669 research outputs found

    The absorbed energy in the Shroud body image formation appears as contributed by discrete values

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    Starting from the optical density distribution in the Shroud body image and without any assumption on the mechanism that acts at a distance, we deduce that the absorbed energy by the Linen of Turin, related to the human body shape presence, is due to the contribution of discrete energy values

    Main restrictions in the synthesis of new superheavy elements: quasifission or/and fusion-fission

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    The synthesis of superheavy elements stimulates the effort to study the peculiarities of the complete fusion with massive nuclei and to improve theoretical models in order to extract knowledge about reaction mechanism in heavy ion collisions at low energies. We compare the theoretical results of the compound nucleus (CN) formation and evaporation residue (ER) cross sections obtained for the 48^{48}Ca+248^{248}Cm and 58^{58}Fe+232^{232}Th reactions leading to the formation of the isotopes A=296 and A=290, respectively, of the new superheavy element Lv (Z=116). The ER cross sections, which can be measured directly, are determined by the complete fusion and survival probabilities of the heated and rotating compound nucleus. That probabilities can not be measured unambiguously but the knowledge about them is important to study the formation mechanism of the observed products. For this aim, the 48^{48}Ca+249^{249}Cf and 64^{64}Ni+232^{232}Th reactions have been considered too. The use of the mass values of superheavy nuclei calculated in the framework of the macroscopic-microscopic model by Warsaw group leads to smaller ER cross section for all of the reactions (excluding the 64^{64}Ni+232^{232}Th reaction) in comparison with the case of using the masses calculated by Peter M\"oller {\it et al}.Comment: 26 pages and 15 figures. arXiv admin note: text overlap with arXiv:1109.201

    Peculiarities of Nuclear Fusion in Synthesis of Superheavy Elements

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    The small probabilities of synthesis of new superheavy elements at GSI (Darmstadt, Germany), Joint Institute for Nuclear Research (Dubna, Russia), and RIKEN (Wako, Japan) during the last decade stimulate the experimental and theoretical studies of the nuclear reaction mechanism. 1– 4 In preparation of these experiments, the main aim is to reach maximum cross sections of the yield of evaporation residues (ER) as a result of the de-excitation of the heated compound nucleus which is formed in complete fusion of the projectile and target nuclei. Because the ER excitation function in the synthesis of superheavy elements has very narrow width for "cold fusion" reactions (5–10 MeV) with 208 Pb and 209 Bi targets 5 and the width of the "hot fusion" reactions with 48 Ca projectile on actinide ta

    Bremsstrahlung emission during α\alpha-decay of 226Ra^{226}{\rm Ra}

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    We obtained the spectrum of probability of the bremsstrahlung emission accompanying the α\alpha-decay of 226Ra^{226}{\rm Ra} (Eα_{\alpha}=4.8 MeV) by measuring the α\alpha-γ\gamma coincidences and using the model presented in our previous study on the α\alpha-decay of 214Po^{214}{\rm Po} (Eα_{\alpha}=7.7 MeV). We compare the experimental data with the quantum mechanical calculation and find a good agreement between theory and experiment. We discuss the differences between the photon spectra connected with the α\alpha-decay of the 226Ra^{226}{\rm Ra} and 214Po^{214}{\rm Po} nuclei. For the two mentioned nuclei we analyze the bremsstrahlung emission contributions from the tunneling and external regions of the nucleus barrier into the total spectrum, and we find the destructive interference between these contributions. We also find that the emission of photons during tunneling of the α\alpha-particle gives an important contribution to the bremsstrahlung spectrum in the whole Eγ_{\gamma} energy range of the studied 226^{226}Ra nucleus
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