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Sample records for medium heavy nuclei

  1. Medium-heavy nuclei from nucleon-nucleon interactions in lattice QCD

    NASA Astrophysics Data System (ADS)

    Inoue, Takashi; Aoki, Sinya; Charron, Bruno; Doi, Takumi; Hatsuda, Tetsuo; Ikeda, Yoichi; Ishii, Noriyoshi; Murano, Keiko; Nemura, Hidekatsu; Sasaki, Kenji; HAL QCD Collaboration

    2015-01-01

    On the basis of the Brueckner-Hartree-Fock method with the nucleon-nucleon forces obtained from lattice QCD simulations, the properties of the medium-heavy doubly magic nuclei such as 16O and 40Ca are investigated. We found that those nuclei are bound for the pseudoscalar meson mass MPS≃470 MeV. The mass number dependence of the binding energies, single-particle spectra, and density distributions are qualitatively consistent with those expected from empirical data at the physical point, although these hypothetical nuclei at heavy quark mass have smaller binding energies than the real nuclei.

  2. Structure properties of medium and heavy exotic nuclei

    NASA Astrophysics Data System (ADS)

    Gaidarov, M. K.

    2012-09-01

    Investigations of important characteristics of the structure of nuclei near drip-lines in coordinate and momentum space have been performed. The charge form factors, charge and matter densities and the corresponding rms radii for even-even isotopes of Ni, Kr, and Sn are calculated in the framework of deformed self-consistent mean field Skyrme DDHF+BCS method. The resulting charge radii and neutron skin thicknesses of these nuclei are compared with available experimental data, as well as with other theoretical predictions. The formation of a neutron skin is analyzed in terms of various definitions. Its correlation with the nuclear symmetry energy is studied within the coherent density fluctuation model using the symmetry energy as a function of density within the Brueckner energy-density functional. The nucleon momentum distributions for the same isotopic chains of neutron-rich nuclei are studied in the framework of the same mean-field method, as well as of theoretical correlation methods based on light-front dynamics and local density approximation. The isotopic sensitivities of the calculated neutron and proton momentum distributions are investigated together with the effects of nucleon correlations and deformation of nuclei.

  3. Properties of high-energy isoscalar monopole excitations in medium-heavy mass spherical nuclei

    SciTech Connect

    Gorelik, M. L. Shlomo, Sh. Tulupov, B. A. Urin, M. H.

    2015-07-15

    The recently developed particle-hole dispersive optical model is applied to describe properties of high-energy isoscalar monopole excitations in medium-heavy mass spherical nuclei. In particular, the double transition density averaged over the energy of the isoscalar monopole excitations is considered for {sup 208}Pb in a wide energy interval, which includes the isoscalar giant monopole resonance and its overtone. The energy-averaged strength functions of these resonances are also analyzed.

  4. Extracting nuclear sizes of medium to heavy nuclei from total reaction cross sections

    NASA Astrophysics Data System (ADS)

    Horiuchi, W.; Hatakeyama, S.; Ebata, S.; Suzuki, Y.

    2016-04-01

    Background: Proton and neutron radii are fundamental quantities of atomic nuclei. To study the sizes of short-lived unstable nuclei, there is a need for an alternative to electron scattering. Purpose: The recent paper by Horiuchi et al. [Phys. Rev. C 89, 011601(R) (2014)], 10.1103/PhysRevC.89.011601 proposed a possible way of extracting the matter and neutron-skin thickness of light- to medium-mass nuclei using total reaction cross section, σR. The analysis is extended to medium to heavy nuclei up to lead isotopes with due attention to Coulomb breakup contributions as well as density distributions improved by paring correlation. Methods: We formulate a quantitative calculation of σR based on the Glauber model including the Coulomb breakup. To substantiate the treatment of the Coulomb breakup, we also evaluate the Coulomb breakup cross section due to the electric dipole field in a canonical-basis-time-dependent-Hartree-Fock-Bogoliubov theory in the three-dimensional coordinate space. Results: We analyze σR's of 103 nuclei with Z =20 , 28, 40, 50, 70, and 82 incident on light targets, H,21, 4He, and 12C. Three kinds of Skyrme interactions are tested to generate those wave functions. To discuss possible uncertainty due to the Coulomb breakup, we examine its dependence on the target, the incident energy, and the Skyrme interaction. The proton is a most promising target for extracting the nuclear sizes as the Coulomb excitation can safely be neglected. We find that the so-called reaction radius, aR=√{σR/π } , for the proton target is very well approximated by a linear function of two variables, the matter radius and the skin thickness, in which three constants depend only on the incident energy. We quantify the accuracy of σR measurements needed to extract the nuclear sizes. Conclusions: The proton is the best target because, once the incident energy is set, its aR is very accurately determined by only the matter radius and neutron-skin thickness. If σR's at

  5. On the excitation energy of deep-hole states in medium-heavy-mass spherical nuclei

    NASA Astrophysics Data System (ADS)

    Kolomiytsev, G. V.; Igashov, S. Yu.; Urin, M. H.

    2016-01-01

    Within the particle-hole dispersive optical model it is shown that the spreading effect determines a significant part of the anomalously large excitation energy of deep-hole states in the 90Zr and 208Pb parent nuclei.

  6. Super-heavy nuclei

    NASA Astrophysics Data System (ADS)

    Hofmann, Sigurd

    2015-11-01

    Scientifically based searches for elements beyond uranium started after the discovery of the neutron. Neutrons captured by uranium nuclei and subsequent {β }- decay, similarly as most of the elements were produced in nature, was the successful method applied. However, as a first result, Hahn and Strassmann discovered nuclear fission indicating a limit for the existence of nuclei at an increasing number of protons. Eventually, the nuclear shell model allowed for a more accurate calculation of binding energies, half-lives and decay modes of the heaviest nuclei. Theoreticians predicted a region of increased stability at proton number Z = 126, later shifted to 114, and neutron number N = 184. These nuclei receive their stability from closed shells for the protons and neutrons. Later, increased stability was also predicted for deformed nuclei at Z = 108 and N = 162. In this review I will report on experimental work performed on research to produce and identify these super-heavy nuclei (SHN). Intensive heavy ion beams, sophisticated target technology, efficient electromagnetic ion separators, and sensitive detector arrays were the prerequisites for discovery of 12 new elements during the last 40 years. The results are described and compared with theoretical predictions and interpretations. An outlook is given on further improvement of experimental facilities which will be needed for exploration of the extension and structure of the island of SHN, in particular for searching for isotopes with longer half-lives predicted to be located in the south east of the island, for new elements, and last not least, for surprises which, naturally, emerge unexpectedly.

  7. Proton Distribution in Heavy Nuclei

    DOE R&D Accomplishments Database

    Johnson, M. H; Teller, E.

    1953-11-13

    It is reasoned that, from considerations connected with beta-decay stability and Coulomb repulsion forces, a neutron excess is developed on the surface of heavy nuclei. Several consequences of this qualitative analysis in nucleon interactions are briefly noted. (K.S.)

  8. Formation of Slow Heavy Mesons in Nuclei

    NASA Astrophysics Data System (ADS)

    Hirenzaki, Satoru

    2009-10-01

    Meson - nucleus systems such as mesic atoms and mesic nuclei have been studied systematically for a long time. The binding energies and widths of these bound states provide us unique and valuable information on the meson-nucleus interactions. In addition, the measurements of light vector meson spectra in nucleus as the invariant mass of lepton pairs have also provided interesting information. So far, the properties of relatively light mesons have been studied well both theoretically and experimentally. In this contribution, to extend our studies to a domain of heavier mesons, we would like to report recent research activities on the formation of heavy mesons in nuclei with small momenta. We think it is very interesting to consider the in-medium properties of heavier mesons including heavy quark contents. As a first step to heavier mesons, we will report our studies on formation of slow phi meson in nuclei. In-medium properties of phi meson have been studied theoretically, which have close relation to K and K-bar meson properties in medium because of the strong coupling of phi to K and K-bar. The study of QCD sum rule and the data taken at KEK suggested 3 percent mass reduction of phi at the normal nuclear density, while the phi meson selfenergy calculated in some effective models indicated a significantly smaller attractive potential for phi. We will show the calculated spectra for some reactions.

  9. Deformed shell model calculations of half lives for β+/EC decay and 2ν β+β+/β+EC/ECEC decay in medium-heavy N~Z nuclei

    NASA Astrophysics Data System (ADS)

    Mishra, S.; Shukla, A.; Sahu, R.; Kota, V. K. B.

    2008-08-01

    The β+/EC half-lives of medium heavy N~Z nuclei with mass number A~64-80 are calculated within the deformed shell model (DSM) based on Hartree-Fock states by employing a modified Kuo interaction in (2p3/2,1f5/2,2p1/2,1g9/2) space. The DSM model has been quite successful in predicting many spectroscopic properties of N~Z medium heavy nuclei with A~64-80. The calculated β+/EC half-lives, for prolate and oblate shapes, compare well with the predictions of the calculations with Skyrme force by Sarriguren Going further, following recent searches, half-lives for 2ν β+β+/β+EC/ECEC decay for the nucleus Kr78 are calculated using DSM and the results compare well with QRPA predictions.

  10. Fusion probability in heavy nuclei

    NASA Astrophysics Data System (ADS)

    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, , 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. 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: 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 . Approximate boundaries have been obtained from where 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 from unity marks the beginning of the domain of dynamical models of fusion. Availability of precise ER cross

  11. Clusterization and Deformation in Heavy Nuclei

    SciTech Connect

    Algora, A.; Cseh, J.; Darai, J.; Hess, P.O.; Antonenko, N.V.; Jolos, R.V.; Scheid, W.

    2005-11-21

    The deformation-dependence of clusterization in heavy nuclei is investigated. In particular, allowed and forbidden cluster-configurations are determined for the ground, superdeformed, and hyperdeformed states of some nuclei, based on a microscopic (effective SU(3)) selection rule. The stability of the different cluster configurations from the viewpoint of the binding energy and the dinuclear system model (DNS) is also investigated.

  12. Review of metastable states in heavy nuclei.

    PubMed

    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 [Formula: see text]. 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. PMID:27243336

  13. Review of metastable states in heavy nuclei

    NASA Astrophysics Data System (ADS)

    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.

  14. Octupole shapes in heavy nuclei

    SciTech Connect

    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.

  15. The acceleration of heavy nuclei in solar flares

    NASA Technical Reports Server (NTRS)

    Sakurai, K.

    1974-01-01

    The overabundance of heavy nuclei in solar cosmic rays of energy approximately 5 Mev/nucleon is explained by taking into account the pre-flare ionization states of these nuclei in the region where they are accelerated. A model is proposed which considers two-step accelerations associated with the initial development of solar flares. The first step is closely related to the triggering process of flares, while the second one starts with the development of the explosive phase. Further ionization of medium and heavy nuclei occurs through their interaction with Kev electrons accelerated by the first-step acceleration. It is suggested that the role of these electrons is important in producing fully ionized atoms in the acceleration regions.

  16. The acceleration of heavy nuclei in solar flares

    NASA Technical Reports Server (NTRS)

    Sakurai, K.

    1975-01-01

    The overabundance of heavy nuclei in solar cosmic rays of energy below about 10 MeV/nucleon is explained by taking into account the pre-flare ionization states of these nuclei in the region where they are accelerated. A model is proposed which considers two-step accelerations associated with the initial development of solar flares. The first step is closely related to the triggering process of flares, while the second one starts with the development of the explosive phase. Further ionization of medium and heavy nuclei occurs through their interaction with keV electrons accelerated by the first-step acceleration. It is suggested that the role of these electrons is important in producing fully ionized atoms in the acceleration regions.

  17. The Heavy Nuclei Explorer (HNX) Mission

    NASA Technical Reports Server (NTRS)

    Binns, W. R.

    2001-01-01

    The Heavy Nuclei eXplorer (HNX) mission was recently selected by NASA for a Small Explorer (SMEX) Mission Concept Study to begin in 2001. The primary scientific objectives of HNX are to measure the age of the galactic cosmic rays (GCR) since nucleosynthesis, determine the injection mechanism for the GCR accelerator (Volatility or FIP), and study the mix of nucleosynthetic processes that contribute to the source of GCRs. The experimental goal of HNX is to measure the elemental abundances of all individual stable nuclei from neon through the actinides and possibly beyond. HNX is composed of two instruments: ECCO, which measures elemental abundances of nuclei with Z(sup 3)72, and ENTICE, which measures elemental abundances of nuclei with 10(f)Z(f)82. We will discuss the mission and the science that can be addressed by HNX.

  18. Exotic nuclei with open heavy flavor mesons

    SciTech Connect

    Yasui, Shigehiro; Sudoh, Kazutaka

    2009-08-01

    We propose stable exotic nuclei bound with D and B mesons with respect to heavy quark symmetry. We indicate that an approximate degeneracy of D(B) and D*(B*) mesons plays an important role, and discuss the stability of DN and BN bound states. We find the binding energies 1.4 MeV and 9.4 MeV for each state in the J{sup P}=1/2{sup -} with the I=0 channel. We discuss also possible existence of exotic nuclei DNN and BNN.

  19. Nuclei at HERA and heavy ion physics

    SciTech Connect

    Gavin, S.; Strikman, M.

    1995-12-31

    Copies of 16 viewgraph sets from a workshop held at Brookhaven National Laboratory, 17-18 November, 1995. Titles of talks: HERA: The Present; HERA: Potential with Nuclei; Review of Hadron-Lepton Nucleus Data; Fermilab E665: results in muon scattering; Interactions of Quarks and Gluons with Nuclear Matter; Rescattering in Nuclear Targets for Photoproduction and DIS; Structure Functions and Nuclear Effect at PHENIX; Probing Spin-Averaged and Spin-Dependent Parton Distributions Using the Solenoidal Tracker at RHIC (STAR); Jet Quenching in eA, pA, AA; Nuclear Gluon Shadowing via Continuum Lepton Pairs; What can we learn from HERA with a colliding heavy ion beam? The limiting curve of leading particles at infinite A; Coherent Production of Vector Mesons off Light Nuclei in DIS; A Model of High Parton Densities in PQCD; Gluon Production for Weizaecker-Williams Field in Nucleus-Nucleus Collisions; Summary Talk.

  20. Propagation of heavy cosmic-ray nuclei

    NASA Technical Reports Server (NTRS)

    Letaw, J. R.; Silberberg, R.; Tsao, C. H.

    1984-01-01

    Techniques for modeling the propagation of heavy cosmic-ray nuclei, and the required atomic and nuclear data, are assembled in this paper. Emphasis is on understanding nuclear composition in the charge range Z = 3-83. Details of the application of 'matrix methods' above a few hundred MeV/nucleon, a new treatment of electron capture decay, and a new table of cosmic ray-stable isotopes are presented. Computation of nuclear fragmentation cross sections, stopping power, and electron stripping and attachment are briefly reviewed.

  1. Heavy-particle radioactivity of superheavy nuclei.

    PubMed

    Poenaru, D N; Gherghescu, R A; Greiner, W

    2011-08-01

    The concept of heavy-particle radioactivity (HPR) is changed to allow emitted particles with Z(e) > 28 from parents with Z > 110 and daughter around (208)Pb. Calculations for superheavy (SH) nuclei with Z = 104-124 are showing a trend toward shorter half-lives and larger branching ratio relative to α decay for heavier SHs. It is possible to find regions in which HPR is stronger than alpha decay. The new mass table AME11 and the theoretical KTUY05 and FRDM95 masses are used to determine the released energy. For 124 we found isotopes with half-lives in the range of ns to ps. PMID:21902317

  2. Ultra heavy nuclei in the cosmic radiation

    NASA Technical Reports Server (NTRS)

    Binns, W. Robert

    1988-01-01

    This paper describes the measurements of the ultraheavy cosmic ray abundances obtained by the Heavy Nuclei Experiment aboard the NASA High Energy Astronomy Observatory-3. It is found that the cosmic ray abundances are in broad agreement with solar system abundances with a step-FIP fractionation model applied although in detail there are some differences. In particular, Ge and Pb appear to be underabundant in the cosmic radiation. Although the platinum/lead ratio and the actinides are consistent with some r-process enhancement, the cosmic ray source is not dominated by the r-process up through the 50s as evidenced by the Sr/Rb ratio and by the abundance of Sn and Ba. The actinides are not greatly enhanced, ruling out freshly synthesized r-process production as the primary source of the heavy cosmic rays.

  3. Interactions of heavy nuclei, Kr, Xe and Ho, in light targets

    NASA Technical Reports Server (NTRS)

    Kertzman, M. P.; Klarmann, J.; Newport, B. J.; Stone, E. C.; Waddington, C. J.; Binns, W. R.; Garrard, T. L.; Israel, M. H.

    1985-01-01

    Over the past few years, the HEAO-3 measurements of the abundance of ultra-heavy cosmic ray nuclei (Z 26) at Earth were analyzed. In order to interpret these abundances in terms of a source composition, allowances must be made for the propagation of the nuclei in the interstellar medium. Vital to any calculation of the propagation is a knowlege of the total and partial interaction cross sections for these heavy nuclei on hydrogen. Until recently, data on such reactions have been scarce. The semi-empirical formalism of Silberberg and Tsao were relied upon to predict the partial cross sections. However, now that relativistic heavy ion beams are available at the LBL Bevalac, some of the cross sections of interest can be measured at energies close to those of the cosmic ray nuclei being observed.

  4. Mechanism of heavy ion fusion to superheavy nuclei

    NASA Astrophysics Data System (ADS)

    Adamian, Gurgen G.; Antonenko, Nikolai V.; Scheid, Werner

    2011-10-01

    This article reviews different models for the description of fusion of heavy ions to superheavy nuclei by using adiabatic and diabatic potentials. The dynamics of fusion is basically different in the two types of models for fusion: In the adiabatic models the nuclei melt together, whereas in the diabatic models the nuclei transfer nucleons between each other up to the instant when the compound nucleus is formed. As final result we state that diabatic potentials seem more appropriate for the description of fusion of heavy nuclei than adiabatic potentials.

  5. Reactions of synthesis of heavy nuclei: Brief summary and outlook

    SciTech Connect

    Oganessian, Yu. Ts.

    2006-06-15

    The possible reactions of synthesis of extremely heavy nuclei with almost closed proton and neutron shells are analyzed on the basis of current experimental and theoretical data on the properties of the isotopes of superheavy elements. It has been shown that advances in obtaining extremely heavy nuclei for which microscopic models predict an increase in stability require further investigations of the mechanism of synthesis reactions. Direct and model experiments aimed at solving this problem are discussed.

  6. Analytic expressions for {alpha} particle preformation in heavy nuclei

    SciTech Connect

    Zhang, H. F.; Wang, Y. J.; Dong, J. M.; Royer, G.

    2009-11-15

    Experimental {alpha} decay energies and half-lives are investigated systematically to extract {alpha} particle preformation in heavy nuclei. Formulas for the preformation factors are proposed that can be used to guide microscopic studies on preformation factors and perform accurate calculations of the {alpha} decay half-lives. There is little evidence for the existence of an island of long stability of superheavy nuclei.

  7. Interactions of heavy nuclei, Kr, Xe and Ho, in light targets

    NASA Technical Reports Server (NTRS)

    Kertzman, M. P.; Klarmann, J.; Newport, B. J.; Stone, E. C.; Waddington, C. J.; Binns, W. R.; Garrard, T. L.; Israel, M. H.

    1985-01-01

    Over the past few years, the HEAO-3 measurements of the abundances of ultra-heavy cosmic ray nuclei (Z 26) at earth have been analyzed. In order to interpret these abundances in terms of a source composition, allowance must be made for the propagation of the nuclei in the interstellar medium. Vital to any calculation of the propagation is a knowlege of the total and partial interaction cross sections for these heavy nuclei on hydrogen. Until recently, data on such reactions have been scarce. However, now that relativistic heavy ion beams are available at the LBL Bevalac, some of the cross sections of interest can be measured at energies close to those of the cosmic ray nuclei being observed. During a recent calibration at the Bevalac of an array similar to the HEAO-C3 UH-nuclei detector, targets of raphite (C), polyethylene (CH2), and aluminum were exposed to five heavy ion beams ranging in charge (Z) from 36 to 92. Total and partial charge changing cross sections for the various beam nuclei on hydrogen can be determined from the measured cross sections on C and CH2, and will be applied to the propagation problem. The cross sections on Al can be used to correct the abundances of UH cosmic rays observed in the HEAO C-3 detector for interactions in the detector itself.

  8. Bose condensation of nuclei in heavy ion collisions

    NASA Technical Reports Server (NTRS)

    Tripathi, Ram K.; Townsend, Lawrence W.

    1994-01-01

    Using a fully self-consistent quantum statistical model, we demonstrate the possibility of Bose condensation of nuclei in heavy ion collisions. The most favorable conditions of high densities and low temperatures are usually associated with astrophysical processes and may be difficult to achieve in heavy ion collisions. Nonetheless, some suggestions for the possible experimental verification of the existence of this phenomenon are made.

  9. The response of ionization chambers to relativistic heavy nuclei

    NASA Technical Reports Server (NTRS)

    Newport, B. J.; Stone, E. C.; Waddington, C. J.; Binns, W. R.; Fixsen, D. J.; Garrard, T. L.; Grimm, G.; Israel, M. H.; Klarmann, J.

    1985-01-01

    The LBL Bevalac for the Heavy Nuclei Experiment on HEAO-3, compared the response of a set of laboratory ionization chambers to beams of 26Fe, 36Kr, 54Xe, 67 Ho, and 79Au nuclei at maximum energies ranging from 1666 MeV/amu for Fe to 1049 MeV/amu for Au. The response of these chambers shows a significant deviation from the expected energy dependence, but only a slight deviation from Z sq scaling.

  10. Formation of Heavy and Superheavy Neutron Rich Nuclei

    SciTech Connect

    Zagrebaev, Valery; Greiner, Walter

    2010-04-30

    A new way is proposed to discover and examine unknown neutron-rich heavy and superheavy nuclei at the 'north-east' part of the nuclear map. The present limits of the upper part of the nuclear map is very close to stability while the unexplored area of heavy neutron-rich nuclides to the east of the stability line (also those located along the neutron closed shell N = 126) is extremely important for nuclear astrophysics investigations and for the understanding of the r-process of astrophysical nucleo-genesis. A novel idea is proposed for the production of these nuclei via low-energy multi-nucleon transfer reactions using a gain given by the shell effects. This finding may spur new studies at heavy ion facilities and should have significant impact for future experiments. The use of the multi-nucleon transfer reactions in low-energy collisions of heavy actinide nuclei gives us also the only chance to approach the 'island of stability' of superheavy elements. A possibility for a three-body decay (heavy ternary fission) is predicted for superheavy nuclei.

  11. Bose condensation of nuclei in heavy ion collisions.

    PubMed

    Tripathi, R K; Townsend, L W

    1994-07-01

    Using a fully self-consistent quantum statistical model, we demonstrate the possibility of Bose condensation of nuclei in heavy ion collisions. The most favorable conditions of high densities and low temperatures are usually associated with astrophysical processes and may be difficult to achieve in heavy ion collisions. Nonetheless, some suggestions for the possible experimental verification of the existence of this phenomenon are made. PMID:9969695

  12. Recent studies of heavy nuclei far from stability at JYFL

    SciTech Connect

    Julin, R.; Enqvist, T.; Helariutta, K.

    1996-12-31

    The new K=130 Cyclotron + ECR facility of the Physics Department of the University of Jyvaskyla (JYFL) provides stable beams from protons up to krypton ions for nuclear structure studies. Two instruments designed especially for in-beam spectroscopic studies of heavy nuclei at JYFL are introduced in this contribution. Some results from recent measurements with them are reported.

  13. A Semi-microscopic Approach to Clusterization in Heavy Nuclei

    SciTech Connect

    Darai, J.; Cseh, J.; Antonenko, N. V.; Jolos, R. V.; Algora, A.; Hess, P. O.; Scheid, W.

    2009-08-26

    We present a semimicroscopic approach to clusterization in heavy nuclei. The method is largely based on symmetry-considerations. As an example we determine the possible binary clusterizations of the shape isomers of the {sup 56}Ni nucleus. We combine our structure-considerations with energy-calculations.

  14. Radiative corrections to high energy lepton bremsstrahlung on heavy nuclei

    NASA Astrophysics Data System (ADS)

    Arbuzov, Andrej B.

    2008-01-01

    One-loop radiative corrections to the leptonic tensor in high energy bremsstrahlung on heavy nuclei are calculated. Virtual and real photon radiation is taken into account. Double bremsstrahlung is simulated by means of Monte Carlo. Numerical results are presented for the case of muon bremsstrahlung in conditions of the COMPASS experiment at CERN.

  15. Properties of heavy and superheavy nuclei in supernova environments

    SciTech Connect

    Buervenich, T. J.; Mishustin, I. N.; Greiner, W.

    2008-05-12

    The properties of nuclei embedded in an electron gas are studied within the relativistic mean-field approach. These studies are relevant for nuclear properties in astrophysical environments such as neutron-star crusts and supernova explosions. The electron gas is treated as a constant background in the Wigner-Seitz cell approximation. We investigate the stability of nuclei with respect to {alpha} and {beta} decay. We find that the presence of the electrons leads to stabilizing effects for {alpha} decay at high electron densities. Furthermore, the screening effect shifts the proton dripline to more proton-rich nuclei, and the stability line with respect to {beta}-decay is shifted to more neutron-rich nuclei. Implications for the creation and survival of very heavy nuclear systems are discussed.

  16. The Heavy Nuclei eXplorer (HNX) Small Explorer Mission

    NASA Astrophysics Data System (ADS)

    Mitchell, John; Binns, W. Robert; Hams, Thomas; Israel, Martin; Krizmanic, John; Link, Jason; Rauch, Brian; Sakai, Kenichi; Sasaki, Makoto; Westphal, Andrew; Wiedenbeck, Mark; Heavy Nuclei eXplorer Collaboration

    2015-04-01

    The Heavy Nuclei eXplorer (HNX) will investigate the nature of the reservoirs of nuclei at the cosmic-ray sources, the mechanisms by which nuclei are removed from the reservoirs and injected into the cosmic accelerators, and the acceleration mechanism. HNX will use two large high-precision instruments, the Extremely-heavy Cosmic-ray Composition Observer (ECCO) and the Cosmic-ray Trans-Iron Galactic Element Recorder (CosmicTIGER), flying in the SpaceX DragonLab, to measure, for the first time, the abundance of every individual element in the periodic table from carbon through the actinides, providing the first measurement of many of these elements. HNX will measure several thousand ultra-heavy galactic cosmic ray (UHGCR) nuclei Z >= 30, including about 50 actinides, and will: determine whether GCRs are accelerated from new or old material, and find their age; measure the mix of nucleosynthesis processes responsible for the UHGCRs; determine how UHGCR elements are selected for acceleration, and measure the mean integrated pathlength traversed by UHGCRs before observation. The scientific motivation and instrument complement of HNX will be discussed.

  17. The response of ionization chambers to relativistic heavy nuclei

    NASA Technical Reports Server (NTRS)

    Newport, B. J.; Stone, E. C.; Waddington, C. J.; Binns, W. R.; Fixsen, D. J.; Garrard, T. L.; Grimm, G.; Israel, M. H.; Klarmann, J.

    1985-01-01

    As part of a recent calibration at the LBL Bevalac for the Heavy Nuclei Experiment on HEAO-3, the response of a set of laboratory ionization chambers were compared to beams of 26Fe, 36 Kr, 54Xe, 67 Ho, and 79 Au nuclei at maximum energies ranging from 1666 MeV/amu for Fe to 1049 MeV/amu for Au. The response of these chambers shows a significant deviation from the expected energy dependence, but only a slight deviation from Z squared scaling.

  18. Quantum effects in low-energy photofission of heavy nuclei

    SciTech Connect

    Tsipenyuk, Y.M.; Ostapenko, Y.B.; Smirenkin, G.N.; Soldatov, A.S.

    1984-09-01

    The article is devoted to quantum effects in highly deformed nuclei and the related features of the fission mechanism in the low-energy photofission of heavy nuclei. The following questions are considered: the spectrum of transition states (fission channels), the symmetry of the nuclear configuration in the deformation process, the features of the passage through the barrier due to the existence in the second well of quasistationary states of fissile and nonfissile modes, the isomeric-shelf phenomenon in deep sub-barrier fission, and the relation between the fragment mass distribution and the structure of the fission barrier.

  19. Medium Modification of the Light Vector Mesons in Nuclei

    SciTech Connect

    Nasseripour, R.; Djalali, C.; Wood, M.; Weygand, D.

    2008-10-13

    Theoretical calculations predict the modification of properties of vector mesons, such as a shift in their masses and/or broadening of their widths in dense nuclear matter. These effects can be related to partial restoration of chiral symmetry at high density or temperature. Photoproduction of vector mesons off nuclei were performed at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). The data were taken with a beam of tagged photons with energies up to 4 GeV on various nuclear targets. The properties of the {rho} vector mesons were investigated via their rare leptonic decay to e+e{sup -}. This decay channel is preferred over hadronic modes in order to eliminate final state interactions in the nuclear matter. The combinatorial background in the mass spectrum was removed by a self-normalizing mixed-event technique. The {rho} meson mass distributions were extracted for each of the targets. Statistically significant results regarding medium modification of the rho meson in the nuclear medium rule out large medium effects. Transparency studies of the {omega} and {phi} vector mesons allows a determination of their widths in the medium.

  20. Capabilities of the LDEF-2 heavy nuclei collection

    NASA Technical Reports Server (NTRS)

    Drach, J.; Price, P. B.; Salamon, M. H.; Tarle, G.; Ahlen, S. P.

    1985-01-01

    To take the next big step beyond High Energy Astronomy Observatory (HEAO-3) the Heavy Nuclei Collector (HNC), to be carried on an LDEF reflight, has the goals of greatly increased collecting power ( 30 actinides) and charge resolution sigma sub Z or = 0.25 E for Z up to approximately 100, which will provide abundances of all the charges 40 or Z or = 96 and permit sensitive searches for hypothetical particles such as monopoles, superheavy elements, and quark nuggets.

  1. Comparison of Muon Capture in Light and in Heavy Nuclei

    SciTech Connect

    Measday, David F.; Stocki, Trevor J.

    2007-10-26

    We have recently completed an experimental study at TRIUMF of muon capture in the following elements, N, Al, Si, Ca, Fe, Ni, I, Au, and Bi. We detected the nuclear gamma rays emitted by the product nuclei after muon capture. The energy of the gamma ray identifies the source nuclide, and thus the reaction which has occurred. Our data are of better quality, and more comprehensive than any other data set in the literature. The ({mu}{sup -},{nu}n) reaction is always dominant. In light nuclei, reactions such as ({mu}{sup -},{nu}p) and ({mu}{sup -},{nu}pn) can occur, but not for heavy nuclei. However the reverse is true for reactions such as ({mu}{sup -},{nu}3n) and ({mu}{sup -},{nu}4n), which are very rare in light nuclei, but easily detected in heavy elements. We shall discuss how such information can be useful in calculations of neutrino-nucleus interactions, and of electron-capture in supernovae.

  2. Post-launch analysis of data from the High Energy Astrophysical Observatory Heavy Nuclei Experiment (HEAO-C3)

    NASA Technical Reports Server (NTRS)

    Stone, E. C.

    1992-01-01

    The Final Report on the continuing analysis of data from the Heavy Nuclei Experiment (HNE), flown on the HEAO-3 mission, is presented. The HNE was designed to measure the elemental abundances of relativistic cosmic ray nuclei covering the charge range 17 is less than or equal to Z is less than or equal to 130. The result of these measurements is significant to the study of nucleosynthesis, the origin, acceleration, and propagation of cosmic ray nuclei, and the properties of the interstellar medium.

  3. The Heavy Nuclei eXplorer (HNX) Mission

    NASA Astrophysics Data System (ADS)

    Krizmanic, John; Mitchell, John; Binns, W. Robert; Hams, Thomas; Israel, Martin; Link, Jason; Rauch, Brian; Sakai, Kenichi; Sasaki, Makoto; Westphal, Andrew; Wiedenbeck, Mark; Heavy Nuclei eXplorer Collaboration

    2016-03-01

    The Heavy Nuclei eXplorer (HNX) will use two large high-precision instruments, the Extremely-heavy Cosmic-ray Composition Observer (ECCO) and the Cosmic-ray Trans-Iron Galactic Element Recorder (CosmicTIGER), designed to fly in a SpaceX DragonLab Capsule, to measure the cosmic-ray abundance of every individual element in the periodic table from carbon through curium, providing the first measurement of many of these elements. These measurements provide an investigation on the nature of the source material of cosmic rays, the processes that inject them into cosmic accelerators, and the acceleration mechanisms. HNX will measure several thousand ultra-heavy galactic cosmic ray (UHGCR) nuclei with Z >= 30 , including about 50 actinides (Z >= 79). These data allow for a measurement of the mix of new and old material that is accelerated to GCRs, determine their age, measure the mix of nucleosynthesis processes responsible for the UHGCRs, determine how UHGCR elements are selected for acceleration, and measure the mean integrated pathlength traversed by UHGCRs before observation. The scientific motivation and instrumentation of HNX will be discussed as well as recent beam test results.

  4. Delta excitations in heavy nuclei induced by (3He,t) and (p,n) reactions

    NASA Astrophysics Data System (ADS)

    Esbensen, H.; Lee, T.-S. H.

    1985-12-01

    Delta excitations in heavy nuclei, induced by charge exchange reactions, are studied using the surface response model. The residual pion-exchange interaction and the self-energy of the delta in a nuclear medium is included in the random-phase-approximation response. The peak position observed in (3He,t) reactions can be explained by the self-energy of the delta extracted from pion-nucleus scattering, and the magnitude of the cross section is consistent with Glauber theory. The comparison to (p,n) data is reasonable; contributions from neutron decay of the delta, which are left out in the calculations, constitute a substantial experimental background.

  5. Fusion and fission of heavy and superheavy nuclei (experiment)

    NASA Astrophysics Data System (ADS)

    Itkis, M. G.; Vardaci, E.; Itkis, I. M.; Knyazheva, G. N.; Kozulin, E. M.

    2015-12-01

    The scope of this review is to summarize the main advancements in the search of signatures of the compound nucleus fission and quasifission processes in heavy and superheavy systems. The understanding of fusion and fission in heavy and superheavy elements is needed for tracing paths aimed at reaching the island of stability situated near Z = 114- 122 and N = 184. With increasing charge of the interacting nuclei other processes, like quasifission, emerge and compete against fusion. Hence also their study must be pursued. After a brief look at the experimental techniques, the behavior of several observables is extracted from the most recent data to aid in the disentanglement of the various competing processes which hinder the production of superheavy elements.

  6. Medium Modification of the Light Vector Mesons in Nuclei

    SciTech Connect

    Nasseripour, Rakhsha; Djalali, Chaden; Wood, Michael; Weygand, Dennis

    2008-11-01

    Theoretical calculations predict the modification of properties of vector mesons, such as a shift in their masses and/or broadening of their widths in dense nuclear matter. These effects can be related to partial restoration of chiral symmetry at high density or temperature. Photoproduction of vector mesons off nuclei were performed at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). The data were taken with a beam of tagged photons with energies up to 4 GeV on various nuclear targets. The properties of the rho vector mesons were investigated via their rare leptonic decay to e+e?. This decay channel is preferred over hadronic modes in order to eliminate final state interactions in the nuclear matter. The combinatorial background in the mass spectrum was removed by a self-normalizing mixed-event technique. The rho meson mass distributions were extracted for each of the targets. Statistically significant results regarding medium modification of the rho meson in the nuc

  7. Application of JAERI quantum molecular dynamics model for collisions of heavy nuclei

    NASA Astrophysics Data System (ADS)

    Ogawa, Tatsuhiko; Hashimoto, Shintaro; Sato, Tatsuhiko; Niita, Koji

    2016-06-01

    The quantum molecular dynamics (QMD) model incorporated into the general-purpose radiation transport code PHITS was revised for accurate prediction of fragment yields in peripheral collisions. For more accurate simulation of peripheral collisions, stability of the nuclei at their ground state was improved and the algorithm to reject invalid events was modified. In-medium correction on nucleon-nucleon cross sections was also considered. To clarify the effect of this improvement on fragmentation of heavy nuclei, the new QMD model coupled with a statistical decay model was used to calculate fragment production cross sections of Ag and Au targets and compared with the data of earlier measurement. It is shown that the revised version can predict cross section more accurately.

  8. Isospin dependence of fragment spectra in heavy/super-heavy colliding nuclei at intermediate energies

    NASA Astrophysics Data System (ADS)

    Chugh, Rajiv; Kumar, Rohit; Vinayak, Karan Singh

    2016-05-01

    Using isospin-dependent quantum molecular dynamics (IQMD) approach, we performed a theoretical investigation of the evolution of various kinds of fragments in heavy and superheavy-ion reactions in the intermediate/medium energy domain. We demonstrated direct impact of symmetry energy and Coulomb interactions on the evolution of fragments. Final fragment spectra (yields) obtained from the analysis of various heavy/super-heavy ion reactions at different reaction conditions show high sensitivity towards Coulomb interactions and less significant sensitivity to symmetry energy forms. No inconsistent pattern of fragment structure is obtained in case of super-heavy ion involved reactions for all the parameterizations of density dependence of symmetry energy.

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

    NASA Astrophysics Data System (ADS)

    Hofmann, S.; Heinz, S.; Mann, R.; Maurer, J.; Münzenberg, G.; Antalic, S.; Barth, W.; Dahl, L.; Eberhardt, K.; Grzywacz, R.; Hamilton, J. H.; Henderson, R. A.; Kenneally, J. M.; Kindler, B.; Kojouharov, I.; Lang, R.; Lommel, B.; Miernik, K.; Miller, D.; Moody, K. J.; Morita, K.; Nishio, K.; Popeko, A. G.; Roberto, J. B.; Runke, J.; Rykaczewski, K. P.; Scheidenberger, C.; Shaughnessy, D. A.; Stoyer, M. A.; Thörle-Pospiech, P.; Tinschert, K.; Trautmann, N.; Uusitalo, J.; Yeremin, A. V.

    2016-04-01

    Shell-correction energies of super-heavy nuclei are approximated by using Q_{α} values of measured decay chains. Five decay chains were analyzed, which start at the isotopes 285Fl, 294118, 291Lv, 292Lv and 293Lv. 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.

  10. Charmed Mesons in Nuclei with Heavy-Quark Spin Symmetry

    NASA Astrophysics Data System (ADS)

    Tolos, L.; Garcia-Recio, C.; Nieves, J.; Romanets, O.; Salcedo, L. L.

    2013-08-01

    We study the properties of charmed pseudoscalar and vector mesons in dense matter within a unitary meson-baryon coupled-channel model which incorporates heavy-quark spin symmetry. This is accomplished by extending the SU(3) Weinberg-Tomozawa Lagrangian to incorporate spin-flavor symmetry and implement a suitable flavor symmetry breaking. Several resonances with negative parity are generated dynamically by the s-wave interaction between pseudoscalar and vector meson multiplets with 1/2+ and 3/2+ baryons. Those states are then compared to experimental data as well as theoretical models. Next, Pauli-blocking effects and meson self-energies are introduced in a self-consistent manner to obtain the open-charm meson spectral functions in a dense nuclear environment. We finally discuss the formation of D-mesic nuclei.

  11. Strictly finite-range potential for light and heavy nuclei

    NASA Astrophysics Data System (ADS)

    Salamon, P.; Lovas, R. G.; Betan, R. M. Id; Vertse, T.; Balkay, L.

    2014-05-01

    Strictly finite-range (SFR) potentials are exactly zero beyond their finite range. Single-particle energies and densities, as well as S-matrix pole trajectories, are studied in a few SFR potentials suited for the description of neutrons interacting with light and heavy nuclei. The SFR potentials considered are the standard cutoff Woods-Saxon (CWS) potentials and two potentials approaching zero smoothly: the SV potential introduced by Salamon and Vertse [Phys. Rev. C 77, 037302 (2008), 10.1103/PhysRevC.77.037302] and the SS potential of Sahu and Sahu [Int. J. Mod. Phys. E 21, 1250067 (2012), 10.1142/S021830131250067X]. The parameters of these latter potentials were set so that the potentials may be similar to the CWS shape. The range of the SV and SS potentials scales with the cube root of the mass number of the core like the nuclear radius itself. For light nuclei a single term of the SV potential (with a single parameter) is enough for a good description of the neutron-nucleus interaction. The trajectories are compared with a benchmark for which the starting points (belonging to potential depth zero) can be determined independently. Even the CWS potential is found to conform to this benchmark if the range is identified with the cutoff radius. For the CWS potentials some trajectories show irregular shapes, while for the SV and SS potentials all trajectories behave regularly.

  12. Secondary electron background produced by heavy nuclei in a multiwire proportional counter hodoscope

    NASA Technical Reports Server (NTRS)

    Morgan, S. H., Jr.; Watts, J. W., Jr.; Schwille, H.; Pollvogt, U.

    1974-01-01

    The secondary electron background produced by heavy nuclei in a multiwire proportional counter hodoscope is calculated using both a simplified and a more complete Monte Carlo model. These results are compared with experimental data from a small multiwire proportional counter hodoscope operated in a 530 MeV/nucleon accelerator beam of nitrogen nuclei. Estimates of the secondary electron background produced by heavy relativistic nuclei are presented along with the detailed results from calculations of energy deposition in the hodoscope counter cells.

  13. Studies of heavy-ion reactions and transuranic nuclei

    NASA Astrophysics Data System (ADS)

    Schroeder, W. U.

    1993-08-01

    Papers on the following topics are included: The Cold-Fusion Saga; Decay Patterns of Dysprosium Nuclei Produced in S-32 + Sn-118,124 Fusion Reactions; Unexpected Features of Reactions Between Very Heavy Ions at Intermediate Bombarding Energies; Correlations Between Neutrons and Charged Products from the Dissipative Reaction Au-197 + Pb-208 at E/A = 29 MeV; Dissipative Dynamics of Projectile-Like Fragment Production in the Reaction Bi-209 + Xe-136 at E/A = 28.2 MeV; Dynamical Production of Intermediate-Mass Fragments in Peripheral Bi-209 + Xe-136 Collisions at E(sub lab)/A = 28.2 MeV; The Rochester 960-Liter Neutron Multiplicity Meter; A Simple Pulse Processing Concept for a Low-Cost Pulse-Shape-Based Particle Identification; A One-Transistor Preamplifier for PMT Anode Signals; A Five-Channel Multistop TDC/Event Handler for the SuperBall Neutron Multiplicity Meter; Construction of the SuperBall - a 16,000-Liter Neutron Detector for Calorimetric Studies of Intermediate-Energy Heavy-Ion Reactions; A Computer Code for Light Detection Efficiency Calculations for Photo-multipliers of a Neutron Detector; Evaluation of Gd-Loaded Liquid Scintillators for the SuperBall Neutron Calorimeter; and Measurement of the Interaction of Cosmic-Ray mu(-) with a Muon Telescope.

  14. Nuclear isospin asymmetry in α decay of heavy nuclei

    NASA Astrophysics Data System (ADS)

    Shin, Eunkyoung; Lim, Yeunhwan; Hyun, Chang Ho; Oh, Yongseok

    2016-08-01

    The effects of nuclear isospin asymmetry on α -decay lifetimes of heavy nuclei are investigated within various phenomenological models of the nuclear potential for the α particle. We consider the widely used simple square-well potential and Woods-Saxon potential and modify them by including an isospin asymmetry term. We then suggest a model for the potential of the α particle motivated by a microscopic phenomenological approach of the Skyrme force model, which naturally introduces the isospin-dependent form of the nuclear potential for the α particle. The empirical α -decay lifetime formula of Viola and Seaborg [J. Inorg. Nucl. Chem. 28, 741 (1966), 10.1016/0022-1902(66)80412-8] is also modified to include isospin asymmetry effects. The obtained α -decay half-lives are in good agreement with the experimental data, and we find that including the nuclear isospin effects somehow improves the theoretical results for α -decay half-lives. The implications of these results are discussed, and the predictions on the α -decay lifetimes of superheavy elements are also presented.

  15. Survival of high p{sub T} light and heavy flavors in a dense medium

    SciTech Connect

    Kopeliovich, B. Z.

    2011-04-26

    This talk presents an attempt at a critical overview of the current status of modeling for high-p{sub T} processes in nuclei. In particular, it includes discussion of the space-time development of hadronization of highly virtual light and heavy partons, and the related time scales; the role of early production and subsequent attenuation of pre-hadrons in a dense medium. We identify several challenging problems within the current interpretation of high-p{sub T} processes and propose solutions for some of them.

  16. Super-Heavy Element and Other Exotic Nuclei Research at LLNL

    NASA Astrophysics Data System (ADS)

    Stoyer, M. A.

    2015-11-01

    The experimental nuclear physics group at LLNL is actively investigating exotic nuclei in a variety of regions of the chart of nuclides - from light nuclei to super-heavy elements. The experimental nuclear physics effort at LLNL is centered on investigating nuclei at the extremes--in particular, extremes of spin, isospin, neutron richness, excitation energy, decay and detectability, mass, and stability. This talk will focus on recent heavy and super-heavy element experiments including nuclear structure investigations of the heaviest nuclei. Other areas of research, including radioactive ion beam experiments, trapping experiments, nuclear decay spectroscopy experiments, and rare decay searches, will be discussed as time permits. Recent experimental results on studies of exotic nuclei by scientists at LLNL will be presented.

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

    NASA Astrophysics Data System (ADS)

    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.

  18. Monte Carlo Simulation of Heavy Nuclei Photofission at Intermediate Energies

    SciTech Connect

    Andrade-II, E.; Freitas, E.; Garcia, F.; Tavares, O. A. P.; Duarte, S. B.

    2009-06-03

    A detailed description of photofission process at intermediate energies (200 to 1000 MeV) is presented. The study of the reaction is performed by a Monte Carlo method which allows the investigation of properties of residual nuclei and fissioning nuclei. The information obtained indicate that multifragmentation is negligible at the photon energies studied here, and that the symmetrical fission is dominant. Energy and mass distributions of residual and fissioning nuclei were calculated.

  19. Study of Analytic Statistical Model for Decay of Light and Medium Mass Nuclei in Nuclear Fragmentation

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.; Wilson, John W.

    1996-01-01

    The angular momentum independent statistical decay model is often applied using a Monte-Carlo simulation to describe the decay of prefragment nuclei in heavy ion reactions. This paper presents an analytical approach to the decay problem of nuclei with mass number less than 60, which is important for galactic cosmic ray (GCR) studies. This decay problem of nuclei with mass number less than 60 incorporates well-known levels of the lightest nuclei (A less than 11) to improve convergence and accuracy. A sensitivity study of the model level density function is used to determine the impact on mass and charge distributions in nuclear fragmentation. This angular momentum independent statistical decay model also describes the momentum and energy distribution of emitted particles (n, p, d, t, h, and a) from a prefragment nucleus.

  20. Medium and Heavy Duty Vehicle Field Evaluations (Presentation)

    SciTech Connect

    Walkowicz, K.

    2014-06-01

    This presentation discusses field evaluations of medium- and heavy-duty vehicles performed by NREL. The project provides medium-duty (MD) and heavy-duty (HD) test results, aggregated data, and detailed analysis, including 3rd party unbiased data (data that would not normally be shared by industry in an aggregated and detailed manner). Over 5.6 million miles of advanced technology MD and HD truck data have been collected, documented, and analyzed on over 240 different vehicles since 2002. Data, analysis, and reports are shared within DOE, national laboratory partners, and industry for R&D planning and strategy. The results help guide R&D for new technology development, help define intelligent usage of newly developed technology, and help fleets/users understand all aspects of advanced technology.

  1. A variational Monte Carlo approach for the study of medium-mass nuclei

    NASA Astrophysics Data System (ADS)

    Lonardoni, Diego; Pieper, Steven C.; Wiringa, Robert B.; Lovato, Alessandro

    2015-10-01

    We report on an accurate variational many-body technique (cluster variational Monte Carlo) suitable for the study of medium-mass nuclei. The employed many-body nuclear Hamiltonian contains realistic two- and three-nucleon interactions and the trial wave function is constructed from pair- and triplet-correlation operators acting on a product of single-particle determinants. As opposed to traditional variational Monte Carlo calculations, that are limited to A = 12 nuclei, expectation values are evaluated with a cluster expansion for the non-central correlations. The cluster expansion drastically reduces the computational effort necessary for the study of an A-body system, allowing us to extend the calculations in the medium-mass region, currently up to 40 nucleons. We present results for the closed-shell nuclei 16O and 40Ca and prospects for open-shell nuclei like 40Ar. Of particular interest is the derivation of the momentum distributions that can be used to constrain the spectral functions of these nuclei. This has a crucial interplay with electron-nucleon and neutrino-nucleon scattering experiments, where Argon is among the typical targets and the scattering data at high momentum transfer can be analyzed by means of the spectral function formalism. This work is supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under the NUCLEI SciDAC grant and Contract No. DE-AC02-06CH11357.

  2. Heavy nuclei confinement effect in a pulsed light field

    NASA Astrophysics Data System (ADS)

    Starodub, S. S.; Roshchupkin, S. P.

    2011-04-01

    It is a model theoretical work of the applied character in which: "Outside the framework of the dipole approximation (with an accuracy of about v/c) the effective interaction force between stripped uranium nuclei in the presence pulsed field of two laser waves extending towards each other is theoretically studied. It is shown that the effective interaction force between uranium nuclei, can become an attractive force on certain time intervals in the presence of the pulsed laser field. As a result the pulsed laser field can slow down backward motion of nuclei in 7 times."

  3. MCNP6 simulation of light and medium nuclei fragmentation at intermediate energies

    NASA Astrophysics Data System (ADS)

    Mashnik, Stepan G.; Kerby, Leslie M.

    2016-05-01

    Fragmentation reactions induced on light and medium nuclei by protons and light nuclei of energies around 1 GeV/nucleon and below are studied with the Los Alamos transport code MCNP6 and with its CEM03.03 and LAQGSM03.03 event generators. CEM and LAQGSM assume that intermediate-energy fragmentation reactions on light nuclei occur generally in two stages. The first stage is the intranuclear cascade (INC), followed by the second, Fermi breakup disintegration of light excited residual nuclei produced after the INC. CEM and LAQGSM account also for coalescence of light fragments (complex particles) up to 4He from energetic nucleons emitted during INC. We investigate the validity and performance of MCNP6, CEM, and LAQGSM in simulating fragmentation reactions at intermediate energies and discuss possible ways of further improving these codes.

  4. MCNP6 Simulation of Light and Medium Nuclei Fragmentation at Intermediate Energies

    SciTech Connect

    Mashnik, Stepan Georgievich; Kerby, Leslie Marie

    2015-08-24

    Fragmentation reactions induced on light and medium nuclei by protons and light nuclei of energies around 1 GeV/nucleon and below are studied with the Los Alamos transport code MCNP6 and with its CEM03.03 and LAQGSM03.03 event generators. CEM and LAQGSM assume that intermediate-energy fragmentation reactions on light nuclei occur generally in two stages. The first stage is the intranuclear cascade (INC), followed by the second, Fermi breakup disintegration of light excited residual nuclei produced after the INC. CEM and LAQGSM account also for coalescence of light fragments (complex particles) up to sup>4He from energetic nucleons emitted during INC. We investigate the validity and performance of MCNP6, CEM, and LAQGSM in simulating fragmentation reactions at intermediate energies and discuss possible ways of further improving these codes.

  5. Introduction to the study of collisions between heavy nuclei

    SciTech Connect

    Bayman, B.F.

    1980-01-01

    Current investigations concerning the collisions of nuclei governed by small de Broglie wavelengths are reviewed. The wave packets localize nuclei in regions small compared to their diameters. Cross sections are examined for potential scattering, elastic scattering, quasi-molecular states, peripheral particle-transfer reactions, fusion, and deep inelastic collisions. Theories of fusion and deep inelastic collisions are summarized. This paper is in the nature of a review-tutorial. 45 references, 51 figures, 2 tables. (RWR)

  6. Light nuclei production in fusion of heavy ions

    SciTech Connect

    Antonenko, N.V.; Ivanova, S.P.; Jolos, R.V.; Scheid, W. Joint Institute for Nuclear Research, 141980 Dubna )

    1994-10-01

    A possible mechanism of the production of light nuclei in fusion reactions is considered. It is shown that the decay of the dinuclear system during its evolution to a compound nucleus yields a substantial rate for the production of light nuclei. The cross section of this process is calculated for the reaction [sup 58]Ni+[sup 58]Ni. The coupling of other modes of motion causes an increase of the asymmetric decay of the dinuclear system.

  7. The Heavy Nuclei eXplorer (HNX) Mission

    NASA Technical Reports Server (NTRS)

    Binns, W. R.; Adams, J. H.; Barbier, L. M.; Craig, N.; Cummings, A. C.; Cummings, J. R.; Doke, T.; Hasebe, N.; Hayashi, T.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    The primary scientific objectives of HNX, which was recently selected by NASA for a Small Explorer (SMEX) Mission Concept Study, are to measure the age of the galactic cosmic rays (GCR) since nucleosynthesis, determine the injection mechanism for the GCR accelerator (Volatility or FIP), and study the mix of nucleosynthetic processes that contribute to the source of GCRs. The experimental goal of HNX is to measure the elemental abundances of all individual stable nuclei from neon through the actinides and possibly beyond. HNX is composed of two instruments: ECCO, which measures elemental abundances of nuclei with Z greater than or equal to 72, and ENTICE. which measures elemental abundances of nuclei with Z between 10 and 82. We describe the mission and the science that can be addressed by HNX.

  8. Production of light nuclei in relativistic heavy-ion collisions

    SciTech Connect

    Barrette, J.; Bellwied, R.; Braun-Munzinger, P.; Cleland, W.E.; Cormier, T.M.; David, G.; Dee, J.; Diebold, G.E.; Dietzsch, O.; Germani, J.V.; Gilbert, S.; Greene, S.V.; Hall, J.R.; Hemmick, T.K.; Herrmann, N.; Hong, B.; Jayananda, K.; Kraus, D.; Kumar, B.S.; Lacasse, R.; Lissauer, D.; Llope, W.J.; Ludlam, T.W.; McCorkle, S.; Majka, R.; Mark, S.K.; Mitchell, J.T.; Muthuswamy, M.; O'Brien, E.; Pruneau, C.; Rotondo, F.S.; Sandweiss, J.; daSilva, N.C.; Sonnadara, U.; Stachel, J.; Takai, H.; Takagui, E.M.; Throwe, T.G.; Wolfe, D.; Woody, C.L.; Xu, N.; Zhang, Y.; Zhang, Z.; Zou, C. Gesellschaft fuer Schwerionenforschung, Darmstadt McGill University, Montreal, Canada H3A University of Pittsburgh, Pittsburgh, Pennsylvania 15260 State University of New York, Stony Brook, New York 11794 University of New Mexico, Albuquerque, New Mexico 87131 University of Sa

    1994-08-01

    We have measured cross sections for the synthesis of nuclei of mass [ital A][le]4 in collisions of 14.6[ital A] GeV/[ital c] [sup 28]Si nuclei with targets of Pb, Cu, and Al. The data are measured at close to center-of-mass rapidities, and are unique in their exploration of the centrality dependence of nucleosynthesis. Simple coalescence models that were used to study nucleosynthesis at lower energies are inadequate for the description of our measurements. Our data and improved models are used to extract parameters related to the size of the interaction volume at freeze-out.

  9. The survival of heavy nuclei in cosmic ray source environments

    NASA Technical Reports Server (NTRS)

    Balasubrahmanyan, V. K.

    1972-01-01

    Results from the Goddard balloon spectrometer and the results reported by Soviet scientists using the Proton series of satellites are summarized. The important experimental results from the balloon spectrometer experiment are as follows: (1) On a total-energy scale, protons constitute only a minor proportion of the cosmic rays, only 20 percent. The rest of the cosmic rays are complex nuclei. (2) All the nuclei have the same power low spectrum in total energy and so the composition seems to be independent of energy.

  10. Reactions of Synthesis of Heavy Nuclei Results and Perspectives

    SciTech Connect

    Oganessian, Yu.

    2006-08-14

    The experimental and theoretical results on the properties of the isotopes of superheavy elements, obtained up to now, have made it possible to consider different reactions for the synthesis of heavier nuclei located in the vicinity of the closed proton and neutron shells. It is shown that the advance to the heaviest possible nuclei, for which the microscopic models predict further rise of stability, is inseparably linked to the future investigation of the mechanism of synthesis reactions. Direct and model experiments, aimed at solving this problem, are also discussed.

  11. Neutron flow between nuclei as the principal enhancement mechanism in heavy-ion subbarrier fusion

    SciTech Connect

    Stelson, P.H.

    1988-01-01

    The observed enhanced cross sections for heavy-ion fusion are interpreted with a model in which the near barrier cross sections are dominated by neck formation initiated by neutron flow between the colliding nuclei. The collective properties of the colliding nuclei are then interpreted as a modulation of the thresholds for neck formation and dominate the cross sections in the region far below the barrier. 12 refs., 12 figs., 2 tabs.

  12. Nucleosynthesis of neutron-rich heavy nuclei during explosive helium burning in massive stars

    NASA Technical Reports Server (NTRS)

    Blake, J. B.; Woosley, S. E.; Weaver, T. A.; Schramm, D. N.

    1981-01-01

    The production of heavy nuclei during explosive helium burning has been calculated using a hydrodynamical model of a 15-solar mass (Type II) supernova and an n-process nuclear reaction network. It is found that the resulting neutron-rich heavy nuclei are not produced in the relative abundances of solar-system r-process material, especially in the vicinity of Pt, nor are any actinides produced. These deficiencies reflect an inadequate supply of neutrons. However, some neutron-rich isotopes, normally associated with the r-process, are produced which may be significant for the production of isotopic anomalies in meteorites.

  13. Studies of the Shapes of Heavy Nuclei at ISOLDE

    NASA Astrophysics Data System (ADS)

    Butler, Peter A.

    For certain combinations of protons and neutrons there is a theoretical expectation that the shape of nuclei can assume octupole deformation, which would give rise to reflection asymmetry or a "pear-shape" in the intrinsic frame, either dynamically (octupole vibrations) or statically (permanent octupole deformation). In this talk I will briefly review the historic evidence for reflection asymmetry in nuclei and describe how recent experiments carried out at REX-ISOLDE have constrained nuclear theory and how they contribute to tests of extensions of the Standard Model. I will also discuss future prospects for measuring nuclear shapes from Coulomb Excitation: experiments are being planned that will exploit beams from HIE-ISOLDE that are cooled in the TSR storage ring and injected into a solenoidal spectrometer similar to the HELIOS device developed at the Argonne National Laboratory.

  14. One-quasiparticle states in odd-Z heavy nuclei

    SciTech Connect

    Adamian, G. G.; Antonenko, N. V.; Kuklin, S. N.; Scheid, W.

    2010-11-15

    The isotopic dependencies of one-quasiparticle states in Es and Md are treated. In {sup 253,255}Lr, the energies of the lowest one-quasiproton states are calculated. The one-quasiparticle isomer states are revealed in the nuclei of an {alpha}-decay chain starting from {sup 269}Rg. The {alpha} decays from some isomer states are predicted. The population of isomer states in the complete fusion reactions is discussed.

  15. Measurement of heavy cosmic-ray nuclei on LDEF (M0002-2)

    NASA Technical Reports Server (NTRS)

    Beaujean, R.; Enge, W.; Siegmon, G.

    1984-01-01

    The objective of this experiment is to measure the elemental and isotopic abundamces of heavy cosmic-ray nuclei with nuclear charge Z equal to or greater than 3. The chemical and energy spectra will be measured for particles that have energies in the range from 20 to 1000 MeV per atomic mass unit. Two points of great interest are geomagneticaly forbidden cosmic-ray particles and heavy ions of the trapped radiation.

  16. Glauber Theory for Medium- and High-Energy Reactions of Unstable Nuclei

    SciTech Connect

    Suzuki, Y.

    2009-06-03

    Glauber theory is employed to describe the scattering and reactions induced by unstable nuclei at medium and high energies. Total reaction cross sections of carbon isotopes up to a dripline nucleus {sup 22}C are analyzed systematically using densities constructed phenomenologically. A simple correction is introduced to cure the well-known divergence of the Coulomb breakup cross section in the eikonal approximation, and is applied to a four-body description of {sup 6}He+{sup 208}Pb reaction.

  17. Influence of the nuclear medium on inclusive electron and neutrino scattering off nuclei

    SciTech Connect

    Buss, O.; Leitner, T.; Mosel, U.; Alvarez-Ruso, L.

    2007-09-15

    We present a model for inclusive electron and neutrino scattering off nuclei paying special attention to the influence of in-medium effects on the quasielastic scattering and pion-production mechanisms. Our results for electron scattering off {sup 16}O are compared to experimental data at beam energies ranging from 0.7 to 1.5 GeV. The good description of electron scattering serves as a benchmark for neutrino scattering.

  18. α preformation factors of medium-mass nuclei and the structural effects in the region of crossing the Z =82 shell

    NASA Astrophysics Data System (ADS)

    Deng, Daming; Ren, Zhongzhou

    2016-04-01

    The α preformation factors of medium-mass nuclei as well as their behavior in the vicinity of Z =82 shell closure are systematically investigated by using the cluster-formation model (CFM). The recently proposed CFM was proven to be effective in the evaluation of α preformation factors in the heavy-mass region, and we find that it is also valid for medium-mass nuclei because it reproduces reasonable features of the variation of α preformation probability, especially the Z =82 shell effects which are made evident in a recent experiment. A total of 363 nuclides (including even-even, odd-A and odd-odd nuclei) with 72 ≤Z ≤88 and 84 ≤N ≤117 are included in our calculation. Through a comparison between Z =82 and N =126 shell effects, the structural effects inside the observed different behavior of preformation factors are discussed in detail. As an extended application to medium-mass nuclei, the CFM provides a convenient and effective way to extract nuclear structure information from the α preformation factor. The results in this work can be a useful reference for future analysis in the microscopic calculation of α decay.

  19. The α decay spectroscopic factor of heavy and superheavy nuclei

    NASA Astrophysics Data System (ADS)

    Seif, W. M.

    2013-10-01

    The spectroscopic factor which refers to the preformation probability of an α cluster inside parent radioactive nuclei is investigated. The study is based on the cluster model of α decay that is extended to account for the deformation degrees of freedom. The calculations are carried out for 179 even(Z)-even(N) parent nuclei in the mass region of A = 144-294. Taking into account the deformations of daughter nuclei, the semi-microscopic calculations of the α-daughter interaction potential are performed using the Hamiltonian energy density approach in terms of the SLy4 Skyrme-like effective interaction. The calculated potential is then implemented to find both the assault frequency and the penetration probability of the α particle by means of the Wentzel-Kramers-Brillouin approximation at different orientations of the deformed daughter. By averaging the obtained decay widths over different orientations, the half-lives of the mentioned α decays are then estimated. Taking into account the errors on both the released energy and the experimental half-life times, the extracted half-lives are employed in turn to deduce the α spectroscopic factor. The results show a periodic behaviour of the spectroscopic factor as a function of the charge and neutron numbers characterized by several local maxima and minima. The predicted minima are mainly related to the proton and neutron shell and subshell closures. In addition to the well-known closed shells of the nucleonic numbers 50, 82, and 126, the obtained values of the spectroscopic factor give some evidence for the presence of closed subshells of nucleonic numbers 70, 102 (104) and 152 (150). A simple formula is suggested to roughly estimate the spectroscopic factor in terms of the numbers of protons and neutrons of the parent nucleus outside its closed shells. The parameters of this formula are fitted to the deduced values of the spectroscopic factor.

  20. Symmetries in heavy nuclei and the proton-neutron interaction

    SciTech Connect

    Casten, R.F.

    1986-01-01

    The Interacting Boson Approximation (IBA) nuclear structure model can be expressed in terms of the U(6) group, and thereby leads to three dynamical symmetries (or group chains) corresponding to different nuclear coupling schemes and geometrical shapes. The status of the empirical evidence for these three symmetries is reviewed, along with brief comments on the possible existence of supersymmetries in nuclei. The relationships between these symmetries, the nuclear phase transitional regions linking them, and the residual proton-neutron interaction are discussed in terms of a particularly simple scheme for parameterizing the effects of that interaction. 34 refs., 15 figs.

  1. Manifestation of cluster effects in collective octupole and superdeformed states of heavy nuclei.

    NASA Astrophysics Data System (ADS)

    Shneidman, T. M.; Adamian, G. G.; Antonenko, N. V.; Jolos, R. V.

    2016-06-01

    The effects of reflection-asymmetric deformation on the properties of the low-lying negative-parity collective states and superdeformed states of heavy nuclei are analyzed basing on dinuclear model. The results of consideration of the alternating parity bands in actinides and the superdeformed bands in 60Zn, Pb and Hg isotopes are discussed.

  2. Projected shell model for Gamow-Teller transitions in heavy, deformed nuclei

    NASA Astrophysics Data System (ADS)

    Wang, Long-Jun; Sun, Yang; Gao, Zao-Chun; Kiran Ghorui, Surja

    2016-02-01

    Calculations of Gamow-Teller (GT) transition rates for heavy, deformed nuclei, which are useful input for nuclear astrophysics studies, are usually done with the quasiparticle random-phase approximation. We propose a shell-model method by applying the Projected Shell Model (PSM) based on deformed bases. With this method, it is possible to perform a state-by-state calculation for nuclear matrix elements for β-decay and electron-capture in heavy nuclei. Taking β- decay from 168Dy to 168Ho as an example, we show that the known experimental B(GT) from the ground state of the mother nucleus to the low-lying states of the daughter nucleus could be well described. Moreover, strong transitions to high-lying states are predicted to occur, which may considerably enhance the total decay rates once these nuclei are exposed to hot stellar environments.

  3. Calculations of {alpha}-decay half-lives for heavy and superheavy nuclei

    SciTech Connect

    Qian Yibin; Ni Dongdong; Ren, Zhongzhou

    2011-04-15

    Systematic calculations on the {alpha}-decay half-lives of heavy and superheavy nuclei are performed within a deformed version of the cluster model, using the modified two-potential approach. The deformed Woods-Saxon potential is employed to calculate the {alpha}-decay width through a deformed barrier. For comparison the calculated {alpha}-decay half-lives in the empirical relations are also presented. The present study is initially restricted to even-even nuclei in the heavy mass region with N>126. Then the study is extended to the recently observed heaviest nuclei, including synthesized superheavy elements and isotopes. The {alpha}-decay half-lives obtained are found to be in good agreement with the experimental data.

  4. Detection of ultra rare α decays of super heavy nuclei

    NASA Astrophysics Data System (ADS)

    Tsyganov, Yuri S.

    2007-04-01

    Three approaches to the measurement of a rare α decaying products produced in heavy-ion induced nuclear reactions are described. One is based on a chemical extraction and following deposition of the nuclides under investigation onto the surface of the detector, whereas the second one is associated with long-lived products implanted into silicon detectors by using the electromagnetic separation technique. The third approach relates with an application of real-time mode detection of correlated energy-time-position recoil-α sequences from 48Ca induced nuclear reactions with actinide targets, like 242,244Pu, 245,248Cm, 239Am and 249Cf. Namely with this technique, it has became possible to provide a radical suppression of backgrounds in the full fusion (3-5n) reactions aimed to the synthesis of super heavy elements with Z=113-116.

  5. Proximity potential for heavy ion reactions on deformed nuclei

    SciTech Connect

    Baltz, A. J.; Bayman, B. F.

    1982-01-01

    The usual treatment of the deformed optical model for analysis of heavy ion induced inelastic scattering data involves a deformed (target) radius, a spherical (projectile) radius and a potential strength dependent on the surface separation along the line between the two centers. Several authors using various approaches have shown that this center line potential is geometrically inadequate especially for description of higher L deformation parameters probed in heavy ion induced inelastic scattering experiments. A quantitatively adequate form of the deformed proximity potential suitable for use with a coupled channels reaction code in the analysis of inelastic scattering data above the Coulomb barrier is described. A major objective is to be able to extract reliably higher deformed multipole moments from such data. The deformed potential calculated in the folding model will serve as a geometrically exact benchmark to evaluate the accuracy of the proximity potential prescriptions. (WHK)

  6. The dynamic mathematical model of heavy-medium cyclone

    SciTech Connect

    Xu Jianping

    1997-12-31

    For ascertaining the effect of the various variables during the coal separation process of heavy medium (HM) cyclone, a dynamic mathematical model for simulating the separating process of the HM cyclone has been developed based on data obtained through both laboratory and industrial experiments. As evidenced by the result of study, increase to a certain extent of inlet pressure and media-coal ratio may result in higher separating precision. The effect of rheological property of the suspension is particularly important, and often plays a decisive role in this respect. The research-derived model can either be used for predicting the separating process and performance or for effecting process control of a HM cyclone through simulating its operation.

  7. α-DECAY Properties of Heavy and Superheavy Nuclei

    NASA Astrophysics Data System (ADS)

    Zhang, H. F.

    2013-11-01

    The experimental investigation cannot presently distinguish explicitly whether the α particle is preformed in mother nucleus or it is formed during penetrating of the potential barrier. Consequently, the α-decay has been mainly described using the cluster-like theories and the fission-like theories. In any way, the assault frequency plays a pivotal role in the two different decay modes. A microscopic approach is adopted to estimate the assault frequency and the results are consistent with the assault frequency extracted within the cluster-like model, which suggests that the α-decay is rather a radioactive emission process of a cluster preformed in the nucleus but before the potential barrier penetration. The α-decay half-life are estimated in the framework of the preformed cluster-like model to explore the island of stability of superheavy nuclei.

  8. Spectroscopic factors and cluster decay half-lives of heavy nuclei

    SciTech Connect

    Kuklin, S.N.; Adamian, G.G.; Antonenko, N.V.

    2005-01-01

    The cluster radioactivity is treated under the assumption that the light clusters are produced by a collective motion of the nuclear system in the charge asymmetry coordinate with further penetration through the Coulomb barrier. The known experimental data on cluster radioactivity are described. The half-lives of cluster emission of neutron-deficient actinides and medium-mass nuclei are predicted.

  9. Analysis of quasifission competition in fusion reactions forming heavy nuclei

    NASA Astrophysics Data System (ADS)

    Hammerton, Kalee; Kohley, Zachary; Morrissey, Dave; Wakhle, Aditya; Stiefel, Krystin; Hinde, David; Dasgupta, Mahananda; Williams, Elizabeth; Simenel, Cedric; Carter, Ian; Cook, Kaitlin; Jeung, Dongyun; Luong, Duc Huy; McNeil, Steven; Palshetkar, Chandani; Rafferty, Dominic

    2015-10-01

    Heavy-ion fusion reactions have provided a mechanism for the production of superheavy elements allowing for the extension of both the periodic table and chart of the nuclides. However, fusion of the projectile and target, forming a compound nucleus, is hindered by orders of magnitude by the quasifission process in heavy systems. In order to fully understand this mechanism, and make accurate predictions for superheavy element production cross sections, a clear description of the interplay between the fusion-fission and quasifission reaction channels is necessary. The mass-angle distributions of fragments formed in 8 different Cr + W reactions were measured at the Australia National University in order to explore the N/Z dependence of the quasifission process. Two sets of data were measured: one at a constant energy relative to the fusion barrier and one at a constant compound nucleus excitation energy. The results of this analysis will provide insight into the effect of using more neutron-rich beams in superheavy element production reactions.

  10. NEW EQUATIONS OF STATE BASED ON THE LIQUID DROP MODEL OF HEAVY NUCLEI AND QUANTUM APPROACH TO LIGHT NUCLEI FOR CORE-COLLAPSE SUPERNOVA SIMULATIONS

    SciTech Connect

    Furusawa, Shun; Yamada, Shoichi; Sumiyoshi, Kohsuke; Suzuki, Hideyuki

    2013-08-01

    We construct new equations of state for baryons at subnuclear densities for the use in core-collapse simulations of massive stars. The abundance of various nuclei is obtained together with thermodynamic quantities. A model free energy is constructed, based on the relativistic mean field theory for nucleons and the mass formula for nuclei with the proton number up to {approx}1000. The formulation is an extension of the previous model, in which we adopted the liquid drop model to all nuclei under the nuclear statistical equilibrium. We reformulate the new liquid drop model so that the temperature dependences of bulk energies could be taken into account. Furthermore, we extend the region in the nuclear chart, in which shell effects are included, by using theoretical mass data in addition to experimental ones. We also adopt a quantum-theoretical mass evaluation of light nuclei, which incorporates the Pauli- and self-energy shifts that are not included in the ordinary liquid drop model. The pasta phases for heavy nuclei are taken into account in the same way as in the previous model. We find that the abundances of heavy nuclei are modified by the shell effects of nuclei and temperature dependence of bulk energies. These changes may have an important effect on the rates of electron captures and coherent neutrino scatterings on nuclei in supernova cores. The abundances of light nuclei are also modified by the new mass evaluation, which may affect the heating and cooling rates of supernova cores and shocked envelopes.

  11. Two-neutron transfer reactions with heavy-deformed nuclei

    SciTech Connect

    Price, C.; Landowne, S.; Esbensen, H.

    1988-01-01

    In a recent communication we pointed out that one can combine the macroscopic model for two-particle transfer reactions on deformed nuclei with the sudden limit approximation for rotational excitation, and thereby obtain a practical method for calculating transfer reactions leading to high-spin states. As an example, we presented results for the reaction WSDy(VYNi,WNi) WDy populating the ground-state rotational band up to the spin I = 14 state. We have also tested the validity of the sudden limit for the inelastic excitation of high spin states and we have noted how the macroscopic model may be modified to allow for more microscopic nuclear structure effects in an application to diabolic pair-transfer processes. This paper describes our subsequent work in which we investigated the systematic features of pair-transfer reactions within the macroscopic model by using heavier projectiles to generate higher spins and by decomposing the cross sections according to the multipolarity of the transfer interaction. Particular attention is paid to characteristic structures in the angular distributions for the lower spin states and how they depend on the angular momentum carried by the transferred particles. 11 refs., 3 figs.

  12. Determination of the charge of relativistic heavy nuclei from emulsion tracks

    NASA Technical Reports Server (NTRS)

    Morgan, S. H., Jr.; Eby, P. B.

    1971-01-01

    The number of delta rays with energies between 50 and 150 keV that are produced by heavy nuclei in emulsions is calculated. The Z(2) dependence predicted by the first Born approximation is corrected by a direct calculation of the Mott exact phase-shift scattering cross section. Comparisons are made with corrections predicted by the second Born approximation. When the phase-shift results are applied to the problem of charge identification, corrections of up to 4 units of charge for 1.457-GeV/nucleon nuclei with charge Z = 75 are found.

  13. Symmetry-dictated trucation: Solutions of the spherical shell model for heavy nuclei

    SciTech Connect

    Guidry, M.W. |

    1992-12-31

    Principles of dynamical symmetry are used to simplify the spherical shell model. The resulting symmetry-dictated truncation leads to dynamical symmetry solutions that are often in quantitative agreement with a variety of observables. Numerical calculations, including terms that break the dynamical symmetries, are shown that correspond to shell model calculations for heavy deformed nuclei. The effective residual interaction is simple, well-behaved, and can be determined from basic observables. With this approach, we intend to apply the shell model in systematic fashion to all nuclei. The implications for nuclear structure far from stability and for nuclear masses and other quantities of interest in astrophysics are discussed.

  14. Competition between complete fusion and quasifission in reactions with heavy nuclei

    SciTech Connect

    Antonenko, N. V.; Scheid, W.; Adamian, G. G.; Volkov, V. V.

    1998-02-15

    A model based on the dinuclear system concept 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 Kramers-type expression. The calculated cross sections for the heaviest nuclei are in a good agreement with the experimental data. The experimentally observed rapid fall-off of the cross section of the cold fusion with increasing charge number Z of the compound nucleus is explained.

  15. Analytic optical potentials for nucleon-nucleus nucleus-nucleus collisions involving light and medium nuclei

    NASA Technical Reports Server (NTRS)

    Bidasaria, H. B.; Townsend, L. W.

    1982-01-01

    Utilizing an optical model potential approximation to the exact nucleus-nucleus multiple-scattering series, optical potentials for nucleon-nucleus and nucleus-nucleus collisions are analytically derived. These expressions are applicable to light and medium cosmic ray nuclei as their single-particle density distributions are analytically determined, without approximation, from their actual harmonic well charge density distributions. Pauli correlation effects are included through the use of a simple Gaussian function to replace the usual expression obtained in the infinite nuclear matter approximation.

  16. Effect of in-medium parameters of ρ meson in its photoproduction reactions on nuclei

    SciTech Connect

    Das, Swapan

    2015-03-15

    There exist model calculations showing the modification of the hadronic parameters of ρ meson in the nuclear environment. From these parameters, we extract the ρ-meson-nucleus optical potential and show the medium effect due to this potential on the ρ-meson mass distribution spectra in the photonuclear reactions. The calculated results reproduced reasonably the measured e{sup +}e{sup −} invariant mass, i.e., ρ-meson mass, distribution spectra in γ, ρ{sup 0} → e{sup +}e{sup −} reactions on nuclei.

  17. Neutron productions in the fragmentation of relativistic heavy nuclei and formation of a beam of high-energy neutrons

    NASA Astrophysics Data System (ADS)

    Yurevich, V. I.

    2016-03-01

    The production of quasimonoenergetic high-energy neutrons at zero angle (0°) in the spallation of relativistic heavy nuclei is discussed by considering the example of the interaction of lead nuclei with light target nuclei. It is shown that this process can be used to generate a beam of high-energy neutrons at existing heavy ion accelerators. At the same time, itmay lead to the appearance of a parasitic neutron beam because of the interaction of the heavy-ion beam used with beam line and experimental setup materials.

  18. Bridging the nuclear structure gap between stable and super heavy nuclei.

    SciTech Connect

    Seweryniak, D.; Khoo, T. L.; Ahmad, I.; Kondev, F. G.; Robinson, A.; Back, B. B.; Carpenter, M. P.; Davids, C. N.; Greene, J. P.; Gros, S.; Janssens, R. V. F.; Lauritsen, T.; Lister, C. J.; McCutchan, E. A.; Peterson, D.; Zhu, S. F.; Physics; Univ. of York; Univ. of Massachusetts at Lowell; Japan Atomic Energy Agency; Univ. of Jyvaskyla; CSNSM Orsay; Yale Univ.; Univ. of Liverpool; RIKEN; Univ. of Maryland; Univ. of Notre Dame

    2010-01-01

    Due to recent advances in detection techniques, excited states in several trans-fermium nuclei were studied in many laboratories worldwide, shedding light on the evolution of nuclear structure between stable nuclei and the predicted island of stability centered around spherical magic numbers. In particular, studies of K-isomers around the Z=100 and N=152 deformed shell closures extended information on the energies of Nilsson orbitals at the Fermi surface. Some of these orbitals originate from spherical states, which are relevant to the magic gaps in super-heavy nuclei. The single-particle energies can be used to test various theoretical predictions and aid in extrapolations towards heavier systems. So far, the Woods-Saxon potential reproduces the data best, while self-consistent approaches miss some of the observed features, indicating a need to modify the underlying effective nucleon-nucleon interactions.

  19. Production of heavy neutron-rich nuclei in transfer reactions within the dinuclear system model

    NASA Astrophysics Data System (ADS)

    Zhu, Long; Feng, Zhao-Qing; Zhang, Feng-Shou

    2015-08-01

    The dynamics of nucleon transfer processes in heavy-ion collisions is investigated within the dinuclear system model. The production cross sections of nuclei in the reactions 136Xe+208Pb and 238U+248Cm are calculated, and the calculations are in good agreement with the experimental data. The transfer cross sections for the 58Ni+208Pb reaction are calculated and compared with the experimental data. We predict the production cross sections of neutron-rich nuclei 165-168 Eu, 169-173 Tb, 173-178 Ho, and 181-185Yb based on the reaction 176Yb+238U. It can be seen that the production cross sections of the neutron-rich nuclei 165Eu, 169Tb, 173Ho, and 181Yb are 2.84 μb, 6.90 μb, 46.24 μb, and 53.61 μb, respectively, which could be synthesized in experiment.

  20. Influence of shell effects on the formation of light nuclei in collisions of heavy ions

    SciTech Connect

    Antonenko, N.V.; Dzholos, R.V. )

    1989-07-01

    Various approaches to calculation of the coefficients of the transport equation which describes the process of multinucleon transfers, are analyzed. It is shown that, without resorting to the averaging of matrix elements over many shell configurations, one can obtain expressions for transition probabilities that include the effects of nuclear shell structure. On this basis, the yield of light nuclei in reactions induced by heavy ions is studied in the framework of the degenerate-shell model. The calculations, which are carried out on the assumption that the wave functions of high-lying one-particle states of the system are not concentrated in one nucleus but are distributed over the two nuclei proportionally to their volumes, lead to an appreciable increase of the yield of light elements as compared to calculations in which one-particle states are assumed to belong to only one of the nuclei forming the double system.

  1. A mechanism for the abundance enhancements of heavy nuclei in solar flare particle events

    NASA Technical Reports Server (NTRS)

    Cartwright, B. G.; Mogro-Campero, A.

    1973-01-01

    A mechanism is proposed to account for the recently reported abundance enhancements of heavy nuclei in solar flares. The mechanism requires two acceleration stages for its operation: First, fully stripped ions are accelerated to suprathermal energies, and subsequently, a fraction of these ions are Fermi accelerated to higher energies. It is shown that because injection into Fermi acceleration is rigidity dependent and the ions may pick up electrons during transport to the Fermi acceleration region, an enhancement of the abundances of heavy nuclei can occur. The degree of the enhancement depends on a number of factors particular to each flare, so that the degree of enhancement may be variable from flare to flare, or may be a function of time within a given flare. In some flares, conditions may be such that no enhancement would be expected.

  2. Nonlinear ion-acoustic waves in a degenerate plasma with nuclei of heavy elements

    SciTech Connect

    Hossen, M. A. Mamun, A. A.

    2015-10-15

    The ion-acoustic (IA) solitary waves propagating in a fully relativistic degenerate dense plasma (containing relativistic degenerate electron and ion fluids, and immobile nuclei of heavy elements) have been theoretically investigated. The relativistic hydrodynamic model is used to derive the Korteweg-de Vries (K-dV) equation by the reductive perturbation method. The stationary solitary wave solution of this K-dV equation is obtained to characterize the basic features of the IA solitary structures that are found to exist in such a degenerate plasma. It is found that the effects of electron dynamics, relativistic degeneracy of the plasma fluids, stationary nuclei of heavy elements, etc., significantly modify the basic properties of the IA solitary structures. The implications of this results in astrophysical compact objects like white dwarfs are briefly discussed.

  3. Nonlinear ion-acoustic waves in a degenerate plasma with nuclei of heavy elements

    NASA Astrophysics Data System (ADS)

    Hossen, M. A.; Mamun, A. A.

    2015-10-01

    The ion-acoustic (IA) solitary waves propagating in a fully relativistic degenerate dense plasma (containing relativistic degenerate electron and ion fluids, and immobile nuclei of heavy elements) have been theoretically investigated. The relativistic hydrodynamic model is used to derive the Korteweg-de Vries (K-dV) equation by the reductive perturbation method. The stationary solitary wave solution of this K-dV equation is obtained to characterize the basic features of the IA solitary structures that are found to exist in such a degenerate plasma. It is found that the effects of electron dynamics, relativistic degeneracy of the plasma fluids, stationary nuclei of heavy elements, etc., significantly modify the basic properties of the IA solitary structures. The implications of this results in astrophysical compact objects like white dwarfs are briefly discussed.

  4. Studies of the ionization states of solar and galactic cosmic ray heavy nuclei

    NASA Technical Reports Server (NTRS)

    Biswas, S.

    1982-01-01

    Enhancement of abundances of heavy nuclei (e.g., Mg, Si, and Fe) at low energies relative to solar photospheric abundances and anomalously high abundances of iron relative to oxygen nuclei at low energies were recently discovered in solar energetic particles studied at low energy. These phenomena are not understood at present. The proposed experiment is designed to study the recently discovered anomalous component of low energy galactic cosmic ray ions of C, N, O, Ne, and Ca to Fe of energy 5- to 10-million electron volts per atomic mass unit in regard to their ionization states, composition, and intensity, and to study the ionization states of heavy elements from oxygen to iron in energetic solar particles emitted during flare events. The same detector system will serve for both studies, with the second objective being given priority if there are any solar particle events during the mission.

  5. Level densities of heavy nuclei in the shell model Monte Carlo approach

    NASA Astrophysics Data System (ADS)

    Alhassid, Y.; Bertsch, G. F.; Gilbreth, C. N.; Nakada, H.; Özen, C.

    2016-06-01

    Nuclear level densities are necessary input to the Hauser-Feshbach theory of compound nuclear reactions. However, the microscopic calculation of level densities in the presence of correlations is a challenging many-body problem. The configurationinteraction shell model provides a suitable framework for the inclusion of correlations and shell effects, but the large dimensionality of the many-particle model space has limited its application in heavy nuclei. The shell model Monte Carlo method enables calculations in spaces that are many orders of magnitude larger than spaces that can be treated by conventional diagonalization methods and has proven to be a powerful tool in the microscopic calculation of level densities. We discuss recent applications of the method in heavy nuclei.

  6. Composition and energy spectra of heavy nuclei of unknown origin detected on Skylab

    NASA Technical Reports Server (NTRS)

    Chan, J. H.; Price, P. B.

    1975-01-01

    At the orbit of Skylab, steeply falling energy spectra of nuclei with atomic numbers of at least 8 and energies between about 10 and 40 MeV/amu at intensities much higher than seen outside the magnetosphere were observed. The composition is consistent with that of the solar corona. It is suggested that heavy solar-wind ions enter the magnetosphere, are accelerated, and populate the inner radiation belt.

  7. {alpha}-decay calculations of heavy and superheavy nuclei using effective mean-field potentials

    SciTech Connect

    Pei, J. C.; Lin, Z. J.; Xu, F. R.; Zhao, E. G.

    2007-10-15

    Using an effective potential that is based on the Skyrme-Hartree-Fock mean-field model, systematic {alpha}-decay properties of even-even heavy and superheavy nuclei have been investigated. Calculations do not raise any adjustable parameter. The obtained {alpha}-decay half-lives agree reasonably well with experimental data. The characteristics of the effective potential and the deformation effect on the {alpha} decay are discussed.

  8. 75 FR 81952 - Greenhouse Gas Emissions Standards and Fuel Efficiency Standards for Medium- and Heavy-Duty...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-29

    ... text of the preamble. The proposed regulatory text for both NHTSA and EPA is not affected. In FR Doc... Vocational Diesel Engine Standards Over the Heavy-Duty FTP Cycle Medium Model year Standard Light heavy...) Regulatory subcategory Light heavy-duty Medium heavy-duty diesel engine diesel engine. Heavy...

  9. The In-Medium Similarity Renormalization Group: A novel ab initio method for nuclei

    NASA Astrophysics Data System (ADS)

    Hergert, H.; Bogner, S. K.; Morris, T. D.; Schwenk, A.; Tsukiyama, K.

    2016-03-01

    We present a comprehensive review of the In-Medium Similarity Renormalization Group (IM-SRG), a novel ab initio method for nuclei. The IM-SRG employs a continuous unitary transformation of the many-body Hamiltonian to decouple the ground state from all excitations, thereby solving the many-body problem. Starting from a pedagogical introduction of the underlying concepts, the IM-SRG flow equations are developed for systems with and without explicit spherical symmetry. We study different IM-SRG generators that achieve the desired decoupling, and how they affect the details of the IM-SRG flow. Based on calculations of closed-shell nuclei, we assess possible truncations for closing the system of flow equations in practical applications, as well as choices of the reference state. We discuss the issue of center-of-mass factorization and demonstrate that the IM-SRG ground-state wave function exhibits an approximate decoupling of intrinsic and center-of-mass degrees of freedom, similar to Coupled Cluster (CC) wave functions. To put the IM-SRG in context with other many-body methods, in particular many-body perturbation theory and non-perturbative approaches like CC, a detailed perturbative analysis of the IM-SRG flow equations is carried out. We conclude with a discussion of ongoing developments, including IM-SRG calculations with three-nucleon forces, the multi-reference IM-SRG for open-shell nuclei, first non-perturbative derivations of shell-model interactions, and the consistent evolution of operators in the IM-SRG. We dedicate this review to the memory of Gerry Brown, one of the pioneers of many-body calculations of nuclei.

  10. A high-resolution study of ultra-heavy cosmic-ray nuclei (A0178)

    NASA Technical Reports Server (NTRS)

    Osullivan, D.; Thompson, A.; Oceallaigh, C.; Domingo, V.; Wenzel, K. P.

    1984-01-01

    The main objective of the experiment is a detailed study of the charge spectra of ultraheavy cosmic-ray nuclei from zinc (Z = 30) to uranium (Z = 92) and beyond using solid-state track detectors. Special emphasis will be placed on the relative abundances in the region Z or - 65, which is thought to be dominated by r-process nucleosynthesis. Subsidiary objectives include the study of the cosmic-ray transiron spectrum a search for the postulated long-lived superheavy (SH) nuclei (Z or = 110), such as (110) SH294, in the contemporary cosmic radiation. The motivation behind the search for super-heavy nuclei is based on predicted half-lives that are short compared to the age of the Earth but long compared to the age of cosmic rays. The detection of such nuclei would have far-reaching consequences for nuclear structure theory. The sample of ultraheavy nuclei obtained in this experiment will provide unique opportunities for many tests concerning element nucleosynthesis, cosmic-ray acceleration, and cosmic-ray propagation.

  11. Production of heavy and superheavy neutron-rich nuclei in transfer reactions

    SciTech Connect

    Zagrebaev, V. I.; Greiner, Walter

    2011-04-15

    The problem of production and study of heavy neutron-rich nuclei has been intensively discussed during recent years. Many reasons arouse a great interest in this problem. The present limits of the upper part of the nuclear map are very close to the {beta} stability line while the unexplored area of heavy neutron-rich nuclides (also those located along the neutron closed shell N=126 to the right-hand side of the stability line) is extremely important for nuclear astrophysic investigations and, in particular, for the understanding of the r process of astrophysical nucleogenesis. For elements with Z>100 only neutron deficient isotopes (located to the left of the stability line) have been synthesized so far. The 'northeast' area of the nuclear map can be reached neither in fusion-fission reactions nor in fragmentation processes widely used nowadays for the production of new nuclei. Multinucleon transfer processes in near barrier collisions of heavy (and very heavy, U-like) ions seem to be the only reaction mechanism allowing us to produce and explore neutron-rich heavy nuclei including those located at the superheavy island of stability. In this paper several transfer reactions for different projectile-target combinations are studied in detail. Besides the predictions for the cross sections of such processes, we also analyze the angular and energy distributions of primary and survived reaction products in the laboratory frame. These results, as well as predicted excitation functions for the yields of neutron-rich superheavy isotopes, might be useful for the design of appropriate experimental equipment and for carrying out experiments of such kind.

  12. Nucleosynthesis of neutron-rich heavy nuclei during explosive helium burning in a 15 solar-mass supernova

    NASA Technical Reports Server (NTRS)

    Blake, J. B.; Woosley, S. E.; Weaver, T. A.; Schramm, D. N.

    1980-01-01

    The production of heavy nuclei during explosive helium burning has been calculated using the Weaver and Woosley self-consistent model of a complete 15 solar-mass star and the n-process code of Blake and Schramm. It was found that the resulting neutron-rich heavy nuclei are not produced in the relative abundances of solar-system r-process material (such as a Pt peak) nor are any actinides produced. Basically insufficient neutrons are available.

  13. Excitation energies of double isobar-analog states in heavy nuclei

    SciTech Connect

    Poplavskii, I. V.

    1988-12-01

    Several new relationships are established for isomultiplets on the basis of a theory in which the Coulomb coupling constant (CCC) is allowed to be complex. In particular, the following rule is formulated: the energies for fission or decay of members of an isomultiplet into a charged cluster and members of the corresponding daughter isomultiplet are equidistant. This relationship is well satisfied for isomultiplets with /ital A/less than or equal to60. By extrapolating the rule for fission and decay energies to the region of heavy nuclei, the excitation energies /ital E//sub /ital x// of double isobar-analog states (DIASs) are found for the nuclei /sup 197,199/Hg, /sup 205/Pb, /sup 205 - -209/Po, /sup 209/At, and /sup 238/Pu. A comparison of the computed energies /ital E//sub /ital x// with the experimentally measured values for /sup 208/Po attest to the reliability and good accuracy of the method proposed here when used to determine the excitation energies of DIASs in heavy nuclei.

  14. The project of the mass separator of atomic nuclei produced in heavy ion induced reactions

    NASA Astrophysics Data System (ADS)

    Oganessian, Yu. Ts.; Shchepunov, V. A.; Dmitriev, S. N.; Itkis, M. G.; Gulbekyan, G. G.; Khabarov, M. V.; Bekhterev, V. V.; Bogomolov, S. L.; Efremov, A. A.; Pashenko, S. V.; Stepantsov, S. V.; Yeremin, A. V.; Yavor, M. I.; Kalimov, A. G.

    2003-05-01

    A new separator and mass analyzer, named MASHA (mass analyzer of super heavy atoms), has been designed at the Flerov Laboratory JINR Dubna to separate and measure masses of nuclei and molecules with precision better than 10 -3. The set up can work in the wide mass range from A≈20 to A≈500, its mass acceptance is as large as ±2.8%. In particular, it allows unambiguous mass identification of super heavy nuclei with a resolution better than 1 amu at the level of 300 amu. Synthesized in nuclear reactions nuclides are emitted from an ECR ion source at energy E=40 kV and charge state Q=+1. Then they pass the following steps of separation and analysis: the first section of rough separation, the second section of separation and mass analysis and the final section of separation with a 90° electrostatic deflector. In the focal plane of the device, a focal plane detector determines positions (masses) of studied nuclei. Ion optics of the analyzer, optimized up to the second order, is considered. Description of its elements and subsystems is given.

  15. MCNP6 Simulation of Light and Medium Nuclei Fragmentation at Intermediate Energies

    SciTech Connect

    Mashnik, Stepan Georgievich; Kerby, Leslie Marie

    2015-05-22

    MCNP6, the latest and most advanced LANL Monte Carlo transport code, representing a merger of MCNP5 and MCNPX, is actually much more than the sum of those two computer codes; MCNP6 is available to the public via RSICC at Oak Ridge, TN, USA. In the present work, MCNP6 was validated and verified (V&V) against different experimental data on intermediate-energy fragmentation reactions, and results by several other codes, using mainly the latest modifications of the Cascade-Exciton Model (CEM) and of the Los Alamos version of the Quark-Gluon String Model (LAQGSM) event generators CEM03.03 and LAQGSM03.03. It was found that MCNP6 using CEM03.03 and LAQGSM03.03 describes well fragmentation reactions induced on light and medium target nuclei by protons and light nuclei of energies around 1 GeV/nucleon and below, and can serve as a reliable simulation tool for different applications, like cosmic-ray-induced single event upsets (SEU’s), radiation protection, and cancer therapy with proton and ion beams, to name just a few. Future improvements of the predicting capabilities of MCNP6 for such reactions are possible, and are discussed in this work.

  16. Formation of Heavy Compound Nuclei, Their Survival and Correlation with Longtime-Scale Fission

    SciTech Connect

    Karamian, S. A.; Yakushev, A.-B.

    2007-05-22

    Fusion of two massive nuclei with formation of super-heavy compound nucleus (CN) is driven by the potential energy gradient, as follows from the analysis of nuclear reaction cross-sections. The conservative energy of the system is deduced in simple approximation using regularized nuclear mass and interaction barrier values. Different reaction for the synthesis of Zc (110-118) nuclei are compared and the favourable conditions are found for fusion of the stable (W-Pt) isotopes with radioactive fission fragment projectiles, like 94Kr or 100Sr. Thus, the cold fusion method can be extended for a synthesis of elements with Z > 113. Survival of the evaporation residue is defined by the neutron-to-fission probability ratio and by the successful emission of gammas at final step of the reaction. Numerical estimates are presented. Fixation of evaporation residue products must correlate with longtime-scale fission and available experimental results are discussed.

  17. Ultrahigh energy cosmic rays as heavy nuclei from cluster accretion shocks

    NASA Astrophysics Data System (ADS)

    Inoue, Susumu; Sigl, Günter; Miniati, Francesco; et al.

    Large-scale accretion shocks around massive clusters of galaxies, generically expected in hierarchical scenarios of cosmological structure formation, are shown to be plausible sources of the observed ultrahigh energy cosmic rays (UHECRs) by accelerating a mixture of heavy nuclei including the iron group elements. Current observations can be explained if the source composition at injection for the heavier nuclei is somewhat enhanced from simple expectations for the accreting gas. The proposed picture should be clearly testable by current and upcoming facilities in the near future through characteristic features in the UHECR spectrum, composition and anisotropy, in particular the rapid increase of the average mass composition with energy from 1019 to 1020 eV. The associated X-ray and gamma-ray signatures are also briefly discussed.

  18. Frequency of light-flashes induced by Cerenkov radiation from heavy cosmic-ray nuclei

    NASA Technical Reports Server (NTRS)

    Madey, R.; Mcnulty, P. J.

    1972-01-01

    The expected frequency was calculated for light flashes induced in the dark-adapted eye by Cerenkov radiation from the flux of heavy nuclei that exists in space beyond the geomagnetic field. The expected frequency of light flashes depends on the threshold number of photons that must be absorbed in a rod cluster. The results of the calculation are presented as a curve of the mean frequency of light flashes versus the threshold number of absorbed photons. The results are not sensitive to variations in the path length from 5 to 15 grams per square centimeter of water-equivalent before the nucleus reaches the retina. Calculations were based on the fluxes and energy spectra of galactic cosmic ray nuclei of helium to iron, measured at a time of minimum solar modulation. The expected light flash frequencies induced by Cerenkov radiation are consistent with the frequencies reported by the astronauts on Apollo missions 11 through 14.

  19. Photo-disintegration of heavy nuclei at the core of Cen A

    SciTech Connect

    Kundu, Esha; Gupta, Nayantara E-mail: nayan@rri.res.in

    2014-04-01

    Fermi LAT has detected gamma ray emissions from the core of Cen A. More recently, a new component in the gamma ray spectrum from the core has been reported in the energy range of 4 GeV to tens of GeV. We show that the new component and the HESS detected spectrum of gamma rays from the core at higher energy have possibly a common origin in photo-disintegration of heavy nuclei. Assuming the cosmic rays are mostly Fe nuclei inside the core and their spectrum has a low energy cut-off at 52 TeV in the wind frame moving with a Doppler factor 0.25 with respect to the observer on earth, the cosmic ray luminosity required to explain the observed gamma ray flux above 1 GeV is found to be 1.5 × 10{sup 43} erg/sec.

  20. The Energetic Trans-Iron Composition Experiment (ENTICE) on the Heavy Nuclei Explorer (HNX) Mission

    NASA Technical Reports Server (NTRS)

    Hink, P. L.; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    The Energetic Trans-Iron Composition Experiment (ENTICE) experiment is one of two experiments which comprise the Heavy Nuclei Explorer (HNX) mission. The experimental goal of ENTICE is to measure with high precision the elemental abundances of all nuclei with 10LZL82. This will enable us to determine if the injection mechanism for the cosmic ray accelerator is controlled by FIP or Volatility and to study the mix of nucleosynthetic processes that contribute to the galactic cosmic ray source. The ENTICE experiment utilizes the dE/dx-C method of charge determination and consists of silicon dE/dx detectors, Cherenkov detectors with two different refractive indices, and a scintillating fiber hodoscope. The geometrical factor of the instrument is approximately 8m2sr. We will present a description of the instrument and its expected performance based on beam tests and a balloon flight of a prototype instrument.

  1. Energy Approach to Resonance states of Compound Superheavy Nucleus and EPPP in Heavy Nuclei Collisions

    SciTech Connect

    Glushkov, Alexander V.

    2005-10-26

    A consistent unified energy approach (operator perturbation theory) is used for numerical calculations of the electron-positron pair production cross-section in heavy nuclei collisions. Resonance phenomena in the nuclear subsystem lead to the structurization of the positron spectrum produced. The positron spectrum narrow peaks are treated as resonance states of the compound superheavy nucleus. Calculation results for the differential cross-sections of the U-U collision energies E1 (E1=162.0keV- third s-resonance; E1=247.6keV- the fourth s-resonance) are presented.

  2. Relativistic theory for the elementary process of bremsstrahlung induced by heavy spin-zero nuclei

    NASA Astrophysics Data System (ADS)

    Jakubassa-Amundsen, D. H.

    2016-05-01

    Doubly and triply differential cross sections for the bremsstrahlung emission by high-energy spin-polarized electrons in the field of heavy bare nuclei are calculated within a fully relativistic partial-wave approach at collision energies between 1 and 30 MeV. Investigating 208Pb as a test case, it is shown that if the photons are emitted at backward angles, nuclear size effects may play an important role even below 10 MeV. Comparison is made with experimental data on the circular polarization correlations between incoming electron and emitted photon at a collision energy of 3.5 MeV. It is demonstrated that, independent of energy, the plane-wave Born approximation severely underestimates the cross section for heavy targets. Moreover, it gives at most a qualitative prescription of the polarization correlations, except possibly in the forward hemisphere.

  3. Super-heavy nuclei with Z = 118 and their mass and charge spectrum of fission fragments

    NASA Astrophysics Data System (ADS)

    Maslyuk, V. T.; Smolyanyuk, A. V.

    2015-12-01

    The first results of the calculation of the mass and charge yields of fission fragments for over 60 isotopes which have Z = 118 are presented. The results were obtained from the condition of thermodynamic ordering of the ensemble of fission fragments. The role of neutrons shells with N = 82 or N = 126 and protons shells with Z = 50 in the realization of symmetric (or one-humped) and asymmetric (2- or 3-humped) shapes of the fission-fragment yields with the transition from neutron-proficient to neutron-deficient isotopes was investigated. The data of fragments yields had been analyzed under the conditions of a “cold” and “hot” fission. The calculations show the possibility to identify super-heavy nuclei with Z ≥ 118 produced synthetically by heavy-ion reaction on their mass/charge spectrum division.

  4. 77 FR 75257 - Proposed Collection of Information: Medium- and Heavy-Duty Truck Fleet Survey

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-19

    ... Truck Fleet Survey AGENCY: National Highway Traffic Safety Administration (NHTSA), Department of... medium- and heavy-duty truck fleet managers. DATES: Comments must be received within 60 days of...- and Heavy-Duty Truck Fleet Survey. Background: The Energy Independence and Security Act...

  5. Competition between {alpha} decay and spontaneous fission for heavy and superheavy nuclei

    SciTech Connect

    Xu Chang; Ren Zhongzhou; Guo Yanqing

    2008-10-15

    We systematically investigate the {alpha}-decay and spontaneous fission half-lives for heavy and superheavy nuclei with proton number Z{>=}90. The {alpha}-decay half-lives are obtained by the deformed version of the density-dependent cluster model (DDCM). In the DDCM, the microscopic potential between the {alpha} particle and the daughter nucleus is evaluated numerically from the double-folding model with the M3Y interaction. The influence of the core deformation on the double-folding potential is also properly taken into account by the multipole expansion method. The spontaneous fission half-lives of nuclei from {sup 232}Th to {sup 286}114 are calculated with the parabolic potential approximation by taking nuclear structure effects into account. The agreement between theoretical results and the newly observed data is satisfactory for both {alpha} emitters and spontaneous fission nuclei. The competition between {alpha} decay and spontaneous fission is analyzed in detail and the branching ratios of these two decay modes are predicted for the unknown cases.

  6. Charge-exchange resonances and restoration of the Wigner SU(4)-symmetry in heavy and superheavy nuclei

    NASA Astrophysics Data System (ADS)

    Lutostansky, Yu. S.; Tikhonov, V. N.

    2016-01-01

    Energies of the giant Gamow-Teller and analog resonances -EG and EA, respectively, - are calculated within the microscopic theory of finite Fermi system. The calculated energy difference ΔEG-A = EG-EA tends to zero with A in heavy nuclei indicating the restoration of Wigner SU(4)-symmetry. The calculated ΔEG-A values are in good agreement with the experimental data. The average deviation is 0.30MeV for the 33 considered nuclei where experimental data are available. The ΔEG-A values are investigated for very heavy and superheavy nuclei up to the mass number A = 290. Using the experimental data for the analog resonance energies, the isotopic dependence of the Coulomb energy differences for neighboring isobars are analyzed within the SU(4)-approach for more than 400 nuclei in the mass number range of A = 3-244. The Wigner SU(4)-symmetry restoration for heavy and superheavy nuclei is confirmed. It is shown that the restoration of SU(4)-symmetry does not contradict the possibility of the existence of the "island of stability" in the region of superheavy nuclei.

  7. Development of the Experimental Setup Dedicated for Alpha, Gamma and Electron Spectroscopy of Heavy Nuclei at FLNR JINR

    SciTech Connect

    Yeremin, A.; Malyshev, O.; Popeko, A.; Lopez-Martens, A.; Hauschild, K.; Dorvaux, O.; Saro, S.; Pantelika, D.

    2010-04-30

    Various types of reactions and identification techniques were applied in the investigation of formation cross sections and decay properties of transuranium elements. The fusion--evaporation reactions with heavy targets, recoil--separation techniques and identification of nuclei by the parent--daughter generic coincidences with the known daughter-nuclei after implantation into position--sensitive detectors were the most successful tools for production and identification of the heaviest elements known presently. This technique may be further improved and presently it may be very promising for the identification of new elements, search for new isotopes and measurement of new decay data for the known nuclei.At the Flerov Laboratory of Nuclear Reactions (JINR, Dubna), investigations of the complete fusion reactions leading to the synthesis of heavy and superheavy nuclei with the use of heavy ion beams from a powerful U400 cyclotron have been an important part of the experimental program. It is planned to upgrade U400 cyclotron of the FLNR, to deliver beams with higher intensities and smooth variation of energies.New experimental set up, the velocity filter, is now developing for synthesis and studies of the decay properties of heavy nuclei. At the focal plane of the separator GABRIELA set up (alpha,beta,gamma detectors array) will be installed.

  8. Excitation of Δ and N* resonances in isobaric charge-exchange reactions of heavy nuclei

    NASA Astrophysics Data System (ADS)

    Vidaña, I.; Benlliure, J.; Geissel, H.; Lenske, H.; Scheidenberger, C.; Vargas, J.

    2016-01-01

    We present a model for the study of the excitation of Δ(1232) and N*(1440) resonances in isobaric charge-exchange (AZ, A(Z ± 1)) reactions of heavy nuclei. Quasi-elastic and inelastic elementary processes contributing to the double differential cross sections of the reactions are described in terms of the exchange of virtual pions. The inelastic channel includes processes where the resonances are excited both in the target and in the projectile nucleus. We present results for reactions of 112Sn and 124Sn on different targets. Our results confirm that the position of the Δ peak is insensitive to targets with mass number A ≥ 12, and show that the origin of the Δ peak shift towards low excitation energies, with respect to its position in reactions with a proton target, can be easily explained in terms of the superposition of the different excitation mechanisms contributing to the reaction.

  9. Composition and energy spectra of heavy nuclei of unknown origin detected on Skylab

    NASA Technical Reports Server (NTRS)

    Chan, J. H.; Price, P. B.

    1975-01-01

    Lexan track detectors with large collecting power were exposed inside and outside Skylab during late 1973 and early 1974. Steeply falling energy spectra of nuclei with Z greater than or equal to 8 and energies between 10 and 40 MeV were observed at intensities much higher than those observed outside the magnetosphere. Four possible sources (solar flare particles; low-energy cosmic rays; the anomalous component of low-energy cosmic rays; particles trapped in the inner Van Allen belt) are examined using Skylab particle flux data outside the magnetosphere and other measurements. The composition is found to be most consistent with that of the solar corona. It is suggested that heavy solar wind ions enter the magnetosphere, are accelerated, and populate the inner radiation belt.

  10. Finite amplitude method applied to the giant dipole resonance in heavy rare-earth nuclei

    NASA Astrophysics Data System (ADS)

    Oishi, Tomohiro; Kortelainen, Markus; Hinohara, Nobuo

    2016-03-01

    Background: The quasiparticle random phase approximation (QRPA), within the framework of nuclear density functional theory (DFT), has been a standard tool to access the collective excitations of atomic nuclei. Recently, the finite amplitude method (FAM) was developed in order to perform the QRPA calculations efficiently without any truncation on the two-quasiparticle model space. Purpose: We discuss the nuclear giant dipole resonance (GDR) in heavy rare-earth isotopes, for which the conventional matrix diagonalization of the QRPA is numerically demanding. A role of the Thomas-Reiche-Kuhn (TRK) sum rule enhancement factor, connected to the isovector effective mass, is also investigated. Methods: The electric dipole photoabsorption cross section was calculated within a parallelized FAM-QRPA scheme. We employed the Skyrme energy density functional self-consistently in the DFT calculation for the ground states and FAM-QRPA calculation for the excitations. Results: The mean GDR frequency and width are mostly reproduced with the FAM-QRPA, when compared to experimental data, although some deficiency is observed with isotopes heavier than erbium. A role of the TRK enhancement factor in actual GDR strength is clearly shown: its increment leads to a shift of the GDR strength to higher-energy region, without a significant change in the transition amplitudes. Conclusions: The newly developed FAM-QRPA scheme shows remarkable efficiency, which enables one to perform systematic analysis of GDR for heavy rare-earth nuclei. The theoretical deficiency of the photoabsorption cross section could not be improved by only adjusting the TRK enhancement factor, suggesting the necessity of an approach beyond self-consistent QRPA and/or a more systematic optimization of the energy density functional (EDF) parameters.

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

    NASA Astrophysics Data System (ADS)

    Hofmann, S.; Heinz, S.; Mann, R.; Maurer, J.; Münzenberg, G.; Antalic, S.; Barth, W.; Burkhard, H. G.; Dahl, L.; Eberhardt, K.; Grzywacz, R.; Hamilton, J. H.; Henderson, R. A.; Kenneally, J. M.; Kindler, B.; Kojouharov, I.; Lang, R.; Lommel, B.; Miernik, K.; Miller, D.; Moody, K. J.; Morita, K.; Nishio, K.; Popeko, A. G.; Roberto, J. B.; Runke, J.; Rykaczewski, K. P.; Saro, S.; Scheidenberger, C.; Schött, H. J.; Shaughnessy, D. A.; Stoyer, M. A.; Thörle-Pospiech, P.; Tinschert, K.; Trautmann, N.; Uusitalo, J.; Yeremin, A. V.

    2016-06-01

    The reaction 54Cr + 248Cm 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.

  12. Research on coal cleaning by cyclone with CWS as heavy medium

    SciTech Connect

    Fu Xiaoheng; Wang Zuna

    1997-12-31

    A good rheologic Coal Water Slurry (CWS) was prepared by an advanced technique. The CWS is used as a heavy medium in cycloning for coal preparation. The concentration of the CWS is 55% by wt. and the density of the CWS is 1.286g/cm{sup 3}. The effect of the operation and equipment parameters of the CWS cyclone on preparation efficiency have been investigated in the laboratory. The results show that the separation process is similar to conventional heavy medium cyclone and gives good preparation efficiency, Ep being 0.04, for feed size between 1.8--5.0mm.

  13. Parity-projected shell model Monte Carlo level densities for medium-mass nuclei

    SciTech Connect

    Oezen, C.; Langanke, K.; Martinez-Pinedo, G.; Dean, D. J.

    2008-11-11

    We investigate the effects of single-particle structure and pairing on the equilibration of positive and negative-parity level densities for the even-even nuclei {sup 58,62,66}Fe and {sup 58}Ni and the odd-A nuclei {sup 59}Ni and {sup 65}Fe. Calculations are performed using the shell model Monte Carlo method in the complete fp-gds shell-model space using a pairing+quadrupole type residual interaction. We find for the even-even nuclei that the positive-parity states dominate at low excitation energies due to strong pairing correlations. At excitation energies at which pairs are broken, single-particle structure of these nuclei is seen to play the decisive role for the energy dependence of the ratio of negative-to-positive parity level densities. We also find that equilibration energies are noticeably lower for the odd-A nuclei {sup 59}Ni and {sup 65}Fe than for the neighboring even-even nuclei {sup 58}Ni and {sup 66}Fe.

  14. Idle emissions from medium heavy-duty diesel and gasoline trucks.

    PubMed

    Khan, A B M S; Clark, Nigel N; Gautam, Mridul; Wayne, W Scott; Thompson, Gregory J; Lyons, Donald W

    2009-03-01

    Idle emissions data from 19 medium heavy-duty diesel and gasoline trucks are presented in this paper. Emissions from these trucks were characterized using full-flow exhaust dilution as part of the Coordinating Research Council (CRC) Project E-55/59. Idle emissions data were not available from dedicated measurements, but were extracted from the continuous emissions data on the low-speed transient mode of the medium heavy-duty truck (MHDTLO) cycle. The four gasoline trucks produced very low oxides of nitrogen (NOx) and negligible particulate matter (PM) during idle. However, carbon monoxide (CO) and hydrocarbons (HCs) from these four trucks were approximately 285 and 153 g/hr on average, respectively. The gasoline trucks consumed substantially more fuel at an hourly rate (0.84 gal/hr) than their diesel counterparts (0.44 gal/hr) during idling. The diesel trucks, on the other hand, emitted higher NOx (79 g/hr) and comparatively higher PM (4.1 g/hr), on average, than the gasoline trucks (3.8 g/hr of NOx and 0.9 g/hr of PM, on average). Idle NOx emissions from diesel trucks were high for post-1992 model year engines, but no trends were observed for fuel consumption. Idle emissions and fuel consumption from the medium heavy-duty diesel trucks (MHDDTs) were marginally lower than those from the heavy heavy-duty diesel trucks (HHDDTs), previously reported in the literature. PMID:19320273

  15. ASE Program Certification Standards for Medium/Heavy Truck Technician Training Programs.

    ERIC Educational Resources Information Center

    National Automotive Technicians Education Foundation, Herndon, VA.

    This publication provides the evaluation policies, procedures, and standards to which a medium/heavy truck technician training program must adhere to be granted certification by the National Institute for Automotive Service Excellence. The policies section has three parts: the automobile areas that may be certified and minimum requirements for…

  16. Description of electromagnetic and favored α transitions in heavy odd-mass nuclei

    NASA Astrophysics Data System (ADS)

    Dumitrescu, A.; Delion, D. S.

    2016-02-01

    We describe electromagnetic and favored α transitions to rotational bands in odd-mass nuclei built upon a single particle state with angular momentum projection Ω ≠1/2 in the region 88 ≤Z ≤98 . We use the particle coupled to an even-even core approach described by the coherent state model and the coupled channels method to estimate partial α -decay widths. We reproduce the energy levels of the rotational band where favored α transitions occur for 26 nuclei and predict B (" close=")E 2 )">E 2 values for electromagnetic transitions to the band head using a deformation parameter and a Hamiltonian strength parameter for each nucleus, together with an effective collective charge depending linearly on the deformation parameter. Where experimental data are available, the contribution of the single particle effective charge to the total B value is calculated. The Hamiltonian describing the α -nucleus interaction contains two terms, a spherically symmetric potential given by the double-folding of the M3Y nucleon-nucleon interaction plus a repulsive core simulating the Pauli principle and a quadrupole-quadrupole (QQ) interaction. The α -decaying state is identified as a narrow outgoing resonance in this potential. The intensity of the transition to the first excited state is reproduced by the QQ coupling strength. It depends linearly both on the nuclear deformation and the square of the reduced width for the decay to the band head, respectively. Predicted intensities for transitions to higher excited states are in a reasonable agreement with experimental data. This formalism offers a unified description of energy levels, electromagnetic and favored α transitions for known heavy odd-mass α emitters.

  17. Isolation of cell nuclei in microchannels by short-term chemical treatment via two-step carrier medium exchange.

    PubMed

    Toyama, Kaori; Yamada, Masumi; Seki, Minoru

    2012-08-01

    Separation/purification of nuclei from cells is a critical process required for medical and biochemical research applications. Here, we report a flow-through microfluidic device for isolating cell nuclei by selectively digesting the cell membrane by using the concept of hydrodynamic filtration (HDF). When a cell suspension is continuously introduced into a microchannel (main channel) possessing multiple side channels, cells flow through the main channel, whereas the carrier medium of the cells is drained through the side channels. Introductions of a cell treatment solution containing a surfactant and a washing buffer enable the two-step exchange of the carrier-medium and the cell treatment by the surfactant for a short span of time. The precise control of the treatment time by changing the flow rate and/or the size of the microchannel enables the selective digestion of cell membranes, resulting in the isolation of cell nuclei after separation from membrane debris and cytoplasmic components according to size. We examined several surfactant molecules and demonstrated that Triton X-100 exhibited high efficiency regarding nucleus isolation for both adherent (HeLa) and nonadherent (JM) cells, with a recovery ratio of ~80 %. In addition, the isolation efficiency was evaluated by western blotting. The presented flow-through microfluidic cell-nucleus separator may be a useful tool for general biological applications, because of its simplicity in operation, high reproducibility, and accuracy. PMID:22544390

  18. Fragmentation of spherical radioactive heavy nuclei as a novel probe of transient effects in fission

    SciTech Connect

    Schmitt, C.; Schmidt, K.-H.; Kelic, A.; Heinz, A.; Jurado, B.

    2010-06-15

    Peripheral collisions with radioactive heavy-ion beams at relativistic energies are discussed as an innovative approach for probing the transient regime experienced by fissile systems evolving toward quasiequilibrium and thereby studying the viscous nature of nuclear matter. A dedicated experiment using the advanced technical installations of GSI, Darmstadt, made it possible to realize ideal conditions for the investigation of relaxation effects in a metastable well. Combined with a highly sensitive experimental signature, it provides a measure of the transient effects with respect to the flux over the fission barrier. Within a two-step reaction process, 45 proton-rich unstable spherical isotopes between At and Th produced by projectile-fragmentation of a stable {sup 238}U beam have been used as secondary projectiles which impinge on lead target nuclei. The fragmentation of the radioactive projectiles results in nearly spherical compound nuclei that span a wide range in excitation energy and fissility. The decay of these excited systems by fission is studied with a dedicated setup which, together with the inverse kinematics of the reaction, permits the detection of both fission products in coincidence and the determination of their atomic numbers with high resolution. The information on the nuclear charges of the two fragments is used to sort the data according to the initial excitation energy and fissility of the compound nucleus. The width of the fission-fragment nuclear charge distribution is shown to be specifically sensitive to presaddle transient effects and is used to establish a clock for the passage of the saddle point. The comparison of the experimental results with model calculations points to a fission delay tau{sub trans} of (3.3+-0.7)x10{sup -21} s for initially spherical compound nuclei, independent of excitation energy and fissility. This value suggests a nuclear dissipation strength beta at small deformation of (4.5+-0.5)x10{sup 21} s{sup -1}. The

  19. Density functional theory computation of Nuclear Magnetic Resonance parameters in light and heavy nuclei

    NASA Astrophysics Data System (ADS)

    Sutter, Kiplangat

    This thesis illustrates the utilization of Density functional theory (DFT) in calculations of gas and solution phase Nuclear Magnetic Resonance (NMR) properties of light and heavy nuclei. Computing NMR properties is still a challenge and there are many unknown factors that are still being explored. For instance, influence of hydrogen-bonding; thermal motion; vibration; rotation and solvent effects. In one of the theoretical studies of 195Pt NMR chemical shift in cisplatin and its derivatives illustrated in Chapter 2 and 3 of this thesis. The importance of representing explicit solvent molecules explicitly around the Pt center in cisplatin complexes was outlined. In the same complexes, solvent effect contributed about half of the J(Pt-N) coupling constant. Indicating the significance of considering the surrounding solvent molecules in elucidating the NMR measurements of cisplatin binding to DNA. In chapter 4, we explore the Spin-Orbit (SO) effects on the 29Si and 13C chemical shifts induced by surrounding metal and ligands. The unusual Ni, Pd, Pt trends in SO effects to the 29Si in metallasilatrane complexes X-Si-(mu-mt)4-M-Y was interpreted based on electronic and relativistic effects rather than by structural differences between the complexes. In addition, we develop a non-linear model for predicting NMR SO effects in a series of organics bonded to heavy nuclei halides. In chapter 5, we extend the idea of "Chemist's orbitals" LMO analysis to the quantum chemical proton NMR computation of systems with internal resonance-assisted hydrogen bonds. Consequently, we explicitly link the relationship between the NMR parameters related to H-bonded systems and intuitive picture of a chemical bond from quantum calculations. The analysis shows how NMR signatures characteristic of H-bond can be explained by local bonding and electron delocalization concepts. One shortcoming of some of the anti-cancer agents like cisplatin is that they are toxic and researchers are looking for

  20. Strangeness production in heavy ion collisions -Constraining the KN - potential in medium

    NASA Astrophysics Data System (ADS)

    Leifels, Yvonne; FOPI Collaboration

    2013-03-01

    We review the strangeness production in heavy ion collisions at energies around the NN production threshold and discuss recent measurements of the FOPI collaboration on charged kaon flow over a wide impact parameter range. The data are compared to comprehensive state-of-the-art transport models. The dense nuclear matter environment produced in those collisions may provide unique opportunities to form strange few body systems. The FOPI detector is especially suited to reconstruct such states by their charged particle decays. Apart from strongly decaying states special emphasis will be put on the search for long living weakly decaying states, i.e. Hyper-Nuclei. Light hyper nuclei are reconstructed by their two body decay channels and the production of Hyper-Tritons is studied with respect to Λ and t(3He).

  1. Pygmy dipole resonance as a constraint on the neutron skin of heavy nuclei

    SciTech Connect

    Piekarewicz, J.

    2006-04-15

    The isotopic dependence of the isovector Pygmy dipole response in tin is studied within the framework of the relativistic random-phase approximation. Regarded as an oscillation of the neutron skin against the isospin-symmetric core, the pygmy dipole resonance may place important constraints on the neutron skin of heavy nuclei and, as a result, on the equation of state of neutron-rich matter. The present study centers around two questions. First, is there a strong correlation between the development of a neutron skin and the emergence of low-energy isovector dipole strength? Second, could one use the recently measured Pygmy dipole resonance in {sup 130}Sn and {sup 132}Sn to discriminate among theoretical models? For the first question we found that although a strong correlation between the neutron skin and the Pygmy dipole resonance exists, a mild anticorrelation develops beyond {sup 120}Sn. The answer to the second question suggests that models with overly large neutron skins--and thus stiff symmetry energies--are in conflict with experiment.

  2. Density slope of the nuclear symmetry energy from the neutron skin thickness of heavy nuclei

    SciTech Connect

    Chen Liewen; Ko Che Ming; Xu Jun; Li Baoan

    2010-08-15

    Expressing explicitly the parameters of the standard Skyrme interaction in terms of the macroscopic properties of asymmetric nuclear matter, we show in the Skyrme-Hartree-Fock approach that unambiguous correlations exist between observables of finite nuclei and nuclear matter properties. We find that existing data on neutron skin thickness {Delta}r{sub np} of Sn isotopes give an important constraint on the symmetry energy E{sub sym}({rho}{sub 0}) and its density slope L at saturation density {rho}{sub 0}. Combining these constraints with those from recent analyses of isospin diffusion and the double neutron/proton ratio in heavy-ion collisions at intermediate energies leads to a more stringent limit on L approximately independent of E{sub sym}({rho}{sub 0}). The implication of these new constraints on the {Delta}r{sub np} of {sup 208}Pb as well as the core-crust transition density and pressure in neutron stars is discussed.

  3. Use of relativistic rise in ionization chambers for measurement of high energy heavy nuclei

    NASA Technical Reports Server (NTRS)

    Barthelmy, S. D.; Israel, M. H.; Klarmann, J.; Vogel, J. S.

    1983-01-01

    A balloon-borne instrument has been constructed to measure the energy spectra of cosmic-ray heavy nuclei in the range of about 0.3 to about 100 GeV/amu. It makes use of the relativistic rise portion of the Bethe-Bloch curve in ionization chambers for energy determination in the 10- to 100-GeV/amu interval. The instrument consists of six layers of dual-gap ionization chambers for energy determination above 10 GeV/amu. Charge is determined with a NE114 scintillator and a Pilot 425 plastic Cerenkov counter. A CO2 gas Cerenkov detector (1 atm; threshold of 30 GeV/amu) calibrates the ion chambers in the relativistic rise region. The main emphasis of the instrument is the determination of the change of the ratio of Iron (26) to the Iron secondaries (21-25) in the energy range of 10 to 100 GeV/amu. Preliminary data from a balloon flight in the fall of 1982 from Palestine, TX is presented.

  4. Heavy quark scattering and quenching in a QCD medium at finite temperature and chemical potential

    NASA Astrophysics Data System (ADS)

    Berrehrah, H.; Bratkovskaya, E.; Cassing, W.; Gossiaux, P. B.; Aichelin, J.

    2015-05-01

    The heavy quark collisional scattering on partons of the quark gluon plasma (QGP) is studied in a quantum chromodynamics medium at finite temperature and chemical potential. We evaluate the effects of finite parton masses and widths, finite temperature T , and quark chemical potential μq on the different elastic cross sections for dynamical quasiparticles (on- and off-shell particles in the QGP medium as described by the dynamical quasiparticle model "DQPM") using the leading order Born diagrams. Our results show clearly the decrease of the q Q and g Q total elastic cross sections when the temperature and the quark chemical potential increase. These effects are amplified for finite μq at temperatures lower than the corresponding critical temperature Tc(μq) . Using these cross sections we, furthermore, estimate the energy loss and longitudinal and transverse momentum transfers of a heavy quark propagating in a finite temperature and chemical potential medium. Accordingly, we have shown that the transport properties of heavy quarks are sensitive to the temperature and chemical potential variations. Our results provide some basic ingredients for the study of charm physics in heavy-ion collisions at Beam Energy Scan at RHIC and CBM experiment at FAIR.

  5. Increased delivery of condensation nuclei during the Late Heavy Bombardment to the terrestrial and martian atmospheres

    NASA Astrophysics Data System (ADS)

    Losiak, Anna

    2014-05-01

    During the period of the Late Heavy Bombardment (LHB), between 4.1 and 3.8 Ga, the impact rate within the entire Solar System was up to a few thousand times higher than the current value (Ryder 2002, Bottke et al. 2012, Fassett and Minton 2013). Multiple basin-forming events on inner planets that occurred during this time had a strong but short-lasting (up to few thousands of years) effect on atmospheres of Earth and Mars (Sleep et al. 1989, Segura et al. 2002, 2012). However, the role of the continuous flux of smaller impactors has not been assessed so far. We calculated the amount of meteoric material in the 10^-3 kg to 106 kg size range delivered to Earth and Mars during the LHB based on the impact flux at the top of the Earth's atmosphere based on results from Bland and Artemieva (2006). Those values were recalculated for Mars based on Ivanov and Hartmann (2009) and then recalculated to the LHB peak based on estimates from Ryder (2002), Bottke et al. (2012), Fassett and Minton (2013). During the LHB, the amount of meteoritic material within this size range delivered to Earth was up to ~1.7*10^10 kg/year and 1.4*10^10 kg/year for Mars. The impactors that ablate and are disrupted during atmospheric entry can serve as cloud condensation nuclei (Rosen 1968, Hunten et al. 1980, Ogurtsov and Raspopov 2011). The amount of material delivered during LHB to the upper stratosphere and lower mezosphere (Hunten et al. 1980, Bland and Artemieva 2006) is comparable to the current terrestrial annual emission of mineral cloud condensation nuclei of 0.5-8*10^12 kg/year (Tegen 2003). On Mars, the availability of condensation nuclei is one of the main factors guiding water-ice cloud formation (Montmessin et al. 2004), which is in turn one of the main climatic factors influencing the hydrological cycle (Michaels et al. 2006) and radiative balance of the planet (Haberle et al. 1999, Wordsworth et al. 2013, Urata and Toon 2013). Increased delivery of condensation nuclei during the

  6. Setup with Laser Ionization in Gas Cell for Production and Study of Neutron-Rich Heavy Nuclei

    NASA Astrophysics Data System (ADS)

    Zagrebaev, V. I.; Zemlyanoy, S. G.; Kozulin, E. M.; Kudryavtsev, Yu.; Fedosseev, V.; Bark, R.; Janas, Z.; Othman, H. A.

    2015-11-01

    The present limits of the upper part of the nuclear map are very close to stability while the unexplored area of heavy neutron-rich nuclides along the neutron closed shell N=126 is extremely important for nuclear astrophysics investigations and, in particular, for the understanding of the r-process of astrophysical nucleosynthesis. This area of the nuclear map can be reached neither in fusion-fission reactions nor in fragmentation processes widely used nowadays for the production of exotic nuclei. A new way was recently proposed for the production of these nuclei via low-energy multi-nucleon transfer reactions. The estimated yields of neutron-rich nuclei are found to be significantly high in such reactions and several tens of new nuclides can be produced, for example, in the near-barrier collision of 136Xe with 208Pb. A new setup is proposed to produce and study heavy neutron-rich nuclei located along the neutron closed shell N=126.

  7. Phase and structural transformations in metallic iron under the action of heavy ions and recoil nuclei.

    PubMed

    Alekseev, I; Novikov, D

    2014-02-01

    By the use of various modes of Mössbauer spectroscopy after effects of irradiation of metal iron with (12)C(4+) and (14)N(5+) ions of medium energies, and alpha-particles and the (208)Tl, (208,212)Pb, and (216)Po recoil from a (228)Th-source have been studied. The experimental data obtained in the study enabled various types of external and internal radiation to be compared in regard to the damage they cause, as well as to their effect on the structure-, phase composition- and corrosion resistance properties of metallic iron. Irradiation with (12)C(4+) and (14)N(5+) ions is accompanied by both structural disordering of the α-Fe lattice, and the appearance of γ-phase in the bulk metal. This is indicated by a single line which is 2 to 3-fold broadened (as compared to the lines of the magnetic sextet). This is a result of a strong local heating of the lattice in the thermal spike area with a subsequent instant cooling-down and recrystallization of this "molted" area. Irradiation of iron foils with (12)C(4+)- and (14)N(5+) ions and with recoil nuclei does provoke corrosion processes (the formation of γ-FeOOH) and is accompanied by an intensive oxidation of the metal. PMID:24378918

  8. Heavy quarks and nuclei, or the charm & beauty of nuclear physics

    SciTech Connect

    Kharzeev, D.

    1997-09-22

    This report contains viewgraphs on the following: why heavy quarks? Heavy quarkonium in QCD vacuum and in matter; Phenomenology of quarkonium production; Induced decay of QCD vacuum in heavy ion collisions? Implications for quarkonium production; and Outlook.

  9. Clean Cities Guide to Alternative Fuel and Advanced Medium- and Heavy-Duty Vehicles (Book)

    SciTech Connect

    Not Available

    2013-08-01

    Today's fleets are increasingly interested in medium-duty and heavy-duty vehicles that use alternative fuels or advanced technologies that can help reduce operating costs, meet emissions requirements, improve fleet sustainability, and support U.S. energy independence. Vehicle and engine manufacturers are responding to this interest with a wide range of options across a steadily growing number of vehicle applications. This guide provides an overview of alternative fuel power systems?including engines, microturbines, electric motors, and fuel cells?and hybrid propulsion systems. The guide also offers a list of individual medium- and heavy-duty vehicle models listed by application, along with associated manufacturer contact information, fuel type(s), power source(s), and related information.

  10. Clean Cities Guide to Alternative Fuel and Advanced Medium- and Heavy-Duty Vehicles

    SciTech Connect

    2013-08-01

    Today's fleets are increasingly interested in medium-duty and heavy-duty vehicles that use alternative fuels or advanced technologies that can help reduce operating costs, meet emissions requirements, improve fleet sustainability, and support U.S. energy independence. Vehicle and engine manufacturers are responding to this interest with a wide range of options across a steadily growing number of vehicle applications. This guide provides an overview of alternative fuel power systems--including engines, microturbines, electric motors, and fuel cells--and hybrid propulsion systems. The guide also offers a list of individual medium- and heavy-duty vehicle models listed by application, along with associated manufacturer contact information, fuel type(s), power source(s), and related information.

  11. Impact of momentum space anisotropy on heavy quark dynamics in a QGP medium

    NASA Astrophysics Data System (ADS)

    Chandra, Vinod; Das, Santosh K.

    2016-05-01

    Momentum space anisotropy present in the quark and gluon distribution functions in relativistic heavy ion collisions induces Chromo-Weibel instability in the hot QCD medium created therein. The impact of the Chromo-Weibel instability on the dynamics of a heavy quark (HQ) traversing in the QGP medium is investigated within the framework of kinetic theory by studying the momentum and temperature behavior of HQ drag and diffusion coefficients. The physics of anisotropy is captured in an effective Vlasov term in the transport equation. The effects of the instability are handled by making a relation with the phenomenologically known jet-quenching parameter in RHIC and LHC. Interestingly, the presence of instability significantly affects the temperature and momentum dependences of the HQ drag and diffusion coefficients. These results may have appreciable impact on the experimental observables such as the nuclear suppression factor, RA A(pT) , and the elliptic flow, v2(pT), of heavy mesons in heavy ion collisions at RHIC and LHC energies which is a matter of future investigation.

  12. Dynamical evolution, hadronization and angular de-correlation of heavy flavor in a hot and dense QCD medium

    NASA Astrophysics Data System (ADS)

    Cao, Shanshan; Qin, Guang-You; Bass, Steffen A.

    2014-12-01

    We study heavy flavor evolution and hadronization in relativistic heavy-ion collisions. The in-medium evolution of heavy quarks is described using our modified Langevin framework that incorporates both collisional and radiative energy loss mechanisms. The subsequent hadronization process for heavy quarks is calculated with a fragmentation plus recombination model. We find significant contribution from gluon radiation to heavy quark energy loss at high pT; the recombination mechanism can greatly enhance the D meson production at medium pT. Our calculation provides a good description of the D meson nuclear modification at the LHC. In addition, we explore the angular correlation functions of heavy flavor pairs which may provide us a potential candidate for distinguishing different energy loss mechanisms of heavy quarks inside the QGP.

  13. In-medium effects via nuclear stopping in asymmetric colliding nuclei

    NASA Astrophysics Data System (ADS)

    Kaur, Mandeep

    2016-05-01

    The nuclear stopping is studied using isospin-dependent quantum molecular dynamics (IQMD) model in asymmetric colliding nuclei by varying mass asymmetry. The calculations have been done at incident energies varying between 50 and 400 MeV/nucleon for different impact parameters. We investigate the relative role of constant scaled and density-dependent scaled cross-sections. Our study reveals that nuclear stopping depends on the mass asymmetry, incident energy and impact parameter, however, it is independent of the way of scaling the cross-section.

  14. Self-consistent description of coexistence phenomena in medium mass nuclei

    SciTech Connect

    Petrovici, A.; Schmid, K. W.; Faessler, Amand; Andrei, O.

    2010-11-24

    Shape coexistence and mixing, isospin mixing, the competition between neutron-proton and like-nucleon pairing correlations have been identified as the main characteristic features of nuclei near the N = Z line in the A{approx_equal}70 mass region. The self-consistent treatment of exotic phenomena dominated by their interplay represents a challenge for the nuclear many-body models. The realistic description of tiny effects in this mass region aiming to test the fundamental interactions and symmetries as well as the required theoretical predictions concerning the nuclear properties relevant for astrophysical scenarios are still open problems of the low-energy nuclear physics today.

  15. Experimental investigation of the physical properties of medium and heavy oils, their vaporization and use in explosion engines. Part III

    NASA Technical Reports Server (NTRS)

    Heinlein, Fritz

    1926-01-01

    The test equipment for studying the vaporization of heavy and medium oils is described as well as some of the experimental properties explored such as vaporization speed and diffusion coefficient. The experiemtal arrangement is also discussed.

  16. Comparative study of depth dose distributions for beams of light and heavy nuclei in tissue-like media

    NASA Astrophysics Data System (ADS)

    Pshenichnov, Igor; Mishustin, Igor; Greiner, Walter

    2008-04-01

    We study the energy deposition by beams of light and heavy nuclei in tissue-like media for their possible application in charged-particle cancer therapy. The depth-dose distributions for protons, 3He, 12C, 20Ne and 58Ni nuclei are calculated within a Monte Carlo model based on the GEANT4 toolkit. These distributions are compared with each other and with available experimental data. It is demonstrated that nuclear fragmentation reactions essentially reduce the peak-to-plateau ratio of the dose profiles for deeply penetrating energetic ions heavier than 3He. On the other hand, the shapes of depth-dose profiles for all projectiles up to 58Ni were found similar at low penetration depths.

  17. Nuclear shape transitions in neutron-rich medium-mass nuclei

    SciTech Connect

    Sarriguren, P.; Rodriguez-Guzman, R.; Robledo, L. M.

    2012-10-20

    We study the isotopic evolution of the ground-state nuclear shapes in neutron-rich Kr, Rb, Sr, Y, Zr, Nb, and Mo isotopic chains. Both even-even and odd-A nuclei are included in the analysis. For the latter we also study the systematics of their one-quasiparticle low-lying configurations. The theoretical approach is based on a selfconsistent Hartree-Fock-Bogoliubov formalism with finite range Gogny energy density functionals. Neutron separation energies, charge radii, and the spin-parity of the ground states are calculated and compared with available data. Shape-transition signatures are identified around N= 60 isotones as discontinuities in both charge radii isotopic shifts and spin-parities of the ground states. The nuclear deformation including triaxiality is shown to play a relevant role in the understanding of the bulk and spectroscopic features of the ground and low-lying one-quasiparticle states.

  18. Interplay between proton-neutron pairing and deformation in self-conjugated medium mass nuclei

    NASA Astrophysics Data System (ADS)

    Gambacurta, Danilo; Lacroix, Denis

    2016-05-01

    We employ a model combining self-consistent mean-field and shell model techniques to study the competition between particle-like and proton-neutron pairing correlations in fp-shell even-even self-conjugate nuclei. Deformation effects are realistically and microscopically described. The resulting approach can give a precise description of pairing correlations and eventually treat the coexistence of different condensate formed of pairs with different total spin/ isospin. The standard BCS calculations are systematically compared with approaches including correlation effects beyond the independent quasi-particle picture. The competition between proton-neutron correlations in the isoscalar and isovector channels is also analyzed, as well as their dependence on the deformation properties.

  19. Shell model estimate of electric dipole moment in medium and heavy nuclei

    SciTech Connect

    Yoshinaga, Naotaka; Higashiyama, Koji

    2011-05-06

    The nuclear electric dipole moment (EDM) and the nuclear Schiff moment for the lowest 1/2{sup +} state of {sup 129}Xe are investigated in terms of the nuclear shell model. We estimate the upper limit for the EDM of neutral {sup 129}Xe atom using the Schiff moment. We also estimate the upper limit of the nuclear EDM, which may be directly measured through ionic atoms.

  20. First measurement of the spectral function at high energy and momentum in medium-heavy nuclei

    SciTech Connect

    Daniela Rohe; E97-006 collaboration

    2005-09-26

    The experiment E97-006 was performed at Jefferson Lab to measure the momentum and energy distribution of protons in the nucleus far from the region of the (approximate) validity of the mean field description, i.e. at high momentum and energies. The occurrence of this strength is long known from occupation numbers less than one. In the experiment reported here this strength was directly measured for the first time. The results are compared to modern many-body theories. Further the transparency factor of C12 was determined in the Q{sup 2}-region of 0.6 to 1.8 (GeV/c){sup 2}.

  1. Light (anti-)nuclei production and flow in relativistic heavy-ion collisions

    NASA Astrophysics Data System (ADS)

    Zhu, Lilin; Ko, Che Ming; Yin, Xuejiao

    2015-12-01

    Using the coalescence model based on the phase-space distributions of protons, neutrons, Λ s , and their antiparticles from a multiphase transport (AMPT) model, we study the production of light nuclei (H, H, He, H) and their antinuclei in Pb+Pb collisions at √{sN N}=2.76 TeV. The resulting transverse momentum spectra, elliptic flows, and coalescence parameters for these nuclei are presented and compared with available experimental data. We also show the constituent number scaled elliptic flows of these nuclei and discuss its implications.

  2. Comparison of DD, DT and Cf-252 neutron excitation of light and medium mass nuclei for field PGNAA applications

    NASA Astrophysics Data System (ADS)

    Seabury, E. H.; Blackburn, B. W.; Chichester, D. L.; Wharton, C. J.; Caffrey, A. J.

    2007-08-01

    Prompt Gamma Ray Neutron activation analysis can offer significant cost and safety advantages in the identification of explosives and toxic chemicals. As an example, the US military examined over a thousand suspect chemical munitions with Idaho National Laboratory's PINS Chemical Assay System last year. PGNAA requires, of course, a neutron source to excite the atomic nuclei of the item under test via neutron capture and inelastic neutron scattering reactions and the choice of neutron source can drastically affect PGNAA system performance. We have carried out Monte Carlo and laboratory experiments comparing DD, DT and Cf-252 neutrons incident on light and medium mass chemical elements, toward optimizing the design of future neutron-generator-based PGNAA systems for field use. We report the excitation of (n, γ) and (n, n‧) gamma rays from these elements by each type of neutron source.

  3. Experimental investigation of the physical properties of medium and heavy oils, their vaporization and use in explosion engines. Part IV

    NASA Technical Reports Server (NTRS)

    Heinlein, Fritz

    1926-01-01

    This report presents a theoretical treatment of the vaporization process of medium and heavy oils. The results of this investigation, which were mostly obtained from the lighter components of the heavy fuels, require a 10- or 16-fold vaporization in comparison with gasoline. We must attain a still finer degree of atomization, in order to include the heavier components.

  4. Isotopic dependence of the cross section for the induced fission of heavy nuclei

    SciTech Connect

    Bolgova, O. N.; Adamian, G. G.; Antonenko, N. V.; Zubov, A. S.; Ivanova, S. P.; Scheid, W.

    2009-06-15

    The cross sections for the induced fission of {sup 211-223}Ra, {sup 203-211}Rn, and {sup 221-231}Th nuclei undergoing peripheral collisions with {sup 208}Pb nuclei are calculated on the basis of the statistical model. The role of the N = 126 neutron shell is studied. The level density in excited nuclei is determined within the Fermi gas model and a model that takes into account the collective enhancement of the level density. The inclusion of a particle-hole excitation in addition to a collective Coulomb excitation makes it possible to obtain a satisfactory description of experimental cross sections for the fission of radium isotopes. The calculated ratios of the cross sections for the induced fission of {sup 236}U ({sup 237}U) and {sup 238}U ({sup 239}U) nuclei agree with experimental data.

  5. Role of compound nuclei in intermediate-energy heavy-ion reactions

    SciTech Connect

    Moretto, L.G.; Wozniak, G.J.

    1988-05-01

    Hot compound nuclei are frequently produced in intermediate-energy reactions through a variety of processes. Their decay is shown to be an important and at times dominant source of complex fragments, high energy-gamma rays, and even pions.

  6. Enrichment of heavy nuclei in He-3-rich flares. [Imp-7 observed solar events

    NASA Technical Reports Server (NTRS)

    Hurford, G. J.; Mewaldt, R. A.; Stone, E. C.; Vogt, R. E.

    1975-01-01

    IMP-7 observations of five solar-flare particle events characterized by He-3 enrichment are reported which show that such events are also enriched in nuclei with charges (Z) of at least 6. The ratio of these nuclei to H-1 at approximately 3 MeV/nucleon was found to be enriched by about 10 to 100 times, while the ratio with respect to He-4 was enriched by about 3 to 30 times. It is suggested that the simultaneous enhancement of He-3 and the heavier nuclei as well as the absence of H-2 and H-3 during the observed events may be partly due to a preferential acceleration process which depends on the ratio of the square of the charge to the atomic weight of the nuclei.

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

    SciTech Connect

    Robledo, L. M.

    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.

  8. Properties and synthesis of heavy nuclei and properties of neutron star matter

    NASA Technical Reports Server (NTRS)

    Buchler, J. R.

    1974-01-01

    The nuclear Thomas-Fermi model which is based on nuclear matter calculations has been successfully applied to the study of the bulk properties of nuclei. It is ideally suited for extrapolation into the region of very neutron-rich and of superheavy nuclei. It is therefore a valuable approach for r-process calculations as well as for the study of neutron star matter at subnuclear densities.

  9. Inefficient Driving of Bulk Turbulence By Active Galactic Nuclei in a Hydrodynamic Model of the Intracluster Medium

    NASA Astrophysics Data System (ADS)

    Reynolds, Christopher S.; Balbus, Steven A.; Schekochihin, Alexander A.

    2015-12-01

    Central jetted active galactic nuclei (AGNs) appear to heat the core regions of the intracluster medium (ICM) in cooling-core galaxy clusters and groups, thereby preventing a cooling catastrophe. However, the physical mechanism(s) by which the directed flow of kinetic energy is thermalized throughout the ICM core remains unclear. We examine one widely discussed mechanism whereby the AGN induces subsonic turbulence in the ambient medium, the dissipation of which provides the ICM heat source. Through controlled inviscid three-dimensional hydrodynamic simulations, we verify that explosive AGN-like events can launch gravity waves (g-modes) into the ambient ICM, which in turn decays to volume-filling turbulence. In our model, however, this process is found to be inefficient, with less than 1% of the energy injected by the AGN activity actually ending up in the turbulence of the ambient ICM. This efficiency is an order of magnitude or more too small to explain the observations of AGN-feedback in galaxy clusters and groups with short central cooling times. Atmospheres in which the g-modes are strongly trapped/confined have an even lower efficiency since, in these models, the excitation of turbulence relies on the g-modes’ ability to escape from the center of the cluster into the bulk ICM. Our results suggest that, if AGN-induced turbulence is indeed the mechanism by which the AGN heats the ICM core, its driving may rely on physics beyond that captured in our ideal hydrodynamic model.

  10. Probing the circumgalactic medium of active galactic nuclei with background quasars

    NASA Astrophysics Data System (ADS)

    Kacprzak, Glenn G.; Churchill, Christopher W.; Murphy, Michael T.; Cooke, Jeff

    2015-01-01

    We performed a detailed study of the extended cool gas, traced by Mg II absorption [Wr(2796) ≥ 0.3 Å], surrounding 14 narrow-line active galactic nuclei (AGNs) at 0.12 ≤ z ≤ 0.22 using background quasar sightlines. The background quasars probe the AGNs at projected distances of 60 ≤ D ≤ 265 kpc. We find that, between 100 ≤ D ≤ 200 kpc, AGNs appear to have lower Mg II gas covering fractions (0.09^{+0.18}_{-0.08}) than quasars (0.47^{+0.16}_{-0.15}) and possibly lower than inactive field galaxies (0.25^{+0.11}_{-0.09}). We do not find a statistically significant azimuthal angle dependence for the Mg IIcovering fraction around AGNs, though the data hint at one. We also study the `down-the-barrel' outflow properties of the AGNs themselves and detect intrinsic Na ID absorption in 8/8 systems and intrinsic Mg II absorption in 2/2 systems, demonstrating that the AGNs have significant reservoirs of cool gas. We find that 6/8 Na ID and 2/2 Mg II intrinsic systems contain blueshifted absorption with Δv > 50 km s-1, indicating outflowing gas. The 2/2 intrinsic Mg II systems have outflow velocities a factor of ˜4 higher than the Na ID outflow velocities. Our results are consistent with AGN-driven outflows destroying the cool gas within their haloes, which dramatically decreases their cool gas covering fraction, while starburst-driven winds are expelling cool gas into their circumgalactic media (CGM). This picture appears contrary to quasar-quasar pair studies which show that the quasar CGM contains significant amounts of cool gas whereas intrinsic gas found `down-the-barrel' of quasars reveals no cool gas. We discuss how these results are complementary and provide support for the AGN unified model.

  11. Elastic Proton Scattering of Medium Mass Nuclei from Coupled-Cluster Theory

    SciTech Connect

    Hagen, G.; MichelN.,

    2012-01-01

    Using coupled-cluster theory and interactions from chiral effective field theory, we compute overlap functions for transfer and scattering of low-energy protons on the target nucleus 40Ca. Effects of three-nucleon forces are included phenomenologically as in-medium two-nucleon interactions. Using known asymptotic forms for one-nucleon overlap functions we derive a simple and intuitive way of computing scattering observables such as elastic scattering phase shifts and cross sections. As a first application and proof of principle, we compute phase shifts and differential interaction cross sections at energies of 9.6 and 12.44 MeV and compare with experimental data. Our computed diffraction minima are in fair agreement with experimental results, while we tend to overestimate the cross sections at large scattering angles.

  12. Improved version of a binding energy formula for heavy and superheavy nuclei with Z{>=}90 and N{>=}140

    SciTech Connect

    Dong Tiekuang; Ren Zhongzhou

    2008-06-15

    A local formula of binding energy for heavy and superheavy nuclei has very recently been proposed [Dong and Ren, Phys. Rev. C 72, 064331 (2005)]. In this paper, the limit of the predictive ability of this local formula is investigated. It is found that the neutron-proton correlations should be considered when higher precision is required. On the one hand, we introduce a new term |N-Z-50|/A, and on the other hand we consider the different strengths of proton-proton, neutron-neutron, and neutron-proton pairing correlations. For the first time, the standard deviation {radical}({sigma}{sup 2}) of the binding energies for 117 nuclei with Z{>=}90 and N{>=}140 is reduced to 0.105 MeV. The {alpha} decay energies Q{sub {alpha}} and half-lives T{sub {alpha}} of nuclei with Z=102-118 are reproduced quite well. The proton drip line of superheavy elements from Md (Z=101) to Ds (Z=110) are predicted.

  13. Extending studies of the fusion of heavy nuclei to the neutron rich region using accelerated radioactive ion beams.

    SciTech Connect

    Shapira, Dan

    2011-01-01

    One of the stated goals for proposed and existing facilities that produce and accelerate radioactive ion beams is to explore and achieve a new understanding of the reactions mechanisms leading to the synthesis of the heaviest nuclei. Nuclear synthesis of two large nuclei into a single entity is a complex multistep process. The beam intensities of radioactive ions accelerated at present day facilities are not sufficient to synthesize super heavy elements. However the study of the iso-spin dependence of nuclear synthesis and the many processes competing with it can be carried out at present day facilities. Of special interest are cases where the interacting nuclei and the synthesized product are extremely neutron-rich. The effects of neutron excess on the reaction processes leading to the formation of the synthesized nucleus that emerged in earlier studies are poorly understood and sometimes counter intuitive. Results from measurements performed at HRIBF, as well as our plans for future measurements and the equipment being prepared will be presented.

  14. Dose to tissue medium or water cavities as surrogate for the dose to cell nuclei at brachytherapy photon energies.

    PubMed

    Enger, Shirin A; Ahnesjö, Anders; Verhaegen, Frank; Beaulieu, Luc

    2012-07-21

    It has been suggested that modern dose calculation algorithms should be able to report absorbed dose both as dose to the local medium, D(m,m,) and as dose to a water cavity embedded in the medium, D(w,m), using conversion factors from cavity theory. Assuming that the cell nucleus with its DNA content is the most important target for biological response, the aim of this study is to investigate, by means of Monte Carlo (MC) simulations, the relationship of the dose to a cell nucleus in a medium, D(n,m,) to D(m,m) and D(w,m), for different combinations of cell nucleus compositions and tissue media for different photon energies used in brachytherapy. As D(n,m) is very impractical to calculate directly for routine treatment planning, while D(m,m) and D(w,m) are much easier to obtain, the questions arise which one of these quantities is the best surrogate for D(n,m) and which cavity theory assumptions should one use for its estimate. The Geant4.9.4 MC code was used to calculate D(m,m,) D(w,m) and D(n,m) for photon energies from 20 (representing the lower energy end of brachytherapy for ¹⁰³Pd or ¹²⁵I) to 300 keV (close to the mean energy of (¹⁹²Ir) and for the tissue media adipose, breast, prostate and muscle. To simulate the cell and its nucleus, concentric spherical cavities were placed inside a cubic phantom (10 × 10 × 10 mm³). The diameter of the simulated nuclei was set to 14 µm. For each tissue medium, three different setups were simulated; (a) D(n,m) was calculated with nuclei embedded in tissues (MC-D(n,m)). Four different published elemental compositions of cell nuclei were used. (b) D(w,m) was calculated with MC (MC-D(w,m)) and compared with large cavity theory calculated D(w,m) (LCT-D(w,m)), and small cavity theory calculated D(w,m) (SCT-D(w,m)). (c) D(m,m) was calculated with MC (MC-D(m,m)). MC-D(w,m) is a good substitute for MC-D(n,m) for all photon energies and for all simulated nucleus compositions and tissue types. SCT-D(w,m) can be used

  15. Isotopic dependence of fusion cross sections in reactions with heavy nuclei

    NASA Astrophysics Data System (ADS)

    Adamian, G. G.; Antonenko, N. V.; Scheid, W.

    2000-09-01

    The dependence of fusion cross section on the isotopic composition of colliding nuclei is analysed within the dinuclear system concept for compound nucleus formation. Probabilities of fusion and surviving probabilities, ingredients of the evaporation residue cross sections, depend decisively on the neutron numbers of the dinuclear system. Evaporation residue cross sections for the production of actinides and superheavy nuclei, listed in table form, are discussed and compared with existing experimental data. In the Pb-based reactions neutron-rich radioactive projectiles are shown to lead to similar fusion cross sections as stable projectiles.

  16. Tracks of heavy and superheavy cosmic nuclei in olivines of extraterrestrial origin

    NASA Astrophysics Data System (ADS)

    Ignatova, R.; Lkhagvasuren, D.; Otgonsuren, O.; Pellas, P.; Pereligin, V.; Pero, K.; Stetsenko, S.; Taneva, T.; Iadav, D.

    The results of a study of the tracks of galactic nulei with X equal to or greater than 50 are reviewed with particular reference to an analysis of meteoritic olivine samples using an annealing technique. More than 500 tracks of nuclei with Z equal to or greater than 50 have been detected, including three tracks that are 1.5-1.8 times longer than those of uranium and thorium. These tracks are thought to belong to nuclei with Z of not less than 110.

  17. Next-Generation Facilities for the Research with Exotic Nuclei and Super-Heavy Elements

    NASA Astrophysics Data System (ADS)

    Scheidenberger, Christoph

    The present decade is governed by the construction and advent of new, dedicated radioactive beam facilities in several continents. These forthcoming facilities will allow to explore hitherto unknown territory in the chart of nuclei and to study new phenomena, effects and structural features in exotic nuclei. Increasing intensity of primary and secondary beams, selective and efficient separation techniques adapted to the reaction mechanisms and production methods, and sensitive instruments and detectors are the key prerequisites for new findings and exploratory measurements. The new facilities and instruments will enhance the science potential tremendously.

  18. Development of a medium-energy superconducting heavy-ion linac.

    SciTech Connect

    Ostroumov, P. N.; Physics

    2002-03-01

    The Rare Isotope Accelerator (RIA) facility project includes a cw 1.4 GeV driver linac and a 100 MV postaccelerator both based on superconducting (SC) cavities operating at frequencies from 48 to 805 MHz. In these linacs more than 99% of the total voltage is provided by SC cavities. An initial acceleration is provided by room temperature radio frequency quadrupoles. The driver linac is designed for acceleration of any ion species, from protons up to 900 MeV to uranium up to 400 MeV/u. The novel feature of the driver linac is an acceleration of multiple charge-state heavy-ion beams in order to achieve 400 kW beam power. This paper presents design features of a medium-energy SC heavy-ion linac taking the RIA driver linac as an example. The dynamics of single and multiple charge-state beams are detailed, including the effects of possible errors in rf field parameters and misalignments of transverse focusing elements. The important design considerations of such linac are presented. Several new conceptual solutions in beam dynamics in SC accelerating structures for heavy-ion applications are discussed.

  19. Symbiotic starburst-black hole active galactic nuclei - I. Isothermal hydrodynamics of the mass-loaded interstellar medium

    NASA Astrophysics Data System (ADS)

    Williams, R. J. R.; Baker, A. C.; Perry, Judith J.

    1999-12-01

    Compelling evidence associates the nuclei of active galaxies and massive starbursts. The symbiosis between a compact nuclear starburst stellar cluster and a massive black hole can self-consistently explain the properties of active nuclei. The young stellar cluster has a profound effect on the most important observable properties of active galaxies through its gravity, and by mass injection through stellar winds, supernovae and stellar collisions. This mass loss, injected throughout the nucleus, creates a hot nuclear interstellar medium (nISM). The cluster both acts as an optically thin fuel reservoir and enriches the nISM with the products of nucleosynthesis. The nISM flows under gravitational and radiative forces until it leaves the nucleus or is accreted on to the black hole or accretion disc. The radiative force exerted by the black hole-accretion disc radiation field is not spherically symmetric. This results in complex flows in which regions of inflow can coexist with high Mach number outflowing winds and hydrodynamic jets. We present two-dimensional hydrodynamic models of such nISM flows, which are highly complex and time-variable. Shocked shells, jets and explosive bubbles are produced, with bipolar winds driving out from the nucleus. Our results graphically illustrate why broad-emission-line studies have consistently failed to identify any simple, global flow geometry. The real structure of the flows is inevitably yet more complex. The structure of these nISM flows is principally determined by two dimensionless quantities. The first is the magnitude of the stellar cluster velocity dispersion relative to the sound speed in the nISM. These speeds measure the gravitational and thermal energies in the nISM respectively, and, therefore, whether the gas is initially bound or escapes in a thermal wind. The second parameter is the Mach number of the ill-collimated nISM flow which is driven away from the central black hole. We discuss a two-parameter classification

  20. Debye Layer Confinement of Nucleons in Nuclei for Heavy Nuclear Synthesis

    SciTech Connect

    Ghahramany, N.; Ghanaatian, M.

    2008-04-21

    Following the laser ablation studies leading to a theory of nuclei confinement by a Debye layer mechanism, we present here numerical evaluations for the known stable nuclei where the Coulomb repulsion is included as a rather minor component especially for lager nuclei. It is noticed that the well known empirical nuclear density of 2x10{sup 38} cm{sup -3} follows for a nucleon number A<60 for iron. The crucial change of the Fermi energy into the relativistic branch for the nucleons results for a density at 3x10{sup 39} cm{sup -3} which density corresponds to the Debye layer equilibrium near uranium above which the Fermi energy will not permit any nucleation. It is speculated whether the range between both densities at the big bang expansion at temperatures of few 100 keV and at 200 seconds after the big bang is resulting in a nuclear-chemical Boltzmann equilibrium for the generation of the endothermic nuclear generation. The question is then open, what additional nuclear expansion forces are acting in the elements between uranium and iron during this equilibrium reactions in nuclei such that the empirical nuclear density is produced.

  1. Modeling Heavy/Medium-Duty Fuel Consumption Based on Drive Cycle Properties

    SciTech Connect

    Wang, Lijuan; Duran, Adam; Gonder, Jeffrey; Kelly, Kenneth

    2015-10-13

    This paper presents multiple methods for predicting heavy/medium-duty vehicle fuel consumption based on driving cycle information. A polynomial model, a black box artificial neural net model, a polynomial neural network model, and a multivariate adaptive regression splines (MARS) model were developed and verified using data collected from chassis testing performed on a parcel delivery diesel truck operating over the Heavy Heavy-Duty Diesel Truck (HHDDT), City Suburban Heavy Vehicle Cycle (CSHVC), New York Composite Cycle (NYCC), and hydraulic hybrid vehicle (HHV) drive cycles. Each model was trained using one of four drive cycles as a training cycle and the other three as testing cycles. By comparing the training and testing results, a representative training cycle was chosen and used to further tune each method. HHDDT as the training cycle gave the best predictive results, because HHDDT contains a variety of drive characteristics, such as high speed, acceleration, idling, and deceleration. Among the four model approaches, MARS gave the best predictive performance, with an average absolute percent error of -1.84% over the four chassis dynamometer drive cycles. To further evaluate the accuracy of the predictive models, the approaches were first applied to real-world data. MARS outperformed the other three approaches, providing an average absolute percent error of -2.2% of four real-world road segments. The MARS model performance was then compared to HHDDT, CSHVC, NYCC, and HHV drive cycles with the performance from Future Automotive System Technology Simulator (FASTSim). The results indicated that the MARS method achieved a comparative predictive performance with FASTSim.

  2. Electron-positron pairs in physics and astrophysics: From heavy nuclei to black holes

    NASA Astrophysics Data System (ADS)

    Ruffini, Remo; Vereshchagin, Gregory; Xue, She-Sheng

    2010-02-01

    Due to the interaction of physics and astrophysics we are witnessing in these years a splendid synthesis of theoretical, experimental and observational results originating from three fundamental physical processes. They were originally proposed by Dirac, by Breit and Wheeler and by Sauter, Heisenberg, Euler and Schwinger. For almost seventy years they have all three been followed by a continued effort of experimental verification on Earth-based experiments. The Dirac process, e+e-→2γ, has been by far the most successful. It has obtained extremely accurate experimental verification and has led as well to an enormous number of new physics in possibly one of the most fruitful experimental avenues by introduction of storage rings in Frascati and followed by the largest accelerators worldwide: DESY, SLAC etc. The Breit-Wheeler process, 2γ→e+e-, although conceptually simple, being the inverse process of the Dirac one, has been by far one of the most difficult to be verified experimentally. Only recently, through the technology based on free electron X-ray laser and its numerous applications in Earth-based experiments, some first indications of its possible verification have been reached. The vacuum polarization process in strong electromagnetic field, pioneered by Sauter, Heisenberg, Euler and Schwinger, introduced the concept of critical electric field Ec=me2c3/(eħ). It has been searched without success for more than forty years by heavy-ion collisions in many of the leading particle accelerators worldwide. The novel situation today is that these same processes can be studied on a much more grandiose scale during the gravitational collapse leading to the formation of a black hole being observed in Gamma Ray Bursts (GRBs). This report is dedicated to the scientific race. The theoretical and experimental work developed in Earth-based laboratories is confronted with the theoretical interpretation of space-based observations of phenomena originating on cosmological

  3. Quantifying Light, Medium, and Heavy Crude Oil Distribution in Homogeneous Porous Media

    NASA Astrophysics Data System (ADS)

    Ghosh, J.; Tick, G. R.

    2008-12-01

    Crude oil recovery is highly dependent upon the physical heterogeneity of media and resulting distribution of the oil-phase within the pore spaces. Factors such as capillary force, the geometry of the pore spaces, and interfacial tension between the oil blobs and water-wet porous media will ultimately control the recovery process. Pore scale studies were conducted to study the distribution and the morphology of various fractions of crude oil in increasingly heterogeneous porous media. In addition, experiments were also carried out to characterize the temporal changes in distribution and morphology of the oil phase after a series of surfactant flooding events. Specifically, columns were packed with three different porous media with increasing heterogeneity and distributed with three different fractions (light, medium, and heavy) of crude oil. The columns were imaged using synchrotron X-ray microtomography before and after a series of surfactant floods to quantify the resulting crude oil distributions over time. Preliminary results show that the light crude oil was more heterogeneously distributed than the medium fraction crude oil within the same porous media type both before and throughout the series of surfactant floods. It was also observed that approximately 95% of the medium fraction crude oil blob-size distribution was smaller (<0.0008 cu mm) than that of the light crude oil, encompassing a significant number of blob singlets. The lighter crude oil fraction has the median blob diameter approximately 20 times greater than that of the medium crude oil fraction. These results further reveal that that oil extraction and recovery is highly dependent upon the oil fraction, the presence of small- sized blob singlets, and the resulting distributions present within porous media before and during surfactant flooding. This research will not only be helpful in understanding the factors controlling crude oil mobilization at the pore scale but also test the utility of

  4. Nilsson-SU3 self-consistency in heavy N =Z nuclei

    NASA Astrophysics Data System (ADS)

    Zuker, A. P.; Poves, A.; Nowacki, F.; Lenzi, S. M.

    2015-08-01

    It is argued that there exist natural shell-model spaces optimally adapted to the operation of two variants of Elliott's SU3 symmetry that provide accurate predictions of quadrupole moments of deformed states. A self-consistent Nilsson-like calculation describes the competition between the realistic quadrupole force and the central field, indicating a remarkable stability of the quadrupole moments—which remain close to their quasi- and pseudo-SU3 values—as the single-particle splittings increase. A detailed study of the N =Z even nuclei from 56Ni to 96Cd reveals that the region of prolate deformation is bounded by a pair of transitional nuclei 72Kr and 84Mo in which prolate ground-state bands are predicted to dominate, though coexisting with oblate ones.

  5. Studies of the shapes of heavy pear-shaped nuclei at ISOLDE

    NASA Astrophysics Data System (ADS)

    Butler, P. A.

    2016-07-01

    For certain combinations of protons and neutrons there is a theoretical expectation that the shape of nuclei can assume octupole deformation, which would give rise to reflection asymmetry or a "pear-shape" in the intrinsic frame, either dynamically (octupole vibrations) or statically (permanent octupole deformation). I will briefly review the historic evidence for reflection asymmetry in nuclei and describe how recent experiments carried out at REX-ISOLDE have constrained nuclear theory and how they contribute to tests of extensions of the Standard Model. I will also discuss future prospects for measuring nuclear shapes from Coulomb Excitation: experiments are being planned that will exploit beams from HIE-ISOLDE that are cooled in the TSR storage ring and injected into a solenoidal spectrometer similar to the HELIOS device developed at the Argonne National Laboratory.

  6. Study of near-stability nuclei populated as fission fragments in heavy-ion fusion reactions

    SciTech Connect

    Fotiadis, Nikolaos; Nelson, Ronald O; Devlin, Matthew; Cizewski, Jolie A; Krucken, Reiner; Clark, R M; Fallon, Paul; Lee, I Yang; Macchiavelli, Agusto O; Becker, John A; Younes, Walid

    2010-01-01

    Examples are presented to illustrate the power of prompt {gamma}-ray spectroscopy of fission fragments from compound nuclei with A {approx} 200 formed in fusion-evaporation reactions in experiments using the Gammasphere Ge-detector array. Complementary methods, such as Coulomb excitation and deep-inelastic processes, are also discussed. In other cases (n, xn{gamma}) reactions on stable isotopes have been used to establish neutron excitation functions for {gamma}-rays using a pulsed 'white'-neutron source, coupled to a high-energy-resolution germanium-detector array. The excitation functions can unambiguously assign {gamma}-rays to a specific reaction product. Results from all these methods bridge the gaps in the systematics of high-spin states between the neutron-deficient and neutron-rich nuclei. Results near shell closures should motivate new shell model calculations.

  7. Processing Code System for Production of Group Constants of Heavy Resonant Nuclei.

    Energy Science and Technology Software Center (ESTSC)

    1981-06-11

    Version 00 TIMS-1 calculates the infinitely dilute group cross sections and the temperature dependent self-shielding factors for arbitrary values of sigma0 and R where sigma0 is the effective background cross section of potential scattering and R the ratio of the atomic number densities for two resonant nuclei, if any. TIMS-1 is specifically programmed to use the evaluated nuclear data file of ENDF/B or JENDL as input data.

  8. Behavior of one-quasiparticle levels in odd isotonic chains of heavy nuclei

    SciTech Connect

    Adamian, G. G.; Antonenko, N. V.; Kuklin, S. N.; Malov, L. A.; Lu, B. N.; Zhou, S. G.

    2011-08-15

    The low-lying one-quasiparticle states are studied in the isotonic chains with N=147, 149, 151, 153, and 155 within the microscopic-macroscopic and self-consistent approaches. The energies of one-quasiparticle states change rather smoothly in the isotonic chains if there is no cross of the proton subshell. The {alpha}-decay schemes of several nuclei are suggested. The isomeric states in the odd isotopes of Fm and No are discussed.

  9. Prototyping of beam position monitor for medium energy beam transport section of RAON heavy ion accelerator

    NASA Astrophysics Data System (ADS)

    Jang, Hyojae; Jin, Hyunchang; Jang, Ji-Ho; Hong, In-Seok

    2016-02-01

    A heavy ion accelerator, RAON is going to be built by Rare Isotope Science Project in Korea. Its target is to accelerate various stable ions such as uranium, proton, and xenon from electron cyclotron resonance ion source and some rare isotopes from isotope separation on-line. The beam shaping, charge selection, and modulation should be applied to the ions from these ion sources because RAON adopts a superconducting linear accelerator structure for beam acceleration. For such treatment, low energy beam transport, radio frequency quadrupole, and medium energy beam transport (MEBT) will be installed in injector part of RAON accelerator. Recently, development of a prototype of stripline beam position monitor (BPM) to measure the position of ion beams in MEBT section is under way. In this presentation, design of stripline, electromagnetic (EM) simulation results, and RF measurement test results obtained from the prototyped BPM will be described.

  10. Damage Processes In MgO Irradiated With Medium-energy Heavy Ions

    SciTech Connect

    Moll, Sandra J.; Zhang, Y.; Debelle, A.; Thome, Lionel; Crocombette, J.-P.; Zhu, Zihua; Jagielski, Jacek; Weber, William J.

    2015-04-01

    The micro-structural modifications produced in MgO single crystals exposed to medium-energy heavy ions (1.2-MeV Au) were investigated using Rutherford backscattering spectrometry in channeling geometry coupled to Monte-Carlo analyses, secondary ion mass spectrometry, X-ray diffraction and transmission electron microscopy. The damage accumulation and the elastic strain variation were interpreted in the framework of the multi-step damage accumulation (MSDA) model. Both build-ups follow a multi-step process similar to that recently observed for ion-irradiated yttria-stabilized zirconia (YSZ) single crystals. However, in MgO, an unexpectedly high disorder level occurs far beyond the theoretical damage distribution. These results strongly suggest that the migration of defects created in the near-surface layer is most likely at the origin of the broadening of the damage depth distribution in MgO.

  11. Reaction studies near the barrier for medium heavy systems: Ni + Sn

    SciTech Connect

    Henning, W.

    1985-01-01

    Cross sections for elastic and inelastic scattering, single- and multi-nucleon transfer, fusion followed by particle evaporation leaving an evaporation residue, and fusion followed by fission have been measured for /sup 58/ /sup 64/Ni beams incident on even Sn targets at energies from below to above the Coulomb barrier. The Ni beams were provided by the Argonne Superconducting Linac. The aim of these measurements is a comprehensive study of the reaction systematics in a medium-heavy collision system. At present, a small fraction of the data has been fully analyzed and published, a larger part is presently being compared to model calculations. Some of the data needs to be confirmed by additional measurements. This summary should be viewed as a status report and an attempt to formulate some of the open questions. 9 references.

  12. Prototyping of beam position monitor for medium energy beam transport section of RAON heavy ion accelerator.

    PubMed

    Jang, Hyojae; Jin, Hyunchang; Jang, Ji-Ho; Hong, In-Seok

    2016-02-01

    A heavy ion accelerator, RAON is going to be built by Rare Isotope Science Project in Korea. Its target is to accelerate various stable ions such as uranium, proton, and xenon from electron cyclotron resonance ion source and some rare isotopes from isotope separation on-line. The beam shaping, charge selection, and modulation should be applied to the ions from these ion sources because RAON adopts a superconducting linear accelerator structure for beam acceleration. For such treatment, low energy beam transport, radio frequency quadrupole, and medium energy beam transport (MEBT) will be installed in injector part of RAON accelerator. Recently, development of a prototype of stripline beam position monitor (BPM) to measure the position of ion beams in MEBT section is under way. In this presentation, design of stripline, electromagnetic (EM) simulation results, and RF measurement test results obtained from the prototyped BPM will be described. PMID:26932088

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

    NASA Astrophysics Data System (ADS)

    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. Experimental investigation of the physical properties of medium and heavy oils, their vaporization and use in explosion engines. Part I

    NASA Technical Reports Server (NTRS)

    Heinlein, Fritz

    1926-01-01

    While little has been accomplished in obtaining an abundant supply of light oils from coal and heavy oils, progress has been made on engine design to make use of the heavier oils. Progress has been made in two different directions which are outlined in this paper: the group of engines with medium and high-pressure carburetion in the cylinder; and the group of engines with low-pressure carburetion of the heavy oils before reaching the cylinder.

  15. Science requirements for Heavy Nuclei Collection (HNC) experiment on NASA Long Duration Exposure Facility (LDEF) Mission 2

    NASA Technical Reports Server (NTRS)

    Price, P. Buford

    1991-01-01

    The Heavy Nuclei Collection (HNC) is a passive array of stacks of a special glass, 14 sheets thick, that record tracks of ultraheavy cosmic rays for later readout by automated systems on Earth. The primary goal is to determine the relative abundances of both the odd- and even-Z cosmic rays with Z equal to or greater than 50 with statistics a factor at least 60 greater than obtained in HEAO-3 and to obtain charge resolution at least as good as 0.25 charge unit. The secondary goal is to search for hypothetical particles such as superheavy elements. The HNC detector array will have a cumulative collection power equivalent to flying 32 sq m of detectors in space for 4 years. The array will be flown as a free-flight spacecraft and/or attached to Space Station Freedom.

  16. Observations of columnal recombination in the ionization tracks of energetic heavy nuclei in an argon-methane gas mixture

    NASA Technical Reports Server (NTRS)

    Wiedenbeck, Mark E.

    1990-01-01

    Measurements of ionization signals resulting from the passage of energetic heavy nuclei through a gas mixture consisting of 95 mol percent Ar plus 5 mol percent CH4, at an absolute pressure of 3 atm are presented. The measurements take place under a uniform electric field perpendicular to the ionization track. The signals were compared to the calculated energy losses, with an assumption of proportionality between energy loss rate and ionization rate. Significant deviations from proportionality are found for energy loss rate grater than about 3000 MeV sq cm/g, while fractional deviations are found to be proportional to the energy loss rate (dE/dx) exp m, where m is equal to about two. These results are attributed to the columnal recombination.

  17. Studies of heavy-ion reactions and transuranic nuclei: Progress report, September 1, 1987--August 31, 1988

    SciTech Connect

    Schroeder, W.U.; Huizenga, J.R.

    1988-08-01

    The effect of successively increasing gradients of the potential energy surface on mass and charge transport was studied experimentally and theoretically with a series of damped reactions induced by /sup 48/Ca, /sup 64/Ni, /sup 58/Ni, and /sup 40/Ca projectiles on /sup 238/U targets. Combined transport-evaporation calculations that were performed for the interpretation of data demonstrate a systematic deficiency of quantitative reaction theory. A new type of experimental method has been employed to study several moments of the energy partition in damped reactions, measuring multiplicity correlations of neutrons emitted from the asymptotic fragments with a specially designed, directionally sensitive multiplicity counter. First results indicate significant departures of damped reaction systems from thermal equilibrium. Employing realistic Monte Carlo simulation of published experiments, it was demonstrated that the directions of net mass transfer and energy deposit are uncorrelated in damped reactions. Evaporative and preequilibrium neutron emission has been studied for the asymmetric heavy-ion system /sup 139/La + /sup 40/Ar. The disequilibrium energy transport phenomena observed in the experiment are quantitatively reproduced by model calculations. A strong impact-parameter dependence of preequilibrium emission is demonstrated. The emission patterns of ..cap alpha.. particles evaporated from high spin compound nuclei, previously attributed to exotic nuclear shapes, have been explained in realistic statistical model calculations for nuclei with conventional shapes. A new octal digital delay module has been designed and tested.

  18. Description of the dipole giant resonance in heavy and superheavy nuclei within Skyrme random-phase approximation

    SciTech Connect

    Kleinig, W.; Nesterenko, V. O.; Kvasil, J.; Vesely, P.; Reinhard, P.-G.

    2008-10-15

    The E1(T=1) isovector dipole giant resonance (GDR) in heavy and superheavy deformed nuclei is analyzed over a sample of 18 rare-earth nuclei, four actinides, and three chains of superheavy elements (Z=102, 114, and 120). The basis of the description is the self-consistent separable random-phase approximation (SRPA) using the Skyrme force SLy6. The model well reproduces the experimental data in the rare-earth and actinide regions. The trend of the resonance peak energies follows the estimates from collective models, showing a bias to the volume mode for the rare-earth isotopes and a mix of volume and surface modes for actinides and superheavy elements. The widths of the GDR are mainly determined by the Landau fragmentation, which in turn is found to be strongly influenced by deformation. A deformation splitting of the GDR can contribute to about one-third of the width, and about 1 MeV further broadening can be associated with mechanisms beyond the SRPA description (e.g., escape widths and coupling with complex configurations)

  19. Fission barriers for Po nuclei produced in complete fusion reactions with heavy ions

    SciTech Connect

    Sagaidak, R. N.; Andreyev, A. N.

    2009-05-15

    Evaporation residues and fission excitation functions obtained in complete fusion reactions leading to Po compound nuclei have been analyzed in the framework of the standard statistical model. Macroscopic fission barriers deduced from the cross-section data analysis are compared with the predictions of various theoretical models and available data. A drop in the Po barriers with the decrease in a neutron number was found, which is stronger than predicted by any theory. The presence of entrance channel effects and collective excitations in the compound nucleus decay is considered as a possible reason for the barrier reduction.

  20. EVIDENCE FOR ANOMALOUS NUCLEI AMONG RELATIVISTIC PROJECTILE FRAGMENTS FROM HEAVY ION COLLISIONS AT BEVALAC ENERGIES

    SciTech Connect

    Friedlander, E.M.; Gimpel, R.W.; Heckman, H.H.; Karant, Y.J.; Judek, B.; Ganssauge, E.

    1980-06-01

    Two independent emulsion experiments using Bevalac beams of {sup 16}O and {sup 56}Fe at {approx}2 GeV/nucleon find with > 99.7% confidence that the reaction mean-free paths of projectile fragments, 3 {approx}< Z {approx}< 26, are shorter for a few centimeters after their emission than at larger distances, or than predicted from experiments on beam nuclei. This effect, which is enhanced in later generations of fragments, can be interpreted by the relatively rare occurrence of fragments that interact with an unexpectedly large cross section.

  1. Forward-backward multiplicity fluctuations in heavy nuclei collisions in the wounded nucleon model

    SciTech Connect

    Bzdak, Adam; Wozniak, Krzysztof

    2010-03-15

    We use the wounded nucleon model to study the forward-backward multiplicity fluctuations measured by the PHOBOS Collaboration in Au + Au collisions at sq root(s{sub N{sub N}})=200 GeV. The enhancement of forward-backward fluctuations in Au + Au collisions with respect to the elementary p+p interactions is explained in this model by the asymmetric shape of the pseudorapidity density of produced particles from a single wounded nucleon and the fluctuations of the number of wounded nucleons in the colliding nuclei. The wounded nucleon model describes these experimental data better than the HIJING, AMPT, or UrQMD models do.

  2. Magnetic dipole moment measurements of picosecond states in even and odd heavy nuclei

    SciTech Connect

    Ballon, D.J.

    1985-01-01

    The perturbed angular correlation transient field technique is used to measure the precession of nuclear magnetic moments of low lying excited states in isotopes of silver, neodymium, samarium, and gadolinium. The precession measurements are used to explore three main areas of study. First, from the measurements made on /sup 150/Sm transversing gadolinium targets, the temperature dependence of the transient hyperfine field is deduced at /sup 150/Sm nuclei traveling at 2 < v/v/sub 0/ < 4. These are compared with similar measurements made using iron targets. Second, the deduced values of the g-factors of the 2/sub 1/ + states in even neodymium, samarium and gadolinium isotopes are discussed in connection with a possible proton shell closure at Z = 64. Third, the deduced values of the g-factors of the 3/2/sub 1/- and 5/2/sub 1/- states of /sup 107,109/Ag are compared to various theoretical predictions in order to explore any simple relationships that may exist between these states and the first 2/sub 1/+ states of neighboring even-even nuclei.

  3. On the charge to mass ratio of neutron cores and heavy nuclei

    SciTech Connect

    Patricelli, B.; Rotondo, M.; Ruffini, R.

    2008-01-03

    We determine theoretically the relation between the total number of protons N{sub p} and the mass number A (the charge to mass ratio) of nuclei and neutron cores with the model recently proposed by Ruffini et al. (2007) and we compare it with other N{sub p} versus A relations: the empirical one, related to the Periodic Table, and the semi-empirical relation, obtained by minimizing the Weizsaecker mass formula. We find that there is a very good agreement between all the relations for values of A typical of nuclei, with differences of the order of per cent. Our relation and the semi-empirical one are in agreement up to A{approx}10{sup 4}; for higher values, we find that the two relations differ. We interprete the different behaviour of our theoretical relation as a result of the penetration of electrons (initially confined in an external shell) inside the core, that becomes more and more important by increasing A; these effects are not taken into account in the semi-empirical mass-formula.

  4. Heavy nuclei far from stability in the N < 126, Z > 82 region

    SciTech Connect

    Back, B.B.; Blumenthal, D.J.; Carpenter, M.P.

    1995-08-01

    There are long-standing calculations suggesting that nuclei in the N < 126, Z > 82 region far from stability exhibit deformation effects. Away from stability an observable permanent quadrupole deformation should be achieved but, as yet, there is no experimental evidence for such an effect. A series of experiments was performed to assess the production of nuclei in this region and to study their structure. These experiments were performed using gamma-ray spectroscopy to investigate the low-lying level schemes and alpha-particle spectroscopy in order to isolate fine structure in the decay. The low-lying level structure of the neutron-deficient isotope {sup 202}Rn was studied, for the first time, using the {sup 181}Ta({sup 27}Al,6n) and {sup 192}Pt({sup 16}O,6n) reactions. Gamma-ray transitions between excited states in {sup 202}Rn were identified by mass tagging the Fragment Mass Analyzer and by observation of coincident X rays. Transitions in {sup 203}Rn were also identified. The level scheme deduced from these data is consistent with the systematics of light radon isotopes below the N = 126 shell closure and with theoretical calculations indicating that the ground-state shape should not be strongly deformed at N = 116.

  5. Non-Axial Octupole Deformations and Tetrahedral Symmetry in Heavy Nuclei

    SciTech Connect

    Mazurek, Katarzyna; Dudek, Jerzy

    2005-11-21

    The total energies of about 120 nuclei in the Thorium region have been calculated within the macroscopic-microscopic method in the 5-dimensional space of deformation parameters {alpha}20, {alpha}22, {alpha}30, {alpha}32 and {alpha}40. The macroscopic energy term contains the nuclear surface-curvature dependence as proposed within the LSD approach. The microscopic energies are calculated with the Woods-Saxon single particle potential employing the universal set of parameters.We study a possible presence of the octupole axial and non-axial degrees of freedom all-over in the ({beta}, {gamma})-plane focussing on the ground-states, secondary minima and in the saddle points. In fact, a competition between axial and tri-axial octupole deformation parameters is obtained at the saddle points and in the secondary minima for many isotones with N > 136. The presence of the tetrahedral symmetry minima is predicted in numerous nuclei in the discussed region, although most of the time at relatively high excitation energies.

  6. Studies of heavy-ion reactions and transuranic nuclei. Progress report, September 1, 1992--August 31, 1993

    SciTech Connect

    Schroeder, W.U.

    1993-08-01

    This report contain papers on the following topics: The Cold-Fusion Saga; Decay Patterns of Dysprosium Nuclei Produced in {sup 32}S + {sup 118,124}Sn Fusion Reactions; Unexpected Features of Reactions Between Very Heavy Ions at Intermediate Bombarding Energies; Correlations Between Neutrons and Charged Products from the Dissipative Reaction {sup 197}Au+{sup 208}Pb at E/A = 29 MeV; Dissipative Dynamics of Projectile-Like Fragment Production in the Reaction {sup 209}Bi+{sup 136}Xe at E/A = 28.2 MeV; Dynamical Production of Intermediate-Mass Fragments in Peripheral {sup 209}Bi+{sup 136}Xe Collisions at E{sub lab}/A = 28.2 MeV; The Rochester 960-Liter Neutron Multiplicity Meter; A Simple Pulse Processing Concept for a Low-Cost Pulse-Shape-Based Particle Identification; A One-Transistor Preamplifier for PMT Anode Signals; A Five-Channel Multistop TDC/Event Handler for the SuperBall Neutron Multiplicity Meter; Construction of the SuperBall -- a 16,000-Liter Neutron Detector for Calorimetric Studies of Intermediate-Energy Heavy-Ion Reactions; A Computer Code for Light Detection Efficiency Calculations for Photo-multipliers of a Neutron Detector; Evaluation of Gd-Loaded Liquid Scintillators for the SuperBall Neutron Calorimeter; and Measurement of the Interaction of Cosmic-Ray {mu}{sup {minus}} with a Muon Telescope.

  7. Studies of heavy ion reactions and transuranic nuclei. Progress report, September 1, 1985-August 31, 1986

    SciTech Connect

    Huizenga, J.R.; Schroeder, W.U.

    1986-08-01

    Progress is reported of research directed to explore nuclear relaxation and transport phenomena induced in heavy-ion collisions, in the range from near-barrier energies to more than 20 MeV per nucleon above the interaction barrier. Transport processes studied include the redistribution of kinetic energy of relative motion and of linear momentum as well as the gradual relaxation of various conditions of a colliding heavy-ion system, initially far from thermodynamic equilibrium, towards a uniform population of phase space. And, finally, they include the stochastic, equilibrium, and nonequilibrium patterns of nuclear disintegration. The group activities range from design of hardware to theoretical modeling. 112 refs., 56 figs., 6 tabs.

  8. True ternary fission of superheavy nuclei

    SciTech Connect

    Zagrebaev, V. I.; Karpov, A. V.; Greiner, Walter

    2010-04-15

    True ternary fission with formation of a heavy third fragment is quite possible for superheavy nuclei because of the strong shell effects leading to a three-body clusterization with the two doubly magic tinlike cores. The simplest way to discover this phenomenon in the decay of excited superheavy nuclei is a detection of two tinlike clusters with appropriate kinematics in low-energy collisions of medium-mass nuclei with actinide targets. The three-body quasi-fission process could be even more pronounced for giant nuclear systems formed in collisions of heavy actinide nuclei. In this case a three-body clusterization might be proved experimentally by the detection of two coincident leadlike fragments in low-energy U + U collisions.

  9. LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray A04

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray A04 EL-1994-00089 LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray A04 The flight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken while the LDEF was attached to the Orbiter's RMS arm prior to berthing in the Orbiter's cargo bay. The white paint dots on the center clamp blocks of the experiment trays left flange and lower flange appear to be discolored by a dark brown stain. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays upper flange is a copper coated pressure sensitive tape used to provide an electrical ground between the experiments thermal cover and the LDEF structure. The UHCRE thermal cover appears to be specular and

  10. LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray B05

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray B05 EL-1994-00088 LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray B05 The flight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken while the LDEF was attached to the Orbiter's RMS arm prior to berthing in the Orbiter's cargo bay. The white paint dots on the center clamp block of the experiment trays lower flange appears to be discolored by a dark brown stain. The tray flanges also appear to be discolored but with a lighter stain. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays upper flange is a copper coated pressure sensitive tape used to provide an electrical ground between the experiments thermal cover and the LDEF

  11. LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray A04

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray A04 EL-1994-00391 LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray A04 The postflight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken in SAEF II at KSC prior to removal of the experiment tray from the LDEF. The paint dots on the experiment tray clamp blocks, originally white, appearsDE:to be discolored by a brown stain. The experiment tray flanges also appear to be coated but with a lighter colored stain. The UHCRE detectors were contained in 16 peripheral LDEF trays with at leastDE:one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays lower flange is a copper coated pressure sensitive tape used to provide an electrical ground between the experiments thermal cover and the LDEF structure. The

  12. LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray D05

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray D05 EL-1994-00311 LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray D05 The postflight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken in SAEF II at KSC after removal of the experiment tray from the LDEF. The experiment tray flanges appear discolored by a brown stain. Outlines of experiment tray clamp blocks are clearly visible on the upper and lower tray flanges. The experiment tray holding fixture hardware covers the clamp block areas on the end flanges. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays lower flange is a copper coated pressure sensitive tape used to provide an electrical ground between the

  13. LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray C08

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray C08 EL-1994-00661 LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray C08 The flight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken while the LDEF was attached to the Orbiter's RMS arm prior to berthing in the Orbiter's cargo bay. The white paint dots on the center clamp block of the experiment trays upper flange and the right end of the experiment trays lower flange appear to be slightly discolored. The tray flanges appear to be discolored by a light brown stain and the ground strap located in the center of the lower flange appears intact but a much darker copper color than in the prelaunch photograph. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored

  14. LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray E02

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray E02 EL-1994-00385 LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray E02 The postflight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken in SAEF II at KSC prior to removal of the experiment tray from the LDEF. The white paint dot on the experiment tray clamp blocks located at the center of the trays lower and left flanges and at the right end of the trays upper flange appear to be discolored by a brown stain. The experiment tray flanges also appear to be coated but with a lighter colored stain. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays lower flange is a copper coated pressure sensitive tape used to provide an

  15. LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray A04

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray A04 EL-1994-00272 LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray A04 The postflight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken in SAEF II at KSC after the experiment tray was removed from the LDEF and the silvered TEFLON® thermal cover removed. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. A copper coated pressure sensitive tape was used to provide an electrical ground strap between the thermal cover and the LDEF structure. All experiment hardware appears to be in prelaunch condition and securely in place. The three cylindrical pressure vessels containing the experiment detectors are shown mounted in the experiment tray with the frame for mounting the

  16. LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray B05

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray B05 EL-1994-00184 LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray B05 The postflight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken in SAEF II at KSC prior to removal of the experiment tray from the LDEF. The paint dots on the experiment tray clamp blocks, originally white, appears to be discolored by a brown stain. The experiment tray flanges also appear to be coated but with a lighter colored stain. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays lower flange is a copper coated pressure sensitive tape used to provide an electrical ground between the experiments thermal cover and the LDEF structure. The UHCRE

  17. LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray C06

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray C06 EL-1994-00206 LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray C06 The postflight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken in SAEF II at KSC after removal of the experiment tray from the LDEF. The experiment tray flanges appear discolored by a light brown stain. Outlines of experiment tray clamp blocks are clearly visible on the lower tray flanges.The experiment tray holding fixture hardware covers the clamp block areas on the end flanges. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays upper flange is a copper coated pressure sensitive tape used to provide an electrical ground between the experiments

  18. LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray A02

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray A02 EL-1994-00387 LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray A02 The postflight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken in SAEF II at KSC prior to removal of the experiment tray from the LDEF. The white paint dot on the experiment tray clamp blocks located at the center of the trays upper and right flanges and at the left end of the trays lower flange appear to be discolored by a brown stain. The experiment tray flanges also appear to be coated but with a lighter colored stain. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar with a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays lower flange is a copper coated pressure sensitive tape used to provide an

  19. LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray E02

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray E02 EL-1994-00131 LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray E02 The flight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken while the LDEF was attached to the Orbiter's RMS arm prior to berthing in the Orbiter's cargo bay. The white paint dots on the center clamp blocks of the experiment trays left flange and lower flange appear to be slightly discolored. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays lower flange is a copper coated pressure sensitive tape used to provide an electrical ground between the experiments thermal cover and the LDEF structure. The UHCRE thermal cover appears to be intact with out visible

  20. LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray C05

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray C05 EL-1994-00205 LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray C05 The postflight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken in SAEF II at KSC after removal of the experiment tray from the LDEF. The experiment tray flanges appear discolored by a brown stain that provides outlines of the experiment tray clamp blocks that are clearly visible on the upper and lower tray flanges.The experiment tray holding fixture hardware covers the clamp block areas on the end flanges. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays lower flange is a copper coated pressure sensitive tape used to provide an electrical ground

  1. LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray A10

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray A10 EL-1994-00122 LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray A10 The postflight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken in the Orbiter Processing Facility (OPF) at KSC during removal of the LDEF from the Orbiters cargo bay. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays upper flange is a copper coated pressure sensitive tape used to provide an electrical ground between the experiments thermal cover and the LDEF structure. The UHCRE thermal covers surface appears to have changed from specular to opaque (glossy white) with many black dots of various sizes that appear to be impact craters. An impact

  2. LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray E10

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray E10 EL-1994-00019 LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray E10 The flight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken while the LDEF was attached to the Orbiter's RMS arm prior to berthing in the Orbiter's cargo bay. The white paint dots on the center clamp blocks of the experiment trays left flange and lower flange appear to be slightly discolored. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays lower flange is a copper coated pressure sensitive tape used to provide an electrical ground between the experiments thermal cover and the LDEF structure. The UHCRE thermal covers surface appears to have changed from

  3. LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray E10

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray E10 EL-1994-00162 LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray E10 The postflight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken in the Orbiter Processing Facility during removal of the LDEF from the Orbiter's payload bay. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays lower flange is a copper coated pressure sensitive tape used to provide an electrical ground between the experiments thermal cover and the LDEF structure. The UHCRE thermal covers surface appears to have changed from specular to opaque with numerous black dots of various sizes that appear to be impact craters. Many of the craters appear to have

  4. Production of medium-mass neutron-rich nuclei in reactions induced by {sup 136}Xe projectiles at 1 A GeV on a beryllium target

    SciTech Connect

    Benlliure, J.; Fernandez-Ordonez, M.; Casarejos, E.; Pereira, J.; Audouin, L.; Rejmund, F.; Stephan, C.; Tassan-Got, L.

    2008-11-15

    Production cross sections of medium-mass neutron-rich nuclei obtained in the fragmentation of {sup 136}Xe projectiles at 1 A GeV have been measured with the FRagment Separator (FRS) at GSI. The measured cross sections are compared to {sup 238}U fission yields and model calculations to determine the optimum reaction mechanism to extend the limits of the chart of the nuclides around the r-process waiting point at N=82.

  5. Studies on the use of perchloroethylene as a heavy medium for the removal of pyrites from coal

    SciTech Connect

    Thome, T.L.; Fullerton, K.L.; Lee, S.

    1996-12-31

    Previous studies have shown that perchloroethylene (PCE) shows promise for use as a heavy medium for the removal of pyrites from fine coal. The studies are continued here, as the coal cleaning effectiveness of mixtures of PCE and kerosene are investigated. Float/sink experiments are run for different medium densities obtained by varying the proportions of PCE and kerosene. The effectiveness of the cleaning process is judged by data taken from a long tube sampling apparatus. Among the variables investigated are medium density, residence time, and solvent-to-coal ratio. The data is used to support scale-up predictions for a plant apparatus.

  6. Using Extractive FTIR to Measure N2O from Medium Heavy Duty Vehicles Powered with Diesel and Biodiesel Fuels

    EPA Science Inventory

    A Fourier Transform Infrared (FTIR) spectrometer was used to measure N2O and other pollutant gases during an evaluation of two medium heavy-duty diesel trucks equipped with a Diesel Particulate Filter (DPF). The emissions of these trucks were characterized under a variety of oper...

  7. 75 FR 33565 - Notice of Intent To Prepare an Environmental Impact Statement for New Medium- and Heavy-Duty Fuel...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-14

    ... Emission Standards and Corporate Average Fuel Economy Standards, Final Rule, 75 FR 25324 (May 7, 2010). In... Environmental Policy Act Regulations, 46 FR 18026 (1981) (emphasis added). NHTSA is also proposing to consider... Impact Statement for New Medium- and Heavy-Duty Fuel Efficiency Improvement Program AGENCY:...

  8. Photoactivation experiment on Au197 and its implications for the dipole strength in heavy nuclei

    NASA Astrophysics Data System (ADS)

    Nair, C.; Erhard, M.; Junghans, A. R.; Bemmerer, D.; Beyer, R.; Grosse, E.; Klug, J.; Kosev, K.; Rusev, G.; Schilling, K. D.; Schwengner, R.; Wagner, A.

    2008-11-01

    The 197Au(γ,n) reaction is used as an activation standard for photodisintegration studies on astrophysically relevant nuclei. At the bremsstrahlung facility of the superconducting electron accelerator ELBE (Electron Linear accelerator of high Brilliance and low Emittance) of Forschungszentrum Dresden-Rossendorf, photoactivation measurements on Au197 have been performed with bremsstrahlung endpoint energies from 8.0 to 15.5 MeV. The measured activation yield is compared with previous experiments as well as with calculations using Hauser-Feshbach statistical models. It is shown that the experimental data are best described by a two-Lorentzian parametrization with taking the axial deformation of Au197 into account. The experimental 197Au(γ,n) reaction yield measured at ELBE via the photoactivation method is found to be consistent with previous experimental data using photon scattering or neutron detection methods.

  9. Detection of the isotopes of heavy cosmic ray nuclei. [by particle counter telescope

    NASA Technical Reports Server (NTRS)

    Gilman, C. M.; Waddington, C. J.

    1975-01-01

    A counter telescope designed to detect and resolve the isotopic composition of cosmic ray nuclei heavier than neon is being prepared. The telescope consists of a rather conventional charge measuring array using two scintillator elements and two solid Cerenkov radiators of differing refractive index. The mass measurement is obtained by combining the velocity information from one or both of the Cerenkov radiators operating near their threshold with residual range measured in a block of nuclear emulsion. Path length corrections and particle location in the emulsions is provided by a spark chamber fired in coincidence with potentially suitable particles. The telescope has a geometry factor of 530 sq cm sr roughly. It should be able to resolve the isotopes of iron over the energy range of 300 to 720 Mev/n and those of neon over 300 to 400 MeV/n. The expected response and characteristics of the telescope are described in detail and the sensitivity to rare isotopes discussed.

  10. The Energetic Trans-Iron Composition Experiment (ENTICE) on the Heavy Nuclei Explorer (HNX) Mission

    NASA Technical Reports Server (NTRS)

    Israel, M. H.; Adams, James H., Jr.; Barbier, L. M.; Binns, W. R.; Christian, E. R.; Craig, N.; Cummings, A. C.; Doke, T.; Hasebe, N.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    The ENTICE experiment is one of two instruments that make up the HNX mission. The experimental goal of ENTICE is to measure with high precision the elemental abundances of all nuclei with Z between 10 and 82. This will enable us to determine if the injection mechanism for the cosmic ray accelerator is controlled by FIP or Volatility and to study the mix of nucleosynthetic processes that contribute to the galactic cosmic ray source. The ENTICE experiment utilizes the dE/dx-C method of charge determination and consists of silicon dE/dx detectors, Cherenkov detectors with two different refractive indices, and a fiber hodoscope. We will describe the instrument and its performance based on beam tests of a prototype instrument.

  11. Heavy metal contamination of road-deposited sediments in a medium size city of China.

    PubMed

    Zhu, Wei; Bian, Bo; Li, Lei

    2008-12-01

    Road-deposited sediment (RDS) is an important environmental medium that affects the characteristics of heavy metals in stormwater runoff. 62 RDS samples were collected from four different land use types (commercial, residential, intense traffic and riverside park) in the Zhenjiang city of China. The samples were analysed for concentrations of five metals (Zn, Pb, Cu, Cr and Ni). The maximum mean concentrations of Zn, Pb, Cu, Cr and Ni from different land use types were 686, 589, 158, 129 and 125 mg/kg, respectively. The intense traffic area displayed the highest metal concentrations, whilst Zn, Cr, Ni and Cu did not show any discernible variations among the other three areas. Seven particle sizes were analysed separately for the heavy metal concentrations. In all studied areas, particles <63 microm have the highest metal concentrations: 926-1,188 mg/kg of Zn, 270-928 mg/kg of Pb, 150-220 mg/kg of Cu, 99-172 mg/kg of Cr and 96-147 mg/kg of Ni. The fine particle fraction (<63 microm) of the samples accounted for about 25-60% of the total metal loading; in contrast, the coarsest fraction (1,000-2,000 microm) only contributed 1-5%. The calculated ecological risk index shows that considerably high potential risks exist in the intense traffic area particularly due to high concentrations of Pb. These findings provide invaluable information for the development of appropriate management strategies to decrease nonpoint source contamination loading to the water environment in urban areas. PMID:18085420

  12. The feasibility of recovering medium to heavy oil using geopressured-geothermal fluids

    SciTech Connect

    Nequs-De Wys, J.; Plum, M.M. ); Kimmell, C.E. ); Hart, G.F. )

    1991-08-01

    Thermal enhanced oil recovery using geopressured-geothermal (GPGT) fluids is a unique concept for recovering heavy and medium oils that are bypassed during conventional production processes. The successful implementation of this technology would provide an environmentally clean and less expensive method of thermal recovery as opposed to the burning of crude oil or natural gas used widely by industry at the present time. GPGT fluids are under high pressure in their parent reservoir and, when linked to shallow reservoirs by suitable plumbing, will provide a self-propelled method of heat transfer to a target reservoir existing at shallow depth. GPGT fluids will heat the reservoir as in conventional thermal enhanced oil recovery. This will reduce the residual oil saturation and lower the viscosity of the oil so that it can be moved more easily and in greater amounts. The method is similar to hot water flooding, and thus the basic technology already exists. Alworth field of the south Texas Mirando trend is proposed as a pilot site. The temperatures of the upper Wilcox GPGT fluids in this region range form 350 to 500F, and salinities in the range of 3600 to 70,000 mg/L. The pressures are from 800 to 3500 psia flowing well-head pressure. The target reservoirs for injection of the GPGT fluids are the upper Eocene Jackson and Yegua sandstones. These reservoirs contain an estimated four million bbl of heavy oil in place (18 API) of which at least one million bbl could be recovered by thermal enhanced oil recovery. An additional 1.5 billion bbl of oil is recoverable from the 87 fields within the Mirando trend. Run of the economic model on the Alworth field suggests that it will be economic.

  13. Calculated half-lives and kinetic energies for spontaneous emission of heavy ions from nuclei

    SciTech Connect

    Poenaru, D.N.; Greiner, W.; Depta, K.; Ivascu, M.; Mazilu, D.; Sandulescu, A.

    1986-05-01

    The most probable decays by spontaneous emission of heavy ions are listed for nuclides with Z = 47--106 and total half-lives>1 ..mu..sec. Partial half-lives, branching ratios relative to ..cap alpha.. decay, kinetic energies, and Q values are estimated by using the analytical superasymmetric fission model, a semiempirical formula for those ..cap alpha..-decay lifetimes which have not been measured, and the new Wapstra--Audi mass tables. Numerous ''stable'' nuclides with Z>40 are found to be metastable with respect to the new decay modes. The current experimental status is briefly reviewed.

  14. Nucleon and heavy-ion total and absorption cross section for selected nuclei

    NASA Technical Reports Server (NTRS)

    Wilson, J. W.; Costner, C. M.

    1975-01-01

    Approximate solutions of the coupled-channel equations for high-energy composite particle scattering are obtained and are applied to the nuclear scattering problem. Relationships between several approximation procedures are established and discussed. The eikonal formalism is used with a small-angle approximation to calculate the coherent elastic scattered amplitude from which total and absorption cross sections are derived. Detailed comparisons with nucleon-nucleus experiments show agreement within 5 percent except at lower energies where the eikonal approximation is of questionable accuracy. Even at these lower energies, agreement is within 15 percent. Tables of cross sections required for cosmic heavy-ion transport and shielding studies are presented.

  15. Hypertriton and light nuclei production at Λ-production subthreshold energy in heavy-ion collisions

    NASA Astrophysics Data System (ADS)

    Zhang, Song; Chen, Jin-Hui; Ma, Yu-Gang; Xu, Zhang-Bu; Cai, Xiang-Zhou; Ma, Guo-Liang; Zhong, Chen

    2011-08-01

    High-energy heavy-ion collisions produce abundant hyperons and nucleons. A dynamical coalescence model coupled with the ART model is employed to study the production probabilities of light clusters, deuteron (d), triton (t), helion (3He), and hypertriton (3ΛH) at subthreshold energy of Aproduction (≈ 1 GeV per nucleon). We study the dependence on the reaction system size of the coalescence penalty factor per additional nucleon and entropy per nucleon. The Strangeness Population Factor shows an extra suppression of hypertriton comparing to light clusters of the same mass number. This model predicts a hypertriton production cross-section of a few μb in 36Ar+36Ar, 40Ca+40Ca and 56Ni+56Ni in 1 A GeV reactions. The production rate is as high as a few hypertritons per million collisions, which shows that the fixed-target heavy-ion collisions at CSR (Lanzhou/China) at Λ subthreshold energy are suitable for breaking new ground in hypernuclear physics.

  16. Hypertriton and light nuclei production at Lambda-production subthreshold energy in heavy-ion collisions

    SciTech Connect

    Zhang, S.; Zu, Z.; Chen, J.H., Ma, Y.G., Cai, X-Z, Ma, G.L., Zhong, C.

    2011-08-01

    High-energy heavy-ion collisions produce abundant hyperons and nucleons. A dynamical coalescence model coupled with the ART model is employed to study the production probabilities of light clusters, deuteron (d), triton (t), helion ({sup 3}He), and hypertriton ({sub {Lambda}}{sup 3}H) at subthreshold energy of Aproduction ({approx} 1 GeV per nucleon). We study the dependence on the reaction system size of the coalescence penalty factor per additional nucleon and entropy per nucleon. The Strangeness Population Factor (S{sub 3} = {sup 3}{sub {Lambda}}H/({sup 3}He x {Lambda}/p)) shows an extra suppression of hypertriton comparing to light clusters of the same mass number. This model predicts a hypertriton production cross-section of a few {mu}b in {sup 36}Ar+{sup 36}Ar, {sup 40}Ca+{sup 40}Ca and {sup 56}Ni+{sup 56}Ni in 1 A GeV reactions. The production rate is as high as a few hypertritons per million collisions, which shows that the fixed-target heavy-ion collisions at CSR (Lanzhou/China) at {Lambda} subthreshold energy are suitable for breaking new ground in hypernuclear physics.

  17. Evaluation of fuel consumption potential of medium and heavy duty vehicles through modeling and simulation.

    SciTech Connect

    Delorme, A.; Karbowski, D.; Sharer, P.; Energy Systems

    2010-03-31

    The main objective of this report is to provide quantitative data to support the Committee in its task of establishing a report to support rulemaking on medium- and heavy-duty fuel efficiency improvement. In particular, it is of paramount importance for the Committee to base or illustrate their conclusions on established models and actual state-of-the art data. The simulations studies presented in the report have been defined and requested by the members of the National Academy committee to provide quantitative inputs to support their recommendations. As such, various technologies and usage scenarios were considered for several applications. One of the objective is to provide the results along with their associated assumptions (both vehicle and drive cycles), information generally missing from public discussions on literature search. Finally, the advantages and limitations of using simulation will be summarized. The study addresses several of the committee tasks, including: (1) Discussion of the implication of metric selection; (2) Assessing the impact of existing technologies on fuel consumption through energy balance analysis (both steady-state and standard cycles) as well as real world drive cycles; and (3) Impact of future technologies, both individually and collectively.

  18. Photofission of Heavy Nuclei from 0.2 to 3.8 GeV

    SciTech Connect

    C. Cetina; P. Heimberg; B. L. Berman; W. J. Briscoe; G. Feldman; L. Y. Murphy; Hall Crannell; A. Longhi; D. I. Sober; J. C. Sanabria; G. Ya. Kezerashvili

    2002-04-01

    Total photofission cross sections for {sup 237}Np, {sup 233}U, {sup 235}U, {sup 238}U, {sup 232}Th, and {sup nat}Pb have been measured simultaneously, using tagged photons in the energy range E{sub {gamma}} = 0.17-3.84 GeV in Hall B at Jefferson Lab. The fission fragments were detected using parallel-plate avalanche detectors. Our results show that, of these nuclei, {sup 237}Np has the largest photofission cross section per nucleon, and that the photofission cross section for {sup 238}U relative to that for {sup 237}Np is about 80% over the entire energy range. The relative photofission cross sections per nucleon increase with the fissility parameter Z{sup 2}/A, approaching an apparent asymptote at the Z{sup 2}/A value for {sup 237}Np, and they do not depend strongly on the incident photon energy over this entire energy range. These results, together with a comparison of the {sup 237}Np photofission cross section per nucleon with total photoabsorption data, indicate that the photofission probability for {sup 237}Np is almost unity. If we make this assumption, we observe a significant shadowing of the interior nucleons starting below 1.5 GeV, so that the photoabsorption cross section decreases by 20% near 4 GeV.

  19. The Boson Expansion Theory as the Nuclear Structure Theory for the Heavy Nuclei.

    NASA Astrophysics Data System (ADS)

    Kim, Hyoung-Bae

    1987-09-01

    Sometime ago, Kishimoto and Tamura developed a formalism of boson expansion theory (BET), and then Weeks and Tamura showed that it fitted many experimental data of collective nuclei. This formalism has recently been simplified significantly by Pedrocchi, Jamaluddin and Tamura. The new and old theories are very closely related but are not exactly the same. It has thus been desired to see whether the new theory can also fit data, and to show that it indeed works well constitutes a major part of this thesis. It is in fact seen that a number of data of Sm, Os and Pt isotopes are explained nicely. Since the new form of the theory is rather simple, it permits us to take into account easily the effects of noncollective states to the behavior of collective states. This thesis shows that a remarkably improved fit to data of magnetic moments of Sm isotopes is achieved in this way. The thesis discusses one additional subject. It is a result of an effort made to improve the BET by removing as much as possible the error due to the use of the BCS theory. This was done by applying a method developed by Li to the Dyson form of BET. A way to develop this work further is suggested.

  20. The boson expansion theory as the nuclear structure theory for the heavy nuclei

    SciTech Connect

    Kim, H.B.

    1987-01-01

    Sometime sago, Kishimoto and Tamura developed a formalism of boson expansion theory (BET), and then Weeks and Tamura showed that it fitted many experimental data of collective nuclei. This formalism has recently been simplified significantly be Pedrocchi, Jamaluddin and Tamura. The new and old theories are very closely related but are not exactly the same. It has thus been desired to see whether the new theory can also fit data, and to show that it indeed works well constitutes a major part of this thesis. It is in fact seen that a number of data of Sm, Os and Pt isotopes are explained nicely. Since the new form of the theory is rather simple, it permits us to take into account easily the effects of noncollective states to the behavior of collective states. This thesis shows that are remarkably improved fit to data of magnetic moments of SM isotopes is achieved in this way. The thesis discusses one additional subject. It is a result of an effort made to improve the BET by removing as much as possible the error due to the use of the BCS theory. This was done by applying a method developed by Li to the Dyson form of BET. A way to develop this work further is suggested.

  1. LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray F04

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray F04 EL-1994-00171 LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray F04 The postflight photograph was taken in the SAEF II at KSC after the experiment was removed from the LDEF. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays lower flange is a copper coated pressure sensitive tape used to provide an electrical ground between the experiments thermal cover and the LDEF structure. The UHCRE thermal cover appears to be specular and intact. The circular damaged locations that appeared to to be impact points in the flight photograph are not as apparent in the reflections and is less taut cover. The wrinkled spots on the thermal cover are areas

  2. Status and prospects of investigations into the collinear cluster decay of heavy nuclei

    SciTech Connect

    Pyatkov, Yu. V.; Kamanin, D. V.; Alexandrov, A. A.; Alexandrova, I. A.; Mkaza, N.; Zhuchko, V. E.; Kondratyev, N. A.; Kuznetsova, E. A. Mishinsky, G. V.; Malaza, V.; Strekalovsky, A. O.; Strekalovsky, O. V.

    2014-12-15

    Basic experimental results confirming the existence a new cluster-decay type called collinear cluster tripartition (CCT) are presented. Decays of this type manifest themselves, in particular, as a two-dimensional region of a locally enhanced yield of fragments (bump) that corresponds to specific missing-mass values in the mass-mass distribution of fission fragments. One of the decay modes that contribute to the bump can be treated as a cluster-decay type that is new in relation to the well-known heavy-ion or lead radioactivity. The conclusions drawn from an analysis of correlation mass distributions are confirmed by the results obtained from neutron-gated data, measurements of the nuclear charge for CCT events, and the direct detection of new-decay products.

  3. Status and prospects of investigations into the collinear cluster decay of heavy nuclei

    NASA Astrophysics Data System (ADS)

    Pyatkov, Yu. V.; Kamanin, D. V.; Alexandrov, A. A.; Alexandrova, I. A.; Mkaza, N.; Zhuchko, V. E.; Kondratyev, N. A.; Kuznetsova, E. A.; Mishinsky, G. V.; Malaza, V.; Strekalovsky, A. O.; Strekalovsky, O. V.

    2014-12-01

    Basic experimental results confirming the existence a new cluster-decay type called collinear cluster tripartition (CCT) are presented. Decays of this type manifest themselves, in particular, as a two-dimensional region of a locally enhanced yield of fragments (bump) that corresponds to specific missing-mass values in the mass-mass distribution of fission fragments. One of the decay modes that contribute to the bump can be treated as a cluster-decay type that is new in relation to the well-known heavy-ion or lead radioactivity. The conclusions drawn from an analysis of correlation mass distributions are confirmed by the results obtained from neutron-gated data, measurements of the nuclear charge for CCT events, and the direct detection of new-decay products.

  4. The Electron Shell and Alpha Decay in Super-Heavy Nuclei

    NASA Astrophysics Data System (ADS)

    Igashov, S. Yu.; Tchuvil'Sky, Yu. M.

    2015-11-01

    The influence of the electron shell on the characteristics of the alpha decay of the 294118 isotope, as an example of a super-heavy atom, is studied theoretically. The calculation is based on direct solution of the Schrödinger equation. The rigorous quantum-mechanical approach being developed makes possible the outer boundary condition of the alpha-particle diverging wave to be taken into account properly. The effect under discussion depends on the behavior of the function of electron density both in the classically-forbidden and the classically-allowed areas of alpha-particle motion. A principally new effect - increasing of the decay rate originated by the part of electron shell located in the classically-allowed area - is revealed in the chosen example. The influence of relativistic properties of inner electrons, scenario of penetration of the alpha-particle through the atomic shell and finite size of nucleus are also studied.

  5. LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray B07

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray B07 EL-1994-00312 LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray B07 The postflight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken in SAEF II at KSC after removal of the experiment tray from the LDEF. The outline of the experiment tray clamp blocks is clearly visible on the upper tray flange and to a lesser extent on the lower flange. The holding fixture hardware covers the clamp block areas on the end flanges. The prelaunch photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken in SAEF II at KSC prior to installation of the experiment tray on the LDEF. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the

  6. Nucleon-induced fission cross sections of heavy nuclei in the intermediate energy region

    NASA Astrophysics Data System (ADS)

    Prokofiev, Alexander V.

    Fission is the most important nuclear reaction for society at large today due to its use in energy production. However, this has raised the problem of how to treat the long-lived radioactive waste from nuclear reactors. A radical solution would be to change the composition of the waste into stable or short-lived nuclides, which could be done through nuclear transmutation. Such a concept requires accelerator-driven systems to be designed, where those for transmutation are reactor hybrids. This thesis is a contribution to the knowledge base for developing transmutation systems, specifically with respect to the computational modeling of the underlying nuclear reactions, induced by the incident and secondary particles. Intermediate energy fission cross sections are one important type of such data. Moreover, they are essential for understanding the fission process itself and related nuclear interactions. The experimental part of this work was performed at the neutron beam facility of The Svedberg Laboratory in Uppsala. Fission cross sections of 238U, 209Bi, natPb, 208Pb, 197Au, natW, and 181Ta were measured for neutrons in the range En = 30-160 MeV using thin-film breakdown counters for the fission fragment detection. A model was developed for the determination of the efficiency of such detectors. A compilation of existing data on proton-induced fission cross sections for nuclei from 165Ho to 239Pu was performed. The results, which constitute the main body of information in this field, were added to the worldwide EXFOR database. The dependences of the cross sections on incident energy and target nucleus were studied, which resulted in systematics that make it possible to give estimates for unmeasured nuclides. Nucleon-induced fission cross sections were calculated using an extended version of the cascade exciton model. A comparison with the systematics and the experimental data obtained in the present work revealed significant discrepancies. A modification of the model

  7. LOW-FIDELITY COVARIANCES FOR NEUTRON CROSS SECTIONS ON 57 STRUCTURAL AND 31 HEAVY NUCLEI IN THE FAST REGION.

    SciTech Connect

    PIGNI,M.T.; HERMAN, M.; OBLOZINSKY, P.

    2008-03-01

    We produced a large set of neutron cross section covariances in the energy range of 5 keV-20 MeV. The present set of data on 57 structural materials and 31 heavy nuclei follows our earlier work on 219 fission product materials and completes our extensive contribution to the low-fidelity covariance project (307 materials). This project aims to provide initial, low-fidelity yet consistent estimates of covariance data for nuclear criticality safety applications. The evaluation methodology combines the nuclear reaction model code EMPIRE which calculates sensitivity to nuclear reaction model parameters, and the Bayesian code KALMAN that propagates uncertainties of the model parameters to cross sections. Taking into account the large scale of the project, only marginal reference to experimental data was made. The covariances were derived from the perturbation of several key model parameters selected by the sensitivity analysis. These parameters refer to the optical model potential, the level densities and the strength of the pre-equilibrium emission. This work represents the first attempt ever to generate nuclear data covariances on such a large scale.

  8. Band-head spectra of low-energy single-particle excitations in some well-deformed, odd-mass heavy nuclei within a microscopic approach

    NASA Astrophysics Data System (ADS)

    Koh, Meng-Hock; Duy Duc, Dao; Nhan Hao, T. V.; Thuy Long, Ha; Quentin, P.; Bonneau, L.

    2016-01-01

    In four well-deformed heavy odd nuclei, the energies of low-lying rotational band heads have been determined microscopically within a self-consistent Hartree-Fock-plus-BCS approach with blocking. A Skyrme nucleon-nucleon effective interaction has been used together with a seniority force to describe pairing correlations. Only such states which are phenomenologically deemed to be related to single-particle excitations have been considered. The polarization effects, including those associated with the genuine time-reversal symmetry breaking have been fully taken into account within our model assumptions. The calculated spectra are in reasonably good qualitative agreement with available data for the considered odd-neutron nuclei. This is not so much the case for the odd-proton nuclei. A potential explanation for such a difference in behavior is proposed.

  9. Effect of three-body Coulomb interactions on the breakup of light nuclei in the field of a heavy ion: An asymptotic estimate

    SciTech Connect

    Alt, E.O.; Irgaziev, B.F.; Muminov, A.T.

    1995-11-01

    The quasielastic breakup of light nuclei into two charged fragments in the Coulomb field of a heavy multiply charged ion are studied. For fragments diverging with extremely low energies an asymptotic estimate is obtained for the ratio of the differential cross section in which three-body Coulomb effects are taken into account to that in which these effects are disregarded. It is shown that effects due to the acceleration of breakup fragments in the field of the heavy ion are significant. 13 refs., 2 figs.

  10. Physics of Unstable Nuclei

    NASA Astrophysics Data System (ADS)

    Khoa, Dao Tien; Egelhof, Peter; Gales, Sydney; Giai, Nguyen Van; Motobayashi, Tohru

    2008-04-01

    . -- Thermal pairing in nuclei / N. D. Dang -- Molecular-orbital and di-nuclei states in Ne and F isotopes / M. Kimura -- Low-momentum interactions for nuclei / A. Schwenk -- Nonrelativistic nuclear energy functionals including the tensor force / G. Colo et al. -- New aspects on dynamics in nuclei described by covariant density functional theory / P. Ring, D. Pena -- Theoretical studies on ground-state properties of superheavy nuclei / Z. Z. Ren et al. -- New results in the study of superfluid nuclei: many-body effects, spectroscopic factors / P. F. Bortignon et al. -- New Effective nucleon-nucleon interaction for the mean-field approximation / V. K. Au et al. -- Linear response calculations with the time-dependent Skyrme density functional / T. Nakatsukasa et al. -- Dissipative dynamics with exotic beams / M. Di Toro et al. -- Exploring the symmetry energy of asymmetric nuclear matter with heavy ion reactions / M. B. Tsang -- Invariant mass spectroscopy of halo nuclei / T. Nakamura et al. -- Core [symbol] structures in [symbol]C, [symbol]C and [symbol]C up to high excitation energies / H. G. Bohlen et al. -- Light neutron-rich nuclei studied by alpha-induced reactions / S. Shimoura -- Fusion and direct reactions around the Coulomb barrier for the system [symbol]He + [symbol]Zn / V. Scuderi et al. -- Analyzing power measurement for proton elastic scattering on [symbol]He / S. Sakaguchi et al. -- Knockout reaction spectroscopy of exotic nuclei / J. A. Tostevin -- Exotic nuclei, quantum phase transitions, and the evolution of structure / R. F. Casten -- Structure of exotic nuclei in the medium mass region / T. Otsuka -- Pairing correlations in halo nuclei / H. Sagawa, K. Hagino -- Experimental approach to high-temperature Stellar reactions with low-energy RI beams / S. Kubono et al. -- Transition to quark matter in neutron stars / G. X. Peng et al. -- Research at VATLY: main themes and recent results / P. N. Diep et al. -- Study of the astrophysical reaction [symbol