| 1. |
- Herskind, B., et al.
(author)
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Light charged particles as gateway to hyperdeformation
- 2007
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In: Acta Physica Polonica B. - 0587-4254 .- 1509-5770. ; 38:4, s. 1421-1430
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Journal article (peer-reviewed)abstract
- The Euroball-IV gamma-detector array, equipped with the ancillary charged particle detector array DIAMANT was used to study the residues of the fusion reaction Ni-64 + Ni-64 double right arrow Ba-128 at E-beam. = 255 and 261 MeV, in an attempt to reach the highest angular momentum and verify the existence of predicted hyperdeformed rotational bands. No discrete hyperdeformed bands were identified, but nevertheless a breakthrough was obtained through a systematic search for rotational ridge structures with very large moments of inertia J(2) >= 100 h(2) MeV((-1)), in agreement with theoretical predictions for hyperdeformed shapes. Evidence for hyperdeformation was obtained by charged particle + gamma-ray gating, selecting triple correlated ridge structures in the continuum of each of the nuclei, Te-118, Xe-124 and Cs-124,Cs-125. In 7 additional nuclei, rotational ridges were also identified with J(2) = 71-77h(2) MeV((-1)), which most probably correspond to superdeformed shape. The angular distributions of the emitted charged particles show an excess in forward direction over expectations from pure compound evaporation, which may indicate that in-complete fusion plays an important role in the population of very elongated shapes.
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| 2. |
- Herskind, B., et al.
(author)
-
Charged particle feeding of hyperdeformed nuclei in the A=118-126 region
- 2006
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In: Physica Scripta. - 0031-8949 .- 1402-4896. ; T125, s. 108-114
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Journal article (peer-reviewed)abstract
- A breakthrough was recently obtained in the analysis of the so-called Hyper-Long-HyperDeformed (HLHD) experiment made at the EUROBALL-IV gamma-detector array (EB). The Ni-64 + Ni-64 double right arrow Ba-128* fusion reaction was studied at E-beam = 255 and 261 MeV, reaching the highest angular momentum that the compound nuclei can accommodate. To date no discrete HD rotational bands have been identified. However, rotational patterns in the form of ridge-structures in three-dimensional (3D) rotational mapped spectra are identified with dynamic moments of inertia J((2)) ranging from 71 to 111h(2) MeV-1 in 12 different nuclei selected by charged particle- and/or gamma-gating. The four nuclei, Te-118, Cs-124, Cs-125 and Xe-124 found with moment of inertia J((2)) >= 100h(2) MeV-1, are most likely hyperdeformed, the remaining nuclei with smaller values of J((2)), are considered to be superdeformed, in qualitative agreement with recent theoretical calculations.
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