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Consistent Data Assimilation of Structural Isotopes: 23Na and 56Fe

Description: A new approach is proposed, the consistent data assimilation, that allows to link the integral data experiment results to basic nuclear parameters employed by evaluators to generate ENDF/B point energy files in order to improve them. Practical examples are provided for the structural materials 23Na and 56Fe. The sodium neutron propagation experiments, EURACOS and JANUS-8, are used to improve via modifications of 23Na nuclear parameters (like scattering radius, resonance parameters, Optical model parameters, Statistical Hauser-Feshbach model parameters, and Preequilibrium Exciton model parameters) the agreement of calculation versus experiments for a series of measured reaction rate detectors slopes. For the 56Fe case the EURACOS and ZPR3 assembly 54 are used. Results have shown inconsistencies in the set of nuclear parameters used so that further investigation is needed. Future work involves comparison of results against a more traditional multigroup adjustments, and extension to other isotope of interest in the reactor community.
Date: September 1, 2010
Creator: Palmiotti, Giuseppe
Partner: UNT Libraries Government Documents Department

Preliminary Feasibility Study of Using Solid-State Nuclear Magnetic Resonance Spectroscopy to Characterize Hanford Tank Waste Solids

Description: This report describes experiments performed in FY 2001 to examine the feasibility of using nuclear magnetic resonance (NMR) spectroscopy to characterize Hanford tank sludge solids. The results demonstrate the potential utility of magic-angle spinning solid-state NMR spectroscopy for this purpose. We have shown that 27Al NMR signals can be easily detected in samples simulating the compositions of Hanford tank sludge solids. Different Al-containing species can be distinguished on the basis of a number of characteristics, including resonance frequency, lineshape, and response to excitation pulse length of the 27Al NMR signal. This work also indicates that 23Na NMR can likely be used to identify specific Na-containing phases present in tank wastes. It is expected that other NMR-active nuclides can be probed for information about specific phases present in tank-waste solids.
Date: October 31, 2001
Creator: Cho, Herman M
Partner: UNT Libraries Government Documents Department

High-Resolution NMR of Quadrupolar Nuclei in the Solid State

Description: This dissertation describes recent developments in solid state nuclear magnetic resonance (NMR), for the most part involving the use of dynamic-angle spinning (DAS) NMR to study quadrupolar nuclei. Chapter 1 introduces some of the basic concepts and theory that will be referred to in later chapters, such as the density operator, product operators, rotations, coherence transfer pathways, phase cycling, and the various nuclear spin interactions, including the quadrupolar interaction. Chapter 2 describes the theory behind motional averaging experiments, including DAS, which is a technique where a sample is spun sequentially about two axis oriented at different angles with respect to the external magnetic field such that the chemical shift and quadrupolar anisotropy are averaged to zero. Work done on various rubidium-87 salts is presented as a demonstration of DAS. Chapter 3 explains how to remove sidebands from DAS and magic-angle spinning (MAS) experiments, which result from the time-dependence of the Hamiltonian under sample spinning conditions, using rotor-synchronized {pi}-pulses. Data from these experiments, known as DAH-180 and MAH-180, respectively, are presented for both rubidium and lead salts. In addition, the applicability of this technique to double rotation (DOR) experiments is discussed. Chapter 4 concerns the addition of cross-polarization to DAS (CPDAS). The theory behind spin locking and cross polarizing quadrupolar nuclei is explained and a method of avoiding the resulting problems by performing cross polarization at 0{sup o} (parallel) with respect to the magnetic field is presented. Experimental results are shown for a sodium-23 compound, sodium pyruvate, and for oxygen-17 labeled L-akmine. In Chapter 5, a method for broadening the Hartmann-Hahn matching condition under MAS, called variable effective field cross-polarization (VEFCI?), is presented, along with experimental work on adamantane and polycarbonate.
Date: November 30, 1995
Creator: Gann, Sheryl Lee
Partner: UNT Libraries Government Documents Department

ACTIVATION CROSS SECTION OF Na$sup 23$ AROUND 3 KEV

Description: The activation cross section of sodium in the range from thermal energy through the 3-kev resonance is generally assumed to be given by the one-level BreitWigner formula, the GAMMA /sub gamma / being selected to describe correctly the known thermal absorption cross section. The contribution of this resonance to the resonance activation integral then turns out to be 0.12 barns. This somewhat indirectly inferred value is considerably larger than the value given by Dancoff et al., in an old paper, the latter value being based on experimental work. It is shown in the present memo, that Dancoff's actual measurements are quite consistent with the Breit-Wigner formula and the above mentioned GAMMA /sub gamma /. The discrepancy is a result of Dancoff's transition from the actual measurements to the resonance integral, this transition being based on data that is now obsolete. (auth)
Date: February 1, 1957
Creator: Ergen, W.K.
Partner: UNT Libraries Government Documents Department

Development of a magnetic resonance sensor for on-line monitoring of {sup 99}Tc and {sup 23}Na in tank waste cleanup processes: Final report and implementation plan

Description: In response to US Department of Energy (DOE) requirements for advanced cross-cutting technologies, Argonne National Laboratory is developing an on-line sensor system for the real-time monitoring of {sup 99}Tc and {sup 23}Na in various locations throughout radioactive-waste processing facilities. Based on nuclear magnetic resonance spectroscopy, the highly automated sensor system can provide near-real-time response with minimal sampling. The technology, in the form of a flow-through nuclear-magnetic-resonance-based on-line process sensing and control system, can rapidly monitor {sup 99}Tc speciation and concentration (from 0.1 molar to 10 micro molar) in the feedstocks and eluents of radioactive-waste treatment processes. The system is nonintrusive, capable of withstanding harsh plant environments, and reasonably immune to contaminants. Furthermore, the system is capable of operating over large variations in pH, conductivity, and salinity. This document describes design parameters, results from sensitivity studies, and initial results obtained from oxidation-reduction studies that were conducted on technetium standards and waste specimens obtained from DOE's Hanford site. A cursory investigation of the system's capabilities to monitor {sup 23}Na at high concentrations are also reported, as are descriptions of site requirements, implementation recommendations, and testing techniques.
Date: February 24, 2000
Creator: Dieckman, S. L.; Jendrzejczyk, J. A. & Raptis, A. C.
Partner: UNT Libraries Government Documents Department

SB3. Experiment on secondary gamma-ray production cross sections averaged over a fast-neutron spectrum for each of 13 different elements plus a stainless steel

Description: The experimental and calculational details for a CSEWG integral data testing shielding experiment are presented. This particular experiment measured the secondary gamma-ray production cross sections averaged over a fast-neutron spectrum for iron, oxygen, sodium, aluminum, copper, titanium, calcium, potassium, silicon, nickel, zinc, barium, sulfur, and a type 321 stainless steel. The gamma-ray production cross sections were binned into 0.5-MeV wide gamma-ray energy intervals. 29 tables, 1 figure (auth)
Date: January 1, 1976
Creator: Maerker, R.E.
Partner: UNT Libraries Government Documents Department

Resonance Integrals and Self-Shielding Factors for Detector Foils

Description: >Effective activation resonance integrals for thin and thick foils in an isotropic neutron flux were measured by a cadmium ratio method. Gold was used as a standard. Values obtained for dilute resonance integrals in barns, not including 1/v capture, were: Au/sup 197/, 1390 plus or minus 40 (Reference); U/ sup 238/ capture, 280 plus or minus 10; Cu/sup 63/, 3.17 plus or minus 0.18; Cu/sup 65/, 1.39 plus or minus 0.22; Mo/sup 98/, 9.9 plus or minus 1.1; Mo/sup 100/, 4.06 plus or minus 0.23; W/sup 186/, 476 plus or minus 50; and Na/sup 23/ , 0.075 plus or minus 0.010. Dilute resonance integrals including 1/v capture above 0.60 ev were: U/sup 235/ fission, 263 plus or minus 9 and In is, 3200 plus or minus 100. These resonance integrals and the measured resonance flux self-shielding factors were generally in good agreement with calculations. However, the two isotopes of molybdenum appeared to have major contributions to their resonance integrals from nontabulated resonances. Special methods used with various foils are described. (auth)
Date: January 1, 1963
Creator: Baumann, N. P.
Partner: UNT Libraries Government Documents Department

Applications of high resolution NMR to geochemistry: crystalline, glass, and molten silicates

Description: The nuclear spin interactions and the associated quantum mechanical dynamics which are present in solid state NMR are introduced. A brief overview of aluminosilicate structure is presented and crystalline structure is then reviewed, with emphasis on the contributions made by /sup 29/Si NMR spectroscopy. The local structure of glass aluminosilicates as observed by NMR, is presented with analysis of the information content of /sup 29/Si spectra. A high-temperature (to 1300/sup 0/C) NMR spectroscopic investigation of the local environment and dynamics of molecular motion in molten aluminosilicates is described. A comparison is made of silicate liquid, glass, and crystalline local structure. The atomic and molecular motions present in a melt are investigated through relaxation time (T/sub 1/ and T/sub 2/) measurements as a function of composition and temperature for /sup 23/Na and /sup 29/Si.
Date: November 1, 1985
Creator: Schneider, E.
Partner: UNT Libraries Government Documents Department

SB2. Experiment on secondary gamma-ray production cross sections arising from thermal-neutron capture in each of 14 different elements plus a stainless steel

Description: The experimental and calculational details for a CSEWG integral data testing shielding experiment are presented. This particular experiment measured the secondary gamma-ray production cross sections arising from thermal-neutron capture in iron, nitrogen, sodium, aluminum, copper, titanium, calcium, potassium, chlorine, silicon, ickel, zinc, barium, sulfur and a type 321 stainless steel. 1 figure, 30 tables (auth)
Date: January 1, 1976
Creator: Maerker, R.E.
Partner: UNT Libraries Government Documents Department

Evaluation of cross sections for neutron-induced reactions in sodium. [10/sup -5/ eV to 20 MeV]

Description: An evaluation of the neutron-induced cross sections of /sup 23/Na has been done for the energy range from 10/sup -5/ eV to 20 MeV. All significant cross sections are given, including differential cross sections for production of gamma rays. The recommended values are based on experimental data where available, and use results of a consistent model code analysis of available data to predict cross sections where there are no experimental data. This report describes the evaluation that was submitted to the Cross Section Evaluation Working Group (CSEWG) for consideration as a part of the Evaluated Nuclear Data File, Version V, and subsequently issued as MAT 1311. 126 references, 130 figures, 14 tables.
Date: September 1, 1980
Creator: Larson, D.C.
Partner: UNT Libraries Government Documents Department

Populations of excited states and reaction mechanisms in the emission of complex fragments

Description: Cross sections for emission of complex fragments (Z>2) in their ground and excited states are presented for several heavy-ion reactions at bombarding energies above 10 MeV/nucleon. Data presented are mostly on the cross sections extracted by {gamma}-ray techniques. It is shown that a simple statistical approach to associate the ratio, of cross sections for excited states and ground states, to the temperature of the emitter fails to give the expected temperatures. However, it is shown that this is mostly due to the fact that the fragments that {gamma} decay are secondary fragments, produced by the particle decay of the primary emitted complex fragments. A Hauser-Feshbach analysis accounts well for the cross sections and extracted temperatures. 22 refs., 6 figs.
Date: January 1, 1990
Creator: Gomez del Campo, J.
Partner: UNT Libraries Government Documents Department

Coplanarity of two-proton emissions in 400 MeV/nucleon Ne + NaF, Pb reactions

Description: Two-proton coincidence spectra have been measured in a wide kinematical range for /sup 20/Ne + NaF and /sup 20/Ne + Pb collisions at 400 MeV/nucleon. Coplanar-type correlations show different feature between Ne + NaF and Ne + Pb target reactions. A strong in-plane correlation, which correspond to quasi-elastic scatterings (QES) of nucleons, was observed in wide angular range (15 to 90/sup 0/) in NaF target collisions. Angular distributions of QES were reproduced reasonably well by a single nucleon-nucleon scattering model. Enhancement of the QES at momentum transfer around t = 2 - 3m/sub ..pi../, which is predicted as an indication of pionic instability, was not observed. In Ne + Pb collisions, an azimuthally asymmetric emission of particles with respect to the beam axis were implied by the anti-coplanar correlation. A new type of coplanar correlation between the emission angle and the momentum suggests a back-to-back emission of projectile and target nucleons. 8 references, 8 figures.
Date: October 1, 1984
Creator: Tanihata, Isao
Partner: UNT Libraries Government Documents Department

Spin-mapping of coal structures with ESE and ENDOR

Description: The overall goal of this project is the development of nondestructive techniques for studying the molecular structure of coal by probing the chemical environment of naturally occurring unpaired electrons with a variety of electron magnetic resonance spectroscopies. One exceptionally promising method for investigating molecular structure in complex solids possessing unpaired electrons is Electron Spin Echo Envelope Modulation (ESEEM) spectroscopy. Currently the aim of our S-band ESEEM work is to develop better methods for the interpretation of multifrequency ESEEM data. This problem is extremely difficult, especially for modulation resulting from quadrupolar nuclei (l > 1/2) such as {sup 33}S, {sup 14}N, and {sup 23}Na. We are pursuing two closely related paths toward this goal. One part of this effort is the development of classification system which would make ESEEM spectra more amenable to a preliminary interpretation by visual inspection. This report describes the testing of some of the capabilities of our recently constructed ESE spectrometer by carrying out a detailed investigation of the molecule DPPH, diphenylpicrylhydrazyl, a well-known stable free radical frequently used to test and tune up electron paramagnetic resonance spectrometers, but details of the nitrogen substituents on one of its aromatic rings have been uncertain and, in fact, the focus of a bit of controversy. It therefore made an excellent subject to select for this test. 14 refs., 2 figs.
Date: June 1, 1990
Creator: Belford, R.L. & Clarkson, R.B.
Partner: UNT Libraries Government Documents Department

An investigation of catalytic active phase-support interactions by IR, NMR and x-ray absorption spectroscopies

Description: Active catalytic phases (metal, mixed metals, oxide or mixed oxides) interacting with oxide support on which the active phase is dispersed can affect the percentage exposed, the morphology of supported particles, the degree of reducibility of cations, etc., in a variety of ways. Our objective is to characterize the physical chemistry of the active phase-oxide support interaction by spectroscopic methods and to correlate this structure with catalytic function. Two catalytic systems and their associated techniques (x-ray absorption and NMR) are discussed in this progress report. Firstly, the interaction of Pt-Ni supported on silica and L-zeolite are characterized and compared by x-ray absorption spectroscopy (EXAFS). Secondly, we present both experimental and calculational developments of NMR for the investigation of amorphous silica-alumina catalysts and/or supports.
Date: September 1, 1992
Creator: Haller, G.L.
Partner: UNT Libraries Government Documents Department

Pion source parameters in heavy ion collisions

Description: Following the early work of Goldhaber, Lee, and Pais, many experiments have used the momentum correlations between identical bosons to determine the space-time extent of the pion source for various reactions between elementary hadrons. This technique, known as intensity interferometry, has recently been applied to nuclear collisions at both intermediate and very high energies. Here we report on measurements of the radius and lifetime of the pion source in the reactions 1.8 A GeV /sup 40/Ar + KCl ..-->.. 2..pi../sup +-/ + X, 1.8 A GeV /sup 20/Na + NaF ..-->.. 2..pi../sup -/ + X, and 1.71 A GeV /sup 56/Fe + Fe ..-->.. 2..pi../sup -/ + X. 11 references.
Date: December 1, 1984
Creator: Crowe, K.M.; Bistirlich, J.A.; Bossingham, R.R.; Bowman, H.R.; Clawson, C.W.; Frankel, K.A. et al.
Partner: UNT Libraries Government Documents Department

Applications of carbon-13 and sodium-23 NMR in the study of plants, animal, and human cells

Description: Carbon-13 and sodium-23 NMR have been applied to the study of a variety of plant, animal and human cell types. Sodium NMR, in combination with dysprosium shift reagents, has been used to monitor sodium transport kinetics in salt-adapted, and non-adapted cells of P. milliaceum and whole D. spicata plants. The sodium content of human erythrocytes and leukemic macrophages was measured. Carbon-13 NMR was used to determine the structure and metabolism of rat epididymal fat pad adipocytes in real time. Insulin and isoproterenol-stimulated triacylglycerol turnover could be monitored in fat cell suspensions. (1-/sup 13/C) glucose was used as a substrate to demonstrate futile metabolic cycling from glucose to glycerol during lypolysis. Cell wall polysaccharide synthesis was followed in suspensions of P. milliaceum cells using (1-/sup 13/C) glucose as a precursor. These results illustrate the wide range of living systems which are amenable to study with NMR. 14 refs., 21 figs.
Date: January 1, 1984
Creator: Sillerud, L.O.; Heyser, J.W.; Han, C.H. & Bitensky, M.W.
Partner: UNT Libraries Government Documents Department