Science.gov

Sample records for heavy odd-mass nuclides

  1. Microscopic description of ground state magnetic moment and low-lying magnetic dipole excitations in heavy odd-mass 181Ta nucleus

    NASA Astrophysics Data System (ADS)

    Tabar, Emre; Yakut, Hakan; Kuliev, Ali Akbar

    2016-07-01

    The ground state magnetic moments and the low-lying magnetic dipole (Ml) transitions from the ground to excited states in heavy deformed odd-mass 181Ta have been microscopically investigated on the basis of the quasiparticle-phonon nuclear model (QPNM). The problem of the spurious state mixing in M1 excitations is overcome by a restoration method allowing a self-consistent determination of the separable effective restoration forces. Due to the self-consistency of the method, these effective forces contain no arbitrary parameters. The results of calculations are compared with the available experimental data, the agreement being reasonably satisfactory.

  2. Identification of Heavy and Superheavy Nuclides Using Chemical Separator Systems

    SciTech Connect

    Turler, Andreas

    1999-12-31

    With the recent synthesis of superheavy nuclides produced in the reactions {sup 48}Ca+{sup 238}U and {sup 48}Ca+{sup 242,244}Pu, much longer-lived nuclei than the previously known neutron-deficient isotopes of the heaviest elements have been identified. Half-lives of several hours and up to several years have been predicted for the longest-lived isotopes of these elements. Thus, the sensitivity of radiochemical separation techniques may present a viable alternative to physical separator systems for the discovery of some of the predicted longer-lived heavy and superheavy nuclides. The advantages of chemical separator systems in comparison to kinematic separators lie in the possibility of using thick targets, high beam intensities spread over larger target areas and in providing access to nuclides emitted under large angles and low velocities. Thus, chemical separator systems are ideally suited to study also transfer and (HI, axn) reaction products. In the following, a study of (HI, axn) reactions will be presented and prospects to chemically identify heavy and superheavy elements discussed.

  3. Effective field theory for vibrations in odd-mass nuclei

    NASA Astrophysics Data System (ADS)

    Coello Pérez, E. A.; Papenbrock, T.

    2016-11-01

    Heavy even-even nuclei exhibit low-energy collective excitations that are separated in scale from the microscopic (fermion) degrees of freedom. This separation of scale allows us to approach nuclear vibrations within an effective field theory (EFT). In odd-mass nuclei collective and single-particle properties compete at low energies, and this makes their description more challenging. In this article we describe spherical odd-mass nuclei with ground-state spin I =1/2 by means of an EFT that couples a fermion to the collective degrees of freedom of an even-even core. The EFT relates observables such as energy levels, electric quadrupole transition strengths, and magnetic dipole moments of the odd-mass nucleus to those of its even-even neighbor and allows us to quantify theoretical uncertainties. For isotopes of rhodium and silver the theoretical description is consistent with data within experimental and theoretical uncertainties. Several testable predictions are made.

  4. Heavy mass elements total half-lives for selected long-lived nuclides

    SciTech Connect

    Holden, N.E.

    1985-01-01

    In the past, many compilations and evaluations of half-lives have been made which have uncritically accepted authors' values and uncertainties. They have merely recommended weight-averaged reported results. This evaluation attempts to reanalyze each experiment in the literature including an estimate of the standard deviation utilizing, where possible, an estimate of the systematic error. This paper constitutes a preliminary step in the process of recommending values. The long-lived nuclides of heavy mass elements are of interest in determining geological ages using the Re-Os or the Lu-Hf dating methods, in supplying information on the p-process (proton capture) of nucleo-synthesis, in providing information on lepton number conservation and the rest mass for the electron neutrino from double ..beta.. decay processes and in the case of tantalum because it represents the first long-lived state which is actually an isomer. Experimental data on the half-lives of selected nuclides have been evaluated and recommended values and uncertainties are presented for the following nuclides: /sup 128/Te, /sup 130/Te, /sup 129/I, /sup 138/La, /sup 144,145/Nd, /sup 146,147,148/Sm, /sup 152/Gd, /sup 154/Dy, /sup 176/Lu, /sup 174/Hf, /sup 180/Ta, /sup 187/Re, /sup 186/Os, /sup 190/Pt, /sup 204,205/Pb and /sup 230,232/Th. It is shown that /sup 204/Pb, which was previously thought to be radioactive, is stable. For /sup 205/Pb, the L electron capture x-rays have been revised for the M and higher x-ray yields. The resulting half-life for /sup 205/Pb is 1.9 +- 0.3 x 10/sup 7/ years. /sup 146/Sm with a half-life of 1.03 +- 0.05 x 10/sup 8/ years is the longest-lived extinct natural nuclide. 21 tabs.

  5. Influence of heavy natural radioactive nuclides introduced in soil with labelled fertilizers and ameliorants on cytogenetic effects in plants

    SciTech Connect

    Arkhipov, N.P.; Bazylev, V.V.; Bobrikova, E.T.; Fevraleva, L.T.; Kal'chenko, VA.; Shevchenko, V.A.

    1985-05-01

    The effect of heavy natural radioactive nuclides (STYU, STSTh, SSWRa, S Po, and S Pb) in labeled fertilizers and ameliorants on the number of meiotic chromosome aberrations was studied in field experiments on the major crop plants, wheat, barley and corn. The mining and use of coal and oil and the processing of raw materials in the production of rare and nonferrous metals produce high quantities of wastes with an elevated content of natural radionuclides. One possible way for technogenically altering the natural radiation background of soil is the active utilization of phosphorus fertilizers in agriculture, and also the use, as fertilizers and ameliorants of wastes from nonferrous metallurgy, of the ash from heat and power plants and various intermediates from the chemical industry. The authors conclude that the introduction of labeled ammophos, nitrophos and phosphogypsum, which raised the soil background concentration of the specified elements, produced an increase in the number of cells with meiotic chromosome aberrations.

  6. Precision Mass Measurements of Short-Lived Nuclides at The Heavy-Ion Storage Ring in Lanzhou

    NASA Astrophysics Data System (ADS)

    Zhang, Yuhu; Xu, Hushan; Litvinov, Yuri A.

    Recent commissioning of the Cooler Storage Ring at the Heavy Ion Research Facility in Lanzhou enabled us to conduct high-precision mass measurements at the Institute of Modern Physics in Lanzhou (IMP). In the past few years, mass measurements were performed using the CSRe-based isochronous mass spectrometry employing the fragmentation of the energetic beams of 58Ni, 78Kr, 86Kr, and 112Sn projectiles. Masses of short-lived nuclides of on both sides of the stability valley were addressed. Relative mass precision of down to 10-6-10-7 is routinely achieved. The mass values were used as an input for dedicated nuclear structure and astrophysics studies, providing for instance new insights into the rp-process of nucleosynthesis in X-ray bursts. In this contribution, we briefly review the so far conducted experiments and the main achieved results, as well as outline the plans for future experiments.

  7. Silicon multistrip detectors and caesium iodide scintillator for identification of heavy and ultra heavy nuclides in space experiments

    NASA Astrophysics Data System (ADS)

    Miozza, Maurizio

    1997-03-01

    An instrument made of silicon multistrip detectors, time-of-flight and caesium iodide scintillators for ion identification in cosmic ray experiments has been constructed and tested. The charge dynamic of the preamplifier reading the silicon multistrip detectors allows to identify all the nuclides of the periodic table. A redundant method for measuring the ion energy, autotrigger capability and low power consumption of the silicon detector readout are the major characteristic features of the apparatus. Performance results of the instrument, tested with a calcium beam of 0.5 GeV/u at the GSI accelerator, are presented.

  8. Optical model methods of predicting nuclide production cross sections from heavy ion fragmentation

    NASA Technical Reports Server (NTRS)

    Townsend, L. W.; Ramsey, C. R.; Tripathi, R. K.; Cucinotta, F. A.; Norbury, J. W.; Wilson, J. W. (Principal Investigator)

    1999-01-01

    Quantum mechanical optical potential methods for calculating inclusive isotope and element production cross sections from the fragmenting of heavy nuclei by intermediate- and high-energy protons and heavy ions are presented based upon a modified abrasion-ablation-FSI (frictional spectator interaction) collision model. The abrasion stage is treated as a quantum mechanical knockout process that leaves the residual prefragment in an excited state. Prefragment excitation energies are estimated using a combined liquid drop and FSI method. In ablation the prefragment deexcites by particle and photon emission to produce the final fragment. Contributions from electromagnetic dissociation to single nucleon removal cross sections are incorporated using a Weiszacker-Williams theory that includes electric dipole and electric quadrupole interactions. Estimates of elemental and isotopic production cross sections are in good agreement with published cross section measurements for a variety of projectile-target-beam energy combinations.

  9. Neutron-proton pairing correlations in odd mass systems

    SciTech Connect

    Fellah, M. Allal, N. H.; Oudih, M. R.

    2015-03-30

    An expression of the ground-state which describes odd mass systems within the BCS approach in the isovector neutron-proton pairing case is proposed using the blocked level technique. The gap equations as well as the energy expression are then derived. It is shown that they exactly generalize the expressions obtained in the pairing between like-particles case. The various gap parameters and the energy are then numerically studied as a function of the pairing-strength within the schematic one-level model.

  10. Structure evolution and phase transition in odd-mass nuclei

    NASA Astrophysics Data System (ADS)

    Bucurescu, D.; Zamfir, N. V.

    2017-01-01

    The evolution of level structures due to the unique parity orbitals g9 /2, h11 /2, and i13 /2 in odd-mass nuclei from Zn to Am is studied within a unified framework, by correlations between ratios of excitation energies in both odd-mass nuclei and their even-even core nuclei. These plots reveal regularities that can be understood in terms of the particle-plus-rotor model, as evolutions along its three limiting coupling schemes: weak coupling, decoupling, and strong coupling, and transitions between them. Peculiar transitions between the decoupling and strong coupling schemes are found in both i13 /2 structures of neutron-odd nuclei and h11 /2 structures of proton-odd nuclei, at neutron numbers around 90 and 70, respectively. These are correlated with the critical shape phase transitions from vibrator to rotor from the even-even nuclei in the same regions and are characterized as critical phase transitions too. This behavior is corroborated with a nonmonotonic behavior of the differential variation of the two-neutron separation energies in the same nuclear regions.

  11. Signatures of shape phase transitions in odd-mass nuclei

    NASA Astrophysics Data System (ADS)

    Nomura, K.; Nikšić, T.; Vretenar, D.

    2016-12-01

    Quantum phase transitions between competing ground-state shapes of atomic nuclei with an odd number of protons or neutrons are investigated in a microscopic framework based on nuclear energy density functional theory and the particle-plus-boson-core coupling scheme. The boson-core Hamiltonian, as well as the single-particle energies and occupation probabilities of the unpaired nucleon, are completely determined by constrained self-consistent mean-field calculations for a specific choice of the energy density functional and paring interaction, and only the strength parameters of the particle-core coupling are adjusted to reproduce selected spectroscopic properties of the odd-mass system. We apply this method to odd-A Eu and Sm isotopes with neutron number N ≈90 , and explore the influence of the single unpaired fermion on the occurrence of a shape phase transition. Collective wave functions of low-energy states are used to compute quantities that can be related to quantum order parameters: deformations, excitation energies, E 2 transition rates, and separation energies, and their evolution with the control parameter (neutron number) is analyzed.

  12. Beyond mean-field calculations for odd-mass nuclei.

    PubMed

    Bally, B; Avez, B; Bender, M; Heenen, P-H

    2014-10-17

    Beyond mean-field methods are very successful tools for the description of large-amplitude collective motion for even-even atomic nuclei. The state-of-the-art framework of these methods consists in a generator coordinate method based on angular-momentum and particle-number projected triaxially deformed Hartree-Fock-Bogoliubov (HFB) states. The extension of this scheme to odd-mass nuclei is a long-standing challenge. We present for the first time such an extension, where the generator coordinate space is built from self-consistently blocked one-quasiparticle HFB states. One of the key points for this success is that the same Skyrme interaction is used for the mean-field and the pairing channels, thus avoiding problems related to the violation of the Pauli principle. An application to ^{25}Mg illustrates the power of our method, as agreement with experiment is obtained for the spectrum, electromagnetic moments, and transition strengths, for both positive and negative parity states and without the necessity for effective charges or effective moments. Although the effective interaction still requires improvement, our study opens the way to systematically describe odd-A nuclei throughout the nuclear chart.

  13. Alpha spectroscopy of nuclides produced in the interaction of 5 GeV protons with heavy element targets

    NASA Astrophysics Data System (ADS)

    Bowman, J. David; Eppley, Richard E.; Hyde, Earl K.

    1982-02-01

    Alpha particle energies were redetermined to an accuracy of 2 to 5 keV for a group of 40 neutron-deficient nuclides with atomic numbers ranging from 65 to 88. Improved half-life values were measured for 10 of these nuclides. Weightless samples containing mixtures of these activities were prepared by use of the helium jet transport technique to remove spallation and fragmentation products recoiling from targets of U, Th, Au, and Ta bombarded with 5 GeV protons. Experimental and calibration techniques are discussed in detail. Implications of the results for the mechanism of reaction of 5 GeV protons with complex targets are briefly discussed. RADIOACTIVITY 5 GeV p + U, Th, Au, Ta; separated recoil products by helium jet; measured Eα, t12 151Dy, 154Er, 150Dy, 152Ho, 152Hom, 151Ho, 151Hom, 153Er, 152Er, 154Tm, 154Tmm, 153Tm, 179Pt, 155Yb, 178Pt, 177Pt, 176Pt, 199Pom, 198Po, 212Fr, 197Pom, 213Fr, 212Ra; measured Eα 149Tb, 211At, 204Fr, 222Ac, 217At, 218Rn, 219Fr, 211Po, 214Po, 217Rn, 216At, 218Fr, 215At, 213Po, 212Po, 214At, 211Pom; reaction mechanisms discussed.

  14. Nuclides Economy

    SciTech Connect

    Ivanov, Evgeny; Subbotin, Stanislav

    2007-07-01

    Traditionally the subject of discussion about the nuclear technology development is focused on the conditions that facilitate the nuclear power deployment. The main objective of this work is seeking of methodological basis for analysis of the coupling consequences of nuclear development. Nuclide economy is the term, which defines a new kind of society relations, dependent on nuclear technology development. It is rather closed to the setting of problems then to the solving of them. Last year Dr. Jonathan Tennenbaum published in Executive Intelligence Review Vol. 33 no 40 the article entitled as 'The Isotope Economy' where main interconnections for nuclear energy technologies and their infrastructure had been explained on the popular level. There he has given several answers and, therefore, just here we will try to expand this concept. We were interested by this publication because of similarity of our vision of resource base of technologies development. The main paradigm of 'Isotope economy' was expresses by Lyndon H. LaRouche: 'Instead of viewing the relevant resources of the planet as if they were a fixed totality, we must now assume responsibility of man's creating the new resources which will be more than adequate to sustain a growing world population at a constantly improved standard of physical per-capita output, and personal consumption'. We also consider the needed resources as a dynamic category. Nuclide economy and nuclide logistics both are needed for identifying of the future development of nuclear power as far we follow the holistic analysis approach 'from cave to grave'. Thus here we try to reasoning of decision making procedures and factors required for it in frame of innovative proposals development and deployment. The nuclear power development is needed in humanitarian scientific support with maximally deep consideration of all inter-disciplinary aspects of the nuclear power and nuclear technologies implementation. The main objectives for such

  15. Experimental identification of intruder bandheads in odd-mass {sup 187-193}Pb

    SciTech Connect

    Andreyev, A. N.; Huyse, M.; Van de Vel, K.; Van Duppen, P.; Cocks, J. F. C.; Dorvaux, O.; Greenlees, P.; Jones, P.; Julin, R.; Juutinen, S.; Helariutta, K.; Kettunen, H.; Kuusiniemi, P.; Leino, M.; Muikku, M.; Trzaska, W. H.; Eskola, K.; Wyss, R.

    1999-11-16

    Fine-structure {alpha}-decays of the odd mass {sup 191-197}Po identifying proton based intruder states in the daughter lead nuclei have been observed, leading to a systematics of intruder states in odd mass lead isotopes from {sup 197}Pb down to {sup 187}Pb. The interpretation of these states involves the coupling of the i{sub 13/2} or p{sub 3/2} odd neutron to the oblate deformed even lead core.

  16. Experimental Identification of Intruder Bandheads in Odd-Mass {sup 187-193}Pb

    SciTech Connect

    A.N. Andreyev; J.F.C. Cocks; O. Dorvaux; K. Eskola; P. Greenlees; P. Jones; R. Julin; S. Juutinen; K. Helariutta; M. Huyse; H. Kettunen; P. Kuusiniemi; M. Leino; M. Muikku; W.H. Trzaska; K. Van de Vel; P. Van Duppen; R. Wyss

    1999-12-31

    Fine-structure {alpha}-decays of the odd mass {sup 191-197}Po identifying proton based intruder states in the daughter lead nuclei have been observed, leading to a systematics of intruder states in odd mass lead isotopes from {sup 197}Pb down to {sup 187}Pb. The interpretation of these states involves the coupling of the i{sub 13/2} or p{sub 3/2} odd neutron to the oblate deformed even lead core.

  17. Workshop on Cosmogenic Nuclides

    NASA Technical Reports Server (NTRS)

    Reedy, R. C. (Editor); Englert, P. (Editor)

    1986-01-01

    Abstracts of papers presented at the Workshop on Cosmogenic Nuclides are compiled. The major topic areas covered include: new techniques for measuring nuclides such as tandem accelerator and resonance mass spectrometry; solar modulation of cosmic rays; pre-irradiation histories of extraterrestrial materials; terrestrial studies; simulations and cross sections; nuclide production rate calculations; and meteoritic nuclides.

  18. Positive parity low spin states of odd-mass tellurium isotopes

    NASA Astrophysics Data System (ADS)

    Yazar, Harun Reşit

    2006-11-01

    In this work, we analyse the positive parity of states of odd-mass nucleus within the framework of interacting boson fermion model. The result of an IBFM-1 multilevel calculation with the lg 9/2, 2d 5/2, 2d 3/2, 3s 1/2 and one level, 1h 11/2 with negative parity, single particle orbits is reported for the positive parity states of the odd mass nucleus 123-125Te. Also, an IBM-1 calculation is presented for the low-lying states in the even-even 124-126Te core nucleus. The energy levels and B (E2) transition probabilities were calculated and compared with the experimental data. It was found that the calculated positive parity low spin state energy spectra of the odd-mass 123-125Te isotopes agree quite well with the experimental data.

  19. Theoretical study of band structure of odd-mass 115,117I isotopes

    NASA Astrophysics Data System (ADS)

    Singh, Dhanvir; Kumar, Amit; Sharma, Chetan; Singh, Suram; Bharti, Arun

    2016-05-01

    By using the microscopic approach of Projected Shell Model (PSM), negative-parity band structures of odd mass neutron-rich 115,117I nuclei have been studied with the deformed single-particle states generated by the standard Nilsson potential. For these isotopes, the band structures have been analyzed in terms of quasi-particles configurations. The phenomenon of back bending in moment of inertia is also studied in the present work.

  20. Theoretical study of band structure of odd-mass {sup 115,117}I isotopes

    SciTech Connect

    Singh, Dhanvir Kumar, Amit Sharma, Chetan; Singh, Suram; Bharti, Arun

    2016-05-06

    By using the microscopic approach of Projected Shell Model (PSM), negative-parity band structures of odd mass neutron-rich {sup 115,117}I nuclei have been studied with the deformed single-particle states generated by the standard Nilsson potential. For these isotopes, the band structures have been analyzed in terms of quasi-particles configurations. The phenomenon of back bending in moment of inertia is also studied in the present work.

  1. Study of nuclear structure of odd mass 119-127I nuclei in a phenomenological approach

    NASA Astrophysics Data System (ADS)

    Singh, Dhanvir; Gupta, Anuradha; Kumar, Amit; Sharma, Chetan; Singh, Suram; Bharti, Arun; Khosa, S. K.; Bhat, G. H.; Sheikh, J. A.

    2016-08-01

    By using the phenomenological approach of Projected Shell Model (PSM), the positive and negative-parity band structures of odd mass neutron-rich 119-127I nuclei have been studied with the deformed single-particle states generated by the standard Nilsson potential. For these isotopes, the band structures have been analyzed in terms of quasi-particles configurations. The phenomenon of backbending in moment of inertia is also studied in the present work. Besides this, the reduced transition probabilities, i.e. B (E 2) and B (M 1), are obtained from the PSM wavefunction for the first time for yrast bands of these isotopes.

  2. Microscopic description of low-lying M1 excitations in odd-mass actinide nuclei

    NASA Astrophysics Data System (ADS)

    Tabar, Emre; Yakut, Hakan; Kuliev, Ali Akbar

    2017-01-01

    A restoration method of a broken symmetry which allows self-consistent determination of the separable effective restoration forces is now adapted to odd-mass nuclei in order to restore violated rotational invariance (RI-) of the Quasiparticle Phonon Nuclear Model (QPNM) Hamiltonian. Because of the self-consistency of the method, these effective forces contain no arbitrary parameters. Within RI-QPNM, the properties of the low-lying magnetic dipole excitations in odd-mass deformed 229-233Th and 233-239U nuclei have been investigated for the first time. It has been shown that computed fragmentation of the M1 strengths below 4 MeV in these nuclei is much stronger than that in neighboring doubly even 228-232Th and 232-238U nuclei. For 235U the summed M1 strength in the energy range 1.5-2.8 MeV is in agreement with the relevant experimental data where the missing strength was extracted by means of a fluctuation analysis.

  3. Systematics of fine structure in the α decay of deformed odd-mass nuclei

    NASA Astrophysics Data System (ADS)

    Ren, Zhongzhou; Ni, Dongdong

    2014-12-01

    We present a detailed analysis of the a-decay fine structure in 32 deformed odd-mass nuclei from Z = 93 to Z = 102. The α-decay half-lives are systematically calculated within the multichannel cluster model (MCCM), which turns out to well reproduce the experimental data and show the neutron deformed shell structure. The branching ratios for various daughter states are investigated in the MCCM and in the WKB barrier penetration approach, respectively. It is found that the MCCM results agree well with the experimental data, while the WKB results have relatively large deviations from the experimental data for the α transitions to the high-lying members of the rotational band.

  4. Shape-phase transitions in odd-mass γ -soft nuclei with mass A ≈130

    NASA Astrophysics Data System (ADS)

    Nomura, K.; Nikšić, T.; Vretenar, D.

    2017-07-01

    Quantum phase transitions between competing equilibrium shapes of nuclei with an odd number of nucleons are explored using a microscopic framework of nuclear energy density functionals and a fermion-boson coupling model. The boson Hamiltonian for the even-even core nucleus, as well as the spherical single-particle energies and occupation probabilities of unpaired nucleons, are completely determined by a constrained self-consistent mean-field calculation for a specific choice of the energy density functional and pairing interaction. Only the strength parameters of the particle-core coupling have to be adjusted to reproduce a few empirical low-energy spectroscopic properties of the corresponding odd-mass system. The model is applied to the odd-A Ba, Xe, La, and Cs isotopes with mass A ≈130 , for which the corresponding even-even Ba and Xe nuclei present a typical case of γ -soft nuclear potential. The theoretical results reproduce the experimental low-energy excitation spectra and electromagnetic properties, and confirm that a phase transition between nearly spherical and γ -soft nuclear shapes occurs also in the odd-A systems.

  5. Particle-number conservation in odd mass proton-rich nuclei in the isovector pairing case

    NASA Astrophysics Data System (ADS)

    Fellah, M.; Allal, N. H.; Oudih, M. R.

    2015-06-01

    An expression of a wave function which describes odd-even systems in the isovector pairing case is proposed within the BCS approach. It is shown that it correctly generalizes the one used in the pairing between like-particles case. It is then projected on the good proton and neutron numbers using the Sharp-BCS (SBCS) method. The expressions of the expectation values of the particle-number operator and its square, as well as the energy, are deduced in both approaches. The formalism is applied to study the isovector pairing effect and the number projection one on the ground state energy of odd mass N ≈ Z nuclei using the single-particle energies of a deformed Woods-Saxon mean-field. It is shown that both effects on energy do not exceed 2%, however, the absolute deviations may reach several MeV. Moreover, the np pairing effect rapidly diminishes as a function of (N - Z). The deformation effect is also studied. It is shown that the np pairing effect, either before or after the projection, as well as the projection effect, when including or not the isovector pairing, depends upon the deformation. However, it seems that the predicted ground state deformation will remain the same in the four approaches.

  6. Description of odd-mass nuclei within the interacting boson-fermion model based on the Gogny energy density functional

    NASA Astrophysics Data System (ADS)

    Nomura, K.; Rodríguez-Guzmán, R.; Robledo, L. M.

    2017-07-01

    Spectroscopic properties of odd-mass nuclei are studied within the framework of the interacting boson-fermion model (IBFM) with parameters based on the Hartree-Fock-Bogoliubov (HFB) approximation. The parametrization D1M of the Gogny energy density functional (EDF) was used at the mean-field level to obtain the deformation energy surfaces for the considered nuclei in terms of the quadrupole deformations (β ,γ ). In addition to the energy surfaces, both single-particle energies and occupation probabilities were used as a microscopic input for building the IBFM Hamiltonian. Only three strength parameters for the particle-boson-core coupling are fitted to experimental spectra. The IBFM Hamiltonian is then used to compute the energy spectra and electromagnetic transition rates for selected odd-mass Eu and Sm nuclei as well as for 195Pt and 195Au. A reasonable agreement with the available experimental data is obtained for the considered odd-mass nuclei.

  7. 12. 3-min /sup 256/Cf and 43-min /sup 258/Md and systematics of the spontaneous fission propertiesof heavy nuclides

    SciTech Connect

    Hoffman, D.C.; Wilhelmy, J.B.; Weber, J.; Daniels, W.R.; Hulet, E.K.; Lougheed, R.W.; Landrum, J.H.; Wild, J.F.; Dupzyk, R.J.

    1980-03-01

    The new isotope 12.3-min /sup 256/Cf was produced via the /sup 254/Cf(t,p) reaction, and a new 43-min isomer of /sup 258/Md was produced via the /sup 255/Es(..cap alpha..,n) reaction. The fragment mass and kinetic energy distributions from the spontaneous fission of /sup 256/Cf were found to be very similar to those from the spontaneous fission of lighter Cf isotopes. The mass division is primarily asymmetric, and the average total kinetic energy is 189.8 +- 0.9 MeV. The 43-min /sup 258/Md presumably decays by electron capture and provides an opportunity to study the mass and kinetic energy distributions from the spontaneous fission of the 380-..mu..s /sup 258/Fm daughter. The observed narrow, symmetric mass distribution and the most probable total kinetic energy of 238 +- 3 MeV are similar to those reported for the spontaneous fission of /sup 259/Fm but show a sharp increase in symmetric mass division and total kinetic energy compared to /sup 257/Fm and the lighter Fm isotopes. No such abrupt change in properties was observed for /sup 256/Cf, which, like /sup 258/Fm, has 158 neutrons. The marked difference between the spontaneous fission properties of the heavier Fm isotopes and those of other spontaneously fissioning nuclides is compared to some theoretical predictions.

  8. Nuclide Guide and International Chart of Nuclides - 2008

    NASA Astrophysics Data System (ADS)

    Golashvili, T.

    2009-08-01

    New versions of Nuclide Guide and Chart of the Nuclides were developed as a result of Russian-Chinese collaboration. The Nuclide Guide contains the basic information on more than 3000 radioactive and stable nuclides. The characteristics of isomers with half-lives more than 1 ms are included. For each nuclide spin, parity, mass of nuclide, magnetic moment (if available), mass excess, half-life or abundance, decay modes, branching ratios, emitted particles, energies of most intense gamma-rays and their intensities, decay energies and mean values of radiation energy per decay are given. For stable and natural long-lived nuclides cross-sections of thermal neutron induced activation are indicated. The information presented in the Guide was compiled from 5 sources: 1) ENSDF-2008, 2) atomic mass evaluation-2005 by Audi and Wapstra, 3) interactive data bases at web-sites , , 4) original evaluations of authors, 5) recent publications. The International Chart ot Nuclides was developed on the basis of information presented in Nuclide Guide.

  9. Microscopic investigation of the low-lying magnetic dipole transitions in the odd-mass 155-169Ho isotopes

    NASA Astrophysics Data System (ADS)

    Tabar, E.; Kuliev, A.

    2017-08-01

    The low-lying magnetic dipole (M1) strength in deformed odd-mass 155-169Ho nuclei is investigated using rotational invariant (RI-) Quasiparticle Phonon Nuclear Model (QPNM). The gross features and fragmentation of the scissors mode in 165Ho is well reproduced by RI-QPNM calculations. The systematics of the low-energy M1 excitation in Ho isotopic chain is discussed with respect to summed strength. Besides, the results for M1 excitations in odd-mass Ho isotopes are compared with the systematics of the scissors mode in the neighbouring even-even nuclei. The obtained results generally match the systematic and trends typical for the scissors motion. In addition to the low-lying M1 excitations, a M1 giant resonance in the 7-15 MeV energy region is predicted for 155-169Ho nuclei in the present study.

  10. Low energy E0 transitions in odd-mass nuclei of the neutron deficient 180 < A < 200 region

    SciTech Connect

    Zganjar, E.F.; Kortelahti, M.O.; Wood, J.L.; Papanicolopulos, C.D.

    1987-01-01

    The region of neutron-deficient nuclei near Z = 82 and N = 104 provides the most extensive example of low-energy shape coexistence anywhere on the mass surface. It is shown that E0 and E0 admixed transitions may be used as a fingerprint to identify shape coexistence in odd-mass nuclei. It is also shown that all the known cases of low energy E0 and E0 admixed transitions in odd-mass nuclei occur where equally low-lying O/sup +/ states occur in neighboring even-even nuclei. A discussion of these and other relevant data as well as suggestions for new studies which may help to clarify and, more importantly, quantify the connection between E0 transitions and shape coexistence are presented. 60 refs., 7 figs., 4 tabs.

  11. Chart of the Nuclides

    SciTech Connect

    Sartori, Enrico

    1999-03-23

    Nucleus is an interactive PC-based graphical viewer of NUBASE nuclear property data. NUBASE contains experimentally known nuclear properties, together with some values that have been estimated from extrapolation of experimental data for 3010 nuclides. NUBASE also contains data on those isomeric states that have half-lives greater than 1 millisecond; there are 669 such nuclides of which 58 have more than one isomeric state. The latest version of NUCLEUS-CHART has been corrected to include the names and the chemical symbols of the elements 104 to 109 that have been finally adopted by the Commission on Nomenclature of Inorganic Chemistry (CNIC) of the International Union of Pure and Applied Chemistry (IUPAC). They differ from those recommended by the same commission a few years before and that were widely used in the evaluations AME''95 and NUBASE''97. It results in some shuffling of the names and symbols, that may cause confusion in the near future. At AMDC we''ll be as careful as possible to try to avoid such confusion. In advance we apologize if any will occur in the future and recommend the user to always double check these few names.

  12. QPNM calculation for the ground state magnetic moments of odd-mass deformed nuclei: 157-167Er isotopes

    NASA Astrophysics Data System (ADS)

    Yakut, H.; Guliyev, E.; Guner, M.; Tabar, E.; Zenginerler, Z.

    2012-08-01

    A new microscopic method has been developed in the framework of the Quasiparticle-Phonon Nuclear Model (QPNM) in order to investigate spin polarization effects on the magnetic properties such as magnetic moment, intrinsic magnetic moment and effective gs factor of the ground state of odd-mass 157-167Er isotopes. The calculations were performed using both Tamm-Dancoff Approximation (TDA) and Quasiparticle Random-Phase Approximation (QRPA). Reasonably good agreement has been obtained between the QRPA results and the relevant experimental data. Furthermore the variation of the intrinsic magnetic moment gK values with the mass number A exhibits similar behavior for both theoretical and experimental results. From the compression of the calculated intrinsic magnetic moment values with the experimental data the spin-spin interaction parameter has been found as χ=(30/A) MeV for odd-mass 157-167Er isotopes. Our results clarify the possibility of using this new method to describe the magnetic properties of odd-mass deformed nuclei.

  13. Unconventional Nuclides for Radiopharmaceuticals

    PubMed Central

    Holland, Jason P.; Williamson, Matthew J.; Lewis, Jason S.

    2016-01-01

    Rapid and widespread growth in the use of nuclear medicine for both diagnosis and therapy of disease has been the driving force behind burgeoning research interests in the design of novel radiopharmaceuticals. Until recently, the majority of clinical and basic science research has focused on the development of 11C-, 13N-, 15O-, and 18F-radiopharmaceuticals for use with positron emission tomography (PET) and 99mTc-labeled agents for use with single-photon emission computed tomography (SPECT). With the increased availability of small, low-energy cyclotrons and improvements in both cyclotron targetry and purification chemistries, the use of “nonstandard” radionuclides is becoming more prevalent. This brief review describes the physical characteristics of 60 radionuclides, including β+, β−, γ-ray, and α-particle emitters, which have the potential for use in the design and synthesis of the next generation of diagnostic and/or radiotherapeutic drugs. As the decay processes of many of the radionuclides described herein involve emission of high-energy γ-rays, relevant shielding and radiation safety issues are also considered. In particular, the properties and safety considerations associated with the increasingly prevalent PET nuclides 64Cu, 68Ga, 86Y, 89Zr, and 124I are discussed. PMID:20128994

  14. Bloch-Sensitive Nuclides

    NASA Astrophysics Data System (ADS)

    Chubb, Talbot A.

    2005-03-01

    Documented condensed matter nuclear science includes Fleischmann and Pons radiationless dd fusion reactions, Iwamura alpha-addition transmutations, and Oriani MeV particle showers. All require partitioned coherent matter in which fractions of each single ``wave like" particle are entangledootnotetextT. A. Chubb, ``Bloch Nuclides, Iwamura Transmutations, and Oriani Showers", ICCF11 Abstract. If the work required to bring side-by-side deuterons into contact is somehow reduced enough, an energy-minimizing 2-body anti-correlation form of wave function replaces the "molecule" configuration, allowing cold fusion. In the Iwamura process, a second fusion step fuses 2 spin-zero ^4He^2^+Bloch ions to form ^8Be^4^+Bloch. The nuclear ground state energy of the product nucleus is a function of the number of fragments into which it is partitioned. It is ``Bloch sensitive", i.e., its energy level is a function of Nwell, the number of potential wells into which the ^8Be^4^+Bloch is partitioned. The dependence of energy on lattice parameter Nwell strongly couples nuclear and electromagnetic forces at the boundary of the coherently ordered volume, causing energy transfer to the lattice.

  15. Karlsruhe nuclide chart - new 9. edition 2015

    SciTech Connect

    Soti, Zsolt; Magill, Joseph; Pfennig, Gerda; Derher, Raymond

    2015-07-01

    Following the success of the 8. Edition of the Karlsruhe Nuclide Chart 2012, a new edition is planned for 2015. Since the 2012 edition, more than 100 nuclides have been discovered and about 1400 nuclides have been updated. In summary, the new 9. edition contains decay and radiation data on approximately 3230 ground state nuclides and 740 isomers from 118 chemical elements. The accompanying booklet provides a detailed explanation of the nuclide box structure used in the Chart. An expanded section contains many additional nuclide decay schemes to aid the user to interpret the highly condensed information in the nuclide boxes. The booklet contains - in addition to the latest values of the physical constants and physical properties - a periodic table of the elements, tables of new and updated nuclides, and a difference chart showing the main changes in the Chart graphically. (authors)

  16. 2016 Update of the discoveries of nuclides

    NASA Astrophysics Data System (ADS)

    Thoennessen, M.

    The 2016 update of the discovery of nuclide project is presented. Only 12 new nuclides were observed for the first time in 2016. A large number of isotopes are still only published in conference proceedings or internal reports. No changes to earlier assignments were made.

  17. Rotational structure of the odd-proton nuclide 171Tm: A projected shell model study

    NASA Astrophysics Data System (ADS)

    Liu, YanXin; Chen, FangQi; Yu, ShaoYing; Sun, Yang

    2015-05-01

    Deformed odd-mass nuclei are ideal examples where the interplay between single-particle and collective degrees of freedom can be studied. Inspired by the recent experimental high-spin data in the odd-proton nuclide 171Tm, we perform projected shell model (PSM) calculations to investigate structure of the ground band and other bands based on isomeric states. In addition to the usual quadrupole-quadrupole force in the Hamiltonian, we employ the hexadecapole-hexadecapole ( HH) interaction, in a self-consistent way with the hexadecapole deformation of the deformed basis. It is found that the known experimental data can be well described by the PSM calculation. The effect of the HH force on the quasiparticle isomeric states is discussed.

  18. New nuclide sup 263 Ha

    SciTech Connect

    Kratz, J.V.; Gober, M.K.; Zimmermann, H.P. ); Schaedel, M.; Bruechle, W.; Schimpf, E. ); Gregorich, K.E.; Tuerler, A.; Hannink, N.J.; Czerwinski, K.R.; Kadkhodayan, B.; Lee, D.M.; Nurmia, M.J.; Hoffman, D.C. ); Gaeggeler, H.; Jost, D.; Kovacs, J.; Scherer, U.W.; Weber, A. )

    1992-03-01

    A new nuclide {sup 263}Ha was produced in the bombardment of a {sup 249}Bk target with 93-MeV {sup 18}O ions. It was detected via spontaneous fission counting and was shown to have a half-life of about 0.5 min. This activity was also separated from the reaction products by automated rapid chemical separations using cation-exchange chromatography in 0.05{ital M} {alpha}-hydroxyisobutyric acid. After chemical separation, {sup 263}Ha was found to decay by spontaneous fission (57{sub {minus}15}{sup +13}%) and by {alpha} emission ({ital E}{sub {alpha}}=8.35 MeV, 43%) with a half-life of 27{sub {minus}7}{sup +10} s. The spontaneous fission fragment energy spectrum is compatible with an average total kinetic energy of about 200 MeV.

  19. Cosmogenic Nuclides Study of Large Iron Meteorites

    NASA Astrophysics Data System (ADS)

    Hutzler, A.; Smith, T.; Rochette, P.; Bourles, D. L.; Leya, I.; Gattacceca, J.

    2014-09-01

    Six large iron meteorites were selected (Saint-Aubin, Mont-Dieu, Caille, Morasko, Agoudal, and Gebel Kamil). We measured stable and radiogenic cosmogenic nuclides, to study pre-atmospheric size, cosmic-ray exposure ages and terrestrial ages.

  20. Surficial Studies of Mars Using Cosmogenic Nuclides

    NASA Technical Reports Server (NTRS)

    Nishiizumi, K.

    2001-01-01

    Cosmogenic nuclides (CNs) are produced by cosmic-ray nuclear interactions with target nuclei in rocks, soils, ice, and the atmosphere. Cosmogenic nuclides have been widely used for investigation of solar system matter for several decades. Stable nuclides, such as He-3, Ne-21, and Ar-38, are built up over time as the surface is exposed to cosmic rays. The concentrations of cosmogenic radionuclides, such as Be-10, Al-26, and C-14 also build up with exposure time but reach saturation values after several half-lives. Especially since the development of accelerator mass spectrometry (AMS), CNs in terrestrial samples have been routinely used for geomorphic studies such as glaciation, surface erosion, and tectonics, and studies of atmospheric and ocean circulation. Cosmogenic nuclides on Mars will be able to answer questions of exposure ages, erosion rates, tectonic events, and deposition rates of sediments and/or volatiles. The concentrations of cosmogenic stable nuclides give the integrated exposure time of the rock/mineral, and the activities of radionuclides give recent records for times back as long as a few half-lives.

  1. Surficial Studies of Mars Using Cosmogenic Nuclides

    NASA Technical Reports Server (NTRS)

    Nishiizumi, K.

    2001-01-01

    Cosmogenic nuclides (CNs) are produced by cosmic-ray nuclear interactions with target nuclei in rocks, soils, ice, and the atmosphere. Cosmogenic nuclides have been widely used for investigation of solar system matter for several decades. Stable nuclides, such as He-3, Ne-21, and Ar-38, are built up over time as the surface is exposed to cosmic rays. The concentrations of cosmogenic radionuclides, such as Be-10, Al-26, and C-14 also build up with exposure time but reach saturation values after several half-lives. Especially since the development of accelerator mass spectrometry (AMS), CNs in terrestrial samples have been routinely used for geomorphic studies such as glaciation, surface erosion, and tectonics, and studies of atmospheric and ocean circulation. Cosmogenic nuclides on Mars will be able to answer questions of exposure ages, erosion rates, tectonic events, and deposition rates of sediments and/or volatiles. The concentrations of cosmogenic stable nuclides give the integrated exposure time of the rock/mineral, and the activities of radionuclides give recent records for times back as long as a few half-lives.

  2. Production systematics of cosmogenic nuclides in the earth

    SciTech Connect

    Reedy, R.C.

    1995-01-01

    The high-energy particles in the galactic cosmic rays, (GCR) can produce nuclides deep in any object exposed to them. These cosmic-ray-produced (cosmogenic) nuclides have been extensively studied during the last four decades, mainly in meteorites and lunar samples (e.g., 1,2). In extraterrestrial matter, several approaches have been used to determine the production systematics of these cosmogenic nuclides. Production rates of most cosmogenic nuclides in the Earth axe much lower, especially those nuclides made ``in situ`` in the Earth`s surface. Many of these @trial cosmogenic nuclides are only now being measured because of improved techniques, such as accelerator mass spectrometry (AMS). There have been very few determinations of the production rates of nuclides made in the Earth by cosmic rays. The work being done for terrestrial cosmogenic nuclides is following the approaches used for, studying the production of extraterrestrial nuclides.

  3. Light nuclides produced in the proton-induced spallation of {sup 238}U at 1 GeV

    SciTech Connect

    Ricciardi, M.V.; Armbruster, P.; Enqvist, T.; Kelic, A.; Rejmund, F.; Schmidt, K.-H.; Yordanov, O.; Benlliure, J.; Pereira, J.; Bernas, M.; Mustapha, B.; Stephan, C.; Tassan-Got, L.

    2006-01-15

    The production of light and intermediate-mass nuclides formed in the reaction {sup 1}H+{sup 238}U at 1 GeV was measured at the Fragment Separator at GSI, Darmstadt. The experiment was performed in inverse kinematics, by shooting a 1 A GeV {sup 238}U beam on a thin liquid-hydrogen target. A total of 254 isotopes of all elements in the range 7{<=}Z{<=}37 were unambiguously identified, and the velocity distributions of the produced nuclides were determined with high precision. The results show that the nuclides are produced in a very asymmetric binary decay of heavy nuclei originating from the spallation of uranium. All the features of the produced nuclides merge with the characteristics of the fission products as their mass increases.

  4. Delta I = 1 staggering effect for negative parity rotational bands with K = 1/2 in W/Os/Pt odd-mass nuclei

    NASA Astrophysics Data System (ADS)

    Taha, M. M.

    2015-11-01

    The anomalous negative-parity bands of odd-mass nuclei W/Os/Pt for N = 103 isotones are studied within the framework of particle rotor model (PRM). The phenomenon of Δ I = 1 staggering or signature splitting in energies occurs as one plots the gamma transitional energy over spin (EGOS) versus spin for the 1/2-[521] band originating from N = 5 single particle orbital. The rotational band with K = 1/2 separates into two signature partners. The levels with I = 1/2, 5/2, 9/2,… are displaced relatively to the levels with I = 3/2,7/2,11/2,…. The deviations of the level energies from the rigid rotor values is described by Coriolis coupling.

  5. Cosmogenic nuclides in the Brenham pallasite

    NASA Astrophysics Data System (ADS)

    Honda, M.; Caffee, M. W.; Miura, Y. N.; Nagai, H.; Nagao, K.; Nishiizumi, K.

    2002-12-01

    Cosmic-ray-produced (cosmogenic) nuclides were studied in fragments of the Brenham pallasite, a large stony iron meteorite. The contents of light noble gases (He, Ne, and Ar) and long-lived radionuclides (10Be, 26Al, 36Cl, and 53Mn), produced by nuclear reactions with cosmic rays, were measured in the separated metal and olivine phases from numerous samples representing a wide range of shielding conditions in the meteoroid. The distribution of cosmogenic nuclide concentrations in the metal follows patterns similar to that observed in large iron meteorites. Shielding effects were estimated from the relative proportions of low- and high-energy reaction products. The production rates varied, from surface to interior, by a factor of more than several hundred. The 36Cl-36Ar cosmic-ray exposure age of Brenham is 156 +/- 8 Myr. This determination is based on a multiple nuclide approach that utilizes cosmogenic nuclide pairs. This approach not only yields a "shielding independent" exposure age but also demonstrates that the production of cosmogenic nuclides occurred in a single stage. The depth profiles of 10Be in the stone phase and 53Mn in the metal phase are shown superimposed on corresponding profiles from the Apollo 15 long drill core. Surprisingly low abundances of lithophile elements, such as K, U, and Th, provided a unique opportunity to examine the production systematics of those nuclides whose inventories typically have significant contributions from non-cosmogenic sources, particularly radiogenic contributions. The U and Th contents of the olivine samples are extremely low, allowing detection of cosmogenic 4He production from oxygen, magnesium, silicon, and iron.

  6. Cosmogenic nuclide budgeting of floodplain sediment transfer

    NASA Astrophysics Data System (ADS)

    Wittmann, H.; von Blanckenburg, F.

    2009-08-01

    Cosmogenic nuclides produced in quartz may either decay or accumulate while sediment is moved through a river basin. A change in nuclide concentration resulting from storage in a floodplain is potentially important in large drainage basins in which sediment is prone to repeated burial and remobilization as a river migrates through its floodplain. We have modeled depth- and time-dependent cosmogenic nuclide concentration changes for 10Be, 26Al, and 14C during sediment storage and mixing in various active floodplain settings ranging from confined, shallow rivers with small floodplains to foreland-basin scale floodplains traversed by deep rivers. Floodplain storage time, estimated from channel migration rates, ranges from 0.4 kyr for the Beni River basin (Bolivia) to 7 kyr for the Amazon River basin, while floodplain storage depth, estimated from channel depth, ranges from 1 to 25 m. For all modeled active floodplain settings, the long-lived nuclides 10Be and 26Al show neither significant increase in nuclide concentration from irradiation nor decrease from decay. We predict a hypothetical response time after which changes in 10Be or 26Al concentrations become analytically resolvable. This interval ranges from 0.07 to 2 Myr and exceeds in all cases the typical residence time of sediment in a floodplain. Due to the much shorter half life of 14C, nuclide concentrations modeled for the in situ-produced variety of this nuclide are, however, sensitive to floodplain storage on residence times of < 20 kyr. The cosmogenic nuclide composition of old deposits in currently inactive floodplains that have been isolated for periods of millions of years from the river that once deposited them is predicted to either increase or decrease in 10Be and 26Al concentration, depending on the depositional depth. These conditions can be evaluated using the 26Al/ 10Be ratio that readily discloses the depth and duration of storage. We illustrate these models with examples from the Amazon basin

  7. Heavy cluster decay of trans-zirconium ``stable'' nuclides

    NASA Astrophysics Data System (ADS)

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

    1985-12-01

    By using the analytical superasymmetric fission model it is shown that all ``stable'' nuclei lighter than lead with Z>40 are metastable relative to the spontaneous emission of nuclear clusters. An even-odd effect is included in the zero point vibration energy. Half-lives in the range 1040-1050 s are obtained for Z>62. The region of metastability against these new decay modes is extended beyond that for α decay and in some cases, in the competing region, the emission rates for nuclear clusters are larger than for α decay.

  8. Neutron multiplicities for the transplutonium nuclides

    SciTech Connect

    Holden, N.E.; Zucker, M.S.

    1985-01-01

    This paper continues, with respect to the transplutonium nuclides, earlier efforts to collate and evaluate data from the scientific literature on the prompt neutron multiplicity distribution from fission and its first moment = ..sigma..nuPnu. The isotopes considered here for which P/sub nu/ and or data (or both) were found in the literature are of americium (Am), curium (Cm), berkelium (Bk), californium (Cf), einsteinium (Es), fermium (Fm), and nobelium (No).

  9. Chart of Nuclides from the National Nuclear Data Center (NNDC)

    DOE Data Explorer

    The Chart of Nuclides is a software product that allows users to search and plot nuclear structure and nuclear decay data interactively. The Chart of Nuclides was developed by the National Nuclear Data Center (NNDC). It provides an interface between web users and several databases containing nuclear structure, nuclear decay and some neutron-induced nuclear reaction information. Using the Chart of Nuclides, it is possible to search for nuclear level properties (energy, half-life, spin-parity), gamma-ray information (energy, intensity, multipolarity, coincidences),radiation information following nuclear decay (energy, intensity, dose), and neutron-induced reaction data from the BNL-325 book (thermal cross section and resonance integral). The information provided by the Chart of Nuclides can be seen in tables, level schemes and an interactive chart of nuclides. (From the Chart of Nuclides Description at http://www.nndc.bnl.gov/chart/help/index.jsp?product=chart)

  10. Application of different nuclides in retrospective dosimetry

    SciTech Connect

    Konheiser, J.; Mittag, S.; Viehrig, H.W.; Gleisberg, B.

    2011-07-01

    The activities of nuclides produced via the neutron irradiation of reactor pressure vessel (RPV) steel are used to validate respective fluence calculations. Niobium, nickel, and technetium isotopes from RPV trepans of the decommissioned NPP Greifswald (VVER-440) have been analyzed. The activities were determined by TRAMO (Monte-Carlo) fluence calculations, newly applying 640 neutron-energy groups and ENDF/B7 data. Relative to earlier results, fluences up to 20% higher have been computed, leading to somewhat better agreement between measurement and calculation, particularly in the case of Tc-99. (authors)

  11. Mass measurements of exotic nuclides at SHIPTRAP

    SciTech Connect

    Block, M.; Ackermann, D.; Eliseev, S.; Herfurth, F.; Hessberger, F. P.; Hofmann, S.; Kluge, H.-J.; Maero, G.; Martin, A.; Mazzocco, M.; Mukherjee, M.; Quint, W.; Rahaman, S.; Rauth, C.; Rodriguez, D.; Scheidenberger, C.; Vorobjev, G.; Blaum, K.; Ferrer, R.; Weber, C.

    2007-05-22

    The Penning trap mass spectrometer SHIPTRAP is installed behind the velocity-filter SHIP at GSI for high-precision mass measurements of fusion-evaporation residues. To facilitate an efficient stopping of the reaction products a buffer gas stopping cell is utilized. In an investigation of neutron-deficient nuclides in the terbium-to-thulium region around A {approx_equal} 146, 18 new or improved mass values have been obtained, resulting in a more accurate determination of the proton drip line for holmium and thulium. With the present performance of SHIPTRAP, a first direct mass measurement of transuranium elements in the nobelium region is within reach.

  12. Mass Evaluation for Proton Rich Nuclides

    SciTech Connect

    Wang, M.; Audi, G.; Xu, X.; Pfeiffer, B.; Kondev, F. G.

    2011-11-30

    The Atomic mass evaluation (AME) provides the reliable resource for the values related to atomic masses. Since the publication of the latest version of AME in 2003, many developments for atomic mass determination have been done and important results changed significantly our knowledge. A preliminary version of AME was released in April 2011, and an official version is foreseen to be published in early 2013. The general status of AME is presented and some specific features of AME for proton-rich nuclides are discussed.

  13. 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.

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

    NASA Astrophysics Data System (ADS)

    Robledo, L. M.

    2015-10-01

    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 254No. These are two and four-quasiparticle excitations that are treated in the same self-consistent HFB plus blocking framework as the odd mass states.

  15. Prompt neutron multiplicities for the transplutonium nuclides

    SciTech Connect

    Holden, N.E.; Zucker, M.S.

    1985-01-01

    The direct determination of the average prompt neutron emission values is reviewed, and a method of comparing different sites of neutron emission multiplicity distribution values is described. Measured and recommended values are tabulated for these nuclides: /sup 241/Am, /sup 242/Am, /sup 242/Cm, /sup 243/Cm, /sup 244/Cm, /sup 246/Cm, /sup 247/Cm, /sup 248/Cm, /sup 250/Cm, /sup 245/Cm, /sup 249/Bk, /sup 246/Cf, /sup 249/Cf, /sup 250/Cf, /sup 252/Cf, /sup 254/Cf, /sup 251/Cf, /sup 253/Es, /sup 254/Es, /sup 244/Fm, /sup 246/Fm, /sup 255/Fm, /sup 252/No, /sup 254/Fm, /sup 256/Fm, /sup 257/Fm. 59 refs., 24 tabs. (LEW)

  16. Cosmogenic nuclides in football-sized rocks.

    NASA Technical Reports Server (NTRS)

    Wahlen, M.; Honda, M.; Imamura, M.; Fruchter, J. S.; Finkel, R. C.; Kohl, C. P.; Arnold, J. R.; Reedy, R. C.

    1972-01-01

    The activity of long- and short-lived isotopes in a series of samples from a vertical column through the center of rock 14321 was measured. Rock 14321 is a 9 kg fragmental rock whose orientation was photographically documented on the lunar surface. Also investigated was a sample from the lower portion of rock 14310, where, in order to study target effects, two different density fractions (mineral separates) were analyzed. A few nuclides in a sample from the comprehensive fines 14259 were measured. This material has been collected largely from the top centimeter of the lunar soil. The study of the deep samples of 14321 and 14310 provided values for the activity of isotopes at points where only effects produced by galactic cosmic rays are significant.

  17. Nuclide production in (very) small meteorites

    NASA Technical Reports Server (NTRS)

    Arnold, J. R.; Nishiizumi, K.

    1986-01-01

    One of the most interesting open questions in the study of cosmic-ray effects in meteorites is the expected behavior of objects which are very small compared to the mean interaction length of primary galactic cosmic ray (GCR) particles. A reasonable limit might be a pre-atmospheric radius of 5 gram/cm(2), or 1.5 cm for chondrites. These are interesting for at least three reasons: (1) this is a limiting case for large objects, and can help us make better models; (2) this size is intermediate between usual meteorites and irradiated grams (spherules); and (3) these are the most likely objects to show solar cosmic ray (SCR) effects. Reedy (1984) has recently proposed a model for production by GCR of radioactive and stable nuclides in spherical meteorites. Very small objects are expected to deviate from this model in the direction of fewer secondary particles (larger spectral shape parameter), at all depths. The net effect will be significantly lower production of such low-energy products as Mn-53 and Al-26. The SCR production of these and other nuclides will be lower, too, because meteorite orbits extend typically out into the asteroid belt, and the mean SCR flux must fall off approximately as r(-2) with distance from the Sun. Kepler's laws insure that for such orbits most of the exposure time is spent near aphelion. None the less the equivalent mean exposure distance, R(exp), is slightly less than the semimajor axis A because of the weighting by R(-2). For the three meteorite orbits we have, R(exp) has a narrow range, from about 1.6 to 2.1 a.u. This is probably true for the great majority of meteorites.

  18. Particle-hole intruder levels in 67Cu, collectivity, monopole shifts, and the hockey-stick behaviour of ell - 1/2 5/2- levels in neutron-rich odd-mass Cu nuclei

    NASA Astrophysics Data System (ADS)

    Walters, W. B.; Chiara, C. J.

    2011-01-01

    A new sequence of gamma rays with energies of 572, 499, 585, and 674 keV has been identified in 67Cu populating the 7/2- level at 2362 keV. Owing to the strong population of the 2362-keV level via an ell = 3 proton pickup reaction, that level is assigned to be an f7/2-1 2-particle-1-hole "intruder" proton configuration, and the new levels are found to form a sequence consistent with intruder sequences in the adjacent odd-mass Cu isotopes and in the odd-mass Sb isotopes. The changing position of the intruder sequence in the odd-mass Cu isotopes is discussed and related to the onset of collectivity associated with the presence of g9/2 neutrons beyond N = 40. The increase in collectivity is also discussed for a number of isotonic and isotopic chains as more protons or neutrons, respectively, are added beyond an oscillator shell boundary. For most of these systems, the ell -1/2 levels show a systematic "hockey-stick-like" behaviour with a sharp decrease in energy with the addition of the first protons or neutrons, owing to both the added collectivity and the tensor interaction, and then a lower slope when collectivity changes are diminished and only the tensor interaction is influencing the changes in level positions.

  19. Dependence of nuclear quadrupole resonance transitions on the electric field gradient asymmetry parameter for nuclides with half-integer spins

    SciTech Connect

    Cho, Herman

    2016-02-28

    Allowed transition energies and eigenstate expansions have been calculated and tabulated in numerical form as functions of the electric field gradient asymmetry parameter for the zero field Hamiltonian of quadrupolar nuclides with I = 3/2,5/2,7/2, and 9/2. These results are essential to interpret nuclear quadrupole resonance (NQR) spectra and extract accurate values of the electric field gradient tensors. Furthermore, applications of NQR methods to studies of electronic structure in heavy element systems are proposed.

  20. Dependence of nuclear quadrupole resonance transitions on the electric field gradient asymmetry parameter for nuclides with half-integer spins

    NASA Astrophysics Data System (ADS)

    Cho, Herman

    2016-09-01

    Allowed transition energies and eigenstate expansions have been calculated and tabulated in numerical form as functions of the electric field gradient asymmetry parameter for the zero field Hamiltonian of quadrupolar nuclides with I = 3 / 2 , 5 / 2 , 7 / 2, and 9 / 2. These results are essential to interpret nuclear quadrupole resonance (NQR) spectra and extract accurate values of the electric field gradient tensors. Applications of NQR methods to studies of electronic structure in heavy element systems are proposed.

  1. Alpha-emitting nuclides in the marine environment

    NASA Astrophysics Data System (ADS)

    Pentreath, R. J.

    1984-06-01

    The occurrence of alpha-emitting nuclides and their daughter products in the marine environment continues to be a subject of study for many reasons. Those nuclides which occur naturally, in the uranium, thorium and actinium series, are of interest because of their value in determining the rates of geological and geochemical processes in the oceans. Studies of them address such problems as the determination of rates of transfer of particulate matter, deposition rates, bioturbation rates, and so on. Two of the natural alpha-series nuclides in which a different interest has been expressed are 210Po and 226Ra, because their concentrations in marine organisms are such that they contribute to a significant fraction of the background dose rates sustained both by the organisms themselves and by consumers of marine fish and shellfish. To this pool of naturally-occurring nuclides, human activities have added the transuranium nuclides, both from the atmospheric testing of nuclear devices and from the authorized discharges of radioactive wastes into coastal waters and the deep sea. Studies have therefore been made to understand the chemistry of these radionuclides in sea water, their association with sedimentary materials, and their accumulation by marine organisms, the last of these being of particular interest because the transuranics are essentially "novel" elements to the marine fauna and flora. The need to predict the long-term behaviour of these nuclides has, in turn, stimulated research on those naturally-occurring nuclides which may behave in a similar manner.

  2. Nuclide production by primary cosmic-ray protons

    SciTech Connect

    Reedy, R.C.

    1986-01-01

    The production rates of cosmogenic nuclides in the solar system and in interstellar space were calculated for the primary protons in the galactic and solar cosmic rays. At 1 AU, the long-term average fluxes of solar protons usually produce many more atoms of a cosmogenic nuclide than the primary protons in the galactic cosmic rays (GCR), the exceptions being nuclides made only by high-energy reactions (like /sup 10/Be). Because the particle fluxes inside meteorites and other large objects in space include many secondary neutrons, the production rates are much higher and ratios inside large objects are often very different from those by just the primary GCR protons in small objects. The production rates of cosmogenic nuclides are calculated to vary by about factors of 2.5 during at typical 11-year solar cycle, in agreement with measurements of short-lived radionuclides in recently fallen meteorites. The production of cosmogenic nuclides by the GCR particles outside the heliosphere is higher than that by the modulated GCR primaries normally in the solar system. However, there is considerable uncertainty in the fluxes of interstellar protons and, therefore, in the production rates of cosmogenic nuclides in interstellar space. Production rates and ratios for cosmogenic nuclides would be able to identify particles that were small in space or that were exposed to an unmodulated spectrum of GCR particles. 25 refs., 2 figs., 2 tabs.

  3. Dependence of nuclear quadrupole resonance transitions on the electric field gradient asymmetry parameter for nuclides with half-integer spins

    SciTech Connect

    Cho, Herman

    2016-09-01

    Allowed transition energies and eigenstate expansions have been calculated and tabulated in numerical form as functions of the electric field gradient asymmetry parameter for the zero field Hamiltonian of quadrupolar nuclides with I = 3/2, 5/2, 7/2, and 9/2. These results may be used to interpret nuclear quadrupole resonance (NQR) spectra and extract accurate values of the electric field gradient tensors. Applications of NQR methods to studies of electronic structure in heavy element systems are proposed. This material is based upon work supported by the U.S. Department of Energy Office of Science, Office of Basic Energy Sciences, Heavy Element Chemistry program.

  4. (The fate of nuclides in natural water systems)

    SciTech Connect

    Turekian, K.K. . Dept. of Geology and Geophysics)

    1989-01-01

    Our research at Yale on the fate of nuclides in natural water systems has three components to it: the study of the atmospheric precipitation of radionuclides and other chemical species; the study of the behavior of natural radionuclides in groundwater and hydrothermal systems; and understanding the controls on the distribution of radionuclides and stable nuclides in the marine realm. In this section a review of our progress in each of these areas is presented.

  5. Solar-Cosmic-Ray-Produced Nuclides in Extraterrestrial Matter

    NASA Astrophysics Data System (ADS)

    Reedy, Robert C.

    2000-01-01

    There are two main types of cosmic rays that have sufficient energy to induce nuclear reactions -- the galactic cosmic rays (GCR) and solar cosmic rays (also called solar energetic particles). Both types of particles can have production rates and production ratios in the small objects often found in cold and hot deserts that are different from those seen for most meteorites, which typically have radii of approx.10-100 centimeters. GCR production rates are often lower than those for most meteorites. GCR production ratios, such as Ne-22/Ne-21, are also often different in small objects. Smaller meteoroids also are more likely to have nuclides made by solar-cosmic-ray (SCR) particles than typically-sized meteorites. The very small meteorite Salem had large amounts of SCR-produced radionuclides. Meteorites recovered in Antarctica are more likely to contain SCR-produced nuclides than other meteorites. Martian and lunar meteorites are also likely to have SCR-produced nuclides. Production rates and profiles for SCR-produced nuclides in meteoroids have been calculated previously. However, the cross sections for the nuclear reactions making many SCR-produced nuclides, such as Be-10, were not well measured then. New rates and profiles are calculated here using good cross sections for the reactions making these nuclides.

  6. Nuclear Properties and Decay Data Chart of Nuclides.

    SciTech Connect

    OSORIO, V. B.

    2008-04-04

    Version 00 NUCHART displays nuclear decay data graphically on a PC and, includes a search routine for assigning gamma-ray energies to radionuclides. The numerical data included in NUCHART were taken from the online database "NUDAT" Version of March 1994. The following information is presented: (1) Nuclide information: for each nuclide, abundance, mass excess, (main) decay mode, half-life and uncertainty, branching ratio, decay Q; (2) decay radiation: for each nuclide, tables of radiation energy, intensity and equivalent dose for the 5 most intense decay radiations of beta+, beta-, conversion electrons, gammas, alphas and x-rays, including electron Augers; (3) adopted gammas: for each nuclide, table containing energy, relative intensity, energy level of the main gamma lines and year of publication in Nuclear Data Sheets; (4) search gamma energies: for a specified interval of gamma energies all know gamma lines and their nuclides are displayed; the database contains 132,000 gamma lines; (5) a search mode by specific nuclide is also available. For the latest data and online tools for viewing the data, see NuDat 2.4 on the NNDC and IAEA NDS websites: http://www.nndc.bnl.gov/ and http://www-nds.iaea.org/.

  7. Algorithm Improvement Program Nuclide Identification Algorithm Scoring Criteria And Scoring Application - DNDO.

    SciTech Connect

    Enghauser, Michael

    2015-02-01

    The goal of the Domestic Nuclear Detection Office (DNDO) Algorithm Improvement Program (AIP) is to facilitate gamma-radiation detector nuclide identification algorithm development, improvement, and validation. Accordingly, scoring criteria have been developed to objectively assess the performance of nuclide identification algorithms. In addition, a Microsoft Excel spreadsheet application for automated nuclide identification scoring has been developed. This report provides an overview of the equations, nuclide weighting factors, nuclide equivalencies, and configuration weighting factors used by the application for scoring nuclide identification algorithm performance. Furthermore, this report presents a general overview of the nuclide identification algorithm scoring application including illustrative examples.

  8. Algorithm improvement program nuclide identification algorithm scoring criteria and scoring application.

    SciTech Connect

    Enghauser, Michael

    2016-02-01

    The goal of the Domestic Nuclear Detection Office (DNDO) Algorithm Improvement Program (AIP) is to facilitate gamma-radiation detector nuclide identification algorithm development, improvement, and validation. Accordingly, scoring criteria have been developed to objectively assess the performance of nuclide identification algorithms. In addition, a Microsoft Excel spreadsheet application for automated nuclide identification scoring has been developed. This report provides an overview of the equations, nuclide weighting factors, nuclide equivalencies, and configuration weighting factors used by the application for scoring nuclide identification algorithm performance. Furthermore, this report presents a general overview of the nuclide identification algorithm scoring application including illustrative examples.

  9. PRODUCTION CONSIDERATIONS FOR THE CLASSICAL PET NUCLIDES.

    SciTech Connect

    FINN,R.; SCHLYER,D.

    2001-06-25

    Nuclear Medicine is the specialty of medical imaging, which utilizes a variety of radionuclides incorporated into specific compounds for diagnostic imaging and therapeutic applications. During recent years, research efforts associated with this discipline have concentrated on the decay characteristics of particular radionuclides and the design of unique radiolabeled tracers necessary to achieve time-dependent molecular images. The specialty is expanding with specific Positron emission tomography (PET) and SPECT radiopharmaceuticals allowing for an extension from functional process imaging in tissue to pathologic processes and nuclide directed treatments. PET is an example of a technique that has been shown to yield the physiologic information necessary for clinical oncology diagnoses based upon altered tissue metabolism. Most PET drugs are currently produced using a cyclotron at locations that are in close proximity to the hospital or academic center at which the radiopharmaceutical will be administered. In November 1997, a law was enacted called the Food and Drug Administration Modernization Act of 1997 which directed the Food and Drug Administration (FDA) to establish appropriate procedures for the approval of PET drugs in accordance with section 505 of the Federal Food, Drug, and Cosmetic Act and to establish current good manufacturing practice requirements for such drugs. At this time the FDA is considering adopting special approval procedures and cGMP requirements for PET drugs. The evolution of PET radiopharmaceuticals has introduced a new class of ''drugs'' requiring production facilities and product formulations that must be closely aligned with the scheduled clinical utilization. The production of the radionuclide in the appropriate synthetic form is but one critical component in the manufacture of the finished radiopharmaceutical.

  10. Initial Test Determination of Cosmogenic Nuclides in Magnetite

    NASA Astrophysics Data System (ADS)

    Matsumura, H.; Caffee, M. W.; Nagao, K.; Nishiizumi, K.

    2014-12-01

    Long-lived radionuclides, such as 10Be, 26Al, and 36Cl, are produced by cosmic rays in surficial materials on Earth, and used for determinations of cosmic-ray exposure ages and erosion rates. Quartz and limestone are routinely used as the target minerals for these geomorphological studies. Magnetite also contains target elements that produce abundant cosmogenic nuclides when exposed to the cosmic rays. Magnetite has several notable merits that enable the measurement of cosmogenic nuclides: (1) the target elements for production of cosmogenic nuclides in magnetite comprise the dominant mineral form of magnetite, Fe3O4; (2) magnetite can be easily isolated, using a magnet, after rock milling; (3) multiple cosmogenic nuclides are produced by exposure of magnetite to cosmic-ray secondaries; and (4) cosmogenic nuclides produced in the rock containing the magnetite, but not within the magnetite itself, can be separated using nitric acid and sodium hydroxide leaches. As part of this initial study, magnetite was separated from a basaltic sample collected from the Atacama Desert in Chili (2,995 m). Then Be, Al, Cl, Ca, and Mn were separated from ~2 g of the purified magnetite. We measured cosmogenic 10Be, 26Al, and 36Cl concentrations in the magnetite by accelerator mass spectrometry at PRIME Lab, Purdue University. Cosmogenic 3He and 21Ne concentrations of aliquot of the magnetite were measured by mass spectrometry at the University of Tokyo. We also measured the nuclide concentrations from magnetite collected from a mine at Ishpeming, Michigan as a blank. The 10Be and 36Cl concentrations as well as 3He concentration produce concordant cosmic ray exposure ages of ~0.4 Myr for the Atacama basalt. However, observed high 26Al and 21Ne concentrations attribute to those nuclides incorporation from silicate impurity.

  11. Predicting the production rates of cosmogenic nuclides in extraterrestrial matter

    SciTech Connect

    Reedy, R.C.

    1987-01-01

    The production rates of nuclides made by the galactic and solar cosmic rays are important in the interpretations of measurements made with lunar samples, meteorites, and cosmic spherules. Production rates of cosmogenic nuclides have been predicted by a variety of methods that are reviewed in this paper, ranging from systematic studies of one or a group of meteorites to purely theoretical calculations. Production rates can vary with the chemical composition and the preatmospheric depth of the sample and with the size and shape of the object. While the production systematics for cosmogenic nuclides are fairly well known, our ability to predict their production rates can be improved, with a corresponding increase in the scientific return. Additional detailed studies of cosmogenic nuclides in extraterrestrial objects are needed, especially for fairly small and very large objects. Nuclides made in simulation experiments and cross sections for many major nuclear reactions should be measured. Such studies are especially needed for the long-lived radionuclides that have only recently become readily measurable by accelerator mass spectrometry. 34 refs., 5 figs.

  12. Variable temperature effects on release rates of readily soluble nuclides

    SciTech Connect

    Kim, C.-L.; Light, W.B.; Lee, W.W.-L.; Chambre, P.L.; Pigford, T.H.; Lawrence Berkeley Lab., CA )

    1988-09-01

    In this paper we study the effect of temperature on the release rate of readily soluble nuclides, as affected by a time-temperature dependent diffusion coefficient. In this analysis ground water fills the voids in the waste package at t = 0 and one percent of the inventories of cesium and iodine are immediately dissolved into the void water. Mass transfer resistance of partly failed container and cladding is conservatively neglected. The nuclides move through the void space into the surrounding rock under a concentration gradient. We use an analytic solution to compute the nuclide concentration in the gap or void, and the mass flux rate into the porous rock. 8 refs., 4 figs.

  13. Cratering and cosmogenic nuclides. [as function of depth in regolith

    NASA Technical Reports Server (NTRS)

    Blake, M. L.; Wasserburg, G. J.

    1975-01-01

    A simple probabilistic model was constructed for the average value of a cosmogenic nuclide as a function of depth in a regolith. An arbitrary function was chosen for the size distribution of craters. The resulting integro-differential equation was found to reduce in limiting cases to the marching equation with a characteristic residence time and to the diffusion equation. The regolith diffusion constant is shown to be a simple integral of the cratering rate weighted by geometrical terms. This formal treatment provides a direct and general connection between cosmogenic nuclides and cratering rates and crater population in a simple analytical form. The validity of this model remains to be tested.

  14. Cosmogenic nuclides in early solar system materials

    NASA Astrophysics Data System (ADS)

    Bricker, Glynn Edward

    2009-09-01

    The overall goal of this research was to assess early solar system processes, particularly ancient proto-solar activity. This goal was addressed on two fronts. First, a model was developed to explain the provenance of now extinct radionuclides in early solar system materials, namely the refractory inclusions termed CAIs (Calcium-Aluminum-Inclusion) found in carbonaceous chondrites. As CAIs are believed to be the first solids to condense in the solar system and are also believed to have formed close to the proto-Sun, a model which explains the now extinct radionuclides found in CAIs constrains early solar system processes. Secondly, a series of measurements were performed on samples of the early solar system, namely chrondritic meteorites and the inclusions called chondrules, often contained within these meteorites. Chondrules, which are often a chief constituent of these meteorites, are believed to have originated close to the proto-Sun. As such, these materials should contain clues about solar processes at the beginning of the solar system. We propose a model for the incorporation of SLRs (short lived radionuclide) within CAIs in primitive carbonaceous meteorites. In this model SLRs are produced by energetic particle reactions in the proto-solar atmosphere of a more active proto-Sun characterized by proton fluxes higher than contemporary particle fluxes. These SLRs are entrained in the solar wind that is then implanted into CAI precursor material. This production mechanism is operational in the contemporary solar system and is responsible for implantation of 10 Be, 14 C and other nuclides in lunar materials. We utilize contemporary experimental solar wind production rates for 10Be and 14 C and theoretical ancient production rates for 7 Be, 10 Be, 14 C, 26 Al, 36 Cl, 41 Ca, and 53 Mn. Using a ~ 10 5 enhancement in SEPs (solar energetic particles) and hence production rates in conjunction with an accepted refractory mass inflow rates close to the proto-Sun, we model

  15. Shielding and activity estimator for template-based nuclide identification methods

    DOEpatents

    Nelson, Karl Einar

    2013-04-09

    According to one embodiment, a method for estimating an activity of one or more radio-nuclides includes receiving one or more templates, the one or more templates corresponding to one or more radio-nuclides which contribute to a probable solution, receiving one or more weighting factors, each weighting factor representing a contribution of one radio-nuclide to the probable solution, computing an effective areal density for each of the one more radio-nuclides, computing an effective atomic number (Z) for each of the one more radio-nuclides, computing an effective metric for each of the one or more radio-nuclides, and computing an estimated activity for each of the one or more radio-nuclides. In other embodiments, computer program products, systems, and other methods are presented for estimating an activity of one or more radio-nuclides.

  16. Radio-nuclide mixture identification using medium energy resolution detectors

    DOEpatents

    Nelson, Karl Einar

    2013-09-17

    According to one embodiment, a method for identifying radio-nuclides includes receiving spectral data, extracting a feature set from the spectral data comparable to a plurality of templates in a template library, and using a branch and bound method to determine a probable template match based on the feature set and templates in the template library. In another embodiment, a device for identifying unknown radio-nuclides includes a processor, a multi-channel analyzer, and a memory operatively coupled to the processor, the memory having computer readable code stored thereon. The computer readable code is configured, when executed by the processor, to receive spectral data, to extract a feature set from the spectral data comparable to a plurality of templates in a template library, and to use a branch and bound method to determine a probable template match based on the feature set and templates in the template library.

  17. Production rates of terrestrial in-situ-produced cosmogenic nuclides

    SciTech Connect

    Reedy, R.C.; Tuniz, C.; Fink, D.

    1993-12-31

    Production rates of cosmogenic nuclides made in situ in terrestrial samples and how they are applied to the interpretation of measured radionuclide concentrations were discussed at a one-day Workshop held 2 October 1993 in Sydney, Australia. The status of terrestrial in-situ studies using the long-lived radionuclides {sup 10}Be, {sup 14}C, {sup 26}Al, {sup 36}Cl, and {sup 41}Ca and of various modeling and related studies were presented. The relative uncertainties in the various factors that go into the interpretation of these terrestrial in-situ cosmogenic nuclides were discussed. The magnitudes of the errors for these factors were estimated and none dominated the final uncertainty.

  18. Measurements of cosmogenic nuclides in lunar rock 64455

    NASA Technical Reports Server (NTRS)

    Arnold, J. R.; Kohl, C. P.; Nishiizumi, K.; Caffee, M. W.; Finkel, R. C.; Southon, J. R.

    1993-01-01

    Eleven samples were ground from the glass coated surface of lunar rock 64455,82 with an average depth resolution of 50 microns and were measured for Be-10, Al-26, and Cl-36 using AMS (accelerator mass spectrometry). Results show no evidence of SCR (solar cosmic ray) effects. The flat cosmogenic nuclide profiles and activity levels are consistent with a 2 My exposure history for the rock and a sample location on the bottom of the rock. These AMS measurements are some of the most precise ever obtained for these three nuclides. This precision and the demonstrated fine depth resolution will enable us to conduct a number of detailed studies of depth effects in lunar and meteoritic samples, including investigating SCR effects in the surface exposed top of the glass coating of 64455 and possibly in the underlying rock.

  19. Measurements of cosmogenic nuclides in lunar rock 64455

    NASA Technical Reports Server (NTRS)

    Arnold, J. R.; Kohl, C. P.; Nishiizumi, K.; Caffee, M. W.; Finkel, R. C.; Southon, J. R.

    1993-01-01

    Eleven samples were ground from the glass coated surface of lunar rock 64455,82 with an average depth resolution of 50 microns and were measured for Be-10, Al-26, and Cl-36 using AMS (accelerator mass spectrometry). Results show no evidence of SCR (solar cosmic ray) effects. The flat cosmogenic nuclide profiles and activity levels are consistent with a 2 My exposure history for the rock and a sample location on the bottom of the rock. These AMS measurements are some of the most precise ever obtained for these three nuclides. This precision and the demonstrated fine depth resolution will enable us to conduct a number of detailed studies of depth effects in lunar and meteoritic samples, including investigating SCR effects in the surface exposed top of the glass coating of 64455 and possibly in the underlying rock.

  20. Hot demonstration of proposed commercial nuclide removal technology

    SciTech Connect

    Lee, D.

    1996-10-01

    This task covers the development and operation of an experimental test unit located in a Building 4501 hot cell within Building 4501 at Oak Ridge National Laboratory (ORNL). This equipment is designed to test radionuclides removal technologies under continuous operatoin on actual ORNL Melton Valley Storage Tank (MVST) supernatant, Savannah River high-level waste supernatant, and Hanford supernatant. The latter two may be simulated by adding the appropriate chemicals and/or nuclides to the MVST supernatant.

  1. Automatic Software Processing for Inventories of Nuclides (ASPIN)

    SciTech Connect

    Luca Gratton; J.M. Rammsy

    2001-10-22

    EQ6 users have difficulties tracking isotopic concentrations in a system with chemical and nuclear decay reactions. The capability to track isotopic concentrations is particularly important for simulating the degradation of the spent nuclear fuels. Isotopic tracking is necessary to evaluate the criticality risk associated with fissile material relocation inside of a disposal container. A code called ASPRIN (Automatic Software PRocessing, Inventories of Nuclides) was created to allow isotopic tracking using the results of EQ6 simulations.

  2. Simulations of Terrestrial in-situ Cosmogenic-Nuclide Production

    NASA Technical Reports Server (NTRS)

    Reedy, R. C.; Nishiizumi, K.; Lal, D.; Arnold, J. R.; Englert, P. A. J.; Klein, J.; Middleton, R.; Jull, A. J. T.; Donahue, D. J.

    1994-01-01

    Targets of silicon and silicon dioxide were irradiated with spallation neutrons to simulate the production of long-lived radionuclides in the surface of the Earth. Gamma-ray spectroscopy was used to measure Be-7 and Na-22, and accelerator mass spectrometry was used to measure Be-10, C-14, and Al-26. The measured ratios of these nuclides are compared with calculated ratios and with ratios from other simulations and agree well with ratios inferred from terrestrial samples.

  3. Recent developments in cosmogenic nuclide production rate scaling

    NASA Astrophysics Data System (ADS)

    Lifton, N. A.

    2013-12-01

    A new cosmogenic nuclide production rate scaling model based on analytical fits to Monte Carlo simulations of atmospheric cosmic ray flux spectra (both of which agree well with measured spectra) enables identification and quantification of the biases in previously published models (Lifton, N., Sato, T., Dunai, T., in review, Earth and Planet. Sci. Lett.). Scaling predictions derived from the new model (termed LSD) suggest two potential sources of bias in the previous models: different energy responses of the secondary neutron detectors used in developing the models, and different geomagnetic parameterizations. In addition, the particle flux spectra generated by the LSD model allow one to generate nuclide-specific scaling factors that reflect the influences of the flux energy distribution and the relevant excitation functions (probability of nuclide production in a given nuclear reaction as a function of energy). Resulting scaling factors indicate 3He shows the strongest positive deviation from the flux-based scaling, while 14C exhibits a negative deviation. These results are consistent with previous studies showing an increasing 3He/10Be ratio with altitude in the Himalayas, but with a much lower magnitude for the effect. Furthermore, the new model provides a flexible framework for exploring the implications of future advances in model inputs. For example, the effects of recently updated paleomagnetic models (e.g. Korte et al., 2011, Earth and Planet Sci. Lett. 312, 497-505) on scaling predictions will also be presented.

  4. Nuclear fission of neutron-deficient protactinium nuclides

    SciTech Connect

    Nishinaka, I.; Nagame, Y.; Tsukada, K.; Ikezoe, H.; Sueki, K.; Nakahara, H.; Tanikawa, M.; Ohtsuki, T.

    1997-08-01

    Fragment velocity, kinetic energy, mass yield, and element yield distributions in the fission of neutron-deficient Pa isotopes produced in the reactions of {sup 16}O and {sup 18}O on {sup 209}Bi have been measured at incident beam energies near and above the Coulomb barriers by the time-of-flight and radiochemical methods. An asymmetric mass-division component has been observed. Measured fission cross sections were compared with the results of statistical model calculations which take into account two fission barrier heights for symmetric and asymmetric yields. The fission barrier height deduced for the asymmetric fission is found slightly lower than that for the symmetric one. The difference between the two barrier heights in the fission of the present protactinium nuclides (N{approximately}135) is considerably smaller than that in the neutron-rich nuclide of {sup 233}Pa (N{approximately}142), indicating that the difference sensitively depends on the neutron number of the fissioning nuclide. {copyright} {ital 1997} {ital The American Physical Society}

  5. The determination of critical nuclides in PWR waste streams

    SciTech Connect

    De Goeyse, A.

    1993-12-31

    The safety studies concerning the final disposal of low- and intermediate-level radioactive waste take into consideration a series of long-lived radionuclides. The problem the producers have to cope with comes from the fact that those nuclides, which are mainly (pure) {beta} emitters or {alpha} emitters, cannot be measured by a direct current method such as gamma scanning. Their determination involves sophisticated radiochemical techniques which are difficult to implement by a producer on a routine basis for normal production waste. A current method for the determination of those nuclides in the waste streams produced by a nuclear power reactor consists in applying correlation factors or scaling factors between those critical nuclides and so called key radionuclides, which can be easily measured and are representative for the occurrence of activation products and fission products in the waste streams. In order to identify and define those correlation factors, ONDRAF/NIRAS, has subcontracted, in agreement with the waste producer (ELECTRABEL), a complete study to the engineering company BELGATOM (BA) for the different waste streams produced by the seven Belgian PWR plants.

  6. Measurement of the yield of nuclides produced in the interaction of 1-GeV protons with a cylindrical lead target

    SciTech Connect

    Bakhmutkin, S.V.; Nosov, A.A.; Rimskii-Korsakov, A.A.

    1988-02-01

    In the last few years, the yield of nuclides produced in spallation and fission reactions by high-energy protons bombarding heavy-element targets with dimensions close to the path length has been determined. The development of computational techniques describing the nuclear cascade in such targets calls for a comparison with experimental results obtained in a relatively simple geometry. The goal of the present work was to obtain experimental data for selecting and correcting the parameters to be used in the calculations. The distributions were used to determine the yield of 22 nuclides for a cylindrical lead target with a diameter of 200 mm and a length of 600 mm; the distributions were expressed by the activity in saturation, induced by a primary proton beam with a current of 1 nA. The results of this determination are listed.

  7. Notre Dame Nuclear Database: A New Chart of Nuclides

    NASA Astrophysics Data System (ADS)

    Lee, Kevin; Khouw, Timothy; Fasano, Patrick; Mumpower, Matthew; Aprahamian, Ani

    2014-09-01

    Nuclear data is critical to research fields from medicine to astrophysics. We are creating a database, the Notre Dame Nuclear Database, which can store theoretical and experimental datasets. We place emphasis on storing metadata and user interaction with the database. Users are able to search in addition to the specific nuclear datum, the author(s), the facility where the measurements were made, the institution of the facility, and device or method/technique used. We also allow users to interact with the database by providing online search, an interactive nuclide chart, and a command line interface. The nuclide chart is a more descriptive version of the periodic table that can be used to visualize nuclear properties such as half-lives and mass. We achieve this by using D3 (Data Driven Documents), HTML, and CSS3 to plot the nuclides and color them accordingly. Search capabilities can be applied dynamically to the chart by using Python to communicate with MySQL, allowing for customization. Users can save the customized chart they create to any image format. These features provide a unique approach for researchers to interface with nuclear data. We report on the current progress of this project and will present a working demo that highlights each aspect of the aforementioned features. This is the first time that all available technologies are put to use to make nuclear data more accessible than ever before in a manner that is much easier and fully detailed. This is a first and we will make it available as open source ware.

  8. Simulations of terrestrial in-situ cosmogenic-nuclide production

    SciTech Connect

    Reedy, R.C.; Nishiizumi, K.; Arnold, J.R.; Lal, D.; Englert, P.A.J.; Klein, J.; Middleton, R.; Jull, A.J.T.; Donahue, D.J.

    1993-12-31

    Targets of silicon and silicon dioxide were irradiated with spallation neutrons to simulate the production of long-lived radionuclides in the surface of the earth. Gamma-ray spectroscopy was used to measure {sup 7}Be and {sup 22}Na, and accelerator mass spectrometry was used to measure {sup 10}Be, {sup 14}C, and {sup 26}Al. The measured ratios of these nuclides are compared with calculated ratios and with ratios from other simulations and agree well with ratios inferred from terrestrial samples.

  9. Time-of-Flight Mass Measurements of Neutron Rich Nuclides

    NASA Astrophysics Data System (ADS)

    Estrade, A.; Matos, M.; Amthor, A. M.; Becerril, A.; Elliot, T.; Lorusso, G.; Rogers, A.; Schatz, H.; Bazin, D.; Gade, A.; Portillo, M.; Stolz, A.; Galaviz, D.; Pereira, J.; Shapira, D.; Smith, E.; Wallace, M.

    2008-10-01

    Nuclear masses of neutron rich isotopes in the region of Z ˜ 20-30 have been measured using the time-of-flight technique at the National Superconducting Cyclotron Laboratory (NSCL). The masses of 5 isotopes have been measured for the first time, and the precision of several other masses has been improved. The time-of-flight technique has shown the potential to access nuclear masses very far from stability when applied at radioactive beam facilities like the NSCL. Such measurements are important for understanding nuclear structure far from the valley of β-stability, and provide valuable information for astrophysical model calculations of processes involving very unstable nuclides.

  10. New mass measurements of neutron rich nuclides at the NSCL.

    NASA Astrophysics Data System (ADS)

    Estrade, Alfredo; Matos, Milan; Amthor, Matthew; Bazin, Daniel; Becerril, Ana; Elliot, Thom; Gade, Alexandra; Galaviz, Daniel; Lorusso, Giuseppe; Pereira, Jorge; Portillo, Mauricio; Rogers, Andrew; Schatz, Hendrik; Shapira, Dan; Smith, Ed; Stolz, Andreas; Wallace, Mark

    2007-10-01

    A mass measurement of exotic isotopes in the region of 68Fe has been performed at the NSCL using the time-of-flight technique recently established. Experimental knowledge of the mass of very neutron rich nuclides is an important input for astrophysical applications, such as nucleosynthesis during the r-process and the evolution of matter in the crust of an accreting neutron star, where present calculations are mostly limited to using theoretical mass extrapolations. We present the details of the experimental set up, as well as preliminary results.

  11. Significance of the effect of mineral alteration of nuclide migration

    SciTech Connect

    Murakami, Takashi; Ohnuki, Toshihiko; Isobe, Hiroshi; Sato, Tsutomu; Yanase, Nobuyuki; Kimura, Hideo

    1994-12-31

    In order to clarify the effect of mineral alteration on nuclide migration, we examined the processes, mechanisms, and kinetics of chlorite weathering, and the uranium concentrations in minerals and rocks at Koongarra, Australia. The observed concentrations of uranium in rocks were compared to those calculated. The sequence of chlorite weathering may be simply expressed as a chlorite {yields} vermiculite {yields} kaolinite conversion. These minerals occur as a function of depth, which corresponds well to uranium concentrations on the meter scale. Iron minerals, closely related to the uranium redistribution, are released during the weathering. The first-order kinetic model of the weathering process suggests that the weathering rate is not constant but time-dependent. The uranium concentrations are qualitatively proportional to the extent of the weathering, the weathered part having higher uranium concentration. Uranium mainly occurs with iron minerals, and sub micron sized saleeite, a uranyl phosphate, is one of the most probable uranyl phases associated with the iron minerals. The uranium fixation mechanisms are probably saleeite microcrystal coprecipitation and sorption to the iron minerals. Our model, which describes uranium concentrations in rocks as a function of time, shows that the transition zone (a vermiculite dominant area) plays an important role in the uranium migration. We have established that weathering of chlorite has affected the redistribution of uranium for more than one million years. The present study demonstrates the significance of mineral alteration when we estimate nuclide migration for geologic time.

  12. ICoN, the Interactive Chart of Nuclides

    NASA Astrophysics Data System (ADS)

    Lee, Kevin; Mumpower, Matthew; Aprahamian, Ani

    2015-10-01

    Nuclear data is critical to research fields from medicine to astrophysics. The chart of nuclides is a more descriptive version of the periodic table that can be used to visualize nuclear properties such as half-lives and mass. We have created ICoN (simply short for Interactive Chart of Nuclides), an API which can be used to visualize theoretical and experimental datasets. This visualization is achieved by using D3 (Data Driven Documents), HTML, and CSS3 to plot the elements and color them accordingly. ICoN features many customization options that users can access that are dynamically applied to the chart without reloading the page. Users can save the customized chart they create to various formats. We have constructed these features in order to provide a unique approach for researchers to interface with nuclear data. ICoN can also be used on all electronic devices without loss of support. We report on the current progress of this project and will present a working demo that highlights each aspect of the aforementioned features. This is the first time that all available technologies are put to use to make nuclear data more accessible than ever before. This is a first and we will make it available as open source ware.

  13. Forbush decreases geomagnetic and atmospheric effects cosmogenic nuclides

    NASA Technical Reports Server (NTRS)

    Flueckiger, E. O.

    1986-01-01

    An overview and synthesis is given of recent developments that have occurred in the areas of Forbush decreases, geomagnetic and atmospheric effects, and cosmogenic nuclides. Experimental evidence has been found for substantial differences in the effects of the various types of interplanetary perturbations on cosmic rays, and for a dependence of these effects on the three-dimensional configuration of the interplanetary medium. In order to fully understand and to be able to simulate the solar cosmic ray particle access to the polar regions of the earth we need accurate models of the magnetospheric magnetic field. These models must include all major magnetospheric current systems (in particular the field aligned currents), and they should represent magnetically quiet time periods as well as different levels of geomagnetic activity. In the evolution of magnetospheric magnetic field models, cosmic ray and magnetospheric physicists should work closely together since cosmic ray measurements are a powerful additional tool in the study of the perturbed magnetosphere. In the field of cosmogenic nuclides, finally, exciting new results and developments follow in rapid succession. Thanks to new techniques and new isotopes the analysis of cosmic ray history has entered into a new dimension.

  14. Bridging the timescales between thermochronological and cosmogenic nuclide data

    NASA Astrophysics Data System (ADS)

    Glotzbach, Christoph

    2015-04-01

    Reconstructing the evolution of Earth's landscape is a key to understand its future evolution and to identify the driving forces that shape Earth's surface. Cosmogenic nuclide and thermochronological methods are routinely used to quantify Earth surface processes over 102-104 yr and 106-107 yr, respectively (e.g. Lal 1991; Reiners and Ehlers 2005; von Blanckenburg 2006). A comparison of the rates of surface processes derived from these methods is, however, hampered by the large difference in their timescales. For instance, a constant erosion rate of 0.1 mm/yr yield an apatite (U-Th)/He age of ~24 Ma and a 10Be age of ~6 ka, respectively. Analytical methods that bridge this time gap are on the way, but are not yet fully established (e.g. Herman et al. 2010). A ready to use alternative are river profiles, which record the regional uplift history over 102-107 yr (e.g. Pritchard et al. 2009). Changes in uplift are retained in knickzones that propagate with a distinct velocity upstream, and therefore the time of an uplift event can be estimated. Here I present an integrative inverse modelling approach to simultaneously reconstruct river profiles, model thermochronological and cosmogenic nuclide data and to derive robust information about landscape evolution over thousands to millions of years. An efficient inversion routine is used to solve the forward problem and find the best uplift history and erosional parameters that reproduce the observed data. I test the performance of the algorithm by inverting a synthetic dataset and a dataset from the Sila massif (Italy). Results show that even complicated uplift histories can be reliably retrieved by the combined interpretation of river profiles, thermochronological and cosmogenic nuclide data. References Gallagher, K., Brown, R. & Johnson, C. (1998): Fission track analysis and its applications to geological problems. - Annu. Rev. Earth Planet., 26: 519-572. Herman, F., Rhodes, E.J., Braun, J. & Heiniger, L. (2010): Uniform

  15. Cosmogenic nuclide dating of glaciofluvial deposits: insights from the Alps

    NASA Astrophysics Data System (ADS)

    Akcar, Naki; Ivy-Ochs, Susan; Alfimov, Vasily; Claude, Anne; Reber, Regina; Christl, Marcus; Vockenhuber, Christof; Schlunegger, Fritz; Rahn, Meinert; Dehnert, Andreas; Schlüchter, Christian

    2015-04-01

    Cosmogenic 10Be and 26Al can be employed to reconstruct the chronology of sediment layers. Accumulation of these can be used to exposure date the sediment layer as the variation of cosmogenic nuclide concentration with depth can be modeled. Decay of 10Be and 26Al in the samples from a well-defined single bed in a deposit enables the modeling of the post-burial component and the determination of the 26Al/10Be at the time of burial. The isochron-burial age can then be calculated from the initial and the measured ratios. In this study, we focus on the depth-profile and isochron-burial dating of the oldest Quaternary deposits of the Alpine Foreland. These are called Swiss Deckenschotter (cover gravels) as they build mesa-type hill tops on the Mesozoic or Cenozoic bedrock of the Swiss Alpine forelands. Deckenschotter consists of glaciofluvial gravel layers intercalated with glacial and/or overbank deposits. Although previously morphostratigraphically correlated with Günz and Mindel glaciations of Penck and Brückner, the Swiss Deckenschotter is likely much older, and their chronostratigraphy is not well constrained. In order to reconstruct the chronology of these deposits, we studied two Deckenschotter outcrops in abandoned gravel pits in Mandach (507 m a.s.l.) and Siglistorf (530 m a.s.l.) in canton Zurich. We collected four samples from Mandach for 10Be analysis and more than 30 clasts of different lithology, shape and size from a single stratigraphic horizon in Siglistorf among which we processed 19 clasts for 10Be and 26Al analysis. 10Be concentrations of the Mandach samples vary between 10000 and 30000 at/g. Based on these, we calculated a modal depth-profile age of around 1.0 Ma. Among Siglistorf samples, four did not yield successful 26Al measurements and two were unsuccessful for 10Be. Most of the samples have low nuclide concentrations, i.e. <20000 10Be at/g and <150000 26Al at/g. The 26Al/10Be ratio of eight samples was above the surface ratio of 6

  16. Cosmic-ray interactions and dating of meteorite stranding surfaces with cosmogenic nuclides

    SciTech Connect

    Reedy, R.C.

    1988-01-01

    A wide variety of products from cosmic-ray interactions have been measured in terrestrial or extraterrestrial samples. These ''cosmogenic'' products include radiation damage tracks and rare nuclides that are made by nuclear reactions. They often have been used to determine the fluxes and composition of cosmic-ray particles in the past, but they are usually used to study the history of the ''target'' (such as the time period that it was exposed to cosmic-ray particles). Products made by both the high-energy galactic cosmic rays and energetic particles emitted irregularly from the Sun have been extensively studied. Some of these cosmogenic products, especially nuclides, have been or can be applied to studies of Antarctic meteorite stranding surfaces, the ice surfaces in Antarctica where meteorites have been found. Cosmogenic nuclides studied in samples from Antarctica and reported by others elsewhere in this volume include those in meteorites, especially radionuclides used to determine terrestrial ages, and those made in situ in terrestrial rocks. Cosmogenic nuclides made in the Earth's atmosphere or brought in with cosmic dust have also been studied in polar ice, and it should also be possible to measure nuclides made in situ in ice. As an introduction to cosmogenic nuclides and their applications, cosmic rays and their interactions will be presented below and production systematics of cosmogenic nuclides in these various media will be discussed later. 20 refs., 2 tabs.

  17. Nuclide identification algorithm based on K-L transform and neural networks

    NASA Astrophysics Data System (ADS)

    Chen, Liang; Wei, Yi-Xiang

    2009-01-01

    Traditional spectrum analysis algorithm based on peak search is hard to deal with complex overlapped peaks, especially in bad resolution and high background conditions. This paper described a new nuclide identification method based on the Karhunen-Loeve transform (K-L transform) and artificial neural networks. By the K-L transform and feature extraction, the nuclide gamma spectrum was compacted. The K-L transform coefficients were used as the neural network's input. The linear associative memory and ADALINE were discussed. Lots of experiments and tests showed that the method was credible and practical, especially suitable for fast nuclide identification.

  18. Inventory simulation tools: Separating nuclide contributions to radiological quantities

    NASA Astrophysics Data System (ADS)

    Gilbert, Mark R.; Fleming, Michael; Sublet, Jean-Christophe

    2017-09-01

    The activation response of a material is a primary factor considered when evaluating its suitability for a nuclear application. Various radiological quantities, such as total (becquerel) activity, decay heat, and γ dose, can be readily predicted via inventory simulations, which numerically evolve in time the composition of a material under exposure to neutron irradiation. However, the resulting data sets can be very complex, often necessarily resulting in an over-simplification of the results - most commonly by just considering total response metrics. A number of different techniques for disseminating more completely the vast amount of data output from, in particular, the FISPACT-II inventory code system, including importance diagrams, nuclide maps, and primary knock-on atom (PKA) spectra, have been developed and used in scoping studies to produce database reports for the periodic table of elements. This paper introduces the latest addition to this arsenal - standardised and automated plotting of the time evolution in a radiological quantity for a given material separated by contributions from dominant radionuclides. Examples for relevant materials under predicted fusion reactor conditions, and for bench-marking studies against decay-heat measurements, demonstrate the usefulness and power of these radionuclide-separated activation plots. Note to the reader: the pdf file has been changed on September 22, 2017.

  19. Modified microspheres for cleaning liquid wastes from radioactive nuclides

    SciTech Connect

    Danilin, Lev; Drozhzhin, Valery

    2007-07-01

    An effective solution of nuclear industry problems related to deactivation of technological and natural waters polluted with toxic and radioactive elements is the development of inorganic sorbents capable of not only withdrawing radioactive nuclides, but also of providing their subsequent conservation under conditions of long-term storage. A successful technical approach to creation of sorbents can be the use of hollow aluminosilicate microspheres. Such microspheres are formed from mineral additives during coal burning in furnaces of boiler units of electric power stations. Despite some reduction in exchange capacity per a mass unit of sorbents the latter have high kinetic characteristics that makes it possible to carry out the sorption process both in static and dynamic modes. Taking into account large industrial resources of microspheres as by-products of electric power stations, a comparative simplicity of the modification process, as well as good kinetic and capacitor characteristics, this class of sorbents can be considered promising enough for solving the problems of cleaning liquid radioactive wastes of various pollution levels. (authors)

  20. Production and Recoil Loss of Cosmogenic Nuclides in Presolar Grains

    NASA Astrophysics Data System (ADS)

    Trappitsch, Reto; Leya, Ingo

    2016-05-01

    Presolar grains are small particles that condensed in the vicinity of dying stars. Some of these grains survived the voyage through the interstellar medium (ISM) and were incorporated into meteorite parent bodies at the formation of the Solar System. An important question is when these stellar processes happened, i.e., how long presolar grains were drifting through the ISM. While conventional radiometric dating of such small grains is very difficult, presolar grains are irradiated with galactic cosmic rays (GCRs) in the ISM, which induce the production of cosmogenic nuclides. This opens the possibility to determine cosmic-ray exposure (CRE) ages, i.e., how long presolar grains were irradiated in the ISM. Here, we present a new model for the production and loss of cosmogenic 3He, 6,7Li, and 21,22Ne in presolar SiC grains. The cosmogenic production rates are calculated using a state-of-the-art nuclear cross-section database and a GCR spectrum in the ISM consistent with recent Voyager data. Our findings are that previously measured 3He and 21Ne CRE ages agree within the (sometimes large) 2σ uncertainties and that the CRE ages for most presolar grains are smaller than the predicted survival times. The obtained results are relatively robust since interferences from implanted low-energy GCRs into the presolar SiC grains and/or from cosmogenic production within the meteoroid can be neglected.

  1. A new paleoaltimeter using multiple radioactive cosmogenic nuclides

    NASA Astrophysics Data System (ADS)

    Blard, Pierre-Henri; Lupker, Maarten; Rousseau, Moïse

    2017-04-01

    Determining absolute paleoaltitudes over geological timescales is one of the most challenging issues in Earth Sciences. We present here the theoretical basis of a new paleoaltimetric approach, based on the analysis of at least two cosmogenic nuclides with different radioactive decay, that have been produced in paleo-exposed surfaces. Applying this method to the existing 21Ne-10Be-26Al datasets in the dry Andes shows a very good agreement between the computed and the sampling elevations. Limitations and uncertainties of our new approach are evaluated using several numerical simulations. In many cases, the uncertainty at the 1-sigma level will be lower than 1000 m. The two main advantages of this method are i) the computed altitude is almost insensitive to the impact of erosion and ii) it does not require an independent determination of the duration of the paleo-exposure. However it has the inconvenient to require long paleoexposure (> 500 ka), which can be difficult to find in fast eroding mountainous environments.

  2. International program to improve decay data for transactinium nuclides

    NASA Astrophysics Data System (ADS)

    Helmer, R. G.; Reich, C. W.

    To help meet an identified need for precise decay data, in 1977 an international coordinated research program (CRP) to measure and evaluate half-lives and gamma (-) and alpha (-) emission probabilities for selected transactinium nuclides of importance for reactor technology was organized. The CRP goals were: (1) to determine a list of data that needed improvement, (2) to encourage new measurements, and (3) to evaluate the available data. All three phases of this work are now complete. Participation in this effort involved the measurement of gamma-ray emission probabilities for sup 232, 233, 235 U, sup 238, 239, 240. 241 Pu, (229)Th and (233)Pa, as well as participating in the data evaluation. The gamma-emission probabilities were determined from the measurement of gamma-emission rates with the goal of obtaining uncertainties of less than or equal to 1%. Measurements were made on calibrated Ge detectors. These calibrations were done by standard methods, generally involving measurements at approx. 60 gamma-ray energies from 14 to 2700 keV. The efficiency-calibration functions were assigned uncertainties ranging from 2% below 50 keV to 0.50% from 400 to 1400 keV. The determination of the decay rates of the various sources involved several techniques.

  3. Recommended Partition Coefficient (Kd) Values for Nuclide Partitioning in the Presence of Cellulose Degradation Products

    SciTech Connect

    Serkiz, S.M.

    2001-02-23

    This report documents the data analysis of the results of the described laboratory studies in order to recommend Kd values for use in Performance Assessment modeling of nuclide transport in the presence of CDP.

  4. Phase II Nuclide Partition Laboratory Study Influence of Cellulose Degradation Products on the Transport of Nuclides from SRS Shallow Land Burial Facilities

    SciTech Connect

    Serkiz, S.M.

    1999-10-04

    Degradation products of cellulosic materials (e.g., paper and wood products) can significantly influence the subsurface transport of metals and radionuclides. Codisposal of radionuclides with cellulosic materials in the E-Area slit trenches at the Savannah River Site (SRS) is, therefore, expected to influence nuclide fate and transport in the subsurface. Due to the complexities of these systems and the scarcity of site-specific data, the effects of cellulose waste loading and its subsequent influence on nuclide transport are not well established.

  5. Addressing nuclides not in the CAP88-PC Version-3 library.

    PubMed

    McNaughton, Michael; Brock, Burgandy; Eisele, William; Fuehne, David; Green, Andrew; Whicker, Jeffrey

    2013-08-01

    Versions of the computer program, CAP88, are widely used to calculate the radiological doses from radionuclides emitted into the air. CAP88-PC Version-3 includes an extensive library of radionuclides, but there are many more that are not included. Surrogates are often used to substitute for nuclides not in the library, though the results are usually overestimates. This paper addresses nuclides that are not in the library and describes methods to obtain more accurate results.

  6. Investigation of Naturally Occurring Radio Nuclides in Shir-kuh Granites

    SciTech Connect

    Mazarei, Mohammad Mehdi; Zarei, Mojtaba

    2011-12-26

    One of the principle natural radiation resources is Granite which can be dangerous for human because of its radiations. Based on this fact, in this research we attempt to specify the activity amount of these natural radio nuclides, existing in Shir-kuh Granite of Yazd state. To specify the activity amount of this natural radio nuclides, it has been applied the measurement method of Gamma spectroscopy using high purity Germanium (HPGe) detector.

  7. Production Rates of Cosmogenic Nuclides in the Knyahinya L-Chondrite

    NASA Technical Reports Server (NTRS)

    Kim, K. J.; Reedy, R. C.

    2004-01-01

    The production rates of spallogenic radionuclides and stable isotopes in the L-chondrite Knyahinya were investigated using the MCNPX code. Numerous cosmogenic nuclides had been measured in many Knyahinya samples. The pre-atmospheric size and sample locations of Knyahinya are well known, thus Knyahinya is a good test case for cosmogenic-nuclide production-rate calculations. Our calculated profiles were compared to the measurements to determine effective proton fluxes.

  8. Measurements of Cosmogenic Nuclides in and their Significance for Samples Returned from Asteroids

    NASA Technical Reports Server (NTRS)

    Nishiizumi, K.; Herzog, G. F.; Reedy, R. C.

    2000-01-01

    Nuclear interactions of cosmic rays with matter produce cosmogenic nuclides (CNs). Ever since they were first measured nearly 50 years ago, cosmogenic nuclides have been used to infer the irradiation histories of terrestrial and extraterrestrial materials. Here we call for an extension of such measurements to samples returned from an asteroidal surface. The information gained in this way will be important for elucidating the evolution of the asteroidal surface. Additional information is contained in the original extended abstract.

  9. Global sediment production from in-situ cosmogenic nuclides in large river basins

    NASA Astrophysics Data System (ADS)

    Haedke, H.; Wittmann, H.; von Blanckenburg, F.; Gaillardet, J.

    2016-12-01

    The worlds 30 largest rivers represent half of the total runoff to the ocean and thus integrate the fluxes of Earth surface weathering and erosion over a large portion of global tectonic, geomorphic, and climatic zones. In-situ produced cosmogenic nuclides (10Be, 26Al) in detrital quartz sand can be used to constrain the mean millennial-scale denudation of these large basins. Yet cosmogenic nuclides have mostly been applied to small and intermediate size basins of significant relief. One reason is that in these settings, lowland sediment storage and burial are short compared to the half life of the nuclide (e.g. 1.4 Myr for 10Be). However, if sediment storage is long compared to the half-life, paired nuclides (e.g. 26Al/10Be), through their differential decay, allow to assess the duration of sediment transfer and burial ages from source to sink[1]. Here we present a new dataset of cosmogenic nuclides from 60 large rivers that integrate over 30% of Earth's terrestrial surface. 26Al/10Be ratios of around 6 to 7.5 for most rivers reveal burial durations shorter than the nuclides' decay time scales, indicating high source-sink connectivity. In slowly-eroding basins such as the tectonically quiescent Australian Murray-Darling or the central African Okavango and Congo rivers, 26Al/10Be ratios of <6 indicate decay of nuclide concentrations. Such low nuclide ratios evolve during Myr-scale sediment burial during slow source to sink transfer. We converted denudation rates to sediment fluxes by estimating their actively eroding source areas. Extrapolating these millennial-scale sediment fluxes to global source areas provides an estimate of the global sediment flux. The comparison with estimates of modern sediment fluxes from river load gauging offers to deciphering the controls of sediment generation versus sediment transport across large basins. [1] Wittmann and von Blanckenburg (2016), Earth Science Reviews, 159,118-141.

  10. Using cosmogenic nuclides from amalgamated talus cobbles to assess alpine erosion in the Teton Range

    NASA Astrophysics Data System (ADS)

    Tranel, L. M.

    2014-12-01

    Measuring spatial patterns and rates of erosion in alpine landscapes is challenging because locations are steep and remote, and hillslope processes including rockfalls, avalanches and landslides are stochastic. This study evaluates how variability between quantitative erosion rates and surface ages and qualitative weathering features on talus deposits may influence interpretations of the spatial distribution of hillslope erosion in the Teton Range. I use cosmogenic nuclide concentrations to estimate erosion rates and surface ages of bedrock and talus deposits. I then compare these cosmogenic nuclide results to talus volumetric estimates of erosion rates. I also compare the quantitative estimates of surface ages and erosion to qualitative weathering observations on talus cobbles. The resulting erosion rates from cosmogenic nuclides are slower than rates estimated from talus volumes, however, both methods produced the same pattern of erosion. The fastest and slowest cosmogenic nuclide and volumetric erosion rates were associated with the same fans. Exposure ages of talus surfaces decrease as elevation of the fans increase. Qualitative observations of weathering on cobble surfaces were not reliable to predict the relative rates of erosion on the talus fans. Using amalgamated samples from hillslope deposits adjacent to steep sided canyons for cosmogenic nuclide analysis has high uncertainty when finding accurate erosion rates or exposure ages due to complicated shielding on steeply sloping walls. The similar patterns of rapid or slow erosion rates, however, suggest that cosmogenic nuclides or volume estimates are both reasonable methods to understand relative timing of hillslope events, even if the absolute age or erosion rate cannot be determined.

  11. (1) Selective separation and solidification of radioactive nuclides by zeolites

    NASA Astrophysics Data System (ADS)

    Mimura, Hitoshi; Sato, Nobuaki; Kirishima, Akira

    Massive tsunami generated by the Great East Japan Earthquake attacked the Fukushima Daiichi Nuclear Power Plant and caused the nuclear accident of level 7 to overturn the safety myth of the nuclear power generation. The domestic worst accident does not yet reach the convergence, and many inhabitants around the power plant are forced to double pains of earthquake disaster and nuclear accident. Large amounts of high-activity-level water over 200,000 tons are accumulated on the basement floor of each turbine building, which is a serious obstacle to take measures for the nuclear accident. For the decontamination of high-activity-level water containing seawater, the inorganic ion-exchangers having high selectivity are effective especially for the selective removal of radioactive Cs. On the other hand, radioactive Cs and I released into the atmosphere from the power plant spread widely around Fukushima prefecture, and the decontamination of rainwater and soil become the urgent problem. At present, passing about four months after nuclear accident, the radioactive nuclides of 137Cs and 134Cs are mainly contained in the high-activity-level water and the selective adsorbents for radioactive Cs play an important part in the decontamination. Since the construction of original decontamination system is an urgent necessity, selective separation methods using inorganic ion-exchangers are greatly expected. From the viewpoint of cost efficiency and high Cs-selectivity, natural zeolites are effective for the decontamination of radioactive Cs. This special issue deals with the selective separation and solidification of radioactive Cs and Sr using zeolites.

  12. International program to improve decay data for transactinium nuclides

    NASA Astrophysics Data System (ADS)

    Helmer, R. G.; Reich, C. W.

    1986-01-01

    To help meet an identified need for precise decay data, in 1977 the IAEA organized an international Coordinated Research Program (CRP) to measure and evaluate half-lives and γ- and α-emission probabilities for selected transactinium nuclides of importance for reactor technology. The CRP goals were (1) to determine a list of data that needed improvement, (2) to encourage new measurements, and (3) to evaluate the available data. All three phases of this work are now complete. Our participation in this effort has involved the measurement of γ-ray emission probabilities for 232,233,235U, 238,239,240,241Pu, 229Th and 233Pa, as well as participating in the data evaluation. The γ-emission probabilities were determined from the measurement of γ-emission rates with the goal of obtaining uncertainties of ≤ 1%. γ-measurements were made on calibrated Ge detectors. These calibrations were done by standard methods, generally involving measurements at ˜ 60 γ-ray energies from 14 to 2700 keV. The efficiency-calibration functions were assigned uncertainties ranging from 2% below 50 keV to 0.50% from 400 to 1400 keV. The determination of the decay rates of the various sources involved several techniques. The 238Pu, 239Pu and 240Pu samples were calibrated by gross α-emission-rate measurements at NBS. The 235U sample was taken from an NBS-calibrated spike solution. The 241Pu and 233U samples were calibrated by isotope-dilution mass spectrometry based on spikes of the calibrated 239Pu, 240Pu and 235U materials. Some of our results are given, together with a comparison of some present and previous results.

  13. Mass Determination of Two-Proton Radioactive Nuclides

    SciTech Connect

    Miernik, Krzysztof A

    2012-01-01

    The masses of heavy two-proton emitters (45Fe, 48Ni and 54Zn) are calculated, basing on experimentally measured two-proton decay energies. The results are compared with theoretical predictions and extrapolations.

  14. Chemistry of heavy ion reactions

    SciTech Connect

    Hoffman, D.C.

    1988-10-01

    The use of heavy ions to induce nuclear reactions was reported as early as 1950. Since that time it has been one of the most active areas of nuclear research. Intense beams of ions as heavy as uranium with energies high enough to overcome the Coulomb barriers of even the heaviest elements are available. The wide variety of possible reactions gives rise to a multitude of products which have been studied by many ingenious chemical and physical techniques. Chemical techniques have been of special value for the separation and unequivocal identification of low yield species from the plethora of other nuclides present. Heavy ion reactions have been essential for the production of the trans-Md elements and a host of new isotopes. The systematics of compound nucleus reactions, transfer reactions, and deeply inelastic reactions have been elucidated using chemical techniques. A review of the variety of chemical procedures and techniques which have been developed for the study of heavy ion reactions and their products is given. Determination of the chemical properties of the trans-Md elements, which are very short-lived and can only be produced an ''atom-at-a-time'' via heavy ion reactions, is discussed. 53 refs., 19 figs.

  15. Cosmogenic nuclides application on French Mediterranean shore platform development

    NASA Astrophysics Data System (ADS)

    Giuliano, Jérémy; Lebourg, Thomas; Godard, Vincent; Dewez, Thomas; Braucher, Régis; Bourlès, Didier; Marçot, Nathalie

    2014-05-01

    Rocky shorelines are among the most common elements of the world's littoral zone, and the potential effects of rising sea level on the ever increasing populations require a better understanding of their dynamics. The sinuosity and heterogeneity of the shoreline morphology at large and intermediate wavelengths (1-100 km) results from their constant evolution under the combined influence of marine and continental forcings. This macro-scale organization is the expression of the action of elementary erosion processes acting at shorter wavelengths (<1 km) which lead to the development of shore platforms by landward retreat of cliff edges. Modern analytical techniques (laser-scaning, micro-erosion meters, aerial surveys) constitute appropriate methods to identify and quantify processes of cliff retreat to 1-100 yrs time-scales. But over this time frame, shore platform development appears imperceptible. Precise knowledge of long-term erosion rates are needed to understand rocky shore evolution, and develop quantitative modeling of platform development. Rocky coasts constitute a Quaternary sea level evolution archive that is partly preserved and progressively destroyed. One major challenges is to determine the degree to which coast morphologies are (i) contemporary, (ii) or ancient features inherited, (iii) or partly inherited from Quaternary interglacial stages. In order to fill the lack of long term coast morphodynamic data, we use cosmogenic nuclides (36Cl) to study abrasion surfaces carved in carbonates lithologies along the French Mediterranean coast, in a microtidal environment (Côte Bleue, West of Marseille). 36Cl concentration heritage influences strongly our interpretations in terms of age and denudation of the surfaces. We propose to constrain heritage in sampling oldest relic marine surfaces at 10m of altitude, and along recent cliff scarp. 36Cl concentrations show that the lowest platforms near sea level are contemporary and the highest ones (8-14 m above sea

  16. Production profiles of nuclides by galactic-cosmic-ray particles in small meteoroids

    NASA Astrophysics Data System (ADS)

    Reedy, R. C.; Masarik, J.

    Many of the meteorites found in cold and hot deserts are small, and many were small bodies in space. Production of cosmic-ray-produced (cosmogenic) nuclides in small meteoroids is expected to be different than that in the larger meteoroids typically studied, with lower levels of nuclide production by galactic-cosmic-ray (GCR) particles and possibly significant production by solar-cosmic-ray (SCR) protons. Motivated by the cosmogenic-nuclide measurements for the very small Salem meteorite and for cosmic spherules, which show high levels of SCR production, we have reported earlier nuclide production rates by SCR protons in small objects in space. The GCR production rates reported for small meteoroids have not been tested and were expected to be poor for meteoroids with radii less than 40 g/cm2 because of the very simple nature of that semi-empirical model (only one free parameter) and because the mix of neutrons and protons is different (relatively more protons) than that in the model, which was based on larger objects. Thus we have calculated produciton rates for nuclides mad by GCR particles in small objects with a physical model that is much better suited for unusual targets.

  17. A model for GCR-particle fluxes in stony meteorites and production rates of cosmogenic nuclides

    NASA Astrophysics Data System (ADS)

    Reedy, R. C.

    1985-02-01

    A model is presented for the differential fluxes of galactic-cosmic-ray (GCR) particles with energies above 1 MeV inside any spherical stony meteorite as a function of the meteorite's radius and the sample's depth. This model is based on the Reedy-Arnold equations for the energy-dependent fluxes of GCR particles in the moon and is an extension of flux parameters that were derived for several meteorites of various sizes. This flux is used to calculate the production rates of many cosmogenic nuclides as a function of radius and depth. The peak production rates for most nuclides made by the reactions and energetic GCR particles occur near the centers of meteorites with radii of 40 to 70 g/cm (2). Although the model has some limitations, it reproduces well the basic trends for the depth-dependent production of cosmogenic nuclides in stony meteorites of various radii. These production profiles agree fairly well with measurments of cosmogenic nuclides in meteorites. Some of these production profiles are different than those calculated by others. The chemical dependence of the production rates for several nuclides varies with size and depth.

  18. Model for GCR-particle fluxes in stony meteorites and production rates of cosmogenic nuclides

    SciTech Connect

    Reedy, R.C.

    1984-01-01

    A model is presented for the differential fluxes of galactic-cosmic-ray (GCR) particles with energies above 1 MeV inside any spherical stony meteorite as a function of the meteorite's radius and the sample's depth. This model is based on the Reedy-Arnold equations for the energy-dependent fluxes of GCR particles in the moon and is an extension of flux parameters that were derived for several meteorites of various sizes. This flux is used to calculate the production rates of many cosmogenic nuclides as a function of radius and depth. The peak production rates for most nuclides made by the reactions of energetic GCR particles occur near the centers of meteorites with radii of 40 to 70 g cm/sup -2/. Although the model has some limitations, it reproduces well the basic trends for the depth-dependent production of cosmogenic nuclides in stony meteorites of various radii. These production profiles agree fairly well with measurements of cosmogenic nuclides in meteorites. Some of these production profiles are different than those calculated by others. The chemical dependence of the production rates for several nuclides varies with size and depth. 25 references, 8 figures.

  19. Simulation of the production rates of cosmogenic nuclides on the Moon based on Geant4

    NASA Astrophysics Data System (ADS)

    Li, Yong; Zhang, Xiaoping; Dong, Wudong; Ren, Zhongzhou; Dong, Tiekuang; Xu, Aoao

    2017-02-01

    A numerical simulation model is built to simulate the production of cosmogenic nuclides based on Geant4 (GEometry ANd Tracking). Some modifications have been made for cross sections in Geant4 using the experimental data or the other proper model and the contributions of all secondary particles caused by cosmic rays are included in our simulation model. Our simulation results suggest a substantial contribution of the secondary charged pions to the production rates of 10Be and 14C, as high as 21.04% for 10Be and 21.36% for 14C, respectively. Within one set of self-consistent parameters, the simulation results of the production rates of the cosmogenic nuclides, 53Mn, 36Cl, 41Ca, 26Al, 10Be, and 14C, agree well with the measured data from Apollo 15 drill core. This model provides users a validated approach to study the production of cosmogenic nuclides on the planet surface and in the meteorites.

  20. Paleo-erosion rates versus paleo-erosion processes from cosmogenic nuclide concentrations in sedimentary archives

    NASA Astrophysics Data System (ADS)

    Schildgen, Taylor; Garcin, Yannick; Savi, Sara; Tofelde, Stefanie; Wittmann, Hella; Strecker, Manfred

    2017-04-01

    Paleo-erosion rates derived from cosmogenic nuclide concentrations in sedimentary archives are commonly observed to differ from modern rates, in some cases by several orders of magnitude. However, the meaning of these rates can be unclear when we consider the averaging timescale (and presumed lag) of the cosmogenic nuclide technique in recording erosion rates, grain-size dependencies in nuclide concentrations, and assumptions inherent to the detrital approach. These issues can complicate our ability to interpret landscape response to past climate change from cosmogenic nuclides. In general, the cosmogenic nuclide concentration in sediment is inversely related to the catchment mean erosion rate. However, several studies, including ours from the Central Andes, have suggested that low nuclide concentrations from fill terrace sediment coupled with a strong grain-size dependence in nuclide concentrations point to a greater importance of landslide activity in the past. In such settings, cosmogenic nuclide concentrations may provide clear signals of changes in erosion processes, but are difficult to interpret in terms of changes in erosion rates. These complications may be reduced in low-relief catchments, where landsliding is unlikely. Such is the case for the semi-arid Baragoi catchment of East Africa, which was affected by a wetter climate during the African Humid Period (ca. 15-6 cal. kyr BP). From that time period, we calculate paleo-erosion rates from cosmogenic nuclides within deltaic sediments that are up to 7x faster than modern rates. Moreover, erosion rates rise rapidly near the onset of wetter climate conditions, then drop to near-modern rates well before the return to semi-arid conditions. Given that the averaging timescale of our samples is 8 to 46 kyr, to match the rapid observed rise in erosion rates with a 1D model of cosmogenic nuclide accumulation requires an increase in erosion rates several hundred times higher than the initial (pre-delta formation

  1. Measurements of nuclide yields in neutron-induced fission of natural uranium for SPIRAL2

    NASA Astrophysics Data System (ADS)

    Lhersonneau, G.; Malkiewicz, T.; Trzaska, W. H.

    2014-01-01

    Cross-sections for nuclide production in fast-neutron induced fission of natural uranium are part of the input for predictions of yields of neutron-rich nuclides obtainable at Radioactive Ion Beam facilities. We first describe the neutron spectra produced according to the scheme once envisaged for SPES (protons on an enriched 13C target) and the one adopted for SPIRAL2 (deuterons on natural carbon), which both have been measured at JYFL. We then present the measurements of Z-splits in isobaric chains performed at IGISOL. When coupled with the fission cross-section and A-splits for the relevant neutron spectrum, they allow estimates of nuclide cross-sections. It looks that calculations, even those based on modern libraries, are too optimistic by about a factor of two.

  2. Optical model methods of predicting nuclide production from spallation reactions.

    PubMed

    Ramsey, C R; Townsend, L W; Tripathi, R K; Cucinotta, F A

    1998-02-01

    Quantum mechanical optical model methods for calculating isotope production cross sections from the spallation of heavy nuclei by high-energy protons are developed from a modified abrasion-ablation collision formalism. The abrasion step is treated quantum-mechanically as a knockout process which leaves the residual prefragment nucleus in an excited state. In ablation the prefragment deexcites to produce the final fragment. The excitation energies of the prefragments are estimated from a combination of liquid drop and frictional-spectator interaction considerations. Estimates of elemental and isotopic production cross sections are in good agreement with recently published cross section measurements.

  3. Neogene basin infilling from cosmogenic nuclides (10Be and 21Ne) in Atacama, Chile

    NASA Astrophysics Data System (ADS)

    Sanchez, Caroline; Regard, Vincent; Carretier, Sébastien; Riquelme, Rodrigo; Blard, Pierre-Henri; Campos, Eduardo; Brichau, Stéphanie; Lupker, Marteen; Hérail, Gérard

    2017-04-01

    In the hyperarid Atacama Desert, northern Chile, Neogene sediments host copper rich layers (exotic supergene mineralization). Current mines are excavated into relatively thin (<200-300 m) Neogene basins whose infilling chronology is poorly constrained. We took advantage of one of these mining pits, and sampled for 10Be and 21Ne cosmogenic nuclide dosing. These cosmogenic nuclides help constraining the infilling chronology. Indeed, basin sediments were deposited with a cosmogenic nuclide content acquired on hillslopes. Then within the basin, cosmogenic nuclide concentrations evolved through the competing production (quickly decreasing with depth) and disintegration (not for 21Ne). Sampling depths are at ˜100 m and at ˜50 m below the desert surface. First, 21Ne gives lower boundaries for upstream erosion rates or local sedimentation rate. These bounds are between 2 and 10 m/Ma, which is quite important for the area. The ratio between the two cosmogenic nuclides indicate a maximum burial age of 12 Ma (minimal erosion rate of 15 m/Ma) and is surprisingly similar from bottom to top, indicating a probable rapid infilling. We finally processed a Monte-Carlo inversion. This inversion helps taking into account the post-deposition muonic production of cosmogenic nuclides. Inversion results is dependent on the muonic production scheme. Interestingly, the similarity in concentrations from bottom to top pleads for quite low production at depth. Our data finally indicates a quick infilling between 12.5 and 10 Ma BP accounting for ˜100 m of deposition (minimum sedimentation rate of 40 m/Ma).

  4. A study of separation and solidification of group II nuclides in waste salt delivered from the pyrochemical process of used nuclear fuel

    NASA Astrophysics Data System (ADS)

    Eun, H. C.; Choi, J. H.; Kim, N. Y.; Lee, T. K.; Han, S. Y.; Jang, S. A.; Kim, T. J.; Park, H. S.; Ahn, D. H.

    2017-08-01

    If group II nuclides, which contain high heat-generative elements, in waste salt are fabricated into a waste form rich in group II nuclides, the waste form can be used in radionuclide thermoelectric generator applications. For this reason, the separation of group II nuclides in salt (LiCl, LiCl-KCl) was conducted, after which a waste form rich in them was fabricated. In this study, group II nuclide chlorides in salt were effectively separated into a carbonate or oxychloride form, and the separated nuclides were successfully fabricated into a homogenous and stable glass waste form with high contents (45-50 wt%) of these nuclides.

  5. Accelerator experiments on the contribution of secondary particles to the production of cosmogenic nuclides in meteorites

    NASA Technical Reports Server (NTRS)

    Dragovitsch, P.; Englert, P.

    1985-01-01

    Through the interaction of galactic cosmic particle radiation (GCR) a wide variety of cosmogenic nuclides is produced in meteorites. They provide historical information about the cosmic radiation and the bombarded meteorites. An important way to understand the production mechanisms of cosmogenic nuclides in meteorites is to gather information about the depth and size dependence of the build-up of Galactic Rays Cosmic-secondary particles within meteorites of different sizes and chemical compositions. Simulation experiments with meteorite models offer an alternative to direct observation providing a data basis to describe the development and action of the secondary cascade induced by the GCR in meteorites.

  6. Applications of in situ cosmogenic nuclides in the geologic site characterization of Yucca Mountain, Nevada

    SciTech Connect

    Gosse, J.C.; Harrington, C.D.; Whitney, J.W.

    1995-12-31

    The gradual buildup of rare isotopes from interactions between cosmic rays and atoms in an exposed rock provides a new method of directly determining the exposure age of rock surfaces. The cosmogenic nuclide method can also provide constraints on erosion rates and the length of time surface exposure was interrupted by burial. Numerous successful applications of the technique have been imperative to the complete surface geologic characterization of Yucca Mountain, Nevada, a potential high level nuclear waste repository. In this short paper, we summarize the cosmogenic nuclide method and describe with examples some the utility of the technique in geologic site characterization. We report preliminary results from our ongoing work at Yucca Mountain.

  7. Apparatus and method for quantitatively evaluating total fissile and total fertile nuclide content in samples

    DOEpatents

    Caldwell, John T.; Kunz, Walter E.; Cates, Michael R.; Franks, Larry A.

    1985-01-01

    Simultaneous photon and neutron interrogation of samples for the quantitative determination of total fissile nuclide and total fertile nuclide material present is made possible by the use of an electron accelerator. Prompt and delayed neutrons produced from resulting induced fissions are counted using a single detection system and allow the resolution of the contributions from each interrogating flux leading in turn to the quantitative determination sought. Detection limits for .sup.239 Pu are estimated to be about 3 mg using prompt fission neutrons and about 6 mg using delayed neutrons.

  8. Reprocessing system with nuclide separation based on chromatography in hydrochloric acid solution

    SciTech Connect

    Suzuki, Tatsuya; Tachibana, Yu; Koyama, Shi-ichi

    2013-07-01

    We have proposed the reprocessing system with nuclide separation processes based on the chromatographic technique in the hydrochloric acid solution system. Our proposed system consists of the dissolution process, the reprocessing process, the minor actinide separation process, and nuclide separation processes. In the reprocessing and separation processes, the pyridine resin is used as a main separation media. It was confirmed that the dissolution in the hydrochloric acid solution is easily achieved by the plasma voloxidation and by the addition of oxygen peroxide into the hydrochloric acid solution.

  9. Advanced short-lived nuclide NAA with application in the life sciences.

    PubMed

    Papadopoulos, N N; Tsagas, N F

    1994-01-01

    A new technique for short-lived nuclide activation analysis has been developed that compensates the rapid radioactive decay during the counting period by simultaneous approach of the sample holder to the detector with a mechanical device, permitting prolongation of the counting time and reduction of the required complementary cyclic activation to avoid sample container damage. The operation of the analytical system is automated by a programmable logic controller (PLC). This improvement of short-lived nuclide activation analysis, providing a high throughput, is important in biological and environmental research, where often a large number of samples has to be analyzed for sufficient sampling statistics.

  10. Using U/Th Series Nuclide Systematics for Modelling Subsurface Radionuclide Transport

    NASA Astrophysics Data System (ADS)

    Porcelli, D.; Strekopytov, S.; Shaw, S.; Hilton, D.

    2007-05-01

    U- and Th- series nuclides have provided essential tools for studying weathering and subsurface element transport processes. The radionuclides U, Th, Ra, Rn, and Pb have a range of half-lives and contrasting chemical behaviours, and their distribution between subsurface solids and water can be used to quantify rates of soil formation, chemical and mechanical weathering of watersheds, and potentially, subsurface water flow rates. Decay systematics clearly connect the different isotopes, although transfer between different phases and through subsurface systems are generally defined through a series of assumptions that have not been experimentally substantiated. Modification of these assumptions may have significant effects on the choice of models and the conclusions of U/Th series studies. Two key areas of uncertainty are: Nuclide inputs. Comparing the different isotopes requires relating the input rates from recoil and weathering. The common assumption is that nuclides are released at similar rates by recoil and congruently by weathering. Various theories have been proposed for preferential release of Rn and leaching of radionuclides, although such effects, as well as possible radionuclide fractionation during weathering release, have not been substantiated. Surface interaction mechanisms. It is generally assumed that radionuclides are removed from water onto surfaces only by reversible adsorption. However, coprecipitation, incorporation into aging secondary mineral structures, and different binding mechanisms can inhibit isotope exchange with nuclides in solution. Data from the unconfined Mojave River Basin aquifer, with a reasonably well-defined flow pattern and groundwater ages of up to ~40,000 years illustrates the response of the U/Th series nuclides to extended water- rock interaction. Measurements of 222Rn find relatively uniform recoil rates throughout the aquifer. If this rate is applied to other daughter nuclides, then the rate of 234Th release can be

  11. Residual Nuclide Production by Proton-Induced Reactions on Uranium for Energies between 20 and 70 MeV

    SciTech Connect

    Uosif, M.A.M.; Michel, R.; Herpers, U.; Kubik, P.-W.; Duijvestijn, M.; Koning, A.

    2005-05-24

    Within the HINDAS project, proton-irradiation experiments were performed at the injector cyclotron of the Paul Scherrer Institute at Villigen/Switzerland in order to investigate the production of residual nuclides from natural uranium. The stacked-foil technique was used to cover proton energies between 20 MeV and 70 MeV. Copper targets were used for monitoring the proton beam using the reaction 65Cu (p,n)65Zn. Residual radionuclides were measured by off-line {gamma}-spectrometry. Excitation functions were obtained for the production of 91Y, 95Zr, 95mNb, 99Mo, 103Ru, 112Pd, 115Cd, 124Sb, 126Sb, 127Sb, 132Te, 131I, 134Cs, 136Cs, 137Cs, 140Ba, 141Ce, 144Ce, 147Nd, and 238Np. The experimental data are compared to the sparse results of earlier measurements and with theoretical excitation functions calculated by the newly developed TALYS code. Good agreement between theory and experiment was obtained for product masses up to 115. For higher-mass fission products and for 238Np, there are still systematic deviations between theory and experiment. These deviations are discussed as deficits of the fission model in the heavy part of the fission product distribution.

  12. Residual Nuclide Production by Proton-Induced Reactions on Uranium for Energies between 20 and 70 MeV

    NASA Astrophysics Data System (ADS)

    Uosif, M. A. M.; Michel, R.; Herpers, U.; Kubik, P.-W.; Duijvestijn, M.; Koning, A.

    2005-05-01

    Within the HINDAS project, proton-irradiation experiments were performed at the injector cyclotron of the Paul Scherrer Institute at Villigen/Switzerland in order to investigate the production of residual nuclides from natural uranium. The stacked-foil technique was used to cover proton energies between 20 MeV and 70 MeV. Copper targets were used for monitoring the proton beam using the reaction 65Cu (p,n)65Zn. Residual radionuclides were measured by off-line γ-spectrometry. Excitation functions were obtained for the production of 91Y, 95Zr, 95mNb, 99Mo, 103Ru, 112Pd, 115Cd, 124Sb, 126Sb, 127Sb, 132Te, 131I, 134Cs, 136Cs, 137Cs, 140Ba, 141Ce, 144Ce, 147Nd, and 238Np. The experimental data are compared to the sparse results of earlier measurements and with theoretical excitation functions calculated by the newly developed TALYS code. Good agreement between theory and experiment was obtained for product masses up to 115. For higher-mass fission products and for 238Np, there are still systematic deviations between theory and experiment. These deviations are discussed as deficits of the fission model in the heavy part of the fission product distribution.

  13. Observation of the 3n Evaporation Channel in the Complete Hot-Fusion Reaction {sup 26}Mg+{sup 248}Cm Leading to the New Superheavy Nuclide {sup 271}Hs

    SciTech Connect

    Dvorak, J.; Dvorakova, Z.; Kruecken, R.; Nebel, F.; Perego, R.; Schuber, R.; Tuerler, A.; Wierczinski, B.; Yakushev, A.; Bruechle, W.; Jaeger, E.; Schaedel, M.; Schausten, B.; Schimpf, E.; Chelnokov, M.; Kuznetsov, A.; Yeremin, A.; Duellmann, Ch. E.; Eberhardt, K.; Nagame, Y.

    2008-04-04

    The analysis of a large body of heavy ion fusion reaction data with medium-heavy projectiles (6{<=}Z{<=}18) and actinide targets suggests a disappearance of the 3n exit channel with increasing atomic number of the projectile. Here, we report a measurement of the excitation function of the reaction {sup 248}Cm({sup 26}Mg,xn){sup 274-x}Hs and the observation of the new nuclide {sup 271}Hs produced in the 3n evaporation channel at a beam energy well below the Bass fusion barrier with a cross section comparable to the maxima of the 4n and 5n channels. This indicates the possible discovery of new neutron-rich transactinide nuclei using relatively light heavy ion beams of the most neutron-rich stable isotopes and actinide targets.

  14. Production and Separation of T = 1/2 Nuclides for {beta}--{nu} angular correlation measurements

    SciTech Connect

    Delahaye, P.; Bajeat, O.; Saint Laurent, M. G.; Thomas, J. C.; Traykov, E.; Lienard, E.; Ban, G.; Durand, D.; Flechard, X.; Naviliat-Cuncic, O.; Stora, T.; Collaboration: GANISOL Group

    2011-11-30

    The SPIRAL facility at GANIL, which uses the so-called ISOL method to produce radioactive ion beams, is being upgraded to extend its production capabilities to the metallic beams of neutron deficient isotopes. We discuss here the potentialities offered by this upgrade for the measurement of the {beta}--{nu} angular correlation in the {beta}--decay of mirror nuclides.

  15. Measurements of long-lived cosmogenic nuclides in returned comet nucleus samples

    NASA Technical Reports Server (NTRS)

    Nishiizumi, K.; Kohl, C. P.; Arnold, J. R.

    1989-01-01

    Measurements of long lived cosmic ray produced radionuclides have given much information on the histories and rates of surface evolution for meteorites, the Moon and the Earth. These nuclides can be equally useful in studying cometary histories and post nebular processing of cometary surfaces. The concentration of these nuclides depends on the orbit of the comet (cosmic ray intensity changes with distance from the sun), the depth of the sampling site in the comet surface, and the rate of continuous evolution of the surface (erosion rate of surface materials). If the orbital parameters and the sampling depth are known, production rates of cosmogenic nuclides can be fairly accurately calculated by theoretical models normalized to measurement on lunar surface materials and meteoritic samples. Due to the continuous evaporation of surface materials, it is expected that the long lived radioactivities will be undersaturated. Accurate measurements of the degree of undersaturation in nuclides of different half-lives allows for the determination of the rate of surface material loss over the last few million years.

  16. Bayesian estimation of a source term of radiation release with approximately known nuclide ratios

    NASA Astrophysics Data System (ADS)

    Tichý, Ondřej; Šmídl, Václav; Hofman, Radek

    2016-04-01

    We are concerned with estimation of a source term in case of an accidental release from a known location, e.g. a power plant. Usually, the source term of an accidental release of radiation comprises of a mixture of nuclide. The gamma dose rate measurements do not provide a direct information on the source term composition. However, physical properties of respective nuclide (deposition properties, decay half-life) can be used when uncertain information on nuclide ratios is available, e.g. from known reactor inventory. The proposed method is based on linear inverse model where the observation vector y arise as a linear combination y = Mx of a source-receptor-sensitivity (SRS) matrix M and the source term x. The task is to estimate the unknown source term x. The problem is ill-conditioned and further regularization is needed to obtain a reasonable solution. In this contribution, we assume that nuclide ratios of the release is known with some degree of uncertainty. This knowledge is used to form the prior covariance matrix of the source term x. Due to uncertainty in the ratios the diagonal elements of the covariance matrix are considered to be unknown. Positivity of the source term estimate is guaranteed by using multivariate truncated Gaussian distribution. Following Bayesian approach, we estimate all parameters of the model from the data so that y, M, and known ratios are the only inputs of the method. Since the inference of the model is intractable, we follow the Variational Bayes method yielding an iterative algorithm for estimation of all model parameters. Performance of the method is studied on simulated 6 hour power plant release where 3 nuclide are released and 2 nuclide ratios are approximately known. The comparison with method with unknown nuclide ratios will be given to prove the usefulness of the proposed approach. This research is supported by EEA/Norwegian Financial Mechanism under project MSMT-28477/2014 Source-Term Determination of Radionuclide Releases

  17. Analytical source term optimization for radioactive releases with approximate knowledge of nuclide ratios

    NASA Astrophysics Data System (ADS)

    Hofman, Radek; Seibert, Petra; Kovalets, Ivan; Andronopoulos, Spyros

    2015-04-01

    We are concerned with source term retrieval in the case of an accident in a nuclear power with off-site consequences. The goal is to optimize atmospheric dispersion model inputs using inverse modeling of gamma dose rate measurements (instantaneous or time-integrated). These are the most abundant type of measurements provided by various radiation monitoring networks across Europe and available continuously in near-real time. Usually, a source term of an accidental release comprises of a mixture of nuclides. Unfortunately, gamma dose rate measurements do not provide a direct information on the source term composition; however, physical properties of respective nuclides (deposition properties, decay half-life) can yield some insight. In the method presented, we assume that nuclide ratios are known at least approximately, e.g. from nuclide specific observations or reactor inventory and assumptions on the accident type. The source term can be in multiple phases, each being characterized by constant nuclide ratios. The method is an extension of a well-established source term inversion approach based on the optimization of an objective function (minimization of a cost function). This function has two quadratic terms: mismatch between model and measurements weighted by an observation error covariance matrix and the deviation of the solution from a first guess weighted by the first-guess error covariance matrix. For simplicity, both error covariance matrices are approximated as diagonal. Analytical minimization of the cost function leads to a liner system of equations. Possible negative parts of the solution are iteratively removed by the means of first guess error variance reduction. Nuclide ratios enter the problem in the form of additional linear equations, where the deviations from prescribed ratios are weighted by factors; the corresponding error variance allows us to control how strongly we want to impose the prescribed ratios. This introduces some freedom into the

  18. Intruder states of the odd-mass N=27 isotones

    NASA Astrophysics Data System (ADS)

    Yokoyama, Atsushi; Horie, Hisashi

    1985-03-01

    Energy levels and electromagnetic properties of the N=27 and 28 nuclei are studied systematically in terms of the shell model within the fn7/2+fn-17/2(p3/2,p1/2,f5/2)1 configurations. The effective interactons are made up of empirical matrix elements and phenomenological potentials superposed with two and three central interactions. Least-squares fitting calculations of selected energy levels are performed to fix some of the matrix elements and the strength parameters of the potentials. It is shown that some states with a collective nature appear in 51Cr and 53Fe which are connected to each other by the enhanced E2 transitions, whereas no such states appear in 47Ca and 49Ti. The anomalously large B(E2) values observed in the transitions between the intruder states can be reproduced very well. The hindrance of the E2 transitions between the intruder state and the normal fn7/2 state is obtained in the present model, being in qualitative agreement with the experiments. Both of the proton-neutron (p-n) interactions (1) among the f7/2 nucleons and (2) between the f7/2 and the other fp nucleons are very important in order to obtain proper understanding of the nuclei in this mass region.

  19. Scaling in situ cosmogenic nuclide production rates using analytical approximations to atmospheric cosmic-ray fluxes

    NASA Astrophysics Data System (ADS)

    Lifton, Nathaniel; Sato, Tatsuhiko; Dunai, Tibor J.

    2014-01-01

    Several models have been proposed for scaling in situ cosmogenic nuclide production rates from the relatively few sites where they have been measured to other sites of interest. Two main types of models are recognized: (1) those based on data from nuclear disintegrations in photographic emulsions combined with various neutron detectors, and (2) those based largely on neutron monitor data. However, stubborn discrepancies between these model types have led to frequent confusion when calculating surface exposure ages from production rates derived from the models. To help resolve these discrepancies and identify the sources of potential biases in each model, we have developed a new scaling model based on analytical approximations to modeled fluxes of the main atmospheric cosmic-ray particles responsible for in situ cosmogenic nuclide production. Both the analytical formulations and the Monte Carlo model fluxes on which they are based agree well with measured atmospheric fluxes of neutrons, protons, and muons, indicating they can serve as a robust estimate of the atmospheric cosmic-ray flux based on first principles. We are also using updated records for quantifying temporal and spatial variability in geomagnetic and solar modulation effects on the fluxes. A key advantage of this new model (herein termed LSD) over previous Monte Carlo models of cosmogenic nuclide production is that it allows for faster estimation of scaling factors based on time-varying geomagnetic and solar inputs. Comparing scaling predictions derived from the LSD model with those of previously published models suggest potential sources of bias in the latter can be largely attributed to two factors: different energy responses of the secondary neutron detectors used in developing the models, and different geomagnetic parameterizations. Given that the LSD model generates flux spectra for each cosmic-ray particle of interest, it is also relatively straightforward to generate nuclide-specific scaling

  20. Atomic nuclei decay modes by spontaneous emission of heavy ions

    NASA Astrophysics Data System (ADS)

    Poenaru, D. N.; Ivaşcu, M.; Sndulescu, A.; Greiner, Walter

    1985-08-01

    The great majority of the known nuclides with Z>40, including the so-called stable nuclides, are metastable with respect to several modes of spontaneous superasymmetric splitting. A model extended from the fission theory of alpha decay allows one to estimate the lifetimes and the branching ratios relative to the alpha decay for these natural radioactivities. From a huge amount of systematic calculations it is concluded that the process should proceed with maximum intensity in the trans-lead nuclei, where the minimum lifetime is obtained from parent-emitted heavy ion combinations leading to a magic (208Pb) or almost magic daughter nucleus. More than 140 nuclides with atomic number smaller than 25 are possible candidates to be emitted from heavy nuclei, with half-lives in the range of 1010-1030 s: 5He, 8-10Be, 11,12B, 12-16C, 13-17N, 15-22O, 18-23F, 20-26Ne, 23-28Na, 23-30Mg, 27-32Al, 28-36Si, 31-39P, 32-42S, 35-45Cl, 37-47Ar, 40-49 K, 42-51. . .Ca, 44-53 Sc, 46-53Ti, 48-54V, and 49-55 Cr. The shell structure and the pairing effects are clearly manifested in these new decay modes.

  1. Analysis of nuclide transport under natural convection and time dependent boundary condition using TOUGH2

    SciTech Connect

    Javeri, V.

    1995-03-01

    After implementation of TOUGH2 at GRS in summer 91, it was first used to analyse the gas transport in a repository for the nuclear waste with negligible heat generation and to verify the results obtained with ECLIPSE/JAV 92/. Since the original version of TOUGH2 does not directly simulate the decay of radionuclide and the time dependent boundary conditions, it is not a appropriate tool to study the nuclide transport in a porous medium/PRU 87, PRU 91/. Hence, in this paper some modifications are proposed to study the nuclide transport under combined influence of natural convection diffusion, dispersion and time dependent boundary condition. Here, a single phase fluid with two liquid components is considered as in equation of state model for water and brine/PRU 91A/.

  2. The exposure history of Jilin and production rates of cosmogenic nuclides

    NASA Technical Reports Server (NTRS)

    Heusser, G.

    1986-01-01

    Jilin, the largest known story meteorite, is a very suitable object for studying the systematics of cosmic ray produced nuclides in stony meteorites. Its well established two stage exposure history even permits to gain information about two different irradiation geometries (2pi and 4pi). All stable and long-lived cosmogenic nuclides measured in Jilin so far correlate well with each other. An example is shown where the Al-26 activities are plotted vs. the spallogenic Ne-21 concentration. These records of cosmic-ray interaction in Jilin can be used both to determine the history of the target and to study the nature of production rate profiles. This is unavoidably a bootstrap process, involving studying one with assumption about the other. Production rate equations are presented and discussed.

  3. The exposure history of Jilin and production rates of cosmogenic nuclides

    NASA Astrophysics Data System (ADS)

    Heusser, G.

    Jilin, the largest known story meteorite, is a very suitable object for studying the systematics of cosmic ray produced nuclides in stony meteorites. Its well established two stage exposure history even permits to gain information about two different irradiation geometries (2pi and 4pi). All stable and long-lived cosmogenic nuclides measured in Jilin so far correlate well with each other. An example is shown where the Al-26 activities are plotted vs. the spallogenic Ne-21 concentration. These records of cosmic-ray interaction in Jilin can be used both to determine the history of the target and to study the nature of production rate profiles. This is unavoidably a bootstrap process, involving studying one with assumption about the other. Production rate equations are presented and discussed.

  4. The even-odd systematics in R-process nuclide abundances

    NASA Technical Reports Server (NTRS)

    Marti, K.; Suess, H. E.

    1988-01-01

    The paper reports and discusses solar system N(R) abundances for nuclides A greater than 70, obtained as differences between measured solar system abundances and calculated S-process contributions. The abundance peak at A of about 163 in the rare earth element region reveals properties which are similar to those of the R-process peaks corresponding to magic neutron numbers N = 82 and N = 126. Systematic differences in the N(R) abundances of even-A and odd-A nuclides are restricted to specific mass regions. It is concluded that these differences are most probably related to the properties of nuclear species during beta(-) decay to the stability valley.

  5. Interplay of direct and compound-nucleus mechanisms in neutron capture by light nuclides

    SciTech Connect

    Raman, S.; Kahane, S.; Lynn, J.E.

    1988-01-01

    The authors discuss the direct-capture theory pertaining to primary electric-dipole (E1) transitions following slow-neutron capture. For approximately 20 light nuclides that we have studied, estimates of direct-capture cross sections using optical-model potentials with physically realistic parameters are in reasonable agreement with the data. Minor disagreements that exist are consistent with extrapolations to light nuclides of generally accepted formulations of compound-nucleus capture. In dealing with nuclei soft to vibrations, we have considered the possible effects of coupling of the collective motion with the optical potential in the framework of R-matrix theory. In such cases, we find that the inclusion of inelastic channels results in systematic changes in the calculated cross sections.

  6. On the calculation of activity concentrations and nuclide ratios from measurements of atmospheric radioactivity.

    PubMed

    Axelsson, A; Ringbom, A

    2014-09-01

    Motivated by the need for consistent use of concepts central to the reporting of results from measurements of atmospheric radioactivity, we discuss some properties of the methods commonly used. Different expressions for decay correction of the activity concentration for parent-daughter decay pairs are presented, and it is suggested that this correction should be performed assuming parent-daughter ingrowth in the sample during the entire measurement process. We note that, as has already been suggested by others, activities rather than activity concentrations should be used when nuclide ratios are calculated. In addition, expressions that can be used to transform activity concentrations to activity ratios are presented. Finally we note that statistical uncertainties for nuclide ratios can be properly calculated using the exact solution to the problem of confidence intervals for a ratio of two jointly normally distributed variables, the so-called Fieller׳s theorem. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. The spectrometric determination of the individual exposure rate for gamma nuclides from an environmental radiation detector

    SciTech Connect

    Young-Yong Ji; Kun Ho Chung; Wanno Lee; Doo-Won Park; Mun-Ja Kang

    2013-07-01

    For making the spectrometric determination of the exposure rate from the environment as well as the radioactive material more practical, an accurate calculation method of the individual exposure rate for the detected gamma nuclides from that spectrum should be suggested without the sophisticated calibration procedure. In this study, the calculation method for the individual exposure rate for detected gamma nuclides from a 3'x3' NaI(Tl) detector was suggested by introducing the concept of the dose rate spectroscopy and the peak-to-total ratio in the energy spectrum for the exposure rate, which means just a form of multiplied counts and the value of a G-factor in the spectrum. (authors)

  8. Studies on cosmogenic nuclides in meteorites with regard to an application as potential depth indicators

    NASA Technical Reports Server (NTRS)

    Sarafin, R.; Herpers, U.; Englert, P.; Wieler, R.; Signer, P.; Bonani, G.; Hofmann, H. J.; Morenzoni, E.; Nessi, M.; Suter, M.

    1986-01-01

    Measurements of stable and radioactive spallation products in meteorites allow to investigate their histories, especially with respect to the exposure to galactic cosmic ray particles and the pre-atmospheric size of the object. While the concentrations of spallation products lead to the determination of exposure and terrestrial ages, production rate ratios are characteristic for the location of the sample in the meteorite. So, one of the aims of this investigation on meteorites is to obtain depth indicators from suitable pairs of cosmogenic nuclides. Because of the different depth profiles for nuclide productions it is necessary to determine the concentrations of a larger number of spallation products in aliquots of a single small sample. Such same sample measurements of Be-10 and light noble gases were performed on 15 ordinary chondrites (7 H- and 8 L-chondrites. Be-10 was determined by accelerator mass spectrometry and the noble gases were measured by static mass spectrometry. The results are summarized and discussed.

  9. TOF-Bρ mass measurements of very exotic nuclides for astrophysical calculations at the NSCL

    NASA Astrophysics Data System (ADS)

    Matoš, M.; Estrade, A.; Amthor, M.; Aprahamian, A.; Bazin, D.; Becerril, A.; Elliot, T.; Galaviz, D.; Gade, A.; Gupta, S.; Lorusso, G.; Montes, F.; Pereira, J.; Portillo, M.; Rogers, A. M.; Schatz, H.; Shapira, D.; Smith, E.; Stolz, A.; Wallace, M.

    2008-01-01

    Atomic masses play a crucial role in many nuclear astrophysics calculations. The lack of experimental values for relevant exotic nuclides triggered a rapid development of new mass measurement devices around the world. The time-of-flight (TOF) mass measurements offer a complementary technique to the most precise one, Penning trap measurements (Blaum 2006 Phys. Rep. 425 1), the latter being limited by the rate and half-lives of the ions of interest. The NSCL facility provides a well-suited infrastructure for the TOF mass measurements of very exotic nuclei. At this facility, we have recently implemented a TOF-Bρ technique and performed mass measurements of neutron-rich nuclides in the Fe region, important for r-process calculations and for calculations of processes occurring in the crust of accreting neutron stars.

  10. Determination of Concentrations of Radioactive Nuclides in Soil Samples using Gamma Ray Spectroscopy

    NASA Astrophysics Data System (ADS)

    Adil, Arsalan; Weaver, Joshua

    2015-10-01

    A hyper-pure Germanium detector system was used to determine the contents and concentrations of various nuclides in soil samples collected from different parts of the United States. These include areas in close proximity to nuclear power plants, areas susceptible to nuclear fallout from weapons testing from the pre Comprehensive Nuclear Test Ban Treaty (CTBT) period, and areas vulnerable to fallout from Fukushima from the west coast. The concentrations of naturally occurring nuclides in the 238U, 232Th, and 40K decay chains as well as that of synthetic isotopes of 137Cs and 60Co were measured with the aid of Genie-2000 and Radware (gf3m). An efficiency curve was obtained by designing a simulation and compared with standard sources. The research, now in its next stage, aims to do the same in samples from Karachi (Pakistan) which is home to three nuclear power plant projects but has no available baseline radioactivity measurements. University of Richmond.

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

    NASA Astrophysics Data System (ADS)

    Santhosh, K. P.; Sukumaran, Indu

    2016-12-01

    The heavy particle decays that are probable from the isotopes of Z = 128 superheavy nuclei within the range A = 306-339 have been analyzed within the Coulomb and proximity potential model (CPPM). The study includes the evaluation of heavy particle decay half-lives of 24 clusters, including both odd and even clusters that are supposed to be emitted from the Z = 128 superheavy nuclei. The predicted values in comparison with the models Universal curve (UNIV), Universal decay law (UDL), and scaling law of Horoi et al. are observed to follow the same trend, and almost all the values lie well within the experimental limit ( T 1/2 <1030s). The interesting point of the study is the confirmation of the importance of neutron magicity in the superheavy region, noticed from the plots of log10( T 1/2) vs. neutron number of the daughter nuclei. The minimum observed corresponds to the daughter nucleus with N = 184, which strongly supports the possibility of N = 184 to be a shell closure number. Also, the abrupt increase in the half-lives at A = 330 of the parent nuclei is the signature of neutron magicity at N = 202 associated with the parent nuclei. In addition, in the emission of odd mass clusters, the odd-even staggering (OES) effect is found which is more prominent in the case of heavy odd mass clusters. Importantly, the different slopes and intercepts obtained from the Geiger-Nuttall plots of log10( T 1/2) vs. Q -1/2 confirming the presence of shell closure effect and the plot of universal curve of log10( T 1 /2) vs.-lnP revealed the reliability of the model CPPM.

  12. The Abundances of Nuclides Magnesium in the Atmospheres of Arcturus and Aldebaran

    NASA Astrophysics Data System (ADS)

    Gorbanjeva, T. I.; Kantzen, L. E.; Komarov, N. S.

    The abundances of nuclides magnesium in the atmospheres of Arcturus and Aldebaran thick and thin disks of Galaxy have been studied. The stars have various chromospheric activity. We used the new data on molecular constants of radiation for every electrically- vibrationally-rotating line of molecular system A2 Π-X2 Σ for MgH. The synthetic spectra were calculated. The values determined are generally close, but not equal, to the solar ratios.

  13. Measurement of radon/thoron and its daughter nuclides in room air.

    PubMed

    Suppian, R; Vegandraj, S; Kandaiya, S

    1992-07-01

    Pumping air through a soft tissue which acts as a membrane is a relatively easy and quick method to collect and measure radon/thoron and its daughter nuclides in air. Analysis of the activity of the radionuclides can be calculated using an alpha counter which has been calibrated. In this method the activity of radon/thoron cannot be separated from the activity of radionuclides already present in the aerosol or dust particles.

  14. Fabrication of a set of realistic torso phantoms for calibration of transuranic nuclide lung counting facilities

    SciTech Connect

    Griffith, R.V.; Anderson, A.L.; Sundbeck, C.W.; Alderson, S.W.

    1983-10-26

    A set of 16 tissue equivalent torso phantoms has been fabricated for use by major laboratories involved in counting transuranic nuclides in the lung. These phantoms, which have bone equivalent plastic rib cages, duplicate the performance of the DOE Realistic Phantom set. The new phantoms (and their successors) provide the user laboratories with a highly realistic calibration tool. Moreover, use of these phantoms will allow participating laboratories to intercompare calibration information, both on formal and informal bases. 3 refs., 2 figs.

  15. Total and spontaneous fission half-lives of the americium and curium nuclides

    SciTech Connect

    Holden, N.E.

    1984-01-01

    The total half-life and the half-life for spontaneous fission are evaluated for the various long-lived nuclides of interest. Recommended values are presented for /sup 241/Am, /sup 242m/Am, /sup 243/Am, /sup 242/Cm, /sup 243/Cm, /sup 244/Cm, /sup 245/Cm, /sup 246/Cm, /sup 247/Cm, /sup 248/Cm, and /sup 250/Cm. The uncertainties are provided at the 95% confidence limit for each of the recommended values.

  16. Measuring glacial erosion of bedrock landforms with cosmogenic nuclide depth profiles

    NASA Astrophysics Data System (ADS)

    Ploskey, Z. T.; Stone, J. O.

    2013-12-01

    Erosion by glaciers and ice sheet shapes alpine and continental topography, renews soil cover, and plays a crucial role in the long-term carbon cycle by exposing fresh silicate rock to weathering. Rates of glacial erosion are difficult to quantify directly, and sediment budgets provide only catchment-wide averages. We have developed a method for measuring long-term average subglacial erosion at the outcrop scale, based on inverse analysis of cosmogenic nuclide depth profiles. Cosmogenic nuclide production decreases with depth (markedly so by 2-3 m depth), but persists at low levels to depths of tens to hundreds of meters. Because subglacial erosion removes only the upper part of the nuclide profile, nuclides can accumulate in the deep production zone of the profile over many glacial cycles. Using the Neighorhood Algorithm, we invert depth profile measurements for posterior probability distributions of recent and long term average erosion rates. However, inversion using any method requires putting constraints on the fraction of time that the rock surface has been exposed, and for rapid erosion, low concentrations require difficult measurements. One can not deduce specific erosional history, but it is possible to approximate the erosion rate over the past million years or less. We measured Be-10 in trial profiles from quarry sections on glacially-shaped mountains in Maine. Initial results indicate glacial erosion rates at these sites of 70-80 m/Myr, assuming the surface is ice-covered 15% of the time. We plan to measure two drill cores from a third site, to contrast abrasion rates on the mountain summit with rates of erosion dominated by plucking from lee-side surfaces.

  17. Mass measurements of the shortest-lived nuclides à la MISTRAL

    NASA Astrophysics Data System (ADS)

    Lunney, D.; Vieira, N.; Audi, G.; Gaulard, C.; de Saint Simon, M.; Thibault, C.

    2006-04-01

    At Princeton in the 1960's, L.G. Smith invented an instrument of astonishing accuracy and rapid measurement time, derived from his so-called mass synchrometer. Using the same principle, a radiofrequency spectrometer was constructed in Orsay to measure masses of the shortest-lived nuclides at Cern's Isolde facility. Smith's spectrometer is now a museum piece, making the Orsay version (since baptized, MISTRAL) the sole example of such an instrument and the only one ever to be used on-line. Here we report on a measurement of the 65[thin space]ms half-life, NDZ nuclide performed with MISTRAL. The measured mass excess of [thin space]keV is compared with that obtained by ISOLTRAP, since independent measurements using different techniques assure a healthy gene pool for the recommended masses of the atomic mass evaluation. The nuclide is the heaviest for which a precise mass is of importance for the so-called Wigner energy. A discussion is presented concerning this Wigner energy, perhaps the last component of nuclear mass formulas resisting microscopic treatment.

  18. Synchrotron radiation based Mössbauer absorption spectroscopy of various nuclides

    NASA Astrophysics Data System (ADS)

    Masuda, Ryo; Kobayashi, Yasuhiro; Kitao, Shinji; Kurokuzu, Masayuki; Saito, Makina; Yoda, Yoshitaka; Mitsui, Takaya; Seto, Makoto

    2016-12-01

    Synchrotron-radiation (SR) based Mössbauer absorption spectroscopy of various nuclides is reviewed. The details of the measuring system and analysis method are described. Especially, the following two advantages of the current system are described: the detection of internal conversion electrons and the close distance between the energy standard scatterer and the detector. Both of these advantages yield the enhancement of the counting rate and reduction of the measuring time. Furthermore, SR-based Mössbauer absorption spectroscopy of 40K, 151Eu, and 174Yb is introduced to show the wide applicability of this method. In addition to these three nuclides, SR-based Mössbauer absorption spectroscopy of 61Ni, 73Ge, 119Sn, 125Te, 127I, 149Sm, and 189Os has been performed. We continue to develop the method to increase available nuclides and to increase its ease of use. The complementary relation between the time-domain method using SR, such as nuclear forward scattering and the energy-domain methods such as SR-based Mössbauer absorption spectroscopy is also noted.

  19. Cross Sections for the Production of Cosmogenic Nuclides with Protons up to 400 MeV for the Interpretation of Cosmic-Ray-produced Nuclides

    NASA Astrophysics Data System (ADS)

    Schiekel, Th.; Rosel, R.; Herpers, U.; Bodemann, R.; Leya, I.; Gloris, M.; Michel, R.; Dittrich, B.; Kubik, P.; Suter, M.

    1993-07-01

    Integral excitation functions of the cosmogenic nuclides are the basic requirement for the interpretation of interactions between cosmic ray particles and extraterrestrial and terrestrial matter. Together with the knowledge of primary and secondary particle fields inside an irradiated body, model calculations can be developed to interpret abundances of cosmogenic nuclides in dependencies of the irradiation history of the irradiated body and of the cosmic particle ray itself. The quality of those model calculations depends on the quality of the available cross-section database, which is neither comprehensive nor reliable for the most important nuclides like the long-lived radionuclides (i.e., 10Be, 26Al, 36Cl, 41Ca) and the stable rare gas isotopes. For a systematic investigation in this field of science we carried out several irradiation experiments with protons in the energy region between 45 MeV and 400 MeV at the Paul Scherrer Institut (Villigen, Switzerland) and the Laboratoire Nationale Saturne (Saclay, France) using the stacked foil technique. We included 21 different target elements with Z between 6 and 79 (C, N as Si3N4, O as SiO2, Mg, Al, Si, Ca as CaC2H2O4, Ti, V, Mn as Mn/Ni alloy, Fe, Co, Ni, Cu, Sr as SrF2, Y, Zr, Nb, Rh, Ba as Ba containing glass and Au) in our experiments. The proton fluxes were monitored via the reaction 27Al(p,3p3n)22Na using the evaluated data of [1]. Residual nuclides were measured by X-, gamma-, and after a chemical separation by accelerator mass spectrometry. In order to check the quality of our experimental procedures we included some target elements in our new experiments for which consistent excitation functions have already been determined [2,3,4]. Our new data show excellent agreement with the earlier measurements. We measured cross sections for more than 120 different reactions. Here we report on the results for target elements with Z up to 28. The exsisting database of experimental excitation functions for the production

  20. Production of neutron-rich nuclides in the heavy-element region via /sup 3/He-induced reactions

    SciTech Connect

    Chu, Y.Y.; Zhou, M.L.

    1982-01-01

    We have measured the production cross sections for /sup 233/Th and /sup 231/Th from the bombardment of /sup 238/U with /sup 3/He ions at 46-, 53-, and 60-MeV at the Brookhaven 60-in. isochronous cyclotron. We have also attempted to observe the decay of /sup 233/Ac produced via /sup 238/U(/sup 3/He,/sup 8/B) or equivalent reactions using 61 MeV /sup 3/He ions by first separating thorium from actinium and then performing chemical purifications on the second thorium sample into which the actinium has decayed. In the four experiments we performed, three gave results consistent with the ..beta.. half-life of /sup 233/Ac somewhat longer than 120 s and the production cross section from this target-projectile combination in the order of 1 to 2 ..mu..b.

  1. Cosmogenic nuclide shielding corrections determined via MCNPX radiation transport and spallation cross sections

    NASA Astrophysics Data System (ADS)

    Argento, D.; Reedy, R. C.; Stone, J. O.

    2011-12-01

    Cosmogenic Nuclides (CNs) are a critical new tool for geomorphology, allowing researchers to date Earth surface events and measure process rates [1]. Prior to CNs, many of these events and processes had no absolute method for measurement and relied entirely on relative methods. Reliable absolute measurement methods impact research constraining ice age extents and provide important climatic data via well constrained erosion rates, etc. [2]. Continuing to improve CN methods is critical for these sciences. Significant progress has been made in the last two decades in refining the method and reducing analytic uncertainties [1,3]. CRONUS-Earth, a collaboration of cosmogenic nuclide researchers, has been developing calibration data and scaling methods to provide a self-consistent platform for use in interpreting nuclide concentration values into geologic data. However, several aspects of the radiation cascade have been exceedingly difficult to measure empirically with either accuracy or spatial extent. One such aspect is the angular distribution of secondary cosmic rays that are energetic enough to produce cosmogenic nuclides via spallation. Researchers studying the angular distribution of such cosmic rays have usually described the distribution as (cos(Θ))^m. Currently, the standard corrections, assume an m of 2.3, which is based on very sparse data sets with very limited spatial and altitude variation [1,4,5]. Researchers using CNs must know the production rate at the sample location, and then make corrections for the portion of the sky that is blocked by nearby topography. If the shielding correction model currently used is too simplistic, this introduces error into the final results. In this study, a Monte Carlo method radiation transport code, MCNPX is used to model the Galactic Cosmic Ray (GCR) radiation impinging on the upper atmosphere and tracks the resulting secondary particles through a model of the Earth's atmosphere. Angle and energy distributions are

  2. Impact of vegetation change on the mobility of uranium- and thorium-series nuclides in soils

    NASA Astrophysics Data System (ADS)

    Gontier, A.; Rihs, S.; Turpault, M.-P.; Chabaux, F.

    2012-04-01

    The effect of land cover change on chemical mobility and soil response was investigated using short- and long-lived nuclides from the U- and Th series. Indeed, the matching of these nuclides half-live to the pedogenic processes rates make these nuclides especially suitable to investigate either time or mechanism of transfers within a soil-water-plant system. This study was carried out from the experimental Breuil-Chenue site (Morvan mountains, France). The native forest (150 year-old) was partially clear-felled and replaced in 1976 by mono-specific plantations distributed in different stands. Following this cover-change, some mineralogical changes in the acid brown soil were recognized (Mareschal, 2008). Three soil sections were sampled under the native forest and the replanted oak and Douglas spruce stands respectively. The (238U), (234U), (230Th), (226Ra), (232Th) and (228Ra) activities were analysed by thermal ionization mass spectrometry (TIMS), inductively coupled plasma mass spectrometry (MC-ICPMS) and gamma spectrometry. Significant differences in U, Th, and Ra activities were observed between the soils located under the native forest or the replanted-trees stands, mostly dominated by a large uranium mobilization from the replanted soils. Moreover, all the investigated U and Th-series activity ratios show a contrasted trend between the shallowest horizons (0-50cm) and the deepest one (below 50cm), demonstrating the chemical effect of the vegetation change on the shallow soil layers. Using a continuous open-system leaching model, the coupled radioactive disequilibria measured in the different soil layers permit to quantify the rate of the radionuclides mobilities. Reference: Mareschal, L., 2008. Effet des substitutions d'essences forestières sur l'évolution des sols et de leur minéralogie : bilan après 28 ans dans le site expérimental de Breuil (Morvan) Université Henri Poincaré, Nancy-I.

  3. Heavy Flavors

    NASA Astrophysics Data System (ADS)

    Cox, B.; Soni, A.

    This is a summary report of the working group on Heavy Flavors. Discussions at the workshop were centered on B physics and on the signals for heavy quarks and leptons at the SSC. The Working Group Members were: V. Barger, H.-U. Bengtsson, C. Buchanan, I. Bigi, M. Block, B. Cox, N. Glover, J. Hewett, W.Y. Keung, B. Margolis, T. Rizzo, M. Suzuki, A. Soni, D. Stork, and S. Willenbrock.

  4. Study on immobilization and migration of nuclide u in superficial soil of uranium tailings pond

    NASA Astrophysics Data System (ADS)

    Chang, Zhe; Zhou, Shukui

    2017-05-01

    The uranium tailings in southern China was used as the object of study to study the fixation and migration characteristics of nuclide U in shallow tailings. The results showed that the precipitation of tailings in the tailings soil was not linearly related to the depth during the acid rain leaching process. Tailings soil in the role of fixatives, when the lime as a fixative, the tailings of different soil uranium in 20 days after the re-precipitation. However, when lime and ammonium phosphate were used as fixing agents, the cumulative precipitation of U had a significant effect, and the migration of uranium was inhibited.

  5. The control mechanisms of erosion and weathering at basin scale from cosmogenic nuclides in river sediment

    NASA Astrophysics Data System (ADS)

    von Blanckenburg, Friedhelm

    2006-02-01

    The study of a sample of river sediment enables the determination of spatially averaged denudation rates that provide an exceptional perspective on erosion and weathering processes that have taken place within a landscape. These measurements are done with in-situ-produced cosmogenic nuclides (e.g., 10Be, 26Al), mostly in quartz from alluvial sediment. Cosmogenic nuclides are produced when secondary cosmic rays interact with the very uppermost layer of the Earth's surface. They are produced within a characteristic depth scale of about 1 m, which means that the measured concentrations record an integrated denudation history while material passed through this depth interval. Depending on the denudation rate the resulting integration time scales are 10 3 to 10 5 years, and one obtains a robust long-term estimate of natural denudation that is relatively insensitive to short-term changes. The last 10 years have seen significant research activity using these methods, and an array of fascinating tectono-geomorphologic and geochemical insights are emerging. Amongst these is the ability to identify the physical and chemical processes with which a landscape responds to tectonic activity or climate change. A compilation of world-wide denudation rates in non-glaciated areas, that however, does not yet include some of the world's most active mountain belts, has resulted in the following findings, some of which have been unexpected: (1) No obvious relationship between precipitation or mean annual temperature and total denudation is apparent. (2) Topographic relief alone does not result in high rates of denudation. (3) Denudation rates are high in areas of landscape rejuvenation; that is triggered and controlled by tectonic activity (faulting, escarpment formation and retreat, rifting, surface uplift). (4) Rates of weathering (using a combination of cosmogenic nuclides and zirconium-normalised cation loss balances) co-vary primarily with physical erosion rates and much less with

  6. The control mechanisms of erosion and weathering at basin scale from cosmogenic nuclides in river sediment

    NASA Astrophysics Data System (ADS)

    von Blanckenburg, Friedhelm

    2005-09-01

    The study of a sample of river sediment enables the determination of spatially averaged denudation rates that provide an exceptional perspective on erosion and weathering processes that have taken place within a landscape. These measurements are done with in-situ produced cosmogenic nuclides (e.g. 10Be, 26Al), mostly in quartz from alluvial sediment. Cosmogenic nuclides are produced when secondary cosmic rays interact with the very uppermost layer of the Earth's surface. They are produced within a characteristic depth scale of about 1 m, which means that the measured concentrations record an integrated denudation history while material passed through this depth interval. Depending on the denudation rate the resulting integration time scales are 10 3 to 10 5 years, and one obtains a robust long-term estimate of natural denudation that is relatively insensitive to short-term changes. The last 10 years have seen significant research activity using these methods, and an array of fascinating tectono-geomorphologic and geochemical insights are emerging. Amongst these is the ability to identify the physical and chemical processes with which a landscape responds to tectonic activity or climate change. A compilation of world-wide denudation rates in non-glaciated areas, that however, does not yet include some of the world's most active mountain belts, has resulted in the following findings, some of which have been unexpected: (1) No obvious relationship between precipitation or mean annual temperature and total denudation is apparent. (2) Topographic relief alone does not result in high rates of denudation. (3) Denudation rates are high in areas of landscape rejuvenation; that is triggered and controlled by tectonic activity (faulting, escarpment formation and retreat, rifting, surface uplift). (4) Rates of weathering (using a combination of cosmogenic nuclides and zirconium-normalised cation loss balances) co-vary primarily with physical erosion rates and much less with

  7. Total and spontaneous fission half-lives of the uranium and plutonium nuclides

    SciTech Connect

    Holden, N.E.

    1984-01-01

    The total half-life and the half-life for spontaneous fission are evaluated for the various long-lived nuclides of interest. Recommended values are presented for /sup 232/U, /sup 233/U, /sup 234/U, /sup 235/U, /sup 236/U, /sup 238/U, /sup 236/Pu, /sup 238/Pu, /sup 239/Pu, /sup 240/Pu, /sup 241/Pu, /sup 242/Pu, and /sup 244/Pu. The uncertainties are provided at the 95% confidence limit for each of the recommended values.

  8. TOF Mass Measurements of Very Exotic Nuclides: an Input for Astrophysical Calculations

    NASA Astrophysics Data System (ADS)

    Matoš, M.; Estrade, A.; Amthor, M.; Bazin, D.; Becerril, A.; Elliot, T.; Galaviz, D.; Gade, A.; Lorusso, G.; Montes, F.; Pereira, J.; Portillo, M.; Rogers, A. M.; Schatz, H.; Stolz, A.; Aprahamian, A.; Shapira, D.; Smith, E.; Gupta, S.; Wallace, M.

    2007-10-01

    Atomic masses play a crucial role in many nuclear astrophysics calculations. Very exotic nuclei can be accessed by time-of- flight techniques at radioactive beam facilities. The NSCL facility provides a well-suited infrastructure for TOF mass measurements of very exotic nuclei. At this facility, we have recently implemented a TOF-Bρ technique and performed mass measurements of neutron-rich nuclides in the Fe region, important for calculations of the r-process and processes occurring in the crust of accreting neutron stars. Description of the TOF technique, results and future plans related to nuclear astrophysics will be presented.

  9. Prompt neutron fission spectrum mean energies for the fissile nuclides and /sup 252/Cf

    SciTech Connect

    Holden, N.E.

    1985-01-01

    The international standard for a neutron spectrum is that produced from the spontaneous fission of /sup 252/Cf, while the thermal neutron induced fission neutron spectra for the four fissile nuclides, /sup 233/U, /sup 235/U, /sup 239/Pu, and /sup 241/Pu are of interest from the standpoint of nuclear reactors. The average neutron energies of these spectra are tabulated. The individual measurements are recorded with the neutron energy range measured, the method of detection as well as the average neutron energy for each author. Also tabulated are the measurements of the ratio of mean energies for pairs of fission neutron spectra. 75 refs., 9 tabs. (LEW)

  10. SHIPTRAP—a capture and storage facility for heavy radionuclides at GSI

    NASA Astrophysics Data System (ADS)

    Schönfelder, J.; Ackermann, D.; Backe, H.; Bollen, G.; Dilling, J.; Dretzke, A.; Engels, O.; Estermann, J.; Habs, D.; Hofmann, S.; Hessberger, F. P.; Kluge, H.-J.; Lauth, W.; Ludolphs, W.; Maier, M.; Marx, G.; Moore, R. B.; Quint, W.; Rodriguez, D.; Sewtz, M.; Sikler, G.; Toader, C.; Weber, Chr.; Shiptrap Collaboration

    2002-04-01

    SHIPTRAP will be an ion-trap facility for heavy radionuclides delivered from SHIP. Ion traps are a perfect instrument for precision measurements since the ions can be cooled to an extremely small phase space and can be stored for a very long time. In addition one can achieve very high purity by removing contaminant ions. SHIPTRAP will extend the possibilities of measurements in traps to transuranium nuclides and provide cooled and isobarically pure ion bunches.

  11. Correction of in situ cosmogenic nuclide production rates for geomagnetic field intensity variations during the past 800,000 years

    NASA Astrophysics Data System (ADS)

    Masarik, Jozef; Frank, Martin; Schäfer, Jörg M.; Wieler, Rainer

    2001-09-01

    We present integrated relative production rates for cosmogenic nuclides in rock surfaces, which take into account reported variations of the geomagnetic field intensity during the past 800,000 yr. The calculations are based on the model simulating cosmic ray particle interactions with the Earth's atmosphere given by Masarik and Beer ["Simulation of particle fluxes and cosmogenic nuclide production in the Earth's atmosphere," J. Geophys. Res. 104(D10), 12099-12111, 1999]. Corrections are nearly independent on altitude between sea level and at least 5000 m. The correction factors are essentially identical for all stable and radioactive cosmogenic nuclides with half-lives longer than a few hundred thousand years. At the equator, integrated production rates for exposure ages between ˜40,000 to 800,000 yr are 10 to 12% higher than the present-day values, whereas at latitudes >40°, geomagnetic field intensity variations have hardly influenced in situ cosmogenic nuclide production. Correction factors for in situ 14C production rates differ from those of longer-lived nuclides. They are always smaller than ˜2% because the magnetic field intensity remained rather constant during the past ˜10 kyr, when the major fraction of the 14C extant today was produced.

  12. Single-particle states in transcurium nuclei.

    SciTech Connect

    Ahmad, I.

    1999-09-30

    Identification of single-particle states in the heaviest known nuclei is important because their energies can be used to test the single-particle potential in these high-Z elements. These states can be identified by studying the decay schemes of very heavy odd-mass nuclides. For neutrons, the heaviest odd-mass nuclide available in milliCurie quantities is the 20-h {sup 255}Fm and for protons the heaviest nuclide available is the 20-d {sup 253}Es. These two isotopes were obtained from the Transplutonium Element Production Program at Oak Ridge and their spectra were measured with high-resolution germanium spectrometers. From the results of these measurements we have identified states in {sup 251}Cf and {sup 249}Bk up to 1 MeV excitation energy.

  13. The CAIRN method: automated, reproducible calculation of catchment-averaged denudation rates from cosmogenic nuclide concentrations

    NASA Astrophysics Data System (ADS)

    Marius Mudd, Simon; Harel, Marie-Alice; Hurst, Martin D.; Grieve, Stuart W. D.; Marrero, Shasta M.

    2016-08-01

    We report a new program for calculating catchment-averaged denudation rates from cosmogenic nuclide concentrations. The method (Catchment-Averaged denudatIon Rates from cosmogenic Nuclides: CAIRN) bundles previously reported production scaling and topographic shielding algorithms. In addition, it calculates production and shielding on a pixel-by-pixel basis. We explore the effect of sampling frequency across both azimuth (Δθ) and altitude (Δϕ) angles for topographic shielding and show that in high relief terrain a relatively high sampling frequency is required, with a good balance achieved between accuracy and computational expense at Δθ = 8° and Δϕ = 5°. CAIRN includes both internal and external uncertainty analysis, and is packaged in freely available software in order to facilitate easily reproducible denudation rate estimates. CAIRN calculates denudation rates but also automates catchment averaging of shielding and production, and thus can be used to provide reproducible input parameters for the CRONUS family of online calculators.

  14. Transformative progress in glacial chronology by systematic advances in cosmogenic nuclide dating

    NASA Astrophysics Data System (ADS)

    Schaefer, J. M.; Finkel, R. C.; Denton, G.; Kaplan, M. R.; Putnam, A.; Schwartz, R.; Barrell, D.

    2010-12-01

    Terrestrial cosmogenic nuclide dating has recently advanced the field of Quaternary Geology. However, systematic uncertainties have remained considerable enough to hamper the application of cosmogenic techniques to some geological fields. It has been the major goal of the CRONUS-Earth initiative to push the systematic understanding of terrestrial cosmogenic nuclide techniques to new limits and, in turn, to broaden and deepen the earth scientific application spectrum. Here we report progress in 10Be surface exposure dating towards better precision, higher internal consistency, higher temporal resolution, bigger sample sets and better overall accuracy and its transformative character for using the global glacial record as climate archive. Based on a large set of unpublished high-precision data from Holocene erratic boulders on moraines in New Zealand’s Southern Alps, Patagonia and the Alps, we discuss the potential and limits for dating very young surfaces and present novel possibilities to tie the precise chronologies of the glacial event record to continuous-high resolution records, such as treerings and ice cores. These novel glacier chronologies afford for new insights into the underlying driving mechanisms, pointing to strong inter-hemispheric discrepancies. Finally, we will discuss the impact of this progress on fields like natural hazards and surface process rates in high-erosion environments to illustrate the value of CRONUS-Earth for the wider earth scientific community.

  15. Cosmogenic nuclide age constraints on Middle Stone Age lithics from Niassa, Mozambique

    NASA Astrophysics Data System (ADS)

    Mercader, Julio; Gosse, John C.; Bennett, Tim; Hidy, Alan J.; Rood, Dylan H.

    2012-07-01

    The late phases of the Middle Stone Age (MSA) in the East African Rift System (EARS) are known for their evolutionary shifts and association with bottlenecks, transcontinental expansion, and climatic fluctuations. The chronology of MSA sites contemporaneous with these eco-demographic upheavals is uncertain because of the scarcity of datable sites and the poor understanding of their depositional and erosional histories. We apply terrestrial cosmogenic nuclide dating in a stratigraphic section with a complex exposure history to the study of the Luchamange Beds, a widespread sedimentological unit underlying MSA sites from the shores of Lake Niassa (Mozambican EARS). We use an innovative approach, which may be applicable elsewhere, to calculate their age using a Monte Carlo-based Bayesian model that links depth profiles of 26Al and 10Be, and uses other geomorphic and cosmogenic nuclide age constraints on episodic erosion and burial. The age of the basal Luchamange Beds is 42 + 77/-15 ka, and the MSA occupation on top is 29 + 3/-11 ka. These dates suggest temporal overlap between MSA and the earliest Later Stone Age and diversity in cultural manifestations at the end of the MSA.

  16. Runoff and sediment yield model for predicting nuclide transport in watersheds using BIOTRAN

    SciTech Connect

    Gallegos, A.F.; Wenzel, W.J.

    1990-09-01

    The environmental risk simulation model BIOTRAN was interfaced with a series of new subroutines (RUNOFF, GEOFLX, EROSON, and AQUIFER) to predict the movement of nuclides, elements, and pertinent chemical compounds in association with sediments through lateral and channel flow of runoff water. In addition, the movement of water into and out of segmented portions of runoff channels was modeled to simulate the dynamics of moisture flow through specified aquifers within the watershed. The BIOTRAN soil water flux subroutine, WATFLX, was modified to interface the relationships found in the SPUR model for runoff and sediment transport into channels with the particle sorting relationships to predict radionuclide enrichment and movement in watersheds. The new subroutines were applied specifically to Mortandad Canyon within Los Alamos National Laboratory by simultaneous simulation of eight surface vegetational subdivisions and associated channel and aquifer segments of this watershed. This report focuses on descriptions of the construction and rationale for the new subroutines and on discussing both input characteristics and output relationships to known runoff events from Mortandad Canyon. Limitations of the simplified input on model behavior are also discussed. Uranium-238 was selected as the nuclide for demonstration of the model because it could be assumed to be homogeneously distributed over the watershed surface. 22 refs., 18 figs., 9 tabs.

  17. BRIEF REPORT: Systematics of alpha-decay half-life: new evaluations for alpha-emitter nuclides

    NASA Astrophysics Data System (ADS)

    Medeiros, E. L.; Rodrigues, M. M. N.; Duarte, S. B.; Tavares, O. A. P.

    2006-08-01

    A semiempirical model based on the quantum-mechanical tunnelling mechanism of alpha emission from nuclei has been used to systematize the alpha-decay half-lives of a set of 336 nuclides, comprising all the alpha-emitter nuclides whose T1/2α-data for ground-state to ground-state transitions of mutual angular momentum ell = 0 are known. With a minimum of data rejection (only ~5% of cases), the procedure has been successful in reproducing quite satisfactorily (within a factor of ~2) most of the cases (~80%) investigated. A few significant discrepancies found between measured and calculated results are analysed and discussed. Also reported is the prediction from the model for possible new alpha-emitter nuclides, namely 180W, 184Os and 228Ra, for which cases the calculated partial alpha-decay half-lives fall within the range of half-lives measurable by the current techniques.

  18. HALF-LIVES OF LONG-LIVED A-DECAY, B-DECAY, BB-DECAY AND SPONTANEOUS FISSION NUCLIDES.

    SciTech Connect

    HOLDEN,N.E.

    2001-06-29

    In his review of radionuclides for dating purposes, Roth noted that there were a large number of nuclides, normally considered ''stable'' but which are radioactive with a very long half-life. Roth suggested that I review the data on the half-life values of these long-lived nuclides for a discussion session at the next meeting. These half-life values for long-lived nuclides include those due to various decay modes, {alpha}-decay, {beta}-decay, electron capture decay, {beta}{beta}-decay and spontaneous fission decay. This report is preliminary but will provide a quick overview of the extensive table of data on the recommendations from that review.

  19. Apparatus and method for quantitatively evaluating total fissile and total fertile nuclide content in samples. [Patent application

    DOEpatents

    Caldwell, J.T.; Kunz, W.E.; Cates, M.R.; Franks, L.A.

    1982-07-07

    Simultaneous photon and neutron interrogation of samples for the quantitative determination of total fissile nuclide and total fertile nuclide material present is made possible by the use of an electron accelerator. Prompt and delayed neutrons produced from resulting induced fission are counted using a single detection system and allow the resolution of the contributions from each interrogating flux leading in turn to the quantitative determination sought. Detection limits for /sup 239/Pu are estimated to be about 3 mg using prompt fission neutrons and about 6 mg using delayed neutrons.

  20. Calculated nuclide compositions and gamma-ray exposure rates for fallout from the HARRY, SMOKY, and ANNIE events

    SciTech Connect

    Hicks, H.G.

    1981-03-03

    The results of computer calculations of the nuclide composition and associated external gamma-ray exposure rates for fallout from the HARRY, SMOKY, and ANNIE events are documented. The fission product distribution is calculated for each event with the appropriate neutron spectrum and the fractions of fissions due to each fissionable material. Also calculated are the total number of microcuries per square meter and the gamma-ray exposure rates (mR/h, 1 meter above ground level) for the 152 fission products and 25 neutron-induced nuclides. The normalized data are presented in 9 Appendices. (DLS)

  1. Structure And Decay Of Neutron-Rich Nuclides In The 115 {<=} A {<=} 138 Mass Range And r-Process Nucleosynthesis

    SciTech Connect

    Walters, W.B.; Stoyer, M.A.; Shergur, J.; Hoteling, N.; Ressler, J.J.; Rikovska, J.; Kratz, K.-L.; Woehr, A.; Pfeiffer, B.; Arndt, O.; Mantica, P.F.; Tomlin, B.; Schatz, H.; Montes, F.; Brown, B.A.; Seweryniak, D.; Ravn, H.; Fedoseyev, V.; Koester, U.; Wu, C.Y.

    2005-04-05

    The structure and decay of neutron-rich r-process nuclides has been studied by a variety of means that take advantage of enhanced selectivity to permit identification of exotic nuclides. New level structures are presented for 134,135Sb along with data for Ag isomers and Cd yrast structures. Some of the properties measured play an important role in calculations of the yields of elements and isotopes produced in r-process nucleosynthesis that takes place at high temperature in the presence of large densities of neutrons.

  2. Comparing Time-Dependent Geomagnetic and Atmospheric Effects on Cosmogenic Nuclide Production Rate Scaling

    NASA Astrophysics Data System (ADS)

    Lifton, N. A.

    2014-12-01

    A recently published cosmogenic nuclide production rate scaling model based on analytical fits to Monte Carlo simulations of atmospheric cosmic ray flux spectra (both of which agree well with measured spectra) (Lifton et al., 2014, Earth Planet. Sci. Lett. 386, 149-160: termed the LSD model) provides two main advantages over previous scaling models: identification and quantification of potential sources of bias in the earlier models, and the ability to generate nuclide-specific scaling factors easily for a wide range of input parameters. The new model also provides a flexible framework for exploring the implications of advances in model inputs. In this work, the scaling implications of two recent time-dependent spherical harmonic geomagnetic models spanning the Holocene will be explored. Korte and Constable (2011, Phys. Earth Planet. Int. 188, 247-259) and Korte et al. (2011, Earth Planet. Sci. Lett. 312, 497-505) recently updated earlier spherical harmonic paleomagnetic models used by Lifton et al. (2014) with paleomagnetic measurements from sediment cores in addition to archeomagnetic and volcanic data. These updated models offer improved accuracy over the previous versions, in part to due to increased temporal and spatial data coverage. With the new models as input, trajectory-traced estimates of effective vertical cutoff rigidity (RC- the standard method for ordering cosmic ray data) yield significantly different time-integrated scaling predictions when compared to the earlier models. These results will be compared to scaling predictions using another recent time-dependent spherical harmonic model of the Holocene geomagnetic field by Pavón-Carrasco et al. (2014, Earth Planet. Sci. Lett. 388, 98-109), based solely on archeomagnetic and volcanic paleomagnetic data, but extending to 14 ka. In addition, the potential effects of time-dependent atmospheric models on LSD scaling predictions will be presented. Given the typical dominance of altitudinal over

  3. Regional Dispersal of Fukushima-derived Fission Nuclides by East Asia Monsoon

    NASA Astrophysics Data System (ADS)

    Huh, Chih-An; Lin, Chuan-Yao; Hsu, Shih-Chieh

    2013-04-01

    Since the Fukushima nuclear accident happened on 12 March 2011, there have been a plethora of publications about the dispersion of radioactive material from the damaged reactors. Most of these works dealt with global transport of Fukushima-derived radionuclides in the northern hemisphere and local transport in the vicinity of Fukushima and around Japan. In contrast, few works investigated into dispersal of radiation plumes from Japan to other areas on regional scales. This is because regional dispersal out of Japan in the springtime is most likely dominated by the northeastern monsoon, whereas there are few monitoring stations downwind in the southeastern Asia region. In this respect, we are only aware of the data in Vietnam published by Long et al (2012) in addition to our own data obtained in and around Taiwan (Huh et al., 2012; Hsu et al., 2012). By integrating the data published in the literature plus those that can be searched from relevant websites, we try to further elucidate the dispersal of Fukushima-derived radiation toward the southeastern Asia region. The WRF/Chem tracer model is employed to simulate the dispersal of radiation plumes from the damaged Fukushima Daiichi Nuclear Power Plant. From a vis-à-vis comparison between the model simulation and the time-series of Fukushima-derived fission nuclides monitored around the southeastern Asia, we can distinguish between global transport by the Westerlies in the free troposphere and regional transport by the northeast monsoon in the planetary boundary layer. In general, regional (mainly meridional) transport carried more weight than global (mainly zonal) transport in contributing Fukushima-derived radioactivity to the area covered in this review, particularly at the ground-level sites. References 1. Hsu, S.C., Huh, C.A., Chan, C.Y., Lin, S.H., Lin, F.J. and Liu, S.C. (2012). Hemispheric dispersion of radioactive plume laced with fission nuclides from the Fukushima nuclear event. Geophys. Res. Lett. 39, L00

  4. Plumbing neutron stars to new depths with the binding energy of the exotic nuclide 82Zn.

    PubMed

    Wolf, R N; Beck, D; Blaum, K; Böhm, Ch; Borgmann, Ch; Breitenfeldt, M; Chamel, N; Goriely, S; Herfurth, F; Kowalska, M; Kreim, S; Lunney, D; Manea, V; Minaya Ramirez, E; Naimi, S; Neidherr, D; Rosenbusch, M; Schweikhard, L; Stanja, J; Wienholtz, F; Zuber, K

    2013-01-25

    Modeling the composition of neutron-star crusts depends strongly on binding energies of neutron-rich nuclides near the N = 50 and N = 82 shell closures. Using a recent development of time-of-flight mass spectrometry for on-line purification of radioactive ion beams to access more exotic species, we have determined for the first time the mass of (82)Zn with the ISOLTRAP setup at the ISOLDE-CERN facility. With a robust neutron-star model based on nuclear energy-density-functional theory, we solve the general relativistic Tolman-Oppenheimer-Volkoff equations and calculate the neutron-star crust composition based on the new experimental mass. The composition profile is not only altered but now constrained by experimental data deeper into the crust than before.

  5. TUNL Nuclear Structure Data Evaluation on A = 2-20 Nuclides

    NASA Astrophysics Data System (ADS)

    Truong, Thinh; Kelley, John; Sheu, Grace

    2016-09-01

    Nuclear data represents measured or evaluated probabilities of various physical interactions involving the nuclei of atoms. The nuclear data group at Triangle Universities Nuclear Laboratory (TUNL) compiles, evaluates and disseminates nuclear structure data relevant to light nuclei in the mass region of A = 2 - 20. Our activities primarily involve surveying literature articles and producing recommended values for inclusion into various United States Nuclear Data Program databases, such as Experimental Unevaluated Nuclear Data List (XUNDL) and Evaluated Nuclear Structure Data File (ENSDF). We have projects related to analyzing beta-decay lifetimes, compiling structure data from recently published articles, and producing full nuclear structure data evaluations of nuclides based on all existing literature. The nuclear data disseminated is used for theoretical model development of nuclear physics and for applications involving radiation and nuclear power technologies. This work is supported by the U.S. National Science Foundation Grant No. NSF-PHY-1461204 and Duke/TUNL.

  6. Direct mass measurement of the four-neutron halo nuclide 8He.

    PubMed

    Ryjkov, V L; Brodeur, M; Brunner, T; Smith, M; Ringle, R; Lapierre, A; Ames, F; Bricault, P; Dombsky, M; Delheij, P; Lunney, D; Pearson, M R; Dilling, J

    2008-07-04

    A high-precision Penning trap mass measurement of the exotic 8He nuclide (T(1/2)=119 ms) has been carried out resulting in a reduction of the uncertainty of the halo binding energy by over an order of magnitude. The new mass, determined with a relative uncertainty of 9.2 x 10(-8) (deltam=690 eV) is 13 keV less bound than the previously accepted value. The mass measurement is of great relevance for the recent charge-radius measurement of 8He [P. Mueller, Phys. Rev. Lett. 99, 252501 (2007).10.1103/PhysRevLett.99.252501]. The 8He mass is the first result from the newly-commissioned Penning trap: TITAN (TRIUMF's Ion Trap for Atomic and Nuclear science) at the ISAC (Isotope Separator and Accelerator) radioactive beam facility at TRIUMF.

  7. Test of IMME in fp shell via direct mass measurements of nuclides

    NASA Astrophysics Data System (ADS)

    Zhang, Y. H.; Xu, H. S.; Litvinov, Yu A.; Tu, X. L.; Yan, X. L.; Typel, S.; Blaum, K.; Wang, M.; Zhou, X. H.; Sun, Y.; Brown, B. A.; Yuan, Y. J.; Xia, J. W.; Yang, J. C.; Audi, G.; Chen, X. C.; Jia, G. B.; Hu, Z. G.; Ma, X. W.; Mao, R. S.; Mei, B.; Shuai, P.; Sun, Z. Y.; Wang, S. T.; Xiao, G. Q.; Xu, X.; Yamaguchi, T.; Yamaguchi, Y.; Zang, Y. D.; Zhao, H. W.; Zhao, T. C.; Zhang, W.; Zhan, W. L.

    2013-03-01

    Isochronous mass spectrometry has been applied to neutron-deficient 58Ni projectile fragments at the HIRFL-CSR facility in Lanzhou, China. Masses of four shortlived Tz = -3/2 nuclides 41Ti, 45Cr, 49Fe, and 53Ni have been measured with a precision of 20 — 40 keV. The new mass data enabled for the first time to test the isobaric multiplet mass equation (IMME) in fp-shell nuclei. We observed that the IMME is inconsistent with the generally accepted quadratic form for the A = 53, T = 3/2 quartet. We performed full space shell model calculations and compared them with the new experimental results. The main results were published in Y.H. Zhang et al., Physical Review Letters 109 (2012). Here we give details on the experiment and data analysis as well as summarize the main findings.

  8. ANDROS: A code for Assessment of Nuclide Doses and Risks with Option Selection

    SciTech Connect

    Begovich, C.L.; Sjoreen, A.L.; Ohr, S.Y.; Chester, R.O.

    1986-11-01

    ANDROS (Assessment of Nuclide Doses and Risks with Option Selection) is a computer code written to compute doses and health effects from atmospheric releases of radionuclides. ANDROS has been designed as an integral part of the CRRIS (Computerized Radiological Risk Investigation System). ANDROS reads air concentrations and environmental concentrations of radionuclides to produce tables of specified doses and health effects to selected organs via selected pathways (e.g., ingestion or air immersion). The calculation may be done for an individual at a specific location or for the population of the whole assessment grid. The user may request tables of specific effects for every assessment grid location. Along with the radionuclide concentrations, the code requires radionuclide decay data, dose and risk factors, and location-specific data, all of which are available within the CRRIS. This document is a user manual for ANDROS and presents the methodology used in this code.

  9. Total and spontaneous fission half-lives for americium and curium nuclides

    SciTech Connect

    Holden, N.E.

    1985-01-01

    The long-lived nuclides of the americium curium elements are of interest for their use in certain safeguard applications and for nuclear reactor burnup studies in waste management. Recommended values are presented for /sup 241,242m,243/Am, and for /sup 242,243,244,245,246,247,248,250/Cm. These values result from a consistent evaluation of all these half-lives. These preliminary estimates were presented earlier. The uncertainties are provided at the 95% confidence limit for each of the recommended values. It will be noted that many of the recommended errors considerably exceed errors quoted by individual authors in their publication, by up to an order of magnitude, e.g., the total half-life of /sup 242,246,248/Cm and the spontaneous fission half-life of /sup 244/Cm. 65 refs., 18 tabs.

  10. Total and spontaneous fission half-lives for americium and curium nuclides

    NASA Astrophysics Data System (ADS)

    Holden, N. E.

    The long-lived nuclides of the americium curium elements are of interest for their use in certain safeguard applications and for nuclear reactor burnup studies in waste management. Recommended values are presented for /sup 241,242m,243/Am, and for /sup 242,243,244,245,246,247,248,250/Cm. These values result from a consistent evaluation of all these half-lives. These preliminary estimates were presented earlier. The uncertainties are provided at the 95% confidence limit for each of the recommended values. It will be noted that many of the recommended errors considerably exceed errors quoted by individual authors in their publication, by up to an order of magnitude, e.g., the total half-life of /sup 242,246,248/Cm and the spontaneous fission half-life of (244)Cm.

  11. Beta-spectroscopy of long lived nuclides with a PIPS detector-setup

    NASA Astrophysics Data System (ADS)

    Domula, Alexander R.; Thurn, Jan; Zuber, Kai

    2017-09-01

    Several applications in modern nuclear physics, research and engineering are limited by a lack of precise knowledge in spectral shape data for beta-decays. Specifically the interest aims to study spectral data for forbidden decays with respectively long half-lives, which is one of the central activities of our group. For the investigation of those rare beta-decays the group operates a setup of six PIPS detectors in a vacuum chamber built out of low-radioactivity materials. In the long term the setup will be used as low-background-detector for the investigation of rare beta-decays. In order to reduce the measuring-background a muon veto was installed. The characterization of the setup in the energy-range from 20..1000 keV using conversion-electrons is described. A set of useful calibration-nuclides was established to determine energy calibration and efficiencies.

  12. Cosmic-ray-produced stable nuclides: various production rates and their implications

    SciTech Connect

    Reedy, R.C.

    1981-06-15

    The rates for a number of reactions producing certain stable nuclides, such as /sup 3/He and /sup 4/He, and fission in the moon are calculated for galactic-cosmic-ray particles and for solar protons. Solar-proton-induced reactions with bromine usually are not an important source of cosmogenic Kr isotopes. The /sup 130/Ba(n,p) reaction cannot account for the undercalculation of /sup 130/Xe production rates. Calculated production rates of /sup 15/N, /sup 13/C, and /sup 2/H agree fairly well with rates inferred from measured excesses of these isotopes in samples with long exposure ages. Cosmic-ray-induced fission of U and Th can produce significant amounts of fission tracks and of /sup 86/Kr, /sup 134/Xe, and /sup 136/Xe, especially in samples with long exposures to cosmic-ray particles.

  13. Impact of Nuclear Data Uncertainties on Calculated Spent Fuel Nuclide Inventories and Advanced NDA Instrument Response

    DOE PAGES

    Hu, Jianwei; Gauld, Ian C.

    2014-12-01

    The U.S. Department of Energy’s Next Generation Safeguards Initiative Spent Fuel (NGSI-SF) project is nearing the final phase of developing several advanced nondestructive assay (NDA) instruments designed to measure spent nuclear fuel assemblies for the purpose of improving nuclear safeguards. Current efforts are focusing on calibrating several of these instruments with spent fuel assemblies at two international spent fuel facilities. Modelling and simulation is expected to play an important role in predicting nuclide compositions, neutron and gamma source terms, and instrument responses in order to inform the instrument calibration procedures. As part of NGSI-SF project, this work was carried outmore » to assess the impacts of uncertainties in the nuclear data used in the calculations of spent fuel content, radiation emissions and instrument responses. Nuclear data is an essential part of nuclear fuel burnup and decay codes and nuclear transport codes. Such codes are routinely used for analysis of spent fuel and NDA safeguards instruments. Hence, the uncertainties existing in the nuclear data used in these codes affect the accuracies of such analysis. In addition, nuclear data uncertainties represent the limiting (smallest) uncertainties that can be expected from nuclear code predictions, and therefore define the highest attainable accuracy of the NDA instrument. This work studies the impacts of nuclear data uncertainties on calculated spent fuel nuclide inventories and the associated NDA instrument response. Recently developed methods within the SCALE code system are applied in this study. The Californium Interrogation with Prompt Neutron instrument was selected to illustrate the impact of these uncertainties on NDA instrument response.« less

  14. Patterns of cosmogenic nuclide acquisition in the Sierra Nevada, Southern Spain

    NASA Astrophysics Data System (ADS)

    Reinhardt, L.; Bishop, P.; Dempster, T.; Hoey, T.; Fifield, K.; Barrows, T.

    2003-04-01

    Tectonically active mountain ranges are expected to respond rapidly to changes in base level. Sediment derived from such areas are expected to be rapidly delivered to sedimentary basins. A comprehensive terrestrial cosmogenic nuclide-based study aims to test these assumptions in an actively uplifting mountain block and to investigate particle transport paths prior to final deposition. The Sierra Nevada of western Spain is a tectonically active mountain range on the southern margin of the Eurasian plate. Thermochronological data indicate that the present day topography (maximum elevation 3480m) has developed within the past 10 Ma Our study focuses on the Rio Torrente catchment, a small (9km × 3km) east-west trending, 2000m relief catchment in the western Sierra Nevada. The Torrente has a denudationally stable headwater region of thick regolith cover and low slope angles, which passes abruptly downstream across a major knickpoint into the very steep topography of a drainage net that is currently experiencing a rejuvenation event. Frequent shallow bedrock landslides, promoted by a strong northward dipping bedrock schistosity, dominate rejuvenated areas. The distribution of Be-10 concentrations in sediment and bedrock corresponds very well with observed geomorphic processes within the Rio Torrente Catchment. Be-10 concentrations as low as 10 000 atoms/gram in bedrock and sediment, corresponding to apparent erosion rates in excess of 2mm per annum, characterise the steep landslide-dominated lower catchment. Areas of the catchment as yet unaffected by rejuvenation are readily identifiable through their relatively high Be-10 contents. GIS based data analysis, involving a simple tracking of particles across the landscape to estimate elevation histories during particle exhumation and transport, enables identification of the pattern of nuclide acquisition as sediment is generated and transported through the Rio Torrente Catchment.

  15. Impact of Nuclear Data Uncertainties on Calculated Spent Fuel Nuclide Inventories and Advanced NDA Instrument Response

    SciTech Connect

    Hu, Jianwei; Gauld, Ian C.

    2014-12-01

    The U.S. Department of Energy’s Next Generation Safeguards Initiative Spent Fuel (NGSI-SF) project is nearing the final phase of developing several advanced nondestructive assay (NDA) instruments designed to measure spent nuclear fuel assemblies for the purpose of improving nuclear safeguards. Current efforts are focusing on calibrating several of these instruments with spent fuel assemblies at two international spent fuel facilities. Modelling and simulation is expected to play an important role in predicting nuclide compositions, neutron and gamma source terms, and instrument responses in order to inform the instrument calibration procedures. As part of NGSI-SF project, this work was carried out to assess the impacts of uncertainties in the nuclear data used in the calculations of spent fuel content, radiation emissions and instrument responses. Nuclear data is an essential part of nuclear fuel burnup and decay codes and nuclear transport codes. Such codes are routinely used for analysis of spent fuel and NDA safeguards instruments. Hence, the uncertainties existing in the nuclear data used in these codes affect the accuracies of such analysis. In addition, nuclear data uncertainties represent the limiting (smallest) uncertainties that can be expected from nuclear code predictions, and therefore define the highest attainable accuracy of the NDA instrument. This work studies the impacts of nuclear data uncertainties on calculated spent fuel nuclide inventories and the associated NDA instrument response. Recently developed methods within the SCALE code system are applied in this study. The Californium Interrogation with Prompt Neutron instrument was selected to illustrate the impact of these uncertainties on NDA instrument response.

  16. The behavior of U- and Th-series nuclides in groundwater

    USGS Publications Warehouse

    Porcelli, D.; Swarzenski, P.W.

    2003-01-01

    Groundwater has long been an active area of research driven by its importance both as a societal resource and as a component in the global hydrological cycle. Key issues in groundwater research include inferring rates of transport of chemical constituents, determining the ages of groundwater, and tracing water masses using chemical fingerprints. While information on the trace elements pertinent to these topics can be obtained from aquifer tests using experimentally introduced tracers, and from laboratory experiments on aquifer materials, these studies are necessarily limited in time and space. Regional studies of aquifers can focus on greater scales and time periods, but must contend with greater complexities and variations. In this regard, the isotopic systematics of the naturally occurring radionuclides in the U- and Th- decay series have been invaluable in investigating aquifer behavior of U, Th, and Ra. These nuclides are present in all groundwaters and are each represented by several isotopes with very different half-lives, so that processes occurring over a range of time-scales can be studied (Table 1⇓). Within the host aquifer minerals, the radionuclides in each decay series are generally expected to be in secular equilibrium and so have equal activities (see Bourdon et al. 2003). In contrast, these nuclides exhibit strong relative fractionations within the surrounding groundwaters that reflect contrasting behavior during release into the water and during interaction with the surrounding host aquifer rocks. Radionuclide data can be used, within the framework of models of the processes involved, to obtain quantitative assessments of radionuclide release from aquifer rocks and groundwater migration rates. The isotopic variations that are generated also have the potential for providing fingerprints for groundwaters from specific aquifer environments, and have even been explored as a means for calculating groundwater ages.

  17. Early Acheulean technology in the Rietputs Formation, South Africa, dated with cosmogenic nuclides.

    PubMed

    Gibbon, Ryan J; Granger, Darryl E; Kuman, Kathleen; Partridge, Timothy C

    2009-02-01

    An absolute dating technique based on the build-up and decay of (26)Al and (10)Be in the mineral quartz provides crucial evidence regarding early Acheulean hominid distribution in South Africa. Cosmogenic nuclide burial dating of an ancient alluvial deposit of the Vaal River (Rietputs Formation) in the western interior of South Africa shows that coarse gravel and sand aggradation there occurred ca 1.57+/-0.22Ma, with individual ages of samples ranging from 1.89+/-0.19 to 1.34+/-0.22Ma. This was followed by aggradation of laminated and cross-bedded fine alluvium at ca 1.26+/-0.10Ma. The Rietputs Formation provides an ideal situation for the use of the cosmogenic nuclide burial dating method, as samples could be obtained from deep mining pits at depths ranging from 7 to 16 meters. Individual dates provide only a minimum age for the stone tool technology preserved within the deposits. Each assemblage represents a time averaged collection. Bifacial tools distributed throughout the coarse gravel and sand unit can be assigned to an early phase of the Acheulean. This is the first absolute radiometric dated evidence for early Acheulean artefacts in South Africa that have been found outside of the early hominid sites of the Gauteng Province. These absolute dates also indicate that handaxe-using hominids inhabited southern Africa as early as their counterparts in East Africa. The simultaneous appearance of the Acheulean in different parts of the continent implies relatively rapid technology development and the widespread use of large cutting tools in the African continent by ca 1.6Ma.

  18. On the production of cosmogenic nuclides by low-energy neutrons

    NASA Astrophysics Data System (ADS)

    Fanenbruck, O.; Lange, H.-J.; Michel, R.

    1994-07-01

    Monte Carlo codes describing the propagation and interaction of medium-energy particles in matter, in combination with experimental and theoretical cross sections of the underlying nuclear reactions, were successfully applied in model calculations of cosmogenic nuclide production rates. We extended these calculations to reactions of low-energy neutrons in order to allow a consistent interpretation of the entire regime of nuclear reactions involved in galactic cosmic ray (GCR) interactions. Low-energy neutron spectra were calculated for stony meteoroids and lunar surface materials by Monte Carlo techniques using the MORSE code, Emmett (1975), within the HERMES code system. Depth- and size-dependent production rates for the production of Cl-36, Ca-41, Co-60, Ni-59, Kr-80, and Kr-82 by neutron capture were derived by folding these spectra with group cross sections calculated from microscopic neutron-capture data of the evaluated neutron data file ENDF/B VI by the code NJOY. The calculations were validated by modeling the Co-60 production in an artificial stony meteoroid irradiated isotropically by 1.6 GeV protons. The new theoretical production rates were compared with earlier calculations of low-energy neutron capture by Eberhardt et al. and by Spergel et al. (n,gamma)-produced cosmogenic nuclides are sensitive indicators of meteoroid sizes. The extension of the model calculations to longlived and stable (n,gamma) products frees this method from the uncertainties caused by the short-term GCR variations that significantly affect Co-60 production rates. The new production rates are applied to the interpretation of the existing experimental data of (n,gamma) products in lunar drill cores and in meteorites.

  19. Can Morasko and Mundrabilla help Reconstructing Production Rates and Nuclear Reaction Cross-Sections for Light Cosmogenic Nuclides?

    NASA Astrophysics Data System (ADS)

    Merchel, S.; Smith, T.; Leya, I.; Pavetich, S.; Rugel, G.; Scharf, A.; Muszynski, A.

    2016-08-01

    Lighter nuclides of He, Ne, and Ar, and radionuclides Be-10, Al-26, Cl-36 and Ca-41 are measured in troilite, schreibersite and bulk metal of Mundrabilla and Morasko. Traces of S largely enhance Al-26 production. Cl-36-Ar-36 CRE ages are undisturbed.

  20. The tendency analytical equations of stable nuclides and the superluminal velocity motion laws of matter in geospace

    NASA Astrophysics Data System (ADS)

    Yan, Kun

    In this paper, by discussing the existent distribution trend of relation for the proton number and the neutron number to be included by the stable nuclides in geospace, the tendency analytical method and it's periodic distribution equation forms of the stable nuclides are expressed at first. Then the comparison result between the curve of the theoretical equation analysis and the points of the experimental distribution data of the stable nuclides in geospace are given. Further more, the stable nuclide limit and the chemical element limit for the chemical element periodic table are given, and the possible corresponding relation equation with the positron-particle annihilation is expressed, which includes the estimation of the order of the static mass to be situated nearby at the electron neutrino structural dimension. Subsequently, by forming two hypotheses about the energy state of vacuum matter, and basing on the equivalent Binet equation, the mass equations and the energy equations of the partial moving with light-velocity or superluminal-velocity motion fusing with the results of Einstein special relativity are expressed. As inference, the possible corresponding relations between the mass equations and energy equations with the dark matter and dark energy are discussed tentatively.

  1. Formation of super-heavy elements in astrophysical nucleosynthesis

    SciTech Connect

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

    2012-10-20

    The unexplored area of heavy neutron-rich nuclides is extremely important 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 'north-east' area of the nuclear map can be reached neither in fusion reactions nor in fragmentation processes. Low energy multi-nucleon transfer reactions are quite promising for the production and study of neutron-rich heavy nuclei including those located at the superheavy (SH) island of stability [1]. The neutron capture process is considered here as an alternative method for the production of SH nuclei. Requirements for the pulsed reactors of the next generation that could be used for the synthesis of long-living neutron rich SH nuclei are formulated. Formation of SH nuclei in supernova explosions is also discussed and the abundance of SH elements in nature is estimated.

  2. Simulation of Galactic Cosmic Ray Interactions with Regolith: Implications for Cosmogenic Nuclide and Planetary Surface Studies

    NASA Astrophysics Data System (ADS)

    Bobias, S. G.; Dempsey, J. F.; Englert, P. A. J.; Drake, D. M.; Reedy, R. C.

    1992-07-01

    In planetary, asteroidal, and cometary surfaces the development of cosmic ray produced secondary particle cascades depends very much on the chemical composition. Most important is the abundance and distribution of neutron moderators, such as hydrogen and carbon. Their presence influences the distribution and flux of neutrons in extraterrestrial surfaces. Consequently, the distribution and activity of neutron produced cosmogenic nuclides, such as the neutron capture products ^36Cl (3.01x10^5y), ^41Ca (1.03x10^5y), ^59Ni (7.6x10^4 y) and ^60Co (5.271y), and the medium energy products such as ^22Na (2.605 y, from Al), ^26Al (7.4x10^5 y, from Si), ^53Mn (3.7x10^6, from Fe), etc., will be dependent on the development of the secondary neutron fluxes. Three thick target bombardments of artificial planetary surface soil (martian) [1,2,3] that measured the secondary particle cascade as well as surface neutron flux and leakage spectra were performed at the Los Alamos Meson Physics Facility's Weapons Neutron Research Laboratory. They provide data to study qualitatively and quantitatively the relation between bombarding galactic cosmic ray particles, the development of neutrons inside a surface and of neutrons emitted from a planetary surface. Past thick target bombardments were limited to only determining the secondary particle cascades or the emitted gamma radiation [4,5,6]. The experiments show that the second target, which was two times larger than the target for the first experiment, was holding more neutrons inside the target. The third irradiation utilized a polyethylene sheet in front of the second target to simulate the presence of water or ice on a planetary surface. Threshold monitors were placed both along the axis of symmetry and radially displaced axes. The monitors included foils of Ti, Mn, Fe, Co, Ni, and Au. The induced radioactivity was measured at Los Alamos by conventional gamma-ray spectrometry approximately 48 hours at the end of irradiation. Both the

  3. Cenozoic landscape evolution in Terra Nova Bay region: new evidence from multiple cosmogenic nuclides

    NASA Astrophysics Data System (ADS)

    di Nicola, L.; Baroni, C.; Strasky, S.; Salvatore, M. C.; Schlüchter, C.; Akçar, N.; Kubik, P.; Wieler, R.

    2009-04-01

    Geomorphological surveys and cosmogenic nuclide analysis allow us to reconstruct the chronology of pre- LGM variations of the East Antarctic Ice Sheet (EAIS) and valley glaciers. In the Terra Nova Bay region, relict glacial features, such as glacially-scoured mountain tops and erratic fields are well preserved. The combination of noble gas (21Ne), and radionuclides (10Be and 26Al) are well suited to unravel the chronology of these glacial landforms. Exposure ages based on 10Be, 26Al and 21Ne data from weathered bedrock from the highest rounded summits of the coastal area (Mt. Abbott, Mt. Keinath and Mt. Crummer) demonstrate that they have been free of ice since at least 6 Ma (Northern Foothills and Boomerang Glacier area) and 4 Ma (Larsen Glacier area). This implies that glacially-scoured coastal piedmonts represent relict features that have not been overridden by erosive ice since at least the Pliocene. A similar scenario can be deduced from an inland area (60 km from the coast), located at the margin of the polar plateau (Mt. Pollock and the Archaumbault Ridge). Our data set strongly indicates a continuous exposure history for the relict alpine morphology, which is shown to be older than 6 to 7.5 Ma. In addition, denudation rates inferred by our data show that erosion of granite summits has been negligible. Erosion rates, ranging from 11 to 24 cm/Myr in the coastal area and below 9 cm/Myr further inland, indicate long lasting cold and hyperarid climate conditions. The combination of stable and radionuclide isotopes document complex exposure histories of the glacial drifts preserved in the coastal area. They allow us to identify different glacial phases which cannot be documented by geomorphic and glacial geologic evidence alone. Erratic boulders from 390 to 675 m asl, which are below the rounded summits of the coastal pedimonts and above the late-Pleistocene glacial drift preserved up to 350 m asl, yield variable exposure ages of 90 to 700 ka. This documents

  4. The rapidly advancing field of applications of nuclides produced in terrestrial solids in earth and planetary sciences

    NASA Astrophysics Data System (ADS)

    Lal, D.

    2005-12-01

    The field of cosmogenic in situ nuclides in terrestrial solids is about 2 decades old, beginning with the realization that the commonly occurring mineral quartz allowed convenient study of in situ produced nuclides, 10Be and 26Al (Lal and Arnold, 1985; Nishiizumi et al., 1985)), which in turn provide estimates of cosmic ray irradiation history of quartz. Since then the field has continually developed, providing time scales in several disciplines of paleoclimatology, geomorphology, tectonics, meteorology, and volcanology. Realizing the importance of determining accurate time scales in earth sciences, several scientists joined in to implement a project: Cosmic-Ray-Originated Nuclide Systematics on Earth Project (CRONUS), for improving rates of production of cosmogenic nuclides in targets exposed to cosmic radiation under different conditions. These efforts will undoubtedly immensely increase the potentials of the cosmogenic in situ method. In modeling of the cosmogenic nuclide data, one generally faces a dilemma in most cases, namely that one does not have sufficient amount of useful geological data about the samples under study. For instance, one of the principal obstacles constraining exposure histories is the information on its erosion and exfoliation history during exposure. A new approach is feasible to tackle the above mentioned shortcoming utilizing the unique feature of the cosmogenic interaction, namely that the cosmic ray flux at a given point within an object depends on the angular distribution of path lengths of cosmic ray particles arriving at the point from different directions. Interestingly, this distribution continuously changes as the surface of the object evolves with erosion and/or exfoliation. Herein lies the potential of determining both the exposure history and the evolutionary history of the solid object under investigation from multiple determinations of nuclide concentration at different points within a target. We present as examples

  5. Erosion of mountain plateaus along Sognefjord, Norway, constrained by cosmogenic nuclides

    NASA Astrophysics Data System (ADS)

    Andersen, Jane Lund; Egholm, David L.; Knudsen, Mads F.; Linge, Henriette; Jansen, John D.

    2016-04-01

    Norway is famous for its deeply incised, steep-sided fjords, carved out by glacial erosion. The high relief of the fjords stands in contrast to the extensive areas of relatively low relief found between the fjords. The origin and development of these low-relief areas remain debated. The classical interpretation relates them to a Mesozoic peneplanation surface, uplifted to the current high elevation in the early Cenozoic (e.g. Nesje, 1994). The validity of this interpretation has, however, been repeatedly questioned in recent times (e.g. Nielsen et al. 2009, Steer et al. 2012). Recent studies point instead to a significant impact of glacial and periglacial erosion processes on the long-term development of the low-relief surfaces (Egholm et al. 2015). Here, we present a large new dataset of in-situ produced cosmogenic 10Be and 26Al in bedrock and boulders from the high, flat summit surfaces along a transect from the coast to the inner parts of Sognefjorden in Norway. Our results indicate substantial glacial modification of the sampled low-relief surfaces within the last 50 ka. Close to the coast, at an elevation of around 700 meters, the cosmogenic nuclide signal was reset around the Younger Dryas due to extensive glacial erosion. Regarding the higher surfaces further inland, our results indicate a maximum cosmogenic nuclide inheritance of 20-30 ka prior to the last deglaciation. We do not find any signs of exceptional longevity of the low-relief landscape. In contrast, our results indicate that the low-relief areas were continuously eroded by glacial and periglacial processes in the Quaternary. Nesje & Whillans. Erosion of Sognefjord, Norway. Geomorphology 9(1), 33-45, 1994. Nielsen et al. The evolution of western Scandinavian topography: a review of Neogene uplift versus the ICE (isostasy-climate-erosion) hypothesis. Journal of Geodynamics 47(2), 72-95, 2009. Steer et al. Bimodal Plio-Quaternary glacial erosion of fjords and low-relief surfaces in Scandinavia

  6. Incision of the Yangtze River at the First Bend Determined by Three-Nuclide Burial Dating

    NASA Astrophysics Data System (ADS)

    McPhillips, D. F.; Hoke, G. D.; Rood, D. H.; Bierman, P. R.

    2015-12-01

    On the southeast margin of the Tibetan Plateau, the evolution of the Yangtze River and its major tributaries has become an important source of data for investigating geodynamics. In particular, the timing of river incision is frequently interpreted as a proxy for the timing of surface uplift in the absence of structural evidence. We investigate the timing of the incision of the gorge at the First Bend using cosmogenic nuclide burial dating of coarse, quartz sediments from caves. Sediments were deposited when the caves were near river level and subsequently abandoned as the river incised. To resolve burial ages >5 Ma, we measured the radionuclides 10Be and 26Al, and the stable nuclide 21Ne. Results from 4 caves show that 26Al and 10Be concentrations are an order of magnitude lower in abandoned cave samples than in a river-level cave sample where deposition is active (10Be: 1.3x104 and 3.4x105 at/g). In contrast, 26Al/10Be ratios in all caves are ≥6.2 and indistinguishable within error. 21Ne concentrations range from 2.1x106 to 7.8x106 at/g. The results are consistent with an old age for the abandoned cave deposits, such that most of the radionuclides initially present have decayed and the concentrations that we measure today are the result of millions of years of exposure to muons. We solve for burial ages, taking into account in situ muogenic production, and find that the majority of the gorge (1 km) was likely incised between ~12 and 9 Ma. The results also require that the rate of river incision declined after the gorge was cut below the lowest elevation cave at 9 Ma. Inverse modeling of published low-temperature thermochronology (Ouimet et al., 2010) supports our burial age results. River capture near the First Bend, which likely integrated the modern Yangtze, likely occurred prior to the mid-Miocene incision of the gorge. In view of the geographic position of the First Bend—just downslope from the southeast margin of the Plateau—it is difficult to explain

  7. Timing of European fluvial terrace formation and incision rates constrained by cosmogenic nuclide dating

    NASA Astrophysics Data System (ADS)

    Schaller, Mirjam; Ehlers, Todd A.; Stor, Tomas; Torrent, Jose; Lobato, Leonardo; Christl, Marcus; Vockenhuber, Christof

    2016-10-01

    Age constraints of late Cenozoic fluvial terraces are important for addressing surface process questions related to the incision rates of rivers, or tectonic and climate controls on denudation and sedimentation. Unfortunately, absolute age constraints of fluvial terraces are not always possible, and many previous studies have often dated terraces with relative age constraints that do not allow for robust interpretations of incision rates and timing of terrace formation. However, in situ-produced cosmogenic nuclides allow absolute age determination, and hence incision rates, of fluvial deposits back to 5 Ma. Here we present, cosmogenic depth profile dating and isochron burial dating of four different river systems in Europe spanning 12° of latitude. We do this to determine river incision rates and spatial variations in the timing of terrace formation. Isochron burial age constraints of four selected terraces from the Vltava river (Czech Republic) range between 1.00 ± 0.21 to 1.99 ± 0.45Ma. An isochron burial age derived for the Allier river (Central France) is 2.00 ± 0.17Ma. Five terrace levels from the Esla river (NW Spain) were dated between 0.08 + 0.04 / - 0.01Ma and 0.59 + 0.13 / - 0.20Ma with depth profile dating. The latter age agrees with an isochron burial age of 0.52 ± 0.20Ma. Two terrace levels from the Guadalquivir river (SW Spain) were dated by depth profile dating to 0.09 + 0.03 / - 0.02Ma and 0.09 + 0.04 / - 0.03Ma. The one terrace level from the Guadalquivir river dated by isochron burial dating resulted in an age of 1.79 ± 0.18Ma. Results indicate that the cosmogenic nuclide-based ages are generally older than ages derived from previous relative age constraints leading to a factor 2-3 lower incision rates than previous work. Furthermore, the timing of terrace formation over this latitudinal range is somewhat obscured by uncertainties associated with dating older terraces and not clearly synchronous with global climate variations.

  8. U-series nuclides migration from the vadose zone to a chalk aquifer

    NASA Astrophysics Data System (ADS)

    Hubert, A.; Bourdon, B.; Pili, E.

    2003-04-01

    We have studied the uranium-series disequilibria in chalk aquifer and the vadose zone above it in order to characterise the time scales of radionuclides migration from the water recharge zone of the aquifer to the river. Our field area is located in Champagne (France). The aquifer is characterized by a double porosity: matrix and fracture, providing both a fast and a slow pathways for water flow. We have collected both carbonate rocks and groundwater samples from boreholes and spring and river water from the same area. The boreholes have been drilled along a flow line. Rock/water interaction inside the aquifer induces dissolution and reprecipitation of carbonates, together with a mobilisation of uranium, and additionally the decay of radionuclides results in a-recoil effect particularly for the 234U--238U pair. We have measured uranium and thorium isotopes for carbonates samples from the aquifer by TIMS and multi-collection ICP-MS. The fractionation of uranium and thorium nuclides is distinctive in the various parts of the aquifer. Rock samples from the saturated zone show a depletion in 234U with a (234U/238U) ratio ranging from 0.945 to 0.993 (± 0.005). This indicates that uranium 234U has been released by rock/water interaction over the last million year. Nevertheless, rock samples from the vadose zone display an activity ratio 234U/238U above 1 and range from 1.002 to 1.052 (± 0.005), suggesting uranium reprecipitation possibly by a redox front. (230Th/238U) ratio range from 1.25 to 1.59 (± 0.03) in both saturated and vadose zone, whilst (230Th/232Th) ratio vary from 1.89 to 5.68 (± 0.05) with the highest values for the vadose zone. The 234U--230Th system shows a significant mobility of uranium less than 300 000 years ago within the aquifer. We are curently analysing water samples which will provide us further insights on the migration timescale of uranium-series nuclides in groundwater and will document the processes of groundwater/carbonate interaction.

  9. Production of heavy isotopes in transfer reactions by collisions of {sup 238}U+{sup 238}U

    SciTech Connect

    Feng Zhaoqing; Jin Genming; Li Junqing

    2009-12-15

    The dynamics of transfer reactions in collisions of two very heavy nuclei {sup 238}U+{sup 238}U is studied within the dinuclear system (DNS) model. Collisions of two actinide nuclei form a superheavy composite system during a very short time, in which a large number of charge and mass transfers may take place. Such reactions have been investigated experimentally as an alternative way for the production of heavy and superheavy nuclei. The role of collision orientation in the production cross sections of heavy nuclides is analyzed systematically. Calculations show that the cross sections decrease drastically as the charged numbers of the heavy fragments increase. The transfer mechanism is favorable to synthesizing heavy neutron-rich isotopes, such as nuclei around the subclosure at N=162 from No (Z=102) to Db (Z=105)

  10. Dating the incision of the Yangtze River gorge at the First Bend using three-nuclide burial ages

    NASA Astrophysics Data System (ADS)

    McPhillips, Devin; Hoke, Gregory D.; Liu-Zeng, Jing; Bierman, Paul R.; Rood, Dylan H.; Niedermann, Samuel

    2016-01-01

    Incision of the Yangtze River gorge is widely interpreted as evidence for lower crustal flow beneath the southeast margin of the Tibetan Plateau. Previous work focused on the onset of incision, but the duration of incision remains unknown. Here we present cosmogenic nuclide burial ages of sediments collected from caves on the walls of the gorge that show the gorge was incised ~1 km sometime between 18 and 9 Ma. Thereafter, incision slowed substantially. We resolve middle Miocene burial ages by using three nuclides and accounting for in situ muogenic production. This approach explains the absolute concentrations of 10Be, 26Al, and 21Ne, as well as 26Al/10Be and 21Ne/10Be ratios. A declining incision rate challenges existing geodynamic interpretations by suggesting that either (1) surface uplift has ceased immediately south of the plateau margin or (2) gorge incision is not a useful proxy for the timing of surface uplift.

  11. Cosmogenic nuclides in core samples of the Chico L6 chondrite - Evidence for irradiation under high shielding

    NASA Technical Reports Server (NTRS)

    Garrison, D. H.; Bogard, D. D.; Albrecht, A. A.; Vogt, S.; Herzog, G. F.; Klein, J.; Fink, D.; Dezfouly-Arjomandy, B.; Middleton, R.

    1992-01-01

    Results are presented from an analysis of core samples obtained from different depths of the Chico (New Mexico) L6 chondrite for various cosmogenic nuclides (Be-10, Al-26, and stable isotopes of He, Ne, and Ar). The relationships between the measured abundances of cosmogenic nuclides and cosmogenic Ne-22/Ne-21 ratio were compared with predictions of recent semiempirical models of Graf et al. (1990) and Reedy (1991), and it was found that both models closely reproduce the observed trends and absolute values of the data obtained. Noble gas data indicate that Chico experienced shielding similar to that of Jilin and greater than those of the Knyahinya or the Keyes chondrites. The exposure history for Chico is discussed.

  12. First Use of High Charge States for Mass Measurements of Short-Lived Nuclides in a Penning Trap

    SciTech Connect

    Ettenauer, S.; Gallant, A. T.; Dilling, J.; Simon, M. C.; Chaudhuri, A.; Mane, E.; Delheij, P.; Pearson, M. R.; Brunner, T.; Chowdhury, U.; Simon, V. V.; Brodeur, M.; Andreoiu, C.; Audi, G.; Lopez-Urrutia, J. R. Crespo; Ullrich, J.; Gwinner, G.; Lapierre, A.; Lunney, D.; Ringle, R.

    2011-12-30

    Penning trap mass measurements of short-lived nuclides have been performed for the first time with highly charged ions, using the TITAN facility at TRIUMF. Compared to singly charged ions, this provides an improvement in experimental precision that scales with the charge state q. Neutron-deficient Rb isotopes have been charge bred in an electron beam ion trap to q=8-12+ prior to injection into the Penning trap. In combination with the Ramsey excitation scheme, this unique setup creating low energy, highly charged ions at a radioactive beam facility opens the door to unrivaled precision with gains of 1-2 orders of magnitude. The method is particularly suited for short-lived nuclides such as the superallowed {beta} emitter {sup 74}Rb (T{sub 1/2}=65 ms). The determination of its atomic mass and an improved Q{sub EC} value are presented.

  13. Cosmogenic nuclides in core samples of the Chico L6 chondrite - Evidence for irradiation under high shielding

    NASA Technical Reports Server (NTRS)

    Garrison, D. H.; Bogard, D. D.; Albrecht, A. A.; Vogt, S.; Herzog, G. F.; Klein, J.; Fink, D.; Dezfouly-Arjomandy, B.; Middleton, R.

    1992-01-01

    Results are presented from an analysis of core samples obtained from different depths of the Chico (New Mexico) L6 chondrite for various cosmogenic nuclides (Be-10, Al-26, and stable isotopes of He, Ne, and Ar). The relationships between the measured abundances of cosmogenic nuclides and cosmogenic Ne-22/Ne-21 ratio were compared with predictions of recent semiempirical models of Graf et al. (1990) and Reedy (1991), and it was found that both models closely reproduce the observed trends and absolute values of the data obtained. Noble gas data indicate that Chico experienced shielding similar to that of Jilin and greater than those of the Knyahinya or the Keyes chondrites. The exposure history for Chico is discussed.

  14. A multi-layered active target for the study of neutron-unbound nuclides at NSCL

    NASA Astrophysics Data System (ADS)

    Freeman, Jessica; Gueye, Paul; Redpath, Thomas; MoNA Collaboration

    2017-01-01

    The characteristics of neutron-unbound nuclides were investigated using a multi-layered Si/Be active target designed for use with the MoNA/LISA setup at the National Superconducting Cyclotron (NSCL). The setup consists of the MoNA/LISA arrays (for neutron detection) and a superconducting sweeper magnet (for charged separation) to identify products following the decay of neutron unbound states. The segmented target consisted of three 700 mg/cm2 beryllium targets and four 0.14 mm thick 62x62 mm2 silicon detectors. As a commissioning experiment for the target the decay of two-neutron unbound 26O populated in a one-proton removal reaction from a radioactive 27F beam was performed. The 27F secondary radioactive beam from the NSCL's Coupled Cyclotron Facility was produced from the fragmentation of a 140 MeV/u 48Ca beam incident on a thick beryllium target and then cleanly selected by the A1900 fragment separator. The energy loss and position spectra of the incoming beam and reaction products were used to calibrate the Silicon detectors to within 1.5% in both energy and position. A dedicated Geant4 model of the target was developed to simulate the energy loss within the target. A description of the experimental setup, simulation work, and energy and position calibration will be presented. DoE/NNSA - DE-NA0000979.

  15. Activity concentration of natural radioactive nuclides in nonmetallic industrial raw materials in Japan.

    PubMed

    Iwaoka, Kazuki; Tabe, Hiroyuki; Yonehara, Hidenori

    2014-11-01

    Natural materials such as rock, ore, and clay, containing natural radioactive nuclides are widely used as industrial raw materials in Japan. If these are high concentrations, the workers who handle the material can be unknowingly exposed to radiation at a high level. In this study, about 80 nonmetallic natural materials frequently used as industrial raw materials in Japan were comprehensively collected from several industrial companies, and the activity concentrations of (238)U series, (232)Th series and (40)K in the materials was determined by ICP-MS (inductively-coupled plasma mass spectrometer) and gamma ray spectrum analyses. Effective doses to workers handling them were estimated by using methods for dose estimation given in the RP 122. We found the activity concentrations to be lower than the critical values defined by regulatory requirements as described in the IAEA Safety Guide. The maximum estimated effective dose to workers handling these materials was 0.16 mSv y(-1), which was lower than the reference level (1-20 mSv y(-1)) for existing situation given in the ICRP Publ.103.

  16. Studies of Itokawa's Surface Exposure by Measurements of Cosmic-ray Produced Nuclides

    NASA Technical Reports Server (NTRS)

    Caffee, M. W.; Nishiizumi, K.; Tsuchiyama, A.; Uesugi, M.; Zolensky, M. E.

    2014-01-01

    We plan to investigate the evolutionary history of surface materials from 25143 Itokawa, the Hayabusa samples. Our studies are based on the measurement of nuclides produced in asteroidal surface materials by cosmic rays. Cosmogenic radionuclides are used to determine the duration and nature of the exposure of materials to energetic particles. Our goals are to understand both the fundamental processes on the asteroidal surface and the evolutionary history of its surface materials. They are also key to understanding the history of Itokawa's surface and asteroid-meteoroid evolutionary dynamics. To achieve our key goals, in particular reconstructing the evolutionary histories of the asteroidal surface, we proposed: (1) characterizing Itokawa particles using SXCT, SXRD, and FE-SEM without modification of the sample; (2) embedding each particle in acrylic resin, then slicing a small corner with an ultra-microtome and examining it using super-STEM and SIMS for characterizing surface morphology, space weathering, and oxygen three-isotope analysis; and finally (3) measuring small amounts of cosmogenic radionuclides (104-105 atoms) in Hayabusa samples by AMS. However, we have to modify our plan due to unexpected situation.

  17. Cosmogenic nuclide dating of Sahelanthropus tchadensis and Australopithecus bahrelghazali: Mio-Pliocene hominids from Chad.

    PubMed

    Lebatard, Anne-Elisabeth; Bourlès, Didier L; Duringer, Philippe; Jolivet, Marc; Braucher, Régis; Carcaillet, Julien; Schuster, Mathieu; Arnaud, Nicolas; Monié, Patrick; Lihoreau, Fabrice; Likius, Andossa; Mackaye, Hassan Taisso; Vignaud, Patrick; Brunet, Michel

    2008-03-04

    Ages were determined at two hominid localities from the Chad Basin in the Djurab Desert (Northern Chad). In the Koro Toro fossiliferous area, KT 12 locality (16 degrees 00'N, 18 degrees 53'E) was the site of discovery of Australopithecus bahrelghazali (Abel) and in the Toros-Menalla fossiliferous area, TM 266 locality (16 degrees 15'N, 17 degrees 29'E) was the site of discovery of Sahelanthropus tchadensis (Toumaï). At both localities, the evolutive degree of the associated fossil mammal assemblages allowed a biochronological estimation of the hominid remains: early Pliocene (3-3.5 Ma) at KT 12 and late Miocene ( approximately 7 Ma) at TM 266. Atmospheric (10)Be, a cosmogenic nuclide, was used to quasicontinuously date these sedimentary units. The authigenic (10)Be/(9)Be dating of a pelite relic within the sedimentary level containing Abel yields an age of 3.58 +/- 0.27 Ma that points to the contemporaneity of Australopithecus bahrelghazali (Abel) with Australopithecus afarensis (Lucy). The 28 (10)Be/(9)Be ages obtained within the anthracotheriid unit containing Toumaï bracket, by absolute dating, the age of Sahelanthropus tchadensis to lie between 6.8 and 7.2 Ma. This chronological constraint is an important cornerstone both for establishing the earliest stages of hominid evolution and for new calibrations of the molecular clock.

  18. Applications of in situ cosmogenic nuclides in the geologic site characterization of Yucca Mountain, Nevada

    SciTech Connect

    Gosse, J.C.; Harrington, C.D.; Whitney, J.W.

    1996-08-01

    The gradual buildup of rare isotopes from interactions between cosmic rays and atoms in an exposed rock provides a new method of directly determining the exposure age of rock surfaces. The cosmogenic nuclide method can also provide constraints on erosion rates and the length of time surface exposure was interrupted by burial. Numerous successful applications of the technique have been imperative to the complete surface geologic characterization of Yucca Mountain, Nevada, a potential high level nuclear waste repository. The {sup 10}Be exposure age of Black Cone lava, within a ten mile radius of the proposed repository site, is 840 {+-} 210 kyr (in agreement with previous K/Ar dates of 1.0 {+-} 0.1 Ma). Rates of erosion of the tuff bedrock (< 0.4 cm/kyr from 7 {sup 10}Be measurements) and of hillslope colluvium ({approximately} 0.5 cm/kyr from {sup 10}Be dates on boulder deposits) preclude denudation of the mountain as a concern. Neotectonic concerns (rate of slip and timing of last significant movement along faults) are also being addressed with in situ {sup 14}C and {sup 10}Be measurements on scarp surfaces and on fault-dissected landforms where no surficial expression of the fault is preserved.

  19. CosmoCalc: An Excel add-in for cosmogenic nuclide calculations

    NASA Astrophysics Data System (ADS)

    Vermeesch, Pieter

    2007-08-01

    As dating methods using Terrestrial Cosmogenic Nuclides (TCN) become more popular, the need arises for a general-purpose and easy-to-use data reduction software. The CosmoCalc Excel add-in calculates TCN production rate scaling factors (using Lal, Stone, Dunai, and Desilets methods); topographic, snow, and self-shielding factors; and exposure ages, erosion rates, and burial ages and visualizes the results on banana-style plots. It uses an internally consistent TCN production equation that is based on the quadruple exponential approach of Granger and Smith (2000). CosmoCalc was designed to be as user-friendly as possible. Although the user interface is extremely simple, the program is also very flexible, and nearly all default parameter values can be changed. To facilitate the comparison of different scaling factors, a set of converter tools is provided, allowing the user to easily convert cut-off rigidities to magnetic inclinations, elevations to atmospheric depths, and so forth. Because it is important to use a consistent set of scaling factors for the sample measurements and the production rate calibration sites, CosmoCalc defines the production rates implicitly, as a function of the original TCN concentrations of the calibration site. The program is best suited for 10Be, 26Al, 3He, and 21Ne calculations, although basic functionality for 36Cl and 14C is also provided. CosmoCalc can be downloaded along with a set of test data from http://cosmocalc.googlepages.com.

  20. Development of the sampling and nuclide analysis methods for spent HEPA filter wastes

    SciTech Connect

    Young-Yong Ji; Dae Seok Hong; Il-Sik Kang; Bum-Kyoung Seo; Jong-Sik Shon

    2007-07-01

    Spent filter wastes of about 2,160 units have been stored in the waste storage facility of the Korea Atomic Energy Research Institute since its operation. These spent filters have generally consisted of a HEPA filter after its filtering of all the contaminants in the gas stream generated during the operation of the HANARO research reactor and the nuclear fuel cycle facilities. At the moment, to secure enough storage space, it is necessary to make a volume reduction of the stored radioactive wastes through a compression treatment or a regulatory clearance. There have been many studies on a treatment and a clearance of the low level radioactive wastes generated from nuclear facilities. These methods are used in view of a reduction of a management cost and disposal cost and the security of free space for a waste storage facility approaching saturation. In order to dispose of the spent filters, it is first necessary to conduct a radionuclide assessment of them. To do that, a sampling procedure should be prepared to obtain a representative sample from a spent filter. As for conducting a nuclide analysis for this representative sample, a corresponding spent filter can be determined as either a regulatory clearance waste or a radioactive waste. (authors)

  1. Gamow-Teller strength in the beta decay of mirror nuclides

    NASA Astrophysics Data System (ADS)

    Honkanen, J.; ńystö, J.; Koponen, V.; Taskinen, P.; Eskola, K.; Messelt, S.; Ogawa, K.

    1987-12-01

    Distribution of the Gamow-Teller strength has been studied both experimentally and theoretically in the f7/2 shell mirror nuclides over a wide energy range. Experimental studies were performed using light ion induced reactions and the He-jet transport method or the ion-guide on-line isotope separation, IGISOL. Several transitions were observed to excited states in the decays of 43Ti and 51Fe and some in the decays of 47Cr, 49Mn, 43Co and 55Ni. Theoretical calculations were made by a shell model code using fn7/2+(P3/2, f5/2, P1/2)1 shell space. The β-feeding has been predicted for all transitions up to about 4 MeV excitation in each daughter nucleus. The quenching of the Gamow-Teller strength has been studied by comparing the experimental strength with the calculation. The formation of the giant Gamow-Teller resonance has been studied theoretically as a function of the mass number.

  2. Cosmogenic nuclides in cometary materials: Implications for rate of mass loss and exposure history

    NASA Technical Reports Server (NTRS)

    Herzog, G. F.; Englert, P. A. J.; Reedy, R. C.

    1989-01-01

    As planned, the Rosetta mission will return to earth with a 10-kg core and a 1-kg surface sample from a comet. The selection of a comet with low current activity will maximize the chance of obtaining material altered as little as possible. Current temperature and level of activity, however, may not reliably indicate previous values. Fortunately, from measurements of the cosmogenic nuclide contents of cometary material, one may estimate a rate of mass loss in the past and perhaps learn something about the exposure history of the comet. Perhaps the simplest way to estimate the rate of mass loss is to compare the total inventories of several long-lived cosmogenic radionuclides with the values expected on the basis of model calculations. Although model calculations have become steadily more reliable, application to bodies with the composition of comets will require some extension beyond the normal range of use. In particular, the influence of light elements on the secondary particle cascade will need study, in part through laboratory irradiations of volatile-rich materials. In the analysis of cometary data, it would be valuable to test calculations against measurements of short-lived isotopes.

  3. Cosmogenic nuclide dating of Sahelanthropus tchadensis and Australopithecus bahrelghazali: Mio-Pliocene hominids from Chad

    PubMed Central

    Lebatard, Anne-Elisabeth; Bourlès, Didier L.; Duringer, Philippe; Jolivet, Marc; Braucher, Régis; Carcaillet, Julien; Schuster, Mathieu; Arnaud, Nicolas; Monié, Patrick; Lihoreau, Fabrice; Likius, Andossa; Mackaye, Hassan Taisso; Vignaud, Patrick; Brunet, Michel

    2008-01-01

    Ages were determined at two hominid localities from the Chad Basin in the Djurab Desert (Northern Chad). In the Koro Toro fossiliferous area, KT 12 locality (16°00′N, 18°53′E) was the site of discovery of Australopithecus bahrelghazali (Abel) and in the Toros-Menalla fossiliferous area, TM 266 locality (16°15′N, 17°29′E) was the site of discovery of Sahelanthropus tchadensis (Toumaï). At both localities, the evolutive degree of the associated fossil mammal assemblages allowed a biochronological estimation of the hominid remains: early Pliocene (3–3.5 Ma) at KT 12 and late Miocene (≈7 Ma) at TM 266. Atmospheric 10Be, a cosmogenic nuclide, was used to quasicontinuously date these sedimentary units. The authigenic 10Be/9Be dating of a pelite relic within the sedimentary level containing Abel yields an age of 3.58 ± 0.27 Ma that points to the contemporaneity of Australopithecus bahrelghazali (Abel) with Australopithecus afarensis (Lucy). The 28 10Be/9Be ages obtained within the anthracotheriid unit containing Toumaï bracket, by absolute dating, the age of Sahelanthropus tchadensis to lie between 6.8 and 7.2 Ma. This chronological constraint is an important cornerstone both for establishing the earliest stages of hominid evolution and for new calibrations of the molecular clock. PMID:18305174

  4. β-decay studies of nuclides in the ^100Sn region at NSCL

    NASA Astrophysics Data System (ADS)

    Lorusso, Giuseppe; Amthor, Alan; Baumann, Thomas; Bazin, Daniel; Becerril, Ana; Crawford, Heather; Estrade, Alfredo; Gade, Alexandra; Ginter, Thomas; Guess, Carol; Hausmann, Mark; Hitt, Wes; Mantica, Paul; Matos, Milan; Meharchand, Rianon; Minamisono, Kei; Montes, Fernando; Perdikakis, Giorgios; Pereira, Jorque; Pinter, Jill; Portillo, Mauritio; Schatz, Hendrik

    2008-10-01

    β-decay nuclides in the immediate neighborhood of ^100Sn, were studied at NSCL using the β-Counting system (BCS) and the Segmented Germanium Array (SeGA). The nuclei of interest were implanted into the BCS double-sided silicon strip detector and properties from both implantations and the subsequent β-decays were recorded on an event-by-event basis, allowing for the direct observation of the half-lives and the β-delayed proton emission branching ratios. The BCS also contains a stack of Si detectors and a Ge planar detector downstream of the implantation detector to measure the total energy of the emitted beta particles, and hence the β-decay end-point energy. The properties of those nuclei are not only relevant for rp-process calculations but also are essential to understand the structure of the single particle states far from the line of stability, providing stringent tests of nuclear models in this region.

  5. CRONUS-EU Cosmic Ray Produced Nuclide Systematics - The European Contribution

    NASA Astrophysics Data System (ADS)

    Dunai, T. J.; Benedetti, L.; van der Borg, K.; von Blanckenburg, F.; Ivy-Ochs, S.; Korschinek, G.; Masarik, J.; Niedermann, S.; Pik, R.; Stuart, F.; Wieler, R.; Wijbrans, J.

    2005-12-01

    The main objective of the CRONUS-EU is to advance Terrestrial cosmogenic nuclide (TCN) techniques into a robust tool for Earth surface and environmental sciences. CRONUS-EU aims to achieve this goal via: (1) High quality calibration of TCN production rates at independently dated surfaces (2) High quality calibration of TCN production rates using artificial targets (3) Systematic cross calibration of production rates of different TCNs (4) Refinement of scaling factors that describe the spatial and temporal variation of the cosmic ray flux relevant for TCN production using calibration measurements and numerical modeling from physical principles (5) Reducing the uncertainty of decay constants (6) Establishing the use of additional mineral phases in exposure age dating (7) Improvement and standardization of chemical routines (8) Laboratory cross calibrations (9) Training of young researchers and the user community The effort necessary to achieve above goal is significant even for the strong network teams in CRONUS-EU. To strengthen our effort and to achieve international evaluation and acceptance, we are seeking close collaboration with CRONUS-Earth, the parallel-running northern American sister initiative that obtained funding through NSF. Formal links between the two initiatives are established and each consortium will address complementary aspects to achieve the common goal. CRONUS-EU is a Marie-Curie Research and Training program, supported by the European Community's Program: Improving the Human Research Potential and the Socio-economic Knowledge base. www.cronus-eu.net

  6. Dual-Nuclide Radiopharmaceuticals for Positron Emission Tomography Based Dosimetry in Radiotherapy.

    PubMed

    Wurzer, Alexander; Seidl, Christof; Morgenstern, Alfred; Bruchertseifer, Frank; Schwaiger, Markus; Wester, Hans-Jürgen; Notni, Johannes

    2017-08-21

    Improvement of the accuracy of dosimetry in radionuclide therapy has the potential to increase patient safety and therapeutic outcomes. Although positron emission tomography (PET) is ideally suited for acquisition of dosimetric data because PET is inherently quantitative and offers high sensitivity and spatial resolution, it is not directly applicable for this purpose because common therapeutic radionuclides lack the necessary positron emission. This work reports on the synthesis of dual-nuclide labeled radiopharmaceuticals with therapeutic and PET functionality, which are based on common and widely available metal radionuclides. Dual-chelator conjugates, featuring interlinked cyclen- and triazacyclononane-based polyphosphinates DOTPI and TRAP, allow for strictly regioselective complexation of therapeutic (e.g., (177) Lu, (90) Y, or (213) Bi) and PET (e.g., (68) Ga) radiometals in the same molecular framework by exploiting the orthogonal metal ion selectivity of these chelators (DOTPI: large cations, such as lanthanide(III) ions; TRAP: small trivalent ions, such as Ga(III) ). Such DOTPI-TRAP conjugates were decorated with 3 Gly-urea-Lys (KuE) motifs for targeting prostate-specific membrane antigen (PSMA), employing Cu-catalyzed (CuAAC) as well as strain-promoted (SPAAC) click chemistry. These were labeled with (177) Lu or (213) Bi and (68) Ga and used for in vivo imaging of LNCaP (human prostate carcinoma) tumor xenografts in SCID mice by PET, thus proving practical applicability of the concept. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Reevaluation of the average prompt neutron emission multiplicity (nubar) values from fission of uranium and transuranium nuclides

    SciTech Connect

    Holden, N.E.; Zucker, M.S.

    1984-01-01

    In response to a need of the safeguards community, we have begun an evaluation effort to upgrade the recommended values of the prompt neutron emission multiplicity distribution, P/sub nu/ and its average value, nubar. This paper will report on progress achieved thus far. The evaluation of the uranium, plutonium, americium and curium nuclide's nubar values will be presented. The recommended values will be given and discussed. 61 references.

  8. Instrumental activation analysis of coal and fly ash with thermal and epithermal neutrons and short-lived nuclides

    USGS Publications Warehouse

    Steinnes, E.; Rowe, J.J.

    1976-01-01

    Instrumental neutron activation analysis is applied to the determination of about 25 elements in coals and fly ash by means of nuclides with half-lives of less than 48 h ; thermal and epithermal irradiations are used. The results indicate that epithermal activation is preferable for twelve of the elements (Ga, As, Br, Sr, In, Cs, Ba, La, Sm, Ho, W and U). Data for SRM 1632 (coal) and SRM 1633 (fly ash) compare favorably with the results obtained by other investigators. ?? 1976.

  9. VRF ("Visual RobFit") — nuclear spectral analysis with non-linear full-spectrum nuclide shape fitting

    NASA Astrophysics Data System (ADS)

    Lasche, George; Coldwell, Robert; Metzger, Robert

    2017-09-01

    A new application (known as "VRF", or "Visual RobFit") for analysis of high-resolution gamma-ray spectra has been developed using non-linear fitting techniques to fit full-spectrum nuclide shapes. In contrast to conventional methods based on the results of an initial peak-search, the VRF analysis method forms, at each of many automated iterations, a spectrum-wide shape for each nuclide and, also at each iteration, it adjusts the activities of each nuclide, as well as user-enabled parameters of energy calibration, attenuation by up to three intervening or self-absorbing materials, peak width as a function of energy, full-energy peak efficiency, and coincidence summing until no better fit to the data can be obtained. This approach, which employs a new and significantly advanced underlying fitting engine especially adapted to nuclear spectra, allows identification of minor peaks that are masked by larger, overlapping peaks that would not otherwise be possible. The application and method are briefly described and two examples are presented.

  10. High resolution and continuous reconstruction of Blake and Post Blake excursions using cosmogenic radio nuclides in the Antarctic ice core

    NASA Astrophysics Data System (ADS)

    Yokoyama, Y.; Tsunekawa, R.; Takahashi, S.; Miyairi, Y.; Aze, T.; Horiuchi, K.; Matsuzaki, H.; Motoyama, H.

    2015-12-01

    Geomagnetic excursions provide information on field mechanics and serve as a chronostratigraphic tool. Interpretation of sedimentological paleointensity records is complicated, and volcanic rocks provide only non-continuous records. Another means for reconstructing paleomagnetic intensity is analyzing cosmogenic radio nuclides. In this study, we reconstruct the Blake and the Post-Blake Excursions using the cosmogenic radio nuclide 10Be in the Dome Fuji ice core. It has been reported that the Blake Excursion and the Post-Blake Excursion occurred within the Brunhes Chron, at around 115 ka and 100 ka, respectively. These two excursions occurred in quick succession. The Post-Blake Excursion is relatively poorly studied, only being reconstructed from sediments and volcanic rocks. Results indicate there is a significant peaks in 10Be flux that is thought to be reflect respectively the Blake and the Post-Blake Excursions. The maximum 10Be flux during the Post-Blake Excurison is similar to that of the Blake Excursion, suggesting that the geomagnetic dipole field during the Post-Blake Excursion weakened by the same amount as during the Blake Excursion. We also compare the results for the Laschamp Excursion that we also reconstructed from the same ice core to discuss the nature of individual excursions inferred from the cosmogenic radio nuclides data.

  11. Measurements of cross sections for production of light nuclides by 120 GeV proton bombardment of Ni and Au

    NASA Astrophysics Data System (ADS)

    Okumura, Shintaro; Sekimoto, Shun; Yashima, Hiroshi; Matsushi, Yuki; Matsuzaki, Hiroyuki; Shibata, Seiichi; Ohtsuki, Tsutomu

    2014-09-01

    Production cross sections for long-lived cosmogenic nuclides, such as Be-10 and Al-26 have a very practical benefit for health and safety in radiation protection; they serve as a comprehensive nuclear database that can be used to estimate residual radioactivities in accelerator facilities. Cross sections are also indispensable for studying the specific formation mechanisms of these nuclides, where spallation, fission, or fragmentation is a dominant process. The fragmentation process is usually studied by production cross sections of light nuclides which are best measured by AMS. For energies above 100 MeV few measurements have been made and published. We have measured and report the first Be-10 and Al-26 production cross sections from Ni and Au produced by 120 GeV protons. The proton irradiation at 120 GeV was performed at Fermi National Accelerator Laboratory. The AMS measurements were performed at MALT, University of Tokyo. We will discuss the production mechanism of Be-10 and Al-26 by spallation and fragmentation.

  12. Discrete beta dose kernel matrices for nuclides applied in targeted radionuclide therapy (TRT) calculated with MCNP5

    SciTech Connect

    Reiner, Dora; Blaickner, Matthias; Rattay, Frank

    2009-11-15

    Purpose: Radiopharmaceuticals administered in targeted radionuclide therapy (TRT) rely to a great extent not only on beta-emitting nuclides but also on emitters of monoenergetic electrons. Recent advances like combined PET/CT devices, the consequential coregistration of both data, the concept of using beta couples for diagnosis and therapy, respectively, as well as the development of voxel models offer a great potential for developing TRT dose calculation systems similar to those available for external beam treatment planning. The deterministic algorithms in question for this task are based on the convolution of three-dimensional matrices, one representing the activity distribution and the other the dose point kernel. This study aims to report on three-dimensional kernel matrices for various nuclides used in TRT. Methods: The Monte Carlo code MCNP5 was used to calculate discrete dose kernels of beta particles including the contributions from their respective secondary radiation in soft tissue for the following nuclides: {sup 32}P, {sup 33}P, {sup 67}Cu, {sup 89}Sr, {sup 90}Y, {sup 103}Rh{sup m}, {sup 131}I, {sup 177}Lu, {sup 186}Re, and {sup 188}Re. For each nuclide a kernel cube of 10x10x10 mm{sup 3} was calculated, the dimensions of a voxel being 1 mm{sup 3}. Additional kernels with voxel sizes of 3x3x3 mm{sup 3} were simulated. Results: Comparison with the S-value data regarding {sup 32}P, {sup 89}Sr, {sup 90}Y, and {sup 131}I of the MIRD committee which were calculated with the EGS4 code showed a very good agreement, the secondary particle transport of {sup 90}Y being the only exception. Documented analytical kernels on the other side show deviations very close and very far to the source. Conclusions: The good accordance with the only discrete dose kernels published up to date justifies the method chosen. Together with the additional six nuclides, this report provides a considerable database for three-dimensional kernel matrices with regard to beta

  13. Extensive MIS 3 glaciation in southernmost Patagonia revealed by cosmogenic nuclide dating of outwash sediments

    NASA Astrophysics Data System (ADS)

    Darvill, Christopher M.; Bentley, Michael J.; Stokes, Chris R.; Hein, Andrew S.; Rodés, Ángel

    2015-11-01

    The timing and extent of former glacial advances can demonstrate leads and lags during periods of climatic change and their forcing, but this requires robust glacial chronologies. In parts of southernmost Patagonia, dating pre-global Last Glacial Maximum (gLGM) ice limits has proven difficult due to post-deposition processes affecting the build-up of cosmogenic nuclides in moraine boulders. Here we provide ages for the Río Cullen and San Sebastián glacial limits of the former Bahía Inútil-San Sebastián (BI-SSb) ice lobe on Tierra del Fuego (53-54°S), previously hypothesised to represent advances during Marine Isotope Stages (MIS) 12 and 10, respectively. Our approach uses cosmogenic 10Be and 26Al exposure dating, but targets glacial outwash associated with these limits and uses depth-profiles and surface cobble samples, thereby accounting for surface deflation and inheritance. The data reveal that the limits formed more recently than previously thought, giving ages of 45.6 ka (+139.9/-14.3) for the Río Cullen, and 30.1 ka (+45.6/-23.1) for the San Sebastián limits. These dates indicate extensive glaciation in southern Patagonia during MIS 3, prior to the well-constrained, but much less extensive MIS 2 (gLGM) limit. This suggests the pattern of ice advances in the region was different to northern Patagonia, with the terrestrial limits relating to the last glacial cycle, rather than progressively less extensive glaciations over hundreds of thousands of years. However, the dates are consistent with MIS 3 glaciation elsewhere in the southern mid-latitudes, and the combination of cooler summers and warmer winters with increased precipitation, may have caused extensive glaciation prior to the gLGM.

  14. Constraining Landscape History and Glacial Erosivity Using Paired Cosmogenic Nuclides in Upernavik, Northwest Greenland

    NASA Technical Reports Server (NTRS)

    Corbett, Lee B.; Bierman, Paul R.; Graly, Joseph A.; Neumann, Thomas A.; Rood, Dylan H.

    2013-01-01

    High-latitude landscape evolution processes have the potential to preserve old, relict surfaces through burial by cold-based, nonerosive glacial ice. To investigate landscape history and age in the high Arctic, we analyzed in situ cosmogenic Be(sup 10) and Al (sup 26) in 33 rocks from Upernavik, northwest Greenland. We sampled adjacent bedrock-boulder pairs along a 100 km transect at elevations up to 1000 m above sea level. Bedrock samples gave significantly older apparent exposure ages than corresponding boulder samples, and minimum limiting ages increased with elevation. Two-isotope calculations Al(sup26)/B(sup 10) on 20 of the 33 samples yielded minimum limiting exposure durations up to 112 k.y., minimum limiting burial durations up to 900 k.y., and minimum limiting total histories up to 990 k.y. The prevalence of BE(sup 10) and Al(sup 26) inherited from previous periods of exposure, especially in bedrock samples at high elevation, indicates that these areas record long and complex surface exposure histories, including significant periods of burial with little subglacial erosion. The long total histories suggest that these high elevation surfaces were largely preserved beneath cold-based, nonerosive ice or snowfields for at least the latter half of the Quaternary. Because of high concentrations of inherited nuclides, only the six youngest boulder samples appear to record the timing of ice retreat. These six samples suggest deglaciation of the Upernavik coast at 11.3 +/- 0.5 ka (average +/- 1 standard deviation). There is no difference in deglaciation age along the 100 km sample transect, indicating that the ice-marginal position retreated rapidly at rates of approx.120 m yr(sup-1).

  15. Cosmogenic Nuclide Surficial Age Comparison between Boulders and Desert Pavement in the Mojave Desert, California

    NASA Astrophysics Data System (ADS)

    Blumentritt, D.; Perg, L. A.; Oskin, M. E.

    2005-12-01

    Cosmogenic nuclides can be an effective way to analyze surface ages when proper sampling strategies are employed given the depositional environment, erosion history, and approximate age of the surface. Recent cosmogenic dating work was performed on the Sheep Springs Wash alluvial terraces in the Rodman Mountains, Mojave Desert, California. Clast types on the terraces are predominantly quartz monzonite and basalt. Sampling strategies primarily included the tops of boulders (40-120 cm in diameter), which are thought to be the best representation of surface exposure ages. Complimentary surface samples were also collected from the incipient desert pavement for comparison to boulder ages. Desert pavement clasts were slightly angular, some with flat faces, and some with stream-rounded edges. 10Be concentration ages measured from quartz monzonite boulders and amalgamated desert pavement clasts have similar values where the average ages are 58.7 ka and 55.4 ka, respectively, and the maximum ages are nearly identical (63.4 and 63.2 ka), with the greatest discrepancy in the minimum ages of 56.0 ka (boulder) and 48.5 ka (pavement). These ages indicate two possible pavement clast sources, (1) they are from the original stream channel deposit, or (2) they are the result of boulder spalling. Given that many of the pavement surfaces are located in low boulder density areas, contain a wide variety of clast types, including spallation-resistant basalt, and pavement ages are not consistently higher than boulder ages, our contention is that the desert pavement is primarily derived from small clasts deposited on the surface just prior to its abandonment. Contamination of desert pavement samples from clasts exhumed from deeper in the terrace does not appear to have significantly altered its age. Desert pavements may be more attractive to sample because they are far less strenuous and time consuming to collect.

  16. Feasibility study for transuranic nuclide measurement on long-length contaminated equipment using neutron detection

    SciTech Connect

    Stromswold, D.C.; Peurrung, A.J.; Arthur, R.J.

    1995-10-01

    The feasibility of measuring the transuranic (TRU) nuclide content of equipment removed from Hanford`s high-level radioactive-waste tanks has been established for components heavier than about 30 kg/m (20 lbs/ft). This conclusion has been reached based on experience with the TRU assay of waste burial boxes, planned improvements to the assay equipment design and assay methodology, and experimental investigation of neutron detector performance in high gamma-ray fields. The experiments indicate that the neutron detectors presently used with Pacific Northwest Laboratory`s box scanner perform correctly in gamma-ray exposure rates of at least 3 R/h. The design of equipment proposed for measuring TRU content incorporates multiple, BF{sub 3}-gas-filled neutron counters in a configuration that is approximately 0.5 m wide and 2 m long, with polyethylene to moderate high-energy neutrons down to thermal energy. Specially developed electrical systems are used to eliminate response to gamma-rays. Performance of the assay would require 10 to 14 hours of time during which close-range access is provided to the waste and its burial container. A standard neutron source, will be placed within the burial container (before inserting components) to allow calibration of the detector. Final calculation of the TRU contamination will utilize plausible conservative assumptions concerning the spatial, isotopic, and elemental distributions of any TRU present. For long-length equipment, the detector array collects data at various positions along the length of the equipment. Separate monitoring of the cosmic-ray-induced neutron background during the assay period will provide confidence that observed changes in counts at the equipment are not related to changing background. Background measurements using the burial container and equipment {open_quotes}skid{close_quotes} will allow compensation for neutrons that are created by cosmic-ray spallation within the burial container.

  17. Fission barriers at the end of the chart of the nuclides

    SciTech Connect

    Möller, Peter; Sierk, Arnold J.; Ichikawa, Takatoshi; Iwamoto, Akira; Mumpower, Matthew

    2015-02-12

    We present calculated fission-barrier heights for 5239 nuclides for all nuclei between the proton and neutron drip lines with 171 ≤ A ≤ 330. The barriers are calculated in the macroscopic-microscopic finite-range liquid-drop (FRLDM) with a 2002 set of macroscopic-model parameters. The saddle-point energies are determined from potential-energy surfaces based on more than five million different shapes, defined by five deformation parameters in the three-quadratic-surface shape parametrization: elongation, neck diameter, left-fragment spheroidal deformation, right-fragment spheroidal deformation, and nascent-fragment mass asymmetry. The energy of the ground state is determined by calculating the lowest-energy configuration in both the Nilsson perturbed-spheroid (ϵ) and the spherical-harmonic (β) parametrizations, including axially asymmetric deformations. The lower of the two results (correcting for zero-point motion) is defined as the ground-state energy. The effect of axial asymmetry on the inner barrier peak is calculated in the (ϵ,γ) parametrization. We have earlier benchmarked our calculated barrier heights to experimentally extracted barrier parameters and found average agreement to about one MeV for known data across the nuclear chart. Here we do additional benchmarks and investigate the qualitative and, when possible, quantitative agreement and/or consistency with data on β-delayed fission, isotope generation along prompt-neutron-capture chains in nuclear-weapons tests, and superheavy-element stability. In addition these studies all indicate that the model is realistic at considerable distances in Z and N from the region of nuclei where its parameters were determined.

  18. Fission barriers at the end of the chart of the nuclides

    NASA Astrophysics Data System (ADS)

    Möller, Peter; Sierk, Arnold J.; Ichikawa, Takatoshi; Iwamoto, Akira; Mumpower, Matthew

    2015-02-01

    We present calculated fission-barrier heights for 5239 nuclides for all nuclei between the proton and neutron drip lines with 171 ≤A ≤330 . The barriers are calculated in the macroscopic-microscopic finite-range liquid-drop model with a 2002 set of macroscopic-model parameters. The saddle-point energies are determined from potential-energy surfaces based on more than 5 000 000 different shapes, defined by five deformation parameters in the three-quadratic-surface shape parametrization: elongation, neck diameter, left-fragment spheroidal deformation, right-fragment spheroidal deformation, and nascent-fragment mass asymmetry. The energy of the ground state is determined by calculating the lowest-energy configuration in both the Nilsson perturbed-spheroid (ɛ ) and the spherical-harmonic (β ) parametrizations, including axially asymmetric deformations. The lower of the two results (correcting for zero-point motion) is defined as the ground-state energy. The effect of axial asymmetry on the inner barrier peak is calculated in the (ɛ ,γ ) parametrization. We have earlier benchmarked our calculated barrier heights to experimentally extracted barrier parameters and found average agreement to about 1 MeV for known data across the nuclear chart. Here we do additional benchmarks and investigate the qualitative and, when possible, quantitative agreement and/or consistency with data on β -delayed fission, isotope generation along prompt-neutron-capture chains in nuclear-weapons tests, and superheavy-element stability. These studies all indicate that the model is realistic at considerable distances in Z and N from the region of nuclei where its parameters were determined.

  19. Removal of Radioactive Nuclides from Mo-99 Acidic Liquid Waste - 13027

    SciTech Connect

    Hsiao, Hsien-Ming; Pen, Ben-Li

    2013-07-01

    About 200 liters highly radioactive acidic liquid waste originating from Mo-99 production was stored at INER (Institute of Nuclear Energy Research). A study regarding the treatment of the radioactive acidic liquid waste was conducted to solve storage-related issues and allow discharge of the waste while avoiding environmental pollution. Before discharging the liquid waste, the acidity, NO{sub 3}{sup -} and Hg ions in high concentrations, and radionuclides must comply with environmental regulations. Therefore, the treatment plan was to neutralize the acidic liquid waste, remove key radionuclides to reduce the dose rate, and then remove the nitrate and mercury ions. Bench tests revealed that NaOH is the preferred solution to neutralize the high acidic waste solution and the pH of solution must be adjusted to 9∼11 prior to the removal of nuclides. Significant precipitation was produced when the pH of solution reached 9. NaNO{sub 3} was the major content in the precipitate and part of NaNO{sub 3} was too fine to be completely collected by filter paper with a pore size of approximately 3 μm. The residual fine particles remaining in solution therefore blocked the adsorption column during operation. Two kinds of adsorbents were employed for Cs-137 and a third for Sr-90 removal to minimize cost. For personnel radiation protection, significant lead shielding was required at a number of points in the process. The final process design and treatment facilities successfully treated the waste solutions and allowed for environmentally compliant discharge. (authors)

  20. On a solar origin for the cosmogenic nuclide event of 775 A.D

    SciTech Connect

    Cliver, E. W.; Tylka, A. J.; Dietrich, W. F.; Ling, A. G.

    2014-01-20

    We explore requirements for a solar particle event (SPE) and flare capable of producing the cosmogenic nuclide event of 775 A.D., and review solar circumstances at that time. A solar source for 775 would require a >1 GV spectrum ∼45 times stronger than that of the intense high-energy SPE of 1956 February 23. This implies a >30 MeV proton fluence (F {sub 30}) of ∼8 × 10{sup 10} proton cm{sup –2}, ∼10 times larger than that of the strongest 3 month interval of SPE activity in the modern era. This inferred F {sub 30} value for the 775 SPE is inconsistent with the occurrence probability distribution for >30 MeV solar proton events. The best guess value for the soft X-ray classification (total energy) of an associated flare is ∼X230 (∼9 × 10{sup 33} erg). For comparison, the flares on 2003 November 4 and 1859 September 1 had observed/inferred values of ∼X35 (∼10{sup 33} erg) and ∼X45 (∼2 × 10{sup 33} erg), respectively. The estimated size of the source active region for a ∼10{sup 34} erg flare is ∼2.5 times that of the largest region yet recorded. The 775 event occurred during a period of relatively low solar activity, with a peak smoothed amplitude about half that of the second half of the 20th century. The ∼1945-1995 interval, the most active of the last ∼2000 yr, failed to witness a SPE comparable to that required for the proposed solar event in 775. These considerations challenge a recent suggestion that the 775 event is likely of solar origin.

  1. Cosmogenic nuclide evidence for low weathering and denudation in the wet, tropical highlands of Sri Lanka

    NASA Astrophysics Data System (ADS)

    von Blanckenburg, Friedhelm; Hewawasam, Tilak; Kubik, Peter W.

    2004-09-01

    Some of the lowest weathering and erosion rates in any mountain range in the world have been measured using cosmogenic nuclides in the steep, humid, tropical highlands of Sri Lanka. The total preanthropogenic denudation rates were measured in creek sediments and soil samples from unperturbed rain forest sites, bedrock from mountain crests, and bedrock from inselbergs. Denudation rates are in the range of 5-30 t km-2 yr-1 (2-11 mm ky-1). These rates average denudation over the last 50-250 ky. Weathering exports in rivers draining the mountainous Central Highlands show that silicate weathering rates are also low, varying from 5 to 20 t km-2 yr-1 today (2-7 mm ky-1), but they represent a significant fraction of the total denudation. All these observations run contrary to the conventional geomorphologic and geochemical wisdom that would predict rapid erosion for highlands of high relief, temperatures, and precipitation. We speculate that the high relief in Sri Lanka represents the remnant of a geomorphic block that was uplifted during rifting at 130 Ma or even earlier and that was reduced to the interior of the island by rapid receding of escarpments after continental breakup. It is possible that throughout this history, hillslopes, where not exposing bare bedrock, were protected by thick weathered profiles. Such clay-rich layers would inhibit silicate weathering by shielding bedrock from weathering agents. In the absence of landscape rejuvenation, physical erosion rates are low, and fresh mineral surfaces are not being supplied. The observation that wet, steep, tropical highlands can have low rates of rock weathering and erosion has some potentially profound implications for the long-term controls of atmospheric CO2 budgets: High temperature and precipitation, which are much invoked though controversial agents for silicate dissolution and CO2 drawdown, become ineffective in promoting weathering in areas that are not tectonically active.

  2. Fission barriers at the end of the chart of the nuclides

    DOE PAGES

    Möller, Peter; Sierk, Arnold J.; Ichikawa, Takatoshi; ...

    2015-02-12

    We present calculated fission-barrier heights for 5239 nuclides for all nuclei between the proton and neutron drip lines with 171 ≤ A ≤ 330. The barriers are calculated in the macroscopic-microscopic finite-range liquid-drop (FRLDM) with a 2002 set of macroscopic-model parameters. The saddle-point energies are determined from potential-energy surfaces based on more than five million different shapes, defined by five deformation parameters in the three-quadratic-surface shape parametrization: elongation, neck diameter, left-fragment spheroidal deformation, right-fragment spheroidal deformation, and nascent-fragment mass asymmetry. The energy of the ground state is determined by calculating the lowest-energy configuration in both the Nilsson perturbed-spheroid (ϵ) andmore » the spherical-harmonic (β) parametrizations, including axially asymmetric deformations. The lower of the two results (correcting for zero-point motion) is defined as the ground-state energy. The effect of axial asymmetry on the inner barrier peak is calculated in the (ϵ,γ) parametrization. We have earlier benchmarked our calculated barrier heights to experimentally extracted barrier parameters and found average agreement to about one MeV for known data across the nuclear chart. Here we do additional benchmarks and investigate the qualitative and, when possible, quantitative agreement and/or consistency with data on β-delayed fission, isotope generation along prompt-neutron-capture chains in nuclear-weapons tests, and superheavy-element stability. In addition these studies all indicate that the model is realistic at considerable distances in Z and N from the region of nuclei where its parameters were determined.« less

  3. On a Solar Origin for the Cosmogenic Nuclide Event of 775 A.D.

    NASA Technical Reports Server (NTRS)

    Cliver, E. W.; Tylka, A. J.; Dietrich, W. F.; Ling, A. G.

    2014-01-01

    We explore requirements for a solar particle event (SPE) and flare capable of producing the cosmogenic nuclide event of 775 A.D., and review solar circumstances at that time. A solar source for 775 would require a greater than 1 GV spectrum approximately 45 times stronger than that of the intense high-energy SPE of 1956 February 23. This implies a greater than 30 MeV proton fluence (F(sub 30)) of approximately 8 × 10(exp 10) proton cm(exp -2), approximately 10 times larger than that of the strongest 3 month interval of SPE activity in the modern era. This inferred F(sub 30) value for the 775 SPE is inconsistent with the occurrence probability distribution for greater than 30 MeV solar proton events. The best guess value for the soft X-ray classification (total energy) of an associated flare is approximately X230 (approximately 9 × 10(exp 33) erg). For comparison, the flares on 2003 November 4 and 1859 September 1 had observed/inferred values of approximately X35 (approximately 10(exp 33) erg) and approximately X45 (approximately 2 × 10(exp 33) erg), respectively. The estimated size of the source active region for a approximately 10(exp 34) erg flare is approximately 2.5 times that of the largest region yet recorded. The 775 event occurred during a period of relatively low solar activity, with a peak smoothed amplitude about half that of the second half of the 20th century. The approximately 1945-1995 interval, the most active of the last approximately 2000 yr, failed to witness a SPE comparable to that required for the proposed solar event in 775. These considerations challenge a recent suggestion that the 775 event is likely of solar origin.

  4. Deglacial history of the Pensacola Mountains, Antarctica from glacial geomorphology and cosmogenic nuclide surface exposure dating

    NASA Astrophysics Data System (ADS)

    Bentley, M. J.; Hein, A. S.; Sugden, D. E.; Whitehouse, P. L.; Shanks, R.; Xu, S.; Freeman, S. P. H. T.

    2017-02-01

    The retreat history of the Antarctic Ice Sheet is important for understanding rapid deglaciation, as well as to constrain numerical ice sheet models and ice loading models required for glacial isostatic adjustment modelling. There is particular debate about the extent of grounded ice in the Weddell Sea embayment at the Last Glacial Maximum, and its subsequent deglacial history. Here we provide a new dataset of geomorphological observations and cosmogenic nuclide surface exposure ages of erratic samples that constrain the deglacial history of the Pensacola Mountains, adjacent to the present day Foundation Ice Stream and Academy Glacier in the southern Weddell Sea embayment. We show there is evidence of at least two glaciations, the first of which was relatively old and warm-based, and a more recent cold-based glaciation. During the most recent glaciation ice thickened by at least 450 m in the Williams Hills and at least 380 m on Mt Bragg. Progressive thinning from these sites was well underway by 10 ka BP and ice reached present levels by 2.5 ka BP, and is broadly similar to the relatively modest thinning histories in the southern Ellsworth Mountains. The thinning history is consistent with, but does not mandate, a Late Holocene retreat of the grounding line to a smaller-than-present configuration, as has been recently hypothesized based on ice sheet and glacial isostatic modelling. The data also show that clasts with complex exposure histories are pervasive and that clast recycling is highly site-dependent. These new data provide constraints on a reconstruction of the retreat history of the formerly-expanded Foundation Ice Stream, derived using a numerical flowband model.

  5. Heavy Rescue - Course Outline.

    DTIC Science & Technology

    1980-11-01

    used during heavy rescue operations . Methods and procedures for utilizing heavy rescue equipment. 4 Methods of developing improvised rescue equipment...utilizing available materials. A simulated exercise utilizing various rescue operations and techniques. Methods and procedures for the maintenance and...HEAVY RESCUE CONSIDERATIONS LEVEL I PERFORMANCE GOALS: 1 Hour GIVEN: 1. Summary of blocked access considerations during heavy rescue operations 2

  6. Heavy-ion radiotherapy

    NASA Astrophysics Data System (ADS)

    Kanai, Tatsuaki

    2000-11-01

    Heavy-ion radiotherapy using high-energy carbon beams has been performed at the National Institute of Radiological Sciences, Japan. The physical frame works for heavy-ion radiotherapy are established using physical understandings of radiation physics. In order to increase the accuracy of heavy-ion radiotherapy, many physical problems should be solved. Unsolved problems, such as the depth dose distributions, range of heavy-ion in patients and heavy-ion dosimetry in the radiation therapy, are discussed. .

  7. Thick-Target Simulation Experiments as a Basis for Consistent Modeling of Cosmogenic Nuclide Production in Extraterrestrial Matter

    NASA Astrophysics Data System (ADS)

    Michel, R.; Lange, H.-J.; Leya, I.; Herpers, U.; Meltzow, B.; Dittrich-Hannen, B.; Suter, M.; Kubik, P. W.

    1995-09-01

    Cosmogenic nuclide production rates in meteoroids depend on size and bulk chemical composition of the meteoroid, on the shielding depth and the chemical composition of a sample in it, on spectral distribution, composition and intensity of solar and galactic cosmic radiation, and on the possibly complex exposure history. Except for bulk and sample chemical compositions, all parameters are unknown and must be reconstructed. In order to interpret cosmogenic nuclide abundances in meteorites with respect to their exposure histories, to reconstruct the preatmospheric shapes of the meteoroids and to draw conclusions about long-term spectral distributions and intensities of the cosmic radiation, reliable model calculations of producton rates must be available. The lack of knowledge about the parameters which influence the production rates causes ambiguity of empirical and physical model calculations, if exclusively meteorite data are taken into account. Physical models of cosmogenic nuclide production in meteoroids without free parameters can be established on the basis of thick-target experiments by which the cosmic ray exposure of meteoroids in space is simulated as close as possible under completely controlled conditions. During recent years, we have performed five such experiments to simulate the exposure of meteoroids to galactic protons [1-6]. Here, we report new results on the latest one of these experiments, in which an artificial iron meteoroid made of steel with a radius of 10 cm was isotropically irradiated by 1.6 GeV protons [4,5]. Measurements and evaluation are now completed for shortand mediumlived radionuclides. Results for long-lived nuclides by AMS and of stable rare gas isotopes are partially available with additional measurements still going on. The results obtained up to now for radionuclide production are presented and discussed with respect to some aspects of the production of cosmogenic nuclides in iron meteoroids and of the influence of bulk

  8. Nuclide analysis in high burnup fuel samples irradiated in Vandellós 2

    NASA Astrophysics Data System (ADS)

    Zwicky, H. U.; Low, J.; Granfors, M.; Alejano, C.; Conde, J. M.; Casado, C.; Sabater, J.; Lloret, M.; Quecedo, M.; Gago, J. A.

    2010-07-01

    In the framework of a high burnup fuel demonstration programme, rods with an enrichment of 4.5% 235U were operated to a rod average burnup of about 70 MWd/kgU in the Spanish Vandellós 2 pressurised water reactor. The rods were sent to hot cells and used for different research projects. This paper describes the isotopic composition measurements performed on samples of those rods, and the analysis of the measurement results based on comparison against calculated values. The fraction and composition of fission gases released to the rod free volume was determined for two of the rods. About 8% of Kr and Xe produced by fission were released. From the isotopic composition of the gases, it could be concluded that the gases were not preferentially released from the peripheral part of the fuel column. Local burnup and isotopic content of gamma emitting nuclides were determined by quantitatively evaluating axial gamma scans of the full rods. Nine samples were cut at different axial levels from three of the rods and analysed in two campaigns. More than 50 isotopes of 16 different elements were assessed, most of them by Inductively Coupled Plasma Mass Spectrometry after separation with High Performance Liquid Chromatography. In general, these over 400 data points gave a consistent picture of the isotopic content of irradiated fuel as a function of burnup. Only in a few cases, the analysis provided unexpected results that seem to be wrong, in most cases due to unidentified reasons. Sample burnup analysis was performed by comparing experimental isotopic abundances of uranium and plutonium composition as well as neodymium isotopic concentrations with corresponding CASMO based data. The results were in agreement with values derived independently from gamma scanning and from core design data and plant operating records. Measured isotope abundances were finally assessed using the industry standard SAS2H sequence of the SCALE code system. This exercise showed good agreement between

  9. The Light Curve of SN 1987A Revisited: Constraining Production Masses of Radioactive Nuclides

    NASA Astrophysics Data System (ADS)

    Seitenzahl, Ivo R.; Timmes, F. X.; Magkotsios, Georgios

    2014-09-01

    We revisit the evidence for the contribution of the long-lived radioactive nuclides 44Ti, 55Fe, 56Co, 57Co, and 60Co to the UVOIR light curve of SN 1987A. We show that the V-band luminosity constitutes a roughly constant fraction of the bolometric luminosity between 900 and 1900 days, and we obtain an approximate bolometric light curve out to 4334 days by scaling the late time V-band data by a constant factor where no bolometric light curve data is available. Considering the five most relevant decay chains starting at 44Ti, 55Co, 56Ni, 57Ni, and 60Co, we perform a least squares fit to the constructed composite bolometric light curve. For the nickel isotopes, we obtain best fit values of M(56Ni) = (7.1 ± 0.3) × 10-2 M ⊙ and M(57Ni) = (4.1 ± 1.8) × 10-3 M ⊙. Our best fit 44Ti mass is M(44Ti) = (0.55 ± 0.17) × 10-4 M ⊙, which is in disagreement with the much higher (3.1 ± 0.8) × 10-4 M ⊙ recently derived from INTEGRAL observations. The associated uncertainties far exceed the best fit values for 55Co and 60Co and, as a result, we only give upper limits on the production masses of M(55Co) < 7.2 × 10-3 M ⊙ and M(60Co) < 1.7 × 10-4 M ⊙. Furthermore, we find that the leptonic channels in the decay of 57Co (internal conversion and Auger electrons) are a significant contribution and constitute up to 15.5% of the total luminosity. Consideration of the kinetic energy of these electrons is essential in lowering our best fit nickel isotope production ratio to [57Ni/56Ni] = 2.5 ± 1.1, which is still somewhat high but is in agreement with gamma-ray observations and model predictions.

  10. Morphologic features and nuclide composition of infarction-associated cardiac myocyte mineralization in humans.

    PubMed Central

    Lockard, V. G.; Bloom, S.

    1991-01-01

    Low dietary Mg results in Ca loading of cardiac myocytes, which increases the likelihood of myocyte calcification in the event of acute myocardial infarction (AMI), and possibly increases myocyte vulnerability to necrosis. Bloom and Peric-Golia1 previously reported an autopsy study of cases from the Washington, D.C. area (a region with low levels of Mg in the drinking water), demonstrating AMI-associated mineralization in myocytes with histologically normal nuclei and cross striations, as well as in obviously necrotic myocytes. The authors have re-examined mineralized myocytes from the same autopsy material, using electron probe microanalysis, light microscopy, and transmission electron microscopy. Microprobe analysis identified Ca and P as the nuclides composing the inorganic phase of the mineral deposits. Ultrastructurally, all Ca deposits, regardless of size or intracellular location, were composed of aggregates of needlelike hydroxyapatite crystals. The mildest form of intracellular Ca deposition was observed as small Ca deposits limited to some mitochondria of myocytes, which demonstrated intact nuclei and regular sarcomere pattern. More advanced stages of intracellular calcification, in the form of Ca deposits associated with mitochondria, Z-band regions and nuclei, were observed in other myocytes that also retained intact nuclei and sarcomeres. Massive Ca deposits were associated with myocytes which showed morphologic features of advanced necrosis, including loss of nuclei, disruption of sarcomere structure and masses of cellular debris. These observations support the theory originally proposed by Bloom and Peric-Golia1 suggesting that Ca loading of myocytes, possibly related to Mg deficiency in humans, increased vulnerability of the myocytes to subsequent AMI-associated necrosis and dystrophic calcification. In addition, the light microscopic impression of calcification of otherwise normal myocytes is contradicted by the electron microscopic identification

  11. The Gas-Filled-Magnet at PRIME Lab: Increased Sensitivity of Cosmogenic Nuclide Measurements

    NASA Astrophysics Data System (ADS)

    Caffee, M. W.; Granger, D. E.; Woodruff, T. E.

    2015-12-01

    Abstract: Using accelerator mass spectrometry (AMS), radionuclides produced either by cosmic-ray interactions or by nucleogenic means can be measured. Typical isotopic abundance ratios range from 1 x 10-10 to 1 x 10-15. The routinely measured radionuclides are 10Be, 14C, 26Al, 36Cl, and 129I. Be-10, 26Al, and 36Cl have isobaric interferences that cannot be eliminated mass through mass analysis, but dE/dx techniques suppresses these isobars enough to allow successful measurements. There are compromises, the isobar for 26Al, 26Mg, precludes successful measurement of 26Al if AlO- is injected into the accelerator. Mg- doesn't form a stable negative ion so a 26Al measurement requires injection of 26Al-. But the Al- ion is formed inefficiently; secondary ion currents using Al- are ~ 10 times less than an AlO- secondary ion beam. Precision scales with count rate so precise measurement of the 26Al/Al for all but higher ratio samples is difficult. It has long been recognized that a gas-filled-magnet (GFM) could potentially improve the measurement of those radionuclides with intractable isobar interferences. A GFM works on the principle that each element of an isobar pair, e.g. 26Mg and 26Al, has a different average charge state as it traverses a gas (3-4 Torr of N2) contained within the vacuum jacket of a magnet. The magnet steers each species with its own momentum-to-charge ratio on its own distinct radius of curvature. The magnet can be tuned to allow the isotope of interest into a dE/dx detector; most of the isobar doesn't make it into the detector. Using the PRIME Lab GFM we are now able to routinely run 26Al with a precision that is comparable to that obtained with 10Be. We are also using the GFM for routine measurements of 10Be and 36Cl. Although the improvement for these nuclides is not as pronounced as it is for 26Al, the GFM has improved the detection sensitivity for both. Our 10Be background is now ~ 5 x 10-16 and for 36Cl we can now run the source more

  12. Boulder, Pavement, Pit; Sample Selection for Cosmogenic Nuclide Dating on Alluvial Fans

    NASA Astrophysics Data System (ADS)

    Perg, L. A.; Oskin, M. E.; Blumentritt, D.; Strane, M.; Mukhopadhyay, S.

    2005-12-01

    Selecting sample targets and methods that minimize the effects of erosion, inheritance, and material movement is one of the largest issues facing cosmogenic isotope dating. Since sample material availability often sharply limits methods, establishing error estimates in less-than-ideal sampling situations is also important. Our study of alluvial fan offsets in the Eastern California Shear Zone (Mojave Desert) takes advantage of multiple sample targets to develop method inter-comparisons. Alluvial fans along the Calico fault had abundant large basalt and quartz monzonite boulders, targets for 3He and 10Be respectively. In addition to the boulders, the incipient desert pavement on the youngest alluvial fan surface was sampled. The basalt boulders had higher relative cosmogenic nuclide concentrations, and a much higher scatter, due to very high inheritance and also likely boulder recycling into younger terraces. The quartz monzonite had lower, consistent concentrations on the youngest terrace, but presented erosional concerns due to the spalling and grussification common to granitic material. The incipient desert pavement had a comparable 10Be concentration to the quartz monzonite boulders; the highest concentration in each was the same, and the average pavement concentration lagged the boulders only slightly. The Lenwood fault alluvial fans had two targets. Small clasts formed weakly developed to mature pavement on the surfaces. The fan deposits were also thick enough to dig pits (1.5m). On the younger fan surface, both sediment and clasts (gravel to cobble) were collected in the pit; concentrations were comparable between the two. The profiles indicated high inheritance (comparable to modern wash samples), and some mixing at the near surface. Due to high inheritance, the surface sample alone would far overestimate the age. Using wash samples to estimate inheritance slightly overcorrects, due to mixing in the near-surface. Two types of clasts were sampled in the older

  13. Beryllium-10 terrestrial cosmogenic nuclide surface exposure dating of Quaternary landforms in Death Valley

    NASA Astrophysics Data System (ADS)

    Owen, Lewis A.; Frankel, Kurt L.; Knott, Jeffrey R.; Reynhout, Scott; Finkel, Robert C.; Dolan, James F.; Lee, Jeffrey

    2011-02-01

    Quaternary alluvial fans, and shorelines, spits and beach bars were dated using 10Be terrestrial cosmogenic nuclide (TCN) surface exposure methods in Death Valley. The 10Be TCN ages show considerable variance on individual surfaces. Samples collected in the active channels date from ~ 6 ka to ~ 93 ka, showing that there is significant 10Be TCN inheritance within cobbles and boulders. This suggests that the predominantly bedrock hillslopes erode very slowly and sediment is transferred very gradually in most regions within Death Valley. Comparisons of 10Be TCN ages on alluvial fan surfaces with chronostratigraphies based on soil development and optically stimulated luminescence dating show that minimum 10Be TCN ages within sample sets on individual surfaces most closely approximate to the age of landforms that are younger than ~ 70 ka. Alluvial fan surfaces older than ~ 70 ka have begun to undergo sufficient erosion such that the majority of 10Be TCN ages for datasets on individual surfaces probably underestimate the true age of the surface due to erosion and exhumation of fresh cobbles and boulders. The spread of 10Be TCN ages for beach bars near Beatty Junction and shorelines ~ 8 km south of Furnace Creek is large, ranging from ~ 119 ka to ~ 385 ka and ~ 109 ka to ~ 465 ka, respectively. New and previously published luminescence ages and soil development suggest that these landforms may have formed during marine isotope stage (MIS) 2 (~ 22-18 ka), but these younger ages may reflect elluviation of material into the bar deposit long after deposition, and hence the younger ages do not record the true antiquity of the landforms. This disparity between dates determined by different dating methods and the large spread of TCN ages suggests that the cobbles and boulders have considerable inherited 10Be concentrations, suggesting that the clasts have been derived from older shorelines or associated landforms. These results highlight the problems associated with using

  14. Cosmogenic Nuclide Exposure Dating of the Tiltill Rock Avalanche, Yosemite National Park

    NASA Astrophysics Data System (ADS)

    Ford, K. R.; Pluhar, C. J.; Stone, J. O.; Stock, G. M.; Zimmerman, S. R.

    2013-12-01

    Yosemite National Park serves as an excellent natural laboratory for studying rock falls and rock avalanches because these are the main processes modifying the nearly vertical slopes of this recently glaciated landscape. Mass wasting represents a significant hazard in the region and the database of previous rock falls and other mass wasting events in Yosemite is extensive, dating back to the mid-1800s. However, this record is too short to capture the recurrence characteristics and triggering mechanisms of the very largest events, necessitating studies of the geologic record of mass wasting. Rock falls and rock avalanches are readily dated by cosmogenic nuclide methods due to their instantaneous formation, and results can be tied to triggering events such as seismic activity (e.g. Stock et al., 2009). Here, we apply exposure dating to the Holocene Tiltill rock avalanche north of Hetch Hetchy Reservoir. The deposit comprises what appear to be two separate lobes of rock and debris, yielding a total volume of ~3.1 x 106 m3. Assuming an erosion rate of 0.0006 cm/yr and neglecting snowpack shielding, preliminary data suggest a mean exposure age of 11,000 + 600 year B.P. for both deposits, indicating that they were emplaced in a single event. The age of the Tiltill 'slide' is similar to earthquakes on the Owens Valley Fault between 10,800 + 600 and 10,200 + 200 cal year B.P. (Bacon, 2007) and the White Mountain Fault, ~10,000 cal year B.P. (Reheis, 1996; DePolo, 1989). Given that movement on the Owens Valley fault in 1872 caused a number of rock falls in Yosemite and the coincidence of ages between the Tiltill 'slide' and paleoseismic events, a large earthquake in Eastern Sierra Nevada may have triggered this event. Other trigger events are also possibilities, but only through compilation of a database of large rock avalanches can statistically significant groupings of events begin to demonstrate whether seismic triggering is a dominant process.

  15. The light curve of SN 1987A revisited: constraining production masses of radioactive nuclides

    SciTech Connect

    Seitenzahl, Ivo R.; Timmes, F. X.; Magkotsios, Georgios

    2014-09-01

    We revisit the evidence for the contribution of the long-lived radioactive nuclides {sup 44}Ti, {sup 55}Fe, {sup 56}Co, {sup 57}Co, and {sup 60}Co to the UVOIR light curve of SN 1987A. We show that the V-band luminosity constitutes a roughly constant fraction of the bolometric luminosity between 900 and 1900 days, and we obtain an approximate bolometric light curve out to 4334 days by scaling the late time V-band data by a constant factor where no bolometric light curve data is available. Considering the five most relevant decay chains starting at {sup 44}Ti, {sup 55}Co, {sup 56}Ni, {sup 57}Ni, and {sup 60}Co, we perform a least squares fit to the constructed composite bolometric light curve. For the nickel isotopes, we obtain best fit values of M({sup 56}Ni) = (7.1 ± 0.3) × 10{sup –2} M {sub ☉} and M({sup 57}Ni) = (4.1 ± 1.8) × 10{sup –3} M {sub ☉}. Our best fit {sup 44}Ti mass is M({sup 44}Ti) = (0.55 ± 0.17) × 10{sup –4} M {sub ☉}, which is in disagreement with the much higher (3.1 ± 0.8) × 10{sup –4} M {sub ☉} recently derived from INTEGRAL observations. The associated uncertainties far exceed the best fit values for {sup 55}Co and {sup 60}Co and, as a result, we only give upper limits on the production masses of M({sup 55}Co) < 7.2 × 10{sup –3} M {sub ☉} and M({sup 60}Co) < 1.7 × 10{sup –4} M {sub ☉}. Furthermore, we find that the leptonic channels in the decay of {sup 57}Co (internal conversion and Auger electrons) are a significant contribution and constitute up to 15.5% of the total luminosity. Consideration of the kinetic energy of these electrons is essential in lowering our best fit nickel isotope production ratio to [{sup 57}Ni/{sup 56}Ni] = 2.5 ± 1.1, which is still somewhat high but is in agreement with gamma-ray observations and model predictions.

  16. [Bibliographic consideration of proper management of radioactive waste on short-lived period nuclides that are used in nuclear medicine].

    PubMed

    Kida, Tetsuo; Watanabe, Hiroshi; Yamaguchi, Ichirou; Nagaoka, Hiroaki; Fujibuchi, Toshioh; Tanaka, Shinji; Hayakawa, Toshio

    2009-05-20

    A rational clearance system for medical radioactive waste has not yet been established in Japan. As Europe and USA's ways, the establishment of DIS that medical radioactive waste what are kept in storage room for more than decided period each nuclide except from regulation of radiation's control. The purpose of this report is to clarify the problems with the establishment of DIS in Japan through a literature review of the experience in Europe and the USA and previous research that has been reported in Japan. To establish the DIS system, the radiation control system in nuclear medicine should be rebuilt and put into effect.

  17. Nuclear medical imaging using β+γ coincidences from 44Sc radio-nuclide with liquid xenon as detection medium

    NASA Astrophysics Data System (ADS)

    Grignon, C.; Barbet, J.; Bardiès, M.; Carlier, T.; Chatal, J. F.; Couturier, O.; Cussonneau, J. P.; Faivre, A.; Ferrer, L.; Girault, S.; Haruyama, T.; Le Ray, P.; Luquin, L.; Lupone, S.; Métivier, V.; Morteau, E.; Servagent, N.; Thers, D.

    2007-02-01

    We report on a new nuclear medical imaging technique based on the measurement of the emitter location in the three dimensions with a few mm spatial resolution using β+γ emitters. Such measurement could be realized thanks to a new kind of radio-nuclides which emit a γ-ray quasi-simultaneously with the β+ decay. The most interesting radio-nuclide candidate, namely 44Sc, will be potentially produced at the Nantes cyclotron ARRONAX. The principle is to reconstruct the intersection of the classical line of response (obtained with a standard PET camera) with the direction cone defined by the third γ-ray. The emission angle measurement of this additional γ-ray involves the use of a Compton telescope for which a new generation of camera based on a liquid xenon (LXe) time projection chamber is considered. GEANT3 simulations of a large acceptance LXe Compton telescope combined with a commercial micro-PET (LSO crystals) have been performed and the obtained results will be presented. They demonstrate that a good image can be obtained from the accumulation of each three-dimensional measured position. A spatial resolution of 2.3 mm has been reached with an injected activity of 0.5 MBq for a 44Sc point source emitter.

  18. Comparative study of beta-decay data for eight nuclides measured at the Physikalisch-Technische Bundesanstalt

    NASA Astrophysics Data System (ADS)

    Sturrock, P. A.; Fischbach, E.; Javorsek, D.; Jenkins, J. H.; Lee, R. H.; Nistor, J.; Scargle, J. D.

    2014-07-01

    We present the results of time-series analyses of data, kindly provided by the Physikalisch-Technische Bundesanstalt, concerning the beta-decays of Ag108, Ba133, Cs137, Eu152, Eu154, Kr85, Ra226, and Sr90. From measurements of the detector currents, we find evidence of annual oscillations (especially for Ra226), and for several solar r-mode oscillations. It is notable that the frequencies of these r-mode oscillations correspond to exactly the same sidereal rotation rate (12.08 year-1) that we have previously identified in r-mode oscillations detected in both Mt Wilson solar diameter data and Lomonosov Moscow State University Sr90 beta-decay data. Ba133 is found to be anomalous in that current measurements for this nuclide have a much larger variation (by 4 σ) than those of the other nuclides. It is interesting that analysis of variability measurements in the PTB files yields strong evidence for an oscillation for Ba133 but only weak evidence for Ra226.

  19. Sequential multi-nuclide emission rate estimation method based on gamma dose rate measurement for nuclear emergency management.

    PubMed

    Zhang, Xiaole; Raskob, Wolfgang; Landman, Claudia; Trybushnyi, Dmytro; Li, Yu

    2017-03-05

    In case of a nuclear accident, the source term is typically not known but extremely important for the assessment of the consequences to the affected population. Therefore the assessment of the potential source term is of uppermost importance for emergency response. A fully sequential method, derived from a regularized weighted least square problem, is proposed to reconstruct the emission and composition of a multiple-nuclide release using gamma dose rate measurement. The a priori nuclide ratios are incorporated into the background error covariance (BEC) matrix, which is dynamically augmented and sequentially updated. The negative estimations in the mathematical algorithm are suppressed by utilizing artificial zero-observations (with large uncertainties) to simultaneously update the state vector and BEC. The method is evaluated by twin experiments based on the JRodos system. The results indicate that the new method successfully reconstructs the emission and its uncertainties. Accurate a priori ratio accelerates the analysis process, which obtains satisfactory results with only limited number of measurements, otherwise it needs more measurements to generate reasonable estimations. The suppression of negative estimation effectively improves the performance, especially for the situation with poor a priori information, where it is more prone to the generation of negative values. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Spatial and temporal variations in denudation rates derived from cosmogenic nuclides in four European fluvial terrace sequences

    NASA Astrophysics Data System (ADS)

    Schaller, M.; Ehlers, T. A.; Stor, T.; Torrent, J.; Lobato, L.; Christl, M.; Vockenhuber, C.

    2016-12-01

    The denudation of landscapes is affected by temporal and spatial variations in tectonics, climate, and vegetation. However, deciphering the contributions of these different processes has proven challenging. In this study, cosmogenic nuclide-derived modern and paleo catchment-wide denudation rates in four European rivers are investigated. We present 12 new and 4 recalculated cosmogenic nuclide-derived denudation rates from modern river sediments and 14 paleo-denudation rates from terraces deposited over the last 2 Ma. The catchments studied are located in regions with minimal Quaternary tectonic activity and span different climates over 12o latitude. Results indicate that modern denudation rates range between 16 ± 11 and 51 ± 7 mm/ka with no clear latitudinal variation. Modern denudation rates are compared with catchment geomorphic indices including slope, fluvial steepness index, and relief. The denudation rates correlate better to catchment topographic indices (R2 ≈ 0.4) rather than climate. Paleo-denudation rates range from 8 ± 7 to 56 ± 7 mm/ka and are associated with a possible increase in the average paleo-denudation rates over the past 2 Ma. Taken together, the results indicate that quantification of catchment-wide denudation rates over long (Quaternary) time scales because of climate change is difficult. Future work to study climate influence on denudation rates should focus on the successes of previous work that document transient denudation rates over shorter and more recent time scales, i.e., from the Last Glacial Maximum to present.

  1. Mid-Pleistocene cosmogenic minimum-age limits for pre-Wisconsinan glacial surfaces in southwestern Minnesota and southern Baffin Island: A multiple nuclide approach

    USGS Publications Warehouse

    Bierman, P.R.; Marsella, K.A.; Patterson, Chris; Davis, P.T.; Caffee, M.

    1999-01-01

    Paired 10Be and 26Al analyses (n = 14) indicate that pre-Wisconsinan, glaciated bedrock surfaces near the northern (Baffin Island) and southern (Minnesota) paleo-margins of the Laurentide Ice Sheet have long and complex histories of cosmic-ray exposure, including significant periods of partial or complete shielding from cosmic rays. Using the ratio, 26Al/10Be, we calculate that striated outcrops of Sioux Quartzite in southwestern Minnesota (southern margin) were last overrun by ice at least 500,000 years ago. Weathered bedrock tors on the once-glaciated uplands of Baffin Island (northern margin) are eroding no faster than 1.1 m Myr-1, the equivalent of at least 450,000 years of surface and near-surface exposure. Our data demonstrate that exposure ages and erosion rates calculated from single nuclides can underestimate surface stability dramatically because any intermittent burial, and the resultant lowering of nuclide production rates and nuclide abundances, will remain undetected.

  2. Mass Measurements of Proton-rich Nuclides at the Cooler Storage Ring at IMP

    SciTech Connect

    Zhang, Y. H.; Xu, H. S.; Wang, M.; Zhou, X. H.; Yuan, Y. J.; Xia, J. W.; Hu, Z. G.; Huang, W. X.; Liu, Y.; Ma, X.; Mao, R. S.; Mei, B.; Sun, Z. Y.; Wang, J. S.; Xiao, G. Q.; Yan, X. L.; Yang, J. C.; Zhao, H. W.; Zhao, T. C.; Zhang, X. Y.; and others

    2011-11-30

    Recent results and progress of mass measurements of proton-rich nuclei using isochronous mass spectrometry (IMS) are reported. The nuclei under investigation were produced via fragmentation of relativistic energy heavy ions of {sup 78}Kr and {sup 58}Ni. After in-flight separation by the fragment separator RIBLL-2, the nuclei were injected and stored in the experimental storage ring CSRe, and their masses were determined from measurements of the revolution times. The impact of these measurements on the stellar nucleosynthesis in the rp-process is discussed.

  3. Natural Paleoseismometers: Cosmogenic Nuclide Dating of Precariously Balanced Rocks (PBRs) - Integral Constraints on Maximum Ground Accelerations

    NASA Astrophysics Data System (ADS)

    Perg, L. A.; Ludwig, L. G.; Kendrick, K.; Brune, J.; Purvance, M.; Anooshehpoor, R.; Akciz, S.

    2007-12-01

    Precariously balanced rocks (PBRs) act as natural seismometers constraining maximum ground acceleration over the surface exposure history of the PBR. These key paleoseismic indicators have the potential to validate ground motions on the timescale necessary to test earthquake rupture forecasts and Seismic Hazard Assessment estimates, and are an active topic of research to validate CyberShake results and constrain National Seismic Hazard Maps. This research focuses on examining the post-exhumation history of PBRs using in-situ terrestrial cosmogenic nuclides (TCNs). TCNs provide a record of near-surface exposure history. The measured concentrations are a function of the residence time in the upper ~20 m of the subsurface (inherited concentration), the timing and rate of exhumation, and post-exhumation surface spalling and chemical erosion. Our goal in the project is to provide reasonable constraints on the post-exhumation history, specifically the age of the PBRs and evolution of precariousness: we should be able to constrain whether the rocks were of similar precariousness 2.5 ka, 5 ka, and 10 ka ago. These specific targets will provide important constraints on time since exceedance for the CyberShake models. We developed our sampling strategy to address subsurface inheritance, exhumation rate and timing, and post- exhumation spalling and chemical erosion. PBRs were selected to meet a variety of considerations. These rocks constrain ground motions from large earthquakes on the San Jacinto and Elsinore faults, in Southern California. Inherited concentrations lead to an age estimate that is too old; we are investigating inherited concentrations though sampling a rock quarry near Perris CA, with shielded samples at greater than 15 m depth. We also have partially shielded samples from the interior of rocks toppled to measure their stability, and through vandalism. To determine exhumation age and rate, our sampling strategy is to collect 5-6 samples per PBR: 1 on top, 3

  4. Using cosmogenic nuclides to date the stabilisation age of relict rockglaciers

    NASA Astrophysics Data System (ADS)

    Kronig, Olivia; Reitner, Jürgen M.; Christl, Marcus; Ivy-Ochs, Susan

    2017-04-01

    Active rockglaciers are periglacial landforms which are creeping down mountain slopes due to plastic deformation of the interstitial ice. The occurrence of active rockglaciers is an indicator of Alpine permafrost. Relict rockglaciers are not moving anymore because the ice melted, but they give evidence for the earlier existence of permafrost. In the Alps, relict rockglaciers can often be found below today's tree line raising the question of when these landforms have last been active. Judging from the present position of the relict rockglaciers, the lower permafrost limit during the time of their activity must have been hundreds of meters lower than it is today. Already in the early days of rockglacier research, the potential of relict rockglaciers as a paleoclimate proxy was recognised (Barsch 1977, Haeberli 1985). However, obtaining absolute ages on relict rockglaciers has always been a major difficulty. Lately it has been shown that with cosmogenic nuclides it is possible to date the stabilisation age of relict rockglaciers, but it has been applied only in a few cases (Ivy-Ochs et al. 2009). According to Reitner (2007), the lowest relict rockglaciers of the eastern Alps, the Tandl rockglaciers, are located in the Province of Carinthia (Austria). The Tandl rockglaciers are a complex series of rockglaciers spanning from around 2300 m down to 1220 m a.s.l. Due to their low position and based on modelling estimates on permafrost distribution in the area (Avian & Kellerer-Pirklbauer 2012), it is plausible that these low rockglaciers were active even prior to the Younger Dryas. Therefore, samples from the entire rockglacier series were taken for 10Be exposure dating. Furthermore, the close proximity of the rockglaciers to moraines associated to the Gschnitz stadial allow comparing the dating results to equilibrium line depression reconstructions. Less than 10 km to the southwest, a second rockglacier series, the Norbert rockglaciers, was sampled. In contrast to the

  5. Terrestrial Cosmogenic-Nuclide Dating of Alluvial Fans in Death Valley, California

    USGS Publications Warehouse

    Machette, Michael N.; Slate, Janet L.; Phillips, Fred M.

    2008-01-01

    We have used terrestrial cosmogenic nuclides (TCN) to establish the age of some of the most extensive Quaternary alluvial fans in Death Valley, California. These intermediate-age alluvial fans are most extensive on the western side of the valley, where tectonic deformation is considerably less pronounced than on the eastern side of the valley. These fans are characterized by a relatively smooth, densely packed desert pavement formed by well-varnished (blackened) clasts. These surfaces have been mapped as the Q2 gravel by previous workers and as unit Qai (intermediate age) by us. However, the intermediate-age gravels probably contain multiple subunits, as evidenced by slight differences in morphologic expression, soil formation, and inset geomorphic relations. The TCN technique used herein sums the cosmogenic 36Cl in approximately 2.5-meter-deep profiles through soil and host alluvium, thus avoiding some of the problems associated with the more typical surface-exposure dating of boulders or smaller clasts. Our TCN 36Cl dating of 12 depth profiles indicates that these intermediate-age (Qai) alluvial fans range from about 100 to 40 kilo-annum (ka), with a mean age of about 70 ka. An alternative interpretation is that alluvial unit Qai was deposited in two discrete episodes from 90 to 80 ka and from 60 to 50 ka, before and after MIS (marine oxygen-isotope stage) 4 (respectively). Without an intermediate-age unit, such as MIS 4 lake deposits, we can neither disprove nor prove that Qai was deposited in two discrete intervals or over a longer range of time. Thus, in Death Valley, alluvial unit Qai largely brackets MIS 4, which is not associated with a deep phase of Lake Manly. These Qai fans extend to elevations of about -46 meters (150 feet below sea level) and have not been transgressed by Lake Manly, suggesting that MIS 4 or MIS 2 lakes were rather shallow in Death Valley, perhaps because they lacked inflow from surface runoff of the Sierra Nevada drainages through

  6. Potential resolution of discrepancies between scaling models for in situ cosmogenic nuclide production rates

    NASA Astrophysics Data System (ADS)

    Lifton, N. A.

    2010-12-01

    Two main types of theoretical models are used currently for scaling in situ cosmogenic nuclide (CN) production rates in time and space, distinguished primarily by the data on which they are based. The first of these, that of Lal (1991, EPSL 104, p. 424, reparameterized by Stone, 2000, JGR 105, p. 23,753), is based on atmospheric measurements of nuclear disintegrations in photographic emulsions combined with data from various neutron detectors sensitive to different portions of the secondary cosmic-ray spectrum. The other published models for scaling CN production rates (Dunai, 2001, EPSL 193, p 197; Lifton et al. 2005, EPSL 239, p. 140; Desilets and Zreda, 2006, EPSL 206, p 21) are based (either largely or entirely) on data from neutron monitors, which all sample similar portions of the cosmic-ray spectrum. A further distinction is that the neutron monitor-based models accommodate a time-dependent geomagnetic field, while the Lal model does not. While both model types yield similar predictions for sites in middle to high latitudes and low to middle altitudes (<2 km), predictions diverge at low latitudes and high altitudes. This discrepancy arises primarily from the different altitude dependences of each data source - neutron monitor-based models predict a faster increase in cosmic ray intensity with altitude than does the Lal model. Unfortunately, previously published production rate calibration data (e.g., Balco et al., 2008, Quat. Geochron. 3, p. 174) were neither sufficiently consistent among sites nor adequately precise to identify which of these models was correct. The CRONUS-Earth Project, which aims to better characterize production rate systematics for all commonly measured CNs, has been working to resolve this discrepancy. A potential solution may be found in the atmospheric cosmic ray flux models of Sato and Niita (2006, Radiation Res. 166, p. 544) and Sato et al. (2008, Radiation Res. 170, p. 244), combined with new, high-precision in situ cosmogenic 10

  7. Cosmogenic nuclide concentrations in Neogene rivers of the Great Plains reveal the evolution of fluvial storage and recycling

    NASA Astrophysics Data System (ADS)

    Sinclair, Hugh; Stuart, Fin; McCann, Louise; Tao, Zui

    2016-04-01

    The measurement of the duration of near surface residence of sediment grains from the stratigraphic record has the potential to quantitatively reconstruct processes such as stratal condensation, sediment recycling and the exposure histories of unconformities. Geomorphological measurements of dates and rates of surfaces and erosion respectively has enabled significant advances in understanding, however, the radiogenic half life of typical cosmogenic nuclides such as 10Be and 26Al means they are not suitable for the stratigraphic record. Instead, we have applied the stable cosmogenic nuclide of 21Ne to quartz-rich sediment to quantify the routing history of the river systems that have drained the southern Rockies of Wyoming and Colorado during Neogene times. The Neogene sediments of Nebraska record fluvial systems of the Great Plains that flow from the Rockies towards the east and into the Mississippi catchment. This succession is <300 m thick, and records successive episodes of fluvial incision and aggradation associated with regional tilting from 6 to 4 Ma and periods of climate change. As part of an evaluation of the application of 21Ne to the stratigraphic record, we sampled quartzite pebbles from an Upper Miocene, Pliocene and modern river channel of the North Platte approximately 400 km from their mountainous source. The quartzite is derived from a single exposure of the Medicine Bow quartzites in Wyoming, therefore all three intervals recorded the same travel distance from source. Additionally, we know the erosion rate of the Medicine Bow quartzites from detrital 10Be analyses, and we also sampled shielded bedrock samples from the quartzite to evaluate for any non-cosmogenic 21Ne. This means that the concentrations of 21Ne in detrital pebbles >400 km from their source could be corrected for both inherited non-cosmogenic and erosion induced accumulation at source. Therefore, any additional amounts of 21Ne must record storage and exposure during transport down

  8. Actinide production in the reaction of heavy ions with curium-248

    SciTech Connect

    Moody, K.J.

    1983-01-01

    Chemical experiments were performed to examine the usefulness of heavy ion transfer reactions in producing new, neutron-rich actinide nuclides. A general quasi-elastic to deep-inelastic mechanism is proposed, and the utility of this method as opposed to other methods (e.g. complete fusion) is discussed. The relative merits of various techniques of actinide target synthesis are discussed. A description is given of a target system designed to remove the large amounts of heat generated by the passage of a heavy ion beam through matter, thereby maximizing the beam intensity which can be safely used in an experiment. Also described is a general separation scheme for the actinide elements from protactinium (Z = 91) to mendelevium (Z = 101), and fast specific procedures for plutonium, americium and berkelium. The cross sections for the production of several nuclides from the bombardment of /sup 248/Cm with /sup 18/Kr and /sup 86/O, /sup 136/Xe projectiles at several energies near and below the Coulomb barrier were determined. The results are compared with yields from /sup 48/Ca and /sup 238/U bombardments of /sup 248/Cm. A preliminary, unsuccessful attempt to isolate /sup 247/Pu is outlined. The absolute ..gamma.. ray intensities from /sup 251/Bk decay, necessary for calculating the /sup 251/Bk cross section, are also determined.

  9. 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.

  10. Chlorine-36 in fossil rat urine: An archive of cosmogenic nuclide deposition during the past 40,000 years

    SciTech Connect

    Plummer, M.A.; Phillips, F.M.; Fabryka-Martin, J.

    1997-07-25

    Knowledge of the production history of cosmogenic nuclides, which is needed for geological and archaeological dating, has been uncertain. Measurements of chlorine-36/chlorine ({sup 36}Cl/Cl) ratios in fossil packrat middens from Nevada that are radiocarbon-dated between about 38 thousand years ago (ka) and the present showed that {sup 36}Cl/Cl ratios were higher by a factor of about 2 before {approx} 11 ka. This raises the possibility that cosmogenic production rates just before the close of the Pleistocene were up to 50% higher than is suggested by carbon-14 calibration data. The discrepancy could be explained by addition of low-carbon-14 carbon dioxide to the atmosphere during that period, which would have depressed atmospheric radiocarbon activity. Alternatively, climatic effects on {sup 36}Cl deposition may have enhanced the {sup 36}Cl/Cl ratios. 49 refs., 3 figs.

  11. A Physical Model of Cosmogenic Nuclide Production in Stony and Iron Meteoroids on the Basis of Simulation Experiments

    NASA Astrophysics Data System (ADS)

    Leya, I.; Lange, H.-J.; Michel, R.; Meltzow, B.; Herpers, U.; Busemann, H.; Wieler, R.; Dittrich-Hannen, B.; Suter, M.; Kubik, P. W.

    1995-09-01

    By extending and improving earlier model calculations [1-4] of cosmogenic nuclide production by GCR particles in extraterrestrial matter, we can now present a physical model without free parameters for a consistent description of GCR production rates in stony and iron meteoroids. The model takes explicitely into account p and n-induced reactions. GCR 4He particles are considered only approximately. It is based on depth-size and bulk-chemistry-dependent spectra of primary and secondary protons and of secondary neutrons calculated by HET and MORSE codes within the HERMES code system [5] and on the cross sections of the underlying reactions. Comprehensive and reliable sets of proton cross sections from thresholds up to 2.6 GeV exist now for many cosmogenic nuclides (see [6] for a review). For n-induced reactions the situation is not so good. Only a few data at low energies and practically no data at higher energies exist. GCR production of cosmogenic nuclides in stony meteoroids is already dominated by neutron-induced reactions for most meteoroid radii. In iron meteoroids neutrons are even more important because of the high mass numbers of the bulk and of consequently higher multiplicities for production of secondary neutrons. In order to overcome this problem, the necessary excitation functions of neutron-induced reactions were determined from experimental thick-target production rates by least-squares unfolding procedures using the code STAYS'L [7]. The data were produced in laboratory experiments under completely controlled conditions [8-11]. The unfolding procedure starts from guess functions (from threshold up to 900 MeV) based on all available experimental neutron cross sections and on theoretical ones calculated by the AREL [12] code which is a relativistic version of the hybrid model of pre-equilibrium reactions [13]. With the new neutron cross sections it is possible to describe simultanously all data from the simulation experiments with an accuracy of better

  12. Toward using millennial-scale geomagnetic field models to constrain in situ cosmogenic nuclide production rate variations

    NASA Astrophysics Data System (ADS)

    Lifton, N. A.

    2005-12-01

    The geomagnetic field exerts a strong influence on the trajectories of charged primary cosmic-ray particles incident on the Earth's atmosphere (and therefore, on the geographic distribution of their progeny). The resulting cascade of secondary particles then interacts with the top few meters of the Earth's surface to produce various nuclides in situ (in situ cosmogenic nuclides, or CNs). With appropriate interpretive models, concentrations of these nuclides measured in terrestrial materials can be used to infer the duration of surface exposure (or of burial following exposure) and rates of various surficial processes. However, the potential precision with which CNs can be applied is limited by how well their production rates are known. Nuclide production rates are typically determined by measuring CN concentrations in surficial rocks with well-constrained exposure histories. Scaling these time-integrated production rates to other locations with different exposure durations, though, requires knowledge or assumptions of how instantaneous production rates have varied in space and time. Spatial scaling of CN production rates is typically described by models based on modern secondary cosmic-ray measurements, ordered by parameters linked to the geomagnetic field. In general, the most robust parameter for ordering these measurements is the effective vertical cutoff rigidity (RC), a measure of the energy required for primary cosmic rays to penetrate the geomagnetic and magnetospheric fields and interact with the atmosphere at a given location. Temporal variations in CN production rates at a given site result primarily from changes in the orientation and intensity of the geomagnetic field. These geomagnetic variations have been modeled for CN applications using estimates of Holocene variations in dipole orientation combined with records of global dipole intensity variations. It has typically been assumed in CN research that secular variation of the geomagnetic pole averages

  13. 26Al - 10Be cosmogenic nuclide isochron burial dating in combination with luminescence dating of two Danube terraces

    NASA Astrophysics Data System (ADS)

    Neuhuber, Stephanie; Braumann, Sandra; Lüthgens, Christopher; Fiebig, Markus; Häuselmann, Philipp; Schäfer, Jörg

    2016-04-01

    The Quaternary sediment record in the Vienna Basin is influenced by two main factors: (1) the tectonic development of a pull apart basin along a sinistral strike slip fault system between the Eastern Alps and the West Carpathians and by (2) strongly varying sediment supply during the Plio- and Pleistocene. From the Late Pannonian (8.8 Ma) onward a large-scale regional uplift (Decker et al., 2005) controls terrace formation in the Vienna Basin. The main sediment supply into the Vienna Basin originates from the Danube, and subordinately from tributaries to the south such as Piesting, Fischa, Leitha and from the north by the river March. Today the Danube forms a large floodplain that is bordered to the north by one large Pleistocene terrace, the Gänserndorf Terrace that is situated 17 m above todays water level. Farther to the east a smaller terrace, the Schlosshof Terrace, reaches 25 m above todays water level. These terrace levels are tilted by movement of underlying blocks (Peresson, 2006). Both, the Schlosshof and Gänserndorf terraces consist of successions of up to 2 m thick gravel beds with intercalated sand layers or -lenses that may locally reach thicknesses up to 0.8 m. At each terrace one gavel pit was selected to calculate the time of terrace deposition by luminescence dating in combination with 26Al/10Be cosmogenic nuclide isochrone dating (Balco and Rovery, 2008). Five quartz stones from the base of each terrace were physically and chemically processed to obtain Al and Be oxides for Acceleration Mass Spectrometry. Sand samples for luminescence dating were taken above the cosmogenic nuclide samples from the closest suitable sand body. Decker et al., 2005. QSR 24, 307-322 Peresson, 2006 Geologie der österreichischen Bundesländer Niederösterreich 255-258 Balco and Rovey, 2008. AJS 908, 1083-1114 Thanks to FWF P 23138-N19, OMAA 90öu17

  14. Fate of nuclides in natural-water systems. Annual progress report, October 1, 1981-March 31, 1983

    SciTech Connect

    Turekian, K.K.

    1982-11-30

    The atmospheric fluxes of /sup 210/Pb and /sup 7/Be at New Haven, CT, and Bermuda were determined and compared with model fluxes. The reliability of these radionuclides as tracers for other chemical species injected into the atmosphere by human activity was therefore tested. The distribution of /sup 10/Be in soil profiles was studied. The initial aim was to use the standing crop of /sup 10/Be in the soil to obtain an exposure age of the surface. Dated surfaces (i.e. raised coastal terraces, dated volcanic flows, etc) showed that /sup 10/Be does not totally accumulate in the soils but is mobilized. The mean residence time appears to be about 20,000 years. In a related study a number of the members of the /sup 238/U and /sup 232/Th decay series nuclides were measured in the major ground water aquifer types in Connecticut. Using /sup 222/Rn as a flux indicator it was possible to determine the adsorption and desorption coefficients, distribution coefficients and retardation factors of Ra, Pb, and Th in these aquifers. The study of the transport of nuclides by the Connecticut River and the study of the Amazon River plume were completed. Also completed was one of the most intensive studies of the behavior of natural radionuclides and plutonium in an estuarine system, the Long Island Sound, by analyzing two nearshore sites (SACHEM and FOAM) to complement the deep water sites (NWC and DEEP). The chronologies of accumulation, bioturbation, human disturbance and physical change were established for these varied environments.

  15. Gaussian Modification of Neutrino Energy Losses in Electron Capture Processes of Nuclides 56Fe, 56Co, 56Ni and 56Mn in Stellar Interiors

    NASA Astrophysics Data System (ADS)

    Liu, Jing-jing; Luo, Zhi-quan

    2010-10-01

    By using the Gaussian modification method, the neutrino energy losses in the electron capture processes of nuclides 56Fe, 56Co, 56Ni and 56Mn are investigated. The results show that the energy loss rate of neutrinos is increased due to the Gaussian modification of the energy level distribution of the Gamow-Teller (GT) resonance transitions of nuclides. In the reactions dominated by the electron capture processes of the low-energy transitions, the Gaussian modification has a very small influence on the neutrino energy losses. When the high-energy G-T resonance transition is the main electron capture process, the influence on the neutrino energy losses will be greatly increased. For example, the correctional differences of nuclide 56Fe are about 2 orders of magnitude when the density ρ7 = 100 (ρ7 is in units of 10 7 mol × cm -3) and the half width of Gaussian function Δ = 14.3, 18.3, 22.3 Mev, and those of nuclide 56Ni are about 60% and 40% when Δ = 6.3, 18.3 Mev, respectively.

  16. Detailed deposition density maps constructed by large-scale soil sampling for gamma-ray emitting radioactive nuclides from the Fukushima Dai-ichi Nuclear Power Plant accident.

    PubMed

    Saito, Kimiaki; Tanihata, Isao; Fujiwara, Mamoru; Saito, Takashi; Shimoura, Susumu; Otsuka, Takaharu; Onda, Yuichi; Hoshi, Masaharu; Ikeuchi, Yoshihiro; Takahashi, Fumiaki; Kinouchi, Nobuyuki; Saegusa, Jun; Seki, Akiyuki; Takemiya, Hiroshi; Shibata, Tokushi

    2015-01-01

    Soil deposition density maps of gamma-ray emitting radioactive nuclides from the Fukushima Dai-ichi Nuclear Power Plant (NPP) accident were constructed on the basis of results from large-scale soil sampling. In total 10,915 soil samples were collected at 2168 locations. Gamma rays emitted from the samples were measured by Ge detectors and analyzed using a reliable unified method. The determined radioactivity was corrected to that of June 14, 2011 by considering the intrinsic decay constant of each nuclide. Finally the deposition maps were created for (134)Cs, (137)Cs, (131)I, (129m)Te and (110m)Ag. The radioactivity ratio of (134)Cs-(137)Cs was almost constant at 0.91 regardless of the locations of soil sampling. The radioactivity ratios of (131)I and (129m)Te-(137)Cs were relatively high in the regions south of the Fukushima NPP site. Effective doses for 50 y after the accident were evaluated for external and inhalation exposures due to the observed radioactive nuclides. The radiation doses from radioactive cesium were found to be much higher than those from the other radioactive nuclides. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  17. Actinide Production in the Reaction of Heavy Ions withCurium-248

    SciTech Connect

    Moody, K.J.

    1983-07-01

    Chemical experiments were performed to examine the usefulness of heavy ion transfer reactions in producing new, neutron-rich actinide nuclides. A general quasi-elastic to deep-inelastic mechanism is proposed, and the utility of this method as opposed to other methods (e.g. complete fusion) is discussed. The relative merits of various techniques of actinide target synthesis are discussed. A description is given of a target system designed to remove the large amounts of heat generated by the passage of a heavy ion beam through matter, thereby maximizing the beam intensity which can be safely used in an experiment. Also described is a general separation scheme for the actinide elements from protactinium (Z = 91) to mendelevium (Z = 101), and fast specific procedures for plutonium, americium and berkelium. The cross sections for the production of several nuclides from the bombardment of {sup 248}Cm with {sup 18}O, {sup 86}Kr and {sup 136}Xe projectiles at several energies near and below the Coulomb barrier were determined. The results are compared with yields from {sup 48}Ca and {sup 238}U bombardments of {sup 248}Cm. Simple extrapolation of the product yields into unknown regions of charge and mass indicates that the use of heavy ion transfer reactions to produce new, neutron-rich above-target species is limited. The substantial production of neutron-rich below-target species, however, indicates that with very heavy ions like {sup 136}Xe and {sup 238}U the new species {sup 248}Am, {sup 249}Am and {sup 247}Pu should be produced with large cross sections from a {sup 248}Cm target. A preliminary, unsuccessful attempt to isolate {sup 247}Pu is outlined. The failure is probably due to the half life of the decay, which is calculated to be less than 3 minutes. The absolute gamma ray intensities from {sup 251}Bk decay, necessary for calculating the {sup 251}Bk cross section, are also determined.

  18. A Multi-nuclide Approach to the Exposure Timing of Alpine Summits in Northwestern Svalbard: Results from in-situ 14C Measurements in Quartz

    NASA Astrophysics Data System (ADS)

    Lamp, J. L.; Schaefer, J. M.; Koffman, T. N. B.; Briner, J. P.; Gjermundsen, E. F.; Young, N. E.; Hormes, A.

    2016-12-01

    Deglaciation histories of the Polar Regions provide important insights into ice-sheet and climate dynamics, but cosmogenic nuclide surface exposure studies from these cold and arid regions based on stable (3He and 21Ne) or long-lived (10Be and 26Al) isotopes are frequently hampered by the problem of cosmogenic nuclide inheritance from prior exposure periods. In-situ 14C can add complementary information in such cases, as its half-life is only 5730 years. 14C is essentially reset during periods of significant glaciation lasting longer than 20,000 years, and therefore does not suffer from the same inheritance complication of longer lived nuclides. Additionally, 14C is produced and retained in the ubiquitous mineral quartz, making it applicable in most terrestrial settings, and, when coupled with 10Be and 26Al measurements, can provide a better understanding of landscape evolution during the Holocene and late Pleistocene. Here we present a multi-nuclide approach to the timing and duration of exposure of steep alpine summits in Northwestern Spitsbergen, including a new 14C dataset from quartz. It remains unclear whether Svalbard was overwhelmed by the marine-based Barents-Kara Ice Sheet during the Last Glacial Maximum, or if there were ice-free nunataks. Our 14C results show that peaks in the Northwest region of Svalbard have remained ice-free or under only a thin ice cover, since at least the late Pleistocene. The data strengthen the conclusions of 10Be/26Al nuclide studies which imply that these peaks exhibit extremely low erosion rates in comparison to other steep, glaciated, alpine landscapes during the Quaternary, and support the use of 14C as a method to better elucidate the recent glacial history and surface processes in polar locales.

  19. Miocene to recent ice elevation variations from the interior of the West Antarctic ice sheet: Constraints from geologic observations, cosmogenic nuclides and ice sheet modeling

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, Sujoy; Ackert, Robert P.; Pope, Allen E.; Pollard, David; DeConto, Robert M.

    2012-07-01

    Observations of long-term West Antarctic Ice Sheet (WAIS) behavior can be used to test and constrain dynamic ice sheet models. Long-term observational constraints are however, rare. Here we present the first constraints on long-term (Miocene-Holocene) WAIS elevation from the interior of the ice sheet near the WAIS divide. We use geologic observations and measurements of cosmogenic 21Ne and 10Be in bedrock surfaces to constrain WAIS elevation variations to <160 m above the present-day ice levels since 7 Ma, and <110 m above present-day ice levels since 5.4 Ma. The cosmogenic nuclide data indicate that bedrock surfaces 35 m above the present-day ice levels had near continuous exposure over the past 3.5 Ma, requiring average interior WAIS elevations to have been similar to, or lower than present, since the beginning of the Pliocene warm period. We use a continental ice sheet model to simulate the history of ice cover at our sampling sites and thereby compute the expected concentration of the cosmogenic nuclides. The ice sheet model indicates that during the past 5 Ma interior WAIS elevations of >65 m above present-day ice levels at the Ohio Range occur only rarely during brief ice sheet highstands, consistent with the observed cosmogenic nuclide data. Furthermore, the model's prediction that highstand elevations have increased on average since the Pliocene is in good agreement with the cosmogenic nuclide data that indicate the highest ice elevation over the past 5 Ma was reached during the highstand at 11 ka. Since the simulated cosmogenic nuclide concentrations derived from the model's ice elevation history are in good agreement with our measurements, we suggest that the model's prediction of more frequent collapsed-WAIS states and smaller WAIS volumes during the Pliocene are also correct.

  20. Heavy quark masses

    NASA Technical Reports Server (NTRS)

    Testa, Massimo

    1990-01-01

    In the large quark mass limit, an argument which identifies the mass of the heavy-light pseudoscalar or scalar bound state with the renormalized mass of the heavy quark is given. The following equation is discussed: m(sub Q) = m(sub B), where m(sub Q) and m(sub B) are respectively the mass of the heavy quark and the mass of the pseudoscalar bound state.

  1. Production of heavy water

    DOEpatents

    Spencer, Larry S.; Brown, Sam W.; Phillips, Michael R.

    2017-06-06

    Disclosed are methods and apparatuses for producing heavy water. In one embodiment, a catalyst is treated with high purity air or a mixture of gaseous nitrogen and oxygen with gaseous deuterium all together flowing over the catalyst to produce the heavy water. In an alternate embodiment, the deuterium is combusted to form the heavy water. In an alternate embodiment, gaseous deuterium and gaseous oxygen is flowed into a fuel cell to produce the heavy water. In various embodiments, the deuterium may be produced by a thermal decomposition and distillation process that involves heating solid lithium deuteride to form liquid lithium deuteride and then extracting the gaseous deuterium from the liquid lithium deuteride.

  2. PRODUCTION OF ALL THE r-PROCESS NUCLIDES IN THE DYNAMICAL EJECTA OF NEUTRON STAR MERGERS

    SciTech Connect

    Wanajo, Shinya; Sekiguchi, Yuichiro; Kiuchi, Kenta; Shibata, Masaru; Nishimura, Nobuya; Kyutoku, Koutarou

    2014-07-10

    Recent studies suggest that binary neutron star (NS-NS) mergers robustly produce heavy r-process nuclei above the atomic mass number A ∼ 130 because their ejecta consist of almost pure neutrons (electron fraction of Y {sub e} < 0.1). However, the production of a small amount of the lighter r-process nuclei (A ≈ 90-120) conflicts with the spectroscopic results of r-process-enhanced Galactic halo stars. We present, for the first time, the result of nucleosynthesis calculations based on the fully general relativistic simulation of a NS-NS merger with approximate neutrino transport. It is found that the bulk of the dynamical ejecta are appreciably shock-heated and neutrino processed, resulting in a wide range of Y {sub e} (≈0.09-0.45). The mass-averaged abundance distribution of calculated nucleosynthesis yields is in reasonable agreement with the full-mass range (A ≈ 90-240) of the solar r-process curve. This implies, if our model is representative of such events, that the dynamical ejecta of NS-NS mergers could be the origin of the Galactic r-process nuclei. Our result also shows that radioactive heating after ∼1 day from the merging, which gives rise to r-process-powered transient emission, is dominated by the β-decays of several species close to stability with precisely measured half-lives. This implies that the total radioactive heating rate for such an event can be well constrained within about a factor of two if the ejected material has a solar-like r-process pattern.

  3. Production of All the r-process Nuclides in the Dynamical Ejecta of Neutron Star Mergers

    NASA Astrophysics Data System (ADS)

    Wanajo, Shinya; Sekiguchi, Yuichiro; Nishimura, Nobuya; Kiuchi, Kenta; Kyutoku, Koutarou; Shibata, Masaru

    2014-07-01

    Recent studies suggest that binary neutron star (NS-NS) mergers robustly produce heavy r-process nuclei above the atomic mass number A ~ 130 because their ejecta consist of almost pure neutrons (electron fraction of Y e < 0.1). However, the production of a small amount of the lighter r-process nuclei (A ≈ 90-120) conflicts with the spectroscopic results of r-process-enhanced Galactic halo stars. We present, for the first time, the result of nucleosynthesis calculations based on the fully general relativistic simulation of a NS-NS merger with approximate neutrino transport. It is found that the bulk of the dynamical ejecta are appreciably shock-heated and neutrino processed, resulting in a wide range of Y e (≈0.09-0.45). The mass-averaged abundance distribution of calculated nucleosynthesis yields is in reasonable agreement with the full-mass range (A ≈ 90-240) of the solar r-process curve. This implies, if our model is representative of such events, that the dynamical ejecta of NS-NS mergers could be the origin of the Galactic r-process nuclei. Our result also shows that radioactive heating after ~1 day from the merging, which gives rise to r-process-powered transient emission, is dominated by the β-decays of several species close to stability with precisely measured half-lives. This implies that the total radioactive heating rate for such an event can be well constrained within about a factor of two if the ejected material has a solar-like r-process pattern.

  4. 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.

  5. 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.

  6. Anisotropic alpha decay from oriented odd-mass isotopes of some light actinides

    SciTech Connect

    Berggren, T. )

    1994-11-01

    Half-lives and anisotropies in the [alpha] decay of [sup 205,207,209]Rn, [sup 219]Rn, [sup 221]Fr, [sup 227,229]Pa, and [sup 229]U have been calculated using the reaction-theoretical formalism proposed by Jackson and Rhoades-Brown and adapted for axially symmetric deformed nuclei by Berggren and Olanders. The possibility of octupole deformation has been taken into account. In addition, a variant of triaxial octupole deformation has been considered tentatively in the case of [sup 227]Pa and [sup 229]Pa.

  7. Projected shell model study of yrast states of neutron-deficient odd-mass Pr nuclei

    SciTech Connect

    Ibanez-Sandoval, A.; Ortiz, M. E.; Velazquez, V.; Galindo-Uribarri, A.; Hess, P. O.; Sun, Y.

    2011-03-15

    A wide variety of modern instruments allow us to study neutron-deficient nuclei in the A=130 mass region. Highly deformed nuclei have been found in this region, providing opportunities to study the deformed rotational bands. The description of the {sup 125,127,129,131,133}Pr isotopes with the projected shell model is presented in this paper. Good agreement between theory and experiment is obtained and some characteristics are discussed, including the dynamic moment of inertia J{sup (2)}, kinetic moment of inertia J{sup (1)}, the crossing of rotational bands, and backbending effects.

  8. Projected Shell Model Study of Yrast States of Neutron-Deficient Odd-Mass Pr Nuclei

    SciTech Connect

    Ibanes, A.; Ortiz, Mark E; Velazquez, V.; Galindo-Uribarri, Alfredo {nmn}; Hess, P. O.; Sun, Y.

    2011-01-01

    A wide variety of modern instruments allow us to study neutron-deficient nuclei in the A = 130 mass region. Highly deformed nuclei have been found in this region, providing opportunities to study the deformed rotational bands. The description of the 125,127,129,131,133Pr isotopes with the projected shell model is presented in this paper. Good agreement between theory and experiment is obtained and some characteristics are discussed, including the dynamic moment of inertia J (2), kinetic moment of inertia J (1), the crossing of rotational bands, and backbending effects.

  9. Shape coexistence in neutron-rich odd-mass S isotopes

    NASA Astrophysics Data System (ADS)

    Mijatovic, Tea; Kobayashi, Nobuyuki; Iwasaki, Hiro; Loelius, Charles; Whitmore, Kenneth; Elder, Robert; Gade, Alexandra; Bazin, Daniel; Weisshaar, Dirk; Bender, Peter; Belarge, Joe; Lunderberg, Eric; Elman, Brandon; Longfellow, Brenden; Dewald, Alfred; Haylett, Thoryn; Mathry, Michael; Heil, Sebastian

    2017-01-01

    Collective motions in atomic nuclei at low excitation energies have been characterized by the ground-state shape as a single basis. This picture can be altered in exotic nuclei with unusual proton-to-neutron ratios if the nuclear shape can change drastically at low spin. Recently, there has been an increasing interest for shape-coexistence phenomena in neutron-rich S isotopes and studies suggested fairly large collectivity in 40 , 42 , 44S isotopes. We will discuss the search for isomeric or long-lived states in 45S for which no excited states are known in the literature and the pursuit to fully characterize the band structure of the low-lying states in 43,45S, which provide key information to establish a comprehensive picture of the shape coexistence in this region. Direct model-independent measurements of the 43,45S excited states were realized by applying the Recoil Distance Method with the TRIPLEX Plunger in conjunction with GRETINA to fast rare isotope beams at the NSCL.

  10. Shape trends and triaxiality in neutron-rich odd-mass Y and Nbisotopes

    SciTech Connect

    Luo, Y.X.; Rasmussen, J.O.; Gelberg, A.; Stefanescu, I.; Hamilton, J.H.; Ramayya, A.V.; Hwang, J.K.; Zhu, S.J.; Gore, P.M.; Fong,D.; Jones, E.F.; Wu, S.C.; Lee, I.Y.; Ginter, T.N.; Ma, W.C.; Ter-Akopian, G.M.; Daniel, A.V.; Stoyer, M.A.; Donangelo, R.

    2004-09-28

    New level schemes of Y and Nb isotopes are proposed based on measurements of prompt gamma rays from 252Cf fission at Gammasphere. Shape trends regarding triaxiality and quadrupole deformations are studied.

  11. Study of rotational bands and electromagnetic properties of odd mass 153-159Eu

    NASA Astrophysics Data System (ADS)

    Pandit, Rakesh K.; Slathia, Barun; Devi, Rani; Khosa, S. K.

    Some positive and negative parity energy bands of odd-A isotopes of Europium 153-159Eu have been studied within the Projected Shell Model (PSM) framework. Calculated excitation energy spectra, transition energies, E2 and M1 transition probabilities, quadrupole and magnetic moments are compared with experimental data wherever available. Reasonably good agreement is obtained with the observed data.

  12. Removal of Radioactive Nuclides by Multi-Functional Microcapsules Enclosing Inorganic Ion-Exchangers and Organic Extractants

    SciTech Connect

    Mimura, H.; Akiba, K.; Onodera, Y.

    2002-02-26

    The microcapsules enclosing two kinds of functional materials, inorganic ion-exchangers and organic extractants, were prepared by taking advantage of the high immobilization ability of alginate gel polymer. The fine powders of inorganic ion-exchanger and oil drops of extractant were kneaded with sodium alginate (NaALG) solution and the kneaded sol readily gelled in a salt solution of CaCl2, BaCl2 or HCl to form spherical gel particles. The uptake properties of various nuclides, 137Cs, 85Sr, 60Co, 88Y, 152Eu and 241Am, for thirty-four specimens of microcapsules in the presence of 10-1-10-4 M HNO3 were evaluated by the batch method. The distribution coefficient (Kd) of Cs+ above 103 cm3/g was obtained for the microcapsules enclosing CuFC or AMP. The Kd of Sr2+ around 102 cm3/g was obtained for the microcapsules containing clinoptilolite, antimonic acid, zeolite A, zeolite X or titanic acid. The microcapsules enclosing DEHPA exhibited relatively large Kd values of trivalent metal ions above 103 cm3/g; for example, the Kd values of Cs+, Sr2+, Co2+, Y3+, Eu3+ and Am3+ for a favorable microcapsule (CuFC/clinoptilolite/DEHPA/CaALG) were 1.1x104, 7.5x10, 1.1x10, 1.0x104, 1.4x104, 3.4x103 cm3/g, respectively. The uptake rates of Cs+, Y3+, Eu3+ and Am3+ for this microcapsule were rather fast; the uptake percentage above 90% was obtained after 19 h-shaking and the uptake equilibrium was attained within 1 d. The AMP/CaALG exhibited high uptake ability for Cs+ even after irradiation of 188 kGy, and DEHPA/CaALG microcapsule had similar Kd values of Cs+, Sr2+, Co2+, Y3+, Eu3+ and Am3+ ions before and after irradiation. The microcapsules with various shapes such as spherical, columnar, fibrous and filmy forms were easily prepared by changing the way of dipping kneaded sol into gelling salt solution. The microcapsules enclosing inorganic ion-exchangers and extractants have a potential possibility for the simultaneous removal of various radioactive nuclides from waste solutions.

  13. Data and software tools for gamma radiation spectral threat detection and nuclide identification algorithm development and evaluation

    NASA Astrophysics Data System (ADS)

    Portnoy, David; Fisher, Brian; Phifer, Daniel

    2015-06-01

    spectral data at 1 s time intervals, which represents data collected by a mobile system operating in a dynamic radiation background environment; and one that represents static measurements with a foreground spectrum (background plus source) and a background spectrum. These data include controlled variations in both Source Related Factors (nuclide, nuclide combinations, activities, distances, collection times, shielding configurations, and background spectra) and Detector Related Factors (currently only gain shifts, but resolution changes and non-linear energy calibration errors will be added soon). The software tools will allow the developer to evaluate the performance impact of each of these factors. Although this first implementation is somewhat limited in scope, considering only NaI-based detection systems and two application domains, it is hoped that (with community feedback) a wider range of detector types and applications will be included in the future. This article describes the methods used for dataset creation, the software validation/performance measurement tools, the performance metrics used, and examples of baseline performance.

  14. Glacial Erosion Rates from Bayesian Inversion of Cosmogenic Nuclide Concentrations in a Bedrock Core, Streaked Mtn., ME

    NASA Astrophysics Data System (ADS)

    Ploskey, Z. T.; Stone, J. O.

    2014-12-01

    Glacial erosion is an important source of sediment and could be an important coupling to glacier and ice sheet models that track sediment. However, glacial erosion is difficult to quantify, and models of glacial erosion can benefit from independent erosion rate estimates. Here we present the results of a Bayesian Markov chain Monte Carlo (MCMC) inversion of a cosmogenic nuclide (CN) geomorphic model for glacial erosion rates on a bedrock landform formerly eroded beneath the Laurentide ice sheet. The CN 10Be was measured in quartz to 8 m depth in a bedrock core from the summit of Streaked Mountain, ME. The accumulation of 10Be was modeled over multiple glacial cycles of alternating exposure and glacial erosion. This model was invertedfor glacial erosion rates and burial history using MCMC algorithms implemented in PyMC (Patil et al., 2010). This Bayesian approach allows us to incorporate prior constraints on ice cover history, including oxygen isotope records and radiometric dates, which is otherwise difficult to differentiate from erosion in rapidly eroding areas. We compare these results to depth profile and surface CN measurements elsewhere in Maine (Ploskey and Stone, 2013).The forward model of CN production used in the inversion is part of Cosmogenic (github.com/cosmolab/cosmogenic), an open-source Python-based software library we developed for modeling the growth and decay of in-situ CN inventories in rock during geomorphic evolution. It includes calibrated production rates for 10Be and 26Al in quartz and 36Cl in K-feldspar by both neutrons and muons, with more isotopic production pathways and material targets to be added in the future. Production rates are scaled to the site altitude and latitude using modular scaling schemes. Cosmogenic includes a variety of functions representing common geomorphic histories, and can be used to model any arbitrary exposure, erosion and burial history that can be defined as Python function.ReferencesPatil, A., D. Huard and C

  15. Calculating Subsurface Nucleonic Production of Noble Gas Nuclides: Implications on Crustal and Mantle K, Th, U Abundances

    NASA Astrophysics Data System (ADS)

    Sramek, O.; McDonough, W. F.; Mukhopadhyay, S.; Stevens, L.; Siegel, J.

    2013-12-01

    While atmospheric concentration of some noble gas nuclides is controlled by their cosmogenic production (e.g., 39Ar), nucleonic production dominates in subsurface environments. Nucleogenic production rates, which involve alpha-induced reactions, depend on Th and U abundances in the source rock. Production rates of 39Ar and 40Ar scale with K abundance in the source. Consequently, observed isotopic ratio of noble gas in crustal fluids and mantle-derived lavas can be compared to calculated predictions in order to constrain heat producing element abundances in the source rock. In particular, 39Ar/40Ar, 39Ar/21Ne, and 40Ar/21Ne inform us about U+Th abundance, K abundance, and K/U ratio. We calculate subsurface production rates for these nuclides for various assumed rock compositions. A discrepancy in existing evaluations of 39Ar production rates is noted. While Mei et al. (2010) predict a production rate of 5 atoms of 39Ar per kg per year for a K=2 %, Th=5 ppm, U=2 ppm (by weight) rock, Yokochi et al. (2012) evaluate 39Ar production rate, in number of atoms / (kg yr), at 24, and Yokochi et al. (2013) results range between 50-80. Efforts are underway to understand these differences. Experimental methods of 39Ar counting have advanced significantly in recent years, a development driven to large extent by the needs of experimental particle physics community in their search for dark matter using argon-based WIMP detectors. Measurement techniques now allow determination of 39Ar/40Ar ratios in crustal rocks and are approaching the detectability of 39Ar/40Ar ratio predicted for a mantle source. We discuss how the noble gas ratio measurements can be harnessed to gain insight into source rock's abundances of heat producing elements including mantle K/U ratio. Mei, D.-M. et al., 2010. Phys. Rev. C 81, 055802, doi:10.1103/PhysRevC.81.055802 Yokochi, R. et al., 2012. Geochim. Cosmochim. Acta 88, 19-26, doi:10.1016/j.gca.2012.04.034 Yokochi, R. et al., 2013. Chem. Geol. 339, 43

  16. Mass measurements on stable nuclides in the rare-earth region with the Penning-trap mass spectrometer TRIGA-TRAP

    SciTech Connect

    Ketelaer, J.; Audi, G.; Beyer, T.; Blaum, K.; Block, M.; Dworschak, M.; Herfurth, F.; Cakirli, R. B.; Casten, R. F.; Droese, C.; Eberhardt, K.; Eibach, M.; Smorra, C.; Minaya Ramirez, E.; Nagy, Sz.; Neidherr, D.; Noertershaeuser, W.; Wang, M.

    2011-07-15

    The masses of 15 stable nuclides in the rare-earth region have been measured with the Penning-trap mass spectrometer TRIGA-TRAP. This is the first series of absolute mass measurements linking these nuclides to the atomic-mass standard {sup 12}C. Previously, nuclear reaction studies almost exclusively determined the literature values of these masses in the Atomic-Mass Evaluation. The TRIGA-TRAP results show deviations on the order of 3-4 standard deviations from the latest published values of the Atomic-Mass Evaluation 2003 for some cases. However, the binding-energy differences that are important for nuclear structure studies have been confirmed and improved. The new masses are discussed in the context of valence proton-neutron interactions using double differences of binding energies, {delta}V{sub pn}(Z,N).

  17. Heavy-ion dosimetry

    SciTech Connect

    Schimmerling, W.

    1980-03-01

    This lecture deals with some of the more important physical characteristics of relativistic heavy ions and their measurement, with beam delivery and beam monitoring, and with conventional radiation dosimetry as used in the operation of the BEVALAC biomedical facility for high energy heavy ions (Lyman and Howard, 1977; BEVALAC, 1977). Even so, many fundamental aspects of the interaction of relativistic heavy ions with matter, including important atomic physics and radiation chemical considerations, are not discussed beyond the reminder that such additional understanding is required before an adequte perspective of the problem can be attained.

  18. Weathering histories of Chinese loess deposits based on uranium and thorium series nuclides and cosmogenic {sup 10}Be

    SciTech Connect

    Gu, Z.Y. |; Lal, D.; Liu, T.S.

    1997-12-01

    The long, continuous deposition of dust in the Chinese loess plateau offers an unique opportunity to study the nature of soil weathering in a wide range of climatic conditions. In this paper we report on measurements of concentrations of U- and Th-series nuclides and of major cations in 150 loess and paleosol samples from five sites, going back 2.5 Ma. Using the results for {sup 10}Be concentrations in these soils, we determined the absolute amounts of water added to several soil units and obtained: (1) first-order leaching constants for U and several cations and (2) the compositions of the soils contributing to the dust-source regions and of the dust at deposition. Further, based on analyses of {sup 230}Th in soils deposited in the past ca. 140 ka, we determined when the soils weathered in the source regions. We conclude that most of the weathering in the dust-source regions may have occurred during the interglacials. 34 refs., 8 figs., 2 tabs.

  19. TRENDS (Transport and Retention of Nuclides in Dominant Sequences): A code for modeling iodine behavior in containment during severe accidents

    SciTech Connect

    Weber, C.F.; Beahm, E.C.; Kress, T.S.; Daish, S.R.; Shockley, W.E.

    1989-01-01

    The ultimate aim of a description of iodine behavior in severe LWR accidents is a time-dependent accounting of iodine species released into containment and to the environment. Factors involved in the behavior of iodine can be conveniently divided into four general categories: (1) initial release into containment, (2) interaction of iodine species in containment not directly involving water pools, (3) interaction of iodine species in, or with, water pools, and (4) interaction with special systems such as ice condensers or gas treatment systems. To fill the large gaps in knowledge and to provide a means for assaying the iodine source term, this program has proceeded along two paths: (1) Experimental studies of the chemical behavior of iodine under containment conditions. (2) Development of TRENDS (Transport and Retention of Nuclides in Dominant Sequences), a computer code for modeling the behavior of iodine in containment and its release from containment. The main body of this report consists of a description of TRENDS. These two parts to the program are complementary in that models within TRENDS use data that were produced in the experimental program; therefore, these models are supported by experimental evidence that was obtained under conditions expected in severe accidents. 7 refs., 1 fig., 2 tabs.

  20. Prompt neutron emission multiplicity distributions and average values, /bar char/. nu. , at 2200 meter per second for the fissile nuclides

    SciTech Connect

    Holden, N.E.; Zucker, M.S.

    1988-01-01

    The prompt neutron emission multiplicity distribution, P/sub nu/ is of interest for methods of self-calibration and for auto-correlation to assay fissionable material for nuclear safeguards. /bar char/..nu.., the average value of P/sub nu/, is of interest at neutron thermal energies since it is used as a normalizing point for energy dependent values of /bar char/..nu... Values of P/sub nu/ and /bar char/..nu.. have been determined at the standard neutron energy of 0.0253 ev for the neutron induced fission of the four fissile nuclides, /sup 233,235/U, and /sup 239,241/Pu. Revised /bar char/..nu.. values have been obtained by re-evaluating /bar char/..nu.. experiments measured at 2200 meter/second relative to the /bar char/..nu.. from the spontaneous fission of /sup 252/Cf. These revised values of /bar char/..nu.. been used to renormalize the measured P/sub nu/ values. The revised values of /bar char/..nu.. are all about 1/4% to 1/2% smaller than the corresponding values of ENDF/B-V. 25 refs., 4 tabs.

  1. Pliocene Cosmogenic Nuclide Burial Ages of the Nenana Gravel: Progress in Dating and Implications for Alaska Range Evolution

    NASA Astrophysics Data System (ADS)

    Goehring, B. M.; Bemis, S. P.; Ward, D.; Caffee, M. W.; Sortor, R. N.

    2015-12-01

    The Nenana Gravel is an up to 1.2 km thick foreland basin deposit that spans the north flank of the Alaska Range. It is uplifted relative to the active foreland basin to the north. It is also deformed to various degree dependent on its location within the northern Alaska Range thrust system. Because this foreland basin sequence records the unroofing and northward propagation of the Alaska Range, direct dating of the Nenana Gravel, especially over wide spatial distribution along the Alaska Range, will substantially advance our understanding of the style and timing of deformation of the Alaska Range. At present though, age estimates for the Nenana Gravel are limited to a single maximum limiting age and uncertain minimum limiting age with no little or no insight as to the spatial variation in Nenana Gravel deposition timing. We present the first direct dates of deposition ages of the Nenana Gravel using cosmogenic nuclide burial dating. Results indicate that deposition of the Nenana Gravel began ca. 6.5 Ma, in stratigraphic agreement with a maximum limiting tephra age from the underlying Usibelli Group. Additional samples from the Nenana Gravel basal contact and higher in the section are presently underway. The resultant burial ages are amongst the oldest 26Al-10Be burial ages ever produced and highlight the potential of the method to directly date sediments in the Pliocene, particularly given recent advancements in the accelerator mass spectrometry measurement of 26Al/27Al isotope ratios.

  2. Terrestrial cosmogenic nuclide surface exposure dating of the oldest glacial successions in the Himalayan orogen: Ladakh Range, northern India

    USGS Publications Warehouse

    Owen, L.A.; Caffee, M.W.; Bovard, K.R.; Finkel, R.C.; Sharma, M.C.

    2006-01-01

    Terrestrial cosmogenic nuclide surface exposure dating of moraine boulders and alluvial fan sediments define the timing of five glacial advances over at least the last five glacial cycles in the Ladakh Range of the Transhimalaya. The glacial stages that have been identified are: the Indus Valley glacial stage, dated at older than 430 ka; the Leh glacial stage occurring in the penultimate glacial cycle or older; the Karglacial stage, occurring during the early part of the last glacial cycle; the Bazgo glacial stage, at its maximum during the middle of the last glacial cycle; and the early Holocene Khalling glacial stage. The exposure ages of the Indus Valley moraines are the oldest observed to date throughout the Himalayan orogen. We observe a pattern of progressively more restricted glaciation during the last five glacial cycles, likely indicating a progressive reduction in the moisture supply necessary to sustain glaciation. A possible explanation is that uplift of Himalayan ranges to the south and/or of the Karakoram Mountains to the west of the region may have effectively blocked moisture supply by the south Asian summer monsoon and mid-latitude westerlies, respectively. Alternatively, this pattern of glaciation may reflect a trend of progressively less extensive glaciation in mountain regions that has been observed globally throughout the Pleistocene. ?? 2006 Geological Society of America.

  3. G4MoNA - A Geant4 Simulation for unbound nuclides detected with MoNA/LISA

    NASA Astrophysics Data System (ADS)

    Gueye, Paul; Freeman, Jessica; Frank, Nathan; MoNA Collaboration

    2017-01-01

    The MoNA Collaboration has conducted a plethora of experiments to study unbound nuclei near the neutron dripline using the invariant mass technique since 2005. These experiments used a variety of secondary beams from the Coupled Cyclotron Facility of the National Superconducting Cyclotron Laboratory. The experimental setup consists of a large gap superconducting Sweeper magnet for charged fragments separation and the MoNA/LISA neutron detector arrays for neutron detection. Recently, a multi-layered Si/Be segmented target consisting of three 700 mg/cm2 thick 9Be slabs and four 140 μ m Si detectors were added to the setup. This target improves the resolution of the reconstructed decay energy spectra of the unbound nuclides. The Geant4 Monte Carlo simulation toolkit was used to develop a complete realistic model of the setup including a new class to treat the decay of unbound nuclei, the Si/Be segmented target, the MoNA/LISA and the charged fragments detector systems. Comparison between simulated and experimental data will be presented. DoENNSA - DE-NA0000979.

  4. Heavy Menstrual Bleeding

    MedlinePlus

    ... to pregnancy, such as ectopic pregnancy and miscarriage . Pelvic inflammatory disease also can cause heavy menstrual bleeding. Sometimes, the ... A physical examination of a woman’s reproductive organs. Pelvic Inflammatory Disease: An infection of the uterus, fallopian tubes, and ...

  5. Heavy fermion quantum criticality.

    PubMed

    Nazario, Zaira; Santiago, David I

    2008-09-26

    During the last few years, investigations of rare-earth materials have made clear that heavy fermion quantum criticality exhibits novel physics not fully understood. In this work, we write for the first time the effective action describing the low energy physics of the system. The f fermions are replaced by a dynamical scalar field whose nonzero expected value corresponds to the heavy fermion phase. The effective theory is amenable to numerical studies as it is bosonic, circumventing the fermion sign problem. Via effective action techniques, renormalization group studies, and Callan-Symanzik resummations, we describe the heavy fermion criticality and predict the heavy fermion critical dynamical susceptibility and critical specific heat. The specific heat coefficient exponent we obtain (0.39) is in excellent agreement with the experimental result at low temperatures (0.4).

  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. Physical particularities of nuclear reactors using heavy moderators of neutrons

    SciTech Connect

    Kulikov, G. G. Shmelev, A. N.

    2016-12-15

    In nuclear reactors, thermal neutron spectra are formed using moderators with small atomic weights. For fast reactors, inserting such moderators in the core may create problems since they efficiently decelerate the neutrons. In order to form an intermediate neutron spectrum, it is preferable to employ neutron moderators with sufficiently large atomic weights, using {sup 233}U as a fissile nuclide and {sup 232}Th and {sup 231}Pa as fertile ones. The aim of the work is to investigate the properties of heavy neutron moderators and to assess their advantages. The analysis employs the JENDL-4.0 nuclear data library and the SCALE program package for simulating the variation of fuel composition caused by irradiation in the reactor. The following main results are obtained. By using heavy moderators with small neutron moderation steps, one is able to (1) increase the rate of resonance capture, so that the amount of fertile material in the fuel may be reduced while maintaining the breeding factor of the core; (2) use the vacant space for improving the fuel-element properties by adding inert, strong, and thermally conductive materials and by implementing dispersive fuel elements in which the fissile material is self-replenished and neutron multiplication remains stable during the process of fuel burnup; and (3) employ mixtures of different fertile materials with resonance capture cross sections in order to increase the resonance-lattice density and the probability of resonance neutron capture leading to formation of fissile material. The general conclusion is that, by forming an intermediate neutron spectrum with heavy neutron moderators, one can use the fuel more efficiently and improve nuclear safety.

  8. Physical particularities of nuclear reactors using heavy moderators of neutrons

    NASA Astrophysics Data System (ADS)

    Kulikov, G. G.; Shmelev, A. N.

    2016-12-01

    In nuclear reactors, thermal neutron spectra are formed using moderators with small atomic weights. For fast reactors, inserting such moderators in the core may create problems since they efficiently decelerate the neutrons. In order to form an intermediate neutron spectrum, it is preferable to employ neutron moderators with sufficiently large atomic weights, using 233U as a fissile nuclide and 232Th and 231Pa as fertile ones. The aim of the work is to investigate the properties of heavy neutron moderators and to assess their advantages. The analysis employs the JENDL-4.0 nuclear data library and the SCALE program package for simulating the variation of fuel composition caused by irradiation in the reactor. The following main results are obtained. By using heavy moderators with small neutron moderation steps, one is able to (1) increase the rate of resonance capture, so that the amount of fertile material in the fuel may be reduced while maintaining the breeding factor of the core; (2) use the vacant space for improving the fuel-element properties by adding inert, strong, and thermally conductive materials and by implementing dispersive fuel elements in which the fissile material is self-replenished and neutron multiplication remains stable during the process of fuel burnup; and (3) employ mixtures of different fertile materials with resonance capture cross sections in order to increase the resonance-lattice density and the probability of resonance neutron capture leading to formation of fissile material. The general conclusion is that, by forming an intermediate neutron spectrum with heavy neutron moderators, one can use the fuel more efficiently and improve nuclear safety.

  9. ESB Heavy Lift Requirements

    DTIC Science & Technology

    2006-01-01

    capacity, cross-country travel ability, and redundancy than the three axles and twelve tires found on the M870 trailer.13,14 In fact, this...equates to an organic ability to move approximately twenty- three percent of the battalion’s heavy equipment that requires prime movers in one lift...Truck Tractor manufactured by Oshkosh Truck Corporation and the M1000 Heavy Equipment Transporter semi-trailer manufactured by Systems

  10. Process for removing heavy metal compounds from heavy crude oil

    DOEpatents

    Cha, Chang Y.; Boysen, John E.; Branthaver, Jan F.

    1991-01-01

    A process is provided for removing heavy metal compounds from heavy crude oil by mixing the heavy crude oil with tar sand; preheating the mixture to a temperature of about 650.degree. F.; heating said mixture to up to 800.degree. F.; and separating tar sand from the light oils formed during said heating. The heavy metals removed from the heavy oils can be recovered from the spent sand for other uses.

  11. From source to sink with in situ cosmogenic nuclides: Modern to late Holocene denudation rates and sediment fluxes in the Po basin

    NASA Astrophysics Data System (ADS)

    Wittmann, Hella; Malusà, Marco; Resentini, Alberto; Garzanti, Eduardo; Niedermann, Samuel

    2017-04-01

    Cosmogenic nuclides are now established as an integral tool of Earth surface science, providing reliable measures of landscape change. Applications of in situ-produced nuclides to lowland basins, where sediment undergoes storage and deposition, are however still rare. Recently, it was shown for large cratonic river basins that cosmogenic nuclides can provide an integrated approach insensitive to a range of geological sources of bias thereby tracing signals from upstream mountainous areas to the lowlands (summary given in [1]). Given these advances of the method, we can proceed with the application to a geologically complex subsiding foreland basin. In the Po basin, we constrained the long-term sediment delivery from source to deltaic sink using sediment fluxes from in situ 10Be-derived denudation rates and compared these to published short-term estimates from gauging. From the comparison of 10Be nuclide data measured upstream of dam influence to those measured downstream of major dams, we find that the average 10Be signal is not significantly modified. In the lowland reaches, we find that the average 10Be concentration is only marginally modified by floodplain processes, as 26Al/10Be ratios do not show differential decay due to burial. The close similarity in 10Be concentrations from the sources to the Po lowland sink suggests that LGM denudation rates prior to sediment trapping in periglacial lakes were similar to today's, as the sediment now contained in the Po lowlands must have been eroded from the orogen and deposited in the lowlands prior to lake formation. Todaýs sediment in the Alpine and Apenninic source areas erodes at 10Be-derived rates ranging from 0.1-1.5 mm/yr in the Alpine and from 0.25-0.5 mm/yr in the Apenninic source areas. The highest 10Be-derived denudation rates are found in the western Central Alps (1.5 mm/yr), where also recent uplift rates are among the highest. From these data, we constrain a total cosmogenic-derived sediment flux leaving

  12. Contribution of Paleomagnetic and Cosmogenic Nuclide Production Records to Solve the Question of Orbital Constraint on the Geodynamo

    NASA Astrophysics Data System (ADS)

    Thouveny, N.; Ménabréaz, L.; Bourles, D. L.; Demory, F.; Guillou, V.; Arnold, M.; Magorb Team

    2013-05-01

    The contribution of axial precession to the geodynamo energy budget recently rebounded with the demonstrations through theoretical and experimental studies that its amount of energy had been underestimated, while on the contrary the energy required to disturb the geodynamo was overestimated (e.g. Vanyo, 2004, Roberts et Wu, 2005, Tilgner 2005). Paleomagnetic tests of such an hypothesis remain yet highly controversial because relative paleointensity reconstructions are suspected of paleoenvironmental biases. Many available indicators [i) depositional remanent magnetization of sediment (paleodirections and paleointensity), ii) magnetization of the deep sea floor basalts, iii) geochemical records of cosmogenic nuclides production rates] however converge to produce a robust series of geomagnetic dipole lows related to paleomagnetic excursions of the last Ma. These series evidence periodicities in the 30 kyr-120 kyr range and present phase relationships with obliquity variations and δ18O records. Yet, such paleomagnetic time series are presently not precise and complete enough to firmly validate such fundamental but still hypothetic relationship. To further contribute solving this issue, the MAG-ORB project, funded for a 4 years period by the French Agence Nationale de la Recherche, aims at reconstructing the time series of the geomagnetic dipole lows over the last 2 Ma using paleomagnetism coupled with cosmogenic nuclide 10Be and lithogenic 9Be isotopes measurements on sedimentary cores from mid and low latitudes, i.e. where the geomagnetic modulation of the cosmic ray penetration is the most efficient. New results (Ménabréaz et al., 2011; 2012; Ménabréaz, 2012) confirm and complete former results (Carcaillet et al., 2003; 2004) to demonstrate that over the last 1.2 Ma the excursions and reversals, and their respective relative paleointensity lows, are accompanied by significant enhancements of the cosmogenic 10Be production rate, pointing out a global collapse of

  13. ANEMOS: A computer code to estimate air concentrations and ground deposition rates for atmospheric nuclides emitted from multiple operating sources

    SciTech Connect

    Miller, C.W.; Sjoreen, A.L.; Begovich, C.L.; Hermann, O.W.

    1986-11-01

    This code estimates concentrations in air and ground deposition rates for Atmospheric Nuclides Emitted from Multiple Operating Sources. ANEMOS is one component of an integrated Computerized Radiological Risk Investigation System (CRRIS) developed for the US Environmental Protection Agency (EPA) for use in performing radiological assessments and in developing radiation standards. The concentrations and deposition rates calculated by ANEMOS are used in subsequent portions of the CRRIS for estimating doses and risks to man. The calculations made in ANEMOS are based on the use of a straight-line Gaussian plume atmospheric dispersion model with both dry and wet deposition parameter options. The code will accommodate a ground-level or elevated point and area source or windblown source. Adjustments may be made during the calculations for surface roughness, building wake effects, terrain height, wind speed at the height of release, the variation in plume rise as a function of downwind distance, and the in-growth and decay of daughter products in the plume as it travels downwind. ANEMOS can also accommodate multiple particle sizes and clearance classes, and it may be used to calculate the dose from a finite plume of gamma-ray-emitting radionuclides passing overhead. The output of this code is presented for 16 sectors of a circular grid. ANEMOS can calculate both the sector-average concentrations and deposition rates at a given set of downwind distances in each sector and the average of these quantities over an area within each sector bounded by two successive downwind distances. ANEMOS is designed to be used primarily for continuous, long-term radionuclide releases. This report describes the models used in the code, their computer implementation, the uncertainty associated with their use, and the use of ANEMOS in conjunction with other codes in the CRRIS. A listing of the code is included in Appendix C.

  14. Are Scaling Models for Production of Cosmogenic Nuclides Isotope Specific? - Implications from Secondary Cosmic Ray Neutron Spectra Measurements

    NASA Astrophysics Data System (ADS)

    Wilcken, K.

    2015-12-01

    A necessary requirement in studies using in-situ cosmogenic isotopes is to convert the measured isotope concentrations to exposure ages or geomorphic process rates. This involves using an accepted reference production rate, derived experimentally at a calibration site that has independent age control, and applying scaling factors for latitude and altitude in order to calculate a site-specific production rate. Throughout the development of the in-situ cosmogenic dating method, although reference production rates are necessarily nuclide specific, the scaling factors were not. The first atmospheric scaling model by Lal and Peters [1967] and others that followed, were based on the principle that as the cosmic ray particle flux attenuates with depth, the energy spectrum of nucleons of energy below 400 MeV becomes invariant at atmospheric depths greater than 200 g/cm2(altitude < 12 km). Hence scaling factors would thus be isotope independent resulting in production rate ratios of different isotopes to be invariant as a function of altitude. However, recent models by Argento et al. [2012, 2015] and Lifton et al. [2014] suggest that the energy spectrum is not invariant and scaling factors should in fact be isotope specific. The essential feature of the new models is that the focus is on generating the energy spectrum of cosmic-ray nucleons that is then converted into scaling factors with known cross sections. To benchmark the new scaling models I have collated secondary cosmic-ray neutron spectra measurements from the last 20 years and utilised these to calculate site-specific production rates. When using both ground-based and airborne neutron spectra measurements, the result follows the general trend predicted by the new models requiring isotope specific scaling. In contrast, using only the ground-based measurements, which range from sea-level to ~4000 m in altitude, no evidence for isotope specific scaling is apparent.

  15. Extracting dynamic topography from river profiles and cosmogenic nuclide geochronology in the Middle Atlas and the High Plateaus of Morocco

    NASA Astrophysics Data System (ADS)

    Pastor, Alvar; Babault, Julien; Owen, Lewis A.; Teixell, Antonio; Arboleya, María-Luisa

    2015-11-01

    The Moulouya river system has intensely eroded the Arhbalou, Missour, and Guercif Neogene foreland basins in northeastern Morocco, having changed from net aggradation during the Miocene-early Pliocene to net incision punctuated by alluvial fan deposition at late Pliocene or early Quaternary time. This region as a whole has experienced mantle-driven, surface uplift (dynamic topography) since the late Cenozoic, being locally affected by uplift due to crustal shortening and thickening of the Middle Atlas too. Knickpoints located along the major streams of the Moulouya fluvial network, appear on both the undeformed margins of the Missour and Guercif foreland basins (High Plateaus), as well as along the thrust mountain front of the southern Middle Atlas, where they reach heights of 800-1000 m. 500-550 m of the knickpoint vertical incision might be explained by long-wavelength mantle-driven dynamic surface uplift, whereas the remaining 450-500 m in the southern Middle Atlas front and 200-300 m in the northeastern Middle Atlas front seem to be thrust-related uplift of the Jebel Bou Naceur. Be-10 terrestrial cosmogenic nuclides have been used to date two Quaternary river terraces in the Chegg Ard valley at 62 ± 14 ka and 411 ± 55 ka. The dated terraces allow the incision rates associated with the frontal structures of the Middle Atlas to be estimated at ~ 0.3 mm yr- 1. Furthermore, these ages have served to evaluate mantle-driven regional surface uplift since the middle Pleistocene in the central Missour basin, yielding values of ~ 0.1-0.2 mm yr- 1.

  16. Can cosmogenic nuclides (36Cl) unravel the timing of dislocation of tsunami blocks on Bonaire (Leeward Antilles)?

    NASA Astrophysics Data System (ADS)

    Engel, Max; Rixhon, Gilles; Brückner, Helmut; May, S. Matthias; Binnie, Steve; Dunai, Tibor J.

    2013-04-01

    On Bonaire (Leeward Antilles) and rocky coasts worldwide, high-energy wave events (tsunamis, storms) dislocate coarse-clast deposits (Engel and May, 2012). Using these onshore blocks and boulders to derive ages for the most powerful events on millennial scales is still a major challenge. We apply terrestrial cosmogenic nuclides (TCN), in particular 36Cl, in case of the largest blocks in order to directly date the transport event(s), i.e. the inferred tsunami(s). This dating method has hitherto been disregarded in the coastal environment, particularly in the context of block transport. The following characteristics of the blocks are fundamental for the success of the presented dating approach: (1) due to the lithology (aragonite, calcite), concentration measurements of 36Cl are performed; (2) only large and thick boulders and blocks (>50 t, >2 m thickness) for which tsunami transport was inferred (Engel and May, 2012) were sampled; (3) since the boulders stem from the edge of the coral reef platform, they had been exposed to cosmic radiation prior to the transport event(s) and had already accumulated a certain amount of TCN. To avoid this problem of inheritance, we only sampled the thickest clasts, and those having experienced a 180° overturn during transport; thus, having exposed a "blank" side to cosmic rays only since the event. The complete overturn is attested by the presence of inactive rock pools in upside-down position and bioerosive notches. Engel, M., and May, S. M.: Bonaire's boulder fields revisited: Evidence for Holocene tsunami impact on the Leeward Antilles, Quat. Sci. Rev., 54, 126-141, 2012.

  17. New Insights on Long Term Geomagnetic Moment Variation from Cosmogenic Nuclide and Paleointensity Signatures along Ocean Sediment Cores.

    NASA Astrophysics Data System (ADS)

    Thouveny, N.; Bourles, D. L.; Valet, J. P.; Bassinot, F. C.; Ménabréaz, L.; Simon, Q.; Demory, F.; Valery, G.; Vidal, L.; Beaufort, L.; de Garidel-Thoron, T.

    2015-12-01

    Some numerical and experimental simulations suggest that precession might supply enough power to influence planetary dynamos. The demonstration of a causal relationship between the Earth's orbital motion and variations of the geomagnetic field intensity, would open interesting perspective for modelling the past and future geomagnetic field behaviour and its eventual relationships to past and future orbitally constrained, climatic changes. Although pristine geomagnetic signals can be extracted by filtering and stacking multiple normalized intensity records, the reconstruction of high resolution geomagnetic field variations still raises questions. Namely, significant variance at orbital frequencies in relative paleointensity (RPI) records are generally considered as clues of residual contamination by paleoclimatically induced variations of magnetic carriers size ranges or mineralogy. Such questions can be adressed using other indicators of the geomagnetic dipole moment variation, such as the cosmogenic production modulated by the magnetospheric shielding. During the MAGORB project (ANR-09-BLAN-053-001) cosmogenic nuclide geochemistry, d18O, and paleomagnetic records were constructed along thick clayey-carbonate sequences deposited in the equatorial pacific and indian oceans over the last million of years. Authigenic 10Be/9Be ratio and RPI variations generally exhibit similar ranges of oscillations. However significant offsets appear between some RPI lows and their corresponding 10Be/9Be peaks, suggesting delayed lock-in of the remanent magnetization. After transfer on time scales the new geomagnetic moment series can be compared with the PISO-1500 and SINT-2000 stacks, and with the 10Be ice core record of EPICA Dome C. These new authigenic 10Be/9Be ratio records provide new opportunities to: 1) assess the validity of high resolution RPI records, 2) evaluate address the question of the presence of orbital periods in the paleo-field geomagnetic spectrum, and 3) to

  18. Insights on the post-seismic geomorphological response to the 2008 Wenchuan Earthquake from detrital cosmogenic nuclides data

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Godard, Vincent; Liu-Zeng, Jing; Scherler, Dirk; Xu, Chong; Xu, Quiang; Xie, Kejia; Bellier, Olivier; Ansberque, Claire; de Sigoyer, Julia; Aster Team

    2016-04-01

    In high-relief mountain ranges bounded by reverse faults, large-magnitude earthquakes can contribute to topographic growth by co- and inter-seismic surface uplift of the hanging wall; meanwhile, earthquakes can also lower relief by causing erosion through extensive landslides. Quantifying evacuation process of co-seismic landslides material is central to our understanding of mass redistribution at the earth surface and the evolution of active mountain ranges. The 2008 Mw 7.9 Wenchuan earthquake in the Longmen Shan range of eastern Tibet provides a valuable opportunity to evaluate such direct impact. Cosmogenic nuclides concentrations in river sands are diluted by the input of low-concentration landslide debris materials after the earthquake (West et al., 2014), and we document the evolution 10Be concentrations in quartz for several years after the Wenchuan earthquake to trace the routing processes of co-seismic landslides. Over the 2008-2013 period we collected river sand samples at 19 locations annually along the rivers that flow through the rupture zone. When compared with published pre-earthquake data, our results show that the 10Be concentration in river sand declined dramatically after the earthquake at all sampling sites. Meanwhile, multi-year time series of 10Be concentration at single sites present roughly constant level of dilution with moderate fluctuations. Our analyses indicate that the 10Be dilution amplitude is closely controlled by local catchment slope and landslide density, rather than by the location of landslides with respect to sampling sites. The perturbation we observed for 10Be concentrations in the 0.25~1 mm size fraction appears to be sustained over the timescale of our survey with no clear relaxation, which is consistent with independent results from suspended sediment analysis (Wang et al., 2015).

  19. Heavy-atom derivatization.

    PubMed

    Garman, Elspeth; Murray, James W

    2003-11-01

    Most of the standard methods of solving macromolecular structures involve producing a protein crystal that is derivatized by an anomalous scatterer or heavy atom (MIR, SIRAS, MAD, SAD etc.). The theoretical methodology which underpins the extraction of phase information from such derivatives is widely available in the literature. In addition, there are comprehensive sources of information on the chemistry of heavy-atom compounds and the ligands with which they are known to interact, as well as the Heavy Atom Databank accessible on the World Wide Web. This contribution therefore aims to provide some information on the less well documented practical problems of firstly deciding on an overall strategy for derivatization and secondly performing the physical manipulations involved in producing heavy-atom derivatives from native protein crystals and then cryocooling them. Ways to optimize the chances of isomorphous unit cells are suggested. Methods of determining whether or not the heavy atom is bound are outlined, including the powerful technique of PIXE (particle-induced X-ray emission).

  20. Heavy exotic molecules

    NASA Astrophysics Data System (ADS)

    Liu, Yizhuang; Zahed, Ismail

    We briefly review the formation of pion-mediated heavy-light exotic molecules with both charm and bottom, under the general structures of chiral and heavy quark symmetries. The charm isosinglet exotic molecules with JPC = 1++ binds, which we identify as the reported neutral X(3872). The bottom isotriplet exotic with JPC = 1+- binds, and is identified as a mixed state of the reported charged exotics Zb+(10610) and Zb+(10650). The bound bottom isosinglet molecule with JPC = 1++ is a possible neutral Xb(10532) to be observed.

  1. Heavy exotic molecules

    NASA Astrophysics Data System (ADS)

    Liu, Yizhuang; Zahed, Ismail

    We briefly review the formation of pion-mediated heavy-light exotic molecules with both charm and bottom, under the general structures of chiral and heavy quark symmetries. The charm isosinglet exotic molecules with JPC = 1++ binds, which we identify as the reported neutral X(3872). The bottom isotriplet exotic with JPC = 1+1 binds, and is identified as a mixed state of the reported charged exotics Zb+(10610) and Zb-(10650). The bound bottom isosinglet molecule with JPC = 1++ is a possible neutral Xb(10532) to be observed.

  2. Dolly For Heavy Towbar

    NASA Technical Reports Server (NTRS)

    Soper, Terry A.

    1992-01-01

    Proposed lightweight dolly enables operator to cart heavy towbar to remote site over unpaved roads or rough terrain. Acts as simple, lightweight towed vehicle to support rear of towbar. Removed quickly at point of use. Saves labor, and eliminates need for truck and forklift.

  3. Resonances in heavy systems

    SciTech Connect

    Betts, R.R.

    1983-01-01

    The experimental situation for the study of resonances in heavy-ion collisions is reviewed, with emphasis on the heaviest systems. New data are presented which show some of the systematics of this phenomenon. The narrow resonance structures are established as a feature of the nuclear structure of the composite system rather than a purely entrance channel effect.

  4. Heavy Vehicle Systems

    SciTech Connect

    Sid Diamond; Richard Wares; Jules Routbort

    2000-04-11

    Heavy Vehicle (HV) systems are a necessary component of achieving OHVT goals. Elements are in place for a far-ranging program: short, intermediate, and long-term. Solicitation will bring industrial input and support. Future funding trend is positive, outlook for HV systems is good.

  5. STAR heavy flavor tracker

    NASA Astrophysics Data System (ADS)

    Qiu, Hao

    2014-11-01

    Hadrons containing heavy quarks are a clean probe of the early dynamic evolution of the dense and hot medium created in high-energy nuclear collisions. To explore heavy quark production at RHIC, the Heavy Flavor Tracker (HFT) for the STAR experiment was built and installed in time for RHIC Run 14. The HFT consists of four layers of silicon detectors. The two outermost layers are silicon strip detectors and the two innermost layers are made from state-of-the-art ultra-thin CMOS Monolithic Active Pixel Sensors (MAPS). This is the first application of a CMOS MAPS detector in a collider experiment. The use of thin pixel sensors plus the use of carbon fiber supporting material limits the material budget to be only 0.4% radiation length per pixel detector layer, enabling the reconstruction of low pT heavy flavor hadrons. The status and performance of the HFT in the RHIC 200 GeV Au + Au run in 2014 are reported. Very good detector efficiency, hit residuals and track resolution (DCAs) were observed in the cosmic ray data and in the Au + Au data.

  6. Heavy Quark Fluorescence

    SciTech Connect

    Torres-Rincon, Juan M.; Llanes-Estrada, Felipe J.

    2010-07-09

    Heavy hadrons containing heavy quarks (for example, {Upsilon} mesons) feature a scale separation between the heavy-quark mass and the QCD scale that controls the effective masses of lighter constituents. As in ordinary molecules, the deexcitation of the lighter, faster degrees of freedom leaves the velocity distribution of the heavy quarks unchanged, populating the available decay channels in qualitatively predictable ways. Automatically an application of the Franck-Condon principle of molecular physics explains several puzzling results of {Upsilon}(5S) decays as measured by the Belle Collaboration, such as the high rate of B{sub s}*B{sub s}* versus B{sub s}*B{sub s} production, the strength of three-body B{sup *}B{pi} decays, or the dip in B momentum shown in these decays. We argue that the data show the first Sturm-Liouville zero of the {Upsilon}(5S) quantum-mechanical squared wave function and provide evidence for a largely bb composition of this meson.

  7. Heavy menstrual bleeding.

    PubMed

    Pearce, Lynne

    2016-10-05

    Essential facts Heavy menstrual bleeding (HMB) is defined as excessive menstrual blood loss that interferes with a woman's physical, emotional, social or material quality of life. In England and Wales, around 80,000 women a year will be referred for the first time to secondary care, with 30,000 requiring surgical treatment.

  8. Cosmogenic nuclide and uranium-series dating of old, high shorelines in the western Great Basin, USA

    USGS Publications Warehouse

    Kurth, G.; Phillips, F.M.; Reheis, M.C.; Redwine, J.L.; Paces, J.B.

    2011-01-01

    Closed-basin pluvial lakes are sensitive recorders of effective moisture, and they provide a terrestrial signal of climate change that can be compared to marine and ice records of glacial-interglacial cycles. Although the most recent deep-lake cycle in the western Great Basin (at ca. 16 ka) has been studied intensively, comparatively little is known about the longer-term Quaternary lacustrine history of the region. Lacustrine features higher than those of the most recent highstand have been discovered in many locations throughout the western Great Basin. Qualitative geomorphic and soil studies of shoreline sequences above the latest Pleistocene level suggest that their ages increase as a function of increasing altitude. The results of cosmogenic nuclide dating using chlorine-36 depth profiles from three sites in Nevada (Walker Lake, Columbus Salt Marsh, and Newark Valley), combined with uranium-series and radiocarbon ages, corroborate the geomorphic and soil evidence. The 36Cl results are consistent with available 14C ages and together indicate that the most recent highstands of all three lakes occurred ca. 20-15 ka, late in marine isotope stage (MIS) 2, as shown by previous ages. The 36Cl ages indicate that older lakes in all three basins reached highstands between 100 and 50 ka, and most likely during MIS 4. Shorelines of this age are at about the same or higher altitudes as the younger, MIS 2 shorelines in those basins. The 36Cl results combined with uranium-series ages and one tephra correlation obtained on shorelines higher in altitude than those of MIS 4 and 2 lakes suggest that there were also major lake highstands in the western Great Basin at ca. 100-200 ka, likely corresponding with MIS 6, and during at least two older periods. From these results, we conclude that the preserved shorelines show an apparent decrease in maximum levels with time, suggesting long-term drying of the region since the early middle Pleistocene. ?? 2011 Geological Society of

  9. Early deglaciation of the western sector of the Cordilleran Ice Sheet from cosmogenic nuclide exposure dating, central British Columbia coast

    NASA Astrophysics Data System (ADS)

    Darvill, C.; Menounos, B.; Goehring, B. M.; Lian, O. B.

    2016-12-01

    Reconstructing the retreat of the Cordilleran Ice Sheet (CIS) during the last deglaciation has implications for sea level variability and the peopling of the Americas, but requires robust glacial chronologies. The southern margin of the CIS advanced to its maximum extent at ca. 16 ka, but no directly dated terrestrial limits presently exist on the central coast to constrain the western ice margin prior to ca. 14 ka. Moreover, published marine sediment cores show intervals of ice-rafted debris interpreted to reflect an unstable, marine-terminating western margin that may have rapidly retreated during deglaciation. Here, we present data from two moraines on Calvert Island, British Columbia (51.6°N, 128.1°W) that demarcate the central-western edge of the CIS during deglaciation. The orientation of the moraines suggests that ice flowed southward along the Hugh Sound-Dean Channel fjord system, a major western outlet of the former ice sheet. Terrestrial cosmogenic 10Be nuclide dating of erratic boulders and bedrock associated with a prominent end moraine in the centre of the island yielded a mean weighted exposure age of 16.5 ± 0.3 ka (n=5). Erratic boulders from a second moraine approximately 8 km to the north and 600 m lower in elevation than the first yielded a weighted mean exposure age of 14.2 ± 0.5 ka (n=4). This latter age supports recently reported bracketing radiocarbon ages for stratigraphically equivalent till in a section exposed in the northwest part of the island. We are currently processing twenty-three further 10Be exposure ages from targeted erratics and bedrock to further constrain the timing and extent of deglaciation within this region. Our current data indicate that if the western CIS reached the outer continental shelf it did so prior to ca. 16.5 ka, and was in retreat by the time the southern margin reached its maximum extent. In addition, these new ages indicate that ice free areas existed along the western coast from at least 16.5 ka

  10. 10Be systematics in the Tsangpo-Brahmaputra catchment: the cosmogenic nuclide legacy of the eastern Himalayan syntaxis

    NASA Astrophysics Data System (ADS)

    Lupker, Maarten; Lavé, Jérôme; France-Lanord, Christian; Christl, Marcus; Bourlès, Didier; Carcaillet, Julien; Maden, Colin; Wieler, Rainer; Rahman, Mustafizur; Bezbaruah, Devojit; Xiaohan, Liu

    2017-08-01

    The Tsangpo-Brahmaputra River drains the eastern part of the Himalayan range and flows from the Tibetan Plateau through the eastern Himalayan syntaxis downstream to the Indo-Gangetic floodplain and the Bay of Bengal. As such, it is a unique natural laboratory to study how denudation and sediment production processes are transferred to river detrital signals. In this study, we present a new 10Be data set to constrain denudation rates across the catchment and to quantify the impact of rapid erosion within the syntaxis region on cosmogenic nuclide budgets and signals. The measured 10Be denudation rates span around 2 orders of magnitude across individual catchments (ranging from 0.03 to > 4 mm yr-1) and sharply increase as the Tsangpo-Brahmaputra flows across the eastern Himalaya. The increase in denudation rates, however, occurs ˜ 150 km downstream of the Namche Barwa-Gyala Peri massif (NBGPm), an area which has been previously characterized by extremely high erosion and exhumation rates. We suggest that this downstream lag is mainly due to the physical abrasion of coarse-grained, low 10Be concentration, landslide material produced within the syntaxis that dilutes the upstream high-concentration 10Be flux from the Tibetan Plateau only after abrasion has transferred sediment to the studied sand fraction. A simple abrasion model produces typical lag distances of 50 to 150 km compatible with our observations. Abrasion effects reduce the spatial resolution over which denudation can be constrained in the eastern Himalayan syntaxis. In addition, we also highlight that denudation rate estimates are dependent on the sediment connectivity, storage, and quartz content of the upstream Tibetan Plateau part of the catchment, which tends to lead to an overestimation of downstream denudation rates. While no direct 10Be denudation measurements were made in the syntaxis, the dilution of the upstream 10Be signal, measured in Tsangpo-Brahmaputra sediments, provides constraints on the

  11. Long-term rates of chemical weathering and physical erosion from cosmogenic nuclides and geochemical mass balance

    NASA Astrophysics Data System (ADS)

    Riebe, Clifford S.; Kirchner, James W.; Finkel, Robert C.

    2003-11-01

    Quantifying long-term rates of chemical weathering and physical erosion is important for understanding the long-term evolution of soils, landscapes, and Earth's climate. Here we describe how long-term chemical weathering rates can be measured for actively eroding landscapes using cosmogenic nuclides together with a geochemical mass balance of weathered soil and parent rock. We tested this approach in the Rio Icacos watershed, Puerto Rico, where independent studies have estimated weathering rates over both short and long timescales. Results from the cosmogenic/mass balance method are consistent with three independent sets of weathering rate estimates, thus confirming that this approach yields realistic measurements of long-term weathering rates. This approach can separately quantify weathering rates from saprolite and from overlying soil as components of the total. At Rio Icacos, nearly 50% of Si weathering occurs as rock is converted to saprolite; in contrast, nearly 100% of Al weathering occurs in the soil. Physical erosion rates are measured as part of our mass balance approach, making it particularly useful for studying interrelationships between chemical weathering and physical erosion. Our data show that chemical weathering rates are tightly coupled with physical erosion rates, such that the relationship between climate and chemical weathering rates may be obscured by site-to-site differences in the rate that minerals are supplied to soil by physical erosion of rock. One can normalize for variations in physical erosion rates using the ;chemical depletion fraction,; which measures the fraction of total denudation that is accounted for by chemical weathering. This measure of chemical weathering intensity increases with increasing average temperature and precipitation in data from climatically diverse granitic sites, including tropical Rio Icacos and six temperate sites in the Sierra Nevada, California. Hence, across a wide range of climate regimes, analysis of

  12. Measurement of natural radioactive nuclide concentrations in various metal ores used as industrial raw materials in Japan and estimation of dose received by workers handling them.

    PubMed

    Iwaoka, Kazuki; Tagami, Keiko; Yonehara, Hidenori

    2009-11-01

    Natural resources such as ores and rocks contain natural radioactive nuclides at various concentrations. If these resources contain high concentrations of natural radioactive nuclides, workers handling them might be exposed to significant levels of radiation. Therefore, it is important to investigate the radioactive activity in these resources. In this study, concentrations of radioactive nuclides in Th, Zr, Ti, Mo, Mn, Al, W, Zn, V, and Cr ores used as industrial raw materials in Japan were investigated. The concentrations of (238)U and (232)Th were determined by inductively coupled plasma mass spectrometry (ICP-MS), while those of (226)Ra, (228)Ra, and (40)K were determined by gamma-ray spectrum. We found the concentrations of (238)U series, (232)Th series, and (40)K in Ti, Mo, Mn, Al, W, Zn, V, and Cr ores to be lower than the critical values defined by regulatory requirements as described in the International Atomic Energy Agency (IAEA) Safety Guide. The doses received by workers handling these materials were estimated by using methods for dose assessment given in a report by the European Commission. In transport, indoor storage, and outdoor storage scenarios, an effective dose due to the use of Th ore was above 4.3 x 10(-2)Sv y(-1), which was higher than that of the other ores. The maximum value of effective doses for other ores was estimated to be about 4.5 x 10(-4)Sv y(-1), which was lower than intervention exemption levels (1.0 x 10(-3)Sv y(-1)) given in International Commission of Radiological Protection (ICRP) Publication 82.

  13. Radioactive nuclides in the incinerator ashes of municipal solid wastes before and after the accident at the Fukushima nuclear power plant.

    PubMed

    Iwahana, Yuki; Ohbuchi, Atsushi; Koike, Yuya; Kitano, Masaru; Nakamura, Toshihiro

    2013-01-01

    Radioactive nuclides in the incinerator ashes of municipal solid wastes were determined by γ-ray spectrometry before and after the accident at the Fukushima nuclear power plant (March 11, 2011). Incinerator ash samples were collected in northern Kyushu, Japan, which is located approximately 1200 km west-southwest (WSW) of the Fukushima nuclear power plant, from April 2006 to March 2007 and from March 2011 to October 2011. (40)K, (137)Cs, (208)Tl, (212)Pb, (214)Pb, (212)Bi, (214)Bi, and (228)Ac were identified in the ashes before the accident (~February 2011) and (134)Cs was identified along with these eight nuclides in the ashes after the accident (March 2011~). A sequential extraction procedure based on a modified Tessier method with added water extraction was used for 1st fly ash sampled in August 2011 because the highest activity concentrations of (134)Cs and (137)Cs were observed for this sample. The speciation of radioactive nuclides in the fly ash was achieved by γ-ray spectrometry and powder X-ray diffractometry for the extraction residues. Little variation was observed in the distribution of the chemical forms of (134)Cs and (137)Cs in 1st fly ash of municipal solid waste; one half of (134)Cs existed as water soluble salts and the other half as carbonate compounds, whereas 75% of (137)Cs existed as water soluble salts with the remainder as carbonates(10%) and sulfides (15%). These results show that 88% of the total radioactive Cs existed in water soluble and ion extractive forms and might be at risk for elution and diffusion with rain and wind.

  14. Heavy-ion radiography and heavy-ion computed tomography

    SciTech Connect

    Fabrikant, J.I.; Holley, W.R.; McFarland, E.W.; Tobias, C.a.

    1982-02-01

    Heavy-ion projection and CT radiography is being developed into a safe, low-dose, noninvasive radiological procedure that can quantitate and image small density differences in human tissues. The applications to heavy-ion mammography and heavy-ion CT imaging of the brain in clinical patients suggest their potential value in cancer diagnosis.

  15. Heavy Flavor Dynamics in Relativistic Heavy-ion Collisions

    NASA Astrophysics Data System (ADS)

    Cao, Shanshan

    Heavy flavor hadrons serve as valuable probes of the transport properties of the quark-gluon plasma (QGP) created in relativistic heavy-ion collisions. In this dissertation, we introduce a comprehensive framework that describes the full-time evolution of heavy flavor in heavy-ion collisions, including its initial production, in-medium evolution inside the QGP matter, hadronization process from heavy quarks to their respective mesonic bound states and the subsequent interactions between heavy mesons and the hadron gas. The in-medium energy loss of heavy quarks is studied within the framework of a Langevin equation coupled to hydrodynamic models that simulate the space-time evolution of the hot and dense QGP matter. We improve the classical Langevin approach such that, apart from quasi-elastic scatterings between heavy quarks and the medium background, radiative energy loss is incorporated as well by treating gluon radiation as a recoil force term. The subsequent hadronization of emitted heavy quarks is simulated via a hybrid fragmentation plus recombination model. The propagation of produced heavy mesons in the hadronic phase is described using the ultra-relativistic quantum molecular dynamics (UrQMD) model. Our calculation shows that while collisional energy loss dominates the heavy quark motion inside the QGP in the low transverse momentum (p T) regime, contributions from gluon radiation are found to be significant at high pT. The recombination mechanism is important for the heavy flavor meson production at intermediate energies. The hadronic final state interactions further enhance the suppression and the collective flow of heavy mesons we observe. Within our newly developed framework, we present numerical results for the nuclear modification and the elliptic flow of D mesons, which are consistent with measurements at both the CERN Large Hadron Collider (LHC) and the BNL Relativistic Heavy-Ion Collider (RHIC); predictions for B mesons are also provided. In

  16. First results using a new technology for measuring masses of very short-lived nuclides with very high accuracy: The MISTRAL program at ISOLDE

    SciTech Connect

    Monsanglant, C.; Audi, G.; Conreur, G.; Cousin, R.; Doubre, H.; Jacotin, M.; Henry, S.; Kepinski, J.-F.; Lunney, D.; Saint Simon, M. de; Thibault, C.; Toader, C.; Bollen, G.; Lebee, G.; Scheidenberger, C.; Borcea, C.; Duma, M.; Kluge, H.-J.; Le Scornet, G.

    1999-11-16

    MISTRAL is an experimental program to measure masses of very short-lived nuclides (T{sub 1/2} down to a few ms), with a very high accuracy (a few 10{sup -7}). There were three data taking periods with radioactive beams and 22 masses of isotopes of Ne, Na, Mg, Al, K, Ca, and Ti were measured. The systematic errors are now under control at the level of 8x10{sup -7}, allowing to come close to the expected accuracy. Even for the very weakly produced {sup 30}Na (1 ion at the detector per proton burst), the final accuracy is 7x10{sup -7}.

  17. Heavy quarks and lattice QCD

    SciTech Connect

    Andreas S. Kronfeld

    2003-11-05

    This paper is a review of heavy quarks in lattice gauge theory, focusing on methodology. It includes a status report on some of the calculations that are relevant to heavy-quark spectroscopy and to flavor physics.

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

    NASA Astrophysics Data System (ADS)

    Schädel, Matthias

    2016-12-01

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

  19. Detecting heavy quarks

    SciTech Connect

    Benenson, G.; Chau, L.L.; Ludlam, T.; Paige, F.E.; Platner, E.D.; Protopopescu, S.D.; Rehak, P.

    1983-01-01

    In this exercise we examine the performance of a detector specifically configured to tag heavy quark (HQ) jets through direct observations of D-meson decays with a high resolution vertex detector. To optimize the performance of such a detector, we assume the small diamond beam crossing configuration as described in the 1978 ISABELLE proposal, giving a luminosity of 10/sup 32/ cm/sup -2/ sec/sup -1/. Because of the very large backgrounds from light quark (LQ) jets, most triggering schemes at this luminosity require high P/sub perpendicular to/ leptons and inevitably give missing neutrinos. If alternative triggering schemes could be found, then one can hope to find and calculate the mass of objects decaying to heavy quarks. A scheme using the high resolution detector will also be discussed in detail. The study was carried out with events generated by the ISAJET Monte Carlo and a computer simulation of the described detector system. (WHK)

  20. Heavy Vehicle Propulsion Materials

    SciTech Connect

    Ray Johnson

    2000-01-31

    The objectives are to Provide Key Enabling Materials Technologies to Increase Energy Efficiency and Reduce Exhaust Emissions. The following goals are listed: Goal 1: By 3rd quarter 2002, complete development of materials enabling the maintenance or improvement of fuel efficiency {ge} 45% of class 7-8 truck engines while meeting the EPA/Justice Department ''Consent Decree'' for emissions reduction. Goal 2: By 4th quarter 2004, complete development of enabling materials for light-duty (class 1-2) diesel truck engines with efficiency over 40%, over a wide range of loads and speeds, while meeting EPA Tier 2 emission regulations. Goal 3: By 4th quarter 2006, complete development of materials solutions to enable heavy-duty diesel engine efficiency of 50% while meeting the emission reduction goals identified in the EPA proposed rule for heavy-duty highway engines.''

  1. Nuclide Importance to Criticality Safety, Decay Heating, and Source Terms Related to Transport and Interim Storage of High-Burnup LWR Fuel

    SciTech Connect

    Gauld, I. C.; Ryman, J. C.

    2000-12-11

    This report investigates trends in the radiological decay properties and changes in relative nuclide importance associated with increasing enrichments and burnup for spent LWR fuel as they affect the areas of criticality safety, thermal analysis (decay heat), and shielding analysis of spent fuel transport and storage casks. To facilitate identifying the changes in the spent fuel compositions that most directly impact these application areas, the dominant nuclides in each area have been identified and ranked by importance. The importance is investigated as a function of increasing burnup to assist in identifying the key changes in spent fuel characteristics between conventional- and extended-burnup regimes. Studies involving both pressurized water-reactor (PWR) fuel assemblies and boiling-water-reactor (BWR) assemblies are included. This study is seen to be a necessary first step in identifying the high-burnup spent fuel characteristics that may adversely affect the accuracy of current computational methods and data, assess the potential impact on previous guidance on isotopic source terms and decay-heat values, and thus help identify areas for methods and data improvement. Finally, several recommendations on the direction of possible future code validation efforts for high-burnup spent fuel predictions are presented.

  2. Work plan for improving the DARWIN2.3 depleted material balance calculation of nuclides of interest for the fuel cycle

    NASA Astrophysics Data System (ADS)

    Rizzo, Axel; Vaglio-Gaudard, Claire; Martin, Julie-Fiona; Noguère, Gilles; Eschbach, Romain

    2017-09-01

    DARWIN2.3 is the reference package used for fuel cycle applications in France. It solves the Boltzmann and Bateman equations in a coupling way, with the European JEFF-3.1.1 nuclear data library, to compute the fuel cycle values of interest. It includes both deterministic transport codes APOLLO2 (for light water reactors) and ERANOS2 (for fast reactors), and the DARWIN/PEPIN2 depletion code, each of them being developed by CEA/DEN with the support of its industrial partners. The DARWIN2.3 package has been experimentally validated for pressurized and boiling water reactors, as well as for sodium fast reactors; this experimental validation relies on the analysis of post-irradiation experiments (PIE). The DARWIN2.3 experimental validation work points out some isotopes for which the depleted concentration calculation can be improved. Some other nuclides have no available experimental validation, and their concentration calculation uncertainty is provided by the propagation of a priori nuclear data uncertainties. This paper describes the work plan of studies initiated this year to improve the accuracy of the DARWIN2.3 depleted material balance calculation concerning some nuclides of interest for the fuel cycle.

  3. A New Approach for the Determination of Dose Rate and Radioactivity for Detected Gamma Nuclides Using an Environmental Radiation Monitor Based on an NaI(Tl) Detector.

    PubMed

    Ji, Young-Yong; Kim, Chang-Jong; Lim, Kyo-Sun; Lee, Wanno; Chang, Hyon-Sock; Chung, Kun Ho

    2017-10-01

    To expand the application of dose rate spectroscopy to the environment, the method using an environmental radiation monitor (ERM) based on a 3' × 3' NaI(Tl) detector was used to perform real-time monitoring of the dose rate and radioactivity for detected gamma nuclides in the ground around an ERM. Full-energy absorption peaks in the energy spectrum for dose rate were first identified to calculate the individual dose rates of Bi, Ac, Tl, and K distributed in the ground through interference correction because of the finite energy resolution of the NaI(Tl) detector used in an ERM. The radioactivity of the four natural radionuclides was then calculated from the in situ calibration factor-that is, the dose rate per unit curie-of the used ERM for the geometry of the ground in infinite half-space, which was theoretically estimated by Monte Carlo simulation. By an intercomparison using a portable HPGe and samples taken from the ground around an ERM, this method to calculate the dose rate and radioactivity of four nuclides using an ERM was experimentally verified and finally applied to remotely monitor them in real-time in the area in which the ERM had been installed.

  4. Applying ISO 11929:2010 Standard to detection limit calculation in least-squares based multi-nuclide gamma-ray spectrum evaluation

    NASA Astrophysics Data System (ADS)

    Kanisch, G.

    2017-05-01

    The concepts of ISO 11929 (2010) are applied to evaluation of radionuclide activities from more complex multi-nuclide gamma-ray spectra. From net peak areas estimated by peak fitting, activities and their standard uncertainties are calculated by weighted linear least-squares method with an additional step, where uncertainties of the design matrix elements are taken into account. A numerical treatment of the standard's uncertainty function, based on ISO 11929 Annex C.5, leads to a procedure for deriving decision threshold and detection limit values. The methods shown allow resolving interferences between radionuclide activities also in case of calculating detection limits where they can improve the latter by including more than one gamma line per radionuclide. The co"mmon single nuclide weighted mean is extended to an interference-corrected (generalized) weighted mean, which, combined with the least-squares method, allows faster detection limit calculations. In addition, a new grouped uncertainty budget was inferred, which for each radionuclide gives uncertainty budgets from seven main variables, such as net count rates, peak efficiencies, gamma emission intensities and others; grouping refers to summation over lists of peaks per radionuclide.

  5. Utah Heavy Oil Program

    SciTech Connect

    J. Bauman; S. Burian; M. Deo; E. Eddings; R. Gani; R. Goel; C.K. Huang; M. Hogue; R. Keiter; L. Li; J. Ruple; T. Ring; P. Rose; M. Skliar; P.J. Smith; J.P. Spinti; P. Tiwari; J. Wilkey; K. Uchitel

    2009-10-20

    The Utah Heavy Oil Program (UHOP) was established in June 2006 to provide multidisciplinary research support to federal and state constituents for addressing the wide-ranging issues surrounding the creation of an industry for unconventional oil production in the United States. Additionally, UHOP was to serve as an on-going source of unbiased information to the nation surrounding technical, economic, legal and environmental aspects of developing heavy oil, oil sands, and oil shale resources. UHOP fulGilled its role by completing three tasks. First, in response to the Energy Policy Act of 2005 Section 369(p), UHOP published an update report to the 1987 technical and economic assessment of domestic heavy oil resources that was prepared by the Interstate Oil and Gas Compact Commission. The UHOP report, entitled 'A Technical, Economic, and Legal Assessment of North American Heavy Oil, Oil Sands, and Oil Shale Resources' was published in electronic and hard copy form in October 2007. Second, UHOP developed of a comprehensive, publicly accessible online repository of unconventional oil resources in North America based on the DSpace software platform. An interactive map was also developed as a source of geospatial information and as a means to interact with the repository from a geospatial setting. All documents uploaded to the repository are fully searchable by author, title, and keywords. Third, UHOP sponsored Give research projects related to unconventional fuels development. Two projects looked at issues associated with oil shale production, including oil shale pyrolysis kinetics, resource heterogeneity, and reservoir simulation. One project evaluated in situ production from Utah oil sands. Another project focused on water availability and produced water treatments. The last project considered commercial oil shale leasing from a policy, environmental, and economic perspective.

  6. Heavy rain field measurements

    NASA Technical Reports Server (NTRS)

    Melson, ED

    1991-01-01

    A weight-measuring rain gauge was developed to collect rain data and configured to operate at a high sample rate (one sample pre second). Instead of averaging the rain rate in minutes, hours, and sometime days as normally performed, the rain data collected are examined in seconds. The results of six field sites are compiled. Rain rate levels, duration of downpours, and frequency of heavy rainfall events are presented.

  7. Retrofitting heavy oil processes

    SciTech Connect

    Hamilton, G.L.; Fitzgerald, M.; D'Amico, V.

    1986-01-01

    Refiners, faced with the need to process the bottom end of the heavy high sulfur crude oil barrel in today's uncertain economic environment, are reluctant to commit large amounts of money to expensive upgrading processes. In order to conserve scarce capital while improving operating margins, additional valuable products can be produced by retrofits such as conversion of an idle crude unit to visbreaking, delayed coking or deasphalting service, or conversion of hydrodesulfurizers to mild hydrocracking.

  8. Hadroduction of heavy flavors

    SciTech Connect

    Leedom, I.D.

    1986-04-01

    The current state of knowledge of heavy quark production, particularly charm, by hadron beams is reviewed. The state of knowledge of total cross section, p/sub T/ and x/sub F/ dependence of charm hadroproduction is given. Besides D production, production of D* is discussed. Also covered is the present evidence for hadronically produced B mesons. 28 refs., 5 figs., 3 tabs. (LEW)

  9. INC Model interpretation of the proton induced residual nuclide production cross sections below 2 GeV

    SciTech Connect

    Divadeenam, M.; Ward, T.E.; Spergel, M.S.; Lakatos, S.; Manche, E.P.

    1991-12-31

    For the purposes of interpreting the abundances of various isotopes in meteorites or on lunar and planetary surfaces exposed to fragmentation by cosmic rays, Webber et al. recently reported the measured total elemental and isotopic cross sections with heavy ions as projectiles on H, He, and C targets with beam energies of 0.33 - 1.7 GeV/nucleon. We employ the INC model to predict the fragmentation of the heavy ions in a hydrogen target with the inverse reaction process: proton bombardment of a heavy-ion nucleus leading to spallation products. Charge-changing and mass-changing cross sections are calculated for proton bombardment of an {sup 56}Fe target with beam energies ranging from 0.33 to 1.88 GeV. Total Z-changing and A-changing cross sections in the energy range 0.6 to 1.88 GeV are in excellent agreement with the corresponding experimental data of Webber et al. and Westfall at al., while the agreement below 0.6 GeV proton energy is not as good. The general trend of the Z-changing cross sections are reproduced by the model calculations at each proton incident energy. The interaction of 200-MeV protons with synthetic Stony Meteorite samples was undertaken to explain radionuclide production in a cosmic-ray environment. The BNL Linac 200-MeV-proton beam was used to irradiate synthetic Stony Meteorites to simulate cosmic-ray exposures corresponding to 6.4 and 16.4 million years. Each irradiated sample was analyzed with the help of a high-resolution gamma-ray spectrometer for long-lived radioisotopes. The intranuclear cascade code HETC was employed to simulate the 200-MeV proton bombardment on the meteorite samples to predict the radionuclides {sup 7}Be, {sup 22}Na, {sup 46}Mn, and {sup 56}Co produced in the experimental investigation.

  10. INC Model interpretation of the proton induced residual nuclide production cross sections below 2 GeV

    SciTech Connect

    Divadeenam, M.; Ward, T.E. ); Spergel, M.S.; Lakatos, S.; Manche, E.P. )

    1991-01-01

    For the purposes of interpreting the abundances of various isotopes in meteorites or on lunar and planetary surfaces exposed to fragmentation by cosmic rays, Webber et al. recently reported the measured total elemental and isotopic cross sections with heavy ions as projectiles on H, He, and C targets with beam energies of 0.33 - 1.7 GeV/nucleon. We employ the INC model to predict the fragmentation of the heavy ions in a hydrogen target with the inverse reaction process: proton bombardment of a heavy-ion nucleus leading to spallation products. Charge-changing and mass-changing cross sections are calculated for proton bombardment of an {sup 56}Fe target with beam energies ranging from 0.33 to 1.88 GeV. Total Z-changing and A-changing cross sections in the energy range 0.6 to 1.88 GeV are in excellent agreement with the corresponding experimental data of Webber et al. and Westfall at al., while the agreement below 0.6 GeV proton energy is not as good. The general trend of the Z-changing cross sections are reproduced by the model calculations at each proton incident energy. The interaction of 200-MeV protons with synthetic Stony Meteorite samples was undertaken to explain radionuclide production in a cosmic-ray environment. The BNL Linac 200-MeV-proton beam was used to irradiate synthetic Stony Meteorites to simulate cosmic-ray exposures corresponding to 6.4 and 16.4 million years. Each irradiated sample was analyzed with the help of a high-resolution gamma-ray spectrometer for long-lived radioisotopes. The intranuclear cascade code HETC was employed to simulate the 200-MeV proton bombardment on the meteorite samples to predict the radionuclides {sup 7}Be, {sup 22}Na, {sup 46}Mn, and {sup 56}Co produced in the experimental investigation.

  11. Cross section systematics for the lightest Bi and Po nuclei produced in complete fusion reactions with heavy ions

    SciTech Connect

    Andreyev, A.N.; Ackermann, D.; Muenzenberg, G.; Antalic, S.; Saro, S.; Streicher, B.; Darby, I.G.; Page, R.D.; Wiseman, D.R.; Franchoo, S.; Hessberger, F.P.; Kuusiniemi, P.; Lommel, B.; Kindler, B.; Mann, R.; Sulignano, B.; Hofmann, S.; Huyse, M.; Vel, K. van de; Duppen, P. van

    2005-07-01

    The production of the very neutron-deficient nuclides {sup 184-192}Bi and {sup 186-192}Po in the vicinity of the neutron midshell at N = 104 has been studied by using heavy-ion-induced complete fusion reactions in a series of experiments at the velocity filter SHIP. The cross sections for the xn and pxn evaporation channels of the {sup 46}Ti+{sup 144}Sm{yields}{sup 190}Po*,{sup 98}Mo+{sup 92}Mo{yields}{sup 190}Po*,{sup 50,52}Cr+{sup 142}Nd{yields}{sup 192,194}Po*, and {sup 94,95}Mo+{sup 93}Nb{yields}{sup 187,188}Bi* reactions were measured. The results obtained, together with the previously known cross section data for the heavier Bi and Po nuclides, are compared with the results of statistical model calculations carried out with the HIVAP code. It is shown that a satisfactory description of the experimental data requires a significant (up to 35%) reduction of the theoretical fission barriers. The optimal reactions for production of the lightest Bi and Po isotopes are discussed.

  12. Heavy Stars Thrive among Heavy Elements

    NASA Astrophysics Data System (ADS)

    2002-08-01

    VLT Observes Wolf-Rayet Stars in Virgo Cluster Galaxies [1] Summary Do very massive stars form in metal-rich regions of the Universe and in the nuclei of galaxies ? Or does "heavy element poisoning" stop stellar growth at an early stage, before young stars reach the "heavyweight class"? What may at the first glance appear as a question for specialists actually has profound implications for our understanding of the evolution of galaxies, those systems of billions of stars - the main building blocks of the Universe. With an enormous output of electromagnetic radiation and energetic elementary particles, massive stars exert a decisive influence on the surrounding (interstellar) gas and dust clouds . They also eject large amounts of processed elements, thereby participating in the gradual build-up of the many elements we see today. Thus the presence or absence of such stars at the centres of galaxies can significantly change the overall development of those regions and hence, presumably, that of the entire galaxy. A team of European astronomers [2] has now directly observed the presence of so-called Wolf-Rayet stars (born with masses of 60 - 90 times that of the Sun or more) within metal-rich regions in some galaxies in the Virgo cluster, some 50 million light-years away. This is the first unambiguous detection of such massive stellar objects in metal-rich regions . PR Photo 20a/02 : H II regions in the Virgo cluster galaxy NGC 4254 . PR Photo 20b/02 : Multi-object-slit observation of galaxy NGC 4303 . PR Photo 20c/02 : Spectrum of H II region in NGC 4254 with Wolf-Rayet signatures. Production of heavy elements in the Universe Most scientists agree that the Universe in which we live underwent a dramatic event, known as the Big Bang , approximately 15,000 million years ago. During the early moments, elementary particles were formed which after some time united into more complex nuclei and in turn resulted in the production of hydrogen and helium atoms and their isotopes

  13. Heavy-heavy and heavy-light quarks interactions generated by QCD vacuum

    NASA Astrophysics Data System (ADS)

    Musakhanov, Mirzayusuf

    2017-03-01

    The QCD vacuum is populated by instantons that correspond to the tunneling processes in the vacuum. This mechanism creates the strong vacuum gluon fields. As result, the QCD vacuum instantons induce very strong interactions between light quarks, initially almost massless. Such a strong interactions bring a large dynamical mass M of the light quarks and bound them to produce almost massless pions in accordance with the spontaneous breaking of the chiral symmetry (SBCS). On the other hand, the QCD vacuum instantons also interact with heavy quarks and responsible for the generation of the heavy-heavy and heavy-light quarks interactions, with a traces of the SBCS. If we take the average instanton size \\bar ρ = 0.33 fm, and the average inter-instanton distance \\bar R = 1 fm we obtain the dynamical light quark mass to be M = 365 MeV and the instanton media contribution to the heavy quark mass ΔM=70 MeV. These factors define the coupling between heavy-light and heavy-heavy quarks induced by the QCD vacuum instantons. We consider first the instanton effects on the heavy-heavy quarks potential, including its spin-dependent part. We also discuss those effects on the masses of the charmonia and their hyperfine mass splittings. At the second part we discuss the interaction between a heavy and light quarks generated by instantons and it's effects.

  14. Cosmogenic Nuclides 10Be-21Ne Burial Dating of Middle Miocene Sedimentary Formation of the Hongliu Valley in Southern Ningxia Basin: A Case of Isotopic Geochronology Study for the Cenozoic Sedimentary Strata

    NASA Astrophysics Data System (ADS)

    Ma, Yan; Zhang, Huiping; Wang, Weitao; Pang, Jianzhang; Zheng, Dewen

    2016-04-01

    Chronology studies for the Cenozoic sedimentary strata based on the magnetostratigraphy cannot afford the unique chronological sequences in the absence of absolute ages from biostratigraphy or volcanic ash chronology. In situ-produced cosmogenic nuclides provide a powerful tool for the sediment dating based on the time-dependent concentration ratio of two nuclides, which are produced in the same mineral but with different half-lives. Thereinto,10Be-26Al is the most widely used nuclide pairs, of which the available dating range spans the Plio-Pleistocene. But the coupling of 10Be with the stable nuclide 21Ne would significantly improve the burial dating range up to the middle Miocene, which is promising in revolutionizing the chronology study for the Late Cenozoic terrestrial sedimentary sequences. We have applied 10Be-21Ne pair for dating the middle Miocene sediments of the Hongliu Valley in southern Ningxia basin. Two major features of the sediments are involved in our study: (1) sediments originated from the steady erosion of the source area, and (2) the burial depth of our sample after deposition is time dependent due to the gradual accumulation of sediments into basin. The post-burial nuclide production is estimated to be less than 3%, including the contribution by muon interactions, of the total nuclide concentrations measured in our sample. Our 10Be-21Ne analysis demonstrates the age of the burial sample is 12.4(+0.6/-0.4) Ma, and the erosion rate at the source area is 0.26±0.01 cm ka-1. The sample's burial age is consistent with the age constraint set by the Hongliugou Formation (16.7-5.4 Ma) which we collected the sample in. Vertebrate fossils of Platybelodon tongxinensis with an age between 12 and 15 Ma exhumated along with our sample further verifies the reliability of our dating results for the middle Miocene sediments.This study has shown the improved age range of cosmogenic-nuclide burial dating method by incorporating the stable nuclide 21Ne, and has

  15. Heavy Truck Engine Program

    SciTech Connect

    Nelson, Christopher

    2009-01-08

    The Heavy Duty Truck Engine Program at Cummins embodied three significant development phases. All phases of work strove to demonstrate a high level of diesel engine efficiency in the face of increasingly stringent emission requirements. Concurrently, aftertreatment system development and refinement was pursued in support of these efficiency demonstrations. The program's first phase focused on the demonstration in-vehicle of a high level of heavy duty diesel engine efficiency (45% Brake Thermal Efficiency) at a typical cruise condition while achieving composite emissions results which met the 2004 U.S. EPA legislated standards. With a combination of engine combustion calibration tuning and the development and application of Urea-based SCR and particulate aftertreatment, these demonstrations were successfully performed by Q4 of 2002. The second phase of the program directed efforts towards an in-vehicle demonstration of an engine system capable of meeting 2007 U.S. EPA legislated emissions requirements while achieving 45% Brake Thermal Efficiency at cruise conditions. Through further combustion optimization, the refinement of Cummins Cooled EGR architecture, the application of a high pressure common rail fuel system and the incorporation of optimized engine parasitics, Cummins Inc. successfully demonstrated these deliverables in Q2 of 2004. The program's final phase set a stretch goal of demonstrating 50% Brake Thermal Efficiency from a heavy duty diesel engine system capable of meeting 2010 U.S. EPA legislated emissions requirements. Cummins chose to pursue this goal through further combustion development and refinement of the Cooled EGR system architecture and also applied a Rankine cycle Waste Heat Recovery technique to convert otherwise wasted thermal energy to useful power. The engine and heat recovery system was demonstrated to achieve 50% Brake Thermal Efficiency while operating at a torque peak condition in second quarter, 2006. The 50% efficient engine

  16. Heavy Metal Factory

    NASA Astrophysics Data System (ADS)

    Löbling, Lisa

    2017-07-01

    The metal enrichment in the cosmic circuit of matter is dominated by the yields of asymptotic giant branch (AGB) nucleosynthesis, that are blown back into the interstellar medium just before these stars die as white dwarfs. To establish constraints on AGB processes, spectral analyses of hot post-AGB stars are mandatory. These show that such stars are heavy metal factories due to the AGB s-process. The Virtual Observatory service TheoSSA offers access to synthetic stellar spectra calculated with our Tübingen non-local thermodynamic equilibrium model-atmosphere package that are suitable for the analysis of hot post-AGB stars.

  17. Heavy fermion superconductivity

    NASA Astrophysics Data System (ADS)

    Brison, Jean-Pascal; Glémot, Loı̈c; Suderow, Hermann; Huxley, Andrew; Kambe, Shinsaku; Flouquet, Jacques

    2000-05-01

    The quest for a precise identification of the symmetry of the order parameter in heavy fermion systems has really started with the discovery of the complex superconducting phase diagram in UPt 3. About 10 years latter, despite numerous experiments and theoretical efforts, this is still not achieved, and we will quickly review the present status of knowledge and the main open question. Actually, the more forsaken issue of the nature of the pairing mechanism has been recently tackled by different groups with macroscopic or microscopic measurement, and significant progress have been obtained. We will discuss the results emerging from these recent studies which all support non-phonon-mediated mechanisms.

  18. Heavy ion storage rings

    SciTech Connect

    Schuch, R.

    1987-01-01

    A brief overview of synchrotron storage rings for heavy ions, which are presently under construction in different accelerator laboratories is given. Ions ranging from protons up to uranium ions at MeV/nucleon energies will be injected into these rings using multiturn injection from the accelerators available or being built in these laboratories. After injection, it is planned to cool the phase space distribution of the ions by merging them with cold electron beams or laser beams, or by using stochastic cooling. Some atomic physics experiments planned for these rings are presented.

  19. Heavy-antiquark-diquark symmetry and heavy hadron molecules: Are there triply heavy pentaquarks?

    NASA Astrophysics Data System (ADS)

    Guo, Feng-Kun; Hidalgo-Duque, Carlos; Nieves, Juan; Valderrama, Manuel Pavón

    2013-09-01

    We explore the consequences of heavy flavor, heavy quark spin, and heavy antiquark-diquark symmetries for hadronic molecules within an effective field theory framework. Owing to heavy antiquark-diquark symmetry, the doubly heavy baryons have approximately the same light-quark structure as the heavy antimesons. As a consequence, the existence of a heavy meson-antimeson molecule implies the possibility of a partner composed of a heavy meson and a doubly heavy baryon. In this regard, the DD¯* molecular nature of the X(3872) will hint at the existence of several baryonic partners with isospin I=0 and JP=(5)/(2)(-)/() or (3)/(2)(-)/(). Moreover, if the Zb(10650) turns out to be a B*B¯* bound state, we can be confident of the existence of Ξbb*B¯* hadronic molecules with quantum numbers I(JP)=1((1)/(2)(-)/()) and I(JP)=1((3)/(2)(-)/()). These states are of special interest since they can be considered to be triply heavy pentaquarks.

  20. Heavy ion therapy: Bevalac epoch

    SciTech Connect

    Castro, J.R.

    1993-10-01

    An overview of heavy ion therapy at the Bevelac complex (SuperHILac linear accelerator + Bevatron) is given. Treatment planning, clinical results with helium ions on the skull base and uveal melanoma, clinical results with high-LET charged particles, neon radiotherapy of prostate cancer, heavy charged particle irradiation for unfavorable soft tissue sarcoma, preliminary results in heavy charged particle irradiation of bone sarcoma, and irradiation of bile duct carcinoma with charged particles and-or photons are all covered. (GHH)

  1. Heavy quark production and spectroscopy

    SciTech Connect

    Appel, J.A.

    1993-11-01

    This review covers many new experimental results on heavy flavor production and spectroscopy. It also shows some of the increasingly improved theoretical understanding of results in light of basic perturbative QCD and heavy quark symmetry. At the same time, there are some remaining discrepancies among experiments as well as significant missing information on some of the anticipated lowest lying heavy quark states. Most interesting, perhaps, are some clearly measured production effects awaiting full explanation.

  2. Heavy-flavor production overview

    SciTech Connect

    Jeffrey A. Appel

    2003-12-10

    This talk serves as an introduction to the Heavy-Flavor session of the XXXIII International Symposium on Multiparticle Dynamics. A major focus of this session is on the production of heavy quarks. The talks which follow review the latest results on heavy quark production in strong, electromagnetic, and weak interactions, as well as some of the physics of the heavy quarks themselves. This talk emphasizes what we can learn from the production measurements, both about underlying QCD theory and the partonic nature of the hadrons which we see in the laboratory.

  3. Interference between light and heavy neutrinos for 0νββ decay in the left–right symmetric model

    DOE PAGES

    Ahmed, Fahim; Neacsu, Andrei; Horoi, Mihai

    2017-03-31

    Neutrinoless double-beta decay is proposed as an important low energy phenomenon that could test beyond the Standard Model physics. There are several potentially competing beyond the Standard Model mechanisms that can induce the process. It thus becomes important to disentangle the different processes. In the present study we consider the interference effect between the light left-handed and heavy right-handed Majorana neutrino exchange mechanisms. The decay rate, and consequently, the phase-space factors for the interference term are derived, based on the left–right symmetric model. The numerical values for the interference phase-space factors for several nuclides are calculated, taking into consideration themore » relativistic Coulomb distortion of the electron wave function and finite-size of the nucleus. As a result, the variation of the interference effect with the Q-value of the process is studied.« less

  4. Interference between light and heavy neutrinos for 0νββ decay in the left-right symmetric model

    NASA Astrophysics Data System (ADS)

    Ahmed, Fahim; Neacsu, Andrei; Horoi, Mihai

    2017-06-01

    Neutrinoless double-beta decay is proposed as an important low energy phenomenon that could test beyond the Standard Model physics. There are several potentially competing beyond the Standard Model mechanisms that can induce the process. It thus becomes important to disentangle the different processes. In the present study we consider the interference effect between the light left-handed and heavy right-handed Majorana neutrino exchange mechanisms. The decay rate, and consequently, the phase-space factors for the interference term are derived, based on the left-right symmetric model. The numerical values for the interference phase-space factors for several nuclides are calculated, taking into consideration the relativistic Coulomb distortion of the electron wave function and finite-size of the nucleus. The variation of the interference effect with the Q-value of the process is studied.

  5. Cross Sections of P-Induced Reactions up to 100 MeV for the Interpretation of Solar Cosmic Ray Produced Nuclides

    NASA Astrophysics Data System (ADS)

    Schiekel, T.; Rosel, R.; Herpers, U.; Bodemann, R.; Michel, R.; Dittrich, B.; Hofmann, H. J.; Suter, M.; Wolfli, W.; Holmqvist, B.; Conde, H.; Malmborg, P.

    1992-07-01

    Integral excitation functions for the production of residual nuclides by proton-induced reactions are the basic data for an accurate modelling of the interactions of solar cosmic ray (SCR) particles with extraterrestrial matter. Due to the relatively low energies (<200 MeV/A) of SCR particles the production of nuclear active secondary particles can be widely neglected and theoretical production rate depth profiles can be calculated by simply folding the depth dependent SCR spectra with thin target cross sections of the underlying nuclear reactions. The accuracy of such calculations exclusively depends on the quality of the available cross sections. For many nuclides, in particular for long-lived radionuclides and stable rare gas isotopes, the exis- ting cross section database is neither comprehensive nor reliable. Therefore, we started a series of experiments to improve this situation. Eighteen elements (C, N as Si3N4, O as SiO2, Mg, Al, Si, Ti, V, Mn as Mn/Ni-alloy, Fe, Co, Ni, Cu, Zr, Nb, Rh, Ba as Ba-contai- ning glass, and Au) were irradiated with 94 and 99 MeV protons at the external beam of the TSL-cyclotron at Uppsala. Cross sections were determined using the stacked foil technique. Beam monitoring was done by investigating the production of ^22Na from Al, for which evaluated cross sections exist. Residual nuclides were measured by X-, gamma- and accelerator-mass spectrometry. In order to check the quality of our experimental procedure some target elements (22 <= Z <= 28) were included in the new exper- iments, which had been formerly irradiated at Julich, at Louvain La Neuve, and at IPN Orsay. Comparisons between the earlier measurements (1,2) and the new cross sections showed excellent agreement. Up to now, cross sections were measured for more than 120 different reactions. Here, we report on the results obtained for the target elements C, N, O, Mg, Al, and Si. The status of experimental excitation functions for the production of some radionuclides

  6. First Results Using a New Technology for Measuring Masses of Very Short-Lived Nuclides with Very High Accuracy: the MISTRAL Program at ISOLDE

    SciTech Connect

    C. Monsanglant; C. Toader; G. Audi; G. Bollen; C. Borcea; G. Conreur; R. Cousin; H. Doubre; M. Duma; M. Jacotin; S. Henry; J.-F. Kepinski; H.-J. Kluge; G. Lebee; G. Le Scornet; D. Lunney; M. de Saint Simon; C. Scheidenberger; C. Thibault

    1999-12-31

    MISTRAL is an experimental program to measure masses of very short-lived nuclides (T{sub 1/2} down to a few ms), with a very high accuracy (a few 10{sup -7}). There were three data taking periods with radioactive beams and 22 masses of isotopes of Ne, Na{clubsuit}, Mg, Al{clubsuit}, K, Ca, and Ti were measured. The systematic errors are now under control at the level of 8x10{sup -7}, allowing to come close to the expected accuracy. Even for the very weakly produced {sup 30}Na (1 ion at the detector per proton burst), the final accuracy is 7x10{sup -7}.

  7. Study of CdMoO4 crystal for a neutrinoless double beta decay experiment with 116Cd and 100Mo nuclides

    NASA Astrophysics Data System (ADS)

    Xue, Ming-Xuan; Zhang, Yun-Long; Peng, Hai-Ping; Xu, Zi-Zong; Wang, Xiao-Lian

    2017-04-01

    The scintillation properties of a CdMoO4 crystal have been investigated experimentally. The fluorescence yields and decay times measured from 22 K to 300 K demonstrate that CdMoO4 crystal is a good candidate for an absorber for a bolometer readout, for both heat and scintillation signals. The results from Monte Carlo studies, taking the backgrounds from 2ν2β of and internal trace nuclides 214Bi and 208Tl into account, show that the expected sensitivity of a CdMoO4 bolometer for neutrinoless double beta decay experiments with an exposure of 100 kg·years is one order of magnitude higher than those of the current sets of the of and Supported by National Natural Science Foundation of China (11275199)

  8. The deep accumulation of 10Be at Utsira, southwestern Norway: Implications for cosmogenic nuclide exposure dating in peripheral ice sheet landscapes

    NASA Astrophysics Data System (ADS)

    Briner, Jason P.; Goehring, Brent M.; Mangerud, Jan; Svendsen, John Inge

    2016-09-01

    Cosmogenic nuclide exposure dating is a widely used method for constraining past ice sheet histories. We scrutinize a recently published data set of cosmogenic 10Be data from erratic boulders in Norway used to constrain the deglaciation of the western Scandinavian Ice Sheet to 20 ka. Our model of the 10Be inventory in glacial surfaces leads us to conclude that the chronology may be afflicted by the deep subsurface accumulation of 10Be during long-lasting ice-free periods that resulted in 10Be ages >10% too old. We suggest that the majority of the dated erratic boulders contain a uniform level of inherited muon-produced 10Be and were derived from bedrock depths >2.5 m and most likely ~4 m. The implication of our finding is that for landscapes that experience long ice-free periods between brief maximum glacial phases, glacial erosion of >5 m is required to remove detectable traces of inherited 10Be.

  9. Propagation of heavy baryons in heavy-ion collisions

    NASA Astrophysics Data System (ADS)

    Das, Santosh K.; Torres-Rincon, Juan M.; Tolos, Laura; Minissale, Vincenzo; Scardina, Francesco; Greco, Vincenzo

    2016-12-01

    The drag and diffusion coefficients of heavy baryons (Λc and Λb ) in the hadronic phase created in the latter stage of the heavy-ion collisions at RHIC and LHC energies have been evaluated recently. In this work we compute some experimental observables, such as the nuclear suppression factor RA A and the elliptic flow v2 of heavy baryons at RHIC and LHC energies, highlighting the role of the hadronic phase contribution to these observables, which are going to be measured at Run 3 of LHC. For the time evolution of the heavy quarks in the quark and gluon plasma (QGP) and heavy baryons in the hadronic phase, we use the Langevin dynamics. For the hadronization of the heavy quarks to heavy baryons we employ Peterson fragmentation functions. We observe a strong suppression of both the Λc and Λb . We find that the hadronic medium has a sizable impact on the heavy-baryon elliptic flow whereas the impact of hadronic medium rescattering is almost unnoticeable on the nuclear suppression factor. We evaluate the Λc/D ratio at RHIC and LHC. We find that the Λc/D ratio remains unaffected due to the hadronic phase rescattering which enables it as a nobel probe of QGP phase dynamics along with its hadronization.

  10. Rheological properties of heavy oils and heavy oil emulsions

    SciTech Connect

    Khan, M.R.

    1996-06-01

    In this study, the author investigated the effects of a number of process variables such as shear rate, measurement temperature, pressure, the influence of pretreatment, and the role of various amounts of added water on the rheology of the resulting heavy oil or the emulsion. Rheological properties of heavy oils and the corresponding emulsions are important from transportation and processing standpoints.

  11. Decay of heavy particles from Z = 125 superheavy nuclei in the region A = 295-325 using different versions of proximity potential

    NASA Astrophysics Data System (ADS)

    Santhosh, K. P.; Sukumaran, Indu

    Within the framework of Coulomb and proximity potential model (CPPM), the probable heavy particle decays from various isotopes of superheavy nuclei (SHN), Z = 125, within the range A = 295-325 have been studied using two versions of proximity potential; proximity 1977 and proximity 2000. The decay half lives evaluated using proximity 2000 is observed to be higher than the values obtained using proximity 1977. The effect of surface deformation on the decay half lives is studied using Coulomb and proximity potential for deformed nuclei (CPPMDN). As a result of the inclusion of deformation (β2), the penetrability of the decays are observed to be increased and accordingly the decay half lives are reduced. The estimated values are compared with other theoretical models, Universal curve (UNIV), Universal Decay law (UDL) and the scaling law of Horoi. The odd-even staggering (OES) effect is observed in the emission of odd mass clusters. An intriguing aspect of the study is the effect of the magicity at N = 184 which is confirmed from the plot of log10T1/2 against the neutron number of the daughter nuclei. Almost all the predicted half lives are favorable for experimental measurements. The Geiger-Nuttall (GN) plots and the Universal curve have been studied for various cluster emissions from various superheavy isotopes with Z = 125. Finally, the linearity of the GN plot and the Universal curve of the heavy particle emissions very well established the strength of CPPM.

  12. Erosion rate study at the Allchar deposit (Macedonia) based on radioactive and stable cosmogenic nuclides (26 Al, 36 Cl, 3 He, and 21 Ne)

    PubMed Central

    Cvetković, V.; Niedermann, S.; Pejović, V.; Amthauer, G.; Boev, B.; Bosch, F.; Aničin, I.; Henning, W. F.

    2016-01-01

    Abstract This paper focuses on constraining the erosion rate in the area of the Allchar Sb‐As‐Tl‐Au deposit (Macedonia). It contains the largest known reserves of lorandite (TlAsS2), which is essential for the LORanditeEXperiment (LOREX), aimed at determining the long‐term solar neutrino flux. Because the erosion history of the Allchar area is crucial for the success of LOREX, we applied terrestrial in situ cosmogenic nuclides including both radioactive (26Al and 36Cl) and stable (3He and 21Ne) nuclides in quartz, dolomite/calcite, sanidine, and diopside. The obtained results suggest that there is accordance in the values obtained by applying 26Al, 36Cl, and 21Ne for around 85% of the entire sample collection, with resulting erosion rates varying from several tens of m/Ma to ∼165 m/Ma. The samples from four locations (L‐8 CD, L1b/R, L1c/R, and L‐4/ADR) give erosion rates between 300 and 400 m/Ma. Although these localities reveal remarkably higher values, which may be explained by burial events that occurred in part of Allchar, the erosion rate estimates mostly in the range between 50 and 100 m/Ma. This range further enables us to estimate the vertical erosion rate values for the two main ore bodies Crven Dol and Centralni Deo. We also estimate that the lower and upper limits of average paleo‐depths for the ore body Centralni Deo from 4.3 Ma to the present are 250–290 and 750–790 m, respectively, whereas the upper limit of paleo‐depth for the ore body Crven Dol over the same geological age is 860 m. The estimated paleo‐depth values allow estimating the relative contributions of 205Pb derived from pp‐neutrino and fast cosmic‐ray muons, respectively, which is an important prerequisite for the LOREX experiment. PMID:27587984

  13. Active faulting, mountain growth, and erosion at the margins of the Tibetan Plateau constrained by in situ-produced cosmogenic nuclides

    NASA Astrophysics Data System (ADS)

    Hetzel, Ralf

    2013-01-01

    The India-Asia collision zone is a key area for understanding continental plateau formation and mountain building. Two fundamental questions in this context are how the northeastward motion of India is partitioned between strike-slip and thrust faults and how mountain building is counteracted by erosion. Cosmogenic nuclides allow us to address these questions, because they provide age constraints on tectonically offset landforms and constraints on erosion rates. After considerable debate on whether or not major strike-slip faults move at high rates of up to 20-30 mm/yr and absorb most of the continental deformation, it now appears that the three largest faults (Altyn Tagh, Haiyuan, Kunlun) have millennial slip rates of no more than 8-13 mm/yr, consistent with rates of elastic strain accumulation determined by geodetic methods. Furthermore, a significant portion of the lateral slip on these faults is transferred to thrust faults within the collision zone. Both observations indicate that the eastward tectonic escape of material along these faults is less important than often assumed. With respect to mountain building and erosion, cosmogenic nuclide studies show that thrust faults at the northeastern and eastern margins of Tibet (Qilian Shan, Longmen Shan) have vertical slip rates of ~ 0.3 to ~ 2 mm/yr while catchment-wide erosion rates vary from ~ 0.02 to ~ 1.0 mm/yr, with high-relief areas eroding significantly faster than the plateau interior and growing mountains in the foreland. The deeply incised regions have apparently reached an erosional steady-state, in which rock uplift is balanced by erosion. River terraces at active mountain fronts document repeated changes between sediment deposition and fluvial incision. During the Quaternary, incision and terrace formation occurred predominantly at glacial-interglacial transitions but also during interglacial periods. Hence, flights of terraces at the fault-bounded mountain fronts record the interplay between sustained

  14. Erosion rate study at the Allchar deposit (Macedonia) based on radioactive and stable cosmogenic nuclides ((26)Al, (36)Cl, (3)He, and (21)Ne).

    PubMed

    Pavićević, M K; Cvetković, V; Niedermann, S; Pejović, V; Amthauer, G; Boev, B; Bosch, F; Aničin, I; Henning, W F

    2016-02-01

    This paper focuses on constraining the erosion rate in the area of the Allchar Sb-As-Tl-Au deposit (Macedonia). It contains the largest known reserves of lorandite (TlAsS2), which is essential for the LORanditeEXperiment (LOREX), aimed at determining the long-term solar neutrino flux. Because the erosion history of the Allchar area is crucial for the success of LOREX, we applied terrestrial in situ cosmogenic nuclides including both radioactive ((26)Al and (36)Cl) and stable ((3)He and (21)Ne) nuclides in quartz, dolomite/calcite, sanidine, and diopside. The obtained results suggest that there is accordance in the values obtained by applying (26)Al, (36)Cl, and (21)Ne for around 85% of the entire sample collection, with resulting erosion rates varying from several tens of m/Ma to ∼165 m/Ma. The samples from four locations (L-8 CD, L1b/R, L1c/R, and L-4/ADR) give erosion rates between 300 and 400 m/Ma. Although these localities reveal remarkably higher values, which may be explained by burial events that occurred in part of Allchar, the erosion rate estimates mostly in the range between 50 and 100 m/Ma. This range further enables us to estimate the vertical erosion rate values for the two main ore bodies Crven Dol and Centralni Deo. We also estimate that the lower and upper limits of average paleo-depths for the ore body Centralni Deo from 4.3 Ma to the present are 250-290 and 750-790 m, respectively, whereas the upper limit of paleo-depth for the ore body Crven Dol over the same geological age is 860 m. The estimated paleo-depth values allow estimating the relative contributions of (205)Pb derived from pp-neutrino and fast cosmic-ray muons, respectively, which is an important prerequisite for the LOREX experiment.

  15. Erosion rate study at the Allchar deposit (Macedonia) based on radioactive and stable cosmogenic nuclides (26Al, 36Cl, 3He, and 21Ne)

    NASA Astrophysics Data System (ADS)

    Pavićević, M. K.; Cvetković, V.; Niedermann, S.; Pejović, V.; Amthauer, G.; Boev, B.; Bosch, F.; Aničin, I.; Henning, W. F.

    2016-02-01

    This paper focuses on constraining the erosion rate in the area of the Allchar Sb-As-Tl-Au deposit (Macedonia). It contains the largest known reserves of lorandite (TlAsS2), which is essential for the LORanditeEXperiment (LOREX), aimed at determining the long-term solar neutrino flux. Because the erosion history of the Allchar area is crucial for the success of LOREX, we applied terrestrial in situ cosmogenic nuclides including both radioactive (26Al and 36Cl) and stable (3He and 21Ne) nuclides in quartz, dolomite/calcite, sanidine, and diopside. The obtained results suggest that there is accordance in the values obtained by applying 26Al, 36Cl, and 21Ne for around 85% of the entire sample collection, with resulting erosion rates varying from several tens of m/Ma to ˜165 m/Ma. The samples from four locations (L-8 CD, L1b/R, L1c/R, and L-4/ADR) give erosion rates between 300 and 400 m/Ma. Although these localities reveal remarkably higher values, which may be explained by burial events that occurred in part of Allchar, the erosion rate estimates mostly in the range between 50 and 100 m/Ma. This range further enables us to estimate the vertical erosion rate values for the two main ore bodies Crven Dol and Centralni Deo. We also estimate that the lower and upper limits of average paleo-depths for the ore body Centralni Deo from 4.3 Ma to the present are 250-290 and 750-790 m, respectively, whereas the upper limit of paleo-depth for the ore body Crven Dol over the same geological age is 860 m. The estimated paleo-depth values allow estimating the relative contributions of 205Pb derived from pp-neutrino and fast cosmic-ray muons, respectively, which is an important prerequisite for the LOREX experiment.

  16. Origin, structure and exposure history of a wave-cut platform more than 1 Ma in age at the coast of northern Spain: A multiple cosmogenic nuclide approach

    NASA Astrophysics Data System (ADS)

    Alvarez-Marrón, J.; Hetzel, R.; Niedermann, S.; Menéndez, R.; Marquínez, J.

    2008-01-01

    Along the Asturian coast of northern Spain an uplifted wave-cut platform extends for ˜ 100 km east-west. The steep cliff which bounds the gently seaward-dipping platform to the north increases in height from 30 m in the west to 100 m in the east and reflects the overall eastward increase in platform elevation. The southern edge of the 2-4 km-wide platform runs along the foothills of the Cantabrian Mountains, as constrained by a high-resolution digital elevation model. The marine platform, which was carved into deformed Paleozoic bedrock with abundant quartzite beds, is largely covered by weathered marine and continental sediments. Quartzite samples from flat bedrock outcrops which are currently not covered by sediment or soil yield cosmogenic nuclide concentrations ( 21Ne, 10Be and 26Al) that demonstrate a long and complex exposure history, including periods of burial with partial or complete shielding from cosmic rays. The combination of multiple cosmogenic nuclides yields a minimum age of 1-2 Ma for the platform. Taking into account (i) the horizontal and vertical extent of the platform, (ii) the high resistance to erosion of the quartzitic bedrock, and (iii) published data on the magnitude of past sea level fluctuations, we suggest that the wave-cut platform formed in the Pliocene. Subvertical faults cutting the platform at high angles to the coastline offset the southern edge of the platform by 20 to 40 m and reactivate the pre-existing anisotropy in the Paleozoic bedrock. Uplift and crustal deformation of the coastal region have occurred after platform formation in the Pliocene and may still be active. The slow deformation of the northern edge of the Iberian plate including the Cantabrian Mountains may result from the ongoing slow convergence at an incipient subduction zone extending along the coast of northern Spain.

  17. Geological Context of Cosmogenic-Nuclide Sampling Sites for the CRONUS-Earth Project on the Shoreline of Paleo-Lake Bonneville, Utah

    NASA Astrophysics Data System (ADS)

    Phillips, F. M.

    2005-12-01

    One of the objectives of the NSF-funded CRONUS-Earth Project is to obtain geologically and geochronologically well-constrained samples in which the production rates of a large number of cosmogenic nuclides can be compared. One area sampled for this purpose, in July 2005, was associated with the shoreline of Lake Bonneville, a very large Pleistocene pluvial lake that occupied the current Great Salt Lake basin. The Bonneville highstand represented the all-time high lake level in the basin. The timing of this event is well constrained by 14C dating. The lake approached the Bonneville highstand by ~18.9 ka. The highstand probably lasted ~1.7 ka and ended at 17.4±0.2 ka by downcutting of the lake sill at Red Rock Pass. We sampled two localities associated with the shoreline: Tabernacle Hill and Promontory Point. The Tabernacle Hill basalt flow was erupted during the Bonneville highstand and was partially covered by the lake. We sampled the flow at seven locations approximately 500 m south of the northeast margin of the flow. The location of the Bonneville shoreline, marked by wave erosion and tufa deposition, was verified to be to the northeast of, and below, the sampling sites. Samples were collected from the tops of push-up ridges using a rock saw. Promontory Point was sampled from a pronounced wave-cut bench on the west side. At the sample site, the depth of wave erosion was ~140 m. The bench was cut into quartzite. Samples were collected by rock saw and hammer and chisel from wave-planed bedrock outcrops. Based on geological mapping, the sample sites were 18 to 27 m below the lake surface elevation (depending on sample location), with an estimated uncertainty of ±5 m. The geometry of the pre-Bonneville topography can be reconstructed with a fair degree of confidence, enabling correction of the measured nuclide concentrations for pre-Bonneville production by muons.

  18. Effects of Climate on Long-term Rates of Physical Erosion and Chemical Weathering: Evidence from Cosmogenic Nuclides and Geochemical Mass Balance

    NASA Astrophysics Data System (ADS)

    Kirchner, J. W.; Riebe, C. S.; Ferrier, K. L.; Finkel, R. C.

    2004-12-01

    Cosmogenic nuclides such as 10Be and 26Al have recently become important tools for measuring long-term denudation rates. We have recently shown how cosmogenic nuclide measurements of denudation fluxes can be partitioned into their physical and chemical components, using the enrichment of insoluble tracers in regolith relative to its parent rock. We used these methods to measure long-term rates of physical erosion and chemical weathering for 42 sites, encompassing widely varying climates and denudation rates. Across these sites, mean annual temperatures vary from 2 to 25 ° C, average annual precipitation spans a 20-fold range (from 22 to 420 cm/yr), and denudation rates vary by 32-fold (from 23 to 755 t km-2 yr-2). Our measurements show that chemical weathering rates are tightly coupled with physical erosion rates, such that the relationship between climate and chemical weathering rates may be obscured by site-to-site differences in the rate that minerals are supplied to soil by physical erosion of rock. The relative importance of chemical weathering can be quantified using the "Weathering Intensity Factor" (WIF), the ratio of the chemical weathering rate to the physical erosion rate. Over 60 percent of the variance in WIF's can be explained by a simple Arrhenius-like relationship based on mean annual temperature and average annual precipitation. The temperature-dependence of WIF is roughly half of what one would expect from laboratory measurements of activation energies for feldspar weathering and previous inter-comparisons of short-term average weathering rates from the field. Our results imply that the strength of climate change feedbacks between temperature and silicate weathering rates may be weaker than previously thought, at least in actively eroding, unglaciated granitic terrain similar to our study sites.

  19. Comparative analysis of heavy metal and radionuclide contaminants in Black Sea green and red macroalgae.

    PubMed

    Strezov, A S; Nonova, Tz P

    2005-01-01

    A comparative analysis about the accumulation of heavy metal, natural and technogenic radionuclides from the Black Sea environment in different Bulgarian coastline regions is made. The possibilities to use Chlorophyta and Rhodophyta algae phylums as bioindicators in marine environment are investigated. Environmental contamination in the Black Sea alga species (green and red) was studied from 1992 to 2003. Sampling sites were selected to cover the whole coastal region. Low level gamma spectrometry was used to determine the natural and technogenic nuclide concentrations. The heavy metal concentrations were measured by Atomic Absorption Spectrometry (AAS). The obtained data show that radionuclide and metal concentrations depend on the macrophyte type. Tendencies in the concentration of pollutant variations during the studied period are examined and all data give information about different macrophytic species' ability to accumulate certain elements from one and the same sampling location. All obtained results show that use of macroalgae in marine environmental monitoring reduces the need for complex studies on chemical speciation of aquatic contaminants and makes algae valuable indicators for seawater quality assessment. All data show the lack of serious pollution along the Bulgarian Black Sea coast.

  20. Targets of uranium, plutonium, and curium for heavy-element research

    NASA Astrophysics Data System (ADS)

    Lobanov, Yu. V.; Buklanov, G. V.; Abdullin, F. Sh.; Polyakov, A. N.; Shirokovsky, I. V.; Tsyganov, Yu. S.; Utyonkov, V. K.

    1997-02-01

    The heavy-element research program of the Dubna gas-filled recoil separator requires the use of rather exotic, strongly radioactive targets which can withstand long-term, high-intensity heavy-ion bombardments. A number of targets with thicknesses of 0.1-0.8 mg/cm 2 deposited on various backings by different techniques such as electrospraying, mechanical painting with organic solutions, as well as molecular plating or electrodeposition from organic solutions were tested. The best results were obtained for electroplated targets deposited on 1.5 μm Ti backings. Isotopically enriched targets of 235,236,238U, 242,244Pu, and 248Cm mounted on rotating disks were irradiated by ions ranging from neon to argon with intensities up to 2 × 10 13pps delivered by the U400 cyclotron. During two months of irradiation the total beam dose of the 34S ions applied to the target of 244Pu reached 2.5 × 10 19. Collaborative Dubna-Livermore experiments were performed in 1993-1995 by employing the Dubna gas-filled recoil separator and resulted in the discovery of the new nuclides 262104, 265106, 266106, 267108, and 273110. The experiments aimed at the synthesis of element 114 are under preparation. Target fabrication methods and experimental results for nuclear physics studies at Coulomb energies are described.

  1. Supernova heavy element nucleosynthesis: Can it tell us about neutrino masses?

    SciTech Connect

    Fuller, George M.

    1997-05-20

    Here we describe a new probe of neutrino properties based on heavy element nucleosynthesis. This technique is in many ways akin to the familiar light element Primordial Nucleosynthesis probe of conditions in the early universe. Our new probe is based on the fact that neutrino masses and vacuum mixings can engender matter-enhanced neutrino flavor transformation in the post core bounce supernova environment. Transformations of the type {nu}{sub {mu}}{sub (r)}<-->{nu}{sub e} in this site will have significant effects on the synthesis of the rapid neutron capture (r-Process) elements and the light p-nuclei. We suggest that an understanding of the origin of these nuclides, combined with the measured abundances of these species, may provide a ''Rosetta Stone'' for neutrino properties. Heavy element nucleosynthesis abundance considerations give either constraints/evidence for neutrino masses and flavor mixings, or strong constraints on the site of origin of r-Process nucleosynthesis. The putative limits on neutrino characteristics are complimentary to those derived from laboratory neutrino oscillation studies and solar and atmospheric neutrino experiments. Preliminary studies show that the existence of r-Process nuclei in the abundances observed in the Galaxy cannot be understood unless neutrinos have small masses (possibly in the cosmologically significant range)

  2. The Origins of Light and Heavy R-process Elements Identified by Chemical Tagging of Metal-poor Stars

    NASA Astrophysics Data System (ADS)

    Tsujimoto, Takuji; Shigeyama, Toshikazu

    2014-11-01

    Growing interests in neutron star (NS) mergers as the origin of r-process elements have sprouted since the discovery of evidence for the ejection of these elements from a short-duration γ-ray burst. The hypothesis of a NS merger origin is reinforced by a theoretical update of nucleosynthesis in NS mergers successful in yielding r-process nuclides with A > 130. On the other hand, whether the origin of light r-process elements are associated with nucleosynthesis in NS merger events remains unclear. We find a signature of nucleosynthesis in NS mergers from peculiar chemical abundances of stars belonging to the Galactic globular cluster M15. This finding combined with the recent nucleosynthesis results implies a potential diversity of nucleosynthesis in NS mergers. Based on these considerations, we are successful in the interpretation of an observed correlation between [light r-process/Eu] and [Eu/Fe] among Galactic halo stars and accordingly narrow down the role of supernova nucleosynthesis in the r-process production site. We conclude that the tight correlation by a large fraction of halo stars is attributable to the fact that core-collapse supernovae produce light r-process elements while heavy r-process elements such as Eu and Ba are produced by NS mergers. On the other hand, stars in the outlier, composed of r-enhanced stars ([Eu/Fe] gsim +1) such as CS22892-052, were exclusively enriched by matter ejected by a subclass of NS mergers that is inclined to be massive and consist of both light and heavy r-process nuclides.

  3. THE ORIGINS OF LIGHT AND HEAVY R-PROCESS ELEMENTS IDENTIFIED BY CHEMICAL TAGGING OF METAL-POOR STARS

    SciTech Connect

    Tsujimoto, Takuji; Shigeyama, Toshikazu

    2014-11-01

    Growing interests in neutron star (NS) mergers as the origin of r-process elements have sprouted since the discovery of evidence for the ejection of these elements from a short-duration γ-ray burst. The hypothesis of a NS merger origin is reinforced by a theoretical update of nucleosynthesis in NS mergers successful in yielding r-process nuclides with A > 130. On the other hand, whether the origin of light r-process elements are associated with nucleosynthesis in NS merger events remains unclear. We find a signature of nucleosynthesis in NS mergers from peculiar chemical abundances of stars belonging to the Galactic globular cluster M15. This finding combined with the recent nucleosynthesis results implies a potential diversity of nucleosynthesis in NS mergers. Based on these considerations, we are successful in the interpretation of an observed correlation between [light r-process/Eu] and [Eu/Fe] among Galactic halo stars and accordingly narrow down the role of supernova nucleosynthesis in the r-process production site. We conclude that the tight correlation by a large fraction of halo stars is attributable to the fact that core-collapse supernovae produce light r-process elements while heavy r-process elements such as Eu and Ba are produced by NS mergers. On the other hand, stars in the outlier, composed of r-enhanced stars ([Eu/Fe] ≳ +1) such as CS22892-052, were exclusively enriched by matter ejected by a subclass of NS mergers that is inclined to be massive and consist of both light and heavy r-process nuclides.

  4. Methods of increasing the performance of radionuclide generators used in nuclear medicine: daughter nuclide build-up optimisation, elution-purification-concentration integration, and effective control of radionuclidic purity.

    PubMed

    Le, Van So; Do, Zoe Phuc-Hien; Le, Minh Khoi; Le, Vicki; Le, Natalie Nha-Truc

    2014-06-10

    Methods of increasing the performance of radionuclide generators used in nuclear medicine radiotherapy and SPECT/PET imaging were developed and detailed for 99Mo/99mTc and 68Ge/68Ga radionuclide generators as the cases. Optimisation methods of the daughter nuclide build-up versus stand-by time and/or specific activity using mean progress functions were developed for increasing the performance of radionuclide generators. As a result of this optimisation, the separation of the daughter nuclide from its parent one should be performed at a defined optimal time to avoid the deterioration in specific activity of the daughter nuclide and wasting stand-by time of the generator, while the daughter nuclide yield is maintained to a reasonably high extent. A new characteristic parameter of the formation-decay kinetics of parent/daughter nuclide system was found and effectively used in the practice of the generator production and utilisation. A method of "early elution schedule" was also developed for increasing the daughter nuclide production yield and specific radioactivity, thus saving the cost of the generator and improving the quality of the daughter radionuclide solution. These newly developed optimisation methods in combination with an integrated elution-purification-concentration system of radionuclide generators recently developed is the most suitable way to operate the generator effectively on the basis of economic use and improvement of purposely suitable quality and specific activity of the produced daughter radionuclides. All these features benefit the economic use of the generator, the improved quality of labelling/scan, and the lowered cost of nuclear medicine procedure. Besides, a new method of quality control protocol set-up for post-delivery test of radionuclidic purity has been developed based on the relationship between gamma ray spectrometric detection limit, required limit of impure radionuclide activity and its measurement certainty with respect to

  5. Heavy snowfall damage Virginia pine

    Treesearch

    Richard H. Fenton

    1959-01-01

    In the Coastal Plain from Virginia to Pennsylvania, snowstorms heavy enough to damage trees are unusual. Weather Bureau records for the general area show that heavy snowfall - 8 to 25 inches in a single storm - occurs at an average frequency of about once in 7 years.

  6. Heavy Equipment Mechanic. Instructor Edition.

    ERIC Educational Resources Information Center

    Hendrix, Laborn J.; And Others

    This manual is intended to assist heavy equipment instructors in teaching the latest concepts and functions of heavy equipment. It includes 7 sections and 27 instructional units. Sections (and units) are: orientation (shop safety and first aid, hand tools and miscellaneous tools, measuring, basic rigging and hoisting), engines (basic engine…

  7. Heavy Equipment Mechanic. Instructor Edition.

    ERIC Educational Resources Information Center

    Hendrix, Laborn J.; And Others

    This manual is intended to assist heavy equipment instructors in teaching the latest concepts and functions of heavy equipment. It includes 7 sections and 27 instructional units. Sections (and units) are: orientation (shop safety and first aid, hand tools and miscellaneous tools, measuring, basic rigging and hoisting), engines (basic engine…

  8. Heavy Equipment Mechanic Program Guide.

    ERIC Educational Resources Information Center

    Georgia Univ., Athens. Dept. of Vocational Education.

    Designed to train an entry-level mechanic, this heavy equipment mechanic program guide presents the standard curriculum for technical institutes in Georgia. The curriculum addresses the minimum competencies for a heavy equipment mechanic program. The general information section contains the following: purpose and objectives; program description,…

  9. Heavy hadrons in nuclear matter

    NASA Astrophysics Data System (ADS)

    Hosaka, Atsushi; Hyodo, Tetsuo; Sudoh, Kazutaka; Yamaguchi, Yasuhiro; Yasui, Shigehiro

    2017-09-01

    Current studies on heavy hadrons in nuclear medium are reviewed with a summary of the basic theoretical concepts of QCD, namely chiral symmetry, heavy quark spin symmetry, and the effective Lagrangian approach. The nuclear matter is an interesting place to study the properties of heavy hadrons from many different points of view. We emphasize the importance of the following topics: (i) charm/bottom hadron-nucleon interaction, (ii) structure of charm/bottom nuclei, and (iii) QCD vacuum properties and hadron modifications in nuclear medium. We pick up three different groups of heavy hadrons, quarkonia (J / ψ, ϒ), heavy-light mesons (D/ D ¯ , B ¯ / B) and heavy baryons (Λc, Λb). The modifications of those hadrons in nuclear matter provide us with important information to investigate the essential properties of heavy hadrons. We also give the discussions about the heavy hadrons, not only in infinite nuclear matter, but also in finite-size atomic nuclei with finite baryon numbers, to serve future experiments.

  10. HEAVY ION LINEAR ACCELERATOR

    DOEpatents

    Van Atta, C.M.; Beringer, R.; Smith, L.

    1959-01-01

    A linear accelerator of heavy ions is described. The basic contributions of the invention consist of a method and apparatus for obtaining high energy particles of an element with an increased charge-to-mass ratio. The method comprises the steps of ionizing the atoms of an element, accelerating the resultant ions to an energy substantially equal to one Mev per nucleon, stripping orbital electrons from the accelerated ions by passing the ions through a curtain of elemental vapor disposed transversely of the path of the ions to provide a second charge-to-mass ratio, and finally accelerating the resultant stripped ions to a final energy of at least ten Mev per nucleon.

  11. Disorders of heavy metals.

    PubMed

    Woimant, France; Trocello, Jean-Marc

    2014-01-01

    Heavy metals and trace elements play an important role in relation to the physiology and pathology of the nervous system. Neurologic diseases related to disorders of metabolism of copper and iron are reviewed. Copper disorders are divided into two classes: ATP7A- or ATP7B-related inherited copper transport disorders (Menkes disease, occipital horn syndrome, ATP7A-related distal motor neuropathy, and Wilson disease) and acquired diseases associated with copper deficiency or copper excess. Iron brain disorders are divided into genetic neurodegeneration with brain iron accumulation (NBIA, neuroferritinopathy, and aceruloplasminemia), genetic systemic iron accumulation with neurologic features (hemochromatosis), and acquired diseases associated with iron excess (superficial siderosis) or iron deficiency (restless leg syndrome). The main features of cadmium, lead, aluminum, mercury, and manganese toxicity are summarized.

  12. Heavy ion beam probing

    SciTech Connect

    Hickok, R L

    1980-07-01

    This report consists of the notes distributed to the participants at the IEEE Mini-Course on Modern Plasma Diagnostics that was held in Madison, Wisconsin in May 1980. It presents an overview of Heavy Ion Beam Probing that briefly describes the principles and discuss the types of measurements that can be made. The problems associated with implementing beam probes are noted, possible variations are described, estimated costs of present day systems, and the scaling requirements for large plasma devices are presented. The final chapter illustrates typical results that have been obtained on a variety of plasma devices. No detailed calculations are included in the report, but a list of references that will provide more detailed information is included.

  13. New, heavy transuranium isotopes

    SciTech Connect

    Hulet, E.K.

    1990-10-22

    In this report, we offer our most recent results concerning the decay properties for five new isotopes of Md, No, Lr, and for {sup 258m}Md. In additions to these successful experiments, we have also conducted searches for {sup 263}(105), {sup 264}(105), {sup 272}(109), and superheavy elements from bombardments of {sup 254}Es with heavy ions. {sup 2} An exciting finding in the course of this work is a new fission phenomenon, which we have termed bidmodal fission''. This is described in a subsequent section. The final part summarizes our conclusions based on the unexpectedly long half-lives and surprising fission properties of the heaviest nuclei. 27 refs., 19 figs.

  14. Atwood's Heavy Chain

    NASA Astrophysics Data System (ADS)

    Beeken, Paul

    2011-11-01

    While perusing various websites in search of a more challenging lab for my students, I came across a number of ideas where replacing the string in an Atwood's machine with a simple ball chain like the kind found in lamp pulls created an interesting system to investigate. The replacement of the string produced a nice nonuniform acceleration, but one that my AP® students found difficult to analyze given their current math background. As the year progressed, we began to explore the importance of work and its utility in making predictions on systems that did not lend themselves to easy analysis using Newtonian mechanics. The effort made it apparent that the heavy rope Atwood's machine would make a perfect system for investigation using the lessons gained from work and energy.

  15. Heavy Quarkonium Spectroscopy

    SciTech Connect

    Faccini, Riccardo; /Rome U. /INFN, Rome

    2008-02-22

    Although the Standard Model of elementary particles is well established, strong interactions are not yet fully under control. We believe QCD is the field theory capable of describing them, but we are not yet capable, in most of the cases, to make exact predictions. Systems that include heavy quark-antiquark pairs (quarkonia) are ideal and unique laboratories to probe both the high energy regimes of QCD, where an expansion in terms of the coupling constant is possible, and the low energy regimes, where non-perturbative effects dominate. In the last years this field is experiencing a rapid expansion with a wealth of new data coming in from diverse sources: data on quarkonium formation from dedicated experiments (BES at BEPC, KEDR at VEPP-4M CLEO-c at CESR), clear samples produced by high luminosity B-factories (PEP and KEKB), and very large samples produced from gluon-gluon fusion in p{bar p} annihilations at Tevatron (CDF and D0 experiments). In this review I will first summarize recent developments in the understanding of heavy quarkonium states which have a well established quark content. Next, the core of the paper will be spent to review the experimental evidences of new states that might be aggregations of more than just a quark-antiquark pair. Although the possibility to have bound states of two quarks and two antiquarks or of quark-antiquark pairs and gluons has been predicted since the very start of the quark model [2], no observed state has yet been attributed to one of them: achieving such an attribution would be a major step in the understanding of the strong interactions.

  16. Results of heavy ion radiotherapy

    SciTech Connect

    Castro, J.R.

    1994-04-01

    The potential of heavy ion therapy for clinical use in cancer therapy stems from the biological parameters of heavy charged particles, and their precise dose localization. Biologically, carbon, neon and other heavy ion beams (up to about silicon) are clinically useful in overcoming the radioresistance of hypoxic tumors, thus increasing biological effectiveness relative to low-LET x-ray or electron beams. Cells irradiated by heavy ions show less variation in cell-cycle related radiosensitivity and decreased repair of radiation injury. The physical parameters of these heavy charged particles allow precise delivery of high radiation doses to tumors while minimizing irradiation of normal tissues. Clinical use requires close interaction between radiation oncologists, medical physicists, accelerator physicists, engineers, computer scientists and radiation biologists.

  17. Managing Inventories of Heavy Actinides

    SciTech Connect

    Wham, Robert M; Patton, Bradley D

    2011-01-01

    The Department of Energy (DOE) has stored a limited inventory of heavy actinides contained in irradiated targets, some partially processed, at the Savannah River Site (SRS) and Oak Ridge National Laboratory (ORNL). The 'heavy actinides' of interest include plutonium, americium, and curium isotopes; specifically 242Pu and 244Pu, 243Am, and 244/246/248Cm. No alternate supplies of these heavy actinides and no other capabilities for producing them are currently available. Some of these heavy actinide materials are important for use as feedstock for producing heavy isotopes and elements needed for research and commercial application. The rare isotope 244Pu is valuable for research, environmental safeguards, and nuclear forensics. Because the production of these heavy actinides was made possible only by the enormous investment of time and money associated with defense production efforts, the remaining inventories of these rare nuclear materials are an important part of the legacy of the Nuclear Weapons Program. Significant unique heavy actinide inventories reside in irradiated Mark-18A and Mark-42 targets at SRS and ORNL, with no plans to separate and store the isotopes for future use. Although the costs of preserving these heavy actinide materials would be considerable, for all practical purposes they are irreplaceable. The effort required to reproduce these heavy actinides today would likely cost billions of dollars and encompass a series of irradiation and chemical separation cycles for at least 50 years; thus, reproduction is virtually impossible. DOE has a limited window of opportunity to recover and preserve these heavy actinides before they are disposed of as waste. A path forward is presented to recover and manage these irreplaceable National Asset materials for future use in research, nuclear forensics, and other potential applications.

  18. Heavy Flavor Physics in STAR

    NASA Astrophysics Data System (ADS)

    Videbæk, Flemming; STAR Collaboration

    2013-03-01

    In relativistic heavy-ion collisions at RHIC, heavy quarks are primarily created from initial hard scatterings. Since their large masses are not easily affected by the strong interaction with QCD medium they may carry information from the system at early stage. The interaction between heavy quarks and the medium is sensitive to the medium dynamics; therefore heavy quarks are suggested as an ideal probe to quantify the properties of the strongly interacting QCD matter. The STAR Collaboration should complete the Heavy Flavor Tracker (HFT) and the Muon Telescope Detector (MTD) upgrades by 2014. These detectors will greatly enhance the STAR physics capability to measure heavy quark collectivity and correlations using topologically reconstructed charmed hadrons and heavy quark decay electron-muon correlations. In addition, measurements of the quarkonium muon decay channels will enable us to separate Upsilon 1S from 2S and 3S states in p + p and A+A collisions. Selected STAR results on open charm and quarkonia production in p + p and Au+Au collisions at 200 GeV are presented. An overview of the upgrades, their expected performance and current status is presented.

  19. Imaging using accelerated heavy ions

    SciTech Connect

    Chu, W.T.

    1982-05-01

    Several methods for imaging using accelerated heavy ion beams are being investigated at Lawrence Berkeley Laboratory. Using the HILAC (Heavy-Ion Linear Accelerator) as an injector, the Bevalac can accelerate fully stripped atomic nuclei from carbon (Z = 6) to krypton (Z = 34), and partly stripped ions up to uranium (Z = 92). Radiographic studies to date have been conducted with helium (from 184-inch cyclotron), carbon, oxygen, and neon beams. Useful ranges in tissue of 40 cm or more are available. To investigate the potential of heavy-ion projection radiography and computed tomography (CT), several methods and instrumentation have been studied.

  20. Heavy Hybrids: decay to and mixing with Heavy Quarkonium

    NASA Astrophysics Data System (ADS)

    Oncala, Rubén; Soto, Joan

    2017-03-01

    We report on a recent QCD based research on hybrid mesons containing cc¯ or bb¯ quarks. We present results for the spectrum, the decay widths to heavy quarkonium, and the role of mixing with the latter. We point out that mixing with heavy quarkonium provides a potentially large source of spin symmetry breaking. We identify candidates to hybrid mesons among the so called XYZ states in the charmonium and bottomonium spectrum.

  1. Illusory Late Heavy Bombardments

    PubMed Central

    Boehnke, Patrick; Harrison, T. Mark

    2016-01-01

    The Late Heavy Bombardment (LHB), a hypothesized impact spike at ∼3.9 Ga, is one of the major scientific concepts to emerge from Apollo-era lunar exploration. A significant portion of the evidence for the existence of the LHB comes from histograms of 40Ar/39Ar “plateau” ages (i.e., regions selected on the basis of apparent isochroneity). However, due to lunar magmatism and overprinting from subsequent impact events, virtually all Apollo-era samples show evidence for 40Ar/39Ar age spectrum disturbances, leaving open the possibility that partial 40Ar* resetting could bias interpretation of bombardment histories due to plateaus yielding misleadingly young ages. We examine this possibility through a physical model of 40Ar* diffusion in Apollo samples and test the uniqueness of the impact histories obtained by inverting plateau age histograms. Our results show that plateau histograms tend to yield age peaks, even in those cases where the input impact curve did not contain such a spike, in part due to the episodic nature of lunar crust or parent body formation. Restated, monotonically declining impact histories yield apparent age peaks that could be misinterpreted as LHB-type events. We further conclude that the assignment of apparent 40Ar/39Ar plateau ages bears an undesirably high degree of subjectivity. When compounded by inappropriate interpretations of histograms constructed from plateau ages, interpretation of apparent, but illusory, impact spikes is likely. PMID:27621460

  2. Heavy-element nucleosynthesis

    SciTech Connect

    Mathews, G.J.

    1990-10-30

    New measurements and theoretical studies of nuclear properties, together with new astronomical data on the growth of heavy-element abundances during the early history of the Galaxy, now provide a clearer picture of where in nature the elements heavier than iron are produced by rapid (r-process) and show (s-process) neutron capture reactions. The nuclear data suggest that the r-process involves a high-neutron-density beta-flow equilibrium environment and that the s-process may have occurred at a temperature and neutron density consistent with a {sup 13}C({alpha},n){sup 16}0 neutron source. The astronomical data, when compared with simple galactic chemical evolution modes, suggests that the r-process is associated with type II supernovae and that the neutron source must be manufactured by the star. Low-mass type II supernovae are proposed as the most important contributors to the r-process. A {sup 13}C neutron source in intermediate-mass stars is proposed for the s-process. 64 refs., 7 figs.

  3. Biosorption of heavy metals

    SciTech Connect

    Volesky, B. |; Holan, Z.R.

    1995-05-01

    Only within the past decade has the potential of metal biosorption by biomass materials been well established. For economic reasons, of particular interest are abundant biomass types generated as a waste byproduct of large-scale industrial fermentations or certain metal-binding algae found in large quantities in the sea. These biomass types serve as a basis for newly developed metal biosorption processes foreseen particularly as a very competitive means for the detoxification of metal-bearing industrial effluents. The assessment of the metal-building capacity of some new biosorbents is discussed. Lead and cadmium, for instance, have been effectively removed from very dilute solutions by the dried biomass of some ubiquitous species of brown marine algae such as Ascophyllum and Sargassum, which accumulate more than 30% of biomass dry weight in the metal. Mycelia of the industrial steroid-transforming fungi Rhizopus and Absidia are excellent biosorbents for lead, cadmium, copper, zinc, and uranium and also bind other heavy metals up to 25% of the biomass dry weight. Biosorption isotherm curves, derived from equilibrium batch sorption experiments, are used in the evaluation of metal uptake by different biosorbents. Further studies are focusing on the assessment of biosorbent performance in dynamic continuous-flow sorption systems. In the course of this work, new methodologies are being developed that are aimed at mathematical modeling of biosorption systems and their effective optimization. 115 refs., 7 figs., 3 tabs.

  4. Heavy fields and gravity

    NASA Astrophysics Data System (ADS)

    Goon, Garrett

    2017-01-01

    We study the effects of heavy fields on 4D spacetimes with flat, de Sitter and anti-de Sitter asymptotics. At low energies, matter generates specific, calculable higher derivative corrections to the GR action which perturbatively alter the Schwarzschild-( A) dS family of solutions. The effects of massive scalars, Dirac spinors and gauge fields are each considered. The six-derivative operators they produce, such as ˜ R 3 terms, generate the leading corrections. The induced changes to horizon radii, Hawking temperatures and entropies are found. Modifications to the energy of large AdS black holes are derived by imposing the first law. An explicit demonstration of the replica trick is provided, as it is used to derive black hole and cosmological horizon entropies. Considering entropy bounds, it's found that scalars and fermions increase the entropy one can store inside a region bounded by a sphere of fixed size, but vectors lead to a decrease, oddly. We also demonstrate, however, that many of the corrections fall below the resolving power of the effective field theory and are therefore untrustworthy. Defining properties of black holes, such as the horizon area and Hawking temperature, prove to be remarkably robust against higher derivative gravitational corrections.

  5. Illusory Late Heavy Bombardments.

    PubMed

    Boehnke, Patrick; Harrison, T Mark

    2016-09-27

    The Late Heavy Bombardment (LHB), a hypothesized impact spike at ∼3.9 Ga, is one of the major scientific concepts to emerge from Apollo-era lunar exploration. A significant portion of the evidence for the existence of the LHB comes from histograms of (40)Ar/(39)Ar "plateau" ages (i.e., regions selected on the basis of apparent isochroneity). However, due to lunar magmatism and overprinting from subsequent impact events, virtually all Apollo-era samples show evidence for (40)Ar/(39)Ar age spectrum disturbances, leaving open the possibility that partial (40)Ar* resetting could bias interpretation of bombardment histories due to plateaus yielding misleadingly young ages. We examine this possibility through a physical model of (40)Ar* diffusion in Apollo samples and test the uniqueness of the impact histories obtained by inverting plateau age histograms. Our results show that plateau histograms tend to yield age peaks, even in those cases where the input impact curve did not contain such a spike, in part due to the episodic nature of lunar crust or parent body formation. Restated, monotonically declining impact histories yield apparent age peaks that could be misinterpreted as LHB-type events. We further conclude that the assignment of apparent (40)Ar/(39)Ar plateau ages bears an undesirably high degree of subjectivity. When compounded by inappropriate interpretations of histograms constructed from plateau ages, interpretation of apparent, but illusory, impact spikes is likely.

  6. Consideration of geomorphological uncertainties with terrestrial cosmogenic nuclide dating (TCND): combining Schmidt-hammer and 10Be dating, Southern Alps, New Zealand

    NASA Astrophysics Data System (ADS)

    Winkler, Stefan

    2010-05-01

    As the importance of glaciers as key indicators of global change has increased during recent years, investigating Holocene glaciers chronologies has gained higher attention accordingly. One reason is the need for a better understanding of the climate - glacier relationship. Comparative studies play a major role in this field of research owing to the natural diversity of glacier behaviour. Detailed Holocene glacier chronologies are, furthermore, necessary to verify and eventually adjust glacier models indispensable for many attempts to predict future glacier changes. The Southern Alps of New Zealand are one of the few key study areas on the Southern Hemisphere where, in general, evidence is still sparse compared to its Northern counterpart. Improvement and reassessment of the Late Holocene glacier chronology in this region is, therefore, an important goal of current research. Recently, terrestrial (in situ) cosmogenic nuclide (10Be) surface exposure dating has been increasingly applied to Holocene moraines in New Zealand and elsewhere. In the context of numerical ("absolute") dating techniques, terrestrial cosmogenic nuclide dating (TCND) seems to have been established as an alternative to the previously dominating radiocarbon (14C) dating of organic material (plant remains, organic-rich soil layers etc.) buried beneath or within moraines. Precision and time resolution achieved by the newest laboratory standards and procedures (Schaefer et al. 2009) is truly a milestone and will promote future attempts of TCND in any comparable context. Maybe, TCND has the potential to at least partially replace radiocarbon (14C) dating in its dominating role for the "absolute" dating of Holocene glacial deposits. By contrast, field sampling for TCND often lacks appropriate consideration of geomorphological uncertainties. Whereas much effort is made with the high precision results achieved in the laboratory, the choice of boulders sampled on Holocene moraines is often purely made

  7. Neutron-induced fission of even- and odd-mass plutonium isotopes within a four-dimensional Langevin framework

    NASA Astrophysics Data System (ADS)

    Pahlavani, M. R.; Mirfathi, S. M.

    2017-07-01

    Neutron multiplicity prior to scission and evaluation of mass distribution of fission fragments with the fission time scale for neutron induced fission of plutonium isotopes are investigated using a dynamical Langevin approach. Also, mass yield of fragments and prompt neutron multiplicity in different time scales of the fission process are compared with experimental data. Reasonable agreement is achieved between calculated and available experimental data.

  8. Comparisons of interacting-boson-fermion approximation and triaxial calculations for odd-mass N =80 nuclei

    SciTech Connect

    Aryaeinejad, R.; Chou, W.; McHarris, W.C. )

    1989-09-01

    The interacting-boson-fermion-approximation and triaxial models were used to calculate excitation energies and mixing ratios for the {ital N}=80 nuclei, {sup 139}Pr, {sup 141}Pm, and {sup 143}Eu. For low-lying negative- and positive-parity states both models yield roughly the same numbers, in good agreement with experimental results. For high-lying states we find that the interacting-boson-fermion-approximation model describes the level structure considerably better than the triaxial model. On the other hand, the triaxial model gives more satisfactory results in predicting the mixing ratios.

  9. Evolution of nuclear shapes in odd-mass yttrium and niobium isotopes from lifetime measurements following fission reactions

    NASA Astrophysics Data System (ADS)

    Hagen, T. W.; Görgen, A.; Korten, W.; Grente, L.; Salsac, M.-D.; Farget, F.; Ragnarsson, I.; Braunroth, T.; Bruyneel, B.; Celikovic, I.; Clément, E.; de France, G.; Delaune, O.; Dewald, A.; Dijon, A.; Hackstein, M.; Jacquot, B.; Litzinger, J.; Ljungvall, J.; Louchart, C.; Michelagnoli, C.; Napoli, D. R.; Recchia, F.; Rother, W.; Sahin, E.; Siem, S.; Sulignano, B.; Theisen, Ch.; Valiente-Dobon, J. J.

    2017-03-01

    Lifetimes of excited states in 99Y,101Y,101Nb,103Nb, and 105Nb were measured in an experiment using the recoil distance Doppler shift method at GANIL (Grand Accélérateur National d'Ions Lourds). The neutron-rich nuclei were produced in fission reactions between a 238U beam and a 9Be target. Prompt γ rays were measured with the EXOGAM array and correlated with fission fragments that were identified in mass and atomic number with the VAMOS++ spectrometer. The measured lifetimes, together with branching ratios, provide B (M 1 ) and B (E 2 ) values for the strongly coupled rotational bands built on the [422 ] 5 /2+ ground state in the Y and Nb nuclei with neutron number N ≥60 . The comparison of the experimental results with triaxial particle-rotor calculations provides information about the evolution of the nuclear shape in this mass region.

  10. Ultra Heavy Ion Collector (UHIC)

    NASA Technical Reports Server (NTRS)

    Stone, E. C.

    1997-01-01

    The purpose of this final report is to study the propagation of heavy nuclei in cosmic radiation. Topics include: Mass Distributions of Fragments from the Interactions of 600 MeV/n Silver Nuclei; Charge-pickup by Heavy Relativistic Nuclei; Fragmentation and Propagation Heavy UH Cosmic Ray Nuclei; Nuclear Fragmentation Parameters Needed for Interpretation of Observed Fluxes of UH Cosmic Ray Nuclei; Fragmentation and Electromagnetic Dissociation of 10.6 GeV/nucleon (197) Au Nuclei; Nuclear Interaction Cross Sections for UltraHeavy Nuclei; The Charge-Changing Fragmentation of 10.6 GeV/nucleon 197 Au Nuclei; Fragmentation Cross Sections of Relativistic 84/36 Kr and 109/47 Ag Nuclei in Targets from Hydrogen to Lead; Mission Concept for the Study of Ultraheavy Galactic Cosmic Rays; and Propagation of the Heaviest UH - Cosmic Ray Nuclei.

  11. Heavy quark spectroscopy and decay

    SciTech Connect

    Schindler, R.H.

    1987-01-01

    The understanding of q anti q systems containing heavy, charmed, and bottom quarks has progressed rapidly in recent years, through steady improvements in experimental techniques for production and detection of their decays. These lectures are meant to be an experimentalist's review of the subject. In the first of two lectures, the existing data on the spectroscopy of the bound c anti c and b anti b systems will be discussed. Emphasis is placed on comparisons with the theoretical models. The second lecture covers the rapidly changing subject of the decays of heavy mesons (c anti q and b anti q), and their excited states. In combination, the spectroscopy and decays of heavy quarks are shown to provide interesting insights into both the strong and electroweak interactions of the heavy quarks. 103 refs., 39 figs.

  12. Viscoelastic properties of heavy oils

    NASA Astrophysics Data System (ADS)

    Rojas Luces, Maria Alejandra

    Rheological low frequency measurements were carried out to analyze the viscoelastic properties of four heavy oil samples. At room conditions, the heavy oil samples exhibit non-Newtonian or viscoelastic behavior since they have a viscous component and an elastic component. The latter becomes very important for temperatures below 30°C, and for seismic to ultrasonic frequencies. Above this temperature, the viscous component increases significantly in comparison to the elastic component, and for seismic frequencies heavy oils can be considered as Newtonian fluids. A new viscosity model based on the concept of activation energy was derived to predict viscosity in terms of frequency and temperature for temperatures below 60°C. A new frequency-temperature dispersion model was derived to address the variation of the complex shear modulus (G*) with frequency and temperature for the heavy oil samples. This model fits the data well for seismic and sonic frequencies but it overpredicts G* at ultrasonic frequencies.

  13. Heavy Equipment Mechanic Program Standards.

    ERIC Educational Resources Information Center

    Georgia Univ., Athens. Dept. of Vocational Education.

    This publication contains statewide standards for the heavy equipment mechanic program in Georgia. The standards are divided into 12 categories: foundations (philosophy, purpose, goals, program objectives, availability, evaluation); admissions (admission requirements, provisional admission requirements, recruitment, evaluation and planning);…

  14. CHARACTERIZATION OF GRAPHITE SLEEVES FROM BUGEY 1 EDF PLANT FOR PERMANENT DISPOSAL--MEASUREMENT AND CALCULATION OF SCALING FACTORS FOR DIFFICULT-TO-MEASURE NUCLIDES

    SciTech Connect

    PONCET, Bernard R.

    2003-02-27

    Electricite De France's Bugey-1 reactor, with graphite moderator, was shutdown permanently in 1994. The natural uranium elements are encased in graphite sleeves to facilitate handling. 2,000 m3 of concrete containers, containing non conditioned graphite sleeves, must be characterized and conditioned before shipment to the national repository site called ''Centre de l'Aube''. The characterization work consists in quantifying Difficult-To-Measure nuclides (DTM) by the use of Scaling Factors (SF), which use Co-60 as tracer. Bugey developed an industrial method for the gamma counting of each package to perform easily and rapidly the measurement of the Co-60 content. Depending upon the DTM radionuclide, Co-60 scaling factors are determined, or by measurement on graphite samples (case of C-14, Cl-36, Ni-63, H-3), either by using a calculation technique which is based upon the impurities present in the graphite sleeves. This method is applied for the other pure beta emitters all DTM radionucli des : Ag-108m, Be-10, Ca-41, Cd-109, Cd-113m, Co-57, Cs-135, Cs-137, Eu-155, Fe-55, Gd-153, Mo-93, Nb- 93m, Nb-94, Ni-59, Pd-107, Pm-147, Sm-151, Sn-119m, Sn-121m, Sn-126, Sr-90, Tc-99, V-49 and Zr-93. Calculations use six sleeve history cases : 1 year at 50% power, 2 years at 50 % power, 3 years at 50 % power, 4 years at 50 % power, 1 year at 100 % power and 2 years at 100 % power. The DTM nuclides have been calculated from impurity concentrations for each of these six cases, and the greatest scaling factor has been kept. The calculation is based upon two impurity sets: First impurity set : a reverse activation calculation provides us with the best estimate value of impurities calculated from the measured mean gamma spectrum and from measured scaling factors. It consists in solving a system of simultaneous equations for the impurities as a function of the mean gamma radioactive spectrum and of the measured scaling factors. The concerned calculated impurities are Co, Cl, Li, Ag, Cs

  15. Heavy Metal Stars

    NASA Astrophysics Data System (ADS)

    2001-08-01

    La Silla Telescope Detects Lots of Lead in Three Distant Binaries Summary Very high abundances of the heavy element Lead have been discovered in three distant stars in the Milky Way Galaxy . This finding strongly supports the long-held view that roughly half of the stable elements heavier than Iron are produced in common stars during a phase towards the end of their life when they burn their Helium - the other half results from supernova explosions. All the Lead contained in each of the three stars weighs about as much as our Moon. The observations show that these "Lead stars" - all members of binary stellar systems - have been more enriched with Lead than with any other chemical element heavier than Iron. This new result is in excellent agreement with predictions by current stellar models about the build-up of heavy elements in stellar interiors. The new observations are reported by a team of Belgian and French astronomers [1] who used the Coude Echelle Spectrometer on the ESO 3.6-m telescope at the La Silla Observatory (Chile). PR Photo 26a/01 : A photo of HD 196944 , one of the "Lead stars". PR Photo 26b/01 : A CES spectrum of HD 196944 . The build-up of heavy elements Astronomers and physicists denote the build-up of heavier elements from lighter ones as " nucleosynthesis ". Only the very lightest elements (Hydrogen, Helium and Lithium [2]) were created at the time of the Big Bang and therefore present in the early universe. All the other heavier elements we now see around us were produced at a later time by nucleosynthesis inside stars. In those "element factories", nuclei of the lighter elements are smashed together whereby they become the nuclei of heavier ones - this process is known as nuclear fusion . In our Sun and similar stars, Hydrogen is being fused into Helium. At some stage, Helium is fused into Carbon, then Oxygen, etc. The fusion process requires positively charged nuclei to move very close to each other before they can unite. But with increasing

  16. LCLS Heavy Met Outgassing Tests

    SciTech Connect

    Kishiyama, K. I.

    2010-12-01

    A Heavy Met that is 95% tungsten, 3% nickel and 2% iron and sintered to 100% density and is Ultra High Vacuum (UHV) compatible is proposed for use as the X-ray slit in the Front End Enclosure and the Fixed Mask for the Linac Coherent Light Source (LCLS). The Heavy Met was tested in the LLNL Vacuum Sciences and Engineering Lab (VSEL) to determine its outgassing rate and its overall compatibility with the vacuum requirements for LCLS.

  17. Conversion of heavy petroleum oils

    SciTech Connect

    Farcasiu, M.

    1982-03-02

    Heavy petroleum oils, such as vacuum resids, and heavy fractions of tar sands and shale oil, are partially converted to more volatile hydrocarbons by mixing with light aromatic hydrocarbons and treatment of the mixture with a friedel-crafts catalyst such as aluminum chloride. It is believed that the conversion found is essentially a transalkylation, I.E. The resid undergoes dealkylation with concurrent alkylation of the light aromatic hydrocarbon.

  18. Phenomenology of heavy quark systems

    SciTech Connect

    Gilman, F.J.

    1987-03-01

    The spectroscopy of heavy quark systems is examined with regards to spin independent and spin dependent potentials. It is shown that a qualitative picture exists of the spin-independent forces, and that a semi-quantitative understanding exists for the spin-dependent effects. A brief review is then given of the subject of the decays of hadrons containing heavy quarks, including weak decays at the quark level, and describing corrections to the spectator model. (LEW)

  19. Hysterectomy for heavy menstrual bleeding.

    PubMed

    van der Meij, Eva; Emanuel, Mark Hans

    2016-01-01

    Hysterectomy is the most frequently performed major surgical intervention in gynecology. Although surgically removing the uterus is invasive, it represents the most definitive treatment option for heavy menstrual bleeding. In this article, we will discuss the indications for hysterectomy as a treatment for heavy menstrual bleeding, the different approaches to perform the hysterectomy, the complications which may occur during and after this procedure and finally the outcomes in comparison with other treatment options.

  20. Illusory Late Heavy Bombardments

    NASA Astrophysics Data System (ADS)

    Boehnke, P.; Harrison, M.

    2016-12-01

    The Late Heavy Bombardment (LHB), a hypothesized impact spike at 3.9 Ga, is one of the major scientific concepts to emerge from Apollo-era lunar exploration and a significant portion of the evidence now marshaled for its existence comes from histograms of 40Ar/39Ar "plateau" ages. Despite the lack of erosion and plate tectonics, the lunar crust does not retain a perfect impact record due to protracted crust formation, lunar volcanism, and overprinting from subsequent impact events. Indeed, virtually all Apollo-era samples show 40Ar/39Ar age spectrum disturbances due to later re-heating events. This provides evidence that partial 40Ar resetting is a significant feature of lunar 40Ar/39Ar analyses which could bias interpretation of bombardment histories due to "plateau" ages being misleadingly young. In order to examine the effects of partial resetting on the inference of bombardment histories from "plateau" ages, we combine chronologic information derived from the early heating steps of each 40Ar/39Ar analysis, as this represents a good approximation of the timing of the last reheating event, with a first-order physical model of 40Ar* diffusion in Apollo samples. We use this modeling framework and data compilation to examine the uniqueness of inverting "plateau" age histograms from synthetic impact histories. Our results show that "plateau" histograms tend to yield age peaks, even in those cases where the input impact history did not contain such a spike. That is, monotonically declining impact histories yield apparent episodes that could be misinterpreted as LHB-type events. Since H-chondrites and HED meteorites also show apparent impact spikes, we extend our conclusions to impact histories for meteorite parent bodies as well. We conclude that the assignment of apparent "plateau" ages bears an undesirably high degree of subjectivity. When compounded by inappropriately simplistic interpretations of histograms constructed from such "plateau" ages, impact spikes that

  1. Heavy smoking and liver.

    PubMed

    El-Zayadi, Abdel-Rahman

    2006-10-14

    Smoking causes a variety of adverse effects on organs that have no direct contact with the smoke itself such as the liver. It induces three major adverse effects on the liver: direct or indirect toxic effects, immunological effects and oncogenic effects. Smoking yields chemical substances with cytotoxic potential which increase necro-inflammation and fibrosis. In addition, smoking increases the production of pro-inflammatory cytokines (IL-1, IL-6 and TNF- alpha) that would be involved in liver cell injury. It contributes to the development of secondary polycythemia and in turn to increased red cell mass and turnover which might be a contributing factor to secondary iron overload disease promoting oxidative stress of hepatocytes. Increased red cell mass and turnover are associated with increased purine catabolism which promotes excessive production of uric acid. Smoking affects both cell-mediated and humoral immune responses by blocking lymphocyte proliferation and inducing apoptosis of lymphocytes. Smoking also increases serum and hepatic iron which induce oxidative stress and lipid peroxidation that lead to activation of stellate cells and development of fibrosis. Smoking yields chemicals with oncogenic potential that increase the risk of hepatocellular carcinoma (HCC) in patients with viral hepatitis and are independent of viral infection as well. Tobacco smoking has been associated with suppression of p53 (tumour suppressor gene). In addition, smoking causes suppression of T-cell responses and is associated with decreased surveillance for tumour cells. Moreover, it has been reported that heavy smoking affects the sustained virological response to interferon (IFN) therapy in hepatitis C patients which can be improved by repeated phlebotomy. Smoker's syndrome is a clinico-pathological condition where patients complain of episodes of facial flushing, warmth of the palms and soles of feet, throbbing headache, fullness in the head, dizziness, lethargy, prickling

  2. Disentangling heavy flavor at colliders

    NASA Astrophysics Data System (ADS)

    Ilten, Philip; Rodd, Nicholas L.; Thaler, Jesse; Williams, Mike

    2017-09-01

    We propose two new analysis strategies for studying charm and beauty quarks at colliders. The first strategy is aimed at testing the kinematics of heavy-flavor quarks within an identified jet. Here, we use the SoftDrop jet-declustering algorithm to identify two subjets within a large-radius jet, using subjet flavor tagging to test the heavy-quark splitting functions of QCD. For subjets containing a J /ψ or ϒ , this declustering technique can also help probe the mechanism for quarkonium production. The second strategy is aimed at isolating heavy-flavor production from gluon splitting. Here, we introduce a new FlavorCone algorithm, which smoothly interpolates from well-separated heavy-quark jets to the gluon-splitting regime where jets overlap. Because of its excellent ability to identify charm and beauty hadrons, the LHCb detector is ideally suited to pursue these strategies, though similar measurements should also be possible at ATLAS and CMS. Together, these SoftDrop and FlavorCone studies should clarify a number of aspects of heavy-flavor physics at colliders, and provide crucial information needed to improve heavy-flavor modeling in parton-shower generators.

  3. The heavy quark expansion of QCD

    SciTech Connect

    Falk, A.F.

    1997-06-01

    These lectures contain an elementary introduction to heavy quark symmetry and the heavy quark expansion. Applications such as the expansion of heavy meson decay constants and the treatment of inclusive and exclusive semileptonic B decays are included. Heavy hadron production via nonperturbative fragmentation processes is also discussed. 54 refs., 7 figs.

  4. Suppression and Two-Particle Correlations of Heavy Mesons in Heavy-Ion Collisions

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

    We study the medium modification of heavy quarks produced in heavy-ion collisions. The evolution of heavy quarks inside the QGP is described using a modified Langevin framework that simultaneously incorporates their collisional and radiative energy loss. Within this framework, we provide good descriptions of the heavy meson suppression and predictions for the two-particle correlation functions of heavy meson pairs.

  5. Authigenic 10Be/9Be ratio signatures of the cosmogenic nuclide production linked to geomagnetic dipole moment variation since the Brunhes/Matuyama boundary

    NASA Astrophysics Data System (ADS)

    Simon, Quentin; Thouveny, Nicolas; Bourlès, Didier L.; Valet, Jean-Pierre; Bassinot, Franck; Ménabréaz, Lucie; Guillou, Valéry; Choy, Sandrine; Beaufort, Luc

    2016-11-01

    Geomagnetic dipole moment variations associated with polarity reversals and excursions are expressed by large changes of the cosmogenic nuclide beryllium-10 (10Be) production rates. Authigenic 10Be/9Be ratios (proxy of atmospheric 10Be production) from oceanic cores therefore complete the classical information derived from relative paleointensity (RPI) records. This study presents new authigenic 10Be/9Be ratio results obtained from cores MD05-2920 and MD05-2930 collected in the west equatorial Pacific Ocean. Be ratios from cores MD05-2920, MD05-2930 and MD90-0961 have been stacked and averaged. Variations of the authigenic 10Be/9Be ratio are analyzed and compared with the geomagnetic dipole low series reported from global RPI stacks. The largest 10Be overproduction episodes are related to dipole field collapses (below a threshold of 2 × 1022 Am2) associated with the Brunhes/Matuyama reversal, the Laschamp (41 ka) excursion, and the Iceland Basin event (190 ka). Other significant 10Be production peaks are correlated to geomagnetic excursions reported in literature. The record was then calibrated by using absolute dipole moment values drawn from the Geomagia and Pint paleointensity value databases. The 10Be-derived geomagnetic dipole moment record, independent from sedimentary paleomagnetic data, covers the Brunhes-Matuyama transition and the whole Brunhes Chron. It provides new and complementary data on the amplitude and timing of millennial-scale geomagnetic dipole moment variations and particularly on dipole moment collapses triggering polarity instabilities.

  6. High-precision Penning trap mass measurements of 9,10Be and the one-neutron halo nuclide 11Be

    NASA Astrophysics Data System (ADS)

    Ringle, R.; Brodeur, M.; Brunner, T.; Ettenauer, S.; Smith, M.; Lapierre, A.; Ryjkov, V. L.; Delheij, P.; Drake, G. W. F.; Lassen, J.; Lunney, D.; Dilling, J.

    2009-05-01

    Penning trap mass measurements of 9Be, 10Be (t1 / 2 = 1.51 My), and the one-neutron halo nuclide 11Be (t1 / 2 = 13.8 s) have been performed using TITAN at TRIUMF. The resulting 11Be mass excess (ME = 20 177.60 (58) keV) is in agreement with the current Atomic Mass Evaluation (AME03) [G. Audi, et al., Nucl. Phys. A 729 (2003) 337] value, but is over an order of magnitude more precise. The precision of the mass values of 9,10Be have been improved by about a factor of four and reveal a ≈ 2 σ deviation from the AME mass values. Results of new atomic physics calculations are presented for the isotope shift of 11Be relative to 9Be, and it is shown that the new mass values essentially remove atomic mass uncertainties as a contributing factor in determining the relative nuclear charge radius from the isotope shift. The new mass values of 10,11Be also allow for a more precise determination of the single-neutron binding energy of the halo neutron in 11Be.

  7. Long-term rates of chemical weathering and physical erosion in extreme climates, measured by cosmogenic nuclides and geochemical mass balance

    NASA Astrophysics Data System (ADS)

    Riebe, C. S.; Kirchner, J. W.; Finkel, R. C.

    2001-12-01

    Chemical weathering and physical erosion jointly regulate soil development and deliver sediment and solutes to riverine habitats. Chemical weathering also generates nutrients and helps regulate global climate over million year timescales. Thus it is important to quantify long-term rates of weathering and erosion in different environments. New cosmogenic nuclide and geochemical mass balance techniques can be widely applied to measure long-term rates of chemical weathering and physical erosion. In previous work, we used those techniques to show that both physical erosion and chemical weathering rates are insensitive to differences in climate across a set of granitic Sierra Nevada study sites that span 20-145 cm/yr in average precipitation and 4-15 ° C in mean annual temperature. Our measurements also showed that long-term rates of chemical weathering and physical erosion are tightly coupled, possibly because chemical weathering rates are regulated by rates of fresh mineral supply by physical erosion of rock. Here we present long-term rates of chemical weathering and physical erosion from new sites with more extreme climates, including both temperate and tropical rainforests. Overall, mean annual temperature spans 4-22 ° C and average precipitation span 20-420 cm/yr across our sites. Our new weathering and erosion data should reveal whether climatic effects on rates of weathering and erosion are more pronounced over a greatly extended range of climates.

  8. Measuring the Retreat Velocity of the Laurentide Ice Sheet by Cosmogenic Nuclides? Be-10 Dating of Glacial Features in Lower Hudson Valley

    NASA Astrophysics Data System (ADS)

    Steinberg, R.; Kelly, M.; Schaefer, J. M.; Rinterknecht, V.; Schwartz, R.; Balco, G.

    2005-12-01

    The Laurentide Ice Sheet (LIS) was the earth's dominant continental ice sheet during the Last Glacial Maximum (LGM). The LIS deglaciation represents a dramatic environmental change that released enormous amounts of fresh water to the Atlantic Ocean, potentially inhibiting the North Atlantic Deep Water formation, thus affecting the thermohaline ocean circulation and global climate. To evaluate the impact of this fresh-water signal, it is important to determine the timing and rate of the LIS retreat, particularly along the Eastern margin of the United States. Glacial geologic features in the Lower Hudson Valley region provide evidence of the advance of LIS to its LGM terminus at Long Island and the subsequent ice recession. The surface exposure dating method using the cosmogenic nuclide Be-10 is applied to date glacially transported erratic boulders and scoured bedrock in two areas, Black Rock Forest and Harriman State Park, in the Lower Hudson Valley. We compare these Be-10 dates with numerous Be-10 dates from the terminal moraine on Long Island (Harbor Hill Moraine) and its extension in Connecticut (Charlestown Moraine). The goal of this project is to develop a chronology of the recessional ice margin. A comparison of Be-10 dates from the terminal moraine at Long Island with those located in the Lower Hudson Valley region yields a first order measure of the rate of the LIS retreat.

  9. The behavior of the uranium decay chain nuclides and thorium during the flank eruptions of Kilauea (Hawaii) between 1983 and 1985

    SciTech Connect

    Reinitz, I.M.; Turekian, K.K. )

    1991-12-01

    The concentrations of members of the {sup 238}U decay chain and {sup 232}Th have been determined for the lavas that erupted on the East Rift Zone of Kilauea Volcano, Hawaii (Puu Oo) between January 1983 and January 1985. There was a decrease during the first 180 days in the abundances of all nuclides, following the behavior of the incompatible elements. ({sup 230}Th/{sup 238}U) varies with ({sup 232}Th/{sup 238}U) yielding a batch process age for the source magma of 127,800 {plus minus} 28,500 (2{omega}) y, similar to East Pacific Rise basalts. No ({sup 226}Ra/{sup 230}Th) disequilibrium was evident at Puu Oo although Haleakala and Loihi show significant excesses of ({sup 226}Ra) over ({sup 230}Th). The initial ({sup 210}Pb) excess relative to ({sup 226}Ra) implies strong incompatibility of {sup 210}Pb probably with the help of chloride complexing, and the deficiency in later episodes indicates volatilization from the melt mediated by the formation of volatile chloride compounds.

  10. Uranium, radium and thorium in soils with high-resolution gamma spectroscopy, MCNP-generated efficiencies, and VRF non-linear full-spectrum nuclide shape fitting

    NASA Astrophysics Data System (ADS)

    Metzger, Robert; Riper, Kenneth Van; Lasche, George

    2017-09-01

    A new method for analysis of uranium and radium in soils by gamma spectroscopy has been developed using VRF ("Visual RobFit") which, unlike traditional peak-search techniques, fits full-spectrum nuclide shapes with non-linear least-squares minimization of the chi-squared statistic. Gamma efficiency curves were developed for a 500 mL Marinelli beaker geometry as a function of soil density using MCNP. Collected spectra were then analyzed using the MCNP-generated efficiency curves and VRF to deconvolute the 90 keV peak complex of uranium and obtain 238U and 235U activities. 226Ra activity was determined either from the radon daughters if the equilibrium status is known, or directly from the deconvoluted 186 keV line. 228Ra values were determined from the 228Ac daughter activity. The method was validated by analysis of radium, thorium and uranium soil standards and by inter-comparison with other methods for radium in soils. The method allows for a rapid determination of whether a sample has been impacted by a man-made activity by comparison of the uranium and radium concentrations to those that would be expected from a natural equilibrium state.

  11. The Neutrino Energy Loss of Nuclides by K-shell Continuum State Electron Capture at the Late Stage of Stellar Evolution

    NASA Astrophysics Data System (ADS)

    Liu, J. J.; Lin, Y.

    2013-01-01

    Based on the Weinberg-Salam theory and taken into consideration of the Coulomb effect on electron gas, the neutrino energy loss rates by K-shell continuum state electron capture are discussed for ^{12}C, ^{16}O, ^{20}Ne, ^{24}Mg, ^{28}Si and ^{56}Fe under the condition of complete ionization and at the late stage of stellar evolution. Our results are compared with those of Beaudet, Petrosian and Salpeter (BPS). It is shown that at relatively high temperatures (e.g., {T_9 = 0.1} and {T_9 = 1}, T_9 represents the temperature in units of 10^9 K), our results agree well with BPS's. However, at relatively low temperatures (e.g., {T_9 = 0.01} and {T_9 = 0.001}), the neutrino energy loss rates of BPS for ^{16}O, ^{20}Ne, ^{24}Mg and ^{28}Si are higher than our results by 10˜ 70 times, and even by 2 orders of magnitude for nuclide ^{12}C. Our results may be of great importance in the research of late stellar evolution, especially for the cooling mechanism of white dwarf, during which the nucleus collapsed to the stage with a relatively low temperature and intermediate density.

  12. Decay properties of double heavy baryons

    SciTech Connect

    Faessler, Amand; Gutsche, Thomas; Lyubovitskij, Valery; Ivanov, Mikhail A.; Koerner, Juergen G.

    2010-08-05

    We study the semileptonic decays of double heavy baryons using a manifestly Lorentz covariant constituent three-quark model. We present complete results on transition form factors between double-heavy baryons for finite values of the heavy quark/baryon masses and in the heavy quark symmetry limit which is valid at and close to zero recoil. Decay rates are calculated and compared to each other in the full theory, keeping masses finite, and also in the heavy quark limit.

  13. Heavy Pentaquarks and Doubly Heavy Baryons in Quasiparticle Approach

    NASA Astrophysics Data System (ADS)

    Chandra, A.; Bhattacharya, A.; Chakrabarti, B.

    In the framework of the quasiparticle approach, the ground state mass of heavy pentaquarks have been investigated in diquark-diquark-antiquark picture and the higher states are investigated in the mass loaded flux tube model where two light diquarks are supposed to be linked by a flux tube to the heavy quark. The Regge trajectories for heavy pentaquarks have been studied. The Regge slope (α) of these particles have been obtained as ≈1 GeV2 which indicates that the Regge trajectory follows the linearity conditions with universal value of α ( 1 GeV2). The ground state mass of doubly charm and doubly bottom baryons like Ξ cc++, Ξ bb0, Ω cc+, Ω bb- have also been investigated in quasiparticle approach. The results are found to be in reasonably good agreement with the experimental and other theoretical estimates.

  14. Heavy quarkonium photoproduction in ultrarelativistic heavy ion collisions

    NASA Astrophysics Data System (ADS)

    Yu, Gong-Ming; Cai, Yang-Bing; Li, Yun-De; Wang, Jian-Song

    2017-01-01

    Based on the factorization formalism of nonrelativistic quantum chromodynamics (NRQCD), we calculate the production cross section for the charmonium [J /ψ , ψ (2 S ) , χc J, ηc, and hc] and the bottomonium [Υ (n S ) , χb J, ηb, and hb] produced by the hard photoproduction processes and fragmentation processes in relativistic heavy ion collisions. It is shown that the existing experimental data on heavy quarkonium production at the Large Hadron Collider (LHC) can be described in the framework of the NRQCD formalism, and the phenomenological values of matrix elements for color-singlet and color-octet components give the main contribution. The numerical results of photoproduction processes and fragmentation processes for the heavy quarkonium production become prominent in p -p collisions and Pb-Pb collisions at LHC energies.

  15. Swift Heavy Ions in Matter

    NASA Astrophysics Data System (ADS)

    Rothard, Hermann; Severin, Daniel; Trautmann, Christina

    2015-12-01

    The present volume contains the proceedings of the Ninth International Symposium on Swift Heavy Ions in Matter (SHIM). This conference was held in Darmstadt, from 18 to 21 May 2015. SHIM is a triennial series, which started about 25 years ago by a joint initiative of CIRIL - Caen and GSI - Darmstadt, with the aim of promoting fundamental and applied interdisciplinary research in the field of high-energy, heavy-ion interaction processes with matter. SHIM was successively organized in Caen (1989), Bensheim (1992), Caen (1995), Berlin (1998), Catania (2002), Aschaffenburg (2005), Lyon (2008), and Kyoto (2012). The conference attracts scientists from many different fields using high-energy heavy ions delivered by large accelerator facilities and characterized by strong and short electronic excitations.

  16. Heavy ion collisions and cosmology

    NASA Astrophysics Data System (ADS)

    Floerchinger, Stefan

    2016-12-01

    There are interesting parallels between the physics of heavy ion collisions and cosmology. Both systems are out-of-equilibrium and relativistic fluid dynamics plays an important role for their theoretical description. From a comparison one can draw interesting conclusions for both sides. For heavy ion physics it could be rewarding to attempt a theoretical description of fluid perturbations similar to cosmological perturbation theory. In the context of late time cosmology, it could be interesting to study dissipative properties such as shear and bulk viscosity and corresponding relaxation times in more detail. Knowledge and experience from heavy ion physics could help to constrain the microscopic properties of dark matter from observational knowledge of the cosmological fluid properties.

  17. Accelerators for heavy ion fusion

    SciTech Connect

    Bangerter, R.O.

    1985-10-01

    Large fusion devices will almost certainly produce net energy. However, a successful commercial fusion energy system must also satisfy important engineering and economic constraints. Inertial confinement fusion power plants driven by multi-stage, heavy-ion accelerators appear capable of meeting these constraints. The reasons behind this promising outlook for heavy-ion fusion are given in this report. This report is based on the transcript of a talk presented at the Symposium on Lasers and Particle Beams for Fusion and Strategic Defense at the University of Rochester on April 17-19, 1985.

  18. Relativistic heavy ion facilities: worldwide

    SciTech Connect

    Schroeder, L.S.

    1986-05-01

    A review of relativistic heavy ion facilities which exist, are in a construction phase, or are on the drawing boards as proposals is presented. These facilities span the energy range from fixed target machines in the 1 to 2 GeV/nucleon regime, up to heavy ion colliders of 100 GeV/nucleon on 100 GeV/nucleon. In addition to specifying the general features of such machines, an outline of the central physics themes to be carried out at these facilities is given, along with a sampling of the detectors which will be used to extract the physics. 22 refs., 17 figs., 3 tabs.

  19. Open Heavy Flavor Measurements in Heavy Ion Collisions with CMS

    NASA Astrophysics Data System (ADS)

    Sun, Jian

    2016-12-01

    The measurement of heavy flavor production is a powerful tool to study the properties of the high-density QCD medium created in heavy-ion collisions as heavy quarks are sensitive to the transport properties of the medium and may interact with the matter differently than light quarks. Heavy flavor jets, non-prompt J / ψ (J / ψ from B-hadron decay) and fully reconstructed B mesons have been studied in PbPb collisions at 2.76 TeV and pPb collisions at 5.02 TeV with CMS. Recently, the nuclear modification factor of prompt D0 mesons has been measured in PbPb collisions at 2.76 TeV with CMS as a function of both transverse momentum and collision centrality. These studies show that prompt D0 production is suppressed in semi-central to central PbPb collisions and the suppression is smaller at high pT. A comparison with the RAA of charged particle and non-prompt J / ψ hints a hierarchy of suppression as a function of flavor.

  20. Gamma-ray characterization of uranium-series nuclides and its application to the study of the Pena Blanca natural analogue site, Chihuahua, Mexico

    NASA Astrophysics Data System (ADS)

    Wong, Virgina

    Two natural analogue sites located in the Pena Blanca Uranium District, Chihuahua, Mexico were characterized for radionuclide mobility. Analogue I is used to assess the long-term behavior of uranium-series nuclides in a host rock and geochemical environment that is similar to the proposed high-level waste repository at Yucca Mountain, Nevada. Analogue II represents a former dump site to assess short-term radionuclide mobility. Gamma-ray spectroscopy analysis was used to measure radioactivity of the U-series nuclides. Samples analyzed from Analogue I consist of: (1) fracture-infillings associated with different alteration assemblages collected within and outside the breccia pipe from various levels of the deposit and (2) fracture-infillings collected along an east-west trending fracture which intersects the breccia pipe and extends into the host rock. Alteration mineralogy, established via X-ray diffraction analysis, consists of pure kaolinite, a mixture of Fe-oxyhydroxide (goethite, hematite) With inclusions of jarosite and alunite, and carbonates. Results from activity ratios of 230Th/238U versus 226Ra/230Th indicate that majority of the Fe-oxyhydroxides from the breccia zone show a slight disequilibrium with respect to Ra enrichment and U depletion. This observation is modeled as requiring a multiple-event history of U mobility. An amorphous Fe sample distal to the breccia zone shows similar behavior but to a greater extent. This extreme behavior is ascribed to initially low U content and greater late-stage U removal. Two Fe-oxyhydroxide samples from Within the breccia pipe also display multiple-event stages but exhibit both Ra and U leaching. This behavior is shared by Fe-oxyhydroxide samples collected inside and peripheral to the breccia zone from the east-west trending fracture. Finally, three samples, two Fe phase samples outside the breccia zone and a kaolinite inside the breccia zone, show Ra and U enrichment. Also, a distal Fe-oxyhydroxide sample from the

  1. No chance for synthesis of super-heavy nuclei in fusion of symmetric systems

    NASA Astrophysics Data System (ADS)

    Cap, T.; Siwek-Wilczyńska, K.; Wilczyński, J.

    2014-09-01

    Predictions of relatively large cross sections (of about 1 picobarn) for synthesis of super heavy nuclei of Z=122 and Z=124 in cold fusion (1n) reactions of symmetric 154Sm + 150Nd and 154Sm + 154Sm systems by R.K. Choudhury and Y.K. Gupta (2014) [1] are examined. The authors state that this result had been obtained by using the fusion-by-diffusion (FBD) model. As predictions of the original FBD model of Swiatecki, Cap, Siwek-Wilczyńska and Wilczyński had been definitely pessimistic regarding fusion of more symmetric systems (in comparison with equivalent asymmetric systems), we feel compelled to present excitation functions of the 154Sm(150Nd, 1n)303122 and 154Sm(154Sm, 1n)307124 reactions, calculated within the original fusion-by-diffusion model. In accordance with our earlier predictions of a general trend of fusion hindrance for near-symmetric systems, the cross sections for synthesis of 303122 and 307124 nuclides in fusion of these two symmetric systems are found to be extremely small and probably never reachable: about 10-11 pb and 10-13 pb, respectively. It is shown that Choudhury and Gupta obtained their results (overestimating the cross sections by 11 and 13 orders of magnitude) as an effect of an arbitrary and physically unjustified interference in the FBD model.

  2. Authigenic (10)Be/(9)Be ratio signatures of the cosmogenic nuclide production linked to geomagnetic dipole moment variation since the Brunhes/Matuyama boundary.

    PubMed

    Simon, Quentin; Thouveny, Nicolas; Bourlès, Didier L; Valet, Jean-Pierre; Bassinot, Franck; Ménabréaz, Lucie; Guillou, Valéry; Choy, Sandrine; Beaufort, Luc

    2016-11-01

    Geomagnetic dipole moment variations associated with polarity reversals and excursions are expressed by large changes of the cosmogenic nuclide beryllium-10 ((10)Be) production rates. Authigenic (10)Be/(9)Be ratios (proxy of atmospheric (10)Be production) from oceanic cores therefore complete the classical information derived from relative paleointensity (RPI) records. This study presents new authigenic (10)Be/(9)Be ratio results obtained from cores MD05-2920 and MD05-2930 collected in the west equatorial Pacific Ocean. Be ratios from cores MD05-2920, MD05-2930 and MD90-0961 have been stacked and averaged. Variations of the authigenic (10)Be/(9)Be ratio are analyzed and compared with the geomagnetic dipole low series reported from global RPI stacks. The largest (10)Be overproduction episodes are related to dipole field collapses (below a threshold of 2 × 10(22) Am(2)) associated with the Brunhes/Matuyama reversal, the Laschamp (41 ka) excursion, and the Iceland Basin event (190 ka). Other significant (10)Be production peaks are correlated to geomagnetic excursions reported in literature. The record was then calibrated by using absolute dipole moment values drawn from the Geomagia and Pint paleointensity value databases. The (10)Be-derived geomagnetic dipole moment record, independent from sedimentary paleomagnetic data, covers the Brunhes-Matuyama transition and the whole Brunhes Chron. It provides new and complementary data on the amplitude and timing of millennial-scale geomagnetic dipole moment variations and particularly on dipole moment collapses triggering polarity instabilities.

  3. Modelling Deposition and Erosion rates with RadioNuclides (MODERN) - Part 1: A new conversion model to derive soil redistribution rates from inventories of fallout radionuclides.

    PubMed

    Arata, Laura; Meusburger, Katrin; Frenkel, Elena; A'Campo-Neuen, Annette; Iurian, Andra-Rada; Ketterer, Michael E; Mabit, Lionel; Alewell, Christine

    2016-10-01

    The measurement of fallout radionuclides (FRN) has become one of the most commonly used tools to quantify sediment erosion or depositional processes. The conversion of FRN inventories into soil erosion and deposition rates is done with a variety of models, which suitability is dependent on the selected FRN, soil cultivation (ploughed or unploughed) and movement (erosion or deposition). The authors propose a new conversion model, which can be easily and comprehensively used for different FRN, land uses and soil redistribution processes. The new model MODERN (Modelling Deposition and Erosion rates with RadioNuclides) considers the precise depth distribution of any FRN at the reference site, and allows adapting it for any specific site conditions. MODERN adaptability and performance in converting different FRN inventories is discussed for a theoretical case as well as for two already published case studies i.e. a (137)Cs study in an alpine and unploughed area in the Aosta valley (Italy) and a (210)Pbex study on a ploughed area located in the Transylvanian Plain (Romania). The tests highlight a highly significant correspondence (i.e. correlation factor of 0.91) between the results of MODERN and the published results of other models currently used by the FRN scientific community (i.e. the Profile Distribution Model and the Mass Balance Model). The development and the cost free accessibility of MODERN (see modern.umweltgeo.unibas.ch) will ensure the promotion of wider application of FRNs for tracing soil erosion and sedimentation. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  4. Authigenic 10Be/9Be ratio signatures of the cosmogenic nuclide production linked to geomagnetic dipole moment variation since the Brunhes/Matuyama boundary

    PubMed Central

    Thouveny, Nicolas; Bourlès, Didier L.; Valet, Jean‐Pierre; Bassinot, Franck; Ménabréaz, Lucie; Guillou, Valéry; Choy, Sandrine; Beaufort, Luc

    2016-01-01

    Abstract Geomagnetic dipole moment variations associated with polarity reversals and excursions are expressed by large changes of the cosmogenic nuclide beryllium‐10 (10Be) production rates. Authigenic 10Be/9Be ratios (proxy of atmospheric 10Be production) from oceanic cores therefore complete the classical information derived from relative paleointensity (RPI) records. This study presents new authigenic 10Be/9Be ratio results obtained from cores MD05‐2920 and MD05‐2930 collected in the west equatorial Pacific Ocean. Be ratios from cores MD05‐2920, MD05‐2930 and MD90‐0961 have been stacked and averaged. Variations of the authigenic 10Be/9Be ratio are analyzed and compared with the geomagnetic dipole low series reported from global RPI stacks. The largest 10Be overproduction episodes are related to dipole field collapses (below a threshold of 2 × 1022 Am2) associated with the Brunhes/Matuyama reversal, the Laschamp (41 ka) excursion, and the Iceland Basin event (190 ka). Other significant 10Be production peaks are correlated to geomagnetic excursions reported in literature. The record was then calibrated by using absolute dipole moment values drawn from the Geomagia and Pint paleointensity value databases. The 10Be‐derived geomagnetic dipole moment record, independent from sedimentary paleomagnetic data, covers the Brunhes‐Matuyama transition and the whole Brunhes Chron. It provides new and complementary data on the amplitude and timing of millennial‐scale geomagnetic dipole moment variations and particularly on dipole moment collapses triggering polarity instabilities. PMID:28163989

  5. The influence of religious affiliation on heavy drinking, heavy smoking and heavy betel nut chewing.

    PubMed

    Chen, Chiang-Ming

    2014-01-01

    The results of a national survey of determinants of drinking, smoking and betel-nut chewing behaviors are analyzed. The purpose of this paper is to empirically investigate whether drinking, smoking and betel-nut chewing are influenced by a variety of religions based on Taiwan data. Our results suggest that Buddhism, Taoism and practitioners of Chinese folk region are positively associated with heavy betel nut chewing while the religion effects on heavy smoking and drinking are statistically insignificant. Our findings on religion effects in Taiwan can be a valuable reference for comparison in Christian and western countries.

  6. Heavy ions in Jupiter's environment

    NASA Technical Reports Server (NTRS)

    Brown, R. A.

    1980-01-01

    The extended atmosphere of the Jupiter system consists of atoms and ions of heavy elements. This material originates on the satellite Io. Energy is lost from the thermal plasma in collisionally excited optical and ultraviolet emission. The juxtaposition of Earth and spacecraft measurements provide insight concerning the underlying processes of particle transport and energy supply.

  7. The Search for Heavy Elements

    ScienceCinema

    None

    2016-07-12

    The 1994 documentary "The Search for Heavy Elements" chronicles the expansion of the periodic table through the creation at Berkeley Lab of elements heavier than uranium. The documentary features a mix of rarely-seen archival footage, historical photos, and interviews with scientists who made history, such as Glenn Seaborg and Albert Ghiorso.

  8. 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.)

  9. Heavy quark physics from LEP

    SciTech Connect

    Dornan, P.J.

    1997-01-01

    A review of some of the latest results on heavy flavor physics from the LEP Collaborations is presented. The emphasis is on B physics, particularly new results and those where discrepancies is given of the many techniques which have been developed to permit these analyses.

  10. Prosthetic Hand Lifts Heavy Loads

    NASA Technical Reports Server (NTRS)

    Carden, James R.; Norton, William; Belcher, Jewell G.; Vest, Thomas W.

    1991-01-01

    Prosthetic hand designed to enable amputee to lift diverse heavy objects like rocks and logs. Has simple serrated end effector with no moving parts. Prosthesis held on forearm by system of flexible straps. Features include ruggedness, simplicity, and relatively low cost.

  11. Heavy Quark Photoproduction at LHC

    NASA Astrophysics Data System (ADS)

    Gonçalves, V. P.; Meneses, A. R.; Machado, M. V.

    2010-11-01

    In this work we calculate the inclusive and difractive photoproduction of heavy quarks in proton-proton collisions at LHC energies within the color dipole picture employing three phenomenological saturation models based on the color glass condensate formalism. Our results demonstrate that the experimental analyzes of these reactions is feasible and that the cross sections are sensitive to the underlying parton dynamics.

  12. Heavy Flavour Production at HERA

    NASA Astrophysics Data System (ADS)

    Plačakytė, Ringailė; H1; Zeus Collaborations

    2014-11-01

    Measurements of open charm and beauty production at HERA provide important input for stringent tests of quantum chromodynamics and are used to constrain the parton distribution functions of the proton. The recent results on the heavy flavour production obtained by the H1 and ZEUS experiments at HERA are reviewed in this contribution.

  13. Heavy flavour production at HERA

    NASA Astrophysics Data System (ADS)

    Brugnera, Riccardo

    2014-11-01

    In this brief review, recent experimental results from the H1 and ZEUS collaborations on heavy flavour production in deep inelastic scattering and photoproduction regimes are summarized. The results cover charm fragmentation fractions, charm and beauty cross sections, F2cc¯ and F2bb¯ proton structure functions and the running charm- and beauty-quark masses.

  14. Heavy-quark QCD exotica

    NASA Astrophysics Data System (ADS)

    Lebed, Richard F.; Mitchell, Ryan E.; Swanson, Eric S.

    2017-03-01

    This review presents an overview of the remarkable progress in the field of heavy-quark exotic hadrons over the past 15 years. It seeks to be pedagogical rather than exhaustive, summarizing both the progress and specific results of experimental discoveries, and the variety of theoretical approaches designed to explain these new states.

  15. Prosthetic Hand Lifts Heavy Loads

    NASA Technical Reports Server (NTRS)

    Carden, James R.; Norton, William; Belcher, Jewell G.; Vest, Thomas W.

    1991-01-01

    Prosthetic hand designed to enable amputee to lift diverse heavy objects like rocks and logs. Has simple serrated end effector with no moving parts. Prosthesis held on forearm by system of flexible straps. Features include ruggedness, simplicity, and relatively low cost.

  16. The Search for Heavy Elements

    SciTech Connect

    2008-04-17

    The 1994 documentary "The Search for Heavy Elements" chronicles the expansion of the periodic table through the creation at Berkeley Lab of elements heavier than uranium. The documentary features a mix of rarely-seen archival footage, historical photos, and interviews with scientists who made history, such as Glenn Seaborg and Albert Ghiorso.

  17. Heavy particle radiotherapy: prospects and pitfalls

    SciTech Connect

    Faju, M.R.

    1980-01-01

    The use of heavy particles in radiotherapy of tumor volumes is examined. Particles considered are protons, helium ions, heavy ions, negative pions, and fast neutrons. Advantages and disadvantages are discussed. (ACR)

  18. Abatement of Marine Coatings Containing Heavy Metals

    DTIC Science & Technology

    1995-06-01

    in the abatement of heavy metal containing marine coatings. Funding for this...shipyards to be proactive in the area of heavy metal coating systems abatement as current regulations were not "user friendly" in shipboard applications.

  19. Heavy metals and coal combustion

    SciTech Connect

    Danihelka, P.; Ochodek, T.; Noskievic, P.; Seidlerova, J.

    1998-07-01

    Combustion of coal may be an important source of heavy metals pollution. The distribution of heavy metals during combustion process has been studied in six power plants, where fuel, bottom ash, fly ash and emissions have been analyzed and the relative concentrations of heavy metals have been estimated. For the most volatile metals (arsenic, antimony, lead, and zinc), the redistribution process involving condensation on surface is probable. Some metals like manganese or chromium are concentrated rather in coarse particles. In such cases, no clear conclusion can be made and probably several mechanisms are involved, including mineral form of metal. Typical results of low chlorine coal (0.01--0.03% Cl) exhibit increasing concentration of volatile metals in the magnitude of around one order when going from bottom ash to emissions. Different results have been found in similar operation conditions in the case of high content of chlorine in coal (0.3% of Cl in coal). In this case, the concentration of metals in emissions is significantly higher and also nickel, copper and manganese concentrations increase. It seems to be probable that chlorine in the coal increases the redistribution of metals by volatile chlorides formation. At three operation condition (nominal output, 70% and 40% respectively) emission factors of heavy metals have been estimated for 35 MW stoker-fired boiler. Ba, Pb, Sb and Zn increased their emission factors and Cr and Mn decreased when output was decreased. Heavy metals pollution caused by emissions from combustion of coal may be decreased by fine particles removal, other possibilities (metals extraction from the coal, changes of condition in the flame) are rather limited.

  20. Neutron-rich rare-isotope production from projectile fission of heavy nuclei near 20 MeV/nucleon beam energy

    NASA Astrophysics Data System (ADS)

    Vonta, N.; Souliotis, G. A.; Loveland, W.; Kwon, Y. K.; Tshoo, K.; Jeong, S. C.; Veselsky, M.; Bonasera, A.; Botvina, A.

    2016-12-01

    We investigate the possibilities of producing neutron-rich nuclides in projectile fission of heavy beams in the energy range of 20 MeV/nucleon expected from low-energy facilities. We report our efforts to theoretically describe the reaction mechanism of projectile fission following a multinucleon transfer collision at this energy range. Our calculations are mainly based on a two-step approach: The dynamical stage of the collision is described with either the phenomenological deep-inelastic transfer model (DIT) or with the microscopic constrained molecular dynamics model (CoMD). The de-excitation or fission of the hot heavy projectile fragments is performed with the statistical multifragmentation model (SMM). We compared our model calculations with our previous experimental projectile-fission data of 238U (20 MeV/nucleon) + 208Pb and 197Au (20 MeV/nucleon) + 197Au and found an overall reasonable agreement. Our study suggests that projectile fission following peripheral heavy-ion collisions at this energy range offers an effective route to access very neutron-rich rare isotopes toward and beyond the astrophysical r-process path.

  1. ``Heavy-water Lattice and Heavy-Quark''

    NASA Astrophysics Data System (ADS)

    Maksoed, Ssi, Wh-

    Refer to Birgitt Roettger-Roessler: ``Feelings at the Margins'', 2014 retrieved the Vienna, 2006 UNIDO Research Programme: Combating Marginalization and Poverty through Industrial Development/COMPID. Also from Vienna, on Feb 18-22, 1963 reported Technical Report Series 20 about ``Heavy Water Lattice''. Failed to relates scale-invariant properties of public-Debt growth to convergence in perturbation theory, sought JH Field: ``Convergence & Gauge Dependence Properties:..''. Furthers, in GP Lepage: ``On the Viabilities of Lattice Perturbation Theory'', 1992 stated: ``in terms of physical quantities, like the heavy-quark potential, greatly enhanced the predictive power of lattice perturbation theory''. Acknowledgements to HE. Mr. H. TUK SETYOHADI, Jl. Sriwijaya Raya 3, South-Jakarta, INDONESIA.

  2. Heavy-heavy-light-light correlators in Liouville theory

    NASA Astrophysics Data System (ADS)

    Balasubramanian, V.; Bernamonti, A.; Craps, B.; De Jonckheere, T.; Galli, F.

    2017-08-01

    We compute four-point functions of two heavy and two "perturbatively heavy" operators in the semiclassical limit of Liouville theory on the sphere. We obtain these "Heavy-Heavy-Light-Light" (HHLL) correlators to leading order in the conformal weights of the light insertions in two ways: (a) via a path integral approach, combining different methods to evaluate correlation functions from complex solutions for the Liouville field, and (b) via the conformal block expansion. This latter approach identifies an integral over the continuum of normalizable states and a sum over an infinite tower of lighter discrete states, whose contribution we extract by analytically continuing standard results to our HHLL setting. The sum over this tower reproduces the sum over those complex saddlepoints of the path integral that contribute to the correlator. Our path integral computations reveal that when the two light operators are inserted at equal time in radial quantization, the leading-order HHLL correlator is independent of their separation, and more generally that at this order there is no short-distance singularity as the two light operators approach each other. The conformal block expansion likewise shows that in the discrete sum short-distance singularities are indeed absent for all intermediate states that contribute. In particular, the Virasoro vacuum block, which would have been singular at short distances, is not exchanged. The separation-independence of equal-time correlators is due to cancelations between the discrete contributions. These features lead to a Lorentzian singularity that, in conformal theories with anti-de Sitter (AdS) duals, would be associated to locality below the AdS scale.

  3. Heavy Baryons:. a Combined Large Nc and Heavy Quark Expansion for Electroweak Currents

    NASA Astrophysics Data System (ADS)

    Gelman, Boris A.

    2002-09-01

    The combined large Nc and heavy quark limit for baryons containing a single heavy quark is discussed. The combined large Nc and heavy quark expansion of the heavy quark bilinear operators is obtained. In this expansion, the corrections proportional to mN/mQ are summed to all orders. In particular, the expansion can be used to determine semileptonic form factors of heavy baryons in the combined limit.

  4. Nuclide-migration field experiments

    SciTech Connect

    Erdal, B.R.; Wolfsberg, K.; Johnstone, J.K.; Erickson, K.L.; Friedman, A.M.; Fried, S.; Hines, J.J.

    1981-03-01

    When considering groundwater flow and radionuclide retention in the complex flow systems that can occur in geologic formations, one has a serious problem in determining if laboratory studies are being performed under conditions appropriate to natural systems. This document is the project plan for a program designed to begin to address these problems. The project is being carried out jointly by the Los Alamos National Laboratory, Sandia National Laboratories, and Argonne National Laboratory. The work has three principal objectives: (1) to develop the experimental, instrumental, and safety techniques necessary to conduct controlled, small-scale radionuclide migration field experiments, including those involving actinides; (2) to use these techniques to define radionuclide migration through rock by performing generic, at-depth experiments under closely monitored conditions; and (3) to determine whether available lithologic, geochemical, and hydrologic properties together with existing or developing transport models are sufficient and appropriate to describe real field conditions.

  5. Heavy flavor production from photons and hadrons

    SciTech Connect

    Heusch, C.A.

    1982-01-01

    The present state of the production and observation of hadrons containing heavy quarks or antiquarks as valence constituents, in reactions initiated by real and (space-like) virtual photon or by hadron beams is discussed. Heavy flavor production in e/sup +/e/sup -/ annihilation, which is well covered in a number of recent review papers is not discussed, and similarly, neutrino production is omitted due to the different (flavor-changing) mechanisms that are involved in those reactions. Heavy flavors from spacelike photons, heavy flavors from real photons, and heavy flavors from hadron-hadron collisions are discussed. (WHK)

  6. [Microbial interactions with heavy metals].

    PubMed

    Cervantes, C; Espino-Saldaña, A E; Acevedo-Aguilar, F; León-Rodriguez, I L; Rivera-Cano, M E; Avila-Rodríguez, M; Wróbel-Kaczmarczyk, K; Wróbel-Zasada, K; Gutiérrez-Corona, J F; Rodríguez-Zavala, J S; Moreno-Sánchez, R

    2006-01-01

    Living organisms are exposed in nature to heavy metals, commonly present in their ionized species. These ions exert diverse toxic effects on microorganisms. Metal exposure both selects and maintains microbial variants able to tolerate their harmful effects. Varied and efficient metal resistance mechanisms have been identified in diverse species of bacteria, fungi and protists. The study of the interactions between microorganisms and metals may be helpful to understand the relations of toxic metals with higher organisms such as mammals and plants. Some microbial systems of metal tolerance have the potential to be used in biotechnological processes, such as the bioremediation of environmental metal pollution or the recovery of valuable metals. In this work we analyze several examples of the interactions of different types of microbes with heavy metals; these cases are related either with basic research or with possible practical applications.

  7. Heavy Metal Pumps in Plants

    SciTech Connect

    Harper, J.F.

    2000-10-01

    The long term goal of the funded research is to understand how heavy metals are taken up from the soil and translocated throughout the plant. The potential application of this research is to create plants with better heavy metal uptake systems and thereby improve the ability of these plants to help clean up toxic metals from soils. A rate limiting step is using plant for bioremediation is the normally poor capacity of plants to concentrate toxic metals. Our interest in metal ion transport systems includes those for essential mineral nutrients such as molybdenum, copper, iron, manganese, as well as toxic metals such as cerium, mercury, cesium, cadmium, arsenic and selenium. Understanding the pathways by which toxic metals accumulate in plants will enable the engineering of plants to exclude toxic metals and create healthier food sources, or to extract toxic metals from the soil as a strategy to clean up polluted lands and water.

  8. Catalytic hydrocracking of heavy oils

    SciTech Connect

    Khulbe, C.P.; Patmore, D.J.; Pruden, B.B.; Ranganathan, R.

    1983-01-25

    An improved process is described for the hydrocracking of heavy hydrocarbon oil, such as oils extracted from tar sands. The charge oil in the presence of an excess of hydrogen is passed through a tubular hydrocracking zone, and the effluent emerging from the top of the zone is separated into a gaseous stream containing a wide boiling range material and a liquid stream containing heavy hydrocarbons. According to the novel feature, the hydrocracking process is carried out in the presence of a catalyst consisting of finely divided coal or other carbonaceous material carrying catalytically active metals from group via and group viii of the periodic table of elements, E.G. Cobalt and molybdenum. The catalyst is slurried with the charge stock and has been found to greatly reduce coke precursors and thereby prevent the formation of carbonaceous deposits in the reaction zone while also being effective in reducing the sulfur concentration of the product.

  9. Semiholography for heavy ion collisions

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, Ayan; Preis, Florian

    2017-03-01

    The formation of QGP in heavy ion collisions gives us a great opportunity for learning about nonperturbative dynamics of QCD. Semiholography provides a new consistent framework to combine perturbative and non-perturbative effects in a coherent way and can be applied to obtain an effective description for heavy ion collisions. In particular, it allows us to include nonperturbative effects in existing glasma effective theory and QCD kinetic theory for the weakly coupled saturated degrees of freedom liberated by the collisions in the initial stages in a consistent manner. We argue why the full framework should be able to confront experiments with only a few phenomenological parameters and present feasibility tests for the necessary numerical computations. Furthermore, we discuss that semiholography leads to a new description of collective flow in the form of a generalised non-Newtonian fluid. We discuss some open questions which we hope to answer in the near future.

  10. Detecting heavy flavors at CBA

    SciTech Connect

    Aronson, S.; Ogilvie, M.; Stumer, I.; Tanaka, M.; Wanderer, P.

    1983-03-01

    In the CBA luminosity range (L approx. = 10/sup 32/-10/sup 33/cm/sup -2/sec/sup -1/) the expected rate of bare heavy flavor production is high enough to allow for detection schemes which rely on relatively small leptonic branching ratios. These provide a clean separation of the signal from the gluon plus light quark background, while retaining sufficient statistics for further study. The current status of the investigation of lepton-related triggers and cuts is presented, and the jet topologies of events (both signal and background) with high-P/sub T/ leptons are discussed. While these studies have been carried out with samples of high-P/sub T/ q anti q and gluon jets generated with ISAJET, other sources of heavy flavor production at CBA are surveyed.

  11. Heavy Vehicle Propulsion Materials Program

    SciTech Connect

    Diamond, S.; Johnson, D.R.

    1999-04-26

    The objective of the Heavy Vehicle Propulsion Materials Program is to develop the enabling materials technology for the clean, high-efficiency diesel truck engines of the future. The development of cleaner, higher-efficiency diesel engines imposes greater mechanical, thermal, and tribological demands on materials of construction. Often the enabling technology for a new engine component is the material from which the part can be made. The Heavy Vehicle Propulsion Materials Program is a partnership between the Department of Energy (DOE), and the diesel engine companies in the United States, materials suppliers, national laboratories, and universities. A comprehensive research and development program has been developed to meet the enabling materials requirements for the diesel engines of the future. Advanced materials, including high-temperature metal alloys, intermetallics, cermets, ceramics, amorphous materials, metal- and ceramic-matrix composites, and coatings, are investigated for critical engine applications.

  12. STAR heavy-ion highlights

    NASA Astrophysics Data System (ADS)

    Rusnakova, Olga

    2016-11-01

    Parton energy loss, quarkonium sequential melting and particle production from electromagnetic interactions are tools to study Quark Gluon Plasma properties. The STAR detector, with large acceptance at mid-rapidity, excellent particle identification and wide transverse momentum coverage, is able to study these probes in details. Di-electron spectra form Beam Energy Scan, measurements of reconstructed jets in Au+Au collisions and quarkonium measurements in p+p and heavy ion collisions are reported in this paper.

  13. Central collisions of heavy ions

    SciTech Connect

    Fung, Sun-yiu.

    1992-10-01

    This report describes the activities of the Heavy Ion Physics Group at the University of California, Riverside from October 1, 1991 to September 30, 1992. During this period, the program focused on particle production at AGS energies, and correlation studies at the Bevalac in nucleus-nucleus central collisions. As part of the PHENIX collaboration, contributions were made to the Preliminary Conceptual Design Report (pCDR), and work on a RHIC silicon microstrip detector R D project was performed.

  14. Heavy ion measurement on LDEF

    NASA Technical Reports Server (NTRS)

    Jonathal, D.; Beaujean, R.; Enge, W.

    1993-01-01

    Heavy ions with nuclear charge Z = 6 to Z = 26 are detected in a stack of plastic track detectors. The measured energies in the range of 10-240 MeV/nuc are well below the geomagnetic cut off value of the Long Duration Exposure Facility (LDEF) orbit. The arrival directions of the low energy particles (Z = 6-26, E less than 40 MeV/nuc) are consistent with a trapped component incident in the South Atlantic Anomaly.

  15. Heavy metals extraction by microemulsions.

    PubMed

    Dantas, T N Castro; Dantas Neto, A A; Moura, M C P A; Barros Neto, E L; Forte, K R; Leite, R H L

    2003-06-01

    The objective of this study is the heavy metal extraction by microemulsion, using regional vegetable oils as surfactants. Firstly, the main parameters, which have influence in the microemulsion region, such as: nature of cosurfactant, influence of cosurfactant (C)/surfactant (S) ratio and salinity were studied, with the objective of choosing the best extraction system. The extraction/reextraction process by microemulsion consists of two stages. In the first one, the heavy metal ion present in the aqueous phase is extracted by the microemulsion. In a second step, the reextraction process occurs: the microemulsion phase, rich in metal, is acidified and the metal is recovered in a new aqueous phase, with higher concentration. The used system had the following parameters: surfactant-saponified coconut oil; cosurfactant-n-butanol; oil phase-kerosene; C/S ratio=4; salinity-2% (NaCl); temperature of 27+/-1 degrees C; water phase-aqueous solution that varied according to the heavy metal in study (Cr, Cu, Fe, Mn, Ni and Pb). A methodology of experimental planning was used (Scheffé Net) to study the behavior of the extraction in a chosen domain. The extraction was accomplished in one step and yielded extraction percentage higher than 98% for all metals. In the reextraction HCl-8M was used as reextraction agent and the influence of the pH and time were verified. This work showed the great efficiency of the microemulsion, indicating that it is possible to extract selectively the heavy metals from the aqueous phase.

  16. Heavy coffee drinking and epilepsy.

    PubMed

    Bonilha, Leonardo; Li, Li M

    2004-06-01

    Dietary habits have been rarely associated with seizure frequency in patients with epilepsy. We report a case of a man with a partial symptomatic epilepsy whose daily habit of heavy coffee drinking was associated with an increased seizure frequency. This patient witnessed a dramatic decrease in the frequency of his seizures after stopping coffee ingestion. Caffeine is a global stimulant and the reduction of its intake may help in the treatment of epilepsy.

  17. The Future of Heavy Lift

    DTIC Science & Technology

    2002-03-01

    Future of Heavy Lift. MAWTS-1 Memo, 2001. Osprey On-Line. Home Page. <http://www.navair.navy.mil/ v22 />. Overarching Commonality Assessment...logistics tails grow. While the MV-22 Osprey will provide this "Over the Horizon" (OTH) capability, it is strictly a medium lift aircraft. It will never...territory. The MV-22 is the Marine Corps’ current answer to implementing OMFTS/STOM from an aviation perspective. 3 The Osprey will eventually

  18. Heavy and Superheavy Atomic Nuclei

    NASA Astrophysics Data System (ADS)

    Sobiczewski, Adam

    2008-10-01

    The appearance and development of the concept of super-heavy atomic nuclei are described. The concept appeared during the studies of the limits of the nuclear chart and of the periodic table of the chemical elements. The article concentrates on theoretical studies of the properties of heaviest nuclei. Results of these studies are illustrated and discussed. Prospects for a nearest future of the research of heaviest nuclei are outlined.

  19. Heavy quark production at CDF

    SciTech Connect

    C. Paus

    2002-11-13

    The contribution summarizes the latest results from CDF on heavy quark production. Results from top, bottom and charm production are included. Some new analysis using Run I (1991-1994) data have become available. More importantly there are a number of results using Run II data which began in April 2001. The data indicate the potential of CDF for bottom and charm production physics in the near future.

  20. Behaviour of nuclides and U-series disequilibrium in clayey sediments: application to the Late Jurassic record from the eastern Paris basin

    NASA Astrophysics Data System (ADS)

    Casanova, J.; Négrel, Ph.; Innocent, C.; Brulhet, J.

    2003-04-01

    We present a record of U-series disequilibrium covering the Callovo-Oxfordian-Thitonian times of the Late Jurassic carbonated platform from the eastern part of the Paris basin. The Callovo-Oxfordian clayey layer is the potential host rock for reconnaissance work carried out by Andra (e.g., Agence Nationale de Gestion des Déchets Radioactifs) in eastern France, the objective of which is the designing and building of an underground research laboratory to study the aptitude of the clay-marl Callovo-Oxfordian layer for the storage of radioactive wastes. We analyse U and Th trace elements on both the labile fraction (extracted by cold HCl) and the total bulk sediments. The Th contents are extremely low in the Oxfordian shelf reef carbonates (<10 ppb) with respect to the Kimmeridgian-Tithonian clayey marls and the Callovian-Oxfordian argilites (up to 10 ppm). In contrast, the uranium contents are much more homogenous (1 ppm ±0.8) along the section. With respect to bulk concentrations, the nuclide contents in the labile component are particularly low in the Callovian-Oxfordian argilites. This behaviour suggests that given the extremely low permeability of the rock, any groundwater circulation of solutes could only have taken place by diffusion - a very slow mechanism that favours water-rock interactions. For U-series analyses (measured by alpha-spectrometry), a total of 43 bulk-rock samples were preferentially microdrilled from the fine-grained lithologies, although the heterogeneity of carbonate facies within sections necessitated occasional sampling of coarser grained lithologies. Within the carbonate-rich part (Oxfordian to Tithonian) of the section, the 234U/238U ratios slightly fluctuate from secular equilibrium and are interpreted as preferential 234U-solution processes related to groundwater circulation. Preferential removal of 234U in this zone is also indicated by some 230Th/234U activity ratios higher than unity. In contrast, most of the samples from the

  1. Toward precise QEC values for the superallowed 0+→0+ β decays of T=2 nuclides: The masses of Na20, Al24, P28, and Cl32

    NASA Astrophysics Data System (ADS)

    Wrede, C.; Clark, J. A.; Deibel, C. M.; Faestermann, T.; Hertenberger, R.; Parikh, A.; Wirth, H.-F.; Bishop, S.; Chen, A. A.; Eppinger, K.; García, A.; Krücken, R.; Lepyoshkina, O.; Rugel, G.; Setoodehnia, K.

    2010-05-01

    High-precision measurements of superallowed 0+→0+ β decays of T=2 nuclides such as Mg20, Si24, S28, and Ar32 can contribute to searches for physics beyond the standard model of particle physics if the QEC values are accurate to a few keV or better. As a step toward providing precise QEC values for these decays, the ground-state masses of the respective daughter nuclei Na20, Al24, P28, and Cl32 have been determined by measuring the (He3,t) reactions leading to them with the Ar36(He3,t)K36 reaction as a calibration. A quadrupole-dipole-dipole-dipole (Q3D) magnetic spectrograph was used together with thin ion-implanted carbon-foil targets of Ne20, Mg24, Si28, S32, and Ar36. The masses of Na20 and Cl32 are found to be in good agreement with the values from the 2003 Atomic Mass Evaluation (AME03) [G. Audi, A. H. Wapstra, and C. Thibault, Nucl. Phys. ANUPABL0375-947410.1016/j.nuclphysa.2003.11.003 729, 337 (2003)], and the precision has been improved by a factor of 6 in both cases. The masses of Al24 and P28 are found to be higher than the values from AME03 by 9.5 keV (3.2σ) and 11.5 keV (3.6σ), respectively, and the precision has been improved by a factor of 2.5 in both cases. The new Cl32 mass is used together with the excitation energy of its lowest T=2 level and the mass of Ar32 to derive an improved superallowed QEC value of 6087.3(22) keV for this case. The effects on quantities related to standard-model tests including the β-ν correlation coefficient a and the isospin-symmetry-breaking correction δC are examined for the A=32 case.

  2. Exhumation and incision history of the Lahul Himalaya, northern India, based on (U-Th)/He thermochronometry and terrestrial cosmogenic nuclide methods

    NASA Astrophysics Data System (ADS)

    Adams, Byron; Dietsch, Craig; Owen, Lewis A.; Caffee, Marc W.; Spotila, James; Haneberg, William C.

    2009-06-01

    Low-temperature apatite (U-Th)/He (AHe) thermochronology on vertical transects of leucogranite stocks and 10Be terrestrial cosmogenic nuclide (TCN) surface exposure dating on strath terraces in the Lahul Himalaya provide a first approximation of long-term (10 4-10 6 years) exhumation rates for the High Himalayan Crystalline Series (HHCS) for northern India. The AHe ages show that exhumation of the HHCS in Lahul from shallow crustal levels to the surface was ~ 1-2 mm/a and occurred during the past ~ 2.5 Ma. Bedrock exhumation in Lahul fits into a regional pattern in the HHCS of low-temperature thermochronometers yielding Plio-Pleistocene ages. Surface exposure ages of strath terraces along the Chandra River range from ~ 3.5 to 0.2 ka. Two sites along the Chandra River show a correlation between TCN age and height above the river level yielding maximum incision rates of 12 and 5.5 mm/a. Comparison of our AHe and surface exposure ages from Lahul with thermochronometry data from the fastest uplifting region at the western end of the Himalaya, the Nanga Parbat syntaxis, illustrates that there are contrasting regions in the High Himalaya where longer term (10 5-10 7 years) erosion and exhumation of bedrock substantially differ even though Holocene rates of fluvial incision are comparable. These data imply that the orogen's indenting corners are regions where focused denudation has been stable since the mid-Pliocene. However, away from these localized areas where there is a potent coupling of tectonic and surface processes that produce rapid uplift and denudation, Plio-Pleistocene erosion and exhumation can be characterized by disequilibrium, where longer term rates are relatively slower and shorter term fluvial erosion is highly variable over time and distance. The surface exposure age data reflect differential incision along the length of the Chandra River over millennial time frames, illustrate the variances that are possible in Himalayan river incision, and highlight

  3. Cirques have growth spurts during deglacial and interglacial periods: Evidence from 10Be and 26Al nuclide inventories in the central and eastern Pyrenees

    NASA Astrophysics Data System (ADS)

    Crest, Y.; Delmas, M.; Braucher, R.; Gunnell, Y.; Calvet, M.

    2017-02-01

    Cirques are emblematic landforms of alpine landscapes. The statistical distribution of cirque-floor elevations is used to infer glacial equilibrium-line altitude, and the age of their frontal moraines for reconstructing glacial chronologies. Very few studies, however, have sought to measure cirque-floor and supraglacial ridgetop bedrock downwearing rates in order to confront these denudation estimates with theoretical models of Quaternary mountain landscape evolution. Here we use 10Be nuclide samples (n = 36) from moraines, bedrock steps, and supraglacial ridgetops among a population of cirques in the east-central Pyrenees in order to quantify denudation in the landscape and detect whether the mountain topography bears any relevance to the glacial buzzsaw hypothesis. Minimum exposure ages (MEAs) obtained for a succession of moraines spanning the Oldest Dryas to the Holocene produced a deglaciation chronology for three different Pyrenean ranges: Maladeta, Bassiès, and Carlit. Based on a series of corrections, calibrations, and chronostratigraphic tuning procedures, MEAs on ice-polished bedrock exposures were further used to model denudation depths at nested timescales during the Würm, the Younger Dryas, and the Holocene. Results show that subglacial cirque-floor denudation was lower during glacial periods (Würm: 10 mm/ka) than during deglacial and interglacial periods (tens to hundreds of mm/ka). The relative inefficiency of glacial denudation in the cirque zone during the Würm would have resulted from (i) cold-based and/or (ii) low-gradient glaciers situated in the upper reaches of the icefield; and/or from (iii) glacier-load starvation because of arrested clast supply from supraglacial rockslopes situated in the permafrost zone. Denudation peaked during the Younger Dryas and Holocene glacial advances, a time when cirque glaciers became steeper, warmer-based, and when frost cracking weakened supraglacial ridgetops, thus enhancing subglacial erosion by providing

  4. [Contrast study on natural radioactive nuclides contents of rice between Xiangshan uranium deposit area, Jiangxi and non-uranium depsoit area].

    PubMed

    Liu, Ping-Hui; Ye, Chang-Sheng; Xie, Shu-Rong; Rui, Yu-Kui

    2009-07-01

    The contents of natural radioactive nuclides such as uranium and thorium in paddies were analyzed and compared by means of ICP-MS. Totally 14 paddy samples were distinguished into two groups and collected from two rice planting area. One group (12 paddy samples) was collected from the Xiangshan uranium deposit area, Jiangxi province; while the other group (2 samples) collected from non-uranium deposit suburban area of Fuzhou city, Jiangxi, as comparison samples. The distance between the two sampling areas is about 80 kilometers. Before analysis, those paddy samples were continuously carbonized by two hours first, then continuously incinerated for 8 hours at the temperature of 600 degrees centigrade. The results show that the uranium contents in the paddy ash of samples gotten from Xiangshan uranium deposit area range from 0.053 to 1.482 microg x g(-1). The uranium contents of two comparison paddy samples ash are 0.059 and 0.061 microg x g(-1), respectiovely. The average uranium content of paddy ash of uranium deposit area is 0.323 microg x g(-1). Compared with the comparison samples, the uranium contents of paddy ash of uranium deposit area are considerably high, 5.30 times that of non-uranium deposit area. The thorium contents in paddy ash of the uranium deposit area, however, are relatively low and less than that of samples collected from non-uranium deposit area, which range from 0.029 to 0.311 microg x g(-1); The average level is 0.104 microg x g(-1), only about 50% of that of paddy ash sampled from non-urnaium deposit area. Moreover, there is significant linearity correlation between uranium and thorium contents of paddy sampled from Xiangshan uranium deposit area. The positive effects show that the thorium contents of paddy increase as uranium contents of paddy in uranium deposit area increase. The causes for the remarkable difference in uranium contents in paddy between urianium deposit area and non-uranium deposit area are not clear yet. The research on

  5. Weathering and denudation rates determined by the combined analysis of Uranium series nuclides and in situ Beryllium in a weathering profile (Vosges massif, Strengbach catchment, France)

    NASA Astrophysics Data System (ADS)

    Ackerer, Julien; Chabaux, François; Van der Woerd, Jerome; Pelt, Eric; Kali, Elise; Pierret, Marie Claire; Viville, Daniel; Wyns, Robert; Negrel, Philippe

    2015-04-01

    The determination of soil sustainability is a major issue for societies. It is crucial to estimate the soil formation and denudation rates to evaluate the landscapes stability and their response to natural or anthropological forcings. In this work, we propose to combine the analysis of Uranium-Thorium-Radium isotopes with the cosmogenic in situ Beryllium in a weathering profile located in the Strengbach catchment to estimate both production rate of regolith and denudation rate of soil and to establish a soil mass balance at millennial timescales. The weathering profile is located on the summit of the watershed and extending from the top soil to the granitic fractured bedrock at 2 m depth. Whole rock data shows different trends of variation of major and trace element concentrations and also of U-Th-Ra disequilibria in the upper part of the regolith (0-80 cm) and the deeper part of the fractured saprolith and/or bedrock (100cm-200cm). Modeling of the U-Th-Ra data in this deeper part of the profile, using a particle swarm optimization model dedicated to isotopic ratios leads to a regolith production rate at the summit of the watershed of 35 ± 9 T/km²/year. In addition, a numerical optimization for nonlinear inverse problem has been performed to estimate the regolith residence time and the mean denudation rate at the summit from the Beryllium data. The results show that the regolith residence time is about 14 000 years and the mean denudation rate is 32 ± 8 T/km²/year. The consistency between the regolith production rate and the soil denudation rate suggests therefore that in such a temperate context, the long-term mass balance of soil developed on granitic bedrock would be close to a steady state. The data also highlights that the determination of a weathering production rate from analysis of Uranium series nuclides in whole rock samples cannot be easily obtained by analyzing only surficial soil samples, and requires the analysis of the deeper fractured saprolith

  6. Authigenic 10Be/9Be Ratio Signatures of the Cosmogenic Nuclide Production Linked to Geomagnetic Dipole Moment Variation During and Since the Brunhes/Matuyama Boundary

    NASA Astrophysics Data System (ADS)

    Simon, Q.; Thouveny, N.; Bourles, D. L.; Ménabréaz, L.; Valet, J. P.; Valery, G.; Choy, S.

    2015-12-01

    The atmospheric production rate of cosmogenic nuclides is linked to the geomagnetic dipole moment (GDM) by a non-linear inverse relationship. Large amplitude GDM variations associated with reversals and excursions can potentially be reconstructed using time variation of the cosmogenic beryllium-10 (10Be) production recorded in ocean sediments. Downcore profiles of authigenic 10Be/9Be ratios (proxy of atmospheric 10Be production) in oceanic cores provide independent and additional records of the evolution of the geomagnetic intensity and complete previous information derived from relative paleointensity (RPI). Here are presented new authigenic 10Be/9Be results obtained from cores MD05-2920 and from the top of core MD05-2930 collected in the West Equatorial Pacific Ocean. Completing data of Ménabréaz et al. (2012, 2014), these results provide the first continuous 10Be production rate sedimentary record covering the last 800 ka. Along these cores, authigenic 10Be/9Be ratio peaks are recorded - within methodological errors - at the stratigraphic level of RPI lows. High-resolution chronologies (δ18O-derived) lead to interpret these peaks as successive global 10Be overproduction events triggered by geomagnetic dipole lows present in the PISO-1500 and Sint-2000 stacks. The largest amplitude 10Be production enhancement is synchronous to the very large decrease of the dipole field associated with the last polarity reversal (772 ka). It is consistent in shape and duration with the peak recorded in core MD90-0961 from the Maldive area (Indian Ocean) (Valet et al. 2014). Two significant 10Be production enhancements are coeval with the Laschamp (41 ka) and Icelandic basin (190 ka) excursions, while 10Be production peaks of lower amplitude correlate to other recognized excursions such as the Blake (120 ka), Pringle-Falls (215 ka), Portuguese Margin (290 ka), Big Lost (540 ka) among others. This study provides new data on the amplitude and timing of dipole field variations

  7. Cosmogenic Nuclide Dating of Glacial Advances in the Himalaya of Western Garhwal and Southern Himachal Pradesh, India (78°E, 31°N)

    NASA Astrophysics Data System (ADS)

    Scherler, D.; Bodo, B.; Strecker, M. R.; von Blanckenburg, F.; Rood, D.

    2008-12-01

    Recent glacial chronologies from the Himalaya suggest that glaciers are sensitive to changes in the strength of the Indian Summer Monsoon, which is sourced by moisture from the Bay of Bengal. However, a large fraction of the annual snowfall in the orogen may be supplied by the northern hemisphere westerlies (Western Disturbances) during winter. In particular, areas in northern India west of 78° longitude receive less than 60% of their annual precipitation during summer. Our study area lies within the transition zone from a summer to a winter precipitation maximum in northern India in the greater Sutlej River area. The sampling sites for cosmogenic nuclide dating of terminal moraine systems span the northwest-southeast oriented orographic rainfall barrier and exhibit a strong gradient in summer monsoon rainfall. We have collected samples for surface exposure dating of large erratic boulders from well-preserved moraines in three different valleys that are located within a distance of 100-150 km to each other. The main focus of our study lies on a detailed glacial chronology for the strongly monsoon-influenced upper Tons valley in western Garhwal, where at least three glacial stages can be distinguished. Preliminary results indicate that all three moraine systems are of Holocene age. The lowermost moraines occur at an elevation of approx. 2.5 km and at a distance of 18-20 km from the present-day glacier terminus. Holocene moraines at such low elevations have rarely been reported from the Himalaya and we suspect this to be a result of the high proportion of winter snowfall in this part of the mountain range. The much drier Pin and Thangi valleys are located in southern Himachal Pradesh, about 150 km to the north and 100km to the northwest, respectively. The oldest identifiable moraines in the Thangi valley occur at a shorter distance from the present-day glacier terminus, as compared to the Tons and Pin valley. Nevertheless, preliminary early Holocene ages for these

  8. Late Quaternary alluvial fans of Emli Valley in the Ecemiş Fault Zone, south central Turkey: Insights from cosmogenic nuclides

    NASA Astrophysics Data System (ADS)

    Akif Sarıkaya, M.; Yıldırım, Cengiz; Çiner, Attila

    2015-01-01

    Alluvial fans within the paraglacial Ecemiş River drainages on the Aladağlar Mountains in south central Turkey were studied using geomorphological, sedimentological, and chlorine-36 terrestrial cosmogenic nuclide (TCN) surface exposure dating methods to examine the timing of alluvial fan abandonment/incision, and to understand the role of climatic and tectonic processes in the region. These alluvial fan complexes are among the best-preserved succession of alluvial fans in Turkey and they were offset by the major strike-slip Ecemiş Fault of the Central Anatolian Fault Zone. The alluvial fans are mostly composed of well-lithified limestone cobbles (5 to 25 cm in size), and comprise crudely stratified thick beds with a total thickness reaching up to about 80 m. TCN surface exposure dating indicates that the oldest alluvial fan surface (Yalak Fan) was likely formed and subsequently abandoned latest by 136.0 ± 23.4 ka ago, largely on the transition of the Penultimate Glaciation (Marine Isotope Stage 6, MIS 6) to the Last Interglacial (MIS 5) (i.e. Termination II). The second set of alluvial fan (Emli Fan) was possibly developed during the Last Interglacial (MIS 5), and incised twice by between roughly 97.0 ± 13.8 and 81.2 ± 13.2 ka ago. A younger alluvial fan deposit placed on relatively older erosional terraces of the Emli Fan suggests that it may have been produced during the Last Glacial Cycle (MIS 2). These events are similar to findings from other fluvial and lacustrine deposits throughout central Anatolia. The incision times of the Ecemiş alluvial fan surfaces largely coincide with major climatic shifts from the cooler glacial periods to warmer interglacial/interstadial conditions. This indicates that alluvial fans were produced by outwash sediments of paleoglaciers during cooler conditions, and, later, when glaciers started to retreat due to a major warming event, the excess water released from the glaciers incised the pre-existing fan surfaces. An

  9. Heavy metals and coal combustion

    SciTech Connect

    Danihelka, P.; Ochodek, T.; Noskievic, P.; Seidlerova, J.

    1998-04-01

    Combustion of coal may be an important source of heavy metals pollution. The distribution of heavy metals during combustion process has been studied in six power plants, where fuel, bottom ash, fly ash and emissions have been analysed and the relative concentrations of heavy metals have been estimated. For the most volatile metals (arsenic, antimony, lead, and zinc), the redistribution process involving condensation on surface is probable. Some metals like manganese or chromium are concentrated rather in coarse particles. In such cases, no clear conclusion can be made and probably several mechanisms are involved, including mineral form of metal. Typical results of low chlorine coal (0.01-0.03% Cl) exhibit increasing concentration of volatile metals in the magnitude of around one order when going from bottom ash to emissions. Different results have been found in similar operation conditions in the case of high content of chlorine in coal (0.3 % of Cl in coal). In this case, the concentration of metals in emissions is significantly higher and also nickel, copper and manganese concentrations increase. It seems to be probable that chlorine in the coal increases the redistribution of metals by volatile chlorides formation.

  10. Heavy metals in plants and phytoremediation.

    PubMed

    Cheng, Shuiping

    2003-01-01

    In some cases, soil, water and food are heavily polluted by heavy metals in China. To use plants to remediate heavy metal pollution would be an effective technique in pollution control. The accumulation of heavy metals in plants and the role of plants in removing pollutants should be understood in order to implement phytoremediation, which makes use of plants to extract, transfer and stabilize heavy metals from soil and water. The information has been compiled from Chinese publications stemming mostly from the last decade, to show the research results on heavy metals in plants and the role of plants in controlling heavy metal pollution, and to provide a general outlook of phytoremediation in China. Related references from scientific journals and university journals are searched and summarized in sections concerning the accumulation of heavy metals in plants, plants for heavy metal purification and phytoremediation techniques. Plants can take up heavy metals by their roots, or even via their stems and leaves, and accumulate them in their organs. Plants take up elements selectively. Accumulation and distribution of heavy metals in the plant depends on the plant species, element species, chemical and bioavailiability, redox, pH, cation exchange capacity, dissolved oxygen, temperature and secretion of roots. Plants are employed in the decontamination of heavy metals from polluted water and have demonstrated high performances in treating mineral tailing water and industrial effluents. The purification capacity of heavy metals by plants are affected by several factors, such as the concentration of the heavy metals, species of elements, plant species, exposure duration, temperature and pH. Phytoremediation, which makes use of vegetation to remove, detoxify, or stabilize persistent pollutants, is a green and environmentally-friendly tool for cleaning polluted soil and water. The advantage of high biomass productive and easy disposal makes plants most useful to remediate

  11. Heavy Hadron Spectroscopy at CDF

    SciTech Connect

    Fernandez Ramos, Juan Pablo

    2010-12-22

    We present recent CDF results on the properties of hadrons containing heavy quarks. These include measurements of charm and {Sigma}{sub b}{sup -{Sigma}}{sub b}*{sup -} baryon's masses, lifetimes and masses of {Omega}{sub b}{sup -,} {Xi}{sub b}{sup -} and B{sub c}{sup -} and a measurement of exclusive B{sup +}, B{sup 0} and {Lambda}{sub b} lifetimes as well as lifetime ratios (charge conjugate modes are implied throughout the text). We also summarize new measurements of exotic particles X(3872) and Y(4140).

  12. Heavy hadron spectroscopy at CDF

    SciTech Connect

    Fernandez Ramos, Juan Pablo; /Madrid, CIEMAT

    2011-01-01

    We present recent CDF results on the properties of hadrons containing heavy quarks. These include measurements of charm and {Sigma}{sub b}{sup -}{Sigma}*{sub b}{sup -} baryon's masses, lifetimes and masses of {Omega}{sub b}{sup -}, {Xi}{sub b}{sup -} and B{sub c}{sup -} and a measurement of exclusive B{sup +}, B{sup 0} and {Lambda}{sub b} lifetimes as well as lifetime ratios (charge conjugate modes are implied throughout the text). We also summarize new measurements of exotic particles X(3872) and Y(4140).

  13. Catalytic cracking of heavy oils

    SciTech Connect

    Otterstedt, J.E.; Gevert, B.; Sterte, J. )

    1987-08-01

    Of the many factors which influence product yields in a fluid catalytic cracker, the feed stock quality and the catalyst composition are of particular interest as they can be controlled only to a limited extent by the refiner. In the past decade there has been a trend towards using heavier feedstocks in the FCC-unit, which is expected to continue in the foreseeable future. It is therefore important to study how molecular types, characteristic not only of heavy petroleum oil but also of e.g. coal liquid, shale oil and biomass oil, respond to cracking over catalysts of different compositions.

  14. Selective reduction of heavy metals

    SciTech Connect

    Bjorling, G.

    1984-12-11

    The present invention relates to selective reduction of heavy metals out of finey grained, substantially oxidic material by blowing the oxidic material into a furnace together with an amount of reducing agent required for obtaining desired selectivity while simultaneously heat energy is supplied by a gas heated in a plasma generator, the temperature being adjusted to such a level as to correspond to the oxygen potential at which the desired metals are transformed into a particular, isolatable phase as metal melt, metal vapor, speiss or matte and at which the remaining metals enter into a slag phase and can be isolated as slag melt.

  15. Biomolecules for removal of heavy metal.

    PubMed

    Singh, Namita Ashish

    2017-02-23

    Heavy metals are natural constituents of the earth's crust, but some heavy metals like cadmium, lead, mercury, arsenic etc. are injurious to living organisms at higher concentration. Nowadays, anthropogenic activities have altered geochemical cycles and biochemical balance of heavy metals. Biomolecules are used nowadays for removal of heavy metals compared to other synthetic biosorbents due to their environmental friendly nature and cost effectiveness. The goal of this work is to review research work and patents related to adsorption through biomolecules like polysaccharides, polypeptides, lignin etc. and bio-sorption by biological material that are used for heavy metal removal. Biomolecules are cost effective and there have been significant progresses in the remediation of heavy metals but, still there are some problems that need to be rectified for its application at industrial processes.

  16. Pentaquarks and doubly heavy exotic mesons

    NASA Astrophysics Data System (ADS)

    Karliner, Marek

    2016-11-01

    I discuss the experimental evidence for and theoretical interpretation of the new mesons and baryons with two heavy quarks. These include doubly-heavy baryons, exotic hadronic quarkonia and most recently a manifestly exotic pentaquark-like doubly heavy baryon with a minimal quark content uudc¯ discovered by LHCb, whose mass, decay mode and width are in agreement with a prediction based on a physical picture of a deuteron-like Σc D¯* "hadronic molecule".

  17. Differences between heavy and light quarks.

    SciTech Connect

    Maris, P.; Roberts, C. D.

    1997-11-10

    The quark Dyson-Schwinger equation shows that there are distinct differences between light and heavy quarks. The dynamical mass function of the light quarks is characterized by a sharp increase below 1 GeV, whereas the mass function of the heavy quarks is approximately constant in this infrared region. As a consequence, the heavy meson masses increase linearly with the current quark masses, whereas the light pseudoscalar meson masses are proportional to the square root of the current quark masses.

  18. The Bucharest heavy ion accelerator facility

    NASA Astrophysics Data System (ADS)

    Ceauşescu, V.; Dobrescu, S.; Duma, M.; Indreas, G.; Ivaşcu, M.; Păpureanu, S.; Pascovici, G.; Semenescu, G.

    1986-02-01

    The heavy ion accelerator facility of the Heavy Ion Physics Department at the Institute of Physics and Nuclear Engineering in Bucharest is described. The Tandem accelerator development and the operation of the first stage of the heavy ion postaccelerating system are discussed. Details are given concerning the resonance cavities, the pulsing system matching the dc beam to the RF cavities and the computer control system.

  19. The ANSTO high energy heavy ion microprobe

    NASA Astrophysics Data System (ADS)

    Siegele, Rainer; Cohen, David D.; Dytlewski, Nick

    1999-10-01

    Recently the construction of the ANSTO High Energy Heavy Ion Microprobe (HIMP) at the 10 MV ANTARES tandem accelerator has been completed. The high energy heavy ion microprobe focuses not only light ions at energies of 2-3 MeV, but is also capable of focusing heavy ions at high energies with ME/ q2 values up to 150 MeV amu and greater. First performance tests and results are reported here.

  20. The Relativistic Heavy Ion Collider, Rhic

    NASA Astrophysics Data System (ADS)

    Foelsche, H.; Hahn, H.; Harrison, M.; Ozaki, S.; Rhoades-Brown, M. J.

    1993-03-01

    The scope of the first relativistic energy heavy ion collider, RHIC, is discussed. Particular attention is paid to those novel features of a heavy ion collider that are distinct from the more usual proton machines. These features are derived from the experimental requirements of operation with a variety of ion species over a wide energy range as well as the increased demands on available ion sources and injector complexes. Storage of heavy ion beams for many hours is severely impacted by intrabeam scattering.