WorldWideScience

Sample records for hot superheavy nuclei

  1. Superheavy nuclei

    CERN Document Server

    Sáro, S

    2003-01-01

    Experiments leading to transuranium and far transuranium nuclei as far as element 106 (seaborgium) are described. Physical knowledge derived from experimental data at this stage of complete synthesis nuclear reactions since the 1980s is analyzed. The effect of the shell structure on the stability of the nuclei, the extra-push effect, and the effect of isospin are discussed. Experiments leading to the synthesis of nuclei with Z = 107 - 112 by cold fusion are also described, as are hot fusion reactions resulting in superheavy nuclei Z = 114, 116 where, however, confirmation is only pending. Current state of the art in this area is also highlighted

  2. Synthesis and decay process of superheavy nuclei with Z=119-122 via hot-fusion reactions

    Energy Technology Data Exchange (ETDEWEB)

    Ghahramany, N.; Ansari, A. [Shiraz University, Department of Physics and Biruni Observatory, College of Science, Shiraz (Iran, Islamic Republic of)

    2016-09-15

    In this research article attempts have been made to calculate the superheavy-nuclei synthesis characteristics including, the potential energy parameters, fusion probability, fusion and evaporation residue (ER) cross sections as well as, decay properties of compound nucleus and the residue nuclei formation probability for elements with Z=119-122 by using the hot-fusion reactions. It is concluded that, although a selection of double magic projectiles such as {sup 48}Ca with high binding energy, simplifies the calculations significantly due to spherical symmetric shape of the projectile, resulting in high evaporation residue cross section, unfortunately, nuclei with Z > 98 do not exist in quantities sufficient for constructing targets for the hot-fusion reactions. Therefore, practically our selection is fusion reactions with titanium projectile because the mass production of target nuclei for experimental purposes is more feasible. Based upon our findings, it is necessary, for new superheavy-nuclei production with Z > 119, to use neutron-rich projectiles and target nuclei. Finally, the maximal evaporation residue cross sections for the synthesis of superheavy elements with Z=119-122 have been calculated and compared with the previously founded ones in the literature. (orig.)

  3. Synthesis and decay process of superheavy nuclei with Z=119-122 via hot-fusion reactions

    Science.gov (United States)

    Ghahramany, N.; Ansari, A.

    2016-09-01

    In this research article attempts have been made to calculate the superheavy-nuclei synthesis characteristics including, the potential energy parameters, fusion probability, fusion and evaporation residue (ER) cross sections as well as, decay properties of compound nucleus and the residue nuclei formation probability for elements with Z=119-122 by using the hot-fusion reactions. It is concluded that, although a selection of double magic projectiles such as 48Ca with high binding energy, simplifies the calculations significantly due to spherical symmetric shape of the projectile, resulting in high evaporation residue cross section, unfortunately, nuclei with Z > 98 do not exist in quantities sufficient for constructing targets for the hot-fusion reactions. Therefore, practically our selection is fusion reactions with titanium projectile because the mass production of target nuclei for experimental purposes is more feasible. Based upon our findings, it is necessary, for new superheavy-nuclei production with Z > 119, to use neutron-rich projectiles and target nuclei. Finally, the maximal evaporation residue cross sections for the synthesis of superheavy elements with Z=119-122 have been calculated and compared with the previously founded ones in the literature.

  4. Synthesis of superheavy nuclei with 238U target

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The production of superheavy nuclei with Z=108-116 via hot fusion reactions of the neutron-rich projectiles with 238U target is systematically studied.The results show that the production cross sections of superheavy nuclei do not decrease monotonously as the atomic number Z increasing.The cross sections of the superheavy nuclei at Z = 112 and 115 are enhanced as compared with the whole Z-trend in synthesis of the superheavy nuclei,which clearly illustrates that the reactions with large negative Q-value and shell correction are more favorable to synthesize superheavy nuclei.

  5. Synthesis of superheavy nuclei with 238U target

    Institute of Scientific and Technical Information of China (English)

    LIU ZuHua; BAO JingDong

    2009-01-01

    The production of superheavy nuclei with Z=108-116 via hot fusion reactions of the neutron-rich projectiles with 238u target is systematically studied.The results show that the production cross sections of superheavy nuclei do not decrease monotonously as the atomic number Z increasing.The cross sections of the superheavy nuclei at Z=112 and 115 are enhanced as compared with the whole Z-trend in synthesis of the superheavy nuclei,which clearly illustrates that the reactions with large negative Q-value and shell correction are more favorable to synthesize superheavy nuclei.

  6. Synthesis of superheavy nuclei: Obstacles and opportunities

    Directory of Open Access Journals (Sweden)

    Zagrebaev V.I.

    2015-01-01

    Full Text Available There are only 3 methods for the production of heavy and superheavy (SH nuclei, namely, fusion reactions, a sequence of neutron capture and beta(- decay and multinucleon transfer reactions. Low values of the fusion cross sections and very short half-lives of nuclei with Z<120 put obstacles in synthesis of new elements. At the same time, an important area of SH isotopes located between those produced in the cold and hot fusion reactions remains unstudied yet. This gap could be filled in fusion reactions of 48Ca with available lighter isotopes of Pu, Am, and Cm. New neutron-enriched isotopes of SH elements may be produced with the use of a 48Ca beam if a 250Cm target would be prepared. In this case we get a real chance to reach the island of stability owing to a possible beta(+ decay of 291114 and 287112 nuclei formed in this reaction with a cross section of about 0.8 pb. A macroscopic amount of the long-living SH nuclei located at the island of stability may be produced by using the pulsed nuclear reactors of the next generation only if the neutron fluence per pulse will be increased by about three orders of magnitude. Multinucleon transfer processes look quite promising for the production and study of neutron-rich heavy nuclei located in upper part of the nuclear map not reachable by other reaction mechanisms. Reactions with actinide beams and targets are of special interest for synthesis of new neutron-enriched transfermium nuclei and not-yet-known nuclei with closed neutron shell N=126 having the largest impact on the astrophysical r-process. The estimated cross sections for the production of these nuclei allows one to plan such experiments at currently available accelerators.

  7. Doubly magic properties in superheavy nuclei

    Institute of Scientific and Technical Information of China (English)

    HUANG Ya-Wei; ZHU Jian-Yu

    2009-01-01

    A systematic study of global properties of superheavy nuclei in the framework of the Liquid Drop Model and the Strutinsky shell correction method is performed. The evolution equilibrium deformations, TRS graphs and α-decay energies are calculated using the TRS model. The analysis covers a wide range of even-even superheavy nuclei from Z = 102 to 122. Magic numbers and their observable influence occurring in this region have been investigated. Shell closures appear at proton number Z = 114 and at neutron number N = 184.

  8. Superheavy nuclei – cold synthesis and structure

    Indian Academy of Sciences (India)

    Raj K Gupta

    2001-08-01

    The quantum mechanical fragmentation theory (QMFT), given for the cold synthesis of new and superheavy elements, is reviewed and the use of radioactive nuclear beams (RNB) and targets (RNT) is discussed. The QMFT is a complete theory of cold nuclear phenomena, namely, the cold fission, cold fusion and cluster radioactivity. Also, the structure calculations based on the axially deformed relativistic mean field (DRMF) approach are presented which predict new regions of spherical magicity, namely = 120 and = 172 or 184, for superheavy nuclei. This result is discussed in the light of recent experiments reporting the cold synthesis of = 118 element.

  9. From heavy nuclei to super-heavy nuclei

    CERN Document Server

    Theisen, C

    2003-01-01

    The existence of super-heavy nuclei has been predicted nearly fifty years ago. Due to the strong coulomb repulsion, the stabilisation of these nuclei is possible only through shell effects. The reasons for this fragile stability, as well as the theoretical predictions concerning the position of the island of stability are presented in the first part of this lecture. In the second part, experiments and experimental techniques which have been used to synthesize or search for super-heavy elements are described. Spectroscopic studies performed in very heavy elements are presented in the following section. We close this lecture with techniques that are currently being developed in order to reach the superheavy island and to study the structure of very-heavy nuclei.

  10. Decay of heavy and superheavy nuclei

    Indian Academy of Sciences (India)

    K P Santhosh

    2014-04-01

    We present here, an overview and progress of the theoretical works on the isomeric state decay, decay fine structure of even–even, even–odd, odd–even and odd–odd nuclei, a study on the feasibility of observing decay chains from the isotopes of the superheavy nuclei = 115 in the range 271 ≤ ≤ 294 and the isotopes of = 117 in the range 270 ≤ ≤ 301, within the Coulomb and proximity potential model for deformed nuclei (CPPMDN). The computed half-lives of the favoured and unfavoured decay of nuclei in the range 67 ≤ ≤ 91 from both the ground state and isomeric state, are in good agreement with the experimental data and the standard deviation of half-life is found to be 0.44. From the fine structure studies done on various ranges of nuclei, it is evident that, for nearly all the transitions, the theoretical values show good match with the experimental values. This reveals that CPPMDN is successful in explaining the fine structure of even–even, even–odd, odd–even and odd–odd nuclei. Our studies on the decay of the superheavy nuclei 271−294115 and 270−301117 predict 4 chains consistently from 284,285,286115 nuclei and 5 chains and 3 chains consistently from 288−291117 and 292117, respectively. We thus hope that these studies on 284−286115 and 288−292117 will be a guide to future experiments.

  11. Alpha decay chains from superheavy nuclei

    CERN Document Server

    Samanta, C

    2008-01-01

    Magic islands for extra-stable nuclei in the midst of the sea of fission-instability were predicted to be around Z=114, 124 or, 126 with N=184, and Z=120, with N=172. Whether these fission-survived superheavy nuclei with high Z and N would live long enough for detection or, undergo alpha-decay in a very short time remains an open question. Alpha-decay half lives of nuclei with 130 118 are found to have alpha-decay half lives of the order of microseconds or, less.

  12. Spontaneous fission of superheavy nuclei

    Indian Academy of Sciences (India)

    R A Gherghescu; D N Poenaru

    2015-09-01

    The macroscopic–microscopic method is extended to calculate the deformation energy and penetrability for binary nuclear configurations typical for fission processes. The deformed two-centre shell model is used to obtain single-particle energy levels for the transition region of two partially overlapped daughter and emitted fragment nuclei. The macroscopic part is obtained using the Yukawa-plus-exponential potential. The microscopic shell and pairing corrections are obtained using the Strutinsky and BCS approaches and the cranking formulae yield the inertia tensor. Finally, the WKB method is used to calculate penetrabilities and spontaneous fission half-lives. Calculations are performed for the decay of 282,292120 nuclei.

  13. Superheavy nuclei: from predictions to discovery

    Science.gov (United States)

    Oganessian, Yu Ts; Sobiczewski, A.; Ter-Akopian, G. M.

    2017-02-01

    A fundamental outcome of modern nuclear microscopic theory is the prediction of the ‘islands of stability’ in the region of hypothetical superheavy elements (SHEs). In a heavy nucleus, going through the large-scale deformation on the way to fission, the motion of single nucleons is coupled with the collective degrees of freedom of the whole system. The most striking effect of this coupling is obtained for the case of fission of the heaviest nuclei, whose existence is defined entirely by the nuclear structure, i.e. by the shell effect. From this point of view, the synthesis and study of properties of superheavy nuclei (SHN) is a direct way for checking the basic statements of the microscopic nuclear theory. On the nuclide map, SHN outline the border of the heaviest nuclear masses. SHN set the limits of the periodic system of chemical elements. The study of possible existence of SHN in nature offers a way for testing different scenarios of astrophysical nucleosynthesis. The paper elucidates experimental approaches, used for testing the theory predictions made about the SHN, and presents the results of the discovery of the ‘stability island’ of SHEs.

  14. Population of rotational bands in superheavy nuclei

    Directory of Open Access Journals (Sweden)

    Antonenko N.V.

    2012-02-01

    Full Text Available Using the statistical approach, we study the population of ground-state rotational bands of superheavy nuclei produced in the fusion-evaporation reactions 208Pb(48Ca, 2n254No, 206Pb(48Ca, 2n252No, and 204Hg(48Ca, 2n250Fm. We calculate relative intensities of E2-transitions between the rotational states and entry spin distributions of the residual nuclei, evaporation residue cross sections, and excitation functions for these reactions. Fermi-gas model is used for the calculation of level density, and damping of shell effects both with excitation energy and angular momentum is taking into account. The results are in a good agreement with the experiment data.

  15. Adiabatic fission barriers in superheavy nuclei

    CERN Document Server

    Jachimowicz, P; Skalski, J

    2016-01-01

    Using the microscopic-macroscopic model based on the deformed Woods-Saxon single-particle potential and the Yukawa-plus-exponential macroscopic energy we calculated static fission barriers $B_{f}$ for 1305 heavy and superheavy nuclei $98\\leq Z \\leq 126$, including even - even, odd - even, even - odd and odd - odd systems. For odd and odd-odd nuclei, adiabatic potential energy surfaces were calculated by a minimization over configurations with one blocked neutron or/and proton on a level from the 10-th below to the 10-th above the Fermi level. The parameters of the model that have been fixed previously by a fit to masses of even-even heavy nuclei were kept unchanged. A search for saddle points has been performed by the "Imaginary Water Flow" method on a basic five-dimensional deformation grid, including triaxiality. Two auxiliary grids were used for checking the effects of the mass asymmetry and hexadecapole non-axiallity. The ground states were found by energy minimization over configurations and deformations...

  16. Formation of superheavy nuclei in cold fusion reactions

    CERN Document Server

    Feng, Zhao-Qing; Li, Jun-Qing; Scheid, Werner

    2007-01-01

    Within the concept of the dinuclear system (DNS), a dynamical model is proposed for describing the formation of superheavy nuclei in complete fusion reactions by incorporating the coupling of the relative motion to the nucleon transfer process. The capture of two heavy colliding nuclei, the formation of the compound nucleus and the de-excitation process are calculated by using an empirical coupled channel model, solving a master equation numerically and applying statistical theory, respectively. Evaporation residue excitation functions in cold fusion reactions are investigated systematically and compared with available experimental data. Maximal production cross sections of superheavy nuclei in cold fusion reactions with stable neutron-rich projectiles are obtained. Isotopic trends in the production of the superheavy elements Z=110, 112, 114, 116, 118 and 120 are analyzed systematically. Optimal combinations and the corresponding excitation energies are proposed.

  17. Cluster decay analysis and related structure effects of fissionable heavy and superheavy nuclei

    Indian Academy of Sciences (India)

    Manoj K Sharma; Gurvinder Kaur

    2015-09-01

    Collective clusterization approach of dynamical cluster decay model (DCM) has been applied to study the attributes of hot ( ≠ 0) and rotating (ℓ = 0) nuclei lying in heavy and super-heavy mass regimes. We present here an overview of the characteristic fission decay properties such as shell effect, role of entrance channel, quadrupole (2) deformations and impact of hot (equatorial) compact orientation degree of freedom in comparison to cold (polar) elongated configuration. The presence of non-compound nucleus process, i.e., quasifission, is also investigated. Apart from studying the decay of excited state nuclei, the dynamics of heavy particle cluster emission is also addressed using the preformed cluster model (PCM).

  18. Probable Heavy Particle Decays from 306-339128 Superheavy Nuclei

    Science.gov (United States)

    Santhosh, K. P.; Sukumaran, Indu

    2016-12-01

    The heavy particle decays that are probable from the isotopes of Z = 128 superheavy nuclei within the range A = 306-339 have been analyzed within the Coulomb and proximity potential model (CPPM). The study includes the evaluation of heavy particle decay half-lives of 24 clusters, including both odd and even clusters that are supposed to be emitted from the Z = 128 superheavy nuclei. The predicted values in comparison with the models Universal curve (UNIV), Universal decay law (UDL), and scaling law of Horoi et al. are observed to follow the same trend, and almost all the values lie well within the experimental limit ( T 1/2 Geiger-Nuttall plots of log10( T 1/2) vs. Q -1/2 confirming the presence of shell closure effect and the plot of universal curve of log10( T 1 /2) vs.-lnP revealed the reliability of the model CPPM.

  19. Formation of Superheavy Nuclei in Massive Fusion Reactions

    Institute of Scientific and Technical Information of China (English)

    FENG Zhao-qing; JIN Gen-ming; LI Jun-qing; Scheid Werner

    2009-01-01

    Within the concept of the dinuclear system(DNS),by incorporating the coupling of the relative motion to the nucleon transfer process,a dynamical model is proposed for describing the formation of superheavy residue nucleus in massive fusion reactions,in which the capture of two heavy colliding nuclei,the formation of compound nucleus and the de-excitation process are calculated using empirical coupled channel model,solving master equation numerically and statistical theory,respectively.By using the DNS model,the evaporation-residue excitation functions in the ~(48)Ca induced fusion reactions and in the cold fusion reactions are investigated systematically and compared with available experimental data.Optimal evaporation channels and combinations as well as the corresponding excitation energies are proposed.The possible factors that influencing the isotopic dependence of the production cross sections are analyzed.The formation of the superheavy nuclei based on the isotopes U with different projectiles are also investigated.

  20. Influence of hexadecapole deformation on production cross sections of superheavy nuclei

    Science.gov (United States)

    Bao, X. J.; Guo, S. Q.; Zhang, H. F.; Li, J. Q.

    2016-12-01

    The current heaviest superheavy nuclei (SHN) are experimentally synthesized by using 48Ca to bombard actinide nuclei via fusion reactions. Actinide nuclei often have considerable hexadecapole deformation in addition to quadrupole deformation, which was not considered in previous theoretical studies. With the dinuclear system concept, and by taking the hexadecapole deformation in to consideration in addition to the quadrupole deformation, the hot fusion probability leading to the synthesis of SHN is investigated systematically. Synthesis of superheavy elements 296118 and 295118 by using the 48Ca+251Cf reaction channel is evaluated and discussed, and the maximal evaporation residue cross sections (ERCSs) of the 3n and 4n channels are predicted to be 1.90 and 0.11 pb, respectively. The predicted maximum ERCSs in 3n and 4n evaporation channels of the 249Bk(50Ti,xn){}299-x119 reaction are 0.12 and 0.04 pb, respectively. The most favorable reaction to synthesize the element Z = 120 turns out to be 251Cf(50Ti,xn){}301-x120, but the predicted maximum cross section for this reaction is only 67 fb. Therefore, superheavy element 119 may be the most hopeful new element for Z\\gt 118 to be synthesized under some improved experimental conditions in the near future.

  1. From heavy nuclei to super-heavy nuclei; Des noyaux lourds aux super-lourds

    Energy Technology Data Exchange (ETDEWEB)

    Theisen, Ch

    2003-01-01

    The existence of super-heavy nuclei has been predicted nearly fifty years ago. Due to the strong coulomb repulsion, the stabilisation of these nuclei is possible only through shell effects. The reasons for this fragile stability, as well as the theoretical predictions concerning the position of the island of stability are presented in the first part of this lecture. In the second part, experiments and experimental techniques which have been used to synthesize or search for super-heavy elements are described. Spectroscopic studies performed in very heavy elements are presented in the following section. We close this lecture with techniques that are currently being developed in order to reach the superheavy island and to study the structure of very-heavy nuclei. (author)

  2. Probable cluster decays from $^{270-318}$118 superheavy nuclei

    CERN Document Server

    Santhosh, K P

    2014-01-01

    The cluster decay process in $^{270-318}$118 superheavy nuclei has been studied extensively within the Coulomb and proximity potential model (CPPM), thereby investigating the probable cluster decays from the various isotopes of $Z = 118$. On comparing the predicted decay half lives with the values evaluated using the Universal formula for cluster decay (UNIV) of Poenaru et al., the Universal Decay Law (UDL) of Qi et al., and the Scaling Law of Horoi et al., it was seen that, our values matches well with these theoretical values. A comparison of the predicted alpha decay half life of the experimentally synthesized superheavy isotope $^{294}$118 with its corresponding experimental value shows that, our theoretical value is in good agreement with the experimental value. The plots for $log_{10}(T_{1/2})$ against the neutron number of the daughter in the corresponding decay reveals the behavior of the cluster half lives with the neutron number of the daughter nuclei and for most of the decays, the half life was fo...

  3. Half-life predictions for decay modes of superheavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Duarte, S.B.; Tavares, O.A.P. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Goncalves, M. [Instituto de Radioprotecao e Dosimetria (IRD), Rio de Janeiro, RJ (Brazil); Rodriguez, O.; Guzman, F. [Instituto Superior de Ciencias e Tecnologia Nucleares (InSTEC), La Habana (Cuba); Barbosa, T.N.; Garcia, F.; Dimarco, A. [Universidade Estadual de Santa Cruz, Ilheus, BA (Brazil). Dept. de Ciencias Exatas e Tecnologicas

    2004-09-01

    We applied the Effective Liquid Drop Model (ELDM) to predict the alpha-decay, cluster emission and cold fission half-life-values of nuclei in the region of Superheavy Elements (SHE). The present calculations have been made in the region of the ZN-plane defined by 155 <=N <=220 and 110<=Z<=135. Shell effects are included via the Q-value of the corresponding decay case. We report the results of a systematic calculation of the half-life for the three nuclear decay modes in a region of the ZN-plane where superheavy elements are expected to be found. Results have shown that, among the decay modes investigated here, the alpha decay is the dominant one. i.e, the decay mode of smallest half-lives. Half-life predictions for alpha decay, cluster emission and cold fission for the isotopic family of the most recent SHE detected of Z=115 and for the isotopic family of the already consolidated SHE of Z=111 are presented. (author)

  4. Fission of super-heavy nuclei explored with Skyrme forces

    CERN Document Server

    Schindzielorz, N; Klüpfel, P; Reinhard, P -G; Hager, G

    2010-01-01

    We present a large scale survey of life-times for spontaneous fission in the regime of super-heavy elements (SHE), i.e. nuclei with Z=104-122. This is done on the basis of the Skyrme-Hartree-Fock model. The axially symmetric fission path is computed using a quadrupole constraint. Self-consistent cranking is used for the collective masses and associated quantum corrections. The actual tunneling probability is estimated by the WKB approximation. Three typical Skyrme forces are used to explore the sensitivity of the results. Benchmarks in the regime Z=104-108 show an acceptable agreement. The general systematics reflects nicely the islands of shell stabilization and the crossover from $\\alpha$-decay to fission for the decay chains from the region of Z/N=118/176.

  5. Remarks on the fission barriers of super-heavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, S. [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Goethe-Universitaet Frankfurt, Institut fuer Physik, Frankfurt (Germany); Heinz, S.; Mann, R.; Maurer, J.; Muenzenberg, G.; Barth, W.; Dahl, L.; Kindler, B.; Kojouharov, I.; Lang, R.; Lommel, B.; Runke, J.; Scheidenberger, C.; Tinschert, K. [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Antalic, S. [Comenius University, Department of Nuclear Physics and Biophysics, Bratislava (Slovakia); Eberhardt, K.; Thoerle-Pospiech, P.; Trautmann, N. [Johannes Gutenberg-Universitaet Mainz, Mainz (Germany); Grzywacz, R. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); University of Tennessee, Knoxville, TN (United States); Hamilton, J.H. [Vanderbilt University, Department of Physics and Astronomy, Nashville, TN (United States); Henderson, R.A.; Kenneally, J.M.; Moody, K.J.; Shaughnessy, D.A.; Stoyer, M.A. [Lawrence Livermore National Laboratory, Livermore, CA (United States); Miernik, K. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); University of Warsaw, Warsaw (Poland); Miller, D. [University of Tennessee, Knoxville, TN (United States); Morita, K. [RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama (Japan); Nishio, K. [Japan Atomic Energy Agency, Tokai, Ibaraki (Japan); Popeko, A.G.; Yeremin, A.V. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Roberto, J.B.; Rykaczewski, K.P. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Uusitalo, J. [University of Jyvaeskylae, Department of Physics, Jyvaeskylae (Finland)

    2016-04-15

    Shell-correction energies of super-heavy nuclei are approximated by using Q{sub α} values of measured decay chains. Five decay chains were analyzed, which start at the isotopes {sup 285}Fl, {sup 294}118, {sup 291}Lv, {sup 292}Lv and {sup 293}Lv. The data are compared with predictions of macroscopic-microscopic models. Fission barriers are estimated that can be used to eliminate uncertainties in partial fission half-lives and in calculations of evaporation-residue cross-sections. In that calculations, fission probability of the compound nucleus is a major factor contributing to the total cross-section. The data also provide constraints on the cross-sections of capture and quasi-fission in the entrance channel of the fusion reaction. Arguments are presented that fusion reactions for synthesis of isotopes of elements 118 and 120 may have higher cross-sections than assumed so far. (orig.)

  6. Systematic study of survival probability of excited superheavy nuclei

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The stability of excited superheavy nuclei (SHN) with 100 Z 134 against neutron emission and fission is investigated by using a statistical model. In particular, a systematic study of the survival probability against fission in the 1n-channel of these SHN is made. The present calculations consistently take the neutron separation energies and shell correction energies from the calculated results of the finite range droplet model which predicts an island of stability of SHN around Z = 115 and N = 179. It turns out that this island of stability persists for excited SHN in the sense that the calculated survival probabilities in the 1n-channel of excited SHN at the optimal excitation energy are maximized around Z = 115 and N = 179. This indicates that the survival probability in the 1n-channel is mainly determined by the nuclear shell effects.

  7. Possibilities of synthesis of unknown isotopes of superheavy nuclei with charge numbers Z > 108 in asymmetric actinide-based complete fusion reactions

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Juhee [Institute for Basic Science, Rare Isotope Science Project, Daejeon (Korea, Republic of); Adamian, G.G. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Antonenko, N.V. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Tomsk Polytechnic University, Mathematical Physics Department, Tomsk (Russian Federation)

    2016-10-15

    The possibilities of production of new isotopes of superheavy nuclei with charge numbers Z = 109-114 in various asymmetric hot fusion reactions are studied for the first time. The excitation functions of the formation of these isotopes in the xn evaporation channels are predicted and the optimal conditions for the synthesis are proposed. The products of the suggested reactions can fill a gap of unknown isotopes between the isotopes of the heaviest nuclei obtained in cold and hot complete fusion reactions. (orig.)

  8. Possibilities of synthesis of unknown isotopes of superheavy nuclei with charge numbers Z > 108 in asymmetric actinide-based complete fusion reactions

    Science.gov (United States)

    Hong, Juhee; Adamian, G. G.; Antonenko, N. V.

    2016-10-01

    The possibilities of production of new isotopes of superheavy nuclei with charge numbers Z = 109-114 in various asymmetric hot fusion reactions are studied for the first time. The excitation functions of the formation of these isotopes in the xn evaporation channels are predicted and the optimal conditions for the synthesis are proposed. The products of the suggested reactions can fill a gap of unknown isotopes between the isotopes of the heaviest nuclei obtained in cold and hot complete fusion reactions.

  9. Ground State Properties of Superheavy Nuclei in Macroscopic-Microscopic Model

    Institute of Scientific and Technical Information of China (English)

    ZHI Qi-Jun; REN Zhong-Zhou; ZHANG Xiao-Ping; ZHENG Qiang

    2008-01-01

    The ground state properties of superheavy nuclei are systematically calculated by the macroscopic-microscopic (MM) model with the Nilsson potential The calculations well produced the ground state binding energies,a-decay energies,and half lives of superheavy nuclei.The calculated results are systematically compared with available experimental data.The calculated results are also compared with theoretical results from other MM models and from relativistic mean-field model.The calculations and comparisons show that the MM model is reliable in superheavy region and that the MM model results are not very sensitive to the choice of microscopic single-particle potential.

  10. Shell Effect of Superheavy Nuclei in Self-consistent Mean-Field Models

    Institute of Scientific and Technical Information of China (English)

    RENZhong-Zhou; TAIFei; XUChang; CHENDing-Han; ZHANGHu-Yong; CAIXiang-Zhou; SHENWen-Qing

    2004-01-01

    We analyze in detail the numerical results of superheavy nuclei in deformed relativistic mean-field model and deformed Skyrme-Hartree-Fock model. The common points and differences of both models are systematically compared and discussed. Their consequences on the stability of superheavy nuclei are explored and explained. The theoreticalresults are compared with new data of superheavy nuclei from GSI and from Dubna and reasonable agreement is reached.Nuclear shell effect in superheavy region is analyzed and discussed. The spherical shell effect disappears in some cases due to the appearance of deformation or superdeformation in the ground states of nuclei, where valence nucleons occupysignificantly the intruder levels of nuclei. It is shown for the first time that the significant occupation of vaJence nucleons on the intruder states plays an important role for the ground state properties of superheavy nuclei. Nuclei are stable in the deformed or superdeformed configurations. We further point out that one cannot obtain the octupole deformation of even-even nuclei in the present relativistic mean-field model with the σ,ω and ρ mesons because there is no parityviolating interaction and the conservation of parity of even-even nuclei is a basic assumption of the present relativistic mean-field model.

  11. Statistical Behaviors of Quantum Spectra in Superheavy Nuclei

    Institute of Scientific and Technical Information of China (English)

    WUXi-zhen; LIZhu-xia; WANGNing

    2003-01-01

    Recently, the statistical features of spectra for the deformed space explored by the fission have been studied and a new insight into fission and hyperdeformation has been given. The extension of this kind of investigations to superheavy nuclear systems is a very valuable. In this paper we study the nearest neighbor level-spacing distributions of superheavy systems based on mean field models.

  12. Influence of proton shell closure on the evaporation residue cross sections of superheavy nuclei

    Science.gov (United States)

    Bao, X. J.; Guo, S. Q.; Zhang, H. F.; Li, J. Q.

    2017-04-01

    Within the dinuclear system model we systematically calculate the evaporation residue cross sections (ERCSs) of superheavy nuclei (SHN) for the 48Ca-induced hot fusion reactions. Different calculations of the fission barriers of the SHN are used. The difference is as large as two orders of magnitude of ERCSs by applying the various fission barriers for the reaction 48Ca+249Cf. The dependence of the calculated ERCSs on the predicted shell structure and magic numbers of the heavier SHN is discussed. It is found that the structure of SHN crucially influences the ERCSs. Measurement of ERCSs for at least one isotope of the Z > 118 nucleus would help us to set a proper shell model for the SHN with Z > 118.

  13. Alpha decay potential barriers and half-lives and analytical formula predictions for superheavy nuclei

    OpenAIRE

    Royer, G.; Zhang, H. F.

    2008-01-01

    International audience; The synthesis of superheavy elements has advanced strongly recently and their main observed decay mode is alpha emission. Predictions of alpha decay half-lives of other possible superheavy nuclei are needed. The alpha decay potential barrier is often described using a finite square well for the one-body shapes plus an hyperbola for the Coulomb repulsion between the alpha particle and its daughter. An arbitrary adjustment of the parameters allows to reproduce roughly th...

  14. Statistical Behavoirs of Quantum Spectra in Superheavy Nuclei

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    From the point of view of the interplay between order and chaos, the most regular single-particle motion of neutrons has been found in the superheavy system of Z=120 and N=184 based on the Skyrme-Hartree-Fock model and in the system of Z=120 and N=\\12 based on the relativistic mean-field model. It has been shown that the statistical analysis of spectra indeed can give very valuable information about the stability of superheavy systems. The significance of this kind of study can go far beyond the investigation on the stability of superheavy systems and it may give a deep

  15. Structure of exotic nuclei and superheavy elements in meson field theory

    Energy Technology Data Exchange (ETDEWEB)

    Linn, Khin Nyan

    2008-07-15

    In this work the nuclear structure of exotic nuclei and superheavy nuclei is studied in a relativistic framework. In the relativistic mean-field (RMF) approximation, the nucleons interact with each other through the exchange of various effective mesons (scalar, vector, isovector-vector). Ground state properties of exotic nuclei and superheavy nuclei are studied in the RMF theory with the three different parameter sets (ChiM,NL3,NL-Z2). Axial deformation of nuclei within two drip lines are performed with the parameter set (ChiM). The position of drip lines are investigated with three different parameter sets (ChiM,NL3,NL-Z2) and compared with the experimental drip line nuclei. In addition, the structure of hypernuclei are studied and for a certain isotope, hyperon halo nucleus is predicted. (orig.)

  16. Statistical Behaviors of Quantum Spectra in Superheavy Nuclei

    Institute of Scientific and Technical Information of China (English)

    WU Xi-Zhen; LI Zhu-Xia; WANG Ning; J.A. Maruhn

    2003-01-01

    From the point of view of the interplay between order and chaos, the most regular single-particle motion of neutrons has been found in the superheavy system with Z = 120 and N = 184 based on the Skyrme-Hartree-Fock model and in the system with Z = 120 and N = 172 based on the relativistic mean-field model. It has been shown that the statistical analysis of spectra can give valuable information about the stability of suprheavy systems. In addition it may yield deep insight into the single-particle motion in the mean field formed by the superheavy system.

  17. Searches for superheavy elements in nature: Cosmic-ray nuclei; spontaneous fission

    Energy Technology Data Exchange (ETDEWEB)

    Ter-Akopian, G.M., E-mail: gurgen@jinr.ru; Dmitriev, S.N.

    2015-12-15

    There is little chance that superheavy nuclei with lifetimes of no less than 100 million years are present on the stability island discovered at present. Also, pessimistic are the results of estimates made about their nucleosynthesis in r-process. Nevertheless, the search for these nuclei in nature is justified in view of the fundamental importance of this topic. The first statistically significant data set was obtained by the LDEF Ultra-Heavy Cosmic-Ray Experiment, consisting of 35 tracks of actinide nuclei in galactic cosmic rays. Because of their exceptionally long exposure time in Galaxy, olivine crystals extracted from meteorites generate interest as detectors providing unique data regarding the nuclear composition of ancient cosmic rays. The contemporary searches for superheavy elements in the earth matter rely on knowledge obtained from chemical studies of artificially synthesized superheavy nuclei. New results finding out the chemical behavior of superheavy elements should be employed to obtain samples enriched in their homologues. The detection of rare spontaneous fission events and the technique of accelerator mass spectrometry are employed in these experiments.

  18. Candidates for Long Lived High-K Ground States in Superheavy Nuclei

    CERN Document Server

    Jachimowicz, P; Skalski, J

    2015-01-01

    On the basis of systematic calculations for 1364 heavy and superheavy nuclei, including odd-systems, we have found a few candidates for high-K ground states in superheavy nuclei. The macroscopic-microscopic model based on the deformed Woods-Saxon single particle potential which we use offers a reasonable description of SH systems, including known: nuclear masses, $Q_{\\alpha}$-values, fission barriers, ground state deformations, super- and hyper-deformed minima in the heaviest nuclei. %For odd and odd-odd systems, both ways of including pairing correlations, % blocking and the quasi-particle method, have been applied. Exceptionally untypical high-K intruder contents of the g.s. found for some nuclei accompanied by a sizable excitation of the parent configuration in daughter suggest a dramatic hindrance of the $\\alpha$-decay. Multidimensional hyper-cube configuration - constrained calculations of the Potential Energy Surfaces (PES's) for one especially promising candidate, $^{272}$ Mt, shows a $\\backsimeq$ 6 Me...

  19. Odd-even Effect of Survival Probability for Superheavy Compound Nuclei

    Institute of Scientific and Technical Information of China (English)

    LiWenfei; XuHushan; MaYue; ZhangHongfei; ZuoWei; LiJunqing; WangNan; ZhaoEnguang; W.Scheid

    2003-01-01

    The survival probability of a compound nucleus measures the competition among the neutron evaporation, light charged particle emissions and fission in the process of its de-excitation. It is considered as one of the crucial factors for producing superheavy elements, which is usually described by the existing statistical models[1]. In spite of the well developed statistical theory itself, however, due to the unclearness of the structure of superheavy nuclei, some characteristic quantities for evaluating the fission and particle emission widths are correspondingly ambiguous. This report gives the study on the odd-even effects of the survival probability based on a statistical model. The calculation details can be found.

  20. Actinide Isotopes for the Synthesis of Superheavy Nuclei

    Science.gov (United States)

    Roberto, J. B.; Alexander, C. W.; Boll, R. A.; Dean, D. J.; Ezold, J. G.; Felker, L. K.; Rykaczewski, K. P.

    2014-09-01

    Recent research resulting in the synthesis of isotopes of new elements 113-118 has demonstrated the importance of actinide targets in superheavy element research. Oak Ridge National Laboratory (ORNL) has unique facilities for the production and processing of actinide target materials, including the High Flux Isotope Reactor (HFIR) and the Radiochemical Engineering Development Center (REDC). These facilities have provided actinide target materials that have been used for the synthesis of all superheavy (SHE) elements above Copernicium (element 112). In this paper, the use of actinide targets for SHE research and discovery is described, including recent results for element 117 using 249Bk target material from ORNL. ORNL actinide capabilities are reviewed, including production and separation/purification, availabilities of actinide materials, and future opportunities including novel target materials such as 251Cf.

  1. Monopole transitions in hot nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Sujkowski, Z. [Soltan Inst. for Nuclear Studies, Otwock-Swierk (Poland)

    1994-12-31

    Monopole transitions can be a signature of shape changing in a hot, pulsating nucleus (the low energy E0 mode) and/or a measure of the compressibility of finite nuclei (GMR, the breathing mode). Experimental information pertaining to GMR is reviewed. Recipes for deducing the incompressibility modules for infinite nuclear matter from data on GMR are discussed. Astrophysical implications are outlined. The first attempts at locating the GMR strength in moderately hot nuclei are described. Prospects for improving the experimental techniques to make an observation of this strength in selected nuclei unambiguous are discussed. (author). 46 refs, 8 figs.

  2. Macroscopic-microscopic calculations of ground state properties of superheavy nuclei

    Institute of Scientific and Technical Information of China (English)

    ZHI Qi-jun; Mao Ying-chen; REN Zhong-zhou

    2006-01-01

    We systematically calculate the ground state properties of superheavy even-even nuclei with proton number Z=94-118.The calculations are based on the liquid drop macroscopic model and the microscopic model with the modified single-particle oscillator potential. The calculated binding energies and α-decay energies agree well with the experimental data.The reliability of the macroscopic-microscopic(MM)model for superheavy nuclei is confirmed by the good agreement between calculated results and experimental ones. Detailed comparisons between our calculations and M(o)ller's are made.It is found that the calculated results also agree with M(o)ller's results and that the MM model is insensitive to the microscopic single-particle potential. Calculated results are also compared with results from relativistic mean-field (RMF)model and from Skyrme-Hatree-Fock(SHF) model.In addition,half-lives,deformations and shape coexistence are also investigated.The properties of some unknown nuclei are predicted and they will be useful for future experimental researches of superheavy nuclei.

  3. A Statistical Approach to Describe Highly Excited Heavy and Superheavy Nuclei

    CERN Document Server

    Chen, Peng-Hui; Li, Jun-Qing; Zhang, Hong-Fei

    2016-01-01

    A statistical approach based on the Weisskopf evaporation theory has been developed to describe the de-excitation process of highly excited heavy and superheavy nuclei, in particular for the proton-rich nuclei. The excited nucleus is cooled by evaporating $\\gamma$-ray, light particles (neutrons, protons, $\\alpha$ etc) in competition with the binary fission, in which the structure effects (shell correction, fission barrier, particle separation energy) contribute to the processes. The formation of residual nuclei is evaluated via sequential emission of possible particles above the separation energies. The available data of fusion-evaporation excitation functions in the $^{28}$Si+$^{198}$Pt reaction can be reproduced nicely well within the approach.

  4. Covariant density functional theory: Reexamining the structure of superheavy nuclei

    CERN Document Server

    Agbemava, S E; Nakatsukasa, T; Ring, P

    2015-01-01

    A systematic investigation of even-even superheavy elements in the region of proton numbers $100 \\leq Z \\leq 130$ and in the region of neutron numbers from the proton-drip line up to neutron number $N=196$ is presented. For this study we use five most up-to-date covariant energy density functionals of different types, with a non-linear meson coupling, with density dependent meson couplings, and with density-dependent zero-range interactions. Pairing correlations are treated within relativistic Hartree-Bogoliubov (RHB) theory based on an effective separable particle-particle interaction of finite range and deformation effects are taken into account. This allows us to assess the spread of theoretical predictions within the present covariant models for the binding energies, deformation parameters, shell structures and $\\alpha$-decay half-lives. Contrary to the previous studies in covariant density functional theory, it was found that the impact of $N=172$ spherical shell gap on the structure of superheavy elemen...

  5. Fusion-fission probabilities, cross sections, and structure notes of superheavy nuclei

    Science.gov (United States)

    Kowal, Michał; Cap, Tomasz; Jachimowicz, Piotr; Skalski, Janusz; Siwek-Wilczyńska, Krystyna; Wilczyński, Janusz

    2016-12-01

    Fusion - fission probabilities in the synthesis of heaviest elements are discussed in the context of the latest experimental reports. Cross sections for superheavy nuclei are evaluated using the "Fusion by Diffusion" (FBD) model. Predictive power of this approach is shown for experimentally known Lv and Og isotopes and predictions given for Z = 119, 120. Ground state and saddle point properties as masses, shell corrections, pairing energies, and deformations necessary for cross-section estimations are calculated systematically within the multidimensional microscopic-macroscopic method based on the deformed Woods-Saxon single-particle potential. In the frame of the FBD approach predictions for production of elements heavier than Z = 118 are not too optimistic. For this reason, and because of high instability of superheavy nuclei, we comment on some structure effects, connected with the K-isomerism phenomenon which could lead to a significant increase in the stability of these systems.

  6. Structural and decay properties of $Z=132,138$ superheavy nuclei

    CERN Document Server

    Rather, Asloob A; Usmani, A A; Kumar, Bharat; Patra, S K

    2016-01-01

    In this paper, we analyze the structural properties of $Z=132$ and $Z=138$ superheavy nuclei within the ambit of axially deformed relativistic mean-field framework with NL$3^{*}$ parametrization and calculate the total binding energies, radii, quadrupole deformation parameter, separation energies, density distributions. We also investigate the phenomenon of shape coexistence by performing the calculations for prolate, oblate and spherical configurations. For clear presentation of nucleon distributions, the two-dimensional contour representation of individual nucleon density and total matter density has been made. Further, a competition between possible decay modes such as $\\alpha$-decay, $\\beta$-decay and spontaneous fission of the isotopic chain of superheavy nuclei with $Z=132$ within the range 312 $\\le$ A $\\le$ 392 and 318 $\\le$ A $\\le$ 398 for $Z=138$ is systematically analyzed within self-consistent relativistic mean field model. From our analysis, we inferred that the $\\alpha$-decay and spontaneous fiss...

  7. Fusion-fission probabilities, cross sections and structure notes of super-heavy nuclei

    CERN Document Server

    Kowal, Michał; Jachimowicz, Piotr; Skalski, Janusz; Siwek-Wilczyńska, Krystyna; Wilczyński, Janusz

    2016-01-01

    Fusion - fission probabilities in the synthesis of heaviest elements are discussed in the context of the latest experimental reports. Cross sections for superheavy nuclei are evaluated using "Fusion by Diffusion" (FBD) model. Predictive power of this approach is shown for experimentally known Lv, Og isotopes and predictions given for Z=119,120. Ground state and saddle point properties as: masses, shell corrections, pairing energies and deformations necessary for cross section estimations are calculated systematically within the multidimensional microscopic - macroscopic method based on the deformed Woods-Saxon single particle potential. In the frame of FBD approach predictions for production of elements heavier than Z = 118 are not too optimistic. For this reason, and because of high instability of superheavy nuclei, we comment on some structure effects, connected with the K-isomerism phenomenon which could lead to a significant increase in the stability of these systems.

  8. Heavy particle radioactivity from superheavy nuclei leading to $^{298}$114 daughter nuclei

    CERN Document Server

    Santhosh, K P

    2013-01-01

    The feasibility for the alpha decay and the heavy particle decay from the even-even superheavy (SH) nuclei with Z = 116-124 have been studied within the Coulomb and proximity potential model (CPPM). The Universal formula for cluster decay (UNIV) of Poenaru et al., the Universal Decay Law (UDL) and the Scaling Law of Horoi et al., has also been used for the evaluation of the decay half lives. A comparison of our predicted half lives with the values evaluated using these empirical formulas are in agreement with each other and hence CPPM could be considered as a unified model for alpha and cluster decay studies. Within our fission model, we have studied cluster formation probability for various clusters and the maximum cluster formation probability for the decay accompanying $^{298}$114 reveals its doubly magic behavior. In the plots for log_10(T_1/2) against the neutron number of the daughter in the corresponding decay, the half life is found to be the minimum for the decay leading to $^{298}$114 (Z = 114, N = ...

  9. Heavy particle radioactivity from superheavy nuclei leading to {sup 298}114 daughter nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Santhosh, K.P., E-mail: drkpsanthosh@gmail.com; Priyanka, B.

    2014-09-15

    The feasibility for the alpha decay and the heavy particle decay from the even–even superheavy (SH) nuclei with Z=116–124 has been studied within the Coulomb and proximity potential model (CPPM). Our predicted half lives agree well with the values evaluated using the Universal formula for cluster decay (UNIV) of Poenaru et al., the Universal Decay Law (UDL) of Qi et al., and the Scaling Law of Horoi et al. The spontaneous fission half lives of the corresponding parents have also been evaluated using the semi-empirical formula of Santhosh et al. Within our fission model, we have studied the cluster formation probability for various clusters and the maximum cluster formation probability is found for the decay accompanying {sup 298}114. In the plots for log{sub 10}(T{sub 1/2}) against the neutron number of the daughter in the corresponding decay, the half life is found to be the minimum for the decay leading to {sup 298}114 (Z=114, N=184). Most of the predicted half lives are well within the present upper limit for measurements (T{sub 1/2}<10{sup 30} s) and the computed alpha half lives for {sup 290,292}Lv agree well with the experimental data.

  10. Heavy particle radioactivity from superheavy nuclei leading to 298114 daughter nuclei

    Science.gov (United States)

    Santhosh, K. P.; Priyanka, B.

    2014-09-01

    The feasibility for the alpha decay and the heavy particle decay from the even-even superheavy (SH) nuclei with Z = 116- 124 has been studied within the Coulomb and proximity potential model (CPPM). Our predicted half lives agree well with the values evaluated using the Universal formula for cluster decay (UNIV) of Poenaru et al., the Universal Decay Law (UDL) of Qi et al., and the Scaling Law of Horoi et al. The spontaneous fission half lives of the corresponding parents have also been evaluated using the semi-empirical formula of Santhosh et al. Within our fission model, we have studied the cluster formation probability for various clusters and the maximum cluster formation probability is found for the decay accompanying 298114. In the plots for log10 (T1/2) against the neutron number of the daughter in the corresponding decay, the half life is found to be the minimum for the decay leading to 298114 (Z = 114, N = 184). Most of the predicted half lives are well within the present upper limit for measurements (T1/2 <1030 s) and the computed alpha half lives for 290,292Lv agree well with the experimental data.

  11. New approach for alpha decay half-lives of superheavy nuclei and applicability of WKB approximation

    OpenAIRE

    Dong, Jianmin; Zuo, Wei; Scheid, Werner

    2011-01-01

    The alpha decay half-lives of recently synthesized superheavy nuclei (SHN) are calculated by applying a new approach which estimates them with the help of their neighbors based on some simple formulas. The estimated half-life values are in very good agreement with the experimental ones, indicating the reliability of the experimental observations and measurements to a large extent as well as the predictive power of our approach. The second part of this work is to test the applicability of the ...

  12. Alpha-decay energies of superheavy nuclei for the Fayans functional

    CERN Document Server

    Tolokonnikov, S V; Kortelainen, M; Lutostansky, Yu S; Saperstein, E E

    2016-01-01

    Alpha-decay energies for several chains of super-heavy nuclei are calculated by using Fayans functional FaNDF$^0$. They are compared to the experimental data and predictions of two Skyrme functionals, SLy4 and SkM*, and of the macro-micro method as well. The corresponding lifetimes are calculated with the use of the semi-phenomenological formulas by Parkhomenko and Sobiczewski and by Royer and Zhang.

  13. Search for possible superheavy particles in sodium nuclei

    Science.gov (United States)

    Dick, W. J.; Greenlees, G. W.; Kaufman, S. L.

    1986-01-01

    A search has been made for isotopes of sodium of mass >100 amu. Such heavy isotopes could arise from the presence of superheavy particles in the primordial soup which became constituents of nuclear matter. The experimental technique involved studying the isotopic mass shift of the Na D2 atomic transition using high-resolution laser spectroscopy and the photon-burst method. An upper limit for the heavy-particle-to-nucleon ratio of 5×10-12 was found. Cosmological-model predictions for this ratio in nuclear matter are ~=10-10. Any comparison of these two values assumes no mass fractionation has occurred in the geophysical disposition and subsequent extraction of the sodium forming the atomic beam and also no differences in the distribution of heavy isotopes among the elements, compared to normal isotopes, during their astrophysical formation. Making these assumptions enables limits to be placed on the heavy-particle annihilation cross sections in the formation process.

  14. Search for possible superheavy particles in sodium nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Dick, W.J.; Greenlees, G.W.; Kaufman, S.L.

    1986-01-01

    A search has been made for isotopes of sodium of mass >100 amu. Such heavy isotopes could arise from the presence of superheavy particles in the primordial soup which became constituents of nuclear matter. The experimental technique involved studying the isotopic mass shift of the Na D2 atomic transition using high-resolution laser spectroscopy and the photon-burst method. An upper limit for the heavy-particle-to-nucleon ratio of 5 x 10 S was found. Cosmological-model predictions for this ratio in nuclear matter are approx. =10 . Any comparison of these two values assumes no mass fractionation has occurred in the geophysical disposition and subsequent extraction of the sodium forming the atomic beam and also no differences in the distribution of heavy isotopes among the elements, compared to normal isotopes, during their astrophysical formation. Making these assumptions enables limits to be placed on the heavy-particle annihilation cross sections in the formation process.

  15. Recent α decay half-lives and analytic expression predictions including superheavy nuclei

    Science.gov (United States)

    Royer, G.; Zhang, H. F.

    2008-03-01

    New recent experimental α decay half-lives have been compared with the results obtained from previously proposed formulas depending only on the mass and charge numbers of the α emitter and the Qα value. For the heaviest nuclei they are also compared with calculations using the Density-Dependent M3Y (DDM3Y) effective interaction and the Viola-Seaborg-Sobiczewski (VSS) formulas. The correct agreement allows us to make predictions for the α decay half-lives of other still unknown superheavy nuclei from these analytic formulas using the extrapolated Qα of G. Audi, A. H. Wapstra, and C. Thibault [Nucl. Phys. A729, 337 (2003)].

  16. Long lifetime components in the decay of excited super-heavy nuclei

    Directory of Open Access Journals (Sweden)

    Morjean M.

    2013-12-01

    Full Text Available For nuclear reactions in which super-heavy nuclei can be formed, the essential difference between the fusion process followed by fission and non-equilibrium processes leading to fission-like fragments is there action time. Quite probable non-equilibrium processes, characterized by very short reaction times, are highlighted thanks to mass-angle correlations. However, long lifetime components associated with fission following fusion have been observed with two independent experimental techniques, providing evidence for the formation of compound nuclei with Z = 120 and 124, followed by mass asymmetric fission.

  17. Microscopic Analysis of the α-DECAY in Heavy and Superheavy Nuclei

    Science.gov (United States)

    Delion, D. S.; Sandulescu, A.; Greiner, W.

    2004-09-01

    We analyze the α-decay along N - Z chains in heavy and superheavy nuclei. The α-particle preformation amplitude is estimated within the pairing model, while the penetration part by the deformed WKB approach. We show that for N > 126 the plateau condition is not fulfilled along any α-chain, namely the logarithmic derivative of the Coulomb function changes much faster in comparison with that of the preformation factor. We correct this deficiency by considering an α-cluster factor in the preformation amplitude, depending upon the Coulomb parameter. For superheavy region an additional dependence upon the number of interacting α-particles indicates a clustering feature connected with a larger radial component.

  18. Exotic decay modes of odd-Z (105-119) superheavy nuclei

    Science.gov (United States)

    Rajeswari, N. S.; Balasubramaniam, M.

    2014-06-01

    Half-lives of proton emission for proton emitters with Z = 51 to 83 are calculated, in the frame-work of unified fission model with the penetrability calculated using the WKB approximation. For all the ground and isomeric state of the proton, the deformation degree of freedom is included. Calculated half-lives are in good agreement with the experimental ones. Experimentally for a few isotopes, proton and alpha branches are reported. Hence we have calculated the half-lives of alpha decay for these elements. For parent nuclei 157Ta, 166Ir, 167Ir, 176Tl and 177Tl, the alpha decay mode is preferred over the proton emission. Further, the calculations are extended to find half-lives of superheavy element with odd proton number in the range Z = 105 to 119, for both proton, alpha and for a few cluster decays. Calculations on superheavy elements reveal that cluster radioactivity has half-lives comparable with proton emissions. It is found that proton emission is the primary competing decay mode with respect to alpha decay for superheavy elements. Among considered clusters, 12C, 20Ne and 24Mg are found to have lowest half-lives among other N = Z clusters and for a few clusters the half-lives are found to be comparable with that of proton emission.

  19. Exotic decay modes of odd-Z (105-119) superheavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Rajeswari, N.S. [Bharathiar University, Department of Physics, Coimbatore (India); Avinashilingam Institute for Home Science and Higher Education for Women - University, Department of Physics, Coimbatore (India); Balasubramaniam, M. [Bharathiar University, Department of Physics, Coimbatore (India)

    2014-06-15

    Half-lives of proton emission for proton emitters with Z = 51 to 83 are calculated, in the frame-work of unified fission model with the penetrability calculated using the WKB approximation. For all the ground and isomeric state of the proton, the deformation degree of freedom is included. Calculated half-lives are in good agreement with the experimental ones. Experimentally for a few isotopes, proton and alpha branches are reported. Hence we have calculated the half-lives of alpha decay for these elements. For parent nuclei {sup 157}Ta, {sup 166}Ir, {sup 167}Ir, {sup 176}Tl and {sup 177}Tl, the alpha decay mode is preferred over the proton emission. Further, the calculations are extended to find half-lives of superheavy element with odd proton number in the range Z = 105 to 119, for both proton, alpha and for a few cluster decays. Calculations on superheavy elements reveal that cluster radioactivity has half-lives comparable with proton emissions. It is found that proton emission is the primary competing decay mode with respect to alpha decay for superheavy elements. Among considered clusters, {sup 12}C, {sup 20}Ne and {sup 24}Mg are found to have lowest half-lives among other N = Z clusters and for a few clusters the half-lives are found to be comparable with that of proton emission. (orig.)

  20. Effects of Isospin Equilibrium on Cold Fusion of Superheavy Nuclei

    Institute of Scientific and Technical Information of China (English)

    LIU Zu-Hua; BAO Jing-Dong

    2005-01-01

    @@ The neutron flow model predicts that neutrons start to flow freely between the approaching nuclei 58Fe and 208 Pb at s = 3fm, a length in which the effective surfaces of these nuclei are 3fm apart. As a result of neutron flow,the N/Z value rapidly reaches an equilibrium distribution. Meanwhile the system, originally in the fusion valley,is injected into the asymmetric fission valley. The dynamic process of the composite nucleus in the asymmetric fission valley is treated with a two-parameter Smoluchowski equation. It is shown that the probability to overcome the asymmetric fission barrier and to achieve compound nucleus configuration, hence the fusion cross section is obviously suppressed due to the effect of isospin equilibrium.

  1. A statistical approach to describe highly excited heavy and superheavy nuclei

    Science.gov (United States)

    Chen, Peng-Hui; Feng, Zhao-Qing; Li, Jun-Qing; Zhang, Hong-Fei

    2016-09-01

    A statistical approach based on the Weisskopf evaporation theory has been developed to describe the de-excitation process of highly excited heavy and superheavy nuclei, in particular for the proton-rich nuclei. The excited nucleus is cooled by evaporating γ-rays, light particles (neutrons, protons, α etc) in competition with binary fission, in which the structure effects (shell correction, fission barrier, particle separation energy) contribute to the processes. The formation of residual nuclei is evaluated via sequential emission of possible particles above the separation energies. The available data of fusion-evaporation excitation functions in the 28Si+198Pt reaction can be reproduced nicely within the approach. Supported by Major State Basic Research Development Program in China (2015CB856903), National Natural Science Foundation of China Projects (11175218, U1332207, 11475050, 11175074), and Youth Innovation Promotion Association of Chinese Academy of Sciences

  2. Toroidal Nuclear Matter Distributions of Superheavy Nuclei from Constrained Skyrme-HFB Calculations

    Energy Technology Data Exchange (ETDEWEB)

    Kosior, Amelia [Maria Curie-Sklodowska University, Poland; Staszczak, A. [Maria Curie-Sklodowska University, Poland; Wong, Cheuk-Yin [ORNL

    2017-01-01

    Using the Hartree Fock Bogoliubov (HFB) self-consistent mean-field theory with the SkM* Skyrme energy-density functional, we study nuclear structure properties of even even superheavy nuclei (SHN) of Z = 120 isotopes and N = 184 isotones. The shape of the nucleus along the lowest energy curve as a function of the quadrupole moment Q20 makes a sud- den transition from the oblate spheroids (biconcave discs) to the toroidal shapes, in the region of large oblate quadrupole moments.

  3. Alpha-decay energies of superheavy nuclei for the Fayans functional

    Energy Technology Data Exchange (ETDEWEB)

    Tolokonnikov, S.V. [National Research Centre ' ' Kurchatov Institute' ' , Moscow (Russian Federation); Moscow Institute of Physics and Technology, Dolgoprudny (Russian Federation); Borzov, I.N. [National Research Centre ' ' Kurchatov Institute' ' , Moscow (Russian Federation); Joint Institute for Nuclear Research, Dubna (Russian Federation); Kortelainen, M. [University of Jyvaskyla, Department of Physics, P.O. Box 35 (YFL), Jyvaskyla (Finland); University of Helsinki, Helsinki Institute of Physics, P.O. Box 64, Helsinki (Finland); Lutostansky, Yu.S. [National Research Centre ' ' Kurchatov Institute' ' , Moscow (Russian Federation); Saperstein, E.E. [National Research Centre ' ' Kurchatov Institute' ' , Moscow (Russian Federation); National Research Nuclear University MEPhI, Moscow (Russian Federation)

    2017-02-15

    Alpha-decay energies for several chains of superheavy nuclei are calculated within the self-consistent mean-field approach by using the Fayans functional FaNDF{sup 0}. They are compared to the experimental data and predictions of two Skyrme functionals, SLy4 and SkM{sup *}, and of the macro-micro method as well. The corresponding lifetimes are calculated with the use of the semi-phenomenological formulas by Parkhomenko and Sobiczewski and by Royer and Zhang. (orig.)

  4. Breakup Densities of Hot Nuclei.

    Science.gov (United States)

    Viola, Vic

    2006-04-01

    Breakup densities of hot ^197Au-like residues have been deduced from the systematic trends of Coulomb parameters required to fit intermediate-mass-fragment kinetic-energy spectra. The results indicate emission from nuclei near normal nuclear density below an excitation energy E*/A .3ex˜x 5 MeV. Temperatures derived from these data with a density-dependent Fermi-gas model yield a nuclear caloric curve that is generally consistent with those derived from isotope ratios.

  5. Traces of heavy and superheavy cosmic nuclei in olivines of extraterrestial origin

    Energy Technology Data Exchange (ETDEWEB)

    Ignatova, R.; Taneva, T. (Bylgarska Akademiya na Naukite, Sofia. Inst. za Yadrena Izsledvaniya i Yadrena Energetika); Pelas, P.; Stetsenko, S.; Perelgin, V. (Joint Inst. for Nuclear Research, Dubna (USSR))

    1982-01-01

    The paths of traces of WH nuclei from cosmic rays have been measured in olivines from the meteorites Maryalakhti, Eagle Stein, Liposki khutor with radiation ages 175, 45 and 220 million years respectively. 3 cm/sup 3/ olivines of these meteorites have been examined and more than 500 traces of nuclei with Z(>=)90 have been found measured including 3 traces 1.5-1.8 times longer than the traces created by the uranium and thorium nuclei. These traces may be left by nuclei with Z(>=)110. The crystals were chosen from localizations situated at 2-7 cm, 8-9 cm and 10-12 cm from the outside atmospheric surface of the meteorite. The abundancy of the Z(>=)50 nuclei in gigantic cosmic rays, averaged for a period of (<=) 200 millions of years has been compared with the distribution of the elements in the substances from the Solar system. A new value has been found for the hypothetical superheavy elements Z(>=)110 in galactic cosmic rays. It is 1.4 x 10 /sup -9/ from that of the iron group nuclei.

  6. Recent $\\alpha$ decay half-lives and analytic expression predictions including superheavy nuclei

    CERN Document Server

    Royer, G

    2008-01-01

    New recent experimental $\\alpha$ decay half-lives have been compared with the results obtained from previously proposed formulas depending only on the mass and charge numbers of the $\\alpha$ emitter and the Q$\\alpha$ value. For the heaviest nuclei they are also compared with calculations using the Density-Dependent M3Y (DDM3Y) effective interaction and the Viola-Seaborg-Sobiczewski (VSS) formulas. The correct agreement allows us to make predictions for the $\\alpha$ decay half-lives of other still unknown superheavy nuclei from these analytic formulas using the extrapolated Q$\\alpha$ of G. Audi, A. H. Wapstra, and C. Thibault [Nucl. Phys. A729, 337 (2003)].

  7. The formation and decay of superheavy nuclei produced in sup 4 sup 8 Ca-induced reactions

    CERN Document Server

    Kumar, S; Gupta, R K; Münzenberg, G; Scheid, W

    2003-01-01

    The formation of superheavy nuclei in sup 4 sup 8 Ca+ sup 2 sup 3 sup 2 Th, sup 2 sup 3 sup 8 U, sup 2 sup 4 sup 2 sup , sup 2 sup 4 sup 4 Pu and sup 2 sup 4 sup 8 Cm reactions and their subsequent decay are studied within the quantum mechanical fragmentation theory (QMFT) and the QMFT-based preformed cluster decay model (PCM) of Gupta and collaborators. According to QMFT, all these sup 4 sup 8 Ca-induced reactions are cold fusion reactions with relative excitation energies larger than those for the Pb-induced cold fusion reactions and smaller than those for the lighter beam, i.e. Mg, Si or S-induced hot fusion reactions. The same reactions were first suggested by Gupta et al in 1977 on the basis of QMFT, and this study re-establishes the same result. In fact, for such heavy isotopes of Z = 110 to 116, sup 5 sup 0 Ca is shown to be a better beam for cold fusion, but sup 5 sup 0 Ca is a radioactive nucleus. The alpha-decay half-lives of these nuclei after 3n and/or 4n evaporations, i.e. of the evaporation resi...

  8. K -shell ionization during α decay of polonium isotopes and superheavy nuclei

    Science.gov (United States)

    Trzhaskovskaya, M. B.; Nikulin, V. K.

    2016-03-01

    The theory of K -shell ionization during α decay of the 84Po isotopes is considered in detail as a part of our general study of the inner shell ionization probability of heavy and superheavy nuclei. Calculations of K -shell ionization with allowance made for the α -particle tunneling through the atomic Coulomb barrier have been performed in the framework of the fully quantum mechanical treatment developed for the first time by Anholt and Amundsen. Further information is available [Anholt and Amundsen, Phys. Rev. A 25, 169 (1982), 10.1103/PhysRevA.25.169]. As distinct from all previous the K -shell ionization calculations where the Dirac hydrogenlike wave functions have been used, we have found the discrete and continuum electron wave functions in the framework of the relativistic self-consistent Dirac-Fock method. In addition, we have taken into consideration accurately terms associated with the α -particle tunneling. Our exact calculations show that the tunneling contribution to the ionization probability is of great importance while Anholt and Amundsen have asserted that the contribution is small. We have obtained that the K -shell ionization probability during α decay of five isotopes of 84Po correlate better with the available experimental data providing the tunneling is included in calculations. New calculations for K -shell ionization during α decay of superheavy elements Fm249100,No253102,Rg272111, as well as Rn22286 are also presented. The data may be of importance in the combined α ,γ , and conversion-electron spectroscopy used in the superheavy element synthesis analysis.

  9. Correlations between neutrons and protons near Fermi surface and $Q_{\\alpha}$ of super-heavy nuclei

    CERN Document Server

    Wang, Ning; Wu, Xizhen; Meng, Jie

    2015-01-01

    The shell corrections and shell gaps in nuclei are systematically studied with the latest Weizs\\"acker-Skyrme (WS4) mass model. We find that most of asymmetric nuclei with (sub)-shell closures locate along the shell stability line (SSL), $N=1.37Z+13.5$, which might be due to a strong correlation between neutrons and protons near Fermi surface. The double magicity of nuclei $^{46}$Si and $^{78}$Ni is predicted according to the corresponding shell gaps, shell corrections and nuclear deformations. The unmeasured super-heavy nuclei $^{296}$118 and $^{298}$120, with relatively large shell gaps and shell corrections, also locate along the SSL, whereas the traditional magic nucleus $^{298}$Fl evidently deviates from the line. The $\\alpha$-decay energies of super-heavy nuclei with $Z=113-126$ are simultaneously investigated by using the WS4 model together with the radial basis function corrections. For super-heavy nuclei with large shell corrections, the smallest $\\alpha$-decay energy for elements $Z=116$, 117 and 11...

  10. New approach for alpha decay half-lives of superheavy nuclei and applicability of WKB approximation

    Science.gov (United States)

    Dong, Jianmin; Zuo, Wei; Scheid, Werner

    2011-07-01

    The α decay half-lives of recently synthesized superheavy nuclei (SHN) are calculated by applying a new approach which estimates them with the help of their neighbors based on some simple formulas. The estimated half-life values are in very good agreement with the experimental ones, indicating the reliability of the experimental observations and measurements to a large extent as well as the predictive power of our approach. The second part of this work is to test the applicability of the Wentzel-Kramers-Brillouin (WKB) approximation for the quantum mechanical tunneling probability. We calculated the accurate barrier penetrability for alpha decay along with proton and cluster radioactivity by numerically solving Schrödinger equation. The calculated results are compared with those of the WKB method to find that WKB approximation works well for the three physically analogical decay modes.

  11. New approach for alpha decay half-lives of superheavy nuclei and applicability of WKB approximation

    Energy Technology Data Exchange (ETDEWEB)

    Dong Jianmin [Research Center for Hadron and CSR Physics, Lanzhou University and Institute of Modern Physics of CAS, Lanzhou 730000 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Institute for Theoretical Physics, Justus Liebig University, D-35392 Giessen (Germany); China Institute of Atomic Energy, P.O. Box 275(18), Beijing 102413 (China); Zuo Wei, E-mail: zuowei@impcas.ac.cn [Research Center for Hadron and CSR Physics, Lanzhou University and Institute of Modern Physics of CAS, Lanzhou 730000 (China); School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Scheid, Werner [Institute for Theoretical Physics, Justus Liebig University, D-35392 Giessen (Germany)

    2011-07-01

    The {alpha} decay half-lives of recently synthesized superheavy nuclei (SHN) are calculated by applying a new approach which estimates them with the help of their neighbors based on some simple formulas. The estimated half-life values are in very good agreement with the experimental ones, indicating the reliability of the experimental observations and measurements to a large extent as well as the predictive power of our approach. The second part of this work is to test the applicability of the Wentzel-Kramers-Brillouin (WKB) approximation for the quantum mechanical tunneling probability. We calculated the accurate barrier penetrability for alpha decay along with proton and cluster radioactivity by numerically solving Schroedinger equation. The calculated results are compared with those of the WKB method to find that WKB approximation works well for the three physically analogical decay modes.

  12. New approach for alpha decay half-lives of superheavy nuclei and applicability of WKB approximation

    CERN Document Server

    Dong, Jianmin; Scheid, Werner; 10.1016/j.nuclphysa.2011.06.016

    2011-01-01

    The alpha decay half-lives of recently synthesized superheavy nuclei (SHN) are calculated by applying a new approach which estimates them with the help of their neighbors based on some simple formulas. The estimated half-life values are in very good agreement with the experimental ones, indicating the reliability of the experimental observations and measurements to a large extent as well as the predictive power of our approach. The second part of this work is to test the applicability of the Wentzel-Kramers-Brillouin (WKB) approximation for the quantum mechanical tunneling probability. We calculated the accurate barrier penetrability for alpha decay along with proton and cluster radioactivity by numerically solving Schr\\"odinger equation. The calculated results are compared with those of the WKB method to find that WKB approximation works well for the three physically analogical decay modes.

  13. Alpha Decay Potential Barriers and Half-Lives and Analytical Formula Predictions for Superheavy Nuclei

    Science.gov (United States)

    Royer, Guy; Zhang, Hongfei

    The α decay potential barriers are determined in the cluster-like shape path within a generalized liquid drop model including the proximity effects between the α particle and the daughter nucleus and adjusted to reproduce the experimental Qα. The α emission half-lives are determined within the WKB penetration probability. Calculations using previously proposed formulae depending only on the mass and charge of the alpha emitter and Qα are also compared with new experimental alpha-decay half-lives. The agreement allows to provide predictions for the α decay half-lives of other still unknown superheavy nuclei using the Qα determined from the 2003 atomic mass evaluation of Audi, Wapstra and Thibault.

  14. Fission half-lives of super-heavy nuclei in a microscopic approach

    CERN Document Server

    Warda, M

    2012-01-01

    A systematic study of 160 heavy and super-heavy nuclei is performed in the Hartree-Fock-Bogoliubov approach with the finite range and density dependent Gogny force with the D1S parameter set. We show calculations in several approximations: with axially symmetric and reflexion symmetric wave functions, with axially symmetric and non-reflexion symmetric wave functions and finally some representative examples with triaxial wave functions are also discussed. Relevant properties of the ground state and along the fission path are thoroughly analyzed. Fission barriers, Q$_\\alpha$-factors and lifetimes with respect to fission and $\\alpha$-decay as well as other observables are discussed. Larger configuration spaces and more general HFB wave functions as compared to previous studies provide a very good agreement with the experimental data.

  15. Review of even element super-heavy nuclei and search for element 120

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, S. [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Goethe-Universitaet Frankfurt, Institut fuer Physik, Frankfurt (Germany); Heinz, S.; Mann, R.; Maurer, J.; Barth, W.; Burkhard, H.G.; Dahl, L.; Kindler, B.; Kojouharov, I.; Lang, R.; Lommel, B.; Runke, J.; Scheidenberger, C.; Schoett, H.J.; Tinschert, K. [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Muenzenberg, G. [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Manipal University, Manipal Centre for Natural Sciences, Manipal, Karnataka (India); Antalic, S.; Saro, S. [Comenius University, Department of Nuclear Physics and Biophysics, Bratislava (Slovakia); Eberhardt, K.; Thoerle-Pospiech, P.; Trautmann, N. [Johannes Gutenberg-Universitaet Mainz, Mainz (Germany); Grzywacz, R. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); University of Tennessee, Knoxville, TN (United States); Hamilton, J.H. [Vanderbuilt University, Department of Physics and Astronomy, Nashville, TN (United States); Henderson, R.A.; Kenneally, J.M.; Moody, K.J.; Shaughnessy, D.A.; Stoyer, M.A. [Lawrence Livermore National Laboratory, Livermore, CA (United States); Miernik, K. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); University of Warsaw, Warsaw (Poland); Miller, D. [University of Tennessee, Knoxville, TN (United States); Morita, K. [RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama (Japan); Nishio, K. [Japan Atomic Energy Agency, Tokai, Ibaraki (Japan); Popeko, A.G.; Yeremin, A.V. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Roberto, J.B.; Rykaczewski, K.P. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Uusitalo, J. [University of Jyvaeskylae, Department of Physics, Jyvaeskylae (Finland)

    2016-06-15

    The reaction {sup 54}Cr + {sup 248}Cm was investigated at the velocity filter SHIP at GSI, Darmstadt, with the intention to study production and decay properties of isotopes of element 120. Three correlated signals were measured, which occurred within a period of 279ms. The heights of the signals correspond with the expectations for a decay sequence starting with an isotope of element 120. However, a complete decay chain cannot be established, since a signal from the implantation of the evaporation residue cannot be identified unambiguously. Measured properties of the event chain are discussed in detail. The result is compared with theoretical predictions. Previously measured decay properties of even element super-heavy nuclei were compiled in order to find arguments for an assignment from the systematics of experimental data. In the course of this review, a few tentatively assigned data could be corrected. New interpretations are given for results which could not be assigned definitely in previous studies. The discussion revealed that the cross-section for production of element 120 could be high enough so that a successful experiment seems possible with presently available techniques. However, a continuation of the experiment at SHIP for a necessary confirmation of the results obtained in a relatively short irradiation of five weeks is not possible at GSI presently. Therefore, we decided to publish the results of the measurement and of the review as they exist now. In the summary and outlook section we also present concepts for the continuation of research in the field of super-heavy nuclei. (orig.)

  16. ON THE MICROSCOPIC AND MACROSCOPIC ASPECTS OF NUCLEAR STRUCTURE WITH APPLICATIONS TO SUPERHEAVY NUCLEI

    Energy Technology Data Exchange (ETDEWEB)

    Tsang, Chin-Fu.

    1969-05-22

    The thesis is concerned with the relation between a microscopic approach and a macroscopic approach to the study of the nuclear binding energy as a function of neutron number, proton number and nuclear deformations. First of all we give a general discussion of the potential energy of a system which can be divided into a bulk region and a thin skin layer. We find that this energy can be written down in the usual liquid drop type of expression, i.e., in terms of the volume, the surface area and other macroscopic properties of the system. The discussion is illustrated by a study of noninteracting particles in an orthorhombic potential well with zero potential inside and infinite potential outside. The total energy is calculated both exactly (a microscopic approach) and also from a liquid drop type of expression (a macroscopic approach). It turns out that the latter approach reproduces the smooth average of the exact results very well. We next make a digression to study the saddle point shapes of a charged conducting drop on a pure liquid drop model. We compare the properties of a conducting drop with those of a drop whose charges are distributed uniformly throughout its volume. The latter is the usual model employed in the study of nuclear fission. We also determined some of the more important symmetric saddle point shapes. In the last part of the thesis we generalize a method due to Strutinski to synthesize a microscopic approach (the Nilsson model) and a macroscopic approach (the liquid drop model). The results are applied to realistic nuclei. The possible occurrence of shape isomers comes as a natural consequence of the present calculation. Their trends as a function of neutron and proton members are discussed and the results are tabulated. We also work out the stabilities of the predicted superheavy nuclei with proton number around 114 and neutron number around 184 and 196. Some of these nuclei appear to have extremely long life times. The possible experimental

  17. Alpha-decay of deformed superheavy nuclei as a probe of shell closures

    Science.gov (United States)

    Ismail, M.; Seif, W. M.; Adel, A.; Abdurrahman, A.

    2017-02-01

    A systematic study on α-decay half-life time, Tα, of α-particle emission from a large number of deformed heavy and superheavy nuclei is presented. The calculations are employed in the framework of the density-dependent cluster model. The microscopic α-daughter nuclear interaction potential is calculated in the framework of the double-folding model with the realistic effective Michigan-three-Yukawa Reid nucleon-nucleon interaction. We study the neutron number variation of log Tα and arranged different isotones at each neutron magic number according to their stability, in the sense that the more stable isotone corresponds to the lowest value of log Tα. We found that the half-life time becomes minimum when the neutron or proton numbers of the corresponding daughter nucleus are magic. Moreover, the half-life time is maximum for parent nucleus with magicity. The nuclear stability is assumed to be proportional with the depth of the minimum value in log Tα for the daughter nucleus or the height of its maximum value for the parent one. The neutron magic numbers predicted and confirmed from the present study are 126, 152, 162, 172, 184, 196, 202 and 212, most of them were deduced by other authors based on different methods.

  18. Fission dynamics of hot nuclei

    Indian Academy of Sciences (India)

    Santanu Pal; Jhilam Sadhukhan

    2014-04-01

    Experimental evidence accumulated during the last two decades indicates that the fission of excited heavy nuclei involves a dissipative dynamical process. We shall briefly review the relevant dynamical model, namely the Langevin equations for fission. Statistical model predictions using the Kramers’ fission width will also be discussed.

  19. Systematic Study on Alpha Decay Half-Lives of Superheavy Nuclei

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The α-decay half-lives of a set of superheavy nuclear isotope chain from Z = 105 to 120 have been analyzed systematically within the WKB method, and some nuclear structure features are found. The decay barriers have been determined in the quasi-molecular shape path within the Generalized Liquid Drop Model (GLDM) including the proximity effects between nucleons in a neck and the mass and charge asymmetry. The results are in reasonable agreement with the published experimental data for the alpha decay half-lives of isotopes of charge 112, 114, and 116, of the element 294118 and of some decay products. A comparison of present calculations with the results by the DDM3Y effective interaction and by the Viola-Seaborg-Sobiczewski (VSS) formulae is also made. The experimental α decay half lives all stand in between the GLDM calculations and VSS formula results. This demonstrates the possibility of these models to provide reasonable estimates for the half-lives of nuclear decays by α emissions for the domain of SHN. The half-lives of these new nuclei are thus well tested from the reasonable consistence of the macroscopic, the microscopic, the empirical formulae and the experimental data. This also shows that the present data of SHN themselves are consistent.It could suggest that the present experimental claims on the existence of new elements Z = 110 ~ 118 are reliable.It is expected that greater deviations of a few SHN between the data and the model may be eliminated by further improvements on the precision of the measurements.

  20. Mean-field studies of time reversal breaking states in super-heavy nuclei with the Gogny force

    Energy Technology Data Exchange (ETDEWEB)

    Robledo, L. M., E-mail: luis.robledo@uam.es [Departamento Física Teórica, Facultad de Ciencias, Universidad Autónoma de Madrid, E-28049 Madrid (Spain)

    2015-10-15

    Recent progress on the description of time reversal breaking (odd mass and multi-quasiparticle excitation) states in super-heavy nuclei within a mean field framework and using several flavors of the Gogny interaction is reported. The study includes ground and excited states in selected odd mass isotopes of nobelium and mendelevium as well as high K isomeric states in {sup 254}No. These are two and four-quasiparticle excitations that are treated in the same self-consistent HFB plus blocking framework as the odd mass states.

  1. Rotational properties in even-even superheavy $^{254-258}$Rf nuclei based on total-Routhian-surface calculations

    CERN Document Server

    Hua-Lei, Wang; Jin-Ge, Jiang; Min-Liang, Liu

    2013-01-01

    High-spin yrast structures of even-even superheavy nuclei $^{254-258}$Rf are investigated by means of total-Routhian-surface approach in three-dimensional ($\\beta_2, \\gamma, \\beta_4$) space. The behavior in the moments of inertia of $^{256}$Rf is well reproduced by our calculations, which is attributed to the $j_{15/2}$ neutron rotation-alignment. The competition between rotationally aligned $i_{13/2}$ proton and $j_{15/2}$ neutron is discussed. High-spin predictions are also made for its neighboring isotopes $^{254,258}$Rf.

  2. Comment on Breakup Densities of Hot Nuclei

    CERN Document Server

    Viola, V E; Natowitz, J B; Yennello, S J

    2006-01-01

    In [1,2]the observed decrease in spectral peak energies of IMFs emitted from hot nuclei was interpreted in terms of a breakup density that decreased with increasing energy. Subsequently, Raduta et al. [3] performed MMM simulations that showed decreasing spectral peaks could be obtained at constant density. In this letter we examine this apparent inconsistency.

  3. GDR in Hot Nuclei: New Measurements

    Science.gov (United States)

    Camera, F.; Kmiecik, M.; Wieland, O.; Benzoni, G.; Bracco, A.; Brambilla, S.; Crespi, F.; Mason, P.; Moroni, A.; Million, B.; Leoni, S.; Maj, A.; Styczen, J.; Brekiesz, M.; Meczynski, W.; Zieblinski, M.; Gramegna, F.; Barlini, S.; Kravchuk, V. L.; Lanchais, A. L.; Mastinu, P. F.; Bruno, M.; D'Agostino, M.; Geraci, E.; Ordine, A.; Casini, G.; Chiari, M.

    2005-04-01

    The measured properties of the Giant Dipole Resonance in hot rotating nuclei are successfully described with the model of thermal fluctuations, even though there are still some open problems especially at very low (T 2.5MeV) temperatures and missing data in some mass regions. Recent experimental works have addressed more specific problems regarding the nuclear shape and its behaviour in very particular and delimited phase space regions. In this paper will be discussed new exclusive measurements of the GDR γ decay in heavy 216Rn nuclei (where the shape of nuclei surviving fission have been probed) and some preliminary data on the 132Ce nuclei at very high excitation energy.

  4. Cold reaction valleys in the radioactive decay of superheavy {286}^112, {292}^114 and {296}^116 nuclei

    CERN Document Server

    Santhosh, K P

    2012-01-01

    Cold reaction valleys in the radioactive decay of superheavy nuclei {286}^112, {292}^114 and {296}^116 are studied taking Coulomb and Proximity Potential as the interacting barrier. It is found that in addition to alpha particle, 8^Be, 14^C, 28^Mg, 34^Si, 50^Ca, etc. are optimal cases of cluster radioactivity since they lie in the cold valleys. Two other regions of deep minima centered on 208^Pb and 132^Sn are also found. Within our Coulomb and Proximity Potential Model half-life times and other characteristics such as barrier penetrability, decay constant for clusters ranging from alpha particle to 68^Ni are calculated. The computed alpha half-lives match with the values calculated using Viola--Seaborg--Sobiczewski systematics. The clusters 8^Be and 14^C are found to be most probable for emission with T_1/2 < 1030s. The alpha-decay chains of the three superheavy nuclei are also studied. The computed alpha decay half-lives are compared with the values predicted by Generalized Liquid Drop Model and they are...

  5. NUCLEAR AND HEAVY ION PHYSICS: α-decay half-lives of superheavy nuclei and general predictions

    Science.gov (United States)

    Dong, Jian-Min; Zhang, Hong-Fei; Wang, Yan-Zhao; Zuo, Wei; Su, Xin-Ning; Li, Jun-Qing

    2009-08-01

    The generalized liquid drop model (GLDM) and the cluster model have been employed to calculate the α-decay half-lives of superheavy nuclei (SHN) using the experimental α-decay Q values. The results of the cluster model are slightly poorer than those from the GLDM if experimental Q values are used. The prediction powers of these two models with theoretical Q values from Audi et al. (QAudi) and Muntian et al. (QM) have been tested to find that the cluster model with QAudi and QM could provide reliable results for Z > 112 but the GLDM with QAudi for Z <= 112. The half-lives of some still unknown nuclei are predicted by these two models and these results may be useful for future experimental assignment and identification.

  6. Theoretical predictions on the decay properties of superheavy nuclei Z = 123 in the region 297 ≤ A ≤ 307

    Science.gov (United States)

    Santhosh, K. P.; Nithya, C.

    2016-12-01

    Decay modes of isotopes of the superheavy element Z = 123 within the range 297 ≤ A ≤ 307 have been studied by comparing the alpha decay half-lives with the spontaneous fission half-lives. Three different mass tables were used for the calculation of the alpha decay energy. A close study of alpha decay half-lives within the range 297 ≤ A ≤ 307 has been performed using the Coulomb and proximity potential model for deformed nuclei (CPPMDN). The alpha half-lives calculated using CPPMDN are in harmony with the values obtained by the Viola-Seaborg systematic, the universal curve of Poenaru et al., and the analytical formula of Royer. Spontaneous fission half-lives are evaluated using the new shell-effect-dependent formula proposed by Santhosh et al., and the semi-empirical formula of Xu et al. Through our study it is seen that the isotopes 300-303123 exhibit 8α chains and the isotopes 304-307123 exhibit 5α chains with half-lives in a measurable range. Clearly the isotopes of Z = 123 within the range 300 ≤ A ≤ 307 will decay through alpha emission followed by spontaneous fission and thus can be predicted as synthesized and detected in laboratory via alpha decay. Since the predictions on decay modes of isotopes of the superheavy element Z = 123 is done for the first time it is hoped that the study will open up new areas in experimental investigations.

  7. Predictions on the alpha decay chains of superheavy nuclei with Z =121 within the range 290 $\\leq$ A $\\leq$ 339

    CERN Document Server

    Santhosh, K P

    2016-01-01

    A systematic study on the alpha decay half lives of various isotopes of superheavy element \\textit{Z} = 121 within the range 290 $\\leq$ A $\\leq$ 339 is presented for the first time using Coulomb and proximity potential model for deformed nuclei (CPPMDN). The calculated $\\alpha$ decay half lives of the isotopes within our formalism match well with the values computed using Viola-Seaborg systematic, Universal curve of Poenaru et al., and the analytical formula of Royer. In our study by comparing the $\\alpha$ decay half lives with the spontaneous fission half lives, we have predicted $2\\alpha$ chain from $^{309, 311, 312}$121, $3\\alpha$ chain from $^{310}$121 and $1\\alpha$ chain from $^{313, 314}$121. Clearly our study shows that the isotopes of superheavy element \\textit{Z} = 121 within the mass range 309 $\\leq$ A $\\leq$ 314 will survive fission and can be synthesized and detected in the laboratory via alpha decay. We hope that our predictions will provide a new guide to future experiments.

  8. Disappearance of collective motion in hot nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Santonocito, D.; Piattelli, P.; Agodi, C.; Alba, R.; Bellia, G.; Coniglione, R.; Del Zoppo, A.; Finocchiaro, P.; Hongmei, F.; Maiolino, C.; Migneco, E.; Sapienza, P. [INFN-LNS, Laboratori Nazionali del Sud, Catania (Italy); Blumenfeld, Y.; Delaunay, F.; Frascaria, N.; Lima, V.; Scarpaci, J. [Institut de Physique Nucleaire, IN2P3-CNRS, 91 - Orsay (France); Migneco, E. [Catania Univ., Dipartimento di Fisica (Italy)

    2003-07-01

    The evolution of the GDR {gamma} yield for excitation energies between 160 and 300 MeV has been investigated in nuclei of mass A {approx} 126 through the reactions {sup 116}Sn + {sup 12}C and {sup 24}Mg at 17 and 23 A*MeV. Gamma-rays were detected with MEDEA array in coincidence with residues detected in MACISTE. The evolution of the GDR parameters has been investigated as a function of the linear momentum transferred to the fused system. This procedure allowed us to select hot nuclei produced in incomplete fusion reactions with different excitation energies. The analysis of the {gamma} spectra and their comparison with CASCADE calculations is presented. Results suggest a saturation of the GDR yield between 200 and 300 MeV excitation energy. (authors)

  9. Double giant dipole resonance in hot nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Cinausero, M.; Rizzi, V.; Viesti, G.; Fabris, D.; Lunardon, M.; Moretto, S.; Nebbia, G.; Pesente, S.; Barbui, M.; Fioretto, E.; Prete, G.; Bracco, A.; Camera, F.; Million, B.; Leoni, S.; Wieland, O.; Benzoni, G.; Brambilla, S.; Airoldi, A.; Maj, A.; Kmiecik, M

    2004-02-09

    Signals from Double Dipole Giant Resonances (DGDR) in hot nuclei have been searched in a {gamma}-{gamma} coincidence experiment using the HECTOR array at the Laboratori Nazionali di Legnaro. The experimental single {gamma}-ray spectrum and the projection of the {gamma}-{gamma} matrix have been compared with a standard Monte Carlo Statistical Model code including only the single GDR excitation. These calculations have been used as background to determine the extra-yield associated with the DGDR de-excitation. Results have been compared with a previous experiment confirming the presence of the DGDR excitation in fusion-evaporation reactions.

  10. One-phonon excitations in hot nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Vdovin, A.I.; Kosov, D.S. [Joint Institute for Nuclear Research, Moscow (Russian Federation)

    1995-05-01

    Equations of the random-phase approximation for hot nuclei are derived in the formalism of thermo-field dynamics. The model Hamiltonian used in the derivation involves separable effective interactions in the particle-particle and particl-hole channels. This initial Hamiltonian that forms the basis of the quasiparticle-phonon model at T = O is expressed in terms of thermal quasiparticles by means of two successive canonical transformations, i.e., by the conventional and thermal Bogolyubov transformations. The coefficients in the transformations are determined by minimizing the free-energy potential of a hot nucleus in the thermal vacuum state. The part that describes excitations of the hot nucleus in the random-phase approximation is then singled out in the resulting Hamiltonian at T {ne} O. The variational principle is used to derive equations for one-phonon excitations. If the Hamiltonian involves only residual particle-hole interaction, these equations coincide with those obtained earlier by means of Green`s functions and linearization of the equations of motion. The approach developed here can be used to extend the treatment beyond the random-phase approximation. 15 refs.

  11. Viscosity: From air to hot nuclei

    Indian Academy of Sciences (India)

    Nguyen Dinh Dang

    2014-11-01

    After a brief review of the history of viscosity from classical to quantal fluids, a discussion of how the shear viscosity of a finite hot nucleus is calculated directly from the width and energy of the giant dipole resonance (GDR) of the nucleus is given in this paper. The ratio / with s being the entropy volume density, is extracted from the experimental systematic of GDR in copper, tin and lead isotopes at finite temperature . These empirical results are compared with the results predicted by several independent models, as well as with almost model-independent estimations. Based on these results, it is concluded that the ratio / in medium and heavy nuclei decreases with increasing to reach (1.3−4)$×\\hbar/(4 k_B)$ at = 5 MeV, which is almost the same as that obtained for quark-gluon plasma at > 170 MeV.

  12. Ternary fission of superheavy elements

    Science.gov (United States)

    Balasubramaniam, M.; Vijayaraghavan, K. R.; Manimaran, K.

    2016-01-01

    Ternary fission of superheavy nuclei is studied within the three-cluster model potential energy surfaces (PESs). Due to shell effects, the stability of superheavy nuclei has been predicted to be associated with Z =114 , 120, and 126 for protons and N =184 for neutrons. Taking some representative nuclei we have extended the ternary fission studies to superheavy nuclei. We adopted two minimization procedures to minimize the potential and considered different arrangements of the fragments. The PES from one-dimensional minimization reveals a strong cluster region favoring various ternary breakups for an arrangement in which the lightest fragment is kept at the center. The PES obtained from two-dimensional minimization reveals strong preference of ternary fragmentation in the true ternary fission region. Though the dominant decay mode of superheavy nuclei is α decay, the α -accompanied ternary breakup is found to be a nonfavorable one. Further, the prominent ternary combinations are found to be associated with the neutron magic number.

  13. Nucleon pairing correlations and the α cluster preformation probability inside heavy and superheavy nuclei

    Science.gov (United States)

    Seif, W. M.

    2015-01-01

    The presence of paired or unpaired protons and neutrons in the open-shell radioactive α emitter affects the preformation probability of the α cluster inside it. The α-preformation probability inside the odd ( Z )-even ( N ) , even ( Z )-odd ( N ) , and odd ( Z )-odd ( N ) α emitters is investigated. The study is restricted to those decays with no angular momentum transfer to make a precise prediction about the mere pairing effect. The extended cluster model of α decay and the WKB approximation are used by taking into account the deformation degrees of freedom to carry out the calculations for 105 parent nuclei in the mass region of A =175 -289 . The α + daughter interaction potential is calculated by using the Hamiltonian energy-density approach in terms of the SLy4 Skyrme-like interaction, then it is implemented to find the average decay width over the different orientations. The half-life of the decay is then estimated and employed in turn to extract the α-preformation probability by taking account of errors on both the released energy and the experimental half-life time. According to the present calculations, it is found that the α cluster preformation probability inside the nuclei which have unpaired nucleons is less than it would be in the neighboring nuclei of the same shell and subshell closures but have no unpaired nucleons. In particular, the effect of the single unpaired neutron in the even ( Z )-odd ( N ) nuclei is slightly larger than that of the single unpaired proton in the odd ( Z )-even ( N ) ones. The effect of the unpaired nucleons appears more clearly in the odd ( Z )-odd ( N ) nuclei which have both an unpaired neutron and an unpaired proton. Based on the obtained results, an empirical pairing term is added to the empirical formula [J. Phys. G 40, 105102 (2013), 10.1088/0954-3899/40/10/105102] that relates the α cluster preformation probability to the proton and neutron numbers outside the closed shells of the parent nucleus.

  14. Processes in massive nuclei reactions and the way to complete fusion of reactants. What perspectives for the synthesis of heavier superheavy elements?

    Science.gov (United States)

    Mandaglio, G.; Nasirov, A. K.; Curciarello, F.; De Leo, V.; Romaniuk, M.; Fazio, G.; Giardina, G.

    2012-12-01

    By using the dinuclear system (DNS) model we determine the capture of reactants at the first stage of reaction, the competition between the DNS decay by the quasifission (QF) and the complete fusion (CF) process up to formation of the compound nucleus (CN) having compact shape. Further evolution of the CN is considered as its fission into two fragments or formation of evaporation residues (ER) by its cooling after emission of neutrons or/and charged light particles. Disappearance of the CN fission barrier due to its fast rotation leads to the fast fission (FF) by formation of fissionlike fragments. The results of calculations for the mass symmetric 136Xe+136Xe reaction, almost mass symmetric 108Mo+144Ba reaction, and mass asymmetric like 24Mg+238U and 34S+248Cm reactions are discussed. The fusion probability PCN calculated for many massive nuclei reactions leading to formation of superheavy nuclei have been analyzed. The reactions which can lead in perspective to the synthesis of superheavy elements in the Z = 120 - 126 range and, eventually, also to heaviest nuclei, are discussed.

  15. Processes in massive nuclei reactions and the way to complete fusion of reactants. What perspectives for the synthesis of heavier superheavy elements?

    Directory of Open Access Journals (Sweden)

    Romaniuk M.

    2012-12-01

    Full Text Available By using the dinuclear system (DNS model we determine the capture of reactants at the first stage of reaction, the competition between the DNS decay by the quasifission (QF and the complete fusion (CF process up to formation of the compound nucleus (CN having compact shape. Further evolution of the CN is considered as its fission into two fragments or formation of evaporation residues (ER by its cooling after emission of neutrons or/and charged light particles. Disappearance of the CN fission barrier due to its fast rotation leads to the fast fission (FF by formation of fissionlike fragments. The results of calculations for the mass symmetric 136Xe+136Xe reaction, almost mass symmetric 108Mo+144Ba reaction, and mass asymmetric like 24Mg+238U and 34S+248Cm reactions are discussed. The fusion probability PCN calculated for many massive nuclei reactions leading to formation of superheavy nuclei have been analyzed. The reactions which can lead in perspective to the synthesis of superheavy elements in the Z = 120 − 126 range and, eventually, also to heaviest nuclei, are discussed.

  16. Ways to produce new superheavy isotopes with Z = 111-117 in charged particle evaporation channels

    Science.gov (United States)

    Hong, Juhee; Adamian, G. G.; Antonenko, N. V.

    2017-01-01

    The excitation functions of the production of new heaviest isotopes of superheavy nuclei with charge numbers 111-117 in the pxn and αxn evaporation channels of the 48Ca-induced hot fusion reactions are predicted for the first time for future experiments.

  17. Impacts of the tensor couplings of ω and ρ mesons and Coulomb-exchange terms on superheavy nuclei and their relation to the symmetry energy

    Science.gov (United States)

    Liliani, N.; Nugraha, A. M.; Diningrum, J. P.; Sulaksono, A.

    2016-05-01

    We have studied the effects of tensor coupling of ω and ρ meson terms, the Coulomb exchange term in local density approximation, and various isoscalar-isovector coupling terms of relativistic mean-field model on the properties of nuclear matter, finite nuclei, and superheavy nuclei. We found that for the same fixed value of symmetry energy J or its slope L the presence of tensor coupling of ω and ρ meson terms and the Coulomb exchange term yields thicker neutron skin thickness of 208Pb. We also found that the roles of tensor coupling of ω and ρ meson terms, the Coulomb-exchange term in local density approximation, and various isoscalar-isovector coupling terms on the bulk properties of finite nuclei vary depending on the corresponding nucleus mass. However, on average, tensor coupling terms play a significant role in predicting the bulk properties of finite nuclei in a quite wide mass range, especially in binding energies. We also observed that for some particular nuclei, the corresponding experimental data of binding energies are rather less compatible with the presence of the Coulomb-exchange term in local density approximation and they tend to disfavor the presence of isoscalar-isovector coupling term with too-high Λ value. Furthermore, we have found that these terms influence the detail properties of 292120 superheavy nucleus such as binding energies, the magnitude of two-nucleon gaps, single-particle spectra, neutron densities, neutron skin thicknesses, and mean-square charge radii. However, the shell-closure predictions of 208Pb and 292120 nuclei are not affected by the presence of these terms.

  18. Spontaneous Fission and alpha -Decay Half-Lives of Superheavy Nuclei in Different Macroscopic Energy Models

    CERN Document Server

    Lojewski, Z; Pomorski, K

    2003-01-01

    Spontaneous fission half-lives (T sub s sub f) of the heaviest nuclei are calculated in the macroscopic-microscopic approach based on the deformed Woods-Saxon potential. Four different models of the macroscopic energy are examined and their influence on the results is discussed. The calculations of (T sub s sub f) are performed within WKB approximation. Multi-dimensional dynamical-programming method (MDP) is applied to minimize the action integral in a 3-dimensional space of deformation parameters describing the nuclear shape (beta sub 2 ,beta sub 4 ,beta sub 6).

  19. Neck Fragmentation in Fission and Quasifission of Heavy and Superheavy Nuclei

    Science.gov (United States)

    Rubchenya, V. A.; Trzaska, W. H.; Vardaci, E.

    The generalized approach is proposed for the ternary fission and the neck fragmentation of the dinuclear system formed in the heavy ion quasifission reactions. The light-charged-particles accompanied the fission and quasifission are the valuable probes for studies of the dynamics of the hyperdeformed nuclear configurations with neck. The developed model describes well the light-charged-particle emission probabilities and their mass distributions in the ternary fission of actinide nuclei. The model is also applied to analyze the double differential distributions of the protons and α-particles accompanied fragmentation in the reaction 86Kr + 206Pb at EKr = 500 and 600 MeV. It was found that the near scission emission multiplicities of α-particles are Mα NF = 0.025 ± 0.005 and 0.070 ± 0.005 at lower and higher energies, respectively. The neck emission of the protons was not detected.

  20. Cold reaction valleys in the radioactive decay of superheavy {sup 286}112, {sup 292}114, and {sup 296}116 nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Santhosh, K. P.; Sabina, S. [Kannur University, School of Pure and Applied Physics (India)

    2012-08-15

    Cold reaction valleys in the radioactive decay of superheavy nuclei {sup 286}112, {sup 292}114, and {sup 296}116 are studied taking Coulomb and Proximity Potential as the interacting barrier. It is found that in addition to alpha particle, {sup 8}Be, {sup 14}C, {sup 28}Mg, {sup 34}Si, {sup 50}Ca, etc. are optimal cases of cluster radioactivity since they lie in the cold valleys. Two other regions of deep minima centered on {sup 208}Pb and {sup 132}Sn are also found. Within our Coulomb and Proximity Potential Model half-life times and other characteristics such as barrier penetrability, decay constant for clusters ranging from alpha particle to {sup 68}Ni are calculated. The computed alpha half-lives match with the values calculated using Viola-Seaborg-Sobiczewski systematics. The clusters {sup 8}Be and {sup 14}C are found to be most probable for emission with T{sub 1/2} < 10{sup 30} s. The alpha-decay chains of the three superheavy nuclei are also studied. The computed alpha-decay half-lives are compared with the values predicted by Generalized Liquid Drop Model and they are found to match reasonably well.

  1. Neutrino Processes with Hot Nuclei in Supernovae

    Science.gov (United States)

    Dzhioev, A. A.; Vdovin, A. I.

    In this paper, we calculate cross sections for charged-current neutrino-nucleus processes occuring under presupernova conditions. To treat thermal effects we extend self-consistent Skyrme-QRPA calculations to finite temperature by using the formalism of thermo field dynamics. The numerical results are presented for the sample nuclei, $^{56}$Fe and $^{82}$Ge

  2. Impacts of the tensor couplings of $\\omega$ and $\\rho$ mesons and Coulomb exchange terms on super-heavy nuclei and their relation to symmetry energy

    CERN Document Server

    Liliani, N; Diningrum, J P; Sulaksono, A

    2016-01-01

    We have studied the effects of tensor coupling of $\\omega$ and $\\rho$ meson terms, Coulomb exchange term in local density approximation and various isoscalar-isovector coupling terms of relativistic mean field model on the properties of nuclear matter, finite nuclei, and super-heavy nuclei. We found that for the same fixed value of symmetry energy $J$ or its slope $L$ the presence of tensor coupling of $\\omega$ and $\\rho$ meson terms and Coulomb exchange term yields thicker neutron skin thickness of $^{208}$Pb. We also found that the roles of tensor coupling of $\\omega$ and $\\rho$ meson terms, Coulomb exchange term in local density approximation and various isoscalar-isovector coupling terms on the bulk properties of finite nuclei varies depending on the corresponding nucleus mass. However, on average, tensor coupling terms play a significant role in predicting the bulk properties of finite nuclei in a quite wide mass range especially in binding energies. We also observed that for some particular nuclei, the ...

  3. Inelastic neutrino scattering off hot nuclei in supernova environments

    CERN Document Server

    Dzhioev, Alan A; Wambach, J; Ponomarev, V Yu

    2014-01-01

    We study inelastic neutrino scattering off hot nuclei for temperatures relevant under supernova conditions. The method we use is based on the quasiparticle random phase approximation extended to finite temperatures within the thermo field dynamics (TQRPA). The method allows a transparent treatment of upward and downward transitions in hot nuclei, avoiding the application of Brink's hypothesis. For the sample nuclei $^{56}$Fe and $^{82}$Ge we perform a detailed analysis of thermal effects on the strength distributions of allowed Gamow-Teller (GT) transitions which dominate the scattering process at low neutrino energies. For $^{56}$Fe and $^{82}$Ge the finite temperature cross-sections are calculated by taking into account the contribution of allowed and forbidden transitions. The observed enhancement of the cross-section at low neutrino energies is explained by considering thermal effects on the GT strength. For $^{56}$Fe we compare the calculated cross-sections to those obtained earlier from a hybrid approac...

  4. Giant dipole resonance in hot rotating nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Chakrabarty, D.R. [Bhabha Atomic Research Centre, Nuclear Physics Division, Mumbai (India); Dinh Dang, N. [RIKEN, Nishina Centre for Accelerator-based Science, Saitama (Japan); VINATOM, Institute of Nuclear Science and Technique, Hanoi (Viet Nam); Datar, V.M. [Tata Institute of Fundamental Research, INO Cell, Mumbai (India)

    2016-05-15

    Over the last several decades, extensive experimental and theoretical work has been done on the giant dipole resonance (GDR) in excited nuclei covering a wide range of temperature (T), angular momentum (J) and nuclear mass. A reasonable stability of the GDR centroid energy and an increase of the GDR width with T (in the range∝1-3 MeV) and J are the two well-established results. Some experiments have indicated the saturation of the GDR width at high T. The gradual disappearance of the GDR vibration at much higher T has been observed. Experiments on the Jacobi transition and the GDR built on superdeformed shapes at high rotational frequencies have been reported in a few cases. Theoretical calculations on the damping of the collective dipole vibration, characterised by the GDR width, have been carried out within various models such as the thermal shape fluctuation model and the phonon damping model. These models offer different interpretations of the variation of the GDR width with T and J and have met with varying degrees of success in explaining the experimental data. In this review, the present experimental and theoretical status in this field is discussed along with the future outlook. The interesting phenomenon of the pre-equilibrium GDR excitation in nuclear reactions is briefly addressed. (orig.)

  5. Pairing and specific heat in hot nuclei

    CERN Document Server

    Gambacurta, Danilo; Sandulescu, Nicu

    2013-01-01

    The thermodynamics of pairing phase-transition in nuclei is studied in the canonical ensemble and treating the pairing correlations in a finite-temperature variation after projection BCS approach (FT-VAP). Due to the restoration of particle number conservation, the pairing gap and the specific heat calculated in the FT-VAP approach vary smoothly with the temperature, indicating a gradual transition from the superfluid to the normal phase, as expected in finite systems. We have checked that the predictions of the FT-VAP approach are very accurate when compared to the results obtained by an exact diagonalization of the pairing Hamiltonian. The influence of pairing correlations on specific heat is analysed for the isotopes $^{161,162}$Dy and $^{171,172}$Yb. It is shown that the FT-VAP approach, applied with a level density provided by mean field calculations and supplemented, at high energies, by the level density of the back-shifted Fermi gas model, can approximate reasonably well the main properties of specifi...

  6. Constrained caloric curves and phase transition for hot nuclei

    CERN Document Server

    Borderie, Bernard; Rivet, M F; Raduta, Ad R; Ademard, G; Bonnet, E; Bougault, R; Chbihi, A; Frankland, J D; Galichet, E; Gruyer, D; Guinet, D; Lautesse, P; Neindre, N Le; Lopez, O; Marini, P; Parlog, M; Pawlowski, P; Rosato, E; Roy, R; Vigilante, M

    2013-01-01

    Simulations based on experimental data obtained from multifragmenting quasi-fused nuclei produced in central $^{129}$Xe + $^{nat}$Sn collisions have been used to deduce event by event freeze-out properties in the thermal excitation energy range 4-12 AMeV [Nucl. Phys. A809 (2008) 111]. From these properties and the temperatures deduced from proton transverse momentum fluctuations, constrained caloric curves have been built. At constant average volumes caloric curves exhibit a monotonic behaviour whereas for constrained pressures a backbending is observed. Such results support the existence of a first order phase transition for hot nuclei.

  7. Probing the hot zone of colliding nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Elmer, R.Aa.

    1995-11-01

    The hot zone created in intermediate energy heavy ion collisions has been studied. At energies between 20 A MeV and 300 A MeV the nuclear emulsion technique has been used to achieve a full 4 pi identification and momentum determination of all charged fragments, enabling a strict selection of central events based on multiplicity and the energy flow tensor. In connection with this a CCD-based track identification system has been developed, specially designed for charge identification of intermediate-mass fragments. The CCD-camera is connected to an image processing card in a microcomputer where the width of the track is determined by profile measurements on the pixel level. The results point to a presence of radial flow in central {sup 36}Ar + AgBr collisions at 65 A MeV, but not in {sup 16}O + AgBr collisions at 210 A MeV. At energies between 0.8 to 1.8 A GeV mesons produced in symmetric Ne + NaF, Ni + Ni and Au + Au, have been measured by plastic scintillator counter telescopes. The mass and angular dependence of the subthreshold production of kaons at a laboratory energy of 1.0 A GeV have been systematically extracted from three different experiment periods at GSI, Darmstadt. The results point to the presence of rescattering of kaons in the dense nuclear environment, thus increasing the cross section at large angles. More speculatively, an anisotropy in the production process could be conjectured. 61 refs, 15 figs.

  8. Study of the influence of the shell correction energy on the nuclear reactions leading to the region of the superheavy nuclei; Etude de l'influence de l'energie de correction de couches sur les reactions nucleaires menant a la region des noyaux superlourds

    Energy Technology Data Exchange (ETDEWEB)

    Marchix, A

    2007-11-15

    The aim of this work is to study the influence of shell correction energy on the deexcitation of superheavy nuclei. For that purpose, a new statistical code, called Kewpie2, which is based on an original algorithm allowing to have access to very weak probabilities, was developed. The results obtained with Kewpie2 have been compared to the experimental data on residue cross sections obtained by cold fusion (Z=108 to Z=113) and by hot fusion (Z=112, Z=114 and Z=116), as well as data on fission times (Z=114, Z=120 and Z=126). Constraints on the microscopic structure of the studied nuclei have been obtained by means of the shell correction energy. By adjusting the intrinsic parameters of the models of fusion in order to reproduce the data on the fusion cross sections, this study shows the necessity of decreasing very strongly the shell correction energy predicted by the calculations of Moller and Nix, during the study of the residues cross sections as well for the nuclei produced by cold fusion as by hot fusion. On the other hand, during the confrontation of the results of Kewpie2 to the data on mean fission times, it is rather advisable to increase it. A shift of the proton shell closure predicted for Z=114 by the calculations of Moller and Nix towards larger Z would allow to explain these opposite conclusions. In this thesis, we also have shown the significant influence of the inclusion of isomeric states on fission times for the superheavy nuclei. (author)

  9. Exotic decay of hot rotating nuclei near proton drip line

    Science.gov (United States)

    Ray, J.; Datta Pramanik, U.; Bhowmik, R. K.; Ray, I.; Rahaman, A.; Chakraborty, A.; Chakraborty, S.; Garg, R.; Goyal, S.; Ganguly, S.; Kumar, S.; Mandal, S.; Mukherjee, B.; Mukherjee, P.; Muralithar, S.; Negi, D.; Saxena, M.; Selvakumar, K.; Singh, P.; Singh, A. K.; Singh, R. P.

    2014-03-01

    Hot and rotating exotic 124Ce nucleus near proton drip line has been populated through fusion evaporation reaction of 32S and 92Mo. This exotic nucleus was de-excited by evaporating p, n, α and/or light nuclei etc and several exotic nuclei have been populated. The experimentally obtained relative population of those exotic nuclei have been compared with the statistical model calculation. Agreement between experimental and statistical model calculation have been observed for most of the evaporation channels. Huge enhancement in comparison to statistical model calculation have been observed fora few channels related to multiple proton evaporation which could not be explained by using default and modified input parameters in statistical calculation.

  10. Analytical expression for the α-decay half-life and understanding the data including very long life-times and superheavy nuclei

    Science.gov (United States)

    Sahu, Basudeb

    2008-10-01

    An analytically solvable composite potential that can closely reproduce the combined potential of an α+nucleus system consisting of attractive nuclear and repulsive electrostatic potentials is developed. The exact s-wave solution of the Schrödinger equation with this potential in the interior region and the outside Coulomb wave function are used to give a heuristic expression for the width or half-life of the quasibound state at the accurately determined resonance energy, called the Q value of the decaying system. By using the fact that for a relatively low resonance energy, the quasibound state wave function is quite similar to the bound state wave function where the amplitude of the wave function in the interaction region is very large as compared to the amplitude outside, the resonance energy could easily be calculated from the variation of relative probability densities of inside and outside waves as a function of energy. By considering recent α-decay systems, the applicability of the model is demonstrated with excellent explanations being found for the experimental data of Q values and half-lives of a vast range of masses including superheavy nuclei and nuclei with very long lifetimes (of order 1022 s). Throughout the application, by simply varying the value of a single potential parameter describing the flatness of the barrier, we obtain successful results in cases with as many as 70 pairs of α+daughter nucleus systems.

  11. Alpha decay properties of heavy and superheavy elements

    Indian Academy of Sciences (India)

    G M Carmel Vigila Bai; J Umai Parvathiy

    2015-01-01

    Analysing accurately the lifetimes of -decay chains is an important tool to detect and study the properties of superheavy nuclei. 48Ca is used in the synthesis of superheavy nuclei = 106−118 at Dubna. The experimental work of 48Ca projectiles at Dubna has given an opportunity to study the superheavy element (SHE). Here, the -decay properties for = 106–118 are evaluated using our CYE model and are compared with the available experimental and theoretical values.

  12. Inelastic neutrino scattering off hot nuclei in supernova environments

    Science.gov (United States)

    Dzhioev, Alan A.; Vdovin, A. I.; Wambach, J.; Ponomarev, V. Yu.

    2014-03-01

    We study inelastic neutrino scattering off hot nuclei for temperatures relevant under supernova conditions. The method we use is based on the quasiparticle random phase approximation extended to finite temperatures within the thermo-field dynamics. The method allows a transparent treatment of upward and downward transitions in hot nuclei, avoiding the application of Brink's hypothesis. For the sample nuclei 56Fe and 82Ge we perform a detailed analysis of thermal effects on the strength distributions of allowed Gamow-Teller (GT) transitions which dominate the scattering process at low neutrino energies. For 56Fe and 82Ge the finite temperature cross sections are calculated by taking into account the contribution of allowed and forbidden transitions. The observed enhancement of the cross section at low neutrino energies is explained by considering thermal effects on the GT strength. For 56Fe we compare the calculated cross sections to those obtained earlier from a hybrid approach that combines large-scale shell-model and RPA calculations.

  13. Neutrino absorption by hot nuclei in supernova environments

    CERN Document Server

    Dzhioev, Alan A; Wambach, J

    2015-01-01

    Using the thermal quasiparticle random phase approximation, we study the process of neutrino and antineutrino capture on hot nuclei in supernova environments. For the sample nuclei $^{56}$Fe and $^{82}$Ge we perform a detailed analysis of thermal effects on the strength distribution of allowed Gamow-Teller transitions which dominate low-energy charged-current neutrino reactions. The finite temperature cross sections are calculated taking into account the contributions of both allowed and forbidden transitions. The enhancement of the low-energy cross sections is explained by considering thermal effects on the GT$_\\pm$ strength. For $^{56}$Fe we compare the calculated finite-temperature cross sections with those obtained from large-scale shell-model calculations.

  14. Neutrino absorption by hot nuclei in supernova environments

    Science.gov (United States)

    Dzhioev, Alan A.; Vdovin, A. I.; Wambach, J.

    2015-10-01

    Using the thermal quasiparticle random-phase approximation, we study the process of neutrino and antineutrino capture on hot nuclei in supernova environments. For the sample nuclei 56Fe and 82Ge we perform a detailed analysis of thermal effects on the strength distribution of allowed Gamow-Teller (GT) transitions which dominate low-energy charged-current neutrino reactions. The finite-temperature cross sections are calculated taking into account the contributions of both allowed and forbidden transitions. The enhancement of the low-energy cross sections is explained by considering thermal effects on the GT± strength. For 56Fe we compare the calculated finite-temperature cross sections with those obtained from large-scale shell-model calculations.

  15. Spectroscopy of very heavy nuclei with a view to study super-heavy nuclei; Spectroscopie de noyaux tres lourds en vue de l'etude des noyaux super-lourds

    Energy Technology Data Exchange (ETDEWEB)

    Khalfallah, F

    2007-08-15

    Within the recent years, the spectroscopic study of single particle orbitals of very heavy elements (VHE) has become possible with the development of increasingly efficient experimental setups. This allows us, through nuclear deformation, to access with these deformed nuclei to orbitals situated around the Fermi level in the spherical superheavy elements (SHE) and learn more about the nuclear structure of these nuclei. The aim of this work is the spectroscopic studies of heavy and very heavy elements. Because of the experimental difficulties associated with the fusion reactions in the VHE region, a detailed optimization studies is essential. Simulation of energy loss and angular straggling of these nuclei due to the interaction in the target and to neutron's evaporation was carried out and allowed us to optimize the angular acceptance of the separators according to the target thickness. An extensive survey and exploration in the VHE region was also conducted on the basis of cross section's systematics in the literature and simulations carried out using the statistical code Hivap. In this framework, the possible extension of the range of validity of a set of Hivap parameters was investigated. This work has enabled us to prepare a list of experiments of interest for the production of very heavy nuclei. In this thesis, our work was concentrated on the spectroscopy of the nuclei No{sup 256} et Rf{sup 256} for which two experimental proposals were accepted. The octupole deformations predicted in the actinides region is studied in another part of this thesis, a part witch is dedicated to the gamma spectroscopy of Pa{sup 223}. The data from a new experiment carried out using the Jurogam-Ritu-Great setup are analysed and compared to previous results. They confirm the octupole deformed shape in this nucleus. (author)

  16. Predictions on the alpha decay half lives of Superheavy nuclei with Z = 113 in the range 255 l.e. A l.e. 314

    CERN Document Server

    Santhosh, K P; Nithya, C; Priyanka, B

    2016-01-01

    An intense study of the alpha decay properties of the isotopes of superheavy element Z=113 have been performed within the Coulomb and proximity potential model for deformed nuclei (CPPMDN) within the wide range 255 l.e. A l.e. 314. The predicted alpha decay half lives of $^{278}$113 and $^{282}$113 and the alpha half lives of their decay products are in good agreement with the experimental data. 6{\\alpha) chains and 4{\\alpha} chains predicted respectively for $^{278}$113 and $^{282}$113 are in agreement with the experimental observation. Our study shows that the isotopes in the mass range 278 l.e. A l.e. 286 will survive fission and can be synthesized and detected in the laboratory via alpha decay. In our study, we have predicted 6{\\alpha} chains from $^{279}$113, 4{\\alpha} chains from $^{286}$113, 3{\\alpha} chains from $^{280,281,283}$113, 2{\\alpha} chains from $^{284}$113 and 1{\\alpha} chain from $^{285}$113. We hope that these predictions will be a guideline for future experimental investigations.

  17. Predictions on the alpha decay half lives of superheavy nuclei with Z = 113 in the range 255 ≤ A ≤ 314

    Science.gov (United States)

    Santhosh, K. P.; Augustine, A.; Nithya, C.; Priyanka, B.

    2016-07-01

    An intense study of the alpha decay properties of the isotopes on superheavy element with Z = 113 has been performed within the Coulomb and proximity potential model for deformed nuclei (CPPMDN) within the wide range 255 ≤ A ≤ 314. The predicted alpha decay half lives of 278113 and 282113 and the alpha half lives of their decay products are in good agreement with the experimental data. 6α chains and 4α chains predicted respectively for 278113 and 282113 are in agreement with the experimental observation. Our study shows that the isotopes in the mass range 278 ≤ A ≤ 286 will survive fission and can be synthesized and detected in the laboratory via alpha decay. In our study, we have predicted 6α chains from 279113, 4α chains from 286113, 3α chains from 280,281,283113, 2α chains from 284113 and 1α chain from 285113. We hope that these predictions will be a guideline for future experimental investigations.

  18. Decay of Hot Nuclei at Low Spins Produced by Antiproton-Annihilation in Heavy Nuclei

    CERN Multimedia

    2002-01-01

    % PS208 \\\\ \\\\ The objective of the experiment is to study (i) the thermal excitation energy distribution of antiproton-induced reactions in heavy nuclei and (ii) the decay properties of hot nuclei at low spins via evaporation, multifragmentation and fission as a function of excitation energy. The experimental set-up consists of 4-$\\pi$ detectors: the Berlin Neutron Ball~(BNB) which is a spherical shell of gadolinium-loaded scintillator liquid with an inner and outer diameter of 40 and 160~cm, respectively. This detector counts the number of evaporated neutrons in each reaction. Inside BNB there is a 4-$\\pi$ silicon ball~(BSIB) with a diameter of 20~cm consisting of 162 detectors which measure energy and multiplicity of all emitted charged nuclear particles. The particles are identified via time of flight, energy and pulse shape correlations.

  19. A multi-reflection time-of-flight mass spectrograph for short-lived and super-heavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Schury, P., E-mail: schury@riken.jp [University of Tsukuba, Institute of Physics, Tsukuba City, Ibaraki (Japan); RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); New Mexico State University, Dept. of Chem. and BioChem., Las Cruces, NM (United States); Wada, M. [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Ito, Y. [University of Tsukuba, Institute of Physics, Tsukuba City, Ibaraki (Japan); RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Naimi, S.; Sonoda, T. [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Mita, H. [University of Tsukuba, Institute of Physics, Tsukuba City, Ibaraki (Japan); RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Takamine, A. [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Aoyama Gakuin University, Sagamihara, Kanagawa (Japan); Okada, K. [Sophia University, Chiyoda-ku, Tokyo (Japan); Wollnik, H. [New Mexico State University, Dept. of Chem. and BioChem., Las Cruces, NM (United States); Chon, S. [KEK, Tsukuba, Ibaraki (Japan); Haba, H.; Kaji, D. [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Koura, H. [Japan Atomic Energy Research Institute, Ibaraki (Japan); Miyatake, H. [KEK, Tsukuba, Ibaraki (Japan); Morimoto, K.; Morita, K. [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Ozawa, A. [University of Tsukuba, Institute of Physics, Tsukuba City, Ibaraki (Japan)

    2013-12-15

    Highlights: • Demonstrated very fast mass measurements with a multi-reflection time of flight mass spectrograph. • Mass resolving power of R{sub m}≈150,000 was achieved in 1.2-ms for A/q=39 ions. • Mass precision of (δm)/m =7.7×10{sup 8} was demonstrated for {sup 40}Ca{sub +}. • Effects of thermal and voltage instabilities are described. • Effects of thermal and voltage instabilities are described. -- Abstract: A multi-reflection time-of-flight (MRTOF) mass spectrograph has been implemented at RIKEN to provide high-precision mass measurements of very short-lived nuclei. Of particular interest are mass measurements of r-process nuclei and trans-uranium nuclei. In such nuclei, the MRTOF can perform on par with or better than traditional Penning trap systems. We demonstrate that the MRTOF-MS is capable of accurately attaining relative mass precision of δm/m<10{sup -7} and describe it’s utility with heavy, short-lived nuclei.

  20. On the TFD treatment of collective vibrations in hot nuclei

    CERN Document Server

    Dzhioev, Alan A

    2008-01-01

    The approach in a theory of collective excitations in hot nuclei exploring the formalism of thermo field dynamics and the model Hamiltonian consisting of a mean field, the BCS paring interaction and long-range particle-hole effective forces is reexamined. In contrast with earlier studies it is found that a wave function of a thermal phonon is depended not only on the Fermi-Dirac thermal occupation numbers of Bogoliubov quasiparticles consisting the phonon but on the Bose thermal occupation numbers of the phonon as well. This strongly affects a thermal phonon couplings due to renormalizing of a phonon-phonon interaction and enlarging the number of thermal two-phonon configurations coupled with one-phonon ones. Moreover, it is shown that the formulation of the double tilde conjugation rule for fermions proposed by I.Ojima is more appropriate in the context of the present study than the original one by H.Umezawa and coworkers.

  1. Systematic Calculation on Ground State Properties of Even-even Superheavy Nuclei Using Relativistic Mean Field Theory

    Institute of Scientific and Technical Information of China (English)

    ZhangHongfei; ZuoWei; SoojaeRenIm; ZhouXiaohong; LiJunqing

    2003-01-01

    In recent years the discovery of Super Heavy Element (SHE) with atomic number Z=108~116 has opened up a new era of research in nuclear physics, however, the extreme difficulties to synthesize SHE greatly restrict the experimental studies on it, so that the theoretical studies are very important. The Relativistic Mean Field theory (RMF) is proved to be a simple and successful theory due to its great success in describing the bulk properties at the β-stable valley, as well as nuclei far from the β-stable line, and gives good predictions for nuclei far beyond the end of the known periodic table. In the framework of RMF we have calculated the properties on SHN such as the binding energy, the deformation, single and double neutron separation energy, and the a-decay half-life and so on for nuclei Z=108~114 and N=156~190. The axial deformations considered by using the expansion of harmonic oscillator basis. The Lagrangian wc have used is as the following form:

  2. Study of the properties of the superheavy nuclei Z = 117 produced in the 249Bk + 48Ca reaction

    Science.gov (United States)

    Oganessian, Yu. Ts.; Abdullin, F. Sh.; Alexander, C.; Binder, J.; Boll, R. A.; Dmitriev, S. N.; Ezold, J.; Felker, K.; Gostic, J. M.; Grzywacz, R. K.; Hamilton, J. H.; Henderson, R. A.; Itkis, M. G.; Miernik, K.; Miller, D.; Moody, K. J.; Polyakov, A. N.; Ramayya, A. V.; Roberto, J. B.; Ryabinin, M. A.; Rykaczewski, K. P.; Sagaidak, R. N.; Shaughnessy, D. A.; Shirokovsky, I. V.; Shumeiko, M. V.; Stoyer, M. A.; Stoyer, N. J.; Subbotin, V. G.; Sukhov, A. M.; Tsyganov, Yu. S.; Utyonkov, V. K.; Voinov, A. A.; Vostokin, G. K.

    2014-03-01

    The reaction of 249Bk with 48Ca have been reinvestigated to provide new evidence for the discovery of element 117 on a larger number of events. The experiments were performed at five projectile energies and with a total beam dose of 48Ca of about 4.6×1019. Two isotopes 293,294117 were synthesized in the 249Bk+48Ca reaction, providing excitation functions and α-decay spectra of the produced isotopes that establishes these nuclei to be the products of the 4n- and 3n-evaporation channels, respectively. Decay properties of 293,294117 and of all the daughter products agree with the data of the experiment in which these nuclei were synthesized for the first time in 2010. The new 289115 events, populated by α decay of 293117, demonstrate the same decay properties as those observed for 289115 produced in the 243Am(48Ca,2n) reaction thus providing crossbombardment evidence. In addition, a single decay of 294118 was observed from the reaction with 249Cf - a result of the in-growth of 249Cf in the 249Bk target.

  3. Study of the properties of the superheavy nuclei Z = 117 produced in the 249Bk + 48Ca reaction

    Directory of Open Access Journals (Sweden)

    Oganessian Yu. Ts.

    2014-03-01

    Full Text Available The reaction of 249Bk with 48Ca have been reinvestigated to provide new evidence for the discovery of element 117 on a larger number of events. The experiments were performed at five projectile energies and with a total beam dose of 48Ca of about 4.6×1019. Two isotopes 293,294117 were synthesized in the 249Bk+48Ca reaction, providing excitation functions and α-decay spectra of the produced isotopes that establishes these nuclei to be the products of the 4n- and 3n-evaporation channels, respectively. Decay properties of 293,294117 and of all the daughter products agree with the data of the experiment in which these nuclei were synthesized for the first time in 2010. The new 289115 events, populated by α decay of 293117, demonstrate the same decay properties as those observed for 289115 produced in the 243Am(48Ca,2n reaction thus providing crossbombardment evidence. In addition, a single decay of 294118 was observed from the reaction with 249Cf – a result of the in-growth of 249Cf in the 249Bk target.

  4. Dynamics in Production of Superheavy Nuclei in Low-energy Heavy-ion Collisions%低能重离子碰撞产生超重核动力学机制

    Institute of Scientific and Technical Information of China (English)

    冯兆庆; 靳根明; 李君清

    2011-01-01

    总结了描述重系统碰撞形成超重核的主要理论模型进展.基于两类反应机制,即熔合蒸发反应和大质量阻尼反应,对产生超重核的物理过程进行了讨论.分析了超重核形成过程中碰撞系统的俘获、复合核的形成及蒸发退激描述存在的问题.基于双核模型分析了合成冷熔合反应和48Ca诱发全熔合反应之间的超重新核素的可能性.利用锕系核碰撞的转移反应产生子壳N=162附件丰中子重核的可行性,研究了壳效应对丰中子核素产生的影响.进一步讨论了将来基于丰中子强流放射性束合成超重核的可行性.%We present a review of the recent progress of theoretical models on the description of the superheavy nucleus formation in heavy ion collisions.Two sorts of reactions that are the fusionevaporation mechanism and the massive damped collisions toproduce superheavy nuclei are discussed.Problems and further improvements of the capture of colliding partners,the formation of compound nucleus and the de-excitation process are pointed out.Possible combinations for the synthesis of the superheavy nuclei in between the products of the cold fusion and "Ca induced reactions are proposed by the calculations based on thedinuclear system model and also compared with other approaches.The synthesis of neutron-rich heavy isotopes near sub-shell closure N=162 via transfer reactions in the damped collisions of two actinides and the influence of shell closure on the production of heavy isotopes are investigated.Prospective possibility to reach superheavy nuclei near N=184 via neutron-rich radioactive beams of high intensity in the future is discussed.

  5. Basic non-linear effects in silicon radiation detector in detection of highly ionizing particles: registration of ultra rare events of superheavy nuclei in the long-term experiments

    CERN Document Server

    Tsyganov, Y S

    2015-01-01

    Sources of non-linear response of PIPS detector, when detecting highly ionizing particles like recoils (EVR), fission fragments and heavy ions, including formation of large pulse-height defect (PHD) are considered. An analytical formula to calculate the recombination component of EVR PHD is proposed on the base of surface recombination model with some empirical correction. PC-based simulation code for generating the spectrum of the measured recoil signal amplitudes of the heavy implanted nuclei is presented. The simulated spectra are compared with the experimental ones for the different facilities: the Dubna Gas Filled Recoil Separator (DGFRS), SHIP and RIKEN gas-filled separator. After the short reviewing of the detection system of the DGFRS, is considered the real-time matrix algorithm application aimed to the radical background suppression in the complete-fusion heavy-ion induced nuclear reactions. Typical examples of application in the long term experiments aimed to the synthesis of superheavy elements Z=...

  6. Inclusion of temperature dependent shell corrections in Landau theory for hot rotating nuclei

    Indian Academy of Sciences (India)

    G Shanmugam; P Arumugam

    2001-07-01

    Landau theory used for studying hot rotating nuclei usually uses zero temperature Strutinsky smoothed total energy for the temperature dependent shell corrections. This is replaced in this work by the temperature dependent Strutinsky smoothed free energy. Our results show that this replacement has only marginal effect for temperatures greater than 1 MeV but plays significant role at lower temperatures.

  7. Production cross sections of the superheavy nucleus 117 based on the dinuclear system model

    Institute of Scientific and Technical Information of China (English)

    ZHAO Wei-Juan; ZHANG Yong-Qi; WANG Hua-Lei; SONG Li-Tao; LI Lu-Lu

    2010-01-01

    Within the framework of the dinuclear system model,the capture of two colliding nuclei,and the formation and de-excitation process of a compound nucleus are described by using an empirical coupled channel model,solving the master equation numerically and the statistical evaporation model,respectively.In the process of heavy-ion capture and fusion to synthesize superheavy nuclei,the barrier distribution func-tion is introduced and averaging collision orientations are considered.Based on this model,the production cross sections of the cold fusion system 76-82Se+209Bi and the hot fusion systems 55Mn+238U,51V-+244Pu,59 Co+232 Th,48 Ca+247-249 Bk and 45 Sc+246-248 Cm are calculated.The isotopic dependence of the largest production cross sections is analyzed briefly,and the optimal projectile-target combination and excitation energy of the ln-4n evaporation channels are proposed.It is shown that the hot fusion systems 48Ca+247 249Bk in the3n evaporation channels and 45Sc+248Cm in the 2n-4n channels are optimal for synthesizing the superheavy element 117.

  8. Symmetric and asymmetric ternary fission of hot nuclei

    Science.gov (United States)

    Siwek-Wilczynska, K.; Wilczynski, J.; Leegte, H. K. W.; Siemssen, R. H.; Wilschut, H. W.; Grotowski, K.; Panasiewicz, A.; Sosin, Z.; Wieloch, A.

    1993-07-01

    Emission of α particles accompanying fusion-fission processes in the 40Ar +232Th reaction at E(40Ar) = 365 MeV was studied in a wide range of in-fission-plane and out-of-plane angles. The exact determination of the emission angles of both fission fragments combined with the time-of-flight measurements allowed us to reconstruct the complete kinematics of each ternary event. The coincident energy spectra of α particles were analyzed by using predictions of the energy spectra of the statistical code cascade . The analysis clearly demonstrates emission from the composite system prior to fission, emission from fully accelerated fragments after fission, and also emission during scission. The analysis is presented for both symmetric and asymmetric fission. The results have been analyzed using a time-dependent statistical decay code and confronted with dynamical calculations based on a classical one-body dissipation model. The observed near-scission emission is consistent with evaporation from a dinuclear system just before scission and evaporation from separated fragments just after scission. The analysis suggests that the time scale of fission of the hot composite systems is long (about 7×10-20 s) and the motion during the descent to scission almost completely damped.

  9. Quasifission in heavy and superheavy element formation reactions

    Science.gov (United States)

    Hinde, D. J.; Dasgupta, M.; Jeung, D. Y.; Mohanto, G.; Prasad, E.; Simenel, C.; Walshe, J.; Wahkle, A.; Williams, E.; Carter, I. P.; Cook, K. J.; Kalkal, Sunil; Rafferty, D. C.; Rietz, R. du; Simpson, E. C.; David, H. M.; Düllmann, Ch. E.; Khuyagbaatar, J.

    2016-12-01

    Superheavy elements are created in the laboratory by the fusion of two heavy nuclei. The large Coulomb repulsion that makes superheavy elements decay also makes the fusion process that forms them very unlikely. Instead, after sticking together for a short time, the two nuclei usually come apart, in a process called quasifission. Mass-angle distributions give the most direct information on the characteristics and time scales of quasifission. A systematic study of carefully chosen mass-angle distributions has provided information on the global trends of quasifission. Large deviations from these systematics reveal the major role played by the nuclear structure of the two colliding nuclei in determining the reaction outcome, and thus implicitly in hindering or favouring superheavy element production.

  10. Production mechanism of hot nuclei in violent collisions in the Fermi energy domain

    Science.gov (United States)

    Veselsky, M.

    2002-07-01

    A production mechanism of highly excited nuclei formed in violent collisions in the Fermi energy domain is investigated. The collision of two nuclei is decomposed into several stages which are treated separately. Simplified exciton concept is used for the description of pre-equilibrium emission. A modified spectator-participant scenario is used where motion along classical Coulomb trajectories is assumed. The participant and one of the spectator zones undergo incomplete fusion. Excitation energies of both cold and hot fragment are determined. Results of the calculation are compared to recent experimental data in the Fermi energy domain. Data on hot projectile-like, mid-velocity and fusion-like sources are described consistently. Geometric aspects of pre-equilibrium emission are revealed. Explanations to previously unexplained experimental phenomena are given. Energy deposited into non-thermal degrees of freedom is estimated.

  11. The Superheavy Elements and Anti-Gravity

    Science.gov (United States)

    Anastasovski, Petar K.

    2004-02-01

    The essence of any propulsion concept is to overcome gravity. Anti-gravity is a natural means to achieve this. Thus, the technology to pursue anti-gravity, by using superheavy elements, may provide a new propulsion paradigm. The theory of superluminal relativity provides a hypothesis for existence of elements with atomic number up to Z = 145, some of which may possess anti-gravity properties. Analysis results show that curved space-time exists demonstrating both gravitic and anti-gravitic properties not only around nuclei but inside the nuclei as well. Two groups of elements (Z Hawking, in honour of Stephen W. Hawking.

  12. Extensions of Natural Radioactivity to 4th-Type and of the Periodic Table to Super-heavy Nuclei: Contribution of Raj K Gupta to Cold Nuclear Phenomena

    OpenAIRE

    BirBikram Singh; Sushil Kumar; Sharma, Manoj K.; S K Patra

    2014-01-01

    We have studied here the contribution of Indian Scientists associated with Prof. Raj K. Gupta to cold nuclear phenomena during the last almost four decades, which led to the discovery of fourth kind of natural radioactivity (also known as Cluster Radioactivity, CR) and to the extension of periodic table to super heavy nuclei. It is exclusively pointed out how the Quantum Mechanical Fragmentation Theory (QMFT) advanced by Prof. Raj K. Gupta and Collaborators led to the disc...

  13. Production mechanism of hot nuclei in violent collisions in the Fermi energy domain

    CERN Document Server

    Veselsky, M

    2002-01-01

    A production mechanism of highly excited nuclei formed in violent collisions in the Fermi energy domain is investigated. Collision of two nuclei is decomposed into several stages which are treated separately. A simple phenomenological approach based on the exciton concept is used for the description of pre-equilibrium emission. For violent collisions, a modified spectator-participant scenario is used where relative motion along the classical Coulomb trajectories is assumed. A simple approach is used for description of the incomplete fusion of the participant and one of the spectator zones. Excitation energies of both fragments are determined. Results of the calculation are compared to wide range of recent experimental nuclear reaction data in the Fermi energy domain. Geometric aspects of pre-equilibrium emission are revealed. Properties of hot projectile-like, mid-velocity and fusion-like sources are discussed. An adequate overall agreement between experiment and calculation is obtained.

  14. Spectroscopy of superheavy quasimolecules

    Energy Technology Data Exchange (ETDEWEB)

    Verma, P. [Gesellschaft fuer Schwerionenforschung (GSI), D-64291 Darmstadt (Germany) and Vaish College, Rohtak-124001 (India) and Jamia Millia Islamia, New Delhi-110025 (India)]. E-mail: p.verma@gsi.de; Mokler, P.H. [Gesellschaft fuer Schwerionenforschung (GSI), D-64291 Darmstadt (Germany); J-Liebig University, D-35392 Giessen (Germany); Braeuning-Demian, A. [Gesellschaft fuer Schwerionenforschung (GSI), D-64291 Darmstadt (Germany); Kozhuharov, C. [Gesellschaft fuer Schwerionenforschung (GSI), D-64291 Darmstadt (Germany); Braeuning, H. [J-Liebig University, D-35392 Giessen (Germany); Bosch, F. [Gesellschaft fuer Schwerionenforschung (GSI), D-64291 Darmstadt (Germany); Liesen, D. [Gesellschaft fuer Schwerionenforschung (GSI), D-64291 Darmstadt (Germany); Stoehlker, T. [Gesellschaft fuer Schwerionenforschung (GSI), D-64291 Darmstadt (Germany); Hagmann, S. [J-W-Goethe University, D-60486 Frankfurt (Germany); Chatterjee, S. [Gesellschaft fuer Schwerionenforschung (GSI), D-64291 Darmstadt (Germany); Gumberidze, A. [Gesellschaft fuer Schwerionenforschung (GSI), D-64291 Darmstadt (Germany); Reuschl, R. [J-W-Goethe University, D-60486 Frankfurt (Germany); Schoeffler, M. [J-W-Goethe University, D-60486 Frankfurt (Germany); Spillmann, U. [Gesellschaft fuer Schwerionenforschung (GSI), D-64291 Darmstadt (Germany); Orsic Muthig, A. [Gesellschaft fuer Schwerionenforschung (GSI), D-64291 Darmstadt (Germany); Tachenov, S. [Gesellschaft fuer Schwerionenforschung (GSI), D-64291 Darmstadt (Germany); Stachura, Z. [Institute for Nuclear Physics, PL-31342 Cracow (Poland); Wahab, M.A. [Jamia Millia Islamia, New Delhi-110025 (India)

    2006-11-15

    Superheavy quasimolecules are formed transiently during heavy-ion heavy-atom collisions at moderate collision velocities. Using highly charged projectiles, couplings in the inner-most shells of the quasimolecule can be probed. The present investigation of 69 MeV u{sup -1} Bi {sup q+}-ions (q=77, 81 and 82) on thin Au targets was aimed to determine the role of prior-to-collision inner shell vacancy in a superheavy quasiadiabatic collision. The possibility of using very thin solid targets for probing such collisions was investigated and the interaction distances for the inner-shell couplings were calculated.

  15. The meaning of the UHECR Hot Spots: A Light Nuclei Nearby Astronomy

    CERN Document Server

    Fargion, Daniele

    2014-01-01

    We update all the recent UHECR events reported by AUGER, Telescope Array as well as by AGASA in common coordinate maps. We confirm our earliest (2008-2013) model where UHECR are mostly light nuclei (He,Be,B), explaining the Virgo absence and confirming M82 as the main source of North TA Hot Spot. Many more sources , as NGC 253 and galactic ones, are possibly source of most of the 376 UHECR events. Several correlated map, already considered in recent years, are shown with all the events

  16. Extensions of Natural Radioactivity to 4th-Type and of the Periodic Table to Super-heavy Nuclei: Contribution of Raj K Gupta to Cold Nuclear Phenomena

    Directory of Open Access Journals (Sweden)

    BirBikram Singh

    2014-02-01

    Full Text Available We have studied here the contribution of Indian Scientists associated with Prof. Raj K. Gupta to cold nuclear phenomena during the last almost four decades, which led to the discovery of fourth kind of natural radioactivity (also known as Cluster Radioactivity, CR and to the extension of periodic table to super heavy nuclei. It is exclusively pointed out how the Quantum Mechanical Fragmentation Theory (QMFT advanced by Prof. Raj K. Gupta and Collaborators led to the discovery of unique phenomenon of CR along with the predictions leading to the synthesis of super heavy elements. We have also mentioned the development of dynamical theories based on QMFT, the Preformed Cluster Model(PCM and the dynamical cluster-decay model (DCM, to study the ground and excited state decays of nuclei, respectively, by Gupta and Collaborators. It is matter of great honor and pride for us to bring out this study to enthuse the young researchers to come up with novel ideas and have inspiration from the scientific contributions of Prof. Raj K. Gupta who is coincidentally celebrating his platinum jubilee birthday anniversary this year.

  17. Superheavy elements and decay properties

    Indian Academy of Sciences (India)

    K P Santhosh

    2015-09-01

    The decay properties of the isotopes of = 115, 117, 118 and 119 have been extensively investigated, focussing on the newly synthesized isotopes within the Coulomb and proximity potential model for deformed nuclei (CPPMDN). The half-lives have also been evaluated using the Viola–Seaborg systematic (VSS) and the analytical formulae of Royer and it can be seen that our calculated values match well with these theoretical values. The mode of decay of these isotopes has also been studied by calculating the spontaneous fission half-lives. Thus, we have predicted 4 chains from 287115, 3 chains from 288115, 3 chains from 293117, 4 chains from 294117 and 3 chains from 294118 and, it can be seen that our predictions on the decay chains also match well with the experimental observations. The study on = 119 has predicted six consistent chains from 292−295119, 5 chains from 296119, 4 chains from 297119 and 3 chains from 298,299119. Thus, through our study on isotopes of = 115, 117, 118 and 119 superheavy nuclei, we could predict the range of isotopes that may be detectable using decay and we hope that the findings on the isotopes of = 119 will provide a new guide for future experiments.

  18. Calculation of decay half-lives for superheavy elements using the double folding model

    Institute of Scientific and Technical Information of China (English)

    ZHANG Gao-Long; LE Xiao-Yun

    2009-01-01

    α decay half-lives of some new synthesized superheavy elements, possibly synthesized superheavy elements and decay products are calculated theoretically within the WKB approximation by using microscopic m-nucleus interaction potentials. These nuclear potentials between the α particle and daughter nuclei are obtained by using the double folding integral of the matter density distribution of the α particle and daughter nuclei with a density-dependent effective nucleon-nucleon interaction, in which the zero-range exchange term is supplemented. The calculated α decay half-lives are compared with those of the different models and experimental data. It is shown that the present calculation successfully provides the half-lives of the observed αdecays for some new superheavy elements and therefore gives reliable predictions for α decay of possibly synthesized superheavy elements in future experiments.

  19. Alpha decay energies and half-lives for possibly synthesized superheavy elements

    Institute of Scientific and Technical Information of China (English)

    ZHI Qi-Jun; REN Zhong-Zhou; ZHANG Xiao-Ping; ZHOU Xiao-Hong; GAN Zai-Guo; QIN Zhi; XU Hu-Shan

    2008-01-01

    We investigate the ground state properties of some superheavy nuclei, which may be synthesized in future experiments. Special emphases are placed on the alpha decay energies and half-lives. The alpha decay energies and half-lives from different theoretical models are compared and discussed comprehensively. Through these calculations and comparisons, the optimal superheavy elements to be synthesized in future experiments are proposed theoretically.

  20. Microscopic description of neutron emission rates in compound nuclei

    CERN Document Server

    Zhu, Yi

    2014-01-01

    The neutron emission rates in thermal excited nuclei are conventionally described by statistical models with a phenomenological level density parameter that depends on excitation energies, deformations and mass regions. In the microscopic view of hot nuclei, the neutron emission rates can be determined by the external neutron gas densities without any free parameters. Therefore the microscopic description of thermal neutron emissions is desirable that can impact several understandings such as survival probabilities of superheavy compound nuclei and neutron emissivity in reactors. To describe the neutron emission rates microscopically, the external thermal neutron gases are self-consistently obtained based on the Finite-Temperature Hartree-Fock-Bogoliubov (FT-HFB) approach. The results are compared with the statistical model to explore the connections between the FT-HFB approach and the statistical model. The Skyrme FT-HFB equation is solved by HFB-AX in deformed coordinate spaces. Based on the FT-HFB approach...

  1. Are analogues of hot subdwarf stars responsible for the UVX phenomenon in galaxy nuclei?

    CERN Document Server

    Dorman, B; Rood, R T; Ben Dorman

    1994-01-01

    We present the case that populations of sdB/sdOB/sdO-type stars may be a common constituent of galactic stellar populations, responsible for the UV upturn ("UVX") observed in the spectra of spiral bulges and normal galaxy nuclei. Extreme Horizontal Branch stars with $\\log g > 5$ and $\\log \\teff > 20,000K$ have emerged in the last few years as the most likely candidate for the origin of the UVX. The magnitude of this far-UV flux in some systems (e.g. NGC~1399, NGC~4649) indicates that galactic nuclear regions must contain larger numbers of these subdwarfs than does the solar neighbourhood. This paper summarizes the results of a quantitative study of the UV radiation from evolved stellar populations. We have computed a large grid of stellar models in advanced stages of evolution, as well as a set of isochrones for ages 2-20 Gyr, for a wide range in composition. We use these calculations to derive synthetic UV colour indices for stellar populations with hot components.

  2. Entrance channel effects in superheavy element production

    Science.gov (United States)

    Nasirov, Avazbek; Giardina, Giorgio; Mandaglio, Giuseppe; Muminov, Akhtam

    2016-12-01

    The difference between evaporation residue cross sections measured in the cold (X+208Pb, 209Bi) and hot (48Ca+actinides) fusion reactions can be related to the stage of compound nucleus (CN) formation and/or to the stage of its survival against fission. The cold fusion reactions are favorable in synthesis of the superheavy elements (SHE) with charge numbers Z fusion reactions due to small excitation energy and large fission barrier of the CN formed in these reactions. The strong decrease of the cross sections of the synthesis of the SHE Z = 113 in the cold fusion reactions in comparison with the ones in the hot fusion reactions is the result of the increase of hindrance to the CN formation in the cold fusion reactions. The origin of the intrinsic fusion barrier, B, causing the strong decrease of the probability PCN in the cold fusion is discussed.

  3. Superheavy dark matter

    CERN Document Server

    Chung, Daniel J.H.; Riotto, Antonio; Chung, Daniel J. H.; Kolb, Edward W.; Riotto, Antonio

    1999-01-01

    We show that, contrary to the standard lore, dark matter may be superheavy (many orders of magnitude larger than the weak scale). We show that massive particles may be produced naturally during the transition from the inflationary phase to either a matter-dominated or radiation-dominated phase as a result of the expansion of the background spacetime acting on vacuum quantum fluctuations of the dark matter field. We find that as long as there are stable particles whose mass is of the order of the inflaton mass (presumably around 10^13 GeV), they will be produced in sufficient abundance to give Omega_0=1 quite independently of any details of the non-gravitational interactions of the dark-matter field.

  4. Superheavy elements: existence, classification and experiment

    OpenAIRE

    Kostyghin, V. A.; Vaschenko, V. M.; Loza, Ye. A.

    2012-01-01

    This paper proposes spatial periodic table developed based on classic electron shell structure model. The periodic table determines location and chemical properties of superheavy elements. 14 new long-living superheavy elements found by Proton-21 laboratory and one long-living superheavy element found by A.Marinov were identified.

  5. Spontaneous fission properties of superheavy elements

    Energy Technology Data Exchange (ETDEWEB)

    Hessberger, F.P. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Helmholtz-Institut Mainz, Mainz (Germany)

    2017-04-15

    Spontaneous fission properties of transuranium isotopes are reviewed. Specific emphasis was laid on brief historical overviews of theoretical descriptions and experimental determination of basic properties as spontaneous fission half-lives, fission barriers, or total kinetic energy release in fission. Experimental spontaneous fission half-lives are compared with the results of recent theoretical predictions. Hindrance factors for spontaneous fission of odd-mass nuclei are discussed in context with the configuration (spin, parity) of the fissioning states and the change in energy of single particle levels at deformation. Kinetic energy release and mass distributions are discussed in the context of different fission modes, as symmetric and asymmetric or fission from elongated or compact shapes of the nascent fission fragments. An overview of recent fission barrier calculations of superheavy elements on the basis of macroscopic-microscopic models or self-consistent calculations is given, and the results are compared for selected examples. (orig.)

  6. Alpha Decay Preformation Factors for Even-Even 280-316116 Superheavy Isotopes

    Science.gov (United States)

    Alsaif, Norah A. M.; Radiman, Shahidan; Yahaya, Redzuwan; Ahmed, Saad M. Saleh

    2016-06-01

    The success of the cluster formation model (CFM) in deriving an energy-dependent formula for the preformation factors of heavy nuclei has motivated us to expand this approach to the superheavy isotopes (SHI). In this paper, the alpha-cluster formation (preformation factor) behavior inside the parent nuclei of SHI with atomic number Z = 116 and neutron numbers 164 ≤ N ≤ 200 is determined using the alpha preformation formula contained within the CFM. The cluster formation energy of the alpha particles and the total energy of the parent nuclei are calculated on the basis of the various binding energies. Our results clearly show that the CFM remains valid for superheavy nuclei (SHN). In addition, our calculations reveal that the alpha clustering mechanism and formation probability in 280-316116 even-even SHI are similar to those of even-even heavy nuclei in a general sense.

  7. Synthesis of superheavy elements at the Dubna gas-filled recoil separator

    Energy Technology Data Exchange (ETDEWEB)

    Voinov, A. A., E-mail: voinov@jinr.ru [Joint Institute for Nuclear Research (Russian Federation); Collaboration: JINR (Dubna), LLNL (Livermore), ORNL (Oak Ridge), University of Tennessee (Knoxville), Vanderbilt University (Nashville), Research Institute of Atomic Reactors (Dimitrovgrad) Collaboration

    2016-12-15

    A survey of experiments at the Dubna gas-filled recoil separator (Laboratory of Nuclear Reactions, JINR, Dubna) aimed at the detection and study of the “island of stability” of superheavy nuclei produced in complete fusion reactions of {sup 48}Ca ions and {sup 238}U–{sup 249}Cf target nuclei is given. The problems of synthesis of superheavy nuclei, methods for their identification, and investigation of their decay properties, including the results of recent experiments at other separators (SHIP, BGS, TASCA) and chemical setups, are discussed. The studied properties of the new nuclei, the isotopes of elements 112–118, as well as the properties of their decay products, indicate substantial growth of stability of the heaviest nuclei with increasing number of neutrons in the nucleus as the magic number of neutrons N = 184 is approached.

  8. Manifestation of the structure of heavy nuclei in their alpha decays

    Energy Technology Data Exchange (ETDEWEB)

    Adamian, G. G., E-mail: adamian@theor.jinr.ru; Antonenko, N. V.; Bezbakh, A. N.; Malov, L. A. [Joint Institute for Nuclear Research (Russian Federation)

    2016-11-15

    Low-lying one- and two-quasiparticle states of heavy nuclei are predicted. Alpha-decay chains, including those that proceed through isomeric states, are examined on the basis of the predicted properties of superheavy nuclei.

  9. On the Production of Superheavy Elements

    CERN Document Server

    Armbruster, P

    2003-01-01

    Since the discovery of Deformed Superheavy Nuclei (1983–85) a bridge connects the island of SHE to known isotopes of lighter elements. What we know experimentally and theoretically on the nuclear structure of SHE is reported in a first section. The making of the elements, with an analysis of production cross sections, and the macroscopic limitation to Z=112+ is presented in a second section. The break-down of fusion cross sections in the ‘Coulomb Falls’ within a range of about 10 elements is introduced as the universal limiting phenomenon. How the nuclear structure of the collision partners modifies the on-set of this limitation is presented in Section 3. Reactions induced by deformed nuclei are pushed by side collisions to higher excitation energies (4n- and 5n-channels), whereas reactions driven by the cluster-like, closed-shell nuclei, 208126Pb and 13882Ba, are kept at low excitation energies (1n- and 2n-channels). The on-set of production limitation for deformed collision partners is moved to smalle...

  10. Evaporation residue cross sections for the {sup 64}Ni + {sup 144,154}Sm reaction -- Energy dissipation in hot nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Back, B.B.; Blumenthal, D.J.; Davids, C.N. [and others

    1995-08-01

    The fission hindrance of hot nuclei was deduced recently from an enhanced emission of GDR {gamma} rays, neutrons and charged particles prior to scission of heavy nuclei. In the most recent experiments addressing this topic, namely new measurements of the pre-scission {gamma} rays and evaporation residues from the {sup 32}S + {sup 184}W reaction, a rather sharp transition from negligible to full one-body dissipation occurs over the excitation energy region E{sub exc} = 60-100 MeV. However, the cross section does not appear to level out or start to decline again at the upper end of the energy range as expected in this interpretation. It is therefore clearly desirable to extend the excitation energy range to look for such an effect in order to either corroborate or refute this interpretation.

  11. Searches for the superheavy hydrogen isotope H-7 in the absorption of stopped pi(-) mesons

    NARCIS (Netherlands)

    Gurov, Yu. B.; Aleshkin, D. V.; Lapushkin, S. V.; Laukhin, I. V.; Pechkurov, V. A.; Poroshin, N. O.; Sandukovsky, V. G.; Tel'kushev, M. V.; Chernyshev, B. A.

    2006-01-01

    Experimental searches for the superheavy hydrogen isotope H-7 were performed in reactions involving the absorption of stopped pi(-) mesons on Be-9 and B-11 nuclei. In the reaction Be-9(pi(-), pp)X, the missing-mass spectrum shows evidence for the formation of H-7 states, that of E-r = 16 +/- 1 MeV a

  12. Production mechanism of hot nuclei in violent collisions in the Fermi energy domain

    OpenAIRE

    Veselsky, M.

    2001-01-01

    A production mechanism of highly excited nuclei formed in violent collisions in the Fermi energy domain is investigated. The collision of two nuclei is decomposed into several stages which are treated separately. Simplified exciton concept is used for the description of pre-equilibrium emission. A modified spectator-participant scenario is used where motion along classical Coulomb trajectories is assumed. The participant and one of the spectator zones undergo incomplete fusion. Excitation ene...

  13. Evidence for primordial superheavy elements

    Energy Technology Data Exchange (ETDEWEB)

    Gentry, R.V.; Cahill, T.A.; Fletcher, N.R.; Kaufmann, H.C.; Medsker, L.R.; Nelson, J.W.; Flocchini, R.G.

    1976-07-05

    Microscopic crystalline monazite inclusions showing giant halo formation in biotite mica have been analyzed by the method of proton-induced x-ray emission. The observed x-ray energy spectra are best explained by the presence of a number of superheavy elements. (AIP)

  14. INDRA and hot nuclei: report and prospects, March 1999; INDRA et les noyaux chauds: bilan et perspectives, Mars 1999

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-07-01

    The main objective targeted by INDRA collaboration was obtaining a major advance in understanding the hot nuclear matter by means of nucleus-nucleus collisions through the study of multifragmentation. The idea was to create a 4{pi} multidetector more advanced then the earlier detectors: NAUTILUS (GANIL), 4{pi} ARRAY (MSU) and AMPHORA (SARA). At present, the INDRA collaboration gathers the laboratories of DAPNIA (CEA-Saclay), GANIL (Caen), IPN (Orsay), IPN (Lyon) and LPC (Caen). The international collaboration linked with the groups of Florence and Naples and with the CHIMERA collaboration in Italy, the LAVAL group from Canada, the group of Bucharest, Romania and the ALADIN group (GSI Darmstadt) from Germany, made the success of INDRA collaboration in gathering the physicists working in this field. The INDRA detector, made up of 336 modules of 2 or 3 detection steps, has a large spatial aperture (90%) and granularity which allows correlation studies. The minimization of the detection thresholds, coupled to the systematic utilization of charge coding, enabled detecting and identifying the charged products of energy range, never reached before, of 1 MeV protons up to 5 GeV uranium nuclei. The bombarding energy covers the range of 25 - 150 MeV/nucleon. The report reviews the production mechanisms and thermodynamics of hot nuclei and the multifragmentation reactions. Finally, the report presents the short term (1999-2001) and the medium term (2000-2005) prospects.

  15. Mean-field models and exotic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Bender, M.; Buervenich, T.; Maruhn, J.A.; Greiner, W. [Inst. fuer Theoretische Physik, Univ. Frankfurt (Germany); Rutz, K. [Inst. fuer Theoretische Physik, Univ. Frankfurt (Germany)]|[Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Reinhard, P.G. [Inst. fuer Theoretische Physik, Univ. Erlangen (Germany)

    1998-06-01

    We discuss two widely used nuclear mean-field models, the relativistic mean-field model and the (nonrelativistic) Skyrme-Hartree-Fock model, and their capability to describe exotic nuclei. Test cases are superheavy nuclei and neutron-rich Sn isotopes. New information in this regime helps to fix hitherto loosely determined aspects of the models. (orig.)

  16. Hot nuclei in reactions induced by heavy projectiles, protons and antiprotons

    Energy Technology Data Exchange (ETDEWEB)

    Galin, J.

    1995-12-31

    Light projectiles like protons and antiprotons with several GeV kinetic energy enable a very efficient heating of nuclei, similar to what is routinely achieved in nucleus-nucleus collisions. At the same time, the excitation of the collective modes in nuclei is minimized, making possible for the first time the study of the heat effects exclusively. The scarcity of multifragmentation in antiproton induced reactions on heavy targets seems to show that when such a phenomenon occurs in a nucleus-nucleus collisions it is most likely driven by initial compression and angular momentum rather than heat. (author). 41 refs.

  17. Study of dissipative dynamics in fission of hot nuclei using Langevin equation

    CERN Document Server

    Chaudhuri, G

    2004-01-01

    The fission of highly excited compound nuclei formed in heavy ion induced fusion reactions has emerged as a topic of considerable interest in the recent years. Dissipative dynamical models based on the Langevin equation were developed and were applied successfully for fission dynamics of highly excited heavy nuclei. However, Wall Friction(WF), the standard version of nuclear friction when incorporated in the Langevin dynamical model was not able to reproduce simultaneously experimental data for both prescission neutron multiplicity and fission probability. Consequently, an empirical reduction in the strength of the wall friction was found necessary to reproduce the experimental numbers by many workers. Interestingly, a modification of the wall friction was proposed recently where the reduction was achieved microscopically. This modified version is known as the chaos weighted wall friction(CWWF) which takes into account non-integrability of single particle motion. The work in my thesis aims at using this stron...

  18. Damping Mechanism of the Giant Dipole Resonance in Hot Nuclei with A=130

    Science.gov (United States)

    Wieland, O.; Bracco, A.; Camera, F.; Benzoni, G.; Blasi, N.; Crespi, F. C. L.; Leoni, S.; Million, B.; Barlini, S.; Kravchuk, V. L.; Gramegna, F.; Lanchais, A.; Maj, A.; Kmiecik, M.; Casini, G.; Chiari, M.; Nannini, A.; Bruno, M.; Geraci, E.

    2007-04-01

    The gamma decay of the Giant Dipole Resonance (GDR) in 132Ce nuclei has been measured using the reactions 64Ni (Elab= 300, 400, 500 MeV) + 68Zn and 16O (Elab= 130,250 MeV) + 116Sn. The analysis of the data shows clearly that the GDR width increases steadily with temperature at least up to 4 MeV of the temperature. The data can be well interpreted within the thermal shape fluctuation model.

  19. The Chemistry of Superheavy Elements

    CERN Document Server

    Schädel, M

    2003-01-01

    The chemistry of transactinide or superheavy elements has reached element 108. Preparations are under way to leap to element 112 and beyond. The current status of this atom-at-a-time chemical research and its future perspectives are reviewed from an experimental point of view together with some of the interesting results from n -rich nuclides near and at the N=162 neutron shell. Experimental techniques and important results enlightening typical chemical properties of elements 104 through 108 are presented in an exemplary way. From the results of these experiments it is justified to place these elements in the Periodic Table of the Elements in to groups 4 through 8, respectively. However, mainly due to the influence of relativistic effects, it is no longer possible to deduce detailed chemical properties of these superheavy elements simply from this position.

  20. The Skyrme-TQRPA calculations of electron capture on hot nuclei in pre-supernova environment

    CERN Document Server

    Dzhioev, Alan A; Stoyanov, Ch

    2016-01-01

    We combine the thermal QRPA approach with the Skyrme energy density functional theory (Skyrme-TQRPA) for modelling the process of electron capture on nuclei in supernova environment. For a sample nucleus, $^{56}$Fe, the Skyrme-TQRPA approach is applied to analyze thermal effects on the strength function of GT$_+$ transitions which dominate electron capture at $E_e\\le 30$~MeV. Several Skyrme interactions are used in order to verify the sensitivity of the obtained results to the Skyrme force parameters. Finite-temperature cross sections are calculated and the results are compared with those of the other model calculations.

  1. The Skyrme-TQRPA calculations of electron capture on hot nuclei in pre-supernova environment

    Energy Technology Data Exchange (ETDEWEB)

    Dzhioev, Alan A., E-mail: dzhioev@theor.jinr.ru; Vdovin, A. I., E-mail: vdovin@theor.jinr.ru [JINR, Bogoliubov Laboratory of Theoretical Physics (Russian Federation); Stoyanov, Ch., E-mail: stoyanov@inrne.bas.bg [Bulgarian Academy of Sciences, Institute for Nuclear Research and Nuclear Energy (Bulgaria)

    2016-11-15

    We combine the thermal QRPA approach with the Skyrme energy density functional theory (Skyrme–TQRPA) for modelling the process of electron capture on nuclei in supernova environment. For a sample nucleus, {sup 56}Fe, the Skyrme–TQRPA approach is applied to analyze thermal effects on the strength function of GT{sub +} transitions which dominate electron capture at E{sub e} ≤ 30 MeV. Several Skyrme interactions are used in order to verify the sensitivity of the obtained results to the Skyrme force parameters. Finite-temperature cross sections are calculated and the results are comparedwith those of the other model calculations.

  2. The Skyrme-TQRPA calculations of electron capture on hot nuclei in pre-supernova environment

    Science.gov (United States)

    Dzhioev, Alan A.; Vdovin, A. I.; Stoyanov, Ch.

    2016-11-01

    We combine the thermal QRPA approach with the Skyrme energy density functional theory (Skyrme-TQRPA) for modelling the process of electron capture on nuclei in supernova environment. For a sample nucleus, 56Fe, the Skyrme-TQRPA approach is applied to analyze thermal effects on the strength function of GT+ transitions which dominate electron capture at E e ≤ 30 MeV. Several Skyrme interactions are used in order to verify the sensitivity of the obtained results to the Skyrme force parameters. Finite-temperature cross sections are calculated and the results are comparedwith those of the other model calculations.

  3. Stability against $\\alpha$ decay of some recently observed superheavy elements

    CERN Document Server

    Chowdhury, Partha Roy; Bhattacharyya, Abhijit

    2011-01-01

    The probability of $\\alpha$ particle emission for some recently observed superheavy nuclei (SHN) are investigated. The $\\alpha$-decay half lives of SHN are calculated in a quantum tunneling model with density dependent M3Y (DDM3Y) effective nuclear interaction using theoretical and measured $Q_\\alpha$ values. We determine the density distribution of $\\alpha$ and daughter nuclei from the relativistic mean field theory (RMF) using FSUGold force, NL3 and TM1 parameter sets. The double folded nuclear potential is numerically calculated in a more microscopic manner using these density distributions. The estimated values of $\\alpha$-decay half-lives are in good agreement with the recent data. We compare our results with recently detected $\\alpha$-decay chains from new element with atomic number Z=117 reported by JINR, Dubna. Finally, we determine the half-lives of superheavy elements with Z=108-120 and neutron number N=152-190 to explore the long-standing predictions on the existence of an "island of stability" due...

  4. Hot Bubbles from Active Galactic Nuclei as a Heat Source in Cooling Flow Clusters

    CERN Document Server

    Brüggen, M; Brueggen, Marcus; Kaiser, Christian R.

    2002-01-01

    The hot plasma permeating clusters of galaxies often shows a central peak in the X-ray surface brightness that is coincident with a drop in entropy. This is taken as evidence for a cooling flow where the radiative cooling in the central regions of a cluster causes a slow subsonic inflow. Searches in all wavebands have revealed significantly less cool gas than predicted indicating that the mass deposition rate of cooling flows is much lower than expected. However, most cooling flow clusters host an Active Galactic Nucleus (AGN) at their centres. AGN can inflate large bubbles of hot plasma that subsequently rise through the cluster atmosphere, thus stirring this gas. Here we report on the results from highly resolved hydrodynamic simulations which for the first time show that buoyant bubbles increase the cooling time in the inner cluster regions and thereby significantly reduce the deposition of cold gas. This work demonstrates that the action of AGN in the centres of cooling flow clusters can explain the obser...

  5. Thermal Multifragmentation of Hot Nuclei and Liquid-Fog Phase Transition

    CERN Document Server

    Karnaukhov, V A; Duginova, E V; Petrov, L A; Rodionov, V K; Oeschler, H; Budzanowski, A; Karcz, W; Janicki, M; Bochkarev, O V; Kuzmin, E A; Chulkov, L V; Norbeck, E; Botvina, A S

    2002-01-01

    Multiple emission of intermediate-mass fragments in the collisions of protons (up to 8.1 GeV), ^{4}He (4 and 14.6 GeV) and ^{12}C (22.4 GeV) on Au has been studied with the 4\\pi-setup FASA. In all cases thermal multifragmentation of the hot and diluted target spectator takes place. The fragment multiplicity and charge distributions are well described by the combined model including the modified intranuclear cascade followed by the statistical multibody decay of the hot system. IMF-IMF correlation study supports this picture giving very short time scale of the process (\\tau\\le 70 fm/c). This decay process can be interpreted as the first order nuclear liquid-fog phase transition inside the spinodal region. The evolution of the mechanism of thermal multifragmentation with increasing projectile mass was investigated. The onset of the radial collective flow was observed for heavier projectiles. The analysis reveals the information on the fragment space distribution ins! ide the break-up volume: heavier IMF are for...

  6. Entrance channel effects in superheavy element production

    Directory of Open Access Journals (Sweden)

    Nasirov Avazbek

    2016-01-01

    Full Text Available The difference between evaporation residue cross sections measured in the cold (X+208Pb, 209Bi and hot (48Ca+actinides fusion reactions can be related to the stage of compound nucleus (CN formation and/or to the stage of its survival against fission. The cold fusion reactions are favorable in synthesis of the superheavy elements (SHE with charge numbers Z < 112 in comparison with the hot fusion reactions due to small excitation energy and large fission barrier of the CN formed in these reactions. The strong decrease of the cross sections of the synthesis of the SHE Z = 113 in the cold fusion reactions in comparison with the ones in the hot fusion reactions is the result of the increase of hindrance to the CN formation in the cold fusion reactions. The origin of the intrinsic fusion barrier, B*fus, causing the strong decrease of the probability PCN in the cold fusion is discussed.

  7. Tracking the phase-transition energy in disassembly of hot nuclei

    CERN Document Server

    Das, C B; Beaulieu, L; Lefort, T; Kwiatkowski, K K; Viola, V E; Yennello, S J; Pienkowski, L; Korteling, R G; Breuer, H

    2002-01-01

    In efforts to determine phase transitions in the disintegration of highly excited heavy nuclei, a popular practice is to parametrise the yields of isotopes as a function of temperature in the form $Y(z)=z^{-\\tau}f(z^{\\sigma}(T-T_0))$, where $Y(z)$'s are the measured yields and $\\tau, \\sigma$ and $T_0$ are fitted to the yields. Here $T_0$ would be interpreted as the phase transition temperature. For finite systems such as those obtained in nuclear collisions, this parametrisation is only approximate and hence allows for extraction of $T_0$ in more than one way. In this work we look in detail at how values of $T_0$ differ, depending on methods of extraction. It should be mentioned that for finite systems, this approximate parametrisation works not only at the critical point, but also for first order phase transitions (at least in some models). Thus the approximate fit is no guarantee that one is seeing a critical phenomenon. A different but more conventional search for the nuclear phase transition would look fo...

  8. A pilgrimage through superheavy valley

    Indian Academy of Sciences (India)

    M Bhuyan; S K Patra

    2014-05-01

    We searched for the shell closure proton and neutron numbers in the superheavy region beyond = 82 and = 126 within the framework of non-relativistic Skryme–Hartree–Fock (SHF) with FITZ, SIII, SkMP and SLy4 interactions. We have calculated the average proton pairing gap $_p$, average neutron pairing gap $_n$, two-nucleon separation energy $S_{2q}$ and shell correction energy shell for the isotopic chain of = 112–126. Based on these observables, = 120 with = 182 is suggested to be the magic numbers in the present approach.

  9. Synthesis and properties of superheavy elements

    CERN Document Server

    Hofmann, S

    2003-01-01

    The nuclear shell model predicts that the next doubly magic shell-closure beyond sup 2 sup 0 sup 8 Pb is at a proton number Z = 114, 120, or 126 and at a neutron number N = 172 or 184. The outstanding of experimental investigations is the exploration of this region of spherical 'SuperHeavy Elements' (SHEs). Experimental methods are described which allowed for the identification of elements 107 to 112 in studies of cold fusion reactions based on lead and bismuth targets. Also presented are data which were obtained on the synthesis of elements 112, 114, and 116 in investigation of hot fusion reactions using actinide targets. The decay data reveal that for the heaviest elements, the dominant decay mode is alpha emission, not fission. Decay properties as well as reaction cross- sections are compared with the results of theoretical studies. Finally, plans are presented for the further development of the experimental set-up and the application of new techniques. At a higher sensitivity, the exploration of the regio...

  10. Dynamics of light, intermediate, heavy and superheavy nuclear systems formed in heavy-ion collisions

    Indian Academy of Sciences (India)

    Manoj K Sharma; Gurvinder Kaur

    2014-05-01

    The dynamical description of light, intermediate, heavy and superheavy nuclei formed in heavy-ion collisions is worked out using the dynamical cluster decay model (DCM), with reference to various effects such as deformation and orientation, temperature, angular momentum etc. Based on the quantum mechanical fragmentation theory (QMFT), DCM has been applied to understand the decay mechanism of a large number of nuclei formed in low-energy heavy-ion reactions. Various features related to the dynamics of competing decay modes of nuclear systems are explored by addressing the experimental data of a number of reactions in light, intermediate, heavy and superheavy mass regions. The DCM, being a non-statistical description for the decay of a compound nucleus, treats light particles (LPs) or equivalently evaporation residues (ERs), intermediate mass fragments (IMFs) and fission fragments on equal footing and hence, provides an alternative to the available statistical model approaches to address fusion–fission and related phenomena.

  11. Hot and dense matter in compact stars - from nuclei to quarks

    Energy Technology Data Exchange (ETDEWEB)

    Hempel, Matthias

    2010-10-19

    This dissertation deals with the equation of state of hot and dense matter in compact stars, with special focus on first order phase transitions. A general classification of first order phase transitions is given and the properties of mixed phases are discussed. Aspects of nucleation and the role of local constraints are investigated. The derived theoretical concepts are applied to matter in neutron stars and supernovae, in the hadron-quark and the liquid-gas phase transition. For the detailed description of the liquid-gas phase transition a new nuclear statistical equilibrium model is developed. It is based on a thermodynamic consistent implementation of relativistic mean-field interactions and excluded volume effects. With this model different equation of state tables are calculated and the composition and thermodynamic properties of supernova matter are analyzed. As a first application numerical simulations of core-collapse supernovae are presented. For the hadron-quark phase transition two possible scenarios are studied in more detail. First the appearance of a new mixed phase in a proto neutron star and the implications on its evolution. In the second scenario the consequences of the hadron-quark transition in corecollapse supernovae are investigated. Simulations show that the appearance of quark matter has clear observable signatures and can even lead to the generation of an explosion. (orig.)

  12. Z=110-111 elements and the stability of heavy and superheavy elements

    CERN Document Server

    Wu Cheng Li; Feng, D H

    1995-01-01

    The recent discovery of isotopes with Z=110--111 suggests evidence for (1) a monopole--monopole interaction that does not appear explicitly in Nilsson--Strutinsky mass systematics, and (2) a competition between SU(2) and SU(3) dynamical symmetries that has been predicted for this region. Our calculations suggest that these new isotopes are near spherical, and may represent a true island of superheavy nuclei, but shifted downward in neutron number by these new physical effects.

  13. Chemical experiments with superheavy elements.

    Science.gov (United States)

    Türler, Andreas

    2010-01-01

    Unnoticed by many chemists, the Periodic Table of the Elements has been extended significantly in the last couple of years and the 7th period has very recently been completed with eka-Rn (element 118) currently being the heaviest element whose synthesis has been reported. These 'superheavy' elements (also called transactinides with atomic number > or = 104 (Rf)) have been artificially synthesized in fusion reactions at accelerators in minute quantities of a few single atoms. In addition, all isotopes of the transactinide elements are radioactive and decay with rather short half-lives. Nevertheless, it has been possible in some cases to investigate experimentally chemical properties of transactinide elements and even synthesize simple compounds. The experimental investigation of superheavy elements is especially intriguing, since theoretical calculations predict significant deviations from periodic trends due to the influence of strong relativistic effects. In this contribution first experiments with hassium (Hs, atomic number 108), copernicium (Cn, atomic number 112) and element 114 (eka-Pb) are reviewed.

  14. Giant dipole resonance built on hot rotating nuclei produced during evaporation of light particles from the 88Mo compound nucleus

    Science.gov (United States)

    Ciemała, M.; Kmiecik, M.; Maj, A.; Mazurek, K.; Bracco, A.; Kravchuk, V. L.; Casini, G.; Barlini, S.; Baiocco, G.; Bardelli, L.; Bednarczyk, P.; Benzoni, G.; Bini, M.; Blasi, N.; Brambilla, S.; Bruno, M.; Camera, F.; Carboni, S.; Cinausero, M.; Chbihi, A.; Chiari, M.; Corsi, A.; Crespi, F. C. L.; D'Agostino, M.; Degerlier, M.; Fornal, B.; Giaz, A.; Gramegna, F.; Krzysiek, M.; Leoni, S.; Marchi, T.; Matejska-Minda, M.; Mazumdar, I.; Meczyński, W.; Million, B.; Montanari, D.; Morelli, L.; Myalski, S.; Nannini, A.; Nicolini, R.; Pasquali, G.; Piantelli, S.; Prete, G.; Roberts, O. J.; Schmitt, Ch.; Styczeń, J.; Szpak, B.; Valdré, S.; Wasilewska, B.; Wieland, O.; Wieleczko, J. P.; Ziebliński, M.; Dudek, J.; Dinh Dang, N.

    2015-05-01

    High-energy giant dipole resonance (GDR) γ rays were measured following the decay of the hot, rotating compound nucleus of 88Mo, produced at excitation energies of 124 and 261 MeV. The reaction 48Ti + 40Ca at 300 and 600 MeV bombarding energies has been used. The data were analyzed using the statistical model Monte Carlo code gemini++. It allowed extracting the giant dipole resonance parameters by fitting the high-energy γ -ray spectra. The extracted GDR widths were compared with the available data at lower excitation energy and with theoretical predictions based on (i) The Lublin-Strasbourg drop macroscopic model, supplemented with thermal shape fluctuations analysis, and (ii) The phonon damping model. The theoretical predictions were convoluted with the population matrices of evaporated nuclei from the statistical model gemini++. Also a comparison with the results of a phenomenological expression based on the existing systematics, mainly for lower temperature data, is presented and discussed. A possible onset of a saturation of the GDR width was observed around T =3 MeV.

  15. Determination of the compound nucleus survival probability Psurv for various "hot" fusion reactions based on the dynamical cluster-decay model

    Science.gov (United States)

    Chopra, Sahila; Kaur, Arshdeep; Gupta, Raj K.

    2015-03-01

    After a successful attempt to define and determine recently the compound nucleus (CN) fusion/ formation probability PCN within the dynamical cluster-decay model (DCM), we introduce and estimate here for the first time the survival probability Psurv of CN against fission, again within the DCM. Calculated as the dynamical fragmentation process, Psurv is defined as the ratio of the evaporation residue (ER) cross section σER and the sum of σER and fusion-fission (ff) cross section σff, the CN formation cross section σCN, where each contributing fragmentation cross section is determined in terms of its formation and barrier penetration probabilities P0 and P . In DCM, the deformations up to hexadecapole and "compact" orientations for both in-plane (coplanar) and out-of-plane (noncoplanar) configurations are allowed. Some 16 "hot" fusion reactions, forming a CN of mass number ACN˜100 to superheavy nuclei, are analyzed for various different nuclear interaction potentials, and the variation of Psurv on CN excitation energy E*, fissility parameter χ , CN mass ACN, and Coulomb parameter Z1Z2 is investigated. Interesting results are that three groups, namely, weakly fissioning, radioactive, and strongly fissioning superheavy nuclei, are identified with Psurv, respectively, ˜1 ,˜10-6 , and ˜10-10 . For the weakly fissioning group (100 PCN belongs to the strongly fissioning superheavy group, Psurv belongs to weakly fissioning nuclei; for Pt* isotopes, the inverse of all the compound systems studied, both PCN and Psurv decrease with the increase of E*; for 213 ,215 ,217Fr* nuclei, though fissility χ is nearly the same, Psurv for 213 ,217Fr* is of the same order as for weakly fissioning nuclei, but that for 215Fr* is of the order of radioactive nuclei. Apparently, further calculations are called for.

  16. Experimental Probe to the Isospin-Dependent Properties of Hot Nuclei in Reactions 40Ar+112,124 Sn at 30 MeV/u

    Institute of Scientific and Technical Information of China (English)

    肖志刚; 靳根明; 吴和宇; 魏志勇; 王宏伟; 段利敏; 柳永英; 李祖玉; 张保国; 诸永泰; 王素芳; 卢朝晖; 朱海东; 胡荣江

    2001-01-01

    Protons are emitted in a greater quantity in a neutron-deficient system 40Ar+112Sn while triton emissions are greater in a neutron-rich system 40Ar+124Sn at an incident energy of 30 MeV/u. Similar to neutrons, proton emission provides a dominant contribution to neutralize the system N/Z in the decay process of the hot nuclei.The emission of hydrogen isotopes with high energies is much enhanced in the 112Sn system. The original temperature of the hot nuclei in the 40Ar+112Sn reaction is 5.8+0.3 MeV, about 0.7 MeV higher than 5.1+0.3MeV as in the 40Ar+124Sn reaction.

  17. Superheavy fragments produced in the asymmetric strongly damped collision

    Institute of Scientific and Technical Information of China (English)

    TIAN Jun-Long; WU Xi-Zhen; LI Zhu-Xia; ZHAO Kai

    2008-01-01

    The strongly damped collisions of very heavy nuclei 232Th+250Cf at the energy range of 680-1880 MeV have been studied within the improved quantum molecular dynamics model. The production probability of primary superheavy fragments with Z ≥ 114 (SHFs) for the asymmetric reaction 232Th+250Cf is higher than that for the symmetric reaction 244Pu+244Pu and 238U+238U. The calculated results show that the mass and charge distributions of primary fragments, the excitation energy distribution of SHFs depend on the incident energies strongly. Two stages of the decay process of composite systems are distinguished by very different decay slopes, which imply different decay mechanisms of the composite system. The first stage is for the decay of giant composite systems and the second one corresponds to the decay of fragments of giant composite systems including SHFs through emitting neutron, proton or other charged particles, and also through fission or fragmentation. The slow reduction of SHFs in the second stage seems to be helpful for the survival of primary superheavy fragments.

  18. Madelung rule violation statistics and superheavy elements electron shell prediction

    CERN Document Server

    Loza, E

    2012-01-01

    The paper presents tetrahedron periodic table to conveniently include superheavy elements. Madelung rule violation statistics is discussed and a model for Madelung rule violation probability calculation is proposed. On its basis superheavy elements probable electron shell structure is determined.

  19. Nuclear spectroscopy with Geant4. The superheavy challenge

    Science.gov (United States)

    Sarmiento, Luis G.

    2016-12-01

    The simulation toolkit Geant4 was originally developed at CERN for high-energy physics. Over the years it has been established as a swiss army knife not only in particle physics but it has seen an accelerated expansion towards nuclear physics and more recently to medical imaging and γ- and ion- therapy to mention but a handful of new applications. The validity of Geant4 is vast and large across many particles, ions, materials, and physical processes with typically various different models to choose from. Unfortunately, atomic nuclei with atomic number Z > 100 are not properly supported. This is likely due to the rather novelty of the field, its comparably small user base, and scarce evaluated experimental data. To circumvent this situation different workarounds have been used over the years. In this work the simulation toolkit Geant4 will be introduced with its different components and the effort to bring the software to the heavy and superheavy region will be described.

  20. Dissipative dynamics of the synthesis of superheavy elements

    Energy Technology Data Exchange (ETDEWEB)

    Wada, Takahiro; Aritomo, Y.; Tokuda, T.; Okazaki, K.; Ohta, M. [Konan Univ., Kobe (Japan). Dept. of Physics; Abe, Y.

    1997-07-01

    Fusion-fission process in heavy systems are analyzed by Smoluchowski equation taking into account the temperature dependent shell correction energy. The evaporation residue cross sections of superheavy elements have been shown to have an optimum value at a certain temperature, due to the balance between the diffusibility for fusion at high temperature and the restoration of the shell correction energy against fission at low temperature. The isotope dependence of the evaporation residue cross section is found to be very strong. Neutron rich compound system with small neutron separation energy is favorable for larger cross section because of the quick restoration of the shell correction energy. The Z-dependence is discussed for the formation of the compound nuclei with Z=102 to Z=114. (author)

  1. International Symposium on Exotic Nuclei

    CERN Document Server

    Sobolev, Yu G; EXON-2014

    2015-01-01

    The production and the properties of nuclei in extreme conditions, such as high isospin, temperature, angular momenta, large deformations etc., have become the subject of detailed investigations in all scientific centers. The main topics discussed at the Symposium were: Synthesis and Properties of Exotic Nuclei; Superheavy Elements; Rare Processes, Nuclear Reactions, Fission and Decays; Experimental Facilities and Scientific Projects. This book provides a comprehensive overview of the newest results of the investigations in the main scientific centers such as GSI (Darmstadt, Germany), GANIL (Caen, France), RIKEN (Wako-shi, Japan), MSU (Michigan, USA), and JINR (Dubna, Russia).

  2. Chemistry of the superheavy elements.

    Science.gov (United States)

    Schädel, Matthias

    2015-03-13

    The quest for superheavy elements (SHEs) is driven by the desire to find and explore one of the extreme limits of existence of matter. These elements exist solely due to their nuclear shell stabilization. All 15 presently 'known' SHEs (11 are officially 'discovered' and named) up to element 118 are short-lived and are man-made atom-at-a-time in heavy ion induced nuclear reactions. They are identical to the transactinide elements located in the seventh period of the periodic table beginning with rutherfordium (element 104), dubnium (element 105) and seaborgium (element 106) in groups 4, 5 and 6, respectively. Their chemical properties are often surprising and unexpected from simple extrapolations. After hassium (element 108), chemistry has now reached copernicium (element 112) and flerovium (element 114). For the later ones, the focus is on questions of their metallic or possibly noble gas-like character originating from interplay of most pronounced relativistic effects and electron-shell effects. SHEs provide unique opportunities to get insights into the influence of strong relativistic effects on the atomic electrons and to probe 'relativistically' influenced chemical properties and the architecture of the periodic table at its farthest reach. In addition, they establish a test bench to challenge the validity and predictive power of modern fully relativistic quantum chemical models.

  3. A way for synthesis of superheavy elements

    Energy Technology Data Exchange (ETDEWEB)

    Ohta, M.; Aritomo, Y.; Wada, T. [Konan Univ., Kobe (Japan). Dept. of Physics; Abe, Y.

    1997-05-01

    Fusion-fission process in heavy systems are analyzed by Smoluchowski equation taking into account the temperature dependent shell correction energy. The evaporation residue cross sections of superheavy elements have been shown to have an optimum value at a certain temperature, due to the balance between the diffusibility for fusion at high temperature and the restoration of the shell correction energy against fission at low temperature. The essential element which realize an significant yield for the (HI, 4-5n) reaction in superheavy mass region is found to be the characteristic time for cooling by neutron evaporation. (author)

  4. Alpha-Decay Half-Lives of Superheavy Nuclei

    Science.gov (United States)

    Budaca, A. I.; Silişteanu, I.; Silişteanu, A. O.; Anghel, C. I.

    2010-11-01

    Half-lives given by self-consistent models for the α-clustering and resonance scattering are calculated and compared with data and empirical estimates. The major influence of the pairing, deformed shell closures and screening corrections is evidenced in the systematics of half-lives and provides a convenient basis for the interpretation of observed trends of the data and for prediction of new results. The very small widths of α-resonances observed experimentally in fusion-evaporation reactions, are interpreted as resonance levels of radioactive products, and such a correlation contributes directly to the study of the nuclear structure on the basis of decay data.

  5. Formation of Superheavy Nuclei in Massive Fusion Reactions

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yu-min

    2009-01-01

    We recently performed a series of improvement on evaluation of eigenvalues without complicated iterations.In this work we first discuss evaluation of the lowest eigenvalue for given systems,by which one conveniently obtains the value of the lowest eigenvalue based on the dimension and width of given matrix.We also discuss a strong correlation between eigenvalues and diagonal matrix elements for large matrices,by which one is able to predict eigenvalues approximately without iterations.

  6. A novel approach to the island of stability of super-heavy elements search

    Directory of Open Access Journals (Sweden)

    Wieloch A.

    2016-01-01

    Full Text Available It is expected that the cross section for super-heavy nuclei production of Z > 118 is dropping into the region of tens of femto barns. This creates a serious limitation for the complete fusion technique that is used so far. Moreover, the available combinations of the neutron to proton ratio of stable projectiles and targets are quite limited and it can be difficult to reach the island of stability of super heavy elements using complete fusion reactions with stable projectiles. In this context, a new experimental investigation of mechanisms other than complete fusion of heavy nuclei and a novel experimental technique are invented for our search of super- and hyper-nuclei. This contribution is focused on that technique.

  7. Elements Discrimination in the Study of Super-Heavy Elements using an Ionization Chamber

    CERN Document Server

    Wieloch, A; Péter, J; Lojek, K; Alamanos, N; Amar, N; Anne, R; Angélique, J C; Auger, G; Dayras, R; Drouart, A; Fontbonne, J M; Gillibert, A; Grévy, S; Hanappe, F; Hannachi, F; Hue, R; Khouaja, A; Legou, T; López-Martens, A; Liénard, E; Manduci, L; De Oliveira-Santos, F; Politi, G; Saint-Laurent, M G; Stodel, C; Stuttgé, L; Tillier, J; De Tourreil, R; Villari, A C C; Wieleczko, J P

    2004-01-01

    Dedicated ionization chamber was built and installed to measure the energy loss of very heavy nuclei at 2.7 MeV/u produced in fusion reactions in inverse kinematics (beam of 208Pb). After going through the ionization chamber, products of reactions on 12C, 18O targets are implanted in a Si detector. Their identification through their alpha decay chain is ambiguous when their half-life is short. After calibration with Pb and Th nuclei, the ionization chamber signal allowed us to resolve these ambiguities. In the search for rare super-heavy nuclei produced in fusion reactions in inverse or symmetric kinematics, such a chamber will provide direct information on the nuclear charge of each implanted nucleus.

  8. A cruise in the archipelagos of superheavy elements, heavy-cluster emitters and nuclear molecules

    CERN Document Server

    Greiner, W

    2002-01-01

    I review some of the most important achievements in the theoretical investigations that we carried out in the last three decades at Frankfurt on the extension of the periodic system and heavy-ion emission. After discussing the problem of cold fusion and formation of Superheavy Elements (SHE) I will consider the reverse process, i.e. the spontaneous cold fragmentation of heavy nuclei into different channels like cluster radioactivity and cold fission. I will speculate on the properties of the putative quasi-molecules arising in the recent discovery of the triple fission of sup 2 sup 5 sup 2 Cf. (author)

  9. Status of the low-energy super-heavy element facility at RIKEN

    Energy Technology Data Exchange (ETDEWEB)

    Schury, P., E-mail: schury@riken.jp [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Wada, M.; Ito, Y. [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Arai, F. [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Institute of Physics, University of Tsukuba, Tsukuba City, Ibaraki (Japan); Kaji, D. [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Kimura, S. [Institute of Physics, University of Tsukuba, Tsukuba City, Ibaraki (Japan); Morimoto, K.; Haba, H. [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Jeong, S. [Institute of Particle and Nuclear Studies (IPNS), High Energy Accelerator Research Organization (KEK), Ibaraki 305-0801 (Japan); Koura, H. [Advanced Science Research Center, Japan Atomic Energy Agency, Ibaraki 319-1195 (Japan); Miyatake, H. [Institute of Particle and Nuclear Studies (IPNS), High Energy Accelerator Research Organization (KEK), Ibaraki 305-0801 (Japan); Morita, K.; Reponen, M. [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Ozawa, A. [Institute of Physics, University of Tsukuba, Tsukuba City, Ibaraki (Japan); Sonoda, T.; Takamine, A. [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Wollnik, H. [Dept. Chemistry and BioChemistry, New Mexico State University, Las Cruces, NM (United States)

    2016-06-01

    In order to investigate nuclei produced via fusion–evaporation reactions, especially super-heavy elements (SHE), we have begun construction of a facility for conversion of fusion–evaporation residues (EVR) to low-energy beams. At the base of this facility is a small cryogenic gas cell utilizing a traveling wave RF-carpet, located directly following the gas-filled recoil ion separator GARIS-II, which will thermalize EVRs to convert them into ion beams amenable to ion trapping. We present here the results of initial studies of this small gas cell.

  10. Analysis of spatial autocorrelation patterns of heavy and super-heavy rainfall in Iran

    Science.gov (United States)

    Rousta, Iman; Doostkamian, Mehdi; Haghighi, Esmaeil; Ghafarian Malamiri, Hamid Reza; Yarahmadi, Parvane

    2017-09-01

    Rainfall is a highly variable climatic element, and rainfall-related changes occur in spatial and temporal dimensions within a regional climate. The purpose of this study is to investigate the spatial autocorrelation changes of Iran's heavy and super-heavy rainfall over the past 40 years. For this purpose, the daily rainfall data of 664 meteorological stations between 1971 and 2011 are used. To analyze the changes in rainfall within a decade, geostatistical techniques like spatial autocorrelation analysis of hot spots, based on the Getis-Ord G i statistic, are employed. Furthermore, programming features in MATLAB, Surfer, and GIS are used. The results indicate that the Caspian coast, the northwest and west of the western foothills of the Zagros Mountains of Iran, the inner regions of Iran, and southern parts of Southeast and Northeast Iran, have the highest likelihood of heavy and super-heavy rainfall. The spatial pattern of heavy rainfall shows that, despite its oscillation in different periods, the maximum positive spatial autocorrelation pattern of heavy rainfall includes areas of the west, northwest and west coast of the Caspian Sea. On the other hand, a negative spatial autocorrelation pattern of heavy rainfall is observed in central Iran and parts of the east, particularly in Zabul. Finally, it is found that patterns of super-heavy rainfall are similar to those of heavy rainfall.

  11. Tensor Effect on Bubble Nuclei

    Institute of Scientific and Technical Information of China (English)

    WANG Yan-Zhao; GU Jian-Zhong; ZHANG Xi-Zhen; DONG Jian-Min

    2011-01-01

    In the framework of the Hartree-Fock-Bogoliubov (HFB) approach with Skyrme interactions SLy5+T, SLy5+Tw and several sets of TIJ parametrizations, I.e. The Skyrme interaction parametrizations including the tensor terms, the proton density distribution in 34Si and 46Ar nuclei is calculated with and without the tensor force. It is shown that the bubble effect in 34Si does not depend a great deal on the Skyrme parametrization and the proton density distribution in 34Si is hardly influenced by the tensor force. As to 46Ar, the SLy5+Tw parametrization favors the formation of the bubble structure due to the inversion between the 2s1/2 and 1d3/2 orbits (2s1/2-ld3/2 inversion). The inversion mechanism induced by the SLy5+Tw interaction is analyzed based on the proton single-particle spectra obtained from the SLy5 and SLy5+Tw interactions as well as the wave functions of the 2s1/2 and 1d3/2 states.%In the framework of the Hartree-Fock-Bogoliubov (HFB) approach with Skyrme interactions SLy5+ T,SLy5+ Tω and several sets of TIJ parametrizations,i.e.the Skyrme interaction pararmetrizations including the tensor terms,the proton density distribution in 34Si and 46 Ar nuclei is calculated with and without the tensor force.It is shown that the bubble effect in 34Si does not depend a great deal on the Skyrme parametrization and the proton density distribution in 34Si is hardly influenced by the tensor force.As to 46Ar,the SLy5+ Tω parametrization favors the formation of the bubble structure due to the inversion between the 2s1/2 and 1d3/2 orbits (2s1/2-1d3/2 inversion).The inversion mechanism induced by the SLy5+ Tω interaction is analyzed based on the proton single-particle spectra obtained from the SLy5 and SLy5+ Tω interactions as well as the wave functions of the 2s1/2 and 1d3/2 states.The study of exotic nuclear structures has been a hot topic in nuclear physics.[1-4] Exotic nuclei are unstabile,superheavy nuclei,halo nuclei and so forth,whose structures are quite different

  12. Electric dipole moments of superheavy elements

    CERN Document Server

    Radžiūtė, Laima; Jönsson, Per; Bieroń, Jacek

    2015-01-01

    The multiconfiguration Dirac-Hartree-Fock (MCDHF) method was employed to calculate atomic electric dipole moments (EDM) of the superheavy element copernicium (Cn, $Z=112$). The EDM enhancement factors of Cn, here calculated for the first time, are about one order of magnitude larger than those of Hg. The exponential dependence of enhancement factors on atomic number $Z$ along group 12 of the periodic table was derived from the EDMs of the entire homolog series, $^{69}_{30}$Zn, $^{111}_{\\phantom{1}48}$Cd, $^{199}_{\\phantom{1}80}$Hg, $^{285}_{112}$Cn, and $^{482}_{162}$Uhb. These results show that superheavy elements with sufficiently large half-lives are good candidates for EDM searches.

  13. Superheavy Elements Challenge Experimental and Theoretical Chemistry

    CERN Document Server

    Zvára, I

    2003-01-01

    When reflecting on the story of superheavy elements, the an experimenter, acknowledges the role, which the predictions of nuclear and chemical theories have played in ongoing studies. Today, the problems of major interest for experimental chemistry are the studies of elements 112 and 114 including their chemical identification. Advanced quantum chemistry calculations of atoms and molecules would be of much help. First experiments with element 112 evidence that the metal is much more volatile and inert than mercury.

  14. Superheavy Element Research at Tasca at GSI

    Science.gov (United States)

    Düllmann, Christoph E.

    2014-09-01

    Experiments on the synthesis of the heaviest elements are in the center of the current research program on superheavy elements at GSI Darmstadt. At the gas-filled recoil separator TASCA, search experiments for the new elements 119 and 120 have been performed in the reactions 50Ti + 249Bk and 50Ti + 249Cf, respectively, and the production of element 117 in the reaction 48Ca + 249Bk was studied. The experiments were performed successfully and the data are currently under analysis.

  15. Measurement of the Survival Probabilities for Hot Fusion Reactions

    CERN Document Server

    Yanez, R; Yao, L; Barrett, J s; Zhu, S; Back, B B; Khoo, T L; Alcorta, M; Albers, M

    2014-01-01

    We have studied the fission-neutron emission competition in highly excited $^{274}$Hs (Z=108) (where the fission barrier is due to shell effects) formed by a hot fusion reaction. Matching cross bombardments ($^{26}$Mg + $^{248}$Cm and $^{25}$Mg + $^{248}$Cm) were used to identify the properties of first chance fission of $^{274}$Hs. A Harding-Farley analysis of the fission neutrons emitted in the $^{25,26}$Mg + $^{248}$Cm was performed to identify the pre- and post-scission components of the neutron multiplicities in each system. ($\\Gamma$$_{n}$/$\\Gamma$$_{t}$) for the first chance fission of $^{274}$Hs (E$^{\\ast}$ = 63 MeV) is 0.89 $\\pm$ 0.13, i.e., $\\sim$ 90 $%$ of the highly excited nuclei survive.The high value of that survival probability is due to dissipative effects during de-excitation. A proper description of the survival probabilities of excited superheavy nuclei formed in hot fusion reactions requires consideration of both dynamic and static (shell-related) effects.

  16. X-ray emission from the nuclei, lobes and hot-gas environments of two FR-II radio galaxies

    CERN Document Server

    Croston, J H; Hardcastle, M J; Worrall, D M

    2004-01-01

    We report the detection of multiple components of X-ray emission from the two FR-II radio galaxies 3C 223 and 3C 284, based on new XMM-Newton observations. We attribute the detected X-ray emission from the lobes of both sources to inverse-Compton scattering of cosmic microwave background photons. With this model, we find that the magnetic field strength in the lobes is at the equipartition value for 3C 284, and within a factor of two of the equipartition value for 3C 223. We also detect group-scale hot atmospheres around both sources, and determine temperatures and pressures in the gas. The lobes of both sources are in pressure balance with the hot-gas environments, if the lobes contain only the synchrotron-emitting particles and the measured magnetic field strength. The core spectra of both sources contain an unabsorbed soft component, likely to be related to the radio jet, and an additional heavily absorbed power-law component. 3C 223 also displays a bright (EW ~ 500 eV) Fe K-alpha emission line.

  17. Systematic study of probable projectile-target combinations for the synthesis of the superheavy nucleus 302120

    Science.gov (United States)

    Santhosh, K. P.; Safoora, V.

    2016-08-01

    Probable projectile-target combinations for the synthesis of the superheavy element 302120 have been studied taking the Coulomb and proximity potential as the interaction barrier. The probabilities of the compound nucleus formation PCN for the projectile-target combinations found in the cold reaction valley of 302120 are estimated. At energies near and above the Coulomb barrier, we have calculated the capture, fusion, and evaporation residue cross sections for the reactions of all probable projectile-target combinations so as to predict the most promising projectile-target combinations for the synthesis of the superheavy element 302120 in heavy-ion fusion reactions. The calculated fusion and evaporation cross sections for the more asymmetric ("hotter") projectile-target combination is found to be higher than the less asymmetric ("colder") combination. It can be seen from the nature of the quasifission barrier height, mass asymmetry, the probability of compound nucleus formation, survival probability, and excitation energy, the systems 44Ar+258No , 46Ar+256No , 48Ca+254Fm , 50Ca+252Fm , 54Ti+248Cf , and 58Cr+244Cm in deep region I of the cold reaction valley and the systems 62Fe+240Pu , 64Fe+238Pu , 68Ni+234U , 70Ni+232U , 72Ni+230U , and 74Zn+228Th in the other cold valleys are identified as the better projectile-target combinations for the synthesis of 302120. Our predictions on the synthesis of 302120 superheavy nuclei using the combinations 54Cr+248Cm , 58Fe+244Pu , 64Ni+238U , and 50Ti+249Cf are compared with available experimental data and other theoretical predictions.

  18. Attempts to produce superheavy elements by fusion of /sup 48/Ca with /sup 248/Cm in the bombarding energy range of 4. 5--5. 2 MeV/u

    Energy Technology Data Exchange (ETDEWEB)

    Armbruster, P.; Agarwal, Y.K.; Bruechle, W.; Bruegger, M.; Dufour, J.P.; Gaggeler, H.; Hessberger, F.P.; Hofmann, S.; Lemmertz, P.; Muenzenberg, G.; Poppensieker, K.; Reisdorf, W.; Schadel, M.; Schmidt, K.; Schneider, J.H.R.; Schneider, W.F.W.; Suemmerer, K.; Vermeulen, D.; Wirth, a.G.; Ghiorso, A.; Gregorich, K.E.; Lee, D.; Leino, M.; Moody, K.J.; Seaborg, G.T.; Welch, R.B.; Wilmarth, P.; Yashita, S.; Frink, C.; Greulich, N.; Herrmann, G.; Hickmann, U.; Hildebrand, N.; Kratz, J.V.; Trautman, N.; Fowler, M.M.; Hoffman, D.C.; Daniels, W.R.; von Gunten, H.R.; Dornhoefer, H.

    1985-02-04

    A search for superheavy elements was made in bombardments of /sup 248/Cm with /sup 48/Ca ions performed at projectile energies close to the interaction barrier in order to keep the excitation energy of the compound nucleus Z = 116, A = 296 as low as possible. No evidence for superheavy nuclei was obtained in a half-life region from 1 ..mu..s to 10 yr with a production cross section greater than 10/sup -34/ to 10/sup -35/ cm/sup 2/. .AE

  19. Beta-delayed fission probabilities of transfermium nuclei, involved in the r-process

    Science.gov (United States)

    Panov, I.; Lutostansky, Yu; Thielemann, F.-K.

    2016-01-01

    For the nucleosynthesis of heavy and superheavy nuclei fission becomes very important when the r-process runs in a very high neutron density environment. In part, fission is responsible for the formation of heavy nuclei due to the inclusion of fission products as new seed nuclei (fission cycling). More than that, beta-delayed fission, along with spontaneous fission, is responsible in the late stages of the r-process for the suppression of superheavy element yields. For beta-delayed fission probability calculations a model description of the beta-strength- functions is required. Extended theoretical predictions for astro-physical applications were provided long ago, and new predictions also for superheavy nuclei with uptodate nuclear input are needed. For the further extension of data to heavier transactinides the models of strength- functions should be modified, taking into account more complicated level schemes. In our present calculations the strength-function model is based on the quasi-particle approximation of Finite Fermi Systems Theory. The probabilities of beta-delayed fission and beta-delayed neutron emission are calculated for some transfermium neutron-rich nuclei, and the influence of beta-delayed fission upon superheavy element formation is discussed.

  20. Shell Correction at the Saddle Point for Superheavy Nucleus

    Institute of Scientific and Technical Information of China (English)

    张炜; 张时声; 张双全; 孟杰

    2003-01-01

    The potential energy surface for superheavy nucleus has been studied within the framework of the constrained relativistic mean field theory, and the shell correction energy as a function of deformation has been extracted by the Strutinsky shell correction procedure. Contrary to the usual expectation, the shell correction energy at the saddle point is too important to be neglected, and it has essential contribution to the fission barrier in superheavy nucleus.

  1. Competition between alpha-decay and spontaneous fission at isotopes of superheavy elements Rf, Db, and Sg

    Energy Technology Data Exchange (ETDEWEB)

    Anghel, Claudia Ioana, E-mail: claudia.anghel@theory.nipne.ro [Department of Theoretical Physics, Horia Hulubei National Institute for Physics and Nuclear Engineering, Magurele, P.O.Box MG-6, RO-077125 (Romania); University of Bucharest, Faculty of Physics, RO-077125 Bucharest - Magurele (Romania); Silisteanu, Andrei Octavian [Radiopharmaceutical Research Center, Horia Hulubei National Institute for Physics and Nuclear Engineering, Magurele, P.O.Box MG-6, RO-077125 (Romania)

    2015-12-07

    The most important decay modes for heavy and superheavy nuclei are their α-decay and spontaneous fission. This work investigates the evolution and the competition of these decay modes in long isotopic sequences. The partial half-lives are given by minimal sets of parameters extracted from the fit of experimental data and theoretical results. A summary of the experimental and calculated α-decay and spontaneous fission half-lives of the isotopes of elements Rf, Db, and Sg is presented. Some half-life extrapolations for nuclides not yet known are also obtained.

  2. An experimental paradigm opening the world of superheavy elements

    Science.gov (United States)

    Armbruster, P.; Münzenberg, Gottfried

    2012-07-01

    The history of the discovery of the six elements Z = 107 ∓ 112, bohrium, hassium, meitnerium, darmstadtium, roentgenium, and copernicium goes back to the early 1960s. An experimental method to separate and identify rare nuclear reaction products, the recoil separation, was developed and optimised for beams of fission products at European research reactors. Chemical elements beyond the then first transactinides ( Z = 104), which owe their stability to the internal structure of atomic nuclei, were predicted theoretically. A big brother of the shell-stabilised nucleus 208Pb, a spherical magic nucleus at Z = 114∓126 and N = 184, might reach lifetimes long enough to be detected. In the seventies, hunting superheavy elements (SHE) was on the agenda of nuclear chemistry. Could the Periodic Table of Elements be extended to Z = 120, and is the order of electrons in the atom still following the laws established for lighter elements? In Germany, the heavy ion accelerator (UNILAC) was built by Christoph Schmelzer and his team at GSI, Darmstadt. SHE and UNILAC met the recoil separators in 1968, and SHIP (Separator for Heavy Ion reaction Products) was ready together with the first UNILAC-beams in 1976. Recoil separation is orders of magnitude more sensitive, selective, and faster than earlier methods used to synthesise elements up to seaborgium, Z = 106. The experimental paradigm we introduced opened the world of SHEs. At SHIP we discovered and investigated the elements Z = 107∓112 in the years 1980-2000. Our laboratory was the world champion during this time. Today our experimental method is used worldwide in the search for SHEs, but the leadership went to the Russian laboratory JINR in Dubna, which extended the Periodic Table by 6 more elements to Z = 118, the candidate for the next rare gas.

  3. Exploration of (super-)heavy elements using the Skyrme-Hartree-Fock model

    Energy Technology Data Exchange (ETDEWEB)

    Erler, Jochen

    2011-01-31

    Motivated by the steadily increasing number of known nuclei and nuclear properties, theories of nuclear structure are presently a field of intense research. This work concentrates on the self-consistent description of nuclei in terms of the Skyrme-Hartree-Fock (SHF) approach. The extrapolation of nuclear shell structure to the region of super-heavy elements (SHE) using the SHF model, the dependence on different parameterization and the influence of collective correlation will be studied. The general scope of this work are large scale calculation for a global survey of properties of SHE like binding energies, separation energies and decay characteristics and lifetimes. These calculations were done in a collaboration with the theory group of the GSI in Darmstadt and have the aim to develop a database of lifetimes and reaction rates for {alpha}, {beta}-decay and spontaneous fission in a very wide range with proton numbers 86 {<=} Z {<=} 120 and neutron numbers up to N {approx} 260 relevant for the astrophysical r-process. The results of this study for example predictions of a possible islands of very stable nuclei and information of favored decay mode for each nuclei are also applicable in the recent experimental synthesis of exotic SHE. For these calculation a framework to calculate {beta}-decay half-lives within the SHF model has been developed and the existing axial SHF code has been extended to compute {beta}-transition matrix elements and so to provide an estimation of half-lives. (orig.)

  4. Exotic nuclei: another aspect of nuclear structure; Les noyaux exotiques: un autre regard sur la structure nucleaire

    Energy Technology Data Exchange (ETDEWEB)

    Dobaczewski, J. [Warsaw Univ., Institute of Theoretical Physics (Poland); Blumenfeld, Y.; Flocard, H.; Garcia Borge, M.J.; Nowacki, F.; Rombouts, S.; Theisen, Ch.; Marques, F.M.; Lacroix, D.; Dessagne, P.; Gaeggeler, H

    2002-07-01

    This document gathers the lectures made at the Joliot Curie international summer school in 2002 whose theme that year was exotic nuclei. There were 11 contributions whose titles are: 1) interactions, symmetry breaking and effective fields from quarks to nuclei; 2) status and perspectives for the study of exotic nuclei: experimental aspects; 3) the pairing interaction and the N = Z nuclei; 4) borders of stability region and exotic decays; 5) shell structure of nuclei: from stability to decay; 6) variational approach of system with a few nucleons; 7) from heavy to super-heavy nuclei; 8) halos, molecules and multi-neutrons; 9) macroscopic approaches for fusion reactions; 10) beta decay: a tool for spectroscopy; 11) the gas phase chemistry of super-heavy elements.

  5. Product PCNPsurv or the "reduced" evaporation residue cross section σER/σfusion for "hot" fusion reactions studied with the dynamical cluster-decay model

    Science.gov (United States)

    Chopra, Sahila; Kaur, Arshdeep; Hemdeep, Gupta, Raj K.

    2016-04-01

    The product PCNPsurv of compound nucleus (CN) fusion probability PCN and survival probability Psurv is calculated to determine the reduced evaporation residue cross section σER/σfusion , denoted σERreduced, with (total) fusion cross section σfusion given as a sum of CN-formation cross section σCN and non-CN cross section σnCN for each reaction, where σCN is the sum of evaporation residue cross section σER and fusion-fission cross section σff and σnCN, if not measured, is estimated empirically as the difference between measured and calculated σfusion. Our calculations of PCN and Psurv, based on the dynamical cluster-decay model, were successfully made for some 17 "hot" fusion reactions, forming different CN of mass numbers ACN˜100 -300 , with deformations of nuclei up to hexadecapole deformations and "compact" orientations for both coplanar (Φc=0∘ ) and noncoplanar (Φc≠0∘ ) configurations, using various different nuclear interaction potentials. Interesting variations of σERreduced with CN excitation energy E*, fissility parameter χ , CN mass ACN, and Coulomb parameter Z1Z2 show that, independent of entrance channel, different isotopes of CN, and nuclear interaction potentials used, the dominant quantity in the product is Psurv, which classifies all the studied CN into three groups of weakly fissioning, radioactive, and strongly fissioning superheavy nuclei, with relative magnitudes of σERreduced˜1 , ˜10-6 , and ˜10-11 , which, like for PCN, get further grouped in two dependencies of (i) weakly fissioning and strongly fissioning superheavy nuclei decreasing with increasing E* and (ii) radioactive nuclei increasing with increasing E*.

  6. Superheavy thermal dark matter and primordial asymmetries

    Science.gov (United States)

    Bramante, Joseph; Unwin, James

    2017-02-01

    The early universe could feature multiple reheating events, leading to jumps in the visible sector entropy density that dilute both particle asymmetries and the number density of frozen-out states. In fact, late time entropy jumps are usually required in models of Affleck-Dine baryogenesis, which typically produces an initial particle-antiparticle asymmetry that is much too large. An important consequence of late time dilution, is that a smaller dark matter annihilation cross section is needed to obtain the observed dark matter relic density. For cosmologies with high scale baryogenesis, followed by radiation-dominated dark matter freeze-out, we show that the perturbative unitarity mass bound on thermal relic dark matter is relaxed to 1010 GeV. We proceed to study superheavy asym-metric dark matter models, made possible by a sizable entropy injection after dark matter freeze-out, and identify how the Affleck-Dine mechanism would generate the baryon and dark asymmetries.

  7. Isotope Dependence of Superheavy Nucleus Formation Cross Section

    Institute of Scientific and Technical Information of China (English)

    LIU Zu-Hua; BAG Jing-Dong

    2006-01-01

    The dynamical process in the superheavy nucleus synthesis is studied on the basis of the two-dimensional Smolu-chowski equation. Special attention is paid to the isotope dependence of the cross section for the superheavy nucleus formation by means of making a comparison among the reaction systems of 54Fe + 204Pb, 56Fe + 206Pb, and 58Fe + 208Pb. It is found by this comparison that the formation cross section is very sensitive to the conditional saddle-point height and the neutron separation energy of the compound nucleus. Reaction systems with lower height of conditional saddle-point and smaller neutron separation energy are more favourable for the synthesis of the superheavy nucleus.

  8. Superheavy Dark Matter in Light of Dark Radiation

    CERN Document Server

    Park, Jong-Chul

    2014-01-01

    Superheavy dark matter can satisfy the observed dark matter abundance if the stability condition is fulfilled. Here, we propose a new Abelian gauge symmetry ${\\rm U(1)}_H$ for the stability of superheavy dark matter as the electromagnetic gauge symmetry to the electron. The new gauge boson associated with ${\\rm U(1)}_H$ contributes to the effective number of relativistic degrees of freedom in the universe as dark radiation, which has been recently measured by several experiments, e.g., PLANCK. We calculate the contribution to dark radiation from the decay of a scalar particle via the superheavy dark matter in the loop. Interestingly enough, this scenario will be probed by a future LHC run in the invisible decay signatures of the Higgs boson.

  9. Higgs interchange and bound states of superheavy fermions

    Indian Academy of Sciences (India)

    M De Sanctis

    2013-09-01

    Hypothetical superheavy fourth-generation fermions with a very small coupling with the rest of the Standard Model can give rise to long enough lived bound states. The production and the detection of these bound states would be experimentally feasible at the LHC. Extending, in the present study, the analysis of other authors, a semirelativistic wave equation is solved using an accurate numerical method to determine the binding energies of these possible superheavy fermion-bound states. The interaction given by the Yukawa potential of the Higgs boson exchange is considered; the corresponding relativistic corrections are calculated by means of a model based on the covariance properties of the Hamiltonian. We study the effects given by the Coulomb force. Moreover, we calculate the contributions given by the Coulombic and confining terms of the strong interaction in the case of superheavy quark bound states. The results of the model are critically analysed.

  10. Spontaneous fission of superheavy nucleus $^{286}$Fl

    CERN Document Server

    Poenaru, Dorin N

    2016-01-01

    The decimal logarithm of spontaneous fission half-life of the superheavy nucleus $^{286}$Fl experimentally determined is $\\log_{10} T_f^{exp} (s) = -0.632$. We present a method to calculate the half-life based on the cranking inertia and the deformation energy, functions of two independent surface coordinates, using the best asymmetric two center shell model. In the first stage we study the statics. At a given mass asymmetry up to about $\\eta=0.5$ the potential barrier has a two hump shape, but for larger $\\eta$ it has only one hump. The touching point deformation energy versus mass asymmetry shows the three minima, produced by shell effects, corresponding to three decay modes: spontaneous fission, cluster decay and $\\alpha$~decay. The least action trajectory is determined in the plane $(R,\\eta)$ where $R$ is the separation distance of the fission fragments and $\\eta$ is the mass asymmetry. We may find a sequence of several trajectories one of which gives the least action. The parametrization with two deforma...

  11. Two-body dissipation effects on synthesis of superheavy elements

    CERN Document Server

    Tohyama, M

    2015-01-01

    To investigate the two-body dissipation effects on the synthesis of superheavy elements, we calculate low-energy collisions of the $N=50$ isotones ($^{82}$Ge, $^{84}$Se, $^{86}$Kr and $^{88}$Sr) on $^{208}$Pb using the time-dependent density-matrix theory (TDDM). TDDM is an extension of the time-dependent Hartree-Fock (TDHF) theory and can determine the time evolution of one-body and two-body density matrices. Thus TDDM describes both one-body and two-body dissipation of collective energies. It is shown that the two-body dissipation may increase fusion cross sections and enhance the synthesis of superheavy elements.

  12. RELATIVISTIC CALCULATIONS OF THE SUPERHEAVY NUCLEUS 114-298

    NARCIS (Netherlands)

    BOERSMA, HF

    1993-01-01

    We investigate ground-state properties of the superheavy nucleus with N = 184 and Z = 114, (298)114, using conventional relativistic mean-field theory and density-dependent mean-field theory, which reproduces Dirac-Brueckner calculations in nuclear matter. Our calculations provide support for N = 18

  13. Alpha-decay properties of superheavy elements $Z=113-125$ in the relativistic mean-field theory with vector self-coupling of $\\omega$ meson

    CERN Document Server

    Sharma, M M; Münzenberg, G

    2004-01-01

    We have investigated properties of $\\alpha$-decay chains of recently produced superheavy elements Z=115 and Z=113 using the new Lagrangian model NL-SV1 with inclusion of the vector self-coupling of $\\omega$ meson in the framework of the relativistic mean-field theory. It is shown that the experimentally observed alpha-decay energies and half-lives are reproduced well by this Lagrangian model. Further calculations for the heavier elements with Z=117-125 show that these nuclei are superdeformed with a prolate shape in the ground state. A superdeformed shell-closure at Z=118 lends an additional binding and an extra stability to nuclei in this region. Consequently, it is predicted that the corresponding $Q_\\alpha$ values provide $\\alpha$-decay half-lives for heavier superheavy nuclei within the experimentally feasible conditions. The results are compared with those of macroscopic-microscopic approaches. A perspective of the difference in shell effects amongst various approaches is presented and its consequences o...

  14. Non-thermal leptogenesis with almost degenerate superheavy neutrinos

    CERN Document Server

    Allahverdi, R; Allahverdi, Rouzbeh; Mazumdar, Anupam

    2003-01-01

    We present a model with minimal assumptions for non-thermal leptogenesis with almost degenerate superheavy right-handed neutrinos in a supersymmetric set up. In this scenario a gauge singlet inflaton is directly coupled to the right-handed (s)neutrinos with a mass heavier than the inflaton mass. This helps avoiding potential problems which can naturally arise otherwise. The inflaton decay to the Standard Model leptons and Higgs, via off-shell right-handed (s)neutrinos, reheats the Universe. The same channel is also responsible for generating the lepton asymmetry, thus requiring no stage of preheating in order to excite superheavy right-handed (s)neutrinos. The suppressed decay rate of the inflaton naturally leads to a sufficiently low reheat temperature, which in addition, prevents any wash out of the yielded asymmetry. Finally, a successful leptogenesis can be accommodated for a variety of inflationary models with a rather wide ranging inflationary scale.

  15. Probing superheavy quasimolecular collisions with incoming inner shell vacancies

    Energy Technology Data Exchange (ETDEWEB)

    Verma, P. [Atomphysik, GSI, Planckstrasse 1, D-64291 Darmstadt (Germany) and JMI University, New Delhi (India) and Vaish College, Rohtak (India)]. E-mail: P.Verma@gsi.de; Mokler, P.H. [Atomphysik, GSI, Planckstrasse 1, D-64291 Darmstadt (Germany); J. Liebig University, Giessen (Germany); Braeuning-Demian, A. [Atomphysik, GSI, Planckstrasse 1, D-64291 Darmstadt (Germany); Braeuning, H. [J. Liebig University, Giessen (Germany); Kozhuharov, C. [Atomphysik, GSI, Planckstrasse 1, D-64291 Darmstadt (Germany); Bosch, F. [Atomphysik, GSI, Planckstrasse 1, D-64291 Darmstadt (Germany); Liesen, D. [Atomphysik, GSI, Planckstrasse 1, D-64291 Darmstadt (Germany); Hagmann, S. [Atomphysik, GSI, Planckstrasse 1, D-64291 Darmstadt (Germany); J.W. Goethe University, Frankfurt (Germany); Stoehlker, Th. [Atomphysik, GSI, Planckstrasse 1, D-64291 Darmstadt (Germany); Stachura, Z. [Institute for Nuclear Physics, Cracow (Poland); Banas, D. [Atomphysik, GSI, Planckstrasse 1, D-64291 Darmstadt (Germany); Swietokrzyska Academy, Kielce (Poland); Orsic-Muthig, A. [Atomphysik, GSI, Planckstrasse 1, D-64291 Darmstadt (Germany); Schoeffler, M. [J.W. Goethe University, Frankfurt (Germany); Sierpowski, D. [Jagellonian University, Cracow (Poland); Spillmann, U. [Atomphysik, GSI, Planckstrasse 1, D-64291 Darmstadt (Germany); Tashenov, S. [Atomphysik, GSI, Planckstrasse 1, D-64291 Darmstadt (Germany); Toleikis, S. [Atomphysik, GSI, Planckstrasse 1, D-64291 Darmstadt (Germany); Wahab, M.A. [JMI University, New Delhi (India)

    2006-04-15

    With the advanced accelerator technologies used at the SIS/ESR heavy ion facility at GSI, the highest charge states (bare, H-like, etc.) even for the heaviest ions can be provided for experiments at moderate collision velocities (v {sub ion} < v {sub K}). Hence, inner shell vacancies can be provided prior to collisions for the innermost shells of transiently formed superheavy quasimolecules. However, projectile K-vacancies may be destroyed while penetrating solids. The goal of the present investigation is to establish how far at relatively low collision velocities, high incoming ionic charge states do survive in thin solid targets and hence, how far thin solid targets can be utilized for studying superheavy quasimolecules with well-defined, open, incoming, inner shell vacancy channels. The dependence of quasimolecular collisions on projectile charge state (q) and target thickness (t) is studied in very thin Au solid targets for 69 MeV/u U {sup q+} ions (73 {<=} q {<=} 91)

  16. Synthesis and Chemical Properties of Superheavy Elements%超重元素的合成及其化学性质

    Institute of Scientific and Technical Information of China (English)

    秦芝; 范芳丽; 吴晓蕾; 白静; 丁华杰; 雷富安; 田伟; 郭俊盛

    2011-01-01

    超重元素是指原子序数大于等于104号的元素,超重元素的研究是目前核物理和核化学领域的前沿课题之一。本文介绍了当前国际上超重元素合成的最新进展,包括三种合成方法——"热熔合"、"冷熔合"和"温熔合"以及最新的超重元素117号元素的合成,同时详细介绍了108号和112号元素的化学性质研究的实验进展情况,并对超重元素的未来发展进行展望。%Superheavy elements are those with high atomic number,beginning with element 104(Rf).The research of superheavy elements is frontier topics in nuclear physics and nuclear chemistry.The present status of synthesis of superheavy elements is introduced,including the three synthesis methods——"hot fusion","cold-fusion" and "warm fusion" and the discovery of a new chemical element with atomic number Z=117.The current experimental studies of gas chemistry of element 108 and element 112 are discussed in detail.The prospects of the development of superheavy elements are reviewed.

  17. Nuclear mass formula with shell energies obtained by a new method and its application to superheavy elements

    Energy Technology Data Exchange (ETDEWEB)

    Koura, H.; Uno, M.; Tachibana, T.; Yamada, M. [Waseda Univ., Advanced Research Institute for Science and Engineering, Tokyo (Japan)

    2000-03-01

    A nuclear mass formula is constructed which is composed of two parts, one describing the general trend of the masses as a function of Z and N and the other representing deviations of individual masses from this general trend. These deviations, referred to as shell energies, are calculated by a new method for spherical as well as deformed nuclei only with use of spherical single-particle potentials. The root-mean-square deviation from experimentally known masses is 0.68 MeV. The obtained mass formula, is applicable to any nucleus with Z {>=} 2 and N {>=} 2. By this mass formula {alpha}-decay energies are calculated, and {alpha}-decay half-lives of superheavy elements are estimated. (author)

  18. Possible Way to Synthesize Superheavy Element Z=117

    OpenAIRE

    Zhao-Qing, Feng; Gen-Ming, Jin; Ming-Hui, Huang; Zai-Guo, Gan; Nan, Wang; Jun-Qing, Li

    2007-01-01

    Within the framework of the dinuclear system model, the production of superheavy element Z=117 in possible projectile-target combinations is analyzed systematically. The calculated results show that the production cross sections are strongly dependent on the reaction systems. Optimal combinations, corresponding excitation energies and evaporation channels are proposed in this letter, such as the isotopes ^{248,249}Bk in ^{48}Ca induced reactions in 3n evaporation channels and the reactions ^{...

  19. Prospects of heavy and superheavy element production via inelastic nucleus-nucleus collisions - from 238U+238U to18O+254Es

    Science.gov (United States)

    Schädel, Matthias

    2016-12-01

    Multi-nucleon transfer reactions, frequently termed deep-inelastic, between heavy-ion projectiles and actinide targets provide prospects to synthesize unknown isotopes of heavy actinides and superheavy elements with neutron numbers beyond present limits. The 238U on 238U reaction, which revealed essential aspects of those nuclear reactions leading to surviving heavy nuclides, mainly produced in 3n and 4n evaporation channels, is discussed in detail. Positions and widths of isotope distributions are compared. It is shown, as a general rule, that cross sections peak at irradiation energies about 10% above the Coulomb barrier. Heavy target nuclei are essential for maximizing cross sections. Experimental results from the 238U on 248Cm reaction, including empirical extrapolations, are compared with theoretical model calculations predicting relatively high cross sections for neutron-rich nuclei. Experiments to test the validity of such predictions are proposed. Comparisons between rather symmetric heavy-ion reactions like 238U on 248Cm (or heavier targets up to 254Es) with very asymmetric ones like 18O on 254Es reveal that the ones with 238U as a projectile have the highest potential in the superheavy element region while the latter ones can be advantageous for the synthesis of heavy actinide isotopes. Concepts for highly efficient recoil separators designed for transfer products are presented.

  20. Neutron and proton shell closure in the superheavy region via cluster radioactivity in 280−314 116 isotopes

    Indian Academy of Sciences (India)

    K P Santhosh; R K Biju

    2009-04-01

    Based on the concept of cold valley in fission and fusion, the radioactive decay of superheavy280−314116 nuclei was studied taking Coulomb and proximity potentials as the interacting barrier. It is found that the inclusion of proximity potential does not change the position of minima but minima become deeper which agrees with the earlier findings of Gupta and co-workers. In addition to alpha particle minima, the other deepest minima occur for 8Be, 12,14C clusters. In the fission region two deep regions are found each consisting of several comparable minima, the first region centred on 208Pb and the second is around 132Sn. The cluster decay half-lives and other characteristics are computed for various clusters ranging from alpha particle to 70Ni. The computed half-lives for alpha decay match with the experimental values and with the values calculated using Viola–Seaborg–Sobiczewski (VSS) systematic. The plots connecting computed values and half-lives against neutron number of daughter nuclei were studied for different clusters and it is found that the next neutron shell closures occur at = 162, 172 and 184. Isotopic and isobaric mass parabolas are studied for various cluster emissions and minima of parabola indicate neutron shell closure at = 162, 184 and proton shell closure at = 114. Our study shows that $^{276}_{162}$114 is the deformed doubly magic and $^{298}_{184}$114 is the spherical doubly magic nuclei.

  1. Decay properties of heavier nuclei and mass formula

    Energy Technology Data Exchange (ETDEWEB)

    Uno, Masahiro [Ministry of Education, Science and Culture, Tokyo (Japan)

    2000-03-01

    The stabilities of heavy nuclei, including super-heavy elements, are governed by alpha decay and fission. Some exotic types of decay, such as heavy cluster decay, which does not occur so frequently as to govern stability, have been also reported. The half-time estimations of various types of decay are reviewed. And the possibility of decay, mainly in case of heavy cluster decay, is discussed with Q-value obtained from mass formulae as well. Some topics concerning other types of exotic decay are presented. Recent trends in the research on mass formula are reviewed from the historical point of view, to get perspectives of future development. (Yamamoto, A.)

  2. First online multireflection time-of-flight mass measurements of isobar chains produced by fusion-evaporation reactions: Toward identification of superheavy elements via mass spectroscopy

    Science.gov (United States)

    Schury, P.; Wada, M.; Ito, Y.; Kaji, D.; Arai, F.; MacCormick, M.; Murray, I.; Haba, H.; Jeong, S.; Kimura, S.; Koura, H.; Miyatake, H.; Morimoto, K.; Morita, K.; Ozawa, A.; Rosenbusch, M.; Reponen, M.; Söderström, P.-A.; Takamine, A.; Tanaka, T.; Wollnik, H.

    2017-01-01

    Using a multireflection time-of-flight mass spectrograph located after a gas cell coupled with the gas-filled recoil ion separator GARIS-II, the masses of several α -decaying heavy nuclei were directly and precisely measured. The nuclei were produced via fusion-evaporation reactions and separated from projectilelike and targetlike particles using GARIS-II before being stopped in a helium-filled gas cell. Time-of-flight spectra for three isobar chains, 204Fr-204Rn-204At-204Po , 205Fr-205Rn-205At-205Po-205Bi , and 206Fr-206Rn-206At , were observed. Precision atomic mass values were determined for Fr-206204, Rn,205204, and At,205204. Identifications of 205Bi, Po,205204, 206Rn, and 206At were made with N ≲10 detected ions, representing the next step toward use of mass spectrometry to identify exceedingly low-yield species such as superheavy element ions.

  3. Constraining the equation of state of nuclear matter from fusion hindrance in reactions leading to the production of superheavy elements

    Science.gov (United States)

    Veselsky, M.; Klimo, J.; Ma, Yu-Gang; Souliotis, G. A.

    2016-12-01

    The mechanism of fusion hindrance, an effect preventing the synthesis of superheavy elements in the reactions of cold and hot fusion, is investigated using the Boltzmann-Uehling-Uhlenbeck equation, where Coulomb interaction is introduced. A strong sensitivity is observed both to the modulus of incompressibility of symmetric nuclear matter, controlling the competition of surface tension and Coulomb repulsion, and to the stiffness of the density-dependence of symmetry energy, influencing the formation of the neck prior to scission. The experimental fusion probabilities were for the first time used to derive constraints on the nuclear equation of state. A strict constraint on the modulus of incompressibility of nuclear matter K0=240 -260 MeV is obtained while the stiff density-dependences of the symmetry energy (γ >1 ) are rejected.

  4. The AKARI 2.5-5.0 Micron Spectral Atlas of Type-1 Active Galactic Nuclei: Black Hole Mass Estimator, Line Ratio, and Hot Dust Temperature

    CERN Document Server

    Kim, Dohyeong; Kim, Ji Hoon; Jun, Hyunsung David; Woo, Jong-Hak; Lee, Hyung Mok; Lee, Myung Gyoon; Nakagawa, Takao; Matsuhara, Hideo; Wada, Takehiko; Oyabu, Shinki; Takagi, Toshinobu; Ohyama, Youichi; Lee, Seong-Kook

    2015-01-01

    We present 2.5-5.0 $\\mu$m spectra of 83 nearby ($0.002\\,<\\,z\\,<\\,0.48$) and bright ($K<14$mag) type-1 active galactic nuclei (AGNs) taken with the Infrared Camera (IRC) on board $\\it{AKARI}$. The 2.5-5.0 $\\mu$m spectral region contains emission lines such as Br$\\beta$ (2.63 $\\mu$m), Br$\\alpha$ (4.05 $\\mu$m), and polycyclic aromatic hydrocarbons (PAH; 3.3 $\\mu$m), which can be used for studying the black hole (BH) masses and star formation activities in the host galaxies of AGNs. The spectral region also suffers less dust extinction than in the ultra violet (UV) or optical wavelengths, which may provide an unobscured view of dusty AGNs. Our sample is selected from bright quasar surveys of Palomar-Green (PG) and SNUQSO, and AGNs with reverberation-mapped BH masses from Peterson et al. (2004). Using 11 AGNs with reliable detection of Brackett lines, we derive the Brackett-line-based BH mass estimators. We also find that the observed Brackett line ratios can be explained with the commonly adopted physica...

  5. Possible Way to Synthesize Superheavy Element Z=117

    CERN Document Server

    Zhao-Qing, Feng; Ming-Hui, Huang; Zai-Guo, Gan; Nan, Wang; Jun-Qing, Li

    2007-01-01

    Within the framework of the dinuclear system model, the production of superheavy element Z=117 in possible projectile-target combinations is analyzed systematically. The calculated results show that the production cross sections are strongly dependent on the reaction systems. Optimal combinations, corresponding excitation energies and evaporation channels are proposed in this letter, such as the isotopes ^{248,249}Bk in ^{48}Ca induced reactions in 3n evaporation channels and the reactions ^{45}Sc+^{246,248}Cm in 3n and 4n channels, and the system ^{51}V+^{244}Pu in 3n channel.

  6. Possible Way to Synthesize Superheavy Element Z = 117

    Institute of Scientific and Technical Information of China (English)

    FENG Zhao-Qing; JIN Gen-Ming; HUANG Ming-Hui; GAN Zai-Guo; WANG Nan; LI Jun-Qing

    2007-01-01

    Within the framework of the dinuclear system model, the production of superheavy element Z = 117 in possible projectile-target combinations is analysed systematically. The calculated results show that the production cross sections are strongly dependent on the reaction systems. Optimal combinations, corresponding excitation energies and evaporation channels are proposed, such as the isotopes 248,249Bk in 48Ca induced reactions in 3n evaporation channels and the reactions 45Sc+246,248Cm in 3n and 4n channels, and the system 51V+244pu in 3n channel.

  7. Ultra High Energy Cosmic Rays & Super-heavy Dark Matter

    CERN Document Server

    Marzola, Luca

    2016-01-01

    We reanalyse the prospects for upcoming Ultra-High Energy Cosmic Ray experiments in connection with the phenomenology of Super-heavy Dark Matter. We identify a set of observables well suited to reveal a possible anisotropy in the High Energy Cosmic Ray flux induced by the decays of these particles, and quantify their performance via Monte Carlo simulations that mimic the outcome of near-future and next-generation experiments. The spherical and circular dipoles are able to tell isotropic and anisotropic fluxes apart at a confidence level as large as $4\\sigma$ or $5\\sigma$, depending on the Dark Matter profile. The forward-to-backward flux ratio yields a comparable result for relatively large opening angles of about 40~deg, but it is less performing once a very large number of events is considered. We also find that an actual experiment employing these observables and collecting 300~events at 60~EeV would have a $50\\%$ chance of excluding isotropy against Super-heavy Dark Matter at a significance of at least $3...

  8. Status and perspectives of the Dubna superheavy element factory

    Science.gov (United States)

    Dmitriev, Sergey; Itkis, Mikhail; Oganessian, Yuri

    2016-12-01

    In the Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research (FLNR JINR), construction of a new experimental complex is currently in progress (Superheavy Element Factory), aimed at the synthesis of new superheavy nuclides and the detailed study of those already synthesized. The project includes the construction of a new accelerator of stable and long-lived isotopes in the mass range A = 10-100 with an intensity of up to 10 pμ A and energy up to 8 MeV/nucleon; con-struction of a new experimental building and infrastructure for housing the accelerator with five channels for the transportation of beams to a 1200-m2 experimental hall that is equipped with systems of shielding and control for operations with radioactive materials; development of new separators of reaction products; upgrade of the existing separators and development of the new detection modules for the study of nuclear, atomic, and chemical properties of new elements. The first experiments are planned for 2018.

  9. Super-Heavy Dark Matter - Towards Predictive Scenarios from Inflation

    CERN Document Server

    Kannike, Kristjan; Raidal, Martti

    2016-01-01

    A generic prediction of the Coleman-Weinberg inflation is the existence of a heavy particle sector whose interactions with the inflaton, the lightest state in this sector, generate the inflaton potential at loop level. For typical interactions the heavy sector may contain stable states whose relic abundance is generated at the end of inflation by the gravity alone. This general feature, and the absence of any particle physics signal of dark matter so far, call for a paradigm shift in the dark sector physics. Accordingly, the dark matter is heavier than the inflaton, its existence follows from the inflaton dynamics, and its abundance today is naturally determined by the weakness of gravitational interaction. This implies that the super-heavy dark matter scenarios can be tested via the measurements of inflationary parameters and/or the CMB isocurvature perturbations and non-Gaussianities. We explicitly work out details of three Coleman-Weinberg inflation scenarios, study the systematics of super-heavy dark matt...

  10. Shell effect and capture cross sections in the synthesis of superheavy nuclei

    Institute of Scientific and Technical Information of China (English)

    DU SaiSai; BIAN BaoAn; LIU Min; FENG ZhaoQing; ZHANG FengShou

    2009-01-01

    The shell effect is included in the improved isospin dependent quantum molecular dynamics model in which the shell correction energy of the system is calculated by using the deformed two-center shell model.A switch function is introduced to connect the shell correction energy of the projectile and the target with that of the compound nucleus during the dynamical fusion process.It is found that the calculated capture cross sections reproduce the experimental data quantitatively at the energy near the Coulomb barrier.The capture cross sections for reaction 8035Br+20882Pb→288117X are also calculated and discussed.

  11. Shell effect and capture cross sections in the synthesis of superheavy nuclei

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The shell effect is included in the improved isospin dependent quantum molecular dynamics model in which the shell correction energy of the system is calculated by using the deformed two-center shell model.A switch function is introduced to connect the shell correction energy of the projectile and the target with that of the compound nucleus during the dynamical fusion process.It is found that the calculated capture cross sections reproduce the experimental data quantitatively at the energy near the Coulomb barrier.The capture cross sections for reaction 8305 Br + 28028 Pb → 121878X are also calculated and discussed.

  12. ORNL actinide materials and a new detection system for superheavy nuclei

    Directory of Open Access Journals (Sweden)

    Rykaczewski Krzysztof P.

    2016-01-01

    Full Text Available The actinide resources and production capabilities at Oak Ridge National Laboratory (ORNL are reviewed, including potential electromagnetic separation of rare radioactive materials. The first experiments at the Dubna Gas Filled Recoil Separator (DGFRS with a new digital detection system developed at ORNL and University of Tennessee Knoxville (UTK are presented. These studies used 240Pu material provided by ORNL and mixed-Cf targets made at ORNL. The proposal to use an enriched 251Cf target and a large dose of 58Fe beam to reach the N = 184 shell closure and to observe new elements with Z = 124, 122 and 120 is discussed.

  13. Upper Limit of the Periodic Table and Synthesis of Superheavy Elements

    Directory of Open Access Journals (Sweden)

    Khazan A.

    2007-04-01

    Full Text Available For the first time, using the heaviest possible element, the diagram for known nuclides and stable isotopes is constructed. The direction of search of superheavy elements is indicated. The Periodic Table with an eighth period is tabulated.

  14. Upper Limit of the Periodic Table and Synthesis of Superheavy Elements

    OpenAIRE

    Khazan A.

    2007-01-01

    For the first time, using the heaviest possible element, the diagram for known nuclides and stable isotopes is constructed. The direction of search of superheavy elements is indicated. The Periodic Table with an eighth period is tabulated.

  15. Search for superheavy-element decay in samples of Madagascar monazite

    Energy Technology Data Exchange (ETDEWEB)

    Ketelle, B.H.; O' Kelley, G.D.; Stoughton, R.W.; Halperin, J.

    1976-12-27

    Two samples of Madagascar monazite from the same geological formation as the biotite studied by Gentry et al. were examined by using a neutron multiplicity counter capable of detecting binary or ternary spontaneous fission decay in any element. No events characteristic of spontaneous fission decay of superheavy elements were found. Derived limits indicate that if superheavy elements were present, then their spontaneous fission half-lives must be extremely long or their concentrations extremely small. (AIP)

  16. Ionization potentials of superheavy elements No, Lr, and Rf and their ions

    Science.gov (United States)

    Dzuba, V. A.; Safronova, M. S.; Safronova, U. I.; Kramida, A.

    2016-10-01

    We predict ionization potentials of superheavy elements No, Lr, and Rf and their ions using a relativistic hybrid method that combines configuration interaction (CI) with the linearized coupled-cluster approach. Extensive study of the completeness of the four-electron CI calculations for Hf and Rf was carried out. As a test of theoretical accuracy, we also calculated ionization potential of Yb, Lu, Hf, and their ions, which are homologues of the superheavy elements of this study.

  17. Compound nucleus formation probability PCN determined within the dynamical cluster-decay model for various "hot" fusion reactions

    Science.gov (United States)

    Kaur, Arshdeep; Chopra, Sahila; Gupta, Raj K.

    2014-08-01

    The compound nucleus (CN) fusion/formation probability PCN is defined and its detailed variations with the CN excitation energy E*, center-of-mass energy Ec .m., fissility parameter χ, CN mass number ACN, and Coulomb interaction parameter Z1Z2 are studied for the first time within the dynamical cluster-decay model (DCM). The model is a nonstatistical description of the decay of a CN to all possible processes. The (total) fusion cross section σfusion is the sum of the CN and noncompound nucleus (nCN) decay cross sections, each calculated as the dynamical fragmentation process. The CN cross section σCN is constituted of evaporation residues and fusion-fission, including intermediate-mass fragments, each calculated for all contributing decay fragments (A1, A2) in terms of their formation and barrier penetration probabilities P0 and P. The nCN cross section σnCN is determined as the quasi-fission (qf) process, where P0=1 and P is calculated for the entrance-channel nuclei. The DCM, with effects of deformations and orientations of nuclei included in it, is used to study the PCN for about a dozen "hot" fusion reactions forming a CN of mass number A ˜100 to superheavy nuclei and for various different nuclear interaction potentials. Interesting results are that PCN=1 for complete fusion, but PCNPCN≪1 due to the nCN contribution, depending strongly on different parameters of the entrance-channel reaction but found to be independent of the nuclear interaction potentials used.

  18. Estimation of atomic masses of heavy and superheavy elements

    Energy Technology Data Exchange (ETDEWEB)

    Uno, Masahiro [Ministry of Education, Science and Culture, Tokyo (Japan)

    1997-07-01

    To estimate unknown atomic masses of heavy and superheavy elements, three kinds of formula: FRDM (finite range droplet model by Moeller et al.), TUYY (an empirical formula by Tachibana et al.) and our KUTY are explained. KUTY estimates the crude shell energies of spherical nucleus from sum of single-particle energies. Then, the refined shell energies in due consideration of paring and deformation are obtained by mixing with the functions of the crude shell energies. Experimental values of U and Fm isotopes were compared with estimation mass of KUTY and FRDM. In the field with experimental values of U isotopes, the value of KUTY and FRDM separated the same difference from the experimental value. The behavior of KUTY and FRDM for Fm isotopes were same as that of U, but ETFSI deviated a little from the experimental values. (S.Y.)

  19. Fission and Properties of Neutron-Rich Nuclei - Proceedings of the Second International Conference

    Science.gov (United States)

    Hamilton, J. H.; Phillips, W. R.; Carter, H. K.

    The Table of Contents for the book is as follows: * Preface * Structure of Elementary Matter: Cold Valleys and Their Importance in Fission, Fusion and for Superheavy Nuclei * Tunnelling Phenomena in Nuclear Physics * Heavy Nuclei Studies Using Transfer Reactions * Isomeric Properties of Nuclei Near 78Ni * Investigation of Light Actinide Nuclei at Yale and Beyond * U-Projectile Fission at Relativistic Energies * Cluster Description of Cold Fission Modes in 252Cf * Neutron-pair Transfer Theory for Pear-shaped Ba Fission Fragments * New RMFA Parameters of Normal and Exotic Nuclei * Study of Fission Fragments from 12C+238U Reactions: Prompt and Delayed Spectroscopy * γ-Ray Angular Correlations in 252Cf and 248Cm Fission Fragments * Fragment Angular Momentum and Descent Dynamics in 252Cf Spontaneous Fission * The Experimental Investigation of Neutron-Rich Nuclei * High-Spin Structure of Some Odd-Z Nuclei with A ≈ 100 From Heavy-Ion Induced Fission * Coexistence of Symmetric and Asymmetric Nuclear Shapes and 10Be Ternary Fission * Octupole Effects in the Lanthanides * High Spin Structure of the 113-1l6Cd Isotopes Produced by Heavy-Ion Induced Fission Reaction * Temperature-Dependent Fission Barriers and Mass Distributions for 239U * Strength Distributions for Gamow Teller Transitions in Very Weakly Bound Systems * High Spin Fragmentation Spectroscopy * Search for a Four-Neutron Transfer From 8He to 4He * Microsecond Isomers in Fission Fragments in the Vicinity of the Doubly Magic 132Sn * Recent On-Line NMR/on Nuclear Magnetic Dipole Moments Near 132Sn: Meson Exchange Current Effects at the Shell Closure and Shell Model Treatment of Variation with Proton and Neutron Number * High-spin K-Isomers Beyond the Fusion Limit * High Energy Neutron Induced Fission: Charge Yield Distributions and Search and Spectroscopy of New Isomers * Hartree-Fock Mean-Field Models Using Separable Interactions * Variation of Fission Characteristics Over the Nuclear Chart * Investigation of

  20. Collective excitations in nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Chomaz, Ph. [Grand Accelerateur National d`Ions Lourds (GANIL), 14 - Caen (France); Collaboration: La Direction des Sciences de la Matiere du CEA (FR); Le Fonds National de la Recherche Scientifique de Belgique (BE)

    1998-12-31

    The properties of the nucleus cannot be reduced to the properties of its constituents: it is a complex system. The fact that many properties of the nucleus are consequences of the existence of mean-field potential is a manifestation of this complexity. In particular, the nucleons can thus self-organize in collective motions such as giant resonances. Therefore the study of this collective motions is a very good tool to understand the properties of the nucleus itself. The purpose of this article is to stress some aspects of these collective vibrations. We have studied how an ensemble of fermions as the nucleus can self-organize in collective vibrations which are behaving like a gas of bosons in weak interaction. Understanding of these phenomena remains one of the important subjects of actuality in the context of quantal systems in strong interaction. In particular, the study of the states with one or two vibration quanta provides a direct information on the structure of nuclei close to their ground states. Moreover, some collective states appear to be very robust against the onset of chaos. This is the case of the hot giant dipole built on top of a hot nucleus which seems to survive up to rather high temperatures. Their sudden disappearance is still a subject of controversy. It may be that the mean-field and the associated collective states are playing a crucial role also in catastrophic processes such as the phase-transitions. Indeed, when the system is diluted the collective vibrations may become unstable and it seems that these unstable modes provide a natural explanation to the self organization of the system in drops. Finally, considering the diversity of the different structures of exotic nuclei one may expect new vibration types. All these studies are showing the diversity of the collective motions of strongly correlated quantum systems such as the nucleus but many open questions remain to be solved. (authors) 304 refs., 53 figs., 5 tabs.

  1. Fusion probability in heavy nuclei

    Science.gov (United States)

    Banerjee, Tathagata; Nath, S.; Pal, Santanu

    2015-03-01

    Background: Fusion between two massive nuclei is a very complex process and is characterized by three stages: (a) capture inside the potential barrier, (b) formation of an equilibrated compound nucleus (CN), and (c) statistical decay of the CN leading to a cold evaporation residue (ER) or fission. The second stage is the least understood of the three and is the most crucial in predicting yield of superheavy elements (SHE) formed in complete fusion reactions. Purpose: A systematic study of average fusion probability, PCN> , is undertaken to obtain a better understanding of its dependence on various reaction parameters. The study may also help to clearly demarcate onset of non-CN fission (NCNF), which causes fusion probability, PCN, to deviate from unity. Method: ER excitation functions for 52 reactions leading to CN in the mass region 170-220, which are available in the literature, have been compared with statistical model (SM) calculations. Capture cross sections have been obtained from a coupled-channels code. In the SM, shell corrections in both the level density and the fission barrier have been included. PCN> for these reactions has been extracted by comparing experimental and theoretical ER excitation functions in the energy range ˜5 %-35% above the potential barrier, where known effects of nuclear structure are insignificant. Results: PCN> has been shown to vary with entrance channel mass asymmetry, η (or charge product, ZpZt ), as well as with fissility of the CN, χCN. No parameter has been found to be adequate as a single scaling variable to determine PCN> . Approximate boundaries have been obtained from where PCN> starts deviating from unity. Conclusions: This study quite clearly reveals the limits of applicability of the SM in interpreting experimental observables from fusion reactions involving two massive nuclei. Deviation of PCN> from unity marks the beginning of the domain of dynamical models of fusion. Availability of precise ER cross sections

  2. The restoration of Wigner’s SU(4)-symmetry in the superheavy nucleus and its correlation with the problem “island of stability”, or does the “island of stability” exist?

    Science.gov (United States)

    Nurmukhamedov, A. M.

    2016-08-01

    This paper reviews the history and stages of experimental verification of the hypothesis of Wigner’s spin-isospin SU(4)-symmetry restoration in the field of heavy atomic nuclei and its implications on hypothesis of the “island of stability”. Energies of α-decay of a number of α-chains of new superheavy nuclei were calculated based on Wigner’s mass formula without contribution of spin-orbit interaction that correspond to the restoration of Wigner’s spin-isospin symmetry. Calculated energies of the α-decay fit the experimental data better than other theoretical approaches. It is concluded that there is a need to continue theoretical research of the “island of stability” taking into account mechanisms of restoration of Wigner’s spin-isospin SU(4)-symmetry.

  3. Half-lives of $\\alpha$ decay from natural nuclides and from superheavy elements

    CERN Document Server

    Qian, Yibin

    2014-01-01

    Recently, experimental researches on the $\\alpha$ decay with long lifetime are one of hot topics in the contemporary nuclear physics [e.g. N. Kinoshita {\\sl et al.} (2012) and J. W. Beeman {\\sl et al.} (2012) ]. In this study, we have systematically investigated the extremely long-lived $\\alpha$-decaying nuclei within a generalized density-dependent cluster model involving the experimental nuclear charge radii. In detail, the important density distribution of daughter nuclei is deduced from the corresponding experimental charge radii, leading to an improved $\\alpha$-core potential in the quantum tunneling calculation of $\\alpha$-decay width. Besides the excellent agreement between theory and experiment, predictions on half-lives of possible candidates for natural $\\alpha$ emitters are made for future experimental detections. In addition, the recently confirmed $\\alpha$-decay chain from $^{294}$117 is well described, including the attractive long-lived $\\alpha$-decaying $^{270}$Db, i.e., a positive step toward...

  4. Constraining the equation of state of nuclear matter from competition of fusion and quasi-fission in the reactions leading to production of the superheavy elements

    CERN Document Server

    Veselsky, Martin; Ma, Yu-Gang; Souliotis, Georgios A

    2016-01-01

    The mechanism of fusion hindrance, an effect preventing the synthesis of superheavy elements in the reactions of cold and hot fusion, is investigated using the Boltzmann-Uehling-Uhlenbeck equation, where Coulomb interaction is introduced. A strong sensitivity is observed both to the modulus of incompressibility of symmetric nuclear matter, controlling the competition of surface tension and Coulomb repulsion, and to the stiffness of the density-dependence of symmetry energy, influencing the formation of the neck prior to scission. The experimental fusion probabilities were for the first time used to derive constraints on the nuclear equation of state. A strict constraint on the modulus of incompressibility of nuclear matter $K_0 = 240 - 260$ MeV is obtained while the stiff density-dependences of the symmetry energy ($\\gamma>1.$) are rejected.

  5. Actinide collisions for QED and superheavy elements with the time-dependent Hartree-Fock theory and the Balian-Vénéroni variational principle

    Science.gov (United States)

    Simenel, Cédric; Golabek, Cédric; Kedziora, David J.

    2011-10-01

    Collisions of actinide nuclei form, during very short times of few zs (10-21 s), the heaviest ensembles of interacting nucleons available on Earth. Such collisions are used to produce super-strong electric fields by the huge number of interacting protons to test spontaneous positron-electron pair emission (vacuum decay) predicted by the quantum electrodynamics (QED) theory. Multi-nucleon transfer in actinide collisions could also be used as an alternative way to fusion in order to produce neutron-rich heavy and superheavy elements thanks to inverse quasifission mechanisms. Actinide collisions are studied in a dynamical quantum microscopic approach. The three-dimensional time-dependent Hartree-Fock (TDHF) code tdhf3d is used with a full Skyrme energy density functional to investigate the time evolution of expectation values of one-body operators, such as fragment position and particle number. This code is also used to compute the dispersion of the particle numbers (e.g., widths of fragment mass and charge distributions) from TDHF transfer probabilities, on the one hand, and using the BalianVeneroni variational principle, on the other hand. A first application to test QED is discussed. Collision times in 238U+238U are computed to determine the optimum energy for the observation of the vacuum decay. It is shown that the initial orientation strongly affects the collision times and reaction mechanism. The highest collision times predicted by TDHF in this reaction are of the order of ~ 4 zs at a center of mass energy of 1200 MeV. According to modern calculations based on the Dirac equation, the collision times at Ecm > 1 GeV are sufficient to allow spontaneous electron-positron pair emission from QED vacuum decay, in case of bare uranium ion collision. A second application of actinide collisions to produce neutron-rich transfermiums is discussed. A new inverse quasifission mechanism associated to a specific orientation of the nuclei is proposed to produce transfermium

  6. Electric dipole moments of superheavy elements: A case study on copernicium

    Science.gov (United States)

    RadžiÅ«tÄ--, Laima; Gaigalas, Gediminas; Jönsson, Per; Bieroń, Jacek

    2016-06-01

    The multiconfiguration Dirac-Hartree-Fock method was employed to calculate the atomic electric dipole moments (EDMs) of the superheavy element copernicium (Cn, Z =112 ). The EDM enhancement factors of Cn, calculated here, are about one order of magnitude larger than those of Hg. The exponential dependence of the enhancement factors on the atomic number Z along group 12 of the periodic table was derived from the EDMs of the entire homologous series, Zn, Cd, Hg, Cn, and Uhb. These results show that superheavy elements with sufficiently long half-lives are potential candidates for EDM searches.

  7. Electron structure of superheavy elements Uut, Fl and Uup ($Z$=113 to 115)

    CERN Document Server

    Dzuba, V A

    2016-01-01

    We use recently developed method of accurate atomic calculations which combines linearized single-double coupled cluster method with the configuration interaction technique to calculate ionisation potentials, excitation energies, static polarizabilities and valence electron densities for superheavy elements Uut, Fl and Uup ($Z$=113 to 115) and their ions. The accuracy of the calculations is controlled by comparing similar calculations for lighter analogs of the superheavy elements, Tl, Pb and Bi with experiment. The role of relativistic effects and correlations is discussed and comparison with earlier calculations is presented.

  8. Branching Ratios of a Decay for Nuclei near Deformed Shell Closures

    Institute of Scientific and Technical Information of China (English)

    WANG Yan-Zhao; ZHANG Hong-Fei; DONG Jian-Min; SU Xin-Ning; ZUO Wei; LI Jun-Qing

    2009-01-01

    The generalized liquid drop model (GLDM) is extended to the region around deformed shell closure 270Hs by taking into account the excitation energy EI+ of the residual daughter nucleus and the centrifugal potential energy Vcen(r).The branching ratios of a decays from the ground state of a parent nucleus to the ground state 0+ of its deformed daughter nucleus and to the first excited state 2+ are calculated in the framework of the GLDM.The results support the proposal that a measurement of α spectroscopy is a feasible method to extract information on nuclear deformation of superheavy nuclei around the deformed nucleus 270 Hs.

  9. Skyrme mean-field studies of nuclei far from the stability line

    CERN Document Server

    Heenen, P H; Cwiok, S; Nazarewicz, W; Valor, A

    1999-01-01

    Two applications of mean-field calculations based on 3D coordinate-space techniques are presented. The first concerns the structure of odd-N superheavy elements that have been recently observed experimentally and shows the ability of the method to describe, in a self-consistent way, very heavy odd-mass nuclei. Our results are consistent with the experimental data. The second application concerns the introduction of correlations beyond a mean-field approach by means of projection techniques and configuration mixing. Results for Mg isotopes demonstrate that the restoration of rotational symmetry plays a crucial role in the description of 32Mg.

  10. Observing atomic collapse resonances in artificial nuclei on graphene.

    Science.gov (United States)

    Wang, Yang; Wong, Dillon; Shytov, Andrey V; Brar, Victor W; Choi, Sangkook; Wu, Qiong; Tsai, Hsin-Zon; Regan, William; Zettl, Alex; Kawakami, Roland K; Louie, Steven G; Levitov, Leonid S; Crommie, Michael F

    2013-05-10

    Relativistic quantum mechanics predicts that when the charge of a superheavy atomic nucleus surpasses a certain threshold, the resulting strong Coulomb field causes an unusual atomic collapse state; this state exhibits an electron wave function component that falls toward the nucleus, as well as a positron component that escapes to infinity. In graphene, where charge carriers behave as massless relativistic particles, it has been predicted that highly charged impurities should exhibit resonances corresponding to these atomic collapse states. We have observed the formation of such resonances around artificial nuclei (clusters of charged calcium dimers) fabricated on gated graphene devices via atomic manipulation with a scanning tunneling microscope. The energy and spatial dependence of the atomic collapse state measured with scanning tunneling microscopy revealed unexpected behavior when occupied by electrons.

  11. Nuclear spectroscopy in nuclei with Z ≥ 110

    Energy Technology Data Exchange (ETDEWEB)

    Ackermann, D., E-mail: D.Ackermann@gsi.de

    2015-12-15

    The nuclear structure of species at the extreme of highest atomic numbers Z and nuclear masses A promises to reveal intriguing new features of this exotic hadronic matter. Their stability itself they owe to quantum-mechanic effects only. They form metastable states which, governed by the subtle interplay of α decay and spontaneous fission versus quantum-mechanic stabilization via shell effects, are in some cases more robust against disintegration than their ground states. Following the isotopic and isotonic trends of single particle levels, as well as collective features like deformation, may reveal the path towards the gap in the level densities, expected for the next closed proton and neutron shells at the so-called “island of stability” of spherical superheavy nuclei. Their atomic configuration offers via X-ray spectroscopy a tool to identify the atomic number of heavy species, where other more traditional methods like evaporation residue (ER)–α correlation are not applicable.

  12. Hot Money, Hot Potato

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    International hot money flowing into Chinese capital markets has caught the attention of Chinese watchdogs The Chinese are not the only ones feasting on the thriving property and stock markets. Apparently, these markets are the targets of international h

  13. 新核素~(263)Hs,~(260)Bh及其α衰变链上核素的半衰期%Half-lives of the newly synthesized nuclei in ~(263)Hs and ~(260)Bh α-decay chains

    Institute of Scientific and Technical Information of China (English)

    苏昕宁; 张鸿飞; 左维; 李君清

    2009-01-01

    The tunneling probability of potential barrier of the newly synthesized superheavy nuclei starting from ~(263)Hs and ~(260)Bh was calculated with the Generalized Liquid Drop Model (GLDM) connected with WKB approximation and their half-lives studied. The calculated results that are in agreement with the experimental data show that the α-decay half-lives of superheavy nuclei with the Generalized Liquid Drop Model connecting with WKB approximation can be successfully, applied in the study of superheavy nuclei and describe the α-decay of superheavy nuclei. The results also indicate that the syntheses of new nuclei ~(260)Bh and ~(263)Hs and the measurements of their α-decay half-lives are reliable.%运用推广的液滴模型(GLDM)并结合量子力学中的WKB方法计算了新核素~(263)Hs,~(260)Bh及其α衰变链上各核素的势垒贯穿概率,对该链上各原子核的α衰变半衰期进行了研究.计算结果表明:利用推广的液滴模型结合WKB方法计算出的α衰变半衰期可以很好地符合在超重核区的实验值,验证了推广的液滴模型在超重核区的适用性,能够很好地描述超重核的α衰变.同时,计算表明新核素~(260)Bh和~(263)Hs的合成及其半衰期的测量是可靠的.

  14. A Proposed Reaction Channel for the Synthesis of the Superheavy Nucleus Z=109

    Institute of Scientific and Technical Information of China (English)

    WANG Kun; MA Yu-Gang; MA Guo-Liang; WEI Yi-Bin; CAI Xiang-Zhou; CHEN Jin-Gen; GUO Wei; ZHONG Chen; SHEN Wen-Qing

    2004-01-01

    @@ We apply a statistical-evaporation model (HIVAP) to calculate the cross sections of superheavy elements, mainly about actinide targets and compare with some available experimental data. A reaction channel 30Si + 243Am is proposed for the synthesis of the element Z = 109 and the cross section is estimated.

  15. Average charge states of heavy and superheavy ions passing through a rarified gas : Theory and experiment

    NARCIS (Netherlands)

    Khuyagbaatar, J.; Shevelko, V. P.; Borschevsky, A.; Duellmann, Ch. E.; Tolstikhina, I. Yu.; Yakushev, A.

    2013-01-01

    The average charge states (q) over bar of heavy and superheavy ions (atomic numbers Z = 80-114) passing through He gas are studied experimentally and theoretically. Experimental data were measured at the gas-filled recoil separator, i.e., the TransActinide Separator and Chemistry Apparatus (TASCA) a

  16. Fission properties for r-process nuclei

    CERN Document Server

    Erler, J; Loens, H P; Martínez-Pinedo, G; Reinhard, P -G

    2011-01-01

    We present a systematics of fission barriers and fission lifetimes for the whole landscape of super-heavy elements (SHE), i.e. nuclei with Z>100. The fission lifetimes are also compared with the alpha-decay half-lives. The survey is based on a self-consistent description in terms of the Skyrme-Hartree-Fock (SHF) approach. Results for various different SHF parameterizations are compared to explore the robustness of the predictions. The fission path is computed by quadrupole constrained SHF. The computation of fission lifetimes takes care of the crucial ingredients of the large-amplitude collective dynamics along the fission path, as self-consistent collective mass and proper quantum corrections. We discuss the different topologies of fission landscapes which occur in the realm of SHE (symmetric versus asymmetric fission, regions of triaxial fission, bi-modal fission, and the impact of asymmetric ground states). The explored region is extended deep into the regime of very neutron-rich isotopes as they are expec...

  17. Properties and decay modes of hot nuclei produced in the reaction: {sup 36}Ar on {sup 58}Ni and detected with INDRA device; Proprietes et modes de desexcitation des noyaux chauds observes dans la reaction {sup 36}Ar sur {sup 58}Ni avec le detecteur INDRA

    Energy Technology Data Exchange (ETDEWEB)

    Nalpas, L. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. d`Astrophysique, de la Physique des Particules, de la Physique Nucleaire et de l`Instrumentation Associee]|[Paris-11 Univ., 91 - Orsay (France)

    1997-01-01

    Hot nuclei are formed in heavy ion collisions covering the Fermi energy domain. According to the excitation energy deposited into these nuclei, several de-excitation processes can be observed, in particular the emission of complex fragments (Z {>=} 3) which remains poorly understood. The GANIL facility offers the possibility to cover the excitation function for the Ar on Ni reaction over a broad energy range from 32 to 95 MeV/u where the hot nuclei evolve from classical `evaporation` to complete `vaporization` into light particles (neutrons, isotopes of H, He). The study of reaction mechanisms shows that from peripheral to central collisions the total cross section is dominated by binary dissipative collisions. Both partners coming from well-characterized events with the INDRA detector are reconstructed using the `Minimum Spanning Tree` method. Thus excitation energy up to 20 MeV/A are reached in the most violent collisions at the highest bombarding energy. The deposited energy is not shared in the mass ratio between the quasi-projectile and the quasi-target, the quasi-projectile being hotter. For total excitation energies ranging roughly from 2 to 8 MeV/A, the proportion of `multifragmentation` events increases to reach a plateau at about 10 MeV/A due to the rising probability to have complete `vaporization` of the system above 8 MeV/A. The steady increase of the temperature extracted from the double isotopic He-Li ratios with excitation energy for the quasi-projectile suggests a progressive evolution of the de-excitation processes as predicted by statistical models. No signal of first order liquid-gas phase transition is seen in our data. (author) 124 refs.

  18. Charge composition of the VVH cosmic ray nuclei in the energy range of 1-2 GeV/nucleon: The results of the track investigation in olivine from the Marjalahti pallasite

    Energy Technology Data Exchange (ETDEWEB)

    Bagulya, A.V.; Goncharova, L.A. [Lebedev Physical Institute, Russian Academy of Sciences, Leninskii pr., 53, Moscow, 119991 (Russian Federation); Ivliev, A.I.; Kalinina, G.V.; Kashkarov, L.L., E-mail: cosmo@geokhi.r [Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, Kosygina str., 19, 119991 (Russian Federation); Konovalova, N.S.; Okat' eva, N.M. [Lebedev Physical Institute, Russian Academy of Sciences, Leninskii pr., 53, Moscow, 119991 (Russian Federation); Polukhina, N.G., E-mail: poluhina@sci.lebedev.r [Lebedev Physical Institute, Russian Academy of Sciences, Leninskii pr., 53, Moscow, 119991 (Russian Federation); Roussetski, A.S.; Starkov, N.I.; Tsarev, V.A. [Lebedev Physical Institute, Russian Academy of Sciences, Leninskii pr., 53, Moscow, 119991 (Russian Federation); Vladymyrov, M.S., E-mail: neworld@itep.r [Lebedev Physical Institute, Russian Academy of Sciences, Leninskii pr., 53, Moscow, 119991 (Russian Federation)

    2009-10-15

    New results of the measurements performed in the 'OLIMPIA' project framework of the relative abundance of superheavy (Z >= 50) nuclei in galactic cosmic rays are presented. The method of detection and analysis of nucleus tracks in olivine crystals from the Marjalahti pallasite was based on the combination of the multistage etching of individual crystals and measurement of the track parameters (etchable length and corresponding track-etching rate) on the completely automated PAVICOM setup.

  19. In search of a broader microscopic underpinning of the potential energy surface in heavy deformed nuclei

    Science.gov (United States)

    Hess, P. O.; Ermamatov, M.

    2017-07-01

    Starting from the content of the shell model space and using a simple symplectic as a weight Hamiltonian, the relative positions of different symplectic irreducible representations are deduced. Applying a geometrical mapping leads to a microscopically derived Potential-Energy-Surface. After smoothing this surface and fitting a mass parameter to the first excited 6+-state in the ground state band, the spectrum of a nucleus can be reproduced qualitatively. The method is also used to obtain a first estimation of the quadrupole Potential Energy Surface of any nucleus, allowing to obtain information about the structure of the nucleus in question. Of special interest is the prediction of the structure of nuclei away from the valley of stability and of super-heavy nuclei. The method will be illustrated at184W. One objective is to show that the Pauli Exclusion Principle is the main driving force for the structure of a nucleus, though some further microscopic input has to be used.

  20. Fifth International Conference on Fission and Properties of Neutron-Rich Nuclei

    CERN Document Server

    Ramayya, A V; ICFN5

    2014-01-01

    These proceedings are the fifth in the series of International Conferences covering fission and properties of neutron-rich nuclei, which are at the forefront of nuclear research. The time interval of 5 years between each conference allows for significant new results to be achieved. Recently, world leaders in theory and experiments in research and the development of new facilities for research presented their latest results in areas such as synthesis of superheavy elements, new facilities for and recent results with radioactive ion beams, structure of neutron-rich nuclei, nuclear fission process, fission yields and nuclear astrophysics. This book is a major source of the latest research in these areas and plans for the future. The conference brought together a unique group of over 100 speakers including leaders from the major nuclear laboratories in Canada, China, France, Finland, Germany, Italy, Japan, Russia, Switerzland and the US along with leading research scientists from around the world.

  1. Superheavy-element spectroscopy: Correlations along element 115 decay chains

    Directory of Open Access Journals (Sweden)

    Rudolph D.

    2016-01-01

    Full Text Available Following a brief summary of the region of the heaviest atomic nuclei yet created in the laboratory, data on more than hundred α-decay chains associated with the production of element 115 are combined to investigate time and energy correlations along the observed decay chains. Several of these are analysed using a new method for statistical assessments of lifetimes in sets of decay chains.

  2. Super- and Hyperdeformed Isomeric States and Long-Lived Superheavy Elements

    CERN Document Server

    Marinov, A; Kolb, D; Brandt, R; Gentry, R V; Pape, A

    2004-01-01

    The recent discoveries of the long-lived high spin super- and hyperdeformed isomeric states and their unusual radioactive decay properties are described. Based on their existence a consistent interpretation is given to the production of the long-lived superheavy element with Z = 112, via secondary reactions in CERN W targets, and to the low energy and very enhanced alpha-particle groups seen in various actinide fractions separated from the same W target. In addition, consistent interpretations are suggested for previously unexplained phenomena seen in nature. These are the Po halos, the low-energy enhanced 4.5 MeV alpha-particle group proposed to be due to an isotope of a superheavy element with Z = 108, and the giant halos.

  3. New Superheavy Element Isotopes: 242Pu(48Ca,5n)285114

    Energy Technology Data Exchange (ETDEWEB)

    Ellison, Paul A; Gregorich, Kenneth E.; Berryman, Jill S.; Bleuel, Darren L.; Clark, Roderick M.; Dragojevic, Irena; Dvorak, Jan; Fallon, Paul; Fineman-Sotomayor, Carolina; Gates, Jacklyn M.; Gothe, Oliver R.; Lee, I-Yang; Loveland, Walter D.; McLaughlin, Joseph P.; Paschalis, Stefanos; Petri, Marina-Kalliopi; Qian, Jing; Stavsetra, Liv; Wiedeking, Mathis; Nitsche, Heino

    2010-10-22

    The new, neutron-deficient, superheavy element isotope {sup 285}114 was produced in {sup 48}Ca irradiations of {sup 242}Pu targets at a center-of-target beam energy of 256 MeV (E* = 50 MeV). The {alpha} decay of {sup 285}114 was followed by the sequential {alpha} decay of four daughter nuclides, {sup 281}Cn, {sup 277}Ds, {sup 273}Hs, and {sup 269}Sg. {sup 265}Rf was observed to decay by spontaneous fission. The measured {alpha}-decay Q values were compared with those from a macroscopic-microscopic nuclear mass model to give insight into superheavy element shell effects. The {sup 242}Pu({sup 48}Ca,5n){sup 285}114 cross section was 0.6{sub -0.5}{sup +0.9} pb.

  4. Superheavy dark matter and IceCube neutrino signals:bounds on decaying dark matter

    CERN Document Server

    Rott, Carsten; Park, Seong Chan

    2014-01-01

    Superheavy dark matter may show its presence in high energy neutrino signals detected on earth. From the latest results of IceCube, we could set the strongest lower bound on the lifetime of dark matter beyond 100 TeV around $10^{28} {\\rm sec}$. The excess around a PeV is noticed and may be interpreted as the first signal of DM even though further confirmation and dedicated searches are invited.

  5. Superheavy Element Studies with TASCA at GSI: Spectroscopy of Element 115 Decay Chains

    Science.gov (United States)

    Rudolph, Dirk

    Experimental campaigns on investigations of the superheavy elements 115, 117, 119, and 120 were conducted 2011 and 2012 at the gas-filled "TransActinide Separator and Chemistry Apparatus" (TASCA) at the GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany. Nuclear structure implications of first-ever α-photon coincidence spectroscopy on element 115 and its daughters obtained with the TASISpec set-up are discussed, likewise possible connections between decay chains associated with elements 115 and 117.

  6. Superheavy Element Studies with TASCA at GSI: Spectroscopy of Element 115 Decay Chains

    OpenAIRE

    Rudolph, Dirk

    2015-01-01

    Experimental campaigns on investigations of the superheavy elements 115, 117, 119, and 120 were conducted 2011 and 2012 at the gas-filled “TransActinide Separator and Chemistry Apparatus” (TASCA) at the GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany. Nuclear structure implications of first-ever α-photon coincidence spectroscopy on element 115 and its daughters obtained with the TASISpec set-up are discussed, likewise possible connections between decay chains associated with...

  7. Super-heavy dark matter – Towards predictive scenarios from inflation

    Energy Technology Data Exchange (ETDEWEB)

    Kannike, Kristjan [National Institute of Chemical Physics and Biophysics, Rävala 10, 10143 Tallinn (Estonia); Racioppi, Antonio, E-mail: antonio.racioppi@kbfi.ee [National Institute of Chemical Physics and Biophysics, Rävala 10, 10143 Tallinn (Estonia); Raidal, Martti [National Institute of Chemical Physics and Biophysics, Rävala 10, 10143 Tallinn (Estonia); Institute of Physics, University of Tartu, W. Ostwaldi 1, 50411 Tartu (Estonia)

    2017-05-15

    A generic prediction of the Coleman–Weinberg inflation is the existence of a heavy particle sector whose interactions with the inflaton, the lightest state in this sector, generate the inflaton potential at loop level. For typical interactions the heavy sector may contain stable states whose relic abundance is generated at the end of inflation by the gravity alone. This general feature, and the absence of any particle physics signal of dark matter so far, motivates us to look for new directions in the dark sector physics, including scenarios in which dark matter is super-heavy. In this article we study the possibility that the dark matter is even heavier than the inflaton, its existence follows from the inflaton dynamics, and its abundance today is naturally determined by the weakness of gravitational interaction. This implies that the super-heavy dark matter scenarios can be tested via the measurements of inflationary parameters and/or the CMB isocurvature perturbations and non-Gaussianities. We explicitly work out details of three Coleman–Weinberg inflation scenarios, study the systematics of super-heavy dark matter production in those cases, and compute which parts of the parameter spaces can be probed by the future CMB measurements.

  8. From super-charged nuclei to massive nuclear density cores

    CERN Document Server

    Popov, Vladimir

    2010-01-01

    Due to $e^+e^-$-pair production in the field of supercritical $(Z \\gg Z_{cr}\\approx 170 $) nucleus an electron shell, created out of the vacuum, is formed. The distribution of the vacuum charge in this shell has been determined for super-charged nuclei $Ze^3 \\ga 1$ within the framework of the Thomas-Fermi equation generalized to the relativistic case. For $Ze^3 \\gg 1$ the electron shell penetrates inside the nucleus and almost completely screens its charge. Inside such nucleus the potential takes a constant value equal to $V_0=-(3\\pi^2 n_p)^{1/3} \\sim -2m_{\\pi}c^2$, and super-charged nucleus represents an electrically neutral plasma consisting of $e,p$ and $n$. Near the edge of the nucleus a transition layer exists with a width $\\lambda \\approx \\alpha^{-1/2} \\hbar/m_{\\pi} c\\sim 15$ fm, which is independent of $Z~~ (\\hbar/m_{\\pi} c \\ll \\lambda \\ll \\hbar/m_e c)$. The electric field and surface charge are concentrated in this layer. These results, obtained earlier for hypothetical superheavy nuclei with $Z \\sim ...

  9. Hot microswimmers

    Science.gov (United States)

    Kroy, Klaus; Chakraborty, Dipanjan; Cichos, Frank

    2016-11-01

    Hot microswimmers are self-propelled Brownian particles that exploit local heating for their directed self-thermophoretic motion. We provide a pedagogical overview of the key physical mechanisms underlying this promising new technology. It covers the hydrodynamics of swimming, thermophoresis and -osmosis, hot Brownian motion, force-free steering, and dedicated experimental and simulation tools to analyze hot Brownian swimmers.

  10. Actinide collisions for QED and superheavy elements with the time-dependent Hartree-Fock theory and the Balian-V\\'en\\'eroni variational principle

    CERN Document Server

    Simenel, Cédric; Kedziora, David J

    2011-01-01

    Collisions of actinide nuclei form, during very short times of few zs ($10^{-21}$ s), the heaviest ensembles of interacting nucleons available on Earth. Such collisions are used to produce super-strong electric fields by the huge number of interacting protons to test spontaneous positron-electron pair emission (vacuum decay) predicted by the quantum electrodynamics (QED) theory. Multi-nucleon transfer in actinide collisions could also be used as an alternative way to fusion in order to produce neutron-rich heavy and superheavy elements thanks to inverse quasifission mechanisms. Actinide collisions are studied in a dynamical quantum microscopic approach. The three-dimensional time-dependent Hartree-Fock (TDHF) code {\\textsc{tdhf3d}} is used with a full Skyrme energy density functional to investigate the time evolution of expectation values of one-body operators, such as fragment position and particle number. This code is also used to compute the dispersion of the particle numbers (e.g., widths of fragment mass...

  11. Nuclear fragmentation for Xe+Au and Xe+Ag systems at an energy of 44 A.MeV, formation and decay of hot nuclei; Etude de la fragmentation nucleaire pour les systemes XE+AU et XE+AG a 44 A.MeV, production et decroissance de noyaux chauds

    Energy Technology Data Exchange (ETDEWEB)

    Meslin, C.

    1995-01-01

    A study of the formation and the decay of hot nuclear fragments produced in the reactions Xe+Au and Xe+Ag at an energy of 44 A.MeV is presented in this thesis. The 4{pi} experimental setup consisted of four multidetectors -two for the detection of the fragments (Z>7; DELF and XYZT) and two for the detection of the charged particles (Z<6; MUR and TONNEAU) and allowed an analysis using ``complete events`` (80 % of the total charge and the total parallel linear momentum of the entrance channel) to be carried out. The reaction mechanism is binary with as observed at low energy an almost complete relaxation of the incident energy. The collision results in two hot fragments at the beginning of the exit channel which decay by evaporation and/or fragmentation. In addition of these two body events, we have identified a new dynamic mechanism where we detect a small fragment, called the neck, coming form the overlap of the nuclei during the interaction, in coincidence with a projectile-like fragment and a target-like fragment. For the most dissipative collisions, the deep inelastic collision have allowed an estimation of the lifetime of the hot nuclear fragments to be made. This is possible using proximity effects and fragment-fragment space-time correlations of the decay of one or two primary partners from the deep inelastic collisions. This method is seen to reach its limits in the case of the reactions studied here. (authors). 61 refs.

  12. Fission and Properties of Neutron-Rich Nuclei

    Science.gov (United States)

    Hamilton, Joseph H.; Ramayya, A. V.; Carter, H. K.

    2008-08-01

    . Fission-fragment spectroscopy with STEFF / A. G. Smith ... [et al.]. Gamma ray multiplicity of [symbol]Cf spontaneous fission using LiBerACE / D. L. Bleuel ... [et al.]. Excitation energy dependence of fragment mass and total kinetic energy distributions in proton-induced fission of light actinides / I. Nishinaka ... [et al.]. A dynamical calculation of multi-modal nuclear fission / T. Wada and T. Asano. Structure of fission potential energy surfaces in ten-dimensional spaces / V. V. Pashkevich, Y. K Pyatkov and A. V. Unzhakova. A possible enhancement of nuclear fission in scattering with low energy charged particles / V. Gudkov. Dynamical multi-break processes in the [symbol]Sn + [symbol]Ni system at 35 MeV/Nucleon / M. Papa and ISOSPIN-RE VERSE collaboration -- New experimental techniques. MTOF - a high resolution isobar separator for studies of exotic decays / A. Piechaczek ... [et al.]. Development of ORRUBA: a silicon array for the measurement of transfer reactions in inverse kinematics / S. D. Pain ... [et al.]. Indian national gamma array: present & future / R. K. Bhowmik. Absolute intensities of [symbol] rays emitted in the decay of [symbol]U / H. C. Griffin -- Superheavy elements theory and experiments / M. G. Itkis ... [et al.]. Study of superheavy elements at SHIP / S. Hofinann. Heaviest nuclei from [symbol]Ca-induced reactions / Yu. Ts. Oaanessian. Superheavy nuclei and giant nuclear systems / W. Greiner and V. Zagrebaev. Fission approach to alpha-decay of superheavy nuclei / D.N. Poenaru and W. Greiner. Superheavy elements in the Magic Islands / C. Samanta. Relativistic mean field studies of superheavy nuclei / A. V. Afanas jev. Understanding the synthesis of the heaviest nuclei / W. Loveland -- Mass measurements and g-factors. G factor measurements in neutron-rich [symbol]Cf fission fragments, measured using the gammasphere array / R. Orlandi ... [et al.]. Technique for measuring angular correlations and g-factors in neutron rich nuclei produced by the

  13. Actinide collisions for QED and superheavy elements with the time-dependent Hartree-Fock theory and the Balian-Vénéroni variational principle

    Directory of Open Access Journals (Sweden)

    Kedziora David J.

    2011-10-01

    Full Text Available Collisions of actinide nuclei form, during very short times of few zs (10−21 s, the heaviest ensembles of interacting nucleons available on Earth. Such collisions are used to produce super-strong electric fields by the huge number of interacting protons to test spontaneous positron-electron pair emission (vacuum decay predicted by the quantum electrodynamics (QED theory. Multi-nucleon transfer in actinide collisions could also be used as an alternative way to fusion in order to produce neutron-rich heavy and superheavy elements thanks to inverse quasifission mechanisms. Actinide collisions are studied in a dynamical quantum microscopic approach. The three-dimensional time-dependent Hartree-Fock (TDHF code tdhf3d is used with a full Skyrme energy density functional to investigate the time evolution of expectation values of one-body operators, such as fragment position and particle number. This code is also used to compute the dispersion of the particle numbers (e.g., widths of fragment mass and charge distributions from TDHF transfer probabilities, on the one hand, and using the BalianVeneroni variational principle, on the other hand. A first application to test QED is discussed. Collision times in 238U+238U are computed to determine the optimum energy for the observation of the vacuum decay. It is shown that the initial orientation strongly affects the collision times and reaction mechanism. The highest collision times predicted by TDHF in this reaction are of the order of ~ 4 zs at a center of mass energy of 1200 MeV. According to modern calculations based on the Dirac equation, the collision times at Ecm > 1 GeV are sufficient to allow spontaneous electron-positron pair emission from QED vacuum decay, in case of bare uranium ion collision. A second application of actinide collisions to produce neutron-rich transfermiums is discussed. A new inverse quasifission mechanism associated to a specific orientation of the nuclei is proposed to

  14. HOT 2012

    DEFF Research Database (Denmark)

    Lund, Henriette Romme

    Undersøgelse af, hvad der er hot - og hvad der burde være hot på læseområdet med 21 læsekyndige. Undersøgelsen er gennemført siden 2010. HOT-undersøgelsen er foretaget af Nationalt Videncenter for Læsning - Professionshøjskolerne i samarb. med Dansklærerforeningen...

  15. All-order calculations of the spectra of superheavy elements E113 and E114

    CERN Document Server

    Dinh, T H

    2016-01-01

    We apply a recently developed method (V. A. Dzuba, PRA 90, 012517 (2014); J. S. M. Ginges and V. A. Dzuba, PRA 91, 042505 (2015)) to calculate energy levels of superheavy elements Uut (Z = 113), Fl (Z = 114), and Fl+. The method combines the linearized single-double coupledcluster technigue, the all-order correlation potential method and configuration interaction method. Breit and quantum electrodynamic corrections are included. The role of relativistic and correlation effects is discussed. Similar calculations for Tl, Pb and Pb+ are used to gauge the accuracy of the calculations.

  16. Ionization potentials and polarizabilities of superheavy elements from Db to Cn ($Z$=105 to 112)

    CERN Document Server

    Dzuba, V A

    2016-01-01

    Relativistic Hartree-Fock and random phase approximation methods for open shells are used to calculate ionization potentials and static scalar polarizabilities of eight superheavy elements with open $6d$-shell, which include Db, Sg, Bh, Hs, Mt, Ds, Rg and Cn ($Z$=105 to 112). Inter-electron correlations are taken into account with the use of the semi-empirical polarization potential. Its parameters are chosen to fit the known ionization potentials of lighter atoms. Calculations for lighter atoms are also used to illustrate the accuracy of the approach.

  17. Exciting interdisciplinary physics quarks and gluons, atomic nuclei, relativity and cosmology, biological systems

    CERN Document Server

    2013-01-01

    Nuclear physics is an exciting, broadly faceted field. It spans a wide range of topics, reaching from nuclear structure physics to high-energy physics, astrophysics and medical physics (heavy ion tumor therapy).  New developments are presented in this volume and the status of research is reviewed. A major focus is put on nuclear structure physics, dealing with superheavy elements and with various forms of exotic nuclei: strange nuclei, very neutron rich nuclei, nuclei of antimatter. Also quantum electrodynamics of strong fields is addressed, which is linked to the occurrence of giant nuclear systems in, e.g., U+U collisions. At high energies nuclear physics joins with elementary particle physics. Various chapters address the theory of elementary matter at high densities and temperature, in particular the quark gluon plasma which is predicted by quantum chromodynamics (QCD) to occur in high-energy heavy ion collisions. In the field of nuclear astrophysics, the properties of neutron stars and quark stars are d...

  18. Jet Evolution in Hot and Cold QCD Matter

    OpenAIRE

    Domdey, Svend Oliver

    2010-01-01

    In this thesis, we study the evolution of energetic partons in hot and cold QCD matter. In both cases, interactions with the medium lead to energy loss of the parton and its transverse momentum broadens. The propagation of partons in cold nuclear matter can be investigated experimentally in deep-inelastic scattering (DIS) on nuclei. We use the dipole model to calculate transverse momentum broadening in DIS on nuclei and compare to experimental data from HERMES. In hot matter, the evolution of...

  19. Quarks in finite nuclei

    CERN Document Server

    Guichon, P A M; Thomas, A W

    1996-01-01

    We describe the development of a theoretical description of the structure of finite nuclei based on a relativistic quark model of the structure of the bound nucleons which interact through the (self-consistent) exchange of scalar and vector mesons.

  20. Calculation of α preformation for nuclei near N=162 and N=184

    Science.gov (United States)

    Zhang, G. L.; Le, X. Y.; Zhang, H. Q.

    2009-12-01

    The α preformation factor and the penetration probability are carefully analyzed for heavy and superheavy even-even nuclei. The penetration probability of an α cluster in the parent nucleus is calculated within the WKB approximation, whereas the nuclear potential between an α cluster and the daughter nucleus is obtained in the frame of a double-folding model with a density-dependent nucleon-nucleon interaction, in which the zero-range exchange term is supplemented. The α preformation factors in different shell regions are compared. It is shown that shell effects play an important role in α preformation. The preformation factor can supply information on the nuclear structure, and the penetration probability mainly determines the α-decay half-life. The results indicate that the deformed-subshell region at N=162 is different from that at N=152, and Z=114 and N=184 may lie in the closed-shell region.

  1. Neutrino masses and superheavy dark matter in the 3-3-1-1 model

    CERN Document Server

    Huong, D T

    2016-01-01

    In this work, we interpret the 3-3-1-1 model when the B-L and 3-3-1 breaking scales behave simultaneously as the grand unification scale. This setup not only realizes the previously-achieved consequences of inflation and leptogenesis, but also provides new insights in superheavy dark matter and neutrino masses. We argue that the 3-3-1-1 model can incorporate a scalar sextet, which induces both small masses for the neutrinos via a combined type I and II seesaw and large masses for the neutral fermions. All the new particles have the masses in the grand unification scale. The lightest particle among the W-particles that have wrong B-L number may be a superheavy dark matter as it is stabilized by the W-parity. The candidate may be a Majorana fermion, a neutral scalar, or a neutral gauge boson, which was properly created in the early universe due to gravitational effects on the vacuum or thermal production after cosmic inflation.

  2. Neutrino masses and superheavy dark matter in the 3-3-1-1 model

    Energy Technology Data Exchange (ETDEWEB)

    Huong, D.T.; Dong, P.V. [Vietnam Academy of Science and Technology, Institute of Physics, Hanoi (Viet Nam)

    2017-04-15

    In this work, we interpret the 3-3-1-1 model when the B - L and 3-3-1 breaking scales behave simultaneously as the inflation scale. This setup not only realizes the previously achieved consequences of inflation and leptogenesis, but also provides new insights in superheavy dark matter and neutrino masses. We argue that the 3-3-1-1 model can incorporate a scalar sextet, which induces both small masses for the neutrinos via a combined type I and II seesaw and large masses for the new neutral fermions. Additionally, all the new particles have large masses in the inflation scale. The lightest particle among the W-particles that have abnormal (i.e., wrong) B - L number in comparison to those of the standard model particles may be superheavy dark matter as it is stabilized by W-parity. The dark matter candidate may be a Majorana fermion, a neutral scalar, or a neutral gauge boson, which was properly created in the early universe due to gravitational effects on the vacuum or thermal production after cosmic inflation. (orig.)

  3. Synthesis of superheavy elements: Uncertainty analysis to improve the predictive power of reaction models

    Science.gov (United States)

    Lü, Hongliang; Boilley, David; Abe, Yasuhisa; Shen, Caiwan

    2016-09-01

    Background: Synthesis of superheavy elements is performed by heavy-ion fusion-evaporation reactions. However, fusion is known to be hindered with respect to what can be observed with lighter ions. Thus some delicate ambiguities remain on the fusion mechanism that eventually lead to severe discrepancies in the calculated formation probabilities coming from different fusion models. Purpose: In the present work, we propose a general framework based upon uncertainty analysis in the hope of constraining fusion models. Method: To quantify uncertainty associated with the formation probability, we propose to propagate uncertainties in data and parameters using the Monte Carlo method in combination with a cascade code called kewpie2, with the aim of determining the associated uncertainty, namely the 95 % confidence interval. We also investigate the impact of different models or options, which cannot be modeled by continuous probability distributions, on the final results. An illustrative example is presented in detail and then a systematic study is carried out for a selected set of cold-fusion reactions. Results: It is rigorously shown that, at the 95 % confidence level, the total uncertainty of the empirical formation probability appears comparable to the discrepancy between calculated values. Conclusions: The results obtained from the present study provide direct evidence for predictive limitations of the existing fusion-evaporation models. It is thus necessary to find other ways to assess such models for the purpose of establishing a more reliable reaction theory, which is expected to guide future experiments on the production of superheavy elements.

  4. Average charge states of heavy and superheavy ions passing through a rarified gas: Theory and experiment

    Science.gov (United States)

    Khuyagbaatar, J.; Shevelko, V. P.; Borschevsky, A.; Düllmann, Ch. E.; Tolstikhina, I. Yu.; Yakushev, A.

    2013-10-01

    The average charge states q¯ of heavy and superheavy ions (atomic numbers Z=80-114) passing through He gas are studied experimentally and theoretically. Experimental data were measured at the gas-filled recoil separator, i.e., the TransActinide Separator and Chemistry Apparatus (TASCA) at GSI Darmstadt, for ion energies of a few hundred keV/u at gas pressures of 0.2 to 2.0 mbar. An attempt is made to describe experimental q¯ values by means of atomic calculations of the binding energies and electron-loss and electron-capture cross sections. The influence of the gas-density effect is included in the calculations. The calculated q¯ reproduce the experimental values for elements with Z=80-114 within 20%. A comparison with different semiempirical models is presented as well, including a local fit of high accuracy, which is often used in superheavy-element experiments to estimate the average charge states of heavy ions, e.g., at the gas-filled recoil separator TASCA. The q¯ values for elements with Z=115, 117, 119, and 120 at He-gas pressure of 0.8 mbar are predicted.

  5. Formation and de-excitation of hot nuclei in reactions induced by proton beams (475 MeV and 2 GeV) and {sup 3}He beam (2 GeV); Formation et desexcitation des noyaux chauds dans les reactions induites par des faisceaux de protons (475 MeV et 2 GeV) et d`{sup 3}He(2 GeV)

    Energy Technology Data Exchange (ETDEWEB)

    Ledoux, X.

    1995-04-01

    We are studying the formation and the de-excitation of hot nuclei created in reactions induced by light high energy projectiles. These reactions, described in a two step model: an intranuclear cascade followed by an evaporation phase, produce nuclei in which the collective modes (compression, rotation, deformation) are weakly excited. By measuring the neutron multiplicities, event by event with ORION, and the light charged particle energies and multiplicities one can evaluate the excitation energy distribution of the nuclei. At the same time, theoretical simulations are carried out using the intranuclear cascade code developed by J. Cugnon and the statistical de-excitation code GEMINI. The good agreement with experimental results indicate that 10% of the p-nucleus interactions lead to temperatures greater than 5 MeV. The observation of the fission of a nucleus with a temperature close to 5 MeV shows that the nucleus behaves as a set of bound nucleons and, that the temperature stability limit is not yet reached. The observed decline of fission probability at high excitation energies is most likely to be correlated to the appearance of an other de-excitation process (evaporation residues emission or multifragmentation) which could not be experimentally detected. Finally, in the last chapter, we briefly present the principle of transmutation for long-lived nuclear waste with a proton accelerator and underline the interest of the present work in such studies. (author). 54 refs., 80 figs., 13 tabs.

  6. Mini-Proceedings of ECT Workshop "Strangeness in Nuclei"

    CERN Document Server

    Curceanu, C

    2011-01-01

    This workshop brought together international experts in the research area of strangeness in nuclei physics, working on theory as well as on experiments, to discuss the present status, to develop new methods of analysis and to have the opportunity for brainstorming towards future studies, going towards a deeper understanding of the hot topics in the low-energy QCD in the strangeness sector.

  7. Scattering Of Light Nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Quaglioni, S; Navratil, P; Roth, R

    2009-12-15

    The exact treatment of nuclei starting from the constituent nucleons and the fundamental interactions among them has been a long-standing goal in nuclear physics. Above all nuclear scattering and reactions, which require the solution of the many-body quantum-mechanical problem in the continuum, represent an extraordinary theoretical as well as computational challenge for ab initio approaches.We present a new ab initio many-body approach which derives from the combination of the ab initio no-core shell model with the resonating-group method [4]. By complementing a microscopic cluster technique with the use of realistic interactions, and a microscopic and consistent description of the nucleon clusters, this approach is capable of describing simultaneously both bound and scattering states in light nuclei. We will discuss applications to neutron and proton scattering on sand light p-shell nuclei using realistic nucleon-nucleon potentials, and outline the progress toward the treatment of more complex reactions.

  8. Pro duction of Exotic Nuclei in Low-Energy Multi-Nucleon Transfer Reactions

    Institute of Scientific and Technical Information of China (English)

    VI Zagrebaev; Walter Greiner

    2015-01-01

    Multinucleon transfer processes in low-energy heavy ion collisions open a new field of re-search in nuclear physics, namely, production and studying properties of heavy neutron rich nuclei. This not-yet-explored area of the nuclear map is extremely important for understanding the astrophysical nu-cleosynthesis and the origin of heavy elements. Beams of very heavy U-like ions are needed to produce new long-living isotopes of transfermium and superheavy elements located very close to the island of sta-bility. The calculated cross sections are high enough to perform the experiments at available accelerators. Beams of medium-mass ions (such as 136Xe, 192Os, 198Pt) can be used for the production of neutron rich nuclei located along the neutron closed shell N=126 (the last waiting point) having the largest impact on the astrophysical r-process. The Low-energy multinucleon transfer reactions is a very efficient tool also for the production and spectroscopic study of light exotic nuclei. The corresponding cross sections are 2 or 3 orders of magnitude larger as compared with high energy fragmentation reactions.

  9. Anharmonic vibrations in nuclei

    CERN Document Server

    Fallot, M; Andrés, M V; Catara, F; Lanza, E G; Scarpaci, J A; Chomaz, Ph.

    2003-01-01

    In this letter, we show that the non-linearitites of large amplitude motions in atomic nuclei induce giant quadrupole and monopole vibrations. As a consequence, the main source of anharmonicity is the coupling with configurations including one of these two giant resonances on top of any state. Two-phonon energies are often lowered by one or two MeV because of the large matrix elements with such three phonon configurations. These effects are studied in two nuclei, 40Ca and 208Pb.

  10. The shapes of nuclei

    CERN Document Server

    Bertsch, G F

    2016-01-01

    Gerry Brown initiated some early studies on the coexistence of different nuclear shapes. The subject has continued to be of interest and is crucial for understanding nuclear fission. We now have a very good picture of the potential energy surface with respect to shape degrees of freedom in heavy nuclei, but the dynamics remain problematic. In contrast, the early studies on light nuclei were quite successful in describing the mixing between shapes. Perhaps a new approach in the spirit of the old calculations could better elucidate the character of the fission dynamics and explain phenomena that current theory does not model well.

  11. A search for superheavy elements in meteorites using a neutron multiplicity detector

    Energy Technology Data Exchange (ETDEWEB)

    Barton, J.C. (Birkbeck Coll., London (United Kingdom)); Hatton, C.J. (Leeds Univ. (United Kingdom). Dept. of Combined Studies); McMillan, J.E. (Leeds Univ. (United Kingdom). Dept. of Physics)

    1991-12-01

    A search for superheavy element fission events in meteoritic samples was made using a novel neutron multiplicity detector which was operated underground. No differences could be detected between samples of meteoritic and terrestrial materials. All multiple neutron events could be attributed either to very small amounts of fissile material contaminating the detector materials or to the effects of cosmic rays. An upper limit of 1.3 kg{sup -1}y{sup -1} for the fission rate in meteorites is derived. Assuming the half life to be 10{sup 9}y, this translates to a concentration of <1.0 x 10{sup -15}kg kg{sup -1} which is below all previous measurements. (author).

  12. Elusive active galactic nuclei

    NARCIS (Netherlands)

    Maiolino, R; Comastri, A; Gilli, R; Nagar, NM; Bianchi, S; Boker, T; Colbert, E; Krabbe, A; Marconi, A; Matt, G; Salvati, M

    2003-01-01

    A fraction of active galactic nuclei do not show the classical Seyfert-type signatures in their optical spectra, i.e. they are optically 'elusive'. X-ray observations are an optimal tool to identify this class of objects. We combine new Chandra observations with archival X-ray data in order to obtai

  13. Validation of new superheavy elements and IUPAC-IUPAP joint working group

    Science.gov (United States)

    Jarlskog, Cecilia

    2016-12-01

    The great chemist Glenn Seaborg has written a delightful little book "Man-made Transuranium Elements", published in 1963, in which he points out that: "The former basic criterion for the discovery of a new element - namely, chemical identification and separation from all previously-known elements - had to be changed in the case of lawrencium (element 103). This also may be true for elements beyond lawrencium." Indeed this is what has happened. The elements with Z ≥ 103 are produced in nuclear reactions and are detected by counters. The detectors have undergone substantial refinement. For example one uses multiwire proportional chambers [for which George Charpak received the 1992 Nobel Prize in Physics] as well as solid state micro-strip detectors. In spite of this remarkable shift from chemistry to physics, the managerial staff of the International Union of Pure and Applied Chemistry (IUPAC) does not seem to be aware of what has been going on. The validation of superheavy elements should be done by physicists as the chemists lack the relevant competence as I will discuss here below. This article is about a collaboration between International Union of Pure and Applied Chemistry (IUPAC) and its sister organization International Union of Pure and Applied Physics (IUPAP), to deal with discovery of superheavy elements beyond Z = 112. I spent a great deal of time on this issue. In my opinion, the collaboration turned out to be a failure. For the sake of science, which should be our most important concern (and not politics), the rules for the future collaborations, if any, should be accurately defined and respected. The validation of new elements should be done by people who have the relevant competence - the physicists.

  14. Shape Deformations in Atomic Nuclei

    CERN Document Server

    Hamamoto, Ikuko

    2011-01-01

    The ground states of some nuclei are described by densities and mean fields that are spherical, while others are deformed. The existence of non-spherical shape in nuclei represents a spontaneous symmetry breaking.

  15. Hot Tickets

    Science.gov (United States)

    Fox, Bette-Lee; Hoffert, Barbara; Kuzyk, Raya; McCormack, Heather; Williams, Wilda

    2008-01-01

    This article describes the highlights of this year's BookExpo America (BEA) held at the Los Angeles Convention Center. The attendees at BEA had not minded that the air was recycled, the lighting was fluorescent, and the food was bad. The first hot book sighting came courtesy of Anne Rice. Michelle Moran, author of newly published novel, "The…

  16. Ultra High Energy Nuclei Propagation

    CERN Document Server

    Aloisio, Roberto

    2008-01-01

    We discuss the problem of ultra high energy nuclei propagation in astrophysical backgrounds. We present a new analytical computation scheme based on the hypothesis of continuos energy losses in a kinetic formulation of the particles propagation. This scheme enables the computation of the fluxes of ultra high energy nuclei as well as the fluxes of secondaries (nuclei and nucleons) produced by the process of photo-disintegration suffered by nuclei.

  17. A novel ion source for the calibration of an MRTOF Mass Spectrograph to be used in superheavy elements mass measurements

    CERN Document Server

    Naimi, S; Ito, Y; Mita, H; Okada, K; Ozawa, A; Schury, P; Sonoda, T; Takamine, A; Wada, M; Wollnik, H

    2012-01-01

    A novel ion source based on electrospray ionization and radiofrequency carpet technique has been built. This ion source is designed to deliver relatively heavy molecules for the calibration of a multi reflection time-of-flight mass spectrograph (MRTOF-MS) that will be used for direct mass measurements of superheavy elements. The operation of the ion source as well as the analysis by the MRTOF-MS with heavy molecular ions is described.

  18. Neutrino pair emission from thermally excited nuclei in stellar collapse

    CERN Document Server

    Dzhioev, Alan A

    2013-01-01

    We examine the rate of neutrino-antineutrino pair emission by hot nuclei in collapsing stellar cores. The rates are calculated assuming that only allowed charge-neutral Gamow-Teller (GT$_0$) transitions contribute to the decay of thermally excited nuclear states. To obtain the GT$_0$ transition matrix elements, we employ the quasiparticle random phase approximation extended to finite temperatures within the thermo field dynamics formalism. The decay rates and the energy emission rates are calculated for the sample nuclei ${}^{56}$Fe and $^{82}$Ge at temperatures relevant to core collapse supernovae.

  19. Bubble nuclei; Noyaux Bulles

    Energy Technology Data Exchange (ETDEWEB)

    Legoll, F. [Service de Physique Theorique, CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France)

    1998-07-22

    For nuclei with very high electrical charge, the Coulomb field is expected to drive the protons away from the centre to the surface of the nucleus. Such a nucleus would be no more compact but look like a bubble. The goal of this work is to confirm this idea. We are interested in only the ground state of spherical nuclei. We use the Skyrme potential with the Sly4 parametrization to calculate the mean-field Hamiltonian. Paring correlations are described by a surface-active delta paring interaction. In its ground state the nucleus {sup A=900} X{sub Z=274} is shown to be a bubble. Another stable state is found with a little higher energy: it is also a bubble. (author) 11 refs., 18 figs., 33 tabs.

  20. Bubble nuclei; Noyaux Bulles

    Energy Technology Data Exchange (ETDEWEB)

    Legoll, F. [Service de Physique Theorique, CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France)

    1998-07-22

    For nuclei with very high electrical charge, the Coulomb field is expected to drive the protons away from the centre to the surface of the nucleus. Such a nucleus would be no more compact but look like a bubble. The goal of this work is to confirm this idea. We are interested in only the ground state of spherical nuclei. We use the Skyrme potential with the Sly4 parametrization to calculate the mean-field Hamiltonian. Paring correlations are described by a surface-active delta paring interaction. In its ground state the nucleus {sup A=900} X{sub Z=274} is shown to be a bubble. Another stable state is found with a little higher energy: it is also a bubble. (author) 11 refs., 18 figs., 33 tabs.

  1. SYMMETRICAL AND ASYMMETRIC TERNARY FISSION OF HOT NUCLEI

    NARCIS (Netherlands)

    SIWEKWILCZYNSKA, K; WILCZYNSKI, J; LEEGTE, HKW; SIEMSSEN, RH; WILSCHUT, HW; GROTOWSKI, K; PANASIEWICZ, A; SOSIN, Z; WIELOCH, A

    1993-01-01

    Emission of a particles accompanying fusion-fission processes in the Ar-40 + Th-232 reaction at E(Ar-40) = 365 MeV was studied in a wide range of in-fission-plane and out-of-plane angles. The exact determination of the emission angles of both fission fragments combined with the time-of-flight measur

  2. SYMMETRICAL AND ASYMMETRIC TERNARY FISSION OF HOT NUCLEI

    NARCIS (Netherlands)

    SIWEKWILCZYNSKA, K; WILCZYNSKI, J; LEEGTE, HKW; SIEMSSEN, RH; WILSCHUT, HW; GROTOWSKI, K; PANASIEWICZ, A; SOSIN, Z; WIELOCH, A

    1993-01-01

    Emission of a particles accompanying fusion-fission processes in the Ar-40 + Th-232 reaction at E(Ar-40) = 365 MeV was studied in a wide range of in-fission-plane and out-of-plane angles. The exact determination of the emission angles of both fission fragments combined with the time-of-flight measur

  3. Symmetries in Nuclei

    CERN Document Server

    Van Isacker, P

    2010-01-01

    The use of dynamical symmetries or spectrum generating algebras for the solution of the nuclear many-body problem is reviewed. General notions of symmetry and dynamical symmetry in quantum mechanics are introduced and illustrated with simple examples such as the SO(4) symmetry of the hydrogen atom and the isospin symmetry in nuclei. Two nuclear models, the shell model and the interacting boson model, are reviewed with particular emphasis on their use of group-theoretical techniques.

  4. On Quasibound N* Nuclei

    CERN Document Server

    Kelkar, N G; Moskal, P

    2015-01-01

    The possibility for the existence of unstable bound states of the S11 nucleon resonance N$^*$(1535) and nuclei is investigated. These quasibound states are speculated to be closely related to the existence of the quasibound states of the eta mesons and nuclei. Within a simple model for the N N$^*$ interaction involving a pion and eta meson exchange, N$^*$-nucleus potentials for N*-$^3$He and N*-$^{24}$Mg are evaluated and found to be of a Woods-Saxon like form which supports two to three bound states. In case of N*-$^3$He, one state bound by only a few keV and another by 4 MeV is found. The results are however quite sensitive to the N N$^*$ $\\pi$ and N N$^*$ $\\eta$ vertex parameters. A rough estimate of the width of these states, based on the mean free path of the exchanged mesons in the nuclei leads to very broad states with $\\Gamma \\sim$ 80 and 110 MeV for N*-$^3$He and N*-$^{24}$Mg respectively.

  5. Hot Money,Hot Problems

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    After emerging from the economic doldrums, developing economies are now confronted with a new danger-a flood of international hot money. But how has the speculative capital circumvented regulatory controls and what are the consequences concerning the stability of the developing world? Zhao Zhongwei, a senior researcher with the Institute of World Politics and Economics at the Chinese Academy of Social Sciences, discussed these issues in an article recently published in the China Securities Journal. Edited excerpts follow

  6. Skyrmions and Nuclei

    Science.gov (United States)

    Battye, R. A.; Manton, N. S.; Sutcliffe, P. M.

    We review recent work on the modelling of atomic nuclei as quantised Skyrmions, using Skyrme's original model with pion fields only. Skyrmions are topological soliton solutions, whose conserved topological charge B is identified with the baryon number of a nucleus. Apart from an energy and length scale, the Skyrme model has just one dimensionless parameter m, proportional to the pion mass. It has been found that a good fit to experimental nuclear data requires m to be of order 1. The Skyrmions for B up to 7 have been known for some time, and are qualitatively insensitive to whether m is zero or of order 1. However, for baryon numbers B = 8 and above, the Skyrmions have quite a compact structure for m of order 1, rather than the hollow polyhedral structure found when m = 0. One finds for baryon numbers which are multiples of four, that the Skyrmions are composed of B = 4 sub-units, as in the α-particle model of nuclei. The rational map ansatz gives a useful approximation to the Skyrmion solutions for all baryon numbers when m = 0. For m of order 1, it gives a good approximation for baryon numbers up to 7, and generalisations of this ansatz are helpful for higher baryon numbers. We briefly review the work from the 1980s and 90s on the semiclassical rigidbody quantisation of Skyrmions for B = 1, 2, 3 and 4. We then discuss more recent work extending this method to B = 6, 7, 8, 10 and 12. We determine the quantum states of the Skyrmions, finding their spins, isospins and parities, and compare with the experimental data on the ground and excited states of nuclei up to mass number 12.

  7. Active galactic nuclei

    CERN Document Server

    Beckmann, Volker

    2012-01-01

    This AGN textbook includes phenomena based on new results in the X-Ray domain from new telescopes such as Chandra and XMM Newton not mentioned in any other book. Furthermore, it considers also the Fermi Gamma Ray Space Telescope with its revolutionary advances of unprecedented sensitivity, field of view and all-sky monitoring. Those and other new developments as well as simulations of AGN merging events and formations, enabled through latest super-computing capabilities. The book gives an overview on the current knowledge of the Active Galacitc Nuclei phenomenon. The spectral energy d

  8. Active galactic nuclei

    CERN Document Server

    Blandford, RD; Woltjer, L

    1990-01-01

    Starting with this volume, the Lecture Notes of the renowned Advanced Courses of the Swiss Society for Astrophysics and Astronomy will be published annually. In each course, three extensive lectures given by leading experts in their respective fields cover different and essential aspects of the subject. The 20th course, held at Les Diablerets in April 1990, dealt with current research on active galactic nuclei; it represents the most up-to-date views on the subject, presented with particular regard for clarity. The previous courses considered a wide variety of subjects, beginning with ""Theory

  9. Visibility of comet nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Ney, E.P.

    1982-01-22

    Photography of the nucleus of comet Halley is the goal of several planned space missions. The nucleus of a comet is surrounded by a cloud of dust particles. If this cloud is optically thick, it will prevent observation of the nuclear surface. Broadband photometry of nine comets has been analyzed to determine the visibility of their nuclei. Only in the case of comet West near perihelion was the dust dense enough to interfere with imaging. Comparison of the visual brightness of the well-observed comets with that of Halley in 1910 leads to the conclusion that the nucleus of Halley can be imaged without significant obscuration by the dust.

  10. Are 'hot spots' hot spots?

    Science.gov (United States)

    Foulger, Gillian R.

    2012-07-01

    The term 'hot spot' emerged in the 1960s from speculations that Hawaii might have its origins in an unusually hot source region in the mantle. It subsequently became widely used to refer to volcanic regions considered to be anomalous in the then-new plate tectonic paradigm. It carried with it the implication that volcanism (a) is emplaced by a single, spatially restricted, mongenetic melt-delivery system, assumed to be a mantle plume, and (b) that the source is unusually hot. This model has tended to be assumed a priori to be correct. Nevertheless, there are many geological ways of testing it, and a great deal of work has recently been done to do so. Two fundamental problems challenge this work. First is the difficulty of deciding a 'normal' mantle temperature against which to compare estimates. This is usually taken to be the source temperature of mid-ocean ridge basalts (MORBs). However, Earth's surface conduction layer is ˜200 km thick, and such a norm is not appropriate if the lavas under investigation formed deeper than the 40-50 km source depth of MORB. Second, methods for estimating temperature suffer from ambiguity of interpretation with composition and partial melt, controversy regarding how they should be applied, lack of repeatability between studies using the same data, and insufficient precision to detect the 200-300 °C temperature variations postulated. Available methods include multiple seismological and petrological approaches, modelling bathymetry and topography, and measuring heat flow. Investigations have been carried out in many areas postulated to represent either (hot) plume heads or (hotter) tails. These include sections of the mid-ocean spreading ridge postulated to include ridge-centred plumes, the North Atlantic Igneous Province, Iceland, Hawaii, oceanic plateaus, and high-standing continental areas such as the Hoggar swell. Most volcanic regions that may reasonably be considered anomalous in the simple plate-tectonic paradigm have been

  11. Elusive Active Galactic Nuclei

    CERN Document Server

    Maiolino, R; Gilli, R; Nagar, N M; Bianchi, S; Böker, T; Colbert, E; Krabbe, A; Marconi, A; Matt, G; Salvati, M

    2003-01-01

    A fraction of active galactic nuclei do not show the classical Seyfert-type signatures in their optical spectra, i.e. they are optically "elusive". X-ray observations are an optimal tool to identify this class of objects. We combine new Chandra observations with archival X-ray data in order to obtain a first estimate of the fraction of elusive AGN in local galaxies and to constrain their nature. Our results suggest that elusive AGN have a local density comparable to or even higher than optically classified Seyfert nuclei. Most elusive AGN are heavily absorbed in the X-rays, with gas column densities exceeding 10^24 cm^-2, suggesting that their peculiar nature is associated with obscuration. It is likely that in elusive AGN, the nuclear UV source is completely embedded and the ionizing photons cannot escape, which prevents the formation of a classical Narrow Line Region. Elusive AGN may contribute significantly to the 30 keV bump of the X-ray background.

  12. Electron scattering for exotic nuclei

    Indian Academy of Sciences (India)

    Toshimi Suda

    2014-11-01

    A brand-new electron scattering facility, the SCRIT Electron Scattering Facility, will soon start its operation at RIKEN RI Beam Factory, Japan. This is the world’s first electron scattering facility dedicated to the structure studies of short-lived nuclei. The goal of this facility is to determine the charge density distributions of short-lived exotic nuclei by elastic electron scattering. The first collision between electrons and exotic nuclei will be observed in the year 2014.

  13. Super-heavy electron material as metallic refrigerant for adiabatic demagnetization cooling.

    Science.gov (United States)

    Tokiwa, Yoshifumi; Piening, Boy; Jeevan, Hirale S; Bud'ko, Sergey L; Canfield, Paul C; Gegenwart, Philipp

    2016-09-01

    Low-temperature refrigeration is of crucial importance in fundamental research of condensed matter physics, because the investigations of fascinating quantum phenomena, such as superconductivity, superfluidity, and quantum criticality, often require refrigeration down to very low temperatures. Currently, cryogenic refrigerators with (3)He gas are widely used for cooling below 1 K. However, usage of the gas has been increasingly difficult because of the current worldwide shortage. Therefore, it is important to consider alternative methods of refrigeration. We show that a new type of refrigerant, the super-heavy electron metal YbCo2Zn20, can be used for adiabatic demagnetization refrigeration, which does not require (3)He gas. This method has a number of advantages, including much better metallic thermal conductivity compared to the conventional insulating refrigerants. We also demonstrate that the cooling performance is optimized in Yb1-x Sc x Co2Zn20 by partial Sc substitution, with x ~ 0.19. The substitution induces chemical pressure that drives the materials to a zero-field quantum critical point. This leads to an additional enhancement of the magnetocaloric effect in low fields and low temperatures, enabling final temperatures well below 100 mK. This performance has, up to now, been restricted to insulators. For nearly a century, the same principle of using local magnetic moments has been applied for adiabatic demagnetization cooling. This study opens new possibilities of using itinerant magnetic moments for cryogen-free refrigeration.

  14. Fusion Barrier of Super-heavy Elements in a Generalized Liquid Drop Model

    Institute of Scientific and Technical Information of China (English)

    CHENBao-Qiu; MAZhong-Yu

    2004-01-01

    The macroscopic deformed potential energies for super-heavy elements Z = 110,112,114,116,118 arc determined within a generalized liquid drop model (GLDM). A quasi-molecular mechanism is introduced to describe the deformation of a nucleus in the GLDM and the shell model simultaneously. The macroscopic energy of a twocenter nuclear system in the GLDM includes the volume-, surface-, and Coulomb-energies, the proximity effect at each mass asymmetry, and accurate nuclear radius. The shell correction is calculated by the Strutinsky method and the microscopic single particle energies are derived from a shell model in an axially deformed Woods-Saxon potential with the quasi-molecular shape. The total potential energy of a nucleus can be calculated by the macro-microscopic method as the summation of the liquid-drop energy and the Strutinsky shell correction. The theory is applied to predict the fusion barriers of the cold reactions 64Ni + 208 spb → 272 110*, 70Zn + 208pb → 278 112*, 76Ge + 208seb → 284 114*,82Se + 208pb → 29 116*, 86Kr + 208pb → 294 118*. It is found that the neck in the quasi-molecular shape is responsible for the deep valley of the fusion barrier. In the cold fusion path, double-hump fusion barriers could be predicted by the shell corrections and complete fusion events may occur.

  15. Fusion Barrier of Super-heavy Elements in a Generalized Liquid Drop Model

    Institute of Scientific and Technical Information of China (English)

    CHEN Bao-Qiu; MA Zhong-Yu

    2004-01-01

    The macroscopic deformed potential energies for super-heavy elements Z = 110,112,114,116,118 are determined within a generalized liquid drop model (GLDM). A quasi-molecular mechanism is introduced to describe the deformation of a nucleus in the GLDM and the shell model simultaneously. The macroscopic energy of a twocenter nuclear system in the GLDM includes the volume-, surface-, and Coulomb-energies, the proximity effect at each mass asymmetry, and accurate nuclear radius. The shell correction is calculated by the Strutinsky method and the microscopic single particle energies are derived from a shell model in an axially deformed Woods-Saxon potential with the quasi-molecular shape. The total potential energy of a nucleus can be calculated by the macro-microscopic method as the summation of the liquid-drop energy and the Strutinsky shell correction. The theory is applied to predict the fusion barriers of the cold reactions 64Ni + 208Pb → 272110*, 70Zn + 208Pb → 278112*, 76Ge + 208pb → 284114*,82Se + 208Pb → 290116*, 86Kr + 208Pb → 294118*. It is found that the neck in the quasi-molecular shape is responsible for the deep valley of the fusion barrier. In the cold fusion path, double-hump fusion barriers could be predicted by the shell corrections and complete fusion events may occur.

  16. Coprecipitation experiment with Sm hydroxide using a multitracer produced by nuclear spallation reaction: A tool for chemical studies with superheavy elements.

    Science.gov (United States)

    Kasamatsu, Yoshitaka; Yokokita, Takuya; Toyomura, Keigo; Shigekawa, Yudai; Haba, Hiromitsu; Kanaya, Jumpei; Huang, Minghui; Ezaki, Yutaka; Yoshimura, Takashi; Morita, Kosuke; Shinohara, Atsushi

    2016-12-01

    To establish a new methodology for superheavy element chemistry, the coprecipitation behaviors of 34 elements with samarium hydroxide were investigated using multitracer produced by a spallation of Ta. The chemical reactions were rapidly equilibrated within 10s for many elements. In addition, these elements exhibited individual coprecipitation behaviors, and the behaviors were qualitatively related to their hydroxide precipitation behaviors. It was demonstrated that the ammine and hydroxide complex formations of superheavy elements could be investigated using the established method. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Measurement of proton capture reactions in the hot cycles: an evaluation of experimental methods

    Energy Technology Data Exchange (ETDEWEB)

    Leleux, P. [Inst. de Physique Nucleaire, Univ. Catholique de Louvain, Louvain-la-Neuve (Belgium)

    1998-06-01

    In the hot cycles, most of the proton capture reactions involve radioactive nuclei in the entrance and exit channels. This paper evaluates the specific methods that were designed to measure such reactions. (orig.)

  18. Clusters in nuclei

    CERN Document Server

    Following the pioneering discovery of alpha clustering and of molecular resonances, the field of nuclear clustering is today one of those domains of heavy-ion nuclear physics that faces the greatest challenges, yet also contains the greatest opportunities. After many summer schools and workshops, in particular over the last decade, the community of nuclear molecular physicists has decided to collaborate in producing a comprehensive collection of lectures and tutorial reviews covering the field. This third volume follows the successful Lect. Notes Phys. 818 (Vol. 1) and 848 (Vol. 2), and comprises six extensive lectures covering the following topics:  - Gamma Rays and Molecular Structure - Faddeev Equation Approach for Three Cluster Nuclear Reactions - Tomography of the Cluster Structure of Light Nuclei Via Relativistic Dissociation - Clustering Effects Within the Dinuclear Model : From Light to Hyper-heavy Molecules in Dynamical Mean-field Approach - Clusterization in Ternary Fission - Clusters in Light N...

  19. Gluon density in nuclei

    CERN Document Server

    Ayala, A P; Levin, E M

    1996-01-01

    In this talk we present our detail study ( theory and numbers) [1] on the shadowing corrections to the gluon structure functions for nuclei. Starting from rather contraversial information on the nucleon structure function which is originated by the recent HERA data, we develop the Glauber approach for the gluon density in a nucleus based on Mueller formula [2] and estimate the value of the shadowing corrections in this case. Than we calculate the first corrections to the Glauber approach and show that these corrections are big. Based on this practical observation we suggest the new evolution equation which takes into account the shadowing corrections and solve it. We hope to convince you that the new evolution equation gives a good theoretical tool to treat the shadowing corrections for the gluons density in a nucleus and, therefore, it is able to provide the theoretically reliable initial conditions for the time evolution of the nucleus - nucleus cascade.

  20. Pulsars: Gigantic Nuclei

    CERN Document Server

    Xu, Renxin

    2011-01-01

    What is the real nature of pulsars? This is essentially a question of the fundamental strong interaction between quarks at low-energy scale and hence of the non-perturbative quantum chromo-dynamics, the solution of which would certainly be meaningful for us to understand one of the seven millennium prize problems (i.e., "Yang-Mills Theory") named by the Clay Mathematical Institute. After a historical note, it is argued here that a pulsar is very similar to an extremely big nucleus, but is a little bit different from the {\\em gigantic nucleus} speculated 80 years ago by L. Landau. The paper demonstrates the similarity between pulsars and gigantic nuclei from both points of view: the different manifestations of compact stars and the general behavior of the strong interaction.

  1. Nucleomorphs: enslaved algal nuclei.

    Science.gov (United States)

    Cavalier-Smith, T

    2002-12-01

    Nucleomorphs of cryptomonad and chlorarachnean algae are the relict, miniaturised nuclei of formerly independent red and green algae enslaved by separate eukaryote hosts over 500 million years ago. The complete 551 kb genome sequence of a cryptomonad nucleomorph confirms that cryptomonads are eukaryote-eukaryote chimeras and greatly illuminates the symbiogenetic event that created the kingdom Chromista and their alveolate protozoan sisters. Nucleomorph membranes may, like plasma membranes, be more enduring after secondary symbiogenesis than are their genomes. Partial sequences of chlorarachnean nucleomorphs indicate that genomic streamlining is limited by the mutational difficulty of removing useless introns. Nucleomorph miniaturisation emphasises that selection can dramatically reduce eukaryote genome size and eliminate most non-functional nuclear non-coding DNA. Given the differential scaling of nuclear and nucleomorph genomes with cell size, it follows that most non-coding nuclear DNA must have a bulk-sequence-independent function related to cell volume.

  2. Quarks in Few Body Nuclei

    Science.gov (United States)

    Holt, Roy J.

    2016-03-01

    Electron scattering at very high Bjorken x from hadrons provides an excellent test of models, has an important role in high energy physics, and from nuclei, provides a window into short range correlations. Light nuclei have a key role because of the relatively well-known nuclear structure. The development of a novel tritium target for Jefferson Lab has led to renewed interest in the mass three system. For example, deep inelastic scattering experiments in the light nuclei provide a powerful means to determine the neutron structure function. The isospin dependence of electron scattering from mass-3 nuclei provide information on short range correlations in nuclei. The program using the new tritium target will be presented along with a summary of other experiments aimed at revealing the large-x structure of the nucleon.

  3. Quarks in Few Body Nuclei

    Directory of Open Access Journals (Sweden)

    Holt Roy J.

    2016-01-01

    Full Text Available Electron scattering at very high Bjorken x from hadrons provides an excellent test of models, has an important role in high energy physics, and from nuclei, provides a window into short range correlations. Light nuclei have a key role because of the relatively well-known nuclear structure. The development of a novel tritium target for Jefferson Lab has led to renewed interest in the mass three system. For example, deep inelastic scattering experiments in the light nuclei provide a powerful means to determine the neutron structure function. The isospin dependence of electron scattering from mass-3 nuclei provide information on short range correlations in nuclei. The program using the new tritium target will be presented along with a summary of other experiments aimed at revealing the large-x structure of the nucleon.

  4. Cavitation inception from bubble nuclei

    DEFF Research Database (Denmark)

    Mørch, Knud Aage

    2015-01-01

    , and experimental investigations of bubbles and cavitation inception have been presented. These results suggest that cavitation nuclei in equilibrium are gaseous voids in the water, stabilized by a skin which allows diffusion balance between gas inside the void and gas in solution in the surrounding liquid....... The cavitation nuclei may be free gas bubbles in the bulk of water, or interfacial gaseous voids located on the surface of particles in the water, or on bounding walls. The tensile strength of these nuclei depends not only on the water quality but also on the pressure-time history of the water. A recent model......The tensile strength of ordinary water such as tap water or seawater is typically well below 1 bar. It is governed by cavitation nuclei in the water, not by the tensile strength of the water itself, which is extremely high. Different models of the nuclei have been suggested over the years...

  5. The cochlear nuclei of snakes.

    Science.gov (United States)

    Miller, M R

    1980-08-15

    The cochlear nuclei of three burrowing snakes (Xenopeltis unicolor, Cylindrophis rufus, and Eryx johni) and three non-burrowing snakes (Epicrates cenchris, Natrix sipedon, and Pituophis catenifer) were studied. The posterior branch of the statoacoustic nerve and its posterior ganglion were destroyed and the degenerated nerve fibers and terminals traced to primary cochlear nuclei in 13 specimens of Pituophis catenifer. All these snake species possess three primary and one secondary cochlear nuclei. The primary cochlear nuclei consist of a small nucleus angularis located at the cerebello-medullary junction and a fairly large nucleus magnocellularis forming a dorsal cap over the cephalic end of the alar eminence. Nucleus magnocellularis may be subdivided into a medially placed group of rounder cells, nucleus magnocellularis medialis, and a laterally placed group of more ovate and paler-staining cells, nucleus magnocellularis lateralis. A small but well-defined secondary nucleus which showed no degenerated nerve terminals after nerve root section, nucleus laminaris, underlies the cephalic part of both nucleus magnocellularis medialis and nucleus magnocellularis lateralis. Larger and better-developed cochlear nuclei were found in burrowing species than in non-burrowing species of snakes. Of the three burrowing species studied, Xenopeltis showed the greatest development of cochlear nuclei; Eryx cochlear nuclei were not quite as large but were better differentiated than in Xenopeltis; and Cylindrophis cochlear nuclei were fairly large but not as well developed nor as well differentiated as in either Xenopeltis or Eryx. The cochlear nuclei of the three non-burrowing snakes, Epicrates, Natrix, and Pituophis, were not as large nor as well developed as those of the burrowing snakes. There is some, but not complete, correlation between cochlear development and papilla basilaris length and number of hair cells. Thus, Xenopeltis and Eryx, with well-developed cochlear nuclei

  6. Collective excitations in nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Chomaz, Ph

    1997-12-31

    The properties of the nucleus cannot be reduced to the properties of its constituents: it is a complex system. The fact that many properties of the nucleus are consequences of the existence of mean-field potential is a manifestation of this complexity. In particular the nucleons can thus self-organize in collective motions such as giant resonances. Therefore the study of these collective motions is a very good to understand the properties of the nucleus itself. The purpose of this article was to stress some aspects of these collective vibrations. In particular we have studied how an ensemble of fermions as the nucleus can self-organize in collective vibrations which are behaving like a gas of bosons in weak interaction. The understanding of these phenomena remains one of the important subjects of actually in the context of quantal systems in strong interaction. In particular the study of the states with one or two vibration quanta provides a direct information on the structure if nuclei close to their ground states. (author) 270 refs.

  7. Gluon density in nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Ayala, A.L. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Fisica][Pelotas Univ., RS (Brazil). Inst. de Fisica e Matematica; Ducati, M.B.G. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Fisica; Levin, E.M. [Fermi National Accelerator Lab., Batavia, IL (United States)][Nuclear Physics Inst., St. Petersburg (Russian Federation)

    1996-10-01

    In this talk we present our detailed study (theory and numbers) on the shadowing corrections to the gluon structure functions for nuclei. Starting from rather controversial information on the nucleon structure function which is originated by the recent HERA data, we develop the Glauber approach for the gluon density in a nucleus based on Mueller formula and estimate the value of the shadowing corrections in this case. Then we calculate the first corrections to the Glauber approach and show that these corrections are big. Based on this practical observation we suggest the new evolution equation which takes into account the shadowing corrections and solve it. We hope to convince you that the new evolution equation gives a good theoretical tool to treat the shadowing corrections for the gluons density in a nucleus and, therefore, it is able to provide the theoretically reliable initial conditions for the time evolution of the nucleus-nucleus cascade. The initial conditions should be fixed both theoretically and phenomenologically before to attack such complicated problems as the mixture of hard and soft processes in nucleus-nucleus interactions at high energy or the theoretically reliable approach to hadron or/and parton cascades for high energy nucleus-nucleus interaction. 35 refs., 24 figs., 1 tab.

  8. Spectroscopy of heavy fissionable nuclei

    Indian Academy of Sciences (India)

    S K Tandel

    2015-09-01

    Structural studies of heavy nuclei are quite challenging due to increased competition from fission, particularly at high spins. Nuclei in the actinide region exhibit a variety of interesting phenomena. Recent advances in instrumentation and analysis techniques have made feasible sensitive measurements of nuclei populated with quite low cross-sections. These include isomers and rotational band structures in isotopes of Pu ( = 94) to Rf ( = 104), and octupole correlations in the Th ( = 90) region. The obtained experimental data have provided insights on various aspects like moments of inertia and nucleon alignments at high spins, quasiparticle energies and evolution of quadrupole and octupole collectivity, among others. An overview of some of these results is presented.

  9. Synthesis of superheavy elements and dinuclear-system concept of compound-nucleus formation

    Energy Technology Data Exchange (ETDEWEB)

    Antonenko, N.V.; Adamian, G.G.; Cherepanov, E.A. [Joint Institute for Nuclear Research, Dubna (Russian Federation)] [and others

    1996-12-31

    Dinuclear system concept is applied to the analysis of reactions used for the synthesis of elements with Z = 110, 112, 114, and 116. The inner fusion barriers obtained for these reactions are in good agreement with the experimental estimations resulted from the excitation energies of compound nuclei. A model is suggested for the calculation of the competition between complete fusion and quasifission in reactions with heavy nuclei. The fusion rate through the inner fusion barrier in mass asymmetry is found by using the multidimensional Kramers-type stationary solution of the Fokker-Planck equation. The influence of dissipative effects on the dynamics of nuclear fusion is considered.

  10. Pseudospin Dynamical Symetry in Nuclei

    CERN Document Server

    Ginocchio, Joseph N

    2014-01-01

    Pseudospin symmetry has been useful in understanding atomic nuclei. We review the arguments that this symmetry is a relativistic symmetry. The condition for this symmetry is that the sum of the vector and scalar potentials in the Dirac Hamiltonian is a constant. We give the generators of pseudospin symmetry. We review some of the predictions that follow from this insight into the relativistic origins of pseudospin symmetry. Since in nuclei the sum of the scalar and vector potentials is not zero but is small, we discuss preliminary investigations into the conditions on the potentials to produce partial dynamic pseudospin symmetry. Finally we show that approximate pseudospin symmetry in nuclei predicts approximate spin symmetry in anti-nucleon scattering from nuclei.

  11. Physics with loosely bound nuclei

    Indian Academy of Sciences (India)

    Chhanda Samanta

    2001-08-01

    The essential aspect of contemporary physics is to understand properties of nucleonic matter that constitutes the world around us. Over the years research in nuclear physics has provided strong guidance in understanding the basic principles of nuclear interactions. But, the scenario of nuclear physics changed drastically as the new generation of accelerators started providing more and more rare isotopes, which are away from the line of stability. These weakly bound nuclei are found to exhibit new forms of nuclear matter and unprecedented exotic behaviour. The low breakup thresholds of these rare nuclei are posing new challenges to both theory and experiments. Fortunately, nature has provided a few loosely bound stable nuclei that have been studied thoroughly for decades. Attempts are being made to find a consistent picture for the unstable nuclei starting from their stable counterparts. Some significant differences in the structure and reaction mechanisms are found.

  12. Model Experiments on Chemical Properties of Superheavy Elements in Aqueous Solutions

    CERN Document Server

    Szeglowski, Z

    2003-01-01

    This paper presents a brief review of model experiments on investigation of chemical properties of transactinide elements, ranging from 104 to 116. The possibilities of isolation of the nuclei of these elements from nuclear reaction products, using the ion-exchange method, are also considered.

  13. Geometrical track parameters in the pallasite olivine: Identification of the cosmic ray heavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Kashkarov, L.L. [Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, Kosygin Str. 19, Moscow 119991 (Russian Federation)], E-mail: cosmo@geokhi.ru; Polukhina, N.G.; Starkov, N.I. [Lebedev Physical Institute, Russian Academy of Sciences, Leninskii pr. 53, Moscow 119991 (Russian Federation); Kalinina, G.V.; Ivliev, A. [Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, Kosygin Str. 19, Moscow 119991 (Russian Federation); Aleksandrov, A.B.; Goncharova, L.A.; Tarasova, I. Yu. [Lebedev Physical Institute, Russian Academy of Sciences, Leninskii pr. 53, Moscow 119991 (Russian Federation)

    2008-08-15

    The geometry characteristics of chemically etched tracks in the not annealed olivine crystals from pallasite meteorites are investigated with the search and identification goal of fossil tracks of galactic cosmic ray heavy and superheavy nuclei. The chosen methodology is based on precise measurements of the nucleus track parameters in the course of chemical etching of the olivine crystals. Geometric parameters of individual tracks are traced and measured in course of their step-by-step chemical etching by using a modern high-precision, completely automated facility PAVICOM designed at the Lebedev Physical Institute of Russian Academy of Sciences. A method of the layer-by-layer removal of olivine material is employed, which allows the tracks to be studied over the whole crystal volume under study. It is planned to measure the next main parameters: the cone length and diameters of etched track within the initial, high-energy section of its formation; the total residual range and diameters, corresponding to saturation zone of the primary ionization; and the etching rate along the different parts of tracks, the starting inter-volume olivine crystal point for which were fixed. The preliminary experimental results obtained for 42 tracks, detected and analyzed in the Marjalahti pallasite olivine crystals, are presented.

  14. Four hot DOGs in the microwave

    CERN Document Server

    Frey, S; Gabányi, K É; An, T

    2016-01-01

    Hot dust-obscured galaxies (hot DOGs) are a rare class of hyperluminous infrared galaxies identified with the Wide-field Infrared Survey Explorer (WISE) satellite. The majority of them is at high redshifts (z~2-3), at the peak epoch of star formation in the Universe. Infrared, optical, radio, and X-ray data suggest that hot DOGs contain heavily obscured, extremely luminous active galactic nuclei (AGN). This class may represent a short phase in the life of the galaxies, signifying the transition from starburst- to AGN-dominated phases. Hot DOGs are typically radio-quiet, but some of them show mJy-level emission in the radio (microwave) band. We observed four hot DOGs using the technique of very long baseline interferometry (VLBI). The 1.7-GHz observations with the European VLBI Network (EVN) revealed weak radio features in all sources. The radio is free from dust obscuration and, at such high redshifts, VLBI is sensitive only to compact structures that are characteristic of AGN activity. In two cases (WISE J07...

  15. NuSTAR observations of WISE J1036+0449, a galaxy at z ∼ 1 obscured by hot dust

    DEFF Research Database (Denmark)

    Ricci, C.; Assef, R. J.; Stern, D.

    2017-01-01

    Hot dust-obscured galaxies (hot DOGs), selected from Wide-Field Infrared Survey Explorer’s all-sky infrared survey, host some of the most powerful active galactic nuclei known and may represent an important stage in the evolution of galaxies. Most known hot DOGs are located at z > 1.5, due in par...

  16. Systematic study on probable projectile-target combinations for the synthesis of the $^{302}$120 superheavy nucleus

    CERN Document Server

    Santhosh, K P

    2016-01-01

    Probable projectile-target combinations for the synthesis of superheavy element $^{302}$120 have been studied taking Coulomb and proximity potential as the interaction barrier. The probabilities of compound nucleus formation, PCN for the projectile-target combinations found in the cold reaction valley of $^{302}$120 are estimated. At energies near and above the Coulomb barrier, we have calculated the capture, fusion and evaporation residue cross sections for the reactions of all the probable projectile-target combinations so as to predict the most promising projectile-target combinations for the synthesis of SHE $^{302}$120 in heavy ion fusion reactions. The calculated fusion and evaporation cross section for the more asymmetric (hotter) projectile-target combination is found to be higher than the less asymmetric (colder) combination. It can be seen from the nature of quasi-fission barrier height, mass asymmetry, probability of compound nucleus formation, survival probability and excitation energy, the system...

  17. Photodissociation of neutron deficient nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Sonnabend, K.; Babilon, M.; Hasper, J.; Mueller, S.; Zarza, M.; Zilges, A. [TU Darmstadt, Institut fuer Kernphysik, Darmstadt (Germany)

    2006-03-15

    The knowledge of the cross sections for photodissociation reactions like e.g. ({gamma}, n) of neutron deficient nuclei is of crucial interest for network calculations predicting the abundances of the so-called p nuclei. However, only single cross sections have been measured up to now, i.e., one has to rely nearly fully on theoretical predictions. While the cross sections of stable isotopes are accessible by experiments using real photons, the bulk of the involved reactions starts from unstable nuclei. Coulomb dissociation (CD) experiments in inverse kinematics might be a key to expand the experimental database for p-process network calculations. The approach to test the accuracy of the CD method is explained. (orig.)

  18. Studies of exotic light nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Cerny, J.

    1976-05-01

    For neutron-deficient nuclei, extension of the T/sub z/ = --3/2 series of strong beta-delayed proton precursors to /sup 61/Ge is discussed. For neutron-excess nuclei, heavy-ion induced, multi-nucleon transfer reaction studies of masses and energy levels of 2sld shell nuclei with T/sub z/ greater than or equal to 5/2 are covered. In addition, preliminary attempts to employ the (/sup 7/Li,/sup 2/He) reaction for the latter studies are shown; a new detection system capable of observing unbound final states as reaction products is demonstrated via investigations of the (..cap alpha..,/sup 2/He) reaction.

  19. A relativistic symmetry in nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Ginocchio, J N [MS B283, Theoretical Division, Los Alamos National Laboratory Los Alamos, New Mexico 87545 (Mexico)

    2007-11-15

    We review some of the empirical and theoretical evidence supporting pseudospin symmetry in nuclei as a relativistic symmetry. We review the case that the eigenfunctions of realistic relativistic nuclear mean fields approximately conserve pseudospin symmetry in nuclei. We discuss the implications of pseudospin symmetry for magnetic dipole transitions and Gamow-Teller transitions between states in pseudospin doublets. We explore a more fundamental rationale for pseudospin symmetry in terms of quantum chromodynamics (QCD), the basic theory of the strong interactions. We show that pseudospin symmetry in nuclei implies spin symmetry for an anti-nucleon in a nuclear environment. We also discuss the future and what role pseudospin symmetry may be expected to play in an effective field theory of nucleons.

  20. Photoproduction of mesons off nuclei

    CERN Document Server

    Krusche, B

    2011-01-01

    Recent results for the photoproduction of mesons off nuclei are reviewed. These experiments have been performed for two major lines of research related to the properties of the strong interaction. The investigation of nucleon resonances requires light nuclei as targets for the extraction of the isospin composition of the electromagnetic excitations. This is done with quasi-free meson photoproduction off the bound neutron and supplemented with the measurement of coherent photoproduction reactions, serving as spin and/or isospin filters. Furthermore, photoproduction from light and heavy nuclei is a very efficient tool for the study of the interactions of mesons with nuclear matter and the in-medium properties of hadrons. Experiments are currently rapidly developing due to the combination of high quality tagged (and polarized) photon beams with state-of-the-art 4pi detectors and polarized targets.

  1. Octupole shapes in heavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, I.

    1994-08-01

    Theoretical calculations and measurements show the presence of strong octupole correlations in thecyround states and low-lying states of odd-mass and odd-odd nuclei in the RaPa region. Evidence for octupole correlations is provided by the observation of parity doublets and reductions in M1 matrix elements, decoupling parameters, and Coriolis matrix elements Involving high-j states. Enhancement of E1 transition rates has also been observed for some of the octupole deformed nuclei. The most convincing argument for octupole deformation is provided by the similarities of the reduced alpha decay rates to the two members of parity doublets.

  2. PDFs from nucleons to nuclei

    CERN Document Server

    Accardi, Alberto

    2016-01-01

    I review recent progress in the extraction of unpolarized parton distributions in the proton and in nuclei from a unified point of view that highlights how the interplay between high energy particle physics and lower energy nuclear physics can be of mutual benefit to either field. Areas of overlap range from the search for physics beyond the standard model at the LHC, to the study of the non perturbative structure of nucleons and the emergence of nuclei from quark and gluon degrees of freedom, to the interaction of colored probes in a cold nuclear medium.

  3. Progress report, July 1999 - June 2001; Rapport d'activite juillet 1999 - juin 2001

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    This report presents the different research programs that have been performed in the Laboratory of Corpuscular Physics (LPC). The activities and achievements have been parted under 9 headings: 1) mechanisms of production and decay of hot nuclei; 2) exotic nuclei; 3) production and properties of super-heavy nuclei; 4) theoretical physics; 5) basic interactions; 6) management of radioactive wastes (Gedeon program); 7) technical assistance, engineering, hardware; and 8) teaching and training.

  4. Production of the superheavy baryon Λ{sub c} {sub anti} {sub c}{sup *}(4209) in kaon-induced reaction

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiao-Yun [Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou (China); University of Chinese Academy of Sciences, Beijing (China); Institute of Modern Physics of CAS and Lanzhou University, Research Center for Hadron and CSR Physics, Lanzhou (China); Chen, Xu-Rong [Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou (China); Institute of Modern Physics of CAS and Lanzhou University, Research Center for Hadron and CSR Physics, Lanzhou (China)

    2015-07-15

    The production of superheavy Λ{sub c} {sub anti} {sub c}{sup *}(4209) baryon in the K{sup -}p → η{sub c}Λ process via s-channel is investigated with an effective Lagrangian approach and the isobar model. Moreover, the background from the K{sup -}p → η{sub c}Λ reaction through the t-channel with K* exchange and u-channel with nucleon exchange are also considered. The numerical results indicate it is feasible to search for the superheavy Λ{sub c} {sub anti} {sub c}{sup *}(4209) via K{sup -}p scattering. The relevant calculations not only shed light on the further experiment of searching for the Λ{sub c} {sub anti} {sub c}{sup *}(4209) through kaon-induced reaction, but also enable us to have a better understanding of the exotic baryons. (orig.)

  5. Ionization potentials and electron affinities of the superheavy elements 115-117 and their sixth-row homologues Bi, Po, and At

    Science.gov (United States)

    Borschevsky, A.; Pašteka, L. F.; Pershina, V.; Eliav, E.; Kaldor, U.

    2015-02-01

    Calculations of the first and second ionization potentials and electron affinities of superheavy elements 115-117 are presented. The calculations are performed in the framework of the Dirac-Coulomb Hamiltonian, and the results are corrected for the Breit and QED contributions. Correlation is treated by the relativistic coupled cluster approach with single, double, and perturbative triple excitations [CCSD(T)]. The same approach is used to calculate the ionization potentials and electron affinities of the lighter homologues, Bi, Po, and At. Comparison of the available experimental values for these atoms, namely, the first ionization potentials (IPs) of Bi, Po, and At and the second IP and EA of Bi, with our results shows excellent agreement, within a few hundredths of an eV, lending credence to our predictions for their superheavy homologues. High-accuracy predictions are also made for the second ionization potentials and electron affinities of Po and At, where no experiment is available.

  6. Partial Dynamical Symmetries in Nuclei

    CERN Document Server

    Leviatan, A

    2000-01-01

    Partial dynamical symmetries (PDS) are shown to be relevant to the interpretation of the $K=0_2$ band and to the occurrence of F-spin multiplets of ground and scissors bands in deformed nuclei. Hamiltonians with bosonic and fermionic PDS are presented.

  7. Multiphonon giant resonances in nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Aumann, T. [Mainz Univ. (Germany). Inst. fuer Kernchemie; Bortignon, P.F. [Milan Univ. (Italy). Dipt. di Fisica]|[Istituto Nazionale di Fisica Nucleare, Milan (Italy); Emling, H. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)

    1998-07-01

    We review the present knowledge of multiphonon giant resonances in nuclei. Theoretical concepts approaching the intrinsic structure and excitation mechanisms of multi-phonon states are discussed. The available experimental results are summarized, including a brief description of applied techniques. This review emphasizes electromagnetic excitations of double dipole resonances. Open questions and possible routes toward a solution are addressed. (orig.)

  8. Nuclear astrophysics of light nuclei

    DEFF Research Database (Denmark)

    Fynbo, Hans Otto Uldall

    2013-01-01

    A review of nuclear astrophysics of light nuclei using radioactive beams or techniques developed for radioactive beams is given. We discuss Big Bang nucleosynthesis, with special focus on the lithium problem, aspects of neutrino-physics, helium-burning and finally selected examples of studies...

  9. Low energy + scattering on = nuclei

    Indian Academy of Sciences (India)

    Swapan Das; Arun K Jain

    2003-11-01

    The data for the total cross-section of + scattering on various nuclei have been analysed in the Glauber multiple scattering theory. Energy-dependent +-nucleus optical potential is generated using the forward +-nucleon scattering amplitude and the nuclear density distribution. Along with this, the calculated total +-nucleus cross-sections using the effective +-nucleon cross-section inside the nucleus are also presented.

  10. Nuclei far from stability using exotic targets

    CERN Document Server

    Wilhelmy, J B; Brown, R E; Flynn, E R; Thomas, K E; Van der Plicht, J

    1981-01-01

    The meson factories have made possible high fluence medium energy proton beams that can be used for spallation reactions to produce macro quantities of unstable isotopes. Targets of over 10 g/cm/sup 2/ can be exposed to total fluence approaching 1 A-hour resulting in spallation yields in the 0.01-10 mg range for many isotopes of potential interest for nuclear structure studies. With the use of hot cell facilities, chemical processing can isolate the desired material and this coupled with subsequent isotope separation can result in usable quantities of material for nuclear target application. With offstable isotopes as target materials, conventional nuclear spectroscopy techniques can be employed to study nuclei far from stability. The irradiation and processing requirements for such an operation, along with the isotope production possibilities, are discussed. Also presented are initial experiments using a /sup 148/Gd (t/sub 1/2/=75a) target to perform the (p, t) reaction to establish levels in the proposed do...

  11. Hot-dome anemometry

    Science.gov (United States)

    Thompson, Brian E.

    1998-05-01

    Hot-dome anemometry obtains three components of flow velocity using an array of sensors, specifically five hot films in the present contribution, which are mounted around the hemispherical tip of a cylindrical support. Calibration for speed and angle resembles that of hot wires and split films except that the procedures accommodate heat transfer dominated by forced convection from the surface of a sphere rather than single or multiple cylinders. Measurements are obtained with hot domes, conventional hot wires, and impact probes in the wake of a wing to quantify measurement uncertainties.

  12. Rotating target wheel system for super-heavy element production at ATLAS

    CERN Document Server

    Greene, J P; Falout, J; Janssens, R V F

    2004-01-01

    A new scattering chamber housing a large diameter rotating target wheel has been designed and constructed in front of the Fragment Mass Analyzer (FMA) for the production of very heavy nuclei (Z greater than 100) using beams from the Argonne Tandem Linear Accelerator System (ATLAS). In addition to the target and drive system, the chamber is extensively instrumented in order to monitor target performance and deterioration. Capabilities also exist to install rotating entrance and exit windows for gas cooling of the target within the scattering chamber. The design and initial tests are described.

  13. Poroelasticity of cell nuclei revealed through atomic force microscopy characterization

    Science.gov (United States)

    Wei, Fanan; Lan, Fei; Liu, Bin; Liu, Lianqing; Li, Guangyong

    2016-11-01

    With great potential in precision medical application, cell biomechanics is rising as a hot topic in biology. Cell nucleus, as the largest component within cell, not only contributes greatly to the cell's mechanical behavior, but also serves as the most vital component within cell. However, cell nucleus' mechanics is still far from unambiguous up to now. In this paper, we attempted to characterize and evaluate the mechanical property of isolated cell nuclei using Atomic Force Microscopy with a tipless probe. As indicated from typical indentation, changing loading rate and stress relaxation experiment results, cell nuclei showed significant dynamically mechanical property, i.e., time-dependent mechanics. Furthermore, through theoretical analysis, finite element simulation and stress relaxation experiment, the nature of nucleus' mechanics was better described by poroelasticity, rather than viscoelasticity. Therefore, the essence of nucleus' mechanics was clarified to be poroelastic through a sophisticated analysis. Finally, we estimated the poroelastic parameters for nuclei of two types of cells through a combination of experimental data and finite element simulation.

  14. Four hot DOGs in the microwave

    Science.gov (United States)

    Frey, Sándor; Paragi, Zsolt; Gabányi, Krisztina Éva; An, Tao

    2016-01-01

    Hot dust-obscured galaxies (hot DOGs) are a rare class of hyperluminous infrared galaxies identified with the Wide-field Infrared Survey Explorer (WISE) satellite. The majority of them are at high redshifts (z ˜ 2-3), at the peak epoch of star formation in the Universe. Infrared, optical, radio, and X-ray data suggest that hot DOGs contain heavily obscured, extremely luminous active galactic nuclei (AGN). This class may represent a short phase in the life of the galaxies, signifying the transition from starburst- to AGN-dominated phases. Hot DOGs are typically radio-quiet, but some of them show mJy-level emission in the radio (microwave) band. We observed four hot DOGs using the technique of very long baseline interferometry (VLBI). The 1.7 GHz observations with the European VLBI Network (EVN) revealed weak radio features in all sources. The radio is free from dust obscuration and, at such high redshifts, VLBI is sensitive only to compact structures that are characteristic of AGN activity. In two cases (WISE J0757+5113, WISE J1603+2745), the flux density of the VLBI-detected components is much smaller than the total flux density, suggesting that ˜70-90 per cent of the radio emission, while still dominated by AGN, originates from angular scales larger than that probed by the EVN. The source WISE J1146+4129 appears a candidate compact symmetric object, and WISE J1814+3412 shows a 5.1 kpc double structure, reminiscent of hotspots in a medium-sized symmetric object. Our observations support that AGN residing in hot DOGs may be genuine young radio sources where starburst and AGN activities coexist.

  15. Neutrino-antineutrino pair emission from thermally excited nuclei in stellar collapse

    Science.gov (United States)

    Dzhioev, Alan A.; Vdovin, A. I.

    2014-09-01

    We examine the rate of neutrino-antineutrino pair emission by hot nuclei in collapsing stellar cores. The rates are calculated assuming that only allowed charge-neutral Gamow-Teller (GT0) transitions contribute to the decay of thermally excited nuclear states. To obtain the GT0 transition matrix elements, we employ the quasiparticle random phase approximation extended to finite temperatures within the thermo field dynamics formalism. The decay rates and the energy emission rates are calculated for the sample nuclei 56Fe and 82Ge at temperatures relevant to core collapse supernovae.

  16. Scissors Mode in Gd Nuclei

    Directory of Open Access Journals (Sweden)

    Wu C.Y.

    2012-02-01

    Full Text Available Spectra of γ rays following neutron capture at isolated resonances of 6 stable Gd isotopes were measured with highly segmented BaF2 detector DANCE at the Los Alamos LANSCE spallation neutron source. The main emphasis was put on studying the γ-cascade decay of neutron resonances to get unique information on photon strength. An analysis of the accumulated γ-ray spectra within the extreme statistical model leads to an inescapable conclusion that scissors mode resonances are built not only on the ground-state, but also on excited levels in all product nuclei studied. The results on summed B(M1↑ strength and energy of the scissors mode are compared with systematics of scissors mode parameters for the ground-state transitions deduced from nuclear resonance fluorescence measurements. A specific feature of our experiments is the investigation of scissors mode of odd nuclei, for which the nuclear resonance fluorescence provides only limited information.

  17. Scissors Mode in Gd Nuclei

    Science.gov (United States)

    Kroll, J.; Baramsai, B.; Becker, J. A.; Bečvář, F.; Bredeweg, T. A.; Couture, A.; Chyzh, A.; Dashdorj, D.; Haight, R. C.; Jandel, M.; Krtička, M.; Mitchell, G. E.; O'Donnell, J. M.; Parker, W.; Rundberg, R. S.; Ullmann, J. L.; Vieira, G. J.; Walker, C. L.; Wilhelmy, J. B.; Wouters, J. M.; Wu, C. Y.

    2012-02-01

    Spectra of γ rays following neutron capture at isolated resonances of 6 stable Gd isotopes were measured with highly segmented BaF2 detector DANCE at the Los Alamos LANSCE spallation neutron source. The main emphasis was put on studying the γ-cascade decay of neutron resonances to get unique information on photon strength. An analysis of the accumulated γ-ray spectra within the extreme statistical model leads to an inescapable conclusion that scissors mode resonances are built not only on the ground-state, but also on excited levels in all product nuclei studied. The results on summed B(M1)↑ strength and energy of the scissors mode are compared with systematics of scissors mode parameters for the ground-state transitions deduced from nuclear resonance fluorescence measurements. A specific feature of our experiments is the investigation of scissors mode of odd nuclei, for which the nuclear resonance fluorescence provides only limited information.

  18. Evolution of active galactic nuclei

    CERN Document Server

    Merloni, Andrea

    2012-01-01

    [Abriged] Supermassive black holes (SMBH) lurk in the nuclei of most massive galaxies, perhaps in all of them. The tight observed scaling relations between SMBH masses and structural properties of their host spheroids likely indicate that the processes fostering the growth of both components are physically linked, despite the many orders of magnitude difference in their physical size. This chapter discusses how we constrain the evolution of SMBH, probed by their actively growing phases, when they shine as active galactic nuclei (AGN) with luminosities often in excess of that of the entire stellar population of their host galaxies. Following loosely the chronological developments of the field, we begin by discussing early evolutionary studies, when AGN represented beacons of light probing the most distant reaches of the universe and were used as tracers of the large scale structure. This early study turned into AGN "Demography", once it was realized that the strong evolution (in luminosity, number density) of ...

  19. Proton scattering from unstable nuclei

    Indian Academy of Sciences (India)

    Y Blumenfeld; E Khan; F Maréchal; T Suomijärvi

    2001-08-01

    Recent improvements in the intensities and optical qualities of radioactive beams have made possible the study of elastic and inelastic proton scattering on unstable nuclei. The design and performances of an innovative silicon strip detector array devoted to such experiments are described. The quality of the data obtained are illustrated with recent results obtained at the GANIL facility for unstable oxygen, sulfur and argon isotopes. Methods to analyse the data using phenomenological and microscopic optical model potentials are discussed.

  20. Strange neutral currents in nuclei

    CERN Document Server

    Ressell, M T; Aufderheide, M B; Bloom, S D; Resler, D A

    1995-01-01

    We examine the effects on the nuclear neutral current Gamow-Teller (GT) strength of a finite contribution from a polarized strange quark sea. We perform nuclear shell model calculations of the neutral current GT strength for a number of nuclei likely to be present during stellar core collapse. We compare the GT strength when a finite strange quark contribution is included to the strength without such a contribution. As an example, the process of neutral current nuclear de-excitation via \

  1. Weak pion production from nuclei

    Indian Academy of Sciences (India)

    S K Singh; M Sajjad Athar; Shakeb Ahmad

    2006-04-01

    The charged current pion production induced by neutrinos in 12C, 16O and 56Fe nuclei has been studied. The calculations have been done for the coherent as well as the incoherent processes assuming dominance and takes into account the effect of Pauli blocking, Fermi motion and the renormalization of in the nuclear medium. The pion absorption effects have also been taken into account.

  2. Triaxial rotation in atomic nuclei

    Institute of Scientific and Technical Information of China (English)

    CHEN Yong-Shou; GAO Zao-Chun

    2009-01-01

    The Projected Shell Model has been developed to include the spontaneously broken axial symmetry so that the rapidly rotating triaxial nuclei can be described microscopically. The theory provides an useful tool to gain an insight into how a triaxial nucleus rotates, a fundamental question in nuclear structure. We shall address some current interests that are strongly associated with the triaxial rotation. A feasible method to explore the problem has been suggested.

  3. Double pion photoproduction in nuclei

    CERN Document Server

    Vicente-Vacas, M J; Gómez-Tejedor, J A; Vicente-Vacas, M J; Oset, E; Gómez Tejedor, J A

    1994-01-01

    Abstract: The inclusive A(gamma,pi+ pi-)X reaction is studied theoretically. A sizeable enhancement of the cross section is found, in comparison with the scaling of the deuteron cross section (sigma_deuteron * A/2). This enhancement is due to the modifications in the nuclear medium of the gamma N ----> pi pi N amplitude and the pion dispersion relation. The enhancement is found to be bigger than the one already observed in the (pi,pi pi) reaction in nuclei.

  4. Continuum spectroscopy of light nuclei

    Directory of Open Access Journals (Sweden)

    Charity R. J.

    2016-01-01

    Full Text Available Resonance spectroscopy of light nuclei is discussed with emphasis on the invariant-mass measurements performed with the HiRA detector. For three-body exit channels, we consider the exact conditions necessary such that the decay can be described as either sequential or prompt. However experimentally, we find some cases where the decay is intermediate between these two limits. Finally, two-proton decay from isobaric analog states is discussed.

  5. Geometric symmetries in light nuclei

    CERN Document Server

    Bijker, Roelof

    2016-01-01

    The algebraic cluster model is is applied to study cluster states in the nuclei 12C and 16O. The observed level sequences can be understood in terms of the underlying discrete symmetry that characterizes the geometrical configuration of the alpha-particles, i.e. an equilateral triangle for 12C, and a regular tetrahedron for 16O. The structure of rotational bands provides a fingerprint of the underlying geometrical configuration of alpha-particles.

  6. Dynamical approach to fusion-fission process in superheavy mass region

    Directory of Open Access Journals (Sweden)

    Aritomo Y.

    2012-10-01

    Full Text Available In order to describe heavy-ion fusion reactions around the Coulomb barrier with an actinide target nucleus, we propose a model which combines the coupled-channels approach and a fluctuation-dissipation model for dynamical calculations. This model takes into account couplings to the collective states of the interacting nuclei in the penetration of the Coulomb barrier and the subsequent dynamical evolution of a nuclear shape from the contact configuration. In the fluctuation-dissipation model with a Langevin equation, the effect of nuclear orientation at the initial impact on the prolately deformed target nucleus is considered. Fusion-fission, quasifission and deep quasifission are separated as different Langevin trajectories on the potential energy surface. Using this model, we analyze the experimental data for the mass distribution of fission fragments (MDFF in the reaction of 36S+238U at several incident energies around the Coulomb barrier.

  7. Hot spot detection for breast cancer in Ki-67 stained slides: image dependent filtering approach

    Science.gov (United States)

    Niazi, M. Khalid Khan; Downs-Kelly, Erinn; Gurcan, Metin N.

    2014-03-01

    We present a new method to detect hot spots from breast cancer slides stained for Ki67 expression. It is common practice to use centroid of a nucleus as a surrogate representation of a cell. This often requires the detection of individual nuclei. Once all the nuclei are detected, the hot spots are detected by clustering the centroids. For large size images, nuclei detection is computationally demanding. Instead of detecting the individual nuclei and treating hot spot detection as a clustering problem, we considered hot spot detection as an image filtering problem where positively stained pixels are used to detect hot spots in breast cancer images. The method first segments the Ki-67 positive pixels using the visually meaningful segmentation (VMS) method that we developed earlier. Then, it automatically generates an image dependent filter to generate a density map from the segmented image. The smoothness of the density image simplifies the detection of local maxima. The number of local maxima directly corresponds to the number of hot spots in the breast cancer image. The method was tested on 23 different regions of interest images extracted from 10 different breast cancer slides stained with Ki67. To determine the intra-reader variability, each image was annotated twice for hot spots by a boardcertified pathologist with a two-week interval in between her two readings. A computer-generated hot spot region was considered a true-positive if it agrees with either one of the two annotation sets provided by the pathologist. While the intra-reader variability was 57%, our proposed method can correctly detect hot spots with 81% precision.

  8. Toward an accurate description of solid-state properties of superheavy elements

    Directory of Open Access Journals (Sweden)

    Schwerdtfeger Peter

    2016-01-01

    Full Text Available In the last two decades cold and hot fusion experiments lead to the production of new elements for the Periodic Table up to nuclear charge 118. Recent developments in relativistic quantum theory have made it possible to obtain accurate electronic properties for the trans-actinide elements with the aim to predict their potential chemical and physical behaviour. Here we report on first results of solid-state calculations for Og (element 118 to support future atom-at-a-time gas-phase adsorption experiments on surfaces such as gold or quartz.

  9. Non-coplanar compact configurations of nuclei and non-compound-nucleus contribution in the fusion cross section of the 12C+93Nb reaction

    Science.gov (United States)

    Chopra, Sahila; Hemdeep, Kaur, Arshdeep; Gupta, Raj K.

    2016-02-01

    decreasing function of center-of-mass energy Ec .m ., and hence belongs to the group of weakly fissioning nuclei, instead of the strongly fissioning superheavy nuclei for Φc=00 . On the other hand, with measured IMFs taken to represent the f f component, non-coplanarity simply increases the magnitude of CN survival probability Psurv, although its functional dependence on Ec .m . remains the same as for weakly fissioning nuclei. In other words, on adding the Φ degree of freedom, the inconsistent result of PCN behaving like strongly fissioning superheavy nuclei and Psurv like the weakly fissioning nuclei for Φc=00 changes to both PCN and Psurv behaving consistently like those of weakly fissioning nuclei. Thus, our calculations advocate for Φc as an important degree of freedom, like deformations of nuclei themselves.

  10. Search for long-lived superheavy eka-tungsten with radiopure ZnWO$_4$ crystal scintillator

    CERN Document Server

    Belli, P; Cappella, F; Cerulli, R; Danevich, F A; Denisov, V Yu; d'Angelo, A; Incicchitti, A; Kobychev, V V; Poda, D V; Polischuk, O G; Tretyak, V I

    2015-01-01

    The data collected with a radioactively pure ZnWO$_4$ crystal scintillator (699 g) in low background measurements during 2130 h at the underground (3600 m w.e.) Laboratori Nazionali del Gran Sasso (INFN, Italy) were used to set a limit on possible concentration of superheavy eka-W (seaborgium Sg, Z = 106) in the crystal. Assuming that one of the daughters in a chain of decays of the initial Sg nucleus decays with emission of high energy $\\alpha$ particle ($Q_\\alpha > 8$ MeV) and analyzing the high energy part of the measured $\\alpha$ spectrum, the limit N(Sg)/N(W) < 5.5 $\\times$ 10$^{-14}$ atoms/atom at 90% C.L. was obtained (for Sg half-life of 10$^9$ yr). In addition, a limit on the concentration of eka-Bi was set by analysing the data collected with a large BGO scintillation bolometer in an experiment performed by another group [L. Cardani et al., JINST 7 (2012) P10022]: N(eka-Bi)/N(Bi) < 1.1 $\\times$ 10$^{-13}$ atoms/atom with 90% C.L. Both the limits are comparable with those obtained in recent exp...

  11. Possibilities of production of transfermium nuclei in charged-particle evaporation channels

    Science.gov (United States)

    Hong, Juhee; Adamian, G. G.; Antonenko, N. V.

    2016-10-01

    The possibilities of direct production of the isotopes of transfermium nuclei Md,260259, No,261260, Lr-264261, Rf,265264, Db-268264, Sg-269266, Bh-271266, Hs-274267, and Mt-274270 in various asymmetric hot fusion-evaporation reactions are studied. The excitation functions of the formation of these isotopes in the α x n and p x n evaporation channels are predicted for the first time. The optimal reaction partners and conditions for the synthesis of new isotopes are suggested. The products of the suggested reactions can fill a gap of unknown isotopes between the isotopes of heaviest nuclei obtained in the x n evaporation channels of the cold and hot complete fusion reactions.

  12. Microscopic properties of superdeformed nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Karlsson, Lennart B

    1999-04-01

    Many high spin rotational bands in superdeformed nuclei have been found in the A 140 - 150 region, but so far no linking transitions to known normal-deformed states have been found in these nuclei. Therefore, configuration and spin assignments have to be based on indirect spectroscopic information. Identical bands were first discovered in this region of superdeformed states. At present, some identical bands have also been found at normal deformation, but such bands are more common at superdeformation. Recently lifetime measurements have given relative quadrupole moments with high accuracy. Spectroscopic quantities are calculated using the configuration constrained cranked Nilsson-Strutinsky model with the modified oscillator potential. In a statistical study the occurrence of identical bands is tested. Comparing superdeformed and normal deformed nuclei, the higher possibility for identical bands at superdeformation is understood from calculated reduced widths of the E{sub {gamma}} and J{sup (2)} distributions. The importance of high-N orbitals for identical bands is also discussed. Additivity of electric quadrupole moment contributions in the superdeformed A - 150 region is discussed with the nucleus {sup 152}Dy as a `core`. In analytic harmonic oscillator calculations, the effective electric quadrupole moment q{sub eff}, i.e. the change in the total quadrupole moment caused by the added particle, is expressed as a simple function of the single-particle mass, quadrupole moment q{sub {nu}}. Also in realistic calculations, simple relations between q{sub eff} and q{sub {nu}} can be used to estimate the total electric quadrupole moment, e.g. for the nucleus {sup 142}Sm, by adding the effect of 10 holes, to the total electric quadrupole moment of {sup 152}Dy. Furthermore, tools are given for estimating the quadrupole moment for possible configurations in the superdeformed A - 150 region. For the superdeformed region around {sup 143}Eu, configuration and spin assignments

  13. Double pion photoproduction in nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Gomez Tejedor, J.A. [Departamento de Fisica Teorica, Valencia (Spain); Vicente-Vacas, M.J. [Departamento de Fisica Teorica, Valencia (Spain); Oset, E. [Departamento de Fisica Teorica, Valencia (Spain)

    1995-06-19

    The inclusive A({gamma},{pi}{sup +}{pi}{sup -})X reaction is studied theoretically. A sizable enhancement of the cross section is found, in comparison with the scaling of the deuteron cross section ({sigma}{sub d} A/2). This enhancement is due to the modifications in the nuclear medium of the {gamma}N {yields}{pi}{pi}N amplitude and the pion dispersion relation. The enhancement is found to be bigger than the one already observed in the ({pi},{pi}{pi}) reaction in nuclei. ((orig.)).

  14. The competition between alpha decay and spontaneous fission in odd-even and odd-odd nuclei in the range 99 \\leg Z \\leg 129

    CERN Document Server

    Santhosh, K P

    2015-01-01

    The predictions on the mode of decay of the odd-even and odd-odd isotopes of heavy and superheavy nuclei with Z = 99-129, in the range 228 \\leg A \\leg 336, have been done within the Coulomb and proximity potential model for deformed nuclei (CPPMDN). A comparison of our calculated alpha half lives with the values computed using other theoretical models shows good agreement with each other. An extensive study on the spontaneous fission half lives of all the isotopes under study has been performed to identify the long-lived isotopes in the mass region. The study reveals that the alpha decay half lives and the mode of decay of the isotopes with Z = 109, 111, 113, 115 and 117, evaluated using our formalisms, agrees well with the experimental observations. As our study on the odd-even and odd-odd isotopes of Z = 99-129 predicts that, the isotopes $^{238,240-254}$99, $^{244,246-258}$101, $^{248,250,252-260,262}$103, $^{254,256,258-262,264}$105, $^{258,260,262-264,266}$107, $^{262,264,266-274}$109, $^{266,268-279}$11...

  15. Evidence of Critical Behavior in the Disassembly of Nuclei with A ~ 36

    CERN Document Server

    Ma, Y G; Hagel, K; Wang, J; Keutgen, T; Majka, Z; Murray, M; Qin, L; Smith, P; Natowitz, J B; Alfaro, R; Cibor, J; Cinausero, M; Masri, Y E; Fabris, D; Fioretto, E; Keksis, A L; Lunardon, M; Makeev, A G; Marie, N; Martin, E; Martínez-Davalos, A; Menchaca-Rocha, A; Nebbia, G; Prete, G; Rizzi, V; Ruangma, A; Shetty, D V; Souliotis, G A; Staszel, P; Veselsky, M; Viesti, G; Winchester, E M; Yennello, S J

    2004-01-01

    A wide variety of observables indicate that maximal fluctuations in the disassembly of hot nuclei with A ~ 36 occur at an excitation energy of 5.6 +- 0.5 MeV/u and temperature of 8.3 +- 0.5 MeV. Associated with this point of maximal fluctuations are a number of quantitative indicators of apparent critical behavior. The associated caloric curve does not appear to show a plateau such as that seen for heavier systems. This suggests that, in contrast to similar signals seen for apparent first order liquid-gas transitions in heavier nuclei, the observed behavior in these very light nuclei is associated with a transition much closer to the critical point.

  16. Pairing correlations in exotic nuclei

    CERN Document Server

    Sagawa, H

    2012-01-01

    The BCS and HFB theories which can accommodate the pairing correlations in the ground states of atomic nuclei are presented. As an application of the pairing theories, we investigate the spatial extension of weakly bound Ne and C isotopes by taking into account the pairing correlation with the Hartree-Fock-Bogoliubov (HFB) method and a 3-body model, respectively. We show that the odd-even staggering in the reaction cross sections of $^{30,31,32}$Ne and $^{14,15,16}$C are successfully reproduced, and thus the staggering can be attributed to the unique role of pairing correlations in nuclei far from the stability line. A correlation between a one-neutron separation energy and the anti-halo effect is demonstrated for $s$- and p-waves using the HFB wave functions. We also propose effective density-dependent pairing interactions which reproduce both the neutron-neutron ($nn$) scattering length at zero density and the neutron pairing gap in uniform matter. Then, we apply these interactions to study pairing gaps in ...

  17. Selfconsistent calculations for hyperdeformed nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Molique, H.; Dobaczewski, J.; Dudek, J.; Luo, W.D. [Universite Louis Pasteur, Strasbourg (France)

    1996-12-31

    Properties of the hyperdeformed nuclei in the A {approximately} 170 mass range are re-examined using the self-consistent Hartree-Fock method with the SOP parametrization. A comparison with the previous predictions that were based on a non-selfconsistent approach is made. The existence of the {open_quotes}hyper-deformed shell closures{close_quotes} at the proton and neutron numbers Z=70 and N=100 and their very weak dependence on the rotational frequency is suggested; the corresponding single-particle energy gaps are predicted to play a role similar to that of the Z=66 and N=86 gaps in the super-deformed nuclei of the A {approximately} 150 mass range. Selfconsistent calculations suggest also that the A {approximately} 170 hyperdeformed structures have neglegible mass asymmetry in their shapes. Very importantly for the experimental studies, both the fission barriers and the {open_quotes}inner{close_quotes} barriers (that separate the hyperdeformed structures from those with smaller deformations) are predicted to be relatively high, up to the factor of {approximately}2 higher than the corresponding ones in the {sup 152}Dy superdeformed nucleus used as a reference.

  18. Thermal instability of cell nuclei

    Science.gov (United States)

    Warmt, Enrico; Kießling, Tobias R.; Stange, Roland; Fritsch, Anatol W.; Zink, Mareike; Käs, Josef A.

    2014-07-01

    DNA is known to be a mechanically and thermally stable structure. In its double stranded form it is densely packed within the cell nucleus and is thermo-resistant up to 70\\:^\\circ {\\rm{C}}. In contrast, we found a sudden loss of cell nuclei integrity at relatively moderate temperatures ranging from 45 to 55\\:^\\circ {\\rm{C}}. In our study, suspended cells held in an optical double beam trap were heated under controlled conditions while monitoring the nuclear shape. At specific critical temperatures, an irreversible sudden shape transition of the nuclei was observed. These temperature induced transitions differ in abundance and intensity for various normal and cancerous epithelial breast cells, which clearly characterizes different cell types. Our results show that temperatures slightly higher than physiological conditions are able to induce instabilities of nuclear structures, eventually leading to cell death. This is a surprising finding since recent thermorheological cell studies have shown that cells have a lower viscosity and are thus more deformable upon temperature increase. Since the nucleus is tightly coupled to the outer cell shape via the cytoskeleton, the force propagation of nuclear reshaping to the cell membrane was investigated in combination with the application of cytoskeletal drugs.

  19. The search for super-heavy ions; La quete des noyaux super-lourds

    Energy Technology Data Exchange (ETDEWEB)

    Grevy, St. [Grand Accelerateur National d' Ions Lourds (GANIL-LPC), IN2P3 - CNRS / Ensicaen et Universite, 14 - Caen (France); Stodel, Ch. [Grand Accelerateur National d' Ions Lourds (GANIL), CEA-CNRS-IN2P3, 14 - Caen (France)

    2003-07-01

    The authors present the search for heavy nuclei, they briefly draw a historical review of the production of heavy isotopes and then describe the means and possibilities the French GANIL (national great accelerator of heavy ions) facility offers. The different steps of the experimental process are described: production, selection, detection and identification. The production cross-sections are so weak that every parameter involved in the production process has to be optimized. It appears that the limit of our technological knowledge has been reached and unless an important technical step forward it seems impossible to go down below the pico-barn (10{sup -12}*10{sup -24} cm{sup 2}) for production cross-sections. The 2 remaining ways to improve the situation are: 1) to increase the intensity of the incident particle beam (today we have < 10{sup 13} pps), this implies that an important development about accelerators and ion sources has to be achieved, 2) the other way is to use radioactive ion beams, the excess of neutrons of the incident ion gives a better production rate and will allow us to reach the neutron-rich part of the stability island. (A.C.)

  20. Excited nuclei in neutron star crusts

    CERN Document Server

    Takibayev, Nurgali; Nasirova, Diana

    2012-01-01

    The paper considers the chains of successive electron capture reactions by nuclei of the iron group which take place in the crystal structures of neutron star envelopes. It is shown that as a result of such reactions the daughter nuclei in excited states accumulate within certain layers of neutron star crusts. The phonon model of interactions is proposed between the excited nuclei in the crystalline structure, as well as formation of highly excited nuclear states which emit neutrons and higher energy photons.

  1. Review of metastable states in heavy nuclei

    Science.gov (United States)

    Dracoulis, G. D.; Walker, P. M.; Kondev, F. G.

    2016-07-01

    The structure of nuclear isomeric states is reviewed in the context of their role in contemporary nuclear physics research. Emphasis is given to high-spin isomers in heavy nuclei, with A≳ 150 . The possibility to exploit isomers to study some of the most exotic nuclei is a recurring theme. In spherical nuclei, the role of octupole collectivity is discussed in detail, while in deformed nuclei the limitations of the K quantum number are addressed. Isomer targets and isomer beams are considered, along with applications related to energy storage, astrophysics, medicine, and experimental advances.

  2. Shell model based reaction rates for rp-process nuclei in the mass range A=44-63

    CERN Document Server

    Fisker, J L; Görres, J; Langanke, K; Martínez-Pinedo, G; Wiescher, M C

    2001-01-01

    We have used large-scale shell-model diagonalization calculations to determine the level spectra, proton spectroscopic factors, and electromagnetic transition probabilities for proton rich nuclei in the mass range A=44-63. Based on these results and the available experimental data, we calculated the resonances for proton capture reactions on neutron deficient nuclei in this mass range. We also calculated the direct capture processes on these nuclei in the framework of a Woods-Saxon potential model. Taking into account both resonant and direct contributions, we determined the ground-state proton capture reaction rates for these nuclei under hot hydrogen burning conditions for temperatures between 10 sup 8 and 10 sup 1 sup 0 K. The calculated compound-nucleus level properties and the reaction rates are presented here; the rates are also available in computer-readable format from the authors.

  3. Production and decay of the heaviest odd-Z nuclei in the 249Bk + 48Ca reaction

    Science.gov (United States)

    Oganessian, Yu Ts; Abdullin, F. Sh; Alexander, C.; Binder, J.; Boll, R. A.; Dmitriev, S. N.; Ezold, J.; Felker, K.; Gostic, J. M.; Grzywacz, R. K.; Hamilton, J. H.; Henderson, R. A.; Itkis, M. G.; Miernik, K.; Miller, D.; Moody, K. J.; Polyakov, A. N.; Ramayya, A. V.; Roberto, J. B.; Ryabinin, M. A.; Rykaczewski, K. P.; Sagaidak, R. N.; Shaughnessy, D. A.; Shirokovsky, I. V.; Shumeiko, M. V.; Stoyer, M. A.; Stoyer, N. J.; Subbotin, V. G.; Sukhov, A. M.; Tsyganov, Yu S.; Utyonkov, V. K.; Voinov, A. A.; Vostokin, G. K.

    2015-02-01

    The reaction of 249Bk with 48Ca has been investigated with an aim of synthesizing and studying the decay properties of isotopes of the new element 117. The experiments were performed at five projectile energies (in two runs, in 2009-2010 and 2012) and with a total beam dose of 48Ca ions of about 9x1019 The experiments yielded data on a-decay characteristics and excitation functions of the produced nuclei that establish these to be 293117 and 294117 - the products of the 4n- and 3n-evaporation channels, respectively. In total, we have observed 20 decay chains of Z=117 nuclides. The cross sections were measured to be 1.1 pb for the 3n and 2.4 pb for the 4n-reaction channel. The new 289115 events, populated by α decay of 117, demonstrate the same decay properties as those observed for 115 produced in the 243Am(48Ca,2n) reaction thus providing cross-bombardment evidence. In addition, a single decay of 294118 was observed from the reaction with 249Cf - a result of the in-growth of 249Cf in the 249Bk target. The observed decay chain of 294118 is in good agreement with decay properties obtained in 2002-2005 in the experiments with the reaction 249Cf(48Ca,3n)294118. The energies and half-lives of the odd-Z isotopes observed in the 117 decay chains together with the results obtained for lower-Z superheavy nuclei demonstrate enhancement of nuclear stability with increasing neutron number towards the predicted new magic number N=184.

  4. Behavior of the Lyapunov Exponent and Phase Transition in Nuclei

    Institute of Scientific and Technical Information of China (English)

    WANG Nan; WU Xi-Zhen; LI Zhu-Xia; WANG Ning; ZHUO Yi-Zhong; SUN Xiu-Quan

    2000-01-01

    Based on the quantum molecular dynamics model, we investigate the dynamical behaviors of the excited nuclear system to simulate the latter stage of heavy ion reactions, which associate with a liquid-gas phase transition. We try to search a microscopic way to describe the phase transition in realnuclei. The Lyapunov exponent is employed and examined for our purpose. We find out that the Lyapunov exponent is one of good microscopic quantities to describe the phase transition in hot nuclei. Coulomb potential and the finite size effect may give a strong influence on the critical temperature. However, the collision term plays a minor role in the process of the liquid-gas phase transition in finite systems.

  5. Cavitation Nuclei: Experiments and Theory

    DEFF Research Database (Denmark)

    Mørch, Knud Aage

    2009-01-01

    The Swedish astrophysicist and Nobel Prize winner Hannes Alfven said: Theories come and go - the experiment is here forever. Often a theory, which we set up to describe an observed physical phenomenon, suffers from the lack of knowledge of decisive parameters, and therefore at best the theory...... becomes insufficient. Contrary, the experiment always reveals nature itself, though at prevailing experimental conditions. With essential parameters being out of control and even maybe unidentified, apparently similar experiments may deviate way beyond our expectations. However, these discrepancies offer...... us a chance to reflect on the character of the unknown parameters. In this way non-concordant experimental results may hold the key to the development of better theories - and to new experiments for the testing of their validity. Cavitation and cavitation nuclei are phenomena of that character....

  6. CAVITATION NUCLEI: EXPERIMENTS AND THEORY

    Institute of Scientific and Technical Information of China (English)

    MфRCH K. A.

    2009-01-01

    The Swedish astrophysicist and Nobel Prize winner Hannes Alfvén said: Theories come and go ─ the experiment is here forever. Often a theory, which we set up to describe an observed physical phenomenon, suffers from the lack of knowledge of decisive parameters, and therefore at best the theory becomes insufficient. Contrary, the experiment always reveals nature itself, though at prevailing experimental conditions. With essential parameters being out of control and even maybe unidentified, apparently similar experiments may deviate way beyond our expectations. However, these discrepancies offer us a chance to reflect on the character of the unknown parameters. In this way non-concordant experimental results may hold the key to the development of better theories – and to new experiments for the testing of their validity. Cavitation and cavitation nuclei are phenomena of that character.

  7. Inclusive breakup of Borromean nuclei

    CERN Document Server

    Hussein, Mahir S; Frederico, Tobias

    2016-01-01

    We derive the inclusive breakup cross section of a three-fragment projectile nuclei, $a = b +x_1 + x_2$, in the spectator model. The resulting four-body cross section for observing $b$, is composed of the elastic breakup cross section which contains information about the correlation between the two participant fragments, and the inclusive non-elastic breakup cross section. This latter cross section is found to be a non-trivial four-body generalization of the Austern formula \\cite{Austern1987}, which is proportional to a matrix element of the form, $\\langle\\hat{\\rho}_{{x_1},{x_2}}\\left|\\left[W_{{x_1}} + W_{{x_2}} + W_{3B}\\right]\\right|\\hat{\\rho}_{{x_1}, {x_2}}\\rangle$. The new feature here is the three-body absorption, represented by the imaginary potential, $W_{3B}$. We analyze this type of absorption and supply ideas of how to calculate its contribution.

  8. Formation of $\\phi$ mesic nuclei

    CERN Document Server

    Yamagata-Sekihara, J; Vacas, M J Vicente; Hirenzaki, S

    2010-01-01

    We study the structure and formation of the $\\phi$ mesic nuclei to investigate the in-medium modification of the $\\phi$-meson spectral function at finite density. We consider (${\\bar p},\\phi$), ($\\gamma,p$) and ($\\pi^-,n$) reactions to produce a $\\phi$-meson inside the nucleus and evaluate the effects of its medium modifications to the reaction cross sections. We also estimate the consequences of the uncertainties of the ${\\bar K}$ selfenergy in medium to the $\\phi$-nucleus interaction. We find that it may be possible to see a peak structure in the reaction spectra for the strong attractive potential cases. On the other hand, for strong absorptive interaction cases with relatively weak attractions, it is very difficult to observe clear peaks and we may need to know the spectrum shape in a wide energy region to deduce the properties of $\\phi$.

  9. Quasifree kaon photoproduction on nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Frank Lee; T. MART; Cornelius Bennhold; Lester Wright

    2001-12-01

    Investigations of the quasifree reaction A({gamma}, K Y)B are presented in the distorted wave impulse approximation (DWIA). For this purpose, we present a revised tree-level model of elementary kaon photoproduction that incorporates hadronic form factors consistent with gauge invariance, uses SU(3) values for the Born couplings and uses resonances consistent with multi-channel analyses. The potential of exclusive quasifree kaon photoproduction on nuclei to reveal details of the hyperon-nucleus interaction is examined. Detailed predictions for the coincidence cross section, the photon asymmetry, and the hyperon polarization and their sensitivities to the ingredients of the model are obtained for all six production channels. Under selected kinematics these observables are found to be sensitive to the hyperon-nucleus final state interaction. Some polarization observables are found to be insensitive to distortion effects, making them ideal tools to search for possible medium modifications of the elementary amplitude.

  10. Hot plasma dielectric tensor

    NARCIS (Netherlands)

    Westerhof, E.

    1996-01-01

    The hot plasma dielectric tensor is discussed in its various approximations. Collisionless cyclotron resonant damping and ion/electron Bernstein waves are discussed to exemplify the significance of a kinetic description of plasma waves.

  11. Isovector multiphonon excitations in near spherical nuclei

    CERN Document Server

    Smirnova, N A; Pietralla, N; Van Isacker, P; Isacker, Piet Van; Mizusaki, Takahiro; Pietralla, Norbert; Smirnova, Nadya A.

    2000-01-01

    The lowest isoscalar and isovector quadrupole and octupole excitations in near spherical nuclei are studied within the the proton-neutron version of the interacting boson model including quadrupole and octupole bosons (sdf-IBM-2). The main decay modes of these states in near spherical nuclei are discussed.

  12. Partial Dynamical Symmetry in Deformed Nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Leviatan, A. [Racah Institute of Physics, The Hebrew University, Jerusalem 91904 (Israel)

    1996-07-01

    We discuss the notion of partial dynamical symmetry in relation to nuclear spectroscopy. Explicit forms of Hamiltonians with partial SU(3) symmetry are presented in the framework of the interacting boson model of nuclei. An analysis of the resulting spectrum and electromagnetic transitions demonstrates the relevance of such partial symmetry to the spectroscopy of axially deformed nuclei. {copyright} {ital 1996 The American Physical Society.}

  13. Partial dynamical symmetry in deformed nuclei

    CERN Document Server

    Leviatan, A

    1996-01-01

    We discuss the notion of partial dynamical symmetry in relation to nuclear spectroscopy. Explicit forms of Hamiltonians with partial SU(3) symmetry are presented in the framework of the interacting boson model of nuclei. An analysis of the resulting spectrum and electromagnetic transitions demonstrates the relevance of such partial symmetry to the spectroscopy of axially deformed nuclei.

  14. Positron production in collision of heavy nuclei

    CERN Document Server

    Khriplovich, I B

    2016-01-01

    We consider the electromagnetic production of positron in collision of slow heavy nuclei, with the simultaneously produced electron captured by one of the nuclei. The cross-section of the discussed process exceeds essentially the cross-section of $e^+e^-$ production.

  15. RFP for the Comet Nuclei Tour (CONTOUR)

    DEFF Research Database (Denmark)

    Jørgensen, John Leif; Madsen, Peter Buch; Betto, Maurizio

    1999-01-01

    This document describes the ASC Star Tracker (performance, functionality, requirements etc.) to The Johns Hopkins University - Applied Physics Laboratory for their Comet Nuclei TOUR (CONTOUR) Program.......This document describes the ASC Star Tracker (performance, functionality, requirements etc.) to The Johns Hopkins University - Applied Physics Laboratory for their Comet Nuclei TOUR (CONTOUR) Program....

  16. Towards the exact calculation of medium nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Gandolfi, Stefano [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Carlson, Joseph Allen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lonardoni, Diego [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wang, Xiaobao [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-12-19

    The prediction of the structure of light and medium nuclei is crucial to test our knowledge of nuclear interactions. The calculation of the nuclei from two- and three-nucleon interactions obtained from rst principle is, however, one of the most challenging problems for many-body nuclear physics.

  17. Variation of hadron masses in finite nuclei

    CERN Document Server

    Saitô, K; Tsushima, K; Saito, Koichi; Thomas, Anthony W.; Tsushima, Kazuo

    1997-01-01

    Using a self-consistent, Hartree description for both infinite nuclear matter and finite nuclei based on a relativistic quark model (the quark-meson coupling model), we investigate the variation of the masses of the non-strange vector mesons, the hyperons and the nucleon in infinite nuclear matter and in finite nuclei.

  18. Energy Radiation of the Active Galactic Nuclei

    Institute of Scientific and Technical Information of China (English)

    TANG Zhi-Ming; WANG Yong-Jiu

    2004-01-01

    In the Hellings-Nordtvedt theory, we obtain some expressions of energy radiation and mass defect effect for a kind of the active galactic nuclei, which is meaningful to calculating the energy radiation in the procession of forming this kind of celestial bodies. This calculation can give some interpretation for energy source of the jet from the active galactic nuclei.

  19. Total Nuclear Reaction Cross Section Induced by Halo Nuclei and Stable Nuclei

    Institute of Scientific and Technical Information of China (English)

    GUO Wen-Jun; JIANG Huan-Qing; LIU Jian-Ye; ZUO Wei; REN Zhong-Zhou; LEE Xi-Guo

    2003-01-01

    We develop a method for calculation of the total reaction cross sections induced by the halo nuclei and stable. nuclei. This approach is based on the Glauber theory, which is valid for nuclear reactions at high energies. It is extended for nuclear reactions at low energies and intermediate energies by including both the quantum correction and Coulomb correction under the assumption of the effective nuclear density distribution. The calculated results of the total reaction cross section induced by stable nuclei agree well with 30 experimental data within 10 percent accuracy. The comparison between the numerical results and 20 experimental data for the total nuclear reaction cross section induced by the neutron halo nuclei and the proton halo nuclei indicates a satisfactory agreement after considering the halo structure of these nuclei, which implies quite different mean fields for the nuclear reactions induced by halo nuclei and stable nuclei. The halo nucleon distributions and the root-mean-square radii of these nuclei can be extracted from the above comparison based on the improved Glauber model, which indicates clearly the halo structures of these nuclei. Especially,it is clear to see that the medium correction of the nucleon-nucleon collision has little effect on the total reaction cross sections induced by the halo nuclei due to the very weak binding and the very extended density distribution.

  20. Total Nuclear Reaction Cross Section Induced by Halo Nuclei and Stable Nuclei

    Institute of Scientific and Technical Information of China (English)

    GUOWen-Jun; JIANGHuan-Qing; LIUJian-Ye; ZUOWei; RENZhong-Zhou; LEEXi-Guo

    2003-01-01

    We develop a method for calculation of the total reaction cross sections induced by the halo nuclei and stable nuclei. This approach is based on the Glauber theory, which is valid for nuclear reactions at high energies. It is extended for nuclear reactions at low energies and intermediate energies by including both the quantum correction and Coulomb correction under the assumption of the effective nuclear density distribution. The calculated results of the total reaction cross section induced by stable nuclei agree well with 30 experimental data within 10 percent accuracy.The comparison between the numerical results and 20 experimental data for the total nuclear reaction cross section induced by the neutron halo nuclei and the proton halo nuclei indicates a satisfactory agreement after considering the halo structure of these nuclei, which implies quite digerent mean fields for the nuclear reactions induced by halo nuclei and stable nuclei. The halo nucleon distributions and the root-mean-square radii of these nuclei can be extracted from the above comparison based on the improved Glauber model, which indicates clearly the halo structures of these nuclei. Especially,it is clear to see that the medium correction of the nucleon-nucleon collision has little effect on the total reaction cross sections, induced by the halo nuclei due to the very weak binding and the very extended density distribution.

  1. Chemical complexity in galactic nuclei

    Science.gov (United States)

    Martin-Pintado, Jesus

    2007-12-01

    In recent years our knowledge of the chemical complexity in the nuclei of galaxies has dramatically changed. Recent observations of the nucleus of the Milky Way, of the starburst galaxy NGC253 and of the ultraluminous infrared galaxy (ULIRG) Arp220 have shown large abundance of complex organic molecules believed to be formed on grains. The Galactic center appears to be the largest repository of complex organic molecule like aldehydes and alcohols in the galaxy. We also measure large abundance of methanol in starburst galaxies and in ULIRGs suggesting that complex organic molecules are also efficiently produced in the central region of galaxies with strong star formation activity. From the systematic observational studies of molecular abundance in regions dominated by different heating processes like shocks, UV radiation, X-rays and cosmic rays in the center of the Milky Way, we are opening the possibility of using chemistry as a diagnostic tool to study the highly obscured regions of galactic centers. The templates found in the nucleus of the Milky Way will be used to establish the main mechanisms driving the heating and the chemistry of the molecular clouds in galaxies with different type of activity. The role of grain chemistry in the chemical complexity observed in the center of galaxies will be also briefly discussed.

  2. Molecular outflows in starburst nuclei

    CERN Document Server

    Roy, Arpita; Sharma, Prateek; Shchekinov, Yuri

    2016-01-01

    Recent observations have detected molecular outflows in a few nearby starburst nuclei. We discuss the physical processes at work in such an environment in order to outline a scenario that can explain the observed parameters of the phenomenon, such as the molecular mass, speed and size of the outflows. We show that outflows triggered by OB associations, with $N_{OB}\\ge 10^5$ (corresponding to a star formation rate (SFR)$\\ge 1$ M$_{\\odot}$ yr$^{-1}$ in the nuclear region), in a stratified disk with mid-plane density $n_0\\sim 200\\hbox{--}1000$ cm$^{-3}$ and scale height $z_0\\ge 200 (n_0/10^2 \\, {\\rm cm}^{-3})^{-3/5}$ pc, can form molecules in a cool dense and expanding shell. The associated molecular mass is $\\ge 10^7$ M$_\\odot$ at a distance of a few hundred pc, with a speed of several tens of km s$^{-1}$. We show that a SFR surface density of $10 \\le \\Sigma_{SFR} \\le 50$ M$_\\odot$ yr$^{-1}$ kpc$^{-2}$ favours the production of molecular outflows, consistent with observed values.

  3. The morphology of cometary nuclei

    Science.gov (United States)

    Keller, H. U.; Jorda, L.

    comets display residual activity or clouds of dust grains around their nuclei. Taking the residual signal into account (mostly using simple models for the brightness distribution) the size estimates of the nuclei could be improved. The (nuclear) magnitude of a comet depends on the product of its albedo and cross-section. Only in a few cases could the albedo and size of a cometary nucleus be separated by additional observation of its thermal emission at infrared wavelengths. By comparison with outer Solar System asteroids Cruikshank et al. (1985) derived a surprisingly low albedo of about 0.04. A value in clear contradiction to the perception of an icy surface but fully confirmed by the first resolved images of a cometary nucleus during the flybys of the Vega and Giotto spacecraft of comet Halley (Sagdeev et al. 1986, Keller et al. 1986). The improvements of radar techniques led to the detection of reflected signals and finally to the derivation of nuclear dimensions and rotation rates. The observations, however, are also model dependent (rotation and size are similarly interwoven as are albedo and size) and sensitive to large dust grains in the vicinity of a nucleus. As an example, Kamoun et al. (1982) determined the radius of comet Encke to 1.5 (2.3, 1.0) km using the spin axis determination of Whipple and Sekanina (1979). The superb spatial resolution of the Hubble Space Telescope (HST) is not quite sufficient to resolve a cometary nucleus. The intensity distribution of the inner coma, however, can be observed and extrapolated toward the nucleus based on models of the dust distribution. If this contribution is subtracted from the central brightness the signal of the nucleus can be derived and hence its product of albedo times cross-section (Lamy and Toth 1995, Rembor 1998, Keller and Rembor 1998; Section 4.3). It has become clear that cometary nuclei are dark, small, often irregular bodies with dimensions ranging from about a kilometre (comet Wirtanen, the target of

  4. IR Hot Wave

    Energy Technology Data Exchange (ETDEWEB)

    Graham, T. B.

    2010-04-01

    The IR Hot Wave{trademark} furnace is a breakthrough heat treatment system for manufacturing metal components. Near-infrared (IR) radiant energy combines with IR convective heating for heat treating. Heat treatment is an essential process in the manufacture of most components. The controlled heating and cooling of a metal or metal alloy alters its physical, mechanical, and sometimes chemical properties without changing the object's shape. The IR Hot Wave{trademark} furnace offers the simplest, quickest, most efficient, and cost-effective heat treatment option for metals and metal alloys. Compared with other heat treatment alternatives, the IR Hot Wave{trademark} system: (1) is 3 to 15 times faster; (2) is 2 to 3 times more energy efficient; (3) is 20% to 50% more cost-effective; (4) has a {+-}1 C thermal profile compared to a {+-}10 C thermal profile for conventional gas furnaces; and (5) has a 25% to 50% smaller footprint.

  5. Hot Air Engines

    Directory of Open Access Journals (Sweden)

    P. Stouffs

    2011-01-01

    Full Text Available Invented in 1816, the hot-air engines have known significant commercial success in the nineteenth century, before falling into disuse. Nowadays they enjoy a renewed interest for some specific applications. The "hot-air engines" family is made up of two groups: Stirling engines and Ericsson engines. The operating principle of Stirling and Ericsson engines, their troubled history, their advantages and their niche applications are briefly presented, especially in the field of micro-combined heat and power, solar energy conversion and biomass energy conversion. The design of an open cycle Ericsson engine for solar application is proposed. A first prototype of the hot part of the engine has been built and tested. Experimental results are presented.

  6. Deep inelastic scattering on asymmetric nuclei

    Science.gov (United States)

    Saito, K.; Boros, C.; Tsushima, K.; Bissey, F.; Afnan, I. R.; Thomas, A. W.

    2000-11-01

    We study deep inelastic scattering on isospin asymmetric nuclei. In particular, the difference of the nuclear structure functions and the Gottfried sum rule for the lightest mirror nuclei, 3He and 3H, are investigated. It is found that such systems can provide significant information on charge symmetry breaking and flavor asymmetry in the nuclear medium. Furthermore, we propose a new method to extract the neutron structure function from radioactive isotopes far from the line of stability. We also discuss the flavor asymmetry in the Drell-Yan process with isospin asymmetric nuclei.

  7. Coupled-cluster computations of atomic nuclei

    CERN Document Server

    Hagen, G; Hjorth-Jensen, M; Dean, D J

    2013-01-01

    In the past decade, coupled-cluster theory has seen a renaissance in nuclear physics, with computations of neutron-rich and medium-mass nuclei. The method is efficient for nuclei with product-state references, and it describes many aspects of weakly bound and unbound nuclei. This report reviews the technical and conceptual developments of this method in nuclear physics, and the results of coupled-cluster calculations for nucleonic matter, and for exotic isotopes of helium, oxygen, calcium, and some of their neighbors.

  8. Critical-Point Structure in Finite Nuclei

    CERN Document Server

    Leviatan, A

    2006-01-01

    Properties of quantum shape-phase transitions in finite nuclei are considered in the framework of the interacting boson model. Special emphasis is paid to the dynamics at the critical-point of a general first-order phase transition.

  9. Few-Body Universality in Halo Nuclei

    Directory of Open Access Journals (Sweden)

    Hammer H.-W.

    2016-01-01

    Full Text Available Few-body systems with resonant S-wave interactions show universal properties which are independent of the interaction at short distances. These properties include a geometric spectrum of three- and higher-body bound states and universal correlations between few-body observables. They can be observed on a wide range of scales from hadrons and nuclei to ultracold atoms. In this contribution, we focus on few-body universality in halo nuclei which can be considered as effective few-body systems consisting of halo nucleons and a core. This concept provides a unifying framework for halo nuclei with calculable corrections. Recent progress in this field with an emphasis on the possibility of finding Efimov states in halo nuclei is discussed.

  10. Few-Body Universality in Halo Nuclei

    Science.gov (United States)

    Hammer, H.-W.

    2016-03-01

    Few-body systems with resonant S-wave interactions show universal properties which are independent of the interaction at short distances. These properties include a geometric spectrum of three- and higher-body bound states and universal correlations between few-body observables. They can be observed on a wide range of scales from hadrons and nuclei to ultracold atoms. In this contribution, we focus on few-body universality in halo nuclei which can be considered as effective few-body systems consisting of halo nucleons and a core. This concept provides a unifying framework for halo nuclei with calculable corrections. Recent progress in this field with an emphasis on the possibility of finding Efimov states in halo nuclei is discussed.

  11. Quantum Monte Carlo Calculations of Light Nuclei

    CERN Document Server

    Pieper, Steven C

    2007-01-01

    During the last 15 years, there has been much progress in defining the nuclear Hamiltonian and applying quantum Monte Carlo methods to the calculation of light nuclei. I describe both aspects of this work and some recent results.

  12. On The Structure of A=3 Nuclei

    CERN Document Server

    Abbas, Syed Afsar

    2011-01-01

    The hole in the charge distribution of $^3{\\text He}$ is a major problem in A=3 nuclei. The canonical wavefucntion of A=3 nuclei which does well for electromagnetic properties of A=3 nuclei fails to produce the hole in A=3 nuclei. The hole is normally assumed to arise from explicit quark degree of freedom. Very often quark degrees of freedom are imposed to propose a different short range part of the wavefunction for A=3 to explain the hole in $^3{\\text He}$. So an hybrid model with nucleonic degree of freedom in outer part and quark degrees of freedom in the inner part of the nucleus have been invoked to understand the above problem. Here we present a different picture with a new wavefunction working at short range within nucleonic degrees of freedom itself. So the above problem is explained here based entirely on the nucleonic degree of freedom only.

  13. Ultrasonic Hot Embossing

    Directory of Open Access Journals (Sweden)

    Werner Karl Schomburg

    2011-05-01

    Full Text Available Ultrasonic hot embossing is a new process for fast and low-cost production of micro systems from polymer. Investment costs are on the order of 20.000 € and cycle times are a few seconds. Microstructures are fabricated on polymer foils and can be combined to three-dimensional systems by ultrasonic welding.

  14. What's Hot? What's Not?

    Science.gov (United States)

    Buczynski, Sandy

    2006-01-01

    When Goldilocks finds three bowls of porridge at different temperatures in the three bears' house, she accurately assesses the situation and comes up with one of the most recognizable lines in children's literature," This porridge is too hot; this porridge is too cold; aahh, this porridge is just right!" Goldilocks' famous line is a perfect…

  15. Hot house bad house

    OpenAIRE

    Azzopardi, Shaun

    2014-01-01

    Shaun Azzopardi met up with a team of researchers led by Eur. Ing. Charles Yousif to take the concrete block to the next level. It is more exciting than it sounds. Photography by Dr Edward Duca. http://www.um.edu.mt/think/hot-house-bad-house/

  16. Fending Off Hot Money

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Amid uncertainties about the amount of hot money,the government strives to curb the harmful capital The benchmark Shanghai Composite Index was plagued by dips, climbs and dives as the stock market slumped from 3,186 to 2,838 points

  17. E1 strength in N = 82 nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Hartmann, T.; Volz, S.; Babilon, M.; Mohr, P.; Vogt, K.; Zilges, A

    2003-05-19

    Recently the importance of small contributions of electric dipole strength near the particle threshold to the production rates of atomic nuclei has become evident. Prior estimates concentrated on the Giant Dipole Resonance (GDR) which dominates photoabsorption in all nuclei. Extrapolations to smaller excitation energies were assumed to be sufficiently reliable. However, new measurements reveal that collective E1 strength can be found in the threshold region.

  18. Statistical Properties of Quantum Spectra in Nuclei

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Some aspects of quantum chaos in a finite system have been studied based on the analysis of statistical behaviors of quantum spectrum in nuclei. The experiment data show the transition from order to chaos with increasing excitation energy in spherical nuclei. The dependence of the order to chaos transition on nuclear deformation and nuclear rotating is described. The influence of pairing effect on the order to chaos transition is also discussed. Some important experiment phenomena in nuclear

  19. Shell structure of nuclei far from stability

    CERN Document Server

    Grawe, H

    2001-01-01

    The experimental status of shell structure studies in medium-heavy nuclei far off the line of beta-stability is reviewed. Experimental techniques, signatures for shell closure and expectations for future investigations are discussed for the key regions around sup 4 sup 8 sup , sup 5 sup 6 Ni, sup 1 sup 0 sup 0 Sn for proton rich nuclei and the neutron-rich N=20 isotones, Ca, Ni and Sn isotopes.

  20. Masses of nuclei close to the dripline

    CERN Document Server

    Herfurth, F; Beck, D; Blaum, K; Bollen, G; Kellerbauer, A G; Kluge, H J; Lunney, M D; Rodríguez, D; Schwarz, S; Sikler, G; Weber, C

    2003-01-01

    Mass measurements of radioactive nuclides are one of the cornerstones of our understanding of the nucleus. The Penning trap spectrometer ISOLTRAP performs direct mass measurements far away from the valley of stability, as well as high-precision measurements of key nuclei to anchor long decay chains. Both schemes provide valuable information on the dripline itself and on nuclei in its close vicinity. (10 refs) .

  1. Realistic level density calculation for heavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Cerf, N. [Institut de Physique Nucleaire, Orsay (France); Pichon, B. [Observatoire de Paris, Meudon (France); Rayet, M.; Arnould, M. [Institut d`Astronomie et d`Astrophysique, Bruxelles (Belgium)

    1994-12-31

    A microscopic calculation of the level density is performed, based on a combinatorial evaluation using a realistic single-particle level scheme. This calculation relies on a fast Monte Carlo algorithm, allowing to consider heavy nuclei (i.e., large shell model spaces) which could not be treated previously in combinatorial approaches. An exhaustive comparison of the predicted neutron s-wave resonance spacings with experimental data for a wide range of nuclei is presented.

  2. Quark Degrees of Freedom in Finite Nuclei

    CERN Document Server

    Tsushima, K; Thomas, A W; Tsushima, Kazuo; Saito, Koichi; Thomas, Anthony W.

    1996-01-01

    Properties of finite nuclei are investigated based on relativistic Hartree equations which have been derived from a relativistic quark model of the structure of bound nucleons. Nucleons are assumed to interact through the (self-consistent) exchange of scalar ($\\sigma$) and vector ($\\omega$ and and the rms charge radius in $^{40}$Ca. Calculated properties of static, closed-shell nuclei, as well as symmetric nuclear matter are compared with experimental data and with the results of Quantum Hadrodynamics (QHD).

  3. Stability of superheavy elements around Z=120 probed by the study of their fission time obtained by the crystal blocking method; Stabilite d'elements superlourds au voisinage de Z=120 testee par l'etude de leurs temps de fission deduits par la methode du blocage cristallin

    Energy Technology Data Exchange (ETDEWEB)

    Laget, M

    2007-10-15

    While the existence of an island of stability beyond Z=110 is theoretically acquired, the location of this island ranges from Z=114 to Z=126 depending on models. In this work, the stability of super-heavy nuclei is probed through the study of their fission time. The chosen experimental method, the crystal blocking method, is sensitive to the presence of possible long time components in the fission time distribution which indicates a fission mechanism occurring after the formation of a compound nucleus. The blocking dips were therefore constituted for the various products of the reaction U{sup 238} + Ni (6.6 MeV/A) {yields} 120, the experimental set-up allowing us to clearly identify and select the reaction mechanisms. The comparison of the blocking dip constituted for quasi-elastic scattering events with the one obtained for the fission fragments of a Z=120, combined with the study of kinematical properties of these fission fragments, give evidences of the existence of very long fission times (> 10{sup -18} s) only compatible with a fusion-fission mechanism implying a non vanishing fission barrier height for Z=120. The second part outlines microscopic calculations of fission barrier heights, carried out in the framework of the finite temperature of the Hartree-Fock-Bogoliubov (HFB) theory. Because of the progressive vanishing of the pairing correlation with T, which happens differently at the ground state and at the top of the barrier, B{sub f} first grows until T {approx_equal} 0.8 MeV before dropping with T owing to shell-effects damping with temperature. (author)

  4. Hot Fuel Examination Facility (HFEF)

    Data.gov (United States)

    Federal Laboratory Consortium — The Hot Fuel Examination Facility (HFEF) is one of the largest hot cells dedicated to radioactive materials research at Idaho National Laboratory (INL). The nation's...

  5. What Kinds of Accretion Disks Are There in the Nuclei of Radio Galaxies?

    CERN Document Server

    Kaburaki, Osamu; Tamura, Naoya; Wajima, Kiyoaki

    2010-01-01

    It seems to be a widely accepted opinion that the types of accretion disks (or flows) generally realized in the nuclei of radio galaxies and in further lower mass-accretion rate nuclei are inner, hot, optically thin, radiatively inefficient accretion flows (RIAFs) surrounded by outer, cool, optically thick, standard type accretion disks. However, observational evidence for the existence of such outer cool disks in these nuclei is rather poor. Instead, recent observations sometimes suggest the existence of inner cool disks of non-standard type, which develop in the region very close to their central black holes. Taking NGC 4261 as a typical example of such light eating nuclei, for which both flux data ranging from radio to X-ray and data for the counterjet occultation are available, we examine the plausibility of such a picture for the accretion states as mentioned above, based on model predictions. It is shown that the explanation of the gap seen in the counterjet emission in terms of the free-free absorption...

  6. What Is Hot Yoga (Bikram)?

    Science.gov (United States)

    Healthy Lifestyle Consumer health What is hot yoga? Answers from Edward R. Laskowski, M.D. Hot yoga is a vigorous form of yoga performed in a studio ... you check with your doctor before trying hot yoga if you have any health concerns. If you have heart disease, problems with ...

  7. Evidence for a long-lived superheavy nucleus with atomic mass number A=292 and atomic number Z=~122 in natural Th

    CERN Document Server

    Marinov, A; Kolb, D; Pape, A; Kashiv, Y; Brandt, R; Gentry, R V; Miller, H W

    2008-01-01

    Evidence for the existence of a superheavy nucleus with atomic mass number A=292 and abundance (1-10)x10^(-12) relative to 232Th has been found in a study of natural Th using inductively coupled plasma-sector field mass spectrometry. The measured mass matches the predictions [1,2] for the mass of an isotope with atomic number Z=122 or a nearby element. Its estimated half-life of t1/2 >= 10^8 y suggests that a long-lived isomeric state exists in this isotope. The possibility that it might belong to a new class of long-lived high spin super- and hyperdeformed isomeric states is discussed.[3-6

  8. Properties of Z=120 nuclei and the \\alpha-decay chains of the (292,304)120 isotopes using relativistic and non-relativistic formalisms

    CERN Document Server

    Ahamad, Shakeb; Patra, S K

    2012-01-01

    The ground state and first intrinsic excited state of superheavy nuclei with Z=120 and N=160-204 are investigated using both non-relativistic Skyrme-Hartree-Fock and the axially deformed Relativistic Mean Field formalisms. We employ a simple BCS pairing approach for calculating the energy contribution from pairing interaction. The results for isotopic chain of binding energy, quadrupole deformation parameter, two neutron separation energies and some other observables are compared with the FRDM and some recent macroscopic-microscopic calculations. We predict superdeformed ground state solutions for almost all the isotopes. Considering the possibility of magic neutron number, two different mode of \\alpha-decay chains (292)120 and (304)120 are also studied within these frameworks. The Q_{\\alpha}-values and the half-life T^{\\alpha}_{1/2} for these two different mode of decay chains are compared with FRDM and recent macroscopic-microscopic calculations. The calculation is extended for the \\alpha-decay chains of 29...

  9. Discovery of Daemons Makes Power Generation by Daemon-Assisted Catalysis of Light Nuclei Fusion in a Ball Lightning a Reality

    CERN Document Server

    Drobyshevski, E M

    2004-01-01

    In 1997, we proposed a model of the ball lightning (BL) whose activity is accounted for by energy release in the fusion of light nuclei, most probably, carbon in organic fibers (Proc. ISBL 97, p.157). The fusion is provided by catalytic action of superheavy negative particles making up the Galactic Dark Matter. We called them DArk Electric Matter Objects, or daemons. The daemons are assumed to be elementary black holes (M ~ 10^-5 g) carrying a charge of up to Ze = 10e. Experiments have culminated in 2000 by the discovery of daemons. We used the two-screen scintillation technique with a scintillator ZnS(Ag). Measurements showed the daemon flux striking the Earth to be ~10^-9 cm^-2s^-1 for an object velocity of as low as ~<10-30 km/s. The half-year periodicity of the flux was revealed, which can be assigned to daemons being captured into helio- and geocentric orbits as the Solar system moves through the DM background (see astro-ph/0402367). The next step in creating a daemon-mediated BL to achieve controlled...

  10. Hot Subluminous Stars

    Science.gov (United States)

    Heber, U.

    2016-08-01

    Hot subluminous stars of spectral type B and O are core helium-burning stars at the blue end of the horizontal branch or have evolved even beyond that stage. Most hot subdwarf stars are chemically highly peculiar and provide a laboratory to study diffusion processes that cause these anomalies. The most obvious anomaly lies with helium, which may be a trace element in the atmosphere of some stars (sdB, sdO) while it may be the dominant species in others (He-sdB, He-sdO). Strikingly, the distribution in the Hertzsprung-Russell diagram of He-rich versus He-poor hot subdwarf stars of the globular clusters ω Cen and NGC 2808 differ from that of their field counterparts. The metal-abundance patterns of hot subdwarfs are typically characterized by strong deficiencies of some lighter elements as well as large enrichments of heavy elements. A large fraction of sdB stars are found in close binaries with white dwarf or very low-mass main sequence companions, which must have gone through a common-envelope (CE) phase of evolution. Because the binaries are detached they provide a clean-cut laboratory to study this important but yet poorly understood phase of stellar evolution. Hot subdwarf binaries with sufficiently massive white dwarf companions are viable candidate progenitors of type Ia supernovae both in the double degenerate as well as in the single degenerate scenario as helium donors for double detonation supernovae. The hyper-velocity He-sdO star US 708 may be the surviving donor of such a double detonation supernova. Substellar companions to sdB stars have also been found. For HW Vir systems the companion mass distribution extends from the stellar into the brown dwarf regime. A giant planet to the acoustic-mode pulsator V391 Peg was the first discovery of a planet that survived the red giant evolution of its host star. Evidence for Earth-size planets to two pulsating sdB stars have been reported and circumbinary giant planets or brown dwarfs have been found around HW

  11. The hot Hagedorn Universe

    CERN Document Server

    Rafelski, Johann

    2016-01-01

    In the context of the half-centenary of Hagedorn temperature and the statistical bootstrap model (SBM) we present a short account of how these insights coincided with the establishment of the hot big-bang model (BBM) and helped resolve some of the early philosophical difficulties. We then turn attention to the present day context and show the dominance of strong interaction quark and gluon degrees of freedom in the early stage, helping to characterize the properties of the hot Universe. We focus attention on the current experimental insights about cosmic microwave background (CMB) temperature fluctuation, and develop a much improved understanding of the neutrino freeze-out, in this way paving the path to the opening of a direct connection of quark-gluon plasma (QGP) physics in the early Universe with the QCD-lattice, and the study of the properties of QGP formed in the laboratory.

  12. The hot chocolate effect

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, Frank S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States)

    1982-05-01

    The "hot chocolate effect" was investigated quantitatively, using water. If a tall glass cylinder is filled nearly completely with water and tapped on the bottom with a softened mallet one can detect the lowest longitudinal mode of the water column, for which the height of the water column is one quarter wavelength. If the cylinder is rapidly filled with hot tap water containing dissolved air the pitch of that mode may descend by nearly three octaves during the first few seconds as the air comes out of solution and forms bubbles. Then the pitch gradually rises as the bubbles float to the top. A simple theoretical expression for the pitch ratio is derived and compared with experiment. The agreement is good to within the ten percent accuracy of the experiments.

  13. Hot chocolate effect

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, F.S.

    1982-05-01

    The ''hot chocolate effect'' was investigated quantitatively, using water. If a tall glass cylinder is filled nearly completely with water and tapped on the bottom with a softened mallet one can detect the lowest longitudinal mode of the water column, for which the height of the water column is one-quarter wavelength. If the cylinder is rapidly filled with hot tap water containing dissolved air the pitch of that mode may descend by nearly three octaves during the first few seconds as the air comes out of solution and forms bubbles. Then the pitch gradually rises as the bubbles float to the top. A simple theoretical expression for the pitch ratio is derived and compared with experiment. The agreement is good to within the 10% accuracy of the experiments.

  14. Hot Spring Metagenomics

    Directory of Open Access Journals (Sweden)

    Olalla López-López

    2013-04-01

    Full Text Available Hot springs have been investigated since the XIX century, but isolation and examination of their thermophilic microbial inhabitants did not start until the 1950s. Many thermophilic microorganisms and their viruses have since been discovered, although the real complexity of thermal communities was envisaged when research based on PCR amplification of the 16S rRNA genes arose. Thereafter, the possibility of cloning and sequencing the total environmental DNA, defined as metagenome, and the study of the genes rescued in the metagenomic libraries and assemblies made it possible to gain a more comprehensive understanding of microbial communities—their diversity, structure, the interactions existing between their components, and the factors shaping the nature of these communities. In the last decade, hot springs have been a source of thermophilic enzymes of industrial interest, encouraging further study of the poorly understood diversity of microbial life in these habitats.

  15. Peppery Hot Bean Curd

    Institute of Scientific and Technical Information of China (English)

    1997-01-01

    Peppery Hot Bean Curd is a famous dish that originated in Chengdu,Sichuan Province.Dating back to the year under the reign of Emperor Tongzhi during the Qing Dynasty(1862-1875),a woman chef named Chen created this dish.In Chinese it is called Mapo Bean Curd. Ingredients:Three pieces of bean curd,100 grams lean pork,25 grams green soy beans or garlic

  16. Hot subluminous stars

    CERN Document Server

    Heber, Ulrich

    2016-01-01

    Hot subluminous stars of spectral type B and O are core helium-burning stars at the blue end of the horizontal branch or have evolved even beyond that stage. Strikingly, the distribution in the Hertzsprung-Russell diagram of He-rich vs. He-poor hot subdwarf stars of the globular clusters omega Cen and NGC~2808 differ from that of their field counterparts. The metal-abundance patterns of hot subdwarfs are typically characterized by strong deficiencies of some lighter elements as well as large enrichments of heavy elements. A large fraction of sdB stars are found in close binaries with white dwarf or very low-mass main sequence companions, which must have gone through a common-envelope phase of evolution.They provide a clean-cut laboratory to study this important but yet purely understood phase of stellar evolution. Substellar companions to sdB stars have also been found. For HW~Vir systems the companion mass distribution extends from the stellar into the brown dwarf regime. A giant planet to the pulsator V391 ...

  17. Solar Hot Water Heater

    Science.gov (United States)

    1978-01-01

    The solar panels pictured below, mounted on a Moscow, Idaho home, are part of a domestic hot water heating system capable of providing up to 100 percent of home or small business hot water needs. Produced by Lennox Industries Inc., Marshalltown, Iowa, the panels are commercial versions of a collector co-developed by NASA. In an effort to conserve energy, NASA has installed solar collectors at a number of its own facilities and is conducting research to develop the most efficient systems. Lewis Research Center teamed with Honeywell Inc., Minneapolis, Minnesota to develop the flat plate collector shown. Key to the collector's efficiency is black chrome coating on the plate developed for use on spacecraft solar cells, the coating prevents sun heat from "reradiating," or escaping outward. The design proved the most effective heat absorber among 23 different types of collectors evaluated in a Lewis test program. The Lennox solar domestic hot water heating system has three main components: the array of collectors, a "solar module" (blue unit pictured) and a conventional water heater. A fluid-ethylene glycol and water-is circulated through the collectors to absorb solar heat. The fluid is then piped to a double-walled jacket around a water tank within the solar module.

  18. Jupiter's Hot, Mushy Moon

    Science.gov (United States)

    Taylor, G. Jeffrey

    2003-01-01

    Jupiter's moon Io is the most volcanically active body in the Solar System. Observations by instruments on the Galileo spacecraft and on telescopes atop Mauna Kea in Hawai'i indicate that lava flows on Io are surprisingly hot, over 1200 oC and possibly as much as 1300 oC; a few areas might have lava flows as hot as 1500 oC. Such high temperatures imply that the lava flows are composed of rock that formed by a very large amount of melting of Io's mantle. This has led Laszlo Keszthelyi and Alfred S. McEwen of the University of Arizona and me to reawaken an old hypothesis that suggests that the interior of Io is a partially-molten mush of crystals and magma. The idea, which had fallen out of favor for a decade or two, explains high-temperature hot spots, mountains, calderas, and volcanic plains on Io. If correct, Io gives us an opportunity to study processes that operate in huge, global magma systems, which scientists believe were important during the early history of the Moon and Earth, and possibly other planetary bodies as well. Though far from proven, the idea that Io has a ocean of mushy magma beneath its crust can be tested with measurements by future spacecraft.

  19. Electron scattering and reactions from exotic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Karataglidis, S. [University of Johannesburg, Department of Physics, Auckland Park (South Africa); University of Melbourne, School of Physics, Victoria (Australia)

    2017-04-15

    The SCRIT and FAIR/ELISe experiments are the first to attempt to measure directly electron scattering form factors from nuclei far from stability. This will give direct information for the (one-body) charge densities of those systems, about which there is little information available. The SCRIT experiment will be taking data for medium-mass exotic nuclei, while the electron-ion collider at ELISe, when constructed, will be able to measure form factors for a wide range of exotic nuclei, as available from the radioactive ion beams produced by the FAIR experiment. Other facilities are now being proposed, which will also consider electron scattering from exotic nuclei at higher energies, to study short-range correlations in exclusive reactions. This review will consider all available information concerning the current status (largely theoretical) of electron scattering from exotic nuclei and, where possible, complement such information with equivalent information concerning the neutron densities of those exotic systems, as obtained from intermediate energy proton scattering. The issue of long- and short-range correlations will be discussed, and whether extending such studies to the exotic sector will elicit new information. (orig.)

  20. Pollen grains are efficient cloud condensation nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Pope, F D, E-mail: fdp21@cam.ac.uk [Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW (United Kingdom)

    2010-10-15

    This letter presents a laboratory study investigating the ability of pollen grains to act as cloud condensation nuclei. The hygroscopicity of pollen is measured under subsaturated relative humidities using an electrodynamic balance. It is found, along with other results, that pollen exhibits bulk uptake of water under subsaturated conditions. Through the use of an environmental scanning electron microscope it was observed that the surface of pollen is wettable at high subsaturated humidities. The hygroscopic response of the pollen to subsaturated relative humidities is parametrized using {kappa}-Koehler theory and values of the parameter {kappa} for pollen are between 0.05 and 0.1. It is found that while pollen grains are only moderately hygroscopic, they can activate at critical supersaturations of 0.001% and lower, and thus pollen grains will readily act as cloud condensation nuclei. While the number density of pollen grains is too low for them to represent a significant global source of cloud condensation nuclei, the large sizes of pollen grains suggest that they will be an important source of giant cloud condensation nuclei. Low temperature work using the environmental scanning electron microscope indicated that pollen grains do not act as deposition ice nuclei at temperatures warmer than - 15 deg. C.

  1. PREFACE: Hot Quarks 2004

    Science.gov (United States)

    Antinori, Federico; Bass, Steffen A.; Bellwied, Rene; Ullrich, Thomas; Velkovska, Julia; Wiedemann, Urs

    2005-04-01

    Why another conference devoted to ultra-relativistic heavy-ion physics? As we looked around the landscape of the existing international conferences and workshops, we realized that there was not a single one tailored to the people who are most directly involved with the actual research work: students, post-docs, and junior faculty/research scientists. Of course there are schools, but that was not what we had in mind. We wanted a meeting where young researchers could come together to discuss in depth the physics that they are working on without any hindrance. The major conferences have very limited time for discussions which is often shared amongst the most established. This leaves little room for young people to ask their questions and to get the detailed feedback which they deserve and which satisfies their curiosity. A discussion-driven workshop, centering on those without whom there will be no future—that seemed like what was needed. And thus the Hot Quarks workshop was born. The aim of Hot Quarks was to enhance the direct exchange of scientific information among the younger members of the community, from both experiment and theory. Participation was by invitation only in order to emphasize the contributions from junior researchers. This approach makes the workshop unique among the many forums in the field. For young scientists it represented an opportunity for exposure that they would not have had in one of the major conferences. The hope is that this meeting has helped to stimulate the next generation of scientists in our field and, at the same time, strengthened their sense of community. It all came together from 18 24 July 2004, when the 77 participants met at The Inn at Snakedance in the Taos Ski Valley, New Mexico, USA, for the first Hot Quarks workshop. Photograph Participants gather in the sunshine at the foot of the Taos Ski Valley chairlift. By all accounts, Hot Quarks 2004 was a great success. Every participant had the opportunity to present her or

  2. The Scattering of Fast Nucleons from Nuclei

    Science.gov (United States)

    Kerman, A. K.; McManus, H.; Thaler, R. M.

    2000-04-01

    The formal theory of the scattering of high-energy nucleons by nuclei is developed in terms of the nucleon-nucleon scattering amplitude. The most important approximations necessary to make numerical calculation feasible are then examined. The optical model potential is derived on this basis and compared with the optical model parameters found from experiment. The elastic scattering and polarization of nucleons from light nuclei is predicted and compared with experiment. The effect of nuclear correlations is discussed. The polarization of inelastically scattered nucleons is discussed and predictions compared with experiments. To within the validity of the approximations the experimental data on the scattering of nucleons from nuclei at energies above ˜100 Mev appears to be consistent with the theory.

  3. The scattering of fast nucleons from nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Kerman, A. K. [Massachusetts Institute of Technology, Cambridge, Massachusetts (United States); McManus, H. [Chalk River Laboratory, Chalk River, Ontario, (Canada); Thaler, R. M. [Los Alamos Scientific Laboratory, Los Alamos, New Mexico (United States)

    2000-04-10

    The formal theory of the scattering of high-energy nucleons by nuclei is developed in terms of the nucleon nucleon scattering amplitude. The most important approximations necessary to make numerical calculation feasible are then examined. The optical model potential is derived on this basis and compared with the optical model parameters found from experiment. The elastic scattering and polarization of nucleons from light nuclei is predicted and compared with experiment. The effect of nuclear correlations is discussed. The polarization of inelastically scattered nucleons is discussed and predictions compared with experiments. To within the validity of the approximations the experimental data on the scattering of nucleons from nuclei at energies above {approx}100 Mev appears to be consistent with the theory. (c) 2000 Academic Press, Inc.

  4. Reflections on cavitation nuclei in water

    DEFF Research Database (Denmark)

    Mørch, Knud Aage

    2007-01-01

    The origin of cavitation bubbles, cavitation nuclei, has been a subject of debate since the early years of cavitation research. This paper presents an analysis of a representative selection of experimental investigations of cavitation inception and the tensile strength of water. At atmospheric...... on the surface of particles and bounding walls. Such nuclei can be related to the full range of tensile strengths measured, when differences of experimental conditions are taken into consideration. The absence or presence of contamination on surfaces, as well as the structure of the surfaces, are central...... to explaining why the tensile strength of water varies so dramatically between the experiments reported. A model for calculation of the critical pressure of skin-covered free gas bubbles as well as that of interfacial gaseous nuclei covered by a skin is presented. This model is able to bridge the apparently...

  5. Nucleon localization in light and heavy nuclei

    CERN Document Server

    Zhang, C L; Nazarewicz, W

    2016-01-01

    An electron localization measure was originally introduced to characterize chemical bond structures in molecules. Recently, a nucleon localization based on Hartree-Fock densities has been introduced to investigate $\\alpha$-cluster structures in light nuclei. Compared to the local nucleonic densities, the nucleon localization function has been shown to be an excellent indicator of shell effects and cluster correlations. Using the spatial nucleon localization measure, we investigate the cluster structures in deformed light nuclei and study the emergence of fragments in fissioning heavy nuclei. To illustrate basic concepts of nucleon localization, we employ the deformed harmonic oscillator model. Realistic calculations are carried out using self-consistent nuclear density functional theory with quantified energy density functionals optimized for fission studies. We study particle densities and spatial nucleon localization distributions for deformed cluster configurations of $^{8}$Be and $^{20}$Ne, and also along...

  6. Reflections on cavitation nuclei in water

    DEFF Research Database (Denmark)

    Mørch, Knud Aage

    2007-01-01

    The origin of cavitation bubbles, cavitation nuclei, has been a subject of debate since the early years of cavitation research. This paper presents an analysis of a representative selection of experimental investigations of cavitation inception and the tensile strength of water. At atmospheric...... to explaining why the tensile strength of water varies so dramatically between the experiments reported. A model for calculation of the critical pressure of skin-covered free gas bubbles as well as that of interfacial gaseous nuclei covered by a skin is presented. This model is able to bridge the apparently...... pressure, the possibility of stabilization of free gas bubbles by a skin has been documented, but only within a range of bubble sizes that makes them responsible for tensile strengths up to about 1.5 bar, and values reaching almost 300 bar have been measured. However, cavitation nuclei can also be harbored...

  7. Alpha-cluster model of atomic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Sosin, Zbigniew; Kallunkathariyil, Jinesh [Jagiellonian University, M. Smoluchowski Institute of Physics, Krakow (Poland); Blocki, Jan [NCBJ, Theoretical Physics Division (BP2), Swierk (Poland); Lukasik, Jerzy; Pawlowski, Piotr [IFJ PAN, Krakow (Poland)

    2016-05-15

    The description of a nuclear system in its ground state and at low excitations based on the equation of state (EoS) around normal density is presented. In the expansion of the EoS around the saturation point, additional spin polarization terms are taken into account. These terms, together with the standard symmetry term, are responsible for the appearance of the α-like clusters in the ground-state configurations of the N=Z even-even nuclei. At the nuclear surface these clusters can be identified as alpha particles. A correction for the surface effects is introduced for atomic nuclei. Taking into account an additional interaction between clusters the binding energies and sizes of the considered nuclei are very accurately described. The limits of the EoS parameters are established from the properties of the α, {sup 3}He and t particles. (orig.)

  8. Shape phase mixing in critical point nuclei

    CERN Document Server

    Budaca, R

    2016-01-01

    Spectral properties of nuclei near the critical point of the quantum phase transition between spherical and axially symmetric shapes are studied in a hybrid collective model which combines the $\\gamma$-stable and $\\gamma$-rigid collective conditions through a rigidity parameter. The model in the lower and upper limits of the rigidity parameter recovers the X(5) and X(3) solutions respectively, while in the equally mixed case it corresponds to the X(4) critical point symmetry. Numerical applications of the model on nuclei from regions known for critical behavior reveal a sizable shape phase mixing and its evolution with neutron or proton numbers. The model also enables a better description of energy spectra and electromagnetic transitions for these nuclei.

  9. Statistical ensembles and fragmentation of finite nuclei

    Science.gov (United States)

    Das, P.; Mallik, S.; Chaudhuri, G.

    2017-09-01

    Statistical models based on different ensembles are very commonly used to describe the nuclear multifragmentation reaction in heavy ion collisions at intermediate energies. Canonical model results are more appropriate for finite nuclei calculations while those obtained from the grand canonical ones are more easily calculable. A transformation relation has been worked out for converting results of finite nuclei from grand canonical to canonical and vice versa. The formula shows that, irrespective of the particle number fluctuation in the grand canonical ensemble, exact canonical results can be recovered for observables varying linearly or quadratically with the number of particles. This result is of great significance since the baryon and charge conservation constraints can make the exact canonical calculations extremely difficult in general. This concept developed in this work can be extended in future for transformation to ensembles where analytical solutions do not exist. The applicability of certain equations (isoscaling, etc.) in the regime of finite nuclei can also be tested using this transformation relation.

  10. Monte Carlo approaches to light nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, J.

    1990-01-01

    Significant progress has been made recently in the application of Monte Carlo methods to the study of light nuclei. We review new Green's function Monte Carlo results for the alpha particle, Variational Monte Carlo studies of {sup 16}O, and methods for low-energy scattering and transitions. Through these calculations, a coherent picture of the structure and electromagnetic properties of light nuclei has arisen. In particular, we examine the effect of the three-nucleon interaction and the importance of exchange currents in a variety of experimentally measured properties, including form factors and capture cross sections. 29 refs., 7 figs.

  11. Statistical properties of quantum spectra in nuclei

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Some aspects of quantum chaos in a finite system have been studied based on the analysis of statistical behavior of quantum spectra in nuclei.The experiment data show the transition from order to chaos with increasing excitation energy in spherical nuclei.The dependence of the order to chaos transition on nuclear deformation and nuclear rotating is described.The influence of pairing effect on the order to chaos transition is also discussed.Some important experiment phenomena in nuclear physics have been understood from the point of view of the interplay between order and chaos.

  12. Computer Model Of Fragmentation Of Atomic Nuclei

    Science.gov (United States)

    Wilson, John W.; Townsend, Lawrence W.; Tripathi, Ram K.; Norbury, John W.; KHAN FERDOUS; Badavi, Francis F.

    1995-01-01

    High Charge and Energy Semiempirical Nuclear Fragmentation Model (HZEFRG1) computer program developed to be computationally efficient, user-friendly, physics-based program for generating data bases on fragmentation of atomic nuclei. Data bases generated used in calculations pertaining to such radiation-transport applications as shielding against radiation in outer space, radiation dosimetry in outer space, cancer therapy in laboratories with beams of heavy ions, and simulation studies for designing detectors for experiments in nuclear physics. Provides cross sections for production of individual elements and isotopes in breakups of high-energy heavy ions by combined nuclear and Coulomb fields of interacting nuclei. Written in ANSI FORTRAN 77.

  13. Medium energy hadron scattering from nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Ginocchio, J.N.; Wenes, G.

    1986-01-01

    The Glauber approximation for medium energy scattering of hadronic projectiles from nuclei is combined with the interacting boson model of nuclei to produce a transition matrix for elastic and inelastic scattering in algebraic form which includes coupling to all the intermediate states. We present closed form analytic expresions for the transition matrix elements for the three dynamical symmetries of the interacting boson model; that is for, a spherical quadrupole vibrator, a ..gamma.. unstable rotor, and both prolate and oblate axially symmetric rotors. We give examples of application of this formalism to proton scattering from /sup 154/Sm and /sup 154/Gd. 27 refs., 5 figs., 1 tab.

  14. Light nuclei from chiral EFT interactions

    Science.gov (United States)

    Navrátil, P.; Gueorguiev, V. G.; Vary, J. P.; Ormand, W. E.; Nogga, A.; Quaglioni, S.

    2008-12-01

    Recent developments in nuclear theory allow us to make a connection between quantum chromodynamics (QCD) and low-energy nuclear physics. First, chiral effective field theory (χEFT) provides a natural hierarchy to define two-nucleon ( NN), three-nucleon ( NNN), and even four-nucleon interactions. Second, ab-initio methods have been developed capable to test these interactions for light nuclei. In this contribution, we discuss ab-initio no-core shell-model (NCSM) calculations for s-shell and p-shell nuclei with NN and NNN interactions derived within χEFT.

  15. Mechanical Feedback from Active Galactic Nuclei in Galaxies, Groups, and Clusters

    CERN Document Server

    McNamara, B R

    2012-01-01

    The radiative cooling timescales at the centers of hot atmospheres surrounding elliptical galaxies, groups, and clusters are much shorter than their ages. Therefore, hot atmospheres are expected to cool and to form stars. Cold gas and star formation are observed in central cluster galaxies but at levels below those expected from an unimpeded cooling flow. X-ray observations have shown that wholesale cooling is being offset by mechanical heating from radio active galactic nuclei. Feedback is widely considered to be an important and perhaps unavoidable consequence of the evolution of galaxies and supermassive black holes. We show that cooling X-ray atmospheres and the ensuing star formation and nuclear activity are probably coupled to a self-regulated feedback loop. While the energetics are now reasonably well understood, other aspects of feedback are not. We highlight the problems of atmospheric heating and transport processes, accretion, and nuclear activity, and we discuss the potential role of black hole sp...

  16. Hot bitumen grouting rediscovered

    Energy Technology Data Exchange (ETDEWEB)

    Naudts, A. [ECO Grouting Specialists, Grand Valley, ON (Canada)

    2001-10-01

    The article extols the value of hot bitumen grouting, in conjunction with cement-based grout, as a fast, safe, environmentally-friendly and cost-effective sealant. A major advantage of bitumen grout is that blown bitumen will never wash out. The article discusses the properties and some applications of bitumen grout. A diagram shows an application of bitumen and cement-based grout at a large dam. Examples of preventing water flow in dams, in a coal mine and in a potash mine are also given.

  17. The statistical decay of very hot nuclei: from sequential decay to multifragmentation

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, B.V. [Centro Tecnico Aeroespacial (ITA/CTA), Sao Jose dos Campos, SP (Brazil). Inst. Tecnologico de Aeronautica; Donangelo, R. [Universidade Federal do Rio de Janeiro (IF/UFRJ), RJ (Brazil). Inst. de Fisica; Universidad de la Republica, Montevideo (Uruguay). Facultad de Ingenieria. Inst. de Fisica; Souza, S.R. [Universidade Federal do Rio de Janeiro (IF/UFRJ), RJ (Brazil). Inst. de Fisica; Universidade Federal do Rio Grande do Sul (IF/UFRGS), Porto Alegre, RS (Brazil). Inst. de Fisica; Lynch, W.G.; Steiner, A.W.; Tsang, M.B. [Michigan State University (NSCL/MSU), East Lansing, MI (United States). National Superconducting Cyclotron Lab.

    2010-07-01

    Full text. At low excitation energies, the compound nucleus typically decays through the sequential emission of light particles. As the energy increases, the emission probability of heavier fragments increases until, at sufficiently high energies, several heavy complex fragments are emitted during the decay. The extent to which this fragment emission is simultaneous or sequential has been a subject of theoretical and experimental study for almost 30 years. The Statistical Multifragmentation Model, an equilibrium model of simultaneous fragment emission, uses the configurations of a statistical ensemble to determine the distribution of primary fragments of a compound nucleus. The primary fragments are then assumed to decay by sequential compound emission or Fermi breakup. As the first step toward a more unified model of these processes, we demonstrate the equivalence of a generalized Fermi breakup model, in which densities of excited states are taken into account, to the microcanonical version of the statistical multifragmentation model. We then establish a link between this unified Fermi breakup / statistical multifragmentation model and the well-known process of compound nucleus emission, which permits to consider simultaneous and sequential emission on the same footing. Within this unified framework, we analyze the increasing importance of simultaneous, multifragment decay with increasing excitation energy and decreasing lifetime of the compound nucleus. (author)

  18. Charged particle decay of hot and rotating 88Mo nuclei in fusion-evaporation reactions

    Science.gov (United States)

    Valdré, S.; Piantelli, S.; Casini, G.; Barlini, S.; Carboni, S.; Ciemała, M.; Kmiecik, M.; Maj, A.; Mazurek, K.; Cinausero, M.; Gramegna, F.; Kravchuk, V. L.; Morelli, L.; Marchi, T.; Baiocco, G.; Bardelli, L.; Bednarczyk, P.; Benzoni, G.; Bini, M.; Blasi, N.; Bracco, A.; Brambilla, S.; Bruno, M.; Camera, F.; Chbihi, A.; Corsi, A.; Crespi, F. C. L.; D'Agostino, M.; Degerlier, M.; Fabris, D.; Fornal, B.; Giaz, A.; Krzysiek, M.; Leoni, S.; Matejska-Minda, M.; Mazumdar, I.; MÈ©czyński, W.; Million, B.; Montanari, D.; Myalski, S.; Nicolini, R.; Olmi, A.; Pasquali, G.; Prete, G.; Roberts, O. J.; Styczeń, J.; Szpak, B.; Wasilewska, B.; Wieland, O.; Wieleczko, J. P.; ZiÈ©bliński, M.

    2016-03-01

    A study of fusion-evaporation and (partly) fusion-fission channels for the 88Mo compound nucleus, produced at different excitation energies in the reaction 48Ti+40Ca at 300, 450, and 600 MeV beam energies, is presented. Fusion-evaporation and fusion-fission cross sections have been extracted and compared with the existing systematics. Experimental data concerning light charged particles have been compared with the prediction of the statistical model in its implementation in the gemini++ code, well suited even for high spin systems, in order to tune the main model parameters in a mass region not abundantly covered by exclusive experimental data. Multiplicities for light charged particles emitted in fusion evaporation events are also presented. Some discrepancies with respect to the prediction of the statistical model have been found for forward emitted α particles; they may be due both to pre-equilibrium emission and to reaction channels (such as deep inelastic collisions or quasifission/quasifusion) different from the compound nucleus formation.

  19. Charged particle decay of hot and rotating $^{88}$Mo nuclei in fusion-evaporation reactions

    CERN Document Server

    Valdré, S; Casini, G; Barlini, S; Carboni, S; Ciemała, M; Kmiecik, M; Maj, A; Mazurek, K; Cinausero, M; Gramegna, F; Kravchuk, V L; Morelli, L; Marchi, T; Baiocco, G; Bardelli, L; Bednarczyk, P; Benzoni, G; Bini, M; Blasi, N; Bracco, A; Brambilla, S; Bruno, M; Camera, F; Chbihi, A; Corsi, A; Crespi, F C L; D'Agostino, M; Degerlier, M; Fabris, D; Fornal, B; Giaz, A; Krzysiek, M; Leoni, S; Matejska-Minda, M; Mazumdar, I; Mȩczyński, W; Million, B; Montanari, D; Myalski, S; Nicolini, R; Olmi, A; Pasquali, G; Prete, G; Roberts, O J; Styczeń, J; Szpak, B; Wasilewska, B; Wieland, O; Wieleczko, J P; Ziȩbliński, M

    2015-01-01

    A study of fusion-evaporation and (partly) fusion-fission channels for the $^{88}$Mo compound nucleus, produced at different excitation energies in the reaction $^{48}$Ti + $^{40}$Ca at 300, 450 and 600 MeV beam energies, is presented. Fusion-evaporation and fusion-fission cross sections have been extracted and compared with the existing systematics. Experimental data concerning light charged particles have been compared with the prediction of the statistical model in its implementation in the Gemini++ code, well suited even for high spin systems, in order to tune the main model parameters in a mass region not abundantly covered by exclusive experimental data. Multiplicities for light charged particles emitted in fusion evaporation events are also presented. Some discrepancies with respect to the prediction of the statistical model have been found for forward emitted $\\alpha$-particles; they may be due both to pre-equilibrium emission and to reaction channels (such as Deep Inelastic Collisions, QuasiFission/Q...

  20. Superheavy dark matter

    CERN Document Server

    Riotto, Antonio

    2000-01-01

    It is usually thought that the present mass density of the Universe is dominated by a weakly interacting massive particle (WIMP), a fossil relic of the early Universe. Theoretical ideas and experimental efforts have focused mostly on production and detection of thermal relics, with mass typically in the range a few GeV to a hundred GeV. Here, we will review scenarios for production of nonthermal dark matter whose mass may be in the range 10/sup 12/ to 10/sup 19/ GeV, much larger than the mass of thermal wimpy WIMPS. We will also review recent related results in understanding the production of very heavy fermions through preheating after inflation. (19 refs).

  1. Observation of nuclei reassembled from demembranated Xenopus sperm nuclei and analysis of their lamina components

    Institute of Scientific and Technical Information of China (English)

    QUJIAN; CHUANMAOZHANG; 等

    1994-01-01

    A cell-free preparation obtained from extracts of activated Xenopus laevis eggs induced chromatin decondensation and nuclear formation from demembranated Xenopus sperm nuclei.Electron microscopy revealed that the reassembled nucleus had a double-layered nuclear memblane,nuclear pore complexes,and decondensed chromatin etc.Indirect immunofluorescence analysis demonstrated the presence of lamina in newly assembled nuclei.Western-blotting results showed that lamin LII was present in egg extracts and in lamina of the reassembled nuclei which were previously reported to contain only egg derived lamin LIII.

  2. Magnetic moments of odd spherical nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Levon, A.I.; Fedotkin, S.N.; Vdovin, A.I.

    1986-06-01

    Using the quasiparticle-phonon model, the magnetic moments of the ground state and several of the excited states are calculated for spherical nuclei. The polarization of the core is taken into account, by means of 1+ phonons, as well as 2/sup +/ and 3/sup -/ excitations, which give a collective contribution to the magnetic moment.

  3. Fisica degli atomi e dei nuclei

    CERN Document Server

    Bernardini, Carlo

    1965-01-01

    Evidenza della struttura atomica della materia ; le proprietà degli atomi e la meccanica atomica ; gli atomi e le radiazioni elettromagnetiche ; struttura microscopica dello stato gassoso ; struttura microscopica dello stato liquido ; struttura microscopica della stato solido ; proprietà elettriche e magnetiche delle sostanze ; proprietà dei nuclei degli atomi ; le particelle elementari.

  4. Precision lifetime measurements in light exotic nuclei

    Science.gov (United States)

    McCutchan, Elizabeth

    2017-01-01

    A new generation of ab-initio calculations, based on realistic two- and three-body forces have had a profound impact on our understanding of nuclei. They have shed light on topics such as the origin of effective forces (like spin-orbit and tensor interactions) and the mechanisms behind cluster and pairing correlations. New precise data are required to both better parameterize the three body forces and to improve numerical methods. A sensitive probe of the structure of light nuclei comes from their electromagnetic transition rates. A refined Doppler Shift Attenuation Method (DSAM) will be outlined which is used to precisely measure lifetimes in light nuclei and helps to reduce and quantity systematic uncertainties in the measurement. Using this careful DSAM, we have made a series of precise measurements of electromagnetic transition strengths in Li isotopes, A =10 nuclei, and the exotic halo nucleus, 12Be. Various phenomena, such as alpha clustering and meson-exchange currents, can be investigated in these seemingly simple systems, while the collection of data spanning stable to neutron-rich, allows us to probe the influence of additional valence neutrons. This talk will report on what has been learned, and the challenges that lie in the future, both in experiment and theory, as we push to describing and measuring even more exotic systems. Work supported by the Office of Nuclear Physics, Office of Science of the U.S. Department of Energy under contract No. DE-AC02-98CH10886.

  5. Test of Pseudospin Symmetry in Deformed Nuclei

    CERN Document Server

    Ginocchio, J N; Meng, J; Zhou, S G; Zhou, Shan-Gui

    2004-01-01

    Pseudospin symmetry is a relativistic symmetry of the Dirac Hamiltonian with scalar and vector mean fields equal and opposite in sign. This symmetry imposes constraints on the Dirac eigenfunctions. We examine extensively the Dirac eigenfunctions of realistic relativistic mean field calculations of deformed nuclei to determine if these eigenfunctions satisfy these pseudospin symmetry constraints.

  6. Magnetic Dipole Sum Rules for Odd Nuclei

    CERN Document Server

    Ginocchio, J N

    1997-01-01

    Sum rules for the total- and scissors-mode M1 strength in odd-A nuclei are derived within the single-j interacting boson-fermion model. We discuss the physical content and geometric interpretation of these sum rules and apply them to ^{167}Er and ^{161}Dy. We find consistency with the former measurements but not with the latter.

  7. Spectroscopic Studies of Exotic Nuclei at ISOLDE

    CERN Multimedia

    2002-01-01

    Experiment IS50 is designed to: a) Investigate the full range of the @b strength function of heavy (A~$>$~48)~K nuclei b)~Study the decay of isomeric states in n-deficient bromine nuclei (A~=~72 and 70). The heavy K isotopes appeared to have complex decay schemes, including feeding by the @b-decay of levels having open neutron channels (Beta decay energy Q(@b) exceeds neutron binding energy S^n); in addition, a large fraction of the delayed transitions populate excited levels in the daughter nuclei. The allowed @b-decay selects states in the daughter nucleus with wave functions having a large overlap with the initial state. Hence, the @b strength functions, deduced from these deca reveal simple structures correlated to the particle-hole excitation energies in the Ca nuclei. These results are valuable for the application of the shell-model calculations far from stability. The delayed neutron spectra are measured with a large area curved scintillator in coincidence either with high resolution Ge(Li) detectors, ...

  8. Physics of the continuum of borromean nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Vaagen, J.S.; Rogde, T. [Dept. of Physics, Univ. of Bergen (Norway); Danilin, B.V. [RRC The Kurchatov Inst., Kurchatov, Moscow (Russian Federation); Ershov, S.N. [JINR, Dubna, Moscow (Russian Federation); Thompson, I.J. [Dept. of Physics, Univ. of Surrey, Guildford (United Kingdom); Zhukov, M.V. [Chalmers Univ. of Technology and Goeteborg Univ., Goeteborg (Sweden); RNBT Collaboration

    1998-06-01

    The continuum states of two-neutron halo nuclei are calculated in the method of hyperspherical harmonics. Using DWIA theory appropriate for dilute halo matter we have probed the structure of the low-lying {sup 6}He continuum via calculations of charge-exchange and inelastic scattering. (orig.)

  9. On the Elastic Scattering of Heavy Nuclei

    Energy Technology Data Exchange (ETDEWEB)

    McIntosh, J. S.; Park, S. C.; Turner, J. E.

    1960-01-01

    A program is presented for determining the differential cross-section for the elastic scattering of heavy nuclei. It utilizes the unitary property of the S-matrix and a less drastic L-dependence of the absorption than the sharp cut-off model of Blair. it is shown that experimental data can be fitted quite well. (auth)

  10. Building Atomic Nuclei with the Dirac Equation

    OpenAIRE

    Serot, Brian D.

    2003-01-01

    The relevance of the Dirac equation for computations of nuclear structure is motivated and discussed. Quantitatively successful results for medium- and heavy-mass nuclei are described, and modern ideas of effective field theory and density functional theory are used to justify them.

  11. Heavy Mesons in Nuclear Matter and Nuclei

    CERN Document Server

    Tolos, Laura; Garcia-Recio, Carmen; Molina, Raquel; Nieves, Juan; Oset, Eulogio; Ramos, Angels; Romanets, Olena; Salcedo, Lorenzo Luis; Torres-Rincon, Juan M

    2014-01-01

    Heavy mesons in nuclear matter and nuclei are analyzed within different frameworks, paying a special attention to unitarized coupled-channel approaches. Possible experimental signatures of the properties of these mesons in matter are addressed, in particular in connection with the future FAIR facility at GSI.

  12. On the efficient acceleration of clouds in active galactic nuclei

    Science.gov (United States)

    Waters, Tim; Proga, Daniel

    2016-07-01

    In the broad line region of active galactic nuclei (AGN), acceleration occurs naturally when a cloud condenses out of the hot confining medium due to the increase in line opacity as the cloud cools. However, acceleration by radiation pressure is not very efficient when the flux is time-independent, unless the flow is 1D. Here, we explore how acceleration is affected by a time-varying flux, as AGN are known to be highly variable. If the period of flux oscillations is longer than the thermal time-scale, we expect the gas to cool during the low flux state, and therefore line opacity should quickly increase. The cloud will receive a small kick due to the increased radiation force. We perform hydrodynamical simulations using ATHENA to confirm this effect and quantify its importance. We find that despite the flow becoming turbulent in 2D due to hydrodynamic instabilities, a 20 per cent modulation of the flux leads to a net increase in acceleration - by more than a factor of 2 - in both 1D and 2D. We show that this acceleration is sufficient to produce the observed line widths, although we only consider optically thin clouds. We discuss the implications of our results for photoionization modelling and reverberation mapping.

  13. Jet evolution in hot and cold QCD matter

    Energy Technology Data Exchange (ETDEWEB)

    Domdey, Svend Oliver

    2010-07-23

    In this thesis, we study the evolution of energetic partons in hot and cold QCD matter. In both cases, interactions with the medium lead to energy loss of the parton and its transverse momentum broadens. The propagation of partons in cold nuclear matter can be investigated experimentally in deep-inelastic scattering (DIS) on nuclei. We use the dipole model to calculate transverse momentum broadening in DIS on nuclei and compare to experimental data from HERMES. In hot matter, the evolution of the parton shower is strongly modified. To calculate this modification, we construct an additional scattering term in the QCD evolution equations which accounts for scattering of partons in the quark-gluon plasma. With this scattering term, we compute the modified gluon distribution in the shower at small momentum fractions. Furthermore, we calculate the modified fragmentation function of gluons into pions. The scattering term causes energy loss of the parton shower which leads to a suppression of hadrons with large transverse momentum. In the third part of this thesis, we study double dijet production in hadron collisions. This process contains information about the transverse parton distribution of hadrons. As main result, we find that double dijet production will allow for a study of the transverse growth of hadronic wave functions at the LHC. (orig.)

  14. Experimental aspects of quarkonia production and suppression in cold and hot nuclear matter

    CERN Document Server

    Frawley, A D

    2015-01-01

    When heavy Quarkonia are formed in collisions between between nuclei, their production cross section is modified relative to that in p+p collisions. The physical effects that cause this modification fall into two categories. Hot matter effects are due to the large energy density generated in the nuclear collision, which disrupts the formation of the quarkonium state. Cold nuclear matter effects are due to the fact that the quarkonium state is created in a nuclear target. I will review experimental aspects of quarkonia production due to both hot and cold matter effects.

  15. Spectroscopic factors for two-proton radioactive nuclei

    Indian Academy of Sciences (India)

    Chinmay Basu

    2004-11-01

    Spectroscopic factors for two-proton emitting nuclei are discussed in the framework of the BCS (Bardeen–Cooper–Schriefer) model. Calculations carried out for the two-proton unstable 45Fe, 48Ni and 54Zn nuclei are presented.

  16. Whole-Cell Properties of Cerebellar Nuclei Neurons In Vivo

    NARCIS (Netherlands)

    Canto, Cathrin B; Witter, L.; De Zeeuw, C.I.

    2016-01-01

    Cerebellar nuclei neurons integrate sensorimotor information and form the final output of the cerebellum, projecting to premotor brainstem targets. This implies that, in contrast to specialized neurons and interneurons in cortical regions, neurons within the nuclei encode and integrate complex

  17. Incidence of centrally positioned nuclei in mouse masticatory muscle fibers

    DEFF Research Database (Denmark)

    Vilmann, A; Vilmann, H; Kirkeby, S

    1989-01-01

    Cross-sections of normal digastric, temporalis and masseter muscles from 7- and 30-week-old mice were studied for centrally positioned nuclei. Such nuclei were inhomogeneously distributed throughout each muscle and varied markedly between specimens. The incidence of centrally positioned nuclei......, the frequency in a given muscle was apparently age-independent. A connection between fiber type and centrally positioned nuclei is suggested....

  18. Flux of cosmic ray heavy nuclei enders behind low shielding

    CERN Document Server

    Allkofer, O C

    1975-01-01

    The authors investigate the number of stopping nuclei per cm/sup 3/ tissue hour as a function of absorbing material thickness. Fragmentation probabilities of heavy nuclei were deduced from the measured attenuation of the heavy nuclei flux in the atmosphere. Comparison is made with the results of the Biostack I experiment on board Apollo 16. (11 refs).

  19. Heavy Nuclei Synthesized in Gamma-Ray Burst Outflows as the Source of UHECRs

    CERN Document Server

    Metzger, Brian D; Horiuchi, Shunsaku

    2011-01-01

    Recent measurements by the Pierre Auger Observatory suggest that the composition of ultra-high energy cosmic rays (UHECRs) becomes dominated by heavy nuclei at high energies. However, until now there has been no astrophysical motivation for considering a source highly enriched in heavy elements. Here we demonstrate that the outflows from Gamma-Ray Bursts (GRBs) may indeed be composed primarily of nuclei with masses A ~ 40-200, which are synthesized as hot material expands away from the central engine. In particular, if the jet is magnetically-dominated (rather than a thermally-driven fireball) its low entropy enables heavy elements to form efficiently. Adopting the millisecond proto-magnetar model for the GRB central engine, we show that heavy nuclei are both synthesized in proto-magnetar winds and can in principle be accelerated to energies >1e20 eV in the shocks or regions of magnetic reconnection that are responsible for powering the GRB. Similar results may apply to accretion-powered GRB models if the jet...

  20. The Revealing Dust: Mid-Infrared Activity in Hickson Compact Group Galaxy Nuclei

    CERN Document Server

    Gallagher, S C; Hornschemeier, A E; Charlton, J C; Hibbard, J E

    2007-01-01

    We present a sample of 46 galaxy nuclei from 12 nearby (z<4500 km/s) Hickson Compact Groups (HCGs) with a complete suite of 1-24 micron 2MASS+Spitzer nuclear photometry. For all objects in the sample, blue emission from stellar photospheres dominates in the near-IR through the 3.6 micron IRAC band. Twenty-five of 46 (54%) galaxy nuclei show red, mid-IR continua characteristic of hot dust powered by ongoing star formation and/or accretion onto a central black hole. We introduce alpha_{IRAC}, the spectral index of a power-law fit to the 4.5-8.0 micron IRAC data, and demonstrate that it cleanly separates the mid-IR active and non-active HCG nuclei. This parameter is more powerful for identifying low to moderate-luminosity mid-IR activity than other measures which include data at rest-frame lambda<3.6 micron that may be dominated by stellar photospheric emission. While the HCG galaxies clearly have a bimodal distribution in this parameter space, a comparison sample from the Spitzer Nearby Galaxy Survey (SIN...

  1. On the Hot Money Trail

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The huge influx of international hot money is threatening inflation and affecting the country’s monetary policy In the last three months, the country’s financial supervisory departments have conducted frequent but atypical investi-gations of hot money.

  2. How hot is the sun

    Institute of Scientific and Technical Information of China (English)

    刘超

    2001-01-01

    Do you know how hot thesun is? There are no solidsor liquids on the sun. Why not? The temperature onoutside the sun is more than 10, 000℃, and that at the centre is about 20, 000, 000℃.The sun is so hot that all thesolids and all the liquids havebeen turned into gases.

  3. Nuclear structure features of very heavy and superheavy nuclei—tracing quantum mechanics towards the ‘island of stability’

    Science.gov (United States)

    Ackermann, D.; Theisen, Ch

    2017-08-01

    The quantum-mechanic nature of nuclear matter is at the origin of the vision of a region of enhanced stability at the upper right end of the chart of nuclei, the so-called ‘island of stability’. Since the 1960s in the early second half of the last century, various models predict closed shells for proton numbers 114-126 and neutron numbers such as 172 or 184. Being stabilized by quantum-mechanic effects only, those extremely heavy man-made nuclear species are an ideal laboratory to study the origin of the strong nuclear interaction which is the driving force for matter properties in many fields ranging from microscopic scales like hadronic systems to cosmic scales in stellar environments like neutron stars. Since the 1950s, experiments on the synthesis of new elements and isotopes have also revealed various exciting nuclear structure features. The contribution of Bohr, Mottelson and Rainwater with, in particular, the development of the unified model played an essential role in this context. Although not anticipated in the region of the heaviest nuclei, many phenomena were subsequently discovered like the interplay of collective features manifesting themselves e.g. in nuclear deformation, ranging from spherical to prolate and oblate shapes with the possible occurrence of triaxial symmetries, and single particle states and their excitation into quasiparticle configurations. The continuous development of modern experimental techniques employing advanced detection set-ups was essential to reveal these exciting nuclear structure aspects in the actinide and transactinide regions since the production cross-section becomes extremely small with increasing mass and charge. Further technological progress, in particular, high intensity stable ion beam accelerator facilities presently under construction, as well as potentially in the farther future radioactive neutron rich ion beams provide a high discovery potential for the basic understanding of nuclear matter.

  4. Predictions of synthesizing element 119 and 120

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The evaporation residue cross sections of synthesizing superheavy nuclei Z=119, 120 are calculated by different sets of master equations with different dynamical variables. Two methods basically predicted similar results that the Ca induced hot fusion can 48 produce element 119 easier than produce 120, and the evaporation residue cross sections for 119 are detectable by current advanced techniques, while the evaporation residue cross sections are below 0.1 pb for producing element 120.

  5. DAPI fluorescence in nuclei isolated from tumors.

    Science.gov (United States)

    Krishan, Awtar; Dandekar, Payal D

    2005-08-01

    In DNA histograms of some human solid tumors stained with nuclear isolation medium--4,6-diamidino-2-phenylindole dihydrochloride (NIM-DAPI), the coefficient of variation (CV) of the G0/G1 peak was broad, and in nuclear volume vs DNA scattergrams, a prominent slope was seen. To determine the cause for this, nuclei from frozen breast tumors were stained with NIM-DAPI and analyzed after dilution or resuspension in PBS. In two-color (blue vs red) analysis, most of the slope and broad CV was due to red fluorescence of nuclei stained with NIM-DAPI, which was reduced on dilution or resuspension in PBS, resulting in elimination of the slope and tightening of the CV.

  6. Clustering in stable and exotic nuclei

    CERN Document Server

    Beck, C

    2016-01-01

    Since the pioneering discovery of molecular resonances in the 12C+12C reaction more than half a century ago a great deal of research work has been undertaken in alpha clustering. Our knowledge on physics of nuclear molecules has increased considerably and nuclear clustering remains one of the most fruitful domains of nuclear physics, facing some of the greatest challenges and opportunities in the years ahead. The occurrence of "exotic" shapes and Bose-Einstein alpha condensates in light N=Z alpha-conjugate nuclei is investigated. Various approaches of the superdeformed and hyperdeformed bands associated with quasimolecular resonant structures are presented. Evolution of clustering from stability to the drip-lines is examined: clustering aspects are, in particular, discussed for light exotic nuclei with large neutron excess such as neutron-rich Oxygen isotopes with their complete spectroscopy.

  7. Shell model for warm rotating nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Matsuo, M.; Yoshida, K. [Kyoto Univ. (Japan); Dossing, T. [Univ. of Copenhagen (Denmark)] [and others

    1996-12-31

    Utilizing a shell model which combines the cranked Nilsson mean-field and the residual surface and volume delta two-body forces, the authors discuss the onset of rotational damping in normal- and super-deformed nuclei. Calculation for a typical normal deformed nucleus {sup 168}Yb indicates that the rotational damping sets in at around 0.8 MeV above the yrast line, and about 30 rotational bands of various length exists at a given rotational frequency, in overall agreement with experimental findings. It is predicted that the onset of rotational damping changes significantly in different superdeformed nuclei due to the variety of the shell gaps and single-particle orbits associated with the superdeformed mean-field.

  8. Collective properties of drip-line nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Hamamoto, I. [Univ. of Lund (Sweden); Sagawa, H. [Univ. of Aizu, Fukushima (Japan)

    1996-12-31

    Performing the spherical Hartree-Fock (HF) calculations with Skyrme interactions and, then, using RPA solved in the coordinate space with the Green`s function method, the authors have studied the effect of the unique shell structure as well as the very low particle threshold on collective modes in drip line nuclei. In this method a proper strength function in the continuum is obtained, though the spreading width of collective modes is not included. They have examined also one-particle resonant states in the obtained HF potential. Unperturbed particle-hole (p-h) response functions are carefully studied, which contain all basic information on the exotic behaviour of the RPA strength function in drip line nuclei.

  9. Simulation of nuclei morphologies for binary alloy

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    We study the critical nuclei morphologies of a binary alloy by the string method. The dynamic equation of the string, connecting the metastable phase (liquid) and stable phase (solid), is governed by Helmholtz free energy for the binary alloy system at a given temperature. The stationary string through the critical nucleus (saddle point) is obtained if the relaxation time of the string is su?ciently large. The critical nucleus radius and energy barrier to nucleation of a pure alloy with isotropic interface energy in two and three dimensions are calculated, which are consistent with the classical nucleation theory. The critical nuclei morphologies are sensitive to the anisotropy strength of interface energy and interface thickness of alloy in two and three dimensions. The critical nucleus and energy barrier to nucleation become smaller if the anisotropy strength of the interface energy is increased, which means that it is much easier to form a stable nucleus if the anisotropy of the interface energy is considered.

  10. Gamma spectroscopy of neutron rich actinide nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Birkenbach, Benedikt; Geibel, Kerstin; Vogt, Andreas; Hess, Herbert; Reiter, Peter; Steinbach, Tim; Schneiders, David [Koeln Univ. (Germany). IKP; Collaboration: AGATA-Collaboration

    2013-07-01

    Excited states in neutron-rich actinide Th and U nuclei were investigated after multi nucleon transfer reactions employing the AGATA demonstrator and PRISMA setup at LNL (INFN, Italy). A primary {sup 136}Xe beam of 1 GeV hitting a {sup 238}U target was used to produce the nuclei of interest. Beam-like reaction products of Xe- and Ba isotopes after neutron transfer were selected by the PRISMA spectrometer. The recoil like particles were registered by a MCP detector inside the scattering chamber. Coincident γ-rays from excited states in beam and target like particles were measured with the position sensitive AGATA HPGe detectors. Improved Doppler correction and quality of the γ-spectra is based on the novel γ-ray tracking technique which was successfully exploited. First results on the collective properties of various Th and U isotopes are discussed.

  11. Isospin Mixing In N $\\approx$ Z Nuclei

    CERN Multimedia

    Srnka, D; Versyck, S; Zakoucky, D

    2002-01-01

    Isospin mixing in N $\\approx$ Z nuclei region of the nuclear chart is an important phenomenon in nuclear physics which has recently gained theoretical and experimental interest. It also forms an important nuclear physics correction in the precise determination of the $ft$-values of superallowed 0$^+ \\rightarrow 0^+ \\beta$- transitions. The latter are used in precision tests of the weak interaction from nuclear $\\beta$- decay. We propose to experimentally measure isospin mixing into nuclear ground states in the N $\\approx$ Z region by determining the isospin forbidden Fermi-component in the Gamow-Teller dominated $J^{\\pi} \\rightarrow J^{\\pi} \\beta$- transitions through the observation of anisotropic positron emission from oriented nuclei. First measurements were carried out with $^{71}$As and are being analyzed now.

  12. Antiproton Induced Fission and Fragmentation of Nuclei

    CERN Multimedia

    2002-01-01

    The annihilation of slow antiprotons with nuclei results in a large highly localized energy deposition primarily on the nuclear surface. \\\\ \\\\ The study of antiproton induced fission and fragmentation processes is expected to yield new information on special nuclear matter states, unexplored fission modes, multifragmentation of nuclei, and intranuclear cascades.\\\\ \\\\ In order to investigate the antiproton-nucleus interaction and the processes following the antiproton annihilation at the nucleus, we propose the following experiments: \\item A)~Measurement of several fragments from fission and from multifragmentation in coincidence with particle spectra, especially neutrons and kaons. \\item B)~Precise spectra of $\\pi$, K, n, p, d and t with time-of-flight techniques. \\item C)~Installation of the Berlin 4$\\pi$ neutron detector with a 4$\\pi$ Si detector placed inside for fragments and charged particles. This yields neutron multiplicity distributions and consequently distributions of thermal excitation energies and...

  13. Electromagnetic interactions with nuclei and nucleons

    Energy Technology Data Exchange (ETDEWEB)

    Thornton, S.T.; Sealock, R.M.

    1990-11-10

    This report discusses the following topics: general LEGS work; photodisintegration of the deuteron; progress towards other experiments; LEGS instrumentation; major LEGS software projects; NaI detector system; nucleon detector system; waveshifting fibers; EGN prototype detector for CEBAF; photon beam facility at CEBAF; delta electroproduction in nuclei; quasielastic scattering and excitation of the Delta by {sup 4}He(e,e{prime}); and quasielastic scattering at high Q{sup 2}.

  14. Spin-isospin resonances in nuclei

    NARCIS (Netherlands)

    Fujiwara, M; Akimune, H; Daito, [No Value; Ejiri, H; Fujita, Y; Greenfield, MB; Harakeh, MN; Inomata, T; Janecke, J; Nakayama, S; Takemura, N; Tamii, A; Tanaka, M; Toyokawa, H; Yosoi, M

    1996-01-01

    Spin-isospin excitations in nuclei have been investigated via the (He-3,t) reaction at 450 MeV. The volume integrals of the effective interactions J(sigma tau) and J(tau) for the (He-3,t) reaction at 450 MeV have been empirically determined to be 172+/-17 MeV-fm(3) and 53+/-5 MeV-fm(3), respectively

  15. Understanding active galactic nuclei: peeling the onion.

    Science.gov (United States)

    Krolik, J. H.

    A brief review is presented of selected current problems in understanding active galactic nuclei, with special emphasis on the contributions that X-ray observations can make. Questions having to do with: how the character of the host galaxy influences nuclear activity; emission line regions; the border between the nucleus and the stellar portion of the active galaxy; radiation of the nonthermal continuum; and the possible existence of an accretion disk are touched upon.

  16. Light nuclei production in heavy ion collisions

    CERN Document Server

    Khan, K H; Wazir, Z; Khan, E U; Haseeb, Mahnaz Q; Ajaz, M

    2009-01-01

    Light nuclei production as a result of nuclear coalescence effect can give some signals on final state of Quark Gluon Plasma formation. We are studying the behavior of nuclear modification factor as a function of different variables using the simulated data coming from the FASTMC generator. This data is necessary to extract information on coalescence mechanism from experimental data on high energy nuclear-nuclear interactions.

  17. SEARCH FOR NUCLEI CONTAINING TWO STRANGE QUARKS.

    Energy Technology Data Exchange (ETDEWEB)

    MAY,M.

    1997-10-13

    This paper discusses a search for nuclei containing two strange quarks performed at Brookhaven National Laboratory. The goals and approach of experiment E885 are reviewed. Preliminary missing mass spectra for a subset of the data are presented, showing sensitivity for {Xi} hypernuclei and H particle searches. Existence of an angular correlation between pions in the sequential decay of {Lambda}{Lambda} hypernuclei is suggested on theoretical grounds.

  18. Search for nuclei containing two strange quarks

    Energy Technology Data Exchange (ETDEWEB)

    May, M.

    1997-12-31

    This paper discusses a search for nuclei containing two strange quarks performed at Brookhaven National Laboratory. The goals and approach of experiment E885 are reviewed. Preliminary missing mass spectra for a subset of the data are presented, showing sensitivity for {Xi} hypernuclei and H particle searches. Existence of an angular correlation between pions in the sequential decay of {Lambda}{Lambda} hypernuclei is suggested on theoretical grounds.

  19. Green's function calculations of light nuclei

    Science.gov (United States)

    Sun, ZhongHao; Wu, Qiang; Xu, FuRong

    2016-09-01

    The influence of short-range correlations in nuclei was investigated with realistic nuclear force. The nucleon-nucleon interaction was renormalized with V lowk technique and applied to the Green's function calculations. The Dyson equation was reformulated with algebraic diagrammatic constructions. We also analyzed the binding energy of 4He, calculated with chiral potential and CD-Bonn potential. The properties of Green's function with realistic nuclear forces are also discussed.

  20. AMS with light nuclei at small accelerators

    Science.gov (United States)

    Stan-Sion, C.; Enachescu, M.

    2017-06-01

    AMS applications with lighter nuclei are presented. It will be shown how Carbon-14, Boron-10, Beryllium-10, and Tritium-3 can be used to provide valuable information in forensic science, environmental physics, nuclear pollution, in material science and for diagnose of the plasma confinement in fusion reactors. Small accelerators are reliable, efficient and possess the highest ion beam transmissions that confer high precision in measurements.