The γ decay of the Giant Dipole Resonance in 132Ce nuclei has been measured in the compound temperature range 2.5 - 4.1 MeV using a symmetric reaction 64Ni (300, 400, 500 MeV) + 68Zn and an asymmetric one 16O (130, 250 MeV) + 116Sn. Both cases produce 132Ce compound nuclei at the same excitation energy and angular momentum. Light charged particles and evaporation residues have been measured in coincidence with high energy γ-rays. The data show that pre-equilibrium emission is present only in the asymmetric reaction while only statistical emission from a fully equilibrated 132Ce compound is present in the symmetric one. The measured Giant Dipole Resonance widths show an almost linear increase with the effective temperature. Such a measured trend is reproduced by the thermal fluctuation model which includes the lifetime of the compound nucleus. The comparison between the high energy γ-ray spectra in the symmetric and asymmetric reactions shows a dynamic dipole emission in the 16O-induced reaction. The yield is consistent with what has been previously measured in the same mass and energy range.
Progress in the study of the gamma decay of the giant dipole resonance in very hot rotating nuclei / A. Bracco, F. Camera. - In: NUCLEAR PHYSICS. A. - ISSN 0375-9474. - 788:1-4(2007), pp. 205-214.
Progress in the study of the gamma decay of the giant dipole resonance in very hot rotating nuclei
A. BraccoPrimo
;F. CameraUltimo
2007
Abstract
The γ decay of the Giant Dipole Resonance in 132Ce nuclei has been measured in the compound temperature range 2.5 - 4.1 MeV using a symmetric reaction 64Ni (300, 400, 500 MeV) + 68Zn and an asymmetric one 16O (130, 250 MeV) + 116Sn. Both cases produce 132Ce compound nuclei at the same excitation energy and angular momentum. Light charged particles and evaporation residues have been measured in coincidence with high energy γ-rays. The data show that pre-equilibrium emission is present only in the asymmetric reaction while only statistical emission from a fully equilibrated 132Ce compound is present in the symmetric one. The measured Giant Dipole Resonance widths show an almost linear increase with the effective temperature. Such a measured trend is reproduced by the thermal fluctuation model which includes the lifetime of the compound nucleus. The comparison between the high energy γ-ray spectra in the symmetric and asymmetric reactions shows a dynamic dipole emission in the 16O-induced reaction. The yield is consistent with what has been previously measured in the same mass and energy range.Pubblicazioni consigliate
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