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Sample records for nuclear g-factor measurements

  1. Towards high precision measurements of nuclear g-factors for the Be isotopes

    NASA Astrophysics Data System (ADS)

    Takamine, A.; Wada, M.; Okada, K.; Ito, Y.; Schury, P.; Arai, F.; Katayama, I.; Imamura, K.; Ichikawa, Y.; Ueno, H.; Wollnik, H.; Schuessler, H. A.

    2016-06-01

    We describe the present status of future high-precision measurements of nuclear g-factors utilizing laser-microwave double and laser-microwave-rf triple resonance methods for online-trapped, laser-cooled radioactive beryllium isotope ions. These methods have applicability to other suitably chosen isotopes and for beryllium show promise in deducing the hyperfine anomaly of 11Be with a sufficiently high precision to study the nuclear magnetization distribution of this one-neutron halo nucleus in a nuclear-model-independent manner.

  2. Nuclear g-factor measurements of the (9/2){sup -} and (21/2){sup -} isomeric states in {sup 173}Ta

    SciTech Connect

    Thakur, P.; Kumar, V.; Bhati, A. K.; Bedi, S. C.; Singh, R. P.; Bhowmik, R. K.; Stuchbery, A. E.

    2006-09-15

    The nuclear g-factors of the one-quasiparticle isomeric state (9/2){sup -} at 165.8 keV and the three-quasiparticle isomeric state (21/2){sup -} at 1713.2 keV in {sup 173}Ta nuclei have been measured using the time differential perturbed angular distribution technique. The nuclear reaction {sup 165}Ho({sup 12}C, 4n{gamma}){sup 173}Ta was used to populate these isomeric states, and the recoiling {sup 173}Ta nuclei were implanted into a thick tantalum backing in the presence of a 7.04(4) kG external magnetic field. The measured value g((9/2){sup -}) = +0.591(18) shows that the (9/2){sup -} isomeric state is not a pure single-particle state but may have a collective contribution due to the octupole excitation of the core. Based on the measured value g((21/2){sup -}) = + 0.620(15) and multi-quasiparticle calculations, the (21/2){sup -} isomeric state is assigned a mixed configuration: {pi}{sup 3}((9/2){sup -}[514], (7/2){sup +}[404] (5/2){sup +}[402]) (39%) and {pi}{sup 1}((7/2){sup +}[404])(multiply-in-circle sign) {nu}{sup 2}((7/2){sup -}[514], (7/2){sup +}[633]) (61%)

  3. Nuclear g-factor measurement for the low-lying state in ^109Rh using On-line TDPAC technique and RF-IGISOL technique

    NASA Astrophysics Data System (ADS)

    Miyashita, Yuji; Ouchi, Hiroyuki; Izumi, Sayaka; Sasaki, Ayako; Sato, Nozomi; Tateoka, Miki; Hoshino, Sayo; Nagano, Tetsuya; Yamashita, Wataru; Yamazaki, Akiyoshi; Shimada, Kenzi; Ishida, Takashi; Wakui, Takashi; Shinozuka, Tsutomu; Tanigaki, Minoru

    2009-10-01

    To extend the studies on neutron-rich nuclei, we have developed an RF-IGISOL technique, which is combination of the gas catcher technique and the electrical field guiding technique with a large volume gas cell. As the first step to such approach, we are planning and trying the systematic measurement of g-factor in the neutron rich nuclei extracted as an radioactive beam from our RF-IGISOL at Tohoku University. The g-factor measurement for the low-lying state of ^109Rh (Ex = 225.98 keV, T1/2 = 1.66 μs) is the first on-line experiment with our RF-IGISOL system. The g-factor for this state has been determined to be g = 0.78 ^+0.17-0.03 μN by the on-line TDPAC method. In this contribution, the details of experimental results will be reported.

  4. Nuclear-polarization correction to the bound-electron g factor in heavy hydrogenlike ions.

    PubMed

    Nefiodov, A V; Plunien, G; Soff, G

    2002-08-19

    The influence of nuclear polarization on the bound-electron g factor in heavy hydrogenlike ions is investigated. Numerical calculations are performed for the K- and L-shell electrons taking into account the dominant virtual nuclear excitations. This determines the ultimate limit for tests of QED utilizing measurements of the bound-electron g factor in highly charged ions. PMID:12190457

  5. Nuclear and QED corrections to the bound-electron g factor

    NASA Astrophysics Data System (ADS)

    Zatorski, Jacek; Oreshkina, Natalia S.; Keitel, Christoph H.; Harman, Zoltán

    2012-06-01

    We calculate nuclear shape and quantum electrodynamic corrections to the g factor of a bound electron [1,2]. These theoretical studies are motivated by the current improvement of experimental possibilities: on the one hand, in a recent Penning trap measurement [2], the g factor of ^28Si^13+ has been determined with an unprecedented 5 .10-10 relative uncertainty. A novel experimental technique will further improve accuracy to the 10-11 level. On the other hand, experiments with ions as heavy as ^238U^91+ will be performed soon at the HITRAP-FAIR facility. For such heavy ions, nuclear effects play an important role. The leading relativistic nuclear deformation correction has been derived analytically and also its influence on one-loop quantum electrodynamic terms has been evaluated. We present results for medium- and high-Z hydrogenlike ions, which become significant already for mid-Z ions, and for very heavy elements it even reaches the 10-6 level, as we show in [1].[4pt] [1] J. Zatorski, N. S. Oreshkina, C. H. Keitel, and Z. Harman, Phys. Rev. Lett., in press; arXiv:1110.3330 [2] S. Sturm, A. Wagner, B. Schabinger, J. Zatorski, et al., Phys. Rev. Lett. 107, 023002 (2011).

  6. g-factor measurements of isomeric states in 174W

    NASA Astrophysics Data System (ADS)

    Rocchini, M.; Nannini, A.; Benzoni, G.; Melon, B.; John, P. R.; Ur, C. A.; Avigo, R.; Bazzacco, D.; Blasi, N.; Bocchi, G.; Bottoni, S.; Bracco, A.; Camera, F.; Ceruti, S.; Crespi, F. C. L.; Georgiev, G.; Giaz, A.; Gottardo, A.; Leoni, S.; Menegazzo, R.; Mengoni, D.; Michelagnoli, C.; Million, B.; Modamio, V.; Morales, A. I.; Napoli, D. R.; Ottanelli, M.; Pellegri, L.; Perego, A.; Valiente-Dobon, J. J.; Wieland, O.

    2016-05-01

    The experimental setup GAMIPE used for gyro magnetic factor measurements at Laboratori Nazionali di Legnaro and a recent experimental work regarding K-isomers in 174W are described. Aim of the experiment is to study the detailed structure of the isomeric states wave functions, by the measurement of the magnetic dipole moments. This piece of information can provide interesting hints for theoretical models. Preliminary results concerning the population of the isomers of interest and half-lives are presented.

  7. Measurement of the anomalous neutron orbital g factor in /sup 190//sup m/Os

    SciTech Connect

    Beck, R.; Eder, R.; Hagn, E.; Zech, E.

    1987-12-28

    The magnetic moment of /sup 190//sup m/Os (I/sup ..pi../ = 10/sup -/; T/sub 1/2/ = 9.9 min; E = 1705 keV configuration chemically bondn/sub 1/9/2(505)n/sub 2/11/2(615)>/sub 10-/ has been measured with the new technique of reorientation--nuclear-orientation. As the spin contributions of the two neutrons to the magnetic moment cancel almost completely, it is possible to determine the anomalous neutron orbital g factor directly. The result, -0.12less than or equal todeltag/sub 1/(n)less than or equal to0.07 (90% confidence level) tends to be larger than deltag/sub 1/(n)approx. =-0.05 adopted up to now.

  8. Single particle signatures in high-spin, quasicontinuum, states in {sup 193,194}Hg from g-factor measurements.

    SciTech Connect

    Weissman, L.; Mayer, R. H.; Kumbartzki, G.; Benczer-Koller, N.; Broude, C.; Cizewski, J. A.; Hass, M.; Holden, J.; Janssens, R. V. F.; Lauritsen, T.; Lee, I. Y.; Macchiavelli, A. O.; McNabb, D. P.; Satteson, M.; Physics; Weizmann Inst. of Science; Rutgers Univ.; LBNL

    1999-01-14

    The average g factors of high spin, high-excitation energy, quasicontinuum structures in {sup 194,193}Hg were measured by observing the precessions of the angular distributions of {gamma}-ray transitions in several normal-deformation bands that coalesce in the decay of the entry distribution of states. The average g factors of the states leading to the three main bands in the {sup 193,194}Hg isotopes were: {l_angle}g({sup 193}Hg){r_angle}=+0.19(1) and {l_angle}g({sup 194}Hg){r_angle}=+0.26(1), respectively. These average g factors are smaller than the average of the g factors of the high energy states in the three superdeformed bands of {sup 194}Hg, {l_angle}g(SD; {sup 194}Hg){r_angle}=+0.41(8). While the nucleus in the superdeformed well behaves like a rigid rotor, the present results demonstrate the important role played by multiple, quasiparticle neutron configurations in the structure of normal-deformation, highly-excited nuclear states.

  9. Recoil in vacuum for Te ions: Calibration, models, and applications to radioactive-beam g-factor measurements

    SciTech Connect

    Stuchbery, A. E.; Stone, N. J.

    2007-09-15

    In the light of new g factor results for the stable isotopes between {sup 122}Te and {sup 130}Te, the calibration and modeling of the recoil-in-vacuum (RIV) interaction for Te ions is reexamined, and the recent radioactive-beam g factor measurement on {sup 132}Te by the RIV technique is reevaluated. The implications for further RIV g-factor measurements in the {sup 132}Sn region are discussed.

  10. New reaction chamber for transient field g-factor measurements with radioactive ion beams

    NASA Astrophysics Data System (ADS)

    Illana, A.; Perea, A.; Nácher, E.; Orlandi, R.; Jungclaus, A.

    2015-06-01

    A new reaction chamber has been designed and constructed to measure g-factors of short-lived excited states using the Transient Field technique in combination with Coulomb excitation in inverse kinematics. In this paper we will discuss several important aspects which have to be considered in order to successfully carry out this type of measurement with radioactive ion beams, instead of the stable beams used in a wide range of experiments in the past. The technical solutions to the problems arising from the use of such radioactive beams will be exposed in detail and the first successful experiment using the new chamber in combination with MINIBALL cluster detectors at REX-ISOLDE (CERN) will be reported on.

  11. Lifetime and g-factor measurements of excited states using Coulomb excitation and alpha transfer reactions

    NASA Astrophysics Data System (ADS)

    Guevara, Z. E.; Torres, D. A.

    2016-07-01

    In this contribution the challenges in the use of a setup to simultaneously measure lifetimes and g-factor values will be presented. The simultaneous use of the transient field technique and the Doppler Shift Attenuation Method, to measure magnetic moments and lifetimes respectively, allows to obtain a complete characterization of the currents of nucleons and the deformation in excited states close to the ground state. The technique is at the moment limited to Coulomb excitation and alpha-transfer reactions, what opens an interesting perspective to consider this type of experiments with radioactive beams. The use of deep-inelastic and fusion-evaporation reactions will be discussed. An example of a setup that makes use of a beam of 106Cd to study excited states of 110Sn and the beam nuclei itself will be presented.

  12. Measuring g factors of 41+ and 61+ states in even-even nuclei with 80

    NASA Astrophysics Data System (ADS)

    Torres, Diego; Benczer-Koller, N.; Kumbartzki, G.; Gürdal, G.; Sharon, Y. Y.; Zamick, L.; Speidel, K.-H.; Ilie, G.; Heinz, A.; Ahn, T.; Werner, V.; Robinson, S. J. Q.

    2011-10-01

    The measurement of g factors of the low lying excited states in even-even nuclei with lifetimes of the order of 1 to 50 picoseconds presents challenging questions for both theory and experiment. The experimental determination of accurate g factor values uses the transient field technique in inverse kinematics and requires an understanding of the reaction mechanism used to populate the final states. So far, the main method of excitation has been Coulomb excitation. More recently, alpha transfer from a 12C target to selected beams made it possible to populate states in nuclei not available as stable beams. This method has been successful for lighter nuclei up to A ~70. A comparison between Coulomb excitation and alpha transfer reactions will be presented. The experiments used the Tandem at the Wright Nuclear Structure Laboratory at Yale University. Preliminary results for the 100Pd, 96Ru and 86Sr nuclei will be presented. Experimental challenges for future experiments will be discussed. Supported in part by the DOE and the NSF.

  13. Optical detection of anisotropic g-factor and nuclear spin polarization in a single CdTe quantum well

    NASA Astrophysics Data System (ADS)

    Yan, Li-Ping; Kurosawa, Masahiro; Hsu, Wei-Ting; Chang, Wen-Hao; Adachi, Satoru

    2015-03-01

    Longitudinal and in-plane electron g-factors, and a nuclear spin polarization (NSP) have been evaluated precisely in a CdTe/Cd0.85Mg0.15Te single quantum well by using the time-resolved Kerr rotation and double lock-in detection techniques. Resident electron spin polarization (RESP) was formed via the negative trion formation and recombination, and RESP gave rise to NSP in an oblique magnetic field configuration. We observed the effective nuclear field of a few mT which was weak compared with that in III-V semiconductor nanostructures as expected, but the nuclear field can be converted to the maximal NSP of 12% in Faraday geometry.

  14. Low-energy structure of the even-A {sup 96-104}Ru isotopes via g-factor measurements

    SciTech Connect

    Taylor, M. J.; Bentley, M. A.; Guerdal, G.; Kumbartzki, G.; Benczer-Koller, N.; Sharon, Y. Y.; Stuchbery, A. E.; Berant, Z.; Casperson, R. J.; Casten, R. F.; Heinz, A.; Ilie, G.; McCutchan, E. A.; Qian, J.; Werner, V.; Williams, E.; Winkler, R.; Luettke, R.; Shoraka, B.

    2011-04-15

    The transient-field-perturbed angular correlation technique was used with Coulomb excitation in inverse kinematics to perform a systematic measurement of the g factors of the first excited 2{sub 1}{sup +} states in the stable even-A isotopes {sup 96-104}Ru. The measurements have been made relative to one another under matched kinematic conditions and include a measurement of g(2{sub 1}{sup +})=+0.47(3) in {sup 96}Ru.

  15. New measurement of the {sup 68}Zn(4{sub 1}{sup +}) g factor combined with a reanalysis of previous data

    SciTech Connect

    Moschner, K.; Bernards, C.; Bettermann, L.; Speidel, K.-H.; Leske, J.; Bauer, C.; Moeller, T.; Honma, M.; Maier-Komor, P.; Muecher, D.

    2010-07-15

    We have remeasured and have redetermined the g factor for the 4{sub 1}{sup +} state in {sup 68}Zn following inconsistencies between earlier measurements and a recent result. We have reanalyzed several former measurements by applying an alternative analysis procedure, which allows for determining the precession effect separately for each gamma detector implying less uncertainties in the background subtraction for the relevant spectra. In addition, all measured g-factor and B(E2) data for the first 2{sup +} and 4{sup +} states in all stable even-A Zn isotopes and the radioactive {sup 62}Zn, are compared with new large-scale shell model calculations based on the most advanced effective interaction in the fpg-shell model space.

  16. First direct measurements of {bold {ital g}} factors of the three superdeformed bands of {sup 194}Hg

    SciTech Connect

    Mayer, R.H.; Kumbartzki, G.; Benczer-Koller, N.; Cizewski, J.A.; Holden, J.; McNabb, D.P.; Satteson, M.; Weissman, L.; Broude, C.; Hass, M.; Janssens, R.V.; Lauritsen, T.; Lee, I.Y.; Macchiavelli, A.O.

    1998-11-01

    The average {ital g} factors of the high-energy states of the three superdeformed bands in {sup 194}Hg were determined {ital directly} in a transient field experiment. The reaction {sup 150}Nd({sup 48}Ca,4n){sup 194}Hg at a beam energy of 203 MeV was used to provide recoiling reaction product nuclei with sufficient velocity to traverse a gadolinium ferromagnetic layer. The resulting {ital g} factors g(SD1)=0.36(10), g(SD2)=0.41(20), and g(SD3)=0.71(26) are in agreement with cranked Hartree-Fock calculations as well as with the picture of a rigid rotation for which g=Z/A. thinsp {copyright} {ital 1998} {ital The American Physical Society}

  17. Vanishing electron g factor and long-lived nuclear spin polarization in weakly strained nanohole-filled GaAs/AlGaAs quantum dots

    NASA Astrophysics Data System (ADS)

    Ulhaq, A.; Duan, Q.; Zallo, E.; Ding, F.; Schmidt, O. G.; Tartakovskii, A. I.; Skolnick, M. S.; Chekhovich, E. A.

    2016-04-01

    GaAs/AlGaAs quantum dots grown by in situ droplet etching and nanohole in-filling offer a combination of strong charge confinement, optical efficiency, and high spatial symmetry advantageous for polarization entanglement and spin-photon interface. Here, we study experimentally electron and nuclear spin properties of such dots. We find nearly vanishing electron g factors (ge<0.05 ), providing a potential route for electrically driven spin control schemes. Optical manipulation of the nuclear spin environment is demonstrated with nuclear spin polarization up to 65 % achieved. Nuclear magnetic resonance spectroscopy reveals two distinct types of quantum dots: with tensile and with compressive strain along the growth axis. In both types of dots, the magnitude of strain ɛb<0.02 % is nearly three orders of magnitude smaller than in self-assembled dots: On the one hand, this provides a route for eliminating a major source of electron spin decoherence arising from nuclear quadrupolar interactions, and on the other hand such strain is sufficient to suppress nuclear spin diffusion leading to a stable nuclear spin bath with nuclear spin lifetimes exceeding 500 s. The spin properties revealed in this work make this new type of quantum dot an attractive alternative to self-assembled dots for the applications in quantum information technologies.

  18. Magnetism of an excited self-conjugate nucleus: precise measurement of the g factor of the 2(1)(+) state in (24)Mg.

    PubMed

    Kusoglu, A; Stuchbery, A E; Georgiev, G; Brown, B A; Goasduff, A; Atanasova, L; Balabanski, D L; Bostan, M; Danchev, M; Detistov, P; Gladnishki, K A; Ljungvall, J; Matea, I; Radeck, D; Sotty, C; Stefan, I; Verney, D; Yordanov, D T

    2015-02-13

    A precise measurement of the g factor of the first-excited state in the self-conjugate (N=Z) nucleus (24)Mg is performed by a new time-differential recoil-in-vacuum method based on the hyperfine field of hydrogenlike ions. Theory predicts that the g factors of such states, in which protons and neutrons occupy the same orbits, should depart from 0.5 by a few percent due to configuration mixing and meson-exchange effects. The experimental result, g=0.538±0.013, is in excellent agreement with recent shell-model calculations and shows a departure from 0.5 by almost 3 standard deviations, thus achieving, for the first time, the precision and accuracy needed to test theory. Proof of the new method opens the way for wide applications including measurements of the magnetism of excited states of exotic nuclei produced as radioactive beams. PMID:25723214

  19. Measurements of the g-factors of the 2^+1 states in ^82Sr (25.3 d) and ^90Sr (28.8 y)

    NASA Astrophysics Data System (ADS)

    Rice, Samantha; Naimark, Samuel; Kumbartzki, Gerfried; Benczer-Koller, Noemie

    2012-10-01

    Magnetic moments and lifetimes of the 2^+1 states in ^84-88Sr isotopes were measured via the transient field technique and Coulomb excitation in inverse kinematics. The pending experiment will use ^78,86Kr beams from the TAMU Cyclotron to induce α-capture reactions on a ^12C target and produce the unstable isotopes of interest, ^82,90Sr. A new beam line, consisting of a target chamber, target cooling device, and external magnetic field, is being assembled at Rutgers. The ^12C target was evaporated on a substrate of gadolinium backed by a copper foil. A PIPS Si detector will detect α-particles exiting the target after the ^8Be breakup, and γ-rays will be detected by four Ge clover detectors. A digital data acquisition system will record α-γ coincidences. The angular correlation of the emitted γ-rays with respect to the beam direction will be determined from appropriate combinations of γ-ray intensities observed in various elements of the clover detectors. The measurement of the precession angles of the 2^+1 magnetic moments yield the experimental g-factors. The results will be compared to shell model calculations based on ^88Sr as a core nucleus.

  20. Measurements of the spin-orbit interaction and Landé g factor in a pure-phase InAs nanowire double quantum dot in the Pauli spin-blockade regime

    NASA Astrophysics Data System (ADS)

    Wang, Jiyin; Huang, Shaoyun; Lei, Zijin; Pan, Dong; Zhao, Jianhua; Xu, H. Q.

    2016-08-01

    We demonstrate direct measurements of the spin-orbit interaction and Landé g factors in a semiconductor nanowire double quantum dot. The device is made from a single-crystal pure-phase InAs nanowire on top of an array of finger gates on a Si/SiO2 substrate and the measurements are performed in the Pauli spin-blockade regime. It is found that the double quantum dot exhibits a large singlet-triplet energy splitting of ΔST ˜ 2.3 meV, a strong spin-orbit interaction of ΔSO ˜ 140 μeV, and a large and strongly level-dependent Landé g factor of ˜12.5. These results imply that single-crystal pure-phase InAs nanowires are desired semiconductor nanostructures for applications in quantum information technologies.

  1. Theory of Bound-Electron g Factor in Highly Charged Ions

    SciTech Connect

    Shabaev, V. M.; Glazov, D. A.; Plunien, G.; Volotka, A. V.

    2015-09-15

    The paper presents the current status of the theory of bound-electron g factor in highly charged ions. The calculations of the relativistic, quantum electrodynamics (QED), nuclear recoil, nuclear structure, and interelectronic-interaction corrections to the g factor are reviewed. Special attention is paid to tests of QED effects at strong coupling regime and determinations of the fundamental constants.

  2. Giant g-factors of natural impurities in synthetic quartz

    SciTech Connect

    Goryachev, Maxim; Farr, Warrick G.; Tobar, Michael E.

    2013-12-23

    We report the observation of g-factors of natural paramagnetic impurities in a pure synthetic quartz crystal at milli-Kelvin temperatures. Measurements are made by performing spectroscopy using multiple high-Q whispering gallery modes sustained in the crystal. Extreme sensitivity of the method at low temperatures allows the determination of natural residual impurities introduced during the crystal growth. We observe g-factors that significantly differ from integer multiples of the electron g-factor in vacuum, and with values of up to 7.6, which reveals much stronger coupling between impurities and the crystal lattice than in previous studies. Both substitutional and interstitial ions are proposed as candidates for the observed interactions.

  3. Magnetic Frustration from Nonuniform g-factors

    NASA Astrophysics Data System (ADS)

    Yin, Weiguo

    Frustrated magnets are commonly known as materials in which localized magnetic moments, or spins, interact through competing exchange interactions that cannot be simultaneously satisfied. Here we show that even when the exchange interactions are fully cooperative, magnetic frustration can be induced by nonuniform Landé g factors, leading to a mutual interplay of typical ferromagnetic (FM) and antiferromagnetic (AF) features. This novel physics--exactly demonstrated in the one-dimensional Ising model with alternating g factors--provides new insight into the puzzling phenomenon that the magnetic susceptibility of many AF or FM materials is FM-like at low temperature but AF-like at high temperature. Furthermore, we found a unique magnetic-field-driven quantum critical point at which one half of the spins are frozen into a complete order and the other half are fully disordered. The present theory joins the recent intensive search for frustrated magnets beyond the ``standard model'' of condensed matter physics. It could broaden our understanding and design of exotic magnetic behaviors such as spin ice, spin glass, and spin liquid that are essential to quantum computing, spintronics, and high-temperature superconductivity Work supported by U.S. Department of Energy, Office of Basic Energy Science, under Contract No. DE-AC02-98CH10886.

  4. g factor of the first 2+ state in 164Yb

    SciTech Connect

    Z. Berant; A. Wolf et al.

    2004-03-17

    The g factor of the first excited 2+ state of 164Yb was measured by perturbed gamma-gamma angular correlation in an external static magnetic field of 5.55T. The result g(2+)=0.32(5), extends the systematics for Yb isotopes down to N=94. The behavior of known experimental values of g(2+) vs N for all isotopic chains Ba to Pt is discussed.

  5. Particle-rotor versus particle-vibration features in g factors of 111Cd and 113Cd

    NASA Astrophysics Data System (ADS)

    Stuchbery, A. E.; Chamoli, S. K.; Kibédi, T.

    2016-03-01

    The emergence and evolution of collective excitations in complex nuclei remains a central problem in the quest to understand the nuclear many-body problem. Nuclear quadrupole collectivity is usually investigated via electric quadrupole observables. Here, however, we measure the g factors of low-excitation states in 111Cd and 113Cd and show that they are sensitive to the nature of the collectivity in these nuclei in ways that the electric quadrupole observables are not. The particle-vibration model, which assumes spherical core excitations, cannot explain the g factors, whereas a particle-rotor model with a small, nonzero core deformation does. The contrast of the two models is made stark by the fact that they begin from the same limiting g -factor values: It is shown that when an odd nucleon occupies a spherical orbit with angular momentum j =1 /2 , or a deformed orbit with j =1 /2 parentage, the particle-vibration model and the particle-rotor model both reduce to the same g -factor value in their respective limits of zero particle-vibration coupling or zero deformation.

  6. Average g-Factors of Anisotropic Polycrystalline Samples

    SciTech Connect

    Fishman, Randy Scott; Miller, Joel S.

    2010-01-01

    Due to the lack of suitable single crystals, the average g-factor of anisotropic polycrystalline samples are commonly estimated from either the Curie-Weiss susceptibility or the saturation magnetization. We show that the average g-factor obtained from the Curie constant is always greater than or equal to the average g-factor obtained from the saturation magnetization. The average g-factors are equal only for a single crystal or an isotropic polycrystal. We review experimental results for several compounds containing the anisotropic cation [Fe(C5Me5)2]+ and propose an experiment to test this inequality using a compound with a spinless anion.

  7. Fresh nuclear fuel measurements at Ukrainian nuclear power plants

    SciTech Connect

    Kuzminski, Jozef; Ewing, Tom; Dickman, Debbie; Gavrilyuk, Victor; Drapey, Sergey; Kirischuk, Vladimir; Strilchuk, Nikolay

    2009-01-01

    In 2005, the Provisions on Nuclear Material Measurement System was enacted in Ukraine as an important regulatory driver to support international obligations in nuclear safeguards and nonproliferation. It defines key provisions and requirements for material measurement and measurement control programs to ensure the quality and reliability of measurement data within the framework of the State MC&A System. Implementing the Provisions requires establishing a number of measurement techniques for both fresh and spent nuclear fuel for various types of Ukrainian reactors. Our first efforts focused on measurements of fresh nuclear fuel from a WWR-1000 power reactor.

  8. Precision comparison of the g-factor of the proton and anti-proton

    NASA Astrophysics Data System (ADS)

    Disciacca, Jack

    2013-05-01

    We report the first measurement of the antiproton magnetic moment using a single antiproton. The magnetic moment in nuclear magnetons is μp /μN = - 2 . 792845 +/- 0 . 000012 , a 4.4 parts per million (ppm) measurement. This represents a factor of 680 improvement in precision over previous work using exotic atom spectroscopy, which has achieved a 3000 ppm precision and remained essentially unchanged in the past 20 years., Our measurement allows for an improved comparison of the proton and antiproton magnetic moments, yielding a result consistent with the prediction of charge, parity and time reversal symmetry. Following a proof of principle, 2.5 ppm measurement of the proton magnetic moment, the experiment was moved to CERN for the antiproton experiment. Initial work focused on catching, cooling and trapping a single antiproton from the 5 MeV beam at CERN's Antiproton Decelerator. Following this work, we undertook a magnetic moment measurement. The spin and cyclotron frequency are measured to determine the g-factor, g / 2 =fs /fc . Prospects for further improvement should be possible with single spin flip detection, similar to what was used to measure the electron magnetic moment - currently the most precisely measured property of a fundamental particle. The new antiproton magnetic moment measurement is likely a first step towards improved precision by an additional factor of 103 or 104 improvement, with a precision at the part per billion level.,, A. Kreissl, et al., Z. Phys. C: Part. Fields 37, 557 (1988).

  9. g factor of the 2{sub 1}{sup +} state of {sup 172}Hf

    SciTech Connect

    Berant, Z.; Wolf, A.; Oster, E.; Casperson, R. J.; Werner, V.; Heinz, A.; Casten, R. F.; Terry, J. R.; Winkler, R.; Williams, E.; Qian, J.; Schmidt, A.; Smith, M. K.; Ahn, T.; Gurdal, G.; McCutchan, E. A.; Brenner, D. S.; Beausang, C. W.; Regan, P. H.; Ross, T.

    2009-11-15

    The g factor of the 2{sub 1}{sup +} state of {sup 172}Hf was measured using the perturbed angular correlation technique in a static external magnetic field. The result, g(2{sub 1}{sup +})=0.25(5), is discussed in relation to the systematics of the previously reported g factors in the Hf isotopes and compared with the predictions of several models. An interesting outcome of the analysis presented in this paper is the agreement between the calculated g factors within the interacting boson approximation (IBA) and the results of a large-scale shell model calculation. This agreement supports the emphasis in the IBA on the valence space. The undershooting of the empirical g factors near midshell in both models suggests that they underestimate the role of the saturation of collectivity, which is explicitly incorporated into a phenomenological model that agrees better with the data.

  10. g-factor of the 2{sup+}{sub{1} state of {sup179}Hf.

    SciTech Connect

    Berant, Z.; Oster, E.; Wolf, A.; Casperson, R. J.; Werner, V.; McCutchan, E. A.

    2009-01-01

    The g factor of the 2{sub 1}{sup +} state of {sup 172}Hf was measured using the perturbed angular correlation technique in a static external magnetic field. The result, g(2{sub 1}{sup +}) = 0.25(5), is discussed in relation to the systematics of the previously reported g factors in the Hf isotopes and compared with the predictions of several models. An interesting outcome of the analysis presented in this paper is the agreement between the calculated g factors within the interacting boson approximation (IBA) and the results of a large-scale shell model calculation. This agreement supports the emphasis in the IBA on the valence space. The undershooting of the empirical g factors near midshell in both models suggests that they underestimate the role of the saturation of collectivity, which is explicitly incorporated into a phenomenological model that agrees better with the data.

  11. InAs 2DEGs:What's the g-factor?

    NASA Astrophysics Data System (ADS)

    McCombe, B. D.; Pakmehr, Mehdi; Khaetskii, A.; Chiatti, Olivio; Fischer, S. F.; Buchholz, S.; Heyn, C.; Hansen, W.; Cahay, M.; Newrock, R. S.; Bandari, Nikhil

    2014-03-01

    Interest in spin-orbit effects in semiconductors has led us to study the electron g-factor in quasi-2DEG InAs samples. We have made magneto-transport and -photoresponse (PR) measurements on InAs QW structures in magnetic fields up to 10 T. THz cyclotron resonance (CR) is manifested in PR as a resonant envelope of the amplitude of quantum oscillations, which show clear spin-splitting (for lower mobility samples) down 4T, while direct R_xx measurements show no spin-splitting up to 9T. R_xx oscillations in a higher mobility sample show well-resolved spin-splittings over a range of fields as does the PR. We have simulated the data with a theoretical expression for 2DEG SdH oscillations (coupled with CR resonant carrier heating for the PR) and extracted g-factors from fits. We also used a different (commonly used) method, SdH oscillations vs. tilt angle of the field to extract g-factors from the angle at which the SdH frequency doubles. We find very large g-factors from fits to R_xx and PR (14 - 20), but g-factors 2-3 times smaller for these same samples from tilted field experiments (close to estimated band g-factors). These results are discussed in terms of exchange effects. Support: NSF DMR 1008138 (Buffalo); NSF ECCE 1028483(Cincinnati); DFG Fi932/4-1(Berlin).

  12. The g-factor of the K = 25 isomer in /sup 182/Os

    SciTech Connect

    Alderson, A.; Broude, C.; Bruce, A.; Dafni, E.; Fallon, P.; Goldring, G.; Hass, M; Nyberg, J.; Roberts, J.; Sharpey-Schafer, J.; Sletten, G.; Twin, P.

    1988-01-01

    The g-factor of the K = I = 25, 120 ns isomer in /sup 182/Os has been measured by observing the angular precession of the decay /gamma/-rays in an external magnetic field. Our preliminary result is g = 0.46(5). Comparing this result to predictions based on experimental g-factors of single-particle Nilsson orbitals in this mass region suggests equal contributions of neutron and proton spin to the total spin of I = 25. An attempt has also been undertaken to measure the quadrupole moment of this level by observing the time-dependent quadrupole interaction pattern of Os nuclei recoiling into an Os single crystal. The analysis of the quadrupole moment measurement, as well as a more detailed analysis of the g-factor measurement, is now in progress. 7 refs., 2 figs.

  13. Nuclear symmetry energy at subnormal densities from measured nuclear masses

    SciTech Connect

    Liu Min; Wang Ning; Li Zhuxia; Zhang Fengshou

    2010-12-15

    The symmetry energy coefficients for nuclei with mass number A=20-250 are extracted from more than 2000 measured nuclear masses. With the semiempirical connection between the symmetry energy coefficients of finite nuclei and the nuclear symmetry energy at reference densities, we investigate the density dependence of the symmetry energy of nuclear matter at subnormal densities. The obtained results are compared with those extracted from other methods.

  14. Determination of g-factor in a quantum well channel with a strong Rashba effect

    SciTech Connect

    Choi, Won Young; Cheol Koo, Hyun; Chang, Joonyeon; Hoon Lee, Jung

    2014-05-07

    Using the Shubnikov−de Haas oscillation measurement, the g-factor of carriers in a strong Rashba system is observed. To determine g-factor of carriers in the InAs quantum well channel with a strong Rashba effect, the magnetic fields are simultaneously applied along the in-plane direction and the perpendicular direction. The perpendicular field drives the oscillation of conductance for measuring Rashba spin orbit interaction and the in-plane field parallel to the Rashba field interacts with Rashba effect and modifies the intrinsic Rashba parameter. The total field inside the channel is a combination of the Rashba field and the in-plane field, so the modification of Rashba parameter gives a g-factor value of ∼13 in our system.

  15. Measurement control administration for nuclear materials accountability

    SciTech Connect

    Rudy, C.R.

    1991-01-31

    In 1986 a measurement control program was instituted at Mound to ensure that measurement performance used for nuclear material accountability was properly monitored and documented. The organization and management of various aspects of the program are discussed. Accurate measurements are the basis of nuclear material accountability. The validity of the accountability values depends on the measurement results that are used to determine inventories, receipts, and shipments. With this measurement information, material balances are calculated to determine losses and gains of materials during a specific time period. Calculation of Inventory Differences (ID) are based on chemical or physical measurements of many items. The validity of each term is dependent on the component measurements. Thus, in Figure 1, the measured element weight of 17 g is dependent on the performance of the particular measurement system that was used. In this case, the measurement is performed using a passive gamma ray method with a calibration curve determined by measuring representative standards containing a range of special nuclear materials (Figure 2). One objective of a measurement control program is to monitor and verify the validity of the calibration curve (Figure 3). In 1986 Mound's Nuclear Materials Accountability (NMA) group instituted a formal measurement control program to ensure the validity of the numbers that comprise this equation and provide a measure of how well bulk materials can be controlled. Most measurements used for accountability are production measurements with their own quality assurance programs. In many cases a measurement control system is planned and maintained by the developers and operators of the particular measurement system with oversight by the management responsible for the results. 4 refs., 7 figs.

  16. Influence of ion movement in a particle trap on the bound electron g factor

    NASA Astrophysics Data System (ADS)

    Michel, Niklas; Zatorski, Jacek; Keitel, Christoph H.

    2015-11-01

    In the relativistic description of atomic systems in external fields, the total momentum and the external electric field couple to the angular momentum of the individual particles. Therefore, the motional state of an ion in a particle trap influences measurements of internal observables such as energy levels or the g factor. We calculate the resulting relativistic shift of the Larmor frequency and the corresponding g -factor correction for a bound electron in a hydrogenlike ion in the 1 S state due to the ion moving in a Penning trap and show that it is negligible at the current precision of measurements. We also show that the analogous energy shift for measurements with an ion in the ground state of a Paul trap vanishes in leading order.

  17. Superconducting quantum spin Hall systems with giant orbital g factors

    NASA Astrophysics Data System (ADS)

    Reinthaler, R. W.; Tkachov, G.; Hankiewicz, E. M.

    2015-10-01

    Topological aspects of superconductivity in quantum spin Hall systems (QSHSs) such as thin layers of three-dimensional topological insulators (TIs) or two-dimensional TIs are the focus of current research. Here, we describe a superconducting quantum spin Hall effect (quantum spin Hall system in proximity to an s -wave superconductor and in orbital in-plane magnetic fields), which is protected against elastic backscattering by combined time-reversal and particle-hole symmetry. This effect is characterized by spin-polarized edge states, which can be manipulated in weak magnetic fields due to a giant effective orbital g factor, allowing the generation of spin currents. The phenomenon provides a solution to the outstanding challenge of detecting the spin polarization of the edge states. Here we propose the detection of the edge polarization in a three-terminal junction using unusual transport properties of the superconducting quantum Hall effect: a nonmonotonic excess current and a zero-bias conductance peak splitting.

  18. Holdup measurement for nuclear fuel manufacturing plants

    SciTech Connect

    Zucker, M.S.; Degen, M.; Cohen, I.; Gody, A.; Summers, R.; Bisset, P.; Shaub, E.; Holody, D.

    1981-07-13

    The assay of nuclear material holdup in fuel manufacturing plants is a laborious but often necessary part of completing the material balance. A range of instruments, standards, and a methodology for assaying holdup has been developed. The objectives of holdup measurement are ascertaining the amount, distribution, and how firmly fixed the SNM is. The purposes are reconciliation of material unbalance during or after a manufacturing campaign or plant decommissioning, to decide security requirements, or whether further recovery efforts are justified.

  19. Antineutrinos from nuclear reactors: recent oscillation measurements

    NASA Astrophysics Data System (ADS)

    Dwyer, D. A.

    2015-02-01

    Nuclear reactors are the most intense man-made source of antineutrinos, providing a useful tool for the study of these particles. Oscillation due to the neutrino mixing angle {{θ }13} is revealed by the disappearance of reactor {{\\bar{ν }}e} over ˜km distances. Use of additional identical detectors located near nuclear reactors reduce systematic uncertainties related to reactor {{\\bar{ν }}e} emission and detector efficiency, significantly improving the sensitivity of oscillation measurements. The Double Chooz, RENO, and Daya Bay experiments set out in search of {{θ }13} using these techniques. All three experiments have recently observed reactor {{\\bar{ν }}e} disappearance, and have estimated values for {{θ }13} of 9.3◦ ± 2.1°, 9.2◦ ± 0.9°, and 8.7◦ ± 0.4° respectively. The energy-dependence of {{\\bar{ν }}e} disappearance has also allowed measurement of the effective neutrino mass difference, \\mid Δ mee2\\mid ≈ \\mid Δ m312\\mid . Comparison with \\mid Δ mμ μ 2\\mid ≈ \\mid Δ m322\\mid from accelerator {{ν }μ } measurements supports the three-flavor model of neutrino oscillation. The current generation of reactor {{\\bar{ν }}e} experiments are expected to reach ˜3% precision in both {{θ }13} and \\mid Δ mee2\\mid . Precise knowledge of these parameters aids interpretation of planned {{ν }μ } measurements, and allows future experiments to probe the neutrino mass hierarchy and possible CP-violation in neutrino oscillation. Absolute measurements of the energy spectra of {{\\bar{ν }}e} deviate from existing models of reactor emission, particularly in the range of 5-7 MeV.

  20. Electron g-factor anisotropy in GaAs/Al1-xGaxAs quantum wells of different symmetry

    NASA Astrophysics Data System (ADS)

    Nefyodov, Yu. A.; Shchepetilnikov, A. V.; Kukushkin, I. V.; Dietsche, W.; Schmult, S.

    2011-12-01

    The anisotropy of the electron g factor is investigated in symmetrically (SQW) and asymmetrically (AQW) doped 20-nm GaAs/AlGaAs quantum wells, grown in the [001] direction. Applied was the electrically detected electron spin resonance technique. The AQW demonstrates strong twofold in-plane g-factor anisotropy with the [110] and [11¯0] principal axes. This can be readily ascribed to the internal electric field asymmetry as caused by single-side doping. The SQW is shown to have 10 times as weak (but still detectable) anisotropy with the same principal axes. The linear (in the magnetic field) corrections to the g factor were also carefully measured. The â tensor of these corrections is shown to have at least three different nonzero components, namely, azzz, axxz, and ayyz.

  1. Neutron capture measurements for nuclear astrophysics

    NASA Astrophysics Data System (ADS)

    Reifarth, Rene

    2005-04-01

    Almost all of the heavy elements are produced via neutron capture reactions in a multitude of stellar production sites. The predictive power of the underlying stellar models is currently limited because they contain poorly constrained physics components such as convection, rotation or magnetic fields. Neutron captures measurements on heavy radioactive isotopes provide a unique opportunity to largely improve these physics components, and thereby address important questions of nuclear astrophysics. Such species are branch-points in the otherwise uniquely defined path of subsequent n-captures along the s-process path in the valley of stability. These branch points reveal themselves through unmistakable signatures recovered from pre-solar meteoritic grains that originate in individual element producing stars. Measurements on radioactive isotopes for neutron energies in the keV region represent a stringent challenge for further improvements of experimental techniques. This holds true for the neutron sources, the detection systems and the technology to handle radioactive material. Though the activation method or accelerator mass spectroscopy of the reaction products could be applied in a limited number of cases, Experimental facilities like DANCE at LANL, USA and n-TOF at CERN, Switzerland are addressing the need for such measurements on the basis of the more universal method of detecting the prompt capture gamma-rays, which is required for the application of neutron time-of-flight (TOF) techniques. With a strongly optimized neutron facility at the Rare Isotope Accelerator (RIA) isotopes with half-lives down to tens of days could be investigated, while present facilities require half-lives of a few hundred days. Recent neutron capture experiments on radioactive isotopes with relevance for nuclear astrophysics and possibilities for future experimental setups will be discussed during the talk.

  2. An experiment for the direct determination of the g-factor of a single proton in a Penning trap

    NASA Astrophysics Data System (ADS)

    Rodegheri, C. C.; Blaum, K.; Kracke, H.; Kreim, S.; Mooser, A.; Quint, W.; Ulmer, S.; Walz, J.

    2012-06-01

    A new apparatus has been designed that aims at a direct precision measurement of the g-factor of a single isolated proton or antiproton in a Penning trap. We present a thorough discussion on the trap design and a method for the experimental trap optimization using a single stored proton. A first attempt at the g-factor determination has been made in a section of the trap with a magnetic bottle. The Larmor frequency of the proton has been measured with a relative uncertainty of 1.8 × 10-6 and the magnetic moment has been determined with a relative uncertainty of 8.9 × 10-6. A g-factor of 5.585 696(50) has been obtained, which is in excellent agreement with previous measurements and predictions. Future experiments shall drive the spin-flip transition in a section of the trap with a homogeneous magnetic field. This has the potential to improve the precision of the measured g-factor of the proton and the antiproton by several orders of magnitude.

  3. Geochemical Controls on Nuclear Magnetic Resonance Measurements

    SciTech Connect

    Knight, Rosemary; Prasad, Manika; Keating, Kristina

    2003-11-11

    OAK-B135 Our research objectives are to determine, through an extensive set of laboratory experiments, the effect of the specific mineralogic form of iron and the effect of the distribution of iron on proton nuclear magnetic resonance (NMR) relaxation mechanisms. In the first nine months of this project, we have refined the experimental procedures to be used in the acquisition of the laboratory NMR data; have ordered, and conducted preliminary measurements on, the sand samples to be used in the experimental work; and have revised and completed the theoretical model to use in this project. Over the next year, our focus will be on completing the first phase of the experimental work where the form and distribution of the iron in the sands in varied.

  4. Weighted difference of g factors of light Li-like and H-like ions for an improved determination of the fine-structure constant

    NASA Astrophysics Data System (ADS)

    Yerokhin, V. A.; Berseneva, E.; Harman, Z.; Tupitsyn, I. I.; Keitel, C. H.

    2016-08-01

    A weighted difference of the g factors of the Li- and H-like ion of the same element is studied and optimized in order to maximize the cancelation of nuclear effects. To this end, a detailed theoretical investigation is performed for the finite nuclear size correction to the one-electron g factor, the one- and two-photon exchange effects, and the QED effects. The coefficients of the Z α expansion of these corrections are determined, which allows us to set up the optimal definition of the weighted difference. It is demonstrated that, for moderately light elements, such weighted difference is nearly free from uncertainties associated with nuclear effects and can be utilized to extract the fine-structure constant from bound-electron g -factor experiments with an accuracy competitive with or better than its current literature value.

  5. Large anisotropy of electron and hole g factors in infrared-emitting InAs/InAlGaAs self-assembled quantum dots

    NASA Astrophysics Data System (ADS)

    Belykh, V. V.; Yakovlev, D. R.; Schindler, J. J.; Zhukov, E. A.; Semina, M. A.; Yacob, M.; Reithmaier, J. P.; Benyoucef, M.; Bayer, M.

    2016-03-01

    A detailed study of the g -factor anisotropy of electrons and holes in InAs/In0.53Al0.24Ga0.23As self-assembled quantum dots emitting in the telecom spectral range of 1.5 -1.6 μ m (around 0.8 eV photon energy) is performed by time-resolved pump-probe ellipticity technique using a superconducting vector magnet. All components of the g -factor tensors are measured, including their spread in the quantum dot (QD) ensemble. Surprisingly, the electron g factor shows a large anisotropy changing from ge ,x=-1.63 to ge ,z=-2.52 between directions perpendicular and parallel to the dot growth axis, respectively, at an energy of 0.82 eV. The hole g -factor anisotropy at this energy is even stronger: | gh,x|=0.64 and | gh,z|=2.29 . On the other hand, the in-plane anisotropies of electron and hole g factors are small. The pronounced out-of-plane anisotropy is also observed for the spread of the g factors, determined from the spin dephasing time. The hole longitudinal g factors are described with a theoretical model that allows us to estimate the QD parameters. We find that the QD height-to-diameter ratio increases while the indium composition decreases with increasing QD emission energy.

  6. The Measurement of Nuclear War Attitudes: Methods and Concerns.

    ERIC Educational Resources Information Center

    Mayton, Daniel M., II

    Measures of adults' attitudes toward nuclear war are briefly discussed, and Mayton's Modified World Affairs Questionnaire (MWAQ) is described. The 23-item MWAQ was developed from Novak and Lerner's World Affairs Questionnaire, a nuclear war attitude measure by Mayton and Delamater, and related interview items by Jeffries. When the MWAQ was…

  7. The electron g factor in AlGaN/GaN quantum wells

    NASA Astrophysics Data System (ADS)

    Li, Ming; Feng, Zhi-Bo.; Fan, Libo; Zhao, Yilong; Han, Hongpei; Feng, Tuanhui

    2016-04-01

    Considering the Rashba and Zeeman effects, the effective Hamiltonian for electrons in AlGaN/GaN quantum wells (QWs) with the magnetic field is obtained, and the effective transverse and longitudinal g-factor (g⊥,//), are derived. The small anisotropy of the g factor in bulk wurtzite materials is clearly shown, while the anisotropy in QWs induced by the quantum confined effect is evident. Moreover, the average g factor (g*) depends greatly on the position of the origin along the growth axis (c axis). With increasing well thickness, both g⊥ and g// increase, and the g-factor anisotropy first decreases and then increases slowly. Results show the g-factor and its anisotropy in III-nitride QWs can be modulated by the well thickness, and they are greatly affected by the internal electric field and the quantum confined effect.

  8. Mapping the anisotropic Lande g-factor tensor of 1D GaAs holes in all 3 spatial directions

    NASA Astrophysics Data System (ADS)

    Hudson, Karina; Srinivasan, Ashwin; Wang, Qingwen; Yeoh, Lareine; Klochan, Oleh; Farrer, Ian; Ritchie, David; Hamilton, Alex

    2014-03-01

    We have studied the Zeeman splitting of 1D holes formed on a (100) GaAs/AlGaAs heterostructure on a single cooldown. The strong spin orbit coupling and 1D confinment give rise to a highly anisotropic spin splitting. By use of the high-symmetry (100) crystal, we eliminate the effects of crystal anisotropy on our measurements. In measuring the spin splitting as a function of angle between the wire and the applied magnetic field, we are able to identify the principle axes of the g-tensor. We show that the principle axes are defined by the potential confining the 1D holes, and are not affected by the crystal axes. We find that g∥⊥ g-factors parallel and perpendicular to the wire, and g⊥ refers to the g-factor perpendicular to the 2D well.

  9. Fifty years of nuclear fission: Nuclear data and measurements series

    SciTech Connect

    Lynn, J.E.

    1989-06-01

    This report is the written version of a colloquium first presented at Argonne National Laboratory in January 1989. The paper begins with an historical preamble about the events leading to the discovery of nuclear fission. This leads naturally to an account of early results and understanding of the fission phenomena. Some of the key concepts in the development of fission theory are then discussed. The main theme of this discussion is the topography of the fission barrier, in which the interplay of the liquid-drop model and nucleon shell effects lead to a wide range of fascinating phenomena encompassing metastable isomers, intermediate-structure effects in fission cross-sections, and large changes in fission product properties. It is shown how study of these changing effects and theoretical calculations of the potential energy of the deformed nucleus have led to broad qualitative understanding of the nature of the fission process. 54 refs., 35 figs.

  10. g-factor anisotropy in nanowire-based InAs quantum dots

    SciTech Connect

    D'Hollosy, Samuel; Fábián, Gábor; Baumgartner, Andreas; Schönenberger, Christian; Nygård, Jesper

    2013-12-04

    The determination and control of the electron g-factor in semiconductor quantum dots (QDs) are fundamental prerequisites in modern concepts of spintronics and spin-based quantum computation. We study the dependence of the g-factor on the orientation of an external magnetic field in quantum dots (QDs) formed between two metallic contacts on stacking fault free InAs nanowires. We extract the g-factor from the splitting of Kondo resonances and find that it varies continuously in the range between |g*| = 5 and 15.

  11. Electrical control of the sign of the g factor in a GaAs hole quantum point contact

    NASA Astrophysics Data System (ADS)

    Srinivasan, A.; Hudson, K. L.; Miserev, D.; Yeoh, L. A.; Klochan, O.; Muraki, K.; Hirayama, Y.; Sushkov, O. P.; Hamilton, A. R.

    2016-07-01

    Zeeman splitting of one-dimensional hole subbands is investigated in quantum point contacts fabricated on a (311)-oriented GaAs-AlGaAs heterostructure. Transport measurements can determine the magnitude of the g factor, but cannot usually determine the sign. Here we use a combination of tilted fields and a unique off-diagonal element in the hole g tensor to directly detect the sign of g*. We are able to tune not only the magnitude, but also the sign of the g factor by electrical means, which is of interest for spintronics applications. Furthermore, we show theoretically that the resulting behavior of g* can be explained by the momentum dependence of the spin-orbit interaction.

  12. g Factor of the 7- isomer in 126Sn and first observation of spin-alignment in relativistic fission

    NASA Astrophysics Data System (ADS)

    Ilie, G.; Neyens, G.; Simpson, G. S.; Jolie, J.; Blazhev, A.; Grawe, H.; Lozeva, R. L.; Vermeulen, N.; Atanasova, L.; Balabanski, D. L.; Becker, F.; Bednarczyk, P.; Brandau, C.; Caceres, L.; Chamoli, S. K.; Daugas, J. M.; Doornenbal, P.; Gerl, J.; Górska, M.; Grȩbosz, J.; Hass, M.; Ionescu-Bujor, M.; Jungclaus, A.; Kmiecik, M.; Kojouharov, I.; Kurz, N.; Maj, A.; Mallion, S.; Perru, O.; Pfützner, M.; Podolyák, Zs.; Prokopowicz, W.; De Rydt, M.; Saito, T. R.; Schaffner, H.; Turzó, K.; Walker, J.; Werner-Malento, E.; Wollersheim, H. J.

    2010-04-01

    We report on the g factor measurement of the isomeric 7 state (E=2219 keV, T1/2=5.9(8) μs) in the neutron-rich 126Sn nucleus. The nucleus was produced by the fission of a relativistic 238U beam and reaction products were selected by the FRS fragment separator at GSI. For the first time, spin-alignment was observed after relativistic fission. It was used to deduce the g factor of the 7 isomeric state, g(7)=-0.098(9), from the measured perturbed angular distribution of its γ decay using the RISING Cluster detectors. The observed value confirms the suggested ν(h11/2-1d3/2-1) dominant configuration, which has been proposed for the 7 isomers in neutron-rich Sn isotopes. The failure of the g factor additivity rule and the importance of core polarization evolution with increasing distance from the doubly-magic 132Sn is discussed. The first observation of 18(8)% of spin-alignment produced by the relativistic fission of a 238U beam paves the way to study moments of neutron-rich (sub-)microsecond isomers, which are difficult to align by other means.

  13. Slotted surface coil with reduced g-factor for SENSE imaging.

    PubMed

    Ocegueda, K; Rodriguez, A O

    2006-01-01

    A new coil design inspired on the slot-and-hole magnetron tube is proposed for SENSE imaging. To investigate its g-factor behaviour: an SNR formula was derived using the quasi-static approach, and combined with the ultimate g-factor formula to compute the ultimate-factor-g-vs-depth plots. A g-factor expression was derived for the circular coil using the same approach for comparison purposes. SNR-vs-depth profiles of an 4-slot coil showed an important improvement over the circular coil. The 4-slot coil g-factor can be up to 58.32% lower than that of a single circular-shaped coil. This improvement makes the slotted surface coil a good choice for SENSE imaging. PMID:17946922

  14. Measuring Neutrino Oscillations with Nuclear Reactors

    SciTech Connect

    McKeown, R. D.

    2007-10-26

    Since the first direct observations of antineutrino events by Reines and Cowan in the 1950's, nuclear reactors have been an important tool in the study of neutrino properties. More recently, the study of neutrino oscillations has been a very active area of research. The pioneering observation of oscillations by the KamLAND experiment has provided crucial information on the neutrino mixing matrix. New experiments to study the remaining unknown mixing angle are currently under development. These recent studies and potential future developments will be discussed.

  15. Hadronization measurements in cold nuclear matter

    SciTech Connect

    Dupre, Raphael

    2015-05-01

    Hadronization is the non-perturbative process of QCD by which partons become hadrons. It has been studied at high energies through various processes, we focus here on the experiments of lepto-production of hadrons in cold nuclear matter. By studying the dependence of observables to the atomic number of the target, these experimentscan give information on the dynamic of the hadronization at the femtometer scale. In particular, we will present preliminary results from JLab Hall B (CLAS collaboration), which give unprecedented statistical precision. Then, we will present results of a phenomenological study showing how HERMES data can be described with pure energyloss models.

  16. G-factors of hole bound states in spherically symmetric potentials in cubic semiconductors

    NASA Astrophysics Data System (ADS)

    Miserev, Dmitry; Sushkov, Oleg

    2016-03-01

    Holes in cubic semiconductors have effective spin 3/2 and very strong spin orbit interaction. Due to these factors properties of hole bound states are highly unusual. We consider a single hole bound by a spherically symmetric potential, this can be an acceptor or a spherically symmetric quantum dot. Linear response to an external magnetic field is characterized by the bound state Lande g-factor. We calculate analytically g-factors of all bound states.

  17. Assays to measure nuclear mechanics in interphase cells

    PubMed Central

    Isermann, Philipp; Davidson, Patricia M.; Sliz, Josiah D.

    2012-01-01

    The nucleus is the characteristic hallmark of all eukaryotic cells. The physical properties of the nucleus reflect important biological characteristics, such as chromatin organization or nuclear envelope composition; they can also directly affect cellular function, for example, when cells pass through narrow constrictions, where the stiff nucleus may present a limiting factor. We present two complementary techniques to probe the mechanical properties of the nucleus. In the first, nuclear stiffness relative to the surrounding cytoskeleton is inferred from induced nuclear deformations during strain application to cells on an elastic substrate. In the second approach, nuclear deformability is deduced from the transit time through a perfusion-based microfabricated device with constrictions smaller than the size of the nucleus. These complementary methods, which can be applied to measure nuclear stiffness in large numbers of living adherent or suspended cells, can help identify important changes in nuclear mechanics associated with disease or development. PMID:22968843

  18. Revealing the Atomic Site-Dependent g Factor within a Single Magnetic Molecule via the Extended Kondo Effect

    NASA Astrophysics Data System (ADS)

    Du, Shixuan

    Control over charge and spin states at the single molecule level is crucial not only for a fundamental understanding of charge and spin interactions but also represents a prerequisite for development of molecular electronics and spintronics. In this talk, I will talk about the extended spin distribution in space beyond the central Mn ion, and onto the non-magnetic constituent atoms of the MnPc molecule. This extended spin distribution results in an extended Kondo effect, which can be explained by spin polarization induced by symmetry breaking of the molecular framework, as confirmed by DFT calculations. Measuring the evolution of the Kondo splitting with applied magnetic fields at different atomic sites, we find a spatial variation of the g-factor within a single molecule for the first time. The existence of atomic site-dependent g-factors can be attributed to specific molecular orbitals distributed over the entire molecule. This work not only open up a new opportunity for quantum information recording, but also provide a new route to explore the internal electronic and spin structure of complex molecules, hard to achieve otherwise. (L. W. Liu et al., Phys. Rev. Lett. 2015, 114, 126601. In collaboration with Liwei Liu, Kai Yang, Yuhang Jiang, Li Gao, Qi Liu, Boqun Song, Wende Xiao, Haitao Zhou, Hongjun Gao in CAS, Min Ouyang in MU, and A.H. Castro Neto in SNU.) Revealing the Atomic Site-Dependent g Factor within a Single Magnetic Molecule via the Extended Kondo Effect.

  19. Effective mass and Landé g-factor in Si-MOSFETs near the critical density

    NASA Astrophysics Data System (ADS)

    Limouny, Lhoussine; El Kaaouachi, Abdelhamid; Liang, Chi-Te

    2014-02-01

    We analyze the electrical resistivity and conductivity of a dilute two-dimensional electron gas (2DEG) in a Si metal-oxide-semiconductor field-effect transistor. When a magnetic field is applied parallel to the plane of the 2DEG, a signature of complete spin polarization, as evidenced by the saturation of the resistivity, is observed. We measured the effective mass and the Landé g-factor near the metal-insulator transition (MIT) and found that the Landé g-factor remained almost constant and close to its value in bulk silicon. In contrast, we have observed a sharp increase in the effective mass near the critical density of the MIT. Our new results suggest that the sharp increase in the previously-observed spin susceptibility is mainly due to the enhanced effective mass. Therefore, renormalization of the effective mass could play an important role in a dilute spinpolarized 2DEG. The data indicate that electron-electron interactions strongly modify the effective mass but only weakly affect the g-factor in a dilute 2DEG. Moreover, our results indicate that B c , which corresponds to the magnetic field at which the magnetoresistivity reaches saturation, vanishes at a characteristic density n χ higher than the critical density n c of the MIT. This is in contrast to the existing experimental results, and further studies are required if this discrepancy is to be understood.

  20. Lifetime Measurements of Tagged Exotic- and Unbound Nuclear States

    SciTech Connect

    Cullen, D. M.

    2011-11-30

    A new Differential Plunger device for measuring pico-second lifetimes of Unbound Nuclear States (DPUNS) is being built at The University of Manchester. DPUNS has been designed to work with alpha-, beta- and isomer-tagging methods using the existing JUROGAM II--RITU--GREAT infrastructure at the University of Jyvaskyla, Finland. The importance of proton emission from nuclei is that it provides valuable nuclear-structure information as direct input to nuclear models beyond the drip line. New experimental data beyond the drip line can provide new extensions to these models especially with the possible coupling of weakly bound and unbound states to the continuum. The results of the first experiments to measure lifetimes of unbound nuclear states with this method was discussed along with possible future experiments which can be addressed with DPUNS using proton-, isomer- and alpha-tagging.

  1. Determination of parameters of a nuclear reactor through noise measurements

    DOEpatents

    Cohn, C.E.

    1975-07-15

    A method of measuring parameters of a nuclear reactor by noise measurements is described. Noise signals are developed by the detectors placed in the reactor core. The polarity coincidence between the noise signals is used to develop quantities from which various parameters of the reactor can be calculated. (auth)

  2. A dc amplifier for nuclear particle measurement

    NASA Technical Reports Server (NTRS)

    Macnee, A. B.; Masnari, N. A.

    1978-01-01

    A monolithic preamplifier-postamplifier combination has been developed for use with solid state particle detectors. The direct coupled amplifiers employ interdigitated n-channel JFET's, diodes, and diffused resistors. The circuits developed demonstrate the feasibility of matching the performance of existing discrete component designs. The fabrication procedures for the monolithic amplifier fabrication are presented and the results of measurements on a limited number of sample amplifiers are given.

  3. Measurements of nuclear spin dynamics by spin-noise spectroscopy

    SciTech Connect

    Ryzhov, I. I.; Poltavtsev, S. V.; Kozlov, G. G.; Zapasskii, V. S.; Kavokin, K. V.; Glazov, M. M.; Vladimirova, M.; Scalbert, D.; Cronenberger, S.; Lemaître, A.; Bloch, J.

    2015-06-15

    We exploit the potential of the spin noise spectroscopy (SNS) for studies of nuclear spin dynamics in n-GaAs. The SNS experiments were performed on bulk n-type GaAs layers embedded into a high-finesse microcavity at negative detuning. In our experiments, nuclear spin polarisation initially prepared by optical pumping is monitored in real time via a shift of the peak position in the electron spin noise spectrum. We demonstrate that this shift is a direct measure of the Overhauser field acting on the electron spin. The dynamics of nuclear spin is shown to be strongly dependent on the electron concentration.

  4. First Principles Computation of G-Factors in Bi and Bi2Se3

    NASA Astrophysics Data System (ADS)

    Song, Zhida; Nie, Simin; di, Xi; Fang, Zhong; T03 Team

    In this talk, we propose a first principles computation method for g-factor tensor,which not only gives comparable results with experiments but also establishes a clear physical picture of Zeeman effect in materials. In our method, the Hilbert space of the electronic states is treated as a direct product of ''inner'' space and ''orbital'' space, which are spanned by Bloch wave-functions and envelope functions respectively. Correspondingly, vector-potential is divided into a periodic part acting only in inner space and a non-periodic part acting only in orbital space. With the above flamework we define the g-factors as coupling coefficients between inner space and magnetic field. By the method we developed, we have further computed the g-factors of bismuth and Bi2Se3 and get satisfactory results, which are in good agreement with the experimental data.

  5. Temperature and donor concentration dependence of the conduction electron Lande g-factor in silicon

    NASA Astrophysics Data System (ADS)

    Konakov, Anton A.; Ezhevskii, Alexander A.; Soukhorukov, Andrey V.; Guseinov, Davud V.; Popkov, Sergey A.; Burdov, Vladimir A.

    2013-12-01

    Temperature and donor concentration dependence of the conduction electron g-factor in silicon has been investigated both experimentally and theoretically. We performed electron spin resonance experiments on Si samples doped with different densities of phosphorus and lithium. Theoretical consideration is based on the renormalization of the electron energy in a weak magnetic field by the interaction with possible perturbing agents, such as phonons and impurity centers. In the second-order perturbation theory interaction of the electron subsystem with the lattice vibrations as well as ionized donors results in decreasing the conduction electron g-factor, which becomes almost linear function both of temperature and impurity concentration.

  6. Temperature dependence of the electron Landé g-factor in cubic GaN

    NASA Astrophysics Data System (ADS)

    Buß, J. H.; Schupp, T.; As, D. J.; Hägele, D.; Rudolph, J.

    2015-12-01

    The temperature dependence of the electron Landé g-factor in bulk cubic GaN is investigated over an extremely broad temperature range from 15 K up to 500 K by time-resolved Kerr-rotation spectroscopy. The g-factor is found to be approximately constant over the full investigated temperature range. Calculations by k .p -theory predict a negligible temperature dependence g(T) in complete agreement with the experiment as a consequence of the large band-gap and small spin orbit splitting in cubic GaN.

  7. Recent measurements for hadrontherapy and space radiation: nuclear physics

    NASA Technical Reports Server (NTRS)

    Miller, J.

    2001-01-01

    The particles and energies commonly used for hadron therapy overlap the low end of the charge and energy range of greatest interest for space radiation applications, Z=1-26 and approximately 100-1000 MeV/nucleon. It has been known for some time that the nuclear interactions of the incident ions must be taken into account both in treatment planning and in understanding and addressing the effects of galactic cosmic ray ions on humans in space. Until relatively recently, most of the studies of nuclear fragmentation and transport in matter were driven by the interests of the nuclear physics and later, the hadron therapy communities. However, the experimental and theoretical methods and the accelerator facilities developed for use in heavy ion nuclear physics are directly applicable to radiotherapy and space radiation studies. I will briefly review relevant data taken recently at various accelerators, and discuss the implications of the measurements for radiotherapy, radiobiology and space radiation research.

  8. 78 FR 45573 - Compensatory and Alternative Regulatory Measures for Nuclear Power Plant Fire Protection (CARMEN...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-29

    ... COMMISSION Compensatory and Alternative Regulatory Measures for Nuclear Power Plant Fire Protection (CARMEN-FIRE) AGENCY: Nuclear Regulatory Commission. ACTION: Notice of availability; request for public comment.../CR-7135, ``Compensatory and Alternative Regulatory Measures for Nuclear Power Plant Fire...

  9. Nuclear resonance scattering measurement of human iron stores

    SciTech Connect

    Wielopolski, L.; Ancona, R.C.; Mossey, R.T.; Vaswani, A.N.; Cohn, S.H.

    1985-07-01

    Hepatic iron stores were measured noninvasively in 31 patients (thalassemia, hemodialysis, hemosiderosis, refractory anemia) with suspected iron overload, employing a nuclear resonance scattering (NRS) technique. The thalassemia patients were undergoing desferrioxamine chelation therapy during the NRS measurements. The hemodialysis patients were measured before chelation therapy. Iron levels measured by NRS were in general agreement with those determined in liver biopsies by atomic absorption spectroscopy. In addition, NRS measurements from the thorax of some of these patients suggest that this method may also prove useful for clinical assessment of cardiac iron.

  10. Electrically tunable hole g factor of an optically active quantum dot for fast spin rotations

    NASA Astrophysics Data System (ADS)

    Prechtel, Jonathan H.; Maier, Franziska; Houel, Julien; Kuhlmann, Andreas V.; Ludwig, Arne; Wieck, Andreas D.; Loss, Daniel; Warburton, Richard J.

    2015-04-01

    We report a large g factor tunability of a single hole spin in an InGaAs quantum dot via an electric field. The magnetic field lies in the in-plane direction x , the direction required for a coherent hole spin. The electrical field lies along the growth direction z and is changed over a large range, 100 kV/cm. Both electron and hole g factors are determined by high resolution laser spectroscopy with resonance fluorescence detection. This, along with the low electrical-noise environment, gives very high quality experimental results. The hole g factor ghx depends linearly on the electric field Fz,d ghx/d Fz=(8.3 ±1.2 ) ×10-4 cm/kV, whereas the electron g factor gex is independent of electric field d gex/d Fz=(0.1 ±0.3 ) ×10-4 cm/kV (results averaged over a number of quantum dots). The dependence of ghx on Fz is well reproduced by a 4 ×4 k .p model demonstrating that the electric field sensitivity arises from a combination of soft hole confining potential, an In concentration gradient, and a strong dependence of material parameters on In concentration. The electric field sensitivity of the hole spin can be exploited for electrically driven hole spin rotations via the g tensor modulation technique and based on these results, a hole spin coupling as large as ˜1 GHz can be envisaged.

  11. Using Nuclear Magnetic Resonance Spectroscopy for Measuring Ternary Phase Diagrams

    ERIC Educational Resources Information Center

    Woodworth, Jennifer K.; Terrance, Jacob C.; Hoffmann, Markus M.

    2006-01-01

    A laboratory experiment is presented for the upper-level undergraduate physical chemistry curriculum in which the ternary phase diagram of water, 1-propanol and n-heptane is measured using proton nuclear magnetic resonance (NMR) spectroscopy. The experiment builds upon basic concepts of NMR spectral analysis, typically taught in the undergraduate…

  12. Electron impact cross section measurements related to 'nuclear pumping'

    NASA Technical Reports Server (NTRS)

    Trajmar, S.

    1979-01-01

    In direct nuclear pumped lasers the high energy fission fragments generate a large number of secondary electrons and these electrons are mainly responsible for achieving the population inversion in the lasing media. Laboratory measurements concerned with these electron impact processes are summarized and new results are presented on rare gases, N2, CO, CF3I and UF6.

  13. Measurement of nuclear dependence of pT at Fermilab

    NASA Astrophysics Data System (ADS)

    Wang, Suyin; E906/SeaQuest Collaboration

    2015-10-01

    The suppression of JPsi and Psi' production in the heavy ion collisions relative to their production in the p+p collisions has been proposed as one of the important signatures of the quark-gluon plasma (QGP) formation. The nuclear dependence of JPsi and Psi' production in the p+A collisions is essential to characterize the important baseline of the cold nuclear matter effect in both the initial and final states of collisions. In addition the final-state effect can be further differentiated in comparison with the nuclear dependence of Drell-Yan process. Fermilab E906/SeaQuest is a fixed-target experiment where the JPsi, Psi' and Drell-Yan productions from 120-GeV proton beam colliding with protons and various nuclear targets are measured simultaneously via the dimuon channel. In this talk we will report the recent progress of nuclear dependence of these productions as a function of the transverse momentum of dimuon from E906/SeaQuest's measurements. The results will be compared to those of E866 experiment obtained at higher beam energies. SuYin Wang is with Institute of Physics, Academia Sinica, Taiwan, and Particle Physics Division, Fermi National Accelerator Laboratory, USA. She is also a Ph.D. student from Department of Physics, National Kaohsiung Normal University, Taiwan.

  14. Nuclear fragmentation measurements for hadrontherapy and space radiation protection

    SciTech Connect

    De Napoli, M.; Agodi, C.; Blancato, A. A.; Cavallaro, M.; Cirrone, G. A. P.; Cuttone, G.; Sardina, D.; Scuderi, V.; Battistoni, G.; Bondi, M.; Cappuzzello, F.; Carbone, D.; Nicolosi, D.; Raciti, G.; Tropea, S.; Giacoppo, F.; Morone, M. C.; Pandola, L.; Rapisarda, E.; Romano, F.; and others

    2013-04-19

    Nuclear fragmentation measurements are necessary in hadrontherapy and space radiation protection, to predict the effects of the ion nuclear interactions within the human body. Nowadays, a very limited set of carbon fragmentation cross sections has been measured and in particular, to our knowledge, no double differential fragmentation cross sections at intermediate energies are available in literature. We have measured the double differential cross sections and the angular distributions of the secondary fragments produced in the {sup 12}C fragmentation at 62 AMeV on a thin carbon target. The experimental data have been also used to benchmark the prediction capability of the Geant4 Monte Carlo code at intermediate energies, where it was never tested before.

  15. Relativistic CI+all-order calculations of U III energies, g-factors, transition rates and lifetimes

    NASA Astrophysics Data System (ADS)

    Savukov, Igor; Safronova, Ulyana; Safronova, Marianna

    2016-05-01

    Excitation energies, term designations, g-factors, transition rates and lifetimes of U2+ are determined using a relativistic configuration interaction (CI) + all-order (linearized coupled-cluster, LCC) approach. The all-order energies are compared with CI+many-body-perturbation-theory (MBPT) and available experimental energies. Close agreement has been found with experiment, within hundreds of cm-1. In addition, lifetimes of higher levels have been calculated for comparison with three experimentally measured lifetimes, and close agreement was found within t he experimental error. CI-LCC calculations constitute a benchmark test of the CI+all-order method in complex relativistic systems such as actinides and their ions with many valence electrons. The theory yields many energy levels, g-factors, transition rates, and lifetimes of U2+ that are not available from experiment. The theory can be applied to other multi-valence atoms and ions, which would be of interest to many applications. The work of I. Savukov has been performed under the auspices of the U.S. DOE by LANL under Contract No. DE-AC52-06NA25396.M.S.S. acknowledges support from the Gordon Godfrey Fellowship program, UNSW and U.S. NSF Grant No. PHY-1404156.

  16. Nuclear Data Measurements for 21st Century Reactor Physics Applications

    SciTech Connect

    Rahmat Aryaeinejad; Jerald D. Cole; Mark W. Drigert; James K. Jewell; Christopher A. McGrath; David W. Nigg; Edward L. Reber

    2003-03-01

    The United States Department of Energy (DOE), Office of Nuclear Energy (NE) has embarked on a long-term program to significantly advance the science and technology of nuclear energy. This is in response to the overall national plan for accelerated development of domestic energy resources on several fronts, punctuated by recent dramatic events that have emphasized the need for the US to reduce its dependence on foreign petroleum supplies. Key aspects of the DOE-NE agenda are embodied in the Generation-IV (Gen-IV) advanced nuclear energy systems development program and in the Advanced Fuel Cycle (AFC) program. The planned efforts involve near-term and intermediate-term improvements in fuel utilization and recycling in current nuclear power reactor systems as well as the longer-term development of new nuclear energy systems that offer much improved fuel utilization and proliferation resistance, along with continued advances in operational safety. The success of the overall NE effort will depend not only on sophisticated system development and engineering, but also on the advances in the supporting sciences and technologies. Of these, one of the most important is the improvement of the relevant fundamental nuclear science data bases, especially the evaluated neutron interaction cross section files that serve as the foundation of all reactor system designs, operating strategies, and fuel cycle engineering activities. The new concepts for reactors and fuel cycles involve the use of transuranic nuclides that were previously of little interest, and where experimentally measured information is lacking. The current state of the cross section database for some of these nuclides is such that design computations for advanced fast-spectrum reactor systems and fuel cycles that incorporate such materials in significant quantities are meaningful only for approximate conceptual applications. No actual system could reliably be designed according to currently accepted standards, nor

  17. Light nuclear charge measurement with Alpha Magnetic Spectrometer Electromagnetic Calorimeter

    NASA Astrophysics Data System (ADS)

    Basara, Laurent; Choutko, Vitaly; Li, Qiang

    2016-06-01

    The Alpha Magnetic Spectrometer (AMS) is a high energy particle detector installed and operating on board of the International Space Station (ISS) since May 2011. So far more than 70 billion cosmic ray events have been recorded by AMS. In the present paper the Electromagnetic Calorimeter (ECAL) detector of AMS is used to measure cosmic ray nuclear charge magnitudes up to Z=10. The obtained charge magnitude resolution is about 0.1 and 0.3 charge unit for Helium and Carbon, respectively. These measurements are important for an accurate determination of the interaction probabilities of various nuclei with the AMS materials. The ECAL charge calibration and measurement procedures are presented.

  18. Thermal measurements in the nuclear winter fire test

    SciTech Connect

    Schneider, M.E.; Keltner, N.R.; Kent, L.A.

    1989-01-01

    In March, 1987, a large open pool fire test was performed to provide test measurements to help define the thermal characteristics of large open pool fires and estimates of the smoke source term for the nuclear winter (global effects) scenario. This report will present the results of the thermal measurements as well as comparisons with previous test results. These measurements included flame temperatures, heat fluxes to a variety of calorimeters, and gas velocities in the lower flame regions. 13 refs., 76 figs., 7 tabs.

  19. Effective g-factors of carriers in inverted InAs/GaSb bilayers

    NASA Astrophysics Data System (ADS)

    Mu, Xiaoyang; Sullivan, Gerard; Du, Rui-Rui

    2016-01-01

    We perform tilt-field transport experiment on inverted InAs/GaSb, which hosts quantum spin Hall insulator. By means of coincidence method, Landau level (LL) spectra of electron and hole carriers are systematically studied at different carrier densities tuned by gate voltages. When Fermi level stays in the conduction band, we observe LL crossing and anti-crossing behaviors at odd and even filling factors, respectively, with a corresponding g-factor of 11.5. It remains nearly constant for varying filling factors and electron densities. On the contrary, for GaSb holes, only a small Zeeman splitting is observed even at large tilt angles, indicating a g-factor of less than 3.

  20. Further investigation of g factors for the lead monofluoride ground state

    DOE PAGESBeta

    Skripnikov, L. V.; Petrov, A. N.; Titov, A. V.; Mawhorter, R. J.; Baum, A. L.; Sears, T. J.; Grabow, J. -U.

    2015-09-15

    We report the results of our theoretical study and analysis of earlier experimental data for the g-factor tensor components of the ground 2II1/2 state of the free PbF radical. These values obtained both within the relativistic coupled-cluster method combined with the generalized relativistic effective core potential approach and with our fit of the experimental data from [R. J. Mawhorter, B. S. Murphy, A. L. Baum, T. J. Sears, T. Yang, P. M. Rupasinghe, C. P. McRaven, N. E. Shafer-Ray, L. D. Alphei, and J.-U. Grabow, Phys. Rev. A 84, 022508 (2011); A. L. Baum, B.A. thesis, Pomona College, 2011]. Themore » obtained results agree very well with each other but contradict the previous fit performed in the cited works. Our final prediction for g factors is G∥=0.081(5),G⊥=–0.27(1).« less

  1. Tuning g factors of core-shell nanoparticles by controlled positioning of magnetic impurities

    NASA Astrophysics Data System (ADS)

    Sanders, G. D.; Musfeldt, J. L.; Stanton, C. J.

    2016-02-01

    We present a theoretical platform for modeling the electronic and magneto-optic properties of magnetically doped core-shell nanoparticles that has, as a central prediction, a mechanism by which the g factors in these nanoparticles can be tuned over a wide range by controlled positioning of magnetic impurities. We illustrate this effect for wide-gap Mn-doped CdS-ZnS core-shell particles and point out several unexpected trends that merit extended experimental investigation. The ability to tune g factors will make core-shell nanostructures viable candidates for spintronic applications, and the comprehensive modeling approach outlined here will be a powerful tool for predicting their properties as well as for optimizing the design of novel spintronic devices.

  2. Further investigation of g factors for the lead monofluoride ground state

    NASA Astrophysics Data System (ADS)

    Skripnikov, L. V.; Petrov, A. N.; Titov, A. V.; Mawhorter, R. J.; Baum, A. L.; Sears, T. J.; Grabow, J.-U.

    2015-09-01

    We report the results of our theoretical study and analysis of earlier experimental data for the g -factor tensor components of the ground 2Π1 /2 state of the free PbF radical. The values were obtained both within the relativistic coupled-cluster method combined with the generalized relativistic effective core potential approach and with our fit of the experimental data from [R. J. Mawhorter, B. S. Murphy, A. L. Baum, T. J. Sears, T. Yang, P. M. Rupasinghe, C. P. McRaven, N. E. Shafer-Ray, L. D. Alphei, and J.-U. Grabow, Phys. Rev. A 84, 022508 (2011), 10.1103/PhysRevA.84.022508; A. L. Baum, B.A. thesis, Pomona College, 2011]. The obtained results agree very well with each other but contradict the previous fit performed in the cited works. Our final prediction for g factors is G∥=0.081 (5 ) ,G⊥=-0.27 (1 ) .

  3. Temperature dependence of the electron spin g factor in CdTe and InP

    NASA Astrophysics Data System (ADS)

    Pfeffer, Pawel; Zawadzki, Wlodek

    2012-04-01

    Temperature dependence of the electron spin g factors in bulk CdTe and InP is calculated and compared with experiment. It is assumed that the only modification of the band structure related to temperature is a dilatation change in the fundamental energy gap. The dilatation changes of fundamental gaps are calculated for both materials using available experimental data. Computations of the band structures in the presence of a magnetic field are carried out employing five-level P.p model appropriate for medium-gap semiconductors. In particular, the model takes into account spin splitting due to bulk inversion asymmetry (BIA) of the materials. The resulting theoretical effective masses and g factors increase with electron energy due to band nonparabolicity. Average g values are calculated by summing over populated Landau and spin levels properly accounting for the thermal distribution of electrons in the band. It is shown that the spin splitting due to BIA in the presence of a magnetic field gives observable contributions to g values. Our calculations are in good agreement with experiments in the temperature range of 0 K to 300 K for CdTe and 0 K to 180 K for InP. The temperature dependence of g is stronger in CdTe than in InP due to different signs of band-edge g values in the two materials. Good agreement between the theory and experiments strongly indicates that the temperature dependence of spin g factors is correctly explained. In addition, we discuss formulas for the energy dependence of spin g factor due to band nonparabolicity, which are liable to misinterpretation.

  4. Precision Penning Trap Mass Measurements for Nuclear Structure at Triumf

    NASA Astrophysics Data System (ADS)

    Kwiatkowski, A. A.; Dilling, J.; Andreoiu, C.; Brunner, T.; Chaudhuri, A.; Chowdhury, U.; Delheij, P.; Ettenauer, S.; Frekers, D.; Gallant, A. T.; Grossheim, A.; Gwinner, G.; Lennarz, A.; Mané, E.; Pearson, M. R.; Schultz, B. E.; Simon, M. C.; Simon, V. V.

    2013-03-01

    Precision determinations of ground state or even isomeric state masses reveal fingerprints of nuclear structure. In particular at the limits at existence for very neutron-rich or deficient isotopes, this allows one to find detailed information about nuclear structure from separation energies or binding energies. This is important to test theoretical predictions or to refine model approaches, for example for new "magic numbers," as predicted around N = 34, where strong indications exist that the inclusion of NNN forces in theoretical calculations for Ca isotopes leads to significantly better predictions for ground state binding energies. Similarly, halo nuclei present an excellent application for ab-initio theory, where ground state properties, like masses and radii, present prime parameters for testing our understanding of nuclear structure. Precision mass determinations at TRIUMF are carried out with the TITAN (TRIUMF's Ion Trap for Atomic and Nuclear science) system. It is an ion trap setup coupled to the on-line facility ISAC. TITAN has measured masses of isotopes as short-lived as 9 ms (almost an order of magnitude shorter-lived than any other Penning trap system) and the only one with charge breeding capabilities, a feature that allows us to boost the precision by almost 2 orders of magnitude. We recently were able to make use of this feature by measuring short-lived Rb-isotopes, up to 74Rb, and reaching the 12+ charge state, which together with other improvements lead to an increase in precision by a factor 36.

  5. Exchange enhancement of the electron g factor in strained InGaAs/InP heterostructures

    SciTech Connect

    Krishtopenko, S. S.; Maremyanin, K. V. Kalinin, K. P.; Spirin, K. E.; Gavrilenko, V. I.; Baidus, N. V.; Zvonkov, B. N.

    2015-02-15

    The exchange enhancement of the electron g factor in strained InGaAs/InP heterostructures with a two-dimensional electron gas is studied. Analysis of the temperature dependence of the resistance in the minima of the Shubnikov-de Haas oscillations in perpendicular magnetic fields up to 12 T in the vicinity of the odd filling factors of the Landau levels yields the values of the effective electron Lande factor g* from −8.6 to −10.1. The experimental values are compared with the results of theoretical calculations of the g factor of quasiparticles. The calculations are performed using an eight-band k · p Hamiltonian and take into account exchange interaction in the two-dimensional electron gas. It is shown that, under the conditions of a large overlap between the spin-split Landau levels, the maximum value of the quasiparticle g factor can be attained in the vicinity of even filling factors. This is caused by the nonparabolicity of the electron dispersion relation.

  6. Electron and hole g factors in InAs/InAlGaAs self-assembled quantum dots emitting at telecom wavelengths

    NASA Astrophysics Data System (ADS)

    Belykh, V. V.; Greilich, A.; Yakovlev, D. R.; Yacob, M.; Reithmaier, J. P.; Benyoucef, M.; Bayer, M.

    2015-10-01

    We extend the range of quantum dot (QD) emission energies where electron and hole g factors have been measured to the practically important telecom range. The spin dynamics in InAs/In0.53Al0.24Ga0.23As self-assembled QDs with emission wavelengths at about 1.6 μ m grown on InP substrate is investigated by pump-probe Faraday rotation spectroscopy in a magnetic field. Pronounced oscillations on two different frequencies, corresponding to the QD electron and hole spin precessions about the field, are observed from which the corresponding g factors are determined. The electron g factor of about -1.9 has the largest negative value so far measured for III-V QDs by optical methods. This value, as well as the g factors reported for other III-V QDs, differ from those expected for bulk semiconductors at the same emission energies, and this difference increases significantly for decreasing energies.

  7. Measurements of ϒ Production and Nuclear Modification Factor at STAR

    NASA Astrophysics Data System (ADS)

    Kesich, Anthony

    2013-08-01

    Thermal suppression of quarkonium production in heavy-ion collisions, due to Debye screening of the quark-antiquark potential, has been proposed as a clear signature of Quark-Gluon Plasma (QGP) formation. At RHIC energies, the ϒ meson is a clean probe of the early system due to negligible levels of enhancement from bbbar recombination and non-thermal suppression from co-mover absorption. We report on our measurement of the ϒ →e+e- cross section in Au+Au collisions at √{sNN} = 200 GeV. We compute the Nuclear Modification Factor by comparing these results to new p+p measurements from 2009 (21pb-1 in 2009 compared to 7.9pb-1 in 2006). In order to have a complete assessment of both hot and cold nuclear matter effects on Upsilon production we also report on results from d+Au collisions.

  8. A nuclear data approach for the Hubble constant measurements

    SciTech Connect

    Pritychenko, B.

    2015-06-09

    An extraordinary number of Hubble constant measurements challenges physicists with selection of the best numerical value. The standard U.S. Nuclear Data Program (USNDP) codes and procedures have been applied to resolve this issue. The nuclear data approach has produced the most probable or recommended Hubble constant value of 67.00(770) (km/sec)/Mpc. This recommended value is based on the last 25 years of experimental research and includes contributions from different types of measurements. The present result implies (14.6±1.7) x 109 years as a rough estimate for the age of the Universe. The complete list of recommended results is given and possible implications are discussed.

  9. Method and apparatus for measuring nuclear magnetic properties

    DOEpatents

    Weitekamp, Daniel P.; Bielecki, Anthony; Zax, David B.; Zilm, Kurt W.; Pines, Alexander

    1987-01-01

    A method for studying the chemical and structural characteristics of materials is disclosed. The method includes placement of a sample material in a high strength polarizing magnetic field to order the sample nucleii. The condition used to order the sample is then removed abruptly and the ordering of the sample allowed to evolve for a time interval. At the end of the time interval, the ordering of the sample is measured by conventional nuclear magnetic resonance techniques.

  10. Method and apparatus for measuring nuclear magnetic properties

    DOEpatents

    Weitekamp, D.P.; Bielecki, A.; Zax, D.B.; Zilm, K.W.; Pines, A.

    1987-12-01

    A method for studying the chemical and structural characteristics of materials is disclosed. The method includes placement of a sample material in a high strength polarizing magnetic field to order the sample nuclei. The condition used to order the sample is then removed abruptly and the ordering of the sample allowed to evolve for a time interval. At the end of the time interval, the ordering of the sample is measured by conventional nuclear magnetic resonance techniques. 5 figs.

  11. Measurement and Characterization of Nuclear Material at Idaho National Laboratory

    SciTech Connect

    J. L. Dolan; M. Flaska; S. A. Pozzi; D. L. Chichester

    2009-07-01

    A measurement plan and preliminary Monte Carlo simulations are presented for the investigation of well-defined mixed-oxide fuel pins. Measurement analysis including pulse-height distributions and time-dependent cross-correlation functions will be performed separately for neutrons and gamma rays. The utilization of Monte Carlo particle transport codes, specifically MCNP-PoliMi, is discussed in conjunction with the anticipated measurements. Four EJ-309 liquid scintillation detectors with an accurate pulse timing and digital, offline, optimized pulse-shape discrimination method will be used to prove the dependency of pulse-height distributions, cross-correlation functions, and material multiplicities upon fuel pin composition, fuel pin quantity, and detector geometry. The objective of the measurements and simulations is to identify novel methods for describing mixed-oxide fuel samples by relating measured quantities to fuel characteristics such as criticality, mass quantity, and material composition. This research has applications in nuclear safeguards and nonproliferation.

  12. Indirect measurement of nuclear reactions of astrophysical interest

    SciTech Connect

    Liu, W. P.; Li, Z. H.; Bai, X. X.; Wang, Y. B.; Guo, B.; Lian, G.; Su, J.; Zeng, S.; Wang, B. X.; Yan, S. Q.; Li, Y. J.; Li, E. T.; Jin, S. J.

    2010-05-12

    Systematic indirect measurements of nuclear astrophysical reactions using the unstable ion beam facility GIRAFFE in CIAE were performed. We have measured the angular distributions of transfer reactions, such as {sup 8}Li(d,p){sup 9}Li, {sup 8}Li(d,n){sup 9}Be and {sup 8}Li(p,d){sup 7}Li in inverse kinematics, and derived the astrophysical S-factors or reaction rates for {sup 8}Li(n,gamma){sup 9}Li and {sup 8}Li(p,gamma){sup 9}Be by using asymptotic normalization coefficient (ANC) or spectroscopic factor methods.

  13. Experiments with Exotic Spin-Oriented Nuclear Beams and Examples of Nuclear Moment Measurements

    NASA Astrophysics Data System (ADS)

    Balabanski, D. L.; Neyens, G.; Borremans, D.; Coulier, N.; Daugas, J. M.; Teughels, S.; Georgiev, G.; Lewitowicz, M.; de Oliveira Santos, F.; Penionzhkevich, Yu. E.

    2002-04-01

    An overview of a series of recent experiments aimed at the determination of the moments of exotic nuclei is presented. The spin-orientation: spin-alignment and spin-polarization of the nuclear ensemble, which is produced in fragmentation reactions, is of utmost importance for these studies. The discussion emphasizes on the open problems related to the production and the preservation of the orientation during the experiments. Pros and contras for experiments at both, intermediate and high energies are considered. Examples from nuclear moment measurements, which were performed using the LISE-III spectrometer at GANIL, are provided. The spin-alignment and the spin-polarization of the nuclear ensemble were studied by the β-LMR, β-NMR and TDPAD experimental techniques. The experimental results are discussed in the framework of the kinematical model of the fragmentation reaction.

  14. Senate examines measures to improve nuclear safety following Japan disaster

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2012-03-01

    One year after Japan suffered a devastating magnitude 9.0 earthquake and the resulting tsunami and nuclear disaster, the U.S. Nuclear Regulatory Commission (NRC) has taken a number of measures to try to ensure that nuclear plants in the United States are safe from natural hazards. At a U.S. Senate hearing on 15 March, NRC chair Gregory Jaczko announced that the commission had issued three key orders and several requests for information on 12 March that plant licensees must follow, and that NRC also plans to take additional actions. However, the commission is not moving quickly enough in some areas, such as ensuring that all plants are safe from seismic hazards, including those in areas with low seismic activity, according to Jaczko's testimony before the Senate Committee on Environment and Public Works (EPW) and the Subcommittee on Clean Air and Nuclear Safety. The 12 March orders require licensees to have strategies to maintain or restore core cooling, containment, and spent-fuel pool cooling capabilities "following a beyond-design-basis extreme natural event" and have a reliable indication of the water level in spent-fuel storage pools.

  15. Charged fusion product loss measurements using nuclear activation.

    PubMed

    Bonheure, G; Hult, M; González de Orduña, R; Arnold, D; Dombrowski, H; Laubenstein, M; Wieslander, E; Vermaercke, P; Murari, A; Popovichev, S; Mlynar, J

    2010-10-01

    In ITER, α particle loss measurements will be required in order to understand the alpha particle physics. Techniques capable of operating in a fusion reactor environment need further development. Recent experimental studies on JET demonstrated the potential of nuclear activation to measure the flux of escaping MeV ions. New results from MeV ion induced activation of metallic, ceramic, and crystal samples placed near the plasma edge are reported. Activation products were measured as function of orientation with respect to the magnetic field as well as function of the distance to the plasma. Sample activity was measured using ultralow-level gamma-ray spectrometry. Distribution of 14.68 MeV fusion proton induced activation products is strongly anisotropic in agreement with simulations and falls off sharply with increasing distance to the plasma. Prospects for using the technique in ITER are discussed. PMID:21058458

  16. Gamma Ray Mirrors for Direct Measurement of Spent Nuclear Fuel

    SciTech Connect

    Pivovaroff, Dr. Michael J.; Ziock, Klaus-Peter; Harrison, Mark J; Soufli, Regina

    2014-01-01

    Direct measurement of the amount of Pu and U in spent nuclear fuel represents a challenge for the safeguards community. Ideally, the characteristic gamma-ray emission lines from different isotopes provide an observable suitable for this task. However, these lines are generally lost in the fierce flux of radiation emitted by the fuel. The rates are so high that detector dead times limit measurements to only very small solid angles of the fuel. Only through the use of carefully designed view ports and long dwell times are such measurements possible. Recent advances in multilayer grazing-incidence gamma-ray optics provide one possible means of overcoming this difficulty. With a proper optical and coating design, such optics can serve as a notch filter, passing only narrow regions of the overall spectrum to a fully shielded detector that does not view the spent fuel directly. We report on the design of a mirror system and a number of experimental measurements.

  17. Nuclear data measurements at the new NFS facility at GANIL

    NASA Astrophysics Data System (ADS)

    Gustavsson, C.; Pomp, S.; Scian, G.; Lecolley, F.-R.; Tippawan, U.; Watanabe, Y.

    2012-10-01

    The NFS (Neutrons For Science) facility is part of the SPRIAL 2 project at GANIL, Caen, France. The facility is currently under construction and the first beam is expected in early 2013. NFS will have a white neutron source covering the 1-40 MeV energy range with a neutron flux higher than comparable facilities. A quasi-mono-energetic neutron beam will also be available. In these energy ranges, especially above 14 MeV, there is a large demand for neutron-induced data for a wide range of applications involving dosimetry, medical therapy, single-event upsets in electronics and nuclear energy. Today, there are a few or no cross section data on reactions such as (n, fission), (n, xn), (n, p), (n, d) and (n, α). We propose to install experimental equipment for measuring neutron-induced light-charged particle production and fission relative to the H(n, p) cross section. Both the H(n, p) cross section and the fission cross section for 238U are important reference cross sections used as standards for many other experiments. Nuclear data for certain key elements, such as closed shell nuclei, are also of relevance for the development of nuclear reaction models. Our primary intention is to measure charged particle production (protons, deuterons and alphas) from 12C, 16O, 28Si and 56Fe and neutron-induced fission cross sections from 238U and 232Th.

  18. Zeeman splitting and g factor of the 1s{sup 2}2s{sup 2}2p {sup 2}P{sub 3/2} and {sup 2}P{sub 1/2} levels in Ar{sup 13+}

    SciTech Connect

    Soria Orts, R.; Crespo Lopez-Urrutia, J. R.; Bruhns, H.; Gonzalez Martinez, A. J.; Harman, Z.; Jentschura, U. D.; Keitel, C. H.; Lapierre, A.; Tawara, H.; Ullrich, J.; Tupitsyn, I. I.; Volotka, A. V.

    2007-11-15

    The Zeeman line components of the magnetic-dipole (M1) 1s{sup 2}2s{sup 2}2p {sup 2}P{sub 1/2}-{sup 2}P{sub 3/2} transition in boronlike Ar{sup 13+} were experimentally resolved by high-precision emission spectroscopy using the Heidelberg electron beam ion trap. We determined the gyromagnetic (g) factors of the ground and first-excited levels to be g{sub 1/2}=0.663(7) and g{sub 3/2}=1.333(2), respectively. This corresponds to a measurement of the g factor of a relativistic electron in a bound non-S state of a multielectron ion with a 1.5 parts-per-thousand accuracy. The results are compared to theoretical calculations by means of the configuration interaction Dirac-Fock-Sturmian method including electron correlation effects and additional quantum electrodynamic corrections. Our measurements show that the classical Lande g factor formula is sufficiently accurate to the present level of accuracy in few-electron ions of medium nuclear charge number Z.

  19. Temperature measuring analysis of the nuclear reactor fuel assembly

    SciTech Connect

    Urban, F. E-mail: zdenko.zavodny@stuba.sk; Kučák, L. E-mail: zdenko.zavodny@stuba.sk; Bereznai, J. E-mail: zdenko.zavodny@stuba.sk; Závodný, Z. E-mail: zdenko.zavodny@stuba.sk; Muškát, P. E-mail: zdenko.zavodny@stuba.sk

    2014-08-06

    Study was based on rapid changes of measured temperature values from the thermocouple in the VVER 440 nuclear reactor fuel assembly. Task was to determine origin of fluctuations of the temperature values by experiments on physical model of the fuel assembly. During an experiment, heated water was circulating in the system and cold water inlet through central tube to record sensitivity of the temperature sensor. Two positions of the sensor was used. First, just above the central tube in the physical model fuel assembly axis and second at the position of the thermocouple in the VVER 440 nuclear reactor fuel assembly. Dependency of the temperature values on time are presented in the diagram form in the paper.

  20. Trojan Horse technique to measure nuclear astrophysics rearrangement reactions

    NASA Astrophysics Data System (ADS)

    Spitaleri, Claudio

    2013-03-01

    The knowledge of nucleosynthesis and of energy production in stars requires an increasingly precise measurement of nuclear fusion reactions at the Gamow energy. Because of the Coulomb barrier reaction cross sections in astrophysics cannot be accessed directly at ultra -low energies, unless very favorable conditions are met. Moreover, the energies characterizing nuclear processes in several astrophysical contexts are so low that the presence of atomic electrons must be taken into account. Theoretical extrapolations of available data are then needed to derive astrophysical S(E)-factors. To overcome these experimental difficulties the Trojan Horse Method (THM) has been introduced. The method provides a valid alternative path to measure unscreened low-energy cross sections of reactions between charged particles, and to retrieve information on the electron screening potential when ultra-low energy direct measurements are available. While the theory has been discussed in detail in some theoretical works, present in the scientific literature, also in relation to different types of excitation functions (e.g. non-resonant and resonant), work on detailed methodology used to extract the events to be considered for the bare nucleus cross section measurements is still on going. In this work we will present some critical points in the application of THM that deserve to be discussed in more detail.

  1. Measurement of heat transfer coefficients by nuclear magnetic resonance.

    PubMed

    Gultekin, David H; Gore, John C

    2008-11-01

    We demonstrate an experimental method for the measurement of heat transfer coefficient for a fluid system by magnetic resonance imaging. In this method, the temporal variation of thermally induced nuclear shielding is monitored and the average heat transfer coefficient is measured as a function of fluid velocity. We examine the cases of natural convection and forced convection at fluid velocity up to 0.8 m s(-1). These cases correspond to low dimensionless Biot (Bi) number where the heat transfer is limited by thermal convection. We demonstrate the NMR method for two simple geometries, a cylinder and a sphere, to experimentally determine the heat transfer coefficient (h) in two NMR imaging and spectroscopy systems through measuring three NMR parameters, the chemical shift, magnetization and spin self diffusion coefficient. PMID:18524523

  2. Anisotropy of in-plane hole g factor in CdTe/ZnTe quantum dots

    NASA Astrophysics Data System (ADS)

    Bogucki, A.; Smoleński, T.; Goryca, M.; Kazimierczuk, T.; Kobak, J.; Pacuski, W.; Wojnar, P.; Kossacki, P.

    2016-06-01

    Optical studies of a bright exciton provide only limited information about the hole anisotropy in a quantum dot. In this work we present a universal method to study heavy-hole anisotropy using a dark exciton in a moderate in-plane magnetic field. By analysis of the linear polarization of the dark exciton photoluminescence we identify two distinct contributions to the hole g factor: the anisotropic one resulting in a fixed orientation of the dark exciton polarization for any direction of the magnetic field and the quasi-isotropic contribution, due to which the polarization orientation rotates with the magnetic field, but in the opposite direction. We employ the proposed method for a number of individual self-assembled CdTe/ZnTe quantum dots, demonstrating a variety of behaviors of in-plane hole g factor: from almost fully anisotropic to almost quasi-isotropic. We conclude that, in general, both contributions play an important role and neither contribution can be neglected.

  3. Electric dipole spin resonance in systems with a valley-dependent g factor

    NASA Astrophysics Data System (ADS)

    Rančić, Marko J.; Burkard, Guido

    2016-05-01

    In this theoretical study we qualitatively and quantitatively investigate the electric dipole spin resonance (EDSR) in a single Si/SiGe quantum dot in the presence of a magnetic field gradient, e.g., produced by a ferromagnet. We model a situation in which the control of electron spin states is achieved by applying an oscillatory electric field, inducing real-space oscillations of the electron inside the quantum dot. One of the goals of our study is to present a microscopic theory of valley-dependent g factors in Si/SiGe quantum dots and investigate how valley relaxation combined with a valley-dependent g factor leads to a novel electron spin dephasing mechanism. Furthermore, we discuss the interplay of spin and valley relaxations in Si/SiGe quantum dots. Our findings suggest that the electron spin dephases due to valley relaxation, and are in agreement with recent experimental studies [Nat. Nanotechnol. 9, 666 (2014), 10.1038/nnano.2014.153].

  4. Measurement of nuclear-physical characteristics of radionuclides

    SciTech Connect

    Geidel'man, A.M.; Egorov, Yu.S.; Nedovesov, V.G.; Shchukin, G.E.

    1987-08-01

    This article provides the revised data for the nuclear-physical characteristics (NPC) measurements of seven radionuclides: /sup 238/Pu, /sup 239/Pu, /sup 55/Fe, /sup 125m/Te, /sup 119m/Sn, /sup 75/Se, and /sup 120/Tm. These radionuclides are widely used in the preparation of various radionuclide products, standard sources of ionizing radiation, and standard solutions. The emission characteristics data for the nuclides may be used for calibration of semiconductor spectrometers with regard to energy and efficiency.

  5. Superallowed nuclear beta decay: Precision measurements for basic physics

    SciTech Connect

    Hardy, J. C.

    2012-11-20

    For 60 years, superallowed 0{sup +}{yields}0{sup +} nuclear beta decay has been used to probe the weak interaction, currently verifying the conservation of the vector current (CVC) to high precision ({+-}0.01%) and anchoring the most demanding available test of the unitarity of the Cabibbo-Kobayashi-Maskawa (CKM) matrix ({+-}0.06%), a fundamental pillar of the electroweak standard model. Each superallowed transition is characterized by its ft-value, a result obtained from three measured quantities: the total decay energy of the transition, its branching ratio, and the half-life of the parent state. Today's data set is composed of some 150 independent measurements of 13 separate superallowed transitions covering a wide range of parent nuclei from {sup 10}C to {sup 74}Rb. Excellent consistency among the average results for all 13 transitions - a prediction of CVC - also confirms the validity of the small transition-dependent theoretical corrections that have been applied to account for isospin symmetry breaking. With CVC consistency established, the value of the vector coupling constant, G{sub V}, has been extracted from the data and used to determine the top left element of the CKM matrix, V{sub ud}. With this result the top-row unitarity test of the CKM matrix yields the value 0.99995(61), a result that sets a tight limit on possible new physics beyond the standard model. To have any impact on these fundamental weak-interaction tests, any measurement must be made with a precision of 0.1% or better - a substantial experimental challenge well beyond the requirements of most nuclear physics measurements. I overview the current state of the field and outline some of the requirements that need to be met by experimentalists if they aim to make measurements with this high level of precision.

  6. Indirect measurements of nuclear astrophysics reactions at CIAE

    SciTech Connect

    Liu Weiping; Li Zhihong; Bai Xixiang; Wang Youbao; Lian Gang; Guo Bing; Zeng Sheng; Yan Shengquan; Wang Baoxiang; Su Jun; Shu Nengchuan; Chen Yongshou

    2006-11-02

    This paper described the nuclear astrophysical studies using the unstable ion beam facility GIRAFFE, by indirect measurements. We measured the angular distributions for some single proton or neutron transfer reactions, such as 7Be(d,n)8B, 11C(d,n)12N, 8Li(d,n)9Be, 8Li(d,p)9Li and 13N(d,n)14O in inverse kinematics, and derived the astrophysical S-factors or reaction rates of 7Be(p,{gamma})8B, 11C(p,{gamma})12N, 8Li(n,{gamma})9Li, 13N(p,{gamma})14O by asymptotic normalization coefficient, spectroscopic factor, and R-matrix approach at astrophysically relevant energies.

  7. Proton Nuclear Magnetic Resonance Relaxation Measurements in Frog Muscle

    PubMed Central

    Finch, Edward D.; Homer, Louis D.

    1974-01-01

    Proton nuclear magnetic resonance (NMR) relaxation measurements are reported for frog muscle as a function of temperature and Larmor frequency. Each T1ρ, T2, and T1 measurement covered a time domain sufficient to identify the average relaxation time for most intracellular water. Using regression analysis the data were fit with a model where intracellular water molecules are exchanging between a large compartment in which mobility is similar to ordinary water and a small compartment in which motion is restricted. The regression results suggest that: the restricted compartment exhibits a distribution of motions skewed toward that of free water; the residence time of water molecules in the restricted compartment is approximately 1 ms; and, the activation entropy for some water molecules in the restricted compartment is negative. PMID:4547668

  8. Safeguards Measurement Evaluation Program nuclear materials measurement data: Phase 1: Final report, 1985 through 1986

    SciTech Connect

    Cacic, C.G.

    1988-08-01

    The New Brunswick Laboratory has been tasked by the US Department of Energy Office of Safeguards and Security to assess and evaluate the adequacy of measurement technology as applied to materials accounting in US Department of Energy nuclear facilities. The Safeguards Measurement Evaluation Program was developed as a means to monitor and evaluate the quality and effectiveness of accounting measurements by site, material balance area, or unit process. Phase 1 of the Safeguards Measurement Evaluation Program, initiated during 1985, involved evaluation of the primary accountability measurement methods at six US Department of Energy Defense Programs facilities. Resulting data are presented and evaluated as indicators of current state-of-the-practice accountability measurement methodology, deficiencies in materials accounting practices, and areas for possible assistance in upgrading measurement capabilities. 22 figs., 5 tabs.

  9. Holes localized in nanostructures in an external magnetic field: g-factor and mixing of states

    SciTech Connect

    Semina, M. A.; Suris, R. A.

    2015-06-15

    The energy spectrum and wave functions of holes in the valence band in semiconductor nanosystems, including quantum wells, quantum wires, and quantum dots, in an external magnetic field are theoretically investigated. The dependence of Zeeman splitting of the hole ground state upon variation in the size-quantization parameters with regard to the complex structure of the valence band and magnetic field-induced mixing of hole states is traced. Analytical formulas for describing the Zeeman effect in the valence band in the limiting cases of a quantum disk, spherically symmetric quantum dot, and quantum wire are presented. It is demonstrated that the g-factor of a hole is extremely sensitive to the hole-state composition (heavy or light hole) and, consequently, to the geometry of the size-quantization potential.

  10. Control of Majorana edge modes by a g-factor engineered nanowire spin transistor

    NASA Astrophysics Data System (ADS)

    De, Amrit; Kovalev, Alexey A.

    2014-11-01

    We propose the manipulation of Majorana edge states via hybridization and spin currents in a nanowire spin transistor. The spin transistor is based on a heterostructure nanowire comprising of semiconductors with large and small g-factors that form the topological and non-topological regions respectively. The hybridization of bound edge states results in spin currents and 4π-periodic torques, as a function of the relative magnetic field angle - an effect which is dual to the fractional Josephson effect. We establish relation between torques and spin-currents in the non-topological region where the magnetic field is almost zero and spin is conserved along the spin-orbit field direction. The angular momentum transfer could be detected by sensitive magnetic resonance force microscopy techniques.

  11. Electrical Control of g-Factor in a Few-Hole Silicon Nanowire MOSFET.

    PubMed

    Voisin, B; Maurand, R; Barraud, S; Vinet, M; Jehl, X; Sanquer, M; Renard, J; De Franceschi, S

    2016-01-13

    Hole spins in silicon represent a promising yet barely explored direction for solid-state quantum computation, possibly combining long spin coherence, resulting from a reduced hyperfine interaction, and fast electrically driven qubit manipulation. Here we show that a silicon-nanowire field-effect transistor based on state-of-the-art silicon-on-insulator technology can be operated as a few-hole quantum dot. A detailed magnetotransport study of the first accessible hole reveals a g-factor with unexpectedly strong anisotropy and gate dependence. We infer that these two characteristics could enable an electrically driven g-tensor-modulation spin resonance with Rabi frequencies exceeding several hundred mega-Hertz. PMID:26599868

  12. Nuclear Technology Series. Course 11: Radiation Detection and Measurement.

    ERIC Educational Resources Information Center

    Technical Education Research Center, Waco, TX.

    This technical specialty course is one of thirty-five courses designed for use by two-year postsecondary institutions in five nuclear technician curriculum areas: (1) radiation protection technician, (2) nuclear instrumentation and control technician, (3) nuclear materials processing technician, (4) nuclear quality-assurance/quality-control…

  13. Effective Mass and g-factor of 2D Electrons in a HgTe Quantum Well from THz Photoresponse

    NASA Astrophysics Data System (ADS)

    Pakmehr, Mehdi; Stier, A. V.; Zhang, H. D.; Bruene, C.; Buhmann, H.; Molenkamp, L.; McCombe, B. D.

    2013-03-01

    There is current interest in HgTe because of its interesting ``inverted'' band structure and large spin-orbit interaction, and because it is a topological insulator under quantum confinement, Well-widths close to that at which the band structure goes from the ``inverted'' to the normal structure are of particular interest. We have used photoresponse excited by several lines from an optically pumped THz laser and magnetotransport measurements to determine the cyclotron effective mass and g-factor of 2D electrons in the gamma_6 conduction band of a high quality HgTe quantum well (ns = 1.55 x 1012 cm-2; 6 nm well) at low temperatures. One of the two samples studied was gated, which allowed density to be varied by over 30%. We find m* =0.039me and g = -18 at the highest density from fits to the PR with the field normal to the plane of the QW, and separately from CR transmission measurements and tilted field experiments. We will also discuss electron spin resonance measurements near filling factors 7 and 9. Supported in part by NSF DMR 1008138

  14. Use of mathematical modeling in nuclear measurements projects

    SciTech Connect

    Toubon, H.; Menaa, N.; Mirolo, L.; Ducoux, X.; Khalil, R. A.

    2011-07-01

    Mathematical modeling of nuclear measurement systems is not a new concept. The response of the measurement system is described using a pre-defined mathematical model that depends on a set of parameters. These parameters are determined using a limited set of experimental measurement points e.g. efficiency curve, dose rates... etc. The model that agrees with the few experimental points is called an experimentally validated model. Once these models have been validated, we use mathematical interpolation to find the parameters of interest. Sometimes, when measurements are not practical or are impossible extrapolation is implemented but with care. CANBERRA has been extensively using mathematical modeling for the design and calibration of large and sophisticated systems to create and optimize designs that would be prohibitively expensive with only experimental tools. The case studies that will be presented here are primarily performed with MCNP, CANBERRA's MERCURAD/PASCALYS and ISOCS (In Situ Object Counting Software). For benchmarking purposes, both Monte Carlo and ray-tracing based codes are inter-compared to show models consistency and add a degree of reliability to modeling results. (authors)

  15. Depth Dependent Background Measurements with the Nuclear Compton Telescope (NCT)

    NASA Astrophysics Data System (ADS)

    Chiu, Jeng-Lun; Chang, H.; Boggs, S. E.; NCT Collaboration

    2012-05-01

    The Nuclear Compton Telescope (NCT) is a balloon-borne soft gamma ray (0.2-10 MeV) telescope designed to study astrophysical sources of nuclear line emission and polarization. The heart of NCT is a compact array of 12 cross-strip germanium detectors (GeDs), providing high spectral resolution ( 0.3-0.9% FWHM at 662 keV for most channels) and capability of tracking each photon interaction with full 3D position resolution to 2 mm3. NCT has flown successfully on two conventional balloon flights to date, and the Crab Nebula was detected at a significance of 4σ in the second flight, which occurred on 2009 May 17 and 18 in Fort Sumner, New Mexico. Here approximately 38 ks of background measurements in the second flight is studied from ground altitude to average float altitude (1.2-40 km). We discuss the expected contributions to the background component through detailed Monte Carlo simulations. Complete depth dependent environmental inputs are introduced, considering cosmic and atmospheric photon distributions, primary cosmic rays (protons), cosmic ray secondaries (protons and neutrons), and activation induced components. Imaging of the 511 keV annihilation line from the background is also attempted.

  16. Nuclear radiation-warning detector that measures impedance

    SciTech Connect

    Savignac, Noel Felix; Gomez, Leo S; Yelton, William Graham; Robinson, Alex; Limmer, Steven

    2013-06-04

    This invention is a nuclear radiation-warning detector that measures impedance of silver-silver halide on an interdigitated electrode to detect light or radiation comprised of alpha particles, beta particles, gamma rays, X rays, and/or neutrons. The detector is comprised of an interdigitated electrode covered by a layer of silver halide. After exposure to alpha particles, beta particles, X rays, gamma rays, neutron radiation, or light, the silver halide is reduced to silver in the presence of a reducing solution. The change from the high electrical resistance (impedance) of silver halide to the low resistance of silver provides the radiation warning that detected radiation levels exceed a predetermined radiation dose threshold.

  17. EPR g factors and defect structures for V4+ and Cr5+ in the rutile-type crystals

    NASA Astrophysics Data System (ADS)

    Wang, Minjie; Zhu, Lianxuan

    2016-08-01

    The g-factor formulas for V4+ and Cr5+ ions in the rutile-type crystals are deduced from Jahn-Teller effect and contributions of the charge transfer levels. The tetragonal distortions ΔR = -0.0045, -0.0045 and -0.0067 nm, and Δθ = 0°, -0.001° and 0°, for GeO2:V4+, TiO2:V4+ and TiO2:Cr5+, respectively. The calculations of the g-factors agree well with the experimental values. The contributions of the charge transfer levels to g factors increase with the increasing valence state. It must be taken into account in the precise calculations of g factors for the high valence state d1 ions in crystals.

  18. In-Pile Thermal Conductivity Measurement Method for Nuclear Fuels

    SciTech Connect

    Joy L. Rempe; Brandon Fox; Heng Ban; Joshua E. Daw; Darrell L. Knudson; Keith G. Condie

    2009-08-01

    Thermophysical properties of advanced nuclear fuels and materials during irradiation must be known prior to their use in existing, advanced, or next generation reactors. Thermal conductivity is one of the most important properties for predicting fuel and material performance. A joint Utah State University (USU) / Idaho National Laboratory (INL) project, which is being conducted with assistance from the Institute for Energy Technology at the Norway Halden Reactor Project, is investigating in-pile fuel thermal conductivity measurement methods. This paper focuses on one of these methods – a multiple thermocouple method. This two-thermocouple method uses a surrogate fuel rod with Joule heating to simulate volumetric heat generation to gain insights about in-pile detection of thermal conductivity. Preliminary results indicated that this method can measure thermal conductivity over a specific temperature range. This paper reports the thermal conductivity values obtained by this technique and compares these values with thermal property data obtained from standard thermal property measurement techniques available at INL’s High Test Temperature Laboratory. Experimental results and material properties data are also compared to finite element analysis results.

  19. Experiments and nuclear measurements in search of cold fusion processes

    NASA Astrophysics Data System (ADS)

    Gottesfeld, S.; Anderson, R. E.; Baker, D. A.; Bolton, R. D.; Butterfield, K. B.; Garzon, F. H.; Goulding, C. A.; Johnson, M. W.; Leonard, E. M.; Springer, T. E.; Zawodzinski, T.

    1990-09-01

    This paper reports a collaborative effort of a team which formed at Los Alamos to investigate the announcement that “cold fusion” may be occurring in electrochemical cells using palladium cathodes and platinum anodes in a LiOD electrolyte. Four electrochemical cells were construced and operated for 3-5 weeks under various geometrical and electrical conditions. Nuclear diagnostic measurements included high and low resolution gamma-ray spectroscopy, integral neutron counting with well detectors and banks of3He tubes, and neutron spectroscopy with NE-213 scintillators. For one of the cells, the deuterium loading of the cathode was determined from resistance measurements to be D/Pd⩽ 0.8. No conclusive evidence was found for the production of neutrons or 2.223-MeV gammas above levels consistent with background. The results of the measurements of tritium levels in the cell electrolytes are also reported. Experiments to reproduce the observation of neutrons from high pressure Ti- D 2 gas experiments were also performed with negative results.

  20. Measurement of doses to the extremities of nuclear medicine staff

    NASA Astrophysics Data System (ADS)

    Shousha, Hany A.; Farag, Hamed; Hassan, Ramadan A.

    2010-01-01

    Medical uses of ionizing radiation now represent>95% of all man-made radiation exposure, and is the largest single radiation source after natural background radiation. Therefore, it is important to quantify the amount of radiation received by occupational individuals to optimize the working conditions for staff, and further, to compare doses in different departments to ensure compatibility with the recommended standards. For some groups working with unsealed sources in nuclear medicine units, the hands are more heavily exposed to ionizing radiation than the rest of the body. A personal dosimetry service runs extensively in Egypt. But doses to extremities have not been measured to a wide extent. The purpose of this study was to investigate the equivalent radiation doses to the fingers for five different nuclear medicine staff occupational groups for which heavy irradiation of the hands was suspected. Finger doses were measured for (1) nuclear medicine physicians, (2) technologists, (3) nurses and (4) physicists. The fifth group contains three technicians handling 131I, while the others handled 99mTc. Each staff member working with the radioactive material wore two thermoluminescent dosimeters (TLDs) during the whole testing period, which lasted from 1 to 4 weeks. Staff performed their work on a regular basis throughout the month, and mean annual doses were calculated for these groups. Results showed that the mean equivalent doses to the fingers of technologist, nurse and physicist groups were 30.24±14.5, 30.37±17.5 and 16.3±7.7 μSv/GBq, respectively. Equivalent doses for the physicians could not be calculated per unit of activity because they did not handle the radiopharmaceuticals directly. Their doses were reported in millisieverts (mSv) that accumulated in one week. Similarly, the dose to the fingers of individuals in Group 5 was estimated to be 126.13±38.2 μSv/GBq. The maximum average finger dose, in this study, was noted in the technologists who handled

  1. Measurement of doses to the extremities of nuclear medicine staff

    NASA Astrophysics Data System (ADS)

    Shousha, Hany A.; Farag, Hamed; Hassan, Ramadan A.

    Medical uses of ionizing radiation now represent>95% of all man-made radiation exposure, and is the largest single radiation source after natural background radiation. Therefore, it is important to quantify the amount of radiation received by occupational individuals to optimize the working conditions for staff, and further, to compare doses in different departments to ensure compatibility with the recommended standards. For some groups working with unsealed sources in nuclear medicine units, the hands are more heavily exposed to ionizing radiation than the rest of the body. A personal dosimetry service runs extensively in Egypt. But doses to extremities have not been measured to a wide extent. The purpose of this study was to investigate the equivalent radiation doses to the fingers for five different nuclear medicine staff occupational groups for which heavy irradiation of the hands was suspected. Finger doses were measured for (1) nuclear medicine physicians, (2) technologists, (3) nurses and (4) physicists. The fifth group contains three technicians handling 131I, while the others handled 99mTc. Each staff member working with the radioactive material wore two thermoluminescent dosimeters (TLDs) during the whole testing period, which lasted from 1 to 4 weeks. Staff performed their work on a regular basis throughout the month, and mean annual doses were calculated for these groups. Results showed that the mean equivalent doses to the fingers of technologist, nurse and physicist groups were 30.24±14.5, 30.37±17.5 and 16.3±7.7 μSv/GBq, respectively. Equivalent doses for the physicians could not be calculated per unit of activity because they did not handle the radiopharmaceuticals directly. Their doses were reported in millisieverts (mSv) that accumulated in one week. Similarly, the dose to the fingers of individuals in Group 5 was estimated to be 126.13±38.2 μSv/GBq. The maximum average finger dose, in this study, was noted in the technologists who handled

  2. Fundamental Symmetries Probed by Precision Nuclear Mass Measurements at ISOLTRAP

    NASA Astrophysics Data System (ADS)

    Bollen, Georg

    2005-04-01

    Mass measurements on rare isotopes can play an important role in testing the nature of fundamental interactions. Precise mass values together with decay data are required for critical tests of the conserved vector current (CVC) hypothesis and the standard model. Substantial progress in Penning trap mass spectrometry has made this technique the best choice for precision measurements on rare isotopes, by providing high accuracy and sensitivity even for short-lived nuclides. The pioneering facility in this field is ISOLTRAP at ISOLDE/CERN. ISOLTRAP is a mass spectrometer capable to determine nuclear binding energies with an uncertainty of 10-8 on nuclides that are produced with yields as low as a few 100 ions/s and at half-lives well below 100 ms. It is used for mass measurements relevant for a better understanding of nuclear structure and the nucleosynthesis of the elements. It is also used for the determination of masses that are important for the test of CVC, the unitary of the Cabibbo-Kobayashi-Maskawa (CKM) matrix, and for putting constrains on the existence of scalars currents. Measurements along this line include ^74Rb (T1/2=65 ms), which is the shortest-lived nuclide studied in a Penning trap. The QEC values of ^74Rb, determined with a precision of 6.10-8, serves as a test of CVC or of related theoretical corrections [1]. Masses of ^32Ar and ^33Ar have been determined with uncertainties of 6.0 . 10-8 and 1.4 . 10-8 [2]. The improved mass for ^32Ar helps to provide a better constraint on scalar contributions to the weak interaction and both argon data serve as the most stringent test of isobaric multiplet mass equation IMME. ^34Ar, another CVC test candidate, has been studied with an uncertainty of 1.1.10-8 (δm = 0.41 keV). Similar precision has been achieved for ^22Mg and neighboring ^21Na and ^22Na [4]. The importance of these results is twofold: First, an Ft value has been obtained for the super-allowed β decay of ^22Mg to further test the CVC hypothesis

  3. The G-factor as a tool to learn more about bone structure and function.

    PubMed

    Zerath, E

    1999-07-01

    In normal life on earth, the locomotor system is exposed to two types of stimulation: gravity (passive stimulation) and motion (active stimulation). Both permanently combine, and the interactions between locomotion and gravity induce an overall recruitment which is repeated daily and maintains the bone tissue structure within the range of constraints to which it is adapted. This range is one of the basic hypotheses underlying the mechanical concepts of bone structure control, and it has been considered as logical to assume that weightlessness of spaceflight should produce bone loss since astronauts are outside of the terrestrial gravitational field of forces, no longer relying on muscular work to change positions or move. But, thirty years after the first changes in phospho-calcium metabolism were observed in astronauts after spaceflight, current knowledge does not provide a full understanding of this pathogeny, and prove the G-factor is now considered as an essential component of the experimental tools available to study bone physiology. The study of the physiology of bone tissue usually consists in the investigation of its two fundamental roles, i.e. reservoir of inorganic elements (calcium, phosphorus, magnesium) and mechanical support for soft tissues. Together with the combined action of muscles, tendons, and ligaments, this support permits motion and locomotion. These two functions rely on a sophisticated bone tissue architecture, and on the adaptability of this structure, with modeling and remodeling processes, themselves associated with the coupled activity of specialized bone cell populations. PMID:11543035

  4. Superconducting quantum spin-Hall systems with giant orbital g-factors

    NASA Astrophysics Data System (ADS)

    Hankiewicz, Ewelina; Reinthaler, Rolf; Tkachov, Grigory

    Topological aspects of superconductivity in quantum spin-Hall systems (QSHSs) such as thin layers of three-dimensional topological insulators (3D Tis) or two-dimensional Tis are in the focus of current research. Here, we describe a novel superconducting quantum spin-Hall effect (quantum spin Hall system in the proximity to the s-wave superconductor and in the orbital in-plane magnetic field), which is protected against elastic backscattering by combined time-reversal and particle-hole symmetry. This effect is characterized by spin-polarized edge states, which can be manipulated in weak magnetic fields due to a giant effective orbital g-factor, allowing the generation of spin currents. The phenomenon provides a novel solution to the outstanding challenge of detecting the spin-polarization of the edge states. Here we propose the detection of the edge polarization in the three-terminal junction using unusual transport properties of superconducting quantum Hall-effect: a non-monotonic excess current and a zero-bias conductance splitting. We thank for the financial support the German Science Foundation (DFG), Grants No HA 5893/4-1 within SPP 1666, HA5893/5-2 within FOR1162 and TK60/1-1 (G.T.), as well the ENB graduate school ``Topological insulators''.

  5. Nuclear magnetic resonance and transcutaneous electromagnetic blood flow measurement.

    PubMed

    Battocletti, J H; Halbach, R E; Salles-Cunha, S X; Sances, A

    1983-09-01

    Static and alternating magnetic fields are employed in blood flowmeters using nuclear magnetic resonance (NMR) principles and electromagnetic induction by a moving conductor (TEM). Both techniques require high steady magnetic fields, obtained either from permanent magnets or from electromagnets. A relatively homogeneous magnetic field is needed for NMR, but, though important for calibration, homogeneity is not critical for TEM. NMR is more complex than TEM since it requires radio-frequency and audio-frequency magnetic fields. However, the TEM method requires surface electrodes in contact with the skin, or needle electrodes placed subcutaneously, whereas NMR is contactless. The NMR flowmeter can be calibrated directly, but appropriate and approximate models must be assumed and then solved by computer to quantify blood flow by the TEM flowmeter. Flow in individual vessels is measured a priori in the TEM flowmeter by virtue of the assumed models. To measure flow in individual vessels by NMR, a scanning or ranging method is required, which logically leads to blood flow imaging. The levels of steady, radio-frequency, and audio-frequency magnetic fields used in the two types of flowmeters are low enough so as not to cause any apparent stimulus to human volunteers and patients tested. PMID:6228667

  6. g-factor and spin-parity assignments of excited states in the N=83 isotones {sup 135}Te, {sup 136}I, {sup 137}Xe, and {sup 138}Cs

    SciTech Connect

    Liu, S. H.; Hamilton, J. H.; Ramayya, A. V.; Hwang, J. K.; Covello, A.; Itaco, N.; Gargano, A.; Stone, N. J.; Daniel, A. V.; Luo, Y. X.; Rasmussen, J. O.; Ter-Akopian, G. M.; Zhu, S. J.; Ma, W. C.

    2010-01-15

    The g factor of the 15/2{sup -} state in {sup 137}Xe was measured for the first time by using a newly developed technique for measuring angular correlations with Gammasphere. Spins and parities were assigned to several levels in the N=83 isotones {sup 135}Te, {sup 136}I, {sup 137}Xe, and {sup 138}Cs. The calculated g factor in the shell-model frame is in good agreement with the measured one in the present work. Shell-model calculations also support our spin-parity assignments.

  7. Review of nuclear data improvement needs for nuclear radiation measurement techniques used at the CEA experimental reactor facilities

    NASA Astrophysics Data System (ADS)

    Destouches, Christophe

    2016-03-01

    The constant improvement of the neutron and gamma calculation codes used in experimental nuclear reactors goes hand in hand with that of the associated nuclear data libraries. The validation of these calculation schemes always requires the confrontation with integral experiments performed in experimental reactors to be completed. Nuclear data of interest, straight as cross sections, or elaborated ones such as reactivity, are always derived from a reaction rate measurement which is the only measurable parameter in a nuclear sensor. So, in order to derive physical parameters from the electric signal of the sensor, one needs specific nuclear data libraries. This paper presents successively the main features of the measurement techniques used in the CEA experimental reactor facilities for the on-line and offline neutron/gamma flux characterizations: reactor dosimetry, neutron flux measurements with miniature fission chambers and Self Power Neutron Detector (SPND) and gamma flux measurements with chamber ionization and TLD. For each technique, the nuclear data necessary for their interpretation will be presented, the main identified needs for improvement identified and an analysis of their impact on the quality of the measurement. Finally, a synthesis of the study will be done.

  8. Nuclear Resonance Fluorescence to Measure Plutonium Mass in Spent Nuclear Fuel

    SciTech Connect

    Ludewigt, Bernhard A; Quiter, Brian J.; Ambers, Scott D.

    2011-01-14

    The Next Generation Safeguard Initiative (NGSI) of the U.S Department of Energy is supporting a multi-lab/university collaboration to quantify the plutonium (Pu) mass in spent nuclear fuel (SNF) assemblies and to detect the diversion of pins with non-destructive assay (NDA) methods. The following 14 NDA techniques are being studied: Delayed Neutrons, Differential Die-Away, Differential Die-Away Self-Interrogation, Lead Slowing Down Spectrometer, Neutron Multiplicity, Passive Neutron Albedo Reactivity, Total Neutron (Gross Neutron), X-Ray Fluorescence, {sup 252}Cf Interrogation with Prompt Neutron Detection, Delayed Gamma, Nuclear Resonance Fluorescence, Passive Prompt Gamma, Self-integration Neutron Resonance Densitometry, and Neutron Resonance Transmission Analysis. Understanding and maturity of the techniques vary greatly, ranging from decades old, well-understood methods to new approaches. Nuclear Resonance Fluorescence (NRF) is a technique that had not previously been studied for SNF assay or similar applications. Since NRF generates isotope-specific signals, the promise and appeal of the technique lies in its potential to directly measure the amount of a specific isotope in an SNF assay target. The objectives of this study were to design and model suitable NRF measurement methods, to quantify capabilities and corresponding instrumentation requirements, and to evaluate prospects and the potential of NRF for SNF assay. The main challenge of the technique is to achieve the sensitivity and precision, i.e., to accumulate sufficient counting statistics, required for quantifying the mass of Pu isotopes in SNF assemblies. Systematic errors, considered a lesser problem for a direct measurement and only briefly discussed in this report, need to be evaluated for specific instrument designs in the future. Also, since the technical capability of using NRF to measure Pu in SNF has not been established, this report does not directly address issues such as cost, size

  9. Potential cooperative measures on nuclear issues in Asia

    SciTech Connect

    Olsen, J.

    1997-08-01

    Cooperation on nuclear issues is receiving increased attention in Asia. In Northeast Asia, where the nuclear industry is well-developed, cooperation in the back end of the nuclear fuel cycle could help deal with issues such as disposition of spent fuel and long term storage options. In Southeast Asia, where countries are just beginning to introduce nuclear energy, cooperation would be useful in developing standards for the nuclear industry. Throughout Asia, nuclear research and power activities can raise concerns about safety, environmental pollution and proliferation. The sharing of relevant information, i.e. cooperative monitoring, will be essential to addressing these issues. In fact, a number of regional interactions on nuclear issues are already occurring. These range from training exchanges sponsored by the more advanced states to participation in environmental monitoring of the East Sea (Sea of Japan). Several states are considering sharing information from their nuclear facilities; some exchanges of radiation data are already in place. The KEDO reactor project will involve close working relations between the nuclear experts of South Korea, North Korea, Japan, and the US. Areas for further regional cooperation are discussed.

  10. Exchange enhancement of the electron g-factor in a two-dimensional semimetal in HgTe quantum wells

    SciTech Connect

    Bovkun, L. S. Krishtopenko, S. S.; Zholudev, M. S.; Ikonnikov, A. V.; Spirin, K. E.; Dvoretsky, S. A.; Mikhailov, N. N.; Teppe, F.; Knap, W.; Gavrilenko, V. I.

    2015-12-15

    The exchange enhancement of the electron g-factor in perpendicular magnetic fields to 12 T in HgTe/CdHgTe quantum wells 20 nm wide with a semimetal band structure is studied. The electron effective mass and g-factor at the Fermi level are determined by analyzing the temperature dependence of the amplitude of Shubnikov–de Haas oscillation in weak fields and near odd Landau-level filling factors ν ≤ 9. The experimental values are compared with theoretical calculations performed in the one-electron approximation using the eight-band kp Hamiltonian. The found dependence of g-factor enhancement on the electron concentration is explained by changes in the contributions of hole- and electron-like states to exchange corrections to the Landau-level energies in the conduction band.

  11. Δg: The new aromaticity index based on g-factor calculation applied for polycyclic benzene rings

    NASA Astrophysics Data System (ADS)

    Ucun, Fatih; Tokatlı, Ahmet

    2015-02-01

    In this work, the aromaticity of polycyclic benzene rings was evaluated by the calculation of g-factor for a hydrogen placed perpendicularly at geometrical center of related ring plane at a distance of 1.2 Å. The results have compared with the other commonly used aromatic indices, such as HOMA, NICSs, PDI, FLU, MCI, CTED and, generally been found to be in agreement with them. So, it was proposed that the calculation of the average g-factor as Δg could be applied to study the aromaticity of polycyclic benzene rings without any restriction in the number of benzene rings as a new magnetic-based aromaticity index.

  12. Dependence of Berry's phase for atom on a sign of the g factor in the rotating magnetic field

    SciTech Connect

    Morinaga, Atsuo; Aoki, Takatoshi; Yasuhara, Makoto

    2005-05-15

    Berry's phase of the atom in the state with a positive or negative g factor for partial cycles of a rotating magnetic field was determined free from the dynamical phase shift using a time-domain atom interferometer. The experimental phase shift is in good agreement with the prediction of Berry's phase for partial cycles. It was found that the sense of Berry's phase depends on the sign of the magnetic quantum number, the sense of the rotating magnetic field, and the sign of the g factor of the state.

  13. Uncertainties for criticality-safety benchmarks and consequences for nuclear data measurements

    NASA Astrophysics Data System (ADS)

    Rochman, D.; Koning, A. J.; van der Marck, S. C.

    2009-10-01

    We have developed a new method to propagate the uncertainties of fundamental nuclear physics models and parameters used in nuclear data evaluation to the design and performance of future nuclear energy systems. Using Monte Carlo simulation, it is for the first time possible to couple these two fields at the extremes of nuclear science without any loss of information in between. With the help of a large database of nuclear reaction measurements, we have determined the uncertainties of theoretical nuclear reaction models such as the optical, compound nucleus, pre-equilibrium and fission models. A similar assessment is done for the parameters that describe the resolved resonance range. We are now able to quantify the required quality of theoretical nuclear reaction models and measurements directly from the reactor design requirements. Examples will be presented for actinides using criticality-safety benchmarks with feedback on experimental requirements.

  14. G factor of the 2/sub 1//sup +/ state in /sup 140/Ba and /sup 142/Ba

    SciTech Connect

    Pauling, L.

    1987-06-01

    A simple calculation on the basis of the revolving cluster model leads to the value 0.495 for the g factor of /sub //sub <1/ /sub 56//sup 42/Ba/sub 86/, in agreement with the experimental value 0.48 +- 0.14. The same value is predicted for /sup 140/Ba.

  15. Measurement of Nuclear Dependence in Inclusive Charged Current Neutrino Scattering

    SciTech Connect

    Tice, Brian George

    2014-01-01

    Neutrino experiments use heavy nuclei (C, Fe, Pb) to achieve necessary statistics. However, the use of heavy nuclei exposes these experiments to the nuclear dependence of neutrino-nucleus cross sections, which are poorly known and difficult to model. This dissertation presents an analysis of the nuclear dependence of inclusive chargedcurrent neutrino scattering using events in carbon, iron, lead, and scintillator targets of the MINERvA detector. MINERvA (Main INjector ExpeRiment for -A) is a few-GeV neutrinonucleus scattering experiment at Fermilab.

  16. Tuning the electrically evaluated electron Landé g factor in GaAs quantum dots and quantum wells of different well widths

    NASA Astrophysics Data System (ADS)

    Allison, G.; Fujita, T.; Morimoto, K.; Teraoka, S.; Larsson, M.; Kiyama, H.; Oiwa, A.; Haffouz, S.; Austing, D. G.; Ludwig, A.; Wieck, A. D.; Tarucha, S.

    2014-12-01

    We evaluate the Landé g factor of electrons in quantum dots (QDs) fabricated from GaAs quantum well (QW) structures of different well width. We first determine the Landé electron g factor of the QWs through resistive detection of electron spin resonance and compare it to the enhanced electron g factor determined from analysis of the magnetotransport. Next, we form laterally defined quantum dots using these quantum wells and extract the electron g factor from analysis of the cotunneling and Kondo effect within the quantum dots. We conclude that the Landé electron g factor of the quantum dot is primarily governed by the electron g factor of the quantum well suggesting that well width is an ideal design parameter for g -factor engineering QDs.

  17. Synergistic smart fuel for in-pile nuclear reactor measurements

    SciTech Connect

    Smith, J.A.; Kotter, D.K.; Ali, R.A.; Garrett, S.L.

    2013-07-01

    The thermo-acoustic fuel rod sensor developed in this research has demonstrated a novel technique for monitoring the temperature within the core of a nuclear reactor or the temperature of the surrounding heat-transfer fluid. It uses the heat from the nuclear fuel to generate sustained acoustic oscillations whose frequency will be indicative of the temperature. Converting a nuclear fuel rod into this type of thermo-acoustic sensor simply requires the insertion of a porous material (stack). This sensor has demonstrated a synergy with the elevated temperatures that exist within the nuclear reactor using materials that have only minimal susceptibility to high-energy particle fluxes. When the sensor is in operation, the sound waves radiated from the fuel rod resonator will propagate through the surrounding cooling fluid. The frequency of these oscillations is directly correlated with an effective temperature within the fuel rod resonator. This device is self-powered and is operational even in case of total loss of power of the reactor.

  18. Computing the Kirkwood g-Factor by Combining Constant Maxwell Electric Field and Electric Displacement Simulations: Application to the Dielectric Constant of Liquid Water.

    PubMed

    Zhang, Chao; Hutter, Jürg; Sprik, Michiel

    2016-07-21

    In his classic 1939 paper, Kirkwood linked the macroscopic dielectric constant of polar liquids to the local orientational order as measured by the g-factor (later named after him) and suggested that the corresponding dielectric constant at short-range is effectively equal to the macroscopic value just after "a distance of molecular magnitude" [ Kirkwood, J. Chem. Phys., 1939, 7, 911 ]. Here, we show a simple approach to extract the short-ranged Kirkwood g-factor from molecular dynamics (MD) simulation by superposing the outcomes of constant electric field E and constant electric displacement D simulations [ Zhang and Sprik, Phys. Rev. B: Condens. Matter Mater. Phys., 2016, 93, 144201 ]. Rather than from the notoriously slow fluctuations of the dipole moment of the full MD cell, the dielectric constant can now be estimated from dipole fluctuations at short-range, accelerating the convergence. Exploiting this feature, we computed the bulk dielectric constant of liquid water modeled in the generalized gradient approximation (PBE) to density functional theory and found it to be at least 40% larger than the experimental value. PMID:27352038

  19. Synergistic Smart Fuel For In-pile Nuclear Reactor Measurements

    SciTech Connect

    James A. Smith; Dale K. Kotter; Randall A. Ali; Steven L . Garrett

    2013-10-01

    In March 2011, an earthquake of magnitude 9.0 on the Richter scale struck Japan with its epicenter on the northeast coast, near the Tohoku region. In addition to the immense physical destruction and casualties across the country, several nuclear power plants (NPP) were affected. It was the Fukushima Daiichi NPP that experienced the most severe and irreversible damage. The earthquake brought the reactors at Fukushima to an automatic shutdown and because the power transmission lines were damaged, emergency diesel generators (EDGs) were activated to ensure that there was continued cooling of the reactors and spent fuel pools. The situation was being successfully managed until the tsunami hit about forty-five minutes later with a maximum wave height of approximately 15 m. The influx of water submerged the EDGs, the electrical switchgear, and dc batteries, resulting in the total loss of power to the reactors.2 At this point, the situation became critical. There was a loss of the sensors and instrumentation within the reactor that could have provided valuable information to guide the operators to make informed decisions and avoid the unfortunate events that followed. In the light of these events, we have developed and tested a potential self-powered thermoacoustic system, which will have the ability to serve as a temperature sensor and can transmit data independently of electronic networks. Such a device is synergistic with the harsh environment of the nuclear reactor as it utilizes the heat from the nuclear fuel to provide the input power.

  20. 78 FR 55765 - Compensatory and Alternative Regulatory Measures for Nuclear Power Plant Fire Protection (CARMEN...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-11

    ... (78 FR 45573) a request for public comment on NUREG/CR-7135, ``Compensatory and Alternative Regulatory... COMMISSION Compensatory and Alternative Regulatory Measures for Nuclear Power Plant Fire Protection (CARMEN-FIRE) AGENCY: Nuclear Regulatory Commission. ACTION: Draft NUREG/CR, reopening of comment...

  1. Calculation of EPR Parameters g Factors for Ce3+ Ion in YBa2Cu3O6+x Superconductor

    NASA Astrophysics Data System (ADS)

    Dong, Hui-Ning; Du, Hui-Ping; Duan, Chang-Kui; Luo, Xiao-Bing

    The perturbation formulae of EPR parameters g factors gx, gy and gz for the lowest Kramers doublet of 4f1 ion in orthorhombic symmetry are established. In these formulae, the contributions of the covalency effects, the admixture between J=7/2 and J=5/2 states as well as the second-order perturbation (which is not considered in the previous works) via crystal-field and orbital angular momentum interactions are all included. According to these formulae, and by using the superposition model, the g-factors gx, gy and gz for Ce3+ center in YBa2Cu3O6+x superconductor are calculated. The results are discussed.

  2. Confirmatory Factor Analysis of Project Spectrum Activities. A Second-Order "g" Factor or Multiple Intelligences?

    ERIC Educational Resources Information Center

    Castejon, Juan L.; Perez, Antonio M.; Gilar, Raquel

    2010-01-01

    This paper compares different theoretical models of the structure of intelligence, based on the analysis of data obtained in a series of measured abilities corresponding to the Spectrum assessment activities (Gardner, Feldman & Krechevsky, 1998) in a sample of 393 children enrolled in kindergarten and first grade. The data were analyzed using…

  3. Finding the "g"-Factor in Brain Structure Using the Method of Correlated Vectors

    ERIC Educational Resources Information Center

    Colom, Roberto; Jung, Rex E.; Haier, Richard J.

    2006-01-01

    It is unclear whether brain mechanisms underlying human intelligence are distributed throughout the brain or mainly concentrated in the frontal lobes. Data are inconsistent possibly due, at least in part, to the different ways the construct of intelligence is measured. Here we apply the method of correlated vectors to determine how the general…

  4. Wave Function Mixing and g-Factors in Narrow Gap Ferromagnetic III-V Dilute Magnetic Semiconductors

    NASA Astrophysics Data System (ADS)

    Sun, Y.; Sanders, G. D.; Stanton, C. J.

    2002-03-01

    We present a theory for wave-function mixing and g-factors in ferromagnetic p-doped narrow gap In_1-xMn_xAs dilute magnetic semiconductor alloys in an ultrahigh external magnetic field, B. We generalize an 8 band Pidgeon-Brown model to include (i) the wavevector, k, dependence of the electronic states along B, (ii) s-d and p-d exchange interactions with localized Mn d-electrons, and (iii) finite magnetic moment in the ferromagnetic state. The complex valence band structure at finite k plays an important role in the cyclotron resonance spectra. We look at the band-mixing and spin-dependence of the wave functions as a function of the wavevector, magnetic field (0-100T), temperature (4 K to 290 K), and Mn concentration (0 to 12 %). From this, we can extract magnetic field dependent g-factors. The sensitivity of the band mixing and g-factors to the s-d and p-d exchange interactions is also investigated. Finally, we look at the effect of band-mixing on optical properties such as the polarization dependence of the absorption and luminescence.

  5. Calculation of the g Factors and Local Angular Distortions for ZnO:Cu2+ Nanocrystals With Various Copper Concentrations

    NASA Astrophysics Data System (ADS)

    Li, G.-L.; Wu, S.-Y.; Hu, X.-F.; Teng, B.-H.; Wu, M.-H.

    2016-07-01

    Based on the perturbation treatments for a tetragonally distorted tetrahedral 3d 9 cluster, the g factors and local angular distortions are calculated for ZnO:Cu2+ nanocrystals with various Cu2+ concentrations in different systems I and II under dissimilar experimental conditions. Because of the dynamic Jahn-Teller effect, the bond angles θ between the four equivalent Cu2+-O2- bonds and the C4 axis are about 1.5o larger than that (θ0 ≈ 54.736o) of an ideal tetrahedron. Consequently, the original slightly trigonally distorted oxygen tetrahedron of the host Zn2+ site is transformed into a tetragonally compressed one. The isotropy of g factors may be attributed to the appropriate angular distortions Δθ = θ - θ0 due to the dynamic Jahn-Teller effect. The slightly increasing (or decreasing) g factors with concentration x can be illustrated as the delicate increases (or decreases) of the angular distortions (Δθ) and the covalency factors (N) for system I (or II), respectively, under almost equivalent crystal-fi eld strengths (Dq).

  6. Rapid flow cytometric measurement of protein inclusions and nuclear trafficking

    PubMed Central

    Whiten, D. R.; San Gil, R.; McAlary, L.; Yerbury, J. J.; Ecroyd, H.; Wilson, M. R.

    2016-01-01

    Proteinaceous cytoplasmic inclusions are an indicator of dysfunction in normal cellular proteostasis and a hallmark of many neurodegenerative diseases. We describe a simple and rapid new flow cytometry-based method to enumerate, characterise and, if desired, physically recover protein inclusions from cells. This technique can analyse and resolve a broad variety of inclusions differing in both size and protein composition, making it applicable to essentially any model of intracellular protein aggregation. The method also allows rapid quantification of the nuclear trafficking of fluorescently labelled molecules. PMID:27516358

  7. Measurement of the nuclear energy loss under channeling

    NASA Astrophysics Data System (ADS)

    Winter, H.; Mertens, A.

    2001-07-01

    Neutral Ne atoms with keV energies are scattered under channeling conditions, i.e. at a glancing angle of incidence, from a LiF(001) surface. By means of a time-of-flight method with a pulsed neutral beam we record energy distributions for scattered projectiles. For this specific system the small energy transferred to the crystal lattice ("nuclear energy loss") during channeling via binary collisions with large impact parameters dominates the dissipation of projectile energy. All other excitations of the solid can be brought to a negligible level.

  8. Rapid flow cytometric measurement of protein inclusions and nuclear trafficking.

    PubMed

    Whiten, D R; San Gil, R; McAlary, L; Yerbury, J J; Ecroyd, H; Wilson, M R

    2016-01-01

    Proteinaceous cytoplasmic inclusions are an indicator of dysfunction in normal cellular proteostasis and a hallmark of many neurodegenerative diseases. We describe a simple and rapid new flow cytometry-based method to enumerate, characterise and, if desired, physically recover protein inclusions from cells. This technique can analyse and resolve a broad variety of inclusions differing in both size and protein composition, making it applicable to essentially any model of intracellular protein aggregation. The method also allows rapid quantification of the nuclear trafficking of fluorescently labelled molecules. PMID:27516358

  9. Hydrogen release from irradiated elastomers measured by Nuclear Reaction Analysis

    NASA Astrophysics Data System (ADS)

    Jagielski, J.; Ostaszewska, U.; Bielinski, D. M.; Grambole, D.; Romaniec, M.; Jozwik, I.; Kozinski, R.; Kosinska, A.

    2016-03-01

    Ion irradiation appears as an interesting method of modification of elastomers, especially friction and wear properties. Main structural effect caused by heavy ions is a massive loss of hydrogen from the surface layer leading to its smoothening and shrinking. The paper presents the results of hydrogen release from various elastomers upon irradiation with H+, He+ and Ar+ studied by using Nuclear Reaction Analysis (NRA) method. The analysis of the experimental data indicates that the hydrogen release is controlled by inelastic collisions between ions and target electrons. The last part of the study was focused on preliminary analysis of mechanical properties of irradiated rubbers.

  10. Nuclear-resonance magnetometer with flowing liquid for superstrong inhomogeneous fields measuring

    NASA Astrophysics Data System (ADS)

    Davydov, V. V.; Dudkin, V. I.; Vologdin, V. A.

    2016-03-01

    Multichannel nuclear-resonance magnetometer for remote monitoring of induction and heterogeneity of a magnetic field in different areas inside and near a charged particle accelerator is considered. The maximal distance between the nuclear magnetic resonance signal detector and the magnetometer is 50 m. Measurement error is 0.5%, sensitivity of the magnetometer is 10-10 T/Hz1/2, measurement time of the magnetic field parameters in 24 control points is no more than 4 minutes.

  11. Observation of Optical Chemical Shift by Precision Nuclear Spin Optical Rotation Measurements and Calculations.

    PubMed

    Shi, Junhui; Ikäläinen, Suvi; Vaara, Juha; Romalis, Michael V

    2013-02-01

    Nuclear spin optical rotation (NSOR) is a recently developed technique for detection of nuclear magnetic resonance via rotation of light polarization, instead of the usual long-range magnetic fields. NSOR signals depend on hyperfine interactions with virtual optical excitations, giving new information about the nuclear chemical environment. We use a multipass optical cell to perform the first precision measurements of NSOR signals for a range of organic liquids and find clear distinction between proton signals for different compounds, in agreement with our earlier theoretical predictions. Detailed first-principles quantum mechanical NSOR calculations are found to be in agreement with the measurements. PMID:26281737

  12. Application of American National Standards of calibration techniques of bulk measurements for nuclear materials control

    SciTech Connect

    Doher, L. W.; Gerald, K. B.

    1980-01-01

    In 1975 Subcommittee ANSI-INMM-8, Calibration Techniques for Nuclear Material Control under the guidance of the American National Standards Institute Committee N15 and sponsored by the Institute of Nuclear Materials Management, published four standards for calibration of bulk measurement of nuclear materials. The calibration techniques include those for mass, volume, nondestructive assay, and plutonium calorimetry measurements. Since that time, calibration and research personnel of the Rocky Flats Plant and workers at other facilities have applied the direction and guidance of these standards. Results of the applications are reported and th value of each standard discussed. Examples are included together with certain shortcomings and future revision plans.

  13. Projective measurement of a single nuclear spin qubit by using two-mode cavity QED.

    PubMed

    Eto, Yujiro; Noguchi, Atsushi; Zhang, Peng; Ueda, Masahito; Kozuma, Mikio

    2011-04-22

    We report the implementation of projective measurement on a single 1/2 nuclear spin of the (171)Yb atom by measuring the polarization of cavity-enhanced fluorescence. To obtain cavity-enhanced fluorescence having a nuclear-spin-dependent polarization, we construct a two-mode cavity QED system, in which two cyclic transitions are independently coupled to each of the orthogonally polarized cavity modes, by manipulating the energy level of (171)Yb. This system can associate the nuclear spin degrees of freedom with the polarization of photons, which will facilitate the development of hybrid quantum systems. PMID:21599343

  14. Passive Measurement of Organic-Scintillator Neutron Signatures for Nuclear Safeguards Applications

    SciTech Connect

    Jennfier L. Dolan; Eric C. Miller; Alexis C. Kaplan; Andreas Enqvist; Marek Flaska; Alice Tomanin; Paolo Peerani; David L. Chichester; Sara A. Pozzi

    2012-10-01

    At nuclear facilities, domestically and internationally, most measurement systems used for nuclear materials’ control and accountability rely on He-3 detectors. Due to resource shortages, alternatives to He-3 systems are needed. This paper presents preliminary simulation and experimental efforts to develop a fast-neutron-multiplicity counter based on liquid organic scintillators. This mission also provides the opportunity to broaden the capabilities of such safeguards measurement systems to improve current neutron-multiplicity techniques and expand the scope to encompass advanced nuclear fuels.

  15. C+C Fusion Cross Sections Measurements for Nuclear Astrophysics

    DOE PAGESBeta

    Almaraz-Calderon, S.; Carnelli, P. F. F.; Rehm, K. E.; Albers, M.; Alcorta, M.; Bertone, P. F.; Digiovine, B.; Esbensen, H.; Fernandez Niello, J. O.; Henderson, D.; et al

    2015-06-02

    Total fusion cross section of carbon isotopes were obtained using the newly developed MUSIC detector. MUSIC is a highly efficient, active target-detector system designed to measure fusion excitation functions with radioactive beams. The present measurements are relevant for understanding x-ray superbursts. The results of the first MUSIC campaign as well as the astrophysical implications are presented in this work.

  16. C+C Fusion Cross Sections Measurements for Nuclear Astrophysics

    NASA Astrophysics Data System (ADS)

    Almaraz-Calderon, S.; Carnelli, P. F. F.; Rehm, K. E.; Albers, M.; Alcorta, M.; Bertone, P. F.; Digiovine, B.; Esbensen, H.; Fernandez Niello, J. O.; Henderson, D.; Jiang, C. L.; Lai, J.; Marley, S. T.; Nusair, O.; Palchan-Hazan, T.; Pardo, R. C.; Paul, M.; Ugalde, C.

    2015-06-01

    Total fusion cross section of carbon isotopes were obtained using the newly developed MUSIC detector. MUSIC is a highly efficient, active target-detector system designed to measure fusion excitation functions with radioactive beams. The present measurements are relevant for understanding x-ray superbursts. The results of the first MUSIC campaign as well as the astrophysical implications are presented in this work.

  17. Studies of the g factors of the ground 4A2 and the first excited 2E state of Cr 3+ ions in emerald

    NASA Astrophysics Data System (ADS)

    Wei, Qun; Guo, Li-Xin; Yang, Zi-Yuan; Wei, Bing

    2011-09-01

    By using complete diagonalization method, the zero-field splitting and g factors of the ground 4A2 and the first excited 2E states of Cr 3+ ions in emerald are calculated. The theoretical results are in good agreement with the experimental data. The dependencies of the g factors on the crystal field parameters, including Dq, v, and v', have been studied. It is shown that, the g factors of the ground state varied with the crystal field parameters approximately in a linear way, but the g factors of the first excited state varied nonlinearly with these parameters.

  18. g-Factors of Isomeric States in the Neutron-Rich Nuclei

    SciTech Connect

    Georgiev, G.; Neyens, G.; Hass, M.; Balabanski, Dimiter Loukanov; Bingham, Carrol R; Borcea, C.; Coulier, N.; Coussenment, R.; Daugas, J. M.; De France, Gilles M; Gorska, M.; Grawe, Hubert H; Grzywacz, Robert Kazimierz; Lewitowicz, Marek; Mach, Henryk A; Matea, I.; de Oliveira Santos, F.; Page, R. D.; Pfutzner, Marek; Penionzhkevich, Yu. E.; Podolyak, Zsolt F; Regan, Patrick H; Rykaczewski, Krzysztof Piotr; Sawicka, M.; Smirnova, N. A.; Sobolev, Yu.; Stanoiu, M.; Teughels, S.; Vyvey, K.

    2004-02-01

    We report the results from the first experiment to measure gyromagnetic factors of {micro}s isomers in neutron-rich nuclei produced by intermediate-energy projectile-fragmentation reactions. The Time Dependent Perturbed Angular Distribution (TDPAD) method was applied in combination with the heavy-ion-gamma correlation technique. The nuclides in the vicinity of {sup 68}Ni were produced and spin-oriented following the fragmentation of a {sup 76}Ge, 61.4 MeV/ u beam at GANIL. The results obtained, |g|({sup 69 m}Cu) = 0.225(25) and |g|({sup 67 m}Ni) = 0.125(6) provide another indication of the importance of proton excitation across the Z = 28 shell gap for the description of these states.

  19. Very high temperature measurements: Application to nuclear reactor safety tests

    NASA Astrophysics Data System (ADS)

    Parga, Clemente Jose

    This PhD dissertation focuses on the improvement of very high temperature thermometry (1100ºC to 2480ºC), with special emphasis on the application to the field of nuclear reactor safety and severe accident research. Two main projects were undertaken to achieve this objective: -The development, testing and transposition of high-temperature fixed point (HTFP) metal-carbon eutectic cells, from metrology laboratory precision (+/-0.001ºC) to applied research with a reasonable degradation of uncertainties (+/-3-5ºC). -The corrosion study and metallurgical characterization of Type-C thermocouple (service temp. 2300ºC) prospective sheath material was undertaken to extend the survivability of TCs used for molten metallic/oxide corium thermometry (below 2000ºC).

  20. USCEA/NIST measurement assurance programs for the radiopharmaceutical and nuclear power industries

    SciTech Connect

    Golas, D.B.

    1993-12-31

    In cooperation with the U.S. Council for Energy Awareness (USCEA), the National Institute of Standards and Technology (NIST) supervises and administers two measurement assurance programs for radioactivity measurement traceability. One, in existence since the mid 1970s, provides traceability to suppliers of radiochemicals and radiopharmaceuticals, dose calibrators, and nuclear pharmacy services. The second program, begun in 1987, provides traceability to the nuclear power industry for utilities, source suppliers, and service laboratories. Each program is described, and the results of measurements of samples of known, but undisclosed activity, prepared at NIST and measured by the participants are presented.

  1. Neutron measurements in Spanish nuclear power plants with a Bonner sphere spectrometer system.

    PubMed

    Fernández, F; Domingo, C; Amgarou, K; Bouassoule, T; García, M J

    2007-01-01

    Neutron spectrometric measurements with an active Bonner Sphere System (BSS) allowed us to determine the reference dosimeter values in Ascó I and II and Cofrentes (PWR, BWR) Spanish nuclear power plants. Under a request from the Spanish National Nuclear Safety Council, the UAB group was in charge of characterising the neutron fields at several measurement points (a total of 10) inside the containment building of these nuclear installations using an active BSS and a home-made MITOM unfolding code. The measurement results in the three installations confirm the presence of low-energy neutron components in almost all selected points. This developed BSS can be considered as a reference system in neutron radiation protection when defining the corresponding protocols for a correct personal dosimetry in nuclear power plant installations. PMID:17525063

  2. Magnetoresistivity and acoustoelectronic effects in a tilted magnetic field in p-Si/SiGe/Si structures with an anisotropic g factor

    SciTech Connect

    Drichko, I. L. Smirnov, I. Yu.; Suslov, A. V.; Mironov, O. A.; Leadley, D. R.

    2010-09-15

    Magnetoresistivity {rho}{sub xx} and {rho}{sub xy} and the acoustoelectronic effects are measured in p-Si/SiGe/Si with an impurity concentration p = 1.99 x 10{sup 11} cm{sup -2} in the temperature range 0.3-2.0 K and an tilted magnetic field up to 18 T. The dependence of the effective g factor on the angle of magnetic field tilt {theta} to the normal to the plane of a two-dimensional p-Si/SiGe/Si channel is determined. A first-order ferromagnet-paramagnet phase transition is observed in the magnetic fields corresponding to a filling factor {nu} = 2 at {theta} {approx} 59{sup o}-60{sup o}.

  3. Assessment of Nuclear Fuels using Radiographic Thickness Measurement Method

    SciTech Connect

    Muhammad Abir; Fahima Islam; Hyoung Koo Lee; Daniel Wachs

    2014-11-01

    The Convert branch of the National Nuclear Security Administration (NNSA) Global Threat Reduction Initiative (GTRI) focuses on the development of high uranium density fuels for research and test reactors for nonproliferation. This fuel is aimed to convert low density high enriched uranium (HEU) based fuel to high density low enriched uranium (LEU) based fuel for high performance research reactors (HPRR). There are five U.S. reactors that fall under the HPRR category, including: the Massachusetts Institute of Technology Reactor (MITR), the National Bureau of Standards Reactor (NBSR), the Missouri University Research Reactor (UMRR), the Advanced Test Reactor (ATR), and the High Flux Isotope Reactor (HFIR). U-Mo alloy fuel phase in the form of either monolithic or dispersion foil type fuels, such as ATR Full-size In center flux trap Position (AFIP) and Reduced Enrichment for Research and Test Reactor (RERTR), are being designed for this purpose. The fabrication process1 of RERTR is susceptible to introducing a variety of fuel defects. A dependable quality control method is required during fabrication of RERTR miniplates to maintain the allowable design tolerances, therefore evaluating and analytically verifying the fabricated miniplates for maintaining quality standards as well as safety. The purpose of this work is to analyze the thickness of the fabricated RERTR-12 miniplates using non-destructive technique to meet the fuel plate specification for RERTR fuel to be used in the ATR.

  4. Theoretical investigations of EPR g factors for Ce3+ ion at monoclinic Cs site in YAlO3 crystal

    NASA Astrophysics Data System (ADS)

    Liu, Hong-Gang; Zheng, Wen-Chen

    2015-01-01

    Three EPR principal g values (gx, gy and gz) for monoclinic (Cs) Ce3+ center in YAlO3 crystal are calculated by the complete diagonalization (of energy matrix) method (CDM) based on the superposition model (SPM) analysis. The calculated g factors are more reasonably closer to experimental results reported by Asatryan et al. (2002) than their same work in 1997. The reliability of fitted crystal-field parameters of YAP:Ce3+ crystal is also analyzed. In SPM calculations, the seeming abnormal negative power-law exponent t6 is found to be actually reasonable and its underlying cause may be explained by future ab initio studies.

  5. Uncertainty minimization in NMR measurements of dynamic nuclear polarization of a proton target for nuclear physics experiments

    SciTech Connect

    Keller, Dustin M.

    2013-11-01

    A comprehensive investigation into the measurement uncertainty in polarization produced by Dynamic Nuclear Polarization is outlined. The polarization data taken during Jefferson Lab experiment E08-007 is used to obtain error estimates and to develop an algorithm to minimize uncertainty of the measurement of polarization in irradiated View the ^14NH_3 targets, which is readily applied to other materials. The target polarization and corresponding uncertainties for E08-007 are reported. The resulting relative uncertainty found in the target polarization is determined to be less than or equal to 3.9%.

  6. Implementation of an Enhanced Measurement Control Program for handling nuclear safety samples at WSRC

    SciTech Connect

    Boler-Melton, C.; Holland, M.K.

    1991-01-01

    In the separation and purification of nuclear material, nuclear criticality safety (NCS) is of primary concern. The primary nuclear criticality safety controls utilized by the Savannah River Site (SRS) Separations Facilities involve administrative and process equipment controls. Additional assurance of NCS is obtained by identifying key process hold points where sampling is used to independently verify the effectiveness of production control. Nuclear safety measurements of samples from these key process locations provide a high degree of assurance that processing conditions are within administrative and procedural nuclear safety controls. An enhanced procedure management system aimed at making improvements in the quality, safety, and conduct of operation was implemented for Nuclear Safety Sample (NSS) receipt, analysis, and reporting. All procedures with nuclear safety implications were reviewed for accuracy and adequate detail to perform the analytical measurements safely, efficiently, and with the utmost quality. Laboratory personnel worked in a Deliberate Operating'' mode (a systematic process requiring continuous expert oversight during all phases of training, testing, and implementation) to initiate the upgrades. Thus, the effort to revise and review nuclear safety sample procedures involved a team comprised of a supervisor, chemist, and two technicians for each procedure. Each NSS procedure was upgraded to a Use Every Time'' (UET) procedure with sign-off steps to ensure compliance with each step for every nuclear safety sample analyzed. The upgrade program met and exceeded both the long and short term customer needs by improving measurement reliability, providing objective evidence of rigid adherence to program principles and requirements, and enhancing the system for independent verification of representative sampling from designated NCS points.

  7. Implementation of an Enhanced Measurement Control Program for handling nuclear safety samples at WSRC

    SciTech Connect

    Boler-Melton, C.; Holland, M.K.

    1991-12-31

    In the separation and purification of nuclear material, nuclear criticality safety (NCS) is of primary concern. The primary nuclear criticality safety controls utilized by the Savannah River Site (SRS) Separations Facilities involve administrative and process equipment controls. Additional assurance of NCS is obtained by identifying key process hold points where sampling is used to independently verify the effectiveness of production control. Nuclear safety measurements of samples from these key process locations provide a high degree of assurance that processing conditions are within administrative and procedural nuclear safety controls. An enhanced procedure management system aimed at making improvements in the quality, safety, and conduct of operation was implemented for Nuclear Safety Sample (NSS) receipt, analysis, and reporting. All procedures with nuclear safety implications were reviewed for accuracy and adequate detail to perform the analytical measurements safely, efficiently, and with the utmost quality. Laboratory personnel worked in a ``Deliberate Operating`` mode (a systematic process requiring continuous expert oversight during all phases of training, testing, and implementation) to initiate the upgrades. Thus, the effort to revise and review nuclear safety sample procedures involved a team comprised of a supervisor, chemist, and two technicians for each procedure. Each NSS procedure was upgraded to a ``Use Every Time`` (UET) procedure with sign-off steps to ensure compliance with each step for every nuclear safety sample analyzed. The upgrade program met and exceeded both the long and short term customer needs by improving measurement reliability, providing objective evidence of rigid adherence to program principles and requirements, and enhancing the system for independent verification of representative sampling from designated NCS points.

  8. Lead Slowing Down Spectrometry Analysis of Data from Measurements on Nuclear Fuel

    SciTech Connect

    Warren, Glen A.; Anderson, Kevin K.; Kulisek, Jonathan A.; Danon, Yaron; Weltz, Adam; Gavron, Victor A.; Harris, Jason; Stewart, Trevor N.

    2015-01-12

    Improved non-destructive assay of isotopic masses in used nuclear fuel would be valuable for nuclear safeguards operations associated with the transport, storage and reprocessing of used nuclear fuel. Our collaboration is examining the feasibility of using lead slowing down spectrometry techniques to assay the isotopic fissile masses in used nuclear fuel assemblies. We present the application of our analysis algorithms on measurements conducted with a lead spectrometer. The measurements involved a single fresh fuel pin and discrete 239Pu and 235U samples. We are able to describe the isotopic fissile masses with root mean square errors over seven different configurations to 6.35% for 239Pu and 2.7% for 235U over seven different configurations. Funding Source(s):

  9. Measurement of Nuclear Transparency for the A(e,e' pi^+) Reaction

    SciTech Connect

    B. Clasie; X. Qian; J. Arrington; R. Asaturyan; F. Benmokhtar; W. Boeglin; P. Bosted; A. Bruell; M. E. Christy; E. Chudakov; W. Cosyn; M. M. Dalton; A. Daniel; D. Day; D. Dutta; L. El Fassi; R. Ent; H. C. Fenker; J. Ferrer; N. Fomin; H. Gao; K. Garrow; D. Gaskell; C. Gray; T. Horn; G. M. Huber; M. K. Jones; N. Kalantarians; C. E. Keppel; K. Kramer; A. Larson; Y. Li; Y. Liang; A. F. Lung; S. Malace; P. Markowitz; A. Matsumura; D. G. Meekins; T. Mertens; G. A. Miller; T. Miyoshi; H. Mkrtchyan; R. Monson; T. Navasardyan; G. Niculescu; I. Niculescu; Y. Okayasu; A. K. Opper; C. Perdrisat; V. Punjabi; A. W. Rauf; V. M. Rodriquez; D. Rohe; J. Ryckebusch; J. Seely; E. Segbefia; G. R. Smith; M. Strikman; M. Sumihama; V. Tadevosyan; L. Tang; V. Tvaskis; A. Villano; W. F. Vulcan; F. R. Wesselmann; S. A. Wood; L. Yuan; X. C. Zheng

    2007-12-01

    We have measured the nuclear transparency of the A(e,e' pi^+) process in ^{2}H,^{12}C, ^{27}Al, ^{63}Cu and ^{197}Au targets. These measurements were performed at the Jefferson Laboratory over a four momentum transfer squared range Q^2 = 1.1 - 4.7 (GeV/c)^2. The nuclear transparency was extracted as the super-ratio of $(\\sigma_A/\\sigma_H)$ from data to a model of pion-electroproduction from nuclei without pi-N final state interactions. The Q^2 and atomic number dependence of the nuclear transparency both show deviations from traditional nuclear physics expectations, and are consistent with calculations that include the quantum chromodynamical phenomenon of color transparency.

  10. Studies of shock convergence in ICF implosions using nuclear burn history measurements

    NASA Astrophysics Data System (ADS)

    Rygg, J. R.; Delettrez, J. A.

    2005-10-01

    Ignition of ICF capsules on the NIF will be critically dependent on the quality of hot-spot heating due to converging shock waves. On OMEGA, the convergence of strong spherical shocks heats the inner gas sufficiently to induce nuclear fusion. Measurements of the time history of this nuclear burn show that the burn induced by shock convergence occurs several hundred picoseconds before the deceleration-phase compression burn. The nuclear burn history measurements of two distinct nuclear reactions will be compared to a Guderley self-similar imploding shock analysis, as well as to 1-D hydrodynamic simulations. This work was supported in part by LLE, LLNL, the U.S. DoE, the Univ. of Rochester, and the N.Y.State Energy Research and Development Authority.

  11. Calorimeter measures high nuclear heating rates and their gradients across a reactor test hole

    NASA Technical Reports Server (NTRS)

    Burwell, D.; Coombe, J. R.; Mc Bride, J.

    1970-01-01

    Pedestal-type calorimeter measures gamma-ray heating rates from 0.5 to 7.0 watts per gram of aluminum. Nuclear heating rate is a function of cylinder temperature change, measured by four chromel-alumel thermocouples attached to the calorimeter, and known thermoconductivity of the tested material.

  12. Measurement of Charged Pions from Neutrino-produced Nuclear Resonance

    SciTech Connect

    Simon, Clifford N.

    2014-01-01

    A method for identifying stopped pions in a high-resolution scintillator bar detector is presented. I apply my technique to measure the axial mass MΔAfor production of the Δ(1232) resonance by neutrino, with the result MΔA = 1.16±0.20 GeV (68% CL) (limited by statistics). The result is produced from the measured spectrum of reconstructed momentum-transfer Q2. I proceed by varying the value of MΔA in a Rein-Sehgal-based Monte Carlo to produce the best agreement, using shape only (not normalization). The consistency of this result with recent reanalyses of previous bubble-chamber experiments is discussed.

  13. Recent Nuclear Astrophysics Measurements using the TwinSol Separator

    NASA Astrophysics Data System (ADS)

    Bardayan, D. W.; Ahn, T.; Allen, J.; Becchetti, F. D.; Blackmon, J. C.; Brodeur, M.; Frentz, B.; Gupta, Y. K.; Hall, M. R.; Hall, O.; Henderson, S.; Hu, J.; Kelly, J. M.; Kolata, J. J.; Long, A.; Long, J.; Macon, K.; Nicoloff, C.; O'Malley, P. D.; Ostdiek, K.; Pain, S. D.; Riggins, J.; Schultz, B. E.; Smith, M.; Strauss, S.; Torres-Isea, R. O.

    2016-07-01

    Many astrophysical events, such as novae and X-ray bursts, are powered by reactions with radioactive nuclei. Studying the properties of these nuclei in the laboratory can therefore further our understanding of these astrophysical explosions. The TwinSol separator at the University of Notre Dame has recently been used to produce intense (∼106 pps) beams of 17F. In this article, some of the first measurements with these beams are discussed.

  14. Iodine magnetic moments measured by on-line nuclear orientation

    NASA Astrophysics Data System (ADS)

    Stone, N. J.; Rikovska, J.; Green, V. R.; Shaw, T. L.; Krane, K. S.; Walker, P. M.; Grant, I. S.

    1987-03-01

    On-Line measurements of magnetic dipole moments of117 122I are interpreted using coupling of the odd particles to a deformed core. The results show interesting effects of g7/2, d5/2 orbital admixtures in the odd-A isotopes, which are close to spherical. The odd-odd isotopes118, 120I show clear examples of shape co-existence.

  15. Spreadsheet analysis of gamma spectra for nuclear material measurements

    SciTech Connect

    Mosby, W.R.; Pace, D.M.

    1990-01-01

    A widely available commercial spreadsheet package for personal computers is used to calculate gamma spectra peak areas using both region of interest and peak fitting methods. The gamma peak areas obtained are used for uranium enrichment assays and for isotopic analyses of mixtures of transuranics. The use of spreadsheet software with an internal processing language allows automation of routine analysis procedures increasing ease of use and reducing processing errors while providing great flexibility in addressing unusual measurement problems. 4 refs., 9 figs.

  16. Cross section measurements via residual nuclear decays: Analysis methods

    SciTech Connect

    Zhou Fengqun; Gao Lei; Li Kuohu; Song Yueli; Zhang Fang; Kong Xiangzhong; Luo Junhua

    2009-11-15

    We develop an approach to calculating the pure cross section of the ground state of artificial radioactive nuclides that subtracts the effect of an excited state on the ground state. We apply a formalism to obtaining pure cross sections by subtracting the effect of excited states in the reactions {sup 122}Te(n,2n){sup 121}Te{sup g} and {sup 128}Te(n,2n){sup 127}Te{sup g}, induced by neutrons of about 14 MeV. The cross sections are measured by an activation relative to the {sup 93}Nb(n,2n){sup 92}Nb{sup m} reaction and are compared with results that take into account the effect of the excited state. Measurements are carried out by {gamma} detection using a coaxial high-purity germanium (HPGe) detector. As samples, spectroscopically pure Te powder is used. The fast neutrons are produced by the {sup 3}H(d,n){sup 4}He reaction. The neutron energies in these measurements are determined using the method of cross-section ratios between the {sup 90}Zr(n,2n){sup 89}Zr{sup m+g} and {sup 93}Nb(n,2n){sup 92}Nb{sup m} reactions.

  17. Optical pump-probe measurements of local nuclear spin coherence in semiconductor quantum wells.

    PubMed

    Sanada, H; Kondo, Y; Matsuzaka, S; Morita, K; Hu, C Y; Ohno, Y; Ohno, H

    2006-02-17

    We demonstrate local manipulation and detection of nuclear spin coherence in semiconductor quantum wells by an optical pump-probe technique combined with pulse rf NMR. The Larmor precession of photoexcited electron spins is monitored by time-resolved Kerr rotation (TRKR) as a measure of nuclear magnetic field. Under the irradiation of resonant pulsed rf magnetic fields, Rabi oscillations of nuclear spins are traced by TRKR signals. The intrinsic coherence time evaluated by a spin-echo technique reveals the dependence on the orientation of the magnetic field with respect to the crystalline axis as expected by the nearest neighbor dipole-dipole interaction. PMID:16606048

  18. Measuring of fissile isotope partial antineutrino spectra in direct experiment at nuclear reactor

    SciTech Connect

    Sinev, V. V.

    2009-11-15

    The direct measuring method is considered to get nuclear reactor antineutrino spectrum. We suppose to isolate partial spectra of the fissile isotopes by using the method of antineutrino spectrum extraction from the inverse beta-decay reaction positron spectrum applied at Rovno experiment. This admits to increase the accuracy of partial antineutrino spectra forming the total nuclear reactor spectrum. It is important for the analysis of the reactor core fuel composition and could be applied for non-proliferation purposes.

  19. g -factors of conduction electrons and holes in B i2S e3 three-dimensional topological insulator

    NASA Astrophysics Data System (ADS)

    Wolos, A.; Szyszko, S.; Drabinska, A.; Kaminska, M.; Strzelecka, S. G.; Hruban, A.; Materna, A.; Piersa, M.; Borysiuk, J.; Sobczak, K.; Konczykowski, M.

    2016-04-01

    Bulk-related conduction electron spin resonance and conduction hole spin resonance were investigated in B i2S e3 , a three-dimensional topological insulator. Electrons in the conduction band and holes in the valence band both have spin ½. The effective g -factors for conduction electrons are equal to 27.3 ± 0.15 for magnetic field parallel to the c axis and 19.48 ± 0.07 for magnetic field perpendicular to the c axis, whereas for conduction holes 29.90 ± 0.09 for magnetic field parallel and 18.96 ± 0.04 for magnetic field perpendicular to the c axis, respectively. Nonparabolicity effects were not observed in the investigated low carrier concentration range, below 8 ×1017c m-3 . Large g -factors, higher by an order of magnitude than the free electron value, are due to strong spin-orbit interactions in B i2S e3 . The striking similarity of the spin resonances due to conduction electrons and holes confirms the peculiar symmetry between the conduction and valence bands of B i2S e3 , both having similar effective masses and spin character.

  20. A pair spectrometer for measuring multipolarities of energetic nuclear transitions

    NASA Astrophysics Data System (ADS)

    Gulyás, J.; Ketel, T. J.; Krasznahorkay, A. J.; Csatlós, M.; Csige, L.; Gácsi, Z.; Hunyadi, M.; Krasznahorkay, A.; Vitéz, A.; Tornyi, T. G.

    2016-02-01

    An electron-positron pair spectrometer has been designed and constructed for the simultaneous measurement of energy- and angular correlations of e+e- pairs. Experimental results are obtained over a wide angular range for high-energy transitions in 16O, 12C and 8Be. The results showed that the angular correlations between 50 and 180° of the e+e- pairs in the energy range between 6 and 18 MeV can be determined with sufficient resolution and efficiency in good agreement with the GEANT simulations.

  1. Correlation measurements in nuclear {beta}-decay using traps and polarized low energy beams

    SciTech Connect

    Naviliat-Cuncic, Oscar

    2013-05-06

    Precision measurements in nuclear {beta}-decay provide sensitive means to test discrete symmetries in the weak interaction and to determine some of the fundamental constants in semi-leptonic decays, like the coupling of the lightest quarks to charged weak bosons. The main motivation of such measurements is to find deviations from Standard Model predictions as possible indications of new physics. In this contribution I will focus on two topics related to precision measurements in nuclear {beta}-decay: i) the determination of the V{sub ud} element of the Cabibbo-Kobayashi-Maskawa quark mixing matrix from nuclear mirror transitions and ii) the search for exotic scalar or tensor contributions from {beta}{nu} angular correlations. The purpose is to underline the role being played by experimental techniques based on the confinement of radioactive species with atom and ion traps as well as the plans to use low energy polarized beams.

  2. First measurement of the ionization yield of nuclear recoils in liquid argon

    SciTech Connect

    Joshi, T.; Sangiorgio, Samuele; Bernstein, A.; Foxe, Michael P.; Hagmann, Chris; Jovanovic, Igor; Kazkaz, K.; Mozin, Vladimir V.; Norman, E. B.; Pereverzev, S. V.; Rebassoo, Finn O.; Sorensen, Peter F.

    2014-05-01

    Liquid phase argon has long been used as a target medium for particle detection via scintillation light. Recently there has been considerable interest in direct detection of both hypothetical darkmatter particles and coherent elastic neutrino nucleus scattering. These as-yet unobserved neutral particle interactions are expected to result in a recoiling argon atom O(keV), generally referred to in the literature as a nuclear recoil. This prompts the question of the available electromagnetic signal in a liquid argon detector. In this Letter we report the first measurement of the ionization yield (Qy), detected electrons per unit energy, resulting from nuclear recoils in liquid argon, measured at 6.7 keV. This is also the lowest energy measurement of nuclear recoils in liquid argon.

  3. Estimation of measurement accuracy of track point coordinates in nuclear photoemulsion

    NASA Astrophysics Data System (ADS)

    Shamanov, V. V.

    1995-03-01

    A simple method for an estimation of the measurement accuracy of track point coordinates in nuclear photoemulsion is described. The method is based on analysis of residual deviations of measured track points from a straight line approximating the track. Reliability of the algorithm is illustrated by Monte Carlo simulation. Examples of using the method for an estimation of the accuracy of track point coordinates measured with the microscope KSM-1 (VEB Carl Zeiss Jena) are given.

  4. Plutonium Measurements with a Fast-Neutron Multiplicity Counter for Nuclear Safeguards Applications

    SciTech Connect

    Jennifer L. Dolan; Marek Flaska; Alexis Poitrasson-Riviere; Andreas Enqvist; Paolo Peerani; David L. Chichester; Sara A. Pozzi

    2014-11-01

    Measurements were performed at the Joint Research Centre in Ispra, Italy to field test a fast-neutron multiplicity counter developed at the University of Michigan. The measurements allowed the illustration of the system’s photon discrimination abilities, efficiency when measuring neutron multiplicity, ability to characterize 240Pueff mass, and performance relative to a currently deployed neutron coincidence counter. This work is motivated by the need to replace and improve upon 3He neutron detection systems for nuclear safeguards applications.

  5. Plutonium measurements with a fast-neutron multiplicity counter for nuclear safeguards applications

    NASA Astrophysics Data System (ADS)

    Dolan, Jennifer L.; Flaska, Marek; Poitrasson-Riviere, Alexis; Enqvist, Andreas; Peerani, Paolo; Chichester, David L.; Pozzi, Sara A.

    2014-11-01

    Measurements were performed at the Joint Research Centre in Ispra, Italy to field test a fast-neutron multiplicity counter developed at the University of Michigan. The measurements allowed the assessment of the system's photon discrimination abilities, efficiency when measuring neutron multiplicity, ability to characterize 240Pueff mass, and performance relative to a currently deployed neutron coincidence counter. This work is motivated by the need to replace and improve upon 3He neutron detection systems for nuclear safeguards applications.

  6. Anisotropic electron g factor as a probe of the electronic structure of GaBixAs1 -x/GaAs epilayers

    NASA Astrophysics Data System (ADS)

    Broderick, Christopher A.; Mazzucato, Simone; Carrère, Hélène; Amand, Thierry; Makhloufi, Hejer; Arnoult, Alexandre; Fontaine, Chantal; Donmez, Omer; Erol, Ayşe; Usman, Muhammad; O'Reilly, Eoin P.; Marie, Xavier

    2014-11-01

    The electron Landé g factor (g*) is investigated both experimentally and theoretically in a series of GaBixAs1 -x /GaAs strained epitaxial layers, for bismuth compositions up to x =3.8 % . We measure g* via time-resolved photoluminescence spectroscopy, which we use to analyze the spin quantum beats in the polarization of the photoluminescence in the presence of an externally applied magnetic field. The experimental measurements are compared directly to atomistic tight-binding calculations on large supercells, which allows us to explicitly account for alloy disorder effects. We demonstrate that the magnitude of g* increases strongly with increasing Bi composition x and, based on the agreement between the theoretical calculations and experimental measurements, elucidate the underlying causes of the observed variation of g*. By performing measurements in which the orientation of the applied magnetic field is changed, we further demonstrate that g* is strongly anisotropic. We quantify the observed variation of g* with x , and its anisotropy, in terms of a combination of epitaxial strain and Bi-induced hybridization of valence states due to alloy disorder, which strongly perturbs the electronic structure.

  7. Recent Fast Neutron Imaging Measurements with the Fieldable Nuclear Materials Identification System

    SciTech Connect

    Mullens, James Allen; Mihalczo, John T; Archer, Daniel E; Thompson, Thad; Britton Jr, Charles L; Ezell, N Dianne Bull; Ericson, Milton Nance; Farquhar, Ethan; Lind, Randall F; Carter, Jake

    2015-01-01

    This paper describes some recent fast neutron imaging measurements of the fieldable nuclear materials identification system (FNMIS) under development by the National Nuclear Security Administration (NNSA-NA-22) for possible future use in arms control and nonproliferation applications. The general configuration of FNMIS has been previously described, and a description of the application-specific integrated circuit (ASIC) electronics designed for FNMIS has been reported. This paper presents initial imaging measurements performed at ORNL with a Thermo Fisher API 120 DT generator and the fast-neutron imaging module of FNMIS.

  8. Measurement method for the nuclear anapole moment of laser-trapped alkali-metal atoms

    SciTech Connect

    Gomez, E.; Aubin, S.; Sprouse, G. D.; Orozco, L. A.; DeMille, D. P.

    2007-03-15

    Weak interactions within a nucleus generate a nuclear spin dependent, parity-violating electromagnetic moment, the anapole moment. We analyze a method to measure the nuclear anapole moment through the electric dipole transition it induces between hyperfine states of the ground level. The method requires tight confinement of the atoms to position them at the antinode of a standing wave Fabry-Perot cavity driving the anapole-induced microwave E1 transition. We explore the necessary limits in the number of atoms, excitation fields, trap type, interrogation method, and systematic tests necessary for such measurements in francium, the heaviest alkali.

  9. Measurement of the nuclear polarization of hydrogen and deuterium molecules using a Lamb-shift polarimeter

    SciTech Connect

    Engels, Ralf Gorski, Robert; Grigoryev, Kiril; Mikirtychyants, Maxim; Rathmann, Frank; Seyfarth, Hellmut; Ströher, Hans; Weiss, Philipp; Kochenda, Leonid; Kravtsov, Peter; Trofimov, Viktor; Tschernov, Nikolay; Vasilyev, Alexander; Vznuzdaev, Marat; Schieck, Hans Paetz gen.

    2014-10-15

    Lamb-shift polarimeters are used to measure the nuclear polarization of protons and deuterons at energies of a few keV. In combination with an ionizer, the polarization of hydrogen and deuterium atoms was determined after taking into account the loss of polarization during the ionization process. The present work shows that the nuclear polarization of hydrogen or deuterium molecules can be measured as well, by ionizing the molecules and injecting the H{sub 2}{sup +} (or D{sub 2}{sup +}) ions into the Lamb-shift polarimeter.

  10. Two Phase Flow Measurements by Nuclear Magnetic Resonance (NMR)

    SciTech Connect

    Altobelli, Stephen A; Fukushima, Eiichi

    2006-08-14

    In concentrated suspensions, there is a tendency for the solid phase to migrate from regions of high shear rate to regions of low shear (Leighton & Acrivos, 1987). In the early years that our effort was funded by the DOE Division of Basic Energy Science, quantitative measurement of this process in neutrally buoyant suspensions was a major focus (Abbott, et al., 1991; Altobelli, et al., 1991). Much of this work was used to improve multi-phase numerical models at Sandia National Laboratories. Later, our collaborators at Sandia and the University of New Mexico incorporated body forces into their numerical models of suspension flow (Rao, Mondy, Sun, et al., 2002). We developed experiments that allow us to study flows driven by buoyancy, to characterize these flows in well-known and useful engineering terms (Altobelli and Mondy, 2002) and to begin to explore the less well-understood area of flows with multiple solid phases (Beyea, Altobelli, et al., 2003). We also studied flows that combine the effects of shear and buoyancy, and flows of suspensions made from non-Newtonian liquids (Rao, Mondy, Baer, et al, 2002). We were able to demonstrate the usefulness of proton NMR imaging of liquid phase concentration and velocity and produced quantitative data not obtainable by other methods. Fluids flowing through porous solids are important in geophysics and in chemical processing. NMR techniques have been widely used to study liquid flow in porous media. We pioneered the extension of these studies to gas flows (Koptyug, et al, 2000, 2000, 2001, 2002). This extension allows us to investigate a wider range of Peclet numbers, and to gather data on problems of interest in catalysis. We devised two kinds of NMR experiments for three-phase systems. Both experiments employ two NMR visible phases and one phase that gives no NMR signal. The earlier method depends on the two visible phases differing in a NMR relaxation property. The second method (Beyea, Altobelli, et al., 2003) uses two

  11. Density measurements of road overlays samples with nuclear gauges and a Step Frequency Radar

    NASA Astrophysics Data System (ADS)

    Fauchard, C.; Li, B.; Kadi, M.

    2012-04-01

    The density of Hot-Mix Asphalt layers (HMA) and thin overlays is an important parameter for the pavement quality and its long time performance. In the laboratory, the density could be measured with nuclear gauges based on the gamma rays absorption through cores samples drilled from the pavement. However, it is a destructive testing. For in-place control, the density could be measured with nuclear gauges based on the back-scattered gamma rays. But it is limited to overlays thickness greater than 3 cm. For both cases, nuclear gauges require specific training and certification for users. The use of a nuclear source (generally Cesium 137) is a major constraint for transportation and is a threat for operator safety. This work proposes a laboratory density measurement with an electromagnetic method, the Step Frequency Radar developped in our institute (Fauchard et al, 2009). It is based on the same physical principle than the Ground Penetrating Radar, but the used frequencies allow the study of very thin asphalt overlays less than 3 cm and the possible non-destructive measurement of in-place density with high performance. For this study, the dimensions of the device are designed to measure the density of slab samples (40*60*8 cm) in laboratory. The results are compared to the nuclear density measurement used in French Labs. Three kinds of slabs are implemented with four various degrees of compaction (88, 90, 92 and 94%) according to the French norm. Their composition is known and differs mainly with the nature of the aggregates (basalt, quartzite and limestone) that represent the main part of the mix materials. Then the permittivity of the samples is measured according to the reflected waves on surface and bottom slabs. A Complex Refractive Index Model gives the measured permittivity of the tested mix as a function of the compaction and the content, permittiviy and density of each component (filler, aggregates and bitumen). The obtained density is very closed to the

  12. Electron g-factor in bulk Ga1-xInxAsySb1-y/GaSb quaternary alloy and in GaSb/Ga1-xInxAsySb1-y/GaSb Spherical quantum dots

    NASA Astrophysics Data System (ADS)

    Sánchez-Cano, R.; Porras-Montenegro, N.

    2011-12-01

    Secure quantum communications require an entanglement-preserving photo-detector in which quantum information is transmitted by photon polarization through an mid infrared optical fiber system and then transferred to electron spin in a optoelectronic semiconductor device. Using interpolation scheme we have investigated the electron g-factor in bulk Ga1-xInxAsySb1-y quaternary alloy matched to GaSb as a function of Indium and Arsenic concentration on the complete range 0≤x,y≤1. A specific g-factor as a function of the radius in a spherical GaSb/Ga1-xInxAsySb1-y/GaSb quantum dot heterostructure is calculated. Furthermore, we present calculations of the energy states including the Zeeman effect on the electrons confined in quaternary heterostructure quantum dots, with a parabolic confining potential under applied magnetic fields. Our calculations have been worked out by using interpolating methods to find the band gap as a function of the Indium concentration in order to determine the conduction band-offset at room temperature in GaSb/Ga1-xInxAsySb1-y/GaSb heterostructure, within the effective-mass approximation. Experimental or theoretical electron g-factor, spin-orbit splitting Δso, and coupling matrix elements Ep = (2/m0)||2 value between the states of the lowest conduction band Γ6 and the upper valence bands Γ8 for Ga1-xInxAsySb1-y/GaSb quaternary alloy are not readily available. Our predictions show that electron g-factor values are in the range between the electron g-factor measured in bulk GaSb when x→0 (g = -9.25) and that measured in InAs when x→1 (g = -18.08), but there is a remarkable minimum in the g-factor value (g≃-23.14) at x≃0.67.

  13. Development, calibration, and experimental results obtained with an innovative calorimeter (CALMOS) for nuclear heating measurements

    SciTech Connect

    Carcreff, Hubert; Cloute-Cazalaa, Veronique; Salmon, Laurent

    2012-08-15

    Nuclear heating inside an MTR reactor has to be known in order to be able to control samples temperature during irradiation experiments. An R and D program has been carried out at CEA to design a new type of in-core calorimetric system. This new development, started in 2002, has for main objective to manufacture a calorimeter suitable to monitoring nuclear heating inside the 70 MWth OSIRIS material testing reactor operated by CEA's Nuclear Energy Division at the Saclay research center. An innovative calorimetric probe, associated to a specific handling system, has been designed to provide access to measurements both along the fissile height and on the upper part of the core, where nuclear heating still remains high. Two mock-ups of the probe were manufactured and tested in 2005 and 2009 in ex-core area of OSIRIS reactor for process validation, while a displacement system has been especially studied to move the probe along a given axial measurement range. This paper deals with the development, tests on preliminary mock-ups and the finalization of the probe. Main modeling and experimental results are presented. Moreover, alternative methods to calibration for nuclear heating rate measurements which are now possible with this new calorimeter are presented and discussed. (authors)

  14. Development, calibration and experimental results obtained with an innovative calorimeter (CALMOS) for nuclear heating measurements

    SciTech Connect

    Carcreff, H.; Cloute-Cazalaa, V.; Salmon, L.

    2011-07-01

    Nuclear heating inside an MTR reactor has to be known in order to be able to control samples temperature during irradiation experiments. An R and D program has been carried out at CEA to design a new type of in-core calorimetric system. This new development, started in 2002, has for main objective to manufacture a calorimeter suitable to monitoring nuclear heating inside the 70 MWth OSIRIS material testing reactor operated by CEA's Nuclear Energy Div. at the Saclay research center. An innovative calorimetric probe, associated to a specific handling system, has been designed to provide access to measurements both along the fissile height and on the upper part of the core, where nuclear heating still remains high. Two mock-ups of the probe were manufactured and tested in 2005 and 2009 in ex-core area of OSIRIS reactor for process validation, while a displacement system has been especially studied to move the probe along a given axial measurement range. This paper deals with the development, tests on preliminary mock-ups and the finalization of the probe. Main modeling and experimental results are presented. Moreover, alternative methods to calibration for nuclear heating rate measurements which are now possible with this new calorimeter are presented and discussed. (authors)

  15. Monte Carlo Simulation Study of a Differential Calorimeter Measuring the Nuclear Heating in Material Testing Reactors

    NASA Astrophysics Data System (ADS)

    Amharrak, H.; Reynard-Carette, C.; Lyoussi, A.; Carette, M.; Brun, J.; De Vita, C.; Fourmentel, D.; Villard, J.-F.; Guimbal, P.

    2016-02-01

    The nuclear heating measurements in Material Testing Reactors (MTRs) are crucial for the study of nuclear materials and fuels under irradiation. The reference measurements of this nuclear heating are especially performed by a differential calorimeter including a graphite sample material. Then these measurements are used for other materials, other geometries, or other experimental conditions in order to predict the nuclear heating and thermal conditions induced in the irradiation devices. This paper will present new simulations with MCNP Monte-Carlo transport code to determine the gamma heating profile inside the calorimeter. The whole complex geometry of the sensor has been considered. We use as an input source in the model, the photon spectra calculated in various positions of CARMEN-1 irradiation program in OSIRIS reactor. After a description of the differential calorimeter device, the MCNP modeling used for the calculations of radial profile of nuclear heating inside the calorimeter elements will be introduced. The obtained results of different simulations will be detailed and discussed in this paper. The charged particle equilibrium inside the calorimeter elements will be studied. Then we will focus on parametric studies of the various components of the calorimeter. The influence of source type will be also took into account. Moreover the influence of the material used for the sample will be described.

  16. Neutron cross section measurements at ORELA for improved nuclear data and their application.

    PubMed

    Guber, K H; Leal, L C; Sayer, R O; Koehler, P E; Valentine, T E; Derrien, H; Harvey, J A

    2005-01-01

    To support the Nuclear Criticality Safety Program, the Oak Ridge Electron Linear Accelerator (ORELA) has been used to measure the total and capture neutron cross sections of several nuclides in the energy range from 100 eV to -600 keV. Concerns about the use of existing cross section data in nuclear criticality calculations have been a prime motivator for the new cross-section measurements. Our new capture cross sections of aluminium, silicon, chlorine, fluorine and potassium in the energy range from 100 eV to 600 keV are substantially different from the cross sections in evaluated nuclear data files of ENDF/B-VI and JENDL-3.2. PMID:16604703

  17. Reactivity worth measurements at the IPEN/MB-01 nuclear reactor

    SciTech Connect

    Pinto, Leticia Negrao; Santos, Adimir dos

    2013-05-06

    Researches that aim to improve the performance of neutron transport codes and quality of nuclear cross section databases are very important to increase the accuracy of simulations and the quality of the analysis and prediction of phenomena in the nuclear field. In this context, relevant experimental data such as reactivity worth measurements are needed. The objective of this work was to perform a series of experiments of reactivity worth measurements, using a digital reactivity meter developed at IPEN. The experiments employed small metallic and ceramic samples inserted in the central region of the core of the experimental IPEN/MB-01 reactor. The theoretical analysis was performed by the MCNP-5 reactor physics code, developed and maintained by Los Alamos National Laboratory, and the ENDF/B-VII.0 nuclear data library.

  18. Can one measure nuclear matrix elements of neutrinoless double {beta} decay?

    SciTech Connect

    Rodin, Vadim; Faessler, Amand

    2009-10-15

    By making use of the isospin conservation by strong interaction, the Fermi 0{nu}{beta}{beta} nuclear matrix element M{sub F}{sup 0{nu}} is transformed to acquire the form of an energy-weighted double Fermi transition matrix element. This useful representation allows reconstruction of the total M{sub F}{sup 0{nu}} provided a small isospin-breaking Fermi matrix element between the isobaric analog state in the intermediate nucleus and the ground state of the daughter nucleus could be measured, e.g., by charge-exchange reactions. Such a measurement could set a scale for the 0{nu}{beta}{beta} nuclear matrix elements and help to discriminate between the different nuclear structure models in which calculated M{sub F}{sup 0{nu}} may differ by as much as a factor of 5 (that translates to about 20% difference in the total M{sup 0{nu}})

  19. Precision measurement of the nuclear polarization in laser-cooled, optically pumped 37K

    NASA Astrophysics Data System (ADS)

    Fenker, B.; Behr, J. A.; Melconian, D.; Anderson, R. M. A.; Anholm, M.; Ashery, D.; Behling, R. S.; Cohen, I.; Craiciu, I.; Donohue, J. M.; Farfan, C.; Friesen, D.; Gorelov, A.; McNeil, J.; Mehlman, M.; Norton, H.; Olchanski, K.; Smale, S.; Thériault, O.; Vantyghem, A. N.; Warner, C. L.

    2016-07-01

    We report a measurement of the nuclear polarization of laser-cooled, optically pumped 37K atoms which will allow us to precisely measure angular correlation parameters in the {β }+-decay of the same atoms. These results will be used to test the V ‑ A framework of the weak interaction at high precision. At the Triumf neutral atom trap (Trinat), a magneto-optical trap confines and cools neutral 37K atoms and optical pumping spin-polarizes them. We monitor the nuclear polarization of the same atoms that are decaying in situ by photoionizing a small fraction of the partially polarized atoms and then use the standard optical Bloch equations to model their population distribution. We obtain an average nuclear polarization of \\bar{P}=0.9913+/- 0.0009, which is significantly more precise than previous measurements with this technique. Since our current measurement of the β-asymmetry has 0.2 % statistical uncertainty, the polarization measurement reported here will not limit its overall uncertainty. This result also demonstrates the capability to measure the polarization to \\lt 0.1 % , allowing for a measurement of angular correlation parameters to this level of precision, which would be competitive in searches for new physics.

  20. Proposal for Drell-Yan Measurements of Nucleon and Nuclear Structure with the FNAL Main Injector

    SciTech Connect

    Isenhower, L.D.; Sadler, M.E.; Arrinton, J.; Geesamn, D.F.; Holt, R.J.; Jackson, H.E.; Reimer, P.E.; Potterveld, D.H.; Brown, C.N.; Garvey, G.T.; Leitch, M.J.; /Los Alamos /Rutgers U. /Texas A-M /Valparaiso U.

    2001-04-01

    We propose measuring the fractional momentum (x) dependence of the ratio of the anti-down to anti-up quark distributions in the proton, {bar d}(x)/{bar u}(x), using proton induced Drell-Yan reactions at 120 GeV. Recent measurements by FNAL E866 unexpectedly show considerable x dependence in this ratio for x > 0.2. A lower energy primary proton beam from the Main Injector makes it possible to extend the E866 measurements to larger x with much higher precision. The apparatus will also be used with nuclear targets to measure parton energy loss and modifications to anti-quark distributions in nuclear targets at large x (x > 0.2).

  1. Insight on the inconsistencies of Barkhausen signal measurements for radiation damage on nuclear reactor steel

    SciTech Connect

    Barroso, Soraia Pirfo; Fitzpatrick, Michael E.; Gillemot, Ferenc; Horváth, Marta; Horváth, Ákos; Szekely, Richard

    2014-02-18

    This paper focuses on the use of magnetic measurements, using Barkhausen signals to determine the irradiation effects, attempting to predict fracture toughness changes on nuclear reactor structural materials and correlating these measurements to mechanical testing and microstructure. For this study, two types of nuclear reactor materials were investigated: one sensitive to irradiation effects, the JRQ IAEA's reference material (A533B- -type); and one resistant material, 15KH2MFA WWER's reactor pressure vessel steel. The samples were carefully identified within the original heat block, i.e. forged or rolled plate. These calibrated samples were irradiated at different neutron fluences up to 10{sup 23} n/m{sup 2}. We show how microstructural anisotropy can mask the irradiation effects in the magnetic measurements. A correlation between irradiation effects and the magnetic measurements is explained based on this study.

  2. Insight on the inconsistencies of Barkhausen signal measurements for radiation damage on nuclear reactor steel

    NASA Astrophysics Data System (ADS)

    Barroso, Soraia Pirfo; Fitzpatrick, Michael E.; Gillemot, Ferenc; Horváth, Marta; Horváth, Ákos; Szekely, Richard

    2014-02-01

    This paper focuses on the use of magnetic measurements, using Barkhausen signals to determine the irradiation effects, attempting to predict fracture toughness changes on nuclear reactor structural materials and correlating these measurements to mechanical testing and microstructure. For this study, two types of nuclear reactor materials were investigated: one sensitive to irradiation effects, the JRQ IAEA's reference material (A533B- -type); and one resistant material, 15KH2MFA WWER's reactor pressure vessel steel. The samples were carefully identified within the original heat block, i.e. forged or rolled plate. These calibrated samples were irradiated at different neutron fluences up to 1023 n/m2. We show how microstructural anisotropy can mask the irradiation effects in the magnetic measurements. A correlation between irradiation effects and the magnetic measurements is explained based on this study.

  3. Quantitative nuclear magnetic resonance to measure body composition in infants and children

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Quantitative Nuclear Magnetic Resonance (QMR) is being used in human adults to obtain measures of total body fat (FM) with high precision. The current study assessed a device specially designed to accommodate infants and children between 3 and 50 kg (EchoMRI-AH™). Body composition of 113 infants and...

  4. Aerial Radiation Measurements from the Fukushima Dai-ichi Nuclear Power Plant Accident

    SciTech Connect

    Guss, P. P.

    2012-07-16

    This document is a slide show type presentation concerning DOE and Aerial Measuring System (AMS) activities and results with respect to assessing the consequences of the releases from the Fukushima Dai-ichi Nuclear Power Plant. These include ground monitoring and aerial monitoring.

  5. Measuring Radon in Air, Soil and Water: An Introduction to Nuclear Physics for Schools

    ERIC Educational Resources Information Center

    Johansson, K. E.; Nilsson, Ch.; Wachtmeister, S.

    2007-01-01

    With the radon measurement activities at Stockholm House of Science, nuclear and experimental physics is introduced in a way that attracts the attention and interest of the students. These projects give the students the opportunity to use mobile detectors, either in their school, in the House of Science or in their homes. During 2006, 34 radon…

  6. Nuclear magnetic resonance for measurement of body composition in infants and children

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Measurement of body composition in infants and children is currently challenging. Air Displacement Plethysmography (ADP) has not been validated between ages 6 mo and 6 y and the requirement for stillness of the Dual-energy X-ray Absorptiometry (DXA) technique limits its use. Quantitative Nuclear Ma...

  7. An Undergraduate Experiment on Nuclear Lifetime Measurement Using the Doppler Effect

    ERIC Educational Resources Information Center

    Campbell, J. L.; And Others

    1972-01-01

    While designed for a senior undergraduate laboratory, the experiment illustrates the principles involved in the various Doppler techniques currently used in nuclear lifetime studies and demonstrates the versatility of the Ge(Li) detector in applications other than direct energy or intensity measurement. (Author/TS)

  8. A comment on the validity of fragmentation parameters measured in nuclear emulsions. [cosmic ray nuclei

    NASA Technical Reports Server (NTRS)

    Waddington, C. J.

    1978-01-01

    Evidence is reexamined which has been cited as suggesting serious errors in the use of fragmentation parameters appropriate to an airlike medium deduced from measurements made in nuclear emulsions to evaluate corrections for certain effects in balloon-borne observations of cosmic-ray nuclei. Fragmentation parameters for hydrogenlike interactions are calculated and shown to be in overall good agreement with those obtained previously for air. Experimentally measured fragmentation parameters in emulsion are compared with values computed semiempirically, and reasonable agreement is indicated.

  9. A potential nuclear magnetic resonance imaging approach for noncontact temperature measurement

    NASA Technical Reports Server (NTRS)

    Manatt, Stanley L.

    1989-01-01

    It is proposed that in a nuclear magnetic resonance (NMR) imaging experiment that it should be possible to measure temperature through an extended volume. The basis for such a measurement would depend upon sensing a temperature dependent on NMR parameter in an inert, volatile molecule (or fluid) filling the volume of interest. Exploratory work suggest that one suitable candidate for such a purpose might be CH3Cl. Possible parameters, other inert gases and feasible measurement schemes that might provide such temperature measurement are discussed.

  10. The traceability chain of 131I measurements for nuclear medicine in Cuba.

    PubMed

    Oropesa, P; Moreno, Y; Serra, R A; Hernández, A T

    2012-09-01

    The national traceability chain for (131)I activity measurements performed in nuclear medicine in Cuba is described. At the highest (primary) level, liquid scintillation counting employing the CIEMAT/NIST method is used; at the secondary level, a secondary standard radionuclide calibrator is utilized that allows for a quick and simple transference of the measurement unit to the tertiary level of end-users' instruments. The equivalence of Cuban standards and the assessment of measurement uncertainties at the end-user level are determined through the results of measurement comparisons. PMID:22534014

  11. Nuclear Resonance Fluorescence Measurements on ^237Np for Security and Safeguards Applications

    NASA Astrophysics Data System (ADS)

    Angell, C. T.; Joshi, T.; Yee, Ryan; Norman, E. B.; Kulp, W. D.; Warren, G. A.; Korbly, S.; Klimenko, A.; Wilson, C.; Copping, R.; Shuh, D. K.

    2009-10-01

    The smuggling of nuclear material and the diversion of fissile material for covert weapon programs both present grave risks to world security. Methods are needed to detect nuclear material smuggled in cargo, and for proper material accountability in civilian fuel re-processing facilities. Nuclear resonance fluorescence (NRF) is a technique that can address both needs. It is a non-destructive active interrogation method that provides isotope-specific information. It works by using a γ-ray beam to resonantly excite levels in a nucleus and observing the γ-rays emitted whose energy and intensity are characteristic of that isotope. ^237Np presents significant safeguard challenges; it is fissile yet currently has fewer safeguard restrictions. NRF measurements on ^237Np will expand the nuclear database and will permit designing interrogation and assay systems. Measurements were made using the bremsstrahlung beam at the HVRL at MIT on a 7 g target of ^237Np with two incident electron energies of 2.8 and 3.1 MeV. Results will be presented with discussion of the relevant nuclear structure necessary to predict levels in other actinides.

  12. The CERN n_TOF facility: a unique tool for nuclear data measurement

    NASA Astrophysics Data System (ADS)

    Mingrone, F.; Aberle, O.; Andrzejewski, J.; Audouin, L.; Bécares, V.; Bacak, M.; Balibrea-Correa, J.; Barbagallo, M.; Barros, S.; Bečvář, F.; Beinrucker, C.; Berthoumieux, E.; Billowes, J.; Bosnar, D.; Brugger, M.; Caamaño, M.; Calviño, F.; Calviani, M.; Cano-Ott, D.; Cardella, R.; Casanovas, A.; Castelluccio, D. M.; Cerutti, F.; Chen, Y.; Chiaveri, E.; Colonna, N.; Cortés-Giraldo, M. A.; Cortés, G.; Cosentino, L.; Damone, L.; Diakaki, M.; Domingo-Pardo, C.; Dressler, R.; Dupont, E.; Durán, I.; Fernández-Domínguez, B.; Ferrari, A.; Ferreira, P.; Finocchiaro, P.; Furman, V.; Ganesan, S.; Garcia-Rios, A. A.; Gawlik, A.; Gheorghe, I.; Glodariu, T.; Gonçalves, I. F.; Gonzàlez, E.; Goverdovski, A.; Griesmayer, E.; Guerrero, C.; Gunsing, F.; Göbel, K.; Harada, H.; Heftrich, T.; Heinitz, S.; Heyse, J.; Jenkins, G.; Jericha, E.; Käppeler, F.; Kadi, Y.; Katabuchi, T.; Kavrigin, P.; Ketlerov, V.; Khryachkov, V.; Kimura, A.; Kivel, N.; Kokkoris, M.; Krtička, M.; Leal-Cidoncha, E.; Lederer, C.; Leeb, H.; Lerendegui, J.; Lo Meo, S.; Lonsdale, S.; Losito, R.; Macina, D.; Marganiec, J.; Martínez, T.; Massimi, C.; Mastinu, P.; Mastromarco, M.; Matteucci, F.; Maugeri, E. A.; Mendoza, E.; Mengoni, A.; Milazzo, P. M.; Mirea, M.; Montesano, S.; Musumarra, A.; Nolte, R.; Oprea, A.; Patronis, N.; Pavlik, A.; Perkowski, J.; Praena, J.; Quesada, J. M.; Rajeev, K.; Rauscher, T.; Reifarth, R.; Riego-Perez, A.; Rout, P.; Rubbia, C.; Ryan, J. A.; Sabaté-Gilarte, M.; Saxena, A.; Schillebeeckx, P.; Schmidt, S.; Schumann, D.; Sedyshev, P.; Smith, A. G.; Stamatopoulos, A.; Tagliente, G.; Tain, J. L.; Tarifeño-Saldivia, A.; Tassan-Got, L.; Tsinganis, A.; Valenta, S.; Vannini, G.; Variale, V.; Vaz, P.; Ventura, A.; Vlachoudis, V.; Vlastou, R.; Wallner, A.; Warren, S.; Weigand, M.; Weiss, C.; Wolf, C.; Woods, P. J.; Wright, T.; Žugec, P.

    2016-06-01

    The study of the resonant structures in neutron-nucleus cross-sections, and therefore of the compound-nucleus reaction mechanism, requires spectroscopic measurements to determine with high accuracy the energy of the neutron interacting with the material under study. To this purpose, the neutron time-of-flight facility n_TOF has been operating since 2001 at CERN. Its characteristics, such as the high intensity instantaneous neutron flux, the wide energy range from thermal to few GeV, and the very good energy resolution, are perfectly suited to perform high-quality measurements of neutron-induced reaction cross sections. The precise and accurate knowledge of these cross sections plays a fundamental role in nuclear technologies, nuclear astrophysics and nuclear physics. Two different measuring stations are available at the n_TOF facility, called EAR1 and EAR2, with different characteristics of intensity of the neutron flux and energy resolution. These experimental areas, combined with advanced detection systems lead to a great flexibility in performing challenging measurement of high precision and accuracy, and allow the investigation isotopes with very low cross sections, or available only in small quantities, or with very high specific activity. The characteristics and performances of the two experimental areas of the n_TOF facility will be presented, together with the most important measurements performed to date and their physics case. In addition, the significant upcoming measurements will be introduced.

  13. Pulsed, Photonuclear-induced, Neutron Measurements of Nuclear Materials with Composite Shielding

    SciTech Connect

    James Jones; Kevin Haskell; Rich Waston; William Geist; Jonathan Thron; Corey Freeman; Martyn Swinhoe; Seth McConchie; Eric Sword; Lee Montierth; John Zabriskie

    2011-07-01

    Active measurements were performed using a 10-MeV electron accelerator with inspection objects containing various nuclear and nonnuclear materials available at the Idaho National Laboratory’s Zero Power Physics Reactor (ZPPR) facility. The inspection objects were assembled from ZPPR reactor plate materials to evaluate the measurement technologies for the characterization of plutonium, depleted uranium or highly enriched uranium shielded by both nuclear and non-nuclear materials. A series of pulsed photonuclear, time-correlated measurements were performed with unshielded calibration materials and then compared with the more complex composite shield configurations. The measurements used multiple 3He detectors that are designed to detect fission neutrons between pulses of an electron linear accelerator. The accelerator produced 10-MeV bremsstrahlung X-rays at a repetition rate of 125 Hz (8 ms between pulses) with a 4-us pulse width. All inspected objects were positioned on beam centerline and 100 cm from the X-ray source. The time-correlated data was collected in parallel using both a Los Alamos National Laboratory-designed list-mode acquisition system and a commercial multichannel scaler analyzer. A combination of different measurement configurations and data analysis methods enabled the identification of each object. This paper describes the experimental configuration, the ZPPR inspection objects used, and the various measurement and analysis results for each inspected object.

  14. Investigations of defect structures and g factors for octahedral (CrO6)7‑ and (VO6)8‑ clusters in rutile-type crystals

    NASA Astrophysics Data System (ADS)

    Zhu, Lianxuan; Wang, Minjie

    2016-05-01

    The electron paramagnetic resonance (EPR) g factor formulas for Cr5+ and V4+ ions in Al2O3, TiO2 and VO2 crystals are deduced from Jahn-Teller effect and contributions of the charge transfer (CT) levels. The tetragonal distortions. ΔR(R∥‑ R⊥) = ‑0.0184,‑0.0045 and ‑0.0124 nm, and Δ𝜃 = 0∘, ‑ 0.001∘ and 0∘, for Al2O3:Cr5+, TiO2:V4+ and VO2, respectively. The calculations of the g factors agree well with the experimental values. The contributions of the CT levels to g factors increase with the increasing valence state. It must be taken into account in the precise calculations of g factors for the high valence state d1 ions in crystals.

  15. The g-factor of quasi-two-dimensional electrons in InAs/InGaAs/InAlAs inserted-channels

    SciTech Connect

    Pakmehr, Mehdi; Khaetskii, A.; McCombe, B. D.; Bhandari, N.; Cahay, M.; Chiatti, Olivio; Fischer, S. F.; Heyn, C.; Hansen, W.

    2015-08-24

    We have measured the Landau-level spin-splitting of two-dimensional electrons in the composite InAs/InGaAs channels of two InAs/InGaAs/InAlAs heterostructures with different alloy compositions by magnetotransport and THz magneto-photoconductivity in magnetic fields up to 10 T. The structures differ importantly in the mobility of the channel, the electron density and the composition of the barriers. The magnitudes of the experimental g-factors for B along the quantization axis and their anisotropies are larger by at least a factor of 2 than the corresponding calculated single particle values. The angular dependence of many-body exchange contributions and the effects of broadening of Landau–level densities of states are necessary for understanding this behaviour. We find evidence for a marked decrease of the exchange contribution at low perpendicular magnetic fields in the higher mobility sample from coincidence measurements, but no indications of such behaviour in the lower mobility sample.

  16. The g-factor of quasi-two-dimensional electrons in InAs/InGaAs/InAlAs inserted-channels

    NASA Astrophysics Data System (ADS)

    Pakmehr, Mehdi; Khaetskii, A.; McCombe, B. D.; Bhandari, N.; Cahay, M.; Chiatti, Olivio; Fischer, S. F.; Heyn, C.; Hansen, W.

    2015-08-01

    We have measured the Landau-level spin-splitting of two-dimensional electrons in the composite InAs/InGaAs channels of two InAs/InGaAs/InAlAs heterostructures with different alloy compositions by magnetotransport and THz magneto-photoconductivity in magnetic fields up to 10 T. The structures differ importantly in the mobility of the channel, the electron density and the composition of the barriers. The magnitudes of the experimental g-factors for B along the quantization axis and their anisotropies are larger by at least a factor of 2 than the corresponding calculated single particle values. The angular dependence of many-body exchange contributions and the effects of broadening of Landau-level densities of states are necessary for understanding this behaviour. We find evidence for a marked decrease of the exchange contribution at low perpendicular magnetic fields in the higher mobility sample from coincidence measurements, but no indications of such behaviour in the lower mobility sample.

  17. Nuclear data for r-process models from ion trap measurements

    NASA Astrophysics Data System (ADS)

    Clark, Jason

    2016-06-01

    To truly understand how elements are created in the universe via the astrophysical r process, accurate nuclear data are required. Historically, the isotopes involved in the r process have been difficult to access for study, but the development of new facilities and measurement techniques have put many of the r-process isotopes within reach. This paper will discuss the new CARIBU facility at Argonne National Laboratory and two pieces of experimental equipment, the Beta-decay Paul Trap and the Canadian Penning Trap, that will dramatically increase the nuclear data available for models of the astrophysical r process.

  18. Residential housing and nuclear attack: The ineffectiveness of current civil defence measures

    SciTech Connect

    Diacon, D.

    1985-01-01

    Diane Diacon of the Building and Social Housing Foundation has conducted an independent investigation of the question, and in this book she sums up the results. She first examines the nature of nuclear attack, and then goes on to explore the usefulness of specially-designed nuclear shelters and the likely disruption of essential services in the case of war. She concludes that the protection afforded by residential housing is in fact extremely poor, and that the civil defence measures contemplated by government bureaucrats are likely to be utterly ineffective.

  19. Simultaneous measurements of the X-ray and nuclear shock-bang times in ICF plasmas

    NASA Astrophysics Data System (ADS)

    Sutcliffe, G.; Sio, H.; Rinderknecht, H.; Frenje, J.; Zylstra, A.; Gatu Johnson, M.; Seguin, F.; Li, C. K.; Petrasso, R.; Rygg, J. R.; Macphee, A.; MacKinnon, A.; Le Pape, S.; Berzak Hopkins, L.; Regan, S. P.; Sangster, C.; Kilkenny, J.; Olson, R.

    2015-11-01

    Recent measurements of nuclear and x-ray shock-bang times in ICF implosions at OMEGA and the NIF provide new constraints on implosion modeling and may elucidate the underlying physics of e-i equilibration during the shock phase. As the ions are predominantly heated by the converging and rebounding shock, the ion temperature is initially much higher than the electron temperature and the difference relaxes at the e-i equilibration time scale. Nuclear and x-ray bang times are expected to differ because of different temperature dependence. At OMEGA, nuclear shock-bang time and burn history are routinely measured using streak camera diagnostics, while x-ray self-emission is observed with x-ray framing cameras. We are exploring the possibility of measuring both x-ray and nuclear shock-bang times with a single diagnostic with high relative accuracy, and will discuss the precision with which they can be made and the diagnostics necessary at OMEGA. This work was supported in part by NLUF, US DOE, and LLE.

  20. Deflection Measurements of a Thermally Simulated Nuclear Core Using a High-Resolution CCD-Camera

    NASA Technical Reports Server (NTRS)

    Stanojev, B. J.; Houts, M.

    2004-01-01

    Space fission systems under consideration for near-term missions all use compact. fast-spectrum reactor cores. Reactor dimensional change with increasing temperature, which affects neutron leakage. is the dominant source of reactivity feedback in these systems. Accurately measuring core dimensional changes during realistic non-nuclear testing is therefore necessary in predicting the system nuclear equivalent behavior. This paper discusses one key technique being evaluated for measuring such changes. The proposed technique is to use a Charged Couple Device (CCD) sensor to obtain deformation readings of electrically heated prototypic reactor core geometry. This paper introduces a technique by which a single high spatial resolution CCD camera is used to measure core deformation in Real-Time (RT). Initial system checkout results are presented along with a discussion on how additional cameras could be used to achieve a three- dimensional deformation profile of the core during test.

  1. Error reduction in gamma-spectrometric measurements of nuclear materials enrichment

    NASA Astrophysics Data System (ADS)

    Zaplatkina, D.; Semenov, A.; Tarasova, E.; Zakusilov, V.; Kuznetsov, M.

    2016-06-01

    The paper provides the analysis of the uncertainty in determining the uranium samples enrichment using non-destructive methods to ensure the functioning of the nuclear materials accounting and control system. The measurements were performed by a scintillation detector based on a sodium iodide crystal and the semiconductor germanium detector. Samples containing uranium oxide of different masses were used for the measurements. Statistical analysis of the results showed that the maximum enrichment error in a scintillation detector measurement can reach 82%. The bias correction, calculated from the data obtained by the semiconductor detector, reduces the error in the determination of uranium enrichment by 47.2% in average. Thus, the use of bias correction, calculated by the statistical methods, allows the use of scintillation detectors to account and control nuclear materials.

  2. Dry, portable calorimeter for nondestructive measurement of the activity of nuclear fuel

    DOEpatents

    Beyer, Norman S.; Lewis, Robert N.; Perry, Ronald B.

    1976-01-01

    The activity of a quantity of heat-producing nuclear fuel is measured rapidly, accurately and nondestructively by a portable dry calorimeter comprising a preheater, an array of temperature-controlled structures comprising a thermally guarded temperature-controlled oven, and a calculation and control unit. The difference between the amounts of electric power required to maintain the oven temperature with and without nuclear fuel in the oven is measured to determine the power produced by radioactive disintegration and hence the activity of the fuel. A portion of the electronic control system is designed to terminate a continuing sequence of measurements when the standard deviation of the variations of the amount of electric power required to maintain oven temperature is within a predetermined value.

  3. Three-dimensional direct measurement of cardiomyocyte volume, nuclearity, and ploidy in thick histological sections

    NASA Astrophysics Data System (ADS)

    Bensley, Jonathan Guy; de Matteo, Robert; Harding, Richard; Black, Mary Jane

    2016-04-01

    Quantitative assessment of myocardial development and disease requires accurate measurement of cardiomyocyte volume, nuclearity (nuclei per cell), and ploidy (genome copies per cell). Current methods require enzymatically isolating cells, which excludes the use of archived tissue, or serial sectioning. We describe a method of analysis that permits the direct simultaneous measurement of cardiomyocyte volume, nuclearity, and ploidy in thick histological sections. To demonstrate the utility of our technique, heart tissue was obtained from four species (rat, mouse, rabbit, sheep) at up to three life stages: prenatal, weaning and adulthood. Thick (40 μm) paraffin sections were stained with Wheat Germ Agglutinin-Alexa Fluor 488 to visualise cell membranes, and DAPI (4‧,6-diamidino-2-phenylindole) to visualise nuclei and measure ploidy. Previous methods have been restricted to thin sections (2–10 μm) and offer an incomplete picture of cardiomyocytes. Using confocal microscopy and three-dimensional image analysis software (Imaris Version 8.2, Bitplane AG, Switzerland), cardiomyocyte volume, nuclearity, and ploidy were measured. This method of staining and analysis of cardiomyocytes enables accurate morphometric measurements in thick histological sections, thus unlocking the potential of archived tissue. Our novel time-efficient method permits the entire cardiomyocyte to be visualised directly in 3D, eliminating the need for precise alignment of serial sections.

  4. Three-dimensional direct measurement of cardiomyocyte volume, nuclearity, and ploidy in thick histological sections.

    PubMed

    Bensley, Jonathan Guy; De Matteo, Robert; Harding, Richard; Black, Mary Jane

    2016-01-01

    Quantitative assessment of myocardial development and disease requires accurate measurement of cardiomyocyte volume, nuclearity (nuclei per cell), and ploidy (genome copies per cell). Current methods require enzymatically isolating cells, which excludes the use of archived tissue, or serial sectioning. We describe a method of analysis that permits the direct simultaneous measurement of cardiomyocyte volume, nuclearity, and ploidy in thick histological sections. To demonstrate the utility of our technique, heart tissue was obtained from four species (rat, mouse, rabbit, sheep) at up to three life stages: prenatal, weaning and adulthood. Thick (40 μm) paraffin sections were stained with Wheat Germ Agglutinin-Alexa Fluor 488 to visualise cell membranes, and DAPI (4',6-diamidino-2-phenylindole) to visualise nuclei and measure ploidy. Previous methods have been restricted to thin sections (2-10 μm) and offer an incomplete picture of cardiomyocytes. Using confocal microscopy and three-dimensional image analysis software (Imaris Version 8.2, Bitplane AG, Switzerland), cardiomyocyte volume, nuclearity, and ploidy were measured. This method of staining and analysis of cardiomyocytes enables accurate morphometric measurements in thick histological sections, thus unlocking the potential of archived tissue. Our novel time-efficient method permits the entire cardiomyocyte to be visualised directly in 3D, eliminating the need for precise alignment of serial sections. PMID:27048757

  5. Three-dimensional direct measurement of cardiomyocyte volume, nuclearity, and ploidy in thick histological sections

    PubMed Central

    Bensley, Jonathan Guy; De Matteo, Robert; Harding, Richard; Black, Mary Jane

    2016-01-01

    Quantitative assessment of myocardial development and disease requires accurate measurement of cardiomyocyte volume, nuclearity (nuclei per cell), and ploidy (genome copies per cell). Current methods require enzymatically isolating cells, which excludes the use of archived tissue, or serial sectioning. We describe a method of analysis that permits the direct simultaneous measurement of cardiomyocyte volume, nuclearity, and ploidy in thick histological sections. To demonstrate the utility of our technique, heart tissue was obtained from four species (rat, mouse, rabbit, sheep) at up to three life stages: prenatal, weaning and adulthood. Thick (40 μm) paraffin sections were stained with Wheat Germ Agglutinin-Alexa Fluor 488 to visualise cell membranes, and DAPI (4′,6-diamidino-2-phenylindole) to visualise nuclei and measure ploidy. Previous methods have been restricted to thin sections (2–10 μm) and offer an incomplete picture of cardiomyocytes. Using confocal microscopy and three-dimensional image analysis software (Imaris Version 8.2, Bitplane AG, Switzerland), cardiomyocyte volume, nuclearity, and ploidy were measured. This method of staining and analysis of cardiomyocytes enables accurate morphometric measurements in thick histological sections, thus unlocking the potential of archived tissue. Our novel time-efficient method permits the entire cardiomyocyte to be visualised directly in 3D, eliminating the need for precise alignment of serial sections. PMID:27048757

  6. Measurements of extinct fission products in nuclear bomb debris: Determination of the yield of the Trinity nuclear test 70 y later.

    PubMed

    Hanson, Susan K; Pollington, Anthony D; Waidmann, Christopher R; Kinman, William S; Wende, Allison M; Miller, Jeffrey L; Berger, Jennifer A; Oldham, Warren J; Selby, Hugh D

    2016-07-19

    This paper describes an approach to measuring extinct fission products that would allow for the characterization of a nuclear test at any time. The isotopic composition of molybdenum in five samples of glassy debris from the 1945 Trinity nuclear test has been measured. Nonnatural molybdenum isotopic compositions were observed, reflecting an input from the decay of the short-lived fission products (95)Zr and (97)Zr. By measuring both the perturbation of the (95)Mo/(96)Mo and (97)Mo/(96)Mo isotopic ratios and the total amount of molybdenum in the Trinity nuclear debris samples, it is possible to calculate the original concentrations of the (95)Zr and (97)Zr isotopes formed in the nuclear detonation. Together with a determination of the amount of plutonium in the debris, these measurements of extinct fission products allow for new estimates of the efficiency and yield of the historic Trinity test. PMID:27382169

  7. In situ radiation measurements at the former Soviet Nuclear Test Site

    SciTech Connect

    Tipton, W.J.

    1996-06-01

    A team from the Remote Sensing Laboratory conducted a series of in situ radiological measurements at the former Soviet Nuclear Test Site near Semipalatinsk, Kazakhstan, during the period of July 21-30, 1994. The survey team measured the terrestrial gamma radiation at selected areas on the site to determine the levels of natural and man-made radiation. The survey was part of a cooperative effort between the United States team and teams of radiation scientists from the National Nuclear Center of the Republic of Kazakhstan and the V.G. Khlopin Radium Institute in St. Petersburg, Russia. In addition to in situ radiation measurements made by the United States and Russian teams, soil samples were collected and analyzed by the Russian and Kazakhstani teams. All teams conducted their measurements at ten locations within the test site. The United States team also made a number of additional measurements to locate and verify the positions of three potential fallout plumes containing plutonium contamination from nonnuclear tests. In addition, the United States team made several measurements in Kurchatov City, the housing area used by personnel and their families who work(ed) at the test sites. Comparisons between the United States and Russian in situ measurements and the soil sample results are presented as well as comparisons with a Soviet aerial survey conducted in 1990-1991. The agreement between the different types of measurements made by all three countries was quite good.

  8. Development and calibration of the shielded measurement system for fissile contents measurements on irradiated nuclear fuel in dry storage.

    SciTech Connect

    Mosby, W. R.; Jensen, B. A.

    2002-05-31

    In recent years there has been a trend towards storage of Irradiated Nuclear Fuel (INF) in dry conditions rather than in underwater environments. At the same time, the Department of Energy (DOE) has begun encouraging custodians of INF to perform measurements on INF for which no recent fissile contents measurement data exists. INF, in the form of spent fuel from Experimental Breeder Reactor 2 (EBR-II), has been stored in close-fitting, dry underground storage locations at the Radioactive Scrap and Waste Facility (RSWF) at Argonne National Laboratory-West (ANL-W) for many years. In Fiscal Year 2000, funding was obtained from the DOE Office of Safeguards and Security Technology Development Program to develop and prepare for deployment a Shielded Measurement System (SMS) to perform fissile content measurements on INF stored in the RSWF. The SMS is equipped to lift an INF item out of its storage location, perform scanning neutron coincidence and high-resolution gamma-ray measurements, and restore the item to its storage location. The neutron and gamma-ray measurement results are compared to predictions based on isotope depletion and Monte Carlo neutral-particle transport models to provide confirmation of the accuracy of the models and hence of the fissile material contents of the item as calculated by the same models. This paper describes the SMS and discusses the results of the first calibration and validation measurements performed with the SMS.

  9. CALMOS: Innovative device for the measurement of nuclear heating in material testing reactors

    SciTech Connect

    Carcreff, H.

    2011-07-01

    An R and D program has been carried out since 2002 in order to improve gamma heating measurements in the 70 MWth OSIRIS Material Testing Reactor operated by CEA's Nuclear Energy Div. at the Saclay research center. Throughout this program an innovative calorimetric probe associated to a specific handling system has been designed in order to make measurements both along the fissile height and on the upper part of the core, where nuclear heating rates still remain high. Two mock-ups of the probe were manufactured and tested in 2005 and 2009 in ex-core area of OSIRIS reactor for the process validation, while a displacement system has been especially designed to move the probe axially. A final probe has been designed thanks to modeling results and to preliminary measurements obtained with mock-ups irradiated to a heating level of 2W/g, This paper gives an overview of the development, describes the calorimetric probe, and expected advantages such as the possibility to use complementary methods to get the nuclear heating measurement. Results obtained with mock-ups irradiated in ex-core area of the reactor are presented and discussed. (authors)

  10. Low level radioactivity measurement in support of the CTBTO. Comprehensive Nuclear-Test-Ban Treaty Organization

    PubMed

    Schulze; Auer; Werzi

    2000-07-01

    Radioactivity measurements, together with three other technologies: seismic, hydroacoustic and infrasound, are able to detect, identify and locate nuclear explosions down to 1 kt. Eighty stations worldwide, with a sensitivity of 10-30 microBq/m3 for 140Ba and 1 mBq/m m3 for 133Xe, have been or will be established in order to provide an estimated 90% detection probability within 10 days after a nuclear explosion. The equipment for manual stations--the high volume samplers, high sensitivity HPGe detectors and auxiliary measurement systems, as well as the automatic stations are described. The problems and results of atmospheric transport, site location as well as equipment and station operation are discussed. PMID:10879833

  11. Measurement of left ventricular ejection fraction in pediatric patients using the nuclear stethoscope

    SciTech Connect

    Spicer, R.L.; Rabinovitch, M.; Rosenthal, A.; Pitt, B.

    1984-01-01

    Left ventricular (LV) ejection fraction (EF) was measured in 25 patients, aged 2 weeks to 20 years (mean 8.6 years), using a portable nonimaging scintillation stethoscope. Technically satisfactory studies were obtained in 23 patients. LVEF was validated by cineangiography in 19 patients and by standard gated blood pool scintigraphy in 4. EF measured by the nuclear stethoscope correlated well with values obtained by cineangiography or scintigraphy over a wide range of EF values (18 to 79%). In children younger than 5 years (n . 11), the correlation was less satisfactory than in those older than 5 years. Although modifications in the instrument and further clinical trials with the stethoscope are needed before the device becomes clinically useful to pediatric cardiologists, our data indicate that the nuclear stethoscope can provide reliable assessment of LVEF in pediatric patients.

  12. Atomic mass measurements and nuclear spectroscopy at TRISTAN. Progress report, July 1, 1980-January 31, 1981

    SciTech Connect

    Brenner, D.S.

    1981-02-01

    This research program is concerned with measuring atomic masses and decay schemes of short-lived, neutron-rich fission products with the TRISTAN on-line mass separator located at the High Flux Beam Reactor (HFBR), Brookhaven National Laboratory. The determination of accurate masses for neutron-rich nuclei is useful in refining mass equations wich, in turn, are important for calculations related to astrophysical processes and to control and safety of nuclear reactors. During the period covered by this report, efforts have been to aid Brookhaven personnel in the installation and testing of TRISTAN and the associated computer systems, and to begin a program of measurements of ..beta..-ray end-point energies and nuclear decay schemes following successful demonstration of the facility. 2 figures.

  13. Intelligent monitor functional model with ionization chamber for mixed nuclear radiation field measurements

    SciTech Connect

    Valcov, N.; Purghel, L.; Celarel, A.

    1998-12-31

    By using the statistical discrimination technique, the components of an ionization current, due to a mixed radiation field, may be simultaneously measured. A functional model, including a series manufactured gamma-ray ratemeter was done, as an intermediate step in the design of specialized nuclear instrumentation, in order to check the concept of statistical discrimination method. The obtained results are in good agreement with the estimations of the statistical discrimination method.

  14. Nuclear spin effects in optical lattice clocks

    SciTech Connect

    Boyd, Martin M.; Zelevinsky, Tanya; Ludlow, Andrew D.; Blatt, Sebastian; Zanon-Willette, Thomas; Foreman, Seth M.; Ye Jun

    2007-08-15

    We present a detailed experimental and theoretical study of the effect of nuclear spin on the performance of optical lattice clocks. With a state-mixing theory including spin-orbit and hyperfine interactions, we describe the origin of the {sup 1}S{sub 0}-{sup 3}P{sub 0} clock transition and the differential g factor between the two clock states for alkaline-earth-metal(-like) atoms, using {sup 87}Sr as an example. Clock frequency shifts due to magnetic and optical fields are discussed with an emphasis on those relating to nuclear structure. An experimental determination of the differential g factor in {sup 87}Sr is performed and is in good agreement with theory. The magnitude of the tensor light shift on the clock states is also explored experimentally. State specific measurements with controlled nuclear spin polarization are discussed as a method to reduce the nuclear spin-related systematic effects to below 10{sup -17} in lattice clocks.

  15. Compressibility, the measurement of surface tension, and particle size in molecular or nuclear matter.

    PubMed

    Dixmier, Marc

    2006-02-15

    It is shown that the interface shrinkage resulting from the capillary pressure difference between both sides of a curved interface is the product of a "standard shrinkage"kappagamma (kappa is the isothermal compressibility, gamma the interfacial tension) by a dimensionless factor that depends only on the shape of the sample of matter under study. The behaviour of the standard shrinkage in the critical domain shows that it cannot be a measure of the thickness of the liquid-vapour interface in that domain. The standard shrinkage of classical liquids somewhat above triple point is usually near to 0.048 v(c)(1/3) (v(c) is the critical molecular volume); exceptions to this rule are discussed. The variation of the standard shrinkage along the liquid-vapour coexistence curves of water and argon is presented; the effect of the interface shrinkage on the measured surface tension of liquids can become important within about 15% of the critical temperature. The standard shrinkage of solids is less than that of the corresponding liquids, and is of no consequence when measuring the surface tension of solids. The standard shrinkage of the nuclear fluid is 0.23 fm=0.09 v(c)(1/3). The saturation density of infinite nuclear matter is about 9% less than its value in atomic nuclei, and a term proportional to A(1/3) (A is the mass number) must be added to the nuclear binding energy formula. PMID:16266717

  16. Nuclear data production, calculation and measurement: a global overview of the gamma heating issue

    NASA Astrophysics Data System (ADS)

    Colombier, A.-C.; Amharrak, H.; Fourmentel, D.; Ravaux, S.; Régnier, D.; Gueton, O.; Hudelot, J.-P.; Lemaire, M.

    2013-03-01

    The gamma heating evaluation in different materials found in current and future generations of nuclear reactor (EPRTM, GENIV, MTR-JHR), is becoming an important issue especially for the design of many devices (control rod, heavy reflector, in-core & out-core experiments…). This paper deals with the works started since 2009 in the Reactor Studies Department of CEA Cadarache in ordre to answer to several problematic which have been identified as well for nuclear data production and calculation as for experimental measurement methods. The selected subjects are: Development of a Monte Carlo code (FIFRELIN) to simulate the prompt fission gamma emission which represents the major part of the gamma heating production inside the core Production and qualification of new evaluations of nuclear data especially for radiative capture and inelastic neutron scattering which are the main sources of gamma heating out-core Development and qualification of a recommended method for the total gamma heating calculation using the Monte Carlo simulation code TRIPOLI-4 Development, test and qualification of new devices dedicated to the in-core gamma heating measurement as well in MTR-JHR as in zero power facilities (EOLE-MINERVE) of CEA, Cadarache to increase the experimental measurement accuracy.

  17. Measured 19F(α,n) with VANDLE for Nuclear Safeguards

    NASA Astrophysics Data System (ADS)

    Peters, William; Clement, R. C. C.; Smith, M. S.; Pain, S.; Febbraro, M.; Pittman, S.; Thomspon, S.; Grinder, M.; Cizewski, J. A.; Reingold, C.; Manning, B.; Burcher, S.; Bardayan, D. W.; Tan, W.-P.; Stech, E.; Smith, M. K.; Avetisyan, R.; Gyurjinyan, A.; Lowe, M.; Ilyushkin, S.; Grzywacz, R.; Madurga, M.; Paulauskas, S. V.; Taylor, S. Z.; Smith, K.

    2015-10-01

    One of the most promising non-destructive assay (NDA) methods to monitor UF6 canisters consists of measuring gross neutron rates induced by uranium-decay alpha particles reacting with the fluorine and emitting a neutron. This method currently lacks reliable nuclear data on the 19F(α,n) reaction cross section to determine an accurate neutron yield rate for a given sample of UF6. We have measured the cross section and coincident neutron spectrum for the alpha-decay energy range using the VANDLE system. This experiment had two parts: first at Notre Dame with a LaF3 target and and a pulsed alpha-particle beam, and second at ORNL with a windowless He-gas target and a 19F beam. The motivation for this measurement and cross section results will be presented. This work is funded in part by the DOE Office of Science, the National Nuclear Security Administration SSAA and the Office of Defense Nuclear Nonproliferation R&D, and the NSF.

  18. Study for Nuclear Structures of 22-35Na Isotopes via Measurements of Reaction Cross Sections

    NASA Astrophysics Data System (ADS)

    Suzuki, Shinji

    2014-09-01

    T. Ohtsubo, M. Nagashima, T. Ogura, Y. Shimbara (Grad. Sch. of Sc., Niigata Univ.), M.Takechi, H. Geissel, M. Winkler (GSI), D. Nishimura, T. Sumikama (Dept. of Phys., Tokyo Univ. of Sc.), M. Fukuda, M. Mihara, H. Uenishi (Dept. of Phys., Osaka Univ.), T. Kuboki, T. Suzuki, T. Yamaguchi, H. Furuki, C. S. Lee, K. Sato (Dept. of Phys., Saitama Univ.), A. Ozawa, H. Ohnishi, T. Moriguchi, S. Fukuda, Y. Ishibashi, D. Nagae, R. Nishikiori, T. Niwa (Inst. of Phys., Univ. of Tsukuba), N. Aoi (RCNP), Rui-Jiu Chen, N. Inabe, D. Kameda, T. Kubo, M. Lantz, T. Ohnishi, K. Okumura, H. Sakurai, H. Suzuki, H. Takeda, S. Takeuchi, K. Tanaka, Y. Yanagisawa (RIKEN), De-Qing Fang, Yu-Gang Ma (SINAP), T. Izumikawa (RI Ctr., Niigata Univ.), and S. Momota (Fac. of Engn., Kochi Univ. of Tech.) Reaction cross sections (σR) for 22-35Na isotopes have been measured at around 240 MeV/nucleon. The σR for 22-35Na were measured for the first time. Enhancement in cross sections is clearly observed from the systematics for stable nuclei, for isotopes with large mass numbers. These enhancement can be mainly ascribed to the nuclear deformation. We will discuss the nuclear structure (neutron skin, nuclear shell structure) for neutron-excess Na isotopes. T. Ohtsubo, M. Nagashima, T. Ogura, Y. Shimbara (Grad. Sch. of Sc., Niigata Univ.), M.Takechi, H. Geissel, M. Winkler (GSI), D. Nishimura, T. Sumikama (Dept. of Phys., Tokyo Univ. of Sc.), M. Fukuda, M. Mihara, H. Uenishi (Dept. of Phys., Osaka Univ.), T. Kuboki, T. Suzuki, T. Yamaguchi, H. Furuki, C. S. Lee, K. Sato (Dept. of Phys., Saitama Univ.), A. Ozawa, H. Ohnishi, T. Moriguchi, S. Fukuda, Y. Ishibashi, D. Nagae, R. Nishikiori, T. Niwa (Inst. of Phys., Univ. of Tsukuba), N. Aoi (RCNP), Rui-Jiu Chen, N. Inabe, D. Kameda, T. Kubo, M. Lantz, T. Ohnishi, K. Okumura, H. Sakurai, H. Suzuki, H. Takeda, S. Takeuchi, K. Tanaka, Y. Yanagisawa (RIKEN), De-Qing Fang, Yu-Gang Ma (SINAP), T. Izumikawa (RI Ctr., Niigata Univ.), and S. Momota (Fac. of Engn

  19. [The Chinese nuclear test and 'atoms for peace' as a measure for preventing nuclear armament of Japan: the nuclear non-proliferation policy of the United States and the introduction of light water reactors into Japan, 1964-1968].

    PubMed

    Yamazaki, Masakatsu

    2014-07-01

    Japan and the United States signed in 1968 a new atomic energy agreement through which US light-water nuclear reactors, including those of the Fukushima Daiichi Nuclear Power Plant of Tokyo Electric Power Company, were to be introduced into Japan. This paper studies the history of negotiations for the 1968 agreement using documents declassified in the 1990s in the US and Japan. After the success of the Chinese nuclear test in October 1964, the United States became seriously concerned about nuclear armament of other countries in Asia including Japan. Expecting that Japan would not have its own nuclear weapons, the US offered to help the country to demonstrate its superiority in some fields of science including peaceful nuclear energy to counter the psychological effect of the Chinese nuclear armament. Driven by his own political agenda, the newly appointed Prime Minister Eisaku Sato responded to the US expectation favorably. When he met in January 1965 with President Johnson, Sato made it clear that Japan would not pursue nuclear weapons. Although the US continued its support after this visit, it nevertheless gave priority to the control of nuclear technology in Japan through the bilateral peaceful nuclear agreement. This paper argues that the 1968 agreement implicitly meant a strategic measure to prevent Japan from going nuclear and also a tactic to persuade Japan to join the Nuclear Non -Proliferation Treaty. PMID:25296517

  20. Recent Results of Nuclear Mass Measurements at Storage Ring in IMP

    NASA Astrophysics Data System (ADS)

    Xu, H. S.; Zhang, Y. H.

    2014-09-01

    Recent commissioning of the Cooler Storage Ring at the Heavy Ion Research Facility in Lanzhou (HIRFL-CSR) has allowed us for direct mass measurements at the Institute of Modern Physics in Lanzhou (IMP), Chinese Academy of Sciences. A series of isochronous mass measurements have been carried out in the past few years using 78Kr, 86Kr, 58Ni, and 112Sn beams. The main results and the present status are presented in this talk, and the implications of these results with respect to nuclear structures and nucleosynthesis in the rp-process of x-ray bursts are discussed.

  1. Results on the neutron energy distribution measurements at the RECH-1 Chilean nuclear reactor

    NASA Astrophysics Data System (ADS)

    Aguilera, P.; Molina, F.; Romero-Barrientos, J.

    2016-07-01

    Neutron activations experiments has been perform at the RECH-1 Chilean Nuclear Reactor to measure its neutron flux energy distribution. Samples of pure elements was activated to obtain the saturation activities for each reaction. Using - ray spectroscopy we identify and measure the activity of the reaction product nuclei, obtaining the saturation activities of 20 reactions. GEANT4 and MCNP was used to compute the self shielding factor to correct the cross section for each element. With the Expectation-Maximization algorithm (EM) we were able to unfold the neutron flux energy distribution at dry tube position, near the RECH-1 core. In this work, we present the unfolding results using the EM algorithm.

  2. Analysis of the nuclear measurement program for an optimized BR2 core configuration

    SciTech Connect

    Van Den Branden, G.; Kalcheva, S.; Sikik, E.; Koonen, E.

    2013-07-01

    This paper presents the analysis of the results of the Nuclear Measurement Program (NMP) executed during the shut-down of cycle 05/2012 of the BR2 reactor. The aim of the NMP was to determine the properties of a reactor core load with a new configuration of the control rods and to evaluate/verify the predicted numerical results by MCNPX. The methods used for the interpretation of the measurement results include combinations of an analytical method for determination of the axial relative control rod efficiency and least square techniques. (authors)

  3. A two-axis goniometer for low-temperature nuclear magnetic resonance measurements on single crystals

    NASA Astrophysics Data System (ADS)

    Shiroka, T.; Casola, F.; Mesot, J.; Bachmann, W.; Ott, H.-R.

    2012-09-01

    We report on the construction of a two-axis goniometer intended for low-temperature, single-crystal nuclear magnetic resonance (NMR) measurements. With the use of home-made and commercially available parts, our simple probe-head design achieves good sensitivity, while maintaining a high angular precision and the ability to orient samples also when cooled to liquid helium temperatures. The probe with the goniometer is adapted to be inserted into a commercial 4He-flow cryostat, which fits into a wide-bore superconducting solenoid magnet. Selected examples of NMR measurements illustrate the operation of the device.

  4. A multiple sampling time projection ionization chamber for nuclear fragment tracking and charge measurement

    NASA Astrophysics Data System (ADS)

    Bauer, G.; Bieser, F.; Brady, F. P.; Chance, J. C.; Christie, W. F.; Gilkes, M.; Lindenstruth, V.; Lynen, U.; Müller, Walter F. J.; Romero, J. L.; Sann, H.; Tull, C. E.; Warren, P.

    1997-02-01

    A detector has been developed for the tracking and charge measurement of the projectile fragment nuclei produced in relativistic nuclear collisions. This device, MUSIC II, is a second generation Multiple Sampling Ionization Chamber (MUSIC), and employs the principles of ionization and time projection chambers. It provides unique charge determination for charges Z≥6, and excellent track position measurement. MUSIC II has been used most recently with the EOS (Equation of State) TPC and other EOS Collaboration detectors. Earlier it was used with other systems in experiments at the Heavy Ion Superconducting Spectrometer (HISS) facility at Lawrence Berkeley Laboratory and the ALADIN spectrometer at GSI.

  5. Measurement of leaching from simulated nuclear-waste glass using radiotracers

    SciTech Connect

    Bates, J.K.; Jardine, L.J.; Steindler, M.J.

    1982-09-01

    The use of radiotracer spiking as a method of measuring the leaching from simulated nuclear-waste glass is shown to give results comparable with other analytical detection methods. The leaching behavior of /sup 85/Sr, /sup 106/Ru, /sup 133/Ba, /sup 137/Cs, /sup 141/Ce, /sup 152/Eu, and other isotopes is measured for several defense waste glasses. These tests show that radiotracer spiking is a sensitive, multielement technique that can provide leaching data, for actual waste elements, that are difficult to obtain by other methods. Additionally, a detailed procedure is described that allows spiked glass to be prepared with a suitable distribution of radionuclides.

  6. Prospects of Optical Single Atom Detection in Noble Gas Solids for Measurements of Rare Nuclear Reactions

    NASA Astrophysics Data System (ADS)

    Singh, Jaideep; Bailey, Kevin G.; Lu, Zheng-Tian; Mueller, Peter; O'Connor, Thomas P.; Xu, Chen-Yu; Tang, Xiaodong

    2013-04-01

    Optical detection of single atoms captured in solid noble gas matrices provides an alternative technique to study rare nuclear reactions relevant to nuclear astrophysics. I will describe the prospects of applying this approach for cross section measurements of the ^22Ne,,),25Mg reaction, which is the crucial neutron source for the weak s process inside of massive stars. Noble gas solids are a promising medium for the capture, detection, and manipulation of atoms and nuclear spins. They provide stable and chemically inert confinement for a wide variety of guest species. Because noble gas solids are transparent at optical wavelengths, the guest atoms can be probed using lasers. We have observed that ytterbium in solid neon exhibits intersystem crossing (ISC) which results in a strong green fluorescence (546 nm) under excitation with blue light (389 nm). Several groups have observed ISC in many other guest-host pairs, notably magnesium in krypton. Because of the large wavelength separation of the excitation light and fluorescence light, optical detection of individual embedded guest atoms is feasible. This work is supported by DOE, Office of Nuclear Physics, under contract DE-AC02-06CH11357.

  7. A confirmatory research approach to the measurement of EMI/RFI in commercial nuclear power plants

    SciTech Connect

    Kercel, S.W.

    1995-04-01

    The Oak Ridge National Laboratory (ORNL) is conducting confirmatory research on the measurement of electromagnetic/radio frequency interference (EMI/RFI) in nuclear power plants. While it makes a good beginning, the currently available research data are not sufficient to characterize the EMI/RFI environment of the typical nuclear plant. Data collected over several weeks at each of several observation points are required to meet this need. To collect the required data, several approaches are examined, the most promising of which is the relatively new technology of application specific spectral receivers. While several spectral receiver designs have been described in the literature, none is well suited for nuclear power plant EMI/RFI surveys. This paper describes the development of two receivers specifically designed for nuclear power plant EMI/RFI surveys. One receiver surveys electric fields between 5 MHz and 8 GHz, while the other surveys magnetic fields between 305 Hz and 5 MHz. The results of field tests at TVA`s Bull Run Fossil Plant are reported.

  8. A confirmatory research approach to the measurement of EMI/RFI in commercial nuclear power plants

    SciTech Connect

    Kercel, S.W.

    1995-02-01

    The Oak Ridge National Laboratory (ORNL) is conducting confirmatory research on the measurement of electromagnetic/radio frequency interference (EMI/RFI) in nuclear power plants while it makes a good beginning, the currently available research data are not sufficient to characterize the EMI/RFI environment of the typical nuclear plant. Data collected over several weeks at each of several observation points are required to meet this need. To collect the required data, several approaches are examined, the most promising of which is the relatively new technology of application specific spectral receivers. While several spectral receiver designs have been described in the literature, none is well suited for nuclear power plant EMI/RFI surveys. This paper describes the development of two receivers specifically designed for nuclear power plant EMI/RFI surveys. One receiver surveys electric fields between 5 MHz and 8 GHz, while the other surveys magnetic fields between 305 Hz and 5 MHz. The results of field tests at TVA`s Bull Run Fossil Plant are reported.

  9. Measurement of Scintillation and Ionization Yield and Scintillation Pulse Shape from Nuclear Recoils in Liquid Argon

    SciTech Connect

    Cao, H.

    2015-05-26

    We have measured the scintillation and ionization yield of recoiling nuclei in liquid argon as a function of applied electric field by exposing a dual-phase liquid argon time projection chamber (LAr-TPC) to a low energy pulsed narrow band neutron beam produced at the Notre Dame Institute for Structure and Nuclear Astrophysics. Liquid scintillation counters were arranged to detect and identify neutrons scattered in the TPC and to select the energy of the recoiling nuclei. We also report measurements of the scintillation yields for nuclear recoils with energies from 10.3 to 57.3 keV and for median applied electric fields from 0 to 970 V/cm. For the ionization yields, we report measurements from 16.9 to 57.3 keV and for electric fields from 96.4 to 486 V/cm. Furthermore, we report the observation of an anticorrelation between scintillation and ionization from nuclear recoils, which is similar to the anticorrelation between scintillation and ionization from electron recoils. Assuming that the energy loss partitions into excitons and ion pairs from 83mKr internal conversion electrons is comparable to that from 207Bi conversion electrons, we obtained the numbers of excitons (Nex) and ion pairs (Ni) and their ratio (Nex/Ni) produced by nuclear recoils from 16.9 to 57.3 keV. Motivated by arguments suggesting direction sensitivity in LAr-TPC signals due to columnar recombination, a comparison of the light and charge yield of recoils parallel and perpendicular to the applied electric field is presented for the first time.

  10. Measurement of Scintillation and Ionization Yield and Scintillation Pulse Shape from Nuclear Recoils in Liquid Argon

    DOE PAGESBeta

    Cao, H.

    2015-05-26

    We have measured the scintillation and ionization yield of recoiling nuclei in liquid argon as a function of applied electric field by exposing a dual-phase liquid argon time projection chamber (LAr-TPC) to a low energy pulsed narrow band neutron beam produced at the Notre Dame Institute for Structure and Nuclear Astrophysics. Liquid scintillation counters were arranged to detect and identify neutrons scattered in the TPC and to select the energy of the recoiling nuclei. We also report measurements of the scintillation yields for nuclear recoils with energies from 10.3 to 57.3 keV and for median applied electric fields from 0more » to 970 V/cm. For the ionization yields, we report measurements from 16.9 to 57.3 keV and for electric fields from 96.4 to 486 V/cm. Furthermore, we report the observation of an anticorrelation between scintillation and ionization from nuclear recoils, which is similar to the anticorrelation between scintillation and ionization from electron recoils. Assuming that the energy loss partitions into excitons and ion pairs from 83mKr internal conversion electrons is comparable to that from 207Bi conversion electrons, we obtained the numbers of excitons (Nex) and ion pairs (Ni) and their ratio (Nex/Ni) produced by nuclear recoils from 16.9 to 57.3 keV. Motivated by arguments suggesting direction sensitivity in LAr-TPC signals due to columnar recombination, a comparison of the light and charge yield of recoils parallel and perpendicular to the applied electric field is presented for the first time.« less