Science.gov

Sample records for gamma nuclear resonance

  1. The Science of Nuclear Materials Detection using gamma-ray beams: Nuclear Resonance Fluorescence

    NASA Astrophysics Data System (ADS)

    Ohgaki, Hideaki

    2014-09-01

    An atomic nucleus is excited by absorption of incident photons with an energy the same as the excitation energy of the level, and subsequently a gamma-ray is emitted as it de-excites. This phenomenon is called Nuclear Resonance Fluorescence and mostly used for studies on Nuclear Physics field. By measuring the NRF gamma-rays, we can identify nuclear species in any materials because the energies of the NRF gamma-rays uniquely depend on the nuclear species. For example, 235U has an excitation level at 1733 keV. If we irradiate a material including 235U with a gamma-ray tuned at this excitation level, the material absorbs the gamma-ray and re-emits another gamma-ray immediately to move back towards the ground state. Therefore we can detect the 235U by measuring the re-emitted (NRF) gamma-rays. Several inspection methods using gamma-rays, which can penetrate a thick shielding have been proposed and examined. Bertozzi and Ledoux have proposed an application of nuclear resonance fluorescence (NRF) by using bremsstrahlung radiations. However the signal-to-noise (SN) ratio of the NRF measurement with the bremsstrahlung radiation is, in general, low. Only a part of the incident photons makes NRF with a narrow resonant band (meV-eV) whereas most of incident radiation is scattered by atomic processes in which the reaction rate is higher than that of NRF by several orders of magnitudes and causes a background. Thus, the NRF with a gamma-ray quasi-monochromatic radiation beam is proposed. The monochromatic gamma-rays are generated by using laser Compton scattering (LCS) of electrons and intense laser photons by putting a collimator to restrict the gamma-ray divergence downstream. The LCS gamma-ray, which is energy-tunable and monochromatic, is an optimum apparatus for NRF measurements We have been conducted NRF experiment for nuclear research, especially with high linear polarized gamma-ray generated by LCS, to survey the distribution of M1 strength in MeV region in LCS

  2. The nuclear resonance scattering calibration technique for the EuroGammaS gamma characterisation system at ELI-NP-GBS

    NASA Astrophysics Data System (ADS)

    Pellegriti, M. G.; Albergo, S.; Adriani, O.; Andreotti, M.; Berto, D.; Borgheresi, R.; Cappello, G.; Cardarelli, P.; Consoli, E.; Di Domenico, G.; Evangelisti, F.; Gambaccini, M.; Graziani, G.; Lenzi, M.; Marziani, M.; Palumbo, L.; Passaleva, G.; Paternò, G.; Serban, A.; Squerzanti, S.; Starodubtsev, O.; Tricomi, A.; Variola, A.; Veltri, M.; Zerbo, B.

    2017-03-01

    A Gamma Beam System (GBS), designed by the EuroGammaS collaboration, will be implemented for the ELI-NP facility in Magurele, Romania. The facility will deliver an intense gamma beam, obtained by collimatio of the emerging radiation from inverse Compton interaction. Gamma beam energy range will span from 0.2 up to 19.5 MeV with unprecedented performances in terms of brilliance, photon flux and energy bandwidth. For the characterisation of the gamma beam during the commissioning and normal operation, a full detection system has been designed to measure energy spectrum, beam intensity, space and time profiles. The gamma-beam characterisation system consists of four elements: a Compton spectrometer, to measure and monitor the photon energy spectrum, in particular the energy bandwidth; a sampling calorimeter, for a fast combined measurement of the beam average energy and its intensity; a nuclear resonant scattering spectrometer, for absolute beam energy calibration and inter-calibration of the other detector elements; and finally a beam profile imager to be used for alignment and diagnostics purposes. In this paper, a general overview of the ELI-NP gamma characterisation system will be given and the NRSS system will be in particular discussed.

  3. Resonance production in. gamma gamma. collisions

    SciTech Connect

    Renard, F.M.

    1983-04-01

    The processes ..gamma gamma.. ..-->.. hadrons can be depicted as follows. One photon creates a q anti q pair which starts to evolve; the other photon can either (A) make its own q anti q pair and the (q anti q q anti q) system continue to evolve or (B) interact with the quarks of the first pair and lead to a modified (q anti q) system in interaction with C = +1 quantum numbers. A review of the recent theoretical activity concerning resonance production and related problems is given under the following headings: hadronic C = +1 spectroscopy (q anti q, qq anti q anti q, q anti q g, gg, ggg bound states and mixing effects); exclusive ..gamma gamma.. processes (generalities, unitarized Born method, VDM and QCD); total cross section (soft and hard contributions); q/sup 2/ dependence of soft processes (soft/hard separation, 1/sup +- +/ resonances); and polarization effects. (WHK)

  4. The effects of proton-beam quality on the production of gamma rays for nuclear resonance absorption in nitrogen

    SciTech Connect

    Graybill, R.; Morgado, R.E.; Cappiello, C.C.

    1994-05-01

    The authors describe a method for performing nuclear-resonance absorption with the proton beam from a radio-frequency quadrupole (RFQ) linear accelerator. The objective was to assess the suitability of the pulsed beam from an RFQ to image nitrogen compared to electrostatic accelerators. This choice of accelerator results in trade-offs in performance and complexity, in return for the prospect of higher average current. In spite of a reduced resonance attenuation coefficient in nitrogen, they successfully produced three-dimensional tomographic images of real explosives in luggage the first time the unoptimized system was operated. The results and assessments of the initial laboratory measurements are reported.

  5. Nuclear magnetic resonance gyroscope

    SciTech Connect

    Grover, B.C.

    1984-02-07

    A nuclear magnetic resonance gyro using two nuclear magnetic resonance gases, preferably xenon 129 and xenon 131, together with two alkaline metal vapors, preferably rubidium, potassium or cesium, one of the two alkaline metal vapors being pumped by light which has the wavelength of that alkaline metal vapor, and the other alkaline vapor being illuminated by light which has the wavelength of that other alkaline vapor.

  6. Monte Carlo simulation of dose distribution in water around 57Fe3O4 magnetite nanoparticle in the nuclear gamma resonance condition

    NASA Astrophysics Data System (ADS)

    Gabbasov, R.; Polikarpov, M.; Safronov, V.; Sozontov, E.; Yurenya, A.; Panchenko, V.

    2016-12-01

    In this work was proposed a new radiotherapy enhancement method consisting of the administration of magnetic nanoparticles into the cells with further irradiation with a gamma-ray beam. As a result, adjusting the energy distribution of a gamma-ray beam and 57Fe abundance it is possible to achieve an extremely intensive electron emission because of a nuclear resonance. The produced conversion and Auger electrons can be used as an effective tool for DNA lesions production. We developed a Monte Carlo model for an electron and gamma emission by 57Fe nucleus using the Geant4 program package. The parameters of a resonant absorption were taken from Mössbauer spectra of magnetite nanoparticles synthesized for the administration into live cells. The space distribution of the radiation dose showed an increase in the dose of 2-2.5 times in the case of the natural abundance and more than 50 times in the case of the 66 % enrichment of the nanoparticles.

  7. Nuclear Magnetic Resonance Gyroscope

    NASA Astrophysics Data System (ADS)

    Bulatowicz, Michael; Griffith, Robert; Larsen, Michael

    2014-03-01

    The navigation grade micro Nuclear Magnetic Resonance Gyroscope (micro-NMRG) being developed by the Northrop Grumman Corporation (NGC) has concluded the fourth and final phase of the DARPA Navigation Grade Integrated Micro Gyro (NGIMG) program. Traditional MEMS gyros utilize springs as an inherent part of the sensing mechanism, leading to bias and scale factor sensitivity to acceleration and vibration. As a result, they have not met performance expectations in real world environments and to date have been limited to tactical grade applications. The Nuclear Magnetic Resonance Gyroscope (NMRG) utilizes the fixed precession rate of a nuclear spin in a constant magnetic field as an inertial reference for determining rotation. The nuclear spin precession rate sensitivity to acceleration and vibration is negligible for most applications. Therefore, the application of new micro and batch fabrication methods to NMRG technology holds great promise for navigation grade performance in a low cost and compact gyro. This poster will describe the history, operational principles, design, and demonstrated performance of the NMRG including an overview of the NGC designs developed and demonstrated in the DARPA gyro development program.

  8. Nuclear Magnetic Resonance Gyroscope

    NASA Astrophysics Data System (ADS)

    Bulatowicz, Michael; Clark, Philip; Griffith, Robert; Larsen, Michael; Mirijanian, James

    2012-06-01

    The navigation grade micro Nuclear Magnetic Resonance Gyroscope (micro-NMRG) being developed by the Northrop Grumman Corporation is concluding the fourth and final phase of the DARPA Navigation Grade Integrated Micro Gyro (NGIMG) program. Traditional MEMS gyros utilize springs as an inherent part of the sensing mechanism, leading to bias and scale factor sensitivity to acceleration and vibration. As a result, they have not met performance expectations in real world environments and to date have been limited to tactical grade applications. The Nuclear Magnetic Resonance Gyroscope (NMRG) utilizes the fixed precession rate of a nuclear spin in a constant magnetic field as an inertial reference for determining rotation. The nuclear spin precession rate sensitivity to acceleration and vibration is negligible for most applications. Therefore, the application of new micro and batch fabrication methods to NMRG technology holds great promise for navigation grade performance in a low cost and compact gyro. This poster will describe the history, operational principles, and design basics of the NMRG including an overview of the NSD designs developed and demonstrated in the DARPA gyro development program. General performance results from phases 3 and 4 will also be presented.

  9. Nuclear Magnetic Resonance Gyroscope

    NASA Astrophysics Data System (ADS)

    Larsen, Michael; Griffith, Robert; Bulatowicz, Michael

    2014-03-01

    The navigation grade micro Nuclear Magnetic Resonance Gyroscope (micro-NMRG) being developed by the Northrop Grumman Corporation (NGC) has concluded the fourth and final phase of the DARPA Navigation Grade Integrated Micro Gyro (NGIMG) program. Traditional MEMS gyros utilize springs as an inherent part of the sensing mechanism, leading to bias and scale factor sensitivity to acceleration and vibration. As a result, they have not met performance expectations in real world environments and to date have been limited to tactical grade applications. The Nuclear Magnetic Resonance Gyroscope (NMRG) utilizes the fixed precession rate of a nuclear spin in a constant magnetic field as an inertial reference for determining rotation. The nuclear spin precession rate sensitivity to acceleration and vibration is negligible for most applications. Therefore, the application of new micro and batch fabrication methods to NMRG technology holds great promise for navigation grade performance in a low cost and compact gyro. This presentation will describe the operational principles, design basics, and demonstrated performance of the NMRG including an overview of the NGC designs developed and demonstrated in the DARPA gyro development program.

  10. Nuclear fuel microsphere gamma analyzer

    DOEpatents

    Valentine, Kenneth H.; Long, Jr., Ernest L.; Willey, Melvin G.

    1977-01-01

    A gamma analyzer system is provided for the analysis of nuclear fuel microspheres and other radioactive particles. The system consists of an analysis turntable with means for loading, in sequence, a plurality of stations within the turntable; a gamma ray detector for determining the spectrum of a sample in one section; means for analyzing the spectrum; and a receiver turntable to collect the analyzed material in stations according to the spectrum analysis. Accordingly, particles may be sorted according to their quality; e.g., fuel particles with fractured coatings may be separated from those that are not fractured, or according to other properties.

  11. nuclear magnetic resonance gyroscope

    SciTech Connect

    Karwacki, F. A.; Griffin, J.

    1985-04-02

    A nuclear magnetic resonance gyroscope which derives angular rotation thereof from the phases of precessing nuclear moments utilizes a single-resonance cell situated in the center of a uniform DC magnetic field. The field is generated by current flow through a circular array of coils between parallel plates. It also utilizes a pump and read-out beam and associated electronics for signal processing and control. Encapsulated in the cell for sensing rotation are odd isotopes of Mercury Hg/sup 199/ and Hg/sup 201/. Unpolarized intensity modulated light from a pump lamp is directed by lenses to a linear polarizer, quarter wave plate combination producing circularly polarized light. The circularly polarized light is reflected by a mirror to the cell transverse to the field for optical pumping of the isotopes. Unpolarized light from a readout lamp is directed by lenses to another linear polarizer. The linearly polarized light is reflected by another mirror to the cell transverse to the field and orthogonal to the pump lamp light. The linear light after transversing the cell strikes an analyzer where it is converted to an intensity-modulated light. The modulated light is detected by a photodiode processed and utilized as feedback to control the field and pump lamp excitation and readout of angular displacement.

  12. Preliminary Study of the Efficacy of Using Nuclear Resonance Fluorescence with Quasi-Monoenergetic Gamma-Ray Sources for Nuclear Safeguards Assay

    SciTech Connect

    Johnson, M S; McNabb, D P; Hall, J M; Gonzalez, J J

    2011-02-17

    We have studied the efficacy of using nuclear resonance fluorescence (NRF)-based techniques to assay spent nuclear fuel for Pu content using quasi-monoenergetic sources. We have developed two techniques to precisely determine the Pu content in a fuel rod/pin. One of our approaches is virtually free of systematic uncertainties. Using analytical models, we have determined the amount of time required to measure the Pu content in spent nuclear fuel rods and spent fuel assemblies to within 1% precision. We note that Pu content can be determined in a fuel assembly about as fast as in a single fuel pin. The performance of NRF-based assay techniques with improved photon sources, which are currently under development, will also estimated. For follow-on research we propose to: (1) Construct research prototype detection systems for both of the NRF-based assay systems proposed in this paper and measure their calibration curves; (2) Determine the systematic errors associated with both assay methods, explore ways to reduce the errors and fold the results into future performance calculations; (3) Develop an algorithm to assay a fuel assembly; (4) Perform validation measurements using a single pin and scaled assemblies; (5) Research and develop current-mode detection and/or threshold detection techniques to improve assay times; (6) Characterize the flux of newly constructed sources and fold the results into the calculations presented here to determine the feasibility of a variety of proposed sources; and (7) Collaborate with others in the safeguards community to build a prototype system and perform an NRF-based assay demonstration on spent fuel.

  13. Nuclear gamma rays from energetic particle interactions

    NASA Technical Reports Server (NTRS)

    Ramaty, R.; Kozlovsky, B.; Lingenfelter, R. E.

    1978-01-01

    Gamma ray line emission from nuclear deexcitation following energetic particle reactions is evaluated. The compiled nuclear data and the calculated gamma ray spectra and intensities can be used for the study of astrophysical sites which contain large fluxes of energetic protons and nuclei. A detailed evaluation of gamma ray line production in the interstellar medium is made.

  14. Investigation of gamma radiation effect on the anion exchange resin Amberlite IRA-400 in hydroxide form by Fourier transformed infrared and 13C nuclear magnetic resonance spectroscopies.

    PubMed

    Traboulsi, A; Dupuy, N; Rebufa, C; Sergent, M; Labed, V

    2012-03-02

    Radiation-induced decomposition of the anion exchange resin Amberlite IRA-400 in hydroxide form by gamma radiolysis has been studied under different irradiation doses and irradiation atmospheres. In this work, we focused on the degradation of the solid part of the resin by Fourier transformed infrared (FTIR) and (13)C nuclear magnetic resonance (NMR) spectroscopies associated with chemometric treatments. FTIR and (13)C NMR techniques showed that only -CH(2)N(+)(CH(3))(3) groups were detached from the resin whereas the polystyrene divinylbenzene backbone remains intact. The quaternary ammonium groups were replaced by amine or carbonyl groups according to the irradiation atmosphere (with or without water or oxygen). Principal components analysis (PCA) was used to classify the degraded resins according to their irradiation conditions by separating the effect of the dose or the environment. The PCA loadings have shown spectral regions which discriminate the irradiated resins whereas SIMPLe-to-use Interactive Self-modeling Mixture Analysis (SIMPLISMA) allows to identify families of component characterizing the chemical structure of resins and estimate their relative contributions according to the irradiation atmospheres.

  15. Nuclear Magnetic Resonance Gyroscope

    NASA Astrophysics Data System (ADS)

    Larsen, Michael; Bulatowicz, Michael; Clark, Philip; Griffith, Robert; Mirijanian, James; Pavell, James

    2015-05-01

    The Nuclear Magnetic Resonance Gyroscope (NMRG) is being developed by the Northrop Grumman Corporation (NGC). Cold and hot atom interferometer based gyroscopes have suffered from Size, Weight, and Power (SWaP) challenges and limits in bandwidth, scale factor stability, dead time, high rotation rate, vibration, and acceleration. NMRG utilizes the fixed precession rate of a nuclear spin in a constant magnetic field as a reference for determining rotation, providing continuous measurement, high bandwidth, stable scale factor, high rotation rate measurement, and low sensitivity to vibration and acceleration in a low SWaP package. The sensitivity to vibration has been partially tested and demonstrates no measured sensitivity within error bars. Real time closed loop implementation of the sensor significantly decreases environmental and systematic sensitivities and supports a compact and low power digital signal processing and control system. Therefore, the NMRG technology holds great promise for navigation grade performance in a low cost SWaP package. The poster will describe the history, operation, and design of the NMRG. General performance results will also be presented along with recent vibration test results.

  16. Nuclear-resonant electron scattering

    NASA Astrophysics Data System (ADS)

    Pálffy, Adriana; Harman, Zoltán

    2008-04-01

    We investigate nuclear-resonant electron scattering as occurring in the two-step process of nuclear excitation by electron capture (NEEC) followed by internal conversion. The nuclear excitation and decay are treated by a phenomenological collective model in which nuclear states and transition probabilities are described by experimental parameters. We present capture rates and resonant strengths for a number of heavy-ion collision systems considering various scenarios for the resonant electron-scattering process. The results show that for certain cases resonant electron scattering can have significantly larger resonance strengths than NEEC followed by the radiative decay of the nucleus. We discuss the impact of our findings on the possible experimental observation of NEEC.

  17. Nuclear Magnetic Resonance

    NASA Astrophysics Data System (ADS)

    Reuhs, Bradley L.; Simsek, Senay

    Nuclear magnetic resonance (NMR) spectroscopy is a powerful analytical technique with a wide variety of applications. It may be used for complex structural studies, for protocol or process development, or as a simple quality assay for which structural information is important. It is nondestructive, and high-quality data may be obtained from milligram, even microgram, quantities of sample. Whereas other spectroscopy techniques may be used to determine the nature of the functional groups present in a sample, only NMR spectroscopy can provide the data necessary to determine the complete structure of a molecule. The applicability of NMR to food analysis has increased over the last three decades. In addition to improved instrumentation and much lower costs, very complex and specialized NMR techniques can now be routinely performed by a student or technician. These experiments can be set up with the click of a button/icon, as all the basic parameters are embedded into default experiment files listed in the data/work station software, and the results are obtained in a short time.

  18. Introduction to nuclear magnetic resonance.

    PubMed

    Mlynárik, Vladimír

    2016-05-19

    Nuclear magnetic resonance spectroscopy is a useful tool for studying normal and pathological biochemical processes in tissues. In this review, the principles of nuclear magnetic resonance and methods of obtaining nuclear magnetic resonance spectra are briefly outlined. The origin of the most important spectroscopic parameters-chemical shifts, coupling constants, longitudinal and transverse relaxation times, and spectroscopic line intensities-is explained, and the role of these parameters in interpretation of spectra is addressed. Basic methodological concepts of localized spectroscopy and spectroscopic imaging for the study of tissue metabolism in vivo are also described.

  19. Nondestructive identification of isotopes using nuclear resonance fluorescence

    SciTech Connect

    Shizuma, Toshiyuki; Hayakawa, Takehito; Hajima, Ryoichi; Kikuzawa, Nobuhiro; Ohgaki, Hideaki; Toyokawa, Hiroyuki

    2012-01-15

    Nondestructive identification of heavy isotopes concealed in a thick iron box has been demonstrated by using nuclear resonance fluorescence. A quasi-monochromatic photon beam produced by the collision of laser quanta with high energy electrons was used for resonant excitation of nuclear levels in {sup 206}Pb and {sup 208}Pb. By measuring the resonant {gamma} rays emitted from {sup 206}Pb and {sup 208}Pb, each of these isotopes were clearly identified. The ratio of the effective thickness, i.e., concentration distribution, of these isotopes was deduced from the relative intensities of the measured nuclear resonance fluorescence strengths.

  20. Nuclear quadrupole resonance spectra database

    NASA Astrophysics Data System (ADS)

    Chihara, H.

    A computer-readable file of numerical data of nuclear quadrupole resonance frequency is being built which also serves as a bibliographic file. The data are compiled by reviewing original papers, reprints, and published data books and retrieving such data elements as substance names, nuclear mass number, temperature of measurements, resonance frequencies, nuclear quadrupole coupling constants, asymmetry parameters, and keywords. The database contains, if available, CAS registry number, molecular formulas and systematic names, and other synonyms of chemical substances. About 800 records have been loaded for online, TSS search through the Computer Center of Osaka University.

  1. Nuclear magnetic resonance study of interaction of ligands with Streptococcus faecium dihydrofolate reductase labeled with (. gamma. -/sup 13/C)tryptophan

    SciTech Connect

    London, R.E.; Groff, J.P.; Cocco, L.; Blakley, R.L.

    1982-01-01

    Dihydrofolate reductase from Streptococcus faecium has been labeled with (..gamma..-/sup 13/C)tryptophan. We have determined changes occurring in the chemical shifts and line widths of the four resonances of the /sup 13/C NMR spectrum of the labeled enzyme, due to its interaction with various ligands. These include the coenzyme, NPDPH and related nucleotides, folate and its polyglutamate derivatives, and many inhibitors including methotrexate and trimethoprim. In addition, paramagnetic relaxation effects produced by a bound spin-labeled analogue of 2'-phosphoadenosine-5'-diphosphoribose on the tryptophan C/sup ..gamma../ carbons have been measured. Distances calculated from the relaxation data have been compared with corresponding distances in the crystallographic model of the NADPH-methotrexate ternary complex of Lactobacillus casei reductase. The paramagnetic relaxation data indicate that the two downfield resonances (1 and 2) correspond to tryptophans (W/sub A/ and W/sub B/) that are more remote from the catalytic site, and from the crystallographic model these are seen to be Trp-115 and Trp-160. The upfield resonances (3 and 4) that show broadening due to chemical exchange correspond to closer residues (W/sub C/ and W/sub D/), and these are identified with Trp-6 and Trp-22. However, the relaxation data do not permit specific assignments within the nearer and farther pairs. Although resonance 3, which is split due to chemical exchange, was formerly assigned to Trp-6, data obtained for the enzyme in the presence of various ligands are better interpreted if resonance 3 is assigned to Trp-22, which is located on a loop that joins elements of secondary structure and forms one side of the ligand-binding cavity.

  2. Nuclear magnetic resonance blood flowmeter

    SciTech Connect

    Battocletti, J.H.; Halbach, R.E.; Antonich, F.J.; Sances, A. Jr.; Knox, T.A.

    1986-09-23

    An improved nuclear magnetic resonance blood flowmeter is described for non-invasively measuring blood flow in a human limb comprising; polarizing magnet means for generating a substantially uniform magnetic field; a limb receiving lumen for supporting a human limb within the field generated by the polarizing magnet means so that blood molecules within the limb are magnetically polarized thereby; transmitter means located adjacent the lumen for inducing a nuclear magnetic resonance response in the blood molecules of the human limb disposed within the lumen; scanning means including: first means for generating a first pair of opposing magnetic fields within the lumen for cancelling the nuclear magnetic resonance response induced by the transmitter means everywhere except within a first null plane along which the first opposing magnetic fields cancel each other; second means for generating a second pair of opposing magnetic fields; and control means coupled to the first and second means for generating the first and second pair of opposing magnetic fields.

  3. Compact Gamma-Beam Source for Nuclear Security Technologies

    NASA Astrophysics Data System (ADS)

    Gladkikh, P.; Urakawa, J.

    2015-10-01

    A compact gamma-beam source dedicated to the development of the nuclear security technologies by use of the nuclear resonance fluorescence is described. Besides, such source is a very promising tool for novel technologies of the express cargoes inspection to prevent nuclear terrorism. Gamma-beam with the quanta energies from 0.3MeV to 7.2MeV is generated in the Compton scattering of the "green" laser photons on the electron beam with energies from 90MeV to 430MeV. The characteristic property of the proposed gammabeam source is a narrow spectrum (less than 1%) at high average gamma-yield (of 1013γ/s) due to special operation mode.

  4. Gamma-ray astronomy: Nuclear transition region

    NASA Technical Reports Server (NTRS)

    Chupp, E. L.

    1976-01-01

    This monograph reviews the major theoretical and experimental efforts made during the past 12 years in gamma-ray astronomy over the energy range from 10 keV to about 100 MeV, where nuclear-transition lines are expected. Early attempts to detect celestial gamma rays are recounted, mechanisms of gamma-ray line and continuum production are examined, and formulas giving the various possible differential gamma-ray spectral shapes are provided. Predicted fluxes are discussed for solar gamma rays as well as for gamma emission from supernova remnants, supernovae, neutron stars, flare stars, the galactic core and disk, black holes, and diffuse sources. Gamma-ray interactions with matter are analyzed, particularly the photoelectric effect, Compton scattering from free electrons, and pair production in nuclear fields. Significant results are summarized for observations of gamma rays from the sun as well as from point and extended sources within and beyond the Galaxy, including diffuse fluxes and transient gamma-ray bursts. Factors pertaining to the design of gamma-ray astronomy experiments are considered, especially detector background limitations, gamma-ray production within instruments, and present-day detection methods.

  5. Gamma-ray astronomy: Nuclear transition region

    NASA Technical Reports Server (NTRS)

    Chupp, E. L.

    1976-01-01

    This monograph reviews the major theoretical and experimental efforts made during the past 12 years in gamma-ray astronomy over the energy range from 10 keV to about 100 MeV, where nuclear-transition lines are expected. Early attempts to detect celestial gamma rays are recounted, mechanisms of gamma-ray line and continuum production are examined, and formulas giving the various possible differential gamma-ray spectral shapes are provided. Predicted fluxes are discussed for solar gamma rays as well as for gamma emission from supernova remnants, supernovae, neutron stars, flare stars, the galactic core and disk, black holes, and diffuse sources. Gamma-ray interactions with matter are analyzed, particularly the photoelectric effect, Compton scattering from free electrons, and pair production in nuclear fields. Significant results are summarized for observations of gamma rays from the sun as well as from point and extended sources within and beyond the Galaxy, including diffuse fluxes and transient gamma-ray bursts. Factors pertaining to the design of gamma-ray astronomy experiments are considered, especially detector background limitations, gamma-ray production within instruments, and present-day detection methods.

  6. Nuclear Forensics using Gamma-ray Spectroscopy

    NASA Astrophysics Data System (ADS)

    Norman, E. B.

    2016-09-01

    Much of George Dracoulis's research career was devoted to utilising gamma-ray spectroscopy in fundamental studies in nuclear physics. This same technology is useful in a wide range of applications in the area of nuclear forensics. Over the last several years, our research group has made use of both high- and low-resolution gamma-ray spectrometers to: identify the first sample of plutonium large enough to be weighed; determine the yield of the Trinity nuclear explosion; measure fission fragment yields as a function of target nucleus and neutron energy; and observe fallout in the U. S. from the Fukushima nuclear reactor accident.

  7. Assessment of Nuclear Resonance Fluorescence for Spent Nuclear Fuel Assay

    SciTech Connect

    Quiter, Brian; Ludewigt, Bernhard; Ambers, Scott

    2011-06-30

    In nuclear resonance fluorescence (NRF) measurements, resonances are excited by an external photon beam leading to the emission of gamma rays with specific energies that are characteristic of the emitting isotope. NRF promises the unique capability of directly quantifying a specific isotope without the need for unfolding the combined responses of several fissile isotopes as is required in other measurement techniques. We have analyzed the potential of NRF as a non-destructive analysis technique for quantitative measurements of Pu isotopes in spent nuclear fuel (SNF). Given the low concentrations of 239Pu in SNF and its small integrated NRF cross sections, the main challenge in achieving precise and accurate measurements lies in accruing sufficient counting statistics in a reasonable measurement time. Using analytical modeling, and simulations with the radiation transport code MCNPX that has been experimentally tested recently, the backscatter and transmission methods were quantitatively studied for differing photon sources and radiation detector types. Resonant photon count rates and measurement times were estimated for a range of photon source and detection parameters, which were used to determine photon source and gamma-ray detector requirements. The results indicate that systems based on a bremsstrahlung source and present detector technology are not practical for high-precision measurements of 239Pu in SNF. Measurements that achieve the desired uncertainties within hour-long measurements will either require stronger resonances, which may be expressed by other Pu isotopes, or require quasi-monoenergetic photon sources with intensities that are approximately two orders of magnitude higher than those currently being designed or proposed.This work is part of a larger effort sponsored by the Next Generation Safeguards Initiative to develop an integrated instrument, comprised of individual NDA techniques with complementary features, that is fully capable of

  8. Shiftless nuclear magnetic resonance spectroscopy.

    PubMed

    Wu, Chin H; Opella, Stanley J

    2008-02-07

    The acquisition and analysis of high resolution one- and two-dimensional solid-state nuclear magnetic resonance (NMR) spectra without chemical shift frequencies are described. Many variations of shiftless NMR spectroscopy are feasible. A two-dimensional experiment that correlates the dipole-dipole and dipole-dipole couplings in the model peptide , (15)N labeled N-acetyl-leucine is demonstrated. In addition to the resolution of resonances from individual sites in a single crystal sample, the bond lengths and angles are characterized by the two-dimensional powder pattern obtained from a polycrystalline sample.

  9. Nuclear photofission studies with monochromatic {gamma} ray beams

    SciTech Connect

    Csige, L.; Gulyas, J.; Habs, D.; Krasznahorkay, A.; Thirolf, P. G.; Tornyi, T. G.

    2012-07-09

    Two new research facilities will be ready for operation very soon (MEGa-Ray at Liver-more National Laboratory) or start construction (ELI-Nuclear Physics in Bucharest), both providing highly brilliant {gamma} beams with so far unprecedented properties via Compton backscattering of laser photons from a high-quality, relativistic electron beam. With these intense, monochromatic {gamma} beams, a new era of photonuclear physics will be enabled. A new research campaign is proposed to exploit the unprecedented properties of these highly-brilliant, novel {gamma} beams on highly-selective studies of extremely deformed nuclei in the multiple-humped potential energy landscape of the actinides via photofission. With the unique {gamma} beam bandwidth of {Delta}E/E = 10{sup -3}, we can aim at resolving individual resonances which could never be achieved so far due to the limited {gamma} bandwidth of bremsstrahlung beams. Exploratory, non-bremsstrahlung photofission experiments are going to be performed very soon at the HI{gamma}S facility (Duke University, USA) to investigate the fine structure of the sub-barrier transmission resonances of the actinides.

  10. Nuclear isomer suitable for gamma ray laser

    NASA Technical Reports Server (NTRS)

    Jha, S.

    1979-01-01

    The operation of gamma ray lasers (gasers) are studied. It is assumed that the nuclear isomers mentioned in previously published papers have inherent limitations. It is further assumed that the judicious use of Bormann effect or the application of the total external reflection of low energy gamma radiation at grazing angle of incidence may permit the use of a gaser crystal sufficiently long to achieve observable stimulated emission. It is suggested that a long lived 0(+) isomer decaying by low energy gamma ray emission to a short lived 2(+) excited nuclear state would be an attractive gaser candidate. It is also suggested that the nuclear isomer be incorporated in a matrix of refractory material having an electrostatic field gradient whose principal axis lies along the length of the medium. This results in the preferential transmission of electric quadrupole radiation along the length of the medium.

  11. Experimental Overview of Compound Nuclear Resonance Reactions

    SciTech Connect

    Mitchell, G. E.

    2008-04-17

    The major issues of compound nuclear resonance reactions are briefly summarized: A--How to measure the resonances, B--How to categorize the resonances (spin, parity, resonance energy and strength), C--How to describe the distribution of resonance strengths and spacings, D--How to assess data quality.

  12. Nuclear physics with advanced brilliant gamma beams at ELI-NP

    NASA Astrophysics Data System (ADS)

    Ur, Călin A.; Filipescu, Dan; Gheorghe, Ioana; Iancu, Violeta; Suliman, Gabriel; Teşileanu, Ovidiu

    2016-01-01

    The Extreme Light Infrastructure - Nuclear Physics facility is dedicated to nuclear physics studies with the use of extreme electromagnetic radiation. One of the main research system to be installed and operated in the facility is an outstanding high brilliance gamma beam system. The Gamma Beam System of ELI-NP will produce intense, quasi-monochromatic gamma beams via inverse Compton scattering of short laser pulses on relativistic electron beam pulses. The gamma beams available at ELI-NP will allow for the performance of photo-nuclear reactions aiming to reveal the intimate structure of the atomic nucleus. Nuclear Resonance Fluorescence, photo-fission, photo-disintegration reactions above the particle threshold will be used to study the dipole response of nuclei, the structure of the Pygmy resonances, nuclear processes relevant for astrophysics, production and study of exotic neutron-rich nuclei.

  13. Structure of the glycopeptides of a human gamma 1-immunoglobulin G (Tem) myeloma protein as determined by 360-megahertz nuclear magnetic resonance spectroscopy.

    PubMed

    Grey, A A; Narasimhan, S; Brisson, J R; Schachter, H; Carver, J P

    1982-12-01

    High field magnetic resonance spectroscopy has been utilized to deduce the primary structure of the glycopeptides from a human myeloma gamma 1-immunoglobulin G (Tem). The major structures found belong to the biantennary complex class of glycopeptides, with a minor (5%) fraction belonging to the bisected biantennary complex class. In the biantennary class, three structures were present with different residues at the termini of the alpha Man(1-6) and alpha Man(1-3) arms: (i) with beta Gal(1-4) and alpha NeuNAc(2-6), respectively (33%); (ii) with beta Gal(1-4) and beta Gal(1-4), respectively (45%); and (iii) beta Gal(1-4) and beta GlcNAc(1-2), respectively (17%). In the bisected biantennary class only the latter termini were found for the two arms. These results suggest that the galactosyl transferase in these cells has a preference for the beta GlcNAc(1-2) of the alpha Man(1-6) arm and that the sialyltransferase has a preference for the beta Gal(1-4) of the alpha Man(1-3) arm.

  14. Evanescent Waves Nuclear Magnetic Resonance

    PubMed Central

    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

  15. Nuclear Resonance Fluorescence Measurements of High Explosives

    SciTech Connect

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

    2007-12-31

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

  16. Oxygen depth profiling by nuclear resonant scattering

    SciTech Connect

    Gibson, G. T.; Sheu, W. J.; Glass, G. A.; Wang, Y. Q.

    1999-06-10

    Nuclear resonance scattering (NRS) {sup 16}O({alpha},{alpha}){sup 16}O at 3.045 MeV ({gamma}=10 keV) has been used for oxygen depth profiling in various thin oxide films. There are two ways by which the oxygen concentration versus depth profile can be obtained from the experimental data: energy spectrum simulation or yield distribution analysis. Energy spectrum simulation is done using the standard RBS software/Rutherford Universal Manipulation Program (RUMP) where only one spectrum is usually needed from the measurement. Yield distribution analysis is accomplished by using a custom developed software/Resonance Analysis Program (RAP) and involves a series of spectra obtained by stepping up the beam energy above the resonance energy. This article aims at comparing the fundamentals of both methods and also discussing their advantages and disadvantages in terms of the data acquisition and the post data analysis. A thermally grown thick SiO{sub 2} film and a thin titanium oxide film grown by corona point discharge were examined.

  17. Oxygen depth profiling by nuclear resonant scattering

    SciTech Connect

    Gibson, G.T.; Sheu, W.J.; Glass, G.A. Wang, Y.Q.

    1999-06-01

    Nuclear resonance scattering (NRS) {sup 16}O({alpha},{alpha}){sup 16}O at 3.045 MeV ({Gamma}=10&hthinsp;keV) has been used for oxygen depth profiling in various thin oxide films. There are two ways by which the oxygen concentration versus depth profile can be obtained from the experimental data: energy spectrum simulation or yield distribution analysis. Energy spectrum simulation is done using the standard RBS software/Rutherford Universal Manipulation Program (RUMP) where only one spectrum is usually needed from the measurement. Yield distribution analysis is accomplished by using a custom developed software/Resonance Analysis Program (RAP) and involves a series of spectra obtained by stepping up the beam energy above the resonance energy. This article aims at comparing the fundamentals of both methods and also discussing their advantages and disadvantages in terms of the data acquisition and the post data analysis. A thermally grown thick SiO{sub 2} film and a thin titanium oxide film grown by corona point discharge were examined. {copyright} {ital 1999 American Institute of Physics.}

  18. Nuclear magnetic resonance studies of lens transparency

    SciTech Connect

    Beaulieu, C.F.

    1989-01-01

    Transparency of normal lens cytoplasm and loss of transparency in cataract were studied by nuclear magnetic resonance (NMR) methods. Phosphorus ({sup 31}P) NMR spectroscopy was used to measure the {sup 31}P constituents and pH of calf lens cortical and nuclear homogenates and intact lenses as a function of time after lens enucleation and in opacification produced by calcium. Transparency was measured with laser spectroscopy. Despite complete loss of adenosine triphosphate (ATP) within 18 hrs of enucleation, the homogenates and lenses remained 100% transparent. Additions of calcium to ATP-depleted cortical homogenates produced opacification as well as concentration-dependent changes in inorganic phosphate, sugar phosphates, glycerol phosphorylcholine and pH. {sup 1}H relaxation measurements of lens water at 200 MHz proton Larmor frequency studied temperature-dependent phase separation of lens nuclear homogenates. Preliminary measurements of T{sub 1} and T{sub 2} with non-equilibrium temperature changes showed a change in the slope of the temperature dependence of T{sub 1} and T{sub 2} at the phase separation temperature. Subsequent studies with equilibrium temperature changes showed no effect of phase separation on T{sub 1} or T{sub 2}, consistent with the phase separation being a low-energy process. {sup 1}H nuclear magnetic relaxation dispersion (NMRD) studies (measurements of the magnetic field dependence of the water proton 1/T{sub 1} relaxation rates) were performed on (1) calf lens nuclear and cortical homogenates (2) chicken lens homogenates, (3) native and heat-denatured egg white and (4) pure proteins including bovine {gamma}-II crystallin bovine serum albumin (BSA) and myoglobin. The NMRD profiles of all samples exhibited decreases in 1/T{sub 1} with increasing magnetic field.

  19. Microcoil nuclear magnetic resonance spectroscopy.

    PubMed

    Webb, A G

    2005-08-10

    In comparison with most analytical chemistry techniques, nuclear magnetic resonance has an intrinsically low sensitivity, and many potential applications are therefore precluded by the limited available quantity of certain types of sample. In recent years, there has been a trend, both commercial and academic, towards miniaturization of the receiver coil in order to increase the mass sensitivity of NMR measurements. These small coils have also proved very useful in coupling NMR detection with commonly used microseparation techniques. A further development enabled by small detectors is parallel data acquisition from many samples simultaneously, made possible by incorporating multiple receiver coils into a single NMR probehead. This review article summarizes recent developments and applications of "microcoil" NMR spectroscopy.

  20. Introduction to Nuclear Magnetic Resonance

    NASA Technical Reports Server (NTRS)

    Manatt, Stanley L.

    1985-01-01

    The purpose of this paper is to try to give a short overview of what the status is on nuclear magnetic resonance (NMR). It's a subject where one really has to spend some time to look at the physics in detail to develop a proper working understanding. I feel it's not appropriate to present to you density matrices, Hamiltonians of all sorts, and differential equations representing the motion of spins. I'm really going to present some history and status, and show a few very simple concepts involved in NMR. It is a form of radio frequency spectroscopy and there are a great number of nuclei that can be studied very usefully with the technique. NMR requires a magnet, a r.f. transmitter/receiver system, and a data acquisition system.

  1. Gamma radiation induced changes in nuclear waste glass containing Eu

    NASA Astrophysics Data System (ADS)

    Mohapatra, M.; Kadam, R. M.; Mishra, R. K.; Kaushik, C. P.; Tomar, B. S.; Godbole, S. V.

    2011-10-01

    Gamma radiation induced changes were investigated in sodium-barium borosilicate glasses containing Eu. The glass composition was similar to that of nuclear waste glasses used for vitrifying Trombay research reactor nuclear waste at Bhabha Atomic Research Centre, India. Photoluminescence (PL) and electron paramagnetic resonance (EPR) techniques were used to study the speciation of the rare earth (RE) ion in the matrix before and after gamma irradiation. Judd-Ofelt ( J- O) analyses of the emission spectra were done before and after irradiation. The spin counting technique was employed to quantify the number of defect centres formed in the glass at the highest gamma dose studied. PL data suggested the stabilisation of the trivalent RE ion in the borosilicate glass matrix both before and after irradiation. It was also observed that, the RE ion distributes itself in two different environments in the irradiated glass. From the EPR data it was observed that, boron oxygen hole centre based radicals are the predominant defect centres produced in the glass after irradiation along with small amount of E’ centres. From the spin counting studies the concentration of defect centres in the glass was calculated to be 350 ppm at 900 kGy. This indicated the fact that bulk of the glass remained unaffected after gamma irradiation up to 900 kGy.

  2. Prospects for Nuclear-gamma-ray Astronomy

    NASA Technical Reports Server (NTRS)

    Clayton, D. D.

    1973-01-01

    An analysis was made of prospects for gamma rays coming from two sources outside the solar system: (1) radioactive decay of fresh nuclear products to explosive nucleosynthesis, and (2) scattering of low energy cosmic rays. The former should be detectable and will provide a factual base for many suppositions about the site and history of nucleosynthesis. The latter may be detectable and, if so, will probably provide factual information about high-flux regions of cosmic radiation.

  3. Prospects for Nuclear-gamma-ray Astronomy

    NASA Technical Reports Server (NTRS)

    Clayton, D. D.

    1973-01-01

    An analysis was made of prospects for gamma rays coming from two sources outside the solar system: (1) radioactive decay of fresh nuclear products to explosive nucleosynthesis, and (2) scattering of low energy cosmic rays. The former should be detectable and will provide a factual base for many suppositions about the site and history of nucleosynthesis. The latter may be detectable and, if so, will probably provide factual information about high-flux regions of cosmic radiation.

  4. Wide-range nuclear magnetic resonance detector

    NASA Technical Reports Server (NTRS)

    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. Nature of the pygmy dipole resonance in 140Ce studied in (alpha, alpha' gamma) experiments.

    PubMed

    Savran, D; Babilon, M; van den Berg, A M; Harakeh, M N; Hasper, J; Matic, A; Wörtche, H J; Zilges, A

    2006-10-27

    A concentration of electric-dipole excitations below the particle threshold, which is frequently denoted as the pygmy dipole resonance, has been studied in the semimagic nucleus 140Ce in (alpha, alpha' gamma) experiments at E alpha = 136 MeV. The technique of alpha-gamma coincidence experiments allows the separation of E1 excitations from states of other multipolarities in the same energy region and provides an excellent energy resolution to allow a detailed analysis for each state. The experimental results show that the PDR splits into two parts with different nuclear structure: one part which is excited in (alpha, alpha' gamma) as well as (gamma, gamma') experiments and one part which is excited only in (gamma, gamma').

  6. Nuclear Resonance Fluorescence for Safeguards Applications

    SciTech Connect

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

    2011-02-04

    In nuclear resonance fluorescence (NRF) measurements, resonances are excited by an external photon beam leading to the emission of {gamma} rays with specific energies that are characteristic of the emitting isotope. The promise of NRF as a non-destructive analysis technique (NDA) in safeguards applications lies in its potential to directly quantify a specific isotope in an assay target without the need for unfolding the combined responses of several fissile isotopes as often required by other NDA methods. The use of NRF for detection of sensitive nuclear materials and other contraband has been researched in the past. In the safeguards applications considered here one has to go beyond mere detection and precisely quantify the isotopic content, a challenge that is discussed throughout this report. Basic NRF measurement methods, instrumentation, and the analytical calculation of NRF signal strengths are described in Section 2. Well understood modeling and simulation tools are needed for assessing the potential of NRF for safeguards and for designing measurement systems. All our simulations were performed with the radiation transport code MCNPX, a code that is widely used in the safeguards community. Our initial studies showed that MCNPX grossly underestimated the elastically scattered background at backwards angles due to an incorrect treatment of Rayleigh scattering. While new, corrected calculations based on ENDF form factors showed much better agreement with experimental data for the elastic scattering of photons on an uranium target, the elastic backscatter is still not rigorously treated. Photonuclear scattering processes (nuclear Thomson, Delbruck and Giant Dipole Resonance scattering), which are expected to play an important role at higher energies, are not yet included. These missing elastic scattering contributions were studied and their importance evaluated evaluated against data found in the literature as discussed in Section 3. A transmission experiment

  7. Nuclear magnetic resonance spectroscopic study of beta-lactoglobulin interactions with two flavor compounds, gamma-decalactone and beta-ionone.

    PubMed

    Lübke, Markus; Guichard, Elisabeth; Tromelin, Anne; Le Quéré, Jean Luc

    2002-11-20

    Interactions between a well-characterized protein, beta-lactoglobulin, and two flavor compounds, beta-ionone and gamma-decalactone, were studied by 2D NMR spectroscopy. NMR spectra were recorded in aqueous solution (pH 2.0, 12 mM NaCl, 10% D(2)O) under conditions such that beta-lactoglobulin is present in a monomeric state. TOCSY and NOESY spectra were recorded on the protein and the complexes between protein and ligands. The spectra of the NH-CH(alpha) region showed the cross-signals due to the coupling between N- and C-bonded protons in the polypeptide backbone. The observed chemical shift variations in the presence of ligands can be assigned to changes in the protein conformation. It appears that the side chains of several amino acids are affected by binding of gamma-decalactone point into the central cavity (Leu46, Ile56, Met107, and Gln120), whereas binding of beta-ionone affects amino acids located in a groove near the outer surface of the protein (Leu104, Tyr120, and Asp129), as illustrated by molecular visualization. This NMR study provides precise information of the location of binding and confirms the existence of two different binding sites for aroma compounds on beta-lactoglobulin, which was suggested in previous competition studies by fluorometry or affinity chromatography and by structural information obtained from infrared spectroscopy.

  8. An improved nuclear magnetic resonance spectrometer

    NASA Technical Reports Server (NTRS)

    Elleman, D. D.; Manatt, S. L.

    1967-01-01

    Cylindrical sample container provides a high degree of nuclear stabilization to a nuclear magnetic resonance /nmr/ spectrometer. It is placed coaxially about the nmr insert and contains reference sample that gives a signal suitable for locking the field and frequency of an nmr spectrometer with a simple audio modulation system.

  9. Nuclear Resonance Fluorescence of U-235

    SciTech Connect

    Warren, Glen A.; Caggiano, Joseph A.; Hensley, Walter K.; Lepel, Elwood A.; Pratt, Sharon L.; Bertozzi, William; Korbly, Steve; Ledoux, Robert; Park, William H.

    2009-07-13

    Nuclear resonance fluorescence is a physical process that provides an isotopic-specific signature that could be used for the identification and characterization of materials. The technique involves the detection of prompt discrete-energy photons emitted from a sample which is exposed to photons in the MeV energy range. Potential applications of the technique range from detection of high explosives to characterization of special nuclear materials. One isotope of significant interest is 235U. Pacific Northwest National Laboratory and Passport Systems have collaborated to conduct measurements to search for a nuclear resonance fluorescence response of 235U below 3 MeV using a 200 g sample of highly enriched uranium. Nine 235U resonances between 1650 and 2010 keV were identified in the preliminary analysis. Analysis of the measurement data to determine the integrated cross sections of the resonances is in progress.

  10. Nuclear magnetic resonance contrast agents

    DOEpatents

    Smith, P.H.; Brainard, J.R.; Jarvinen, G.D.; Ryan, R.R.

    1997-12-30

    A family of contrast agents for use in magnetic resonance imaging and a method of enhancing the contrast of magnetic resonance images of an object by incorporating a contrast agent of this invention into the object prior to forming the images or during formation of the images. A contrast agent of this invention is a paramagnetic lanthanide hexaazamacrocyclic molecule, where a basic example has the formula LnC{sub 16}H{sub 14}N{sub 6}. Important applications of the invention are in medical diagnosis, treatment, and research, where images of portions of a human body are formed by means of magnetic resonance techniques. 10 figs.

  11. Nuclear magnetic resonance contrast agents

    DOEpatents

    Smith, Paul H.; Brainard, James R.; Jarvinen, Gordon D.; Ryan, Robert R.

    1997-01-01

    A family of contrast agents for use in magnetic resonance imaging and a method of enhancing the contrast of magnetic resonance images of an object by incorporating a contrast agent of this invention into the object prior to forming the images or during formation of the images. A contrast agent of this invention is a paramagnetic lanthanide hexaazamacrocyclic molecule, where a basic example has the formula LnC.sub.16 H.sub.14 N.sub.6. Important applications of the invention are in medical diagnosis, treatment, and research, where images of portions of a human body are formed by means of magnetic resonance techniques.

  12. Nuclear gamma rays from stellar flares

    NASA Technical Reports Server (NTRS)

    Colgate, S. A.

    1978-01-01

    Solar flare observations are consistent with the phenomenological description that a loop of magnetic flux is convected to the surface of the star and twisted. The resulting inductive current parallel to the field is dissipated at an enhanced rate throughout the field volume by current limiting instabilities. The steady state balance between joule heating and thermal conduction along the field lines of force to the denser, cooler surface establishes a temperature distribution. The expansion of heated and ionized surface layers leads to a pressure balance and hence predictable density and X-ray emission measure. The current limitation instabilities result observationally in the parallel current being transferred to run-away ions that reach a kinetic energy of some finite fraction of the inductive potential drop. The nuclear excitation gamma rays produced by such a run-away ion current are calculated for a white dwarf flare.

  13. Nonelastic nuclear reactions and accompanying gamma radiation

    NASA Technical Reports Server (NTRS)

    Snow, R.; Rosner, H. R.; George, M. C.; Hayes, J. D.

    1971-01-01

    Several aspects of nonelastic nuclear reactions which proceed through the formation of a compound nucleus are dealt with. The full statistical model and the partial statistical model are described and computer programs based on these models are presented along with operating instructions and input and output for sample problems. A theoretical development of the expression for the reaction cross section for the hybrid case which involves a combination of the continuum aspects of the full statistical model with the discrete level aspects of the partial statistical model is presented. Cross sections for level excitation and gamma production by neutron inelastic scattering from the nuclei Al-27, Fe-56, Si-28, and Pb-208 are calculated and compared with avaliable experimental data.

  14. Membrane Resonance Enables Stable and Robust Gamma Oscillations

    PubMed Central

    Moca, Vasile V.; Nikolić, Danko; Singer, Wolf; Mureşan, Raul C.

    2014-01-01

    Neuronal mechanisms underlying beta/gamma oscillations (20–80 Hz) are not completely understood. Here, we show that in vivo beta/gamma oscillations in the cat visual cortex sometimes exhibit remarkably stable frequency even when inputs fluctuate dramatically. Enhanced frequency stability is associated with stronger oscillations measured in individual units and larger power in the local field potential. Simulations of neuronal circuitry demonstrate that membrane properties of inhibitory interneurons strongly determine the characteristics of emergent oscillations. Exploration of networks containing either integrator or resonator inhibitory interneurons revealed that: (i) Resonance, as opposed to integration, promotes robust oscillations with large power and stable frequency via a mechanism called RING (Resonance INduced Gamma); resonance favors synchronization by reducing phase delays between interneurons and imposes bounds on oscillation cycle duration; (ii) Stability of frequency and robustness of the oscillation also depend on the relative timing of excitatory and inhibitory volleys within the oscillation cycle; (iii) RING can reproduce characteristics of both Pyramidal INterneuron Gamma (PING) and INterneuron Gamma (ING), transcending such classifications; (iv) In RING, robust gamma oscillations are promoted by slow but are impaired by fast inputs. Results suggest that interneuronal membrane resonance can be an important ingredient for generation of robust gamma oscillations having stable frequency. PMID:23042733

  15. Extra gamma-ray strength for {sup 116,117}Sn arising from pygmy dipole resonance

    SciTech Connect

    Kamata, M.; Utsunomiya, H.; Akimune, H.; Yamagata, T.; Itoh, O.; Iwamoto, C.; Kondo, T.; Toyokawa, H.; Lui, Y.-W.; Goriely, S.

    2010-06-01

    Photoneutron cross sections were measured for {sup 117}Sn and {sup 116}Sn near neutron thresholds with quasi-monochromatic laser Compton scattering gamma-rays. The measured cross sections for {sup 117}Sn and {sup 116}Sn are strongly enhanced from the threshold behavior expected for L = 1 neutron emissions after E1 photoexcitation. This suggests the presence of extra gamma-ray strength in the low-energy tail of the giant dipole resonance. The present cross sections were analyzed together with radiative neutron capture cross sections for {sup 116}Sn within the framework of the statistical model calculation. It is shown that the extra gamma-ray strength can be interpreted as pygmy E1 resonance which was previously reported in the nuclear resonance fluorescence experiment for {sup 116}Sn and {sup 124}Sn.

  16. Satellite observation of atmospheric nuclear gamma radiation.

    PubMed

    Letaw, J R; Share, G H; Kinzer, R L; Silberberg, R; Chupp, E L; Forrest, D J; Rieger, E

    1989-02-01

    We present a satellite observation of the spectrum of gamma radiation from the Earth's atmosphere in the energy interval from 300 keV to 8.5 MeV. The data were accumulated by the gamma ray spectrometer on the Solar Maximum Mission over 3 1/2 years, from 1980 to 1983. The excellent statistical accuracy of the data allows 20 atmospheric line features to be identified. The features are superimposed on a continuum background which is modeled using a power law with index -1.16. Many of these features contain a blend of more than one nuclear line. All of these lines (with the exception of the 511-keV annihilation line) are Doppler broadened. Line energies and intensities are consistent with production by secondary neutrons interacting with atmospheric 14N and 16O. Although we find no evidence for other production mechanisms, we cannot rule out significant contributions from direct excitation or spallation by primary cosmic ray protons. The relative intensities of the observed line features are in fair agreement with theoretical models; however, existing models are limited by the availability of neutron cross sections, especially at high energies. The intensity and spectrum of photons at energies below the 511-keV line, in excess of a power law continuum, can be explained by Compton scattering of the annihilation line photons in traversing an average of approximately 21 g cm-2 of atmosphere.

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

    SciTech Connect

    Tomimatsu, Toru Shirai, Shota; Hashimoto, Katsushi Sato, Ken; Hirayama, Yoshiro

    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.

  18. Nuclear Magnetic Resonance Technology for Medical Studies

    NASA Astrophysics Data System (ADS)

    Budinger, Thomas F.; Lauterbur, Paul C.

    1984-10-01

    Nuclear magnetic resonance proton imaging provides anatomical definition of normal and abnormal tissues with a contrast and detection sensitivity superior to those of x-ray computed tomography in the human head and pelvis and parts of the cardiovascular and musculoskeletal systems. Recent improvements in technology should lead to advances in diagnostic imaging of the breast and regions of the abdomen. Selected-region nuclear magnetic resonance spectroscopy of protons, carbon-13, and phosphorus-31 has developed into a basic science tool for in vivo studies on man and a unique tool for clinical diagnoses of metabolic disorders. At present, nuclear magnetic resonance is considered safe if access to the magnet environment is controlled. Technological advances employing field strengths over 2 teslas will require biophysical studies of heating and static field effects.

  19. Nuclear Resonant Surface Diffraction of Synchrotron Radiation

    NASA Astrophysics Data System (ADS)

    Schlage, Kai; Dzemiantsova, Liudmila; Bocklage, Lars; Wille, Hans-Christian; Pues, Matthias; Meier, Guido; Röhlsberger, Ralf

    2017-06-01

    Nuclear resonant x-ray diffraction in grazing incidence geometry is used to determine the lateral magnetic configuration in a one-dimensional lattice of ferromagnetic nanostripes. During magnetic reversal, strong nuclear superstructure diffraction peaks appear in addition to the electronic ones due to an antiferromagnetic order in the nanostripe lattice. We show that the analysis of the angular distribution together with the time dependence of the resonantly diffracted x rays reveals surface spin structures with very high sensitivity. This scattering technique provides unique access to laterally correlated spin configurations in magnetically ordered nanostructures and, in perspective, also to their dynamics.

  20. Nuclear Resonant Surface Diffraction of Synchrotron Radiation.

    PubMed

    Schlage, Kai; Dzemiantsova, Liudmila; Bocklage, Lars; Wille, Hans-Christian; Pues, Matthias; Meier, Guido; Röhlsberger, Ralf

    2017-06-09

    Nuclear resonant x-ray diffraction in grazing incidence geometry is used to determine the lateral magnetic configuration in a one-dimensional lattice of ferromagnetic nanostripes. During magnetic reversal, strong nuclear superstructure diffraction peaks appear in addition to the electronic ones due to an antiferromagnetic order in the nanostripe lattice. We show that the analysis of the angular distribution together with the time dependence of the resonantly diffracted x rays reveals surface spin structures with very high sensitivity. This scattering technique provides unique access to laterally correlated spin configurations in magnetically ordered nanostructures and, in perspective, also to their dynamics.

  1. Principles of nuclear magnetic resonance for medical application.

    PubMed

    Rosen, B R; Brady, T J

    1983-10-01

    Several important components must be combined to create an effective nuclear magnetic resonance (NMR) imaging system. The most imposing component is the magnet itself, which is most often either resistive or superconducting. In addition, the magnetic field gradient, radiofrequency (RF) coil, spectrometer, computer, and display system are critical factors that require special consideration before selecting an NMR system for a particular clinical usage. Although nuclear magnetic resonance and nuclear decay share a common object of interest (the nucleus), a number of differences between resonance and decay phenomena relating to information content and imaging techniques can be discussed. First, in NMR the frequency, and hence energy, of the detected electromagnetic radiation from a given nuclear type is dependent critically on the magnetic and molecular environment of the stimulated nuclei. This is contrasted to the situation in nuclear decay reactions, where the energy of gamma or positron emission is only weakly dependent on local factors. Thus in NMR, molecular information can be acquired without the use of external tracer molecules. In NMR energy exchange mechanisms (relaxation) take place on a microscopic scale, and hence local information is acquired by measuring relaxation times. Furthermore, the frequency output of an NMR experiment is transmitted to the detector with little change from its surroundings. This again differs from nuclear decay, where the observed spread of detected energies is a complex function of numerous interactions among the emitted radiation, the surrounding matter, and the detector, and energy exchange processes are spread in a random fashion over a large volume. However, this relative lack of interaction with matter in NMRs (RF) output comes at a price of sensitivity, since the energy level is orders of magnitude lower than that of gamma photons. In addition, the much longer wavelengths associated with such low energy radiation (on the

  2. Applications Using High Flux LCS gamma-ray Beams: Nuclear Security and Contributions to Fukushima

    NASA Astrophysics Data System (ADS)

    Fujiwara, Mamoru

    2014-09-01

    Nuclear nonproliferation and security are an important issue for the peaceful use of nuclear energy. Many countries now collaborate together for preventing serious accidents from nuclear terrorism. Detection of hidden long-lived radioisotopes and fissionable nuclides in a non-destructive manner is useful for nuclear safeguards and management of nuclear wastes as well as nuclear security. After introducing the present situation concerning the nuclear nonproliferation and security in Japan, we plan to show the present activities of JAEA to detect the hidden nuclear materials by means of the nuclear resonance fluorescence with energy-tunable, monochromatic gamma-rays generated by Laser Compton Scattering (LCS) with an electron beam. The energy recovery linac (ERL) machine is now under development with the KEK-JAEA collaboration for realizing the new generation of gamma-ray sources. The detection technologies of nuclear materials are currently developed using the existing electron beam facilities at Duke University and at NewSubaru. These developments in Japan will contribute to the nuclear security program in Japan and to the assay of melted nuclear fuels in the Fukushima Daiichi nuclear power plants.

  3. Method for determining fast-alpha-particle confinement in tokamak plasmas using resonant nuclear reactors

    SciTech Connect

    Cecil, F.E.; Zweben, S.J.; Medley, S.S.

    1986-03-01

    The resonant nuclear reactions D(..cap alpha..,..gamma..)/sup 6/Li, /sup 6/Li(..cap alpha..,..gamma..)/sup 10/B, and /sup 7/Li(..cap alpha..,..gamma..)/sup 11/B are examined as diagnostics of fast-alpha-particle confinement in tokamak plasmas. Gamma rays from these resonant reactions with energies from 2.1 MeV to 9.2 MeV may be used to infer the alpha-particle population between energies of 0.4 MeV and 2.6 MeV. The ratio of these alpha-burnup reactions to the reactions T(D,..gamma..)/sup 5/He and /sup 3/He(D,..gamma..)/sup 5/Li provides a technique for the measurement of alpha confinement.

  4. Advanced Laser-Compton Gamma-Ray Sources for Nuclear Materials Detection, Assay and Imaging

    NASA Astrophysics Data System (ADS)

    Barty, C. P. J.

    2015-10-01

    Highly-collimated, polarized, mono-energetic beams of tunable gamma-rays may be created via the optimized Compton scattering of pulsed lasers off of ultra-bright, relativistic electron beams. Above 2 MeV, the peak brilliance of such sources can exceed that of the world's largest synchrotrons by more than 15 orders of magnitude and can enable for the first time the efficient pursuit of nuclear science and applications with photon beams, i.e. Nuclear Photonics. Potential applications are numerous and include isotope-specific nuclear materials management, element-specific medical radiography and radiology, non-destructive, isotope-specific, material assay and imaging, precision spectroscopy of nuclear resonances and photon-induced fission. This review covers activities at the Lawrence Livermore National Laboratory related to the design and optimization of mono-energetic, laser-Compton gamma-ray systems and introduces isotope-specific nuclear materials detection and assay applications enabled by them.

  5. Nuclear Magnetic Resonance Technology for Medical Studies.

    ERIC Educational Resources Information Center

    Budinger, Thomas F.; Lauterbur, Paul C.

    1984-01-01

    Reports on the status of nuclear magnetic resonance (NMR) from theoretical and clinical perspectives, reviewing NMR theory and relaxation parameters relevant to NMR imaging. Also reviews literature related to modern imaging strategies, signal-to-noise ratio, contrast agents, in vivo spectroscopy, spectroscopic imaging, clinical applications, and…

  6. Sample spinner for nuclear magnetic resonance spectrometer

    SciTech Connect

    Stejskal, E.O.

    1984-05-01

    A sample spinner for a nuclear magnetic resonance spectrometer having improved operating characteristics is described comprising a rotor supported at both ends by support gas bearings and positioned by a thrust gas bearing. Improved support gas bearings are also described which result in a spinner exhibiting long-term stable operation characteristics.

  7. Nuclear Magnetic Resonance Technology for Medical Studies.

    ERIC Educational Resources Information Center

    Budinger, Thomas F.; Lauterbur, Paul C.

    1984-01-01

    Reports on the status of nuclear magnetic resonance (NMR) from theoretical and clinical perspectives, reviewing NMR theory and relaxation parameters relevant to NMR imaging. Also reviews literature related to modern imaging strategies, signal-to-noise ratio, contrast agents, in vivo spectroscopy, spectroscopic imaging, clinical applications, and…

  8. Simple and Inexpensive Classroom Demonstrations of Nuclear Magnetic Resonance and Magnetic Resonance Imaging.

    ERIC Educational Resources Information Center

    Olson, Joel A.; Nordell, Karen J.; Chesnik, Marla A.; Landis, Clark R.; Ellis, Arthur B.; Rzchowski, M. S.; Condren, S. Michael; Lisensky, George C.

    2000-01-01

    Describes a set of simple, inexpensive, classical demonstrations of nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) principles that illustrate the resonance condition associated with magnetic dipoles and the dependence of the resonance frequency on environment. (WRM)

  9. Simple and Inexpensive Classroom Demonstrations of Nuclear Magnetic Resonance and Magnetic Resonance Imaging.

    ERIC Educational Resources Information Center

    Olson, Joel A.; Nordell, Karen J.; Chesnik, Marla A.; Landis, Clark R.; Ellis, Arthur B.; Rzchowski, M. S.; Condren, S. Michael; Lisensky, George C.

    2000-01-01

    Describes a set of simple, inexpensive, classical demonstrations of nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) principles that illustrate the resonance condition associated with magnetic dipoles and the dependence of the resonance frequency on environment. (WRM)

  10. Nature of the Pygmy Resonance in Continuous Gamma-Spectra

    SciTech Connect

    Rekstad, J; Siem, S; Bernstein, L; Schiller, A; Garrett, P; Nelson, R; Guttormsen, M; Algin, E; Voinov, A

    2003-12-01

    Two-step-cascade spectra of the {sup 171}Yb(n, {gamma}{gamma}){sup 172}Yb reaction have been measured using thermal neutrons. They are compared to calculations based on experimental values of the level density and radiative strength function obtained from the {sup 173}Yb({sup 3}He,{alpha}{gamma}){sup 172}Yb reaction. The multipolarity of a 6.5(15) {mu}{sub N}{sup 2} resonance at 3.3(1) MeV in the strength function is determined to be M1 by this comparison.

  11. [Nuclear magnetic resonance in psychiatry].

    PubMed

    Hamad, H

    1993-01-01

    Magnetic Resonance Imaging (MRI) is a more recent technique than computerized tomography (CT), with which morphological, high quality, three-dimensional images can be obtained, it is capable of differentiating gray/white matter without patients' exposure to radiation. Clinical investigation studies demonstrate the following findings: In Schizophrenics: Enlargement of lateral ventricles volume in 67-73%, in naive patients 21-33%. The increase of the third ventricle varies from 19 to 73%, whose patients have significant flat affect. The temporal lobe gray matter is reduced, including amygdala-hippocampal complex, and parahippocampal gyrus. No specific corpus callosum results are concluded. There is cortical atrophy, specially of bilateral prefrontal regions. Basal ganglia (lenticular and caudate nuclei) are increased. The prefrontal, temporal and limbic dysfunction supports the abnormal connection hypothesis in schizophrenics. Basal ganglia also are involved in the pathogenesis of the disease. Clinical cortical atrophy symptoms are demonstrated by neuropsychological tests, although some cognitive deficits are remediable. Perinatal complications are more frequent, in children who will be schizophrenics, than their siblings (23.6% vs 12.8%); those of special interest are: toxemia, prematurity, long labor, jaundice and bleeding during pregnancy. In affective Bipolar Disorders: There is increase (19-50%) in the number of focal signal hyperintensities at the lateral limits of ventricles and in both hemispheres, and a trend towards larger ventricular size. The temporal lobe is smaller bilaterally, but the right side is 15% larger; its volume correlates negatively with long-term illness in males. In Unipolar Disorder an increase of frontal white matter T1 values is registered.(ABSTRACT TRUNCATED AT 250 WORDS)

  12. Optically pumped nuclear magnetic resonance of semiconductors.

    PubMed

    Hayes, Sophia E; Mui, Stacy; Ramaswamy, Kannan

    2008-02-07

    Optically pumped NMR (OPNMR) of direct gap and indirect gap semiconductors has been an area of active research interest, motivated by both basic science and technological perspectives. Proposals to enhance and to spatially localize nuclear polarization have stimulated interest in this area. Recent progress in OPNMR has focused on exploring the experimental parameter space in order to elucidate details of the underlying photophysics of optical pumping phenomena. The focus of this review is on recent studies of bulk samples of GaAs and InP, namely, the photon energy dependence, the magnetic field dependence, and the phase dependence of OPNMR resonances. Models for the development of nuclear polarization are discussed.

  13. Nuclear Resonance Fluorescence Response of U-235

    NASA Astrophysics Data System (ADS)

    Warren, Glen

    2008-05-01

    Nuclear resonance fluorescence (NRF) is a physical process that provides an isotopic-specific signature that could be used for the identification and characterization of materials. The technique involves the detection of prompt discrete-energy photons emitted from a sample, which is exposed to photons in the MeV energy range. Potential applications of the technique range from detection of high explosives to characterization of special nuclear materials. Pacific Northwest National Laboratory and Passport Systems have collaboratively conducted a set of measurements to search for an NRF response of U-235 in the 1.5 to 9 MeV energy range. Results from these measurements will be presented.

  14. Nuclear resonance fluorescence of {sup 237}Np

    SciTech Connect

    Angell, C. T.; Yee, R.; Joshi, T. H.; Swanberg, E.; Norman, E. B.; Hicks, C. L. Jr.; Klimenko, A.; Korbly, S.; Wilson, C.; Kulp, W. D.; Warren, G. A.; Bray, T. H.; Copping, R.; Glans, P. A.; Tyliszczak, T.; Shuh, D. K.

    2010-11-15

    Measurements of states excited by nuclear resonance fluorescence in {sup 237}Np were performed using a bremsstrahlung beam. Fifteen new states were observed in the region of 1.7 to 2.5 MeV. They can be used to detect or assay {sup 237}Np nondestructively for applications in security and safeguards. The states are populated with similar strength as those states found previously in {sup 235}U and {sup 239}Pu but are spread out more in energy.

  15. Neutron monitoring systems including gamma thermometers and methods of calibrating nuclear instruments using gamma thermometers

    DOEpatents

    Moen, Stephan Craig; Meyers, Craig Glenn; Petzen, John Alexander; Foard, Adam Muhling

    2012-08-07

    A method of calibrating a nuclear instrument using a gamma thermometer may include: measuring, in the instrument, local neutron flux; generating, from the instrument, a first signal proportional to the neutron flux; measuring, in the gamma thermometer, local gamma flux; generating, from the gamma thermometer, a second signal proportional to the gamma flux; compensating the second signal; and calibrating a gain of the instrument based on the compensated second signal. Compensating the second signal may include: calculating selected yield fractions for specific groups of delayed gamma sources; calculating time constants for the specific groups; calculating a third signal that corresponds to delayed local gamma flux based on the selected yield fractions and time constants; and calculating the compensated second signal by subtracting the third signal from the second signal. The specific groups may have decay time constants greater than 5.times.10.sup.-1 seconds and less than 5.times.10.sup.5 seconds.

  16. Nuclear magnetic resonance spectrometer and method

    SciTech Connect

    Peterson, P.E.; Vidrine, D.W.

    1981-08-18

    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.

  17. Nuclear Resonance Fluorescence for Materials Assay

    SciTech Connect

    Quiter, Brian J.; Ludewigt, Bernhard; Mozin, Vladimir; Prussin, Stanley

    2009-06-29

    This paper discusses the use of nuclear resonance fluorescence (NRF) techniques for the isotopic and quantitative assaying of radioactive material. Potential applications include age-dating of an unknown radioactive source, pre- and post-detonation nuclear forensics, and safeguards for nuclear fuel cycles Examples of age-dating a strong radioactive source and assaying a spent fuel pin are discussed. The modeling work has ben performed with the Monte Carlo radiation transport computer code MCNPX, and the capability to simulate NRF has bee added to the code. Discussed are the limitations in MCNPX?s photon transport physics for accurately describing photon scattering processes that are important contributions to the background and impact the applicability of the NRF assay technique.

  18. Nuclear Resonance Fluorescence for Materials Assay

    SciTech Connect

    Quiter, Brian; Ludewigt, Bernhard; Mozin, Vladimir; Prussin, Stanley

    2009-06-05

    This paper discusses the use of nuclear resonance fluorescence (NRF) techniques for the isotopic and quantitative assaying of radioactive material. Potential applications include age-dating of an unknown radioactive source, pre- and post-detonation nuclear forensics, and safeguards for nuclear fuel cycles Examples of age-dating a strong radioactive source and assaying a spent fuel pin are discussed. The modeling work has ben performed with the Monte Carlo radiation transport computer code MCNPX, and the capability to simulate NRF has bee added to the code. Discussed are the limitations in MCNPX's photon transport physics for accurately describing photon scattering processes that are important contributions to the background and impact the applicability of the NRF assay technique.

  19. Resonantly Detecting Axion-Mediated Forces with Nuclear Magnetic Resonance

    NASA Astrophysics Data System (ADS)

    Arvanitaki, Asimina; Geraci, Andrew A.

    2014-10-01

    We describe a method based on precision magnetometry that can extend the search for axion-mediated spin-dependent forces by several orders of magnitude. By combining techniques used in nuclear magnetic resonance and short-distance tests of gravity, our approach can substantially improve upon current experimental limits set by astrophysics, and probe deep into the theoretically interesting regime for the Peccei-Quinn (PQ) axion. Our method is sensitive to PQ axion decay constants between 109 and 1012 GeV or axion masses between 10-6 and 10-3 eV, independent of the cosmic axion abundance.

  20. Prompt Gamma Emission in Resonance Neutron Induced Fission of 239Pu

    NASA Astrophysics Data System (ADS)

    Ruskov, I.; Kopatch, Yu. N.; Panteleev, Ts.; Skoy, V. R.; Shvetsov, V. N.; Dermendjiev, E.; Janeva, N.; Pikelner, L. B.; Grigoriev, Yu. V.; Mezentseva, Zh. V.; Ivanov, I.

    The scientific interest in the resonance neutron induced capture and fission reactions on 239Pu is continuously rising during the last decade. From a practical point of view, this is because more precise data on capture and fission cross sections, fission fragment mass and kinetic energy distributions, variation of prompt fission neutron and gamma yields in the resonance neutron region, are needed for the modelling of new generation nuclear power plants and for nuclear spent fuel and waste transmutation. From a heuristic and fundamental point of view, such a research improves our knowledge and understanding of the fission phenomena itself. To achieve these goals more powerful neutron sources and more precise fission product detectors have to be used. At the Joint Institute for Nuclear Research (JINR) Frank Laboratory of Neutron Physics (FLNP), where already half a century the thermal and resonance neutron induced nuclear reactions are studied, a new electron accelerator driven white spectrum pulsed neutron source IREN has been built and successfully tested. The improved characteristics of this facility, in comparison with those of the former pulse neutron fast reactor IBR-30, will allow measuring some of the neutron-nuclear reaction data with better precision and accuracy. A new experimental setup for detecting gamma rays (and neutrons) has been designed and is under construction. It will consist of 2 rings (arrays) of 12 NaI(Tl) detectors each (or 1 array of 24 detectors) with variable ring diameter and distance between both rings. Such a setup will make possible not only to measure the multiplicity, energy and angular anisotropy of prompt fission gammas, but also to separate the contribution of prompt fission neutrons by their longer time-of-flight from the fissile target to the detectors. The signals from all the 24 detectors will be recorded simultaneously in digitized form and will be stored on the hard disk of the personal computer for further off

  1. Pulsed Photofission Delayed Gamma Ray Detection for Nuclear Material Identification

    SciTech Connect

    John Kavouras; Xianfei Wen; Daren R. Norman; Dante R. Nakazawa; Haori Yang

    2012-11-01

    Innovative systems with increased sensitivity and resolution are in great demand to detect diversion and to prevent misuse in support of nuclear materials management for the U.S. fuel cycle. Nuclear fission is the most important multiplicative process involved in non-destructive active interrogation. This process produces the most easily recognizable signature for nuclear materials. High-energy gamma rays can also excite a nucleus and cause fission through a process known as photofission. After photofission reactions, delayed signals are easily distinguishable from the interrogating radiation. Linac-based, advanced inspection techniques utilizing the fission signals after photofission have been extensively studied for homeland security applications. Previous research also showed that a unique delayed gamma ray energy spectrum exists for each fissionable isotope. Isotopic composition measurement methods based on delayed gamma ray spectroscopy will be the primary focus of this work.

  2. Nuclear magnetic resonance properties of lunar samples.

    NASA Technical Reports Server (NTRS)

    Kline, D.; Weeks, R. A.

    1972-01-01

    Nuclear magnetic resonance spectra of Na-23, Al-27, and P-31 in fines samples 10084,60 and 14163,168 and in crystalline rock samples 12021,55 and 14321,166, have been recorded over a range of frequencies up to 20 MHz. A shift in the field at which maximum absorption occurs for all of the spectra relative to the field at which maximum absorption occurs for terrestrial analogues is attributed to a sample-dependent magnetic field at the Na, Al, and P sites opposing the laboratory field. The magnitude of these fields internal to the samples is sample dependent and varies from 5 to 10 G. These fields do not correlate with the iron content of the samples. However, the presence of single-domain particles of iron distributed throughout the plagioclase fraction that contains the principal fraction of Na and Al is inferred from electron magnetic resonance spectra shapes.

  3. Nuclear quadrupole resonance echoes from hexamethylenetetramine.

    PubMed

    Ota, Go; Itozaki, Hideo

    2006-10-01

    We investigated the echo phenomenon of nuclear quadrupole resonance (NQR) from hexamethylenetetramine (HMT). We detected the pure NQR echo signal of HMT with a short pulse interval. The intensity of the echo signal increased as the pulse interval time was decreased. We observed that a clean echo signal was generated even when the pulse interval was shorter than the decay time constant T(2)(*). Since the short interval time gives a strong echo, our result insists that shorter interval time is preferred for the NQR detection.

  4. Study of (178m2)hafnium(gamma, gamma')(178)hafnium reaction by nuclear spectroscopy methods

    NASA Astrophysics Data System (ADS)

    Rusu, Claudiu

    Controlled release of the energy stored in nuclear isomers is very attractive for producing powerful sources of induced gamma-ray radiation. High-energy nuclear isomers can have very long lifetimes of the order of years and thus they can serve as good energy storage media. For instance, 1 mg of the 178m2Hf isomer stores about 1 MJ as excitation energy of the isomeric state. One of the most promising ways to release the energy stored in the isomeric state involves photonuclear reactions in the energy range of soft X-rays. Photons with energies lower than 20 keV can excite the 178m2Hf isomeric state to an intermediate level from which gamma transitions cascade to lower levels with a decay rate much faster than the rate of spontaneous decay of the isomeric state. In this work, the photoexcitation of 178m2Hf by (gamma, gamma ') reactions at low energies was studied by nuclear spectroscopy methods. The experimental arrangement was based on the coincident detection of gamma photons with four large HPGe detectors. A bremsstrahlung X-ray generator was used as excitation source, which covered a continuous energy-range from 0 to 60 keV. The interpretation of the experimental results shows that the decay of the 178m2Hf isomer can be triggered by X-rays at a power on the order of only mW/cm 2. The analysis of the gamma-gamma coincidence data has revealed that during X-ray irradiations, a line of 129.5 keV was found in coincidence with the 213.4 keV ground state band (GSB) transition. The 129.5 keV line has not been previously observed and is not a known transition of the spontaneous decay of 178m2Hf. The 129.5 keV gamma transition must be a member of a sequence of gamma transitions that bypasses most of the normal decay cascade populated by spontaneous decay. This result leads to a deeper understanding of the (gamma, gamma ') reactions at low energies. These photonuclear reactions are of special interest because of the importance of possible practical applications. The studies

  5. Satellite observation of atmospheric nuclear gamma radiation

    NASA Technical Reports Server (NTRS)

    Letaw, John R.; Share, G. H.; Kinzer, R. L.; Silberberg, R.; Chupp, E. L.

    1989-01-01

    Satellite observations of the spectrum of gamma radiation from the earth's atmosphere in the energy interval from 300 keV to 8.5 MeV were obtained with a gamma-ray spectrometer during 1980-1983. A total of 20 atmospheric line features are superimposed on a continuum background which is modeled using a power law with an index of -1.16. The line energies and intensities are consistent with production by secondary neutrons interacting with atmospheric N-14 and O-16. The intensity and spectrum of photons at energies below the 511-keV line, in excess of a power law continuum, are explained by Compton scattering of the annihilation line photons in traversing an average of 21 g/sq cm of atmosphere.

  6. Nuclear structure studies with gamma-ray beams

    DOE PAGES

    Tonchev, Anton; Bhatia, Chitra; Kelley, John; ...

    2015-05-28

    In stable and weakly bound neutron-rich nuclei, a resonance-like concentration of dipole states has been observed for excitation energies below the neutron-separation energy. This clustering of strong dipole states has been named the Pygmy Dipole Resonance (PDR) in contrast to the Giant Dipole Resonance (GDR) that dominates the E1 response. Understanding the PDR is presently of great interest in nuclear structure and nuclear astrophysics. High-sensitivity studies of E1 and M1 transitions in closed-shell nuclei using monoenergetic and 100% linearly-polarized photon beams are presented.

  7. A Monte Carlo simulation to study a design of a gamma-ray detector for neutron resonance densitometry

    NASA Astrophysics Data System (ADS)

    Tsuchiya, H.; Harada, H.; Koizumi, M.; Kitatani, F.; Takamine, J.; Kureta, M.; Iimura, H.

    2013-11-01

    Neutron resonance densitometry (NRD) has been proposed to quantify nuclear materials in melted fuel (MF) that will be removed from the Fukushima Daiichi nuclear power plant. The problem is complex due to the expected presence of strong neutron absorbing impurities such as 10B and high radiation field that is mainly caused by 137Cs. To identify the impurities under the high radiation field, NRD is based on a combination of neutron resonance transmission analysis (NRTA) and neutron resonance capture analysis (NRCA). We investigated with Geant4 the performance of a gamma-ray detector for NRCA in NRD. The gamma-ray detector has a well shape, consisting of cylindrical and tube type LaBr3 scintillators. We show how it measures 478 keV gamma rays derived from 10B(n, αγ) reaction in MF under a high 137Cs-radiation environment. It was found that the gamma-ray detector was able to well suppress the Compton edge of 662-keV gamma rays of 137Cs and had a high peak-to-Compton continuum ratio, by using the tube type scintillator as a back-catcher detector. Then, we demonstrate that with this ability, detection of 478-keV gamma rays from 10B is accomplished in realistic measuring time.

  8. Nuclear probes and intraoperative gamma cameras.

    PubMed

    Heller, Sherman; Zanzonico, Pat

    2011-05-01

    Gamma probes are now an important, well-established technology in the management of cancer, particularly in the detection of sentinel lymph nodes. Intraoperative sentinel lymph node as well as tumor detection may be improved under some circumstances by the use of beta (negatron or positron), rather than gamma detection, because the very short range (∼ 1 mm or less) of such particulate radiations eliminates the contribution of confounding counts from activity other than in the immediate vicinity of the detector. This has led to the development of intraoperative beta probes. Gamma camera imaging also benefits from short source-to-detector distances and minimal overlying tissue, and intraoperative small field-of-view gamma cameras have therefore been developed as well. Radiation detectors for intraoperative probes can generally be characterized as either scintillation or ionization detectors. Scintillators used in scintillation-detector probes include thallium-doped sodium iodide, thallium- and sodium-doped cesium iodide, and cerium-doped lutecium orthooxysilicate. Alternatives to inorganic scintillators are plastic scintillators, solutions of organic scintillation compounds dissolved in an organic solvent that is subsequently polymerized to form a solid. Their combined high counting efficiency for beta particles and low counting efficiency for 511-keV annihilation γ-rays make plastic scintillators well-suited as intraoperative beta probes in general and positron probes in particular Semiconductors used in ionization-detector probes include cadmium telluride, cadmium zinc telluride, and mercuric iodide. Clinical studies directly comparing scintillation and semiconductor intraoperative probes have not provided a clear choice between scintillation and ionization detector-based probes. The earliest small field-of-view intraoperative gamma camera systems were hand-held devices having fields of view of only 1.5-2.5 cm in diameter that used conventional thallium

  9. An introduction to nuclear magnetic resonance in biomedicine.

    PubMed

    Andrew, E R

    1990-02-01

    In this paper the author illustrates the historical aspects of the development, first, of the fundamental principles of nuclear magnetic resonance and, second, the extension of these principles to magnetic resonance imaging and in vivo spectroscopy.

  10. Characterization of nuclear material by Neutron Resonance Transmission Analysis

    NASA Astrophysics Data System (ADS)

    Paradela, C.; Alaerts, G.; Becker, B.; Heyse, J.; Kopecky, S.; Moens, A.; Mondelaers, W.; Schillebeeckx, P.; Wynants, R.; Harada, H.; Kitatani, F.; Koizumi, M.; Tsuchiya, H.

    2016-11-01

    The use of Neutron Resonance Transmission Analysis for the characterization of nuclear materials is discussed. The method, which relies on resonance structures in neutron-induced reaction cross sections, can be applied as a non-destructive method to characterise complex nuclear materials such as melted fuel resulting from a severe nuclear accident. Results of a demonstration experiment at the GELINA facility reveal that accurate data can be obtained at a compact facility even in the case of strong overlapping resonances.

  11. AKAP7gamma is a nuclear RI-binding AKAP.

    PubMed

    Brown, Rebecca L; August, Shelley L; Williams, Carmen J; Moss, Stuart B

    2003-06-27

    Spatial regulation of protein kinase A (PKA) is accomplished by its sequestration via A-kinase anchor proteins (AKAPs). PKA activity is critical for mammalian oocyte development, suggesting that PKA must be appropriately positioned in these large cells. A screen for AKAPs in oocytes identified AKAP7gamma, an AKAP originally found in pancreas. Yeast two-hybrid analysis and co-immunoprecipitation studies showed that AKAP7gamma bound the type I PKA regulatory subunit (RI) and that the RI-binding domain overlapped the previously identified type II PKA regulatory subunit (RII) binding domain. Overexpressed AKAP7gamma localized to the nuclei of HEK 293 cells via a nuclear localization signal. In addition, endogenous AKAP7gamma protein was found in both the nucleus and cytoplasm of oocytes. This work identifies AKAP7gamma as the first nuclear AKAP to bind RI and suggests that AKAP7gamma may be responsible for positioning PKA via RI and/or RII to regulate PKA-mediated gene transcription in both somatic cells and oocytes.

  12. Nuclear Magnetic Resonance Imaging. South Carolina Health Service Area 2

    SciTech Connect

    Not Available

    1984-12-01

    Contents include: Nuclear Magnetic Resonance Imaging (NMRI); (Clinical applications, Magnet types, Comparisons with other systems, Manpower, Manufacturers, Contraindications); Analysis of systems; (Availability, Accessibility, Cost, Quality, Continuity, Acceptability).

  13. Crystal ball studies of giant resonance gamma decay

    NASA Astrophysics Data System (ADS)

    Beene, J. R.; Bertrand, F. E.; Halbert, M. L.

    1985-01-01

    We have carried out coincidence experiments to investigate the photon and neutron emission from the giant resonance region in 208Pb and 90Zr using the ORNL Spin Spectrometer, a 72-segment NaI detector system. States in 208Pb and 90Zr were excited by inelastic scattering of 380-MeV 17O. We have determined the total gamma-decay probability, the ground-state gamma branching ratio, and the branching ratios to a number of low-lying stats as a function of excitation energy in 208Pb to ˜15 MeV. Especially interesting observations include the absence of a significant branch from the giant quadrupole resonance to the 3- state at 2.6 MeV, a strong branch from this resonance to a 3- state at 4.9 MeV, and the dominance of decays to various 1- states at 5-7 MeV from the region around 14 MeV of excitation (E0 resonances). Comparable but less complete data were also obtained on 90Zr.

  14. Dynamic Nuclear Spin Resonance in n-GaAs

    NASA Astrophysics Data System (ADS)

    Chen, Y. S.; Reuter, D.; Wieck, A. D.; Bacher, G.

    2011-10-01

    The dynamics of optically detected nuclear magnetic resonance is studied in n-GaAs via time-resolved Kerr rotation using an on-chip microcoil for rf field generation. Both optically allowed and optically forbidden NMR are observed with a dynamics controlled by the interplay between dynamic nuclear polarization via hyperfine interaction with optically generated spin-polarized electrons and nuclear spin depolarization due to magnetic resonance absorption. Comparing the characteristic nuclear spin relaxation rate obtained in experiment with master equation simulations, the underlying nuclear spin depolarization mechanism for each resonance is extracted.

  15. Nuclear gamma rays from compact objects. [nuclear interactions around neutron stars and black holes

    NASA Technical Reports Server (NTRS)

    Lingenfelter, R. E.; Higdon, J. C.; Ramaty, R.

    1978-01-01

    Accreting compact objects may be important gamma ray line sources and may explain recent observations of celestial gamma-ray line emission from a transient source in the direction of the galactic anti-center, from the galactic center, and possibly from the radio galaxy Centaurus A. The identification of the lines from the transient source requires a strong redshift. Such a redshift permits the identification of these lines with the most intense nuclear emission lines expected in nature, positron annihilation, and neutron capture on hydrogen and iron. Their production as a result of nuclear interactions in accreting gas around a neutron star is proposed. The gamma-ray line emission from the galactic center and possibly Centaurus A appears to have a surprisingly high luminosity, amounting to perhaps as much as 10% of the total luminosity of these sources. Such high gamma-ray line emission efficiencies could result from nuclear interactions in accreting gas around a massive black hole.

  16. Using Nuclear Resonance Fluorescence for Nondestructive Isotopic Analysis

    SciTech Connect

    Ludewigt, Bernhard A.; Mozin, Vladimir; Haefner, Andrew; Quiter, Brian

    2010-07-14

    Nuclear resonance fluorescence (NRF) has been studied as one of the nondestructive analysis (NDA) techniques currently being investigated by a multi-laboratory collaboration for the determination of Pu mass in spent fuel. In NRF measurements specific isotopes are identified by their characteristic lines in recorded gamma spectra. The concentration of an isotope in a material can be determined from measured NRF signal intensities if NRF cross sections and assay geometries are known. The potential of NRF to quantify isotopic content and Pu mass in spent fuel has been studied. The addition of NRF data to MCNPX and an improved treatment of the elastic photon scattering at backward angles has enabled us to more accurately simulate NRF measurements on spent fuel assemblies. Using assembly models from the spent fuel assembly library generated at LANL, NRF measurements are simulated to find the best measurement configurations, and to determine measurement sensitivities and times, and photon source and gamma detector requirements. A first proof-of-principal measurement on a mock-up assembly with a bremsstrahlung photon source demonstrated isotopic sensitivity to approximately 1% limited by counting statistics. Data collection rates are likely a limiting factor of NRF-based measurements of fuel assemblies but new technological advances may lead to drastic improvements.

  17. Nuclear Resonance Fluorescence off 54Cr: The Onset of the Pygmy Dipole Resonance

    NASA Astrophysics Data System (ADS)

    Ries, P. C.; Beck, T.; Beller, J.; Krishichayan; Gayer, U.; Isaak, J.; Löher, B.; Mertes, L.; Pai, H.; Pietralla, N.; Romig, C.; Savran, D.; Schilling, M.; Tornow, W.; Werner, V.; Zweidinger, M.

    2016-06-01

    Low-lying electric and magnetic dipole excitations (E1 and M1) below the neutron separation threshold, particularly the Pygmy Dipole Resonance (PDR), have drawn considerable attention in the last years. So far, mostly moderately heavy nuclei in the mass regions around A = 90 and A = 140 were examined with respect to the PDR. In the present work, the systematics of the PDR have been extended by measuring excitation strengths and parity quantum numbers of J = 1 states in lighter nuclei near A = 50 in order to gather information on the onset of the PDR. The nuclei 50,52,54Cr and 48,50Ti were examined via bremsstrahlung produced at the DArmstadt Superconducting electron Linear Accelerator (S-DALINAC) with photon energies up to 9.7 MeV with the method of nuclear resonance fluorescence. Numerous excited states were observed, many of which for the first time. The parity quantum numbers of these states have been determined at the High Intensity Gamma-ray Source (HIγS) of the Triangle Universities Nuclear Laboratory in Durham, NC, USA. Informations to the methods and the experimental setups will be provided and the results on 54Cr achieved will be discussed with respect to the onset of the PDR.

  18. Small-Volume Nuclear Magnetic Resonance Spectroscopy

    NASA Astrophysics Data System (ADS)

    Fratila, Raluca M.; Velders, Aldrik H.

    2011-07-01

    Nuclear magnetic resonance (NMR) spectroscopy is one of the most information-rich analytical techniques available. However, it is also inherently insensitive, and this drawback precludes the application of NMR spectroscopy to mass- and volume-limited samples. We review a particular approach to increase the sensitivity of NMR experiments, namely the use of miniaturized coils. When the size of the coil is reduced, the sample volume can be brought down to the nanoliter range. We compare the main coil geometries (solenoidal, planar, and microslot/stripline) and discuss their applications to the analysis of mass-limited samples. We also provide an overview of the hyphenation of microcoil NMR spectroscopy to separation techniques and of the integration with lab-on-a-chip devices and microreactors.

  19. Nanoscale nuclear magnetic resonance with chemical resolution

    NASA Astrophysics Data System (ADS)

    Aslam, Nabeel; Pfender, Matthias; Neumann, Philipp; Reuter, Rolf; Zappe, Andrea; Fávaro de Oliveira, Felipe; Denisenko, Andrej; Sumiya, Hitoshi; Onoda, Shinobu; Isoya, Junichi; Wrachtrup, Jörg

    2017-07-01

    Nuclear magnetic resonance (NMR) spectroscopy is a key analytical technique in chemistry, biology, and medicine. However, conventional NMR spectroscopy requires an at least nanoliter-sized sample volume to achieve sufficient signal. We combined the use of a quantum memory and high magnetic fields with a dedicated quantum sensor based on nitrogen vacancy centers in diamond to achieve chemical shift resolution in 1H and 19F NMR spectroscopy of 20-zeptoliter sample volumes. We demonstrate the application of NMR pulse sequences to achieve homonuclear decoupling and spin diffusion measurements. The best measured NMR linewidth of a liquid sample was ~1 part per million, mainly limited by molecular diffusion. To mitigate the influence of diffusion, we performed high-resolution solid-state NMR by applying homonuclear decoupling and achieved a 20-fold narrowing of the NMR linewidth.

  20. In vivo nuclear magnetic resonance imaging

    NASA Technical Reports Server (NTRS)

    Leblanc, A.; Evans, H.; Bryan, R. N.; Johnson, P.; Schonfeld, E.; Jhingran, S. G.

    1984-01-01

    A number of physiological changes have been demonstrated in bone, muscle and blood after exposure of humans and animals to microgravity. Determining mechanisms and the development of effective countermeasures for long duration space missions is an important NASA goal. The advent of tomographic nuclear magnetic resonance imaging (NMR or MRI) gives NASA a way to greatly extend early studies of this phenomena in ways not previously possible; NMR is also noninvasive and safe. NMR provides both superb anatomical images for volume assessments of individual organs and quantification of chemical/physical changes induced in the examined tissues. The feasibility of NMR as a tool for human physiological research as it is affected by microgravity is demonstrated. The animal studies employed the rear limb suspended rat as a model of mucle atrophy that results from microgravity. And bedrest of normal male subjects was used to simulate the effects of microgravity on bone and muscle.

  1. Nuclear magnetic resonance imaging of the spine

    SciTech Connect

    Modic, M.T.; Weinstein, M.A.; Pavlicek, W.; Starnes, D.L.; Duchesneau, P.M.; Boumphrey, F.; Hardy, R.J. Jr.

    1984-01-01

    Forty subjects were examined to determine the accuracy and clinical usefulness of nuclear magnetic resonance (NMR) examination of the spine. The NMR images were compared with plain radiographs, high-resolution computed tomograms, and myelograms. The study included 15 patients with normal spinal cord anatomy and 25 patients whose pathological conditions included canal stenosis, herniated discs, metastatic tumors, primary cord tumor, trauma, Chiari malformations, syringomyelia, and developmental disorders. Saturation recovery images were best in differentiating between soft tissue and cerebrospinal fluid. NMR was excellent for the evaluation of the foramen magnum region and is presently the modality of choice for the diagnosis of syringomyelia and Chiari malformation. NMR was accurate in diagnosing spinal cord trauma and spinal canal block.

  2. Nuclear Resonance Fluorescence Using Different Photon Sources

    SciTech Connect

    Warren, Glen A.; Caggiano, Joseph A.; Ahmed, Mohammad; Bertozzi, William; Hunt, Alan W.; Johnson, James; Jones, James L.; Korbly, Steve; Reedy, Edward; Seipel, Heather; Stave, Sean; Watson, Scott; Weller, Henry

    2008-11-14

    Abstract–Nuclear resonance fluorescence (NRF) is a photon-based active interrogation approach that provides isotope-specific signatures that can be used to detect and characterize samples. As NRF systems are designed to address specific appli¬cations, an obvious first question to address is the type of photon source to be employed for the application. Our collaboration has conducted a series of NRF measurements using different photon sources to begin to examine this issue. The measurements were designed to be as similar as possible to facilitate a straightforward comparison of the different sources. Measurements were conducted with a high-duty factor electron accelerator using bremsstrahlung photons, with a pulsed linear accelerator using bremsstrahlung photons, and with a narrow bandwidth photon source using Compton backscattered photons. We present our observations on the advantages and disadvantages of each photon source type. Issues such as signal rate, the signal-to-noise ratio, and absorbed dose are discussed.

  3. Explosives detection by nuclear quadrupole resonance (NQR)

    NASA Astrophysics Data System (ADS)

    Garroway, Allen N.; Buess, Michael L.; Yesinowski, James P.; Miller, Joel B.; Krauss, Ronald A.

    1994-10-01

    Pure nuclear quadrupole resonance (NQR) of 14N nuclei is quite promising as a method for detecting explosives such as RDX and contraband narcotics such as cocaine and heroin in quantities of interest. Pure NQR is conducted without an external applied magnetic field, so potential concerns about damage to magnetically encoded data or exposure of personnel to large magnetic fields are not relevant. Because NQR frequencies of different compounds are quite distinct, we do not encounter false alarms from the NQR signals of other benign materials. We have constructed a laboratory prototype NQR explosives detector which interrogates a volume of 300 liters (10 ft3). This paper presents abbreviated results from a demonstration of the laboratory prototype NQR explosives detector conducted at the Federal Aviation Administration Technical Center in May 1994 on RDX-based explosives.

  4. Geochemical Controls on Nuclear Magnetic Resonance Measurements

    SciTech Connect

    Knight, Rosemary; Prasad, Manika; Keating, Kristina

    2003-11-11

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

  5. Nuclear magnetic resonance imaging in medicine

    PubMed Central

    McKinstry, C S

    1986-01-01

    Using the technique of nuclear magnetic resonance (NMR, MR, MRI), the first images displaying pathology in humans were published in 1980.1 Since then, there has been a rapid extension in the use of the technique, with an estimated 225 machines in use in the USA at the end of 1985.2 Considerable enthusiasm has been expressed for this new imaging technique,3 although awareness of its high cost in the present economic climate has led to reservations being expressed in other quarters.2 The aim of this article is to give an outline of the present state of NMR, and indicate some possible future developments. ImagesFig 1Fig 2Fig 3(a)Fig 3 (b)Fig 4Fig 5Fig 6Fig 7 (a)Fig 7 (b)Fig 8Fig 9Fig 10 PMID:3811023

  6. Nuclear magnetic resonance imaging of liver hemangiomas

    SciTech Connect

    Sigal, R.; Lanir, A.; Atlan, H.; Naschitz, J.E.; Simon, J.S.; Enat, R.; Front, D.; Israel, O.; Chisin, R.; Krausz, Y.

    1985-10-01

    Nine patients with cavernous hemangioma of the liver were examined by nuclear magnetic resonance imaging (MRI) with a 0.5 T superconductive magnet. Spin-echo technique was used with varying time to echo (TE) and repetition times (TR). Results were compared with /sup 99m/Tc red blood cell (RBC) scintigraphy, computed tomography (CT), echography, and arteriography. Four illustrated cases are reported. It was possible to establish a pattern for MRI characteristics of cavernous hemangiomas; rounded or smooth lobulated shape, marked increase in T1 and T2 values as compared with normal liver values. It is concluded that, although more experience is necessary to compare the specificity with that of ultrasound and CT, MRI proved to be very sensitive for the diagnosis of liver hemangioma, especially in the case of small ones which may be missed by /sup 99m/Tc-labeled RBC scintigraphy.

  7. Capture Gamma-Ray Libraries for Nuclear Applications

    SciTech Connect

    Sleaford, B.W.; Firestone, Richard B.; Summers, N.; Escher, J.; Hurst, A.; Krticka, M.; Basunia, S.; Molnar, G.; Belgya, T.; Revay, Z.; Choi, H.D.

    2010-05-01

    The neutron capture reaction is useful in identifying and analyzing the gamma-ray spectrum from an unknown assembly as it gives unambiguous information on its composition. This can be done passively or actively where an external neutron source is used to probe an unknown assembly. There are known capture gamma-ray data gaps in the ENDF libraries used by transport codes for various nuclear applications. The Evaluated Gamma-ray Activation file (EGAF) is a new thermal neutron capture database of discrete line spectra and cross sections for over 260 isotopes that was developed as part of an IAEA Coordinated Research Project. EGAF has been used to improve the capture gamma production in ENDF libraries. For medium to heavy nuclei the quasi continuum contribution to the gamma cascades is not experimentally resolved. The continuum contains up to 90percent of all the decay energy an is modeled here with the statistical nuclear structure code DICEBOX. This code also provides a consistency check of the level scheme nuclear structure evaluation. The calculated continuum is of sufficient accuracy to include in the ENDF libraries. This analysis also determines new total thermal capture cross sections and provides an improved RIPL database. For higher energy neutron capture there is less experimental data available making benchmarking of the modeling codes more difficult. We use CASINO, a version of DICEBOX that is modified for this purpose. This can be used to simulate the neutron capture at incident neutron energies up to 20 MeV to improve the gamma-ray spectrum in neutron data libraries used for transport modelling of unknown assemblies.

  8. Neutron Capture Gamma-Ray Libraries for Nuclear Applications

    SciTech Connect

    Sleaford, B W; Firestone, R B; Summers, N; Escher, J; Hurst, A; Krticka, M; Basunia, S; Molnar, G; Belgya, T; Revay, Z; Choi, H D

    2010-11-04

    The neutron capture reaction is useful in identifying and analyzing the gamma-ray spectrum from an unknown assembly as it gives unambiguous information on its composition. this can be done passively or actively where an external neutron source is used to probe an unknown assembly. There are known capture gamma-ray data gaps in the ENDF libraries used by transport codes for various nuclear applications. The Evaluated Gamma-ray Activation file (EGAF) is a new thermal neutron capture database of discrete line spectra and cross sections for over 260 isotopes that was developed as part of an IAEA Coordinated Research project. EGAF is being used to improve the capture gamma production in ENDF libraries. For medium to heavy nuclei the quasi continuum contribution to the gamma cascades is not experimentally resolved. The continuum contains up to 90% of all the decay energy and is modeled here with the statistical nuclear structure code DICEBOX. This code also provides a consistency check of the level scheme nuclear structure evaluation. The calculated continuum is of sufficient accuracy to include in the ENDF libraries. This analysis also determines new total thermal capture cross sections and provides an improved RIPL database. For higher energy neutron capture there is less experimental data available making benchmarking of the modeling codes more difficult. They are investigating the capture spectra from higher energy neutrons experimentally using surrogate reactions and modeling this with Hauser-Feshbach codes. This can then be used to benchmark CASINO, a version of DICEBOX modified for neutron capture at higher energy. This can be used to simulate spectra from neutron capture at incident neutron energies up to 20 MeV to improve the gamma-ray spectrum in neutron data libraries used for transport modeling of unknown assemblies.

  9. Selectivity in multiple quantum nuclear magnetic resonance

    SciTech Connect

    Warren, W.S.

    1980-11-01

    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.

  10. Gamma-ray identification of nuclear weapon materials

    SciTech Connect

    Gosnell, T. B., LLNL; Hall, J. M.; Jam, C. L.; Knapp, D. A.; Koenig, Z. M.; Luke, S. J.; Pohl, B. A.; Schach von Wittenau, A.; Wolford, J. K.

    1997-02-03

    There has been an accelerating national interest in countering nuclear smuggling. This has caused a corresponding expansion of interest in the use of gamma-ray spectrometers for checkpoint monitoring, nuclear search, and within networks of nuclear and collateral sensors. All of these are fieldable instruments--ranging from large, fixed portal monitors to hand-held and remote monitoring equipment. For operational reasons, detectors with widely varying energy resolution and detection efficiency will be employed. In many instances, such instruments must be sensitive to weak signals, always capable of recognizing the gamma-ray signatures from nuclear weapons materials (NWM), often largely insensitive to spectral alteration by radiation transport through intervening materials, capable of real-time implementation, and able to discriminate against signals from commonly encountered legitimate gamma-ray sources, such as radiopharmaceuticals. Several decades of experience in classified programs have shown that all of these properties are not easily achieved and successful approaches were of limited scope--such as the detection of plutonium only. This project was originally planned as a two-year LDRD-ER. Since funding for 1997 was not sustained, this is a report of the first year's progress.

  11. Egyptian limestone for gamma dosimetry: an electron paramagnetic resonance study

    NASA Astrophysics Data System (ADS)

    Salama, E.

    2014-04-01

    The electron paramagnetic resonance (EPR) properties of limestone from a certain Egyptian site were investigated in order to propose an efficient and low-cost gamma dosimeter. Radiation-induced free radicals were of one type which was produced in the limestone samples at g=2.0066 after exposure to gamma radiation (60Co). EPR spectrum was recorded and analyzed. The microwave power saturation curve and the effect of changing modulation amplitude on peak-to- peak signal height were investigated. The response of limestone to different radiation doses (0.5-20 kGy) was studied. Except for the decrease in signal intensities during the first five hours following irradiation, over the period of two months fair stabilities of signal intensities were noticed. From the current results, it is possible to conclude that natural limestone may be a suitable material for radiation dosimetry in the range of irradiation processing.

  12. Highly efficient D/H scrambling and highly selective chlorination in /gamma/-irradiated D- and H-octane mixture in freon 113: Trace back of transient processes by the observation of D/H scrambling with high resolution nuclear magnetic resonance

    SciTech Connect

    Okazaki, M.; Toriyama, K.; Nunome, K.

    1989-08-15

    A high resolution nuclear magnetic resonance (NMR) study on the /gamma/-irradiated isotopic mixture of protiated and deuteriated octanes in freon 113 revealed that the protons and the deuterons are scrambled very efficiently (/ital G//gt/2000) at all the positions. While the solvent freon was substituted selectively with a proton and chlorination of protiated octane occurred selectively at the secondary position. These observations, coexistence of the random D/H scrambling and the selective substitution reactions, are the evidence that: (1) in the ''hot'' period rapid intermolecular radical migration occurs among the solute alkanes, the solvent freons, and the product chloroalkanes, (2) on the other hand, in the following ''thermalized'' period, chemical bonds within which radical site migration occurs are limited to those with smaller bonding energies, i.e., the secondary position of (protiated) alkane, the C--Cl bonds of freon, and the C--Cl bond of chloroalkanes.

  13. Pulsed electron-nuclear-electron triple resonance spectroscopy

    NASA Astrophysics Data System (ADS)

    Thomann, Hans; Bernardo, Marcelino

    1990-05-01

    A new experimental technique, pulsed electron-nuclear-electron triple resonance spectroscopy, is demonstrated. It is based on a modification of the pulse sequence for electron-nuclear double resonance (ENDOR) in which two EPR and one NMR transition are irradiated. The irradiation of one EPR transition is detected via a second EPR transition. The nuclear hyperfine coupling, which separates these EPR transition frequencies, is the irradiated NMR transition. The major advantages of triple resonance spectroscopy include the ability to resolve overlapping nuclear resonances in the ENDOR spectrum and a more direct quantitative assignment of nuclear hyperfine and quadrupole couplings. The triple resonance experiment is an alternative to the recently proposed method of employing rapid magnetic field jumps between microwave pulses for generating hyperfine selective ENDOR spectra.

  14. Nuclear Quadrupole Resonance Study of Potassium - - Chloride.

    NASA Astrophysics Data System (ADS)

    Ramia, Maximo Elias

    Fast Fourier transform nuclear quadrupole resonance (NQR) was used to study the cubic antifluorite crystal potassium hexacloro-osmate, K(,2)OsCl(,6). The study of the ('35)Cl and ('37)Cl resonances were performed on three samples of K(,2)OsCl(,6), a powder sample, a powder sample recrystallized from D(,2)O and a single crystal sample. The studies were carried out in the temperature range 300 to 6K. A detailed study of the ('35)Cl and ('37)Cl NQR lineshapes, in the temperature range 70 to 300K, showed that the lineshapes reflect the strain fields produced by lattice dislocations and point defects. The temperature evolution of these strain fields give rise to a satellite line which previously was attributed to H('+) ion impurities present in the samples. A comprehensive study of the temperature evolution of the NQR spectrum in the vicinity of the phase transition revealed a drop of line intensity and the progressive appearance of an extra broad resonance component. Both effects are associated with the existence of precursor dynamic clusters at temperatures higher than T(,C). Qualitatively similar but quantitatively different behaviour was observed in the powder and single crystal samples. Although the precursor clusters are an intrinsic property of the phrase transition, their detailed dynamics is sample independent. A NQR study of the tetragonal phase showed that at the lowest temperature the ratio of line intensities is 2:1. The phase shift effect previously observed in the tetragonal phase of K(,2)ReCl(,6) was also observed in K(,2)OsCl(,6). The effect has been explained as an experimental artifact introduced by the truncation of the FID due to the spectrometer dead time. Spin-lattice relaxation measurements in the cubic phase show two component relaxation in the vicinity of T(,C). The behaviour is quantitatively different in the powder and single crystal samples. The short relaxation time is associated with dynamic clusters. Spin-lattice relaxation time

  15. Elastic properties of gamma-Pu by resonant ultrasound spectroscopy

    SciTech Connect

    Migliori, Albert; Betts, J; Trugman, A; Mielke, C H; Mitchell, J N; Ramos, M; Stroe, I

    2009-01-01

    Despite intense experimental and theoretical work on Pu, there is still little understanding of the strange properties of this metal. We used resonant ultrasound spectroscopy method to investigate the elastic properties of pure polycrystalline Pu at high temperatures. Shear and longitudinal elastic moduli of the {gamma}-phase of Pu were determined simultaneously and the bulk modulus was computed from them. A smooth linear and large decrease of all elastic moduli with increasing temperature was observed. We calculated the Poisson ratio and found that it increases from 0.242 at 519K to 0.252 at 571K.

  16. Cavity- and waveguide-resonators in electron paramagnetic resonance, nuclear magnetic resonance, and magnetic resonance imaging.

    PubMed

    Webb, Andrew

    2014-11-01

    Cavity resonators are widely used in electron paramagnetic resonance, very high field magnetic resonance microimaging and also in high field human imaging. The basic principles and designs of different forms of cavity resonators including rectangular, cylindrical, re-entrant, cavity magnetrons, toroidal cavities and dielectric resonators are reviewed. Applications in EPR and MRI are summarized, and finally the topic of traveling wave MRI using the magnet bore as a waveguide is discussed.

  17. Detection of nuclear gamma rays from Centaurus A

    NASA Technical Reports Server (NTRS)

    Hall, R. D.; Walraven, G. D.; Djuth, F. T.; Haymes, R. C.; Meegan, C. A.

    1976-01-01

    Results are reported for an observation of nuclear gamma rays in the energy range between 0.033 and 12.25 MeV from Centaurus A using a balloon-borne actively collimated NaI(Tl) crystal scintillation counter. The observing procedure is outlined, no systematic errors are found in the data, and power-law fits to the source's energy spectrum are attempted. A power law of approximately 0.86E to the -1.9 power photon/sq cm/sec per keV is shown to give an acceptable fit to the continuum, and the detection of two gamma-ray lines at 1.6 and 4.5 MeV, respectively, is discussed. It is found that the low-energy gamma-ray luminosity of Cen A is 9.4 by 10 to the 43rd power erg/sec for a distance of 5 Mpc and that Cen A is apparently variable in low-energy gamma radiation. It is suggested that the broad feature detected at 1.6 MeV may be due to three blended lines (possibly excited Ne-20, Mg-24, and Si-28), the 4.5-MeV line is most likely due to deexcitation of excited C-12, and the nuclear excitation results from either cosmic-ray bombardment of Cen A's interstellar medium or nucleosynthesis within the source.

  18. Burn injury by nuclear magnetic resonance imaging.

    PubMed

    Eising, Ernst G; Hughes, Justin; Nolte, Frank; Jentzen, Walter; Bockisch, Andreas

    2010-01-01

    Nuclear magnetic resonance imaging has become a standard diagnostic procedure in clinical medicine and is well known to have hazards for patients with pacemaker or metallic foreign bodies. Compared to CT, the frequency of MRI examinations is increasing due to the missing exposure of the patients by X-rays. Furthermore, high-field magnetic resonance tomograph (MRT) with 3 T has entered clinical practice, and 7-T systems are installed in multiple scientific institutions. On the other hand, the possibility of burn injuries has been reported only in very few cases. Based on a clinical finding of a burn injury in a 31-year-old male patient during a routine MRI of the lumbar spine with standard protocol, the MR scanner was checked and the examination was simulated in an animal model. The patient received a third-degree burn injury of the skin of the right hand and pelvis in a small region of skin contact. The subsequent control of the MRI scanner indicated no abnormal values for radiofrequency (RF) and power. In the subsequent animal experiment, comparable injuries could only be obtained by high RF power in a microwave stove. It is concluded that 'tissue loops' resulting from a contact between hand and pelvis must be avoided. With regard to forensic aspects, the need to inform patients of such a minimal risk can be avoided if the patients are adequately positioned using an isolating material between the hands and pelvis. These facts must be emphasized more in the future, if high-field MRI with stronger RF gradients is available in routine imaging. Copyright 2010 Elsevier Inc. All rights reserved.

  19. BROADBAND EXCITATION IN NUCLEAR MAGNETIC RESONANCE

    SciTech Connect

    Tycko, R.

    1984-10-01

    Theoretical methods for designing sequences of radio frequency (rf) radiation pulses for broadband excitation of spin systems in nuclear magnetic resonance (NMR) are described. The sequences excite spins uniformly over large ranges of resonant frequencies arising from static magnetic field inhomogeneity, chemical shift differences, or spin couplings, or over large ranges of rf field amplitudes. Specific sequences for creating a population inversion or transverse magnetization are derived and demonstrated experimentally in liquid and solid state NMR. One approach to broadband excitation is based on principles of coherent averaging theory. A general formalism for deriving pulse sequences is given, along with computational methods for specific cases. This approach leads to sequences that produce strictly constant transformations of a spin system. The importance of this feature in NMR applications is discussed. A second approach to broadband excitation makes use of iterative schemes, i.e. sets of operations that are applied repetitively to a given initial pulse sequences, generating a series of increasingly complex sequences with increasingly desirable properties. A general mathematical framework for analyzing iterative schemes is developed. An iterative scheme is treated as a function that acts on a space of operators corresponding to the transformations produced by all possible pulse sequences. The fixed points of the function and the stability of the fixed points are shown to determine the essential behavior of the scheme. Iterative schemes for broadband population inversion are treated in detail. Algebraic and numerical methods for performing the mathematical analysis are presented. Two additional topics are treated. The first is the construction of sequences for uniform excitation of double-quantum coherence and for uniform polarization transfer over a range of spin couplings. Double-quantum excitation sequences are demonstrated in a liquid crystal system. The

  20. MAX-a gamma-ray lense for nuclear astrophysics.

    SciTech Connect

    von Ballmoos, P.; Halloin, H.; Skinner, G.; Smither, B.; Paul, J.; Abrosimov, N.; Alvarez, J.; Astier , P.; Bastie, P.; Barrett, D.; Bazzano, A.; Blanchard, A.; Boutonnet, A.; Brousse, P.; Cordier, B.; Courvoisier, T.; DiCocco, G.; Giuliani, A.; Hamelin, B.; Hernanz, M.; Jean, P.; Isern, J.; Knodlseder, J.; Laurent, P.; Lebrun, F.; Experimental Facilities Division; CESR; CEA-Saclay; Inst. fur Kristallzuchtung; IEEC; LPNHE; Inst. Laue-Langevin; IAS; LA-OMP; Alcatel Space Industries; ISDC; TESRE; Univ. Insurbia

    2004-01-01

    The mission concept MAX is a space borne crystal diffraction telescope, featuring a broad-band Laue lens optimized for the observation of compact sources in two wide energy bands of high astrophysical relevance. For the first time in this domain, gamma-rays will be focused from the large collecting area of a crystal diffraction lens onto a very small detector volume. As a consequence, the background noise is extremely low, making possible unprecedented sensitivities. The primary scientific objective of MAX is the study of type Ia supernovae by measuring intensities, shifts and shapes of their nuclear gamma-ray lines. When finally understood and calibrated, these profoundly radioactive events will be crucial in measuring the size, shape, and age of the Universe. Observing the radioactivities from a substantial sample of supernovae and novae will significantly improve our understanding of explosive nucleosynthesis. Moreover, the sensitive gamma-ray line spectroscopy performed with MAX is expected to clarify the nature of galactic microquasars (e{sup +}e{sup -} annihilation radiation from the jets), neutrons stars and pulsars, X-ray Binaries, AGN, solar flares and, last but not least, gamma-ray afterglow from gamma-burst counterparts.

  1. Resonant Interneurons Can Increase Robustness of Gamma Oscillations

    PubMed Central

    Tikidji-Hamburyan, Ruben A.; Martínez, Joan José; White, John A.

    2015-01-01

    Gamma oscillations are believed to play a critical role in in information processing, encoding, and retrieval. Inhibitory interneuronal network gamma (ING) oscillations may arise from a coupled oscillator mechanism in which individual neurons oscillate or from a population oscillator in which individual neurons fire sparsely and stochastically. All ING mechanisms, including the one proposed herein, rely on alternating waves of inhibition and windows of opportunity for spiking. The coupled oscillator model implemented with Wang–Buzsáki model neurons is not sufficiently robust to heterogeneity in excitatory drive, and therefore intrinsic frequency, to account for in vitro models of ING. Similarly, in a tightly synchronized regime, the stochastic population oscillator model is often characterized by sparse firing, whereas interneurons both in vivo and in vitro do not fire sparsely during gamma, but rather on average every other cycle. We substituted so-called resonator neural models, which exhibit class 2 excitability and postinhibitory rebound (PIR), for the integrators that are typically used. This results in much greater robustness to heterogeneity that actually increases as the average participation in spikes per cycle approximates physiological levels. Moreover, dynamic clamp experiments that show autapse-induced firing in entorhinal cortical interneurons support the idea that PIR can serve as a network gamma mechanism. Furthermore, parvalbumin-positive (PV+) cells were much more likely to display both PIR and autapse-induced firing than GAD2+ cells, supporting the view that PV+ fast-firing basket cells are more likely to exhibit class 2 excitability than other types of inhibitory interneurons. SIGNIFICANCE STATEMENT Gamma oscillations are believed to play a critical role in information processing, encoding, and retrieval. Networks of inhibitory interneurons are thought to be essential for these oscillations. We show that one class of interneurons with an

  2. Resonant Interneurons Can Increase Robustness of Gamma Oscillations.

    PubMed

    Tikidji-Hamburyan, Ruben A; Martínez, Joan José; White, John A; Canavier, Carmen C

    2015-11-25

    Gamma oscillations are believed to play a critical role in in information processing, encoding, and retrieval. Inhibitory interneuronal network gamma (ING) oscillations may arise from a coupled oscillator mechanism in which individual neurons oscillate or from a population oscillator in which individual neurons fire sparsely and stochastically. All ING mechanisms, including the one proposed herein, rely on alternating waves of inhibition and windows of opportunity for spiking. The coupled oscillator model implemented with Wang-Buzsáki model neurons is not sufficiently robust to heterogeneity in excitatory drive, and therefore intrinsic frequency, to account for in vitro models of ING. Similarly, in a tightly synchronized regime, the stochastic population oscillator model is often characterized by sparse firing, whereas interneurons both in vivo and in vitro do not fire sparsely during gamma, but rather on average every other cycle. We substituted so-called resonator neural models, which exhibit class 2 excitability and postinhibitory rebound (PIR), for the integrators that are typically used. This results in much greater robustness to heterogeneity that actually increases as the average participation in spikes per cycle approximates physiological levels. Moreover, dynamic clamp experiments that show autapse-induced firing in entorhinal cortical interneurons support the idea that PIR can serve as a network gamma mechanism. Furthermore, parvalbumin-positive (PV(+)) cells were much more likely to display both PIR and autapse-induced firing than GAD2(+) cells, supporting the view that PV(+) fast-firing basket cells are more likely to exhibit class 2 excitability than other types of inhibitory interneurons. Gamma oscillations are believed to play a critical role in information processing, encoding, and retrieval. Networks of inhibitory interneurons are thought to be essential for these oscillations. We show that one class of interneurons with an abrupt onset of firing

  3. Nuclear magnetic resonance techniques in medicine.

    PubMed

    Bradbury, E M; Radda, G K; Allen, P S

    1983-04-01

    Nuclear magnetic resonance (NMR) techniques are now finding exciting new noninvasive applications in medicine. There are two major approaches. The first is as an analytical technique using 31P NMR spectroscopy for the identification and quantitation of the more abundant phosphate metabolites in various tissues. Changes in the levels of these metabolites and in intracellular cytoplasmic pH can be followed in various ischemic and hypoxic conditions to monitor metabolic response to stress situations and to diagnose inborn errors of metabolism. The second major approach is an entirely different application of NMR techniques and uses 1H, the nucleus most abundant in biological tissues, largely in water and fats, to produce NMR images of any section of the body. By applying non-uniform magnetic fields across a section of the body, hydrogen nuclei in different elemental volumes in the section are tagged with different frequencies and their signals can be processed to give an image of the section. In contrast to computed tomographic scanning, NMR has particularly powerful application in the imaging of soft tissues.

  4. Spatial localization in nuclear magnetic resonance spectroscopy.

    PubMed

    Keevil, Stephen F

    2006-08-21

    The ability to select a discrete region within the body for signal acquisition is a fundamental requirement of in vivo NMR spectroscopy. Ideally, it should be possible to tailor the selected volume to coincide exactly with the lesion or tissue of interest, without loss of signal from within this volume or contamination with extraneous signals. Many techniques have been developed over the past 25 years employing a combination of RF coil properties, static magnetic field gradients and pulse sequence design in an attempt to meet these goals. This review presents a comprehensive survey of these techniques, their various advantages and disadvantages, and implications for clinical applications. Particular emphasis is placed on the reliability of the techniques in terms of signal loss, contamination and the effect of nuclear relaxation and J-coupling. The survey includes techniques based on RF coil and pulse design alone, those using static magnetic field gradients, and magnetic resonance spectroscopic imaging. Although there is an emphasis on techniques currently in widespread use (PRESS, STEAM, ISIS and MRSI), the review also includes earlier techniques, in order to provide historical context, and techniques that are promising for future use in clinical and biomedical applications.

  5. High frequency electron nuclear double resonance at 239 GHz using a far-infrared laser source

    SciTech Connect

    Paschedag, L.; van Tol, J.; Wyder, P.

    1995-10-01

    We report on the application of {sup 14}N electron nuclear double resonance (ENDOR) at 8.5 T and 239 GHz ({lambda}=1.2 mm) in a {gamma}-irradiated betaine arsenate single crystal. A laser was used as a far-infrared radiation source in a transmission-type electron paramagnetic resonance (EPR) setup without a cavity. The four expected nitrogen ENDOR lines were observed, but due to insufficient saturation of the EPR transitions the signal/noise ratio was not larger than 10 and the signals vanished at temperatures above 20 K. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  6. Observation of the competitive double-gamma nuclear decay.

    PubMed

    Walz, C; Scheit, H; Pietralla, N; Aumann, T; Lefol, R; Ponomarev, V Yu

    2015-10-15

    The double-gamma (γγ)-decay of a quantum system in an excited state is a fundamental second-order process of quantum electrodynamics. In contrast to the well-known single-gamma (γ)-decay, the γγ-decay is characterized by the simultaneous emission of two γ quanta, each with a continuous energy spectrum. In nuclear physics, this exotic decay mode has only been observed for transitions between states with spin-parity quantum numbers J(π) = 0(+) (refs 1-3). Single-gamma decays-the main experimental obstacle to observing the γγ-decay-are strictly forbidden for these 0(+) → 0(+) transitions. Here we report the observation of the γγ-decay of an excited nuclear state (J(π) = 11/2(-)) that is directly competing with an allowed γ-decay (to ground state J(π) = 3/2(+)). The branching ratio of the competitive γγ-decay of the 11/2(-) isomer of (137)Ba to the ground state relative to its single γ-decay was determined to be (2.05 ± 0.37) × 10(-6). From the measured angular correlation and the shape of the energy spectra of the individual γ-rays, the contributing combinations of multipolarities of the γ radiation were determined. Transition matrix elements calculated using the quasiparticle-phonon model reproduce our measurements well. The γγ-decay rate gives access to so far unexplored important nuclear structure information, such as the generalized (off-diagonal) nuclear electric polarizabilities and magnetic susceptibilities.

  7. Integrated neutron/gamma-ray portal monitors for nuclear safeguards

    SciTech Connect

    Fehlau, P.E. )

    1994-08-01

    Radiation monitoring is one nuclear-safeguards measure used to protect against the theft of special nuclear materials (SNM) by pedestrians departing from SNM access areas. The integrated neutron/gamma-ray portal monitor is an ideal radiation monitor for the task when the SNM is plutonium. It achieves high sensitivity for detecting both bare and shielded plutonium by combining two types of radiation detector. One type is a neutron-chamber detector, comprising a large, hollow, neutron moderator that contains a single thermal-neutron proportional counter. The entrance wall of each chamber is thin to admit slow neutrons from plutonium contained in a moderating shield, while the other walls are thick to moderate fast neutrons from bare or lead-shielded plutonium so that they can be detected. The other type of detector is a plastic scintillator that is primarily for detecting gamma rays from small amounts of unshielded plutonium. The two types of detector are easily integrated by making scintillators part of the thick back wall of each neutron chamber or by inserting them into each chamber void. The authors compared the influence of the two methods of integration on detecting neutrons and gamma rays, and they examined the effectiveness of other design factors and the methods for signal detection as well.

  8. Integrated neutron/gamma-ray portal monitors for nuclear safeguards

    SciTech Connect

    Fehlau, P.E.

    1993-09-01

    Radiation monitoring is one nuclear-safeguards measure used to protect against the theft of special nuclear materials (SNM) by pedestrians departing from SNM access areas. The integrated neutron/gamma-ray portal monitor is an ideal radiation monitor for the task when the SNM is plutonium. It achieves high sensitivity for detecting both bare and shielded plutonium by combining two types of radiation detector. One type is a neutron-chamber detector, comprising a large, hollow, neutron moderator that contains a single thermal-neutron proportional counter. The entrance wall of each chamber is thin to admit slow neutrons from plutonium contained in a moderating shield, while the other walls are thick to moderate fast neutrons from bare or lead-shielded plutonium so that they can be detected. The other type of detector is a plastic scintillator that is primarily for detecting gamma rays from small amounts of unshielded plutonium. The two types of detector are easily integrated by making scintillators part of the thick back wall of each neutron chamber or by inserting them into each chamber void. We compared the influence of the two methods of integration on detecting neutrons and gamma rays, and we examined the effectiveness of other design factors and the methods for signal detection as well.

  9. Nuclear gamma-ray laser: the evolution of the idea

    SciTech Connect

    Rivlin, Lev A

    2007-08-31

    The evolution of the foreign and native search for solving the problem of a nuclear gamma-ray laser (NGL), which has been attracting attention for almost half a century despite the absence at present of any convincing data about its experimental solution, is considered. It is shown that the key conflict inherent in any conception of the NGL is the antagonism between the necessity to accumulate a sufficient amount of excited nuclei and the requirement to narrow down the emission gamma-ray line to its natural radiative width. The critical analysis of different approaches for solving this conflict (Moessbauer scheme, deeply cooled ensembles of free nuclei with the hidden inversion, nuclear inversionless amplification, two-quantum gamma emission in counterpropagating photon beams, hypothetical amplifying medium of long-lived isomers in a Bose-Einstein condensate) shows that this search is important not only due to the expected result, which could stimulate the development of quantum nucleonics as a new branch in physics, but also is of interest due to a variety of physical disciplines and experimental approaches used in this search. (invited paper)

  10. Integrated neutron/gamma-ray portal monitors for nuclear safeguards

    NASA Astrophysics Data System (ADS)

    Fehlau, Paul E.

    1994-08-01

    Radiation monitoring is one nuclear-safeguards measure used to protect against the theft of special nuclear materials (SNM) by pedestrians departing from SNM access areas. The integrated neutron/gamma-ray portal monitor is an ideal radiation monitor for the task when the SNM is plutonium. It achieves high sensitivity for detecting both bare and shielded plutonium by combining two types of radiation detector. One type is a neutron-chamber detector, comprising a large, hollow, neutron moderator that contains a single thermal-neutron proportional counter. The entrance wall of each chamber is thin to admit slow neutrons from plutonium contained in a moderating shield, while the other walls are thick to moderate fast neutrons from bare or lead-shielded plutonium so that they can be detected. The other type of detector is a plastic scintillator that is primarily for detecting gamma rays from small amounts of unshielded plutonium. The two types of detector are easily integrated by making scintillators part of the thick back wall of each neutron chamber or by inserting them into each chamber void. We compared the influence of the two methods of integration on detecting neutrons and gamma rays, and we examined the effectiveness of other design factors and the methods for signal detection as well.

  11. Multivariate analysis of gamma spectra to characterize used nuclear fuel

    NASA Astrophysics Data System (ADS)

    Coble, Jamie; Orton, Christopher; Schwantes, Jon

    2017-04-01

    The Multi-Isotope Process (MIP) Monitor provides an efficient means to monitor the process conditions in used nuclear fuel reprocessing facilities to support process verification and validation. The MIP Monitor applies multivariate analysis to gamma spectroscopy of key stages in the reprocessing stream in order to detect small changes in the gamma spectrum, which may indicate changes in process conditions. This research extends the MIP Monitor by characterizing a used fuel sample after initial dissolution according to the type of reactor of origin (pressurized or boiling water reactor; PWR and BWR, respectively), initial enrichment, burn up, and cooling time. Simulated gamma spectra were used to develop and test three fuel characterization algorithms. The classification and estimation models employed are based on the partial least squares regression (PLS) algorithm. A PLS discriminate analysis model was developed which perfectly classified reactor type for the three PWR and three BWR reactor designs studied. Locally weighted PLS models were fitted on-the-fly to estimate the remaining fuel characteristics. For the simulated gamma spectra considered, burn up was predicted with 0.1% root mean squared percent error (RMSPE) and both cooling time and initial enrichment with approximately 2% RMSPE. This approach to automated fuel characterization can be used to independently verify operator declarations of used fuel characteristics and to inform the MIP Monitor anomaly detection routines at later stages of the fuel reprocessing stream to improve sensitivity to changes in operational parameters that may indicate issues with operational control or malicious activities.

  12. Nuclear magnetic resonance for cultural heritage.

    PubMed

    Brai, Maria; Camaiti, Mara; Casieri, Cinzia; De Luca, Francesco; Fantazzini, Paola

    2007-05-01

    Nuclear magnetic resonance (NMR) portable devices are now being used for nondestructive in situ analysis of water content, pore space structure and protective treatment performance in porous media in the field of cultural heritage. It is a standard procedure to invert T(1) and T(2) relaxation data of fully water-saturated samples to get "pore size" distributions, but the use of T(2) requires great caution. It is well known that dephasing effects due to water molecule diffusion in a magnetic field gradient can affect transverse relaxation data, even if the smallest experimentally available half echo time tau is used in Carr-Purcell-Meiboom-Gill experiments. When a portable single-sided NMR apparatus is used, large field gradients due to the instrument, at the scale of the sample, are thought to be the dominant dephasing cause. In this paper, T(1) and T(2) (at different tau values) distributions were measured in natural (Lecce stone) and artificial (brick samples coming from the Greek-Roman Theatre of Taormina) porous media of interest for cultural heritage by a standard laboratory instrument and a portable device. While T(1) distributions do not show any appreciable effect from inhomogeneous fields, T(2) distributions can show strong effects, and a procedure is presented based on the dependence of 1/T(2) on tau to separate pore-scale gradient effects from sample-scale gradient effects. Unexpectedly, the gradient at the pore scale can be, in some cases, strong enough to make negligible the effects of gradients at the sample scale of the single-sided device.

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

    SciTech Connect

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

    2011-01-14

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

  14. Single-level resonance parameters fit nuclear cross-sections

    NASA Technical Reports Server (NTRS)

    Drawbaugh, D. W.; Gibson, G.; Miller, M.; Page, S. L.

    1970-01-01

    Least squares analyses of experimental differential cross-section data for the U-235 nucleus have yielded single level Breit-Wigner resonance parameters that fit, simultaneously, three nuclear cross sections of capture, fission, and total.

  15. Nuclear magnetic resonance data of C10H15

    NASA Astrophysics Data System (ADS)

    Kalinowski, H.-O.; Kumar, M.; Gupta, V.; Gupta, R.

    This document is part of Part 1 `Aliphatic Compounds' of Subvolume D 'Chemical Shifts and Coupling Constants for Carbon-13' of Landolt-Börnstein III/35 'Nuclear Magnetic Resonance Data', Group III 'Condensed Matter'.

  16. Nuclear magnetic resonance data of C9H20OSi

    NASA Astrophysics Data System (ADS)

    Mikhova, B. M.

    This document is part of Part 6 `Organic Metalloid Compounds' of Subvolume D 'Chemical Shifts and Coupling Constants for Carbon-13' of Landolt-Börnstein III/35 'Nuclear Magnetic Resonance Data', Group III 'Condensed Matter'.

  17. Nuclear magnetic resonance data of C8H18OSi

    NASA Astrophysics Data System (ADS)

    Mikhova, B. M.

    This document is part of Part 6 `Organic Metalloid Compounds' of Subvolume D 'Chemical Shifts and Coupling Constants for Carbon-13' of Landolt-Börnstein III/35 'Nuclear Magnetic Resonance Data', Group III 'Condensed Matter'.

  18. Nuclear quadrupole resonance studies in semi-metallic structures

    NASA Technical Reports Server (NTRS)

    Murty, A. N.

    1974-01-01

    Both experimental and theoretical studies are presented on spectrum analysis of nuclear quadrupole resonance of antimony and arsenic tellurides. Numerical solutions for secular equations of the quadrupole interaction energy are also discussed.

  19. Nuclear Magnetic Double Resonance Using Weak Perturbing RF Fields

    ERIC Educational Resources Information Center

    Reynolds, G. Fredric

    1977-01-01

    Describes a nuclear magnetic resonance experimental example of spin tickling; also discusses a direct approach for verifying the relative signs of coupling constants in three-spin cyclopropyl systems. (SL)

  20. Nuclear Magnetic Double Resonance Using Weak Perturbing RF Fields

    ERIC Educational Resources Information Center

    Reynolds, G. Fredric

    1977-01-01

    Describes a nuclear magnetic resonance experimental example of spin tickling; also discusses a direct approach for verifying the relative signs of coupling constants in three-spin cyclopropyl systems. (SL)

  1. FY08 Annual Report for Nuclear Resonance Fluorescence Imaging

    SciTech Connect

    Warren, Glen A.; Caggiano, Joseph A.

    2009-01-06

    FY08 annual report for project the "Nuclear Resonance Fluorescence Imaging" project. Reviews accomplishments of last 3 years, including U-235 signature search, comparison of different photon sources, and examination of NRF measurements using monochromatic photon source.

  2. A novel power amplification scheme for nuclear magnetic resonance/nuclear quadrupole resonance systems.

    PubMed

    Zhang, Xinwang; Schemm, Nathan; Balkır, Sina

    2011-03-01

    Nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR)-based chemical analysis systems have been widely utilized in various areas such as medicine, security, and academic research. In these applications, the power amplifier stage plays a key role in generating the required oscillating magnetic fields within a radio frequency coil that serves as the probe. However, the bulky size and relatively low efficiency of the traditional power amplification schemes employed present a bottleneck for the realization of compact sized and portable NMR and NQR systems. To address this problem, this work presents a class D voltage-switching power amplification scheme with novel fast-start and fast-stop functions that are suitable for generating ideal NMR and NQR excitation signals. Compared to the traditional analog power amplifiers (PAs), the proposed switched-mode PA can achieve significant improvement on the power efficiency as well as the physical volume. A PA circuit for portable NQR-based explosive detection systems has been designed and built using the proposed scheme with 1 kW possible maximum output power and 10 MHz maximum operating frequency. Test results show that the presented PA achieves more than 60% measured efficiency within a highly compact volume while sustaining fast start and stop of excitation signals in the order of microseconds.

  3. Special Nuclear Material Gamma-Ray Signatures for Reachback Analysts

    SciTech Connect

    Karpius, Peter Joseph; Myers, Steven Charles

    2016-08-29

    These are slides on special nuclear material gamma-ray signatures for reachback analysts for an LSS Spectroscopy course. The closing thoughts for this presentation are the following: SNM materials have definite spectral signatures that should be readily recognizable to analysts in both bare and shielded configurations. One can estimate burnup of plutonium using certain pairs of peaks that are a few keV apart. In most cases, one cannot reliably estimate uranium enrichment in an analogous way to the estimation of plutonium burnup. The origin of the most intense peaks from some SNM items may be indirect and from ‘associated nuclides.' Indirect SNM signatures sometimes have commonalities with the natural gamma-ray background.

  4. Don Clayton and Nuclear Gamma-Ray Astronomy

    NASA Technical Reports Server (NTRS)

    Fishman, Jerry

    2005-01-01

    For over four decades, Don Clayton has been a driving force in nuclear gamma-ray astronomy. During the 1960's, he published the first papers that gave us the scientific objectives for many balloon-borne and satellite-borne observations to come. He inspired others to work in this field as both theorists and observers. Later, he was a strong advocate for a major observatory; he helped get the Compton Gamma Ray Observatory off the ground. Over the years, he has advised and mentored many who are now among the leaders in our field. I will attempt to summarize his many contributions to theory and the interpretation of observations in this field.

  5. Neutron interrogation system using high gamma ray signature to detect contraband special nuclear materials in cargo

    DOEpatents

    Slaughter, Dennis R.; Pohl, Bertram A.; Dougan, Arden D.; Bernstein, Adam; Prussin, Stanley G.; Norman, Eric B.

    2008-04-15

    A system for inspecting cargo for the presence of special nuclear material. The cargo is irradiated with neutrons. The neutrons produce fission products in the special nuclear material which generate gamma rays. The gamma rays are detecting indicating the presence of the special nuclear material.

  6. Cyclotron resonant scattering and absorption. [in gamma ray bursts

    NASA Technical Reports Server (NTRS)

    Harding, Alice K.; Daugherty, Joseph K.

    1991-01-01

    The relativistic cross-sections for first-order absorption and second-order scattering are compared to determine the conditions under which the absorption cross-section is a good approximation to the much more complex scattering cross-section for purposes of modeling cyclotron lines in gamma-ray bursts. Differences in both the cross-sections and the line profiles are presented for a range of field strengths, angles, and electron temperatures. The relative difference of the cross-sections at one line width from resonance was found to increase with field strength and harmonic number. The difference is also strongly dependent on the photon angle to the magnetic field. For the field strength, 1.7 x 10 to the 12th G, and the angle inferred from the Ginga burst features, absorption is an excellent approximation for the profiles at the first and second harmonics.

  7. Hyperfine selectivity using multiquantum electron-nuclear-electron triple resonance

    NASA Astrophysics Data System (ADS)

    Christidis, T. C.; Mchaourab, Hassane S.; Hyde, James S.

    1996-06-01

    Hyperfine selectivity is demonstrated in a continuous wave electron-nuclear double resonance (ENDOR) experiment. A multiquantum electron-electron double resonance (ELDOR) signal is monitored as a function of the nuclear radio frequency. The signs and relative intensities of the ENDOR lines permit separating the case where both ELDOR and ENDOR frequencies match hyperfine couplings from the cases where this condition is not satisfied.

  8. Nuclear astrophysics with gamma-ray line observations

    NASA Astrophysics Data System (ADS)

    Diehl, Roland

    Gamma-ray spectrometers with high spectral resolution have been operated in space since 2002. Major efforts to understand instrumental response and backgrounds are a requird before detailed science interpretations can be derived; by now, high-resolution line-shape studies have resulted in significant astrophysical constraints, not only through studies of solar-flare details, but also for nuclear processes in the Galaxy: 44Ti from the Cas A supernova could only be detected in the low-energy lines at 68 and 78 keV, the 1157 keV line from the same decay is not seen; this constrains 44Ti ejection in core collapse supernovae. Diffuse nucleosynthesis is studied through 26 Al, 60Fe, and positron annihilation gamma-ray measurements. The gamma-ray line from decay of radioactive 26Al could be measured at unpredecented spectroscopic precision. The new determination of the total mass of 26Al produced by stellar sources throughout the Galaxy yields 2.8 ±0.9 M , and the interstellar medium around 26Al sources appears characterized by velocities in the ~100 km s-1 region. 60Fe is clearly detected with SPI, its intensity ratio to 26Al of ~15% is on the lower side of predictions from massive-star and supernova nucleosynthesis models. Nucleosynthesis sources are probably minor contributors to Galactic positrons; this may be deduced from the bulge-centered spatial distribution of the annihilation gamma-ray emission, considering that nucleosynthesis sources are expected to populate mainly the disk part of the Galaxy. It is evident that new views at nuclear and astrophysical processes in and around cosmic sources are being provided through these space missions.

  9. Investigations in cosmic and gamma ray astronomy and nuclear instruments

    NASA Astrophysics Data System (ADS)

    Gregory, J. C.

    1982-06-01

    The Nuclear Radiation Monitor (NRM) is flying on the Spacelab 2 vehicle as part of a set of instrumentation designed to measure the ambient physical environment on Spacelab in orbit. The NRM measures the natural and induced gamma ray activity. The instrument is constituted of a 25 sq in (NaI (T1)) crystal viewed with a single phototube and surrounded by a plastic anticoincidence shield. It is mounted on a pedestal and placed, with its electronics, on the Spacelab pallet. The detector head was designed and a development model fabricated and tested. Extensive software studies for on board and GSE microprocessors for use with the NRM were also made.

  10. Investigations in cosmic and gamma ray astronomy and nuclear instruments

    NASA Technical Reports Server (NTRS)

    Gregory, J. C.

    1982-01-01

    The Nuclear Radiation Monitor (NRM) is flying on the Spacelab 2 vehicle as part of a set of instrumentation designed to measure the ambient physical environment on Spacelab in orbit. The NRM measures the natural and induced gamma ray activity. The instrument is constituted of a 25 sq in (NaI (T1)) crystal viewed with a single phototube and surrounded by a plastic anticoincidence shield. It is mounted on a pedestal and placed, with its electronics, on the Spacelab pallet. The detector head was designed and a development model fabricated and tested. Extensive software studies for on board and GSE microprocessors for use with the NRM were also made.

  11. Searching for string resonances in e{sup +}e{sup -} and {gamma}{gamma} collisions

    SciTech Connect

    Anchordoqui, Luis A.; Huang Xing; Feng Wanzhe; Goldberg, Haim; Taylor, Tomasz R.

    2011-05-15

    If the fundamental mass scale of superstring theory is as low as a few TeVs, the massive modes of vibrating strings, Regge excitations, will be copiously produced at the Large Hadron Collider (LHC). We discuss the complementary signals of low-mass superstrings at the proposed electron-positron facility (CLIC), in e{sup +}e{sup -} and {gamma}{gamma} collisions. We examine all relevant four-particle amplitudes evaluated at the center-of-mass energies near the mass of lightest Regge excitations and extract the corresponding pole terms. The Regge poles of all four-point amplitudes, in particular, the spin content of the resonances, are completely model-independent, universal properties of the entire landscape of string compactifications. We show that {gamma}{gamma}{yields}e{sup +}e{sup -} scattering proceeds only through a spin-2 Regge state. We estimate that for this particular channel, string scales as high as 4 TeV can be discovered at the 11{sigma} level with the first fb{sup -1} of data collected at a center-of-mass energy {approx_equal}5 TeV. We also show that for e{sup +}e{sup -} annihilation into fermion-antifermion pairs, string theory predicts the precise value, equal to 1/3, of the relative weight of spin 2 and spin 1 contributions. This yields a dimuon angular distribution with a pronounced forward-backward asymmetry, which will help distinguishing between low-mass strings and other beyond the standard model scenarios.

  12. Nuclear gamma-ray laser: A comparative analysis of various schemes

    NASA Astrophysics Data System (ADS)

    Rivlin, L. A.; Zadernovsky, A. A.

    2010-05-01

    Four basic schemes for a nuclear gamma-ray laser (NGL) are analyzed using the “NGL-hyper-bola” as a generalized comparative criterion: solid state Mössbauer scheme; stimulated gamma-emission in cooled ensembles of free nuclei with hidden population inversion of nuclear states; nuclear gamma-ray lasing without inversion; and Bose-Einstein condensate as a hypothetical active medium for NGL.

  13. 197Au(n,gamma) Cross Section in the Unresolved Resonance Region

    SciTech Connect

    Lederer, C.; Koehler, Paul Edward

    2011-03-01

    The cross section of the reaction {sup 197}Au(n,{gamma}) was measured with the time-of-flight technique at the n{_}TOF (neutron time-of-flight) facility in the unresolved resonance region between 5 and 400 keV using a pair of C{sub 6}D{sub 6} (where D denotes {sup 2}H) liquid scintillators for the detection of prompt capture {gamma} rays. The results with a total uncertainty of 3.9%-6.7% for a resolution of 20 bins per energy decade show fair agreement with the Evaluated Nuclear Data File Version B-VII.0 (ENDF/B-VII.0), which contains the standard evaluation. The Maxwellian-averaged cross section (MACS) at 30 keV is in excellent agreement with the one according to the ENDF/B-VII.0 evaluation and 4.7% higher than the MACS measured independently by activation technique. Structures in the cross section, which had also been reported earlier, have been interpreted as being due to clusters of resonances.

  14. The Dawn of Nuclear Photonics with Laser-based Gamma-rays

    SciTech Connect

    Barty, C J

    2011-03-17

    A renaissance in nuclear physics is occurring around the world because of a new kind of incredibly bright, gamma-ray light source that can be created with short pulse lasers and energetic electron beams. These highly Mono-Energetic Gamma-ray (MEGa-ray) sources produce narrow, laser-like beams of incoherent, tunable gamma-rays and are enabling access and manipulation of the nucleus of the atom with photons or so called 'Nuclear Photonics'. Just as in the early days of the laser when photon manipulation of the valence electron structure of the atom became possible and enabling to new applications and science, nuclear photonics with laser-based gamma-ray sources promises both to open up wide areas of practical isotope-related, materials applications and to enable new discovery-class nuclear science. In the United States, the development of high brightness and high flux MEGa-ray sources is being actively pursued at the Lawrence Livermore National Laboratory in Livermore (LLNL), California near San Francisco. The LLNL work aims to create by 2013 a machine that will advance the state of the art with respect to source the peak brightness by 6 orders of magnitude. This machine will create beams of 1 to 2.3 MeV photons with color purity matching that of common lasers. In Europe a similar but higher photon energy gamma source has been included as part of the core capability that will be established at the Extreme Light Infrastructure Nuclear Physics (ELI-NP) facility in Magurele, Romania outside of Bucharest. This machine is expected to have an end point gamma energy in the range of 13 MeV. The machine will be co-located with two world-class, 10 Petawatt laser systems thus allowing combined intense-laser and gamma-ray interaction experiments. Such capability will be unique in the world. In this talk, Dr. Chris Barty from LLNL will review the state of the art with respect to MEGa-ray source design, construction and experiments and will describe both the ongoing projects

  15. Chiral discrimination in nuclear magnetic resonance spectroscopy.

    PubMed

    Lazzeretti, Paolo

    2017-08-08

    Chirality is a fundamental property of molecules whose spatial symmetry is characterized by the absence of improper rotations, making them not superimposable to their mirror image. Chiral molecules constitute the elementary building blocks of living species and one enantiomer is in general favoured (e.g., L-aminoacids and D-sugars pervade terrestrial homochiral biochemistry), because most chemical reactions producing natural substances are enantioselective. Since the effect of chiral chemicals and drugs on living beings can be markedly different between enantiomers, the quest for practical spectroscopical methods to scrutinize chirality is an issue of great importance and interest. Nuclear magnetic resonance (NMR) is a topmost analytical technique, but spectrometers currently used are ``blind'' to chirality, i.e., %%In fact, spectrometers presently used in NMR are unable to discriminate the two mirror-image forms of a chiral molecule, because, in the absence of a chiral solvent, the spectral parameters, chemical shifts and spin-spin coupling constants, are identical for enantiomers. Therefore, the development of new procedures for routine chiral recognition would offer basic support to scientists. However, in the presence of magnetic fields, a distinction between {\\em true} and {\\em false} chirality is mandatory. The former epitomizes natural optical activity, which is rationalized by a time-even pseudoscalar, i.e., the trace of a second-rank tensor, the mixed electric dipole/mag\\-net\\-ic dipole polarizability. The Faraday effect, magnetic circular dichroism and magnetic optical activity are instead related to a time-odd axial vector. The present review summarizes recent theoretical and experimental efforts to discriminate enantiomers via NMR spectroscopy, with the focus on the deep connection between chirality

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

    SciTech Connect

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

    1996-09-01

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

  17. Contraband Detection with Nuclear Resonance Fluorescence: Feasibility and Impact

    SciTech Connect

    Pruet, J; Lange, D

    2007-01-03

    In this report they show that cargo interrogation systems developed to thwart trafficking of illicit nuclear materials could also be powerful tools in the larger fight against contraband smuggling. In particular, in addition to detecting special nuclear materials, cargo scanning systems that exploit nuclear resonance fluorescence to detect specific isotopes can be used to help find: chemical weapons; some drugs as well as some chemicals regulated under the controlled substances act; precious metals; materials regulated under export control laws; and commonly trafficked fluorocarbons.

  18. A gamma-ray verification system for special nuclear material

    SciTech Connect

    Lanier, R.G.; Prindle, A.L.; Friensehner, A.V.; Buckley, W.M.

    1994-07-01

    The Safeguards Technology Program at the Lawrence Livermore National Laboratory (LLNL) has developed a gamma-ray screening system for use by the Materials Management Section of the Engineering Sciences Division at LLNL for verifying the presence or absence of special nuclear material (SNM) in a sample. This system facilitates the measurements required under the ``5610`` series of US Department of Energy orders. MMGAM is an intelligent, menu driven software application that runs on a personal computer and requires a precalibrated multi-channel analyzer and HPGe detector. It provides a very quick and easy-to-use means of determining the presence of SNM in a sample. After guiding the operator through a menu driven set-up procedure, the system provides an on-screen GO/NO-GO indication after determining the system calibration status. This system represents advances over earlier used systems in the areas of ease-of use, operator training requirements, and quality assurance. The system records the gamma radiation from a sample using a sequence of measurements involving a background measurement followed immediately by a measurement of the unknown sample. Both spectra are stored and available for analysis or output. In the current application, the presence of {sup 235}U, {sup 238}U, {sup 239}Pu, and {sup 208}Tl isotopes are indicated by extracting, from the stored spectra, four energy ``windows`` preset around gamma-ray lines characteristic of the radioactive decay of these nuclides. The system is easily extendible to more complicated problems.

  19. Mini gamma cameras for intra-operative nuclear tomographic reconstruction.

    PubMed

    Matthies, Philipp; Gardiazabal, José; Okur, Aslı; Vogel, Jakob; Lasser, Tobias; Navab, Nassir

    2014-12-01

    Nuclear imaging modalities like PET or SPECT are in extensive use in medical diagnostics. In a move towards personalized therapy, we present a flexible nuclear tomographic imaging system to enable intra-operative SPECT-like 3D imaging. The system consists of a miniaturized gamma camera mounted on a robot arm for flexible positioning, while spatio-temporal localization is provided by an optical tracking system. To facilitate statistical tomographic reconstruction of the radiotracer distribution using a maximum likelihood approach, a precise model of the mini gamma camera is generated by measurements. The entire system is evaluated in a series of experiments using a hot spot phantom, with a focus on criteria relevant for the intra-operative workflow, namely the number of required imaging positions as well as the required imaging time. The results show that high quality reconstructed images of simple hot spot configurations with positional errors of less than one millimeter are possible within acquisition times as short as 15s.

  20. Nuclear magnetic resonance spectroscopy with single spin sensitivity

    PubMed Central

    Müller, C.; Kong, X.; Cai, J.-M.; Melentijević, K.; Stacey, A.; Markham, M.; Twitchen, D.; Isoya, J.; Pezzagna, S.; Meijer, J.; Du, J. F.; Plenio, M. B.; Naydenov, B.; McGuinness, L. P.; Jelezko, F.

    2014-01-01

    Nuclear magnetic resonance spectroscopy and magnetic resonance imaging at the ultimate sensitivity limit of single molecules or single nuclear spins requires fundamentally new detection strategies. The strong coupling regime, when interaction between sensor and sample spins dominates all other interactions, is one such strategy. In this regime, classically forbidden detection of completely unpolarized nuclei is allowed, going beyond statistical fluctuations in magnetization. Here we realize strong coupling between an atomic (nitrogen–vacancy) sensor and sample nuclei to perform nuclear magnetic resonance on four 29Si spins. We exploit the field gradient created by the diamond atomic sensor, in concert with compressed sensing, to realize imaging protocols, enabling individual nuclei to be located with Angstrom precision. The achieved signal-to-noise ratio under ambient conditions allows single nuclear spin sensitivity to be achieved within seconds. PMID:25146503

  1. Resonance and continuum Gamow shell model with realistic nuclear forces

    NASA Astrophysics Data System (ADS)

    Sun, Z. H.; Wu, Q.; Zhao, Z. H.; Hu, B. S.; Dai, S. J.; Xu, F. R.

    2017-06-01

    Starting from realistic nuclear forces, we have developed a core Gamow shell model which can describe resonance and continuum properties of loosely-bound or unbound nuclear systems. To describe properly resonance and continuum, the Berggren representation has been employed, which treats bound, resonant and continuum states on equal footing in a complex-momentum (complex-k) plane. To derive the model-space effective interaction based on realistic forces, the full Q ˆ -box folded-diagram renormalization has been, for the first time, extended to the nondegenerate complex-k space. The CD-Bonn potential is softened by using the Vlow-k method. Choosing 16O as the inert core, we have calculated sd-shell neutron-rich oxygen isotopes, giving good descriptions of both bound and resonant states. The isotopes 25,26O are calculated to be resonant even in their ground states.

  2. Polywater: proton nuclear magnetic resonance spectrum.

    PubMed

    Page, T F; Jakobsen, R J; Lippincott, E R

    1970-01-02

    In the presence of water, the resonance of the strongly hydrogenbonded protons characteristic of polywater appears at 5 parts per million lower applied magnetic field than water. Polywater made by a new method confirms the infrared spectrum reported originally.

  3. Single Nuclear Spin Magnetic Resonance Force Microscopy

    DTIC Science & Technology

    2010-05-02

    Lab. In work not directly supported by this grant, these projects advanced MRFM detected Ferromagnetic Resonance ( FMR ) to enable studies of...directly supported by this grant, these projects advanced MRFM detected Ferromagnetic Resonance ( FMR ) to enable studies of submicron magnetic structures...our earlier NMR detection of 19F spins in CaF2 we have conducted 65Cu, 63Cu NMR stud- ies for studies of interface phenomena in multilayered magnetic

  4. Suitability of nuclear medicine gamma cameras as gamma spectrometers in the event of a radiological emergency

    NASA Astrophysics Data System (ADS)

    Engdahl, J. C.; Bharwani, K.

    2005-11-01

    Nuclear medicine gamma cameras are large area NaI(Tl) scintillation detectors that measure both the position and energy of incident gamma rays. A typical, commercial, large field-of-view (LFOV), gamma camera has about 2000 cm 3 of useful detector volume with an entrance window of 50×40 cm 2 by 1 cm thickness. A 3″×3″ NaI(Tl) detector, by comparison, has 17.4% of the volume and 2.3% of the area of the LFOV gamma camera. A 2002 survey reported 11,700 gamma cameras as being installed in hospitals and clinics in the US. In the event of a radiological emergency, the ability to utilize some of this installed detector capacity would be desirable. This work investigates the feasibility of using the gamma camera as a large area gamma spectrometer for detecting and quantifying isotopes likely to be involved in a radiological emergency caused by dispersion of radioactivity by a so called "dirty bomb." Monte Carlo modeling was used to analyze detection sensitivity as a function of energy for the camera vs. the 3″×3″ cylinder. For a point source positioned 100 cm from the face of the detector, the ratio of total extrinsic efficiency of the camera to that of the 3″×3″ cylinder varied from 40.3 at 140 keV to 7.3 at 5 MeV. Ratios for extrinsic efficiency of peaks (including the full energy peak, single escape, and double escape peaks) varied from 41.1 at 140 keV to 5.5 at 5 MeV. Modifications that will be required to enable the cameras to function as spectrometers over a wide energy range are described and discussed. Given the large sensitivity advantage, the fact that the camera is shielded on three sides, and that cameras are already present at many locations to where victims of a disaster would be transported, it is desirable that such system capabilities be investigated.

  5. Nuclear Magnetic Resonance and the BCS Theory

    NASA Astrophysics Data System (ADS)

    Slichter, Charles P.

    The author describes the inspiration for the experiment by Hebel and Slichter to measure the nuclear spin-lattice relaxation time in super-conductors, the design considerations for the experiment, the surprising experimental results, their theoretical treatment using the Bardeen-Cooper-Schrieffer theory, and how comparing the nuclear relaxation results with those for ultrasound absorption confirmed the central idea of the BCS theory, the BCS pair wave function.

  6. Dynamic nuclear polarization in a magnetic resonance force microscope experiment.

    PubMed

    Issac, Corinne E; Gleave, Christine M; Nasr, Paméla T; Nguyen, Hoang L; Curley, Elizabeth A; Yoder, Jonilyn L; Moore, Eric W; Chen, Lei; Marohn, John A

    2016-04-07

    We report achieving enhanced nuclear magnetization in a magnetic resonance force microscope experiment at 0.6 tesla and 4.2 kelvin using the dynamic nuclear polarization (DNP) effect. In our experiments a microwire coplanar waveguide delivered radiowaves to excite nuclear spins and microwaves to excite electron spins in a 250 nm thick nitroxide-doped polystyrene sample. Both electron and proton spin resonance were observed as a change in the mechanical resonance frequency of a nearby cantilever having a micron-scale nickel tip. NMR signal, not observable from Curie-law magnetization at 0.6 T, became observable when microwave irradiation was applied to saturate the electron spins. The resulting NMR signal's size, buildup time, dependence on microwave power, and dependence on irradiation frequency was consistent with a transfer of magnetization from electron spins to nuclear spins. Due to the presence of an inhomogeneous magnetic field introduced by the cantilever's magnetic tip, the electron spins in the sample were saturated in a microwave-resonant slice 10's of nm thick. The spatial distribution of the nuclear polarization enhancement factor ε was mapped by varying the frequency of the applied radiowaves. The observed enhancement factor was zero for spins in the center of the resonant slice, was ε = +10 to +20 for spins proximal to the magnet, and was ε = -10 to -20 for spins distal to the magnet. We show that this bipolar nuclear magnetization profile is consistent with cross-effect DNP in a ∼10(5) T m(-1) magnetic field gradient. Potential challenges associated with generating and using DNP-enhanced nuclear magnetization in a nanometer-resolution magnetic resonance imaging experiment are elucidated and discussed.

  7. Locking electron spins into resonance by electron-nuclear feedback

    NASA Astrophysics Data System (ADS)

    Nowack, Katja

    2009-03-01

    All basic building blocks for spin-based quantum information processing using electron spins in GaAs quantum dots have recently been realized. Recent experiments have shown single-shot read-out of an individual spin [1], the implementation of the SWAP gate [2] and (magnetically induced) coherent single electron spin rotations [3]. However, the main drawback of using electron spins in a GaAs environment is the short spin coherence time, which is measured to be in the nanosecond range [2,4]. The source of this fast decoherence is the hyperfine interaction of the localized electron spin with the randomly fluctuating nuclear spins of the host lattice. The fluctuations of the nuclear spins have to be reduced to extend the electron spin coherence time. We therefore study the electron-nuclear spin interaction and use magnetically driven spin resonance to control the electron spin and indirectly manipulate the nuclear spins. We apply continuous microwave excitation to the electron spin and observe strong electron-nuclear feedback. One experimental signature of this feedback is the locking of the electron spin system into resonance with the microwaves. Once the electron spin is locked into resonance, this resonance condition remains fullfilled even when the external magnetic field or the microwave frequency is changed. This is due to dynamically build up nuclear polarizations (up to 500 mT) which generally counteract the external magnetic field. Locking of the electron spin system into resonance might indicate that the nuclear polarization exhibits stable configurations where fluctuations of the nuclear distribution are reduced [5]. [4pt] References [0pt] [1] J. M. Elzerman et al. , Nature 430, 431 (2004) [0pt] [2]. J. R. Petta et al., Science 309, 2180 (2005). [0pt] [3] F. H. L. Koppens et al., Nature 442, 766 (2006). [0pt] [4] F. H. L. Koppens et al., Phys. Rev. Lett. 100, 236802 (2008). [0pt] [5] J. Danon and Yu. V. Nazarov, private communication.

  8. Observation of nuclear reactors on satellites with a balloon-borne gamma-ray telescope

    NASA Technical Reports Server (NTRS)

    O'Neill, Terrence J.; Kerrick, Alan D.; Ait-Ouamer, Farid; Tumer, O. Tumay; Zych, Allen D.

    1989-01-01

    Four Soviet nuclear-powered satellites flying over a double Compton gamma-ray telescope resulted in the detection of gamma rays with 0.3-8.0 MeV energies on April 15, 1988, as the balloonborne telescope searched, from a 35-km altitude, for celestial gamma-ray sources. The satellites included Cosmos 1900 and 1932. The USSR is the only nation currently employing moderated nuclear reactors for satellite power; reactors in space may cause significant problems for gamma-ray astronomy by increasing backgrounds, especially in the case of gamma-ray bursts.

  9. Development of the NPL gamma-ray spectrometer NANA for traceable nuclear decay and structure studies.

    PubMed

    Lorusso, G; Shearman, R; Regan, P H; Judge, S M; Bell, S; Collins, S M; Larijani, C; Ivanov, P; Jerome, S M; Keightley, J D; Lalkovski, S; Pearce, A K; Podolyak, Zs

    2016-03-01

    We present a brief report on the progress towards the construction of the National Nuclear Array (NANA), a gamma-ray coincidence spectrometer for discrete-line nuclear structure and decay measurements. The proposed spectrometer will combine a gamma-ray energy resolution of approximately 3% at 1MeV with sub-nanosecond timing discrimination between successive gamma rays in mutually coincident decay cascades. We also review a number of recent measurements using coincidence fast-timing gamma-ray spectroscopy for nuclear structure studies, which have helped to inform the design criteria for the NANA spectrometer. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Direct capture in nuclear astrophysics: The cases of Oxygen-17(p,gamma)Fluorine-18 and Helium-3(alpha,gamma)Beryllium-7

    NASA Astrophysics Data System (ADS)

    Kontos, Antonios

    Direct radiative capture is a non-resonant one-step nuclear reaction mechanism that in principle does not involve the formation of a compound nucleus. In the absence of strong resonance inside the Gamow window, direct capture can be the dominant contribution to astrophysically important reaction rates. The present thesis studies two such reactions, 17O(p,gamma) 18F and 3He(alpha,gamma)7Be. 17O(p,gamma)18F influences hydrogen-burning nucleosynthesis in several stellar sites, such as red giants, asymptotic giant branch (AGB) stars, massive stars and classical novae. In the relevant temperature range for these environments (T9 = 0.01- 0.4), the main contributions to the rate of this reaction are the direct capture process, two low lying narrow resonances (ElabR = 70 and 193 keV) and the low energy tails of two broad resonances (ElabR = 587 and 714 keV). Previous measurements and calculations give contradictory results for the direct capture contribution which in turn increases the uncertainty of the reaction rate. In addition, very few published cross section data exist for the high energy region that might affect the interpretation of the direct capture and the broad resonances contributions in the lower energy range. In this work we present a measurement of the reaction at a wide proton energy range (Elab = 360 - 1625 keV) and at several angles (θ lab = 0°, 45°, 90°, 135°). 3He(alpha,gamma)7Be is important for the neutrino production in the sun's core and the production of 7Li during the big bang nucleosynthesis. Due to the low level density of 7Be, the reaction mechanism is almost entirely non-resonant at the relevant energies. Recent experiments have improved the uncertainty of the reaction but some discrepancies still exist. In the present work, a relatively wide energy window was measured, ECM = 0.300 -- 1.450 MeV, by detecting the prompt gamma-rays from the reaction. The use of a compact helium jet gas target ensured high gamma-ray detection efficiency

  11. Neutron resonance analysis for nuclear safeguards and security applications

    NASA Astrophysics Data System (ADS)

    Paradela, Carlos; Heyse, Jan; Kopecky, Stefan; Schillebeeckx, Peter; Harada, Hideo; Kitatani, Fumito; Koizumi, Mitsuo; Tsuchiya, Harufumi

    2017-09-01

    Neutron-induced reactions can be used to study the properties of nuclear materials of interest in the fields of nuclear safeguards and security. The elemental and isotopic composition of these materials can be determined by using the presence of resonance structures. This idea is the basis of two non-destructive analysis techniques which have been developed at the GELINA neutron time-of-flight facility at JRC-Geel: Neutron Resonance Capture Analysis (NRCA) and Neutron Resonance Transmission Analysis (NRTA). A combination of NRTA and NRCA has been proposed for the characterisation of particle-like debris of melted fuel formed in severe nuclear accidents. In this work, we present a quantitative validation of the NRTA technique which was used to determine the areal densities of Pu enriched reference samples used for safeguards applications. Less than 2% bias has been obtained for the fissile isotopes, with well-known total cross sections.

  12. Gamma-Ray Transitions Induced in Nuclear Spin Isomers by X-Rays

    NASA Astrophysics Data System (ADS)

    Collins, C. B.; Rusu, A. C.; Zoita, N. C.; Iosif, M. C.; Camase, D. T.; Davanloo, F.; Ur, C. A.; Popescu, I. I.; Pouvesle, J. M.; Dussart, R.; Kirischuk, V. I.; Strilchuk, N. V.; Agee, F. J.

    2001-07-01

    Because of the high density of energy storage and the large cross section for its release, nuclear spin isomers have attracted considerable recent interest. The triggering of induced gamma emission from them has encouraged efforts to develop intense sources of short-wavelength radiation. One of the more interesting examples is the 16+ 4-qp isomer of 178Hf which stores 2.445 MeV for a half-life of 31 years meaning that as a material, such isomeric 178Hf would store 1.3 GJ/g. Recently, a sample containing 6.3×1014 nuclei of the isomer of 178Hf was irradiated with X-ray pulses derived from a device operated at 15 mA to produce bremsstrahlung radiation with end point energies set to values between 60 and 90 keV. Emission of gamma radiation from the sample was increased by 1 2% above the quiescent value of spontaneous emission. Such an accelerated decay of the 178Hf isomer is consistent with an integrated cross section of 2.2×10-22 cm2 keV if the resonant absorption of the X-rays takes place below 20 keV as indicated by the use of selective absorbing filters in the irradiating beam. The work reported here describes the current experimental focus and results recently obtained with the use of coincident detection of emitted gamma photons by several detectors.

  13. Active Detection and Imaging of Nuclear Materials with High-Brightness Gamma Rays

    SciTech Connect

    Barty, C J; Gibson, D J; Albert, F; Anderson, S G; Anderson, G G; Betts, S M; Berry, R D; Fisher, S E; Hagmann, C A; Johnson, M S; Messerly, M J; Phan, H H; Semenov, V A; Shverdin, M Y; Tremaine, A M; Hartemann, F V; Siders, C W; McNabb, D P

    2009-02-26

    A Compton scattering {gamma}-ray source, capable of producing photons with energies ranging from 0.1 MeV to 0.9 MeV has been commissioned and characterized, and then used to perform nuclear resonance fluorescence (NRF) experiments. The performances of the two laser systems (one for electron production, one for scattering), the electron photoinjector, and the linear accelerator are also detailed, and {gamma}-ray results are presented. The key source parameters are the size (0.01 mm{sup 2}), horizontal and vertical divergence (6 x 10 mrad{sup 2}), duration (10 ps), spectrum and intensity (10{sup 5} photons/shot). These parameters are summarized by the peak brightness, 1.5 x 10{sup 15} photons/mm{sup 2}/mrad{sup 2}/s/0.1% bandwidth, measured at 478 keV. Additional measurements of the flux as a function of the timing difference between the drive laser pulse and the relativistic photo-electron bunch, {gamma}-ray beam profile, and background evaluations are presented. These results are systematically compared to theoretical models and computer simulations. NRF measurements performed on {sup 7}Li in LiH demonstrate the potential of Compton scattering photon sources to accurately detect isotopes in situ.

  14. Pump and amplification dynamics of gamma rays in a nuclear medium with the hidden population inversion

    SciTech Connect

    Rivlin, Lev A

    2009-12-31

    The features of the pump dynamics of isomeric nuclei excited by X-rays of a repetitively pulsed relativistic electron beam followed by the production of a medium with the negative absorption of gamma quanta are analysed. In the extended nuclear medium, the pump excites a travelling hidden-population-inversion wave with the anisotropic gamma amplification, which becomes positive in the case of the excess over the critical pump parameter equal to the product of the peak spectral power density of the X-ray source and the relative duration of an ultrashort relativistic electron bunch. In the alternative scheme with orthogonal directions of pumping X-rays and a flux of amplified gamma quanta, the absence of the amplification anisotropy opens up the possibility for constructing a standard two-mirror resonator with Bragg single-crystal reflectors. The critical peak value of the spectral pump power density is compared with the known characteristics of relativistic-electron X-ray sources by examples of some nuclides. (active media)

  15. Multivariate analysis of gamma spectra to characterize used nuclear fuel

    DOE PAGES

    Coble, Jamie; Orton, Christopher; Schwantes, Jon

    2017-01-17

    The Multi-Isotope Process (MIP) Monitor provides an efficient means to monitor the process conditions in used nuclear fuel reprocessing facilities to support process verification and validation. The MIP Monitor applies multivariate analysis to gamma spectroscopy of key stages in the reprocessing stream in order to detect small changes in the gamma spectrum, which may indicate changes in process conditions. This research extends the MIP Monitor by characterizing a used fuel sample after initial dissolution according to the type of reactor of origin (pressurized or boiling water reactor; PWR and BWR, respectively), initial enrichment, burn up, and cooling time. Simulated gammamore » spectra were used in this paper to develop and test three fuel characterization algorithms. The classification and estimation models employed are based on the partial least squares regression (PLS) algorithm. A PLS discriminate analysis model was developed which perfectly classified reactor type for the three PWR and three BWR reactor designs studied. Locally weighted PLS models were fitted on-the-fly to estimate the remaining fuel characteristics. For the simulated gamma spectra considered, burn up was predicted with 0.1% root mean squared percent error (RMSPE) and both cooling time and initial enrichment with approximately 2% RMSPE. Finally, this approach to automated fuel characterization can be used to independently verify operator declarations of used fuel characteristics and to inform the MIP Monitor anomaly detection routines at later stages of the fuel reprocessing stream to improve sensitivity to changes in operational parameters that may indicate issues with operational control or malicious activities.« less

  16. Delayed Gamma Measurements in Different Nuclear Research Reactors Bringing Out the Importance of the Delayed Contribution in Gamma Flux Calculations

    SciTech Connect

    Fourmentel, D.; Radulovic, V.; Barbot, L.; Villard, J-F.; Zerovnik, G.; Snoj, L.; Tarchalski, M.; Pytel, K.; Malouch, F.

    2015-07-01

    Neutron and gamma flux levels are key parameters in nuclear research reactors. In Material Testing Reactors, such as the future Jules Horowitz Reactor, under construction at the French Alternative Energies and Atomic Energy Commission (CEA Cadarache, France), the expected gamma flux levels are very high (nuclear heating is of the order of 20 W/g at 100 MWth). As gamma rays deposit their energy in the reactor structures and structural materials it is important to take them into account when designing irradiation devices. There are only a few sensors which allow measurements of the nuclear heating ; a recent development at the CEA Cadarache allows measurements of the gamma flux using a miniature ionization chamber (MIC). The measured MIC response is often compared with calculation using modern Monte Carlo (MC) neutron and photon transport codes, such as TRIPOLI-4 and MCNP6. In these calculations only the production of prompt gamma rays in the reactor is usually modelled thus neglecting the delayed gamma rays. Hence calculations and measurements are usually in better accordance for the neutron flux than for the gamma flux. In this paper we study the contribution of delayed gamma rays to the total MIC signal in order to estimate the systematic error in gamma flux MC calculations. In order to experimentally determine the delayed gamma flux contributions to the MIC response, we performed gamma flux measurements with CEA developed MIC at three different research reactors: the OSIRIS reactor (MTR - 70 MWth at CEA Saclay, France), the TRIGA MARK II reactor (TRIGA - 250 kWth at the Jozef Stefan Institute, Slovenia) and the MARIA reactor (MTR - 30 MWth at the National Center for Nuclear Research, Poland). In order to experimentally assess the delayed gamma flux contribution to the total gamma flux, several reactor shut down (scram) experiments were performed specifically for the purpose of the measurements. Results show that on average about 30 % of the MIC signal is due to

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

    PubMed

    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.

  18. Emission of nuclear quadrupole resonance from polycrystalline hexamethylenetetramine.

    PubMed

    Ota, G; Itozaki, H

    2008-03-01

    The angular dependence of the nuclear quadrupole resonance (NQR) signal intensity emitted from polycrystalline hexamethylenetetramine has been analytically investigated for all directions for non-contact detection of chemicals by nuclear quadrupole resonance. The field pattern of the NQR signal from a column sample was measured. The emitted patterns were the same as that from a united single magnetic dipole, which fitted well to the estimation based on quadrupole principle axis system. This result is helpful to design an antenna for NQR remote detection.

  19. A triple resonance hyperfine sublevel correlation experiment for assignment of electron-nuclear double resonance lines

    NASA Astrophysics Data System (ADS)

    Potapov, Alexey; Epel, Boris; Goldfarb, Daniella

    2008-02-01

    A new, triple resonance, pulse electron paramagnetic resonance (EPR) sequence is described. It provides spin links between forbidden electron spin transitions (ΔMS=±1, ΔMI≠0) and allowed nuclear spin transitions (ΔMI=±1), thus, facilitating the assignment of nuclear frequencies to their respective electron spin manifolds and paramagnetic centers. It also yields the relative signs of the hyperfine couplings of the different nuclei. The technique is based on the combination of electron-nuclear double resonance (ENDOR) and electron-electron double resonance (ELDOR)-detected NMR experiments in a way similar to the TRIPLE experiment. The feasibility and the information content of the method are demonstrated first on a single crystal of Cu-doped L-histidine and then on a frozen solution of a Cu-histidine complex.

  20. Nuclear Resonance Fluorescence and Isotopic Mapping of Containers

    SciTech Connect

    Johnson, M S; McNabb, D P

    2008-08-08

    National security programs have expressed interest in developing systems to isotopically map shipping containers, fuel assemblies, and waste barrels for various materials including special nuclear material (SNM). Current radiographic systems offer little more than an ambiguous density silhouette of a container's contents. In this paper we will present a system being developed at LLNL to isotopically map containers using the nuclear resonance fluorescence (NRF) method. Recent experimental measurements on NRF strengths in SNM are discussed.

  1. Semiconductor gamma-ray detectors for nuclear medicine

    NASA Astrophysics Data System (ADS)

    Eskin, Joshua Daniel

    Semiconductor-based gamma-ray-imaging detectors are under development for use in high-resolution nuclear medicine imaging applications. These detectors, based on cadmium zinc telluride, hold great promise for delivering improved spatial resolution and detection efficiency over current methods. This dissertation presents work done on three fronts, all directed toward enhancing the practicality of these imaging devices. Electronic readout systems were built to produce gamma-ray images from the raw signals generated by the imagers. Mathematical models were developed to describe the detection process in detail. Finally, a method was developed for recovering the energy spectrum of the original source by using maximum-likelihood estimation techniques. Two electronics systems were built to read out signals from the imaging detectors. The first system takes signals from a 48 x 48-pixel array at 500 k samples per second. Pulse-height histograms are formed for each pixel in the detector, all in real time. A second system was built to read out four 64 x 64 arrays at 4 million pixels per second. This system is based on digital signal processors and flexible software, making it easily adaptable to new imaging tasks. A mathematical model of the detection process was developed as a tool for evaluating possible detector designs. One part of the model describes how the mobile charge carriers, which are released when a gamma ray is absorbed in a photoelectric interaction, induce signals in a readout circuit. Induced signals follow a 'near- field effect,' wherein only carriers moving close to a pixel electrode produce significant signal. Detector pixels having lateral dimensions that are small compared to the detector thickness will develop a signal primarily due to a single carrier type. This effect is confirmed experimentally in time-resolved measurements and with pulse-height spectra. The second part of the model is a simulation of scattering processes that take place when a gamma

  2. Nuclear dynamics during the resonant Auger decay of water molecules.

    PubMed

    Eroms, Matthis; Vendrell, Oriol; Jungen, Martin; Meyer, Hans-Dieter; Cederbaum, Lorenz S

    2009-04-21

    The resonant Auger decay of water molecules is investigated. Here, the excitation process, the motion of the nuclei, and the decay of the resonantly excited state take place on the same (femtosecond) time scale. Therefore, a multistep picture is not suitable. Instead, the nuclear wave packet at each instant of time is a result of several competing and interfering contributions. The resonant Auger decay of water is simulated and its dynamics is studied in detail. An analysis of the final vibrational distribution is given. The multiconfiguration time-dependent Hartree method is used to study the intricate multidimensional dynamics. The potential energy surfaces have been calculated using a multireference configuration interaction method.

  3. Low-frequency nuclear magnetic resonance and nuclear quadrupole resonance spectrometer based on a dc superconducting quantum interference device

    SciTech Connect

    Fan, N.Q.; Clarke, J. )

    1991-06-01

    A sensitive spectrometer, based on a dc superconducting quantum interference device, for the direct detection of low-frequency pulsed nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR), is described. The frequency response extends from about 10 to 200 kHz, and the recovery time after the magnetic pulse is removed is typically 50 {mu}s. As examples, NMR spectra are shown from Pt and Cu metal powders in a magnetic field of 6 mT, and NQR spectra are shown from {sup 2}D in a tunneling methyl group and {sup 14}N in NH{sub 4}ClO{sub 4}.

  4. Nuclear magnetic resonance study of potassium dihydrophosphate

    NASA Astrophysics Data System (ADS)

    Uskova, N. I.; Podorozhkin, D. Yu.; Charnaya, E. V.; Nefedov, D. Yu.; Baryshnikov, S. V.; Bugaev, A. S.; Lee, M. K.; Chang, L. J.

    2016-04-01

    A powder sample of potassium dihydrophosphate KH2PO4 has been studied by the 31P NMR method in a wide temperature range covering the ferroelectric phase transition. Changes in the position and shape of the resonance line at the transition to the ferroelectric phase have been revealed. The parameters of the chemical shift tensor of 31P (isotropic shift, anisotropy, and asymmetry) in the ferroelectric phase have been calculated from the experimental data. A sharp increase in the anisotropy of the tensor at the phase transition has been demonstrated. Dielectric measurements have also been carried out to verify the transition temperature.

  5. Capacitor-based detection of nuclear magnetization: nuclear quadrupole resonance of surfaces.

    PubMed

    Gregorovič, Alan; Apih, Tomaž; Kvasić, Ivan; Lužnik, Janko; Pirnat, Janez; Trontelj, Zvonko; Strle, Drago; Muševič, Igor

    2011-03-01

    We demonstrate excitation and detection of nuclear magnetization in a nuclear quadrupole resonance (NQR) experiment with a parallel plate capacitor, where the sample is located between the two capacitor plates and not in a coil as usually. While the sensitivity of this capacitor-based detection is found lower compared to an optimal coil-based detection of the same amount of sample, it becomes comparable in the case of very thin samples and even advantageous in the proximity of conducting bodies. This capacitor-based setup may find its application in acquisition of NQR signals from the surface layers on conducting bodies or in a portable tightly integrated nuclear magnetic resonance sensor.

  6. Quantum computing using electron-nuclear double resonances

    NASA Astrophysics Data System (ADS)

    Bowden, Charles M.; Dowling, Jonathan P.; Hotaling, Steven P.

    1997-07-01

    We consider the use of Electron-Nuclear Double Resonance (ENDOR) techniques in quantum computing. ENDOR resolution as a possible limiting factor is discussed. It is found that ENDOR and double-ENDOR techniques have sufficient resolution for quantum computing applications.

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

    ERIC Educational Resources Information Center

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

    2006-01-01

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

  8. High-Resolution Nuclear Magnetic Resonance of Solids.

    ERIC Educational Resources Information Center

    Maciel, Gary E.

    1984-01-01

    Examines recent developments in techniques for obtaining high-resolution nuclear magnetic resonance (NMR) spectra on solid samples, discussing the kinds of applications for which these techniques are well suited. Also discusses the characteristics of NMR of solids and generating magnetization for NMR in solids. (JN)

  9. Concepts in Biochemistry: Nuclear Magnetic Resonance Spectroscopy in Biochemistry.

    ERIC Educational Resources Information Center

    Cheatham, Steve

    1989-01-01

    Discusses the nature of a nuclear magnetic resonance (NMR) experiment, the techniques used, the types of structural and dynamic information obtained, and how one can view and refine structures using computer graphics techniques in combination with NMR data. Provides several spectra and a computer graphics image from B-form DNA. (MVL)

  10. C-13 nuclear magnetic resonance in organic geochemistry.

    NASA Technical Reports Server (NTRS)

    Balogh, B.; Wilson, D. M.; Burlingame, A. L.

    1972-01-01

    Study of C-13 nuclear magnetic resonance (NMR) spectra of polycyclic fused systems. The fingerprint qualities of the natural abundance in C-13 NMR spectra permitting unequivocal identification of these compounds is discussed. The principle of structural additivity of C-13 NMR information is exemplified on alpha and beta androstanes, alpha and beta cholestanes, ergostanes, sitostanes, and isodecanes.

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

    ERIC Educational Resources Information Center

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

    2006-01-01

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

  12. Nuclear Magnetic Resonance Coupling Constants and Electronic Structure in Molecules.

    ERIC Educational Resources Information Center

    Venanzi, Thomas J.

    1982-01-01

    Theory of nuclear magnetic resonance spin-spin coupling constants and nature of the three types of coupling mechanisms contributing to the overall spin-spin coupling constant are reviewed, including carbon-carbon coupling (neither containing a lone pair of electrons) and carbon-nitrogen coupling (one containing a lone pair of electrons).…

  13. High-Resolution Nuclear Magnetic Resonance of Solids.

    ERIC Educational Resources Information Center

    Maciel, Gary E.

    1984-01-01

    Examines recent developments in techniques for obtaining high-resolution nuclear magnetic resonance (NMR) spectra on solid samples, discussing the kinds of applications for which these techniques are well suited. Also discusses the characteristics of NMR of solids and generating magnetization for NMR in solids. (JN)

  14. Nuclear Magnetic Resonance Coupling Constants and Electronic Structure in Molecules.

    ERIC Educational Resources Information Center

    Venanzi, Thomas J.

    1982-01-01

    Theory of nuclear magnetic resonance spin-spin coupling constants and nature of the three types of coupling mechanisms contributing to the overall spin-spin coupling constant are reviewed, including carbon-carbon coupling (neither containing a lone pair of electrons) and carbon-nitrogen coupling (one containing a lone pair of electrons).…

  15. Concepts in Biochemistry: Nuclear Magnetic Resonance Spectroscopy in Biochemistry.

    ERIC Educational Resources Information Center

    Cheatham, Steve

    1989-01-01

    Discusses the nature of a nuclear magnetic resonance (NMR) experiment, the techniques used, the types of structural and dynamic information obtained, and how one can view and refine structures using computer graphics techniques in combination with NMR data. Provides several spectra and a computer graphics image from B-form DNA. (MVL)

  16. Probing vibrational anisotropy with nuclear resonance vibrational spectroscopy.

    SciTech Connect

    Pavlik, J. W.; Barabanschikov, A.; Oliver, A. G.; Alp, E. E.; Sturhahn, W.; Zhao, J.; Sage, J. T.; Scheidt, W. R.

    2010-06-14

    A NRVS single-crystal study (NRVS=nuclear resonance vibrational spectroscopy) has provided detailed information on the in-plane modes of nitrosyl iron porphyrinate [Fe(oep)(NO)] (see picture; oep=octaethylporphyrin). The axial nitrosyl ligand controls the direction of the in-plane iron motion.

  17. Nuclear resonant scattering beamline at the Advanced Photon Source

    SciTech Connect

    Alp, E.E.; Mooney, T.M.; Toellner, T.; Sturhahn, W.

    1993-09-01

    The principal and engineering aspects of a dedicated synchrotron radiation beamline under construction at the Advanced Photon Source for nuclear resonant scattering purposes are explained. The expected performance in terms of isotopes to be studied, flux, and timing properties is discussed.

  18. Nuclear magnetic resonance and nuclear spin relaxation in AlAs quantum well probed by ESR

    NASA Astrophysics Data System (ADS)

    Shchepetilnikov, A. V.; Frolov, D. D.; Nefyodov, Yu. A.; Kukushkin, I. V.; Smirnov, D. S.; Tiemann, L.; Reichl, C.; Dietsche, W.; Wegscheider, W.

    2016-12-01

    The study of nuclear magnetic resonance and nuclear spin-lattice relaxation was conducted in an asymmetrically doped to n ˜1.8 ×1011cm-2 16 nm AlAs quantum well grown in the [001 ] direction. The dynamic polarization of nuclear spins due to a hyperfine interaction resulted in the so-called Overhauser shift of two-dimensional conduction electron spin resonance. The maximum shifts achieved in the experiments are several orders of magnitude smaller than in GaAs-based heterostructures, indicating that the hyperfine interaction is weak. The nuclear spin-lattice relaxation time extracted from the decay of the Overhauser shift over time turned out to depend on the filling factor of the two-dimensional electron system. This observation indicates that nuclear spin-lattice relaxation is mostly due to the interaction between electron and nuclear spins. The Overhauser shift diminishes resonantly when the rf radiation of certain frequencies was applied to the sample. This effect served as an indirect, yet powerful, method for nuclear magnetic resonance detection: NMR quadrupole splitting of 75As nuclei was clearly resolved. Theoretical calculations performed describe well these experimental findings.

  19. Stroboscopic detection of nuclear resonance in an arbitrary scattering channel.

    PubMed

    Deák, L; Bottyán, L; Callens, R; Coussement, R; Major, M; Nasu, S; Serdons, I; Spiering, H; Yoda, Y

    2015-03-01

    The theory of heterodyne/stroboscopic detection of nuclear resonance scattering is developed, starting from the total scattering matrix as a product of the matrix of the reference sample and the sample under study. This general approach holds for all dynamical scattering channels. In the forward channel, which has been discussed in detail in the literature, the electronic scattering manifests itself only in an energy-independent diminution of the scattered intensity. In all other channels, complex resonance line shapes of the heterodyne/stroboscopic spectra are encountered, as a result of the interference of electronic and nuclear scattering. The grazing-incidence case will be evaluated and described in detail. Experimental data of classical X-ray reflectivity and their stroboscopically detected resonant counterpart spectra on the [(nat)Fe/(57)Fe]10 isotope periodic multilayer and antiferromagnetic [(57)Fe/Cr]20 superlattice are fitted simultaneously.

  20. Nuclear quadrupole resonance detection of explosives: an overview

    NASA Astrophysics Data System (ADS)

    Miller, Joel B.

    2011-06-01

    Nuclear Quadrupole Resonance (NQR) is a spectroscopic technique closely related to Nuclear Magnetic Resonance (NMR) and Magnetic Resonance Imaging (MRI). These techniques, and NQR in particular, induce signals from the material being interrogated that are very specific to the chemical and physical structure of the material, but are relatively insensitive to the physical form of the material. NQR explosives detection exploits this specificity to detect explosive materials, in contrast to other well known techniques that are designed to detect explosive devices. The past two decades have seen a large research and development effort in NQR explosives detection in the United States aimed at transportation security and military applications. Here, I will briefly describe the physical basis for NQR before discussing NQR developments over the past decade, with particular emphasis on landmine detection and the use of NQR in combating IED's. Potential future directions for NQR research and development are discussed.

  1. In vivo nuclear magnetic resonance imaging

    NASA Technical Reports Server (NTRS)

    Leblanc, A.

    1986-01-01

    During the past year the Woodlands Baylor Magnetic Resonance Imaging (MRI) facility became fully operational. A detailed description of this facility is given. One significant instrument addition this year was the 100 MHz, 40cm bore superconducting imaging spectrometer. This instrument gives researchers the capability to acquire high energy phosphate spectra. This will be used to investigate ATP, phosphocreatinine and inorganic phosphate changes in normal and atrophied muscle before, during and after exercise. An exercise device for use within the bore of the imaging magnet is under design/construction. The results of a study of T sub 1 and T sub 2 changes in atrophied muscle in animals and human subjects are given. The imaging and analysis of the lower leg of 15 research subjects before and after 5 weeks of complete bedrest was completed. A compilation of these results are attached.

  2. In vivo nuclear magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Leblanc, A.

    1986-05-01

    During the past year the Woodlands Baylor Magnetic Resonance Imaging (MRI) facility became fully operational. A detailed description of this facility is given. One significant instrument addition this year was the 100 MHz, 40cm bore superconducting imaging spectrometer. This instrument gives researchers the capability to acquire high energy phosphate spectra. This will be used to investigate ATP, phosphocreatinine and inorganic phosphate changes in normal and atrophied muscle before, during and after exercise. An exercise device for use within the bore of the imaging magnet is under design/construction. The results of a study of T sub 1 and T sub 2 changes in atrophied muscle in animals and human subjects are given. The imaging and analysis of the lower leg of 15 research subjects before and after 5 weeks of complete bedrest was completed. A compilation of these results are attached.

  3. Change in the observed half-life of an excited nuclear state under conditions of a resonance environment

    SciTech Connect

    Loginov, Yu. E.

    2010-01-15

    A model description of the increase in the observed value of the half-life of isomeric nuclei {sup 119m1}Sn (E = 23.8 keV, T{sub 1/2} {approx} 18 ns) in a resonance environment created by stable nuclei of {sup 119}Sn is proposed. According to the model used, the observed effect is due to gamma radiation from isomeric nuclei {sup 119m1}Sn newly produced upon the resonance capture of gamma rays emitted in {sup 119m1}Sn decay by stable nuclei of {sup 119}Sn. On the basis of T{sub 1/2} values that were measured previously, the radiative shift of the position of an excited nuclear state (nuclear analog of the Lamb shift in an atom), {Delta}{omega}{sub 0}, was estimated at 1.5(2) x 10{sup 11} s{sup -1} for the isomer {sup 119m1}Sn.

  4. First results from ASP on resonance production in. gamma gamma. interactions

    SciTech Connect

    Roe, N.

    1988-05-01

    The reaction e/sup +/e/sup -//yields/e/sup +/e/sup -//gamma/sup *//gamma/sup *///yields/(e/sup +/e/sup -/)/eta/, with subsequent decay of the /eta/ into two photons, has been observed with the ASP detector at the PEP e/sup +/e/sup -/ storage ring at /radical/ s=29 GeV. A measurement of the radiative width of the /eta/ yields the preliminary result /Gamma/(/eta//yields//gamma//gamma/) = .489 /+-/ .009 /+-/ .055 keV. Evidence for the production of the /eta/' with decay into two photons has also been observed.

  5. Experimental Study of Level Density and {gamma}-strength Functions from Compound Nuclear Reactions

    SciTech Connect

    Voinov, A. V.; Grimes, S. M.; Brune, C. R.; Massey, T. N.; Schiller, A.; Guttormsen, M.; Siem, S.

    2008-04-17

    The current status of experimental study of level density and {gamma}-strength functions is reviewed. Three experimental techniques are used. These are measurements of particle evaporation spectra from compound nuclear reactions, the measurements of particle-{gamma} coincidences from inelastic scattering and pick-up reactions and the method of two-step {gamma}-cascades following neutron/proton radiative capture. Recent experimental data on level densities from neutron evaporation spectra are shown. The first results on the cascade {gamma}-spectrum from the {sup 59}Co(p,2{gamma}){sup 60}Ni reaction are presented.

  6. Nuclear magnetic resonance imaging with 90-nm resolution.

    PubMed

    Mamin, H J; Poggio, M; Degen, C L; Rugar, D

    2007-05-01

    Magnetic resonance imaging (MRI) is a powerful imaging technique that typically operates on the scale of millimetres to micrometres. Conventional MRI is based on the manipulation of nuclear spins with radio-frequency fields, and the subsequent detection of spins with induction-based techniques. An alternative approach, magnetic resonance force microscopy (MRFM), uses force detection to overcome the sensitivity limitations of conventional MRI. Here, we show that the two-dimensional imaging of nuclear spins can be extended to a spatial resolution better than 100 nm using MRFM. The imaging of 19F nuclei in a patterned CaF(2) test object was enabled by a detection sensitivity of roughly 1,200 nuclear spins at a temperature of 600 mK. To achieve this sensitivity, we developed high-moment magnetic tips that produced field gradients up to 1.4 x 10(6) T m(-1), and implemented a measurement protocol based on force-gradient detection of naturally occurring spin fluctuations. The resulting detection volume was less than 650 zeptolitres. This is 60,000 times smaller than the previous smallest volume for nuclear magnetic resonance microscopy, and demonstrates the feasibility of pushing MRI into the nanoscale regime.

  7. Moessbauer medium with a hidden nuclear population inversion and negative absorption of gamma quanta

    SciTech Connect

    Rivlin, Lev A

    2011-06-30

    We consider physical foundations of an eventual experiment aimed at observing stimulated gamma-photon emission of long-lived Moessbauer isomers through selective frequency modulation of gamma-resonances establishing hidden population inversion without exceeding the number of excited nuclei over unexcited ones and without additional pumping. The examples of suitable nuclei and numerical estimates of the parameters are presented. (active media)

  8. Nondestructive Inspection System for Special Nuclear Material Using Inertial Electrostatic Confinement Fusion Neutrons and Laser Compton Scattering Gamma-Rays

    NASA Astrophysics Data System (ADS)

    Ohgaki, H.; Daito, I.; Zen, H.; Kii, T.; Masuda, K.; Misawa, T.; Hajima, R.; Hayakawa, T.; Shizuma, T.; Kando, M.; Fujimoto, S.

    2017-07-01

    A Neutron/Gamma-ray combined inspection system for hidden special nuclear materials (SNMs) in cargo containers has been developed under a program of Japan Science and Technology Agency in Japan. This inspection system consists of an active neutron-detection system for fast screening and a laser Compton backscattering gamma-ray source in coupling with nuclear resonance fluorescence (NRF) method for precise inspection. The inertial electrostatic confinement fusion device has been adopted as a neutron source and two neutron-detection methods, delayed neutron noise analysis method and high-energy neutron-detection method, have been developed to realize the fast screening system. The prototype system has been constructed and tested in the Reactor Research Institute, Kyoto University. For the generation of the laser Compton backscattering gamma-ray beam, a race track microtron accelerator has been used to reduce the size of the system. For the NRF measurement, an array of LaBr3(Ce) scintillation detectors has been adopted to realize a low-cost detection system. The prototype of the gamma-ray system has been demonstrated in the Kansai Photon Science Institute, National Institutes for Quantum and Radiological Science and Technology. By using numerical simulations based on the data taken from these prototype systems and the inspection-flow, the system designed by this program can detect 1 kg of highly enriched 235U (HEU) hidden in an empty 20-ft container within several minutes.

  9. Experimental nuclear level densities and {gamma}-ray strength functions in Sc and V isotopes

    SciTech Connect

    Larsen, A. C.; Guttormsen, M.; Ingebretsen, F.; Messelt, S.; Rekstad, J.; Siem, S.; Syed, N. U. H.; Chankova, R.; Loennroth, T.; Schiller, A.; Voinov, A.

    2008-04-17

    The nuclear physics group at the Oslo Cyclotron Laboratory has developed a method to extract nuclear level density and {gamma}-ray strength function from first-generation {gamma}-ray spectra. This method is applied on the nuclei {sup 44,45}Sc and {sup 50,51}V in this work. The experimental level densities of {sup 44,45}Sc are compared to calculated level densities using a microscopic model based on BCS quasiparticles within the Nilsson level scheme. The {gamma}-ray strength functions are also compared to theoretical expectations, showing an unexpected enhancement of the {gamma}-ray strength for low {gamma} energies (E{sub {gamma}}{<=}3 MeV) in all the isotopes studied here. The physical origin of this enhancement is not yet understood.

  10. Gamma ray sources based on resonant backscattering of laser beams with relativistic heavy ion beams

    SciTech Connect

    Bessonov, E.G.; Kim, Kwang-Je

    1995-04-01

    Resonant backscattering of high-power laser beam with non-fully stripped, ultra-relativistic ion beams in storage rings is studied as a source for {gamma}-ray beams for elementary particle physics experiments. The laser frequency is chosen to be resonant with one of the transition frequencies of the moving ions, and the bandwidth is chosen to cover the full Doppler broadening of the ions in the beam. Due to the resonance, the scattering cross section is enhanced by a large factor compared to the Thomson cross section, of the order 10{sup 8} for some examples considered here. The performance of the LHC as a possible {gamma}-generator or a {gamma} {minus} {gamma} collider is estimated. We study the case where hydrogen-like Pb ions with 2.8 TeV per nucleon are scattered by a train of 1100 {Angstrom}, 20 mg laser pulses with the same pulse time format as the ion beam. A free electron laser can be designed satisfying the requirements. It is estimated that {gamma}-rays of maximum quantum energy of 0.4 give at an average rate of 0.67 10{sup 18} are generated in this scheme. The luminosity of the corresponding {gamma} {minus} {gamma} collider will be about 0.9 10{sup 33} cm{sup {minus}2}s{sup {minus}1}.

  11. Simulation of nuclear quadrupole resonance for sensor probe optimization.

    PubMed

    Shinohara, Junichiro; Sato-Akaba, Hideo; Itozaki, Hideo

    2012-01-01

    A simulation method to estimate the detection efficiency of nuclear quadrupole resonance (NQR) was proposed for optimizing a sensing probe operating at radio frequencies (RFs). It first calculates the transmitted magnetic field from the probe coil to the target sample. The nuclei make quadrupole resonance by it. We considered this nonlinear reaction to estimate NQR emission by the nuclei. Then the received NQR signal intensity from the sample at the probe coil. We calculated the efficiency by testing two different probe types (solenoid and gradiometer) and by changing the relative positions of the probe and sample. The simulation results were in good agreement with the experimental results.

  12. Algorithmic cooling in liquid-state nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    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.

  13. Detection and estimation of magnetization induced resonances in unilateral nuclear magnetic resonance (NMR) sensors

    NASA Astrophysics Data System (ADS)

    Prabhu Gaunkar, N.; Bulu, I.; Song, Y. Q.; Mina, M.; Jiles, D. C.

    2017-05-01

    In this work a systematic identification of factors contributing to signal ringing in unilateral nuclear magnetic resonance (NMR) sensors is conducted. Resonant peaks that originate due to multiple factors such as NMR, electrical, magneto-acoustic, core material response, eddy currents and other factors were observed. The peaks caused by the measurement system or electrical resonances and induced magnet vibrations are further analyzed. They appear in every measurement and are considered as interference to signals received from the magnetic core. Forming a distinction between different peaks is essential in identifying the primary contribution to the captured resonant signal. The measurements for the magnetic core indicate that the magnetization induced resonant peaks of the core have relatively higher amplitudes and shorter decay times at low frequencies.

  14. DC superconducting quantum interference device usable in nuclear quadrupole resonance and zero field nuclear magnetic spectrometers

    DOEpatents

    Fan, Non Q.; Clarke, John

    1993-01-01

    A spectrometer for measuring the nuclear quadrupole resonance spectra or the zero-field nuclear magnetic resonance spectra generated by a sample is disclosed. The spectrometer uses an amplifier having a dc SQUID operating in a flux-locked loop for generating an amplified output as a function of the intensity of the signal generated by the sample. The flux-locked loop circuit includes an integrator. The amplifier also includes means for preventing the integrator from being driven into saturation. As a result, the time for the flux-locked loop to recover from the excitation pulses generated by the spectrometer is reduced.

  15. DC superconducting quantum interference device usable in nuclear quadrupole resonance and zero field nuclear magnetic spectrometers

    DOEpatents

    Fan, N.Q.; Clarke, J.

    1993-10-19

    A spectrometer for measuring the nuclear quadrupole resonance spectra or the zero-field nuclear magnetic resonance spectra generated by a sample is disclosed. The spectrometer uses an amplifier having a dc SQUID operating in a flux-locked loop for generating an amplified output as a function of the intensity of the signal generated by the sample. The flux-locked loop circuit includes an integrator. The amplifier also includes means for preventing the integrator from being driven into saturation. As a result, the time for the flux-locked loop to recover from the excitation pulses generated by the spectrometer is reduced. 7 figures.

  16. Exact calculations of nuclear-recoil energies from prompt gamma decays resulting from neutron capture

    SciTech Connect

    Kinney, J.H.

    1981-07-20

    The results of an accurate determination of the recoil spectrum from (n, ..gamma..) reactions in molybdenum are presented. The recoil spectrum has been calculated from nuclear level structure data and measured branching ratios. Angular correlations between successive gammas have been accounted for using the standard theoretical techniques of Racah algebra and the density matrix formalism.

  17. The origins and future of nuclear magnetic resonance imaging

    SciTech Connect

    Wehrli, F.W. )

    1992-06-01

    What began as a curiosity of physics has become the preeminent method of diagnostic medical imaging and may displace x-ray-based techniques in the 21st century. During the past two decades nuclear magnetic resonance has revolutionized chemistry, biochemistry, biology and, more recently, diagnostic medicine. Nuclear magnetic resonance imaging, (MRI) as it is commonly called, is fundamentally different from x-ray-based techniques in terms of the principles of spatial encoding and mechanisms of signal and contrast generation involved. MRI has a far richer ultimate potential than any other imaging technique known today, and its technology and applications are still far from maturation, which may not occur until early in the 21st century. 23 refs., 6 figs.

  18. Advanced Quantification of Plutonium Ionization Potential to Support Nuclear Forensic Evaluations by Resonance Ionization Mass Spectrometry

    DTIC Science & Technology

    2015-06-01

    QUANTIFICATION OF PLUTONIUM IONIZATION POTENTIAL TO SUPPORT NUCLEAR FORENSIC EVALUATIONS BY RESONANCE IONIZATION MASS SPECTROMETRY by Craig T...PLUTONIUM IONIZATION POTENTIAL TO SUPPORT NUCLEAR FORENSIC EVALUATIONS BY RESONANCE IONIZATION MASS SPECTROMETRY 5. FUNDING NUMBERS 6. AUTHOR(S...mass spectrometry (RIMS) to problems related to nuclear forensics and, in particular, to the analysis and quantification of the debris from nuclear

  19. Chemometric Analysis of Nuclear Magnetic Resonance Spectroscopy Data

    SciTech Connect

    ALAM,TODD M.; ALAM,M. KATHLEEN

    2000-07-20

    Chemometric analysis of nuclear magnetic resonance (NMR) spectroscopy has increased dramatically in recent years. A variety of different chemometric techniques have been applied to a wide range of problems in food, agricultural, medical, process and industrial systems. This article gives a brief review of chemometric analysis of NMR spectral data, including a summary of the types of mixtures and experiments analyzed with chemometric techniques. Common experimental problems encountered during the chemometric analysis of NMR data are also discussed.

  20. Low-frequency nuclear quadrupole resonance with a dc SQUID

    SciTech Connect

    Chang, J.W.

    1991-07-01

    Conventional pure nuclear quadrupole resonance (NQR) is a technique well suited for the study of very large quadrupolar interactions. Numerous nuclear magnetic resonance (NMR) techniques have been developed for the study of smaller quadrupolar interactions. However, there are many nuclei which have quadrupolar interactions of intermediate strength. Quadrupolar interactions in this region have traditionally been difficult or unfeasible to detect. This work describes the development and application of a SQUID NQR technique which is capable of measuring intermediate strength quadrupolar interactions, in the range of a few hundred kilohertz to several megahertz. In this technique, a dc SQUID (Superconducting QUantum Interference Device) is used to monitor the longitudinal sample magnetization, as opposed to the transverse magnetization, as a rf field is swept in frequency. This allows the detection of low-frequency nuclear quadrupole resonances over a very wide frequency range with high sensitivity. The theory of this NQR technique is discussed and a description of the dc SQUID system is given. In the following chapters, the spectrometer is discussed along with its application to the study of samples containing half-odd-integer spin quadrupolar nuclei, in particular boron-11 and aluminum-27. The feasibility of applying this NQR technique in the study of samples containing integer spin nuclei is discussed in the last chapter. 140 refs., 46 figs., 6 tabs.

  1. Low-frequency nuclear quadrupole resonance with a dc SQUID

    SciTech Connect

    Chang, J.W.

    1991-07-01

    Conventional pure nuclear quadrupole resonance (NQR) is a technique well suited for the study of very large quadrupolar interactions. Numerous nuclear magnetic resonance (NMR) techniques have been developed for the study of smaller quadrupolar interactions. However, there are many nuclei which have quadrupolar interactions of intermediate strength. Quadrupolar interactions in this region have traditionally been difficult or unfeasible to detect. This work describes the development and application of a SQUID NQR technique which is capable of measuring intermediate strength quadrupolar interactions, in the range of a few hundred kilohertz to several megahertz. In this technique, a dc SQUID (Superconducting QUantum Interference Device) is used to monitor the longitudinal sample magnetization, as opposed to the transverse magnetization, as a rf field is swept in frequency. This allows the detection of low-frequency nuclear quadrupole resonances over a very wide frequency range with high sensitivity. The theory of this NQR technique is discussed and a description of the dc SQUID system is given. In the following chapters, the spectrometer is discussed along with its application to the study of samples containing half-odd-integer spin quadrupolar nuclei, in particular boron-11 and aluminum-27. The feasibility of applying this NQR technique in the study of samples containing integer spin nuclei is discussed in the last chapter. 140 refs., 46 figs., 6 tabs.

  2. 73Ge-Nuclear Magnetic Resonance/Nuclear Quadrupole Resonance Investigation of Magnetic Properties of URhGe

    NASA Astrophysics Data System (ADS)

    Kotegawa, Hisashi; Fukumoto, Kenta; Toyama, Toshihiro; Tou, Hideki; Harima, Hisatomo; Harada, Atsushi; Kitaoka, Yoshio; Haga, Yoshinori; Yamamoto, Etsuji; Ōnuki, Yoshichika; Itoh, Kohei M.; Haller, Eugene E.

    2015-05-01

    We report on the 73Ge-nuclear magnetic resonance (NMR)/nuclear quadrupole resonance (NQR) results for the ferromagnetic (FM) superconductor URhGe. The magnitude and direction of the internal field, Hint, and the parameters of the electric field gradient at the Ge site were determined experimentally. By using powdered polycrystalline samples oriented by different methods, the field dependences of NMR shift and nuclear spin relaxation rates for H0 || c (easy axis) and H0 || b were obtained. From the NMR shifts for H0 || b, we confirmed a gradual suppression of the Curie temperature and observed a phase separation near the spin reorientation. The observation of the phase separation gives microscopic evidence that the spin reorientation under H0 || b is of first order at low temperatures. The nuclear spin-lattice relaxation rate 1/T1 indicates that the magnetic fluctuations are suppressed for H0 || c, whereas the fluctuations remain strongly for H0 || b. The enhancements of both 1/T1T and the nuclear spin-spin relaxation rate 1/T2 for H0 || b toward the spin reorientation field suggest that the field-induced superconductivity in URhGe emerges under the magnetic fluctuations along the b- and c-axes.

  3. Synaptic Plasticity Controls Sensory Responses through Frequency-Dependent Gamma Oscillation Resonance

    PubMed Central

    Paik, Se-Bum; Glaser, Donald A.

    2010-01-01

    Synchronized gamma frequency oscillations in neural networks are thought to be important to sensory information processing, and their effects have been intensively studied. Here we describe a mechanism by which the nervous system can readily control gamma oscillation effects, depending selectively on visual stimuli. Using a model neural network simulation, we found that sensory response in the primary visual cortex is significantly modulated by the resonance between “spontaneous” and “stimulus-driven” oscillations. This gamma resonance can be precisely controlled by the synaptic plasticity of thalamocortical connections, and cortical response is regulated differentially according to the resonance condition. The mechanism produces a selective synchronization between the afferent and downstream neural population. Our simulation results explain experimental observations such as stimulus-dependent synchronization between the thalamus and the cortex at different oscillation frequencies. The model generally shows how sensory information can be selectively routed depending on its frequency components. PMID:20838581

  4. Nuclear composition of magnetized gamma-ray burst jets

    NASA Astrophysics Data System (ADS)

    Shibata, Sanshiro; Tominaga, Nozomu

    2015-06-01

    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 the detailed nuclear composition of the jet by post-processing calculation. We found that if the temperature at the jet launch site is above 4.7 × 109 K, quasi-statistical equilibrium is established and heavy nuclei are dissociated into light particles such as 4He 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_j^iso ≲ 3.9 × 10^{50} ( R_i/107 cm)^2(1 + σi) erg s-1, where Ri and σi are the initial radius of the jets and the initial magnetization parameter, respectively. If the jet is initially dominated by radiation field (i.e., σi ≪ 1) and the isotropic luminosity is relatively high (L_j^iso ≳ 4 × 10^{52} erg s-1), the metal nuclei cannot survive in the jet. On the other hand, if the jet is mainly accelerated by magnetic field (i.e., σi ≫ 1), metal nuclei initially contained in the jet can survive without serious dissociation even in the case of a high-luminosity jet. If the jet contains metal nuclei, the dominant nuclei are 28Si, 16O, and 32S and the mean mass number can be ˜ 25.

  5. The ionic mechanism of gamma resonance in rat striatal fast-spiking neurons.

    PubMed

    Sciamanna, Giuseppe; Wilson, Charles J

    2011-12-01

    Striatal fast-spiking (FS) cells in slices fire in the gamma frequency range and in vivo are often phase-locked to gamma oscillations in the field potential. We studied the firing patterns of these cells in slices from rats ages 16-23 days to determine the mechanism of their gamma resonance. The resonance of striatal FS cells was manifested as a minimum frequency for repetitive firing. At rheobase, cells fired a doublet of action potentials or doublets separated by pauses, with an instantaneous firing rate averaging 44 spikes/s. The minimum rate for sustained firing was also responsible for the stuttering firing pattern. Firing rate adapted during each episode of firing, and bursts were terminated when firing was reduced to the minimum sustainable rate. Resonance and stuttering continued after blockade of Kv3 current using tetraethylammonium (0.1-1 mM). Both gamma resonance and stuttering were strongly dependent on Kv1 current. Blockade of Kv1 channels with dendrotoxin-I (100 nM) completely abolished the stuttering firing pattern, greatly lowered the minimum firing rate, abolished gamma-band subthreshold oscillations, and slowed spike frequency adaptation. The loss of resonance could be accounted for by a reduction in potassium current near spike threshold and the emergence of a fixed spike threshold. Inactivation of the Kv1 channel combined with the minimum firing rate could account for the stuttering firing pattern. The resonant properties conferred by this channel were shown to be adequate to account for their phase-locking to gamma-frequency inputs as seen in vivo.

  6. Magnetic-field cycling instrumentation for dynamic nuclear polarization-nuclear magnetic resonance using photoexcited triplets.

    PubMed

    Kagawa, Akinori; Negoro, Makoto; Takeda, Kazuyuki; Kitagawa, Masahiro

    2009-04-01

    To advance static solid-state NMR with hyperpolarized nuclear spins, a system has been developed enabling dynamic nuclear polarization (DNP) using electron spins in the photoexcited triplet state with X-band microwave apparatus, followed by static solid-state nuclear magnetic resonance (NMR) experiments using the polarized nuclear-spin system with a goniometer. In order to perform the DNP and NMR procedures in different magnetic fields, the DNP system and the NMR system are spatially separated, between which the sample can be shuttled while its orientation is controlled in a reproducible fashion. We demonstrate that the system developed in this work is operational for solid-state NMR with hyperpolarized nuclear-spin systems in static organic materials, and also discuss the application of our system.

  7. DC SQUID Spectrometers for Nuclear Quadrupole and Low-Field Nuclear Magnetic Resonance Spectroscopy

    SciTech Connect

    TonThat, Dinh M.

    1998-04-01

    The dc Superconducting Quantum Interference Device (SQUJD) is a very sensitive detector of magnetic flux, with a typical flux noise of the order of 1 μΦ0Hz-1/2 at liquid helium temperature (Φ0=h/2e). This inherent flux sensitivity of the SQUID is used in a spectrometer for the detection of nuclear magnetic resonance (NMR.)and nuclear quadruple resonance (NQR). The processing magnetic field from the nuclear spins is coupled to the SQUID by mean of a flux transformer. The SQUID NMR spectrometer is used to measure the longitudinal relaxation time T1 of solid 129Xe at 4.2 K down to 0.1 mT.

  8. Isotopic imaging via nuclear resonance fluorescence with laser-based Thomson radiation

    DOEpatents

    Barty, Christopher P. J.; Hartemann, Frederic V.; McNabb, Dennis P.; Pruet, Jason A.

    2009-07-21

    The present invention utilizes novel laser-based, high-brightness, high-spatial-resolution, pencil-beam sources of spectrally pure hard x-ray and gamma-ray radiation to induce resonant scattering in specific nuclei, i.e., nuclear resonance fluorescence. By monitoring such fluorescence as a function of beam position, it is possible to image in either two dimensions or three dimensions, the position and concentration of individual isotopes in a specific material configuration. Such methods of the present invention material identification, spatial resolution of material location and ability to locate and identify materials shielded by other materials, such as, for example, behind a lead wall. The foundation of the present invention is the generation of quasimonochromatic high-energy x-ray (100's of keV) and gamma-ray (greater than about 1 MeV) radiation via the collision of intense laser pulses from relativistic electrons. Such a process as utilized herein, i.e., Thomson scattering or inverse-Compton scattering, produces beams having diameters from about 1 micron to about 100 microns of high-energy photons with a bandwidth of .DELTA.E/E of approximately 10E.sup.-3.

  9. Los Alamos activities on HE detection using nuclear resonance absorption technique

    SciTech Connect

    Kwan, T. J. T.

    2004-01-01

    The feasibility of detecting high explosives through the nitrogen nuclear resonance absorption of the 9.17-MeV gammas produced by carbon-13 nuclei via radiative capture of 1.75-MeV protons was demonstrated almost ten years ago at Los Alamos National Laboratory. The practical application of this technique requires advances in several enabling technologies. The most important issue is the generation of a high quality proton beam with appreciable current (>10 mA) to produce the minimum number of resonance gammas to achieve the required throughput in baggage/cargo interrogation. We have performed a parameter study of the use of a compact cyclotron as an injector to a proton storage ring with energy recovery and electron cooling capability to maximize the intensity of the proton beam. We have also started our computational effort in applying MCNPX in our newly developed radiographic chain model to model the radiographic imaging process. Details of our studies will be presented.

  10. Extending Nuclear Magnetic Resonance Data for Permeability Estimation in Fine-Grained Sediments

    NASA Astrophysics Data System (ADS)

    Daigle, H.; Dugan, B.

    2008-12-01

    We developed a method for using nuclear magnetic resonance (NMR) T2 data and gamma ray data to estimate lithology-dependent permeability in silt- and clay-rich sediments. This model, based on the Schlumberger-Doll Research (SDR) model, allows for high resolution (<1 m) permeability estimates throughout a logged interval. Our model was calibrated using direct measurements on core samples from Keathley Canyon Lease Block 151 in the northern Gulf of Mexico. From NMR and gamma ray data we are able to determine permeability from 10-18 to 10-14 m2 (0.001 to 10 millidarcies). Thus from discrete core samples and log data we were able to develop a permeability model for the entire sedimentary column (425 m). Lithologic variation was incorporated into the model by varying the A coefficient based on the gamma ray response. This provides a more accurate permeability model than assigning a constant value to A as is typically done. The relationship between A and intrinsic lithologic properties is unclear; simple pore system models suggest that A may be related to specific surface, tortuosity, and pore structure; we investigate simple models to quantify how these properties vary with sediment consolidation and what their relationship is to A. A comprehensive understanding that links NMR data and A to pore-scale properties will provide new constraints on deformation and flow in porous systems, and will contribute to our understanding of sediment properties for fluid flow modeling at local and regional scales.

  11. Double-resonance 14N nuclear-magnetic-resonance probe for single-crystal studies

    NASA Astrophysics Data System (ADS)

    Naito, Akira; McDowell, Charles A.

    1989-06-01

    A double-resonance 14N nuclear-magnetic-resonance (NMR) probe suitable for single-crystal studies is described. The 14N and 1H sample coils are wound as coaxial solenoids and used instead of a doubly tuned single coil to tune over the required frequency range of the 14N channel. The choice of materials for the probe body and the wire size for the sample and impedance matching coils were chosen carefully to minimize spurious ringing phenomena, which is troublesome in probe designs for solid-state NMR. The probe has a very accurate goniometer since the resolution of 14N NMR signals is high.

  12. Physics with gamma-beams and charged particle detectors: I) Nuclear structure II) Nuclear astrophysics

    SciTech Connect

    Gai, Moshe

    2015-02-24

    The Charged Particle Working Group (CPWG) is proposing to construct large area Silicon Strip Detector (SSD), a gas Time Projection Chamber detector read by an electronic readout system (eTPC) and a Bubble Chamber (BC) containing superheated high purity water to be used in measurements utilizing intense gamma-ray beams from the newly constructed ELI-NP facility at Magurele, Bucharest in Romania. We intend to use the SSD and eTPC detectors to address essential problems in nuclear structure physics, such as clustering and the many alpha-decay of light nuclei such as {sup 12}C and {sup 16}O. All three detectors (SSD, eTPC and BC) will be used to address central problems in nuclear astrophysics such as the astrophysical cross section factor of the {sup 12}C(α,γ) reaction and other processes central to stellar evolution. The CPWG intends to submit to the ELI-NP facility a Technical Design Report (TDR) for the proposed detectors.

  13. Physics with gamma-beams and charged particle detectors: I) Nuclear structure II) Nuclear astrophysics

    NASA Astrophysics Data System (ADS)

    Gai, Moshe

    2015-02-01

    The Charged Particle Working Group (CPWG) is proposing to construct large area Silicon Strip Detector (SSD), a gas Time Projection Chamber detector read by an electronic readout system (eTPC) and a Bubble Chamber (BC) containing superheated high purity water to be used in measurements utilizing intense gamma-ray beams from the newly constructed ELI-NP facility at Magurele, Bucharest in Romania. We intend to use the SSD and eTPC detectors to address essential problems in nuclear structure physics, such as clustering and the many alpha-decay of light nuclei such as 12C and 16O . All three detectors (SSD, eTPC and BC) will be used to address central problems in nuclear astrophysics such as the astrophysical cross section factor of the 12C (α,γ) reaction and other processes central to stellar evolution. The CPWG intends to submit to the ELI-NP facility a Technical Design Report (TDR) for the proposed detectors.

  14. Single crystal nuclear magnetic resonance in spinning powders.

    PubMed

    Pell, Andrew J; Pintacuda, Guido; Emsley, Lyndon

    2011-10-14

    We present a method for selectively exciting nuclear magnetic resonances (NMRs) from well-defined subsets of crystallites from a powdered sample under magic angle spinning. Magic angle spinning induces a time dependence in the anisotropic interactions, which results in a time variation of the resonance frequencies which is different for different crystallite orientations. The proposed method exploits this by applying selective pulses, which we refer to as XS (for crystallite-selective) pulses, that follow the resonance frequencies of nuclear species within particular crystallites, resulting in the induced flip angle being orientation dependent. By selecting the radiofrequency field to deliver a 180° pulse for the target orientation and employing a train of such pulses combined with cogwheel phase cycling, we obtain a high degree of orientational selectivity with the resulting spectrum containing only contributions from orientations close to the target. Typically, this leads to the selection of between 0.1% and 10% of the crystallites, and in extreme cases to the excitation of a single orientation resulting in single crystal spectra of spinning powders. Two formulations of this method are described and demonstrated with experimental examples on [1-(13)C]-alanine and the paramagnetic compound Sm(2)Sn(2)O(7).

  15. Single crystal nuclear magnetic resonance in spinning powders

    NASA Astrophysics Data System (ADS)

    Pell, Andrew J.; Pintacuda, Guido; Emsley, Lyndon

    2011-10-01

    We present a method for selectively exciting nuclear magnetic resonances (NMRs) from well-defined subsets of crystallites from a powdered sample under magic angle spinning. Magic angle spinning induces a time dependence in the anisotropic interactions, which results in a time variation of the resonance frequencies which is different for different crystallite orientations. The proposed method exploits this by applying selective pulses, which we refer to as XS (for crystallite-selective) pulses, that follow the resonance frequencies of nuclear species within particular crystallites, resulting in the induced flip angle being orientation dependent. By selecting the radiofrequency field to deliver a 180 ○ pulse for the target orientation and employing a train of such pulses combined with cogwheel phase cycling, we obtain a high degree of orientational selectivity with the resulting spectrum containing only contributions from orientations close to the target. Typically, this leads to the selection of between 0.1% and 10% of the crystallites, and in extreme cases to the excitation of a single orientation resulting in single crystal spectra of spinning powders. Two formulations of this method are described and demonstrated with experimental examples on [1 - 13C]-alanine and the paramagnetic compound Sm2Sn2O7.

  16. Enabling in situ thermometry using transmission nuclear resonance fluorescence

    NASA Astrophysics Data System (ADS)

    Angell, Christopher T.

    2016-02-01

    Transmission nuclear resonance fluorescence (NRF) has been proposed for use as an assay and detection technique for nuclear security and safeguards applications because of its isotope-specific sensitivity and the penetrating capability of γ -rays. It can also be used for in situ thermometry because the absorbing resonance profile is sensitive to temperature. Using transmission NRF for thermometry could provide a new avenue for studying the ion temperature evolution of laser-induced plasmas using the upcoming ELI-NP facility. It could also be used for applications where thermometry would be otherwise infeasible, such as for determining the average fuel temperature of spent nuclear fuel, a step that would reduce the assay uncertainty using transmission NRF. In this paper, two different transmission NRF thermometry scenarios are presented and analyzed for sensitivity. This analysis demonstrated that thermometry using γ -rays is possible independent of γ -ray beam type and will be feasible with next-generation high-intensity γ -ray sources. Beyond thermometry, an application of temperature effects was found in the improvement of transmission NRF efficacy for assay and detection: using a cryogenic witness target will reduce the required measurement time by 40%.

  17. Proton nuclear magnetic resonance study of hirudin: resonance assignment and secondary structure

    SciTech Connect

    Sukumaran, D.K.; Clore, G.M.; Preuss, A.; Zarbock, J.; Gronenbron, A.M.

    1987-01-27

    The /sup 1/H NMR spectrum of the 65-residue protein hirudin is assigned in a sequential manner by using a combination of two-dimensional nuclear magnetic resonance techniques to demonstrate through-bond and through space (<5-A) connectives. The secondary structure of hirudin is deduced from a qualitative interpretation of the nuclear Overhauser effects involving the backbone NH, C/sup ..cap alpha../H, and C/sup ..beta../H protons. It is shown that hirudin has two ..beta..-sheets and no ..cap alpha..-helices.

  18. Gamma-resonance Contraband Detection using a high current tandem accelerator

    SciTech Connect

    Milton, B. F.; Beis, J.; Dale, D.; Rogers, J.; Ruegg, R.; Debiak, T.; Kamykowski, E.; Melnychuk, S.; Rathke, J.; Sredniawski, J.

    1999-04-26

    TRIUMF and Northrop Grumman have developed a new system for the detection of concealed explosives and drugs. This Contraband Detection System (CDS) is based on the resonant absorption by {sup 14}N of gammas produced using {sup 13}C(p,{gamma}){sup 14}N. The chosen reaction uses protons at 1.75 MeV and the gammas have an energy of 9.17 MeV. By measuring both the resonant and the non-resonant absorption using detectors with good spatial resolution, and applying standard tomographic techniques, we are able to produce 3D images of both the nitrogen partial density and the total density. The images together may be utilized with considerable confidence to determine if small amounts of nitrogen based explosives, heroin or cocaine are present in the interrogated containers. Practical Gamma Resonant Absorption (GRA) scanning requires an intense source of protons. However this proton source must also be very stable, have low energy spread, and have good spatial definition. These demands suggested a tandem as the accelerator of choice. We have therefore constructed a 2 MeV H{sup -} tandem optimized for high current (10 mA) operation, while minimizing the overall size of the accelerator. This has required several special innovations which will be presented in the paper. We will also present initial commissioning results.

  19. Phosphorus nuclear magnetic resonance in isolated perfused rat pancreas

    SciTech Connect

    Matsumoto, Takehisa; Kanno, Tomio; Seo, Yoshiteru; Murakami, Masataka; Watari, Hiroshi National Institute for Physiological Sciences, Okazaki )

    1988-04-01

    Phosphorus nuclear magnetic resonance spectroscopy was applied to measure phosphorus energy metabolites in isolated perfused rat pancreas. The gland was perfused with a modified Krebs-Henseleit solution at room temperature (25{degree}C). {sup 31}P resonances of creatine phosphate (PCr), ATP, ADP, inorganic phosphate (P{sub i}) and phosphomonoesters (PMEs) were observed in all the preparations of pancreas. In different individual preparations, the resonance of PCr varied, but those of ATP were almost the same. The initial levels of PCr and ATP in individual preparations, however, remained almost unchanged during perfusion with the standard solution for 2 h. When the perfusion was stopped, the levels of ATP and PCr decreased, while the levels of PME and P{sub i} increased. At that time, the P{sub i} resonance shfted to a higher magnetic field, indicating that the tissue pH decreased. On reperfusion, the tissue levels of phosphorus compounds and the tissue pH were restored to their initial resting levels. Continuous infusion of 0.1 {mu}M acetylcholine caused marked and sustained increases in the flow of pancreatic juice and protein output. During the stimulation the tissue levels of phosphorus compounds remained unchanged, while the tissue pH was decreased slightly.

  20. Bonner Prize Talk: Parity Violation in Compound-Nuclear Resonances

    NASA Astrophysics Data System (ADS)

    Bowman, J. David

    2002-04-01

    I will describe a series of experiments that observed large parity-violating asymmetries in the scattering of polarized neutrons from a number of nuclei. I will review statistical models of compound-nuclear resonances and the statistical interpretation of observables. I will present the results of the experiments and the analysis of the measured asymmetries to extract the strength function of the nuclear weak interaction. In A=232 10 of 10 measured asymmetries had a common sign, in contradiction to the predictions of statistical models. I will describe the interpretation of this phenomenon in terms of doorway states. I will summarize the status of theoretical efforts to obtain constraints on the couplings of the hadronic weak interaction from measured weak strength functions.

  1. Nuclear-magnetic-resonance quantum calculations of the Jones polynomial

    PubMed Central

    Marx, Raimund; Fahmy, Amr; Kauffman, Louis; Lomonaco, Samuel; Spörl, Andreas; Pomplun, Nikolas; Schulte-Herbrüggen, Thomas; Myers, John M.; Glaser, Steffen J.

    2011-01-01

    The repertoire of problems theoretically solvable by a quantum computer recently expanded to include the approximate evaluation of knot invariants, specifically the Jones polynomial. The experimental implementation of this evaluation, however, involves many known experimental challenges. Here we present experimental results for small-scale approximate evaluation of the Jones polynomial by nuclear magnetic resonance (NMR); in addition, we show how to escape from the limitations of NMR approaches that employ pseudopure states. Specifically, we use two spin-1/2 nuclei of natural abundance chloroform and apply a sequence of unitary transforms representing the trefoil knot, the figure-eight knot, and the Borromean rings. After measuring the nuclear spin state of the molecule in each case, we are able to estimate the value of the Jones polynomial for each of the knots. PMID:21461143

  2. A highly integrated FPGA-based nuclear magnetic resonance spectrometer

    NASA Astrophysics Data System (ADS)

    Takeda, Kazuyuki

    2007-03-01

    The digital circuits required for a nuclear magnetic resonance (NMR) spectrometer, including a pulse programmer, a direct digital synthesizer, a digital receiver, and a PC interface, have been built inside a single chip of the field-programmable gate-array (FPGA). By combining the FPGA chip with peripheral analog components, a compact, laptop-sized homebuilt spectrometer has been developed, which is capable of a rf output of up to 400 MHz with amplitude-, phase-, frequency-, and pulse-modulation. The number of rf channels is extendable up to three without further increase in size.

  3. A highly integrated FPGA-based nuclear magnetic resonance spectrometer.

    PubMed

    Takeda, Kazuyuki

    2007-03-01

    The digital circuits required for a nuclear magnetic resonance (NMR) spectrometer, including a pulse programmer, a direct digital synthesizer, a digital receiver, and a PC interface, have been built inside a single chip of the field-programmable gate-array (FPGA). By combining the FPGA chip with peripheral analog components, a compact, laptop-sized homebuilt spectrometer has been developed, which is capable of a rf output of up to 400 MHz with amplitude-, phase-, frequency-, and pulse-modulation. The number of rf channels is extendable up to three without further increase in size.

  4. Applications of nuclear magnetic resonance sensors to cultural heritage.

    PubMed

    Proietti, Noemi; Capitani, Donatella; Di Tullio, Valeria

    2014-04-21

    In recent years nuclear magnetic resonance (NMR) sensors have been increasingly applied to investigate, characterize and monitor objects of cultural heritage interest. NMR is not confined to a few specific applications, but rather its use can be successfully extended to a wide number of different cultural heritage issues. A breakthrough has surely been the recent development of portable NMR sensors which can be applied in situ for non-destructive and non-invasive investigations. In this paper three studies illustrating the potential of NMR sensors in this field of research are reported.

  5. Stochastic Dipolar Recoupling in Nuclear Magnetic Resonance of Solids

    SciTech Connect

    Tycko, Robert

    2007-11-02

    I describe a nuclear magnetic resonance (NMR) technique, called stochastic dipolar recoupling (SDR), that permits continuous experimental control of the character of spin dynamics between coherent and incoherent limits in a system of magnetic dipole-coupled nuclei. In the fully incoherent limit of SDR, spin polarization transfers occur at distance-dependent rates without the quantum mechanical interferences among pairwise dipole-dipole couplings that often limit the feasibility or precision of structural studies of solids by NMR. In addition to facilitating structural studies, SDR represents a possible route to experimental studies of effects of decoherence on the dynamics of quantum many-body system000.

  6. Applications of Nuclear Magnetic Resonance Sensors to Cultural Heritage

    PubMed Central

    Proietti, Noemi; Capitani, Donatella; Di Tullio, Valeria

    2014-01-01

    In recent years nuclear magnetic resonance (NMR) sensors have been increasingly applied to investigate, characterize and monitor objects of cultural heritage interest. NMR is not confined to a few specific applications, but rather its use can be successfully extended to a wide number of different cultural heritage issues. A breakthrough has surely been the recent development of portable NMR sensors which can be applied in situ for non-destructive and non-invasive investigations. In this paper three studies illustrating the potential of NMR sensors in this field of research are reported. PMID:24755519

  7. Flat RF coils in static field gradient nuclear magnetic resonance.

    PubMed

    Stork, H; Gädke, A; Nestle, N; Fujara, F

    2009-10-01

    The use of flat RF coils allows considerable gains in the sensitivity of static field gradient (SFG) nuclear magnetic resonance (NMR) experiments. In this article, this effect is studied theoretically as well as experimentally. Additionally, the flat coil geometry has been studied theoretically depending on magnetic field gradient, pulse sequence and amplifier power. Moreover, detecting the signal directly from the free induction decay (FID) turned out to be quite attractive for STRAFI-like microimaging experiments, especially when using flat coils. In addition to wound rectangular flat coils also spiral flat coils have been developed which can be manufactured by photolithography from printed circuit boards.

  8. A versatile pulse programmer for pulsed nuclear magnetic resonance spectroscopy.

    NASA Technical Reports Server (NTRS)

    Tarr, C. E.; Nickerson, M. A.

    1972-01-01

    A digital pulse programmer producing the standard pulse sequences required for pulsed nuclear magnetic resonance spectroscopy is described. In addition, a 'saturation burst' sequence, useful in the measurement of long relaxation times in solids, is provided. Both positive and negative 4 V trigger pulses are produced that are fully synchronous with a crystal-controlled time base, and the pulse programmer may be phase-locked with a maximum pulse jitter of 3 ns to the oscillator of a coherent pulse spectrometer. Medium speed TTL integrated circuits are used throughout.

  9. Stochastic dipolar recoupling in nuclear magnetic resonance of solids.

    PubMed

    Tycko, Robert

    2007-11-02

    I describe a nuclear magnetic resonance (NMR) technique, called stochastic dipolar recoupling (SDR), that permits continuous experimental control of the character of spin dynamics between coherent and incoherent limits in a system of magnetic dipole-coupled nuclei. In the fully incoherent limit of SDR, spin polarization transfers occur at distance-dependent rates without the quantum mechanical interferences among pairwise dipole-dipole couplings that often limit the feasibility or precision of structural studies of solids by NMR. In addition to facilitating structural studies, SDR represents a possible route to experimental studies of effects of decoherence on the dynamics of quantum many-body systems.

  10. Nuclear Magnetic Resonance Applications to Unconventional Fossil Fuel Resources

    NASA Astrophysics Data System (ADS)

    Kleinberg, R. L.; Leu, G.

    2008-12-01

    Technical and economic projections strongly suggest that fossil fuels will continue to play a dominant role in the global energy market through at least the mid twenty-first century. However, low-cost conventional oil and gas will be depleted in that time frame. Therefore new sources of energy will be needed. We discuss two relatively untapped unconventional fossil fuels: heavy oil and gas hydrate. In both cases, nuclear magnetic resonance plays a key role in appraising the resource and providing information needed for designing production processes.

  11. Nuclear quadrupole resonance studies project. [spectrometer design and spectrum analysis

    NASA Technical Reports Server (NTRS)

    Murty, A. N.

    1978-01-01

    The participation of undergraduates in nuclear quadrupole resonance research at Grambling University was made possible by NASA grants. Expanded laboratory capabilities include (1) facilities for high and low temperature generation and measurement; (2) facilities for radio frequency generation and measurement with the modern spectrum analyzers, precision frequency counters and standard signal generators; (3) vacuum and glass blowing facilities; and (4) miscellaneous electronic and machine shop facilities. Experiments carried out over a five year period are described and their results analyzed. Theoretical studies on solid state crystalline electrostatic fields, field gradients, and antishielding factors are included.

  12. Nuclear magnetic resonance: principles of blood flow imaging

    SciTech Connect

    Mills, C.M.; Brant-Zawadzki, M.; Crooks, L.E.; Kaufman, L.; Sheldon, P.; Norman, D.; Bank, W.; Newton, T.H.

    1984-01-01

    Nuclear magnetic resonance (NMR) imaging with spin-echo techniques defines vascular structures with superb anatomic detail. Contrast agents are not necessary as there is intrinsic contrast between flowing blood and the vascular wall. The signal intensity from blood within the vessel lumen varies with the sequence of gradient and radiofrequency pulses used to generate the image as well as with the velocity of blood flow. Appropriate imaging techniques can optimize anatomic detail, distinguish slow from rapidly flowing blood, and serve to identify marked impairment or complete obstruction of flow in an artery or vein. Some examples of these principles in the intracranial circulation are illustrated.

  13. Stochastic dipolar recoupling in nuclear magnetic resonance of solids

    PubMed Central

    Tycko, Robert

    2008-01-01

    I describe a nuclear magnetic resonance (NMR) technique, called stochastic dipolar recoupling (SDR), that permits continuous experimental control of the character of spin dynamics between coherent and incoherent limits in a system of magnetic dipole-coupled nuclei. In the fully incoherent limit of SDR, spin polarization transfers occur at distance-dependent rates without the quantum mechanical interferences among pairwise dipole-dipole couplings that often limit the feasibility or precision of structural studies of solids by NMR. In addition to facilitating structural studies, SDR represents a possible route to experimental studies of effects of decoherence on the dynamics of quantum many-body systems. PMID:17995438

  14. Random matrix theory in biological nuclear magnetic resonance spectroscopy.

    PubMed Central

    Lacelle, S

    1984-01-01

    The statistical theory of energy levels or random matrix theory is presented in the context of the analysis of chemical shifts of nuclear magnetic resonance (NMR) spectra of large biological systems. Distribution functions for the spacing between nearest-neighbor energy levels are discussed for uncorrelated, correlated, and random superposition of correlated energy levels. Application of this approach to the NMR spectra of a vitamin, an antibiotic, and a protein demonstrates the state of correlation of an ensemble of energy levels that characterizes each system. The detection of coherent and dissipative structures in proteins becomes feasible with this statistical spectroscopic technique. PMID:6478032

  15. Nuclear resonance scattering measurement of human iron stores

    SciTech Connect

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

    1985-07-01

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

  16. Nuclear magnetic resonance-based quantification of organic diphosphates.

    PubMed

    Lenevich, Stepan; Distefano, Mark D

    2011-01-15

    Phosphorylated compounds are ubiquitous in life. Given their central role, many such substrates and analogs have been prepared for subsequent evaluation. Prior to biological experiments, it is typically necessary to determine the concentration of the target molecule in solution. Here we describe a method where concentrations of stock solutions of organic diphosphates and bisphosphonates are quantified using (31)P nuclear magnetic resonance (NMR) spectroscopy with standard instrumentation using a capillary tube with a secondary standard. The method is specific and is applicable down to a concentration of 200 μM. The capillary tube provides the reference peak for quantification and deuterated solvent for locking.

  17. Nuclear Magnetic Resonance Study of Uranium BERYLLIUM(13 - Boron(x)

    NASA Astrophysics Data System (ADS)

    Ahrens, Eric Thomas

    Nuclear magnetic resonance (NMR) measurements in the heavy fermion compound UBe_{13 -x}{B}_{x} for x = 0.030 and 0.067 in the temperature (T) range from 0.096 to 300 K are reported. Within a given sample we are able to detect resonances from three nuclei: ^9Be, ^{11}B, and ^{10}B. Analysis of the NMR spectra of these three nuclei show an exclusive substitution site for the B dopant into the m3 or cubic site of the UBe_{13} lattice. The nominal values of the B concentrations and a single phase sample composition is confirmed using NMR by a measurement of the relative number of ^{11}B to ^9Be nuclei in each sample. Normal state ^{11 }B magnetic shift (K_{m }) measurements exhibit the same T dependence as the static magnetic susceptibility(X_ {m}). From the slope of the linear plot of K_{m} verses X _{m}, the ^{11 }B hyperfine field (H_{hf }) is determined to be -361.1 Oe/mu_{B}. The magnetic shift is independent of B concentration. Normal state spin-lattice relaxation rate (1/T_1) measurements of ^{11} B as a function of T reveal two energy scales in the magnetic response of these materials. The T dependence of the normal state electronic fluctuation rate ( Gamma) of the U^{3+ } moments is calculated using the results of 1/T_1, X_{m}, and H_{hf} measurements. At T<2{K}, Gamma~1 meV for x = 0.030, which is in agreement with the width of the narrow feature in the density of states at the Fermi energy needed to give the large values of the low temperature electronic specific heat coefficient and magnetic susceptibility. At higher temperatures Gamma~sqrt{T} which is characteristic of isolated local moments. For T>60 K the occurrence of crystal field splittings introduce a second energy scale that destroys the sqrt{T} behavior. The results of Gamma for x = 0.030 are in quantitative agreement with quasi-elastic and inelastic neutron scattering measurements in UBe_{13}. We observe no evidence for antiferromagnetic spin correlations down to 2 K. The x = 0.067 sample shows a

  18. A multifrequency high-field pulsed electron paramagnetic resonance/electron-nuclear double resonance spectrometer

    NASA Astrophysics Data System (ADS)

    Morley, Gavin W.; Brunel, Louis-Claude; van Tol, Johan

    2008-06-01

    We describe a pulsed electron paramagnetic resonance spectrometer operating at several frequencies in the range of 110-336GHz. The microwave source at all frequencies consists of a multiplier chain starting from a solid state synthesizer in the 12-15GHz range. A fast p-i-n-switch at the base frequency creates the pulses. At all frequencies a Fabry-Pérot resonator is employed and the π /2 pulse length ranges from ˜100ns at 110GHzto˜600ns at 334GHz. Measurements of a single crystal containing dilute Mn2+ impurities at 12T illustrate the effects of large electron spin polarizations. The capabilities also allow for pulsed electron-nuclear double resonance (ENDOR) experiments as demonstrated by Mims ENDOR of K39 nuclei in Cr :K3NbO8.

  19. Nuclear Structure of {sup 8}B Studied by Proton Resonance Scatterings on {sup 7}Be

    SciTech Connect

    Yamaguchi, H.; Wakabayashi, Y.; Hayakawa, S.; Amadio, G.; Kubono, S.; Fujikawa, H.; Niikura, M.; Binh, D. N.; Saito, A.; He, J. J.; Teranishi, T.; Kwon, Y. K.; Nishimura, S.; Togano, Y.; Iwasa, N.; Inafuku, K.; Khiem, L. H.

    2008-05-21

    A new measurement of the proton resonance scattering on {sup 7}Be was performed up to the excitation energy of 6.8 MeV using the low-energy RI beam facility CRIB (CNS Radioactive Ion Beam separator) at the Center for Nuclear Study (CNS) of the University of Tokyo. The excitation function of {sup 8}B above 3.5 MeV was successfully measured for the first time, providing important information about the reaction rate of {sup 7}Be(p,{gamma}){sup 8}B, which is the key reaction in the solar {sup 8}B neutrino production. For more intensive experimental studies with RI beams, the development of a cryogenic gas target system is ongoing at CNS. In this paper a preliminary result of the {sup 7}Be experiment and the present status of the development of the target system are presented.

  20. A loop-gap resonator for chirality-sensitive nuclear magneto-electric resonance (NMER)

    NASA Astrophysics Data System (ADS)

    Garbacz, Piotr; Fischer, Peer; Krämer, Steffen

    2016-09-01

    Direct detection of molecular chirality is practically impossible by methods of standard nuclear magnetic resonance (NMR) that is based on interactions involving magnetic-dipole and magnetic-field operators. However, theoretical studies provide a possible direct probe of chirality by exploiting an enantiomer selective additional coupling involving magnetic-dipole, magnetic-field, and electric field operators. This offers a way for direct experimental detection of chirality by nuclear magneto-electric resonance (NMER). This method uses both resonant magnetic and electric radiofrequency (RF) fields. The weakness of the chiral interaction though requires a large electric RF field and a small transverse RF magnetic field over the sample volume, which is a non-trivial constraint. In this study, we present a detailed study of the NMER concept and a possible experimental realization based on a loop-gap resonator. For this original device, the basic principle and numerical studies as well as fabrication and measurements of the frequency dependence of the scattering parameter are reported. By simulating the NMER spin dynamics for our device and taking the 19F NMER signal of enantiomer-pure 1,1,1-trifluoropropan-2-ol, we predict a chirality induced NMER signal that accounts for 1%-5% of the standard achiral NMR signal.

  1. A loop-gap resonator for chirality-sensitive nuclear magneto-electric resonance (NMER).

    PubMed

    Garbacz, Piotr; Fischer, Peer; Krämer, Steffen

    2016-09-14

    Direct detection of molecular chirality is practically impossible by methods of standard nuclear magnetic resonance (NMR) that is based on interactions involving magnetic-dipole and magnetic-field operators. However, theoretical studies provide a possible direct probe of chirality by exploiting an enantiomer selective additional coupling involving magnetic-dipole, magnetic-field, and electric field operators. This offers a way for direct experimental detection of chirality by nuclear magneto-electric resonance (NMER). This method uses both resonant magnetic and electric radiofrequency (RF) fields. The weakness of the chiral interaction though requires a large electric RF field and a small transverse RF magnetic field over the sample volume, which is a non-trivial constraint. In this study, we present a detailed study of the NMER concept and a possible experimental realization based on a loop-gap resonator. For this original device, the basic principle and numerical studies as well as fabrication and measurements of the frequency dependence of the scattering parameter are reported. By simulating the NMER spin dynamics for our device and taking the (19)F NMER signal of enantiomer-pure 1,1,1-trifluoropropan-2-ol, we predict a chirality induced NMER signal that accounts for 1%-5% of the standard achiral NMR signal.

  2. Coherent nuclear resonant scattering by {sup 61}Ni using the nuclear lighthouse effect

    SciTech Connect

    Roth, T.; Leupold, O.; Wille, H.-C.; Rueffer, R.; Quast, K.W.; Burkel, E.; Roehlsberger, R.

    2005-04-01

    We have observed coherent nuclear resonant scattering of synchrotron radiation from the 67.41-keV level of {sup 61}Ni. The time evolution of the forward scattering signal was recorded by employing the nuclear lighthouse effect. This method is used to investigate Moessbauer isotopes in a coherent scattering process with synchrotron radiation at high transition energies. The decay of the excited ensemble of nuclei in Ni metal shows quantum beats that allowed the determination of the magnetic hyperfine field at the {sup 61}Ni nucleus. Moreover, we determined the lifetime of the 67.41-keV level of {sup 61}Ni to be 7.4(1) ns.

  3. Nuclear Fusion Rate Study of a Muonic Molecule via Nuclear Threshold Resonances

    NASA Astrophysics Data System (ADS)

    Faghihi, F.; Eskandari, M. R.

    This work follows our previous calculations of the ground state binding energy, size, and the effective nuclear charge of the muonic T3 molecule, using the Born-Oppenheimer adiabatic approximation. In our past articles, we showed that the system possesses two minimum positions, the first one at the muonic distance and the second at the atomic distance. Also, the symmetric planner vibrational model assumed between the two minima and the approximated potential were calculated. Following from the previous studies, we now calculate the fusion rate of the T3 muonic molecule according to the overlap integral of the resonance nuclear compound nucleus and the molecular wave functions.

  4. Inverse Analysis of Irradiated NuclearMaterial Gamma Spectra via Nonlinear Optimization

    NASA Astrophysics Data System (ADS)

    Dean, Garrett James

    Nuclear forensics is the collection of technical methods used to identify the provenance of nuclear material interdicted outside of regulatory control. Techniques employed in nuclear forensics include optical microscopy, gas chromatography, mass spectrometry, and alpha, beta, and gamma spectrometry. This dissertation focuses on the application of inverse analysis to gamma spectroscopy to estimate the history of pulse irradiated nuclear material. Previous work in this area has (1) utilized destructive analysis techniques to supplement the nondestructive gamma measurements, and (2) been applied to samples composed of spent nuclear fuel with long irradiation and cooling times. Previous analyses have employed local nonlinear solvers, simple empirical models of gamma spectral features, and simple detector models of gamma spectral features. The algorithm described in this dissertation uses a forward model of the irradiation and measurement process within a global nonlinear optimizer to estimate the unknown irradiation history of pulse irradiated nuclear material. The forward model includes a detector response function for photopeaks only. The algorithm uses a novel hybrid global and local search algorithm to quickly estimate the irradiation parameters, including neutron fluence, cooling time and original composition. Sequential, time correlated series of measurements are used to reduce the uncertainty in the estimated irradiation parameters. This algorithm allows for in situ measurements of interdicted irradiated material. The increase in analysis speed comes with a decrease in information that can be determined, but the sample fluence, cooling time, and composition can be determined within minutes of a measurement. Furthermore, pulse irradiated nuclear material has a characteristic feature that irradiation time and flux cannot be independently estimated. The algorithm has been tested against pulse irradiated samples of pure special nuclear material with cooling times of

  5. Simple and Inexpensive Classroom Demonstrations of Nuclear Magnetic Resonance and Magnetic Resonance Imaging

    NASA Astrophysics Data System (ADS)

    Olson, Joel A.; Nordell, Karen J.; Chesnik, Marla A.; Landis, Clark R.; Ellis, Arthur B.; Rzchowski, M. S.; Condren, S. Michael; Lisensky, George C.

    2000-07-01

    Several demonstrations of resonance phenomena associated with nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) are described. The demonstrations comprise common orienteering compasses, whose needles represent magnetic dipoles, along with three collinear permanent magnets and a magnetic stir plate or pulseable electromagnets. The trio of permanent magnets provides a laterally uniform magnetic field, whose strength decreases with distance from the magnets. Resonance can be observed by adjusting the frequency of the magnetic stirrer to match the resonant frequency of the compass needle, which is shown to depend on magnetic field strength, that is, the needle's position relative to the permanent magnets. Another demonstration involves pulsing electromagnets that apply a perpendicular magnetic field that causes the compass needles to oscillate. The effects of shielding, spin-spin coupling, magnetogyric ratio, and free induction decay can also be demonstrated. By moving the trio of permanent magnets relative to the compasses, the MRI experiment can be mimicked. Complete instructions for the construction of the demonstrations, which can be used on an overhead projector, are included.

  6. A dual neutron/gamma source for the Fissmat Inspection for Nuclear Detection (FIND) system.

    SciTech Connect

    Doyle, Barney Lee; King, Michael; Rossi, Paolo; McDaniel, Floyd Del; Morse, Daniel Henry; Antolak, Arlyn J.; Provencio, Paula Polyak; Raber, Thomas N.

    2008-12-01

    Shielded special nuclear material (SNM) is very difficult to detect and new technologies are needed to clear alarms and verify the presence of SNM. High-energy photons and neutrons can be used to actively interrogate for heavily shielded SNM, such as highly enriched uranium (HEU), since neutrons can penetrate gamma-ray shielding and gamma-rays can penetrate neutron shielding. Both source particles then induce unique detectable signals from fission. In this LDRD, we explored a new type of interrogation source that uses low-energy proton- or deuteron-induced nuclear reactions to generate high fluxes of mono-energetic gammas or neutrons. Accelerator-based experiments, computational studies, and prototype source tests were performed to obtain a better understanding of (1) the flux requirements, (2) fission-induced signals, background, and interferences, and (3) operational performance of the source. The results of this research led to the development and testing of an axial-type gamma tube source and the design/construction of a high power coaxial-type gamma generator based on the {sup 11}B(p,{gamma}){sup 12}C nuclear reaction.

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

    NASA Astrophysics Data System (ADS)

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

    2013-03-01

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

  8. Delayed Gamma-ray Spectroscopy for Non-Destructive Assay of Nuclear Materials

    SciTech Connect

    Mozin, Vladimir; Ludewigt, Bernhard; Campbell, Luke; Favalli, Andrea; Hunt, Alan

    2014-10-09

    This project addresses the need for improved non-destructive assay techniques for quantifying the actinide composition of spent nuclear fuel and for the independent verification of declared quantities of special nuclear materials at key stages of the fuel cycle. High-energy delayed gamma-ray spectroscopy following neutron irradiation is a potential technique for directly assaying spent fuel assemblies and achieving the safeguards goal of quantifying nuclear material inventories for spent fuel handling, interim storage, reprocessing facilities, repository sites, and final disposal. Other potential applications include determination of MOX fuel composition, characterization of nuclear waste packages, and challenges in homeland security and arms control verification.

  9. Decoherence and fluctuation dynamics of the quantum dot nuclear spin bath probed by nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Chekhovich, Evgeny A.

    2017-06-01

    Dynamics of nuclear spin decoherence and nuclear spin flip-flops in self-assembled InGaAs/GaAs quantum dots are studied experimentally using optically detected nuclear magnetic resonance (NMR). Nuclear spin-echo decay times are found to be in the range 1-4 ms. This is a factor of ~3 longer than in strain-free GaAs/AlGaAs structures and is shown to result from strain-induced quadrupolar effects that suppress nuclear spin flip-flops. The correlation times of the flip-flops are examined using a novel frequency-comb NMR technique and are found to exceed 1 s, a factor of ~1000 longer than in strain-free structures. These findings complement recent studies of electron spin coherence and reveal the paradoxical dual role of the quadrupolar effects in self-assembled quantum dots: large increase of the nuclear spin bath coherence and at the same time significant reduction of the electron spin-qubit coherence. Approaches to increasing electron spin coherence are discussed. In particular the nanohole filled GaAs/AlGaAs quantum dots are an attractive option: while their optical quality matches the self-assembled dots the quadrupolar effects measured in NMR spectra are a factor of 1000 smaller.

  10. The Fourier Transform in Chemistry. Part 1. Nuclear Magnetic Resonance: Introduction.

    ERIC Educational Resources Information Center

    King, Roy W.; Williams, Kathryn R.

    1989-01-01

    Using fourier transformation methods in nuclear magnetic resonance has made possible increased sensitivity in chemical analysis. This article describes these methods as they relate to magnetization, the RF magnetic field, nuclear relaxation, the RF pulse, and free induction decay. (CW)

  11. The Fourier Transform in Chemistry. Part 1. Nuclear Magnetic Resonance: Introduction.

    ERIC Educational Resources Information Center

    King, Roy W.; Williams, Kathryn R.

    1989-01-01

    Using fourier transformation methods in nuclear magnetic resonance has made possible increased sensitivity in chemical analysis. This article describes these methods as they relate to magnetization, the RF magnetic field, nuclear relaxation, the RF pulse, and free induction decay. (CW)

  12. Unconventional nuclear magnetic resonance techniques using nanostructured diamond surfaces

    NASA Astrophysics Data System (ADS)

    Acosta, Victor; Jarmola, Andrey; Budker, Dmitry; Santori, Charles; Huang, Zhihong; Beausoleil, Raymond

    2014-03-01

    Nuclear magnetic resonance (NMR) technologies rely on obtaining high nuclear magnetization, motivating low operating temperatures and high magnetic fields. Dynamic nuclear polarization (DNP) techniques traditionally require another superconducting magnet and THz optics. We seek to use chip-scale devices to polarize nuclei in liquids at room temperature. The technique relies on optical pumping of nitrogen-vacancy (NV) centers and subsequent transfer of polarization to nuclei via hyperfine interaction, spin diffusion, and heteronuclear polarization transfer. We expect efficient polarization transfer will be realized by maximizing the diamond surface area. We have fabricated densely-packed (50 % packing fraction), high-aspect-ratio (10+) nanopillars over mm2 regions of the diamond surface. Pillars designed to have a few-hundred-nanometer diameter act as optical antennas, reducing saturation intensity. We also report progress in using nanopillar arrays as sensitive optical detectors of nano-scale NMR by measuring NV center Zeeman shifts produced by nearby external nuclei. The enhanced surface area increases the effective density of NV centers which couple to external nuclei. Combining these techniques may enable, e.g., identification of trace analytes and molecular imaging.

  13. Nuclear Level Density and gamma-ray Strength Function of 243Pu

    NASA Astrophysics Data System (ADS)

    Laplace, Thibault Andre

    The level density and gamma-ray strength function of 243Pu have been determined using the Oslo method. A 12 MeV deuteron beam from the University of Oslo cyclotron was used to populate excited states in the quasi-continuum of 243Pu using the 242Pu(d,p) reaction. The distribution of primary gamma-rays as function of the excitation energy has been extracted from particle-gamma coincidence data. Based on the Brink-Axel asumption that the primary gamma-ray spectrum is proportional to the product of the gamma-ray transmission coefficient (which only depends on the transition energy) times the level density at the excitation energy of the final state. The gamma-ray strength function is calculated from the gamma-ray transmission coefficient assuming pure dipole radiation. Both, the level density and gamma-ray strength function, are normalized using available experimental data from libraries. The level density of 243Pu follows closely the constant-temperature level density formula. An enhancement of the gamma-ray strength function is seen at low energies that is similar to that previously measured in other actinides. This structure is interpreted as the M1 scissors resonance. Its centroid o=2.42(5) MeV and its total strength B =10.1(15) mu N2 are in excellent agreement with sum-rule estimates. The measured level density and gamma-ray strength function were then used to calculate the 242Pu(n,gamma) cross section within the Hauser-Feshbach formalism.

  14. Nuclear quadrupole resonance studies of the SORC sequence and nuclear magnetic resonance studies of polymers

    SciTech Connect

    Jayakody, J.R.P.

    1993-12-31

    The behavior of induction signals during steady-state pulse irradiation in {sup 14}N NQR was investigated experimentally. Because Strong Off-resonance Comb (SORC) signals recur as long as the pulsing continues, very efficient signal-averaging can result. The dependence of these steady-state SORC signals on pulse parameters and on frequency offset are presented, together with a discussion of the applicability of the method. Also as part of the NQR work, cocaine base has been detected using conventional NQR techniques. The experimental results show that SORC detection can be of sufficient sensitivity to form the basis of narcotics screening devices for both mail and airline baggage. A new NMR technique, to obtain the correlation time of the random thermal motion of a polymer at temperatures near the glass transition has been introduced. The temperature dependence is a result of thermal motion. For slow-motion of a polymer chain near the glass transition, the CSA parameter begins to decrease. This motional narrowing can be interpreted to yield the correlation time of the thermal motion. In this work nitrocellulose isotopically highly enriched with {sup 15}N was studied at four different temperatures between 27{degrees} and 120{degrees} Celsius and the correlation times for polymer backbone motions were obtained. Naflon films containing water (D{sub 2}O and H{sub 2} {sup 17}O) and methanol (CH{sub 3}OD, CH{sub 3} {sup 17}OH), have been studied using deuteron and oxygen-17 NMR spectroscopy. Glassy behavior of the water domains at low temperature is evidenced by the specific nature of the {sup 2}H NMR lineshapes. Activation energies extracted from {sup 2}H spin-lattice relaxation data on the high temperature side of the T{sub 1} minimum exhibit a steady increase with increasing water content. In spite of a high degree of molecular mobility, angular-dependent spectra of both unstretched and stretched samples reflect considerable anisotrophy of the host polymer.

  15. Nuclear Magnetic Resonance Studies in Heavy Fermion Materials

    NASA Astrophysics Data System (ADS)

    Shirer, Kent Robert

    29Si, 31P, and 115In nuclear magnetic resonance studies of heavy fermion materials URu2Si 2, CeRhIn5, and URu2Si2- xPx were conducted as a function of temperature, pressure, and, in the case of URu2Si2- xPx, doping. Knight shift measurements in these systems probe the hybridization between conduction and local f-electrons which is described by the heavy fermion coherence temperature, T*, and can be captured by a two fluid model. This model takes the dual nature of the local moments and the heavy electron fluid into account. In URu2Si2 in a pressure range from 0-9.1 kbar, spin-lattice-relaxation data were taken and suggest a partial suppression of the density of states below 30 K. The data are analyzed in terms of a two component spin-fermion model. The spin-lattice-relaxation behavior is then compared to other materials that demonstrate precursor fluctuations in a pseudogap regime above a ground state with long-range order. Nuclear magnetic resonance data in CeRhIn5 for both the In(1) and In(2) sites are also taken under hydrostatic pressure. The Knight shift data reveal a suppression of the hyperfine coupling to the In(1) site as a function of pressure, and the electric field gradient at the In(2) site exhibits a change of slope. These changes to these coupling constants reflect alterations to the electronic structure at the quantum critical point. Finally, we report 31P nuclear magnetic resonance measurements in single crystals of URu2Si2-xP x with x = 0.09, 0.33. In the case of the x = 0.09 doping, we find no evidence for a phase transition, though the material still exhibits heavy fermion coherence. In the x = 0.33 doping, we find that it undergoes an antiferromagnetic (AFM) phase transition. When we include the pure compound in our analysis, we find that the hyperfine couplings and coherence temperatures evolve with doping. We compare this evolution with the trends seen in other compounds.

  16. The orphan nuclear receptor DAX-1 acts as a novel transcriptional corepressor of PPAR{gamma}

    SciTech Connect

    Kim, Gwang Sik; Lee, Gha Young; Nedumaran, Balachandar; Park, Yun-Yong; Kim, Kyung Tae; Park, Sang Chul; Lee, Young Chul; Kim, Jae Bum Choi, Hueng-Sik

    2008-05-30

    DAX-1 is an atypical nuclear receptor (NR) which functions primarily as a transcriptional corepressor of other NRs via heterodimerization. Peroxisome proliferator-activated receptor (PPAR) {gamma} is a ligand-dependent NR which performs a key function in adipogenesis. In this study, we evaluated a novel cross-talk mechanism between DAX-1 and PPAR{gamma}. Transient transfection assays demonstrated that DAX-1 inhibits the transactivity of PPAR{gamma} in a dose-dependent manner. DAX-1 directly competed with the PPAR{gamma} coactivator (PGC)-1{alpha} for binding to PPAR{gamma}. Endogenous levels of DAX-1 were significantly lower in differentiated 3T3-L1 adipocytes as compared to preadipocytes. Using a retroviral expression system, we demonstrated that DAX-1 overexpression downregulates the expression of PPAR{gamma} target genes, resulting in an attenuation of adipogenesis in 3T3-L1 cells. Our results suggest that DAX-1 acts as a corepressor of PPAR{gamma} and performs a potential function in the regulation of PPAR{gamma}-mediated cellular differentiation.

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

    SciTech Connect

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

    2016-05-15

    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 {sup 75}As, {sup 69}Ga and {sup 71}Ga, 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.

  18. A combined nuclear magnetic resonance and computational study of monohydroxyflavones applied to product ion mass spectra.

    PubMed

    Burns, Darcy C; Ellis, David A; Li, Hongxia; Lewars, Errol G; March, Raymond E

    2007-01-01

    A method is presented for the estimation of 13C-chemical shifts for carbon atoms in protonated and deprotonated molecules; in principle, this method can be applied to ions in general. Experimental 13C-chemical shifts were found to vary linearly with computed atomic charges using the PM3 method. Pseudo-13C-chemical shifts for atoms in protonated and deprotonated molecules can be estimated from computed atomic charges for such atoms using the above linear relationship. The pseudo-13C-chemical shifts obtained were applied to the rationalization of product ion mass spectra of protonated and deprotonated molecules of flavone and 3-, 5-, 6-, 7-, 2'-, 3'-, and 4'-hydroxyflavones, where product ion formation is due to either cross-ring cleavage of the C-ring (retro-Diels-Alder reaction) or to cleavage of a C-ring bond followed by loss of either a small neutral molecule or a radical. The total product ion abundance ratio of C-ring cross cleavage to C-ring bond cleavage, gamma, varied by a factor of 660 for deprotonated monohydroxyflavones, i.e., from 0.014:1 to 9.27:1. The magnitude of gamma, which is dependent on the relative bond orders within the C-ring of the protonated and deprotonated molecules of monohydroxyflavones, can be rationalized on the basis of the magnitudes of the 13C- and 1H-chemical shifts as determined by nuclear magnetic resonance spectroscopy.

  19. Investigating resonances above and below the threshold in nuclear reactions of astrophysical interest and beyond

    SciTech Connect

    La Cognata, M.; Kiss, G. G.; Mukhamedzhanov, A. M.; Spitaleri, C.; Trippella, O.

    2015-10-15

    Resonances in nuclear cross sections dramatically change their trends. Therefore, the presence of unexpected resonances might lead to unpredicted consequences on astrophysics and nuclear physics. In nuclear physics, resonances allow one to study states in the intermediate compound systems, to evaluate their cluster structure, for instance, especially in the energy regions approaching particle decay thresholds. In astrophysics, resonances might lead to changes in the nucleosynthesis flow, determining different isotopic compositions of the nuclear burning ashes. For these reasons, the Trojan Horse method has been modified to investigate resonant reactions. Thanks to this novel approach, for the first time normalization to direct data might be avoided. Moreover, in the case of sub threshold resonances, the Trojan Horse method modified to investigate resonances allows one to deduce the asymptotic normalization coefficient, showing the close connection between the two indirect approaches.

  20. Instructions for calibrating gamma detectors using the Canberra-Nuclear Data Genie Gamma Spectroscopy System

    SciTech Connect

    Brunk, J.L.

    1995-09-01

    A straight forward protocol provides a way to guide the calibration of a gamma detector for a particular geometry and material. Several programs have used the Low Level Gamma Counting Facility of the Health and Ecological Assessment Division of the Lawrence Livermore National Laboratory to count a variety of large environmental samples contained in several unique geometries. The equipment and calibration requirements needed to analyze these types of samples are explained. This document describes the calibration protocol that has been developed and describes how it is used to calibrate the detectors.

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

    SciTech Connect

    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. Phosphorus-31 nuclear magnetic resonance spectroscopy of toad retina.

    PubMed Central

    Apte, D V; Koutalos, Y; McFarlane, D K; Dawson, M J; Ebrey, T G

    1989-01-01

    Phosphorus-31 nuclear magnetic resonance (31P-NMR) spectra were obtained from living toad retinae and toad retinal extracts at 4 degrees C. Several phosphorus metabolites--nucleoside di- and triphosphates (NTP), phosphocreatine, phosphodiesters, inorganic phosphate, and phosphomonoesters--were identified from the spectra of whole retinae. The intracellular pH was determined to be 7.27 +/- 0.06 at 4 degrees C and the intracellular MgNTP/NTP ratio was at least 0.77. These results are consistent with those reported by other techniques, and they show that 31P-NMR spectroscopy can be used for noninvasively and quantitatively studying the metabolism of living toad retinae, and for monitoring its changes over time. PMID:2506940

  3. Optimal filtering in multipulse sequences for nuclear quadrupole resonance detection

    NASA Astrophysics Data System (ADS)

    Osokin, D. Ya.; Khusnutdinov, R. R.; Mozzhukhin, G. V.; Rameev, B. Z.

    2014-05-01

    The application of the multipulse sequences in nuclear quadrupole resonance (NQR) detection of explosive and narcotic substances has been studied. Various approaches to increase the signal to noise ratio (SNR) of signal detection are considered. We discussed two modifications of the phase-alternated multiple-pulse sequence (PAMS): the 180° pulse sequence with a preparatory pulse and the 90° pulse sequence. The advantages of optimal filtering to detect NQR in the case of the coherent steady-state precession have been analyzed. It has been shown that this technique is effective in filtering high-frequency and low-frequency noise and increasing the reliability of NQR detection. Our analysis also shows the PAMS with 180° pulses is more effective than PSL sequence from point of view of the application of optimal filtering procedure to the steady-state NQR signal.

  4. Blood species discrimination using proton nuclear magnetic resonance spectroscopy.

    PubMed

    Zailer, Elina; Diehl, Bernd W K; Monakhova, Yulia B

    2017-05-01

    Blood species identification is an important challenge in forensic science. Conventional methods used for blood species analysis are destructive and associated with time-consuming sample preparation steps. Nuclear magnetic resonance (NMR) spectroscopy is known for its nondestructive properties and fast results. This research study presents a proton ((1)H) NMR method to discriminate blood species including human, cat, dog, elephant, and bison. Characteristic signals acting as markers are observed for each species. Moreover, the data are evaluated by principle component analysis (PCA) and support vector machines (SVM). A 100% correct species recognition between human and nonhuman species is achieved using radial basis kernel function (RBF) and standardized data. The research study shows that (1)H NMR spectroscopy is a powerful tool for differentiating human and nonhuman blood showing a great significance to forensic science.

  5. Quantitative velocity distributions via nuclear magnetic resonance flow metering

    NASA Astrophysics Data System (ADS)

    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.

  6. Observation of superconductivity in hydrogen sulfide from nuclear resonant scattering.

    PubMed

    Troyan, Ivan; Gavriliuk, Alexander; Rüffer, Rudolf; Chumakov, Alexander; Mironovich, Anna; Lyubutin, Igor; Perekalin, Dmitry; Drozdov, Alexander P; Eremets, Mikhail I

    2016-03-18

    High-temperature superconductivity remains a focus of experimental and theoretical research. Hydrogen sulfide (H2S) has been reported to be superconducting at high pressures and with a high transition temperature. We report on the direct observation of the expulsion of the magnetic field in H2S compressed to 153 gigapascals. A thin (119)Sn film placed inside the H2S sample was used as a sensor of the magnetic field. The magnetic field on the (119)Sn sensor was monitored by nuclear resonance scattering of synchrotron radiation. Our results demonstrate that an external static magnetic field of about 0.7 tesla is expelled from the volume of (119)Sn foil as a result of the shielding by the H2S sample at temperatures between 4.7 K and approximately 140 K, revealing a superconducting state of H2S.

  7. First principles nuclear magnetic resonance signatures of graphene oxide.

    PubMed

    Lu, Ning; Huang, Ying; Li, Hai-bei; Li, Zhenyu; Yang, Jinlong

    2010-07-21

    Nuclear magnetic resonance (NMR) has been widely used in graphene oxide (GO) structure studies. However, the detailed relationship between its spectroscopic features and the GO structural configuration remains elusive. Based on first principles (13)C chemical shift calculations using the gauge including projector augmented waves method, we provide a reliable spectrum-structure connection. The (13)C chemical shift in GO is found to be very sensitive to the atomic environment, even for the same type of oxidation groups. Factors determining the chemical shifts of epoxy and hydroxy groups have been discussed. GO structures previously reported in the literature have been checked from the NMR point of view. The energetically favorable hydroxy chain structure is not expected to be widely existed in real GO samples according to our NMR simulations. The epoxy pair species we proposed previously is also supported by chemical shift calculations.

  8. First principles nuclear magnetic resonance signatures of graphene oxide

    NASA Astrophysics Data System (ADS)

    Lu, Ning; Huang, Ying; Li, Hai-bei; Li, Zhenyu; Yang, Jinlong

    2010-07-01

    Nuclear magnetic resonance (NMR) has been widely used in graphene oxide (GO) structure studies. However, the detailed relationship between its spectroscopic features and the GO structural configuration remains elusive. Based on first principles C13 chemical shift calculations using the gauge including projector augmented waves method, we provide a reliable spectrum-structure connection. The C13 chemical shift in GO is found to be very sensitive to the atomic environment, even for the same type of oxidation groups. Factors determining the chemical shifts of epoxy and hydroxy groups have been discussed. GO structures previously reported in the literature have been checked from the NMR point of view. The energetically favorable hydroxy chain structure is not expected to be widely existed in real GO samples according to our NMR simulations. The epoxy pair species we proposed previously is also supported by chemical shift calculations.

  9. Applications of nuclear magnetic resonance imaging in process engineering

    NASA Astrophysics Data System (ADS)

    Gladden, Lynn F.; Alexander, Paul

    1996-03-01

    During the past decade, the application of nuclear magnetic resonance (NMR) imaging techniques to problems of relevance to the process industries has been identified. The particular strengths of NMR techniques are their ability to distinguish between different chemical species and to yield information simultaneously on the structure, concentration distribution and flow processes occurring within a given process unit. In this paper, examples of specific applications in the areas of materials and food processing, transport in reactors and two-phase flow are discussed. One specific study, that of the internal structure of a packed column, is considered in detail. This example is reported to illustrate the extent of new, quantitative information of generic importance to many processing operations that can be obtained using NMR imaging in combination with image analysis.

  10. Nuclear magnetic resonance of iron and copper disease states

    SciTech Connect

    Runge, V.M.; Clanton, J.A.; Smith, F.W.; Hutchison, J.; Mallard, J.; Partain, C.L.; James, A.E. Jr.

    1983-11-01

    The tissue levels of paramagnetic ions are an important factor in the determination of T/sub 1/ values as observed by nuclear magnetic resonance (NMR) imaging. The increased levels of iron present in human disease states such as hemochromatosis lead to decreased T/sub 1/ values. The mean liver T/sub 1/ of three patients with iron storage disease was determined to be 130 msec, significantly different from the value of 154 msec, the mean for 14 normal controls. Whether NMR will be able to detect the increased copper levels in liver and brain in Wilson disease remains for further clinical trials to evaluate. NMR imaging, however, does serve as a noninvasive method for the diagnosis of states of iron overload and as a technique to follow progression of disease or response to medical therapy.

  11. Microwave-free nuclear magnetic resonance at molecular scales

    NASA Astrophysics Data System (ADS)

    Wood, James D. A.; Tetienne, Jean-Philippe; Broadway, David A.; Hall, Liam T.; Simpson, David A.; Stacey, Alastair; Hollenberg, Lloyd C. L.

    2017-07-01

    The implementation of nuclear magnetic resonance (NMR) at the nanoscale is a major challenge, as the resolution of conventional methods is limited to mesoscopic scales. Approaches based on quantum spin probes, such as the nitrogen-vacancy (NV) centre in diamond, have achieved nano-NMR under ambient conditions. However, the measurement protocols require application of complex microwave pulse sequences of high precision and relatively high power, placing limitations on the design and scalability of these techniques. Here we demonstrate NMR on a nanoscale organic environment of proton spins using the NV centre while eliminating the need for microwave manipulation of either the NV or the environmental spin states. We also show that the sensitivity of our significantly simplified approach matches that of existing techniques using the NV centre. Removing the requirement for coherent manipulation while maintaining measurement sensitivity represents a significant step towards the development of robust, non-invasive nanoscale NMR probes.

  12. Serum metabonomics of acute leukemia using nuclear magnetic resonance spectroscopy

    PubMed Central

    Musharraf, Syed Ghulam; Siddiqui, Amna Jabbar; Shamsi, Tahir; Choudhary, M. Iqbal; Rahman, Atta-ur

    2016-01-01

    Acute leukemia is a critical neoplasm of white blood cells. In order to differentiate between the metabolic alterations associated with two subtypes of acute leukemia, acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML), we investigated the serum of ALL and AML patients and compared with two controls (healthy and aplastic anemia) using 1H NMR (nuclear magnetic resonance) spectroscopy. Thirty-seven putative metabolites were identified using Carr-Purcell-Meiboom-Gill (CPMG) sequence. The use of PLS-DA and OPLS-DA models gave results with 84.38% and 90.63% classification rate, respectively. The metabolites responsible for classification are mainly lipids, lactate and glucose. Compared with controls, ALL and AML patients showed serum metabonomic differences involving aberrant metabolism pathways including glycolysis, TCA cycle, lipoprotein changes, choline and fatty acid metabolisms. PMID:27480133

  13. Microwave-free nuclear magnetic resonance at molecular scales.

    PubMed

    Wood, James D A; Tetienne, Jean-Philippe; Broadway, David A; Hall, Liam T; Simpson, David A; Stacey, Alastair; Hollenberg, Lloyd C L

    2017-07-03

    The implementation of nuclear magnetic resonance (NMR) at the nanoscale is a major challenge, as the resolution of conventional methods is limited to mesoscopic scales. Approaches based on quantum spin probes, such as the nitrogen-vacancy (NV) centre in diamond, have achieved nano-NMR under ambient conditions. However, the measurement protocols require application of complex microwave pulse sequences of high precision and relatively high power, placing limitations on the design and scalability of these techniques. Here we demonstrate NMR on a nanoscale organic environment of proton spins using the NV centre while eliminating the need for microwave manipulation of either the NV or the environmental spin states. We also show that the sensitivity of our significantly simplified approach matches that of existing techniques using the NV centre. Removing the requirement for coherent manipulation while maintaining measurement sensitivity represents a significant step towards the development of robust, non-invasive nanoscale NMR probes.

  14. Microwave-free nuclear magnetic resonance at molecular scales

    PubMed Central

    Wood, James D. A.; Tetienne, Jean-Philippe; Broadway, David A.; Hall, Liam T.; Simpson, David A.; Stacey, Alastair

    2017-01-01

    The implementation of nuclear magnetic resonance (NMR) at the nanoscale is a major challenge, as the resolution of conventional methods is limited to mesoscopic scales. Approaches based on quantum spin probes, such as the nitrogen-vacancy (NV) centre in diamond, have achieved nano-NMR under ambient conditions. However, the measurement protocols require application of complex microwave pulse sequences of high precision and relatively high power, placing limitations on the design and scalability of these techniques. Here we demonstrate NMR on a nanoscale organic environment of proton spins using the NV centre while eliminating the need for microwave manipulation of either the NV or the environmental spin states. We also show that the sensitivity of our significantly simplified approach matches that of existing techniques using the NV centre. Removing the requirement for coherent manipulation while maintaining measurement sensitivity represents a significant step towards the development of robust, non-invasive nanoscale NMR probes. PMID:28671183

  15. Nuclear magnetic resonance spectral analysis and molecular properties of berberine

    NASA Astrophysics Data System (ADS)

    Huang, Ming-Ju; Lee, Ken S.; Hurley, Sharon J.

    An extensive theoretical study of berberine has been performed at the ab initio HF/6-31G**, HF/6-311G**, and B3LYP/6-311G** levels with and without solvent effects. The optimized structures are compared with X-ray data. We found that the optimized structures with solvent effects are in slightly better agreement with X-ray data than those without solvent effects. The 1H and 13C nuclear magnetic resonance (NMR) chemical shifts of berberine were calculated by using the gauge-independent atomic orbital (GIAO) (with and without solvent effects), CSGT, and IGAIM methods. The calculated chemical shifts were compared with the two-dimensional NMR experimental data. Overall, the calculated chemical shifts show very good agreement with the experimental results. The harmonic vibrational frequencies for berberine were calculated at the B3LYP/6-311G** level.

  16. Mixed radiation field dosimetry utilizing Nuclear Quadrupole Resonance

    SciTech Connect

    Hintenlang, D.

    1991-01-01

    This project has proposed to develop a novel dosimetry system that is capable of directly evaluating the chemical/biological damage caused by neutrons, photons, or both in a single measurement. The dosimeter itself will consist of a small volume of biological equivalent material that is probed for radiation damage with Nuclear Quadrupole Resonance (NQR) techniques. NQR has previously been utilized as a sensitive probe of structural and chemical changes at the molecular level for a variety of organic compounds. The biological equivalent materials used in this study will not only have a density similar to tissue (tissue equivalent) but will have the same atomic components as tissue. This is a significant requirement if the important neutron interactions that occur in tissue are to occur in the dosimeter as well. The overall objective of this study is to investigate a methodology to perform accurate mixed-field (neutron and photon) dosimetry for biological systems.

  17. Nuclear quadrupole resonance studies of amorphous, orthorhombic, and rhombohedral arsenic

    SciTech Connect

    Jellison, G.E. Jr.; Petersen, G.L.; Taylor, P.C.

    1980-10-15

    Pulsed nuclear quadrupole resonance (NQR) experiments have been performed on three forms of elemental arsenic: amorphous (a), rhombohedral (rh), and orthorhombic (or). The temperature dependence of the spin-lattice relaxation time (T/sub 1/) provides evidence for the existence of disorder (tunneling) modes in a-As. It is found that the NQR line shape of a-As is highly asymmetric, and this asymmetry is attributed to a distribution of dihedral angles in a-As. The observed NQR frequencies indicate that the amount of bonding s admixture is different in each material (rh-As:3%, or-As:7%, a-As:10%). Simple calculations in comparison with x-ray results indicate that the bonding configurations in these three forms of arsenic do not necessarily correspond to maximum overlap of bonding orbitals on adjacent atoms.

  18. State interrogation in nuclear magnetic resonance quantum-information processing

    SciTech Connect

    Leskowitz, Garett M.; Mueller, Leonard J.

    2004-05-01

    Reconstruction of a reduced density operator for weakly coupled systems of spins (1/2) from fits to nuclear magnetic resonance spectra is described in detail. Particular emphasis is placed on data treatment procedures that specify fewer than the 3{sup n} complete spectra that are implicitly prescribed in published references to state tomography on n-spin systems. It is shown that if the density operator is expanded in the so-called product-operator basis, it is always possible to estimate a desired coefficient in the expansion by measuring a single spectral multiplet. This simple observation can substantially reduce the experimental effort required for either complete density-matrix reconstruction or estimation of subsets of the coefficients in the product-operator expansion. A simple iterative algorithm can be used to produce reduced measurement procedures for experiments involving small numbers of qubits.

  19. Nuclear magnetic resonance imaging of induced renal lesions

    SciTech Connect

    London, D.A.; Davis, P.L.; Williams, R.D.; Crooks, L.E.; Sheldon, P.E.; Gooding, C.A.

    1983-07-01

    Nuclear magnetic resonance (NMR) images obtained after unilateral ligation of the ureter, renal artery, or renal vein in the rat were analyzed and compared with NMR images of the normal rat kidney. Anatomic and functional correlation of the induced renal lesions was made by concurrent CT and by gross examination of the excised kidneys. Many normal anatomic structures at the level of the renal hilum can be identified by high resolution NMR imaging. Differentiation of urine from renal parenchyma permits detection of gross changes both in renal function and in the mass of the renal parenchyma. NMR imaging is capable of diagnosing hydronephrosis, acute renal ischemia, and acute venous congestion in this rat model. In addition, a trend toward prolongation of the relaxation times T1 and T2 for abnormal renal parenchyma is demonstrated.

  20. Nuclear quadrupole resonance study of hydrogen bonded solid materials.

    PubMed

    Seliger, Janez

    2011-09-01

    Nuclear quadrupole resonance is presented as a method for the study of solid hydrogen bonded materials. NQR study of hydrogen bonds in ferroelectric and paraelectric KH2PO4, antiferroelectric and paraelectric squaric acid, ferroelectric croconic acid and antiferroelectric and paraelectric cocrystal 5'-dimethyl-2, 2'-bipyridine - chloranilic acid (1:1) are discussed in more details. A 14N NQR study of the strong short O-HKN hydrogen bond in two polymorphic forms of cocrystal isonicotinamide-oxalic acid (2:1) is presented as well. Various correlations between the NQR parameters and between the NQR and structural parameters have been observed. These correlations may be used to determine the proton position in a hydrogen bond and some other structural parameters from the NQR data.

  1. Some applications of gamma absorptiometry and spectrometry for the control of nuclear materials

    NASA Astrophysics Data System (ADS)

    Guery, M.

    1991-02-01

    In nuclear fuels, and neutrons absorbers used in control rods, the thermal power generated is locally dependent on the concentration of the fissile or absorbing nucleus. In order to control the homogeneity of such materials, non-destructive methods using either gamma absorptiometry or gamma spectrometry were developed; some applications of these methods are presented in this paper. The fuel of the High Temperature Reactor (HTR) is frequently composed of UO 2 and ThO 2 spherical particles dispersed in a carbon matrix; the axial distribution of the particles along the fuel rods can be controlled in two ways: with gamma absorptiometry the heavy elements atoms (U+Th) can be detected but without discrimination between U and Th; with gamma spectrometry, separate distributions of uranium and thorium, deduced from the intensity of characteristic gamma rays are obtained. In nuclear power plants (PWR, FBR) the control rods are made usually with boron carbide (B 4C) pellets. By mean of gamma absorptiometry scanning the density distribution along the axis and the radius of the pellets are obtained. The originality of the method consists in the use of a self-calibration process, then the knowledge of the mass absorption coefficient is not required to perform the examinations. A computerized apparatus has been developed for these controls.

  2. Nuclear magnetic resonance experiments with dc SQUID amplifiers

    SciTech Connect

    Heaney, M.B. . Dept. of Physics Lawrence Berkeley Lab., CA )

    1990-11-01

    The development and fabrication of dc SQUIDs (Superconducting QUantum Interference Devices) with Nb/Al{sub 2}O{sub 3}/Nb Josephson junctions is described. A theory of the dc SQUID as a radio-frequency amplifier is presented, with an optimization strategy that accounts for the loading and noise contributions of the postamplifier and maximizes the signal-to-noise ratio of the total system. The high sensitivity of the dc SQUID is extended to high field NMR. A dc SQUID is used as a tuned radio-frequency amplifier to detect pulsed nuclear magnetic resonance at 32 MHz from a metal film in a 3.5 Tesla static field. A total system noise temperature of 11 K has been achieved, at a bath temperature of 4.2 K. The minimum number of nuclear Bohr magnetons observable from a free precession signal after a single pulse is about 2 {times} 10{sup 17} in a bandwidth of 25 kHz. In a separate experiment, a dc SQUID is used as a rf amplifier in a NQR experiment to observe a new resonance response mechanism. The net electric polarization of a NaClO{sub 3} crystal due to the precessing electric quadrupole moments of the Cl nuclei is detected at 30 MHz. The sensitivity of NMR and NQR spectrometers using dc SQUID amplifiers is compared to the sensitivity of spectrometers using conventional rf amplifiers. A SQUID-based spectrometer has a voltage sensitivity which is comparable to the best achieved by a FET-based spectrometer, at these temperatures and operating frequencies.

  3. /sup 13/C nuclear magnetic resonance studies of cardiac metabolism

    SciTech Connect

    Seeholzer, S.H.

    1985-01-01

    The last decade has witnessed the increasing use of Nuclear Magnetic Resonance (NMR) techniques for following the metabolic fate of compounds specifically labeled with /sup 13/C. The goals of the present study are: (1) to develop reliable quantitative procedures for measuring the /sup 13/C enrichment of specific carbon sites in compounds enriched by the metabolism of /sup 13/C-labeled substrates in rat heart, and (2) to use these quantitative measurements of fractional /sup 13/C enrichment within the context of a mathematical flux model describing the carbon flow through the TCA cycle and ancillary pathways, as a means for obtaining unknown flux parameters. Rat hearts have been perfused in vitro with various combinations of glucose, acetate, pyruvate, and propionate to achieve steady state flux conditions, followed by perfusion with the same substrates labeled with /sup 13/C in specific carbon sites. The hearts were frozen at different times after addition of /sup 13/C-labeled substrates and neutralized perchloric acid extracts were used to obtain high resolution proton-decoupled /sup 13/C NMR spectra at 90.55 MHz. The fractional /sup 13/C enrichment (F.E.) of individual carbon sites in different metabolites was calculated from the area of the resolved resonances after correction for saturation and nuclear Overhauser effects. These F.E. measurements by /sup 13/C NMR were validated by the analysis of /sup 13/C-/sup 1/H scalar coupling patterns observed in /sup 1/H NMR spectra of the extracted metabolites. The results obtained from perfusion of hearts glucose plus either (2-/sup 13/C) acetate or (3-/sup 13/C) pyruvate are similar to those obtained by previous investigators using /sup 14/C-labeled substrates.

  4. Nuclear photonics

    SciTech Connect

    Habs, D.; Guenther, M. M.; Jentschel, M.; Thirolf, P. G.

    2012-07-09

    With the planned new {gamma}-beam facilities like MEGa-ray at LLNL (USA) or ELI-NP at Bucharest (Romania) with 10{sup 13}{gamma}/s and a band width of {Delta}E{gamma}/E{gamma} Almost-Equal-To 10{sup -3}, a new era of {gamma} beams with energies up to 20MeV comes into operation, compared to the present world-leading HI{gamma}S facility at Duke University (USA) with 10{sup 8}{gamma}/s and {Delta}E{gamma}/E{gamma} Almost-Equal-To 3 Dot-Operator 10{sup -2}. In the long run even a seeded quantum FEL for {gamma} beams may become possible, with much higher brilliance and spectral flux. At the same time new exciting possibilities open up for focused {gamma} beams. Here we describe a new experiment at the {gamma} beam of the ILL reactor (Grenoble, France), where we observed for the first time that the index of refraction for {gamma} beams is determined by virtual pair creation. Using a combination of refractive and reflective optics, efficient monochromators for {gamma} beams are being developed. Thus, we have to optimize the total system: the {gamma}-beam facility, the {gamma}-beam optics and {gamma} detectors. We can trade {gamma} intensity for band width, going down to {Delta}E{gamma}/E{gamma} Almost-Equal-To 10{sup -6} and address individual nuclear levels. The term 'nuclear photonics' stresses the importance of nuclear applications. We can address with {gamma}-beams individual nuclear isotopes and not just elements like with X-ray beams. Compared to X rays, {gamma} beams can penetrate much deeper into big samples like radioactive waste barrels, motors or batteries. We can perform tomography and microscopy studies by focusing down to {mu}m resolution using Nuclear Resonance Fluorescence (NRF) for detection with eV resolution and high spatial resolution at the same time. We discuss the dominating M1 and E1 excitations like the scissors mode, two-phonon quadrupole octupole excitations, pygmy dipole excitations or giant dipole excitations under the new facet of

  5. Gamma-ray cascade transitions from resonant neutron capture in Cd-111 and Cd-113

    SciTech Connect

    Rusev, Gencho Y.

    2012-08-27

    A neutron-capture experiment on {sup nat}Cd has been carried out at DANCE. Multiple-fold coincidence {gamma}-ray spectra have been collected from J=0, 1 resonances in {sup 111}Cd and {sup 113}Cd. The cascades ending at the ground state can be described by the SLO model while the cascades ending at the 2+ states are better reproduced by the mixed SLO+KMF model.

  6. A Rotating Phantom: Evaluation Of Hard And Software For Gated Gamma Camera Systems In Nuclear Medicine.

    NASA Astrophysics Data System (ADS)

    Vanregemorter, J.; Deconinck, F.; Bossuyt, A.

    1986-06-01

    In this paper we describe a rotating dynamic phantom which allows quality control of hardware and software for gated gamma camera systems in nuclear medicine. The phantom not only allows simulation of a gated heart study but also testing of the response of the whole system to time frequencies.

  7. A personal computer-based nuclear magnetic resonance spectrometer

    NASA Astrophysics Data System (ADS)

    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.

  8. Frequency selective detection of nuclear quadrupole resonance (NQR) spin echoes

    NASA Astrophysics Data System (ADS)

    Somasundaram, Samuel D.; Jakobsson, Andreas; Smith, John A. S.; Althoefer, Kaspar A.

    2006-05-01

    Nuclear Quadrupole Resonance (NQR) is a radio frequency (RF) technique that can be used to detect the presence of quadrupolar nuclei, such as the 14N nucleus prevalent in many explosives and narcotics. The technique has been hampered by low signal-to-noise ratios and is further aggravated by the presence of RF interference (RFI). To ensure accurate detection, proposed detectors should exploit the rich form of the NQR signal. Furthermore, the detectors should also be robust to any remaining residual interference, left after suitable RFI mitigation has been employed. In this paper, we propose a new NQR data model, particularly for the realistic case where multiple pulse sequences are used to generate trains of spin echoes. Furthermore, we refine two recently proposed approximative maximum likelihood (AML) detectors, enabling the algorithm to optimally exploit the data model of the entire echo train and also incorporate knowledge of the temperature dependent spin-echo decay time. The AML-based detectors ensure accurate detection and robustness against residual RFI, even when the temperature of the sample is not precisely known, by exploiting the dependencies of the NQR resonant lines on temperature. Further robustness against residual interference is gained as the proposed detector is frequency selective; exploiting only those regions of the spectrum where the NQR signal is expected. Extensive numerical evaluations based on both simulated and measured NQR data indicate that the proposed Frequency selective Echo Train AML (FETAML) detector offers a significant improvement as compared to other existing detectors.

  9. Nuclear magnetic resonance probes of membrane biophysics: Structure and dynamics

    NASA Astrophysics Data System (ADS)

    Leftin, Avigdor

    The phospholipid membrane is a self-assembled, dynamic molecular system that may exist alone in association with only water, or in complex systems comprised of multiple lipid types and proteins. In this dissertation the intra- and inter-molecular forces responsible for the atomistic, molecular and collective equilibrium structure and dynamics are studied by nuclear magnetic resonance spectroscopy (NMR). The multinuclear NMR measurements and various experimental techniques are able to provide data that enable the characterization of the hierarchical spatio-temporal organization of the phospholipid membrane. The experimental and theoretical studies conducted target membrane interactions ranging from model systems composed of only water and lipids, to multiple component domain forming membranes that are in association with peripheral and trans-membrane proteins. These measurements consisit of frequency spectrum lineshapes and nuclear-spin relaxation rates obtained using 2H NMR, 13C NMR, 31P NMR and 1H NMR. The changes of these experimental observables are interpreted within a statistical thermodynamic framework that allows the membrane structure, activation energies, and correlation times of motion to be determined. The cases presented demonstrate how fundamental principles of NMR spectroscopy may be applied to a host of membranes, leading to the biophysical characterization of membrane structure and dynamics.

  10. Detecting special nuclear materials in containers using high-energy gamma rays emitted by fission products

    DOEpatents

    Norman, Eric B.; Prussin, Stanley G.

    2007-10-02

    A method and a system for detecting the presence of special nuclear materials in a container. The system and its method include irradiating the container with an energetic beam, so as to induce a fission in the special nuclear materials, detecting the gamma rays that are emitted from the fission products formed by the fission, to produce a detector signal, comparing the detector signal with a threshold value to form a comparison, and detecting the presence of the special nuclear materials using the comparison.

  11. Inverse Compton gamma-ray source for nuclear physics and related applications at the Duke FEL

    SciTech Connect

    O`Shea, P.G.; Litvinenko, V.N.; Madey, J.M.J.

    1995-12-31

    In recent years the development of intense, short-wavelength FEL light sources has opened opportunities for the development new applications of high-energy Compton-backscattered photons. These applications range from medical imaging with X-ray photons to high-energy physics with {gamma}{gamma} colliders. In this paper we discuss the possibilities for nuclear physics studies using polarized Compton backscattered {gamma}-rays from the Duke storage-ring-driven UV-FEL. There are currently a number of projects that produce polarized {gamma}-rays for nuclear physics studies. All of these facilities operate by scattering conventional laser-light against electrons circulating in a storage ring. In our scheme, intra-cavity scattering of the UV-FEL light will produce a {gamma}-flux enhancement of approximately 10{sup 3} over existing sources. The Duke ring can operate at energies up to 1.2 GeV and can produce FEL photons up to 12.5 eV. We plan to generate {gamma}-rays up to 200 MeV in energy with an average flux in excess of 10{sup 7} /s/MeV, using a modest scattering beam of 10-mA average stored current. The {gamma}-ray energy may be tuned by varying the FEL wavelength or by adjusting the stored electron beam energy. Because of the intense flux, we can eliminate the need for photon energy tagging by collimating of the {gamma}-ray beam. We will discuss the characteristics of the device and its research opportunities.

  12. Controlling nuclear JAKs and STATs for specific gene activation by IFN{gamma}

    SciTech Connect

    Noon-Song, Ezra N.; Ahmed, Chulbul M.; Dabelic, Rea; Canton, Johnathan; Johnson, Howard M.

    2011-07-08

    Highlights: {yields} Gamma interferon (IFN{gamma}) and its receptor subunit, IFNGR1, interact with the promoter region of IFN{gamma}-associated genes along with transcription factor STAT1{alpha}. {yields} We show that activated Janus kinases pJAK2 and pJAK1 also associate with IFNGR1 in the nucleus. {yields} The activated Janus kinases are responsible for phosphorylation of tyrosine 41 on histone H3, an important epigenetic event for specific gene activation. -- Abstract: We previously showed that gamma interferon (IFN{gamma}) and its receptor subunit, IFNGR1, interacted with the promoter region of IFN{gamma}-activated genes along with transcription factor STAT1{alpha}. Recent studies have suggested that activated Janus kinases pJAK2 and pJAK1 also played a role in gene activation by phosphorylation of histone H3 on tyrosine 41. This study addresses the question of the role of activated JAKs in specific gene activation by IFN{gamma}. We carried out chromatin immunoprecipitation (ChIP) followed by PCR in IFN{gamma} treated WISH cells and showed association of pJAK1, pJAK2, IFNGR1, and STAT1 on the same DNA sequence of the IRF-1 gene promoter. The {beta}-actin gene, which is not activated by IFN{gamma}, did not show this association. The movement of activated JAK to the nucleus and the IRF-1 promoter was confirmed by the combination of nuclear fractionation, confocal microscopy and DNA precipitation analysis using the biotinylated GAS promoter. Activated JAKs in the nucleus was associated with phosphorylated tyrosine 41 on histone H3 in the region of the GAS promoter. Unphosphorylated JAK2 was found to be constitutively present in the nucleus and was capable of undergoing activation in IFN{gamma} treated cells, most likely via nuclear IFNGR1. Association of pJAK2 and IFNGR1 with histone H3 in IFN{gamma} treated cells was demonstrated by histone H3 immunoprecipitation. Unphosphorylated STAT1 protein was associated with histone H3 of untreated cells. IFN{gamma

  13. Characterization of borate glasses by W-band pulse electron-nuclear double resonance spectroscopy

    SciTech Connect

    Kordas, George; Goldfarb, Daniella

    2008-10-21

    (100-x) mol % B{sub 2}O{sub 3} x mol %Me{sub 2}O (Me=Li,Na,K) glasses, exposed to {gamma}-{sup 60}Co irradiation to produce paramagnetic states, were characterized by W-band (95 GHz) pulse electron-nuclear double resonance (ENDOR) spectroscopy in order to characterize local structures occurring in the range of compositions between x=16 and x=25 at which the 'boron oxide' anomaly occurs. The high resolution of nuclear frequencies allowed resolving the {sup 7}Li and {sup 11}B ENDOR lines. In the samples with x=16 and x=20 glasses, {sup 11}B hyperfine couplings of 16, 24, and 36 MHz were observed and attributed to the tetraborate, triborate, and boron oxygen hole center (BOHC) structures, respectively. The x=25 samples showed hyperfine couplings of 15 MHz for the tetraborate and 36 MHz for BOHC. Density functional theory (DFT) calculations predicted for these structures negative hyperfine couplings, which were confirmed by W-band ENDOR. This suggests that a spin polarization mechanism accounts for the negative hyperfine structure splitting.

  14. [Effect of gamma-radiation and mitochondrial apoptogenic factors on nuclear protease activity].

    PubMed

    Kutsyĭ, M P; Kuznetsova, E A; Gluiaeva, N A; Gaziev, A I

    2002-01-01

    An increase in protease activity was shown in thymus nuclei of rats exposed to gamma-radiation. The activation of histone-specific proteases depended on the duration of postradiation period. Also, it was revealed that incubation of thymus nuclear with the intermembrane fraction of liver mitochondria caused degradation of histones and nonhistone nuclear proteins, as well as internucleosomal fragmentation of DNA. Simultaneously, nuclear proteases tightly bound to histones and specifically cleaving histones were observed to be activated by apoptogenic factors of the mitochondrial intermembrane fraction. Probably, the apoptogenic action of gamma-radiation involves not only a direct DNA damage that induces activation of DNA-dependent proteases but also an indirect component: destructive alterations in mitochondria leading to the exit of apoptogenic factors from the intermembrane space.

  15. Establishment of Imaging Spectroscopy of Nuclear Gamma-Rays based on Geometrical Optics

    NASA Astrophysics Data System (ADS)

    Tanimori, Toru; Mizumura, Yoshitaka; Takada, Atsushi; Miyamoto, Shohei; Takemura, Taito; Kishimoto, Tetsuro; Komura, Shotaro; Kubo, Hidetoshi; Kurosawa, Shunsuke; Matsuoka, Yoshihiro; Miuchi, Kentaro; Mizumoto, Tetsuya; Nakamasu, Yuma; Nakamura, Kiseki; Parker, Joseph D.; Sawano, Tatsuya; Sonoda, Shinya; Tomono, Dai; Yoshikawa, Kei

    2017-02-01

    Since the discovery of nuclear gamma-rays, its imaging has been limited to pseudo imaging, such as Compton Camera (CC) and coded mask. Pseudo imaging does not keep physical information (intensity, or brightness in Optics) along a ray, and thus is capable of no more than qualitative imaging of bright objects. To attain quantitative imaging, cameras that realize geometrical optics is essential, which would be, for nuclear MeV gammas, only possible via complete reconstruction of the Compton process. Recently we have revealed that “Electron Tracking Compton Camera” (ETCC) provides a well-defined Point Spread Function (PSF). The information of an incoming gamma is kept along a ray with the PSF and that is equivalent to geometrical optics. Here we present an imaging-spectroscopic measurement with the ETCC. Our results highlight the intrinsic difficulty with CCs in performing accurate imaging, and show that the ETCC surmounts this problem. The imaging capability also helps the ETCC suppress the noise level dramatically by ~3 orders of magnitude without a shielding structure. Furthermore, full reconstruction of Compton process with the ETCC provides spectra free of Compton edges. These results mark the first proper imaging of nuclear gammas based on the genuine geometrical optics.

  16. FIGARO : detecting nuclear materials using high-energy gamma rays for oxygen.

    SciTech Connect

    Michlich, B. J.; Smith, D. L.; Massey, T. N.; Ingram, D.; Fessler, A.

    2000-10-10

    Potential diversion of nuclear materials is a major international concern. Fissile (e.g., U, Pu) and other nuclear materials (e.g., D, Be) can be detected using 6-7 MeV gamma rays produced in the {sup 19}F(p,{alpha}{gamma}){sup 16}O reaction. These gamma rays will induce neutron emission via the photoneutron and photofission processes in nuclear materials. However, they are not energetic enough to generate significant numbers of neutrons from most common benign materials, thereby reducing the false alarm rate. Neutrons are counted using an array of BF3 counters in a polyethylene moderator. Experiments have shown a strong increase in neutron count rates for depleted uranium, Be, D{sub 2}O, and {sup 6}Li, and little or no increase for other materials (e.g., H{sub 2}O, SS, Cu, Al, C, {sup 7}Li). Gamma source measurements using solid targets of CaF{sub 2} and MgF{sub 2} and a SF{sub 6} gas target show that proton accelerator of 3 MeV and 10-100 microampere average current could lead to acceptable detection sensitivity.

  17. Establishment of Imaging Spectroscopy of Nuclear Gamma-Rays based on Geometrical Optics.

    PubMed

    Tanimori, Toru; Mizumura, Yoshitaka; Takada, Atsushi; Miyamoto, Shohei; Takemura, Taito; Kishimoto, Tetsuro; Komura, Shotaro; Kubo, Hidetoshi; Kurosawa, Shunsuke; Matsuoka, Yoshihiro; Miuchi, Kentaro; Mizumoto, Tetsuya; Nakamasu, Yuma; Nakamura, Kiseki; Parker, Joseph D; Sawano, Tatsuya; Sonoda, Shinya; Tomono, Dai; Yoshikawa, Kei

    2017-02-03

    Since the discovery of nuclear gamma-rays, its imaging has been limited to pseudo imaging, such as Compton Camera (CC) and coded mask. Pseudo imaging does not keep physical information (intensity, or brightness in Optics) along a ray, and thus is capable of no more than qualitative imaging of bright objects. To attain quantitative imaging, cameras that realize geometrical optics is essential, which would be, for nuclear MeV gammas, only possible via complete reconstruction of the Compton process. Recently we have revealed that "Electron Tracking Compton Camera" (ETCC) provides a well-defined Point Spread Function (PSF). The information of an incoming gamma is kept along a ray with the PSF and that is equivalent to geometrical optics. Here we present an imaging-spectroscopic measurement with the ETCC. Our results highlight the intrinsic difficulty with CCs in performing accurate imaging, and show that the ETCC surmounts this problem. The imaging capability also helps the ETCC suppress the noise level dramatically by ~3 orders of magnitude without a shielding structure. Furthermore, full reconstruction of Compton process with the ETCC provides spectra free of Compton edges. These results mark the first proper imaging of nuclear gammas based on the genuine geometrical optics.

  18. Establishment of Imaging Spectroscopy of Nuclear Gamma-Rays based on Geometrical Optics

    PubMed Central

    Tanimori, Toru; Mizumura, Yoshitaka; Takada, Atsushi; Miyamoto, Shohei; Takemura, Taito; Kishimoto, Tetsuro; Komura, Shotaro; Kubo, Hidetoshi; Kurosawa, Shunsuke; Matsuoka, Yoshihiro; Miuchi, Kentaro; Mizumoto, Tetsuya; Nakamasu, Yuma; Nakamura, Kiseki; Parker, Joseph D.; Sawano, Tatsuya; Sonoda, Shinya; Tomono, Dai; Yoshikawa, Kei

    2017-01-01

    Since the discovery of nuclear gamma-rays, its imaging has been limited to pseudo imaging, such as Compton Camera (CC) and coded mask. Pseudo imaging does not keep physical information (intensity, or brightness in Optics) along a ray, and thus is capable of no more than qualitative imaging of bright objects. To attain quantitative imaging, cameras that realize geometrical optics is essential, which would be, for nuclear MeV gammas, only possible via complete reconstruction of the Compton process. Recently we have revealed that “Electron Tracking Compton Camera” (ETCC) provides a well-defined Point Spread Function (PSF). The information of an incoming gamma is kept along a ray with the PSF and that is equivalent to geometrical optics. Here we present an imaging-spectroscopic measurement with the ETCC. Our results highlight the intrinsic difficulty with CCs in performing accurate imaging, and show that the ETCC surmounts this problem. The imaging capability also helps the ETCC suppress the noise level dramatically by ~3 orders of magnitude without a shielding structure. Furthermore, full reconstruction of Compton process with the ETCC provides spectra free of Compton edges. These results mark the first proper imaging of nuclear gammas based on the genuine geometrical optics. PMID:28155870

  19. Precision X-Band Linac Technologies for Nuclear Photonics Gamma-Ray Sources

    SciTech Connect

    Hartemann, F V; Albert, F; Anderson, S G; Bayramian, A J; Cross, R R; Ebbers, C A; Gibson, D J; Houck, T L; Marsh, R A; Messerly, M J; Siders, C W; McNabb, D P; Barty, C J; Adolphsen, C E; Chu, T S; Jongewaard, E N; Tantawi, S G; Vlieks, A E; Wang, F; Wang, J W; Raubenheimer, T O; Ighigeanu, D; Toma, M; Cutoiu, D

    2011-08-31

    Nuclear photonics is an emerging field of research requiring new tools, including high spectral brightness, tunable gamma-ray sources; high photon energy, ultrahigh-resolution crystal spectrometers; and novel detectors. This presentation focuses on the precision linac technology required for Compton scattering gamma-ray light sources, and on the optimization of the laser and electron beam pulse format to achieve unprecedented spectral brightness. Within this context, high-gradient X-band technology will be shown to offer optimal performance in a compact package, when used in conjunction with the appropriate pulse format, and photocathode illumination and interaction laser technologies. The nascent field of nuclear photonics is enabled by the recent maturation of new technologies, including high-gradient X-band electron acceleration, robust fiber laser systems, and hyper-dispersion CPA. Recent work has been performed at LLNL to demonstrate isotope-specific detection of shielded materials via NRF using a tunable, quasi-monochromatic Compton scattering gamma-ray source operating between 0.2 MeV and 0.9 MeV photon energy. This technique is called Fluorescence Imaging in the Nuclear Domain with Energetic Radiation (or FINDER). This work has, among other things, demonstrated the detection of {sup 7}Li shielded by Pb, utilizing gamma rays generated by a linac-driven, laser-based Compton scattering gamma-ray source developed at LLNL. Within this context, a new facility is currently under construction at LLNL, with the goal of generating tunable {gamma}-rays in the 0.5-2.5 MeV photon energy range, at a repetition rate of 120 Hz, and with a peak brightness in the 10{sup 20} photons/(s x mm{sup 2} x mrad{sup 2} x 0.1% bw).

  20. New Approaches to Quantum Computing using Nuclear Magnetic Resonance Spectroscopy

    SciTech Connect

    Colvin, M; Krishnan, V V

    2003-02-07

    The power of a quantum computer (QC) relies on the fundamental concept of the superposition in quantum mechanics and thus allowing an inherent large-scale parallelization of computation. In a QC, binary information embodied in a quantum system, such as spin degrees of freedom of a spin-1/2 particle forms the qubits (quantum mechanical bits), over which appropriate logical gates perform the computation. In classical computers, the basic unit of information is the bit, which can take a value of either 0 or 1. Bits are connected together by logic gates to form logic circuits to implement complex logical operations. The expansion of modern computers has been driven by the developments of faster, smaller and cheaper logic gates. As the size of the logic gates become smaller toward the level of atomic dimensions, the performance of such a system is no longer considered classical but is rather governed by quantum mechanics. Quantum computers offer the potentially superior prospect of solving computational problems that are intractable to classical computers such as efficient database searches and cryptography. A variety of algorithms have been developed recently, most notably Shor's algorithm for factorizing long numbers into prime factors in polynomial time and Grover's quantum search algorithm. The algorithms that were of only theoretical interest as recently, until several methods were proposed to build an experimental QC. These methods include, trapped ions, cavity-QED, coupled quantum dots, Josephson junctions, spin resonance transistors, linear optics and nuclear magnetic resonance. Nuclear magnetic resonance (NMR) is uniquely capable of constructing small QCs and several algorithms have been implemented successfully. NMR-QC differs from other implementations in one important way that it is not a single QC, but a statistical ensemble of them. Thus, quantum computing based on NMR is considered as ensemble quantum computing. In NMR quantum computing, the spins with

  1. Probing nuclear shapes close to the fission limit with the giant dipole resonance in {sup 216}Rn

    SciTech Connect

    Kmiecik, M.; Maj, A.; Brekiesz, M.; Krolas, W.; Meczynski, W.; Styczen, J.; Zieblinski, M.; Million, B.; Bracco, A.; Camera, F.; Benzoni, G.; Leoni, S.; Wieland, O.; Brambilla, S.; Herskind, B.; Kicinska-Habior, M.; Dubray, N.; Dudek, J.; Schunck, N.

    2004-12-01

    The gamma-ray decay of the giant dipole resonance (GDR) in the compound nucleus {sup 216}Rn formed with the reaction {sup 18}O+{sup 198}Pt at the bombarding energy of 96 MeV was investigated. High-energy gamma-ray spectra in coincidence with both prompt and delayed low-energy transitions were measured. The obtained GDR width at the average temperature {approx_equal}1 MeV was found to be larger than that at T=0 MeV and to be approximately constant as a function of spin. The measured width value of 7 MeV is found to be consistent with the predictions based on calculations of the nuclear shape distribution using the newest approach for the treatment of the fission barrier within the liquid drop model. The present study is the first investigation of the giant dipole resonance width from the fusion-evaporation decay channel in this nuclear mass range.

  2. Initial results from a multiple monoenergetic gamma radiography system for nuclear security

    NASA Astrophysics Data System (ADS)

    O'Day, Buckley E.; Hartwig, Zachary S.; Lanza, Richard C.; Danagoulian, Areg

    2016-10-01

    The detection of assembled nuclear devices and concealed special nuclear materials (SNM) such as plutonium or uranium in commercial cargo traffic is a major challenge in mitigating the threat of nuclear terrorism. Currently available radiographic and active interrogation systems use ∼1-10 MeV bremsstrahlung photon beams. Although simple to build and operate, bremsstrahlung-based systems deliver high radiation doses to the cargo and to potential stowaways. To eliminate problematic issues of high dose, we are developing a novel technique known as multiple monoenergetic gamma radiography (MMGR). MMGR uses ion-induced nuclear reactions to produce two monoenergetic gammas for dual-energy radiography. This allows us to image the areal density and effective atomic number (Zeff) of scanned cargo. We present initial results from the proof-of-concept experiment, which was conducted at the MIT Bates Research and Engineering Center. The purpose of the experiment was to assess the capabilities of MMGR to measure areal density and Zeff of container cargo mockups. The experiment used a 3.0 MeV radiofrequency quadrupole accelerator to create sources of 4.44 MeV and 15.11 MeV gammas from the 11B(d,nγ)12C reaction in a thick natural boron target; the gammas are detected by an array of NaI(Tl) detectors after transmission through cargo mockups . The measured fluxes of transmitted 4.44 MeV and 15.11 MeV gammas were used to assess the areal density and Zeff. Initial results show that MMGR is capable of discriminating the presence of high-Z materials concealed in up to 30 cm of iron shielding from low- and mid-Z materials present in the cargo mockup.

  3. Nuclear magnetic resonance studies of macroscopic morphology and dynamics

    SciTech Connect

    Barrall, Geoffrey Alden

    1995-09-01

    Nuclear magnetic resonance techniques are traditionally used to study molecular level structure and dynamics with a noted exception in medically applied NMR imaging (MRI). In this work, new experimental methods and theory are presented relevant to the study of macroscopic morphology and dynamics using NMR field gradient techniques and solid state two-dimensional exchange NMR. The goal in this work is not to take some particular system and study it in great detail, rather it is to show the utility of a number of new and novel techniques using ideal systems primarily as a proof of principle. By taking advantage of the analogy between NMR imaging and diffraction, one may simplify the experiments necessary for characterizing the statistical properties of the sample morphology. For a sample composed of many small features, e.g. a porous medium, the NMR diffraction techniques take advantage of both the narrow spatial range and spatial isotropy of the sample`s density autocorrelation function to obtain high resolution structural information in considerably less time than that required by conventional NMR imaging approaches. The time savings of the technique indicates that NMR diffraction is capable of finer spatial resolution than conventional NMR imaging techniques. Radio frequency NMR imaging with a coaxial resonator represents the first use of cylindrically symmetric field gradients in imaging. The apparatus as built has achieved resolution at the micron level for water samples, and has the potential to be very useful in the imaging of circularly symmetric systems. The study of displacement probability densities in flow through a random porous medium has revealed the presence of features related to the interconnectedness of the void volumes. The pulsed gradient techniques used have proven successful at measuring flow properties for time and length scales considerably shorter than those studied by more conventional techniques.

  4. Comparison of Radionuclide Ratios in Atmospheric Nuclear Explosions and Nuclear Releases from Chernobyl and Fukushima seen in Gamma Ray Spectormetry

    SciTech Connect

    Friese, Judah I.; Kephart, Rosara F.; Lucas, Dawn D.

    2013-05-01

    The Comprehensive Nuclear Test Ban Treaty (CTBT) has remote radionuclide monitoring followed by an On Site Inspection (OSI) to clarify the nature of a suspect event. An important aspect of radionuclide measurements on site is the discrimination of other potential sources of similar radionuclides such as reactor accidents or medical isotope production. The Chernobyl and Fukushima nuclear reactor disasters offer two different reactor source term environmental inputs that can be compared against historical measurements of nuclear explosions. The comparison of whole-sample gamma spectrometry measurements from these three events and the analysis of similarities and differences are presented. This analysis is a step toward confirming what is needed for measurements during an OSI under the auspices of the Comprehensive Test Ban Treaty.

  5. Phenotypic screening of hepatocyte nuclear factor (HNF) 4-{gamma} receptor knockout mice

    SciTech Connect

    Gerdin, Anna Karin; Surve, Vikas V.; Joensson, Marie; Bjursell, Mikael; Edenro, Anne; Schuelke, Meint; Saad, Alaa; Bjurstroem, Sivert; Lundgren, Elisabeth Jensen; Snaith, Michael; Fransson-Steen, Ronny; Toernell, Jan; Bohlooly-Y, Mohammad . E-mail: mohammad.bohlooly@astrazeneca.com

    2006-10-20

    Using the mouse as a model organism in pharmaceutical research presents unique advantages as its physiology in many ways resembles the human physiology, it also has a relatively short generation time, low breeding and maintenance costs, and is available in a wide variety of inbred strains. The ability to genetically modify mouse embryonic stem cells to generate mouse models that better mimic human disease is another advantage. In the present study, a comprehensive phenotypic screening protocol is applied to elucidate the phenotype of a novel mouse knockout model of hepatocyte nuclear factor (HNF) 4-{gamma}. HNF4-{gamma} is expressed in the kidneys, gut, pancreas, and testis. First level of the screen is aimed at general health, morphologic appearance, normal cage behaviour, and gross neurological functions. The second level of the screen looks at metabolic characteristics and lung function. The third level of the screen investigates behaviour more in-depth and the fourth level consists of a thorough pathological characterisation, blood chemistry, haematology, and bone marrow analysis. When compared with littermate wild-type mice (HNF4-{gamma}{sup +/+}), the HNF4-{gamma} knockout (HNF4-{gamma}{sup -/-}) mice had lowered energy expenditure and locomotor activity during night time that resulted in a higher body weight despite having reduced intake of food and water. HNF4-{gamma}{sup -/-} mice were less inclined to build nest and were found to spend more time in a passive state during the forced swim test.

  6. Developing hyperpolarized krypton-83 for nuclear magnetic resonance spectroscopy and magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Cleveland, Zackary I.

    This dissertation discusses the production of highly nonequilibrium nuclear spin polarization, referred to as hyperpolarization or hp, in the nuclear spin I = 9/2 noble gas isotope krypton-83 using spin exchange optical pumping (SEOP). This nonequilibrium polarization yields nuclear magnetic resonance (NMR) signals that are enhanced three or more orders of magnitude above those of thermally polarized krypton and enables experiments that would otherwise be impossible. Krypton-83 possesses a nuclear electric quadrupole moment that dominates the longitudinal (T1) relaxation due to coupling of the quadrupole moment to fluctuating electric field gradients generated by distortions to the spherical symmetry of the electronic environment. Relaxation slows polarization buildup and limits the maximum signal intensity but makes krypton-83 a sensitive probe of its environment. The gas-phase krypton-83 longitudinal relaxation rate increases linearly with total gas density due to binary collisions. Density independent relaxation, caused by the formation of krypton-krypton van der Waals molecules and surface adsorption, also contributes to the observed rate. Buffer gases suppress van der Waals molecule mediated relaxation by breaking apart the weakly bound krypton dimers. Surface relaxation is gas composition independent and therefore more difficult to suppress. However, this relaxation mechanism makes hp krypton-83 sensitive to important surface properties including surface-to-volume ratio, surface chemistry, and surface temperature. The presence of surfaces with high krypton adsorption affinities (i.e. hydrophobic surfaces) accelerates the relaxation times and can produce T1 contrast in hp krypton-83 magnetic resonance imaging (MRI). Tobacco smoke deposited on surfaces generates strong T1 contrast allowing the observation of smoke deposition with spatial resolution. Conversely, water adsorption on surfaces significantly lengths the T1 times due competitive surface adsorption

  7. Electron-nuclear-nuclear triple resonance of cis-rich polyacetylene —Evidence for negative spin sites of soliton

    NASA Astrophysics Data System (ADS)

    Kuroda, S.; Shirakawa, H.

    1991-03-01

    Electron-nuclear double resonance (ENDOR) and electron-nuclear-nuclear triple resonance (TRIPLE) spectra of stretch-oriented cis-rich polyacetylene at low temperatures show clear spectral turning points when the external magnetic field is parallel to the stretch direction. The difference between ENDOR and TRIPLE spectra, depending on the pumping frequency of the latter, provide direct evidence that the turning points are associated with the negative spin sites of the soliton, arising from electron correlation effect, as predicted from our previous ENDOR analysis.

  8. Solar flare nuclear gamma-rays and interplanetary proton events

    NASA Technical Reports Server (NTRS)

    Cliver, E. W.; Forrest, D. J.; Cane, H. V.; Reames, D. V.; Mcguire, R. E.; Von Rosenvinge, T. T.

    1989-01-01

    Gamma-ray line (GRL) and solar energetic proton (SEP) events observed from February 1980 through January 1985 are compared in order to substantiate and better characterize the lack of correlation between GRL fluences and SEP event peak fluxes. The scatter plot of SEP event peak flux vs. GRL fluence is presented, and the ratio of 'solar' to 'interplanetary', about 10 MeV protons, is presented. It is shown that, while even large SEP events can originate in flares lacking detectable GRL emission, the converse case of flares with a significant GRL line fluence by lacking protons in space is rare. The ratio R of the number of about 10 MeV protons that produce GRL emission at the flare site to the number of about 10 MeV protons detected in space can vary from event to event by four orders of magnitude. There is a clear tendency for impulsive flares to have larger values of R than long-duration flares, where the flare time scale is given by the e-folding decay time of the associated soft X-ray emission.

  9. New Versions of Terahertz Radiation Sources for Dynamic Nuclear Polarization in Nuclear Magnetic Resonance Spectroscopy

    NASA Astrophysics Data System (ADS)

    Bratman, V. L.; Kalynov, Yu. K.; Makhalov, P. B.; Fedotov, A. E.

    2014-01-01

    Dynamic nuclear polarization in strong-field nuclear magnetic resonance (NMR) spectroscopy requires terahertz radiation with moderate power levels. Nowadays, conventional gyrotrons are used almost exclusively to generate such radiation. In this review paper, we consider alternative variants of electronic microwave oscillators which require much weaker magnetic fields for their operation, namely, large-orbit gyrotrons operated at high cyclotron-frequency harmonics and Čerenkov-type devices, such as a backward-wave oscillator and a klystron frequency multiplier with tubular electron beams. Additionally, we consider the possibility to use the magnetic field created directly by the solenoid of an NMR spectrometer for operation of both the gyrotron and the backward-wave oscillator. Location of the oscillator in the spectrometer magnet makes it superfluous to use an additional superconducting magnet creating a strong field, significantly reduces the length of the radiation transmission line, and, in the case of Čerenkov-type devices, allows one to increase considerably the output-signal power. According to our calculations, all the electronic devices considered are capable of ensuring the power required for dynamic nuclear polarization (10 W or more) at a frequency of 260 GHz, whereas the gyrotrons, including their versions proposed in this paper, remain a single option at higher frequencies.

  10. Measurement of {sup 25}Al+p resonant elastic scattering for studying the {sup 25}Al(p,{gamma}){sup 26}Si

    SciTech Connect

    Kwon, Y. K.; Lee, C. S.; Jung, H. S.; Moon, J. Y.; Lee, J. H.; Yun, C. C.; Kubono, S.; Yamaguchi, H.; Hashimoto, T.; Kahl, D.; Hayakawa, S.; Choi, Seonho; Kim, M. J.; Kim, Y. H.; Kim, Y. K.; Park, J. S.; Kim, E. J.; Moon, C.-B.; Teranishi, T.; Wakabayashi, Y.; and others

    2012-11-12

    Proton resonant states in {sup 26}Si have been studied by the resonant elastic scattering of {sup 25}Al+p with a {sup 25}Al radioactive ion beam at 2.863 MeV/nucleon bombarding a thick H{sub 2} gas target with the inverse kinematics method at the low-energy RI beam facility CRIB (CNS Radioactive Ion Beam separator), University of Tokyo. The properties of these resonance states are important to better determine the production rates of {sup 25}Al(p,{gamma}){sup 26}Si reaction, which is one of the astrophysically important nuclear reactions to understand the production of the ground state of {sup 26}Al, the emitter of its characteristic 1.809-MeV gamma-ray, under the explosive stellar environments such as novae and X-ray bursts. In this work, several resonances above the proton threshold level have been observed with a high statistics and background free through a covered the range of excitation energies from E{sub x}{approx} 6.8 to 8.2 MeV.

  11. Advances in Nuclear Magnetic Resonance for Drug Discovery

    PubMed Central

    Powers, Robert

    2010-01-01

    Background Drug discovery is a complex and unpredictable endeavor with a high failure rate. Current trends in the pharmaceutical industry have exasperated these challenges and are contributing to the dramatic decline in productivity observed over the last decade. The industrialization of science by forcing the drug discovery process to adhere to assembly-line protocols is imposing unnecessary restrictions, such as short project time-lines. Recent advances in nuclear magnetic resonance are responding to these self-imposed limitations and are providing opportunities to increase the success rate of drug discovery. Objective/Method A review of recent advancements in NMR technology that have the potential of significantly impacting and benefiting the drug discovery process will be presented. These include fast NMR data collection protocols and high-throughput protein structure determination, rapid protein-ligand co-structure determination, lead discovery using fragment-based NMR affinity screens, NMR metabolomics to monitor in vivo efficacy and toxicity for lead compounds, and the identification of new therapeutic targets through the functional annotation of proteins by FAST-NMR. Conclusion NMR is a critical component of the drug discovery process, where the versatility of the technique enables it to continually expand and evolve its role. NMR is expected to maintain this growth over the next decade with advancements in automation, speed of structure calculation, in-cell imaging techniques, and the expansion of NMR amenable targets. PMID:20333269

  12. Updated methodology for nuclear magnetic resonance characterization of shales

    USGS Publications Warehouse

    Washburn, Kathryn E.; Birdwell, Justin E.

    2013-01-01

    Unconventional petroleum resources, particularly in shales, are expected to play an increasingly important role in the world’s energy portfolio in the coming years. Nuclear magnetic resonance (NMR), particularly at low-field, provides important information in the evaluation of shale resources. Most of the low-field NMR analyses performed on shale samples rely heavily on standard T1 and T2 measurements. We present a new approach using solid echoes in the measurement of T1 and T1–T2 correlations that addresses some of the challenges encountered when making NMR measurements on shale samples compared to conventional reservoir rocks. Combining these techniques with standard T1 and T2 measurements provides a more complete assessment of the hydrogen-bearing constituents (e.g., bitumen, kerogen, clay-bound water) in shale samples. These methods are applied to immature and pyrolyzed oil shale samples to examine the solid and highly viscous organic phases present during the petroleum generation process. The solid echo measurements produce additional signal in the oil shale samples compared to the standard methodologies, indicating the presence of components undergoing homonuclear dipolar coupling. The results presented here include the first low-field NMR measurements performed on kerogen as well as detailed NMR analysis of highly viscous thermally generated bitumen present in pyrolyzed oil shale.

  13. Water Permeability of Chlorella Cell Membranes by Nuclear Magnetic Resonance

    PubMed Central

    Stout, Darryl G.; Steponkus, Peter L.; Bustard, Larry D.; Cotts, Robert M.

    1978-01-01

    Measurement by two nuclear magnetic resonance (NMR) techniques of the mean residence time τa of water molecules inside Chlorella vulgaris (Beijerinck) var. “viridis” (Chodot) is reported. The first is the Conlon and Outhred (1972 Biochim Biophys Acta 288: 354-361) technique in which extracellular water is doped with paramagnetic Mn2+ ions. Some complications in application of this technique are identified as being caused by the affinity of Chlorella cell walls for Mn2+ ions which shortens the NMR relaxation times of intra- and extracellular water. The second is based upon observations of effects of diffusion on the spin echo of intra- and extracellular water. Echo attenuation of intracellular water is distinguished from that of extracellular water by the extent to which diffusive motion is restricted. Intracellular water, being restricted to the cell volume, suffers less echo attenuation. From the dependence of echo amplitude upon gradient strength at several values of echo time, the mean residence time of intracellular water can be determined. From the mean residence time of intracellular water, the diffusional water permeability coefficient of the Chlorella membrane is calculated to be 2.1 ± 0.4 × 10−3 cm sec−1. PMID:16660456

  14. Optically Pumped Nuclear Magnetic Resonance in the Quantum Hall Regimes

    NASA Astrophysics Data System (ADS)

    Barrett, S. E.; Khandelwal, P.; Kuzma, N. N.; Pfeiffer, L. N.; West, K. W.

    1997-03-01

    Optical pumping enables the direct detection of the nuclear magnetic resonance signal of ^71Ga nuclei located in an electron doped GaAs quantum well.footnote S. E. Barrett et al., Phys. Rev. Lett. 72, 1368 (1994) Using this technique, measurements of the Knight shift (K_S)footnote S. E. Barrett et al., Phys. Rev. Lett. 74, 5112 (1995) and spin-lattice relaxation time (T_1)footnote R. Tycko et al., Science 268, 1460 (1995) have been carried out in the Quantum Hall regimes. This talk will focus on our latest measurements of KS and T1 near Landau level filling ν=1, which extend our earlier results to higher magnetic fields (B=12 Tesla) and lower temperatures (T < 1 Kelvin). We will compare these results to the theoretical predictionsfootnote S. L. Sondhi et al., Phys. Rev. B 47, 16419 (1993); H. A. Fertig et al., Phys. Rev. B 50, 11018 (1994) that the charged excitations of the ν = 1 ground state are novel spin textures called skyrmions. The current status of this picture will be discussed.

  15. Updated methodology for nuclear magnetic resonance characterization of shales

    NASA Astrophysics Data System (ADS)

    Washburn, Kathryn E.; Birdwell, Justin E.

    2013-08-01

    Unconventional petroleum resources, particularly in shales, are expected to play an increasingly important role in the world's energy portfolio in the coming years. Nuclear magnetic resonance (NMR), particularly at low-field, provides important information in the evaluation of shale resources. Most of the low-field NMR analyses performed on shale samples rely heavily on standard T1 and T2 measurements. We present a new approach using solid echoes in the measurement of T1 and T1-T2 correlations that addresses some of the challenges encountered when making NMR measurements on shale samples compared to conventional reservoir rocks. Combining these techniques with standard T1 and T2 measurements provides a more complete assessment of the hydrogen-bearing constituents (e.g., bitumen, kerogen, clay-bound water) in shale samples. These methods are applied to immature and pyrolyzed oil shale samples to examine the solid and highly viscous organic phases present during the petroleum generation process. The solid echo measurements produce additional signal in the oil shale samples compared to the standard methodologies, indicating the presence of components undergoing homonuclear dipolar coupling. The results presented here include the first low-field NMR measurements performed on kerogen as well as detailed NMR analysis of highly viscous thermally generated bitumen present in pyrolyzed oil shale.

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

    SciTech Connect

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

    2007-03-15

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

  17. High-resolution two-field nuclear magnetic resonance spectroscopy.

    PubMed

    Cousin, Samuel F; Charlier, Cyril; Kadeřávek, Pavel; Marquardsen, Thorsten; Tyburn, Jean-Max; Bovier, Pierre-Alain; Ulzega, Simone; Speck, Thomas; Wilhelm, Dirk; Engelke, Frank; Maas, Werner; Sakellariou, Dimitrios; Bodenhausen, Geoffrey; Pelupessy, Philippe; Ferrage, Fabien

    2016-12-07

    Nuclear magnetic resonance (NMR) is a ubiquitous branch of spectroscopy that can explore matter at the scale of an atom. Significant improvements in sensitivity and resolution have been driven by a steady increase of static magnetic field strengths. However, some properties of nuclei may be more favourable at low magnetic fields. For example, transverse relaxation due to chemical shift anisotropy increases sharply at higher magnetic fields leading to line-broadening and inefficient coherence transfers. Here, we present a two-field NMR spectrometer that permits the application of rf-pulses and acquisition of NMR signals in two magnetic centres. Our prototype operates at 14.1 T and 0.33 T. The main features of this system are demonstrated by novel NMR experiments, in particular a proof-of-concept correlation between zero-quantum coherences at low magnetic field and single quantum coherences at high magnetic field, so that high resolution can be achieved in both dimensions, despite a ca. 10 ppm inhomogeneity of the low-field centre. Two-field NMR spectroscopy offers the possibility to circumvent the limits of high magnetic fields, while benefiting from their exceptional sensitivity and resolution. This approach opens new avenues for NMR above 1 GHz.

  18. Discrete decoding based ultrafast multidimensional nuclear magnetic resonance spectroscopy

    SciTech Connect

    Wei, Zhiliang; Lin, Liangjie; Ye, Qimiao; Li, Jing; Cai, Shuhui; Chen, Zhong

    2015-07-14

    The three-dimensional (3D) nuclear magnetic resonance (NMR) spectroscopy constitutes an important and powerful tool in analyzing chemical and biological systems. However, the abundant 3D information arrives at the expense of long acquisition times lasting hours or even days. Therefore, there has been a continuous interest in developing techniques to accelerate recordings of 3D NMR spectra, among which the ultrafast spatiotemporal encoding technique supplies impressive acquisition speed by compressing a multidimensional spectrum in a single scan. However, it tends to suffer from tradeoffs among spectral widths in different dimensions, which deteriorates in cases of NMR spectroscopy with more dimensions. In this study, the discrete decoding is proposed to liberate the ultrafast technique from tradeoffs among spectral widths in different dimensions by focusing decoding on signal-bearing sites. For verifying its feasibility and effectiveness, we utilized the method to generate two different types of 3D spectra. The proposed method is also applicable to cases with more than three dimensions, which, based on the experimental results, may widen applications of the ultrafast technique.

  19. Nuclear Magnetic Resonance Spectroscopy-Based Identification of Yeast.

    PubMed

    Himmelreich, Uwe; Sorrell, Tania C; Daniel, Heide-Marie

    2017-01-01

    Rapid and robust high-throughput identification of environmental, industrial, or clinical yeast isolates is important whenever relatively large numbers of samples need to be processed in a cost-efficient way. Nuclear magnetic resonance (NMR) spectroscopy generates complex data based on metabolite profiles, chemical composition and possibly on medium consumption, which can not only be used for the assessment of metabolic pathways but also for accurate identification of yeast down to the subspecies level. Initial results on NMR based yeast identification where comparable with conventional and DNA-based identification. Potential advantages of NMR spectroscopy in mycological laboratories include not only accurate identification but also the potential of automated sample delivery, automated analysis using computer-based methods, rapid turnaround time, high throughput, and low running costs.We describe here the sample preparation, data acquisition and analysis for NMR-based yeast identification. In addition, a roadmap for the development of classification strategies is given that will result in the acquisition of a database and analysis algorithms for yeast identification in different environments.

  20. Two-dimensional nuclear magnetic resonance of quadrupolar systems

    SciTech Connect

    Wang, Shuanhu

    1997-09-01

    This dissertation describes two-dimensional nuclear magnetic resonance theory and experiments which have been developed to study quadruples in the solid state. The technique of multiple-quantum magic-angle spinning (MQMAS) is extensively reviewed and expanded upon in this thesis. Specifically, MQMAS is first compared with another technique, dynamic-angle spinning (DAS). The similarity between the two techniques allows us to extend much of the DAS work to the MQMAS case. Application of MQMAS to a series of aluminum containing materials is then presented. The superior resolution enhancement through MQMAS is exploited to detect the five- and six-coordinated aluminum in many aluminosilicate glasses. Combining the MQMAS method with other experiments, such as HETCOR, greatly expands the possibility of the use of MQMAS to study a large range of problems and is demonstrated in Chapter 5. Finally, the technique switching-angle spinning (SAS) is applied to quadrupolar nuclei to fully characterize a quadrupolar spin system in which all of the 8 NMR parameters are accurately determined. This dissertation is meant to demonstrate that with the combination of two-dimensional NMR concepts and new advanced spinning technologies, a series of multiple-dimensional NMR techniques can be designed to allow a detailed study of quadrupolar nuclei in the solid state.

  1. Nuclear magnetic resonance studies of bovine γB-crystallin

    NASA Astrophysics Data System (ADS)

    Thurston, George; Mills, Jeffrey; Michel, Lea; Mathews, Kaylee; Zanet, John; Payan, Angel; van Nostrand, Keith; Kotlarchyk, Michael; Ross, David; Wahle, Christopher; Hamilton, John

    Anisotropy of shape and/or interactions play an important role in determining the properties of concentrated solutions of the eye lens protein, γB-crystallin, including its liquid-liquid phase transition. We are studying γB anisotropic interactions with use of nuclear magnetic resonance (NMR) concentration- and temperature-dependent chemical shift perturbations (CSPs). We analyze two-dimensional heteronuclear spin quantum coherence (HSQC) spectra on backbone nitrogen and attached hydrogen nuclei for CSPs, up to 3 percent volume fraction. Cumulative distribution functions of the CSPs show a concentration and temperature-dependent spread. Many peaks that are highly shifted with either concentration or temperature are close (i) crystal intermolecular contacts (ii) locations of cataractogenic point mutations of a homologous human protein, human γD-crystallin, and (iii) charged amino-acid residues. We also discuss the concentration- and temperature-dependence of NMR and quasielastic light scattering measurements of rotational and translational diffusion of γB crystallin in solution, affected by interprotein attractions. Supported by NIH EY018249.

  2. Polarization enhanced Nuclear Quadrupole Resonance with an atomic magnetometer

    NASA Astrophysics Data System (ADS)

    Malone, Michael W.; Barrall, Geoffrey A.; Espy, Michelle A.; Monti, Mark C.; Alexson, Dimitri A.; Okamitsu, Jeffrey K.

    2016-05-01

    Nuclear Quadrupole Resonance (NQR) has been demonstrated for the detection of 14-N in explosive compounds. Application of a material specific radio-frequency (RF) pulse excites a response typically detected with a wire- wound antenna. NQR is non-contact and material specific, however fields produced by NQR are typically very weak, making demonstration of practical utility challenging. For certain materials, the NQR signal can be increased by transferring polarization from hydrogen nuclei to nitrogen nuclei using external magnetic fields. This polarization enhancement (PE) can enhance the NQR signal by an order of magnitude or more. Atomic magnetometers (AM) have been shown to improve detection sensitivity beyond a conventional antenna by a similar amount. AM sensors are immune to piezo-electric effects that hamper conventional NQR, and can be combined to form a gradiometer for effective RF noise cancellation. In principle, combining polarization enhancement with atomic magnetometer detection should yield improvement in signal-to-noise ratio that is the product of the two methods, 100-fold or more over conventional NQR. However both methods are even more exotic than traditional NQR, and have never been combined due to challenges in operating a large magnetic field and ultra-sensitive magnetic field sensor in proximity. Here we present NQR with and without PE with an atomic magnetometer, demonstrating signal enhancement greater than 20-fold for ammonium nitrate. We also demonstrate PE for PETN using a traditional coil for detection with an enhancement factor of 10. Experimental methods and future applications are discussed.

  3. Nuclear magnetic resonance proton imaging of bone pathology

    SciTech Connect

    Atlan, H.; Sigal, R.; Hadar, H.; Chisin, R.; Cohen, I.; Lanir, A.; Soudry, M.; Machtey, Y.; Schreiber, R.; Benmair, J.

    1986-02-01

    Thirty-two patients with diversified pathology were examined with a supraconductive NMR imager using spin echo with different TR and TE to obtain T1 and T2 weighted images. They included 20 tumors (12 primary, eight metastasis), six osteomyelitis, three fractures, two osteonecrosis, and one diffuse metabolic (Gaucher) disease. In all cases except for the stress fractures, the bone pathology was clearly visualized in spite of the normal lack of signal from the compact cortical bone. Nuclear magnetic resonance (NMR) imaging proved to be at least as sensitive as radionuclide scintigraphy but much more accurate than all other imaging procedures including computed tomography (CT) and angiography to assess the extension of the lesions, especially in tumors extended to soft tissue. This is due both to easy acquisition of sagittal and coronal sections and to different patterns of pathologic modifications of T1 and T2 which are beginning to be defined. It is hoped that more experience in clinical use of these patterns will help to discriminate between tumor extension and soft-tissue edema. We conclude that while radionuclide scintigraphy will probably remain the most sensitive and easy to perform screening test for bone pathology, NMR imaging, among noninvasive diagnostic procedures, appears to be at least as specific as CT. In addition, where the extension of the lesions is concerned, NMR imaging is much more informative than CT. In pathology of the spine, the easy visualization of the spinal cord should decrease the need for myelography.

  4. Nuclear magnetic resonance metabolomics of iron deficiency in soybean leaves.

    PubMed

    Lima, Marta R M; Diaz, Sílvia O; Lamego, Inês; Grusak, Michael A; Vasconcelos, Marta W; Gil, Ana M

    2014-06-06

    Iron (Fe) deficiency is an important agricultural concern that leads to lower yields and crop quality. A better understanding of the condition at the metabolome level could contribute to the design of strategies to ameliorate Fe-deficiency problems. Fe-sufficient and Fe-deficient soybean leaf extracts and whole leaves were analyzed by liquid (1)H nuclear magnetic resonance (NMR) and high-resolution magic-angle spinning NMR spectroscopy, respectively. Overall, 30 compounds were measurable and identifiable (comprising amino and organic acids, fatty acids, carbohydrates, alcohols, polyphenols, and others), along with 22 additional spin systems (still unassigned). Thus, metabolite differences between treatment conditions could be evaluated for different compound families simultaneously. Statistically relevant metabolite changes upon Fe deficiency included higher levels of alanine, asparagine/aspartate, threonine, valine, GABA, acetate, choline, ethanolamine, hypoxanthine, trigonelline, and polyphenols and lower levels of citrate, malate, ethanol, methanol, chlorogenate, and 3-methyl-2-oxovalerate. The data indicate that the main metabolic impacts of Fe deficiency in soybean include enhanced tricarboxylic acid cycle activity, enhanced activation of oxidative stress protection mechanisms and enhanced amino acid accumulation. Metabolites showing accumulation differences in Fe-starved but visually asymptomatic leaves could serve as biomarkers for early detection of Fe-deficiency stress.

  5. Nuclear magnetic resonance imaging of water content in the subsurface

    SciTech Connect

    J. Hendricks; T. Yao; A. Kearns

    1999-01-21

    Previous theoretical and experimental studies indicated that surface nuclear magnetic resonance (NMR) has the potential to provide cost-effective water content measurements in the subsurface and is a technology ripe for exploitation in practice. The objectives of this investigation are (a) to test the technique under a wide range of hydrogeological conditions and (b) to generalize existing NMR theories in order to correctly model NMR response from conductive ground and to assess properties of the inverse problem. Twenty-four sites with different hydrogeologic settings were selected in New Mexico and Colorado for testing. The greatest limitation of surface NMR technology appears to be the lack of understanding in which manner the NMR signal is influenced by soil-water factors such as pore size distribution, surface-to-volume ratio, paramagnetic ions dissolved in the ground water, and the presence of ferromagnetic minerals. Although the theoretical basis is found to be sound, several advances need to be made to make surface NMR a viable technology for hydrological investigations. There is a research need to investigate, under controlled laboratory conditions, how the complex factors of soil-water systems affect NMR relaxation times.

  6. Nuclear resonance tomography with a toroid cavity detector

    DOEpatents

    Woelk, K.; Rathke, J.W.; Klingler, R.J.

    1996-11-12

    A toroid cavity detection system is described for determining the spectral properties and distance from a fixed point for a sample using Nuclear Magnetic Resonance. The detection system consists of a toroid with a central conductor oriented along the main axis of the toroidal cylinder and perpendicular to a static uniform magnetic field oriented along the main axis of the toroid. An rf signal is input to the central conductor to produce a magnetic field perpendicular to the central axis of the toroid and whose field strength varies as the inverse of the radius of the toroid. The toroid cavity detection system can be used to encapsulate a sample, or the detection system can be perforated to allow a sample to flow into the detection device or to place the samples in specified sample tubes. The central conductor can also be coated to determine the spectral property of the coating and the coating thickness. The sample is then subjected to the respective magnetic fields and the responses measured to determine the desired properties. 4 figs.

  7. Work in progress: nuclear magnetic resonance imaging of the gallbladder

    SciTech Connect

    Hricak, H.; Filly, R.A.; Margulis, A.R.; Moon, K.L.; Crooks, L.E.; Kaufman, L.

    1983-05-01

    A preliminary study of the relation between food intake and intensity of gallbladder bile on nuclear magnetic resonance (NMR) images was made. Twelve subjects (seven volunteers, five patients) were imaged following a minimum of 14 hours of fasting. Six of seven volunteers were reimaged one hour after stimulation by either a fatty meal or an alcoholic beverage. An additional seven patients were imaged two hours after a hospital breakfast. It was found that concentrated bile emits a high-intensity spin echo signal (SE), while hepatic bile in the gallbladder produces a low-intensity SE signal. Following ingestion of cholecystogogue, dilute hepatic bile settles on top of the concentrated bile, each emitting SE signals of different intensity. The average T1 value of concentrated bile was 594 msec, while the T1 vaue of dilute hepatic bile was 2,646 msec. The average T2 values were 104 msec for concentrated bile and 126 msec for dilute bile. The most likely cause for the different SE intensities of bile is the higher water content, and therefore longer T1 or T2 relaxation times, of hepatic bile. It is suggested that NMR imaging has the ability to provide physiological information about the gallbladder and that it may prove to be a simple and safe clinical test of gallbladder function.

  8. Proton nuclear magnetic resonance studies on brain edema

    SciTech Connect

    Naruse, S.; Horikawa, Y.; Tanaka, C.; Hirakawa, K.; Nishikawa, H.; Yoshizaki, K.

    1982-06-01

    The water in normal and edematous brain tissues of rats was studied by the pulse nuclear magnetic resonance (NMR) technique, measuring the longitudinal relaxation time (T1) and the transverse relaxation time (T2). In the normal brain, T1 and T2 were single components, both shorter than in pure water. Prolongation and separation of T2 into two components, one fast and one slow, were the characteristic findings in brain edema induced by both cold injury and triethyl tin (TET), although some differences between the two types of edema existed in the content of the lesion and in the degree of changes in T1 and T2 values. Quantitative analysis of T1 and T2 values in their time course relating to water content demonstrated that prolongation of T1 referred to the volume of increased water in tissues examined, and that two phases of T2 reflected the distribution and the content of the edema fluid. From the analysis of the slow component of T2 versus water content during edema formation, it was demonstrated that the increase in edema fluid was steady, and its content was constant during formation of TET-induced edema. On the contrary, during the formation of cold-injury edema, water-rich edema fluid increased during the initial few hours, and protein-rich edema fluid increased thereafter. It was concluded that proton NMR relaxation time measurements may provide new understanding in the field of brain edema research.

  9. Nuclear magnetic resonance imaging of the kidney: renal masses

    SciTech Connect

    Hricak, H.; Williams, R.D.; Moon, K.L. Jr.; Moss, A.A.; Alpers, C.; Crooks, L.E.; Kaufman, L.

    1983-06-01

    Fifteen patients with a variety of renal masses were examined by nuclear magnetic resonance (NMR), computed tomography, ultrasound, and intravenous urography. NMR clearly differentiated between simple renal cysts and other renal masses. On spin echo images, the simple renal cyst appeared as a round or slightly oval, homogeneous low-intensity mass with characteristically long T1 and T2 values. The thickness of the cyst wall was not measurable. The cyst had a smooth outer margin and a distict, sharp interface with normal parenchyma. Hemorrhagic cysts were seen as high-intensity lesions. Renal cell carcinomas displayed a wide range of intensity. The T1 and T2 values of the tumors were always different from those of the surrounding renal parenchyma. Tumor pseudocapsule was identified in four of five patients examined. All carcinomas were accurately staged by NMR and extension of the tumor thrombus into the inferior vena cava was demonstrated. The authors predict that if these preliminary results are confirmed by data from a larger number of patients, NMR will play a significant role in renal imaging.

  10. Monitoring iron mineralization processes using nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Keating, Kristina

    Proton nuclear magnetic resonance (NMR) measurements can be used to probe the molecular-scale physical and chemical environment of water in the pore space of geological materials. In geophysics, NMR relaxation measurements are used in to measure water content and estimate permeability in the top 100 m of Earth's surface. The goal of the research presented in this thesis is to determine if NMR can also be used in geophysical applications to monitor iron mineralization processes associated with contaminant remediation. The first part of the research presented in this thesis focuses on understanding the effect of iron mineral form and redox state on the NMR relaxation response of water in geologic material. Laboratory NMR measurements were made on Fe(III)-bearing minerals (ferrihydrite, lepidocrocite, goethite, and hematite), Fe(II)-bearing minerals (siderite, pyrite, and troilite), and a mixed valence iron-bearing mineral (magnetite). The results of these measurements show that the relaxation rate of water is strongly dependent on the mineral form of iron. Shown in the final section of this thesis are results from an experiment exploring temporal changes in the measured NMR relaxation rates during the reaction of ferrihydrite with aqueous Fe(II). These results show that NMR can be used to monitor temporal chemical changes in iron minerals. I conclude that this research shows that NMR indeed has the potential to be used as a tool for monitoring geochemical reactions associated with contaminant remediation.

  11. Conformational characterization of ceramides by nuclear magnetic resonance spectroscopy.

    PubMed Central

    Li, Li; Tang, Xiaoping; Taylor, K Grant; DuPré, Donald B; Yappert, M Cecilia

    2002-01-01

    Ceramide (Cer) has been identified as an active lipid second messenger in the regulation of cell growth, differentiation, and apoptosis. Its analog, dihydroceramide, without the 4 to 5 trans double bond in the sphingoid backbone lacks these biological effects. To establish the conformational features that distinguish ceramide from its analogs, nuclear magnetic resonance spectral data were acquired for diluted samples of ceramides (C2- and C18-Cer), dihydroceramide (C16-DHCer), and deoxydihydroceramide (C18-DODHCer). Our results suggest that in both C2- and C18-Cer, an H-bond network is formed in which the amide proton NH is donated to the OH groups on carbons C1 and C3 of the sphingosine backbone. Two tightly bound water molecules appear to stabilize this network by participating in flip-flop interactions with the hydroxyl groups. In DHCer, the lack of the trans double bond leads to a conformational distortion of this H-bonding motif. Without the critical double bond, the degree with which water molecules stabilize the H bonds between the two OH groups of the sphingolipid is reduced. This structural alteration might preclude the participation of DHCer in signaling-related interactions with cellular targets. PMID:11916863

  12. Nuclear resonance tomography with a toroid cavity detector

    DOEpatents

    Woelk, Klaus; Rathke, Jerome W.; Klingler, Robert J.

    1996-01-01

    A toroid cavity detection system for determining the spectral properties and distance from a fixed point for a sample using Nuclear Magnetic Resonance. The detection system consists of a toroid with a central conductor oriented along the main axis of the toroidal cylinder and perpendicular to a static uniform magnetic field oriented along the main axis of the toroid. An rf signal is inputted to the central conductor to produce a magnetic field perpendicular to the central axis of the toroid and whose field strength varies as the inverse of the radius of the toroid. The toroid cavity detection system can be used to encapsulate a sample, or the detection system can be perforated to allow a sample to flow into the detection device or to place the samples in specified sample tubes. The central conductor can also be coated to determine the spectral property of the coating and the coating thickness. The sample is then subjected to the respective magnetic fields and the responses measured to determine the desired properties.

  13. Multinuclear nuclear magnetic resonance spectroscopic study of cartilage proteoglycans

    SciTech Connect

    Lerner, L.

    1985-01-01

    Hyaline cartilage is a composite material whose major function is to withstand compression while retaining flexibility. Its mechanical properties are affected by tissue hydration and ionic composition. Models of the mechanical behavior of cartilage have incorporated certain assumptions about the interactions of the major components of cartilage: collagen, proteoglycans, water, and cations. To determine the validity of these assumption, the authors have used nuclear magnetic resonance spectroscopy (NMR). Two approaches have been used: (a) natural abundance carbon-13 NMR; and (b) NMR of sodium-23, potassium-39, magnesium-25, and calcium-43. Evidence from studies in intact tissues are reinforced by extensive measurements on solutions of proteoglycans and other relevant macromolecules. Based on the measurements of NMR relaxation rates and lineshapes reported here, it is concluded that neither sodium nor potassium interact strongly with bovine nasal proteoglycan aggregates or their substituent glycosaminoglycan chains in solution. Proteoglycans do bind magnesium and calcium. Therefore there is a qualitative difference between monovalent and divalent cations, which is not taken into account by polyelectrolyte models or models for the ionic dependence of mechanical properties. Cation binding to heparin, which has a higher charge density than cartilage proteoglycans, was also studied. The results presented here establish that heparin binds sodium, magnesium, and calcium.

  14. Nuclear Resonance Fluorescence for Material Verification in Dismantlement

    SciTech Connect

    Warren, Glen A.; Detwiler, Rebecca S.

    2011-10-01

    Nuclear resonance fluorescence (NRF) is a well-established physical process that provides an isotope-specific signature that can be exploited for isotopic detection and characterization of samples. Pacific Northwest National Laboratory has been investigating possible applications of NRF for national security. Of the investigated applications, the verification of material in the dismantlement process is the most promising. Through a combination of benchmarking measurements and radiation transport modeling, we have shown that NRF techniques with existing bremsstrahlung photon sources and a modest detection system can be used to detect highly enriched uranium in the quantities and time limits relevant to the dismantlement process. Issues such as orientation, placement and material geometry do not significantly impact the sensitivity of the technique. We have also investigated how shielding of the uranium would be observed through non-NRF processes to enable the accurate assay of the material. This paper will discuss our findings on how NRF and photon-interrogation techniques may be applied to the material verification in the dismantlement process.

  15. TOPICAL REVIEW: Spatial localization in nuclear magnetic resonance spectroscopy

    NASA Astrophysics Data System (ADS)

    Keevil, Stephen F.

    2006-08-01

    The ability to select a discrete region within the body for signal acquisition is a fundamental requirement of in vivo NMR spectroscopy. Ideally, it should be possible to tailor the selected volume to coincide exactly with the lesion or tissue of interest, without loss of signal from within this volume or contamination with extraneous signals. Many techniques have been developed over the past 25 years employing a combination of RF coil properties, static magnetic field gradients and pulse sequence design in an attempt to meet these goals. This review presents a comprehensive survey of these techniques, their various advantages and disadvantages, and implications for clinical applications. Particular emphasis is placed on the reliability of the techniques in terms of signal loss, contamination and the effect of nuclear relaxation and J-coupling. The survey includes techniques based on RF coil and pulse design alone, those using static magnetic field gradients, and magnetic resonance spectroscopic imaging. Although there is an emphasis on techniques currently in widespread use (PRESS, STEAM, ISIS and MRSI), the review also includes earlier techniques, in order to provide historical context, and techniques that are promising for future use in clinical and biomedical applications.

  16. Segmental Isotopic Labeling of Proteins for Nuclear Magnetic Resonance

    PubMed Central

    Dongsheng, Liu; Xu, Rong; Cowburn, David

    2009-01-01

    Nuclear Magnetic Resonance (NMR) spectroscopy has emerged as one of the principle techniques of structural biology. It is not only a powerful method for elucidating the 3D structures under near physiological conditions, but also a convenient method for studying protein-ligand interactions and protein dynamics. A major drawback of macromolecular NMR is its size limitation caused by slower tumbling rates and greater complexity of the spectra as size increases. Segmental isotopic labeling allows specific segment(s) within a protein to be selectively examined by NMR thus significantly reducing the spectral complexity for large proteins and allowing a variety of solution-based NMR strategies to be applied. Two related approaches are generally used in the segmental isotopic labeling of proteins: expressed protein ligation and protein trans-splicing. Here we describe the methodology and recent application of expressed protein ligation and protein trans-splicing for NMR structural studies of proteins and protein complexes. We also describe the protocol used in our lab for the segmental isotopic labeling of a 50 kDa protein Csk (C-terminal Src Kinase) using expressed protein ligation methods. PMID:19632474

  17. Theoretical and experimental studies in nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Roehrich, Adrienne M.

    Nuclear magnetic resonance (NMR) is a tool used to probe the physical and chemical environments of specific atoms in molecules. This research explored small molecule analogues to biological materials to determine NMR parameters using ab initio computations, comparing the results with solid-state NMR measurements. Models, such as dimethyl phosphate (DMP) for oligonucleotides or CuCl for the active site of the protein azurin, represented computationally unwieldy macromolecules. 31P chemical shielding tensors were calculated for DMP as a function of torsion angles, as well as for the phosphate salts, ammonium dihydrogen phosphate (ADHP), diammonium hydrogen phosphate, and magnesium dihydrogen phosphate. The computational DMP work indicated a problem with the current standard 31P reference of 85% H3PO 4(aq.). Comparison of the calculations and experimental spectra for the phosphate salts indicated ADHP might be a preferable alternative as a solid state NMR reference for 31P. Experimental work included magic angle spinning experiments on powder samples using the UNL chemistry department's Bruker Avance 600 MHz NMR to collect data to determine chemical shielding anisotropies. For the quadrupolar nuclei of copper and scandium, the electric field gradient was calculated in diatomic univalent metal halides, allowing determination of the minimal level of theory necessary to compute NMR parameters for these nuclei.

  18. Updated methodology for nuclear magnetic resonance characterization of shales.

    PubMed

    Washburn, Kathryn E; Birdwell, Justin E

    2013-08-01

    Unconventional petroleum resources, particularly in shales, are expected to play an increasingly important role in the world's energy portfolio in the coming years. Nuclear magnetic resonance (NMR), particularly at low-field, provides important information in the evaluation of shale resources. Most of the low-field NMR analyses performed on shale samples rely heavily on standard T1 and T2 measurements. We present a new approach using solid echoes in the measurement of T1 and T1-T2 correlations that addresses some of the challenges encountered when making NMR measurements on shale samples compared to conventional reservoir rocks. Combining these techniques with standard T1 and T2 measurements provides a more complete assessment of the hydrogen-bearing constituents (e.g., bitumen, kerogen, clay-bound water) in shale samples. These methods are applied to immature and pyrolyzed oil shale samples to examine the solid and highly viscous organic phases present during the petroleum generation process. The solid echo measurements produce additional signal in the oil shale samples compared to the standard methodologies, indicating the presence of components undergoing homonuclear dipolar coupling. The results presented here include the first low-field NMR measurements performed on kerogen as well as detailed NMR analysis of highly viscous thermally generated bitumen present in pyrolyzed oil shale.

  19. Polo-like kinase 2 gene expression is regulated by the orphan nuclear receptor estrogen receptor-related receptor gamma (ERR{gamma})

    SciTech Connect

    Park, Yun-Yong; Kim, Seok-Ho; Kim, Yong Joo; Kim, Sun Yee; Lee, Tae-Hoon; Lee, In-Kyu; Park, Seung Bum; Choi, Hueng-Sik

    2007-10-12

    Estrogen receptor-related receptor gamma (ERR{gamma}) is a member of the nuclear receptor family of transcriptional activators. To date, the target genes and physiological functions of ERR{gamma} are not well understood. In the current study, we identify that Plk2 is a novel target of ERR{gamma}. Northern blot analysis showed that overexpression of ERR{gamma} induced Plk2 expression in cancer cell lines. ERR{gamma} activated the Plk2 gene promoter, and deletion and mutational analysis of the Plk2 promoter revealed that the ERR{gamma}-response region is located between nucleotides (nt) -2327 and -2229 and -441 and -432 (relative to the transcriptional start site at +1). Electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) analysis demonstrated that ERR{gamma} binds directly to the Plk2 promoter. Overexpression of ERR{gamma} in the presence of the mitotic inhibitor nocodazole significantly decreased apoptosis, and induced S-phase cell cycle progression through the induction of Plk2 expression. Taken together, these results demonstrated that Plk2 is a novel target of ERR{gamma}, and suggest that this interaction is crucial for cancer cell proliferation.

  20. Gamma and neutron detection modeling in the nuclear detection figure of merit (NDFOM) portal

    SciTech Connect

    Stroud, Phillip D; Saeger, Kevin J

    2009-01-01

    The Nuclear Detection Figure Of Merit (NDFOM) portal is a database of objects and algorithms for evaluating the performance of radiation detectors to detect nuclear material. This paper describes the algorithms used to model the physics and mathematics of radiation detection. As a first-principles end-to-end analysis system, it starts with the representation of the gamma and neutron spectral fluxes, which are computed with the particle and radiation transport code MCNPX. The gamma spectra emitted by uranium, plutonium, and several other materials of interest are described. The impact of shielding and other intervening material is computed by the method of build-up factors. The interaction of radiation with the detector material is computed by a detector response function approach. The construction of detector response function matrices based on MCNPX simulation runs is described in detail. Neutron fluxes are represented in a three group formulation to treat differences in detector sensitivities to thermal, epithermal, and fast neutrons.

  1. Extension of nuclear structure data base searches for gamma-ray laser candidates

    SciTech Connect

    Arthur, E.D.; Madland, D.G.; George, D.C.

    1987-12-01

    Results from a data base search of computerized nuclear structure libraries have been extended and augmented so as to expand the information available for nuclei suitable as gamma-ray laser candidates. The spectrum of nuclear levels occurring in deformed rotational nuclei have been calculated and have been used in conjunction with isomeric state data for odd-A systems. The results of this augmentation effort are presented with particular emphasis on results obtained for /sup 177/Lu, /sup 177/Hf, and /sup 179/Hf. For these cases some possibly interesting cases were identified that met energy spacing criteria. However, significant hindrance factors exist for them which negate their interest for gamma-ray laser applications. 9 refs., 1 fig., 1 tab.

  2. MEMS-Based Force-Detected Nuclear Magnetic Resonance (FDNMR) Spectrometer

    NASA Technical Reports Server (NTRS)

    Lee, Choonsup; Butler, Mark C.; Elgammal, Ramez A.; George, Thomas; Hunt, Brian; Weitekamp, Daniel P.

    2006-01-01

    Nuclear Magnetic Resonance (NMR) spectroscopy allows assignment of molecular structure by acquiring the energy spectrum of nuclear spins in a molecule, and by interpreting the symmetry and positions of resonance lines in the spectrum. As such, NMR has become one of the most versatile and ubiquitous spectroscopic methods. Despite these tremendous successes, NMR experiments suffer from inherent low sensitivity due to the relatively low energy of photons in the radio frequency (rt) region of the electromagnetic spectrum. Here, we describe a high-resolution spectroscopy in samples with diameters in the micron range and below. We have reported design and fabrication of force-detected nuclear magnetic resonance (FDNMR).

  3. MEMS-Based Force-Detected Nuclear Magnetic Resonance (FDNMR) Spectrometer

    NASA Technical Reports Server (NTRS)

    Lee, Choonsup; Butler, Mark C.; Elgammal, Ramez A.; George, Thomas; Hunt, Brian; Weitekamp, Daniel P.

    2006-01-01

    Nuclear Magnetic Resonance (NMR) spectroscopy allows assignment of molecular structure by acquiring the energy spectrum of nuclear spins in a molecule, and by interpreting the symmetry and positions of resonance lines in the spectrum. As such, NMR has become one of the most versatile and ubiquitous spectroscopic methods. Despite these tremendous successes, NMR experiments suffer from inherent low sensitivity due to the relatively low energy of photons in the radio frequency (rt) region of the electromagnetic spectrum. Here, we describe a high-resolution spectroscopy in samples with diameters in the micron range and below. We have reported design and fabrication of force-detected nuclear magnetic resonance (FDNMR).

  4. Nuclear level densities and gamma-ray strength functions of 145,149,151Nd isotopes

    NASA Astrophysics Data System (ADS)

    Ay, K. O.; Ozgur, M.; Algin, E.; Guttormsen, M.; Bello Garrote, F. L.; Crespo Campo, L.; Görgen, A.; Hagen, T. W.; Ingeberg, V. W.; Kheswa, B. V.; Klintefjord, M.; Larsen, A. C.; Midtbo, J. E.; Modamio, V.; Renstrom, T.; Rose, S. J.; Sahin, E.; Siem, S.; Tveten, G. M.; Zeiser, F.

    2016-10-01

    The nuclear level densities and gamma-ray strength functions are the key elements for Hauser-Feshbach statistical model calculations to predict reaction cross sections which have many applications including astrophysics. The nuclear level densities and y-ray strength functions have been determined for 145,149,151Nd isotopes below the neutron separation energies using the Oslo method with the 144,148,150Nd(d,p) reactions. The results from the first measurements as well as planned experiments at OCL will be presented.

  5. An investigation of HPGe gamma efficiency calibration software (ANGLE V.3) for applications in nuclear decommissioning.

    PubMed

    Bell, S J; Judge, S M; Regan, P H

    2012-12-01

    High resolution gamma spectrometry offers a rapid method to characterise waste materials on a decommissioning nuclear site. To meet regulatory requirements, measurements must be traceable to national standards, meaning that the spectrometers must be calibrated for a wide range of materials. Semi-empirical modelling software (such as ANGLE™) offers a convenient method to carry out such calibrations. This paper describes an assessment of the modelling software for use by a small laboratory based on a nuclear site. The results confirmed the need for accurate information on the detection construction if the calibration were to be accurate to within 10%. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. Time stamp technique using a nuclear emulsion multi-stage shifter for gamma-ray telescope

    NASA Astrophysics Data System (ADS)

    Takahashi, Satoru; Aoki, Shigeki; Rokujo, Hiroki; Hamada, Kaname; Komatsu, Masahiro; Morishima, Kunihiro; Nakamura, Mitsuhiro; Nakano, Toshiyuki; Niwa, Kimio; Sato, Osamu; Yoshioka, Teppei; Kodama, Koichi

    2010-08-01

    Nuclear emulsion has a potential use as a gamma-ray telescope with high angular resolution. For this application it is necessary to know the time when each track was recorded in the emulsion. In previous experiments using nuclear emulsion, various efforts were used to associate time to nuclear emulsion tracks and to improve the time resolution. Using a high speed readout system for nuclear emulsion together with a clock-based multi-stage emulsion shifter, we invented a technique to give a time-stamp to emulsion tracks and greatly improve the time resolution. A test experiment with a 2-stage shifter was used to demonstrate the principle of multi-stage shifting, and we achieved a time resolution 1.5 s for 12.1 h (about 1 part in 29 000) with the time stamp reliability 97% and the time stamp efficiency 98%. This multi-stage shifter can achieve the time resolution required for a gamma-ray telescope and can also be applied to another cosmic ray observations and accelerator experiments using nuclear emulsion.

  7. Prompt gamma ray diagnostics and enhanced hadron-therapy using neutron-free nuclear reactions

    NASA Astrophysics Data System (ADS)

    Giuffrida, L.; Margarone, D.; Cirrone, G. A. P.; Picciotto, A.; Cuttone, G.; Korn, G.

    2016-10-01

    We propose a series of simulations about the potential use of Boron isotopes to trigger neutron-free (aneutronic) nuclear reactions in cancer cells through the interaction with an incoming energetic proton beam, thus resulting in the emission of characteristic prompt gamma radiation (429 keV, 718 keV and 1435 keV). Furthermore assuming that the Boron isotopes are absorbed in cancer cells, the three alpha-particles produced in each p-11B aneutronic nuclear fusion reactions can potentially result in the enhancement of the biological dose absorbed in the tumor region since these multi-MeV alpha-particles are stopped inside the single cancer cell, thus allowing to spare the surrounding tissues. Although a similar approach based on the use of 11B nuclei has been proposed in [Yoon et al. Applied Physics Letters 105, 223507 (2014)], our work demonstrate, using Monte Carlo simulations, the crucial importance of the use of 10B nuclei (in a solution containing also 11B) for the generation of prompt gamma-rays, which can be applied to medical imaging. In fact, we demonstrate that the use of 10B nuclei can enhance the intensity of the 718 keV gamma-ray peak more than 30 times compared to the solution containing only 11B nuclei. A detailed explanation of the origin of the different prompt gamma-rays, as well as of their application as real-time diagnostics during a potential cancer treatment, is here discussed.

  8. Nucleon-nucleon symmetry potential term and giant dipole resonance {gamma}-ray emission

    SciTech Connect

    Giuliani, G.; Papa, M.

    2006-03-15

    A study of the dependence of the giant dipole resonance {gamma}-ray yield from different functional forms of the symmetry term for the nucleon-nucleon interaction potential has been performed through the semiclassical molecular dynamics approach CoMD-II. We studied central and midperipheral reactions in the charge/mass asymmetric system {sup 40}Ca+{sup 48}Ca at 45 MeV/nucleon. The calculations show that the balance between the dynamical and the statistical emission is very sensitive to the 'stiffness' of the symmetry term. This sensitivity could be highlighted by measuring the degree of coherence and the anisotropy ratio related to the dynamically emitted radiation.

  9. Cut and paste RNA for nuclear magnetic resonance, paramagnetic resonance enhancement, and electron paramagnetic resonance structural studies.

    PubMed

    Duss, Olivier; Diarra Dit Konté, Nana; Allain, Frédéric H-T

    2015-01-01

    RNA is a crucial regulator involved in most molecular processes of life. Understanding its function at the molecular level requires high-resolution structural information. However, the dynamic nature of RNA complicates structure determination because crystallization is often not possible or can result in crystal-packing artifacts resulting in nonnative structures. To study RNA and its complexes in solution, we described an approach in which large multi-domain RNA or protein-RNA complex structures can be determined at high resolution from isolated domains determined by nuclear magnetic resonance (NMR) spectroscopy, and then constructing the entire macromolecular structure using electron paramagnetic resonance (EPR) long-range distance constraints. Every step in this structure determination approach requires different types of isotope or spin-labeled RNAs. Here, we present a simple modular RNA cut and paste approach including protocols to generate (1) small isotopically labeled RNAs (<10 nucleotides) for NMR structural studies, which cannot be obtained by standard protocols, (2) large segmentally isotope and/or spin-labeled RNAs for diamagnetic NMR and paramagnetic relaxation enhancement NMR, and (3) large spin-labeled RNAs for pulse EPR spectroscopy.

  10. Nuclear spin conversion of water inside fullerene cages detected by low-temperature nuclear magnetic resonance

    SciTech Connect

    Mamone, Salvatore Concistrè, Maria; Carignani, Elisa; Meier, Benno; Krachmalnicoff, Andrea; Johannessen, Ole G.; Denning, Mark; Carravetta, Marina; Whitby, Richard J.; Levitt, Malcolm H.; Lei, Xuegong; Li, Yongjun; Goh, Kelvin; Horsewill, Anthony J.

    2014-05-21

    The water-endofullerene H{sub 2}O@C{sub 60} provides a unique chemical system in which freely rotating water molecules are confined inside homogeneous and symmetrical carbon cages. The spin conversion between the ortho and para species of the endohedral H{sub 2}O was studied in the solid phase by low-temperature nuclear magnetic resonance. The experimental data are consistent with a second-order kinetics, indicating a bimolecular spin conversion process. Numerical simulations suggest the simultaneous presence of a spin diffusion process allowing neighbouring ortho and para molecules to exchange their angular momenta. Cross-polarization experiments found no evidence that the spin conversion of the endohedral H{sub 2}O molecules is catalysed by {sup 13}C nuclei present in the cages.

  11. Nuclear spin conversion of water inside fullerene cages detected by low-temperature nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Mamone, Salvatore; Concistrè, Maria; Carignani, Elisa; Meier, Benno; Krachmalnicoff, Andrea; Johannessen, Ole G.; Lei, Xuegong; Li, Yongjun; Denning, Mark; Carravetta, Marina; Goh, Kelvin; Horsewill, Anthony J.; Whitby, Richard J.; Levitt, Malcolm H.

    2014-05-01

    The water-endofullerene H2O@C60 provides a unique chemical system in which freely rotating water molecules are confined inside homogeneous and symmetrical carbon cages. The spin conversion between the ortho and para species of the endohedral H2O was studied in the solid phase by low-temperature nuclear magnetic resonance. The experimental data are consistent with a second-order kinetics, indicating a bimolecular spin conversion process. Numerical simulations suggest the simultaneous presence of a spin diffusion process allowing neighbouring ortho and para molecules to exchange their angular momenta. Cross-polarization experiments found no evidence that the spin conversion of the endohedral H2O molecules is catalysed by 13C nuclei present in the cages.

  12. Statistical Methods Applied to Gamma-ray Spectroscopy Algorithms in Nuclear Security Missions

    SciTech Connect

    Fagan, Deborah K.; Robinson, Sean M.; Runkle, Robert C.

    2012-10-01

    In a wide range of nuclear security missions, gamma-ray spectroscopy is a critical research and development priority. One particularly relevant challenge is the interdiction of special nuclear material for which gamma-ray spectroscopy supports the goals of detecting and identifying gamma-ray sources. This manuscript examines the existing set of spectroscopy methods, attempts to categorize them by the statistical methods on which they rely, and identifies methods that have yet to be considered. Our examination shows that current methods effectively estimate the effect of counting uncertainty but in many cases do not address larger sources of decision uncertainty—ones that are significantly more complex. We thus explore the premise that significantly improving algorithm performance requires greater coupling between the problem physics that drives data acquisition and statistical methods that analyze such data. Untapped statistical methods, such as Bayes Modeling Averaging and hierarchical and empirical Bayes methods have the potential to reduce decision uncertainty by more rigorously and comprehensively incorporating all sources of uncertainty. We expect that application of such methods will demonstrate progress in meeting the needs of nuclear security missions by improving on the existing numerical infrastructure for which these analyses have not been conducted.

  13. Nuclear Data Resources for Capture gamma-Ray Spectroscopy and Related Topics

    SciTech Connect

    Pritychenko, B.; Pritychenko,B.

    2011-08-18

    Nuclear reaction data play an important role in nuclear reactor, medical, and fundamental science and national security applications. The wealth of information is stored in internally adopted ENDF-6 and EXFOR formats. We present a complete calculation of resonance integrals, Westcott factors, thermal and Maxwellian-averaged cross sections for Z = 1-100 using evaluated nuclear reaction data. The addition of newly-evaluated neutron reaction libraries, and improvements in data processing techniques allows us to calculate nuclear industry and astrophysics parameters, and provide additional insights on all currently available neutron-induced reaction data. Nuclear reaction calculations will be discussed and an overview of the latest reaction data developments will be given.

  14. Development of a micro nuclear magnetic resonance system

    NASA Astrophysics Data System (ADS)

    Goloshevsky, Artem

    Application of Nuclear Magnetic Resonance (NMR) to on-line/in-line control of industrial processes is currently limited by equipment costs and requirements for installation. A superconducting magnet generating strong fields is the most expensive part of a typical NMR instrument. In industrial environments, fringe magnetic fields make accommodation of NMR instruments difficult. However, a portable, low-cost and low-field magnetic resonance system can be used in virtually any environment. Development of a number of hardware components for a portable, low-cost NMR instrument is reported in this dissertation. Chapter one provides a discussion on a miniaturized Helmholtz spiral radio-frequency (RF) coil (average diameter equal to 3.5 mm) and an NMR probe built around a capillary (outer diameter = 1.59 mm and inner diameter = 1.02 mm) for flow imaging. Experiments of NMR spectroscopy, static and dynamic (flow) imaging, conducted with the use of the miniaturized coil, are described. Chapter two presents a microfabricated package of two biaxial gradient coils and a Helmholtz RF coil. Planar configuration of discrete wires was used to create magnetic field gradients. Performance of the microfabricated gradient coils while imaging water flow compared well with a commercial gradient set of much larger size. Chapter three reports on flow imaging experiments with power law fluids (aqueous solutions of sodium salt of carboxymethyl cellulose (CMC)) of different viscosities, carried out in the NMR probe with the miniaturized RF coil and capillary. Viscosities of the CMC solutions were determined based on the curve fits of the velocity profiles and simultaneous measurements of the flow rates. The curve fits were carried out according to the power law model equations. The NMR viscosity measurements compared well with measurements of the same CMC samples, performed on a conventional rotational rheometer. A portable, home-built transceiver, designed for NMR applications utilizing a

  15. Experimental study of photon induced gamma emission of hafnium-178(m2) by nuclear spectroscopy methods

    NASA Astrophysics Data System (ADS)

    Zoita, Nicolae Catalin

    The induced release of the energy stored in nuclear isomers in the form of an incoherent gamma burst is of great scientific and technological importance. Powerful sources of induced gamma-ray radiation could be obtained, which would be an intermediary step to the development of a gamma-ray laser. High-energy nuclear isomers with very long lifetimes of the order of years and higher can serve as good active media. For instance, a macroscopic sample of 178Hfm2 isomer stores about 1 GJ/g as excitation energy of the isomeric state. Photonuclear reactions induced by real or virtual photons are the most promising mechanisms to release the energy stored by 178Hfm2 nuclei. The isomeric nucleus is excited to an intermediate level from which cascade to the ground state emitting gamma-photons. The nuclear level density approaches one per keV at those excitation energies. Experimental investigations by nuclear spectroscopy methods conducted in this work revealed that the decay of 178Hfm2 is accelerated when the energies of the incident photons were tuned at about 20,825 keV, 11.15 keV or near the L3 photoionization threshold of atomic hafnium at 9561 keV. In the first case, the presumed mechanism was the direct photoexcitation of the m2 isomeric nucleus to a trigger level at about 2466.9 keV. There was a strong decay branch from this trigger level to the 11- level of the 8 - band that caused the accelerated emission of gamma photons from many of the transitions detected in the unperturbed spontaneous decay. In the second case, a trigger level at about 2457.2 keV, that meant 11.15 keV above the 16+ isomeric level, was mediating the energy release. The direct transition from this level to ground state was observed. Other branches of its decay enhanced the gamma-emission of the ground state band (GSB) members. In the third case, complex electron bridging mechanisms were implied when incident X-ray photons were tuned at energies near the L3 photoionization threshold. Those

  16. Novel nuclear magnetic resonance techniques for studying biological molecules

    SciTech Connect

    Laws, David Douglas

    2000-06-01

    Over the fifty-five year history of Nuclear Magnetic Resonance (NMR), considerable progress has been made in the development of techniques for studying the structure, function, and dynamics of biological molecules. The majority of this research has involved the development of multi-dimensional NMR experiments for studying molecules in solution, although in recent years a number of groups have begun to explore NMR methods for studying biological systems in the solid-state. Despite this new effort, a need still exists for the development of techniques that improve sensitivity, maximize information, and take advantage of all the NMR interactions available in biological molecules. In this dissertation, a variety of novel NMR techniques for studying biomolecules are discussed. A method for determining backbone (Φ/Ψ) dihedral angles by comparing experimentally determined 13Ca, chemical-shift anisotropies with theoretical calculations is presented, along with a brief description of the theory behind chemical-shift computation in proteins and peptides. The utility of the Spin-Polarization Induced Nuclear Overhauser Effect (SPINOE) to selectively enhance NMR signals in solution is examined in a variety of systems, as are methods for extracting structural information from cross-relaxation rates that can be measured in SPINOE experiments. Techniques for the production of supercritical and liquid laser-polarized xenon are discussed, as well as the prospects for using optically pumped xenon as a polarizing solvent. In addition, a detailed study of the structure of PrP 89-143 is presented. PrP 89-143 is a 54 residue fragment of the prion proteins which, upon mutation and aggregation, can induce prion diseases in transgenic mice. Whereas the structure of the wild-type PrP 89-143 is a generally unstructured mixture of α-helical and β-sheet conformers in the solid state, the aggregates formed from the PrP 89-143 mutants appear to be mostly β-sheet.

  17. An evolution of technologies and applications of gamma imagers in the nuclear cycle industry

    SciTech Connect

    Khalil, R. A.; Menaa, N.; De Toro, D.; Varet, T.

    2011-07-01

    The tracking of radiation contamination and distribution has become a high priority in the nuclear cycle industry in order to respect the ALARA principle which is a main challenge during decontamination and dismantling activities. To support this need, AREVA/CANBERRA and CEA LIST have been actively carrying out research and development on a gamma-radiation imager. In this paper we will present the new generation of gamma camera, called GAMPIX. This system is based on the Timepix chip, hybridized with a CdTe substrate. A coded mask could be used in order to increase the sensitivity of the camera. Moreover, due to the USB connection with a standard computer, this gamma camera is immediately operational and user-friendly. The final system is a very compact gamma camera (global weight is less than 1 kg without any shielding) which could be used as a hand-held device for radioprotection purposes. In this article, we present the main characteristics of this new generation of gamma camera and we expose experimental results obtained during in situ measurements. Even though we present preliminary results the final product is under industrialization phase to address various applications specifications. (authors)

  18. Direct current superconducting quantum interference device spectrometer for pulsed nuclear magnetic resonance and nuclear quadrupole resonance at frequencies up to 5 MHz

    SciTech Connect

    TonThat, D.M.; Clarke, J. |

    1996-08-01

    A spectrometer based on a dc superconducting quantum interference device (SQUID) has been developed for the direct detection of nuclear magnetic resonance (NMR) or nuclear quadrupole resonance (NQR) at frequencies up to 5 MHz. The sample is coupled to the input coil of the niobium-based SQUID via a nonresonant superconducting circuit. The flux locked loop involves the direct offset integration technique with additional positive feedback in which the output of the SQUID is coupled directly to a low-noise preamplifier. Precession of the nuclear quadrupole spins is induced by a magnetic field pulse with the feedback circuit disabled; subsequently, flux locked operation is restored and the SQUID amplifies the signal produced by the nuclear free induction signal. The spectrometer has been used to detect {sup 27}Al NQR signals in ruby (Al{sub 2}O{sub 3}[Cr{sup 3+}]) at 359 and 714 kHz. {copyright} {ital 1996 American Institute of Physics.}

  19. Superconductivity and magnetic fluctuations in Cd(2))Re(2)O(7) via Cd nuclear magnetic resonance and re nuclear quadrupole resonance.

    PubMed

    Vyaselev, O; Arai, K; Kobayashi, K; Yamazaki, J; Kodama, K; Takigawa, M; Hanawa, M; Hiroi, Z

    2002-07-01

    We report Cd nuclear magnetic resonance (NMR) and Re nuclear quadrupole resonance (NQR) studies on Cd(2)Re(2)O(7), the first superconductor among pyrochlore oxides (T(c) approximately 1 K). The Re NQR spectrum at zero magnetic field below 100 K rules out any magnetic or charge order. The spin-lattice relaxation rate below T(c) exhibits a pronounced coherence peak and follows the weak-coupling BCS theory with nearly isotropic energy gap. The results of Cd NMR point to a moderate ferromagnetic enhancement at high temperatures followed by a rapid decrease of the density of states below the structural transition temperature of 200 K.

  20. Optically Pumped Nuclear Magnetic Resonance in the Quantum Hall Regimes

    NASA Astrophysics Data System (ADS)

    Barrett, Sean E.

    1998-03-01

    Optical pumping enables the direct detection of the nuclear magnetic resonance signal of ^71Ga nuclei located in an electron doped GaAs quantum well.footnote S. E. Barrett et al., Phys. Rev. Lett. 72, 1368 (1994) This OPNMR technique was previously used to measure the Knight shift (K_S)footnote S. E. Barrett et al., Phys. Rev. Lett. 74, 5112 (1995) and spin-lattice relaxation time (T_1)footnote R. Tycko et al., Science 268, 1460 (1995) near Landau level filling ν=1, which provided the first experimental support for the theoretical predictionsfootnote S. L. Sondhi et al., Phys. Rev. B 47, 16419 (1993); H. A. Fertig et al., Phys. Rev. B 50, 11018 (1994) that the charged excitations of the ν = 1 ground state are novel spin textures called skyrmions. We have recently demonstrated that OPNMR is possible in fields up to B=12 Tesla, and temperatures down to T= 0.3 K, making it a viable new probe of the Fractional Quantum Hall Regime. In this talk we will present our latest OPNMR measurements near Landau level filling ν=1/3, which include the first direct measurement of the electron spin polarization at ν=1/3. The spin polarization drops as the filling factor is varied away from ν=1/3, indicating that the quasiparticles and quasiholes are not fully spin-polarized. We will also show how the NMR lineshape away from ν=1/3 changes dramatically at low temperatures, which is due to slowing of the electron dynamics, and a reduction in the motional narrowing of the NMR line. The current understanding of these results will be discussed.

  1. Detecting body cavity bombs with nuclear quadrupole resonance

    NASA Astrophysics Data System (ADS)

    Collins, Michael London

    Nuclear Quadrupole Resonance (NQR) is a technology with great potential for detecting hidden explosives. Past NQR research has studied the detection of land mines and bombs concealed within luggage and packages. This thesis focuses on an NQR application that has received less attention and little or no publicly available research: detecting body cavity bombs (BCBs). BCBs include explosives that have been ingested, inserted into orifices, or surgically implanted. BCBs present a threat to aviation and secure facilities. They are extremely difficult to detect with the technology currently employed at security checkpoints. To evaluate whether or not NQR can be used to detect BCBs, a computational model is developed to assess how the dielectric properties of biological tissue affect the radio frequency magnetic field employed in NQR (0.5-5MHz). The relative permittivity of some biological tissue is very high (over 1,000 at 1MHz), making it conceivable that there is a significant effect on the electromagnetic field. To study this effect, the low-frequency approximation known as the Darwin model is employed. First, the electromagnetic field of a coil is calculated in free space. Second, a dielectric object or set of objects is introduced, and the free-space electric field is modified to accommodate the dielectric object ensuring that the relevant boundary conditions are obeyed. Finally, the magnetic field associated with the corrected electric field is calculated. This corrected magnetic field is evaluated with an NQR simulation to estimate the impact of dielectric tissue on NQR measurements. The effect of dielectric tissue is shown to be small, thus obviating a potential barrier to BCB detection. The NQR model presented may assist those designing excitation and detection coils for NQR. Some general coil design considerations and strategies are discussed.

  2. A Multidisciplinary Approach to High Throughput Nuclear Magnetic Resonance Spectroscopy

    PubMed Central

    Pourmodheji, Hossein; Ghafar-Zadeh, Ebrahim; Magierowski, Sebastian

    2016-01-01

    Nuclear Magnetic Resonance (NMR) is a non-contact, powerful structure-elucidation technique for biochemical analysis. NMR spectroscopy is used extensively in a variety of life science applications including drug discovery. However, existing NMR technology is limited in that it cannot run a large number of experiments simultaneously in one unit. Recent advances in micro-fabrication technologies have attracted the attention of researchers to overcome these limitations and significantly accelerate the drug discovery process by developing the next generation of high-throughput NMR spectrometers using Complementary Metal Oxide Semiconductor (CMOS). In this paper, we examine this paradigm shift and explore new design strategies for the development of the next generation of high-throughput NMR spectrometers using CMOS technology. A CMOS NMR system consists of an array of high sensitivity micro-coils integrated with interfacing radio-frequency circuits on the same chip. Herein, we first discuss the key challenges and recent advances in the field of CMOS NMR technology, and then a new design strategy is put forward for the design and implementation of highly sensitive and high-throughput CMOS NMR spectrometers. We thereafter discuss the functionality and applicability of the proposed techniques by demonstrating the results. For microelectronic researchers starting to work in the field of CMOS NMR technology, this paper serves as a tutorial with comprehensive review of state-of-the-art technologies and their performance levels. Based on these levels, the CMOS NMR approach offers unique advantages for high resolution, time-sensitive and high-throughput bimolecular analysis required in a variety of life science applications including drug discovery. PMID:27294925

  3. Advances in Theory of Solid-State Nuclear Magnetic Resonance

    PubMed Central

    Mananga, Eugene S.; Moghaddasi, Jalil; Sana, Ajaz; Akinmoladun, Andrew; Sadoqi, Mostafa

    2015-01-01

    Recent advances in theory of solid state nuclear magnetic resonance (NMR) such as Floquet-Magnus expansion and Fer expansion, address alternative methods for solving a time-dependent linear differential equation which is a central problem in quantum physics in general and solid-state NMR in particular. The power and the salient features of these theoretical approaches that are helpful to describe the time evolution of the spin system at all times are presented. This review article presents a broad view of manipulations of spin systems in solid-state NMR, based on milestones theories including the average Hamiltonian theory and the Floquet theory, and the approaches currently developing such as the Floquet-Magnus expansion and the Fer expansion. All these approaches provide procedures to control and describe the spin dynamics in solid-state NMR. Applications of these theoretical methods to stroboscopic and synchronized manipulations, non-synchronized experiments, multiple incommensurated frequencies, magic-angle spinning samples, are illustrated. We also reviewed the propagators of these theories and discussed their convergences. Note that the FME is an extension of the popular Magnus Expansion and Average Hamiltonian Theory. It aims is to bridge the AHT to the Floquet Theorem but in a more concise and efficient formalism. Calculations can then be performed in a finite-dimensional Hilbert space instead of an infinite dimensional space within the so-called Floquet theory. We expected that the FME will provide means for more accurate and efficient spin dynamics simulation and for devising new RF pulse sequence. PMID:26878063

  4. A Multidisciplinary Approach to High Throughput Nuclear Magnetic Resonance Spectroscopy.

    PubMed

    Pourmodheji, Hossein; Ghafar-Zadeh, Ebrahim; Magierowski, Sebastian

    2016-06-09

    Nuclear Magnetic Resonance (NMR) is a non-contact, powerful structure-elucidation technique for biochemical analysis. NMR spectroscopy is used extensively in a variety of life science applications including drug discovery. However, existing NMR technology is limited in that it cannot run a large number of experiments simultaneously in one unit. Recent advances in micro-fabrication technologies have attracted the attention of researchers to overcome these limitations and significantly accelerate the drug discovery process by developing the next generation of high-throughput NMR spectrometers using Complementary Metal Oxide Semiconductor (CMOS). In this paper, we examine this paradigm shift and explore new design strategies for the development of the next generation of high-throughput NMR spectrometers using CMOS technology. A CMOS NMR system consists of an array of high sensitivity micro-coils integrated with interfacing radio-frequency circuits on the same chip. Herein, we first discuss the key challenges and recent advances in the field of CMOS NMR technology, and then a new design strategy is put forward for the design and implementation of highly sensitive and high-throughput CMOS NMR spectrometers. We thereafter discuss the functionality and applicability of the proposed techniques by demonstrating the results. For microelectronic researchers starting to work in the field of CMOS NMR technology, this paper serves as a tutorial with comprehensive review of state-of-the-art technologies and their performance levels. Based on these levels, the CMOS NMR approach offers unique advantages for high resolution, time-sensitive and high-throughput bimolecular analysis required in a variety of life science applications including drug discovery.

  5. Advances in Theory of Solid-State Nuclear Magnetic Resonance.

    PubMed

    Mananga, Eugene S; Moghaddasi, Jalil; Sana, Ajaz; Akinmoladun, Andrew; Sadoqi, Mostafa

    Recent advances in theory of solid state nuclear magnetic resonance (NMR) such as Floquet-Magnus expansion and Fer expansion, address alternative methods for solving a time-dependent linear differential equation which is a central problem in quantum physics in general and solid-state NMR in particular. The power and the salient features of these theoretical approaches that are helpful to describe the time evolution of the spin system at all times are presented. This review article presents a broad view of manipulations of spin systems in solid-state NMR, based on milestones theories including the average Hamiltonian theory and the Floquet theory, and the approaches currently developing such as the Floquet-Magnus expansion and the Fer expansion. All these approaches provide procedures to control and describe the spin dynamics in solid-state NMR. Applications of these theoretical methods to stroboscopic and synchronized manipulations, non-synchronized experiments, multiple incommensurated frequencies, magic-angle spinning samples, are illustrated. We also reviewed the propagators of these theories and discussed their convergences. Note that the FME is an extension of the popular Magnus Expansion and Average Hamiltonian Theory. It aims is to bridge the AHT to the Floquet Theorem but in a more concise and efficient formalism. Calculations can then be performed in a finite-dimensional Hilbert space instead of an infinite dimensional space within the so-called Floquet theory. We expected that the FME will provide means for more accurate and efficient spin dynamics simulation and for devising new RF pulse sequence.

  6. Search for the electromagnetic decay of {Delta}(1232) resonance in nuclear matter

    SciTech Connect

    Badala, A.; Barbera, R.; Gulino, M.; Palmeri, A.; Pappalardo, G.S.; Riggi, F.; Russo, A.C.; Russo, G.; Turrisi, R.; Barbera, R.; Gulino, M.; Riggi, F.; Russo, G.; Turrisi, R.; Bonasera, A.

    1998-01-01

    In order to inquire into the existence and significance of non-nucleonic degrees of freedom in the intermediate-energy regime, the production of protons and high-energy photons (E{sub {gamma}}{gt}30 MeV) emitted in the reaction {sup 36}Ar+{sup 27}Al at 95 MeV/nucleon has been studied. The quantitative analysis of the ({gamma}-p) invariant-mass and relative-angle distributions shows evidences of {Delta}(1232)-resonance excitation and {Delta}{r_arrow}N{gamma} decay. Experimental data are in agreement with microscopic theoretical calculations. {copyright} {ital 1998} {ital The American Physical Society}

  7. Study of natural diamonds by dynamic nuclear polarization-enhanced 13C nuclear magnetic resonance spectroscopy.

    PubMed

    Zhou, J; Li, L; Hu, H; Yang, B; Dan, Z; Qiu, J; Guo, J; Chen, F; Ye, C

    1994-11-01

    The results of a study of two types of natural-diamond crystals by dynamic nuclear polarization (DNP)-enhanced high-resolution solid-state 13C nuclear magnetic resonance (NMR) are reported. The home-built DNP magic-angle spinning (MAS) 13C NMR spectrometer operates at 54 GHz for electrons and 20.2 MHz for carbons. The power of the microwave source was about 30 W and the highest DNP enhancement factor came near to 10(3). It was shown that in the MAS spectra the 13C NMR linewidths of the Ib-type diamond were broader than those of IaB3-type diamond. From the hyperfine structure of the DNP enhancement as a function of frequency, four kinds of nitrogen-centred and one kind of carbon-centred free radicals could be identified in the Ib-type diamond. The hyperfine structures of the DNP enhancement curve that originated from the anisotropic hyperfine interaction between electron and nuclei could be partially averaged out by MAS. The 13C polarization time of DNP was rather long, i.e. 1500 s, and the spin-lattice relaxation time (without microwave irradiation) was about 300 s, which was somewhat shorter than anticipated. Discussions on these experimental results have been made in this report.

  8. New frontiers in nuclear physics with high-power lasers and brilliant monochromatic gamma beams

    NASA Astrophysics Data System (ADS)

    Gales, S.; Balabanski, D. L.; Negoita, F.; Tesileanu, O.; Ur, C. A.; Ursescu, D.; Zamfir, N. V.

    2016-09-01

    The development of high power lasers and the combination of such novel devices with accelerator technology has enlarged the science reach of many research fields, in particular particle and nuclear physics, astrophysics as well as societal applications in material science, nuclear energy and applications for medicine. The European Strategic Forum for Research Infrastructures has selected a proposal based on these new premises called the Extreme Light Infrastructure (ELI). The ELI will be built as a network of three complementary pillars at the frontier of laser technologies. The ELI-NP pillar (NP for nuclear physics) is under construction near Bucharest (Romania) and will develop a scientific program using two 10 PW lasers and a Compton back-scattering high-brilliance and intense low-energy gamma beam, a combination of laser and accelerator technology at the frontier of knowledge. This unique combination of beams that are unique worldwide allows us to develop an experimental program in nuclear physics at the frontiers of present-day knowledge as well as society driven applications. In the present paper, the technical description of the facility as well as the new perspectives in nuclear structure, nuclear reactions and nuclear astrophysics will be presented.

  9. Extreme nuclear shapes examined via giant dipole resonance lineshapes in hot light-mass systems

    SciTech Connect

    Pandit, Deepak; Mukhopadhyay, S.; Pal, Surajit; Bhattacharya, S.; Bhattacharya, C.; Banerjee, K.; Kundu, S.; Rana, T. K.; Dey, A.; Mukherjee, G.; Ghosh, T.; Banerjee, S. R.; De, A.; Gupta, D.

    2010-06-15

    The influence of alpha clustering on nuclear reaction dynamics is investigated using the giant dipole resonance (GDR) lineshape studies in the reactions {sup 20}Ne (E{sub lab}=145,160 MeV) + {sup 12}C and {sup 20}Ne (E{sub lab}=160 MeV) + {sup 27}Al, populating {sup 32}S and {sup 47}V, respectively. The GDR lineshapes from the two systems are remarkably different from each other. Whereas, the non-alpha-like {sup 47}V undergoes Jacobi shape transition and matches exceptionally well with the theoretical GDR lineshape estimated under the framework rotating liquid drop model (RLDM) and thermal shape fluctuation model (TSFM) signifying shape equilibration, for the alpha cluster {sup 32}S an extended prolate kind of shape is observed. This unusual deformation, seen directly via gamma decay for the first time, is predicted to be due to the formation of orbiting dinuclear configuration or molecular structure of {sup 16}O + {sup 16}O in the {sup 32}S superdeformed band.

  10. Gated in vivo examination of cardiac metabolites with /sup 31/P nuclear magnetic resonance

    SciTech Connect

    Kantor, H.L.; Briggs, R.W.; Metz, K.R.; Balaban, R.S.

    1986-07-01

    Phosphorus-31 nuclear magnetic resonance (/sup 31/P NMR) spectroscopy was used to study the temporal aspects of metabolism of canine heart in vivo. An NMR catheter coil was passed through the jugular vein of a dog into the apex of the right ventricle and spectra were recorded at four points in the cardiac cycle by triggering from the blood pressure trace of the animal. The /sup 31/P spin-lattice relaxation times of phosphocreatine (PC) and the ..gamma../sup -/,..cap alpha../sup -/, and ..beta..-phosphates of ATP at 1.89 Tesla are 4.4, 1.8, 1.7, and 1.6 s, respectively. The ratio of PC to ATP is 2.0. No changes in PC/ATP were noted in any of the four portions of the cardiac cycle examined, and difference spectra exhibited no observable signals, in contrast to previously reported results for glucose-perfused rat hearts. On the assumption that intracellular pH and the total creatine pool were constant, the expression for the creatine kinase reaction was used to deduce that free ADP concentrations were invariant throughout the cardiac cycle. This is in apparent disagreement with the proposed regulatory role for ADP in heart oxidative phosphorylation.

  11. Nuclear magnetic resonance data of C2H10OSi2

    NASA Astrophysics Data System (ADS)

    Mikhova, B. M.

    This document is part of Part 6 `Organic Metalloid Compounds' of Subvolume D 'Chemical Shifts and Coupling Constants for Carbon-13' of Landolt-Börnstein III/35 'Nuclear Magnetic Resonance Data', Group III 'Condensed Matter'.

  12. Nuclear magnetic resonance data of C8H24OSi4Te

    NASA Astrophysics Data System (ADS)

    Mikhova, B. M.

    This document is part of Part 6 `Organic Metalloid Compounds' of Subvolume D 'Chemical Shifts and Coupling Constants for Carbon-13' of Landolt-Börnstein III/35 'Nuclear Magnetic Resonance Data', Group III 'Condensed Matter'.

  13. Two-Dimensional Isotope Imaging of Radiation Shielded Materials Using Nuclear Resonance Fluorescence

    NASA Astrophysics Data System (ADS)

    Toyokawa, Hiroyuki; Ohgaki, Hideaki; Hayakawa, Takehito; Kii, Toshiteru; Shizuma, Toshiyuki; Hajima, Ryoichi; Kikuzawa, Nobuhiro; Masuda, Kai; Kitatani, Fumito; Harada, Hideo

    2011-10-01

    A novel method for two-dimensional (2D) imaging of a specific isotope in a material, which is hidden by a thick radiation shield is presented. Nuclear resonance fluorescence and the laser Compton scattering are used in the present method. We measured γ-rays of 5512 keV from the nuclear resonance fluorescence of 208Pb at several points, and obtained a 2D image of isotope distribution.

  14. Spin and Parity Assignment of Neutron Resonances using Gamma-ray Multiplicity

    SciTech Connect

    Agvaanluvsan, U.; Mitchell, G. E.; Baramsai, B.; Chyzh, A.; Walker, C.; Dashdorj, D.; Becker, J. A.; Parker, W. E.; Sleaford, B.; Wu, C. Y.; Bredeweg, T. A.; Couture, A.; Haight, R. C.; Jandel, M.; Rundberg, R. S.; Ullmann, J. L.; Vieira, D. J.; Wouters, J. M.; Krticka, M.; Becvar, F.

    2009-03-31

    Decay gamma rays following neutron capture on various isotopes are collected by the Detector for Advanced Neutron Capture Experiments (DANCE) array, which is located at flight path 14 at the Lujan Neutron Scattering Center at Los Alamos National Laboratory. The high segmentation (160 detectors) and close packing of the detector array enable gamma-ray multiplicity measurements. The calorimetric properties of the DANCE array coupled with the neutron time-of-flight technique enables one to gate on a specific resonance of a given isotope in the time-of-flight spectrum and obtain the summed energy spectrum for that isotope. The singles gamma-ray spectrum for each multiplicity can be separated by their DANCE cluster multiplicity. The multiplicity distribution contains the signatures of spin and parity of the capture state. Under suitable circumstances where the difference between spins of the initial (capture) and final (ground) state is large enough, the signatures in the multiplicity distribution can be used in improving the spin assignment of the initial state. The spin assignment is applied with varying degree of success to difference isotopes and description of this application for {sup 95}Mo, {sup 151,153}Eu, and {sup 155,157}Gd is reviewed briefly.

  15. Electron paramagnetic resonance of natural and gamma-irradiated alunite and kaolin mineral powders

    NASA Astrophysics Data System (ADS)

    Koksal, F.; Koseoglu, R.; Saka, I.; Basaran, E.; Sener, F.

    2004-06-01

    Natural alunite and kaolin minerals obtained from West Anatolia were investigated by electron paramagnetic resonance (EPR) in natural and gamma-irradiated states at room temperature and at 113 K. The paramagnetic centres at ambient temperature in natural alunite were attributed to the (C) over dot H 2OH, (C) over dot O-3(-), (S) over dot O-2(-), (C) over dot O-2(-) and [AlO4 ](0) radicals. In natural kaolin, the paramagnetic centres were attributed to the (C) over dot O-3(-), (S) over dot O-2(-) (C) over dot O-2(-) and [AlO4](0) radicals. The gamma-irradiation does not produce any detectable effects on these radicals. At 113 K, the lines for (C) over dot H2OH could not be observed well, probably due to the anisotropic behaviour of the hyperfine interaction of the methylene protons, but the lines for [AlO4](0) centres were found to be perfectly observable at above 20 mW microwave power in both alunite and kaolin powders before and after gamma-irradiation. The EPR parameters of the observed paramagnetic centres were reported.

  16. Intense {gamma}-Ray Source in the Giant-Dipole-Resonance Range Driven by 10-TW Laser Pulses

    SciTech Connect

    Giulietti, A.; Gamucci, A.; Gizzi, L. A.; Labate, L.; Bourgeois, N.; Marques, J. R.; Ceccotti, T.; Dobosz, S.; D'Oliveira, P.; Monot, P.; Popescu, H.; Reau, F.; Martin, P.; Galy, J.; Hamilton, D. J.; Giulietti, D.

    2008-09-05

    A {gamma}-ray source with an intense component around the giant dipole resonance for photonuclear absorption has been obtained via bremsstrahlung of electron bunches driven by a 10-TW tabletop laser. 3D particle-in-cell simulation proves the achievement of a nonlinear regime leading to efficient acceleration of several sequential electron bunches per each laser pulse. The rate of the {gamma}-ray yield in the giant dipole resonance region (8gamma}}<17.5 MeV) was measured, through the radio activation of a gold sample, to be 4x10{sup 8} photons per joule of laser energy. This novel all-optical, compact, and efficient electron-{gamma} source is suitable for photonuclear studies and medical uses.

  17. Hairpin structures in DNA containing arabinofuranosylcytosine. A combination of nuclear magnetic resonance and molecular dynamics

    SciTech Connect

    Pieters, J.M.L.; de Vroom, E.; van der Marel, G.A.; van Boom, J.H.; Altona, C. ); Koning, T.H.G.; Kaptein, R. )

    1990-01-23

    Nuclear magnetic resonance (NMR) and model-building studies were carried out on the hairpin form of the octamer d(CG{sup a}CTAGCG) ({sup a}C = arabinofuranosylcytosine), referred to as the TA compound. The nonexchangeable protons of the TA compound were assigned by means of nuclear Overhauser effect spectroscopy (NOESY) and correlated spectroscopy (COSY). Form a detailed analysis of the coupling data and of the NOESY spectra the following conclusions are reached: (i) the hairpin consists of a stem of three Watson-Crick type base pairs, and the two remaining residues, T(4) and dA(5), participate in a loop. (ii) All sugar rings show conformational flexibility although a strong preference for the S-type (C2{prime}-endo) conformer is observed. (iii) The thymine does not stack upon the 3{prime} side of the stem as expected, but swings into the minor groove. (iv) At the 5{prime}-3{prime} loop-stem junction a stacking discontinuity occurs as a consequence of a sharp turn in that part of the backbone, caused by the unusual {beta}{sup +} and {gamma}{sup t} torsion angles in residue dG(6). (v) The A base slides over the 5{prime} side of the stem to stack upon the {sup a}C(3) residue at the 3{prime} side of the stem in an antiparallel fashion. On the basis of J couplings and a set approximate proton-proton distances from NOE cross peaks, a model for the hairpin was constructed.

  18. Delayed gamma-ray spectroscopy combined with active neutron interrogation for nuclear security and safeguards

    NASA Astrophysics Data System (ADS)

    Koizumi, Mitsuo; Rossi, Fabiana; Rodriguez, Douglas C.; Takamine, Jun; Seya, Michio; Bogucarska, Tatjana; Crochemore, Jean-Michel; Varasano, Giovanni; Abbas, Kamel; Pederson, Bent; Kureta, Masatoshi; Heyse, Jan; Paradela, Carlos; Mondelaers, Willy; Schillebeeckx, Peter

    2017-09-01

    For the purpose of nuclear security and safeguards, an active neutron interrogation non-destructive assay technique, Delayed Gamma-ray Spectroscopy (DGS), is under development. The technique of DGS uses the detection of decay γ rays from fission products to determine ratios of fissile nuclides in a sample. A proper evaluation of such γ-ray spectra requires integration of nuclear data such as fission cross-sections, fission yields, half-lives, decay-chain patterns, and decay γ-ray yields. Preliminary DGS experiments with the Pulsed Neutron Interrogation Test Assembly, named PUNITA, of the European Commissions' Joint Research Center have been performed. Signals of delayed γ ray from nuclear materials were successfully observed.

  19. Inter-laboratory comparisons of short-lived gamma-emitting radionuclides in nuclear reactor water.

    PubMed

    Klemola, S K

    2008-01-01

    Inter-laboratory comparisons of gamma-emitting nuclides in nuclear power plant coolant water have been carried out in Finland since 1994. The reactor water samples are taken and prepared by one of the two nuclear power plants and delivered to the participants. Since all the participants get their sample within just a few hours it has been possible to analyse and compare results of nuclides with half-lives shorter than 1h. The total number of short-lived nuclides is 26. All the main nuclides are regularly identified and the activities have been obtained with reasonable accuracy throughout the years. The overall deviation of the results has decreased in 13 years. The effects of true coincidence summing and discrepancies in nuclear data have been identified as potential sources of remaining discrepancies. All the participants have found this type of comparison very useful.

  20. {sup 57}Co(n,{gamma}){sup 58}Co reaction cross section: Thermal and resonance integral measurements and energy dependence

    SciTech Connect

    Maidana, Nora L.; Mesa, Joel; Vanin, Vito R.; Castro, Ruy M.; Dias, Mauro S.; Koskinas, Marina F.

    2004-07-01

    The {sup 57}Co(n,{gamma}){sup 58}Co thermal and resonance integral cross section were measured as 51(5) b and 20.0(19) b, respectively, by irradiating aliquots of {sup 57}Co solution sealed inside quartz bottles near the core of the IEA-R1 IPEN research reactor and counting the gamma-ray residual activity. The irradiations were monitored using Au-Al alloy foils, with and without Cd cover. The gamma-ray measurements were performed with a shielded HPGe detector. Westcott formalism was applied for the average neutron flux determination. The cross section energy dependence was evaluated using the multilevel Breit-Wigner expression considering the first two resonances and the statistical model for energies above the second resonance. Maxwellian averaged neutron capture cross section with neutron temperatures between 5 and 100 keV were also evaluated.

  1. Neutron Resonance Theory for Nuclear Reactor Applications: Modern Theory and Practices.

    SciTech Connect

    Hwang, Richard N.; Blomquist, Roger N.; Leal, Luiz C.; Yang, Won Sik

    2016-09-24

    The neutron resonance phenomena constitute one of the most fundamental subjects in nuclear physics as well as in reactor physics. It is the area where the concepts of nuclear interaction and the treatment of the neutronic balance in reactor fuel lattices become intertwined. The latter requires the detailed knowledge of resonance structures of many nuclides of practical interest to the development of nuclear energy. The most essential element in reactor physics is to provide an accurate account of the intricate balance between the neutrons produced by the fission process and neutrons lost due to the absorption process as well as those leaking out of the reactor system. The presence of resonance structures in many major nuclides obviously plays an important role in such processes. There has been a great deal of theoretical and practical interest in resonance reactions since Fermi’s discovery of resonance absorption of neutrons as they were slowed down in water. The resonance absorption became the center of attention when the question was raised as to the feasibility of the self-sustaining chain reaction in a natural uranium-fueled system. The threshold of the nuclear era was crossed almost eighty years ago when Fermi and Szilard observed that a substantial reduction in resonance absorption is possible if the uranium was made into the form of lumps instead of a homogeneous mixture with water. In the West, the first practical method for estimating the resonance escape probability in a reactor cell was pioneered by Wigner et al in early forties.

  2. Structural Isomer Identification via NMR: A Nuclear Magnetic Resonance Experiment for Organic, Analytical, or Physical Chemistry.

    ERIC Educational Resources Information Center

    Szafran, Zvi

    1985-01-01

    Background information, procedures used, and typical results obtained are provided for an experiment that examines the ability of nuclear magnetic resonance (NMR) to distinguish between structural isomers via resonance multiplicities and chemical shifts. Reasons for incorporating the experiment into organic, analytical, or physical chemistry…

  3. Structural Isomer Identification via NMR: A Nuclear Magnetic Resonance Experiment for Organic, Analytical, or Physical Chemistry.

    ERIC Educational Resources Information Center

    Szafran, Zvi

    1985-01-01

    Background information, procedures used, and typical results obtained are provided for an experiment that examines the ability of nuclear magnetic resonance (NMR) to distinguish between structural isomers via resonance multiplicities and chemical shifts. Reasons for incorporating the experiment into organic, analytical, or physical chemistry…

  4. REVEALING TYPE Ia SUPERNOVA PHYSICS WITH COSMIC RATES AND NUCLEAR GAMMA RAYS

    SciTech Connect

    Horiuchi, Shunsaku; Beacom, John F. E-mail: beacom@mps.ohio-state.ed

    2010-11-01

    Type Ia supernovae (SNe Ia) remain mysterious despite their central importance in cosmology and their rapidly increasing discovery rate. The progenitors of SNe Ia can be probed by the delay time between progenitor birth and explosion as SNe Ia. The explosions and progenitors of SNe Ia can be probed by MeV nuclear gamma rays emitted in the decays of radioactive nickel and cobalt into iron. We compare the cosmic star formation and SN Ia rates, finding that their different redshift evolution requires a large fraction of SNe Ia to have large delay times. A delay-time distribution of the form t {sup -}{alpha} with {alpha} = 1.0 {+-} 0.3 provides a good fit, implying that 50% of SNe Ia explode more than {approx}1 Gyr after progenitor birth. The extrapolation of the cosmic SN Ia rate to z = 0 agrees with the rate we deduce from catalogs of local SNe Ia. We investigate prospects for gamma-ray telescopes to exploit the facts that escaping gamma rays directly reveal the power source of SNe Ia and uniquely provide tomography of the expanding ejecta. We find large improvements relative to earlier studies by Gehrels et al. in 1987 and Timmes and Woosley in 1997 due to larger and more certain SN Ia rates and advances in gamma-ray detectors. The proposed Advanced Compton Telescope, with a narrow-line sensitivity {approx}60 times better than that of current satellites, would, on an annual basis, detect up to {approx}100 SNe Ia (3{sigma}) and provide revolutionary model discrimination for SNe Ia within 20 Mpc, with gamma-ray light curves measured with {approx}10{sigma} significance daily for {approx}100 days. Even more modest improvements in detector sensitivity would open a new and invaluable astronomy with frequent SN Ia gamma-ray detections.

  5. Improving the Assay of 239Pu in Spent and Melted Fuel Using the Nuclear Resonance Fluorescence Integral Resonance Transmission Method

    NASA Astrophysics Data System (ADS)

    Angell, C. T.; Hayakawa, T.; Shizuma, T.; Hajima, R.; Quiter, B. J.; Ludewigt, B. A.; Karwowski, H.; Rich, G.

    2015-10-01

    Non-destructive assay (NDA) of 239Pu in spent nuclear fuel is possible using the isotope-specific nuclear resonance fluorescence (NRF) integral resonance transmission (IRT) method. The IRT method measures the absorption of photons from a quasi-monoenergetic γ-ray beam due to all resonances in the energy width of the beam. According to calculations the IRT method could greatly improve assay times for 239Pu in nuclear fuel. To demonstrate and verify the IRT method, the IRT signature was first measured in 181Ta, whose nuclear resonant properties are similar to those of 239Pu, and then measured in 239Pu. These measurements were done using the quasi-monoenergetic beam at the High Intensity γ-ray Source (HIγS) in Durham, NC, USA. The IRT signature was observed as a decrease in scattering strength when the same isotope material was placed upstream of the scattering target. The results confirm the validity of the IRT method in both 181Ta and 239Pu.

  6. Nuclear cascades in electromagnetic showers produced by primary gamma-quanta in the atmosphere

    NASA Technical Reports Server (NTRS)

    Danilova, T. V.; Erlykin, A. D.; Mironov, A. V.; Tukish, E. I.

    1985-01-01

    Distributions were calculated for the number of electrons N sub e, number of muons with the energy above 5 GeV N sub mu and the energy of hadron component E sub h in electromagnetic showers, produced by primary gamma-quanta with energies theta approx. equals 30 deg and observed at the mountain level 700 g/square centimeters. The mean number of nuclear interactions of photos with the energy above 5 GeV is about 0.3 per each TeV of the primary energy and nuclear cascades take out in average about 2% of the total shower energy. The mean number of 5 GeV muons for the electromagnetic shower is (2 to 5)% from the number of muons in cosmic ray showers with the same number of electrons at the observation level. similar value for the total energy of hadron component is also (2 to 5)%. N sub mu and N sub e values as well as E sub h and n sub e don't correlate at the fixed primary energy E sug gamma (o). Between N sub mu and E sub h there is a positive correlation at the given E sub gamma.

  7. CREB controls hepatic lipid metabolism through nuclear hormone receptor PPAR-gamma.

    PubMed

    Herzig, Stephan; Hedrick, Susan; Morantte, Ianessa; Koo, Seung-Hoi; Galimi, Francesco; Montminy, Marc

    2003-11-13

    Fasting triggers a series of hormonal cues that promote energy balance by inducing glucose output and lipid breakdown in the liver. In response to pancreatic glucagon and adrenal cortisol, the cAMP-responsive transcription factor CREB activates gluconeogenic and fatty acid oxidation programmes by stimulating expression of the nuclear hormone receptor coactivator PGC-1 (refs 2-5). In parallel, fasting also suppresses lipid storage and synthesis (lipogenic) pathways, but the underlying mechanism is unknown. Here we show that mice deficient in CREB activity have a fatty liver phenotype and display elevated expression of the nuclear hormone receptor PPAR-gamma, a key regulator of lipogenic genes. CREB inhibits hepatic PPAR-gamma expression in the fasted state by stimulating the expression of the Hairy Enhancer of Split (HES-1) gene, a transcriptional repressor that is shown here to be a mediator of fasting lipid metabolism in vivo. The coordinate induction of PGC-1 and repression of PPAR-gamma by CREB during fasting provides a molecular rationale for the antagonism between insulin and counter-regulatory hormones, and indicates a potential role for CREB antagonists as therapeutic agents in enhancing insulin sensitivity in the liver.

  8. Expected Sensitivity of the Nuclear Compton Telescope to Gamma-Ray Line Emission

    NASA Astrophysics Data System (ADS)

    Chiu, Jeng-Lun; Bandstra, M. E.; Boggs, S. E.; NCT Collaboration

    2008-03-01

    The Nuclear Compton Telescope (NCT) is a balloon-borne soft gamma-ray (0.2-10 MeV) telescope designed to study astrophysical sources of nuclear line emission and gamma-ray polarization. NCT consists of twelve 3D position-sensitive germanium strip detectors. The ultra-compact design and new technologies allow NCT to achieve high efficiency with excellent spectral resolution and background reduction. We are currently preparing for a conventional balloon flight ( 36 hr) of the NCT instrument from New Mexico in September 2008 and a long-duration balloon flight (LDBF) ( 20 days) from Australia in December 2009. Here we focus on the LDBF in 2009. Our source and background simulations are performed using the Monte Carlo simulation package MGGPOD, and events are reconstructed using the Medium Energy Gamma-ray Astronomy library (MEGAlib). We use the same tools that were successfully used for background simulations of the 2005 prototype flight (see J. Bowen, this conference). Sensitivity is optimized using standard cuts such as photon energy, angular resolution measure (ARM), and event quality factor. In this work, we present realistic line sensitivities for NCT for the LDBF in 2009.

  9. Particle-gamma and particle-particle correlations in nuclear reactions using Monte Carlo Hauser-Feshback model

    SciTech Connect

    Kawano, Toshihiko; Talou, Patrick; Watanabe, Takehito; Chadwick, Mark

    2010-01-01

    Monte Carlo simulations for particle and {gamma}-ray emissions from an excited nucleus based on the Hauser-Feshbach statistical theory are performed to obtain correlated information between emitted particles and {gamma}-rays. We calculate neutron induced reactions on {sup 51}V to demonstrate unique advantages of the Monte Carlo method. which are the correlated {gamma}-rays in the neutron radiative capture reaction, the neutron and {gamma}-ray correlation, and the particle-particle correlations at higher energies. It is shown that properties in nuclear reactions that are difficult to study with a deterministic method can be obtained with the Monte Carlo simulations.

  10. Nuclear Magnetic Resonance (NMR) Spectroscopic Characterization of Nanomaterials and Biopolymers

    NASA Astrophysics Data System (ADS)

    Guo, Chengchen

    Nanomaterials have attracted considerable attention in recent research due to their wide applications in various fields such as material science, physical science, electrical engineering, and biomedical engineering. Researchers have developed many methods for synthesizing different types of nanostructures and have further applied them in various applications. However, in many cases, a molecular level understanding of nanoparticles and their associated surface chemistry is lacking investigation. Understanding the surface chemistry of nanomaterials is of great significance for obtaining a better understanding of the properties and functions of the nanomaterials. Nuclear magnetic resonance (NMR) spectroscopy can provide a familiar means of looking at the molecular structure of molecules bound to surfaces of nanomaterials as well as a method to determine the size of nanoparticles in solution. Here, a combination of NMR spectroscopic techniques including one- and two-dimensional NMR spectroscopies was used to investigate the surface chemistry and physical properties of some common nanomaterials, including for example, thiol-protected gold nanostructures and biomolecule-capped silica nanoparticles. Silk is a natural protein fiber that features unique properties such as excellent mechanical properties, biocompatibility, and non-linear optical properties. These appealing physical properties originate from the silk structure, and therefore, the structural analysis of silk is of great importance for revealing the mystery of these impressive properties and developing novel silk-based biomaterials as well. Here, solid-state NMR spectroscopy was used to elucidate the secondary structure of silk proteins in N. clavipes spider dragline silk and B. mori silkworm silk. It is found that the Gly-Gly-X (X=Leu, Tyr, Gln) motif in spider dragline silk is not in a beta-sheet or alpha-helix structure and is very likely to be present in a disordered structure with evidence for 31-helix

  11. Nuclear Magnetic Resonance Study of High Temperature Superconductivity

    NASA Astrophysics Data System (ADS)

    Mounce, Andrew M.

    The high temperature superconductors HgBa2CuO 4+delta (Hg1201) and Bi2SrCa2Cu2O 8+delta (Bi2212) have been treated with 17O for both nuclear magnetic resonance (NMR) sensitivity and various electronic properties. Subsequently, NMR experiments were performed on Hg1201 and Bi2212 to reveal the nature of the pseudogap, in the normal state, and vortex phases, in the superconducting state. NMR has been performed on 17O in an underdoped Hg1201 crystal with a superconducting transition transition temperature of 74 K to look for circulating orbital currents proposed theoretically and inferred from neutron scattering. The measurements reveal narrow spectra which preclude static local fields in the pseudogap phase at the apical site, suggesting that the moments observed with neutrons are fluctuating or the orbital current ordering is not the correct model for the neutron scattering observation. The fine detail of the NMR frequency shifts at the apical oxygen site are consistent with a dipolar field from the Cu+2 site and diamagnetism below the superconducting transition. It has been predicted that superconducting vortices should be electrically charged and that this effect is particularly enhanced for high temperature superconductors. Here it is shown that the Abrikosov vortex lattice, characteristic of the mixed state of superconductors, will become unstable at sufficiently high magnetic field if there is charge trapped on the vortex core for highly anisotropic superconductors. NMR measurements of the magnetic fields generated by vortices in Bi2212 single crystals provide evidence for an electro-statically driven vortex lattice reconstruction with the magnitude of charge on each vortex pancake of 2x10-3e, depending on doping, in line with theoretical estimates. Competition with magnetism is at the heart of high temperature superconductivity, most intensely felt near a vortex core. To investigate vortex magnetism spatially resolved NMR has been used, finding a strongly non

  12. Microstructure of Wet Cement Pastes: a Nuclear Magnetic Resonance Study

    NASA Astrophysics Data System (ADS)

    Jehng, Jyh-Yuar

    1995-01-01

    Nuclear magnetic resonance relaxation analysis has been applied to interpret the evolution of microstructure in a cement paste during hydration. The work in this thesis has yielded a better understanding of the geometric and physical characterization of porous materials, and specifically cement pastes. A basic understanding of the wet-dry and freeze-thaw processes of cement pastes has been developed. The pore structure evolution has been studied by the suppression of the freezing temperature of water and compared with relaxation analysis performed at room temperature. Both methods consistently show that hydrating cement pastes have two principal components in their size distribution. Firstly, in situ measurements have been made of the water consumption, the total specific surface area, and pore water size distribution as a function of hydration time. The amount of evaporable water in the pore space can be determined from the magnitude of the NMR signal, and the NMR relaxation times provide a measure of the characteristic pore sizes. Drying studies have been performed to determine the surface spin-spin relaxation time. The NMR results on evolution of cement pore structure with hydration clearly show five different stages. The water consumption was determined to be a linear function of the logarithm of hydration time over a wide range during which the total surface area of the wet gel remains constant. These experiments support a model of capillary and gel pores in the cement paste and provide strong evidence of a stable dense-gel structure. Secondly, supercooling and thawing point depression of confined water has been studied systematically. The depression of the freezing point of liquid water confined within a pore was found to be dependent on the pore size with capillary pore water freezing at 240 K and the remaining gel pore water freezing over a temperature range extending to as low as 160 K. Finally, an important application of NMR has been developed to monitor

  13. Fast Fourier Transform Chlorine Nuclear Quadrupole Resonance Spectroscopy.

    NASA Astrophysics Data System (ADS)

    D'Iorio, Marie

    A nuclear quadrupole resonance spectrometer operating in the frequency range 1-40 MHz was updated for fast Fourier transform spectroscopy and coupled to a Nicolet 1180 computer and data acquisition system. It was used with a low temperature cryostat for studies shown down to liquid helium temperature and with a high pressure/low temperature system for studies down to liquid nitrogen temperature and up to six kilobars. The study of the ('35)Cl NQR spectrum of K(,2)OsCl(,6) at 298 K and 77 K revealed the presence of a satellite associated with the nearest neighbour chlorines to H('+) ion impurities located at vacant octahedral sties. This result is in agreement with the predictions of a point charge model calculation. A residence time for the H('+) ion was deduced and is consistent with the result obtained from dielectric measurements. A detailed study of the ('35)Cl NQR frequency in K(,2)ReCl(,6) was performed in the temperature range 85 - 130K where two structural phase transitions occur, and at pressures from 1 to 2643 bars. A number of unusual features were revealed and discussed as the possible signature of incommensurate behavior. The primary effect of the pressure was to alter the temperatures at which the phase transitions occurred. Contrary to the behavior expected, the transition temperature for the antiferrorotative transition has a negative pressure coefficient. The spin-lattice and spin-spin relaxation times for the ('35)Cl and ('37)Cl isotopes of the one dimensional XY system, PrCl(,3), were measured at 4.2K. The spin-lattice relaxation is exponential and dominated by magnetic dipole -dipole interactions. The spin-spin relaxation is non-exponential and dominated by electric quadrupolar interactions arising from the coupling of the electric dipole moment at the praseodymium site and the quadrupole moment of the chlorine ion. The temperature dependence of the spin-spin relaxation time was investigated. At 17.4 K both magnetic dipolar and electric

  14. Novel detection schemes of nuclear magnetic resonance and magnetic resonance imaging: applications from analytical chemistry to molecular sensors.

    PubMed

    Harel, Elad; Schröder, Leif; Xu, Shoujun

    2008-01-01

    Nuclear magnetic resonance (NMR) is a well-established analytical technique in chemistry. The ability to precisely control the nuclear spin interactions that give rise to the NMR phenomenon has led to revolutionary advances in fields as diverse as protein structure determination and medical diagnosis. Here, we discuss methods for increasing the sensitivity of magnetic resonance experiments, moving away from the paradigm of traditional NMR by separating the encoding and detection steps of the experiment. This added flexibility allows for diverse applications ranging from lab-on-a-chip flow imaging and biological sensors to optical detection of magnetic resonance imaging at low magnetic fields. We aim to compare and discuss various approaches for a host of problems in material science, biology, and physics that differ from the high-field methods routinely used in analytical chemistry and medical imaging.

  15. Plasma processing of spent nuclear fuel by two-frequency ion cyclotron resonance heating

    SciTech Connect

    Timofeev, A. V.

    2009-11-15

    A previously developed method for analyzing the plasma processing of spent nuclear fuel is generalized to a plasma containing multicharged fuel ions. In such a plasma, ion cyclotron resonance heating of nuclear ash ions should be carried out in two monochromatic RF fields of different frequencies, provided that the fraction of {xi} multicharged ions is small, {xi} {<=} 0.1, a condition that substantially restricts the productivity of systems for processing spent nuclear fuel. Ways of overcoming this difficulty are discussed.

  16. Nuclear receptor ERR alpha and coactivator PGC-1 beta are effectors of IFN-gamma-induced host defense.

    PubMed

    Sonoda, Junichiro; Laganière, Josée; Mehl, Isaac R; Barish, Grant D; Chong, Ling-Wa; Li, Xiangli; Scheffler, Immo E; Mock, Dennis C; Bataille, Alain R; Robert, Francois; Lee, Chih-Hao; Giguère, Vincent; Evans, Ronald M

    2007-08-01

    Macrophage activation by the proinflammatory cytokine interferon-gamma (IFN-gamma) is a critical component of the host innate response to bacterial pathogenesis. However, the precise nature of the IFN-gamma-induced activation pathway is not known. Here we show using genome-wide expression and chromatin-binding profiling that IFN-gamma induces the expression of many nuclear genes encoding mitochondrial respiratory chain machinery via activation of the nuclear receptor ERR alpha (estrogen-related receptor alpha, NR3B1). Studies with macrophages lacking ERR alpha demonstrate that it is required for induction of mitochondrial reactive oxygen species (ROS) production and efficient clearance of Listeria monocytogenes (LM) in response to IFN-gamma. As a result, mice lacking ERR alpha are susceptible to LM infection, a phenotype that is localized to bone marrow-derived cells. Furthermore, we found that IFN-gamma-induced activation of ERR alpha depends on coactivator PGC-1 beta (peroxisome proliferator-activated receptor gamma coactivator-1 beta), which appears to be a direct target for the IFN-gamma/STAT-1 signaling cascade. Thus, ERR alpha and PGC-1 beta act together as a key effector of IFN-gamma-induced mitochondrial ROS production and host defense.

  17. Delayed Gamma-Ray Spectroscopy for Non-Destructive Assay of Nuclear Materials

    SciTech Connect

    Ludewigt, Bernhard; Mozin, Vladimir; Campbell, Luke; Favalli, Andrea; Alan W. Hunt; Edward T. Reedy; Heather A. Seipel

    2015-06-01

    Modeling capabilities were added to an existing framework and codes were adapted as needed for analyzing experiments and assessing application-specific assay concepts including simulation of measurements over many short irradiation/spectroscopy cycles. The code package was benchmarked against the data collected at the IAC for small targets and assembly-scale data collected at LANL. A study of delayed gamma-ray spectroscopy for nuclear safeguards was performed for a variety of assemblies in the extensive NGSI spent fuel library. The modeling results indicate that delayed gamma-ray responses can be collected from spent fuel assemblies with statistical quality sufficient for analyzing their isotopic composition using a 1011 n/s neutron generator and COTS detector instrumentation.

  18. Gamma-Ray Spectrometer based on a Transition Edge Sensor for Nuclear Materials Analysis

    NASA Astrophysics Data System (ADS)

    Hatakeyama, S.; Ohno, M.; Takahashi, H.; Damayanthi, R. M. T.; Otani, C.; Yasumune, T.; Ohnishi, T.; Takasaki, K.; Koyama, S.

    2014-08-01

    We designed and fabricated a hard X-ray and gamma-ray TES spectrometer for nuclear materials analysis. The superconducting tin absorber is coupled to an Ir/Au TES by using a gold post to improve the thermal contact between the absorber and the TES. The reported energy resolution is 156 eV FWHM at 59.5 keV and 166 eV FWHM at 122 keV gamma-rays. We performed measurement of a Pu sample and clearly separated the Pu (56.828 keV) and the Am (59.5 keV) peaks by this TES microcalorimeter which cannot be resolved by the HPGe detector.

  19. An airborne gamma-ray spectrometry survey of nuclear sites in Belgium.

    PubMed

    Sanderson, D C W; Cresswell, A J; Hardeman, F; Debauche, A

    2004-01-01

    As part of a wider study to define the existing background levels in Belgium an airborne gamma-ray survey was conducted in two areas associated with nuclear sites. In the Mol area, the survey zone included areas surrounding the SCK-CEN nuclear research centre, and its associated neighbourhood which includes radioactive waste stores, fuel manufacture and fabrication facilities and an international accelerator laboratory. In the vicinity of Fleurus, the survey included the IRE complex with radiochemical laboratories, irradiation facilities and stores, and isotope production accelerators. The survey was conducted using a twin engined helicopter equipped with a combined scintillation and semiconductor spectrometer. The system was installed and tested in the UK, and then transferred to Belgium for operations. The complete survey was conducted successfully within 1 week. The results provide a comprehensive record of the radiation environment of the nuclear sites at time of survey, and show a range of signals associated with the types of activity present in each area. They confirm that radiation fields are largely confined to the operational sites, and provide a traceable record against which future changes could be assessed. The demonstration of efficient deployment between two European countries, coupled with rapid mapping of many different radiometric signals around these sites confirms the utility of the airborne gamma spectrometry approach for accurate definition of enhanced radiation fields. This has important implications for emergency response.

  20. Applications of LaBr3(Ce) Gamma-ray Spectrometer Arrays for Nuclear Spectroscopy and Radionuclide Assay

    NASA Astrophysics Data System (ADS)

    Regan, PH; Shearman, R.; Daniel, T.; Lorusso, G.; Collins, SM; Judge, SM; Bell; Pearce, AK; Gurgi, LA; Rudigier, M.; Podolyák, Zs; Mărginean, N.; Mărginean, R.; Kisyov, S.

    2016-10-01

    An overview of the use of discrete energy gamma-ray detectors based on cerium- doped LaBr3 scintillators for use in nuclear spectroscopy is presented. This review includes recent applications of such detectors in mixed, 'hybrid' gamma-ray coincidence detection arrays such ROSPHERE at IFIN-HH, Bucharest; EXILL+FATIMA at ILL Grenoble, France; GAMMASPHERE+FATIMA at Argonne National Laboratory, USA; FATIMA + EURICA, at RIKEN, Japan; and the National Nuclear Array (NANA) at the UK's National Physical Laboratory. This conference paper highlights the capabilities and limitations of using these sub-nanosecond 'fast-timing', medium-resolution gamma-ray detectors for both nuclear structure research and radionuclide standardisation. Potential future application of such coincidence scintillator arrays in measurements of civilian nuclear fuel waste evaluation and assay is demonstrated using coincidence spectroscopy of a mixed 134,7Cs source.

  1. Nuclear magnetic resonance of laser-polarized noble gases in molecules, materials and organisms

    SciTech Connect

    Goodson, Boyd McLean

    1999-12-01

    Conventional nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI) are fundamentally challenged by the insensitivity that stems from the ordinarily low spin polarization achievable in even the strongest NMR magnets. However, by transferring angular momentum from laser light to electronic and nuclear spins, optical pumping methods can increase the nuclear spin polarization of noble gases by several orders of magnitude, thereby greatly enhancing their NMR sensitivity. This dissertation is primarily concerned with the principles and practice of optically pumped nuclear magnetic resonance (OPNMR). The enormous sensitivity enhancement afforded by optical pumping noble gases can be exploited to permit a variety of novel NMR experiments across many disciplines. Many such experiments are reviewed, including the void-space imaging of organisms and materials, NMR and MRI of living tissues, probing structure and dynamics of molecules in solution and on surfaces, and zero-field NMR and MRI.

  2. Nuclear Magnetic Resonance Nondestructive Evaluation of Composite Materials

    DTIC Science & Technology

    1990-04-09

    Pat. Appl. EP 26265, 8 Apr 1981, 13 pp. (1981). 9. A. N. Garroway , J. Baum, M. G. Munowitz, and A. Pines, NMR Imaging in Solids by Multiple-Quantum...Resonance, J. Magn. Reson. 60(2), 337-41 (1984). 10. J. Baum, A. N. Garroway , M. Munowitz, and A. Pines, Multiple-Quantum NMR in Solids: Application to... Garroway , NMR Images of Solids, J. Magn. Reson. 66(3), 530-5 (1986). 28. J. B. Miller and A. N. Garroway , Removal of Static Field Inhomogeneity and

  3. Delayed Gamma-Ray Spectroscopy for Non-Destructive Assay of Nuclear Materials

    SciTech Connect

    Ludewigt, Bernhard; Mozin, Vladimir; Campbell, Luke; Favalli, Andrea; Alan W. Hunt; Reedy, Edward T.E.; Seipel, Heather

    2015-06-01

    High-­energy, beta-delayed gamma-­ray spectroscopy is a potential, non-­destructive assay techniques for the independent verification of declared quantities of special nuclear materials at key stages of the fuel cycle and for directly assaying nuclear material inventories for spent fuel handling, interim storage, reprocessing facilities, repository sites, and final disposal. Other potential applications include determination of MOX fuel composition, characterization of nuclear waste packages, and challenges in homeland security and arms control verification. Experimental measurements were performed to evaluate fission fragment yields, to test methods for determining isotopic fractions, and to benchmark the modeling code package. Experimental measurement campaigns were carried out at the IAC using a photo-­neutron source and at OSU using a thermal neutron beam from the TRIGA reactor to characterize the emission of high-­energy delayed gamma rays from 235U, 239Pu, and 241Pu targets following neutron induced fission. Data were collected for pure and combined targets for several irradiation/spectroscopy cycle times ranging from 10/10 seconds to 15/30 minutes.The delayed gamma-ray signature of 241Pu, a significant fissile constituent in spent fuel, was measured and compared to 239Pu. The 241Pu/239Pu ratios varied between 0.5 and 1.2 for ten prominent lines in the 2700-­3600 keV energy range. Such significant differences in relative peak intensities make it possible to determine relative fractions of these isotopes in a mixed sample. A method for determining fission product yields by fitting the energy and time dependence of the delayed gamma-­ray emission was developed and demonstrated on a limited 235U data set. De-­convolution methods for determining fissile fractions were developed and tested on the experimental data. The use of high count-­rate LaBr3 detectors

  4. Gamma-resonance study of the reaction of iron ions with synthetic L-dopa melanin

    SciTech Connect

    Bagirov, R.M.; Stukan, R.A.; Lapina, V.A.; Dontsov, A.E.; Ostrovskii, M.A.

    1986-07-01

    The reaction of Fe/sup 3 +/ and Fe/sup 2 +/ ions with synthetic L-dopa melanin, which is a model compound of natural melanin (the melanoprotein granules in the pigment epithelial cells in vertebrate and human eyes), has been studied by gamma-resonance spectroscopy. The investigations showed that L-dopa melanin is capable of effectively binding iron ions and that it displays oxidative or reducing properties with respect to Fe, depending on the composition of the subsystem of the Fe ions and the ambient pH. Trivalent Fe/sup 3 +/ ions form stronger complexes with L-dopa melanin than do Fe/sup 2 +/ ions. The coordination takes place mainly with the carboxyl groups and the amino and imino groups of the polymer. The conformational state of the polymer apparently changes as the pH is varied.

  5. Adiabatic Non-resonant Acceleration in Magnetic Turbulence and Hard Spectra of Gamma-Ray Bursts

    NASA Astrophysics Data System (ADS)

    Xu, Siyao; Zhang, Bing

    2017-09-01

    We introduce a non-resonant acceleration mechanism arising from the second adiabatic invariant in magnetic turbulence and apply it to study the prompt emission spectra of gamma-ray bursts (GRBs). The mechanism contains both the first- and second-order Fermi acceleration, originating from the interacting turbulent reconnection and dynamo processes. It leads to a hard electron energy distribution up to a cutoff energy at the balance between the acceleration and synchrotron cooling. The sufficient acceleration rate ensures a rapid hardening of any initial energy distribution to a power-law distribution with the index p∼ 1, which naturally produces a low-energy photon index α ∼ -1 via the synchrotron radiation. For typical GRB parameters, the synchrotron emission can extend to a characteristic photon energy on the order of ∼100 keV.

  6. Resonant Compton cooling and annihilation line production in gamma-ray bursts

    NASA Technical Reports Server (NTRS)

    Preece, R. D.; Harding, A. K.

    1992-01-01

    Attention is given to a synchrotron self-Compton emission model for gamma-ray bursts which produces narrow annihilation features for a variety of field strengths, primary electron injection energies, and injection rates. In this model, primary electrons are injected and cooled by synchrotron emission in a strong, homogeneous magnetic field, resulting in a pair cascade. Multiple resonant scattering with cyclotron photons efficiently traps and cools pairs in the ground state to an average energy where the Compton energy loss rate is zero, which is in agreement with previous estimates of a Compton temperature. The particle distributions in the ground state are determined by numerically solving the Fokker-Planck equation in the steady state. In the case of isotropic injection of primary electrons, a significant narrow-line feature appears in the overall emission. In the case of beamed injection, the annihilation line is broadened to the extent that it would not be observable.

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

    NASA Astrophysics Data System (ADS)

    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

  8. Studies of Energy-Relevant Materials by Nuclear Magnetic Resonance

    NASA Astrophysics Data System (ADS)

    Cui, Jinfang

    In this thesis, we have used nuclear magnetic resonance (NMR) as a local probe to microscopically study three different families of energy-relevant complex materials, namely the 122 Fe-based superconductors Ca(Fe1-xCox)2As2, GeTe-based thermoelectric tellurides GeTe and detonation nanodiamond. In Chapter 3 and Chapter 4, we investigated the Co substitution effects on static and dynamic magnetic properties of the single-crystalline Ca(Fe 1-xCox)2As2 (x = 0, 0.023, 0.028, 0.033, 0.059) via 75As NMR and resistivity measurements. Robustness of the Fe magnetic moments was evidenced by only slight decreases of Hint, although T N is strongly suppressed with Co substitution in antiferromagnetic (AFM) state. In the paramagnetic (PM) state, the temperature dependence of Knight shift K for all crystals shows similar T-dependence of magnetic susceptibility chi. The spin fluctuations with the q = 0 components are suppressed with Delta/k B. On the other hand, the growth of the stripe-type AFM fluctuations with q = (pi, 0) or (0, pi) upon cooling in the PM state for all samples is evidenced by the T-dependence of (1/ T1Tchi). A pseudogap-like phenomenon, i.e., suppression of the AFM spin fluctuations, was discovered with decreasing temperature below a x-independent characteristic temperature T* ( 100 K) in samples with x ≥ 0.028. In addition, clear evidence for the coexistence and competition of the stripe-type antiferromagnetic and ferromagnetic (FM) spin correlations was given by modified Korringa ratio analysis in Chapter 4. In Chapter 5, we have carried out 125Te NMR measurements to study the electronic properties of Ge50Te50, Ag 2Ge48Te50 and Sb2Ge48Te 50. NMR shift K and 1/T1T of Ge50Te50 are nearly temperature independent at T < 50 K and both increase slightly with increasing temperature at high temperatures. A two-band model, where one band overlaps the Fermi level and the other band is separated from the Fermi level by an energy gap, has been used to explain these

  9. An electron spin resonance study of gamma-ray irradiated ginseng.

    PubMed

    Nakamura, Hideo; Ukai, Mitsuko; Shimoyama, Yuhei

    2006-03-13

    Using electron spin resonance (ESR) spectroscopy, we revealed the presence of four radical species in gamma-ray irradiated ginseng (Agaliaceae). Before irradiation, the representative ESR spectrum of ginseng is composed of a sextet centered at g = 2.0, a sharp singlet at the same g-value, and a singlet at about g = 4.0. The first one is attributable to a hyperfine (hf) signal of Mn2+ ion (hf constant: 7.4 mT). The second one is due to an organic free radical. The third one is originated from Fe3+. Upon gamma-ray irradiation, a new ESR (the fourth) signal was detectable in the vicinity of g = 2.0 region. The progressive saturation behaviors of the ESR signals at various microwave power levels were indicative of different relaxation time for those radicals. The anisotropic ESR spectra were detected by the angular rotation of the sample tube. This is due to the existence of anisotropic microcrystalline in the ginseng powder sample.

  10. Cyclotron resonant scattering in the spectra of gamma-ray bursts

    NASA Technical Reports Server (NTRS)

    Wang, J. C. L.; Lamb, D. Q.; Loredo, T. J.; Wasserman, I. M.; Salpeter, E. E.

    1989-01-01

    Fits of theoretical spectra from Monte Carlo radiation-transfer calculations to dips at approximately 20 and 40 keV in a spectrum of the gamma-ray burst source GB 880 205 give best-fit values and 68 percent-confidence intervals for the magnetic field of (1.71 + or - 0.07) x 10 to the 12th G, the electron density of (1.2 + or - 0.6) x 10 to the 21st electrons/cm-squared, and the cosine of the viewing angle relative to the field of 0.31 + or - 0.05. The dips observed at approximately 20 keV in the spectra are interpreted as cyclotron resonant scattering, in which electrons undergo radiative 0 to 1 to 0 Landau transitions initiated by photons near the first harmonic. Physical self-consistency fixes the temperature, and the equilibrium temperature equals 5.3 + 0.3 or - 0.2 keV. These results suggest that this gamma-ray burst and many others which exhibit a low-energy dip originate from strongly magnetic neutron stars and are galactic in origin.

  11. Nuclear structure and shapes from prompt gamma ray spectroscopy of fission products

    SciTech Connect

    Ahmad, I.; Morss, L.R.; Durell, J.L.

    1996-10-01

    Many nuclear shape phenomena are predicted to occur in neutron-rich nuclei. The best source for the production of these nuclides is the spontaneous fission which produces practically hundreds of nuclides with yields of greater than 0.1 % per decay. Measurements of coincident gamma rays with large Ge arrays have recently been made to obtain information on nuclear structures and shapes of these neutron- rich nuclei. Among the important results that have been obtained from such measurements are octupole correlations in Ba isotopes, triaxial shapes in Ru nuclei, two-phonon vibrations in {sup 106}Mo and level lifetimes and quadrupole moments in Nd isotopes and A=100 nuclei. These data have been used to test theoretical models.

  12. Nuclear Molecular Resonances in Heavy-Ion Collisions.

    ERIC Educational Resources Information Center

    Erb, Karl A.; Bromley, D. Allan

    1979-01-01

    Explains that some nuclear scattering phenomena can be attributed to states in which two nuclei are bound to each other at their surfaces, revolving and vibrating for a time before coalescing or disintegrating. (Author/GA)

  13. Characterization of calcium-binding sites in the kidney stone inhibitor glycoprotein nephrocalcin with vanadyl ions: electron paramagnetic resonance and electron nuclear double resonance spectroscopy.

    PubMed Central

    Mustafi, D; Nakagawa, Y

    1994-01-01

    Nephrocalcin (NC) is a calcium-binding glycoprotein of 14,000 molecular weight. It inhibits the growth of calcium oxalate monohydrate crystals in renal tubules. The NC used in this study was isolated from bovine kidney tissue and purified with the use of DEAE-cellulose chromatography into four isoforms, designated as fractions A-D. They differ primarily according to the content of phosphate and gamma-carboxy-glutamic acid. Fractions A and B are strong inhibitors of the growth of calcium oxalate monohydrate crystal, whereas fractions C and D inhibit crystal growth weakly. Fraction A, with the highest Ca(2+)-binding affinity, was characterized with respect to its metal-binding sites by using the vanadyl ion (VO2+) as a paramagnetic probe in electron paramagnetic resonance (EPR) and electron nuclear double resonance (ENDOR) spectroscopic studies. By EPR spectrometric titration, it was shown that fraction A of NC bound VO2+ with a stoichiometry of metal:protein binding of 4:1. Also, the binding of VO2+ to NC was shown to be competitive with Ca2+. Only protein residues were detected by proton ENDOR as ligands, and these ligands bound with complete exclusion of solvent from the inner coordination sphere of the metal ion. This type of metal-binding environment, as derived from VO(2+)-reconstituted NC, differs significantly from the binding sites in other Ca(2+)-binding proteins. PMID:7972057

  14. Nuclear magnetic resonance studies of the blue copper protein plastocyanin

    SciTech Connect

    Kojiro, C.L.

    1985-01-01

    Plastocyanins (pcy) from a higher plant (spinach, Spinacia oleracea), a cyanobacterium (Anabaena variabilis), and a green alga (Chlorella fusca), were studied by /sup 1/H and /sup 13/C NMR. All three histidine /sup 13/C/sub ..gamma../ peaks in A. variabilis pcy were assigned. Previous assignments of the homologous /sup 13/C/sub ..gamma../ peaks in spinach pcy were corrected. A glutamic acid /sup 13/C/sub delta/ peak was found to titrate with an unusually high pK/sub a/ (approx.5.3); this peak was assigned to the N-terminal Glu-(-2). Exchange of /sup 113/Cd(II) for Cu(I) led to changes in chemical shifts of groups at the metal binding site. Spectral changes observed with residues as far as 18 A from the metal site indicate that the structure at the metal binding site is coupled to the structure at the opposite end of the molecule.

  15. Characterization of oleic acid and propranolol oleate mesomorphism using (13)C solid-state nuclear magnetic resonance spectroscopy (SSNMR).

    PubMed

    Crowley, K J; Forbes, R T; York, P; Apperley, D C; Nyqvist, H; Camber, O

    2000-10-01

    Lipids regularly exhibit complicated thermotropic and lyotropic phase behavior. In this study, the utility of (13)C solid-state nuclear magnetic resonance spectroscopy (SSNMR) in characterizing the phase properties of pharmaceutical lipids was investigated. Variable temperature (13)C SSNMR spectra and spin-lattice relaxation times (T(1)(C)) were obtained for high-purity oleic acid (OA) and propranolol oleate (POA). Spectral changes took place following OA gamma-to-alpha phase transition that indicated increased nuclear inequivalence of aliphatic chain carbons in the alpha phase. T(1)(C) data for the alpha phase demonstrated considerable conformational changes throughout the aliphatic chain, not solely in the methyl side chain as previously reported. These data support alpha-OA classification as a conformationally disordered crystalline phase. The prevalence of low T(1)(C) values in both POA I and II suggested the absence of a rigid crystalline molecular lattice, so both phases were described as conformationally disordered crystalline phases. A two-phase mixture of POA I and II was also identified, emphasizing the sensitivity of this technique. (13)C SSNMR provided valuable information regarding the nuclear environment of specific functional groups in lipid crystalline and mesomorphic structures. Understanding phase behavior at the molecular level can aid selection of appropriate formulation strategies for lipids by allowing prediction of processing properties, and physical and chemical stability. (13)C SSNMR is a powerful technique for pharmaceutical lipid characterization. Copyright 2000 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 89:1286-1295, 2000

  16. Radioisotope identification method for poorly resolved gamma-ray spectrum of nuclear security concern

    NASA Astrophysics Data System (ADS)

    Ninh, Giang Nguyen; Phongphaeth, Pengvanich; Nares, Chankow; Hao, Quang Nguyen

    2016-01-01

    Gamma-ray signal can be used as a fingerprint for radioisotope identification. In the context of radioactive and nuclear materials security at the border control point, the detection task can present a significant challenge due to various constraints such as the limited measurement time, the shielding conditions, and the noise interference. This study proposes a novel method to identify the signal of one or several radioisotopes from a poorly resolved gamma-ray spectrum. In this method, the noise component in the raw spectrum is reduced by the wavelet decomposition approach, and the removal of the continuum background is performed using the baseline determination algorithm. Finally, the identification of radioisotope is completed using the matrix linear regression method. The proposed method has been verified by experiments using the poorly resolved gamma-ray signals from various scenarios including single source, mixing of natural uranium with five of the most common industrial radioactive sources (57Co, 60Co, 133Ba, 137Cs, and 241Am). The preliminary results show that the proposed algorithm is comparable with the commercial method.

  17. Cosmic veto gamma-spectrometry for Comprehensive Nuclear-Test-Ban Treaty samples

    NASA Astrophysics Data System (ADS)

    Burnett, J. L.; Davies, A. V.

    2014-05-01

    The Comprehensive Nuclear-Test-Ban Treaty (CTBT) is supported by a global network of monitoring stations that perform high-resolution gamma-spectrometry on air filter samples for the identification of 85 radionuclides. At the UK CTBT Radionuclide Laboratory (GBL15), a novel cosmic veto gamma-spectrometer has been developed to improve the sensitivity of station measurements, providing a mean background reduction of 80.8% with mean MDA improvements of 45.6%. The CTBT laboratory requirement for a 140Ba MDA is achievable after 1.5 days counting compared to 5-7 days using conventional systems. The system consists of plastic scintillation plates that detect coincident cosmic-ray interactions within an HPGe gamma-spectrometer using the Canberra LynxTM multi-channel analyser. The detector is remotely configurable using a TCP/IP interface and requires no dedicated coincidence electronics. It would be especially useful in preventing false-positives at remote station locations (e.g. Halley, Antarctica) where sample transfer to certified laboratories is logistically difficult. The improved sensitivity has been demonstrated for a CTBT air filter sample collected after the Fukushima incident.

  18. Photo-nuclear astrophysics in NewSUBARU {gamma}-ray source

    SciTech Connect

    Hayakawa, Takehito

    2010-08-12

    A laser Compton scattering (LCS){gamma}-ray source has been installed at an electron storage ring NewSUBARU at SPring-8. We have studied the nuclear physics using this LCS g-ray source. The half-lives of unstable isotopes, {sup 184}Re and {sup 164}Ho{sup m}, produced by photo-induced reactions have been measured. These half-lives are shorter than previous recommended values by 7% and 3%, respectively. These changes of the half-lives affects to evaluation of cross-sections using the activation method. We have discussed a problem of the residual ratio of an isomer in {sup 180}Ta in supernova explosions. The unstable ground state and the metastable isomer are linked by ({gamma}, {gamma}') reactions. We have developed a new time-dependent model to calculate the isomer ratio in supernovae. The solar abundance of {sup 180}Ta is reproduced by the supernova neutrino process with the present calculated isomer ratio.

  19. Radioisotope identification method for poorly resolved gamma-ray spectrum of nuclear security concern

    SciTech Connect

    Ninh, Giang Nguyen; Phongphaeth, Pengvanich Nares, Chankow; Hao, Quang Nguyen

    2016-01-22

    Gamma-ray signal can be used as a fingerprint for radioisotope identification. In the context of radioactive and nuclear materials security at the border control point, the detection task can present a significant challenge due to various constraints such as the limited measurement time, the shielding conditions, and the noise interference. This study proposes a novel method to identify the signal of one or several radioisotopes from a poorly resolved gamma-ray spectrum. In this method, the noise component in the raw spectrum is reduced by the wavelet decomposition approach, and the removal of the continuum background is performed using the baseline determination algorithm. Finally, the identification of radioisotope is completed using the matrix linear regression method. The proposed method has been verified by experiments using the poorly resolved gamma-ray signals from various scenarios including single source, mixing of natural uranium with five of the most common industrial radioactive sources (57Co, 60Co, 133Ba, 137Cs, and 241Am). The preliminary results show that the proposed algorithm is comparable with the commercial method.

  20. Evaluation of intersubchannel mixing in a simulated nuclear fuel rod bundle using a gamma camera

    SciTech Connect

    Sedaghat-Hamedani, A.

    1984-01-01

    Single-phase, isothermal turbulent and forced mixing data were obtained from two and three-subchannel simulations of a nuclear fuel assembly using a gamma-camera imaging system. One of the two or three inlet streams was traced with the gamma emitting radionuclide 99m-Tc pertechnetate, and axial subchannel concentration gradients were measured as a function of gap spacing and Reynolds number over the respective ranges 0.050 to 0.197 inch, and 3000 to 20,000. The gamma camera allowed external monitoring over the axial length of the test assembly thereby eliminating experimental problems associated with flow partitioning and withdrawal systems. In addition, it provided a methodology for making noninvasive measurements under operating conditions downstream of a mixing vane and over the active region of diversion crossflow. The missing parameter ..beta.., defined as the ratio of the transverse to axial mass velocities, was found to be relatively independent of the pitch to rod diameter ratio for gap spaces of 0.100, 0.157, and 0.197 inches, but was observed to increase sharply for the smallest gap spacing (0.050 inch) at a constant Reynolds number. Diversion crossflow was characterized by providing fixed but different flow rate to each subchannel.

  1. Development of the new gamma-ray calorimeter for the measurement of Pigmy Dipole Resonance

    NASA Astrophysics Data System (ADS)

    Shikata, Mizuki; Nakamura, Takashi; Togano, Yasuhiro; Kondo, Yosuke

    2014-09-01

    A new γ-ray calorimeter CATANA (CAlorimeter for gamma γ-ray Transition in Atomic Nuclei at high isospin Asynmetry) has been developed to measure highly excited states like the pygmy dipole resonance and the giant dipole resonance. CATANA will be used with the SAMURAI spectrometer at RIBF. The excitation energy spectrum will be reconstructed combining the invariant mass of the reaction products measured by SAMURAI and γ-ray energies from CATANA. CATANA has focused on achieving a high detection efficiency. It is calculated as 56% for 1 MeV γ-rays from beam with a velocity of β = 0.6. The CATANA array consists of 200 CsI(Na) crystals and covers angles from 10 to 120 degrees along the beam axis. In this study, we have tested prototype crystals of CATANA to evaluate their performance. A position dependence of the light input have been measured and compared with a Monte-Carlo simulation based on GEANT4. In this talk, we will report the design of CATANA and the result of the tests and the simulation.

  2. Neutron activation analysis via nuclear decay kinetics using gamma-ray spectroscopy at SFU

    NASA Astrophysics Data System (ADS)

    Domingo, Thomas; Chester, Aaron; Starosta, Krzysztof; Williams, Jonathan

    2016-09-01

    Gamma-ray spectroscopy is a powerful tool used in a variety of fields including nuclear and analytical chemistry, environmental science, and health risk management. At SFU, the Germanium detector for Elemental Analysis and Radiation Studies (GEARS), a low-background shielded high-purity germanium gamma-ray detector, has been used recently in all of the above fields. The current project aims to expand upon the number of applications for which GEARS can be used while enhancing its current functionality. A recent addition to the SFU Nuclear Science laboratory is the Thermo Scientific P 385 neutron generator. This device provides a nominal yield of 3 ×108 neutrons/s providing the capacity for neutron activation analysis, opening a major avenue of research at SFU which was previously unavailable. The isotopes created via neutron activation have a wide range of half-lives. To measure and study isotopes with half-lives above a second, a new analogue data acquisition system has been installed on GEARS allowing accurate measurements of decay kinetics. This new functionality enables identification and quantification of the products of neutron activation. Results from the neutron activation analysis of pure metals will be presented.

  3. Gamma ray beams for Nuclear Astrophysics: first results of tests and simulations of the ELISSA array

    NASA Astrophysics Data System (ADS)

    La Cognata, M.; Anzalone, A.; Balabanski, D.; Chesnevskaya, S.; Crucillà, V.; Filipescu, D. M.; Guardo, G. L.; Gulino, M.; Lattuada, D.; Matei, C.; Pizzone, R. G.; Romano, S.; Spitaleri, C.; Taffara, A.; Tesileanu, O.; Tumino, A.; Xu, Y.

    2017-03-01

    The Extreme Light Infrastructure-Nuclear Physics (ELI-NP) facility, under construction in Magurele near Bucharest in Romania, will provide high-intensity and high-resolution gamma ray beams that can be used to address hotly debated problems in nuclear astrophysics. For this purpose, a silicon strip detector array (named ELISSA) will be realized in a common effort by ELI-NP and INFN-LNS (Catania, Italy), in order to measure excitation functions and angular distributions over a wide energy and angular range. A prototype of ELISSA was built and tested at Laboratori Nazionali del Sud (INFN-LNS) in Catania with the support of ELI-NP. On this occasion, we carried out experiments with alpha sources and with a 11 MeV 7Li beam. Thanks to our approach, the first results of those tests show up a very good energy resolution (better than 1%) and very good position resolution, of the order of 1 mm. Below 1 MeV, a resolution of the order of 6 mm is found, still good enough for the measurement of angular distribution and the kinematical identification of the reactions induced on the target by gamma beams.

  4. Discovery of Cyclotron Resonance Features in the Soft Gamma Repeater SGR 1806-20

    NASA Technical Reports Server (NTRS)

    Ibrahim, Alaa I.; Safi-Harb, Samar; Swank, Jean H.; Parke, William; Zane, Silvia; Turolla, Roberto

    2002-01-01

    We report evidence of cyclotron resonance features from the Soft Gamma Repeater SGR 1806-20 in outburst, detected with the Rossi X-ray Timing Explorer in the spectrum of a long, complex precursor that preceded a strong burst. The features consist of a narrow 5.0 keV absorption line with modulation near its second and third harmonics (at 11.2 keV and 17.5 keV respectively). The line features are transient and are detected in the harder part of the precursor. The 5.0 keV feature is strong, with an equivalent width of approx. 500 eV and a narrow width of less than 0.4 keV. Interpreting the features as electron cyclotron lines in the context of accretion models leads to a large mass-radius ratio (M/R greater than 0.3 solar mass/km) that is inconsistent with neutron stars or that requires a low (5-7) x 10(exp 11) G magnetic field that is unlikely for SGRs. The line widths are also narrow compared with those of electron cyclotron resonances observed so far in X-ray pulsars. In the magnetar picture, the features are plausibly explained as ion cyclotron resonances in an ultra-strong magnetic field that have recently been predicted from magnetar candidates. In this view, the 5.0 keV feature is consistent with a proton cyclotron fundamental whose energy and width are close to model predictions. The line energy would correspond to a surface magnetic field of 1.0 x 10(exp 15) G for SGR 1806-20, in good agreement with that inferred from the spin-down measure in the source.

  5. Discovery of Cyclotron Resonance Features in the Soft Gamma Repeater SGR 1806-20

    NASA Technical Reports Server (NTRS)

    Ibrahim, A. I.; Safi-Harb, Samar; Swank, Jean H.; Parke, William; Zane, Silvia; Turolla, Roberto; White, Nicholas E. (Technical Monitor)

    2002-01-01

    We report evidence for cyclotron resonance features from the Soft Gamma Repeater SCR 1806-20 in outburst, detected with the Rossi X-ray Timing Explorer in the spectrum of a long, complex precursor that preceded a strong burst. The features consist of a narrow 5.0 keV absorption line with modulation near its second and third harmonics (at 11.2 keV and 17.5 keV respectively). The line features are transient and are detected in the harder part of the precursor. The 5.0 keV feature is strong, with an equivalent width of approx. 500 eV, and a narrow width of < 0.4 keV. Interpreting the features as electron cyclotron lines in the context of accretion models leads to a large mass-radius ratio (M/R > 0.3 Solar Mass/km) that is inconsistent with neutron stars, or requires a low (5 - 7) x 10(exp 11) G magnetic field that is unlikely for SGRs. The line widths are also narrow compared to those of electron cyclotron resonances observed so far in X-ray pulsars. In the magnetar picture, the features are plausibly explained as ion cyclotron resonances in an ultra-strong magnetic field, which have recently been predicted from magnetar candidates. In this view, the 5.0 keV feature is consistent with a proton cyclotron fundamental whose energy and width are close to model predictions. The line energy would correspond to a surface magnetic field of 1.0 x 10(exp 15) G for SGR 1806-20, in good agreement with that inferred from the spin-down measure in the source.

  6. Nuclear resonance reflection of synchrotron radiation from thin dysprosium films with different types of magnetic ordering

    NASA Astrophysics Data System (ADS)

    Andreeva, M. A.; Antropov, N. O.; Baulin, R. A.; Kravtsov, E. A.; Ryabukhina, M. V.; Yakunina, E. M.; Ustinov, V. V.

    2016-12-01

    Epitaxial thin films of dysprosium have been successfully synthesized by the method of high-vacuum magnetron sputtering and their structure and magnetic properties have been investigated. The opportunity of the nuclear resonance scattering for the investigation of nanostructures containing 161Dy has been considered; the specific features of the spectra of nuclear resonance reflectivity from the films have been analyzed on the energy and time scales at different orientations of the magnetic hyperfine field. The simulation of the angular dependences of nuclear resonance reflectivity for the case of spiral ordering in periodic structures containing 161Dy has been carried out. It has been shown that these dependences make it possible to uniquely determine the period of magnetic ordering.

  7. Atmospheric transport of neutrons and gamma rays from a high-altitude nuclear detonation

    SciTech Connect

    Byrd, R.C.

    1995-07-01

    Although radiation outputs from nuclear detonations in free space are well established, few studies exist of effect of atmospheric transport on the resulting intensity, energy, and time signatures. This report presents calculations for generic sources at high altitudes, 20-50 km above the Earth`s surface, in an atmosphere whose density decreases almost exponentially with height. The sources are instantaneous time bursts with simple energy dependences: gamma rays use an evaporation spectrum; neutrons use either a Gaussian fusion or a Maxwell fission spectrum. The observation angles vary from vertical to 5{degrees} below the horizon, and detectors are placed in either geosynchronous or low Earth orbits (100 km). All calculations use the Monte Carlo N-Particle (MCNP) transport code in either its photon, neutron, or coupled neutron-photon modes, with the coupled mode being applied to the production of gamma rays by neutron inelastic scattering. The standard MCNP outputs are analyzed to extract the intensity, energy, and time dependences of the fluence as functions of either source altitude or observation angle. In general, the intensities drop rapidly below about 30-km source altitude or +5` slant angle. Above these limits, the gamma-ray signal loses substantial intensity but still contains most of the original source information. In contrast, neutron scattering produces little or no decrease in intensity, but it rapidly degrades much of the information about the original source spectrum. Finally, although there is abundant gamma-ray production from neutron inelastic scattering, the resulting signatures appear to provide little additional information.

  8. Modeling the Production of Beta-Delayed Gamma Rays for the Detection of Special Nuclear Materials

    SciTech Connect

    Hall, J M; Pruet, J A; Brown, D A; Descalle, M; Hedstrom, G W; Prussin, S G

    2005-02-14

    The objective of this LDRD project was to develop one or more models for the production of {beta}-delayed {gamma} rays following neutron-induced fission of a special nuclear material (SNM) and to define a standardized formatting scheme which will allow them to be incorporated into some of the modern, general-purpose Monte Carlo transport codes currently being used to simulate inspection techniques proposed for detecting fissionable material hidden in sea-going cargo containers. In this report, we will describe a Monte Carlo model for {beta}-delayed {gamma}-ray emission following the fission of SNM that can accommodate arbitrary time-dependent fission rates and photon collection histories. The model involves direct sampling of the independent fission yield distributions of the system, the branching ratios for decay of individual fission products and spectral distributions representing photon emission from each fission product and for each decay mode. While computationally intensive, it will be shown that this model can provide reasonably detailed estimates of the spectra that would be recorded by an arbitrary spectrometer and may prove quite useful in assessing the quality of evaluated data libraries and identifying gaps in the libraries. The accuracy of the model will be illustrated by comparing calculated and experimental spectra from the decay of short-lived fission products following the reactions {sup 235}U(n{sub th}, f) and {sup 239}Pu(n{sub th}, f). For general-purpose transport calculations, where a detailed consideration of the large number of individual {gamma}-ray transitions in a spectrum may not be necessary, it will be shown that a simple parameterization of the {gamma}-ray source function can be defined which provides high-quality average spectral distributions that should suffice for calculations describing photons being transported through thick attenuating media. Finally, a proposal for ENDF-compatible formats that describe each of the models and

  9. High-Energy Delayed Gamma Spectroscopy for Spent Nuclear Fuel Assay

    SciTech Connect

    Campbell, Luke W.; Smith, Leon E.; Misner, Alex C.; Ressler, Jennifer J.

    2009-10-07

    High-accuracy, direct, nondestructive measurement of fissile and fissionable isotopes in spent fuel, particularly the Pu isotopes, is a well-documented, but still unmet challenge in international safeguards. As nuclear fuel cycles propagate around the globe, the need for improved materials accountancy techniques for irradiated light-water reactor fuel will only increase (e.g. for shipper-receiver verification at interim or permanent storage, or at the head end of a reprocessing plant). This modeling study investigates the use of delayed gamma rays from fission-product nuclei to directly measure the relative concentrations of U-235, Pu-239, and Pu-241 in spent fuel assemblies. The method is based on the unique distribution of fission-product nuclei produced from fission in each of these fissile isotopes. Fission is stimulated in the assembly with a beam of interrogating neutrons and the measured distributions of the short-lived fission products from the unknown sample are then fit with a linear combination of the known fission-product yield curves from pure U-235, Pu-239, and Pu-241 to determine the original proportions of these fissile isotopes. Modeling approaches for the intense gamma-ray background promulgated by the long-lived fission-product inventory, and the high-energy gamma-ray signatures emitted by short-lived fission products from induced fission are described. Results for the simulated assay of simplified individual fuel elements ranging from fresh to 60 GWd/MTU burnup are used to demonstrate the utility of the modeling methods and provide preliminary viability data for the technique. A limited set of benchmarking measurements, and additional work needed to more realistically assess the potential of the High-Energy Delayed Gamma Spectroscopy (HEDGS) technique are described.

  10. High-Energy Delayed Gamma Spectroscopy for Spent Nuclear Fuel Assay

    SciTech Connect

    Campbell, Luke W.; Smith, Leon E.; Misner, Alex C.

    2011-02-01

    High-accuracy, direct, nondestructive measurement of fissile and fissionable isotopes in spent fuel, particularly the Pu isotopes, is a well-documented, but still unmet challenge in international safeguards. As nuclear fuel cycles propagate around the globe, the need for improved materials accountancy techniques for irradiated light-water reactor fuel will increase. This modeling study investigates the use of delayed gamma rays from fission-product nuclei to directly measure the relative concentrations of U-235, Pu-239, and Pu-241 in spent fuel assemblies. The method is based on the unique distribution of fission-product nuclei produced from fission in each of these fissile isotopes. Fission is stimulated in the assembly with a pulse-capable source of interrogating neutrons. The measured distributions of the short-lived fission products from the unknown sample are then fit with a linear combination of the known fission-product yield curves from pure U-235, Pu-239, and Pu-241 to determine the original proportions of these fissile isotopes. Modeling approaches for the intense gamma-ray background promulgated by the long-lived fission-product inventory and for the high-energy gamma-ray signatures emitted by short-lived fission products from induced fission are described. Benchmarking measurements are presented and compare favorably with the results of these models. Results for the simulated assay of simplified individual fuel elements ranging from fresh to 60 GWd/MTU burnup demonstrate the utility of the modeling methods for viability studies, although additional work is needed to more realistically assess the potential of High-Energy Delayed Gamma Spectroscopy (HEDGS).

  11. Laser Electron Gamma Source Facility biennial progress report, June 1992

    SciTech Connect

    Caracappa, A.; Kuczewski, A.; Kistner, O.C.; Lincoln, F. ); Hoblit, S. . Dept. of Physics); Whisnant, C.S. South Carolina Univ., Columbia, SC . Dept. of Physics)

    1992-01-01

    This report briefly discusses the Laser Electron Gamma Source facility and the following experiments conducted here: polarization in D(gamma, p)n and N-N tensor forces for energies less than 225 Mev; constraints on the nuclear tensor force from D(gamma, p)n for energies less than 315 Mev; the p(gamma, neutral pion) reaction and the E2 excitation of delta resonance; quasi-two- and three-body absorption in helium 3(gamma, N-N); and the delta-nucleon interaction in D(gamma,p-negative pion)p and D(gamma, p-n)neutral pions. (LSP).

  12. Laser Electron Gamma Source Facility biennial progress report, June 1992

    SciTech Connect

    Caracappa, A.; Kuczewski, A.; Kistner, O.C.; Lincoln, F.; Hoblit, S.; Whisnant, C.S. |

    1992-08-01

    This report briefly discusses the Laser Electron Gamma Source facility and the following experiments conducted here: polarization in D(gamma, p)n and N-N tensor forces for energies less than 225 Mev; constraints on the nuclear tensor force from D(gamma, p)n for energies less than 315 Mev; the p(gamma, neutral pion) reaction and the E2 excitation of delta resonance; quasi-two- and three-body absorption in helium 3(gamma, N-N); and the delta-nucleon interaction in D(gamma,p-negative pion)p and D(gamma, p-n)neutral pions. (LSP).

  13. Design and development of a novel nuclear magnetic resonance detection for the gas phase ions by magnetic resonance acceleration technique

    NASA Astrophysics Data System (ADS)

    Fuke, K.; Tona, M.; Fujihara, A.; Sakurai, M.; Ishikawa, H.

    2012-08-01

    Nuclear magnetic resonance (NMR) technique is a well-established powerful tool to study the physical and chemical properties of a wide range of materials. However, presently, NMR applications are essentially limited to materials in the condensed phase. Although magnetic resonance was originally demonstrated in gas phase molecular beam experiments, no application to gas phase molecular ions has yet been demonstrated. Here, we present a novel principle of NMR detection for gas phase ions based on a "magnetic resonance acceleration" technique and describe the design and construction of an apparatus which we are developing. We also present an experimental technique and some results on the formation and manipulation of cold ion packets in a strong magnetic field, which are the key innovations to detect NMR signal using the present method. We expect this novel method to lead new realm for the study of mass-selected gas-phase ions with interesting applications in both fundamental and applied sciences.

  14. Nuclear Waste Cross Site Transfer Pump Operational Resonance Resolution

    SciTech Connect

    HAUCK, F.M.

    1999-12-01

    Two single-volute, multi-stage centrifugal pumps are installed at a nuclear waste transfer station operated by the Department of Energy in Hanford, WA. The two parallel 100% pumps are Variable Frequency Drive operated and designed to transport waste etc.

  15. Quality assessment of layer-structured semiconductor single crystals by nuclear quadruple resonance method

    NASA Astrophysics Data System (ADS)

    Samila, Andriy; Khandozhko, Alexander; Lastivka, Galina; Politansky, Leonid; Khandozhko, Victor

    2015-11-01

    A method for quality assessment of layer-structured semiconductor single crystals (InSe, GaSe, GaS) grown in evacuated ampoules by the Bridgman technique is proposed. For this purpose, nuclear quadruple resonance method with a consecutive scanning of the entire sample volume and evaluation of crystal perfection by the resulting spectra is used. Effective interaction between high-frequency field and crystal and, accordingly, restriction of scanning area of sample under study is provided with the use of a two-way saddle-shaped coil for a nuclear quadruple resonance spectrometer.

  16. Nuclear magnetic resonance micro-imaging in the investigation of plant cell metabolism.

    PubMed

    Köckenberger, W

    2001-04-01

    Micro-imaging based on nuclear magnetic resonance offers the possibility to map metabolites in plant tissues non-invasively. Major metabolites such as sucrose and amino acids can be observed with high spatial resolution. Stable isotope tracers, such as (13)C-labelled metabolites can be used to measure the in vivo conversion rates in a metabolic network. This review summarizes the different nuclear magnetic resonance micro-imaging techniques that are available to obtain spatially resolved information on metabolites in plants. A short general introduction into NMR imaging techniques is provided. Particular emphasis is given to the difficulties encountered when NMR micro-imaging is applied to plant systems.

  17. The Trojan Horse method for nuclear astrophysics: Recent results on resonance reactions

    SciTech Connect

    Cognata, M. La; Pizzone, R. G.; Spitaleri, C.; Cherubini, S.; Romano, S.; Gulino, M.; Tumino, A.; Lamia, L.

    2014-05-09

    Nuclear astrophysics aims to measure nuclear-reaction cross sections of astrophysical interest to be included into models to study stellar evolution and nucleosynthesis. Low energies, < 1 MeV or even < 10 keV, are requested for this is the window where these processes are more effective. Two effects have prevented to achieve a satisfactory knowledge of the relevant nuclear processes, namely, the Coulomb barrier exponentially suppressing the cross section and the presence of atomic electrons. These difficulties have triggered theoretical and experimental investigations to extend our knowledge down to astrophysical energies. For instance, indirect techniques such as the Trojan Horse Method have been devised yielding new cutting-edge results. In particular, I will focus on the application of this indirect method to resonance reactions. Resonances might dramatically enhance the astrophysical S(E)-factor so, when they occur right at astrophysical energies, their measurement is crucial to pin down the astrophysical scenario. Unknown or unpredicted resonances might introduce large systematic errors in nucleosynthesis models. These considerations apply to low-energy resonances and to sub-threshold resonances as well, as they may produce sizable modifications of the S-factor due to, for instance, destructive interference with another resonance.

  18. The Trojan Horse method for nuclear astrophysics: Recent results on resonance reactions

    NASA Astrophysics Data System (ADS)

    La Cognata, M.; Spitaleri, C.; Cherubini, S.; Gulino, M.; Lamia, L.; Pizzone, R. G.; Romano, S.; Tumino, A.

    2014-05-01

    Nuclear astrophysics aims to measure nuclear-reaction cross sections of astrophysical interest to be included into models to study stellar evolution and nucleosynthesis. Low energies, < 1 MeV or even < 10 keV, are requested for this is the window where these processes are more effective. Two effects have prevented to achieve a satisfactory knowledge of the relevant nuclear processes, namely, the Coulomb barrier exponentially suppressing the cross section and the presence of atomic electrons. These difficulties have triggered theoretical and experimental investigations to extend our knowledge down to astrophysical energies. For instance, indirect techniques such as the Trojan Horse Method have been devised yielding new cutting-edge results. In particular, I will focus on the application of this indirect method to resonance reactions. Resonances might dramatically enhance the astrophysical S(E)-factor so, when they occur right at astrophysical energies, their measurement is crucial to pin down the astrophysical scenario. Unknown or unpredicted resonances might introduce large systematic errors in nucleosynthesis models. These considerations apply to low-energy resonances and to sub-threshold resonances as well, as they may produce sizable modifications of the S-factor due to, for instance, destructive interference with another resonance.

  19. Nuclear magnetic and nuclear quadrupole resonance parameters of β-carboline derivatives calculated using density functional theory

    NASA Astrophysics Data System (ADS)

    Ahmadinejad, Neda; Tari, Mostafa Talebi

    2017-04-01

    A density functional theory (DFT) calculations using B3LYP/6-311++G( d,p) method were carried out to investigate the relative stability of the molecules of β-carboline derivatives such as harmaline, harmine, harmalol, harmane and norharmane. Calculated nuclear quadrupole resonance (NQR) parameters were used to determine the 14N nuclear quadrupole coupling constant χ, asymmetry parameter η and EFG tensor ( q zz ). For better understanding of the electronic structure of β-carboline derivatives, natural bond orbital (NBO) analysis, isotropic and anisotropic NMR chemical shieldings were calculated for 14N nuclei using GIAO method for the optimized structures. The NBO analysis shows that pyrrole ring nitrogen (N9) atom has greater tendency than pyridine ring nitrogen (N2) atom to participate in resonance interactions and aromaticity development in the all of these structures. The NMR and NQR parameters were studied in order to find the correlations between electronic structure and the structural stability of the studied molecules.

  20. Proton nuclear magnetic resonance studies of mast cell histamine

    SciTech Connect

    Rabenstein, D.L.; Ludowyke, R.; Lagunoff, D.

    1987-11-03

    The state of histamine in mast cells was studied by /sup 1/H NMR spectroscopy. Spectra were measured for histamine in situ in intact mast cells, for histamine in suspensions of mast cell granule matrices that had been stripped of their membranes, and for histamine in solutions of heparin. The /sup 1/H NMR spectrum of intact mast cells is relatively simple, consisting predominantly of resonances for intracellular histamine superimposed on a weaker background of resonances from heparin and proteins of the cells. All of the intracellular histamine contributes of the NMR signals, indicating it must be relatively mobile and not rigidly associated with the negatively charged granule matrix. Spectra for intracellular histamine and for histamine in granule matrices are similar, indicating the latter to be a reasonable model for the in situ situation. The dynamics of binding of histamine by granule matrices and by heparin are considerably different; exchange of histamine between the bulk water and the granule matrices is slow on the /sup 1/H NMR time scale, whereas exchange between the free and bound forms in heparin solution is fast. The chemical shifts of resonances for histamine in mast cells are pH dependent, decreasing as the intragranule pH increases without splitting or broadening. The results are interpreted to indicate that histamine in mast cells is relatively labile, with rapid exchange between histamine and pools of free histamine in water compartments confined in the granule matrix.

  1. Quantifying the passive gamma signal from spent nuclear fuel in support of determining the plutonium content in spent nuclear fuel with nondestructive assay

    SciTech Connect

    Fensin, Michael L; Tobin, Steven J; Menlove, Howard O; Swinhoe, Martyn T

    2009-01-01

    The objective of safeguarding nuclear material is to deter diversions of significant quantities of nuclear materials by timely monitoring and detection. There are a variety of motivations for quantifying plutonium in spent fuel (SF), by means of nondestructive assay (NDA), in order to meet this goal. These motivations include the following: strengthening the capabilities of the International Atomic Energy Agencies ability to safeguard nuclear facilities, shipper/receiver difference, input accountability at reprocessing facilities and burnup credit at repositories. Many NDA techniques exist for measuring signatures from SF; however, no single NDA technique can, in isolation, quantify elemental plutonium in SF. A study has been undertaken to determine the best integrated combination of 13 NDA techniques for characterizing Pu mass in spent fuel. This paper focuses on the development of a passive gamma measurement system in support the spent fuel assay system. Gamma ray detection for fresh nuclear fuel focuses on gamma ray emissions that directly coincide with the actinides of interest to the assay. For example, the 186-keV gamma ray is generally used for {sup 235}U assay and the 384-keV complex is generally used for assaying plutonium. In spent nuclear fuel, these signatures cannot be detected as the Compton continuum created from the fission products dominates the signal in this energy range. For SF, the measured gamma signatures from key fission products ({sup 134}Cs, {sup 137}Cs, {sup 154}Eu) are used to ascertain burnup, cooling time, and fissile content information. In this paper the Monte Carlo modeling set-up for a passive gamma spent fuel assay system will be described. The set-up of the system includes a germanium detector and an ion chamber and will be used to gain passive gamma information that will be integrated into a system for determining Pu in SF. The passive gamma signal will be determined from a library of {approx} 100 assemblies that have been

  2. The reaction gammap-->pi0gamma'p and the magnetic dipole moment of the Delta+ 1232 resonance.

    PubMed

    Kotulla, M; Ahrens, J; Annand, J R M; Beck, R; Caselotti, G; Fog, L S; Hornidge, D; Janssen, S; Krusche, B; McGeorge, J C; McGregor, I J D; Mengel, K; Messchendorp, J G; Metag, V; Novotny, R; Pfeiffer, M; Rost, M; Sack, S; Sanderson, R; Schadmand, S; Watts, D P

    2002-12-30

    The reaction gammap-->pi(0)gamma'p has been measured with the TAPS calorimeter at the Mainz Microtron accelerator facility MAMI for energies between sqrt[s]=1221-1331 MeV. The cross section's differential in angle and energy have been determined for the photon gamma' in three bins of the excitation energy. This reaction channel provides access to the magnetic dipole moment of the Delta(+)(1232) resonance and, for the first time, a value of mu(Delta(+))=[2.7(+1.0)(-1.3)(stat)+/-1.5(syst)+/-3(theor)]mu(N) has been extracted.

  3. Universal quantum control in zero-field nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Bian, Ji; Jiang, Min; Cui, Jiangyu; Liu, Xiaomei; Chen, Botao; Ji, Yunlan; Zhang, Bo; Blanchard, John; Peng, Xinhua; Du, Jiangfeng

    2017-05-01

    This paper describes a general method for the manipulation of nuclear spins in zero magnetic field. In the absence of magnetic fields, the spins lose the individual information on chemical shifts and inequivalent spins can only be distinguished by nuclear gyromagnetic ratios and spin-spin couplings. For spin-1/2 nuclei with different gyromagnetic ratios (i.e., different species) in zero magnetic field, we describe the scheme to realize a set of universal quantum logic gates, e.g., arbitrary single-qubit gates and a two-qubit controlled-not gate. This method allows for universal quantum control in systems which might provide promising applications in materials science, chemistry, biology, quantum information processing, and fundamental physics.

  4. Dynamical in situ nuclear-magnetic-resonance tensile apparatus

    NASA Astrophysics Data System (ADS)

    Hackelöer, H. J.; Kanert, O.; Tamler, H.; De Hosson, J. Th. M.

    1983-03-01

    A combination of a servohydraulic tensile machine and NMR pulse spectrometer is described enabling nuclear-spin relaxation rates to be recorded simultaneously with stress-strain data incorporating tension as well as compression of nonmetallic as well as of metallic samples. The data of the mechanical system are as follows: Maximum load: 5000 N; minimum deformation speed: 10 μm s-1, maximum deformation speed: 3×105 μm s-1; deformation stroke: digitally controlled between 1 and 8×103 μm; bandwidth: dc to 1 kHz; resolution: 2-4 μm; temperature conditions of the sample: from 80 to 570 K. The operation and performance of the system is described by means of experiments observing nuclear-spin relaxation rates which are induced by the movement of dislocations due to the finite deformation rate of the sample.

  5. Ex Luna Scientia! A New Paradigm for Nuclear Gamma-Ray Astrophysics

    NASA Astrophysics Data System (ADS)

    Miller, Richard Scott; Bonamente, M.; Ebbets, D.; Freelove, R.; Harwit, A.; Lawrence, D. J.; O'Brien, S.; Paciesas, W. S.; Young, C. A.

    2010-03-01

    The Lunar Occultation Observer (LOCO) is a new gamma-ray astrophysics mission concept being developed to probe the nuclear regime (( 0.1-10 MeV). LOCO will perform an all-sky survey of the Cosmos at nuclear energies, and will the have capability to address multiple high-priority science goals. Placed into lunar orbit, LOCO will utilize the Moon's unique environment to maximize performance relative to terrestrial-orbit endeavors with similar science goals. Specifically, LOCO will use the Moon to occult astrophysical sources as they rise and set along the lunar limb. The encoded temporal modulation will then be used to image the sky thereby enabling spectroscopic, time-variability, point- & extended-source analyses. This Lunar Occultation Technique (LOT) enables the excellent flux sensitivity, position, and energy resolution required of the next-generation nuclear astrophysics mission. In addition, occultation imaging eliminates the need for complex, position sensitive detectors. The LOCO concept is cost-effective, competitive, and has a straightforward and scaleable implementation. I will review the top-level mission concept, simulations and performance estimates, detector development efforts, mission implementation strategies and tradeoffs, as well as the astrophysics and secondary lunar science goals. This work was supported in part by National Aeronautics and Space Administration grants NNG06GF74G and National Science Foundation grant ATM-0421267. One author (RSM) also acknowledges support of the National Space Science & Technology Center through cooperative agreement grants NCC8-200 and NNM05AA22A.

  6. Contemporary research with nuclear resonance fluorescence at the S-DALINAC

    SciTech Connect

    Zweidinger, M.; Beck, T.; Beller, J.; Gayer, U.; Mertes, L.; Pai, H.; Pietralla, N.; Ries, P.; Romig, C.; Werner, V.

    2015-02-24

    In the last decades many nuclear resonance fluorescence experiments aiming for low-lying dipole excitations were performed at the Darmstadt High Intensity Photon Setup at S-DALINAC facility. On the electric dipole side, quadrupole-octupole coupled states and the Pygmy Dipole Resonance are of particular interest. On the magnetic dipole side, the so-called scissors mode is in the focus of interest. Furthermore, using the method of resonant self absorption, the decay behavior of J{sup π} = 1{sup −} states was investigated in {sup 140}Ce.

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

    NASA Astrophysics Data System (ADS)

    Seliger, J.; Žagar, V.

    2008-07-01

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

  8. Enantiodifferentiation through frequency-selective pure-shift (1)H nuclear magnetic resonance spectroscopy.

    PubMed

    Castañar, Laura; Pérez-Trujillo, Míriam; Nolis, Pau; Monteagudo, Eva; Virgili, Albert; Parella, Teodor

    2014-04-04

    A frequency-selective 1D (1) H nuclear magnetic resonance (NMR) experiment for the fast and sensitive determination of chemical-shift differences between overlapped resonances is proposed. The resulting fully homodecoupled (1) H NMR resonances appear as resolved 1D singlets without their typical J(HH) coupling constant multiplet structures. The high signal dispersion that is achieved is then exploited in enantiodiscrimination studies by using chiral solvating agents. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Invited Review Article: Instrumentation for nuclear magnetic resonance in zero and ultralow magnetic field.

    PubMed

    Tayler, Michael C D; Theis, Thomas; Sjolander, Tobias F; Blanchard, John W; Kentner, Arne; Pustelny, Szymon; Pines, Alexander; Budker, Dmitry

    2017-09-01

    We review experimental techniques in our laboratory for nuclear magnetic resonance (NMR) in zero and ultralow magnetic field (below 0.1 μT) where detection is based on a low-cost, non-cryogenic, spin-exchange relaxation free (87)Rb atomic magnetometer. The typical sensitivity is 20-30 fT/Hz(1/2) for signal frequencies below 1 kHz and NMR linewidths range from Hz all the way down to tens of mHz. These features enable precision measurements of chemically informative nuclear spin-spin couplings as well as nuclear spin precession in ultralow magnetic fields.

  10. Zero-field nuclear magnetic resonance spectroscopy of viscous liquids.

    PubMed

    Shimizu, Y; Blanchard, J W; Pustelny, S; Saielli, G; Bagno, A; Ledbetter, M P; Budker, D; Pines, A

    2015-01-01

    We report zero-field NMR measurements of a viscous organic liquid, ethylene glycol. Zero-field spectra were taken showing resolved scalar spin-spin coupling (J-coupling) for ethylene glycol at different temperatures and water contents. Molecular dynamics strongly affects the resonance linewidth, which closely follows viscosity. Quantum chemical calculations have been used to obtain the relative stability and coupling constants of all ethylene glycol conformers. The results show the potential of zero-field NMR as a probe of molecular structure and dynamics in a wide range of environments, including viscous fluids. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. [Nuclear magnetic resonance tomography of the temporomandibular joint].

    PubMed

    König, H; Spitzer, W J

    1986-05-01

    Because of its position, the temporomandibular joint is difficult to demonstrate by conventional radiological methods. Even the use of complex methods, such as arthro-tomography or CT, does not result in the satisfactory demonstration of the soft tissues and, in particular, of the articular disc. Magnetic resonance was carried out in 24 patients; it was possible to differentiate functional from morphological changes in the cartilage and these are discussed. Measurements were carried out during progressive opening of the mouth. This permits direct demonstration of reversible and irreversible cartilage displacement and of other changes in the joint and cartilages.

  12. High-performance gamma spectroscopy for equipment retrieval from Hanford high-level nuclear waste tanks

    NASA Astrophysics Data System (ADS)

    Troyer, Gary L.; Hillesand, K. E.; Goodwin, S. G.; Kessler, S. F.; Killian, E. W.; Legare, D.; Nelson, Joseph V., Jr.; Richard, R. F.; Nordquist, E. M.

    1999-01-01

    The cleanup of high level defense nuclear waste at the Hanford site presents several progressive challenges. Among these is the removal and disposal of various components from buried active waste tanks to allow new equipment insertion or hazards mitigation. A unique automated retrieval system at the tank provides for retrieval, high pressure washing, inventory measurement, and containment for disposal. Key to the inventory measurement is a three detector HPGe high performance gamma spectroscopy system capable of recovering data at up to ninety per cent saturation (200,000 counts per second). Data recovery is based on a unique embedded electronic pulser and specialized software to report the inventory. Each of the detectors have different shielding specified through Monte Carlo simulation with the MCNP program. This shielding provides performance over a dynamic range of eight orders of magnitude. System description, calibration issues and operational experiences are discussed.

  13. Observation of gamma-rays from fallout collected at Ibaraki, Japan, during the Fukushima nuclear accident.

    PubMed

    Saegusa, Jun; Kikuta, Yasuaki; Akino, Hitoshi

    2013-07-01

    Gamma-ray pulse height distributions were measured for a fallout sample collected at Ibaraki, Japan, during the Fukushima accident in March 2011. The fallout was collected in a pan of water and then evaporated to dryness on a stainless-steel holder. The sample was measured by a germanium detector three times over a year. In the pulse height distribution of the initial measurement, approximately 140 peaks were observed in the 50-2048 keV energy region. Most of these peaks were either total absorption peaks or sum peaks of Te, I or Cs isotopes. Unlike fallout samples at the past nuclear accidents, nuclides such as Ce and Ru were not detected whereas (110m)Ag was prominently observed. The radioactivity concentration of (137)Cs was determined to be at least 1.4×10(4) Bq m(-2), approximately 14% of which was attributed to rainout.

  14. Nuclear Material Accountability Applications of a Continuous Energy and Direction Gamma Ray Detector

    SciTech Connect

    David Gerts; Robert Bean; Marc Paff

    2010-07-01

    The Idaho National Laboratory has recently developed a detector system based on the principle of a Wilson cloud chamber that gives the original energy and direction to a gamma ray source. This detector has the properties that the energy resolution is continuous and the direction to the source can be resolved to desired fidelity. Furthermore, the detector has low power requirements, is durable, operates in widely varying environments, and is relatively cheap to produce. This detector is expected, however, to require significant time to perform measurements. To mitigate the significant time for measurements, the detector is expected to scale to very large sizes with a linear increase in cost. For example, the proof of principle detector is approximately 30,000 cm3. This work describes the technical results that lead to these assertions. Finally, the applications of this detector are described in the context of nuclear material accountability.

  15. The Complexation of the Na(super +) by 18-Crown-6 Studied via Nuclear Magnetic Resonance

    ERIC Educational Resources Information Center

    Peters, Steven J.; Stevenson, Cheryl D.

    2004-01-01

    A student friendly experiment that teaches several important concepts of modern nuclear magnetic resonance (NMR), like multinuclear capabilities, the NMR time scale, and time-averaged signals, is described along with some important concepts of thermo chemical equilibria. The mentioned experiment involves safe and inexpensive compounds, such as…

  16. Double-tuned single coil probe for nuclear magnetic resonance spectrometer

    SciTech Connect

    McKay, R.A.

    1984-05-01

    A double-tuned single coil probe for a nuclear magnetic resonance spectrometer having improved sensitivity is described comprising a double-tuned circuit means in which the low frequency irradiation is fed to a transmission line through an inductor means. The double-tuned circuit means of the invention may be remotely disposed from the magnetic field which results in greater sensitivity.

  17. Analyses of cocondensation of melamine and urea through formaldehyde with carbon 13 nuclear magnetic resonance spectroscopy

    Treesearch

    Tomita Bunchiro; Chung-Yun Hse

    1995-01-01

    The 13C-NMR (carbon 13 nuclear magnetic resonance) spectra of urea-formaldehyde (UF) resins, melamine-formaldehyde (MF) resins, and melamine-urea-formaldehyde (MUF) cocondensed resins synthesized under various conditions were taken with a frequency of 75 MHz. The main purpose was to investigate whether or not the occurrences of cocondensation...

  18. Analysis of cocondensation of melamine and urea through formaldehyde with carbon 13 nuclear magnetic resonance spectroscopy

    Treesearch

    Bunichiro Tomita; Chung-Yun Hse

    1995-01-01

    The 13C-NMR (carbon 13 nuclear magnetic resonance) spectra of urea-formaldehyde (UF) resins, melamine-formaldehyde (MF) resins, and melamine-urea-formaldehyde (MUF) cocondensed resins synthesized under various conditions were taken with a frequency of 75 MHz. The main purpose was to investigate whether or not the occurrences of cocondensation...

  19. The Effect of Electronic Paramagnetism on Nuclear Magnetic Resonance Frequencies in Metals

    DOE R&D Accomplishments Database

    Townes, C. H.; Herring, C.; Knight, W. D.

    1950-09-22

    Observations on the shifts of nuclear resonances in metals ( Li{sup 7}, Na{sup 23}, Cu {sup 63}, Be{sup 9}, Pb{sup 207}, Al{sup 27}, and Ca{sup 69} ) due to free electron paramagnetism; comparison with theoretical values.

  20. An Accessible Two-Dimensional Solution Nuclear Magnetic Resonance Experiment on Human Ubiquitin

    ERIC Educational Resources Information Center

    Rovnyak, David; Thompson, Laura E.

    2005-01-01

    Solution-state nuclear magnetic resonance (NMR) is an invaluable tool in structural and molecular biology research, but may be underutilized in undergraduate laboratories because instrumentation for performing structural studies of macromolecules in aqueous solutions is not yet widely available for use in undergraduate laboratories. We have…

  1. The Isoscalar Giant Dipole Resonance in {sup 20}Pb, {sup 90}Zr and the Nuclear Compressibility

    SciTech Connect

    Yildirim, Serbulent; Koeroglu, Ulas

    2008-11-11

    The isoscalar giant dipol resonance (ISGDR) in finite nuclei is studied within the framework of a relativistic transport approach. The excitation energies of spherical {sup 90}Zr and {sup 208}Pb nuclei are obtained for different quantum hydrodynamical Lagrangian parametrization. The sensitivity of ISGDR excitation energy on the nuclear bulk to surface properties are also investigated.

  2. MEMS-based force-detected nuclear magnetic resonance spectrometer for in situ planetary exploration

    NASA Technical Reports Server (NTRS)

    George, T.; Leskowitz, G.; Madsen, L.; Weitekamp, D.; Tang, W.

    2000-01-01

    Nuclear Magnetic resonance (NMR) is a well-known spectroscopic technique used by chemists and is especially powerful in detecting the presence of water and distinguishing between arbitrary physisorbed and chemisorbed states. This ability is of particular importance in the search for extra-terrestrial life on planets such as Mars.

  3. Quantitative Analysis of Nail Polish Remover Using Nuclear Magnetic Resonance Spectroscopy Revisited

    ERIC Educational Resources Information Center

    Hoffmann, Markus M.; Caccamis, Joshua T.; Heitz, Mark P.; Schlecht, Kenneth D.

    2008-01-01

    Substantial modifications are presented for a previously described experiment using nuclear magnetic resonance (NMR) spectroscopy to quantitatively determine analytes in commercial nail polish remover. The revised experiment is intended for a second- or third-year laboratory course in analytical chemistry and can be conducted for larger laboratory…

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

    USDA-ARS?s Scientific Manuscript database

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

  5. Sealed magic angle spinning nuclear magnetic resonance probe and process for spectroscopy of hazardous samples

    SciTech Connect

    Cho, Herman M.; Washton, Nancy M.; Mueller, Karl T.; Sears, Jr., Jesse A.; Townsend, Mark R.; Ewing, James R.

    2016-06-14

    A magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) probe is described that includes double containment enclosures configured to seal and contain hazardous samples for analysis. The probe is of a modular design that ensures containment of hazardous samples during sample analysis while preserving spin speeds for superior NMR performance and convenience of operation.

  6. An Accessible Two-Dimensional Solution Nuclear Magnetic Resonance Experiment on Human Ubiquitin

    ERIC Educational Resources Information Center

    Rovnyak, David; Thompson, Laura E.

    2005-01-01

    Solution-state nuclear magnetic resonance (NMR) is an invaluable tool in structural and molecular biology research, but may be underutilized in undergraduate laboratories because instrumentation for performing structural studies of macromolecules in aqueous solutions is not yet widely available for use in undergraduate laboratories. We have…

  7. Hepatic Metabolism of Perfluorinated Carboxylic Acids and Polychlorotrifluoroethylene: A Nuclear Magnetic Resonance Investigation in Vivo

    DTIC Science & Technology

    1992-01-24

    metabolism of perfluorooctanoic acid (PFOA) and perfluorodecanoic acid (PFDA) in rats. These studies are now complete and a manuscript was submitted to...SUBTITLE S. FUNDING NUMBERS Hepatic Metabolism of Perfluorinated Carboxylic Acids and Polychlorotrifluoroethylene: A Nuclear Magnetic Resonance...describes recent results of studies designed to investigate the metabolic effects of perfluoro- carboxylic acids on liver carbohydrate and high-energy

  8. Interaction between adrenaline and dibenzo-18-crown-6: Electrochemical, nuclear magnetic resonance, and theoretical study

    NASA Astrophysics Data System (ADS)

    Yu, Zhang-Yu; Liu, Tao; Wang, Xue-Liang

    2014-12-01

    The interaction between adrenaline (Ad) and dibenzo-18-crown-6 (DB18C6) was studied by cyclic voltammetry, nuclear magnetic resonance spectroscopy, and the theoretical calculations, respectively. The results show that DB18C6 will affect the electron transfer properties of Ad. DB18C6 can form stable supramolecular complexes with Ad through ion-dipole and hydrogen bond interactions.

  9. Exploration of the Use of Nuclear Magnetic Resonance for the Study of Ricin Toxicity in Cells

    DTIC Science & Technology

    2009-04-01

    ricin. 15. SUBJECT TERMS 3T3 Cells Ricinus communis Cell Toxicity Nuclear Magnetic Resonance NMR Ricin 16. SECURITY CLASSIFICATION OF: a. REPORT u...Ricin Preparation. The Ricin communis agglutinin II (ricin) stock solution was prepared by dialyzing ricin (Vector Laboratories, Burlingame, CA

  10. A Noninvasive Method to Study Regulation of Extracellular Fluid Volume in Rats Using Nuclear Magnetic Resonance

    EPA Science Inventory

    Time-domain nuclear magnetic resonance (TD-NMR)-based measurement of body composition of rodents is an effective method to quickly and repeatedly measure proportions of fat, lean, and fluid without anesthesia. TD-NMR provides a measure of free water in a living animal, termed % f...

  11. Quantitative Analysis of Nail Polish Remover Using Nuclear Magnetic Resonance Spectroscopy Revisited

    ERIC Educational Resources Information Center

    Hoffmann, Markus M.; Caccamis, Joshua T.; Heitz, Mark P.; Schlecht, Kenneth D.

    2008-01-01

    Substantial modifications are presented for a previously described experiment using nuclear magnetic resonance (NMR) spectroscopy to quantitatively determine analytes in commercial nail polish remover. The revised experiment is intended for a second- or third-year laboratory course in analytical chemistry and can be conducted for larger laboratory…

  12. A Noninvasive Method to Study Regulation of Extracellular Fluid Volume in Rats Using Nuclear Magnetic Resonance

    EPA Science Inventory

    Time-domain nuclear magnetic resonance (TD-NMR)-based measurement of body composition of rodents is an effective method to quickly and repeatedly measure proportions of fat, lean, and fluid without anesthesia. TD-NMR provides a measure of free water in a living animal, termed % f...

  13. Perspective on Advances in Resonance-Region Nuclear Modeling and Opportunities for Future Research

    SciTech Connect

    Dunn, Michael E; Larson, Nancy M; Derrien, Herve; Leal, Luiz C

    2007-01-01

    The advent of high-fidelity radiation-transport modeling capabilities, coupled with the need to analyze complex nuclear systems, has served to emphasize the importance of high-precision cross section data, including the associated covariance information. Due to the complex nature of resonance-region interactions, cross section data cannot be calculated directly from theory; rather, high-precision resonance-region cross section measurements must be made at facilities such as the Oak Ridge Electron Linear Accelerator (ORELA) at Oak Ridge National Laboratory (ORNL), Geel Electron Linear Accelerator (GELINA), Rensselaer Polytechnic Institute (RPI). To extract accurate cross section data from these measurements, detailed nuclear modeling of the measured data is performed to parameterize the cross section behavior in the resonance range. The objective of this paper is to highlight recent advances in resonance-region nuclear modeling with particular emphasis on the covariance analysis capabilities. Opportunities for future research are identified in an effort to stimulate further advances in the state of the art nuclear modeling capabilities.

  14. Prototype explosives detection system based on nuclear resonance absorption in nitrogen

    SciTech Connect

    Morgado, R.E.; Arnone, G.; Cappiello, C.C.; Gardner, S.D.; Hollas, C.L.; Ussery, L.E.; White, J.M.; Zahrt, J.D.; Krauss, R.A.

    1993-12-01

    A-prototype explosives detection system that was developed for experimental evaluation of a nuclear resonance absorption techniques is described. The major subsystems are a proton accelerator and beam transport, high-temperature proton target, an airline-luggage tomographic inspection station, and an image-processing/detection- alarm subsystem. The detection system performance, based on a limited experimental test, is reported.

  15. The Complexation of the Na(super +) by 18-Crown-6 Studied via Nuclear Magnetic Resonance

    ERIC Educational Resources Information Center

    Peters, Steven J.; Stevenson, Cheryl D.

    2004-01-01

    A student friendly experiment that teaches several important concepts of modern nuclear magnetic resonance (NMR), like multinuclear capabilities, the NMR time scale, and time-averaged signals, is described along with some important concepts of thermo chemical equilibria. The mentioned experiment involves safe and inexpensive compounds, such as…

  16. In vivo imaging of the rat anatomy with nuclear magnetic resonance.

    PubMed

    Hansen, G; Crooks, L E; Davis, P; De Groot, J; Herfkens, R; Margulis, A R; Gooding, C; Kaufman, L; Hoenninger, J; Arakawa, M; McRee, R; Watts, J

    1980-09-01

    Live rats were imaged by nuclear magnetic resonance (NMR). These images demonstrated fine detail and high object contrast. Motion artifacts are not apparent in 4-minute images, and major blood vessels are demonstrated as regions of low signal intensity because of blood flow. Selective contrast enhancement is possible by varying NMR imager accumulation parameters.

  17. Time domain-nuclear magnetic resonance study of chars from southern hardwoods

    Treesearch

    Thomas Elder; Nicole Labbe; David Harper; Timothy Rials

    2006-01-01

    Chars from the thermal degradation of silver maple (Acer saccharinum), red maple (Acer rubrum), sugar maple (Acer saccharum), and white oak (Quercus spp.), performed at temperatures from 250 to 350 oC, were examined using time domain-nuclear magnetic resonance...

  18. Xenobiotic Monitoring in Plants by 19F and 1H Nuclear Magnetic Resonance Imaging and Spectroscopy

    PubMed Central

    Rollins, Andrew; Barber, Jill; Elliott, Raymond; Wood, Brian

    1989-01-01

    19F and 1H nuclear magnetic resonance imaging and spectroscopy have been used to monitor the uptake of trifluoroacetic acid in stems and leaves of Lycopersicon esculentum. The movement and location of a xenobiotic have been demonstrated in vivo by a noninvasive technique. Images Figure 5 PMID:16667169

  19. Nuclear magnetic resonance linewidth and spin diffusion in {sup 29}Si isotopically controlled silicon

    SciTech Connect

    Hayashi, Hiroshi; Itoh, Kohei M.; Vlasenko, Leonid S.

    2008-10-15

    A nuclear magnetic resonance (NMR) study was performed with n-type silicon single crystals containing {sup 29}Si isotope abundance f ranges from 1.2% to 99.2%. The nuclear spin diffusion coefficient D has been determined from the linewidth of significantly enhanced {sup 29}Si NMR signals utilizing a developed dynamic nuclear polarization (DNP) method. The {sup 29}Si NMR linewidth depends linearly on f, at least when f<10%, and approaches {proportional_to}f{sup 1/2} dependence when f>50%. The estimated {sup 29}Si nuclear spin diffusion time T{sub sd} between phosphorus atoms used for DNP is more than ten times shorter than the nuclear polarization time T{sub 1}{sup p} of {sup 29}Si nuclei around phosphorus. Therefore, the regime of 'rapid spin diffusion' is realized in the DNP experiments.

  20. Structural analysis of strained quantum dots using nuclear magnetic resonance.

    PubMed

    Chekhovich, E A; Kavokin, K V; Puebla, J; Krysa, A B; Hopkinson, M; Andreev, A D; Sanchez, A M; Beanland, R; Skolnick, M S; Tartakovskii, A I

    2012-10-01

    Strained semiconductor nanostructures can be used to make single-photon sources, detectors and photovoltaic devices, and could potentially be used to create quantum logic devices. The development of such applications requires techniques capable of nanoscale structural analysis, but the microscopy methods typically used to analyse these materials are destructive. NMR techniques can provide non-invasive structural analysis, but have been restricted to strain-free semiconductor nanostructures because of the significant strain-induced quadrupole broadening of the NMR spectra. Here, we show that optically detected NMR spectroscopy can be used to analyse individual strained quantum dots. Our approach uses continuous-wave broadband radiofrequency excitation with a specially designed spectral pattern and can probe individual strained nanostructures containing only 1 × 10(5) quadrupole nuclear spins. With this technique, we are able to measure the strain distribution and chemical composition of quantum dots in the volume occupied by the single confined electron. The approach could also be used to address problems in quantum information processing such as the precise control of nuclear spins in the presence of strong quadrupole effects.