁵ Laboratori Nationali di Legnaro, Legnaro, Italy
⁶ St. Petersburg University, St. Petersburg, Russia

^* e-mail: oertzen@hmi.de

Received: 18 April 2008
Accepted: 12 May 2008
Published online: 24 June 2008

Abstract

Coincidences between two heavy fragments have been measured from the fission of ⁵⁶Ni compound nuclei formed in the ³²S + ²⁴Mg reaction at E _lab( ^32S ) = 165.4 MeV. A unique experimental set-up consisting of two large-area position-sensitive (x, y) gas detector telescopes has been used allowing the complete determination of the observed fragments and their momentum vectors. In addition to binary fission events with subsequent particle evaporation, narrow out-of-plane correlations are observed for two fragments emitted in purely binary events and in events with a missing charge consisting of 2α - and 3α -particles (¹²C). These events are interpreted as ternary cluster decay from ⁵⁶Ni nuclei at high angular momenta through hyper-deformed shapes.