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Sample records for neutron deficient sr

  1. Description of the neutron deficient Sr and Zr isotopes in the interacting boson model

    Energy Technology Data Exchange (ETDEWEB)

    Bucurescu, D.; Cata, G.; Cutoiu, D.; Constantinescu, G.; Ivascu, M.; Zamfir, N.V. (Institutul Central de Fizica, Bucharest (Romania))

    1983-05-30

    The available experimental data for the neutron deficient isotopes of Sr (78 to 86) and Zr (80 to 86) are collected and compared to the predictions of IBA-1 model calculations. The variations of the collectivity along these two isotopic chains is well reproduced with a set of smoothly varying parameters of the model. The description of both the energy levels and the B(E2) transition probabilities improves with decreasing N, the hamiltonian evolving towards an SU(3) dynamical symmetry. Both the large B(E2) value of the 2/sub 1//sup +/->0/sup +/sub(g.s.) transition and the predicted prolate shape for the very light isotopes, agree well with the recent findings of superdeformed nuclei around Z, N proportional 38. Transition strengths for the (p,t) reaction are calculated and compared to experimental observations for 0/sup +/ states, and a discussion is made about the possible intruder character of the O/sub 2//sup +/ state. The interacting boson-fermion approximation (IBFA) model is used to extend the calculations to some odd nuclei. Two shell (1gsub(9/2), 2dsub(5/2)) calculations are performed for the positive-parity states in /sup 83/Sr, /sup 81/Sr and /sup 85/Y and they compare well with the experimental level scheme of these nuclei below 3 MeV excitation.

  2. Mass measurements on neutron-deficient Sr and neutron-rich Sn isotopes with the ISOLTRAP mass spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Sikler, G. [MPI fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany) and TRIUMF, 4004 Wesbrook Mall, Vancouver BC, V6T 2A3 (Canada)]. E-mail: g.sikler@mpi-hd.mpg.de; Audi, G. [CSNSM-IN2P3-CNRS, Batiment 108, 91405 Orsay-Campus (France); Beck, D. [GSI, Planckstr. 1, 64291 Darmstadt (Germany); Blaum, K. [Johannes Gutenberg-Universitaet Mainz, Staudingerweg 7, 55128 Mainz (Germany); Bollen, G. [NSCL, Michigan State University, East Lansing, MI 48824-1321 (United States); Herfurth, F. [GSI, Planckstr. 1, 64291 Darmstadt (Germany); Kellerbauer, A. [CERN, 1211 Geneva 23 (Switzerland); Kluge, H.-J. [GSI, Planckstr. 1, 64291 Darmstadt (Germany); Lunney, D. [CSNSM-IN2P3-CNRS, Batiment 108, 91405 Orsay-Campus (France); Oinonen, M. [Helsinki Institute of Physics, P.O. Box 64, 00014 University of Helsinki (Finland); Scheidenberger, C. [GSI, Planckstr. 1, 64291 Darmstadt (Germany); Schwarz, S. [NSCL, Michigan State University, East Lansing, MI 48824-1321 (United States); Szerypo, J. [LMU Muenchen, Am Coulombwall 1, 85748 Garching (Germany)

    2005-12-26

    The atomic masses of {sup 76,77,80,81,86,88}Sr and {sup 124,129,130,131,132}Sn were measured by means of the Penning trap mass spectrometer ISOLTRAP at ISOLDE/CERN. {sup 76}Sr is now the heaviest N=Z nucleus for which the mass is measured to a precision better than 35 keV. For the tin isotopes in the close vicinity of the doubly magic nucleus {sup 132}Sn, mass uncertainties below 20 keV were achieved. An atomic mass evaluation was carried out taking other experimental mass values into account by performing a least-squares adjustment. Some discrepancies between older experimental values and the ones reported here emerged and were resolved. The results of the new adjustment and their impact will be presented.

  3. Mass measurements on neutron-deficient Sr and neutron-rich Sn isotopes with the ISOLTRAP mass spectrometer

    CERN Document Server

    Sikler, G; Beck, D; Blaum, K; Bollen, G; Herfurth, F; Kellerbauer, A G; Kluge, H J; Lunney, M D; Oinonen, M; Scheidenberger, C; Schwarz, S; Szerypo, J

    2005-01-01

    The atomic masses of $^{76,77,80,81,86,88}$Sr and $^{124,129,130,131,132}$Sn were measured by means of the Penning trap mass spectrometer ISOLTRAP at ISOLDE/CERN. $^{76}$Sr is now the heaviest N=Z nucleus for which the mass is measured to a precision better than 35 keV. For the tin isotopes in the close vicinity of the doubly magic nucleus $^{132}$Sn, mass uncertainties below 20 keV were achieved. An atomic mass evaluation was carried out taking other experimental mass values into account by performing a least-squares adjustment. Some discrepancies between older experimental values and the ones reported here emerged and were resolved. The results of the new adjustment and their impact will be presented.

  4. Photodissociation of neutron deficient nuclei

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-03-15

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

  5. Shape coexistence in neutron-rich Sr isotopes : Coulomb excitation of 98Sr

    NARCIS (Netherlands)

    Clément, E; Görgen, A.; Korten, W.; Walle J. van de, [No Value

    2010-01-01

    In this addendum we ask for beam time to perform Coulomb excitation of 98Sr in order to complete our program on the study of shape coexistence and evolution of collectivity in neutron rich strontium isotopes at N=60.

  6. Laser spectroscopy of neutron deficient Sn isotopes

    CERN Multimedia

    We propose to study the ground state properties of neutron-deficient Sn isotopes towards the doubly-magic nucleus $^{100}$Sn. Nuclear spins, changes in the rms charge radii and electromagnetic moments of $^{101-121}$Sn will be measured by laser spectroscopy using the CRIS experimental beam line. These ground-state properties will help to clarify the evolution of nuclear structure properties approaching the $\\textit{N = Z =}$ 50 shell closures. The Sn isotopic chain is currently the frontier for the application of state-of-the-art ab-initio calculations. Our knowledge of the nuclear structure of the Sn isotopes will set a benchmark for the advances of many-body methods, and will provide an important test for modern descriptions of the nuclear force.

  7. Radiochemical studies of neutron deficient actinide isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Williams, K.E.

    1978-04-01

    The production of neutron deficient actinide isotopes in heavy ion reactions was studied using alpha, gamma, x-ray, and spontaneous fission detection systems. A new isotope of berkelium, /sup 242/Bk, was produced with a cross-section of approximately 10 ..mu..b in reactions of boron on uranium and nitrogen on thorium. It decays by electron capture with a half-life of 7.0 +- 1.3 minutes. The alpha-branching ratio for this isotope is less than 1% and the spontaneous fission ratio is less than 0.03%. Studies of (Heavy Ion, pxn) and (Heavy Ion, ..cap alpha..xn) transfer reactions in comparison with (Heavy ion, xn) compound nucleus reactions revealed transfer reaction cross-sections equal to or greater than the compound nucleus yields. The data show that in some cases the yield of an isotope produced via a (H.I.,pxn) or (H.I.,..cap alpha..xn) reaction may be higher than its production via an xn compound nucleus reaction. These results have dire consequences for proponents of the ''Z/sub 1/ + Z/sub 2/ = Z/sub 1+2/'' philosophy. It is no longer acceptable to assume that (H.I.,pxn) and (H.I.,..cap alpha..xn) product yields are of no consequence when studying compound nucleus reactions. No evidence for spontaneous fission decay of /sup 228/Pu, /sup 230/Pu, /sup 232/Cm, or /sup 238/Cf was observed indicating that strictly empirical extrapolations of spontaneous fission half-life data is inadequate for predictions of half-lives for unknown neutron deficient actinide isotopes.

  8. Mass measurements of neutron-rich Rb and Sr isotopes

    CERN Document Server

    Klawitter, R; Brodeur, M; Chowdhury, U; Chausdhuri, A; Fallis, J; Gallant, A T; Grossheim, A; Kwiatkowski, A A; Lascar, D; Leach, K G; Lennarz, A; Macdonald, T D; Pearkes, J; Seeraji, S; Simon, M C; Simon, V V; Schultz, B E; Dilling, J

    2015-01-01

    We report on the mass measurements of several neutron-rich $\\mathrm{Rb}$ and $\\mathrm{Sr}$ isotopes in the $A \\approx 100$ region with the TITAN Penning-trap mass spectrometer. Using highly charged ions in the charge state $q=10+$, the masses of $^{98,99}\\mathrm{Rb}$ and $^{98-100}\\mathrm{Sr}$ have been determined with a precision of $6 - 12\\ \\mathrm{keV}$, making their uncertainty negligible for r-process nucleosynthesis network calculations. The mass of $^{101}\\mathrm{Sr}$ has been determined directly for the first time with a precision eight times higher than the previous indirect measurement and a deviation of $3\\sigma$ when compared to the Atomic Mass Evaluation. We also confirm the mass of $^{100}\\mathrm{Rb}$ from a previous measurement. Furthermore, our data indicates the existance of a low-lying isomer with $80\\ \\mathrm{keV}$ excitation energy in $^{98}\\mathrm{Rb}$. We show that our updated mass values lead to minor changes in the r-process by calculating fractional abundances in the $A\\approx 100$ re...

  9. Shell Model Description of Neutron-Deficient Sn Isotopes

    Institute of Scientific and Technical Information of China (English)

    Erdal Dikmen

    2009-01-01

    The shell model calculations in the sdgh major shell for the neutron-deficient 106,107,108,109Sn isotopes have been carried out by using CD-Bonn and Nijmegenl two-body effective nucleon-nucleon interactions. The single-shell states and the corresponding matrix elements needed for describing Sn isotopes are reconstructed to calculate the coefficient of fractional parantage by reducing the calculation requirements. This reconstruction allows us to do the shell model calculations of the neutron deficient Sn isotopes in very reasonable time. The results are compared to the recent high-resolution experimental data and found to be in good agreement with experiments.

  10. Two-neutron knockout from neutron-deficient $^{34}$Ar, $^{30}$S, and $^{26}$Si

    CERN Document Server

    Yoneda, K; Brown, B A; Campbell, C M; Cook, J M; Cottle, P D; Davies, A D; Dinca, D C; Gade, A; Glasmacher, T; Hansen, P G; Hoagland, T; Kemper, K W; Lecouey, J L; Müller, W F; Obertelli, A; Reynolds, R R; Terry, J R; Tostevin, J A; Zwahlen, H

    2006-01-01

    Two-neutron knockout reactions from nuclei in the proximity of the proton dripline have been studied using intermediate-energy beams of neutron-deficient $^{34}$Ar, $^{30}$S, and $^{26}$Si. The inclusive cross sections, and also the partial cross sections for the population of individual bound final states of the $^{32}$Ar, $^{28}$S and $^{24}$Si knockout residues, have been determined using the combination of particle and $\\gamma$-ray spectroscopy. Similar to the two-proton knockout mechanism on the neutron-rich side of the nuclear chart, these two-neutron removal reactions from already neutron-deficient nuclei are also shown to be consistent with a direct reaction mechanism.

  11. Neutron and Alpha Structure in Neutron Deficient Nuclei in Astrophysics

    Institute of Scientific and Technical Information of China (English)

    S. Kubono; T. Hashimoto; Y. Wakabayashi; N. Iwasa; S. Kato; T. Komatsubara; D. N. Binh; L. H. Khiem; N. N. Duy; T. Kawabata; C. Spitaleri; 何建军; G. G. Rapisarda; M. La Cognata; L. Lamia; R. G. Pizzone; S. Romano; A. Coc; N. de Sereville; F. Hammache; G. Kiss; S. Bishop; H. Yamaguchi; D. M. Kahl; S. Hayakawa; T. Teranishi; S. Cheribini; M. Gulino; Y. K. Kwon

    2016-01-01

    The paper includes discussions on the important role of neutron and alpha configurations in proton-rich nuclei in nuclear astrophysics in terms of nucleosynthesis under extremely high-temperature hydrogenburning conditions. The νp-process, which is supposed to take place at the very early epoch of type II supernovae, has considerable neutrons and alphas together with protons. The alpha-induced reactions on proton-rich unstable nuclei in the light mass regions is expected to play a crucial role, but very few of them were investigated well yet because of the experimental difficulties. Specifically, I report our recent experimental effort for the breakout process from the pp-chain region, 7Be(α,γ)11C(α,p)14N under the νp-process. The neutron-induced reactions on proton-rich nuclei, which is even more a challenging subject, were investigated previously for very few nuclei. One possible experimental method is the Trojan Horse Method (THM). We successfully have applied THM to the 18F(n,α)14N reaction study with an unstable beam of 18F.

  12. Shape coexistence in neutron-rich Sr isotopes : Coulomb excitation of $^{96}$Sr

    CERN Multimedia

    Clement, E; Siem, S; Czosnyka, T

    2007-01-01

    The nuclei in the mass region A $\\cong$ 100 around Sr and Zr show a dramatic change of the nuclear ground-state shape from near spherical for N $\\leq$ 58 to strongly deformed for N $\\geq$ 60. Theoretical calculations predict the coexistence of slightly oblate and strongly prolate deformed configurations in the transitional region. However, excited rotational structures based on the highly deformed configuration, which becomes the ground state at N = 60, are not firmly established in the lighter isotopes, and the earlier interpretation of a very abrupt change of shape has been challenged by recent experimental results in favor of a rather gradual change. We propose to study the electromagnetic properties of the neutron-rich nucleus $_{38}^{96}$Sr$_{58}$ by low-energy Coulomb excitation using the REX-ISOLDE facility and the MINIBALL detector array. Both transitional and diagonal matrix elements will be extracted, resulting in a complete description of the transition strengths and quadrupole moments of the low-l...

  13. Decay-Assisted Laser Spectroscopy of Neutron-Deficient Francium

    CERN Document Server

    Lynch, K M; Bissell, M L; Budincevic, I; Cocolios, T E; De Groote, R P; De Schepper, S; Fedosseev, V N; Flanagan, K T; Franchoo, S; Garcia Ruiz, R F; Heylen, H; Marsh, B A; Neyens, G; Procter, T J; Rossel, R E; Rothe, S; Strashnov, I; Stroke, H H; Wendt, K D A

    2014-01-01

    This paper reports on the hyperfine-structure and radioactive-decay studies of the neutron-deficient francium isotopes $^{202-206}$Fr performed with the Collinear Resonance Ionization Spectroscopy (CRIS) experiment at the ISOLDE facility, CERN. The high resolution innate to collinear laser spectroscopy is combined with the high efficiency of ion detection to provide a highly-sensitive technique to probe the hyperfine structure of exotic isotopes. The technique of decay-assisted laser spectroscopy is presented, whereby the isomeric ion beam is deflected to a decay spectroscopy station for alpha-decay tagging of the hyperfine components. Here, we present the first hyperfine-structure measurements of the neutron-deficient francium isotopes $^{202-206}$Fr, in addition to the identification of the low-lying states of $^{202,204}$Fr performed at the CRIS experiment.

  14. Collectivity of the neutron-deficient odd yttrium isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Bucurescu, D.; Cata, G.; Ivascu, M.; Zamfir, N.V.; Liang, C.F.; Paris, P.

    1988-08-01

    Multishell IBFM-1 calculations are reported for the neutron-deficient odd yttrium isotopes (79-85), which give a good description of both the positive and negative parity levels known experimentally. An exchange force whose intensity varies with the mass number is required. This phenomenological variation reflects qualitatively the microscopic origin of the exchange term, and also points to possible systematics of the model parameters in the ALPHA approx. = 80 region of the Nsub(p)Nsub(n) type.

  15. Morphological and behavioral characterization of adult mice deficient for SrGAP3.

    Science.gov (United States)

    Bertram, Jonathan; Koschützke, Leif; Pfannmöller, Jörg P; Esche, Jennifer; van Diepen, Laura; Kuss, Andreas W; Hartmann, Bianca; Bartsch, Dusan; Lotze, Martin; von Bohlen Und Halbach, Oliver

    2016-10-01

    SrGAP3 belongs to the family of Rho GTPase proteins. These proteins are thought to play essential roles in development and in the plasticity of the nervous system. SrGAP3-deficient mice have recently been created and approximately 10 % of these mice developed a hydrocephalus and died shortly after birth. The others survived into adulthood, but displayed neuroanatomical alteration, including increased ventricular size. We now show that SrGAP3-deficient mice display increased brain weight together with increased hippocampal volume. This increase was accompanied by an increase of the thickness of the stratum oriens of area CA1 as well as of the thickness of the molecular layer of the dentate gyrus (DG). Concerning hippocampal adult neurogenesis, we observed no significant change in the number of proliferating cells. The density of doublecortin-positive cells also did not vary between SrGAP3-deficient mice and controls. By analyzing Golgi-impregnated material, we found that, in SrGAP3-deficient mice, the morphology and number of dendritic spines was not altered in the DG. Likewise, a Sholl-analysis revealed no significant changes concerning dendritic complexity as compared to controls. Despite the distinct morphological alterations in the hippocampus, SrGAP3-deficient mice were relatively inconspicuous in their behavior, not only in the open-field, nest building but also in the Morris water-maze. However, the SrGAP3-deficient mice showed little to no interest in burying marbles; a behavior that is seen in some animal models related to autism, supporting the view that SrGAP3 plays a role in neurodevelopmental disorders.

  16. Spin assignments of nuclear levels above the neutron binding energy in $^{88}$Sr

    CERN Multimedia

    Neutron resonances reveal nuclear levels in the highly excited region of the nucleus around the neutron binding energy. Nuclear level density models are therefore usually calibrated to the number of observed levels in neutron-induced reactions. The gamma-ray cascade from the decay of the highly excited compound nucleus state to the ground state show dierences dependent on the initial spin. This results in a dierence in the multiplicity distribution which can be exploited. We propose to use the 4${\\pi}$ total absorption calorimeter (TAC) at the n TOF facility to determine the spins of resonances formed by neutrons incident on a metallic $^{87}$Sr sample by measuring the gamma multiplicity distributions for the resolved resonances. In addition we would like to use the available enriched $^{87}$Sr target for cross section measurements with the C$\\scriptscriptstyle{6}$D$\\scriptscriptstyle{6}$ detector setup.

  17. Collinear Resonance Ionization Spectroscopy of Neutron-Deficient Francium Isotopes

    CERN Document Server

    Flanagan, K T; Ruiz, R F Garcia; Budincevic, I; Procter, T J; Fedosseev, V N; Lynch, K M; Cocolios, T E; Marsh, B A; Neyens, G; Strashnov, I; Stroke, H H; Rossel, R E; Heylen, H; Billowes, J; Rothe, S; Bissell, M L; Wendt, K D A; de Groote, R P; De Schepper, S

    2013-01-01

    The magnetic moments and isotope shifts of the neutron-deficient francium isotopes Fr202-205 were measured at ISOLDE-CERN with use of collinear resonance ionization spectroscopy. A production-to-detection efficiency of 1\\% was measured for Fr-202. The background from nonresonant and collisional ionization was maintained below one ion in 10(5) beam particles. Through a comparison of the measured charge radii with predictions from the spherical droplet model, it is concluded that the ground-state wave function remains spherical down to Fr-205, with a departure observed in Fr-203 (N = 116).

  18. Mechanism of fission of neutron-deficient actinoids nuclides

    Energy Technology Data Exchange (ETDEWEB)

    Sueki, Keisuke; Nakahara, Hiromichi [Tokyo Metropolitan Univ., Hachioji (Japan). Faculty of Science; Tanase, Masakazu; Nagame, Yuichiro; Shinohara, Nobuo; Tsukada, Kazuaki

    1996-01-01

    A heavy ion reaction ({sup 19}F+{sup 209}Bi) is selected. The reaction produces neutron-deficient {sup 228}U which is compound nucleus with a pair of Rb(z=37) and Cs(Z=55). Energy dissipation problem of nucleus was studied by measuring the isotope distribution of two fissile nuclides. Bismuth metal evaporated on aluminium foil was irradiated by {sup 19}F with the incident energy of 105-128 MeV. We concluded from the results that the excess energy of reaction system obtained with increasing the incident energy is consumed by (1) light Rb much more than Cs and (2) about 60% of energy is given to two fission fragments and the rest 40% to the translational kinetic energy or unknown anomalous {gamma}-ray irradiation. (S.Y.)

  19. New neutron-deficient isotopes from $^{78}$Kr fragmentation

    CERN Document Server

    Blank, B; Ascher, P; Gerbaux, M; Giovinazzo, J; Grevy, S; Nieto, T Kurtukian; Magron, C; Agramunt, J; Algora, A; Guadilla, V; Montaner-Piza, A; Morales, A I; Orrigo, S E A; Rubio, B; Ahn, D S; Doornenbal, P; Fukuda, N; Inabe, N; Kiss, G; Kubo, T; Kubono, S; Nishimura, S; Phong, V H; Sakurai, H; Shimizu, Y; Soderstrom, P -A; Sumikama, T; Suzuki, H; Takeda, H; Wu, J; Fujita, Y; Tanaka, M; Gelletly, W; Aguilera, P; Molina, F; Diel, F; Lubos, D; de Angelis, G; Napoli, D; Borcea, C; Boso, A; Cakirli, R B; Ganioglu, E; Chiba, J; Nishimura, D; Oikawa, H; Takei, Y; Yagi, S; Wimmer, K; de France, G; Go, S

    2016-01-01

    In an experiment with the BigRIPS separator at the RIKEN Nishina Center, the fragmentation of a $^{78}$Kr beam allowed the observation of new neutron-deficient isotopes at the proton drip-line. Clean identification spectra could be produced and $^{63}$Se, $^{67}$Kr, and $^{68}$Kr were identified for the first time. In addition, $^{59}$Ge was also observed. Three of these isotopes, $^{59}$Ge, $^{63}$Se, and $^{67}$Kr, are potential candidates for ground-state two-proton radioactivity. In addition, the isotopes $^{58}$Ge, $^{62}$Se, and $^{66}$Kr were also sought but without success. The present experiment also allowed the determination of production cross sections for some of the most exotic isotopes. These measurements confirm the trend already observed that the empirical parameterization of fragmentation cross sections, EPAX, significantly overestimates experimental cross sections in this mass region.

  20. New neutron-deficient isotopes from 78Kr fragmentation

    Science.gov (United States)

    Blank, B.; Goigoux, T.; Ascher, P.; Gerbaux, M.; Giovinazzo, J.; Grévy, S.; Kurtukian Nieto, T.; Magron, C.; Agramunt, J.; Algora, A.; Guadilla, V.; Montaner-Piza, A.; Morales, A. I.; Orrigo, S. E. A.; Rubio, B.; Ahn, D. S.; Doornenbal, P.; Fukuda, N.; Inabe, N.; Kiss, G.; Kubo, T.; Kubono, S.; Nishimura, S.; Phong, V. H.; Sakurai, H.; Shimizu, Y.; Söderström, P.-A.; Sumikama, T.; Suzuki, H.; Takeda, H.; Wu, J.; Fujita, Y.; Tanaka, M.; Gelletly, W.; Aguilera, P.; Molina, F.; Diel, F.; Lubos, D.; de Angelis, G.; Napoli, D.; Borcea, C.; Boso, A.; Cakirli, R. B.; Ganioglu, E.; Chiba, J.; Nishimura, D.; Oikawa, H.; Takei, Y.; Yagi, S.; Wimmer, K.; de France, G.; Go, S.

    2016-06-01

    In an experiment with the RIKEN projectile fragment separator called BigRIPS at the RIKEN Nishina Center, the fragmentation of a 78Kr beam allowed the observation of new neutron-deficient isotopes at the proton drip line. Clean identification spectra could be produced and 63Se,67Kr, and 68Kr were identified for the first time. In addition, 59Ge was also observed. Three of these isotopes, 59Ge,63Se, and 67Kr, are potential candidates for ground-state two-proton radioactivity. In addition, the isotopes 58Ge,62Se, and 66Kr were also sought but without success. The present experiment also allowed the determination of production cross sections for some of the most exotic isotopes. These measurements confirm the trend already observed that the empirical parametrization of fragmentation cross sections, EPAX, significantly overestimates experimental cross sections in this mass region.

  1. Neutron scattering and μSR investigations of quasi-one-dimensional magnetism in the spin =3/2 compound Li3RuO4

    DEFF Research Database (Denmark)

    Manuel, P.; Adroja, D. T.; Lindgård, Per-Anker

    2011-01-01

    The S = 3/2, quasi-one-dimensional (1D) zig-zag chain Heisenberg antiferromagnet Li3RuO4 has been investigated using heat capacity, inelastic neutron scattering, neutron diffraction, and μSR measurements on a powder sample. Our neutron diffraction and μSR studies confirm a long-range ordering of ...

  2. Deficiency in Monte Carlo simulations of coupled neutron-gamma-ray fields

    NARCIS (Netherlands)

    Maleka, Peane P.; Maucec, Marko; de Meijer, Robert J.

    2011-01-01

    The deficiency in Monte Carlo simulations of coupled neutron-gamma-ray field was investigated by benchmarking two simulation codes with experimental data. Simulations showed better correspondence with the experimental data for gamma-ray transport only. In simulations, the neutron interactions with m

  3. β+/EC decay rates of deformed neutron-deficient nuclei in the deformed QRPA with realistic interactions

    Directory of Open Access Journals (Sweden)

    Dongdong Ni

    2015-05-01

    Full Text Available The weak-decay (β+ and EC rates of neutron-deficient Kr, Sr, Zr, and Mo isotopes are investigated within the deformed quasiparticle random-phase approximation with realistic nucleon–nucleon interactions. The particle–particle and particle–hole channels of residual interactions are handled in large single-particle model spaces, based on the Brückner G-matrix with charge-dependent Bonn nucleon–nucleon forces. Contributions from allowed Gamow–Teller and Fermi transitions as well as first-forbidden transitions are calculated. The calculated half-lives show good agreement with the experimental data over a wide range of magnitude, from 10−2 to 107 s. Moreover, predictions of β-decay half-lives are made for some extremely proton-rich isotopes, which could be useful for future experiments.

  4. Study of Neutron-Deficient $^{202-205}$Fr Isotopes with Collinear Resonance Ionization Spectroscopy

    CERN Document Server

    De Schepper, Stijn; Cocolios, Thomas; Budincevic, Ivan

    The scope of this master’s thesis is the study of neutron-deficient $^{202−205}$Fr isotopes. These isotopes are inside the neutron-deficient lead region, a region that has shown evidence of shape coexistence. For this thesis, this discussion is limited to the phenomenon where a low lying excited state has a different shape than the ground state. Shape coexistence is caused by intruder states. These are single-particle Shell Model states that are perturbed in energy due to the interaction with a deformed core. In the neutron-deficient lead region the main proton intruder orbit is the 3s$_{1/2}$orbit. When going towards more neutron-deficient isotopes, deformation increases. The $\\pi3s_{1/2}$orbit will rise in energy and will eventually become the ground state in odd- A bismuth (Z=83) isotopes. It is also observed in odd-A astatine (Z=85) isotopes, already in less neutron-deficient nuclei. The same phenomenon is expected to be present francium (Z=87) isotopes already at $^{199}$Fr. Although it is currently ...

  5. A neutron scattering study of the crystal and magnetic structure of Sr2CrOsO6

    Science.gov (United States)

    Krockenberger, Y.; Reehuis, M.; Tovar, M.; Mogare, K.; Jansen, M.; Alff, L.

    2007-03-01

    Recently, the new osmium-based ferrimagnetic double perovskite Sr2CrOsO6 has been reported to have the highest Curie temperature (˜725 K) within this material class [Y. Krockenberger, K. Mogare, M. Reehuis, M. Tovar, M. Jansen, G. Vaitheeswaran, V. Kanchana, A. Delin, F. Wilhelm, A. Rogalev, A. Winkler, L. Alff, preprint, 2006]. Here, we report details about the crystal and magnetic structure of Sr2CrOsO6 as obtained by neutron powder diffraction.

  6. Collinear antiferromagnetism in trigonal SrMn2As2 revealed by single crystal neutron diffraction

    Science.gov (United States)

    Kreyssig, A.; Das, P.; Sangeetha, N. S.; Benson, Z. A.; Heitman, T.; Johnston, D. C.; Goldman, A. I.

    FeAs-based compounds and related materials have been an area of intense research in understanding the complex interplay between magnetism and superconductivity. Here we report on the magnetic structure of SrMn2As2 that crystallizes in a trigonal structure (P 3 m1) and undergoes an antiferromagnetic (AFM) transition at TN ~ 120 K. The temperature dependence of the magnetic susceptibility remains nearly constant below TN with H ∥ c while it decreases significantly with H ∥ ab . This shows that the local Mn moments order and lie in the ab plane instead of aligning along the c axis as in BaMn2As2. Single crystal neutron diffraction measurements on SrMn2As2 determined that the Mn moments are collinearly aligned in a G-type AFM order with AFM alignments between a moment and all nearest neighbors in the basal plane and also perpendicular to it. This manifests that G-type AFM order is robust for Mn122 systems despite different symmetries, i.e. tetragonal for BaMn2As2 and trigonal for SrMn2As2.Work at Ames Laboratory was supported by the DOE, BES, Division of Materials Sciences & Engineering, through DE-AC02-07CH11358. This research used resources at University of Missouri Research Reactor.

  7. Search for long-lived isomeric states in neutron-deficient thorium isotopes

    CERN Document Server

    Lachner, J; Fästermann, T; Korschinek, G; Poutivtsev, M; Rugel, G; 10.1103/PhysRevC.78.064313

    2009-01-01

    The discovery of naturally occurring long-lived isomeric states (t_1/2 > 10^8 yr) in the neutron-deficient isotopes 211,213,217,218Th [A. Marinov et al., Phys. Rev. C 76, 021303(R) (2007)] was reexamined using accelerator mass spectrometry (AMS). Because AMS does not suffer from molecular isobaric background in the detection system, it is an extremely sensitive technique. Despite our up to two orders of magnitude higher sensitivity we cannot confirm the discoveries of neutron-deficient thorium isotopes and provide upper limits for their abundances.

  8. Research Update: Plentiful magnetic moments in oxygen deficient SrTiO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Bezanilla, Alejandro, E-mail: alejandrolb@gmail.com [Argonne National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois 60439 (United States); Ganesh, P. [Center for Nanophase Materials Science, Oak Ridge National Laboratory, One Bethel Valley Road, Tennessee 37831 (United States); Littlewood, Peter B. [Argonne National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois 60439 (United States); James Franck Institute, University of Chicago, Chicago, Illinois 60637 (United States)

    2015-10-01

    Correlated band theory is employed to investigate the magnetic and electronic properties of different arrangements of oxygen di- and tri-vacancy clusters in SrTiO{sub 3}. Hole and electron doping of oxygen deficient SrTiO{sub 3} yields various degrees of magnetization as a result of the interaction between localized magnetic moments at the defect sites. Different kinds of Ti atomic orbital hybridization are described as a function of the doping level and defect geometry. We find that magnetism in SrTiO{sub 3−δ} is sensitive to the arrangement of neighbouring vacancy sites, charge carrier density, and vacancy-vacancy interaction. Permanent magnetic moments in the absence of vacancy doping electrons are observed. Our description of the charged clusters of oxygen vacancies widens the previous descriptions of mono- and multi-vacancies and points out the importance of the controlled formation at the atomic level of defects for the realization of transition metal oxide based devices with a desirable magnetic performance.

  9. Theoretical predictions on production of neutron-deficient nuclei with Z ≥ 93 in multinucleon transfer reactions

    Science.gov (United States)

    Zhu, Long; Su, Jun; Zhang, Feng-Shou

    2017-08-01

    Within the framework of dinuclear system model, the transfer reactions 58Ni + 233U, 58Ni + 238U, and 64Ni + 238U are investigated. The influences of projectile and target neutron numbers on cross sections of producing neutron-deficient actinide nuclei in transfer reactions are studied. It is found that the system 58Ni + 233U with smaller neutron excess is favorable to produce neutron-deficient nuclei. We predict the production cross sections of neutron-deficient nuclei with Z = 93- 98 in transfer reactions 58Ni + 233U and 40Ca + 245Cm with different incident energies. We find the transfer reactions 58Ni + 233U and 40Ca + 245Cm are feasible for producing neutron-deficient actinide nuclei in future experiments.

  10. Crystal Structure and Magnetic Properties of an oxygen deficient n = 2 Ruddlesden-Popper phase Sr3Co2O5.67

    Science.gov (United States)

    Hill, Julienne M.; Mitchell, John F.; Dabrowski, Bogdan

    2006-03-01

    Interest in charge, orbital, and spin state phenomena in perovskite and related cobalt oxides is a growing area of transition metal oxide physics. Recently, J. Matsuno et al. have found that epitaxial films of the n = 1 Ruddlesden-Popper (R-P) phase Sr2CoO4 are metallic ferromagnets with relatively high TC ˜ 250 K. This is particularly interesting in light of the formal oxidation state of Co, Co^4+, offering no clear source of carriers. To extend the materials chemistry and physics of the R-P series of cobaltites, we have synthesized the n = 2 R-P phase Sr3Co2O7-δ in bulk form. The crystal structure [from neutron powder diffraction (NPD) data] of our most oxygen-deficient sample, Sr3Co2O5.67 is orthorhombic Immm with a = 3.94025(9) å, b = 3.67479(9) å and c = 20.6642(5) å. The magnetization versus temperature data show two antiferromagnetic transitions at approximately 170 K and 220 K. To further elucidate the magnetic properties of this material, we have conducted a temperature-dependent NPD study. The low temperature magnetic structure is surprisingly complex and suggestive of an incommensurate ordering wave vector. Full details and results of the NPD study will be given. J. Matsuno et al., PRL 93, 167202 (2004).

  11. ALPHA-DECAY PROPERTIES OF NEUTRON-DEFICIENT POLONIUM AND RADON NUCLEI

    NARCIS (Netherlands)

    WAUTERS, J; DENDOOVEN, P; HUYSE, M; REUSEN, G; VANDUPPEN, P; LIEVENS, P

    Chemically purified and mass-separated Rn isotopes are used to deduce the a branching ratios of the Po daughter nuclei. The obtained values are systematically lower than the previously known values. Combined with more accurate measurements of the half-lives of the neutron-deficient Po isotopes, a

  12. Fast neutron radiation induced Glu-B1 deficient lines of an elite bread wheat variety

    Science.gov (United States)

    Five isogenic wheat lines deficient in high-molecular weight subunit (HMW-GS) proteins encoded by the B-genome were identified from a fast-neutron radiation-mutagenized population of Summit, an elite variety of bread wheat (Triticum aestivum L.). The mutant lines differ from the wild-type progenit...

  13. Existence of long-lived isomeric states in naturally-occurring neutron-deficient Th isotopes

    CERN Document Server

    Marinov, A; Kashiv, Y; Halicz, L; Segal, I; Pape, A; Gentry, R V; Miller, H W; Kolb, D; Brandt, R

    2006-01-01

    Evidence for the existence of long-lived neutron-deficient isotopes has been found in a study of naturally-occurring Th using iductively coupled plasma-sector field mass spectrometry. They are interpreted as belonging to the recently discovered class of long-lived high spin super- and hyperdeformed isomers.

  14. ALPHA-DECAY PROPERTIES OF NEUTRON-DEFICIENT POLONIUM AND RADON NUCLEI

    NARCIS (Netherlands)

    WAUTERS, J; DENDOOVEN, P; HUYSE, M; REUSEN, G; VANDUPPEN, P; LIEVENS, P

    1993-01-01

    Chemically purified and mass-separated Rn isotopes are used to deduce the a branching ratios of the Po daughter nuclei. The obtained values are systematically lower than the previously known values. Combined with more accurate measurements of the half-lives of the neutron-deficient Po isotopes, a pr

  15. Structural and transport properties of Sr2VO3-δFeAs superconductors with different oxygen deficiencies

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Sr2VO3-δFeAs superconductors with different oxygen deficiencies have been successfully fabricated.It is found that the superconducting transition temperature drops down monotonically with the increase of nominal oxygen deficiency.The diminishing of superconductivity is accompanied by the enhancement of residual resistivity,indicating an anomalous scattering effect induced by the oxygen deficiency.The highest superconducting transition temperature at about 36 K is achieved near the stoichiometrical sample Sr2VO2.9FeAs.The Hall effect measurements reveal that the density of charge carriers(electron-like here) varies qualitatively with the increase of nominal oxygen deficiency.Magnetotransport measurements show that the superconducting transition changes from one-step-like shape at low fields to two-step-like one at high fields,indicating an enhanced vortex motion due to the high anisotropy.

  16. Spectroscopy of low-lying states in neutron-deficient astatine and francium nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Jakobsson, U., E-mail: ulrjak@kth.se; Cederwall, B. [KTH, The Division of Nuclear Physics, AlbaNova University Center, SE-10691 Stockholm (Sweden); Uusitalo, J.; Auranen, K.; Badran, H.; Cox, D. M.; Grahn, T.; Greenlees, P. T.; Julin, R.; Juutinen, S.; Herzáň, A.; Konki, J.; Leino, M.; Mallaburn, M.; Pakarinen, J.; Papadakis, P.; Partanen, J.; Rahkila, P.; Sandzelius, M.; Sarén, J. [University of Jyvaskyla, Department of Physics, P.O. Box 35, FI-40014 University of Jyvaskyla (Finland); and others

    2015-10-15

    Low-lying states in neutron-deficient astatine and francium nuclei have been studied by means of in-beam and delayed spectroscopy. The 13/2{sup +} state has been observed in francium nuclei with a similar down-sloping trend as in neighbouring astatine and bismuth isotopes, as a function of decreasing neutron number. A systematic trend can also now be seen for the 1/2{sup +} state both in astatine and francium nuclei, where the level energy decreases steeply as a function of neutron number when moving further away from the neutron shell closure. This trend is very similar between astatine nuclei and their francium isotones. Moreover, shape coexistence has been observed between the 13/2{sup +} state and the spherical 9/2{sup −} ground state in {sup 203}Fr and {sup 205}Fr.

  17. The physical properties of oxygen-deficient perovskite SrPbO{sub 3-{delta}}

    Energy Technology Data Exchange (ETDEWEB)

    Hadjarab, B [Laboratoire des Solutions Solides, Faculty of Physics (USTHB) BP 32 16111, Algiers (Algeria); Bouguelia, A [Laboratoire de Stockage et de Valorisation des Energies Renouvelables, Faculty of Chemistry (USTHB) BP 32 16111, Algiers (Algeria); Kadi-Hanifi, M [Laboratoire des Solutions Solides, Faculty of Physics (USTHB) BP 32 16111, Algiers (Algeria); Trari, M [Laboratoire de Stockage et de Valorisation des Energies Renouvelables, Faculty of Chemistry (USTHB) BP 32 16111, Algiers (Algeria)

    2006-09-20

    The transport properties of oxygen-deficient perovskite SrPbO{sub 3-{delta}} with mixed lead valency were investigated down to 4.2 K. The small {delta}-value (0.059), determined from iodometry, is due to the inert lone pair Pb{sup 2+} that does not enjoy regular octahedral coordination in spite of collective electron behaviour. The oxide exhibits a temperature-independent magnetic susceptibility consistent with itinerant electrons. The sign of carriers like polarons is that of n-type conductivity coming from the balance charge via oxygen extraction. The thermal variation of conductivity and thermopower reveal the existence of an energy gap. The conduction mechanism occurs by polaron hopping in conformity with small activation energy. The metal-insulating transition seems to be of Anderson type, resulting from the disorder of oxygen vacancies. At low temperature, the conductivity was fitted to a variable range hopping ln (1/ {rho}) {proportional_to} T{sup -4}. A comparison with SrSnO{sub 3} will be reported. The covalency of Sn-O raises the antibonding conduction state of 5s parentage and increases the forbidden gap from 1.78 to 3.30 eV.

  18. The physical properties of oxygen-deficient perovskite SrPbO(3-δ).

    Science.gov (United States)

    Hadjarab, B; Bouguelia, A; Kadi-Hanifi, M; Trari, M

    2006-09-20

    The transport properties of oxygen-deficient perovskite SrPbO(3-δ) with mixed lead valency were investigated down to 4.2 K. The small δ-value (0.059), determined from iodometry, is due to the inert lone pair Pb(2+) that does not enjoy regular octahedral coordination in spite of collective electron behaviour. The oxide exhibits a temperature-independent magnetic susceptibility consistent with itinerant electrons. The sign of carriers like polarons is that of n-type conductivity coming from the balance charge via oxygen extraction. The thermal variation of conductivity and thermopower reveal the existence of an energy gap. The conduction mechanism occurs by polaron hopping in conformity with small activation energy. The metal-insulating transition seems to be of Anderson type, resulting from the disorder of oxygen vacancies. At low temperature, the conductivity was fitted to a variable range hopping [Formula: see text]. A comparison with SrSnO(3) will be reported. The covalency of Sn-O raises the antibonding conduction state of 5s parentage and increases the forbidden gap from 1.78 to 3.30 eV.

  19. Indication of Negative Triaxial Deformation in the Very Neutron-Deficient Odd-A Re Isotopes

    Institute of Scientific and Technical Information of China (English)

    周小红; 许甫荣; 郑勇; 张玉虎

    2003-01-01

    For the 9/2-[514] bands in light odd-A Re isotopes, the energy signature splitting and its relation with the signature dependence of M1 transition matrix elements are investigated in connection with the deviation of nuclear shape from axial symmetry. By comparing the energy signature splittings and relative magnetic transition rates between the experimental values and the theoretical calculations assuming axially symmetric shapes, it is found that discrepancies increase with the decreasing neutron number. These discrepancies strongly suggest an appreciable negative γ deformation for the very neutron-deficient odd-A Re isotopes.

  20. β-decay properties of neutron-deficient Pt, Hg, and Pb isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Sarriguren, P., E-mail: p.sarriguren@csic.es [Instituto de Estructura de la Materia, IEM-CSIC, Serrano 123, E-28006 Madrid (Spain); Boillos, J. M. [Instituto de Estructura de la Materia, IEM-CSIC, Serrano 123, E-28006 Madrid (Spain); Universidad de Santiago de Compostela, 15706 Santiago de Compostela (Spain); Moreno, O. [Center for Theoretical Physics, Laboratory for Nuclear Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Moya de Guerra, E. [Departamento de Física Atómica, Molecular y Nuclear, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, E-28040 Madrid (Spain)

    2015-10-15

    Neutron-deficient isotopes in the lead region are well established examples of the shape coexistence phenomenon in nuclei. In this work, bulk and decay properties, including deformation energy curves, charge mean square radii, Gamow-Teller (GT) strength distributions, and β-decay half-lives, are studied in neutron-deficient Pt, Hg, and Pb isotopes. The nuclear structure involved is described microscopically from deformed quasiparticle random-phase approximation calculations with residual interactions in both particle-hole and particle-particle channels, performed on top of a self-consistent deformed quasiparticle Skyrme Hartree-Fock basis. The sensitivity to deformation of the GT strength distributions in those isotopes is proposed as an additional complementary signature of the nuclear shape. The β-decay half-lives resulting from the GT strength distributions are compared to experiment to demonstrate the ability of the method.

  1. Probing shape coexistence in neutron-deficient $^{72}$Se via low-energy Coulomb excitation

    CERN Multimedia

    We propose to study the evolution of nuclear structure in neutron-­deficient $^{72}$Se by performing a low-­energy Coulomb excitation measurement. Matrix elements will be determined for low-­lying excited states allowing for a full comparison with theoretical predictions. Furthermore, the intrinsic shape of the ground state, and the second 0$^{+}$ state, will be investigated using the quadrupole sum rules method.

  2. Four-Quasiparticle High-K States in Neutron-Deficient Lead and Polonium Nuclei

    Science.gov (United States)

    Shi, Yue; Xu, Furong

    2012-06-01

    Configuration-constrained potential energy surface calculations have been performed to investigate four-quasiparticle high-K configurations in neutron-deficient lead and polonium isotopes. A good agreement between the calculations and the experimental data has been found for the excitation energy of the observed Kπ = 19- state in 188Pb. Several lowly excited high-K states are predicted, and the large oblate deformation and low energy indicate high-K isomerism in these nuclei.

  3. Ground-state properties and symmetry energy of neutron-rich and neutron-deficient Mg isotopes

    CERN Document Server

    Gaidarov, M K; Antonov, A N; de Guerra, E Moya

    2015-01-01

    A comprehensive study of various ground-state properties of neutron-rich and neutron-deficient Mg isotopes with $A$=20-36 is performed in the framework of the self-consistent deformed Skyrme-Hartree-Fock plus BCS method. The correlation between the skin thickness and the characteristics related with the density dependence of the nuclear symmetry energy is investigated for this isotopic chain following the theoretical approach based on the coherent density fluctuation model and using the Brueckner energy-density functional. The results of the calculations show that the behavior of the nuclear charge radii and the nuclear symmetry energy in the Mg isotopic chain is closely related to the nuclear deformation. We also study, within our theoretical scheme, the emergence of an "island of inversion" at neutron-rich $^{32}$Mg nucleus, that was recently proposed from the analyses of spectroscopic measurements of $^{32}$Mg low-lying energy spectrum and the charge rms radii of all magnesium isotopes in the $sd$ shell.

  4. Isomers of astrophysical interest in neutron-deficient nuclei at masses A=81,85 and 86

    Energy Technology Data Exchange (ETDEWEB)

    Kankainen, A.; Huang, W.; Huikari, J.; Jokinen, A.; Nieminen, A.; Penttilae, H.; Rinta-Antila, S.; Aeystoe, J. [University of Jyvaeskylae, Department of Physics (Finland); Vorobjev, G.K.; Novikov, Yu.N. [St. Petersburg State University (Russian Federation); Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Eliseev, S.A. [Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); GSI, Darmstadt (Germany); Popov, A.V.; Seliverstov, D.M. [Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Schatz, H. [Michigan State University, East Lansing, MI (United States); Suslov, Yu.P. [St. Petersburg State University (Russian Federation)

    2005-09-01

    Decay properties of neutron-deficient exotic nuclei close to A=80 have been investigated at the IGISOL facility. The studied nuclei, {sup 81}Y, {sup 81}Sr, {sup 81m}Kr, {sup 85}Nb, {sup 85}Zr, {sup 86}Mo and {sup 86}Nb, were produced by a {sup 32}S beam from the Jyvaeskylae isochronous cyclotron on {sup 54}Fe and {sup nat}Ni targets. The internal conversion coefficient for a 190.5 keV isomeric transition in {sup 81m}Kr has been measured and the internal transition rate has been determined. The internal transition rate has been used to estimate a neutrino capture rate on {sup 81}Br, which yields a log ft of 5.13{+-}0.09 for the reaction {sup 81}Br({nu},e{sup -}){sup 81m}Kr. A new isomer with a half-life of 3.3{+-}0.9 s has been observed in {sup 85}Nb. The existence of an earlier reported isomer with a half-life of 56 s in {sup 86}Nb has not been confirmed. (orig.)

  5. Oxygen Stoichiometry in Cation Deficient (La,Sr)_{1-z}MnO_3 SOFC Cathode Materials

    DEFF Research Database (Denmark)

    Zachau-Christiansen, Birgit; Jacobsen, Torben; Skaarup, Steen

    1997-01-01

    The variation of oxygen stoichiometry with oxygen partial pressure is determined for perovskites, ABO3, with the general composition: (La1-xSrx)_{1-z}MnO_{3+y}. The measurements are performed as linear sweep voltammetry on an oxygen pumping cell, where the oxygen partial pressure is controlled...... by the imposed potential.It is found that the oxygen stoichiometry and hence the defect chemistry is different whether A-site charge deficiency is established by Sr-doping or by A-site vacancies. Furthermore,A-site deficient lanthanum strontium manganates expel a secondary phase of manganese oxide when exposed...

  6. Deformation and mixing of co-existing shapes in the neutron-deficient polonium isotopes

    CERN Document Server

    AUTHOR|(CDS)2078559; Huyse, Mark

    The neutron-deficient polonium isotopes, with only 2 protons outside the Z = 82 shell closure, are situated in an interesting region of the nuclear chart. In the neighboring lead (Z = 82) and mercury (Z = 80) isotopes, experimental and theoretical efforts identified evidence of shape coexistence. Shape coexistence is the remarkable phenomenon in which two or more distinct types of deformation occur in states of the same angular momentum and similar excitation energy in a nucleus. The neutron-deficient polonium isotopes have also been studied intensively, experimentally as well as theoretically. The closed neutron-shell nucleus 210Po (N = 126) manifests itself as a two-particle nucleus where most of the excited states can be explained by considering the degrees of freedom of the two valence protons outside of 208Pb. The near-constant behavior of the yrast 2+1 and 4+1 states in the isotopes with mass 200 ≤ A ≤ 208 can be explained by coupling the two valence protons to a vibrating lead core. 200Po seems to ...

  7. Laser-assisted decay and optical spectroscopy studies of neutron-deficient thallium isotopes

    CERN Document Server

    Van Beveren, Céline; Huyse, Mark

    The neutron-deficient thallium isotopes with one proton less than the Z = 82 shell closure, are situated in an interesting region of the nuclear chart, notorious for intruder states and shape coexistence. Shape coexistence is the remarkable phenomenon in which two or more distinct types of deformation occur at low energy in the same atomic nucleus. Shape coexistence has been studied intensively, experimentally as well as theoretically in different nuclei in the light-lead region and the isomerism in the thallium isotopes was among the first indications of this phenomenon. Different shapes, whose structure has been linked to specific proton orbitals above and below the Z = 82 shell closure, are present at low energy in the neutron-deficient odd-mass thallium nuclei. In the odd-odd nuclei, the coupling of an unpaired proton and unpaired neutron gives rise to multiplets of low-lying states from which some can be isomeric. Since thallium has one proton missing in the major proton shell, and when approaching neutr...

  8. Multi-quasiparticle {gamma}-band structure in neutron-deficient Ce and Nd isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Sheikh, J.A. [Physics Division, Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, TN 37831 (United States); Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996 (United States); Department of Physics, University of Kashmir, Srinagar, 190 006 (India); Bhat, G.H. [Department of Physics, University of Kashmir, Srinagar, 190 006 (India); Palit, R.; Naik, Z. [Tata Institute of Fundamental Research, Colaba, Mumbai, 400 005 (India); Sun, Y. [Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996 (United States); Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)], E-mail: sunyang@sjtu.edu.cn

    2009-06-01

    The newly developed multi-quasiparticle triaxial projected shell model approach is employed to study the high-spin band structures in neutron-deficient even-even Ce- and Nd-isotopes. It is observed that {gamma}-bands are built on each intrinsic configuration of the triaxial mean-field deformation. Due to the fact that a triaxial configuration is a superposition of several K-states, the projection from these states results in several low-lying bands originating from the same intrinsic configuration. This generalizes the well-known concept of the surface {gamma}-oscillation in deformed nuclei based on the ground-state to {gamma}-bands built on multi-quasiparticle configurations. This new feature provides an alternative explanation on the observation of two I=10 aligning states in {sup 134}Ce and both exhibiting a neutron character.

  9. Multi-Quasiparticle Gamma-Band Structure in Neutron-Deficient Ce and Nd Isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Sheikh, Javid [ORNL; Bhat, G. H. [University of Kashmir, Srinagar, India; Palit, R. [Tata Institute of Fundamental Research, Mumbai, India; Naik, Z. [Tata Institute of Fundamental Research, Mumbai, India; Sun, Y. [Shanghai Jiao Tong University, Shanghai

    2009-01-01

    The newly developed multi-quasiparticle triaxial projected shell-model approach is employed to study the high-spin band structures in neutron-deficient even-even Ce and Nd isotopes. It is observed that gamma bands are built on each intrinsic configuration of the triaxial mean-field deformation. Due to the fact that a triaxial configuration is a superposition of several K states, the projection from these states results in several low-lying bands originating from the same intrinsic configuration. This generalizes the well-known concept of the surface gamma oscillation in deformed nuclei based on the ground state to gamma bands built on multi-quasiparticle configurations. This new feature provides an alternative explanation on the observation of two I=10 aligning states in ^{134}Ce and both exhibiting a neutron character.

  10. Structure Refinement of (Sr,BaNb2O6 Ceramic Powder from Neutron and X-Rays Diffraction Data

    Directory of Open Access Journals (Sweden)

    J.G. Carrio

    2002-03-01

    Full Text Available The structure of polycrystalline strontium barium niobate at room temperature was refined by the Rietveld method. Sintered ceramic samples were used to collect powder neutron and X-ray diffraction data. The ratio Sr/Ba ~ 64/36 was found from the initial batch composition Sr0.61Ba0.39Nb2O6, corroborating with the quantitative X-ray dispersive spectroscopy (EDS measurements. The structure is tetragonal with cell parameters a, b = 12.4504(3 Å and c = 3.9325(1 Å and space group P4bm. It was not necessary to introduce any positional disorder for the oxygen atoms. Cation Nb+5 displacements not parallel to the c direction are presented, which can influence the behavior of the ferroelectric properties.

  11. Microscopic study of low-lying yrast spectra and deformation systematics in neutron-rich 98−106Sr isotopes

    Indian Academy of Sciences (India)

    Anil Chandan; Suram Singh; Arun Bharti; S K Khosa

    2009-10-01

    Variation-after-projection (VAP) calculations in conjunction with Hartree–Bogoliubov (HB) ansatz have been carried out for = 98–106 strontium isotopes. In this framework, the yrast spectra with ≥ 10+, (2) transition probabilities, quadrupole deformation parameter and occupation numbers for various shell model orbits have been obtained. The results of the calculation for yrast spectra give an indication that it is important to include the hexadecapole–hexadecapole component of the two-body interaction for obtaining various nuclear structure quantities in Sr isotopes. Besides this, it is also found that the simultaneous polarization of 3/2 and 5/2 proton subshells is a significant factor in making a sizeable contribution to the deformation in neutron-rich Sr isotopes.

  12. Measurements of competing structures in neutron-deficient Pb isotopes by employing Coulomb excitation

    CERN Multimedia

    Bastin, B; Kruecken, R; Larsen, A; Rahkila, P J; Srebrny, J; Clement, E; Wadsworth, R; Syed naeemul, H; Peura, P J; Siem, S; Hadynska-klek, K; Habs, D; Napiorkowski, P J; Diriken, J V J; Iwanicki, J S

    Coulomb excitation measurements to study the shape coexistence and quadrupole collectivity of the low-lying levels in neutron-deficient Pb nuclei are proposed. Even-mass $^{188−192}$Pb nuclei will be post-accelerated at REX-ISOLDE in order to measure transition probabilities and quadrupole moments for the first excited states. In combination with results obtained in lifetime measurements, this will allow the sign of the quadrupole deformation parameter to be extracted for the first time for 2$^{+}$ states in the even-mass $^{188−192}$Pb nuclei.

  13. In-beam studies of very neutron-deficient heavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Julin, R.; Greenlees, P.T.; Helariutta, K.; Jones, P.; Juutinen, S.; Leppaenen, A.P.; Kankaanpaeae, H.; Keenan, A.; Kettunen, H.; Kuusiniemi, P.; Leino, M.; Muikku, M.; Nieminen, P.; Pakarinen, J.; Rahkila, P.; Uusitalo, J. [Department of Physics, University of Jyvaeskylae, P.O. Box 35 (JYFL), FIN-40351 Jyvaeskylae (Finland); Joss, D.T.; Williams, S.J. [School of Sciences, Staffordshire University, Staffordshire (United Kingdom); Jenkins, D.G.; Kelsall, N.S. [Department of Physics, University of York, York (United Kingdom); Wadsworth, R.; Hauschild, K.; Huerstel, A.; Korten, W.; Le Coz, Y.; Andreyev, A.N.; Van Duppen, P.; Huyse, M.; Van de Vel, K.; Moore, C.J.; O' Leary, C.D.; Page, R.D.; Taylor, M.J.; Reviol, W.; Smith, M.B.

    2002-10-01

    The JYFL gas-filled recoil separator RITU, combined with Ge detector arrays and a SACRED magnetic solenoid spectrometer, has been successfully employed in recoil-decay-tagging (RDT) experiments in order to probe structures of very neutron-deficient heavy nuclei. The present contribution focuses on the light Pb region where the new data extend the systematics of shape-coexisting yrast states towards the proton dripline. Similarities between band structures and their relation to possible multi-particle multi-hole intruder excitations will be discussed. (orig.)

  14. β Decay in the Region of Neutron-deficient {sup 69,70,71}Kr

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, A.M., E-mail: ARogers@lbl.gov [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Lawrence Berkeley National Laboratory, Berkeley, CA, 94720 (United States); Giovinazzo, J. [Centre d' Etudes Nucléaires de Bordeaux-Gradignan, Université Bordeaux 1, UMR 5797 CNRS/IN2P3, Chemin du Solarium, BP 120, F-33175, Gardignan Cedex (France); Lister, C.J. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Blank, B.; Canchel, G. [Centre d' Etudes Nucléaires de Bordeaux-Gradignan, Université Bordeaux 1, UMR 5797 CNRS/IN2P3, Chemin du Solarium, BP 120, F-33175, Gardignan Cedex (France); Clark, J.A. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); France, G. de; Grévy, S. [GANIL CEA/DSM-CNRS/IN2P3, Boulevard Henri Becquerel, BP55027, 14076 CEAN Cedex 5 (France); Gros, S.; McCutchan, E.A. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Oliveira Santos, F. de [GANIL CEA/DSM-CNRS/IN2P3, Boulevard Henri Becquerel, BP55027, 14076 CEAN Cedex 5 (France); Savard, G.; Seweryniak, D. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Stefan, I.; Thomas, J.-C. [GANIL CEA/DSM-CNRS/IN2P3, Boulevard Henri Becquerel, BP55027, 14076 CEAN Cedex 5 (France)

    2014-06-15

    Decay spectroscopy was performed for neutron-deficient nuclei ranging from zinc to krypton with isospin −3/2 ≤T{sub z}≤0. Measurements of correlated β-delayed protons allowed us to determine the isobaric analog states fed from the decay of {sup 65}Se and {sup 69}Kr, constraining the spin of the {sup 69}Kr ground state. Preliminary results regarding the half lives for the T{sub z}=−1 systems, relevant to the rapid proton capture (rp) process, are discussed.

  15. Further studies of neutron-deficient Sn-isotopes using REX-ISOLDE

    CERN Multimedia

    Larsen, A; Syed naeemul, H; Siem, S

    2007-01-01

    Encouraged by the committee to submit the latter part of our latest addendum to experiment IS418 under a new heading this proposal focuses on the second physics case mentioned there. We propose to use Coulomb excitation of odd mass neutron-deficient Sn isotopes to study some dominantly "one quasi-particle" states in these nuclei. Due to spin selection rules these states are difficult to populate following either $\\beta$-decay or in a cascade after a fusion-evaporation reactions, whereas the excitation from the ground-state is of E2 character for some of the most interesting cases.

  16. Observation of new neutron-deficient isotopes with Z≥92 in multinucleon transfer reactions

    Directory of Open Access Journals (Sweden)

    H.M. Devaraja

    2015-09-01

    Full Text Available In deep inelastic multinucleon transfer reactions of 48Ca + 248Cm we observed about 100 residual nuclei with proton numbers between Z=82 and Z=100. Among them, there are five new neutron-deficient isotopes: 216U, 219Np, 223Am, 229Am and 233Bk. As separator for the transfer products we used the velocity filter SHIP of GSI while the isotope identification was performed via the α decay chains of the nuclei. These first results reveal that multinucleon transfer reactions together with here applied fast and sensitive separation and detection techniques are promising for the synthesis of new isotopes in the region of heaviest nuclei.

  17. Production and identification of new neutron-deficient isotope 235Am in region of transuranium

    Institute of Scientific and Technical Information of China (English)

    甘再国; 郭俊盛; 刘洪业; 石立军; 杨维凡; 牟万统; 郭天瑞; 方克明; 沈水法; 袁双贵; 张学谦; 秦芝; 马瑞昌; 钟纪泉; 罗亦孝; 王书鸿; 孔登明; 乔际民

    1997-01-01

    A new transuranium neutron-deficient isotope 235Am was produced by 35 MeV proton to bombard the rare radioactive 238Pu target The products were transported and collected by the He-jet system. The Am isotopes were separated and purified by radiochemtstry method and the γ-ray, X-ray and γ-X(γ) coincidence of the samples was measured The synthesis of 235 Am was definitely identified Its measured half-life is (15±5) mom.

  18. Study of oblate nuclear shapes and shape coexistence in neutron-deficient rare earth isotopes

    CERN Multimedia

    Guttormsen, M S; Reiter, P; Larsen, A; Korten, W; Clement, E; Siem, S; Renstrom, T; Buerger, A; Jenkins, D G

    We propose to investigate nuclear shapes and shape coexistence in neutron-deficient rare earth nuclei below the N=82 shell closure at the ISOLDE facility by employing Coulomb excitation of Nd, Sm, Gd, and Dy beams from the REX accelerator and the Miniball experiment. Nuclear shapes are expected to change rapidly in this region of the nuclear chart. The measurement of electric quadrupole moments of excited states and the transition rates between them serves as a stringent test of theoretical models and effective nucleon-nucleon interactions.

  19. New neutron-deficient isotopes of barium and rare-earth elements

    CERN Document Server

    Bogdanov, D D; Karnaukhov, V A; Petrov, L A; Plochocki, A; Subbotin, V G; Voboril, J

    1976-01-01

    The authors present an investigation of the short-lived neutron- deficient isotopes of barium and rare-earth elements. By using the BEMS-2 isotope separator on a heavy ion beam, 19 new isotopes were produced with mass numbers ranging from 117 to 138. Five of these (/sup 117/Ba, /sup 129,131/Nd and /sup 133,135/Sm) turned out to be delayed proton emitters. The beta -decay probabilities for the new isotopes have been analyzed in terms of the beta -strength function. An analysis of the proton spectrum shape has been performed using the statistical model for delayed proton emission.

  20. Shape transition and coexistence in neutron-deficient rare earth isotopes

    CERN Multimedia

    We propose to study spectroscopic quadrupole moments of excited states and electromagnetic transition rates between them in the neutron-deficient rare earth nuclei $^{140}$Sm and $^{142}$Gd using projectile Coulomb excitation at energies of 4.7 MeV per nucleon. The rare earth nuclei below the N=82 shell closure form one of the few regions of the nuclear chart where oblate shapes are expected to occur near the ground state. Nuclear shapes are expected to change rapidly in this region, with coexistence of oblate and prolate shapes in some nuclei. The measurement of electromagnetic matrix elements represents therefore a particularly sensitive test of theoretical nuclear structure models.

  1. Collinear antiferromagnetism in trigonal SrMn2As2 revealed by single-crystal neutron diffraction

    Science.gov (United States)

    Das, Pinaki; Sangeetha, N. S.; Pandey, Abhishek; Benson, Zackery A.; Heitmann, T. W.; Johnston, D. C.; Goldman, A. I.; Kreyssig, A.

    2017-01-01

    Iron pnictides and related materials have been a topic of intense research for understanding the complex interplay between magnetism and superconductivity. Here we report on the magnetic structure of SrMn2As2 that crystallizes in a trigonal structure (P\\bar{3}m1 ) and undergoes an antiferromagnetic (AFM) transition at {{T}\\text{N}}=118(2) K. The magnetic susceptibility remains nearly constant at temperatures T≤slant {{T}\\text{N}} with \\boldsymbol{H}\\parallel \\boldsymbol{c} whereas it decreases significantly with \\boldsymbol{H}\\parallel \\boldsymbol{a}\\boldsymbol{b} . This shows that the ordered Mn moments lie in the \\boldsymbol{a}\\boldsymbol{b} plane instead of aligning along the \\boldsymbol{c} -axis as in tetragonal BaMn2As2. Single-crystal neutron diffraction measurements on SrMn2As2 demonstrate that the Mn moments are ordered in a collinear Néel AFM phase with {{180}\\circ} AFM alignment between a moment and all nearest neighbor moments in the basal plane and also perpendicular to it. Moreover, quasi-two-dimensional AFM order is manifested in SrMn2As2 as evident from the temperature dependence of the order parameter.

  2. Neutron diffraction study of quadruple perovskite SrCu{sub 3}Fe{sub 3}O{sub 12}

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Ikuya, E-mail: i-yamada@21c.osakafu-u.ac.jp [Nanoscience and Nanotechnology Research Center, Osaka Prefecture University, 1-2 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8570 (Japan); Murakami, Makoto; Mori, Shigeo [Department of Materials Science, Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531 (Japan); Irifune, Tetsuo [Geodynamics Research Center, Ehime University, 2-5 Bunkyo-cho, Matsuyama, Ehime 790-8577 (Japan)

    2016-08-26

    The magnetic structure of the quadruple perovskite SrCu{sub 3}Fe{sub 4}O{sub 12} is studied by means of neutron powder diffraction. The magnetic diffraction peaks are observed at low temperatures below 200 K. The Rietveld refinement result suggests an antiferromagnetic alignment of Fe spin magnetic moments for SrCu{sub 3}Fe{sub 4}O{sub 12} at low temperature. The refined magnetic moment at 4 K is ∼3.5 µ{sub B}, which is larger than that of that of CeCu{sub 3}Fe{sub 4}O{sub 12} (2.3 µ{sub B}). The increase in the magnetic moment is attributed to the larger Fe{sup 3+}:Fe{sup 5+} ratio for SrCu{sub 3}Fe{sub 4}O{sub 12} (∼4:1) compared with that of CeCu{sub 3}Fe{sub 4}O{sub 12} (∼3:1).

  3. Mantid - Data Analysis and Visualization Package for Neutron Scattering and $\\mu SR$ Experiments

    CERN Document Server

    Arnold, O; Borreguero, J M; Buts, A; Campbell, S I; Chapon, L; Doucet, M; Draper, N; Leal, R Ferraz; Gigg, M A; Lynch, V E; Markvardsen, A; Mikkelson, D J; Mikkelson, R L; Miller, R; Palmen, K; Parker, P; Passos, G; Perring, T G; Peterson, P F; Ren, S; Reuter, M A; Savici, A T; Taylor, J W; Taylor, R J; Tolchenov, R; Zhou, W; Zikovsky, J

    2014-01-01

    The Mantid framework is a software solution developed for the analysis and visualization of neutron scattering and muon spin measurements. The framework is jointly developed by software engineers and scientists at the ISIS Neutron and Muon Facility and the Oak Ridge National Laboratory. The objectives, functionality and novel design aspects of Mantid are described.

  4. Mantid—Data analysis and visualization package for neutron scattering and μ SR experiments

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, O. [ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire (United Kingdom); Tessella Ltd., Abingdon, Oxfordshire (United Kingdom); Bilheux, J.C.; Borreguero, J.M. [Neutron Data Analysis and Visualization, Oak Ridge National Laboratory, Oak Ridge, TN (United States); Buts, A. [ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire (United Kingdom); Campbell, S.I. [Neutron Data Analysis and Visualization, Oak Ridge National Laboratory, Oak Ridge, TN (United States); Chapon, L. [ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire (United Kingdom); Institut Laue-Langevin, Grenoble (France); Doucet, M. [Neutron Data Analysis and Visualization, Oak Ridge National Laboratory, Oak Ridge, TN (United States); Draper, N. [ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire (United Kingdom); Tessella Ltd., Abingdon, Oxfordshire (United Kingdom); Ferraz Leal, R. [Institut Laue-Langevin, Grenoble (France); Gigg, M.A. [ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire (United Kingdom); Tessella Ltd., Abingdon, Oxfordshire (United Kingdom); Lynch, V.E. [Neutron Data Analysis and Visualization, Oak Ridge National Laboratory, Oak Ridge, TN (United States); Markvardsen, A. [ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire (United Kingdom); Mikkelson, D.J.; Mikkelson, R.L. [University of Wisconsin-Stout, Menomonie, WI (United States); Neutron Data Analysis and Visualization, Oak Ridge National Laboratory, Oak Ridge, TN (United States); Miller, R. [Computing and Computational Science Directorate, Oak Ridge National Laboratory, Oak Ridge, TN (United States); Palmen, K.; Parker, P.; Passos, G.; Perring, T.G. [ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire (United Kingdom); Peterson, P.F. [Neutron Data Analysis and Visualization, Oak Ridge National Laboratory, Oak Ridge, TN (United States); and others

    2014-11-11

    The Mantid framework is a software solution developed for the analysis and visualization of neutron scattering and muon spin measurements. The framework is jointly developed by software engineers and scientists at the ISIS Neutron and Muon Facility and the Oak Ridge National Laboratory. The objectives, functionality and novel design aspects of Mantid are described.

  5. Inelastic neutron scattering and lattice dynamics of NaNbO3 and Sr0.70Ca0.30TiO3

    Indian Academy of Sciences (India)

    S K Mishra; R Mittal; N Choudhury; S L Chaplot; D Pandey

    2008-11-01

    NaNbO3 and (Sr,Ca)TiO3 exhibit an unusual complex sequence of temperature- and pressure-driven structural phase transitions. We have carried out lattice dynamical studies to understand the phonon modes responsible for these phase transitions. Inelastic neutron scattering measurements using powder samples were carried out at the Dhruva reactor, which provide the phonon density of states. Lattice dynamical models have been developed for SrTiO3 and CaTiO3 which have been fruitfully employed to study the phonon spectra and vibrational properties of the solid solution (Sr,Ca)TiO3.

  6. Study of neutron deficient iridium isotopes by using laser spectroscopy; Etude des noyaux d'iridium deficients en neutrons par spectroscopie laser

    Energy Technology Data Exchange (ETDEWEB)

    Verney, D

    2000-12-19

    Resonance ionization spectroscopy was performed on neutron deficient iridium isotopes {sup 182-189}Ir, {sup 186}Ir{sup m} and stable isotopes {sup 191,193}Ir. Hyperfine spectra were recorded from the optical transition at 351,7 nm between the 5d{sup 7}6s{sup 2} {sup 4}F{sub 9/2} ground state and the 5d{sup 7}6s6p {sup 6}F{sub 11/2} excited state. Radioactive iridium isotopes were obtained from {beta}{sup +}/EC decay of radioactive mercury nuclei deposited on a graphite substrate. The radioactive mercury nuclei were produced at the ISOLDE facility at CERN through spallation reactions, by bombarding a molten lead target with the 1 GeV proton beam delivered by the PS-Booster. Magnetic dipole moments and spectroscopic quadrupole moments were extracted from the hyperfine spectra. The mean square charge radius variations, as deduced from the measured isotopic shift, show a sharp change between {sup 187}Ir and {sup 186}Ir{sup g}, accompanied by a sudden increase in deformation: from {beta}2 {approx} 0,16 to {beta}2 > 0, 2. These results were analysed in the framework of an axial rotor plus one or two quasiparticles. The wave functions of the osmium and platinum cores which are used in order to describe the iridium nuclei were calculated from the HF+BCS method with the Skyrme SIII effective interaction. The cores were constrained to take the deformation parameters extracted from the isotopic shift measurements. One shows then that this sudden deformation change corresponds also to a change in the proton state that describes the odd nuclei ground state or that participates in the coupling with the neutron in odd-odd nuclei. This state is identified with the {pi}3/2{sup +}[402] orbital for the smaller deformations nuclei and with the {pi}1/2{sup -}[541] orbital stemming from the h{sub 9/2} subshell for bigger deformations nuclei. (author)

  7. Structural and Magnetic Phase Coexistence in Oxygen Deficient Perovskites (Sr,Ca)FeO 2 . 5 + δ

    Science.gov (United States)

    Carlo, J. P.; Evans, M. E.; Anczarski, J. A.; Ock, J.; Boyd, K.; Pollichemi, J. R.; Leahy, I. A.; Vogel, W.; Viescas, A. J.; Papaefthymiou, G. C.

    A variety of compounds crystallize into perovskite and similar structures, making them versatile laboratories for many phenomena and applications, including multiferroicity, superconductivity, and photovoltaics. Oxygen-deficient perovskites ABOx have attracted interest for use in fuel cells and related applications due to high oxygen mobility and the possibility of charge disproportionation. Vast chemical flexibility is obtained through reductions in lattice symmetry and rotation/distortion of the BO6 octahedra, as well as ordering of oxygen vacancies. We have synthesized and studied the structural and magnetic properties of oxygen-deficient perovskites (Sr,Ca)FeO2 . 5 + δ using x-ray diffraction and Mossbauer spectroscopy. While the ideal perovskite has δ = 0.5, this requires Fe4+, and hence strongly oxidizing environments. When grown in air, Fe3+ is favored, yielding δ ~ 0. SrFeO2 . 5 + δ exhibits cubic symmetry and paramagnetism at 300K, but CaFeO2 . 5 + δ crystallizes into the orthorhombic brownmillerite structure, and is magnetically ordered at 300K. In the doped intermediaries we find coexistence of cubic/paramagnetic and orthorhombic/magnetic phases over a wide range of Ca content. Financial support from the Villanova Undergraduate Research Fellowship program and the Research Corporation for Science Advancement.

  8. Changes in the mean square charge radii and electromagnetic moments of neutron-deficient Bi isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Barzakh, A. E., E-mail: barzakh@mail.ru; Batist, L. Kh.; Fedorov, D. V.; Ivanov, V. S.; Molkanov, P. L.; Moroz, F. V.; Orlov, S. Yu.; Panteleev, V. N.; Seliverstov, M. D.; Volkov, Yu. M. [Petersburg Nuclear Physics Institute (PNPI), NRC Kurchatov Institute, Gatchina 188300 (Russian Federation)

    2015-10-15

    In-source laser spectroscopy experiments for neutron deficient bismuth isotopes at the 306.77 nm atomic transition were carried out at the IRIS (Investigation of Radioactive Isotopes on Synchrocyclotron) facility of Petersburg Nuclear Physics Institute (PNPI). New data on isotope shifts and hyperfine structure for {sup 189–198,} {sup 211}Bi isotopes and isomers were obtained. The changes in the mean-square charge radii and the magnetic moment values were deduced. Marked deviation from the nearly spherical behavior for ground states of bismuth isotopes at N < 109 is demonstrated, in contrast to the lead and thallium isotopic chains. The big isomer shift between I = 1/2 (intruder) and I = 9/2 (normal) states for odd Bi isotopes (A = 193, 195, 197) was found.

  9. Coulomb Excitation of Neutron Deficient Sn-Isotopes using REX-ISOLDE

    CERN Multimedia

    Di julio, D D; Kownacki, J M; Marechal, F; Andreoiu, C; Siem, S; Perrot, F; Van duppen, P L E; Napiorkowski, P J; Iwanicki, J S

    2002-01-01

    It is proposed to study the evolution of the reduced transition probabilities, B(E2; 0$^{+} \\rightarrow$ 2$^{+}$), for neutron deficient Sn isotopes by Coulomb excitation in inverse kinematics using REX-ISOLDE and the MINIBALL detector array. Measurements of the reduced transition matrix element for the transition between the ground state and the first excited 2$^{+}$ state in light even-even Sn isotopes provide a means to study e.g. core polarization effects in the $^{100}$Sn core. Previous attempts to measure this quantity have been carried out using the decay of isomeric states populated in fusion evaporation reactions. We thus propose to utilize the unique opportunity provided by REX-ISOLDE, after the energy upgrade to 3.1 MeV/u, to use the more model-independent approach of Coulomb excitation to measure this quantity in a number of isotopes in this region.

  10. Spectroscopy of Neutron-Deficient Nuclei Near the Z=82 Closed Shell via Symmetric Fusion Reactions

    Directory of Open Access Journals (Sweden)

    Kondev F.G.

    2013-12-01

    Full Text Available In-beam and decay-spectroscopy studies of neutron-deficient nuclei near the Z=82 shell closure were carried out using the Fragment Mass Analyzer (FMA and the Gammasphere array, in conjunction with symmetric fusion reactions and the Recoil Decay Tagging (RDT technique. The primary motivation was to study properties of 179Tl and 180Tl, and their daughter, and grand-daughter isotopes. For the first time, in-beam structures associated with 179Tl and 180Tl were observed, as well as γ rays associated with the 180Tl α decay. No long-lived isomer was identified in 180Tl, in contrast with the known systematics for the heavier odd-odd Tl isotopes.

  11. High-precision masses of neutron-deficient rubidium isotopes using a Penning trap mass spectrometer

    CERN Document Server

    Kellerbauer, A G; Beck, D; Blaum, K; Bollen, G; Guénaut, C; Herfurth, F; Herlert, A; Kluge, H J; Lunney, D; Schwarz, S; Schweikhard, L; Weber, C; Yazidjian, C

    2007-01-01

    The atomic masses of the neutron-deficient radioactive rubidium isotopes $^{74-77,79,80,83}$Rb have been measured with the Penning trap mass spectrometer ISOLTRAP. Using the time-of-flight cyclotron resonance technique, relative mass uncertainties ranging from $1.6 \\times 10^{-8}$ to $5.6 \\times 10^{-8}$ were achieved. In all cases, the mass precision was significantly improved as compared with the prior Atomic-Mass Evaluation; no significant deviations from the literature values were observed. The exotic nuclide $^{74}$Rb with a half-life of only 65 ms, is the shortest-lived nuclide on which a high-precision mass measurement in a Penning trap has been carried out. The significance of these measurements for a check of the conserved-vector-current hypothesis of the weak interaction and the unitarity of the Cabibbo-Kobayashi-Maskawa matrix is discussed.

  12. Deformation properties of the neutron-deficient ODD-A Pt and Hg nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Sauvage, J.; Libert, J.; Roussiere, B.; Verney, D.; Ibrahim, F.; Le Blanc, F.; Oms, J. [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire; Cabaret, L.; Pinard, J. [Laboratoire Aime Cotton, 91 - Orsay (France); Crawford, J.E.; Lee, J.K.P. [Physics Dept., Mc Gill University, Montreal (Canada); Genevey, J. [Institut des Sciences Nucleaires, IN2P3-CNRS, 38 - Grenoble (France); Huber, G. [Institut fur Physik der Universitat Mainz (Germany)

    2000-07-01

    Nuclear and atomic spectroscopy measurements have provided a great number of data on the neutron-deficient Pt and Hg nuclei. The odd-A Pt and Hg with A<186 have a prolate shape, the even-even isotopes have a triaxial shape while the nuclear shape of the odd-A Pt and Hg with A>186 is still an open question. The energy of the low-lying levels and the nuclear moments have been calculated in the framework of a semi-microscopic axial-rotor + I quasiparticle coupling model. The predictions are compared with the experimental data and discussed. The results strongly suggest a prolate shape for the negative-parity low-lying states of the odd-A {sup 187-191}Pt and {sup 187-193}Hg isotopes. (authors)

  13. Mass mapping of a new area of neutron-deficient suburanium nuclides

    CERN Document Server

    Novikov, Y N; Bosch, F; Falch, M; Geissel, H; Hausmann, M; Kerscher, T; Klepper, O; Kluge, H J; Kozhuharov, C; Litvinov, Y A; Löbner, K E G; Münzenberg, G; Patyk, Z; Radon, T; Scheidenberger, C; Wapstra, A H; Wollnik, H

    2002-01-01

    The masses of 64 short-lived neutron-deficient nuclides covering the element range from tungsten to uranium have been obtained for the first time. They have been evaluated by combining directly measured masses from Schottky mass spectrometry with linked experimental Q-values in alpha-decay chains. Based on these new mass data we have determined the one-proton and two-proton drip-lines as well as the size of the 'littoral shallow' of the sea of instability. No evidence of a Thomas-Ehrman shift has been found in the region of the investigated heavy nuclides. A peculiar behavior of two-proton separation energies has been observed in the lead region. The predictive power of various mass models is investigated.

  14. Alpha decay as a probe for the structure of neutron-deficient nuclei

    CERN Document Server

    Qi, Chong

    2016-01-01

    The advent of radioactive ion beam facilities and new detector technologies have opened up new possibilities to investigate the radioactive decays of highly unstable nuclei, in particular the proton emission, $\\alpha$ decay and heavy cluster decays from neutron-deficient (or proton-rich) nuclei around the proton drip line. It turns out that these decay measurements can serve as a unique probe for studying the structure of the nuclei involved. On the theoretical side, the development in nuclear many-body theories and supercomputing facilities have also made it possible to simulate the nuclear clusterization and decays from a microscopic and consistent perspective. In this article we would like to review the current status of these structure and decay studies in heavy nuclei, regarding both experimental and theoretical opportunities. We then discuss in detail the recent progress in our understanding of the nuclear $\\alpha$ formation probabilities in heavy nuclei and their indication on the underlying nuclear st...

  15. Nuclear moments of neutron-deficient iridium isotopes from laser spectroscopy

    CERN Document Server

    Verney, D; Cabaret, L A; Crawford, J; Duong, H T; Genevey, J; Huber, G; Ibrahim, F; Krieg, M; Lee, J K P; Lunney, M D; Obert, J; Oms, J; Pinard, J; Putaux, J C; Roussière, B; Sauvage, J; Sebastian, V

    2000-01-01

    Laser spectroscopy measurements have been performed on neutron- deficient iridium isotopes. The hyperfine structure and isotope shift of the optical Ir I transition 5d/sup 7/6s/sup 2/ /sup 4/F/sub 9/2/ to 5d/sup 7/6s6p /sup 6/F/sub 11/2/ at 351.5 nm have been studied for the /sup 182-189/Ir, /sup 186/Ir/sup m/ and /sup 191,193/Ir isotopes. The nuclear magnetic and quadrupole moments were obtained from the HFS measurements and the changes of the mean square charge radii from the IS measurements. A large mean square charge radius change between /sup 187/Ir and /sup 186/Ir and between /sup 186/Ir/sup m/ and /sup 186/Ir/sup g/ has been observed. (18 refs).

  16. Competition between α decay and proton radioactivity of neutron-deficient nuclei

    Science.gov (United States)

    Wang, Y. Z.; Cui, J. P.; Zhang, Y. L.; Zhang, S.; Gu, J. Z.

    2017-01-01

    The α decay and proton radioactivity half-lives of some neutron-deficient nuclei are calculated using an effective liquid drop model (ELDM). It is found that the experimental half-lives of the two decay modes and the dominant decay mode can be well reproduced by the ELDM. Moreover, the predicted penetration probabilities (P ) of proton radioactivity by the ELDM are in agreement with those by a microscopic model (MM). This allows us to make predictions on the competition of the two decay modes for nuclei whose experimental data are not available, which are useful for future measurements. In addition, the comparison between the predicted reduced proton radioactivity half-lives by the ELDM and the ones by a standard formula suggests that one is unlikely to observe large angular momentum transfers for nuclei with a very large Coulomb parameter χ . Last, we find that in most isotope chains the proton radioactivity is the dominant decay mode for nuclei that are very close to the proton drip line. But with increasing neutron number N the main decay mode is changed into α decay. With the decay energies the decay mode anomaly of 184Bi is discussed.

  17. Electron-capture delayed fission properties of neutron-deficient einsteinium nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Shaughnessy, Dawn A. [Univ. of California, Berkeley, CA (United States)

    2000-01-01

    Electron-capture delayed fission (ECDF) properties of neutron-deficient einsteinium isotopes were investigated using a combination of chemical separations and on-line radiation detection methods. 242Es was produced via the 233U(14N,5n)242Es reaction at a beam energy of 87 MeV (on target) in the lab system, and was found to decay with a half-life of 11 ± 3 seconds. The ECDF of 242Es showed a highly asymmetric mass distribution with an average pre-neutron emission total kinetic energy (TKE) of 183 ± 18 MeV. The probability of delayed fission (PDF) was measured to be 0.006 ± 0.002. In conjunction with this experiment, the excitation functions of the 233U(14N,xn)247-xEs and 233U(15N,xn)248-xEs reactions were measured for 243Es, 244Es and 245Es at projectile energies between 80 MeV and 100 MeV.

  18. Correlation between Electroresistance and Magnetoresistance in Slight Oxygen-Deficient Nd0.67Sr0.33MnO3-δ Polycrystalline Ceramics

    Institute of Scientific and Technical Information of China (English)

    YANG Chang-Ping; DENG Heng; CHEN Shun-Sheng; WANG Hao; WEN Zhen-Chao; HAN Xiu-Feng; K. B(a)rnera

    2008-01-01

    A colossal electroresistance effect is found in Nd0.67Sr0.33MnO3-δ polycrystalline ceramics with a very slight oxygen deficiency δ = 0.05. The electroresistance behaviour of Nd0.67Sr0.33MnO3-δ(δ = 0.05) displays the striking similarity to its counterpart magnetoresistance. It reveals that the boundary effect plays an important role in electroresistance and the same physical origin is likely responsible for both magnetoresistance and electroresistance effects in Nd0.67Sr0.33MnO3-δ polycrystals.

  19. Fast neutron damage studies of La/sub 1. 85/Sr/sub 0. 15/CuO/sub 4/

    Energy Technology Data Exchange (ETDEWEB)

    Sekula, S.T.; Christen, D.K.; Kerchner, H.R.; Thompson, J.R.; Boatner, L.A.; Sales, B.C.

    1987-04-01

    The effect of fast neutron damage on the superconducting transition temperature T/sub c/ and the critical current density j/sub c/ of the compound La/sub 1.85/Sr/sub 0.15/CuO/sub 4/ has been investigated. Irradiation to a fluence of 1.3 x 10/sup 18/ n/cm/sup 2/ (E > 0.1 MeV) resulted in a decrease of T/sub c/ of about 3 K while j/sub c/ at 4.2 K and H = 2 T increased by a factor of two to 1.2 x 10/sup 4/ A/cm/sup 2/.

  20. Mantid - Data Analysis and Visualization Package for Neutron Scattering and $\\mu SR$ Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, Owen [ISIS Facility, Rutherford Appleton Laboratory (ISIS); Bilheux, Jean-Christophe [ORNL; Borreguero Calvo, Jose M [ORNL; Buts, Alex [ISIS Facility, Rutherford Appleton Laboratory (ISIS); Campbell, Stuart I [ORNL; Doucet, Mathieu [ORNL; Draper, Nicholas J [ORNL; Ferraz Leal, Ricardo F [ORNL; Gigg, Martyn [ISIS Facility, Rutherford Appleton Laboratory (ISIS); Lynch, Vickie E [ORNL; Mikkelson, Dennis J [ORNL; Mikkelson, Ruth L [ORNL; Miller, Ross G [ORNL; Perring, Toby G [ORNL; Peterson, Peter F [ORNL; Ren, Shelly [ORNL; Reuter, Michael A [ORNL; Savici, Andrei T [ORNL; Taylor, Jonathan W [ORNL; Taylor, Russell J [ORNL; Zhou, Wenduo [ORNL; Zikovsky, Janik L [ORNL

    2014-11-01

    The Mantid framework is a software solution developed for the analysis and visualization of neutron scattering and muon spin measurements. The framework is jointly developed by a large team of software engineers and scientists at the ISIS Neutron and Muon Facility and the Oak Ridge National Laboratory. The objective of the development is to improve software quality, both in terms of performance and ease of use, for the the user community of large scale facilities. The functionality and novel design aspects of the framework are described.

  1. Neutron total scattering and reverse Monte Carlo study of cation ordering in Ca(x)Sr(1-x)TiO(3).

    Science.gov (United States)

    Hui, Qun; Dove, Martin T; Tucker, Matthew G; Redfern, Simon A T; Keen, David A

    2007-08-22

    We use neutron total scattering measurements with reverse Monte Carlo analysis methods incorporating an atom-swapping algorithm to identify the short-range Ca/Sr cation ordering within the Ca(x)Sr(1-x)TiO(3) solid solution (compositions x = 0.2,0.5,0.8). Our results show that nearest-neighbour pairs have a strong tendency for unlike Ca/Sr first-neighbour coordination in the x = 0.2 and 0.5 cases. In the x = 0.5 case the Ca/Sr ordering results in a structure with space group P 2(1)nm. In contrast, there is much less short-range cation ordering in the x = 0.8 case.

  2. Saturation of Deformation and Identical Bands in Very-Neutron Rich Sr Isotopes

    CERN Multimedia

    2002-01-01

    The present proposal aims at establishing nuclear properties in an isotopic chain showing unique features. These features include the saturation of ground state deformation at its onset and the existence of ground state identical bands in neighbouring nuclei with the same deformation. The measurements should help to elucidate the role played by the proton-neutron residual interaction between orbitals with large spatial overlap, i.e. $\\pi g _{9/2} \

  3. Rotational Bands of Some Neutron Deficient Odd-A Pt Isotopes in Particle-Triaxial-Rotor Model

    Institute of Scientific and Technical Information of China (English)

    WU Xian-Ming; LIU Yu-Xin

    2008-01-01

    Theoretical calculations are performed for neutron deficient Pt isotopes 177pt and 175,173,171pt in the particle-triaxial-rotor model with variable moment of inertia. The obtained energy spectra agree with experimental data quite well. The calculated results indicate that all these nuclei are in triaxial rotation with 177pt being in prolate and 175,173,171pt in oblate. Several levels are predicted for the 13/2+ band in 169pt.

  4. Shape coexistence in the neutron-deficient mercury isotopes studied through Coulomb excitation

    CERN Document Server

    Bree, Nick

    This thesis describes the analysis and results of a series of Coulomb-excitation experiments on even-even neutron-deficient mercury isotopes aimed at obtaining a more detailed description of shape coexistence. Two experimental campaigns have been undertaken in the Summer of 2007 and 2008. Pure beams of 182,184,186,188Hg were produced and accelerated at the REX-ISOLDE radioactive-beam facility, located at CERN (Geneva, Switzerland). The beams were guided to collide with a stable target to induce Coulomb excitation. The scattered particles were registered by a double-sided silicon strip detector, and the emitted gamma rays by the MINIBALL gamma-ray spectrometer. The motivation to study these mercury isotopes, focused around shape coexistence in atomic nuclei, is addressed in chapter 1, as well as an overview of the knowledge in this region of the nuclear chart. A theoretical description of Coulomb excitation is presented in the second chapter, while the third chapter describes the setup employed for the experim...

  5. Shape coexistence in neutron-deficient Pb nuclei probed by quadrupole moment measurements

    Energy Technology Data Exchange (ETDEWEB)

    Ionescu-Bujor, M. [National Institute for Physics and Nuclear Engineering, Bucharest (Romania)]. E-mail: bujor@ifin.nipne.ro; Iordachescu, A. [National Institute for Physics and Nuclear Engineering, Bucharest (Romania); Marginean, N. [National Institute for Physics and Nuclear Engineering, Bucharest (Romania); INFN, Laboratori Nazionali di Legnaro, Legnaro (Italy)] (and others)

    2007-06-28

    The spectroscopic quadrupole moments of the 11{sup -} and 12{sup +} isomers in {sup 192,194}Pb, described by the 3s{sub 1/2}{sup -2}1h{sub 9/2}1i{sub 13/2} intruder two-proton and 1i{sub 13/2}{sup 2} two-quasineutron configurations, respectively, have been determined by the method of time-differential observation of the {gamma}-ray perturbed angular distribution. The derived values are vertical bar Q{sub s} vertical bar (12{sup +},{sup 192}Pb)=0.32(4) eb, vertical bar Q{sub s} vertical bar (11{sup -},{sup 192}Pb)=2.9(3) eb and vertical bar Q{sub s} vertical bar (11{sup -},{sup 194}Pb)=3.6(4) eb. The 8{sup +} 2304 keV and 9{sup -} 2514 keV states in {sup 192}Pb have been identified as isomers, with half-lives of 3.9(3) and 3.3(2) ns, respectively. The experimental spectroscopic quadrupole moments for the 11{sup -} and 12{sup +} isomers in neutron deficient Pb nuclei have been described in the framework of the pairing plus quadrupole model. The intrinsic quadrupole moments and deformation of the 11{sup -} isomers are compared with the predictions of mean-field and interacting boson models.

  6. Deformation and mixing of coexisting shapes in neutron-deficient polonium isotopes

    Science.gov (United States)

    Kesteloot, N.; Bastin, B.; Gaffney, L. P.; Wrzosek-Lipska, K.; Auranen, K.; Bauer, C.; Bender, M.; Bildstein, V.; Blazhev, A.; Bönig, S.; Bree, N.; Clément, E.; Cocolios, T. E.; Damyanova, A.; Darby, I.; De Witte, H.; Di Julio, D.; Diriken, J.; Fransen, C.; García-Ramos, J. E.; Gernhäuser, R.; Grahn, T.; Heenen, P.-H.; Hess, H.; Heyde, K.; Huyse, M.; Iwanicki, J.; Jakobsson, U.; Konki, J.; Kröll, T.; Laurent, B.; Lecesne, N.; Lutter, R.; Pakarinen, J.; Peura, P.; Piselli, E.; Próchniak, L.; Rahkila, P.; Rapisarda, E.; Reiter, P.; Scheck, M.; Seidlitz, M.; Sferrazza, M.; Siebeck, B.; Sjodin, M.; Tornqvist, H.; Traykov, E.; Van De Walle, J.; Van Duppen, P.; Vermeulen, M.; Voulot, D.; Warr, N.; Wenander, F.; Wimmer, K.; Zielińska, M.

    2015-11-01

    Coulomb-excitation experiments are performed with postaccelerated beams of neutron-deficient Po 196 ,198 ,200 ,202 isotopes at the REX-ISOLDE facility. A set of matrix elements, coupling the low-lying states in these isotopes, is extracted. In the two heaviest isotopes, Po,202200, the transitional and diagonal matrix elements of the 21+ state are determined. In Po,198196 multistep Coulomb excitation is observed, populating the 41+,02+ , and 22+ states. The experimental results are compared to the results from the measurement of mean-square charge radii in polonium isotopes, confirming the onset of deformation from 196Po onwards. Three model descriptions are used to compare to the data. Calculations with the beyond-mean-field model, the interacting boson model, and the general Bohr Hamiltonian model show partial agreement with the experimental data. Finally, calculations with a phenomenological two-level mixing model hint at the mixing of a spherical structure with a weakly deformed rotational structure.

  7. Coulomb excitation of $^{182-184}$ Hg: Shape coexistence in the neutron-deficient lead region

    CERN Multimedia

    We put forward a study of the interplay between individual nucleon behavior and collective degrees of freedom in the nucleus, as manifested in shape coexistence in the neutron-deficient lead region. As a first step of this experimental campaign, we propose to perform Coulomb excitation on light mercury isotopes to probe their excited states and determine transitional and diagonal E2 matrix elements, especially reducing the current uncertainties. The results from previous Coulomb excitation measurements in this mass region performed with 2.85 MeV/u beams from REX-ISOLDE have shown the feasibility of these experiments. Based on our past experience and the results obtained, we propose a detailed study of the $^{182-184}$Hg nuclei, that exhibit a pronounced mixing between 2 low-lying excited states of apparently different deformation character, using the higher energy beams from HIE-ISOLDE which are crucial to reach our goal. The higher beam energy should result in an increased sensitivity with respect to the qua...

  8. Study of the Neutron Deficient Pb and Bi Isotopes by Simultaneous Atomic- and Nuclear-Spectroscopy

    CERN Multimedia

    Kessler, T

    2002-01-01

    We propose to study systematically nuclear properties of the neutron deficient lead $^{183-189}$Pb, $^{191g}$Pb, $^{193g}$Pb and bismuth isotopes $^{188-200}$Bi by atomic spectroscopy with the ISOLDE resonance ionisation laser ion source (RILIS) combined with simultaneous nuclear spectroscopy at the detection set-up. The main focus is the determination of the mean square charge radii of $^{183-190}$Pb and $^{188-193}$Bi from which the influence of low-lying intruder states should become obvious. Also the nuclear spin and magnetic moments of ground-states and long-lived isomers will be determined unambiguously through evaluation of the hyperfine structure, and new isomers could be discovered. The decay properties of these nuclei can be measured by $\\alpha$-$\\gamma$ and $\\beta$-$\\gamma$ spectroscopy. With this data at hand, possible shape transitions around mid-shell at N$\\sim$104 will be studied. This data is crucial for the direct test of nuclear theory in the context of intruder state influence (e.g. energy ...

  9. Neutron diffraction study of the Sr 1-xBi xF 2+x solid solution quenched from 700°C : Proposition of a clustering process

    Science.gov (United States)

    Soubeyroux, J. L.; Réau, J. M.; Wahbi, M.; Sénégas, J.; Soo, Suh Kyung

    1992-07-01

    A neutron diffraction investigation of the fluorite-type Sr 1-xBi xF 2+x (0 ⩽ x ≲ 0.50) solid solution has revealed the existence of three F' F″ and F'″ interstitial flouride ions. The anionic distribution between normal and interstitial sites has been determined as a function of x. A clustering process has been proposed in Sr 1-xBi xF 2+x on the basis of neutron diffraction results and of the composition dependence of electrical properties. It consists in a progressive transformation with increasing x of 3:2:3:0 clusters into "1:0:3:0" clusters.

  10. Proton diffusion in SrZr{sub 0.95}Y{sub 0.05}O{sub 3} observed by quasielastic neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Sata, Noriko; Ishigame, Mareo [Tohoku Univ., Sendai (Japan). Research Inst. for Scientific Measurements; Shin, Shik; Shibata, Kaoru

    1999-11-01

    Proton diffusion was observed in Y-dopedSrZrO{sub 3} ceramics above 500 deg C by quasielastic neutron scattering. The line width of the quasielastic component varies with energy transfer Q and temperature. The temperature dependence is well elucidated by the thermal activation-type proton migration with activation energy of 0.2eV. The observed hopping distance was 1.7A, which is comparable to one of the distances between two proton sites. (author)

  11. AC Electrical Conduction of Cr-Doped SrTiO3 Thin Films with an Oxygen-Deficient Interface Layer

    Science.gov (United States)

    Phan, Bach Thang; Eom, Ki Tae; Lee, Jaichan

    2017-06-01

    The ac electrical conduction of Cr-doped SrTiO3 thin films with an oxygen-deficient interface layer was investigated as a function of temperature and frequency. The Cr-doped SrTiO3 (Cr-STO) thin films with an ultra-thin (˜2 nm) oxygen-deficient layer inserted between the top electrode and the Cr-STO layer exhibited two ac conduction mechanisms, i.e., variable-range hopping and small-polaron hopping conduction, accompanied by a relaxation process. Since high oxygen deficiency induces large lattice distortion in the depletion layer, the first relaxation process occurs at low frequencies in the thin oxygen depletion layer Cr-SrTiO3- δ , and the corresponding conduction behavior follows the small-polaron tunneling model. In the high frequency range, an additional relaxation process is involved and is associated with the variable-range hopping between the localized states in the band gap of the thick Cr-SrTiO3 layer.

  12. Charge localization in oxidized Pb2Sr2Y0.5Cu308+8 studies by electron and neutron powder diffraction

    DEFF Research Database (Denmark)

    Iversen, M.H.; Jørgensen, J.E.; Andersen, N.H.

    1998-01-01

    Oxidized Pb2Sr2Y0.5Ca0.5Cu3O8+delta was studied by electron diffraction and neutron powder diffraction. The electron diffraction diagrams showed a doubling along the b-axis and a quadruplication along the a-axis indicating that the excess oxygen is incorporated into the structure in an ordered wa...... of superconductivity in the oxidized compound. (C) 1998 Elsevier Science B.V.......Oxidized Pb2Sr2Y0.5Ca0.5Cu3O8+delta was studied by electron diffraction and neutron powder diffraction. The electron diffraction diagrams showed a doubling along the b-axis and a quadruplication along the a-axis indicating that the excess oxygen is incorporated into the structure in an ordered way....... The oxygen content was determined from refinement of the neutron data and delta = 1.2(1) was obtained. Calculation of bond valency sums for the cations shows that the bond valency sum for Cu in the CuO2 layers in Pb2Sr2Y0.5Ca0.5Cu3O8 decreases when the compound is oxidized, thereby explaining the lack...

  13. Knockdown expression and hepatic deficiency reveal anatheroprotective role for SR-BI in liver and peripheral tissues

    Energy Technology Data Exchange (ETDEWEB)

    Huby, Thierry; Doucet, Chantal; Dachet, Christiane; Ouzilleau,Betty; Ueda, Yukihiko; Afzal, Veena; Rubin, Edward; Chapman, M. John; Lesnik, Philippe

    2006-07-18

    Scavenger receptor SR-BI has been implicated inHDL-dependent atheroprotective mechanisms. We report the generation of anSR-BI conditional knockout mouse model in which SR-BI gene targeting byloxP site insertion produced a hypomorphic allele (hypomSR-BI).Attenuated SR-BI expression in hypomSR-BI mice resulted in 2-foldelevation in plasma total cholesterol (TC) levels. Cre-mediated SR-BIgene inactivation of the hypomorphic SR-BI allele in hepatocytes(hypomSR-BI-KOliver) was associated with high plasma TC concentrations,increased plasma free cholesterol/TC (FC/TC) ratio, and alipoprotein-cholesterol profile typical of SR-BI-/- mice. Plasma TClevels were increased 2-fold in hypomSR-BI and control mice fed anatherogenic diet, whereas hypomSR-BI-KOliver and SR-BI-/- mice developedsevere hypercholesterolemia due to accumulation of FC-rich, VLDL-sizedparticles. Atherosclerosis in hypomSR-BI mice was enhanced (2.5-fold)compared with that in controls, but to a much lower degree than inhypomSR-BI-KOliver (32-fold) and SR-BI-/- (48-fold) mice. The lattermodels did not differ in either plasma lipid levels or in the capacity ofVLDL-sized lipoproteins to induce macrophage cholesterol loading.However, reduced atherosclerosis in hypomSR-BI-KOliver mice wasassociated with decreased lesional macrophage content as compared withthat in SR-BI-/- mice. These data imply that, in addition to its majoratheroprotective role in liver, SR-BI may exert an antiatherogenic rolein extrahepatic tissues.

  14. The effect of La deficiency on structure and magnetic properties of La0.9-xSr0.1MnO3

    Energy Technology Data Exchange (ETDEWEB)

    Kameli, P. [Department of Physics, Brock University, 500 Glenridge Ave., St. Catharines, Ont., L2S 3A1 (Canada); Department of Physics, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of); Salamati, H. [Department of Physics, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of); Sudhakar Rao, G.V. [Department of Physics, Brock University, 500 Glenridge Ave., St. Catharines, Ont., L2S 3A1 (Canada); Razavi, F.S. [Department of Physics, Brock University, 500 Glenridge Ave., St. Catharines, Ont., L2S 3A1 (Canada)]. E-mail: saar@brocku.ca

    2004-12-01

    A systematic study of the effect of La deficiency on structure, magnetic and electronic properties of ceramic samples of La0.9-xSr0.1MnO3 with a hole doping levels 0.01=deficient samples. In addition to rhombohedral structure, an orthorhombic structure was observed for La deficient level of 0.02=deficient level. All studied ceramics were found to be metallic below metal-insulator transition temperature with various magnetic phase transitions at different temperatures. These transitions were attributed to the existence of several crystal structures in these ceramic manganites.

  15. Deficiencies

    Data.gov (United States)

    U.S. Department of Health & Human Services — A list of all deficiencies currently listed on Nursing Home Compare, including the nursing home that received the deficiency, the associated inspection date,...

  16. Isomeric states in neutron-deficient A~80-90 nuclei populated in the fragmentation of Ag107

    OpenAIRE

    Garnsworthy, A.B.; Cáceres, Lucía; Estévez Aguado, María Esther; Jungclaus, Andrea; Kurtukian Nieto, Teresa; Wieland, O.

    2009-01-01

    The relativistic projectile fragmentation of a 750 MeV per nucleon beam of Ag107 was used to populate isomeric states in neutron-deficient nuclei around A=80-90. Reaction products were separated and unambiguously identified using the GSI FRagment Separator (FRS) and its ancillary detectors. At the final focal plane, the fragments were slowed from relativistic energies by means of an aluminium degrader and implanted in a passive stopper in the center of the high-efficiency, high-granularity St...

  17. DNA double-strand break induction in Ku80-deficient CHO cells following Boron Neutron Capture Reaction

    Directory of Open Access Journals (Sweden)

    Masunaga Shinichiro

    2011-09-01

    Full Text Available Abstract Background Boron neutron capture reaction (BNCR is based on irradiation of tumors after accumulation of boron compound. 10B captures neutrons and produces an alpha (4He particle and a recoiled lithium nucleus (7Li. These particles have the characteristics of high linear energy transfer (LET radiation and have marked biological effects. The purpose of this study is to verify that BNCR will increase cell killing and slow disappearance of repair protein-related foci to a greater extent in DNA repair-deficient cells than in wild-type cells. Methods Chinese hamster ovary (CHO-K1 cells and a DNA double-strand break (DSB repair deficient mutant derivative, xrs-5 (Ku80 deficient CHO mutant cells, were irradiated by thermal neutrons. The quantity of DNA-DSBs following BNCR was evaluated by measuring the phosphorylation of histone protein H2AX (gamma-H2AX and 53BP1 foci using immunofluorescence intensity. Results Two hours after neutron irradiation, the number of gamma-H2AX and 53BP1 foci in the CHO-K1 cells was decreased to 36.5-42.8% of the levels seen 30 min after irradiation. In contrast, two hours after irradiation, foci levels in the xrs-5 cells were 58.4-69.5% of those observed 30 min after irradiation. The number of gamma-H2AX foci in xrs-5 cells at 60-120 min after BNCT correlated with the cell killing effect of BNCR. However, in CHO-K1 cells, the RBE (relative biological effectiveness estimated by the number of foci following BNCR was increased depending on the repair time and was not always correlated with the RBE of cytotoxicity. Conclusion Mutant xrs-5 cells show extreme sensitivity to ionizing radiation, because xrs-5 cells lack functional Ku-protein. Our results suggest that the DNA-DSBs induced by BNCR were not well repaired in the Ku80 deficient cells. The RBE following BNCR of radio-sensitive mutant cells was not increased but was lower than that of radio-resistant cells. These results suggest that gamma-ray resistant cells have

  18. Penning-trap mass spectrometry of highly charged, neutron-rich Rb and Sr isotopes in the vicinity of $A\\approx100$

    CERN Document Server

    Simon, V V; Chowdhury, U; Eberhardt, B; Ettenauer, S; Gallant, A T; Mané, E; Simon, M C; Delheij, P; Pearson, M R; Audi, G; Gwinner, G; Lunney, D; Schatz, H; Dilling, J

    2012-01-01

    The neutron-rich mass region around $A\\approx100$ presents challenges for modeling the astrophysical $r$-process because of rapid shape transitions. We report on mass measurements using the TITAN Penning trap at TRIUMF-ISAC to attain more reliable theoretical predictions of $r$-process nucleosynthesis paths in this region. A new approach using highly charged ($q=15+$) ions has been applied which considerably saves measurement time and preserves accuracy. New mass measurements of neutron-rich $^{94,97,98}$Rb and $^{94,97-99}$Sr have uncertainties of less than 4 keV and show deviations of up to 11$\\sigma$ to previous measurements. An analysis using a parameterized $r$-process model is performed and shows that mass uncertainties for the A=90 abundance region are eliminated.

  19. The influence of fast neutron irradiation on the intra- and intergrain properties of the polycrystalline BiPbSrCaCuO system

    Science.gov (United States)

    Wiśniewski, A.; Baran, M.; Kozioł, Z.; Przysłupski, P.; Piechota, J.; Puźniak, R.; Pajaçzkowska, A.; Pȩkała, M.; Pytel, B.; Pytel, K.

    1990-09-01

    The influence of irradiation by fast neutrons with fluences from 3.3 x 10 16n/ cm2 up to 3 x 10 18n/ cm2 on the physical properties of polycrystalline Bi0.7Pb0.3SrCaCu1.8Ox was examined. Studies of DC magnetization, AC susceptibility, transport and thermoelectric power were performed. The irradiation caused a decrease of Tc, determined from the onset of diamagnetism, by as much as 31 K for a fluence of 3 x 10 18n/ cm2. A strong influence of neutron irradiation on both intra- and intergranular properties was observed. The defects within the superconducting grains created by neutrons caused an increase of the pinning forces which enhanced the critical magnetization current. A gradual decoupling of Josephson weak links with increasing neutron fluence was observed in transport and low field magnetization measurements. From the AC susceptibility measurements the irreversibility lines between the flux-creep and flux-flow regions were determined. An increase of the absolute values of thermoelectric power with rising fluence was noticed.

  20. Experimental investigation of decay properties of neutron deficient $^{116-118}$Ba isotopes and test of $^{112-115}$Ba beam counts

    CERN Multimedia

    We propose to study decay of neutron deficient isotopes $^{116-118}$Ba using Double Sided Silicon Strip Detector (DSSSD). To study delayed-proton and $\\alpha$-decay branching ratios of $^{116-118}$Ba are of special interest because of their vicinity to the proton drip line. The nuclear life-times and properties of the proton unstable states of Cs isotopes, populated through decay of $^{116-118}$Ba isotopes will be measured. In addition to that we propose beam development of $^{112-115}$Ba to study exotic decay properties of these neutron deficient nuclei and to search for super-allowed $\\alpha$-decay in future.

  1. Production cross-sections and momentum distributions of fragments from neutron-deficient 36Ar at 1.05 A.GeV

    CERN Document Server

    Caamano, M; Sümmerer, K; Benlliure, J; Casarejos, E; Geissel, H; Münzenberg, G; Pereira, J

    2004-01-01

    We have measured production cross sections and longitudinal momentum distributions of fragments from neutron-deficient 36Ar at 1.05 A.GeV. The production cross-sections show excellent agreement with the predictions of the semiempirical formula EPAX. We have compared these results, involving extremly neutron deficient nuclei, with model calculations to extract informa tion about the response of these models close to the driplines. The longitudinal momentum distributions have also been extracted and are compared with the Goldhaber and Morrissey systematics.

  2. Inelastic neutron scattering studies of phonon spectra, and simulations of pressure-induced amorphization in tungstates A W O4 (A =Ba ,Sr ,Ca , and Pb )

    Science.gov (United States)

    Goel, Prabhatasree; Gupta, M. K.; Mittal, R.; Rols, S.; Achary, S. N.; Tyagi, A. K.; Chaplot, S. L.

    2015-03-01

    Lattice dynamics and high-pressure phase transitions in A W O4 (A =Ba ,Sr ,Ca , and Pb ) have been investigated using inelastic neutron scattering experiments, ab initio density functional theory calculations, and extensive molecular dynamics simulations. The vibrational modes that are internal to W O4 tetrahedra occur at the highest energies consistent with the relative stability of W O4 tetrahedra. The neutron data and the ab initio calculations are found to be in excellent agreement. The neutron and structural data are used to develop and validate an interatomic potential model. The model is used for classical molecular dynamics simulations to study their response to high pressure. We have calculated the enthalpies of the scheelite and fergusonite phases as a function of pressure, which confirms that the scheelite to fergusonite transition is second order in nature. With increase in pressure, there is a gradual change in the A O8 polyhedra, while there is no apparent change in the W O4 tetrahedra. We found that all the four tungstates amorphize at high pressure. This is in good agreement with available experimental observations which show amorphization at around 45 GPa in BaW O4 and 40 GPa in CaW O4 . Further molecular dynamics simulations at high pressure and high temperature indicate that application of pressure at higher temperature hastens the process of amorphization. On amorphization, there is an abrupt increase in the coordination of the W atom while the bisdisphenoids around the A atom are considerably distorted. The pair-correlation functions of the various atom pairs corroborate these observations. Our observations aid in predicting the pressure of amorphization in SrW O4 and PbW O4 .

  3. The role of heparan sulfate deficiency in autistic phenotype: potential involvement of Slit/Robo/srGAPs-mediated dendritic spine formation.

    Science.gov (United States)

    Pérez, Christine; Sawmiller, Darrell; Tan, Jun

    2016-04-18

    Autism Spectrum Disorders (ASD) are the second most common developmental cause of disability in the United States. ASDs are accompanied with substantial economic and emotional cost. The brains of ASD patients have marked structural abnormalities, in the form of increased dendritic spines and decreased long distance connections. These structural differences may be due to deficiencies in Heparin Sulfate (HS), a proteoglycan involved in a variety of neurodevelopmental processes. Of particular interest is its role in the Slit/Robo pathway. The Slit/Robo pathway is known to be involved in the regulation of axonal guidance and dendritic spine formation. HS mediates the Slit/Robo interaction; without its presence Slit's repulsive activity is abrogated. Slit/Robo regulates dendritic spine formation through its interaction with srGAPs (slit-robo GTPase Activating Proteins), which leads to downstream signaling, actin cytoskeleton depolymerization and dendritic spine collapse. Through interference with this pathway, HS deficiency can lead to excess spine formation.

  4. Study of the odd-${A}$, high-spin isomers in neutron-deficient trans-lead nuclei with ISOLTRAP

    CERN Multimedia

    Herfurth, F; Blaum, K; Beck, D; Kowalska, M; Schwarz, S; Stanja, J; Huyse, M L; Wienholtz, F

    We propose to measure the excitation energy of the $\\frac{13^{+}}{2}$ isomers in the neutron-deficient isotopes $^{193,195,197}$Po with the ISOLTRAP mass spectrometer. The assignment of the low- and high-spin isomers will be made by measuring the energy of the $\\alpha$- particles emitted in the decay of purified beams implanted in a windmill system. Using $\\alpha$-decay information, it is then also possible to determine the excitation energy of the similar isomers in the $\\alpha$-daughter nuclei $^{189,191,193}$Pb, $\\alpha$-parent nuclei $^{197,199,201}$Rn, and $\\alpha$-grand-parent nuclei $^{201,203,205}$Ra. The polonium beams are produced with a UC$_{\\textrm{x}}$ target and using the RILIS.

  5. Mass measurements of very neutron-deficient Mo and Tc isotopes and their impact on rp process nucleosynthesis

    CERN Document Server

    Haettner, E; Audi, G; Blaum, K; Block, M; Eliseev, S; Fleckenstein, T; Herfurth, F; Heßberger, F P; Hofmann, S; Ketelaer, J; Ketter, J; Kluge, H -J; Marx, G; Mazzocco, M; Novikov, Yu N; Plaß, W R; Rahaman, S; Rauscher, T; Rodríguez, D; Schatz, H; Scheidenberger, C; Schweikhard, L; Sun, B; Thirolf, P G; Vorobjev, G; Wang, M; Weber, C; 10.1103/PhysRevLett.106.122501

    2011-01-01

    The masses of ten proton-rich nuclides, including the N=Z+1 nuclides 85-Mo and 87-Tc, were measured with the Penning trap mass spectrometer SHIPTRAP. Compared to the Atomic Mass Evaluation 2003 a systematic shift of the mass surface by up to 1.6 MeV is observed causing significant abundance changes of the ashes of astrophysical X-ray bursts. Surprisingly low alpha-separation energies for neutron-deficient Mo and Tc are found, making the formation of a ZrNb cycle in the rp process possible. Such a cycle would impose an upper temperature limit for the synthesis of elements beyond Nb in the rp process.

  6. Search for EC-decayed neutron-deficient actinide isotopes using gas-jet coupled JAERI-ISOL

    Energy Technology Data Exchange (ETDEWEB)

    Tsukada, Kazuaki [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-07-01

    To study the nuclear properties of unknown neutron deficient actinide isotopes which decay mainly via orbital electron capture (EC), we have developed a composite system consisting of a gas-jet transport apparatus and a thermal ion-source at the JAERI-ISOL. With this system, search for {sup 236}Am produced in the {sup 235}U({sup 6}Li, 5n) reaction has been performed. Pu KX-rays associated with the EC decay of {sup 236}Am are observed at the mass-236 fraction. The half-life of {sup 236}Am is evaluated to be 4.4min. The outline of the gas-jet coupled JAERI-ISOL system and typical performance are given. (author)

  7. Competition between α and β decays for heavy deformed neutron-deficient Pa, U, Np, and Pu isotopes

    Science.gov (United States)

    Ni, Dongdong; Ren, Zhongzhou

    2017-01-01

    The competition between α and β decays is investigated for neutron-deficient Pa, U, Np, and Pu isotopes. β+/electron-capture (EC) decay rates are calculated within the deformed quasiparticle random-phase approximation with realistic nucleon-nucleon (N N ) interactions. Contributions from allowed Gamow-Teller and Fermi transitions as well as first-forbidden transitions are considered. α -decay calculations are performed within the generalized density-dependent cluster model. Effects of differences between neutron and proton distributions and nuclear deformation are taken into account. In the calculations, Reid-93 N N interactions are used for β+/EC decays, while Michigan three-range Yukawa effective interactions, based on the G -matrix elements of Reid N N potentials, are used for α decay. The calculated β -decay half-lives show good agreement with the experimental data over a range of magnitude from 102 to 105 s. The resulting total half-lives including α and β contributions are found to be in good agreement with the experimental data, together with the α /β -decay branching ratios.

  8. Changes in the mean-square charge radii and magnetic moments of neutron-deficient Tl isotopes

    Science.gov (United States)

    Barzakh, A. E.; Batist, L. Kh.; Fedorov, D. V.; Ivanov, V. S.; Mezilev, K. A.; Molkanov, P. L.; Moroz, F. V.; Orlov, S. Yu.; Panteleev, V. N.; Volkov, Yu. M.

    2013-08-01

    In-source laser spectroscopy experiments for neutron-deficient thallium isotopes at the 276.9-nm atomic transition have been carried out at the Investigation of Radioactive Isotopes on Synchrocyclotron facility of Petersburg Nuclear Physics Institute. New data on isotope shifts and the hyperfine structure for 183-207Tl isotopes and isomers are presented. The changes in the mean-square charge radii and magnetic-moment values are deduced. It is shown that nuclear properties of Tl isotopes and isomers smoothly change at the neutron midshell and beyond without development of strong deformation in contrast to the adjacent Hg nuclei. A rather great isomer shift between I = 1/2 and I = 9/2 states for odd Tl isotopes is preserved for both sides of the previously investigated mass range. For the first time, a similar isomer shift is found for the odd-odd isotope 186Tl. The close resemblance of the charge radii isotopic behavior for the Tl and Pb ground states is demonstrated.

  9. On the Sr1−xBaxFeO2F Oxyfluoride Perovskites: Structure and Magnetism from Neutron Diffraction and Mössbauer Spectroscopy

    Directory of Open Access Journals (Sweden)

    Crisanto A. García-Ramos

    2016-11-01

    Full Text Available Four oxyfluorides of the title series (x = 0.00, 0.25, 0.50, 0.75 have been stabilized by topotactic treatment of perovskite precursors Sr1−xBaxFeO3−δ prepared by soft-chemistry procedures, yielding reactive materials that can easily incorporate a substantial amount of F atoms at moderate temperatures, thus avoiding the stabilization of competitive SrF2 and BaF2 parasitic phases. XRD and Neutron Powder Diffraction (NPD measurements assess the phase purity and yield distinct features concerning the unit cell parameters’ variation, the Sr and Ba distribution, the stoichiometry of the anionic sublattice and the anisotropic displacement factors for O and F atoms. The four oxyfluorides are confirmed to be cubic in all of the compositional range, the unit cell parameters displaying Vergard’s law. All of the samples are magnetically ordered above room temperature; the magnetic structure is always G-type antiferromagnetic, as shown from NPD data. The ordered magnetic moments are substantially high, around 3.5 μB, even at room temperature (RT. Temperature-dependent Mössbauer data allow identifying Fe3+ in all of the samples, thus confirming the Sr1−xBaxFeO2F stoichiometry. The fit of the magnetic hyperfine field vs. temperature curve yields magnetic ordering TN temperatures between 740 K (x = 0.00 and 683 K (x = 0.75. These temperatures are substantially higher than those reported before for some of the samples, assessing for stronger Fe-Fe superexchange interactions for these specimens prepared by fluorination of citrate precursors in mild conditions.

  10. Neutron scattering from the flux-line lattice in Bi2Sr2CaCu2O8+#gamma#

    DEFF Research Database (Denmark)

    Paul, D.M.; Forgan, E.M.; Cubitt, R.

    1995-01-01

    Neutron small-angle diffraction has been used to investigate the flux-line lattice structure within single crystals of the high-temperature superconductor Bi2.15Sr1.95CaCu2O8+x. The diffracted intensity goes rapidly to zero as the magnetic field or the temperature is increased. Melting at low...

  11. First Measurement of Statistical Gamma-ray Transitions in ^88Sr at TUNL via Inelastic Neutron Scattering

    Science.gov (United States)

    Carter, S.; Rusev, G.; Arnould, C.; Tornow, W.; Gooden, M.; Kelley, J. H.; Hammond, S. L.; Stevens, L.

    2011-10-01

    Predictions of the intensity distribution of γ rays emitted by product nuclei of a certain nuclear reaction are of interest for nuclear astrophysics to estimate the photon flux during a supernova as well as for applied physics for calculating radiation shielding, for instance. Furthermore, by knowing the average γ-ray spectrum for a given isotope we can predict whether the nucleus will transmute if it is exposed to a strong γ flux as the ``hot supernova-explosion scenario'' suggests. We report results for the distribution of γ rays following the ^88Sr(n,n'γ) reaction. This experiment, carried out for the first time at TUNL's FN 10 tandem, aims at measurement of the statistical γ rays and is complementary to our previous experiments on ^87Sr(n,γ) at LANSCE and ^88Sr(,') at the High Intensity γ-Ray Source Facility.

  12. Description of the shape coexistence in neutron-deficient 74,76Kr with IBM2

    Science.gov (United States)

    Zhang, DaLi; Mu, ChengFu

    2016-08-01

    The shape deformation and shape coexistence in 74,76Kr isotopes are investigated within the framework of the proton-neutron interacting boson model (IBM2). By considering the relative energy of the d proton boson to be different from that of the neutron boson, the low-lying energy spectrum is in good agreement with experimental results both qualitatively and quantitatively. In particular, the low-lying 0 2 + states associated with the shape-coexistence phenomenon are reproduced quite well. The calculated key sensitive quantities of B(E2) transition branch ratios are fairly consistent with the experimental data except for R 4. The predicated deformation parameter is very similar for the ground states in 74Kr and 76Kr, showing good agreement with the experimental result, and the calculated deformation parameter for the second 0+ state in 74Kr is close to the experimental data. The calculated results of the triaxiality parameter indicated an almost purely prolate shape for the ground state of 76Kr and a mostly prolate shape with a little triaxiality for the ground state of 74Kr. The calculations also show an oblate triaxial shape for the second 0+ state in 76Kr and maximum triaxiality for the second 0+ state in 74Kr. These results confirm the importance of the triaxial deformation for the description of such shape coexistence.

  13. The relative diffusive transport rate of SrI2 in water changes over the nanometer length scale as measured by coherent quasielastic neutron scattering.

    Science.gov (United States)

    Rubinson, Kenneth A; Faraone, Antonio

    2016-05-14

    X-ray and neutron scattering have been used to provide insight into the structures of ionic solutions for over a century, but the probes have covered distances shorter than 8 Å. For the non-hydrolyzing salt SrI2 in aqueous solution, a locally ordered lattice of ions exists that scatters slow neutrons coherently down to at least 0.1 mol L(-1) concentration, where the measured average distance between scatterers is over 18 Å. To investigate the motions of these scatterers, coherent quasielastic neutron scattering (CQENS) data on D2O solutions with SrI2 at 1, 0.8, 0.6, and 0.4 mol L(-1) concentrations was obtained to provide an experimental measure of the diffusive transport rate for the motion between pairs of ions relative to each other. Because CQENS measures the motion of one ion relative to another, the frame of reference is centered on an ion, which is unique among all diffusion measurement methods. We call the measured quantity the pairwise diffusive transport rate Dp. In addition to this ion centered frame of reference, the diffusive transport rate can be measured as a function of the momentum transfer q, where q = (4π/λ)sin θ with a scattering angle of 2θ. Since q is related to the interion distance (d = 2π/q), for the experimental range 0.2 Å(-1)≤q≤ 1.0 Å(-1), Dp is, then, measured over interion distances from 40 Å to ≈6 Å. We find the measured diffusional transport rates increase with increasing distance between scatterers over the entire range covered and interpret this behavior to be caused by dynamic coupling among the ions. Within the model of Fickian diffusion, at the longer interionic distances Dp is greater than the Nernst-Hartley value for an infinitely dilute solution. For these nm-distance diffusional transport rates to conform with the lower, macroscopically measured diffusion coefficients, we propose that local, coordinated counter motion of at least pairs of ions is part of the transport process.

  14. O deficient LaAlO3/SrTiO3(110) and (001) superlattices under hydrostatic pressure: a comparative first principles study

    KAUST Repository

    Albar, Arwa

    2017-03-17

    We compare the electronic properties of O deficient LaAlO3/SrTiO3 superlattices oriented along the (001) and (110) directions, taking into account the effect of hydrostatic compression and tension. Interfacial O vacancies turn out to be less likely in the case of the (110) orientation, with compression (tension) reducing (enhancing) the energy cost for both orientations. The presence of O vacancies results in the formation of a two-dimensional electron gas, for which we observe a distinct spatial pattern of carrier density that depends strongly on the amount of applied pressure. We clarify the interrelation between structural features and the properties of this electron gas (confinement, carrier density, and mobility).

  15. Measurements of electric quadrupole moments of neutron-deficient Au, Pt, and Ir nuclei with NMR-ON in hcp-Co

    CERN Multimedia

    Smolic, E; Hagn, E; Zech, E; Seewald, G

    2002-01-01

    The aim of the experiments is the measurement of $\\,$i) nuclear magnetic moments and electric quadrupole moments of neutron-deficient isotopes in the region Os-Ir-Pt-Au with the methods of quadrupole-interaction-resolved NMR on oriented nuclei " QI-NMR-ON " and modulated adiabatic passage on oriented nuclei " MAPON " and $\\,$ii) the magnetic hyperfine field, electric field gradient (EFG), and spin-lattice relaxation of 5d elements in ferromagnetic Fe, Ni, fcc-Co and hcp-Co.\\\\ The measurements on Au isotopes have been finished successfully. The quadrupole moments of $^{186}$Au, $^{193m}$Au, $^{195}$Au, $^{195m}$Au, $^{197m}$Au, $^{198}$Au and $^{199}$Au were determined with high precision.\\\\ For neutron-deficient Ir isotopes QI-NMR-ON measurements were performed after implantation of Hg precursors. The EFG of Ir in hcp-Co has been calibrated. Thus precise values for the spectroscopic quadrupole mo...

  16. Systematical study of high-spin rotational bands in neutron-deficient Kr isotopes by the extended projected shell model

    Science.gov (United States)

    Wu, Xin-Yi; Ghorui, S. K.; Wang, Long-Jun; Kaneko, K.; Sun, Yang

    2017-01-01

    We analyze the high-spin structure of the even-even 72-80Kr isotopes using the Projected Shell Model (PSM). With the help of the Pfaffian formulas, we have vigorously extended the quasi-particle (qp) basis of the PSM code and applied in this mass region for the first time. We consider a sufficiently large multi-qp configuration space in order to describe high-spin rotational behavior. The results show that the calculation can reproduce most of the known rotational bands with positive- or negative-parity. Moreover, some side bands appearing in the near-yrast region are predicted. The main structure for each band is discussed in terms of multi-qp configurations. The variations in moment of inertia with spin are explained in terms of successive band crossings among the 2-qp, 4-qp, 6-qp, and 8-qp states. The B (E 2) transition probabilities in these bands are also calculated. To further understand the high-spin behavior of these neutron-deficient nuclei and to confirm predictions of the present work, good high-spin data, especially for B (E 2) transitions, are called for.

  17. Oxygen vacancy clustering and electron localization in oxygen-deficient SrTiO(3): LDA + U study.

    Science.gov (United States)

    Cuong, Do Duc; Lee, Bora; Choi, Kyeong Mi; Ahn, Hyo-Shin; Han, Seungwu; Lee, Jaichan

    2007-03-16

    We find, using a local density approximation +Hubbard U method, that oxygen vacancies tend to cluster in a linear way in SrTiO(3), a prototypical perovskite oxide, accompanied by strong electron localization at the 3d state of the nearby Ti transition metal ion. The vacancy clustering and the associated electron localization lead to a profound impact on materials properties, e.g., the reduction in free-carrier densities, the appearance of characteristic optical spectra, and the decrease in vacancy mobility. The high stability against the vacancy migration also suggests the physical reality of the vacancy cluster.

  18. Cubic-tetragonal phase transition in Ca{sub 0.04}Sr{sub 0.96}TiO{sub 3}: a combined specific heat and neutron diffraction study

    Energy Technology Data Exchange (ETDEWEB)

    Gallardo, M C [Departamento de Fisica de la Materia Condensada, Instituto de Ciencia de Materiales de Sevilla, Universidad de Sevilla-CSIC, PO Box 1065, 41080 Sevilla (Spain); Becerro, A I [Departamento de Quimica Inorganica, Instituto de Ciencia de Materiales de Sevilla, Universidad de Sevilla-CSIC, Avenida Americo Vespucio s/n, 41092 Sevilla (Spain); Romero, F J [Departamento de Fisica de la Materia Condensada, Instituto de Ciencia de Materiales de Sevilla, Universidad de Sevilla-CSIC, PO Box 1065, 41080 Sevilla (Spain); Cerro, J del [Departamento de Fisica de la Materia Condensada, Instituto de Ciencia de Materiales de Sevilla, Universidad de Sevilla-CSIC, PO Box 1065, 41080 Sevilla (Spain); Seifert, F [Bayerisches Geoinstitut, Universitaet Bayreuth, 95440-Bayreuth (Germany); Redfern, S A T [Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge (United Kingdom)

    2003-01-22

    The specific heat corresponding to the tetragonal-to-cubic transition in Ca{sub 0.04}Sr{sub 0.96}TiO{sub 3} perovskite has been measured by conduction calorimetry. The order parameter of the transition has been obtained by means of neutron diffraction at low temperatures. Comparison of calorimetric data with the evolution of the order parameter indicates that this transition seems to follow a mean field Landau potential as in SrTiO{sub 3}. The linear behaviour of the excess of entropy versus temperature suggests that a 2-4 Landau potential is sufficient to describe the transition.

  19. Study of proton and 2 protons emission from light neutron deficient nuclei around A=20; Etude de l'emission proton et de deux protons dans les noyaux legers deficients en neutrons de la region A=20

    Energy Technology Data Exchange (ETDEWEB)

    Zerguerras, T

    2001-09-01

    Proton and two proton emission from light neutron deficient nuclei around A=20 have been studied. A radioactive beam of {sup 18}Ne, {sup 17}F and {sup 20}Mg, produced at the Grand Accelerateur National d'Ions Lourds by fragmentation of a {sup 24}Mg primary beam at 95 MeV/A, bombarded a {sup 9}Be target to form unbound states. Proton(s) and nuclei from the decay were detected respectively in the MUST array and the SPEG spectrometer. From energy and angle measurements, the invariant mass of the decaying nucleus could be reconstructed. Double coincidence events between a proton and {sup 17}F, {sup 16}O, {sup 15}O, {sup 14}O and {sup 18}Ne were registered to obtain excitation energy spectra of {sup 18}Ne, {sup 17}F, {sup 16}F, {sup 15}F et {sup 19}Na. Generally, the masses measures are in agreement with previous experiments. In the case of {sup 18}Ne, excitation energy and angular distributions agree well with the predictions of a break up model calculation. From {sup 17}Ne proton coincidences, a first experimental measurement of the ground state mass excess of {sup 18}Na has been obtained and yields 24,19(0,15)MeV. Two proton emission from {sup 17}Ne and {sup 18}Ne excited states and the {sup 19}Mg ground state was studied through triple coincidences between two proton and {sup 15}O, {sup 16}O and {sup 17}Ne respectively. In the first case, the proton-proton relative angle distribution in the center of mass has been compared with model calculation. Sequential emission from excited states of {sup 17}Ne, above the proton emission threshold, through {sup 16}F is dominant but a {sup 2}He decay channel could not be excluded. No {sup 2}He emission from the 1.288 MeV {sup 17}Ne state, or from the 6.15 MeV {sup 18}Ne state has been observed. Only one coincidence event between {sup 17}Ne and two proton was registered, the value of the one neutron stripping reaction cross section of {sup 20}Mg being much lower than predicted. (author)

  20. Transport properties and photo electrochemical characterization of oxygen-deficient ASnO 3- δ (A=Ca, Sr and Ba)

    Science.gov (United States)

    Zidi, N.; Omeiri, S.; Hadjarab, B.; Bouguelia, A.; Akroun, A.; Trari, M.

    2010-08-01

    The deficient stannate BaSnO 3- δ, prepared at 980 °C in sealed tube, crystallizes in an ideal perovskite structure. The oxide exhibits a blue color, the bandgap is found to be 2.65 eV and the transition is directly allowed. The non-stoichiometry could not be measured, indicating no appreciable oxygen deficiency. Nevertheless, the transport properties were found to change markedly with the heat treatment. BaSnO 3- δ behaves as degenerate SC with a conductivity σ300 K (=1.63 Ω -1 cm -1) and where the level Ef drops above mobility edge to delocalized states. The electric balance leads to a simultaneous reduction of Sn 4+ inducing n-type behavior. The thermal variation of the thermopower indicates an electron mobility μ300 K (=0.013 cm 2 V -1 s -1) thermally activated. The metal-insulating transition is considered of Anderson type due to the random potential to oxygen vacancies. A predominant variable range hopping is predicted from the non-linearity of Ln σ versus T-1 plot. The capacitance measurement ( C-2- V), measured in KOH media, shows a linear behavior from which a flat band potential Vfb (=-0.67 VSCE) and a density ND (=7.59×10 20 cm -3) are determined. The deficient stannates CaSnO 3 and SrSnO 3 are reported for a comparative purpose. The decrease of Eg is ascribed to the increase of the conduction band width when going from Ba to Ca.

  1. Transport properties and photo electrochemical characterization of oxygen-deficient ASnO{sub 3-{delta} }(A=Ca, Sr and Ba)

    Energy Technology Data Exchange (ETDEWEB)

    Zidi, N. [Laboratory of Storage and Valorization of Renewable Energies (USTHB, Faculty of Chemistry) BP 32, Algiers 16111 (Algeria); Omeiri, S. [Laboratory of Storage and Valorization of Renewable Energies (USTHB, Faculty of Chemistry) BP 32, Algiers 16111 (Algeria); Centre of Research in Physical and Chemical Analysis (C.R.A.P.C.), BP 248, RP 16004 Algiers (Algeria); Hadjarab, B. [Laboratory of Solid Solutions (USTHB, Faculty of Physics), BP 32, Algiers 16111 (Algeria); Bouguelia, A.; Akroun, A. [Laboratory of Storage and Valorization of Renewable Energies (USTHB, Faculty of Chemistry) BP 32, Algiers 16111 (Algeria); Trari, M., E-mail: labosver@gmail.co [Laboratory of Storage and Valorization of Renewable Energies (USTHB, Faculty of Chemistry) BP 32, Algiers 16111 (Algeria)

    2010-08-15

    The deficient stannate BaSnO{sub 3-{delta},} prepared at 980 deg. C in sealed tube, crystallizes in an ideal perovskite structure. The oxide exhibits a blue color, the bandgap is found to be 2.65 eV and the transition is directly allowed. The non-stoichiometry could not be measured, indicating no appreciable oxygen deficiency. Nevertheless, the transport properties were found to change markedly with the heat treatment. BaSnO{sub 3-{delta} }behaves as degenerate SC with a conductivity {sigma}{sub 300K} (=1.63 {Omega}{sup -1} cm{sup -1}) and where the level E{sub f} drops above mobility edge to delocalized states. The electric balance leads to a simultaneous reduction of Sn{sup 4+} inducing n-type behavior. The thermal variation of the thermopower indicates an electron mobility {mu}{sub 300K} (=0.013 cm{sup 2} V{sup -1} s{sup -1}) thermally activated. The metal-insulating transition is considered of Anderson type due to the random potential to oxygen vacancies. A predominant variable range hopping is predicted from the non-linearity of Ln {sigma} versus T{sup -1} plot. The capacitance measurement (C{sup -2}-V), measured in KOH media, shows a linear behavior from which a flat band potential V{sub fb} (=-0.67V{sub SCE}) and a density N{sub D} (=7.59x10{sup 20} cm{sup -3}) are determined. The deficient stannates CaSnO{sub 3} and SrSnO{sub 3} are reported for a comparative purpose. The decrease of E{sub g} is ascribed to the increase of the conduction band width when going from Ba to Ca.

  2. Neutron spectroscopy of the crystalline-electric-field in Nd{sub 1-x}Sr{sub x}MnO{sub 3} (x=0, 0.3) and PrMnO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Podelsnyak, A.; Mirmelstein, A. [Inst. for Metal Physics, Ekaterinburg (Russian Federation); Zolliker, M.; Furrer, A. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    Ln{sub 1-x}A{sub {sub x}}MnO{sub 3} manganese perovskite are of interest because of their magnetic and transport properties. Inelastic neutron scattering has been employed to search for crystalline-electric-field (CEF) transitions in Nd{sub 1-x}Sr{sub x}MnO{sub 3} (x=0, 0.3) and PrMnO{sub 3} compounds. (author) 1 fig., 3 refs.

  3. Oxygen stoichiometry and chemical expansion of Ba0.5Sr0.5Co0.8Fe0.2O3-d measured by in-situ neutron diffraction

    NARCIS (Netherlands)

    McIntosh, S.; McIntosh, Steven; Vente, Jaap F.; Haije, Wim G.; Blank, David H.A.; Bouwmeester, Henricus J.M.

    2006-01-01

    The structure, oxygen stoichiometry, and chemical and thermal expansion of Ba0.5Sr0.5Co0.8Fe0.2O3-ä (BSCF) between 873 and 1173 K and oxygen partial pressures of 1 10-3 to 1 atm were determined by in situ neutron diffraction. BSCF has a cubic perovskite structure, space group Pm3hm, across the whole

  4. Neutron spectroscopy of the crystalline-electric-field in Nd{sub 1-x}Sr{sub x}MnO{sub 3} (x=0, 0.3) and PrMnO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Podelsnyak, A.; Mirmelstein, A. [Inst. for Metal Physics, Ekaterinburg (Russian Federation); Zolliker, M.; Furrer, A. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    Ln{sub 1-x}A{sub {sub x}}MnO{sub 3} manganese perovskite are of interest because of their magnetic and transport properties. Inelastic neutron scattering has been employed to search for crystalline-electric-field (CEF) transitions in Nd{sub 1-x}Sr{sub x}MnO{sub 3} (x=0, 0.3) and PrMnO{sub 3} compounds. (author) 1 fig., 3 refs.

  5. Structural investigations of La{sub 0.8}Sr{sub 0.2}CrO{sub 3} by X-ray and neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Patra, A.K. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Nair, Sathi [Energy Conversion Materials Section, Bhabha Atomic Research Centre, Vashi Complex, Navi Mumbai 400705 (India); Sastry, P.U. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Tyagi, A.K. [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)], E-mail: aktyagi@barc.gov.in

    2009-05-05

    Effect of heat treatment on pore microstructure of La{sub 0.8}Sr{sub 0.2}CrO{sub 3} compacts was investigated by small angle neutron scattering (SANS) over the scattering wave-vector range of 0.003-3.5 nm{sup -1}. Phase and composition of the powder synthesized by gel combustion method were characterized by X-ray diffraction. Agglomerate size distribution was measured by laser diffraction. Average agglomerate size (D{sub 50}) was found to be 950 nm. Analysis of SANS data showed that pores in the green compact follow power law distribution. Pores in sintered compacts follow log-normal size distribution. Though there was decrease in porosity of the compact with increasing sintering temperature, a shift in size distribution of pores towards higher side was observed. Scaling of SANS profiles of sintered compacts using Rg as characteristic length indicated that morphological pattern of the pores in the system look nearly similar at different temperatures.

  6. Neutron scattering study of spin ordering and stripe pinning in superconducting La1.93Sr0.07CuO4

    Science.gov (United States)

    Jacobsen, H.; Zaliznyak, I. A.; Savici, A. T.; Winn, B. L.; Chang, S.; Hücker, M.; Gu, G. D.; Tranquada, J. M.

    2015-11-01

    The relationships among charge order, spin fluctuations, and superconductivity in underdoped cuprates remain controversial. We use neutron scattering techniques to study these phenomena in La1.93Sr0.07CuO4 , a superconductor with a transition temperature of Tc=20 K. At T ≪Tc we find incommensurate spin fluctuations with a quasielastic energy spectrum and no sign of a gap within the energy range from 0.2 to 15 meV. A weak elastic magnetic component grows below ˜10 K, consistent with results from local probes. Regarding the atomic lattice, we have discovered unexpectedly strong fluctuations of the CuO6 octahedra about Cu-O bonds, which are associated with inequivalent O sites within the CuO2 planes. Furthermore, we observed a weak elastic (3 3 ¯0 ) superlattice peak that implies a reduced lattice symmetry. The presence of inequivalent O sites rationalizes various pieces of evidence for charge stripe order in underdoped La2 -xSrxCuO4 . The coexistence of superconductivity with quasistatic spin-stripe order suggests the presence of intertwined orders; however, the rotation of the stripe orientation away from the Cu-O bonds might be connected with evidence for a finite gap at the nodal points of the superconducting gap function.

  7. Immunosuppression with FTY720 Reverses Cardiac Dysfunction in Hypomorphic ApoE Mice Deficient in SR-BI Expression that Survive

    Science.gov (United States)

    Luk, Fu Sang; Kim, Roy Y.; Li, Kang; Ching, Daniel; Wong, David K.; Joshi, Sunil K.; Imhof, Isabella; Honbo, Norman; Hoover, Holly; Zhu, Bo-Qing; Lovett, David H.; Karliner, Joel S.; Raffai, Robert L.

    2015-01-01

    Aims We recently reported that immunosuppression with FTY720 improves cardiac function and extends longevity in Hypomorphic ApoE mice deficient in scavenger receptor Type-BI expression, also known as the HypoE/SR-BI−/− mouse model of diet-induced coronary atherosclerosis and myocardial infarction (MI). In this study we tested the impact of FTY720 on cardiac dysfunction in HypoE/SR-BI−/− mice that survive MI and subsequently develop chronic heart failure. Methods/Results HypoE/SR-BI−/− mice were bred to Mx1-Cre transgenic mice and offspring were fed a high fat diet (HFD) for 3.5 weeks to provoke hyperlipidemia, coronary atherosclerosis and recurrent MIs. In contrast to our previous study, hyperlipidemia was rapidly reversed by inducible Cre-mediated gene repair of the HypoE allele and switching mice to a normal chow diet. Mice that survived the period of HFD were subsequently given oral FTY720 in drinking water or not, and left ventricular (LV) function was monitored using serial echocardiography for up to 15 weeks. In untreated mice, LV performance progressively deteriorated. Although FTY720 treatment did not initially prevent a decline of heart function among mice six weeks after Cre-mediated gene repair, it almost completely restored normal LV function in these mice by 15 weeks. Reversal of heart failure did not result from reduced atherosclerosis as the burden of aortic and coronary atherosclerosis actually increased to similar levels in both groups of mice. Rather, FTY720 caused systemic immunosuppression as assessed by reduced numbers of circulating T and B lymphocytes. In contrast, FTY720 did not enhance the loss of T cells or macrophages that accumulated in the heart during the HFD feeding period, but it did enhance the loss of B cells soon after plasma lipid lowering. Moreover, FTY720 potently reduced the expression of matrix metalloproteinase-2 and genes involved in innate immunity-associated inflammation in the heart. Conclusions Our data

  8. Production of very neutron-deficient isotopes near sup 1 sup 0 sup 0 Sn via reactions involving light-particle and cluster emission

    CERN Document Server

    La Commara, M; D'Onofrio, A; Gadea, A; Glogowski, M; Jarillo-Herrero, P; Belcari, N; Borcea, R; De Angelis, G; Fahlander, C; aGórska, M; Grawe, H; Hellström, M; Kirchner, R; Rejmund, M; Roca, V; Roeckl, E; Romano, M; Rykaczewski, K; Schmidt, K; Terrasi, F

    2000-01-01

    The production of very neutron-deficient isotopes near sup 1 sup 0 sup 0 Sn has been investigated by using on-line mass separation of evaporation residues produced by heavy-ion induced complete-fusion reactions. We measured the cross sections for sup 9 sup 9 Cd, sup 1 sup 0 sup 0 In, sup 1 sup 0 sup 1 Sn and sup 1 sup 0 sup 2 In via sup 5 sup 8 Ni+ sup 5 sup 8 Ni fusion reactions followed by cluster emission, and via sup 5 sup 8 Ni+ sup 5 sup 0 Cr fusion reactions accompanied by evaporation of protons, neutrons or alpha particles. Both types of reactions yield similar cross sections for the production of exotic nuclei near sup 1 sup 0 sup 0 Sn. The data are discussed in comparison with results obtained from statistical-model calculations.

  9. Orbital-selective charge transfer at oxygen-deficient LaAlO3/SrTiO3(001) interfaces

    Science.gov (United States)

    Ong, P. V.; Lee, Jaichan

    2013-05-01

    Density-functional theory within the local density approximation + Hubbard U approach was used to study interface electronic structures in stoichiometric and oxygen-deficient LaAlO3/SrTiO3 (LAO/STO) superlattices with regularly spaced n-type and p-type interfaces. Asymmetric behaviors between complementary n-type and p-type interfaces were revealed in terms of orbital-selective charge transfer. Extra electrons induced by oxygen vacancies at the p-type interface easily spread to the n-type interface and occupy the Ti 3dxyorbitals, while those induced by the vacancies at the n-type interface are strictly confined and reside in Ti 3dx2-y2 and/or 3d3z2-r2 orbtials. The electronic behavior of oxygen vacancies at the LAO/STO interfaces and the possibility of distinguishing between intrinsic electronic states, which are induced by the polar catastrophe, and extrinsic states due to oxygen vacancies are discussed in detail.

  10. Magnetism, Spin Texture, and In-Gap States: Atomic Specialization at the Surface of Oxygen-Deficient SrTiO_{3}.

    Science.gov (United States)

    Altmeyer, Michaela; Jeschke, Harald O; Hijano-Cubelos, Oliver; Martins, Cyril; Lechermann, Frank; Koepernik, Klaus; Santander-Syro, Andrés F; Rozenberg, Marcelo J; Valentí, Roser; Gabay, Marc

    2016-04-15

    Motivated by recent spin- and angular-resolved photoemission (SARPES) measurements of the two-dimensional electronic states confined near the (001) surface of oxygen-deficient SrTiO_{3}, we explore their spin structure by means of ab initio density functional theory (DFT) calculations of slabs. Relativistic nonmagnetic DFT calculations display Rashba-like spin winding with a splitting of a few meV and when surface magnetism on the Ti ions is included, bands become spin-split with an energy difference ∼100  meV at the Γ point, consistent with SARPES findings. While magnetism tends to suppress the effects of the relativistic Rashba interaction, signatures of it are still clearly visible in terms of complex spin textures. Furthermore, we observe an atomic specialization phenomenon, namely, two types of electronic contributions: one is from Ti atoms neighboring the oxygen vacancies that acquire rather large magnetic moments and mostly create in-gap states; another comes from the partly polarized t_{2g} itinerant electrons of Ti atoms lying further away from the oxygen vacancy, which form the two-dimensional electron system and are responsible for the Rashba spin winding and the spin splitting at the Fermi surface.

  11. Effect of oxygen deficiency on the magnetic, electrical, magnetoelectric, and magnetoelastic properties of La1 - x Sr x MnO3 - δ manganites

    Science.gov (United States)

    Koroleva, L. I.; Zashchirinskiĭ, D. M.; Khapaeva, T. M.; Gurskiĭ, L. I.; Kalanda, N. A.; Trukhan, V. M.; Szymczak, R.; Krzumanska, B.

    2008-12-01

    This paper reports on a study of the effect of oxygen deficiency on the magnetic and electrical properties of the La1 - x Sr x MnO3 - δ manganites ( x = 0, 0.2, 0.4; δ = 0, 0.13, 0.2). In compositions with x = 0 and δ = 0.13 and 0.2, the temperature dependence of the magnetization M ( T) can be approximated by the Langevin function with the moment of superparamagnetic clusters μ = 77μB (δ = 0.13) and 86μB (δ = 0.2) at temperatures of 25 K ≤ T ≤ 250 K, with the exception of a small temperature range near 132 K in which a maximum characteristic of the LaMnO3 antiferromagnet is seen. These compositions, as well as Sr-doped compositions with δ ≠ 0, reveal a difference between the magnetizations of the sample cooled in a weak magnetic field and in zero field. At T = 6 K in a magnetic field of 16 kOe, the compositions with x = 0.2 and 0.4, δ = 0.13 possess a magnetic moment per formula unit lower than that with δ = 0, as well as reveal an anomalous relation between the Curie temperature T C and the Curie paramagnetic point gJ, namely, T C > gJ. The magnetization of compositions with x = 0.2 and 0.4, δ = 0.2 follows the Langevin function with μ = 40μB and 130μB, respectively. The electrical resistivity of samples with x = 0.4 and δ = 0.13 and 0.2 is one to two orders of magnitude larger than that of the composition with x = 0.4, δ = 0, which evidences partial or complete compensation of acceptor defects (Sr2+ ions) by donor defects (doubly charged O2- vacancies). The above properties of oxygen-deficient compositions suggest that they contain an insulating ferro-antiferromagnetic magnetically double-phase state. The magnetoresistance and volume magnetostriction in samples with x = 0.4 and δ = 0, 0.13, and 0.2 are small; indeed, in a magnetic field of 8 kOe, they do not exceed 1.4% and 6 × 10-6, respectively. On this basis, it is concluded that the unbalanced doubly charged donors (O vacancies) are in the state with antiparallel spins and, thus, do

  12. Mass measurement of cooled neutron-deficient bismuth projectile fragments with time-resolved Schottky mass spectrometry at the FRS-ESR facility

    Energy Technology Data Exchange (ETDEWEB)

    Litvinov, Yu.A.; Geissel, H. [Giessen Univ. (Germany); Radon, T. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (DE)] [and others

    2005-06-01

    Masses of 582 neutron-deficient nuclides (30{<=}Z{<=}85) were measured with time-resolved Schottky mass spectrometry at the FRS-ESR facility at GSI, 117 were used for calibration. The masses of 71 nuclides were obtained for the first time. A typical mass accuracy of 30 {mu}u was achieved. These data have entered the latest atomic mass evaluation. The mass determination of about 140 additional nuclides was possible via known energies (Q-values) of {alpha}-, {beta}-, or proton decays. The obtained results are compared with the results of other measurements. (orig.)

  13. A-Site Deficient (Pr0.6Sr0.4)(1-s)Fe0.8Co0.2O3-delta Perovskites as Solid Oxide Fuel Cell Cathodes

    DEFF Research Database (Denmark)

    Kammer Hansen, Kent

    2009-01-01

    Five A-site deficient (Pr0.6Sr0.4)1−sFe0.8Co0.2O3− perovskites (s=0.01, 0.05, 0.10, 0.15, and 0.20) were synthesized using the glycine-nitrate process. The perovskites were characterized with powder X-ray diffraction (XRD), dilatometry, four-point dc conductivity measurements, and electrochemical...... resistance more than 3 times lower than the weakly A-site deficient (Pr0.6Sr0.4)0.99Fe0.8Co0.2O3− perovskite. ©2009 The Electrochemical Society...

  14. A-Site Deficient (Pr0.6Sr0.4)(1-s)Fe0.8Co0.2O3-delta Perovskites as Solid Oxide Fuel Cell Cathodes

    DEFF Research Database (Denmark)

    Kammer Hansen, Kent

    2009-01-01

    Five A-site deficient (Pr0.6Sr0.4)1−sFe0.8Co0.2O3− perovskites (s=0.01, 0.05, 0.10, 0.15, and 0.20) were synthesized using the glycine-nitrate process. The perovskites were characterized with powder X-ray diffraction (XRD), dilatometry, four-point dc conductivity measurements, and electrochemical...

  15. Influence of Cr deficiency on sintering, thermal expansion and electrical properties of La0.75Sr0.25Cr1-xO3-δ as a SOFC interconnect material

    Science.gov (United States)

    Ren, Yi; Ma, Wen; Li, Xiaoying; Wang, Jun; Bai, Yu; Dong, Hongying

    2016-04-01

    The SOFC interconnect materials La0.75Sr0.25Cr1-xO3-δ (x = 0-0.04) were prepared using an auto-ignition process. The influences of Cr deficiency on their sintering, thermal expansion and electrical properties were investigated. All the samples were pure perovskite phase after sintering at 1400∘C for 4 h. The cell volume of La0.75Sr0.25Cr1-xO3-δ decreased with increasing Cr deficient content. The relative density of the sintered bulk samples increased from 93.2% (x = 0) to a maximum value of 94.7% (x = 0.02) and then decreased to 87.7% (x = 0.04). The thermal expansion coefficients of the sintered bulk samples were in the range of 10.60-10.98 × 10-6K-1 (30-1000∘C), which are compatible with that of YSZ. Among the investigated samples, the sample with 0.02 Cr deficiency had a maximum conductivity of 40.4 Scm-1 and the lowest Seebeck coefficient of 154.8 μVK-1 at 850∘C in pure He. The experimental results indicate that La0.75Sr0.25Cr0.98O3-δ has the best properties and is much suitable for SOFC interconnect material application.

  16. Reactivity, structure and physical properties of SrCo{sub 2.5+{delta}} and La{sub 2}CoO{sub 4.0+{delta}}. In situ X-ray diffraction and neutrons study; Reactivite, structure et proprietes physiques de SrCoO{sub 2.5+{delta}} et La{sub 2}CoO{sub 4.0+{delta}}. Etude par diffraction des rayons X et des neutrons in situ

    Energy Technology Data Exchange (ETDEWEB)

    Le Toquin, R.

    2003-11-15

    This work was devoted to the study of the reactivity and more specifically the influence of the intercalated oxygen amount {delta} on the structure and physical properties of SrCoO{sub 2.5+{delta}} et La{sub 2}CoO{sub 4.0+{delta}} We controlled the oxidation level by means of reversible electrochemical red ox reaction at room temperature. Structural modifications, especially disorder, and electronic properties were studied for the first time on large orientated single crystal. In the SrCoO{sub 2.5+{delta}} system, after structural and electronic characterisation of the end phases, we studied the real structure of the brownmillerite SrCoO{sub 2.5} phase using single crystal. Moreover, we investigated structural and magnetic evolution upon red ox cycle using X-ray diffraction on 6 times twinned single crystal and in situ neutron powder diffraction. Two intermediate SrCoO{sub 2.75} and SrCoO{sub 2.82} phases have been observed. The reaction on single crystal has evidenced the evolution of domain structure. For the La{sub 2}CoO{sub 4+{delta}} system, we synthesised a large variety of single crystal with stoichiometry {delta} 0.0, 0.09, 0.12, 0.16, 0.20 and 0.25. Using single crystal X-ray and neutron diffraction, we showed a disorder-order transition of the apical and interstitial oxygen for the higher {delta} values. (author)

  17. Shape coexistence measurements in even-even neutron-deficient polonium isotopes by Coulomb excitation, using REX-ISOLDE and the Ge MINIBALL array

    CERN Multimedia

    Butler, P; Bastin, B; Kruecken, R; Voulot, D; Rahkila, P J; Orr, N A; Srebrny, J; Grahn, T; Clement, E; Paul, E S; Gernhaeuser, R A; Dorsival, A; Diriken, J V J; Huyse, M L; Iwanicki, J S

    The neutron-deficient polonium isotopes with two protons outside the closed Z=82 shell represent a set of nuclei with a rich spectrum of nucleus structure phenomena. While the onset of the deformation in the light Po isotopes is well established experimentally, questions remain concerning the sign of deformation and the magnitude of the mixing between different configurations. Furthermore, controversy is present with respect to the transition from the vibrational-like character of the heavier Po isotopes to the shape coexistence mode observed in the lighter Po isotopes. We propose to study this transition in the even-mass neutron-deficient $^{198,200,202}$Po isotopes by using post-accelerated beams from REX-ISOLDE and "safe"-energy Coulomb excitation. $\\gamma$- rays will be detected by the MINIBALL array. The measurements of the Coulomb excitation differential cross section will allow us to deduce both the transition and diagonal matrix elements for these nuclei and, combined with lifetime measurements, the s...

  18. Study of magnetic excitations in the high critical temperature La{sub 2-x}Sr{sub x}CuO{sub 4} superconductor with neutrons inelastic scattering; Etude des excitations magnetiques dans le supraconducteur a haute temperature critique La{sub 2-x}Sr{sub x}CuO{sub 4} par diffusion inelastique des neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Petit, S

    1997-11-25

    In this work, we question the relevance of spin correlations in the problem of high-T{sub c} superconductivity. To characterize these correlations, we present a detailed inelastic neutron scattering study of the magnetic excitations spectrum, in the high T{sub c} La{sub 2-x}Sr{sub x}CuO{sub 4} copper oxide superconductor, as a function of temperature and strontium content x. Our study demonstrates the existence of two distinct types of fluctuations. The first type corresponds to two-dimensional isotropic fluctuations peaked at incommensurate points around the antiferromagnetic wavevector. These fluctuations show a gap below T{sub c}. The second type of fluctuations corresponds to two-dimensional very low energy, typically 1 MeV, antiferromagnetic correlations. They arise at low temperatures, for T {<=}T{sub f} {approx} 10 K {<=}T{sub c}. Different scenarios are discussed, namely particle-hole excitation arising because of nesting properties of the Fermi surface, stripes, and localized carriers in the CuO{sub 2} plane because of the La/Sr substitution disorder. Next, aiming to study the interrelation between magnetism and superconductivity, we present a theoretical perturbative treatment of the t-t`-J model. This model is believed to describe the physics of the CuO{sub 2} plane. The considered quasiparticles describe the motion of a doped hole, followed by localized spins on the copper sites. For a given doping x, two phases can exist, containing either x or 1 + x of these quasiparticles. We show at in the second phase, the exchange interaction between localized spins, combined to the intrinsic anharmonicity of these quasiparticles leads to an attractive interaction between them. We study the stability and the symmetry of a superconducting phase based on this mechanism. (author) 215 refs.

  19. Size-induced ferromagnetism and metallicity in Nd{sub 0.5}Sr{sub 0.5}MnO{sub 3} nanoparticles: A neutron diffraction study

    Energy Technology Data Exchange (ETDEWEB)

    Kundu, S., E-mail: souravphy@gmail.com [Department of Physics and Meteorology, Indian Institute of Technology, Kharagpur 721302 (India); Das, A. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Nath, T.K., E-mail: tnath@phy.iitkgp.ernet.in [Department of Physics and Meteorology, Indian Institute of Technology, Kharagpur 721302 (India); Nigam, A.K. [Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 (India)

    2012-03-15

    The phenomenon of destabilization of antiferromagnetic insulating state into a ferromagnetic metallic one in Nd{sub 0.5}Sr{sub 0.5}MnO{sub 3} with the variation of particle/grain size is critically investigated. Based on our neutron diffraction study, magnetic and transport experiments, we observe ferromagnetism and metallic behavior in Nd{sub 0.5}Sr{sub 0.5}MnO{sub 3} ({approx}40 nm grain size) as against A-type antiferromagnetic order in the sample with the largest grain size ({approx}800 nm). The latter shows a systematic change in the lattice parameters with temperature, and an antiferromagnetic ground state similar to that of a bulk system. Interestingly, the sample with the smallest grain sizes exhibits insignificant structural changes (compared to the largest grain size sample) but a complete change in the magnetic state (ferromagnetic behavior) as revealed from the neutron diffraction study. Magnetic measurements also confirm a ferromagnetic state in the small-grained sample. Electronic transport measurements exhibit a metal-insulator transition in this sample. The effects are primarily attributed to enhanced surface disorder. - Highlights: Black-Right-Pointing-Pointer Ferromagnetic metallic state (FMM) is found in nano-sized Nd{sub 0.5}Sr{sub 0.5}MnO{sub 3} ({approx}40 nm). Black-Right-Pointing-Pointer FMM is confirmed from detailed neutron diffraction, magnetic and transport studies. Black-Right-Pointing-Pointer Surface pressure is found to be insufficient to explain the effects. Black-Right-Pointing-Pointer Role of enhanced surface disorder and strain modification have been discussed.

  20. Shape coexistence in neutron-deficient Hg isotopes studied via lifetime measurements in $^{184,186}$Hg and two-state mixing calculations

    CERN Document Server

    Gaffney, L P; Page, R.D.; Grahn, T.; Scheck, M.; Butler, P.A.; Bertone, P.F.; Bree, N.; Carroll, R.J.; Carpenter, M.P.; Chiara, C.J.; Dewald, A.; Filmer, F.; Fransen, C.; Huyse, M.; Janssens, R.V.F.; Joss, D.T.; Julin, R.; Kondev, F.G.; Nieminen, P.; Pakarinen, J.; Rigby, S.V.; Rother, W.; Van Duppen, P.; Watkins, H.V.; Wrzosek-Lipska, K.; Zhu, S.

    2014-01-01

    The neutron-deficient mercury isotopes, $^{184,186}$Hg, were studied with the Recoil Distance Doppler Shift (RDDS) method using the Gammasphere array and the K\\"oln Plunger device. The Differential Decay Curve Method (DDCM) was employed to determine the lifetimes of the yrast states in $^{184,186}$Hg. An improvement on previously measured values of yrast states up to $8^{+}$ is presented as well as first values for the $9_{3}$ state in $^{184}$Hg and $10^{+}$ state in $^{186}$Hg. $B(E2)$ values are calculated and compared to a two-state mixing model which utilizes the variable moment of inertia (VMI) model, allowing for extraction of spin-dependent mixing strengths and amplitudes.

  1. Neutron Scattering Study on La1.9Ca1.1Cu2O6+delta and La1.85Sr0.15Ca Cu2O6+delta

    Energy Technology Data Exchange (ETDEWEB)

    Hucker,M.; Kim, Y.; Gu, G.; Tranquada, J.; Gaulin, B.; Lynn, J.

    2005-01-01

    We present neutron scattering data on two single crystals of the high temperature superconductor La{sub 2-x}(Ca, Sr){sub x}CaCu{sub 2}O{sub 6+{delta}}. The Ca{sub 0.1}-doped crystal exhibits a long-range antiferromagnetically ordered ground state. In contrast, the Sr{sub 0.15}-doped crystal exhibits short-range antiferromagnetic order as well as weak superconductivity. In both crystals antiferromagnetic correlations are commensurate; however, some results on the Ca{sub 0.1}-doped crystal resemble those on the spin-glass phase of La{sub 2-x}Sr{sub x}CuO{sub 4}, where magnetic correlations became incommensurate. In addition, both crystals show a structural transition from tetragonal to orthorhombic symmetry. Quite remarkably, the temperature dependence and correlation length of the magnetic order is very similar to that of the orthorhombic distortion. We attribute this behavior to an orthorhombic strain-induced interbilayer magnetic coupling, which triggers the antiferromagnetic order. The large size of the crystals made it also possible to study the magnetic diffuse scattering along rods perpendicular to the CuO{sub 2} planes in more detail. For comparison we show x-ray diffraction and magnetization data. In particular, for the Ca{sub 0.1}-doped crystal these measurements reveal valuable information on the spin-glass transition as well as a second anomaly associated with the N{acute e}el transition.

  2. Restoration of high-density lipoprotein levels by cholesteryl ester transfer protein expression in scavenger receptor class B type I (SR-BI) knockout mice does not normalize pathologies associated with SR-BI deficiency

    NARCIS (Netherlands)

    Hildebrand, Reeni B; Lammers, Bart; Meurs, Illiana; Korporaal, Suzanne J A; De Haan, Willeke; Zhao, Ying; Kruijt, J Kar; Praticò, Domenico; Schimmel, Alinda W M; Holleboom, Adriaan G; Hoekstra, Menno; Kuivenhoven, Jan Albert; Van Berkel, Theo J C; Rensen, Patrick C N; Van Eck, Miranda

    OBJECTIVE: Disruption of scavenger receptor class B type I (SR-BI) in mice impairs high-density lipoprotein (HDL)-cholesterol (HDL-C) delivery to the liver and induces susceptibility to atherosclerosis. In this study, it was investigated whether introduction of cholesteryl ester transfer protein

  3. A variable field neutron study of the negative magnetoresistive ruthenocuprate RuSr 2Nd 0.9Y 0.2Ce 0.9Cu 2O 10-δ

    Science.gov (United States)

    Mclaughlin, A. C.; Attfield, J. P.

    2007-03-01

    A variable field neutron diffraction study of the ruthenocuprate RuSr 2Nd 0.9Y 0.2Ce 0.9Cu 2O 10-δ, which exhibits large negative magnetoresistance, has been performed in order to determine the variation of the magnetic structure with magnetic field. Upon application of a magnetic field the ({1}/{2} {1}/{2} {1}/{2}) and ({1}/{2} {1}/{2} l) magnetic peaks reduce in intensity as the spins in the RuO 2 and CuO 2 layer cant into a ferromagnetic alignment in the ab-plane. This results in increased spin polarised transport in the CuO 2 plane and hence large negative magnetoresistance.

  4. Reply to “Structural and magnetic behavior of the cubic oxyfluoride SrFeO{sub 2}F studied by neutron diffraction”

    Energy Technology Data Exchange (ETDEWEB)

    Clemens, Oliver, E-mail: oliver.clemens@kit.edu [Technische Universität Darmstadt, Joint Research Laboratory Nanomaterials, Jovanka-Bontschits-Straße 2, 64287 Darmstadt (Germany); Karlsruher Institut für Technologie, Institut für Nanotechnologie, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Berry, Frank J.; Wright, Adrian J. [School of Chemistry, The University of Birmingham, Birmingham B15 2TT (United Kingdom); Knight, Kevin S. [ISIS Facility, Rutherford Appleton Laboratory, Harwell Oxford, Didcot OX11 0QX (United Kingdom); Perez-Mato, J.M.; Igartua, J.M. [Departamentos de Física de la Materia Condensada y Física Aplicada II, Facultad de Ciencia y Tecnología, Universidad del País Vasco (UPV/EHU), Apdo. 644, 48080 Bilbao (Spain); Slater, Peter R. [School of Chemistry, The University of Birmingham, Birmingham B15 2TT (United Kingdom)

    2015-03-15

    In this article we comment on the results published by Thompson et al. (, J. Solid State Chem. 219 (2014) 173–178) on the crystal structure of SrFeO{sub 2}F, who claim the compound to crystallize in the cubic space group Pm-3m. We give a more detailed explanation of the determination of our previously reported structural model with Imma symmetry (Clemens et al., J. Solid State Chem. 206 (2013) 158–169), with addition of variable temperature XRD measurements with high counting time to provide unambiguous evidence for the Imma model being correct for our sample. - Graphical abstract: The crystal structure of SrFeO{sub 2}F is discussed with regards to previous reports. - Highlights: • SrFeO{sub 2}F was synthesized by polymer based fluorination of SrFeO{sub 3}. • Evaluation of the diffraction data shows a pseudocubic cell metric. • Superstructure reflections at low d-spacings indicate deviation from cubic symmetry. • The phase transition temperature from orthorhombic to cubic was determined using variable temperature X-ray diffraction. • Results published by Thompson et al. are critically discussed with respect to those observations.

  5. Alpha Decay as a Prob e of the Structure of Neutron-deficient Nuclei Around Z=82

    Institute of Scientific and Technical Information of China (English)

    亓冲

    2016-01-01

    In this contribution I would like to review briefly our recent studies on nuclear α formation probabilities in heavy nuclei and their indication on the underlying structure of the nuclei involved. In particular, I will show that the empirical α-formation probabilities, which can be extracted from experimental half-lives, exhibit a rather smooth function with changing proton or neutron numbers. This allows us to distinguish the role played by pairing collectivity in the clustering process. The sudden hindrance of the clustering of the nucleons around the N=126 shell closure is due to the fact that the configuration space does not allow a proper manifestation of the pairing collectivity. The influence of the Z=82 shell closure on the α formation properties will also be discussed. Moreover, we have evaluated the α-decay fine structure to excited 0+ states in Hg and Rn isotopes as well as the α-decay from the excited 0+ states in the mother nucleus. It is thus found that the α decay is sensitive to the mixture of configurations corresponding to different nuclear shapes.

  6. Tentative study of nuclear charge radii for neutron-deficient nuclei around the Z = 82 shell from experimental α decay data

    Energy Technology Data Exchange (ETDEWEB)

    Qian, Yibin, E-mail: qyibin@njust.edu.cn [Department of Applied Physics, Nanjing University of Science and Technology, Nanjing 210094 (China); Department of Physics and Key Laboratory of Modern Acoustics, Nanjing University, Nanjing 210093 (China); Ren, Zhongzhou [Department of Physics and Key Laboratory of Modern Acoustics, Nanjing University, Nanjing 210093 (China); Center of Theoretical Nuclear Physics, National Laboratory of Heavy-Ion Accelerator, Lanzhou 730000 (China); Kavli Institute for Theoretical Physics China, Beijing 100190 (China)

    2016-01-15

    We tentatively investigate the root-mean-square (rms) nuclear charge radii of odd-A Po and Pb isotopes plus Tl isotopes, particularly concerning these difficultly-detected nuclei along with short lifetimes, via various data on α decay. Within the density-dependent cluster model, the density distributions of studied daughter nuclei are determined by exactly reproducing the corresponding experimental α decay half-lives, which leads the final results of nuclear charge radii. In addition, our recently proposed formula deducing the charge radii is extended to this study for comparison. Whether it concerns the ground or isomeric state of target nuclei, the extracted nuclear charge radii are found to be in good agreement with the measured values. Sequential predictions on the rms charge radii are subsequently made for these neutron-deficient nuclei and especially for the rarely detected Bi isotopic chain, which are expected to be useful for future measurements. Moreover, the variety of α-preformation factors is analyzed in the scheme of valence nucleon number to pursue the further improvement of the model. This may be considered as an effective effort to obtain the charge radii of ground and even low-lying excited states for exotic nuclei near the proton-dripline.

  7. Magnetism, spin texture and in-gap states. Atomic specialization at the surface of oxygen-deficient SrTiO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Jeschke, Harald O.; Altmeyer, Michaela; Valenti, Roser [Institut fuer Theoretische Physik, Goethe-Universitaet Frankfurt, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main (Germany); Rozenberg, Marcelo; Gabay, Marc [Laboratoire de Physique des Solides, Bat 510, Universite Paris-Sud, 91405 Orsay (France)

    2016-07-01

    We investigate the electronic structure and spin texture at the (001) surface of SrTiO{sub 3} in the presence of oxygen vacancies by means of ab initio density functional theory (DFT) calculations of slabs. Relativistic non-magnetic DFT calculations exhibit Rashba-like spin winding with a characteristic energy scale ∝ 10 meV. However, when surface magnetism on the Ti ions is included, bands become spin-split with an energy difference ∝ 100 meV at the Γ point. This energy scale is comparable to the observations in SARPES experiments performed on the two-dimensional electronic states confined near the (001) surface of SrTiO{sub 3}. We find the spin polarized state to be the ground state of the system, and while magnetism tends to suppress the effects of the relativistic Rashba interaction, signatures of it are still clearly visible in terms of complex spin textures.

  8. Study of neutron-deficient isotopes of Fl in the 239Pu, 240Pu + 48Ca reactions

    Science.gov (United States)

    Voinov, A. A.; Utyonkov, V. K.; Brewer, N. T.; Oganessian, Yu Ts; Rykaczewski, K. P.; Abdullin, F. Sh; Dmitriev, S. N.; Grzywacz, R. K.; Itkis, M. G.; Miernik, K.; Polyakov, A. N.; Roberto, J. B.; Sagaidak, R. N.; Shirokovsky, I. V.; Shumeiko, M. V.; Tsyganov, Yu S.; Subbotin, V. G.; Sukhov, A. M.; Sabelnikov, A. V.; Vostokin, G. K.; Hamilton, J. H.; Stoyer, M. A.; Strauss, S. Y.

    2016-07-01

    The results of the experiments aimed at the synthesis of Fl isotopes in the 239Pu + 48Ca and 240Pu + 48Ca reactions are presented. The experiment was performed using the Dubna gas-filled recoil separator at the U400 cyclotron. In the 239Pu+48Ca experiment one decay of spontaneously fissioning 284Fl was detected at 245-MeV beam energy. In the 240Pu+48Ca experiment three decay chains of 285Fl were detected at 245 MeV and four decays were assigned to 284Fl at the higher 48Ca beam energy of 250 MeV. The α-decay energy of 285Fl was measured for the first time and decay properties of its descendants 281Cn, 277Ds, 273Hs, 269Sg, and 265Rf were determined more precisely. The cross section of the 239Pu(48Ca,3n)284Fl reaction was observed to be about 20 times lower than those predicted by theoretical models and 50 times less than the value measured in the 244Pu+48Ca reaction. The cross sections of the 240Pu(48Ca,4-3n)284,285Fl at both 48Ca energies are similar and exceed that observed in the reaction with lighter isotope 239Pu by a factor of 10. The decay properties of the synthesized nuclei and their production cross sections indicate rapid decrease of stability of superheavy nuclei with departing from the neutron number N=184 predicted to be the next magic number.

  9. Magnetoresistance Versus Oxygen Deficiency in Epi-stabilized SrRu1 - x Fe x O3 - δ Thin Films.

    Science.gov (United States)

    Dash, Umasankar; Acharya, Susant Kumar; Lee, Bo Wha; Jung, Chang Uk

    2017-12-01

    Oxygen vacancies have a profound effect on the magnetic, electronic, and transport properties of transition metal oxide materials. Here, we studied the influence of oxygen vacancies on the magnetoresistance (MR) properties of SrRu1 - x Fe x O3 - δ epitaxial thin films (x = 0.10, 0.20, and 0.30). For this purpose, we synthesized highly strained epitaxial SrRu1 - x Fe x O3 - δ thin films with atomically flat surfaces containing different amounts of oxygen vacancies using pulsed laser deposition. Without an applied magnetic field, the films with x = 0.10 and 0.20 showed a metal-insulator transition, while the x = 0.30 thin film showed insulating behavior over the entire temperature range of 2-300 K. Both Fe doping and the concentration of oxygen vacancies had large effects on the negative MR contributions. For the low Fe doping case of x = 0.10, in which both films exhibited metallic behavior, MR was more prominent in the film with fewer oxygen vacancies or equivalently a more metallic film. For semiconducting films, higher MR was observed for more semiconducting films having more oxygen vacancies. A relatively large negative MR (~36.4%) was observed for the x = 0.30 thin film with a high concentration of oxygen vacancies (δ = 0.12). The obtained results were compared with MR studies for a polycrystal of (Sr1 - x La x )(Ru1 - x Fe x )O3. These results highlight the crucial role of oxygen stoichiometry in determining the magneto-transport properties in SrRu1 - x Fe x O3 - δ thin films.

  10. Weak interaction rates for Kr and Sr waiting-point nuclei under rp-process conditions

    Energy Technology Data Exchange (ETDEWEB)

    Sarriguren, P., E-mail: sarriguren@iem.cfmac.csic.e [Instituto de Estructura de la Materia, CSIC, Serrano 123, E-28006 Madrid (Spain)

    2009-10-12

    Weak interaction rates are studied in neutron deficient Kr and Sr waiting-point isotopes in ranges of densities and temperatures relevant for the rp process. The nuclear structure is described within a microscopic model (deformed QRPA) that reproduces not only the half-lives but also the Gamow-Teller strength distributions recently measured. The various sensitivities of the decay rates to both density and temperature are discussed. Continuum electron capture is shown to contribute significantly to the weak rates at rp-process conditions.

  11. POLI-HEiDi: The new polarised neutron diffractometer at the hot source (SR9) at the FRM II-Project status

    Energy Technology Data Exchange (ETDEWEB)

    Hutanu, V., E-mail: vladimir.hutanu@frm2.tum.d [Institut fuer Kristallographie RWTH Aachen University, Jaegerstr 17-19, D-52056 Aachen (Germany); Neutronenforschungsquelle Heinz Maier-Leibnitz FRM II TU Munich, Lichtenberg str. 1, 85747 Garching (Germany); Meven, M. [Neutronenforschungsquelle Heinz Maier-Leibnitz FRM II TU Munich, Lichtenberg str. 1, 85747 Garching (Germany); Lelievre-Berna, E. [Institut Laue-Langevin (ILL), 6 rue Jules Horowitz 38042 Grenoble, Cedex 9 (France); Heger, G. [Institut fuer Kristallographie RWTH Aachen University, Jaegerstr 17-19, D-52056 Aachen (Germany)

    2009-09-01

    The project to upgrade the existing single-crystal diffractometer Heisses Einkristal Diffractometer (HEiDi) at FRM II with a polarised neutron option, enabling the investigation of magnetic ground states in single crystals has been ongoing since autumn 2004. After a detailed investigation of the possible options it has been decided to develop and rebuild the secondary spectrometer and keep the HEiDi monocromator. The new instrument has been named POLI-HEiDi as an abbreviation of Polarisation Investigator at HEiDi. Two different zero-field polarimeters will be made available for spherical neutron polarimetry, Cryoapad and MuPAD. Both, polarisation and analysis will be performed with polarised {sup 3}He spin filters. Several new and important components of the instrument have recently been commissioned. In this report we present these components and show how they fit with the design of the whole instrument.

  12. Low-energy dispersion of dynamic charge stripes in La1.75Sr0.25NiO4 observed with inelastic neutron scattering

    Science.gov (United States)

    Zhong, Ruidan; Tranquada, John; Gu, Genda; Reznik, Dmitry; Winn, Barry

    The dynamic stripe correlations have been the subject of intense research, owing to the possible links with high-Tc superconductivity. In light of a recently published, direct observation of charge-stripe fluctuations in La2-xSrxNiO4 using inelastic neutron scattering, we did a follow-up neutron experiment on a x=0.25 sample to characterize the low-energy dispersion of these dynamic charge stripes using the HYSPEC instrument at the Spallation Neutron Source. The scattering signals are collected in the vicinity of a charge-order peak with a large wave vector (4.4, 3, 0), where dynamic spin-stripe correlations are negligible. Mapping the low-energy charge-stripe fluctuations in a wide temperature range, we observe a finite dispersion along the stripe-modulation direction at T >=160K where the charge stripes become disordered, while the steep dispersion in the orthogonal direction is not resolved. Work at BNL supported by Office of Basic Energy Sciences, US DOE, under Contract No. DE-SC00112704.

  13. Transformation of Structure, Electrical Conductivity, and Magnetism in AA'Fe2O6-δ, A = Sr, Ca and A' = Sr.

    Science.gov (United States)

    Hona, Ram Krishna; Huq, Ashfia; Mulmi, Suresh; Ramezanipour, Farshid

    2017-08-21

    The ability to control electrical properties and magnetism by varying the crystal structure using the effect of the A-site cation in oxygen-deficient perovskites has been studied in AA'Fe2O6-δ, where A = Sr, Ca and A' = Sr. The structure of Sr2Fe2O6-δ, synthesized at 1250 °C in air, contains dimeric units of FeO5 square pyramids separated by FeO6 octahedra. Here we show that this ordering scheme can be transformed by changing the A-site cations from Sr to Ca. This leads to a structure where layers of corner-sharing FeO6 octahedra are separated by chains of FeO4 tetrahedra. Through systematic variation of the A-site cations, we have determined the average ionic radius required for this conversion to be ∼1.41 Å. We have demonstrated that the magnetic structure is also transformed. The Sr2 compound has an incommensurate magnetic structure, where magnetic moments are in spin-density wave state, aligning perpendicular to the body diagonal of the unit cell. With the aid of neutron diffraction experiments at 10 and 300 K, we have shown that the magnetic structure is converted into a long-range G-type antiferromagnetic system when one Sr is replaced by Ca. In this G-type ordering scheme, the magnetic moments align in the 001 direction, antiparallel to their nearest neighbors. We have also performed variable-temperature electrical conductivity studies on these materials in the temperature range 298-1073 K. These studies have revealed the transformation of charge transport properties, where the metallic behavior of the Sr2 compound is converted into semiconductivity in the CaSr material. The trend of conductivity as a function of temperature is reversed upon changing the A-site cation. The conductivity of the Sr2 compound shows a downturn, while the conductivity of the CaSr material increases as a function of temperature. We have also shown that the CaSr compound exhibits temperature-dependent behavior typical of a mixed ionic-electronic conducting system.

  14. Progress report on neutron beam experiments in Thailand: effects of antimony substitutions on the critical temperature of Bi-Pb-Sr-Ca-Cu-O compounds

    Energy Technology Data Exchange (ETDEWEB)

    Sangariyavanich, A.; Ampornrat, P. [Office of Atomic Energy for Peace, Bangkok (Thailand)

    1998-10-01

    Effects of systematic substitutions of antimony for bismuth in Bi{sub 1.8-x}Pb{sub 0.2}Sb{sub x}Sr{sub 2}Ca{sub 3}Cu{sub 4}O{sub 10} have been investigated. Fabrication of the specimens has been performed by solid state reaction in air. The samples were sintered between 820degC - 843degC for 65 hours and subsequently quenched in liquid nitrogen. The critical temperatures of most specimens as determined by standard four-probe technique was higher than 100 K. Phase identification by X-ray diffraction technique indicated that `2223` and `2234` were the predominant phases in these samples. (author)

  15. Neutron-scattering study of stripe-phase order of holes and spins in La1.48Nd0.4Sr0.12CuO4

    Science.gov (United States)

    Tranquada, J. M.; Axe, J. D.; Ichikawa, N.; Nakamura, Y.; Uchida, S.; Nachumi, B.

    1996-09-01

    We present a neutron diffraction study of charge and spin order within the CuO2 planes of La1.48Nd0.4Sr0.12CuO4, a crystal in which superconductivity is anomalously suppressed. At low temperatures we observe elastic magnetic superlattice peaks of the type (1/2+/-ɛ,1/2,0) and charge-order peaks at (2+/-2ɛ,0,0), where ɛ=0.118. After cooling the crystal through the low-temperature-orthorhombic (LTO) to low-temperature-tetragonal (LTT) phase transition near 70 K, the charge-order peaks appear first at ~60 K, with the magnetic peaks appearing below 50 K. The magnetic peaks increase in intensity by an order of magnitude below 3 K due to ordering of the Nd ions. We show that the observed diffraction features are consistent with stripe-phase order, in which the dopant-induced holes collect in domain walls that separate antiferromagnetic antiphase domains. The Q dependence of the magnetic scattering indicates that the low-temperature correlation length within the planes is substantial (~170 Å), but only very weak correlations exist between next-nearest-neighbor planes. Correlations between nearest-neighbor layers are frustrated by pinning of the charge stripes to the lattice distortions of the LTT phase. The spin-density-wave amplitude corresponds to a Cu moment of 0.10+/-0.03 μB. The behavior of the electrical resistivity within the LTT phase is examined, and the significance of stripe-phase correlations for understanding the unusual transport properties of layered cuprates is discussed.

  16. A neutron diffraction study and mode analysis of compounds of the system La{sub 1−x}Sr{sub x}FeO{sub 3−x}F{sub x} (x=1, 0.8, 0.5, 0.2) and an investigation of their magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Clemens, Oliver, E-mail: oliver.clemens@kit.edu [School of Chemistry, The University of Birmingham, Birmingham B15 2TT (United Kingdom); Berry, Frank J.; Wright, Adrian J. [School of Chemistry, The University of Birmingham, Birmingham B15 2TT (United Kingdom); Knight, Kevin S. [ISIS Facility, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, OX11 0QX (United Kingdom); Perez-Mato, J.M.; Igartua, J.M. [Departamentos de Física de la Materia Condensada y Física Aplicada II, Facultad de Ciencia y Tecnología, Universidad del País Vasco (UPV/EHU), Apdo. 644, 48080 Bilbao (Spain); Slater, Peter R. [School of Chemistry, The University of Birmingham, Birmingham B15 2TT (United Kingdom)

    2013-10-15

    We report here a detailed study of the system La{sub 1−x}Sr{sub x}FeO{sub 3−x}F{sub x}, by neutron powder diffraction- and magnetic-measurements. All the compounds are robust antiferromagnetics with ordering temperatures well above room temperature. Magnetic moments are shown to align parallel to the c-axis. FC-ZFC measurements indicate a small canting of the magnetic moments, resulting in a ferromagnetic component with a maximum for La{sub 0.5}Sr{sub 0.5}FeO{sub 2.5}F{sub 0.5}. We show that the system exhibits a composition-driven transition from a phase, for low fluorination levels (x≤0.5), with Pnma symmetry and the usual system of octahedral tiltings, to a phase with space group Imma for higher fluorine contents, where a correlated distortion of the oxygen octahedra plays a significant role. The consistency of the structural models, with respect to the expected continuity of the amplitudes of the different distortion modes and the invariance of their internal form, was monitored through the symmetry mode decomposition of the structures. - Graphical abstract: The crystal and magnetic structure of La{sub 0.5}Sr{sub 0.5}FeO{sub 2.5}F{sub 0.5}. Display Omitted - Highlights: • The compounds La{sub 1−x}Sr{sub x}FeO{sub 3−x}F{sub x} (x=1, 0.8, 0.5, 0.2) were studied by neutron diffraction. • A mode analysis shows lower symmetry for Sr rich compounds than previously reported. • SrFeO{sub 2}F crystallizes in the orthorhombic space group Imma. • Magnetic moments resulting from canting depend on metric distortion. • The magnetic structure was determined for La{sub 0.5}Sr{sub 0.5}FeO{sub 2.5}F{sub 0.5}.

  17. ANTARES: Cold neutron radiography and tomography facility

    OpenAIRE

    Schulz, Michael; Schillinger, Burkhard

    2015-01-01

    The neutron imaging facility ANTARES, operated by the Technische Universität München, is located at the cold neutron beam port SR-4a. Based on a pinhole camera principle with a variable collimator located close to the beam port, the facility provides the possibility for flexible use in high resolution and high flux imaging.

  18. Study by neutrons diffusion and X-rays of structural and magnetic properties of Bi{sub 2}Sr{sub 2}Ca{sub n-1}Cu{sub n}O{sub 2n+4+{delta}} type superconductive cuprates; Etude par diffusion des neutrons et des rayons X des proprietes structurales et magnetiques des cuprates supraconducteurs de type Bi{sub 2}Sr{sub 2}Ca{sub n-1}Cu{sub n}O{sub 2n+4+{delta}}

    Energy Technology Data Exchange (ETDEWEB)

    Vasiliu-Doloc, L.

    1995-09-22

    In this work we have used inelastic and elastic neutron and X-ray scattering techniques for characterizing the incommensurate structural distortions in compounds belonging to the family Bi{sub 2}Sr{sub 2}Ca{sub n-1}Cu{sub n}O{sub 2n+4+{delta}} of high-Tc superconducting cuprates. We have searched the existence of structural instabilities specific of the CuO{sub 2} planes and of magnetic instabilities. The modulated structure of the 2212 phase has been refined from single-crystal neutron diffraction results and importance of distortion of CuO{sub 2} planes has thus been determined. It is shown that the additional oxygen is not ordered three-dimensionally within the modulated structure and that the information about it is contained in diffuse scattering results. A model of the short-range order associated with additional oxygen atoms is proposed and discussed. The temperature studies of the long-range order have shown a great stability of the amplitude and period of the incommensurate distortion wave in the one-layer, as well as in the double-layer compounds, either superconducting or insulating. We find such a behaviour to be highly incompatible with a distortion resulting from a charge-density-wave instability. The results we have obtained indicate that the bismuth-based high-Tc superconducting cuprates have essentially the same physics of the CuO{sub 2} planes as the previous two families, La{sub 2-x}Sr{sub x}CuO{sub 4} and YBa{sub 2}Cu{sub 3}O{sub 6+{delta}}, being at the proximity of three instabilities: a metal-insulator transition, an antiferromagnetic instability and a structural instability specific of the CuO{sub 2} planes. (author).

  19. Study of [beta][sup +] and electron capture decay of [sup 76]Sr in [gamma]-[gamma] coincidence measurements

    Energy Technology Data Exchange (ETDEWEB)

    Adzic, P.R.; Zupancic, M.T.; Vukanovic, R.B.; Anicin, I.V.; Skoro, G.P.; Kukoc, A.H. (Institute of Nuclear Sciences Vinca' ' , POB 522, 11001 Belgrade (Yugoslavia)); Lindroos, M.; Tengblad, O.; Veskovic, M.; ISOLDE Collaboration (CERN, PPE Division, CH-1211 Geneva 23 (Switzerland))

    1993-12-01

    The main goal of this work is to establish the nuclear decay scheme of [sup 76]Sr and energy levels of its doubly odd daughter nucleus [sup 76]Rb. The extremely neutron deficient nucleus [sup 76]Sr lying at the [ital N]=[ital Z] (=38) line with half-life of 8.9 s was produced in spallation reactions of 600 MeV protons from the CERN Synchrocyclotron (SC) with a Nb multifoil target in conjunction with a W surface ionization source at the ISOLDE facility. The [gamma]-spectroscopy measurements have been performed with two Ge detectors which were positioned at about [plus minus]30[degree] respectively downstream to the [sup 76]Sr beam. The obtained singles and coincidence [gamma] spectra were used to determine energies and intensities of [gamma] lines assigned to the decay of [sup 76]Sr and to establish some details of the nuclear level configuration of its daughter nucleus [sup 76]Rb up to 1000 keV.

  20. Nuclear structure investigations of 84Sr and 86Sr using γ-ray spectroscopic methods

    Science.gov (United States)

    Duckwitz, H.; Petkov, P.; Thomas, T.; Ahn, T.; Blazhev, A.; Cooper, N.; Fransen, C.; Hinton, M.; Ilie, G.; Jolie, J.; Werner, V.

    2017-09-01

    To investigate the low-spin structure of 84Sr and 86Sr, two fusion-evaporation experiments using the (p,2n) reaction have been performed. The data have been evaluated in terms of γ-ray spectroscopy, i.e. the level scheme was built up, branching intensities were determined, nuclear state spin and parity assignments were made after γγ angular correlation analyses. The previously known level scheme information was extended. In addition, lifetimes were determined by means of the Doppler Shift Attenuation Method (DSAM). In 86Sr, a new method for lifetime determinations, the Spectral Difference Method (SDM), was applied for the first time. In cases where all necessary input variables were known, reduced transition strengths were calculated with Monte Carlo simulated probability density functions. It is stressed that linear error propagation for the calculated errors of reduced transition strengths is not universally applicable. As both nuclei lie in the vicinity of the N=50 neutron shell closure and on a possible proton subshell closure of the 2p3/2 orbital at Z=38, Nuclear Shell Model calculations for 84Sr, 86Sr, and 88Sr have been performed in the truncated (2p3/2, 1f5/2, 2p1/2, 1g9/2) model space for protons and neutrons with the empirical JUN45 residual interaction. The comparison between experimental results and theoretical predictions show a large degree of consistency.

  1. High-precision mass measurements of neutron-deficient Tl isotopes at ISOLTRAP and the development of an ultra-stable voltage source for the PENTATRAP experiment

    Energy Technology Data Exchange (ETDEWEB)

    Boehm, Christine

    2015-01-14

    Atomic masses and hence binding energies of nuclides are of great importance for studies of nuclear structure since they reflect all effective interactions in a nucleus. Within this thesis the masses of seven nuclides, namely {sup 194}Au, {sup 194}Hg, {sup 190,193,198}Tl and {sup 202,208}Pb, were determined at the Penning-trap mass spectrometer ISOLTRAP at ISOLDE/CERN. The thallium region in the chart of isotopes is of special interest due to the occurrence of nuclear structure effects like low-lying isomers, level inversion, shape coexistence and deformations. These effects are investigated by applying finite-difference mass formulas, such as the two-neutron separation energies or the so-called empirical pairing gaps. The second topic addressed within the present thesis is an ultra-stable voltage source, called StaReP (Stable Reference for Penning Trap Experiments), which was developed at the Max-Planck-Institut fuer Kernphysik. It is one of the key components of the high-precision mass spectrometer PENTATRAP, containing a tower of five Penning traps. A 25-channel voltage source with a relative stability of few 10{sup -8} over a period of 10 minutes in the range of 0 to -100V is mandatory for PENTATRAP aiming for mass measurements with relative mass uncertainties of ≤ 10{sup -11}. Mass values with such a high precision allow for stringent tests of quantum electrodynamics in strong electric fields, testing Einstein's mass-energy relation E = mc{sup 2} as well as measurements of decay energies (Q-values) with applications in neutrino physics.

  2. SrMo0.9Co0.1O3-δ: A potential anode for intermediate-temperature solid-oxide fuel cells (IT-SOFC)

    Science.gov (United States)

    Martínez-Coronado, R.; Alonso, J. A.; Fernández-Díaz, M. T.

    2014-07-01

    SrMo0.9Co0.1O3-δ oxide has been prepared, characterized and tested as anode material in single solid-oxide fuel cells (SOFC), yielding output powers close to 800 mW cm-2 at 850 °C with pure H2 as a fuel. This excellent performance is accounted for the results of an "in-situ" neutron powder diffraction (NPD) experiment, at the working conditions of a SOFC, showing the presence of a sufficiently high oxygen deficiency, with large displacement factors for oxygen atoms that suggest a large lability and mobility, combined with a huge metal-like electronic conductivity, as high as 386 S cm-1 at T = 50 °C. Besides, the oxidation of the perovskite gives rise to a new oxygen deficient scheelite-like phase with formula SrMo0.9Co0.1O4-δ with Mo(VI), which has been studied by NPD and thermal analysis as far as crystal structure and composition are concerned. An adequate thermal expansion coefficient for both (oxidized and reduced) phases, an excellent reversibility upon cycling in oxidizing-reducing atmospheres and a good chemical compatibility with the electrolyte (La0.8Sr0.2Ga0.83Mg0.17O3-δ; LSGM) make this oxide a good candidate for anode in intermediate-temperature SOFC (IT-SOFCs).

  3. Neutron Repulsion

    OpenAIRE

    Manuel, Oliver K.

    2011-01-01

    Earth is connected gravitationally, magnetically and electrically to its heat source - a neutron star that is obscured from view by waste products in the photosphere. Neutron repulsion is like the hot filament in an incandescent light bulb. Excited neutrons are emitted from the solar core and decay into hydrogen that glows in the photosphere like a frosted light bulb. Neutron repulsion was recognized in nuclear rest mass data in 2000 as the overlooked source of energy, the keystone of an arch...

  4. Novel Mg-Doped SrMoO3 Perovskites Designed as Anode Materials for Solid Oxide Fuel Cells

    Directory of Open Access Journals (Sweden)

    Vanessa Cascos

    2016-07-01

    Full Text Available SrMo1−xMxO3−δ (M = Fe and Cr, x = 0.1 and 0.2 oxides have been recently described as excellent anode materials for solid oxide fuel cells at intermediate temperatures (IT-SOFC with LSGM as the electrolyte. In this work, we have improved their properties by doping with aliovalent Mg ions at the B-site of the parent SrMoO3 perovskite. SrMo1−xMgxO3−δ (x = 0.1, 0.2 oxides have been prepared, characterized and tested as anode materials in single solid-oxide fuel cells, yielding output powers near 900 mW/cm−2 at 850 °C using pure H2 as fuel. We have studied its crystal structure with an “in situ” neutron power diffraction (NPD experiment at temperatures as high as 800 °C, emulating the working conditions of an SOFC. Adequately high oxygen deficiencies, observed by NPD, together with elevated disk-shaped anisotropic displacement factors suggest a high ionic conductivity at the working temperatures. Furthermore, thermal expansion measurements, chemical compatibility with the LSGM electrolyte, electronic conductivity and reversibility upon cycling in oxidizing-reducing atmospheres have been carried out to find out the correlation between the excellent performance as an anode and the structural features.

  5. Insight into the structure and functional application of the Sr0.95Ce0.05CoO3-δ cathode for solid oxide fuel cells.

    Science.gov (United States)

    Yang, Wei; Zhang, Huairuo; Sun, Chunwen; Liu, Lilu; Alonso, J A; Fernández-Díaz, M T; Chen, Liquan

    2015-04-06

    A new perovskite cathode, Sr0.95Ce0.05CoO3-δ, performs well for oxygen-reduction reactions in solid oxide fuel cells (SOFCs). We gain insight into the crystal structure of Sr1-xCexCoO3-δ (x = 0.05, 0.1) and temperature-dependent structural evolution of Sr0.95Ce0.05CoO3-δ by X-ray diffraction, neutron powder diffraction, and scanning transmission electron microscopy experiments. Sr0.9Ce0.1CoO3-δ shows a perfectly cubic structure (a = a0), with a large oxygen deficiency in a single oxygen site; however, Sr0.95Ce0.05CoO3-δ exhibits a tetragonal perovskite superstructure with a double c axis, defined in the P4/mmm space group, that contains two crystallographically different cobalt positions, with distinct oxygen environments. The structural evolution of Sr0.95Ce0.05CoO3-δ at high temperatures was further studied by in situ temperature-dependent NPD experiments. At 1100 K, the oxygen atoms in Sr0.95Ce0.05CoO3-δ show large and highly anisotropic displacement factors, suggesting a significant ionic mobility. The test cell with a La0.8Sr0.2Ga0.83Mg0.17O3-δ-electrolyte-supported (∼300 μm thickness) configuration yields peak power densities of 0.25 and 0.48 W cm(-2) at temperatures of 1023 and 1073 K, respectively, with pure H2 as the fuel and ambient air as the oxidant. The electrochemical impedance spectra evolution with time of the symmetric cathode fuel cell measured at 1073 K shows that the Sr0.95Ce0.05CoO3-δ cathode possesses superior ORR catalytic activity and long-term stability. Mixed ionic-electronic conduction properties of Sr0.95Ce0.05CoO3-δ account for its good performance as an oxygen-reduction catalyst.

  6. Neutron Radiography

    Science.gov (United States)

    Heller, A. K.; Brenizer, J. S.

    Neutron radiography and its related two-dimensional (2D) neutron imaging techniques have been established as invaluable nondestructive inspection methods and quantitative measurement tools. They have been used in a wide variety of applications ranging from inspection of aircraft engine turbine blades to study of two-phase fluid flow in operating proton exchange membrane fuel cells. Neutron radiography is similar to X-ray radiography in that the method produces a 2D attenuation map of neutron radiation that has penetrated the object being examined. However, the images produced differ and are often complementary due to the differences between X-ray and neutron interaction mechanisms. The uses and types of 2D neutron imaging have expanded over the past 15 years as a result of advances in imaging technology and improvements in neutron generators/sources and computers. Still, high-intensity sources such as those from reactors and spallation neutron sources, together with conventional film radiography, remain the mainstay of high-resolution, large field-of-view neutron imaging. This chapter presents a summary of the history, methods, and related variations of neutron radiography techniques.

  7. Upper limit to magnetism in LaAlO3/SrTiO3 heterostructures

    NARCIS (Netherlands)

    Fitzsimmons, M.R.; Hengartner, N.W.; Singh, S.; Zhernenkov, M.; Bruno, F.Y.; Santamaria, J.; Brinkman, Alexander; Huijben, Mark; Molegraaf, Hajo; de la Venta, J.; Schuller, Ivan K.

    2011-01-01

    Using polarized neutron reflectometry we measured the neutron spin-dependent reflectivity from four LaAlO3/SrTiO3 superlattices. Our results imply that the upper limit for the magnetization averaged over the lateral dimensions of the sample induced by an 11 T magnetic field at 1.7 K is less than 2 G

  8. Fusion neutronics

    CERN Document Server

    Wu, Yican

    2017-01-01

    This book provides a systematic and comprehensive introduction to fusion neutronics, covering all key topics from the fundamental theories and methodologies, as well as a wide range of fusion system designs and experiments. It is the first-ever book focusing on the subject of fusion neutronics research. Compared with other nuclear devices such as fission reactors and accelerators, fusion systems are normally characterized by their complex geometry and nuclear physics, which entail new challenges for neutronics such as complicated modeling, deep penetration, low simulation efficiency, multi-physics coupling, etc. The book focuses on the neutronics characteristics of fusion systems and introduces a series of theories and methodologies that were developed to address the challenges of fusion neutronics, and which have since been widely applied all over the world. Further, it introduces readers to neutronics design’s unique principles and procedures, experimental methodologies and technologies for fusion systems...

  9. Iodine Deficiency

    Science.gov (United States)

    ... 2017 By ATA | Featured , Iodine Deficiency , News Releases , Potassium Iodide (KI) | No Comments IDD NEWSLETTER – February 2017 VOLUME ... 2016 By ATA | Featured , Iodine Deficiency , News Releases , Potassium Iodide (KI) | No Comments IDD NEWSLETTER – November 2015 (PDF ...

  10. Neutron Albedo

    CERN Document Server

    Ignatovich, V K

    2005-01-01

    A new, algebraic, method is applied to calculation of neutron albedo from substance to check the claim that use of ultradispersive fuel and moderator of an active core can help to gain in size and mass of the reactor. In a model of isotropic distribution of incident and reflected neutrons it is shown that coherent scattering on separate grains in the case of thermal neutrons increases transport cross section negligibly, however it decreases albedo from a wall of finite thickness because of decrease of substance density. A visible increase of albedo takes place only for neutrons with wave length of the order of the size of a single grain.

  11. Proton core polarization in low-lying states of 86Sr

    Science.gov (United States)

    Connelly, J. P.; Milliman, T. E.; Heisenberg, J. H.; Hersman, F. W.; Wise, J. E., III; Papanicolas, C. N.

    1990-11-01

    Electron-scattering cross sections, measured between 0.4 and 3.1 fm-1, have been unfolded to obtain charge transition densities for the low-lying 2+, 4+, 6+, and 8+ states in 86Sr. A comparison is made to analogous levels in 92Mo. Angular momentum recoupling in the 1g9/2 shell of two protons in 92Mo and two neutron holes in 86Sr are the dominant configurations for these levels. Proton core polarization in 86Sr neutron valence transitions diminishes with increasing multipolarity, indicating the residual interaction weakens with increasing momentum transfer.

  12. Diversity of abundance patterns of neutron-capture elements in very metal-poor stars

    Science.gov (United States)

    Aoki, Misa; Aoki, Wako; Ishimaru, Yuhri; Wanajo, Shinya

    2014-05-01

    Observations of Very Metal-Poor stars indicate that there are at least two sites to r-process; "weak r-process" and "main r-process". A question is whether these two are well separated or there exists a variation in the r-process. We present the results of abundance analysis of neutron-capture elements in the two Very Metal-Poor stars HD107752 and HD110184 in the Milky Way halo observed with the Subaru Telescope HDS. The abundance patterns show overabundace at light n-capture elements (e.g. Sr, Y), inferring the element yielding of weak r-process, while heavy neutron-capture elements (e.g. Ba, Eu) are deficient; however, the overabundance of light ones is not as significant as that previously found in stars representing the weak r-process (e.g. HD122563; Honda et al. 2006). Our study show diversity in the abundance patterns from light to heavy neutron-capture elements in VMP stars, suggesting a variation in r-process, which may depend on electron fraction of environment.

  13. Diversity of abundance patterns of neutron-capture elements in very metal-poor stars

    Energy Technology Data Exchange (ETDEWEB)

    Aoki, Misa; Ishimaru, Yuhri [International Christian University 10-2, Osawa, Mitaka, Tokyo 181-0015 (Japan); Aoki, Wako; Wanajo, Shinya [National Astronomical Observatory of Japan (NAOJ) 2-21-1, Osawa, Mitaka, Tokyo 181-8588 (Japan)

    2014-05-02

    Observations of Very Metal-Poor stars indicate that there are at least two sites to r-process; “weak r-process” and “main r-process”. A question is whether these two are well separated or there exists a variation in the r-process. We present the results of abundance analysis of neutron-capture elements in the two Very Metal-Poor stars HD107752 and HD110184 in the Milky Way halo observed with the Subaru Telescope HDS. The abundance patterns show overabundace at light n-capture elements (e.g. Sr, Y), inferring the element yielding of weak r-process, while heavy neutron-capture elements (e.g. Ba, Eu) are deficient; however, the overabundance of light ones is not as significant as that previously found in stars representing the weak r-process (e.g. HD122563; Honda et al. 2006). Our study show diversity in the abundance patterns from light to heavy neutron-capture elements in VMP stars, suggesting a variation in r-process, which may depend on electron fraction of environment.

  14. Raman, FTIR, photoacoustic-infrared, and inelastic neutron scattering spectra of ternary metal hydride salts A2MH5, (A = Ca, Sr, Eu; M = Ir, Rh) and their deuterides.

    Science.gov (United States)

    Barsan, Mirela M; Butler, Ian S; Gilson, Denis F R; Moyer, Ralph O; Zhou, Wei; Wu, Hui; Udovic, Terrence J

    2012-03-15

    The vibrational spectra of the ternary metal hydride (deuteride) salts, A(2)MH(5) and A(2)MD(5), where A = calcium, strontium and europium and M = iridium(I) and rhodium(I), have been assigned using Raman, Fourier transform infrared, photoacoustic infrared, and inelastic neutron scattering spectroscopies and density functional theory (DFT) calculations. The wavenumbers of the infrared-active stretching vibrations depend upon the ionization energies of the central metal atom and the cation. The phase transition in calcium pentahydridoiridate(I) was studied as a function of temperature and pressure.

  15. Neutron dosimetry; Dosimetria de neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Fratin, Luciano

    1993-12-31

    A neutron irradiation facility was designed and built in order to establish a procedure for calibrating neutron monitors and dosemeters. A 185 GBq {sup 241} Am Be source of known is used as a reference source. The irradiation facility using this source in the air provides neutron dose rates between 9 nSv s{sup -1} and 0,5 {sup {mu}}Sv s{sup -1}. A calibrated 50 nSv s{sup -1} thermal neutron field is obtained by using a specially designed paraffin block in conjunction with the {sup 241} Am Be source. A Bonner multisphere spectrometer was calibrated, using a procedure based on three methods proposed by international standards. The unfold {sup 241} Am Be neutron spectrum was determined from the Bonner spheres data and resulted in a good agreement with expected values for fluence rate, dose rate and mean energy. A dosimetric system based on the electrochemical etching of CR-39 was developed for personal dosimetry. The dosemeter badge using a (n,{alpha}) converter, the etching chamber and high frequency power supply were designed and built specially for this project. The electrochemical etching (ECE) parameters used were: a 6N KOH solution, 59 deg C, 20 kV{sub pp} cm{sup -1}, 2,0 kHz, 3 hours of ECE for thermal and intermediate neutrons and 6 hours for fast neutrons. The calibration factors for thermal, intermediate and fast neutrons were determined for this personal dosemeter. The sensitivities determined for the developed dosimetric system were (1,46{+-} 0,09) 10{sup 4} tracks cm{sup -2} mSv{sup -1} for thermal neutrons, (9{+-}3) 10{sup 2} tracks cm{sup -2} mSV{sup -1} for intermediate neutrons and (26{+-}4) tracks cm{sup -2} mSv{sup -1} for fast neutrons. The lower and upper limits of detection were respectively 0,002 mSv and 0,6 mSv for thermal neutrons, 0,04 mSv and 8 mSv for intermediate neutrons and 1 mSv and 12 mSv for fast neutrons. In view of the 1990`s ICRP recommendations, it is possible to conclude that the personal dosemeter described in this work is

  16. Neutron reflectometry

    DEFF Research Database (Denmark)

    Klösgen-Buchkremer, Beate Maria

    2014-01-01

    films or films with magnetic properties. The reason is the peculiar property of neutron light since the mass of a neutron is close to the one of a proton, and since it bears a magnetic moment. The optical properties of matter, when interacting with neutrons, are described by a refractive index......Neutron (and X-ray) reflectometry constitute complementary interfacially sensitive techniques that open access to studying the structure within thin films of both soft and hard condensed matter. Film thickness starts oxide surfaces on bulk substrates, proceeding to (pauci-)molecular layers and up...... to hundreds of nanometers. Thickness resolution for flat surfaces is in the range of few Ǻngstrøm, and as a peculiar benefit, the presence and properties of buried interfaces are accessible. Focus here will be on neutron reflectometry, a technique that is unique in applications involving composite organic...

  17. Crystal growth and evaluation of scintillation properties of Eu and alkali-metal co-doped LiSrAlF{sub 6} single crystals for thermal neutron detector

    Energy Technology Data Exchange (ETDEWEB)

    Wakahara, Shingo; Yokota, Yuui; Yamaji, Akihiro; Fujimoto, Yutaka; Sugiyama, Makoto; Kurosawa, Shunsuke [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Yanagida, Takayuki [New Industry Creation Hatchery Center (NICHe), 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Pejchal, Jan [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Institute of Physics AS CR, Cukrovarnicka 10, Prague 16253 (Czech Republic); Kawaguchi, Noriaki [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Tokuyama, Co. Ltd., Shibuya 3-chome, Shibuya-ku, Tokyo 150-8383 (Japan); Fukuda, Kentaro [Tokuyama, Co. Ltd., Shibuya 3-chome, Shibuya-ku, Tokyo 150-8383 (Japan); Yoshikawa, Akira [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); New Industry Creation Hatchery Center (NICHe), 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan)

    2012-12-15

    In recent work, Na co-doping have found to improve the light output of Eu doped LiCaAlF{sub 6} (Eu:LiCAF) for thermal neutron scintillator. We grew Eu 2% and alkali metal 1% co-doped LiSAF crystals by Micro-Pulling down method to understand the effect of alkali metal co-doping on scintillation properties and mechanism compared with LiCAF. In photo- and {alpha}-ray induced radio-luminescence spectra of the all grown crystals, the emissions from d-f transition of Eu{sup 2+} were observed. Without relation to excitation source, decay times of co-doped LiSAF were longer than Eu only doped one. The light yield of Na, K and Cs co-doped LiSAF under {sup 252}Cf neutron excitation were improved. Especially, K co-doped Eu:LiSAF reached 33200 ph/n, which outperformed Eu only doped one by approximately 20% (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  18. Study of Neutron Deficient ^9C

    Science.gov (United States)

    Belarge, Joseph; Rogachev, G. V.; Blackmon, J.; Wiedenhover, I.; Baby, L.; Johnson, E. D.; Kuchera, A. N.; Koshchiy, E.; Lai, J.; Linhardt, L.; Macon, K.; Matos, M.; Santiago-Gonzalez, D.

    2012-10-01

    Development of theoretical framework that allows the combination of nuclear structure calculations with the continuum is an important objective of modern nuclear theory [1,2]. Due to the low binding energy of exotic isotopes even the lowest excited states are unbound and therefore it is essential to take the continuum into account. We studied the structure of the lightest bound carbon isotope, ^9C, through ^8B+p resonance scattering using the new active target detector ANASEN [3]. The experiment was performed at the John D. Fox Superconducting Accelerator Laboratory at FSU. A rare isotope beam of ^8B ions was produced using the radioactive nuclear beam facility RESOLUT. Pure hydrogen gas was used as a target and also as an active medium for the gas proportional counters of the ANASEN detector. The analysis of the p+^8B excitation functions was performed using the R-Matrix approach. The preliminary results will be presented.[4pt] [1] A. Volya, Phys. Rev. C 79, 044308 (2009).[0pt] [2] S. Quaglioni and P. Navr'atil, PRL 101, 092501 (2008).[0pt] [3] M. Matos, et al.,Proc. Intern. Symposium on Nuclei in the Cosmos XI, July 19-23 2010, Heidelberg, Germany, p.226(2010).

  19. Study of Neutron Deficient 13O

    Science.gov (United States)

    Belarge, Joseph; Rogachev, G. V.; Blackmon, J.; Wiedenhover, I.; Baby, L.; Johnson, E. D.; Kuchera, A. N.; Koshchiy, E.; Lai, J.; Linhardt, L.; Macon, K.; Matos, M.; Santiago-Gonzalez, D.

    2013-10-01

    Development of theoretical framework that allows the combination of nuclear structure calculations with the continuum is an important objective of modern nuclear theory [A. Volya, PRC 79, 044308 (2009), S. Quaglioni and P. Navratil, PRL 101092501 (2008)]. Due to the low binding energy of exotic isotopes even the lowest excited states are unbound and therefore it is essential to take the continuum into account. We studied the structure of the lightest bound oxygen isotope, 13O, through 12N+p resonance scattering using the new active target detector ANASEN [M. Matos et al., Proc. Intern. Symp. on Nuclei in the Cosmos, July 19-23, Heidelberg, Germany, p. 226 (2010)]. The experiment was performed at the John D. Fox Superconducting Accelerator Laboratory at Florida State University. A rare isotope beam of 12N ions was produced using the radioactive nuclear beam facility RESOLUT. Methane gas was used as a target and also as an active medium for the gas proportional counters of the ANASEN detector. The analysis of the p+12N excitation functions was performed using the R-Matrix approach. The preliminary results of the experiment will be presented.

  20. Disaccharidase deficiency.

    Science.gov (United States)

    Bayless, T M; Christopher, N L

    1969-02-01

    This review of the literature and current knowledge concerning a nutritional disorder of disaccharidase deficiency discusses the following topics: 1) a description of disorders of disaccharide digestion; 2) some historical perspective on the laboratory and bedside advances in the past 10 years that have helped define a group of these digestive disorders; 3) a classification of conditions causing disaccharide intolerance; and 4) a discussion of some of the specific clinical syndromes emphasizing nutritional consequences of these syndromes. The syndromes described include congenital lactase deficiency, acquired lactase deficiency in teenagers and adults, acquired generalized disaccharidase deficiency secondary to diffuse mucosal damage, acquired lactose intolerance secondary to alterations in the intestinal transit, sucrase-isomaltase deficiencies, and other disease associations connected with lactase deficiency such as colitis.

  1. Solar neutron emissivity during the large flare on 1982 June 3

    Science.gov (United States)

    Chupp, E. L.; Forrest, D. J.; Kanbach, G.; Flueckiger, E.; Golliez, F.

    1987-01-01

    For the solar neutron event on June 3, 1982, it is shown here that the combined SMM Gamma Ray Spectrometer and Jungfraujoch neutron monitor data require a time-extended emission of neutrons at the sun with energies of 100 MeV to about 2 GeV. The solar neutron emissivity spectrum is shown to have a strong downward curvature or truncation between 2 and 4 GeV. A Bessel function and truncated power law give acceptable fits to the observational data, but only the power law can explain the rapid rise of the neutron monitor count rate. The integrated emissivity of neutrons above E(n) of 100 MeV is strongly constrained at 8 x 10 to the 28th neutrons/sr and is essentially independent of neutron spectral shape. At neutron energies of about 100 MeV, good agreement is found for both spectral forms with observations of neutron decay protons.

  2. Defect-induced ferromagnetism in crystalline SrTiO3

    Energy Technology Data Exchange (ETDEWEB)

    Osten, Julia; Potzger, Kay; Shalimov, Artem; Talut, Georg; Reuther, Helfried; Arpaci, Seda; Buerger, Danilo; Schmidt, Heidemarie [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstrasse 400, 01328 Dresden (Germany); Levin, Alexander.A. [Institut fuer Strukturphysik, Technische Universitaet Dresden, 01062 (Germany); Nestler, Tina; Meyer, Dirk C. [Institut fuer Experimentelle Physik, Technische Universitaet Bergakademie Freiberg, 09596 Freiberg (Germany)

    2011-07-01

    Ion irradiation of high-quality SrTiO3 single crystals leads to room-temperature ferromagnetism. Structural analysis revealed oxygen deficient (polycrystalline) SrTiO3, Sr2Ti6O13, or Ruddlesden-Popper like secondary phases at the sample surface induced by the irradiation. The lack of potentially ferromagnetic secondary phases suggests defects to be the origin of the observed ferromagnetic signal.

  3. Neutrons production on the IPHI accelerator for the validation of the design of the compact neutron source SONATE

    CERN Document Server

    Menelle, Alain; Prunes, Fabien; Homatter, Benoit; Annighöfer, Burkhard; Porcher, Florence; Chauvin, Nicolas; Schwindling, Jérôme; Letourneau, Alain; Marchix, Anthony; Tran, Ngoc-Hoang

    2016-01-01

    We aim at building an accelerator based compact neutron source which would provide a thermal neutron flux on the order of 4E12 n.s-1.cm-2.sr-1. Such brilliance would put compact neutron sources on par with existing medium flux neutron research reactors. We performed the first neutron production tests on the IPHI proton accelerator at Saclay. The neutron fluxes were measured using gold foil activation and 3He detectors. The measured fluxes were compared with MCNP and GEANT4 Monte Carlo simulations in which the whole experimental setup was modelled. There is a good agreement between the experimental measurements and the Monte-Carlo simulations. The available modelling tools will allow us to optimize the whole Target Moderator Reflector assembly together with the neutron scattering spectrometer geometries.

  4. Influence of Phase Transformations on Crystal Growth of Stoichiometric Brownmillerite Oxides: Sr2ScGaO5 and Ca2Fe2O5

    Directory of Open Access Journals (Sweden)

    Monica Ceretti

    2016-11-01

    Full Text Available High quality stoichiometric brownmillerite-type oxide single crystals have been successfully grown by the floating zone method using a mirror furnace. We report here on the growth conditions and structural characterization of two model compounds: Ca2Fe2O5 and Sr2ScGaO5. Both show oxygen deficiency with respect to the average perovskite structure, and are promising candidates for oxygen ion conductivity at moderate temperatures. While Sr2ScGaO5 single crystals were obtained in the cubic oxygen-deficient perovskite structure, Ca2Fe2O5 crystallizes in the brownmillerite framework. Having no cubic parent high temperature counterpart, Ca2Fe2O5 crystals were found to be not twinned. We report on structural characterization of the as-grown single crystals by neutron and X-ray diffraction, as well as scanning electron microscopy (SEM coupled with EDX (Energy Dispersive X-Ray Spectroscopy analysis and isotope exchange experiments.

  5. Ferromagnetic erbium studied by {mu}SR

    Energy Technology Data Exchange (ETDEWEB)

    Hartmann, O. [Uppsala Univ. (Sweden). Dept. of Theoretical Physics; Lidstroem, E. [Uppsala Univ. (Sweden). Dept. of Theoretical Physics; Ekstroem, M. [Uppsala Univ. (Sweden). Dept. of Theoretical Physics; Waeppling, R. [Uppsala Univ. (Sweden). Dept. of Theoretical Physics; Asch, L. [Technische Univ. Muenchen, Garching (Germany). Physik-Department; Kalvius, G.M. [Technische Univ. Muenchen, Garching (Germany). Physik-Department

    1997-04-01

    The ferromagnetic cone phase of erbium has been studied with {mu}SR. Two processing muon signals were observed with nearly equal intensities at T {approx} 15 K. At lower temperatures, one of the signals is gradually reduced and disappeared below 5 K. The two observed muon frequencies and their depolarisation behaviour show that the magnetic structure deduced from neutron and X-ray scattering must be modified and that a ``squaring up`` of the structure is likely to occur as the temperature is lowered. (orig.).

  6. Ferromagnetic erbium studied by {mu}SR

    Energy Technology Data Exchange (ETDEWEB)

    Hartmann, Ola; Lidstroem, Erik; Ekstroem, Mikael; Waeppling, Roger [Uppsala University, Department of Physics (Sweden); Asch, L.; Kalvius, G.M. [TU Muenich, Physics Department (Germany)

    1997-04-15

    The ferromagnetic cone phase of erbium has been studied with {mu}SR. Two precessing muon signals were observed with nearly equal intensities at T {approx} 15 K. At lower temperatures, one of the signals is gradually reduced and disappeared below 5 K. The two observed muon frequencies and their depolarisation behaviour show that the magnetic structure deduced from neutron and X-ray scattering must be modified and that a 'squaring up' of the structure is likely to occur as the temperature is lowered.

  7. Evidence for SrHo2O4 and SrDy2O4 as model J1-J2 zigzag chain materials

    DEFF Research Database (Denmark)

    Fennell, A.; Pomjakushin, V. Y.; Uldry, A.

    2014-01-01

    Neutron diffraction and inelastic spectroscopy is used to characterize the magnetic Hamiltonian of SrHo2O4 and SrDy2O4. Through a detailed computation of the crystal-field levels we find site-dependent anisotropic single-ion magnetism in both materials, and diffraction measurements show the prese...

  8. Prolidase deficiency

    Directory of Open Access Journals (Sweden)

    Masood Qazi

    2007-01-01

    Full Text Available Prolidase deficiency is a rare inborn disorder of collagen metabolism characterized by chronic recurrent skin ulceration. A seven-year-old girl and her younger sibling with clinical features and laboratory criteria fulfilling the diagnosis of prolidase deficiency are presented in view of rarity of the condition.

  9. Iodine Deficiency

    NARCIS (Netherlands)

    Zimmermann, M.B.

    2009-01-01

    Iodine deficiency has multiple adverse effects in humans, termed iodine deficiency disorders, due to inadequate thyroid hormone production. Globally, it is estimated that 2 billion individuals have an insufficient iodine intake, and South Asia and sub-Saharan Africa are particularly affected. Howeve

  10. Iodine Deficiency

    NARCIS (Netherlands)

    Zimmermann, M.B.

    2009-01-01

    Iodine deficiency has multiple adverse effects in humans, termed iodine deficiency disorders, due to inadequate thyroid hormone production. Globally, it is estimated that 2 billion individuals have an insufficient iodine intake, and South Asia and sub-Saharan Africa are particularly affected. Howeve

  11. Magnetic properties and crystal structure of Sr3CoIrO6 and Sr3NiIrO6

    Science.gov (United States)

    Mikhailova, D.; Schwarz, B.; Senyshyn, A.; Bell, A. M. T.; Skourski, Y.; Ehrenberg, H.; Tsirlin, A. A.; Agrestini, S.; Rotter, M.; Reichel, P.; Chen, J. M.; Hu, Z.; Li, Z. M.; Li, Z. F.; Tjeng, L. H.

    2012-10-01

    We have studied the magnetic properties and crystal structure of Sr3CoIrO6 and Sr3NiIrO6 as a function of temperature. Two characteristic temperatures, T1=90 K and T2=25 K for Sr3CoIrO6, and T1=85 K and T2=15 K for Sr3NiIrO6, were observed. Below T1 a significant increase of magnetization and below T2 a weak temperature dependence of magnetization in the field-cooled and practically zero magnetization values in the zero-field-cooled mode were detected for both compounds. The existence of Ir4+ in Sr3CoIrO6 was confirmed by an Ir-LIII x-ray absorption measurement. Magnetoelastic effects have been observed in the temperature dependence of the lattice parameters of Sr3CoIrO6 and Sr3NiIrO6. The magnetic structure of Sr3CoIrO6 in zero fields can be described as a commensurate modulated antiferromagnet with a propagation vector k=(0,0,1). Neutron powder diffraction with polarized neutrons gave evidence of short-range magnetic order, above and below the magnetic ordering temperature.

  12. Charge, neutron, and weak size of the atomic nucleus

    CERN Document Server

    Hagen, G; Forssén, C; Jansen, G R; Nazarewicz, W; Papenbrock, T; Wendt, K A; Bacca, S; Barnea, N; Carlsson, B; Drischler, C; Hebeler, K; Hjorth-Jensen, M; Miorelli, M; Orlandini, G; Schwenk, A; Simonis, J

    2015-01-01

    What is the size of the atomic nucleus? This deceivably simple question is difficult to answer. While the electric charge distributions in atomic nuclei were measured accurately already half a century ago, our knowledge of the distribution of neutrons is still deficient. In addition to constraining the size of atomic nuclei, the neutron distribution also impacts the number of nuclei that can exist and the size of neutron stars. We present an ab initio calculation of the neutron distribution of the neutron-rich nucleus $^{48}$Ca. We show that the neutron skin (difference between radii of neutron and proton distributions) is significantly smaller than previously thought. We also make predictions for the electric dipole polarizability and the weak form factor; both quantities are currently targeted by precision measurements. Based on ab initio results for $^{48}$Ca, we provide a constraint on the size of a neutron star.

  13. Investigation for the puzzling abundance pattern of the neutron-capture elements in the ultra metal-poor star: CS 30322-023

    CERN Document Server

    Cui, W Y; Ma, K; Zhang, L

    2007-01-01

    The s-enhanced and very metal-poor star CS 30322-023 shows a puzzling abundance pattern of the neutron-capture elements, i.e. several neutron-capture elements such as Ba, Pb etc. show enhancement, but other neutron-capture elements such as Sr, Eu etc. exhibit deficient with respect to iron. The study to this sample star could make people gain a better understanding of s- and r-process nucleosynthesis at low metallicity. Using a parametric model, we find that the abundance pattern of the neutron-capture elements could be best explained by a star that was polluted by an AGB star and the CS 30322-023 binary system formed in a molecular cloud which had never been polluted by r-process material. The lack of r-process material also indicates that the AGB companion cannot have undergone a type-1.5 supernova, and thus must have had an initial mass below 4.0M$_\\odot$, while the strong N overabundance and the absence of a strong C overabundance indicate that the companion's initial mass was larger than 2.0M$_\\odot$. Th...

  14. Neutron Therapy in the 21st Century

    CERN Document Server

    Kroc, Thomas K

    2014-01-01

    The question of whether or not neutron therapy works has been answered. It is a qualified yes, as is the case with all of radiation therapy. But, neutron therapy has not kept pace with the rest of radiation therapy in terms of beam delivery techniques. Modern photon and proton based external beam radiotherapy routinely implements image-guidance, beam intensity-modulation and 3-dimensional treatment planning. The current iteration of fast neutron radiotherapy does not. Addressing these deficiencies, however, is not a matter of technology or understanding, but resources. The future of neutron therapy lies in better understanding the interaction processes of radiation with living tissue. A combination of radiobiology and computer simulations is required in order to optimize the use of neutron therapy. The questions that need to be answered are: Can we connect the macroscopic with the microscopic? What is the optimum energy? What is the optimum energy spectrum? Can we map the sensitivity of the various tissues of...

  15. Neutron Repulsion

    CERN Document Server

    Manuel, Oliver K

    2011-01-01

    Earth is connected gravitationally, magnetically and electrically to its heat source - a neutron star that is obscured from view by waste products in the photosphere. Neutron repulsion is like the hot filament in an incandescent light bulb. Excited neutrons are emitted from the solar core and decay into hydrogen that glows in the photosphere like a frosted light bulb. Neutron repulsion was recognized in nuclear rest mass data in 2000 as the overlooked source of energy, the keystone of an arch that locked together these puzzling space-age observations: 1.) Excess 136Xe accompanied primordial helium in the stellar debris that formed the solar system (Fig. 1); 2.) The Sun formed on the supernova core (Fig. 2); 3.) Waste products from the core pass through an iron-rich mantle, selectively carrying lighter elements and lighter isotopes of each element into the photosphere (Figs. 3-4); and 4.) Neutron repulsion powers the Sun and sustains life (Figs. 5-7). Together these findings offer a framework for understanding...

  16. Iodine Deficiency

    Science.gov (United States)

    ... 0 Iodine Daily Serving now recommended in Multivitamin/Mineral Supplements for Pregnant and Lactating Women By ATA | 2015 News Releases , Iodine Deficiency , News Releases , Thyroid Disease and Pregnancy | No Comments Falls Church, February 10, 2015 —The ...

  17. Iron deficiency.

    Science.gov (United States)

    Scrimshaw, N S

    1991-10-01

    The world's leading nutritional problem is iron deficiency. 66% of children and women aged 15-44 years in developing countries have it. Further, 10-20% of women of childbearing age in developed countries are anemic. Iron deficiency is identified with often irreversible impairment of a child's learning ability. It is also associated with low capacity for adults to work which reduces productivity. In addition, it impairs the immune system which reduces the body's ability to fight infection. Iron deficiency also lowers the metabolic rate and the body temperature when exposed to cold. Hemoglobin contains nearly 73% of the body's iron. This iron is always being recycled as more red blood cells are made. The rest of the needed iron does important tasks for the body, such as binds to molecules that are reservoirs of oxygen for muscle cells. This iron comes from our diet, especially meat. Even though some plants, such as spinach, are high in iron, the body can only absorb 1.4-7% of the iron in plants whereas it can absorb 20% of the iron in red meat. In many developing countries, the common vegetarian diets contribute to high rates of iron deficiency. Parasitic diseases and abnormal uterine bleeding also promote iron deficiency. Iron therapy in anemic children can often, but not always, improve behavior and cognitive performance. Iron deficiency during pregnancy often contributes to maternal and perinatal mortality. Yet treatment, if given to a child in time, can lead to normal growth and hinder infections. However, excess iron can be damaging. Too much supplemental iron in a malnourished child promotes fatal infections since the excess iron is available for the pathogens use. Many countries do not have an effective system for diagnosing, treating, and preventing iron deficiency. Therefore a concerted international effort is needed to eliminate iron deficiency in the world.

  18. Neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Heger, G. [Rheinisch-Westfaelische Technische Hochschule Aachen, Inst. fuer Kristallographie, Aachen (Germany)

    1996-12-31

    X-ray diffraction using conventional laboratory equipment and/or synchrotron installations is the most important method for structure analyses. The purpose of this paper is to discuss special cases, for which, in addition to this indispensable part, neutrons are required to solve structural problems. Even though the huge intensity of modern synchrotron sources allows in principle the study of magnetic X-ray scattering the investigation of magnetic structures is still one of the most important applications of neutron diffraction. (author) 15 figs., 1 tab., 10 refs.

  19. Biliary excretion of essential trace elements in rats under oxidative stress caused by selenium deficiency

    Energy Technology Data Exchange (ETDEWEB)

    Yamasaki, Kosuke; Tsukada, Masamichi [Meiji University, School of Agriculture, Kawasaki, Kanagawa (Japan); Sakuma, Yasunobu; Sasaki, Junya; Matsuoka, Keisuke; Honda, Chikako; Endo, Kazutoyo [Showa Pharmaceutical University, Department of Physical Chemistry, Machida, Tokyo (Japan); Matsumoto, Ken-ichiro; Anzai, Kazunori [National Institute of Radiological Science, Research Center for Charged Particle Therapy, Chiba (Japan); Enomoto, Shuichi [The Institute of Physical and Chemical Research (RIKEN), Radioisotope Technology Division, Cyclotron Center, Wako, Saitama (Japan); Okayama University, Department of Analytical Chemistry, School of Pharmacy, Okayama (Japan)

    2011-11-15

    The excretion of essential trace elements, namely, Se, Sr, As, Mn, Co, V, Fe, and Zn into the bile of Se-deficient (SeD) Wistar male rats was studied using the multitracer (MT) technique, and instrumental neutron activation analysis (INAA). Normal and Se-control (SeC) rat groups were used as reference groups to compare the effects of Se levels on the behaviors of the essential trace elements. The excretion (% dose) of Se, Sr, As, Mn, Co, and V increased with Se levels in the liver. The biliary excretion of Mn and As dramatically enhanced for SeC rats compared with SeD rats, while that of V accelerated a little for SeC rats. The radioactivity levels of {sup 59}Fe and {sup 65}Zn in the MT tracer solution were insufficient to measure their excretion into bile. The role of glutathione and bilirubin for biliary excretion of the metals was discussed in relation to Se levels in rat liver. (orig.)

  20. Neutronics of pulsed spallation neutron sources

    CERN Document Server

    Watanabe, N

    2003-01-01

    Various topics and issues on the neutronics of pulsed spallation neutron sources, mainly for neutron scattering experiments, are reviewed to give a wide circle of readers a better understanding of these sources in order to achieve a high neutronic performance. Starting from what neutrons are needed, what the spallation reaction is and how to produce slow-neutrons more efficiently, the outline of the target and moderator neutronics are explained. Various efforts with some new concepts or ideas have already been devoted to obtaining the highest possible slow-neutron intensity with desired pulse characteristics. This paper also reviews the recent progress of such efforts, mainly focused on moderator neutronics, since moderators are the final devices of a neutron source, which determine the source performance. Various governing parameters for neutron-pulse characteristics such as material issues, geometrical parameters (shape and dimensions), the target-moderator coupling scheme, the ortho-para-hydrogen ratio, po...

  1. In situ X-ray and neutron diffraction of the Ruddlesden–Popper compounds (RE2–xSrx)₀.₉₈(Fe₀.₈Co₀.₂)1–yMgyO4–δ (RE=La, Pr): Structure and CO₂ stability

    Energy Technology Data Exchange (ETDEWEB)

    Chatzichristodoulou, C., E-mail: ccha@dtu.dk [Department of Energy Conversion and Storage, Technical University of Denmark, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Hauback, B.C. [Institute for Energy Technology, P.O. Box 40, Kjeller NO-2027 (Norway); Hendriksen, P.V. [Department of Energy Conversion and Storage, Technical University of Denmark, Frederiksborgvej 399, DK-4000 Roskilde (Denmark)

    2013-05-01

    The crystal structure of the Ruddlesden–Popper compounds (La₁.₀Sr₁.₀)₀.₈Fe₁.₀Co₀.₂O4–δ and (La₁.₂Sr₀.₈)₀.₉₈(Fe₀.₈Co₀.₂)₀.₈Mg₀.₂O4–δ was investigated at 1000 °C in N₂ (aO₂=1×10₋₄ by in-situ powder neutron diffraction. In-situ powder X-ray diffraction (PXD) was also employed to investigate the temperature dependence of the lattice parameters of the compounds in air and the oxygen activity dependence of the lattice parameters at 800 °C and 1000 °C. The thermal and chemical expansion coefficients, determined along the two crystallographic directions of the tetragonal unit cell, are highly anisotropic. The equivalent pseudo-cubic thermal and chemical expansion coefficients are in agreement with values determined by dilatometry. The chemical stability in CO₂ containing environments of various Ruddlesden–Popper compounds with chemical formula (RE2-xSrx)₀.₉₈(Fe₀.₈Co₀.₂)1-yMgyO4–δ (RE=La, Pr), as well as their stability limit in H₂/H₂O=4.5 were also determined by in-situ PXD for x=0.9, 1.0 and y=0, 0.2. - Graphical abstract: Influence of electronic configuration on bond length, lattice parameters and anisotropic thermal and chemical expansion. Highlights: • The thermal and chemical expansion coefficients are largely anisotropic. • The expansion of the perovskite layers is constrained along the a direction. • The studied compositions show remarkable thermodynamic stability upon reduction. • The thermal and chemical expansion coefficients are lower than related perovskites. • The investigated materials decompose in CO₂ containing atmospheres.

  2. Neutron tomography

    Science.gov (United States)

    Crump, James C., III; Richards, Wade J.; Shields, Kevin C.

    1995-07-01

    The McClellan Nuclear Radiation Center's (MNRC) staff in conjunction with a Cooperative Research and Development Agreement (CRDA) with the U.C. Santa Barbara facility has developed a system that can be used for aircraft inspection of jet engine blades. The problem was to develop an inspection system that can detect very low concentrations of hydrogen (i.e., greater than 100 ppm) in metal matricies. Specifically in Titanium alloy jet engine blades. Entrapment and precipitation of hydrogen in metals is an undesirable phenomenon which occurs in many alloys of steel and titanium. In general, metals suffer a loss of mechanical properties after long exposures to hydrogen, especially at high temperatures and pressures, thereby becoming embrittled. Neutron radiography has been used as a nondestructive testing technique for many years. Neutrons, because of their unique interactions with materials, are especially useful in the detection of hydrogen. They have an extremely high interaction cross section for low atomic number nuclei (i.e., hydrogen). Thus hydrogen in a metal matrix can be visualized using neutrons. Traditional radiography is sensitive to the total attenuation integrated over the path of radiation through the material. Increased sensitivity and quantitative cross section resolution can be obtained using three-dimensional volumetric imaging techniques such as tomography. The solution used to solve the problem was to develop a neutron tomography system. The neutron source is the McClellan Nuclear Radiation Center's 1 MW TRIGA reactor. This paper describes the hardware used in the system as well as some of the preliminary results.

  3. Onset of collectivity in $^{96,98}$Sr studied via Coulomb excitation

    CERN Document Server

    Clement, E; Dijon, A; de France, G; Bastin, B; Blazhev, A; Bree, N; Butler, P; Delahaye, P; Ekstrom, A; Georgiev, G; Hasan, N; Iwanicki, J; Jenkins, D; Korten, W; Larsen, A C; Ljungvall, J; Moschner, K; Napiorkowski, P; Pakarinen, J; Petts, A; Renstrom, T; Seidlitz, M; Siem, S; Sotty, C; Srebrny, J; Stefanescu, I; Tveten, G M; Van de Walle, J; Warr, N; Wrzosek-Lipska, K; Zielinska, M; Bauer, C; Bruyneel, B; Butterworth, J; Fitzpatrick, C; Fransen, C; GernhäUser, R; Hess, H; Lutter, R; Marley, P; Reiter, P; Siebeck, B; Vermeulen, M; Wiens, A; De Witte, H

    2014-01-01

    A rapid onset of quadrupole deformation is known to occur around the neutron number 60 in the neutron-rich Zr and Sr isotopes. This shape change has made the neutron-rich A = 100 region an active area of experimental and theoretical studies for many decades now. We report in this contribution new experimental results in the neutron rich 96,98Sr investigated by safe Coulomb excitation of radioactive beams at the REX-ISOLDE facility, CERN. Reduced transition probabilities and spectroscopic quadrupole moments have been extracted from the differential Coulomb excitation cross section supporting the scenario of shape coexistence/change at N=60. Future perspectives are presented including the recent experimental campaign performed at ILL-Grenoble.

  4. Cobalamin deficiency.

    Science.gov (United States)

    Herrmann, Wolfgang; Obeid, Rima

    2012-01-01

    Cobalamin (Cbl, vitamin B12) consists of a corrinoid structure with cobalt in the centre of the molecule. Neither humans nor animals are able to synthesize this vitamin. Foods of animal source are the only natural source of cobalamin in human diet. There are only two enzymatic reactions in mammalian cells that require cobalamin as cofactor. Methylcobolamin is a cofactor for methionine synthase. The enzyme methylmalonyl-CoA-mutase requires adenosylcobalamin as a cofactor. Therefore, serum concentrations of homocysteine (tHcy) and methylmalonic acid (MMA) will increase in cobalamin deficiency. The cobalamin absorption from diet is a complex process that involves different proteins: haptocorrin, intrinsic factor and transcobalamin (TC). Cobalamin that is bound to TC is called holotranscobalamin (holoTC) which is the metabolically active vitamin B12 fraction. HoloTC consists 6 and 20% of total cobalamin whereas 80% of total serum cobalamin is bound to another binding protein, haptocorrin. Cobalamin deficiency is common worldwide. Cobalamin malabsorption is common in elderly subjects which might explain low vitamin status. Subjects who ingest low amount of cobalamin like vegetarians develop vitamin deficiency. No single parameter can be used to diagnose cobalamin deficiency. Total serum cobalamin is neither sensitive nor it is specific for cobalamin deficiency. This might explain why many deficient subjects would be overlooked by utilizing total cobalamin as status marker. Concentration of holotranscobalamin (holoTC) in serum is an earlier marker that becomes decreased before total serum cobalamin. Concentrations of MMA and tHcy increase in blood of cobalamin deficient subjects. Despite limitations of these markers in patients with renal dysfunction, concentrations of MMA and tHcy are useful functional markers of cobalamin status. The combined use of holoTC and MMA assays may better indicate cobalamin status than either of them. Because Cbl deficiency is a risk factor

  5. Spontaneous-fission decay properties and production cross-sections for the neutron-deficient nobelium isotopes formed in the sup 4 sup 4 sup , sup 4 sup 8 Ca+ sup 2 sup 0 sup 4 sup , sup 2 sup 0 sup 6 sup , sup 2 sup 0 sup 8 Pb reactions

    CERN Document Server

    Belozerov, A V; Chepigin, V I; Drobina, T P; Gorshkov, V A; Kabachenko, A P; Malyshev, O N; Merkin, I M; Oganessian, Yu T; Popeko, A G; Sagaidak, R N; Svirikhin, A I; Yeremin, A V; Berek, G; Brida, I; Sáro, S

    2003-01-01

    Heavy-ion fusion reactions sup 4 sup 8 Ca+ sup 2 sup 0 sup 4 Pb and sup 4 sup 4 Ca+ sup 2 sup 0 sup 8 Pb leading to the same compound nucleus sup 2 sup 5 sup 2 No sup * were run in attempts to produce new neutron-deficient spontaneous-fission isotopes of sup 2 sup 4 sup 9 sup , sup 2 sup 5 sup 0 No using the electrostatic separator VASSILISSA. Production cross-sections for the spontaneous-fission activities with the half-lives 5.6 and 54 mu s observed in these reactions are compared with the measured ones for the well-known isotopes of sup 2 sup 5 sup 1 sup - sup 2 sup 5 sup 5 No formed in the heavy-ion fusion reactions sup 4 sup 8 Ca+ sup 2 sup 0 sup 6 Pb and sup 4 sup 8 Ca+ sup 2 sup 0 sup 8 Pb. The obtained excitation functions for the reaction products formed after the evaporation of 1-4 neutrons from the corresponding compound No nuclei have been compared with similar data obtained earlier and results of statistical model calculations. (orig.)

  6. SR study of scintillators

    CERN Document Server

    Mikhailin, V V

    2000-01-01

    The technique and the models developed recently in Synchrotron Radiation (SR) Laboratory of Moscow University for the investigation of energy transfer processes in insulators can be applied for a detailed study of scintillator's properties. The experiments with SR in VUV and XUV regions allow to separate various processes and stages of energy transfer and help to indicate the dominating process on each stage. Thus, we can find the way to improve the properties, essential for the particular application of the scintillator: conversion efficiency, decay time, afterglow, radiation hardness, etc. The results of such a study can be used for the testing procedures in scintillator production.

  7. Fe-deficiency in H-deficient post-AGB stars due to n-capture nucleosynthesis

    CERN Document Server

    Herwig, F; Werner, K; Herwig, Falk; Lugaro, Maria; Werner, Klaus

    2002-01-01

    H-deficient post-AGB objects, e.g. PG1159 type star K1-16 and born-again AGB star Sakurai's object, have been reported to be significantly iron-deficient. We find that the iron deficiencies expected due to neutron-capture nucleosynthesis during either the progenitor AGB evolution and/or the neutron burst that occurs as a result of the rapid burning of protons during a post-AGB He-flash are generally in line with observations.

  8. New superconducting oxides in the Bi-Sr-Ca-Cu-0 system: magnetic measurements and structural determination

    Energy Technology Data Exchange (ETDEWEB)

    Giordanengo, B.; Godinho, M.; Lejay, P.; De Rango, P.; Sulpice, A.; Tholence, J.L.; Tournier, R. (Centre National de la Recherche Scientifique, 38 - Grenoble (FR) Centre de Recherches sur les Tres Basses Temperatures, Grenoble, (FR)); Hewat, A.W. (Institut Max Von Laue - Paul Langevin, 38 - Grenoble (FR)); Hewat, E.A. (CEA Centre d' Etudes Nucleaires de Grenoble 38 (FR). Inst. de Recherche Technologique et de Developpement Industriel (IRDI)); Marezio, M. (AT and T Bell Lab., Murray Hill, NJ (US)); Bordet, P.; Capponi, J.J.; Chaillout, C.; Chenavas, J.J.; Hodeau, J.L.; Spieser, A.M.; Tranqui, D. (Centre National de la Recherche Scientifique, 38 - Grenoble (FR) Lab. de Cristallographie (FR))

    1988-12-01

    Detailed neutron diffraction structure analysis of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} is reported. The effects of Pb-substitution on Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} and Bi{sub 2}Sr{sub 2}CuO{sub 6} are discussed, and magnetization measurement results on the 110 K phase in the Bi-Sr-Ca-Cu-O system are given.

  9. VLCAD deficiency

    DEFF Research Database (Denmark)

    Boneh, A; Andresen, B S; Gregersen, N

    2006-01-01

    We diagnosed six newborn babies with very long-chain acyl-CoA dehydrogenase deficiency (VLCADD) through newborn screening in three years in Victoria (prevalence rate: 1:31,500). We identified seven known and two new mutations in our patients (2/6 homozygotes; 4/6 compound heterozygotes). Blood...

  10. Neutron reflectometry

    DEFF Research Database (Denmark)

    Klösgen-Buchkremer, Beate Maria

    2014-01-01

    to hundreds of nanometers. Thickness resolution for flat surfaces is in the range of few Ǻngstrøm, and as a peculiar benefit, the presence and properties of buried interfaces are accessible. Focus here will be on neutron reflectometry, a technique that is unique in applications involving composite organic...... of desired information. In the course, an introduction into the method and an overview on selected instruments at large scale facilities will be presented. Examples will be given that illustrate the potential of the method, mostly based on organic films. Results from the investigation of layered films...... and the detection on nanoscopic roughnesses will be shown. The potential of neutron reflectometry is not only of academic origin. It may turn out to be useful in the design and development of new functional materials even though it will never develop into a standard method to be applied in the product control...

  11. Diffuse neutron scattering from anion-excess strontium chloride

    DEFF Research Database (Denmark)

    Goff, J.P.; Clausen, K.N.; Fåk, B.

    1992-01-01

    The defect structure and diffusional processes have been studied in the anion-excess fluorite (Sr, Y)Cl2.03 by diffuse neutron scattering techniques. Static cuboctahedral clusters found at ambient temperature break up at temperatures below 1050 K, where the anion disorder is highly dynamic...

  12. Spallation Neutron Source (SNS)

    Data.gov (United States)

    Federal Laboratory Consortium — The SNS at Oak Ridge National Laboratory is a next-generation spallation neutron source for neutron scattering that is currently the most powerful neutron source in...

  13. Neutron scattering. Lectures

    Energy Technology Data Exchange (ETDEWEB)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner (eds.)

    2010-07-01

    The following topics are dealt with: Neutron sources, neutron properties and elastic scattering, correlation functions measured by scattering experiments, symmetry of crystals, applications of neutron scattering, polarized-neutron scattering and polarization analysis, structural analysis, magnetic and lattice excitation studied by inelastic neutron scattering, macromolecules and self-assembly, dynamics of macromolecules, correlated electrons in complex transition-metal oxides, surfaces, interfaces, and thin films investigated by neutron reflectometry, nanomagnetism. (HSI)

  14. Neutron Therapy Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Neutron Therapy Facility provides a moderate intensity, broad energy spectrum neutron beam that can be used for short term irradiations for radiobiology (cells)...

  15. SR-71 flyover

    Science.gov (United States)

    1990-01-01

    This clip, running about 14 seconds in length, shows the NASA SR-71 (No. 844) lighting off the afterburners on a low pass over the Dryden Flight Research Center. Two SR-71A aircraft on loan from the U.S. Air Force have been used for high-speed, high-altitude research at the NASA Dryden Flight Research Center, Edwards, California, since 1991. One of them was later returned to the Air Force. A third SR-71 on loan from the Air Force is an SR-71B used for training but not for flight research. Developed for the U.S. Air Force as reconnaissance aircraft more than 30 years ago, SR-71 aircraft are still the world's fastest and highest-flying production aircraft. These aircraft can fly more than 2200 miles per hour (Mach 3+ or more than three times the speed of sound) and at altitudes of over 85,000 feet. This operating environment makes the aircraft excellent platforms to carry out research and experiments in a variety of areas--aerodynamics, propulsion, structures, thermal protection materials, high-speed and high-temperature instrumentation, atmospheric studies, and sonic-boom characterization. Data from the SR-71 high-speed research program may be used to aid designers of future supersonic or hypersonic aircraft and propulsion systems, including a possible high-speed civil transport. The SR-71 program at Dryden has been part of the NASA overall high-speed aeronautical research program, and projects have involved other NASA research centers, other government agencies, universities, and commercial firms. One of the first major experiments to be flown in the NASA SR-71 program was a laser air-data collection system. This system used laser light instead of air pressure to produce airspeed and attitude reference data such as angle of attack and angle of sideslip. These data are normally obtained with small tubes and vanes extending into the air stream, or from tubes with flush openings on the aircraft outer skin. The flights provided information on the presence of

  16. SR-71 flight

    Science.gov (United States)

    1990-01-01

    The movie clip shown here runs about 13 seconds and shows an air-to-air shot of the front of the SR-71 aircraft and a head-on view of it coming in for a landing. Two SR-71A aircraft on loan from the U.S. Air Force have been used for high-speed, high-altitude research at the NASA Dryden Flight Research Center, Edwards, California, since 1991. One of them was later returned to the Air Force. A third SR-71 on loan from the Air Force is an SR-71B used for training but not for flight research. Developed for the U.S. Air Force as reconnaissance aircraft more than 30 years ago, SR-71 aircraft are still the world's fastest and highest-flying production aircraft. These aircraft can fly more than 2200 miles per hour (Mach 3+ or more than three times the speed of sound) and at altitudes of over 85,000 feet. This operating environment makes the aircraft excellent platforms to carry out research and experiments in a variety of areas--aerodynamics, propulsion, structures, thermal protection materials, high-speed and high-temperature instrumentation, atmospheric studies, and sonic-boom characterization. Data from the SR-71 high-speed research program may be used to aid designers of future supersonic or hypersonic aircraft and propulsion systems, including a possible high-speed civil transport. The SR-71 program at Dryden has been part of the NASA overall high-speed aeronautical research program, and projects have involved other NASA research centers, other government agencies, universities, and commercial firms. One of the first major experiments to be flown in the NASA SR-71 program was a laser air-data collection system. This system used laser light instead of air pressure to produce airspeed and attitude reference data such as angle of attack and angle of sideslip. These data are normally obtained with small tubes and vanes extending into the air stream, or from tubes with flush openings on the aircraft outer skin. The flights provided information on the presence of

  17. Increased strontium uptake in trabecular bone of ovariectomized calcium-deficient rats treated with strontium ranelate or strontium chloride.

    Science.gov (United States)

    Pemmer, Bernhard; Hofstaetter, Jochen G; Meirer, Florian; Smolek, Stephan; Wobrauschek, Peter; Simon, Rolf; Fuchs, Robyn K; Allen, Matthew R; Condon, Keith W; Reinwald, Susan; Phipps, Roger J; Burr, David B; Paschalis, Eleftherios P; Klaushofer, Klaus; Streli, Christina; Roschger, Paul

    2011-11-01

    Based on clinical trials showing the efficacy to reduce vertebral and non-vertebral fractures, strontium ranelate (SrR) has been approved in several countries for the treatment of postmenopausal osteoporosis. Hence, it is of special clinical interest to elucidate how the Sr uptake is influenced by dietary Ca deficiency as well as by the formula of Sr administration, SrR versus strontium chloride (SrCl(2)). Three-month-old ovariectomized rats were treated for 90 days with doses of 25 mg kg(-1) d(-1) and 150 mg kg(-1) d(-1) of SrR or SrCl(2) at low (0.1% Ca) or normal (1.19% Ca) Ca diet. Vertebral bone tissue was analysed by confocal synchrotron-radiation-induced micro X-ray fluorescence and by backscattered electron imaging. Principal component analysis and k-means clustering of the acquired elemental maps of Ca and Sr revealed that the newly formed bone exhibited the highest Sr fractions and that low Ca diet increased the Sr uptake by a factor of three to four. Furthermore, Sr uptake in bone of the SrCl(2)-treated animals was generally lower compared with SrR. The study clearly shows that inadequate nutritional calcium intake significantly increases uptake of Sr in serum as well as in trabecular bone matrix. This indicates that nutritional calcium intake as well as serum Ca levels are important regulators of any Sr treatment.

  18. Iron deficiency

    DEFF Research Database (Denmark)

    Schou, Morten; Bosselmann, Helle; Gaborit, Freja

    2015-01-01

    BACKGROUND: Both iron deficiency (ID) and cardiovascular biomarkers are associated with a poor outcome in heart failure (HF). The relationship between different cardiovascular biomarkers and ID is unknown, and the true prevalence of ID in an outpatient HF clinic is probably overlooked. OBJECTIVES.......043). CONCLUSION: ID is frequent in an outpatient HF clinic. ID is not associated with cardiovascular biomarkers after adjustment for traditional confounders. Inflammation, but not neurohormonal activation is associated with ID in systolic HF. Further studies are needed to understand iron metabolism in elderly HF...

  19. Contribution to the spectroscopy of 50 neutron isotones; Contribution a la spectroscopie des isotones a 50 neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Picard, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1969-05-01

    Proton states in the isotones N = 50 have been studied through the reaction ({sup 3}He,d) on {sup 88}Sr, {sup 90}Zr and {sup 92}Mo target nuclei with 18 MeV {sup 3}He projectiles and also neutron hole states using the ({sup 3}He,{alpha}) reaction on the same target. The information thus obtained on independent quasi-particle or hole states completes the set of experimental data required for a microscopic description of the collective properties of the even isotones {sup 88}Sr, {sup 90}Zr and {sup 92}Mo in the framework of BCS(IGE) + RPA theories. The results of this calculation are compared to experimental data and, more particularly, the results of 20 MeV proton inelastic scattering on {sup 88}Sr are analysed using anti-symmetrized DWBA with the microscopic wave functions calculated previously. (author) [French] Les etats de proton des isotones a 50 neutrons sont etudies par la reaction directe ({sup 3}He,d) sur les noyaux {sup 88}Sr, {sup 90}Zr et {sup 92}Mo avec des projectiles {sup 3}He de 18 MeV d'energie; ainsi que les etats de trou de neutron au moyen de la reaction directe ({sup 3}He,{alpha}) sur les memes cibles. L'information ainsi obtenue sur ces etats de trou ou de quasiparticule independante complete l'ensemble des donnees necessaire pour une description microscopique des proprietes collectives des isotones pairs {sup 88}Sr, {sup 90}Zr et {sup 92}Mo dans le cadre des modeles BCS(IGE) + RPA. Les resultats de ce calcul sont compares a l'experience et, en particulier, les resultats de la diffusion inelastique {sup 88}Sr(p,p'){sup 88}Sr{sup *} avec des protons de 20 MeV sont analyses dans un formalisme antisymetrise de la DWBA utilisant les fonctions d'onde microscopiques calculees precedemment. (auteur)

  20. Neutron scattering. Lectures

    Energy Technology Data Exchange (ETDEWEB)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner (eds.)

    2010-07-01

    The following topics are dealt with: Neutron sources, symmetry of crystals, diffraction, nanostructures investigated by small-angle neutron scattering, the structure of macromolecules, spin dependent and magnetic scattering, structural analysis, neutron reflectometry, magnetic nanostructures, inelastic scattering, strongly correlated electrons, dynamics of macromolecules, applications of neutron scattering. (HSI)

  1. Storage phosphors for thermal neutron detection

    CERN Document Server

    Sidorenko, A V; Dorenbos, P; Le Masson, N J M; Rodnyi, P A; Eijk, C W E; Berezovskaya, I V; Dotsenko, V P

    2002-01-01

    The commercial BaFBr:Eu sup 2 sup +centre dot Gd sub 2 O sub 3 image plate (IP) is used nowadays for thermal neutron detection. However, it is rather sensitive to gamma-ray background, which can deteriorate the image quality. We focused our research on the development of new types of storage phosphors with the general formula M sub 2 B sub 5 O sub 9 Br:Ce sup 3 sup + (M=Sr, Ca). Neutron detection is based on the sup 1 sup 0 B(n,alpha) reaction. The advantages of this system are the low Z sub e sub f sub f , and the 40 times higher energy deposition resulting from the neutron capture reaction in comparison with that in the commercial IP. Here we present storage and spectroscopic properties of a series of newly synthesized haloborates. Comparative measurements with commercial IPs were done under neutron and beta irradiation. A satisfying light output of optically stimulated luminescence was achieved upon neutron irradiation.

  2. Neutron Capture Nucleosynthesis

    CERN Document Server

    Kiss, Miklos

    2016-01-01

    Heavy elements (beyond iron) are formed in neutron capture nucleosynthesis processes. We have proposed a simple unified model to investigate the neutron capture nucleosynthesis in arbitrary neutron density environment. We have also investigated what neutron density is required to reproduce the measured abundance of nuclei assuming equilibrium processes. We found both of these that the medium neutron density has a particularly important role at neutron capture nucleosynthesis. About these results most of the nuclei can formed at medium neutron capture density environment e.g. in some kind of AGB stars. Besides these observations our model is capable to use educational purpose.

  3. Nuclear reactor neutron shielding

    Energy Technology Data Exchange (ETDEWEB)

    Speaker, Daniel P; Neeley, Gary W; Inman, James B

    2017-09-12

    A nuclear reactor includes a reactor pressure vessel and a nuclear reactor core comprising fissile material disposed in a lower portion of the reactor pressure vessel. The lower portion of the reactor pressure vessel is disposed in a reactor cavity. An annular neutron stop is located at an elevation above the uppermost elevation of the nuclear reactor core. The annular neutron stop comprises neutron absorbing material filling an annular gap between the reactor pressure vessel and the wall of the reactor cavity. The annular neutron stop may comprise an outer neutron stop ring attached to the wall of the reactor cavity, and an inner neutron stop ring attached to the reactor pressure vessel. An excore instrument guide tube penetrates through the annular neutron stop, and a neutron plug comprising neutron absorbing material is disposed in the tube at the penetration through the neutron stop.

  4. Synthesis and Ionic Conduction of Cation-deficient Apatite La9.33-2x/3 MxSi6O26 Doped with Mg, Ca, Sr%掺杂的阳离子缺陷型磷灰石La9.33-2x/3MxSi6O26(M=Mg,Sr,Ca)的合成及离子导电特性

    Institute of Scientific and Technical Information of China (English)

    袁文辉; 顾亚萍; 李莉

    2008-01-01

    Apatite-type lanthanum silicate with special conduction mechanism via interstitial oxygen has attracted considerable interest in recent years. In this work, pure powder of La9.33-2x/3 MxSi6O26 (M=Mg, Ca, Sr) is prepared by the sol-gel method with sintering at 1000℃. The powder is characterized by X-ray diffraction (XRD) and scanning electron micrograph (SEM). The apatite can be obtained at relatively low temperature as compared to the conventional solid-state reaction method. The measurements of conductivity of a series of doped samples La9.33-2x/3 MxSi6O26 (M=Ca, Mg, Sr) indicate that the type of dopant and the amount have a significant effect on the conductivity. The greatest decrease in conductivity is observed for Mg doping, following the Ca and the Sr doped apatites. The effect is ultimately attributed to the amount of oxygen interstitials, which is affected by the crystal lattice distortion arising from cation vacancies.

  5. Weapons Neutron Research Facility (WNR)

    Data.gov (United States)

    Federal Laboratory Consortium — The Weapons Neutron Research Facility (WNR) provides neutron and proton beams for basic, applied, and defense-related research. Neutron beams with energies ranging...

  6. Low-energy Coulomb excitation of Sr,9896 beams

    Science.gov (United States)

    Clément, E.; Zielińska, M.; Péru, S.; Goutte, H.; Hilaire, S.; Görgen, A.; Korten, W.; Doherty, D. T.; Bastin, B.; Bauer, C.; Blazhev, A.; Bree, N.; Bruyneel, B.; Butler, P. A.; Butterworth, J.; Cederkäll, J.; Delahaye, P.; Dijon, A.; Ekström, A.; Fitzpatrick, C.; Fransen, C.; Georgiev, G.; Gernhäuser, R.; Hess, H.; Iwanicki, J.; Jenkins, D. G.; Larsen, A. C.; Ljungvall, J.; Lutter, R.; Marley, P.; Moschner, K.; Napiorkowski, P. J.; Pakarinen, J.; Petts, A.; Reiter, P.; Renstrøm, T.; Seidlitz, M.; Siebeck, B.; Siem, S.; Sotty, C.; Srebrny, J.; Stefanescu, I.; Tveten, G. M.; Van de Walle, J.; Vermeulen, M.; Voulot, D.; Warr, N.; Wenander, F.; Wiens, A.; De Witte, H.; Wrzosek-Lipska, K.

    2016-11-01

    The structure of neutron-rich Sr,9896 nuclei was investigated by low-energy safe Coulomb excitation of radioactive beams at the REX-ISOLDE facility, CERN, with the MINIBALL spectrometer. A rich set of transitional and diagonal E 2 matrix elements, including those for non-yrast structures, has been extracted from the differential Coulomb-excitation cross sections. The results support the scenario of a shape transition at N =60 , giving rise to the coexistence of a highly deformed prolate and a spherical configuration in 98Sr, and are compared to predictions from several theoretical calculations. The experimental data suggest a significant contribution of the triaxal degree of freedom in the ground state of both isotopes. In addition, experimental information on low-lying states in 98Rb has been obtained.

  7. Structural and magnetic properties of the 5$d^2$ double perovskites Sr$_2 B$ReO$_6$ ($B$ $=$ Y, In)

    OpenAIRE

    Aczel, A. A.; Zhao, Z.; Calder, S.; Adroja, D T; Baker, P. J.; Yan, J. -Q.

    2016-01-01

    We have performed magnetic susceptibility, heat capacity, neutron powder diffraction, and muon spin relaxation experiments to investigate the magnetic ground states of the 5$d^2$ double perovskites Sr$_2$YReO$_6$ and Sr$_2$InReO$_6$. We find that Sr$_2$YReO$_6$ is a spin glass, while Sr$_2$InReO$_6$ hosts a non-magnetic singlet state. By making detailed comparisons with other 5$d^2$ double perovskites, we argue that a delicate interplay between spin-orbit coupling, non-cubic crystal fields, a...

  8. Vitamin Deficiency Anemia

    Science.gov (United States)

    ... are unique to specific vitamin deficiencies. Folate-deficiency anemia risk factors include: Undergoing hemodialysis for kidney failure. ... the metabolism of folate. Vitamin B-12 deficiency anemia risk factors include: Lack of intrinsic factor. Most ...

  9. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... at highest risk for iron-deficiency anemia. Outlook Doctors usually can successfully treat iron-deficiency anemia. Treatment ... poor skin tone, dizziness, and depression. After her doctor diagnosed her with iron-deficiency anemia, Susan got ...

  10. Superheated drop neutron spectrometer

    CERN Document Server

    Das, M; Roy, B; Roy, S C; Das, Mala

    2000-01-01

    Superheated drops are known to detect neutrons through the nucleation caused by the recoil nuclei produced by the interactions of neutrons with the atoms constituting the superheated liquid molecule. A novel method of finding the neutron energy from the temperature dependence response of SDD has been developed. From the equivalence between the dependence of threshold energy for nucleation on temperature of SDD and the dependence of dE/dx of the recoil ions with the energy of the neutron, a new method of finding the neutron energy spectrum of a polychromatic as well as monochromatic neutron source has been developed.

  11. Neutron streak camera

    Science.gov (United States)

    Wang, Ching L.

    1983-09-13

    Apparatus for improved sensitivity and time resolution of a neutron measurement. The detector is provided with an electrode assembly having a neutron sensitive cathode which emits relatively low energy secondary electrons. The neutron sensitive cathode has a large surface area which provides increased sensitivity by intercepting a greater number of neutrons. The cathode is also curved to compensate for differences in transit time of the neutrons emanating from the point source. The slower speeds of the secondary electrons emitted from a certain portion of the cathode are matched to the transit times of the neutrons impinging thereupon.

  12. Considerations in the design of an improved transportable neutron spectrometer

    CERN Document Server

    Williams, A M; Brushwood, J M; Beeley, P A

    2002-01-01

    The Transportable Neutron Spectrometer (TNS) has been used by the Ministry of Defence for over 15 years to characterise neutron fields in workplace environments and provide local correction factors for both area and personal dosimeters. In light of advances in neutron spectrometry, a programme to evaluate and improve TNS has been initiated. This paper describes TNS, presents its operation in known radioisotope fields and in a reactor environment. Deficiencies in the operation of the instrument are highlighted, together with proposals for updating the response functions and spectrum unfolding methodologies.

  13. Ternary Particles with Extreme N/z Ratios from Neutron-Induced Fission

    Science.gov (United States)

    Köster, Ulli; Faust, Herbert; Friedrichs, Thomas; Oberstedt, Stephan; Fioni, Gabriele; Groß, Martin; Ahmad, Irshad

    The following sections are included: * Introduction * Ternary fission models * Common parameterization * Experimental results * Yields of neutron-deficient nuclei * 3He * 6Li, 7Be and 10B * 15O * Yield of very neutron-rich nuclei * Suppression of halo nuclei? * Acknowledgements * References

  14. Neutron anatomy

    Energy Technology Data Exchange (ETDEWEB)

    Bacon, G.E. [Univ. of Sheffield (United Kingdom)

    1994-12-31

    The familiar extremes of crystalline material are single-crystals and random powders. In between these two extremes are polycrystalline aggregates, not randomly arranged but possessing some preferred orientation and this is the form taken by constructional materials, be they steel girders or the bones of a human or animal skeleton. The details of the preferred orientation determine the ability of the material to withstand stress in any direction. In the case of bone the crucial factor is the orientation of the c-axes of the mineral content - the crystals of the hexagonal hydroxyapatite - and this can readily be determined by neutron diffraction. In particular it can be measured over the volume of a piece of bone, utilizing distances ranging from 1mm to 10mm. The major practical problem is to avoid the intense incoherent scattering from the hydrogen in the accompanying collagen; this can best be achieved by heat-treatment and it is demonstrated that this does not affect the underlying apatite. These studies of bone give leading anatomical information on the life and activities of humans and animals - including, for example, the life history of the human femur, the locomotion of sheep, the fracture of the legs of racehorses and the life-styles of Neolithic tribes. We conclude that the material is placed economically in the bone to withstand the expected stresses of life and the environment. The experimental results are presented in terms of the magnitude of the 0002 apatite reflection. It so happens that for a random powder the 0002, 1121 reflections, which are neighboring lines in the powder pattern, are approximately equal in intensity. The latter reflection, being of manifold multiplicity, is scarcely affected by preferred orientation so that the numerical value of the 0002/1121 ratio serves quite accurately as a quantitative measure of the degree of orientation of the c-axes in any chosen direction for a sample of bone.

  15. Progress report on neutron scattering at JAERI

    Energy Technology Data Exchange (ETDEWEB)

    Morii, Yukio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2000-10-01

    Progress in neutron scattering experiments at Japan Atomic Energy Research Institute for the year 1997-1998 is reported in brief. The superconducting gap was discovered in the spin excitation spectra of a heavy fermion superconductor UPd{sub 2}Al{sub 3}, which proved the superconductivity of this compound to be due to magnetic origin. The magnetic and superconducting order parameter was found in UPd{sub 2}Al{sub 3}, UNi{sub 2}Al{sub 3}, UPt{sub 3} and URu{sub 2}Si{sub 2}. It was concluded from this result that the coupling of the order parameter would be a characteristic property in heavy fermion superconductors. The correlation between strong magnetic interaction and the superconducting transition under high pressure was indicated from spin excitation in the strongly correlated electron system of a ladder material (Sr,Ca){sub 14}Cu{sub 24}O{sub 41}. The magnetic flux structure in a Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} superconductor was examined by SANS (small angle neutron scattering) to observe the decomposition of the flux lines. A liquid-He-free dilution refrigerator was developed for neutron scattering experiments at ultralow temperature. The coherent scattering length of the {sup 69}Ga and {sup 71}Ga was evaluated by use of the apparatus for precise neutron optics. The structure of hen egg-white Lysozyne was investigated in detail. Detailed research report for the year 1997-1998 was published in the JAERI-Review 99-003. (Y. Kazumata)

  16. Neutron bound beta-decay: BOB

    Energy Technology Data Exchange (ETDEWEB)

    McAndrew, Josephine, E-mail: j.mcandrew@tum.de; Paul, Stephan; Emmerich, Ralf [TUM, Physik-Department (Germany); Engels, Ralf [Forschungszentrum Juelich, Institut Fuer Kernphysik (Germany); Fierlinger, Peter [TUM, Excellence Cluster Universe (Germany); Gabriel, Mirko; Gutsmiedl, Erwin; Mellenthin, Johannes; Schoen, Johannes; Schott, Wolfgang; Ulrich, Andreas; Grueenauer, Florian [TUM, Physik-Department (Germany); Roehrmoser, Anton [FRMII (Germany)

    2012-05-15

    An experiment to observe the bound beta-decay (BOB) of the free neutron into a hydrogen atom and an electron anti-neutrino is described. The hyperfine spin state population of the monoenergetic hydrogen atom yields the neutrino left-handedness or possible right-handed admixture as well as possible small scalar and tensor contributions to the weak force. The BOB H(2s) hyperfine states can be separated with a Lamb-Shift Spin Filter. These monoenergetic H(2s) atoms are ionised into H{sup -} by charge exchanging within an argon cell. These ions are then separated using an adaptation of a MAC-E Filter. A first experiment is proposed at the FRMII high thermal-neutron flux beam reactor SR6 through-going beam tube, where we will seek to observe this rare neutron decay-mode for the first time and determine the branching ratio. After successful completion, the hyperfine spin state population will be determined, possibly at the ILL high-flux beam reactor through-going beam tube H6-H7, where the thermal neutron flux is a factor of four larger.

  17. Imaging with Scattered Neutrons

    OpenAIRE

    Ballhausen, H.; Abele, H.; Gaehler, R.; Trapp, M.; Van Overberghe, A.

    2006-01-01

    We describe a novel experimental technique for neutron imaging with scattered neutrons. These scattered neutrons are of interest for condensed matter physics, because they permit to reveal the local distribution of incoherent and coherent scattering within a sample. In contrast to standard attenuation based imaging, scattered neutron imaging distinguishes between the scattering cross section and the total attenuation cross section including absorption. First successful low-noise millimeter-re...

  18. Intense fusion neutron sources

    Science.gov (United States)

    Kuteev, B. V.; Goncharov, P. R.; Sergeev, V. Yu.; Khripunov, V. I.

    2010-04-01

    The review describes physical principles underlying efficient production of free neutrons, up-to-date possibilities and prospects of creating fission and fusion neutron sources with intensities of 1015-1021 neutrons/s, and schemes of production and application of neutrons in fusion-fission hybrid systems. The physical processes and parameters of high-temperature plasmas are considered at which optimal conditions for producing the largest number of fusion neutrons in systems with magnetic and inertial plasma confinement are achieved. The proposed plasma methods for neutron production are compared with other methods based on fusion reactions in nonplasma media, fission reactions, spallation, and muon catalysis. At present, intense neutron fluxes are mainly used in nanotechnology, biotechnology, material science, and military and fundamental research. In the near future (10-20 years), it will be possible to apply high-power neutron sources in fusion-fission hybrid systems for producing hydrogen, electric power, and technological heat, as well as for manufacturing synthetic nuclear fuel and closing the nuclear fuel cycle. Neutron sources with intensities approaching 1020 neutrons/s may radically change the structure of power industry and considerably influence the fundamental and applied science and innovation technologies. Along with utilizing the energy produced in fusion reactions, the achievement of such high neutron intensities may stimulate wide application of subcritical fast nuclear reactors controlled by neutron sources. Superpower neutron sources will allow one to solve many problems of neutron diagnostics, monitor nano-and biological objects, and carry out radiation testing and modification of volumetric properties of materials at the industrial level. Such sources will considerably (up to 100 times) improve the accuracy of neutron physics experiments and will provide a better understanding of the structure of matter, including that of the neutron itself.

  19. Experimental demonstration of a compact epithermal neutron source based on a high power laser

    Science.gov (United States)

    Mirfayzi, S. R.; Alejo, A.; Ahmed, H.; Raspino, D.; Ansell, S.; Wilson, L. A.; Armstrong, C.; Butler, N. M. H.; Clarke, R. J.; Higginson, A.; Kelleher, J.; Murphy, C. D.; Notley, M.; Rusby, D. R.; Schooneveld, E.; Borghesi, M.; McKenna, P.; Rhodes, N. J.; Neely, D.; Brenner, C. M.; Kar, S.

    2017-07-01

    Epithermal neutrons from pulsed-spallation sources have revolutionised neutron science allowing scientists to acquire new insight into the structure and properties of matter. Here, we demonstrate that laser driven fast (˜MeV) neutrons can be efficiently moderated to epithermal energies with intrinsically short burst durations. In a proof-of-principle experiment using a 100 TW laser, a significant epithermal neutron flux of the order of 105 n/sr/pulse in the energy range of 0.5-300 eV was measured, produced by a compact moderator deployed downstream of the laser-driven fast neutron source. The moderator used in the campaign was specifically designed, by the help of MCNPX simulations, for an efficient and directional moderation of the fast neutron spectrum produced by a laser driven source.

  20. International Neutron Radiography Newsletter

    DEFF Research Database (Denmark)

    Domanus, Joseph Czeslaw

    1986-01-01

    At the First World Conference on Neutron Radiography i t was decided to continue the "Neutron Radiography Newsletter", published previously by J.P. Barton, as the "International Neutron Radiography Newsletter" (INRNL), with J.C. Doraanus as editor. The British Journal of Non-Destructive Testing...

  1. Advanced neutron absorber materials

    Science.gov (United States)

    Branagan, Daniel J.; Smolik, Galen R.

    2000-01-01

    A neutron absorbing material and method utilizing rare earth elements such as gadolinium, europium and samarium to form metallic glasses and/or noble base nano/microcrystalline materials, the neutron absorbing material having a combination of superior neutron capture cross sections coupled with enhanced resistance to corrosion, oxidation and leaching.

  2. Prototype Neutron Energy Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Stephen Mitchell, Sanjoy Mukhopadhyay, Richard Maurer, Ronald Wolff

    2010-06-16

    The project goals are: (1) Use three to five pressurized helium tubes with varying polyethylene moderators to build a neutron energy spectrometer that is most sensitive to the incident neutron energy of interest. Neutron energies that are of particular interest are those from the fission neutrons (typically around 1-2 MeV); (2) Neutron Source Identification - Use the neutron energy 'selectivity' property as a tool to discriminate against other competing processes by which neutrons are generated (viz. Cosmic ray induced neutron production [ship effect], [a, n] reactions); (3) Determine the efficiency as a function of neutron energy (response function) of each of the detectors, and thereby obtain the composite neutron energy spectrum from the detector count rates; and (4) Far-field data characterization and effectively discerning shielded fission source. Summary of the presentation is: (1) A light weight simple form factor compact neutron energy spectrometer ready to be used in maritime missions has been built; (2) Under laboratory conditions, individual Single Neutron Source Identification is possible within 30 minutes. (3) Sources belonging to the same type of origin viz., (a, n), fission, cosmic cluster in the same place in the 2-D plot shown; and (4) Isotopes belonging to the same source origin like Cm-Be, Am-Be (a, n) or Pu-239, U-235 (fission) do have some overlap in the 2-D plot.

  3. The low Sr/Ba ratio on some extremely metal-poor stars

    CERN Document Server

    Spite, M; Bonifacio, P; Caffau, E; François, P; Sbordone, L

    2014-01-01

    It has been noted that, in classical extremely metal-poor (EMP) stars, the abundance ratio of Sr and Ba, is always higher than [Sr/Ba] = -0.5, the value of the solar r-only process; however, a handful of EMP stars have recently been found with a very low Sr/Ba ratio. We try to understand the origin of this anomaly by comparing the abundance pattern of the elements in these stars and in the classical EMP stars. Four stars with very low Sr/Ba ratios were observed and analyzed within LTE approximation through 1D (hydrostatic) model atmosphere, providing homogeneous abundances of nine neutron-capture elements. In CS 22950-173, the only turnoff star of the sample, the Sr/Ba ratio is, in fact, found to be higher than the r-only solar ratio, so the star is discarded. The remaining stars (CS 29493-090, CS 30322-023, HE 305-4520) are cool evolved giants. They do not present a clear carbon enrichment. The abundance patterns of the neutron-capture elements in the three stars are strikingly similar to a theoretical s-pro...

  4. Neutron scattering. Experiment manuals

    Energy Technology Data Exchange (ETDEWEB)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner (eds.)

    2010-07-01

    The following topics are dealt with: The thermal triple axis spectrometer PUMA, the high-resolution powder diffractometer SPODI, the hot single-crystal diffractometer HEiDi for structure analysis with neutrons, the backscattering spectrometer SPHERES, neutron polarization analysis with tht time-of-flight spectrometer DNS, the neutron spin-echo spectrometer J-NSE, small-angle neutron scattering with the KWS-1 and KWS-2 diffractometers, the very-small-angle neutron scattering diffractrometer with focusing mirror KWS-3, the resonance spin-echo spectrometer RESEDA, the reflectometer TREFF, the time-of-flight spectrometer TOFTOF. (HSI)

  5. Grazing Incidence Neutron Optics

    Science.gov (United States)

    Gubarev, Mikhail V. (Inventor); Ramsey, Brian D. (Inventor); Engelhaupt, Darell E. (Inventor)

    2013-01-01

    Neutron optics based on the two-reflection geometries are capable of controlling beams of long wavelength neutrons with low angular divergence. The preferred mirror fabrication technique is a replication process with electroform nickel replication process being preferable. In the preliminary demonstration test an electroform nickel optics gave the neutron current density gain at the focal spot of the mirror at least 8 for neutron wavelengths in the range from 6 to 20.ANG.. The replication techniques can be also be used to fabricate neutron beam controlling guides.

  6. Neutron scatter camera

    Science.gov (United States)

    Mascarenhas, Nicholas; Marleau, Peter; Brennan, James S.; Krenz, Kevin D.

    2010-06-22

    An instrument that will directly image the fast fission neutrons from a special nuclear material source has been described. This instrument can improve the signal to background compared to non imaging neutron detection techniques by a factor given by ratio of the angular resolution window to 4.pi.. In addition to being a neutron imager, this instrument will also be an excellent neutron spectrometer, and will be able to differentiate between different types of neutron sources (e.g. fission, alpha-n, cosmic ray, and D-D or D-T fusion). Moreover, the instrument is able to pinpoint the source location.

  7. Carnitine Deficiency and Pregnancy

    OpenAIRE

    Anouk de Bruyn; Yves Jacquemyn; Kristof Kinget; François Eyskens

    2015-01-01

    We present two cases of carnitine deficiency in pregnancy. In our first case, systematic screening revealed L-carnitine deficiency in the first born of an asymptomatic mother. In the course of her second pregnancy, maternal carnitine levels showed a deficiency as well. In a second case, a mother known with carnitine deficiency under supplementation was followed throughout her pregnancy. Both pregnancies had an uneventful outcome. Because carnitine deficiency can have serious complications, su...

  8. Advances in neutron tomography

    Indian Academy of Sciences (India)

    W Treimer

    2008-11-01

    In the last decade neutron radiography (NR) and tomography (NCT) have experienced a number of improvements, due to the well-known properties of neutrons interacting with matter, i.e. the low attenuation by many materials, the strong attenuation by hydrogenous constituent in samples, the wavelength-dependent attenuation in the neighbourhood of Bragg edges and due to better 2D neutron detectors. So NR and NCT were improved by sophisticated techniques that are based on the attenuation of neutrons or on phase changes of the associated neutron waves if they pass through structured materials. Up to now the interaction of the neutron spin with magnetic fields in samples has not been applied to imaging techniques despite the fact that it was proposed many years ago. About ten years ago neutron depolarization as imaging signal for neutron radiography or tomography was demonstrated and in principle it works. Now one can present much improved test experiments using polarized neutrons for radiographic imaging. For this purpose the CONRAD instrument of the HMI was equipped with polarizing and analysing benders very similar to conventional scattering experiments using polarized neutrons. Magnetic fields in different coils and in samples (superconductors) at low temperatures could be visualized. In this lecture a summary about standard signals (attenuation) and the more `sophisticated' imaging signals as refraction, small angle scattering and polarized neutrons will be given.

  9. Neutronic Reactor Shield

    Science.gov (United States)

    Fermi, Enrico; Zinn, Walter H.

    The argument of the present Patent is a radiation shield suitable for protection of personnel from both gamma rays and neutrons. Such a shield from dangerous radiations is achieved to the best by the combined action of a neutron slowing material (a moderator) and a neutron absorbing material. Hydrogen is particularly effective for this shield since it is a good absorber of slow neutrons and a good moderator of fast neutrons. The neutrons slowed down by hydrogen may, then, be absorbed by other materials such as boron, cadmium, gadolinium, samarium or steel. Steel is particularly convenient for the purpose, given its effectiveness in absorbing also the gamma rays from the reactor (both primary gamma rays and secondary ones produced by the moderation of neutrons). In particular, in the present Patent a shield is described, made of alternate layers of steel and Masonite (an hydrolized ligno-cellulose material). The object of the present Patent is not discussed in any other published paper.

  10. First observation of nonyrast levels in Zr-103 and level systematics of N=63 Sr, Zr, and Mo isotones

    NARCIS (Netherlands)

    Lhersonneau, G; Dendooven, P; Honkanen, A; Huhta, M; Oinonen, M; Penttila, H; Aysto, J; Kurpeta, J; Persson, B.L.; Popov, A

    1996-01-01

    The beta decay of the very-neutron-rich nucleus Y-103 has been studied at the isotope separator IGISOL, allowing for the first time the observation of nonyrast levels in its daughter Zr-103(40)63. The level structure is similar to that of its isotones Sr-101 and Mo-105, suggesting a targe ground-sta

  11. Study of dependence of quasi-particle alignment on proton and neutron numbers in A = 80 region through g-factor measurements

    Science.gov (United States)

    Daqing, Yuan; Ping, Fan; Yongnan, Zheng; Yi, Zuo; Dongmei, Zhou; Qiaoli, Zhang; Xiaoguang, Wu; Guangsheng, Li; Lihua, Zhu; Guoji, Xu; Qiwen, Fan; Xizhen, Zhang; Matsuta, K.; Fukuda, M.; Mihara, M.; Minamisono, T.; Shengyun, Zhu

    2010-06-01

    Dependence of quasi-particle alignment on proton and neutron numbers has been studied in A = 80 mass region through g-factor measurements by using TMF-IMPAD. The experimental results show that for the nuclides 84Zr, 85Zr and 86Zr with Z = 40 the proton alignment is followed by the neutron alignment in 84Zr and 85Zr, while the neutron alignment is followed by the proton alignment in 86Zr, and for the nuclides 82Sr, 83Y, 84Zr and 85Nb with N = 44 the proton aligns only in 82Sr, the proton alignment occurs first that is followed by the neutron alignment in 83Y and 84Zr and the neutron alignment is followed by the proton alignment in 85Nb. Proton and/or neutron alignments lead to different patterns of the g-factor variation with spin.

  12. Study of vacancies and extended defects in SrTiO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Zschornak, M. [Institute of Ion Beam Physics and Materials Research, FZ Dresden-Rossendorf, 01328 Dresden (Germany); Institute of Structural Physics, TU-Dresden, 01062 Dresden (Germany); Gutmann, E.; Stoecker, H.; Shakhverdova, I.; Weissbach, T.; Meyer, D.C. [Institute of Structural Physics, TU-Dresden, 01062 Dresden (Germany); Gemming, S. [Institute of Ion Beam Physics and Materials Research, FZ Dresden-Rossendorf, 01328 Dresden (Germany)

    2009-07-01

    SrTiO{sub 3} is an oxide crystallizing with cubic perovskite-type of structure that exhibits a high tunability of dielectric, electric, mechanical and optical properties by means of defects. Apart from dopants, also intrinsic oxygen vacancies or ordered stacking faults, e.g. Ruddlesden-Popper (RP) phases SrO(SrTiO{sub 3}){sub n}, may influence these properties. We have investigated the structural stability, electronic properties and surface energies of such RP phases up to n=5 by means of density-functional theory. Further, we have theoretically verified an anisotropic reversible elastic softening along an O-deficient left angle 100 right angle direction recently found in nano-indentation of SrTiO{sub 3} under influence of an electric field.

  13. Instrumental neutron activation analysis of some ayurvedic medicines: Pt. 1

    Energy Technology Data Exchange (ETDEWEB)

    Rajurkar, N.S.; Vinchurkar, M.S. (Poona Univ., Pune (India). Dept. of Chemistry)

    1992-12-01

    Several medicines have been manufactured and prescribed to overcome mineral deficiencies in the human body. Such medicines are mixtures of several components. The present work is undertaken to analyze various Ayurvedic medicines, mainly of herbal origin and used for different purposes, for their elemental contents, by neutron activation analysis. (author).

  14. Spin Measurements of n+Sr-87 for Level Density Studies

    CERN Document Server

    Gunsing, F; Mathelie, M; Valenta, S; Bečvář, F; Rusev, G; Tonchev, A P; Mitchell, G; Baramsai, B; Altstadt, S; Andrzejewski, J; Audouin, L; Barbagallo, M; Bécares, V; Belloni, F; Berthoumieux, E; Billowes, J; Boccone, V; Bosnar, D; Brugger, M; Calviani, M; Calviño, F; Cano-Ott, D; Carrapiço, C; Cerutti, F; Chiaveri, E; Chin, M; Colonna, N; Cortés, G; Cortés-Giraldo, M A; Diakaki, M; Domingo-Pardo, C; Duran, I; Dressler, R; Eleftheriadis, C; Ferrari, A; Ganesan, S; García, A R; Giubrone, G; Gonçalves, I.F.; González-Romero, E; Griesmayer, E; Guerrero, C; Hernández-Prieto, A; Jenkins, D G; Jericha, E; Kadi, Y; Käppeler, F; Karadimos, D; Koehler, P; Kokkoris, M; Krtička, M; Kroll, J; Lampoudis, C; Langer, C; Leal-Cidoncha, E; Lederer, C; Leeb, H; Leong, L S; Losito, R; Manousos, A; Marganiec, J; Martínez, T; Massimi, C; Mastinu, P F; Mastromarco, M; Mendoza, E; Mengoni, A; Milazzo, P M; Mingrone, F; Mirea, M; Mondalaers, W; Paradela, C; Pavlik, A; Perkowski, J; Plompen, A; Praena, J; Quesada, J M; Rauscher, T; Reifarth, R; Riego, A; Robles, M S; Rubbia, C; Sabaté-Gilarte, M; Sarmento, R; Saxena, A; Schillebeeckx, P; Schmidt, S; Schumann, D; Tagliente, G; Tain, J L; Tarrío, D; Tassan-Got, L; Tsinganis, A; Vannini, G; Variale, V; Vaz, P; Ventura, A; Vermeulen, M J; Vlachoudis, V; Vlastou, R; Wallner, A; Ware, T; Weigand, M; Weiß, C; Wright, T; Žugec, P

    2014-01-01

    We have used the 4 pi BaF2 gamma-ray detector array at the n\\_TOF neutron time-of-flight facility at CERN for an experiment in order to determine the spins of resonances of n+Sr-87 by measuring the gamma-ray spectra and multiplicity distributions. The first results are presented here. We have assigned the orbital momentum l to all evaluated resonances on the basis of their neutron widths. Further we have assigned the spin J to 16 s-wave resonances on based the population of low-lying levels.

  15. High-Spin States in ~(86)Sr

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The previous works for high spins states of 86Sr were very scarce. In the past, the spin of highest level of 86Sr was 13 found by the reaction 84Kr(α, 2nγ)86Sr in 28 MeV. The current work updates the level scheme of 86Sr to get more information about high spin states in 86Sr.

  16. Oxygen transport in epitaxial SrTiO3/SrTi1 − xFexO3 multilayer stacks

    OpenAIRE

    Schulz, Michal; Orland, Timna; Mehlmann, Alexander; Rothschild, Avner; Fritze, Holger

    2017-01-01

    Nano-ionic materials made of strontium titanate (SrTiO3, STO) and solid solutions of strontium ferrite in STO (SrTi1 − xFexO3, STF) are grown on single crystalline STO substrates and characterized. Since STF exhibits an oxygen deficiency and, simultaneously, enables oxygen interstitial defects, a space charge area close to the STO | STF interface is present. Oxygen tracer diffusion experiments and impedance spectroscopy at temperatures from 500 to 700 °C and at oxygen partia...

  17. Neutron imaging with the short-pulse laser driven neutron source at the Trident laser facility

    Science.gov (United States)

    Guler, N.; Volegov, P.; Favalli, A.; Merrill, F. E.; Falk, K.; Jung, D.; Tybo, J. L.; Wilde, C. H.; Croft, S.; Danly, C.; Deppert, O.; Devlin, M.; Fernandez, J.; Gautier, D. C.; Geissel, M.; Haight, R.; Hamilton, C. E.; Hegelich, B. M.; Henzlova, D.; Johnson, R. P.; Schaumann, G.; Schoenberg, K.; Schollmeier, M.; Shimada, T.; Swinhoe, M. T.; Taddeucci, T.; Wender, S. A.; Wurden, G. A.; Roth, M.

    2016-10-01

    Emerging approaches to short-pulse laser-driven neutron production offer a possible gateway to compact, low cost, and intense broad spectrum sources for a wide variety of applications. They are based on energetic ions, driven by an intense short-pulse laser, interacting with a converter material to produce neutrons via breakup and nuclear reactions. Recent experiments performed with the high-contrast laser at the Trident laser facility of Los Alamos National Laboratory have demonstrated a laser-driven ion acceleration mechanism operating in the regime of relativistic transparency, featuring a volumetric laser-plasma interaction. This mechanism is distinct from previously studied ones that accelerate ions at the laser-target surface. The Trident experiments produced an intense beam of deuterons with an energy distribution extending above 100 MeV. This deuteron beam, when directed at a beryllium converter, produces a forward-directed neutron beam with ˜5 × 109 n/sr, in a single laser shot, primarily due to deuteron breakup. The neutron beam has a pulse duration on the order of a few nanoseconds with an energy distribution extending from a few hundreds of keV to almost 80 MeV. For the experiments on neutron-source spot-size measurements, our gated neutron imager was setup to select neutrons in the energy range of 2.5-35 MeV. The spot size of neutron emission at the converter was measured by two different imaging techniques, using a knife-edge and a penumbral aperture, in two different experimental campaigns. The neutron-source spot size is measured ˜1 mm for both experiments. The measurements and analysis reported here give a spatial characterization for this type of neutron source for the first time. In addition, the forward modeling performed provides an empirical estimate of the spatial characteristics of the deuteron ion-beam. These experimental observations, taken together, provide essential yet unique data to benchmark and verify theoretical work into the

  18. Coral Sr-U Thermometry

    Science.gov (United States)

    DeCarlo, T. M.; Gaetani, G. A.; Cohen, A. L.; Foster, G. L.; Alpert, A.; Stewart, J.

    2016-12-01

    Coral skeletons archive the past two millennia of climate variability in the oceans with unrivaled temporal resolution. However, extracting accurate temperature information from coral skeletons is confounded by "vital effects", which often override the temperature dependence of geochemical proxies. Here, we present a new approach to coral paleothermometry based on results of abiogenic precipitation experiments interpreted within a framework provided by a quantitative model of the coral biomineralization process. We conducted laboratory experiments to test the temperature and carbonate chemistry controls on abiogenic partitioning of Sr/Ca and U/Ca between aragonite and seawater, and we modeled the sensitivity of skeletal composition to processes occurring at the site of calcification. The model predicts that temperature can be accurately reconstructed from coral skeleton by combining Sr/Ca and U/Ca ratios into a new proxy, Sr-U. We tested the model predictions with measured Sr/Ca and U/Ca ratios of fourteen Porites sp. corals collected from the tropical Pacific Ocean and the Red Sea, with a subset also analyzed using the boron isotope (δ11B) pH proxy. Observed relationships among Sr/Ca, U/Ca, and δ11B agree with model predictions, indicating that the model accounts for the key features of the coral biomineralization process. We calibrated Sr-U to instrumental temperature records and found that it captures 93% of mean annual variability (26-30 °C) and predicts temperature within 0.5 °C (1 σ). Conversely, Sr/Ca alone has an error of prediction of 1 °C and often diverges from observed temperature by 3 °C or more. Many of the problems afflicting Sr/Ca - including offsets among neighboring corals and decouplings from temperature during coral stress events - are reconciled by Sr-U. By accounting for the influence of the coral biomineralization process, the Sr-U thermometer may offer significantly improved reliability for reconstructing ocean temperatures from coral

  19. Electronic properties of defects in SrTiO{sub 3} - theory and experiments

    Energy Technology Data Exchange (ETDEWEB)

    Weissbach, Torsten; Zschornak, Matthias; Gutmann, Emanuel; Stoecker, Hartmut; Leisegang, Tilmann; Meyer, Dirk C. [Institut fuer Strukturphysik, TU Dresden (Germany); Riedl, Thomas; Gemming, Thomas [Leibniz-Institut fuer Festkoerper-und Werkstoffforschung (IFW), Dresden (Germany); Gemming, Sibylle [Forschungszentrum, Dresden-Rossendorf (Germany)

    2009-07-01

    SrTiO{sub 3} is a commercially available wafer material e.g. for the integration of oxide superconductors or microwave filter applications. The electric properties of SrTiO{sub 3} are routinely modified by doping with additional elements such as Nb. A targeted defect engineering may, however, achieve similar or superior results, while remaining in the ternary system (Sr,Ti,O), i.e. without the need for extrinsic doping. Material characterization methods able to distinguish such defects in particular are needed. In the present study we combine all-electron first-principles calculations with electron energy loss and X-ray absorption spectroscopy to study the electronic properties of SrTiO{sub 3}-related oxygen deficient compounds. In particular, such changes of the SrTiO{sub 3} core-level spectra are studied, which occur if O vacancies accumulate in SrTiO{sub (3-{delta})}, or if excess SrO(001) planes are inserted to form Ruddlesden-Popper-type compounds.

  20. Status of spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Oyama, Yukio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-03-01

    Existing and planned facilities using proton accelerator driven spallation neutron source are reviewed. These include new project of neutron science proposed from Japan Atomic Energy Research Institute. The present status of facility requirement and accelerator technology leads us to new era of neutron science such as neutron scattering research and nuclear transmutation study using very intense neutron source. (author)

  1. Progress in neutron activation analysis for uranium

    Institute of Scientific and Technical Information of China (English)

    杜鸿善; 李贵群; 董桂芝; 李俊兰; K.H.Chiu; C.M.Wai

    1996-01-01

    A new type of extractant, sym-dibenzo-16-crown-5-oxyhydroxamic acid (HL) is introduced. The extractions of UO22+, Na+, K+, Sr2+, Ba2+ and Br- were studied with HL in chloroform. The results obtained show that UO22+ can be quantitatively extracted at pH values above 5, whereas the extractions of K+, Na+, Sr2+, Ba2+ and Br- are negligible in the pH range of 2 - 7. The dependence of the distribution ratio of U(VI) on both the concentration of the HL and pH are linear, and they have the same slope of 2. This suggests that U(VI) appears to form a 1:2 complex with ligand. Uranium(VI) can be selectively separated and concentrated from interfering elements such as Na, K, Sr and Br by solvent extraction with HL under specific conditions. The recovery of uranium is nearly 100% and the radionudear purity of uranium is greater than 99.99%. Therefore, neutron activation analysis has greatly improved the sensitivity and accuracy for the detection of trace uranium from seawater.

  2. Neutron sources and applications

    Energy Technology Data Exchange (ETDEWEB)

    Price, D.L. [ed.] [Argonne National Lab., IL (United States); Rush, J.J. [ed.] [National Inst. of Standards and Technology, Gaithersburg, MD (United States)

    1994-01-01

    Review of Neutron Sources and Applications was held at Oak Brook, Illinois, during September 8--10, 1992. This review involved some 70 national and international experts in different areas of neutron research, sources, and applications. Separate working groups were asked to (1) review the current status of advanced research reactors and spallation sources; and (2) provide an update on scientific, technological, and medical applications, including neutron scattering research in a number of disciplines, isotope production, materials irradiation, and other important uses of neutron sources such as materials analysis and fundamental neutron physics. This report summarizes the findings and conclusions of the different working groups involved in the review, and contains some of the best current expertise on neutron sources and applications.

  3. Prototype Stilbene Neutron Collar

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, M. K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Shumaker, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Snyderman, N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Verbeke, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wong, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-10-26

    A neutron collar using stilbene organic scintillator cells for fast neutron counting is described for the assay of fresh low enriched uranium (LEU) fuel assemblies. The prototype stilbene collar has a form factor similar to standard He-3 based collars and uses an AmLi interrogation neutron source. This report describes the simulation of list mode neutron correlation data on various fuel assemblies including some with neutron absorbers (burnable Gd poisons). Calibration curves (doubles vs 235U linear mass density) are presented for both thermal and fast (with Cd lining) modes of operation. It is shown that the stilbene collar meets or exceeds the current capabilities of He-3 based neutron collars. A self-consistent assay methodology, uniquely suited to the stilbene collar, using triples is described which complements traditional assay based on doubles calibration curves.

  4. Versatile inelastic neutron spectrometer (VINS) project for J-PARC

    Energy Technology Data Exchange (ETDEWEB)

    Sato, T.J. [Neutron Science Laboratory, Institute for Solid State Physics, University of Tokyo, Shirakata, Tokai, Ibaraki 319-1106 (Japan)], E-mail: taku@issp.u-tokyo.ac.jp; Yamamuro, O.; Hirota, K.; Shibayama, M.; Yoshizawa, H. [Neutron Science Laboratory, Institute for Solid State Physics, University of Tokyo, Shirakata, Tokai, Ibaraki 319-1106 (Japan); Itoh, S. [High Energy Accerelator Research Organization (KEK), Oho, Tsukuba, Ibaraki 305-0801 (Japan); Watanabe, S.; Asami, T. [Neutron Science Laboratory, Institute for Solid State Physics, University of Tokyo, Shirakata, Tokai, Ibaraki 319-1106 (Japan); Kindo, K.; Uwatoko, Y. [Institute for Solid State Physics, University of Tokyo, Kashiwanoha, Chiba 277-8581 (Japan); Kanaya, T. [Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011 (Japan); Higashi, N.; Ueno, K. [High Energy Accerelator Research Organization (KEK), Oho, Tsukuba, Ibaraki 305-0801 (Japan)

    2009-02-21

    We have proposed a Versatile Inelastic Neutron Spectrometer (VINS) for the spallation neutron source at the Materials and Life Science Facility (MLF), Japan Proton Accelerator Research Complex (J-PARC). VINS is a direct-geometry Fermi chopper spectrometer designed to provide considerably high neutron flux with moderate energy and Q resolutions. VINS is characterized by its wide energy and Q range (0.5<{delta}E<1000 meV and Q< 40 A{sup -1} at {delta}E=1000 meV), enabled by an array of detectors covering large solid angle [-30 deg.<2{theta}<130 deg. horizontally and -30 deg.<{phi}<30 deg. vertically (2.8 Sr)]. Monte Carlo ray-tracing simulation estimates the sample position neutron flux as high as roughly 1x10{sup 6} neutrons cm{sup -2} s{sup -1} for the {delta}E/E{sub i}{approx}5% mode at E{sub i}=10 meV. With these wide E-Q coverage and high neutron flux, VINS will be one of the most efficient and versatile inelastic spectrometers at J-PARC. Target science ranges from conventional solid-state physics, such as highly correlated electron systems, frustrated magnets and relaxors, to rather interdisciplinary areas, exemplified by glasses, quasicrystals, polymers and liquids. A particular focus is placed on extreme sample environments; high magnetic-field and high-pressure environments are planned.

  5. Handheld dual thermal neutron detector and gamma-ray spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Stowe, Ashley C.; Burger, Arnold; Bhattacharya, Pijush; Tupitsyn, Yevgeniy

    2017-05-02

    A combined thermal neutron detector and gamma-ray spectrometer system, including: a first detection medium including a lithium chalcopyrite crystal operable for detecting neutrons; a gamma ray shielding material disposed adjacent to the first detection medium; a second detection medium including one of a doped metal halide, an elpasolite, and a high Z semiconductor scintillator crystal operable for detecting gamma rays; a neutron shielding material disposed adjacent to the second detection medium; and a photodetector coupled to the second detection medium also operable for detecting the gamma rays; wherein the first detection medium and the second detection medium do not overlap in an orthogonal plane to a radiation flux. Optionally, the first detection medium includes a .sup.6LiInSe.sub.2 crystal. Optionally, the second detection medium includes a SrI.sub.2(Eu) scintillation crystal.

  6. The DIORAMA Neutron Emitter

    Energy Technology Data Exchange (ETDEWEB)

    Terry, James Russell [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-05-05

    Emission of neutrons in a given event is modeled by the DioramaEmitterNeutron object, a subclass of the abstract DioramaEmitterModule object. The GenerateEmission method of this object is the entry point for generation of a neutron population for a given event. Shown in table 1, this method requires a number of parameters to be defined in the event definition.

  7. Anomalously high charge/orbital ordering temperature in Bi{sub 0.5}Sr{sub 0.5}MnO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Frontera, C.; Garcia-Munoz, J.L.; Carrillo, A.E. [ICMAB- CSIC, Campus de Bellaterra, 08193 Bellaterra (Spain); Aranda, M.A.G. [Depto. de Quimica Inorganica, Cristalografia y Mineralogia, Univ. de Malaga, 29071 Malaga (Spain); Ritter, C. [Institut Laue-Langevin, 38042 Grenoble-Cedex (France); Llobet, A. [Condensed Matter and Thermal Physics Group Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Ranno, L. [Lab. Louis Neel-CNRS, 38042-BP166, Grenoble Cedex 9 (France); Respaud, M.; Broto, J.M. [SNCMP and LPMC,INSA, Complexe Scientifique du Rangueil, 31077 Toulouse (France); Vanacken, J. [LVSM, Katholieke Universiteit Leuven, 3001 Leuven (Belgium); Calleja, A.; Garcia, J. [Dept. d' Enginyeria Quimica i Metallurgia, Facultat de Quimica, Univ. de Barcelona, 08028 Barcelona (Spain)

    2002-07-01

    Neutron/synchrotron diffraction data and magnetic measurements provide direct evidence of charge/orbital ordering at anomalously high temperatures in Bi{sub 0.5}Sr{sub 0.5}MnO{sub 3}, as well as in other (Bi,Sr)MnO{sub 3} manganites. We report on the electronic and magnetic transitions of these oxides. The origin of the high value of the charge/orbital ordering temperature is discussed. (orig.)

  8. Familial lipoprotein lipase deficiency

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/000408.htm Familial lipoprotein lipase deficiency To use the sharing features on this page, please enable JavaScript. Familial lipoprotein lipase deficiency is a group of rare genetic ...

  9. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... This Content: NEXT >> Featured Video Living With and Managing Iron-Deficiency Anemia 05/18/2011 This video— ... treatment. For more information about living with and managing iron-deficiency anemia, go to the Health Topics ...

  10. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... or an inability to absorb enough iron from food. Overview Iron-deficiency anemia is a common type ... of the condition. Treatments may include dietary changes, medicines, and surgery. Severe iron-deficiency anemia may require ...

  11. Folate-deficiency anemia

    Science.gov (United States)

    ... medlineplus.gov/ency/article/000551.htm Folate-deficiency anemia To use the sharing features on this page, please enable JavaScript. Folate-deficiency anemia is a decrease in red blood cells (anemia) ...

  12. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... severity of the condition. Treatments may include dietary changes, medicines, and surgery. Severe iron-deficiency anemia may require treatment in a hospital, blood ... With and Managing Iron-Deficiency Anemia 05/18/2011 This video— ...

  13. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... or an inability to absorb enough iron from food. Overview Iron-deficiency anemia is a common type ... condition. Treatments may include dietary changes, medicines, and surgery. Severe iron-deficiency anemia may require treatment in ...

  14. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... Deficiency Anemia What Is... CAUSES WHO IS AT RISK SIGNS & SYMPTOMS DIAGNOSIS TREATMENTS PREVENTION LIVING WITH CLINICAL ... and women are the two groups at highest risk for iron-deficiency anemia. Outlook Doctors usually can ...

  15. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... Deficiency Anemia Explore Iron-Deficiency Anemia What Is... CAUSES WHO IS AT RISK SIGNS & SYMPTOMS DIAGNOSIS TREATMENTS ... Google+ SITE INDEX ACCESSIBILITY PRIVACY STATEMENT FOIA NO FEAR ACT OIG CONTACT US National Institutes of Health ...

  16. Small angle neutron diffraction studies of vortex structures in high temperature superconductors

    DEFF Research Database (Denmark)

    Cubitt, R.; Forgan, E.M.; Wylie, M.T.

    1994-01-01

    We have used neutron scattering to provide direct information about flux structures in the bulk of crystals of the superconductor Bi2Sr2CaCu2O8. Its extremely high effective mass anisotropy, makes the flux lattice susceptable to melting and also to decomposition into 'pancake' vortices, which would...

  17. Neutron scattering. Experiment manuals

    Energy Technology Data Exchange (ETDEWEB)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner (eds.)

    2014-07-01

    The following topics are dealt with: The thermal triple-axis spectrometer PUMA, the high-resolution powder diffractometer SPODI, the hot-single-crystal diffractometer HEiDi, the three-axis spectrometer PANDA, the backscattering spectrometer SPHERES, the DNS neutron-polarization analysis, the neutron spin-echo spectrometer J-NSE, small-angle neutron scattering at KWS-1 and KWS-2, a very-small-angle neutron scattering diffractometer with focusing mirror, the reflectometer TREFF, the time-of-flight spectrometer TOFTOF. (HSI)

  18. Neutron-emission measurements at a white neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Haight, Robert C [Los Alamos National Laboratory

    2010-01-01

    Data on the spectrum of neutrons emittcd from neutron-induced reactions are important in basic nuclear physics and in applications. Our program studies neutron emission from inelastic scattering as well as fission neutron spectra. A ''white'' neutron source (continuous in energy) allows measurements over a wide range of neutron energies all in one experiment. We use the tast neutron source at the Los Alamos Neutron Science Center for incident neutron energies from 0.5 MeV to 200 MeV These experiments are based on double time-of-flight techniques to determine the energies of the incident and emitted neutrons. For the fission neutron measurements, parallel-plate ionization or avalanche detectors identify fission in actinide samples and give the required fast timing pulse. For inelastic scattering, gamma-ray detectors provide the timing and energy spectroscopy. A large neutron-detector array detects the emitted neutrons. Time-of-flight techniques are used to measure the energies of both the incident and emitted neutrons. Design considerations for the array include neutron-gamma discrimination, neutron energy resolution, angular coverage, segmentation, detector efficiency calibration and data acquisition. We have made preliminary measurements of the fission neutron spectra from {sup 235}U, {sup 238}U, {sup 237}Np and {sup 239}Pu. Neutron emission spectra from inelastic scattering on iron and nickel have also been investigated. The results obtained will be compared with evaluated data.

  19. Time-reversal symmetry breaking hidden order in Sr2(Ir,Rh)O4

    Science.gov (United States)

    Jeong, Jaehong; Sidis, Yvan; Louat, Alex; Brouet, Véronique; Bourges, Philippe

    2017-04-01

    Layered 5d transition iridium oxides, Sr2(Ir,Rh)O4, are described as unconventional Mott insulators with strong spin-orbit coupling. The undoped compound, Sr2IrO4, is a nearly ideal two-dimensional pseudospin-1/2 Heisenberg antiferromagnet, similarly to the insulating parent compound of high-temperature superconducting copper oxides. Using polarized neutron diffraction, we here report a hidden magnetic order in pure and doped Sr2(Ir,Rh)O4, distinct from the usual antiferromagnetic pseudospin ordering. We find that time-reversal symmetry is broken while the lattice translation invariance is preserved in the hidden order phase. The onset temperature matches that of the odd-parity hidden order recently highlighted using optical second-harmonic generation experiments. The novel magnetic order and broken symmetries can be explained by the loop-current model, previously predicted for the copper oxide superconductors.

  20. Iron-Deficiency Anemia

    Science.gov (United States)

    ... page from the NHLBI on Twitter. What Is Iron-Deficiency Anemia? Español Iron-deficiency anemia is a common, ... Content: NEXT >> Featured Video Living With and Managing Iron-Deficiency Anemia 05/18/2011 This video—presented by ...

  1. Iron-Deficiency Anemia

    Science.gov (United States)

    ... the NHLBI on Twitter. What Is Iron-Deficiency Anemia? Español Iron-deficiency anemia is a common, easily ... Featured Video Living With and Managing Iron-Deficiency Anemia 05/18/2011 This video—presented by the ...

  2. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... the NHLBI on Twitter. What Is Iron-Deficiency Anemia? Español Iron-deficiency anemia is a common, easily ... Featured Video Living With and Managing Iron-Deficiency Anemia 05/18/2011 This video—presented by the ...

  3. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... the NHLBI on Twitter. What Is Iron-Deficiency Anemia? Español Iron-deficiency anemia is a common, easily ... Featured Video Living With and Managing Iron-Deficiency Anemia 05/18/2011 This video—presented by the ...

  4. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... Deficiency Anemia? Español Iron-deficiency anemia is a common, easily treated condition that occurs if you don' ... from food. Overview Iron-deficiency anemia is a common type of anemia . The term "anemia" usually refers ...

  5. Investigation of potential fluctuating intra-unit cell magnetic order in cuprates by μ SR

    Science.gov (United States)

    Pal, A.; Akintola, K.; Potma, M.; Ishikado, M.; Eisaki, H.; Hardy, W. N.; Bonn, D. A.; Liang, R.; Sonier, J. E.

    2016-10-01

    We report low temperature muon spin relaxation (μ SR ) measurements of the high-transition-temperature (Tc) cuprate superconductors Bi2 +xSr2 -xCaCu2O8 +δ and YBa2Cu3O6.57 , aimed at detecting the mysterious intra-unit cell (IUC) magnetic order that has been observed by spin-polarized neutron scattering in the pseudogap phase of four different cuprate families. A lack of confirmation by local magnetic probe methods has raised the possibility that the magnetic order fluctuates slowly enough to appear static on the time scale of neutron scattering, but too fast to affect μ SR or nuclear magnetic resonance signals. The IUC magnetic order has been linked to a theoretical model for the cuprates, which predicts a long-range ordered phase of electron-current loop order that terminates at a quantum crictical point (QCP). Our study suggests that lowering the temperature to T ˜25 mK and moving far below the purported QCP does not cause enough of a slowing down of fluctuations for the IUC magnetic order to become detectable on the time scale of μ SR . Our measurements place narrow limits on the fluctuation rate of this unidentified magnetic order.

  6. Carnitine Deficiency and Pregnancy

    Directory of Open Access Journals (Sweden)

    Anouk de Bruyn

    2015-01-01

    Full Text Available We present two cases of carnitine deficiency in pregnancy. In our first case, systematic screening revealed L-carnitine deficiency in the first born of an asymptomatic mother. In the course of her second pregnancy, maternal carnitine levels showed a deficiency as well. In a second case, a mother known with carnitine deficiency under supplementation was followed throughout her pregnancy. Both pregnancies had an uneventful outcome. Because carnitine deficiency can have serious complications, supplementation with carnitine is advised. This supplementation should be continued throughout pregnancy according to plasma concentrations.

  7. Vacancy induced metallicity at the CaHfO3/SrTiO3 interface

    KAUST Repository

    Nazir, Safdar

    2011-03-31

    Density functional theory is used to study the electronic properties of the oxide heterointerfaceCaHfO3/SrTiO3. Structural relaxation is carried out with and without O vacancies. As compared to related interfaces, strongly reduced octahedral distortions are found. Stoichiometric interfaces between the wide band gap insulatorsCaHfO3 and SrTiO3 turn out to exhibit an insulating state. However, interface metallicity is introduced by O vacancies, in agreement with experiment. The reduced octahedral distortions and necessity of O deficiency indicate a less complicated mechanism for the creation of the interfacial electron gas.

  8. Neutron resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gunsing, F

    2005-06-15

    The present document has been written in order to obtain the diploma 'Habilitation a Diriger des Recherches'. Since this diploma is indispensable to supervise thesis students, I had the intention to write a document that can be useful for someone starting in the field of neutron resonance spectroscopy. Although the here described topics are already described elsewhere, and often in more detail, it seemed useful to have most of the relevant information in a single document. A general introduction places the topic of neutron-nucleus interaction in a nuclear physics context. The large variations of several orders of magnitude in neutron-induced reaction cross sections are explained in terms of nuclear level excitations. The random character of the resonances make nuclear model calculation predictions impossible. Then several fields in physics where neutron-induced reactions are important and to which I have contributed in some way or another, are mentioned in a first synthetic chapter. They concern topics like parity nonconservation in certain neutron resonances, stellar nucleosynthesis by neutron capture, and data for nuclear energy applications. The latter item is especially important for the transmutation of nuclear waste and for alternative fuel cycles. Nuclear data libraries are also briefly mentioned. A second chapter details the R-matrix theory. This formalism is the foundation of the description of the neutron-nucleus interaction and is present in all fields of neutron resonance spectroscopy. (author)

  9. Development of Neutron Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chang Hee; Lee, J. S.; Seong, B. S. (and others)

    2007-06-15

    Neutron spectrometers which are used in the basic researches such as physics, chemistry and materials science and applied in the industry were developed at the horizontal beam port of HANARO reactor. In addition, the development of core components for neutron scattering and the upgrade of existing facilities are also performed. The vertical neutron reflectometer was fabricated and installed at ST3 beam port. The performance test of the reflectometer was completed and the reflectometer was opened to users. The several core parts and options were added in the polarized neutron spectrometer. The horizontal neutron reflectometer from Brookhaven National Laboratory was moved to HANARO and installed, and the performance of the reflectometer was examined. The HIPD was developed and the performance test was completed. The base shielding for TAS was fabricated. The soller collimator, Cu mosaic monochromator, Si BPC monochromator and position sensitive detector were developed and applied in the neutron spectrometer as part of core component development activities. In addition, the sputtering machine for mirror device are fabricated and the neutron mirror is made using the sputtering machine. The FCD was upgraded and the performance of the FCD are improved over the factor of 10. The integration and upgrade of the neutron detection system were also performed.

  10. Neutron Star Matter

    CERN Document Server

    Wambach, Jochen

    2013-01-01

    In this presentation I discuss two aspects of the neutron-matter equation of state. One relates to the symmetry energy of nuclear matter and empirical constraints on its slope parameter at saturation density. The second deals with spatially inhomogeneous chiral phases of deconfined quark matter in the inner core of a neutron star.

  11. Neutron Multiplicity Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Frame, Katherine Chiyoko [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-06-28

    Neutron multiplicity measurements are widely used for nondestructive assay (NDA) of special nuclear material (SNM). When combined with isotopic composition information, neutron multiplicity analysis can be used to estimate the spontaneous fission rate and leakage multiplication of SNM. When combined with isotopic information, the total mass of fissile material can also be determined. This presentation provides an overview of this technique.

  12. Neutron capture therapies

    Energy Technology Data Exchange (ETDEWEB)

    Yanch, Jacquelyn C. (Cambridge, MA); Shefer, Ruth E. (Newton, MA); Klinkowstein, Robert E. (Winchester, MA)

    1999-01-01

    In one embodiment there is provided an application of the .sup.10 B(n,.alpha.).sup.7 Li nuclear reaction or other neutron capture reactions for the treatment of rheumatoid arthritis. This application, called Boron Neutron Capture Synovectomy (BNCS), requires substantially altered demands on neutron beam design than for instance treatment of deep seated tumors. Considerations for neutron beam design for the treatment of arthritic joints via BNCS are provided for, and comparisons with the design requirements for Boron Neutron Capture Therapy (BNCT) of tumors are made. In addition, exemplary moderator/reflector assemblies are provided which produce intense, high-quality neutron beams based on (p,n) accelerator-based reactions. In another embodiment there is provided the use of deuteron-based charged particle reactions to be used as sources for epithermal or thermal neutron beams for neutron capture therapies. Many d,n reactions (e.g. using deuterium, tritium or beryllium targets) are very prolific at relatively low deuteron energies.

  13. Neutron capture therapies

    Energy Technology Data Exchange (ETDEWEB)

    Yanch, J.C.; Shefer, R.E.; Klinkowstein, R.E.

    1999-11-02

    In one embodiment there is provided an application of the {sup 10}B(n,{alpha}){sup 7}Li nuclear reaction or other neutron capture reactions for the treatment of rheumatoid arthritis. This application, called Boron Neutron Capture Synovectomy (BNCS), requires substantially altered demands on neutron beam design than for instance treatment of deep seated tumors. Considerations for neutron beam design for the treatment of arthritic joints via BNCS are provided for, and comparisons with the design requirements for Boron Neutron Capture Therapy (BNCT) of tumors are made. In addition, exemplary moderator/reflector assemblies are provided which produce intense, high-quality neutron beams based on (p,n) accelerator-based reactions. In another embodiment there is provided the use of deuteron-based charged particle reactions to be used as sources for epithermal or thermal neutron beams for neutron capture therapies. Many d,n reactions (e.g. using deuterium, tritium or beryllium targets) are very prolific at relatively low deuteron energies.

  14. Genesis of Sr Isotopes in Groundwater of Hebei Plain

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    To analyze the genesis of Sr isotopes in groundwater of Hebei plain, time-accumulative effect of 87Sr/86Sr ratio was studied. It is shown that 87Sr/86Sr ratio increases with the increasing age and depth of groundwater and has a positive correlation to 4Heexc and a negative correlation to δ18O and δD.The groundwater is divided into three groups to discuss the relation between 87Sr/86Sr ratio and Sr2+ content: ① moderate Sr2+ content and higher 87Sr/86Sr ratio (water Ⅰ); ② lower Sr2+ content and higher 87Sr/86Sr ratio (water Ⅱ); and ③ higher Sr2+ content and lower 87Sr/86Sr ratio (water Ⅲ), that is hot water. On the basis of integrated analysis, it was considered that ① the radiogenic Sr in the Quaternary groundwater (Q4-Q1) originates from weathering of silicate rich in Na and Rb, mainly from plagioclase; ② the radiogenic Sr of hot water in Huanghua port is attributed to carbonate dissolution, with lower 87Sr/86Sr ratio and higher Sr/Na ratio; ③ the recharge area is laterally recharged by the groundwater flowing through igneous and metamorphic rocks, with moderate 87Sr/86Sr ratio. However, the formation mechanism of Sr isotopes in Tertiary groundwater needs further studies.

  15. Cenozoic seawater Sr/Ca evolution

    Science.gov (United States)

    Sosdian, Sindia M.; Lear, Caroline H.; Tao, Kai; Grossman, Ethan L.; O'Dea, Aaron; Rosenthal, Yair

    2012-10-01

    Records of seawater chemistry help constrain temporal variations in geochemical processes that impact the global carbon cycle and climate through Earth's history. Here we reconstruct Cenozoic seawater Sr/Ca (Sr/Casw) using fossil Conus and turritellid gastropod Sr/Ca. Combined with an oxygen isotope paleotemperature record from the same samples, the gastropod record suggests that Sr/Caswwas slightly higher in the Eocene (˜11.4 ± 3 mmol/mol) than today (˜8.54 mmol/mol) and remained relatively stable from the mid- to late Cenozoic. We compare our gastropod Cenozoic Sr/Casw record with a published turritellid gastropod Sr/Casw record and other published biogenic (benthic foraminifera, fossil fish teeth) and inorganic precipitate (calcite veins) Sr/Caswrecords. Once the uncertainties with our gastropod-derived Sr/Casw are taken into account the Sr/Casw record agrees reasonably well with biogenic Sr/Caswrecords. Assuming a seawater [Ca] history derived from marine evaporite inclusions, all biogenic-based Sr/Casw reconstructions imply decreasing seawater [Sr] through the Cenozoic, whereas the calcite vein Sr/Casw reconstruction implies increasing [Sr] through the Cenozoic. We apply a simple geochemical model to examine the implications of divergence among these seawater [Sr] reconstructions and suggest that the interpretation and uncertainties associated with the gastropod and calcite vein proxies need to be revisited. Used in conjunction with records of carbonate depositional fluxes, our favored seawater Sr/Ca scenarios point to a significant increase in the proportion of aragonite versus calcite deposition in shelf sediments from the Middle Miocene, coincident with the proliferation of coral reefs. We propose that this occurred at least 10 million years after the seawater Mg/Ca threshold was passed, and was instead aided by declining levels of atmospheric carbon dioxide.

  16. Neutron Stars and Pulsars

    CERN Document Server

    Becker, Werner

    2009-01-01

    Neutron stars are the most compact astronomical objects in the universe which are accessible by direct observation. Studying neutron stars means studying physics in regimes unattainable in any terrestrial laboratory. Understanding their observed complex phenomena requires a wide range of scientific disciplines, including the nuclear and condensed matter physics of very dense matter in neutron star interiors, plasma physics and quantum electrodynamics of magnetospheres, and the relativistic magneto-hydrodynamics of electron-positron pulsar winds interacting with some ambient medium. Not to mention the test bed neutron stars provide for general relativity theories, and their importance as potential sources of gravitational waves. It is this variety of disciplines which, among others, makes neutron star research so fascinating, not only for those who have been working in the field for many years but also for students and young scientists. The aim of this book is to serve as a reference work which not only review...

  17. THERMAL NEUTRON BACKSCATTER IMAGING.

    Energy Technology Data Exchange (ETDEWEB)

    VANIER,P.; FORMAN,L.; HUNTER,S.; HARRIS,E.; SMITH,G.

    2004-10-16

    Objects of various shapes, with some appreciable hydrogen content, were exposed to fast neutrons from a pulsed D-T generator, resulting in a partially-moderated spectrum of backscattered neutrons. The thermal component of the backscatter was used to form images of the objects by means of a coded aperture thermal neutron imaging system. Timing signals from the neutron generator were used to gate the detection system so as to record only events consistent with thermal neutrons traveling the distance between the target and the detector. It was shown that this time-of-flight method provided a significant improvement in image contrast compared to counting all events detected by the position-sensitive {sup 3}He proportional chamber used in the imager. The technique may have application in the detection and shape-determination of land mines, particularly non-metallic types.

  18. Pocked surface neutron detector

    Energy Technology Data Exchange (ETDEWEB)

    McGregor, Douglas (Whitmore Lake, MI); Klann, Raymond (Bolingbrook, IL)

    2003-04-08

    The detection efficiency, or sensitivity, of a neutron detector material such as of Si, SiC, amorphous Si, GaAs, or diamond is substantially increased by forming one or more cavities, or holes, in its surface. A neutron reactive material such as of elemental, or any compound of, .sup.10 B, .sup.6 Li, .sup.6 LiF, U, or Gd is deposited on the surface of the detector material so as to be disposed within the cavities therein. The portions of the neutron reactive material extending into the detector material substantially increase the probability of an energetic neutron reaction product in the form of a charged particle being directed into and detected by the neutron detector material.

  19. Neutron stars - General review

    Science.gov (United States)

    Cameron, A. G. W.; Canuto, V.

    1974-01-01

    A review is presented of those properties of neutron stars upon which there is general agreement and of those areas which currently remain in doubt. Developments in theoretical physics of neutron star interiors are summarized with particular attention devoted to hyperon interactions and the structure of interior layers. Determination of energy states and the composition of matter is described for successive layers, beginning with the surface and proceeding through the central region into the core. Problems encountered in determining the behavior of matter in the ultra-high density regime are discussed, and the effects of the magnetic field of a neutron star are evaluated along with the behavior of atomic structures in the field. The evolution of a neutron star is outlined with discussion centering on carbon detonation, cooling, vibrational damping, rotation, and pulsar glitches. The role of neutron stars in cosmic-ray propagation is considered.

  20. 88Sr/86Sr fractionation in inorganic aragonite and in corals

    Science.gov (United States)

    Fruchter, Noa; Eisenhauer, Anton; Dietzel, Martin; Fietzke, Jan; Böhm, Florian; Montagna, Paolo; Stein, Moti; Lazar, Boaz; Rodolfo-Metalpa, Riccardo; Erez, Jonathan

    2016-04-01

    Conflicting results have been reported for the stable Sr isotope fractionation, specifically with respect to the influence of temperature. In an experimental study we have investigated the stable Sr isotope systematics for inorganically precipitated and biogenic (coral) aragonite (natural and laboratory-cultured). Inorganic aragonite precipitation experiments were performed from natural seawater using the CO2 diffusion technique. The experiments were performed at different temperatures and different carbonate ion concentrations. 88Sr/86Sr of the inorganic aragonite precipitated in the experiments are 0.2‰ lighter than seawater, but showed no correlation to the water temperature or to CO32- concentration. Similar observations are made in different coral species (Cladocora caespitosa, Porites sp. and Acropora sp.), with identical fractionation from the bulk solution and no correlation to temperature or CO32- concentration. The lack of 88Sr/86Sr variability in corals at different environmental parameters and the similarity to the 88Sr/86Sr fractionation in inorganic aragonite may indicate a similar Sr incorporation mechanism in corals skeleton and inorganic aragonite, and therefore the previously proposed Rayleigh-based multi element model (Gaetani et al., 2011) cannot explain the process of Sr incorporation in the coral skeletal material. It is proposed that the relatively constant 88Sr/86Sr fractionation in aragonite can be used for paleo reconstruction of seawater 88Sr/86Sr composition. The seawater 88Sr/86Sr ratio reconstruction can be further used in calcite samples to reconstruct paleo precipitation rates.

  1. Possible insect vectors of phytoplasmas affiliated with subgroups 16SrI-B, 16SrI-C, 16SrIII-B and 16SrIII-P in Lithuania

    Science.gov (United States)

    Phytoplasma strains affiliated with groups 16SrI, 16SrIII, 16SrV, and 16SrXII have been found in Lithuania, but still little is known about insects that could transmit them. In this study, four phytoplasma strains belonging to phytoplasma subgroups 16SrI-B, 16SrI-C, 16SrIII-B and 16SrIII-P were id...

  2. SINGLE CRYSTAL NEUTRON DIFFRACTION.

    Energy Technology Data Exchange (ETDEWEB)

    KOETZLE,T.F.

    2001-03-13

    Single-crystal neutron diffraction measures the elastic Bragg reflection intensities from crystals of a material, the structure of which is the subject of investigation. A single crystal is placed in a beam of neutrons produced at a nuclear reactor or at a proton accelerator-based spallation source. Single-crystal diffraction measurements are commonly made at thermal neutron beam energies, which correspond to neutron wavelengths in the neighborhood of 1 Angstrom. For high-resolution studies requiring shorter wavelengths (ca. 0.3-0.8 Angstroms), a pulsed spallation source or a high-temperature moderator (a ''hot source'') at a reactor may be used. When complex structures with large unit-cell repeats are under investigation, as is the case in structural biology, a cryogenic-temperature moderator (a ''cold source'') may be employed to obtain longer neutron wavelengths (ca. 4-10 Angstroms). A single-crystal neutron diffraction analysis will determine the crystal structure of the material, typically including its unit cell and space group, the positions of the atomic nuclei and their mean-square displacements, and relevant site occupancies. Because the neutron possesses a magnetic moment, the magnetic structure of the material can be determined as well, from the magnetic contribution to the Bragg intensities. This latter aspect falls beyond the scope of the present unit; for information on magnetic scattering of neutrons see Unit 14.3. Instruments for single-crystal diffraction (single-crystal diffractometers or SCDs) are generally available at the major neutron scattering center facilities. Beam time on many of these instruments is available through a proposal mechanism. A listing of neutron SCD instruments and their corresponding facility contacts is included in an appendix accompanying this unit.

  3. Upper limit to magnetism in LaAIO3/SrTiO3 heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Fitzsimmons, Michael R [Los Alamos National Laboratory

    2012-02-27

    In 2004 Ohtomo and Hwang reported unusually high conductivity in LaAl03 and SrTi03 bilayer samples. Since then, metallic conduction, superconductivity, magnetism, and coexistence of superconductivity and ferromagnetism have been attributed to LaAl03/SrTi03 interfaces. Very recently, two studies have reported large magnetic moments attributed to interfaces from measurement techniques that are unable to distinguish between interfacial and bulk magnetism. Consequently, it is imperative to perform magnetic measurements that by being intrinsically sensitive to interface magnetism are impervious to experimental artifacts suffered by bulk measurements. Using polarized neutron reflectometry we measured the neutron spin dependent reflectivity from four LaAl03/SrTi03 superlattices. Our results indicate the upper limit for the magnetization averaged over the lateral dimensions of the sample induced by an 11 T magnetic field at 1.7 K is less than 2 G. SQUID magnetometry of the neutron superlattice samples sporadically finds an enhanced moment (consistent with past reports), possibly due to experimental artifacts. These observations set important restrictions on theories which imply a strongly enhanced magnetism at the interface between LaAI03 and SrTi03.

  4. The role of the class A scavenger receptors, SR-A and MARCO, in the immune system. Part 1. The structure of receptors, their ligand binding repertoires and ability to initiate intracellular signaling

    Directory of Open Access Journals (Sweden)

    Szczepan Józefowski

    2012-02-01

    Full Text Available  Recognition of pathogens by innate immune cells is mediated by pattern recognition receptors (PRR, which include scavenger receptors (SR. The class A SR, SR-A/CD204 and MARCO, are characterized by the presence of collagenous and SR cysteine-rich domains in their extracellular portions. Both receptors are expressed mainly on macrophages and dendritic cells. Thanks to their ability to bind to a wide range of polyanionic ligands, the class A SR may participate in numerous functions of these cells, such as endocytosis, and adhesion to extracellular matrix and to other cells. Among SR-A ligands are oxidized lipoproteins and β-amyloid fibrils, which link SR-A to the pathogenesis of arteriosclerosis and Alzheimer’s disease. Despite the demonstration of class A SR involvement in so many processes, the lack of selective ligands precluded reaching definite conclusions concerning their signaling abilities. Using specific receptor ligation with antibodies, we showed that SR-A and MARCO trigger intracellular signaling, modulating pro-inflammatory and microbicidal activities of macrophages. Surprisingly, despite similarities in structure and ligand binding repertoires, SR-A and MARCO exert opposite effects on interleukin-12 (IL-12 production in macrophages. SR-A ligation also stimulated H2O2 and IL-10 production, but had no effect on the release of several other cytokines. These limited effects of specific SR-A ligation contrast with generalized enhancement of immune responses observed in SR-A-deficient mice. Recent studies have revealed that many of these effects of SR-A deficiency may be caused by compensatory changes in the expression of other receptors and/or disinhibition of signal transduction from receptors belonging to the Toll/IL-1R family, rather than by the loss of the receptor function of SR-A.

  5. Sr partitioning in the benthic foraminifera

    NARCIS (Netherlands)

    Langer, G.; Sadekov, A.; Thoms, S.; Keul, N.; Nehrke, G.; Mewes, A.; Greaves, M.; Misra, S.; Reichart, G.-J.; de Nooijer, L.J.; Bijma, J.; Elderfield, H.

    2016-01-01

    The shallow water benthic foraminifera Ammonia aomoriensis and Amphistegina lessonii were grown at differentseawater Sr/Ca and the test Sr/Ca ratio was determined by Laser Ablation - Inductively Coupled Plasma - MassSpectrometry. A. aomoriensis test Sr/Ca is positively correlated with seawater

  6. Accurate mass measurements on neutron-deficient krypton isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, D. [GSI, Planckstrasse 1, 64291 Darmstadt (Germany)]. E-mail: rodriguez@lpccaen.in2p3.fr; Audi, G. [CSNSM-IN2P3-CNRS, 91405 Orsay-Campus(France); Aystoe, J. [University of Jyvaeskylae, Department of Physics, P.O. Box 35, 40351 Jyvaeskylae (Finland); Beck, D. [GSI, Planckstrasse 1, 64291 Darmstadt (Germany); Blaum, K. [GSI, Planckstrasse 1, 64291 Darmstadt (Germany); Institute of Physics, University of Mainz, Staudingerweg 7, 55128 Mainz (Germany); Bollen, G. [NSCL, Michigan State University, East Lansing, MI 48824-1321 (United States); Herfurth, F. [GSI, Planckstrasse 1, 64291 Darmstadt (Germany); Jokinen, A. [University of Jyvaeskylae, Department of Physics, P.O. Box 35, 40351 Jyvaeskylae (Finland); Kellerbauer, A. [CERN, Division EP, 1211 Geneva 23 (Switzerland); Kluge, H.-J. [GSI, Planckstrasse 1, 64291 Darmstadt (Germany); University of Heidelberg, 69120 Heidelberg (Germany); Kolhinen, V.S. [University of Jyvaeskylae, Department of Physics, P.O. Box 35, 40351 Jyvaeskylae (Finland); Oinonen, M. [Helsinki Institute of Physics, P.O. Box 64, 00014 University of Helsinki (Finland); Sauvan, E. [Institute of Physics, University of Mainz, Staudingerweg 7, 55128 Mainz (Germany); Schwarz, S. [NSCL, Michigan State University, East Lansing, MI 48824-1321 (United States)

    2006-04-17

    The masses of {sup 72-78,80,82,86}Kr were measured directly with the ISOLTRAP Penning trap mass spectrometer at ISOLDE/CERN. For all these nuclides, the measurements yielded mass uncertainties below 10 keV. The ISOLTRAP mass values for {sup 72-75}Kr outweighed previous results obtained by means of other techniques, and thus completely determine the new values in the Atomic-Mass Evaluation. Besides the interest of these masses for nuclear astrophysics, nuclear structure studies, and Standard Model tests, these results constitute a valuable and accurate input to improve mass models. In this paper, we present the mass measurements and discuss the mass evaluation for these Kr isotopes.

  7. Accurate mass measurements on neutron-deficient krypton isotopes

    CERN Document Server

    Rodríguez, D; Äystö, J; Beck, D

    2006-01-01

    The masses of $^{72–78,80,82,86}$Kr were measured directly with the ISOLTRAP Penning trap mass spectrometer at ISOLDE/CERN. For all these nuclides, the measurements yielded mass uncertainties below 10 keV. The ISOLTRAP mass values for $^{72–75}$Kr being more precise than the previous results obtained by means of other techniques, and thus completely determine the new values in the Atomic-Mass Evaluation. Besides the interest of these masses for nuclear astrophysics, nuclear structure studies, and Standard Model tests, these results constitute a valuable and accurate input to improve mass models. In this paper, we present the mass measurements and discuss the mass evaluation for these Kr isotopes.

  8. Projected shell model study of neutron-deficient 122Ce

    Indian Academy of Sciences (India)

    Rani Devi; B D Sehgal; S K Khosa

    2006-09-01

    The observed excited states of 122Ce nucleus have been studied in the frame-work of projected shell model (PSM). The yrast band has been studied up to spin 26 ħ. The first band crossing has been predicted above a rotational frequency of 0.4 MeV/ħ that corresponds to first backbending. The calculation reproduces the experimentally observed ground state band up to spin 14ħ. The electromagnetic quantities, transition quadrupole moments and -factors are predicted and there is a need to measure these quantities experimentally.

  9. Optical polarizing neutron devices designed for pulsed neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, M.; Kurahashi, K.; Endoh, Y. [Tohoku Univ, Sendai (Japan); Itoh, S. [National Lab. for High Energy Physics, Tsukuba (Japan)

    1997-09-01

    We have designed two polarizing neutron devices for pulsed cold neutrons. The devices have been tested at the pulsed neutron source at the Booster Synchrotron Utilization Facility of the National Laboratory for High Energy Physics. These two devices proved to have a practical use for experiments to investigate condensed matter physics using pulsed cold polarized neutrons.

  10. On the real structure of profiled anion-deficient corundum

    Science.gov (United States)

    Maksimov, V. I.; Sokolov, V. I.; Surdo, A. I.; Abashev, R. M.; Yushkova, E. N.

    2017-02-01

    Profiled Al2O3 single crystals grown by Stepanov’s method to obtain anion-deficient composition were characterized by neutron diffraction at T=300 K for the first time. Whereas the main structure motif of investigated crystals is checked to be of corundum-type, the scattering pictures of as-grown crystal demonstrate pronounced anomalies being probably indications on substructure forming. However, neutron scanning of synthesised crystal taken after annealing under restoring conditions reveals additional effects associated with displacement type superstructure.

  11. Analysis of human enamel and dentine by neutron activation analysis; Analise de esmalte e dentina de humanos pelo metodo de ativacao com neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Marco A.B. [Sao Paulo Univ., SP (Brazil). Inst. de Quimica]. E-mail: vankfire@gmail.com; Adachi, Eduardo M.; Saiki, Mitiko [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

    2005-07-01

    Determination of trace elements in dental tissues has been of great interest to study the correlation between element composition and caries as well as food habits of individuals. In the present study dentine and enamel samples from healthy individuals were analysed by neutron activation analysis. The teeth were provided form dental clinics, and they were previously washed using purified water and acetone. Then they were dried at 40 deg C and ground in a agate mortar. The samples and element standards were irradiated with thermal neutrons at the IEA-R1 nuclear reactor. Long irradiations of 8 h under thermal neutron flux of 5x10{sup 12} n cm{sup -2} s{sup -1} were used for Ca, Na, Sr and Zn determinations. In short irradiations of 15 s and under neutron flux of 10{sup 12} n cm{sup -2} s{sup -1} the elements Mg, Mn, Na e Sr were determined. The induced gamma activities of the samples and standards were measured using a hyperpure Ge detector coupled to a gamma ray spectrometer. Elemental concentrations were calculated by comparative method. Results obtained showed that Ca, Mg and Na are present in both tissues at the level of percentages and the elements Mn, Sr and Zn at the {mu}g g{sup -1} levels. For quality control of the results the certified reference materials NIST 1400 Bone Ash and NIST 1486 Bone Meal were analysed. (author)

  12. Calculation of Ambient (H*(10)) and Personal (Hp(10)) Dose Equivalent from a 252Cf Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    Traub, Richard J.

    2010-03-26

    The purpose of this calculation is to calculate the neutron dose factors for the Sr-Cf-3000 neutron source that is located in the 318 low scatter room (LSR). The dose factors were based on the dose conversion factors published in ICRP-21 Appendix 6, and the Ambient dose equivalent (H*(10)) and Personal dose equivalent (Hp(10)) dose factors published in ICRP Publication 74.

  13. Fail-safe neutron shutter used for thermal neutron radiography

    Energy Technology Data Exchange (ETDEWEB)

    Sachs, R.D.; Morris, R.A.

    1976-11-01

    A fail-safe, reliable, easy-to-use neutron shutter was designed, built, and put into operation at the Omega West Reactor, Los Alamos Scientific Laboratory. The neutron shutter will be used primarily to perform thermal neutron radiography, but is also available for a highly collimated source of thermal neutrons (neutron flux = 3.876 x 10/sup 6/ (neutrons)/(cm/sup 2/.s)). Neutron collimator sizes of either 10.16 by 10.16 cm or 10.16 by 30.48 cm are available.

  14. Rapid method for determining Sr-89 and Sr-90 using Cherenkov and proportional counting; Schnellmethode zur Bestimmung von SR-89 und SR-90 durch Cerenkov- und Proportionalzaehlermessungen

    Energy Technology Data Exchange (ETDEWEB)

    Lange, S.; Wende, C.; Schwokowski, R.; Alisch-Mark, M.; Abraham, A.; Heinrich, T. [Staatliche Betriebsgesellschaft fuer Umwelt und Landwirtschaft, Radebeul (Germany)

    2016-07-01

    A rapid method for determining Sr-89 and Sr-90 in water, milk and biological samples has been developed and tested. After sample preparation strontium is separated by extraction chromatography using Sr resin. Eluate is divided and transfered to LSC vial and filter paper by SrCO{sub 3} precipitation. A Hidex 300 SL TDCR liquid scintillation counter and Thermo Fisher low level proportional counter have been used. Chemical yield of Sr-85 tracer is determined by Gamma spectroscopy. Uncertainty budget, decision threshold and detection limit are calculated in accordance with GUM and ISO 11929.

  15. Acquired color vision deficiency.

    Science.gov (United States)

    Simunovic, Matthew P

    2016-01-01

    Acquired color vision deficiency occurs as the result of ocular, neurologic, or systemic disease. A wide array of conditions may affect color vision, ranging from diseases of the ocular media through to pathology of the visual cortex. Traditionally, acquired color vision deficiency is considered a separate entity from congenital color vision deficiency, although emerging clinical and molecular genetic data would suggest a degree of overlap. We review the pathophysiology of acquired color vision deficiency, the data on its prevalence, theories for the preponderance of acquired S-mechanism (or tritan) deficiency, and discuss tests of color vision. We also briefly review the types of color vision deficiencies encountered in ocular disease, with an emphasis placed on larger or more detailed clinical investigations.

  16. Mechanism for Curie temperature variation in La{sub x}Sr{sub 2-x}FeMoO{sub 6} and Ca{sub x}Sr{sub 2-x}FeMoO{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Frontera, C.; Rubi, D.; Navarro, J.; Garcia-Munoz, J.L.; Ritter, C.; Fontcuberta, J

    2004-07-15

    By means of high-resolution neutron powder diffraction at 10 K, we have characterized the structural details of La{sub x}Sr{sub 2-x}FeMoO{sub 6} (0{<=}x{<=}0.5) and Ca{sub x}Sr{sub 2-x}FeMoO{sub 6} (0{<=}x{<=}0.6) series of compounds. The Curie temperature (T{sub C}) raises in the La series and slightly decreases in the Ca one. The enhancement of T{sub C} in the La series is attributed to the effect of the conduction band-filling when doping with La.

  17. Beta-delayed neutron emission studies with a C7LYC array at CARIBU

    Science.gov (United States)

    Wilson, Gemma; Chowdhury, Partha; Lister, Christopher; Brown, Tristan; Carpenter, Michael; Chillery, Thomas; Copp, Patrick; Doucet, Emery; Mitchell, Alan; Savard, Guy; Zhu, Shaofei

    2016-09-01

    This work is a study of β-delayed neutron and γ emission from 94Rb at CARIBU. Beta-delayed neutron emission studies are important in the astrophysical r-process, nuclear structure and for nuclear reactor safety and design. Approximately 150 γ rays are known in the daughter 94Sr, many of which are unplaced. An estimated 26% of γ rays are thought to be missing. The probability of β-delayed neutron emission in 94Sr is 10.2(2)%. Recently, substantial γ-decay from above the neutron separation energy in 94Rb has been reported. This research is aimed at understanding this high-lying γ-strength. The experiment employed the X-Array (a high efficiency HPGe clover array), SCANS (Small CLYC Array for Neutron Scattering) and the SATURN decay station (Scintillator And Tape Using Radioactive Nuclei) for γ, fast neutron and β-particle detection, respectively. Data were collected in a triggerless digital data acquisition system, with detected β , n , and γ events correlated offline. Techniques, analysis and first results will be discussed. Supported by the NNSA Stewardship Science Academic Alliance Program under Grant DE-NA00013008, and by US DoE, Office of Nuclear Physics, under DE-FG02-94ER40848.

  18. Neutron scattering in liquids

    Energy Technology Data Exchange (ETDEWEB)

    Barocchi, F. [Florence Univ. (Italy). Ist. di Fisica

    1996-12-31

    Together with X-rays, thermal neutrons are the ideal probe to study the microscopic structure of condensed matter, however the precision attainable usually with neutrons for the measurement of atomic position correlation functions in liquids is, at least, one order of magnitude better than for X-rays. In order to measure properly the microscopic dynamics a wide range of momentum transfer with corresponding energy transfer must be available in the range of liquid state excitations. This again is only attainable, with good resolution, with neutrons. (author) 7 figs., 3 refs.

  19. Neutrons in soft matter

    CERN Document Server

    Imae, Toyoko; Furusaka, Michihiro; Torikai, Naoya

    2011-01-01

    Neutron and synchrotron facilities, which are beyond the scale of the laboratory, and supported on a national level in countries throughout the world.  These tools for probing micro- and nano-structure research and on fast dynamics research of atomic location in materials have been key in the development of new polymer-based materials. Different from several existing professional books on neutron science, this book focuses on theory, instrumentation, an applications. The book is divided into five parts: Part 1 describes the underlying theory of neutron scattering. Part 2 desc

  20. Upper limit to magnetism in LaAlO3/SrTiO3 heterostructures

    Science.gov (United States)

    Fitzsimmons, Michael

    2012-02-01

    In 2004 Ohtomo and Hwang reported unusually high conductivity in LaAlO3 and SrTiO3 bilayer samples. Since then, metallic conduction, superconductivity, magnetism, and coexistence of superconductivity and ferromagnetism have been attributed to LaAlO3/SrTiO3 interfaces. Very recently, two studies have reported large magnetic moments attributed to interfaces from measurement techniques that are unable to distinguish between interfacial and bulk magnetism. Consequently, it is imperative to perform magnetic measurements that by being intrinsically sensitive to interface magnetism are impervious to experimental artifacts suffered by bulk measurements. Using polarized neutron reflectometry, we measured the neutron spin dependent reflectivity from four LaAlO3/SrTiO3 superlattices. Our results indicate the upper limit for the magnetization averaged over the lateral dimensions of the sample induced by an 11 T magnetic field at 1.7 K is less than 2 G. SQUID magnetometry of the neutron superlattice samples sporadically finds an enhanced moment (consistent with past reports), possibly due to experimental artifacts. These observations set important restrictions on theories which imply a strongly enhanced magnetism at the interface between LaAlO3 and SrTiO3. Work performed in collaboration with N.W. Hengartner, S. Singh, M. Zhernenkov (LANL), F.Y. Bruno, J. Santamaria (Universidad Complutense de Madrid), A. Brinkman, M.J.A. Huijben, H. Molegraaf (MESA+ Institute for Nanotechnology), J. de la Venta and Ivan K. Schuller (UCSD). [4pt] Work supported by the Office of Basic Energy Science, U.S. Department of Energy, BES-DMS and DMR under grant DE FG03-87ER-45332. Work at UCM is supported by Consolider Ingenio CSD2009-00013 (IMAGINE), CAM S2009-MAT 1756 (PHAMA) and work at Twente is supported by the Foundation for Fundamental Research on Matter (FOM).

  1. Two-Quasiparticle Bands and Isomers in 98Sr

    Institute of Scientific and Technical Information of China (English)

    LI Ming-Liang; I.Y.Lee; J.O.Rasmussen; Y.X.Luo; W.C.Ma; ZHU Sheng-Jiang; J.H.Hamilton; A.V.Ramayya; J.K.Hwang; CHE Xing-Lai; ZHANG Zheng; YU Ying-Nan; ZHENG Ran-Cheng

    2004-01-01

    @@ Rotational bands in neutron-rich 98Sr nucleus have been investigated by measuring high-fold prompt γ-ray coincidence events of the spontaneous fission of 252Cf with the Gammasphere detector array. A deformed K = 3band built on the 1838keV level has been confirmed and extended. Another deformed K = 6 band based on the 2535keV level has been established. Both the bands originate most probably from the v9/2[404] ( )v3/2[411] twoquasiparticle configuration with Ω = |Ω1 - Ω2| and Ω= |Ω1 + Ω2|, respectively. Based on the delay-coincidence measurements, the half-lives for the K = 3 and K = 6 band head levels have been obtained to be 13 ± 3 ns and 4.5 ± 1.0 ns, respectively.

  2. Persistent optically induced magnetism in oxygen-deficient strontium titanate.

    Science.gov (United States)

    Rice, W D; Ambwani, P; Bombeck, M; Thompson, J D; Haugstad, G; Leighton, C; Crooker, S A

    2014-05-01

    Strontium titanate (SrTiO3) is a foundational material in the emerging field of complex oxide electronics. Although its bulk electronic and optical properties are rich and have been studied for decades, SrTiO3 has recently become a renewed focus of materials research catalysed in part by the discovery of superconductivity and magnetism at interfaces between SrTiO3 and other non-magnetic oxides. Here we illustrate a new aspect to the phenomenology of magnetism in SrTiO3 by reporting the observation of an optically induced and persistent magnetization in slightly oxygen-deficient bulk SrTiO3-δ crystals using magnetic circular dichroism (MCD) spectroscopy and SQUID magnetometry. This zero-field magnetization appears below ~18 K, persists for hours below 10 K, and is tunable by means of the polarization and wavelength of sub-bandgap (400-500 nm) light. These effects occur only in crystals containing oxygen vacancies, revealing a detailed interplay between magnetism, lattice defects, and light in an archetypal complex oxide material.

  3. Lattice Instability and Competing Spin Structures in the Double Perovskite Insulator Sr2FeOsO6

    OpenAIRE

    Avijit Kumar Paul; Manfred Reehuis; Vadim Ksenofontov; Binghai Yan; Andreas Hoser; Többens, Daniel M.; Abdala, Paula M.; Peter Adler; Martin Jansen; Claudia Felser

    2013-01-01

    The semiconductor Sr2FeOsO6, depending on temperature, adopts two types of spin structures that differ in the spin sequence of ferrimagnetic iron - osmium layers along the tetragonal c-axis. Neutron powder diffraction experiments, 57Fe M\\"ossbauer spectra, and density-functional theory calculations suggest that this behavior arises because a lattice instability resulting in alternating iron-osmium distances fine-tunes the balance of competing exchange interactions. Thus, Sr2FeOsO6 is an examp...

  4. /sup 87/Sr//sup 86/Sr ratios for basalt from Loihi Seamount, Hawaii

    Energy Technology Data Exchange (ETDEWEB)

    Lanphere, M. (Geological Survey, Menlo Park, CA (USA))

    1983-12-01

    /sup 87/Sr//sup 86/Sr ratios of 15 samples of basalt dredged from Loihi Seamount range from 0.70334 to 0.70368. The basalt types range from tholeiite to basanite in composition and can be divided into six groups on the basis of abundances of K/sub 2/O, Na/sub 2/O, Rb and Sr and /sup 87/Sr//sup 86/Sr ratio. The isotopic data require that the various basalt types be derived from source regions differing in Sr isotopic composition. The Loihi basalts may be produced by mixing of isotopically distinct sources, but the tholeiites and alkalic basalts from Loihi do not show a well-developed inverse trend between Rb/Sr and /sup 87/Sr//sup 86/Sr that is characteristic of the later stages of Hawaiian volcanoes such as Haleakala and Koolau.

  5. Lentiviral vector-mediated siRNA knockdown of SR-PSOX inhibits foam cell formation in vitro

    Institute of Scientific and Technical Information of China (English)

    Li ZHANG; Hou-jia LIU; Tie-jun LI; Yang YANG; Xian-ling GUO; Meng-chao WU; Yao-cheng RUI; Li-xin WEI

    2008-01-01

    Aim: To investigate the expression of scavenger receptor that binds phosphatidylserine and oxidized lipoprotein (SR-PSOX)/CXC chemokine ligand 16 (CXCL16) in the human monocyte-derived cell line THP-1, and the effect of lentiviral vectors for the stable delivery of SR-PSOX/CXCL16 short hairpin RNA on foam cell formation. Methods: A lentiviral expression vector containing enhanced green fluorescence protein (GFP) and SR-PSOX small interfering RNA (siRNA) (Lenti-SR-PSOXsi), or the control siRNA (Lenti-NC) gene was constructed. A human monocyte-derived cell line THP-1 was transfected with a different multiplicity of infection (MOI) of Lenti-SR-PSOXsi or Lenti-NC, and cultured to obtain stably-transfected THP-1KD and THP-1NC cells. After incubation with oxidatively-modified, low-density lipoprotein (Ox-LDL), the expression of SR-PSOX/CXCL16 mRNA was determined by real-time PCR. The expression of the SR-PSOX/CXCL16 protein was detected by flow cytometry analysis. The effect of Lenti-SR-PSOXsi on foam cell formation was assessed by Oil red O-stain analysis. Results: Ox-LDL increased the expres-sion of SR-PSOX/CXCL 16 mRNA in a time- and dose-dependent manner in THP-1 cells. Four days after transfection with Lenti-SR-PSOXsi (MOI: 100), the percent-age of GFP expression cells was over 89.3%. The expression of the SR-PSOX/ CXCL 16 mRNA and protein in THP- 1KD cells significantly decreased compared with the parent cells, even the THP-1KD cells stimulated with 40 mg/L Ox-LDL. Ox-LDL uptake experiments in THP-1- and THP- 1KD-derived macrophages indi-cated that SR-PSOX/CXCL16 deficiency decreased the development of macroph-age-derived foam cell formation. Conclusion: The above data showed that SR-PSOX siRNA delivered by using lentiviral vectors in THP-1 cells was a powerful tool for studying the effect of SR-PSOX, and decreased the expression of the SR-PSOX gene by inhibiting macrophage-derived foam cell formation.

  6. X-ray and neutron total scattering analysis of Hy·(Bi0.2Ca0.55Sr0.25)(Ag0.25Na0.75)Nb3O10·xH2O perovskite nanosheet booklets with stacking disorder

    Energy Technology Data Exchange (ETDEWEB)

    Metz, Peter; Koch, Robert; Cladek, Bernadette; Page, Katharine; Neuefeind, Joerg; Misture, Scott

    2016-05-23

    Ion-exchanged Aurivillius materials form perovskite nanosheet booklets wherein well-defined bi-periodic sheets, with ~11.5 Å thickness, exhibit extensive stacking disorder. The perovskite layer contents were defined initially using combined synchrotron X-ray and neutron Rietveld refinement of the parent Aurivillius structure. The structure of the subsequently ion-exchanged material, which is disordered in its stacking sequence, is analyzed using both pair distribution function (PDF) analysis and recursive method simulations of the scattered intensity. Combined X-ray and neutron PDF refinement of supercell stacking models demonstrates sensitivity of the PDF to both perpendicular and transverse stacking vector components. Further, hierarchical ensembles of stacking models weighted by a standard normal distribution are demonstrated to improve PDF fit over 1–25 Å. Recursive method simulations of the X-ray scattering profile demonstrate agreement between the real space stacking analysis and more conventional reciprocal space methods. The local structure of the perovskite sheet is demonstrated to relax only slightly from the Aurivillius structure after ion exchange.

  7. Origins of invasive piscivores determined from the strontium isotope ratio (87Sr/86Sr) of otoliths

    Science.gov (United States)

    Wolff, Brian A.; Johnson, Brett M.; Breton, Andre R.; Martinez, Patrick J.; Winkelman, Dana L.; Gillanders, Bronwyn

    2012-01-01

    We examined strontium isotope ratios (87Sr/86Sr) in fish otoliths to determine the origins of invasive piscivores in the Upper Colorado River Basin (UCRB, western USA). We examined 87Sr/86Sr from fishes in different reservoirs, as well as the temporal stability and interspecies variability of 87Sr/86Sr of fishes within reservoirs, determined if 87Sr/86Sr would be useful for "fingerprinting" reservoirs where invasive piscivores may have been escaping into riverine habitat of endangered fishes in the UCRB, and looked for evidence that such movement was occurring. Our results showed that in most cases 87Sr/86Sr was unique among reservoirs, overlapped among species in a given reservoir, and was temporally stable across years. We identified the likely reservoir of origin of river-caught fish in some cases, and we were also able to determine the year of possible escapement. The approach allowed us to precisely describe the 87Sr/86Sr fingerprint of reservoir fishes, trace likely origins of immigrant river fish, and exclude potential sources, enabling managers to focus control efforts more efficiently. Our results demonstrate the potential utility of 87Sr/86Sr as a site-specific and temporally stable marker for reservoir fish and its promise for tracking fish movements of invasive fishes in river-reservoir systems.

  8. Neutron signal transfer analysis

    CERN Document Server

    Pleinert, H; Lehmann, E

    1999-01-01

    A new method called neutron signal transfer analysis has been developed for quantitative determination of hydrogenous distributions from neutron radiographic measurements. The technique is based on a model which describes the detector signal obtained in the measurement as a result of the action of three different mechanisms expressed by signal transfer functions. The explicit forms of the signal transfer functions are determined by Monte Carlo computer simulations and contain only the distribution as a variable. Therefore an unknown distribution can be determined from the detector signal by recursive iteration. This technique provides a simple and efficient tool for analysis of this type while also taking into account complex effects due to the energy dependency of neutron interaction and single and multiple scattering. Therefore this method provides an efficient tool for precise quantitative analysis using neutron radiography, as for example quantitative determination of moisture distributions in porous buil...

  9. Temperature of neutron stars

    Science.gov (United States)

    Tsuruta, Sachiko

    2016-07-01

    We start with a brief introduction to the historical background in the early pioneering days when the first neutron star thermal evolution calculations predicted the presence of neutron stars hot enough to be observable. We then report on the first detection of neutron star temperatures by ROSAT X-ray satellite, which vindicated the earlier prediction of hot neutron stars. We proceed to present subsequent developments, both in theory and observation, up to today. We then discuss the current status and the future prospect, which will offer useful insight to the understanding of basic properties of ultra-high density matter beyond the nuclear density, such as the possible presence of such exotic particles as pion condensates.

  10. Decoherence Free Neutron Interferometry

    CERN Document Server

    Pushin, Dmitry A; Cory, David G

    2016-01-01

    Perfect single-crystal neutron interferometers are adversely sensitive to environmental disturbances, particularly mechanical vibrations. The sensitivity to vibrations results from the slow velocity of thermal neutrons and the long measurement time that are encountered in a typical experiment. Consequently, to achieve a good interference solutions for reducing vibration other than those normally used in optical experiments must be explored. Here we introduce a geometry for a neutron interferometer that is less sensitive to low-frequency vibrations. This design may be compared with both dynamical decoupling methods and decoherence-free subspaces that are described in quantum information processing. By removing the need for bulky vibration isolation setups, this design will make it easier to adopt neutron interferometry to a wide range of applications and increase its sensitivity.

  11. Neutron Stars Recent Developments

    CERN Document Server

    Heiselberg, H

    1999-01-01

    Recent developments in neutron star theory and observation are discussed. Based on modern nucleon-nucleon potentials more reliable equations of state for dense nuclear matter have been constructed. Furthermore, phase transitions such as pion, kaon and hyperon condensation, superfluidity and quark matter can occur in cores of neutron stars. Specifically, the nuclear to quark matter phase transition and its mixed phases with intriguing structures is treated. Rotating neutron stars with and without phase transitions are discussed and compared to observed masses, radii and glitches. The observations of possible heavy $\\sim 2M_\\odot$ neutron stars in X-ray binaries and QPO's require relatively stiff equation of states and restrict strong phase transitions to occur at very high nuclear densities only.

  12. The intense neutron generator

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, W.B

    1966-07-01

    The presentation discusses both the economic and research contexts that would be served by producing neutrons in gram quantities at high intensities by electrical means without uranium-235. The revenue from producing radioisotopes is attractive. The array of techniques introduced by the multipurpose 65 megawatt Intense Neutron Generator project includes liquid metal cooling, superconducting magnets for beam bending and focussing, super-conductors for low-loss high-power radiofrequency systems, efficient devices for producing radiofrequency power, plasma physics developments for producing and accelerating hydrogen, ions at high intensity that are still far out from established practice, a multimegawatt high voltage D.C. generating machine that could have several applications. The research fields served relate principally to materials science through neutron-phonon and other quantum interactions as well as through neutron diffraction. Nuclear physics is served through {mu}-, {pi}- and K-meson production. Isotope production enters many fields of applied research. (author)

  13. Critical spin dynamics of the 2D quantum Heisenberg antiferromagnets Sr2CuO2Cl2 and Sr2Cu3O4Cl2.

    Science.gov (United States)

    Kim, Y J; Birgeneau, R J; Chou, F C; Erwin, R W; Kastner, M A

    2001-04-02

    We report a neutron scattering study of the long-wavelength dynamic spin correlations in the model two-dimensional S = 1/2 square lattice Heisenberg antiferromagnets Sr2CuO2Cl2 and Sr2Cu3O4Cl2. The characteristic energy scale, omega(0)(T/J), is determined by measuring the quasielastic peak width in the paramagnetic phase over a wide range of temperature ( 0.2 less similarT/J less similar0.7). The obtained values for omega(0)(T/J) agree quantitatively between the two compounds and also with values deduced from quantum Monte Carlo simulations. The combined data show scaling behavior, omega approximately xi(-z), over the entire temperature range with z = 1.0(1), in agreement with dynamic scaling theory.

  14. Magnetic-Field-Induced Soft-Mode Quantum Phase Transition in the High-Temperature Superconductor La1.855Sr0.145CuO4

    DEFF Research Database (Denmark)

    Chang, J.; Christensen, Niels Bech; Niedermayer, C.

    2009-01-01

    Inelastic neutron-scattering experiments on the high-temperature superconductor La1.855Sr0.145CuO4 reveal a magnetic excitation gap Delta that decreases continuously upon application of a magnetic field perpendicular to the CuO2 planes. The gap vanishes at the critical field required to induce long...

  15. The temperature evolution of the out-of-plane correlation lengths of charge-stripe ordered La1.725Sr0.275NiO4

    DEFF Research Database (Denmark)

    Freeman, P.G.; Christensen, Niels Bech; Prabhakaran, D.;

    2010-01-01

    The temperature dependence of the magnetic order of stripe-ordered La1.725Sr0.275NiO4 is investigated by neutron diffraction. Upon cooling, the widths of the magnetic Bragg peaks are observed to broaden. The degree of broadening is found to be very different for l = odd-integer and l = even-integ...

  16. Structure and conductivity of layered oxides (Ba,Sr){sub n+1}(Sn,Sb){sub n}O{sub 3n+1}

    Energy Technology Data Exchange (ETDEWEB)

    Green, M.A. [Royal Institution of Great Britain, London (United Kingdom); Prassides, K. [Royal Institution of Great Britain, London (United Kingdom)]|[School of Chemistry and Molecular Science, Sussex Univ., Brighton (United Kingdom); Day, P. [Royal Institution of Great Britain, London (United Kingdom); Stalick, J.K. [Research Radiation Div., National Inst. of Standards and Technology, Gaithersburg, MD (United States)

    1995-04-01

    Structures of various members of the Ruddlesdon-Popper homologous series, (Ba,Sr){sub n+1}(Sn,Sb){sub n}O{sub 3n+1}, solved by Rietveld refinement of powder neutron diffraction data are summarised. Predictions of band gaps are made on the basis of extended Hueckel calculations. (orig.)

  17. Magnetic-field-induced spin excitations and renormalized spin gap of the underdoped La1895Sr0105CuO4 superconductor

    DEFF Research Database (Denmark)

    Chang, J.; Schnyder, A.P.; Gilardi, R.

    2007-01-01

    High-resolution neutron inelastic scattering experiments in applied magnetic fields have been performed on La1.895Sr0.105CuO4 (LSCO). In zero field, the temperature dependence of the low-energy peak intensity at the incommensurate momentum transfer Q(IC)=(0.5,0.5 +/-delta,0),(0.5 +/-delta,0.5,0) ...

  18. Field-induced interplanar magnetic correlations in the high-temperature superconductor La1.88Sr0.12CuO4

    DEFF Research Database (Denmark)

    Rømer, A. T.; Jensen, P.; Jacobsen, H.

    2015-01-01

    We present neutron-scattering studies of the interplanar magnetic correlations in the high-temperature superconductor La1.88Sr0.12CuO4 (Tc=27 K). The correlations are studied both in a magnetic field applied perpendicular to the CuO2 planes, and in zero field under different cooling conditions. We...

  19. Nature of the magnetic order in the charge-ordered cuprate La1.48Nd0.4Sr0.12CuO4

    DEFF Research Database (Denmark)

    Christensen, Niels Bech; Rønnow, H.M.; Mesot, J.;

    2007-01-01

    Using polarized neutron scattering we establish that the magnetic order in La1.48Nd0.4Sr0.12CuO4 is either (i) one dimensionally modulated and collinear, consistent with the stripe model or (ii) two dimensionally modulated with a novel noncollinear structure. The measurements rule out a number...

  20. Thermoelastic and structural properties of ionically conducting cerate perovskites: (II) SrCeO3 between 1273 K and 1723 K

    DEFF Research Database (Denmark)

    Knight, Kevin S.; Haynes, Richard; Bonanos, Nikolaos

    2015-01-01

    The temperature dependence of the crystal structure and the thermoelastic properties of SrCeO3 have been determined from Rietveld refinement of high resolution, neutron time-of-flight powder diffraction data collected in 5 K intervals between 1273 K and 1723 K. No evidence was found for critical ...

  1. Introduction to neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, W.E. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1996-11-01

    We give here an introduction to the theoretical principles of neutron scattering. The relationship between scattering- and correlation-functions is particularly emphasized. Within the framework of linear response theory (justified by the weakness of the basic interaction) the relation between fluctuation and dissipation is discussed. This general framework explains the particular power of neutron scattering as an experimental method. (author) 4 figs., 4 refs.

  2. Neutron scattering in dimers

    DEFF Research Database (Denmark)

    Gudel, H. U.; Furrer, A.; Kjems, Jørgen

    1986-01-01

    Insulating compounds containing dimers of transition metal and rare earth ions have been studied by inelastic neutron scattering (INS). Energy splittings can be directly determined, and the corresponding parameters are easily extracted from the experimental data. The intensities of dimer excitati......Insulating compounds containing dimers of transition metal and rare earth ions have been studied by inelastic neutron scattering (INS). Energy splittings can be directly determined, and the corresponding parameters are easily extracted from the experimental data. The intensities of dimer...

  3. Pulsed spallation Neutron Sources

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter, J.M. [Argonne National Lab., IL (United States)

    1994-12-31

    This paper reviews the early history of pulsed spallation neutron source development at Argonne and provides an overview of existing sources world wide. A number of proposals for machines more powerful than currently exist are under development, which are briefly described. The author reviews the status of the Intense Pulsed Neutron Source, its instrumentation, and its user program, and provides a few examples of applications in fundamental condensed matter physics, materials science and technology.

  4. SrRuO3 thin films grown on MgO substrates at different oxygen partial pressures

    KAUST Repository

    Zou, Bin

    2013-01-08

    A comprehensive study of SrRuO3 thin films growth on (001) MgO substrates by pulsed laser deposition in a wide oxygen pressure range from 10 to 300 mTorr was carried out. The experimental results showed a correlation between the lattice constants, resistivity, and oxygen partial pressures used. Ru deficiency detected only in films deposited at lower oxygen pressures (<50 mTorr), resulted in an elongation of the in-plane and out-of-plane lattice constants and an increase in the film resistivity. When deposited with oxygen partial pressure of 50 mTorr, SrRuO3 films had lattice parameters matching those of bulk SrRuO3 material and exhibited room temperature resistivity of 320 μΩ·cm. The resistivity of SrRuO 3/MgO films decreased with increasing oxygen partial pressure. Copyright © 2013 Materials Research Society.

  5. Neutron scattering in Australia

    Energy Technology Data Exchange (ETDEWEB)

    Knott, R.B. [Australian Nuclear Science and Technology Organisation, Menai (Australia)

    1994-12-31

    Neutron scattering techniques have been part of the Australian scientific research community for the past three decades. The High Flux Australian Reactor (HIFAR) is a multi-use facility of modest performance that provides the only neutron source in the country suitable for neutron scattering. The limitations of HIFAR have been recognized and recently a Government initiated inquiry sought to evaluate the future needs of a neutron source. In essence, the inquiry suggested that a delay of several years would enable a number of key issues to be resolved, and therefore a more appropriate decision made. In the meantime, use of the present source is being optimized, and where necessary research is being undertaken at major overseas neutron facilities either on a formal or informal basis. Australia has, at present, a formal agreement with the Rutherford Appleton Laboratory (UK) for access to the spallation source ISIS. Various aspects of neutron scattering have been implemented on HIFAR, including investigations of the structure of biological relevant molecules. One aspect of these investigations will be presented. Preliminary results from a study of the interaction of the immunosuppressant drug, cyclosporin-A, with reconstituted membranes suggest that the hydrophobic drug interdigitated with lipid chains.

  6. Coded source neutron imaging

    Energy Technology Data Exchange (ETDEWEB)

    Bingham, Philip R [ORNL; Santos-Villalobos, Hector J [ORNL

    2011-01-01

    Coded aperture techniques have been applied to neutron radiography to address limitations in neutron flux and resolution of neutron detectors in a system labeled coded source imaging (CSI). By coding the neutron source, a magnified imaging system is designed with small spot size aperture holes (10 and 100 m) for improved resolution beyond the detector limits and with many holes in the aperture (50% open) to account for flux losses due to the small pinhole size. An introduction to neutron radiography and coded aperture imaging is presented. A system design is developed for a CSI system with a development of equations for limitations on the system based on the coded image requirements and the neutron source characteristics of size and divergence. Simulation has been applied to the design using McStas to provide qualitative measures of performance with simulations of pinhole array objects followed by a quantitative measure through simulation of a tilted edge and calculation of the modulation transfer function (MTF) from the line spread function. MTF results for both 100um and 10um aperture hole diameters show resolutions matching the hole diameters.

  7. Coded source neutron imaging

    Science.gov (United States)

    Bingham, Philip; Santos-Villalobos, Hector; Tobin, Ken

    2011-03-01

    Coded aperture techniques have been applied to neutron radiography to address limitations in neutron flux and resolution of neutron detectors in a system labeled coded source imaging (CSI). By coding the neutron source, a magnified imaging system is designed with small spot size aperture holes (10 and 100μm) for improved resolution beyond the detector limits and with many holes in the aperture (50% open) to account for flux losses due to the small pinhole size. An introduction to neutron radiography and coded aperture imaging is presented. A system design is developed for a CSI system with a development of equations for limitations on the system based on the coded image requirements and the neutron source characteristics of size and divergence. Simulation has been applied to the design using McStas to provide qualitative measures of performance with simulations of pinhole array objects followed by a quantitative measure through simulation of a tilted edge and calculation of the modulation transfer function (MTF) from the line spread function. MTF results for both 100μm and 10μm aperture hole diameters show resolutions matching the hole diameters.

  8. Neutron Nucleic Acid Crystallography.

    Science.gov (United States)

    Chatake, Toshiyuki

    2016-01-01

    The hydration shells surrounding nucleic acids and hydrogen-bonding networks involving water molecules and nucleic acids are essential interactions for the structural stability and function of nucleic acids. Water molecules in the hydration shells influence various conformations of DNA and RNA by specific hydrogen-bonding networks, which often contribute to the chemical reactivity and molecular recognition of nucleic acids. However, X-ray crystallography could not provide a complete description of structural information with respect to hydrogen bonds. Indeed, X-ray crystallography is a powerful tool for determining the locations of water molecules, i.e., the location of the oxygen atom of H2O; however, it is very difficult to determine the orientation of the water molecules, i.e., the orientation of the two hydrogen atoms of H2O, because X-ray scattering from the hydrogen atom is very small.Neutron crystallography is a specialized tool for determining the positions of hydrogen atoms. Neutrons are not diffracted by electrons, but are diffracted by atomic nuclei; accordingly, neutron scattering lengths of hydrogen and its isotopes are comparable to those of non-hydrogen atoms. Therefore, neutron crystallography can determine both of the locations and orientations of water molecules. This chapter describes the current status of neutron nucleic acid crystallographic research as well as the basic principles of neutron diffraction experiments performed on nucleic acid crystals: materials, crystallization, diffraction experiments, and structure determination.

  9. Nutritional iron deficiency

    NARCIS (Netherlands)

    Zimmermann, M.B.; Hurrell, R.F.

    2007-01-01

    Iron deficiency is one of the leading risk factors for disability and death worldwide, affecting an estimated 2 billion people. Nutritional iron deficiency arises when physiological requirements cannot be met by iron absorption from diet. Dietary iron bioavailability is low in populations consuming

  10. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... Blood Tests Blood Transfusion Restless Legs Syndrome Send a link to NHLBI to someone by E-MAIL | ... Iron-Deficiency Anemia? Español Iron-deficiency anemia is a common, easily treated condition that occurs if you ...

  11. Iron deficiency anemia

    Science.gov (United States)

    Anemia - iron deficiency ... iron from old red blood cells. Iron deficiency anemia develops when your body's iron stores run low. ... You may have no symptoms if the anemia is mild. Most of the time, ... slowly. Symptoms may include: Feeling weak or tired more often ...

  12. Muscle phosphorylase kinase deficiency

    DEFF Research Database (Denmark)

    Preisler, N; Orngreen, M C; Echaniz-Laguna, A;

    2012-01-01

    To examine metabolism during exercise in 2 patients with muscle phosphorylase kinase (PHK) deficiency and to further define the phenotype of this rare glycogen storage disease (GSD).......To examine metabolism during exercise in 2 patients with muscle phosphorylase kinase (PHK) deficiency and to further define the phenotype of this rare glycogen storage disease (GSD)....

  13. Growth Hormone Deficiency

    Directory of Open Access Journals (Sweden)

    Ömer Tarım

    2010-05-01

    Full Text Available Growth hormone deficiency is the most promising entity in terms of response to therapy among the treatable causes of growth retardation. It may be due to genetic or acquired causes. It may be isolated or a part of multiple hormone deficiencies. Diagnostic criteria and therefore treatment indications are still disputed. (Journal of Current Pediatrics 2010; 8: 36-8

  14. Nutritional iron deficiency

    NARCIS (Netherlands)

    Zimmermann, M.B.; Hurrell, R.F.

    2007-01-01

    Iron deficiency is one of the leading risk factors for disability and death worldwide, affecting an estimated 2 billion people. Nutritional iron deficiency arises when physiological requirements cannot be met by iron absorption from diet. Dietary iron bioavailability is low in populations consuming

  15. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... periods. By following her treatment plan and making smart lifestyle choices, Susan continues to feel better and see the benefits of treatment. For more information about living with and managing iron-deficiency anemia, go to the Health Topics Iron-Deficiency Anemia article. Updated: March 26, ...

  16. Iron induced nickel deficiency

    Science.gov (United States)

    It is increasingly apparent that economic loss due to nickel (Ni) deficiency likely occurs in horticultural and agronomic crops. While most soils contain sufficient Ni to meet crop requirements, situations of Ni deficiency can arise due to antagonistic interactions with other metals. This study asse...

  17. Iron deficiency in childhood

    NARCIS (Netherlands)

    Uijterschout, L.

    2015-01-01

    Iron deficiency (ID) is the most common micronutrient deficiency in the world. Iron is involved in oxygen transport, energy metabolism, immune response, and plays an important role in brain development. In infancy, ID is associated with adverse effects on cognitive, motor, and behavioral development

  18. Deficiently Extremal Gorenstein Algebras

    Indian Academy of Sciences (India)

    Pavinder Singh

    2011-08-01

    The aim of this article is to study the homological properties of deficiently extremal Gorenstein algebras. We prove that if / is an odd deficiently extremal Gorenstein algebra with pure minimal free resolution, then the codimension of / must be odd. As an application, the structure of pure minimal free resolution of a nearly extremal Gorenstein algebra is obtained.

  19. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... Blood Tests Blood Transfusion Restless Legs Syndrome Send a link to NHLBI to someone by E-MAIL | ... Iron-Deficiency Anemia? Español Iron-deficiency anemia is a common, easily treated condition that occurs if you ...

  20. Iron deficiency in childhood

    NARCIS (Netherlands)

    Uijterschout, L.

    2015-01-01

    Iron deficiency (ID) is the most common micronutrient deficiency in the world. Iron is involved in oxygen transport, energy metabolism, immune response, and plays an important role in brain development. In infancy, ID is associated with adverse effects on cognitive, motor, and behavioral development

  1. MAGNETIC NEUTRON SCATTERING

    Energy Technology Data Exchange (ETDEWEB)

    ZALIZNYAK,I.A.; LEE,S.H.

    2004-07-30

    Much of our understanding of the atomic-scale magnetic structure and the dynamical properties of solids and liquids was gained from neutron-scattering studies. Elastic and inelastic neutron spectroscopy provided physicists with an unprecedented, detailed access to spin structures, magnetic-excitation spectra, soft-modes and critical dynamics at magnetic-phase transitions, which is unrivaled by other experimental techniques. Because the neutron has no electric charge, it is an ideal weakly interacting and highly penetrating probe of matter's inner structure and dynamics. Unlike techniques using photon electric fields or charged particles (e.g., electrons, muons) that significantly modify the local electronic environment, neutron spectroscopy allows determination of a material's intrinsic, unperturbed physical properties. The method is not sensitive to extraneous charges, electric fields, and the imperfection of surface layers. Because the neutron is a highly penetrating and non-destructive probe, neutron spectroscopy can probe the microscopic properties of bulk materials (not just their surface layers) and study samples embedded in complex environments, such as cryostats, magnets, and pressure cells, which are essential for understanding the physical origins of magnetic phenomena. Neutron scattering is arguably the most powerful and versatile experimental tool for studying the microscopic properties of the magnetic materials. The magnitude of the cross-section of the neutron magnetic scattering is similar to the cross-section of nuclear scattering by short-range nuclear forces, and is large enough to provide measurable scattering by the ordered magnetic structures and electron spin fluctuations. In the half-a-century or so that has passed since neutron beams with sufficient intensity for scattering applications became available with the advent of the nuclear reactors, they have became indispensable tools for studying a variety of important areas of modern

  2. MAGNETIC NEUTRON SCATTERING

    Energy Technology Data Exchange (ETDEWEB)

    ZALIZNYAK,I.A.; LEE,S.H.

    2004-07-30

    Much of our understanding of the atomic-scale magnetic structure and the dynamical properties of solids and liquids was gained from neutron-scattering studies. Elastic and inelastic neutron spectroscopy provided physicists with an unprecedented, detailed access to spin structures, magnetic-excitation spectra, soft-modes and critical dynamics at magnetic-phase transitions, which is unrivaled by other experimental techniques. Because the neutron has no electric charge, it is an ideal weakly interacting and highly penetrating probe of matter's inner structure and dynamics. Unlike techniques using photon electric fields or charged particles (e.g., electrons, muons) that significantly modify the local electronic environment, neutron spectroscopy allows determination of a material's intrinsic, unperturbed physical properties. The method is not sensitive to extraneous charges, electric fields, and the imperfection of surface layers. Because the neutron is a highly penetrating and non-destructive probe, neutron spectroscopy can probe the microscopic properties of bulk materials (not just their surface layers) and study samples embedded in complex environments, such as cryostats, magnets, and pressure cells, which are essential for understanding the physical origins of magnetic phenomena. Neutron scattering is arguably the most powerful and versatile experimental tool for studying the microscopic properties of the magnetic materials. The magnitude of the cross-section of the neutron magnetic scattering is similar to the cross-section of nuclear scattering by short-range nuclear forces, and is large enough to provide measurable scattering by the ordered magnetic structures and electron spin fluctuations. In the half-a-century or so that has passed since neutron beams with sufficient intensity for scattering applications became available with the advent of the nuclear reactors, they have became indispensable tools for studying a variety of important areas of modern

  3. Fundamental neutron physics at LANSCE

    Energy Technology Data Exchange (ETDEWEB)

    Greene, G.

    1995-10-01

    Modern neutron sources and science share a common origin in mid-20th-century scientific investigations concerned with the study of the fundamental interactions between elementary particles. Since the time of that common origin, neutron science and the study of elementary particles have evolved into quite disparate disciplines. The neutron became recognized as a powerful tool for studying condensed matter with modern neutron sources being primarily used (and justified) as tools for neutron scattering and materials science research. The study of elementary particles has, of course, led to the development of rather different tools and is now dominated by activities performed at extremely high energies. Notwithstanding this trend, the study of fundamental interactions using neutrons has continued and remains a vigorous activity at many contemporary neutron sources. This research, like neutron scattering research, has benefited enormously by the development of modern high-flux neutron facilities. Future sources, particularly high-power spallation sources, offer exciting possibilities for continuing this research.

  4. Radiography with polarised neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, Michael L.

    2010-08-20

    In this thesis I present a new technique for the spatially resolved investigation of the magnetic properties of bulk samples. Standard one dimensional neutron depolarisation analysis is combined with neutron radiography to a method we call Neutron Depolarisation Imaging (NDI). The experimental setup which was installed at the neutron radiography beam line ANTARES at FRM II consists of a double crystal monochromator, neutron polariser, spin flipper, polarisation analyser and a position sensitive CCD detector. A comprehensive discussion of the requirements for these components is given and the limitations of the method are shown. The maximum spatial resolution which can be achieved with a neutron radiography setup is determined by the collimation of the neutron beam and the distance between sample and detector. Different types of polarisers have been tested and their advantages and disadvantages are discussed. A double crystal monochromator and a new type of polariser employing polarising neutron supermirrors based on the principle of an optical periscope were developed and tested during this work. Furthermore, NDI measurements on various samples of the weakly ferromagnetic materials Pd{sub 1-x}Ni{sub x} and Ni{sub 3}Al are presented. Neutron depolarisation radiography and tomography measurements were conducted with a spatial resolution as high as 0.3 mm on Pd{sub 1-x}Ni{sub x} and Ni{sub 3}Al samples. The feasibility of NDI experiments under hydrostatic pressures up to 10 kbar was shown on a sample of Ni{sub 3}Al using a modified Cu:Be clamp cell. A decrease of the ordering temperature by 2 K under hydrostatic pressure was determined from the NDI measurements and shows the potential of the method for further high pressure experiments. Additionally a method was developed which in principle allows to obtain the intrinsic dependence of the ordering temperature T{sub C} on the ordered moment Ms from NDI measurements on inhomogeneous samples containing regions with

  5. Enhancing spin state phase separation by strontium addition in the Y (Ba{sub 1-x}Sr{sub x})Co{sub 2}O{sub 5.5} layered cobaltite

    Energy Technology Data Exchange (ETDEWEB)

    Aurelio, G; Curiale, J; Sanchez, R D [Consejo Nacional de Investigaciones Cientificas y Tecnicas, Centro Atomico Bariloche-Comision Nacional de Energia Atomica, Avenida Bustillo 9500, 8400 San Carlos de Bariloche, RN (Argentina); Cuello, G J, E-mail: gaurelio@cab.cnea.gov.a [Department of Applied Physics II, Ikerbasque, UPV/EHU, E-48080 Bilbao (Spain)

    2009-08-12

    In this paper we present a neutron diffraction study of the effects of replacing Ba with smaller Sr cations in the layered cobaltite YBaCo{sub 2}O{sub 5+{delta}} for {delta}{approx}0.5. Neutron thermodiffractograms are reported in the temperature range 20 K<=T<=300 K, as well as high-resolution neutron diffraction experiments at selected temperatures. The systematic refinement of the series of samples with Sr substituting at the Ba site permits the understanding of the complex magnetic behaviour of this system, and reinforces a two-phase scenario for the parent compound. We have found that Sr addition destabilizes the ferrimagnetic spin state ordered phase, as well as the '122' order characteristic of cobaltites with delta = 0.5, favouring instead a tetragonal and less ordered structure.

  6. Neutron-Induced Failures in Semiconductor Devices

    Energy Technology Data Exchange (ETDEWEB)

    Wender, Stephen Arthur [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-04-06

    This slide presentation explores single event effect, environmental neutron flux, system response, the Los Alamos Neutron Science Center (LANSCE) neutron testing facility, examples of SEE measurements, and recent interest in thermal neutrons.

  7. Synthesis, structure, and magnetic properties of novel B-site ordered double perovskites, SrLaMReO6 (M = Mg, Mn, Co and Ni).

    Science.gov (United States)

    Thompson, Corey M; Chi, Lisheng; Hayes, John R; Hallas, Alannah M; Wilson, Murray N; Munsie, Timothy J S; Swainson, Ian P; Grosvenor, Andrew P; Luke, Graeme M; Greedan, John E

    2015-06-21

    Four new double perovskites, SrLaMReO(6) (M = Mg, Mn, Co, Ni) in which Re(5+) (5d(2)) is present, were prepared via conventional solid state reactions and characterized by X-ray and neutron powder diffraction, XANES, SQUID magnetometry, and muon spin relaxation (μSR). Synchrotron X-ray and neutron diffraction experiments confirmed that all compounds crystallize in the monoclinic P2(1)/n structure type, which consists of alternately corner-shared octahedra of MO(6) and ReO(6). Rietveld refinement results indicated anti-site mixing of less than 7% on the M/Re sites. Bond valence sum calculations (BVS) suggest all M and Re ions are 2+ and 5+, respectively, and for the Mn-containing phase this is also supported by XANES measurements. All of the materials are paramagnetic at room-temperature and their Curie-Weiss temperatures are positive (except for Mg) indicating net ferromagnetic interactions. No evidence for long-range magnetic order is evident in the dc magnetic susceptibility and μSR measurements for SrLaMgReO(6) to 2 K. The Mn-phase shows long-range order at T(C) = 190 K and neutron diffraction revealed a ferromagnetic structure with a refined net moment of ∼3.7μ(B). Both Co- and Ni-containing phases exhibit spin glass behavior at T(G) = 23 and 30 K, respectively, which is supported by neutron diffraction and a.c. susceptibility data. The structure and physical properties of these four new rhenium based ordered double perovskites are compared to the closely related "pillared perovskites", La(5)Re(3)MO(16), the isoelectronic Os(6+) (5d(2)) double perovskite Sr(2)CoOsO(6), and the Re(6+) (5d(1)) double perovskites, Sr(2)MReO(6), (M = Mg, Ca, Mn, Co, Ni).

  8. Neutron drip transition in accreting and nonaccreting neutron star crusts

    CERN Document Server

    Chamel, N; Zdunik, J L; Haensel, P

    2015-01-01

    The neutron-drip transition in the dense matter constituting the interior of neutron stars generally refers to the appearance of unbound neutrons as the matter density reaches some threshold density $\\rho_\\textrm{drip}$. This transition has been mainly studied under the cold catalyzed matter hypothesis. However, this assumption is unrealistic for accreting neutron stars. After examining the physical processes that are thought to be allowed in both accreting and nonaccreting neutron stars, suitable conditions for the onset of neutron drip are derived and general analytical expressions for the neutron drip density and pressure are obtained. Moreover, we show that the neutron-drip transition occurs at lower density and pressure than those predicted within the mean-nucleus approximation. This transition is studied numerically for various initial composition of the ashes from X-ray bursts and superbursts using microscopic nuclear mass models.

  9. Neutron activation analysis of medullar and cortical bone tissues from animals; Analise por ativacao com neutrons de tecidos osseos medular e cortical de animais

    Energy Technology Data Exchange (ETDEWEB)

    Takata, Marcelo Kazuo; Saiki, Mitiko [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Supervisao de Radioquimica

    2000-07-01

    In this work, neutron activation analysis was applied in the determination of the elements Ba, Br, Ca, Cl, Cr, Fe, K, Mg, Mn, Na, P, Rb, Sb, Sc, Sr and Zn present in animal bone tissues. The obtained results indicated a significant difference between the elemental concentrations present in medullar and cortical tissues. The results obtained for bone tissues from distinct animal species were also different. (author)

  10. Measurement of Cosmic-ray Muons and Muon-induced Neutrons in the Aberdeen Tunnel Underground Laboratory

    CERN Document Server

    Blyth, S C; Chen, X C; Chu, M C; Cui, K X; Hahn, R L; Ho, T H; Hsiung, Y B; Hu, B Z; Kwan, K K; Kwok, M W; Kwok, T; Lau, Y P; Leung, J K C; Leung, K Y; Lin, G L; Lin, Y C; Luk, K B; Luk, W H; Ngai, H Y; Ngan, S Y; Pun, C S J; Shih, K; Tam, Y H; Tsang, R H M; Wang, C H; Wong, C M; Wong, H L; Wong, K K; Yeh, M; Zhang, B J

    2015-01-01

    We measured the muon flux and the production rate of muon-induced neutrons at a depth of 611 meters water equivalent. Our apparatus comprises of three layers of crossed plastic scintillator hodoscopes for tracking the incident cosmic-ray muons, and 760 L of gadolinium-doped liquid scintillator for both neutron production and detection targets. The vertical muon intensity was measured to be $I_{\\mu}$ = (5.7 $\\pm$ 0.6) $\\times$ 10$^{-6}$ cm$^{-2}$ s$^{-1}$ sr$^{-1}$. The muon-induced neutron yield in the liquid scintillator was determined to be $Y_{n}$ = (1.19 $\\pm$ 0.08(stat.) $\\pm$ 0.21(syst.)) $\\times$ 10$^{-4}$ neutrons / ($\\mu$ g cm$^{-2}$). A fitting to recently measured neutron yields at different depths gave a muon energy dependence of $\\left\\langle E_{\\mu} \\right\\rangle^{0.76 \\pm 0.03}$ for scintillator targets.

  11. Laser Spectroscopy Study on the Neutron-Rich and Neutron-Deficient Te Isotopes

    CERN Multimedia

    2002-01-01

    We propose to perform laser spectroscopy measurements on the Te isotopes. This will give access to fundamental properties of the ground and rather long-lived isomeric states such as the change in the mean square charge radius ($\\delta\\langle$r$^2_c\\rangle$) and the nuclear moments. For these medium-mass isotopes, at this moment the optical resolution obtained with RILIS is not high enough to perform isotope shift measurements. Thus we will use the COMPLIS experimental setup which allows Resonant Ionization Spectroscopy (RIS) on laser desorbed atoms. The 5p$^{4}$ $^{3}$P$_{2} \\rightarrow$ 5p$^{3}$ 6s $^{3}$S$_{1}$ and 5p$^{4}$ $^{3}$P$_{2} \\rightarrow$ 5p$^{3}$ 6s $^{5}$S$_{2}$ optical transitions have been used to perform, on the stable Te isotopes, the tests required by the INTC committee. For this purpose stable-ion sources have been built and Te isotopes have been delivered as stable beams by the injector coupled to the COMPLIS setup. ISOLDE offers the opportunity for studying the Te isotope series over a ...

  12. Experimental tests of an advanced proton-to-neutron converter at ISOLDE-CERN

    CERN Document Server

    Gottberg, A; Luis, R; Ramos, J P; Seiffert, C; Cimmino, S; Marzari, S; Crepieux, B; Manea, V; Wolf, R N; Wienholtz, F; Kreim, S; Fedosseev, V N; Marsh, B A; Rothe, S; Vaz, P; Marques, J G; Stora, T

    2014-01-01

    The suppression of isobaric contaminations is of growing importance for many scientific programs using radioactive isotopes produced at isotope separation on-line (ISOL) facilities, such as ISOLDE-CERN. A solid tungsten proton-to-neutron converter has been used for ten years to produce neutron-rich fission fragments from an UC x target while suppressing the production of neutron-deficient isobaric contaminants. The remaining contamination is mainly produced by primary protons that are scattered by the heavy neutron converter and finally impinge on the UC x target itself. Therefore, the knowledge of the energy-dependant cross-sections of proton and neutron induced fission events is crucial in order to evaluate future converter concepts.

  13. Spin-Dependent Electroresistance Behaviour of Nd0.67Sr0.33MnO3-δ(0≤δ≤0.20)

    Institute of Scientific and Technical Information of China (English)

    Zhou Zhihui; Yang Changping; Deng Heng; Yang Fujun

    2007-01-01

    Oxygen deficient Nd0.67Sr0.33MnO3-δ ceramic samples were prepared using conventional ceramic technology. A colossal electroresistance (CER) effect was found in Nd0.67Sr0.33MnO3-δ series. The electrical transport is magnetically coupled and spin-dependent over grain or phase boundaries. Electrical-field-induced changes of the spin array orientations inside of and between the magnetic domains by grain or phase boundaries have to be concluded for the strong electroresistive effect in Nd0.67Sr0.33MnO3-δ series.

  14. Shape coexistence in neutron-rich strontium isotopes at N = 60

    Science.gov (United States)

    Clément, E.; Zielińska, M.

    2017-08-01

    The structure of neutron-rich {}{96,98}Sr nuclei was investigated by low-energy Coulomb excitation of radioactive beams at the REX-ISOLDE facility, CERN, with the MINIBALL spectrometer. The results support the scenario of a shape transition at N = 60, giving rise to the coexistence of a highly deformed prolate and a spherical configuration in 98Sr with low configuration mixing. They are discussed in the context of systematics of quadrupole moments and transition probabilities in the N = 60 region.

  15. Simulation of a complete inelastic neutron scattering experiment

    CERN Document Server

    Edwards, H; Nielsen, K; Skaarup, P; Lake, B

    2002-01-01

    A simulation of an inelastic neutron scattering experiment on the high-temperature superconductor La sub 2 sub - sub x Sr sub x CuO sub 4 is presented. The complete experiment, including sample, is simulated using an interface between the experiment control program and the simulation software package (McStas) and is compared with the experimental data. Simulating the entire experiment is an attractive alternative to the usual method of convoluting the model cross section with the resolution function, especially if the resolution function is nontrivial. (orig.)

  16. Experiences with the determination of Sr-89 and Sr-90 using fast methods; Erfahrungen bei der Bestimmung von {sup 89}Sr und {sup 90}Sr mittels Schnellmethoden

    Energy Technology Data Exchange (ETDEWEB)

    Kowalik, C.; Fueger, J. [Thueringer Landesanstalt fuer Umwelt und Geologie, Jena (Germany). Landesmessstelle fuer Umweltradioaktivaet

    2014-01-20

    Quick methods of the measurement of {sup 89}Sr and {sup 90}Sr have a great importance in the supervision of the environmental radioactivity. It is necessary to receive in short time dependable analytical data to be able to carry out suitable assessments or to give recommendations. The aim of the investigations was to be guaranteed the demands for these methods (test preparation, measurement and evaluation). The use of the solid phase extraction by means of commercial Sr Resin trademark columns (4.4' (5')-Di-tert-butylcyclohexanol-18-kronen-6-aether) (Triskem) to the radiochemical separation of the Sr isotopes was suitable. The measurements occurred to the FHT 770 T12 - Multi Low Level Alpha/Beta Sample Counter (Thermo Scientific). The results contain the summary activities of all available Sr isotopes, as for example {sup 89}Sr and {sup 90}Sr. The calculations of the single activities occur about the mathematical algorithm of the linear development on the basis of the works of G. Kanisch. The first results show, this method is suitable for the analysis of {sup 89}Sr and {sup 90}Sr and is used therefore in future in Thuringia.

  17. Single crystal growth of Sr{sub 2}TiMnO{sub 6} by optical floating zone technique

    Energy Technology Data Exchange (ETDEWEB)

    Murugesan, G.; Kalainathan, S. [Centre for Crystal Growth, School of Advanced Sciences, VIT University, Vellore 632 014, Tamil Nadu (India); Nithya, R. [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu (India); Das, Amitabh [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai – 400085 (India)

    2016-05-23

    Single crystals of Sr{sub 2}TiMnO{sub 6} were grown by optical floating zone technique. Powder X-ray diffraction studies confirmed the single phase nature of the grown crystal. Laue diffraction studies proved the quality of the grown crystal. Neutron diffraction showed no magnetic ordering down to 6 K. Impedance studies showed temperature dependant relaxation which is due to the presence of oxygen vacancies in the grown crystal.

  18. Influence of the neutron transport tube on neutron resonance densitometry

    Directory of Open Access Journals (Sweden)

    Kitatani Fumito

    2017-01-01

    Full Text Available Neutron Resonance Densitometry (NRD is a non-destructive assay technique of nuclear materials in particle-like debris that contains various materials. An aim of NRD is to quantify nuclear materials in a melting fuel of Fukusima Daiichi plant, spent nuclear fuel and annihilation disposal fuel etc. NRD consists of two techniques of Neutron Resonance Transmission Analysis (NRTA and Neutron Resonance Capture Analysis (NRCA or Prompt Gamma-ray Analysis (PGA. A density of nuclear material isotopes is decided with NRTA. The materials absorbing a neutron in a wide energy range such as boron in a sample are identified by NRCA/PGA. The information of NRCA/PGA is used in NRTA analysis to quantify nuclear material isotopes. A neutron time of flight (TOF method is used in NRD measurements. A facility, consisting of a neutron source, a neutron flight path, and a detector is required. A short flight path and a strong neutron source are needed to downsize such a facility and put NRD into practical use. A neutron transport tube covers a flight path to prevent noises. In order to investigate the effect of neutron transport tube and pulse width of a neutron source, we carried out NRTA experiments with a 2-m short neutron transport tube constructed at Kyoto University Research Reactor Institute - Linear Accelerator (KURRI-LINAC, and impacts of shield of neutron transport tube and influence of pulse width of a neutron source were examined. A shield of the neutron transport tube reduced a background and had a good influence on the measurement. The resonance dips of 183W at 27 eV was successfully observed with a pulse width of a neutron source less than 2 μs.

  19. Hybrid superconducting neutron detectors

    Energy Technology Data Exchange (ETDEWEB)

    Merlo, V.; Lucci, M.; Ottaviani, I. [Dipartimento di Fisica, Università Tor Vergata, Via della Ricerca Scientifica, I-00133 Roma (Italy); Salvato, M.; Cirillo, M. [Dipartimento di Fisica, Università Tor Vergata, Via della Ricerca Scientifica, I-00133 Roma (Italy); CNR SPIN Salerno, Università di Salerno, Via Giovanni Paolo II, n.132, 84084 Fisciano (Italy); Scherillo, A. [Science and Technology Facility Council, ISIS Facility Chilton, Didcot, Oxfordshire OX11 0QX (United Kingdom); Celentano, G. [ENEA Frascati Research Centre, Via. E. Fermi 45, 00044 Frascati (Italy); Pietropaolo, A., E-mail: antonino.pietropaolo@enea.it [ENEA Frascati Research Centre, Via. E. Fermi 45, 00044 Frascati (Italy); Mediterranean Institute of Fundamental Physics, Via Appia Nuova 31, 00040 Marino, Roma (Italy)

    2015-03-16

    A neutron detection concept is presented that is based on superconductive niobium (Nb) strips coated by a boron (B) layer. The working principle of the detector relies on the nuclear reaction, {sup 10}B + n → α + {sup 7}Li, with α and Li ions generating a hot spot on the current-biased Nb strip which in turn induces a superconducting-normal state transition. The latter is recognized as a voltage signal which is the evidence of the incident neutron. The above described detection principle has been experimentally assessed and verified by irradiating the samples with a pulsed neutron beam at the ISIS spallation neutron source (UK). It is found that the boron coated superconducting strips, kept at a temperature T = 8 K and current-biased below the critical current I{sub c}, are driven into the normal state upon thermal neutron irradiation. As a result of the transition, voltage pulses in excess of 40 mV are measured while the bias current can be properly modulated to bring the strip back to the superconducting state, thus resetting the detector. Measurements on the counting rate of the device are presented and the basic physical features of the detector are discussed.

  20. Hybrid Superconducting Neutron Detectors

    CERN Document Server

    Merlo, V; Cirillo, M; Lucci, M; Ottaviani, I; Scherillo, A; Celentano, G; Pietropaolo, A

    2014-01-01

    A new neutron detection concept is presented that is based on superconductive niobium (Nb) strips coated by a boron (B) layer. The working principle of the detector relies on the nuclear reaction 10B+n $\\rightarrow$ $\\alpha$+ 7Li , with $\\alpha$ and Li ions generating a hot spot on the current-biased Nb strip which in turn induces a superconducting-normal state transition. The latter is recognized as a voltage signal which is the evidence of the incident neutron. The above described detection principle has been experimentally assessed and verified by irradiating the samples with a pulsed neutron beam at the ISIS spallation neutron source (UK). It is found that the boron coated superconducting strips, kept at a temperature T = 8 K and current-biased below the critical current Ic, are driven into the normal state upon thermal neutron irradiation. As a result of the transition, voltage pulses in excess of 40 mV are measured while the bias current can be properly modulated to bring the strip back to the supercond...

  1. Neutron counting with cameras

    Energy Technology Data Exchange (ETDEWEB)

    Van Esch, Patrick; Crisanti, Marta; Mutti, Paolo [Institut Laue Langevin, Grenoble (France)

    2015-07-01

    A research project is presented in which we aim at counting individual neutrons with CCD-like cameras. We explore theoretically a technique that allows us to use imaging detectors as counting detectors at lower counting rates, and transits smoothly to continuous imaging at higher counting rates. As such, the hope is to combine the good background rejection properties of standard neutron counting detectors with the absence of dead time of integrating neutron imaging cameras as well as their very good spatial resolution. Compared to Xray detection, the essence of thermal neutron detection is the nuclear conversion reaction. The released energies involved are of the order of a few MeV, while X-ray detection releases energies of the order of the photon energy, which is in the 10 KeV range. Thanks to advances in camera technology which have resulted in increased quantum efficiency, lower noise, as well as increased frame rate up to 100 fps for CMOS-type cameras, this more than 100-fold higher available detection energy implies that the individual neutron detection light signal can be significantly above the noise level, as such allowing for discrimination and individual counting, which is hard to achieve with X-rays. The time scale of CMOS-type cameras doesn't allow one to consider time-of-flight measurements, but kinetic experiments in the 10 ms range are possible. The theory is next confronted to the first experimental results. (authors)

  2. Neutron whispering gallery

    Science.gov (United States)

    Nesvizhevsky, Valery V.; Voronin, Alexei Yu.; Cubitt, Robert; Protasov, Konstantin V.

    2010-02-01

    The `whispering gallery' effect has been known since ancient times for sound waves in air, later in water and more recently for a broad range of electromagnetic waves: radio, optics, Roentgen and so on. It consists of wave localization near a curved reflecting surface and is expected for waves of various natures, for instance, for atoms and neutrons. For matter waves, it would include a new feature: a massive particle would be settled in quantum states, with parameters depending on its mass. Here, we present for the first time the quantum whispering-gallery effect for cold neutrons. This phenomenon provides an example of an exactly solvable problem analogous to the `quantum bouncer'; it is complementary to the recently discovered gravitationally bound quantum states of neutrons . These two phenomena provide a direct demonstration of the weak equivalence principle for a massive particle in a pure quantum state. Deeply bound whispering-gallery states are long-living and weakly sensitive to surface potential; highly excited states are short-living and very sensitive to the wall potential shape. Therefore, they are a promising tool for studying fundamental neutron-matter interactions, quantum neutron optics and surface physics effects.

  3. Effect of Wood Aging on Wine Mineral Composition and (87)Sr/(86)Sr Isotopic Ratio.

    Science.gov (United States)

    Kaya, Ayse D; Bruno de Sousa, Raúl; Curvelo-Garcia, António S; Ricardo-da-Silva, Jorge M; Catarino, Sofia

    2017-06-14

    The evolution of mineral composition and wine strontium isotopic ratio (87)Sr/(86)Sr (Sr IR) during wood aging were investigated. A red wine was aged in stainless steel tanks with French oak staves (Quercus sessiliflora Salisb.), with three industrial scale replicates. Sampling was carried out after 30, 60, and 90 days of aging, and the wines were evaluated in terms of general analysis, phenolic composition, total polysaccharides, multielement composition, and Sr IR. Li, Be, Mg, Al, Sc, Ti, V, Mn, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Mo, Sb, Cs, Ba, Pr, Nd, Sm, Eu, Dy, Ho, Er, Yb, Lu, Tl, and Pb elements and (87)Sr/(86)Sr were determined by quadrupole inductively coupled plasma mass spectrometry (Q-ICP-MS) and Na, K, Ca, and Fe by flame atomic absorption spectrometry (FAAS). Two-way ANOVA was applied to assess wood aging and time effect on Sr IR and mineral composition. Wood aging resulted in significantly higher concentrations of Mg, V, Co, Ni, and Sr. At the end of the aging period, wine exhibited statistically identical Sr IR compared to control. Study suggests that wood aging does not affect (87)Sr/(86)Sr, not precluding the use of this parameter for wine traceability purposes.

  4. Diversity of Abundance Patterns of Light Neutron-capture Elements in Very-metal-poor Stars

    Science.gov (United States)

    Aoki, Misa; Ishimaru, Yuhri; Aoki, Wako; Wanajo, Shinya

    2017-03-01

    We determine the abundances of neutron-capture elements from Sr to Eu for five very-metal-poor stars (-3 universal pattern in the main r-process, similar to the abundance pattern of the r-process component of solar-system material. Still, it is uncertain whether the abundance pattern of the weak r-process shows universality or diversity, due to the sparseness of measured light neutron-capture elements. We have detected the key elements, Mo, Ru, and Pd, in five target stars to give an answer to this question. The abundance patterns of light neutron-capture elements from Sr to Pd suggest a diversity in the weak r-process. In particular, scatter in the abundance ratio between Ru and Pd is significant when the abundance patterns are normalized at Zr. Our results are compared with the elemental abundances predicted by nucleosynthesis models of supernovae with parameters such as electron fraction or proto-neutron-star mass, to investigate sources of such diversity in the abundance patterns of light neutron-capture elements. This paper presents that the variation in the abundances of observed stars can be explained with a small range of parameters, which can serve as constraints on future modeling of supernova models. Study based on data collected with the Subaru Telescope, operated by the National Astronomical Observatory of Japan.

  5. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... Events Spokespeople Email Alerts E-Newsletters About NHLBI Organization NHLBI Director Budget, Planning, & Legislative Advisory Committees Jobs ... severity of the condition. Treatments may include dietary changes, medicines, and surgery. Severe iron-deficiency anemia may ...

  6. Factor II deficiency

    Science.gov (United States)

    ... if one or more of these factors are missing or are not functioning like they should. Factor II is one such coagulation factor. Factor II deficiency runs in families (inherited) and is very rare. Both parents must ...

  7. Factor VII deficiency

    Science.gov (United States)

    ... if one or more of these factors are missing or are not functioning like they should. Factor VII is one such coagulation factor. Factor VII deficiency runs in families (inherited) and is very rare. Both parents must ...

  8. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... of Intramural Research Research Resources Research Meeting Summaries Technology Transfer Clinical Trials What Are Clinical Trials? Children & ... of the condition. Treatments may include dietary changes, medicines, and surgery. Severe iron-deficiency anemia may require ...

  9. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... iron-rich protein that carries oxygen from the lungs to the rest of the body. Iron-deficiency ... 2011 This video—presented by the National Heart, Lung, and Blood Institute, part of the National Institutes ...

  10. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... CAUSES WHO IS AT RISK SIGNS & SYMPTOMS DIAGNOSIS TREATMENTS PREVENTION LIVING WITH CLINICAL TRIALS LINKS Related Topics ... Doctors usually can successfully treat iron-deficiency anemia. Treatment will depend on the cause and severity of ...

  11. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... deficiency anemia may require treatment in a hospital, blood transfusions , iron injections, or intravenous iron therapy. Rate This ... video—presented by the National Heart, Lung, and Blood Institute, part of the National ...

  12. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... such as tiredness, poor skin tone, dizziness, and depression. After her doctor diagnosed her with iron-deficiency ... to stop her monthly periods. By following her treatment plan and making smart lifestyle choices, Susan continues ...

  13. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... Digg. Share this page from the NHLBI on Facebook. Add this link to the NHLBI to my ... Deficiency Anemia article. Updated: March 26, 2014 Twitter Facebook YouTube Google+ SITE INDEX ACCESSIBILITY PRIVACY STATEMENT FOIA ...

  14. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... chest pain, and other symptoms. Severe iron-deficiency anemia can lead to heart problems, infections, problems with growth and development in children, and other complications. Infants and young children and ...

  15. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... Events Spokespeople Email Alerts E-Newsletters About NHLBI Organization NHLBI Director Budget, Planning, & Legislative Advisory Committees Jobs ... food. Overview Iron-deficiency anemia is a common type of anemia . The term "anemia" usually refers to ...

  16. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... Events Spokespeople Email Alerts E-Newsletters About NHLBI Organization NHLBI Director Budget, Planning, & Legislative Advisory Committees Jobs ... the body. Iron-deficiency anemia usually develops over time if your body doesn't have enough iron ...

  17. Sleep Deprivation and Deficiency

    Science.gov (United States)

    ... page from the NHLBI on Twitter. What Are Sleep Deprivation and Deficiency? Sleep deprivation (DEP-rih-VA- ... Rate This Content: NEXT >> Updated: June 7, 2017 Sleep Infographic Sleep Disorders & Insufficient Sleep: Improving Health through ...

  18. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... chest pain, and other symptoms. Severe iron-deficiency anemia can lead to heart problems, infections, problems with growth and development in children, and other complications. Infants and young children and ...

  19. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... CAUSES WHO IS AT RISK SIGNS & SYMPTOMS DIAGNOSIS TREATMENTS PREVENTION LIVING WITH CLINICAL TRIALS LINKS Related Topics ... Doctors usually can successfully treat iron-deficiency anemia. Treatment will depend on the cause and severity of ...

  20. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... a waste product) from your body. Anemia also can occur if your red blood cells don't ... have less hemoglobin than normal. Iron-deficiency anemia can cause fatigue (tiredness), shortness of breath, chest pain, ...

  1. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... Intramural Research Research Resources Research Meeting Summaries Technology Transfer Clinical Trials What Are Clinical Trials? Children & Clinical ... iron-deficiency anemia may require treatment in a hospital, blood transfusions , iron injections, or intravenous iron therapy. ...

  2. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... symptoms. Severe iron-deficiency anemia can lead to heart problems, infections, problems with growth and development in ... 18/2011 This video—presented by the National Heart, Lung, and Blood Institute, part of the National ...

  3. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... of breath, chest pain, and other symptoms. Severe iron-deficiency anemia can lead to heart problems, infections, problems with growth and development in children, and other complications. Infants and young children and ...

  4. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... Digg. Share this page from the NHLBI on Facebook. Add this link to the NHLBI to my ... Deficiency Anemia article. Updated: March 26, 2014 Twitter Facebook YouTube Google+ SITE INDEX ACCESSIBILITY PRIVACY STATEMENT FOIA ...

  5. Virtual neutron scattering experiments

    DEFF Research Database (Denmark)

    Overgaard, Julie Hougaard; Bruun, Jesper; May, Michael

    2017-01-01

    We describe how virtual experiments can be utilized in a learning design that prepares students for hands-on experiments at large-scale facilities. We illustrate the design by showing how virtual experiments are used at the Niels Bohr Institute in a master level course on neutron scattering....... In the last week of the course, students travel to a large-scale neutron scattering facility to perform real neutron scattering experiments. Through student interviews and survey answers, we argue, that the virtual training prepares the students to engage more fruitfully with experiments by letting them focus...... on physics and data rather than the overwhelming instrumentation. We argue that this is because they can transfer their virtual experimental experience to the real-life situation. However, we also find that learning is still situated in the sense that only knowledge of particular experiments is transferred...

  6. Virtual neutron scattering experiments

    DEFF Research Database (Denmark)

    Overgaard, Julie Hougaard; Bruun, Jesper; May, Michael

    2016-01-01

    We describe how virtual experiments can be utilized in a learning design that prepares students for hands-on experiments at large-scale facilities. We illustrate the design by showing how virtual experiments are used at the Niels Bohr Institute in a master level course on neutron scattering....... In the last week of the course, students travel to a large-scale neutron scattering facility to perform real neutron scattering experiments. Through student interviews and survey answers, we argue, that the virtual training prepares the students to engage more fruitfully with experiments by letting them focus...... on physics and data rather than the overwhelming instrumentation. We argue that this is because they can transfer their virtual experimental experience to the real-life situation. However, we also find that learning is still situated in the sense that only knowledge of particular experiments is transferred...

  7. Direction sensitive neutron detector

    Energy Technology Data Exchange (ETDEWEB)

    Ahlen, Steven; Fisher, Peter; Dujmic, Denis; Wellenstein, Hermann F.; Inglis, Andrew

    2017-01-31

    A neutron detector includes a pressure vessel, an electrically conductive field cage assembly within the pressure vessel and an imaging subsystem. A pressurized gas mixture of CF.sub.4, .sup.3He and .sup.4He at respective partial pressures is used. The field cage establishes a relatively large drift region of low field strength, in which ionization electrons generated by neutron-He interactions are directed toward a substantially smaller amplification region of substantially higher field strength in which the ionization electrons undergo avalanche multiplication resulting in scintillation of the CF.sub.4 along scintillation tracks. The imaging system generates two-dimensional images of the scintillation patterns and employs track-finding to identify tracks and deduce the rate and direction of incident neutrons. One or more photo-multiplier tubes record the time-profile of the scintillation tracks permitting the determination of the third coordinate.

  8. Neutron absorbing alloy

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Masayuki

    1998-12-04

    The neutron absorbing alloy of the present invention comprises Ti or an alloy thereof as a mother material, to which from 2 to 40% by weight of Hf and Gd within a range of from 4 to 50% by weight in total are added respectively. Ti is excellent in specific strength, corrosion resistance and workability, and produces no noxious intermetallic compound with Hf and Gd. In addition, since the alloy can incorporate a great quantity of Hf and Gd, a neutron absorbing material having excellent neutron absorbing performance than usual and excellent in specific strength, corrosion resistance and workability can be manufactured conveniently and economically not by a special manufacturing method. (T.M.)

  9. Carbon neutron star atmospheres

    CERN Document Server

    Suleimanov, V F; Pavlov, G G; Werner, K

    2013-01-01

    The accuracy of measuring the basic parameters of neutron stars is limited in particular by uncertainties in chemical composition of their atmospheres. For example, atmospheres of thermally - emitting neutron stars in supernova remnants might have exotic chemical compositions, and for one of them, the neutron star in CasA, a pure carbon atmosphere has recently been suggested by Ho & Heinke (2009). To test such a composition for other similar sources, a publicly available detailed grid of carbon model atmosphere spectra is needed. We have computed such a grid using the standard LTE approximation and assuming that the magnetic field does not exceed 10^8 G. The opacities and pressure ionization effects are calculated using the Opacity Project approach. We describe the properties of our models and investigate the impact of the adopted assumptions and approximations on the emergent spectra.

  10. Uniformly rotating neutron stars

    CERN Document Server

    Boshkayev, Kuantay

    2016-01-01

    In this chapter we review the recent results on the equilibrium configurations of static and uniformly rotating neutron stars within the Hartle formalism. We start from the Einstein-Maxwell-Thomas-Fermi equations formulated and extended by Belvedere et al. (2012, 2014). We demonstrate how to conduct numerical integration of these equations for different central densities ${\\it \\rho}_c$ and angular velocities $\\Omega$ and compute the static $M^{stat}$ and rotating $M^{rot}$ masses, polar $R_p$ and equatorial $R_{\\rm eq}$ radii, eccentricity $\\epsilon$, moment of inertia $I$, angular momentum $J$, as well as the quadrupole moment $Q$ of the rotating configurations. In order to fulfill the stability criteria of rotating neutron stars we take into considerations the Keplerian mass-shedding limit and the axisymmetric secular instability. Furthermore, we construct the novel mass-radius relations, calculate the maximum mass and minimum rotation periods (maximum frequencies) of neutron stars. Eventually, we compare a...

  11. Corrosion resistant neutron absorbing coatings

    Science.gov (United States)

    Choi, Jor-Shan [El Cerrito, CA; Farmer, Joseph C [Tracy, CA; Lee, Chuck K [Hayward, CA; Walker, Jeffrey [Gaithersburg, MD; Russell, Paige [Las Vegas, NV; Kirkwood, Jon [Saint Leonard, MD; Yang, Nancy [Lafayette, CA; Champagne, Victor [Oxford, PA

    2012-05-29

    A method of forming a corrosion resistant neutron absorbing coating comprising the steps of spray or deposition or sputtering or welding processing to form a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material. Also a corrosion resistant neutron absorbing coating comprising a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material.

  12. Abundances of neutron-capture elements in G 24-25

    DEFF Research Database (Denmark)

    Liu, S.; Nissen, Poul Erik; Schuster, W. J.

    2012-01-01

    Aims. The differences between the neutron-capture element abundances of halo stars are important to our understanding of the nucleosynthesis of elements heavier than the iron group. We present a detailed abundance analysis of carbon and twelve neutron-capture elements from Sr up to Pb...... overabundances of carbon and heavy s-process elements and mild overabundances of Eu and light s-process elements. This abundance distribution is consistent with that of a typical CH giant. The abundance pattern can be explained by mass transfer from a former asymptotic giant branch component, which is now...

  13. Abundances of neutron-capture elements in G 24-25

    DEFF Research Database (Denmark)

    Liu, S.; Nissen, Poul Erik; Schuster, W. J.

    2012-01-01

    Aims. The differences between the neutron-capture element abundances of halo stars are important to our understanding of the nucleosynthesis of elements heavier than the iron group. We present a detailed abundance analysis of carbon and twelve neutron-capture elements from Sr up to Pb...... overabundances of carbon and heavy s-process elements and mild overabundances of Eu and light s-process elements. This abundance distribution is consistent with that of a typical CH giant. The abundance pattern can be explained by mass transfer from a former asymptotic giant branch component, which is now...

  14. Availability of essential trace elements in Ayurvedic Indian medicinal herbs using instrumental neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Singh, V.; Garg, A.N. [Nagpur Univ. (India). Dept. of Chemistry

    1997-01-01

    Specific parts of several plants (fruits, leaves, stem, bark and roots) often used as medicines in the Indian Ayurvedic system have been analysed for 20 elements (As, Ba, Br, Ca, Cl, Co, Cr, Cu, Fe, K, Mn, Mo, Na, P, Rb, Sb, Sc, Se, Sr and Zn) by employing instrumental neutron activation analysis (INAA). The samples were irradiated with thermal neutrons in a nuclear reactor and the induced activity was counted using high resolution gamma ray spectrometry. Most of the medicinal herbs have been found to be rich in one or more of the elements under study. (Author).

  15. Iron deficiency anemia

    OpenAIRE

    Naigamwalla, Dinaz Z.; Webb, Jinelle A.; Giger, Urs

    2012-01-01

    Iron is essential to virtually all living organisms and is integral to multiple metabolic functions. The most important function is oxygen transport in hemoglobin. Iron deficiency anemia in dogs and cats is usually caused by chronic blood loss and can be discovered incidentally as animals may have adapted to the anemia. Severe iron deficiency is characterized by a microcytic, hypochromic, potentially severe anemia with a variable regenerative response. Iron metabolism and homeostasis will be ...

  16. Proximal Focal Femoral Deficiency

    OpenAIRE

    Vishal Kalia, Vibhuti

    2008-01-01

    Proximal focal femoral deficiency (PFFD) is a developmental disorder of the proximal segment of thefemur and of acetabulum resulting in shortening of the affected limb and impairment of the function. It isa spectrum of congenital osseous anomalies characterized by a deficiency in the structure of the proximalfemur. The diagnosis is often made by radiological evaluation which includes identification and descriptionof PFFD and evaluation of associated limb anomalies by plain radiographs. Contra...

  17. Glucose-6-phosphatase deficiency.

    OpenAIRE

    Labrune Philippe; Gajdos Vincent; Eberschweiler Pascale; Hubert-Buron Aurélie; Petit François; Vianey-Saban Christine; Boudjemline Alix; Piraud Monique; Froissart Roseline

    2011-01-01

    Abstract Glucose-6-phosphatase deficiency (G6P deficiency), or glycogen storage disease type I (GSDI), is a group of inherited metabolic diseases, including types Ia and Ib, characterized by poor tolerance to fasting, growth retardation and hepatomegaly resulting from accumulation of glycogen and fat in the liver. Prevalence is unknown and annual incidence is around 1/100,000 births. GSDIa is the more frequent type, representing about 80% of GSDI patients. The disease commonly manifests, betw...

  18. Atmospheres around Neutron Stars

    Science.gov (United States)

    Fryer, Chris L.; Benz, Willy

    1994-12-01

    Interest in the behavior of atmospheres around neutron stars has grown astronomically in the past few years. Some of this interest arrived in the wake of the explosion of Supernova 1987A and its elusive remnant; spawning renewed interest in a method to insure material ``fall-back'' onto the adolescent neutron star in an effort to transform it into a silent black hole. However, the bulk of the activity with atmospheres around neutron stars is concentrated in stellar models with neutron star, rather than white dwarf, cores; otherwise known as Thorne-Zytkow objects. First a mere seed in the imagination of theorists, Thorne-Zytkow objects have grown into an observational reality with an ever-increasing list of formation scenarios and observational prospects. Unfortunately, the analytic work of Chevalier on supernova fall-back implies that, except for a few cases, the stellar simulations of Thorne-Zytkow objects are missing an important aspect of physics: neutrinos. Neutrino cooling removes the pressure support of these atmospheres, allowing accretion beyond the canonical Eddington rate for these objects. We present here the results of detailed hydrodynamical simulations in one and two dimensions with the additional physical effects of neutrinos, advanced equations of state, and relativity over a range of parameters for our atmosphere including entropy and chemical composition as well as a range in the neutron star size. In agreement with Chevalier, we find, under the current list of formation scenarios, that the creature envisioned by Thorne and Zytkow will not survive the enormous appetite of a neutron star. However, neutrino heating (a physical effect not considered in Chevalier's analysis) can play an important role in creating instabilities in some formation schemes, leading to an expulsion of matter rather than rapid accretion. By placing scrutiny upon the formation methods, we can determine the observational prospects for each.

  19. Pixelated neutron image plates

    Science.gov (United States)

    Schlapp, M.; Conrad, H.; von Seggern, H.

    2004-09-01

    Neutron image plates (NIPs) have found widespread application as neutron detectors for single-crystal and powder diffraction, small-angle scattering and tomography. After neutron exposure, the image plate can be read out by scanning with a laser. Commercially available NIPs consist of a powder mixture of BaFBr : Eu2+ and Gd2O3 dispersed in a polymer matrix and supported by a flexible polymer sheet. Since BaFBr : Eu2+ is an excellent x-ray storage phosphor, these NIPs are particularly sensitive to ggr-radiation, which is always present as a background radiation in neutron experiments. In this work we present results on NIPs consisting of KCl : Eu2+ and LiF that were fabricated into ceramic image plates in which the alkali halides act as a self-supporting matrix without the necessity for using a polymeric binder. An advantage of this type of NIP is the significantly reduced ggr-sensitivity. However, the much lower neutron absorption cross section of LiF compared with Gd2O3 demands a thicker image plate for obtaining comparable neutron absorption. The greater thickness of the NIP inevitably leads to a loss in spatial resolution of the image plate. However, this reduction in resolution can be restricted by a novel image plate concept in which a ceramic structure with square cells (referred to as a 'honeycomb') is embedded in the NIP, resulting in a pixelated image plate. In such a NIP the read-out light is confined to the particular illuminated pixel, decoupling the spatial resolution from the optical properties of the image plate material and morphology. In this work, a comparison of experimentally determined and simulated spatial resolutions of pixelated and unstructured image plates for a fixed read-out laser intensity is presented, as well as simulations of the properties of these NIPs at higher laser powers.

  20. POLARIZED NEUTRONS IN RHIC

    Energy Technology Data Exchange (ETDEWEB)

    COURANT,E.D.

    1998-04-27

    There does not appear to be any obvious way to accelerate neutrons, polarized or otherwise, to high energies by themselves. To investigate the behavior of polarized neutrons the authors therefore have to obtain them by accelerating them as components of heavier nuclei, and then sorting out the contribution of the neutrons in the analysis of the reactions produced by the heavy ion beams. The best neutron carriers for this purpose are probably {sup 3}He nuclei and deuterons. A polarized deuteron is primarily a combination of a proton and a neutron with their spins pointing in the same direction; in the {sup 3}He nucleus the spins of the two protons are opposite and the net spin (and magnetic moment) is almost the same as that of a free neutron. Polarized ions other than protons may be accelerated, stored and collided in a ring such as RHIC provided the techniques proposed for polarized proton operation can be adapted (or replaced by other strategies) for these ions. To accelerate polarized particles in a ring, one must make provisions for overcoming the depolarizing resonances that occur at certain energies. These resonances arise when the spin tune (ratio of spin precession frequency to orbit frequency) resonates with a component present in the horizontal field. The horizontal field oscillates with the vertical motion of the particles (due to vertical focusing); its frequency spectrum is dominated by the vertical oscillation frequency and its modulation by the periodic structure of the accelerator ring. In addition, the magnet imperfections that distort the closed orbit vertically contain all integral Fourier harmonics of the orbit frequency.

  1. Vitamin B12 deficiency.

    Science.gov (United States)

    Oh, Robert; Brown, David L

    2003-03-01

    Vitamin B12 (cobalamin) deficiency is a common cause of macrocytic anemia and has been implicated in a spectrum of neuropsychiatric disorders. The role of B12 deficiency in hyperhomocysteinemia and the promotion of atherosclerosis is only now being explored. Diagnosis of vitamin B12 deficiency is typically based on measurement of serum vitamin B12 levels; however, about 50 percent of patients with subclinical disease have normal B12 levels. A more sensitive method of screening for vitamin B12 deficiency is measurement of serum methylmalonic acid and homocysteine levels, which are increased early in vitamin B12 deficiency. Use of the Schilling test for detection of pernicious anemia has been supplanted for the most part by serologic testing for parietal cell and intrinsic factor antibodies. Contrary to prevailing medical practice, studies show that supplementation with oral vitamin B12 is a safe and effective treatment for the B12 deficiency state. Even when intrinsic factor is not present to aid in the absorption of vitamin B12 (pernicious anemia) or in other diseases that affect the usual absorption sites in the terminal ileum, oral therapy remains effective.

  2. New compact neutron polarizer

    Science.gov (United States)

    Krist, Th; Kennedy, S. J.; Hicks, T. J.; Mezei, F.

    A new type of a neutron polarizing bender was developed in co-operation with BENSC and ANSTO. It is based upon bent thin silicon wafers coated on one side with SiFeCo polarizing supermirrors and on the other side with Gd. Initial tests at BENSC in a 300 Oe magnetic field yielded a transmission of spin-up neutrons of about 55% over an angle range of 0.75° and flipping ratios > 30. Subsequent tests at ANSTO at 1200 Oe yielded a transmission of 48% with a flipping ratio > 45.

  3. FAST NEUTRONIC REACTOR

    Science.gov (United States)

    Snell, A.H.

    1957-12-01

    This patent relates to a reactor and process for carrying out a controlled fast neutron chain reaction. A cubical reactive mass, weighing at least 920 metric tons, of uranium metal containing predominantly U/sup 238/ and having a U/sup 235/ content of at least 7.63% is assembled and the maximum neutron reproduction ratio is limited to not substantially over 1.01 by insertion and removal of a varying amount of boron, the reactive mass being substantially freed of moderator.

  4. Helium 3 neutron precision polarimetry

    Science.gov (United States)

    Menard, Christopher

    2009-10-01

    Measuring neutron polarization to a high degree of precision is critical for the next generation of neutron decay correlation experiments. Polarized neutrons are also used in experiments to probe the hadronic weak interaction which contributes a small portion (˜10-7) of the force between nucleons. Using a beam of cold neutrons at Los Alamos Neutron Science Center (LANSCE), we polarized neutrons and measured their absolute polarization to ˜0.1%. Neutrons were polarized by passing them through a ^3He spin filter, relying on the maximally spin dependent 3He neutron absorption cross section. The neutron polarization can be determined by measuring the wavelength-dependent neutron transmission through the ^3He cell. An independent measurement of the neutron polarization was also obtained by passing the polarized beam through an RF spin flipper and a second polarized ^3He cell, used as an analyzer. To measure the efficiency of the spin flipper, the same measurements were made after reversing the ^3He polarization in the polarizer by using NMR techniques (adiabatic fast passage). We will show the consistency of these two measurements and the resulting precision of neutron polarimetry using these techniques.

  5. High-Resolution Spectroscopy of Sr and Y nuclei near N = Z line

    CERN Multimedia

    Dendooven, P

    2002-01-01

    The experiment IS377 aims for investigating the Gamow-Teller strength, isospin symmetry and proton-neutron interaction in the region a nuclide chart where large deformations occur. These studies need detailed information on the low-energy levels in the nuclei. Ground-state masses of Sr and Y nuclei will be studied by using the Penning-trap mass spectrometer ISOLTRAP and the low-energy levels of $^{75}$Rb and $^{78}$Y by $\\beta$-decay spectroscopy. The information obtained can be also used to extend the experimental database for astrophysical rapid proton capture modeling. During 2000 the first step was taken by measuring the masses of $^{76,77}$Sr. The improvement in the absolute mass value of $^{76}$Sr will lead to a significant gain in accuracy of the Gamow-Teller strength involved in the decay. The large deformation of this nucleus has been predicted to alter the strength distribution and this different pattern could be possibly used as a signature of a certain deformation. In addition, $^{76}$Sr, with its...

  6. Neutron storage time measurement for the neutron EDM experiment

    Science.gov (United States)

    Griffith, W. Clark; Ito, Takeyasu; Ramsey, John; Makela, Mark; Clayton, Steven; Hennings-Yeomans, Raul; Saidur Rahaman, M.; Currie, Scott; Womack, Todd; Sondheim, Walter; Cooper, Martin

    2010-11-01

    A new experiment to search for the neutron electric dipole moment (nEDM) is under development for installation at the Spallation Neutron Source (SNS) at Oakridge National Laboratory. The experiment will use ultra-cold neutrons (UCN) stored in superfluid helium, along with ^3He atoms acting as a neutron spin analyzer and comagnetometer. One crucial factor affecting the ultimate sensitivity of the experiment is the neutron storage time that can be obtained in the acrylic measurement cell. The acrylic cell walls will be coated with deuterated polystyrene (dPS), which is expected to give a wall loss factor of ˜room temperature and below 20 K.

  7. Neutron recognition in LAND detector for large neutron multiplicity

    CERN Document Server

    Pawłowski, P; Leifels, Y; Trautmann, W; Adrich, P; Aumann, T; Bacri, C O; Barczyk, T; Bassini, R; Bianchin, S; Boiano, C; Boretzky, K; Boudard, A; Chbihi, A; Cibor, J; Czech, B; De Napoli, M; Ducret, J -E; Emling, H; Frankland, J D; Gorbinet, T; Hellström, M; Henzlova, D; Hlavac, S; Immè, J; Iori, I; Johansson, H; Kezzar, K; Kupny, S; Lafriakh, A; Fèvre, A Le; Gentil, E Le; Leray, S; Łukasik, J; Lühning, J; Lynch, W G; Lynen, U; Majka, Z; Mocko, M; Müller, W F J; Mykulyak, A; Orth, H; Otte, A N; Palit, R; Panebianco, S; Pullia, A; Raciti, G; Rapisarda, E; Rossi, D; Salsac, M -D; Sann, H; Schwarz, C; Simon, H; Sfienti, C; Sümmerer, K; Tsang, M B; Verde, G; Veselsky, M; Volant, C; Wallace, M; Weick, H; Wiechula, J; Wieloch, A; Zwiegliński, B

    2012-01-01

    The performance of the LAND neutron detector is studied. Using an event-mixing technique based on one-neutron data obtained in the S107 experiment at the GSI laboratory, we test the efficiency of various analytic tools used to determine the multiplicity and kinematic properties of detected neutrons. A new algorithm developed recently for recognizing neutron showers from spectator decays in the ALADIN experiment S254 is described in detail. Its performance is assessed in comparison with other methods. The properties of the observed neutron events are used to estimate the detection efficiency of LAND in this experiment.

  8. Neutron beam imaging at neutron spectrometers at Dhruva

    Science.gov (United States)

    Desai, Shraddha S.; Rao, Mala N.

    2012-06-01

    A low efficiency, 2-Dimensional Position Sensitive Neutron Detector based on delay line position encoding is developed. It is designed to handle beam flux of 106-107 n/cm2/s and for monitoring intensity profiles of neutron beams. The present detector can be mounted in transmission mode, as the hardware allows maximum neutron transmission in sensitive region. Position resolution of 1.2 mm in X and Y directions, is obtained. Online monitoring of beam images and intensity profile of various neutron scattering spectrometers at Dhruva are presented. It shows better dynamic range of intensity over commercial neutron camera and is also time effective over the traditionally used photographic method.

  9. Structural chemistry and magnetic properties of the perovskite Sr3Fe2TeO9

    Science.gov (United States)

    Tang, Yawei; Hunter, Emily C.; Battle, Peter D.; Sena, Robert Paria; Hadermann, Joke; Avdeev, Maxim; Cadogan, J. M.

    2016-10-01

    A polycrystalline sample of perovskite-like Sr3Fe2TeO9 has been prepared in a solid-state reaction and studied by a combination of electron microscopy, Mössbauer spectroscopy, magnetometry, X-ray diffraction and neutron diffraction. The majority of the reaction product is shown to be a trigonal phase with a 2:1 ordered arrangement of Fe3+ and Te6+ cations. However, the sample is prone to nano-twinning and tetragonal domains with a different pattern of cation ordering exist within many crystallites. Antiferromagnetic ordering exists in the trigonal phase at 300 K and Sr3Fe2TeO9 is thus the first example of a perovskite with 2:1 trigonal cation ordering to show long-range magnetic order. At 300 K the antiferromagnetic phase coexists with two paramagnetic phases which show spin-glass behaviour below ~80 K.

  10. DFT LCAO and plane wave calculations of SrZrO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Evarestov, R.A.; Bandura, A.V.; Alexandrov, V.E. [Department of Quantum Chemistry, St. Petersburg State University, 26 Universitetskiy Prospekt, Stary Peterhof 198504 (Russian Federation); Kotomin, E.A. [Max-Planck-Institut fuer Festkoerperforschung, Heisenbergstr. 1, 70569, Stuttgart (Germany)

    2005-02-01

    The results of the density functional (DFT) LCAO and plane wave (PW) calculations of the electronic and structural properties of four known SrZrO{sub 3} phases (Pm3m, I4/mcm, Cmcm and Pbnm) are presented and discussed. The calculated unit cell energies and relative stability of these phases agree well with the experimental sequence of SrZrO{sub 3} phases as the temperature increases. The lattice structure parameters optimized in the PW calculations for all four phases are in good agreement with the experimental neutron diffraction data. The LCAO and PW results for the electronic structure, density of states and chemical bonding in the cubic phase (Pm3m) are discussed in detail and compared with the results of previous PW calculations. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  11. High-temperature phase transitions in SrHfO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, B.J.; Howard, C.J. [School of Chemistry, The University of Sydney, Sydney, New South Wales 2006 (Australia); Chakoumakos, B.C. [Solid State Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    1999-08-01

    The crystal structure of SrHfO{sub 3} has been studied at high temperatures using powder neutron diffraction and the Rietveld method. From 300 K to approximately 670 K the structure of SrHfO{sub 3} is orthorhombic ({ital Pnma}). By 870 K the material adopts a second orthorhombic structure ({ital Cmcm}). The material then undergoes a further phase transition and is tetragonal (I4/mcm) from {approximately}1000 to 1353 K. At higher temperatures ({gt}1360 K) the structure is the ideal cubic perovskite (Pm{bar 3}m). The angle of rotation of the oxygen octahedron in the tetragonal phase is taken as the order parameter and its temperature variation is consistent with a second order phase transition. {copyright} {ital 1999} {ital The American Physical Society}

  12. Sr7Co4(CO3)O(13-δ) (δ = 1.64), an original cobaltite derivative of the Ruddlesden-Popper series.

    Science.gov (United States)

    Demont, A; Pelloquin, D; Hébert, S; Hervieu, M; Höwing, J; Maignan, A

    2013-05-01

    The oxycarbonate Sr7Co4(CO3)O11.36 exhibits a peculiar structure that has been characterized by combining transmission electron microscopy analyses and neutron diffraction. It consists of a regular intergrowth between the m = 2 and carbonated m = 3 members of the Sr(m+1)Co(m)O3(m+1) Ruddlesden-Popper (RP) series, Sr3Co2O5.87 and Sr4Co2(CO3)O5.49, respectively. A description of the structure is proposed to provide identification of the different building blocks. This material is semiconducting and presents a complex magnetic behavior, characteristic of what is observed for the RP(2) or RP(3) series, with a cobalt valency close to 2.7.

  13. Magnetism of Bi{sub 0.75}Sr{sub 0.25}MnO{sub 3} and its dependence on bismuth concentration

    Energy Technology Data Exchange (ETDEWEB)

    Frontera, C. E-mail: frontera@icmab.es; Garcia-Munoz, J.L.; Carrillo, A.E.; Hervieu, M.; Martin, C.; Llobet, A.; Calleja, A.; Capdevila, X.G.; Ritter, C

    2004-05-01

    We present a magnetic and neutron powder diffraction study on Bi{sub 0.75}Sr{sub 0.25}MnO{sub 3}, Bi{sub 0.67}Sr{sub 0.33}MnO{sub 3} and Bi{sub 0.65}La{sub 0.1}Sr{sub 0.25}MnO{sub 3}. Bi{sub 0.75}Sr{sub 0.25}MnO{sub 3} presents, below T{sub CO}=600 K, a superstructure that doubles both a and c axes (P bnm setting). In contrast the other two compounds just double a cell parameter. At low temperature an antiferromagnetic structure appears, that is accompanied by a magnetoelastic effect on the cell parameters.

  14. Some Implications of Neutron Mirror Neutron Oscillation

    CERN Document Server

    Mohapatra, Rabindra N; Nussinov, S

    2005-01-01

    We comment on a recently discussed possibility of oscillations between neutrons and degenerate mirror neutrons in the context of mirror models for particles and forces. It has been noted by Bento and Berezhiani that if these oscillations occurred at a rate of $\\tau^{-1}_{NN'}\\sim sec^{-1}$, it would help explain putative super GKZ cosmic ray events provided the temperature of the mirror radiation is $\\sim 0.3-0.4$ times that of familiar cosmic microwave background radiation. We discuss how such oscillation time scales can be realized in mirror models and find that the simplest nonsupersymmetric model for this idea requires the existence of a low mass (30-3000 GeV) color triplet scalar or vector boson. A supersymmetric model, where this constraint can be avoided is severely constrained by the requirement of maintaining a cooler mirror sector. We also find that the reheat temperature after inflation in generic models that give fast $n-n'$ oscillation be less than about 100 GeV in order to maintain the required ...

  15. Neutron Scattering Investigations of Correlated Electron Systems and Neutron Instrumentation

    DEFF Research Database (Denmark)

    Holm, Sonja Lindahl

    are a unique probe for studying the atomic and molecular structure and dynamics of materials. Even though neutrons are very expensive to produce, the advantages neutrons provide overshadow the price. As neutrons interact weakly with materials compared to many other probes, e.g. electrons or photons......, it is possible to make a neutron scattering experiment through sample environment equipment like cryostats or pressure cells. Another advantage of neutron experiments is that the wavelength and energy of the neutron match the inter-atomic distances and basic excitations of solid materials. The scattering cross...... is not taken into account in previous reports on the field effect of magnetic scattering, since usually only L 0 is probed. A paper draft submitted for publication describing the results of elastic and inelastic neutron scattering experiments performed on the oxygen-doped La2CuO4+y HTSC is appended (Tc 40 K...

  16. Neutronic studies of the coupled moderators for spallation neutron sources

    Institute of Scientific and Technical Information of China (English)

    Yin Wen; Liang Jiu-Qing

    2005-01-01

    We investigate the neutronic performance of coupled moderators to be implemented in spallation neutron sources by Monte-Carlo simulation and give the slow neutron spectra for the cold and thermal moderators. CH4 moderator can provide slow neutrons with highly desirable characteristics and will be used in low-power spallation neutron soureces. The slow neutron intensity extracted from different angles has been calculated. The capability of moderation of liquid H2 is lower than H2O and liquid CH4 due to lower atomic number density of hydrogen but we can compensate for this disadvantage by using a premoderator. The H2O premoderator of 2cm thickness can reduce the heat deposition in the cold moderator by about 33% without spoiling the neutron pulse.

  17. Band gap tuning of epitaxial SrTiO{sub 3-δ}/Si(001) thin films through strain engineering

    Energy Technology Data Exchange (ETDEWEB)

    Cottier, Ryan J.; Steinle, Nathan A.; Currie, Daniel A.; Theodoropoulou, Nikoleta, E-mail: ntheo@txstate.edu [Physics Department, Texas State University, San Marcos, Texas 78666 (United States)

    2015-11-30

    We investigate the effect of strain and oxygen vacancies (V{sub O}) on the crystal and optical properties of oxygen deficient, ultra-thin (4–30 nm) films of SrTiO{sub 3-δ} (STO) grown heteroepitaxially on p-Si(001) substrates by molecular beam epitaxy. We demonstrate that STO band gap tuning can be achieved through strain engineering and show that the energy shift of the direct energy gap transition of SrTiO{sub 3-δ}/Si films has a quantifiable dimensional and doping dependence that correlates well with the changes in crystal structure.

  18. Neutron activation analysis and atomic absorption spectrophotometry for the analysis of fresh, pasteurised and powder milk

    Energy Technology Data Exchange (ETDEWEB)

    Wasim, M.; Rehman, S.; Arif, M.; Fatima, I.; Zaidi, J.H. [Pakistan Inst. of Nuclear Science and Technology, Islamabad (Pakistan). Chemistry Div.

    2012-07-01

    This study shows the application of semi-absolute k{sub 0} instrumental neutron activation analysis (k{sub 0}-INAA), epithermal neutron activation analysis (ENAA) and atomic absorption spectrophotometry (AAS) for the determination of 21 elements (Br, Ca, Cl, Co, Cr, Cs, Cu, Fe, Hf, I, K, Mg, Mn, Na, Ni, P, Pb, Rb, Sc Sr, and Zn) in different types of milk samples. The ENAA was required for the determination of iodine, AAS for Cu, Ni and Pb and the rest of the elements were measured by k{sub 0}-INAA. Thirteen elements (Br, Ca, Cl, Cs, Cu, Fe, K, Mg, Na, P, Rb, Sr and Zn) were identified in all milk samples. Ni was detected in eleven and Pb in two samples. Concentrations of most of the elements were within the ranges of the world reported data. The data was further explored by principal component analysis to find relationships between samples and elements. (orig.)

  19. Magnetic properties of CeSb and DySb from [mu][sup +]SR

    Energy Technology Data Exchange (ETDEWEB)

    Klauss, H.H. (Inst. fuer Metallphysik und Nukleare Festkoerperphysik, Technische Univ. Braunschweig (Germany)); Melo, M.A.C. de (Inst. fuer Metallphysik und Nukleare Festkoerperphysik, Technische Univ. Braunschweig (Germany)); Litterst, F.J. (Inst. fuer Metallphysik und Nukleare Festkoerperphysik, Technische Univ. Braunschweig (Germany)); Asch, L. (Physik Dept., Technische Univ. Muenchen, Garching (Germany)); Kratzer, A. (Physik Dept., Technische Univ. Muenchen, Garching (Germany)); Henneberger, S. (Physik Dept., Technische Univ. Muenchen, Garching (Germany)); Kalvius, G.M. (Physik Dept., Technische Univ. Muenchen, Garching (Germany)); Mattenberger, K. (Lab. fuer Festkoerperphysik, ETH Zuerich (Switzerland)); Hulliger, F. (Lab. fuer Festkoerperphysik, ETH Zuerich (Switzerland))

    1994-07-01

    ZF [mu]SR experiments on CeSb and DySb reveal fast spin dynamics even in their magnetically ordered states below 16.2 and 9.5 K, respectively. Above these first order transitions both pnictides exhibit strong frequency shifts in TF pointing to some magnetic precursors. The signals below T[sub N] show spontaneous rotating contributions. For CeSb several commensurately modulated antiferromagnetic phases containing paramagnetic sheets are confirmed. For DySb our data favor a CoO type structure in contrast to the MnO structure proposed from neutron diffraction. (orig.)

  20. A review on neutron reflectometry

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jeong Soo; Lee, Chang Hee; Shim, Hae Seop; Seong, Baek Seok

    1999-03-01

    This report contains principle and characteristic of neutron reflectometry. Therefore, in case of operating neutron reflectometer at HANARO in future, it will be a reference to the user who wishes to use the instrument effectively. Also, the current situation of neutron reflectometer operating in the world was examined. The detail of neutron reflectometer such as GANS(MURR), ADAM(ILL), POSY II(ANL), ROG(IRI) was described. The recent research situation on neutron reflectometry was also examined and it helps us to determine research field. (author)

  1. Neutron proton crystallography station (PCS)

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, Zoe [Los Alamos National Laboratory; Kovalevsky, Andrey [Los Alamos National Laboratory; Johnson, Hannah [Los Alamos National Laboratory; Mustyakimov, Marat [Los Alamos National Laboratory

    2009-01-01

    The PCS (Protein Crystallography Station) at Los Alamos Neutron Science Center (LANSCE) is a unique facility in the USA that is designed and optimized for detecting and collecting neutron diffraction data from macromolecular crystals. PCS utilizes the 20 Hz spallation neutron source at LANSCE to enable time-of-flight measurements using 0.6-7.0 {angstrom} neutrons. This increases the neutron flux on the sample by using a wavelength range that is optimal for studying macromolecular crystal structures. The diagram below show a schematic of PCS and photos of the detector and instrument cave.

  2. Neutron detection efficiency determinations for the TUNL neutron-neutron and neutron-proton scattering-length measurements

    Energy Technology Data Exchange (ETDEWEB)

    Trotter, D.E. Gonzalez [Department of Physics, Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States)], E-mail: crowell@tunl.duke.edu; Meneses, F. Salinas [Department of Physics, Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Tornow, W. [Department of Physics, Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States)], E-mail: tornow@tunl.duke.edu; Crowell, A.S.; Howell, C.R. [Department of Physics, Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Schmidt, D. [Physikalisch-Technische Bundesanstalt, D-38116, Braunschweig (Germany); Walter, R.L. [Department of Physics, Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States)

    2009-02-11

    The methods employed and the results obtained from measurements and calculations of the detection efficiency for the neutron detectors used at Triangle Universities Nuclear Laboratory (TUNL) in the simultaneous determination of the {sup 1}S{sub 0} neutron-neutron and neutron-proton scattering lengths a{sub nn} and a{sub np}, respectively, are described. Typical values for the detector efficiency were 0.3. Very good agreement between the different experimental methods and between data and calculation has been obtained in the neutron energy range below E{sub n}=13MeV.

  3. Cooling of Neutron Stars

    Directory of Open Access Journals (Sweden)

    Grigorian H.

    2010-10-01

    Full Text Available We introduce the theoretical basis for modeling the cooling evolution of compact stars starting from Boltzmann equations in curved space-time. We open a discussion on observational verification of different neutron star models by consistent statistics. Particular interest has the question of existence of quark matter deep inside of compact object, which has to have a specific influence on the cooling history of the star. Besides of consideration of several constraints and features of cooling evolution, which are susceptible of being critical for internal structure of hot compact stars we have introduced a method of extraction of the mass distribution of the neutron stars from temperature and age data. The resulting mass distribution has been compared with the one suggested by supernove simulations. This method can be considered as an additional checking tool for the consistency of theoretical modeling of neutron stars. We conclude that the cooling data allowed existence of neutron stars with quark cores even with one-flavor quark matter.

  4. New Neutron Dosimeter

    CERN Multimedia

    2001-01-01

    CERN has been operating an Individual Dosimetry Service for neutrons for about 35 years. The service was based on nuclear emulsions in the form of film packages which were developed and scanned in the Service. In 1999, the supplier of theses packages informed CERN that they will discontinue production of this material. TIS-RP decided to look for an external service provider for individual neutron dosimetry. After an extensive market survey and an invitation for tender, a supplier that met the stringent technical requirements set up by CERN's host states for personal dosimeters was identified. The new dosimeter is based on a track-etching technique. Neutrons have the capability of damaging plastic material. The microscopic damage centres are revealed by etching them in a strong acid. The resulting etch pits can be automatically counted and their density is proportional to dose equivalent from neutrons. On the technical side, the new dosimeter provides an improved independence of its response from energy and th...

  5. Neutron protein crystallography

    Energy Technology Data Exchange (ETDEWEB)

    Niimura, Nobuo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-10-01

    X-ray diffraction of single crystal has enriched the knowledge of various biological molecules such as proteins, DNA, t-RNA, viruses, etc. It is difficult to make structural analysis of hydrogen atoms in a protein using X-ray crystallography, whereas neutron diffraction seems usable to directly determine the location of those hydrogen atoms. Here, neutron diffraction method was applied to structural analysis of hen egg-white lysozyme. Since the crystal size of a protein to analyze is generally small (5 mm{sup 3} at most), the neutron beam at the sample position in monochromator system was set to less than 5 x 5 mm{sup 2} and beam divergence to 0.4 degree or less. Neutron imaging plate with {sup 6}Li or Gd mixed with photostimulated luminescence material was used and about 2500 Bragg reflections were recorded in one crystal setting. A total of 38278 reflections for 2.0 A resolution were collected in less than 10 days. Thus, stereo views of Trp-111 omit map around the indol ring of Trp-111 was presented and the three-dimensional arrangement of 696H and 264D atoms in the lysozyme molecules was determined using the omit map. (M.N.)

  6. Neutron capture reactions at DANCE

    Science.gov (United States)

    Bredeweg, T. A.

    2008-05-01

    The Detector for Advanced Neutron Capture Experiments (DANCE) is a 4π BaF2 array consisting of 160 active detector elements. The primary purpose of the array is to perform neutron capture cross section measurements on small (>~100 μg) and/or radioactive (DANCE we have performed neutron capture cross section measurements on a wide array of medium to heavy mass nuclides. Measurements to date include neutron capture cross sections on 241,243Am, neutron capture and neutron-induced fission cross sections and capture-to-fission ratio (α = σγ/σf) for 235U using a new fission-tagging detector as well as neutron capture cross sections for several astrophysics branch-point nuclei. Results from several of these measurements will be presented along with a discussion of additional physics information that can be extracted from the DANCE data.

  7. Nanostructure Neutron Converter Layer Development

    Science.gov (United States)

    Park, Cheol (Inventor); Sauti, Godfrey (Inventor); Kang, Jin Ho (Inventor); Lowther, Sharon E. (Inventor); Thibeault, Sheila A. (Inventor); Bryant, Robert G. (Inventor)

    2016-01-01

    Methods for making a neutron converter layer are provided. The various embodiment methods enable the formation of a single layer neutron converter material. The single layer neutron converter material formed according to the various embodiments may have a high neutron absorption cross section, tailored resistivity providing a good electric field penetration with submicron particles, and a high secondary electron emission coefficient. In an embodiment method a neutron converter layer may be formed by sequential supercritical fluid metallization of a porous nanostructure aerogel or polyimide film. In another embodiment method a neutron converter layer may be formed by simultaneous supercritical fluid metallization of a porous nanostructure aerogel or polyimide film. In a further embodiment method a neutron converter layer may be formed by in-situ metalized aerogel nanostructure development.

  8. Instrumental neutron activation analysis of soil and sediment samples from Siwa Oasis, Egypt

    Science.gov (United States)

    Badawy, Wael M.; Ali, Khaled; El-Samman, Hussein M.; Frontasyeva, Marina V.; Gundorina, Svetlana F.; Duliu, Octavian G.

    2015-07-01

    Instrumental neutron activation analysis was used to study geochemical peculiarities of the Siwa Oasis in the Western Egyptian Desert. A total of 34 elements were determined in soil and sediment samples (Na, Mg, Al, Cl, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, As, Br, Rb, Sr, Zr, Sb, I, Cs, Ba, La, Ce, Nd, Eu, Tb, Dy, Tm, Yb, Hf, Ta, Th, and U). For data interpretation Cluster analysis was applied. Comparison with the available literature data was carried out.

  9. Iron deficiency anaemia.

    Science.gov (United States)

    Lopez, Anthony; Cacoub, Patrice; Macdougall, Iain C; Peyrin-Biroulet, Laurent

    2016-02-27

    Anaemia affects roughly a third of the world's population; half the cases are due to iron deficiency. It is a major and global public health problem that affects maternal and child mortality, physical performance, and referral to health-care professionals. Children aged 0-5 years, women of childbearing age, and pregnant women are particularly at risk. Several chronic diseases are frequently associated with iron deficiency anaemia--notably chronic kidney disease, chronic heart failure, cancer, and inflammatory bowel disease. Measurement of serum ferritin, transferrin saturation, serum soluble transferrin receptors, and the serum soluble transferrin receptors-ferritin index are more accurate than classic red cell indices in the diagnosis of iron deficiency anaemia. In addition to the search for and treatment of the cause of iron deficiency, treatment strategies encompass prevention, including food fortification and iron supplementation. Oral iron is usually recommended as first-line therapy, but the most recent intravenous iron formulations, which have been available for nearly a decade, seem to replenish iron stores safely and effectively. Hepcidin has a key role in iron homoeostasis and could be a future diagnostic and therapeutic target. In this Seminar, we discuss the clinical presentation, epidemiology, pathophysiology, diagnosis, and acute management of iron deficiency anaemia, and outstanding research questions for treatment.

  10. Observation of Neutron Skyshine from an Accelerator Based Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    Franklyn, C. B. [Radiation Science Department, Necsa, PO Box 582, Pretoria 0001 (South Africa)

    2011-12-13

    A key feature of neutron based interrogation systems is the need for adequate provision of shielding around the facility. Accelerator facilities adapted for fast neutron generation are not necessarily suitably equipped to ensure complete containment of the vast quantity of neutrons generated, typically >10{sup 11} n{center_dot}s{sup -1}. Simulating the neutron leakage from a facility is not a simple exercise since the energy and directional distribution can only be approximated. Although adequate horizontal, planar shielding provision is made for a neutron generator facility, it is sometimes the case that vertical shielding is minimized, due to structural and economic constraints. It is further justified by assuming the atmosphere above a facility functions as an adequate radiation shield. It has become apparent that multiple neutron scattering within the atmosphere can result in a measurable dose of neutrons reaching ground level some distance from a facility, an effect commonly known as skyshine. This paper describes a neutron detection system developed to monitor neutrons detected several hundred metres from a neutron source due to the effect of skyshine.

  11. Neutron logging tool readings and neutron parameters of formations

    Science.gov (United States)

    Czubek, Jan A.

    1995-03-01

    A case history of the calibration of neutron porosity tools is given in the paper. The calibration of neutron porosity tools is one of the most difficult, complicated, and time consuming tasks in the well logging operations in geophysics. A semi empirical approach to this problem is given in the paper. It is based on the correlation of the tool readings observed in known environments with the apparent neutron parameters sensed by the tools. The apparent neutron parameters are functions of the true neutron parameters of geological formations and of the borehole material, borehole diameter, and the tool position inside the borehole. The true integral neutron transport parameters are obtained by the multigroup diffusion approximation for slowing down of neutrons and by one thermal neutron group for the diffusion. In the latter, the effective neutron temperature is taken into account. The problem of the thermal neutron absorption cross section of rocks is discussed in detail from the point of view of its importance for the well logging results and for the experimental techniques being used.

  12. Crystal structure, morphotropic phase transition and luminescence in the new cyclosilicates Sr3R2(Si3O9)2, R=Y, Eu-Lu

    Science.gov (United States)

    Tyutyunnik, Alexander P.; Leonidov, Ivan I.; Surat, Ludmila L.; Berger, Ivan F.; Zubkov, Vladimir G.

    2013-01-01

    A new series of promising luminescent materials, cyclosilicates Sr3R2(Si3O9)2, R=Y, Eu-Lu, has been synthesized via a solid-state reaction. X-ray and neutron powder diffraction studies show that these oxides crystallize in the monoclinic crystal system (S.G. C2/c, Z=4) and have a morphotropic phase transition between Er and Tm compounds followed by a step-like change of the unit cell constants. Isolated [Si3O9] rings located in layers are basic building units and stack with Sr/R layers along the [1 0 1¯] direction. The rare earth atoms are distributed among three independent Sr/R sites coordinated by 8, 7 and 6 oxygen atoms, and the Sr-R populations change from mixed to 0.5/0.5 over site (1) and full occupation of sites (2) and (3) by Sr and R, respectively, at the transition. Changes of the conformation and mutual arrangement of [Si3O9] rings, as well as exchange of oxygen atoms from the first and the second coordination sphere of two Sr/R sites also feature the phase transition. Luminescence in Sr3Y2(Si3O9)2:Eu3+ under ultraviolet (UV) excitation has been discussed.

  13. A Spatially Resolved Optical Second Harmonic Generation (SHG) Study of the Perovskite Iridate Sr2IrO4 with Bulk Sensitivity

    Science.gov (United States)

    Zhao, Liuyan; Chu, Hao; Torchinsky, Darius; Qi, Tongfei; Cao, Gang; Hsieh, David

    2014-03-01

    There has been a lot of recent interest in the layered perovskite iridate, Sr2IrO4, owing to its novel spin-orbital entangled Mott insulator ground state and its potential to realize high-Tc superconductivity upon doping. Although its bulk structural and magnetic point group symmetries have been characterized by resonant x-ray and neutron diffraction, these measurements provide spatially integrated information. In fact, recent neutron diffraction studies on Sr2IrO4 suggest that such measurements may be averaging over crystallographic domains of reduced symmetry that in turn generate distinct magnetic domains. Therefore, spatial resolution is desirable in order to gain full understanding of the point group symmetries of Sr2IrO4. Here, we show that optical SHG can provide a bulk sensitive measurement of the point group symmetries. By performing such SHG measurements in an imaging mode, we study the possible microscopic domain structures recently suggested. More generally, our SHG imaging technique provides an alternative way to probe the point group symmetries of iridate crystals, which are not always amenable to neutron scattering due to their small sample sizes and strong neutron absorption cross section. This work is supported by Army Research Office Grant Nos. W911NF-13-0059 and (ARO-DURIP) W911NF-13-1-0293.

  14. [Vitamin deficiencies and hypervitaminosis].

    Science.gov (United States)

    Mino, M

    1999-10-01

    There have recently been very few deficiencies with respect to fat soluble and water soluble vitamins in Japan All-trans-retinoic acid as induction or maintenance treatment improves disease free and overall survival against acute promyelocytic leukemia. In the isolated vitamin E deficiencies gene mutation has been cleared for alpha-tocopherol transferprotein. Recently, a relation of nutritional vitamin K intake and senile osteoporosis in women was epidemiologically demonstrated on a prospective study. Thiamin was yet noticed as development of deficiency in alcoholism, while the importance of supplemental folic acid during pregnancy has become especially clear in light of studies showing that folic acid supplements reduce the risk of neural tube defects in the fetus. With respect to hypervitaminosis, the Council for Responsible Nutrition (CRN), USA, has established safe intakes by identifying the NOAEL (No Observed Adverse Effect Level) and LOAEL (Lowest Observed Adverse Effect Level). Summaries of NOAEL and LOAEL for individual vitamins were shown.

  15. Antepartum Ornithine Transcarbamylase Deficiency

    Directory of Open Access Journals (Sweden)

    Hitoshi Nakajima

    2014-11-01

    Full Text Available Ornithine transcarbamylase deficiency (OTCD is the most common type urea cycle enzyme deficiencies. This syndrome results from a deficiency of the mitochondrial enzyme ornithine transcarbamylase, which catalyzes the conversion of ornithine and carbamoyl phosphate to citrullin. Our case was a 28-year-old female diagnosed with OTCD following neurocognitive deficit during her first pregnancy. Although hyperammonemia was suspected as the cause of the patient's mental changes, there was no evidence of chronic liver disease. Plasma amino acid and urine organic acid analysis revealed OTCD. After combined modality treatment with arginine, sodium benzoate and hemodialysis, the patient's plasma ammonia level stabilized and her mental status returned to normal. At last she recovered without any damage left.

  16. Neutron beam design for low intensity neutron and gamma-ray radioscopy using small neutron sources

    CERN Document Server

    Matsumoto, T

    2003-01-01

    Two small neutron sources of sup 2 sup 5 sup 2 Cf and sup 2 sup 4 sup 1 Am-Be radioisotopes were used for design of neutron beams applicable to low intensity neutron and gamma ray radioscopy (LINGR). In the design, Monte Carlo code (MCNP) was employed to generate neutron and gamma ray beams suited to LINGR. With a view to variable neutron spectrum and neutron intensity, various arrangements were first examined, and neutron-filter, gamma-ray shield and beam collimator were verified. Monte Carlo calculations indicated that with a suitable filter-shield-collimator arrangement, thermal neutron beam of 3,900 ncm sup - sup 2 s sup - sup 1 with neutron/gamma ratio of 7x10 sup 7 , and 25 ncm sup - sup 2 s sup - sup 1 with very large neutron/gamma ratio, respectively, could be produced by using sup 2 sup 5 sup 2 Cf(122 mu g) and a sup 2 sup 4 sup 1 Am-Be(37GBq)radioisotopes at the irradiation port of 35 cm from the neutron sources.

  17. Effect of new and conventional technological processes on the terroir marker 87Sr/86Sr

    Directory of Open Access Journals (Sweden)

    Catarino Sofia

    2016-01-01

    Full Text Available Aiming to use the strontium isotopic ratio 87Sr/86Sr for traceability and authentication of wine, it is crucial to understand the impacts of anthropogenic factor and technological processes on this parameter. In this study the effect of two technologies: nanofiltration (NF, applied for wine dealcoholisation (1, and ageing with oak wood staves (2, on 87Sr/86Sr ratio of wines from Portuguese Designations of Origin (DO, was assessed. Control wines, NF processed wines and wooden aged wines were evaluated for chemical composition, multi-elemental composition and 87Sr/86Sr ratio by Q-ICP-MS. Regarding NF experiments, high rejections to mineral elements, including heavy metals, were observed. Bearing in mind the several roles played by these elements in wine, this knowledge is of strategic importance in order to guarantee that NF process does not adversely affect product quality. Concerning wood ageing experiment, results indicate the influence of this technological process on metal physical-chemical stability. In the experimental conditions of this study, no significant effect of NF process and wood ageing on 87Sr/86Sr ratio was observed, suggesting that the application of these technologies in wine production is not a limitative factor for the use of 87Sr/86Sr ratio as a geographical origin marker.

  18. Maxdose-SR and popdose-SR routine release atmospheric dose models used at SRS

    Energy Technology Data Exchange (ETDEWEB)

    Jannik, G. T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Trimor, P. P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-07-28

    MAXDOSE-SR and POPDOSE-SR are used to calculate dose to the offsite Reference Person and to the surrounding Savannah River Site (SRS) population respectively following routine releases of atmospheric radioactivity. These models are currently accessed through the Dose Model Version 2014 graphical user interface (GUI). MAXDOSE-SR and POPDOSE-SR are personal computer (PC) versions of MAXIGASP and POPGASP, which both resided on the SRS IBM Mainframe. These two codes follow U.S. Nuclear Regulatory Commission (USNRC) Regulatory Guides 1.109 and 1.111 (1977a, 1977b). The basis for MAXDOSE-SR and POPDOSE-SR are USNRC developed codes XOQDOQ (Sagendorf et. al 1982) and GASPAR (Eckerman et. al 1980). Both of these codes have previously been verified for use at SRS (Simpkins 1999 and 2000). The revisions incorporated into MAXDOSE-SR and POPDOSE-SR Version 2014 (hereafter referred to as MAXDOSE-SR and POPDOSE-SR unless otherwise noted) were made per Computer Program Modification Tracker (CPMT) number Q-CMT-A-00016 (Appendix D). Version 2014 was verified for use at SRS in Dixon (2014).

  19. Raman scattering, magnetization and magnetotransport study of SrFeO{sub 3-{delta}}, Sr{sub 3}Fe{sub 2}O{sub 7-{delta}} and CaFeO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Damljanovic, Vladimir

    2008-12-16

    In this thesis we have determined the Raman spectra as well as the magnetization, resistance and magnetoresistance of the compounds SrFeO{sub 3-{delta}}, Sr{sub 3}Fe{sub 2}O{sub 7-{delta}} and CaFeO{sub 3} as a function of temperature. We describe the preparation of nearly stoichiometric SrFeO{sub 3-{delta}} crystals with {delta}<0.05. we have performed lattice dynamics calculations for the ideal composition SrFeO{sub 3.00} in order to assign the phonon modes observed in infra-red experiments. We have measured the Raman spectra of the tetragonal phase in the temperature range 13 K to 300 K and of the orthorhombic phase in the temperature range 6 K to 475 K. We have measured the temperature dependence of the magnetization for the magnetic field along high-symmetry axes of the crystal structure. We have also performed neutron diffraction measurements. The resistivity and the magnetoresistance were measured in the range 10 K to 300 K. Finally we have measured the Raman spectra of the same sample in the temperature range 15 K to 440 K. In order to assign the observed modes, we have performed lattice dynamics calculations based on the published crystal structure of Sr{sub 3}Fe{sub 2}O{sub 7}. (orig.)

  20. Mortality and GH deficiency

    DEFF Research Database (Denmark)

    Stochholm, Kirstine; Gravholt, Claus Højbjerg; Laursen, Torben;

    2007-01-01

    OBJECTIVE: To estimate the mortality in Denmark in patients suffering from GH deficiency (GHD). DESIGN: Mortality was analyzed in 1794 GHD patients and 8014 controls matched on age and gender. All records in GHD patients were studied and additional morbidity noted. Patients were divided into chil......OBJECTIVE: To estimate the mortality in Denmark in patients suffering from GH deficiency (GHD). DESIGN: Mortality was analyzed in 1794 GHD patients and 8014 controls matched on age and gender. All records in GHD patients were studied and additional morbidity noted. Patients were divided...

  1. La2SrCr2O7: Controlling the Tilting Distortions of n = 2 Ruddlesden-Popper Phases through A-Site Cation Order.

    Science.gov (United States)

    Zhang, Ronghuan; Abbett, Brian M; Read, Gareth; Lang, Franz; Lancaster, Tom; Tran, T Thao; Halasyamani, P Shiv; Blundell, Stephen J; Benedek, Nicole A; Hayward, Michael A

    2016-09-06

    Structural characterization by neutron diffraction, supported by magnetic, SHG, and μ(+)SR data, reveals that the n = 2 Ruddlesden-Popper phase La2SrCr2O7 adopts a highly unusual structural configuration in which the cooperative rotations of the CrO6 octahedra are out of phase in all three Cartesian directions (ΦΦΦz/ΦΦΦz; a(-)a(-)c(-)/a(-)a(-)c(-)) as described in space group A2/a. First-principles DFT calculations indicate that this unusual structural arrangement can be attributed to coupling between the La/Sr A-site distribution and the rotations of the CrO6 units, which combine to relieve the local deformations of the chromium-oxygen octahedra. This coupling suggests new chemical "handles" by which the rotational distortions or A-site cation order of Ruddlesden-Popper phases can be directed to optimize physical behavior. Low-temperature neutron diffraction data and μ(+)SR data indicate La2SrCr2O7 adopts a G-type antiferromagnetically ordered state below TN ∼ 260 K.

  2. Neutron Scattering Investigations of Correlated Electron Systems and Neutron Instrumentation

    DEFF Research Database (Denmark)

    Holm, Sonja Lindahl

    are a unique probe for studying the atomic and molecular structure and dynamics of materials. Even though neutrons are very expensive to produce, the advantages neutrons provide overshadow the price. As neutrons interact weakly with materials compared to many other probes, e.g. electrons or photons......, it is possible to make a neutron scattering experiment through sample environment equipment like cryostats or pressure cells. Another advantage of neutron experiments is that the wavelength and energy of the neutron match the inter-atomic distances and basic excitations of solid materials. The scattering cross...... magnetism. This is in contrast to what is observed as the critical temperature is slightly lower for this system compared to other co-doped systems, suggesting that the magnetic and superconducting phases co-exist. A published manuscript describes the study of magnetic and superconducting properties of Ba...

  3. Neutron-gamma competition for $\\beta$-delayed neutron emission

    CERN Document Server

    Mumpower, Matthew; Moller, Peter

    2016-01-01

    We present a coupled Quasi-particle Random Phase Approximation and Hauser-Feshbach (QRPA+HF) model for calculating delayed particle emission. This approach uses microscopic nuclear structure information which starts with Gamow-Teller strength distributions in the daughter nucleus, and then follows the statistical decay until the initial available excitation energy is exhausted. Explicitly included at each particle emission stage is $\\gamma$-ray competition. We explore this model in the context of neutron emission of neutron-rich nuclei and find that neutron-gamma competition can lead to both increases and decreases in neutron emission probabilities, depending on the system considered. A second consequence of this formalism is a prediction of more neutrons on average being emitted after $\\beta$-decay for nuclei near the neutron dripline compared to models that do not consider the statistical decay.

  4. Examination of SR101 shipping packages

    Energy Technology Data Exchange (ETDEWEB)

    Daugherty, W. L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-03-01

    Four SR101 shipping packages were removed from service and provided for disassembly and examination of the internal fiberboard assemblies. These packages were 20 years old, and had experienced varying levels of degradation. Two of the packages were successfully disassembled and fiberboard samples were removed from these packages and tested. Mechanical and thermal property values are generally comparable to or higher than baseline values measured on fiberboard from 9975 packages, which differs primarily in the specified density range. While baseline data for the SR101 material is not available, this comparison with 9975 material suggests that the material properties of the SR101 fiberboard have not significantly degraded.

  5. Laser Spectroscopy of Neutron Rich Bismuth Isotopes

    CERN Multimedia

    2002-01-01

    %IS344 :\\\\ \\\\ The aim of the experiment is to measure the optical isotope shifts and hyperfine structures of bismuth isotopes across the N=126 shell closure in order to extract the change in mean square charge radii ($\\delta\\langle r^{2}\\rangle$) and static moments. These include the first isotones of lead to be measured directly above the shell closure and will provide new information on the systematics of the kink ($\\delta\\langle r^{2}\\rangle)$ seen in the lead isotopic chain. After two very successful runs the programme has been extended to include the neutron deficient isotopes below $^{201}$Bi to study the systematics across the $i_{13/2}$ neutron sub-shell closure at N=118.\\\\ \\\\ During the initial 2 runs (9 shifts) the isotope shifts and hyperfine structures of three new isotopes, $ ^{210,212,213}$Bi and the 9$^{-}$ isomer of $^{210}$Bi have been measured. The accuracy of the previous measurements of $^{205,206,208}$Bi have been greatly improved. The samples of $ ^{208,210,210^{m}}$Bi were prepared by c...

  6. Fast neutron imaging device and method

    Science.gov (United States)

    Popov, Vladimir; Degtiarenko, Pavel; Musatov, Igor V.

    2014-02-11

    A fast neutron imaging apparatus and method of constructing fast neutron radiography images, the apparatus including a neutron source and a detector that provides event-by-event acquisition of position and energy deposition, and optionally timing and pulse shape for each individual neutron event detected by the detector. The method for constructing fast neutron radiography images utilizes the apparatus of the invention.

  7. Progress of Neutron Bubble Detectors in CIAE

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Neutron bubble detector is the only personal neutron dosimeter which has adequate neutronsensitivity to meet the implications of the ICRP 60 recommendations for neutron dosimetry. It canmonitor the wide range of neutron energy, for example 100 eV to 10 MeV And it becomes a significanttool for neutron dose monitoring at the environment of nuclear energy.

  8. Measurement of neutron scattering lengths using neutron interferometry

    Science.gov (United States)

    Shahi, Chandra B.

    This thesis describes the details on building a new Neutron Interferometry and Optics Facility (NIOFa), the measurement of the incoherent neutron scattering length bi of 3He, and the measurement of the coherent neutron scattering length bc of 4He at National Institute of Standards and Technology (NIST) Center for Neutron Research (NCNR). A new monochromatic beamline and facility has been installed at the NCNR devoted to neutron interferometry in the research areas of spin control, spin manipulation, quantum mechanics, quantum information science, spintronics, and material science. This facility is possible in part because of advances in decoherence free subspace interferometer designs that have demonstrated consistent contrast in the presence of vibrational noise; a major environmental constraint that has prevented neutron interferometry from being applied at other neutron facilities. This new facility, NIOFa, is located in the guide hall of the NCNR upstream of the existing Neutron Interferometry and Optics Facility (NIOF) and has several advantages over the NIOF including higher incident flux, better neutron polarization, and increased accessibility. The measurement of the incoherent neutron scattering length bi of 3He was done using a (220) single silicon crystal skew symmetric interferometer. This experiment requires both a polarized beam and a polarized target. We report bi = -2.35 +/- 0.014 (stat.) +/- 0.014 (syst.). This experiment is a revision of the previous experiment which was done in 2008, and partially explains the non-zero phase shift seen in 2008 experiment even if target cell was completely unpolarized. The measurement of the coherent neutron scattering length b c of the 4He was done using a (111) single silicon crystal interferometer. The neutron interferometry and optics facility at NIST had been used previously to determine the coherent scattering lengths for n- 1H, n-2H, and n-3He to less than 1% relative uncertainty. We report bc of the 4He

  9. Structural phases driven by oxygen vacancies at the La{sub 0.7}Sr{sub 0.3}MnO{sub 3}/SrTiO{sub 3} hetero-interface

    Energy Technology Data Exchange (ETDEWEB)

    Nord, M.; Holmestad, R. [Department of Physics, NTNU, 7491 Trondheim (Norway); Vullum, P. E. [Department of Physics, NTNU, 7491 Trondheim (Norway); Materials and Chemistry, SINTEF, 7465 Trondheim (Norway); Moreau, M.; Boschker, J. E.; Tybell, T., E-mail: thomas.tybell@iet.ntnu.no [Department of Electronics and Telecommunications, NTNU, 7491 Trondheim (Norway); Selbach, S. M. [Department of Materials Science and Engineering, NTNU, 7491 Trondheim (Norway)

    2015-01-26

    An oxygen vacancy driven structural response at the epitaxial interface between La{sub 0.7}Sr{sub 0.3}MnO{sub 3} films and SrTiO{sub 3} substrates is reported. A combined scanning transmission electron microscopy and electron energy loss spectroscopy study reveal the presence of an elongated out-of-plane lattice parameter, coupled to oxygen vacancies and reduced manganese oxidation state at the La{sub 0.7}Sr{sub 0.3}MnO{sub 3} side of the interface. Density functional theory calculations support that the measured interface structure is a disordered oxygen deficient brownmillerite structure. The effect of oxygen vacancy mobility is assessed, revealing an ordering of the vacancies with time.

  10. Neutron electric polarizability

    CERN Document Server

    Alexandru, Andrei

    2009-01-01

    We use the background field method to extract the "connected" piece of the neutron electric polarizability. We present results for quenched simulations using both clover and Wilson fermions and discuss our experience in extracting the mass shifts and the challenges we encountered when we lowered the quark mass. For the neutron we find that as the pion mass is lowered below $500\\MeV$, the polarizability starts rising in agreement with predictions from chiral perturbation theory. For our lowest pion mass, $m_\\pi=320\\MeV$, we find that $\\alpha_n = 3.8(1.3)\\times 10^{-4}\\fm^3$, which is still only one third of the experimental value. We also present results for the neutral pion; we find that its polarizability turns negative for pion masses smaller than $500\\MeV$ which is puzzling.

  11. Neutron beam measurement dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Amaro, C.R. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

    1995-11-01

    This report describes animal dosimetry studies and phantom measurements. During 1994, 12 dogs were irradiated at BMRR as part of a 4 fraction dose tolerance study. The animals were first infused with BSH and irradiated daily for 4 consecutive days. BNL irradiated 2 beagles as part of their dose tolerance study using BPA fructose. In addition, a dog at WSU was irradiated at BMRR after an infusion of BPA fructose. During 1994, the INEL BNCT dosimetry team measured neutron flux and gamma dose profiles in two phantoms exposed to the epithermal neutron beam at the BMRR. These measurements were performed as a preparatory step to the commencement of human clinical trials in progress at the BMRR.

  12. Neutron Scattering Stiudies

    Energy Technology Data Exchange (ETDEWEB)

    Kegel, Gunter H.R.; Egan, James J

    2007-04-18

    This project covers four principal areas of research: Elastic and inelastic neutron scattering studies in odd-A terbium, thulium and other highly deformed nuclei near A=160 with special regard to interband transitions and to the investigation of the direct-interaction versus the compound-nucleus excitation process in these nuclei. Examination of new, fast photomultiplier tubes suitable for use in a miniaturized neutron-time-of-flight spectrometer. Measurement of certain inelastic cross sections of 238U. Determination of the multiplicity of prompt fission gamma rays in even-A fissile actinides. Energies and mean lives of fission isomers produced by fast fission of even-Z, even-A actinides. Study of the mean life of 7Be in different host matrices and its possible astro-physical significance.

  13. Neutrons from Antiproton Irradiation

    DEFF Research Database (Denmark)

    Bassler, Niels; Holzscheiter, Michael; Petersen, Jørgen B.B.

    Background: Radiotherapy with Antiprotons is currently investigated by the AD-4/ACE collaboration. The hypothesis is that the additional energy released from the antiprotons annihilating at the target nuclei can enable a reduced dose in the entry channel of the primary beam. Furthermore an enhanced...... relative biological effect (RBE) has already been beam measured in spread out Bragg peaks of antiprotons, relative to that found in the plateau region. However, the antiproton annihilation process is associated with a substantial release of secondary particles which contribute to the dose outside...... the neutron spectrum. Additionally, we used a cylindrical polystyrene loaded with several pairs of thermoluminescent detectors containing Lithium-6 and Lithium-7, which effectively detects thermalized neutrons. The obtained results are compared with FLUKA imulations. Results: The results obtained...

  14. Sr fluxes and isotopic compositions of the eleven rivers originating from the Qinghai-Tibet Plateau and their contributions to 87Sr/86Sr evolution of seawater

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    To evaluate influence of chemical weathering of the Qinghai-Tibet Plateau (QTP) on seawater 87Sr/86Sr variation, river water and sediment samples were collected, and their Sr concentrations and isotopic compositions analyzed, from the seven large rivers that originated from the QTP. By combining these with the data of the Ganges, Brahmaputra, Indus and Irrawaddy originated in the southern QTP, the total Sr flux of the eleven rivers reaches 3.47×109 mol·a-1, which accounts for 10.2% of the total Sr flux transported by the global rivers. The weighted mean 87Sr/86Sr is 0.71694, higher than the average value of the global rivers. The 87Srex (87Sr flux in excess of the seawater 87Sr/86Sr ratio) of the Chinese seven rivers is 1.55×106 mol·a-1, only accounting for about 6% of the value of the eleven rivers originated from QTP, and the Ganges-Brahmaputra system accounts for 86%. We assume that the QTP rivers have no strontium contributions to the oceans before ~40 Ma and the Sr fluxes of the global rivers, except the QTP eleven rivers, are constant, then a maximum linear increase in Sr fluxes of the QTP rivers from zero to the modern value in response to tectonic uplift can explain ~69% increase of seawater 87Sr/86Sr over the past ~40 Ma and the remainder of 31% is perhaps provided from other factors.

  15. Iodine-deficiency disorders

    NARCIS (Netherlands)

    Zimmermann, M.B.; Jooste, P.L.; Pandav, C.S.

    2008-01-01

    billion individuals worldwide have insufficient iodine intake, with those in south Asia and sub-Saharan Africa particularly affected. Iodine deficiency has many adverse effects on growth and development. These effects are due to inadequate production of thyroid hormone and are termed iodine-deficien

  16. Factor V deficiency

    Science.gov (United States)

    ... When certain blood clotting factors are low or missing, your blood does not clot properly. Factor V deficiency is rare. It may be caused by: A defective Factor V gene passed down through families (inherited) An antibody that interferes with normal Factor ...

  17. Alpha1-antitrypsin deficiency

    DEFF Research Database (Denmark)

    Stolk, Jan; Seersholm, Niels; Kalsheker, Noor

    2006-01-01

    biennially to exchange views and research findings. The fourth biennial meeting was held in Copenhagen, Denmark, on 2-3 June 2005. This review covers the wide range of AAT deficiency-related topics that were addressed encompassing advances in genetic characterization, risk factor identification, clinical...... epidemiology, inflammatory and signalling processes, therapeutic advances, and lung imaging techniques....

  18. MCAD deficiency in Denmark

    DEFF Research Database (Denmark)

    Andresen, Brage Storstein; Lund, Allan Meldgaard; Hougaard, David Michael

    2012-01-01

    Medium-chain acyl-CoA dehydrogenase deficiency (MCADD) is the most common defect of fatty acid oxidation. Many countries have introduced newborn screening for MCADD, because characteristic acylcarnitines can easily be identified in filter paper blood spot samples by tandem mass spectrometry (MS...

  19. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... blood transfusions , iron injections, or intravenous iron therapy. Rate This Content: NEXT >> Featured Video Living With and Managing Iron-Deficiency Anemia 05/18/2011 This video—presented by the National Heart, Lung, and Blood Institute, part of the National ...

  20. Iodine-deficiency disorders

    NARCIS (Netherlands)

    Zimmermann, M.B.; Jooste, P.L.; Pandav, C.S.

    2008-01-01

    billion individuals worldwide have insufficient iodine intake, with those in south Asia and sub-Saharan Africa particularly affected. Iodine deficiency has many adverse effects on growth and development. These effects are due to inadequate production of thyroid hormone and are termed iodine-deficien

  1. Vitamin B12 deficiency

    Science.gov (United States)

    Vitamin B12 (B12; also known as cobalamin) is a B vitamin that has an important role in cellular metabolism, especially in DNA synthesis, methylation and mitochondrial metabolism. Clinical B12 deficiency with classic haematological and neurological manifestations is relatively uncommon. However, sub...

  2. Morbidity and GH deficiency

    DEFF Research Database (Denmark)

    Stochholm, Kirstine; Laursen, Torben; Green, Anders;

    2008-01-01

    OBJECTIVE: To estimate morbidity in Denmark in all patients with GH deficiency (GHD). DESIGN: Morbidity was analyzed in 1794 GHD patients and 8014 controls matched on age and gender. All records in the GHD patients were studied and additional morbidity noted. Diagnoses and dates of admissions were...

  3. Diagnosing oceanic nutrient deficiency

    Science.gov (United States)

    Moore, C. Mark

    2016-11-01

    The supply of a range of nutrient elements to surface waters is an important driver of oceanic production and the subsequent linked cycling of the nutrients and carbon. Relative deficiencies of different nutrients with respect to biological requirements, within both surface and internal water masses, can be both a key indicator and driver of the potential for these nutrients to become limiting for the production of new organic material in the upper ocean. The availability of high-quality, full-depth and global-scale datasets on the concentrations of a wide range of both macro- and micro-nutrients produced through the international GEOTRACES programme provides the potential for estimation of multi-element deficiencies at unprecedented scales. Resultant coherent large-scale patterns in diagnosed deficiency can be linked to the interacting physical-chemical-biological processes which drive upper ocean nutrient biogeochemistry. Calculations of ranked deficiencies across multiple elements further highlight important remaining uncertainties in the stoichiometric plasticity of nutrient ratios within oceanic microbial systems and caveats with regards to linkages to upper ocean nutrient limitation. This article is part of the themed issue 'Biological and climatic impacts of ocean trace element chemistry'.

  4. Manganese deficiency in plants

    DEFF Research Database (Denmark)

    Schmidt, Sidsel Birkelund; Jensen, Poul Erik; Husted, Søren

    2016-01-01

    Manganese (Mn) is an essential plant micronutrient with an indispensable function as a catalyst in the oxygen-evolving complex (OEC) of photosystem II (PSII). Even so, Mn deficiency frequently occurs without visual leaf symptoms, thereby masking the distribution and dimension of the problem...

  5. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... blood transfusions , iron injections, or intravenous iron therapy. Rate This Content: NEXT >> Featured Video Living With and Managing Iron-Deficiency Anemia 05/18/2011 This video—presented by the National Heart, Lung, and Blood Institute, part of the National ...

  6. Neutron Transport Simulations for NIST Neutron Lifetime Experiment

    Science.gov (United States)

    Li, Fangchen; BL2 Collaboration Collaboration

    2016-09-01

    Neutrons in stable nuclei can exist forever; a free neutron lasts for about 15 minutes on average before it beta decays to a proton, an electron, and an antineutrino. Precision measurements of the neutron lifetime test the validity of weak interaction theory and provide input into the theory of the evolution of light elements in the early universe. There are two predominant ways of measuring the neutron lifetime: the bottle method and the beam method. The bottle method measures decays of ultracold neutrons that are stored in a bottle. The beam method measures decay protons in a beam of cold neutrons of known flux. An improved beam experiment is being prepared at the National Institute of Science and Technology (Gaithersburg, MD) with the goal of reducing statistical and systematic uncertainties to the level of 1 s. The purpose of my studies was to develop computer simulations of neutron transport to determine the beam collimation and study the neutron distribution's effect on systematic effects for the experiment, such as the solid angle of the neutron flux monitor. The motivation for the experiment and the results of this work will be presented. This work was supported, in part, by a Grant to Gettysburg College from the Howard Hughes Medical Institute through the Precollege and Undergraduate Science Education Program.

  7. High-resolution neutron microtomography with noiseless neutron counting detector

    Energy Technology Data Exchange (ETDEWEB)

    Tremsin, A.S., E-mail: ast@ssl.berkeley.edu [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); McPhate, J.B.; Vallerga, J.V.; Siegmund, O.H.W. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Feller, W.B. [Nova Scientific Inc., 10 Picker Road, Sturbridge, MA 01566 (United States); Lehmann, E. [Paul Scherrer Institute, CH-5232 Villigen (Switzerland); Butler, L.G. [Louisiana State University, Baton Rouge, LA 70803 (United States); Dawson, M. [Helmholtz Centre Berlin for Materials and Energy (Germany)

    2011-10-01

    The improved collimation and intensity of thermal and cold neutron beamlines combined with recent advances in neutron imaging devices enable high-resolution neutron radiography and microtomography, which can provide information on the internal structure of objects not achievable with conventional X-ray imaging techniques. Neutron detection efficiency, spatial and temporal resolution (important for the studies of dynamic processes) and low background count rate are among the crucial parameters defining the quality of radiographic images and tomographic reconstructions. The unique capabilities of neutron counting detectors with neutron-sensitive microchannel plates (MCPs) and with Timepix CMOS readouts providing high neutron detection efficiency ({approx}70% for cold neutrons), spatial resolutions ranging from 15 to 55 {mu}m and a temporal resolution of {approx}1 {mu}s-combined with the virtual absence of readout noise-make these devices very attractive for high-resolution microtomography. In this paper we demonstrate the capabilities of an MCP-Timepix detection system applied to microtomographic imaging, performed at the ICON cold neutron facility of the Paul Scherrer Institute. The high resolution and the absence of readout noise enable accurate reconstruction of texture in a relatively opaque wood sample, differentiation of internal tissues of a fly and imaging of individual {approx}400 {mu}m grains in an organic powder encapsulated in a {approx}700 {mu}m thick metal casing.

  8. Neutrons in the moon. [neutron flux and production rate calculations

    Science.gov (United States)

    Kornblum, J. J.; Fireman, E. L.; Levine, M.; Aronson, A.

    1973-01-01

    Neutron fluxes for energies between 15 MeV and thermal at depths of 0 to 300 g/sq cm in the moon are calculated by the discrete ordinate mathod with the ANISN code. With the energy spectrum of Lingenfelter et al. (1972). A total neutron-production rate for the moon of 26 plus or minus neutrons/sq cm sec is determined from the Ar-37 activity measurements in the Apollo 16 drill string, which are found to have a depth dependence in accordance with a neutron source function that decreases exponentially with an attenuation length of 155 g/sq cm.

  9. Are there good probes for the di-neutron correlation in light neutron-rich nuclei?

    CERN Document Server

    Hagino, K

    2015-01-01

    The di-neutron correlation is a spatial correlation with which two valence neutrons are located at a similar position inside a nucleus. We discuss possible experimental probes for the di-neutron correlation. This includes the Coulomb breakup and the pair transfer reactions of neutron-rich nuclei, and the direct two-neutron decays of nuclei beyond the neutron drip-line.

  10. Neutrons are flying

    CERN Multimedia

    2000-01-01

    View of the n_TOF tube with members of the design and construction team of the facility(from left to right: R. Magnin/LHC, E. Radermacher/EP, P. Cennini/EP and R. Cappi/PS). A new experimental facility was inaugurated at CERN on Wednesday 8 November. The neutron Time Of Flight (n_TOF) facility received its first protons from the PS at 10:55. With an intensity of 1 x 1011 protons per cycle on the n_TOF target, an intense neutron beam has been produced at CERN for the first time, opening the door to many new avenues of research including, for example, neutron induced cross-section measurements. The facility is an offspring of the work by Carlo Rubbia and his group on the novel idea of an Energy Amplifier. The basic idea was successfully tested at the PS with the FEAT experiment and later with the TARC experiment, where the feasibility of transmutation of long-lived products by Adiabatic Resonance Crossing (ARC) was confirmed. This led to the possibility of radio-isotope production for medical applications, fo...

  11. Neutron instrumentation for biology

    Energy Technology Data Exchange (ETDEWEB)

    Mason, S.A. [Institut Laue-Langevin, Grenoble (France)

    1994-12-31

    In the October 1994 round of proposals at the ILL, the external biology review sub- committee was asked to allocate neutron beam time to a wide range of experiments, on almost half the total number of scheduled neutron instruments: on 3 diffractometers, on 3 small angle scattering instruments, and on some 6 inelastic scattering spectrometers. In the 3.5 years since the temporary reactor shutdown, the ILL`s management structure has been optimized, budgets and staff have been trimmed, the ILL reactor has been re-built, and many of the instruments up-graded, many powerful (mainly Unix) workstations have been introduced, and the neighboring European Synchrotron Radiation Facility has established itself as the leading synchrotron radiation source and has started its official user program. The ILL reactor remains the world`s most intense dedicated neutron source. In this challenging context, it is of interest to review briefly the park of ILL instruments used to study the structure and energetics of small and large biological systems. A brief summary will be made of each class of experiments actually proposed in the latest ILL proposal round.

  12. Separation Sr and Ba From Fission Products Using Sr-spec Resin Column

    Institute of Scientific and Technical Information of China (English)

    WANG; Xiu-feng

    2013-01-01

    Sr and Ba are the IIA group elements,with the same outer electronic structure,and the very similar properties,so separation of the two elements becomes very difficult.The traditional separation method of Sr and Ba in fission products is repeated precipitation of BaCl2·H2O in hydrochloric acid-ether medium.Four times repeated precipitation steps are needed to ensure the decontamination factor of Sr to be better

  13. Development of a quasi-monoenergetic neutron field using the 7Li(p,n)7Be reaction in the energy range from 250 to 390 MeV at RCNP.

    Science.gov (United States)

    Taniguchi, S; Nakao, N; Nakamura, T; Yashima, H; Iwamoto, Y; Satoh, D; Nakane, Y; Nakashima, H; Itoga, T; Tamii, A; Hatanaka, K

    2007-01-01

    A quasi-monoenergetic neutron field using the (7)Li(p,n)(7)Be reaction has been developed at the ring cyclotron facility at the Research Center for Nuclear Physics (RCNP), Osaka University. Neutrons were generated from a 10-mm-thick Li target injected by 250, 350 and 392 MeV protons and neutrons produced at 0 degrees were extracted into the time-of-flight (TOF) room of 100-m length through the concrete collimator of 10 x 12 cm aperture and 150 cm thickness. The neutron energy spectra were measured by a 12.7-cm diam x 12.7-cm long NE213 organic liquid scintillator using the TOF method. The peak neutron fluence was 1.94 x 10(10), 1.07 x 10(10) and 1.50 x 10(10) n sr(-1) per muC of 250, 350 and 392 MeV protons, respectively. The neutron spectra generated from various thick (stopping length) targets of carbon, aluminium, iron and lead, bombarded by 250 and 350 MeV protons, were also measured with the TOF method. Although these measurements were performed to obtain thick target neutron yields, they are also used as a continuous energy neutron field. These neutron fields are very useful for characterising neutron detectors, measuring neutron cross sections, testing irradiation effects for various materials and performing neutron shielding experiments.

  14. Euratom Neutron Radiography Working Group

    DEFF Research Database (Denmark)

    Domanus, Joseph Czeslaw

    1986-01-01

    In 1979 a Neutron Radiography Working Group (NRWG) was constituted within Buratom with the participation of all centers within the European Community at which neutron facilities were available. The main purpose of NRWG was to standardize methods and procedures used in neutron radiography of nuclear...... reactor fuel as well as establish standards for radiographic image quality of neutron radiographs. The NRWG meets once a year in each of the neutron radiography centers to review the progress made and draw plans for the future. Besides, ad-hoc sub-groups or. different topics within the field of neutron...... radiography are constituted. This paper reviews the activities and achievements of the NRWG and its sub-groups....

  15. Neutron background estimates in GESA

    Directory of Open Access Journals (Sweden)

    Fernandes A.C.

    2014-01-01

    Full Text Available The SIMPLE project looks for nuclear recoil events generated by rare dark matter scattering interactions. Nuclear recoils are also produced by more prevalent cosmogenic neutron interactions. While the rock overburden shields against (μ,n neutrons to below 10−8 cm−2 s−1, it itself contributes via radio-impurities. Additional shielding of these is similar, both suppressing and contributing neutrons. We report on the Monte Carlo (MCNP estimation of the on-detector neutron backgrounds for the SIMPLE experiment located in the GESA facility of the Laboratoire Souterrain à Bas Bruit, and its use in defining additional shielding for measurements which have led to a reduction in the extrinsic neutron background to ∼ 5 × 10−3 evts/kgd. The calculated event rate induced by the neutron background is ∼ 0,3 evts/kgd, with a dominant contribution from the detector container.

  16. Joseph C. Risser Sr., 1892–1982

    OpenAIRE

    Manring, M. M.; Calhoun, Jason

    2009-01-01

    This biographical sketch of Joseph C. Risser Sr. corresponds to the historic text, The Classic: The Iliac Apophysis: An Invaluable Sign in the Management of Scoliosis, available at DOI 10.1007/s11999-009-1096-z.

  17. Neutron Spectra, Fluence and Dose Rates from Bare and Moderated Cf-252 Sources

    Energy Technology Data Exchange (ETDEWEB)

    Radev, Radoslav P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-04-01

    A new, stronger 252Cf source (serial number SR-CF-3050-OR) was obtained from Oak Ridge National Laboratory (ORNL) in 2014 to supplement the existing 252Cf sources which had significantly decayed. A new instrument positioning track system was designed and installed by Hopewell Designs, Inc. in 2011. The neutron field from the new, stronger 252Cf source in the modified calibration environment needed to be characterized as well as the modified neutron fields produced by the new source and seven different neutron moderators. Comprehensive information about our 252Cf source, its origin, production, and isotopic content and decay characteristics needed to be compiled as well. This technical report is intended to address these issues.

  18. Beta-decay properties of neutron-rich medium-mass nuclei

    Science.gov (United States)

    Sarriguren, Pedro

    2016-06-01

    β-decay properties of even-even and odd-A neutron-rich Ge, Se, Kr, Sr, Zr, Mo, Ru, and Pd isotopes involved in the astrophysical rapid neutron capture process are studied within a microscopic proton-neutron quasiparticle random-phase approximation. The underlying mean field is based on a self-consistent Skyrme Hartree-Fock + BCS calculation that includes deformation as a key ingredient. The isotopic evolution of the various nuclear equilibrium shapes and the corresponding charge radii are investigated in all the isotopic chains. The energy distributions of the Gamow-Teller strength, as well as the β-decay half-lives are discussed and compared with the available experimental information. It is shown that nuclear deformation plays a significant role in the description of the decay properties in this mass region. Reliable predictions of the strength distributions are essential to evaluate decay rates in astrophysical scenarios.

  19. Neutron Imaging by Boric Acid

    CERN Document Server

    Cardone, Fabio; Perconti, Walter; Petrucci, Andrea; Rosada, Alberto

    2013-01-01

    In this paper a new type of passive neutron detector based on the already existing one, CR39, is described. Its operation was verified by three different neutron sources: an Americium-Beryllium (Am241-Be) source; a TRIGA type nuclear reactor; and a fast neutron reactor called TAPIRO. The obtained results, reported here, positively confirm its operation and the accountability of the new developed detecting technique.

  20. Radiogenic and stable Sr isotope ratios (87Sr/86Sr, δ88/86Sr) as tracers of riverine cation sources and biogeochemical cycling in the Milford Sound region of Fiordland, New Zealand

    Science.gov (United States)

    Andrews, M. Grace; Jacobson, Andrew D.; Lehn, Gregory O.; Horton, Travis W.; Craw, Dave

    2016-01-01

    This study reports radiogenic Sr isotope ratios (87Sr/86Sr), stable Sr isotope ratios (δ88/86Sr), and major ion concentrations for river, rock, sediment, soil, and plant samples collected from the Cleddau and Hollyford catchments in the Milford Sound region of Fiordland, New Zealand. The catchments primarily drain gabbro, but some tributaries access limestone and volcanogenic sediments. The goal of the study was to understand controls on riverine δ88/86Sr values in a landscape with multiple factors that may influence chemical weathering, including dense vegetation, high rainfall, and abundant, freshly-eroded Holocene fluvio-glacial and landslide debris. Rivers draining gabbro have higher δ88/86Sr values than bedrock, by as much as ∼0.14‰, and the δ88/86Sr values strongly correlate with molar Ca/Sr ratios (R2 = 0.69). Leaching of rocks and sediment reveals no evidence for the preferential dissolution of minerals having high δ88/86Sr values and Ca/Sr ratios. In-stream Sr isotope fractionation seems unlikely because comparison against 87Sr/86Sr and Ca/Sr ratios demonstrates that riverine δ88/86Sr values conservatively trace water-mass mixing. The riverine data are best explained by the input of soil water, which is distinct from potential bedrock end-members (i.e., silicates and carbonates) based on δ88/86Sr but indistinguishable in terms of Ca/Sr and 87Sr/86Sr. While strontium isotope fractionation during secondary mineral formation and pedogenesis is possible, clay mineral formation is minor and most soils are poorly developed. Instead, soil water δ88/86Sr values more likely reflect plant uptake. Plant samples yielded a wide range of δ88/86Sr values, but on average, they are lower than those for bedrock, consistent with the expectation that plants preferentially incorporate lighter Sr isotopes. Mass-balance constraints, together with 87Sr/86Sr ratios, indicate that soil water δ88/86Sr values are ∼0.30‰ higher than bedrock δ88/86Sr values, and