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VOLUME 85 (2007) | ISSUE 3 |
PAGE 168
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Collinear Ternary Cluster Decay of Hyper-deformed 60Zn at High Angular Momentum
V. I. Zherebchevsky+*∇, W. von Oertzen*∇, D. V. Kamanin
+St. Petersburg University, 198504 St. Petersburg, Russia *Hahn-Meitner-Institut-GmbH, D-14109 Berlin, Germany ∇Fachbereich Physik, Freie Universität, 14195 Berlin, Germany, Flerov laboratory for Nuclear Reactions, 141980 Dubna, Russia
PACS: 25.60.Dz, 25.70.Gh, 27.50.+e
Abstract
Binary and ternary cluster decay of 60Zn compound nuclei at
high angular momentum, formed in the 36 Ar +24Mg reaction
at E lab(36Ar) = 195 MeV, has been measured in a unique
kinematic coincidence set-up consisting of two large area position sensitive
(x,y) gas detector telescopes with Bragg-ionisation chambers(BRS). The BRS
gives the opportunity to measure the reaction angles in- and out-of-plane,
and through Bragg-curve spectroscopy to achieve a complete identification of
the nuclear charge for different final channels. We observed very narrow
out-of-plane angular correlations for two heavy fragments emitted in either
purely binary events or in events with a missing mass consisting of 2 and
3α-particles. These narrow correlations are interpreted as ternary
fission decay from compound nuclei at high angular momenta through an
elongated (hyper-deformed)
shape with very large moment of inertia. In these stretched configurations the
lighter mass in the neck region remains at rest or with very low momentum in
the center of mass.
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