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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-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.

  3. Extraction of the electron mass from g -factor measurements on light hydrogenlike ions

    NASA Astrophysics Data System (ADS)

    Zatorski, J.; Sikora, B.; Karshenboim, S. G.; Sturm, S.; Köhler-Langes, F.; Blaum, K.; Keitel, C. H.; Harman, Z.

    2017-07-01

    The determination of the electron mass from Penning-trap measurements with 5+12C ions and from theoretical results for the bound-electron g factor is described in detail. Some recently calculated contributions slightly shift the extracted mass value. Prospects of a further improvement of the electron mass are discussed both from the experimental and from the theoretical points of view. Measurements with +4He ions will enable a consistency check of the electron-mass value, and in the future an improvement of the 4He nuclear mass and a determination of the fine-structure constant.

  4. QCD Nuclear g-factor and the Spin-Statistics Theorem

    NASA Astrophysics Data System (ADS)

    Ward, Thomas

    2015-04-01

    Consideration of the composite three-quark nucleon spin structure and its Pauli spin-statistics follows a new QCD g-factor with implications for the magnetic dipole moments of nucleons and their form factors. The reformulation of the nucleon magnetic moments using the new QCD nucleon g-factor is shown to be in striking agreement with global polarized and unpolarized e-p scattering data using the Sachs electric and magnetic form factors, thus reconciling long standing discrepancies between measurements. Additionally, the introduction of QCD isospin symmetry breaking (ISB) strange quarks terms contained within the meson-baryon exchange currents allow the partially conserved EM axial currents to be restored as well as providing a precise measure of the strange quark probabilities of the nucleons. Work performed under the auspices of US Department of Energy.

  5. 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.

  6. Toward tests of QED and CPT with improved electron and positron g-factor measurements

    NASA Astrophysics Data System (ADS)

    Novitski, Elise; Dorr, Joshua; Fogwell Hoogerheide, Shannon; Gabrielse, Gerald

    2013-05-01

    We describe progress toward improved measurements of the electron and positron g-factors using quantum jump spectroscopy between the lowest quantum states of either particle trapped in a 100 mK cylindrical Penning trap. In a new apparatus--designed for improved stability and a better geometry for cavity-assisted sideband cooling--we have trapped a single electron, driven and observed single cyclotron transitions, and trapped positrons in a loading trap. This should enable measurements of both g-factors with better than the 0.28 ppt precision of the best electron value (the most precise measurement of a fundamental property of an elementary particle), thereby improving the positron value by a factor of more than 15., These measurements, in combination with QED theory relating the electron g-factor to α, will improve on the most precise determination of α, the fine structure constant. The comparison of this value with an independent measurement of α is the most precise test of QED. The comparison of the e- and e+ g-factors will improve upon the best test of CPT symmetry in a lepton system. This work is supported by the NSF

  7. 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.

  8. g-factor measurements at RISING: The cases of \\chem{{}^{127}Sn} and \\chem{{}^{128}Sn}

    NASA Astrophysics Data System (ADS)

    Atanasova, L.; Balabanski, D. L.; Chamoli, S. K.; Hass, M.; Simpson, G. S.; Bazzacco, D.; Becker, F.; Bednarczyk, P.; Benzoni, G.; Blasi, N.; Blazhev, A.; Bracco, A.; Brandau, C.; Caceres, L.; Camera, F.; Crespi, F. C. L.; Detistov, P.; Doornenbal, P.; Fahlander, C.; Farnea, E.; Georgiev, G.; Gerl, J.; Gladnishki, K. A.; Górska, M.; Grebosz, J.; Hoischen, R.; Ilie, G.; Ionescu-Bujor, M.; Iordachescu, A.; Jungclaus, A.; Lo Bianco, G.; Kmiecik, M.; Kojouharov, I.; Kurz, N.; Lakshmi, S.; Lozeva, R.; Maj, A.; Montanari, D.; Neyens, G.; Pfützner, M.; Pietri, S.; Podolyák, Zs.; Prokopowicz, W.; Rudolph, D.; Rusev, G.; Saito, T. R.; Saltarelli, A.; Schaffner, H.; Schwengner, R.; Tashenov, S.; Valiente-Dobón, J. J.; Vermeulen, N.; Walker, J.; Werner-Malento, E.; Wieland, O.; Wollersheim, H. J.; Grawe, H.; Hjorth-Jensen, M.

    2010-08-01

    We report on g-factor measurements of the 19/2+ T1/2=4.5(3) μs isomer in 127Sn and the 10+ T1/2=2.69(23) μs isomer in 128Sn. These isomers were produced and spin-aligned in relativistic heavy-ion fragmentation at GSI and were selected and separated by the GSI fragment separator (FRS). The γ-rays of the isomeric decay were detected by the RISING γ-ray spectrometer. The method of time-differential perturbed angular distributions was utilized. The measured g-factors, g(19/2+; 127Sn)=- 0.17(2) and g(10+; 128Sn)=- 0.20(4), are compared with shell model calculations. The measured g-factors confirm the predominantly νh11/2- 2 and ν(s1/2- 1h11/2-2) character of the 10+ and 19/2- isomers in 128Sn and 127Sn, respectively. The results demonstrate the feasibility of the method for similar measurements in exotic neutron-rich nuclei.

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

    SciTech Connect

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

    2016-07-07

    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 {sup 106}Cd to study excited states of {sup 110}Sn and the beam nuclei itself will be presented.

  10. 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.

  11. Conduction electron g-factors in ruthenium and osmium from de Haas-van Alphen measurements

    NASA Astrophysics Data System (ADS)

    Startsev, V. E.; Coleridge, P. T.; Templeton, I. M.; Fawcett, E.; Muir, C.; Perz, J. M.

    1984-04-01

    Conduction electron g-factors have been deduced from de Haas-van Alphen line shapes in the hexagonal group VIII 4 d transition metal ruthenium and the electronically analogous 5 d metal osmium. The values for orbits normal to [0001] are 1.8±0.1 and 1.3±0.1 for the ellipsoids centered on the line LM in ruthenium and osmium, respectively, and 1.9±0.2 for the Γ-centered ellipsoid in ruthenium. The more marked suppression of the g-factor in osmium, where spin-orbit coupling is stronger, is consistent with recent theoretical studies of transition metal g-factor trends.

  12. A g-factor puzzle for the N=38 nuclei:First measurement of the ^70Ge 41^+ magnetic moment.

    NASA Astrophysics Data System (ADS)

    Boutachkov, Plamen; Kumbartzki, G.; Benczer-Koller, N.; Robinson, S.; Escuderos, A.; Stefanova, E.; Sharon, Y.; Zamick, L.; McCutchan, E.; Werner, V.; Ai, H.; Gurdal, G.; Heinz, A.; Qian, J.; Williams, E.; Winkler, R.; Garnsworthy, A.; Thompson, N.; Maier-Komor, P.

    2006-10-01

    The transient field technique in inverse kinematics allows g-factor studies of short-lived states. This method gives information on both the sign and the magnitude of the g factor. In a recent experiment, the g factor of the 4^+1 state of ^6830Zn38 was measured to be -0.37(17) suggesting a significant neutron g9/2 contribution to the wave function[1]. However, shell model calculations in the 0f5/2,1p3/2,1p1/2,0g9/2 space [1] predict a positive, nearly zero g factor. To obtain more information on this region we measured the magnetic moment of the 4^+1 in ^7032Ge38. The measurement was performed at WNSL, Yale, using a 275 MeV ^70Ge beam and a multilayered C+Gd+Cu target. A positive g factor was obtained. The measured magnetic moment was compared to full fp shell model calculations which we performed with the code ANTOINE using several effective interactions. The results were in good agreement with the experiment. The experiment and the implications of the new results will be discussed.1. J. Leske et al., Phys. Rev C 72, 044301 (2005).

  13. g-Factor of Composite Fermions around ν = 3/2 from Angular Dependent Activation Energy Measurements.

    NASA Astrophysics Data System (ADS)

    Yeh, A. S.; Du, R. R.; Stormer, H. L.; Tsui, D. C.; Pfeiffer, L. N.; West, K. W.

    1997-03-01

    The fractional quantum Hall states around ν = 3/2 have been successfully interpreted as composite fermions (CFs) with a spin and a g-factor. In Reference 1, the g-factor was obtained from fixed temperature magnetoresistance measurements at several specific angles at which the energy gaps vanished. In the present experiment, we probe the CF energy gaps at arbitrary angle. We directly observe the opening and closing of the gaps, supporting the picture of composite fermions with a spin. At fixed filling factor, we calculate CF g-factors from the rate of change in the energy gap with respect to the total magnetic field. Our GaAs/AlGaAs heterostructure of density n = 1.13x10^11 cm-2 and mobility μ = 6.8x10^6 cm^2/V s shows activated behavior for close to two orders of magnitude for most angles between 0 degrees and 57.1 degrees. We find g-factors of 0.59 for ν = 5/3, 0.76 for ν = 4/3, and 0.56 for ν = 8/5. These g-factors agree to within 10% of previous results. [1] R. R. Du, A. S. Yeh, H. L. Stormer, D. C. Tsui, L. N. Pfeiffer, K. W. West, Phys. Rev. Lett 75, 3926 (1995).

  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. Spin-polarized state quantum filter used to measure spin-polarized state relaxation time and g-factor

    NASA Astrophysics Data System (ADS)

    Makarov, Vladimir I.; Khmelinskii, Igor

    2013-02-01

    A novel method for measurement of g-factor and spin-lattice relaxation time of spin-polarized states in nano-layers of different chemical nature was developed. This method is based on usage of spin-polarized state quantum filter, which was created and tested earlier [V. I. Makarov et al., J Appl. Phys. 110, 063717 (2011) and V. I. Makarov et al., J Appl. Phys. 112, 084310 (2012). The spin state parameters were measured in nanolayers of different materials (Fe, Au, and Si) in function of such experimental parameters as the layer thickness and temperature. The phenomenological model developed earlier for steady-state conditions was presently extended to include time dependence and successfully used in the data analysis. Qualitative models were proposed that explain the observed dependences, forming the basis for future theoretical developments.

  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. Electronic g-factor measurement from ENDOR-induced EPR patterns: malonic acid and guanine hydrochloride dihydrate.

    PubMed

    Kang, Junseog; Tokdemir, Sibel; Shao, Jun; Nelson, William H

    2003-11-01

    Measurement of electronic g-factors (g) from radicals in irradiated organic crystals is generally difficult because the overall EPR pattern is usually the composite of several components, e.g., from multiple radicals and from multiple magnetic sites. However, when an ENDOR line is fully resolved, the method of ENDOR-induced EPR (EI-EPR, or EIE) in principle permits identification of the EPR pattern from the individual component yielding the line. To examine this method as an approach useful for measuring g, we used it to measure those of known radicals in two different crystal systems. First, to verify correspondence of the EIE and EPR sufficient for using EIE patterns to extract g, we used both EIE and EPR to measure g of (*CH(COOH)(2) from irradiated crystals of malonic acid. Then, to illustrate the procedure applied to a system giving a more complex EPR pattern, we used EIE to measure g of the O6-protonated anion radical of guanine in irradiated guanine.HCl.2H(2)O crystals. EPR results from the malonic acid radical are g(max)=2.00374(2), g(mid)=2.00331(2), and g(min)=2.00234(3); EIE results from the same radical are g(max)=2.00375(2), g(mid)=2.00334(2), and g(min)=2.00238(2), where numbers in parentheses indicate statistical uncertainties in the respective least significant digits. In addition, eigenvectors from the two sets of measurements agree to approximately 1 degrees. Results from the guanine radical are g(max)=2.00490(2), g(mid)=2.00318(4), and g(min)=2.00218(4). (The uncertainties should reliably indicate relative accuracy, while absolute accuracy is within +/-0.0002 as indicated by simultaneous measurement of Cr(3+) in MgO.)

  19. 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}

  20. 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.

  1. Toward lifetime and g factor measurements of short-lived states in the vicinity of 208Pb

    NASA Astrophysics Data System (ADS)

    Ralet, D.; Georgiev, G.; E Stuchbery, A.; Clément, E.; Lemasson, A.; Michelagnoli, C.; Rejmund, M.; Atanasova, L.; Balabanski, D. L.; Bocchi, G.; Carroll, R.; Dewald, A.; Dudouet, J.; Fornal, B.; de France, G.; Franchoo, S.; Fransen, C.; Müller-Gatermann, C.; Goasduff, A.; Gadea, A.; Jacquot, B.; John, P. R.; Kocheva, D.; Konstantinopoulos, T.; Korichi, A.; Kusoglu, A.; Lenzi, S. M.; Leoni, S.; Ljungvall, J.; Lozeva, R.; Maj, A.; Navin, A.; Perez, R.; Pietralla, N.; Shand, C.; Stezowski, O.; Yordanov, D.

    2017-05-01

    The multi-nucleon transfer reaction mechanism was used to produce and study nuclei in the vicinity of 208Pb. This mass region is a test case for the nuclear shell model. The mass identification of the fragments was performed with the large acceptance magnetic spectrometer VAMOS++ coupled to the AGATA γ-tracking array. This experiment aimed to determine both lifetimes and gyromagnetic ratios of excited states with the Cologne plunger device. The analysis indicates promising results with the possibility to determine several new lifetimes in this region.

  2. Electromagnetically induced absorption and transparency in degenerate two level systems of metastable Kr atoms and measurement of Landé g-factor

    NASA Astrophysics Data System (ADS)

    Kale, Y. B.; Tiwari, V. B.; Mishra, S. R.; Singh, S.; Rawat, H. S.

    2016-12-01

    We report electromagnetically induced absorption (EIA) and transparency (EIT) resonances of sub-natural linewidth in degenerate two level systems (DTLSs) of metastable 84Kr (84Kr*) and 83Kr (83Kr*) atoms. Using the spectrally narrow EIA signals obtained corresponding to the closed hyperfine transition 4p55s[3/2]2(F=13/2) to 4p55p[5/2]3(F‧ = 15 / 2) in 83Kr* atom, we have measured the Landé g-factor (gF) for the lower hyperfine level involved in this transition by application of small values of magnetic field of few Gauss.

  3. 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.

  4. Perpendicular ferromagnetic resonance measurements of damping and Landég- factor in sputtered (Co2Mn)1-xGex thin films

    NASA Astrophysics Data System (ADS)

    Nembach, H. T.; Silva, T. J.; Shaw, J. M.; Schneider, M. L.; Carey, M. J.; Maat, S.; Childress, J. R.

    2011-08-01

    X-ray diffraction (XRD), magnetometry, and ferromagnetic resonance (FMR) measurements were performed on sputtered thin films of the nominal Heusler alloy (Co2Mn)1-xGex with varying Ge content and annealing temperatures. XRD indicates some degree of B2 alloy formation, with strong (110) texturing. FMR measurements were performed in a perpendicular geometry that minimized the contribution of two-magnon scattering to the linewidth. The FMR data indicate a significant increase in linewidth for samples that lack a well-defined (220) peak, presumably as a result of inhomogeneous line broadening. Samples annealed at 200 °C exhibit decreasing Landau-Lifshitz damping with increasing Ge content, while samples annealed at 245 and 300 °C have a nonlinear dependence of linewidth on frequency. The nonlinear component of the linewidth data was successfully fit with a generalized theory of slowly relaxing impurities, originally proposed by Van Vleck and Orbach. The modified theory includes the possibility of transverse coherence during the relaxation process. Magnetometry and FMR spectroscopy results were analyzed in the context of Malozemoff's generalized Slater-Pauling (GSP) theory, with the conclusion that the Ge sites support a significant negative-polarized spin density of several tens of percent. The GSP analysis results were consistent with a more conventional analysis of the spectroscopic g-factor that is appropriate for alloys. The proportionality of the strength of the slow-relaxer contribution to the damping suggests that the negatively polarized Ge atoms are acting as the slowly relaxing impurities in question.

  5. Nuclear Enterprise Performance Measurement

    DTIC Science & Technology

    2011-03-01

    Scheduling Effectiveness and Deferred Discrepancy rate show the management’s ability to efficiently use human and material resources while...assigned personnel is a good gauge of the utilization of human resources , the effectiveness of the unit’s training program and it’s ability to...training throughput is an important measure of a unit’s training quality and management oversight of human resources . Certification training can take

  6. Gyroscopic g factor of rare earth metals

    NASA Astrophysics Data System (ADS)

    Ogata, Y.; Chudo, H.; Ono, M.; Harii, K.; Matsuo, M.; Maekawa, S.; Saitoh, E.

    2017-02-01

    We develop the in situ magnetization measurement apparatus for observing the Barnett effect consisting of a fluxgate sensor, a high speed rotor with frequencies of up to 1.5 kHz, and a magnetic shield at room temperature. The effective magnetic field (Barnett field) in a sample arising from rotation magnetizes the sample and is proportional to the rotational frequency. The gyroscopic g factor, g ' , of rare earth metals, in particular, Gd, Tb, and Dy, was estimated to be 2.00 ± 0.08, 1.53 ± 0.17, and 1.15 ± 0.32, respectively, from the slopes of the rotation dependence of the Barnett field. This study provides a technique to determine the g ' factor even in samples where the spectroscopic method may not be available.

  7. 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

    SciTech Connect

    Wang, Jiyin; Huang, Shaoyun E-mail: syhuang@pku.edu.cn; Lei, Zijin; Pan, Dong; Zhao, Jianhua; Xu, H. Q. E-mail: syhuang@pku.edu.cn

    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/SiO{sub 2} 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 Δ{sub ST} ∼ 2.3 meV, a strong spin-orbit interaction of Δ{sub SO} ∼ 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.

  8. Spin-alignment and g-factor measurement of the I^{π} = 12+ isomer in 192Pb produced in the relativistic-energy fragmentation of a 238U beam

    NASA Astrophysics Data System (ADS)

    Kmiecik, M.; Maj, A.; Gerl, J.; Neyens, G.; Atanasova, L.; Balabanski, D. L.; Becker, F.; Bednarczyk, P.; Benzoni, G.; Blasi, N.; Bracco, A.; Brambilla, S.; Caceres, L.; Camera, F.; Ciemała, M.; Crespi, F. C. L.; Chamoli, S. K.; Chmel, S.; Daugas, J. M.; Detistov, P.; Doornenbal, P.; Georgiev, G.; Gladnishki, K.; Górska, M.; Grawe, H.; Grȩbosz, J.; Hass, M.; Hoischen, R.; Ilie, G.; Ionescu-Bujor, M.; Jolie, J.; Kojuharov, I.; Krasznahorkay, A.; Kulessa, R.; Lach, M.; Lakshmi, S.; Leoni, S.; Lo Bianco, G.; Lozeva, R.; Maier, K. H.; Mallion, S.; Mazurek, K.; Mȩczyński, W.; Million, B.; Montanari, D.; Myalski, S.; Petrache, C.; Pfützner, M.; Pietri, S.; Podolyák, Zs.; Prokopowicz, W.; Rudolph, D.; Saito, N.; Saito, T. R.; Saltarelli, A.; Simpson, G. S.; Styczeń, J.; Vermeulen, N.; Werner-Malento, E.; Wieland, O.; Wollersheim, H. J.; Ziȩbliński, M.

    2010-08-01

    The feasibility of measuring g -factors using the TDPAD method applied to high-energy, heavy fragmentation products is explored. The 2623keV ensuremath I^{π}=12^+ isomer in 192Pb with tau = 1.57 μs has been produced using the fragmentation of a 1 A GeV 238U beam. The results presented demonstrate for the first time that such heavy nuclei produced in a fragmentation reaction with a relativistic beam are sufficiently well spin-aligned. Moreover, the rather large value of the alignment, 28(10)% of the maximum possible, is preserved during the separation process allowing the determination of magnetic moments. The measured values of the lifetime, tau = 1.54(9) μs, and the g -factor, g = - 0.175(20) , agree with the results of previous investigations using fusion-evaporation reactions.

  9. 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.

  10. 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.

  11. Perpendicular ferromagnetic resonance measurements of damping and the Landé g-factor in sputtered (Co 2Mn)(1 - x) Ge xthin films

    NASA Astrophysics Data System (ADS)

    Nembach, Hans

    2011-03-01

    We analyzed vector network analyzer-ferromagnetic resonance data for sputtered polycrystalline (Co 2 Mn)(1 - x) Ge x thin films measured in a perpendicular configuration to minimize two magnon scattering. The films were grown with varying Ge content and subjected to post-deposition annealing at 200, 245, and 300circ; C. We can adequately fit the data with the slow relaxing impurity model for damping, similar to what was successfully used to explain enhanced damping in RE- doped Permalloy films. However, it was required to generalize the theory to include coherence effects that modify the original fluctuating field correlation function from a damped exponential to an exponentially damping cosine. We find that the spectroscopic splitting factor g is a clearly decreasing function of Ge content for 245 and 300circ; C anneal samples. Analysis of the content dependence for g provides strong evidence of a significant negative spin polarization between -0.15 and -0.35 spins at the Ge sites. This is consistent with our analysis of magnetometry data in the context of generalized Slater Pauling (GSP) theory, which presumes that the minority band density of states has a deep minimum at the Fermi energy. GSP analysis yields a spin polarization of -0.25 at the Ge sites. The substantial antiferromagnetic spin polarization of the Ge sites, in addition to the correlation of the slow relaxing damping strength with Ge content, suggests that Ge atoms, perhaps in the form of point defects in the Co sub-lattice, are acting as the slow relaxing impurities. Finally, successful fitting of linewidth data with a model that includes coherence during the relaxation process indicates slight transverse as well as longitudinal exchange coupling between the Ge ``impurities'' and the magnetization, giving rise to mixing of the electronic energy levels responsible for the relaxation process.

  12. g factors of coexisting isomeric states in {sup 188}Pb

    SciTech Connect

    Ionescu-Bujor, M.; Iordachescu, A.; Marginean, N.; Suliman, G.; Bucurescu, D.; Marginean, R.; Ur, C. A.; Brandolini, F.; Lenzi, S. M.; Pavan, P.; Vedova, F. Della; Napoli, D. R.; Chmel, S.; Medina, N. H.; Ribas, R. V.

    2010-02-15

    The g factors of the 12{sup +}, 11{sup -}, and 8{sup -} isomeric states in {sup 188}Pb were measured using the time-differential perturbed angular distribution method as g(12{sup +})=-0.179(6), g(11{sup -})=+1.03(3), and g(8{sup -})=-0.037(7). The g factor of the 12{sup +} state follows the observed slight down-sloping evolution of the g factors of the i{sub 13/2}{sup 2} neutron spherical states with decreasing N. The g factors of the 11{sup -} and 8{sup -} isomers proposed as oblate and prolate deformed states, respectively, were interpreted within the rotational model, using calculated and empirical g factor values for the involved single-particle orbitals.

  13. 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.

  14. Nuclear data measurement activities at CIAE

    NASA Astrophysics Data System (ADS)

    Ruan, Xichao; Jiang, Liyang; Yang, Yi; Liu, Shilong; Nie, Yangbo; Wang, Zhaohui; Chen, Xiongjun; Yu, Weixiang; Ge, Zhigang

    2017-09-01

    China Institute of Atomic Energy (CIAE) is one of the most important bases for nuclear data measurement in China. In this paper, the nuclear data measurement activities at CIAE in recent years are presented. The secondary neutron emission DX and DDX measurement, the integral experiment for nuclear data benchmarking, the excitation function measurement, the neutron induced fission yields measurement and the gamma production yields measurement carried out in recent years are introduced. Furthermore, the progress of some new facilities and proposed plans (e.g. A Gamma ray Total Absorption Facility (GTAF) for (n,γ) reaction cross section measurement, A 3He detector array for (n,2n) reaction cross section measurement, the back streaming white neutron beam for nuclear data measurement at China Spallation Neutron Source (CSNS)) are also presented.

  15. g factor of the 21+ state of Hf172

    NASA Astrophysics Data System (ADS)

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

    2009-11-01

    The g factor of the 21+ state of Hf172 was measured using the perturbed angular correlation technique in a static external magnetic field. The result, g(21+)=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.

  16. Neutron nuclear data measurements for criticality safety

    NASA Astrophysics Data System (ADS)

    Guber, Klaus; Paradela, Carlos; Heyse, Jan; Kopecky, Stefan; Schillebeeckx, Peter; Siegler, Peter

    2017-09-01

    To support the US Department of Energy Nuclear Criticality Safety Program, neutron-induced cross section experiments were performed at the Geel Electron Linear Accelerator of the Joint Research Center Site Geel, European Union. Neutron capture and transmission measurements were carried out using metallic natural cerium and vanadium samples. Together with existing data, the measured data will be used for a new evaluation and will be submitted with covariances to the ENDF/B nuclear data library.

  17. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    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.

  19. Mass-spectrometric measurements for nuclear safeguards

    SciTech Connect

    Carter, J.A.; Smith, D.H.; Walker, R.L.

    1982-01-01

    The need of an on-site inspection device to provide isotopic ratio measurements led to the development of a quadrupole mass spectrometer mounted in a van. This mobile laboratory has the ability, through the use of the resin bead technique, to acquire, prepare, and analyze samples of interest to nuclear safeguards. Precision of the measurements is about 1 to 2%.

  20. Advanced nuclear measurements LDRD -- Sensitivity analysis

    SciTech Connect

    Dreicer, J.S.

    1999-02-01

    This component of the Advanced Nuclear Measurements LDRD-PD has focused on the analysis and methodologies to quantify and characterize existing inventories of weapons and commercial fissile materials, as well as to, anticipate future forms and quantities to fissile materials. Historically, domestic safeguards had been applied to either pure uniform homogeneous material or to well characterized materials. The future is different simplistically, measurement challenges will be associated with the materials recovered from dismantled nuclear weapons in the US and Russia subject to disposition, the residues and wastes left over from the weapons production process, and from the existing and growing inventory of materials in commercial/civilian programs. Nuclear measurement issues for the fissile materials coming from these sources are associated with homogeneity, purity, and matrix effects. Specifically, these difficult-to-measure fissile materials are heterogeneous, impure, and embedded in highly shielding non-uniform matrices. Currently, each of these effects creates problems for radiation-based assay and it is impossible to measure material that has a combination of all these effects. Nuclear materials control and measurement is a dynamic problem requiring a predictive capability. This component has been tasked with helping select which future problems are the most important to target, during the last year accomplishments include: characterization of weapons waste fissile materials, identification of measurement problem areas, defining instrument requirements, and characterization of commercial fissile materials. A discussion of accomplishments in each of these areas is presented.

  1. g factor of an electron or muon bound by an arbitrary central potential

    SciTech Connect

    Karshenboim, S.G.; Lee, R.N.; Milstein, A.I.

    2005-10-15

    We consider the g factor of a spin-1/2 particle (electron or muon) bound by an arbitrary central field. We present an approach that allows one to express the relativistic g factor in terms of the binding energy. We derive the general expression for the correction to the g factor caused by a deviation of the central potential from the Coulomb one. As the application of this method, we consider the corrections to the g factor due to the finite nuclear size, including vacuum polarization radiative correction. The effect of the anomalous magnetic moment is also taken into account.

  2. 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.

  3. The Landé-g factor in heterostructures

    NASA Astrophysics Data System (ADS)

    Cardoso, J. L.; Pereyra, P.

    2005-05-01

    We have studied the behavior of the Shubnikov-de Haas oscillations in magnetoresistance under applied magnetic fields with an arbitrary orientation. Different procedures to measure the Landé-g factor have been used in the literature. We propose four unambiguous methods and formulas for the evaluation of this quantity. The Landé-g factor obtained using these formulas compares within the 5% with the reported results of Brosig et al. [1] in InAs - AlSb quantum wells, Bompadre et al. [2] for Bismuth crystals, Kobayashi et al. [3] measuring magnetoresistance as a function of the gate Voltage and F. Fang et al. [4] for InAs - GaSb heterostructure.

  4. 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.

  5. Measuring Nuclear Effects with MINERvA

    NASA Astrophysics Data System (ADS)

    Fiorentini, G.; Minerva Collaboration

    2011-04-01

    MINERνA (Main INjector Experiment for ν-A) is a neutrino scattering experiment in the 1-10 GeV energy range in the NuMI high-intensity neutrino beam at the Fermi National Accelerator Laboratory. MINERνA is now taking data and it was designed to measure neutrino-nucleus cross sections on a variety of different materials (C, Fe, Pb, He, H2O) allowing the study of nuclear effects and the A-dependence in neutrino interactions. This talk will present the current status in the analysis of inclusive charge current events in the iron, lead, and plastic targets.

  6. 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.

  7. Nuclear Resonance Fluorescence Measurements of High Explosives

    SciTech Connect

    Caggiano, Joseph A.; Warren, Glen A.; Korbly, Steve; Hasty, R.; Klimenko, A.; Park, William H.

    2007-12-31

    Pacific Northwest National Laboratory and Passport Systems have collaborated to perform Nuclear Resonance Fluorescence experiments using several high quality high-explosive simulant samples. These measurements were conducted to determine the feasibility of finding and characterizing high explosive material by NRF interrogation. Electron beams of 5.1, 5.3, 8, and 10 MeV were used to produce bremsstrahlung photon beams, which irradiated the samples. The gamma-ray spectra were collected using high-purity germanium detectors. Nitrogen-to-carbon ratios of the high-explosive simulants were extracted from the 5.1 and 5.3 MeV data and compare favorably with accepted values. Analysis of the 8 and 10 MeV data is in progress; preliminary isotopic comparisons within the samples are consistent with the expected results.

  8. A shielded measurement system for irradiated nuclear fuel measurements

    SciTech Connect

    Mosby, W.R.; Aumeier, S.E.; Klann, R.T.

    1999-07-01

    The US Department of Energy (DOE) is driving a transition toward dry storage of irradiated nuclear fuel (INF), toward characterization of INF for final disposition, and toward resumption of measurement-based material control and accountability (MC and A) efforts for INF. For these reasons, the ability to efficiently acquire radiological measurements of INF in a dry environment is important. The DOE has recently developed a guidance document proposing MC and A requirements for INF. The intent of this document is to encourage the direct measurement of INF on inventory within DOE. The guidance document reinforces and clarifies existing material safeguards requirements as they pertain to INF. Validation of nuclear material contents of non-self-protecting INF must be accomplished by direct measurement, application of validated burnup codes using qualified initial fissile content, burnup data, and age or by other valid means. The fuel units must remain intact with readable identification numbers. INF may be subject to periodic inventories with visual item accountability checks. Quantitative measurements may provide greater assurance of the integrity of INF inventories at a lower cost and with less personnel exposure than visual item accountability checks. Currently, several different approaches are used to measure the radiological attributes of INF. Although these systems are useful for a wide variety of applications, there is currently no relatively inexpensive measurement system that is readily deployable for INF measurements for materials located in dry storage. The authors present the conceptual design of a shielded measurement system (SMS) that could be used for this purpose. The SMS consists of a shielded enclosure designed to house a collection of measurement systems to allow measurements on spent fuel outside of a hot cell. The phase 1 SMS will contain {sup 3}He detectors and ionization chambers to allow for gross neutron and gamma-ray measurements. The phase 2

  9. Spin g -factor due to electronic interactions in graphene

    NASA Astrophysics Data System (ADS)

    Menezes, Natália; Alves, Van Sérgio; Marino, E. C.; Nascimento, Leonardo; Nascimento, Leandro O.; Morais Smith, C.

    2017-06-01

    The gyromagnetic factor is an important physical quantity relating the magnetic-dipole moment of a particle to its spin. The electron spin g -factor in vacuo is one of the best model-based theoretical predictions ever made, showing agreement with the measured value up to ten parts per trillion [J. Schwinger, Phys. Rev. 73, 416 (1948), 10.1103/PhysRev.73.416; R. S. Van Dyck, Jr. et al., Phys. Rev. Lett. 59, 26 (1987), 10.1103/PhysRevLett.59.26; D. Hanneke et al., Phys. Rev. Lett. 100, 120801 (2008), 10.1103/PhysRevLett.100.120801; T. Aoyama et al., Phys. Rev. Lett. 109, 111807 (2012), 10.1103/PhysRevLett.109.111807]. However, for electrons in a material the g -factor is modified with respect to its value in vacuo because of environment interactions. Here, we show how interaction effects lead to the spin g -factor correction in graphene by considering the full electromagnetic interaction in the framework of pseudo-QED [A. Kovner et al., Phys. Rev. B 42, 4748 (1990), 10.1103/PhysRevB.42.4748; N. Dorey et al., Nucl. Phys. B 386, 614 (1992), 10.1016/0550-3213(92)90632-L; S. Teber, Phys. Rev. D 86, 025005 (2012), 10.1103/PhysRevD.86.025005; S. Teber, Phys. Rev. D 89, 067702 (2014), 10.1103/PhysRevD.89.067702; E. C. Marino, Nucl. Phys. B 408, 551 (1993), 10.1016/0550-3213(93)90379-4]. We compare our theoretical prediction with experiments performed on graphene deposited on SiO2 and SiC, and we find a very good agreement between them.

  10. Nonlinear Ultrasonic Measurements in Nuclear Reactor Environments

    NASA Astrophysics Data System (ADS)

    Reinhardt, Brian T.

    Several Department of Energy Office of Nuclear Energy (DOE-NE) programs, such as the Fuel Cycle Research and Development (FCRD), Advanced Reactor Concepts (ARC), Light Water Reactor Sustainability, and Next Generation Nuclear Power Plants (NGNP), are investigating new fuels, materials, and inspection paradigms for advanced and existing reactors. A key objective of such programs is to understand the performance of these fuels and materials during irradiation. In DOE-NE's FCRD program, ultrasonic based technology was identified as a key approach that should be pursued to obtain the high-fidelity, high-accuracy data required to characterize the behavior and performance of new candidate fuels and structural materials during irradiation testing. The radiation, high temperatures, and pressure can limit the available tools and characterization methods. In this thesis, two ultrasonic characterization techniques will be explored. The first, finite amplitude wave propagation has been demonstrated to be sensitive to microstructural material property changes. It is a strong candidate to determine fuel evolution; however, it has not been demonstrated for in-situ reactor applications. In this thesis, finite amplitude wave propagation will be used to measure the microstructural evolution in Al-6061. This is the first demonstration of finite amplitude wave propagation at temperatures in excess of 200 °C and during an irradiation test. Second, a method based on contact nonlinear acoustic theory will be developed to identify compressed cracks. Compressed cracks are typically transparent to ultrasonic wave propagation; however, by measuring harmonic content developed during finite amplitude wave propagation, it is shown that even compressed cracks can be characterized. Lastly, piezoelectric transducers capable of making these measurements are developed. Specifically, three piezoelectric sensors (Bismuth Titanate, Aluminum Nitride, and Zinc Oxide) are tested in the Massachusetts

  11. Nuclear Mass Measurement and Evaluation Relevant to Astrophysics

    NASA Astrophysics Data System (ADS)

    Wang, Meng

    Nuclear mass data are crucial input for the astrophysics models. Thanks to the developments of radioactive nuclear beam facilities and novel mass spectrometers, the experimental knowledge of nuclear masses has been continuously expanding to the exotic nuclei far from the stability which play a critical role in astrophysics. The recent progress and future perspective of mass measurement relevant to astrophysics will be discussed. By evaluating all available experimental data from nuclear reactions, radioactive decays and direct mass measurements, the Atomic Mass Evaluation (AME) serve the research community with reliable source for comprehensive information related to the nuclear masses. The next AME version is envisioned to be published at the end of 2016.

  12. 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.

  13. Development of Nuclear Emulsion for Fast Neutron Measurement

    NASA Astrophysics Data System (ADS)

    Machii, Shogo; Kuwabara, Kenichi; Morishima, Kunihiro

    Nuclear emulsion is high sensitive photographic film used for detection of three-dimensional trajectory of charged particles. Energy resolution of nuclear emulsion is 21% (12%) FWHM against neutron energy of 2.8 MeV (4.9 MeV). Nuclear emulsion has high gamma ray rejection power. For now, at least 2×104 gamma rays/cm2, no increase of as a background for neutron measurement when scan using automatic nuclear emulsion read out system HTS. This value suggests that it is applicable even under high gamma ray environment, such as nuclear fusion reactor.

  14. 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…

  15. 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…

  16. Electron-correlation effects in the g factor of light Li-like ions

    NASA Astrophysics Data System (ADS)

    Yerokhin, V. A.; Pachucki, K.; Puchalski, M.; Harman, Z.; Keitel, C. H.

    2017-06-01

    We investigate electron-correlation effects in the g factor of the ground state of Li-like ions. Our calculations are performed within the nonrelativistic quantum electrodynamics (NRQED) expansion up to two leading orders in the fine-structure constant α , α2, and α3. The dependence of the NRQED results on the nuclear charge number Z is studied and the individual 1 /Z -expansion contributions are identified. Combining the obtained data with the results of the all-order (in Z α ) calculations performed within the 1 /Z expansion, we derive unified theoretical predictions for the g factor of light Li-like ions.

  17. Nuclear recoil measurements with the ARIS experiment

    NASA Astrophysics Data System (ADS)

    Fan, Alden; ARIS Collaboration

    2017-01-01

    As direct dark matter searches become increasingly sensitive, it is important to fully characterize the target of the search. The goal of the Argon Recoil Ionization and Scintillation (ARIS) experiment is to quantify information related to the scintillation and ionization energy scale, quenching factor, ion recombination probability, and scintillation time response of nuclear recoils, as expected from WIMPs, in liquid argon. A time projection chamber with an active mass of 0.5 kg of liquid argon and capable of full 3D position reconstruction was exposed to an inverse kinematic neutron beam at the Institut de Physique Nucleaire d'Orsay in France. A scan of nuclear recoil energies was performed through coincidence with a set of neutron detectors to quantify properties of nuclear recoils in liquid argon at various electric fields. The difference in ionization and scintillation response with differing recoil track angle to the electric field was also studied. The preliminary results of the experiment will be presented.

  18. A Measurement Control Program for Nuclear Material Accounting

    SciTech Connect

    Brouns, R. J.; Roberts, F. P.; Merrill, J. A.; Brown, W. B.

    1980-06-01

    A measurement control program for nuclear material accounting monitors and controls the quality of the measurements of special nuclear material that are involved in material balances. The quality is monitored by collecting data from which the current precision and accuracy of measurements can be evaluated. The quality is controlled by evaluations, reviews, and other administrative measures for control of selection or design of facilities. equipment and measurement methods and the training and qualification of personnel who perform SNM measurements. This report describes the most important elements of a program by which management can monitor and control measurement quality.

  19. 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.

  20. Nature of Tunable Hole g Factors in Quantum Dots

    NASA Astrophysics Data System (ADS)

    Ares, N.; Golovach, V. N.; Katsaros, G.; Stoffel, M.; Fournel, F.; Glazman, L. I.; Schmidt, O. G.; De Franceschi, S.

    2013-01-01

    We report an electric-field-induced giant modulation of the hole g factor in SiGe nanocrystals. The observed effect is ascribed to a so-far overlooked contribution to the g factor that stems from the mixing between heavy- and light-hole wave functions. We show that the relative displacement between the confined heavy- and light-hole states, occurring upon application of the electric field, alters their mixing strength leading to a strong nonmonotonic modulation of the g factor.

  1. First-excited state g factor of 136Te by the recoil in vacuum method

    DOE PAGES

    Danchev, M.; Stone, N. J.; Stuchberry, A. E.; ...

    2017-07-01

    The g factor of the first 2+ state of radioactive 136 Te with two valence protons and two valence neutrons beyond double-magic 132Sn has been measured by the recoil in vacuum (RIV) method. The lifetime of this state is an order of magnitude longer than the lifetimes of excited states recently measured by the RIV method in Sn and Te isotopes, requiring a new evaluation of the free-ion hyperfine interactions and methodology used to determine the g factor. The calibration data are reported and the analysis procedures are described in detail. The resultant g factor has a similar magnitude tomore » the g factors of other nuclei with an equal number of valence protons and neutrons in the major shell. However, an unexpected trend is found in the g factors of the N = 84 isotones, which decrease from 136Te to 144Nd. Shell model calculations with interactions derived from the CD Bonn potential show good agreement with the g factors and E2 transition rates of 2+ states around 132Sn, confirming earlier indications that 132Sn is a good doubly magic core.« less

  2. First-excited state g factor of Te136 by the recoil in vacuum method

    DOE PAGES

    Stuchbery, A. E.; Allmond, J. M.; Danchev, M.; ...

    2017-07-27

    The g factor of the first 2+ state of radioactive 136Te with two valence protons and two valence neutrons beyond double-magic 132Sn has been measured by the recoil in vacuum (RIV) method. The lifetime of this state is an order of magnitude longer than the lifetimes of excited states recently measured by the RIV method in Sn and Te isotopes, requiring a new evaluation of the free-ion hyperfine interactions and methodology used to determine the g factor. In this paper, the calibration data are reported and the analysis procedures are described in detail. The resultant g factor has a similarmore » magnitude to the g factors of other nuclei with an equal number of valence protons and neutrons in the major shell. However, an unexpected trend is found in the g factors of the N = 84 isotones, which decrease from 136Te to 144Nd. Finally, shell model calculations with interactions derived from the CD Bonn potential show good agreement with the g factors and E2 transition rates of 2+ states around 132Sn, confirming earlier indications that 132Sn is a good doubly magic core.« less

  3. 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).

  4. First-excited state g factor of 136Te by the recoil in vacuum method

    NASA Astrophysics Data System (ADS)

    Stuchbery, A. E.; Allmond, J. M.; Danchev, M.; Baktash, C.; Bingham, C. R.; Galindo-Uribarri, A.; Radford, D. C.; Stone, N. J.; Yu, C.-H.

    2017-07-01

    The g factor of the first 2+ state of radioactive 136Te with two valence protons and two valence neutrons beyond double-magic 132Sn has been measured by the recoil in vacuum (RIV) method. The lifetime of this state is an order of magnitude longer than the lifetimes of excited states recently measured by the RIV method in Sn and Te isotopes, requiring a new evaluation of the free-ion hyperfine interactions and methodology used to determine the g factor. The calibration data are reported and the analysis procedures are described in detail. The resultant g factor has a similar magnitude to the g factors of other nuclei with an equal number of valence protons and neutrons in the major shell. However, an unexpected trend is found in the g factors of the N =84 isotones, which decrease from 136Te to 144Nd. Shell model calculations with interactions derived from the CD Bonn potential show good agreement with the g factors and E 2 transition rates of 2+ states around 132Sn, confirming earlier indications that 132Sn is a good doubly magic core.

  5. 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.

  6. 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.

  7. Universal behavior of electron g -factors in semiconductor nanostructures

    NASA Astrophysics Data System (ADS)

    Tadjine, Athmane; Niquet, Yann-Michel; Delerue, Christophe

    2017-06-01

    We combine analytic developments and numerical tight-binding calculations to study the evolution of the electron g -factors in homogeneous nanostructures of III-V and II-VI semiconductors. We demonstrate that the g -factor can be always written as a sum of bulk and surface terms. The bulk term, the dominant one, just depends on the energy gap of the nanostructure but is otherwise isotropic and independent of size, shape, and dimensionality. At the same time, the magnetic moment density at the origin of the bulk term is anisotropic and strongly dependents on the nanostructure shape. The physical origin of these seemingly contradictory findings is explained by the relation between the spin-orbit-induced currents and the spatial derivatives of the electron envelope wave function. The tight-binding calculations show that the g -factor versus energy gap for spherical nanocrystals can be used as a reference curve. In quantum wells, nanoplatelets, nanorods, and nanowires, the g -factor along the rotational symmetry axis can be predicted from the reference curve with a good accuracy. The g -factors along nonsymmetric axes exhibit more important deviations due to surface contributions but the energy gap remains the main quantity determining their evolution. The importance of surface-induced anisotropies of the g -factors is discussed.

  8. Self-energy correction to the hyperfine splitting and the electron g factor in hydrogenlike ions

    SciTech Connect

    Yerokhin, Vladimir A.; Jentschura, Ulrich D.

    2010-01-15

    The hyperfine structure (hfs) and the g factor of a bound electron are caused by external magnetic fields. For the hfs, the magnetic field is due to the nuclear spin. A uniform-in-space and constant-in-time magnetic field is used to probe the bound-electron g factor. The self-energy corrections to these effects are more difficult to evaluate than those to the Lamb shift. Here, we describe a numerical approach for both effects in the notoriously problematic regime of hydrogenlike bound systems with low nuclear charge numbers. The calculation is nonperturbative in the binding Coulomb field. Accurate numerical values for the remainder functions are provided for 2P states and for nS states with n=1,2,3.

  9. 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.

  10. Propagation of nuclear data uncertainties for fusion power measurements

    NASA Astrophysics Data System (ADS)

    Sjöstrand, Henrik; Conroy, Sean; Helgesson, Petter; Hernandez, Solis Augusto; Koning, Arjan; Pomp, Stephan; Rochman, Dimitri

    2017-09-01

    Neutron measurements using neutron activation systems are an essential part of the diagnostic system at large fusion machines such as JET and ITER. Nuclear data is used to infer the neutron yield. Consequently, high-quality nuclear data is essential for the proper determination of the neutron yield and fusion power. However, uncertainties due to nuclear data are not fully taken into account in uncertainty analysis for neutron yield calibrations using activation foils. This paper investigates the neutron yield uncertainty due to nuclear data using the so-called Total Monte Carlo Method. The work is performed using a detailed MCNP model of the JET fusion machine; the uncertainties due to the cross-sections and angular distributions in JET structural materials, as well as the activation cross-sections in the activation foils, are analysed. It is found that a significant contribution to the neutron yield uncertainty can come from uncertainties in the nuclear data.

  11. Effective g factor of low-density two-dimensional holes in a Ge quantum well

    DOE PAGES

    Lu, T. M.; Harris, C. T.; Huang, S. -H.; ...

    2017-09-04

    Here we report the measurements of the effective g factor of low-density two-dimensional holes in a Ge quantum well. Using the temperature dependence of the Shubnikov-de Haas oscillations, we extract the effective g factor in a magnetic field perpendicular to the sample surface. Very large values of the effective g factor, ranging from ~13 to ~28, are observed in the density range of 1.4×1010 cm-2– 1.4×1011 cm-2. When the magnetic field is oriented parallel to the sample surface, the effective g factor is obtained from a protrusion in the magneto-resistance data that signify full spin polarization. In the latter orientation,more » a small effective g factor, ~1.3-1.4, is measured in the density range of 1.5×1010 cm-2–2×1010 cm-2. Finally, this very strong anisotropy is consistent with theoretical predictions and previous measurements in other 2D hole systems, such as InGaAs and GaSb.« less

  12. Effective g factor in black phosphorus thin films

    NASA Astrophysics Data System (ADS)

    Zhou, Xiaoying; Lou, Wen-Kai; Zhang, Dong; Cheng, Fang; Zhou, Guanghui; Chang, Kai

    2017-01-01

    We theoretically investigate the effective g factor in the black phosphorus (BP) thin films (TFs) based on a multiband k .p theory. We demonstrate that the effective single particle g factor in pristine BP TF is anisotropic arising from its anisotropic band structure with gxx *≈gyy *≈2.0 and gzz * sensitively depending on the interband coupling and the band gap. The gzz * approaches 2.0 with increasing hole doping density and gate electric field since both of them minish the interband coupling by reducing the overlap integral between the electron and hole wave functions. We also estimate the exchange interaction enhancement on the effective single particle g factor by using the screened Hartree-Fock approximation. The exchange interaction enhanced g factor (gex) shows maxima (minima) at odd (even) filling factors. The effective g factor (g*) oscillates with the increase of magnetic field and sensitively depends on the Landau level broadening as well as the gate electric field since both of them affect the interband coupling and the electron-electron interactions.

  13. Orbital Contributions to the Electron g Factor in Semiconductor Nanowires

    NASA Astrophysics Data System (ADS)

    Winkler, Georg W.; Varjas, Dániel; Skolasinski, Rafal; Soluyanov, Alexey A.; Troyer, Matthias; Wimmer, Michael

    2017-07-01

    Recent experiments on Majorana fermions in semiconductor nanowires [S. M. Albrecht, A. P. Higginbotham, M. Madsen, F. Kuemmeth, T. S. Jespersen, J. Nygård, P. Krogstrup, and C. M. Marcus, Nature (London) 531, 206 (2016), 10.1038/nature17162] revealed a surprisingly large electronic Landé g factor, several times larger than the bulk value—contrary to the expectation that confinement reduces the g factor. Here we assess the role of orbital contributions to the electron g factor in nanowires and quantum dots. We show that an L .S coupling in higher subbands leads to an enhancement of the g factor of an order of magnitude or more for small effective mass semiconductors. We validate our theoretical finding with simulations of InAs and InSb, showing that the effect persists even if cylindrical symmetry is broken. A huge anisotropy of the enhanced g factors under magnetic field rotation allows for a straightforward experimental test of this theory.

  14. Nuclear-Spin Measurements of Quantum Hall Systems

    NASA Astrophysics Data System (ADS)

    Hirayama, Yoshiro

    Nuclear magnetic resonance (NMR) is widely used in the physical, chemical, and biological sciences. However, conventional NMR techniques based on induction-detection have drawbacks of low-sensitivity and the need of a relatively large sample. It is not suitable to investigate single or double layers (or their nanostructure), which is essential in studying quantum Hall (QH) effects. In this presentation, I discussed a resistively-detected technique to overcome the low-sensitivity limitation of conventional NMR and its application to QH systems. Resistively-detected nuclear-spin-based measurements rely on enhanced interactions between electron and nuclear spins at the degenerate point of different electron-spin states. For example, at the ν = 2/3 degenerate point in a AlGaAs/GaAs system,1-3 nuclear-spin polarization far beyond the thermal equilibrium is generated using current flow (dynamic nuclear-spin polarization). Moreover, nuclear-spin polarization can be detected as enhanced resistance, which is proportional to the magnetization, Mz, of nuclear spins.2 It should be stressed that the special states of ν = 2/3 are needed for dynamic nuclear-spin polarization and Mz detection, but we can apply NMR spectrum and nuclear-spin relaxation (T1 time) measurements for any state we want to estimate. These nuclear-spin-based measurements were successfully applied to characterize QH systems, especially their electron-spin features, using single and double layer systems where characteristics are controlled electrically by the gate biases. For a single layer, we could clarify skyrmion,2 spin-polarization of composite fermion,4 and enhanced spin-orbit interactions in a strongly asymmetric confinement.5 Exciting phases, like a canted antiferromagnetic phase, were studied in a double layer QH system with a total filling factor of 2 (Refs. 6, 7). The low-frequency mode was sensitively detected by monitoring T1, reflecting correlated electron spin features.7 The clear

  15. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

    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.

  17. 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.

  18. 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.

  19. 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)

  20. Monitoring the Random Errors of Nuclear Material Measurements

    SciTech Connect

    ,

    1980-06-01

    Monitoring and controlling random errors is an important function of a measurement control program. This report describes the principal sources of random error in the common nuclear material measurement processes and the most important elements of a program for monitoring, evaluating and controlling the random error standard deviations of these processes.

  1. 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.

  2. High resolution image measurements of nuclear tracks

    NASA Technical Reports Server (NTRS)

    Shirk, E. K.; Price, P. B.

    1980-01-01

    The striking clarity and high contrast of the mouths of tracks etched in CR-39 plastic detectors allow automatic measurement of track parameters to be made with simple image-recognition equipment. Using a commercially available Vidicon camera system with a microprocessor-controlled digitizer, resolution for normally incident C-12 and N-14 ions at 32 MeV/amu equivalent to a 14sigma separation of adjacent charges was demonstrated.

  3. Precision Measurement of Nuclear Electron Capture Decay

    NASA Astrophysics Data System (ADS)

    Koltick, David; Liu, Shih-Chieh; Wang, Haoyu; Heim, Jordan; Nistor, Jonathan

    2017-01-01

    The method of accurately measuring the radioactive decay constant of a isotope by measuring the decay rate as a function of time requires that both the detector and environment be stable over time periods comparable to the life-time of the isotope. In addition statistical accuracy requires initial counting rates be high but limited by the dead time capability of the data collection system and the detectors double-event resolving time. A High Purity Germanium (HPGe) spectrometer, sensitive to radiation from 3-KeV to over 3-MeV, has been built to measure radioactive decay constants to a level of 10-5 10-6 at a location only 6 meters from the core of the High Flux Isotope Reactor located at Oak Ridge National Laboratory. Such accuracy requires understanding of, background, signal-processing algorithms, and both the double and triple event pile-up in the observed spectrum. The approach taken is to fit the collected energy spectrum with invariant shapes, independent of event rate. By fixing the source-detector geometry and environmental conditions, the invariant shapes are (1) ideal energy spectrum without pile-up and background, (2) the ideal double event pile-up spectrum, (3) the ideal triple event pile-up spectrum, and (4) the stable background spectrum. A method is presented that finds these ideal shapes using the collected data in situ. Taking this approach the HPGe detector photopeak shape in the absence of background and pile-up is presented showing associated structure over a range of 7 orders of magnitude.

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

    PubMed

    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.

  5. 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.

  6. 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.

  7. Measuring Nuclear Effects with MINERvA

    NASA Astrophysics Data System (ADS)

    Felix, Julian; Minerva Collaboration

    2011-04-01

    The MINERνA Detector (http://minerva.fnal.gov) (Main INjector ExpeRiment νA) is a high statistics experiment in a NuMI beamline at Fermilab. Its main goals are to measure the interactions neutrino (antineutrino)-Nucleus at low energies in order to improve neutrino oscillation studies and study the dynamics between neutrinos (antineutrino) and nucleons within nuclei. The detector is installed and collecting data. For calibration, the MINERνA collaboration created the MINERνA Test Beam experiment. This was designed, constructed and commissioned successfully. In Summer of 2010, it finished its first data run; analyses are in progress. This talk will report on the data that was taken and the suite of analyses that are underway. Fermilab Collaboration

  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. Liquid level measurement in high level nuclear waste slurries

    SciTech Connect

    Weeks, G.E.; Heckendorn, F.M.; Postles, R.L.

    1990-01-01

    Accurate liquid level measurement has been a difficult problem to solve for the Defense Waste Processing Facility (DWPF). The nuclear waste sludge tends to plug or degrade most commercially available liquid-level measurement sensors. A liquid-level measurement system that meets demanding accuracy requirements for the DWPF has been developed. The system uses a pneumatic 1:1 pressure repeater as a sensor and a computerized error correction system. 2 figs.

  10. Measurements of nitric oxide after a nuclear burst

    NASA Technical Reports Server (NTRS)

    Mcghan, M.; Shaw, A.; Megill, L. R.; Sedlacek, W.; Guthals, P. R.; Fowler, M. M.

    1981-01-01

    Measurements of ozone and nitric oxide in a nuclear cloud 7 days after the explosion are reported. No measurable increase above ambient density of either ozone or nitric oxide was found. Results from a chemistry model of the cloud do not agree with the measurement unless 'nonstandard' assumptions are made with regard to the operating chemical processes. A number of possible explanations of the results are discussed.

  11. Predicted Landé g-factors for open shell diatomic molecules

    NASA Astrophysics Data System (ADS)

    Semenov, Mikhail; Yurchenko, Sergei. N.; Tennyson, Jonathan

    2016-12-01

    The program DUO (Yurchenko et al., 2016) provides direct solutions of the nuclear motion Schrödinger equation for the (coupled) potential energy curves of open shell diatomic molecules. Wavefunctions from DUO are used to compute Landé g-factors valid for weak magnetic fields; the results are compared with the idealized predictions of both Hund's case (a) and Hund's case (b) coupling schemes. Test calculations are performed for AlO, NO, CrH and C2. The computed gJ 's both provide a sensitive test of the underlying spectroscopic model used to represent the system and an indication of whether states of the molecule are well-represented by the either of the Hund's cases considered. The computation of Landé g-factors is implemented as a standard option in the latest release of DUO.

  12. 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…

  13. 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…

  14. 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.

  15. 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

  16. Surveying Temperature and Density Measurements in Nuclear Calorimetry

    NASA Astrophysics Data System (ADS)

    Raciti, G.; Bassini, R.; Begemann-Blaich, M.; Fritz, S.; Groß, C.; Immè, G.; Iori, I.; Lynen, U.; Mahi, M.; Möhlenkamp, T.; Müller, W. F. J.; Ocker, B.; Odeh, T.; Pochodzalla, J.; Riccobene, G.; Romano, F. P.; Saija, A.; Schwarz, C.; Serfling, V.; Schnittker, M.; Schüttauf, A.; Seidel, W.; Sfienti, C.; Trautmann, W.; Trzclnski, A.; Verde, G.; Xi, Hongfei; Zwieglinski, B.

    2001-11-01

    An experimental investigation on thermodynamical observables characterizing the conditions of multifragmenting systems is reported. High granularity hodoscopes allowed simultaneous measurements of isotopic and emission temperatures. HBT interferometry with light charged particles allowed radii measurements. The disagreement between the two temperature measurements could be related to the space-time evolution of the fragmentation process as confirmed by density measurements. The slope temperatures derived from the target spectator decay fragment energy spectra suggest a dependence on the Fermi motion within the initial system. The dependence of the Nuclear Caloric Curve on the mass of the systems was probed.

  17. Nuclear fragmentation measurements for hadrontherapy and space radiation protection

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

    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 12C 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.

  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. A nuclear data approach for the Hubble constant measurements

    NASA Astrophysics Data System (ADS)

    Pritychenko, Boris

    2017-09-01

    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 67.2(69) (km/sec)/Mpc. This recommended value is based on the last 20 years of experimental research and includes contributions from different types of measurements. The present result implies (14.55 ± 1.51) × 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.

  20. 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.

  1. Nuclear astrophysics measurements with ELISSA at ELI-NP

    NASA Astrophysics Data System (ADS)

    Matei, C.; Balabanski, D. L.; Tesileanu, O.; Xu, Y.; La Cognata, M.; Spitaleri, C.

    2017-09-01

    ELISSA is a new silicon-strip detector array under development at the Extreme Light Infrastructure - Nuclear Physics facility in collaboration with INFN-LNS, Catania. ELI-NP will provide very intense, brilliant gamma beams, tunable from 200keV to 19.5MeV. Several reactions important for the astrophysical p-process, Big Bang Nucleosynthesis and supernova explosion have been selected for the first measurement campaigns starting in 2019.

  2. 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.

  3. 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.

  4. 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.

  5. Problems in detection and measurement in nuclear medicine

    NASA Astrophysics Data System (ADS)

    Aysun Ugur, Fatma

    2015-07-01

    Nuclear Medicine studies are performed with a variety of types of radiation measurement instruments, depending on the kind of radiation source that is being measured and the type of information sought. For example, some instruments are designed for in vitro measurements on blood samples, urine specimens, and so forth. Others are designed for in vivo measurements of radioactivity in patients. All these instruments have special design characteristics to optimize them for their specific tasks, as described in this study; however, some considerations of design characteristics and performance limitations are common to all of them. An important consideration for any radiation measurement instrument is its detection efficiency. Maximum detection efficiency is desirable because one thus obtains maximum information with a minimum amount of radioactivity. Also important are instrument's counting rate limitations. There are finite counting rate limits for all counting and imaging instruments used in nuclear medicine, above which accurate results are obtained because of data losses and other data distortions. Non penetrating radiations, such as ß particles, have special detection and measurement problems. In this study, some of these general considerations have been discussed.

  6. Dispersion of the electron g factor anisotropy in InAs/InP self-assembled quantum dots

    SciTech Connect

    Belykh, V. V.; Yakovlev, D. R.; Bayer, M.; Schindler, J. J.; Bree, J. van; Koenraad, P. M.; Silov, A. Yu.; Averkiev, N. S.

    2016-08-28

    The electron g factor in an ensemble of InAs/InP quantum dots with emission wavelengths around 1.4 μm is measured using time-resolved pump-probe Faraday rotation spectroscopy in different magnetic field orientations. Thereby, we can extend recent single dot photoluminescence measurements significantly towards lower optical transition energies through 0.86 eV. This allows us to obtain detailed insight into the dispersion of the recently discovered g factor anisotropy in these infrared emitting quantum dots. We find with decreasing transition energy over a range of 50 meV a strong enhancement of the g factor difference between magnetic field normal and along the dot growth axis, namely, from 1 to 1.7. We argue that the g factor cannot be solely determined by the confinement energy, but the dot asymmetry underlying this anisotropy therefore has to increase with increasing dot size.

  7. Dispersion of the electron g factor anisotropy in InAs/InP self-assembled quantum dots

    NASA Astrophysics Data System (ADS)

    Belykh, V. V.; Yakovlev, D. R.; Schindler, J. J.; van Bree, J.; Koenraad, P. M.; Averkiev, N. S.; Bayer, M.; Silov, A. Yu.

    2016-08-01

    The electron g factor in an ensemble of InAs/InP quantum dots with emission wavelengths around 1.4 μm is measured using time-resolved pump-probe Faraday rotation spectroscopy in different magnetic field orientations. Thereby, we can extend recent single dot photoluminescence measurements significantly towards lower optical transition energies through 0.86 eV. This allows us to obtain detailed insight into the dispersion of the recently discovered g factor anisotropy in these infrared emitting quantum dots. We find with decreasing transition energy over a range of 50 meV a strong enhancement of the g factor difference between magnetic field normal and along the dot growth axis, namely, from 1 to 1.7. We argue that the g factor cannot be solely determined by the confinement energy, but the dot asymmetry underlying this anisotropy therefore has to increase with increasing dot size.

  8. Electron g-factor for cubic Zn1-xCdxSe determined by spin-flip Raman scattering

    NASA Astrophysics Data System (ADS)

    Karimov, O. Z.; Wolverson, D.; Davies, J. J.; Stepanov, S. I.; Ruf, T.; Ivanov, S. V.; Sorokin, S. V.; O'donnell, C. B.; Prior, K. A.

    2000-12-01

    We present spin-flip Raman-scattering measurements of the g-factor for electrons bound at neutral donors in cubic Zn1-xCdxSe (0<=x<=1) grown by molecular-beam epitaxy. Excitation in resonance with the donor-bound exciton luminescence transition in the presence of a magnetic field produces Raman signals associated with transitions between the spin states of the bound electron. The dependence of the Raman shift of the signals on the magnetic field allows an accurate determination of the electron g-factor. For the particular case of cubic CdSe, the g-factor was measured to be +0.42+/-0.01. Five-band k.p perturbation theory was successfully used to reproduce the experimental dependence of the g-factor on Cd content, which can be approximated well by g(x)=1.16-0.56x-0.18x2.

  9. 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.

  10. 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.

  11. 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.

  12. Charged fusion product loss measurements using nuclear activation

    SciTech Connect

    Bonheure, G.; Hult, M.; Gonzalez de Orduna, R.; Wieslander, E.; Arnold, D.; Dombrowski, H.; Laubenstein, M.; Murari, A.; Collaboration: JET-EFDA Contributors

    2010-10-15

    In ITER, {alpha} 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.

  13. 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.

  14. QED theory of the nuclear magnetic shielding in hydrogenlike ions.

    PubMed

    Yerokhin, V A; Pachucki, K; Harman, Z; Keitel, C H

    2011-07-22

    The shielding of the nuclear magnetic moment by the bound electron in hydrogenlike ions is calculated ab initio with inclusion of relativistic, nuclear, and quantum electrodynamics (QED) effects. The QED correction is evaluated to all orders in the nuclear binding strength parameter and, independently, to the first order in the expansion in this parameter. The results obtained lay the basis for the high-precision determination of nuclear magnetic dipole moments from measurements of the g factor of hydrogenlike ions.

  15. Measuring the Nuclear Levels in 19Ne using GODDESS

    NASA Astrophysics Data System (ADS)

    Hall, Matthew; Experiment 1488 Collaboration Collaboration

    2016-09-01

    A direct way to test nova explosion models is to observe gamma rays created in the decay of radioactive isotopes produced in the nova. One such isotope, 18F, is believed to be the main source of observable 511-keV gamma rays. The main destruction mechanism of 18F is thought to be the 18F(p,α)15O reaction, and the uncertainty in the reaction rate is attributed to uncertainties in the energies, spins, and parities of the nuclear levels in 19Ne above the proton threshold. A 3He beam was used at Argonne National Lab in an effort to understand the levels in 19Ne via the 19F(3He,t)19Ne reaction. Gammasphere ORRUBA Dual Detectors for Experimental Structure Studies (GODDESS) was used to measure gamma rays from the decay of 19Ne in coincidence with the reaction tritons. Preliminary data from the experiment will be presented. This research was supported by the National Science Foundation, the US DOE Office of Nuclear Physics and the National Nuclear Security Administration.

  16. 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…

  17. 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…

  18. 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.

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

    NASA Astrophysics Data System (ADS)

    Hardy, J. C.

    2012-11-01

    For 60 years, superallowed 0+→0+ 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 10C to 74Rb. 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, GV, has been extracted from the data and used to determine the top left element of the CKM matrix, Vud. 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.

  20. 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.

  1. Lifetime Measurement of the 229Th nuclear isomer

    NASA Astrophysics Data System (ADS)

    Seiferle, Benedict; von der Wense, Lars; Thirolf, Peter G.

    2017-01-01

    The first excited isomeric state of 229Th possesses the lowest energy among all known excited nuclear states. The expected energy is accessible with today's laser technology and in principle allows for a direct optical laser excitation of the nucleus. The isomer decays via three channels to its ground state (internal conversion, γ decay, and bound internal conversion), whose strengths depend on the charge state of Thm229 . We report on the measurement of the internal-conversion decay half-life of neutral Thm229 . A half-life of 7 ±1 μ s has been measured, which is in the range of theoretical predictions and, based on the theoretically expected lifetime of ≈1 04 s of the photonic decay channel, gives further support for an internal conversion coefficient of ≈1 09, thus constraining the strength of a radiative branch in the presence of internal conversion.

  2. MicroRaman measurements for nuclear fuel reprocessing applications

    DOE PAGES

    Casella, Amanda; Lines, Amanda; Nelson, Gilbert; ...

    2016-12-01

    Treatment and reuse of used nuclear fuel is a key component in closing the nuclear fuel cycle. Solvent extraction reprocessing methods that have been developed contain various steps tailored to the separation of specific radionuclides, which are highly dependent upon solution properties. The instrumentation used to monitor these processes must be robust, require little or no maintenance, and be able to withstand harsh environments such as high radiation fields and aggressive chemical matrices. Our group has been investigating the use of optical spectroscopy for the on-line monitoring of actinides, lanthanides, and acid strength within fuel reprocessing streams. This paper willmore » focus on the development and application of a new MicroRaman probe for on-line real-time monitoring of the U(VI)/nitrate ion/nitric acid in solutions relevant to used nuclear fuel reprocessing. Previous research has successfully demonstrated the applicability on the macroscopic scale, using sample probes requiring larger solution volumes. In an effort to minimize waste and reduce dose to personnel, we have modified this technique to allow measurement at the microfluidic scale using a Raman microprobe. Under the current sampling environment, Raman samples typically require upwards of 10 mL and larger. Using the new sampling system, we can sample volumes at 10 μL or less, which is a scale reduction of over 1,000 fold in sample size. Finally, this paper will summarize our current work in this area including: comparisons between the macroscopic and microscopic probes for detection limits, optimized channel focusing, and application in a flow cell with varying levels of HNO3, and UO2(NO3)2.« less

  3. MicroRaman measurements for nuclear fuel reprocessing applications

    SciTech Connect

    Casella, Amanda; Lines, Amanda; Nelson, Gilbert; Bello, Job; Bryan, Samuel

    2016-12-01

    Treatment and reuse of used nuclear fuel is a key component in closing the nuclear fuel cycle. Solvent extraction reprocessing methods that have been developed contain various steps tailored to the separation of specific radionuclides, which are highly dependent upon solution properties. The instrumentation used to monitor these processes must be robust, require little or no maintenance, and be able to withstand harsh environments such as high radiation fields and aggressive chemical matrices. Our group has been investigating the use of optical spectroscopy for the on-line monitoring of actinides, lanthanides, and acid strength within fuel reprocessing streams. This paper will focus on the development and application of a new MicroRaman probe for on-line real-time monitoring of the U(VI)/nitrate ion/nitric acid in solutions relevant to used nuclear fuel reprocessing. Previous research has successfully demonstrated the applicability on the macroscopic scale, using sample probes requiring larger solution volumes. In an effort to minimize waste and reduce dose to personnel, we have modified this technique to allow measurement at the microfluidic scale using a Raman microprobe. Under the current sampling environment, Raman samples typically require upwards of 10 mL and larger. Using the new sampling system, we can sample volumes at 10 μL or less, which is a scale reduction of over 1,000 fold in sample size. Finally, this paper will summarize our current work in this area including: comparisons between the macroscopic and microscopic probes for detection limits, optimized channel focusing, and application in a flow cell with varying levels of HNO3, and UO2(NO3)2.

  4. MicroRaman Measurements for Nuclear Fuel Reprocessing Applications

    SciTech Connect

    Casella, Amanda; Lines, Amanda; Nelson, Gilbert; Bello, Job; Bryan, Samuel

    2016-01-01

    Treatment and reuse of used nuclear fuel is a key component in closing the nuclear fuel cycle. Solvent extraction reprocessing methods that have been developed contain various steps tailored to the separation of specific radionuclides, which are highly dependent upon solution properties. The instrumentation used to monitor these processes must be robust, require little or no maintenance, and be able to withstand harsh environments such as high radiation fields and aggressive chemical matrices. Our group has been investigating the use of optical spectroscopy for the on-line monitoring of actinides, lanthanides, and acid strength within fuel reprocessing streams. This paper will focus on the development and application of a new MicroRaman probe for on-line real-time monitoring of the U(VI)/nitrate ion/nitric acid in solutions relevant to used nuclear fuel reprocessing. Previous research has successfully demonstrated the applicability on the macroscopic scale, using sample probes requiring larger solution volumes. In an effort to minimize waste and reduce dose to personnel, we have modified this technique to allow measurement at the microfluidic scale using a Raman microprobe. Under the current sampling environment, Raman samples typically require upwards of 10 mL and larger. Using the new sampling system, we can sample volumes at 10 μL or less, which is a scale reduction of over 1,000 fold in sample size. This paper will summarize our current work in this area including: comparisons between the macroscopic and microscopic probes for detection limits, optimized channel focusing, and application in a flow cell with varying levels of HNO3, and UO2(NO3)2.

  5. 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

    ... 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 period... Measures for Nuclear Power Plant Fire Protection (CARMEN-FIRE).'' In response to comments from members...

  6. Measurement of Vud with 0+→0+ nuclear beta decays

    NASA Astrophysics Data System (ADS)

    Hardy, J. C.; Towner, I. S.

    2013-10-01

    Results from superallowed 0+→0+ nuclear beta decays today provide the best value for Vud, with an uncertainty of ±0.02%. Some 150 independent measurements of 13 separate superallowed transitions covering a wide range of parent nuclei from 10C to 74Rb constitute a very robust data set. Excellent consistency among the average results for all 13 transitions - an expected consequence of the conservation of vector current (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, GV, has been extracted from the data and used to determine |Vud| = 0.97425 (22).

  7. Nuclear radiation-warning detector that measures impedance

    DOEpatents

    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.

  8. 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.

  9. 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

  10. 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

  11. Nanoscale measurements of proton tracks using fluorescent nuclear track detectors

    SciTech Connect

    Sawakuchi, Gabriel O. Sahoo, Narayan; Ferreira, Felisberto A.; McFadden, Conor H.; Hallacy, Timothy M.; Granville, Dal A.; Akselrod, Mark S.

    2016-05-15

    Purpose: The authors describe a method in which fluorescence nuclear track detectors (FNTDs), novel track detectors with nanoscale spatial resolution, are used to determine the linear energy transfer (LET) of individual proton tracks from proton therapy beams by allowing visualization and 3D reconstruction of such tracks. Methods: FNTDs were exposed to proton therapy beams with nominal energies ranging from 100 to 250 MeV. Proton track images were then recorded by confocal microscopy of the FNTDs. Proton tracks in the FNTD images were fit by using a Gaussian function to extract fluorescence amplitudes. Histograms of fluorescence amplitudes were then compared with LET spectra. Results: The authors successfully used FNTDs to register individual proton tracks from high-energy proton therapy beams, allowing reconstruction of 3D images of proton tracks along with delta rays. The track amplitudes from FNTDs could be used to parameterize LET spectra, allowing the LET of individual proton tracks from therapeutic proton beams to be determined. Conclusions: FNTDs can be used to directly visualize proton tracks and their delta rays at the nanoscale level. Because the track intensities in the FNTDs correlate with LET, they could be used further to measure LET of individual proton tracks. This method may be useful for measuring nanoscale radiation quantities and for measuring the LET of individual proton tracks in radiation biology experiments.

  12. 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.

  13. Distinguishing Carbonate Reservoir Pore Facies with Nuclear Magnetic Resonance Measurements

    SciTech Connect

    Genty, Coralie; Jensen, Jerry L. Ahr, Wayne M.

    2007-03-15

    Characterization of carbonate rocks may involve identifying the important pore types which are present. In the past, this task has required detailed petrographic analysis of many core samples. Here, we describe a method which uses nuclear magnetic resonance (NMR) measurements to reduce the amount of petrographic analysis needed for porosity typing of carbonate reservoir rocks.For a rock sample which has been measured with NMR, our method decomposes the log(T{sub 2}) spectrum into at most three Gaussian-shaped components and gives a set of nine parameters. Two characteristic quantities having geological significance are extracted from the nine parameters. Values of the two quantities are compared with a reference set, established from samples having both NMR and petrographic evaluations of porosity types. We use a Bayesian approach to the classification of the dominant porosity type.Tests of our method on 103 samples show a correct prediction in 60 to 90 percent of the samples. The lower success rate was obtained for samples with five porosity types from three fields; the higher success rate obtained with samples with three porosity types from one well. The use of geologically significant quantities extracted from the decomposition gives comparable success rate to those obtained using a standard, non-geological approach such as canonical variates.

  14. 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.

  15. g factor of the J/sup. pi. / = 25/2/sup +/ isomer in /sup 205/Tl and the anomalous orbital magnetism of the proton

    SciTech Connect

    Maier, K.H.; Becker, J.A.; Carlson, J.B.; Lanier, R.G.; Mann, L.G.; Struble, G.L.; Nail, T.; Sheline, R.K.; Stoeffl, W.; Ussery, L.

    1982-02-15

    The nuclear gyromagnetic ratio of the 3291-keV J/sup ..pi../ = 25/2/sup +/ /sup 205/Tl level has been measured with use of ..gamma..-ray perturbed angular distribution techniques with the result g = 0.544 +- 0.008. The state was populated with the reaction /sup 204/Hg(t,2n)/sup 205/Tl. With use of the known quantities g(/sup 206/Pb 7/sup -/; E/sub x/ = 2200 keV) and g(/sup 209/Bi 9/2/sup +/; E/sub x/ = 0 keV) the proton orbital magnetic g factor for the 1h orbital was deduced to be g/sub 1/ = 1.115 +- 0.02. This result has been corrected for wave-function admixtures and core polarization effects.

  16. Precise determination of atomic g-factor ratios from a dual isotope magneto-optical trap

    SciTech Connect

    Chan, I.; Barrett, B.; Kumarakrishnan, A.

    2011-09-15

    We demonstrate a technique, for carrying out precise measurements of atomic g-factor ratios, which relies on measurements of Larmor oscillations from coherences between magnetic sublevels in the ground states of {sup 85}Rb and {sup 87}Rb atoms confined in a dual isotope magneto-optical trap. We show that a measurement of g{sub F}{sup (87)}/g{sub F}{sup (85)} with a resolution of 0.69 parts per 10{sup 6} is possible by recording the ratio of Larmor frequencies in the presence of a constant magnetic field. This represents the most precise single measurement of g{sub F}{sup (87)}/g{sub F}{sup (85)} without correcting for systematic effects.

  17. 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.

  18. International guidance on the establishment of quality assurance programmes for radioactivity measurement in nuclear medicine.

    PubMed

    Zimmerman, B E; Herbst, C; Norenberg, J P; Woods, M J

    2006-01-01

    A new guidance document for the implementation of quality assurance (QA) programmes for nuclear medicine radioactivity measurement, produced by the International Atomic Energy Agency, is described. The proposed programme is based on the principles of ISO 17025 and will enable laboratories, particularly in developing countries, to provide consistent, safe and effective radioactivity measurement services to the nuclear medicine community.

  19. Nuclear matrix elements from direct lifetime or cross-section measurements

    SciTech Connect

    Werner, V.; Cooper, N.; Hinton, M.; Ilie, G.; Radeck, D.

    2012-11-20

    The method of simultaneous lifetime and g factor measurements using a plunger device and the RDDS and TDRIV techniques is introduced. Results on lifetimes and hyperfine-interaction parameters for 2{sup +}{sub 1} states in {sup 104-108}Pd, {sup 96,98,104}Ru, and {sup 92,94}Zr, using a plunger device. Another method to obtain electromagnetic matrix elements is direct cross section measurements using NRF. The method is outlined, and some recent results on {sup 76}Se are shown.

  20. Strain-induced g -factor tuning in single InGaAs/GaAs quantum dots

    NASA Astrophysics Data System (ADS)

    Tholen, H. M. G. A.; Wildmann, J. S.; Rastelli, A.; Trotta, R.; Pryor, C. E.; Zallo, E.; Schmidt, O. G.; Koenraad, P. M.; Silov, A. Yu.

    2016-12-01

    The tunability of the exciton g factor in InGaAs quantum dots using compressive biaxial stress applied by piezoelectric actuators is investigated. We find a clear relation between the exciton g factor and the applied stress. A linear decrease of the g factor with compressive biaxial strain is observed consistently in all investigated dots. A connection is established between the response of the exciton g factor to the voltage applied to the piezoelectric actuator and the response of the quantum dot emission energy. We employ a numerical model based on eight-band k .p theory to calculate the exciton g factor of a typical dot as a function of strain and a good agreement with our experiments is found. Our calculations reveal that the change in exciton g factor is dominated by the contribution of the valence band and originates from increased heavy hole light hole splitting when applying external stress.

  1. Improved measurement of parity nonconservation in atomic cesium and first measurement of the nuclear anapole moment

    NASA Astrophysics Data System (ADS)

    Wood, Chris

    1998-05-01

    Historically, atomic parity nonconservation (PNC) measurements have bridged the gap between high energy and low energy physics. Our recently completed 0.35% measurement of PNC in cesium(C. S. Wood et al., Science) 275, 1759 (1997) has gone a step further and created a bridge between atomic physics and nuclear physics. This measurement represents the best low energy test of electroweak unification and, in addition, we have made a 14% measurement of the parity violating nuclear anapole moment(V.V. Flambaum et al., Phys. Lett. B) 146, 367 (1984). Cesium continues to hold a special place for atomic PNC measurements due to the accuracy (1%) with which the necessary atomic structure calculations can be made(S.A. Blundell, J. Sapirstein, and W. R. Johnson, Phys. Rev. D) 45, 1602 (1992); V.A. Dzuba, V. V. Flambaum, and O. P. Sushkov, Phys. Lett. A 141, 147 (1989)., and our result has motivated new calculations. The experiment uses a Stark interference technique to measure PNC, and has achieved a factor of seven improvement over our previous result. Two frequency-stabilized diode lasers are used to optically pump an intense cesium beam, while a third is used for detection and a fourth is used to monitor the spin polarization of the atomic beam using stimulated Raman transitions. A dye laser operating at 540nm, phase locked to a finesse 100,000 power buildup cavity, is used to excite the forbidden 6S-7S transition in a region of crossed electric and magnetic fields. These fields serve to define an experimental coordinate system. We have developed 5 different ways to parity transform this coordinate system, which are crucial to our ability to suppress systematic errors. Our signal is the interference of an allowed 6S-7S transition amplitude with the PNC transition amplitude, which causes a tiny (6 ppm) fractional modulation of the 6S-7S excitation rate synchronous with all 5 parity transformations.

  2. Pipken Award: Nuclear physics mysteries revealed by precision ion trap measurements

    NASA Astrophysics Data System (ADS)

    Dilling, Jens

    2017-01-01

    Nuclear Physics is a fundamental science discipline for over 100 years, and started with precision measurements by Rutherford. Much has been learned and understood in the meantime, but some questions remain and also new nuclear phenomena have been discovered. Precision experiments open new venue to address these. Ion trap technologies, originally conceived for atomic and molecular physics have been adapted to the specific requirements stemming from nuclear physics, for example, to couple ion traps to accelerators and achieve very high speed and efficiencies. In this talk I will show some recent examples and technical developments pertaining to nuclear physics questions and phenomena and how they are addressed with precision ion trap measurements.

  3. 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.

  4. Mechanisms for Strong Anisotropy of In-Plane g -Factors in Hole Based Quantum Point Contacts

    NASA Astrophysics Data System (ADS)

    Miserev, D. S.; Srinivasan, A.; Tkachenko, O. A.; Tkachenko, V. A.; Farrer, I.; Ritchie, D. A.; Hamilton, A. R.; Sushkov, O. P.

    2017-09-01

    In-plane hole g factors measured in quantum point contacts based on p -type heterostructures strongly depend on the orientation of the magnetic field with respect to the electric current. This effect, first reported a decade ago and confirmed in a number of publications, has remained an open problem. In this work, we present systematic experimental studies to disentangle different mechanisms contributing to the effect and develop the theory which describes it successfully. We show that there is a new mechanism for the anisotropy related to the existence of an additional B+k-4σ+ effective Zeeman interaction for holes, which is kinematically different from the standard single Zeeman term B-k-2σ+ considered until now.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Measurement of nuclear effects in neutrino interactions with minimal dependence on neutrino energy

    NASA Astrophysics Data System (ADS)

    Lu, X.-G.; Pickering, L.; Dolan, S.; Barr, G.; Coplowe, D.; Uchida, Y.; Wark, D.; Wascko, M. O.; Weber, A.; Yuan, T.

    2016-07-01

    We present a phenomenological study of nuclear effects in neutrino charged-current interactions, using transverse kinematic imbalances in exclusive measurements. Novel observables with minimal dependence on neutrino energy are proposed to study quasielastic scattering and especially resonance production. They should be able to provide direct constraints on nuclear effects in neutrino- and antineutrino-nucleus interactions.

  10. Comparison of the activity measurements in nuclear medicine services in the Brazilian northeast region.

    PubMed

    de Farias Fragoso, Maria da Conceição; de Albuquerque, Antônio Morais; de Oliveira, Mércia L; de Lima, Fabiana Farias; Barreto, Flávio Chiappetta Paes; de Andrade Lima, Ricardo

    2013-12-01

    The Northeastern Regional Centre for Nuclear Sciences (CRCN-NE), National Nuclear Energy Commission, has organized for the first time in nuclear medicine services (NMSs) in the Brazilian northeast region a comparison of activity measurements for (99m)Tc, (131)I, (67)Ga, (201)Tl and (57)Co. This tool is widely utilized to evaluate not only the accuracy of radionuclide calibrators, but also the competence of NMSs to measure the activity of the radiopharmaceuticals and the performance of the personnel involved in these measurements. The comparison results showed that 90% of the results received from participants are within the ±10% limit established by the Brazilian Norm.

  11. Measurement of the excited-state transverse hyperfine coupling in NV centers via dynamic nuclear polarization

    NASA Astrophysics Data System (ADS)

    Poggiali, F.; Cappellaro, P.; Fabbri, N.

    2017-05-01

    Precise knowledge of a quantum system's Hamiltonian is a critical pre-requisite for its use in many quantum information technologies. Here, we report a method for the precise characterization of the nonsecular part of the excited-state Hamiltonian of an electronic-nuclear spin system in diamond. The method relies on the investigation of the dynamic nuclear polarization mediated by the electronic spin, which is currently exploited as a primary tool for initializing nuclear qubits and performing enhanced nuclear magnetic resonance. By measuring the temporal evolution of the population of the ground-state hyperfine levels of a nitrogen-vacancy center, we obtain the first direct estimation of the excited-state transverse hyperfine coupling between its electronic and nitrogen nuclear spin. Our method could also be applied to other electron-nuclear spin systems, such as those related to defects in silicon carbide.

  12. Giant M 1 resonance in sup 120 Sn and the quenching of the nucleon spin g factors

    SciTech Connect

    Alarcon, R.; Laszewski, R.M.; Dale, D.S. )

    1989-09-01

    The distribution of magnetic dipole transition strength in {sup 120}Sn has been measured at excitations between 7.3 and 9.3 MeV using highly polarized tagged photons. A total {ital M}1 strength of {Sigma} eV corresponding to {ital B}({ital M}1{up arrow})=8.8{sub {minus}0.9}{sup +1.1}{mu}{sub 0}{sup 2} {ital was found to be more or less uniformly distributed throughout the region}. {ital This result and previous polarized photon measurements in} {sup 90}Zr and the Pb nuclei present a consistent picture of {ital M}1 strengths in closed-shell nuclei in terms of the required normalization for the spin nucleon {ital g} factors. Normalizations with respect to the bare nucleon values are 0.68{plus minus}0.02 and 0.64{plus minus}0.03 for the proton and neutron spin {ital g} factors, respectively.

  13. 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

  14. Nuclear Emulsion Measurements of the Astronauts’ Radiation Exposures on Skylab Missions 2, 3 and 4,

    DTIC Science & Technology

    1975-12-10

    AD-AO19 804 NUCLEAR EMULSION MEASUREMENTS OF THE ASTRONAUTS’ RADIATION EXPOSURES ON SKYLAB MISSIONS 2, 3 AND 4 Hermann J. Schaefer, et al Naval...N/A NUCLEAR EMULSION MEASUREMENTS OF THE ASTRONAUTS’ RADIATION EXPOSURES ON SKYLAB MISSIONS 2, 3, AND 4. N/ ___ _ _ ANZ Hermann J. Schaefer and...corresponding shield distribution of the entire vehicle tesi alirections ofetionable whether the very large effort involved in this eask isd• ~~really

  15. Determination of hole g-factor in InAs/InGaAs/InAlAs quantum wells by magneto-photoluminescence studies

    NASA Astrophysics Data System (ADS)

    Terent'ev, Ya. V.; Danilov, S. N.; Durnev, M. V.; Loher, J.; Schuh, D.; Bougeard, D.; Ivanov, S. V.; Ganichev, S. D.

    2017-02-01

    A circularly polarized magneto-photoluminescence (magneto-PL) technique has been applied to investigate the Zeeman effect in InAs/InGaAs/InAlAs quantum wells (QWs) in the Faraday geometry. Structures with different thicknesses of the QW barriers have been studied in the magnetic field parallel and tilted with respect to the sample normal. The effective electron-hole g-factor has been found by measurement of splitting of polarized magneto-PL lines. Landé factors of electrons have been calculated using the 14-band k . p method, and the g-factor of holes was determined by subtracting the calculated contribution of the electrons from the effective electron-hole g-factor. Anisotropy of the hole g-factor has been studied applying the tilted magnetic field.

  16. 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.

  17. 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.

  18. 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.

  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. Relativistic configuration interaction plus linearized-coupled-cluster calculations of U2 + energies, g factors, transition rates, and lifetimes

    NASA Astrophysics Data System (ADS)

    Savukov, I.; Safronova, U. I.; Safronova, M. S.

    2015-11-01

    Excitation energies, term designations, g factors, transition rates, and lifetimes of U2 + are determined using a relativistic configuration interaction (CI) + linearized-coupled-cluster (LCC) approach. The CI-LCC 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 has been found within the 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 multivalence atoms and ions, which would be of interest to many applications.

  1. 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.

  2. Determination of nuclear fuel burn-up axial profile by neutron emission measurement

    NASA Astrophysics Data System (ADS)

    Prokopowicz, Rafal; Pytel, Krzysztof

    2016-12-01

    Burning-up of nuclear fuel is usually not a space-isotropic phenomenon. It depends on both the neutron flux density and energy spectrum distribution during fuel operation in a nuclear reactor. This paper presents the method of measurement of burn-up spatial distribution of spent nuclear fuel element. The method is based on recording of the neutron emission from investigated fuel element. Based on performed analyses and calculations, a suitable measuring setup has been designed and constructed. The subjects of investigation were fuel elements used in the MARIA research reactor, operated by National Centre for Nuclear Research in Świerk, Poland. The results of measurements made over a period of several years by means of the described method are presented in the paper.

  3. Investigations of the EPR g Factors for Er3+ in CaMoO4

    NASA Astrophysics Data System (ADS)

    Wu, Shao-Yi; Dong, Hui-Ning

    2004-06-01

    The electron paramagnetic resonance (EPR) g factors g‖ and g⊥ for Er3+ in CaMoO4 are theoretically investigated by using the perturbation formulas of the g factors for a 4f11 ion in tetragonal symmetry. In these formulas, the contributions to the g factors arising from the second-order perturbation terms and the admixture of various states are considered. The crystal-field parameters for the tetragonally distorted tetrahedra are determined by using the superposition model and the structural data of the impurity Er3+ on the host Ca2+ site in CaMoO4. The calculated g factors agree with the observed values. The validity of the results is discussed.

  4. 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.

  5. 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.

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

    DOE PAGES

    Almaraz-Calderon, S.; Carnelli, P. F. F.; Rehm, K. E.; ...

    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.

  7. 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.

  8. 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.

  9. 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.

  10. Alpha spectrometry — A tool for nuclear data measurements

    NASA Astrophysics Data System (ADS)

    Wiltshire, R. A. P.

    1984-06-01

    Alpha spectrometry is a precise technique which can be applied to the measurement of data such as half-lives and the production cross-sections of higher actinides. The application of this technique to the measurement of 239Pu and 242Cm half-lives, to the production cross-sections for curium isotopes in fast reactor spectra and to the analysis of irradiated fuel for alpha emitting higher actinide nuclides are discussed.

  11. Nuclear fuel assemblies' deformations measurement by optoelectronic methods in cooling ponds

    NASA Astrophysics Data System (ADS)

    Senchenko, E. S.; Zavyalov, P. S.; Finogenov, L. V.; Khakimov, D. R.

    2013-12-01

    Increasing the reliability and life-time of nuclear fuel is actual problems for nuclear power engineering. It takes to provide the high geometric stability of nuclear fuel assemblies (FA) under exploitation, since various factors cause FA mechanical deformation (bending and twisting). To obtain the objective information and make recommendations for the FA design improvement one have to fulfill the post reactor FA analysis. Therefore it takes measurements of the FA geometric parameters in cooling ponds of nuclear power plants. As applied to this problem we have developed and investigated the different optoelectronic methods, namely, structured light method, television and shadow ones. In this paper effectiveness of these methods has been investigated using the special experimental test stand and fulfilled researches are described. The experimental results of FA measurements by different methods and recommendation for their usage is given.

  12. Measurement of Nuclear Transparency from A(e,e',π+) Reactions

    SciTech Connect

    Clasie, Benjamin

    2006-08-01

    We have measured the nuclear transparency of the A(e, e' π+) process in 2H,12C, 27Al, 63Cu and 197Au targets. These measurements were performed at the Jefferson Laboratory over a four momen- tum transfer squared range Q2 = 1.1 to 4.7 (GeV/c)2. The nuclear transparency was extracted as the super-ratio of ( σA/ σH) from data to a model of pion-electroproduction from nuclei without N final state interactions. The Q2 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.

  13. 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):

  14. Human platelet diffusional water permeability measured by nuclear magnetic resonance.

    PubMed

    Wong, K R; Verkman, A S

    1987-06-01

    To examine whether water transport in human platelets is mediated by an aqueous pore or channel, the ratio of osmotic to diffusional water permeability coefficients (Pf/Pd) was measured. Pd was measured from protein spin-lattice relaxation times in a dense platelet suspension (approximately 20% intracellular exchangeable water) using 20 mM solution Mn as a paramagnetic quencher. The decay of magnetization was biexponential with time constants of 1.3 and 6.9 ms (10 MHz, 37 degrees C), corresponding to a Pd of (2.9 +/- 0.2) X 10(-3) cm/s (SE; n = 8). Pd did not depend on concentrations of Mn (6-20 mM) or of platelets (2-4 X 10(10) platelets/ml), but increased to 4.5 X 10(-3) cm/s with addition of gramicidin (6 micrograms/10(10) platelets). 54Mn uptake studies showed less than 1% of equilibrium uptake of Mn into platelets in 30 min at 37 degrees C. The activation energies (Ea) for Pd were 4.5 kcal/mol (less than 28 degrees C) and 16.3 kcal/mol (greater than 28 degrees C). Pf was measured by a stopped-flow light scattering technique as reported previously [M. M. Meyer and A. S. Verkman, Human platelet osmotic water and nonelectrolyte transport, Am. J. Physiol. 251 (Cell Physiol. 20): C549-C557, 1986], in which the time course of platelet volume was measured in response to a 100 mM inwardly directed sucrose gradient. At 37 degrees C, Pf was (2.7 +/- 0.2) X 10(-3) cm/s and independent of [Mn]. The measured platelet Pf/Pd of 0.93 +/- 0.1 suggests that unlike water transport in erythrocytes, platelet water transport is not associated with an aqueous channel.

  15. 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.

  16. One centimeter spatial resolution temperature measurements in a nuclear reactor using Rayleigh scatter in optical fiber

    NASA Astrophysics Data System (ADS)

    Sang, A. K.; Gifford, D. K.; Dickerson, B. D.; Fielder, B. F.; Froggatt, M. E.

    2007-07-01

    We present the use of swept wavelength interferometry for distributed fiber-optic temperature measurements in a Nuclear Reactor. The sensors consisted of 2 m segments of commercially available, single mode optical fibers. The interrogation technique is based on measuring the spectral shift of the intrinsic Rayleigh backscatter signal along the optical fiber and converting the spectral shift to temperature.

  17. 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.

  18. Nuclear Threat Reduction Measures for India and Pakistan

    DTIC Science & Technology

    2005-02-17

    drive systems, and on-line fuel charging and discharging equipment for CANDU reactors. considered to have made “substantial progress in the...Reduction Measures for India and Pakistan Updated February 17, 2005 Sharon Squassoni Specialist in National Defense Foreign Affairs, Defense, and Trade...hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and

  19. Nuclear Astrophysics and Neutron Cross Section Measurements Using the ORELA

    SciTech Connect

    Winters, R. R.

    2000-08-25

    This is the final report for a research program which has been continuously supported by the AEC, ERDA, or USDOE since 1973. The neutron total and capture cross sections for n + {sup 88}Sr have been measured over the neutron energy range 100 eV to 1 MeV. The report briefly summaries our results and the importance of this work for nucleosynthesis and the optical model.

  20. Neutron scattering and models: Iron. Nuclear data and measurements series

    SciTech Connect

    Smith, A.B.

    1995-08-01

    Differential elastic and inelastic neutron-scattering cross sections of elemental iron are measured from 4.5 to 10 MeV in increments of {approx} 0.5 MeV. At each incident energy the measurements are made at forty or more scattering angles distributed between {approx} 17{degrees} and 160{degrees}, with emphasis on elastic scattering and inelastic scattering due to the excitation of the yrast 2{sup +} state. The measured data is combined with earlier lower-energy results from this laboratory, with recent high-precision {approx} 9.5 {yields} 15 MeV results from the Physilalisch Technische Bundesanstalt and with selected values from the literature to provide a detailed neutron-scattering data base extending from {approx} 1.5 to 26 MeV. This data is interpreted in the context of phenomenological spherical-optical and coupled-channels (vibrational and rotational) models, and physical implications discussed. Deformation, coupling, asymmetry and dispersive effects are explored. It is shown that, particularly in a collective context, a good description of the interaction of neutrons with iron is achieved over the energy range {approx} 0 {yields} 26 MeV, avoiding the dichotomy between high and low-energy interpretations found in previous work.

  1. 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.

  2. The effective excitonic g factors of Mn-doped InAs nanowires

    NASA Astrophysics Data System (ADS)

    Xiong, Wen

    2017-04-01

    Based on the derived eight-band k · p Hamiltonian, the electronic structures of Mn-doped InAs nanowires in the magnetic field are calculated. We find the lowest optical transition will be split to four individual transitions when the magnetic field is applied along z axis, and two of them are σ polarized light. Furthermore, the Zeeman splitting energy at the Γ point of two σ polarized light will increase nonlinearly as the increase of the magnetic field. Additionally, an effective excitonic g factor at the Γ point is defined, and the effective excitonic g factors will decrease greatly with the increase of the radius of nanowires and the decrease of the concentration of manganese ions, while the effective excitonic g factors decrease slightly when the magnetic field increases. Interestingly, the effective excitonic g factors can experience a substantial decrease when the temperature increases from 10 K to 100 K and is almost not affected when the temperature varies from 100 K to 300 K. Therefore, we can infer that large effective excitonic g factors can be obtained when small radius of nanowires, high concentration of manganese ions and low temperature are satisfied.

  3. Activities on Nuclear Data Measurements at Pohang Neutron Facility

    NASA Astrophysics Data System (ADS)

    Kim, Guinyun

    2009-03-01

    We report the activities of the Pohang Neutron Facility which consists of an electron linear accelerator, a water-cooled Ta target, and a 12-m time-of-flight path. It has been equipped with a four-position sample changer controlled remotely by a CAMAC data acquisition system, which allows simultaneous accumulation of the neutron time of flight spectra from 4 different detectors. It can be possible to measure the neutron total cross-sections in the neutron energy range from 0.1 eV to few hundreds eV by using the neutron time-of-flight method. A 6LiZnS(Ag) glass scintillator was used as a neutron detector. The neutron flight path from the water-cooled Ta target to the neutron detector was 12.1 m. The background level was determined by using notch-filters of Co, In, Ta, and Cd sheets. In order to reduce the gamma rays from bremsstrahlung and those from neutron capture, we employed a neutron-gamma separation system based on their different pulse shapes. The present measurements of several samples (Ta, Mo) are in general agreement with the evaluated data in ENDF/B-VI. We measured the thermal neutron capture cross-sections and the resonance integrals of the 186W(n,γ)187W reaction and the 98Mo(n,γ)99Mo reaction by the activation method using the 197Au(n,γ)198Au monitor reaction as a single comparator. We also report the isomeric yield ratios for the 44 m, gSc isomeric pairs produced from four different photonuclear reactions 45Sc(γ,n)44m,gSc, natTi(γ,xn1p)44m,gSc, natFe(γ,xn5p)52m,gMn, and 103Rh(γ,4n)99m,gRh by using the activation method.

  4. 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.

  5. 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.

  6. Gate-controlled electron g-factor in lateral quantum dot molecules

    NASA Astrophysics Data System (ADS)

    Ribeiro-Santos, D.; Qu, Fanyao; Morais, P. C.; Lopez-Richard, V.; Marques, G. E.

    2011-12-01

    We investigate theoretically the tunability of the effective electron g-factor in lateral double quantum dots, subjected simultaneously to spin-orbit interaction and vertical electrical and magnetic fields. We find that, by sweeping interdot barrier voltage or by changing interdot distance, the character of the electronic states can be modified from atomic-like to molecular-like and vice-versa. We report theoretical predictions for interdot voltage induced giant effective g-factor and study its dependence on the spin-orbit interaction strength. To avoid numerical artifacts in the single-electron energy spectrum, we adopt a set of modified Gaussian functions as basis, divide the full Hilbert space into orthogonal sub-spaces, and use an exact diagonalization method. In order to correct ill-definitions of g-factor found in the literature, we point out an unambiguous way to evaluate it.

  7. Many-electron QED corrections to the g factor of lithiumlike ions.

    PubMed

    Volotka, A V; Glazov, D A; Shabaev, V M; Tupitsyn, I I; Plunien, G

    2014-06-27

    A rigorous QED evaluation of the two-photon exchange corrections to the g factor of lithiumlike ions is presented. The screened self-energy corrections are calculated for the intermediate-Z region, and its accuracy for the high-Z region is essentially improved in comparison with that of previous calculations. As a result, the theoretical accuracy of the g factor of lithiumlike ions is significantly increased. The theoretical prediction obtained for the g factor of (28)Si(11+) g(th) = 2.000 889 892(8) is in an excellent agreement with the corresponding experimental value g(exp) = 2.000 889 889 9(21) [A. Wagner et al., Phys. Rev. Lett. 110, 033003 (2013).

  8. 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.

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

    PubMed

    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; Paetz gen Schieck, Hans

    2014-10-01

    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 H2(+) (or D2(+)) ions into the Lamb-shift polarimeter.

  10. Calibration of stack monitors for measurement of noble gases in nuclear facilities.

    PubMed

    Kovar, Petr; Dryak, Pavel; Suran, Jiri; Gudelis, Arunas

    2012-09-01

    In nuclear facilities stack monitors are used for the measurement of the volumetric activity of noble gases. Spectrometric measurement is needed because the content of stack effluents is always a mixture of radionuclides. In some nuclear power plants new types of monitors were installed based on HPGe detectors. For efficiency calibration a standard with the radionuclide Xe-127 was developed and calibration curve constructed in the energy range 81 keV-1293 keV. Experiental efficiencies were checked using an MC model.

  11. 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.

  12. 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.

  13. Measurements of Argon-39 at the U20az underground nuclear explosion site.

    PubMed

    McIntyre, J I; Aalseth, C E; Alexander, T R; Back, H O; Bellgraph, B J; Bowyer, T W; Chipman, V; Cooper, M W; Day, A R; Drellack, S; Foxe, M P; Fritz, B G; Hayes, J C; Humble, P; Keillor, M E; Kirkham, R R; Krogstad, E J; Lowrey, J D; Mace, E K; Mayer, M F; Milbrath, B D; Misner, A; Morley, S M; Panisko, M E; Olsen, K B; Ripplinger, M D; Seifert, A; Suarez, R

    2017-07-26

    Pacific Northwest National Laboratory reports on the detection of (39)Ar at the location of an underground nuclear explosion on the Nevada Nuclear Security Site. The presence of (39)Ar was not anticipated at the outset of the experimental campaign but results from this work demonstrated that it is present, along with (37)Ar and (85)Kr in the subsurface at the site of an underground nuclear explosion. Our analysis showed that by using state-of-the-art technology optimized for radioargon measurements, it was difficult to distinguish (39)Ar from the fission product (85)Kr. Proportional counters are currently used for high-sensitivity measurement of (37)Ar and (39)Ar. Physical and chemical separation processes are used to separate argon from air or soil gas, yielding pure argon with contaminant gases reduced to the parts-per-million level or below. However, even with purification at these levels, the beta decay signature of (85)Kr can be mistaken for that of (39)Ar, and the presence of either isotope increases the measurement background level for the measurement of (37)Ar. Measured values for the (39)Ar measured at the site ranged from 36,000 milli- Becquerel/standard-cubic-meter-of-air (mBq/SCM) for shallow bore holes to 997,000 mBq/SCM from the rubble chimney from the underground nuclear explosion. Copyright © 2017. Published by Elsevier Ltd.

  14. Parametric CI+MBPT calculations of Th I energies and g-factors for even states

    NASA Astrophysics Data System (ADS)

    Savukov, I. M.

    2017-08-01

    In this paper, we study energies and g-factors for a large number of levels of Th I. We found that the accuracy of configuration-interaction many-body perturbation theory can be substantially improved by using multiple adjustment parameters, which are introduced to regulate the second-order MBPT corrections for single-valence energies and Coulomb interaction. The results for energies and g-factors are in excellent agreement with experiment, with accuracy sufficient to positively assign theoretical states of given angular momentum and parity to experimental levels. This theory will be further developed in the future to treat other, even more complicated, actinides such as U I.

  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. 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.

  17. Direct Measurement of the g-factor in crystalline bismuth at high B/T

    NASA Astrophysics Data System (ADS)

    Bompadre, Silvia; Biagini, Cristiano; Maslov, Dmitrii; Hebard, Arthur

    2000-03-01

    Magneto transport data have been obtained for high purity bismuth crystals with various orientations in fields B as high as 20T and temperatures as low as 25mK. For fields on the order of 15T in the trigonal direction we find, in agreement with theoretical expectations, that all holes are in the lowest Landau level. More than twenty-five Shubnikov de Haas oscillations due to holes are observed. Electron oscillations are strongly attenuated. Close inspection of the data reveals a non-linear correction to the reciprocal field spacings together with the appearance of doublets at each field oscillation with spacings that scale as B^2. The absence of a doublet in the n=1 Landau level allows us to conclude that the Zeeman splitting is sufficiently strong to fully polarize the holes in the n=0,1,2 Landau levels. This information together with the quadratic dependence of the doublets allows us to infer g = 34 for holes.

  18. 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

  19. Neutron Cross Section Measurements at ORELA for Improved Nuclear Data and Their Application

    SciTech Connect

    Guber, Klaus H; Leal, Luiz C; Sayer, Royce O; Koehler, Paul Edward; Valentine, Timothy E; Derrien, Herve; Harvey, John A

    2005-02-01

    Many older neutron cross-section evaluations from libraries such as ENDF/B-VI or JENDL-3.2 exhibit deficiencies or do not cover energy ranges that are important for criticality safety applications. These deficiencies may occur in the resolved and unresolved-resonance regions. Consequently, these evaluated data may not be adequate for nuclear criticality calculations where effects such as self-shielding, multiple scattering, or Doppler broadening are important. To support the Nuclear Criticality Predictability Program, neutron cross-section measurements have been initiated at the Oak Ridge Electron Linear Accelerator (ORELA). ORELA is the only high-power white neutron source with excellent time resolution still operating in the United States. It is ideally suited to measure fission, neutron total, and capture cross sections in the energy range from 1 eV to {approx}600 keV, which is important for many nuclear criticality safety applications.

  20. New Neutron Cross Section Measurements at ORELA for Improved Nuclear Data

    SciTech Connect

    Guber, Klaus H; Leal, Luiz C; Sayer, Royce O; Koehler, Paul Edward; Valentine, Timothy E; Derrien, Herve; Harvey, John A

    2004-07-01

    Many older neutron cross-section evaluations from libraries such as ENDF/B-VI or JENDL-3.2 exhibit deficiencies or do not cover energy ranges that are important for criticality safety applications. These deficiencies may occur in the resolved and unresolved-resonance regions. Consequently, these evaluated data may not be adequate for nuclear criticality calculations where effects such as self-shielding, multiple scattering, or Doppler broadening are important. To support the Nuclear Criticality Predictability Program, neutron cross-section measurements have been initiated at the Oak Ridge Electron Linear Accelerator (ORELA). ORELA is the only high-power white neutron source with excellent time resolution still operating in the United States. It is ideally suited to measure fission, neutron total, and capture cross sections in the energy range from 1 eV to {approx}600 keV, which is important for many nuclear criticality safety applications.

  1. New Neutron Cross-Section Measurements at ORELA for Improved Nuclear Criticality Calculations

    SciTech Connect

    Guber, Klaus H; Leal, Luiz C; Sayer, Royce O; Koehler, Paul Edward; Valentine, Timothy E; Derrien, Herve; Harvey, John A

    2005-05-01

    Many older neutron cross-section evaluations from libraries such as ENDF/B-VI or JENDL-3.2 exhibit deficiencies or do not cover energy ranges that are important for criticality safety applications. These deficiencies may occur in the resolved and unresolved-resonance regions. Consequently, these evaluated data may not be adequate for nuclear criticality calculations where effects such as self-shielding, multiple scattering, or Doppler broadening are important. To support the Nuclear Criticality Predictability Program, neutron cross-section measurements have been initiated at the Oak Ridge Electron Linear Accelerator (ORELA). ORELA is the only high-power white neutron source with excellent time resolution still operating in the United States. It is ideally suited to measure fission, neutron total, and capture cross sections in the energy range from 1 eV to {approx}600 keV, which is important for many nuclear criticality safety applications.

  2. New Neutron Cross-Section Measurements at ORELA for Improved Nuclear Data Calculations

    SciTech Connect

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

    2005-05-24

    Many older neutron cross-section evaluations from libraries such as ENDF/B-VI or JENDL-3.2 exhibit deficiencies or do not cover energy ranges that are important for criticality safety applications. These deficiencies may occur in the resolved and unresolved-resonance regions. Consequently, these evaluated data may not be adequate for nuclear criticality calculations where effects such as self-shielding, multiple scattering, or Doppler broadening are important. To support the Nuclear Criticality Predictability Program, neutron cross-section measurements have been initiated at the Oak Ridge Electron Linear Accelerator (ORELA). ORELA is the only high-power white neutron source with excellent time resolution still operating in the United States. It is ideally suited to measure fission, neutron total, and capture cross sections in the energy range from 1 eV to {approx}600 keV, which is important for many nuclear criticality safety applications.

  3. 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.

  4. Tuneable paramagnetic susceptibility and exciton g-factor in Mn-doped PbS colloidal nanocrystals

    NASA Astrophysics Data System (ADS)

    Turyanska, L.; Hill, R. J. A.; Makarovsky, O.; Moro, F.; Knott, A. N.; Larkin, O. J.; Patanè, A.; Meaney, A.; Christianen, P. C. M.; Fay, M. W.; Curry, R. J.

    2014-07-01

    We report on PbS colloidal nanocrystals that combine within one structure solubility in physiological solvents with near-infrared photoluminescence, and magnetic and optical properties tuneable by the controlled incorporation of magnetic impurities (Mn). We use high magnetic fields (B up to 30 T) to measure the magnetization of the nanocrystals in liquid and the strength of the sp-d exchange interaction between the exciton and the Mn-ions. With increasing Mn-content from 0.1% to 7%, the mass magnetic susceptibility increases at a rate of ~10-7 m3 kg-1 per Mn percentage; correspondingly, the exciton g-factor decreases from 0.47 to 0.10. The controlled modification of the paramagnetism, fluorescence and exciton g-factor of the nanocrystals is relevant to the implementation of these paramagnetic semiconductor nanocrystals in quantum technologies ranging from quantum information to magnetic resonance imaging.We report on PbS colloidal nanocrystals that combine within one structure solubility in physiological solvents with near-infrared photoluminescence, and magnetic and optical properties tuneable by the controlled incorporation of magnetic impurities (Mn). We use high magnetic fields (B up to 30 T) to measure the magnetization of the nanocrystals in liquid and the strength of the sp-d exchange interaction between the exciton and the Mn-ions. With increasing Mn-content from 0.1% to 7%, the mass magnetic susceptibility increases at a rate of ~10-7 m3 kg-1 per Mn percentage; correspondingly, the exciton g-factor decreases from 0.47 to 0.10. The controlled modification of the paramagnetism, fluorescence and exciton g-factor of the nanocrystals is relevant to the implementation of these paramagnetic semiconductor nanocrystals in quantum technologies ranging from quantum information to magnetic resonance imaging. Electronic supplementary information (ESI) available: Details of the experiments techniques and results are available for the following studies: Raman and PL

  5. [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.

  6. Method of and apparatus for measuring the power distribution in nuclear reactor cores

    SciTech Connect

    Leyse, R.H.

    1983-07-12

    The invention disclosed is the method of exact calibration of gamma ray detectors called gamma thermometers prior to acceptance for installation into a nuclear reactor core. This exact calibration increases the accuracy of determining the power distribution in the nuclear reactor core. The calibration by electric resistance heating of the gamma thermometer consists of applying an electric current along the controlled heat path of the gamma thermometer and then measuring the temperature difference along this controlled heat path as a function of the amount of power generated by the electric resistance heating. Then, after the gamma thermometer is installed into the nuclear reactor core and the reactor core is operating at power producing conditions, the gamma ray heating of the detector produces a temperature difference along the controlled heat path. With the knowledge of this temperature difference, the calibration characteristic determined by the prior electric resistance heating is employed to accurately determine the local rate of gamma ray heating. The accurate measurement of the gamma heating rate at each location of a set of locations throughout the nuclear reactor core is the basis for accurately determining the power distribution within the nuclear reactor core.

  7. 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.

  8. Theory of g-factor enhancement in narrow-gap quantum well heterostructures

    NASA Astrophysics Data System (ADS)

    Krishtopenko, S. S.; Gavrilenko, V. I.; Goiran, M.

    2011-09-01

    We report on the study of the exchange enhancement of the g-factor in the two-dimensional (2D) electron gas in n-type narrow-gap semiconductor heterostructures. Our approach is based on the eight-band kṡp Hamiltonian and takes into account the band nonparabolicity, the lattice deformation, the spin-orbit coupling and the Landau level broadening in the δ-correlated random potential model. Using the ‘screened’ Hartree-Fock approximation we demonstrate that the exchange g-factor enhancement not only shows maxima at odd values of Landau level filling factors but, due to the conduction band nonparabolicity, persists at even filling factor values as well. The magnitude of the exchange enhancement, the amplitude and the shape of the g-factor oscillations are determined by both the screening of the electron-electron interaction and the Landau level width. The ‘enhanced’ g-factor values calculated for the 2D electron gas in InAs/AlSb quantum well heterostructures are compared with our earlier experimental data and with those obtained by Mendez et al (1993 Phys. Rev. B 47 13937) in magnetic fields up to 30 T.

  9. 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.

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

    PubMed Central

    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.

    2016-01-01

    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 95Zr and 97Zr. By measuring both the perturbation of the 95Mo/96Mo and 97Mo/96Mo isotopic ratios and the total amount of molybdenum in the Trinity nuclear debris samples, it is possible to calculate the original concentrations of the 95Zr and 97Zr 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

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

    DOE PAGES

    Hanson, Susan Kloek; Pollington, Anthony Douglas; Waidmann, Christopher Russell; ...

    2016-07-05

    This study 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 95Zr and 97Zr. By measuring both the perturbation of the 95Mo/96Mo and 97Mo/96Mo isotopic ratios and the total amount of molybdenum in the Trinity nuclear debris samples, it is possible to calculate the original concentrations of the 95Zr and 97Zrmore » 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.« less

  12. 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…

  13. 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)

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

    USDA-ARS?s Scientific Manuscript database

    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...

  15. 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…

  16. 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.

  17. 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)

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

    USDA-ARS?s Scientific Manuscript database

    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...

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

    DOE PAGES

    Fenker, B.; Behr, J. A.; Melconian, D.; ...

    2016-07-13

    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 themore » $${\\beta }^{+}$$-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 $$\\bar{P}=0.9913\\pm 0.0009$$, 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.« less

  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. Transmission Nuclear Resonance Fluorescence Measurements of 238U in Thick Targets

    SciTech Connect

    Quiter, Brian J.; Ludewigt, Bernhard A.; Mozin, Vladimir V.; Wilson, Cody; Korbly, Steve

    2010-08-31

    Transmission nuclear resonance fluorescence measurements were made on targets consisting of Pb and depleted U with total areal densities near 86 g/cm2. The 238U content n the targets varied from 0 to 8.5percent (atom fraction). The experiment demonstrates the capability of using transmission measurements as a non-destructive technique to identify and quantify the presence of an isotope in samples with thicknesses comparable to he average thickness of a nuclear fuel assembly. The experimental data also appear to demonstrate the process of notch refilling with a predictable intensity. Comparison of measured spectra to previous backscatter 238U measurements indicates general agreement in observed excited states. Two new 238U excited states and possibly a third state have also been observed.

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

    SciTech Connect

    Clark, Jason

    2016-06-21

    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.

  4. Measurements of nuclear-level lifetimes by the Doppler techniques with large multidetector arrays

    SciTech Connect

    Pasternak, A. A.

    2008-07-15

    This is a brief review of the investigations carried out by scientists from the Ioffe Physical-Technical Institute (St. Petersburg) within the framework of international projects for the study of the structure of high-spin nuclear states using heavy-ion beams and arrays of tens and hundreds of detectors for recording gamma rays and charged particles. The development and results of measurements of nuclear-level lifetime by Doppler techniques in the range 10{sup -14}-10{sup -9} s are discussed.

  5. 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.

  6. An Information Approach To Model Selection For Feedwater Inferential Measurements In A Nuclear Power Plant

    SciTech Connect

    Urmanov, Aleksey M.; Gribok, Andrei V.; Hines, J. Wesley; Uhrig, Robert E.

    2002-07-01

    Inferential sensing is a method that can be used to evaluate the parameters of a physical system based on a set of measurements related to those parameters. Inferential sensing uses mathematical models to infer the parameter value from correlated sensor values. However, inferential sensing is an ill-posed problem because of non-uniqueness and instability of the solution. This paper shows that complexity-penalized model selection can be used to produce a unique and stable solution. An important example of monitoring the nuclear power plant feedwater flow rate is given using data from Carolina Power and Light's Crystal River Nuclear Power Plant. (authors)

  7. Optical control over electron g factor and spin decoherence in (In ,Ga ) As /Ga As quantum dots

    NASA Astrophysics Data System (ADS)

    Rietjens, J. H. H.; Quax, G. W. W.; Bosco, C. A. C.; Nötzel, R.; Silov, A. Yu.; Koopmans, B.

    2008-04-01

    We have studied the dependence of the electron in-plane g factor and spin decoherence time on the built-in electric field (Ei) at the position of a single layer of self-assembled (In ,Ga ) As /Ga As quantum dots (QDs). Control of Ei is achieved by inducing screening charges in a p -i -n GaAs matrix with a continuous wave (cw) laser. Using a time-resolved pump-probe technique to measure the spin dynamics via the magneto-optical Kerr effect, we observe a large hole spin decoherence time of 440 ps . Measurements as function of the cw laser power and, thus, of Ei show that the electron spin decay time in the QDs depends strongly on Ei and decreases from 310 to110 ps with increasing Ei. We attribute this effect to increasing tunneling rates of electrons out of the QDs at high Ei. We observe a slight increase of the electron g factor from 0.40 ±0.03 to 0.46 ±0.04 with increasing Ei, which might be a result of a changing wavefunction as a result of a different confinement potential due to Ei.

  8. Measurement of prompt neutron generation time at the VIR-2M pulsed nuclear reactor

    NASA Astrophysics Data System (ADS)

    Glukhov, L. Yu.; Kotkov, S. P.; Kuznetsov, M. S.; Chursin, S. S.

    2016-12-01

    The prompt neutron generation time is measured in the core of the VIR-2M research nuclear reactor. The measurements are performed using the Babala method while the reactor is in the subcritical state. The VIR-2M reactor and the relevant experimental equipment are briefly described, and the experimental procedure and data processing technique are presented. It is shown that the prompt neutron generation time with empty experimental channels is 35 ± 1 μs.

  9. Measurement of prompt neutron generation time at the VIR-2M pulsed nuclear reactor

    SciTech Connect

    Glukhov, L. Yu.; Kotkov, S. P.; Kuznetsov, M. S.; Chursin, S. S.

    2016-12-15

    The prompt neutron generation time is measured in the core of the VIR-2M research nuclear reactor. The measurements are performed using the Babala method while the reactor is in the subcritical state. The VIR-2M reactor and the relevant experimental equipment are briefly described, and the experimental procedure and data processing technique are presented. It is shown that the prompt neutron generation time with empty experimental channels is 35 ± 1 μs.

  10. 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.

  11. 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.

  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. Unveiling saturation effects from nuclear structure function measurements at the EIC

    NASA Astrophysics Data System (ADS)

    Marquet, Cyrille; Moldes, Manoel R.; Zurita, Pía

    2017-09-01

    We analyze the possibility of extracting a clear signal of non-linear parton saturation effects from future measurements of nuclear structure functions at the Electron-Ion Collider (EIC), in the small-x region. Our approach consists in generating pseudodata for electron-gold collisions, using the running-coupling Balitsky-Kovchegov evolution equation, and in assessing the compatibility of these saturated pseudodata with existing sets of nuclear parton distribution functions (nPDFs), extrapolated if necessary. The level of disagreement between the two is quantified by applying a Bayesian reweighting technique. This allows to infer the parton distributions needed in order to describe the pseudodata, which we find quite different from the actual distributions, especially for sea quarks and gluons. This tension suggests that, should saturation effects impact the future nuclear structure function data as predicted, a successful refitting of the nPDFs may not be achievable, which would unambiguously signal the presence of non-linear effects.

  15. Damage dosimetry and embrittlement monitoring of nuclear pressure vessels in real time by magnetic properties measurement

    SciTech Connect

    Stubbins, J.F.; Ougouag, A.M.; Williams, J.G.

    1992-07-01

    The objective of this project is to develop a technique for real-time monitoring of neutron dose and of the onset and progression of embrittlement in operating nuclear pressure vessels. The technique relies on the measurement of magnetic properties of steel and other magnetic materials which are extremely sensitive to radiation-induced properties changes. The approach being developed here is innovative and unique. It promises to be readily applicable to all existing and planned reactor structures. The significance of this program is that it addresses a major concern in the operation of existing nuclear pressure vessels. The development of microscopic defect clusters during irradiation in the nuclear pressure vessel beltline region leads to an increase in material yield strength and a concomitant decrease in ductility, or ability to absorb energy in fracture (i.e. fracture toughness). This decrease in fracture toughness is alarming since it may impair the ability of the pressure vessel to resist fracture during unusual loading situations.

  16. Measuring the Low Energy Nuclear Quenching Factor in Liquid Argon for a Coherent Neutrino Scatter Detector

    NASA Astrophysics Data System (ADS)

    Foxe, M.; Bernstein, A.; Hagmann, C.; Joshi, T.; Jovanovic, I.; Kazkaz, K.; Sangiorgio, S.

    2012-08-01

    Coherent neutrino-nucleus scattering (CNS) is an as-yet undetected, flavor-independent neutrino interaction predicted by the Standard Model [D. Freedman, Phys. Rev. D 9 (5) (1974) 1389-1392]. One of the primary reasons the CNS interaction has yet to be observed is the very low energy depositions (less than 1 keV for MeV-energy neutrinos) [A. Drukier, L. Stodolsky, Phys. Rev. D 30 (11) (1984) 2295-2309]. An additional challenge in detecting CNS is nuclear quenching, which is a phenomenon encountered in many detection materials in which nuclear recoils produce less observable energy per unit energy deposited than electronic recoils. The ratio observed signal for nuclear recoils to electronic recoils or nuclear ionization quench factor, is presently unknown in argon at typical CNS energies [C. Hagmann, A. Bernstein, IEEE Trans. on Nucl. Sci. 51 (5) (2004) 2151-2155]. Here we present plans for using the Gamma or Neutron Argon Recoils Resulting in Liquid Ionization (G/NARRLI) detector to measure the nuclear ionization quench factor at ˜8 keV.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Compilation of directly measured nuclear spins of ground states and long-lived isomers

    SciTech Connect

    MacDonald, Allison; Karamy, Babak; Setoodehnia, Kiana; Singh, Balraj

    2013-02-15

    A compilation of the nuclear spins of ground and isomeric states measured by direct methods is presented. The first compilation of direct measurements of nuclear spins and moments was published in 1976 (G. H. Fuller, J. Phys. Chem. Ref. Data 5, 835, (1976)) with literature covered up to 1974. To our knowledge, the present work is the first such compilation since then. It is anticipated that the area of direct spin measurement will continue to expand using the state-of-the-art radioactive ion-beam and laser techniques. Literature cutoff date for the present compilation is February 2013. It is intended that the present compilation will be kept updated in a timely manner.

  2. Time-correlated pulse-height measurements of low-multiplying nuclear materials

    NASA Astrophysics Data System (ADS)

    Miller, E. C.; Dolan, J. L.; Clarke, S. D.; Pozzi, S. A.; Tomanin, A.; Peerani, P.; Marleau, P.; Mattingly, J. K.

    2013-11-01

    Methods for the determination of the subcritical neutron multiplication of nuclear materials are of interest in the field of nuclear nonproliferation and safeguards. A series of measurements were performed at the Joint Research Center facility in Ispra, Italy to investigate the possibility of using a time-correlated pulse-height (TCPH) analysis to estimate the sub-critical multiplication of nuclear material. The objective of the measurements was to evaluate the effectiveness of this technique, and to benchmark the simulation capabilities of MCNPX-PoliMi/MPPost. In this campaign, two low-multiplication samples were measured: a 1-kg mixed oxide (MOX) powder sample and several low-mass plutonium-gallium (PuGa) disks. The measured results demonstrated that the sensitivity of the TCPH technique could not clearly distinguish samples with very-low levels of multiplication. However, the simulated TCPH distributions agree well with the measured data, within 12% for all cases, validating the simulation capabilities of MCNPX-PoliMi/MPPost. To investigate the potential of the TCPH method for identifying high-multiplication samples, the validated MCNPX-PoliMi/MPPost codes were used to simulate sources of higher multiplications. Lastly, a characterization metric, the cumulative region integral (CRI), was introduced to estimate the level of multiplication in a source. However, this response was shown to be insensitive over the range of multiplications of interest.

  3. 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

  4. 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.

  5. Measurement of Quark Energy Loss in Cold Nuclear Matter at Fermilab E906/SeaQuest

    SciTech Connect

    Lin, Po-Ju

    2017-01-01

    Parton energy loss is a process within QCD that draws considerable interest. The measurement of parton energy loss can provide valuable information for other hard-scattering processes in nuclei, and also serves as an important tool for exploring the properties of the quark-gluon plasma (QGP). Quantifying the energy loss in cold nuclear matter will help to set a baseline relative to energy loss in the QGP. With the Drell-Yan process, the energy loss of incoming quarks in cold nuclear matter can be ideally investigated since the final state interaction is expected to be minimal. E906/SeaQuest is a fixed-target experiment using the 120 GeV proton beam from the Fermilab Main Injector and has been collecting data from p+p, p+d, p+C, p+Fe, and p+W collisions. Within the E906 kinematic coverage of Drell-Yan production via the dimuon channel, the quark energy loss can be measured in a regime where other nuclear effects are expected to be small. In this thesis, the study of quark ener gy loss from different cold nuclear targets is presented.

  6. 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.

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

    DOE PAGES

    Skripnikov, L. V.; Petrov, A. N.; Titov, A. V.; ...

    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

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

    SciTech Connect

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

    2016-01-04

    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.

  9. Quantized Conductance and Large g-Factor Anisotropy in InSb Quantum Point Contacts.

    PubMed

    Qu, Fanming; van Veen, Jasper; de Vries, Folkert K; Beukman, Arjan J A; Wimmer, Michael; Yi, Wei; Kiselev, Andrey A; Nguyen, Binh-Minh; Sokolich, Marko; Manfra, Michael J; Nichele, Fabrizio; Marcus, Charles M; Kouwenhoven, Leo P

    2016-12-14

    Because of a strong spin-orbit interaction and a large Landé g-factor, InSb plays an important role in research on Majorana fermions. To further explore novel properties of Majorana fermions, hybrid devices based on quantum wells are conceived as an alternative approach to nanowires. In this work, we report a pronounced conductance quantization of quantum point contact devices in InSb/InAlSb quantum wells. Using a rotating magnetic field, we observe a large in-plane (|g1| = 26) and out-of-plane (|g1| = 52) g-factor anisotropy. Additionally, we investigate crossings of subbands with opposite spins and extract the electron effective mass from magnetic depopulation of one-dimensional subbands.

  10. 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 ) .

  11. 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.

  12. Virtual light-by-light scattering and the g factor of a bound electron

    SciTech Connect

    Lee, R.N.; Milstein, A.I.; Terekhov, I.S.; Karshenboim, S.G.

    2005-05-15

    The contribution of the light-by-light diagram to the g factor of an electron and muon bound in a Coulomb field is obtained. For an electron in a ground state, our results are in good agreement with the results of other authors obtained numerically for large Z. For relatively small Z our results have essentially higher accuracy as compared to the previous ones. For muonic atoms, the contribution is obtained with a high accuracy in the whole region of Z.

  13. Nuclear data for nuclear transmutation

    SciTech Connect

    Harada, Hideo

    2009-05-04

    Current status on nuclear data for the study of nuclear transmutation of radioactive wastes is reviewed, mainly focusing on neutron capture reactions. It is stressed that the highest-precision frontier research in nuclear data measurements should be a key to satisfy the target accuracies on the nuclear data requested for realizing the nuclear transmutation.

  14. Nuclear data for nuclear transmutation

    NASA Astrophysics Data System (ADS)

    Harada, Hideo

    2009-05-01

    Current status on nuclear data for the study of nuclear transmutation of radioactive wastes is reviewed, mainly focusing on neutron capture reactions. It is stressed that the highest-precision frontier research in nuclear data measurements should be a key to satisfy the target accuracies on the nuclear data requested for realizing the nuclear transmutation.

  15. Prospects for using coherent elastic neutrino-nucleus scattering to measure the nuclear neutron form factor

    NASA Astrophysics Data System (ADS)

    Patton, Kelly; McLaughlin, Gail; Scholberg, Kate; Engel, Jon; Schunck, Nicolas

    2017-01-01

    Coherent elastic neutrino-nucleus scattering is a potential probe of nuclear neutron form factors. We show that the neutron root-mean-square (RMS) radius can be measured with tonne-scale detectors of argon, germanium, or xenon. In addition, the fourth moment of the neutron distribution can be studied experimentally using this method. The impacts of both detector size and detector shape uncertainty on such a measurement were considered. The important limiting factor was found to be the detector shape uncertainty. In order to measure the neutron RMS radius to 5%, comparable to current experimental uncertainties, the detector shape uncertainty needs to be known to 1% or better.

  16. TIME-OF-FLIGHT MASS MEASUREMENTS AND THEIR IMPORTANCE FOR NUCLEAR ASTROPHYSICS

    SciTech Connect

    Matos, M.; Shapira, Dan

    2009-01-01

    Atomic masses play an important role in nuclear astrophysics. The lack of experimental values for nuclides of interest has triggered a rapid development of new mass measurement devices around the world, including Time-of-Flight (TOF) mass measurements offering an access to the most exotic nuclides. Recently, the TOF-B rho technique that includes a position measurement for magnetic rigidity correction has been implemented at the NSCL. An experiment with a similar TOF-B rho technique is approved and planned at the next generation radioactive beam facility (RIBF) at RIKEN.

  17. Thoron activity level and radon measurement by a nuclear track detector.

    PubMed

    Planinić, J; Faj, Z; Vuković, B

    1993-03-01

    Radon activity concentrations in the air were measured with LR-115 nuclear track detectors at three locations in Osijek. The respective equilibrium factors and the effective dose equivalents were determined. Indoor concentrations were from 9.8 to 58.2 Bq m-3 and relative errors of the track etching method were near 19 per cent. The indoor alpha potential energy of the radon and thoron progenies was measured with an ISD detector. Independent measurements, performed with a Radhome semiconductor detector, showed that the indoor thoron concentration was nearly 20 per cent of the radon one.

  18. Time-of-Flight Mass Measurements and Their Importance for Nuclear Astrophysics

    NASA Astrophysics Data System (ADS)

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

    2009-03-01

    Atomic masses play an important role in nuclear astrophysics. The lack of experimental values for nuclides of interest has triggered a rapid development of new mass measurement devices around the world, including Time-of-Flight (TOF) mass measurements offering an access to the most exotic nuclides. Recently, the TOF-Brho technique that includes a position measurement for magnetic rigidity correction has been implemented at the NSCL. An experiment with a similar TOF-Brho technique is approved and planned at the next generation radioactive beam facility (RIBF) at RIKEN.

  19. Mental workload measurement for emergency operating procedures in digital nuclear power plants.

    PubMed

    Gao, Qin; Wang, Yang; Song, Fei; Li, Zhizhong; Dong, Xiaolu

    2013-01-01

    Mental workload is a major consideration for the design of emergency operation procedures (EOPs) in nuclear power plants. Continuous and objective measures are desired. This paper compares seven mental workload measurement methods (pupil size, blink rate, blink duration, heart rate variability, parasympathetic/sympathetic ratio, total power and (Goals, Operations, Methods, and Section Rules)-(Keystroke Level Model) GOMS-KLM-based workload index) with regard to sensitivity, validity and intrusiveness. Eighteen participants performed two computerised EOPs of different complexity levels, and mental workload measures were collected during the experiment. The results show that the blink rate is sensitive to both the difference in the overall task complexity and changes in peak complexity within EOPs, that the error rate is sensitive to the level of arousal and correlate to the step error rate and that blink duration increases over the task period in both low and high complexity EOPs. Cardiac measures were able to distinguish tasks with different overall complexity. The intrusiveness of the physiological instruments is acceptable. Finally, the six physiological measures were integrated using group method of data handling to predict perceived overall mental workload. The study compared seven measures for evaluating the mental workload with emergency operation procedure in nuclear power plants. An experiment with simulated procedures was carried out, and the results show that eye response measures are useful for assessing temporal changes of workload whereas cardiac measures are useful for evaluating the overall workload.

  20. 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.

  1. A measurement of the ionization efficiency of nuclear recoils in silicon

    NASA Astrophysics Data System (ADS)

    Izraelevitch, F.; Amidei, D.; Aprahamian, A.; Arcos-Olalla, R.; Cancelo, G.; Casarella, C.; Chavarria, A. E.; Collon, P.; Estrada, J.; Fernández Moroni, G.; Guardincerri, Y.; Gutiérrez, G.; Gyurjinyan, A.; Kavner, A.; Kilminster, B.; Liao, J.; Liu, Q.; López, M.; Molina, J.; Privitera, P.; Reyes, M. A.; Scarpine, V.; Siegl, K.; Smith, M.; Strauss, S.; Tan, W.; Tiffenberg, J.; Villanueva, L.

    2017-06-01

    We have measured the ionization efficiency of silicon nuclear recoils with kinetic energy between 1.8 and 20 keV . We bombarded a silicon-drift diode with a neutron beam to perform an elastic-scattering experiment. A broad-energy neutron spectrum was used and the nuclear recoil energy was reconstructed using a measurement of the time of flight and scattering angle of the scattered neutron. The overall trend of the results of this work is well described by the theory of Lindhard et al. above 4 keV of recoil energy. Below this energy, the presented data shows a deviation from the model. The data indicates a faster drop than the theory prediction at low energies.

  2. Nuclear Reaction Data from Surrogate Measurements: A Consideration of (n,f) Cross Sections

    SciTech Connect

    Escher, J E; Bernstein, L A; Burke, J T; Dietrich, F S; Lyles, B F

    2007-07-30

    A brief summary of the Surrogate reaction method, an indirect approach for determining compound-nuclear reaction cross sections, is presented. The possibilities for obtaining accurate (n,f) cross sections from Surrogate measurements that are analyzed in the Weisskopf-Ewing and Ratio approximations are considered. Theoretical studies and benchmark experiments that provide new insights into the validity and limitations of the Surrogate approach, are discussed.

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. Carbon fragmentation measurements and validation of the Geant4 nuclear reaction models for hadrontherapy.

    PubMed

    De Napoli, M; Agodi, C; Battistoni, G; Blancato, A A; Cirrone, G A P; Cuttone, G; Giacoppo, F; Morone, M C; Nicolosi, D; Pandola, L; Patera, V; Raciti, G; Rapisarda, E; Romano, F; Sardina, D; Sarti, A; Sciubba, A; Scuderi, V; Sfienti, C; Tropea, S

    2012-11-21

    Nuclear fragmentation measurements are necessary when using heavy-ion beams in hadrontherapy to predict the effects of the ion nuclear interactions within the human body. Moreover, they are also fundamental to validate and improve the Monte Carlo codes for their use in planning tumor treatments. Nowadays, a very limited set of carbon fragmentation cross sections are being measured, and in particular, to our knowledge, no double-differential fragmentation cross sections at intermediate energies are available in the literature. In this work, we have measured the double-differential cross sections and the angular distributions of the secondary fragments produced in the (12)C fragmentation at 62 A MeV on a thin carbon target. The experimental data have been used to benchmark the prediction capability of the Geant4 Monte Carlo code at intermediate energies, where it was never tested before. In particular, we have compared the experimental data with the predictions of two Geant4 nuclear reaction models: the Binary Light Ions Cascade and the Quantum Molecular Dynamic. From the comparison, it has been observed that the Binary Light Ions Cascade approximates the angular distributions of the fragment production cross sections better than the Quantum Molecular Dynamic model. However, the discrepancies observed between the experimental data and the Monte Carlo simulations lead to the conclusion that the prediction capability of both models needs to be improved at intermediate energies.

  8. Carbon fragmentation measurements and validation of the Geant4 nuclear reaction models for hadrontherapy

    NASA Astrophysics Data System (ADS)

    De Napoli, M.; Agodi, C.; Battistoni, G.; Blancato, A. A.; Cirrone, G. A. P.; Cuttone, G.; Giacoppo, F.; Morone, M. C.; Nicolosi, D.; Pandola, L.; Patera, V.; Raciti, G.; Rapisarda, E.; Romano, F.; Sardina, D.; Sarti, A.; Sciubba, A.; Scuderi, V.; Sfienti, C.; Tropea, S.

    2012-11-01

    Nuclear fragmentation measurements are necessary when using heavy-ion beams in hadrontherapy to predict the effects of the ion nuclear interactions within the human body. Moreover, they are also fundamental to validate and improve the Monte Carlo codes for their use in planning tumor treatments. Nowadays, a very limited set of carbon fragmentation cross sections are being measured, and in particular, to our knowledge, no double-differential fragmentation cross sections at intermediate energies are available in the literature. In this work, we have measured the double-differential cross sections and the angular distributions of the secondary fragments produced in the 12C fragmentation at 62 A MeV on a thin carbon target. The experimental data have been used to benchmark the prediction capability of the Geant4 Monte Carlo code at intermediate energies, where it was never tested before. In particular, we have compared the experimental data with the predictions of two Geant4 nuclear reaction models: the Binary Light Ions Cascade and the Quantum Molecular Dynamic. From the comparison, it has been observed that the Binary Light Ions Cascade approximates the angular distributions of the fragment production cross sections better than the Quantum Molecular Dynamic model. However, the discrepancies observed between the experimental data and the Monte Carlo simulations lead to the conclusion that the prediction capability of both models needs to be improved at intermediate energies.

  9. Use of DWPF redox measurement technique on glasses from West Valley Nuclear Fuel Services Demonstration Project

    SciTech Connect

    Jantzen, C.M.

    1990-10-01

    Liquid high-level nuclear waste will be immobilized at the Savannah River Site (SRS) by vitrification in borosilicate glass in the Defense Waste Processing Facility (DWPF). A similar vitrification facility exists at the West Valley Nuclear Fuel Services. In both of these facilities, control of the oxidation/reduction (redox) equilibrium in the glass melter is critical for processing of the nuclear waste. Redox can be determined by measuring the ratio of ferrous to ferric ions in the glass melt. A colorimetric procedure has been developed for the DWPF which has been shown to give rapid and reliable analytical results. This colorimetric technique has been shown to measure the Fe{sup 2+} component of glasses more accurately than other existing redox measurement methods. The DWPF redox technique was applied to a series of six glasses taken from the West Valley melter during a transient melter excursion. This excursion caused the glasses to become progressively more reducing with time. Application of the DWPF redox technique to these glasses correctly indicated the redox trends with a higher precision and with more accuracy than the West Valley wet chemical method and/or Alfred University's Mossbauer method. 1 fig., 18 refs.

  10. 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.

  11. Measurement of scintillation and ionization yield and scintillation pulse shape from nuclear recoils in liquid argon

    NASA Astrophysics Data System (ADS)

    Cao, H.; Alexander, T.; Aprahamian, A.; Avetisyan, R.; Back, H. O.; Cocco, A. G.; Dejongh, F.; Fiorillo, G.; Galbiati, C.; Grandi, L.; Guardincerri, Y.; Kendziora, C.; Lippincott, W. H.; Love, C.; Lyons, S.; Manenti, L.; Martoff, C. J.; Meng, Y.; Montanari, D.; Mosteiro, P.; Olvitt, D.; Pordes, S.; Qian, H.; Rossi, B.; Saldanha, R.; Sangiorgio, S.; Siegl, K.; Strauss, S. Y.; Tan, W.; Tatarowicz, J.; Walker, S.; Wang, H.; Watson, A. W.; Westerdale, S.; Yoo, J.; Scene Collaboration

    2015-05-01

    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 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 . We also 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 Krm83 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.

  12. DAPI-fluorescent fading: a problem in microscopy or a way to measure nuclear DNA content?

    NASA Astrophysics Data System (ADS)

    Gallardo-Escárate, Cristian; Álvarez-Borrego, Josué; Kober, V.; del Río-Portilla, Miguel Á.

    2006-01-01

    In observation by confocal or conventional fluorescence microscopy, the retardation of the lost in fluorescence, from highest signal of fluorescence to lowest intensity are important factors in order to obtain accurate images. This problem is very common in fluorochromes for nuclear DNA and especially for DAPI stain. The fluorescence of DAPI is rapidly lost when it is exposure to excitation by ultra violet (UV) light, and especially under optimal condition of observation. Although the fading process could be retardate by using of mounting medium with antifading solutions, the photochemical process underlying the fluorescence decay has not yet been fully explained. In addiction, neither relationship has been tested between the fluorescence fading and nuclear DNA content. However, the capacity of the DNA to absorb UV light is knows. In order to test this relationship we measured by means of image analysis the fluorescence intensity in several nuclei types during a fading period. The analysis was performed by an algorithm specifically built in MATLAB software. The relationship between nuclear DNA content and DAPI-fluorescence fading was found equal to 99%. This study demonstrates the feasibility for estimates genome size by quantification of fluorescence fading. In this context, the present method allows to measure nuclear DNA content in several medical applications (cancer, HIV, organ transplants, etc). Nowadays, for measuring DNA content, flow cytometry is widely used; however, with the flow cytometry method it is not possible to select a specific group of cells, such as from a specific region of a tumor. Moreover, the using of image analysis allows automatizing diagnostics procedures.

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

    DOE PAGES

    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

  14. Measurement of scintillation and ionization yield and scintillation pulse shape from nuclear recoils in liquid argon

    SciTech Connect

    Cao, H.; Alexander, T.; Aprahamian, A.; Avetisyan, R.; Back, H. O.; Cocco, A. G.; DeJongh, F.; Fiorillo, G.; Galbiati, C.; Grandi, L.; Guardincerri, Y.; Kendziora, C.; Lippincott, W. H.; Love, C.; Lyons, S.; Manenti, L.; Martoff, C. J.; Meng, Y.; Montanari, D.; Mosteiro, P.; Olvitt, D.; Pordes, S.; Qian, H.; Rossi, B.; Saldanha, R.; Sangiorgio, S.; Siegl, K.; Strauss, S. Y.; Tan, W.; Tatarowicz, J.; Walker, S.; Wang, H.; Watson, A. W.; Westerdale, S.; Yoo, J.

    2015-05-01

    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 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 . We also 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 83 m Kr internal conversion electrons is comparable to that from 207 Bi conversion electrons, we obtained the numbers of excitons ( N ex ) and ion pairs ( N i ) and their ratio ( N ex / N i ) 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.

  15. 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.

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

    SciTech Connect

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

    2016-07-07

    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.

  17. A novel approach for measuring the beta-neutrino angular correlation in nuclear beta decay

    NASA Astrophysics Data System (ADS)

    Beck, M.; Ames, F.; Beck, D.; Delauré, B.; Deutsch, J.; Bollen, G.; Forstner, O.; Phalet, T.; Quint, W.; Schmidt, P.; Schuurmans, P.; Severijns, N.; Vereecke, B.; Versyck, S.

    2000-12-01

    The experiment described here will search for deviations from the V-A structure of the standard electroweak model. It is based on measuring the recoil energy spectrum in nuclear beta decay which is determined by the electron-neutrino angular correlation. For pure Fermi decays this is exactly known in the standard model and any deviation will point to additional scalar interaction. The experiment consists of a Penning trap coupled to a retardation spectrometer to measure the energy of the recoiling daughter nuclei. The current status will be presented.

  18. 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.

  19. Theoretical study of the g factor and lifetime of the 6 s 6 p P30 state of mercury

    NASA Astrophysics Data System (ADS)

    Porsev, S. G.; Safronova, U. I.; Safronova, M. S.

    2017-07-01

    We calculate the g factor of the 6 s 6 p P30 state of 199 and 201 mercury isotopes using a relativistic high-precision all-order method that combines the configuration interaction and the coupled-cluster approaches. Our values g (199Hg) =-0.9485 (49 ) ×10-3 and g (201Hg) =0.3504 (18 ) ×10-3 are in agreement with the experimental measurements within the 0.5% theoretical uncertainty. We also calculate the hyperfine quenching rate of the 6 s 6 p 3P0 state in 199Hg and 201Hg and determine its lifetime to be 1.3 and 1.9 s, respectively.

  20. The g factor of the lowest 7+ state in100Rh and 6- state in104Rh

    NASA Astrophysics Data System (ADS)

    Bizzeti-Sona, A. M.; Blasi, P.; Donvito, M.; Stefanini, A. A.; Bazzacco, D.; Brandolini, F.; Löwenich, K.; Pavan, P.; Rossi-Alvarez, C.; de Poli, M.; Haque, A. M. I.

    1990-12-01

    The g-factor of the 7+ state in100Rh with T 1/2=140(5) ns and of the 6- state in104Rh with T 1/2=47(3)ns has been measured by the time-differential perturbed γ-ray angular distribution method (TDPAD). The obtained values are +0.67(2) and +0.33(1) respectively. The two nuclei were populated with reactions induced by7Li on96,100Mo at a bombarding energy of 30 MeV. Shell model calculations using effective single particle moments show that the 7+ state in100Rh has mostly a π g 9/2 ⊗ v d 5/2 configuration, while the main component of the 6- state in104Rh is the π g 9/2 ⊗ v h 11/2.

  1. Distance measurements between paramagnetic centers and a planar object by matrix Mims electron nuclear double resonance

    NASA Astrophysics Data System (ADS)

    Zänker, Paul-Philipp; Jeschke, Gunnar; Goldfarb, Daniella

    2005-01-01

    Frequency-domain electron nuclear double resonance (ENDOR), two time-domain electron nuclear double resonance techniques, and electron spin echo envelope modulation spectroscopy are compared with respect to their merit in measurements of small hyperfine couplings to nuclei with intermediate gyromagnetic ratio such as 31P. The frequency-domain Mims ENDOR experiment is found to provide the most faithful line shapes. In the limit of long electron-nuclear distances of more than 0.5 nm, sensitivity of this experiment is optimized by matching the first interpulse delay to the transverse relaxation time of the electron spins. In the same limit, Mims ENDOR efficiency scales inversely with the sixth power of distance. Hyperfine splittings as small as 33 kHz can be detected, corresponding to an electron-31P distance of 1 nm. In systems, where a certain kind of nuclei is distributed in a plane, measurements of intermolecular hyperfine couplings can be analyzed in terms of a distance of closest approach of a paramagnetic center to that plane. By applying this technique to spin-labeled lipids in a fully hydrated lipid bilayer it is found that for a fraction of lipids, chain tilt angles can be 25° larger than the mean tilt angle of the lipid chains. This model of all-trans hydrocarbon chains with a broad distribution of tilt angles is also consistent with orientation selection effects in high-field ENDOR spectra.

  2. Distance measurements between paramagnetic centers and a planar object by matrix Mims electron nuclear double resonance.

    PubMed

    Zänker, Paul-Philipp; Jeschke, Gunnar; Goldfarb, Daniella

    2005-01-08

    Frequency-domain electron nuclear double resonance (ENDOR), two time-domain electron nuclear double resonance techniques, and electron spin echo envelope modulation spectroscopy are compared with respect to their merit in measurements of small hyperfine couplings to nuclei with intermediate gyromagnetic ratio such as 31P. The frequency-domain Mims ENDOR experiment is found to provide the most faithful line shapes. In the limit of long electron-nuclear distances of more than 0.5 nm, sensitivity of this experiment is optimized by matching the first interpulse delay to the transverse relaxation time of the electron spins. In the same limit, Mims ENDOR efficiency scales inversely with the sixth power of distance. Hyperfine splittings as small as 33 kHz can be detected, corresponding to an electron-31P distance of 1 nm. In systems, where a certain kind of nuclei is distributed in a plane, measurements of intermolecular hyperfine couplings can be analyzed in terms of a distance of closest approach of a paramagnetic center to that plane. By applying this technique to spin-labeled lipids in a fully hydrated lipid bilayer it is found that for a fraction of lipids, chain tilt angles can be 25 degrees larger than the mean tilt angle of the lipid chains. This model of all-trans hydrocarbon chains with a broad distribution of tilt angles is also consistent with orientation selection effects in high-field ENDOR spectra. 2005 American Institute of Physics.

  3. Exchange enhancement of the g factor in InAs/AlSb heterostructures

    SciTech Connect

    Aleshkin, V. Ya.; Gavrilenko, V. I.; Ikonnikov, A. V.; Krishtopenko, S. S.; Sadofyev, Yu. G.; Spirin, K. E.

    2008-07-15

    The evolution of the Shubnikov-de Haas oscillations in InAs/AlSb heterostructures with twodimensional electron gas in InAs quantum wells 12-18 nm wide with considerable variation in the electron concentration (3-8) x 10{sup 11} cm{sup -2} due to the effect of negative persistent photoconductivity is studied. The values of the effective Lande factor for electrons g* = -(15-35) are determined. It is shown that the value of the g* factor increases as the quantum well width increases.

  4. Effective Mass and g Factor of Four-Flux-Quanta Composite Fermions

    SciTech Connect

    Yeh, A.S.; Tsui, D.C.; Stormer, H.L.; Pfeiffer, L.N.; Baldwin, K.W.; West, K.W.; Stormer, H.L.; Tsui, D.C.

    1999-01-01

    We investigate the properties of composite fermions with four attached flux quanta through tilted-field experiments near Landau level filling factor {nu}=3/4 . The observed collapse of fractional quantum Hall gaps in the vicinity of this quarter-filling state can be comprehensively understood in terms of composite fermions with mass and spin. Remarkably, the effective mass and g factor of these four-flux-quanta composite fermions around {nu}=3/4 are very similar to those of two-flux-quanta composite fermions around {nu}=3/2 . {copyright} {ital 1999} {ital The American Physical Society }

  5. Uncertainty quantification for nuclear density functional theory and information content of new measurements

    DOE PAGES

    McDonnell, J. D.; Schunck, N.; Higdon, D.; ...

    2015-03-24

    Statistical tools of uncertainty quantification can be used to assess the information content of measured observables with respect to present-day theoretical models, to estimate model errors and thereby improve predictive capability, to extrapolate beyond the regions reached by experiment, and to provide meaningful input to applications and planned measurements. To showcase new opportunities offered by such tools, we make a rigorous analysis of theoretical statistical uncertainties in nuclear density functional theory using Bayesian inference methods. By considering the recent mass measurements from the Canadian Penning Trap at Argonne National Laboratory, we demonstrate how the Bayesian analysis and a direct least-squaresmore » optimization, combined with high-performance computing, can be used to assess the information content of the new data with respect to a model based on the Skyrme energy density functional approach. Employing the posterior probability distribution computed with a Gaussian process emulator, we apply the Bayesian framework to propagate theoretical statistical uncertainties in predictions of nuclear masses, two-neutron dripline, and fission barriers. Overall, we find that the new mass measurements do not impose a constraint that is strong enough to lead to significant changes in the model parameters. In addition, the example discussed in this study sets the stage for quantifying and maximizing the impact of new measurements with respect to current modeling and guiding future experimental efforts, thus enhancing the experiment-theory cycle in the scientific method.« less

  6. Uncertainty quantification for nuclear density functional theory and information content of new measurements

    SciTech Connect

    McDonnell, J. D.; Schunck, N.; Higdon, D.; Sarich, J.; Wild, S. M.; Nazarewicz, W.

    2015-03-24

    Statistical tools of uncertainty quantification can be used to assess the information content of measured observables with respect to present-day theoretical models, to estimate model errors and thereby improve predictive capability, to extrapolate beyond the regions reached by experiment, and to provide meaningful input to applications and planned measurements. To showcase new opportunities offered by such tools, we make a rigorous analysis of theoretical statistical uncertainties in nuclear density functional theory using Bayesian inference methods. By considering the recent mass measurements from the Canadian Penning Trap at Argonne National Laboratory, we demonstrate how the Bayesian analysis and a direct least-squares optimization, combined with high-performance computing, can be used to assess the information content of the new data with respect to a model based on the Skyrme energy density functional approach. Employing the posterior probability distribution computed with a Gaussian process emulator, we apply the Bayesian framework to propagate theoretical statistical uncertainties in predictions of nuclear masses, two-neutron dripline, and fission barriers. Overall, we find that the new mass measurements do not impose a constraint that is strong enough to lead to significant changes in the model parameters. As a result, the example discussed in this study sets the stage for quantifying and maximizing the impact of new measurements with respect to current modeling and guiding future experimental efforts, thus enhancing the experiment-theory cycle in the scientific method.

  7. Uncertainty quantification for nuclear density functional theory and information content of new measurements

    SciTech Connect

    McDonnell, J. D.; Schunck, N.; Higdon, D.; Sarich, J.; Wild, S. M.; Nazarewicz, W.

    2015-03-24

    Statistical tools of uncertainty quantification can be used to assess the information content of measured observables with respect to present-day theoretical models, to estimate model errors and thereby improve predictive capability, to extrapolate beyond the regions reached by experiment, and to provide meaningful input to applications and planned measurements. To showcase new opportunities offered by such tools, we make a rigorous analysis of theoretical statistical uncertainties in nuclear density functional theory using Bayesian inference methods. By considering the recent mass measurements from the Canadian Penning Trap at Argonne National Laboratory, we demonstrate how the Bayesian analysis and a direct least-squares optimization, combined with high-performance computing, can be used to assess the information content of the new data with respect to a model based on the Skyrme energy density functional approach. Employing the posterior probability distribution computed with a Gaussian process emulator, we apply the Bayesian framework to propagate theoretical statistical uncertainties in predictions of nuclear masses, two-neutron dripline, and fission barriers. Overall, we find that the new mass measurements do not impose a constraint that is strong enough to lead to significant changes in the model parameters. In addition, the example discussed in this study sets the stage for quantifying and maximizing the impact of new measurements with respect to current modeling and guiding future experimental efforts, thus enhancing the experiment-theory cycle in the scientific method.

  8. Uncertainty quantification for nuclear density functional theory and information content of new measurements.

    PubMed

    McDonnell, J D; Schunck, N; Higdon, D; Sarich, J; Wild, S M; Nazarewicz, W

    2015-03-27

    Statistical tools of uncertainty quantification can be used to assess the information content of measured observables with respect to present-day theoretical models, to estimate model errors and thereby improve predictive capability, to extrapolate beyond the regions reached by experiment, and to provide meaningful input to applications and planned measurements. To showcase new opportunities offered by such tools, we make a rigorous analysis of theoretical statistical uncertainties in nuclear density functional theory using Bayesian inference methods. By considering the recent mass measurements from the Canadian Penning Trap at Argonne National Laboratory, we demonstrate how the Bayesian analysis and a direct least-squares optimization, combined with high-performance computing, can be used to assess the information content of the new data with respect to a model based on the Skyrme energy density functional approach. Employing the posterior probability distribution computed with a Gaussian process emulator, we apply the Bayesian framework to propagate theoretical statistical uncertainties in predictions of nuclear masses, two-neutron dripline, and fission barriers. Overall, we find that the new mass measurements do not impose a constraint that is strong enough to lead to significant changes in the model parameters. The example discussed in this study sets the stage for quantifying and maximizing the impact of new measurements with respect to current modeling and guiding future experimental efforts, thus enhancing the experiment-theory cycle in the scientific method.

  9. Isotopic abundance measurements on solid nuclear-type samples by glow discharge mass spectrometry.

    PubMed

    Betti, M; Rasmussen, G; Koch, L

    1996-07-01

    A double-focusing Glow Discharge Mass Spectrometer (GDMS) installed in a glovebox for nuclear sample screening has been employed for isotopic measurements. Isotopic compositions of zirconium, silicon, lithium, boron, uranium and plutonium which are elements of nuclear concern have been determined. Interferences arising from the matrix sample and the discharge gas (Ar) for each of these elements are discussed. The GDMS results are compared with those from Thermal Ionization Mass Spectrometry (TIMS). For boron and lithium at microg/g-ng/g levels, the two methods gave results in good agreement. In samples containing uranium the isotopic composition obtained by GDMS was in agreement with those from TIMS independently of the enrichment. Attempts for the determination of plutonium isotopic composition were also made. In this case, due to the interferences of uranium at mass 238 and americium at mass 241, the GDMS raw data are complementary with those values obtained from physical non-destructive techniques.

  10. Measurement of the nuclear multiplicity ratio for Ks0 hadronization at CLAS

    NASA Astrophysics Data System (ADS)

    Daniel, A.; Hicks, K.; Brooks, W. K.; Hakobyan, H.; Adhikari, K. P.; Adikaram, D.; Aghasyan, M.; Amarian, M.; Anghinolfi, M.; Avakian, H.; Baghdasaryan, H.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Bennett, R. P.; Biselli, A. S.; Bookwalter, C.; Briscoe, W. J.; Burkert, V. D.; Carman, D. S.; Casey, L.; Celentano, A.; Chandavar, S.; Cole, P. L.; Contalbrigo, M.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Dey, B.; Dickson, R.; Djalali, C.; Dodge, G. E.; Doughty, D.; Egiyan, H.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Fegan, S.; Gabrielyan, M. Y.; Gevorgyan, N.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guo, L.; Hanretty, C.; Heddle, D.; Holtrop, M.; Hyde, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jawalkar, S. S.; Jo, H. S.; Joo, K.; Kalantarians, N.; Keller, D.; Khandaker, M.; Khetarpal, P.; Kim, A.; Kim, W.; Klein, A.; Klein, F. J.; Kubarovsky, V.; Kuleshov, S. V.; Kuznetsov, V.; Lu, H. Y.; MacGregor, I. J. D.; Mao, Y.; Markov, N.; Mayer, M.; McAndrew, J.; McKinnon, B.; Meyer, C. A.; Mineeva, T.; Mirazita, M.; Mokeev, V.; Moutarde, H.; Munevar, E.; Nadel-Turonski, P.; Ni, A.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Paolone, M.; Pappalardo, L.; Paremuzyan, R.; Park, K.; Park, S.; Pasyuk, E.; Anefalos Pereira, S.; Phelps, E.; Pisano, S.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Procureur, S.; Protopopescu, D.; Raue, B. A.; Ricco, G.; Rimal, D.; Ripani, M.; Rosner, G.; Rossi, P.; Sabatié, F.; Saini, M. S.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seraydaryan, H.; Sharabian, Y. G.; Smith, G. D.; Sober, D. I.; Sokhan, D.; Stepanyan, S. S.; Stepanyan, S.; Strauch, S.; Taiuti, M.; Tang, W.; Taylor, C. E.; Tkachenko, S.; Ungaro, M.; Vernarsky, B.; Vineyard, M. F.; Voskanyan, H.; Voutier, E.; Watts, D. P.; Weinstein, L. B.; Weygand, D. P.; Wood, M. H.; Zana, L.; Zachariou, N.; Zhao, B.; Zhao, Z. W.

    2011-11-01

    The influence of cold nuclear matter on lepto-production of hadrons in semi-inclusive deep inelastic scattering is measured using the CLAS detector in Hall B at Jefferson Lab and a 5.014 GeV electron beam. We report the Ks0 multiplicity ratios for targets of C, Fe, and Pb relative to deuterium as a function of the fractional virtual photon energy z transferred to the Ks0 and the transverse momentum squared pT2 of the Ks0. We find that the multiplicity ratios for Ks0 are reduced in the nuclear medium at high z and low pT2, with a trend for the Ks0 transverse momentum to be broadened in the nucleus for large pT2.

  11. Measurement of the nuclear multiplicity ratio or image hadronization K0s at CLAS

    DOE PAGES

    Daniel, A.; Hicks, K.; Brooks, W. K.; ...

    2011-11-01

    The influence of cold nuclear matter on lepto-production of hadrons in semi-inclusive deep inelastic scattering is measured using the CLAS detector in Hall B at Jefferson Lab and a 5.014 GeV electron beam. We report the K0s multiplicity ratios for targets of C, Fe, and Pb relative to deuterium as a function of the fractional virtual photon energy z transferred to the K0sand the transverse momentum squared p2T of the K0s. We find that the multiplicity ratios for K0s are reduced in the nuclear medium at high z and low p2T, with a trend for the K0s transverse momentum tomore » be broadened in the nucleus for large p2T.« less

  12. Measurement of conductivity and permittivity on samples sealed in nuclear magnetic resonance tubes

    SciTech Connect

    Huang, W.; Angell, C. A.; Yarger, J. L.; Richert, R.

    2013-07-15

    We present a broadband impedance spectroscopy instrument designed to measure conductivity and/or permittivity for samples that are sealed in glass tubes, such as the standard 5 mm tubes used for nuclear magnetic resonance experiments. The calibrations and corrections required to extract the dielectric properties of the sample itself are outlined. It is demonstrated that good estimates of the value of dc-conductivity can be obtained even without correcting for the effects of glass or air on the overall impedance. The approach is validated by comparing data obtained from samples sealed in nuclear magnetic resonance tubes with those from standard dielectric cells, using glycerol and butylmethylimidazolium-hexafluorophosphate as respective examples of a molecular and an ionic liquid. This instrument and approach may prove useful for other studies of permittivity and conductivity where contact to the metal electrodes or to the ambient atmosphere needs to be avoided.

  13. Cooperative measures to support the Indo-Pak Agreement Reducing Risk from Accidents Relating to Nuclear Weapons.

    SciTech Connect

    Mishra, Sitakanta; Ahmed, Mansoor

    2014-04-01

    In 2012, India and Pakistan reaffirmed the Agreement on Reducing the Risk from Accidents Relating to Nuclear Weapons. Despite a history of mutual animosity and persistent conflict between the two countries, this agreement derives strength from a few successful nuclear confidence building measures that have stood the test of time. It also rests on the hope that the region would be spared a nuclear holocaust from an accidental nuclear weapon detonation that might be misconstrued as a deliberate use of a weapon by the other side. This study brings together two emerging strategic analysts from South Asia to explore measures to support the Agreement and further develop cooperation around this critical issue. This study briefly dwells upon the strategic landscape of nuclear South Asia with the respective nuclear force management structures, doctrines, and postures of India and Pakistan. It outlines the measures in place for the physical protection and safety of nuclear warheads, nuclear materials, and command and control mechanisms in the two countries, and it goes on to identify the prominent, emerging challenges posed by the introduction of new weapon technologies and modernization of the respective strategic forces. This is followed by an analysis of the agreement itself leading up to a proposed framework for cooperative measures that might enhance the spirit and implementation of the agreement.

  14. Nuclear heating measurements by in-pile calorimetry: prospective works for a microsensor design

    SciTech Connect

    Reynard-Carette, C.; Carette, M.; Aguir, K.; Bendahan, M.; Fiorido, T.; Lyoussi, A.; Fourmentel, D.; Villard, J.F.; Barthes, M.; Lanzetta, F.; Layes, G.; Vives, S.

    2015-07-01

    Since 2009 works have been performed in the framework of joint research programs between CEA and Aix-Marseille University. The main aim of these programs is to design and develop in-pile instrumentations, advanced calibration procedure and accurate measurement methods in particular for the new Material Testing Reactor (MTR) under construction in the South of France: Jules Horowitz Reactor (JHR). One major sensor is a specific radiometric calorimeter, which was studied out-of-pile from a thermal point of view and in-pile during irradiation campaigns. This sensor type is dedicated to measurements of nuclear heating (energy deposition rate per mass unit induced by interactions between nuclear rays and matter) inside experimental channels of MTRs. This kind of in-pile calorimeter corresponds to heat flux calorimeter exchanging with the external cooling fluid. This thermal running mode allows the establishment of steady thermal conditions inside the sensor to carry out online continuous measurements inside the reactor (core or reflector). Two main types of calorimeters exist. The first type consists of a single cell calorimeter. It is divided into a sample of material to be tested and a jacket instrumented with two thermocouples or a single thermocouple (Gamma Thermometer). The second, called a differential calorimeter, is composed of two superposed twin cells (a measurement cell containing a sample of material, and a reference cell to remove the heating of the cell body) instrumented with four thermocouples and two electrical heaters. Contrary to a single-cell calorimeter, a differential calorimeter allows the compensation of the parasite nuclear heating of the sensor body or jacket. Moreover, it possesses interesting advantages: thanks to the heaters embedded in the cells, three different measurement methods can be applied during irradiations to quantify nuclear heating. The first one is based on the use of out-of-pile calibration curves obtained by generating a heat

  15. Accurate Measurement of Velocity and Acceleration of Seismic Vibrations near Nuclear Power Plants

    NASA Astrophysics Data System (ADS)

    Arif, Syed Javed; Imdadullah; Asghar, Mohammad Syed Jamil

    In spite of all prerequisite geological study based precautions, the sites of nuclear power plants are also susceptible to seismic vibrations and their consequent effects. The effect of the ongoing nuclear tragedy in Japan caused by an earthquake and its consequent tsunami on March 11, 2011 is currently beyond contemplations. It has led to a rethinking on nuclear power stations by various governments around the world. Therefore, the prediction of location and time of large earthquakes has regained a great importance. The earth crust is made up of several wide, thin and rigid plates like blocks which are in constant motion with respect to each other. A series of vibrations on the earth surface are produced by the generation of elastic seismic waves due to sudden rupture within the plates during the release of accumulated strain energy. The range of frequency of seismic vibrations is from 0 to 10 Hz. However, there appears a large variation in magnitude, velocity and acceleration of these vibrations. The response of existing or conventional methods of measurement of seismic vibrations is very slow, which is of the order of tens of seconds. A systematic and high resolution measurement of velocity and acceleration of these vibrations are useful to interpret the pattern of waves and their anomalies more accurately, which are useful for the prediction of an earthquake. In the proposed work, a fast rotating magnetic field (RMF) is used to measure the velocity and acceleration of seismic vibrations in the millisecond range. The broad spectrum of pulses within one second range, measured by proposed method, gives all possible values of instantaneous velocity and instantaneous acceleration of the seismic vibrations. The spectrum of pulses in millisecond range becomes available which is useful to measure the pattern of fore shocks to predict the time and location of large earthquakes more accurately. Moreover, instead of average, the peak values of these quantities are helpful

  16. 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.

  17. Attempts to develop a new nuclear measurement technique of β-glucuronidase levels in biological samples

    NASA Astrophysics Data System (ADS)

    Ünak, T.; Avcibasi, U.; Yildirim, Y.; Çetinkaya, B.

    2003-01-01

    β-Glucuronidase is one of the most important hydrolytic enzymes in living systems and plays an essential role in the detoxification pathway of toxic materials incorporated into the metabolism. Some organs, especially liver and some tumour tissues, have high level of β-glucuronidase activity. As a result the enzymatic activity of some kind of tumour cells, the radiolabelled glucuronide conjugates of cytotoxic, as well as radiotoxic compounds have potentially very valuable diagnostic and therapeutic applications in cancer research. For this reason, a sensitive measurement of β-glucuronidase levels in normal and tumour tissues is a very important step for these kinds of applications. According to the classical measurement method of β-glucuronidase activity, in general, the quantity of phenolphthalein liberated from its glucuronide conjugate, i.e. phenolphthalein-glucuronide, by β-glucuronidase has been measured by use of the spectrophotometric technique. The lower detection limit of phenolphthalein by the spectrophotometric technique is about 1 3 μg. This means that the β-glucuronidase levels could not be detected in biological samples having lower levels of β-glucuronidase activity and therefore the applications of the spectrophotometric technique in cancer research are very seriously limited. Starting from this consideration, we recently attempted to develop a new nuclear technique to measure much lower concentrations of β-glucuronidase in biological samples. To improve the detection limit, phenolphthalein-glucuronide and also phenyl-N-glucuronide were radioiodinated with 131I and their radioactivity was measured by use of the counting technique. Therefore, the quantity of phenolphthalein or aniline radioiodinated with 131I and liberated by the deglucuronidation reactivity of β-glucuronidase was used in an attempt to measure levels lower than the spectrophotometric measurement technique. The results obtained clearly verified that 0.01 pg level of

  18. Attempts to develop a new nuclear measurement technique of β-glucuronidase levels in biological samples

    NASA Astrophysics Data System (ADS)

    Ünak, T.; Avcibasi, U.; Yildirim, Y.; Çetinkaya, B.

    2003-01-01

    β-Glucuronidase is one of the most important hydrolytic enzymes in living systems and plays an essential role in the detoxification pathway of toxic materials incorporated into the metabolism. Some organs, especially liver and some tumour tissues, have high level of β-glucuronidase activity. As a result the enzymatic activity of some kind of tumour cells, the radiolabelled glucuronide conjugates of cytotoxic, as well as radiotoxic compounds have potentially very valuable diagnostic and therapeutic applications in cancer research. For this reason, a sensitive measurement of β-glucuronidase levels in normal and tumour tissues is a very important step for these kinds of applications. According to the classical measurement method of β-glucuronidase activity, in general, the quantity of phenolphthalein liberated from its glucuronide conjugate, i.e. phenolphthalein-glucuronide, by β-glucuronidase has been measured by use of the spectrophotometric technique. The lower detection limit of phenolphthalein by the spectrophotometric technique is about 1-3 μg. This means that the β-glucuronidase levels could not be detected in biological samples having lower levels of β-glucuronidase activity and therefore the applications of the spectrophotometric technique in cancer research are very seriously limited. Starting from this consideration, we recently attempted to develop a new nuclear technique to measure much lower concentrations of β-glucuronidase in biological samples. To improve the detection limit, phenolphthalein-glucuronide and also phenyl-N-glucuronide were radioiodinated with 131I and their radioactivity was measured by use of the counting technique. Therefore, the quantity of phenolphthalein or aniline radioiodinated with 131I and liberated by the deglucuronidation reactivity of β-glucuronidase was used in an attempt to measure levels lower than the spectrophotometric measurement technique. The results obtained clearly verified that 0.01 pg level of

  19. The alpha and beta emitter measurement system in INER. Institute of Nuclear Energy Research.

    PubMed

    Wuu, Jyi-Lan; Yuan, Ming-Chen; Su, Shi-Hwa; Hwang, Wen-Son

    2002-01-01

    An alpha/beta emitter measurement system used to calibrate surface sources following the guidelines of ISO 8769 has been established in Institute of Nuclear Energy Research (INER) around the year 2000. This system consists of a windowless proportional counter with a uniformity of 0.28% when measuring the emission rate of a source on a centered area of 100 mm x 150 mm, and a uniformity of 0.62% when the source area was 150 mm x 200 mm. Four 100 mm x 150 mm sources (90Sr + 90Y, 36Cl, 14C and 241Am) had been measured by this system. The measurement results of the above four sources when compared with those of National Physical Laboratory, UK (NPL) showed difference between the two laboratories of < 1%.

  20. Impact of the Fukushima nuclear accident on background radiation doses measured by control dosimeters in Japan.

    PubMed

    Romanyukha, Alexander; King, David L; Kennemur, Lisa K

    2012-05-01

    After the 9.0 magnitude earthquake and subsequent massive tsunami on 11 March 2011 in Japan, several reactors at the Fukushima Daiichi Nuclear Power Plant suffered severe damage. There was immediate participation of U.S. Navy vessels and other United States Department of Defense (DoD) teams that were already in the area at the time of the disaster or arrived shortly thereafter. The correct determination of occupational dose equivalent requires estimation of the background dose component measured by control dosimeters, which is subsequently subtracted from the total dose equivalent measured by personal dosimeters. The purpose of the control dosimeters is to determine the amount of radiation dose equivalent that has accumulated on the dosimeter from background or other non-occupational sources while they are in transit or being stored. Given the release of radioactive material and potential exposure to radiation from the Fukushima Daiichi Nuclear Power Plant and the process by which the U.S. Navy calculates occupational exposure to ionizing radiation, analysis of pre- and post-event control dosimeters is warranted. Several hundred historical dose records from the Naval Dosimetry Center (NDC) database were analyzed and compared with the post-accident dose equivalent data of control dosimeters. As result, it was shown that the dose contribution of the radiation and released radiological materials from the Fukushima nuclear accident to background radiation doses is less than 0.375 μSv d for shallow and deep photon dose equivalent. There is no measurable effect on neutron background exposure. The latter has at least two important conclusions. First, the NDC can use doses measured by control dosimeters at issuing sites in Japan for determination of personnel dose equivalents; second, the dose data from control dosimeters prior to and after the Fukushima accident may be used to assist in dose reconstruction of non-radiological (non-badged) personnel at these locations.

  1. The permanent electric dipole moments and magnetic g factors of uranium monoxide

    NASA Astrophysics Data System (ADS)

    Heaven, Michael C.; Goncharov, Vasiliy; Steimle, Timothy C.; Ma, Tongmei; Linton, Colan

    2006-11-01

    Permanent electric dipole moments and magnetic g factors for uranium monoxide (UO) have been determined from analyses of optical Stark and Zeeman spectra recorded at a spectral resolution that approaches the natural linewidth limit. Numerous branch features in the previously characterized [L. A. Kaledin et al., J. Mol. Spectrosc. 164, 27 (1994)] (0,0) [18403]5-X(1)4 and (0,0) [18404]5-X(1)4 electronic transitions were recorded in the presence of tunable static electric (Stark effect) or magnetic (Zeeman effect) fields. The lines exhibited unusually large Zeeman tuning effects. A ligand field model and an ab initio electronic structure calculation [R. Tyagi, Ph.D. thesis, The Ohio State University (2005)] were used to interpret the ground state properties. The results indicate that the low energy electronic states of UO are sufficiently ionic for the meaningful application of ligand field theory models. The dipole moments and g factors were distinctly different for the three electronic states examined, which implies that these properties may be used to deduce the underlying electronic state configurations.

  2. 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].

  3. Measurement of the true transverse nuclear magnetic resonance relaxation in the presence of field gradients.

    PubMed

    Mitchell, J; Chandrasekera, T C; Gladden, L F

    2013-08-21

    A measure of the nuclear spin transverse relaxation time T2, as determined using the nuclear magnetic resonance Carr-Purcell Meiboom-Gill (CPMG) experiment, provides unique information characterizing the microstructure of porous media which are themselves ubiquitous across fields of petrophysics, biophysics, and chemical engineering. However, the CPMG measurement is sensitive to diffusion in large magnetic field gradients. Under such conditions an effective relaxation time T2,eff is observed instead, described by a combination of relaxation and diffusion exponents. The relaxation exponent always varies as nte (where n is the number, and te is the temporal separation, of spin echoes). The diffusion exponent varies as nte (k), where 1 < k ≤ 3, although the exact analytic form is often unknown. Here we present a general approach to separating the influence of relaxation and diffusion by utilizing a composite diffusion exponent. Any T2,eff component with a power of k > 1 is removed to provide a measure of the true T2 relaxation time distribution from CPMG data acquired in the presence of a strong background gradient. We apply the technique to discriminate between the effects of relaxation and diffusion in porous media using catalysts and rocks as examples. The method is generally applicable to any CPMG measurements conducted in the presence of a static magnetic field gradient.

  4. On-site gamma-ray spectroscopic measurements of fission gas release in irradiated nuclear fuel.

    PubMed

    Matsson, I; Grapengiesser, B; Andersson, B

    2007-01-01

    An experimental, non-destructive in-pool, method for measuring fission gas release (FGR) in irradiated nuclear fuel has been developed. Using the method, a significant number of experiments have been performed in-pool at several nuclear power plants of the BWR type. The method utilises the 514 keV gamma-radiation from the gaseous fission product (85)Kr captured in the fuel rod plenum volume. A submergible measuring device (LOKET) consisting of an HPGe-detector and a collimator system was utilised allowing for single rod measurements on virtually all types of BWR fuel. A FGR database covering a wide range of burn-ups (up to average rod burn-up well above 60 MWd/kgU), irradiation history, fuel rod position in cross section and fuel designs has been compiled and used for computer code benchmarking, fuel performance analysis and feedback to reactor operators. Measurements clearly indicate the low FGR in more modern fuel designs in comparison to older fuel types.

  5. Lande g-factor in semiconductor cylinder quantum dots under magnetic fields and spin-orbit interaction

    NASA Astrophysics Data System (ADS)

    Gharaati, Abdolrasoul

    2017-05-01

    In this paper, the electron effective Lande g-factor in semiconductor cylinder quantum dots is studied in the presence of the Rashba spin-orbit effect and an applied magnetic field parallel to the cylinder axis. For this goal, I have obtained an analytical solution to one-particle Schrodinger equation in the presence of both magnetic field and spin-orbit interaction (SOI). Then, using the obtained energy levels, I have study the electron effective Lande g-factor. It is found that: It is found that (i) energy levels strongly depend on the combined effects of external magnetic field and spin-orbit interaction strength. (ii) The effective Lande g-factor decreases when magnetic field increases. (iii) By increasing the cylinder radius ρ, the electron g-factor decreases. (iv) By increasing the strength of SOI, the electron g-factor increases.

  6. Dose rate measurements from radiopharmaceuticals: implications for nuclear medicine staff and for children with radioactive parents.

    PubMed

    Greaves, C D; Tindale, W B

    1999-02-01

    Following the introduction of a number of radiopharmaceuticals, we assessed the dose received by staff working in the nuclear medicine department and also by children who may be in close contact with a radioactive parent. We measured departure dose rates (microSv.h-1) at distances of 0.1, 0.5 and 1.0 m from the skin surface at the level of the thyroid, chest and bladder of patients undergoing the following nuclear medicine procedures: MUGA scans using 99Tcm-labelled red blood cells, myocardial perfusion scans using 99Tcm-labelled radiopharmaceuticals, lymphoscintigraphy using colloidal 99Tcm (Re) sulphide, bone scans using 99Tcm-labelled oxidronate, 111In-octreotide scans, 111In-labelled leukocyte studies and cardiac reinjection studies using 201Tl. The maximum dose rates at 0.1 m were those from MUGA studies (167.3 microSv.h-1) and myocardial perfusion studies (one-day protocol = 391.7 microSv.h-1, two-day protocol = 121.8 microSv.h-1). The implications of these dose rates on both technical and nursing staff are assessed. Also, the dose received by an infant in close contact with a parent following a nuclear medicine investigation was estimated.

  7. Nuclear magnetic resonance measurement of ammonia diffusion in dense solid-liquid slurries. Revision 1

    SciTech Connect

    Bobroff, S.; Phillips, R.J.; Shekarriz, A.

    1998-01-01

    The flammability and toxicity of ammonia released from the nuclear waste tanks at Hanford have been the subject of several recent studies. These releases may occur episodically, such as the buoyant plume releases occurring in various double-shell tanks (DSTs); gradually through the surface of the waste; or from the partially saturated saltcakes in the single-shell tanks during salt-well pumping. The diffusion of ammonium ions in aqueous solutions was measured by nuclear magnetic resonance (NMR) using the pulsed field gradient (PFG) method. The ammonium ions were obtained from aqueous solutions of ammonium chloride, ammonium sulfate, ammonium bicarbonate, and ammonium hydroxide. The translational diffusion of the ammonium ions was determined by measuring the diffusion of nitrogen nuclei in solution. Results showed that the ammonium diffusion coefficient can be measured in aqueous solutions with concentrations as low as 20 {times} 10{sup {minus}3} {und M}. Typical values measured for the diffusion coefficient of the ammonium ion are 2 {times} 10{sup {minus}5} cm{sup 2}/s ({+-}10%), similar to the values found for pure water. Due to the effect of the solution pH upon the NMR relaxation parameters for {sup 14}N, measurements are constrained to pH values below 8.5. However, {sup 15}N labeled ammonia is less sensitive to the solution pH, extending the measurement range to pH of 9.5. The results show that the solution viscosity has a measurable impact on the diffusion coefficient. The diffusion coefficient is almost inversely proportional to the relative viscosity of the solution, irrespective of how the viscosity is increased. Further, a randomly-packed porous bed of 200 {micro}m PMMA resulted in a reduction of {approximately} 30% in the diffusion coefficient as a result of hindered diffusion.

  8. g-factor and quadrupole moment of the 21/2- isomeric state in 131La: Signature for a weakly-deformed magnetic rotational band head

    NASA Astrophysics Data System (ADS)

    Kaur, Jasmeet; Bansal, Neeraj; Bhati, A. K.; Kumar, R.; Sharma, Vijay R.; Kapoor, K.; Kumar, V.; Kaur, Navneet

    2017-02-01

    The g-factor and the static quadrupole moment of a magnetic rotational band head 21/2- at 2121 keV in 131La have been determined by means of the time-differential perturbed angular distribution technique. The measured value of the g-factor, + 1.060 (4), is in agreement with the theoretical value for a three quasi-proton, π3 {11/2- [ 505 ] ⊗5/2+ [ 422 ] ⊗5/2+ [ 413 ] } Nilsson configuration assignment. The observed spectroscopic quadrupole moment ratio, Qs (21/2- ,131 La)/Qs (19/2- ,137 La) = 0.457 (4), supports the collective oblate shape (γ ∼ - 60 °) with quadrupole deformation β2 < 0.07. The half-life of the 21/2- state, 37.2(1) ns, is re-measured with better accuracy.

  9. Single-molecule conductance measurements of biomolecule translocation across biomimetic nuclear pores

    NASA Astrophysics Data System (ADS)

    Dekker, Cees

    2012-02-01

    After a brief overview of our recent work on solid-state nanopores, I will present single-molecule transport data across biomimetic nanopores that contain the key regulating parts of the nuclear pore complex (NPC). The mechanism for the remarkable selectivity of NPCs has remained unclear in a large part due to difficulties in designing experiments that can probe the transport at the relevant length and time scales. Building and measuring on biomimetic NPCs provides new opportunities to address this long-standing problem. covalently tether the natively unfolded Phe-Gly rich domains (FG-domains) of human nuclear binding proteins to a solid-state nanopore (a 10-100 nm sized hole in a SiN membrane). Ionic current measurements provide a probe to monitor single molecules that traverse the pore. Translocation events are observed for transport receptors (Impβ), whereas transport of passive molecules (BSA) is found to be blocked. Interestingly, a single type of nuclear pore proteins appears already sufficient to form a selective barrier for transport. A translocation time of about 2.5 ms is measured for Impβ. This time is found to be similar for transport across Nup153 and Nup98 coated pores, although the observed ionic conductance differs between these two types of pores. We compare two simple models for the pore conductance and find, for both Nups, that the data fits best to a model with an open central channel and a condensed layer along the outer circumference of the pore. reproducing the key features of the NPC, our biomimetic approach opens the way to study a wide variety of nucleo-cytoplasmic transport processes at the single-molecule level in vitro.

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

    SciTech Connect

    Hanson, Susan Kloek; Pollington, Anthony Douglas; Waidmann, Christopher Russell; Kinman, William Scott; Wende, Allison Marie; Miller, Jeffrey L.; Berger, Jennifer A.; Oldham, Warren James; Selby, Hugh D.

    2016-07-05

    This study 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 95Zr and 97Zr. By measuring both the perturbation of the 95Mo/96Mo and 97Mo/96Mo isotopic ratios and the total amount of molybdenum in the Trinity nuclear debris samples, it is possible to calculate the original concentrations of the 95Zr and 97Zr 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.

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

    SciTech Connect

    Hanson, Susan Kloek; Pollington, Anthony Douglas; Waidmann, Christopher Russell; Kinman, William Scott; Wende, Allison Marie; Miller, Jeffrey L.; Berger, Jennifer A.; Oldham, Warren James; Selby, Hugh D.

    2016-07-05

    This study 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 95Zr and 97Zr. By measuring both the perturbation of the 95Mo/96Mo and 97Mo/96Mo isotopic ratios and the total amount of molybdenum in the Trinity nuclear debris samples, it is possible to calculate the original concentrations of the 95Zr and 97Zr 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.

  12. Comparison of calculated quantities with measured quantities for the LEU-fueled Ford Nuclear Reactor

    SciTech Connect

    Bretscher, M.M.; Snelgrove, J.L.

    1982-01-01

    The Ford Nuclear Reactor (FNR) went critical on December 8, 1981 with 23 LEU fuel elements. Five of these 23 elements were fabricated by CERCA and the others by NUKEM. Since that time a substantial data base of experimental results for LEU cores has been accumulated by the University of Michigan FNR staff. This paper compares some of the experimental data with analytical calculations based, for the most part, on three-dimensional diffusion theory. The critical configuration, control rod worths, axial rhodium reaction rate profiles and thermal flux distributions have been calculated and compared with measurements.

  13. Measuring Human Performance in Simulated Nuclear Power Plant Control Rooms Using Eye Tracking

    SciTech Connect

    Kovesdi, Casey Robert; Rice, Brandon Charles; Bower, Gordon Ross; Spielman, Zachary Alexander; Hill, Rachael Ann; LeBlanc, Katya Lee

    2015-11-01

    Control room modernization will be an important part of life extension for the existing light water reactor fleet. As part of modernization efforts, personnel will need to gain a full understanding of how control room technologies affect performance of human operators. Recent advances in technology enables the use of eye tracking technology to continuously measure an operator’s eye movement, which correlates with a variety of human performance constructs such as situation awareness and workload. This report describes eye tracking metrics in the context of how they will be used in nuclear power plant control room simulator studies.

  14. Modeling and Simulation Approaches to Developing Human Performance Measures in Nuclear Industry

    SciTech Connect

    Bruce P. Hallbert; Jeffrey C. Joe; Molly J. Keefe; Julius J. Persensky

    2007-08-01

    Human performance is a key component to the safe operation of nuclear power plants. Further, human performance is quite variable, and while some variability may be random, much of it may be attributed to factors that are difficult to assess. There is a need to identify and assess aspects of human performance that relate to plant safety and to develop measures that can be used to successfully assess human performance for purposes of research that can lead to technical basis for developing human factors review criteria.

  15. Measurement of the 14N nuclear quadrupole resonance frequencies by the solid effect

    NASA Astrophysics Data System (ADS)

    Seliger, J.; Žagar, V.

    2008-07-01

    1H- 14N nuclear quadrupole double resonance using magnetic field cycling between high and low magnetic field and solid effect in the low magnetic field is analyzed in details. The transition probabilities per unit time for the solid-effect transitions are calculated. The double resonance spectra are calculated in the limiting cases of fast and slow nitrogen spin-lattice relaxation. The double resonance spectra are measured in histamine and quinolinic acid. The experimental spectra are analyzed and the 14N NQR frequencies are determined.

  16. Measuring nuclear transparency from exclusive vector meson production in lepton-nucleus scattering

    SciTech Connect

    Fang, G.Y.

    1994-04-01

    Preliminary results on the measurement of nuclear transparencies from exclusive {rho}{sup 0} meson production from E665 at Fermilab are reported. The data were collected on hydrogen, deuterium, carbon, calcium, and lead targets with a mean beam energy of 470 GeV. Increases in the transparencies are observed in both coherent and incoherent production channels as the virtuality of the photon increases, as expected of color transparency. Ideas of systematic studies of color transparency in exclusive vector meson production at CEBAF are discussed.

  17. Sensors Synergistic With Nature For In-pile Nuclear Reactor Measurements

    SciTech Connect

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

    2012-10-01

    To be able to evolve fuel and structural microstructure within a nuclear power reactor in an engineered manner, an effective extreme environment sensor must exist. The development of sensor technology for nondestructive and nonintrusive measurements in harsh environments is a very active field. However most of the effort has been in adapting existing sensing technology to meet the harsh environmental requirements. A different approach is being presented. The fundamental question that we are trying to answer is how do we take advantage of the harsh environment and maintain synergy between the sensor and the environment. This paper will discuss the synergistic senor being developed that takes advantage of the harsh environments.

  18. Effect of Geomagnetism on 101Ru Nuclear Quadrupole Resonance Measurements of CeRu2

    NASA Astrophysics Data System (ADS)

    Manago, Masahiro; Ishida, Kenji; Matsuda, Tatsuma D.; Ōnuki, Yoshichika

    2015-11-01

    We performed 101Ru nuclear quadrupole resonance (NQR) measurements on the s-wave superconductor CeRu2 and found oscillatory behavior in the spin-echo amplitude at the | ± 1/2> ≤ftrightarrow | ± 3/2> transitions but not at the | ± 3/2> ≤ftrightarrow | ± 5/2> transitions. The modulation disappears in the superconducting state or in a magnetic shield, which implies a geomagnetic field effect. Our results indicate that the NQR spin-echo decay curve at the | ± 1/2> ≤ftrightarrow | ± 3/2> transitions is sensitive to a weak magnetic field.

  19. Measurement of the nuclear electromagnetic cascade development in glass at energies above 200 GeV

    NASA Technical Reports Server (NTRS)

    Gillespie, C. R.; Huggett, R. W.; Humphreys, D. R.; Jones, W. V.; Levit, L. B.

    1971-01-01

    The longitudinal development of nuclear-electromagnetic cascades with energies greater than 200 GeV was measured in a low-Z (glass) absorber. This was done in the course of operating an ionization spectrometer at mountain altitude in an experiment to study the properties of gamma rays emitted from individual interactions at energies around 10,000 GeV. The ionization produced by a cascade is sampled by 20 sheets of plastic scintillator spaced uniformly in depth every 2.2 radiation lengths. Adjacent pairs of scintillators are viewed by photomultipliers which measure the mean ionization produced by an individual cascade in 10 layers each 1.1 interaction length (4.4 radiation lengths) thick. The longitudinal development of the cascades was measured for about 250 cascades having energies ranging from 200 GeV to 2500 GeV. The observations are compared with the predictions of calculations made for this specific spectrometer using a three-dimensional Monte Carlo model of the nuclear-electromagnetic cascade.

  20. An accurate optical technique for measuring the nuclear polarisation of 3He gas

    NASA Astrophysics Data System (ADS)

    Talbot, C.; Batz, M.; Nacher, P.-J.; Tastevin, G.

    2011-06-01

    In the metastability exchange optical pumping cells of our on-site production unit and of our other experimental set-ups, we use a light absorption technique to measure the 3He nuclear polarisation. It involves weak probe beams at 1083 nm, that are either perpendicular or parallel to the magnetic field and cell axis, with suitable light polarisations. When metastability exchange collisions control the populations of the sublevels in the 23S state, absolute values of the 3He ground state nuclear polarisation are directly inferred from the ratio of the absorption rates measured for these probe beams. Our report focuses on the transverse detection scheme for which this ratio, measured at low magnetic field for σ and π light polarisations, hardly depends on gas pressure or the presence of an intense pump beam. This technique has been systematically tested both in pure 3He and isotopic mixtures and it is routinely used for accurate control of the optical pumping efficiency as well as for calibration of the NMR system.

  1. Back-n white neutron facility for nuclear data measurements at CSNS

    NASA Astrophysics Data System (ADS)

    An, Q.; Bai, H. Y.; Bao, J.; Cao, P.; Chen, Y.; Chen, Y. L.; Cheng, P. J.; Fan, R. R.; Feng, C. Q.; Gu, J.; Gu, M. H.; He, B.; He, G. Z.; He, W.; He, Y. C.; He, Y. F.; Huang, H. X.; Huang, X. R.; Huang, W. L.; Ji, X. L.; Ji, X. Y.; Jing, H. T.; Li, B.; Li, C. B.; Li, G.; Li, Q.; Li, Y.; Liu, R.; Liu, S. B.; Luan, G. Y.; Ma, Y. L.; Peng, M.; Ning, C. J.; Qi, X. C.; Ren, J.; Ruan, X. C.; Shi, B.; Song, Z. H.; Su, X. B.; Sun, Z. J.; Tang, H. Q.; Tang, J. Y.; Tan, Z. X.; Wang, P. C.; Wang, Q.; Wang, Q.; Wang, Yan F.; Wang, Z. H.; Wen, J.; Wen, Z. W.; Wu, Q. B.; Wu, X. G.; Yang, Y. W.; Yu, T.; Yu, Y. J.; Zhang, D. L.; Zhang, G. H.; Zhang, H. Y.; Zhang, J.; Zhang, L. Y.; Zhang, Q. W.; Zhang, X. P.; Zhang, Y. X.; Zhao, Y. T.; Zheng, L.; Zheng, Y.; Zhong, J.; Zhong, Q. P.; Zhou, L.; Zhou, Z. Y.; Zhu, K. J.

    2017-07-01

    Back-streaming neutrons through the incoming proton channel at the spallation target station of China Spallation Neutron Source (CSNS) has been exploited as a white neutron beam line (so-called Back-n), and a number of spectrometers for nuclear data measurements have been planned. With a thick tungsten target and modest moderation by the cooling water through the target slices, the neutron beam is very intense which is in the order of 5.0×106 n/cm2/s at 80 m from the target and has an excellent energy spectrum spanning from 1 eV to 100 MeV. In addition, the time structure of the primary proton beam under different accelerator operation modes is fully applicable for time-of-flight measurements. Altogether, it makes the CSNS Back-n very much suitable for nuclear data measurements. The construction of the neutron beam line and five of the seven planned spectrometers are under way. It is expected that the first batch experiments be carried out from late 2017, when CSNS starts commissioning.

  2. Recent Developments in Nuclear Data Measurement capabilities at the Gaerttner LINAC Center at RPI

    NASA Astrophysics Data System (ADS)

    Danon, Y.; Daskalakis, A.; McDermott, B.; Thompson, N.; Youmans, A.; Block, R.; Barry, D.; Epping, B.; Leinweber, G.; Rapp, M.; Donovan, T.

    2016-03-01

    The Gaerttner LINAC Center at RPI uses a 60 MeV electron linear accelerator to produce short pulses of neutrons with duration of 5-5000 ns. The main research thrust at the Center is nuclear data for nuclear reactors and criticality safety applications. The Center includes several setups for time-of-flight measurements including neutron transmission, capture and scattering detectors, and a lead slowing-down spectrometer. Experiments were designed to produce neutron interaction cross sections that cover the energy range of 0.01 eV to 20 MeV. Recently added experiments include: setups for keV and fast neutron transmission, a C6D6 detector array for keV neutron capture measurements, and a fast neutron scattering system. Results discussed here include fast neutron scattering and angular distributions for natFe, iron capture measurements for incident neutrons from 1 keV to 2 MeV, fast neutron transmission through W and H2O samples, and keV transmission through Mo isotopes.

  3. Precise measurement of the nuclear dependence of the EMC effect at large x

    NASA Astrophysics Data System (ADS)

    Daniel, Aji

    Experiment E03-103, carried out in Hall C at the Thomas Jefferson National Accelerator Facility, measuring inclusive electron scattering cross sections from nuclear targets over a broad range of x (0.3 < x < 1) up to Q2 ≈ 8 GeV 2. The bulk of the data were taken at a beam energy of 5.8 GeV, with beam currents ranging from 30 to 80 muA. This dissertation describes the experiment in detail, and presents the extracted EMC ratios for the cryogenic targets 3He, 4He and solid targets Be, C, Cu, and Au. Our data provide the first measurement of the EMC effect in 3He at x > 0.4, and improve the known precision of the existing measurements of the effect in 4He and other nuclear targets at large x. The data have also been analyzed in terms of the structure function FA2 to examine the scaling of the inelastic scattering in x and xi.

  4. A new measurement of electron transverse polarization in polarized nuclear β-decay

    NASA Astrophysics Data System (ADS)

    Kawamura, H.; Akiyama, T.; Hata, M.; Hirayama, Y.; Ikeda, M.; Ikeda, Y.; Ishii, T.; Kameda, D.; Mitsuoka, S.; Miyatake, H.; Nagae, D.; Nakaya, Y.; Ninomiya, K.; Nitta, M.; Ogawa, N.; Onishi, J.; Seitaibashi, E.; Tanaka, S.; Tanuma, R.; Totsuka, Y.; Toyoda, T.; Watanabe, Y. X.; Murata, J.

    2017-03-01

    The Mott polarimetry for T-violation (MTV) experiment tests time-reversal symmetry in polarized nuclear β-decay by measuring an electron’s transverse polarization as a form of angular asymmetry in Mott scattering using a thin metal foil. A Mott scattering analyzer system developed using a tracking detector to measure scattering angles offers better event selectivity than conventional counter experiments. In this paper, we describe a pilot experiment conducted at KEK-TRIAC using a prototype system with a polarized 8Li beam. The experiment confirmed the sound performance of our Mott analyzer system to measure T-violating triple correlation (R correlation), and therefore recommends its use in higher-precision experiments at the TRIUMF-ISAC.

  5. Demonstration of a transmission nuclear resonance fluorescence measurement for a realistic radioactive waste canister scenario

    NASA Astrophysics Data System (ADS)

    Angell, C. T.; Hajima, R.; Hayakawa, T.; Shizuma, T.; Karwowski, H. J.; Silano, J.

    2015-03-01

    Transmission nuclear resonance fluorescence (NRF) is a promising method for precision non-destructive assay (NDA) of fissile isotopes-including 239Pu-in spent fuel while inside a storage canister. The assay, however, could be confounded by the presence of overlapping resonances from competing isotopes in the canister. A measurement is needed to demonstrate that transmission NRF is unaffected by the shielding material. To this end, we carried out a transmission NRF measurement using a mono-energetic γ-ray beam on a proxy target (Al) and absorbing material simulating a realistic spent fuel storage canister. Similar amounts of material as would be found in a possible spent fuel storage canister were placed upstream: concrete, stainless steel (SS 304), lead (as a proxy for U), and water. An Al absorption target was also used as a reference. These measurements demonstrated that the canister material should not significantly influence the non-destructive assay.

  6. Direct Measurement of Nuclear Dependence of Charged Current Quasielasticlike Neutrino Interactions Using MINERvA

    NASA Astrophysics Data System (ADS)

    Betancourt, M.; Ghosh, A.; Walton, T.; Altinok, O.; Bellantoni, L.; Bercellie, A.; Bodek, A.; Bravar, A.; Cai, T.; Martinez Caicedo, D. A.; Carneiro, M. F.; Dytman, S. A.; Díaz, G. A.; Felix, J.; Fields, L.; Fine, R.; Galindo, R.; Gallagher, H.; Ghosh, A.; Golan, T.; Gran, R.; Harris, D. A.; Higuera, A.; Hurtado, K.; Kiveni, M.; Kleykamp, J.; Le, T.; Maher, E.; Manly, S.; Mann, W. A.; Marshall, C. M.; McFarland, K. S.; McGivern, C. L.; McGowan, A. M.; Messerly, B.; Miller, J.; Mislivec, A.; Morfín, J. G.; Mousseau, J.; Naples, D.; Nelson, J. K.; Norrick, A.; Nuruzzaman, Patrick, C. E.; Perdue, G. N.; Ramírez, M. A.; Ren, L.; Rimal, D.; Rodrigues, P. A.; Ruterbories, D.; Schellman, H.; Sobczyk, J. T.; Solano Salinas, C. J.; Sánchez Falero, S.; Valencia, E.; Wolcott, J.; Wospakrik, M.; Yaeggy, B.; Minerva Collaboration

    2017-08-01

    Charged-current νμ interactions on carbon, iron, and lead with a final state hadronic system of one or more protons with zero mesons are used to investigate the influence of the nuclear environment on quasielasticlike interactions. The transferred four-momentum squared to the target nucleus, Q2, is reconstructed based on the kinematics of the leading proton, and differential cross sections versus Q2 and the cross-section ratios of iron, lead, and carbon to scintillator are measured for the first time in a single experiment. The measurements show a dependence on the atomic number. While the quasielasticlike scattering on carbon is compatible with predictions, the trends exhibited by scattering on iron and lead favor a prediction with intranuclear rescattering of hadrons accounted for by a conventional particle cascade treatment. These measurements help discriminate between different models of both initial state nucleons and final state interactions used in the neutrino oscillation experiments.

  7. Direct Measurement of Nuclear Dependence of Charged Current Quasielasticlike Neutrino Interactions Using MINERvA.

    PubMed

    Betancourt, M; Ghosh, A; Walton, T; Altinok, O; Bellantoni, L; Bercellie, A; Bodek, A; Bravar, A; Cai, T; Martinez Caicedo, D A; Carneiro, M F; Dytman, S A; Díaz, G A; Felix, J; Fields, L; Fine, R; Galindo, R; Gallagher, H; Ghosh, A; Golan, T; Gran, R; Harris, D A; Higuera, A; Hurtado, K; Kiveni, M; Kleykamp, J; Le, T; Maher, E; Manly, S; Mann, W A; Marshall, C M; McFarland, K S; McGivern, C L; McGowan, A M; Messerly, B; Miller, J; Mislivec, A; Morfín, J G; Mousseau, J; Naples, D; Nelson, J K; Norrick, A; Nuruzzaman; Patrick, C E; Perdue, G N; Ramírez, M A; Ren, L; Rimal, D; Rodrigues, P A; Ruterbories, D; Schellman, H; Sobczyk, J T; Solano Salinas, C J; Sánchez Falero, S; Valencia, E; Wolcott, J; Wospakrik, M; Yaeggy, B

    2017-08-25

    Charged-current ν_{μ} interactions on carbon, iron, and lead with a final state hadronic system of one or more protons with zero mesons are used to investigate the influence of the nuclear environment on quasielasticlike interactions. The transferred four-momentum squared to the target nucleus, Q^{2}, is reconstructed based on the kinematics of the leading proton, and differential cross sections versus Q^{2} and the cross-section ratios of iron, lead, and carbon to scintillator are measured for the first time in a single experiment. The measurements show a dependence on the atomic number. While the quasielasticlike scattering on carbon is compatible with predictions, the trends exhibited by scattering on iron and lead favor a prediction with intranuclear rescattering of hadrons accounted for by a conventional particle cascade treatment. These measurements help discriminate between different models of both initial state nucleons and final state interactions used in the neutrino oscillation experiments.

  8. Precision measurements of nuclear CR energy spectra and composition with the AMS-02 experiment

    NASA Astrophysics Data System (ADS)

    Fiandrini, E.

    2016-05-01

    The Alpha Magnetic Spectrometer 02 (AMS-02) is a large acceptance high-energy physics experiment operating since May 2011 on board the International Space Station. More than 60 billion events have been collected by the instrument in the first four years of operation. AMS-02 offers a unique opportunity to study the Cosmic Rays (CRs) since it measures the spectra of all the species simultaneously. We report on the precision measurements of primary and secondary nuclear spectra, in the GeV-TeV energy interval. These measurements allow for the first time a detailed study of the spectral index variation with rigidity providing a new insight on the origin and propagation of CR.

  9. Nuclear magnetic resonance measurement of ammonia diffusion in dense solid-liquid slurries

    SciTech Connect

    Bobroff, S.; Phillips, R.J.; Shekarriz, A.

    1997-09-01

    The diffusion of ammonium ions in aqueous solutions was measured by nuclear magnetic resonance (NMR) using the pulsed field gradient (PFG) method. The ammonium ions were obtained from aqueous solutions of ammonium chloride, ammonium sulfate, ammonium bicarbonate, and ammonium hydroxide. The translation diffusion of the ammonium ions was determined by measuring the diffusion of nitrogen nuclei ({sup 14}N and {sup 15}N) in solution. Our results showed that the ammonium diffusion coefficient can be measured in aqueous solutions with concentrations as low as 20 x 10{sup -3} M. Typical values measured for the diffusion coefficient of the ammonium ion are 2 x 10{sup -5} cm{sup 2/s} ({+-}10%), similar to the values found for pure water. Due to the effect of the solution pH upon the NMR relaxation parameters for {sup 14}N, measurements are constrained to pH values below 8.5. However, {sup 15}N labeled ammonium is less sensitive to the solution pH, extending the measurement range to pH of 9.5. Diffusion measurements were conducted with solutions of varying viscosity and porosity. The results show that the solution viscosity has a measureable impact on the diffusion coefficient. The diffusion coefficient is almost inversely proportional to the relative viscosity of the solution, irrespective of how the viscosity is increased. Further, a randomly-packed porous bed of 200 mm PMMA resulted in a reduction of {approximately}30% in the diffusion coefficient as a result of hindered diffusion.

  10. 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.

  11. Large g-factor enhancement in high-mobility InAs/AlSb quantum wells

    NASA Astrophysics Data System (ADS)

    Sadofyev, Yu. G.; Ramamoorthy, A.; Naser, B.; Bird, J. P.; Johnson, S. R.; Zhang, Y.-H.

    2002-09-01

    We discuss the growth by molecular-beam epitaxy, and studies of the low-temperature electrical properties, of undoped InAs/AlSb quantum wells. The two-dimensional electron gas realized in the wells exhibits high mobility at low temperatures, and an analysis of its Shubnikov-de Haas oscillations suggests this mobility is limited by scattering from remotely located unintentional dopants. Spin splitting of the oscillations is clearly resolved at 4.2 K, revealing a g-factor as large as -60 at high magnetic fields. The size of this enhancement increases with decreasing electron density, and is thought to reflect the associated increase in the strength of the effective Coulomb interaction.

  12. Relativistic and QED corrections to the g factor of Li-like ions

    NASA Astrophysics Data System (ADS)

    Glazov, D. A.; Shabaev, V. M.; Tupitsyn, I. I.; Volotka, A. V.; Yerokhin, V. A.; Plunien, G.; Soff, G.

    2004-12-01

    Calculations of various corrections to the g factor of Li-like ions are presented, which result in a significant improvement of the theoretical accuracy in the region Z=6-92 . The configuration-interaction Dirac-Fock method is employed for the evaluation of the interelectronic-interaction correction of order 1/Z2 and higher. This correction is combined with the 1/Z interelectronic-interaction term derived within a rigorous QED approach. The one-electron QED correction of first order in α is obtained by employing our recent results for the self-energy term and by evaluating the vacuum-polarization contribution. The screening of QED corrections is taken into account to the leading orders in αZ and 1/Z .

  13. Measurement of Nuclear Recoils in the CDMS II Dark Matter Search

    NASA Astrophysics Data System (ADS)

    Fallows, Scott M.

    The Cryogenic Dark Matter Search (CDMS) experiment is designed to directly detect elastic scatters of weakly-interacting massive dark matter particles (WIMPs), on target nuclei in semiconductor crystals composed of Si and Ge. These scatters would occur very rarely, in an overwhelming background composed primarily of electron recoils from photons and electrons, as well as a smaller but non-negligible background of WIMP-like nuclear recoils from neutrons. The CDMS~II generation of detectors simultaneously measure ionization and athermal phonon signals from each scatter, allowing discrimination against virtually all electron recoils in the detector bulk. Pulse-shape timing analysis allows discrimination against nearly all remaining electron recoils taking place near detector surfaces. Along with carefully limited neutron backgrounds, this experimental program allowed for "background-free'' operation of CDMS~II at Soudan, with less than one background event expected in each WIMP-search analysis. As a result, exclusionary upper-limits on WIMP-nucleon interaction cross section were placed over a wide range of candidate WIMP masses, ruling out large new regions of parameter space. These results, like any others, are subject to a variety of systematic effects that may alter their final interpretations. A primary focus of this dissertation will be difficulties in precisely calibrating the energy scale for nuclear recoil events like those from WIMPs. Nuclear recoils have suppressed ionization signals relative to electron recoils of the same recoil energy, so the response of the detectors is calibrated differently for each recoil type. The overall normalization and linearity of the energy scale for electron recoils in CDMS~II detectors is clearly established by peaks of known gamma energy in the ionization spectrum of calibration data from a 133Ba source. This electron-equivalent keVee) energy scale enables calibration of the total phonon signal (keVt) by enforcing unity

  14. Integrated Geophysical Measurements for Bioremediation Monitoring: Combining Spectral Induced Polarization, Nuclear Magnetic Resonance and Magnetic Methods

    SciTech Connect

    Keating, Kristina; Slater, Lee; Ntarlagiannis, Dimitris; Williams, Kenneth H.

    2015-02-24

    This documents contains the final report for the project "Integrated Geophysical Measurements for Bioremediation Monitoring: Combining Spectral Induced Polarization, Nuclear Magnetic Resonance and Magnetic Methods" (DE-SC0007049) Executive Summary: Our research aimed to develop borehole measurement techniques capable of monitoring subsurface processes, such as changes in pore geometry and iron/sulfur geochemistry, associated with remediation of heavy metals and radionuclides. Previous work has demonstrated that geophysical method spectral induced polarization (SIP) can be used to assess subsurface contaminant remediation; however, SIP signals can be generated from multiple sources limiting their interpretation value. Integrating multiple geophysical methods, such as nuclear magnetic resonance (NMR) and magnetic susceptibility (MS), with SIP, could reduce the ambiguity of interpretation that might result from a single method. Our research efforts entails combining measurements from these methods, each sensitive to different mineral forms and/or mineral-fluid interfaces, providing better constraints on changes in subsurface biogeochemical processes and pore geometries significantly improving our understanding of processes impacting contaminant remediation. The Rifle Integrated Field Research Challenge (IFRC) site was used as a test location for our measurements. The Rifle IFRC site is located at a former uranium ore-processing facility in Rifle, Colorado. Leachate from spent mill tailings has resulted in residual uranium contamination of both groundwater and sediments within the local aquifer. Studies at the site include an ongoing acetate amendment strategy, native microbial populations are stimulated by introduction of carbon intended to alter redox conditions and immobilize uranium. To test the geophysical methods in the field, NMR and MS logging measurements were collected before, during, and after acetate amendment. Next, laboratory NMR, MS, and SIP measurements

  15. Evidence that the beta-catenin nuclear translocation assay allows for measuring presenilin 1 dysfunction.

    PubMed Central

    Van Gassen, G.; De Jonghe, C.; Nishimura, M.; Yu, G.; Kuhn, S.; St George-Hyslop, P.; Van Broeckhoven, C.

    2000-01-01

    BACKGROUND: Mutations in the presenilin (PSEN) genes are responsible for the majority of early-onset Alzheimer disease (AD) cases. PSEN1 is a component of a high molecular weight, endoplasmic reticulum, membrane-bound protein complex, including beta-catenin. Pathogenic PSEN1 mutations were demonstrated to have an effect on beta-catenin and glycogen synthase kinase-3beta(GSK-3beta), two members of the wingless Wnt pathway. The nuclear translocation and the stability of beta-catenin, and the interaction between GSK3beta and PSEN1 were influenced. MATERIALS AND METHODS: Stably transfected human embryonic kidney (HEK) 293 cells overexpressing wild-type (wt) and mutant (mt) PSEN1, treated with and without LiCl, were used to isolate cytoplasmic and nuclear fractions. By Western blot analysis, endogenous beta-catenin levels were examined. By analyzing cytosolic fractions of PSEN1, transfected and nontransfected HEK 293 cells, and total brain extracts of AD patients and controls, we evaluated the effect of PSEN1 overexpression on beta-catenin stability. Finally, we analyzed the effect of pathogenic PSEN1 mutations on the interaction between PSEN1 and GSK3beta by co-immunoprecipitation experiments. RESULTS: We report reduced nuclear translocation of beta-catenin in cells stably expressing I143T, G384A, and T113-114ins PSEN1. The G384A PSEN1 mutation showed a similar pronounced effect on nuclear translocation of beta-catenin, as reported for processing of amyloid precursor protein (APP) into amyloid beta(Abeta). Overexpression of PSEN1 and the presence of pathogenic mutations in PSEN1 had no significant effect on the stability of beta-catenin. Nonspecific binding of overexpressed PSEN1 to endogenous GSK3beta was observed when GSK3beta was immunoprecipitated. Immunoprecipitation of PSEN1 in cells overexpressing PSEN1 and in native cells, however, did not result in co-immunoprecipitation of endogenous GSK3beta. CONCLUSION: Our results further establish the nuclear

  16. 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.

  17. Ground-state nuclear-moment measurement of neutron-rich sulfur isotopes

    NASA Astrophysics Data System (ADS)

    Ohtomo, Yuichi; Ichikawa, Yuichi; Shirai, Hazuki; Ueno, Hideki; Ishibashi, Youko; Suzuki, Takahiro; Furukawa, Takeshi; Yoshimi, Akihiro; Abe, Yasushi; Asahi, Koichiro; Daugasu, J. M.; Fujita, Tomomi; Hayasaka, Miki; Imamura, Kei; Kishi, Shota; Kojima, Shuichiro; Nagae, Daisuke; Nakao, Aiko; Sagayama, Tsubasa; Sakamoto, Yu; Sato, Tomoya

    2014-09-01

    Recently the erosion of N = 28 shell gap has been suggested from several spectroscopic experimental data on neutron-rich nuclei. In particular, 43S isotope is of much interest since shape coexistence is expected to occur which provides key information to understand the evolution of shell gaps far from the stability. The isomeric state of 43S at 320 keV is suggested to have a shape close to sphericity with spin-parity of 7/2, but both the spin-parity and deformed parameter of the ground-state have not been determined directly. In order to investigate mechanisms leading to such an anomalous nuclear structure, we aim at measuring the ground-state nuclear-moment for 41,43S. As the first step, the measurement of μ moment of 41S was performed using the technique of β-NMR method at the RIPS facility at RIKEN. In the presentation, the result of this work will be reported.

  18. The AMS Measurements and Its Applications in Nuclear Physics at China Institute of Atomic Energy (CIAE)

    SciTech Connect

    Jiang Shan; Shen Hongtao; He Ming; Dong Kejun; He Guozhu; Wang Xianggao; Yuan Jian; Wang Wei; Wu Shaoyong; Ruan Xiangdong; Wu Weimin

    2010-05-12

    Accelerator Mass Spectrometry (AMS), initiated in late 1970s at McMaster university based on the accelerator and detector technique, has long been applied in the studies on archaeology, geology, and cosmology, as a powerful tool for isotope dating. The advantages of AMS in the analysis of rare nuclides by direct counting of the atoms, small sample size and relatively free from the interferences of molecular ions have been well documented. This paper emphasizes that AMS can not only be used for archaeology, geology, environment, biology and so on, but also served as a unique tool for nuclear physics research. In this paper, the determination of the half-lives of {sup 79}Se, the measurements of the cross-sections of {sup 93}Nb(n,2n){sup 92g}Nb and {sup 238}U(n,3n){sup 236}U reactions, the detection and determination of ultratrace impurities in neutrino detector materials, and the measurement of the fission product nuclide {sup 126}Sn, are to be introduced, as some of examples of AMS applications in nuclear research conducted in AMS lab of China Institute of Atomic Energy. Searching for superheavy nuclides by using AMS is being planned.

  19. The AMS Measurements and Its Applications in Nuclear Physics at China Institute of Atomic Energy (CIAE)

    NASA Astrophysics Data System (ADS)

    Jiang, Shan; Shen, Hongtao; He, Ming; Ruan, Xiangdong; Wu, Weimin; Dong, Kejun; He, Guozhu; Wang, Xianggao; Yuan, Jian; Wang, Wei; Wu, Shaoyong

    2010-05-01

    Accelerator Mass Spectrometry (AMS), initiated in late 1970s at McMaster university based on the accelerator and detector technique, has long been applied in the studies on archaeology, geology, and cosmology, as a powerful tool for isotope dating. The advantages of AMS in the analysis of rare nuclides by direct counting of the atoms, small sample size and relatively free from the interferences of molecular ions have been well documented. This paper emphasizes that AMS can not only be used for archaeology, geology, environment, biology and so on, but also served as a unique tool for nuclear physics research. In this paper, the determination of the half-lives of 79Se, the measurements of the cross-sections of 93Nb(n,2n)92gNb and 238U(n,3n)236U reactions, the detection and determination of ultratrace impurities in neutrino detector materials, and the measurement of the fission product nuclide 126Sn, are to be introduced, as some of examples of AMS applications in nuclear research conducted in AMS lab of China Institute of Atomic Energy. Searching for superheavy nuclides by using AMS is being planned.

  20. Karyotype characterization and nuclear DNA content measurement in Bromeliaceae: state of the art and future perspectives.

    PubMed

    Nunes, Andrei C P; Clarindo, Wellington R

    2014-12-01

    In Bromeliaceae, cytogenetic and flow cytometry analyses have been performed to clarify systematic and evolutionary aspects. Karyotyping approaches have shown the relatively high chromosome number, similar morphology and small size of the chromosomes. These facts have prevented a correct chromosome counting and characterization. Authors have established a basic chromosome number of x = 25 for Bromeliaceae. Recently, one karyomorphological analysis revealed that x = 25 is no longer the basic chromosome number, whose genome may have a polyploid origin. Besides cytogenetic characterization, the 2C DNA content of bromeliads has been measured. Nuclear DNA content has varied from 2C = 0.60 to 2C = 3.34 picograms. Thus, in relation to most angiosperms, the 2C DNA content of Bromeliaceae species as well as their chromosome size can be considered relatively small. In spite of some advances, cytogenetic and flow cytometry data are extremely scarce in this group. In this context, this review reports the state of the art in karyotype characterization and nuclear DNA content measurement in Bromeliaceae, emphasizing the main problems and suggesting prospective solutions and ideas for future research.

  1. Rotational and translational water diffusion in the hemoglobin hydration shell: dielectric and proton nuclear relaxation measurements.

    PubMed Central

    Steinhoff, H J; Kramm, B; Hess, G; Owerdieck, C; Redhardt, A

    1993-01-01

    The dynamic properties of water in the hydration shell of hemoglobin have been studied by means of dielectric permittivity measurements and nuclear magnetic resonance spectroscopy. The temperature behavior of the complex permittivity of hemoglobin solutions has been measured at 3.02, 3.98, 8.59, and 10.80 GHz. At a temperature of 298 K the average rotational correlation time tau of water within a hydration shell of 0.5-nm thickness is determined from the activation parameters to be 68 +/- 10 ps, which is 8-fold the corresponding value of bulk water. Solvent proton magnetic relaxation induced by electron-nuclear dipole interaction between hemoglobin bound nitroxide spin labels and water protons is used to determine the translational diffusion coefficient D(T) of the hydration water. The temperature dependent relaxation behavior for Lamor frequencies between 3 and 90 MHz yields an average value D(298K) = (5 +/- 2) x 10(-10)m2 s-1, which is about one-fifth of the corresponding value of bulk water. The decrease of the water mobility in the hydration shell compared to the bulk is mainly due to an enhanced activation enthalpy. PMID:8274642

  2. Nuclear physics experiments with in-beam fast-timing and plunger techniques

    NASA Astrophysics Data System (ADS)

    Sotty, C.

    2017-06-01

    Nuclear lifetime and g factor are crucial observables in nuclear physics, as they give access to the excited states nuclear wave functions using the well-known electromagnetic transition operators. Thus, they are benchmarks to validate or discard nuclear structure theories. During the last decades, the evolution of the nuclear instruments and methods gave birth to several techniques used to measure lifetimes and moments. Among them, the in-beam Fast Electronic Scintillation Timing (FEST) technique is used to measure lifetimes of nuclear states in the picosecond to nanosecond range. Plunger devices originally developed to perform lifetime measurements of excited states in the picosecond range using the Recoil Distance Doppler Shift (RDDS) are now also employed to measure g factor using the new Time-Differential Recoil-In-Vacuum (TDRIV) technique. Recently commissioned, the ROmanian array for SPectroscopy in HEavy ion REactions (ROSPHERE) is dedicated to perform γ-ray spectroscopy, specially suited for lifetime measurements using the RDDS and in-beam fast-timing techniques at the 9 MV Bucharest-Tandem accelerator facility of the Horia Hulubei National Institute of Physics and Nuclear Engineering (IFIN-HH). An introduction of above-mentioned techniques is provided and selected results are illustrating them with physics cases. The in-beam fast-timing and RDDS techniques are described using lifetime measurements respectively in 67Cu and 120Te measured at the 9 MV Bucharest-Tandem accelerator. Finally, the precise g factor measurement of the first-excited state in 24Mg using by the new TDRIV technique at the ALTO-Tandem Orsay facility is presented.

  3. Advanced Nuclear Measurements - Sensitivity Analysis Emerging Safeguards, Problems and Proliferation Risk

    SciTech Connect

    Dreicer, J.S.

    1999-07-15

    During the past year this component of the Advanced Nuclear Measurements LDRD-DR has focused on emerging safeguards problems and proliferation risk by investigating problems in two domains. The first is related to the analysis, quantification, and characterization of existing inventories of fissile materials, in particular, the minor actinides (MA) formed in the commercial fuel cycle. Understanding material forms and quantities helps identify and define future measurement problems, instrument requirements, and assists in prioritizing safeguards technology development. The second problem (dissertation research) has focused on the development of a theoretical foundation for sensor array anomaly detection. Remote and unattended monitoring or verification of safeguards activities is becoming a necessity due to domestic and international budgetary constraints. However, the ability to assess the trustworthiness of a sensor array has not been investigated. This research is developing an anomaly detection methodology to assess the sensor array.

  4. Non-Contact Measurement of Thermal Diffusivity in Ion-Implanted Nuclear Materials

    PubMed Central

    Hofmann, F.; Mason, D. R.; Eliason, J. K.; Maznev, A. A.; Nelson, K. A.; Dudarev, S. L.

    2015-01-01

    Knowledge of mechanical and physical property evolution due to irradiation damage is essential for the development of future fission and fusion reactors. Ion-irradiation provides an excellent proxy for studying irradiation damage, allowing high damage doses without sample activation. Limited ion-penetration-depth means that only few-micron-thick damaged layers are produced. Substantial effort has been devoted to probing the mechanical properties of these thin implanted layers. Yet, whilst key to reactor design, their thermal transport properties remain largely unexplored due to a lack of suitable measurement techniques. Here we demonstrate non-contact thermal diffusivity measurements in ion-implanted tungsten for nuclear fusion armour. Alloying with transmutation elements and the interaction of retained gas with implantation-induced defects both lead to dramatic reductions in thermal diffusivity. These changes are well captured by our modelling approaches. Our observations have important implications for the design of future fusion power plants. PMID:26527099

  5. Non-Contact Measurement of Thermal Diffusivity in Ion-Implanted Nuclear Materials

    NASA Astrophysics Data System (ADS)

    Hofmann, F.; Mason, D. R.; Eliason, J. K.; Maznev, A. A.; Nelson, K. A.; Dudarev, S. L.

    2015-11-01

    Knowledge of mechanical and physical property evolution due to irradiation damage is essential for the development of future fission and fusion reactors. Ion-irradiation provides an excellent proxy for studying irradiation damage, allowing high damage doses without sample activation. Limited ion-penetration-depth means that only few-micron-thick damaged layers are produced. Substantial effort has been devoted to probing the mechanical properties of these thin implanted layers. Yet, whilst key to reactor design, their thermal transport properties remain largely unexplored due to a lack of suitable measurement techniques. Here we demonstrate non-contact thermal diffusivity measurements in ion-implanted tungsten for nuclear fusion armour. Alloying with transmutation elements and the interaction of retained gas with implantation-induced defects both lead to dramatic reductions in thermal diffusivity. These changes are well captured by our modelling approaches. Our observations have important implications for the design of future fusion power plants.

  6. Use of First Order Reversal Curve Measurements to Understand Barkhausen Noise Emission in Nuclear Steel

    SciTech Connect

    McCloy, John S.; Ramuhalli, Pradeep; Henager, Charles H.

    2013-02-25

    A prototypical ferritic/martensitic alloy, HT-9, of interest to the nuclear materials community was investigated for microstructure effects on Barkhausen noise emission and first-order reversal curve (FORC) analysis for three different heat-treated samples. It was observed that Barkhausen noise emission and reversible component of magnetization, computed from the FORC data, decreased with increasing measured mechanical hardness. The results are discussed in terms of the use of magnetic signatures for use in nondestructive interrogation of radiation damage and other microstructural changes in ferritic/martensitic alloys. FORC analysis is shown to be particularly useful for detailed characterization of defect density and pinning, which can be correlated to bulk non-destructive evaluation field measurements such as Barkhausen noise emission.

  7. Nuclear Alignment in Projectile Fragmentation as a Tool for Moment Measurements

    SciTech Connect

    Georgiev, G.; Matea, I.; Oliveira Santos, F. de; Lewitowicz, M.; Daugas, J.M.; Belier, G.; Goutte, H.; Meot, V.; Roig, O.; Astabatyan, R.; Lukyanov, S.; Penionzhkevich, Yu.E.; Balabanski, D.L.; Borremans, D.; Himpe, P.; Neyens, G.; Sawicka, M.

    2004-02-27

    The application of the Time Dependent Perturbed Angular Distribution (TDPAD) method to study isomeric states produced and oriented in projectile-fragmentation reactions provides the opportunity to perform nuclear-moment measurements in a wide range of neutron-rich nuclei, unaccessible by other means. An absolute necessity for the application of the TDPAD technique is a spin-aligned ensemble of nuclei. The preliminary results from a recent application of this method on 61mFe and 54mFe at GANIL, Caen, France showed that a significant increase of the amount of the observed alignment, compared to our previous measurement on 67mNi and 69mCu, can be obtained. Some experimental details, concerning the conservation of the reaction obtained alignment, are discussed.

  8. Non-Contact Measurement of Thermal Diffusivity in Ion-Implanted Nuclear Materials

    DOE PAGES

    Hofmann, F.; Mason, D. R.; Eliason, J. K.; ...

    2015-11-03

    Knowledge of mechanical and physical property evolution due to irradiation damage is essential for the development of future fission and fusion reactors. Ion-irradiation provides an excellent proxy for studying irradiation damage, allowing high damage doses without sample activation. Limited ion-penetration-depth means that only few-micron-thick damaged layers are produced. Substantial effort has been devoted to probing the mechanical properties of these thin implanted layers. Yet, whilst key to reactor design, their thermal transport properties remain largely unexplored due to a lack of suitable measurement techniques. Here we demonstrate non-contact thermal diffusivity measurements in ion-implanted tungsten for nuclear fusion armour. Alloying withmore » transmutation elements and the interaction of retained gas with implantation-induced defects both lead to dramatic reductions in thermal diffusivity. These changes are well captured by our modelling approaches. Our observations have important implications for the design of future fusion power plants.« less

  9. A program to measure new energetic particle nuclear interaction cross sections

    NASA Technical Reports Server (NTRS)

    Guzik, T. G.; Albergo, S.; Chen, C. X.; Costa, S.; Crawford, H. J.; Engelage, J.; Ferrando, P.; Flores, I.; Greiner, L.; Jones, F. C.

    1994-01-01

    The Transport Collaboration, consisting of researchers from institutions in France, Germany, Italy, and the USA, has established a program to make new measurements of nuclear interaction cross sections for heavy projectiles (Z greater than or equal to 2) in targets of liquid H2, He and heavier materials. Such cross sections directly affect calculations of galactic and solar cosmic ray transport through matter and are needed for accurate radiation hazard assessment. To date, the collaboration has obtained data using the Lawrence Berkeley Laboratory Bevalac HISS facility with 20 projectiles from He-4 to Ni-58 in the energy range 393-910 MeV/nucleon. Preliminary results from the analysis of these data are presented here and compared to other measurements and to cross section prediction formulae.

  10. The measurement and interpretation of superallowed 0+→ 0+ nuclear β decay

    NASA Astrophysics Data System (ADS)

    Hardy, J. C.; Towner, I. S.

    2014-11-01

    Measurements of the decay strength of superallowed 0+→ 0+ nuclear β transitions shed light on the fundamental properties of weak interactions. Because of their impact, such measurements were first reported 60 years ago in the early 1950s and have continued unabated ever since, always taking advantage of improvements in experimental techniques to achieve ever higher precision. The results helped first to shape the Electroweak Standard Model but more recently have evolved into sensitively testing that model's predictions. Today they provide the most demanding test of vector-current conservation and of the unitarity of the Cabibbo-Kobayashi-Maskawa matrix, as well as the most restrictive limit on the presence of a scalar current. Here, we review the experimental and theoretical methods that have been, and are being, used to characterize superallowed 0+→ 0+ β transitions and to extract fundamentally important parameters from their analysis.

  11. Non-Contact Measurement of Thermal Diffusivity in Ion-Implanted Nuclear Materials

    SciTech Connect

    Hofmann, F.; Mason, D. R.; Eliason, J. K.; Maznev, A. A.; Nelson, K. A.; Dudarev, S. L.

    2015-11-03

    Knowledge of mechanical and physical property evolution due to irradiation damage is essential for the development of future fission and fusion reactors. Ion-irradiation provides an excellent proxy for studying irradiation damage, allowing high damage doses without sample activation. Limited ion-penetration-depth means that only few-micron-thick damaged layers are produced. Substantial effort has been devoted to probing the mechanical properties of these thin implanted layers. Yet, whilst key to reactor design, their thermal transport properties remain largely unexplored due to a lack of suitable measurement techniques. Here we demonstrate non-contact thermal diffusivity measurements in ion-implanted tungsten for nuclear fusion armour. Alloying with transmutation elements and the interaction of retained gas with implantation-induced defects both lead to dramatic reductions in thermal diffusivity. These changes are well captured by our modelling approaches. Our observations have important implications for the design of future fusion power plants.

  12. Non-Contact Measurement of Thermal Diffusivity in Ion-Implanted Nuclear Materials.

    PubMed

    Hofmann, F; Mason, D R; Eliason, J K; Maznev, A A; Nelson, K A; Dudarev, S L

    2015-11-03

    Knowledge of mechanical and physical property evolution due to irradiation damage is essential for the development of future fission and fusion reactors. Ion-irradiation provides an excellent proxy for studying irradiation damage, allowing high damage doses without sample activation. Limited ion-penetration-depth means that only few-micron-thick damaged layers are produced. Substantial effort has been devoted to probing the mechanical properties of these thin implanted layers. Yet, whilst key to reactor design, their thermal transport properties remain largely unexplored due to a lack of suitable measurement techniques. Here we demonstrate non-contact thermal diffusivity measurements in ion-implanted tungsten for nuclear fusion armour. Alloying with transmutation elements and the interaction of retained gas with implantation-induced defects both lead to dramatic reductions in thermal diffusivity. These changes are well captured by our modelling approaches. Our observations have important implications for the design of future fusion power plants.

  13. Neutron Radiography and Fission Mapping Measurements of Nuclear Materials with Varying Composition and Shielding

    SciTech Connect

    Mullens, James Allen; McConchie, Seth M; Hausladen, Paul; Mihalczo, John T; Grogan, Brandon R; Sword, Eric D

    2011-01-01

    Neutron radiography and fission mapping measurements were performed on four measurement objects with varying composition and shielding arrangements at the Idaho National Laboratory's Zero Power Physics Reactor (ZPPR) facility. The measurement objects were assembled with ZPPR reactor plate materials comprising plutonium, natural uranium, or highly enriched uranium and were presented as unknowns for characterization. As a part of the characterization, neutron radiography was performed using a deuterium-tritium (D-T) neutron generator as a source of time and directionally tagged 14 MeV neutrons. The neutrons were detected by plastic scintillators placed on the opposite side of the object, using the time-correlation-based data acquisition of the Nuclear Materials Identification System developed at Oak Ridge National Laboratory. Each object was measured at several rotations with respect to the neutron source to obtain a tomographic reconstruction of the object and a limited identification of materials via measurement of the neutron attenuation. Large area liquid scintillators with pulse shape discrimination were used to detect the induced fission neutrons. A fission site map reconstruction was produced by time correlating the induced fission neutrons with each tagged neutron from the D-T neutron generator. This paper describes the experimental configuration, the ZPPR measurement objects used, and the neutron imaging and fission mapping results.

  14. Measuring Out-of-Time-Order Correlators on a Nuclear Magnetic Resonance Quantum Simulator

    NASA Astrophysics Data System (ADS)

    Li, Jun; Fan, Ruihua; Wang, Hengyan; Ye, Bingtian; Zeng, Bei; Zhai, Hui; Peng, Xinhua; Du, Jiangfeng

    2017-07-01

    The idea of the out-of-time-order correlator (OTOC) has recently emerged in the study of both condensed matter systems and gravitational systems. It not only plays a key role in investigating the holographic duality between a strongly interacting quantum system and a gravitational system, it also diagnoses the chaotic behavior of many-body quantum systems and characterizes information scrambling. Based on OTOCs, three different concepts—quantum chaos, holographic duality, and information scrambling—are found to be intimately related to each other. Despite its theoretical importance, the experimental measurement of the OTOC is quite challenging, and thus far there is no experimental measurement of the OTOC for local operators. Here, we report the measurement of OTOCs of local operators for an Ising spin chain on a nuclear magnetic resonance quantum simulator. We observe that the OTOC behaves differently in the integrable and nonintegrable cases. Based on the recent discovered relationship between OTOCs and the growth of entanglement entropy in the many-body system, we extract the entanglement entropy from the measured OTOCs, which clearly shows that the information entropy oscillates in time for integrable models and scrambles for nonintgrable models. With the measured OTOCs, we also obtain the experimental result of the butterfly velocity, which measures the speed of correlation propagation. Our experiment paves a way for experimentally studying quantum chaos, holographic duality, and information scrambling in many-body quantum systems with quantum simulators.

  15. Measurement of plutonium in spent nuclear fuel by self-induced x-ray fluorescence

    SciTech Connect

    Hoover, Andrew S; Rudy, Cliff R; Tobin, Steve J; Charlton, William S; Stafford, A; Strohmeyer, D; Saavadra, S

    2009-01-01

    Direct measurement of the plutonium content in spent nuclear fuel is a challenging problem in non-destructive assay. The very high gamma-ray flux from fission product isotopes overwhelms the weaker gamma-ray emissions from plutonium and uranium, making passive gamma-ray measurements impossible. However, the intense fission product radiation is effective at exciting plutonium and uranium atoms, resulting in subsequent fluorescence X-ray emission. K-shell X-rays in the 100 keV energy range can escape the fuel and cladding, providing a direct signal from uranium and plutonium that can be measured with a standard germanium detector. The measured plutonium to uranium elemental ratio can be used to compute the plutonium content of the fuel. The technique can potentially provide a passive, non-destructive assay tool for determining plutonium content in spent fuel. In this paper, we discuss recent non-destructive measurements of plutonium X-ray fluorescence (XRF) signatures from pressurized water reactor spent fuel rods. We also discuss how emerging new technologies, like very high energy resolution microcalorimeter detectors, might be applied to XRF measurements.

  16. An investigation of temperature measurement methods in nuclear power plant reactor pressure vessel annealing

    SciTech Connect

    Acton, R.U.; Gill, W.; Sais, D.J.; Schulze, D.H.; Nakos, J.T.

    1996-05-01

    The objective of this project was to provide an assessment of several methods by which the temperature of a commercial nuclear power plant reactor pressure vessel (RPV) could be measured during an annealing process. This project was a coordinated effort between DOE`s Office of Nuclear Energy, Science and Technology; DOE`s Light Water Reactor Technology Center at Sandia National Laboratories; and the Electric Power Research Institute`s Non- Destructive Evaluation Center. Ball- thermocouple probes similar to those described in NUREG/CR-5760, spring-loaded, metal- sheathed thermocouple probes, and 1778 air- suspended thermocouples were investigated in experiments that heated a section of an RPV wall to simulate a thermal annealing treatment. A parametric study of ball material, emissivity, thermal conductivity, and thermocouple function locations was conducted. Also investigated was a sheathed thermocouple failure mode known as shunting (electrical breakdown of insulation separating the thermocouple wires). Large errors were found between the temperature as measured by the probes and the true RPV wall temperature during heat-up and cool-down. At the annealing soak temperature, in this case 454{degrees}C [850`F], all sensors measured the same temperature within about {plus_minus}5% (23.6{degrees}C [42.5{degrees}F]). Because of these errors, actual RPV wall heating and cooling rates differed from those prescribed (by up to 29%). Shunting does not appear to be a problem under these conditions. The large temperature measurement errors led to the development of a thermal model that predicts the RPV wall temperature from the temperature of a ball- probe. Comparisons between the model and the experimental data for ball-probes indicate that the model could be a useful tool in predicting the actual RPV temperature based on the indicated ball- probe temperature. The model does not predict the temperature as well for the spring-loaded and air suspended probes.

  17. Nuclear relaxation measurements in organic semiconducting polymers for application to organic spintronics

    NASA Astrophysics Data System (ADS)

    Thenell, E. F.; Limes, M. E.; Sorte, E. G.; Vardeny, Z. V.; Saam, B.

    2015-01-01

    NMR measurements of spin-lattice relaxation of hydrogen nuclei in two prototype organic semiconducting solids, MEH-PPV and DOO-PPV, were carried out for temperatures between 4.2 K and room temperature, and for applied magnetic fields between 1.25 and 4.7 T. These π -conjugated polymers are of interest for use as the active semiconducting layer in spintronic devices. They typically exhibit weak spin-orbit coupling, and the interaction with inhomogeneous hyperfine fields generated by the nuclear spins plays a significant, if not dominant, role in the spin coherence and spin relaxation of electronic charge carriers. Our studies were conducted on unbiased bulk material with no photo-illumination. The characteristic 1H longitudinal relaxation times in these materials ranges from hundreds of milliseconds to >1000 s, and are predominantly nonmonoexponential. We present the data both in terms of a recovery time, T1 /2, corresponding to 50% recovery of thermal magnetization from saturation and in terms of a "T1 spectrum" produced via a numerical Laplace transform of the time-domain data. The evidence best supports relaxation to paramagnetic centers (radicals) mediated by nuclear spin diffusion as the primary mechanism: the observed relaxation is predominantly nonmonoexponential, and a characteristic T1 minimum as a function of temperature is apparent for both materials somewhere between 77 K and room temperature. The paramagnetic centers may be somewhat-delocalized charge-carrier pairs (i.e., polarons) along the polymer backbone, although the concentration in an unbiased sample (no carrier injection) should be very low. Alternatively, the centers may be localized defects, vacancies, or impurities. Our results may also be used to judge the feasibility of Overhauser-type dynamic nuclear polarization from polarized charge carriers or optically pumped exciton states.

  18. Ambient Dose Equivalent measured at the Instituto Nacional de Cancerologia Department of Nuclear Medicine

    SciTech Connect

    Avila, O.; Torres-Ulloa, C. L.; Medina, L. A.; Trujillo-Zamudio, F. E.; Gamboa de Buen, I.; Buenfil, A. E.; Brandan, M. E.

    2010-12-07

    Ambient dose equivalent values were determined in several sites at the Instituto Nacional de Cancerologia, Departmento de Medicina Nuclear, using TLD-100 and TLD-900 thermoluminescent dosemeters. Additionally, ambient dose equivalent was measured at a corridor outside the hospitalization room for patients treated with {sup 137}Cs brachytherapy. Dosemeter calibration was performed at the Instituto Nacional de Investigaciones Nucleares, Laboratorio de Metrologia, to known {sup 137}Cs gamma radiation air kerma. Radionuclides considered for this study are {sup 131}I, {sup 18}F, {sup 67}Ga, {sup 99m}Tc, {sup 111}In, {sup 201}Tl and {sup 137}Cs, with main gamma energies between 93 and 662 keV. Dosemeters were placed during a five month period in the nuclear medicine rooms (containing gamma-cameras), injection corridor, patient waiting areas, PET/CT study room, hot lab, waste storage room and corridors next to the hospitalization rooms for patients treated with {sup 131}I and {sup 137}Cs. High dose values were found at the waste storage room, outside corridor of {sup 137}Cs brachytherapy patients and PET/CT area. Ambient dose equivalent rate obtained for the {sup 137}Cs brachytherapy corridor is equal to (18.51{+-}0.02)x10{sup -3} mSv/h. Sites with minimum doses are the gamma camera rooms, having ambient dose equivalent rates equal to (0.05{+-}0.03)x10{sup -3} mSv/h. Recommendations have been given to the Department authorities so that further actions are taken to reduce doses at high dose sites in order to comply with the ALARA principle (as low as reasonably achievable).

  19. Nuclear Structure Measurements of Fermium-254 and Advances in Target Production Methodologies

    NASA Astrophysics Data System (ADS)

    Gothe, Oliver Ralf

    The Berkeley Gas-filled Separator (BGS) has been upgraded with a new gas control system. It allows for accurate control of hydrogen and helium gas mixtures. This greatly increases the capabilities of the separator by reducing background signals in the focal plane detector for asymmetric nuclear reactions. It has also been shown that gas mixtures can be used to focus the desired reaction products into a smaller area, thereby increasing the experimental efficiency. A new electrodeposition cell has been developed to produce metal oxide targets for experiments at the BGS. The new cell has been characterized and was used to produce americium targets for the production of element 115 in the reaction 243Am(48Ca.3n) 288115. Additionally, a new method of producing targets for nuclear reactions was explored. A procedure for producing targets via Polymer Assisted Deposition (PAD) was developed and targets produced via this method were tested using the nuclear reaction 208Pb(40Ar.4 n)244Fm to determine their in-beam performance. It was determined that the silicon nitride backings used in this procedure are not feasible due to their crystal structures, and alternative backing materials have been tested and proposed. A previously unknown level in 254Fm has been identified at 985.7 keV utilizing a newly developed low background coincident apparatus. 254m was produced in the reaction 208Pb(48Ca. n)254No. Reaction products were guided to the two-clover low background detector setup via a recoil transfer chamber. The new level has been assigned a spin of 2- and has tentatively been identified as the octupole vibration in 254Fm. Transporting evaporation residues to a two-clover, low background detector setup can effectively be used to perform gamma-spectroscopy measurements of nuclei that are not accessible by current common methodologies. This technique provides an excellent addition to previously available tools such as in-beam spectroscopy and gamma-ray tracking arrays.

  20. The Effect of the Presence and Density of Shewanella oneidensis on Nuclear Magnetic Relaxation Measurements

    NASA Astrophysics Data System (ADS)

    Keating, K.; Halsey, J.

    2011-12-01

    A recent interest in the use of non-invasive geophysical methods to detect the presence of and measure the growth of microbes in the subsurface has arisen due to the potential use of such methods to monitor the progress of bioremediation. Previous research to this end has focused on electrical measurements, such as complex resistivity, which are sensitive to the presence of microbes but can be difficult to interpret. Nuclear magnetic resonance (NMR), an emerging near-surface geophysical method, is sensitive to the presence and physiochemical environment of hydrogen. Typically, NMR measurements in geophysics are used to detect hydrogen in water or hydrocarbons and to determine its pore environment; however, NMR imaging measurements have shown that NMR can also detect hydrogen in microbes. Geophysical NMR measurements thus have the potential to directly detect microbes in geologic material or indirectly detect the way in which the presence of microbes alters the physical and chemical properties of a water-saturated geologic material. This laboratory-scale study was designed to explore the effect of the presence and density of microbes on NMR relaxation measurements. Measurements were collected on microbial slurries and microbes in porous media both during microbial growth and on samples with known microbial density. Shewanella oneidensis was used as a representative environmental microbe in this study. The research shows that low field NMR measurements are sensitive to the presence and density of microbes and provides fundamental information required to determine if low-field NMR measurements can be used to monitor microbial growth during bioremediation.

  1. Parametric study of the energy deposition inside the 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.

    2015-11-01

    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 and two calorimetric cells. Then these measurements are used for other experimental conditions in order to predict the nuclear heating and thermal conditions induced in the irradiation devices. This paper will present simulations with MCNP5 Monte-Carlo transport code (using ENDF/B-VI nuclear data library) to evaluate the nuclear heating inside the calorimeter during irradiation campaigns of the CARMEN-1P mock-up inside OSIRIS reactor periphery (MTR based on Saclay, France). The whole complete geometry of the sensor has been considered. The calculation method corresponds to a calculation in two steps. Consequently, we used as an input source in the model, the neutron and photon spectra calculated in various experimental locations tested during the irradiation campaign (H9, H10, H11, D9). After a description of the differential calorimeter sensor, the MCNP5 model used for the calculations of nuclear heating inside the calorimeter elements is introduced by two quantities: KERMA and energy deposition rate per mass unit. The Charged Particle Equilibrium (CPE) inside the calorimeter elements is studied. The contribution of prompt gamma and neutron is determined. A comparison between this total nuclear heating calculation and the experimental results in a graphite sample will be made. Then parametric studies performed on the influence of the various calorimeter components on the nuclear heating are presented and discussed. The studies of the influence of the nature of materials, the sensor jacket, the source type and the comparison of the results obtained for the two calorimetric cells leads to some proposals for the sensor improvement.

  2. National intercomparisons of 131I radioactivity measurements in nuclear medicine centres in India.

    PubMed

    Joseph, Leena; Anuradha, R; Nathuram, R; Shaha, V V; Abani, M C

    2003-01-01

    National intercomparisons of activity measurements of 131I, a radioisotope widely used for diagnosis and therapy of thyroid related ailments, were initiated in 1979 as a quality assurance program, towards improving radiation safety procedures and related dosimetry in Nuclear Medicine Centres (NMCs) in India. Oral administration of a known quantity of radioiodine to patients requires accurate radioactivity measurements to be performed on a well-calibrated isotope calibrators. Under or over estimation of the activity due to a faulty or uncalibrated isotope calibrator could provide misleading results. Calibration of isotope calibrators and the traceablity of subsequent measurements to the national standards laboratory is one of the essential basic radiation safety requirement of the IAEA. In view of the stringent quality assurance requirements for activity measurements imposed by Atomic Energy Regulatory Board, a National Intercomparison Program was initiated and to date ten such intercomparison programs have been conducted by the Radiation Safety Systems Division, of the Bhabha Atomic Research Centre. This program has benefited the participants by making their measurements traceable to the National Primary Standards. Over the years there has been a marked increase in the number of NMCs participating in the intercomparison programs. As a result, the number of institution showing large deviation from the correct value has decreased considerably over the years. This program thus, has enabled participating NMCs to check their isotope calibrators so as to ensure proper delivery of radiation dose to the patients and hence to optimise patient exposure.

  3. Integration of neural networks with fuzzy reasoning for measuring operational parameters in a nuclear reactor

    SciTech Connect

    Ikonomopoulos, A.; Tsoukalas, L.H. . Dept. of Nuclear Engineering); Uhrig, R.E. )

    1993-10-01

    A novel approach is described for measuring variables with operational significance in a complex system such as a nuclear reactor. The methodology is based on the integration of artificial neural networks with fuzzy reasoning. Neural networks are used to map dynamic time series to a set of user-defined linguistic labels called fuzzy values. The process takes place in a manner analogous to that of measurement. Hence, the entire procedure is referred to as virtual measurement and its software implementation as a virtual measuring device. An optimization algorithm based on information criteria and fuzzy algebra augments the process and assists in the identification of different states of the monitored parameter. The proposed technique is applied for monitoring parameters such as performance, valve position, transient type, and reactivity. The results obtained from the application of the neural network-fuzzy reasoning integration in a high power research reactor clearly demonstrate the excellent tolerance of the virtual measuring device to faulty signals as well as its ability to accommodate noisy inputs.

  4. 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.

  5. Deuteron nuclear data for the design of accelerator-based neutron sources: Measurement, model analysis, evaluation, and application

    NASA Astrophysics Data System (ADS)

    Watanabe, Yukinobu; Kin, Tadahiro; Araki, Shouhei; Nakayama, Shinsuke; Iwamoto, Osamu

    2017-09-01

    A comprehensive research program on deuteron nuclear data motivated by development of accelerator-based neutron sources is being executed. It is composed of measurements of neutron and gamma-ray yields and production cross sections, modelling of deuteron-induced reactions and code development, nuclear data evaluation and benchmark test, and its application to medical radioisotopes production. The goal of this program is to develop a state-of-the-art deuteron nuclear data library up to 200 MeV which will be useful for the design of future (d,xn) neutron sources. The current status and future plan are reviewed.

  6. [Measures against Radiation Exposure Due to Large-Scale Nuclear Accident in Distant Place--Radioactive Materials in Nagasaki from Fukushima Daiichi Nuclear Power Plant].

    PubMed

    Yuan, Jun; Sera, Koichiro; Takatsuji, Toshihiro

    2015-01-01

    To investigate human health effects of radiation exposure due to possible future nuclear accidents in distant places and other various findings of analysis of the radioactive materials contaminating the atmosphere of Nagasaki due to the Fukushima Daiichi Nuclear Power Plant accident. The concentrations of radioactive materials in aerosols in the atmosphere of Nagasaki were measured using a germanium semiconductor detector from March 2011 to March 2013. Internal exposure dose was calculated in accordance with ICRP Publ. 72. Air trajectories were analyzed using NOAA and METEX web-based systems. (134)Cs and (137)Cs were repeatedly detected. The air trajectory analysis showed that (134)Cs and (137)Cs flew directly from the Fukushima Daiichi Nuclear Power Plant from March to April 2011. However, the direct air trajectories were rarely detected after this period even when (134)Cs and (137)Cs were detected after this period. The activity ratios ((134)Cs/(137)Cs) of almost all the samples converted to those in March 2011 were about unity. This strongly suggests that the (134)Cs and (137)Cs detected mainly originated from the Fukushima Daiichi Nuclear Power Plant accident in March 2011. Although the (134)Cs and (137)Cs concentrations per air volume were very low and the human health effects of internal exposure via inhalation is expected to be negligible, the specific activities (concentrations per aerosol mass) were relatively high. It was found that possible future nuclear accidents may cause severe radioactive contaminations, which may require radiation exposure control of farm goods to more than 1000 km from places of nuclear accidents.

  7. Development of neutron measurement in high gamma field using new nuclear emulsion

    SciTech Connect

    Kawarabayashi, J.; Ishihara, K.; Takagi, K.; Tomita, H.; Iguchi, T.; Naka, T.; Morishima, K.; Maeda, S.

    2011-07-01

    To precisely measure the neutron emissions from a spent fuel assembly of a fast breeder reactor, we formed nuclear emulsions based on a non-sensitized Oscillation Project with Emulsion tracking Apparatus (OPERA) film with AgBr grain sizes of 60, 90, and 160 nm. The efficiency for {sup 252}Cf neutron detection of the new emulsion was calculated to be 0.7 x 10{sup -4}, which corresponded to an energy range from 0.3 to 2 MeV and was consistent with a preliminary estimate based on experimental results. The sensitivity of the new emulsion was also experimentally estimated by irradiating with 565 keV and 14 MeV neutrons. The emulsion with an AgBr grain size of 60 nm had the lowest sensitivity among the above three emulsions but was still sensitive enough to detect protons. Furthermore, the experimental data suggested that there was a threshold linear energy transfer of 15 keV/{mu}m for the new emulsion, below which no silver clusters developed. Further development of nuclear emulsion with an AgBr grain size of a few tens of nanometers will be the next stage of the present study. (authors)

  8. Laser-Induced Fluorescence Measurements for Optical Single Atom Detection for Nuclear Astrophysics

    NASA Astrophysics Data System (ADS)

    Parzuchowski, Kristen; Singh, Jaideep; Wenzl, Jennifer; Frisbie, Dustin; Johnson, Maegan

    2016-09-01

    We propose a new highly selective detector to measure rare nuclear reactions relevant for nuclear astrophysics. Our primary interest is the 22Ne(α , n) 25Mg reaction, which is a primary source of neutrons for the s-process. Our proposed detector, in conjunction with a recoil separator, captures the recoil products resulting from the reaction in a cryogenically frozen thin film of solid neon. The fluorescence spectra of the captured atoms is shifted from the absorption spectra by hundreds of nanometers. This allows for the optical detection of individual fluorescence photons against a background of intense excitation light. We will describe our initial studies of laser-induced fluorescence of Yb and Mg in solid Ne. Neon is an attractive medium because it is optically transparent and provides efficient, pure, stable, & chemically inert confinement for a wide variety of atomic and molecular species. Yb is used as a test atom because of its similar atomic structure to Mg and much brighter fluorescence signal. This work is supported by funds from Michigan State University.

  9. Nuclear Magnetic Dipole and Electric Quadrupole Moments: Their Measurement and Tabulation as Accessible Data

    SciTech Connect

    Stone, N. J.

    2015-09-15

    The most recent tabulations of nuclear magnetic dipole and electric quadrupole moments have been prepared and published by the Nuclear Data Section of the IAEA, Vienna [N. J. Stone, Report No. INDC(NDS)-0650 (2013); Report No. INDC(NDS)-0658 (2014)]. The first of these is a table of recommended quadrupole moments for all isotopes in which all experimental results are made consistent with a limited number of adopted standards for each element; the second is a combined listing of all measurements of both moments. Both tables cover all isotopes and energy levels. In this paper, the considerations relevant to the preparation of both tables are described, together with observations as to the importance and (where appropriate) application of necessary corrections to achieve the “best” values. Some discussion of experimental methods is included with emphasis on their precision. The aim of the published quadrupole moment table is to provide a standard reference in which the value given for each moment is the best available and for which full provenance is given. A table of recommended magnetic dipole moments is in preparation, with the same objective in view.

  10. Dissolution Dynamic Nuclear Polarization Instrumentation for Real-time Enzymatic Reaction Rate Measurements by NMR.

    PubMed

    Balzan, Riccardo; Fernandes, Laetitia; Comment, Arnaud; Pidial, Laetitia; Tavitian, Bertrand; Vasos, Paul R

    2016-02-23

    The main limitation of NMR-based investigations is low sensitivity. This prompts for long acquisition times, thus preventing real-time NMR measurements of metabolic transformations. Hyperpolarization via dissolution DNP circumvents part of the sensitivity issues thanks to the large out-of-equilibrium nuclear magnetization stemming from the electron-to-nucleus spin polarization transfer. The high NMR signal obtained can be used to monitor chemical reactions in real time. The downside of hyperpolarized NMR resides in the limited time window available for signal acquisition, which is usually on the order of the nuclear spin longitudinal relaxation time constant, T1, or, in favorable cases, on the order of the relaxation time constant associated with the singlet-state of coupled nuclei, TLLS. Cellular uptake of endogenous molecules and metabolic rates can provide essential information on tumor development and drug response. Numerous previous hyperpolarized NMR studies have demonstrated the relevancy of pyruvate as a metabolic substrate for monitoring enzymatic activity in vivo. This work provides a detailed description of the experimental setup and methods required for the study of enzymatic reactions, in particular the pyruvate-to-lactate conversion rate in presence of lactate dehydrogenase (LDH), by hyperpolarized NMR.

  11. Porosities and permeability of Paleozoic sandstones derived from Nuclear Magnetic Resonance measurements

    NASA Astrophysics Data System (ADS)

    Jorand, Rachel; Koch, Andreas; Mohnke, Oliver; Klitzsch, Norbert; Clauser, Christoph

    2010-05-01

    A major obstacle for an increased use of geothermal energy often lies in the high success risk for the development of geothermal reservoirs due to the unknown rock properties. In general, the ranges of porosity and permeability in existing compilations of rock properties are too large to be useful to constrain properties for specific sites. Usually, conservative assumptions are made about these properties, resulting in greater drilling depth and increased exploration cost. In this study, data from direct measurements on thirty-three sandstones from different borehole locations and depths enable to derive statistical values of the desired hydraulic properties for selected sandstones in the German subsurface. We used Nuclear Magnetic Resonance (NMR) measurements to estimate the porosity and the permeability of sandstones from North Rhine-Westphalia (Germany). Besides NMR standard poro-perm-measurements were performed on the samples to obtain independent data sets for comparison. Porosity was measured by Archimedes principle and pore-size distribution by mercury injection. Also permeability was determined by gas flow measurements taking into account the Klinkenberg effect. The porosities of the studied samples vary between 0 % and 16 %. NMR yields suitable porosity results whereas the porosities obtain by T1 relaxation measurements fit better to the Archimedes porosities than the porosities obtained by T2 relaxation measurements. For porosities up to 10 %, T2 relaxation measurements overestimate the porosity. Furthermore, we calculate the effective porosity using a cutoff time of 3 ms. This effective porosity agrees much better with Archimedes porosities, particularly for the low porosity samples. The gas permeability of studied sandstones varies between 10-21 m2 and 2.10-17 m2. A large number of empirical relationships between relaxation times and gas permeability have been published. We have applied several of these relationships to select the appropriate law for

  12. The Effect of Measurement Bias on Nuclear Criticality Safety Calculations for WIPP TRUPACT-II Shipments

    SciTech Connect

    Blackwood, Larry G.; Harker, Yale D.

    2000-12-15

    Current nuclear criticality safety limit requirements for transporting TRUPACT-II waste containers to the U.S. Department of Energy's Waste Isolation Pilot Plant (WIPP) specify that the {sup 239}Pu fissile gram equivalent (FGE) plus two times its measurement error must be {<=}325 g for a payload of fourteen 55-gal drums. The authorized method for calculating a TRUPACT-II FGE measurement error value is to take the square root of the sum of the squared error values for the individual containers (often called root-sum-squares or simply RSS). However, to the extent that the individual drum measurements contain common bias effects (e.g., due to common calibration or other adjustment factors), the corresponding measurement errors are correlated, and simple RSS calculations will underestimate the true error in the TRUPACT-II FGE value.The RSS calculations assume independence, while common bias effects can induce strong correlations between the errors in measurements. Significant bias effects can occur when the matrix characteristics for a particular waste type are not fully accounted for in the measurement process. Depending on the relative size of the bias error compared to precision error, the true measurement error can be greater than twice that calculated by RSS. In such cases, the FGE shipping requirement may not be met. To avoid underestimating the error, bias components should be estimated and propagated separately (combined only at the final step in the TRUPACT-II FGE calculation), or the effect of bias on covariance between measurements must be calculated. These covariance terms then need to be included in the final uncertainty calculations.

  13. The ULT trxG factors play a role in arabidopsis fertilization

    PubMed Central

    Monfared, Mona M; Fletcher, Jennifer C

    2014-01-01

    Trithorax group (trxG) and Polycomb group (PcG) proteins are epigenetic modifiers that play key roles in eukaryotic development by promoting active or repressive gene expression states, respectively. Although PcG proteins have well-defined roles in controlling developmental transitions, cell fate decisions and cellular differentiation in plants, relatively little is known about the functions of plant trxG factors. We recently determined the biological roles for the ULT1 and ULT2 trxG genes during Arabidopsis vegetative and reproductive development. Our study revealed that ULT1 and ULT2 genes have overlapping activities in regulating Arabidopsis shoot and floral stem cell activity, and that they have a redundant function in establishing the apical-basal polarity axis of the gynoecium. Here we present data that ult1 and ult1 ult2 siliques contain a significant proportion of aborted ovules, supporting an additional role for ULT1 in Arabidopsis fertility. Our results add to the number of plant developmental processes that are regulated by trxG activity. PMID:25531183

  14. 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''.

  15. Characterization of high-level nuclear waste glass using magnetic measurements

    SciTech Connect

    Senftle, F.E.; Thorpe, A.N.; Grant, J.R.; Barkatt, A.

    1994-12-31

    Magnetic measurements constitute a promising method for the characterization of nuclear waste glasses in view of their simplicity and small sample weight requirements. Initial studies of simulated high-level waste glasses show that the Curie constant is generally a useful indicator of the Fe{sup 2+}:Fe{sup 3+} ratio. Glasses produced by air-cooling in large vessels show systematic deviations between experimental and calcined values, which are indicative of the presence of small amounts of crystalline iron-containing phases. Most of the iron in these phases becomes dissolved in the glass upon re-heating and more rapid quenching. The studies further show that upon leaching the glass in water some of the iron in the surface regions of the glass is converted to a form which has high temperature-independent magnetic susceptibility.

  16. Application of TL dosemeters for dose distribution measurements at high temperatures in nuclear reactors.

    PubMed

    Osvay, M; Deme, S

    2006-01-01

    Al2O3:Mg,Y ceramic thermoluminescence dosemeters were developed at the Institute of Isotopes for high dose applications at room temperatures. The glow curve of Al2O3:Mg,Y exhibits two peaks--one at 250 degrees C (I) and another peak at approximately 400 degrees C (II). In order to extend the application of these dosemeters to high temperatures, the effect of irradiation temperature was investigated using temperature controlled heating system during high dose irradiation at various temperatures (20-100 degrees C). The new calibration and measuring method has been successfully applied for dose mapping within the hermetic zone of the Paks Nuclear Power Plant even at high temperature parts of blocks.

  17. Nuclear magnetic resonance measurements of velocity distributions in an ultrasonically vibrated granular bed

    PubMed Central

    Huntley, J. M.; Tarvaz, T.; Mantle, M. D.; Sederman, A. J.; Gladden, L. F.; Sheikh, N. A.; Wildman, R. D.

    2014-01-01

    We report the results of nuclear magnetic resonance imaging experiments on granular beds of mustard grains fluidized by vertical vibration at ultrasonic frequencies. The variation of both granular temperature and packing fraction with height was measured within the three-dimensional cell for a range of vibration frequencies, amplitudes and numbers of grains. Small increases in vibration frequency were found—contrary to the predictions of classical ‘hard-sphere’ expressions for the energy flux through a vibrating boundary—to result in dramatic reductions in granular temperature. Numerical simulations of the grain–wall interactions, using experimentally determined Hertzian contact stiffness coefficients, showed that energy flux drops significantly as the vibration period approaches the grain–wall contact time. The experiments thus demonstrate the need for new models for ‘soft-sphere’ boundary conditions at ultrasonic frequencies. PMID:24711488

  18. Nuclear magnetic resonance measurements of velocity distributions in an ultrasonically vibrated granular bed.

    PubMed

    Huntley, J M; Tarvaz, T; Mantle, M D; Sederman, A J; Gladden, L F; Sheikh, N A; Wildman, R D

    2014-05-13

    We report the results of nuclear magnetic resonance imaging experiments on granular beds of mustard grains fluidized by vertical vibration at ultrasonic frequencies. The variation of both granular temperature and packing fraction with height was measured within the three-dimensional cell for a range of vibration frequencies, amplitudes and numbers of grains. Small increases in vibration frequency were found--contrary to the predictions of classical 'hard-sphere' expressions for the energy flux through a vibrating boundary--to result in dramatic reductions in granular temperature. Numerical simulations of the grain-wall interactions, using experimentally determined Hertzian contact stiffness coefficients, showed that energy flux drops significantly as the vibration period approaches the grain-wall contact time. The experiments thus demonstrate the need for new models for 'soft-sphere' boundary conditions at ultrasonic frequencies.

  19. Time of flight measurements of unirradiated and irradiated nuclear graphite under cyclic compressive load

    NASA Astrophysics Data System (ADS)

    Bodel, W.; Atkin, C.; Marsden, B. J.

    2017-04-01

    The time-of-flight technique has been used to investigate the stiffness of nuclear graphite with respect to the grade and grain direction. A loading rig was developed to collect time-of-flight measurements during cycled compressive loading up to 80% of the material's compressive strength and subsequent unloading of specimens along the axis of the applied stress. The transmission velocity (related to Young's modulus), decreased with increasing applied stress; and depending on the graphite grade and orientation, the modulus then increased, decreased or remained constant upon unloading. These tests were repeated while observing the microstructure during the load/unload cycles. Initial decreases in transmission velocity with compressive load are attributed to microcrack formation within filler and binder phases. Three distinct types of behaviour occur on unloading, depending on the grade, irradiation, and loading direction. These different behaviours can be explained in terms of the material microstructure observed from the microscopy performed during loading.

  20. Nuclear reaction measurements on tissue-equivalent materials and GEANT4 Monte Carlo simulations for hadrontherapy

    NASA Astrophysics Data System (ADS)

    De Napoli, M.; Romano, F.; D'Urso, D.; Licciardello, T.; Agodi, C.; Candiano, G.; Cappuzzello, F.; Cirrone, G. A. P.; Cuttone, G.; Musumarra, A.; Pandola, L.; Scuderi, V.

    2014-12-01

    When a carbon beam interacts with human tissues, many secondary fragments are produced into the tumor region and the surrounding healthy tissues. Therefore, in hadrontherapy precise dose calculations require Monte Carlo tools equipped with complex nuclear reaction models. To get realistic predictions, however, simulation codes must be validated against experimental results; the wider the dataset is, the more the models are finely tuned. Since no fragmentation data for tissue-equivalent materials at Fermi energies are available in literature, we measured secondary fragments produced by the interaction of a 55.6 MeV u-1 12C beam with thick muscle and cortical bone targets. Three reaction models used by the Geant4 Monte Carlo code, the Binary Light Ions Cascade, the Quantum Molecular Dynamic and the Liege Intranuclear Cascade, have been benchmarked against the collected data. In this work we present the experimental results and we discuss the predictive power of the above mentioned models.

  1. Nuclear reaction measurements of 95 MeV/u 12C interactions on PMMA for hadrontherapy

    NASA Astrophysics Data System (ADS)

    Braunn, B.; Labalme, M.; Ban, G.; Chevallier, M.; Colin, J.; Cussol, D.; Dauvergne, D.; Fontbonne, J. M.; Haas, F.; Guertin, A.; Lebhertz, D.; Le Foulher, F.; Pautard, C.; Ray, C.; Rousseau, M.; Salsac, M. D.; Stuttge, L.; Testa, E.; Testa, M.

    2011-11-01

    The ion dose deposition in tissues is characterized by a favorable depth dose profile (i.e. Bragg peak) and a small lateral spread. In order to keep these benefits of ions in cancer treatments, a very high accuracy is required on the dose deposition (±3%). For given target stoichiometry and geometry, the largest uncertainty on the physical dose deposition is due to the ion nuclear fragmentation. We have performed an experiment at GANIL with a 95 MeV/u 12C beam on thick tissue equivalent PMMA targets (thicknesses: 5, 10, 15, 20 and 25 mm). The main goals of this experiment are to provide experimental fragmentation data for benchmarking the physical models used for treatment planning. Production rates, energy and angular distributions of charged fragments have been measured. The purpose of this paper is to present the results of this experiment.

  2. Measuring the Fr Weak Nuclear Charge by Observing a Linear Stark Shift with Small Atomic Samples

    SciTech Connect

    Bouchiat, Marie-Anne

    2008-03-28

    We study the chirality of ground-state alkali atoms in E and B fields, dressed with a circularly-polarized beam near-detuned (< or approx. )1 GHz) from an E-field-assisted forbidden transition such as 7S-8S in Fr. We predict parity violating energy shifts of their sublevels, linear in E and the weak nuclear charge Q{sub W}. A dressing beam of 10 kW/cm{sup 2} at 506 nm produces a shift of {approx}100 {mu}Hz at E=100 V/cm, B > or approx. 50 mG which should be observable with {approx}10{sup 4} Fr atoms confined in an optical dipole trap. We discuss optimal conditions, parameter reversals, and a calibration procedure to measure Q{sub W}.

  3. Measurements of alpha particle energy using nuclear tracks in solids methodology.

    PubMed

    Espinosa, G; Amero, C; Gammage, R B

    2002-01-01

    In this paper we present a method for the measurement of alpha particle energy using polycarbonate materials as nuclear track detectors (NTDs). This method is based on the interaction of the radiation with the solid-state materials, using the relationship between the energy deposited in the material by the ionising particle and the track developed after an established chemical process. The determination of the geometrical parameters of the formed track, such as major axis, minor axis and overall track length, permit determination of the energy of the alpha particle. The track analysis is performed automatically using a digital image system, and the data are processed in a PC with commercial software. In this experiment 148Gd, 238U, 230Th, 239Pu and 244Cm alpha particle emitters were used. The values for alpha particle energy resolution, the linear response to energy, the confidence in the results and the automatisation of the procedure make this method a promising analysis system.

  4. Measurement of Low Energy Electronic Recoil Response and Electronic/Nuclear Recoils Discrimination in XENON100

    NASA Astrophysics Data System (ADS)

    Ye, Jingqiang; Xenon Collaboration

    2017-01-01

    The XENON100 detector uses liquid xenon time projection chamber to search for nuclear recoils(NR) caused by hypothetical Weakly Interacting Massive Particles (WIMPs). The backgrounds are mostly electronic recoils(ER), thus it's crucial to distinguish NR from ER. Using high statistical calibration data from tritiated methane, AmBe and other sources in XENON100, the ER/NR discrimination under different electric fields are measured. The Photon yield and recombination fluctuation of low energy electronic recoils under different fields will also be presented and compared to results from NEST and other experiments, which is crucial to understanding the response of liquid xenon detectors in the energy regime of searching dark matter.

  5. Measurement techniques in dry-powdered processing of spent nuclear fuels.

    SciTech Connect

    Bowers, D. L.; Hong, J.-S.; Kim, H.-D.; Persiani, P. J.; Wolf, S. F.

    1999-07-21

    High-performance liquid chromatography (HPLC) with inductively coupled plasma mass spectrometry (ICPMS) detection, {alpha}-spectrometry ({alpha}-S), and {gamma}-spectrometry ({gamma}-S) were used for the determination of nuclide content in five samples excised from a high-burnup fuel rod taken from a pressurized water reactor (PWR). The samples were prepared for analysis by dissolution of dry-powdered samples. The measurement techniques required no separation of the plutonium, uranium, and fission products. The sample preparation and analysis techniques showed promise for in-line analysis of highly-irradiated spent fuels in a dry-powdered process. The analytical results allowed the determination of fuel burnup based on {sup 148}Nd, Pu, and U content. A goal of this effort is to develop the HPLC-ICPMS method for direct fissile material accountancy in the dry-powdered processing of spent nuclear fuel.

  6. Absolute measurement of spatial and spectral characteristics of bremsstrahlung using the photoexcitation of nuclear isomers

    NASA Astrophysics Data System (ADS)

    Carroll, J. J.; Richmond, D. G.; Sinor, T. W.; Taylor, K. N.; Hong, C.; Standifird, J. D.; Collins, C. B.; Huxel, N.; von Neumann-Cosel, P.; Richter, A.

    1993-08-01

    A method of obtaining absolute, direct measurements of the spatial and spectral characteristics of bremsstrahlung is discussed. This technique, called x-ray activation of nuclei (XAN) is based on the use of well-known photonuclear reactions which populate long-lived nuclear isomers. These populations sample incident photon continua at discrete excitation energies and effectively store this information for convenient retrieval following the irradiation of gram-sized targets. Recently a series of experiments has been conducted which has significantly expanded the available data for the photoexcitation of a wide range of isomers at higher energies. Thus it has become feasible to extend the use of XAN to energies approaching 4 MeV. The utility of this technique is demonstrated by the characterization of bremsstrahlung from the newly installed research linac at the University of Texas at Dallas.

  7. Nuclear reaction measurements on tissue-equivalent materials and GEANT4 Monte Carlo simulations for hadrontherapy.

    PubMed

    De Napoli, M; Romano, F; D'Urso, D; Licciardello, T; Agodi, C; Candiano, G; Cappuzzello, F; Cirrone, G A P; Cuttone, G; Musumarra, A; Pandola, L; Scuderi, V

    2014-12-21

    When a carbon beam interacts with human tissues, many secondary fragments are produced into the tumor region and the surrounding healthy tissues. Therefore, in hadrontherapy precise dose calculations require Monte Carlo tools equipped with complex nuclear reaction models. To get realistic predictions, however, simulation codes must be validated against experimental results; the wider the dataset is, the more the models are finely tuned.Since no fragmentation data for tissue-equivalent materials at Fermi energies are available in literature, we measured secondary fragments produced by the interaction of a 55.6 MeV u(-1) (12)C beam with thick muscle and cortical bone targets. Three reaction models used by the Geant4 Monte Carlo code, the Binary Light Ions Cascade, the Quantum Molecular Dynamic and the Liege Intranuclear Cascade, have been benchmarked against the collected data. In this work we present the experimental results and we discuss the predictive power of the above mentioned models.

  8. Computed Tomography and Nuclear Magnetic Resonance to study the internal structure and measure weathering

    NASA Astrophysics Data System (ADS)

    Zornoza-Indart, A.; Lopez-Arce, P.; Alvarez de Buergo, M.; Fort, R.

    2012-04-01

    internal damage allowing to measure non visible structural weathering and also to analyze surface damage due to 3D reconstructions of the samples. MRI results show higher T1 and T2 values in samples subjected to salt crystallization and freezing and thawing cycles than in samples subjected to thermal shock and marine aerosol ageing test meaning the presence of larger pores in these specimens. This results correlate with the results obtained by X ray Computed Tomography analysis where a dramatic internal damage is observed in samples subjected to salt crystallization and freezing and thawing cycles while in the other samples the damage concentrates in the surface. Nuclear Magnetic Resonance and X ray Computed Tomography proved to be powerful non-destructive techniques for study the internal structure and measure weathering.

  9. Heat Transfer in Waste Glass Melts - Measurement and Implications for Nuclear Waste Vitrification

    NASA Astrophysics Data System (ADS)

    Wang, Chuan

    Thermal properties of waste glass melts, such as high temperature density and thermal conductivity, are relevant to heat transfer processes in nuclear waste vitrification. Experimental measurement techniques were developed and applied to four nuclear waste glasses representative of those currently projected for treatment of Hanford HLW and LAW streams to study heat flow mechanisms in nuclear waste vitrification. Density measurement results by Archimedes' method indicated that densities of the melts investigated varied considerably with composition and temperature. Thermal diffusivities of waste melts were determined at nominal melter operating temperatures using a temperature-wave technique. Thermal conductivities were obtained by combining diffusivity data with the experimentally-acquired densities of the melts and their known heat capacities. The experimental results display quite large positive dependences of conductivities on temperature for some samples and much weaker positive temperature dependences for others. More importantly, there is observed a big change in the slopes of the conductivities versus temperature as temperature is increased for two of the melts, but not for the other two. This behavior was interpreted in terms of the changing contributions of radiation and conduction with temperature and composition dependence of the absorption coefficient. Based on the obtained thermal conductivities, a simple model for a waste glass melter was set up, which was used to analyze the relative contributions of conduction and radiation individually and collectively to the overall heat flow and to investigate factors and conditions that influence the radiation contribution to heat flow. The modeling results showed that unlike the case at lower temperatures, the radiant energy flow through waste melts could be predominant compared with conduction at temperature of about 900 °C or higher. However, heat flow due to radiation was roughly equal to that from

  10. Filter Measurement System for Nuclear Material Storage Canisters. End of Year Report FY 2013

    SciTech Connect

    Moore, Murray E.; Reeves, Kirk P.

    2014-02-03

    A test system has been developed at Los Alamos National Laboratory to measure the aerosol collection efficiency of filters in the lids of storage canisters for special nuclear materials. Two FTS (filter test system) devices have been constructed; one will be used in the LANL TA-55 facility with lids from canisters that have stored nuclear material. The other FTS device will be used in TA-3 at the Radiation Protection Division’s Aerosol Engineering Facility. The TA-3 system will have an expanded analytical capability, compared to the TA-55 system that will be used for operational performance testing. The LANL FTS is intended to be automatic in operation, with independent instrument checks for each system component. The FTS has been described in a complete P&ID (piping and instrumentation diagram) sketch, included in this report. The TA-3 FTS system is currently in a proof-of-concept status, and TA-55 FTS is a production-quality prototype. The LANL specification for (Hagan and SAVY) storage canisters requires the filter shall “capture greater than 99.97% of 0.45-micron mean diameter dioctyl phthalate (DOP) aerosol at the rated flow with a DOP concentration of 65±15 micrograms per liter”. The percent penetration (PEN%) and pressure drop (DP) of fifteen (15) Hagan canister lids were measured by NFT Inc. (Golden, CO) over a period of time, starting in the year 2002. The Los Alamos FTS measured these quantities on June 21, 2013 and on Oct. 30, 2013. The LANL(6-21-2013) results did not statistically match the NFT Inc. data, and the LANL FTS system was re-evaluated, and the aerosol generator was replaced and the air flow measurement method was corrected. The subsequent LANL(10-30-2013) tests indicate that the PEN% results are statistically identical to the NFT Inc. results. The LANL(10-30-2013) pressure drop measurements are closer to the NFT Inc. data, but future work will be investigated. An operating procedure for the FTS (filter test system) was written, and

  11. Traceability for measurements of radioactivity in waste materials arising from nuclear site decommissioning

    NASA Astrophysics Data System (ADS)

    Dean, Julian C. J.; Adsley, Ian; Burgess, Peter H.

    2007-08-01

    Site decommissioning is now a major aspect of the work of the nuclear industry worldwide. One of its many technical challenges is the need to measure levels of radioactivity in a range of materials (e.g. concrete, brick and steel) in order that radioactive waste may be identified, sentenced and consigned to the appropriate waste stream in accordance with national regulations. This is done using any of a number of measurement techniques, falling under three categories: (i) bulk monitoring (for γ and neutron emitters), (ii) surface monitoring (predominantly for α and β emitters) and (iii) radiochemical analysis. The last is often used to determine a 'radionuclide fingerprint' for a particular operational area for use in conjunction with data from in situ monitoring. Traceability to national standards can be difficult to demonstrate for measurements of this type. Only a limited number of standards and reference materials are available, and their chemical and physical forms do not match those of the very wide range of samples being measured. Traceability for surface measurements is further complicated by the subjective nature of monitoring using hand-held detectors. This paper describes some of the detector types used for γ non-destructive assay (NDA) and for surface measurements, gives examples of currently available standards and calibration procedures and provides some guidance in how to achieve traceability. A generic analysis regime for an operational area is presented which demonstrates points where traceability can, in principle, be attained. A new methodology for developing 'realistic' large-volume standard sources, traceable to national standards, has been developed by the National Physical Laboratory (NPL), and this is described.

  12. 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.

  13. Systematic and Statistical Errors Associated with Nuclear Decay Constant Measurements Using the Counting Technique

    NASA Astrophysics Data System (ADS)

    Koltick, David; Wang, Haoyu; Liu, Shih-Chieh; Heim, Jordan; Nistor, Jonathan

    2016-03-01

    Typical nuclear decay constants are measured at the accuracy level of 10-2. There are numerous reasons: tests of unconventional theories, dating of materials, and long term inventory evolution which require decay constants accuracy at a level of 10-4 to 10-5. The statistical and systematic errors associated with precision measurements of decays using the counting technique are presented. Precision requires high count rates, which introduces time dependent dead time and pile-up corrections. An approach to overcome these issues is presented by continuous recording of the detector current. Other systematic corrections include, the time dependent dead time due to background radiation, control of target motion and radiation flight path variation due to environmental conditions, and the time dependent effects caused by scattered events are presented. The incorporation of blind experimental techniques can help make measurement independent of past results. A spectrometer design and data analysis is reviewed that can accomplish these goals. The author would like to thank TechSource, Inc. and Advanced Physics Technologies, LLC. for their support in this work.

  14. First measurement of proton-induced low-momentum dielectron radiation off cold nuclear matter

    NASA Astrophysics Data System (ADS)

    HADES Collaboration; Agakishiev, G.; Balanda, A.; Belver, D.; Belyaev, A.; Berger-Chen, J. C.; Blanco, A.; Böhmer, M.; Boyard, J. L.; Cabanelas, P.; Chernenko, S.; Dybczak, A.; Epple, E.; Fabbietti, L.; Fateev, O.; Finocchiaro, P.; Fonte, P.; Friese, J.; Fröhlich, I.; Galatyuk, T.; Garzón, J. A.; Gernhäuser, R.; Göbel, K.; Golubeva, M.; González-Díaz, D.; Guber, F.; Gumberidze, M.; Heinz, T.; Hennino, T.; Holzmann, R.; Ierusalimov, A.; Iori, I.; Ivashkin, A.; Jurkovic, M.; Kämpfer, B.; Karavicheva, T.; Koenig, I.; Koenig, W.; Kolb, B. W.; Kornakov, G.; Kotte, R.; Krása, A.; Krizek, F.; Krücken, R.; Kuc, H.; Kühn, W.; Kugler, A.; Kurepin, A.; Ladygin, V.; Lalik, R.; Lang, S.; Lapidus, K.; Lebedev, A.; Liu, T.; Lopes, L.; Lorenz, M.; Maier, L.; Mangiarotti, A.; Markert, J.; Metag, V.; Michalska, B.; Michel, J.; Mishra, D.; Müntz, C.; Naumann, L.; Pachmayer, Y. C.; Palka, M.; Parpottas, Y.; Pechenov, V.; Pechenova, O.; Pietraszko, J.; Przygoda, W.; Ramstein, B.; Reshetin, A.; Rustamov, A.; Sadovsky, A.; Salabura, P.; Schmah, A.; Schwab, E.; Siebenson, J.; Sobolev, Yu. G.; Spataro, S.; Spruck, B.; Ströbele, H.; Stroth, J.; Sturm, C.; Tarantola, A.; Teilab, K.; Tlusty, P.; Traxler, M.; Trebacz, R.; Tsertos, H.; Vasiliev, T.; Wagner, V.; Weber, M.; Wendisch, C.; Wüstenfeld, J.; Yurevich, S.; Zanevsky, Y.

    2012-09-01

    We present data on dielectron emission in proton induced reactions on a Nb target at 3.5 GeV kinetic beam energy measured with HADES installed at GSI. The data represent the first high statistics measurement of proton-induced dielectron radiation from cold nuclear matter in a kinematic regime, where strong medium effects are expected. Combined with the good mass resolution of 2%, it is the first measurement sensitive to changes of the spectral functions of vector mesons, as predicted by models for hadrons at rest or small relative momenta. Comparing the e+e- invariant mass spectra to elementary p + p data, we observe for e+e- momenta Pee<0.8 GeV/c a strong modification of the shape of the spectrum, which we attribute to an additional ρ-like contribution and a decrease of ω yield. These opposite trends are tentatively interpreted as a strong coupling of the ρ meson to baryonic resonances and an absorption of the ω meson, which are two aspects of in-medium modification of vector mesons.

  15. Aerial measurements of artificial radionuclides in Germany in case of a nuclear accident.

    PubMed

    Winkelmann, I; Strobl, C; Thomas, M

    2004-01-01

    Gamma-ray spectrometric systems carried by helicopters prove to be indispensable for the surveillance of environmental radioactivity. The aerial measurements are an important tool for rapid and large-scale nuclide specific determination of soil contamination after an accidental release of radionuclides from a nuclear facility. Furthermore this technique is also applied for the determination of anomalies of elevated radioactivity of natural radionuclides, the detection of lost radioactive sources and geological mapping. For the measurements the helicopters are equipped with a NaI(Tl)-detector array and a high purity germanium-semiconductor (HPGe) detector. Especially with the HPGe-detector it is possible to clearly identify individual radionuclides. To improve and to guarantee the quality of this method several exercises with different fields of interest have been carried out during the last years. Thereby the main focus is on the improvement of the instrumentation, data handling and data analysis. The results of the airborne radionuclide measurements from the Black Forest which was performed in co-operation with the Swiss National Emergency Operation Centre, are presented here. During this exercise the gamma dose rate, soil contamination due to 137Cs and the specific activities of natural radionuclides in soil were determined.

  16. Measurement of hydrogen and lithium ion energy densities on PBFA II using direct nuclear activation diagnostics

    NASA Astrophysics Data System (ADS)

    Ruiz, C. L.; Cooper, G. W.; Chambers, G.; Schmidlapp, F. A.

    1997-01-01

    In the light-ion-beam fusion program at Sandia National Laboratories an intense lithium beam is being developed to drive inertial confinement fusion targets. An important issue is the purity of the beam. To assess this concern, direct nuclear activation diagnostics based on the reactions 7Li(p,n)7Be, 10B(p,α)7Be, and 19F(7Li,d)24Na were fielded to measure the energy densities of hydrogen and lithium in the beam. The hydrogen beam energy density was measured to be less than 2% of the lithium beam energy density on a majority (10) of the 19 LiF anode shots taken and was always less than 10%. The total hydrogen energy in the beam ranged from only 0.5-10 kJ. Over this shot series increasing efforts were made to clean the anode prior to each shot. In general, there was a modest reduction in the hydrogen energy fraction with improved cleaning, but no corresponding increase in the lithium energy density was seen. The lithium energy density as a function of location was also measured and found to typically vary by factors of 1.5-4 over the diode.

  17. Measuring relative acetylcholine receptor agonist binding by selective proton nuclear magnetic resonance relaxation experiments.

    PubMed Central

    Behling, R W; Yamane, T; Navon, G; Sammon, M J; Jelinski, L W

    1988-01-01

    A method is presented that uses selective proton Nuclear Magnetic Resonance (NMR) relaxation measurements of nicotine in the presence of the acetylcholine receptor to obtain relative binding constants for acetylcholine, carbamylcholine, and muscarine. For receptors from Torpedo californica the results show that (a) the binding constants are in the order acetylcholine greater than nicotine greater than carbamylcholine greater than muscarine; (b) selective NMR measurements provide a rapid and direct method for monitoring both the specific and nonspecific binding of agonists to these receptors and to the lipid; (c) alpha-bungarotoxin can be used to distinguish between specific and nonspecific binding to the receptor; (d) the receptor--substrate interaction causes a large change in the selective relaxation time of the agonists even at concentrations 100x greater than that of the receptor. This last observation means that these measurements provide a rapid method to monitor drug binding when only small amounts of receptor are available. Furthermore, the binding strategies presented here may be useful for the NMR determination of the conformation of the ligand in its bound state. Images FIGURE 1 PMID:3395661

  18. phi meson measurements and flavor-dependent nuclear suppression at RHIC-PHENIX

    NASA Astrophysics Data System (ADS)

    Kijima, Kotaro M.; PHENIX Collaboration

    2010-09-01

    Measurement of low mass vector mesons (ρ, ω, phi) provides important information to understand the properties of quark-gluon plasma (QGP) created in the central heavy-ion collision at RHIC. The mass and branching ratio of the phi meson decay into di-electron and di-kaon could be modified in the excited vacuum due to the effect of partial chiral symmetry restoration. In addition, phi meson contains hidden strangeness and hence its measurement can figure out the strangeness production. The suppression pattern of phi meson with high transverse momentum in heavy-ion collisions, compared to scaled p + p results, provides the information to understand the mechanism of production and energy loss of strange quark with the strongly coupled matter. The PHENIX experiment at RHIC has measured the phi meson production in p+p, d+Au and Au+Au collisions at \\sqrt{s_{NN}} up to 200 GeV at mid-rapidity. In this paper, we will present recent PHENIX results about the phi meson production. The mass peaks for phi have been observed in both di-electron and di-kaon invariant mass spectra. The extracted spectra, mass and width of phi in p+p, d+Au and Au+Au are reviewed. Moreover, we compare the nuclear modification factors of various hadrons and discuss flavor dependence of their suppression patterns.

  19. Sensitivity of MR Diffusion Measurements to Variations in Intracellular Structure: Effects of Nuclear Size

    PubMed Central

    Xu, Junzhong; Does, Mark D.; Gore, John C.

    2009-01-01

    Magnetic resonance imaging measurements of the apparent rate of water diffusion in tumors are sensitive to variations in tissue cellularity, which have been shown useful for characterizing tumors and their responses to treatments. However, because of technical limitations on most MRI systems, conventional pulse gradient spin echo (PGSE) methods measure relatively long time scales, during which water molecules may encounter diffusion barriers at multiple spatial scales, including those much greater than typical cell dimensions. As such they cannot distinguish changes on sub-cellular scales from gross changes in cell density. Oscillating gradient spin echo (OGSE) methods have the potential to distinguish effects on restriction at much shorter time and length scales. Both PGSE and OGSE methods have been studied numerically by simulating diffusion in a three-dimensional, multi-compartment tissue model. The results show that conventional measurements with the PGSE method cannot selectively probe variations over short length scales and, therefore, are relatively insensitive to intracellular structure, whereas results using OGSE methods at moderate gradient frequencies are affected by variations in cell nuclear sizes and can distinguish tissues that differ only over sub-cellular length scales. This additional sensitivity suggests that OGSE imaging may have significant advantages over conventional PGSE methods for characterizing tumors. PMID:19205020

  20. In Situ Measurement of Surface Functional Groups on Silica Nanoparticles Using Solvent Relaxation Nuclear Magnetic Resonance.

    PubMed

    Yuan, Li; Chen, Lan; Chen, Xiaohong; Liu, Renxiao; Ge, Guanglu

    2017-09-05

    In situ analysis and study on the surface of nanoparticles (NPs) is a key to obtain their important physicochemical properties for the subsequent applications. Of them, most works focus on the qualitative characterization whereas quantitative analysis and measurement on the NPs under their storage and usage conditions is still a challenge. In order to cope with this challenge, solvation relaxation-based nuclear magnetic resonance (NMR) technology has been applied to measure the wet specific surface area and, therefore, determine the number of the bound water molecules on the surface of silica NPs in solution and the hydrophilic groups of various types grafted on the surface of the NPs. By changing the surface functional group on silica particles, the fine distinction for the solvent-particle interaction with different surface group can be quantitatively differentiated by measuring the number of water molecules absorbed on the surface. The results show that the number of the surface hydroxyl, amine, and carboxyl group per nm(2) is 4.0, 3.7, and 2.3, respectively, for the silica particles with a diameter of 203 nm. The method reported here is the first attempt to determine in situ the number of bound solvent molecules and any solvophilic groups grafted on nanoparticles.

  1. Feasibility study of measuring the 229Th nuclear isomer transition with 233U-doped crystals

    NASA Astrophysics Data System (ADS)

    Stellmer, Simon; Schreitl, Matthias; Kazakov, Georgy A.; Sterba, Johannes H.; Schumm, Thorsten

    2016-07-01

    We propose a simple approach to measure the energy of the few-eV isomeric state in 229Th. To this end, 233U nuclei are doped into VUV-transparent crystals, where they undergo α decay into 229Th, and, with a probability of 2%, populate the isomeric state. These Thm229 nuclei may decay into the nuclear ground state under emission of the sought-after VUV γ ray, whose wavelength can be determined with a spectrometer. Based on measurements of the optical transmission of 238U:CaF2 crystals in the VUV range, we expect a signal at least two orders of magnitude larger compared to current schemes using surface implantation of recoil nuclei. The signal background is dominated by Cherenkov radiation induced by β decays of the thorium decay chain. We estimate that, even if the isomer undergoes radiative de-excitation with a probability of only 0.1%, the VUV γ ray can be detected within a reasonable measurement time.

  2. Monitoring of pipelines in nuclear power plants by measuring laser-based mechanical impedance

    NASA Astrophysics Data System (ADS)

    Lee, Hyeonseok; Sohn, Hoon; Yang, Suyoung; Yang, Jinyeol

    2014-06-01

    Using laser-based mechanical impedance (LMI) measurement, this study proposes a damage detection technique that enables structural health monitoring of pipelines under the high temperature and radioactive environments of nuclear power plants (NPPs). The applications of conventional electromechanical impedance (EMI) based techniques to NPPs have been limited, mainly due to the contact nature of piezoelectric transducers, which cannot survive under the high temperature and high radiation environments of NPPs. The proposed LMI measurement technique aims to tackle the limitations of the EMI techniques by utilizing noncontact laser beams for both ultrasound generation and sensing. An Nd:Yag pulse laser is used for ultrasound generation, and a laser Doppler vibrometer is employed for the measurement of the corresponding ultrasound responses. For the monitoring of pipes covered by insulation layers, this study utilizes optical fibers to guide the laser beams to specific target locations. Then, an outlier analysis is adopted for autonomous damage diagnosis. Validation of the proposed LMI technique is carried out on a carbon steel pipe elbow under varying temperatures. A corrosion defect chemically engraved in the specimen is successfully detected.

  3. Time-of-flight mass measurements for nuclear processes in neutron star crusts

    SciTech Connect

    Estrade, Alfredo; Matos, M.; Schatz, Hendrik; Amthor, A. M.; Bazin, D.; Beard, Mary; Becerril, A.; Brown, Edward; Elliot, T; Gade, A.; Galaviz, D.; George, S.; Gupta, Sanjib; Hix, William Raphael; Lau, Rita; Moeller, Peter; Pereira, J.; Portillo, M.; Rogers, A. M.; Shapira, Dan; Smith, E.; Stolz, A.; Wallace, M.; Wiescher, Michael

    2011-01-01

    The location of electron capture heat sources in the crust of accreting neutron stars depends on the masses of extremely neutron-rich nuclei. We present first results from a new implementation of the time-of-flight technique to measure nuclear masses of rare isotopes at the National Supercon- ducting Cyclotron Laboratory. The masses of 16 neutron-rich nuclei in the Sc Ni element range were determined simultaneously, improving the accuracy compared to previous data in 12 cases. The masses of 61V, 63Cr, 66Mn, and 74Ni were measured for the first time with mass excesses of 30.510(890) MeV, 35.280(650) MeV, 36.900(790) MeV, and 49.210(990) MeV, respectively. With the measurement of the 66Mn mass, the location of the two dominant heat sources in the outer crust of accreting neutron stars, which exhibit so called superbursts, is now experimentally constrained. We find that the location of the 66Fe 66Mn electron capture transition occurs sig- nificantly closer to the surface than previously assumed because our new experimental Q-value is 2.1 MeV smaller than predicted by the FRDM mass model. The results also provide new insights into the structure of neutron-rich nuclei around N = 40.

  4. First measurement of nuclear recoil head-tail sense in a fiducialised WIMP dark matter detector

    NASA Astrophysics Data System (ADS)

    Battat, J. B. R.; Daw, E.; Ezeribe, A. C.; Gauvreau, J.-L.; Harton, J. L.; Lafler, R.; Lee, E. R.; Loomba, D.; Lumnah, A.; Miller, E. H.; Mouton, F.; Murphy, A. StJ.; Paling, S. M.; Phan, N. S.; Robinson, M.; Sadler, S. W.; Scarff, A.; Schuckman, F. G., II; Snowden-Ifft, D. P.; Spooner, N. J. C.

    2016-10-01

    Recent computational results suggest that directional dark matter detectors have potential to probe for WIMP dark matter particles below the neutrino floor. The DRIFT-IId detector used in this work is a leading directional WIMP search time projection chamber detector. We report the first measurements of the detection of the directional nuclear recoils in a fully fiducialised low-pressure time projection chamber. In this new operational mode, the distance between each event vertex and the readout plane is determined by the measurement of minority carriers produced by adding a small amount of oxygen to the nominal CS2+CF4 target gas mixture. The CS2+CF4+O2 mixture has been shown to enable background-free operation at current sensitivities. Sulfur, fluorine, and carbon recoils were generated using neutrons emitted from a 252Cf source positioned at different locations around the detector. Measurement of the relative energy loss along the recoil tracks allowed the track vector sense, or the so-called head-tail asymmetry parameter, to be deduced. Results show that the previously reported observation of head-tail sensitivity in pure CS2 is well retained after the addition of oxygen to the gas mixture.

  5. Is the nuclear refractive index lower than cytoplasm? Validation of phase measurements and implications for light scattering technologies.

    PubMed

    Steelman, Zachary A; Eldridge, Will J; Weintraub, Jacob B; Wax, Adam

    2017-04-18

    The refractive index (RI) of biological materials is a fundamental parameter for the optical characterization of living systems. Numerous light scattering technologies are grounded in a quantitative knowledge of the refractive index at cellular and subcellular scales. Recent work in quantitative phase microscopy (QPM) has called into question the widely held assumption that the index of the cell nucleus is greater than that of the cytoplasm, a result which disagrees with much of the current literature. In this work, we critically examine the measurement of the nuclear and whole-cell refractive index using QPM, validating that nuclear refractive index is lower than that of cytoplasm in four diverse cell lines and their corresponding isolated nuclei. We further examine Mie scattering and phase-wrapping as potential sources of error in these measurements, finding they have minimal impact. Finally, we use simulation to examine the effects of incorrect RI assumptions on nuclear morphology measurements using angle-resolved scattering information. Despite an erroneous assumption of the nuclear refractive index, accurate measurement of nuclear morphology was maintained, suggesting that light scattering modalities remain effective. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Characterization of organic contaminants in porous media using nuclear magnetic resonance and spectral induced polarization measurements.

    NASA Astrophysics Data System (ADS)

    Rupert, Y. K.

    2015-12-01

    The remediation and monitoring of soils and groundwater contaminated with organic compounds is an important goal of many environmental restoration efforts. This laboratory research focuses on combining two innovative geophysical methods: nuclear magnetic resonance (NMR) and spectral induced polarization (SIP) to assess their suitability to characterize and quantify organic contaminants in porous media. Toluene, a light non-aqueous phase liquid (LNAPL), and ethoxy-nonafluorobutane, an engineered dense non-aqueous phase liquid (DNAPL), have been selected as representative organic contaminants. Low-field NMR relaxation time (T2) measurements and diffusion-relaxation (D-T2) correlation measurements, as well as low frequency SIP measurements (<10 kHz) are performed to quantify the amount of these two organic compounds in the presence of water in three types of porous media (sands, clay, and various sand-clay mixtures). The T2, D-T2, and SIP measurements are made on water, toluene, and the synthetic DNAPL in each porous media to understand the effect of different porous media on the NMR and SIP responses in each fluid. We then plan to make measurements on water-organic mixtures with varied concentrations of organic compounds in each porous medium to resolve the NMR and SIP response of the organic contaminants from that of water and to quantify the amount of organic contaminants. Building a relationship between SIP and NMR signatures from organic contaminants not only provides a fundamental yet important petrophysical relationship, but also builds a framework for continued investigation into how these two methods synergize. This will also provide spatially dense information about organic contaminated natural sediments at scales that will improve the quantitative characterization and remediation of contaminated sites.The remediation and monitoring of soils and groundwater contaminated with organic compounds is an important goal of many environmental restoration efforts

  7. Measuring microbial metabolism in atypical environments: Bentonite in used nuclear fuel storage.

    PubMed

    Stone, Wendy; Kroukamp, Otini; Moes, Ana; McKelvie, Jennifer; Korber, Darren R; Wolfaardt, Gideon M

    2016-01-01

    Genomics enjoys overwhelming popularity in the study of microbial ecology. However, extreme or atypical environments often limit the use of such well-established tools and consequently demand a novel approach. The bentonite clay matrix proposed for use in Deep Geological Repositories for the long-term storage of used nuclear fuel is one such challenging microbial habitat. Simple, accessible tools were developed for the study of microbial ecology and metabolic processes that occur within this habitat, since the understanding of the microbiota-niche interaction is fundamental to describing microbial impacts on engineered systems such as compacted bentonite barriers. Even when genomic tools are useful for the study of community composition, techniques to describe such microbial impacts and niche interactions should complement these. Tools optimised for assessing localised microbial activity within bentonite included: (a) the qualitative use of the resazurin-resorufin indicator system for redox localisation, (b) the use of a CaCl2 buffer for the localisation of pH, and (c) fluorometry for the localisation of precipitated sulphide. The use of the Carbon Dioxide Evolution Monitoring System was also validated for measuring microbial activity in desiccated and saturated bentonite. Finally, the buffering of highly-basic bentonite at neutral pH improved the success of isolation of microbial populations, but not DNA, from the bentonite matrix. Thus, accessible techniques were optimised for exploring microbial metabolism in the atypical environments of clay matrices and desiccated conditions. These tools have application to the applied field of used nuclear fuel management, as well as for examining the fundamental biogeochemical cycles active in sedimentary and deep geological environments. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. A performance evaluation of 90Y dose-calibrator measurements in nuclear pharmacies and clinics in the United States.

    PubMed

    Schultz, Michael K; Cessna, Jeffrey T; Anderson, Tamara L; Ponto, James A; Petry, Neil; Kowalsky, Richard J; Palmer, Matthew R; Beinlich, Uwe F; Baker, William; Hinkle, George H; Hung, Joseph C; Quinton, Timothy; Rice, Peter A; Divgi, Chaitanya; Norenberg, Jeffrey P

    2008-02-01

    A blind performance test was conducted to evaluate dose-calibrator measurements at nuclear pharmacies in the United States (US). Two test-sample geometries were chosen to represent those used for measurements of 90Y-ibritumomab tiuxetan (ZEVALIN). The radioactivity concentration of test-samples was verified by the US National Institute of Standards and Technology. Forty-five results were reported by 10 participants. Eighty percent of reported values were within the US Pharmacopoeia content standard (+/-10%) for 90Y-ZEVALIN. All results were within US Nuclear Regulatory Commission conformance limits (+/-20%) for defining therapeutic misadministrations.

  9. US-Russian Cooperation in Upgrading MC&A System at Rosatom Facilities: Measurement of Nuclear Materials

    SciTech Connect

    Powell, Danny H; Jensen, Bruce A

    2011-01-01

    Improve protection of weapons-usable nuclear material from theft or diversion through the development and support of a nationwide sustainable and effective Material Control and Accountability (MC&A) program based on material measurement. The material protection, control, and accountability (MPC&A) cooperation has yielded significant results in implementing MC&A measurements at Russian nuclear facilities: (1) Establishment of MEM WG and MEMS SP; (2) Infrastructure for development, certification, and distribution of RMs; and (3) Coordination on development and implementation of MMs.

  10. Material accountancy measurement techniques in dry-powdered processing of nuclear spent fuels.

    SciTech Connect

    Wolf, S. F.

    1999-03-24

    The paper addresses the development of inductively coupled plasma-mass spectrometry (ICPMS), thermal ionization-mass spectrometry (TIMS), alpha-spectrometry, and gamma spectrometry techniques for in-line analysis of highly irradiated (18 to 64 GWD/T) PWR spent fuels in a dry-powdered processing cycle. The dry-powdered technique for direct elemental and isotopic accountancy assay measurements was implemented without the need for separation of the plutonium, uranium and fission product elements in the bulk powdered process. The analyses allow the determination of fuel burn-up based on the isotopic composition of neodymium and/or cesium. An objective of the program is to develop the ICPMS method for direct fissile nuclear materials accountancy in the dry-powdered processing of spent fuel. The ICPMS measurement system may be applied to the KAERI DUPIC (direct use of spent PWR fuel in CANDU reactors) experiment, and in a near-real-time mode for international safeguards verification and non-proliferation policy concerns.

  11. Establishing protective long term measures after severe nuclear accidents using multiple criteria.

    PubMed

    Papazoglou, I A; Kollas, J G

    1997-05-01

    This paper proposes a methodology supporting decisions on protective measures following severe nuclear accidents and demonstrates its use. A multicriteria decision analysis approach is adopted where value tradeoffs are postponed until the very last stage of the decision process. All feasible solutions are implicitly considered and evaluated in the chosen criteria. Technically inferior solutions are excluded. Only the non-dominated or efficient solutions forming the "efficient frontier" are retained and presented to the decision makers. Implementation of inefficient solutions is in this way avoided. A choice among the efficient solutions, although it implies value tradeoffs among the multiple criteria, avoids the direct and apriori assessment of preferences. An interactive computer package has been developed with which the decision maker can choose a point on the efficient frontier in the consequence space and immediately see the corresponding alternative in the decision space. The methodology is demonstrated through an application on the choice among possible protective measures in contaminated areas of the former USSR after the Chernobyl accident using as criteria the collective effective life-time dose received by the population and the cost associated with each possible decision.

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

    NASA Astrophysics Data System (ADS)

    Behr, J. A.; Craiciu, I.; Gorelov, A.; Smale, S.; Warner, C. L.; Lawrence, L.; Fenker, B.; Behling, R. S.; Mehlman, M.; Melconian, D.; Gwinner, G.; Anholm, M.; McNeil, J.; Ashery, D.; Cohen, I.

    2016-09-01

    We have spin-polarized laser cooled 37K by direct optical pumping and measured the polarization to < 0 . 1 % accuracy [B. Fenker arXiv:1602.04526]. Our polarization method naturally monitors the polarization of the nuclei as they decay. The atoms absorb circularly polarized light directed along the quantization axis near-resonant with the atomic S1 / 2 to P1 / 2 transition. Once the atoms are polarized, they stop absorbing light, so the ratio between the final P1 / 2 population and its initial maximum probes the degree of polarization. We monitor the P1 / 2 population using UV photons energetic enough to photoionize the P1 / 2 state but not the S1 / 2 state. Since the final P1 / 2 population nearly vanishes, 5% precision on the final/maximum ratio determines the polarization to 0.1%. We eliminate a nonclassical effect, coherent population trapping, which could produce poorly polarized unexcited atoms. We show planned upgrades. Our result for the nuclear vector polarization during our Aβ measurement [B. Fenker, this conference] was 99.13(9)%, not the dominant systematic. Supported by NSERC, D.O.E., Israel Science Foundation. TRIUMF receives federal funding via a contribution agreement with the National Research Council of Canada.

  13. The phonon density of states measured with synchrotron radiation and nuclear resonances.

    SciTech Connect

    Sturhahn, W.; Hu, M.; Shastri, S.; Toellner, T.

    2001-01-26

    In this experiment, we will use synchrotron radiation to measure the density of states of vibrational excitations (phonons.) Each group of students will conduct an experiment at sector 3-ID of the Advanced Photon Source, the nation's premier synchrotron radiation facility. We provide one support staff per group, i.e., Drs. Michael Hu, Sarvjit Shastri, Wolfgang Sturhahn, and Tom Toellner will help their group to perform the experiment and interpret the data. After data collection (1-2 h per group), the remaining time will be spent with evaluation and interpretation. In addition to your own data, we provide similar sets of data. Computer hardware (iMac running as X-terminals) and software for data manipulation will be provided. It is important that you understand the basic principles of the experimental method. Therefore we strongly recommend that you read the next section and the attached article Phonon Density of States Measured by Inelastic Nuclear Resonant Scattering. You are expected to use this description to familiarize yourself with the experimental setup and its individual components before the start of the experiment. You should be able to solve at least 75% of the quiz correctly. If you have particular questions or a general problem in understanding this document, please contact Dr. W. Sturhahn, Bldg. 431, Rm. D007, tel. 0163.

  14. Statistical analyses of nuclear waste level measurements to estimate retained gas volumes

    NASA Astrophysics Data System (ADS)

    Whitney, Paul D.; Chen, Guang

    1999-01-01

    The Hanford site is home to 177 large, underground nuclear waste storage tanks. Numerous safety and environmental concerns around these tanks and their contents. One such concern is the propensity for the waste in these tanks to generate and retain flammable gases. The surface level of the waste in these tanks is routinely monitored to assess whether the tanks are leaking. For some of the tanks, the waste surface level measurements synchronously fluctuated with atmospheric pressure changes. The current best explanation for these synchronous fluctuations is that the waste contains gas-phase material that changes volume in response to the atmospheric pressure changes. This paper describes: (1) The exploratory data analysis that led to the discovery of the phenomena; (2) A physical mode based on the ideal gas law that explains the phenomena. Additionally, the model allows one to obtain estimates of the retained gas volume in the tank waste; (3) A statistical procedure for detecting retained gas based on the physical model and tank surface level measurements; and (4) A Kalman filter model for analyzing the dynamics of retained gas. It's also shown how the filter can be used to detect abrupt changes in the system.

  15. Revised rates for the stellar triple-α process from measurement of 12C nuclear resonances

    NASA Astrophysics Data System (ADS)

    Fynbo, Hans O. U.; Diget, Christian Aa.; Bergmann, Uffe C.; Borge, Maria J. G.; Cederkäll, Joakim; Dendooven, Peter; Fraile, Luis M.; Franchoo, Serge; Fedosseev, Valentin N.; Fulton, Brian R.; Huang, Wenxue; Huikari, Jussi; Jeppesen, Henrik B.; Jokinen, Ari S.; Jones, Peter; Jonson, Björn; Köster, Ulli; Langanke, Karlheinz; Meister, Mikael; Nilsson, Thomas; Nyman, Göran; Prezado, Yolanda; Riisager, Karsten; Rinta-Antila, Sami; Tengblad, Olof; Turrion, Manuela; Wang, Youbao; Weissman, Leonid; Wilhelmsen, Katarina; Äystö, Juha; ISOLDE Collaboration

    2005-01-01

    In the centres of stars where the temperature is high enough, three α-particles (helium nuclei) are able to combine to form 12C because of a resonant reaction leading to a nuclear excited state. (Stars with masses greater than ~0.5 times that of the Sun will at some point in their lives have a central temperature high enough for this reaction to proceed.) Although the reaction rate is of critical significance for determining elemental abundances in the Universe, and for determining the size of the iron core of a star just before it goes supernova, it has hitherto been insufficiently determined. Here we report a measurement of the inverse process, where a 12C nucleus decays to three α-particles. We find a dominant resonance at an energy of ~11MeV, but do not confirm the presence of a resonance at 9.1MeV (ref. 3). We show that interference between two resonances has important effects on our measured spectrum. Using these data, we calculate the triple-α rate for temperatures from 107K to 1010K and find significant deviations from the standard rates. Our rate below ~5 × 107K is higher than the previous standard, implying that the critical amounts of carbon that catalysed hydrogen burning in the first stars are produced twice as fast as previously believed. At temperatures above 109K, our rate is much less, which modifies predicted nucleosynthesis in supernovae.

  16. The state of benzene in TIP slurry using nuclear magnetic resonance measurements

    SciTech Connect

    Dworjanyn, L.O.

    1997-11-14

    Nuclear Magnetic Resonance (NMR) measurements on In-Tank Precipitation (ITP) simulated potassium tetraphenylborate (KTPB) slurries at Pacific Northwest National Laboratory have been completed. Most measurements were made on 4 wt percent KTPB slurry in 4 to 5 molar sodium salt solution. Liquid benzene was added volumetrically to the slurry in 25-mL vials and agitated to create a suspension. Earlier tests using dyed benzene showed that benzene remains suspended permanently in the slurry and the only visible change is overall slurry settling. Gentle vial agitation restores the original suspension state. To simulate in-situ uniformly dispersed benzene, benzene/KTPB samples were homogenized using a high speed rotor/stator biological homogenizer. Photomicrographs using homogenized samples containing dyed benzene showed no residual benzene droplets and fairly uniform coloration of the KTPB solids structure. All benzene concentration estimates are based on benzene addition since there is no available analytical method for benzene in slurry. Benzene losses could be significant, particularly at low concentrations and during homogenization.

  17. The aftermath of the Fukushima nuclear accident: Measures to contain groundwater contamination.

    PubMed

    Gallardo, Adrian H; Marui, Atsunao

    2016-03-15

    Several measures are being implemented to control groundwater contamination at the Fukushima Daiichi Nuclear Plant. This paper presents an overview of work undertaken to contain the spread of radionuclides, and to mitigate releases to the ocean via hydrological pathways. As a first response, contaminated water is being held in tanks while awaiting treatment. Limited storage capacity and the risk of leakage make the measure unsustainable in the long term. Thus, an impervious barrier has been combined with a drain system to minimize the discharge of groundwater offshore. Caesium in seawater at the plant port has largely dropped, although some elevated concentrations are occasionally recorded. Moreover, a dissimilar decline of the radioactivity in fish could indicate additional sources of radionuclides intake. An underground frozen shield is also being constructed around the reactors. This structure would reduce inflows to the reactors and limit the interaction between fresh and contaminated waters. Additional strategies include groundwater abstraction and paving of surfaces to lower water levels and further restrict the mobilisation of radionuclides. Technical difficulties and public distrust pose an unprecedented challenge to the site remediation. Nevertheless, the knowledge acquired during the initial work offers opportunities for better planning and more rigorous decisions in the future.

  18. High-pressure autoclave for multipurpose nuclear magnetic resonance measurements up to 10 MPa

    NASA Astrophysics Data System (ADS)

    Behr, W.; Haase, A.; Reichenauer, G.; Fricke, J.

    1999-05-01

    High-pressure nuclear magnetic resonance (NMR) is an established method in NMR spectroscopy: on-line coupling of high-performance liquid chromatography with NMR, for example, reveals structural information which cannot be obtained with any other method. However, applications has been focused solely on high-pressure NMR spectroscopy, even though high-pressure NMR imaging allows in situ studies of processes such as the fluid exchange in porous media. A versatile high-pressure autoclave for NMR imaging is described in this article. The autoclave allows measurements in any horizontal NMR imager using magnetic field coil systems with an inside diameter of more than 70 mm. Any sample with a diameter up to 28 mm and a length of about 200 mm can be investigated. The autoclave is constructed for operating pressures up to 10 MPa and is temperature controlled between 10 and 60 °C. The materials of the high-pressure cell which are the thermoplastic polyetheretherketon (PEEK) for the pressure tube and brass (63% Cu, 37% Zn) for the caps also permit investigations with aggressive fluids such as supercritical carbon dioxide. Inlet and outlet valves allow replacement of fluids and pressure variations in the autoclave during the NMR measurement. FLASH NMR images of the fluid exchange of methanol for liquid carbon dioxide in silica alcogels at 6.5 MPa are presented in order to demonstrate possible applications.

  19. Measurements for spin inversion and noninversion in successive decays via nuclear magnetic resonance on oriented nuclei

    SciTech Connect

    Ohya, S.; Ohtsubo, T.; Komatsuzaki, K.; Cho, D.J.; Muto, S.

    1996-09-01

    Nuclear magnetic resonance on oriented nuclei (NMR-ON) measurements were performed on the successive decays of {sup 89}Zr-{sup 89}Y{sup {ital m}} and {sup 191}Os-{sup 191}Ir{sup {ital m}} in Fe. The NMR-ON spectra of {sup 89}Zr{ital Fe} and {sup 191}Os{ital Fe} were obtained by detecting {gamma} rays from the decay of the isomers, {sup 89}Y{sup m} and {sup 191}Ir{sup m}, respectively. For {sup 89}Zr{ital Fe}, the anisotropy of the {gamma} ray increased at the resonance. On the other hand, for {sup 191}Os{ital Fe} the anisotropy of the {gamma} ray decreased at the resonance. These phenomena were explained using the spin inversion and spin noninversion processes including the lifetimes of the isomers and spin lattice relaxation times. NMR-ON measurements for such spin inversion and noninversion processes were reported. The resonance spectra were also observed by detecting {beta} rays from {sup 89}Zr and {sup 191}Os. In these experiments the magnetic moments of {sup 89}Zr and {sup 191}Os were determined to be {minus}1.08 (2) {mu}{sub N} and 0.962 (28) {mu}{sub N}, respectively. The signs of the magnetic moments of {sup 89}Y{sup m} and {sup 191}Ir{sup m} were also determined to be positive. {copyright} {ital 1996 The American Physical Society.}

  20. Method for Non-Intrusively Identifying a Contained Material Utilizing Uncollided Nuclear Transmission Measurements

    SciTech Connect

    Morrison, John L.; Stephens, Alan G.; Grover Blaine S.

    1999-02-26

    An improved nuclear diagnostic method identifies a contained target material by measuring on-axis, mono-energetic uncollided particle radiation transmitted through a target material for two penetrating radiation beam energies, and applying specially developed algorithms to estimate a ratio of macroscopic neutron cross-sections for the uncollided particle radiation at the two energies, where the penetrating radiation is a neutron beam, or a ratio of linear attenuation coefficients for the uncollided particle radiation at the two energies, where the penetrating radiation is a gamma-ray beam. Alternatively, the measurements are used to derive a minimization formula based on the macroscopic neutron cross-sections for the uncollided particle radiation at the two neutron beam energies, or the linear attenuation coefficients for the uncollided particle radiation at the two gamma-ray beam energies. A candidate target material database, including known macroscopic neutron cross-sections or linear attenuation coefficients for target materials at the selected neutron or gamma-ray beam energies, is used to approximate the estimated ratio or to solve the minimization formula, such that the identity of the contained target material is discovered.

  1. Time-of-Flight Mass Measurements for Nuclear Processes in Neutron Star Crusts

    NASA Astrophysics Data System (ADS)

    Estradé, A.; Matoš, M.; Schatz, H.; Amthor, A. M.; Bazin, D.; Beard, M.; Becerril, A.; Brown, E. F.; Cyburt, R.; Elliot, T.; Gade, A.; Galaviz, D.; George, S.; Gupta, S. S.; Hix, W. R.; Lau, R.; Lorusso, G.; Möller, P.; Pereira, J.; Portillo, M.; Rogers, A. M.; Shapira, D.; Smith, E.; Stolz, A.; Wallace, M.; Wiescher, M.

    2011-10-01

    We present results from time-of-flight nuclear mass measurements at the National Superconducting Cyclotron Laboratory that are relevant for neutron star crust models. The masses of 16 neutron-rich nuclei in the scandium-nickel range were determined simultaneously, with the masses of V61, Cr63, Mn66, and Ni74 measured for the first time with mass excesses of -30.510(890)MeV, -35.280(650)MeV, -36.900(790)MeV, and -49.210(990)MeV, respectively. With these results the locations of the dominant electron capture heat sources in the outer crust of accreting neutron stars that exhibit super bursts are now experimentally constrained. We find the experimental Q value for the Fe66→Mn66 electron capture to be 2.1 MeV (2.6σ) smaller than predicted, resulting in the transition occurring significantly closer to the neutron star surface.

  2. Ion Beam Measurements of a Dense Plasma Focus Device Using CR 39 Nuclear Track Detectors

    NASA Astrophysics Data System (ADS)

    Ngoi, S. K.; Yap, S. L.; Wong, C. S.; Saadah, A. R.

    2008-05-01

    The project is carried out using a small Mather type plasma focus device powered by a 15 kV, 30 μF capacitor. The filling gas used is argon. The ion beam generated is investigated by both time resolved and time integrated methods. Investigation on the dynamic of the current sheath is also carried out in order to obtain an optimum condition for ion beam production. The angular distribution of the ion emission is measured at positions of 0° (end-on), 45° and 90° (side-on) by using CR-39 nuclear track detectors. The divergence of the ion beam is also determined using these detectors. A biased ion collector is used for time resolved measurement of the ion beam. Time of flight technique is employed for the determination of the ion beam energy. Average ion beam energy obtained is about 180 keV. The ion beam produced can be used for applications such as material surface modification and ion implantation.

  3. Time-of-flight mass measurements for nuclear processes in neutron star crusts.

    PubMed

    Estradé, A; Matoš, M; Schatz, H; Amthor, A M; Bazin, D; Beard, M; Becerril, A; Brown, E F; Cyburt, R; Elliot, T; Gade, A; Galaviz, D; George, S; Gupta, S S; Hix, W R; Lau, R; Lorusso, G; Möller, P; Pereira, J; Portillo, M; Rogers, A M; Shapira, D; Smith, E; Stolz, A; Wallace, M; Wiescher, M

    2011-10-21

    We present results from time-of-flight nuclear mass measurements at the National Superconducting Cyclotron Laboratory that are relevant for neutron star crust models. The masses of 16 neutron-rich nuclei in the scandium-nickel range were determined simultaneously, with the masses of (61)V, (63)Cr, (66)Mn, and (74)Ni measured for the first time with mass excesses of -30.510(890) MeV, -35.280(650) MeV, -36.900(790) MeV, and -49.210(990) MeV, respectively. With these results the locations of the dominant electron capture heat sources in the outer crust of accreting neutron stars that exhibit super bursts are now experimentally constrained. We find the experimental Q value for the (66)Fe→(66)Mn electron capture to be 2.1 MeV (2.6σ) smaller than predicted, resulting in the transition occurring significantly closer to the neutron star surface. © 2011 American Physical Society

  4. Correlated Biofilm Imaging, Transport and Metabolism Measurements via Combined Nuclear Magnetic Resonance and Confocal Microscopy

    SciTech Connect

    Mclean, Jeffrey S.; Ona, Ositadinma; Majors, Paul D.

    2008-02-18

    Bacterial biofilms are complex, three-dimensional, communities that are found nearly everywhere in nature1 and are being recognized as the cause of treatment-resistant infections1 2. Advanced methods are required to characterize their collective and spatial patterns of metabolism however most techniques are invasive or destructive. Here we describe the use of a combined confocal laser scanning microscopy (CLSM) and nuclear magnetic resonance (NMR) microscopy system to monitor structure, mass transport, and metabolism in active biofilms. Non-invasive NMR methods provide macroscopic structure along with spatially-resolved metabolite profiles and diffusion measurements. CLSM enables monitoring of cells by fluorescent protein reporters to investigate biofilm structure and gene expression concurrently. A planar sample chamber design facilitates depth-resolved measurements on 140 nL sample volumes under laminar flow conditions. The techniques and approaches described here are applicable to environmental and medically relevant microbial communities, thus providing key metabolic information for promoting beneficial biofilms and treating associated diseases.

  5. 7Li relaxation time measurements at very low magnetic field by 1H dynamic nuclear polarization

    NASA Astrophysics Data System (ADS)

    Zeghib, Nadir; Grucker, Daniel

    2001-09-01

    Dynamic nuclear polarization (DNP) of water protons was used to measure the relaxation time of lithium at very low magnetic field as a demonstration of the use of DNP for nuclei less abundant than water protons. Lithium (Li+) was chosen because it is an efficient treatment for manic-depressive illness, with an unknown action mechanism. After having recalled the theoretical basis of a three-spin system comprising two nuclei - the water proton of the solvent, the dissolved Li+ ion and the free electron of a free radical - we have developed a transient solution in order to optimize potential biological applications of Li DNP. The three-spin model has allowed computation of all the parameters of the system - the longitudinal relaxation rate per unit of free radical concentration, the dipolar and scalar part of the coupling between the nuclei and the electron, and the maximum signal enhancement achievable for both proton and lithium spins. All these measurements have been obtained solely through the detection of the proton resonance.

  6. Method for non-intrusively identifying a contained material utilizing uncollided nuclear transmission measurements

    DOEpatents

    Morrison, John L.; Stephens, Alan G.; Grover, S. Blaine

    2001-11-20

    An improved nuclear diagnostic method identifies a contained target material by measuring on-axis, mono-energetic uncollided particle radiation transmitted through a target material for two penetrating radiation beam energies, and applying specially developed algorithms to estimate a ratio of macroscopic neutron cross-sections for the uncollided particle radiation at the two energies, where the penetrating radiation is a neutron beam, or a ratio of linear attenuation coefficients for the uncollided particle radiation at the two energies, where the penetrating radiation is a gamma-ray beam. Alternatively, the measurements are used to derive a minimization formula based on the macroscopic neutron cross-sections for the uncollided particle radiation at the two neutron beam energies, or the linear attenuation coefficients for the uncollided particle radiation at the two gamma-ray beam energies. A candidate target material database, including known macroscopic neutron cross-sections or linear attenuation coefficients for target materials at the selected neutron or gamma-ray beam energies, is used to approximate the estimated ratio or to solve the minimization formula, such that the identity of the contained target material is discovered.

  7. Compendium of the Environmental Measurements Laboratory's research projects related to the Chernobyl nuclear accident

    SciTech Connect

    Volchok, H L; Chieco, N

    1986-10-01

    Following the accident at the Chernobyl nuclear reactor power station in the USSR on April 26, 1986, the Environmental Measurements Laboratory (EML) initiated a number of research projects as follows: (1) selected sites in both the Deposition and Surface Air networks were alerted and their sampling protocols adjusted to accommodate the anticipated arrival times and activity concentrations of the Chernobyl debris; (2) a number of cooperative programs involving field work, sampling, analysis and data interpretation were set up with institutions and scientists in other countries; (3) EML's Regional Baseline Station at Chester, NJ, as well as the roof of the Laboratory in New York City, provided bases for sampling and measurements to study the radionuclide concentrations, radiation levels, physical characteristics and potential biological implications of the Chernobyl fallout on the northeastern United States; and (4) the resulting fallout from the Chernobyl accident provided an 'experiment of opportunity' in that it enabled us to study fresh fission product deposition using collection systems resurrected from the 1950's and 1960's for comparison with current state-of-the-art methodology. The 13 reports of this volume have been entered separately into the data base.

  8. Establishing protective long term measures after severe nuclear accidents using multiple criteria

    SciTech Connect

    Papazoglou, I.A.; Kollas, J.G.

    1997-05-01

    This paper proposes a methodology supporting decisions on protective measures following severe nuclear accidents and demonstrates its use. A multicriteria decision analysis approach is adopted where value tradeoffs are postponed until the very last stage of the decision process. All feasible solutions are implicitly considered and evaluated in the chosen criteria. Technically inferior solutions are excluded. Only the non-dominated or efficient solutions forming the {open_quotes}efficient frontier{close_quotes} are retained and presented to the decision makers. Implementation of inefficient solutions is in this way avoided. A choice among the efficient solutions, although it implies value tradeoffs among the multiple criteria, avoids the direct and apriori assessment of preferences. An interactive computer package has been developed with which the decision maker can choose a point on the efficient frontier in the consequence space and immediately see the corresponding alternative in the decision space. The methodology is demonstrated through an application on the choice among possible protective measures in contaminated areas of the former USSR after the Chernobyl accident using as criteria the collective effective life-time dose received by the population and the cost associated with each possible decision. 11 refs., 9 figs., 8 tabs.

  9. Correlated biofilm imaging, transport and metabolism measurements via combined nuclear magnetic resonance and confocal microscopy

    PubMed Central

    McLean, Jeffrey S; Ona, Ositadinma N; Majors, Paul D

    2015-01-01

    Bacterial biofilms are complex, three-dimensional communities found nearly everywhere in nature and are also associated with many human diseases. Detailed metabolic information is critical to understand and exploit beneficial biofilms as well as combat antibiotic-resistant, disease-associated forms. However, most current techniques used to measure temporal and spatial metabolite profiles in these delicate structures are invasive or destructive. Here, we describe imaging, transport and metabolite measurement methods and their correlation for live, non-invasive monitoring of biofilm processes. This novel combination of measurements is enabled by the use of an integrated nuclear magnetic resonance (NMR) and confocal laser scanning microscope (CLSM). NMR methods provide macroscopic structure, metabolic pathway and rate data, spatially resolved metabolite concentrations and water diffusion profiles within the biofilm. In particular, current depth-resolved spectroscopy methods are applied to detect metabolites in 140–190 nl volumes within biofilms of the dissimilatory metal-reducing bacterium Shewanella oneidensis strain MR-1 and the oral bacterium implicated in caries disease, Streptococcus mutans strain UA159. The perfused sample chamber also contains a transparent optical window allowing for the collection of complementary fluorescence information using a unique, in-magnet CLSM. In this example, the entire three-dimensional biofilm structure was imaged using magnetic resonance imaging. This was then correlated to a fluorescent CLSM image by employing a green fluorescent protein reporter construct of S. oneidensis. Non-invasive techniques such as described here, which enable measurements of dynamic metabolic processes, especially in a depth-resolved fashion, are expected to advance our understanding of processes occurring within biofilm communities. PMID:18253132

  10. New neutron cross-section measurements on {sup 19}F, {sup 39,41}K, {sup 55}Mn, and {sup 103}Rh for improved nuclear criticality safety

    SciTech Connect

    Guber, K. H.; Leal, L. C.; Sayer, R. O.; Koehler, P. E.; Wiarda, D.; Valentine, T. E.; Derrien, H.; Harvey, J. A.; Kopecky, S.; Siegler, P.; Schillebeeckx, P.; Wynants, R.; Ivanov, I.; Borella, A.

    2006-07-01

    A series of new measurements has been undertaken in response to deficiencies identified in nuclear data libraries of crucial importance to the Nuclear Criticality Safety Program as well as for burnup credit studies involving the transportation of spent nuclear fuel. New data and evaluations including covariances are required for several stable fission products as well as for materials found in mixtures with uranium. (authors)

  11. Measurement of soil carbon oxidation state and oxidative ratio by 13C nuclear magnetic resonance

    USGS Publications Warehouse

    Hockaday, W.C.; Masiello, C.A.; Randerson, J.T.; Smernik, R.J.; Baldock, J.A.; Chadwick, O.A.; Harden, J.W.

    2009-01-01

    The oxidative ratio (OR) of the net ecosystem carbon balance is the ratio of net O2 and CO2 fluxes resulting from photosynthesis, respiration, decomposition, and other lateral and vertical carbon flows. The OR of the terrestrial biosphere must be well characterized to accurately estimate the terrestrial CO2 sink using atmospheric measurements of changing O2 and CO2 levels. To estimate the OR of the terrestrial biosphere, measurements are needed of changes in the OR of aboveground and belowground carbon pools associated with decadal timescale disturbances (e.g., land use change and fire). The OR of aboveground pools can be measured using conventional approaches including elemental analysis. However, measuring the OR of soil carbon pools is technically challenging, and few soil OR data are available. In this paper we test three solid-state nuclear magnetic resonance (NMR) techniques for measuring soil OR, all based on measurements of the closely related parameter, organic carbon oxidation state (Cox). Two of the three techniques make use of a molecular mixing model which converts NMR spectra into concentrations of a standard suite of biological molecules of known C ox. The third technique assigns Cox values to each peak in the NMR spectrum. We assess error associated with each technique using pure chemical compounds and plant biomass standards whose Cox and OR values can be directly measured by elemental analyses. The most accurate technique, direct polarization solid-state 13C NMR with the molecular mixing model, agrees with elemental analyses to ??0.036 Cox units (??0.009 OR units). Using this technique, we show a large natural variability in soil Cox and OR values. Soil Cox values have a mean of -0.26 and a range from -0.45 to 0.30, corresponding to OR values of 1.08 ?? 0.06 and a range from 0.96 to 1.22. We also estimate the OR of the carbon flux from a boreal forest fire. Analysis of soils from nearby intact soil profiles imply that soil carbon losses associated

  12. Nuclear magnetic resonance relaxation and diffusion measurements as a proxy for soil properties

    NASA Astrophysics Data System (ADS)

    Duschl, Markus; Pohlmeier, Andreas; Galvosas, Petrik; Vereecken, Harry

    2013-04-01

    Nuclear Magnetic Resonance (NMR) relaxation and NMR diffusion measurements are two of a series of fast and non-invasive NMR applications widely used e.g. as well logging tools in petroleum exploration [1]. For experiments with water, NMR relaxation measures the relaxation behaviour of former excited water molecules, and NMR diffusion evaluates the self-diffusion of water. Applied in porous media, both relaxation and diffusion measurements depend on intrinsic properties of the media like pore size distribution, connectivity and tortuosity of the pores, and water saturation [2, 3]. Thus, NMR can be used to characterise the pore space of porous media not only in consolidated sediments but also in soil. The physical principle behind is the relaxation of water molecules in an external magnetic field after excitation. In porous media water molecules in a surface layer of the pores relax faster than the molecules in bulk water because of interactions with the pore wall. Thus, the relaxation in smaller pores is generally faster than in bigger pores resulting in a relaxation time distribution for porous media with a range of pore sizes like soil [4]. In NMR diffusion experiments, there is an additional encoding of water molecules by application of a magnetic field gradient. Subsequent storage of the magnetization and decoding enables the determination of the mean square displacement and therefore of the self-diffusion of the water molecules [5]. Employing various relaxation and diffusion experiments, we get a measure of the surface to volume ratio of the pores and the tortuosity of the media. In this work, we show the characterisation of a set of sand and soil samples covering a wide range of textural classes by NMR methods. Relaxation times were monitored by the Carr-Purcell-Meiboom-Gill sequence and analysed using inverse Laplace transformation. Apparent self-diffusion constants were detected by a 13-intervall pulse sequence and variation of the storage time. We

  13. 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.

  14. Measurement and Analysis of Gamma-Rays Emitted From Spent Nuclear Fuel Above 3 MeV

    SciTech Connect

    Rodriguez, Douglas C.; Anderson, Elaina R.; Anderson, Kevin K.; Campbell, Luke W.; Fast, James E.; Jarman, Kenneth D.; Kulisek, Jonathan A.; Orton, Christopher R.; Runkle, Robert C.; Stave, Sean C.

    2013-12-01

    The gamma-ray spectrum of spent nuclear fuel in the 3- to 6-MeV energy range is important for active interrogation since emitted gamma rays emitted from nuclear decay are not expected to interfere with measurements in this energy region. There is, unfortunately, a dearth of empirical measurements from spent nuclear fuel in this region. This work is an initial attempt to partially ll this gap by presenting an analysis of gamma-ray spectra collected from a set of spent nuclear fuel sources using a high-purity germanium detector array. This multi-crystal array possesses a large collection volume, providing high energy resolution up to 16 MeV. The results of these measurements establish the continuum count-rate in the energy region between 3- and 6-MeV. Also assessed is the potential for peaks from passive emissions to interfere with peak measurements resulting from active interrogation delayed emissions. As one of the first documented empirical measurements of passive emissions from spent fuel for energies above 3 MeV, this work provides a foundation for active interrogation model validation and detector development.

  15. Measurement of the ionization yield of nuclear recoils in liquid argon using a two-phase detector with electroluminescence gap

    NASA Astrophysics Data System (ADS)

    Bondar, A.; Buzulutskov, A.; Dolgov, A.; Grishnyaev, E.; Nosov, V.; Oleynikov, V.; Polosatkin, S.; Shekhtman, L.; Shemyakina, E.; Sokolov, A.

    2017-05-01

    A measurement of ionization yields in noble-gas liquids is relevant to the energy calibration of nuclear recoil detectors for dark matter search and coherent neutrino-nucleus scattering experiments. In this work we further study the ionization yield of nuclear recoils in liquid Ar, using a two-phase detector with an electroluminescence gap and DD neutron generator. The ionization yields of nuclear recoils in liquid Ar were measured at 233 keV and electric fields of 0.56 and 0.62 kV/cm; their values amounted to 5.9 ± 0.8 and 7.4 ± 1 e-/keV, respectively. The characteristic dependences of the ionization yield on energy and electric field were determined, while comparing the results obtained to those at lower energies and higher fields.

  16. Solution of resource allocation problem for identification of cost-effective measures to reduce nuclear proliferation risks

    SciTech Connect

    Andrianov, A.; Kuptsov, I.

    2013-07-01

    This report presents a methodology of selection of cost-effective measures to reduce nuclear proliferation risks. The methodology relies on a graded security model used in practice in different applications. The method is based on the controlled finite Markov chain approach set in combination with discrete dynamic programming and MCDM (Multi Criteria Decision Making) techniques that enables the expert to select the cost-effective measures to reduce nuclear proliferation risks depending on availability of resources. The analysis performed with different number of possible measures confirms the conclusions that the implementation of extra-large costs may not produce the required effect, and the increase in resources above a certain level does not appear sensitive. Diversification in improving the effectiveness of other measures seems more rational and efficient for the whole system than the unlimited improvement of the effectiveness of only one measure.

  17. 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.

  18. Analysis of Influence Factors on Nuclear magnetic Resonance Measurement and Correction Method in Igneous Rocks

    NASA Astrophysics Data System (ADS)

    Tan, M.

    2016-12-01

    Nuclear magnetic resonance (NMR) logging has significant advantages in reservoir identification, fluid typing, and calculation of porosity and permeability in sedimentary rocks. However, NMR well logging porosity was badly underestimated, which limited the application of NMR logging technology. Therefore, it is necessary to analyze the influence factors on NMR measurement and study the correction method and logging interpretation model in igneous rocks. Based on the characteristics of igneous rocks, influence factors are investigated from two aspects of NMR experimental and theoretical perspective. The laboratory analysis indicates that the relative error between NMR porosity and core porosity generally increases from acid tuff and rhyolite, intermediate andesite and granite-porphyry, and falic basalt. Moreover, NMR porosity relative error increases with paramagnetic substance such as iron, manganese and nickel concentrations increasing. Theoretically, NMR relaxation mechanism indicates that the magnetic susceptibility leads to additional internal magnetic field gradient, which makes T2relaxation distribution shift forward and the porosity relative error also generally increases with the magnetic susceptibility rising. Therefore, the paramagnetic substance and high magnetic susceptibility lead to the NMR porosity underestimation. How to correct the NMR measurement in igneous rocks is another key problem. In view of the above analysis, the empirical formula of NMR porosity correction was built based on paramagnetic element content by using multiple regression. Moreover, we considered the influences of diffusion relaxation and improved the inversion algorithm, and the T2distribution was subsequently corrected. The simulation experiment proves the correction method effective. In case study, NMR logging data was reprocessed by this new method, and the NMR porosity and permeability match well with core laboratory measurements, and the corrected T2 distributions shift

  19. 137Cesium exposure and spirometry measures in Ukrainian children affected by the Chernobyl nuclear incident.

    PubMed

    Svendsen, Erik R; Kolpakov, Igor E; Stepanova, Yevgenia I; Vdovenko, Vitaliy Y; Naboka, Maryna V; Mousseau, Timothy A; Mohr, Lawrence C; Hoel, David G; Karmaus, Wilfried J J

    2010-05-01

    After the Chernobyl accident in 1986, children of the contaminated Narodichesky region of Ukraine were obliged to participate in a yearly medical screening. They have been exposed to 137cesium (137Cs; half-life = 30 years) in contaminated soils, air, and food. Using a "natural experiment" approach and a longitudinal prospective cohort study design, we investigated the association of soil 137Cs and spirometry measures for 415 children using 1,888 repeated measurements from 1993 to 1998. Mean baseline village soil 137Cs measurements, which varied from 29.0 to 879 kBq/m2, were used as exposure indicators. A standardized spirometry protocol and prediction equations specific to Ukrainian children were used by the same pulmonologist in all screenings. Children living in villages with the highest quintile of soil 137Cs were 2.60 times more likely to have forced vital capacity (FVC) < 80% of predicted [95% confidence interval (CI), 1.07-6.34] and 5.08 times more likely to have a ratio of forced expiratory volume in 1 sec (FEV1) to FVC% < 80% (95% CI, 1.02-25.19). We found statistically significant evidence of both airway obstruction (FEV1/FVC%, peak expiratory flow, and maximum expiratory flow at 25%, 50%, and 75% of FVC) and restriction (FVC) with increasing soil 137Cs. These findings are unique and suggest significant airway obstruction and restriction consequences for children chronically exposed to low-dose radioactive contaminants such as those found downwind of the Chernobyl Nuclear Power Plant.

  20. 137Cesium Exposure and Spirometry Measures in Ukrainian Children Affected by the Chernobyl Nuclear Incident

    PubMed Central

    Svendsen, Erik R.; Kolpakov, Igor E.; Stepanova, Yevgenia I.; Vdovenko, Vitaliy Y.; Naboka, Maryna V.; Mousseau, Timothy A.; Mohr, Lawrence C.; Hoel, David G.; Karmaus, Wilfried J.J.

    2010-01-01

    Background After the Chernobyl accident in 1986, children of the contaminated Narodichesky region of Ukraine were obliged to participate in a yearly medical screening. They have been exposed to 137cesium (137Cs; half-life = 30 years) in contaminated soils, air, and food. Objective Using a “natural experiment” approach and a longitudinal prospective cohort study design, we investigated the association of soil 137Cs and spirometry measures for 415 children using 1,888 repeated measurements from 1993 to 1998. Methods Mean baseline village soil 137Cs measurements, which varied from 29.0 to 879 kBq/m2, were used as exposure indicators. A standardized spirometry protocol and prediction equations specific to Ukrainian children were used by the same pulmonologist in all screenings. Results Children living in villages with the highest quintile of soil 137Cs were 2.60 times more likely to have forced vital capacity (FVC) < 80% of predicted [95% confidence interval (CI), 1.07–6.34] and 5.08 times more likely to have a ratio of forced expiratory volume in 1 sec (FEV1) to FVC% < 80% (95% CI, 1.02–25.19). We found statistically significant evidence of both airway obstruction (FEV1/FVC%, peak expiratory flow, and maximum expiratory flow at 25%, 50%, and 75% of FVC) and restriction (FVC) with increasing soil 137Cs. Conclusions These findings are unique and suggest significant airway obstruction and restriction consequences for children chronically exposed to low-dose radioactive contaminants such as those found downwind of the Chernobyl Nuclear Power Plant. PMID:20100677

  1. Robust determination of surface relaxivity from nuclear magnetic resonance DT(2) measurements.

    PubMed

    Luo, Zhi-Xiang; Paulsen, Jeffrey; Song, Yi-Qiao

    2015-10-01

    Nuclear magnetic resonance (NMR) is a powerful tool to probe into geological materials such as hydrocarbon reservoir rocks and groundwater aquifers. It is unique in its ability to obtain in situ the fluid type and the pore size distributions (PSD). The T1 and T2 relaxation times are closely related to the pore geometry through the parameter called surface relaxivity. This parameter is critical for converting the relaxation time distribution into the PSD and so is key to accurately predicting permeability. The conventional way to determine the surface relaxivity ρ2 had required independent laboratory measurements of the pore size. Recently Zielinski et al. proposed a restricted diffusion model to extract the surface relaxivity from the NMR diffusion-T2 relaxation (DT2) measurement. Although this method significantly improved the ability to directly extract surface relaxivity from a pure NMR measurement, there are inconsistencies with their model and it relies on a number of preset parameters. Here we propose an improved signal model to incorporate a scalable LT and extend their method to extract the surface relaxivity based on analyzing multiple DT2 maps with varied diffusion observation time. With multiple diffusion observation times, the apparent diffusion coefficient correctly describes the restricted diffusion behavior in samples with wide PSDs, and the new method does not require predetermined parameters, such as the bulk diffusion coefficient and tortuosity. Laboratory experiments on glass beads packs with the beads diameter ranging from 50 μm to 500 μm are used to validate the new method. The extracted diffusion parameters are consistent with their known values and the determined surface relaxivity ρ2 agrees with the expected value within ±7%. This method is further successfully applied on a Berea sandstone core and yields surface relaxivity ρ2 consistent with the literature. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Measurement of (131)I activity in thyroid of nuclear medical staff and internal dose assessment in a Polish nuclear medical hospital.

    PubMed

    Brudecki, K; Kowalska, A; Zagrodzki, P; Szczodry, A; Mroz, T; Janowski, P; Mietelski, J W

    2017-03-01

    This paper presents results of (131)I thyroid activity measurements in 30 members of the nuclear medicine personnel of the Department of Endocrinology and Nuclear Medicine Holy Cross Cancer Centre in Kielce, Poland. A whole-body spectrometer equipped with two semiconductor gamma radiation detectors served as the basic research instrument. In ten out of 30 examined staff members, the determined (131)I activity was found to be above the detection limit (DL = 5 Bq of (131)I in the thyroid). The measured activities ranged from (5 ± 2) Bq to (217 ± 56) Bq. The highest activities in thyroids were detected for technical and cleaning personnel, whereas the lowest values were recorded for medical doctors. Having measured the activities, an attempt has been made to estimate the corresponding annual effective doses, which were found to range from 0.02 to 0.8 mSv. The highest annual equivalent doses have been found for thyroid, ranging from 0.4 to 15.4 mSv, detected for a cleaner and a technician, respectively. The maximum estimated effective dose corresponds to 32% of the annual background dose in Poland, and to circa 4% of the annual limit for the effective dose due to occupational exposure of 20 mSv per year, which is in compliance with the value recommended by the International Commission on Radiological Protection.

  3. Controlling the object phase for g-factor reduction in phase-Constrained parallel MRI using spatially selective RF pulses.

    PubMed

    Kettinger, Adam O; Kannengiesser, Stephan A R; Breuer, Felix A; Vidnyanszky, Zoltan; Blaimer, Martin

    2017-09-01

    Parallel imaging generally entails a reduction in the signal-to-noise ratio of the final image. Phase-constrained methods aim to improve reconstruction quality by using symmetry properties of k-space. Noise amplification in phase-constrained reconstruction depends heavily on the object background phase. The purpose of this work is to present a new approach of using tailored radiofrequency pulses to optimize the object phase distribution in order to maximize the benefit of phase-constrained reconstruction, and to minimize the noise amplification. Intrinsic object phase and coil sensitivity profiles are measured in a prescan. Optimal phase distribution is computed to maximize signal-to-noise ratio in the given setup. Tailored radiofrequency pulses are designed to introduce the optimal phase map in the following accelerated acquisitions, subsequently reconstructed by phase-constrained methods. The potential of the method is demonstrated in vivo with in-plane accelerated (8x) and simultaneous multislice (3x) acquisitions. Mean g-factors are reduced by up to a factor of 2 compared with conventional techniques when an appropriate phase-constrained reconstruction is applied to phase-optimized acquisitions, enhancing the signal-to-noise ratio of the final images and the visibility of small details. Combining phase-constrained reconstruction and phase optimization by tailored radiofrequency pulses can provide notable improvement in the signal-to-noise ratio and reconstruction quality of accelerated MRI. Magn Reson Med, 2017. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  4. Measurement of Nuclear Recoils in the CDMS II Dark Matter Search

    SciTech Connect

    Fallows, Scott Mathew

    2014-12-01

    The Cryogenic Dark Matter Search (CDMS) experiment is designed to directly detect elastic scatters of weakly-interacting massive dark matter particles (WIMPs), on target nuclei in semiconductor crystals composed of Si and Ge. These scatters would occur very rarely, in an overwhelming background composed primarily of electron recoils from photons and electrons, as well as a smaller but non-negligible background of WIMP-like nuclear recoils from neutrons. The CDMS II generation of detectors simultaneously measure ionization and athermal phonon signals from each scatter, allowing discrimination against virtually all electron recoils in the detector bulk. Pulse-shape timing analysis allows discrimination against nearly all remaining electron recoils taking place near detector surfaces. Along with carefully limited neutron backgrounds, this experimental program allowed for \\background- free" operation of CDMS II at Soudan, with less than one background event expected in each WIMP-search analysis. As a result, exclusionary upper-limits on WIMP-nucleon interaction cross section were placed over a wide range of candidate WIMP masses, ruling out large new regions of parameter space.

  5. Symmetry based frequency domain processing to remove harmonic noise from surface nuclear magnetic resonance measurements

    NASA Astrophysics Data System (ADS)

    Hein, Annette; Larsen, Jakob Juul; Parsekian, Andrew D.

    2017-02-01

    Surface nuclear magnetic resonance (NMR) is a unique geophysical method due to its direct sensitivity to water. A key limitation to overcome is the difficulty of making surface NMR measurements in environments with anthropogenic electromagnetic noise, particularly constant frequency sources such as powerlines. Here we present a method of removing harmonic noise by utilizing frequency domain symmetry of surface NMR signals to reconstruct portions of the spectrum corrupted by frequency-domain noise peaks. This method supplements the existing NMR processing workflow and is applicable after despiking, coherent noise cancellation, and stacking. The symmetry based correction is simple, grounded in mathematical theory describing NMR signals, does not introduce errors into the data set, and requires no prior knowledge about the harmonics. Modelling and field examples show that symmetry based noise removal reduces the effects of harmonics. In one modelling example, symmetry based noise removal improved signal-to-noise ratio in the data by 10 per cent. This improvement had noticeable effects on inversion parameters including water content and the decay constant T2*. Within water content profiles, aquifer boundaries and water content are more accurate after harmonics are removed. Fewer spurious water content spikes appear within aquifers, which is especially useful for resolving multilayered structures. Within T2* profiles, estimates are more accurate after harmonics are removed, especially in the lower half of profiles.

  6. Symmetry based frequency domain processing to remove harmonic noise from surface nuclear magnetic resonance measurements

    NASA Astrophysics Data System (ADS)

    Hein, Annette; Larsen, Jakob Juul; Parsekian, Andrew D.

    2016-11-01

    Surface nuclear magnetic resonance (NMR) is a unique geophysical method due to its direct sensitivity to water. A key limitation to overcome is the difficulty of making surface NMR measurements in environments with anthropogenic electromagnetic noise, particularly constant frequency sources such as powerlines. Here we present a method of removing harmonic noise by utilizing frequency domain symmetry of surface NMR signals to reconstruct portions of the spectrum corrupted by frequency-domain noise peaks. This method supplements the existing NMR processing workflow and is applicable after despiking, coherent noise cancellation, and stacking. The symmetry based correction is simple, grounded in mathematical theory describing NMR signals, does not introduce errors into the dataset, and requires no prior knowledge about the harmonics. Modeling and field examples show that symmetry based noise removal reduces the effects of harmonics. In one modeling example, symmetry based noise removal improved signal to noise ratio in the data by 10%. This improvement had noticeable effects on inversion parameters including water content and the decay constant T2*. Within water content profiles, aquifer boundaries and water content are more accurate after harmonics are removed. Fewer spurious water content spikes appear within aquifers, which is especially useful for resolving multi-layered structures. Within T2* profiles, estimates are more accurate after harmonics are removed, especially in the lower half of profiles.

  7. First measurement of surface nuclear recoil background for argon dark matter searches

    NASA Astrophysics Data System (ADS)

    Xu, Jingke; Stanford, Chris; Westerdale, Shawn; Calaprice, Frank; Wright, Alexander; Shi, Zhiming

    2017-09-01

    One major background in direct searches for weakly interacting massive particles (WIMPs) comes from the deposition of radon progeny on detector surfaces. A dangerous surface background is the 206Pb nuclear recoils produced by 210Po decays. In this paper, we report the first characterization of this background in liquid argon. The scintillation signal of low energy Pb recoils is measured to be highly quenched in argon, and we estimate that the 103 keV 206Pb recoil background will produce a signal equal to that of a ˜5 keV (30 keV) electron recoil (40Ar recoil). In addition, we demonstrate that this dangerous 210Po surface background can be suppressed, using pulse shape discrimination methods, by a factor of ˜100 or higher, which can make argon dark matter detectors near background-free and enhance their potential for discovery of medium- and high-mass WIMPs. We also discuss the impact on other low background experiments.

  8. Nuclear-magnetic-resonance measurements of the hydrogen dynamics in nanocrystalline graphite

    NASA Astrophysics Data System (ADS)

    Stanik, E.; Majer, G.; Orimo, S.; Ichikawa, T.; Fujii, H.

    2005-08-01

    Hydrogen-loaded nanocrystalline graphite samples have been prepared by mechanical milling under a hydrogen atmosphere. Milling vials and balls made of agate and ZrO2 have been used to prepare samples with hydrogen contents between 1 and 2wt%. The proton nuclear-magnetic-resonance (H1-NMR) spectra of these samples are well represented by the sum of a broad Gaussian and a more narrow Lorentzian line corresponding to hydrogen in C-H covalent bonds as well as to hydrogen in methyl groups. The temperature dependence of the Lorentzian line can be ascribed to a hindered rotation of the methyl groups. The corresponding activation enthalpy of about 0.12eV has been deduced from the spin-lattice relaxation rates between 250 and 450K. Below about 200K the relaxation rates are temperature independent but they depend strongly on the NMR frequency and on the parameters of the sample preparation. The relaxation due to paramagnetic impurities as well as the cross relaxation of the proton spins with spins of quadrupolar impurity nuclei are proposed to contribute significantly to the measured spin-lattice relaxation rates.

  9. Nuclear spin dependence of the reaction of H(3)+ with H2. II. Experimental measurements.

    PubMed

    Crabtree, Kyle N; Kauffman, Carrie A; Tom, Brian A; Beçka, Eftalda; McGuire, Brett A; McCall, Benjamin J

    2011-05-21

    The nuclear spin dependence of the chemical reaction H(3)(+)+ H(2) → H(2) + H(3)(+) has been studied in a hollow cathode plasma cell. Multipass infrared direct absorption spectroscopy has been employed to monitor the populations of several low-energy rotational levels of ortho- and para-H(3)(+) (o-H(3)(+) and p-H(3)(+)) in hydrogenic plasmas of varying para-H(2) (p-H(2)) enrichment. The ratio of the rates of the proton hop (k(H)) and hydrogen exchange (k(E)) reactions α ≡ k(H)/k(E) is inferred from the observed p-H(3)(+) fraction as a function of p-H(2) fraction using steady-state chemical models. Measurements have been performed both in uncooled (T(kin) ∼ 350 K) and in liquid-nitrogen-cooled (T(kin) ∼ 135 K) plasmas, marking the first time this reaction has been studied at low temperature. The value of α has been found to decrease from 1.6 ± 0.1 at 350 K to 0.5 ± 0.1 at 135 K. © 2011 American Institute of Physics.

  10. Sheltering--a protective measure following an accidental atmospheric release from a nuclear power plant

    SciTech Connect

    Koch, J.; Tadmor, J.

    1988-06-01

    The effectiveness of sheltering the population for reducing radiological effects following an accidental release of radioactivity at a nuclear power plant was investigated. Different levels of respiratory protection and the administration of a thyroid blocking agent were also studied as possible complements to sheltering. Specific conditions were assumed, concerning the high protection factors of regular buildings and the high availability of civil defense shelters. Computations were performed by means of a probabilistic consequence model, which allows a comprehensive description of exposure modes and processes dealing with the implementation of sheltering and which takes into account a broad range of radiological effects. Sheltering, even in regular buildings, was found to be efficient in reducing early fatalities and other non-stochastic effects. However, it was shown that respiratory protection is also needed in order to alleviate stochastic effects and that, for this purpose, expedient individual filtration methods may be satisfactory. Under the conditions studied, sheltering was found to be preferable in most cases over evacuation, as the main immediate protective measure, unless evacuation can be carried out before the radioactive cloud reaches the populated area.

  11. Sheltering--a protective measure following an accidental atmospheric release from a nuclear power plant.

    PubMed

    Koch, J; Tadmor, J

    1988-06-01

    The effectiveness of sheltering the population for reducing radiological effects following an accidental release of radioactivity at a nuclear power plant was investigated. Different levels of respiratory protection and the administration of a thyroid blocking agent were also studied as possible complements to sheltering. Specific conditions were assumed, concerning the high protection factors of regular buildings and the high availability of civil defense shelters. Computations were performed by means of a probabilistic consequence model, which allows a comprehensive description of exposure modes and processes dealing with the implementation of sheltering and which takes into account a broad range of radiological effects. Sheltering, even in regular buildings, was found to be efficient in reducing early fatalities and other non-stochastic effects. However, it was shown that respiratory protection is also needed in order to alleviate stochastic effects and that, for this purpose, expedient individual filtration methods may be satisfactory. Under the conditions studied, sheltering was found to be preferable in most cases over evacuation, as the main immediate protective measure, unless evacuation can be carried out before the radioactive cloud reaches the populated area.

  12. Direct Measurement of Surface Dissolution Rates in Potential Nuclear Waste Forms: The Example of Pyrochlore.

    PubMed

    Fischer, Cornelius; Finkeldei, Sarah; Brandt, Felix; Bosbach, Dirk; Luttge, Andreas

    2015-08-19

    The long-term stability of ceramic materials that are considered as potential nuclear waste forms is governed by heterogeneous surface reactivity. Thus, instead of a mean rate, the identification of one or more dominant contributors to the overall dissolution rate is the key to predict the stability of waste forms quantitatively. Direct surface measurements by vertical scanning interferometry (VSI) and their analysis via material flux maps and resulting dissolution rate spectra provide data about dominant rate contributors and their variability over time. Using pyrochlore (Nd2Zr2O7) pellet dissolution under acidic conditions as an example, we demonstrate the identification and quantification of dissolution rate contributors, based on VSI data and rate spectrum analysis. Heterogeneous surface alteration of pyrochlore varies by a factor of about 5 and additional material loss by chemo-mechanical grain pull-out within the uppermost grain layer. We identified four different rate contributors that are responsible for the observed dissolution rate range of single grains. Our new concept offers the opportunity to increase our mechanistic understanding and to predict quantitatively the alteration of ceramic waste forms.

  13. Radiological investigations at the "Taiga" nuclear explosion site: Site description and in situ measurements.

    PubMed

    Ramzaev, V; Repin, V; Medvedev, A; Khramtsov, E; Timofeeva, M; Yakovlev, V

    2011-07-01

    In the summer of 2009, we performed a field survey of the "Taiga" peaceful underground nuclear explosion site, the Perm region, Russia (61.30° N, 56.60° E). The explosion was carried out by the USSR in 1971. This paper provides an extended summary of the available published data on the "Taiga" experiment. A detailed description of the site is illustrated by original aerial and ground-level photos. A large artificial lake (700 m long and 350 m wide) currently occupies the central area of the experimental site. The ground lip surrounding the lake is covered by a newly grown mixed forest. In situ measurements, performed in August 2009, revealed elevated levels of the γ-ray dose rate in air on the banks of the lake "Taiga". Two hot spots were detected on the eastern bank of the lake. The excess of the γ-ray radiation is attributable to the man-made radionuclides (60)Co and (137)Cs. The current external γ-ray dose rate to a human from the contaminations associated with the "Taiga" experiment was between 9 and 70 μSv per week. Periodic monitoring the site is recommended.

  14. Skeletal Muscle Quantitative Nuclear Magnetic Resonance Imaging and Spectroscopy as an Outcome Measure for Clinical Trials

    PubMed Central

    Carlier, Pierre G.; Marty, Benjamin; Scheidegger, Olivier; Loureiro de Sousa, Paulo; Baudin, Pierre-Yves; Snezhko, Eduard; Vlodavets, Dmitry

    2016-01-01

    Recent years have seen tremendous progress towards therapy of many previously incurable neuromuscular diseases. This new context has acted as a driving force for the development of novel non-invasive outcome measures. These can be organized in three main categories: functional tools, fluid biomarkers and imagery. In the latest category, nuclear magnetic resonance imaging (NMRI) offers a considerable range of possibilities for the characterization of skeletal muscle composition, function and metabolism. Nowadays, three NMR outcome measures are frequently integrated in clinical research protocols. They are: 1/ the muscle cross sectional area or volume, 2/ the percentage of intramuscular fat and 3/ the muscle water T2, which quantity muscle trophicity, chronic fatty degenerative changes and oedema (or more broadly, “disease activity”), respectively. A fourth biomarker, the contractile tissue volume is easily derived from the first two ones. The fat fraction maps most often acquired with Dixon sequences have proven their capability to detect small changes in muscle composition and have repeatedly shown superior sensitivity over standard functional evaluation. This outcome measure will more than likely be the first of the series to be validated as an endpoint by regulatory agencies. The versatility of contrast generated by NMR has opened many additional possibilities for characterization of the skeletal muscle and will result in the proposal of more NMR biomarkers. Ultra-short TE (UTE) sequences, late gadolinium enhancement and NMR elastography are being investigated as candidates to evaluate skeletal muscle interstitial fibrosis. Many options exist to measure muscle perfusion and oxygenation by NMR. Diffusion NMR as well as texture analysis algorithms could generate complementary information on muscle organization at microscopic and mesoscopic scales, respectively. 31P NMR spectroscopy is the reference technique to assess muscle energetics non-invasively during and

  15. Accurate optical measurement of nuclear polarization in optically pumped ^3He gas

    NASA Astrophysics Data System (ADS)

    Bigelow, N. P.; Nacher, P. J.; Leduc, M.

    1992-12-01

    Large nuclear polarizations M (over 80 %) can now be achieved in gaseous ^3He by optical pumping. The gas is excited by an RF discharge and is oriented using a high power LNA laser which is lamp pumped and tuned to the 2 ^3S-2 ^3P transition at 1.08 μm. In this paper we describe an experiment in which we measure M with high absolute precision. Our method is based on a change as a function of M in the ratio of σ or π polarized light absorbed from a weak probe beam by the 2 ^3S metastable atoms. The probe was delivered by a diode pumped LNA laser and propagated perpendicular to the direction of the magnetization. Simultaneous measurement of M was made by monitoring the degree of circular polarization \\cal{P} of the optical line at 668 nm emitted by the discharge. Our measurements show a linear relationship between M and \\cal{P} for all accessible M values and for a wide range of experimental conditions (sample pressure, magnetic field, RF discharge level, etc.). This provides a second method of measurement of the ^3He nuclear polarization which is simple to operate and is calibrated and is calibrated over a pressure range of 0.15 to 6.5 torr. On peut maintenant produire par pompage optique de fortes polarisations nucléaires M (M supérieure à 80 % dans l' ^3He gazeux. Le gaz est excité par une décharge radiofréquence et orienté à l'aide d'un laser LNA de forte intensité qui est pompé par des lampes et accordé sur la transition 2 ^3S-2 ^3P à 1,08 μm. Dans cet article, nous décrivons une expérience où nous mesurons M avec une grande précision absolue. Notre méthode est fondée sur la variation en fonction de M de l'absorption par les atomes métastables d'un faisceau sonde de faible intensité polarisé linéairement. Nous mesurons le rapport des absorptions pour des polarisations π et σ. Le faisceau sonde est un laser LNA pompé par diode qui se propage perpendiculairement à la direction de l'aimantation. Simultanément, nous mesurons M par le

  16. Time-dependent nuclear measurements of fuel-shell mix in ICF implosions at OMEGA

    NASA Astrophysics Data System (ADS)

    Rygg, J. Ryan

    2006-10-01

    Fuel-shell mix remains a pivotal concern in inertial confinement fusion (ICF), as it can preclude ignition. Mix is the result of saturation of Rayleigh-Taylor (RT) instability growth at a density interface that leads to small-scale, turbulent eddies and atomic-level mixing of cool, high-density fuel in the shell with hot, low-density fuel in the core. If sufficient mixing occurs, it will disrupt the formation of the ``hot-spot'' required for ignition. To sensitively probe the evolution and extent of mix in spherical implosions, the time dependence of the D^3He nuclear reaction rate was measured from implosions of capsules filled with pure ^3He. The capsule shell was comprised of a 1-μm layer of CD inside a 19-μm layer of CH. Nuclear burn will only occur in such capsules if there is sufficient mixing of D from the shell with hot ^3He in the core. By utilizing novel D^3He reaction-rate and proton spectrometers, all sensitive to the 14.7 MeV D^3He protons, a comprehensive, time dependent picture of mix was constructed. Important qualitative features were immediately evident: first, the shock burn of D^3He, always present for gas fills of D^3He, was absent, enabling a strong limit to be set on the amount and extent of D penetration into the ^3He. Second, the time necessary for RT instabilities to induce mix and to be heated by the hot core resulted in a 90 ps delay in the D^3He bang time as compared to bang time for implosions with D^3He fills. And third, when the gas pressure of ^3He was reduced from 20 to 4 atm, the extent of mix was enhanced by about a factor of 5. This work was supported in part by LLE, LLNL, the U.S. DoE, and the N.Y. State Energy Research and Development Authority.

  17. Sorption (Kd) measurements in support of dose assessments for Zion Nuclear Station Decommissioning

    SciTech Connect

    Yim S. P.; Sullivan T.; Milian, L.

    2012-12-12

    The Zion Nuclear Power Station is being decommissioned. ZionSolutions proposes to leave much of the below grade structures in place and to fill them with “clean” concrete demolition debris from the above grade parts of the facility. This study, commissioned by ZionSolutions and conducted by the Brookhaven National Laboratory (BNL) was performed to provide site-specific data for performance assessment calculations to support the request to terminate the NRC license and allow unrestricted use of the facility. Specifically, this study measured the distribution coefficient for five radionuclides of concern using site-specific soils and groundwater. The distributions coefficient is a measure of the amount of the radionuclide that will remain sorbed to the soil or concrete that is present relative to the amount that will remain in solution. A high distribution coefficient indicates most of the radionuclide will remain on the solid material and will not be available for transport by the groundwater. The radionuclides of concern are Fe-55, Co-60, Ni-63, Sr-90, and Cs-137. Tests were performed following ASTM C1733-10, Standard Test Methods for Distribution Coefficients of Inorganic Species by the Batch Method. Sr-85 was used in the testing as an analogue for Sr-90 because it behaves similarly with respect to sorption and has a gamma emission that is easier to detect than the beta emission from Sr-90. Site-specific soils included disturbed sand (sand removed during construction and used as backfill), native sand, silt/clay and silt. In addition, concrete cores from the Unit-1 Containment Building and the Crib House were broken into particles less than 2 mm in size and tested to obtain distribution coefficients for the five nuclides.

  18. Isotopomer measurement techniques in metabolic flux analysis I: nuclear magnetic resonance.

    PubMed

    Truong, Quyen X; Yoon, Jong Moon; Shanks, Jacqueline V

    2014-01-01

    Two-dimensional [(1)H, (13)C] heteronuclear single quantum correlation (HSQC) spectroscopy nuclear magnetic resonance (NMR) is a comprehensive tool in metabolic flux analysis using (13)C-labeling experiments. NMR is particularly relevant when extensive isotopomer measurements are required, such as for plant cells and tissues, which contain multiple cellular compartments. Several isotope isomers (isotopomers) can be detected and their distribution extracted quantitatively from a single 2-D HSQC NMR spectrum. For example, 2-D HSQC detects the labeling patterns of adjacent carbon atoms and provides the enrichment of individual carbon atoms of the amino acids and glucosyl and mannosyl units present in hydrolysates of glycosylated protein. The HSQC analysis can quantitatively distinguish differences between the glucosyl units in the starch hydrolysate and a protein hydrolysate of plant biomass: this specifies crucial information about compartmentalization in the plant system. The peak structures obtained from the HSQC experiment show multiplet patterns that are directly related to the isotopomer abundances. These abundances have a nonlinear relationship to the fluxes via isotopomer balancing. Fluxes are obtained from the numerical solution of these balances and a stoichiometric model that includes biomass composition data as well as consumption rates of carbohydrate and nitrogen sources. Herein, we describe the methods for the experimental measurements for flux analysis, i.e., determination of the biomass composition (lipid, protein, soluble sugar, and starch) as well as detailed procedures of acid hydrolysis of protein and starch samples and NMR sample preparation, using soybean embryo culture as the model plant system. Techniques to obtain the relative intensity of 16 amino acids and glucosyl units for protein hydrolysate and the glucosyl units of starch hydrolysate of soybean embryos in 2-D HSQC NMR spectra also are provided.

  19. Measurement of the ionization produced by sub-keV silicon nuclear recoils in a CCD dark matter detector

    NASA Astrophysics Data System (ADS)

    Chavarria, A. E.; Collar, J. I.; Peña, J. R.; Privitera, P.; Robinson, A. E.; Scholz, B.; Sengul, C.; Zhou, J.; Estrada, J.; Izraelevitch, F.; Tiffenberg, J.; de Mello Neto, J. R. T.; Torres Machado, D.

    2016-10-01

    We report a measurement of the ionization efficiency of silicon nuclei recoiling with sub-keV kinetic energy in the bulk silicon of a charge-coupled device (CCD). Nuclear recoils are produced by low-energy neutrons (<24 keV ) from a 124Sb-9Be photoneutron source, and their ionization signal is measured down to 60 eV electron equivalent. This energy range, previously unexplored, is relevant for the detection of low-mass dark matter particles. The measured efficiency is found to deviate from the extrapolation to low energies of the Lindhard model. This measurement also demonstrates the sensitivity to nuclear recoils of CCDs employed by DAMIC, a dark matter direct detection experiment located in the SNOLAB underground laboratory.

  20. Measurement of the ionization produced by sub-keV silicon nuclear recoils in a CCD dark matter detector

    DOE PAGES

    Chavarria, A. E.; Collar, J. I.; Peña, J. R.; ...

    2016-10-15

    We report a measurement of the ionization efficiency of silicon nuclei recoiling with sub-keV kinetic energy in the bulk silicon of a charge-coupled device (CCD). Nuclear recoils are produced by low-energy neutrons (<24 keV) from a 124Sb–9Be photoneutron source, and their ionization signal is measured down to 60 eV electron equivalent. This energy range, previously unexplored, is relevant for the detection of low-mass dark matter particles. The measured efficiency is found to deviate from the extrapolation to low energies of the Lindhard model. Furthermore, this measurement also demonstrates the sensitivity to nuclear recoils of CCDs employed by DAMIC, a darkmore » matter direct detection experiment located in the SNOLAB underground laboratory.« less

  1. Measurement of the ionization produced by sub-keV silicon nuclear recoils in a CCD dark matter detector

    SciTech Connect

    Chavarria, A. E.; Collar, J. I.; Peña, J. R.; Privitera, P.; Robinson, A. E.; Scholz, B.; Sengul, C.; Zhou, J.; Estrada, J.; Izraelevitch, F.; Tiffenberg, J.; de Mello Neto, J. R. T.; Machado, D. Torres

    2016-10-15

    We report a measurement of the ionization efficiency of silicon nuclei recoiling with sub-keV kinetic energy in the bulk silicon of a charge-coupled device (CCD). Nuclear recoils are produced by low-energy neutrons (<24 keV) from a 124Sb–9Be photoneutron source, and their ionization signal is measured down to 60 eV electron equivalent. This energy range, previously unexplored, is relevant for the detection of low-mass dark matter particles. The measured efficiency is found to deviate from the extrapolation to low energies of the Lindhard model. Furthermore, this measurement also demonstrates the sensitivity to nuclear recoils of CCDs employed by DAMIC, a dark matter direct detection experiment located in the SNOLAB underground laboratory.

  2. Monte Carlo study of a new experiment at RHIC measuring the nuclear effect for cosmic ray observations

    NASA Astrophysics Data System (ADS)

    Suzuki, T.; Itow, Y.; Kasahara, K.; Sako, T.; Torii, S.

    2017-09-01

    We have studied the potential performance of an experiment designed to measure neutral particles emitted in the forward region (η>6) of proton-nitrogen (p-N) inelastic collisions at √sNN=200 GeV. Such measurements will provide for the first time direct information about interactions between proton cosmic rays and the atmosphere at collider energies and will aid in the understanding of the nuclear effect of light-ions in the forward region which is expected to be dominated by the shadowing effect due to rescattering inside nuclear matter; this in turn will allow for the development of better air shower models. We first studied differences among the nuclear effects produced by the interaction models QGSJETII-03, DPMJET 3.04, and EPOS 1.99. We quantified the nuclear effects by calculationg the ratio of energy spectra of p-N collisions and proton-proton (p-p) collisions, which revealed a difference at the 30% level in the forward pion and neutron spectra. In order to assess the expected performance of an experiment designed to measure this difference, a full Monte Carlo calculation was conducted assuming the use of the Relativistic Heavy Ion Collider forward (RHICf) detector at Brookhaven National Laboratory installed at 1,800 cm from the interaction point. We have comfirmed that the detector would be able to identify and measure photons of energies below 100 GeV with position and energy resolutions better than 0.4 mm and 16%, respectively. One can discriminate the nuclear effect incorporated into various interaction models used in air shower simulations by measuring the photon spectrum in two different pseudorapidity ranges: η>10.5 and 8.8<η<10.2.

  3. Nuclear Spin Orientation Dependence of Magnetoconductance: A New Method for Measuring the Spin of Charged Excitations in the QHE

    SciTech Connect

    Bowers, C.R.; Reno, J.L.; Simmons, J.A.; Vitkalov, S.A.

    1998-12-01

    A new method for measuring the spin of the electrically charged ground state excitations m the Q$j~j quantum Hall effect ia proposed and demonstmted for the tirst time in GaAs/AIGaAs nndtiquantum wells. The method is &sed on the nuclear spin orientation dependence of" the 2D dc conductivity y in the quantum Hall regime due to the nuclear hyperfine interaction. As a demonstration of this method the spin of the electrically charged excitations of the ground state is determined at filling factor v = 1.

  4. 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.

  5. High resolution positron Q-value measurements and nuclear structure studies far from the stability line. Progress report

    SciTech Connect

    Avignone, F.T. III

    1982-02-28

    Research progress in briefly described, and details are presented in the attached preprints and reprints: (1) precision mass differences in light rubidium and krypton isotopes utilizing beta endpoint measurements; (2) precision mass measurements utilizing beta endpoints; (3) Monte Carlo calculations predicting the response of intrinsic GE detectors to electrons and positrons; and (4) reactor antineutrino spectra and nuclear spectroscopy of isotopes far from beta stability. (WHK)

  6. [Medical and psychological aspects of safety measures maintenance among nuclear and power station personnel].

    PubMed

    Ipatov, P L; Sorokin, A V; Basov, V I

    2004-01-01

    The article deals with 15-year experience of medical and psychophysiologic service in Medical and Sanitary Establishment No. 156 and Balakovo nuclear power station on providing reliability of occupational activities for the station personnel.

  7. Compound-Nuclear Reaction Cross Sections from Surrogate Measurements: Status and Challenges

    SciTech Connect

    Escher, Jutta

    2008-04-17

    The Surrogate nuclear reactions method, an indirect approach for determining cross sections for compound-nuclear reactions involving difficult-to-produce targets, is reviewed. The underlying formalism is outlined, the challenges involved in carrying out a complete Surrogate treatment are detailed, and the present status of the theory is summarized. The approximations employed in the analyses of Surrogate experiments are discussed and their validity is examined.

  8. Magnetic moments and g-factors in odd-A Ho isotopes

    NASA Astrophysics Data System (ADS)

    Tabar, E.; Yakut, H.; Kuliev, A. A.; Quliyev, H.; Hocşgör, G.

    2017-07-01

    The ground-state magnetic moment, g K factor and quenching spin gyromagnetic ratio have been calculated using the microscopic method based on the Quasiparticle Phonon Nuclear Model (QPNM) for 155-169Ho nuclei for the first time. It is shown that the residual spin-spin interactions are responsible for the core polarization, and because of the core polarization the spin gyromagnetic factors are quenched. By considering the core polarization effects, a satisfactory agreement is obtained for the computed ground state g K factor, which gives an intrinsic contribution to the magnetic moments. In order to assess the collective contribution to the magnetic moments, the rotational gyromagnetic factors g R have been also calculated within the cranking approximation using the single particle wave function of the axially symmetric Woods-Saxon potential. For the ground-state magnetic moments of odd-proton 155-165Ho nuclei, a good description of the experimental data is obtained with an accuracy of 0.01-0.1 μ N. From systematic trends, the quenching spin gyromagnetic factor, g K factor and magnetic moment have also been theoretically predicted for 167,169Ho where there is no existing experimental data. Supported by Scientific and Technological Research Council of Turkey (TUBITAK) (115F564)

  9. Measures of the environmental footprint of the front end of the nuclear fuel cycle

    SciTech Connect

    E. Schneider; B. Carlsen; E. Tavrides; C. van der Hoeven; U. Phathanapirom

    2013-11-01

    Previous estimates of environmental impacts associated with the front end of the nuclear fuel cycle (FEFC) have focused primarily on energy consumption and CO2 emissions. Results have varied widely. This work builds upon reports from operating facilities and other primary data sources to build a database of front end environmental impacts. This work also addresses land transformation and water withdrawals associated with the processes of the FEFC. These processes include uranium extraction, conversion, enrichment, fuel fabrication, depleted uranium disposition, and transportation. To allow summing the impacts across processes, all impacts were normalized per tonne of natural uranium mined as well as per MWh(e) of electricity produced, a more conventional unit for measuring environmental impacts that facilitates comparison with other studies. This conversion was based on mass balances and process efficiencies associated with the current once-through LWR fuel cycle. Total energy input is calculated at 8.7 x 10- 3 GJ(e)/MWh(e) of electricity and 5.9 x 10- 3 GJ(t)/MWh(e) of thermal energy. It is dominated by the energy required for uranium extraction, conversion to fluoride compound for subsequent enrichment, and enrichment. An estimate of the carbon footprint is made from the direct energy consumption at 1.7 kg CO2/MWh(e). Water use is likewise dominated by requirements of uranium extraction, totaling 154 L/MWh(e). Land use is calculated at 8 x 10- 3 m2/MWh(e), over 90% of which is due to uranium extraction. Quantified impacts are limited to those resulting from activities performed within the FEFC process facilities (i.e. within the plant gates). Energy embodied in material inputs such as process chemicals and fuel cladding is identified but not explicitly quantified in this study. Inclusion of indirect energy associated with embodied energy as well as construction and decommissioning of facilities could increase the FEFC energy intensity estimate by a factor of up

  10. Overview of a FPGA-based nuclear instrumentation dedicated to primary activity measurements.

    PubMed

    Bobin, C; Bouchard, J; Pierre, S; Thiam, C

    2012-09-01

    In National Metrology Institutes like LNE-LNHB, renewal and improvement of the instrumentation is an important task. Nowadays, the current trend is to adopt digital boards, which present numerous advantages over the standard electronics. The feasibility of an on-line fulfillment of nuclear-instrumentation functionalities using a commercial FPGA-based (Field-Programmable Gate Array) board has been validated in the case of TDCR primary measurements (Triple to Double Coincidence Ratio method based on liquid scintillation). The new applications presented in this paper have been included to allow either an on-line processing of the information or a raw-data acquisition for an off-line treatment. Developed as a complementary tool for TDCR counting, a time-to-digital converter specifically designed for this technique has been added. In addition, the description is given of a spectrometry channel based on the connection between conventional shaping amplifiers and the analog-to-digital converter (ADC) input available on the same digital board. First results are presented in the case of α- and γ-counting related to, respectively, the defined solid angle and well-type NaI(Tl) primary activity techniques. The combination of two different channels (liquid scintillation and γ-spectrometry) implementing the live-time anticoincidence processing is also described for the application of the 4πβ-γ coincidence method. The need for an optimized coupling between the analog chain and the ADC stage is emphasized. The straight processing of the signals delivered by the preamplifier connected to a HPGe detector is also presented along with the first development of digital filtering.

  11. Measurement of the ionization yield of nuclear recoils in liquid argon at 80 and 233 keV

    NASA Astrophysics Data System (ADS)

    Bondar, A.; Buzulutskov, A.; Dolgov, A.; Grishnyaev, E.; Polosatkin, S.; Shekhtman, L.; Shemyakina, E.; Sokolov, A.

    2014-10-01

    The energy calibration of nuclear recoil detectors is of primary importance to rare-event experiments such as those of direct dark matter search and coherent neutrino-nucleus scattering. In particular, such a calibration is performed by measuring the ionization yield of nuclear recoils in liquid Ar and Xe detection media, using neutron elastic scattering off nuclei. In the present work, the ionization yield for nuclear recoils in liquid Ar has for the first time been measured in the higher energy range, at 80 and 233 keV, using a two-phase Cryogenic Avalanche Detector (CRAD) and DD neutron generator. The ionization yield in liquid Ar at an electric field of 2.3 kV/cm amounted to 7.8+/-1.1 and 9.7+/-1.3 \\text{e}^-/\\text{keV} at 80 and 233 keV, respectively. The Jaffe model for nuclear recoil-induced ionization, in contrast to that of Thomas-Imel, can probably consistently describe the energy dependence of the ionization yield.

  12. Suppression of Zeeman gradients by nuclear polarization in double quantum dots.

    PubMed

    Frolov, S M; Danon, J; Nadj-Perge, S; Zuo, K; van Tilburg, J W W; Pribiag, V S; van den Berg, J W G; Bakkers, E P A M; Kouwenhoven, L P

    2012-12-07

    We use electric dipole spin resonance to measure dynamic nuclear polarization in InAs nanowire quantum dots. The resonance shifts in frequency when the system transitions between metastable high and low current states, indicating the presence of nuclear polarization. We propose that the low and the high current states correspond to different total Zeeman energy gradients between the two quantum dots. In the low current state, dynamic nuclear polarization efficiently compensates the Zeeman gradient due to the g-factor mismatch, resulting in a suppressed total Zeeman gradient. We present a theoretical model of electron-nuclear feedback that demonstrates a fixed point in nuclear polarization for nearly equal Zeeman splittings in the two dots and predicts a narrowed hyperfine gradient distribution.

  13. Helium diffusion coefficient measurements in R7T7 nuclear glass by 3He(d,α) 1H nuclear reaction analysis

    NASA Astrophysics Data System (ADS)

    Chamssedine, F.; Sauvage, T.; Peuget, S.; Fares, T.; Martin, G.

    2010-05-01

    The immobilization of fission products and minor actinides by vitrification is the reference process for industrial management of high-level radioactive wastes generated by spent fuel reprocessing. Radiation damage and radiogenic helium accumulation must be specifically studied to evaluate the effects of minor actinide alpha decay on the glass long-term behavior under repository conditions. A specific experimental study was conducted for a comprehensive evaluation of the behavior of helium and its diffusion mechanisms in borosilicate nuclear waste glass. Helium production was simulated by external implantation with 3He ions at a concentration (≈1 at.%) 30 times higher than obtained after 10,000 years of storage. Helium diffusion coefficients as a function of temperature were extracted from the depth profiles after annealing. The 3He(d,α) 1H nuclear reaction analysis (NRA) technique was successfully adopted for low-temperature in situ measurements of depth profiles. Its high depth resolution revealed helium mobility at temperatures as low as 253 K and the presence of a trapped helium fraction. The diffusion coefficients of un-trapped helium atoms follow an Arrhenius law between 253 K and 323 K. An activation energy of 0.55 ± 0.03 eV was determined, which is consistent with a process controlled by diffusion in the glass free volume.

  14. 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…

  15. 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…

  16. 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.

  17. Driving mechanism for damping and g-factor in non-amorphous ferromagnetic CoFeZr ultrathin films

    NASA Astrophysics Data System (ADS)

    Le Graët, C.; Spenato, D.; Beaulieu, N.; Dekadjevi, D. T.; Jay, J.-Ph.; Pogossian, S. P.; Warot-Fonrose, B.; Ben Youssef, J.

    2016-07-01

    We demonstrate that an in-plane uniaxial anisotropy may be induced in non-amorphous soft CoFeZr films. We used broadband ferromagnetic resonance spectroscopy and complex permeability spectra to investigate the spin dynamics in CoFeZr films. We report a systematic study of the FM thickness on the fundamental dynamic parameters such as the effective magnetisation, the g-factor and relaxation mechanisms. Our study reveals that the decrease of the effective magnetisation mesured with FMR with thickness is not due to perpendicular anisotropy but to low dimentionality. Moreover, we observed a decrease of the g-factor with thickness and a modification of the ratio of the orbital to the spin magnetic moment. These films exhibit good high-frequency performance red (i.e. high permeability in a broad frequency range and a low damping) at low thickness of about a few nanometers.

  18. Response of sheep lymphocytes to PHA: quantitation by nuclear volume measurement and cell counts (40764)

    SciTech Connect

    Chandra, P.; Chanana, A.D.; Joel, D.D.

    1980-03-01

    Phytohemagglutinin response of peripheral blood lymphocytes (PBL) of sheep was studied. Assessment of proliferative response was performed by determination of nuclear volumes and cell counts in cultures from 14 sheep and by incorporation of tritiated thymidine in cultures in four additional sheep. PBL of sheep were found to transform and proliferate with PHA similarly to human peripheral blood lymphocytes with minor differences. Quantitation of the proliferative response by determining the cell count and nuclear volumes provided more information on cell kinetics in culture than the commonly used isotope-labeled thymidine incorporation method.

  19. Advanced nondestructive examination technologies for measuring fatigue damage in nuclear power plant components

    SciTech Connect

    MacDonald, P.E.; Shah, V.N.; Akers, D.W.

    1995-12-01

    This paper presents recent results from an ongoing project at the Idaho National Engineering Laboratory (INEL) to develop advanced nondestructive methods to characterize the aging degradation of nuclear power plant pressure boundary components. One of the advanced methods, positron annihilation, is being developed for in situ characterization of fatigue damage in nuclear power plant piping and other components. This technique can detect and correlate the microstructural changes that are precursors of fatigue cracking in austenitic stainless steel components. In fact, the initial INEL test results show that the method can detect fatigue damage in stainless steel ranging from a few percent of the fatigue life up to 40 percent.

  20. Radioactive fallout from nuclear weapons. A review of airborne transport, effects and measures

    NASA Astrophysics Data System (ADS)

    Bergman, R.; Lindqvist, S.; Johansson, L.; Schelin, O.; Lagerstedt, O.; Edvarson, K.; Finck, R.; Danielson, G.

    1983-02-01

    The state of the art of radioactive fallout problems in Sweden was reviewed. Consequences of various fallout situations for the population are stressed, and information directed towards authorities involved in the planning for protective actions is given. The study emphasizes fallout caused by nuclear explosions outside Swedish territory, i.e., when Sweden is not directly involved in a nuclear war. Distribution and properties of fallout fields are described. Radiation effects on man from external sources as well as internal sources are considered. Consequences for agriculture and food production are investigated. Radiation sensitive materials such as electronic components are discussed, as well as possible protective actions.

  1. Measurement of 37Ar to support technology for On-site Inspection under the Comprehensive Nuclear-Test-Ban Treaty

    SciTech Connect

    Aalseth, Craig E.; Day, Anthony R.; Haas, Derek A.; Hoppe, Eric W.; Hyronimus, Brian J.; Keillor, Martin E.; Mace, Emily K.; Orrell, John L.; Seifert, Allen; Woods, Vincent T.

    2011-10-01

    On-Site Inspection (OSI) is a key component of the verification regime for the Comprehensive Nuclear-Test-Ban Treaty (CTBT). Measurements of radionuclide isotopes created by an underground nuclear explosion are a valuable signature of a Treaty violation. Argon-37 is produced from neutron interaction with calcium in soil, 40Ca(n,α)37Ar. For OSI, the 35-day half-life of 37Ar provides both high specific activity and sufficient time for completion of an inspection before decay limits sensitivity. This paper presents a low-background internal-source gas proportional counter with an 37Ar measurement sensitivity level equivalent to 45.1 mBq/SCM in whole air.

  2. Measurement of 37Ar to support technology for On-Site Inspection under the Comprehensive Nuclear-Test-BanTreaty

    NASA Astrophysics Data System (ADS)

    Aalseth, C. E.; Day, A. R.; Haas, D. A.; Hoppe, E. W.; Hyronimus, B. J.; Keillor, M. E.; Mace, E. K.; Orrell, J. L.; Seifert, A.; Woods, V. T.

    2011-10-01

    On-Site Inspection (OSI) is a key component of the verification regime for the Comprehensive Nuclear-Test-Ban Treaty (CTBT). Measurements of radionuclide isotopes created by an underground nuclear explosion are a valuable signature of a Treaty violation. Argon-37 is produced by neutron interaction with calcium in soil, 40Ca( n, α) 37Ar. For OSI, the 35-day half-life of 37Ar provides both high specific activity and sufficient time for completion of an inspection before decay limits sensitivity. This paper presents a low-background internal-source gas proportional counter with an 37Ar measurement sensitivity level equivalent to 45 mBq/SCM in wholeair.

  3. SU-E-T-234: LET Measurement Using Nuclear Emulsion and Monte Carlo Simulation for Proton Beam.

    PubMed

    Shin, J; Cho, S; Park, S; Lee, S; Kwak, J; Kim, S; Morishima, K

    2012-06-01

    The significant issue of particle therapy such as proton and carbon ion biological effect on tumors and normal tissue. This effect closely connected with linear-energy-transfer (LET). This work presents a Monte Carlo study using GEANT4 and the verification using Nuclear Emulsion to show LET for proton beam. National Cancer Center (NCC) has IBA Beam Nozzle and cyclotron for proton therapy. We use proton beam bragg peak range 14cm. Also, we already developed the simulation using GEANT4 and finished validation for scattering proton beam. In our simulation, we make same condition with experimental setup.Nuclear emulsion films interleaved with tissue equivalent absorbers can be fruitfully used to reconstruct proton tracks with very high precision. This Nuclear emulsion film has been supported from Nagoya University, analyzed in Pusan University, was irradiated with a therapeutic proton beam at NCC. The Emulsion packs was located at entrance and bragg peak region of proton. This position means low and high LET region. The scanning of the emulsions has been performed at Nagoya University, where a fully automated microscopic scanning technology has been developed for the OPERA experiment on neutrino oscillations. We could see the reconstructed track of proton scanning emulsion. From film scanning, we got the LET distribution at low and high LET region for several proton tracks. Simulation results was similar distribution within standard deviation in acceptance level. Also we got the RBE distribution using LET measurement for proton beam. We measured LET at entrance and bragg peak region using Monte Carlo study and Nuclear Emulsion film, for NCC proton beam. This results means the good observation of LET using the nuclear emulsion. And this method can be used successfully in medical field. © 2012 American Association of Physicists in Medicine.

  4. Studies of the EPR g factors and the local structures for the orthorhombic Er 3+ centers in garnets

    NASA Astrophysics Data System (ADS)

    Wu, Shao-Yi; Dong, Hui-Ning

    2005-05-01

    The perturbation formulas of the EPR g factors gx, gy and gz for a 4f11 ion in orthorhombic symmetry are established. In these formulas, the contributions to the g factors arising from the second-order perturbation terms and the admixture of various states are taken into account. The above formulas are applied to the orthorhombic Er3+ centers in YAG, YGG and LuGG garnets. By analyzing their g factors, we find that the polar angles θj‧ of the impurity-ligand bonds related to the Z axis of the crystals in these Er3+ centers are smaller than the host angles θj in pure crystals, whereas the azimuthal angles ϕj ‧ related to the X axis in the impurity centers are larger than the corresponding ϕj in the hosts. The g factors and their anisotropies Δg [= gz - (gx + gy)/2] and δg (= gx - gy) for Er3+ in the garnets based on the above local structural parameters are in good agreement with the observed values. In addition, the angular distortions Δθ (=θj‧ -θj) or Δϕ (=ϕj‧ -ϕj) obtained by analyzing the EPR data in this work are different from Δθ2 or Δϕ2 (for only the second set of ligands, i.e., j = 2) based on the superposition model crystal-field analysis in the previous work. The validity of the results is discussed.

  5. Dimensional reduction of the Luttinger Hamiltonian and g -factors of holes in symmetric two-dimensional semiconductor heterostructures

    NASA Astrophysics Data System (ADS)

    Miserev, D. S.; Sushkov, O. P.

    2017-02-01

    The spin-orbit interaction of holes in zinc-blende semiconductors is much stronger than that of electrons. This makes the hole systems very attractive for possible spintronics applications. In three dimensions (3D), the dynamics of holes is described by well-known Luttinger Hamiltonian. However, most recent spintronics applications are related to two-dimensional (2D) heterostructures where dynamics in one direction is frozen due to quantum confinement. The confinement results in dimensional reduction of the Luttinger Hamiltonian, 3 D →2 D . Due to the interplay of the spin-orbit interaction, the external magnetic field, and the lateral gate potential imposed on the heterostructure, the reduction is highly nontrivial and as yet unknown. In the present work we perform the reduction and hence derive the general effective Hamiltonian which describes spintronics effects in symmetric 2D heterostructures. In particular, we do the following: (i) derive the spin-orbit interaction and the Darwin interaction related to the lateral gate potential, (ii) determine the momentum-dependent out-of-plane g -factor, (iii) point out that there are two independent in-plane g -factors, (iv) determine momentum dependencies of the in-plane g -factors.

  6. 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).

  7. The incentives and feasibility for direct measurement of spent nuclear fuel characteristics in the Federal Waste Management System

    SciTech Connect

    Not Available

    1989-08-01

    The purpose of this work is to assess the nature and extent of the need for direct measurements of spent fuel characteristics within the utility and federal portions of the waste management system, and to evaluate the capability and limitations of various measurement devices for meeting those needs. The need for direct measurement is evaluated relative to the alternative sources of the spent fuel characteristics data required for the safe and effective operation of the system. The results of this work are intended to support Federal Waste Management System (FWMS) planners by identifying the probable and potential requirements for direct measurements and for making related programmatic decisions based on the adequacy or development requirements for appropriate measurement technologies to support the needs of facility and equipment designers and operators. The designers and operators of the FWMS need to know the characteristics of the spent nuclear fuel (SNF) and related wastes that will be handled, processed, stored, transported and ultimately emplaced underground for final disposal. There are typically two basic sources of this needed information: (1) historical records of measurements made when the fuel was being fabricated or was producing energy; and (2) direct measurements made during handling prior to disposal. Historical records would include the design and fabrication records of the nuclear fuel assemblies and the subsequent utility records of reactor and core operations. 21 refs., 3 figs., 5 tabs.

  8. Measurements of individual radiation doses in residents living around the Fukushima Nuclear Power Plant.

    PubMed

    Nagataki, Shigenobu; Takamura, Noboru; Kamiya, Kenji; Akashi, Makoto

    2013-11-01

    At the outset of the accident at Fukushima Daiichi Nuclear Power Plant in March 2011, the radiation doses experienced by residents were calculated from the readings at monitoring posts, with several assumptions being made from the point of view of protection and safety. However, health effects should also be estimated by obtaining measurements of the individual radiation doses. The individual external radiation doses, determined by a behavior survey in the "evacuation and deliberate evacuation area" in the first 4 months, were <5 mSv in 97.4% of residents (maximum: 15 mSv). Doses in Fukushima Prefecture were <3 mSv in 99.3% of 386,572 residents analyzed. External doses in Fukushima City determined by personal dosimeters were <1 mSv/3 months (September-November, 2011) in 99.7% of residents (maximum: 2.7 mSv). Thyroid radiation doses, determined in March using a NaI (TI) scintillation survey meter in children in the evacuation and deliberate evacuation area, were <10 mSv in 95.7% of children (maximum: 35 mSv). Therefore, all doses were less than the intervention level of 50 mSv proposed by international organizations. Internal radiation doses determined by cesium-134 ((134)C) and cesium-137 ((137)C) whole-body counters (WBCs) were <1 mSv in 99% of the residents, and the maximum thyroid equivalent dose by iodine-131 WBCs was 20 mSv. The exploratory committee of the Fukushima Health Management Survey mentions on its website that radiation from the accident is unlikely to be a cause of adverse health effects in the future. In any event, sincere scientific efforts must continue to obtain individual radiation doses that are as accurate as possible. However, observation of the health effects of the radiation doses described above will require reevaluation of the protocol used for determining adverse health effects. The dose-response relationship is crucial, and the aim of the survey should be to collect sufficient data to confirm the presence or absence of radiation health

  9. Use of the Nuclear Materials Identification System (NMIS) for enhanced receipt confirmation measurements at the Oak Ridge Y-12 Plant

    SciTech Connect

    J.K. Mattingly; T.E. Valentine; J.T. Mihalczo

    2000-05-30

    The Nuclear Materials Identification System (NMIS) developed by the Instrumentation and Controls Division of the Oak Ridge National Laboratory and the Oak Ridge Y-12 Plant has been used at the Oak Ridge Y-12 plant to perform enhanced receipts confirmation measurements providing mass estimates on low mass HEU metal pieces in shipping containers. For this application, NMIS was used in its active mode with a small Cf source on one side of the shipping container and detectors on the other side. Second order correlation measurements with calibration standards were utilized to obtain the mass of HEU. This was the first use of NMIS for receipts at the Y-12 Plant. This was a cost-effective method for measuring the mass of receipts with as many as 64 items measured in one day. This paper describes the reasons for using the NMIS for this application. The measurement technique and evaluation of the measurement data for this application are also described.

  10. A nonintrusive nuclear monitor for measuring liquid contents in sealed vessels

    NASA Technical Reports Server (NTRS)

    Singh, J. J.; Mall, G. H.

    1984-01-01

    A nonintrusive nuclear technique for monitoring fluid contents in sealed vessels, regardless of the fluid distribution inside the vessels is described. The technique is applicable to all-g environments. It is based on the differences in Cesium-137 gamma ray attenuation coefficients in air and the test liquids.

  11. 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.

  12. Measurements and Observations of 134Cs and 137Cs around a Nuclear Power Plant in Busan, South Korea

    NASA Astrophysics Data System (ADS)

    Chong, H. Y.; Park, J. N.; Kim, J. S.

    2015-12-01

    The purpose of this study is to know the change of representative species 134Cs and 137Cs of artificial radionuclides from the nuclear power station nearby for the last five years(2010~2014). The Kori Nuclear Power Plant, nuclear power facility located near Busan, is located in the south-east coast of Korea and about 21km north-east away from the Haeundae and about 25km south away from the Ulsan. An administrative district is Jangan-eup, Gijang-gun, Busan, Korea. A point was selected on the basis of the "Environmental Radiation Monitoring Plan around Nuclear Power Plants" and periodically samples were collected and analyzed. The samples were collected from the soils of the surface in the Wolnae area (NW, 1.7km). The soil samples were analyzed by gamma spectrometer with High Purity Germanium detector (HPGe) of 40% relative efficiency and were measured for 80,000 sec. As a results of soil analysis, 137Cs were detected in samples only selected in March 2013. The activity concentration of 137Cs founded in the soil sample was 0.513±0.052Bq/kg-dry. In the other hands, the concentration of 137Cs in the year 2010, 2011, 2012, and 2014 were below the minimum detectable activity (MDA). 40K, natural radionuclides which is widely present, was detected in the soil samples and other artificial radionuclides were not detected. The result of overall comparison of the environmental radioactivity survey around Kori Nuclear Power Plant for the last five years is that radioactivity levels are within average range. However, it is necessary to continue to carefully observe a fine change in regional or the monthly radiation concentration.

  13. Predictions of the nuclear activation of materials on LDEF produced by the space radiation environment and comparison with flight measurements.

    PubMed

    Armstrong, T W; Colborn, B L; Harmon, B A; Laird, C E

    1996-11-01

    Model calculations have been made to compare with the induced radioactivity measured for materials on the LDEF satellite. Predictions and data comparisons are made for aluminum spacecraft components and for vanadium and nickel samples placed at multiple locations on the spacecraft. The calculated vs observed activations provide an indication of present model uncertainties in predicting nuclear activation as well as the magnitude and directionality of the trapped proton environment for low-Earth orbit missions. Environment model uncertainties based on the activation measurements are consistent with the uncertainties evaluated using other LDEF radiation dosimetry data.

  14. Hydrolysis Profiles of Formalin Fixed Paraffin-Embedded Tumors Based on IOD (Integrated Optical Density) and Nuclear Texture Feature Measurements

    PubMed Central

    Fležar, Margareta; Us‐Krašovec, Marija; žganec, Mario; Lavrenčak, Jaka; Golouh, Rastko

    1999-01-01

    The aim of the study was to determine optimal hydrolysis time for the Feulgen DNA staining of archival formalin fixed paraffin‐embedded surgical samples, prepared as single cell suspensions for image cytometric measurements. The nuclear texture features along with the IOD (integrated optical density) of the tumor nuclei were analysed by an automated high resolution image cytometer as a function of duration of hydrolysis treatment (in 5 N HCl at room temperature). Tissue blocks of breast carcinoma, ovarian serous carcinoma, ovarian serous tumor of borderline malignancy and leiomyosarcoma were included in the study. IOD hydrolysis profiles showed plateau between 30 and 60 min in the breast carcinoma and leiomyosarcoma, and between 40 and 60 min in the ovarian serous carcinoma and ovarian serous tumor of borderline malignancy. Most of the nuclear texture features remained stable after 20 min of hydrolysis treatment. Our results indicate that the optimal hydrolysis time for IOD and for nuclear texture feature measurements, was between 40 and 60 min in the cell preparations from tissue blocks of three epithelial and one soft tissue tumor. PMID:10866273

  15. Nuclear Fission

    NASA Astrophysics Data System (ADS)

    Denschlag, J. O.

    This chapter first gives a survey on the history of the discovery of nuclear fission. It briefly presents the liquid-drop and shell models and their application to the fission process. The most important quantities accessible to experimental determination such as mass yields, nuclear charge distribution, prompt neutron emission, kinetic energy distribution, ternary fragment yields, angular distributions, and properties of fission isomers are presented as well as the instrumentation and techniques used for their measurement. The contribution concentrates on the fundamental aspects of nuclear fission. The practical aspects of nuclear fission are discussed in http://dx.doi.org/10.1007/978-1-4419-0720-2_57 of Vol. 6.

  16. Measuring Process Dynamics and Nuclear Migration for Clones of Neural Progenitor Cells

    PubMed Central

    De La Hoz, Edgar Cardenas; Winter, Mark R.; Apostolopoulou, Maria; Temple, Sally

    2016-01-01

    Neural stem and progenitor cells (NPCs) generate processes that extend from the cell body in a dynamic manner. The NPC nucleus migrates along these processes with patterns believed to be tightly coupled to mechanisms of cell cycle regulation and cell fate determination. Here, we describe a new segmentation and tracking approach that allows NPC processes and nuclei to be reliably tracked across multiple rounds of cell division in phase-contrast microscopy images. Results are presented for mouse adult and embryonic NPCs from hundreds of clones, or lineage trees, containing tens of thousands of cells and millions of segmentations. New visualization approaches allow the NPC nuclear and process features to be effectively visualized for an entire clone. Significant differences in process and nuclear dynamics were found among type A and type C adult NPCs, and also between embryonic NPCs cultured from the anterior and posterior cerebral cortex. PMID:27878138

  17. Measuring Process Dynamics and Nuclear Migration for Clones of Neural Progenitor Cells.

    PubMed

    De La Hoz, Edgar Cardenas; Winter, Mark R; Apostolopoulou, Maria; Temple, Sally; Cohen, Andrew R

    2016-10-01

    Neural stem and progenitor cells (NPCs) generate processes that extend from the cell body in a dynamic manner. The NPC nucleus migrates along these processes with patterns believed to be tightly coupled to mechanisms of cell cycle regulation and cell fate determination. Here, we describe a new segmentation and tracking approach that allows NPC processes and nuclei to be reliably tracked across multiple rounds of cell division in phase-contrast microscopy images. Results are presented for mouse adult and embryonic NPCs from hundreds of clones, or lineage trees, containing tens of thousands of cells and millions of segmentations. New visualization approaches allow the NPC nuclear and process features to be effectively visualized for an entire clone. Significant differences in process and nuclear dynamics were found among type A and type C adult NPCs, and also between embryonic NPCs cultured from the anterior and posterior cerebral cortex.

  18. Measures of the Environmental Footprint of the Front End of the Nuclear Fuel Cycle

    SciTech Connect

    Brett Carlsen; Emily Tavrides; Erich Schneider

    2010-08-01

    Previous estimates of environmental impacts associated with the front end of the nuclear fuel cycle have focused primarily on energy consumption and CO2 emissions. Results have varied widely. Section 2 of this report provides a summary of historical estimates. This study revises existing empirical correlations and their underlying assumptions to fit to a more complete set of existing data. This study also addresses land transformation, water withdrawals, and occupational and public health impacts associated with the processes of the front end of the once-through nuclear fuel cycle. These processes include uranium mining, milling, refining, conversion, enrichment, and fuel fabrication. Metrics are developed to allow environmental impacts to be summed across the full set of front end processes, including transportation and disposition of the resulting depleted uranium.

  19. High precision analysis of isotopic composition for samples used for nuclear cross-section measurements

    NASA Astrophysics Data System (ADS)

    Shibahara, Yuji; Hori, Jun-ichi; Takamiya, Koichi; Fujii, Toshiyuki; Fukutani, Satoshi; Sano, Tadafumi; Harada, Hideo

    2017-09-01

    For the accuracy improvement of nuclear data of minor actinides and long-lived fission products in the project of "Research and development for Accuracy Improvement of neutron nuclear data on Minor Actinides", the isotopic compositions of two Am samples (241Am sample and 243Am sample) were analyzed by thermal ionization mass spectrometry. Only the peak of 241Am was observed in the analysis of 241Am sample, and level of isotopic impurities were improved from 0.1% to 0.0004%. In the analysis of 243Am sample, the peak of unreported isotope of 242mAm was observed in addition to the peaks of 243Am and 241Am. The mass spectrometry also showed that 243Am sample has other unreported impurities such as 239Pu and 240Pu.

  20. 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.