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Sample records for 7li nuclear magnetic

  1. (6)Li, (7)Li Nuclear Magnetic Resonance Investigation of Lithium Coordination in Binary Phosphate Glasses

    Alam, T.M.; Boyle, T.J.; Brow, R.K.; Conzone, S.

    1999-02-08

    {sup 6}Li and {sup 7}Li solid state magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy has been used to investigate the local coordination environment of lithium in a series of xLi{sub 2}O {center_dot} (1-x)P{sub 2}O{sub 5} glasses, where 0.05 {le} x {le} 0.55. Both the {sup 6}Li and {sup 7}Li show chemical shift variations with changes in the Li{sub 2}O concentration, but the observed {sup 6}Li NMR chemical shifts closely approximate the true isotropic chemical shift and can provide a measure of the lithium bonding environment. The {sup 6}Li NMR results indicate that in this series of lithium phosphate glasses the Li atoms have an average coordination between four and five. The results for the metaphosphate glass agree with the coordination number and range of chemical shifts observed for crystalline LiPO{sub 3}. An increase in the {sup 6}Li NMR chemical shift with increasing Li{sub 2}O content was observed for the entire concentration range investigated, correlating with increased cross-linking of the phosphate tetrahedral network by O-Li-O bridges. The {sup 6}Li chemical shifts were also observed to vary monotonically through the anomalous glass transition temperature (T{sub g}) minimum. This continuous chemical shift variation shows that abrupt changes in the Li coordination environment do not occur as the Li{sub 2}O concentration is increased, and such abrupt changes can not be used to explain the T{sub g} minimum.

  2. Local structure of LiB3O5 single crystal from 7Li nuclear magnetic resonance

    The local structure of LiB3O5 single crystal was investigated with 7Li (I=3/2) nuclear magnetic resonance measurements. We observed four different spectra, which could be divided into two groups corresponding to two kinds of lithium atoms, LiA and LiB, lying at crystallographically equivalent sites and magnetically inequivalent sites. From these results, the quadrupole coupling constants and the asymmetry parameters were determined at room temperature and are e2qQ/h=143±1 kHz and η=0.6±0.1 for 7Li. The directions of the principal axes of the electric field gradient tensors were also determined. The spectra for the two groups have the same principal values of the electric field gradient tensor, but different orientations, and originate from magnetically inequivalent sites. Also, the 7Li spin-lattice relaxation rate was measured, and the measured relaxation rate was found to be proportional to the temperature. The temperature-dependent single phonon process is considered to be more effective than the Raman process for nuclear quadrupole relaxation. In addition, we discuss the correlation between the asymmetry parameter and the largest nonlinear optical coefficient

  3. 7Li nuclear magnetic resonance studies of dynamics in a ternary gel polymer electrolyte based on polymeric ionic liquids

    The influence of the polymeric ionic liquid (PIL) Poly(diallyldimethylammonium bis(trifluoromethylsulfonyl) imide) (PDADMATFSI) on the lithium dynamics was investigated in a ternary gel polymer electrolyte consisting of PDADMATFSI as stabilizing polymer, ionic liquid (1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl) imide, P14TFSI) and lithium salt (lithium bis(trifluoromethylsulfonyl) imide, LiTFSI). The diffusion coefficient of the lithium ions is investigated by pulsed-field-gradient NMR, the conductivity of the electrolyte is determined by impedance spectroscopy. The local lithium dynamics is characterized by 7Li spin lattice relaxation rates (R1). The relaxation rates are well described by Blombergen-Purcell-Pound (BPP) theory at all polymer concentrations (up to 45 mol%), implying that the Li dynamics is governed by one single motional mode. Interestingly, activation energies for this motion decrease from 20 kJ/mol to 15 kJ/mol with increasing polymer content and are independent on the salt content. We thus conclude that the polymer is interacting with the anion coordination shell, which is accompanied by a very beneficial effect on the local lithium dynamics, as the polymer PDADMATFSI reduces the Li-TFSI interactions. This result is promising for further investigations for potential use of PDADMATFSI-containing gels as electrolytes in energy storage devices

  4. Spontaneous Lithium Transportation via LiMn2O4/Electrolyte Interface Studied by 6/7Li Solid-State Nuclear Magnetic Resonance

    Highlights: • Spontaneous Li+ exchange between LiMn2O4 and LiPF6-based electrolyte was studied. • 6/7Li solid-state NMR techniques were developed to examine the exchange. • The exchange occurs for stoichiometric LiMn2O4 but not in Li-excess LiMn2O4. • The exchange was approximated by the 1st-order reaction with the rate of 0.024 min-1. • The suppression in Li-excess LiMn2O4 was ascribed to excess amount of Mn4+. - Abstract: Lithium transportation across the interface of LiMn2O4/LiPF6-based electrolyte was studied by 6/7Li solid-state NMR with 6Li-enriched LiPF6. For almost stoichiometric LiMn2O4, we show that exchange of lithium ions occurs across an electrolyte/electrode interface just by immersing LiMn2O4 powder into LiPF6-based electrolyte, while such transportation is suppressed in Li-excess LiMn2O4. The exchange was approximated by the 1st-order reaction, and the rate was estimated from the 6Li/7Li intensities to be 0.024 min−1 at room temperature. The lithium ions penetrated into the surface of a LiMn2O4 particle reach to the core with a time scale of a few hours at room temperature. The suppression of the exchange in Li-excess LiMn2O4 was ascribed to the presence of excess amount of Mn4+

  5. In situ 7Li and 133Cs Nuclear Magnetic Resonance Investigations on the Role of Cs+ Additive in Lithium-Metal Deposition Process

    Hu, Jian Z.; Zhao, Zhenchao; Hu, Mary Y.; Feng, Ju; Deng, Xuchu; Chen, Xilin; Xu, Wu; Liu, Jun; Zhang, Jiguang

    2016-02-01

    Application of Li metal electrode in rechargeable lithium battery is hindered by safety concerns due to dendritic growth on the electrode over several charge-discharge cycles. We have found previously that adding low concentration Cs+ in electrolytes can promote smooth deposition of lithium onto metal electrode during repeated charge-discharge cycling using idea Li|Cu battery without the using of a separator. In this work, quantitative in situ 7Li and 133Cs NMR investigations using real planar symmetric lithium battery cells with and without Cs+ additives were carried out. It is found that the deposited lithium atoms on electrodes are highly porous. Detailed analysis of the data were carried out by separating the 7Li signal from deposited lithium that was oriented parallel to the electrode surface with the signal from the Li-metal nanorodes oriented perpendicular or nearly perpendicular to the electrode surface. The results demonstrate that addition of Cs+ can significantly enhance both the formation of uniform Li nanorods, and the reversibility of electrode. In situ 133Cs NMR directly confirms that Cs+ migrates to the electrode to form a positively charged electrostatic shield during cycling process. Combining the quantitative analysis of the orientation dependent signals of deposited metal Li and previous ex-situ results, different Li deposition models are proposed. During cycling process, more “active” lithium participates in the Li transfer between the electrode and nanorods for the battery with Cs+, while for the battery without Cs+ more dead and thinker lithium rods are formed and Li transfer between dendrites from different electrodes dominates.

  6. Extremely slow cation exchange processes in Li4SiO4 probed directly by two-time 7Li stimulated-echo nuclear magnetic resonance spectroscopy

    Lithium self-diffusion in the low-temperature modification of polycrystalline lithium ortho-silicate Li4SiO4 is investigated by 7Li two-time stimulated echo NMR spectroscopy. Extremely slow Li exchange processes were directly monitored between 300 and 433 K by recording spin-alignment echoes as a function of mixing time varying over six decades from 10-5 to 10 s. In the investigated temperature range the hopping correlation functions show biexponential behaviour. Whereas the first decay step reflects directly Li jumps between electrically different sites, the second one is simply induced by the decay of alignment order due to quadrupolar relaxation. The echo decay rates τ-1 (101 s-1≤τ-1≤104 s-1), which can be identified with Li jump rates, show Arrhenius behaviour with an activation energy of 0.53(1) eV. The directly measured jump rates are in good agreement with those obtained recently by one- and two-dimensional 6Li exchange MAS NMR reported in the literature

  7. Electron affinity of (7)Li calculated with the inclusion of nuclear motion and relativistic corrections.

    Stanke, Monika; Kedziera, Dariusz; Bubin, Sergiy; Adamowicz, Ludwik

    2007-10-01

    Explicitly correlated Gaussian functions have been used to perform very accurate variational calculations for the ground states of (7)Li and (7)Li(-). The nuclear motion has been explicitly included in the calculations (i.e., they have been done without assuming the Born-Oppenheimer (BO) approximation). An approach based on the analytical energy gradient calculated with respect to the Gaussian exponential parameters was employed. This led to a noticeable improvement of the previously determined variational upper bound to the nonrelativistic energy of Li(-). The Li energy obtained in the calculations matches those of the most accurate results obtained with Hylleraas functions. The finite-mass (non-BO) wave functions were used to calculate the alpha(2) relativistic corrections (alpha=1c). With those corrections and the alpha(3) and alpha(4) corrections taken from Pachucki and Komasa [J. Chem. Phys. 125, 204304 (2006)], the electron affinity (EA) of (7)Li was determined. It agrees very well with the most recent experimental EA. PMID:17919011

  8. Determination of nuclear reduced transition probabilities by 7Li ion induced Coulomb excitation

    Recently the authors observed that the first excited state of 7Li nucleus was excited in 7Li ion-Cu collision in the energy range 4.9 to 11.9 MeV, and the excitation process was via Coulomb excitation. By using the well known B (E2; g.s. 3-/2 - 478 keV, 1-/2) value of 7Li nucleus and the 7Li induced Coulomb excitation yields of both 7Li projectile and targets, the authors determined the reduced transition probabilities for low-lying states of some medium weight nuclei. The reduced transition probabilities determined this way are free from uncertainties due to target thickness and incident particle collection

  9. Electrical conductivity, differential scanning calorimetry, X-ray diffraction, and 7Li nuclear magnetic resonance studies of n-CxH(2x+1)OSO3Li (x = 12, 14, 16, 18, and 20)

    Electrical conductivity (σ), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) measurements of n-C xH(2x+1)OSO3Li (x= 12, 14, 16, 18, and 20) crystals were performed as a function of temperature. In addition, σ, DSC, and XRD observations of n-C xH(2x+1)OSO3Na and n-C xH(2x+1)OSO3K (x= 12, 14, 16, 18, and 20) crystals were carried out for comparison. DSC results of the salts revealed several solid-solid phase transitions with large entropy changes (ΔS). For n-C 18H37OSO3Li and n-C 20H41OSO3Li salts, each melting point produced a small ΔSmp value compared with the total entropy change in the solid phases (ΔStr1+ΔStr2). Additionally, Li + ion diffusion was detected in the highest temperature solid phases. For K salts, larger σ values were detected for potassium alkylsulfates compared with those reported for alkyl carboxylate. 7Li NMR spectra of n-C 18H37OSO3Li crystals recorded in the low-temperature phase showed large asymmetry parameters, suggesting the Li + ions are localized at asymmetric sites in the crystals

  10. Search for solar axion emission from $^7$Li and D(p,$\\gamma)^3$He nuclear decays with the CAST $\\gamma$-ray calorimeter

    Andriamonje, S; Autiero, D; Barth, K; Belov, A; Beltran, B; Brauninger, H; Carmona, J M; Cebrian, S; Collar, J I; Dafni, T; Davenport, M; Di Lella, L; Eleftheriadis, C; Englhauser, J; Fanourakis, G; Ferrer-Ribas, E; Fischer, H; Franz, J; Friedrich, P; Geralis, T; Giomataris, I; Gninenko, S; Gomez, H; Hasinoff, M; Heinsius, F H; Hoffmann, D.H H; Irastorza, I G; Jacoby, J; Jakovcic, K; Kang, D; Konigsmann, K; Kotthaus, R; Krcmar, M; Kousouris, K; Kuster, M; Lakic, B; Lasseur, C; Liolios, A; Ljubicic, A; Lutz, G; Luzon, G; Miller, D W; Morales, J; Ortiz, A; Papaevangelou, T; Placci, A; Raffelt, G; Riege, H; Rodriguez, A; Ruz, J; Savvidis, I; Semertzidis, Y; Serpico, P; Stewart, L; Vieira, J D; Villar, J; Vogel, J; Walckiers, L; Zioutas, K

    2010-01-01

    We present the results of a search for a high-energy axion emission signal from 7Li (0.478 MeV) and D(p,gamma)3He (5.5 MeV) nuclear transitions using a low-background gamma-ray calorimeter during Phase I of the CAST experiment. These so-called "hadronic axions" could provide a solution to the long-standing strong-CP problem and can be emitted from the solar core from nuclear M1 transitions. This is the first such search for high-energy pseudoscalar bosons with couplings to nucleons conducted using a helioscope approach. No excess signal above background was found.

  11. A computer study of the experimental feasibility of observing the nuclear excitation of 7Li by reactor antineutrinos

    Avignone, F. T.; Donnelly, T. W.

    1981-01-01

    A computer study of the feasibility of observing the 0.478 MeV γ-ray following the antineutrino excitation of 7Li has been carried out in a simple geometry involving two large Ge detectors placed on the axis inside a 20 kg target of natural lithium. The background γ-ray flux was assumed to be that observed by Fiorini and his co-workers in their search for neutrinoless double beta decay of 76Ge. The target was assumed to be inside a rectangular live shield of NaI(Tl) which has a wall thickness of 10.16 cm. The results for the Weinberg-Salam model clearly show that the direct observation of this reaction is feasible even if the background is almost two orders of magnitude more intense than the background observed by Fiorini et al. This conclusion was found to be valid even if most of the background originates inside the cryostat itself. If the background is no more than three times as intense as that observed by Fiorini et al., the excitation can at least be observed with a larger target and with no NaI(Tl) annulus.

  12. Electrical conductivity, differential scanning calorimetry, X-ray diffraction, and {sup 7}Li nuclear magnetic resonance studies of n-C{sub x}H{sub (2x+1)}OSO{sub 3}Li (x = 12, 14, 16, 18, and 20)

    Hirakawa, Satoru [Yokohama City University, Graduate School of Nanobioscience (Japan); Morimoto, Yoshiaki [Yokohama City University, International College of Arts and Sciences (Japan); Honda, Hisashi, E-mail: hhonda@yokohama-cu.ac.jp [Yokohama City University, Graduate School of Nanobioscience (Japan)

    2015-04-15

    Electrical conductivity (σ), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) measurements of n-C {sub x}H{sub (2x+1)}OSO{sub 3}Li (x= 12, 14, 16, 18, and 20) crystals were performed as a function of temperature. In addition, σ, DSC, and XRD observations of n-C {sub x}H{sub (2x+1)}OSO{sub 3}Na and n-C {sub x}H{sub (2x+1)}OSO{sub 3}K (x= 12, 14, 16, 18, and 20) crystals were carried out for comparison. DSC results of the salts revealed several solid-solid phase transitions with large entropy changes (ΔS). For n-C {sub 18}H{sub 37}OSO{sub 3}Li and n-C {sub 20}H{sub 41}OSO{sub 3}Li salts, each melting point produced a small ΔS{sub mp} value compared with the total entropy change in the solid phases (ΔS{sub tr1}+ΔS{sub tr2}). Additionally, Li {sup +} ion diffusion was detected in the highest temperature solid phases. For K salts, larger σ values were detected for potassium alkylsulfates compared with those reported for alkyl carboxylate. {sup 7}Li NMR spectra of n-C {sub 18}H{sub 37}OSO{sub 3}Li crystals recorded in the low-temperature phase showed large asymmetry parameters, suggesting the Li {sup +} ions are localized at asymmetric sites in the crystals.

  13. A new mass value for 7Li

    Nagy, Sz; Suhonen, M; Schuch, R; Blaum, K; Björkhage, M; Bergström, I; 10.1103/PhysRevLett.96.163004

    2012-01-01

    A high-accuracy mass measurement of 7Li was performed with the Smiletrap Penning trap mass spectrometer via a cyclotron frequency comparison of Li3+ and H2+. A new atomic mass value of 7Li has been determined to be 7.016,003,425,6,(45)u with a relative uncertainty of 0.63 ppb. It has uncovered a discrepancy as large as 14 sigma (1.1 micro u) deviation relative to the literature value given in the Atomic-Mass Evaluation AME 2003. The importance of the improved and revised 7Li mass value, for calibration purposes in nuclear-charge radii and atomic mass measurements of the neutron halos 9Li and 11Li, is discussed.

  14. Electric dipolarizability of 7Li

    Sudhir R Jain; Arun K Jain; S Kailas

    2008-12-01

    We calculate the electric dipolarizability of 7Li nucleus within the cluster model and estimate a value of about 0.0188 fm3. We also discuss the possibility of observing this in the scattering of 7Li from a 208Pb target at energies about 30 MeV.

  15. Spectroscopy of particle-phonon coupled states in $^{133}$Sb by the cluster transfer reaction of $^{132}$Sn on $^{7}$Li: an advanced test of nuclear interactions

    We propose to investigate, with MINIBALL coupled to T-REX, the one-valence-proton $^{133}$Sb nucleus by the cluster transfer reaction of $^{132}$Sn on $^{7}$Li. The excited 133Sb will be populated by transfer of a triton into $^{132}$Sn, followed by the emission of an $\\alpha$-particle (detected in T-REX) and 2 neutrons. The aim of the experiment is to locate states arising from the coupling of the valence proton of $^{133}$Sb to the collective low-lying phonon excitations of $^{132}$Sn (in particular the 3$^−$). According to calculations in the weak-coupling approach, these states lie in the 4$\\, - \\,$5 MeV excitation energy region and in the spin interval 1/2$\\, - \\,$ 19/2, i.e., in the region populated by the cluster transfer reaction. The results will be used to perform advanced tests of different types of nuclear interactions, usually employed in the description of particle-phonon coupled excitations. States arising from couplings of the proton with simpler core excitations, involving few nucleons only...

  16. Nuclear reaction of 10 B (n, α) 7 Li and grain size effects on the production of free radicals in alanine

    In general, it is important to know the physical and chemical properties of any material that is exposed to ionizing radiation. In particular, in dosimetric work, the amount of the absorbed doses by these materials is of much interest, in such a way that several methods have been developed in the past. An important and quantitatively accessible radiation effect in organic substances is the production of free radicals that can be easily measured by 'ELECTRON PARAMAGNETIC RESONANCE SPECTROSCOPY (EPR)'. Numerous studies have been now been made on pure D L-Alanine irradiated with different radiation sources. Examination of the irradiated samples reveals the production of a stable free radical (CH3 - CH. -COOH). In particular, gamma and electron irradiated D L-Alanine has received wide attention in the high doses interval (10 - 105 Gy). In contrast, there are very few EPR studies on thermal neutron radiation induced free radicals in pure D L-alanine. This may be due to the weak EPR signals observed in the irradiated samples. The objective of this work is to study for the first time the increase of the radical yield produced in neutron irradiated borated alanine by the EPR technique. For this purpose alanine has been mixed with borax in different stoichiometric proportions and grain sizes. When the mixture is neutron irradiated, the boron of the borax may experience a neutron capture reaction, 10 B (n, α) 7 Li. With this nuclear reaction it is supposed that the α particles will may impinge on the alanine molecules, producing in this way extra free radicals. Samples were irradiated in the thermal column of a Triga Mark III nuclear reactor with a thermal neutron flux of 5 x 10 7 n/Cm2 -s. A signal enhancement of up to 1260 % is observed when samples of alanine-borax were intimately mixed in a stoichiometric ratio of 1:1. We also studied dosimetric characteristics of the mixed samples such as: a) Sensibility. b) Accuracy. c) Traceability. d) Stability. e)Fading. f

  17. Neutron capture radiography to determine the concentration of natural boron in leaves using the nuclear reaction 10B(n,α)7Li

    Neutron capture radiography (NCR) is a nuclear analytical imaging method. It is based on using thermal neutron induced nuclear reactions, such as (n,p), (n,α) or (n,f). Clearly NCR can be used for the detection of only those nuclides whose cross-section (σ) for one of these nuclear reactions is not too low. With σ being indicated in barns (1 barn 10-28m2) in brackets, this is the case especially with 14N (1.83), 35Cl (0.48), 40K (4.4) for (n,p) reactions; 6Li (941.4), 10B (3836), 17O (0.24), 35S (0.14), 40K (0.39) for (n,α) reactions; and 235U (583) and 239Pu (742) for neutron induced fissions (n,f). Some of these nuclear reactions are characteristic of stable isotopes (14N, 6Li, 10B, 17O) of chemical elements that are highly relevant for biology but have no radioactive isotope usable in practice. It is possible to use these stable isotopes for the labelling and analytical imaging of the corresponding elements almost as easily as with radioactive tracers when they exist. Some of these nuclear reactions are characteristic of stable isotopes (14N, 6Li, 10B, 17O) of chemical elements that are highly relevant for biology but have no radioactive isotope usable in practice. It is possible to use these stable isotopes for the labelling and analytical imaging of the corresponding elements almost as easily as with radioactive tracers when they exist. In conventional NCR studies, the biological specimen (a histological section in most cases) is laid against an appropriate detector (most often a film of cellulose nitrate or polycarbonate), and then this whole assembly is irradiated with thermal neutrons. The impact of the ionizing particles (p,α, fission fragments) emitted by the nuclear reactions creates latent tracks in the detecting film. Using an appropriate chemical treatment (most often by dipping the detectors in a strong alkaline solution), the latent tracks are enlarged to the size of tracks visible with an optical microscope. The features (especially the size

  18. Energy levels in (7Li) nucleus

    The energies of the normal-parity states and positive parity states in (7Li) nucleus are calculated, using many-particle nuclear shell-model, and the harmonic oscillator-wave-functions, over the residual interaction of the Gaussian from the Serber force. Spin-orbit interactions are neglected. The kinetic energy is introduced as a variant quantity, through the variation of the harmonic oscillator parameter (r0) (r02=h/mw). Finally, we separate the ''spurious'' states (one quantum excitations of the center of mass of the nucleus) by the effect of the operator (R-i), for the coordinate of the center of mass on the different wave-functions of the ground state-configurations. The calculations show that the energy of the positive-parity states, separated into two groups; the first in the energy region (10-20 Mev) and described by the symmetries (43), (421); and the second group in the energy region (26-46 Mev) and described by the symmetries (31), (3211). 9 tabs.; 3 figs.; 64 refs

  19. Reaction mechanism study of 7Li(7Li, 6He) reaction at above Coulomb barrier energies

    V V Parkar; V Jha; S Santra; B J Roy; K Ramachandran; A Shrivastava; K Mahata; A Chatterjee; S Kailas

    2009-02-01

    The elastic scattering and the 6He angular distributions were measured in 7Li + 7Li reaction at two energies, lab = 20 and 25 MeV. FRDWBA calculations have been performed to explain the measured 6He data. The calculations were very sensitive to the choice of the optical model potentials in entrance and exit channels. The one-step proton transfer was found to be the dominant reaction mechanism in 6He production.

  20. Contribution to the study of the influence of the Pauli principle and of its modelization in nuclear reactions between heavy ions: application to the reaction 7Li

    A simple model based on the Hackenbroich approach of the R.G.M. theory which simulates the Pauli principle among clusters has been derived in the following way. The exact antisymmetrization between the nucleon belonging to a given cluster has been kept. The contribution of the exchange terms between two different clusters, which give rise to non-local potentials, has been simulated by the matrix elements of an effective local, l-dependent, energy-independent nucleon-nucleon potential. With these potentials (added to the regular n-n interaction) the low energy levels of 8Be and 7Li as well as the phase shifts l=0,2,4 for α-α scattering and l=0 to 4 for α-n and α-t scattering for energies below 10MeV (c.m.) have been calculated. Good agreement between exact antisymmetrized and modelized calculations is achieved. With this model elastic and inelastic scattering of α on 7Li have been calculated. The 7Li has been described in terms of α,t clusters. The coupling with the 8Be + t channel has been taken into account. A good agreement between experimental data and modelized theoretical calculations is achieved when the projectile energy is less than 5MeV (lab. system). It appears that the coupling with the 8Be + t channel is not negligible even below this channel threshold

  1. Magnetic catalysis in nuclear matter

    Haber, Alexander; Preis, Florian; Schmitt, Andreas

    2014-01-01

    A strong magnetic field enhances the chiral condensate at low temperatures. This so-called magnetic catalysis thus seeks to increase the vacuum mass of nucleons. We employ two relativistic field-theoretical models for nuclear matter, the Walecka model and an extended linear sigma model, to discuss the resulting effect on the transition between vacuum and nuclear matter at zero temperature. In both models we find that the creation of nuclear matter in a sufficiently strong magnetic field becom...

  2. Nuclear Magnetic Resonance Imaging of Li-ion Battery

    D. Ohno

    2010-12-01

    Full Text Available Nuclear magnetic resonance (NMR imaging has high sensitivity to proton (1H and lithium (7Li. It is a useful measurement for electrolyte in Li-ion battery. 1H NMR images of lithium ion battery which is composed of LiMn2O4 / LiClO4 + propylene carbonate (PC / Li-metal have been studied. 1H NMR images of electrolyte near cathode material (LiMn2O4 showed anomalous intensity distribution, which was quite inhomogeneous. From NMR images as a function of repetition time (TR, it was concluded that the anomalous intensity distribution was not due to change of relaxation time but an indirect (spatial para-magnetization effect from cathode material. The paramagnetization induced by high magnetic field distorts linearity of magnetic gradient field, leading to apparent intensity variance. This functional image is an easy diagnostic measurement for magnetization of cathode material, which allows the possibility to check uniformity of cathode material and change of magnetization under electrochemical process.

  3. Exploring contributions from incomplete fusion in $^{6,7}$Li+$^{209}$Bi and $^{6,7}$Li+$^{198}$Pt reactions

    Parkar, V V; Kailas, S

    2016-01-01

    We use the breakup absorption model to simultaneously describe the measured cross-sections of the Complete fusion (CF), Incomplete fusion (ICF), and Total fusion (TF) in nuclear reactions induced by weakly bound nuclei $^{6,7}$Li on $^{209}$Bi and $^{198}$Pt targets. The absorption cross-sections are calculated using the Continuum Discretized Coupled Channels (CDCC) method with different choices of short range imaginary potentials to get the ICF, CF and TF cross-sections. It is observed that the cross-sections for deuteron-ICF/deuteron-capture are of similar magnitude as the $\\alpha$-ICF/$\\alpha$-capture, in case of $^{6}$Li projectile, while the cross-sections for triton-ICF/triton-capture is more dominant than $\\alpha$-ICF/$\\alpha$-capture in case of $^{7}$Li projectile. Both these observations are also corroborated by the experimental data. The ratio of ICF to TF cross-sections, which defines the value of fusion suppression factor is found to be in agreement with the data available from the literature. The...

  4. $^{7}$Li abundances in halo stars testing stellar evolution models and the primordial $^{7}$Li abundance

    Chaboyer, B; Brian Chaboyer

    1994-01-01

    A large number of stellar evolution models with [Fe/H] = -2.3 and -3.3 have been calculated in order to determine the primordial .sup(7)Li abundance and to test current stellar evolution models by a comparison to the extensive database of Li abundances in extremely metal poor halo stars observed by Thorburn (1994). Standard models do a good job of fitting the observed Li abundances in stars hotter than 5600 K. They predict a primordial ^7Li abundance of log N(Li) = 2.24\\pm 0.03. Models which include microscopic diffusion predict a downward curvature in the .sup(7)Li destruction isochrones at hot temperatures which is not present in the observations. Thus, the observations clearly rule out models which include uninhibited microscopic diffusion of .sup(7)Li from the surface of the star. The [Fe/H] = -2.3 stellar models which include both diffusion and rotational mixing provide an excellent match to the observations. Both the plateau stars and the heavily depleted cool stars are well fit by these models. The rot...

  5. Angular correlations and decay branching ratio for excited state of 7Li*(7,45 MeV) in reactions 7Li(alpha, alpha)7Li*

    Measurements of differential cross-sections of alpha-particle inelastic scattering by 7Li nuclei and 7Li(alpha, alpha 6Li)n, 7Li(alpha, alpha alpha)t reactions have been performed at the energy Ea = 27,2 MeV. Probability of 7Li*(7,45 MeV) decay into 6Li + n channel has been determined from the ratio of cross-sections measured in kinematically complete and incomplete experiments. The large discrepancy of this value (P 0,49 ± 0,06) and of those obtained at the study of 7Li*(7,45 MeV) decay in binary reactions can be explained by the influence of Coulomb field of accompanied alpha-particle on the decay of near-threshold resonances in three-particle reactions

  6. Nuclear magnetic resonance study of sulfate reorientations in LiNaSO4

    A nuclear magnetic resonance study of the sulfate ion reorientations in β-LiNaSO4 has been carried out. The influence of the SO4 reorientational jumps on the quadrupolar interactions of 7Li nuclei was investigated by a jump reorientational model, which has not previously been applied to sulfates. The activation energy required for the SO4 reorientations was found to be 0.19 eV. It was also revealed that the SO4 reorientational disorder should be associated with a small anomaly of a heat capacity at around 600 K, which was previously observed experimentally. (paper)

  7. Nuclear magnetic resonance study of sulfate reorientations in LiNaSO4

    Shakhovoy, R. A.; Rakhmatullin, A.; Deschamps, M.; Sarou-Kanian, V.; Bessada, C.

    2016-05-01

    A nuclear magnetic resonance study of the sulfate ion reorientations in β-LiNaSO4 has been carried out. The influence of the SO4 reorientational jumps on the quadrupolar interactions of 7Li nuclei was investigated by a jump reorientational model, which has not previously been applied to sulfates. The activation energy required for the SO4 reorientations was found to be 0.19 eV. It was also revealed that the SO4 reorientational disorder should be associated with a small anomaly of a heat capacity at around 600 K, which was previously observed experimentally.

  8. Line shapes of prompt γ-ray from 7*Li produced in 10B(n,α)7*Li reaction

    Prompt γ-ray spectra of recoil 7*Li produced in the 10B(n,α)7*Li reaction were measured using neutron beam. The observed Doppler broadening energy spectra were satisfactorily reproduced by a simulation where the velocity degradation of 7*Li within its lifetime of 1.05x10-13 s was estimated using the LSS theory. Our successful line-shape analysis was applied to non-destructive state analysis of trace amounts of boron. (author)

  9. Nuclear Current and Magnetic Rotation

    PENG Jing; XING Li-Feng

    2009-01-01

    The magnetic rotational bands based on the configuration πh211/2 ⊕Vh-211/2 in 142 Gd are investigated with the newly developed tilted axis cranking relativistic mean field (RMF) theory with and without nuclear current.The effect of the nuclear current is discussed by comparing the total Routhians,single particle levels,electromagnetic transition probabilities B(M1) and B(E2) in self-consistent tilted axis cranking RMF calculation with those obtained without the nuclear current.The nuclear currents are found to play an important role in the magnetic rotation of nuclei.

  10. Constraints on Ωb from nucleosynthesis of 7Li in the standard big bang model

    We update standard big bang nucleosynthesis (SBBN) calculations on the basis of recent nuclear physics compilations (NACRE in particular), experimental and theoretical works. By a Monte Carlo technique, we calculate the uncertainties on the light element yields (4He, D, 3He and 7Li) related to nuclear reactions. The results are compared to observations that are thought to be representative of the corresponding primordial abundances. It is found that 7Li could lead to more stringent constraints on the baryonic density of the universe (Ωbh2) than deuterium, because of much higher observation statistics and an easier extrapolation to primordial values. The confrontation of SBBN results with 7Li observations is of special interest since other independent approaches have also recently provided Ωbh2 values: (i) the anisotropies of the cosmic microwave background by the BOOMERANG, CBI, DASI and MAXIMA experiments and (ii) the Lyman-α forest at high redshift. A comparison between these results obtained by different methods provides a test of their consistency and could provide a better determination of the baryonic density in the universe. However, the agreement between Ωbh2 values deduced from SBBN calculation and 7Li observation on the one hand and CMB observations on the other hand is only marginal

  11. Nuclear Bag Model and Nuclear Magnetic Moments

    Liu, Liang-Gang

    1999-01-01

    In 1991, we proposed a model in which nucleus is treated as a spherical symmetric MIT bag and nucleon satisfies the MIT bag model boundary condition. The model was employed to calculate nuclear magnetic moments. The results are in good agreement with experiment data. Now, we found this model is still interesting and illuminating.

  12. Reactions 7Li(e,6He) pe' and 7Li(e,6Li) ne' at intermediate excitation energies

    The reactions 7Li(e,6He) pe' and 7Li(e,6Li) ne' have been studied at intermediate excitation energies. Angular distributions as well as energy distributions are presented. The experimental cross sections are compared to the results obtained from a simple model

  13. GHz nuclear magnetic resonance

    Cross, T.A.; Drobny, G.; Trewhella, J.

    1994-12-01

    For the past dozen years, 500- and 600-MHz spectrometers have become available in many laboratories. The first 600-MHz NMR spectrometer (at Carnegie Mellon University) was commissioned more than 15 years ago and, until 1994, represented the highest field available for high-resolution NMR. This year, we have witnessed unprecedented progress in the development of very high field magnets for NMR spectroscopy, including the delivery of the first commercial 750-MHz NMR spectrometers. In addition, NMR signals have been obtained from 20-Tesla magnets (850 MHz for {sup 1}H`s) at both Los Alamos National Laboratory and Florida State University in the NHMFL (National High Magnetic Field Laboratory). These preliminary experiments have been performed in magnets with 100-ppm homogeneity, but a 20-Tesla magnet developed for the NHMFL will be brought to field this year with a projected homogeneity of 0.1 ppm over a 1-cm-diam spherical volume.

  14. Fusion around the barrier for 7Li + 12C

    A Mukherjee; M Dasgupta; D J Hinde; C R Morton; A C Berriman; R D Butt; J O Newton; H Timmers

    2001-07-01

    Fusion cross-sections for the 7Li + 12C reaction have been measured at energies above the Coulomb barrier by the direct detection of evaporation residues. The heavy evaporation residues with energies below 3 MeV could not be separated out from the -particles in the spectrum and hence their contribution was estimated using statistical model calculations. The present work indicates that suppression of fusion cross-sections due to the breakup of 7Li may not be significant for 7Li + 12C reaction at energies around the barrier.

  15. Static and dynamic moments of the 7Li nucleus

    The data of Weller et al. (1985) on the tensor analysing powers for elastic and inelastic Coulomb scattering of aligned 7Li ions have been reanalyzed in order to obtain information on the values of the four 7Li moments Q, B(E2)↑, τ11 and τ12. It is shown that a single set of values, chosen primarily to be consistent with the value of Q measured by molecular techniques and the values of B(E2)↑ and τ12. required to fit unpolarized 7Li data, and also with the theoretical constraint τ11≅-[τ12], gives a good fit to the aligned 7Li data. 19 refs., 6 figs

  16. Nuclear magnetic gamma double resonance

    A number of problems corresponding to different variants of experiments using nuclear magnetic-gamma double resonance (NMGDR) are theoretically investigated. Calculation is carried out and its results are compared to experimental ones concerning NMGDR for tantalum. Time dynamics of the source or scatterer nucleus sublevel populations under double resonance conditions with non-uniform initial population of this nucleus sublevels is studied

  17. Magnetometer of nuclear magnetic resonance

    We present a nuclear magnetic resonance magnetometer that measures magnetic fields, between 2,500 gauss and 5,000 gauss, with an accuracy of a few parts per million. The circuit of the magnetometer, based on a marginal oscillator, permits a continuous tunning in the frequency range comprised between 10.0 MHz, with a signal to noise ratio of about 20. The radiofrequency amplifier is of the cascode type in integrated circuit and it operates with two 9V batteries. The modulation is at 35 Hz and it is provided by an external oscillator. The instrument is compact, inexpensive and easy to operate; it can also be used for didactic purposes to show the phenomenon of magnetic nuclear resonance and its main characteristics. (author)

  18. 7Li NMR studies of lithium transport in human erythrocytes

    Lithium transport in human erythrocytes was investigated by 7Li NMR spectroscopy. The intra- and extracellular pools of Li+ were distinguished by the addition to the red cell suspension of a cell-impermeable shift reagent, dysprosium(III) triphosphate. It was found that, for therapeutic levels of lithium used in the US (where the typical plasma (Li+) concentration range is 0.5-1.2 mM), a shift reagent concentration of 3 mM is sufficient to achieve clear chemical shift separation between the two 7Li+ NMR resonances. Despite competition between Li+ and other mono- and divalent cations for the shift reagent, the intra and extracellular 7Li+ NMR signals are clearly separated (approximately 3 ppM) even in the presence of physiologically relevant concentrations of Na+, K+, Mg2+, and Ca2+. Addition of an ionophore, monesin, to a K+-only RBC (red blood cell) suspension induces passive Li+ transport, which can be monitored by following the relative intensities of the two 7Li+ resonances. It is concluded that the 7Li NMR method is suitable for the noninvasive study of Li+ transport in human erythrocytes and that it shows great promise as a tool for the investigation of the bioinorganic chemistry of lithium. 24 references, 3 figures, 1 table

  19. Evanescent Waves Nuclear Magnetic Resonance

    Halidi, El Mohamed; Nativel, Eric; Akel, Mohamad;

    2016-01-01

    Nuclear Magnetic Resonance spectroscopy and imaging can be classified as inductive techniques working in the near- to far-field regimes. We investigate an alternative capacitive detection with the use of micrometer sized probes positioned at sub wavelength distances of the sample in order to char...... a new road to a better understanding of the evanescent waves component in NMR with the opportunity to perform localized spectroscopy and imaging....

  20. Tomography by nuclear magnetic resonance

    Imaging methods based on nuclear magnetic resonance allow the production of sectional images of the human body without ionizing radiation. It is possible to measure the density and relaxation times of the water protons in body fluids or tissue. This allows not only to obtain morphological information but also to get some insight into the spatial distribution of physiological data. Starting with a review of the principles of nuclear magnetic resonance it is explained how the measured signal can be associated with an image point; it is also explained what type of apparatus is necessary and what the physical limitations are. Possible risks the patient may be exposed to in an examination using nuclear magnetic resonance are discussed. The present state of the technical development enables the production of whole-body sectional images of a living person within about one minute. By means of some typical examples the nature and properties of these images are explained. Although extensive clinical studies will be necessary before a more general assessment can be made of this method, an outlook is provided on expected further developments and possible future fields of application. (orig.)

  1. Effect of 10B(n, α)7Li irradiation on the structure of a sodium borosilicate glass

    The effects of the nuclear reaction 10B(n, α)7Li on the properties and structure of a sodium borosilicate glass were analysed by density, hardness and fracture toughness measurements, Raman and Nuclear Magnetic Resonance spectroscopy and Transmission Electronic Microscopy (TEM) characterization. The TEM observations showed a homogeneous irradiated glass structure up to the nanometer scale. Modifications of the local order around the main cations were noticed, mainly a slight decrease of the mean boron coordination number and an increase of non-bridging oxygen concentrations. At the glass medium range order, the appearance of the D2 Raman band and a modification of the Si–O–Si angle distribution were also observed after irradiation. A comparison with other irradiation conditions with Swift Heavy Ions (Kr with 74 MeV) and Gold irradiation (with energies ranging from 1 to 7 MeV) is presented. Raman spectroscopy showed a similar final structure for irradiation conditions under which the glass evolutions are controlled by electronic energy loss in the ion tracks formation regime or nuclear energy loss. Despite important differences in energy deposition regimes, the similarities observed between the final glass structures suggest that structural evolutions are controlled by the glass relaxation mechanisms during the high quenching rate step that follows the energy deposition step

  2. An update on the big bang nucleosynthesis prediction for 7Li: the problem worsens

    The lithium problem arises from the significant discrepancy between the primordial 7Li abundance as predicted by big bang nucleosynthesis (BBN) theory and the Wilkinson Microwave Anisotropy Probe (WMAP) baryon density, and the pre-Galactic lithium abundance inferred from observations of metal-poor (Population II) stars. This problem has loomed for the past decade, with a persistent discrepancy of a factor of 2–3 in 7Li/H. Recent developments have sharpened all aspects of the Li problem. Namely: (1) BBN theory predictions have sharpened due to new nuclear data; in particular, the uncertainty on the reaction rate for3He(α,γ)7Be has reduced to 7.4%, nearly a factor of 2 tighter than previous determinations. (2) The WMAP five-year data set now yields a cosmic baryon density with an uncertainty reduced to 2.7%. (3) Observations of metal-poor stars have tested for systematic effects. With these, we now find that the BBN+WMAP predicts7Li/H = (5.24−0.67+0.71) × 10−10. The central value represents an increase by 23%, most of which is due to the upward shift in the3He(α,γ)7Be rate. More significant is the reduction in the7Li/H uncertainty by almost a factor of 2, tracking the reduction in the3He(α,γ)7Be error bar. These changes exacerbate the Li problem; the discrepancy is now a factor 2.4 or 4.2σ (from globular cluster stars) to 4.3 or 5.3σ (from halo field stars). Possible resolutions to the lithium problem are briefly reviewed, and key experimental and astronomical measurements highlighted

  3. The 7Li(γ,N) and 7Li(e,N) reactions at intermediate photon energies

    Cross sections for single-photonucleon emissions from 7Li have been measured for photon energies in the range 60-120 MeV by detecting the recoiling residual nuclei following excitation with bremsstrahlung radiation of end-point energies 140 and 155 MeV. Measurements of the 7Li(e,6Li)e'p and 7Li(e,6He)e'n cross sections were also made at the same electron energies. A significant difference between the ratio of electron- and bremsstrahlung-induced yields for proton and neutron emission is observed. The results are compared to a modified quasi-deuteron model and a simple direct-knockout model in which recoil terms are included. (orig.)

  4. Wide-range nuclear magnetic resonance detector

    Sturman, J. C.; Jirberg, R. J.

    1972-01-01

    Compact and easy to use solid state nuclear magnetic resonance detector is designed for measuring field strength to 20 teslas in cryogenically cooled magnets. Extremely low noise and high sensitivity make detector applicable to nearly all types of analytical nuclear magnetic resonance measurements and can be used in high temperature and radiation environments.

  5. Li mobility in Nasicon-type materials LiM2(PO4)3, M = Ge, Ti, Sn, Zr and Hf, followed by 7Li NMR spectroscopy.

    Arbi, K; París, M A; Sanz, J

    2011-10-21

    Lithium mobility in LiM(2)(PO(4))(3) compounds, M = Ge and Sn, has been investigated by (7)Li Nuclear Magnetic Resonance (NMR) spectroscopy, and deduced information compared with that reported previously in Ti, Zr and Hf members of the series in the temperature range 100-500 K. From the analysis of (7)Li NMR quadrupole interactions (C(Q) and η parameters), spin-spin T(2)(-1) and spin-lattice T(1)(-1) relaxation rates, structural sites occupancy and mobility of lithium have been deduced. Below 250 K, Li ions are preferentially located at M(1) sites in rhombohedral phases, but occupy intermediate M(12) sites between M(1) and M(2) sites in triclinic ones. In high-temperature rhombohedral phases, a superionic state is achieved when residence times at M(1) and M(12) sites become similar and correlation effects on Li motion decrease. This state can be obtained by large order-disorder transformations in rhombohedral phases or by sharp first order transitions in triclinic ones. The presence of two relaxation mechanisms in T(1)(-1) plots of rhombohedral phases has been associated with departures of conductivity from the Arrhenius behavior. Long term mobility of lithium is discussed in terms of the cation vacancy distribution along conduction paths. PMID:21897945

  6. Evanescent Waves Nuclear Magnetic Resonance.

    Halidi, El Mohamed; Nativel, Eric; Akel, Mohamad; Kenouche, Samir; Coillot, Christophe; Alibert, Eric; Jabakhanji, Bilal; Schimpf, Remy; Zanca, Michel; Stein, Paul; Goze-Bac, Christophe

    2016-01-01

    Nuclear Magnetic Resonance spectroscopy and imaging can be classified as inductive techniques working in the near- to far-field regimes. We investigate an alternative capacitive detection with the use of micrometer sized probes positioned at sub wavelength distances of the sample in order to characterize and model evanescent electromagnetic fields originating from NMR phenomenon. We report that in this experimental configuration the available NMR signal is one order of magnitude larger and follows an exponential decay inversely proportional to the size of the emitters. Those investigations open a new road to a better understanding of the evanescent waves component in NMR with the opportunity to perform localized spectroscopy and imaging. PMID:26751800

  7. Nuclear magnetic ordering in silver

    Nuclear antiferromagnetic ordering has been observed by neutron diffraction in a single crystal of 109Ag. The critical temperature is found to 700 pK, and the critical field is 100 μT. From the paramagnetic phase a second order phase transition leads into a type-I 1-k structure with long range order. The experiments have taken place at the Hahn-Meitner Institut in Berlin in collaboration with the low Temperature Laboratory in Helsinki, the Niels Bohr Institute in Copenhagen, and Risoe National Laboratory, Roskilde. The present report is a Ph.D. thesis which has been successfully defended at the Niels Bohr Institute. Besides the results of the nuclear ordering experiments the thesis contains a description of the theoretical background for nuclear magnetism and a review of earlier nuclear ordering experiments as well as theoretical work. The principles for studying polarized nuclei with use of polarized and unpolarized neutrons are presented, as well as the results of such experiments. (au) 11 tabs., 59 ills., 143 refs

  8. Nuclear magnetic ordering in silver

    Lefmann, K.

    1995-12-01

    Nuclear antiferromagnetic ordering has been observed by neutron diffraction in a single crystal of {sup 109}Ag. The critical temperature is found to 700 pK, and the critical field is 100 {mu}T. From the paramagnetic phase a second order phase transition leads into a type-I 1-k structure with long range order. The experiments have taken place at the Hahn-Meitner Institut in Berlin in collaboration with the low Temperature Laboratory in Helsinki, the Niels Bohr Institute in Copenhagen, and Risoe National Laboratory, Roskilde. The present report is a Ph.D. thesis which has been successfully defended at the Niels Bohr Institute. Besides the results of the nuclear ordering experiments the thesis contains a description of the theoretical background for nuclear magnetism and a review of earlier nuclear ordering experiments as well as theoretical work. The principles for studying polarized nuclei with use of polarized and unpolarized neutrons are presented, as well as the results of such experiments. (au) 11 tabs., 59 ills., 143 refs.

  9. Developments in quantum information processing by nuclear magnetic resonance: Use of quadrupolar and dipolar couplings

    Anil Kumar; K V Ramanathan; T S Mahesh; Neeraj Sinha; K V R Murali

    2002-08-01

    Use of dipolar and quadrupolar couplings for quantum information processing (QIP) by nuclear magnetic resonance (NMR) is described. In these cases, instead of the individual spins being qubits, the 2 energy levels of the spin-system can be treated as an -qubit system. It is demonstrated that QIP in such systems can be carried out using transition-selective pulses, in CH3CN, 13CH3CN, 7Li ( = 3/2) and 133Cs ( = 7/2), oriented in liquid crystals yielding 2 and 3 qubit systems. Creation of pseudopure states, implementation of logic gates and arithmetic operations (half-adder and subtractor) have been carried out in these systems using transition-selective pulses.

  10. Protein dynamics from nuclear magnetic relaxation.

    Charlier, Cyril; Cousin, Samuel F; Ferrage, Fabien

    2016-05-01

    Nuclear magnetic resonance is a ubiquitous spectroscopic tool to explore molecules with atomic resolution. Nuclear magnetic relaxation is intimately connected to molecular motions. Many methods and models have been developed to measure and interpret the characteristic rates of nuclear magnetic relaxation in proteins. These approaches shed light on a rich and diverse range of motions covering timescales from picoseconds to seconds. Here, we introduce some of the basic concepts upon which these approaches are built and provide a series of illustrations. PMID:26932314

  11. Nuclear magnetic resonance studies of erythrocyte membranes

    Chapman, D.; Kamat, V.B.; Gier, J. de; Penkett, S.A.

    1968-01-01

    The use of nuclear magnetic resonance spectroscopy for studying molecular interactions in biological membranes has been investigated using erythrocyte membrane fragments. Sonic dispersion of these fragments produces a sharp and well-defined high-resolution nuclear magnetic resonance spectrum. The sp

  12. Non-thermal processes in standard big bang nucleosynthesis: II. Two-body disintegration of D, 7Li, 7Be nuclei by fast neutrons

    Continuing the analysis of non-thermal effects in standard big bang nucleosynthesis (JCAP05(2008)010), we examine the role of suprathermal nuclear reactions induced in the early universe plasma by energetic nucleons of various origins. The processes of present interest are break-ups of D, 7Li, 7Be nuclei induced by 14-MeV neutrons generated in the plasma via the T(d, n)4He reaction. It is shown that this reaction forms the ensemble of fast neutrons whose fraction in the plasma neutron component is at the level of 0.01 %. In spite of the small percentage, such neutrons can effectively destroy the loosely bound D, 7Li, 7Be nuclei. It is found that at temperatures T9 7Li dominate over other reactions occurring in the n+D and n+7Li systems. However, the non-thermal neutronic effects prove to be insufficiently strong to modify the standard picture of nucleosynthesis. The D, 3He, 4He abundances are obtained to remain unchanged, and only a little effect is marked for primordial 7Li. The 0.01 % fraction of plasma neutrons (fast DT neutrons) reduces the 7Li abundance by 0.02 %

  13. Contribution to nuclear magnetic resonance imager using permanent magnets

    After some recalls of nuclear magnetic resonance, ways to get a stable and homogeneous magnetic field are studied with permanent magnets. Development of correction coils on integrated circuits has been particularly stressed. Gradient coil specific systems have been studied taking in account ferromagnetic material presence. Antenna system has been improved and possibility of image obtention with the prototype realized has been shown

  14. Nuclear reactions in ultra-magnetized supernovae

    The statistical model is employed to investigate nuclear reactions in ultrastrong magnetic fields relevant for supernovae and neutron stars. For radiative capture processes the predominant mechanisms are argued to correspond to modifications of nuclear level densities, and γ-transition energies due to interactions of the field with magnetic moments of nuclei. The density of states reflects the nuclear structure and results in oscillations of reaction cross sections as a function of field strength, while magnetic interaction energy enhances radiative neutron capture process. Implications in the synthesis of r-process nuclei in supernova site are discussed. (author)

  15. Nuclear magnetic (ratio-frequency) tomography

    Physical foundations of nuclear magnetic tomography and factors limiting its spatial, contrast and time precision are considered. On the basis of analysis of literature data, it is established that using peculiarities of nuclear magnetic resonance (NMR) it is possible to detect malignant tumors and edemas, to investigate metabolic processes, to determine blood flow rate and to solve a number of other problems. The classification of methods of NMR - tomography is given

  16. Nuclear magnetic (radio-frequency) tomography

    Pavlov, A.S.; Gurvich, A.M.; Karyakina, N.F.; Revokatov, O.P.; Chikirdin, Eh.G. (Nauchno-Issledovatel' skij Inst. Rentgenologii i Radiologii, Moscow (USSR))

    Physical foundations of nuclear magnetic tomography and factors limiting its spatial, contrast and time precision are considered. On the basis of analysis of literature data, it is established that using peculiarities of nuclear magnetic resonance (NMR) it is possible to detect malignant tumors and edemas, to investigate metabolic processes, to determine blood flow rate and to solve a number of other problems. The classification of methods of NMR - tomography is given.

  17. Nuclear Magnetic Resonance Imaging: Current Capabilities

    Davis, Peter L.; Crooks, Lawrence E.; Margulis, Alexander R.; Kaufman, Leon

    1982-01-01

    Nuclear magnetic resonance imaging can produce tomographic images of the body without ionizing radiation. Images of the head, chest, abdomen, pelvis and extremities have been obtained and normal structures and pathology have been identified. Soft tissue contrast with this method is superior to that with x-ray computerized tomography and its spatial resolution is approaching that of x-ray computerized tomography. In addition, nuclear magnetic resonance imaging enables us to image along the sag...

  18. Experiments on iron shield transmission of quasi-monoenergetic neutrons generated by 43- and 68-MeV protons via the {sup 7}Li(p,n) reaction

    Nakashima, Hiroshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Tanaka, Shun-ichi; Nakao, Noriaki [and others

    1996-03-01

    In order to provide benchmark data of neutrons transmitted through iron shields in the intermediate-energy region, spatial distributions of neutron energy spectra and reaction rates behind and inside the iron shields of thickness up to 130 cm were measured for 43- and 68-MeVp-{sup 7}Li neutrons using a quasi-monoenergetic neutron beam source at the 90-MV AVF cyclotron facility of the TLARA facility in JAERI. The measured data by five kinds of detectors: the BC501A detector, the Bonner ball counter, {sup 238}U and {sup 232}Th fission counters, {sup 7}LiF and {sup nat}LiF TLDs and solid state nuclear track detector, are numerically provided in this report in the energy region between 10{sup -4} eV and the energy of peak neutrons generated by the {sup 7}Li(p,n) reaction. (author).

  19. Experiments on iron shield transmission of quasi-monoenergetic neutrons generated by 43- and 68-MeV protons via the 7Li(p,n) reaction

    In order to provide benchmark data of neutrons transmitted through iron shields in the intermediate-energy region, spatial distributions of neutron energy spectra and reaction rates behind and inside the iron shields of thickness up to 130 cm were measured for 43- and 68-MeVp-7Li neutrons using a quasi-monoenergetic neutron beam source at the 90-MV AVF cyclotron facility of the TLARA facility in JAERI. The measured data by five kinds of detectors: the BC501A detector, the Bonner ball counter, 238U and 232Th fission counters, 7LiF and natLiF TLDs and solid state nuclear track detector, are numerically provided in this report in the energy region between 10-4 eV and the energy of peak neutrons generated by the 7Li(p,n) reaction. (author)

  20. Generation of nuclear magnetic resonance images

    Two generation techniques of nuclear magnetic resonance images, the retro-projection and the direct transformation method are studied these techniques are based on the acquisition of NMR signals which phases and frequency components are codified in space by application of magnetic field gradients. The construction of magnet coils is discussed, in particular a suitable magnet geometry with polar pieces and air gap. The obtention of image contrast by T1 and T2 relaxation times reconstructed from generated signals using sequences such as spin-echo, inversion-recovery and stimulated echo, is discussed. The mathematical formalism of matrix solution for Bloch equations is also presented. (M.C.K.)

  1. Nuclear magnetic resonance (NMR): principles and applications

    The basis for the phenomenon of nuclear magnetic resonance (NMR) is the ability of certain nuclei possessing both intrinsic angular momentum or ''spin'' I and magnetic moment to absorb electromagnetic energy in the radio frequency range. In principle, there are approximately 200 nuclei which may be investigated using the NMR technique. The NMR spectrum consists of intensity peaks along an axis calibrated in terms of the steady magnetic field or the frequency of the radiofrequency electromagnetic radiation. Analysis of the number, spacing, position and intensity of the lines in an NMR spectrum consists of intensity peaks along an axis calibrated in terms of the steady magnetic field or the frequency of the radiofrequency electromagnetic radiation. Analysis of the number, spacing, position and intensity of the lines in an NMR spectrum provides a variety of qualitative and quantitative analytical applications. The most obvious applications consist of the measurements of nuclear properties, such as spin number and nuclear magnetic moment. In liquids, the fine structure of resonance spectra provides a tool for chemical identification and molecular structure analysis. Other applications include the measurements of self-diffusion coefficients, magnetic fields and field homogeneity, inter-nuclear distances, and, in some cases, the water content of biological materials. (author)

  2. Theory of nuclear magnetic moments - LT-35

    The purpose of these notes is to give an account of some attempts at interpreting the observed values of nuclear magnetic moments. There is no attempt at a complete summary of the field as that would take much more space than is used here. In many cases the arguments are only outlined and references are given for those interested in further details. A discussion of the theory of nuclear magnetic moments necessitates many excursions into the details of the nuclear models because the magnetic moments have a direct bearing on the validity of these models. However the main emphasis here is on those features which tend to explain the magnetic moments and other evidence is not discussed unless it has a direct bearing on the problem. In the first part of the discussion the Shell Model of the nucleus is used, as this model seems to correlate a large body of data relating to the heavier nuclei. Included here are the modifications proposed to explain the fact that the experimental magnetic moments do not fit quantitatively with the exact predictions of the Shell Model. The next sections deal with some of the more drastic modifications introduced to explain the large nuclear quadrupole moments and the effect of these modifications on the magnetic moments. Finally we turn to more detailed investigations of the light nuclei, in particular the - Conjugate nuclei. (author)

  3. Detection of the inverse pion electroproduction on 7Li nuclei

    The inverse pion electroproduction process on 7Li nucleus, π++7Li→e++e-+X, at the pion kinetic energy of 380 MeV has been detected. The missing mass distribution of the process events is described well assuming that approximately one half of the detected events belongs to the reaction channel producing 7Be nucleus either in the ground state (7Be) or in the excited state (7Be*): π++7Li→e++e-+7Be(7Be*). For this reaction the differential cross section for the electron and positron energies above 70 MeV, for the particles emitted under an angle of about 65 deg in l. s., is d2σ/dΩ2=(1.3+-0.3)x10-32 cm2/sr2

  4. Pulsed nuclear-electronic magnetic resonance

    Morley, Gavin W; Mohammady, M Hamed; Aeppli, Gabriel; Kay, Christopher W M; Jeschke, Gunnar; Monteiro, Tania S

    2011-01-01

    Pulsed magnetic resonance is a wide-reaching technology allowing the quantum state of electronic and nuclear spins to be controlled on the timescale of nanoseconds and microseconds respectively. The time required to flip either dilute electronic or nuclear spins is orders of magnitude shorter than their decoherence times, leading to several schemes for quantum information processing with spin qubits. We investigate instead the novel regime where the eigenstates approximate 50:50 superpositions of the electronic and nuclear spin states forming "nuclear-electronic" qubits. Here we demonstrate quantum control of these states, using bismuth-doped silicon, in just 32 ns: orders of magnitude shorter than previous experiments where pure nuclear states were used. The coherence times of our states are over four orders of magnitude longer, being 1 ms or more at 8 K, and are limited by the naturally-occurring 29Si nuclear spin impurities. There is quantitative agreement between our experiments and no-free-parameter anal...

  5. Progress in nuclear magnetic resonance spectroscopy

    Emsley, J W; Sutcliffe, L H

    2013-01-01

    Progress in Nuclear Magnetic Resonance Spectroscopy, Part 1 is a two-chapter text that reviews significant developments in nuclear magnetic resonance (NMR) applications.The first chapter discusses NMR studies of molecules physisorbed on homogeneous surfaces. This chapter also describes the phase changes in the adsorbed layer detected by following the variation in the NMR parameters. The second chapter examines the process to obtain a plotted, data reduced Fourier transform NMR spectrum. This chapter highlights the pitfalls that can cause a decrease in information content in a NMR spectrum. The

  6. Nuclear magnetic resonance of thermally oriented nuclei

    The more recent developments in the spectroscopy of Nuclear Magnetic Resonance on Oriented Nuclei (NMRON) are reviewed; both theoretical and experimental advances are summarised with applications to On-Line and Off-Line determination of magnetic dipole and electric quadrupole hyperfine parameters. Some emphasis is provided on solid state considerations with indications of where likely enhancements in technique will lead in conventional hyperfine studies. (orig.)

  7. Nuclear magnetic resonance in Kondo lattice systems

    Curro, Nicholas J.

    2016-06-01

    Nuclear magnetic resonance has emerged as a vital tool to explore the fundamental physics of Kondo lattice systems. Because nuclear spins experience two different hyperfine couplings to the itinerant conduction electrons and to the local f moments, the Knight shift can probe multiple types of spin correlations that are not accessible via other techniques. The Knight shift provides direct information about the onset of heavy electron coherence and the emergence of the heavy electron fluid.

  8. magnetic order studied by nuclear methods

    Reichl, C

    2001-01-01

    investigated within the frame of this work. The studies on the highly concentrated deuterides revealed a gradual loss in local field due to a distribution of 'local Curie temperatures' depending on the number of Fe neighbours and their distances from the Moessbauer nucleus. On rising the temperature, during a magnetic transition, an increasing number of Fe sites with different local environment loose their hyperfine fields, whereas bulk measurements showed a relatively sharp, however, incomplete transition. By using a combination of neutron diffraction- and muon spin relaxation studies the complex magnetic phase diagram of the system Ce(Rh,Ru) sub 3 B sub 2 , where weak magnetic moments exist, could be studied. There, transitions from para- to ferromagnetism, and more complicated magnetic structures could be observed. Due to the existence of several isotopes of B and Ru, each carrying different nuclear spins and magnetic moment, particularly complicated second moment simulations for interpreting the muon data...

  9. Phosphonate Based High Nuclearity Magnetic Cages.

    Sheikh, Javeed Ahmad; Jena, Himanshu Sekhar; Clearfield, Abraham; Konar, Sanjit

    2016-06-21

    Transition metal based high nuclearity molecular magnetic cages are a very important class of compounds owing to their potential applications in fabricating new generation molecular magnets such as single molecular magnets, magnetic refrigerants, etc. Most of the reported polynuclear cages contain carboxylates or alkoxides as ligands. However, the binding ability of phosphonates with transition metal ions is stronger than the carboxylates or alkoxides. The presence of three oxygen donor sites enables phosphonates to bridge up to nine metal centers simultaneously. But very few phosphonate based transition metal cages were reported in the literature until recently, mainly because of synthetic difficulties, propensity to result in layered compounds, and also their poor crystalline properties. Accordingly, various synthetic strategies have been followed by several groups in order to overcome such synthetic difficulties. These strategies mainly include use of small preformed metal precursors, proper choice of coligands along with the phosphonate ligands, and use of sterically hindered bulky phosphonate ligands. Currently, the phosphonate system offers a library of high nuclearity transition metal and mixed metal (3d-4f) cages with aesthetically pleasing structures and interesting magnetic properties. This Account is in the form of a research landscape on our efforts to synthesize and characterize new types of phosphonate based high nuclearity paramagnetic transition metal cages. We quite often experienced synthetic difficulties with such versatile systems in assembling high nuclearity metal cages. Few methods have been emphasized for the self-assembly of phosphonate systems with suitable transition metal ions in achieving high nuclearity. We highlighted our journey from 2005 until today for phosphonate based high nuclearity transition metal cages with V(IV/V), Mn(II/III), Fe(III), Co(II), Ni(II), and Cu(II) metal ions and their magnetic properties. We observed that

  10. Prospects of lithium enrichment on 7Li isotope by method of controlled ions electro-migration

    Martoyan, G. A.; Kalugin, M. M.; Gabrielyan, A. V.; Martoyan, A. G.

    2016-01-01

    This paper deals with a new electro-membrane method of enrichment of 7Li isotope. The data are presented on the importance and application fields regarding the use of 7Li isotopes. Existing methods and criteria of separation of lithium isotopes are discussed. The principle of new technology, regimes of enrichment experiments, and analysis details of obtained products are briefly described.

  11. Fission fragment mass and angular distribution in 6,7Li+235,238U reactions

    Fission fragment (FF) angular distributions for 6,7Li+235,238U reactions and mass distributions for 6,7Li+ 238U reactions have been measured at energies near and above the Coulomb barrier. The angle integrated fission cross sections for 6Li induced reactions at sub-barrier energies are found to be higher than 7Li induced reactions possibly due to larger contribution of breakup induced fission in case of the former compared to the latter. The FF anisotropy for 6,7Li+235U was found to be smaller than 6,7Li+238U, manifesting the effect of target ground state spin. The statistical saddle point (SSP) model predictions were found to be consistent with the measured FF anisotropy for 6,7Li+235U, however they were under-estimated for 6,7Li+238U particularly at lower energies. Observation of larger FWHM of FF folding angle distribution and sharp increase in peak to valley ratio for FF mass distribution with the decrease in bombarding energy in 6,7Li+238U reactions confirms the presence of breakup induced fission. (authors)

  12. Fission fragment mass and angular distribution in 6,7Li+235,238U reactions

    Santra S.

    2013-12-01

    Full Text Available Fission fragment (FF angular distributions for 6,7Li+235,238U reactions and mass distributions for 6,7Li+238U reactions have been measured at energies near and above the Coulomb barrier. The angle integrated fission cross sections for 6Li induced reactions at sub-barrier energies are found to be higher than 7Li induced reactions possibly due to larger contribution of breakup induced fission in case of the former compared to the latter. The FF anisotropy for 6,7Li+235U was found to be smaller than 6,7Li+238U, manifesting the effect of target ground state spin. The statistical saddle point (SSP model predictions were found to be consistent with the measured FF anisotropy for 6,7Li+235U, however they were under-estimated for 6,7Li+238U particularly at lower energies. Observation of larger FWHM of FF folding angle distribution and sharp increase in peak to valley ratio for FF mass distribution with the decrease in bombarding energy in 6,7Li+238U reactions confirms the presence of breakup induced fission.

  13. Use of 7Li(p,n) reaction as a neutron source in a PGNAA setup.

    Naqvi, A A; Nagadi, M M

    2005-03-01

    The performance of a 7Li(p,n) reaction-based Prompt Gamma Ray Neutron Activation Analysis (PGNAA) setup has been determined for analysis of Portland cement samples using Monte Carlo study. The calculations were carried out for a 7Li(p,n) reaction-based PGNAA setup with an external moderator similar to the one used in a previous 2.8 MeV neutrons-based PGNAA setup. The optimum values of geometry parameters of the 7Li(p,n) reaction-based setup are different from those of the 2.8 MeV neutrons-based setup resulting in better performance of the 7Li(p,n) reaction-based setup. The prompt gamma-ray yield from the 7Li(p,n) reaction-based setup is 60-70% higher than that from the 2.8 MeV neutrons-based setup. Although the performances of the 7Li(p,n) reaction-based setup is comparable with that of a previously studied 3H(p,n) reaction-based setup, yet performance of the 7Li(p,n) reaction-based setup is superior to that of the 3H(p,n) reaction-based setup because it has less radiation hazard due to utilization of non-radioactive neutron producing target. This study has provided a theoretical base for experimental test of a 7Li(p,n) reaction-based PGNAA setup. PMID:15607917

  14. Use of 7Li(p,n) reaction as a neutron source in a PGNAA setup

    The performance of a 7Li(p,n) reaction-based Prompt Gamma Ray Neutron Activation Analysis (PGNAA) setup has been determined for analysis of Portland cement samples using Monte Carlo study. The calculations were carried out for a 7Li(p,n) reaction-based PGNAA setup with an external moderator similar to the one used in a previous 2.8 MeV neutrons-based PGNAA setup. The optimum values of geometry parameters of the 7Li(p,n) reaction-based setup are different from those of the 2.8 MeV neutrons-based setup resulting in better performance of the 7Li(p,n) reaction-based setup. The prompt γ-ray yield from the 7Li(p,n) reaction-based setup is 60-70% higher than that from the 2.8 MeV neutrons-based setup. Although the performances of the 7Li(p,n) reaction-based setup is comparable with that of a previously studied 3H(p,n) reaction-based setup, yet performance of the 7Li(p,n) reaction-based setup is superior to that of the 3H(p,n) reaction-based setup because it has less radiation hazard due to utilization of non-radioactive neutron producing target. This study has provided a theoretical base for experimental test of a 7Li(p,n) reaction-based PGNAA setup

  15. Study of fusion barrier distribution from quasielastic scattering for 6,7Li + 197Au systems

    Earlier we have reported breakup and fusion excitation function measurements in 6,7Li + 197Au systems. In this paper we present the fusion barrier distribution from QEL at backward angles for the same systems, namely, 6,7Li + 197Au

  16. Excitation and decay of 7Li*(4.63) → α + t in the 7Li(αα1)7Li(4.63) and 9Be(dα1)7Li(4.63) reactions in close kinematic conditions

    Angular correlation function (ACF) of alpha particles and tritons from 7Li* (4.63) decay in the d+9Be → α1+7Li*(4.63) → α1+t+α reaction at deuteron energy Ed=13.6 MeV for escape angles Θαlab=45 and 67 deg has been measured. Results of investigation into the α+7Li → α1+7Li*(4.63) → α1+t+d reaction at Eα=27.2 MeV, Θα1lab=30 deg have been used as well. Kinematic conditions for outlet channels of both reactions are identical. An analytical expression for ACF has been derived. The analysis shows that different mechanisms of the first stage of the d+9Be and α+7Li reactions result in differential phase shifts and limits of summing in the formula for ACF and, therefore, in different ACF form

  17. Thin layer and nuclear magnetic resonance magnetometers

    In the first part of this text, magnetometers with sensitive elements in the form of thin cylindrical ferromagnetic layers are described. These layers are anisotropic, uniaxial, C orientated and single domains. In the second part of the text, the principles of the nuclear magnetic resonance magnetometer realized at the LETI are presented. This instrument is accurate, of high efficiency, and isotropic. Very small variations in magnetic field intensity (10-7 oersteds) can be detected with a 1Hz pass band at zero frequency

  18. Nuclear magnetic resonance as a petrophysical measurement

    Nuclear magnetic resonance (NMR) of hydrogen nuclei in fluids which saturate porous rocks is important in oil exploration and production, since NMR logs can provide good estimates of permeability and fluid flow. This paper reviews developments which connect the NMR properties of rocks with petrophysical properties, and particularly those relating to fluid flow. The recent advances in the use of NMR in boreholes which have spurred these developments are also discussed. The relevance of other NMR measurements on geological samples, including magnetic resonance imaging, is briefly referred to. (author)

  19. Nuclear magnetic ordering ''avant toute chose''

    We give an overview of the research initiated at Saclay to study cooperative phenomena between nuclear spins in the presence of a high magnetic field. These systems exhibit a wealth of different orderings including antiferromagnetism, ferromagnetism with domains and transverse structures rotating about the static magnetic field. These states have been characterized by NMR of the ordered nuclei, NMR of dilute probe nuclei, double resonance methods and neutron diffraction. Some related phenomena involving the coupling of spins with the lattice are reported. Finally we outline future experiments which will benefit of the insight brought by the study of dipolar ordering. (authors). 30 refs., 11 figs

  20. The 3He(alpha, gamma)7Be reaction rate, solar 7Be and 8B neutrino fluxes, and the production of 7Li during the Big Bang

    The 3He(α,γ)7Be reaction plays an important role both in determining the predicted fluxes of 7Be and 8B neutrinos from our Sun, and in the calculation of primordial 7Li production. In light of the highly precise determination of the baryon-to-photon ratio from the cosmic microwave background data, it is necessary to re-determine primordial 7Li production. Recent experimental nuclear astrophysics work has led to an improved determination of the 3He(α,γ)7Be cross section, with several experiments clustered at E = 0.5 MeV center-of-mass energy and above [2, and references therein]. On the other hand, precisely calibrated 7Be and 8B neutrino fluxes from the Sun are now available. Assuming the accepted solar central temperature to be correct, the neutrino flux data can be used to determine the 3He(α,γ)7Be cross section at the solar Gamow peak, E = 0.03 MeV. The energy range relevant for Big Bang 7Li production lies just between 0.03 and 0.5 MeV. The poster aims to use the two above described levels in order to improve the precision of the predicted primordial abundance of 7Li. It updates a previous work that appeared before the new cross section, solar neutrino and microwave background data were available. (author)

  1. Coherent photoproduction of π0- and η-mesons off 7Li

    Coherent photoproduction of π0-mesons from threshold (Eth ∼ 136 MeV) throughout the Δ-resonance region and of η-mesons close to the production threshold (Eth ∼ 570 MeV) for η has been measured for 7Li nuclei. The experiment was performed using the tagged-photon beam of the Mainz MAMI accelerator with the Crystal Ball and TAPS detectors combined to give an almost 4 π solid-angle electromagnetic calorimeter. The reactions were identified by a combined invariant-mass and missing-energy analysis. A comparison of the pion data to plane-wave impulse modelling tests the nuclear mass form factor. So far coherent η production had been only identified for the lightest nuclear systems (2H and 3He). For 3He a large enhancement of the cross section above plane-wave approximations had been reported, indicating the formation of a quasi-bound state. The present Li data for η production agree with a plane-wave approximation. Contrary to 3He, neither a threshold enhancement of the total cross section nor a deviation of the angular distributions from the expected form factor dependence were observed. (orig.)

  2. Structural nature of 7Li and 11B sites in the nonlinear optical material LiB3O5 using static NMR and MAS NMR

    The structural nature of the nonlinear optical properties of LiB3O5 is analyzed using single-crystal nuclear magnetic resonance (NMR) and magic angle spinning (MAS) NMR. The 3-coordinated trigonal [B(1) and B(2)] and 4-coordinated tetragonal [B(3)] sites are distinguished using the spectrum and the spin-lattice relaxation time in rotating frame T1ρ, which was obtained from the 11B MAS NMR. Moreover, the T1 and T1ρ values for 7Li and 11B are compared, and the activation energies were obtained. The T1ρ values of the boron nuclei in LiB3O5 show no significant changes. These results may be closely related to the largest second-order nonlinear optical coefficient. - Highlights: • The structural nature of the nonlinear optical properties of LiB3O5. • Single-crystal NMR and MAS NMR. • The 3-coordnated trigonal and 4-coordinated tetragonal. • The spin-lattice relaxation time in rotating frame T1ρ

  3. Experimental test of nuclear magnetization distribution and nuclear structure models

    Models exist that ascribe the nuclear magnetic fields to the presence of a single nucleon whose spin is not neutralized by pairing it up with that of another nucleon; other models assume that the generation of the magnetic field is shared among some or all nucleons throughout the nucleus. All models predict the same magnetic field external to the nucleus since this is an anchor provided by experiments. The models differ, however, in their predictions of the magnetic field arrangement within the nucleus for which no data exist. The only way to distinguish which model gives the correct description of the nucleus would be to use a probe inserted into the nucleus. The goal of our project was to develop exactly such a probe and to use it to measure fundamental nuclear quantities that have eluded experimental scrutiny. The need for accurately knowing such quantities extends far beyond nuclear physics and has ramifications in parity violation experiments on atomic traps and the testing of the standard model in elementary particle physics. Unlike scattering experiments that employ streams of free particles, our technique to probe the internal magnetic field distribution of the nucleus rests on using a single bound electron. Quantum mechanics shows that an electron in the innermost orbital surrounding the nucleus constantly dives into the nucleus and thus samples the fields that exist inside. This sampling of the nucleus usually results in only minute shifts in the electron s average orbital, which would be difficult to detect. By studying two particular energy states of the electron, we can, however, dramatically enhance the effects of the distribution of the magnetic fields in the nucleus. In fact about 2% of the energy difference between the two states, dubbed the hyperfine splitting, is determined by the effects related to the distribution of magnetic fields in the nucleus, A precise measurement of this energy difference (better than 0.01%) would then allow us to place

  4. Nuclear magnetic moments measured by nuclear magnetic resonance on oriented nuclei

    The configurations of nuclei near the shell closures N=40 and Z=40 were studied. The nuclear magnetic moments have been measured by nuclear magnetic resonance on oriented nuclei (NMR/ON). We have determined the ground state spin of 73Se and magnetic moments of isotopes 73Se(9/2+), 77Br3/2-) and 74Brm(4). The 9/2+ spin and parity assignment to the parent state of 73Se is perfectly compatible with the systematics of N + 39 and N = 41 isotones. The bromine moments around the shell closure N = 40, show a change in protonic configuration. In the second part of this work a precise hyperfine field value of zinc in iron has been determined. The relaxation constant of Zn in iron is established. The new hyperfine field value of zinc in iron allows a more precise reevaluation of the magnetic moments of 69Znm and 71Znm measured with NMR/ON

  5. Elastic scattering of vector polarized 7LiON58Ni

    The elastic scattering of vector polarized 7Li on 58Ni at 20.3 MeV exhibits vector analyzing powers of approximate the same size but of opposite sign as the ones observed for elastic 6Li-58Ni scattering. Present versions of the folding model predict that vector analyzing powers for 7Li should have the same much smaller magnitude than for 6Li scattering. The physical reasons of this observed effect are presently not known. (orig.)

  6. Importance of the tensor interaction in the (/sup 7/Li, /sup 7/Be) reaction

    Dodd, A.C.; Clarke, N.M.; Coopersmith, J.; Griffiths, R.J.; Pearce, K.I.; Stanley, B.; Cook, J.

    1985-09-01

    Data for the /sup 28/Si(/sup 7/Li, /sup 7/Be)/sup 28/Al reaction at 72 MeV and for the /sup 26/Mg(/sup 7/Li, /sup 7/Be)/sup 26/Na reaction at 88 MeV are presented together with one-step DWBA calculations using microscopic form factors. The tensor interaction is shown to be important to explain the structureless nature of the angular distributions.

  7. The importance of the tensor interaction in the (7Li, 7Be) reaction

    Data for the 28Si(7Li, 7Be)28Al reaction at 72 MeV and for the 26Mg(7Li, 7Be)26Na reaction at 88 MeV are presented together with one-step DWBA calculations using microscopic form factors. The tensor interaction is shown to be important to explain the structureless nature of the angular distributions. (author)

  8. Investigation of 7Li(n, γ)8Li reaction by law energy

    The wave functions and main spectroscopic characteristics of the 8Li nucleus as well as the interaction potential in the 7Li+n channel are calculated within the frames of the three-body αtn-potential cluster model. The complete cross sections and reaction velocities of the 7Li(n, γ)8Li are determined along with the above values in the area of the energy up to 1 MeV

  9. Lines in the spectrum of 7LiH (4728--5298 A)

    The emission spectra of the A1Σ+--X1Σ+ bands of 7LiH were photographed in the 4728A - 5298 A region with a 3.4 meter Ebert Spectrograph of theoretical resolution of about 0.07 cm-1. High purity 7LiH crystals were obtained from Oak Ridge National Laboratory. The atomic percent of 7Li in 7LiH and 7LiD was 99.93 percent. The discharge source was a demountable stainless steel hollow cathode lamp. The lithium hydride crystals were packed into the cathode. Pressure in the discharge tube was about 10 to 20 torr of H2. The discharge was run at about 600 volts and 1.25 to 1.75 amperes. Acceptable spectra were obtained with exposure time of 6 hours. A Westinghouse iron hollow cathode was used to produce the iron spectrum for calibration. The plates were measured on the Gaertner photoplate comparator with an encoder system and on-line computer service at Argonne National Laboratory. The measured lines in the spectra of 7LiH are given in this repot 9COO-2326-19). Similar spectra for 6LiH and 6LiD are given in companion reports (COO-2326-17) and (COO-2326-18), respectively. The relative intensities of the lines are applicable only to short regions and do not extend over the whole spectrum

  10. Solid state nuclear magnetic resonance investigations of advanced energy materials

    Bennett, George D.

    In order to better understand the physical electrochemical changes that take place in lithium ion batteries and asymmetric hybrid supercapacitors solid state nuclear magnetic resonance (NMR) spectroscopy has been useful to probe and identify changes on the atomic and molecular level. NMR is used to characterize the local environment and investigate the dynamical properties of materials used in electrochemical storage devices (ESD). NMR investigations was used to better understand the chemical composition of the solid electrolyte interphase which form on the negative and positive electrodes of lithium batteries as well as identify the breakdown products that occur in the operation of the asymmetric hybrid supercapacitors. The use of nano-structured particles in the development of new materials causes changes in the electrical, structural and other material properties. NMR was used to investigate the affects of fluorinated and non fluorinated single wall nanotubes (SWNT). In this thesis three experiments were performed using solid state NMR samples to better characterize them. The electrochemical reactions of a lithium ion battery determine its operational profile. Numerous means have been employed to enhance battery cycle life and operating temperature range. One primary means is the choice and makeup of the electrolyte. This study focuses on the characteristics of the solid electrolyte interphase (SEI) that is formed on the electrodes surface during the charge discharge cycle. The electrolyte in this study was altered with several additives in order to determine the influence of the additives on SEI formation as well as the intercalation and de-intercalation of lithium ions in the electrodes. 7Li NMR studies where used to characterize the SEI and its composition. Solid state NMR studies of the carbon enriched acetonitrile electrolyte in a nonaqueous asymmetric hybrid supercapacitor were performed. Magic angle spinning (MAS) coupled with cross polarization NMR

  11. Search for solar axions emitted in the M1-transition of 7Li* with Borexino CTF

    Results of background measurements with a prototype of the Borexino detector were used to search for 478 keV solar axions emitted in the M1-transitions of 7Li*. The Compton conversion of axion to a photon A+e→e+γ, axioelectric effect A+e+Z→e+Z, decay of axion in two photons A→2γ and Primakoff conversion on nuclei A+Z→γ+Z are considered. The upper limit on constants of interaction of axion with electrons, photons and nucleons -gAegAN≤(1.0-2.4) x 10-10 at mA≤450 keV and gAγgAN≤5 x 10-9 GeV-1 at mA≤10 keV are obtained (90%c.l.). For heavy axions with mass at 100AAe-8 and gAγ-9-10-8 are obtained in assumption that gAN depends on mA as for KSVZ axion model. These limits are stronger than obtained in previous laboratory-based experiments using nuclear reactor and artificial radioactive sources. (orig.)

  12. Nuclear magnetic resonance common laboratory, quadrennial report

    This quadrennial report of the nuclear magnetic resonance common laboratory gives an overview of the main activities. Among the different described activities, only one is interesting for the INIS database: it concerns the Solid NMR of cements used for radioactive wastes storage. In this case, the NMR is used to characterize the structure of the material and the composition, structure and kinetics of formation of the alteration layer which is formed at the surface of concrete during water leaching conditions. The NMR methodology is given. (O.M.)

  13. Nuclear Magnetic Resonance in Liquids and Solids

    The paper outlines the basic principles of nuclear magnetic resonance, trying wherever possible to compare and contrast the method with that of slow neutron scattering as a technique for studying the properties of condensed phases and especially of molecular and atomic motions. It is emphasized that this is not a review of nmr for an expert audience but has a pedagogical aim. It is hoped to give persons with a main interest in neutron scattering some appreciation of the scope and limitations of the nmr method. This is illustrated by recent results on one substance which covers many but by no means all of the important points. (author)

  14. Connection of nuclear magnetic and infiltration parameters of porous rocks

    The infiltration parameters of porous rocks are determined among others by the specific pore surface. In the case of the sandostones the nuclear magnetic behaviour of the water influx is also influenced by the specific surface of the pores. On this basis the nuclear magnetic and the infiltration parameters of the rocks can be brought into connection with each other. The paper deals with the rock-physics of the nuclear magnetic logging. (author)

  15. Nuclear magnetic resonance in hexaferrite/maghemite composite nanoparticles

    Kříšťan, P.; Hondlík, O.; Štěpánková, H.; Chlan, V.; Kouřil, K.; Řezníček, R.; Pollert, Emil; Veverka, Pavel

    Warszawa: Polish Academy of Sciences, 2015, s. 514-516. ISSN 0587-4246. [The European Conference PHYSICS OF MAGNETISM 2014/PM'14/. Poznań (PL), 23.06.2014-27.06.2014] Institutional support: RVO:68378271 Keywords : nuclear magnetic resonance and relaxation * ferrimagnetics * fine-particle systems * nanocrystalline materials * magnetic oxides * inorganic compounds Subject RIV: BM - Solid Matter Physics ; Magnetism

  16. Production cross section of At radionuclides from $^{7}$Li+$^{\\textrm{nat}}$Pb and $^{9}$Be+$^{\\textrm{nat}}$Tl reactions

    Maiti, Moumita

    2011-01-01

    Earlier we reported theoretical studies on the probable production of astatine radionuclides from $^{6,7}$Li and $^{9}$Be-induced reactions on natural lead and thalliun targets, respectively. For the first time, in this report, production of astatine radionuclides has been investigated experimentally with two heavy ion induced reactions: $^{9}$Be+$^{\\textrm{nat}}$Tl and $^{7}$Li+$^{\\textrm{nat}}$Pb. Formation cross sections of the evaporation residues, $^{207,208,209,210}$At, produced in (HI, xn) channel, have been measured by the stacked-foil technique followed by the off-line $\\gamma$-spectrometry at the low incident energies ($<$50 MeV). Measured excitation functions have been explained in terms of compound nuclear reaction mechanism using Weisskopf-Ewing and Hauser-Feshbach model. Absolute cross section values are lower than the respective theoretical predictions.

  17. Neutron characterization study for D–T, p-{sup 7}Li neutron sources with new BCA based direct collision coupling method

    Wang, Guan-bo, E-mail: wgb04dep@hotmail.com [Insititute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); Yang, Xin [Insititute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Qian, Da-zhi; Li, Run-dong; Tang, Bin [Insititute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China)

    2014-09-01

    The T(D,n){sup 4}He and {sup 7}Li(p,n){sup 7}Be neutron sources have been used for decades in nuclear physics research, stellar nucleosynthesis research and neutron therapy research. In this work, the neutron characterization including neutron yield, spectra, and angular distribution for D–T and p-{sup 7}Li sources have been studied with our new binary collision approximation (BCA) based direct collision coupling method. Distinguished from the traditional path integration method for getting the neutron weight, the new model establishes a relationship between the scattering cross section and the impact parameter, which allows the secondary neutron generation carrying out jointly with ions BCA tracking. The experimental measurements of neutron characterizations have been employed for these two reactions, and the new algorithm is validated.

  18. Reactions (d,7Li) and (d,7Be) in 19F nuclei

    Differential cross sections have been measured for the reactions 19F(d,7Li)14N, 19F(d,7Li(/sub 0.478/)14N, 19F(d,7Be)14C, and 19F(d,7Be(/sub 0.429/)14C in a cyclotron beam of deuterons with energy 13.6 MeV. The experimental data were analyzed by the distorted-wave method with inclusion of the finite interaction range and recoil. It is shown that the reactiuns 19F(d,7Li)14N and 19F(d,7Li(/sub 0.478/)14N occur mainly by direct transfer of a 5He cluster from the 4P/sub 1/2/ state of the 19F nucleus to the 1D/sub 3/2/ state of the 7Li nucleus. The differential cross sections for the reactions 19F(d,7Be)14C and 19F(d,7Be(/sub 0.429/)14C could not be explained in terms of the theory of direct transfer of a 5Li cluster

  19. Space distributions and decay probability for excited state of 7Li*(7,45 MeV) in reaction 7Li(alpha, alpha6Li)n

    Differential cross-sections of excitation and decay of 7Li*(7,45 MeV) resonance into 6Li + n channel in three particle reaction 7Li(alpha, alpha6Li)n at alpha-particle energy of 27,2 MeV have been determined in kinematically complete and incomplete experiments. Usage of position sensitive detector made it possible to obtain the data on space distributions of decay events for full range of possible angles and to determine the total probability of this process, which value essentially differs from the data for binary reactions. This result is agreed with previously obtained [1] and confirms the theoretical calculations [2] of decay branching ratio for short lived near-threshold resonances in three particle reactions

  20. Global optical model potentials for symmetrical lithium systems: 6Li+6Li, 7Li+7Li at Elab = 5-40 MeV

    Angular distributions of 6Li+6Li elastic scattering were measured for Elab=5-40 MeV. An optical model analysis of these data together with older data of 7Li+7Li elastic scattering taken at Elab = 8-17 MeV was performed with the aim to search for a ''global'' OM potential which describes elastic scattering in both Li-Li systems in a broad energy range. Both surface and volume absorbing potentials can be found which fulfill this requirement if a linear energy dependence is assumed of the depths of the real as well as the imaginary potential. These depths, if fitted to individual angular distributions, are found to vary in a correlated manner with the beam energy. This is taken as indication of strong coupling between elastic, inelastic, and reaction channels. This is corroborated by the existence of resonances in reaction channels at these energies where the potential depths are most pronouncedly changing. (orig.)

  1. Nuclear magnetic resonance spectrometer and method

    A nuclear magnetic resonance techniis described that allows simultaneous temperature determination and spectral acquisition. The technique employs a modification of the lock circuit of a varian xl-100 spectrometer which permits accurate measurement of the difference in resonance frequency between a primary lock nucleus and another , secondary, nucleus. The field stabilization function of the main lock circuit is not compromised. A feedback signal having a frequency equal to the frequency difference is substituted for the normal power supply in the spectrometer's existing radio frequency transmitter to modulate that transmitter. Thus, the transmitter's radio frequency signal is enhanced in a frequency corresponding to the resonance peak of the secondary nucleus. Determination of the frequency difference allows the determination of temperature without interference with the observed spectrum. The feedback character of the circuit and the presence of noise make the circuit self-activating

  2. Two-dimensional nuclear magnetic resonance petrophysics.

    Sun, Boqin; Dunn, Keh-Jim

    2005-02-01

    Two-dimensional nuclear magnetic resonance (2D NMR) opens a wide area for exploration in petrophysics and has significant impact to petroleum logging technology. When there are multiple fluids with different diffusion coefficients saturated in a porous medium, this information can be extracted and clearly delineated from CPMG measurements of such a system either using regular pulsing sequences or modified two window sequences. The 2D NMR plot with independent variables of T2 relaxation time and diffusion coefficient allows clear separation of oil and water signals in the rocks. This 2D concept can be extended to general studies of fluid-saturated porous media involving other combinations of two or more independent variables, such as chemical shift and T1/T2 relaxation time (reflecting pore size), proton population and diffusion contrast, etc. PMID:15833623

  3. Study on the differential cross sections of the (d, 7Li)-reactions on 13C nuclei

    Differential cross sections of 13C(d, 7Li)8Be and 13C(d, sup(7)Li*sub(0.478))sup(8)Be on 13.6 MeV deuteron cyclotron beam using the ΔExE technique to identify reaction products, in which silicon ΔE detectors, of approximately 5 mk thickness were applied, have been measured. Experimental data have been analyzed according to the Hauser- Feshbach statistical theory and in the approximation of distorted waves with account for finitude of interaction and recoil radius. It is shown that angular distributions of 7Li and sup(7)Li*sub(0.478) ions are described most satisfactorily in the approximation of direct transfer of 5He quasicluster from 2Dsub(1/2) state of 13C nucleus into 2Ssub(3/2) state of 7Li, sup(7)Li*sub(0.478) nuclei

  4. Phosphorus 31 nuclear magnetic resonance examination of female reproductive tissues

    Nuclear magnetic resonance spectroscopy is a powerful method of investigating the relationship between metabolism and function in living tissues. We present evidence that the phosphorus 31 spectra of myometrium and placenta are functions of physiologic state and gestational age. Specific spectroscopic abnormalities are observed in association with disorders of pregnancy and gynecologic diseases. Our results suggest that noninvasive nuclear magnetic resonance spectroscopy examinations may sometimes be a useful addition to magnetic resonance imaging examinations, and that nuclear magnetic resonance spectroscopy of biopsy specimens could become a cost-effective method of evaluating certain biochemical abnormalities

  5. Global optical-model potentials for the elastic scattering of sup(6,7)Li projectiles

    Simultaneous fits have been made to 44 6Li data sets covering the mass range 24-208 and the energy range 13-156 MeV in order to determine an average ('global') optical-model potential for 6Li scattering. A similar study has been made for 25 7Li data sets over the same mass range and an energy range of 28-88 MeV to find an average 7Li potential. With Saxon-Woods factors, constant values may be used for all parameters except for the depth of the imaginary potential which decreases in magnitude with increasing mass. The necessity of energy dependence, Coulomb correction and (for 7Li) a symmetry term is investigated. The variation of the integral properties of the potentials is discussed, and also a comparison is made for the two projectiles. Application of the global potentials is made to inelastic scattering and single-nucleon transfer reactions. (orig.)

  6. 7Li(3He,p)9Be reaction and primordial nucleosynthesis

    The differential cross section for the 7Li(3He, p)9Be reaction has been measured in 50 keV intervals at 8 angles (15deg-160deg) in the energy range from Ec.m.=0.5 to 2.0 MeV, and total cross sections were determined from these data. Since this reaction has been noted as being of possible importance in primordial nucleosynthesis, its astrophysical S-factor was calculated from the data. In addition, the S-factor for the 7Li(3H, n)9Be reaction, also of importance in primordial nucleosynthesis, was estimated from the 7Li(3He, p)9Be data and its thermonuclear reaction rate was calculated. (orig.)

  7. Study of fusion in 6,7Li+197Au near barrier energies

    Excitation functions are measured for complete fusion and transfer reactions of 6Li and 7Li with 197Au at energies around the Coulomb barrier. Coupled channel calculations including the couplings to both target and projectile excited states have been performed and are found to explain the data at energies below the barrier. At above barrier energies the complete fusion cross sections are found to be suppressed compared to the coupled channel calculations for both the systems. A systematic comparison of fusion cross-section for halo nuclei 6,8He and weakly bound stable nuclei 6,7Li on 197Au target is also presented. Large neutron transfer cross-sections are observed for 6,7Li as compared to tightly bound projectiles 12C,16O. (authors)

  8. Breakup mechanisms for 7Li + 197Au, 204Pb systems at sub-barrier energies

    Luong D.H.

    2013-12-01

    Full Text Available Coincidence measurements of breakup fragments were carried out for the 7Li + 197Au and 204Pb systems at sub-barrier energies. The mechanisms triggering breakup, and time-scales of each process, were identified through the reaction Q-values and the relative energy of the breakup fragments. Binary breakup of 7Li were found to be predominantly triggered by nucleon transfer, with p-pickup leading to 8Be → α + α decay being the preferred breakup mode. From the time-scales of each process, the coincidence yields were separated into prompt and delayed components, allowing the identification of breakup process important in the suppression of complete fusion of 7Li at above-barrier energies.

  9. Transport properties derived from ion-atom collisions: 6Li-6Li+ and 6Li-7Li+ Cases

    Bouledroua, Moncef; Bouchelaghem, Fouzia; LPR Team

    2014-10-01

    This investigation treats quantum-mechanically the ion- atom collisions and computes the transport coefficients, such as the coefficients of mobility and diffusion. For the case of lithium, the calculations start by determining the gerade and ungerade potential curves through which ionic lithium approaches ground lithium. Then, by considering the isotopic effects and nuclear spins, the elastic and charge-transfer cross sections are calculated for the case of 6Li+and7Li+ colliding with 6Li. Finally, the temperature-dependent diffusion and mobility coefficients are analyzed, and the results are contrasted with those obtained from literature. The main results of this work have been recently published in. This work has been realized within the frames of the CNEPRU Project D01120110036 of the Algerian Ministry of Higher Education.

  10. Elastic and inelastic angular distributions of the 7Li+120Sn system for energies near the Coulomb barrier

    Zagatto, V. A. B.; Oliveira, J. R. B.; Gasques, L. R.; Alcántara-Núñez, J. A.; Duarte, J. G.; Aguiar, V. P.; Medina, N. H.; Seale, W. A.; Pires, K. C. C.; Freitas, A.; Lubian, J.; Shorto, J. M. B.; Genezini, F. A.; Rossi, E. S., Jr.

    2016-06-01

    The reaction of 7Li+120Sn has been measured at bombarding energies of 21, 24 and 27 MeV. The {2}+\\to {0}+ γ -ray transition in 120Sn was observed and the angular distribution for the 2+ excited state was obtained. Coupled channels and coupled-reaction channels calculations, including the dynamical polarization potential due to the projectile break-up, obtained from continuum discretized coupled channel calculations, were performed. The comparison between the existing experimental elastic angular distribution with the coupled-reaction channels calculations indicates that the 1n stripping transfer is the most intense channel to be coupled and the 2n stripping reaction occurs sequentially rather than directly, however, further data must be analyzed to confirm this indication. The experimental elastic and inelastic scattering data were well described by the calculations, but some discrepancies in these channels may indicate the need for corrections to the nuclear potential and/or the necessity to incorporate further channels.

  11. Gamow shell model description of radiative capture reactions $^6$Li$(p,\\gamma)$$^7$Be and $^6$Li$(n,\\gamma)$$^7$Li

    Dong, G X; Fossez, K; Płoszajczak, M; Jaganathen, Y; Betan, R M Id

    2016-01-01

    According to standard stellar evolution, lithium abundance is believed to be a useful indicator of the stellar age. However, many evolved stars like red giants show huge fluctuations around expected theoretical abundances that are not yet fully understood. The better knowledge of nuclear reactions that contribute to the creation and destruction of lithium can help to solve this puzzle. In this work we apply the Gamow shell model (GSM) formulated in the coupled-channel representation (GSM-CC) to investigate the mirror radiative capture reactions $^6$Li$(p,\\gamma)$$^7$Be and $^6$Li$(n,\\gamma)$$^7$Li. The cross-sections are calculated using a translationally invariant Hamiltonian with the finite-range interaction which is adjusted to reproduce spectra, binding energies and one-nucleon separation energies in $^{6-7}$Li, $^7$Be. All relevant $E1$, $M1$, and $E2$ transitions from the initial continuum states to the final bound states $J={3/2}_1^-$ and $J={1/2}^-$ of $^7$Li and $^7$Be are included. We demonstrate th...

  12. Report for in-situ 7Li NMR experiment in PNNL Phase -1

    Hu, Jian Zhi [Pacific Northwest National Laboratory

    2014-08-19

    To understand the detailed local structural evolution, an in-situ 7Li NMR study was performed. An operando identification of the lithium germanide phases under various cycling regimens permitted understanding of the kinetics of phase transition between different structural phases, including the amorphous phases, and how these correlated with capacity retention. Combining data from TEM and in-situ 7Li NMR, we discovered that the phase inter-conversion during cycling was mediated by co-existing amorphous and crystalline phases, and that the high capacity observed was correlated with an over-lithiated lithium germanide phase.

  13. Search for higher excited states of $^{8}$Be* to study the cosmological $^{7}$Li problem

    We would like to study the unresolved $^{7}$Li abundance anomaly by carrying out experiments that destroy the rare isotope $^{7}$Be, the main source of $^{7}$Li. Utilizing a 35 MeV $^{7}$Be beam from HIE-ISOLDE, we would like to measure the (d,p) and (d,d) reactions with T-REX. The higher beam energy, for the first time, would allow us to measure higher excitation energies in $^{8}$Be up to about 20 MeV. With a wider angular coverage, we can make improved average cross-section measurement without assuming isotropy done in earlier works.

  14. Search for a resonant enhancement of the 7Be + d reaction and primordial 7Li abundances

    Big Bang nucleosynthesis calculations, constrained by the Wilkinson Microwave Anisotropy Probe results, produce 7Li abundances almost a factor of four larger than those extrapolated from observations. Since primordial 7Li is believed to be mostly produced by the beta decay of 7Be, one proposed solution to this discrepancy is a resonant enhancement of the 7Be(d,p)2α reaction rate through the 5/2+ 16.7-MeV state in 9B. The 2H(7Be,d)7Be reaction was used to search for such a resonance; none was observed. An upper limit on the width of the proposed resonance was deduced.

  15. Determination of degradation constants of energetic 7*Li ion in liquid media using a thin boron film on silicon wafer

    A novel method to determine degradation constants has been developed for energetic 7*Li ions produced from the 10B (n, α) 7*Li reaction, moving in liquid media. The energetic 7*Li generated in a thin boron film on silicon wafer plunged into a liquid sample in which the wafer was immersed. The degradation constants were determined by analyzing the Doppler-broadened lineshapes of prompt γ-ray at 478 keV emitted from 7*Li. For comparison, degradation constants were also measured for solutions of boron compounds. Values obtained by the two methods gave fair agreement. (author)

  16. Enhanced nuclear magnetism: some novel features and prospective experiments

    It is shown that methods used for studying nuclear magnetism and nuclear magnetic ordering can be extended to 'enhanced nuclear magnetism'. These methods include the use of r.f. fields for adiabatic demagnetization in the rotating frame (a.d.r.f) and beams of neutrons whose spins interact with the nuclear spins. The 'enhancement' of the nuclear moment arises from the electronic magnetization M1 induced through the hyperfine interaction. It is shown that the spatial distribution of M1 is the same as that of The Van Vleck magnetization induced by an external field, provided that J is a good quantum number. The spatial distributions are not in general the same in Russell-Saunders coupling, eg. in the 3d group. The Bloch equations are extended to include anisotropic nuclear moments. The 'truncated' spin Hamiltonian is derived for spin-spin interaction between enhanced moments. A general cancellation theorem for second-order processes in spin-lattice relaxation is derived. The interactions of neutrons with the true nuclear moment, the Van Vleck moment, the 'pseudonuclear' moment and the 'pseudomagnetic' nuclear moment are discussed. Ordered states of enhanced nuclear moment systems are considered, together with the conditions under which they might be produced by a.d.r.f. following dynamic nuclear polarization. (U.K.)

  17. Nuclear magnetic resonance of randomly diluted magnetic materials

    The temperature dependence of the nuclear relaxation rates and line shapes of the FO resonance in the diluted antiferromagnet Fex Zn1-x F2 and Mnx Zn1-x F2 are studied over a large temperature range TN 1) of the FO nuclei, which are not transfer hyperfine coupled to the Fe (or Mn) spins, have been measured and calculated as a function of the concentration x. Good agreement with experiment is found for the theoretical results, which have been obtained in the range 0.1 ≤ x ≤ 0.8. The temperature dependence of 1/T1 for TN1 data near TN was used to study Random Field Effects on the critical behavior of Mn.65 Zn.35 F2, for fields applied parallel and perpendicular to the easy (C) axis. It was found that the transition temperature TN depressed substantially with field only for Ho || C. The experimental results are in general accord with the theory for Random Field Effects in disordered, anisotropic antiferromagnets. The critical divergence of the inhomogeneously broadened FO NMR was studied in Fe.6 Zn.4 F2 above TN. The experimental results agree with Heller's calculation of the NMR line broadening by Random Field Effects. With Ho || C the line shape changes from Gaussian towards Lozentzian for t -2 and below TN its line width increase qualitatively following the increase in the sublattice magnetization. (author)

  18. Search for magnetic monopoles with nuclear track detectors

    Giorgini, M

    2000-01-01

    This paper describes an experimental search for GUT magnetic monopoles in the MACRO experiment using the nuclear track subdetector CR39. After discussing the working principle, the charge resolution and the calibration of the detector, the experimental procedure for searching for magnetic monopoles is described. Since no candidates were found, the upper flux limits obtained by the MACRO CR39 used as a "stand alone detector" for magnetic monopoles of different magnetic charges are presented.

  19. Sensitive Magnetic Control of Ensemble Nuclear Spin Hyperpolarisation in Diamond

    Wang, Hai-Jing; Avalos, Claudia E; Seltzer, Scott J; Budker, Dmitry; Pines, Alexander; Bajaj, Vikram S

    2012-01-01

    Dynamic nuclear polarisation, which transfers the spin polarisation of electrons to nuclei, is routinely applied to enhance the sensitivity of nuclear magnetic resonance; it is also critical in spintronics, particularly when spin hyperpolarisation can be produced and controlled optically or electrically. Here we show the complete polarisation of nuclei located near the optically-polarised nitrogen-vacancy (NV) centre in diamond. When approaching the ground-state level anti-crossing condition of the NV electron spins, 13C nuclei in the first-shell are polarised in a pattern that depends sensitively and sharply upon the magnetic field. Based on the anisotropy of the hyperfine coupling and of the optical polarisation mechanism, we predict and observe a complete reversal of the nuclear spin polarisation with a few-mT change in the magnetic field. The demonstrated sensitive magnetic control of nuclear polarisation at room temperature will be useful for sensitivity-enhanced NMR, nuclear-based spintronics, and quant...

  20. Nuclear magnetic resonance investigation of dynamics in poly(ethylene oxide)-based lithium polyether-ester-sulfonate ionomers

    Nuclear magnetic resonance (NMR) spectroscopy has been utilized to investigate the dynamics of poly(ethylene oxide)-based lithium sulfonate ionomer samples that have low glass transition temperatures. 1H and 7Li spin-lattice relaxation times (T1) of the bulk polymer and lithium ions, respectively, were measured and analyzed in samples with a range of ion contents. The temperature dependence of T1 values along with the presence of minima in T1 as a function of temperature enabled correlation times and activation energies to be obtained for both the segmental motion of the polymer backbone and the hopping motion of lithium cations. Similar activation energies for motion of both the polymer and lithium ions in the samples with lower ion content indicate that the polymer segmental motion and lithium ion hopping motion are correlated in these samples, even though their respective correlation times differ significantly. A divergent trend is observed for correlation times and activation energies of the highest ion content sample with 100% lithium sulfonation due to the presence of ionic aggregation. Details of the polymer and cation dynamics on the nanosecond timescale are discussed and complement the findings of X-ray scattering and Quasi Elastic Neutron Scattering experiments

  1. Design of a 7Li rotating target for neutron production using a Van de Graaff accelerator

    We present a rotating target used for the production of monokinetic neutron fluxes. The neutrons are produced from the 7Li(p,n)7Be reaction for fast neutron elastic and inelastic scattering experiments. This target has been operated with a proton beam current of 8 to 10 μA during six consecutive weeks and has given entire satisfaction

  2. THE NEW DETECTIONS OF 7Li/6Li ISOTOPIC RATIO IN THE INTERSTELLAR MEDIA

    We have determined the isotopic abundance ratio of 7Li/6Li in the interstellar media (ISMs) along lines of sight to HD169454 and HD250290 using the High-Dispersion Spectrograph on the Subaru Telescope. We also observed ζ Oph for comparison with previous data. The observed abundance ratios were 7Li/6Li = 8.1+3.6-1.8 and 6.3+3.0-1.7 for HD169454 and HD250290, respectively. These values are in reasonable agreement with those observed previously in the solar neighborhood ISMs within ±2σ error bars and are also consistent with our measurement of 7Li/6Li = 7.1+2.9-1.6 for a cloud along the line of sight to ζ Oph. This is good evidence for homogeneous mixing and instantaneous recycling of the gas component in the Galactic disk. We also discuss several source compositions of 7Li, Galactic cosmic-ray interactions, stellar nucleosynthesis, and big bang nucleosynthesis.

  3. Least Squares Magnetic-Field Optimization for Portable Nuclear Magnetic Resonance Magnet Design

    Single-sided and mobile nuclear magnetic resonance (NMR) sensors have the advantages of portability, low cost, and low power consumption compared to conventional high-field NMR and magnetic resonance imaging (MRI) systems. We present fast, flexible, and easy-to-implement target field algorithms for mobile NMR and MRI magnet design. The optimization finds a global optimum in a cost function that minimizes the error in the target magnetic field in the sense of least squares. When the technique is tested on a ring array of permanent-magnet elements, the solution matches the classical dipole Halbach solution. For a single-sided handheld NMR sensor, the algorithm yields a 640 G field homogeneous to 16,100 ppm across a 1.9 cc volume located 1.5 cm above the top of the magnets and homogeneous to 32,200 ppm over a 7.6 cc volume. This regime is adequate for MRI applications. We demonstrate that the homogeneous region can be continuously moved away from the sensor by rotating magnet rod elements, opening the way for NMR sensors with adjustable 'sensitive volumes'

  4. Nuclear magnetic resonance studies of metabolic regulation

    Nuclear magnetic resonance (NMR) techniques for the detection of the metabolic transformations of biological compounds labeled with stable isotopes, particularly carbon-13 have been explored. We have studied adipose tissue in the intact rat, the exteriorized epididymal fat pad, and the isolated adipocyte. Triacylglycerol metabolism in adipose tissue is regulated by lipogenic factors (insulin, corticosterone, thyroxine, and growth hormone) and lipolytic factors (glucagon and catecholamines). The synthesis of triglyceride from 5.5 mM glucose was stimulated by about 4-fold by 10 nM insulin. Triglyceride synthesis from glucose in the presence of insulin occurred at a rate of 330 nmol/hr/106 cells. Since the NMR signals from free and esterified fatty acids and glycerol are distinct, we could directly measure the rate of hormone-stimulated lipolysis. Epinephrine (10 μM) gave a lipolytic rate of 0.30 μmol/hr/106 cells as monitored by free-glycerol appearance in the medium. 13C NMR provides a superior method for the measurement of triglyceride metabolism since it directly measures the changes in the substrates and products in situ

  5. Nuclear Composition of Magnetized GRB Jets

    Shibata, Sanshiro

    2015-01-01

    We investigate the fraction of metal nuclei in the relativistic jets of gamma-ray bursts associated with core-collapse supernovae. We simulate the fallback in jet-induced explosions with two-dimensional relativistic hydrodynamics calculations and the jet acceleration with steady, radial, relativistic magnetohydrodynamics calculations, and derive detail nuclear composition of the jet by postprocessing calculation. We found that if the temperature at the jet launch site is above $4.7\\times 10^9$K, quasi-statistical equilibrium (QSE) is established and heavy nuclei are dissociated to light particles such as $^4$He during the acceleration of the jets. The criterion for the survival of metal nuclei is written in terms of the isotropic jet luminosity as $L_{\\rm j}^{\\rm iso} \\lesssim 3.9\\times 10^{50}(R_{\\rm i}/10^7{\\rm cm})^2 (1+\\sigma_{\\rm i})~{\\rm erg~s^{-1}}$, where $R_{\\rm i}$ and $\\sigma_{\\rm i}$ are the initial radius of the jets and the initial magnetization parameter, respectively. If the jet is initially d...

  6. Selectivity in multiple quantum nuclear magnetic resonance

    The observation of multiple-quantum nuclear magnetic resonance transitions in isotropic or anisotropic liquids is shown to give readily interpretable information on molecular configurations, rates of motional processes, and intramolecular interactions. However, the observed intensity of high multiple-quantum transitions falls off dramatically as the number of coupled spins increases. The theory of multiple-quantum NMR is developed through the density matrix formalism, and exact intensities are derived for several cases (isotropic first-order systems and anisotropic systems with high symmetry) to shown that this intensity decrease is expected if standard multiple-quantum pulse sequences are used. New pulse sequences are developed which excite coherences and produce population inversions only between selected states, even though other transitions are simultaneously resonant. One type of selective excitation presented only allows molecules to absorb and emit photons in groups of n. Coherent averaging theory is extended to describe these selective sequences, and to design sequences which are selective to arbitrarily high order in the Magnus expansion. This theory and computer calculations both show that extremely good selectivity and large signal enhancements are possible

  7. Nuclear magnetic resonance (NMR)-based metabolomics.

    Keun, Hector C; Athersuch, Toby J

    2011-01-01

    Biofluids are by far the most commonly studied sample type in metabolic profiling studies, encompassing blood, urine, cerebrospinal fluid, cell culture media and many others. A number of these fluids can be obtained at a high sampling frequency with minimal invasion, permitting detailed characterisation of dynamic metabolic events. One of the attractive properties of solution-state metabolomics is the ability to generate profiles from these fluids following simple preparation, allowing the analyst to gain a naturalistic, largely unbiased view of their composition that is highly representative of the in vivo situation. Solution-state samples can also be generated from the extraction of tissue or cellular samples that can be tailored to target metabolites with particular properties. Nuclear magnetic resonance (NMR) provides an excellent technique for profiling these fluids and is especially adept at characterising complex solutions. Profiling biofluid samples by NMR requires appropriate preparation and experimental conditions to overcome the demands of varied sample matrices, including those with high protein, lipid or saline content, as well as the presence of water in aqueous samples. PMID:21207299

  8. R-matrix analysis of reactions in the 9B compound system applied to the 7Li problem in BBN

    Paris, M.; Hale, G.; Hayes-Sterbenz, A.; Jungman, G.

    2016-01-01

    Recent activity in solving the ‘lithium problem’ in big bang nucleosynthesis has focused on the role that putative resonances may play in resonance-enhanced destruction of 7Li. Particular attention has been paid to the reactions involving the 9B compound nuclear system, d+7Be → 9B. These reactions are analyzed via the multichannel, two-body unitary R-matrix method using the code EDA developed by Hale and collaborators. We employ much of the known elastic and reaction data, in a four-channel treatment. The data include elastic 3He +6Li differential cross sections from 0.7 to 2.0 MeV, integrated reaction cross sections for energies from 0.7 to 5.0 MeV for 6Li(3He,p)8Be* and from 0.4 to 5.0 MeV for the 6Li(3He,d)7Be reaction. Capture data have been added to an earlier analysis with integrated cross section measurements from 0.7 to 0.825 MeV for 6Li(3He,γ)9B. The resulting resonance parameters are compared with tabulated values, and previously unidentified resonances are noted. Our results show that there are no near d+7Be threshold resonances with widths that are 10’s of keV and reduce the likelihood that a resonance-enhanced mass-7 destruction mechanism, as suggested in recently published work, can explain the 7Li problem.

  9. Nuclear magnetic tomography in the differential diagnosis of liver disease

    Roedl, W.

    1985-05-01

    In evaluating nuclear magnetic tomography for the diagnosis of liver disease, one must differentiate between circumscribed and diffuse lesions. Nuclear magnetic tomography provides additional information for lesions which are echogenic on ultrasound and can differentiate between metastases, haemangiomas and hamartomas. In diffuse parenchymal disease measurement of relaxation time can differentiate between fatty liver, cirrhosis (alcoholic, primary biliary), haemochromatosis (cirrhotic transformation) and hepatoma. NMR spectroscopy is a method for the future.

  10. Implementation of Quantum Logic Gates by Nuclear Magnetic Resonance Spectroscopy

    DU Jiang-Feng; WU Ji-Hui; SHI Ming-Jun; HAN Liang; ZHOU Xian-Yi; YE Bang-Jiao; WENG Hui-Ming; HAN Rong-Dian

    2000-01-01

    Using nuclear magnetic resonance techniques with a solution of cytosine molecules, we show an implementation of certain quantum logic gates (including NOT gate, square-root of NOT gate and controlled-NOT gate), which have central importance in quantum computing. In addition, experimental results show that nuclear magnetic resonance spectroscopy can efficiently measure the result of quantum computing without attendant wave-function collapse.

  11. GEOCHEMICAL CONTROLS ON NUCLEAR MAGNETIC RESONANCE MEASUREMENTS

    Proton nuclear magnetic resonance (NMR) is used in the Earth Sciences as a means of obtaining information about the molecular-scale environment of fluids in porous geological materials. Laboratory experiments were conducted to advance our fundamental understanding of the link between the NMR response and the geochemical properties of geological materials. In the first part of this research project, we studied the impact of both the surface-area-to-volume ratio (S/V) of the pore space and the surface relaxivity on the NMR response of fluids in sand-clay mixtures. This study highlighted the way in which these two parameters control our ability to use NMR measurements to detect and quantify fluid saturation in multiphase saturated systems. The second part of the project was designed to explore the way in which the mineralogic form of iron, as opposed to simply the concentration of iron, affects the surface relaxation rate and, more generally, the NMR response of porous materials. We found that the magnitude of the surface relaxation rate was different for the various iron-oxide minerals because of changes in both the surface-area-to-volume ratio of the pore space, and the surface relaxivity. Of particular significance from this study was the finding of an anomalously large surface relaxivity of magnetite compared to that of the other iron minerals. Differences in the NMR response of iron minerals were seen in column experiments during the reaction of ferrihydrite-coated quartz sand with aqueous Fe(II) solutions to form goethite, lepidocrocite and magnetite; indicating the potential use of NMR as a means of monitoring geochemical reactions. The final part of the research project investigated the impact of heterogeneity, at the pore-scale, on the NMR response. This work highlighted the way in which the geochemistry, by controlling the surface relaxivity, has a significant impact on the link between NMR data and the microgeometry of the pore space.

  12. 170 Nanometer Nuclear Magnetic Resonance Imaging using Magnetic Resonance Force Microscopy

    Thurber, K R; Smith, D D; Thurber, Kent R.; Harrell, Lee E.; Smith, Doran D.

    2003-01-01

    We demonstrate one-dimensional nuclear magnetic resonance imaging of the semiconductor GaAs with 170 nanometer slice separation and resolve two regions of reduced nuclear spin polarization density separated by only 500 nanometers. This is achieved by force detection of the magnetic resonance, Magnetic Resonance Force Microscopy (MRFM), in combination with optical pumping to increase the nuclear spin polarization. Optical pumping of the GaAs creates spin polarization up to 12 times larger than the thermal nuclear spin polarization at 5 K and 4 T. The experiment is sensitive to sample volumes containing $\\sim 4 \\times 10^{11}$ $^{71}$Ga$/\\sqrt{Hz}$. These results demonstrate the ability of force-detected magnetic resonance to apply magnetic resonance imaging to semiconductor devices and other nanostructures.

  13. Susceptibility effects in nuclear magnetic resonance imaging

    The properties of dephasing and the resulting relaxation of the magnetization are the basic principle on which all magnetic resonance imaging methods are based. The signal obtained from the gyrating spins is essentially determined by the properties of the considered tissue. Especially the susceptibility differences caused by magnetized materials (for example, deoxygenated blood, BOLD-effect) or magnetic nanoparticles are becoming more important for biomedical imaging. In the present work, the influence of such field inhomogeneities on the NMR-signal is analyzed. (orig.)

  14. TL response of pairs of 6LiF:Mg,Cu,Si/7LiF:Mg,Cu,Si and TLD-600/TLD-700 to 0.1–12 MeV neutrons

    Neutron dosimetery continues to remain an important and a challenging aspect of radiation protection due to the higher biological effectiveness of neutrons than that of gamma rays and the intricacy in the responses of the detectors. The need for personal dosimetry in mixed fields of neutrons and gamma rays has considerably increased due to the rising number of nuclear facilities, nuclear power plants, medical therapy equipment, accelerators and so on. The most widely used technique for personal dosimetry has been the albedo technique employing pairs of neutron sensitive 6LiF:Mg,Ti (TLD-600) and neutron insensitive 7LiF:Mg,Ti (TLD-700) thermoluminescent dosimeters (TLDs). Off late, LiF:Mg,Cu,Si has emerged as one of the most promising TLD material, having the advantages of high sensitivity, near tissue equivalence to gamma rays, negligible fading on pre and post-irradiation storage, thermal stability for readout and negligible residual signal after the readout. In this study, neutron energy response of indigenously developed 6LiF:Mg,Cu,Si and 7LiF:Mg,Cu,Si TLD pairs was evaluated to neutrons of energy from thermal to 11.6 MeV and was compared with the response of TLD-600 and TLD-700 pairs. The net TL per unit neutron dose for the 6LiF:Mg,Cu,Si/7LiF:Mg,Cu,Si TLD pair was found to be about 10 times of that of the TLD-600/TLD-700 pair. Unlike, TLD-600 and TLD-700, the glow curve structure of 6LiF:Mg,Cu,Si and 7LiF:Mg,Cu,Si remained almost the same for all the irradiations. Thus, 6LiF:Mg,Cu,Si and 7LiF:Mg,Cu,Si TLDs provided a better alternate to TLD-600 and TLD-700 for the dosimetry of mixed fields of neutrons and gamma rays. -- Highlights: ► High sensitivity 6Li and 7Li enriched LiF:Mg,Cu,Si TLDs have been developed at KAERI, Korea. ► Main TL glow peak remains unchanged for 6Li and 7Li enrichment and radiation type. ► Net TL/mSv is about 10 times of that of TLD-600/TLD-700 pairs

  15. A 7Li and 27Al NMR study of interaction of lithium hydride with aluminium

    Lithium hydride interaction with metal aluminium is studied using 7Li and 27Al NMR method within 100-700 deg C temperature interval. It is detected, that at temperatures exceeding 420 deg C a number of α', α'', β, γ, δ and δ' phases based on intermetallic LiAl9, LiAl3, LiAl, Li3Al2 and Li9Al4 compounds (IC) are produced in LiH-Al system, their concentrations and rates of production being dependent on the molar ratio of initial components r =[LiH]:[Al]. Production of a stable αphase of [Al] and two methastable α' and α''-phases based on LiAl3 and LiAl9, which are decayed at 530 deg C, is detected under minor molar lithium content. Values of 7Li and 27Al NMR shifts in IC are determined. (author)

  16. Probing transfer to unbound states of the ejectile with weakly bound 7Li on 93Nb

    Pandit, S K; Mahata, K; Keeley, N; Parkar, V V; Rout, P C; Martel, I; Palshetkar, C S; Kumar, A; Ramachandran, K; Patale, P; Chatterjee, A; Kailas, S

    2016-01-01

    The two-step process of transfer followed by breakup is explored by measuring a rather complete set of exclusive data for reaction channels populating states in the ejectile continua of the $^7$Li+$^{93}$Nb system at energies close to the Coulomb barrier. The cross sections for $\\alpha+\\alpha$ events from one proton pickup were found to be smaller than those for $\\alpha+d$ events from one neutron stripping and $\\alpha+t$ events from direct breakup of $^7$Li. Coupled channels Born approximation and continuum discretized coupled channels calculations describe the data well and support the conclusion that the $\\alpha+d$ and $\\alpha+\\alpha$ events are produced by direct transfer to unbound states of the ejectile.

  17. Role of the cluster structure of 7Li in the dynamics of fragment capture

    Exclusive measurements of prompt γ-rays from the heavy-residues with various light charged particles in the 7Li + 198Pt system, at an energy near the Coulomb barrier (E/Vb∼1.6) are reported. Recent dynamic classical trajectory calculations, constrained by the measured fusion, α- and t-capture cross-sections have been used to explain the excitation energy dependence of the residue cross-sections. These calculations distinctly illustrate a two-step process, breakup followed by fusion, in case of the capture of t and α clusters; whereas for 6He+p and 5He+d configurations, massive transfer is inferred to be the dominant mechanism. The present work clearly demonstrates the role played by the cluster structures of 7Li in understanding the reaction dynamics at energies around the Coulomb barrier.

  18. Revisiting the 7Li(p,n)7Be reaction near threshold

    In this work we review all the available experimental neutron data for the 7Li(p,n) reaction near threshold which is necessary to obtain an accurate source model for Monte Carlo simulations in Boron Neutron Capture Therapy. Scattered published experimental results such as cross sections, differential neutron yields and total yields were collected and analyzed, exploring the sensitivity of the fitting parameters to the different possible variables and deriving a consistent working set of parameters to evaluate the neutron source near threshold. - Highlights: • We review neutron experimental data for the 7Li(p,n) reaction near threshold. • A new computational method was used to study all the available published data. • A consistent description of the neutron source was derived fitting the available data. • We found that the neutron yield at 0° studied by Kononov is the most sensitive curve. • A consistent set of parameters to parametrize the Breit–Wigner formula is presented

  19. Nuclear magnetic resonance spectroscopy in pancreatic disorders

    Ofer Kaplan

    1997-03-01

    Full Text Available Nuclear magnetic resonance spectroscopy (NMRS is a powerful technique that enables continuous monitoring of biochemical processes in tissues and organs in a non-invasive manner. A model of isolated perfused rat pancreas, suitable for NMRS studies, was developed. Acute pancreatitis was induced by injections of either 0.5 ml 5% sodium taurocholate (TC into the bile duets, or 1.0 ml 10% TC injections into the pancreatic parenchyma. Phosphorous (31P NMRS of experimental pancreatitis were characterized by a transient signal at -0.18±0.04 ppm which was assigned as solubilized lecithin, and can be used as an indicator of the early phases of the discase. Depletion of the high energy phosphorous compounds, phosphocreatine and ATP, were also found during acute pancreatitis, and paralleled the extension of the pathological damage. The role of NMRS in pancreatic cancer diagnosis and its treatment were assessed in three models of pancreatic neoplasms. Perfused MIA PaCa-2 human pancreatic cancer cells, subcutancously implanted pancreatic tumors in hamsters, and pancreatic tumors induced in-situ in rats by direct appiication of the carcinogen 7,12-dimethyl benzanthracene, were studied by phosphorous (31P, sodium (23Na and proton (¹H NMRS. 31P spectra of pancreatic cancer were qualitatively similar to those of intact organs. However, 31P NMRS was found to be useful for monitoring the effects of treatment. Total (infra- and extracellular sodium concentrations, measured in the solid tumors, were similar in both the normal pancreas and the pancreatic tumors (39-40 mmol/g wet weight. Proton spectra of perchloric acid extracts revealed several differences between tumors and control pancreases. The principal findings were elevated levels of the amino acid taurine, from I.17±O.39 mmol/g wet weight in healthy pancreases, to 2.79±0.71 mmol/g wet weight in pancreatic carcinoma in rats, and lactate levels which increased from 0.92±0.2 to 6.19±1.93 mmol/g wet weight

  20. Excitation of continuum states in sup 7 Li and their decay by quantum tunneling

    Utsunomiya, H; Yamagata, T; Ohta, M; Aoki, Y; Hirota, K; Ieki, K; Iwata, Y; Katori, K; Hamada, S; Lui, Y W; Schmitt, R P; Typel, S; Baur, G

    1999-01-01

    Strong forward-backward asymmetries were found in the recent alpha-t coincidence measurement of Coulomb breakup of 42 MeV- sup 7 Li via continuum states. The competition between E1 and E2 multipolarities and higher order effects in Coulomb excitation were investigated by solving the time-dependent Schroedinger equation. It is shown that higher order effects are an essential ingredient to the observed large asymmetries. The relevant reaction mechanism is discussed.

  1. Exploring Light Neutron Rich Nuclei via the (7Li,7Be) Reaction

    A systematic study of the nuclei that can be described as an integer number of α particles plus three neutrons via the (7Li,7Be) reaction at about 8 MeV/u has shown the presence of Bound States Embedded in the Continuum in the energy spectra. These are experimental signatures of the dynamical correlations of an easily polarizable core with a single-particle state of the valence neutron.

  2. 7Li neutron-induced elastic scattering cross section measurement using a slowing-down spectrometer

    Heusch M.; Ghetta V.; Chabod S.; Brissot R.; Billebaud A.; Méplan O.; Kessedjian G.; Liatard E.

    2010-01-01

    A new integral measurement of the 7Li neutron induced elastic scattering cross section was determined in a wide neutron energy range. The measurement was performed on the LPSC-PEREN experimental facility using a heterogeneous graphite-LiF slowing-down time spectrometer coupled with an intense pulsed neutron generator (GENEPI-2). This method allows the measurement of the integral elastic scattering cross section in a slowing-down neutron spectrum. A Bayesian approach coupled to Monte Carlo cal...

  3. New measurement of the 10B(n,α)7 Li through the Trojan Horse Method

    Spartá, Roberta

    2016-04-01

    B(n,α) Li reaction cross section has been measured using the Trojan Horse method, with the specific aim to separate the α1 contribution (coming from the first Li excited level) by the αo (related to the Li ground state), using a very thin target. Preliminary results are shown of the three-body B(d,α7 Li)H cross section.

  4. The 3H(α,γ)7Li reaction at low energies

    The 3H(α,γ) reaction, and its mirror 3He(α,γ) are responsible for 7Li production in the big bang. Discrepancies between experimental data sets, as well as differences between the experimental and theoretical energy dependences, cause the 3H(α,γ)7Li cross section to be uncertain by as much as a factor of two at the relevant astrophysical energies (Ec.m. ∼ 100 keV). The authors report new measurements for 50 c.m. 3H targets and an 85% high-purity germanium detector. Angular distributions were measured at nine energies between 115 and 1200 kev. The astrophysical S-factor is observed to increase moderately with decreasing energy to S(0) ∼ 0.10 keV-b. The branching ratio for captures to the first excited state and ground state of 7Li is found to be ∼0.44, independent of energy. The results are compared to previous experiments and theoretical calculations

  5. In-beam PET measurement of $^{7}Li^{3+}$ irradiation induced $\\beta^+}$-activity

    Priegnitz, M; Parodi, K; Sommerer, F; Fiedler, F; Enghardt, W

    2008-01-01

    At present positron emission tomography (PET) is the only feasible method of an in situ and non-invasive monitoring of patient irradiation with ions. At the experimental carbon ion treatment facility of the Gesellschaft für Schwerionenforschung (GSI) Darmstadt an in-beam PET scanner has been integrated into the treatment site and lead to a considerable quality improvement of the therapy. Since ions other than carbon are expected to come into operation in future patient treatment facilities, it is highly desirable to extend in-beam PET also to other therapeutic relevant ions, e.g. 7Li. Therefore, by means of the in-beam PET scanner at GSI the β+-activity induced by 7Li3+ ions has been investigated for the first time. Targets of PMMA, water, graphite and polyethylene were irradiated with monoenergetic, pencil-like beams of 7Li3+ with energies between 129.1 A MeV and 205.3 A MeV and intensities ranging from 3.0 × 107 to 1.9 × 108 ions s−1. This paper presents the measured β+-activity profiles as well as d...

  6. Systematic model-dependent behaviour of fusion involving weakly bound projectiles 6,7Li

    Many measurements on complete fusion (CF) cross section at above barrier energies involving weakly bound stable projectiles (e.g., 6Li, 7Li and 9Be) show suppression by various degrees compared to theoretical estimates as well as experimental CF cross sections of reactions involving strongly bound projectiles. However, there is no concrete picture at sub-barrier energies. The conclusions based on coupled-channels (CC) calculations using different codes (e.g., FRESCO or CCFULL) may differ as the theoretical models used to calculate fusion are not same. In a recent paper on complete fusion in 7Li+152Sm system, the fusion cross sections calculated by CCFULL and FRESCO have been shown to be different despite using same bare potential. It was observed that with the inclusion of only inelastic couplings, the results of FRESCO were much closer to the experimental data in the above barrier region, while the CCFULL results overpredict the data over the entire range. To explore the above observation in different systems involving 6,7Li as projectile, in the present work, a systematic and detailed study has been carried out by means of CC calculations using both FRESCO and CCFULL. The aim is to analyze the differences between the two models of calculations

  7. Evaluation of d + 6,7Li data for deuteron incident energies up to 50 MeV

    A new evaluation of the nuclear data for a particle transport calculations was performed for d + 6,7Li interactions in the energy region from 4 to 50 MeV incident energy. Use was made of the available new optical model potential for d + Li interactions. For the description of a neutron emission a new optical model potential for n + 9Be was elaborated for the neutron energies from 0.1 to 22 MeV. Global optical model potentials were used for the neutrons above 22 MeV and for protons, tritons, He-3 and alphas - in the whole energy range. The following nuclear processes were accounted for: particle evaporation and preequilibrium emission, stripping of the proton from the deuteron and direct interactions of deuterons with lithium nuclei. GNASH and ECIS96 codes were applied for the first two process descriptions, the Serber model was utilised for stripping processes and the DWUCK4 code was used for direct reaction processes modelling. Total neutron emission spectra were calculated as a sum of the spectra in all these processes. A complete transport file was finally prepared in ENDF-6 format covering the deuteron incident energies up to 50 MeV. The newly evaluated data are in good agreement with experimental data for neutron emission spectra. The evaluated data files were successfully tested with a modified version of the MCNP computer code

  8. Comparison of nuclear electric resonance and nuclear magnetic resonance in integer and fractional quantum Hall states

    Tomimatsu, Toru, E-mail: tomimatsu@ils.uec.ac.jp; Shirai, Shota; Hashimoto, Katsushi, E-mail: hashi@m.tohoku.ac.jp; Sato, Ken [Department of Physics, Tohoku University, Sendai 980-8578 (Japan); Hirayama, Yoshiro [Department of Physics, Tohoku University, Sendai 980-8578 (Japan); WPI-Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan)

    2015-08-15

    Electric-field-induced nuclear resonance (NER: nuclear electric resonance) involving quantum Hall states (QHSs) was studied at various filling factors by exploiting changes in nuclear spins polarized at quantum Hall breakdown. Distinct from the magnetic dipole interaction in nuclear magnetic resonance, the interaction of the electric-field gradient with the electric quadrupole moment plays the dominant role in the NER mechanism. The magnitude of the NER signal strongly depends on whether electronic states are localized or extended. This indicates that NER is sensitive to the screening capability of the electric field associated with QHSs.

  9. Comparison of nuclear electric resonance and nuclear magnetic resonance in integer and fractional quantum Hall states

    Electric-field-induced nuclear resonance (NER: nuclear electric resonance) involving quantum Hall states (QHSs) was studied at various filling factors by exploiting changes in nuclear spins polarized at quantum Hall breakdown. Distinct from the magnetic dipole interaction in nuclear magnetic resonance, the interaction of the electric-field gradient with the electric quadrupole moment plays the dominant role in the NER mechanism. The magnitude of the NER signal strongly depends on whether electronic states are localized or extended. This indicates that NER is sensitive to the screening capability of the electric field associated with QHSs

  10. Comparison of nuclear electric resonance and nuclear magnetic resonance in integer and fractional quantum Hall states

    Toru Tomimatsu

    2015-08-01

    Full Text Available Electric-field-induced nuclear resonance (NER: nuclear electric resonance involving quantum Hall states (QHSs was studied at various filling factors by exploiting changes in nuclear spins polarized at quantum Hall breakdown. Distinct from the magnetic dipole interaction in nuclear magnetic resonance, the interaction of the electric-field gradient with the electric quadrupole moment plays the dominant role in the NER mechanism. The magnitude of the NER signal strongly depends on whether electronic states are localized or extended. This indicates that NER is sensitive to the screening capability of the electric field associated with QHSs.

  11. Effective Giromagnetic Ratios in Artifical Nuclear Magnetization Pumping of the Noble Gases Mix

    Popov E.N.

    2015-01-01

    Full Text Available Dynamic of the nuclear magnetization of the two noble gases mix was studied in this research. Nuclear magnetization pumped along the induction of external magnetic field. Vector of nuclear magnetization is given a tilt by the week rotational magnetic field, which makes NMR for noble gases. Interaction between the nuclear magnetic moments of the different noble gases adducted to shifts at the frequency of nuclear moments precession in external magnetic field. Effective gyromagnetic ratios of the nuclear of noble gases is defined and it different from the tabulated value. There is theoretical calculation of effective gyromagnetic ratios in this research.

  12. Probing the fusion of 7Li with 64Ni at near-barrier energies

    Shaikh, Md. Moin; Roy, Subinit; Rajbanshi, S.; Mukherjee, A.; Pradhan, M. K.; Basu, P.; Nanal, V.; Pal, S.; Shrivastava, A.; Saha, S.; Pillay, R. G.

    2016-04-01

    Background: The stable isotopes of Li, 6Li6 and 7Li, have two-body cluster structures of α +d and α +t with α -separation energies or breakup thresholds at 1.47 and 2.47 MeV, respectively. The weak binding of these projectiles introduces several new reaction channels not usually observed in the case of strongly bound projectiles. The impact of these breakup or breakup-like reaction channels on fusion, the dominant reaction process at near-barrier energies, with different target masses is of current interest. Purpose: Our purpose is to explore the fusion, at above and below the Coulmb barrier, of 7Li with 64Ni target in order to understand the effect of breakup or breakup-like processes with medium-mass target in comparison with 6Li, which has a lower breakup threshold. Measurement: The total fusion (TF) excitation of the weakly bound projectile 7Li with the medium-mass target 64Ni has been measured at the near-barrier energies (0.8 to 2 VB). The measurement was performed using the online characteristic γ -ray detection method. The complete fusion (CF) excitation function for the system was obtained using the x n -evaporation channels with the help of statistical model predictions. Results: At the above barrier energies CF cross sections exhibit an average suppression of about 6.5% compared to the one-dimensional barrier penetration model (1DBPM) predictions, while the model describes the measured TF cross section well. But below the barrier, both TF and CF show enhancements compared to 1DBPM predictions. Unlike 6Li, enhancement of CF for 7Li could not be explained by inelastic coupling alone. Conclusion: Whereas the σTF cross sections are almost the same for both the systems in the above barrier region, the suppression of σCF at above the barrier is less for the 7Li+64Ni system than for the 6+64Ni system. Also direct cluster transfer has been identified as the probable source for producing large enhancement in TF cross sections.

  13. Magnet Design Considerations for Fusion Nuclear Science Facility

    Zhai, Y. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Kessel, C. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); El-Guebaly, L. [Univ. of Wisconsin, Madison, WI (United States) Fusion Technology Institute; Titus, P. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

    2016-06-01

    The Fusion Nuclear Science Facility (FNSF) is a nuclear confinement facility that provides a fusion environment with components of the reactor integrated together to bridge the technical gaps of burning plasma and nuclear science between the International Thermonuclear Experimental Reactor (ITER) and the demonstration power plant (DEMO). Compared with ITER, the FNSF is smaller in size but generates much higher magnetic field, i.e., 30 times higher neutron fluence with three orders of magnitude longer plasma operation at higher operating temperatures for structures surrounding the plasma. Input parameters to the magnet design from system code analysis include magnetic field of 7.5 T at the plasma center with a plasma major radius of 4.8 m and a minor radius of 1.2 m and a peak field of 15.5 T on the toroidal field (TF) coils for the FNSF. Both low-temperature superconductors (LTS) and high-temperature superconductors (HTS) are considered for the FNSF magnet design based on the state-of-the-art fusion magnet technology. The higher magnetic field can be achieved by using the high-performance ternary restacked-rod process Nb3Sn strands for TF magnets. The circular cable-in-conduit conductor (CICC) design similar to ITER magnets and a high-aspect-ratio rectangular CICC design are evaluated for FNSF magnets, but low-activation-jacket materials may need to be selected. The conductor design concept and TF coil winding pack composition and dimension based on the horizontal maintenance schemes are discussed. Neutron radiation limits for the LTS and HTS superconductors and electrical insulation materials are also reviewed based on the available materials previously tested. The material radiation limits for FNSF magnets are defined as part of the conceptual design studies for FNSF magnets.

  14. Magnet design considerations for Fusion Nuclear Science Facility

    The Fusion Nuclear Science Facility (FNSF) is a nuclear confinement facility to provide a fusion environment with components of the reactor integrated together to bridge the technical gaps of burning plasma and nuclear science between ITER and the demonstration power plant (DEMO). Compared to ITER, the FNSF is smaller in size but generates much higher magnetic field, 30 times higher neutron fluence with 3 orders of magnitude longer plasma operation at higher operating temperatures for structures surrounding the plasma. Input parameters to the magnet design from system code analysis include magnetic field of 7.5 T at the plasma center with plasma major radius of 4.8 m and minor radius of 1.2 m, and a peak field of 15.5 T on the TF coils for FNSF. Both low temperature superconductor (LTS) and high temperature superconductor (HTS) are considered for the FNSF magnet design based on the state-of-the-art fusion magnet technology. The higher magnetic field can be achieved by using the high performance ternary Restack Rod Process (RRP) Nb3Sn strands for toroidal field (TF) magnets. The circular cable-in-conduit conductor (CICC) design similar to ITER magnets and a high aspect ratio rectangular CICC design are evaluated for FNSF magnets but low activation jacket materials may need to be selected. The conductor design concept and TF coil winding pack composition and dimension based on the horizontal maintenance schemes are discussed. Neutron radiation limits for the LTS and HTS superconductors and electrical insulation materials are also reviewed based on the available materials previously tested. As a result, the material radiation limits for FNSF magnets are defined as part of the conceptual design studies for FNSF magnets

  15. Sequence variations of in vitro pUC18 plasmid DNA induced by high energy 7Li ion beams implantation

    High energy heavy ion beams is a new mutagen for crop mutation breeding, but limited data are available on the molecular level induced by this mutagen. The in vitro pUC18 plasmid DNA was implanted by 7Li ion beams by doses of 0, 20, 40, 60, 80 and 100Gy, respectively, with the energy of 42.3Mev. The results showed that the damage effects induced by 7Li ion beams implantation was different from low LET rays, even low doses of 7Li ion beam could induce high damage on hydrogen bonds. Percentage of damages on hydrogen bonds of in vitro DNA induced by 7Li ion beams implantation increased with dosage increase up to 40Gy, then reduced with dosage increase, and higher than those of gamma rays in the same dosage. The relationship of dosage and damage percentage was different from that of gamma rays which was positive-linear correlation. Mutation frequency of 7Li ion beam implantation was 1.6 to 4.3 times to that of spontaneous mutation. The relationship of mutation frequency and dosage was similar with that of damage effects on hydrogen bonds, and showed a peak at 40Gy. The above results were identical with biological effects of wheat implanted by 7Li ion beams. Ten mutants were used for sequence analysis, which indicated that the types of base changes included base transversion, transition and deletion. Among all base changes detected, the frequency of bases transition (60%) was higher than that of bases transversion (30%) and bases deletion (10%). It seemed that thymine was more sensitive to the implantation than any other bases and base changes were mainly T→C and C→T. Bases between T and C were seemed to be easily induced by 7Li ion beams. The high percentage of DNA sequence variations could explain primarily the biological effects caused by 7Li ion beams in the M1 generation of crops. (author)

  16. Use of {sup 7}Li(p,n) reaction as a neutron source in a PGNAA setup

    Naqvi, A.A. [Department of Physics, King Fahd University of Petroleum and Minerals, Box No. 1815, Dhahran 31261 (Saudi Arabia)]. E-mail: aanaqvi@kfupm.edu.sa; Nagadi, M.M. [Department of Physics, King Fahd University of Petroleum and Minerals, Box No. 1815, Dhahran 31261 (Saudi Arabia)

    2005-03-01

    The performance of a {sup 7}Li(p,n) reaction-based Prompt Gamma Ray Neutron Activation Analysis (PGNAA) setup has been determined for analysis of Portland cement samples using Monte Carlo study. The calculations were carried out for a {sup 7}Li(p,n) reaction-based PGNAA setup with an external moderator similar to the one used in a previous 2.8 MeV neutrons-based PGNAA setup. The optimum values of geometry parameters of the {sup 7}Li(p,n) reaction-based setup are different from those of the 2.8 MeV neutrons-based setup resulting in better performance of the {sup 7}Li(p,n) reaction-based setup. The prompt {gamma}-ray yield from the {sup 7}Li(p,n) reaction-based setup is 60-70% higher than that from the 2.8 MeV neutrons-based setup. Although the performances of the {sup 7}Li(p,n) reaction-based setup is comparable with that of a previously studied {sup 3}H(p,n) reaction-based setup, yet performance of the {sup 7}Li(p,n) reaction-based setup is superior to that of the {sup 3}H(p,n) reaction-based setup because it has less radiation hazard due to utilization of non-radioactive neutron producing target. This study has provided a theoretical base for experimental test of a {sup 7}Li(p,n) reaction-based PGNAA setup.

  17. Nuclear Magnetic Resonance imaging; Resonance magnetique nucleaire

    Thibierge, M.; Sevestre, L.; Slupecki, P. [Centre Hospitalier de Charleville-Mezieres, 08 (France)

    1998-06-01

    After many years of low profile business in the USA, MRI is back. Improvements are focused on high field magnets and on low field magnets. The former, are dedicated to high quality imaging. The new scanners are more and more efficient because of the spreading use of real time imaging. They can do now, procedures that just could not be imagined some years ago. Vascular imaging is done routinely. Abdominal imaging in apnea of EPI, perfusion and diffusion imaging, and, last not least, all the field of functional imaging are on the verge of coming out. The new magnets unveiled in 1997 are lighter, smaller, more, user friendly, less impressive for patients subject to claustrophobia. They also need less helium to operate and less space to be sited. The latter, are dedicated to interventional procedures. The new magnets are wide opened and a lot of companies show off. Though Picker unveiled a new light superconductive 0.5 Tesla magnet, it seems that this kind of machines are about to disappear. No significant progress was noticed in the field of dedicated MRI devices. Some features can be highlighted: the new Siemens short bore and its table integrates the Panoramic Array Coil Concept. It will allow simultaneous scanning with up to four coils; the excellent homogeneity of the new Picker magnet that will allow spectroscopy at 1 Tesla; the twin gradients of the Elscint Prisma that will open the field of microscopy MRI; the Philips `floppy gradients` that could speed up 4 or 6 times, the time needed for imaging; some new sequences sensitive to temperature are studied as WIP; a lot of work is achieved on 3 or 4 Tesla scanners etc. (author)

  18. Computer Assisted Instruction (Cain) For Nuclear Magnetic Resonance Spectroscopy

    A computer assisted instruction program for nuclear magnetic resonance spectroscopy was developed by using Author ware 5.0, Adobe Image Styler 1.0, Adobe Photo shop 7.0 and Flash MX. The contents included the basic theory of 1H and 13C nuclear magnetic resonance (NMR) spectroscopy, the instrumentation of NMR spectroscopy, the two dimensional (2D) NMR spectroscopy and the interpretation of NMR spectra. The program was also provided examples, and exercises, with emphasis on NMR spectra interpretation to determine the structure of unknown compounds and solutions for self study. The questionnaire from students showed that they were very satisfied with the software

  19. Contribution to studies of magnetic nuclear dipolar order

    The magnetic nuclear dipolar order concept is first introduced. Two original studies on the 19F spin system of CaF2 are then presented; the first deals with the behavior of a dipolar nuclear antiferromagnetic material in the presence of an effective nonnull field and leads to the determination of the ''field-entropy'' phase diagram of the system; the second study reveals the existence of rotating transverse structures

  20. Implanted $^{7}$Be Targets For The Study of Neutron Interactions With $^{7}$Be : (The "Primordial $^{7}$Li Problem")

    The disagreement of the predicted abundance of primordial $^{7}$Li with the observed abundance is a longstanding problem in Big Bang Nucleosynthesis (BBN) theory (“Primordial $^{7}$Li problem”). While BBN theory correctly predicts the relative abundances of $^{2}$H/$^{1}$H, $^{3}$He/$^{1}$H and $^{4}$He/$^{1}$H (that vary over four orders of magnitudes), but it over-predicts the relative abundance of primordial $^{7}$Li/$^{1}$H by a factor of approximately 3-4 larger than observed (approximately 4-5$\\sigma$ discrepancy). Primordial $^{7}$Li is destroyed during the first 15 minutes primarily via the $^{7}$Li(p,$\\alpha$) reaction. Hence most of the primordial $^7$Li is predicted as the result of the (later when atoms are formed) electron capture $\\beta$-decay of the primordial $^{7}$Be that is produced primarily in the $^{3}$He($\\alpha$,$\\gamma$) )$^{7}$Be reaction. We propose to investigate the direct destruction of $^{7}$Be during (the first 15 minutes of) BBN via the $^{7}$Be(n,$\\alpha$) reaction to ch...

  1. Evaluation of nuclear magnetic resonance spectroscopy variability

    Introduction: the intrinsically high sensitivity of Magnetic Resonance Spectroscopy (MRS) causes considerable variability in metabolite quantification. In this study, we evaluated the variability of MRS in two research centers using the same model of magnetic resonance image scanner. Methods: two metabolic phantoms were created to simulate magnetic resonance spectra from in vivo hippocampus. The phantoms were filled with the same basic solution containing the following metabolites: N-acetyl-aspartate, creatine, choline, glutamate, glutamine and inositol. Spectra were acquired over 15 months on 26 acquisition dates, resulting in a total of 130 spectra per center. Results: the phantoms did not undergo any physical changes during the 15-month period. Temporal analysis from both centers showed mean metabolic variations of 3.7% in acquisitions on the same day and of 8.7% over the 15-month period. Conclusion: The low deviations demonstrated here, combined with the high specificity of Magnetic Resonance Spectroscopy, confirm that it is feasible to use this technique in multicenter studies in neuroscience research. (author)

  2. Evaluation of nuclear magnetic resonance spectroscopy variability

    Barreto, Felipe Rodrigues; Salmon, Carlos Ernesto Garrido, E-mail: garrido@ffclrp.usp.br [Universidade de Sao Paulo (FFCLRP/USP), Ribeirao Preto, SP (Brazil). Fac. de Filisofia, Ciencias e Letras; Otaduy, Maria Concepcion Garcia [Universidade de Sao Paulo (FAMUS/USP), Sao Paulo, SP (Brazil). Fac. de Medicina. Departamento de Radiologia

    2014-11-01

    Introduction: the intrinsically high sensitivity of Magnetic Resonance Spectroscopy (MRS) causes considerable variability in metabolite quantification. In this study, we evaluated the variability of MRS in two research centers using the same model of magnetic resonance image scanner. Methods: two metabolic phantoms were created to simulate magnetic resonance spectra from in vivo hippocampus. The phantoms were filled with the same basic solution containing the following metabolites: N-acetyl-aspartate, creatine, choline, glutamate, glutamine and inositol. Spectra were acquired over 15 months on 26 acquisition dates, resulting in a total of 130 spectra per center. Results: the phantoms did not undergo any physical changes during the 15-month period. Temporal analysis from both centers showed mean metabolic variations of 3.7% in acquisitions on the same day and of 8.7% over the 15-month period. Conclusion: The low deviations demonstrated here, combined with the high specificity of Magnetic Resonance Spectroscopy, confirm that it is feasible to use this technique in multicenter studies in neuroscience research. (author)

  3. Quantitative dosing by nuclear magnetic resonance

    The measurement of the absolute concentration of a heavy water reference containing approximately 99.8 per cent of D2O has been performed, by an original magnetic resonance method ('Adiabatic fast passage method') with a precision of 5.10-5 on the D2O concentration. (author)

  4. Exploring the N{alpha}+3n light nuclei via the ({sup 7}Li,{sup 7}Be) reaction

    Nociforo, C.; Cappuzzello, F.; Orrigo, S.E.A.; Winfield, J.S. [INFN-Laboratori Nazionali del Sud, Catania (Italy); Cunsolo, A.; Cavallaro, M. [INFN-Laboratori Nazionali del Sud, Catania (Italy); Universita di Catania, Dipartimento di Fisica e Astronomia, Catania (Italy); Foti, A. [Universita di Catania, Dipartimento di Fisica e Astronomia, Catania (Italy); INFN-Sezione di Catania, Catania (Italy); Fortier, S.; Beaumel, D. [Institut de Physique Nucleaire, Orsay Cedex (France); Lenske, H. [Universitaet Giessen, Institut fuer Theoretische Physik, Giessen (Germany)

    2006-03-15

    Experimental signatures of the dynamical correlations of a core with a single-particle neutron have been found in light neutron-rich nuclei investigated via the ({sup 7}Li,{sup 7}Be) charge-exchange reactions at around 8 MeV/u. Of particular astrophysical relevance are low-lying narrow resonances ({gamma}{proportional_to}200 keV FWHM) BSEC (Bound States Embedded in the Continuum). Because of their long lifetime BSEC states are likely to effect the capture rates in any scenario for nucleosynthesis in neutron-rich environment. They have been observed in the continuum of {sup 11}Be and {sup 15}C nuclei. A microscopic nuclear structure model based on QRPA theory, which takes into account Dynamical Core Polarisation (DCP) correlations, gives a suitable description of these resonances as well as single-particle states of the studied systems. In this context, high-energy narrow structures populated in nuclei having an integer number of {alpha}-particles plus three neutrons are good BSEC candidates and can be systematically investigated. (orig.)

  5. Solid state nuclear magnetic resonance: investigating the spins of nuclear related materials

    The author reviews his successive research works: his research thesis work on the Multiple Quantum Magic Angle Spinning (MQMAS) which is a quadric-polar nucleus multi-quanta correlation spectroscopy method, the modelling of NMR spectra of disordered materials, the application to materials of interest for the nuclear industry (notably the glasses used for nuclear waste containment). He presents the various research projects in which he is involved: storing glasses, nuclear magnetic resonance in paramagnetism, solid hydrogen storing matrices, methodological and instrument developments in high magnetic field and high resolution solid NMR, long range distance measurement by solid state Tritium NMR (observing the structure and dynamics of biological complex systems at work)

  6. Electron-nuclear magnetism of praseodymium and its compounds

    A consistent theory of electron-nuclear spin ordering in singlet magnetics is developed. The results of some recent experiments with PrNi5 are exlained. The effect of a magnetic field perpendicular to the basal plane on the phase transition is investigated. Depending on the magnitude of the exchange interaction, the magnetic field may either increase or decrease the transition temperature. An increase of the transition temperature on application of the field should occur, for example, in the hexagonal modification of praseodymium

  7. High Radiation Environment Nuclear Fragment Separator Magnet

    Kahn, Stephen [Muons, Inc., Batavia, IL (United States); Gupta, Ramesh [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-01-31

    Superconducting coils wound with HTS conductor can be used in magnets located in a high radiation environment. NbTi and Nb3Sn superconductors must operate at 4.5 K or below where removal of heat is less efficient. The HTS conductor can carry significant current at higher temperatures where the Carnot efficiency is significantly more favorable and where the coolant heat capacity is much larger. Using the HTS conductor the magnet can be operated at 40 K. This project examines the use of HTS conductor for the Michigan State University Facility For Rare Isotope Beams (FRIB) fragment separator dipole magnet which bends the beam by 30° and is located in a high radiation region that will not be easily accessible. Two of these magnets are needed to select the chosen isotope. There are a number of technical challenges to be addressed in the design of this magnet. The separator dipole is 2 m long and subtends a large angle. The magnet should keep a constant transverse field profile along its beam reference path. Winding coils with a curved inner segment is difficult as the conductor will tend to unwind during the process. In the Phase I project two approaches to winding the conductor were examined. The first was to wind the coils with curved sections on the inner and outer segments with the inner segment wound with negative curvature. The alternate approach was to use a straight segment on the inner segment to avoid negative curvature. In Phase I coils with a limited number of turns were successfully wound and tested at 77 K for both coil configurations. The Phase II program concentrated on the design, coil winding procedures, structural analysis, prototyping and testing of an HTS curved dipole coil at 40 K with a heat load representative of the radiation environment. One of the key criteria of the design of this magnet is to avoid the use of organic materials that would degrade rapidly in radiation. The Lorentz forces expected from the coils interacting with the

  8. Optimization and Construction of Single-side Nuclear Magnetic Resonance Magnet

    Ji Yongliang

    2013-10-01

    Full Text Available Single-sided NMR devices can operate under conditions inaccessible to conventional NMR while featuring portability and the ability to analyze arbitrary-sized objects. In this paper, a semi-elliptic Halbach magnet array was designed and built for single-side Nuclear Magnetic Resonance (NMR. We present an easy-to-implement target field algorithm for single-side NMR magnet design based on Gram-Schmidt Orthogonal method. The creating magnetic field of designed magnet structure could achieve best flatness in the region of interesting for NMR applications. The optimizing result shows that the best magnet structure can generate magnetic fields which flatly distributed in the horizontal direction and the gradient was distributed in the vertical direction with gradient of 2mT/mm. The field strength and gradient were measured by a three dimensions Hall probe and agreed well with the simulations.  

  9. Acoustic nuclear magnetic resonance in easy-axis antiferromagnets

    Obtained and investigated is the dispersion equation which shows that in the rouge of the tipping field at low temperatures the study of effects conditioned by the bond between the oscillations of electron and nuclear spins depends upon the fact, whethe the interaction of the sound with a nuclear spin subsystem is taken into account. The same concerns the effects conditioned by a strong bond between the oscillations of the lattice and electron spins. Shown is the effect of anisotropy of magnitostriction relative part on the nature of orientation phase transitions and the value of the coefficient of strengthening nuclear magnetic resonance

  10. Angular Distribution of the 12C(6He, 7Li)11B Reaction

    LI Er-Tao; LI Zhi-Hong; LI Yun-Ju; YAN Sheng-Quan; BAI Xi-Xiang; GUO Bing; SU Jun; WANG You-Bao; WANG Bao-Xiang; LIAN Gang; ZENG Sheng; FANG Xiao; ZHAO Wei-Juan; LIU Wei-Ping

    2009-01-01

    Angular distribution of the 12C(6He, 7Li)11B transfer reaction is measured with a secondary 6He beam of 36.4 Me V for the first time. The experimental angular distribution is well reproduced by the distorted-wave Born approxima-tion (DWBA) calculation. The success of the present experiment shows that it is feasible to measure one-nucleon transfer reaction on a light nucleus target with the secondary beam facility of the HI-13 tandem accelerator at China Institute of Atomic Energy (CIAE), Beifing.

  11. Phenomenological and microscopic optical potentials for 88 MeV 7Li scattering

    The elastic scattering cross sections for 88 MeV 7Li ions have been measured for targets of 2426Mg and 4048Ca. Analyses using both phenomenological and microscopic optical potentials provide information on the energy dependence of optical parameters, and the extent to which the potentials are determined for these light ions. The use of a double-folding microscopic model demonstrates the need for normalisation of the real potential by a factor of 0.5 in contrast to measurements at lower energies. The contribution of exchange effects, density dependence and break-up are discussed. (author)

  12. Nuclear magnetic resonance imaging in brain tumors

    Full text: Magnetic resonance imaging (MRI) is a non-invasive imaging method based on the detecting signal from hydrogen nuclei of water molecules and fat. Performances of MRI are continuously increasing, and its domains of investigation of the human body are growing in both morphological and functional study. MRI also allows It also performing advanced management of tumours especially in the brain, by combining anatomical information (morphological MRI), functional (diffusion, perfusion and BOLD contrast) and metabolic (tissue composition in magnetic resonance spectroscopy (MRS)). The MRI techniques have an important role in cancerology. These techniques allow essential information for the diagnosis and answering therapist's questions before, during or after the treatment. The MR allows clarifying the localization of expanding processes, the differential diagnosis between brain tumour and a lesion confined by another structural aspect, the diagnosis of the tumoral aspect of a lesion, the histological ranking in case of glial tumour and the extension of its localization as well as the therapeutic follow-up (pre-therapeutic and post-therapeutics assessments). A better combination between the morphological, functional and metabolic studies, as well as integrating new technical developments, especially while using a multichannel bird cage coils the 3T magnet and suitable computing software, would allow significant improvements of the exploration strategies and management of brain tumors.

  13. Microdosimetry spectra and RBE of {sup 1}H, {sup 4}He, {sup 7}Li and {sup 12}C nuclei in water studied with Geant4

    Burigo, Lucas, E-mail: burigo@fias.uni-frankfurt.de [Frankfurt Institute for Advanced Studies, Johann Wolfgang Goethe University, 60438 Frankfurt am Main (Germany); Institut für Theoretische Physik, Johann Wolfgang Goethe University, 60438 Frankfurt am Main (Germany); Pshenichnov, Igor, E-mail: pshenich@fias.uni-frankfurt.de [Frankfurt Institute for Advanced Studies, Johann Wolfgang Goethe University, 60438 Frankfurt am Main (Germany); Institute for Nuclear Research, Russian Academy of Sciences, 117312 Moscow (Russian Federation); Mishustin, Igor [Frankfurt Institute for Advanced Studies, Johann Wolfgang Goethe University, 60438 Frankfurt am Main (Germany); Kurchatov Institute, Russian Research Center, 123182 Moscow (Russian Federation); Bleicher, Marcus [Frankfurt Institute for Advanced Studies, Johann Wolfgang Goethe University, 60438 Frankfurt am Main (Germany); Institut für Theoretische Physik, Johann Wolfgang Goethe University, 60438 Frankfurt am Main (Germany)

    2014-02-01

    A Geant4-based Monte Carlo model for Heavy-Ion Therapy (MCHIT) is used to study radiation fields of {sup 1}H, {sup 4}He, {sup 7}Li and {sup 12}C beams with similar ranges (∼160–180 mm) in water. Microdosimetry spectra are simulated for wall-less and walled Tissue Equivalent Proportional Counters (TEPCs) placed outside or inside a phantom, as in experiments performed, respectively, at NIRS, Japan and GSI, Germany. The impact of fragmentation reactions on microdosimetry spectra is investigated for {sup 4}He, {sup 7}Li and {sup 12}C, and contributions from nuclear fragments of different charge are evaluated for various TEPC positions in the phantom. The microdosimetry spectra measured on the beam axis are well described by MCHIT, in particular, in the vicinity of the Bragg peak. However, the simulated spectra for the walled TEPC far from the beam axis are underestimated. Relative Biological Effectiveness (RBE) of the considered beams is estimated using a modified microdosimetric-kinetic model. Calculations show a similar rise of the RBE up to 2.2–2.9 close to the Bragg peak for helium, lithium and carbon beams compared to the modest values of 1–1.2 at the plateau region. Our results suggest that helium and lithium beams are also promising options for cancer therapy.

  14. A novel laser-collider used to produce monoenergetic 13.3 MeV 7Li (d, n) neutrons

    Zhao, J. R.; Zhang, X. P.; Yuan, D. W.; Li, Y. T.; Li, D. Z.; Rhee, Y. J.; Zhang, Z.; Li, F.; Zhu, B. J.; Li, Yan F.; Han, B.; Liu, C.; Ma, Y.; Li, Yi F.; Tao, M. Z.; Li, M. H.; Guo, X.; Huang, X. G.; Fu, S. Z.; Zhu, J. Q.; Zhao, G.; Chen, L. M.; Fu, C. B.; Zhang, J.

    2016-06-01

    Neutron energy is directly correlated with the energy of the incident ions in experiments involving laser-driven nuclear reactions. Using high-energy incident ions reduces the energy concentration of the generated neutrons. A novel “laser-collider” method was used at the Shenguang II laser facility to produce monoenergetic neutrons via 7Li (d, n) nuclear reactions. The specially designed K-shaped target significantly increased the numbers of incident d and Li ions at the keV level. Ultimately, 13.3 MeV neutrons were obtained. Considering the time resolution of the neutron detector, we demonstrated that the produced neutrons were monoenergetic. Interferometry and a Multi hydro-dynamics simulation confirmed the monoenergetic nature of these neutrons.

  15. A novel laser-collider used to produce monoenergetic 13.3 MeV (7)Li (d, n) neutrons.

    Zhao, J R; Zhang, X P; Yuan, D W; Li, Y T; Li, D Z; Rhee, Y J; Zhang, Z; Li, F; Zhu, B J; Li, Yan F; Han, B; Liu, C; Ma, Y; Li, Yi F; Tao, M Z; Li, M H; Guo, X; Huang, X G; Fu, S Z; Zhu, J Q; Zhao, G; Chen, L M; Fu, C B; Zhang, J

    2016-01-01

    Neutron energy is directly correlated with the energy of the incident ions in experiments involving laser-driven nuclear reactions. Using high-energy incident ions reduces the energy concentration of the generated neutrons. A novel "laser-collider" method was used at the Shenguang II laser facility to produce monoenergetic neutrons via (7)Li (d, n) nuclear reactions. The specially designed K-shaped target significantly increased the numbers of incident d and Li ions at the keV level. Ultimately, 13.3 MeV neutrons were obtained. Considering the time resolution of the neutron detector, we demonstrated that the produced neutrons were monoenergetic. Interferometry and a Multi hydro-dynamics simulation confirmed the monoenergetic nature of these neutrons. PMID:27250660

  16. A novel laser-collider used to produce monoenergetic 13.3 MeV 7Li (d, n) neutrons

    Zhao, J. R.; Zhang, X. P.; Yuan, D. W.; Li, Y. T.; Li, D. Z.; Rhee, Y. J.; Zhang, Z.; Li, F.; Zhu, B. J.; Li, Yan F.; Han, B.; Liu, C.; Ma, Y.; Li, Yi F.; Tao, M. Z.; Li, M. H.; Guo, X.; Huang, X. G.; Fu, S. Z.; Zhu, J. Q.; Zhao, G.; Chen, L. M.; Fu, C. B.; Zhang, J.

    2016-01-01

    Neutron energy is directly correlated with the energy of the incident ions in experiments involving laser-driven nuclear reactions. Using high-energy incident ions reduces the energy concentration of the generated neutrons. A novel “laser-collider” method was used at the Shenguang II laser facility to produce monoenergetic neutrons via 7Li (d, n) nuclear reactions. The specially designed K-shaped target significantly increased the numbers of incident d and Li ions at the keV level. Ultimately, 13.3 MeV neutrons were obtained. Considering the time resolution of the neutron detector, we demonstrated that the produced neutrons were monoenergetic. Interferometry and a Multi hydro-dynamics simulation confirmed the monoenergetic nature of these neutrons. PMID:27250660

  17. Nuclear magnetic response imaging of sap flow in plants

    Windt, C.W.

    2007-01-01

    This thesis deals with Nuclear Magnetic Resonance (NMR) imaging of long distance transport in plants. Long distance transport in plants is an enigmatic process. The theoretical framework that describes its basic properties has been in place for almost a century, yet at the same time only little is k

  18. Yeast Lipid Estimation by Enzymatic and Nuclear Magnetic Resonance Methods

    Moreton, R. S.

    1989-01-01

    Low-resolution nuclear magnetic resonance and enzymatic glycerol estimation were compared with a solvent extraction method for estimating the intracellular lipid content of lipid-accumulating yeasts. Both methods correlated well with the solvent extraction procedure and were more convenient with large numbers of samples.

  19. Selection of planes in nuclear magnetic resonance tomography

    A prototype aiming to obtain images in nuclear magnetic resonance tomography was developed, by adjusting NMR spectrometer in the IFQSC Laboratory. The techniques for selecting planes were analysed by a set of computer codes, which were elaborated from Bloch equation solutions to simulate the spin system behaviour. Images were obtained using planes with thickness inferior to 1 cm. (M.C.K.)

  20. Observation of the uranium 235 nuclear magnetic resonance signal

    Le Bail, H.; Chachaty, C.; Rigny, P.; Bougon, R.

    1983-01-01

    The first observation of the nuclear magnetic resonance of the uranium 235 is reported. It has been performed on pure liquid uranium hexafluoride at 380 K. The measured magnetogyric ratio is | γ(235U) | = 492.6 ± 0.2 rad.s-1 G-1.

  1. 13. Nuclear magnetic resonance users meeting. Extended abstracts book

    This annual meeting, held in Brazil from May 2 - 6, 2011 comprised seventeen lectures, given by invited speakers from Brazil and other countries, about the use of nuclear magnetic resonance for various analytical purposes; results from ninety five research works, most being carried out by scientific groups from various Brazilian R and D institutions, presented as congress panels/posters. A General Assembly meeting of AUREMN, the Brazilian Association of Nuclear Magnetic Resonance Users, also took place during the event. Main topics of the research works presented at this meeting were thus distributed: 54% in analytical chemistry (mainly organic chemistry, both experimental and theoretical works), 18% in applied life sciences (agricultural and food sciences, biological sciences and medicine), 15% in materials science (including nanostructures, petroleum and alternative fuels), 10% in mathematical methods and computing for the interpretation of NMR data, and the remaining 3% in improvements in instrumentation interfaces or magnetic field configurations.

  2. 13. Nuclear magnetic resonance users meeting. Extended abstracts book

    NONE

    2011-07-01

    This annual meeting, held in Brazil from May 2 - 6, 2011 comprised seventeen lectures, given by invited speakers from Brazil and other countries, about the use of nuclear magnetic resonance for various analytical purposes; results from ninety five research works, most being carried out by scientific groups from various Brazilian R and D institutions, presented as congress panels/posters. A General Assembly meeting of AUREMN, the Brazilian Association of Nuclear Magnetic Resonance Users, also took place during the event. Main topics of the research works presented at this meeting were thus distributed: 54% in analytical chemistry (mainly organic chemistry, both experimental and theoretical works), 18% in applied life sciences (agricultural and food sciences, biological sciences and medicine), 15% in materials science (including nanostructures, petroleum and alternative fuels), 10% in mathematical methods and computing for the interpretation of NMR data, and the remaining 3% in improvements in instrumentation interfaces or magnetic field configurations.

  3. Nuclear magnetic resonance imaging and prostatic cancer

    The diagnosis of prostatic cancer is histological. Apart from rectal examination, only imaging techniques allow evaluation of the extension of the cancer. Magnetic Resonance imaging (MRI) was performed with a Magniscan 5000 (Thomson C.G.R., France) apparatus. Three types of sequences were used: a short RT sequence (30/500, a multi-echo sequence with a long RT (40/2500) and echo gradient sequences (12 scans in less than 3 minutes). The MRI study of the pelvis is favoured by the abundance of fat which gives good contrast, spontaneous visualization of the vessels and the presence of the bladder with a high signal for urine in T2. This provides a very good anatomical study in three planes. In prostatic cancer, the study of the long sequence signal reveals heterogeneity of the prostatic signal on the second echo, but this is a non-specific variation. The staging of prostatic cancer is facilitated by scans in three planes. Different examples are presented in relation to various stages of the disease. Three clinical cases demonstrate that Magnetic Resonance may become an important element in the choice of treatment

  4. General anesthesia for nuclear magnetic resonance imaging

    The core of the MAGNETOM diagnostic device is a liquid helium-cooled cryogenic magnet, having the shape of a hollow cylinder about 2 m long, 50 to 60 cm i.d. Its inner space is designed to accommodate a bench with the patient, whose part examined, usually the head, is enclosed in a smaller coil and is located roughly in the center of the magnet. The examination takes 4 to 20 minutes, during which the patient must be fixed to prevent any motion. Inhalation anesthesia with spontaneous ventilation using the Jackson-Rees or Bain's system and a laryngeal mask is considered the safest way where no special equipment is employed. If artificial ventilation is necessary, balanced anesthesia with either manual ventilation using Bain's system or a fluidic type ventilator seems to be the best choice. The preparation of the patient prior to the examination, the premedication, and the monitoring equipment are described. (J.B.). 1 tab., 5 figs., 11 refs

  5. Monte Carlo modelling of a TLD device containing 7LiF:Mg,Cu,P detectors

    The Monte Carlo code MCNP-4C2 is used to design a new personal thermoluminescence dosemeter that assesses both Hp(10) and Hp(0.07) in mixed photon/electron fields. The new dosemeter utilizes two 7LiF:Mg,Cu,P elements contained within a Harshaw TLD-700H card, itself inside a polypropylene holder with walls 2 mm thick. Several potential designs of holder are considered; the best incorporates a polytetrafluoroethylene cylinder of diameter 18 mm and thickness 4.3 mm that acts as a filter to provide the correct electron cut-off and an acceptably flat Hp(10) relative response to photons, with an open hole in front of the Hp(0.07) element. Response characteristics for both detectors in this final design are presented for irradiation from a variety of angles of interest, with source energies between 16 and 6174 keV used. Comparison is made between modelled and measured data at normal incidence; the relative responses generally agree well. A new estimate for the relative light conversion efficiency relevant to the 7LiF:Mg,Cu,P is also derived and presented

  6. Corrosion barriers processed by Al electroplating and their resistance against flowing Pb–15.7Li

    In the HCLL blanket design, ferritic–martensitic steels are in direct contact with the flowing liquid breeder Pb–15.7Li and have to withstand severe corrosion attack. Beyond corrosion, T-permeation from the breeder into the RAFM-steels is also an important issue and has to be reduced significantly. Earlier work showed that Al-based coatings can act as barriers for both, however, applied processes e.g. HDA or VPS exhibited strong drawbacks in the past. Meanwhile new industrial relevant coating processes, using electroplating technology are under development and called ECA (electrochemical aluminization) and ECX (electrochemical deposition from ionic liquids) process. In this study electrochemically Al-coated and heat-treated Eurofer samples were tested in PICOLO loop for exposure times up to 12,000 h (ECA) and 2000 h (first results ECX) respectively to determine corrosion properties in flowing Pb–15.7Li (550 °C, 0.1 m/s). Cross section analysis afterward corrosion testing proved the ability of thin Al-based barriers made by electrochemical techniques to protect the bare Eurofer from corrosion attack even at exposure times of 12,000 h. Determined radial corrosion rates lay between 10 and 20 μm/a. First results for ECX coated samples (2000 h) revealed more homogeneous corrosion behavior of the barrier layer itself compared to ECA

  7. Corrosion barriers processed by Al electroplating and their resistance against flowing Pb–15.7Li

    Krauss, Wolfgang, E-mail: wolfgang.krauss@kit.edu; Konys, Jürgen; Wulf, Sven-Erik

    2014-12-15

    In the HCLL blanket design, ferritic–martensitic steels are in direct contact with the flowing liquid breeder Pb–15.7Li and have to withstand severe corrosion attack. Beyond corrosion, T-permeation from the breeder into the RAFM-steels is also an important issue and has to be reduced significantly. Earlier work showed that Al-based coatings can act as barriers for both, however, applied processes e.g. HDA or VPS exhibited strong drawbacks in the past. Meanwhile new industrial relevant coating processes, using electroplating technology are under development and called ECA (electrochemical aluminization) and ECX (electrochemical deposition from ionic liquids) process. In this study electrochemically Al-coated and heat-treated Eurofer samples were tested in PICOLO loop for exposure times up to 12,000 h (ECA) and 2000 h (first results ECX) respectively to determine corrosion properties in flowing Pb–15.7Li (550 °C, 0.1 m/s). Cross section analysis afterward corrosion testing proved the ability of thin Al-based barriers made by electrochemical techniques to protect the bare Eurofer from corrosion attack even at exposure times of 12,000 h. Determined radial corrosion rates lay between 10 and 20 μm/a. First results for ECX coated samples (2000 h) revealed more homogeneous corrosion behavior of the barrier layer itself compared to ECA.

  8. Total kinetic energy distribution of fission fragments in 6,7Li + 238U reactions

    The shape and width of fission-fragment (FF) mass and kinetic energy distribution provides a lot of information on the fission reaction mechanism and the structure of the compound nucleus (CN), the fragments as well as the interacting nuclei. The shape of the mass distribution of the fission fragments for the actinides induced by the proton or neutron is known to change with the incident energy. At low energies, it shows a double humped distribution which changes slowly to a single humped distribution as energy increases. However, for a reaction involving a weakly bound projectile (i.e., 6Li + 232Th), a sharp change in the shape of the mass distribution with energy was observed. The sharp increase in the peak to valley ratio (P:V) in the fission-fragment mass distribution in 6Li + 232Th reaction by Itkis et al. and in 6,7Li + 238U reactions by Santra et al. was concluded to be due to the reduced energy transfer to the composite system caused by incomplete fusion (ICF) of alpha or deuteron/triton followed by fissions. Total Kinetic Energy (TKE) distribution of fission fragments is another important observable on which the effect of projectile breakup is not explored yet. In this contribution, the study of breakup/transfer effect on average TKE distribution for 6,7Li + 238U reactions is presented

  9. Nuclear magnetic resonance studies of biological systems

    The difference between intracellular and extracellular proton relaxation rates provides the basis for the determination of the mean hemoglobin concentration (MHC) in red blood cells. The observed water T1 relaxation data from red blood cell samples under various conditions were fit to the complete equation for the time-dependent decay of magnetization for a two-compartment system including chemical exchange. The MHC for each sample was calculated from the hematocrit and the intracellular water fraction as determined by NMR. The binding of the phosphorylcholine (PC) analogue, 2-(trimethylphosphonio)-ethylphosphate (phosphoryl-phosphocholine, PPC) to the PC binding myeloma proteins TEPC-15, McPC 603, and MOPC 167 was studied by 31P NMR

  10. Nuclear magnetic resonance imaging at microscopic resolution

    Johnson, G. Allan; Thompson, Morrow B.; Gewalt, Sally L.; Hayes, Cecil E.

    Resolution limits in NMR imaging are imposed by bandwidth considerations, available magnetic gradients for spatial encoding, and signal to noise. This work reports modification of a clinical NMR imaging device with picture elements of 500 × 500 × 5000 μm to yield picture elements of 50 × 50 × 1000 μm. Resolution has been increased by using smaller gradient coils permitting gradient fields >0.4 mT/cm. Significant improvements in signal to noise are achieved with smaller rf coils, close attention to choice of bandwidth, and signal averaging. These improvements permit visualization of anatomical structures in the rat brain with an effective diameter of 1 cm with the same definition as is seen in human imaging. The techniques and instrumentation should open a number of basic sciences such as embryology, plant sciences, and teratology to the potentials of NMR imaging.

  11. Enhanced Nuclear Magnetism: Some Novel Features and Prospective Experiments

    Abragam, A.; Bleaney, B.

    1983-06-01

    This review of enhanced nuclear magnetism discusses a number of features not previously considered, with special reference to new experiments that use dynamic methods to produce high nuclear polarization, followed by adiabatic demagnetization in the rotating frame (a.d.r.f.) to produce nuclear ordered states that may be investigated by the scattering of beams of neutrons. Section 2. The 'enhancement' of the nuclear moment arises from the electronic magnetization M_I induced through the hyperfine interaction. It is shown that the spatial distribution of M_I is the same as that of M_H, the Van Vleck magnetization induced by an external field, provided that J is a good quantum number. The spatial distributions are not in general the same in Russell-Saunders coupling, e.g. in the 3d group. Section 3. The Bloch equations are extended to include anisotropic nuclear moments. Section 4. The 'truncated' spin Hamiltonian is derived for spin-spin interaction between enhanced moments. Section 5. A general cancellation theorem for second-order processes in spin-lattice relaxation is derived, showing that the intrinsic direct process must be of third order. The relaxation rate obeys an equation similar to that for Kramers electronic ions, but reduced as the fifth power of the resonance frequencies. The relaxation rates observed experimentally (except in very high fields) are ascribed to paramagnetic impurities, so that these can be used to produce dynamic nuclear polarization (d.n.p.). Section 6. The interactions of neutrons with the true nuclear moment μ_I, the Van Vleck moment M_H, the 'pseudonuclear' moment M_I and the 'pseudomagnetic' nuclear moment μ *_I are discussed. It is shown that the four contributions can be observed separately by measurement of the form factor for neutron scattering as a function of temperature and direction of the applied magnetic field. Precession of the neutron spin in the 'pseudomagnetic' field H* is discussed with reference to the case of Ho

  12. Nuclear magnetic resonance in pulse radiolysis. Chemically induced dynamic nuclear polarization

    Nuclear magnetic resonance and chemically induced dynamic nuclear polarization (CIDNP) were applied to the study of pulse radiolysis. Samples were irradiated with a 3-MeV electron beam from the Argonne Van de Graaff accelerator in an EPR magnet (approximately 4000 G) which had axial holes for beam access. A fast flow system transferred the irradiated solution to the rotating 5-mm NMR sample tube. The NMR spectra of mixtures of sodium acetate and methanol were presented to demonstrate the features of the CIDNP in pulse radiolysis

  13. Nuclear magnetic resonance method for observation of ferromagnetic pulmonary contaminants

    A method is proposed for measurement of tissue concentration of asbestos and other contaminants containing magnetite. The method uses nuclear magnetic resonance (NMR) of protons as a means of detection of the magnetic particles present in the dust. Results of the study of the effect of concentration of iron particles and particle size on the NMR signal are presented. The NMR signal had linear relationship to the concentration particles. Experiments with different particle size indicated that the signal was proportional to the mass of particles rather than to their number. Quantitative detection of 7RF02 chrysotile asbestos in gel and in rat lungs was demonstrated

  14. Algorithmic cooling in liquid-state nuclear magnetic resonance

    Atia, Yosi; Elias, Yuval; Mor, Tal; Weinstein, Yossi

    2016-01-01

    Algorithmic cooling is a method that employs thermalization to increase qubit purification level; namely, it reduces the qubit system's entropy. We utilized gradient ascent pulse engineering, an optimal control algorithm, to implement algorithmic cooling in liquid-state nuclear magnetic resonance. Various cooling algorithms were applied onto the three qubits of C132-trichloroethylene, cooling the system beyond Shannon's entropy bound in several different ways. In particular, in one experiment a carbon qubit was cooled by a factor of 4.61. This work is a step towards potentially integrating tools of NMR quantum computing into in vivo magnetic-resonance spectroscopy.

  15. Nuclear magnetic resonance in environmental engineering: principles and applications.

    Lens, P N; Hemminga, M A

    1998-01-01

    This paper gives an introduction to nuclear magnetic resonance spectroscopy (NMR) and magnetic resonance imaging (MRI) in relation to applications in the field of environmental science and engineering. The underlying principles of high resolution solution and solid state NMR, relaxation time measurements and imaging are presented. Then, the use of NMR is illustrated and reviewed in studies of biodegradation and biotransformation of soluble and solid organic matter, removal of nutrients and xenobiotics, fate of heavy metal ions, and transport processes in bioreactor systems. PMID:10335581

  16. Study of the reactions 9Be (d, a0) 7Li, 9Be (d, a1) 7Li*, 9Be (dt)8Be and 9Be (dp0) 10Be from 300 to 1000 keV

    We present the excitation curves, the angular distributions and the total cross-sections for the reactions: 9Be (d α0)7Li, 9Be (d α1)7Li, 9Be (d, t)8Be, 9Be (dp0)10Be, in the energy range from 300 keV to 1 MeV. Our results are in good agreement with the few studies already carried out. In order that the results be presented in absolute values, we have normalized them with those of BIGGERSTAFF. (author)

  17. 1H and 7Li NMR in li2-xhxmo3 (m = Ti, Zr)

    Baklanova, Ya

    2008-01-01

    Nuclear magnetic resonance (NMR), Raman spectroscopy and thermogravimetric methods were used to study the peculiarities of lithium ion replacement by protons in lithium metallates Li2MO3 (M=Ti, Zr). In this article we show that almost all protons in the final substitution products H2MO3 enter into the crystal structure. All protons in zirconium hydroxide belong to hydrogen-bonded OH-groups. Contrary, titanium hydroxide contains both hydrogen-bonded and isolated OH-groups. Protons in H2ZrO3 fo...

  18. Nuclear chiral and magnetic rotation in covariant density functional theory

    Meng, Jie

    2016-01-01

    Excitations of chiral rotation observed in triaxial nuclei and magnetic and/or antimagnetic rotations seen in near-spherical nuclei have attracted a lot of attention. Unlike conventional rotation in well-deformed or superdeformed nuclei, here the rotational axis is not necessary coinciding with any principal axis of the nuclear density distribution. Thus, tilted axis cranking is mandatory to describe these excitations self-consistently in the framework of covariant density functional theory (CDFT). We will briefly introduce the formalism of tilted axis cranking CDFT and its application for magnetic and antimagnetic rotation phenomena. Configuration-fixed CDFT and its predictions for nuclear chiral configurations and for favorable triaxial deformation parameters are also presented, and the discoveries of the multiple chiral doublets (M\\c{hi}D) in 133Ce and 103Rh are discussed.

  19. Nuclear chiral and magnetic rotation in covariant density functional theory

    Meng, Jie; Zhao, Pengwei

    2016-05-01

    Excitations of chiral rotation observed in triaxial nuclei and magnetic and/or antimagnetic rotations (AMR) seen in near-spherical nuclei have attracted a lot of attention. Unlike conventional rotation in well-deformed or superdeformed nuclei, here the rotational axis is not necessary coinciding with any principal axis of the nuclear density distribution. Thus, tilted axis cranking (TAC) is mandatory to describe these excitations self-consistently in the framework of covariant density functional theory (CDFT). We will briefly introduce the formalism of TAC–CDFT and its application for magnetic and AMR phenomena. Configuration-fixed CDFT and its predictions for nuclear chiral configurations and for favorable triaxial deformation parameters are also presented, and the discoveries of the multiple chiral doublets in 133Ce and 103Rh are discussed.

  20. Medium energy nuclear physics research

    The topics briefly discussed in this paper are: 117Sn magnetic scattering; 41Ca elastic magnetic scattering; 13C(e,e') high Q M1; deuteron threshold electrodisintegration; 10B(e,e') M3; 27Al elastic longitudinal and transverse scattering; transverse electron scattering from 14C; elastic magnetic scattering from 89Y; transverse and longitudinal electron scattering from 7Li; out-of-plane measurements of the d(e,e'p) coincidence cross out sections near threshold; 116Sn(e,e'n) coincidence study; results from background studies; 10B(e,e'p) coincidence study; 15N(e,e') longitudinal inelastic scattering; experimental work planned at CEBAF; electron scattering from the deuteron; nucleon form factors; measurement of R for hydrogen and deuterium; electroproduction of hadrons at LEP; weak interaction: parity violation in electron and proton scattering; large-basis shell model calculations; electromagnetic interactions; and relativistic nuclear physics

  1. Study of the {sup 7}Li (p,{alpha}){sup 4}He Reaction at Astrophysical Energies Through the Trojan Horse Method

    Pellegriti, M.G.; Aliotta, M.; Cherubini, S.; Lattuada, M.; Miljanic, D.; Pizzone, R.G.; Romano, S.; Soic, N.; Spitaleri, C.; Zadro, M.; Zappala, R.A.

    2000-12-31

    The Trojan Horse Method has been applied to obtain information about {sup 7}Li(p,{alpha}),{sup 4}He reaction at astrophysical energies. The {sup 7}Li(d,{alpha} n){sup 4}He reaction has been used and the two body reaction cross section for the {sup 7}Li(p,{alpha}){sup 4}He has been extracted together with its astrophysical factor S(E).

  2. Experiment and theory for the reaction 7Li(γ,t)4He for E/sub γ/<50 MeV

    Differential and total cross sections for the 7Li(γ,t)4He reaction were measured. Both real and virtual photons were used in the experiment and gave self-consistent results. The data show a broad resonance indicating the presence of positive parity states near 8 MeV excitation in 7Li. A calculation using an α-3H cluster model of 7Li was also performed. Poor agreement is found between the calculation and experimental results

  3. Nuclear magnetic response imaging of sap flow in plants

    Windt, C.W.

    2007-01-01

    This thesis deals with Nuclear Magnetic Resonance (NMR) imaging of long distance transport in plants. Long distance transport in plants is an enigmatic process. The theoretical framework that describes its basic properties has been in place for almost a century, yet at the same time only little is known about the dynamics of long distance transport inside the living plant. The latter is caused by the fact that the two pathways in which transport takes place, the xylem and the phloem, are virt...

  4. Nuclear magnetic resonance in LaNi/sub 5/

    Rubinstein, M.; Swartzendruber, L.J.; Bennett, L.H.

    1979-03-01

    Proton and La/sup 139/ nuclear magnetic resonance measurements have been performed on LaNi/sub 5/, LaNi/sub 5/ hydrides, and LaNi/sub 5/H/sub x/ with ternary additions. With ternary additions, the activation energy for proton diffusion remained unchanged, but the motionally narrowed linewidth broadened. The quadrupole interaction on the La site has been determined in LaNi/sub 5/ and LaNi/sub 5/H/sub x/.

  5. Science and history explored by nuclear magnetic resonance

    Baias, Maria Antoaneta

    2009-01-01

    Nuclear Magnetic Resonance was chosen as the main tool for investigating different biological and chemical systems, as it is unique in providing the information details about the morphology and molecular structures and conformations by which the fundamental properties of these biological and chemical systems can be understood. Proton spin-diffusion experiments combined with 13C CPMAS spectroscopy were successfully applied to characterize the changes that occur during the thermal denaturation ...

  6. Experimental Implementation of Remote State Preparation by Nuclear Magnetic Resonance

    Peng, Xinhua; Zhu, Xiwen; Fang, Ximing; Feng, Mang; Liu, Maili; Gao, Kelin

    2002-01-01

    We have experimentally implemented remote state preparation (RSP) of a qubit from a hydrogen to a carbon nucleus in molecules of carbon-13 labeled chloroform $^{13}$CHCl$_{3}$ over interatomic distances using liquid-state nuclear magnetic resonance (NMR) technique. Full RSP of a special ensemble of qubits, i.e., a qubit chosen from equatorial and polar great circles on a Bloch sphere with Pati's scheme, was achieved with one cbit communication. Such a RSP scheme can be generalized to prepare ...

  7. Experimental implementation of remote state preparation by nuclear magnetic resonance

    Peng Xinhua; Zhu Xiwen; Fang Ximing; Feng Mang; Liu Maili; Gao Kelin

    2003-01-13

    We have experimentally implemented remote state preparation of a qubit from a hydrogen to a carbon nucleus in molecules of carbon-13 labeled chloroform {sup 13}CHCl{sub 3} over interatomic distances using liquid-state nuclear magnetic resonance techniques. Full RSP of a special ensemble of qubits, i.e., a qubit chosen from either an equatorial or a polar great circle on a Bloch sphere with Pati's scheme, was achieved with one cbit communication.

  8. PWM high frequency oscillator in Nuclear Magnetic Resonance

    In this article we propose a new architecture for pulsed oscillator, in the area of radio frequency (RF), which operates with pulses of few microseconds in spectrometers of Nuclear Magnetic Resonance Pulsed. This new topology substitutes the classic amplifying systems with valves by field effect semiconductors of the type MOS-FET channel N, allowing a larger compacting and efficiency. This oscillator possibly reaching potencies of the order of 103 Watts at a low cost. (author)

  9. Optimal grouping for a nuclear magnetic resonance (NMR) scanner

    VANDAELE, Nico; VAN NIEUWENHUYSE, Inneke; CUPERS, Sascha

    2001-01-01

    In this paper we analyze how a Nuclear Magnetic Resonance Scanner can be managed more efficiently, simultaneously improving patient comfort (in terms of total time spent in the system) and increasing availability in case of emergency calls. By means of a superposition approach, all relevant data on the arrival and service process of different patient types are transformed into a general single server, single class queueing model. The objective function consists of the weighted average patient...

  10. Clinical applications of nuclear magnetic resonance spectroscopy: a review

    The advantages and present limitations of the clinical applications of nuclear magnetic resonance spectroscopy are reviewed in outline, with passing references to skeletal muscular studies, in particular a group of children with advanced Duchenne dystrophy, and the applications to the study of cerebral metabolism of neonates, excised kidneys, biopsy studies of breast and axillary lymph node samples, and NMR spectroscopy performed during chemotherapy of a secondary rhabdomyosarcoma in the skin. (U.K.)

  11. Nonadiabatic Geometric Angle in Nuclear Magnetic Resonance Connection

    Cherbal, Omar; Maamache, Mustapha; Drir, Mahrez

    2005-01-01

    By using the Grassmannian invariant-angle coherents states approach, the classical analogue of the Aharonov-Anandan nonadiabatic geometrical phase is found for a spin one-half in Nuclear Magnetic Resonance (NMR). In the adiabatic limit, the semi-classical relation between the adiabatic Berry’s phase and Hannay’s angle gives exactly the experimental result observed by Suter et al[12].

  12. A Comprehensive Theoretical Analysis of 6,7Li + 64Zn Elastic Scattering in a Wide Angular Range Around the Coulomb Barrier

    Ibraheem, Awad A.; Aygun, M.

    2016-08-01

    In this paper, the elastic scattering angular distributions of 6,7Li on 64Zn have been investigated by using various nuclear potentials. For this, we use the phenomenological Woods-Saxon potential, the real double folding potential with the density-independent M3Y effective interaction supplemented with an imaginary part in Woods-Saxon form and the double folding potentials multiplied with a normalization factor of the real and imaginary parts via the density-independent and CDM3Y6 density-dependent versions of the M3Y effective interaction have been used. The results have been compared with each other as well as with the experimental data. It has been observed that the agreement between the theoretical results and earlier reported data is perfect. Finally, the change of the total reaction cross sections with energy has been investigated.

  13. A Comprehensive Theoretical Analysis of 6,7Li + 64Zn Elastic Scattering in a Wide Angular Range Around the Coulomb Barrier

    Ibraheem, Awad A.; Aygun, M.

    2016-06-01

    In this paper, the elastic scattering angular distributions of 6,7Li on 64Zn have been investigated by using various nuclear potentials. For this, we use the phenomenological Woods-Saxon potential, the real double folding potential with the density-independent M3Y effective interaction supplemented with an imaginary part in Woods-Saxon form and the double folding potentials multiplied with a normalization factor of the real and imaginary parts via the density-independent and CDM3Y6 density-dependent versions of the M3Y effective interaction have been used. The results have been compared with each other as well as with the experimental data. It has been observed that the agreement between the theoretical results and earlier reported data is perfect. Finally, the change of the total reaction cross sections with energy has been investigated.

  14. Photoassociation and ionization spectroscopy of ultracold $^{7}$Li$^{85}$Rb molecules

    Altaf, Adeel; Lorenz, John; Pérez-Ríos, Jesús; Chen, Yong P; Elliott, D S

    2014-01-01

    We report spectroscopic studies of ultracold $^{7}$Li$^{85}$Rb molecules using multiphoton ionization detection. With our dual-species Li and Rb MOT apparatus, we create ultracold LiRb molecules via photoassociation (PA), and explore new PA resonances, with binding energies up to ~62 cm^{-1}. Furthermore, we measure the resonantly enhanced multiphoton ionization (REMPI) spectra as a probe of ground and excited state vibrational levels. We identify vibrational levels of the $a^{3}\\Sigma^{+} (v" = 7 - 13)$, $3^{3} \\Pi (v'_{\\Pi} = 0 - 10)$ and $4^{3} \\Sigma^{+} (v'_{\\Sigma} = 0 - 5)$ electronic states. Our line assignments agree well with ab initio calculations. These spectroscopic studies are crucial to discovering transition pathways for transferring ultracold LiRb molecules created via PA to deeply bound rovibrational levels of the electronic ground state.

  15. Host-guest interactions in fluorinated polymer electrolytes: A 7Li-13C NMR study

    Mustarelli, P.; Quartarone, E.; Capiglia, C.; Tomasi, C.; Ferloni, P.; Magistris, A.

    1999-08-01

    Gel-type electrolytes based on fluorinated polymers are of interest for electrochemical devices. We present a 7Li-13C solid-state NMR and modulated differential scanning calorimetry (MDSC) study of gel electrolytes based on a copolymer poly(vinylidene fluoride) (PVdF)-hexafluoropropylene (HFP) activated with a nonaqueous solution ethylene carbonate (EC)-propylene carbonate (PC)-LiN(CF3SO2)2. We show that the narrowing of the Li lineshape is decoupled from the glass transition. The behavior of the longitudinal relaxation times, T1, confirms that the host polymer matrix simply behaves like a quasiinert cage for the solution. These results are confirmed by 13C NMR at the magic angle (MAS) data, which show that the presence of the polymer does not significantly affect the chemical shift changes induced in the EC/PC carbons by the imide salt.

  16. Covariance analysis of n + 7Li data for ENDF/B-VI

    A new covariance analysis of n/plus/7Li experimental data has been completed for Version VI of ENDFB. The analysis basically updates our 1981 work for ENDFB-V.2 to include new data that has become available since that time and to incorporate cross correlations between different experiments. The bulk of the new measured data consists of some 10 new (or newly revised) tritium-production measurements involving about 70 new data points. The new analysis results in only small changes in the previous evaluation of the tritium-production cross section but significantly reduces the magnitudes of uncertainties due to the more extensive and accurate data base that was used

  17. New method to evaluate the 7Li(p, n)7Be reaction near threshold

    In this work a complete description of the 7Li(p, n)7Be reaction near threshold is given using center-of-mass and relative coordinates. It is shown that this standard approach, not used before in this context, leads to a simple mathematical representation which gives easy access to all relevant quantities in the reaction and allows a precise numerical implementation. It also allows in a simple way to include proton beam-energy spread affects. The method, implemented as a C++ code, was validated both with numerical and experimental data finding a good agreement. This tool is also used here to analyze scattered published measurements such as (p, n) cross sections, differential and total neutron yields for thick targets. Using these data we derive a consistent set of parameters to evaluate neutron production near threshold. Sensitivity of the results to data uncertainty and the possibility of incorporating new measurements are also discussed

  18. Dynamics of fragment capture for cluster structures of weakly bound 7Li

    Role of cluster structures of 7Li on reaction dynamics have been studied by performing exclusive measurements of prompt-γ rays from residues with scattered particles at energy, E/Vb = 1.6, with 198Pt target. Yields of the residues resulting after capture of t and 4,5,6He, corresponding to different excitation energies of the composite system were estimated. The results were compared with three body classical-dynamical model for breakup fusion, constrained by the measured fusion, α and t capture cross-sections. The cross-section of residues from capture of α and t agreed well with the prediction of the model showing dominance of the two step process - breakup fusion, while those from tightly bound 6He showed massive transfer to be the dominant mechanism. (authors)

  19. Beam shaping assembly optimization for 7Li(p,n)7Be accelerator based BNCT

    Within the framework of accelerator-based BNCT, a project to develop a folded Tandem-ElectroStatic-Quadrupole accelerator is under way at the Atomic Energy Commission of Argentina. The proposed accelerator is conceived to deliver a proton beam of 30 mA at about 2.5 MeV. In this work we explore a Beam Shaping Assembly (BSA) design based on the 7Li(p,n)7Be neutron production reaction to obtain neutron beams to treat deep seated tumors. - Highlights: • A Beam Shaping Assembly for accelerator based BNCT has been designed. • A conical port for easy patient positioning and the cooling system are included. • Several configurations can deliver tumor doses greater than 55 RBEGy. • Good tumor doses can be obtained in less than 60 min of irradiation time

  20. Charge and mass distribution in 7Li induced fission of 232Th

    Formation cross sections of about forty fission products have been determined using recoil catcher technique followed by off line gamma-ray spectrometry in 7Li induced fission of 232Th at Elab=41.9, 36.6 and 31.4 MeV. The measured data have been used to deduce charge and mass distributions. Mass distribution is found to be asymmetric at all the three energies. Cross sections of evaporation residues formed in both transfer reactions (232,233,234Pa) as well as in complete fusion (234Np), have also been measured. The measured evaporation residue cross sections and the decay probabilities of target like nuclei (233,234,235Pa) formed in the various transfer reactions, as calculated by PACE2, have been used to estimate the transfer induced fission cross sections. The data indicated that the magnitude of transfer induced fission is very small

  1. Dynamics of fragment capture for cluster structures of weakly bound 7Li

    Shrivastava A.

    2013-12-01

    Full Text Available Role of cluster structures of 7Li on reaction dynamics have been studied by performing exclusive measurements of prompt-γ rays from residues with scattered particles at energy, E/Vb = 1.6, with 198Pt target. Yields of the residues resulting after capture of t and 4,5,6He, corresponding to different excitation energies of the composite system were estimated. The results were compared with three body classical-dynamical model for breakup fusion, constrained by the measured fusion, α and t capture cross-sections. The cross-section of residues from capture of α and t agreed well with the prediction of the model showing dominance of the two step process - breakup fusion, while those from tightly bound 6He showed massive transfer to be the dominant mechanism.

  2. Rate of 3H(7Li,n0)9Be and big-bang nucleosynthesis

    The differential cross sections for the 3H(7Li,n0)9Be reaction measured at 5 angles in the energy range E(c.m.)=0.2-0.9 MeV using a pulsed 7Li beam and time-of-flight technique. Absolute values of the cross section were obtained by comparison with the well-known cross section of 3H(d,n)4He at Ed=1.0 MeV. The resulting reaction rates are obtained at temperatures relevant to big-bang nucleosynthesis, and consequences for primordial 9Be abundances are discussed. (orig.)

  3. The reaction 7Li(e,3H)4He,e' between 6 and 15 MeV

    Tritons resulting from the electrodisintegration of 7Li have been measured at 90 deg for an incident electron energy of 23.8 MeV over an energy range which ensured that only tritons emitted in the two-body channel were detected. The electrodisintegration cross sections were converted to equivalent photodisintegration data and compared to earlier results. Large discrepancies are observed. It is found that the (γ,3H) channel contributes appreciably to the electric dipole sum rule for 7Li. (author)

  4. Asymptotic and near-target direct breakup of 6Li and 7Li

    Kalkal, Sunil; Simpson, E. C.; Luong, D. H.; Cook, K. J.; Dasgupta, M.; Hinde, D. J.; Carter, I. P.; Jeung, D. Y.; Mohanto, G.; Palshetkar, C. S.; Prasad, E.; Rafferty, D. C.; Simenel, C.; Vo-Phuoc, K.; Williams, E.; Gasques, L. R.; Gomes, P. R. S.; Linares, R.

    2016-04-01

    Background: Li,76 and 9Be are weakly bound against breakup into their cluster constituents. Breakup location is important for determining the role of breakup in above-barrier complete fusion suppression. Recent works have pointed out that experimental observables can be used to separate near-target and asymptotic breakup. Purpose: Our purpose is to distinguish near-target and asymptotic direct breakup of Li,76 in reactions with nuclei in different mass regions. Method: Charged particle coincidence measurements are carried out with pulsed Li,76 beams on 58Ni and 64Zn targets at sub-barrier energies and compared with previous measurements using 208Pb and 209Bi targets. A detector array providing a large angular coverage is used, along with time-of-flight information to give definitive particle identification of the direct breakup fragments. Results: In interactions of 6Li with 58Ni and 64Zn, direct breakup occurs only asymptotically far away from the target. However, in interactions with 208Pb and 209Bi, near-target breakup occurs in addition to asymptotic breakup. Direct breakup of 7Li into α -t is not observed in interactions with 58Ni and 64Zn. However, near-target dominated direct breakup was observed in measurements with 208Pb and 209Bi. A modified version of the Monte Carlo classical trajectory model code platypus, which explicitly takes into account lifetimes associated with unbound states, is used to simulate sub-barrier breakup reactions. Conclusions: Near-target breakup in interactions with Li,76 is an important mechanism only for the heavy targets 208Pb and 209Bi. There is insignificant near-target direct breakup of 6Li and no direct breakup of 7Li in reactions with 58Ni and 64Zn. Therefore, direct breakup is unlikely to suppress the above-barrier fusion cross section in reactions of Li,76 with 58Ni and 64Zn nuclei.

  5. Fast neutron measurements with 7Li and 6Li enriched CLYC scintillators

    Giaz, A.; Blasi, N.; Boiano, C.; Brambilla, S.; Camera, F.; Cattadori, C.; Ceruti, S.; Gramegna, F.; Marchi, T.; Mattei, I.; Mentana, A.; Million, B.; Pellegri, L.; Rebai, M.; Riboldi, S.; Salamida, F.; Tardocchi, M.

    2016-07-01

    The recently developed Cs2LiYCl6:Ce (CLYC) crystals are interesting scintillation detectors not only for their gamma energy resolution (neutrons. The thermal neutrons were detected by the 6Li(n,α)t reaction while for the fast neutrons the 35Cl(n,p)35S and 35Cl(n,α)32P neutron-capture reactions were exploited. The energy of the outgoing proton or α particle scales linearly with the incident neutron energy. The kinetic energy of the fast neutrons can be measured using both the Time Of Flight (TOF) technique and using the CLYC energy signal. In this work, the response to monochromatic fast neutrons (1.9-3.8 MeV) of two CLYC 1″×1″ crystals was measured using both the TOF and the energy signal. The observables were combined to identify fast neutrons, to subtract the thermal neutron background and to identify different fast neutron-capture reactions on 35Cl, in other words to understand if the detected particle is an α or a proton. We performed a dedicated measurement at the CN accelerator facility of the INFN Legnaro National Laboratories (Italy), where the fast neutrons were produced by impinging a proton beam (4.5, 5.0 and 5.5 MeV) on a 7LiF target. We tested a CLYC detector 6Li-enriched at about 95%, which is ideal for thermal neutron measurements, in parallel with another CLYC detector 7Li-enriched at more than 99%, which is suitable for fast neutron measurements.

  6. Magnetic Flux Compression Concept for Nuclear Pulse Propulsion and Power

    Litchford, Ronald J.

    2000-01-01

    The desire for fast, efficient interplanetary transport requires propulsion systems having short acceleration times and very high specific impulse attributes. Unfortunately, most highly efficient propulsion systems which are within the capabilities of present day technologies are either very heavy or yield very low impulse such that the acceleration time to final velocity is too long to be of lasting interest, One exception, the nuclear thermal thruster, could achieve the desired acceleration but it would require inordinately large mass ratios to reach the range of desired final velocities. An alternative approach, among several competing concepts that are beyond our modern technical capabilities, is a pulsed thermonuclear device utilizing microfusion detonations. In this paper, we examine the feasibility of an innovative magnetic flux compression concept for utilizing microfusion detonations, assuming that such low yield nuclear bursts can be realized in practice. In this concept, a magnetic field is compressed between an expanding detonation driven diamagnetic plasma and a stationary structure formed from a high temperature superconductor (HTSC). In general, we are interested in accomplishing two important functions: (1) collimation of a hot diamagnetic plasma for direct thrust production; and (2) pulse power generation for dense plasma ignition. For the purposes of this research, it is assumed that rnicrofusion detonation technology may become available within a few decades, and that this approach could capitalize on recent advances in inertial confinement fusion ICF) technologies including magnetized target concepts and antimatter initiated nuclear detonations. The charged particle expansion velocity in these detonations can be on the order of 10 (exp 6)- 10 (exp 7) meters per second, and, if effectively collimated by a magnetic nozzle, can yield the Isp and the acceleration levels needed for practical interplanetary spaceflight. The ability to ignite pure

  7. Quantitative velocity distributions via nuclear magnetic resonance flow metering

    O'Neill, Keelan T.; Fridjonsson, Einar O.; Stanwix, Paul L.; Johns, Michael L.

    2016-08-01

    We demonstrate the use of Tikhonov regularisation as a data inversion technique to determine the velocity distributions of flowing liquid streams. Regularisation is applied to the signal produced by a nuclear magnetic resonance (NMR) flow measurement system consisting of a pre-polarising permanent magnet located upstream of an Earth's magnetic field NMR detection coil. A simple free induction decay (FID) NMR signal is measured for the flowing stream in what is effectively a 'time-of-flight' measurement. The FID signal is then modelled as a function of fluid velocity and acquisition time, enabling determination of the velocity probability distributions via regularisation. The mean values of these velocity distributions were successfully validated against in-line rotameters. The ability to quantify multi-modal velocity distributions was also demonstrated using a two-pipe system.

  8. Parahydrogen enhanced zero-field nuclear magnetic resonance

    Theis, Thomas; Kervern, Gwendal; Knappe, Svenja; Kitching, John; Ledbetter, Micah; Budker, Dmitry; Pines, Alex

    2011-01-01

    Nuclear magnetic resonance (NMR), conventionally detected in multi-tesla magnetic fields, is a powerful analytical tool for the determination of molecular identity, structure, and function. With the advent of prepolarization methods and alternative detection schemes using atomic magnetometers or superconducting quantum interference devices (SQUIDs), NMR in very low- (~earth's field), and even zero-field, has recently attracted considerable attention. Despite the use of SQUIDs or atomic magnetometers, low-field NMR typically suffers from low sensitivity compared to conventional high-field NMR. Here we demonstrate direct detection of zero-field NMR signals generated via parahydrogen induced polarization (PHIP), enabling high-resolution NMR without the use of any magnets. The sensitivity is sufficient to observe spectra exhibiting 13C-1H J-couplings in compounds with 13C in natural abundance in a single transient. The resulting spectra display distinct features that have straightforward interpretation and can be...

  9. Imaging using long range dipolar field effects Nuclear magnetic resonance

    Gutteridge, S

    2002-01-01

    The work in this thesis has been undertaken by the except where indicated in reference, within the Magnetic Resonance Centre, at the University of Nottingham during the period from October 1998 to March 2001. This thesis details the different characteristics of the long range dipolar field and its application to magnetic resonance imaging. The long range dipolar field is usually neglected in nuclear magnetic resonance experiments, as molecular tumbling decouples its effect at short distances. However, in highly polarised samples residual long range components have a significant effect on the evolution of the magnetisation, giving rise to multiple spin echoes and unexpected quantum coherences. Three applications utilising these dipolar field effects are documented in this thesis. The first demonstrates the spatial sensitivity of the signal generated via dipolar field effects in structured liquid state samples. The second utilises the signal produced by the dipolar field to create proton spin density maps. Thes...

  10. Design and construction of a nuclear magnetic resonator circuit

    It is described the operation of a feedback circuit that it using the nuclear resonance phenomena and that covers a broad sweeping interval in frequency with a minimum adjustment of the circuit elements and it produces an appropriate nuclear absorption for a sign relation at reasonable noise. The circuit is an oscillator amplifier modulated that it is based its sensibility and stability in an inductive-capacitive arrangement in parallel and always operate in resonant condition, in such a way that the quality factor of Q arrangement has been very elevated. Thus when the nuclear absorption occurs it is producing a fall of Q effective. The oscillation amplitude is controllable and it maintains in a convenient value over the operation interval using control by feedback. The circuit uses a configuration 'Auto dyne Hop kin' that it suffers as a follower of inductive charge, which have the main characteristic of to cause a negative resistance that it appears through the tuning circuit. It is introduced a control for feedback via two trajectories, the first by differential pair for to maintain the amplitude level in RF and the second for to stability a band wide interval in the modulation condition. It is necessary since the RF signal value must have a value to excite the specimen nucleus without to carry to saturate it and that the permanence in the absorption region was appropriate. Between applications of the nuclear magnetic resonance phenomena we have the magnetic fields measurements, physicochemical molecular properties studies, training and medical instrumentation. (Author)

  11. Nuclear magnetic and electric dipole moments of neon-19

    This thesis presents a detailed discussion of a series of experiments designed to measure the magnetic and electric dipole moments of the β-emitting nucleus 19Ne. The 19Ne is generated in the reaction 19F(p,n)19Ne and is polarized by a ''stern-Gerlach'' magnet in a rare gas atomic beams machine. The atoms are stored in a cell for many seconds without depolarizing. The parity violating asymmetry in the β angular distribution is used to monitor the nuclear polarization. The polarized atoms are stored in a cell in a uniform magnetic field. The β-asymmetry is monitored by a pair of β-detectors located on either side of the cell. Transitions between the M/sub J/ = +1/2 and M/sub J/ = -1/2 spin states are induced by an rf field generated by a small Helmholtz coil pair surrounding the cell. Nuclear magnetic resonance lines are observed and the magnetic moment of 19Ne measured to be μ(19Ne) = -1.88542(8)μ/sub N/. A new magnet, cell and detectors were designed to give narrow resonance lines. The equipment is described in detail and several resonance line shapes are discussed. The narrowest resonance line achieved with this system was 0.043 Hz FWHM. This width is primarily due to the 19Ne lifetime. Pulsed NMR lineshapes were also observed. The narrow NMR lines observed in the previous experiment were then used as a probe to look for an electric dipole moment (EDM) in 19Ne. Any shift in the resonance frequency correlated with changes in an externally applied electric field would be evidence for an EDM. The EDM of the 19Ne atom was measured to (7.2 +/- 6.2 X 10-22 e-cm. This experiment and possible improvements are discussed in detail

  12. Nuclear magnetic resonance study of metallic scandium chlorides

    The 45Sc nuclear magnetic resonance was studied in samples having the general composition CsSc/sub x/Cl3 (0.67 less than or equal to x less than or equal to 1.0) in the CsCl-ScCl3-Sc system. In particular the structure of CsScCl3 suggests that it may be a one-dimensional conductor, and an attempt was therefore made to detect the occurrence of a metal-insulator transition of the type characteristic of one-dimensional conductors. Conventional crossed-coil (nuclear induction) techniques were employed. The 45Sc resonance was studied over a wide frequency range (4 to 24 MHz) at 300K, these measurements yielding the Knight shift and nuclear electric quadrupole coupling parameters. No significant variation in the spectra occurred from 4.2K to 450K, indicating the absence of a metal-insulator transition in this temperature range

  13. Analysis of ringing due to magnetic core materials used in pulsed nuclear magnetic resonance applications

    Prabhu Gaunkar, Neelam; Nlebedim, Cajetan; Hadimani, Ravi; Bulu, Irfan; Song, Yi-Qiao; Mina, Mani; Jiles, David

    Oil-field well logging instruments employ pulsed nuclear magnetic resonance (NMR) techniques and use inductive sensors to detect and evaluate the presence of particular fluids in geological formations. Acting as both signal transmitters and receivers most inductive sensors employ magnetic cores to enhance the quality and amplitude of signals recorded during field measurements. It is observed that the magnetic core also responds to the applied input signal thereby generating a signal (`ringing') that interferes with the measurement of the signals from the target formations. This causes significant noise and receiver dead time and it is beneficial to eliminate/suppress the signals received from the magnetic core. In this work a detailed analysis of the magnetic core response and in particular loading of the sensor due to the presence of the magnetic core is presented. Pulsed NMR measurements over a frequency band of 100 kHz to 1MHz are used to determine the amplitude and linewidth of the signals acquired from different magnetic core materials. A lower signal amplitude and a higher linewidth are vital since these would correspond to minimal contributions from the magnetic core to the inductive sensor response and thus leading to minimized receiver dead time.

  14. Transformation of Symmetrization Order to Nuclear-Spin Magnetization by Chemical Reaction and Nuclear Magnetic Resonance

    Bowers, C. Russell; Weitekamp, Daniel P.

    1986-01-01

    A method of obtaining very large nuclear-spin polarizations is proposed and illustrated by density-operator calculations. The prediction is that chemical reaction and rf irradiation can convert the scalar parahydrogen state into polarization of order unity on the nuclear spins of the products of molecular-hydrogen addition reactions. A means of extending the resultant sensitivity enhancement to other spins is proposed in which the transfer of order occurs through population differences not as...

  15. Detection of molecules and cells using nuclear magnetic resonance with magnetic nanoparticles

    For the detection of small molecules, proteins or even cells in vitro, functionalised magnetic nanoparticles and nuclear magnetic resonance measurements can be applied. In this work, magnetic nanoparticles with the size of 5–7 nm were functionalised with antibodies to detect two model systems of different sizes, the protein avidin and Saccharomyces cerevisiae as the model organism. The synthesised magnetic nanoparticles showed a narrow size distribution, which was determined using transmission electron microscopy and dynamic light scattering. The magnetic nanoparticles were functionalised with the according antibodies via EDC/NHS chemistry. The binding of the antigen to magnetic nanoparticles was detected through the change in the NMR T2 relaxation time at 0.5 T (≈21.7 MHz). In case of a specific binding the particles cluster and the T2 relaxation time of the sample changes. The detection limit in buffer for FITC-avidin was determined to be 1.35 nM and 107 cells/ml for S. cerevisiae. For fluorescent microscopy the avidin molecules were labelled with FITC and for the detection of S. cerevisiae the magnetic nanoparticles were additionally functionalised with rhodamine. The binding of the particles to S. cerevisiae and the resulting clustering was also seen by transmission electron microscopy

  16. Detection of molecules and cells using nuclear magnetic resonance with magnetic nanoparticles

    Rümenapp, Christine, E-mail: ruemenapp@tum.de [Zentralinstitut für Medizintechnik (IMETUM), Technische Universität München, Garching (Germany); Gleich, Bernhard [Zentralinstitut für Medizintechnik (IMETUM), Technische Universität München, Garching (Germany); Mannherz, Hans Georg [Abteilung für Anatomie und Molekulare Embryologie, Ruhr Universität Bochum, Bochum (Germany); Haase, Axel [Zentralinstitut für Medizintechnik (IMETUM), Technische Universität München, Garching (Germany)

    2015-04-15

    For the detection of small molecules, proteins or even cells in vitro, functionalised magnetic nanoparticles and nuclear magnetic resonance measurements can be applied. In this work, magnetic nanoparticles with the size of 5–7 nm were functionalised with antibodies to detect two model systems of different sizes, the protein avidin and Saccharomyces cerevisiae as the model organism. The synthesised magnetic nanoparticles showed a narrow size distribution, which was determined using transmission electron microscopy and dynamic light scattering. The magnetic nanoparticles were functionalised with the according antibodies via EDC/NHS chemistry. The binding of the antigen to magnetic nanoparticles was detected through the change in the NMR T{sub 2} relaxation time at 0.5 T (≈21.7 MHz). In case of a specific binding the particles cluster and the T{sub 2} relaxation time of the sample changes. The detection limit in buffer for FITC-avidin was determined to be 1.35 nM and 10{sup 7} cells/ml for S. cerevisiae. For fluorescent microscopy the avidin molecules were labelled with FITC and for the detection of S. cerevisiae the magnetic nanoparticles were additionally functionalised with rhodamine. The binding of the particles to S. cerevisiae and the resulting clustering was also seen by transmission electron microscopy.

  17. On the hyperfine structures of the ground state(s) in the ${}^{6}$Li and ${}^{7}$Li atoms

    Frolov, Alexei M

    2016-01-01

    Hyperfine structure of the ground $2^{2}S-$states of the three-electron atoms and ions is investigated. By using our recent numerical values for the doublet electron density at the atomic nucleus we determine the hyperfine structure of the ground (doublet) $2^{2}S-$state(s) in the ${}^{6}$Li and ${}^{7}$Li atoms.

  18. About the reactions 3H(alpha,gamma)7Li and 3He(alpha,gamma)7Be

    In this article the current experimental and theoretical status of the radiative alpha capture reactions 3H(α,γ)7Li and 3He(α,γ)7Be and their relations to primordial nucleosynthesis and the solar neutrino problem are reviewed. (author)

  19. The value of B(E2;3/2- → 1/2-) for 7Li

    Previous experimental information from the Coulomb excitation of the 1/2- first excited state of 7Li is discussed and reanalysed, giving B(E2;3/2- → 1/2-) = 7.59 ± 0.10e2fm4. 28 refs., 3 tabs., 1 fig

  20. The α-continuum from the interaction of 70 MeV polarized 7Li with 54Fe

    The first- and second-rank analysing powers were measured for the α-particle continuum from the interaction of 70 MeV polarized 7Li with 54Fe. The data are consistent with a partial fusion reaction mechanism as the dominant process and can be described by a semiclassical model of analysing powers in transfer reactions. (author)

  1. Rotating-frame gradient fields for magnetic resonance imaging and nuclear magnetic resonance in low fields

    Bouchard, Louis-Serge; Pines, Alexander; Demas, Vasiliki

    2014-01-21

    A system and method for Fourier encoding a nuclear magnetic resonance (NMR) signal is disclosed. A static magnetic field B.sub.0 is provided along a first direction. An NMR signal from the sample is Fourier encoded by applying a rotating-frame gradient field B.sub.G superimposed on the B.sub.0, where the B.sub.G comprises a vector component rotating in a plane perpendicular to the first direction at an angular frequency .omega.in a laboratory frame. The Fourier-encoded NMR signal is detected.

  2. Coulomb interaction effects in many-particle nuclear reactions with two-fragment resonance formation

    The modified final-state interaction theory taking into consideration the Coulomb interaction between two-fragment nuclear resonance decay products and accompanying reaction products is developed including the case of near-threshold resonances. The branching ratio change is also studied for the near-threshold resonance 7Li*(Ex = 7.45 MeV), which is formed in the reaction 7Li(α,α)7Li*at Eα = 27.2 MeV

  3. Analysis of the transient response of nuclear spins in GaAs with/without nuclear magnetic resonance

    Rasly, Mahmoud; Lin, Zhichao; Yamamoto, Masafumi; Uemura, Tetsuya

    2016-05-01

    As an alternative to studying the steady-state responses of nuclear spins in solid state systems, working within a transient-state framework can reveal interesting phenomena. The response of nuclear spins in GaAs to a changing magnetic field was analyzed based on the time evolution of nuclear spin temperature. Simulation results well reproduced our experimental results for the transient oblique Hanle signals observed in an all-electrical spin injection device. The analysis showed that the so called dynamic nuclear polarization can be treated as a cooling tool for the nuclear spins: It works as a provider to exchange spin angular momentum between polarized electron spins and nuclear spins through the hyperfine interaction, leading to an increase in the nuclear polarization. In addition, a time-delay of the nuclear spin temperature with a fast sweep of the external magnetic field produces a possible transient state for the nuclear spin polarization. On the other hand, the nuclear magnetic resonance acts as a heating tool for a nuclear spin system. This causes the nuclear spin temperature to jump to infinity: i.e., the average nuclear spins along with the nuclear field vanish at resonant fields of 75As, 69Ga and 71Ga, showing an interesting step-dip structure in the oblique Hanle signals. These analyses provide a quantitative understanding of nuclear spin dynamics in semiconductors for application in future computation processing.

  4. 2.3 Tomography using nuclear magnetic resonance

    The use of nuclear magnetic resonance (NMR) not only allows the tomographic imaging of tissues but also the identification of the biochemical structure of tissues. The principles of the method are described as is a NMR examination unit based on a giant magnet with a central opening in which is placed the patient. The application of the said method allows to distinguish in the skull structures 2 mm in size, in the trunk 3 mm in size. The morphological image may be obtained in 2 mins, data on chemical composition in 7 mins. The method may be applied for diagnosing edemas of the brain, hematomas, for distinguishing benign and malignant tumours, for measuring blood vessel flow and for monitoring biochemical processes. The advantage of the method is that it does not load the patient with radioactive radiation. (J.P.)

  5. Nuclear spin relaxation in systems of magnetic spheres

    A new approach to the NMR relaxation theory for a system of magnetic spheres (sufficiently big spherical molecules) is presented. In this paper the NMR spin-lattice relaxation time T1 and spin-spin relaxation time T2 are calculated for nuclear spins I→j, taking into account intermolecular dipole-dipole interactions between the spins I→j, and spins S→k in the magnetic spheres. By an expansion of the dipole-dipole interaction in a series of spherical harmonics, it is possible to separate spatial variables of the interacting spins in a laboratory frame. A simultaneous effect of isotropic rotational and translation diffusion of the spins and relaxation rate of spins S→k is also taken into account

  6. Nuclear magnetic resonance force microscopy with a microwire rf source

    The authors use a 1.0 μm wide patterned Cu wire with an integrated nanomagnetic tip to measure the statistical nuclear polarization of 19F in CaF2 by magnetic resonance force microscopy. With less than 350 μW of dissipated power, the authors achieve rf magnetic fields over 4 mT at 115 MHz for a sample positioned within 100 nm of the 'microwire' rf source. A 200 nm diameter FeCo tip integrated onto the wire produces field gradients greater than 105 T/m at the same position. The large rf fields from the broadband microwire enable long rotating-frame spin lifetimes of up to 15 s at 4 K

  7. Nuclear Magnetic Resonance with the Distant Dipolar Field

    Corum, C A

    2005-01-01

    Distant dipolar field (DDF)-based nuclear magnetic resonance is an active research area with many fundamental properties still not well understood. Already several intriguing applications have developed, like HOMOGENIZED and IDEAL spectroscopy, that allow high resolution spectra to be obtained in inhomogeneous fields, such as in-vivo. The theoretical and experimental research in this thesis concentrates on the fundamental signal properties of DDF-based sequences in the presence of relaxation (T1 and T2) and diffusion. A general introduction to magnetic resonance phenomenon is followed by a more in depth introduction to the DDF and its effects. A novel analytical signal equation has been developed to describe the effects of T2 relaxation and diffusing spatially modulated longitudinal spins during the signal build period of an HOMOGENIZED cross peak. Diffusion of the longitudinal spins results in a lengthening of the effective dipolar demagnetization time, delaying the re-phasing of coupled anti-phase states in...

  8. A personal computer-based nuclear magnetic resonance spectrometer

    Job, Constantin; Pearson, Robert M.; Brown, Michael F.

    1994-11-01

    Nuclear magnetic resonance (NMR) spectroscopy using personal computer-based hardware has the potential of enabling the application of NMR methods to fields where conventional state of the art equipment is either impractical or too costly. With such a strategy for data acquisition and processing, disciplines including civil engineering, agriculture, geology, archaeology, and others have the possibility of utilizing magnetic resonance techniques within the laboratory or conducting applications directly in the field. Another aspect is the possibility of utilizing existing NMR magnets which may be in good condition but unused because of outdated or nonrepairable electronics. Moreover, NMR applications based on personal computer technology may open up teaching possibilities at the college or even secondary school level. The goal of developing such a personal computer (PC)-based NMR standard is facilitated by existing technologies including logic cell arrays, direct digital frequency synthesis, use of PC-based electrical engineering software tools to fabricate electronic circuits, and the use of permanent magnets based on neodymium-iron-boron alloy. Utilizing such an approach, we have been able to place essentially an entire NMR spectrometer console on two printed circuit boards, with the exception of the receiver and radio frequency power amplifier. Future upgrades to include the deuterium lock and the decoupler unit are readily envisioned. The continued development of such PC-based NMR spectrometers is expected to benefit from the fast growing, practical, and low cost personal computer market.

  9. On the quantumness of correlations in nuclear magnetic resonance

    Soares-Pinto, D O; Maziero, J; Gavini-Viana, A; Serra, R M; Céleri, L C

    2012-01-01

    Nuclear Magnetic Resonance (NMR) was successfully employed to test several protocols and ideas in Quantum Information Science. In most of these implementations the existence of entanglement was ruled out. This fact introduced concerns and questions about the quantum nature of such bench tests. In this article we address some issues related to the non-classical aspects of NMR systems. We discuss some experiments where the quantum aspects of this system are supported by quantum correlations of separable states. Such quantumness, beyond the entanglement-separability paradigm, is revealed via a departure between the quantum and the classical versions of information theory. In this scenario, the concept of quantum discord seems to play an important role. We also present an experimental implementation of an analogous of the single-photon Mach-Zehnder interferometer employing two nuclear spins to encode the interferometric paths. This experiment illustrate how non-classical correlations of separable states may be us...

  10. Implementation of Quantum Private Queries Using Nuclear Magnetic Resonance

    WANG Chuan; HAO Liang; ZHAO Lian-Jie

    2011-01-01

    @@ We present a modified protocol for the realization of a quantum private query process on a classical database.Using one-qubit query and CNOT operation,the query process can be realized in a two-mode database.In the query process,the data privacy is preserved as the sender would not reveal any information about the database besides her query information,and the database provider cannot retain any information about the query.We implement the quantum private query protocol in a nuclear magnetic resonance system.The density matrix of the memory registers are constructed.