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1

Nuclear quadrupole resonance studies in semi-metallic structures  

NASA Technical Reports Server (NTRS)

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.

Murty, A. N.

1974-01-01

2

Density functional theory calculations of nuclear quadrupole coupling constants with calibrated 14N quadrupole moments  

NASA Astrophysics Data System (ADS)

Density functional calculations of the electric field gradient tensor at the nitrogen nucleus in 13 test molecules, containing 14 nitrogen sites, have been performed using the linear combination of Gaussian-type orbital Kohn-Sham density functional theory (LCGTO-KSDFT) approach. Local and gradient corrected functionals were used for all-electron calculations. All the molecular structures were optimized at their respective levels of theory with extended basis sets. Calibrated 14N nuclear quadrupole moments were obtained through a fitting procedure between calculated electric field gradients and experimental nuclear quadrupole coupling constants of the test set of molecules for each basis set and functional considered. With these calibrated 14N nuclear quadrupole moments, the nuclear quadrupole coupling constants of the following selected systems were determined: fluoromethylisonitrile, pyridine, pyrrole, imadazole, pyrazole, 1,8-bis(dimethyl-amino)naphthalene, cyclotetramethylenetetranitramine, cocaine and heroin.

Sicilia, E.; de Luca, G.; Chiodo, S.; Russo, N.; Calaminici, P.; Koster, A. M.; Jug, K.

3

Explosives detection by nuclear quadrupole resonance (NQR)  

NASA Astrophysics Data System (ADS)

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.

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

1994-10-01

4

Nuclear Charge Radii and Electric Quadrupole Moments  

E-print Network

Isotope shifts of the mean square radii (MSR) and electric quadrupole moments of even-even nuclei with 20particle Nilsson potential with the Seo set of correction term parameters, the pairing forces in the BCS formalism and a long range interaction in the local approximation are used. A collective hamiltonian is obtained using a generator coordinate method (GCM) with the gaussian overlap approximation (GOA). A potential energy of the nucleus consists of a microscopic-macroscopic Strutinsky energy and a zero point vibrational term. A liquid droplet model is used as the macroscopic part of the potential. A BCS wave function is taken as a generator function and two collective variables, quadrupole and hexadecapole deformations, serve as the generator coordinates.

Nerlo-Pomorska, B; Nerlo-Pomorska, Bozena; Mach, Beata

1993-01-01

5

Nuclear Charge Radii and Electric Quadrupole Moments  

E-print Network

Isotope shifts of the mean square radii (MSR) and electric quadrupole moments of even-even nuclei with 20particle Nilsson potential with the Seo set of correction term parameters, the pairing forces in the BCS formalism and a long range interaction in the local approximation are used. A collective hamiltonian is obtained using a generator coordinate method (GCM) with the gaussian overlap approximation (GOA). A potential energy of the nucleus consists of a microscopic-macroscopic Strutinsky energy and a zero point vibrational term. A liquid droplet model is used as the macroscopic part of the potential. A BCS wave function is taken as a generator function and two collective variables, quadrupole and hexadecapole deformations, serve as the generator coordinates.

Bozena Nerlo-Pomorska; Beata Mach

1993-11-24

6

Table of Nuclear Magnetic Dipole and Electric Quadrupole Moments  

E-print Network

of atomic nuclei throughout the periodic table. To aid identification of the states, their excitation energyTable of Nuclear Magnetic Dipole and Electric Quadrupole Moments N.J.Stone, Oxford Physics, Clarendon Laboratory Parks Road, OXFORD OX1 3PU U.K. This Table is a compilation of experimental

7

Spectra of nuclear quadrupole resonance in vitreous semiconductors  

SciTech Connect

The method of nuclear quadrupole resonance is used to study the chalcogenide semiconductors with compositions As{sub 2}Se{sub 3} and As{sub 14}Sb{sub 4}Se{sub 27}. It is shown that partial crystallization occurs in a sample of vitreous As{sub 2}Se{sub 3} kept for a long time at room temperature; as a result, a change in the shape of the spectrum of the nuclear quadrupole resonance is observed. The {sup 75}As spectrum in vitreous As{sub 14}Sb{sub 4}Se{sub 27} at a temperature of 77 K is measured for the first time. It is assumed that the {sup 121}Sb or {sup 123}Sb nuclei can contribute to the broad line of the quadrupole resonance. It is shown that the use of the nuclear spin-echo Fourier-transform mapping spectroscopy for reconstruction of very broad lines of the nuclear quadrupole resonance provides no advantages compared to the method of reconstruction based on the points in the integrated intensity of the echo signals.

Korneva, I. P., E-mail: kornev@albertina.ru; Sinyavskii, N. Ya. [Baltic State Academy (Russian Federation); Ostafin, M.; Nogaj, B. [A. Mickiewicz University (Poland)

2006-09-15

8

Zeeman Splitting of the Nuclear Quadrupole Resonance Line of Iodine  

Microsoft Academic Search

Zeeman patterns of the nuclear Quadrupole resonance line of I127 were studied with a single crystal of iodine at medium and weak magnetic fields. The asymmetry parameter of coupling, eta, and the angle between bond axis of the iodine molecule and crystallographic c axis, \\\\varphi, were determined from the pattern at a medium magnetic field of about 120 gauss. The

Kineo Tsukada

1956-01-01

9

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

Microsoft Academic Search

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 (T1) 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

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

1980-01-01

10

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

Microsoft Academic Search

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 (Tâ) 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

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

1980-01-01

11

Nuclear quadrupole moment of the {sup 99}Tc ground state  

SciTech Connect

By combining first-principles calculations and existing nuclear magnetic resonance (NMR) experiments, we determine the quadrupole moment of the 9/2{sup +} ground state of {sup 99}Tc to be (-)0.14(3)b. This confirms the value of -0.129(20)b, which is currently believed to be the most reliable experimental determination, and disagrees with two earlier experimental values. We supply ab initio calculated electric-field gradients for Tc in YTc{sub 2} and ZrTc{sub 2}. If this calculated information would be combined with yet to be performed Tc-NMR experiments in these compounds, the error bar on the {sup 99}Tc ground state quadrupole moment could be further reduced.

Errico, Leonardo [Departamento de Fisica and Instituto de Fisica La Plata (IFLP, CCT-La Plata, CONICET-UNLP), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Casilla de Coreo 67, 1900 La Plata (Argentina); Universidad Nacional del Noroeste Bonaerense (UNNOBA), Monteagudo 2772, 2700 Pergamino (Argentina); Darriba, German; Renteria, Mario [Departamento de Fisica and Instituto de Fisica La Plata (IFLP, CCT-La Plata, CONICET-UNLP), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Casilla de Coreo 67, 1900 La Plata (Argentina); Tang Zhengning [Bayerisches Geoinstitut, Universitaet Bayreuth, DE-95440 Bayreuth (Germany); Emmerich, Heike [Computational Materials Engineering (CME), Institute for Minerals Engineering (GHI), Center for Computational Engineering Science - CCES and Juelich-Aachen Research Alliance - JARA, RWTH Aachen University, DE-52064 Aachen (Germany); Cottenier, Stefaan [Computational Materials Engineering (CME), Institute for Minerals Engineering (GHI), Center for Computational Engineering Science - CCES and Juelich-Aachen Research Alliance - JARA, RWTH Aachen University, DE-52064 Aachen (Germany) and Instituut voor Kern-en Stralingsfysica and INPAC, Katholieke Universiteit Leuven, Celestijnenlaan 200 D, BE-3001 Leuven (Belgium)

2008-05-15

12

Sensitivity of nuclear-quadrupole double-resonance detection of half-integer spin nuclei.  

PubMed

The sensitivity of the Slusher and Hahn's nuclear quadrupole double resonance technique is calculated in general for an arbitrary nuclear spin S of the quadrupole nuclei and for an arbitrary asymmetry parameter eta of the electric field gradient tensor. The nuclear spin S=5/2 ((17)O, (25)Mg, ...) is treated in details. The influence of the cross-relaxation rate between the quadrupole nuclei and the abundant spin system on the sensitivity of double resonance is discussed. The results of the theoretical analysis are applied in the analysis of the (1)H-(17)O nuclear quadrupole double resonance spectra in p-toluenesulfonamide and 2-nitrobenzoic acid. The 17O nuclear quadrupole resonance frequencies from a sulfonamide group are determined for the first time. The proton-oxygen cross-relaxation rates and the proton local frequency in zero external magnetic field are experimentally determined from the nuclear quadrupole double resonance spectra. PMID:18644741

Seliger, J; Zagar, V

2008-10-01

13

Pure Nuclear Quadrupole Spectra of Chlorine and Antimony Isotopes in Solids  

Microsoft Academic Search

Experimental measurements on nuclear quadrupole resonances of chlorine and antimony isotopes in solids have been made to an accuracy of about 0.001 percent. The results are compared in detail with theoretical results for (1) nuclear quadrupole interaction, (2) interaction between quadrupole coupling and thermal vibrations, and (3) effects of a nuclear hexadecapole. The ratio (eQq)Cl35(eQq)Cl37 varies between 1.268736 and 1.268973

Tien-Chuan Wang

1955-01-01

14

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

NASA Technical Reports Server (NTRS)

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.

Murty, A. N.

1978-01-01

15

Low-frequency nuclear quadrupole resonance with a dc SQUID  

SciTech Connect

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.

Chang, J.W.

1991-07-01

16

Nuclear magnetic and quadrupole moments for nuclear structure research on exotic nuclei  

NASA Astrophysics Data System (ADS)

One of the key issues in current nuclear physics research is to investigate the properties of so-called `exotic nuclei' and of `exotic nuclear structures'. Exotic nuclei are nuclei with a proton-to-neutron ratio that is very different from the proton-to-neutron ratio in stable nuclei (a technical term related to this ratio is the `isospin'). We define exotic nuclear structures as excitation modes of nuclei that have a very different structure than the structure (or shape) of the nuclear ground state. By putting the nucleons in a nucleus to extreme conditions of isospin and excitation energy one can investigate details of one of the four basic forces in nature: the strong force which binds the nucleons together to form a bound nucleus. While the basic properties of the strong nucleon-nucleon interaction are known from investigating the properties of nuclei near the `valley of stability', recent developments in the study of exotic nuclei have demonstrated that specific properties of the strong interaction, such as the influence of the spin-orbit term, are not yet understood. Because the nucleus forms a complex many-body system, it is impossible to describe it by ab initio calculations (except for a few very light nuclei, for which such calculations have become possible in the last few years) and therefore approximations need to be introduced. Several theoretical models have been developed in order to describe the properties of nuclei all over the nuclear chart. It is by measuring the basic nuclear properties such as masses, binding energies, lifetimes, excitation schemes, static and dynamic moments, and by comparing these properties to the predictions from the nuclear models, that these models can be tested and effective interactions can be improved. Furthermore, the measured nuclear properties can be a guide in understanding the changes, which the nuclear force undergoes in extreme conditions. In this report, we focus on the electric and magnetic properties of a nuclear state, namely on what the static magnetic dipole and electric quadrupole moments can teach us about the nucleus as a system of independently moving particles in a central potential or as a system of collectively moving nucleons. We give an overview of some techniques to measure nuclear moments for a variety of nuclear states and we discuss how the recent developments in the production of exotic nuclei have influenced the development of new experimental tools for nuclear moment studies.

Neyens, Gerda

2003-04-01

17

A NUCLEAR QUADRUPOLE RESONANCE AND X-RAY STUDY OF THE CRYSTAL STRUCTURE OF PENTACHLOROPHENOL  

Microsoft Academic Search

The crystal structure of pentachlorophenol was solved by the combined ; appiication of nuclear quadrupole resonance and x-ray diffraction. The molecules ; are linked by chains of hydrogen-bonds with a configuration similar to that in ; tetrachiorohydroquinone. The nuclear quadrupole resonance of one of the ortho ; chlorine atoms is specially affected by the intermolecular interaction. This ; interaction is

T. Sakurai

1962-01-01

18

Mixed radiation field dosimetry utilizing Nuclear Quadrupole Resonance  

SciTech Connect

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.

Hintenlang, D.

1991-01-01

19

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

NASA Astrophysics Data System (ADS)

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.

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

2006-05-01

20

The Nuclear Quadrupole Interaction of 204m Pb in Lead Oxides  

Microsoft Academic Search

The nuclear quadrupole interaction of 204mPb in lead oxides has been measured by ?–? time differential perturbed angular correlation. Ab-initio calculations of the electric field gradients and X-ray diffraction allowed the assignment of the detected nuclear quadrupole\\u000a interactions to the different Pb sites in the PbO phases litharge and massicote as well as in Pb3O4. The TDPAC probe 204mPb was

S. Friedemann; F. Heinrich; H. Haas; W. Tröger

2004-01-01

21

The angular overlap model applied to the calculation of nuclear quadrupole interactions  

Microsoft Academic Search

By the application of the angular overlap model to the calculation of nuclear quadrupole interactions (NQI), it is shown that\\u000a it is possible to predict the NQI for the111Cd nucleus in a cadmium complex with known coordination geometry. This fact makes it relevant to apply such calculations to\\u000a nuclear quadrupole interaction data for111Cd substituted zinc enzymes. It is demonstrated that

R. Bauer; S. J. Jensen; B. Schmidt-Nielsen

1988-01-01

22

Precision measurements of nuclear quadrupole moments by muonic X-rays  

Microsoft Academic Search

The electric multipole hyperfine interaction in muonic atoms is discussed. In particular, the influence of the finite size of the nuclear electric multipole-charge distribution on the values of nuclear spectroscopic multipole moments that are extracted from muonic hyperfine measurements is considered. It is shown that nuclear electric quadrupole moments can be deduced from the observed hyperfine splittings of muonic M

R. M. Steffen

1985-01-01

23

Detecting body cavity bombs with nuclear quadrupole resonance  

NASA Astrophysics Data System (ADS)

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.

Collins, Michael London

24

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

DOEpatents

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.

Fan, Non Q. (San Diego, CA); Clarke, John (Berkeley, CA)

1993-01-01

25

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

DOEpatents

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.

Fan, N.Q.; Clarke, J.

1993-10-19

26

Table of nuclear magnetic dipole and electric quadrupole moments  

Microsoft Academic Search

The table is a compilation of experimental measurements of static magnetic dipole and electric quadrupole moments of ground states and excited states of atomic nuclei throughout the periodic table. To aid identification of the states, their excitation energy, half-life, spin, and parity are given, along with a brief indication of the method and any reference standard used in the particular

N. J. Stone

2005-01-01

27

An effect of nuclear electric quadrupole moments in thermonuclear fusion plasmas  

NASA Technical Reports Server (NTRS)

Consideration of the nuclear electric quadrupole terms in the expression for the fusion Coulomb barrier suggests that this electrostatic barrier may be substantially modified from that calculated under the usual plasma assumption that the nuclei are electric monopoles. This effect is a result of the nonspherical potential shape and the spatial quantization of the nuclear spins of the fully stripped ions in the presence of a magnetic field. For monopole-quadrupole fuel cycles like p-B-11, the fusion cross-section may be substantially increased at low energies if the protons are injected at a small angle relative to the confining magnetic field.

De, B. R.; Srnka, L. J.

1978-01-01

28

Precision measurements of nuclear quadrupole moments by muonic X-rays  

Microsoft Academic Search

The electric multipole hyperfine interaction in muonic atoms is discussed. In particular, the influence of the finite size\\u000a of the nuclear electric multipole-charge distribution on the values of nuclear spectroscopic multipole moments that are extracted\\u000a from muonic hyperfine measurements is considered. It is shown that nuclear electric quadrupole moments can be deduced from\\u000a the observed hyperfine splittings of muonic M

R. M. Steffen

1985-01-01

29

Observation of nuclear quadrupole hyperfine structure in the infrared spectrum of hydrogen iodide using a tunable-diode laser  

NASA Technical Reports Server (NTRS)

Nuclear quadrupole hyperfine structure has been observed in the 1-0 vibration-rotation band of hydrogen iodide with a tunable-diode laser. The measured splittings agree well with microwave measurements of the HI molecule. Evidence for a slight change in the iodine nuclear quadrupole coupling constant from the ground to first excited vibrational state in hydrogen iodide was found.

Strow, L. L.

1980-01-01

30

Table of nuclear magnetic dipole and electric quadrupole moments  

SciTech Connect

The table is a compilation of experimental measurements of static magnetic dipole and electric quadrupole moments of ground states and excited states of atomic nuclei throughout the periodic table. To aid identification of the states, their excitation energy, half-life, spin, and parity are given, along with a brief indication of the method and any reference standard used in the particular measurement. The literature search covers the period to late 2004. Many of the entries prior to 1988 follow those in Raghavan [At. Data Nucl. Data Tables 42 (1989) 189].

Stone, N.J. [Oxford Physics, Clarendon Laboratory, Oxford OX1 3PU (United Kingdom)]. E-mail: n.stone1@physics.oxford.ac.uk

2005-05-01

31

Possibility of studying the internal field in a current-carrying conductor using nuclear quadrupole resonance  

NASA Astrophysics Data System (ADS)

A non-invasive method is proposed to probe the Landauer's residual resistivity dipoles in a current-carrying mesoscopic metal. The local voltage fluctuations induce extra local electric field gradients which can then be measured using nuclear quadrupole resonance. We have estimated that such kinds of experiments are indeed feasible.

Fu, Yaotian; Hing Sing Tang

1994-02-01

32

Lattice vibrational motion in tetracyanoquinodimethane (TCNQ): A 14N nuclear quadrupole resonance study  

Microsoft Academic Search

The mean square angular amplitudes of motion are obtained from the analysis of the 14N nuclear quadrupole resonance thermal averaging in pure TCNQ. The temperature dependence of the mean square angular amplitudes is given. The results are compared with those found at room temperature by x ray by Long et al. [Acta Cryst. 18, 932 (1965)].

Juan Murgich

1979-01-01

33

Degree of accuracy in determining the nuclear electric quadrupole moment of radium  

SciTech Connect

The multiconfiguration Dirac-Hartree-Fock (MCDHF) model has been employed to calculate the atomic expectation values responsible for the hyperfine splittings of the 7s7p {sup 3}P{sub 1,2} and {sup 1}P{sub 1} levels of radium. Calculated electric field gradients, together with the experimental electric quadrupole hyperfine structure constants, allow us to extract a nuclear electric quadrupole moment Q({sup 223}Ra) of 1.21(0.03) barn. This value is in good agreement with the semiempirical determination based on neutral radium hyperfine and fine structure, but differs from the latest result from an alkali-like radium ion.

Bieron, Jacek [Instytut Fizyki imienia Mariana Smoluchowskiego, Uniwersytet Jagiellonski, Reymonta 4, 30-059 Cracow (Poland); Pyykkoe, Pekka [Department of Chemistry, University of Helsinki, P. O. Box 55 (A.I. Virtasen aukio 1), 00014 Helsinki (Finland)

2005-03-01

34

Communication: Nuclear quadrupole moment-induced Cotton-Mouton effect in noble gas atoms  

SciTech Connect

New, high-sensitivity and high-resolution spectroscopic and imaging methods may be developed by exploiting nuclear magneto-optic effects. A first-principles electronic structure formulation of nuclear electric quadrupole moment-induced Cotton-Mouton effect (NQCME) is presented for closed-shell atoms. In NQCME, aligned quadrupole moments alter the index of refraction of the medium along with and perpendicular to the direction of nuclear alignment. The roles of basis-set convergence, electron correlation, and relativistic effects are investigated for three quadrupolar noble gas isotopes: {sup 21}Ne, {sup 83}Kr, and {sup 131}Xe. The magnitude of the resulting ellipticities is predicted to be 10{sup ?4}–10{sup ?6} rad/(M cm) for fully spin-polarized nuclei. These should be detectable in the Voigt setup. Particularly interesting is the case of {sup 131}Xe, in which a high degree of spin polarization can be achieved via spin-exchange optical hyperpolarization.

Fu, Li-juan; Vaara, Juha, E-mail: juha.vaara@iki.fi [NMR Research Group, Department of Physics, University of Oulu, P.O. Box 3000, FIN-90014 Oulu (Finland)] [NMR Research Group, Department of Physics, University of Oulu, P.O. Box 3000, FIN-90014 Oulu (Finland); Rizzo, Antonio [Istituto per i Processi Chimico-Fisici del Consiglio Nazionale delle Ricerche (IPCF-CNR), Area della Ricerca, via G. Moruzzi 1, I-56124 Pisa (Italy)] [Istituto per i Processi Chimico-Fisici del Consiglio Nazionale delle Ricerche (IPCF-CNR), Area della Ricerca, via G. Moruzzi 1, I-56124 Pisa (Italy)

2013-11-14

35

The effect of triaxially deformed nuclear charge distributions on quadrupole parameters deduced from muonic x-ray experiments  

Microsoft Academic Search

The influence of the assumed model charge density distribution in deducing nuclear quadrupole parameters from muonic X-ray experiments is investigated within the framework of the Davydov model. It is shown for the case of 192Os that the extracted quadrupole parameters are not seriously affected by a triaxial deformation of the charge distribution. The model uncertainty involved in the muonic K

Y. Tanaka; R. M. Steffen

1982-01-01

36

Coulomb disorder effects on angle-resolved photoemission and nuclear quadrupole resonance spectra in cuprates  

NASA Astrophysics Data System (ADS)

The role of Coulomb disorder, either of extrinsic origin or introduced by dopant ions in undoped and lightly doped cuprates, is studied. We demonstrate that charged surface defects in an insulator lead to a Gaussian broadening of the angle-resolved photoemisson spectroscopy (ARPES) lines. The effect is due to the long-range nature of the Coulomb interaction. A tiny surface concentration of defects about a fraction of one percent is sufficient to explain the line broadening observed in Sr2CuO2Cl2 , La2CuO4 , and Ca2CuO2Cl2 . Due to the Coulomb screening, the ARPES spectra evolve dramatically with doping, changing their shape from a broad Gaussian form to narrow Lorentzian ones. To understand the screening mechanism and the line-shape evolution in detail, we perform Hartree-Fock simulations with random positions of surface defects and dopant ions. To check validity of the model we calculate the nuclear quadrupole resonance (NQR) line shapes as a function of doping and reproduce the experimentally observed NQR spectra. Our study also indicates opening of a substantial Coulomb gap at the chemical potential. For a surface CuO2 layer the value of the gap is on the order of 10 meV while in the bulk it is reduced to the value about a few meV.

Chen, Wei; Khaliullin, Giniyat; Sushkov, Oleg P.

2009-09-01

37

Observation of H+ Ions in K2OsCl6 by Chlorine Nuclear Quadrupole Resonance  

NASA Astrophysics Data System (ADS)

Chlorine nuclear quadrupole resonance spectra of K2OsCl6 crystals containing hydrogen ions are observed at 77 and 298 K. The relative positions and intensities of the observed satellite lines indicate that the impurity ions are situated at the vacant octahedral sites in the lattice. Further, the results provide evidence for the motion of the hydrogen ions through the lattice at 298 K with a characteristic residence time of the order of 10-4 sec.

Armstrong, Robin L.; Mintz, J. David; D'Iorio, Marie

1980-03-01

38

Direct Detection of the K-Shell Perturbation Caused by the Static Nuclear Quadrupole Moment  

Microsoft Academic Search

It was found that K x rays accompanying K conversion of retarded 177-keV (predominantly M1) transitions from the 316-keV (T12=0.66 musec) nuclear state of highly deformed 169Tm have small anisotropic angular distributions with respect to the direction of gamma radiations emitted subsequent to K conversion. The result is explained as a first-order effect of the static quadrupole moment of the

S. K. Sen; D. L. Salie; E. Tomchuk

1972-01-01

39

Structural Investigation by Means of Nuclear Quadrupole Resonance III (Arsenic Tribromide)  

Microsoft Academic Search

The structure of AsBr3 is investigated by means of nuclear quadrupole resonance at about 10°C, and is compared with Braekken's results of X-ray analysis. AsBr3 has the orthorhombic symmetry, and the Br-As-Br bond angles are 99°38'± 16', 99°14'± 18' and 102°51'± 13'. The polar angles specifying the directions of the As-Br bonds with respect to the crystal axes are (62°4'±

Kenji Shimomura

1957-01-01

40

Nuclear quadrupole coupling constants in I-III-VI2 chalcopyrite semiconductors  

Microsoft Academic Search

The bond-orbital theory of covalent bonding in the ternary chalcopyrite semiconductors has been used to interpret published values for the nuclear quadrupole coupling constants in a number of I-III-VI2 materials. Calculations are performed for 63Cu, 27Al, and 69Ga cations taking account both of lattice and local orbital contributions to electric-field gradients. The theory is shown to be quantitative when applied

M. E. Lines

1978-01-01

41

Nuclear quadrupole resonance spectra of drawing-induced crystallization in As 2Se 3 fibers  

Microsoft Academic Search

Pulsed 75As nuclear quadrupole resonance (NQR) experiments performed on fibers of As2Se3 drawn at various rates (> 100 m\\/min) reveal structural changes from the bulk, well-annealed glass. In addition to the presence of As?As bonds in the nominally stoichiometric fibers, a distorted crystalline phase (< 10% by volume) occurs at the largest draw rates. Because they are highly distorted, these

P. Hari; P. C. Taylor; W. A. King; W. C. LaCourse

1997-01-01

42

Nuclear quadrupole resonances in compact vapor cells: the crossover from the NMR to the NQR interaction regimes  

E-print Network

We present the first experimental study that maps the transformation of nuclear quadrupole resonances from the pure nuclear quadrupole regime to the quadrupole-perturbed Zeeman regime. The transformation presents an interesting quantum-mechanical problem, since the quantization axis changes from being aligned along the axis of the electric-field gradient tensor to being aligned along the magnetic field. We achieve large nuclear quadrupole shifts for I = 3/2 131-Xe by using a 1 mm^3 cubic cell with walls of different materials. When the magnetic and quadrupolar interactions are of comparable size, perturbation theory is not suitable for calculating the transition energies. Rather than use perturbation theory, we compare our data to theoretical calculations using a Liouvillian approach and find excellent agreement.

E. A. Donley; J. L. Long; T. C. Liebisch; E. R. Hodby; T. A. Fisher; J. Kitching

2008-12-10

43

First Principles Study of Nuclear Quadrupole Interactions in Single and Double Chain DNA and Solid Nucleobases  

NASA Astrophysics Data System (ADS)

Nuclear Quadrupole Interactions (NQI) of ^17O, ^14N and ^2H nuclei have been studied for free nucleobases and nucleobases in single strand and double strand DNA and in solid state. Our first-principles investigations were carried out using the Gaussian 2003 set of programs to implement the Hartree-Fock procedure combined with many-body effects included using many-body perturbation theory. As expected for NQI in general, many-body effects are found to be small. Results will be presented for the quadrupole coupling constants (e^2qQ) and asymmetry parameters (?) for the nucleobases in the various environments. Trends in e^2qQ and ? in the different environments will be discussed. In the case of the solid nucleobases, comparisons will be made with available experimental data [1] for ^17O nuclei.[3pt] [1] Gang Wu et al., J. Am. Chem. Soc. 124, 1768 (2002)

Das, T. P.; Pink, R. H.; Badu, S. R.; Dubey, Archana; Scheicher, R. H.; Saha, H. P.; Chow, Lee; Huang, M. B.

2009-03-01

44

Nuclear Quadrupole Interaction at 187W(?-)187Re in Tungsten Compounds  

NASA Astrophysics Data System (ADS)

The nuclear quadrupole interaction at 187W(?-)187 Re was determined by time differential perturbed angular correlation in WC, WS2, WSe2, WSi2, and CaWO4 to be (at 300 K): vQ = 335.9(2), 1094.9(1), 10311), 1131,5( 1), and 1085.9( 1) MHz, respectively. The asymmetry parameter ?was zero in all cases. For WSe2 and CaWO4 the temperature dependence of the nculear quadrupole interaction was determined between 300 K and about 900 K. Ab initio calculations of electric field gradients, using the WIEN95-code, were carried out for WC, WS2, WSe2, and WSi2 at W-sites and Re-impurities, and for CaWO4 at W-sites. Good agreement with experimental data was found.

Schmidt, Pit; Soldner, Torsten; Tröger, Wolfgang; Ni, Xinbo; Butz, Tilman; Blaha, Peter

1998-07-01

45

Quadrupole moments and nuclear shapes of neutron-deficient gold isotopes  

NASA Astrophysics Data System (ADS)

The hyperfine structure splitting and the isotope shift of the neutron-deficient gold isotopes 194-191Au in the optical transition 5 d9 6 s22D{3}/{2} ? 5 d10 6 p2P{1}/{2} (627.8 nm) have been determined by collinear laser spectroscopy at the on-line isotope separator ISOLDE. The nuclear magnetic moments, spectroscopic quadrupole moments and changes in the mean square charge radii are deduced. Experimental electromagnetic moments and deformation parameters are compared with results of a particle-triaxial-rotor model calculation for both odd- A and odd-odd gold nuclei. Very good overall agreement between calculation and experimental data has been achieved. We find, for the first time, consistent evidence for a relatively large contribution from hexadecapole deformation ( ?4 = 0.06, ?4 = -0.05) to odd- A gold isotopes ground states in the region of 183 ? A ? 197. Calculated values of quadrupole deformation are consistent with the prolate-to-oblate shape change between ground states of 186Au and 187Au. In addition, our results suggest another shape change between 190Au (oblate) and 191Au (triaxial). The former change is accompanied by a considerable change in quadrupole deformation, the latter occurs at almost constant deformation.

Passler, G.; Rikovska, J.; Arnold, E.; Kluge, H.-J.; Monz, L.; Neugart, R.; Ravn, H.; Wendt, K.; Isolde Collaboration

1994-11-01

46

Precision magnetic quadrupole lens for a nuclear scanning microprobe based on an ÉGP-10 electrostatic tandem accelerator  

Microsoft Academic Search

Basic ideas underlying the design of a precision magnetic quadrupole lens for a nuclear scanning microprobe with a maximal\\u000a accelerating voltage of 14 MV are set forth. Four magnetic quadrupoles are combined into doublets. The doublets are placed\\u000a on adjusting gears, which bring the local coordinate system of each lens into coincidence with the laboratory system related\\u000a to the axis

V. A. Rebrov; A. G. Ponomarev; D. V. Magilin; I. A. Beloshapka; A. B. Dudnik; S. N. Abramovich; N. V. Zavjalov; A. G. Zvenigorodsky; E. V. Zimin

2007-01-01

47

Microwave Spectrum, Molecular Structure, and Bromine Nuclear Quadrupole Coupling Tensor of Bromodiborane  

Microsoft Academic Search

The rotational spectra of eight isotopic species of bromodiborane (11B2H579Br, 11B2H581Br, 10B2H579Br, 10B2H581Br, 10B11BH581Br, 11B10BH581Br, 11B2D579Br, and 11B2D581Br) were studied in the region 10–27 GHz, and analyzed to obtain values for the rotational constants and the complete bromine nuclear quadrupole coupling tensor. Structural parameters found by isotopic substitution are B&sngbnd;B = 1.773 ± 0.003 Å, B&sngbnd;Br = 1.930 ± 0.005

Arthur C. Ferguson; C. D. Cornwell

1970-01-01

48

X-Ray Diffraction and Nuclear Quadrupole Resonance Studies of Chromium Trichloride  

Microsoft Academic Search

The infinite-layer compound CrCl3 is found to undergo a first-order phase transformation near 240°K. The crystal structures of the high- and low-temperature phases have been elucidated by detailed x-ray diffraction and 35Cl nuclear quadrupole resonance studies. The previously reported structure for CrCl3 is shown to be incorrect. The present single-crystal diffraction results at 298° and 225°K give monoclinic (C2\\/m: a0=5.959

Bruno Morosin; Albert Narath

1964-01-01

49

Investigation of Wavelet-Based Enhancements to Nuclear Quadrupole Resonance Explosives Detectors  

SciTech Connect

Nuclear Quadrupole Resonance (NQR) is effective for the detection and identification of certain types of explosives such as RDX, PETN and TNT. In explosive detection, the NQR response of certain 14N nuclei present in the crystalline material is probed. The 14N nuclei possess a nuclear quadrupole moment which in the presence of an electric field gradient produces an energy level splitting which may be excited by radio-frequency magnetic fields. Pulsing on the sample with a radio signal of the appropriate frequency produces a transient NQR response which may then be detected. Since the resonant frequency is dependent upon both the quadrupole moment of the 14N nucleus and the nature of the local electric field gradients, it is very compound specific. Under DARPA sponsorship, the authors are using multiresolution methods to investigate the enhancement of operation of NQR explosives detectors used for land mine detection. For this application, NQR processing time must be reduced to less than one second. False alarm responses due to acoustic and piezoelectric ringing must be suppressed. Also, as TNT is the most prevalent explosive found in land mines, NQR detection of TNT must be made practical despite unfavorable relaxation tunes. All three issues require improvement in signal-to-noise ratio, and all would benefit from improved feature extraction. This paper reports some of the insights provided by multiresolution methods that can be used to obtain these improvements. It includes results of multiresolution analysis of experimentally observed NQR signatures for RDX responses and various false alarm signatures in the absence of explosive compounds.

Kercel, Stephen W.; Dress, William B.; Hibbs, Andrew D.; Barrall, Geoffrey A.

1998-06-01

50

Hartree-Fock Cluster Study of Electronic Structures and Nuclear Quadrupole Interactions in Solid Nucleobases.  

NASA Astrophysics Data System (ADS)

In recent work [1] we have studied nucleobases attached to a CH3 group to simulate the influence of their binding to the sugar rings and the phosphate groups in DNA and RNA and the effect of this binding on the nuclear quadrupole interactions of ^14N, ^17O and ^2H nuclei. Our results from this work have indicated that for ^17O, the binding to the CH3 group moves our results from the free nucleobases closer to the experimentally observed data [2] in the solid nucleobases. We are now investigating the solid nucleobases by the first --principles Hartree-Fock cluster procedure that we have employed earlier for the halogen molecular solids [3]. Our results for the binding energy of an imidazole molecule in the molecular solid system and the ^14N, ^17O and ^2H nuclear quadrupole interaction parameters will be presented. [1] T.P. Das et al (at this APS meeting), [2] Gang Wu et al, J. Am.Chem. Soc. 124, 1768(2002). [3] M.M. Aryal et al Hyperfine Interactions (to be published).

Scheicher, R. H.; Dubey, Archana; Badu, S. R.; Saha, H. P.; Pink, R. H.; Nagamine, K.; Torikai, E.; Chow, Lee; Das, T. P.

2008-03-01

51

Theory of electronic structures and nuclear quadrupole interactions in molecular solids and semiconductor surfaces  

NASA Astrophysics Data System (ADS)

We have investigated, using the Hartree-Fock Roothaan variational procedure, the electronic structures and associated nuclear quadrupole interactions (NQI) for the molecular solids, RDX (C3H6N6O6),/ /beta- HMX(C4H8N8O8), Cocaine (C17H21NO4), Cocaine Hydrochloride (C17H21NO4HCl) and Heroin (C21H23NO5) and for the (111) surface of silicon with adsorbed radioactive 111In atom and negative cadmium ion containing the excited nucleus 111Cd/* resulting from electron capture by lllIn. Our investigations indicate that for the ring 14N NQI parameters in RDX and ?-HMX there is very good agreement between theory and experiment. For the peripheral 14N nuclei in NO2 groups, while the calculated electronic structures do explain the much weaker quadrupole coupling constants for these nuclei relative to the ring 14N nuclei, there are significant differences between theory and experiment. The influence of intermolecular interactions between adjacent molecules in the solid is invoked as a possible source for these differences. For the controlled substances, Cocaine and Heroin, again very good agreement is obtained between theory and experiment. For Cocaine Hydrochloride theory is able to explain the much smaller observed 14N nuclear quadrupole resonance frequency as compared to pure Cocaine. However there are significant differences between theory and experiment for the 14N and 35Cl quadrupole resonance frequencies. The influence of intermolecular interactions is one of the factors suggested to explain the difference. For the silicon (111) surface, the observed 111Cd/* NQI parameters, with the cadmium nucleus assumed to be located at the same site as the 111In nucleus from which it is generated, can be successfully explained by theory with the indium atom located at the two distinct sites available with the DAS model for the 7 x 7 reconstructed (111) surface. Some quantitative differences still remain, one of the main factor suggested for their explanation being a need for a thorough analysis of relaxation effects in the positions of silicon atoms associated with the presence of the indium atom. Applications of the Hartree-Fock Cluster theory to other related systems is suggested to subject the DAS model to additional tests at the microscopic level as in the system studied in the present thesis. (Abstract shortened by UMI.)

Pati, Ranjit

52

Time-Reversal Symmetry Violation in Molecules Induced by Nuclear Magnetic Quadrupole Moments  

NASA Astrophysics Data System (ADS)

Recent measurements in paramagnetic molecules improved the limit on the electron electric dipole moment (EDM) by an order of magnitude. Time-reversal (T) and parity (P) symmetry violation in molecules may also come from their nuclei. We point out that nuclear T, P-odd effects are amplified in paramagnetic molecules containing deformed nuclei, where the primary effects arise from the T, P-odd nuclear magnetic quadrupole moment (MQM). We perform calculations of T, P-odd effects in the molecules TaN, ThO, ThF+, HfF+, YbF, HgF, and BaF induced by MQMs. We compare our results with those for the diamagnetic TlF molecule, where the T, P-odd effects are produced by the nuclear Schiff moment. We argue that measurements in molecules with MQMs may provide improved limits on the strength of T, P-odd nuclear forces, on the proton, neutron, and quark EDMs, on quark chromo-EDMs, and on the QCD ? term and CP-violating quark interactions.

Flambaum, V. V.; DeMille, D.; Kozlov, M. G.

2014-09-01

53

Time-reversal symmetry violation in molecules induced by nuclear magnetic quadrupole moments.  

PubMed

Recent measurements in paramagnetic molecules improved the limit on the electron electric dipole moment (EDM) by an order of magnitude. Time-reversal (T) and parity (P) symmetry violation in molecules may also come from their nuclei. We point out that nuclear T, P-odd effects are amplified in paramagnetic molecules containing deformed nuclei, where the primary effects arise from the T, P-odd nuclear magnetic quadrupole moment (MQM). We perform calculations of T, P-odd effects in the molecules TaN, ThO, ThF+, HfF+, YbF, HgF, and BaF induced by MQMs. We compare our results with those for the diamagnetic TlF molecule, where the T, P-odd effects are produced by the nuclear Schiff moment. We argue that measurements in molecules with MQMs may provide improved limits on the strength of T, P-odd nuclear forces, on the proton, neutron, and quark EDMs, on quark chromo-EDMs, and on the QCD ? term and CP-violating quark interactions. PMID:25238355

Flambaum, V V; DeMille, D; Kozlov, M G

2014-09-01

54

Time-reversal symmetry violation in molecules induced by nuclear magnetic quadrupole moments  

E-print Network

Recent measurements in paramagnetic molecules improved the limit on the electron electric dipole moment (EDM) by an order of magnitude. Time-reversal (T) and parity (P) symmetry violation in molecules may also come from their nuclei. We point out that nuclear T,P-odd effects are amplified in paramagnetic molecules containing deformed nuclei, where the primary effects arise from the T,P-odd nuclear magnetic quadrupole moment (MQM). We perform calculations of T,P-odd effects in the molecules TaN, ThO, ThF$^+$, HfF$^+$, YbF, HgF, and BaF induced by MQMs. We compare our results with those for the diamagnetic TlF molecule, where the T,P-odd effects are produced by the nuclear Schiff moment. We argue that measurements in molecules with MQMs may provide improved limits on the strength of T,P-odd nuclear forces, on the proton, neutron and quark EDMs, on quark chromo-EDMs, and on the QCD $\\theta$-term and CP-violating quark interactions.

V. V. Flambaum; D. DeMille; M. G. Kozlov

2014-08-25

55

14N nuclear quadrupole resonance and proton spin–lattice relaxation study of phase transition in pyridazine perchlorate  

Microsoft Academic Search

The temperature dependence of the 14N nuclear quadrupole resonance frequencies in pyridazine perchlorate has been measured by double resonance. The results show that in the low temperature phase the pyridazinium ions are static, while in the high temperature phase the ions reorient around the normal to the plane of the ring between six equivalent orientations in agreement with the X-ray

J. Seliger; V. Žagar; T. Asaji

2009-01-01

56

Determination of the Nuclear Quadrupole Moment of Fe57 m from alpha-Fe2O3 Data  

Microsoft Academic Search

A new value for the nuclear quadrupole moment Q (Fe57m) of the 14.4-keV level of Fe57 based on alpha-Fe2O3 data has been determined from a detailed series of Mössbauer-effect quadrupole-interaction measurements, x-ray structure-parameter studies, and lattice-sum calculations (including dipole moments). At room temperature, e2qQ=+0.880+\\/-0.024 mm\\/sec. This, when combined with the principal component of the electric field gradient tensor at the

J. O. Artman; A. H. Muir; H. Wiedersich

1968-01-01

57

Nuclear quadrupole moment-induced Cotton-Mouton effect in molecules  

SciTech Connect

Nuclear magneto-optic effects could make important contributions to novel, high-sensitivity, and high-resolution spectroscopic and imaging methods that provide nuclear site-specific structural and dynamic information on molecular and materials systems. Here we present a first-principles electronic structure formulation of nuclear quadrupole moment-induced Cotton-Mouton effect in terms of response theory, as well as ab initio and density-functional theory calculations of this phenomenon for a series of molecular liquids: H{sub 2}O, CH{sub 3}NO{sub 2}, CH{sub 3}CH{sub 2}OH, C{sub 6}H{sub 6}, C{sub 6}H{sub 12} (cyclohexane), HI, XeF{sub 2}, WF{sub 5}Cl, and Pt(C{sub 2}dtp){sub 2}. The roles of basis-set convergence, electron correlation, and relativistic effects are discussed. The estimated order of magnitude of the overall ellipticities induced to linearly polarized light is 10{sup ?3}–10{sup ?7} rad/(M cm) for fully spin polarized nuclei. The cases with the largest presently obtained ellipticities should be detectable with modern instrumentation in the Voigt magneto-optic setup, particularly for the heavy nuclei.

Fu, Li-juan, E-mail: lijuan.fu@oulu.fi, E-mail: juha.vaara@iki.fi; Vaara, Juha, E-mail: lijuan.fu@oulu.fi, E-mail: juha.vaara@iki.fi [NMR Research Group, Department of Physics, University of Oulu, P.O. Box 3000, FIN-90014 Oulu (Finland)] [NMR Research Group, Department of Physics, University of Oulu, P.O. Box 3000, FIN-90014 Oulu (Finland)

2014-01-14

58

Nuclear quadrupole moment-induced Cotton-Mouton effect in molecules.  

PubMed

Nuclear magneto-optic effects could make important contributions to novel, high-sensitivity, and high-resolution spectroscopic and imaging methods that provide nuclear site-specific structural and dynamic information on molecular and materials systems. Here we present a first-principles electronic structure formulation of nuclear quadrupole moment-induced Cotton-Mouton effect in terms of response theory, as well as ab initio and density-functional theory calculations of this phenomenon for a series of molecular liquids: H2O, CH3NO2, CH3CH2OH, C6H6, C6H12 (cyclohexane), HI, XeF2, WF5Cl, and Pt(C2dtp)2. The roles of basis-set convergence, electron correlation, and relativistic effects are discussed. The estimated order of magnitude of the overall ellipticities induced to linearly polarized light is 10(-3)-10(-7) rad/(M cm) for fully spin polarized nuclei. The cases with the largest presently obtained ellipticities should be detectable with modern instrumentation in the Voigt magneto-optic setup, particularly for the heavy nuclei. PMID:24437861

Fu, Li-juan; Vaara, Juha

2014-01-14

59

Nuclear quadrupole moment-induced Cotton-Mouton effect in molecules  

NASA Astrophysics Data System (ADS)

Nuclear magneto-optic effects could make important contributions to novel, high-sensitivity, and high-resolution spectroscopic and imaging methods that provide nuclear site-specific structural and dynamic information on molecular and materials systems. Here we present a first-principles electronic structure formulation of nuclear quadrupole moment-induced Cotton-Mouton effect in terms of response theory, as well as ab initio and density-functional theory calculations of this phenomenon for a series of molecular liquids: H2O, CH3NO2, CH3CH2OH, C6H6, C6H12 (cyclohexane), HI, XeF2, WF5Cl, and Pt(C2dtp)2. The roles of basis-set convergence, electron correlation, and relativistic effects are discussed. The estimated order of magnitude of the overall ellipticities induced to linearly polarized light is 10-3-10-7 rad/(M cm) for fully spin polarized nuclei. The cases with the largest presently obtained ellipticities should be detectable with modern instrumentation in the Voigt magneto-optic setup, particularly for the heavy nuclei.

Fu, Li-juan; Vaara, Juha

2014-01-01

60

Giant Quadrupole Resonances in 208Pb, the nuclear symmetry energy and the neutron skin thickness  

E-print Network

Recent improvements in the experimental determination of properties of the Isovector Giant Quadrupole Resonance (IVGQR), as demonstrated in the A=208 mass region, may be instrumental for characterizing the isovector channel of the effective nuclear interaction. We analyze properties of the IVGQR in 208Pb, using both macroscopic and microscopic approaches. The microscopic method is based on families of non-relativistic and covariant Energy Density Functionals (EDF), characterized by a systematic variation of isoscalar and isovector properties of the corresponding nuclear matter equations of state. The macroscopic approach yields an explicit dependence of the nuclear symmetry energy at some subsaturation density, for instance S(\\rho=0.1 fm^{-3}), or the neutron skin thickness \\Delta r_{np} of a heavy nucleus, on the excitation energies of isoscalar and isovector GQRs. Using available data it is found that S(\\rho=0.1 fm{}^{-3})=23.3 +/- 0.6 MeV. Results obtained with the microscopic framework confirm the correlation of the \\Delta r_{np} to the isoscalar and isovector GQR energies, as predicted by the macroscopic model. By exploiting this correlation together with the experimental values for the isoscalar and isovector GQR energies, we estimate \\Delta r_{np} = 0.14 +/- 0.03 fm for 208Pb, and the slope parameter of the symmetry energy: L = 37 +/- 18 MeV.

X. Roca-Maza; M. Brenna; B. K. Agrawal; P. F. Bortignon; G. Colò; Li-Gang Cao; N. Paar; D. Vretenar

2013-03-05

61

Analysis of nuclear-quadrupole-resonance spectrum of incommensurate phases: The case of bis(4-chlorophenyl) sulfone  

Microsoft Academic Search

In this work, previous experimental studies of the 35Cl nuclear-quadrupole-resonance (NQR) line shape in the incommensurate phase of bis(4-chlorophenyl) sulfone were extended. The broad spectra in the incommensurate phase (IC) were measured using the Fourier transform of the nuclear signal to avoid systematic errors committed in some studies of this compound. The results were interpreted within the framework of the

J. Schneider; C. Schürrer; A. Wolfenson; A. Brunetti

1998-01-01

62

Understanding the nuclear structure of heavy elements  

NASA Astrophysics Data System (ADS)

The study of heavy and superheavy elements has always been one of the cornerstones of nuclear physics studies. These studies are driven by a desire to create new elements and to determine the limits of nuclear stability. Current experiments to synthesize new elements aim at the fabled ‘Island of Stability’ which should be found in the region of the next ‘magic’ numbers for protons and neutrons beyond Z = 82 and N = 126 (208Pb). The island is predicted to be around proton number 114-126 and neutron number 184. In recent years, another approach to understanding heavy nuclear systems has gained momentum, whereby nuclei with a much lower proton number of around 100 are studied in detail. The motivation for and results of such studies will be presented.

Greenlees, P. T.

2013-01-01

63

C P -Violating Effect of the Th Nuclear Magnetic Quadrupole Moment: Accurate Many-Body Study of ThO  

NASA Astrophysics Data System (ADS)

Investigations of C P violation in the hadron sector may be done using measurements in the ThO molecule. Recent measurements in this molecule improved the limit on the electron electric dipole moment (EDM) by an order of magnitude. Another time-reversal (T ) and parity (P )-violating effect in 229ThO is induced by the nuclear magnetic quadrupole moment. We perform nuclear and molecular calculations to express this effect in terms of the strength constants of T , P -odd nuclear forces, neutron EDM, QCD vacuum angle ? , quark EDM, and chromo-EDM.

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

2014-12-01

64

CP-violating effect of the Th nuclear magnetic quadrupole moment: accurate many-body study of ThO.  

PubMed

Investigations of CP violation in the hadron sector may be done using measurements in the ThO molecule. Recent measurements in this molecule improved the limit on the electron electric dipole moment (EDM) by an order of magnitude. Another time-reversal (T) and parity (P)-violating effect in 229ThO is induced by the nuclear magnetic quadrupole moment. We perform nuclear and molecular calculations to express this effect in terms of the strength constants of T, P-odd nuclear forces, neutron EDM, QCD vacuum angle ?, quark EDM, and chromo-EDM. PMID:25615324

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

2014-12-31

65

Nuclear quadrupole resonance and x-ray investigation of the structure of Na2\\/3CoO2  

Microsoft Academic Search

We have synthesized various samples of the x=2\\/3 phase of sodium cobaltate NaxCoO2 and performed x-ray powder diffractions spectra to compare the diffraction with the structure proposed previously from NMR and nuclear quadrupole resonance (NQR) experiments [H. Alloul, I. R. Mukhamedshin, T. A. Platova, and A. V. Dooglav, EPL 85, 47006 (2009)]. Rietveld analyses of the data are found in

T. A. Platova; I. R. Mukhamedshin; H. Alloul; A. V. Dooglav; G. Collin

2009-01-01

66

Zeeman Study on Nuclear Quadrupole Resonances in AsI3 and AsI3\\\\cdot3S8  

Microsoft Academic Search

Principal axis systems and asymmetry parameter of the electric field gradient tensors were determined by studying Zeeman effect of nuclear quadrupole resonances of As75 and I127. The iodine resonance in AsI3 showed that there are three principal axis system swhose z axes form a trigonal pyramid having an apex angle of 91.7°± 2.5°. The fact that this angle did not

Yoshihito Abe

1958-01-01

67

a Microwave Spectroscopic Study of Methylated Indoles: Internal Rotation and Nuclear Quadrupole Coupling  

NASA Astrophysics Data System (ADS)

The barrier to methyl internal rotation of an asymmetric two ring system depends on the position of the methyl substitution. A cavity based Fourier transform microwave spectrometer was used to record rotational spectra of different methyl substituted indoles in the range of 10.5 - 20 GHz. About 160 hyperfine components arising from about 30 rotational transitions were assigned for each 1- and 3-methylindole. The program XIAMa was used to fit the rotational constants, distortion constants, nuclear quadrupole coupling constants and barrier to internal rotation to the measured transition frequencies of the A and E internal rotation states. The best fit values for the rotational constants are A = 2651.12(2) MHz, B = 1305.266(2) MHz, C = 879.800(2) MHz for 1-methylindole and A = 2603.7224(5) MHz, B = 1268.7886(1) MHz, C = 857.8091(1) MHz for 3-methylindole. The different values observed for the barrier to internal rotation, 279.8(3) wn for 1-methylindole and 433(1) wn for 3-methylindole, may be due to the different rotor axis lengths and differences in local ?-electron density. Progress on the assignment of additional methylated indoles will also be presented. aH. Hartwig and H. Dreizler, Z. Naturforsch, 51a, 923 - 932.

Gurusinghe, Ranil; Tubergen, Michael

2014-06-01

68

Noise-resilient multi-frequency surface sensor for nuclear quadrupole resonance  

NASA Astrophysics Data System (ADS)

A planar nuclear quadrupole resonance (NQR) sensor has been developed. The sensor is resilient to environmental noise and is capable of simultaneous independent multi-frequency operation. The device was constructed as an open multimodal birdcage structure, in which the higher modes, generally not used in magnetic resonance, are utilized for NQR detection. These modes have smooth distributions of the amplitudes of the corresponding radiofrequency magnetic fields everywhere along the sensor's surface. The phases of the fields, on the other hand, are cyclically shifted across the sensor's surface. Noise signals coming from distant sources, therefore, induce equal-magnitude cyclically phase-shifted currents in different parts of the sensor. When such cyclically phase-shifted currents arrive at the mode connection point, they destructively interfere with each other and are cancelled out. NQR signals of polycrystalline or disordered substances, however, are efficiently detected by these modes because they are insensitive to the phases of the excitation/detection. No blind spots exist along the sensor's surface. The sensor can be used for simultaneous detection of one or more substances in locations with environmental noise.

Peshkovsky, A. S.; Cattena, C. J.; Cerioni, L. M.; Osán, T. M.; Forguez, J. G.; Peresson, W. J.; Pusiol, D. J.

2008-10-01

69

Narcotics and explosives detection by 14N pure nuclear quadrupole resonance  

NASA Astrophysics Data System (ADS)

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 proof-of-concept NQR explosives detector which interrogates a volume of 300 liters (10 ft3). With minimal modification to the existing explosives detector, we can detect operationally relevant quantities of (free base) cocaine within the 300-liter inspection volume in 6 seconds. We are presently extending this approach to the detection of heroin base and also examining 14N and 35,37Cl pure NQR for detection of the hydrochloride forms of both materials. An adaptation of this NQR approach may be suitable for scanning personnel for externally carried contraband and explosives. We first outline the basics of the NQR approach, highlighting strengths and weaknesses, and then present representative results for RDX and cocaine detection. We also present a partial compendium of relevant NQR parameters measured for some materials of interest.

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

1994-03-01

70

Low-power stimulated emission nuclear quadrupole resonance detection system utilizing Rabi transitions  

NASA Astrophysics Data System (ADS)

The application of CW radar techniques to Nuclear Quadrupole Resonance (NQR) detection of nitrogen based explosives and chlorine based narcotics enables the use of low power levels, in the range of 10's of watts, to yield high signal strengths. By utilizing Rabi transitions the nucleus oscillates between states one and two under the time dependent incident electromagnetic field and alternately absorbs energy from the incident field while emitting coherent energy via stimulated emission. Through the application of a cancellation algorithm the incident field is eliminated from the NQR response, allowing the receive signal to be measured while transmitting. The response signal is processed using matched filters of the NQR response which enables the direct detection of explosives. This technology has applicability to the direct detection of explosives and narcotics for security screening, all at safe low power levels, opposed to the current XRay and Millimeter wave screening systems that detect objects that may contain explosives and utilize high power. The quantum mechanics theoretical basis for the approach and an application for a system for security screening are described with empirical results presented to show the effects observed.

Apostolos, John; Mouyos, William; Feng, Judy; Chase, Walter

2013-06-01

71

Precision magnetic quadrupole lens for a nuclear scanning microprobe based on an ÉGP-10 electrostatic tandem accelerator  

NASA Astrophysics Data System (ADS)

Basic ideas underlying the design of a precision magnetic quadrupole lens for a nuclear scanning microprobe with a maximal accelerating voltage of 14 MV are set forth. Four magnetic quadrupoles are combined into doublets. The doublets are placed on adjusting gears, which bring the local coordinate system of each lens into coincidence with the laboratory system related to the axis of the beam. Each lens provides a maximal gradient of the field of 0.68 T/cm, which makes it possible to perform stigmatic focusing of the beam with a working distance of 22 cm. All lenses are nonseparable and made of one piece of high-quality electrical steel. A special lens-feeding unit is designed that provides manual and remote control of pole tip excitation.

Rebrov, V. A.; Ponomarev, A. G.; Magilin, D. V.; Beloshapka, I. A.; Dudnik, A. B.; Abramovich, S. N.; Zavjalov, N. V.; Zvenigorodsky, A. G.; Zimin, E. V.

2007-03-01

72

Nuclear quadrupole alignment of 176Lum and 177Lu in a lutetium single crystal at low temperatures and systematics of electric field gradients in pure hexagonal transition metals  

Microsoft Academic Search

The quadrupole frequencies for 176Lum and 177Lu nuclei in a Lu single crystal have been determined by nuclear orientation at temperatures down to 6 mK as -128(16) MHz and +294(37) MHz, respectively. From the observed gamma anisotropies several gamma-ray multipole mixing ratios could be derived. With the known ground-state quadrupole moment of Q=3.39(2) b for 177Lu the electric field gradient

H. Ernst; E. Hagn; E. Zech; G. Eska

1979-01-01

73

Nuclear quadrupole coupling parameters and structural nature of the nonlinear optical material Li2B4O7 by NMR.  

PubMed

The structural nature underlying the nonlinear optical (NLO) properties of Li2B4O7 is characterized by nuclear magnetic resonance (NMR). The rotation patterns of (11)B NMR were measured. We observed sixteen different spectra which were divided into two groups, corresponding to two types of boron atoms, 4-coordinated B(1) and 3-coordinated B(2), which have different boron-oxygen rings and lie at chemically inequivalent sites. From these results, the quadrupole parameter and the principal axis of the electric field gradient (EFG) tensor were determined for the two borons. PMID:25618744

Lim, Ae Ran; Kim, In Gyoo

2015-01-01

74

Nuclear Charge Radii and Electric Quadrupole Moments of Even-Even Isotopes  

Microsoft Academic Search

Isotope shifts of the charge mean-square radii and electric quadrupole moments of even-even nuclei with 20 ? Z ? 98 are calculated using a dynamical microscopic model. A single-particle Nilsson potential with the Seo set of correction terms, pairing forces in the BCS formalism, and a long-range interaction in the local approximation are used. A collective Hamiltonian is obtained using

B. Nerlo-Pomorska; B. Mach

1995-01-01

75

Nuclear quadrupole deformation effects on pionic and kaonic X-rays  

Microsoft Academic Search

X-rays from pionic and kaonic In, Ho and Ta and from pionic Bi have been measured in order to determine quadrupole moments from the hyperfine splitting. The strong interaction monopole shifts ?0 and widths Gamma0 have been deduced and compared with predictions of a deformed optical-model calculation. Data have been obtained for the pionic 3d levels in In, Ho, 168Er,

C. J. Batty; S. F. Biagi; R. A. J. Riddle; B. L. Roberts; G. J. Pyle; G. T. A. Squier; D. M. Asbury; A. S. Clough

1981-01-01

76

Toward understanding the effects of nuclear war  

SciTech Connect

The authors discuss the scientific justifications for studying the consequences of nuclear war. The consequences of nuclear war and nuclear winter - biotic impoverishment, climate change, pollution of the air, water, and soil - recapitulate in compressed time the patterns of ecological change humankind is even now imposing on the planet. By studying the biological consequences of nuclear war, important discoveries about the intricate nature of the global ecosystem may be made. Wiser management practices and more thorough appreciation of alterations in the physical and biological environment could results.

Grover, H.D.; White, G.F.

1985-10-01

77

Nuclear energy and sustainability: Understanding ITER  

Microsoft Academic Search

Deregulation and new environmental requirements combined with the growing scarcity of fossil resources and the increasing world energy demand lead to a renewal of the debate on tomorrow's energies. Specifically, nuclear energy, which has undeniable assets, faces new constraints. On the one hand, nuclear energy is very competitive and harmless to greenhouse effect. From this point, it seems to be

Karine Fiore

2006-01-01

78

Understanding and managing corrosion in nuclear power plants  

Microsoft Academic Search

The main theme of this paper is a concept: understanding and managing corrosion in nuclear power plants. The concept is not new--in various forms the concept has been applied throughout the development and maturing of nuclear technology. However, the concept has frequently not been well conceived and applied. Too often, understanding corrosion has been based on reaction rather than on

A. B. Jr. Johnson; D. B. Jarrell; U. P. Sinha; V. N. Shah

1991-01-01

79

Non-yrast nuclear spectra in a model of coherent quadrupole-octupole motion  

E-print Network

A model assuming coherent quadrupole-octupole vibrations and rotations is applied to describe non-yrast energy sequences with alternating parity in several even-even nuclei from different regions, namely $^{152,154}$Sm, $^{154,156,158}$Gd, $^{236}$U and $^{100}$Mo. Within the model scheme the yrast alternating-parity band is composed by the members of the ground-state band and the lowest negative-parity levels with odd angular momenta. The non-yrast alternating-parity sequences unite levels of $\\beta$-bands with higher negative-parity levels. The model description reproduces the structure of the considered alternating-parity spectra together with the observed B(E1), B(E2) and B(E3) transition probabilities within and between the different level-sequences. B(E1) and B(E3) reduced probabilities for transitions connecting states with opposite parity in the non-yrast alternating-parity bands are predicted. The implemented study outlines the limits of the considered band-coupling scheme and provides estimations about the collective energy potential which governs the quadrupole-octupole properties of the considered nuclei.

N. Minkov; S. Drenska; M. Strecker; W. Scheid; H. Lenske

2012-03-08

80

THE DETERMINATION OF THE NUCLEAR QUADRUPOLE MOMENTS OF THE 247-kev LEVEL OF CADMIUM111 BY MEASUREMENT OF THE CIRCULAR POLARIZATION OF $gamma$ RADIATION  

Microsoft Academic Search

The interaction of the nuclear electric quadrupole moment with an ; electric field gradient at the position of the nucleus changes the angular ; correlation of two successive gamma rays and also produces a circular ; polarization of the gamma rays. By measuring this polarization it is possible ; to distinguish between electric and magnetic attenuation of the gamma cascade.

H.-J. Behrend; D. Budnick

1962-01-01

81

Using nitrogen-14 nuclear quadrupole resonance and electric field gradient information for the study of radiation effects  

SciTech Connect

Nitrogen-14 nuclear quadrupole resonance (NQR) was used in an attempt to detect the effects of ionizing radiation on organic material. Previously reported resonances for urea were detected at 2,913.32 {+-} 0.01 kHz and 2,347.88 {+-} 0.08 kHz with associated T{sub 2}* values 780 {+-} 20 {micro}s and 523 {+-} 24 {micro}s, respectively. The previously unreported {nu}{sub {minus}} line for urea-d{sup 4} was detected at 2,381 {+-} 0.04 Khz and used to determine accurately for the first time the values for the nuclear quadrupole coupling constant {chi} (3,548.74 {+-} 0.03 kHz) and the asymmetry parameter {eta} (0.31571 {+-} 0.00007) for urea-d{sup 4}. The inverse linewidth parameter T{sub 2}* for {nu}{sub +} was measured at 928 {+-} 23 {micro}s and for {nu}{sub {minus}} at 721 {+-} 12 {micro}s. Townes and Dailey analysis was performed and urea-d{sup 4} exhibits a 0.004 increase in lone pair electronic density and a slight decrease in N-H bond electronic density, as compared to urea, probably due to the mass difference. A relationship is proposed, referred to as NQR linewidth analysis, between the dynamic spin relaxation times T{sub 2} and T{sub 2}* and the widths of the distributions of the NQR parameters. Linewidth analysis is presented as a tool for possible use in future NQR work in all area, not just radiation effects. This relationship is tested using sodium nitrite T{sub 2} and T{sub 2}* values for {nu}{sub {minus}} and {nu}{sub {minus}} as a function of temperature.

Iselin, L.H.

1995-12-01

82

Nuclear quadrupole quantum beat spectroscopy in the electronic ground state of a polyatomic molecule by an IR-UV double resonance method  

NASA Astrophysics Data System (ADS)

The feasibility of determining nuclear quadrupole hyperfine splittings in the ground electronic state of a polyatomic molecule using a double resonance quantum beat method has been demonstrated. Pyrimidine molecules were coherently excited into single rotational states of the S 0 20 1 (13a 1) vibrational level. The resulting hyperfine level coherences were then probed, after a variable time delay, by excitation to the S 1 O 0 level with subsequent fluorescence detection. Analysis showed that the quadrupole structure in the 20 1 (13a 1) level is similar to that previously measured in the vibrational ground state. Applications of this method and possible experimental extensions are discussed.

Carter, Robert T.; Walther, Th.; Bitto, H.; Huber, J. Robert

1995-06-01

83

Nuclear Quadrupole Interactions of 7Li and 51V in a Li3VO4 Single Crystal Studied by Nuclear Magnetic Resonance  

NASA Astrophysics Data System (ADS)

The rotation patterns of the nuclear magnetic resonances of 7Li (I=3/2) and 51V (I=7/2) in the nonlinear optical Li3VO4 single crystal were measured in two mutually perpendicular crystal planes. From these results, the quadrupole coupling constants and the asymmetry parameters at room temperature were determined for the first time as follows: e2qQ/h=53.68± 2 kHz and ?=0.169 for 7Li, and e2qQ/h=1.44± 2 MHz and ?=0 for 51V. The symmetry for the electric field gradient (EFG) of V ions surrounded by four oxygen atoms is higher than that of Li ions surrounded by four oxygen atoms. The principal axes of the EFG tensor are a=Y, b=Z, c=X for 7Li, and a=b=X, c=Z for 51V nucleus. Also, the 7Li and the 51V spin-lattice relaxation rates were measured, and the behavior is quite similar for both nuclei. The measured relaxation rate was found to be linear in the square of the temperature. The Raman process with a T2 dependence is considered to be more effective than the direct process for nuclear quadrupole relaxation.

Lim, Ae Ran; Park, Sung Ho; Kim, Jung Nam; Jang, Min Su

2003-02-01

84

First-principles study of boron oxygen hole centers in crystals: Electronic structures and nuclear hyperfine and quadrupole parameters  

SciTech Connect

The electronic structures, nuclear hyperfine coupling constants, and nuclear quadrupole parameters of fundamental boron oxygen hole centers (BOHCs) in zircon (ZrSiO{sub 4}, I4{sub 1}/amd) and calcite (CaCO{sub 3}, R3c) have been investigated using ab initio Hartree-Fock (HF) and various density functional theory (DFT) methods based on the supercell models with all-electron localized basis sets. Both exact HF exchange and appropriate correlation functionals are important in describing the BOHCs, and the parameter-free hybrid method based on Perdew, Burke, and Ernzerhof density functionals (PBE0) turns out to be the best DFT method in reproducing the electron paramagnetic resonance (EPR) data. Our results reveal three distinct types of simple-spin (S = 1/2) [BO{sub 3}]{sup 2-} centers in calcite: (i) the classic [BO{sub 3}]{sup 2-} radical with the D{sub 3h} symmetry and the unpaired spin equally distributed on the three oxygen atoms (i.e. the O{sub 3}{sup 5-} type); (ii) the previously reported [BO{sub 2}]{sup 0} center with the unpaired spin equally distributed on two of the three oxygen atoms (O{sub 2}{sup 3-}); and (iii) a new variety with {approx}90% of its unpaired spin localized on one (O{sup -}) of the three oxygen atoms with a long B-O bond (1.44 A). Calculations confirm the unusual [BO{sub 4}]{sup 0} center in zircon and show it to arise from a highly distorted configuration with 90% of the unpaired spin on one oxygen atom that has a considerably longer B-O bond (1.68 A) than its three counterparts (1.45 A). The calculated magnitudes and directions of {sup 11}B and {sup 17}O hyperfine coupling constants and nuclear quadrupole constants for the [BO{sub 4}]{sup 0} center in zircon are in excellent agreement with the 15 K EPR experimental data. These BOHCs are all characterized by a small negative spin density on the central B atom arising from spin polarization. Our calculations also demonstrate that the spin densities on BOHCs are affected substantially by crystalline environments, and so periodic boundary treatment, such as the supercell scheme, is a must in accounting for the electronic and spin structures of BOHCs in crystals. These atomistic and electronic models of BOHCs in the crystalline matrices provide new insights into their precursors and counterparts in glasses and other amorphous materials.

Li Zucheng; Pan Yuanming [Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2 (Canada)

2011-09-15

85

Understanding the congener-specific toxicity in polychlorinated dibenzo-p-dioxins: chlorination pattern and molecular quadrupole moment.  

PubMed

It is well known that the biological activities and toxicities of planar polychlorinated aromatic compounds are extremely sensitive to chlorination pattern. Although their toxic responses have been correlated with the relative affinity for the receptor, the origin of this congener specificity is not well understood. We present a general interpretation of the congener-specific activity in polychlorinated dibenzo-p-dioxins, which concludes that molecular electrostatics is the principal factor determining the structure-activity relationship in this highly controversial environmental pollutant even though this electrostatic interaction represents only a part of the total interaction energy. Through calculations of the molecular charge distribution in the complete set of 76 dioxin congeners, we show that all active congeners share a unique charge distribution pattern, which is quantitatively described in terms of the molecular quadrupole moment (QM). The QM of dioxins changes sensitively and systematically with chlorination pattern. The three-dimensional electrostatic interactions at the receptor-binding site, which are optimized at a specific QM pattern represented by that of 2,3,7,8-tetrachlorodibenzo-p-dioxin, could explain the congener specificity in the binding affinity and toxicity. Although the polarizability also changes systematically with chlorination, it can only account for the effect of the degree of chlorination, not the congener specificity. PMID:11772071

Mhin, Byung Jin; Lee, Jung Eun; Choi, Wonyong

2002-01-01

86

Nuclear quadrupole deformations and anisotropic angular correlations between K x rays and gamma rays  

Microsoft Academic Search

Anisotropic angular correlation between gamma rays and the K x rays following the K conversion from nuclei with large static deformations has been studied. A complete theoretical expression for 181Ta, the second known case of this phenomenon, is presented. This case involves several mixed nuclear transitions which result in 62% of the x rays arising from magnetic dipole internal-conversion processes

Ali E. Khalil

1983-01-01

87

Zeeman Effect of the Nuclear Quadrupole Resonance of 81Br in para-Bromophenol and 35Cl in paraChlorophenol  

Microsoft Academic Search

The Zeeman effect of the 81Br and 35Cl nuclear quadrupole resonance has been studied with high precision on single crystals of para-bromophenol and para-chlorophenol, respectively. The results substantially agree with previous x-ray and NQR studies of para-chlorophenol (x-ray studies are known only for this substance). In p-bromophenol, four physically inequivalent sites were found, instead of two, as reported by other

P. Bucci; P. Cecchi; A. Colligiani

1969-01-01

88

35Cl Nuclear Quadrupole Resonance and Thermally Activated Molecular Motion in the 2:1 Crystalline Complex of Antimony Trichloride with Benzene  

Microsoft Academic Search

Nuclear quadrupole resonance (NQR) spectra of chlorine and antimony in the 2SbCl3 · C6H6 complex and their temperature behavior between 77 K and the melting point were studied. The spectral lines of two nonequivalent SbCl3 moieties are compared with available X-ray diffraction data. An analysis of the temperature dependence of the resonant frequency and the spin–lattice relaxation time for 35Cl

V. A. Mokeeva

2002-01-01

89

The rotational spectra, molecular structures, and 201Hg nuclear quadrupole coupling constants of HgHCl and HgDCl  

NASA Astrophysics Data System (ADS)

High-resolution rotational spectra of 16 isotopic species of the gas phase van der Waals complex HgHCl have been measured using pulsed Fourier-transform microwave spectroscopy carried out in a Fabry-Perot cavity. The Hg-Cl distance is 4.097 Å in HgHCl and 4.112 Å in HgDCl, with the acid proton located between the two heavy atoms, analogous to the structures of previously studied rare gas-hydrogen halide complexes. Based on this structure, an effective van der Waals radius of 1.99 Å for mercury in HgHCl is determined. 201Hg nuclear quadrupole coupling constants were measured for two complexes: ?Hg (201HgH 35Cl)=+5.993 (165) MHz, and ?Hg(201HgD 35Cl) =+7.789 (165) MHz. From these constants, and from a similar measurement for 201HgHC 15N, we obtain the first experimental estimate of the Sternheimer shielding constant in the mercury atom ?? =-47(7). Force constants and normal frequencies for the van der Waals vibrational modes were also calculated and compared with those of rare gas-hydrogen chloride complexes.

Shea, J. A.; Campbell, E. J.

1984-12-01

90

Nuclear quadrupole deformations and anisotropic angular correlations between K x rays and gamma rays  

Microsoft Academic Search

Anisotropic angular correlation between gamma rays and the K x rays following the K conversion from nuclei with large static deformations has been studied. A complete theoretical expression for ¹⁸¹Ta, the second known case of this phenomenon, is presented. This case involves several mixed nuclear transitions which result in 62% of the x rays arising from magnetic dipole internal-conversion processes

Ali Khalil

1983-01-01

91

A no-tune no-match wideband probe for nuclear quadrupole resonance spectroscopy in the VHF range  

NASA Astrophysics Data System (ADS)

Nuclear quadrupole resonance (NQR) spectroscopy is a method for the characterization of chemical compounds containing so-called quadrupolar nuclei. Similar to nuclear magnetic resonance (NMR), the sample under investigation is irradiated with strong radiofrequency (RF) pulses, which stimulate the emission of weak RF signals from the quadrupolar nuclei. The signals are then amplified and Fourier transformed so as to obtain a spectrum. In principle, narrowband NQR spectra can be measured with NMR spectrometers. However, pure NQR signals require the absence of a static magnetic field and several special applications require the characterization of a substance over a large bandwidth, e.g. 50–100% of the central frequency, which is hardly possible with standard NMR equipment. Dedicated zero-field NQR equipment is not widespread and current concepts employ resonating probes which are tuned and matched over a wide range by using mechanical capacitors driven by stepper motors. While providing the highest signal to noise ratio (SNR) such probes are slow in operation and can only be operated from dedicated NMR consoles. We developed a low-cost NQR wideband probe without tuning and matching for applications in the very high frequency (VHF) range below 300?MHz. The probe coil was realized as part of a reactive network which approximates an exponential transmission line. The input reflection coefficient of the two developed prototype probe coils is ? 20?dB between 90–145?MHz and 74.5–99.5?MHz, respectively. Two wideband NQR spectra of published test substances were acquired with an SNR of better than 20?dB after sufficient averaging. The measured signals and the SNR correspond very well to the theoretically expected values and demonstrate the feasibility of the method. Because there is no need for tuning and matching, our probes can be operated easily from any available NMR console.

Scharfetter, Hermann; Petrovic, Andreas; Eggenhofer, Heidi; Stollberger, Rudolf

2014-12-01

92

First steps toward an understanding of «Cold» nuclear fusion  

Microsoft Academic Search

Summary  We point out that the first steps in understanding the recent results reported on cold nuclear fusion can be made by considering\\u000a the important role that the coherent interactions with the quantized e.m. field play in condensed matter. Indeed we find natural\\u000a mechanisms to decrease the Coulomb repulsion and to suppress the usual nuclear-fusion channels with respect to the transfer

T. Bressani; E. Del Giudice; G. Preparata

1989-01-01

93

Precision Muonic-Atom Measurements of Nuclear Quadrupole Moments and the Sternheimer Effect in Rare-Earth Atoms  

Microsoft Academic Search

The ground-state quadrupole moments of 151Eu, 153Eu, 155Gd, 157Gd, 159Tb, 163Dy, 167Er, 177Hf, 179Hf, 191Ir, and 193Ir were determined with an uncertainty of less than one percent by measuring the quadrupole hyperfine-splitting energies of muonic M x rays. The results are used to determine experimentally Sternheimer shielding factors for the 4f, 5d, and 6p electronic states of the respective atoms.

Y. Tanaka; R. M. Steffen; E. B. Shera; W. Reuter; M. V. Hoehn; J. D. Zumbro

1983-01-01

94

Nuclear spins, magnetic moments, and quadrupole moments of Cu isotopes from N=28 to N=46: Probes for core polarization effects  

SciTech Connect

Measurements of the ground-state nuclear spins and magnetic and quadrupole moments of the copper isotopes from {sup 61}Cu up to {sup 75}Cu are reported. The experiments were performed at the CERN online isotope mass separator (ISOLDE) facility, using the technique of collinear laser spectroscopy. The trend in the magnetic moments between the N=28 and N=50 shell closures is reasonably reproduced by large-scale shell-model calculations starting from a {sup 56}Ni core. The quadrupole moments reveal a strong polarization of the underlying Ni core when the neutron shell is opened, which is, however, strongly reduced at N=40 due to the parity change between the pf and g orbits. No enhanced core polarization is seen beyond N=40. Deviations between measured and calculated moments are attributed to the softness of the {sup 56}Ni core and weakening of the Z=28 and N=28 shell gaps.

Vingerhoets, P.; Avgoulea, M.; Bissell, M. L.; De Rydt, M.; Neyens, G. [Instituut voor Kern- en Stralingsfysica, K.U. Leuven, B-3001 Leuven (Belgium); Flanagan, K. T. [Instituut voor Kern- en Stralingsfysica, K.U. Leuven, B-3001 Leuven (Belgium); IPN Orsay, F-91940 Orsay Cedex (France); Billowes, J.; Cheal, B.; Mane, E. [School of Physics and Astronomy, The University of Manchester, Manchester M13 9PL (United Kingdom); Blaum, K.; Schug, M. [Max-Planck-Institut fuer Kernphysik, D-69117 Heidelberg (Germany); Brown, B. A. [National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824-1321 (United States); Forest, D. H.; Tungate, G. [School of Physics and Astronomy, The University of Birmingham, Birmingham B15 2TT (United Kingdom); Geppert, Ch.; Noertershaeuser, W. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Institut fuer Kernchemie, Johannes Gutenberg-Universitaet Mainz, D-55128 Mainz (Germany); Honma, M. [Center for Mathematical Sciences, University of Aizu, Tsuruga, Ikki-machi, Aizu-Wakamatsu, Fukushima 965-8580 (Japan); Kowalska, M. [Physics Department, CERN, CH-1211 Geneva 23 (Switzerland); Kraemer, J.; Krieger, A. [Institut fuer Kernchemie, Johannes Gutenberg-Universitaet Mainz, D-55128 Mainz (Germany)

2010-12-15

95

Nuclear Quadrupole Hyperfine Structure in HC14N/H14NC and DC15N/D15NC Isomerization: A Diagnostic Tool for Characterizing Vibrational Localization  

E-print Network

Large-amplitude molecular motions which occur during isomerization can cause significant changes in electronic structure. These variations in electronic properties can be used to identify vibrationally-excited eigenstates which are localized along the potential energy surface. This work demonstrates that nuclear quadrupole hyperfine interactions can be used as a diagnostic marker of progress along the isomerization path in both the HC14N/H14NC and DC15N/D15NC chemical systems. Ab initio calculations at the CCSD(T)/cc-pCVQZ level indicate that the hyperfine interaction is extremely sensitive to the chemical bonding of the quadrupolar 14N nucleus and can therefore be used to determine in which potential well the vibrational wavefunction is localized. A natural bonding orbital analysis along the isomerization path further demonstrates that hyperfine interactions arise from the asphericity of the electron density at the quadrupolar nucleus. Using the CCSD(T) potential surface, the quadrupole coupling constants of...

Wong, Bryan M

2010-01-01

96

Nuclear spins, magnetic moments and quadrupole moments of Cu isotopes from N = 28 to N = 46: probes for core polarization effects  

E-print Network

Measurements of the ground-state nuclear spins, magnetic and quadrupole moments of the copper isotopes from 61Cu up to 75Cu are reported. The experiments were performed at the ISOLDE facility, using the technique of collinear laser spectroscopy. The trend in the magnetic moments between the N=28 and N=50 shell closures is reasonably reproduced by large-scale shell-model calculations starting from a 56Ni core. The quadrupole moments reveal a strong polarization of the underlying Ni core when the neutron shell is opened, which is however strongly reduced at N=40 due to the parity change between the $pf$ and $g$ orbits. No enhanced core polarization is seen beyond N=40. Deviations between measured and calculated moments are attributed to the softness of the 56Ni core and weakening of the Z=28 and N=28 shell gaps.

P. Vingerhoets; K. T. Flanagan; M. Avgoulea; J. Billowes; M. L. Bissell; K. Blaum; B. A. Brown; B. Cheal; M. De Rydt; D. H. Forest; Ch. Geppert; M. Honma; M. Kowalska; J. Kramer; A. Krieger; E. Mane; R. Neugart; G. Neyens; W. Nortershauser; T. Otsuka; M. Schug; H. H. Stroke; G. Tungate; D. T. Yordanov

2010-11-24

97

Charge Dependence and Electric Quadrupole Effects on Single-Nucleon Removal in Relativistic and Intermediate Energy Nuclear Collisions  

NASA Technical Reports Server (NTRS)

Single nucleon removal in relativistic and intermediate energy nucleus-nucleus collisions is studied using a generalization of Weizsacker-Williams theory that treats each electromagnetic multipole separately. Calculations are presented for electric dipole and quadrupole excitations and incorporate a realistic minimum impact parameter, Coulomb recoil corrections, and the uncertainties in the input photonuclear data. Discrepancies are discussed. The maximum quadrupole effect to be observed in future experiments is estimated and also an analysis of the charge dependence of the electromagnetic cross sections down to energies as low as 100 MeV/nucleon is made.

Norbury, John W.

1992-01-01

98

Charge dependence and electric quadrupole effects on single-nucleon removal in relativistic and intermediate energy nuclear collisions  

NASA Technical Reports Server (NTRS)

Single-nucleon removal in relativistic and intermediate energy nucleus-nucleus collisions is studied using a generalization of Weizsacker-Williams theory that treats each electromagnetic multipole separately. Calculations are presented for electric dipole and quadrupole excitations and incorporate a realistic minimum impact parameter, Coulomb recoil corrections, and the uncertainties in the input photonuclear data. Discrepancies are discussed. The maximum quadrupole effect to be observed in future experiments is estimated and also an analysis of the charge dependence of the electromagnetic cross sections down to energies as low as 100 MeV/nucleon is made.

Norbury, J. W.; Townsend, L. W. (Principal Investigator)

1990-01-01

99

{sup 63}Cu and {sup 197}Au nuclear quadrupole moments from four-component relativistic density-functional calculations using correct long-range exchange  

SciTech Connect

The electric field gradient in late transition metal compounds is incorrectly determined by most density functionals. We show that the coupling of short-range density functional based with long-range wave function based methods using a reparametrization of the Coulomb-attenuated Becke three-parameter Lee-Yang-Parr approximation gives reliable results for the electric field gradients of copper and gold for a series of compounds. This results in nuclear quadrupole moments of -0.208 b for {sup 63}Cu and +0.526 b for {sup 197}Au in good agreement with experimental values of -0.220(15) and +0.547(16)b, respectively.

Thierfelder, Christian; Schwerdtfeger, Peter; Saue, Trond [Centre of Theoretical Chemistry and Physics, Institute of Fundamental Sciences, Massey University (Auckland Campus), Private Bag 102904, North Shore MSC, Auckland (New Zealand); Laboratoire de Chimie Quantique, Institut de Chimie de Strasbourg, LC3-UMR7177 CNRS/Universite Louis Pasteur, 4 Rue Blaise Pascal, F-67000 Strasbourg (France)

2007-09-15

100

Nuclear Quadrupole Resonance and Electron Spin Resonance in C(NH2)3Al(SO4)2.6H2O and Isomorphous Compounds  

Microsoft Academic Search

The temperature dependence of the nuclear quadrupole coupling parameters, eQqh, of Al and Ga has been measured in the ferroelectric compound C(NH2)3Al(SO4)2.6H2O (GAlSH) and three other isomorphous compounds that result when Ga replaces Al and SeO4 replaces SO4. Measurements were also made on deuterated GAlSH. The temperature dependence of the electron spin resonance (ESR) of Cr3+, substituted for Al or

Gerald Burns

1961-01-01

101

Application of nuclear quadrupole resonance to the study of clathrates. sup 35 Cl NQR and crystallography of clathrated CCl sub 4  

Microsoft Academic Search

The ³⁵Cl nuclear quadrupole resonance (NQR) spectra of CClâ in more than 20 clathrates have been measured in the range 4-200 K. The crystal structures of CClâ\\/Dianin's compound (1), CClâ\\/Fe(AcAc)â (3), CClâ\\/Ni(SCN)â(3-MePy)â (4), and CClâ\\/Ni(exan)â(4,4â²-dm-2,2â²-bpy) (19) clathrates are also reported. Site symmetry and site multiplicity of the guest molecule in clathrates were determined by NQR spectroscopy and by x-ray crystallography.

Li Pang; E. A. C. Lucken; G. Bernardinelli

1990-01-01

102

17O nuclear quadrupole coupling constants of water bound to a metal ion: A gadolinium(III) case study  

NASA Astrophysics Data System (ADS)

Rotational correlation times of metal ion aqua complexes can be determined from O17 NMR relaxation rates if the quadrupole coupling constant of the bound water oxygen-17 nucleus is known. The rotational correlation time is an important parameter for the efficiency of Gd3+ complexes as magnetic resonance imaging contrast agents. Using a combination of density functional theory with classical and Car-Parrinello molecular dynamics simulations we performed a computational study of the O17 quadrupole coupling constants in model aqua ions and the [Gd(DOTA)(H2O)]- complex used in clinical diagnostics. For the inner sphere water molecule in the [Gd(DOTA)(H2O)]- complex the determined quadrupole coupling parameter ??1+?2/3 of 8.7MHz is very similar to that of the liquid water (9.0MHz ). Very close values were also predicted for the the homoleptic aqua ions of Gd3+ and Ca2+. We conclude that the O17 quadrupole coupling parameters of water molecules coordinated to closed shell and lanthanide metal ions are similar to water molecules in the liquid state.

Yazyev, Oleg V.; Helm, Lothar

2006-08-01

103

85Rb, 87Rb, and 17O nuclear-quadrupole-resonance study of Rb(H1-xDx)2PO4  

NASA Astrophysics Data System (ADS)

The 85Rb, 87Rb, and 17O nuclear-quadrupole-resonance frequencies and line shapes have been measured in RbH2PO4 and in Rb(H1-xDx)2PO4 (x=0.5,0.7) with the nuclear-quadrupole double-resonance technique. The results show that in the paraelectric phase the Rb+ ions move in a single-site potential, whereas the protons are dynamically disordered between two sites in the O-H...O hydrogen bonds. The ferroelectric phase transition in RbH2PO4 is associated with the freezing out of the proton motion in the O-H...O hydrogen bonds that induces a shift of the Rb+ ions along the ferroelectric axis. In the partially deuterated compounds the O-H...O hydrogen bonds are practically identical to the ones in pure RbH2PO4 and are thus only weakly influenced by the surrounding O-D...O bonds. The O-D...O bonds are, however, significantly more asymmetric and presumably longer than the O-H...O bonds.

Seliger, J.; Žagar, V.; Blinc, R.; Schmidt, V. H.

1990-09-01

104

Detection of an Unconventional Superconducting Phase in the Vicinity of the Strong First-Order Magnetic Transition in CrAs Using ^{75}As-Nuclear Quadrupole Resonance.  

PubMed

Pressure-induced superconductivity was recently discovered in the binary helimagnet CrAs. We report the results of measurements of nuclear quadrupole resonance for CrAs under pressure. In the vicinity of the critical pressure P_{c} between the helimagnetic (HM) and paramagnetic (PM) phases, a phase separation is observed. The large internal field remaining in the phase-separated HM state indicates that the HM phase disappears through a strong first-order transition. This indicates the absence of a quantum critical point in CrAs; however, the nuclear spin-lattice relaxation rate 1/T_{1} reveals that substantial magnetic fluctuations are present in the PM state. The absence of a coherence effect in 1/T_{1} in the superconducting state provides evidence that CrAs is the first Cr-based unconventional superconductor. PMID:25839303

Kotegawa, Hisashi; Nakahara, Shingo; Akamatsu, Rui; Tou, Hideki; Sugawara, Hitoshi; Harima, Hisatomo

2015-03-20

105

Ferromagnetic critical behavior in U(Co1-xFex)Al (0 ?x ?0.02 ) studied by 59Co nuclear quadrupole resonance measurements  

NASA Astrophysics Data System (ADS)

In order to investigate physical properties around a ferromagnetic (FM) quantum transition point and a tricritical point (TCP) in the itinerant-electron metamagnetic compound UCoAl, we have performed the 59Co nuclear quadrupole resonance (NQR) measurement for the Fe-substituted U(Co1-xFex)Al(x =0 ,0.5 ,1 ,and2 %) in zero external magnetic field. The Fe concentration dependence of 59Co -NQR spectra at low temperatures indicates that the first-order FM transition occurs at least above x =1 % . The magnetic fluctuations along the c axis detected by the nuclear spin-spin relaxation rate 1 /T2 exhibit an anomaly at Tmax˜20 K and enhance with increasing x . These results are in good agreement with theoretical predictions and indicate the presence of prominent critical fluctuations at the TCP in this system.

Karube, K.; Hattori, T.; Ishida, K.; Kimura, N.

2015-02-01

106

Understanding the nature of nuclear power plant risk  

SciTech Connect

This paper describes the evolution of understanding of severe accident consequences from the non-mechanistic assumptions of WASH-740 to WASH-1400, NUREG-1150, SOARCA and today in the interpretation of the consequences of the accident at Fukushima. As opposed to the general perception, the radiological human health consequences to members of the Japanese public from the Fukushima accident will be small despite meltdowns at three reactors and loss of containment integrity. In contrast, the radiation-related societal impacts present a substantial additional economic burden on top of the monumental task of economic recovery from the nonnuclear aspects of the earthquake and tsunami damage. The Fukushima accident provides additional evidence that we have mis-characterized the risk of nuclear power plant accidents to ourselves and to the public. The human health risks are extremely small even to people living next door to a nuclear power plant. The principal risk associated with a nuclear power plant accident involves societal impacts: relocation of people, loss of land use, loss of contaminated products, decontamination costs and the need for replacement power. Although two of the three probabilistic safety goals of the NRC address societal risk, the associated quantitative health objectives in reality only address individual human health risk. This paper describes the types of analysis that would address compliance with the societal goals. (authors)

Denning, R. S. [Ohio State Univ., 201 West 19th Avenue, Columbus, OH 43210-1142 (United States)

2012-07-01

107

Nuclear-quadrupole double-resonance study of RbH2PO4 in the supercooled high-temperature monoclinic phase  

NASA Astrophysics Data System (ADS)

Rubidium nuclear-quadrupole-resonance (NQR) spectra have been measured in the high-temperature monoclinic phase of RbH2PO4 above Tp=86 °C and also in the supercooled high-temperature phase below Tp. At the transition into the high-temperature phase, the rubidium quadrupole-coupling constants drop by a factor of 5. The high-temperature phase is metastable below Tp. The kinetics of the transformation of the metastable phase into the stable tetragonal phase in a polycrystalline sample is determined at room temperature from the time dependence of the rubidium NQR spectra. A comparison of the present rubidium NQR data in the high-temperature monoclinic RbH2PO4 with the rubidium NQR data in monoclinic RbD2PO4 suggests that at low temperatures, supercooled monoclinic RbH2PO4 may be isostructural with the phase III of monoclinic RbD2PO4 whereas above Tp RbH2PO4 may be isostructural with phase II of RbD2PO4.

Seliger, J.; Žagar, V.; Blinc, R.

1993-06-01

108

Application of nuclear quadrupole resonance to the study of clathrates. sup 35 Cl NQR and crystallography of clathrated CCl sub 4  

SciTech Connect

The {sup 35}Cl nuclear quadrupole resonance (NQR) spectra of CCl{sub 4} in more than 20 clathrates have been measured in the range 4-200 K. The crystal structures of CCl{sub 4}/Dianin's compound (1), CCl{sub 4}/Fe(AcAc){sub 3} (3), CCl{sub 4}/Ni(SCN){sub 2}(3-MePy){sub 4} (4), and CCl{sub 4}/Ni(exan){sub 2}(4,4{prime}-dm-2,2{prime}-bpy) (19) clathrates are also reported. Site symmetry and site multiplicity of the guest molecule in clathrates were determined by NQR spectroscopy and by x-ray crystallography. The degree of host-guest interaction was estimated from the NQR frequency shifts. The libration frequencies of the guest molecules in trigonal cavities were determined from NQR frequencies by Bayer-Kushida theory analysis.

Pang, Li; Lucken, E.A.C.; Bernardinelli, G. (Univ. de Geneve (Switzerland))

1990-11-21

109

Variable-Pitch Rectangular Cross-section Radiofrequency Coils for the Nitrogen-14 Nuclear Quadrupole Resonance Investigation of Sealed Medicines Packets  

PubMed Central

The performance of rectangular radio frequency (RF) coils capable of being used to detect nuclear quadrupole resonance (NQR) signals from blister packs of medicines has been compared. The performance of a fixed-pitch RF coil was compared with that from two variable-pitch coils, one based on a design in the literature and the other optimized to obtain the most homogeneous RF field over the whole volume of the coil. It has been shown from 14N NQR measurements with two medicines, the antibiotic ampicillin (as trihydrate) and the analgesic medicine Paracetamol, that the latter design gives NQR signal intensities almost independent of the distribution of the capsules or pills within the RF coil and is therefore more suitable for quantitative analysis. PMID:23057555

2012-01-01

110

Evaluation of nitrogen nuclear hyperfine and quadrupole coupling parameters for the proximal imidazole in myoglobin-azide, -cyanide, and -mercaptoethanol complexes by electron spin echo envelope modulation spectroscopy.  

PubMed

Electron spin echo envelope modulation (ESEEM) spectroscopy and computer simulation of spectra has been used to evaluate the nitrogen nuclear hyperfine and quadrupole coupling parameters for the proximal imidazole nitrogen directly coordinated to iron in three low-spin heme complexes, myoglobin-azide, -cyanide, and -mercaptoethanol (MbN3, MbCN, and MbRS). The variability in the weak electron-nuclear coupling parameters reveals the electronic flexibility within the heme group that depends on properties of the exogenous ligands. For example, the isotropic component of the nitrogen nuclear hyperfine coupling ranges from 4.4 MHz for MbN3 to 2.2 MHz for both MbCN and MbRS. The weaker coupling in MbCN and MbRS is taken as evidence for delocalization of unpaired electron spin from iron into the exogenous anionic ligands. The value of e2Qq, the nuclear quadrupole coupling constant for the axial imidazole nitrogen in MbCN and MbRS, was 2.5 MHz but was significantly larger, 3.2 MHz, in MbN3. This large value is considered evidence for a weakened sigma bond between the proximal imidazole and ferric iron in this form, and for a feature contributing to the origin of the high spin-low spin equilibrium exhibited by MbN3 [Beetlestone, J., & George, P. (1964) Biochemistry 5, 707-714]. The ESEEM results have allowed a correlation to be made between the orientation of the g tensor axes, the orientation of the p-pi orbital of the proximal imidazole nitrogen, and sigma- and pi-bonding features of the axial ligands. Furthermore, the proximal imidazole is suggested to act as a pi-acceptor in low-spin heme complexes in order to support strong sigma electron donation from the lone pair orbital to iron. An evaluation of the nitrogen nuclear hyperfine coupling parameters for the porphyrin pyrrole sites in MbRS reveals a large inequivalence in isotropic components consistent with an orientation of rhombic axes (and g tensor axes) that eclipses the Fe-Npyrrole vector directions. PMID:8395204

Magliozzo, R S; Peisach, J

1993-08-24

111

Fermilab Tevatron quadrupoles  

SciTech Connect

Details on the design, construction, and performance tests of Energy Saver/Doubler quadrupoles are presented along with recent data from the test of a special high gradient low beta prototype quadrupole.

Cooper, W.E.; Fisk, H.E.; Gross, D.A.; Lundy, R.A.; Schmidt, E.E.; Turkot, F.

1983-03-01

112

Electronic Structure and Nuclear Quadrupole Interactions in Cocaine Hydrochloride(C_17H_21NO_4HCl)  

NASA Astrophysics Data System (ADS)

The electronic structure of C_17H_21NO_4HCl has been investigated using the Hartree-Fock-Roothaan variational procedure. The position of the hydrogen atom, associated with HCl, which is not available from structural data, has been determined through total energy optimization with two likely positions obtained, one at 1.06 A from the nitrogen atom and the other at 1.73 A from the latter and 1.35 A from chlorine, these positions indicating bonding of H with nitrogen and chlorine respectively. The former position is found to be significantly more stable(about 0.54 eV) compared to the latter and leads to quadrupole coupling constants and asymmetry parameters of -1.422 MHz and 0.281 for the ^14N nucleus and -8.609 MHz and 0.146 for ^35Cl. These results are in good agreement with the corresponding experimental magnitudes(J. P. Yesinowski, M. L. Buess, A. N. Garroway, M. Ziegeweid and A. Pines, Analytical Chemistry 67), 2256 (1995). of 1.1780 MHz, 0.2632 and 5.027 MHz, 0.2, demonstrating that the correct picture in this compound is one of hydrogen leaving the chlorine and getting attached to nitrogen, as suggested earlier^1.

Pati, Ranjit; Sahoo, N.; Das, T. P.; Ray, S. N.

1998-03-01

113

Nuclear Propulsion for Space, Understanding the Atom Series.  

ERIC Educational Resources Information Center

The operation of nuclear rockets with respect both to rocket theory and to various fuels is described. The development of nuclear reactors for use in nuclear rocket systems is provided, with the Kiwi and NERVA programs highlighted. The theory of fuel element and reactor construction and operation is explained with particular reference to rocket…

Corliss, William R.; Schwenk, Francis C.

114

Bioactivity-integrated ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry for the identification of nuclear factor-?B inhibitors and ?2 adrenergic receptor agonists in Chinese medicinal preparation Chuanbeipipa dropping pills.  

PubMed

A simple and dual-target method based on ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry combined with dual-bioactive [nuclear factor-?B (NF-?B) and ?2 -adrenergic receptor] luciferase reporter assay systems was developed to rapidly characterize the chemical structure of various bioactive compounds of TCM preparations. Chuanbeipipa dropping pills, a traditional Chinese medicine preparation used for the clinical therapy of chronic obstructive lung disease and cough caused by bronchial catarrh, was analyzed with this method. Potential anti-inflammatory and spasmolytic constituents were screened using NF-?B and ?2 -adrenergic receptor activity luciferase reporter assay systems and simultaneously identified according to the time-of-flight mass spectrometry data. One ?2-adrenergic receptor agonist (ephedrine) and two structural types of NF-?B inhibitors (platycosides derivatives and ursolic acid derivatives) were characterized. Platycodin D3 and E were considered new NF-?B inhibitors. Further cytokine and chemokine detection confirmed the anti-inflammatory effects of the potential NF-?B inhibitors. Compared with conventional fingerprints, activity-integrated fingerprints that contain both chemical and bioactive details offer a more comprehensive understanding of the chemical makeup of plant materials. This strategy clearly demonstrated that multiple bioactivity-integrated fingerprinting is a powerful tool for the improved screening and identification of potential multi-target lead compounds in complex herbal medicines. PMID:23483566

Dong, Linyi; Luo, Yi; Cheng, Binfeng; Zhang, Yaoshu; Zhang, Ning; Hou, Yuanyuan; Jiang, Min; Luo, Guoan; Bai, Gang

2013-08-01

115

Microfractionation bioactivity-based ultra performance liquid chromatography/quadrupole time-of-flight mass spectrometry for the identification of nuclear factor-?B inhibitors and ?2 adrenergic receptor agonists in an alkaloidal extract of the folk herb Alstonia scholaris.  

PubMed

Traditional Chinese medicines (TCMs) are generally considered complementary or alternative remedies in most Western countries. The constituents of TCMs are hard to define, and their efficacy is difficult to appraise. Thus, the development of suitable methods for evaluating the relationship between bioactivity and the chemical makeup of complex TCM mixtures remains a great challenge. In the present work, the bioactivity-integrated fingerprints of alkaloidal leaf extracts of Alstonia scholaris, a folk medicinal herb for chronic respiratory diseases, were established by ultra performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF). This method was coupled with two dual-luciferase reporter assay systems to show nuclear factor-?B (NF-?B) inhibition and ?(2) adrenergic receptor (?(2)AR) activation. Using UPLC-Q/TOF, 18 potential candidates were identified according to unique mass spectrometric fragmentation. After in vitro biological evaluation, several indole alkaloids with anti-inflammatory and anti-asthmatic properties were found, including akuammidine, (E)-alstoscholarine, and (Z)-alstoscholarine. Compared with conventional fingerprints, the microfractionation based bioactivity-integrated fingerprints that contain both chemical and bioactivity details offer a more comprehensive understanding of the chemical makeup of plant materials. This strategy clearly demonstrated that dual bioactivity-integrated fingerprinting is a powerful tool for the improved screening and identification of potential dual-target lead compounds in complex herbal medicines. PMID:23122407

Hou, Yuanyuan; Cao, Xuelin; Wang, Liqiang; Cheng, Binfeng; Dong, Linyi; Luo, Xiaodong; Bai, Gang; Gao, Wenyuan

2012-11-01

116

Sources of Nuclear Fuel, Understanding the Atom Series.  

ERIC Educational Resources Information Center

A brief outline of the historical landmarks in nuclear physics leading to the use of nuclear energy for peaceful purposes introduces this illustrated booklet. The distribution of known sources of uranium ores is mapped and some details about the geology of each geographical area given. Methods of prospective, mining, milling, refining, and fuel…

Singleton, Arthur L., Jr.

117

Nuclear Reactors for Space Power, Understanding the Atom Series.  

ERIC Educational Resources Information Center

The historical development of rocketry and nuclear technology includes a specific description of Systems for Nuclear Auxiliary Power (SNAP) programs. Solar cells and fuel cells are considered as alternative power supplies for space use. Construction and operation of space power plants must include considerations of the transfer of heat energy to…

Corliss, William R.

118

Standard test method for analysis of isotopic composition of uranium in nuclear-grade fuel material by quadrupole inductively coupled plasma-mass spectrometry  

E-print Network

1.1 This test method is applicable to the determination of the isotopic composition of uranium (U) in nuclear-grade fuel material. The following isotopic weight percentages are determined using a quadrupole inductively coupled plasma-mass spectrometer (Q-ICP-MS): 233U, 234U, 235U, 236U, and 238U. The analysis can be performed on various material matrices after acid dissolution and sample dilution into water or dilute nitric (HNO3) acid. These materials include: fuel product, uranium oxide, uranium oxide alloys, uranyl nitrate (UNH) crystals, and solutions. The sample preparation discussed in this test method focuses on fuel product material but may be used for uranium oxide or a uranium oxide alloy. Other preparation techniques may be used and some references are given. Purification of the uranium by anion-exchange extraction is not required for this test method, as it is required by other test methods such as radiochemistry and thermal ionization mass spectroscopy (TIMS). This test method is also described i...

American Society for Testing and Materials. Philadelphia

2000-01-01

119

Exact analysis of polycrystalline electron spin echo envelope modulation including mutual nuclear arrangements and quadrupole interactions and its application to methyl radicals in irradiated crystals of lithium acetate dihydrate  

NASA Astrophysics Data System (ADS)

The method of exact analysis including mutual nuclear arrangements and quadrupole interactions is developed for electron spin echo envelope modulation (ESEM) from polycrystalline samples using the formulation in an arbitrary laboratory coordinate system, which makes it possible to perform an exact angular integration. In order to assess polycrystalline ESEM by comparing with electron nuclear double resonance (ENDOR) data, the method is applied to analyze deuterium hyperfine modulation on the two-pulse electron spin echo (ESE) envelope decay observed for methyl radicals radiolytically produced in CD3COOLi ? 2H2O and CH3COOLi ? 2D2O. The results are totally consistent with our previous study by single crystal 1H ENDOR. Through this application, importance of the nuclear quadrupole term is also shown based on the exact method. The rigid deuterons in the water of crystallization show a marked quadrupole effect as compared with those in the freely rotating CD3 group. The contributions from the distant nuclei to the modulation pattern are also studied by the exact method using the crystallographic data. We have further clarified that the origin of the disagreement of a previous Li ESEM with our ENDOR is mainly in the use of a unit spin density on the spin probe despite its reduction by delocalization to the environment.

Iwasaki, Machio; Toriyama, Kazumi

1985-06-01

120

Theory of Nuclear Quadrupole Interaction in Trifluoro-Aminoboranes [BF3NH3-X(CH3)X  

Microsoft Academic Search

The understanding of the catalytic properties of BF3 of great current interest require information about the electronic structures of the associated complexes of BF3 with the molecules involved in the process. In this work we have studied the corresponding complexes for methylamines using the Hartree-Fock procedure combined with many-body perturbation theory. Results will be presented for the natures of the

Mahendra K. Mahanti; Archana Dubey; H. P. Saha; Lee Chow; R. H. Scheicher; R. H. Pink; Dip N. Mahato; M. B. Huang; T. P. Das

2006-01-01

121

Study of the extra-ionic electron distributions in semi-metallic structures by nuclear quadrupole resonance techniques  

NASA Technical Reports Server (NTRS)

A straightforward self-consistent method was developed to estimate solid state electrostatic potentials, fields and field gradients in ionic solids. The method is a direct practical application of basic electrostatics to solid state and also helps in the understanding of the principles of crystal structure. The necessary mathematical equations, derived from first principles, were presented and the systematic computational procedure developed to arrive at the solid state electrostatic field gradients values was given.

Murty, A. N.

1976-01-01

122

Empirical investigation of extreme single-particle behavior of nuclear quadrupole moments in highly collective A similar to 150 superdeformed bands  

E-print Network

The intrinsic quadrupole moment Q(0) of superdeformed rotational bands in A similar to 150 nuclei depends on the associated single-particle configuration. We have derived an empirical formula based on the additivity of ...

Clark, S. T.; Hackman, G.; Floor, S. N.; Norris, J.; Sanders, Stephen J.

2001-10-01

123

Towards a better understanding of nuclear processes based on proteomics.  

PubMed

The complex structural and functional organisation of the brain warrants the application of high-throughput approaches to study its functional alterations in physiological and pathological conditions. Such approaches have greatly benefited from advances in proteomics and genomics, and from their combination with computational modelling. They have been particularly instrumental for the analysis of processes such as the post-translational modification (PTM) of proteins, a critical biological process in the nervous system that remains not well studied. Protein PTMs are dynamic covalent marks that can be induced by activity and allow the maintenance of a trace of this activity. In the nucleus, they can modulate histone proteins and the components of the transcriptional machinery, and thereby contribute to regulating gene expression. PTMs do however need to be tightly controlled for proper chromatin functions. This review provides a synopsis of methods available to study PTMs and protein expression based on high-throughput mass spectrometry (MS), and covers basic concepts of traditional 'shot-gun'-based MS. It describes classical and emerging proteomic approaches such as multiple reaction monitoring and electron transfer dissociation, and their application to the analyses of nuclear processes in the brain. PMID:20730591

Tweedie-Cullen, Ry Y; Mansuy, Isabelle M

2010-11-01

124

Understanding Nuclear Receptor Form and Function Using Structural Biology  

PubMed Central

Nuclear receptors (NR) are a major transcription factor family whose members selectively bind small molecule lipophilic ligands and transduce those signals into specific changes in gene programs. For over two decades, structural biology efforts were directed exclusively on the individual ligand binding domains (LBDs) or DNA binding domains (DBDs) of NRs. These analyses revealed the basis for both ligand and DNA binding, and also revealed receptor conformations representing both the activated and repressed states. Additionally, crystallographic studies explained how NR LBD surfaces recognize discrete portions of transcriptional coregulators. The many structural snapshots of LBDs have also guided the development of synthetic ligands with therapeutic potential. Yet, the exclusive structural focus on isolated NR domains has made it difficult to conceptualize how all the NR polypeptide segments are coordinated physically and functionally in the context of receptor quaternary architectures. Newly emerged crystal structures of the PPAR?-RXR? heterodimer and HNF-4? homodimer have recently revealed the higher order organizations of these receptor complexes on DNA, as well as the complexity and uniqueness of their domain-domain interfaces. These emerging structural advances promise to better explain how signals in one domain can be allosterically transmitted to distal receptor domains, also providing much better frameworks for guiding future drug discovery efforts. PMID:24103914

Rastinejad, Fraydoon; Huang, Pengxiang; Chandra, Vikas; Khorasanizadeh, Sepideh

2013-01-01

125

Three-Dimensional Nuclear Chart--Understanding Nuclear Physics and Nucleosynthesis in Stars  

ERIC Educational Resources Information Center

Three-dimensional (3D) nuclear charts were created using toy blocks, which represent the atomic masses per nucleon number and the total half-lives for each nucleus in the entire region of the nuclear mass. The bulk properties of the nuclei can be easily understood by using these charts. Subsequently, these charts were used in outreach activities…

Koura, Hiroyuki

2014-01-01

126

Progress in Understanding the Nuclear Equation of State at the Quark Level  

SciTech Connect

At the present time there is a lively debate within the nuclear community concerning the relevance of quark degrees of freedom in understanding nuclear structure. We outline the key issues and review the impressive progress made recently within the framework of the quark-meson coupling model. In particular, we explain in quite general terms how the modification of the internal structure of hadrons in-medium leads naturally to three- and four-body forces, or equivalently, to density dependent effective interactions.

A.W. Thomas; P.A.M. Guichon

2007-01-03

127

Nuclear quadrupole spin-lattice relaxation in Bi{sub 4}Ge{sub 3}O{sub 12} single crystals doped with atoms of d or f elements. Crystal field effects in compounds exhibiting anomalous magnetic properties  

SciTech Connect

The nuclear quadrupole spin-lattice relaxation was studied in the range 4.2-300 K for single crystals of Bi{sub 4}Ge{sub 3}O{sub 12} doped with minor amounts (the tenth fractions of mol%) of paramagnetic atoms of Cr, Nd, and Gd. Unusual spin dynamic features were recently found for these crystals at room temperature: a dramatic (up to 8-fold) increase in the effective nuclear quadrupole spin-spin relaxation time T{sub 2}* occurred upon doping the pure Bi{sub 4}Ge{sub 3}O{sub 12} sample. Unlike T{sub 2}*, the effective spin-lattice relaxation time T{sub 1}* at room temperature differs insignificantly for both doped and pure samples. But at lower temperatures, the samples exhibit considerably different behavior of the spin-lattice relaxation with temperature, which is caused by different contributions to the relaxation process of the dopant paramagnetic atoms. The distinctive maximum in the temperature dependence of the spin-lattice relaxation time for the Nd-doped crystal is shown to result from the crystal electric field effects.

Orlov, V. G., E-mail: orlov@mbslab.kiae.ru; Sergeev, G. S. [Russian Research Center 'Kurchatov Institute' (Russian Federation); Asaji, Tetsuo [Nihon University, Department of Chemistry, College of Humanities and Sciences (Japan); Kravchenko, E. A. [Russian Academy of Sciences, Institute of General and Inorganic Chemistry (Russian Federation); Kargin, Yu. F. [Russian Academy of Sciences, State Institute of Metallurgy and Material Science (Russian Federation)

2010-02-15

128

Detection of an Unconventional Superconducting Phase in the Vicinity of the Strong First-Order Magnetic Transition in CrAs Using As 75 -Nuclear Quadrupole Resonance  

NASA Astrophysics Data System (ADS)

Pressure-induced superconductivity was recently discovered in the binary helimagnet CrAs. We report the results of measurements of nuclear quadrupole resonance for CrAs under pressure. In the vicinity of the critical pressure Pc between the helimagnetic (HM) and paramagnetic (PM) phases, a phase separation is observed. The large internal field remaining in the phase-separated HM state indicates that the HM phase disappears through a strong first-order transition. This indicates the absence of a quantum critical point in CrAs; however, the nuclear spin-lattice relaxation rate 1 /T1 reveals that substantial magnetic fluctuations are present in the PM state. The absence of a coherence effect in 1 /T1 in the superconducting state provides evidence that CrAs is the first Cr-based unconventional superconductor.

Kotegawa, Hisashi; Nakahara, Shingo; Akamatsu, Rui; Tou, Hideki; Sugawara, Hitoshi; Harima, Hisatomo

2015-03-01

129

High gradient superconducting quadrupoles  

SciTech Connect

Prototype superconducting quadrupoles with a 5 cm aperture and gradient of 16 kG/cm have been built and tested as candidate magnets for the final focus at SLC. The magnets are made from NbTi Tevatron style cable with 10 inner and 14 outer turns per quadrant. Quench performance and multipole data are presented. Design and data for a low current, high gradient quadrupole, similar in cross section but wound with a cable consisting of five insulated conductors are also discussed.

Lundy, R.A.; Brown, B.C.; Carson, J.A.; Fisk, H.E.; Hanft, R.H.; Mantsch, P.M.; McInturff, A.D.; Remsbottom, R.H.

1987-07-01

130

Resonant Quadrupole Peter Cameron -BNL  

E-print Network

Resonant Quadrupole Monitor Peter Cameron - BNL #12;LARP Workshop at FNAL6/9/2003 2 Resonant BPM · Resonate above coherent spectrum #12;LARP Workshop at FNAL6/9/2003 3 Basic Method - Quadrupole Oscillations, Quadrupole BTF possible with this system. #12;LARP Workshop at FNAL6/9/2003 4 Dynamic Range Problem · Dynamic

Large Hadron Collider Program

131

New Terms for a Common Understanding of De-Alerting: Launch Before or After Nuclear Detonation  

E-print Network

The discussion of de-alerting has been complicated by the absence of a common understanding and description of how the United States and the Russian Federation might employ their nuclear arsenals during the initial phases of a nuclear exchange. A resulting lack of universally agreed terminology has hindered diplomatic efforts to lower the operational status of nuclear forces and thus reduce the possibility of accidental, unauthorized or inadvertent use of nuclear weapons. The authoritative report, Reframing Nuclear De-Alert (published in 2009 by the EastWest Institute and sponsored by the governments of Switzerland and New Zealand), made it clear that differences in language and translation, combined with military secrecy, have created a confusion of definitions and terms even among experts. Thus the report made its first objective, "... to define the issue to reconcile differing views of the de-alert concept that may themselves hinder attempts to reduce the readiness of nuclear weapons. " 1 Reframing Nuclear De-Alert identified "Otvetno-Vstrechnyi Udar " (OVU), "Launch Under Attack " (LUA) and "Launch On Warning " (LOW) as the central concepts in

Steven Starr; Commander (ret.) Robert Green; Ernie Regehr; Colonel (ret.) Valery Yarynich; Robi

132

Variable Permanent Magnet Quadrupole  

SciTech Connect

A permanent magnet quadrupole (PMQ) is one of the candidates for the final focus lens in a linear collider. An over 120 T/m strong variable permanent magnet quadrupole is achieved by the introduction of saturated iron and a 'double ring structure'. A fabricated PMQ achieved 24 T integrated gradient with 20 mm bore diameter, 100 mm magnet diameter and 20 cm pole length. The strength of the PMQ is adjustable in 1.4 T steps, due to its 'double ring structure': the PMQ is split into two nested rings; the outer ring is sliced along the beam line into four parts and is rotated to change the strength. This paper describes the variable PMQ from fabrication to recent adjustments.

Mihara, T.; Iwashita, Y.; /Kyoto U.; Kumada, M.; /NIRS, Chiba; Spencer, C.M.; /SLAC

2007-05-23

133

Mapping Complexity Sources in Nuclear Power Plant Domains Understanding the sources of complexity in advanced Nuclear Power Plant (NPP) control rooms and their  

E-print Network

in advanced Nuclear Power Plant (NPP) control rooms and their effects on human reliability is criticalMapping Complexity Sources in Nuclear Power Plant Domains Understanding the sources of complexity of complexity leveraging network theory. INTRODUCTION The nuclear power industry in United States has declined

Cummings, Mary "Missy"

134

LARP Long Quadrupole Design  

Microsoft Academic Search

A major milestone for the LHC Accelerator Research Program (LARP) is the test, by the end of 2009, of two 4 m-long quadrupole magnets (LQ) wound with Nb3Sn conductor. The goal of these magnets is to be a proof of principle that Nb3Sn is a viable technology for a possible LHC luminosity upgrade. The design of the LQ is based

G. Ambrosio; N. Andreev; M. Anerella; E. Barzi; R. Bossert; S. Caspi; G. Chlachidize; D. Dietderich; S. Feher; H. Felice; P. Ferracin; A. Ghosh; R. Hafalia; R. Hannaford; V. V. Kashikhin; J. Kerby; M. Lamm; A. Lietzke; A. McInturff; J. Muratore; F. Nobrega; I. Novitsky; G. L. Sabbi; J. Schmalzle; M. Tartaglia; D. Turrioni; P. Wanderer; G. Whitson; A. V. Zlobin

2008-01-01

135

Dynamic use of geoscience information to develop scientific understanding for a nuclear waste repository  

SciTech Connect

The development and safety evaluation of a nuclear waste geologic repository require a proper scientific understanding of the site response. Such scientific understanding depends on information from a number of geoscience disciplines, including geology, geophysics, geochemistry, geomechanics and hydrogeology. The information comes in four stages: (1) general regional survey data base, (2) surface-based testing, (3) exploratory shaft testing, and (4) repository construction and evaluation. A discussion is given on the dynamic use of the information through the different stages. We point out the need for abstracting, deriving and updating a quantitative spatial and process model (QSPM) to develop a scientific understanding of site responses as a crucial element in the dynamic procedure. 2 figs.

Cook, N.G.W.; Tsang, C.F.

1990-01-01

136

Understanding the Nuclear Structure of ^8Li with a Radioactive Nuclear Beam  

NASA Astrophysics Data System (ADS)

^8Li is one of many unstable nuclei not abundant in nature. The purpose of this experiment was to determine whether ^8Li has a uniform nuclear mass density. A nonuniform mass distribution often signifies the presence of a halo, which affects reaction properties. A beam of ^8Li collided with a ^208Pb target and fused to excited ^216At^* . It decayed by neutron evaporation due to its high energy and angular momentum. At the studied beam energies of 36 -- 42 MeV, ^211At and ^212At were formed. ^212At ended in both its ground and metastable states. ^211At radioactively decayed with alpha emissions of 6.0 and 7.5 MeV, while ^212At decayed with alpha emissions of 7.6 and 7.8 MeV. Cross sections were calculated accounting for beam structure. The amount of metastable ^212At formed increases with energy, due to the higher initial angular momentum. The total cross sections were found to be about 100 millibarns lower than predicted. This could be due to incomplete fusion of ^8Li and ^208Pb.

Guess, Carol J.; Deyoung, P. A.; Peaslee, G. F.; Aguilera, E. F.; Martãnez Quiroz, E.; Kolata, J. J.; Hinnefeld, J. D.

2004-10-01

137

Impact Hazard Mitigation: Understanding the Effects of Nuclear Explosive Outputs on Comets and Asteroids  

NASA Astrophysics Data System (ADS)

The NASA 2007 white paper "Near-Earth Object Survey and Deflection Analysis of Alternatives" affirms deflection as the safest and most effective means of potentially hazardous object (PHO) impact prevention. It also calls for further studies of object deflection. In principle, deflection of a PHO may be accomplished by using kinetic impactors, chemical explosives, gravity tractors, solar sails, or nuclear munitions. Of the sudden impulse options, nuclear munitions are by far the most efficient in terms of yield-per-unit-mass launched and are technically mature. However, there are still significant questions about the response of a comet or asteroid to a nuclear burst. Recent and ongoing observational and experimental work is revolutionizing our understanding of the physical and chemical properties of these bodies (e.g., Ryan (2000), Fujiwara et al. (2006), and Jedicke et al. (2006)). The combination of this improved understanding of small solar-system bodies combined with current state-of-the-art modeling and simulation capabilities, which have also improved dramatically in recent years, allow for a science-based, comprehensive study of PHO mitigation techniques. Here we present an examination of the effects of radiation from a nuclear explosion on potentially hazardous asteroids and comets through Monte Carlo N-Particle code (MCNP) simulation techniques. MCNP is a general-purpose particle transport code commonly used to model neutron, photon, and electron transport for medical physics, reactor design and safety, accelerator target and detector design, and a variety of other applications including modeling the propagation of epithermal neutrons through the Martian regolith (Prettyman 2002). It is a massively parallel code that can conduct simulations in 1-3 dimensions, complicated geometries, and with extremely powerful variance reduction techniques. It uses current nuclear cross section data, where available, and fills in the gaps with analytical models where data are not available. MCNP has undergone extensive verification and validation and is considered the gold-standard for particle transport. (Forrest B. Brown, et al., "MCNP Version 5," Trans. Am. Nucl. Soc., 87, 273, November 2002.) Additionally, a new simulation capability using MCNP has become available to this collaboration. The first results of this new capability will also be presented. In particular, we will show results of neutron and gamma-ray energy deposition and flux as a function of material depth, composition, density, geometry, and distance from the source (nuclear burst). We will also discuss the benefits and shortcomings of linear Monte Carlo. Finally, we will set the stage for the correct usage and limitations of these results in coupled radiation-hydrodynamic calculations (see Plesko et al, this conference).

Clement, R.

138

On quadrupole vibrations in nearly spherical nuclei  

NASA Astrophysics Data System (ADS)

A new understanding of low-lying quadrupole vibrations in nuclei is emerging through lifetime measurements performed with fast neutrons at the accelerator laboratory of the University of Kentucky in combination with high-sensitivity measurements with other probes. In the stable cadmium nuclei, which have long been considered to be the best examples of vibrational behavior, we find that many E2 transition probabilities are well below harmonic vibrator expectations, and the B(E2)s cannot be explained with calculations incorporating configuration mixing between vibrational phonon states and intruder excitations. These data place severe limits on the collective models, and it is suggested that the low-lying levels of the Cd isotopes may not be of vibrational origin. An additional example of an apparent quadrupole vibrational nucleus, 62Ni, is considered.

Yates, S. W.

2012-09-01

139

Impact hazard mitigation: understanding the effects of nuclear explosive outputs on comets and asteroids  

SciTech Connect

The NASA 2007 white paper ''Near-Earth Object Survey and Deflection Analysis of Alternatives'' affirms deflection as the safest and most effective means of potentially hazardous object (PHO) impact prevention. It also calls for further studies of object deflection. In principle, deflection of a PHO may be accomplished by using kinetic impactors, chemical explosives, gravity tractors, solar sails, or nuclear munitions. Of the sudden impulse options, nuclear munitions are by far the most efficient in terms of yield-per-unit-mass launched and are technically mature. However, there are still significant questions about the response of a comet or asteroid to a nuclear burst. Recent and ongoing observational and experimental work is revolutionizing our understanding of the physical and chemical properties of these bodies (e.g ., Ryan (2000) Fujiwara et al. (2006), and Jedicke et al. (2006)). The combination of this improved understanding of small solar-system bodies combined with current state-of-the-art modeling and simulation capabilities, which have also improved dramatically in recent years, allow for a science-based, comprehensive study of PHO mitigation techniques. Here we present an examination of the effects of radiation from a nuclear explosion on potentially hazardous asteroids and comets through Monte Carlo N-Particle code (MCNP) simulation techniques. MCNP is a general-purpose particle transport code commonly used to model neutron, photon, and electron transport for medical physics reactor design and safety, accelerator target and detector design, and a variety of other applications including modeling the propagation of epithermal neutrons through the Martian regolith (Prettyman 2002). It is a massively parallel code that can conduct simulations in 1-3 dimensions, complicated geometries, and with extremely powerful variance reduction techniques. It uses current nuclear cross section data, where available, and fills in the gaps with analytical models where data are not available. MCNP has undergone extensive verification and validation and is considered the gold-standard for particle transport. (Forrest B. Brown, et al., ''MCNP Version 5,'' Trans. Am. Nucl. Soc., 87, 273, November 2002.) Additionally, a new simulation capability using MCNP has become available to this collaboration. The first results of this new capability will also be presented.

Clement, Ralph R C [Los Alamos National Laboratory; Plesko, Catherine S [Los Alamos National Laboratory; Bradley, Paul A [Los Alamos National Laboratory; Conlon, Leann M [Los Alamos National Laboratory

2009-01-01

140

Development of electrostatic quadrupoles for heavy ion fusion  

SciTech Connect

High-voltage electrostatic quadrupoles are used for focusing ion beams at low energies in the induction linac approach to heavy ion driven inertial confinement fusion for the production of electrical power. The transportable beam line charge density depends linearly on the operating voltage of the quadrupoles, so an experimental program was conducted to find the voltage breakdown dependence on the overall size of the quadrupoles which would then allow determination of the best geometry and operating voltage. The quadrupole electrodes are usually stainless steel cylinders with hemispherical end caps, mounted on stainless steel end plates. The end plates are precisely positioned with respect to each other and the vacuum chamber with alumina insulators with shielded triple points. It is advantageous for beam transport to employ an array of multiple beams for which a rather large number of interdigitated electrodes forms an array of quadrupoles. The tradeoffs between very large numbers of small channels and a smaller number of large channels, and the dependence of the choice on the voltage breakdown dependence is discussed. With present understanding, the optimum is about 100 beamlets focused with quadrupoles which have a beam aperture radius of about 2.3 cm and are operated with about 150 kV between electrodes.

Faltens, A.; Seidl, P. [Lawrence Berkeley National Lab., CA (United States)

1996-12-31

141

Microstructural Examination to Aid in Understanding Friction Bonding Fabrication Technique for Monolithic Nuclear Fuel  

SciTech Connect

Monolithic nuclear fuel is currently being developed for use in research reactors, and friction bonding (FB) is a technique being developed to help in this fuel’s fabrication. Since both FB and monolithic fuel are new concepts, research is needed to understand the impact of varying FB fabrication parameters on fuel plate characteristics. This thesis research provides insight into the FB process and its application to the monolithic fuel design by recognizing and understanding the microstructural effects of varying fabrication parameters (a) FB tool load, and (b) FB tool face alloy. These two fabrication parameters help drive material temperature during fabrication, and thus the material properties, bond strength, and possible formation of interface reaction layers. This study analyzed temperatures and tool loads measured during those FB processes and examined microstructural characteristics of materials and bonds in samples taken from the resulting fuel plates. This study shows that higher tool load increases aluminum plasticization and forging during FB, and that the tool face alloy helps determine the tool’s heat extraction efficacy. The study concludes that successful aluminum bonds can be attained in fuel plates using a wide range of FB tool loads. The range of tool loads yielding successful uranium-aluminum bonding was not established, but it was demonstrated that such bonding can be attained with FB tool load of 48,900 N (11,000 lbf) when using a FB tool faced with a tungsten alloy. This tool successfully performed FB, and with better results than tools faced with other materials. Results of this study correlate well with results reported for similar aluminum bonding techniques. This study’s results also provide support and validation for other nuclear fuel development studies and conclusions. Recommendations are offered for further research.

Karen L. Shropshire

2008-04-01

142

The determination of deuterium atom coordinates and nuclear quadrupole interactions in lanthanum nicotinate dihydrate crystals by Nd3+-deuterium double resonance  

Microsoft Academic Search

We have obtained the ENDOR (electron nuclear double resonance) spectra of the four deuterons of the two D2O molecules coordinated to Nd3+ dilutely substituted for La3+ in La2(C5H4NCO2)6 (D2O4)4 (dimeric lanthanum nicotinate dihydrate) molecules in single crystals. From the measurements of the values of the anisotropic magnetic hyperfine interactions between Nd3+ and the deuterons we have determined the coordinates of

Clyde A. Hutchison; Thomas E. Orlowski

1980-01-01

143

The determination of deuterium atom coordinates and nuclear quadrupole interactions in lanthanum nicotinate dihydrate crystals by Nd3+–deuterium double resonance  

Microsoft Academic Search

We have obtained the ENDOR (electron nuclear double resonance) spectra of the four deuterons of the two D2O molecules coordinated to Nd3+ dilutely substituted for La3+ in La2(C5H4NCO2)6 (D2O4)4 (dimeric lanthanum nicotinate dihydrate) molecules in single crystals. From the measurements of the values of the anisotropic magnetic hyperfine interactions between Nd3+ and the deuterons we have determined the coordinates of

Clyde A. Hutchison Jr; Thomas E. Orlowski

1980-01-01

144

Sodium-23 and potassium-39 nuclear magnetic resonance relaxation in eye lens. Examples of quadrupole ion magnetic relaxation in a crowded protein environment.  

PubMed Central

Single and multiple quantum nuclear magnetic resonance (NMR) spectroscopic techniques were used to investigate the motional dynamics of sodium and potassium ions in concentrated protein solution, represented in this study by cortical and nuclear bovine lens tissue homogenates. Both ions displayed homogeneous biexponential magnetic relaxation behavior. Furthermore, the NMR relaxation behavior of these ions in lens homogenates was consistent either with a model that assumed the occurrence of two predominant ionic populations, "free" and "bound," in fast exchange with each other or with a model that assumed an asymmetric Gaussian distribution of correlation times. Regardless of the model employed, both ions were found to occur in a predominantly "free" or "unbound" rapidly reorienting state. The fraction of "bound" 23Na+, assuming a discrete two-site model, was approximately 0.006 and 0.017 for cortical and nuclear homogenates, respectively. Corresponding values for 39K+ were 0.003 and 0.007, respectively. Estimated values for the fraction of "bound" 23Na+ or 39K+ obtained from the distribution model (tau C greater than omega L-1) were less than or equal to 0.05 for all cases examined. The correlation times of the "bound" ions, derived using either a two-site or distribution model, yielded values that were at least one order of magnitude smaller than the reorientational motion of the constituent lens proteins. This observation implies that the apparent correlation time for ion binding is dominated by processes other than protein reorientational motion, most likely fast exchange between "free" and "bound" environments. The results of NMR visibility studies were consistent with the above findings, in agreement with other studies performed by non-NMR methods. These studies, in combination with those presented in the literature, suggest that the most likely role for sodium and potassium ions in the lens appears to be the regulation of cell volume by affecting the intralenticular water chemical potential. Images FIGURE 4 PMID:1600073

Stevens, A; Paschalis, P; Schleich, T

1992-01-01

145

Simultaneous quadrupole and octupole shape phase transitions in Thorium  

E-print Network

The evolution of quadrupole and octupole shapes in Th isotopes is studied in the framework of nuclear Density Functional Theory. Constrained energy maps and observables calculated with microscopic collective Hamiltonians indicate the occurrence of a simultaneous quantum shape phase transition between spherical and quadrupole-deformed prolate shapes, and between non-octupole and octupole-deformed shapes, as functions of the neutron number. The nucleus $^{224}$Th is closest to the critical point of a double phase transition. A microscopic mechanism of this phenomenon is discussed in terms of the evolution of single-nucleon orbitals with deformation.

Z. P. Li; B. Y. Song; J. M. Yao; D. Vretenar; J. Meng

2013-09-11

146

F-doping dependence of 75As nuclear quadrupole resonance frequency in LaFeAs(O1-xFx)  

NASA Astrophysics Data System (ADS)

We report the F-doping dependence of 75As nuclear quadruple resonance frequency (75?Q) in the iron-oxypnictide LaFeAs(O1-xFx) (x = 0, 0.07, 0.08, 0.11 and 0.14). It was revealed that 75?Q becomes larger with increasing x up to 0.14. From point charge calculations, we found that experimental F-doping dependence of 75?Q cannot be accounted for by the effect of surrounding ions. Therefore, the on-site charge distribution at the 75As site modified by the hybridization between As-4p and Fe-3d orbitals gives dominant contribution to 75?Q in LaFeAs(O1-xFx).

Kitagawa, S.; Nakai, Y.; Iye, T.; Ishida, K.; Kamihara, Y.; Hirano, M.; Hosono, H.

2010-12-01

147

The quadrupole interaction of 100 Rh in various intermetallic compounds of palladium  

Microsoft Academic Search

The nuclear quadrupole interaction of the 75 keV excited state of100Rh in the ordered intermetallic compounds PdHg, PdPb2 PdSb and PdTe was measured. Using an estimate for the nuclear quadrupole moment of the 75 keV state in100Rh and point ion lattice sums for the lattice electric field gradient (EFG) at the Rh site, the electronic contributionVzzel to the total EFG

R. Vianden; E. N. Kaufmann; R. A. Naumann; G. Schmidt

1979-01-01

148

The quadrupole interaction of100Rh in various intermetallic compounds of palladium  

Microsoft Academic Search

The nuclear quadrupole interaction of the 75 keV excited state of100Rh in the ordered intermetallic compounds PdHg, PdPb2 PdSb and PdTe was measured. Using an estimate for the nuclear quadrupole moment of the 75 keV state in100Rh and point ion lattice sums for the lattice electric field gradient (EFG) at the Rh site, the electronic contribution V {zz\\/el} to the

R. Vianden; E. N. Kaufmann; R. A. Naumann; G. Schmidt

1979-01-01

149

Hydrogen Interaction with Metal Halides: the Nuclear Quadrupole Coupling Constant of Gold in the {p}{-H}_2{-AuCl} Complex and Trends in the Other Hydrogen-Coinage Metal Halide Interactions  

NASA Astrophysics Data System (ADS)

The rotational spectrum of p-H_2-AuCl has been measured using a laser ablation equipped FTMW cavity spectrometer. The predicted structure, using a 60 electron core potential and an aug-cc-pVQZ at the MP2 level of theory, shows that H_2 has an r_e = 0.91Å. A predicted value for the eQq(?_{aa}) of gold required a semi-empirical method using the results of previous AuCl complexes in the gas phase. Transitions have been measured across multiple J levels, and have been used to determine the rotational constants, centrifugal distortion constants, and nuclear quadrupole coupling constants of multiple isotopologues. The o-H_2-AuCl has also been observed. While the monomer value of the eQq of ^{197}Au was determined to be 9.63112(13) MHz in ^{197}Au^{35}Cl, we observed a significant change in the eQq of ^{197}Au in p-H_2-^{197}Au^{35}Cl to a value of -817.9983(36) MHz [0.02728556(12) cm^{-1}], giving rise to a Au hyperfine component splittings of approximately 220 MHz [0.007 cm^{-1}] and suggesting a change in electronic structure with the interaction of H_2. We will present a summary of the hydrogen-coinage metal halide talks given at this conference, including trends in eQq and hydrogen metal halide dissociation energies. D. Figgen, G. Rauhut, M. Dolh, H. Stoll J. Chem. Phys. 311(2005) 227. K. A. Peterson, C. Puzzarini, Theor. Chem. Acc. 114 (2005) 283. C. J. Evans, C. L. Gerry J. Mol. Spectrosc. 203 (2000) 105.

Obenchain, Daniel A.; Grubbs, G. S. Grubbs, Ii; Pickett, Herbert M.; Novick, Stewart E.

2013-06-01

150

Current Understanding and Remaining Challenges in Modeling Long-Term Degradation of Borosilicate Nuclear Waste Glasses  

SciTech Connect

Chemical durability is not a single material property that can be uniquely measured. Instead it is the response to a host of coupled material and environmental processes whose rates are estimated by a combination of theory, experiment, and modeling. High-level nuclear waste (HLW) glass is perhaps the most studied of any material yet there remain significant technical gaps regarding their chemical durability. The phenomena affecting the long-term performance of HLW glasses in their disposal environment include surface reactions, transport properties to and from the reacting glass surface, and ion exchange between the solid glass and the surrounding solution and alteration products. The rates of these processes are strongly influenced and are coupled through the solution chemistry, which is in turn influenced by the reacting glass and also by reaction with the near-field materials and precipitation of alteration products. Therefore, those processes must be understood sufficiently well to estimate or bound the performance of HLW glass in its disposal environment over geologic time-scales. This article summarizes the current state of understanding of surface reactions, transport properties, and ion exchange along with the near-field materials and alteration products influences on solution chemistry and glass reaction rates. Also summarized are the remaining technical gaps along with recommended approaches to fill those technical gaps.

Vienna, John D.; Ryan, Joseph V.; Gin, Stephane; Inagaki, Yaohiro

2013-12-01

151

Understanding Nuclear Weapons and Arms Control: A Guide to the Issues. New Edition.  

ERIC Educational Resources Information Center

Intended for secondary and college level students and teachers, this guide discusses the nuclear arms control issue. There are four sections. Section I discusses U.S. nuclear strategy from 1945 to the present, strategic nuclear weapons competition between the United States and the Union of Soviet Socialist Republics (U.S.S.R.), U.S.…

Mayers, Teena

152

Toward a global understanding of nuclear energy and radioactive waste management  

Microsoft Academic Search

Within the past two decades important questions have emerged relative to the increased use of nuclear energy world?wide and to the need to store high?level radioactive waste from nuclear energy plants. Because students in today's classrooms will become future decision makers and caretakers of both nuclear power plants and radioactive waste repositories, they will be faced with these questions. This

Richard R. Powell; Michael G. Robinson; William Pankratius

1994-01-01

153

Topology of the interactions pattern in pharmaceutically relevant polymorphs of methylxanthines (caffeine, theobromine, and theophiline): combined experimental (¹H-¹?N nuclear quadrupole double resonance) and computational (DFT and Hirshfeld-based) study.  

PubMed

Three anhydrous methylxanthines: caffeine (1,3,7-trimethylxanthine; 1,3,7-trimethyl-1H-purine-2,6-(3H,7H)-dione) and its two metabolites theophylline (1,3-dimethylxanthine; 1,3-dimethyl-7H-purine-2,6-dione) and theobromine (3,7-dimethyl-xanthine; 3,7-dimethyl-7H-purine-2,6-dione), which reveal multifaceted therapeutic potential, have been studied experimentally in solid state by (1)H-(14)N NMR-NQR (nuclear magnetic resonance-nuclear quadrupole resonance) double resonance (NQDR). For each compound the complete NQR spectrum consisting of 12 lines was recorded. The multiplicity of NQR lines indicates the presence of a stable ? form of anhydrous caffeine at 233 K and stable form II of anhydrous theobromine at 213 K. The assignment of signals detected in NQR experiment to particular nitrogen atoms was made on the basis of quantum chemistry calculations performed for monomer, cluster, and solid at the DFT/GGA/BLYP/DPD level. The shifts due to crystal packing interactions were evaluated, and the multiplets detected by NQR were assigned to N(9) in theobromine and N(1) and N(9) in caffeine. The ordering theobromine > theophylline > caffeine site and theophylline < theobromine < caffeine according to increasing electric field gradient (EFG) at the N(1) and N(7) sites, respectively, reflects the changes in biological activity profile of compounds from the methylxanthines series (different pharmacological effects). This difference is elucidated on the basis of the ability to form intra- and intermolecular interactions (hydrogen bonds and ?···? stacking interactions). The introduction of methyl groups to xanthine restricts the ability of nitrogen atoms to participate in strong hydrogen bonds; as a result, the dominating effect shifts from hydrogen bond (theobromine) to ?···? stacking (caffeine). Substantial differences in the intermolecular interactions in stable forms of methylxanthines differing in methylation (site or number) were analyzed within the Hirshfeld surface-based approach. The analysis of local environment of the nitrogen nucleus permitted drawing some conclusions on the nature of the interactions required for effective processes of recognition and binding of a given methylxanthine to A1-A(2A) receptor (target for caffeine in the brain). Although the interactions responsible for linking neighboring methylxanthines molecules in crystals and methylxanthines with targets in the human organism can differ significantly, the knowledge of the topology of interactions provides reliable preliminary information about the nature of this binding. PMID:25184363

Latosi?ska, Jolanta Natalia; Latosi?ska, Magdalena; Olejniczak, Grzegorz A; Seliger, Janez; Žagar, Veselko

2014-09-22

154

LCLS Undulator Quadrupole Fiducialization Plan  

SciTech Connect

This note presents the fiducialization plan for the LCLS undulator quadrupoles. The note begins by summarizing the requirements for the fiducialization. A discussion of the measurement equipment is presented, followed by the methods used to perform the fiducialization and check the results. This is followed by the detailed fiducialization plan in which each step is enumerated. Finally, the measurement results and data storage formats are presented. The LCLS is made up of 33 assemblies consisting of an undulator, quadrupole, beam finder wire, and other components mounted on a girder. The components must be mounted in such a way that the beam passes down the axis of each component. In this note, we describe how the ideal beam axis is related to tooling balls on the quadrupole. This step, called fiducialization, is necessary because the ideal beam axis is determined magnetically, whereas tangible objects must be used to locate the quadrupole. The note begins with the list of fiducialization requirements. The laboratory in which the work will be performed and the relevant equipment is then briefly described. This is followed by a discussion of the methods used to perform the fiducialization and the methods used to check the results. A detailed fiducialization plan is presented in which all the steps of fiducialization are enumerated. A discussion of the resulting data files and directory structure concludes the note.

Wolf, Zachary; Levashov, Michael; Lundahl, Eric; Reese, Ed; LeCocq, Catherine; Ruland, Robert; /SLAC; ,

2010-11-24

155

Nuclear {sup 111}Cd probes detect a hidden symmetry change at the {gamma} {sup {yields} {alpha}} transition in cerium considered isostructural for 60 years  

SciTech Connect

We use the time-differential perturbed angular correlation technique to study nuclear electric quadrupole hyperfine interactions of probe {sup 111}Cd nuclei in cerium lattice sites at room temperature under pressures up to 8 GPa. We have found that the well known {gamma} {sup {yields} {alpha}} phase transition in cerium is not isostructural. In {alpha}-Ce, the probe {sup 111}Cd nuclei reveal a quadrupole electron charge density component that is absent in {gamma}-Ce. The hidden spacial structure of electronic quadrupoles in {alpha}-Ce is triple-q antiferroquadrupolar, as was suggested in [14]. We relate our findings to the current understanding of the {gamma} {sup {yields} {alpha}} phase transition and also report on nuclear quadrupole interactions in other high-pressure phases of cerium: {alpha}'' (C2/m space symmetry) and {alpha}' ({alpha}-U structure).

Tsvyashchenko, A. V., E-mail: tsvyash@hppi.troitsk.r [Russian Academy of Sciences, Vereshchagin Institute for High Pressure Physics (Russian Federation); Nikolaev, A. V. [Lomonosov Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation); Velichkov, A. I.; Salamatin, A. V. [Joint Institute for Nuclear Research (Russian Federation); Fomicheva, L. N. [Russian Academy of Sciences, Vereshchagin Institute for High Pressure Physics (Russian Federation); Ryasny, G. K.; Sorokin, A. A. [Lomonosov Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation); Kochetov, O. I. [Joint Institute for Nuclear Research (Russian Federation); Budzynski, M. [Curie-Sklodowska University, Institute of Physics (Poland)

2010-10-15

156

How genomic studies have improved our understanding of the mechanisms of transcriptional regulation by NR5A nuclear receptors.  

PubMed

SF-1 and LRH-1 are transcription factors that belong to the NR5A family of nuclear receptors that both have an essential role during development. Recent studies at the genome-wide scale have enabled the characterization of the cistrome and transcriptome regulated by SF-1 and LRH-1 in different cell lines and tissues. Those studies have allowed us to make a significant leap forward in our understanding of the mechanisms of transcriptional regulation of NR5A nuclear receptors in stem cells and cancer. PMID:25449416

Ruggiero, Carmen; Doghman, Mabrouka; Lalli, Enzo

2014-10-31

157

RADIATION RESISTANT HTS QUADRUPOLES FOR RIA.  

SciTech Connect

Extremely high radiation, levels with accumulated doses comparable to those in nuclear reactors than in accelerators, and very high heat loads ({approx}15 kw) make the quadrupole magnets in the fragment separator one of the most challenging elements of the proposed Rare Isotope Accelerator (RIA). Removing large heat loads, protecting the superconducting coils against quenching, the long term survivability of magnet components, and in particular, insulation that can retain its functionality in such a harsh environment, are the major challenges associated with such magnets. A magnet design based on commercially available high temperature superconductor (HTS) and stainless steel tape insulation has been developed. HTS will efficiently remove these large heat loads and stainless steel can tolerate these large radiation doses. Construction of a model magnet has been started with several coils already built and tested. This paper presents the basic magnet design, results of the coil tests, the status and the future plans. In addition, preliminary results of radiation calculations are also presented.

GUPTA,R.; ANERELLA,M.; HARRISON,M.; ET AL.

2004-10-03

158

Nuclear Cardiology Objectives Understand the principles of myocardial perfusion and blood flow, factors  

E-print Network

and blood flow, factors determining flow, coronary flow regulation, vasoreactivity, coronary flow reserve, and technique · Understand the difference between a direct and indirect test of coronary flow reserve, regional flow differences, and flow variability. · Understand the principles of radioactivity, radioactive

Ford, James

159

Microlensing modulation by quadrupole variation  

E-print Network

We investigate microlensing in the case where the lens is considered as an extended object. We use a multipolar expansion of the lens potential and show that the time-varying nature of the quadrupole contribution allows to separate it from the mass and spin contributions and leads to specific modulations of the amplification signal. As example we study the case of binary system lenses in our galaxy. The modulation is observable if the rotation period of the system is smaller than the time over which the amplification is significant and if the impact parameter of the passing light ray is sufficiently close to the Einstein radius so that the amplification is large. Observations of this modulation can reveal important information on the quadrupole and thus on the gravitational radiation emitted by the binary lens. Even if not observed directly, because of their importance the quadrupole modulation has to be included in the error budget for high magnification ($\\mu\\leq7$) microlensing events.

Florian Dubath; Maria Alice Gasparini; Ruth Durrer

2007-01-11

160

Measurements of spectroscopic quadrupole moments of neutron-deficient Au isotopes with quadrupole-interaction-resolved NMR-ON  

NASA Astrophysics Data System (ADS)

We report on measurements of quadrupole-interaction-resolved nuclear magnetic resonance on oriented nuclei ( QI-NMR-ON) of{3}/{2}+193Au (T {1}/{2} = 17.5 h)and{3}/{2}+195Au(T {1}/{2}=183 d) hcp-Co. The results for the magnetic and electric hyperfine splittings are: 193Au: ?M = 67.72(2) MHz; ?Q = - 15.69(4) MHz; 195Au; ?M = 71.65(1) MHz; ?Q = - 14.34(2) MHz. Taking into account hyperfine anomalies, the magnetic moments are deduced to be: ?( 193Au) = 0.1396(6) ? N; ?( 195Au) = 0.1487(6) ? N. With the known quadrupole moment of 193Au, Q = + 0.664(20), b, the electric field gradient of Au in hcp-Co is deduced to be eq = - 0.977(29) × 10 17V/ cm2, with which Q( 195Au) = + 0.607(18) b is obtained for the spectroscopic quadrupole moment of 195Au. In addition, the experimentally known quadrupole splitting frequencies of 186Au, 198Au and 199Au in hcp-Co can be reinterpreted, giving the results: Q( 186Au) = + 3.14(16) b; Q( 198Au) = + 0.640(19) b; Q( 199Au) = + 0.510(16) b.

Hinfurtner, B.; König, C.; Hagn, E.; Zech, E.; Eder, R.; Forkel, D.; Isolde Collaboration

1993-09-01

161

A Science-Based Approach to Understanding Waste Form Durability in Open and Closed Nuclear Fuel Cycles  

SciTech Connect

There are two compelling reasons for understanding source term and near-field processes in a radioactive waste geologic repository. First, almost all of the radioactivity is initially in the waste form, mainly in the spent nuclear fuel (SNF) or nuclear waste glass. Second, over long periods, after the engineered barriers are degraded, the waste form is a primary control on the release of radioactivity. Thus, it is essential to know the physical and chemical state of the waste form after hundreds of thousands of years. The United States Department of Energy's Yucca Mountain Repository Program has initiated a long-term program to develop a basic understanding of the fundamental mechanisms of radionuclide release and a quantification of the release as repository conditions evolve over time. Specifically, the research program addresses four critical areas: a) SNF dissolution mechanisms and rates; b) formation and properties of U{sup 6+}- secondary phases; c) waste form-waste package interactions in the near-field; and d) integration of in-package chemical and physical processes. The ultimate goal is to integrate the scientific results into a larger scale model of source term and near-field processes. This integrated model will be used to provide a basis for understanding the behavior of the source term over long time periods (greater than 10{sup 5} years). Such a fundamental and integrated experimental and modeling approach to source term processes can also be readily applied to development of advanced waste forms as part of a closed nuclear fuel cycle. Specifically, a fundamental understanding of candidate waste form materials stability in high temperature/high radiation environments and near-field geochemical/hydrologic processes could enable development of advanced waste forms 'tailored' to specific geologic settings. (authors)

Peters, M.T. [Applied Science and Technology, Argonne National Laboratory, 9700 South Cass Ave., Argonne, IL, 60439 (United States); Ewing, R.C. [Department of Geological Sciences, The University of Michigan, 2534 C.C. Little Bldg., 1100 N. University, Ann Arbor, MI, 48109-1005 (United States)

2007-07-01

162

A science-based approach to understanding waste form durability in open and closed nuclear fuel cycles  

NASA Astrophysics Data System (ADS)

There are two compelling reasons for understanding source term and near-field processes in a radioactive waste geologic repository. First, almost all of the radioactivity is initially in the waste form, mainly in the spent nuclear fuel (SNF) or nuclear waste glass. Second, over long periods, after the engineered barriers are degraded, the waste form is a primary control on the release of radioactivity. Thus, it is essential to know the physical and chemical state of the waste form after hundreds of thousands of years. The United States Department of Energy's Yucca Mountain Repository Program has initiated a long-term program to develop a basic understanding of the fundamental mechanisms of radionuclide release and a quantification of the release as repository conditions evolve over time. Specifically, the research program addresses four critical areas: (a) SNF dissolution mechanisms and rates; (b) formation and properties of U 6+-secondary phases; (c) waste form-waste package interactions in the near-field; and (d) integration of in-package chemical and physical processes. The ultimate goal is to integrate the scientific results into a larger scale model of source term and near-field processes. This integrated model will be used to provide a basis for understanding the behaviour of the source term over long time periods (greater than 10 5 years). Such a fundamental and integrated experimental and modelling approach to source term processes can also be readily applied to development of advanced waste forms as part of a closed nuclear fuel cycle. Specifically, a fundamental understanding of candidate waste form materials stability in high temperature/high radiation environments and near-field geochemical/hydrologic processes could enable development of advanced waste forms 'tailored' to specific geologic settings.

Peters, M. T.; Ewing, R. C.

2007-05-01

163

Laced permanent magnet quadrupole drift tube magnets  

SciTech Connect

Twenty-three laced permanent magnet quadrupole drift tube magnets have been constructed, tested, and installed in the SuperHILAC heavy ion linear accelerator at LBL, marking the first accelerator use of this new type of quadrupole. The magnets consist of conventional tape-wound quadrupole electromagnets, using iron pole-pieces, with permanent magnet material (samarium cobalt) inserted between the poles to reduce the effects of saturation. The iron is preloaded with magnetic flux generated by the permanent magnet material, resulting in an asymmetrical saturation curve. Since the polarity of the individual quadrupole magnets in a drift tube linac is never reversed, we can take advantage of this asymmetrical saturation to provide about 20% greater focusing strength than is available with conventional quadrupoles, while replacing the vanadium permendur poletips with iron poletips. Comparisons between these magnets and conventional tape-wound quadrupoles will be presented. 3 refs., 5 figs.

Feinberg, B.; Behrsing, G.U.; Halbach, K.; Marks, J.S.; Morrison, M.E.; Nelson, D.H.

1989-03-01

164

Laced permanent magnet quadrupole drift tube magnets  

Microsoft Academic Search

Twenty-three laced permanent magnet quadrupole drift tube magnets have been constructed, tested, and installed in the SuperHILAC heavy ion linear accelerator at LBL (Lawrence Berkeley Laboratory), marking the first accelerator use of this new type of quadrupole. The magnets consist of conventional tape-wound quadrupole electromagnets, using iron pole-pieces, with permanent magnet material (samarium cobalt) inserted between the poles to reduce

B. Feinberg; G. U. Behrsing; K. Halbach; J. S. Marks; M. E. Morrison; D. H. Nelson

1989-01-01

165

A coherent understanding of low-energy nuclear recoils in liquid xenon  

SciTech Connect

Liquid xenon detectors such as XENON10 and XENON100 obtain a significant fraction of their sensitivity to light (?<10 GeV) particle dark matter by looking for nuclear recoils of only a few keV, just above the detector threshold. Yet in this energy regime a correct treatment of the detector threshold and resolution remains unclear. The energy dependence of the scintillation yield of liquid xenon for nuclear recoils also bears heavily on detector sensitivity, yet numerous measurements have not succeeded in obtaining concordant results. In this article we show that the ratio of detected ionization to scintillation can be leveraged to constrain the scintillation yield. We also present a rigorous treatment of liquid xenon detector threshold and energy resolution. Notably, the effective energy resolution differs significantly from a simple Poisson distribution. We conclude with a calculation of dark matter exclusion limits, and show that existing data from liquid xenon detectors strongly constrain recent interpretations of light dark matter.

Sorensen, Peter, E-mail: pfs@llnl.gov [Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, CA 94550 (United States)

2010-09-01

166

First principles calculations of nucleon and pion form factors: understanding the building blocks of nuclear matter from lattice QCD  

SciTech Connect

Lattice QCD is an essential complement to the current and anticipated DOE-supported experimental program in hadronic physics. In this poster we address several key questions central to our understanding of the building blocks of nuclear matter, nucleons and pions. Firstly, we describe progress at computing the electromagnetic form factors of the nucleon, describing the distribution of charge and current, before considering the role played by the strange quarks. We then describe the study of transition form factors to the Delta resonance. Finally, we present recent work to determine the pion form factor, complementary to the current JLab experimental determination and providing insight into the approach to asymptotic freedom.

Constantia Alexandrou; Bojan Bistrovic; Robert Edwards; P de Forcrand; George Fleming; Philipp Haegler; John Negele; Konstantinos Orginos; Andrew Pochinsky; Dru Renner; David Richards; Wolfram Schroers; Antonios Tsapalis

2005-10-01

167

A coherent understanding of low-energy nuclear recoils in liquid xenon  

E-print Network

Liquid xenon detectors such as XENON10 and XENON100 obtain a significant fraction of their sensitivity to light (xenon for nuclear recoils also bears heavily on detector sensitivity, yet numerous measurements have not succeeded in obtaining concordant results. In this article we show that the ratio of detected ionization to scintillation can be leveraged to constrain the scintillation yield. We also present a rigorous treatment of liquid xenon detector threshold and energy resolution. Notably, the effective energy resolution differs significantly from a simple Poisson distribution. We conclude with a calculation of dark matter exclusion limits, and show that existing data from liquid xenon detectors strongly constrain recent interpretations of light dark matter.

Peter Sorensen

2010-09-07

168

A Vibrating Wire System For Quadrupole Fiducialization  

SciTech Connect

A vibrating wire system is being developed to fiducialize the quadrupoles between undulator segments in the LCLS. This note provides a detailed analysis of the system. The LCLS will have quadrupoles between the undulator segments to keep the electron beam focused. If the quadrupoles are not centered on the beam axis, the beam will receive transverse kicks, causing it to deviate from the undulator axis. Beam based alignment will be used to move the quadrupoles onto a straight line, but an initial, conventional alignment must place the quadrupole centers on a straight line to 100 {micro}m. In the fiducialization step of the initial alignment, the position of the center of the quadrupole is measured relative to tooling balls on the outside of the quadrupole. The alignment crews then use the tooling balls to place the magnet in the tunnel. The required error on the location of the quadrupole center relative to the tooling balls must be less than 25 {micro}m. In this note, we analyze a system under construction for the quadrupole fiducialization. The system uses the vibrating wire technique to position a wire onto the quadrupole magnetic axis. The wire position is then related to tooling balls using wire position detectors. The tooling balls on the wire position detectors are finally related to tooling balls on the quadrupole to perform the fiducialization. The total 25 {micro}m fiducialization error must be divided between these three steps. The wire must be positioned onto the quadrupole magnetic axis to within 10 {micro}m, the wire position must be measured relative to tooling balls on the wire position detectors to within 15 {micro}m, and tooling balls on the wire position detectors must be related to tooling balls on the quadrupole to within 10 {micro}m. The techniques used in these three steps will be discussed. The note begins by discussing various quadrupole fiducialization techniques used in the past and discusses why the vibrating wire technique is our method of choice. We then give an overview of the measurement system showing how the vibrating wire is positioned onto the quadrupole axis, how the wire position detectors locate the wire relative to tooling balls without touching the wire, and how the tooling ball positions are all measured. The novel feature of this system is the vibrating wire which we discuss in depth. We analyze the wire dynamics and calculate the expected sensitivity of the system. The note should be an aid in debugging the system by providing calculations to compare measurements to.

Wolf, Zachary

2010-12-13

169

Lighthill quadrupole radiation in supersonic propeller acoustics  

Microsoft Academic Search

Sound generation by the Lighthill quadrupole is an important mechanism in the noise of supersonic and transonic propellers. Full numerical calculation of the quadrupole radiation, however, requires knowledge of the flow at all points exterior to the blades (involving transonic aerodynamics) and the evaluation of special functions. This paper describes how these difficulties may be largely avoided, using an asymptotic

N. Peake; D. G. Crighton

1991-01-01

170

Electrostatic quadrupoles for heavy-ion fusion  

SciTech Connect

Voltage-holding data for three quadrupole electrode sizes and inter-electrode spacings are reported. The dependence of the breakdown voltage on system size and its influence on the optimum quadrupole size for beam transport in a multiple beam array are discussed.

Seidl, P.; Faltens, A.

1993-05-01

171

Use of first order reversal curve measurements to understand Barkhausen noise emission in nuclear steel  

NASA Astrophysics Data System (ADS)

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

McCloy, J. S.; Ramuhalli, Pradeep; Henager, Charles, Jr.

2013-01-01

172

Dyson representation of the interacting boson model with pairing plus quadrupole pairing plus quadrupole-quadrupole forces  

SciTech Connect

With a usual choice of the effective nucleon-nucleon interactions consisting of a pairing force, a quadrupole pairing force, and a quadrupole-quadrupole force, the microscopic approach, as described in our previous work, based on the Dyson boson expansion and based on the so-called modified Jancovici-Schiff substitution is followed to obtain a set of eigenequations for determining the IBM bosons and to find the microscopic expressions of the coefficients appearing in the interaction terms of the IBM Hamiltonian. The results given in the present paper can be used directly in calculating the collective spectra of nuclei with identical valence nucleons outside closed shells.

Yang, T.S.; Liu, Y.; Tian, X.C.

1983-04-01

173

Understanding generalized inversions of nuclear magnetic resonance transverse relaxation time in porous media  

NASA Astrophysics Data System (ADS)

The nuclear magnetic resonance transverse relaxation time T2, measured using the Carr-Purcell-Meiboom-Gill (CPMG) experiment, is a powerful method for obtaining unique information on liquids confined in porous media. Furthermore, T2 provides structural information on the porous material itself and has many applications in petrophysics, biophysics, and chemical engineering. Robust interpretation of T2 distributions demands appropriate processing of the measured data since T2 is influenced by diffusion through magnetic field inhomogeneities occurring at the pore scale, caused by the liquid/solid susceptibility contrast. Previously, we introduced a generic model for the diffusion exponent of the form -ant_e^k (where n is the number and te the temporal separation of spin echoes, and a is a composite diffusion parameter) in order to distinguish the influence of relaxation and diffusion in CPMG data. Here, we improve the analysis by introducing an automatic search for the optimum power k that best describes the diffusion behavior. This automated method is more efficient than the manual trial-and-error grid search adopted previously, and avoids variability through subjective judgments of experimentalists. Although our method does not avoid the inherent assumption that the diffusion exponent depends on a single k value, we show through simulation and experiment that it is robust in measurements of heterogeneous systems that violate this assumption. In this way, we obtain quantitative T2 distributions from complicated porous structures and demonstrate the analysis with examples of ceramics used for filtration and catalysis, and limestone of relevance to the construction and petroleum industries.

Mitchell, J.; Chandrasekera, T. C.

2014-12-01

174

Toward Understanding the Effect of Nuclear Waste Glass Composition on Sulfur Solubility  

DOE PAGESBeta

The concentration of sulfur in nuclear waste glass melter feed must be maintained below the point where salt accumulates on the melt surface. The allowable concentrations may range from 0.37 to over 2.05 weight percent (of SO3 on a calcined oxide basis) depending on the composition of the melter feed and processing conditions. If the amount of sulfur exceeds the melt tolerance level, a molten salt will accumulate, which may upset melter operations and potentially shorten the useful life of the melter. At the Hanford site, relatively conservative limits have been placed on sulfur loading in melter feed, which in turn significantly increases the amount of glass that will be produced. Crucible-scale sulfur solubility data and scaled melter sulfur tolerance data have been collected on simulated Hanford waste glasses over the last 15 years. These data were compiled and analyzed. A model was developed to predict the solubility of SO3 in glass based on 252 simulated Hanford low-activity waste (LAW) glass compositions. This model represents the data well, accounting for over 85% of the variation in data, and was well validated. The model was also found to accurately predict the tolerance for sulfur in melter feed for 13 scaled melter tests of simulated LAW glasses. The model can be used to help estimate glass volumes and make informed decisions on process options. The model also gives quantitative estimates of component concentration effects on sulfur solubility. The components that most increase sulfur solubility are Li2O > V2O5> CaO ? P2O5 > Na2O ? B2O3 > K2O. The components that most decrease sulfur solubility are Cl > Cr2O3 > Al2O3 > ZrO2 ? SnO2 > Others ? SiO2. The order of component effects is similar to previous literature data, in most cases.

Vienna, John D. [Pacific Northwest National Laboratory; Kim, Dong-Sang [Pacific Northwest National Laboratory; Muller, I. S. [The Catholic University National Laboratory; Kruger, Albert A. [Department of Energy -- Ofice of River Protection; Piepel, Gregory F. [Pacific Northwest National Laboratory

2014-10-01

175

Understanding generalized inversions of nuclear magnetic resonance transverse relaxation time in porous media.  

PubMed

The nuclear magnetic resonance transverse relaxation time T2, measured using the Carr-Purcell-Meiboom-Gill (CPMG) experiment, is a powerful method for obtaining unique information on liquids confined in porous media. Furthermore, T2 provides structural information on the porous material itself and has many applications in petrophysics, biophysics, and chemical engineering. Robust interpretation of T2 distributions demands appropriate processing of the measured data since T2 is influenced by diffusion through magnetic field inhomogeneities occurring at the pore scale, caused by the liquid/solid susceptibility contrast. Previously, we introduced a generic model for the diffusion exponent of the form -ante(k) (where n is the number and te the temporal separation of spin echoes, and a is a composite diffusion parameter) in order to distinguish the influence of relaxation and diffusion in CPMG data. Here, we improve the analysis by introducing an automatic search for the optimum power k that best describes the diffusion behavior. This automated method is more efficient than the manual trial-and-error grid search adopted previously, and avoids variability through subjective judgments of experimentalists. Although our method does not avoid the inherent assumption that the diffusion exponent depends on a single k value, we show through simulation and experiment that it is robust in measurements of heterogeneous systems that violate this assumption. In this way, we obtain quantitative T2 distributions from complicated porous structures and demonstrate the analysis with examples of ceramics used for filtration and catalysis, and limestone of relevance to the construction and petroleum industries. PMID:25494741

Mitchell, J; Chandrasekera, T C

2014-12-14

176

Understanding fuel magnetization and mix using secondary nuclear reactions in magneto-inertial fusion.  

PubMed

Magnetizing the fuel in inertial confinement fusion relaxes ignition requirements by reducing thermal conductivity and changing the physics of burn product confinement. Diagnosing the level of fuel magnetization during burn is critical to understanding target performance in magneto-inertial fusion (MIF) implosions. In pure deuterium fusion plasma, 1.01 MeV tritons are emitted during deuterium-deuterium fusion and can undergo secondary deuterium-tritium reactions before exiting the fuel. Increasing the fuel magnetization elongates the path lengths through the fuel of some of the tritons, enhancing their probability of reaction. Based on this feature, a method to diagnose fuel magnetization using the ratio of overall deuterium-tritium to deuterium-deuterium neutron yields is developed. Analysis of anisotropies in the secondary neutron energy spectra further constrain the measurement. Secondary reactions also are shown to provide an upper bound for the volumetric fuel-pusher mix in MIF. The analysis is applied to recent MIF experiments [M. R. Gomez et al., Phys. Rev. Lett. 113, 155003 (2014)] on the Z Pulsed Power Facility, indicating that significant magnetic confinement of charged burn products was achieved and suggesting a relatively low-mix environment. Both of these are essential features of future ignition-scale MIF designs. PMID:25375715

Schmit, P F; Knapp, P F; Hansen, S B; Gomez, M R; Hahn, K D; Sinars, D B; Peterson, K J; Slutz, S A; Sefkow, A B; Awe, T J; Harding, E; Jennings, C A; Chandler, G A; Cooper, G W; Cuneo, M E; Geissel, M; Harvey-Thompson, A J; Herrmann, M C; Hess, M H; Johns, O; Lamppa, D C; Martin, M R; McBride, R D; Porter, J L; Robertson, G K; Rochau, G A; Rovang, D C; Ruiz, C L; Savage, M E; Smith, I C; Stygar, W A; Vesey, R A

2014-10-10

177

Understanding Fuel Magnetization and Mix Using Secondary Nuclear Reactions in Magneto-Inertial Fusion  

NASA Astrophysics Data System (ADS)

Magnetizing the fuel in inertial confinement fusion relaxes ignition requirements by reducing thermal conductivity and changing the physics of burn product confinement. Diagnosing the level of fuel magnetization during burn is critical to understanding target performance in magneto-inertial fusion (MIF) implosions. In pure deuterium fusion plasma, 1.01 MeV tritons are emitted during deuterium-deuterium fusion and can undergo secondary deuterium-tritium reactions before exiting the fuel. Increasing the fuel magnetization elongates the path lengths through the fuel of some of the tritons, enhancing their probability of reaction. Based on this feature, a method to diagnose fuel magnetization using the ratio of overall deuterium-tritium to deuterium-deuterium neutron yields is developed. Analysis of anisotropies in the secondary neutron energy spectra further constrain the measurement. Secondary reactions also are shown to provide an upper bound for the volumetric fuel-pusher mix in MIF. The analysis is applied to recent MIF experiments [M. R. Gomez et al., Phys. Rev. Lett. 113, 155003 (2014), 10.1103/PhysRevLett.113.155003] on the Z Pulsed Power Facility, indicating that significant magnetic confinement of charged burn products was achieved and suggesting a relatively low-mix environment. Both of these are essential features of future ignition-scale MIF designs.

Schmit, P. F.; Knapp, P. F.; Hansen, S. B.; Gomez, M. R.; Hahn, K. D.; Sinars, D. B.; Peterson, K. J.; Slutz, S. A.; Sefkow, A. B.; Awe, T. J.; Harding, E.; Jennings, C. A.; Chandler, G. A.; Cooper, G. W.; Cuneo, M. E.; Geissel, M.; Harvey-Thompson, A. J.; Herrmann, M. C.; Hess, M. H.; Johns, O.; Lamppa, D. C.; Martin, M. R.; McBride, R. D.; Porter, J. L.; Robertson, G. K.; Rochau, G. A.; Rovang, D. C.; Ruiz, C. L.; Savage, M. E.; Smith, I. C.; Stygar, W. A.; Vesey, R. A.

2014-10-01

178

Motional averaging of quadrupole interactions in Al4Sr and Ga4Sr studied using PAC  

NASA Astrophysics Data System (ADS)

Perturbed angular correlation of gamma rays (PAC) was used to study diffusion of ^111In/Cd probe atoms in Al4Sr and Ga4Sr phases. These phases have the tetragonal Al4Ba structure, with two inequivalent Al sublattices that have axially symmetric and collinear electric field gradients. Measurements of nuclear quadrupole interactions in each phase revealed three dynamical regimes. Static quadrupole interactions were observed below 500^oC. Between 500 and 700^oC, the two quadrupole interaction signals were observed to approach each other and merge at 700^oC (slow fluctuation regime). Only a single quadrupole interaction signal was observed above 700^oC (fast fluctuation regime). These changes are attributed to jumping of probe atoms between the two sublattices, leading to motional averaging of the two electric field gradients as temperature and jump frequency increase. The two signals merge at a temperature at which the jump frequency between the sublattices is equal to the difference in the static quadrupole interaction frequencies. Temperature dependences of the quadrupole interaction frequencies will be contrasted with those measured earlier on phases including Al4Ba and In4Ba.

Cawthorne, Samantha; Collins, Gary S.

2009-11-01

179

Toward Understanding the Effect of Nuclear Waste Glass Composition on Sulfur Solubility  

SciTech Connect

The concentration of sulfur in nuclear waste glass melter feed must be maintained below the point where salt accumulates on the melt surface. The allowable concentrations may range from 0.37 to over 2.05 weight percent (of SO3 on a calcined oxide basis) depending on the composition of the melter feed and processing conditions. If the amount of sulfur exceeds the melt tolerance level, a molten salt will accumulate, which may upset melter operations and potentially shorten the useful life of the melter. At the Hanford site, relatively conservative limits have been placed on sulfur loading in melter feed, which in turn significantly increases the amount of glass that will be produced. Crucible-scale sulfur solubility data and scaled melter sulfur tolerance data have been collected on simulated Hanford waste glasses over the last 15 years. These data were compiled and analyzed. A model was developed to predict the solubility of SO3 in glass based on 252 simulated Hanford low-activity waste (LAW) glass compositions. This model represents the data well, accounting for over 85% of the variation in data, and was well validated. The model was also found to accurately predict the tolerance for sulfur in melter feed for 13 scaled melter tests of simulated LAW glasses. The model can be used to help estimate glass volumes and make informed decisions on process options. The model also gives quantitative estimates of component concentration effects on sulfur solubility. The components that most increase sulfur solubility are Li2O > V2O5> CaO ? P2O5 > Na2O ? B2O3 > K2O. The components that most decrease sulfur solubility are Cl > Cr2O3 > Al2O3 > ZrO2 ? SnO2 > Others ? SiO2. The order of component effects is similar to previous literature data, in most cases.

Vienna, John D. [Pacific Northwest National Laboratory; Kim, Dong-Sang [Pacific Northwest National Laboratory; Muller, I. S. [The Catholic University National Laboratory; Kruger, Albert A. [Department of Energy -- Ofice of River Protection; Piepel, Gregory F. [Pacific Northwest National Laboratory

2014-10-01

180

Ground-state electric quadrupole moment of Al31  

NASA Astrophysics Data System (ADS)

The ground-state electric quadrupole moment of Al31(I?=5/2+,T1/2=644(25)ms) has been measured by means of ?-ray-detected nuclear magnetic resonance spectroscopy using a spin-polarized Al31 beam produced in the projectile fragmentation reaction. The obtained Q moment, |Qexp(Al31)|=112(32)emb, is in agreement with conventional shell model calculations within the sd valence space. Previous results on the magnetic moment also support the validity of the sd model in this isotope, and thus it is concluded that Al31 is located outside of the island of inversion.

Nagae, D.; Ueno, H.; Kameda, D.; Takemura, M.; Asahi, K.; Takase, K.; Yoshimi, A.; Sugimoto, T.; Shimada, K.; Nagatomo, T.; Uchida, M.; Arai, T.; Inoue, T.; Kagami, S.; Hatakeyama, N.; Kawamura, H.; Narita, K.; Murata, J.

2009-02-01

181

Quadrupole effects in 63 Cu NMR spectroscopy of copper nanocrystals  

Microsoft Academic Search

Quadrupole effects in room-temperature continuous-wave (CW)63Cu nuclear magnetic resonance (NMR) spectra, “?\\/2” pulse length shortening and amplitudes of two-pulse generated echoes were\\u000a investigated on nanocrystalline copper powders produced by cryogenic melting and by ball milling techniques. Systematic measurements\\u000a on the parent polycrystalline copper and on copper-based copper-palladium dilute alloys on the basis of the same experimental\\u000a techniques were also made

K. Tompa; P. Bánki; M. Bokor; G. Lasanda; L. K. Varga; Y. Champion; L. Takács

2004-01-01

182

QUADRUPOLE BEAM-BASED ALIGNMENT AT RHIC.  

SciTech Connect

Successful implementation of a beam-based alignment algorithm, tailored to different types of quadrupoles at RHIC, provides significant benefits to machine operations for heavy ions and polarized protons. This algorithm was used to calibrate beam position monitor centers relative to interaction region quadrupoles to maximize aperture. This approach was also used to determine the optimal orbit through transition jump quadrupoles to minimize orbit changes during the transition jump for heavy ion acceleration. This paper provides background discussion and results from first measurements during the RHIC 2005 run.

NIEDZIELA, J.; MONTAG, C.; SATOGATA, T.

2005-05-16

183

Understanding public responses to chemical, biological, radiological and nuclear incidents--driving factors, emerging themes and research gaps.  

PubMed

This paper discusses the management of public responses to incidents involving chemical, biological, radiological and nuclear materials (CBRN). Given the extraordinary technical and operational challenges of a response to a CBRN release including, but not limited to, hazard detection and identification, casualty decontamination and multi-agency co-ordination, it is not surprising that public psychological and behavioural responses to such incidents have received limited attention by scholars and practitioners alike. As a result, a lack of understanding about the role of the public in effective emergency response constitutes a major gap in research and practice. This limitation must be addressed as a CBRN release has the potential to have wide-reaching psychological and behavioural impacts which, in turn, impact upon public morbidity and mortality rates. This paper addresses a number of key issues: why public responses matter; how responses have been conceptualised by practitioners; what factors have been identified as influencing public responses to a CBRN release and similar extreme events, and what further analysis is needed in order to generate a better understanding of public responses to inform the management of public responses to a CBRN release. PMID:24856235

Krieger, Kristian; Amlôt, Richard; Rogers, M Brooke

2014-11-01

184

Nuclear Magnetic Resonance  

NASA Astrophysics Data System (ADS)

Author's preface; 1. Introduction; 2. Basic theory; 3. Experimental methods; 4. Measurement of nuclear properties and general physical applications; 5. Nuclear magnetic resonance in liquids and gases; 6. Nuclear magnetic resonance in non-metallic solids; 7. Nuclear magnetic resonance in metals; 8. Quadrupole effects; Appendices 1-6; Glossary of symbols; Bibliography and author index; Subject index.

Andrew, E. R.

2009-06-01

185

Klystron having electrostatic quadrupole focusing arrangement  

DOEpatents

A klystron includes a source for emitting at least one electron beam, and an accelerator for accelarating the beam in a given direction through a number of drift tube sections successively aligned relative to one another in the direction of the beam. A number of electrostatic quadrupole arrays are successively aligned relative to one another along at least one of the drift tube sections in the beam direction for focusing the electron beam. Each of the electrostatic quadrupole arrays forms a different quadrupole for each electron beam. Two or more electron beams can be maintained in parallel relationship by the quadrupole arrays, thereby enabling space charge limitations encountered with conventional single beam klystrons to be overcome.

Maschke, Alfred W. (East Moriches, NY)

1983-08-30

186

Nonuniform radiation damage in permanent magnet quadrupoles  

SciTech Connect

We present data that indicate nonuniform magnetization loss due to radiation damage in neodymium-iron-boron Halbach-style permanent magnet quadrupoles. The proton radiography (pRad) facility at Los Alamos uses permanent-magnet quadrupoles for magnifying lenses, and a system recently commissioned at GSI-Darmsdadt uses permanent magnets for its primary lenses. Large fluences of spallation neutrons can be produced in close proximity to these magnets when the proton beam is, intentionally or unintentionally, directed into the tungsten beam collimators; imaging experiments at LANL’s pRad have shown image degradation with these magnetic lenses at proton beam doses lower than those expected to cause damage through radiation-induced reduction of the quadrupole strength alone. We have observed preferential degradation in portions of the permanent magnet quadrupole where the field intensity is highest, resulting in increased high-order multipole components.

Danly, C. R.; Merrill, F. E.; Barlow, D.; Mariam, F. G. [Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States)

2014-08-15

187

Klystron having electrostatic quadrupole focusing arrangement  

DOEpatents

A klystron includes a source for emitting at least one electron beam, and an accelerator for accelerating the beam in a given direction through a number of drift tube sections successively aligned relative to one another in the direction of the beam. A number of electrostatic quadrupole arrays are successively aligned relative to one another along at least one of the drift tube sections in the beam direction for focusing the electron beam. Each of the electrostatic quadrupole arrays forms a different quadrupole for each electron beam. Two or more electron beams can be maintained in parallel relationship by the quadrupole arrays, thereby enabling space charge limitations encountered with conventional single beam klystrons to be overcome. 4 figs.

Maschke, A.W.

1983-08-30

188

Coherent manipulation of quadrupole biexcitons in cuprous  

E-print Network

Coherent manipulation of quadrupole biexcitons in cuprous oxide by 2D femtosecond spectroscopy excitons from the ortho­para excitons picture is that the positions of the biexciton resonances are defined

Mukamel, Shaul

189

Nonuniform radiation damage in permanent magnet quadrupoles.  

PubMed

We present data that indicate nonuniform magnetization loss due to radiation damage in neodymium-iron-boron Halbach-style permanent magnet quadrupoles. The proton radiography (pRad) facility at Los Alamos uses permanent-magnet quadrupoles for magnifying lenses, and a system recently commissioned at GSI-Darmsdadt uses permanent magnets for its primary lenses. Large fluences of spallation neutrons can be produced in close proximity to these magnets when the proton beam is, intentionally or unintentionally, directed into the tungsten beam collimators; imaging experiments at LANL's pRad have shown image degradation with these magnetic lenses at proton beam doses lower than those expected to cause damage through radiation-induced reduction of the quadrupole strength alone. We have observed preferential degradation in portions of the permanent magnet quadrupole where the field intensity is highest, resulting in increased high-order multipole components. PMID:25173260

Danly, C R; Merrill, F E; Barlow, D; Mariam, F G

2014-08-01

190

Nonuniform radiation damage in permanent magnet quadrupoles  

NASA Astrophysics Data System (ADS)

We present data that indicate nonuniform magnetization loss due to radiation damage in neodymium-iron-boron Halbach-style permanent magnet quadrupoles. The proton radiography (pRad) facility at Los Alamos uses permanent-magnet quadrupoles for magnifying lenses, and a system recently commissioned at GSI-Darmsdadt uses permanent magnets for its primary lenses. Large fluences of spallation neutrons can be produced in close proximity to these magnets when the proton beam is, intentionally or unintentionally, directed into the tungsten beam collimators; imaging experiments at LANL's pRad have shown image degradation with these magnetic lenses at proton beam doses lower than those expected to cause damage through radiation-induced reduction of the quadrupole strength alone. We have observed preferential degradation in portions of the permanent magnet quadrupole where the field intensity is highest, resulting in increased high-order multipole components.

Danly, C. R.; Merrill, F. E.; Barlow, D.; Mariam, F. G.

2014-08-01

191

Permanent magnet edge-field quadrupole  

DOEpatents

Planar permanent magnet edge-field quadrupoles for use in particle accelerating machines and in insertion devices designed to generate spontaneous or coherent radiation from moving charged particles are disclosed. The invention comprises four magnetized rectangular pieces of permanent magnet material with substantially similar dimensions arranged into two planar arrays situated to generate a field with a substantially dominant quadrupole component in regions close to the device axis.

Tatchyn, Roman O. (Mountain View, CA)

1997-01-01

192

Laced permanent magnet quadrupole drift tube magnets  

Microsoft Academic Search

A laced permanent magnet quadrupole drift tube magnet has been constructed for a proof-of-principle test. The magnet is a conventional tape-wound quadrupole electromagnet, using iron pole- pieces, with the addition of permanent magnet material (neodymium iron) between the poles to reduce the effects of saturation. The iron is preloaded with magnetic flux generated by the permanent magnet material, resulting in

B. Feinberg; G. U. Behrsing; K. Halbach; J. S. Marks; M. E. Morrison; D. H. Nelson

1988-01-01

193

Miniature quadrupole mass spectrometer array  

NASA Technical Reports Server (NTRS)

The present invention provides a minature quadrupole mass spectrometer array for the separation of ions, comprising a first pair of parallel, planar, nonmagnetic conducting rods each having an axis of symmetry, a second pair of planar, nonmagnetic conducting rods each having an axis of symmetry parallel to said first pair of rods and disposed such that a line perpendicular to each of said first axes of symmetry and a line perpendicular to each of said second axes of symmetry bisect each other and form a generally 90 degree angle. A nonconductive top positioning plate is positioned generally perpendicular to the first and second pairs of rods and has an aperture for ion entrance along an axis equidistant from each axis of symmetry of each of the parallel rods, a nonconductive bottom positioning plate is generally parallel to the top positioning plate and has an aperture for ion exit centered on an axis equidistant from each axis of symmetry of each of the parallel rods, means for maintaining a direct current voltage between the first and second pairs of rods, and means for applying a radio frequency voltage to the first and second pairs of rods.

Chutjian, Ara (Inventor); Hecht, Michael H. (Inventor); Orient, Otto J. (Inventor)

1998-01-01

194

Miniature quadrupole mass spectrometer array  

NASA Technical Reports Server (NTRS)

The present invention provides a minature quadrupole mass spectrometer array for the separation of ions, comprising a first pair of parallel, planar, nonmagnetic conducting rods each having an axis of symmetry, a second pair of planar, nonmagnetic conducting rods each having an axis of symmetry parallel to said first pair of rods and disposed such that a line perpendicular to each of said first axes of symmetry and a line perpendicular to each of said second axes of symmetry bisect each other and form a generally 90 degree angle. A nonconductive top positioning plate is positioned generally perpendicular to the first and second pairs of rods and has an aperture for ion entrance along an axis equidistant from each axis of symmetry of each of the parallel rods, a nonconductive bottom positioning plate is generally parallel to the top positioning plate and has an aperture for ion exit centered on an axis equidistant from each axis of symmetry of each of the parallel rods, means for maintaining a direct current voltage between the first and second pairs of rods, and means for applying a radio frequency voltage to the first and second pairs of rods.

Chutjian, Ara (Inventor); Hecht, Michael H. (Inventor); Orient, Otto J. (Inventor)

1997-01-01

195

Integrally formed radio frequency quadrupole  

DOEpatents

An improved radio frequency quadrupole (10) is provided having an elongate housing (11) with an elongate central axis (12) and top, bottom and two side walls (13a-d) symmetrically disposed about the axis, and vanes (14a-d) formed integrally with the walls (13a-d), the vanes (14a-d) each having a cross-section at right angles to the central axis (12) which tapers inwardly toward the axis to form electrode tips (15a-d) spaced from each other by predetermined distances. Each of the four walls (13a-d), and the vanes (14a-d) integral therewith, is a separate structural element having a central lengthwise plane (16) passing through the tip of the vane, the walls (13a-d) having flat mounting surfaces (17, 18) at right angles to and parallel to the control plane (16), respectively, which are butted together to position the walls and vane tips relative to each other.

Abbott, Steven R. (Concord, CA)

1989-01-01

196

Production of 62Zn radioactive nuclear beam and on-line PAC investigation of quadrupole interaction in nano-magnetic material Fe73.5Cu1Nb3Si13.5B9  

NASA Astrophysics Data System (ADS)

An Isotope Separator On-Line (ISOL), dedicated to on-line perturbed angular correlation (PAC) and positron annihilation spectroscopy (PAS), has been constructed at CIAE based on the HI-13 tandem accelerator, and a 30 keV radioactive beam of 62Zn with intensity of 2 ×107/s produced by it. Using the 62Zn radioactive beam the investigation of the nano-crystalline soft magnetic Fe73.5Cu1Nb3Si13.5B9 materials has been fulfiled for the first time by the on-line time differential PAC technique. Two quadrupole interaction frequencies ? 01 ( = 440 Mrad/s) and ? 02 ( = 90 Mrad/s) were gained, indicating there are two implantation sites of 62Zn. The frequency ? 02 shows a fluctuation of the crystal lattice constants and proves the characteristic distribution model of nano-crystalline grain boundary. The frequency ? 01 demonstrates that the implanted 62Zn occupies the site of the ordered grain core. The fractions of ? 01 and ? 02 are f01 = 38 % and f02 = 62 %, respectively.

Zuo, Yi; Zheng, Yongnan; Xu, Yongjun; Cui, Baoqun; Li, Liqiang; Ma, Yingjun; Ping, Fan; Yuan, Daqing; Gao, Shuang; Zhu, Shengyun

2013-05-01

197

75 FR 1416 - Final Memorandum of Understanding Between the U.S. Nuclear Regulatory Commission and the North...  

Federal Register 2010, 2011, 2012, 2013, 2014

...assets, including digital control and data acquisition...preparedness functions of a nuclear power plant. The NRC will inspect...preparedness functions of a nuclear power plant, such as those digital control and data...

2010-01-11

198

Systematics of quadrupole moments and energies  

E-print Network

We define the "quadrupole ratio" r_{Q}=\\dfrac{Q_{0}(S)}{Q_{0}(B)} where Q_{0}(S) is the intrinsic quadrupole moment obtained from the static quadrupole moment of the 2_{1}^{+} state of an even-even nucleus and Q_{0}(B) the intrinsic quadrupole moment obtained from B(E2)_{0\\rightarrow2} . In both cases we assume a simple rotational formula connecting the rotating frame to the laboratory frame. The quantity r_{Q} would be one if the rotational model were perfect and the energy ratio E(4)/E(2) would be 10/3. In the simple vibrational model, r_{Q} would be zero and E(4)/E(2) would be two. There are some regions where the rotational limit is almost met and fewer where the vibrational limit is also almost met. For most cases, however, it is between these two limits, i.e. 0light nuclei. In most cases the quadrupole ratio is positive but there are two regions with negative ratios. The first case is that of light nuclei and the second has certain nuclei close to ^{208} Pb.

S. Yeager; L. Zamick; Y. Y. Sharon; S. J. Q. Robinson

2012-08-13

199

Microfluidic quadrupole and floating concentration gradient  

PubMed Central

The concept of fluidic multipoles, in analogy to electrostatics, has long been known as a particular class of solutions of the Navier-Stokes equation in potential flows, however, experimental observations of fluidic multipoles and of their characteristics have not been reported yet. Here we present a two-dimensional microfluidic quadrupole and a theoretical analysis consistent with the experimental observations. The microfluidic quadrupole was formed by simultaneously injecting and aspirating fluids from two pairs of opposing apertures in a narrow gap formed between a microfluidic probe and a substrate. A stagnation point was formed at the center of the microfluidic quadrupole, and its position could be rapidly adjusted hydrodynamically. Following the injection of a solute through one of the poles, a stationary, tunable, and movable – i.e. “floating” – concentration gradient was formed at the stagnation point. Our results lay the foundation for future combined experimental and theoretical exploration of microfluidic planar multipoles including convective-diffusive phenomena. PMID:21897375

Qasaimeh, Mohammad A.; Gervais, Thomas; Juncker, David

2014-01-01

200

Variable gradient permanent-magnet quadrupole lenses  

SciTech Connect

Rare earth (RE) permanent-magnet quadrupoles (PMQs) have been used for many applications in particle accelerators. They have the advantage over electromagnets of being lightweight and reliable. One difficulty associated with PMQs is that the quadrupole gradient is not easily adjusted. Over a certain range, the magnetization of RE magnets is a reversible function of temperature. We have developed a scheme to use this property to make variable gradient PMQs. The field gradient changes required for tuning are typically on the order of a few percent. For many RE magnets, this requires temperature changes of a few tens of degrees centigrade and is accomplished by actively heating or cooling the quadrupoles. 8 refs., 7 figs.

O'Shea, P.G.; Zaugg, T.J.; Maggs, R.G.; Schafstall, P.; Dyson, J.E.

1989-01-01

201

Quadrupole mass filters with added hexapole fields.  

PubMed

Conventional mass analysis has been investigated experimentally with six quadrupole mass filters with added hexapole fields; three with added hexapole fields of 4%, 8% and 12% with equal diameter rods, and three with added hexapole fields of 4%, 8% and 12% with unequal diameter rods to remove an added octopole field. Compared with conventional quadrupoles, these rod sets have very large field distortions. With the positive resolving dc applied to the y rods (Mathieu parameter a(x) < 0) only low resolution (10-100) and low transmission are seen. With the polarity reversed (a(x) > 0) much higher resolution (> or = 1000) and transmission are possible. Increasing the magnitude of the added hexapole field decreases the limiting resolution at m/z 609. Removing the added octopole field increases the limiting resolution. In some cases structure is formed on the peaks. For a given scan line slope, U/V(rf), the resolution decreases as the amplitude of the added hexapole field increases. These results are consistent with changes to the stability diagrams, calculated here. With a(x) > 0, adding a hexapole field causes the x stability boundary to move outward with all rod sets. With a(x) < 0, the boundaries become diffuse and the tip of the stability diagram becomes rounded, limiting the resolution to ca. 10-100. Where comparisons are possible, experiments show the rod sets with added hexapole fields have transmission 10-300 times less than a conventional quadrupole. Thus these quadrupoles are less useful for mass analysis than conventional quadrupoles. However, it is surprising, given the highly distorted fields, that some of the quadrupoles give resolution of 1000 or more. PMID:20552578

Xiao, Zilan; Zhao, XianZhen; Douglas, D J

2010-07-30

202

Magnetic Measurement Results of the LCLS Undulator Quadrupoles  

SciTech Connect

This note details the magnetic measurements and the magnetic center fiducializations that were performed on all of the thirty-six LCLS undulator quadrupoles. Temperature rise, standardization reproducibility, vacuum chamber effects and magnetic center reproducibility measurements are also presented. The Linac Coherent Light Source (LCLS) undulator beam line has 33 girders, each with a LCLS undulator quadrupole which focuses and steers the beam through the beam line. Each quadrupole has main quadrupole coils, as well as separate horizontal and vertical trim coils. Thirty-six quadrupoles, thirty-three installed and three spares were, manufactured for the LCLS undulator system and all were measured to confirm that they met requirement specifications for integrated gradient, harmonics and for magnetic center shifts after current changes. The horizontal and vertical dipole trims of each quadrupole were similarly characterized. Each quadrupole was also fiducialized to its magnetic center. All characterizing measurements on the undulator quads were performed with their mirror plates on and after a standardization of three cycles from -6 to +6 to -6 amps. Since the undulator quadrupoles could be used as a focusing or defocusing magnet depending on their location, all quadrupoles were characterized as focusing and as defocusing quadrupoles. A subset of the undulator quadrupoles were used to verify that the undulator quadrupole design met specifications for temperature rise, standardization reproducibility and magnetic center reproducibility after splitting. The effects of the mirror plates on the undulator quadrupoles were also measured.

Anderson, Scott; Caban, Keith; Nuhn, Heinz-Dieter; Reese, Ed; Wolf, Zachary; /SLAC; ,

2011-08-18

203

Electric quadrupole transition probabilities for atomic lithium  

SciTech Connect

Electric quadrupole transition probabilities for atomic lithium have been calculated using the weakest bound electron potential model theory (WBEPMT). We have employed numerical non-relativistic Hartree–Fock wavefunctions for expectation values of radii and the necessary energy values have been taken from the compilation at NIST. The results obtained with the present method agree very well with the Coulomb approximation results given by Caves (1975). Moreover, electric quadrupole transition probability values not existing in the literature for some highly excited levels have been obtained using the WBEPMT.

Çelik, Gültekin, E-mail: gultekin@selcuk.edu.tr [Department of Physics, Faculty of Science, Selçuk University, Campus 42049 Konya (Turkey); Gökçe, Yasin; Y?ld?z, Murat [Department of Physics, Faculty of Science, Karamanoglu Mehmetbey University, Karaman (Turkey)

2014-05-15

204

Chip-Scale Quadrupole Mass Filters for Portable Mass Spectrometry  

E-print Network

We report the design, fabrication, and characterization of a new class of chip-scale quadrupole mass filter (QMF). The devices are completely batch fabricated using a wafer-scale process that integrates the quadrupole ...

Cheung, Kerry

205

Quadrupole anisotropy from photon quantum effects  

E-print Network

We consider quantum effects of an electromagnetic field in a radiation-dominated almost FRW spacetime. The dominant non-local quantum correction to the photon distribution is a quadrupole moment, corresponding to an effective anisotropic pressure in the energy-momentum tensor.

Alexei V Nesteruk; Roy Maartens

1995-11-15

206

Giant Quadrupole-Resonance in Ni Isotopes  

E-print Network

Inelastic scattering of 129 MeV alpha particles has been used to excite the giant quadrupole resonance in Ni-58, Ni-60, Ni-62, Ni-64. The resonance was found to exhaust 58 +/- 12%, 76 +/- 14%, 78 +/- 14%, and 90 +/-16% of the E2 energy-weighted sum...

Youngblood, David H.; Lui, YW; Garg, U.; Peterson, R. J.

1992-01-01

207

Hydrogen isotope analysis by quadrupole mass spectrometry  

Microsoft Academic Search

The analysis of isotopes of hydrogen (H, D, T) and helium (³He, He) and selected impurities using a quadrupole mass spectrometer (QMS) has been investigated as a method of measuring the purity of tritium gas for injection into the Tokamak Fusion Test Reactor (TFTR). A QMS was used at low resolution, m\\/..delta..m < 150, for quantifying impurities from m\\/q =

R. E. Ellefson; W. E. Moddeman; H. F. Dylla

1981-01-01

208

Super Strong Permanent Magnet Quadrupole for  

Microsoft Academic Search

The field strength generated by permanent magnets has been further extended by introduction of saturated iron. A permanent magnet quadrupole (PMQ) lens with such saturated iron is one of the candidates for the final focus lens for an e+e- Linear Collider accelerator, because of its compactness and low power consumption. The first prototype of the PMQ has been fabricated and

Takanori Mihara; Yoshihisa Iwashita; Masayuki Kumada; Antokhin Evgeny; Cherrill M. Spencer

209

Tevatron low-beta quadrupole triplet interconnects  

SciTech Connect

Installation of cold iron quadrupole magnets in the Low Beta (Superconducting High-Luminosity) upgrade at Fermilab required a newly designed magnet interconnect. The interconnect design and construction experience is presented. Considered are the connections carrying cryogenic fluids, beam vacuum, insulating vacuum, superconducting bus leads, their insulation and mechanical support. Details of the assembly and assembly experience are presented. 2 refs.

Oleck, A.R.; Carson, J.A.; Koepke, K.; Sorenson, D.

1992-04-01

210

LARP Long $Nb_{3}Sn$ Quadrupole  

E-print Network

A major milestone for the LHC Accelerator Research Program (LARP) is the test, by the end of 2009, of two 4m-long quadrupole magnets (LQ) wound with Nb3Sn conductor. The goal of these magnets is to be a proof of principle that Nb3Sn is a viable technology for a possible LHC luminosity upgrade.

Ambrosio, G

2008-01-01

211

Nuclear Deformation at Finite Temperature  

NASA Astrophysics Data System (ADS)

Deformation, a key concept in our understanding of heavy nuclei, is based on a mean-field description that breaks the rotational invariance of the nuclear many-body Hamiltonian. We present a method to analyze nuclear deformations at finite temperature in a framework that preserves rotational invariance. The auxiliary-field Monte Carlo method is used to generate a statistical ensemble and calculate the probability distribution associated with the quadrupole operator. Applying the technique to nuclei in the rare-earth region, we identify model-independent signatures of deformation and find that deformation effects persist to temperatures higher than the spherical-to-deformed shape phase-transition temperature of mean-field theory.

Alhassid, Y.; Gilbreth, C. N.; Bertsch, G. F.

2014-12-01

212

Nuclear deformation at finite temperature.  

PubMed

Deformation, a key concept in our understanding of heavy nuclei, is based on a mean-field description that breaks the rotational invariance of the nuclear many-body Hamiltonian. We present a method to analyze nuclear deformations at finite temperature in a framework that preserves rotational invariance. The auxiliary-field Monte Carlo method is used to generate a statistical ensemble and calculate the probability distribution associated with the quadrupole operator. Applying the technique to nuclei in the rare-earth region, we identify model-independent signatures of deformation and find that deformation effects persist to temperatures higher than the spherical-to-deformed shape phase-transition temperature of mean-field theory. PMID:25615315

Alhassid, Y; Gilbreth, C N; Bertsch, G F

2014-12-31

213

Covariant Spectator Theory of np scattering: Deuteron Quadrupole Moment  

DOE PAGESBeta

The deuteron quadrupole moment is calculated using two CST model wave functions obtained from the 2007 high precision fits to $np$ scattering data. Included in the calculation are a new class of isoscalar $np$ interaction currents automatically generated by the nuclear force model used in these fits. The prediction for model WJC-1, with larger relativistic P-state components, is $2.5\\%$ smaller that the experiential result, in common with the inability of models prior to 2014 to predict this important quantity. However, model WJC-2, with very small P-state components, gives agreement to better than 1\\%, similar to the results obtained recently from $\\chi$EFT predictions to order N$^3$LO.

Gross, Franz

2015-01-01

214

Measurement of the spectroscopic quadrupole moment of 186Au: Experimental verification of the large prolate deformation of the186Au ground state  

NASA Astrophysics Data System (ADS)

We report the first on-line measurements of quadrupole-interaction-resolved nuclear magnetic resonance on oriented nuclei. The 10-min 186Au activity was obtained as daughter after cold implantation of mass-separated 186Hg into a hcp Co single crystal at the NICOLE facility at ISOLDE-3 (CERN). The quadrupole interaction of 186Co(hcp) was fully resolved, and the spectroscopic quadrupole moment of 186Au was determined to be Q=+3.12(20) b. This implies ?2=+0.246(16), proving the large prolate deformation of the 186Au ground state.

Hinfurtner, B.; Hagn, E.; Zech, E.; Eder, R.

1991-08-01

215

Microwave spectrum of GeF2: quadrupole coupling and centrifugal distortion  

Microsoft Academic Search

The nuclear quadrupole coupling constants of 73GeF2 have been determined and are chiaa = 17.2 +\\/- 1., chibb 121.7 +\\/- 1., chicc = -138.9 +\\/- 1 MHz. These constants are interpreted in terms of the bonding. The effects of centrifugal distortion on the microwave spectrum of GeF2 have been investigated. It is found that for J < 10 the rotational

H. Takeo; R. F. Curl

1972-01-01

216

A preliminary quadrupole asymmetry study of a ?=0.12 superconducting single spoke cavity  

NASA Astrophysics Data System (ADS)

An Accelerator Driven System (ADS) has been launched in China for nuclear waste transmutation. For the application of high intensity proton beam acceleration, the quadrupole asymmetry effect needs to be carefully evaluated for cavities. Single spoke cavities are the main accelerating structures in the low energy front-end. The single spoke cavity has small transverse electromagnetic field asymmetry, which may lead to transverse RF defocusing asymmetry and beam envelope asymmetry. A superconducting single spoke resonator (PKU-2 Spoke) of ?=0.12 and f=325 MHz with a racetrack-shaped inner conductor has been designed at Peking university. The study of its RF field quadrupole asymmetry and its effect on transverse momentum change has been performed. The quadrupole asymmetry study has also been performed on a ?=0.12 and f=325 MHz ring-shaped single spoke cavity. Our results show that the quadrupole asymmetry is very small for both the racetrack-shaped and the ring-shaped single spoke cavity.

Yang, Zi-Qin; Lu, Xiang-Yang; Yang, Liu; Luo, Xing; Zhou, Kui; Quan, Sheng-Wen

2014-10-01

217

LARP Long Nb3Sn Quadrupole Design.  

SciTech Connect

A major milestone for the LHC Accelerator Research Program (LARP) is the test, by the end of 2009, of two 4m-long quadrupole magnets (LQ) wound with Nb{sub 3}Sn conductor. The goal of these magnets is to be a proof of principle that Nb{sub 3}Sn is a viable technology for a possible LHC luminosity upgrade. The design of the LQ is based on the design of the LARP Technological Quadrupoles, presently under development at FNAL and LBNL, with 90-mm aperture and gradient higher than 200 T/m. The design of the first LQ model will be completed by the end of 2007 with the selection of a mechanical design. In this paper we present the coil design addressing some fabrication technology issues, the quench protection study, and three designs of the support structure.

Ambrosio,G.; Andreev, N.; Anerella, M.; Barzi, E.; Bossert, R.; Caspi, S.; Chlachidize, G.; Dietderich, D.; Feher, S.; Felice, H.; Ferracin, P.; Ghosh, A.; Hafalia, A.R.; Hannaford, C.R.; Kashikhin, V.V.; Kerby, J.; Lamm, M.; Lietzke, A.; McInturff, A.; Muratore, J.; Nobrega, F.; Novitsky, I.; Sabbi, G.L.; Schmalzle, J.; Tartaglia, M.; Turrioni, D.; Wanderer, P.; Whitson, G.; Zlobin, A.V.

2007-08-27

218

LARP Long Nb3Sn Quadrupole Design  

SciTech Connect

A major milestone for the LHC Accelerator Research Program (LARP) is the test, by the end of 2009, of two 4m-long quadrupole magnets (LQ) wound with Nb{sub 3}Sn conductor. The goal of these magnets is to be a proof of principle that Nb{sub 3}Sn is a viable technology for a possible LHC luminosity upgrade. The design of the LQ is based on the design of the LARP Technological Quadrupoles, presently under development at FNAL and LBNL, with 90-mm aperture and gradient higher than 200 T/m. The design of the first LQ model will be completed by the end of 2007 with the selection of a mechanical design. In this paper we present the coil design addressing some fabrication technology issues, the quench protection study, and three designs of the support structure.

Ambrosio, G.; Andreev, N.; Anerella, M.; Barzi, E.; Bossert, R.; Caspi, S.; Chlachidize, G.; Dietderich, D.; Feher, S.; Ferracin, P.; Ghosh, A.; Hafalia, R.; Hannaford, R.; Kashikhin, V.V.; Kerby, J.; Lamm, M.; Lietzke, A.; McInturff, A.; Muratore, J.; Nobrega, F.; Novitsky, I.; Sabbi, G.L.; Schmalzle, J.; Tartaglia, M.; Turrioni, D.; Wanderer, P.; Whitson, G.; Zlobin, A.V.

2008-06-01

219

LARP Long Nb3Sn Quadrupole Design  

SciTech Connect

A major milestone for the LHC Accelerator Research Program (LARP) is the test, by the end of 2009, of two 4m-long quadrupole magnets (LQ) wound with Nb3Sn conductor. The goal of these magnets is to be a proof of principle that Nb3Sn is a viable technology for a possible LHC luminosity upgrade. The design of the LQ is based on the design of the LARP Technological Quadrupoles, presently under development at FNAL and LBNL, with 90-mm aperture and gradient higher than 200 T/m. The design of the first LQ model will be completed by the end of 2007 with the selection of a mechanical design. In this paper we present the coil design addressing some fabrication technology issues, the quench protection study, and three designs of the support structure.

Ambrosio, G.; Andreev, N.; Anerella, M.; Barzi, E.; Bossert, R.; Caspi, S.; Chlachidze, G.; Dietderich, D.; Feher, S.; Felice, H.; Ferracin, P.; /Fermilab /Brookhaven /LBL, Berkeley /Texas A-M

2007-08-01

220

Quadrupole transitions revealed by Borrmann spectroscopy.  

PubMed

The Borrmann effect-a dramatic increase in transparency to X-ray beams-is observed when X-rays satisfying Bragg's law diffract through a perfect crystal. The minimization of absorption seen in the Borrmann effect has been explained by noting that the electric field of the X-ray beam approaches zero amplitude at the crystal planes, thus avoiding the atoms. Here we show experimentally that under conditions of absorption suppression, the weaker electric quadrupole absorption transitions are effectively enhanced to such a degree that they can dominate the absorption spectrum. This effect can be exploited as an atomic spectroscopy technique; we show that quadrupole transitions give rise to additional structure at the L(1), L(2) and L(3) absorption edges of gadolinium in gadolinium gallium garnet, which mark the onset of excitations from 2s, 2p(1/2) and 2p(3/2) atomic core levels, respectively. Although the Borrmann effect served to underpin the development of the theory of X-ray diffraction, this is potentially the most important experimental application of the phenomenon since its first observation seven decades ago. Identifying quadrupole features in X-ray absorption spectroscopy is central to the interpretation of 'pre-edge' spectra, which are often taken to be indicators of local symmetry, valence and atomic environment. Quadrupolar absorption isolates states of different symmetries to that of the dominant dipole spectrum, and typically reveals orbitals that dominate the electronic ground-state properties of lanthanides and 3d transition metals, including magnetism. Results from our Borrmann spectroscopy technique feed into contemporary discussions regarding resonant X-ray diffraction and the nature of pre-edge lines identified by inelastic X-ray scattering. Furthermore, because the Borrmann effect has been observed in photonic materials, it seems likely that the quadrupole enhancement reported here will play an important role in modern optics. PMID:18615080

Pettifer, Robert F; Collins, Stephen P; Laundy, David

2008-07-10

221

Hydrogen isotope analysis by quadrupole mass spectrometry  

Microsoft Academic Search

The analysis of isotopes of hydrogen (H,D,T) and helium (³He,⁴He) and selected impurities using a quadrupole mass spectrometer (QMS) has been investigated as a method of measuring the purity of tritium gas for injection into the Tokamak Fusion Test Reactor (TFTR). A QMS was used at low resolution, m\\/Dm<150, for quantifying impurities from m\\/q = 2 to 44, and at

R. E. Ellefson; W. E. Moddeman; H. F. Dylla

1981-01-01

222

Radio frequency quadrupole resonator for linear accelerator  

DOEpatents

An RFQ resonator for a linear accelerator having a reduced level of interfering modes and producing a quadrupole mode for focusing, bunching and accelerating beams of heavy charged particles, with the construction being characterized by four elongated resonating rods within a cylinder with the rods being alternately shorted and open electrically to the shell at common ends of the rods to provide an LC parallel resonant circuit when activated by a magnetic field transverse to the longitudinal axis.

Moretti, Alfred (Downers Grove, IL)

1985-01-01

223

Muon cooling in a quadrupole magnet channel  

SciTech Connect

As discussed before,[1] a cooling channel using quadrupole magnets in a FODO transport channel can be used for initial cooling of muons. In the present note we discuss this possibility of a FODO focusing channel for cooling, and we present ICOOL simulations of muon cooling within a FODO channel. We explore a 1.5m cell-length cooling channel that could be used for the initial transverse cooling stage of a muon collider or neutrino factory.

Neuffer, David; /Fermilab; Poklonskiy, A.; /Michigan State U.

2007-10-01

224

LARP Long Nb3Sn Quadrupole Design  

Microsoft Academic Search

A major milestone for the LHC Accelerator Research Program (LARP) is the test, by the end of 2009, of two 4m-long quadrupole magnets (LQ) wound with NbSn conductor. The goal of these magnets is to be a proof of principle that NbSn is a viable technology for a possible LHC luminosity upgrade. The design of the LQ is based on

G. Ambrosio; N. Andreev; M. Anerella; E. Barzi; R. Bossert; S. Caspi; G. Chlachidize; D. Dietderich; S. Feher; H. Felice; P. Ferracin; A. Ghosh; A. R. Hafalia; C. R. Hannaford; V. V. Kashikhin; J. Kerby; M. Lamm; A. Lietzke; A. McInturff; J. Muratore; F. Nobrega; I. Novitsky; G. L. Sabbi; J. Schmalzle; M. Tartaglia; D. Turrioni; P. Wanderer; G. Whitson; A. V. Zlobin

2007-01-01

225

LARP Long Nb_{3}Sn Quadrupole Design  

Microsoft Academic Search

A major milestone for the LHC Accelerator Research Program (LARP) is the test, by the end of 2009, of two 4m-long quadrupole magnets (LQ) wound with NbSn conductor. The goal of these magnets is to be a proof of principle that NbSn is a viable technology for a possible LHC luminosity upgrade. The design of the LQ is based on

G. Ambrosio; N. Andreev; M. Anerella; E. Barzi; R. Bossert; S. Caspi; G. Chlachidize; D. Dietderich; S. Feher; H. Felice; P. Ferracin; A. Ghosh; R. Hannaford; V. V. Kashikhin; J. Kerby; M. Lamm; A. Lietzke; A. McInturff; J. Muratore; F. Nobrega; I. Novitsky; G. L. Sabbi; J. Schmalzle; M. Tartaglia; D. Turrioni; P. Wanderer; G. Whitson; A. V. Zlobin

2008-01-01

226

A Ligand-Based Approach to Understanding Selectivity of Nuclear Hormone Receptors PXR, CAR, FXR, LXR?, and LXR?  

Microsoft Academic Search

In recent years discussion of nuclear hormone receptors, transporters, and drug-metabolizing enzymes has begun to take place as our knowledge of the overlapping ligand specificity of each of these proteins has deepened. This ligand specificity is potentially valuable information for influencing future drug design, as it is important to avoid certain enzymes or transporters in order to circumvent potential drug–drug

Sean Ekins; Leonid Mirny; Erin G. Schuetz

2002-01-01

227

Photoassociation of a cold-atom-molecule pair: Long-range quadrupole-quadrupole interactions  

SciTech Connect

The general formalism of the multipolar expansion of electrostatic interactions is applied to the calculation of the potential energy between an excited atom (without fine structure) and a ground-state diatomic molecule at large mutual separations. Both partners exhibit a permanent quadrupole moment so that their mutual long-range interaction is dominated by a quadrupole-quadrupole term, which is attractive enough to bind trimers. Numerical results are given for an excited Cs(6{sup 2}P) atom and a ground-state Cs{sub 2} molecule. The prospects for achieving photoassociation of a cold-atom-dimer pair are thus discussed and found promising. The formalism can be generalized to the long-range interaction between molecules to investigate the formation of cold tetramers.

Lepers, M.; Dulieu, O. [Laboratoire Aime Cotton, CNRS, UPR3321, Batiment 505, Universite Paris-Sud, F-91405 Orsay Cedex (France); Kokoouline, V. [Laboratoire Aime Cotton, CNRS, UPR3321, Batiment 505, Universite Paris-Sud, F-91405 Orsay Cedex (France); Department of Physics, University of Central Florida, Orlando, Florida 32816 (United States)

2010-10-15

228

Toward mechanistic understanding of nuclear reprocessing chemistries by quantifying lanthanide solvent extraction kinetics via microfluidics with constant interfacial area and rapid mixing.  

PubMed

The closing of the nuclear fuel cycle is an unsolved problem of great importance. Separating radionuclides produced in a nuclear reactor is useful both for the storage of nuclear waste and for recycling of nuclear fuel. These separations can be performed by designing appropriate chelation chemistries and liquid-liquid extraction schemes, such as in the TALSPEAK process (Trivalent Actinide-Lanthanide Separation by Phosphorus reagent Extraction from Aqueous Komplexes). However, there are no approved methods for the industrial scale reprocessing of civilian nuclear fuel in the United States. One bottleneck in the design of next-generation solvent extraction-based nuclear fuel reprocessing schemes is a lack of interfacial mass transfer rate constants obtained under well-controlled conditions for lanthanide and actinide ligand complexes; such rate constants are a prerequisite for mechanistic understanding of the extraction chemistries involved and are of great assistance in the design of new chemistries. In addition, rate constants obtained under conditions of known interfacial area have immediate, practical utility in models required for the scaling-up of laboratory-scale demonstrations to industrial-scale solutions. Existing experimental techniques for determining these rate constants suffer from two key drawbacks: either slow mixing or unknown interfacial area. The volume of waste produced by traditional methods is an additional, practical concern in experiments involving radioactive elements, both from disposal cost and experimenter safety standpoints. In this paper, we test a plug-based microfluidic system that uses flowing plugs (droplets) in microfluidic channels to determine absolute interfacial mass transfer rate constants under conditions of both rapid mixing and controlled interfacial area. We utilize this system to determine, for the first time, the rate constants for interfacial transfer of all lanthanides, minus promethium, plus yttrium, under TALSPEAK process conditions, as a first step toward testing the molecular mechanism of this separation process. PMID:21888347

Nichols, Kevin P; Pompano, Rebecca R; Li, Liang; Gelis, Artem V; Ismagilov, Rustem F

2011-10-01

229

Ab initio correlated calculations of rare-gas dimer quadrupoles  

SciTech Connect

This paper reports ab initio calculations of rare gas (RG=Kr, Ar, Ne, and He) dimer quadrupoles at the second order of Moeller-Plesset perturbation theory (MP2). The study reveals the crucial role of the dispersion contribution to the RG{sub 2} quadrupole in the neighborhood of the equilibrium dimer separation. The magnitude of the dispersion quadrupole is found to be much larger than that predicted by the approximate model of Hunt. As a result, the total MP2 quadrupole moment is significantly smaller than was assumed in virtually all previous related studies. An analytical model for the distance dependence of the RG{sub 2} quadrupole is proposed. The model is based on the effective-electron approach of Jansen, but replaces the original Gaussian approximation to the electron density in an RG atom by an exponential one. The role of the nonadditive contribution in RG{sub 3} quadrupoles is discussed.

Donchev, Alexander G. [Algodign, LLC, Bolshaya Sadovaya 8, Moscow 123001 (Russian Federation)

2007-10-15

230

Noise reduction in negative-ion quadrupole mass spectrometry  

DOEpatents

A quadrupole mass spectrometer (QMS) system having an ion source, quadrupole mass filter, and ion collector/recorder system. A weak, transverse magnetic field and an electron collector are disposed between the quadrupole and ion collector. When operated in negative ion mode, the ion source produces a beam of primarily negatively-charged particles from a sample, including electrons as well as ions. The beam passes through the quadrupole and enters the magnetic field, where the electrons are deflected away from the beam path to the electron collector. The negative ions pass undeflected to the ion collector where they are detected and recorded as a mass spectrum.

Chastagner, Philippe (3134 Natalie Cir., Augusta, GA 30909-2748)

1993-01-01

231

Noise reduction in negative-ion quadrupole mass spectrometry  

DOEpatents

A quadrupole mass spectrometer (QMS) system is described having an ion source, quadrupole mass filter, and ion collector/recorder system. A weak, transverse magnetic field and an electron collector are disposed between the quadrupole and ion collector. When operated in negative ion mode, the ion source produces a beam of primarily negatively-charged particles from a sample, including electrons as well as ions. The beam passes through the quadrupole and enters the magnetic field, where the electrons are deflected away from the beam path to the electron collector. The negative ions pass undeflected to the ion collector where they are detected and recorded as a mass spectrum.

Chastagner, P.

1993-04-20

232

Magnetic mirror structure for testing shell-type quadrupole coils  

SciTech Connect

This paper presents magnetic and mechanical designs and analyses of the quadrupole mirror structure to test single shell-type quadrupole coils. Several quadrupole coils made of different Nb{sub 3}Sn strands, cable insulation and pole materials were tested using this structure at 4.5 and 1.9 K. The coils were instrumented with voltage taps, spot heaters, temperature sensors and strain gauges to study their mechanical and thermal properties and quench performance. The results of the quadrupole mirror model assembly and test are reported and discussed.

Andreev, N.; Barzi, E.; Bossert, R.; Chlachidze, G.; Kashikhin, V.S.; Kashikhin, V.V.; Lamm, M.J.; Nobrega, F.; Novitski, I.; Tartaglia, N.; Turrioni, D.; /Fermilab

2009-10-01

233

Understanding Genetic Diversity and Population Structure of a Poa pratensis Worldwide Collection through Morphological, Nuclear and Chloroplast Diversity Analysis.  

PubMed

Poa pratensis L. is a forage and turf grass species well adapted to a wide range of mesic to moist habitats. Due to its genome complexity little is known regarding evolution, genome composition and intraspecific phylogenetic relationships of this species. In the present study we investigated the morphological and genetic diversity of 33 P. pratensis accessions from 23 different countries using both nuclear and chloroplast molecular markers as well as flow cytometry of somatic tissues. This with the aim of shedding light on the genetic diversity and phylogenetic relationships of the collection that includes both cultivated and wild materials. Morphological characterization showed that the most relevant traits able to distinguish cultivated from wild forms were spring growth habit and leaf colour. The genome size analysis revealed high variability both within and between accessions in both wild and cultivated materials. The sequence analysis of the trnL-F chloroplast region revealed a low polymorphism level that could be the result of the complex mode of reproduction of this species. In addition, a strong reduction of chloroplast SSR variability was detected in cultivated materials, where only two alleles were conserved out of the four present in wild accessions. Contrarily, at nuclear level, high variability exist in the collection where the analysis of 11 SSR loci allowed the detection of a total of 91 different alleles. A Bayesian analysis performed on nuclear SSR data revealed that studied materials belong to two main clusters. While wild materials are equally represented in both clusters, the domesticated forms are mostly belonging to cluster P2 which is characterized by lower genetic diversity compared to the cluster P1. In the Neighbour Joining tree no clear distinction was found between accessions with the exception of those from China and Mongolia that were clearly separated from all the others. PMID:25893249

Raggi, Lorenzo; Bitocchi, Elena; Russi, Luigi; Marconi, Gianpiero; Sharbel, Timothy F; Veronesi, Fabio; Albertini, Emidio

2015-01-01

234

ANALYTICAL SOLUTIONS OF SINGULAR ISOTHERMAL QUADRUPOLE LENS  

SciTech Connect

Using an analytical method, we study the singular isothermal quadrupole (SIQ) lens system, which is the simplest lens model that can produce four images. In this case, the radial mass distribution is in accord with the profile of the singular isothermal sphere lens, and the tangential distribution is given by adding a quadrupole on the monopole component. The basic properties of the SIQ lens have been studied in this Letter, including the deflection potential, deflection angle, magnification, critical curve, caustic, pseudo-caustic, and transition locus. Analytical solutions of the image positions and magnifications for the source on axes are derived. We find that naked cusps will appear when the relative intensity k of quadrupole to monopole is larger than 0.6. According to the magnification invariant theory of the SIQ lens, the sum of the signed magnifications of the four images should be equal to unity, as found by Dalal. However, if a source lies in the naked cusp, the summed magnification of the left three images is smaller than the invariant 1. With this simple lens system, we study the situations where a point source infinitely approaches a cusp or a fold. The sum of the magnifications of the cusp image triplet is usually not equal to 0, and it is usually positive for major cusps while negative for minor cusps. Similarly, the sum of magnifications of the fold image pair is usually not equal to 0 either. Nevertheless, the cusp and fold relations are still equal to 0 in that the sum values are divided by infinite absolute magnifications by definition.

Chu Zhe; Lin, W. P. [Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030 (China); Yang Xiaofeng, E-mail: chuzhe@shao.ac.cn, E-mail: linwp@shao.ac.cn [School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China)

2013-06-20

235

Multi-Pass Quadrupole Mass Analyzer  

NASA Technical Reports Server (NTRS)

Analysis of the composition of planetary atmospheres is one of the most important and fundamental measurements in planetary robotic exploration. Quadrupole mass analyzers (QMAs) are the primary tool used to execute these investigations, but reductions in size of these instruments has sacrificed mass resolving power so that the best present-day QMA devices are still large, expensive, and do not deliver performance of laboratory instruments. An ultra-high-resolution QMA was developed to resolve N2 +/CO+ by trapping ions in a linear trap quadrupole filter. Because N2 and CO are resolved, gas chromatography columns used to separate species before analysis are eliminated, greatly simplifying gas analysis instrumentation. For highest performance, the ion trap mode is used. High-resolution (or narrow-band) mass selection is carried out in the central region, but near the DC electrodes at each end, RF/DC field settings are adjusted to allow broadband ion passage. This is to prevent ion loss during ion reflection at each end. Ions are created inside the trap so that low-energy particles are selected by low-voltage settings on the end electrodes. This is beneficial to good mass resolution since low-energy particles traverse many cycles of the RF filtering fields. Through Monte Carlo simulations, it is shown that ions are reflected at each end many tens of times, each time being sent back through the central section of the quadrupole where ultrahigh mass filtering is carried out. An analyzer was produced with electrical length orders of magnitude longer than its physical length. Since the selector fields are sized as in conventional devices, the loss of sensitivity inherent in miniaturizing quadrupole instruments is avoided. The no-loss, multi-pass QMA architecture will improve mass resolution of planetary QMA instruments while reducing demands on the RF electronics for high-voltage/high-frequency production since ion transit time is no longer limited to a single pass. The QMA-based instrument will thus give way to substantial reductions of the mass of flight instruments.

Prestage, John D.

2013-01-01

236

The Pipe-Quadrupole, an Alternative for High Gradient Interaction Region Quadrupole Designs  

SciTech Connect

In the design of interaction region (IR) quadrupoles for high luminosity colliders such as the LHC or a possible upgrade of the Tevatron, the radiation heating of the coil windings is an important issue. Two obvious solutions to this problem can be chosen. The first is to reduce the heat load by added shielding, increased cooling with fins or using Nb{sub 3}Sn to increase the temperature margin. The second solution eliminates the conductor from the areas with the highest radiation intensity, which are located on the symmetry-axes of the midplanes of the coils. A novel quadrupole design is presented, in which the conductor is wound on four half-moon shaped supports, forming elongated toroid sections. The assembly of the four shapes yields a quadrupole field with an active flux return path, and a void in the high radiation area. This void can be occupied by a liquid helium cooling pipe to lower the temperature of the windings from the inside. The coil layout, harmonic optimization and mechanical design are shown, together with the calculated temperature rise for the radiation load of the LHC interaction region quadrupoles.

Oort, J.M. van; Scanlan, R.M.

1996-12-12

237

Low-lying 2+ states generated by p n -quadrupole correlation and N =28 shell quenching  

NASA Astrophysics Data System (ADS)

The quadrupole vibrational modes of neutron-rich N =28 isotones (48Ca, 46Ar, 44S, and 42Si) are investigated by using the canonical-basis time-dependent Hartree-Fock-Bogoliubov theory with several choice of energy density functionals, including nuclear pairing correlation. It is found that the quenching of the N =28 shell gap and the proton holes in the s d shell trigger quadrupole correlation and increase the collectivity of the low-lying 2+ state in 46Ar . It is also found that the pairing correlation plays an important role to increase the collectivity. We also demonstrate that the same mechanism to enhance the low-lying collectivity applies to other N =28 isotones 44S and 42Si, and it generates a couple of low-lying 2+ states which can be associated with the observed 2+ states.

Ebata, Shuichiro; Kimura, Masaaki

2015-01-01

238

Observation of Dipole-Quadrupole Interaction in an Ultracold Gas of Rydberg Atoms  

NASA Astrophysics Data System (ADS)

We observe the direct excitation of pairs of Cs atoms from the ground state to molecular states correlating asymptotically to n s n'f asymptotes. The molecular resonances are interpreted as originating from the dipole-quadrupole interaction between the n s n'f pair states and close-by n p n p asymptotes (22 ?n ?32 ). This interpretation is supported by Stark spectroscopy of the pair states and a detailed modeling of the interaction potentials. The dipole-quadrupole interaction mixes electronic states of opposite parity and, thus, requires a coupling between electronic and nuclear motion to conserve the total parity of the system. This non-Born-Oppenheimer coupling is facilitated by the near-degeneracy of even- and odd-L partial waves in the atom-atom scattering which have opposite parity.

Deiglmayr, Johannes; Saßmannshausen, Heiner; Pillet, Pierre; Merkt, Frédéric

2014-11-01

239

Observation of dipole-quadrupole interaction in an ultracold gas of Rydberg atoms.  

PubMed

We observe the direct excitation of pairs of Cs atoms from the ground state to molecular states correlating asymptotically to nsn'f asymptotes. The molecular resonances are interpreted as originating from the dipole-quadrupole interaction between the nsn'f pair states and close-by npnp asymptotes (22?n?32). This interpretation is supported by Stark spectroscopy of the pair states and a detailed modeling of the interaction potentials. The dipole-quadrupole interaction mixes electronic states of opposite parity and, thus, requires a coupling between electronic and nuclear motion to conserve the total parity of the system. This non-Born-Oppenheimer coupling is facilitated by the near-degeneracy of even- and odd-L partial waves in the atom-atom scattering which have opposite parity. PMID:25415902

Deiglmayr, Johannes; Sassmannshausen, Heiner; Pillet, Pierre; Merkt, Frédéric

2014-11-01

240

Nuclear  

NSDL National Science Digital Library

What part does nuclear energy play in satisfying energy demands? This informational piece, part of a series about the future of energy, introduces students to the uranium atom as an energy source. Here students read about the history of nuclear energy, how energy is derived from uranium, and benefits of nuclear energy. Information is also provided about limitations, particularly disposal problems and radioactivity, and geographical considerations of nuclear power in the United States. Thought-provoking questions afford students chances to reflect on what they've read about the uses of nuclear power. Articles and information on new nuclear plant design and nuclear accidents are available from a sidebar. Five energy-related PBS NewsHour links are provided. A web link to the U.S. Nuclear Regulatory Commission is included. Copyright 2005 Eisenhower National Clearinghouse

Iowa Public Television. Explore More Project

2004-01-01

241

Is it possible to enhance the nuclear Schiff moment by nuclear collective modes?  

SciTech Connect

The nuclear Schiff moment is predicted to be enhanced in nuclei with static quadrupole and octupole deformation. The analogous suggestion of the enhanced contribution to the Schiff moment from the soft collective quadrupole and octupole vibrations in spherical nuclei is tested in the framework of the quasiparticle random phase approximation with separable quadrupole and octupole forces applied to the odd {sup 217-221}Ra and {sup 217-221}Rn isotopes. In this framework, we confirm the existence of the enhancement effect due to the soft modes, but only in the limit when the frequencies of quadrupole and octupole vibrations are close to zero.

Auerbach, N. [Tel Aviv University, School of Physics and Astronomy (Israel)], E-mail: auerbach@post.tau.ac.il; Dmitriev, V. F. [Budker Institute of Nuclear Physics (Russian Federation)], E-mail: v.f.dmitriev@inp.nsk.su; Flambaum, V. V. [University of New South Wales, School of Physics (Australia)], E-mail: flambaum@phys.unsw.edu.au; Lisetskiy, A. [GSI, Theory Department (Germany)], E-mail: olisetsk@theory.gsi.de; Sen'kov, R. A. [Budker Institute of Nuclear Physics (Russian Federation)], E-mail: senkov@nscl.msu.edu; Zelevinsky, V. G. [Michigan State University, National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy (United States)], E-mail: zelevins@nscl.msu.edu

2007-09-15

242

Photo nuclear data needed to understand mutli-MeV electrons behavior on the I.T.E.R. tokamak  

SciTech Connect

During early operation of the future tokamak ITER, electrons will be accelerated up to hundreds of MeV during unavoidable disruptions of the plasma current. As they impinge on the vacuum vessel, they will create high intensity X-ray beams, source of high activation spots by photo nuclear spallation reactions. To estimate beforehand the induced dose rates, a reliable set of cross sections is needed: reactions of X-rays (from 10 to 500 MeV) on a few usual materials. In addition, to characterize these electron beams on present day tokamaks, as Tore-Supra, additional data for some more exotic elements in a lower energy range (< 100 MeV) could be useful.

Joyer, P.; Martin, G. [CEN Cadarache, St. Paul-Lez-Durance (France)

1994-12-31

243

Explosives detection with quadrupole resonance analysis  

NASA Astrophysics Data System (ADS)

The increase in international terrorist activity over the past decade has necessitated the exploration of new technologies for the detection of plastic explosives. Quadrupole resonance analysis (QRA) has proven effective as a technique for detecting the presence of plastic, sheet, and military explosive compounds in small quantities, and can also be used to identify narcotics such as heroin and cocaine base. QRA is similar to the widely used magnetic resonance (MR) and magnetic resonance imaging (MRI) techniques, but has the considerable advantage that the item being inspected does not need to be immersed in a steady, homogeneous magnetic field. The target compounds are conclusively identified by their unique quadrupole resonance frequencies. Quantum magnetics has develop and introduced a product line of explosives and narcotics detection devices based upon QRA technology. The work presented here concerns a multi-compound QRA detection system designed to screen checked baggage, cargo, and sacks of mail at airports and other high-security facilities. The design philosophy and performance are discussed and supported by test results from field trials conducted in the United States and the United Kingdom. This detection system represents the current state of QRA technology for field use in both commercial and government sectors.

Rayner, Timothy J.; Thorson, Benjamin D.; Beevor, Simon; West, Rebecca; Krauss, Ronald A.

1997-02-01

244

Electrostatic quadrupole focused particle accelerating assembly with laminar flow beam  

DOEpatents

A charged particle accelerating assembly provided with a predetermined ratio of parametric structural characteristics and with related operating voltages applied to each of its linearly spaced focusing and accelerating quadrupoles, thereby to maintain a particle beam traversing the electrostatic fields of the quadrupoles in the assembly in an essentially laminar flow through the assembly.

Maschke, A.W.

1984-04-16

245

Second generation high gradient quadrupoles for the LHC interaction regions  

Microsoft Academic Search

Conceptual designs of large-aperture high-gradient Nb3Sn quadrupoles, suitable for use in a second generation LHC interaction region, are presented. A quadrupole with a 90 mm coil aperture and the same 200 T\\/m gradient as in the current LHC IR is technically feasible and would allow ?*=0.25 in to be achieved, doubling the LHC luminosity

T. Sen; J. Strait; A. V. Zlobin

2001-01-01

246

The LHC main dipoles and quadrupoles toward series production  

Microsoft Academic Search

The Large Hadron Collider (LHC) is under construction at CERN. Most of its 27 km underground tunnel will be filled with superconducting magnets, mainly 15 m long dipoles and 3.3 m long quadrupoles. In total 1248 dipole and 400 quadrupole magnets will be built (including spares), all wound with copper stabilized NbTi Rutherford cables and designed to operate in superfluid

Lucio Rossi

2003-01-01

247

Temperature dependent deuterium quadrupole coupling constants of short hydrogen bonds  

E-print Network

Temperature dependent deuterium quadrupole coupling constants of short hydrogen bonds Xingang Zhao January 2006 Abstract Very short hydrogen bonds universally show large positive dependences and intermode couplings. q 2006 Published by Elsevier B.V. Keywords: Hydrogen bonds; NMR; Deuterium quadrupole 1

Barsegov, Valeri

248

Performance of electromagnet and permanent magnet quadrupoles with iron poles  

Microsoft Academic Search

The largest field that can be obtained at the pole tip of an iron core quadrupole is limited by saturation in the iron and by its excitation by either the current density in the coil or the remanent field of the permanent magnet material. An analytical model is used to find the saturation limited performance of quadrupoles with either electromagnet

E. B. Blum; K. Halbach

1992-01-01

249

Computation of a quadrupole magnet for the APS storage ring  

SciTech Connect

The storage ring of the Advanced Photon Source will include 400 quadrupole magnets for focusing the beam. A prototype quadrupole has been designed, constructed, and measured. This paper describes the two- and three-dimensional (2-D and 3-D) field computations performed for this design. 2 refs., 6 figs., 1 tab.

Turner, L.R.; Kim, S.H.; Thompson, K.M.

1990-01-01

250

Nondestructive testing of adhesive bonds by nuclear quadrupole resonance method  

NASA Technical Reports Server (NTRS)

Inert, strain sensitive tracer, cuprous oxide, added to polymeric adhesive ensures sufficiently large signal to noise ratio in NQR system output. Method is successful, provided that RF-transparent structural materials are used between modified adhesive and probe of NQR spectrometer.

Hewitt, R. R.

1971-01-01

251

Development of a nuclear quadrupole based technique for  

E-print Network

, and for teaching me what real experimental physics is. A thank you from the bottom of my heart goes to the lab.1 TC/ TC max and Tg/ TC max vs. pm =pm-pm max . TC max is the maximum TC achievable 5 1.2 The electric)................................................................ 6 1.3 Basic ADNQR configuration. A sample (circle) with a preferred direction (marked by a line

Keren, Amit

252

Nuclear Quadrupole Resonance Zeeman Study of paraChlorophenol  

Microsoft Academic Search

The major field gradient directions for Cl in para-chlorophenol as determined by NQR and x-ray diffraction are compared quantitatively, and found to agree. The minor field gradient directions are examined qualitatively, and are consistent with those predicted on the basis of Cl&sngbnd;C partial double bonding. From a measurement of the field gradient asymmetry parameter &eegr;, the degree of chlorine—carbon double

G. E. Peterson; P. M. Bridenbaugh

1967-01-01

253

Deductions About Hybridization from Nuclear Quadrupole Coupling Constants  

Microsoft Academic Search

values, are B IB 2=1.79, B IBa=1.S0, B IB,=1.S5, B,Ba=1.71, BaB,= 1.S6, and B 2B2= 1.71A. The present agreement shows that R=~IIFol-IF,II\\/~ IFol =0.16 for the 144 observed reflections, which are 90 percent of the observable reflections on our photo­ graphs. Only boron atoms have been included so far in the calculations; no doubt inclusion of hydrogen atoms will decrease

Paul N. Schatz

1954-01-01

254

Application of nuclear quadrupole resonance in study of minerals  

Microsoft Academic Search

The NQR method has been used to study some structural and chemical properties of minerals that are difficult or impossible to determine by conventional methods. For example, an X-ray determination commonly integrates the data for all cells, whereas NQR can separate the nearly ideal from highly distorted ones. It can thus give a better picture of the ideal structure and

I. N. Penkov; I. A. Sofin

1967-01-01

255

Commissioning a Vibrating Wire System for Quadrupole Fiducialization  

SciTech Connect

Quadrupoles will be placed between the undulator segments in LCLS to keep the electron beam focused as it passes through. The quadrupoles will be assembled with their respective undulator segments prior to being placed into the tunnel. Beam alignment will be used to center the quadrupoles, along with the corresponding undulators, on the beam. If there is any displacement between the undulator and the quadrupole axes in the assemblies, the beam will deviate from the undulator axis. If it deviates by more than 80{micro}m in vertical or 140{micro}m in horizontal directions, the undulator will not perform as required by LCLS. This error is divided between three sources: undulator axis fiducialization, quadrupole magnetic axis fiducialization, and assembly of the two parts. In particular, it was calculated that the quadrupole needs to be fiducialized to within 25{micro}m in both vertical and horizontal directions. A previous study suggested using a vibrating wire system for finding the magnetic axis of the quadrupoles. The study showed that the method has high sensitivity (up to 1{micro}m) and laid out guidelines for constructing such a system. There are 3 steps in fiducializing the quadrupole with the vibrating wire system. They are positioning the wire at the magnet center (step 1), finding the wire with position detectors (step 2), and finding the quadrupole tooling ball positions relative to the position detector tooling balls (step 3). A previous study investigated the error associated with each step by using a permanent quadrupole magnet on an optical mover system. The study reported an error of 11{micro}m for step 1 and a repeatability of 4{micro}m for step 2. However, the set up used a FARO arm to measure tooling balls and didn't allow to accurately check step 2 for errors; an uncertainty of 100{micro}m was reported. Therefore, even though the repeatability was good, there was no way to check that the error in step 2 was small. Following the recommendations of that study, we used a CMM (Coordinate Measuring Machine) instead of the FARO arm for measuring the tooling balls. In addition, a roller cam positioner system replaced the optical movers for moving the quadrupole. With the exception of the quadrupole itself, the system was identical to what will be used in fiducializing the undulator quadrupoles. In this study, we investigate the new vibrating wire set up, including the error associated with each step of fiducialization. A vibrating wire system was constructed to fiducialize the quadrupoles between undulator segments in the LCLS. This note is a continuation of previous work to study the ability of the system to fulfill the fiducialization requirements.

Levashov, Michael Y

2010-12-03

256

Double-photoionization of helium including quadrupole radiation effects  

SciTech Connect

Non-perturbative time-dependent close-coupling calculations are carried out for the double photoionization of helium including both dipole and quadrupole radiation effects. At a photon energy of 800 eV, accessible at CUlTent synchrotron light sources, the quadrupole interaction contributes around 6% to the total integral double photoionization cross section. The pure quadrupole single energy differential cross section shows a local maxima at equal energy sharing, as opposed to the minimum found in the pure dipole single energy differential cross section. The sum of the pure dipole and pure quadrupole single energy differentials is insensitive to non-dipole effects at 800 eV. However, the triple differential cross section at equal energy sharing of the two ejected electrons shows strong non-dipole effects due to the quadrupole interaction that may be experimentally observable.

Colgan, James [Los Alamos National Laboratory; Ludlow, J A [AUBURN UNIV; Lee, Teck - Ghee [AUBURN UNIV; Pindzola, M S [AUBURN UNIV; Robicheaux, F [AUBURN UNIV

2009-01-01

257

An improved integrally formed radio frequency quadrupole  

DOEpatents

An improved radio frequency quadrupole is provided having an elongate housing with an elongate central axis and top, bottom and two side walls symmetrically disposed about the axis, and vanes formed integrally with the walls, the vanes each having a cross-section at right angles to the central axis which tapers inwardly toward the axis to form electrode tips spaced from each other by predetermined distances. Each of the four walls, and the vanes integral therewith, is a separate structural element having a central lengthwise plane passing through the tip of the vane, the walls having flat mounting surfaces at right angles to and parallel to the control plane, respectively, which are butted together to position the walls and vane tips relative to each other. 4 figs.

Abbott, S.R.

1987-10-05

258

Quadrupole resonance scanner for narcotics detection  

NASA Astrophysics Data System (ADS)

Interest in non-invasive, non-hazardous, bulk detection technologies for narcotics interdiction has risen over the last few years. As part of our continuing research and development programs in detection of narcotics and explosives using sensitive magnetic measuring devices, we present the first commercially available prototype Quadrupole Resonance (QR) scanner for narcotics detection. The portable narcotics detection system was designed in modular form such that a single QR base system could be easily used with a variety of custom detection heads. The QR system presented in this paper is suitable for scanning items up to 61 X 35 X 13 cm in size, and was designed to scan mail packages and briefcase-sized items for the presence of narcotics. System tests have shown that detection sensitivity is comparable that obtained in laboratory systems.

Shaw, Julian D.; Moeller, C. R.; Magnuson, Erik E.; Sheldon, Alan G.

1994-10-01

259

Radio-frequency quadrupole linear accelerator  

SciTech Connect

The radio-frequency quadrupole (RFQ) is a new linear accelerator concept in which rf electric fields are used to focus, bunch, and accelerate the beam. Because the RFQ can provide strong focusing at low velocities, it can capture a high-current dc ion beam from a low-voltage source and accelerate it to an energy of 1 MeV/nucleon within a distance of a few meters. A recent experimental test at the Los Alamos Scientific Laboratory (LASL) has confirmed the expected performance of this structure and has stimulated interest in a wide variety of applications. The general properties of the RFQ are reviewed and examples of applications of this new accelerator are presented.

Wangler, T.P.; Stokes, R.H.

1980-01-01

260

Roll measurement of Tevatron dipoles and quadrupoles  

SciTech Connect

In 2003 a simple digital level system was developed to allow for rapid roll measurements of all dipoles and quadrupoles in the Tevatron. The system uses a Mitutoyo digital level and a PC running MS WINDOWS XP and LAB VIEW to acquire data on the upstream and downstream roll of each magnet. The system is sufficiently simple that all 1,000 magnets in the Tevatron can be measured in less than 3 days. The data can be quickly processed allowing for correction of rolled magnets by the Fermilab alignment group. Data will be presented showing the state of the Tevatron in 2003 and the changes in rolls as measured in each shutdown since then.

Volk, J.T.; Elementi, L.; Gollwitzer, K.; Jostlein, H.; Nobrega, F.; Shiltsev, V.; Stefanski, R.

2006-09-01

261

Quadrupole collectivity in neutron-rich Cd isotopes  

NASA Astrophysics Data System (ADS)

The proximity to the closed shells at Z = 50 and N = 82 makes the neutron-rich Cd isotopes a perfect test case for nuclear theories. The energy of the first excited 2+-state in the even 122-128 shows an irregular behaviour as the Cd isotopes exhibit only a slight increase for 122Cd to 126Cd and even a decrease from 126Cd to 128Cd. This anomaly can so far not be reproduced by shell model calculations. Only beyond mean field calculations with a resultant prolate deformation are capable to describe this anomalous behaviour. In order to gain more information about the neutron-rich Cd isotopes a Coulomb excitation experiment was performed with MINIBALL at REX-ISOLDE, CERN. The extracted transition strengths B (E2,0+gs ? 2+1) for 122,124,126,128Cd agree with beyond mean field calculations. The spectroscopic quadrupole moments Qs (2+1) are compared with measurements on odd neutron-rich Cd isotopes.

Bönig, S.; Kröll, Th; Ilieva, S.; Scheck, M.; Is411; Is477; Is524; the Miniball collaborations

2015-02-01

262

Microwave spectrum, structural parameters, and quadrupole coupling for 1,2-dihydro-1,2-azaborine.  

PubMed

The first microwave spectrum for 1,2-dihydro-1,2-azaborine has been measured in the frequency range 7-18 GHz, providing accurate rotational constants and nitrogen and boron quadrupole coupling strengths for three isotopomers, H(6)C(4)(11)B(14)N, H(6)C(4)(10)B(14)N, and H(5)DC(4)(11)B(14)N. The measured rotational constants were used to accurately determine coordinates for the substituted atoms and provide sufficient data to determine most of the important structural parameters for this molecule. The spectra were obtained using a pulsed beam Fourier transform microwave spectrometer, with sufficient resolution to allow accurate measurements of (14)N, (11)B, and (10)B nuclear quadrupole hyperfine interactions. High-level ab initio calculations provided structural parameters and quadrupole coupling strengths that are in very good agreement with measured values. The rotational constants for the parent compound are A = 5657.335(1), B = 5349.2807(5), and C = 2749.1281(4) MHz, yielding the inertial defect Delta(0) = 0.02 amu x A(2) for the ground-state structure. The observed near-zero and positive inertial defect clearly indicates that the molecular structure of 1,2-dihydro-1,2-azaborine is planar. The least-squares fit analysis to determine the azaborine ring structure yielded the experimental bond lengths and 2sigma errors R(B-N) = 1.45(3) A, R(B-C) = 1.51(1) A, and R(N-C) = 1.37(3) A for the ground-state structure. Interbond angles for the ring were also determined. An extended Townes-Dailey population analysis of the boron and nitrogen quadrupole coupling constants provided the valence p-electron occupancy p(c) = 0.3e for boron and p(c) = 1.3e for nitrogen. PMID:20349985

Daly, Adam M; Tanjaroon, Chakree; Marwitz, Adam J V; Liu, Shih-Yuan; Kukolich, Stephen G

2010-04-21

263

Quadrupole beam-based alignment in the RHIC interaction regions  

SciTech Connect

Continued beam-based alignment (BBA) efforts have provided significant benefit to both heavy ion and polarized proton operations at RHIC. Recent studies demonstrated previously unknown systematic beam position monitor (BPM) offset errors and produced accurate measurements of individual BPM offsets in the experiment interaction regions. Here we describe the algorithm used to collect and analyze data during the 2010 and early 2011 RHIC runs and the results of these measurements. BBA data has been collected over the past two runs for all three of the active experimental IRs at RHIC, updating results from the 2005 run which were taken with incorrectly installed offsets. The technique was successfully applied to expose a systematic misuse of the BPM survey offsets in the control system. This is likely to benefit polarized proton operations as polarization transmission through acceleration ramps depends on RMS orbit control in the arcs, but a quantitative understanding of its impact is still under active investigation. Data taking is ongoing as are refinements to the BBA technique aimed at reducing systematic errors and properly accounting for dispersive effects. Further development may focus on non-triplet BPMs such as those located near snakes, or arc quadrupoles that do not have individually shunted power supplies (a prerequisite for the current method) and as such, will require a modified procedure.

Ziegler, J.; Satogata, T.

2011-03-28

264

Electronic coupling calculations with transition charges, dipoles, and quadrupoles derived from electrostatic potential fitting.  

PubMed

A transition charge, dipole, and quadrupole from electrostatic potential (TrESP-CDQ) method for electronic coupling calculations is proposed. The TrESP method is based on the classical description of electronic Coulomb interaction between transition densities for individual molecules. In the original TrESP method, only the transition charge interactions were considered as the electronic coupling. In the present study, the TrESP method is extended to include the contributions from the transition dipoles and quadrupoles as well as the transition charges. Hence, the self-consistent transition density is employed in the ESP fitting procedure. To check the accuracy of the present approach, several test calculations are performed to a helium dimer, a methane dimer, and an ethylene dimer. As a result, the TrESP-CDQ method gives a much improved description of the electronic coupling, compared with the original TrESP method. The calculated results also show that the self-consistent treatment to the transition densities contributes significantly to the accuracy of the electronic coupling calculations. Based on the successful description of the electronic coupling, the contributions to the electronic coupling are also analyzed. This analysis clearly shows a negligible contribution of the transition charge interaction to the electronic coupling. Hence, the distribution of the transition density is found to strongly influence the magnitudes of the transition charges, dipoles, and quadrupoles. The present approach is useful for analyzing and understanding the mechanism of excitation-energy transfer. PMID:25481127

Fujimoto, Kazuhiro J

2014-12-01

265

Toroidal quadrupole transitions associated to collective rotational-vibrational motions of the nucleus  

E-print Network

In the frame of the algebraic Riemann Rotational Model one computes the longitudinal, transverse and toroidal multipoles corresponding to the excitations of low-lying levels in the ground state band of several even-even nuclei by inelastic electron scattering (e,e'). Related to these transitions a new quantity, which accounts for the deviations from the Siegert theorem, is introduced. The intimate connection between the nuclear vorticity and the dynamic toroidal quadrupole moment is underlined. Inelastic differential cross-sections calculated at backscattering angles shows the dominancy of toroidal form-factors over a broad range of momentum transfer.

S. Misicu

1995-03-24

266

Toroidal quadrupole transitions associated to collective rotational-vibrational motions of the nucleus  

E-print Network

In the frame of the algebraic Riemann Rotational Model one computes the longitudinal, transverse and toroidal multipoles corresponding to the excitations of low-lying levels in the ground state band of several even-even nuclei by inelastic electron scattering (e,e'). Related to these transitions a new quantity, which accounts for the deviations from the Siegert theorem, is introduced. The intimate connection between the nuclear vorticity and the dynamic toroidal quadrupole moment is underlined. Inelastic differential cross-sections calculated at backscattering angles shows the dominancy of toroidal form-factors over a broad range of momentum transfer.

Misicu, S

1995-01-01

267

Development of Superconducting Focusing Quadrupoles for Heavy Ion Drivers  

SciTech Connect

Heavy Ion Fusion (HIF) is exploring a promising path to a practical inertial-confinement fusion reactor. The associated heavy ion driver will require a large number of focusing quadrupole magnets. A concept for a superconducting quadrupole array, using many simple racetrack coils, was developed at LLNL. Two, single-bore quadrupole prototypes of the same design, with distinctly different conductor, were designed, built, and tested. Both prototypes reached their short sample currents with little or no training. Magnet design, and test results, are presented and discussed.

Martovetsky, N; Manahan, R; Lietzke, A F

2001-09-10

268

Automated beam based alignment of the ALS quadrupoles  

SciTech Connect

Knowing the electrical offset of the storage ring beam position monitors (BPM) to an adjacent quadrupole magnetic center is important in order to correct the orbit in the ring. The authors describe a simple, fast and reliable technique to measure the BPM electrical centers relative to the quadrupole magnetic centers. By varying individual quadrupole magnets and observing the effects on the orbit they were able to measure the BPM offsets in half the horizontal and vertical BPMs (48) in the ALS. These offsets were measured to an accuracy of better than 50{mu}m. The technique is completely automated and takes less than 3 hours for the whole ring.

Portmann, G.; Robin, D.; Schachinger, L.

1995-04-01

269

Effects of nuclear structure on average angular momentum in subbarrier fusion  

E-print Network

We investigate the effects of nuclear quadrupole and hexadecapole couplings on the average angular momentum in sub-barrier fusion reactions. This quantity could provide a probe for nuclear shapes, distinguishing between prolate vs. oblate quadrupole and positive vs. negative hexadecapole couplings. We describe the data in the O + Sm system and discuss heavier systems where shape effects become more pronounced.

A. B. Balantekin; J. R. Bennett; S. Kuyucak

1994-07-21

270

Mechanical design of a second generation LHC IR quadrupole  

Microsoft Academic Search

One of the proposed options to increase the LHC luminosity is the replacement of the existing inner triplets at the interaction regions with new low-beta larger aperture quadrupoles operating at the same gradient. Lawrence Berkeley National Laboratory (LBNL) is carrying out preliminary studies of a large-bore Nb3Sn quadrupole. The mechanical design presents a support structure based on the use of

S. Caspi; S. E. Bartlett; D. R. Dietderich; P. Ferracin; S. A. Gourlay; R. R. Hafalia; C. R. Hannaford; A. F. Lietzke; A. D. McInturff; G. Sabbi; R. M. Scanlan

2004-01-01

271

Quadrupole hyperfine interaction in iron(III) dicarboxylic acid complexes  

Microsoft Academic Search

Mössbauer and infrared spectroscopic studies of a series of iron(III) complexes of dicarboxylic acids, maleic, malonic, succinic, glutaric, adipic, pimelic, suberic, azealic and sebacic have been carried out at room temperature. All complexes exhibit a quadrupole doublet with isomer shift () values in the range of 0.62 –0.72 mm·s–1 (with respect to SNP) and quadrupole splitting, EQ=0.53–0.74 mm· s–1. It

R. B. Lanjewar; A. M. Waditwar; A. N. Garg

1988-01-01

272

Development and Test of LARP Technological Quadrupole (TQC) Magnet  

Microsoft Academic Search

In support of the development of a large-aperture superconducting quadrupole for the Large Hadron Collider (LHC) luminosity upgrade, two-layer quadrupole models (TQC and TQS) with 90 mm aperture are being constructed at Fermilab and LBNL within the framework of the US LHC Accelerator Research Program (LARP). This paper describes the construction and test of model TQC01. ANSYS calculations of the

S. Feher; R. C. Bossert; G. Ambrosio; N. Andreev; E. Barzi; R. Carcagno; V. S. S. Kashikhin; V. V. V. Kashikhin; M. J. Lamm; F. Nobrega; I. Novitski; Yu. Pischalnikov; C. Sylvester; M. Tartaglia; D. Turrioni; G. Whitson; R. Yamada; A. V. Zlobin; S. Caspi; D. Dietderich; P. Ferracin; R. Hannaford; A. R. Hafalia; G. Sabbi

2007-01-01

273

Development and Test of TQC models, LARP Technological Quadrupole Magnets  

Microsoft Academic Search

In support of the development of a large-aperture Nb3Sn superconducting quadrupole for the Large Hadron Collider (LHC) luminosity upgrade, two-layer quadrupole models (TQC and TQS) with 90mm aperture are being constructed at Fermilab and LBNL within the framework of the US LHC Accelerator Research Program (LARP). This paper describes the development and test of TQC01b, the second TQC model, and

R. C. Bossert; G. Ambrosio; N. Andreev; E. Barzi; R. Carcagno; S. Feher; V. S. Kashikhin; V. V. Kashikhin; F. Nobrega; I. Novitski; D. Orris; M. Tartaglia; A. V. Zlobin; S. Caspi; D. Dietderich; P. Ferracin; A. R. Hafalia; G. Sabbi

2008-01-01

274

Thermal Analysis of the ILC Superconductin Quadrupole  

SciTech Connect

Critical to a particle accelerator's functioning, superconducting magnets serve to focus and aim the particle beam. The Stanford Linear Accelerator Center (SLAC) has received a prototype superconducting quadrupole designed and built by the Centro de Investigaciones Energ{acute e}ticas, Medioambientales y Tecnol{acute o}gicas (CIEMAT) to be evaluated for the International Linear Collider (ILC) project. To ensure proper functioning of the magnet, the device must be maintained at cryogenic temperatures by use of a cooling system containing liquid nitrogen and liquid helium. The cool down period of a low temperature cryostat is critical to the success of an experiment, especially a prototype setup such as this one. The magnet and the dewar each contain unique heat leaks and material properties. These differences can lead to tremendous thermal stresses. The system was analyzed mathematically, leading to ideal liquid helium and liquid nitrogen flow rates during the magnet's cool-down to 4.2 K, along with a reasonable estimate of how long this cool-down will take. With a flow rate of ten gaseous liters of liquid nitrogen per minute, the nitrogen shield will take approximately five hours to cool down to 77 K. With a gaseous helium flow rate of sixty liters per minute, the magnet will take at least nineteen hours to cool down to a temperature of 4.2 K.

Ross, Ian; /Rose-Hulman Inst., Terre Haute /SLAC

2006-09-13

275

Field measurement for large quadrupole magnets  

NASA Astrophysics Data System (ADS)

The results of the field measurement of the large quadrupole magnet of the MAGNEX spectrometer are presented and analyzed in the view of the possible application of modern techniques of ray reconstruction. The experimental data are checked against the symmetry conditions expected for the magnet. The observed deviations are related both to imperfections on the magnet manufacturing and to the not ideal positioning of the measurement device. In particular a quantitative estimation of the experimental error in the alignment of the probe with respect to the magnet is achieved. The measured field is also compared with the results from three-dimensional finite elements calculation. The obtained discrepancies between the measured and calculated field are too large for a direct application of the latter to ray-reconstruction methods. Nevertheless, these calculations are reliably used to study the impact of the observed inaccuracies in the probe alignment on the overall precision of field reconstruction and to set quantitative constraints on the field interpolation algorithms.

Lazzaro, A.; Cappuzzello, F.; Cunsolo, A.; Cavallaro, M.; Foti, A.; Orrigo, S. E. A.; Rodrigues, M. R. D.; Winfield, J. S.

2008-06-01

276

Quadrupole resonance spectroscopic study of narcotic materials  

NASA Astrophysics Data System (ADS)

Bulk narcotic detection systems based upon Quadrupole Resonance Analysis (QRA) technology have a major advantage over imaging technologies, in that QRA is chemical-specific and consequently has a lower rate of false alarms. QRA is a magnetic resonance technology which occurs as a result of the inherent molecular properties of the atomic nuclei in crystalline and amorphous solids. The QRA response is characterized by 1) the precessional frequency of the nucleus, and 2) the nature of the electric field gradient experienced by the nucleus,due to its molecular environment. Another important detection parameter is linewidth, resonant quality. All of these parameters depend on sample purity and manufacturing process. Quantum Magnetics recently carried out a study on the QRA signatures of various narcotic materials with the support of the US Army, US Customs, and the Office of National Drug Control Policy. The aim of the study was to fully characterize the variation in QRA spectroscopic parameters of different samples of cocaine base and cocaine hydrochloride. The results from this study ar discussed here.

Rayner, Timothy J.; West, Rebecca; Garroway, Allen N.; Lyndquist, R.; Yesinowski, James P.

1997-02-01

277

Suspending graphene using a quadrupole ion trap  

NASA Astrophysics Data System (ADS)

Creating a technology to suspend, manipulate, and probe an isolated graphene layer in vacuum may have applications ranging from new growth and fabrication strategies to fundamental measurements of these materials when they are completely uncoupled from a substrate. A sufficiently charged piece of graphene will remain flat due to electrostatic repulsion and can be confined using ac electric fields in a quadrupole trap. I will describe a trap built for this purpose which uses a design borrowed from atomic physics that is optimized for easy optical and physical access to the trapped particle [1]. Charged particles are injected into the trap using electrospray emission [2] of graphene suspended in organic solvents[3] and are probed with a 532 nm laser. I will provide details of the trap design and present preliminary data on characterization of the trapped graphene particles. [4pt] [1] Maiwald et al., Nature Physics 5, 551 (2009). [0pt] [2] Pearson et al., Phys. Rev. A 73, 032307 (2006). [0pt] [3] Hernandez et al., Nature Nanotechnology 3, 563 (2008).

Kane, Bruce

2010-03-01

278

Four-dimensional transverse beam matrix measurement using the multiple-quadrupole scan technique  

NASA Astrophysics Data System (ADS)

Accurate measurements of the transverse beam properties are essential to understand and optimize particle beams. We present an optimized method that uses three quadrupole magnets and one profile monitor to measure the full 4D transverse matrix of the beam. The method has been applied to the SwissFEL Injector Test Facility (SITF) at the Paul Scherrer Institute (Villigen). The SITF is the principal test bed and demonstration plant for the SwissFEL project, which aims at realizing a hard-x-ray free-electron laser in 2017. Simulations, measurements, and results of cross-plane coupling correction are presented.

Prat, Eduard; Aiba, Masamitsu

2014-05-01

279

Commissioning of helium injector for coupled radio frequency quadrupole and separated function radio frequency quadrupole accelerator  

SciTech Connect

A project to study a new type of acceleration structure has been launched at Peking University, in which a traditional radio frequency quadrupole (RFQ) and a separated function radio frequency quadrupole are coupled in one cavity to accelerate the He+ beam. A helium injector for this project is developed. The injector consists of a 2.45 GHz permanent magnet electron cyclotron resonance ion source and a 1.16 m long low energy beam transport (LEBT). The commissioning of this injector was carried out and an onsite test was held in June 2013. A 14 mA He+ beam with the energy of 30 keV has been delivered to the end of the LEBT, where a diaphragm with the diameter of 7 mm is located. The position of the diaphragm corresponds to the entrance of the RFQ electrodes. The beam emittance and fraction were measured after the 7 mm diaphragm. Its rms emittance is about 0.14 ??mm?mrad and the fraction of He+ is about 99%.

Peng, Shixiang, E-mail: sxpeng@pku.edu.cn; Chen, Jia; Ren, Haitao; Zhao, Jie; Xu, Yuan; Zhang, Tao; Xia, Wenlong; Gao, Shuli; Wang, Zhi; Luo, Yuting; Guo, Zhiyu [SKLNPT and IHIP, School of Physics, Peking University, Beijing 100871 (China)] [SKLNPT and IHIP, School of Physics, Peking University, Beijing 100871 (China); Zhang, Ailing; Chen, Jia'er [SKLNPT and IHIP, School of Physics, Peking University, Beijing 100871 (China) [SKLNPT and IHIP, School of Physics, Peking University, Beijing 100871 (China); University of Chinese Academy of Sciences, Beijing 100049 (China)

2014-02-15

280

Systematic Azimuth Quadrupole and Minijet Trends from Two-Particle Correlations in Heavy-Ion Collisions  

NASA Astrophysics Data System (ADS)

Heavy-ion collisions at the Relativistic Heavy Ion Collider (RHIC) produce a tremendous amount of data but new techniques are necessary for a comprehensive understanding of the physics behind these collisions. We present measurements from the STAR detector of both pt-integral and pt-differential azimuth two-particle correlations on azimuth (phi) and pseudorapidity (eta) for unidentified hadrons in Au-Au collisions at a center of mass energy = 62 and 200 GeV. The azimuth correlations can be fit to extract a quadrupole component--related to conventional v2 measures--and a same-side peak. The azimuth quadrupole component is distinguished from eta-localized same-side correlations by taking advantage of the full 2D eta and phi dependence. Both pt-integral and pt-differential results are presented as functions of Au-Au centrality. We observe simple universal energy and centrality trends for the pt-integral quadrupole component. pt-differential results can be transformed to reveal quadrupole pt spectra that are nearly independent of centrality. A parametrization of the pt-differential quadrupole shows a simple pt dependence that can be factorized from the centrality and collision energy dependence above 0.75 GeV/c. Angular correlations contain jet-like structure with most-probable hadron momentum 1 GeV/c. For better comparison to RHIC data we analyze the energy scale dependence of fragmentation functions from e+-e - collisions on rapidity y. We find that replotting fragmentation functions on a normalized rapidity variable results in a compact form precisely represented by the beta distribution, its two parameters varying slowly and simply with parton energy scale Q. The resulting parameterization enables extrapolation of fragmentation functions to low Q in order to describe fragment distributions at low transverse momentum ptin heavy ion collisions at RHIC. We convert minimum-bias jet-like angular correlations to single-particle hadron yields and compare them with parton fragment yields inferred from differential spectrum analysis (spectrum hard components). We find that jet-like correlations in central 200 GeV Au-Au collisions correspond quantitatively to pQCD predictions, and the jet-correlated hadron yield comprises one third of the Au-Au final state in central collisions.

Kettler, David

281

Quadrupole plasmon excitations in finite-size atomic chain systems  

NASA Astrophysics Data System (ADS)

The existence and the nature of a new mode of electronic collective excitations (quadrupole plasmons) in confined one-dimensional electronic systems, used to mimic finite-size linear metal atomic chains, have been predicted by an eigen-equation method. The eigen-equation based on the time-dependent density-functional theory is presented for calculating the collective excitations in confined systems. With this method, all modes of collective excitations in the 1D systems can be found out. These modes include dipole plasmons and quadrupole plasmons. The dipole plasmon mode corresponds to the antisymmetric oscillation of induced charge, and can be shown as a resonance of the dipole response. In the quadrupole plasmon modes, the induced charge distribution is symmetric, and the dipole response vanishes. The motion of the electrons in the quadrupole modes is similar to the vibration of atoms in the breathing mode of phonons. This type of plasmon can be shown as a resonance of the quadrupole response, and has to be excited by a non-uniform field.

Wu, Reng-lai; Xue, Hong-jie; Yu, Yabin

2014-12-01

282

Contribution of atom-probe tomography to a better understanding of glass alteration mechanisms: application to a nuclear glass specimen altered 25 years in a granitic environment  

SciTech Connect

We report and discuss results of atom probe tomography (APT) and energy-filtered transmission electron microscopy (EFTEM) applied to a borosilicate glass sample of nuclear interest altered for nearly 26 years at 90°C in a confined granitic medium in order to better understand the rate-limiting mechanisms under conditions representative of a deep geological repository for vitrified radioactive waste. The APT technique allows the 3D reconstruction of the elemental distribution at the reactive interphase with sub-nanometer precision. Profiles of the B distribution at pristine glass/hydrated glass interface obtained by different techniques are compared to show the challenge of accurate measurements of diffusion profiles at this buried interface on the nanometer length scale. Our results show that 1) Alkali from the glass and hydrogen from the solution exhibit anti-correlated 15 ± 3 nm wide gradients located between the pristine glass and the hydrated glass layer, 2) boron exhibits an unexpectedly sharp profile located just at the outside of the alkali/H interdiffusion layer; this sharp profile is more consistent with a dissolution front than a diffusion-controlled release of boron. The resulting apparent diffusion coefficients derived from the Li and H profiles are DLi = 1.5 × 10-22 m2.s-1 and DH = 6.8 × 10-23 m2.s-1. These values are around two orders of magnitude lower than those observed at the very beginning of the alteration process, which suggests that interdiffusion is slowed at high reaction progress by local conditions that could be related to the porous structure of the interphase. As a result, the accessibility of water to the pristine glass could be the rate-limiting step in these conditions. More generally, these findings strongly support the importance of interdiffusion coupled with hydrolysis reactions of the silicate network on the long-term dissolution rate, contrary to what has been suggested by recent interfacial dissolution-precipitation models for silicate minerals.

Gin, Stephane; Ryan, Joseph V.; Schreiber, Daniel K.; Neeway, James J.; Cabie, M.

2013-06-01

283

Entanglement, magnetic and quadrupole moments properties of the mixed spin Ising-Heisenberg diamond chain  

NASA Astrophysics Data System (ADS)

Thermal entanglement, magnetic and quadrupole moments properties of the mixed spin-1/2 and spin-1 Ising-Heisenberg model on a diamond chain are considered. Magnetization and quadrupole moment plateaus are observed for the antiferromagnetic couplings. Thermal negativity as a measure of quantum entanglement of the mixed spin system is calculated. Different behavior for the negativity is obtained for the various values of Heisenberg dipolar and quadrupole couplings. The intermediate plateau of the negativity has been observed at the absence of the single-ion anisotropy and quadrupole interaction term. When dipolar and quadrupole couplings are equal there is a similar behavior of negativity and quadrupole moment.

Abgaryan, V. S.; Ananikian, N. S.; Ananikyan, L. N.; Hovhannisyan, V.

2015-02-01

284

A microelectromechanical systems-enabled, miniature triple quadrupole mass spectrometer.  

PubMed

Miniaturized mass spectrometers are becoming increasingly capable, enabling the development of many novel field and laboratory applications. However, to date, triple quadrupole tandem mass spectrometers, the workhorses of quantitative analysis, have not been significantly reduced in size. Here, the basis of a field-deployable triple quadrupole is described. The key development is a highly miniaturized ion optical assembly in which a sequence of six microengineered components is employed to generate ions at atmospheric pressure, provide a vacuum interface, effect ion guiding, and perform fragmentation and mass analysis. Despite its small dimensions, the collision cell efficiently fragments precursor ions and yields product ion spectra that are very similar to those recorded using conventional instruments. The miniature triple quadrupole has been used to detect thiabendazole, a common pesticide, in apples at a level of 10 ng/g. PMID:25708099

Wright, Steven; Malcolm, Andrew; Wright, Christopher; O'Prey, Shane; Crichton, Edward; Dash, Neil; Moseley, Richard W; Zaczek, Wojciech; Edwards, Peter; Fussell, Richard J; Syms, Richard R A

2015-03-17

285

Enhanced quadrupole effects for atoms in optical vortices.  

PubMed

We show that the normally weak optical quadrupole interaction in atoms is enhanced significantly when the atom interacts at near resonance with an optical vortex. In particular, the forces and torque acting on the atom are shown here to scale up with the square of the winding number l of the vortex. Because the integer l can be arranged to be large, this property allows for processes involving dipole-forbidden, but quadrupole-allowed, transitions in atoms, such as cesium and oxygen, to come into play. We show that the mechanical effects of vortex light on atoms involving translational and rotational motion as well as trapping should be significantly enhanced for quadrupole transitions and present novel features with useful implications for the emerging field of atomtronics. PMID:23473140

Lembessis, V E; Babiker, M

2013-02-22

286

Variable-field permanent magnet quadrupole for the SSC  

SciTech Connect

A set of compact variable-field permanent-magnet quadrupoles have been designed, fabricated, and tested for use In the SSC linac matching section. The quadrupoles have 24 mm-diameter apertures and 40 mm-long poles. The hybrid (permanent-magnet and iron) design, uses a fixed core of magnet material (NdFeB) and iron (C-1006) surrounded by a rotating ring of the same magnet material and iron. The quadrupole gradient-length product can be smoothly varied from a minimum of 0.7 T up to a maximum, of 4.3 T by a 90{degrees} rotation of the outer ring of iron and magnet material.

Barlow, D.B.; Kraus, R.H. Jr.; Martinez, R.P.; Meyer, R.E.

1993-10-01

287

Space Charge Induced Nonlinear Effects in Quadrupole Ion Traps  

NASA Astrophysics Data System (ADS)

A theoretical method was proposed in this work to study space charge effects in quadrupole ion traps, including ion trapping, ion motion frequency shift, and nonlinear effects on ion trajectories. The spatial distributions of ion clouds within quadrupole ion traps were first modeled for both 3D and linear ion traps. It is found that the electric field generated by space charge can be expressed as a summation of even-order fields, such as quadrupole field, octopole field, etc. Ion trajectories were then solved using the harmonic balance method. Similar to high-order field effects, space charge will result in an "ocean wave" shape nonlinear resonance curve for an ion under a dipolar excitation. However, the nonlinear resonance curve will be totally shifted to lower frequencies and bend towards ion secular frequency as ion motion amplitude increases, which is just the opposite effect of any even-order field. Based on theoretical derivations, methods to reduce space charge effects were proposed.

Guo, Dan; Wang, Yuzhuo; Xiong, Xingchuang; Zhang, Hua; Zhang, Xiaohua; Yuan, Tao; Fang, Xiang; Xu, Wei

2014-03-01

288

Cryogen free superconducting splittable quadrupole magnet for linear accelerators  

SciTech Connect

A new superconducting quadrupole magnet for linear accelerators was fabricated at Fermilab. The magnet is designed to work inside a cryomodule in the space between SCRF cavities. SCRF cavities must be installed inside a very clean room adding issues to the magnet design, and fabrication. The designed magnet has a splittable along the vertical plane configuration and could be installed outside of the clean room around the beam pipe previously connected to neighboring cavities. For more convenient assembly and replacement a 'superferric' magnet configuration with four racetrack type coils was chosen. The magnet does not have a helium vessel and is conductively cooled from the cryomodule LHe supply pipe and a helium gas return pipe. The quadrupole generates 36 T integrated magnetic field gradient, has 600 mm effective length, and the peak gradient is 54 T/m. In this paper the quadrupole magnetic, mechanical, and thermal designs are presented, along with the magnet fabrication overview and first test results.

Kashikhin, V.S.; Andreev, N.; Kerby, J.; Orlov, Y.; Solyak, N.; Tartaglia, M.; Velev, G.; /Fermilab

2011-09-01

289

Advanced Hydrotest Facility (AHF) large bore quadrupole focusing magnet system  

SciTech Connect

The Advanced Hydrotest Facility (AHF) at Los Alamos will provide proton radiography of large-scale, dynamic events. The large bore (Case II) quadrupole focusing magnets are a subsystem in this facility, consisting of four complete imaging lines with a total of eight imaging plates and 52 quadrupole magnets. Each large bore quadrupole has an inner winding diameter of 660 mm and provides a gradient of 10.4 T/m with a 300 mm field of view. Each magnet is a two-layer saddle, contained by a three cm steel shell. The conductor is a Rutherford cable, soldered into a C-shaped copper channel. The magnets are cooled by the forced-flow of two-phase helium through coolant pipes. Since the winding must absorb bursts of 0.35 J/kg irradiation, both NbTi and Nb{sub 3}Sn designs are being considered.

Jason, A. J. (Andrew J.); Walstrom, P. L. (Peter L.); Waynert, J. A. (Joseph A.); Schultz, J. (Joel); Camille, R. J.; Antaya, T. (Thomas); Myatt, R. L.; Minervini, J.; Radovinsky, A.; Smith, B. A. (Brian A.)

2002-01-01

290

High and ulta-high gradient quadrupole magnets  

SciTech Connect

Small bore conventional dc quadrupoles with apertures from 1 to 2.578cm were designed and prototypes built and measured. New fabrication techniques including the use of wire electric discharge milling (EDM) to economically generate the pole tip contours and aperture tolerances are described. Magnetic measurement data from a prototype of a 1cm aperture quadrupole with possible use in future e/sup +//e/sup -/ super colliders are presented. At a current of 400A, the lens achieved a gradient of 2.475 T/cm, and had an efficiency of 76.6%.

Brunk, W.O.; Walz, D.R.

1985-05-01

291

High and ultra-high gradient quadrupole magnets  

NASA Astrophysics Data System (ADS)

Small bore conventional dc quadrupoles with apertures from 1 to 2.578 cm were designed and prototypes built and measured. New fabrication techniques including the use of wire electric discharge milling (EDM) to economically generate the pole tip contours and aperture tolerances are described. Magnetic measurement data from a prototype of a 1cm aperture quadrupole with possible use in future e(+)/e(-) super colliders are presented. At a current of 400A, the lens achieved a gradient of 2.475 T/cm, and had an efficiency of 76.6%.

Brunk, W. O.; Walz, D. R.

1985-05-01

292

High and ultra-high gradient quadrupole magnets  

SciTech Connect

Small bore conventional dc quadrupoles with apertures from 1 to 2.578cm were designed and prototypes built and measured. New fabrication techniques including the use of wire electric discharge milling (EDM) to economically generate the pole tip contours and aperture tolerances are described. Magnetic measurement data from a prototype of a 1cm aperture quadrupole with possible use in future e/sup +//e/sup -/ super colliders are presented. At a current of 400A, the lens achieved a gradient of 2.475 T/cm, and had an efficiency of 76.6%.

Walz, D.R.; Brunk, W.O.

1985-10-01

293

Measurement of the electric quadrupole moment of the 4d2D5/2 level in 88Sr+.  

PubMed

The quadrupole moment of the 4d (2)D(5/2) level in 88Sr+ has been measured to be 2.6(3)ea(2)(0), where a(0) is the Bohr radius and e the elementary charge. A single laser-cooled strontium ion was confined in an end cap trap with a variable dc quadrupole potential, and measurements were made on the 5s (2)S(1/2)-4d (2)D(5/2) transition at 674 nm using a femtosecond optical frequency comb. This work shows that measurements of the unperturbed 88Sr+ transition frequency with sub-Hz uncertainty are possible and is important in understanding the reproducibility of ion trap optical frequency standards. PMID:15524716

Barwood, G P; Margolis, H S; Huang, G; Gill, P; Klein, H A

2004-09-24

294

Understanding language  

E-print Network

My dissertation concerns the nature of linguistic understanding. A standard view about linguistic understanding is that it is a propositional knowledge state. The following is an instance of this view: given a speaker S ...

Pettit, Dean R. (Dean Reid), 1967-

2003-01-01

295

Understanding Carbohydrates  

MedlinePLUS

... Size: A A A Listen En Español Understanding Carbohydrates How much and what type of carbohydrate foods ... selecting the most nutrient dense choices. Explore: Understanding Carbohydrates Glycemic Index and Diabetes Learn about the glycemic ...

296

Collection understanding  

E-print Network

understanding. By presenting simple visual interfaces and intuitive methods of interacting with a collection, users come to understand the essence of the collection by focusing on the artifacts. This thesis discusses a practical approach for enhancing collection...

Chang, Michelle T.

2004-09-30

297

Nuclear Energy Level Argument for a Spheroidal Nuclear Model  

Microsoft Academic Search

Recently there has been notable success, particularly by Maria Mayer, in explaining many nuclear phenomena including spins, magnetic moments, isomeric states, etc. on the basis of a single particle model for the separate nucleons in a spherical nucleus. The spherical model, however, seems incapable of explaining the observed large quadrupole moments of nuclei. In this paper it is shown that

James Rainwater

1950-01-01

298

The feasibility of Quadrupole Dip Imaging with PMRI: focus on multiple sclerosis  

E-print Network

. Quadrupole Dip Imaging (QDI) is a novel MR technique based on the magnitude of the quadrupole dip in the T? dispersion profile of substances containing rotationally immobilized proteins. The implementation of QDI requires field-cycled (FC) relaxometry...

Jeter, Edward Hilton

2013-02-22

299

Nuclear Deformation Effects in the Cluster Radioactivity  

Microsoft Academic Search

We investigate the influence of the nuclear deformation on the decay rates of some cluster emission processes. The interaction between the daughter and the cluster is given by a double folding potential including quadrupole and hexadecupole deformed densities of both fragments. The nuclear part of the nucleus--nucleus interaction is density dependent and at small distances a repulsive core in the

Serban Misicu; Dan Protopopescu

1999-01-01

300

Furthering the understanding of silicate-substitution in ?-tricalcium phosphate: an X-ray diffraction, X-ray fluorescence and solid-state nuclear magnetic resonance study.  

PubMed

High-purity (SupT) and reagent-grade (ST), stoichiometric and silicate-containing ?-tricalcium phosphate (?-TCP: ST0/SupT0 and Si-TCP x=0.10: ST10/SupT10) were prepared by solid-state reaction based on the substitution mechanism Ca3(PO4)(2-x)(SiO4)x. Samples were determined to be phase pure by X-ray diffraction (XRD), and Rietveld analysis performed on the XRD data confirmed inclusion of Si in the ?-TCP structure as determined by increases in unit cell parameters; particularly marked increases in the b-axis and ?-angle were observed. X-ray fluorescence (XRF) confirmed the presence of expected levels of Si in Si-TCP compositions as well as significant levels of impurities (Mg, Al and Fe) present in all ST samples; SupT samples showed both expected levels of Si and a high degree of purity. Phosphorus ((31)P) magic-angle-spinning solid-state nuclear magnetic resonance (MAS NMR) measurements revealed that the high-purity reagents used in the synthesis of SupT0 can resolve the 12 expected peaks in the (31)P spectrum of ?-TCP compared to the low-purity ST0 that showed significant spectral line broadening; line broadening was also observed with the inclusion of Si which is indicative of induced structural disorder. Silicon ((29)Si) MAS NMR was also performed on both Si-TCP samples which revealed Q(0) species of Si with additional Si Q(1)/Q(2) species that may indicate a potential charge-balancing mechanism involving the inclusion of disilicate groups; additional Q(4) Si species were also observed, but only for ST10. Heating and cooling rates were briefly investigated by (31)P MAS NMR which showed no significant line broadening other than that associated with the emergence of ?-TCP which was only realised with the reagent-grade sample ST0. This study provides an insight into the structural effects of Si-substitution in ?-TCP and could provide a basis for understanding how substitution affects the physicochemical properties of the material. PMID:24287162

Duncan, J; Hayakawa, S; Osaka, A; MacDonald, J F; Hanna, J V; Skakle, J M S; Gibson, I R

2014-03-01

301

Progress of LHC low-? quadrupole magnets at KEK  

Microsoft Academic Search

Development of the LHC low-? insertion quadrupole magnet has been in progress at KEK since 1995 as a cooperative program between CERN and KEK. Five 1-m short model magnets have been fabricated and three of them have been tested. From the various test results of the first two models, the coil configuration was further optimized to reduce the higher magnetic

T. Shintomi; Y. Ajima; E. E. Burkhardt; T. Haruyama; N. Higashi; M. Iida; N. Kimura; S. Murai; T. Nakamoto; T. Ogitsu; H. Ohhata; N. Ohuchi; A. Orikasa; O. Osaki; R. J. M. Y. Ruber; K. Sugita; K. Tanaka; A. Terashima; K. Tsuchiya; A. Yamamoto; H. Yamaoka

2001-01-01

302

Status of the LHC inner triplet quadrupole program at Fermilab  

Microsoft Academic Search

Fermilab, in collaboration with LBNL and BNL, is developing a quadrupole for installation in the interaction region inner triplets of the LHC. This magnet is required to have an operating gradient of 215 T\\/m across a 70 mm coil bore, and operates in superfluid helium at 1.9 K. A 2 m magnet program addressing mechanical, magnetic, quench protection, and thermal

N. Andreev; T. Arkan; P. Bauer; R. Bossert; J. Brandt; J. Carson; S. Caspi; D. R. Chichili; L. Chiesa; C. Darve; J. Dimarco; S. Feher; A. Ghosh; H. Glass; Y. Huang; J. Kerby; M. Lamm; A. A. Markarov; A. D. McInturff; T. Nicol; A. Nobrega; I. Novitski; T. Ogitsu; D. Orris; J. P. Ozelis; T. Page; T. Peterson; R. Rabehl; W. Robotham; G. Sabbi; R. Scanlan; P. Schlabach; C. Sylvester; J. Strait; M. Tartaglia; J. C. Tompkins; G. Velev; S. Yadav; A. V. Zlobin

2001-01-01

303

Field alignment of quadrupole magnets for the LHC interaction regions  

Microsoft Academic Search

High-gradient superconducting quadrupole magnets are being developed by the US LHC Accelerator Project for the Interaction Regions of the Large Hadron Collider. Determination of the magnetic axis for alignment of these magnets will be performed using a single stretched wire system. These measurements will be done both at room and cryogenic temperatures with very long wire lengths, up to 20

J. DiMarco; H. Glass; M. J. Lamm; P. Schlabach; C. Sylvester; J. C. Tompkins; I. Krzywinski

2000-01-01

304

A LIGA Fabricated Quadrupole Array for Mass Spectroscopy  

NASA Technical Reports Server (NTRS)

A linear array of nine quadrupoles was fabricated using the LIGA process. Pole heights ranging from 1 to 3 mm were fabricated using synchrotron X-ray exposures to form free standing polymethylmethacrylate (PMMA) molds into which copper, gold or nickel were electroplated.

Jackson, K.; Wiberg, D. V.; Hecht, M. H.; Orient, O. J.; Chutjian, A.; Yee, K.; Fuerstenau, S.; Brennen, R. A.; Hruby, J.; Bonivert, W.

1997-01-01

305

LARP Long Quadrupole: A "Long" Step Toward an LHC  

ScienceCinema

The beginning of the development of Nb3Sn magnets for particle accelerators goes back to the 1960?s. But only very recently has this development begun to face the challenges of fabricating Nb3Sn magnets which can meet the requirements of modern particle accelerators. LARP (the LHC Accelerator Research Program) is leading this effort focusing on long models of the Interaction Region quadrupoles for a possible luminosity upgrade of the Large Hadron Collider. A major milestone in this development is to test, by the end of 2009, 4m-long quadrupole models, which will be the first Nb3Sn accelerator-type magnets approaching the length of real accelerator magnets. The Long Quadrupoles (LQ) are ?Proof-of-Principle? magnets which are to demonstrate that Nb3Sn technology is sufficiently mature for use in high energy particle accelerators. Their design is based on the LARP Technological Quadrupole (TQ) models, under development at FNAL and LBNL, which have design gradients higher than 200 T/m and an aperture of 90 mm. Several challenges must be addressed for the successful fabrication of long Nb3Sn coils and magnets. These challenges and the solutions adopted will be presented together with the main features of the LQ magnets. Several R&D lines are participating to this effort and their contributions will be also presented.

Giorgio Ambrosio

2010-01-08

306

On the exact solution of the harmonic quadrupole collective hamiltonian  

Microsoft Academic Search

Explicit expressions for the eigenfunctions of the harmonic quadrupole collective Hamiltonian both in the lab and intrinsic systems of references are given. Two alternative approaches, the technique of projective coherent states and the theory of harmonic polynomials in collective coordinates, are used. Symmetry properties and recursive formulae for the internally labelled wave functions are established. Applications to the yrast states

A. Gheorghe; A. A. Raduta; V. Ceausescu

1978-01-01

307

Particle Orbits in Quadrupole-Duodecapole Halo Suppressor  

NASA Astrophysics Data System (ADS)

Dynamics of continuous space-charged-dominated beam propagating through a periodic quadrupole-duodecapole focusing channel is studied both numerically and analytically using test-particle-core model and Particle-In-Cell (PIC) simulation code TOPOPIC. The results of TOPOPIC indicate that with initially matched beam, utilization of quadrupole-duodecapole channel results in less beam emittance growth and fewer halo particles than that in a pure quadrupole channel. The Poincare section of plot obtained from the test-particle-core model is used to systematically determine the beam intensity dependent resonant dominated behavior of the test-particles, which reveals the mechanism of the halo suppression in quadrupole-duodecapole channel. Results of study show that, for appropriate field strength, the nonlinear duodecapole force removes the resonant structures due to space charge. Motions of particles, originally trapped in the nonlinear resonant island or chaos region related to space charge, turn out to be along regular tori and these particles have less probability to get into beam halos.

Li, Chao; Xin, Qi; Yuan, He; Lei, Yang; Batygin, Y. K.

2015-01-01

308

Dodecahedral topology fails to explain quadrupole-octupole alignment  

E-print Network

The CMB quadrupole and octupole, as well as being weaker than expected, align suspiciously well with each other. Non-trivial spatial topology can explain the weakness. Might it also explain the alignment? The answer, at least in the case of the Poincare dodecahedral space, is a resounding no.

Jeff Weeks; Jesper Gundermann

2006-11-20

309

LARP Long Quadrupole: A "Long" Step Toward an LHC  

SciTech Connect

The beginning of the development of Nb3Sn magnets for particle accelerators goes back to the 1960’s. But only very recently has this development begun to face the challenges of fabricating Nb3Sn magnets which can meet the requirements of modern particle accelerators. LARP (the LHC Accelerator Research Program) is leading this effort focusing on long models of the Interaction Region quadrupoles for a possible luminosity upgrade of the Large Hadron Collider. A major milestone in this development is to test, by the end of 2009, 4m-long quadrupole models, which will be the first Nb3Sn accelerator-type magnets approaching the length of real accelerator magnets. The Long Quadrupoles (LQ) are “Proof-of-Principle” magnets which are to demonstrate that Nb3Sn technology is sufficiently mature for use in high energy particle accelerators. Their design is based on the LARP Technological Quadrupole (TQ) models, under development at FNAL and LBNL, which have design gradients higher than 200 T/m and an aperture of 90 mm. Several challenges must be addressed for the successful fabrication of long Nb3Sn coils and magnets. These challenges and the solutions adopted will be presented together with the main features of the LQ magnets. Several R&D lines are participating to this effort and their contributions will be also presented.

Giorgio Ambrosio

2008-02-13

310

Design and fabrication of the prototype superconducting quadrupole for the CERN LHC project  

Microsoft Academic Search

Within the framework of the LHC (Large Hadron Collider) R&D program, CERN and CEA\\/Saclay have established a collaboration to carry out the design, building and testing of a superconducting LHC prototype quadrupole at the Saclay laboratory. The cold mass of this quadrupole is presently under construction at Saclay. The quadrupole design features a twin aperture configuration, a gradient of 250

J. M. Baze; D. Cacaut; M. Chapman; J. P. Jacquemin; C. Lyraud; C. Michez; Y. Pabot; J. Perot; J. M. Rifflet; J. C. Toussaint; P. Vedrine; R. Perin; N. Siegel; T. Tortschanoff

1992-01-01

311

Magnetic and Mechanical Analysis of the HQ Model Quadrupole Designs for LARP  

Microsoft Academic Search

Insertion quadrupoles with large bore and high gradient are required to upgrade the luminosity of the large hadron collider (LHC). The US LHC accelerator research program is developing Nb3Sn technology for the upgrade. This effort includes a series of 1 m long technology quadrupoles (TQ), to demonstrate the reproducibility at moderate field, and high-gradient quadrupoles (HQ) to explore the magnet

Helene Felice; Shlomo Caspi; Paolo Ferracin; Vadim Kashikhin; Igor Novitski; Gianluca Sabbi; Alexander Zlobin

2008-01-01

312

INVESTIGATION OF BORIDES OF TRANSITION METALS AND PURE BORON BY THE METHOD OF NUCLEAR MAGNETIC RESONANCE  

Microsoft Academic Search

The method of nuclear magnetic resonance was used to investigate ; diborides of TiC, Zr, Nb, Ta, Cr, and MOâBâ in which quadrupole ; effects of the first and second orders were discovered. The constants of ; quadrupole binding were found. The same constarts were computed under the ; assumption that boron atoms possess hybridized spd⁴ orbits that affect the

O. T. Malyuchkov; V. A. Povitskii

1962-01-01

313

Understanding the cause of an unreadable nuclear medicine image: a case of unexpected results with 123I whole-body scintigraphy.  

PubMed

When unexpected results are obtained with standard image collection, the nuclear medicine physician must consider many technical factors that may have contributed. When image quality is poor, prior radiotracer administration, among other things, should always be considered. Our case demonstrates how knowledge of patient history and basic principles of nuclear medicine physics allows recognition of the septal penetration artifact. This allows the nuclear medicine physician to tailor the exam to an individual patient and obtain the most useful diagnostic information for the clinician. PMID:25168251

Skweres, Justin; Yang, Zhiyun; Gonzalez-Toledo, Eduardo

2014-12-01

314

Level lifetimes and quadrupole moments from Coulomb excitation in the Ba chain and the N = 80 isotones  

NASA Astrophysics Data System (ADS)

The chain of Barium isotopes enables us to study experimentally the evolution of nuclear quadrupole collectivity from the shell closure at N = 82 towards neutron-deficient or neutron-rich deformed nuclei. The TU Darmstadt group has investigated several nuclei from stable 130,132Ba up to radioactive 140,142Ba with the projectile-Coulomb excitation technique including the use of the Doppler-shift attenuation method (DSAM). Lifetimes of quadrupole-collective states of 132Ba and 140Ba were obtained for the first time as well as the static electric quadrupole moments Q(21+) for 130,132Ba and 140,142Ba. The results are compared to Monte Carlo shell model and Beyond-Mean-Field calculations. The phenomenon of shell stabilization in the N = 80 isotones is further investigated by measurements of the B(E2;21+ ? 01+) values of 140Nd and 142Sm and comparison to the quasi-particle phonon model and shell-model calculations.

Bauer, C.; Guastalla, G.; Leske, J.; Möller, O.; Möller, T.; Pakarinen, J.; Pietralla, N.; Rainovski, G.; Rapisarda, E.; Seweryniak, D.; Stahl, C.; Stegmann, R.; Wiederhold, J.; Zhu, S.

2012-12-01

315

Temperature dependences of the 39K and 85Rb quadrupole coupling constants in paraelectric KH2PO4, KH2AsO4, RbH2PO4, and RbH2AsO4  

NASA Astrophysics Data System (ADS)

Temperature dependences of 39K and 85Rb nuclear-quadrupole resonance frequencies have been measured in tetragonal paraelectric phases of KH2PO4, KH2AsO4, RbH2PO4, and RbH2AsO4. The measured quadrupole coupling constants are compared to the quadrupole coupling constants calculated in a point-charge model in which a cation bears a positive charge e whereas the negative charge -e of a PO-4 or AsO-4 ion is, in a time average, equally shared by the four oxygen atoms. The influence of the anisotropic thermal expansion of the crystal lattices on the temperature dependence of the quadrupole coupling constants is calculated in the same model. Both the calculated and measured quadrupole coupling constants as well as the calculated and measured temperature coefficients of the quadrupole coupling constants agree within the experimental error. Thus the ``antiferroelectric'' Slater configurations of the H2PO4 and of the H2AsO4 groups which seem to have a strong influence on the 75As NQR frequencies in the tetragonal paraelectric phase are of a local nature and they have nearly no influence on the potassium and rubidium NQR frequencies.

Seliger, J.; Žagar, V.

1994-06-01

316

SP(6,R) Symmetry and the Giant Quadrupole Resonance in MAGNESIUM-24.  

NASA Astrophysics Data System (ADS)

Microscopic nuclear calculations are approached by partitioning the many-nucleon Hilbert space as a direct sum of symplectic bands. Computational techniques and algorithms which utilize commutator methods, and which are more powerful than the more straight-forward purely shell-model approach, are developed for calculating the matrix elements of two-body operators within such an Sp(6,R) (R-HOOK) U(3) symmetry-adapted basis. These techniques may be generalized to n-body operators of any n. These computational tools are applied to the study of the Giant Quadrupole Resonance in ('24)Mg: the final calculation presented uses a microscopic Hamiltonian consisting of the kinetic energy plus the semi-realistic two-body Brink -Boeker B1 potential within a space consisting of three symplectic bands up to 6(H/2PI)(omega) total excitation.

Reske, Edward John

1984-06-01

317

Observation of the 717-nm electric quadrupole transition in triply charged thorium  

NASA Astrophysics Data System (ADS)

We excite the 717-nm electric quadrupole 6D3/2 ? 7S1/2 transition in a laser-cooled 232Th3+ ion crystal. The transition frequency and the lifetime of the metastable 7S1/2 level are measured to be 417 845 964(30) MHz and 0.60(7) s, respectively. We subsequently employ the 7S1/2 level to drive the ions with nanosecond-long 269-nm laser pulses into the 7P1/2 level. The latter is connected to the 7S1/2 electronic level within the 229Th nuclear isomer manifold by the strongest available electron-bridge transition, forming a basis for its laser excitation.

Radnaev, A. G.; Campbell, C. J.; Kuzmich, A.

2012-12-01

318

Significance of the Lattice Contribution to Mössbauer Quadrupole Splitting: ReEvaluation of the Fe57m Nuclear Quadrupole Moment  

Microsoft Academic Search

We have considered in detail the lattice contribution to the electric-field gradient at the Fe57 nucleus in several ferrous compounds. Using x-ray crystallographic data and a high-speed computer, direct lattice-sum calculations have been carried out for FeSiF6.6H2O, FeSO4.7H2O, FeCl2.4H2O, and FeCl2.2H2O, yielding the magnitudes and signs of the lattice effect in these compounds. The results obtained ranged from negligible to

Arthur J. Nozik; Morton Kaplan

1967-01-01

319

Understanding Waves  

NSDL National Science Digital Library

Understanding Waves is a graduate-level professional development course designed to enhance your understanding and teaching of physical science. In two sessions, you will investigate physical science topics using hands-on activities and online resources including video segments, interactive activities, readings, and other multimedia materials. These resources are drawn from Teachers' Domain, WGBH's digital library service.

2010-01-01

320

Simulation of direct plasma injection for laser ion beam acceleration with a radio frequency quadrupole  

SciTech Connect

The direct plasma injection scheme (DPIS) has been being studied at Institute of Modern Physics since several years ago. A C{sup 6+} beam with peak current of 13 mA, energy of 593 keV/u has been successfully achieved after acceleration with DPIS method. To understand the process of DPIS, some simulations have been done as follows. First, with the total current intensity and the relative yields of different charge states for carbon ions measured at the different distance from the target, the absolute current intensities and time-dependences for different charge states are scaled to the exit of the laser ion source in the DPIS. Then with these derived values as the input parameters, the extraction of carbon beam from the laser ion source to the radio frequency quadrupole with DPIS is simulated, which is well agreed with the experiment results.

Jin, Q. Y.; Li, Zh. M.; Liu, W. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); School of Physics, University of Chinese Academy of Sciences, Beijing 100049 (China); Zhao, H. Y., E-mail: zhaohy@impcas.ac.cn; Zhang, J. J.; Sha, Sh.; Zhang, Zh. L.; Zhang, X. Zh.; Sun, L. T.; Zhao, H. W. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

2014-07-15

321

Understanding Flu  

MedlinePLUS

... Bonny McClain Whether the topic is seasonal influenza, bird flu or something called a pandemic, everyone seems ... make sure you understand all the talk about bird (avian) flu and pandemics. The flu season in ...

322

Understanding Malaria  

MedlinePLUS

... JavaScript on. Read more information on enabling JavaScript. Malaria Skip Content Marketing Share this: Main Content Area Understanding Malaria Quick Facts Cause Transmission Symptoms Diagnosis Treatment Prevention ...

323

Understanding Sarcoidosis  

MedlinePLUS

... Register for ENews Home > Lung Disease > Sarcoidosis Understanding Sarcoidosis Sarcoidosis is a disease caused by inflammation. Scientists ... pain, or shortness of breath. How Serious Is Sarcoidosis? Nobody can predict how sarcoidosis will affect one ...

324

Understanding Nano  

NSDL National Science Digital Library

Nanotechnology can be a complicated topic. The Understanding Nano website is dedicated to providing clear and concise explanations of nanotechnology applications along with information on companies working in each area.

325

Nb3Sn Quadrupoles Designs For The LHC Upgrades  

SciTech Connect

In preparation for the LHC luminosity upgrades, high field and large aperture Nb{sub 3}Sn quadrupoles are being studied. This development has to incorporate all the relevant features for an accelerator magnet like alignment and cooling channels. The LARP HQ model is a high field and large bore quadrupole that will meet these requirements. The 2-layer coils are surrounded by a structure based on key and bladder technology with supporting iron yoke and aluminum shell. This structure is aimed at pre-stress control, alignment and field quality. We present here the magnetic and mechanical design of HQ, along with recent progress on the development of the first 1-meter model.

Felice, Helene

2008-05-19

326

Development and Test of TQC models, LARP Technological Quadrupole Magnets  

SciTech Connect

In support of the development of a large-aperture Nb3Sn superconducting quadrupole for the Large Hadron Collider (LHC) luminosity upgrade, two-layer quadrupole models (TQC and TQS) with 90mm aperture are being constructed at Fermilab and LBNL within the framework of the US LHC Accelerator Research Program (LARP). This paper describes the development and test of TQC01b, the second TQC model, and the experience during construction of TQE02 and TQC02, subsequent models in the series. ANSYS analysis of the mechanical structure, its underlying assumptions, and changes based on experience with TQC01 are presented and discussed. Construction experience, in-process measurements, and modifications to the assembly since TQC01 are described. The test results presented here include magnet strain and quench performance during training of TQC01b, as well as quench studies of current ramp rate dependence.

Bossert, R.C.; Ambrosio, G.; Andreev, N.; Barzi, E.; Carcagno, R.; Feher, S.; Kashikhin, V.S.; Kashikhin, V.V.; Nobrega, F.; Novitski, I.; Orris, D.; Tartaglia, M.; Zlobin, A.V.; Caspi, S.; Dietderich, D.; Ferracin, P.; Hafalia, A.R.; Sabbi, G.

2008-06-01

327

Development and test of LARP technological quadrupole (TQC) magnet  

SciTech Connect

In support of the development of a large-aperture Nb{sub 3}Sn superconducting quadrupole for the Large Hadron Collider (LHC) luminosity upgrade, two-layer quadrupole models (TQC and TQS) with 90-mm aperture are being constructed at Fermilab and LBNL within the framework of the US LHC Accelerator Research Program (LARP). This paper describes the construction and test of model TQC01. ANSYS calculations of the structure are compared with measurements during construction. Fabrication experience is described and in-process measurements are reported. Test results at 4.5K are presented, including magnet training, current ramp rate studies and magnet quench current . Results of magnetic measurements at helium temperature are also presented.

Feher, S.; Bossert, R.C.; Ambrosio, G.; Andreev, N.; Barzi, E.; Carcagno, R.; Kashikhin, V.S.; Kashikhin, V.V.; Lamm, M.J.; Nobrega, F.; Novitski, I.; /Fermilab /LBL, Berkeley

2006-08-01

328

Diabatization based on the dipole and quadrupole: The DQ method  

SciTech Connect

In this work, we present a method, called the DQ scheme (where D and Q stand for dipole and quadrupole, respectively), for transforming a set of adiabatic electronic states to diabatic states by using the dipole and quadrupole moments to determine the transformation coefficients. It is more broadly applicable than methods based only on the dipole moment; for example, it is not restricted to electron transfer reactions, and it works with any electronic structure method and for molecules with and without symmetry, and it is convenient in not requiring orbital transformations. We illustrate this method by prototype applications to two cases, LiH and phenol, for which we compare the results to those obtained by the fourfold-way diabatization scheme.

Hoyer, Chad E.; Xu, Xuefei; Ma, Dongxia; Gagliardi, Laura, E-mail: gagliard@umn.edu, E-mail: truhlar@umn.edu; Truhlar, Donald G., E-mail: gagliard@umn.edu, E-mail: truhlar@umn.edu [Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota, 207 Pleasant St. SE, Minneapolis, Minnesota 55455-0431 (United States)

2014-09-21

329

120-mm supercondcting quadrupole for interaction regions of hadron colliders  

SciTech Connect

Magnetic and mechanical designs of a Nb{sub 3}Sn quadrupole magnet with 120-mm aperture suitable for interaction regions of hadron colliders are presented. The magnet is based on a two-layer shell-type coil and a cold iron yoke. Special spacers made of a low-Z material are implemented in the coil mid-planes to reduce the level of radiation heat deposition and radiation dose in the coil. The quadrupole mechanical structure is based on aluminum collars supported by an iron yoke and a stainless steel skin. Magnet parameters including maximum field gradient and field harmonics, Nb3Sn coil pre-stress and protection at the operating temperatures of 4.5 and 1.9 K are reported. The level and distribution of radiation heat deposition in the coil and other magnet components are discussed.

Zlobin, A.V.; Kashikhin, V.V.; Mokhov, N.V.; Novitski, I.; /Fermilab

2010-05-01

330

Performance of An Adjustable Strength Permanent Magnet Quadrupole  

SciTech Connect

An adjustable strength permanent magnet quadrupole suitable for use in Next Linear Collider has been built and tested. The pole length is 42cm, aperture diameter 13mm, peak pole tip strength 1.03Tesla and peak integrated gradient * length (GL) is 68.7 Tesla. This paper describes measurements of strength, magnetic CL and field quality made using an air bearing rotating coil system. The magnetic CL stability during -20% strength adjustment proposed for beam based alignment was < 0.2 microns. Strength hysteresis was negligible. Thermal expansion of quadrupole and measurement parts caused a repeatable and easily compensated change in the vertical magnetic CL. Calibration procedures as well as CL measurements made over a wider tuning range of 100% to 20% in strength useful for a wide range of applications will be described. The impact of eddy currents in the steel poles on the magnetic field during strength adjustments will be reported.

Gottschalk, S.C.; DeHart, T.E.; Kangas, K.W.; /STI Optronics, Bellevue; Spencer, C.M.; /SLAC; Volk, J.T.; /Fermilab

2006-03-01

331

Diabatization based on the dipole and quadrupole: The DQ method  

NASA Astrophysics Data System (ADS)

In this work, we present a method, called the DQ scheme (where D and Q stand for dipole and quadrupole, respectively), for transforming a set of adiabatic electronic states to diabatic states by using the dipole and quadrupole moments to determine the transformation coefficients. It is more broadly applicable than methods based only on the dipole moment; for example, it is not restricted to electron transfer reactions, and it works with any electronic structure method and for molecules with and without symmetry, and it is convenient in not requiring orbital transformations. We illustrate this method by prototype applications to two cases, LiH and phenol, for which we compare the results to those obtained by the fourfold-way diabatization scheme.

Hoyer, Chad E.; Xu, Xuefei; Ma, Dongxia; Gagliardi, Laura; Truhlar, Donald G.

2014-09-01

332

The development of compact magnetic quadrupoles for ILSE  

SciTech Connect

Magnetic focussing is selected for the 4 MeV to 10 MeV section of the Induction Linac Systems Experiments (ILSE) to study the transport of magnetically focussed spacecharge-dominated beams and to explore the engineering problems in accurate positioning of the magnetic fields in an array of quadrupoles. A prototype development program for such magnets is currently under way. A compact design was selected to decrease the overall accelerator diameter and its cost. The design evolved from a cosine 2{theta} current distribution, corrected for end effects. Current-dominated magnets are used in a pulsed mode to allow higher current densities compared to standard dc water-cooled conductors. The POISSON and MAFCO codes were used in the design of the magnets. The construction of the quadrupoles is aimed at achieving location accuracy of the magnetic center to within 1 mil (2.54 {times} 10{sup {minus}5} m) of the mechanical center.

Faltens, A.; Mukherjee, S.; Brady, V.

1990-08-01

333

Development and Test of LARP Technological Quadrupole (TQC) Magnet  

SciTech Connect

In support of the development of a large-aperture Nb{sub 3}Sn superconducting quadrupole for the Large Hadron Collider (LHC) luminosity upgrade, two-layer quadrupole models (TQC and TQS) with 90 mm aperture are being constructed at Fermilab and LBNL within the framework of the US LHC Accelerator Research Program (LARP). This paper describes the construction and test of model TQC01. ANSYS calculations of the structure are compared with measurements during construction. Fabrication experience is described and in-process measurements are reported. Test results at 4.5 K are presented, including magnet training, current ramp rate studies and magnet quench current. Results of magnetic measurements at helium temperature are also presented.

Feher, S.; Bossert, R.C.; Ambrosio, G.; Andreev, N.; Barzi, E.; Carcagno, R.; Kashikhin, V.S.; Kashikhin, V.V.; Lamm, M.J.; Nobrega, F.; Novitski, I.; Pischalnikov, Yu.; Sylvester, C.; Tartaglia, M.; Turrioni, D.; Whitson, G.; Yamada, R.; Zlobin, A.V.; Caspi, S.; Dietderich, D.; Ferracin, P.; Hannaford, R.; Hafalia, A.R.; Sabbi, G.

2007-06-01

334

Superconducting Quadrupole Doublet for the Los Alamos Meson Physics Facility  

Microsoft Academic Search

A superconducting quadrupole doublet for beam focusing has been operated with a 30-kG field at the center of the 30-cm-long straight section of the magnets and a 3-kG?cm field gradient. The magnets used twisted multifilament Nb&sngbnd;Ti superconductor imbedded in a Cu matrix of 0.050-in. diameter and operate at currents up to 500 A. Each magnet is equipped with a persistent

J. D. Rogers; W. V. Hassenzahl; H. L. Laquer; J. K. Novak; R. W. Stokes

1971-01-01

335

Magnetic field programming in quadrupole magnetic field-flow fractionation  

NASA Astrophysics Data System (ADS)

Magnetic field-flow fractionation (MgFFF) is a technique for the separation and characterization of magnetic nanoparticles. It is explained that the analysis of polydisperse samples requires a programmed decay of field and field gradient during sample elution. A procedure for achieving reproducible field decay with asymptotic approach to zero field using a quadrupole electromagnet is described. An example of an analysis of a polydisperse sample under programmed field decay is given.

Stephen Williams, P.; Carpino, Francesca; Moore, Lee R.; Zborowski, Maciej

336

Levitated spinning graphene flakes in an electric quadrupole ion trap  

Microsoft Academic Search

A method is described for levitating micron-sized few-layer graphene flakes in an electric quadrupole ion trap. Starting from a liquid suspension containing graphene, charged flakes are injected into the trap using the electrospray ionization technique and are probed optically. At micro-torr pressures, torques from circularly polarized light cause the levitated particles to rotate at frequencies >1MHz , which can be

B. E. Kane

2010-01-01

337

NORMAL CONDUCTING QN QUADRUPOLE FOR THE HERA LUMINOSITY UPGRADE  

Microsoft Academic Search

The magnet QN is a septum quadrupole with a narrow septum coil for focusing the protons with a gradient of 30T\\/m, needed for the HERA Luminosity upgrade (1). It is 1.93m long and has a pole radius of 35mm. The field error must be limited to 3*10 -4 at 25mm reference radius over the whole excitation range of Gmax=20 Gmin.

E. Bondarchuk; N. Doinikov; B. Kitaev; V. Korshakov; V. Krasnoperov; V. Lokiev; N. Maximenkova; V. Muratov; A. Nikiforovski; A. Simakov; K. Sinram; F. Willeke; G. Woebke

338

MEASURING LOCAL GRADIENT AND SKEW QUADRUPOLE ERRORS IN RHIC IRS.  

SciTech Connect

The measurement of local linear errors at RHIC interaction regions using an ''action and phase'' analysis of difference orbits has already been presented. This paper evaluates the accuracy of this technique using difference orbits that were taken when known gradient errors and skew quadrupole errors were intentionally introduced. It also presents action and phase analysis of simulated orbits when controlled errors are intentionally placed in a RHIC simulation model.

CARDONA,J.; PEGGS,S.; PILAT,R.; PTITSYN,V.

2004-07-05

339

CMB quadrupole suppression. II. The early fast roll stage  

SciTech Connect

Within the effective field theory of inflation, an initialization of the classical dynamics of the inflaton with approximate equipartition between the kinetic and potential energy of the inflaton leads to a brief fast roll stage that precedes the slow roll regime. The fast roll stage leads to an attractive potential in the wave equations for the mode functions of curvature and tensor perturbations. The evolution of the inflationary perturbations is equivalent to the scattering by this potential and a useful dictionary between the scattering data and observables is established. Implementing methods from scattering theory we prove that this attractive potential leads to a suppression of the quadrupole moment for CMB and B-mode angular power spectra. The scale of the potential is determined by the Hubble parameter during slow roll. Within the effective field theory of inflation at the grand unification (GUT) energy scale we find that if inflation lasts a total number of e-folds N{sub tot}{approx}59, there is a 10%-20% suppression of the CMB quadrupole and about 2%-4% suppression of the tensor quadrupole. The suppression of higher multipoles is smaller, falling off as 1/l{sup 2}. The suppression is much smaller for N{sub tot}>59, therefore if the observable suppression originates in the fast roll stage, there is the upper bound N{sub tot}{approx}59.

Boyanovsky, D.; Vega, H. J. de [Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States); Observatoire de Paris, LERMA, Laboratoire Associe au CNRS UMR 8112, 61, Avenue de l'Observatoire, 75014 Paris (France); LPTHE, Universite Pierre et Marie Curie (Paris VI) et Denis Diderot (Paris VII), Laboratoire Associe au CNRS UMR 7589, Tour 24, 5eme. etage, 4, Place Jussieu, 75252 Paris, Cedex 05 (France); Sanchez, N. G. [Observatoire de Paris, LERMA, Laboratoire Associe au CNRS UMR 8112, 61, Avenue de l'Observatoire, 75014 Paris (France)

2006-12-15

340

Transverse beam emittance measurement using quadrupole variation at KIRAMS-430  

NASA Astrophysics Data System (ADS)

In order to produce a 430 MeV/u carbon ion (12 C 6+) beam for medical therapy, the Korea Institute of Radiological & Medical Sciences (KIRAMS) has carried out the development of a superconducting isochronous cyclotron, the KIRAMS-430. At the extraction of the cyclotron, an Energy Selection System (ESS) is located to modulate the fixed beam energy and to drive the ion beam through High Energy Beam Transport (HEBT) into the treatment room. The beam emittance at the ion beamline is to be measured to provide information on designing a beam with high quality. The well-known quadrupole variation method was used to determine the feasibility of measuring the transverse beam emittance. The beam size measured at the beam profile monitor (BPM) is to be utilized and the transformation of beam by transfer matrix is to be applied being taken under various transport condition of varying quadrupole magnetic strength. Two different methods where beam optics are based on the linear matrix formalism and particle tracking with a 3-D magnetic field distribution obtained by using OPERA3D TOSCA, are applied to transport the beam. The fittings for the transformation parameters are used to estimate the transverse emittance and the twiss parameters at the entrance of the quadrupole in the ESS. Including several systematic studies, we conclude that within the uncertainty the estimated emittances are consistent with the ones calculated by using Monte Carlo simulations.

An, Dong Hyun; Hahn, Garam; Park, Chawon

2015-02-01

341

Particle dynamics in damped nonlinear quadrupole ion traps  

NASA Astrophysics Data System (ADS)

We examine the motions of particles in quadrupole ion traps as a function of damping and trapping forces, including cases where nonlinear damping or nonlinearities in the electric field geometry play significant roles. In the absence of nonlinearities, particles are either damped to the trap center or ejected, while their addition brings about a rich spectrum of stable closed particle trajectories. In three-dimensional (3D) quadrupole traps, the extended orbits are typically confined to the trap axis, and for this case we present a 1D analysis of the relevant equation of motion. We follow this with an analysis of 2D quadrupole traps that frequently show diamond-shaped closed orbits. For both the 1D and 2D cases, we present experimental observations of the calculated trajectories in microparticle ion traps. We also report the discovery of a new collective behavior in damped 2D microparticle ion traps, where particles spontaneously assemble into a remarkable knot of overlapping, corotating diamond orbits, self-stabilized by air currents arising from the particle motion.

Vinitsky, Eugene A.; Black, Eric D.; Libbrecht, Kenneth G.

2015-04-01

342

Position Stability Monitoring of THEthe LCLS Undulator Quadrupoles  

SciTech Connect

X-ray FELs demand that the positions of undulator components be stable to less than 1 {mu}m per day. Simultaneously, the undulator length increases significantly in order to saturate at x-ray wavelengths. To minimize the impact of the outside environment, the Linac Coherent Light Source (LCLS) undulator is placed underground, but reliable data about ground motion inside such a tunnel was not available in the required stability range during the planning phase. Therefore, a new position monitor system had been developed and installed with the LCLS undulator. This system is capable of measuring x, y, roll, pitch and yaw of each of the 33 undulator quadrupoles with respect to stretched wires. Instrument resolution is about 10 nm and instrument drift is negligible. Position data of individual quadrupoles can be correlated along the entire 132-m long undulator. The system has been under continuous operation since 2009. This report describes long term experiences with the running system and the observed positional stability of the undulator quadrupoles.

Nuhn, Heinz Dieter; Gassner, Georg; Peters, Franz; /SLAC

2012-03-26

343

Nuclear pygmy modes and the dynamics of the nuclear skin  

E-print Network

The information on pygmy resonances reveals new aspects on the isospin dynamics of the nucleus with important astrophysical consequences. In this connection, the precise knowledge of nuclear response functions plays a key role in the determination of photonuclear reactions cross sections which are of importance for the synthesis of heavy neutron-rich elements. For that purpose, a theoretical method based on density functional theory and multi-phonon approach is applied for investigations of nuclear excitations with different multipolarities and energies in stable and exotic nuclei. The possible relation of low-energy modes to the properties of neutron or proton skins is systematically investigated for isotonic and isotopic chains. Our studies of dipole and quadrupole response functions and the corresponding transition densities indicate new pygmy dipole and pygmy quadrupole resonances, describing oscillations of the nuclear skin. Also, the presence of skins is found to affect the magnetic response of nuclei.

Nadia Tsoneva; Horst Lenske

2012-11-05

344

Nuclear Quadrupole Resonance Studies of the Sorc Sequence and Nuclear Magnetic Resonance Studies of Polymers.  

NASA Astrophysics Data System (ADS)

The behavior of induction signals during steady -state pulse irradiation in ^{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 ^{15}N was studied at four different temperatures between 27^ circ and 120^circ Celsius and the correlation times for polymer backbone motions were obtained. Nafion films containing, water (D_2 O and H_2^{17}O) and methanol (CH_3OD, CH _3^{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 ^2H NMR lineshapes. Activation energies extracted from ^2H spin-lattice relaxation data on the high temperature side of the T_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 anisotropy of the host polymer. Activation volumes corresponding to a specific dynamical process were obtained from measurements of spin-lattice relaxation vs. pressure. From the NMR measurements of Nafion films containing methanol, it was found that the molecular motion is much more rapid than the molecular motion of water in Nafion membranes.

Jayakody, Jayakody R. Pemadasa

1993-01-01

345

Mechanism of nuclear dissipation in fission and heavy-ion reactions  

SciTech Connect

Recent advances in the theoretical understanding of nuclear dissipation at intermediate excitation energies are reviewed, with particular emphasis on a new surface-plus-window mechanism that involves interactions of either one or two nucleons with the moving nuclear surface and also, for dumbbell-like shapes encountered in fission and heavy-ion reactions, the transfer of nucleons through the window separating the two portions of the system. This novel dissipation mechanism provides a unified macroscopic description of such diverse phenomena as widths of isoscalar giant quadrupole and giant octupole resonances, mean fission-fragment kinetic energies and excitation energies, dynamical thresholds for compound-nucleus formation, enhancement in neutron emission prior to fission, and widths of mass and charge distributions in deep-inelastic heavy-ion reactions. 41 refs., 8 figs.

Nix, J.R.; Sierk, A.J.

1986-01-01

346

Understanding long-term corrosion of Alloy 22 container in the potential Yucca Mountain repository for high-level nuclear waste disposal  

NASA Astrophysics Data System (ADS)

Alloy 22 (Ni-22Cr-13Mo-3W-4Fe) is the candidate material for the waste package outer container in a potential geologic repository for high-level nuclear waste disposal at Yucca Mountain, Nevada. This alloy exhibits very low corrosion rates in the absence of environmental conditions promoting crevice corrosion. However, there are uncertainties regarding Alloy 22's corrosion performance when general corrosion rates and susceptibility to crevice corrosion are extrapolated to a geological time period (e.g. 10 5 years). This paper presents an analysis of available literature information relevant to the long-term extrapolation of general corrosion processes and the crevice corrosion behavior of Alloy 22, under potential repository environments. For assessment of general corrosion rates, potential degradation processes causing the loss of the long-term persistence of passive film formed are considered. For crevice corrosion, induction time, and the extent of susceptibility and opening area, are considered. Disclaimer: The US Nuclear Regulatory Commission (NRC) staff views expressed herein are preliminary and do not constitute a final judgment or determination of the matters addressed nor of the acceptability of a license application for a geologic repository at Yucca Mountain. The paper describes work performed by the Center for Nuclear Waste Regulatory Analyses (CNWRA) for NRC under Contract Number NRC-02-02-012. The activities reported here were performed by CNWRA on behalf of the NRC office of Nuclear Material Safety and Safeguards, Division of High Level Waste Repository Safety. This paper is an independent product of the CNWRA and does not necessarily reflect the view or regulatory position of the NRC.

Ahn, T.; Jung, H.; He, X.; Pensado, O.

2008-09-01

347

Understanding Instructions.  

ERIC Educational Resources Information Center

This guide is intended to help adult basic education (ABE) teachers teach their students to understand instructions in their daily lives. The 25 learning activities included all develop students' skills in the area of following directions by using basic situations drawn from everyday life. The following activities are included: sequencing pictures…

Milburn, Val

348

Understanding Federalism.  

ERIC Educational Resources Information Center

Urges returning to the original federalist debates to understand contemporary federalism. Reviews "The Federalist Papers," how federalism has evolved, and the centralization of the national government through acts of Congress and Supreme Court decisions. Recommends teaching about federalism as part of teaching about U.S. government today. (NL)

Hickok, Eugene W., Jr.

1990-01-01

349

Understanding Exploration  

NSDL National Science Digital Library

This classroom activity, which is structured as a series of mini-research projects, helps students understand how technological advances have aided the exploration of Antarctica. The printable handout includes a set of 10 research topics in three categories, explorers, Antarctica today, and technological advances for you to assign to small student teams.

350

Bose-Einstein Condensation in an electro-pneumatically transformed quadrupole-Ioffe magnetic trap  

E-print Network

We report a novel approach for preparing a Bose-Einstein condensate (BEC) of $^{87}$Rb atoms using electro-pneumatically driven transfer of atoms into a Quadrupole-Ioffe magnetic trap (QUIC Trap). More than 5$\\times$$10^{8}$ atoms from a Magneto-optical trap are loaded into a spherical quadrupole trap and then these atoms are transferred into an Ioffe trap by moving the Ioffe coil towards the center of the quadrupole coil, thereby, changing the distance between quadrupole trap center and the Ioffe coil. The transfer efficiency is more than 80 \\%. This approach is different from a conventional approach of loading the atoms into a QUIC trap wherein the spherical quadrupole trap is transformed into a QUIC trap by changing the currents in the quadrupole and the Ioffe coils. The phase space density is then increased by forced rf evaporative cooling to achieve the Bose-Einstein condensation having more than $10^{5}$ atoms.

Sunil Kumar; Sumit Sarkar; Gunjan Verma; Chetan Vishwakarma; Md. Noaman; Umakant Rapol

2014-08-20

351

Bose-Einstein condensation in an electro-pneumatically transformed quadrupole-Ioffe magnetic trap  

NASA Astrophysics Data System (ADS)

We report a novel approach for preparing a Bose–Einstein condensate (BEC) of 87Rb atoms using an electro-pneumatically driven transfer of atoms into a quadrupole-Ioffe magnetic trap (QUIC trap). More than 5 × {{10}8} atoms from a magneto-optical trap are loaded into a spherical quadrupole trap and then transferred into an Ioffe trap by moving the Ioffe coil towards the center of the quadrupole coil thereby changing the distance between the quadrupole trap center and the Ioffe coil. The transfer efficiency is more than 80%. This approach is different from the conventional approach of loading the atoms into a QUIC trap wherein the spherical quadrupole trap is transformed into a QUIC trap by changing the currents in the quadrupole and the Ioffe coils. The phase space density is then increased by forced rf evaporative cooling to achieve Bose–Einstein condensation of more than 105 atoms.

Kumar, Sunil; Sarkar, Sumit; Verma, Gunjan; Vishwakarma, Chetan; Noaman, Md; Rapol, Umakant

2015-02-01

352

Testing of Nb3Sn quadrupole coils using magnetic mirror structure  

SciTech Connect

This paper describes the design and parameters of a quadrupole mirror structure for testing the mechanical, thermal and quench performance of single shell-type superconducting quadrupole coils at field, current and force levels similar to that of real magnet. The concept was experimentally verified by testing two quadrupole coils, previously used in quadrupole models, in the developed mirror structure in the temperature range from 4.5 to 1.9 K. The coils were instrumented with voltage taps, heaters, and strain gauges to monitor their mechanical and thermal properties and quench performance. A new quadrupole coil made of improved Nb{sub 3}Sn RRP-108/127 strand and cable insulation based on E-glass tape was also tested using this structure. The fabrication and test results of the quadrupole mirror models are reported and discussed.

Zlobin, A.V.; Andreev, N.; Barzi, E.; Bossert, R.; Chlachidze, G.; Kashikhin, V.S.; Kashikhin, V.V.; Lamm, M.; Novitski, I.; Tartaglia, M.; Tompkins, J.C.; /Fermilab

2009-07-01

353

Design and construction of a radiation resistant quadrupole using metal oxide insulated CICC  

SciTech Connect

The construction of a engineering test model of a radiation resistant quadrupole is described. The cold-iron quadrupole uses coils fabricated from metal-oixide (synthetic spinel) insulated Cable-In-Conduit-Conductor (CICC). The superconductor is NbTi in a copper matrix. The quadrupole is designed to produce a pole-tip field of 2 T with an operating current of 7,000 A.

Albert F. Zeller

2012-12-28

354

Performance of Series-Design Prototype Main Quadrupoles for the LHC  

Microsoft Academic Search

After the successful construction of two first-generation prototypes of the main quadrupoles for the LHC, three series-design prototypes have been further manufactured at CEA-Saclay. Together with the sextupole-dipole corrector magnets and tuning quadrupoles, these twin-aperture main quadrupoles are assembled into the cold masses of the so-called short straight sections. Already during their fabrication, the collared coils and later the completed

J Billan; L Bottura; M Peyrot; Vittorio Remondino; J M Rifflet; A Siemko; F Simon; Theodor Tortschanoff

2000-01-01

355

Development and Coil Fabrication for the LARP 3.7-m Long Nb3Sn Quadrupole  

Microsoft Academic Search

The U.S. LHC Accelerator Research Program (LARP) has started the fabrication of 3.7-m long Nb3Sn quadrupole models. The Long Quadrupoles (LQ) are ldquoProof-of-Principlerdquo magnets which are to demonstrate that Nb3Sn technology is mature for use in high energy particle accelerators. Their design is based on the LARP Technological Quadrupole (TQ) models, developed at FNAL and LBNL, which have design gradients

Giorgio Ambrosio; Nikolai Andreev; Michael Anerella; Emanuela Barzi; Rodger Bossert; Shlomo Caspi; Guram Chlachidize; Daniel R. Dietderich; Helene Felice; Paolo Ferracin; Arup Ghosh; R. Hafalia; R. Hannaford; G. Jochen; V. V. Kashikhin; P. Kovach; Michael Lamm; A. Lietzke; Al D. McInturff; Joseph F. Muratore; F. Nobrega; I. Novitsky; S. Peggs; Soren Prestemon; Gianluca Sabbi; Jesse Schmalzle; Daniele Turrioni; Peter Wanderer; G. Whitson; Alexander V. Zlobin

2009-01-01

356

Stability of the coherent quadrupole oscillations excited by the beam-beam interaction  

SciTech Connect

We study the coherent quadrupole motion in the presence of beam-beam interaction, using a linear approximation to the beam-beam force. The corresponding beam-beam limit is determined by evaluating the eigenvalues of a system of linear equations describing the coherent quadrupole motion. We find that the stability of the quadrupole motions imposes severe limits on the beam current, as is the case for the dipole instability. Preliminary results of this study have appeared elsewhere.

Kamiya, Y.; Chao, A.W.

1983-10-01

357

Development and Coil Fabrication for the LARP 3.7-m Long Nb3Sn Quadrupole  

Microsoft Academic Search

The U.S. LHC Accelerator Research Program (LARP) has started the fabrication of 3.7-m long NbSn quadrupole models. The Long Quadrupoles (LQ) are 'Proof-of-Principle' magnets which are to demonstrate that NbSn technology is mature for use in high energy particle accelerators. Their design is based on the LARP Technological Quadrupole (TQ) models, developed at FNAL and LBNL, which have design gradients

G. Ambrosio; N. Andreev; M. Anerella; E. Barzi; R. Bossert; S. Caspi; G. Chlachidize; D. Dietderich; H. Felice; P. Ferracin; A. Ghosh; R. Hafalia; R. Hannaford; G. Jochen; V. V. Kashikhin; P. Kovach; M. Lamm; A. Lietzke; A. McInturff; Muratore; F. Nobreaga; I. Novitsky; S. Peggs; S. Prestemon; G. L. Sabbi; J. Schmalzle; D. Turrioni; P. Wanderer; G. Whitson; A. V. Zlobin

2008-01-01

358

Understanding Boston  

NSDL National Science Digital Library

How does one begin to understand the workings of a major metropolis? It can be a tough job even for a seasoned expert in urbanology or governance. The Boston Foundation has offered up this area of its website to bring together resources that address the thorniest issues facing the Hub, including public schools, public health, transportation, and housing costs. First up is the Research, Reports, and Forums area, which includes working papers on public health throughout the region, links to the Greater Boston Indicator database, and information about changing models of urban governance throughout the region. The site also includes a group of areas dedicated to Understanding Boston that include Civic Engagement, Community Safety, and Cultural Vitality. Within each of these areas, visitors can look over working papers, read about upcoming events and conferences, and learn about the Foundation's long range plans.

359

Understanding dressings.  

PubMed

Currently our understanding of chronic wound pathophysiology is deficient in knowing what specifically is lacking during arrested wound healing. Autologous or allogenic keratinocytes have been used successfully to treat chronic wounds, as have composites containing diverse substances such as allogenic dermis, polyglycolic acid, or collagen mesh combined with keratinocytes or fibroblasts (Table 6). In spite of great technological advances and increased understanding, there is much work to be done. We look forward to the day when our knowledge of wound healing has progressed to the point when specific deficiencies can be supplemented by dressing contents, and when "smart" dressings can adapt to the changing wound as it progresses through the phases of healing. PMID:9696903

Ladin, D A

1998-07-01

360

Understanding Flight  

SciTech Connect

Through the years the explanation of flight has become mired in misconceptions that have become dogma. Wolfgang Langewiesche, the author of 'Stick and Rudder' (1944) got it right when he wrote: 'Forget Bernoulli's Theorem'. A wing develops lift by diverting (from above) a lot of air. This is the same way that a propeller produces thrust and a helicopter produces lift. Newton's three laws and a phenomenon called the Coanda effect explain most of it. With an understanding of the real physics of flight, many things become clear. Inverted flight, symmetric wings, and the flight of insects are obvious. It is easy to understand the power curve, high-speed stalls, and the effect of load and altitude on the power requirements for lift. The contribution of wing aspect ratio on the efficiency of a wing, and the true explanation of ground effect will also be discussed.

Anderson, David

2001-01-31

361

Understanding Science  

NSDL National Science Digital Library

The mission of the Understanding Science website is "to provide a fun, accessible, and free resource that accurately communicates what science is and how it really works." The project has a specific focus on assisting teachers in keeping young people interested in science; to support this goal, the site includes a range of materials for teachers. Visitors can start with the Site Tour area to learn about the structure and organization of the site. Moving along, the Understanding Science 101 area includes quick reviews of topics like How Science Works, What is Science?, and Why Science Matters. The Resource Library contains classroom activities, teaching tools, and strategies for keeping students thinking and engaged. Visitors can also use the Correcting Misconceptions area to address certain commonly held beliefs like Science is complete or Science is a collection of facts. Finally, visitors can sign up to receive updates when the site adds new information.

2012-08-17

362

Understanding Youth  

E-print Network

activities that develop skill coordination and enhance the individual?s understanding and appreciation of a growing and changing body. Avoid physical activities that emphasize awkwardness. ? Design health and grooming activities that help youth develop... and maturity levels. ? Design activities that strengthen male and female roles. ? Focus some activities on the physical self to help youth accept who they are. Mental development ? Allow youth to set their own goals, make their own plans, implement those...

Howard, Jeff W.

2005-05-10

363

UNDERSTANDING THE \\  

Microsoft Academic Search

Intercultural learning is often assumed to be an automatic benefit of e-mail exchanges between groups of learners in different countries, but little research exists on whether on-line intercultural collaboration does actually develop learners' understanding of the other culture's perspective and world view. This paper reviews what recent literature suggests intercultural learning to involve and then reports on a year-long e-mail

Robert O'Dowd

2003-01-01

364

Understanding Drought  

NSDL National Science Digital Library

Understanding Drought--This webcast provides an introduction to drought. It presents the measures and scales of drought and how drought is monitored. It also covers how drought is predicted, the impacts of drought, and provides information about drought-related resources. This content serves as a foundation to learning more about climate variability and operational climate services and prepares users for the national implementation of NIDIS. This module was last updated on Sept 28, 2009.

COMET

2009-02-11

365

Nuclear astrophysics  

SciTech Connect

The problem of core-collapse supernovae is used to illustrate the many connections between nuclear astrophysics and the problems nuclear physicists study in terrestrial laboratories. Efforts to better understand the collapse and mantle ejection are also motivated by a variety of interdisciplinary issues in nuclear, particle, and astrophysics, including galactic chemical evolution, neutrino masses and mixing, and stellar cooling by the emission of new particles. The current status of theory and observations is summarized.

Haxton, W.C.

1992-01-01

366

Nuclear astrophysics  

SciTech Connect

The problem of core-collapse supernovae is used to illustrate the many connections between nuclear astrophysics and the problems nuclear physicists study in terrestrial laboratories. Efforts to better understand the collapse and mantle ejection are also motivated by a variety of interdisciplinary issues in nuclear, particle, and astrophysics, including galactic chemical evolution, neutrino masses and mixing, and stellar cooling by the emission of new particles. The current status of theory and observations is summarized.

Haxton, W.C.

1992-12-31

367

Testing Understanding and Understanding Testing.  

ERIC Educational Resources Information Center

Provides examples in which graphs are used in the statements of problems or in their solutions as a means of testing understanding of mathematical concepts. Examples (appropriate for a beginning course in calculus and analytic geometry) include slopes of lines and curves, quadratic formula, properties of the definite integral, and others. (JN)

Pedersen, Jean; Ross, Peter

1985-01-01

368

Understanding: "Knowledge", "Belief", and "Understanding"  

ERIC Educational Resources Information Center

The following paper is intended as an exercise in "friendly criticism" of one of Harvey Siegel's and Mike Smith's ("Knowing, Believing and Understanding", this volume). I'm in substantial sympathy with the general thrust of their paper and my remarks merely provide some criticism of their discussion's conceptual coherence and clarity and a…

Davson-Galle, Peter

2004-01-01

369

Geometry and properties of the plasma in a quadrupole ion pump  

NASA Technical Reports Server (NTRS)

The diameter of the plasma in a quadrupole ionization gauge and quadrupole ion pump has been measured as a function of pressure. The radio-frequency quadrupole systems are tuned in such a way that electrons remain on stable trajectories in the center of the tube. Being emitted at one end, the electrons encounter an inverted field at the other end so that they travel on spiral paths back and forth until they collide with the rest gas molecules, producing ions which are collected as an ion current at a cylinder surrounding the four hyperbolically shaped quadrupole electrodes.

Schwarz, H.

1977-01-01

370

The Erez-Rosen metric and the role of the quadrupole on light propagation  

E-print Network

The gravitational field of a static body with quadrupole moment is described by an exact solution found by Erez and Rosen. Here we investigate the role of the quadrupole in the motion, deflection and lensing of a light ray in the above metric. The standard lensing observables like image positions and magnification have been explicitly obtained in the weak field and small quadrupole limit. In this limit the spacetime metric appears as the natural generalization to quadrupole corrections of the metric form adopted also in current astrometric models. Hence, the corresponding analytical solution of the inverse ray tracing problem as well as the consistency with other approaches are also discussed.

Donato Bini; Mariateresa Crosta; Fernando de Felice; Andrea Geralico; Alberto Vecchiato

2014-08-22

371

Performance Characteristics of a MEMS Quadrupole Mass Filter With Square Electrodes: Experimental and Simulated Results  

E-print Network

Size reduction in quadrupole mass spectrometers (QMSs) is an ongoing requirement driven by the needs of space exploration, portable, and covert monitoring applications. Microelectromechanical systems (MEMS) technology ...

Hogan, Thomas J.

372

Time resolved laser-induced fluorescence of electrosprayed ions confined in a linear quadrupole trap  

SciTech Connect

We have designed and constructed a linear quadrupole ion trap for the measurement of laser-induced fluorescence (LIF) of mass selected gas-phase ions produced by electrospray ionization. The instrument consists of a simple electrospray source, radiofrequency octopole guide, a dc quadrupole bender, a quadrupole mass filter, the linear quadrupole trap (which is equipped with optics for LIF collection and a channeltron ion detector), and several multielement focusing lenses. With this instrument, the LIF decay lifetime of gas-phase Rhodamine 640 radical cations is determined for the first time.

Friedrich, Jochen; Fu Jinmei; Hendrickson, Christopher L.; Marshall, Alan G.; Wang Yisheng [Ion Cyclotron Resonance Program, National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310-4005 (United States); Institute of Atomic and Molecular Sciences, Academia Sinica, P. O. Box 23-166, Taipei, Taiwan (China)

2004-11-01

373

Progress in the Development of Superconducting Quadrupoles forHeavy-ion Fusion  

SciTech Connect

The Heavy Ion Fusion program is developing single aperture superconducting quadrupoles based on NbTi conductor, for use in the High Current Experiment at Lawrence Berkeley National Laboratory. Following the fabrication and testing of prototypes using two different approaches, a baseline design has been selected and further optimized. A prototype cryostat for a quadrupole doublet, with features to accommodate induction acceleration modules, is being fabricated. The single aperture magnet was derived from a conceptual design of a quadrupole array magnet for multi-beam transport. Progress on the development of superconducting quadrupole arrays for future experiments is also reported.

Faltens, A.; Lietzke, A.; Sabbi, G.; Seidl, P.; Lund, S.; Manahan, R.; Martovetsky, N.; Gung, C.; Minervini, J.; Schultz, J.; Myatt, L.; Meinke, R.

2002-08-19

374

Progress in the development of superconducting quadrupoles for heavy ion fusion  

SciTech Connect

The Heavy Ion Fusion program is developing single aperture superconducting quadrupoles based on NbTi conductor, for use in the High Current Experiment at Lawrence Berkeley National Laboratory. Following the fabrication and testing of prototypes using two different approaches, a baseline design has been selected and further optimized. A prototype cryostat for a quadrupole doublet, with features to accommodate induction acceleration modules, is being fabricated. The single aperture magnet was derived from a conceptual design of a quadrupole array magnet for multi-beam transport. Progress on the development of superconducting quadrupole arrays for future experiments is also reported.

Faltens, A.; Lietzke, A.; Sabbi, G.; Seidl, P.; Lund, S.; Manahan, B.; Martovetsky, N.; Gung, C.; Minervini, J.; Schultz, J.; Myatt, L.; Meinke, R.

2002-05-24

375

Comparison of conventional and novel quadrupole drift tube magnets inspired by Klaus Halbach  

SciTech Connect

Quadrupole drift tube magnets for a heavy-ion linac provide a demanding application of magnet technology. A comparison is made of three different solutions to the problem of providing an adjustable high-field-strength quadrupole magnet in a small volume. A conventional tape-wound electromagnet quadrupole magnet (conventional) is compared with an adjustable permanent-magnet/iron quadrupole magnet (hybrid) and a laced permanent-magnet/iron/electromagnet (laced). Data is presented from magnets constructed for the SuperHILAC heavy-ion linear accelerator, and conclusions are drawn for various applications.

Feinberg, B. [Lawrence Berkeley Lab., CA (United States)

1995-02-01

376

Design, development, and acceleration trials of radio-frequency quadrupole  

SciTech Connect

A deuteron radio frequency quadrupole (RFQ) accelerator has been designed, fabricated, and tested at BARC, which will be used for neutron generation. The RFQ operates at a frequency of 350 MHz and needs an inter-vane voltage of 44 kV to accelerate the deuteron beam to 400 keV within a length of 1.03 m. The error analysis shows that the offset of two opposite vanes in the same direction by 100 ?m leads to a change in resonant frequency by 1.3 MHz and a significant change of fields in the quadrants (?±40% with respect to average field). From the 3D analysis, we have observed that the unwanted dipole mode frequencies are very near to the quadrupole mode frequency which will make structure sensitive to the perturbations. In order to move the dipole modes away from the quadrupole modes, we have used the dipole stabilizer rods. The 5 wire transmission line theory was used to study the perturbative analysis of the RFQ and based on this a computer program has been written to tune the cavity to get required field distribution. Based on these studies, a 1.03 m long RFQ made of OFE copper has been fabricated and tested. Even though the RFQ was designed for deuteron (D{sup +}) beam, we tested it by accelerating both the proton (H{sup +}) and D{sup +} beams. The RFQ was operated in pulsed mode and accelerated both H{sup +} and D{sup +} beams to designed values of 200 and 400 keV, respectively. The measured parameters are in good agreement with the designed values validating our simulations and fabrication processes. In this paper, simulations, RF measurements, and beam commissioning results are presented.

Rao, S. V. L. S., E-mail: svlsrao@gmail.com; Jain, Piyush; Pande, Rajni; Roy, Shweta; Mathew, Jose V.; Kumar, Rajesh; Pande, Manjiri; Krishnagopal, S.; Gupta, S. K.; Singh, P. [Ion Accelerator Development Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)] [Ion Accelerator Development Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

2014-04-15

377

Radio frequency quadrupole for Landau damping in accelerators  

NASA Astrophysics Data System (ADS)

We propose using a radio frequency quadrupole (RFQ) to introduce both the longitudinal spread of betatron frequency and the transverse spread of synchrotron frequency for Landau damping of transverse beam instabilities in accelerators. The existing theory of stability diagrams for Landau damping is applied to the case of a RFQ. As an example, the required quadrupolar strength is calculated for stabilizing the Large Hadron Collider beams at 7 TeV. It is shown that this strength can be provided by a superconducting rf device only a few meters long.

Grudiev, A.

2014-01-01

378

Electrostatic quadrupole accelerator for the heavy ion fusion project  

SciTech Connect

A full scale (2 MeV, 800 mA, K{sup +}), low emittance injector for the Heavy Ion Fusion Project has been built at LBL. It consists of a 700 keV diode pre-injector followed by an electrostatic quadrupole accelerator (ESQ) which provides strong focusing for the space-charge dominated beam and simultaneously accelerates the ions to 2 MeV. The actual operation of this new machine has exceeded design parameters. Design of the accelerator, report on experiments performed in connection with the evaluation and characterization of the ESQ and corresponding 3D Particle in Cell simulations will be presented.

Henestroza, E.; Yu, S.; Eylong, S. [Lawrence Berkeley Lab., CA (United States)

1994-12-31

379

Miniature quadrupole mass spectrometer having a cold cathode ionization source  

DOEpatents

An improved quadrupole mass spectrometer is described. The improvement lies in the substitution of the conventional hot filament electron source with a cold cathode field emitter array which in turn allows operating a small QMS at much high internal pressures then are currently achievable. By eliminating of the hot filament such problems as thermally "cracking" delicate analyte molecules, outgassing a "hot" filament, high power requirements, filament contamination by outgas species, and spurious em fields are avoid all together. In addition, the ability of produce FEAs using well-known and well developed photolithographic techniques, permits building a QMS having multiple redundancies of the ionization source at very low additional cost.

Felter, Thomas E. (Livermore, CA)

2002-01-01

380

Quench observation using quench antennas on RHIC IR quadrupole magnets  

SciTech Connect

Quench observation using quench antennas is now being performed routinely on RHIC dipole and quadrupole magnets. Recently, a quench antenna was used on a RHIC IR magnet which is heavily instrumented with voltage taps. It was confirmed that the signals detected in the antenna coils do not contradict the voltage tap signals. The antenna also detects a sign of mechanical disturbance which could be related to a training quench. This paper summarizes signals detected in the antenna and discusses possible causes of these signals.

Ogitsu, T.; Terashima, A.; Tsuchiya, K. [KEK, National Laboratory for High Energy Physics, Tsukuba, Ibaraki (Japan); Ganetis, G.; Muratore, J.; Wanderer, P. [Brookhaven National Lab., Upton, NY (United States)

1995-07-01

381

Quench margin measurement in Nb3Sn quadrupole magnet  

SciTech Connect

One of the possible practical applications of the Nb{sub 3}Sn accelerator magnets is the LHC luminosity upgrade that involves replacing the present NbTi focusing quadrupoles in two high-luminosity interaction regions (IR). The IR magnets are exposed to strong radiation from the interaction point that requires a detailed investigation of the magnet operating margins under the expected radiation-induced heat depositions. This paper presents the results of simulation and measurement of quench limits and temperature margins for a Nb{sub 3}Sn model magnet using a special midplane strip heater.

Kashikhin, V.V.; Bossert, R.; Chlachidze, G.; Lamm, M.; Novitski, I.; Zlobin, A.V.; /Fermilab

2008-08-01

382

Status of the quadrupoles for RHIC (Relativistic Heavy Ion Collider)  

SciTech Connect

The proposed Relativistic Heavy Ion Collider (RHIC) will require 408 regular arc quadrupoles. Two full size prototypes have been constructed and tested. The construction uses the single layer, collarless concept which has been successful in the RHIC dipoles. Both the magnets attained short sample current, which is 60% higher than the operating current. This corresponds to a gradient of 113 T/m with clear bore of 80 mm. The preliminary field measurements are in agreement with the calculations, with the exception of an unexpectedly large show sextupole. 2 refs., 5 figs., 1 tab.

Thompson, P.A.; Cottingham, J.G.; Garber, M.; Ghosh, A.; Goodzeit, C.; Greene, A.; Herrera, J.; Kahn, S.; Kelly, E.; Morgan, G.

1989-01-01

383

Small Aperture BPM to Quadrupole Assembly Tolerance Study  

SciTech Connect

The LCLS injector and linac systems utilize a series of quadrupole magnets with a beam position monitor (BPM) captured in the magnet pole tips. The BPM measures the electron beam position by comparing the electrical signal from 4 electrodes and interpolating beam position from these signals. The manufacturing tolerances of the magnet and BPM are critical in determining the mechanical precision of the electrodes relative to the nominal electron beam Z-axis. This study evaluates the statistical uncertainty of the electrodes center axis relative to the nominal electron beam axis.

Fong, K. W.

2010-12-07

384

Optimized Superconducting Quadrupole Arrays for Multiple Beam Transport  

SciTech Connect

This research project advanced the development of reliable, cost-effective arrays of superconducting quadrupole magnets for use in multi-beam inertial fusion accelerators. The field in each array cell must be identical and meet stringent requirements for field quality and strength. An optimized compact array design using flat double-layer pancake coils was developed. Analytical studies of edge termination methods showed that it is feasible to meet the requirements for field uniformity in all cells and elimination of stray external field in several ways: active methods that involve placement of field compensating coils on the periphery of the array or a passive method that involves use of iron shielding.

Meinke, Rainer, B.; Goodzeit, Carl, L.; Ball, Millicent, J.

2005-09-20

385

Understanding Evolution  

NSDL National Science Digital Library

The intent of this website is to give teachers a background understanding of evolution, opening the door by giving them strategies for teaching and responding to misconceptions and roadblocks. The heart of the site is Evolution 101, which can serve as a primer to evolutionary theory or an intensive course in the nitty gritty details of speciation, micro- and macroevolution, and ongoing research into how evolution happens. The site is replete with practical examples of how evolution impacts our daily lives, including lesson plans about bunny breeding, the problem of antibiotic resistance in disease organisms, and the conservation and breeding of endangered species.

386

Understanding energy 1 Understanding Energy  

E-print Network

Traditional physics texts develop ideas and concepts in a hierarchical structure. Authors assume that the proper way to understand the subject is by working your way up through a web of ideas, from simple stuff at the bottom to higher concepts at the top. A serious defect in that approach to writing school-level physics is that by keeping it simple at the basic level we can also make it

Ian M. Sefton

387

Understanding ayurveda.  

PubMed

Ayurveda needs to achieve its full potential both in India and globally. This requires imparting to its students full appreciation of Ayurveda's power and strength, particularly proper understanding of the advantages of applying it to treat chronic and acute diseases. To this end, we explain the necessity of learning Sanskrit as a medium of study, and the advantages of learning the Texts in the traditional way, rather than relying on translations with all the loss of meaning and precision, which that entails. We emphasize the use of Triskandhakosha as a means to fully understand Ayurveda fundamental concepts and technical terms, so that all their shades of meaning are fully understood, and all their usages given in different places in the texts. Only by such methods can full appreciation of Ayurvedic wisdom be achieved, and the full depth and power of its knowledge be applied. Only then will its true status among systems of medicine come to be appreciated, either in India or more widely in the world as a whole. PMID:21829307

Gadgil, Vaidya Dilip

2010-01-01

388

Understanding ageing.  

PubMed Central

A broad biological approach makes it possible to understand why ageing exists and also why different mammalian species have very different maximum longevities. The adult organism is maintained in a functional state by at least ten major mechanisms, which together comprise a substantial proportion of all biological processes. These maintenance mechanisms eventually fail, because the evolved physiological and anatomical design of higher animals is incompatible with continual survival. The lifespan of each mammalian species depends on the efficiency of maintenance of their cells, tissues and organisms, and there is much evidence that such maintenance is more effective in long-lived species, such as man, than in short-lived small mammals. It is also evident that there is an inverse relationship between reproductive potential and longevity, which would be expected if total metabolic resources are shared between investment in reproduction, and investment in the preservation of the adult body. It is proposed that the eventual failure of maintenance leads to the pathological changes seen in age-associated disease. Although we now have a biological understanding of the ageing process, much future research will be needed to uncover the cellular and molecular changes which give rise to age-associated diseases. The major aim of such research is to devise procedures to delay or prevent the onset of these diseases. PMID:9460062

Holliday, R

1997-01-01

389

Understanding resilience  

PubMed Central

Resilience is the ability to adapt successfully in the face of stress and adversity. Stressful life events, trauma, and chronic adversity can have a substantial impact on brain function and structure, and can result in the development of posttraumatic stress disorder (PTSD), depression and other psychiatric disorders. However, most individuals do not develop such illnesses after experiencing stressful life events, and are thus thought to be resilient. Resilience as successful adaptation relies on effective responses to environmental challenges and ultimate resistance to the deleterious effects of stress, therefore a greater understanding of the factors that promote such effects is of great relevance. This review focuses on recent findings regarding genetic, epigenetic, developmental, psychosocial, and neurochemical factors that are considered essential contributors to the development of resilience. Neural circuits and pathways involved in mediating resilience are also discussed. The growing understanding of resilience factors will hopefully lead to the development of new pharmacological and psychological interventions for enhancing resilience and mitigating the untoward consequences. PMID:23422934

Wu, Gang; Feder, Adriana; Cohen, Hagit; Kim, Joanna J.; Calderon, Solara; Charney, Dennis S.; Mathé, Aleksander A.

2013-01-01

390

Extracting the Omega- electric quadrupole moment from lattice QCD data  

SciTech Connect

The Omega- has an extremely long lifetime, and is the most stable of the baryons with spin 3/2. Therefore the Omega- magnetic moment is very accurately known. Nevertheless, its electric quadrupole moment was never measured, although estimates exist in different formalisms. In principle, lattice QCD simulations provide at present the most appropriate way to estimate the Omega- form factors, as function of the square of the transferred four-momentum, Q2, since it describes baryon systems at the physical mass for the strange quark. However, lattice QCD form factors, and in particular GE2, are determined at finite Q2 only, and the extraction of the electric quadrupole moment, Q_Omega= GE2(0) e/(2 M_Omega), involves an extrapolation of the numerical lattice results. In this work we reproduce the lattice QCD data with a covariant spectator quark model for Omega- which includes a mixture of S and two D states for the relative quark-diquark motion. Once the model is calibrated, it is used to determine Q_Omega. Our prediction is Q_Omega= (0.96 +/- 0.02)*10^(-2) efm2 [GE2(0)=0.680 +/- 0.012].

G. Ramalho, M.T. Pena

2011-03-01

391

Heavy ion plasma confinement in an RF quadrupole trap  

NASA Technical Reports Server (NTRS)

The confinement of an electron free plasma in a pure quadrupole RF electric trap was considered. The ultimate goal was to produce a large density of mercury ions, in order to realize a trapped ion frequency standard using the hyperfine resonance of 199 Hg(+) at 40.7 GHz. An attempt was made to obtain an iodine plasma consisting of equal numbers of positive and negative ions of atomic iodine, the positive iodine ions, being susceptible to charge-exchange with mercury atoms, will produce the desired mercury ions. The experiment showed that the photoproduction of ions pairs in iodine using the necessary UV radiation occurs with a small cross-section, making it difficult to demonstrate the feasibility of space charge neutralization in a quadrupole trap. For this reason it was considered expedient to choose thallium iodide, which has a more favorable absorption spectrum (in the region of 2000 to 2100 A). The results indicate that, although the ionic recombination is a serious limiting factor, a considerable improvement can be obtained in practice for the density of trapped ions, with a considerable advantage in lifetimes for spectroscopic purposes. The ion pair formation by photoionization is briefly reviewed.

Schermann, J.; Major, F. G.

1971-01-01

392

Quadrupole Approximation for Para-Positronium in Relativistic Schrödinger Theory  

E-print Network

The non-relativistic energy levels of para-positronium are calculated in the quadrupole approximation of the interaction potential. This approximation technique takes into account the anisotropy of the electrostatic electron-positron interaction in the lowest order. The states due to different values of the quantum number $(l_z)$ of angular momentum are found to be no longer degenerate as is the case in the conventional theory. The physical origin of this elimination of the conventional degeneracy may intuitively be attributed to the state-dependent inertial \\emph{broadening} of the rotating charge clouds; the corresponding \\emph{anisotropic} deformation (in the quadrupole approximation) lowers then the negative electrostatic interaction energy. The result of this influence of anisotropy is that the states with $l_z=0$ adopt smaller binding energy whereas the states with maximal value of $|l_z|$ (for fixed principal quantum number $n$) have the largest binding energy within the angular momentum multiplet $(-|l_{z,\\mathrm{max}}| \\le l_z \\le |l_{z,\\mathrm{max}}|)$. This yields a certain kind of electric fine-structure splitting with the splitted RST levels being placed in a relatively narrow band around the (highly degenerated) conventional levels.

M. Mattes; M. Sorg

2011-09-11

393

A Quadrupole Band-Pass Filter for LANSCE protons  

NASA Astrophysics Data System (ADS)

Neutrons are produced for many purposes at the LANSCE facility by 800 MeV protons into a thick tungsten target. The reactions also yield a continuum of protons, emerging at energies up to about 700 MeV; these protons are currently absorbed to allow neutron experiments. We have designed a quadrupole doublet band-pass filter to focus a narrow range of proton energies onto small samples, for instance the size of electronic circuit elements. Wrong proton energies are spread over a wider area and diluted. One may thus irradiate such small samples with protons from about 50 to 700 MeV by adjuting the quadrupole current. For a typical example with an existing doublet, a one cm diameter sample could receive protons at 470 MeV with 38 MeV FWHM energy resolution at a flux of 1.9x107 protons per second within that energy band, using the 30 degree port of the WNR facility. The flux of protons below 440 MeV or above 530 MeV is reduced by a factor of ten or more. Since the produced range of proton energies is similar to that of protons above the atmosphere, such a band-pass system would be of great use to study proton-induced processes in the components of orbiting systems.

Wender, Stephen; Peterson, R. J.; Morrow, Jonathon

2010-11-01

394

Compressive mass analysis on quadrupole ion trap systems.  

PubMed

Conventionally, quadrupole ion trap mass spectrometers eject ions of different mass-to-charge ratio (m/z) in a sequential fashion by performing a scan of the rf trapping voltage amplitude. Due to the inherent sparsity of most mass spectra, the detector measures no signal for much of the scan time. By exploiting this sparsity property, we propose a new compressive and multiplexed mass analysis approach--multi Resonant Frequency Excitation (mRFE) ejection. This new approach divides the mass spectrum into several mass subranges and detects all the subrange spectra in parallel for increased mass analysis speed. Mathematical estimation of standard mass spectrum is demonstrated while statistical classification on the parallel measurements remains viable because of the sparse nature of the mass spectra. This method can reduce mass analysis time by a factor of 3-6 and increase system duty cycle by 2×. The combination of reduced analysis time and accurate compound classification is demonstrated in a commercial quadrupole ion trap (QIT) system. PMID:24806048

Chen, Evan Xuguang; Gehm, Michael; Danell, Ryan; Wells, Mitch; Glass, Jeffrey T; Brady, David

2014-07-01

395

A Tandem-electrostatic-quadrupole for accelerator-based BNCT  

NASA Astrophysics Data System (ADS)

A project to develop a Tandem-electrostatic-quadrupole (TESQ) accelerator for accelerator-based boron neutron capture therapy (AB-BNCT) is described. A folded Tandem, with 1.25 MV terminal voltage, combined with an electrostatic quadrupole (ESQ) chain is being proposed. The project goal is a machine capable of delivering 30 mA of 2.5 MeV protons to be used in conjunction with a neutron production target based on the 7Li(p, n) 7Be reaction slightly beyond its resonance at 2.25 MeV. This machine is conceptually shown to be capable of accelerating a 30 mA proton beam to 2.5 MeV. These are the specifications needed to produce sufficiently intense and clean epithermal neutron beams, based on the 7Li(p, n) 7Be reaction, to perform BNCT treatment for deep-seated tumors in less than an hour. This electrostatic machine is the technologically simplest and cheapest solution for optimized AB-BNCT.

Kreiner, A. J.; Kwan, J. W.; Burlón, A. A.; Di Paolo, H.; Henestroza, E.; Minsky, D. M.; Valda, A. A.; Debray, M. E.; Somacal, H.

2007-08-01

396

Adjustable permanent quadrupoles for the next linear collider  

SciTech Connect

The proposed Next Linear Collider (NLC) will require over 1400 adjustable quadrupoles between the main linacs' accelerator structures. These 12.7 mm bore quadrupoles will have a range of integrated strength from 0.6 to 138 Tesla, with a maximum gradient of 141 Tesla per meter, an adjustment range of +0 to {minus}20% and effective lengths from 324 mm to 972 mm. The magnetic center must remain stable to within 1 micron during the 20% adjustment. In an effort to reduce costs and increase reliability, several designs using hybrid permanent magnets have been developed. Four different prototypes have been built. All magnets have iron poles and use Samarium Cobalt to provide the magnetic fields. Two use rotating permanent magnetic material to vary the gradient, one uses a sliding shunt to vary the gradient and the fourth uses counter rotating magnets. Preliminary data on gradient strength, temperature stability, and magnetic center position stability are presented. These data are compared to an equivalent electromagnetic prototype.

James T. Volk et al.

2001-06-22

397

Precision Magnet Measurements for X-Band Accelerator Quadrupole Triplets  

SciTech Connect

An X-band test station is being developed at LLNL to investigate accelerator optimization for future upgrades to mono-energetic gamma-ray (MEGa-Ray) technology at LLNL. Beamline magnets will include an emittance compensation solenoid, windowpane steering dipoles, and quadrupole magnets. Demanding tolerances have been placed on the alignment of these magnets, which directly affects the electron bunch beam quality. A magnet mapping system has been established at LLNL in order to ensure the delivered magnets match their field specification, and the mountings are aligned and capable of reaching the specified alignment tolerances. The magnet measurement system will be described which uses a 3-axis Lakeshore gauss probe mounted on a 3-axis translation stage. Alignment accuracy and precision will be discussed, as well as centering measurements and analysis. The dependence on data analysis over direct multi-pole measurement allows a significant improvement in useful alignment information. Detailed analysis of measurements on the beamline quadrupoles will be discussed, including multi-pole content both from alignment of the magnets, and the intrinsic level of multi-pole magnetic field.

Marsh, R A; Anderson, S G; Armstrong, J P

2012-05-16

398

VIBRATION MEASUREMENTS IN A RHIC QUADRUPOLE AT CRYOGENIC TEMPERATURES.  

SciTech Connect

One of the concerns in using compact superconducting magnets in the final focus region of the ILC is the influence of the cryogen flow on the vibration characteristics. As a first step towards characterizing such motion at nanometer levels, a project was undertaken at BNL to measure the vibrations in a spare RHIC quadrupole under cryogenic conditions. Given the constraints of cryogenic operation, and limited space available, it was decided to use a dual head laser Doppler vibrometer for this work. The performance of the laser vibrometer was tested in a series of room temperature tests and compared with results from Mark L4 geophones. The laser system was then used to measure the vibration of the cold mass of the quadrupole with respect to the outside warm enclosure. These measurements were carried out both with and without the flow of cold helium through the magnet. The results indicate only a minor increase in motion in the horizontal direction (where the cold mass is relatively free to move).

JAIN, A.; AYDIN, S.; HE, P.; ANERELLA, M.; GANETIS, G.; HARRISON, M.; PARKER, B.; PLATE, S.

2005-10-17

399

Performance of Nb3Sn Quadrupole Under High Stress  

SciTech Connect

Future upgrades of the Large Hadron Collider (LHC) will require large aperture and high gradient quadrupoles. Nb{sub 3}Sn is the most viable option for this application but is also known for its strain sensitivity. In high field magnets, with magnetic fields above 12 T, the Lorentz forces will generate mechanical stresses that may exceed 200 MPa in the windings. The existing measurements of critical current versus strain of Nb{sub 3}Sn strands or cables are not easily applicable to magnets. In order to investigate the impact of high mechanical stress on the quench performance, a series of tests was carried out within a LBNL/CERN collaboration using the magnet TQS03 (a LHC Accelerator Research Program (LARP) 1-meter long, 90-mm aperture Nb{sub 3}Sn quadrupole). The magnet was tested four times at CERN under various pre-stress conditions. The average mechanical compressive azimuthal pre-stress on the coil at 4.2 K ranged from 120 MPa to 200 MPa. This paper reports on the magnet performance during the four tests focusing on the relation between pre-stress conditions and the training plateau.

Felice, H.; Bajko, M.; Bingham, B.; Bordini, B.; Bottura, L.; Caspi, S.; Rijk, G. De; Dietderich, D.; Ferracin, P.; Giloux, C.; Godeke, A.; Hafalia, R.; Milanese, A.; Rossi, L.; Sabbi, G. L.

2010-08-01

400

Understanding Leukemias  

NSDL National Science Digital Library

This tutorial is designed to aid medical students at all levels understand the laboratory diagnosis of leukemias. It includes introductory material on the basic laboratory tests specific to diagnoses, their general application and pitfalls in interpretation. The introductory material is followed by a series of short clinical vignettes illustrating the major categories of leukemia. This tutorial focuses on diagnosis and relative little on treatment is included. QuickTime movie player, Flash player and Java script runtime plug-in scripts are required for some pages. The tutorial concludes with a short self-help quiz covering the major points developed. The plug-ins noted above are available free at the following sites: http://www.apple.com/quicktime/download/win.html and http://www.sun.com/ . Questions should be directed to Dr. Mark Braun; braunm@indiana.edu.Annotated: falseDisease diagnosis: neoplastic

Braun, Mark

401

Understanding osteoporosis.  

PubMed Central

Considerable progress has been achieved recently in our understanding of the normal process by which bone mass is regulated. Age-related trabecular bone loss is characterized not simply by a global loss of bone but also by cortical porosity and loss of trabecular connections. Because bone strength depends on architectural as well as material properties, bone quantity alone cannot define fracture risk with precision. Traditional therapies for osteoporosis increase bone mass, and estrogen therapy, in particular, profoundly decreases fracture risk. The pharmacologic restoration of bone quantity and quality, however, remains elusive. Modern biotechnology offers the hope that progress may come about through the development of growth factors and other osteotropic compounds for clinical use. Images PMID:1877231

Marcus, R.

1991-01-01

402

Understanding Condensation  

NSDL National Science Digital Library

Monica Hartman, Assistant Director for Science in St. Clair County, Michigan, conducted this research while she was the learning specialist in a small suburban district just outside a large Midwestern city. While teaching full time in this district she was also completing her doctoral program in education at the University of Michigan. In this chapter, she tells the story of a "science talk" about condensation among fifth graders. She acted as a source and facilitator of change as she and the fifth-grade teacher worked collaboratively to help students share responsibility for their own learning. She describes their continual assessment of student understanding that occurred as their students struggled to explain observations and as they, the teachers, carefully resisted the temptation to end the struggle by saying "that's right!"

Monica Hartman

2007-12-01

403

Aiding understanding  

NASA Astrophysics Data System (ADS)

Research projects carried out by individual researchers or research teams which communicate the challenge and excitement of their work to a wider public are eligible for entry into the 1999 `Partnerships for Public Understanding' awards scheme. This is organized by the Engineering and Physical Sciences Research Council and follows on the success of a pilot scheme launched in 1998 which made 25 grants across the UK. Grant holders are invited to apply for awards to support them in high quality communication projects for the general public, with individual awards normally in the range of £10-20k, but higher awards may be made for exceptional projects. This year a special `Year 2000' PPU sum will be available for a proposal which will contribute significantly to public awareness of the likely impact on society of an aspect of science or engineering research during the first half of the new millennium. The awards have been introduced to support the EPSRC's aim of contributing to public awareness of leading edge research; highly innovative projects will be welcomed, as well as the by now more common activities such as interactive exhibits, public lectures, demonstrations and open days. Applicants should be current holders of EPSRC research grants or fellowships, or those who have held these since 1 April 1994. Proposals will be assessed by EPSRC with advice from communications and education specialists, and the closing date for entries is 1 September 1999. Successful bids will be announced towards the end of the year. Further information on the awards can be obtained from Geoffrey Moore at EPSRC (tel: 01793 444241, e-mail: geoffrey.moore@epsrc.ac.uk), whilst details of the call for proposals can be found on the website at www.epsrc.ac.uk (see pages `Support for public understanding').

1999-07-01

404

Classical trajectories and RRKM modeling of collisional excitation and dissociation of benzylammonium and tert -butyl benzylammonium ions in a quadrupole-hexapole-quadrupole tandem mass spectrometer  

Microsoft Academic Search

Collision-induced dissociation of the benzylammonium and the 4-tert-butyl benzylammonium ions was studied experimentally in an electrospray ionization quadrupole-hexapole-quadrupole tandem\\u000a mass spectrometer. Ion fragmentation efficiencies were determined as functions of the kinetic energy of ions and the collider\\u000a gas (argon) pressure. A theoretical Monte Carlo model of ion collisional excitation, scattering, and decomposition was developed.\\u000a The model includes simulation of the

Vadim D. Knyazev; Stephen E. Stein

2010-01-01

405

Quadrupole Oscillation of a Single-Vortex Bose-Einstein Condensate: Evidence for Kelvin Modes  

Microsoft Academic Search

We study the two transverse quadrupole modes of a cigar-shaped Bose-Einstein condensate with a single centered vortex. We show that the counterrotating mode is more strongly damped than in the absence of a vortex, whereas the corotating mode is not affected appreciably by the vortex. We interpret this result as a decay of the counterrotating quadrupole mode into two excitations

V. Bretin; P. Rosenbusch; F. Chevy; G. V. Shlyapnikov; J. Dalibard

2003-01-01

406

Microwave Collision Diameters II. Theory and Correlation with Molecular Quadrupole Moments  

Microsoft Academic Search

Observed microwave collision diameters are interpreted as arising exclusively from transitions induced during the collision. Collision diameters greater than kinetic theory values arise from dipole-dipole or dipole-quadrupole interactions. The former case affords a quantitative test of the theory. In the latter case measurements of collision diameters yield quadrupole moment measurements which are correlated with molecular structure.

William V. Smith; Raydeen Howard

1950-01-01

407

Analysis of magnetic nanoparticles using quadrupole magnetic field-flow fractionation  

NASA Astrophysics Data System (ADS)

The new technique of quadrupole magnetic field-flow fractionation is described. It is a separation and characterization technique for particulate magnetic materials. Components of a sample are eluted from the separation channel at times dependent on the strength of their interaction with the magnetic field. A quadrupole electromagnet allows a programmed reduction of field strength during analysis of polydisperse samples.

Carpino, Francesca; Moore, Lee R.; Zborowski, Maciej; Chalmers, Jeffrey J.; Williams, P. Stephen

2005-05-01

408

Origin of Low-Energy Quadrupole Collectivity in Vibrational Nuclei H. Fujita,2,3  

E-print Network

Origin of Low-Energy Quadrupole Collectivity in Vibrational Nuclei C. Walz,1 H. Fujita,2,3 A is a separation of energy (respectively momentum) scales such that the high-energy degrees of freedom) energy scale. In the IBM the relevant low-energy degrees of freedom for the description of quadrupole

Ponomarev, Vladimir

409

Automatic Identification of Proteins with a MALDI-Quadrupole Ion Trap Mass Spectrometer  

E-print Network

Automatic Identification of Proteins with a MALDI-Quadrupole Ion Trap Mass Spectrometer Andrew N transmission interface. The ion interface contains a quadrupole ion guide in- stalled between the skimmer, automatic identification of proteins. A mass spectrometry-based method can satisfy this need if it (1

Chait, Brian T.

410

Closed forms for the matrix elements of the quadrupole collective operators  

Microsoft Academic Search

Compact analytical expressions for the matrix elements for the spherical phonon operators and the elementary anharmonicities in a basis of explicit eigenfunctions of the harmonic quadrupole collective Hamiltonian are established. An algorithm for the calculation of the matrix elements of any many-phonon quadrupole operator is also presented.

A. A. Raduta; V. Ceausescu; A. Gheorghe

1978-01-01

411

Cyclotron-resonance maser in a periodically loaded quadrupole transmission line Y. Leibovitch and E. Jerby*  

E-print Network

Cyclotron-resonance maser in a periodically loaded quadrupole transmission line Y. Leibovitch and E; revised manuscript received 17 February 1999 A cyclotron-resonance maser CRM is implemented in a periodic quadrupole waveguide. The device oscillates at the fundamental and high harmonics of the cyclotron frequency

Jerby, Eli

412

Test Results of a Superconducting Quadrupole Model Designed for Linear Accelerator Applications  

SciTech Connect

The first model of a superconducting quadrupole for use in a Linear Accelerator was designed, built and tested at Fermilab. The quadrupole has a 78 mm aperture, and a cold mass length of 680 mm. A superferric magnet configuration with iron poles and four racetrack coils was chosen based on magnet performance, cost, and reliability considerations. Each coil is wound using enamel insulated, 0.5 mm diameter, NbTi superconductor. The quadrupole package also includes racetrack type dipole steering coils. The results of the quadrupole design, manufacturing and test, are presented. Specific issues related to the quadrupole magnetic center stability, superconductor magnetization and mechanical stability are discussed. The magnet quench performance and results of magnetic measurements will also be briefly discussed.

Kashikhin, Vladimir S.; Andreev, Nikolai; Chlachidze, Guram; DiMarco, Joseph; Kashikhin, Vadim V.; Lamm, Michael J.; Lopes, Mauricio L.; Orris, Darryl; Tartaglia, Michael; Tompkins, John C.; Velev, Gueorgui; /Fermilab

2008-08-01

413

Anomaly-induced quadrupole moment of the neutron in magnetic field  

SciTech Connect

Neutrons cannot possess a quadrupole moment in the vacuum. Nevertheless, we show that, in the presence of an external magnetic field, the neutrons acquire a new type of quadrupole moment Q{sup ij} = {chi}{sigma}{sup i} B{sup j} involving the components of spin and magnetic field. This 'chiral magnetic' quadrupole moment arises from the interplay of the chiral anomaly and the magnetic field; we estimate its value for the neutron in the static limit and find {chi} {approx_equal} 1.35 {center_dot} 10{sup -2} fm{sup 4}. The detection of the quadrupole moment of the neutron would provide a novel test of the role of the chiral anomaly in low-energy QCD and can be possible in the presence of both magnetic and inhomogeneous electric fields. The quadrupole moment of the neutron may affect, e.g., the properties of neutron stars and magnetars.

Kharzeev, D.E.; Yee, H.-U., Zahed, I.

2011-08-18

414

Miniature micromachined quadrupole mass spectrometer array and method of making the same  

NASA Technical Reports Server (NTRS)

The present invention provides a quadrupole mass spectrometer and an ion filter for use in the quadrupole mass spectrometer. The ion filter includes a thin patterned layer including a two-dimensional array of poles forming one or more quadrupoles. The patterned layer design permits the use of very short poles and with a very dense spacing of the poles, so that the ion filter may be made very small. Also provided is a method for making the ion filter and the quadrupole mass spectrometer. The method involves forming the patterned layer of the ion filter in such a way that as the poles of the patterned layer are formed, they have the relative positioning and aligrnent for use in a final quadrupole mass spectrometer device.

Chutjian, Ara (Inventor); Hecht, Michael (Inventor); Orient, Otto (Inventor); Wiberg, Dean (Inventor); Brennen, Reid A. (Inventor)

2001-01-01

415

Miniature micromachined quadrupole mass spectrometer array and method of making the same  

NASA Technical Reports Server (NTRS)

The present invention provides a quadrupole mass spectrometer and an ion filter for use in the quadrupole mass spectrometer. The ion filter includes a thin patterned layer including a two-dimensional array of poles forming one or more quadrupoles. The patterned layer design permits the use of very short poles and with a very dense spacing of the poles, so that the ion filter may be made very small. Also provided is a method for making the ion filter and the quadrupole mass spectrometer. The method involves forming the patterned layer of the ion filter in such a way that as the poles of the patterned layer are formed, they have the relative positioning and alignment for use in a final quadrupole mass spectrometer device.

Chutjian, Ara (Inventor); Hecht, Michael (Inventor); Orient, Otto (Inventor); Wiberg, Dean (Inventor); Brennen, Reid A. (Inventor)

2001-01-01

416

Miniature micromachined quadrupole mass spectrometer array and method of making the same  

NASA Technical Reports Server (NTRS)

The present invention provides a quadrupole mass spectrometer and an ion filter for use in the quadrupole mass spectrometer. The ion filter includes a thin patterned layer including a two-dimensional array of poles forming one or more quadrupoles. The patterned layer design permits the use of very short poles and with a very dense spacing of the poles, so that the ion filter may be made very small. Also provided is a method for making the ion filter and the quadrupole mass spectrometer. The method involves forming the patterned layer of the ion filter in such a way that as the poles of the patterned layer are formed, they have the relative positioning and alignment for use in a final quadrupole mass spectrometer device.

Chutjian, Ara (Inventor); Hecht, Michael (Inventor); Orient, Otto (Inventor); Wiberg, Dean (Inventor); Brennen, Reid A. (Inventor)

2000-01-01

417

Miniature micromachined quadrupole mass spectrometer array and method of making the same  

NASA Technical Reports Server (NTRS)

The present invention provides a quadrupole mass spectrometer and an ion filter, or pole array, for use in the quadrupole mass spectrometer. The ion filter includes a thin patterned layer including a two-dimensional array of poles forming one or more quadrupoles. The patterned layer design permits the use of very short poles and with a very dense spacing of the poles, so that the ion filter may be made very small. Also provided is a method for making the ion filter and the quadrupole mass spectrometer. The method involves forming the patterned layer of the ion filter in such a way that as the poles of the patterned layer are formed, they have the relative positioning and alignment for use in a final quadrupole mass spectrometer device.

Chutjian, Ara (Inventor); Fuerstenau, Stephen D. (Inventor); Orient, Otto J. (Inventor); Yee, Karl Y. (Inventor); Rice, John T. (Inventor)

2000-01-01

418

Miniature micromachined quadrupole mass spectrometer array and method of making the same  

NASA Technical Reports Server (NTRS)

The present invention provides a quadrupole mass spectrometer and an ion filter, or pole array, for use in the quadrupole mass spectrometer. The ion filter includes a thin patterned layer including a two-dimensional array of poles forming one or more quadrupoles. The patterned layer design permits the use of very short poles and with a very dense spacing of the poles, so that the ion filter may be made very small. Also provided is a method for making the ion filter and the quadrupole mass spectrometer. The method involves forming the patterned layer of the ion filter in such a way that as the poles of the patterned layer are formed, they have the relative positioning and alignment for use in a final quadrupole mass spectrometer device.

Chutjian, Ara (Inventor); Fuerstenau, Stephen D. (Inventor); Orient, Otto J. (Inventor); Yee, Karl Y. (Inventor); Rice, John T. (Inventor)

2002-01-01

419

Miniature micromachined quadrupole mass spectrometer array and method of making the same  

NASA Technical Reports Server (NTRS)

The present invention provides a quadrupole mass spectrometer and an ion filter, or pole array, for use in the quadrupole mass spectrometer. The ion filter includes a thin patterned layer including a two-dimensional array of poles forming one or more quadrupoles. The patterned layer design permits the use of very short poles and with a very dense spacing of the poles, so that the ion filter may be made very small. Also provided is a method for making the ion filter and the quadrupole mass spectrometer. The method involves forming the patterned layer of the ion filter in such a way that as the poles of the patterned layer are formed, they have the relative positioning and alignment for use in a final quadrupole mass spectrometer device.

Chutjian, Ara (Inventor); Fuerstenau, Stephen D. (Inventor); Orient, Otto J. (Inventor); Yee, Karl Y. (Inventor); Rice, John T. (Inventor)

2001-01-01

420

A superconducting quadrupole magnet array for a heavy ion fusion driver  

SciTech Connect

A multi-channel quadrupole array has been proposed to increase beam intensity and reduce space charge effects in a Heavy Ion Fusion Driver. A single array unit composed of several quadrupole magnets, each with its own beam line, will be placed within a ferromagnetic accelerating core whose cost is directly affected by the array size. A large number of focusing arrays will be needed along the accelerating path. The use of a superconducting quadrupole magnet array will increase the field and reduce overall cost. We report here on the design of a compact 3 x 3 superconducting quadrupole magnet array. The overall array diameter and length including the cryostat is 900 x 700 mm. Each of the 9 quadrupole magnets has a 78 mm warm bore and an operating gradient of 50 T/m over an effective magnetic length of 320 mm.

Caspi, S.; Bangerter, r.; Chow, K.; Faltens, A.; Gourley, S.; Hinkins, R.; Gupta, R.; Lee, E.; McInturff, A.; Scanlan, R.; Taylor, C.; Wolgast, D.

2000-06-27

421

Problematic Aspects of Nuclear Education.  

ERIC Educational Resources Information Center

Reviewing research on children's understanding of nuclear war, Tizard suggests that educators and researchers have yet to understand the factors influencing children's attitudes, anxieties, and knowledge of nuclear issues. (Author/SK)

Tizard, Barbara

1984-01-01

422

Understanding Genetics  

NSDL National Science Digital Library

While most people may retain a smattering of information and basic concepts about the field of genetics, some may also wish to refresh their knowledge base, and the Understanding Genetics website is a fine way to get back up to speed. Created and maintained by the good people at the Tech Museum of Innovation in San Jose, the homepage is well thought out, and provides a nice entry point to many of the features available here. Visitors can peruse the questions posed to geneticists in the "Ask a Geneticist" feature, browse a selection of recent news stories regarding genetics, and take a survey on the ethical questions posed by the issues of stem cell research and genetically modified foods. The feature story is a fine resource as well, as it provides basic, non-jargon-laden answers to such question as "What is a gene?" and "How do genes work?". The site also contains a number of activities that can be done at home, including a fun exercise that teaches users how to extract DNA from strawberries.

423

Nuclear Deformation Effects in the Cluster Radioactivity  

Microsoft Academic Search

We investigate the influence of the nuclear deformation on the decay rates of\\u000asome cluster emission processes. The interaction between the daughter and the\\u000acluster is given by a double folding potential including quadrupole and\\u000ahexadecupole deformed densities of both fragments. The nuclear part of the\\u000anucleus-nucleus interaction is density dependent and at small distances a\\u000arepulsive core in the

S. Misicu; D. Protopopescu

1998-01-01

424

COMPENSATION OF FAST KICKER ROLLS WITH SKEW QUADRUPOLES  

SciTech Connect

The development of the third generation light sources lead to the implementation of the top-up operation, when injection occurs while users collect data. The beam excursions due to the non-closure of the injection bump can spoil the data and need to be suppressed. In the horizontal plane compensation can be achieved by adjusting timing and kick amplitudes. The rolls of the kicker magnets create non-closure in the vertical plane and usually there is no means for correction. In the paper we describe proposed compensation scheme utilizing two skew quadrupoles placed inside the injection bump. The third generation light sources implement top-up operation firstly introduced at Advanced Photon Source. In this mode the circulating beam current is supported near constant by frequent injection of small charge, while photon beam is delivered for users. The beam perturbations caused by the mismatched injection bump can provide undesired noise in the user data. Usually the injection trigger is distributed to the users end stations so that those affected would be able to blank data acquisition. Nevertheless, as good operational practice such transients should be suppressed as much as possible. In the horizontal plane (which is commonly used for injection) one can adjust individual kicker strength as well as trigger delay while observing motion of the stored beam centroid. In the vertical plane such means are unavailable in the most cases. The possible solutions include dedicated weak vertical kickers and motorized adjustment of the roll angle of the injection kickers. Both abovementioned approaches are expensive and can significantly deteriorate reliability. We suggest two employ two skew quadrupoles (to correct both angle and position) placed inside the injection bump. In this case the beam position itself serves as measure of the kicker strength (assuming that kickers are well matched) and vertical kicks from the skew quadrupoles will be self synchronized with injection bump. In this paper we will consider the case when injection hardware (kickers and septa) are located in the same straight. Such an approach simplifies consideration but it can be generalized.

Pinayev, I.

2011-03-28

425

174 Anal. Chem. 1991. 63.174-178 Use of a Single-Quadrupole Mass Spectrometer for  

E-print Network

collisional activation in two regions of a triple-quadrupole mass spec- trometer: (a) in the region between174 Anal. Chem. 1991. 63.174-178 Use of a Single-Quadrupole Mass Spectrometer for Collision by eiectrospray ionization in a simple and inexpensive singie- quadrupole mass spectrometer Is demonstrated

Chait, Brian T.

426

A Cryogenic test stand for LHC quadrupole magnets  

SciTech Connect

A new test stand for testing LHC interaction region (IR) quadrupole magnets at the Fermilab Magnet Test Facility has been designed and operated. The test stand uses a double bath system with a lambda plate to provide the magnet with a stagnant bath of pressurized He II at 1.9 K and 0.13 MPa. A cryostated magnet 0.91 m in diameter and up to 13 m in length can be accommodated. This paper describes the system design and operation. Issues related to both 4.5 K and 1.9 K operations and magnet quenching are highlighted. An overview of the data acquisition and cryogenics controls systems is also included.

R. J. Rabehl et al.

2004-03-09

427

Investigation of a quadrupole ultra-high vacuum ion pump  

NASA Technical Reports Server (NTRS)

The new nonmagnetic ion pump resembles the quadrupole ionization gage. The dimensions are larger, and hyperbolically shaped electrodes replace the four rods. Their surfaces follow y sq. = 36 + x sq. (x, y in centimeters). The electrodes, 55 cm long, are positioned lengthwise in a tube. At one end a cathode emits electrons; at the other end a narrowly wound flat spiral of tungsten clad with titanium on cathode potential can be heated for titanium evaporation. Electrons accelerated by a dc potential of the surface electrodes oscillate between the ends on rotational trajectories, if a high frequency potential superimposed on the dc potential is properly adjusted. Pumping speeds (4-100 liter/sec) for different gases at different peak voltages (1000-3000V) at corresponding frequencies (57-100 MHz), and at different pressures 0.00001 to the minus 9 power Torr were observed. The lowest pressure reached was below 10 to the minus 10 power Torr.

Schwarz, H. J.

1974-01-01

428

Super Strong Permanent Magnet Quadrupole for a Linear Collider  

SciTech Connect

The field strength generated by permanent magnets has been further extended by the introduction of saturated iron. A permanent magnet quadrupole (PMQ) lens with such saturated iron is one of the candidates for the final focus lens for an e{sup +}e{sup -} Linear Collider accelerator, because of its compactness and low power consumption. The first prototype of the PMQ has been fabricated and demonstrated to have an integrated strength of 28.5T with an overall length of 10 cm and a 7mm bore radius. Two drawbacks should be considered: its negative temperature coefficient of field strength and its fixed strength. A thermal compensation material is being tested to cure the first problem. The other problem may be solved by rotating sectioned magnet bricks, but that may lead to movement of the magnetic center and introduction of multipoles beyond some strict requirements.

Mihara, Takanori

2004-02-19

429

Plasma-beam traps and radiofrequency quadrupole beam coolers  

SciTech Connect

Two linear trap devices for particle beam manipulation (including emittance reduction, cooling, control of instabilities, dust dynamics, and non-neutral plasmas) are here presented, namely, a radiofrequency quadrupole (RFQ) beam cooler and a compact Penning trap with a dust injector. Both beam dynamics studies by means of dedicated codes including the interaction of the ions with a buffer gas (up to 3 Pa pressure), and the electromagnetic design of the RFQ beam cooler are reported. The compact multipurpose Penning trap is aimed to the study of multispecies charged particle samples, primarily electron beams interacting with a background gas and/or a micrometric dust contaminant. Using a 0.9 T solenoid and an electrode stack where both static and RF electric fields can be applied, both beam transport and confinement operations will be available. The design of the apparatus is presented.

Maggiore, M., E-mail: mario.maggiore@lnl.infn.it; Cavenago, M.; Comunian, M.; Chirulotto, F.; Galatà, A.; De Lazzari, M.; Porcellato, A. M.; Roncolato, C.; Stark, S. [INFN-LNL, viale dell’Università 2, 35020 Legnaro (Italy)] [INFN-LNL, viale dell’Università 2, 35020 Legnaro (Italy); Caruso, A.; Longhitano, A. [INFN-LNS, via S. Sofia 54, 95123 Catania (Italy)] [INFN-LNS, via S. Sofia 54, 95123 Catania (Italy); Cavaliere, F.; Maero, G.; Paroli, B.; Pozzoli, R.; Romé, M. [INFN Sezione di Milano and Dipartimento di Fisica, Università degli Studi di Milano, via Celoria 16, 20133 Milano (Italy)] [INFN Sezione di Milano and Dipartimento di Fisica, Università degli Studi di Milano, via Celoria 16, 20133 Milano (Italy)

2014-02-15

430

Plasma-beam traps and radiofrequency quadrupole beam coolers.  

PubMed

Two linear trap devices for particle beam manipulation (including emittance reduction, cooling, control of instabilities, dust dynamics, and non-neutral plasmas) are here presented, namely, a radiofrequency quadrupole (RFQ) beam cooler and a compact Penning trap with a dust injector. Both beam dynamics studies by means of dedicated codes including the interaction of the ions with a buffer gas (up to 3 Pa pressure), and the electromagnetic design of the RFQ beam cooler are reported. The compact multipurpose Penning trap is aimed to the study of multispecies charged particle samples, primarily electron beams interacting with a background gas and/or a micrometric dust contaminant. Using a 0.9 T solenoid and an electrode stack where both static and RF electric fields can be applied, both beam transport and confinement operations will be available. The design of the apparatus is presented. PMID:24593614

Maggiore, M; Cavenago, M; Comunian, M; Chirulotto, F; Galatà, A; De Lazzari, M; Porcellato, A M; Roncolato, C; Stark, S; Caruso, A; Longhitano, A; Cavaliere, F; Maero, G; Paroli, B; Pozzoli, R; Romé, M

2014-02-01

431

Alternative Mechanical Structure for LARP Nb3Sn Quadrupoles  

SciTech Connect

An alternative structure for the 120 mm Nb{sub 3}Sn quadrupole magnet presently under development for use in the upgrade for LHC at CERN is presented. The goals of this structure are to build on the existing technology developed in LARP with the LQ and HQ series magnets and to further optimize the features required for operation in the accelerator. These features include mechanical alignment needed for field quality and provisions for cold mass cooling with 1.9 K helium in a helium pressure vessel. The structure will also optimize coil azimuthal and axial pre-load for high gradient operation, and will incorporate features intended to improve manufacturability, thereby improving reliability and reducing cost.

Anerella, M.; Cozzolino, J.; Ambrosio, G.; Caspi, S.; Felice, H.; Kovach, P.; Lamm, M.; Sabbi, G.; Schmalzle, J.; Wanderer, P.

2010-08-01

432

Nb3Sn Quadrupole Magnets for the LHC IR  

SciTech Connect

The development of insertion quadrupoles with 205 T/m gradient and 90 mm bore represents a promising strategy to achieve the ultimate luminosity goal of 2.5 x 10{sup 34} cm{sup -2}s{sup -1} at the Large Hadron Collider (LHC). At present, Nb{sub 3}Sn is the only practical conductor which can meet these requirements. Since Nb{sub 3}Sn is brittle, and considerably more strain sensitive than NbTi, the design concepts and fabrication techniques developed for NbTi magnets need to be modified appropriately. In addition, IR magnets must provide high field quality and operate reliably under severe radiation loads. The results of conceptual design studies addressing these issues are presented.

Sabbi, G.; Caspi, S.; Chiesa, L.; Coccoli, M.; Dietderich, D.r.; Ferracin, P.; Gourlay, S.A.; Hafalia, R.R.; Lietzke, A.F.; McInturff, A.D.; Scanlan, R.M.

2001-08-01

433

Field Quality Study of the LARP Nb3Sn 3.7m-Long Quadrupole Models of LQ Series  

SciTech Connect

After the successful test of the first long Nb{sub 3}Sn quadrupole magnet (LQS01), the US LHC Accelerator Research Program (LARP) has assembled and tested a new 3.7 m-long Nb{sub 3}Sn quadrupole (LQS02). This magnet has four new coils made of the same conductor as LQS01 coils, and it is using the same support structure. LQS02 was tested at the Fermilab Vertical Magnet Test Facility with the main goal to confirm that the long models can achieve field gradient above 200 T/m, LARP target for 90-mm aperture, as well as to measure the field quality. These long models lack some alignment features and it is important to study the field harmonics. Previous field quality measurements of LQS01 showed higher than expected differences between measured and calculated harmonics compared to the short models (TQS) assembled in a similar structure. These differences could be explained by the use of two different impregnation fixtures during coil fabrication. In this paper, we present a comparison of the field quality measurements between LQS01 and LQS02 as well as a comparison with the short TQS models. If the result supports the coil fabrication hypothesis, another LQS assembly with all coils fabricated in the same fixture will be produced for understanding the cause of the discrepancy between short and long models.

AMbrosio, G.; Andreev, N.; Bossert, R.; Chlachidze, G.; DiMarco, J.; Kashikhin, V.V.; Lamm, M.J.; Nobrega, F.; Prebys, E.; Sylvester, C.; Tartaglia, M.; /Fermilab /LBL, Berkeley /Brookhaven

2011-09-01

434

Electric quadrupole moments and strong interaction effects in pionic atoms of /sup 165/Ho, /sup 175/Lu, /sup 176/Lu, /sup 179/Hf and /sup 181/Ta  

SciTech Connect

The effective quadrupole moments Q/sub eff/ of the nuclei of /sup 165/Ho, /sup 175/Lu, /sup 176/Lu, /sup 179/Hf and /sup 181/Ta were accurately measured by detecting the pionic atom 5g-4f x-rays of the elements. The spectroscopic quadrupole moments, Q/sub spec/, were obtained by correcting Q/sub eff/ for nuclear finite size effect, distortion of the pion wave function by the pion-nucleus strong interaction, and contribution to the energy level splittings by the strong interaction. The intrinsic quadrupole moments, Q/sub 0/, were obtained by projecting Q/sub spec/ into the frame of reference fixed on the nucleus. The shift, epsilon/sub 0/, and broadening, GAMMA/sub 0/, of the 4f energy level for all the elements were also measured. Theoretical values of epsilon/sub 0/ and GAMMA/sub 0/ were calculated and compared to the experimental values. The measured values of Q/sub 0/ were compared with existing results in muonic and pionic atoms. The measured values of epsilon/sub 0/ and GAMMA/sub 0/ were also compared with existing values.

Olaniyi, B.H.

1980-01-01

435

Nuclear Structure of {sup 231}Ra  

SciTech Connect

The study of the upper border of the octupole deformation region near A=225, where the octupole deformation vanishes in the presence of a well developed quadrupole field, is of great relevance in order to understand the interplay of octupole and quadrupole collectivities. Within the IS322 collaboration at CERN we carry out a systematic investigation of the heavy Fr - Th nuclei that presently includes {sup 227}Fr, {sup 227,228,229}Ra, {sup 229}Ac and {sup 229,231}Th. The heaviest Ra isotope we have studied so far and in which the fast timing {beta}{gamma}{gamma}(t) method has been applied is {sup 231}Ra.

Boutami, R.; Fraile, L.M.; Borge, M.J.G.; Aas, A.J.; Fogelberg, B.; Garcia-Raffi, L.M.; Grant, I.S.; Gulda, K.; Hagebo, E.; Kurcewicz, W.; Lopez-Jimenez, M.J.; Lovhoiden, G.; Mach, H.; Martinez, T.; Rubio, B.; Tain, J.L.; Teijeiro, A.G.; Tengblad, O.; Thorsteinsen, T.F.

1999-12-31

436

Nuclear structure of {sup 231}Ra  

SciTech Connect

The study of the upper border of the octupole deformation region near A=225, where the octupole deformation vanishes in the presence of a well developed quadrupole field, is of great relevance in order to understand the interplay of octupole and quadrupole collectivities. Within the IS322 collaboration at CERN we carry out a systematic investigation of the heavy Fr-Th nuclei that presently includes {sup 227}Fr, {sup 227,228,229}Ra, {sup 229}Ac and {sup 229,231}Th. The heaviest Ra isotope we have studied so far and in which the fast timing {beta}{gamma}{gamma}(t) method has been applied is {sup 231}Ra.

Boutami, R.; Fraile, L. M.; Borge, M. J. G.; Lopez-Jimenez, M. J.; Teijeiro, A. G. [Instituto de Estructura de la Materia, CSIC, Serrano 113 bis, E-28006 Madrid (Spain); Aas, A. J.; Hageboe, E. [Department of Chemistry, Univ. of Oslo, P.O. Box 1033, Blindern, N-0315 Oslo (Norway); Fogelberg, B.; Mach, H. [Department of Neutron Research, Univ. of Uppsala, S-61182 Nykoeping (Sweden); Garcia-Raffi, L. M.; Martinez, T.; Rubio, B.; Tain, J. L. [Instituto de Fisica Corpuscular, CSIC-Univ. Valencia, E-46100 Burjassot (Spain); Grant, I. S. [Schuster Laboratory, Univ. of Manchester, Manchester M13 9PL (United Kingdom); Gulda, K.; Kurcewicz, W. [Department of Physics, Univ. of Warsaw, Pl-00 681 Warsaw (Poland); Loevhoeiden, G. [Department of Physics, Univ. of Oslo, P.O. Box 1048, Blindern, N-0316 Oslo (Norway); Tengblad, O. [Instituto de Estructura de la Materia, CSIC, Serrano 113 bis, E-28006 Madrid (Spain); EP Division, CERN, CH-1211 Geneva 23 (Switzerland); Thorsteinsen, T. F. [Department of Physics, Univ. of Bergen, N-5000 Bergen (Norway)

1999-11-16

437

Measurement of the Electric Quadrupole Moment of the 9/2- and 21/2- Isomers in 173Ta  

NASA Astrophysics Data System (ADS)

The electric quadrupole moments of the 9/2- and 21/2- isomeric states of 173Ta at 165.8 keV and 1713.2 keV, respectively, were measured as Q(9/2-)=2.92(15) b and Q(21/2-)=6.23(18) b for the first time using the TDPAD technique. A 66 MeV pulsed 12C ion beam from the 15UD pelletron accelerator facility of the Nuclear Science Centre at New Delhi was used in the reaction 165Ho(12C, 4n?)173Ta. The experimental values of equilibrium deformations ?2(9/2-)=0.251(7) and ?2(21/2-)=0.391(7) were extracted.

Thakur, P.; Dogra, R.; Bhati, A. K.; Bedi, S. C.; Singh, R. P.; Muralithar, S.; Bhowmik, R. K.

2000-12-01

438

Overcoming field imperfections of quadrupole mass filters with mass analysis in islands of stability.  

PubMed

We have constructed, and tested as mass filters, linear quadrupoles with added hexapole fields of 4%, 8%, and 12%, with and without added octopole fields. A hexapole field can be added to the field of a linear quadrupole by rotating the two y rods toward an x rod. This also adds an octopole field which can be removed by making the x rods greater in diameter than the y rods. In comparison to conventional quadrupole mass filters these rod sets have severely distorted quadrupole fields, with a mix of both even and odd higher spatial harmonics. They allow evaluating the performance of rod sets with strong geometric and field distortions as mass filters. Conventional mass analysis at the tip of the stability diagram has been compared to mass analysis using islands of stability. The stability islands are produced by applying an auxiliary quadrupole excitation field to the quadrupole. We show that with normal mass analysis at the tip of the stability diagram, the transmission, resolution, and peak shapes are relatively poor in comparison to a conventional rod set. However, the use of islands of stability dramatically improves the resolution and peak shape, and in some cases ion transmission, suggesting that mass analysis with islands of stability may provide a method to overcome a wide range of field imperfections in linear quadrupole mass filters. PMID:19522524

Zhao, XianZhen; Xiao, Zilan; Douglas, D J

2009-07-15

439

Linear trap with three orthogonal quadrupole fields for dust charging experiments  

SciTech Connect

Investigations of charging processes on a single dust grain under controlled conditions in laboratory experiments are the unique way to understand the behavior of dust grains in complex plasma (in space, in laboratory, or in technological applications). An electrodynamic trap is often utilized for both holding a single grain and continuously measuring its charge-to-mass ratio. We propose a modified design of the linear quadrupole trap with the electrodes split into two parts; each of them being supplied by a designated source. The paper presents basic calculations and the results of the trap prototype tests. These tests have confirmed our expectations and have shown that the suggested solution is fully applicable for the dust charging experiments. The uncertainty of determination of the dust grain charge does not exceed 10{sup -3}. The main advantages of the suggested design in comparison with other traps used for dust investigations can be summarized as: The trap (i) is more opened, thus it is suitable for a simultaneous application of the ion and electron beams and UV source; (ii) facilitates investigations of dust grains in a broader range of parameters; and (iii) allows the grain to move along the axis in a controlled way.

Beranek, Martin; Nemecek, Zdenek; Safrankova, Jana; Jerab, Martin; Pavlu, Jiri [Charles University, Faculty of Mathematics and Physics, Prague (Czech Republic); Cermak, Ivo [CGC Instruments, Chemnitz (Germany)

2012-11-15

440

Matching an H- beam into a radio frequency quadrupole at Rutherford Appleton Laboratory  

NASA Astrophysics Data System (ADS)

A major component of work being carried out to upgrade the ISIS spallation neutron source at Rutherford Appleton Laboratory (RAL) is the Front End Test Stand (FETS). FETS is aimed at improving the luminosity of the linac, and consists of a Penning ion source, Low Energy Beam Transport (LEBT), Radio Frequency Quadrupole (RFQ), and Medium Energy Beam Transport (MEBT). It may serve as a first part of the accelerator chain providing a 60 mA, 3 MeV H- beam up to a 10% duty cycle. The current output of the source and the transmission of the LEBT are reasonable, but there are issues with the alignment to provide a centred beam matched into the acceptance of the RFQ. Improvements have been made to the post acceleration to address this problem. Measurements with a collimated beam have been performed to understand the behaviour of the solenoids and steerer magnets. Comparing these results with simulations proved that, besides possible mechanical imperfections of the ion source and post acceleration assembly, agreement can only be achieved if the magnetic fields are distorted.

Gabor, C.; Back, J. J.; Faircloth, D. C.; Lawrie, S. R.; Letchford, A. P.

2014-02-01

441

Matching an H(-) beam into a radio frequency quadrupole at Rutherford Appleton Laboratory.  

PubMed

A major component of work being carried out to upgrade the ISIS spallation neutron source at Rutherford Appleton Laboratory (RAL) is the Front End Test Stand (FETS). FETS is aimed at improving the luminosity of the linac, and consists of a Penning ion source, Low Energy Beam Transport (LEBT), Radio Frequency Quadrupole (RFQ), and Medium Energy Beam Transport (MEBT). It may serve as a first part of the accelerator chain providing a 60 mA, 3 MeV H(-) beam up to a 10% duty cycle. The current output of the source and the transmission of the LEBT are reasonable, but there are issues with the alignment to provide a centred beam matched into the acceptance of the RFQ. Improvements have been made to the post acceleration to address this problem. Measurements with a collimated beam have been performed to understand the behaviour of the solenoids and steerer magnets. Comparing these results with simulations proved that, besides possible mechanical imperfections of the ion source and post acceleration assembly, agreement can only be achieved if the magnetic fields are distorted. PMID:24593479

Gabor, C; Back, J J; Faircloth, D C; Lawrie, S R; Letchford, A P

2014-02-01

442

Development of a GC/Quadrupole-Orbitrap mass spectrometer, part II: new approaches for discovery metabolomics.  

PubMed

Identification of unknown peaks in gas chromatography/mass spectrometry (GC/MS)-based discovery metabolomics is challenging, and remains necessary to permit discovery of novel or unexpected metabolites that may elucidate disease processes and/or further our understanding of how genotypes relate to phenotypes. Here, we introduce two new technologies and an analytical workflow that can facilitate the identification of unknown peaks. First, we report on a GC/Quadrupole-Orbitrap mass spectrometer that provides high mass accuracy, high resolution, and high sensitivity analyte detection. Second, with an "intelligent" data-dependent algorithm, termed molecular-ion directed acquisition (MIDA), we maximize the information content generated from unsupervised tandem MS (MS/MS) and selected ion monitoring (SIM) by directing the MS to target the ions of greatest information content, that is, the most-intact ionic species. We combine these technologies with (13)C- and (15)N-metabolic labeling, multiple derivatization and ionization types, and heuristic filtering of candidate elemental compositions to achieve (1) MS/MS spectra of nearly all intact ion species for structural elucidation, (2) knowledge of carbon and nitrogen atom content for every ion in MS and MS/MS spectra, (3) relative quantification between alternatively labeled samples, and (4) unambiguous annotation of elemental composition. PMID:25166283

Peterson, Amelia C; Balloon, Allison J; Westphall, Michael S; Coon, Joshua J

2014-10-21

443

Nuclear Magnetic Resonance Spectroscopy  

NSDL National Science Digital Library

This website serves as a primer for understanding the fundamentals of NMR spectroscopy. Plenty of useful figures and animations that enhance the understanding of nuclear spin, shielding, and how these phenomena serve as the basis for NMR.

2011-05-18

444

Study of electric quadrupole interactions at 111Cd on Zn sites in RZn (R = Ce, Gd, Tb, Dy) compounds using the PAC spectroscopy  

NASA Astrophysics Data System (ADS)

Nuclear quadrupole interactions at Zn sites in the intermetallic compounds RZn (R = Ce, Gd, Tb, Dy) have been investigated by perturbed gamma-gamma angular correlation (PAC) spectroscopy using 111In(111Cd) as probe nuclei. Measurements were carried out in the temperature range of 10-295 K. These compounds exhibit CsCl type cubic structure and while CeZn shows antiferromagnetic behaviour, the compounds GdZn, TbZn, DyZn are ferromagnetic. The results show that the EFG in these compounds is sensitive to the distribution of rare-earth 4f-electron charges.

Bosch-Santos, Brianna; Carbonari, Artur W.; Cabrera-Pasca, Gabriel A.; Costa, Messias S.; Saxena, Rajendra N.

2013-05-01

445

Investigation of hyperfine quadrupole interactions in UGe2 and UAl2 compounds on 111Cd probe nuclei by the perturbed angular correlation method  

NASA Astrophysics Data System (ADS)

The parameters of nuclear quadrupole hyperfine interaction in intermetallic UGe2 and UAl2 compounds have been measured in a temperature range of 100-300 K using the perturbed angular ?? correlation method on 111Cd probe nuclei. The results obtained for UGe2 indicate a pronounced anisotropic character in the distribution of f electrons in agreement with the calculation of the electronic structure of this compound. The hybridization degree between f electrons of U and p electrons of Al in UAl2 is lower than the hybridization degree between f electrons of U and p electrons of Ge in UGe2.

Tsvyashchenko, A. V.; Fomicheva, L. N.; Salamatin, A. V.; Velichkov, A. I.; Kochetov, O. I.; Ryasny, G. K.; Sorokin, A. A.; Budzynski, M.

2009-05-01

446

Alternate Oscillation between Scissors and Quadrupole Modes in Sodium Bose–Einstein Condensates  

NASA Astrophysics Data System (ADS)

Using an additional off-axis Helmholtz coil, we modulated the strength of a magnetic field at the center of a cloverleaf trap for sodium Bose-Einstein condensates so that it passed through zero for a few milliseconds. At a modulation time of 1 ms, a scissors mode and a high-lying quadrupole mode were generated independently, which had the same Landau damping rates of 39(10) 1/s. However, at 2 ms, alternate oscillation between the scissors mode and the high-lying quadrupole mode, whose frequency was twice that of the scissors mode, was observed with the frequency of the low-lying quadrupole mode.

Yamazaki, Masahiro; Wakayama, Kazuki; Harada, Miho; Morinaga, Atsuo

2015-04-01

447

Temperature and angular momentum dependence of the quadrupole deformation in sd-shell  

E-print Network

Temperature and angular momentum dependence of the quadrupole deformation is studied in the middle of the sd-shell for 28Si and 27Si isotopes using the spherical shell model approach. The shell model calculations have been performed using the standard USD interaction and the canonical partition function constructed from the calculated eigen-solutions. It is shown that the extracted average quadrupole moments show a transitional behavior as a function of temperature and the inferred transitional temperature is shown to vary with angular-momentum. The quadrupole deformation of the individual eigen-states is also analyzed.

P. A. Ganai; J. A. Sheikh; I. Maqbool; R. P. Singh

2009-06-16

448

Electric quadrupole transition probabilities and line strengths of Ti{sup 11+}  

SciTech Connect

Electric quadrupole transition probabilities and line strengths have been calculated using the weakest bound electron potential model for sodium-like titanium, considering many transition arrays. We employed numerical Coulomb approximation and non-relativistic Hartree–Fock wavefunctions for the expectation values of radii in determination of parameters of the model. The necessary energy values have been taken from experimental data in the literature. The calculated electric quadrupole line strengths have been compared with available data in the literature and good agreement has been obtained. Moreover, some electric quadrupole transition probability and line strength values not existing in the literature for some highly excited levels have been obtained using this method.

Gökçe, Yasin, E-mail: ygokce58@gmail.com [Department of Physics, Faculty of Science, Karamanoglu Mehmetbey University, Karaman (Turkey); Çelik, Gültekin [Department of Physics, Faculty of Science, Selçuk University, Campus 42049 Konya (Turkey); Y?ld?z, Murat, E-mail: muraty70@gmail.com [Department of Physics, Faculty of Science, Karamanoglu Mehmetbey University, Karaman (Turkey)

2014-07-15

449

Nb3Sn quadrupoles in the LHC IR Phase I upgrade  

SciTech Connect

After a number of years of operation at nominal parameters, the LHC will be upgraded to a higher luminosity. This paper discusses the possibility of using a limited number of Nb{sub 3}Sn quadrupoles for hybrid optics layouts for the LHC Phase I luminosity upgrades with both NbTi and Nb{sub 3}Sn quadrupoles. Magnet parameters and issues related to using Nb{sub 3}Sn quadrupoles including aperture, gradient, magnetic length, field quality, operation margin, et cetera are discussed.

Zlobin, A.V.; Johnstone, J.A.; Kashikhin, V.V.; Mokhov, N.V.; Rakhno, I.L.; /Fermilab; de Maria, R.; Peggs, S.; Robert-Demolaize, G.; Wanderer, P.; /Brookhaven

2008-06-01

450

Nb3Sn Quadrupoles in the LHC IR Phase I Upgrade  

SciTech Connect

After a number of years of operation at nominal parameters, the LHC will be upgraded for higher luminosity. This paper discusses the possibility of using a limited number of Nb{sub 3}Sn quadrupoles for hybrid optics layouts for the LHC Phase I luminosity upgrades with both NbTi and Nb{sub 3}Sn quadrupoles. Magnet parameters and issues related to using Nb{sub 3}Sn quadrupoles including aperture, gradient, magnetic length, field quality, operation margin, et cetera are discussed.

Zlobin,A.; Johnstone, J.; Kashikhin, V.; Mokhov, N.; Rakhno, I.; deMaria, R.; Peggs, S.; Robert-Demolaize, F.; Wanderer, P.

2008-06-23

451

Metabolic profile of miltirone in rats by high performance liquid chromatography/quadrupole time-of-flight mass spectrometry.  

PubMed

Miltirone is one of the bioactive diterpene quinones isolated from Salvia miltiorrhiza Bunge. This compound has been found to possess significant anticancer, antibacterial, antioxidant, and anti-inflammatory activities. However, the metabolic fate of miltirone remains unknown. In order to explore whether miltirone is extensively metabolized, we investigated the metabolites of miltirone in plasma, bile, urine, and feces samples following oral and intravenous administration to the rats. By using high performance liquid chromatography/quadrupole time-of-flight mass spectrometry (HPLC/Q-TOF-MS) coupled with mass detect filter (MDF) method, a total of 15 metabolites were identified from the biosamples. Both phase I and phase II metabolites were observed in the metabolic profile and the metabolic pathways involved in reduction, oxidation, monohydroxylation, dihydroxylation, glucuronidation and sulfation. The results indicated that hepatocyte metabolism was the major route of clearance for the parent compound. The present study provided valuable information for better understanding of the efficacy and safety of miltirone. PMID:25679091

Guo, Long; Duan, Li; Dong, Xin; Dou, Li-Li; Zhou, Ping; Li, Ping; Liu, E-Hu

2015-03-25

452

Open Problems in Understanding the Nuclear Chirality  

E-print Network

Open problems in the interpretation of the observed pair of near degenerate $\\Delta I = 1$ bands with the same parity as the chiral doublet bands are discussed. The ambiguities for the existing fingerprints of the chirality in atomic nuclei and problems in existing theory are discussed, including the description of quantum tunneling in the mean field approximation as well as the deformation, core polarization and configuration of particle rotor model (PRM). Future developments of the theoretical approach are prospected.

Jie Meng; S. Q. Zhang

2010-02-04

453

Relations Involving Static Quadrupole Moments of $2^+$ states and B(E2)'s  

E-print Network

We define the ``quadrupole ratio'' $r_Q = \\dfrac{Q_0(S)}{Q_0(B)}$ where $Q_0(S)$ is the intrinsic quadrupole moment obtained from the static quadrupole moment of the $2_1^+$ state of an even-even nucleus and $Q_0(B)$ the intrinsic quadrupole moment obtained from $B(E2)_{0 \\to 2}$. In both cases we assume a simple rotational formula connecting the rotating frame to the laboratory frame. The quantity $r_Q$ would be one if the rotational model were perfect and the energy ratio $E(4)/E(2)$ would be 10/3. In the simple vibrational model, $r_Q$ would be zero and $E(4)/E(2)$ would be two. There are some regions where the rotational limit is almost met and fewer where the vibrational limit is also almost met. For most cases, however, it is between these two limits, i.e. $0 light nuclei.

Sean Yeager; Larry Zamick

2008-08-28

454

A modified quadrupole mass spectrometer with custom RF link rods driver for remote operation  

NASA Technical Reports Server (NTRS)

A commercial quadrupole residual gas analyzer system has been upgraded for operation at extended cable lengths. Operation inside a vacuum chamber for the standard quadrupole nude head is limited to approximately 2 m from its externally located rf/dc generator because of the detuning of the rf oscillator circuits by the coaxial cable reactance. The advance of long distance remote operation inside a vacuum chamber for distances of 45 and 60 m was made possible without altering the quadrupole's rf/dc generator circuit by employing an rf link to drive the quadrupole rods. Applications of the system have been accomplished for in situ space simulation thermal/vacuum testing of sophisticated payloads.

Tashbar, P. W.; Nisen, D. B.; Moore, W. W., Jr.

1973-01-01

455

High-performance MEMS square electrode quadrupole mass filters for chip-scale mass spectrometry  

E-print Network

We report exciting experimental data from a low-cost, high-performance square electrode quadrupole mass filter with integrated ion optics intended for chips-cale mass spectrometry. The device showed a mass range of 650 amu ...

Cheung, Kerry

456

A compact beam focusing and steering element using quadrupoles with independently excited poles  

NASA Astrophysics Data System (ADS)

Beam steering elements for accelerator beam transport are conventionally and conveniently incorporated into beamlines by fitting magnetic dipole elements around the vacuum tube of the line. Two steerers in each plane (X and Y) together with a quadrupole doublet constitute a module providing full control of the direction, position and focus of the beam. In some installations however, there may be insufficient space on the beamline to mount separate steerer elements. To provide steering capabilities in such a situation we have used a magnetic quadrupole doublet with the coils of each pole independently excited to synthesise the desired combination of quadrupole, horizontal dipole and vertical dipole fields. This paper describes the quadrupole steerer and its multichannel power supply and presents calculated magnetic field distributions together with raytracing simulation of its performance.

Grime, Geoffrey W.

2013-07-01

457

Photoionization of Ca 4s in a spherical attractive well potential: dipole, quadrupole and relativistic effects  

NASA Astrophysics Data System (ADS)

A study of the outer 4s subshell of the Ca atom in a spherical attractive potential well (SAW) of variable depth is performed to determine the effect of an external potential on dipole (E1) and quadrupole (E2) photoionization processes. As the depth of the potential well increases, dramatic changes are observed in the 4s cross-section, as well as in the photoelectron angular distribution. The existence of Cooper minima in the 4s dipole channels give rise to very significant effects of quadrupole interactions, even at extremely low energies, in the vicinity of the E1 Cooper minimum. It is shown that the entrapment of Ca in a spherical attractive well (Ca@SAW) further enhances the importance of quadrupole interactions determining the photoionization parameters. The complicated behavior of both dipole and quadrupole Cooper minima, as functions of well depth, is delineated, along with the importance of relativistic effects.

Kumar, Ashish; Varma, Hari R.; Pradhan, Gagan B.; Deshmukh, Pranawa C.; Manson, Steven T.

2014-09-01

458

Design and operation of a laminar-flow electrostatic-quadrupole-focused acceleration column  

SciTech Connect

This report deals with the design principles involved in the design of a laminar-flow electrostatic-quadrupole-focused acceleration column. In particular, attention will be paid to making the parameters suitable for incorporation into a DC MEQALAC design.

Maschke, A.W.

1983-06-20

459

Extended bodies in a Kerr spacetime: exploring the role of a general quadrupole tensor  

E-print Network

The equatorial motion of extended bodies in a Kerr spacetime is investigated in the framework of the Mathisson-Papapetrou-Dixon model, including the full set of effective components of the quadrupole tensor. The numerical integration of the associated equations shows the specific role of the mass and current quadrupole moment components. While most of the literature on this topic is limited to spin-induced (purely electric) quadrupole tensor, the present analysis highlights the effect of a completely general quadrupole tensor on the dynamics. The contribution of the magnetic-type components is indeed related to a number of interesting features, e.g., enhanced inward/outward spiraling behavior of the orbit and spin-flip-like effects, which may have observational counterparts. Finally, the validity limit of the Mathisson-Papapetrou-Dixon model is also discussed through explicit examples.

Donato Bini; Andrea Geralico

2014-08-23

460

Field Quality Measurements and Analysis of the LARP Technology Quadrupole Models  

SciTech Connect

One of the US-LHC accelerator research program goals is to develop and prove the design and technology of Nb{sub 3}Sn quadrupoles for an upgrade of the LHC Interaction Region (IR) inner triplets. Four 1-m long technology quadrupole models with a 90 mm bore and field gradient of 200 T/m based on similar coils and different mechanical structures have been developed. In this paper, we present the field quality measurements of the first several models performed at room temperature as well as at superfluid helium temperature in a wide field range. The measured field harmonics are compared to the calculated ones. The field quality of Nb{sub 3}Sn quadrupole models is compared with the NbTi quadrupoles recently produced at Fermilab for the first generation LHC IRs.

Chlachidze, G.; DiMarco, J.; Kashikhin, V.V.; Lamm, M.; Schlabach, P.; Tartaglia, M.; Tompkins, J.C.; Velev, G.V.; Zlobin, A.V.; Caspi, S.; Ferracin, P.; Sabbi, G.I.; Bossert, R.

2008-06-01

461

Field quality measurements and abalysis of the LARP technology quadrupole models  

SciTech Connect

One of the US-LHC accelerator research program goals is to develop and prove the design and technology of Nb{sub 3}Sn quadrupoles for an upgrade of the LHC Interaction Region (IR) inner triplets. Four 1-m long technology quadrupole models with a 90 mm bore and field gradient of 200 T/m based on similar coils and different mechanical structures have been developed. In this paper, we present the field quality measurements of the first several models performed at room temperature as well as at superfluid helium temperature in a wide field range. The measured field harmonics are compared to the calculated ones. The field quality of Nb{sub 3}Sn quadrupole models is compared with the NbTi quadrupoles recently produced at Fermilab for the first generation LHC IRs.

Bossert, R.; Chlachidze, G.; DiMarco, J.; Kashikhin, V.V.; Lamm, M.; Schlabach, P.; Tartaglia, M.; Tompkins, J.C.; Velev, G.V.; Zlobin, A.V.; Caspi, S.; /Fermilab /LBL, Berkeley

2007-08-01

462

Tandem quadrupole Fourier-transform mass spectrometry of oligopeptides and small proteins.  

PubMed Central

Modifications to the newly developed tandem quadrupole Fourier-transform mass spectrometer have made it possible to record mass spectra on oligopeptides and small proteins in the mass range between 2 and 13 kDa. PMID:3468502

Hunt, D F; Shabanowitz, J; Yates, J R; Zhu, N Z; Russell, D H; Castro, M E

1987-01-01

463

Rotational and magnetic shunt permanent magnet quadrupoles with variable magnetic strength  

SciTech Connect

Next Linear Collider (NLC) and Very Large Hadron Collider (VLHC) projects suppose to use permanent magnets as bending, focusing and correcting elements. Prototypes of two permanent magnet quadrupoles with variable strength were built and successfully tested in Fermilab. Quadrupoles have 12.7 mm aperture diameter, 100 T/m gradient with an adjustment range of 0 to -20%. Special designs provide high precision magnetic center stability during strength change. SmCo5 permanent magnet bricks were used in these prototypes. Rotational quadrupole consists of four sections. Two central sections are rotated in counter directions to adjust the strength. Magnetic shunt quadrupole design provides variable shunting of the magnetic flux. The numerical simulation, designs, measuring results are described.

Vladimir Kashikhin et al.

2002-03-28

464

Single-crystal EPR, 35,37Cl and 14,15N ENDOR and ESEEM studies on (Ph 4As)[Tc VINCl 4/Tc VOCl 4]. II. Determination of the 35,37Cl and 14,15N hyperfine and quadrupole tensors by ENDOR and ESEEM  

NASA Astrophysics Data System (ADS)

Single-crystal ENDOR and ESEEM studies on 35,37Cl and 14,15N nuclei are reported for the 4d 1 ( S= 1/2) complex (Ph 4As) [TcNCl 4], a spin system consisting of four 35Cl and four 37Cl nuclei ( I= 3/2), and one 14N ( 15N) nucleus with I = 1 ( I = 1/2), respectively ( I( 99Tc) = 9/2). The 35,37Cl spectra are characterized by different ratios of the hyperfine, nuclear Zeeman and the nuclear quadrupole interaction depending on the B0 field orientation: HQ < Hhf+ HNZ, and HQ t˜ Hhf+ HNZ and HQ? Hhf+ HNZ. A general description of this situation is given and the characteristics of ENDOR and ESEEM are discussed. The 14N spectra are also strongly influenced by nuclear quadrupole interaction; the isotropic 14N ( 15N) coupling is unexpectedly large. Molecular orbital calculations (EHMO and NDDO) are made to account for the hyperfine parameters and indicate that the 14,15N coupling is mainly determined by spin polarization. The hyperfine and nuclear quadrupole couplings are used to discuss the actual symmetry and the bonding situation of the incorporated TcNCl 4- anion. For the interpretation of the quadrupole data the Townes-Dailey model has been used.

Köhler, K.; Kirmse, R.; Böttcher, R.; Abram, U.; Gribnau, M. C. M.; Keijzers, C. P.; De Boer, E.

1990-05-01

465

Set Up and Test Results for a Vibrating Wire System for Quadrupole Fiducialization  

SciTech Connect

Quadrupoles will be placed between the undulator segments in LCLS to keep the electron beam focused as it passes through. The quadrupoles will be assembled with their respective undulator segments prior to being placed into the tunnel. Beam alignment will be used to center the quadrupoles, along with the corresponding undulators, on the beam. If there is any displacement between the undulator and the quadrupole axes in the assemblies, the beam will deviate from the undulator axis. If it deviates by more than 80{micro}m in vertical or 140{micro}m in horizontal directions, the undulator will not perform as required by LCLS. This error is divided between three sources: undulator axis fiducialization, quadrupole magnetic axis fiducialization, and assembly of the two parts. In particular, it was calculated that the quadrupole needs to be fiducialized to within 25{micro}m in both vertical and horizontal directions. A previous study suggested using a vibrating wire system for finding the magnetic axis of a quadrupole. The study showed that the method has high sensitivity (up to 1{micro}m) and laid out guidelines for constructing it. There are 3 steps in fiducializing the quadrupole with the vibrating wire system. They are positioning the wire at the magnet center (step 1), finding the wire with position detectors (step 2), and finding the quadrupole tooling ball positions relative to the position detector tooling balls (step 3). The following break up of error was suggested for the fiducialization steps: 10{micro}m for step 1 (finding the center), 20{micro}m for step 2 (finding the wire), and 10{micro}m for step 3 (tooling ball measurements). The purpose of this study is to investigate whether the vibrating wire system meets the requirements for LCLS. In particular, if it can reliably fiducialize a quadrupole magnetic center to within 25{micro}m in both vertical and horizontal directions. The behavior of individual system components is compared to the expected performance. A vibrating wire system was constructed to fiducialize the quadrupoles between undulator segments in the LCLS. This note studies the ability of the system to fulfill the fiducialization requirements.

Not Available

2010-11-29

466

Set Up and Test Results for a Vibrating Wire System for Quadrupole Fiducialization  

SciTech Connect

Quadrupoles will be placed between the undulator segments in LCLS to keep the electron beam focused as it passes through. The quadrupoles will be assembled with their respective undulator segments prior to being placed into the tunnel. Beam alignment will be used to center the quadrupoles, along with the corresponding undulators, on the beam. If there is any displacement between the undulator and the quadrupole axes in the assemblies, the beam will deviate from the undulator axis. If it deviates by more than 80{micro}m in vertical or 140{micro}m in horizontal directions, the undulator will not perform as required by LCLS. This error is divided between three sources: undulator axis fiducialization, quadrupole magnetic axis fiducialization, and assembly of the two parts. In particular, it was calculated that the quadrupole needs to be fiducialized to within 25{micro}m in both vertical and horizontal directions. A previous study suggested using a vibrating wire system for finding the magnetic axis of a quadrupole. The study showed that the method has high sensitivity (up to 1{micro}m) and laid out guidelines for constructing it. There are 3 steps in fiducializing the quadrupole with the vibrating wire system. They are positioning the wire at the magnet center (step 1), finding the wire with position detectors (step 2), and finding the quadrupole tooling ball positions relative to the position detector tooling balls (step 3). The following break up of error was suggested for the fiducialization steps: 10{micro}m for step 1 (finding the center), 20{micro}m for step 2 (finding the wire), and 10{micro}m for step 3 (tooling ball measurements). The purpose of this study is to investigate whether the vibrating wire system meets the requirements for LCLS. In particular, if it can reliably fiducialize a quadrupole magnetic center to within 25{micro}m in both vertical and horizontal directions. The behavior of individual system components is compared to the expected performance. A vibrating wire system was constructed to fiducialize the quadrupoles between undulator segments in the LCLS. This note studies the ability of the system to fulfill the fiducialization requirements.

Levashov, Michael Y.

2010-12-01

467

Development of TQC01, a 90 mm Model Quadrupole for LHC Upgrade Based on SS Collar  

Microsoft Academic Search

As a first step toward the development of a large-aperture Nb3Sn superconducting quadrupole for the Large Hadron Collider (LHC) luminosity upgrade, two-layer technological quadrupole models (TQS01 at LBNL and TQC01 at Fermilab) are being constructed within the framework of the US LHC Accelerator Research Program (LARP). Both models use the same coil design, but have different coil support structures. This

R. C. Bossert; G. Ambrosio; N. Andreev; E. Barzi; S. Caspi; D. R. Dietderich; P. Ferracin; A. Ghosh; S. A. Gourlay; A. R. Hafalia; C. R. Hannaford; V. S. Kashikhin; V. V. Kashikhin; A. F. Lietzke; S. Mattafirri; A. D. McInturff; I. Novitski; G. L. Sabbi; D. Turrioni; G. Whitson; R. Yamada; A. V. Zlobin

2006-01-01

468

Field quality in Fermilab-built models of quadrupole magnets for the LHC interaction region  

Microsoft Academic Search

Superconducting quadrupole magnets for the interaction regions of the Large Hadron Collider are being developed by the US-LHC Accelerator Project. These 70 mm bore quadrupole magnets are intended to operate in superfluid helium at 1.9 K with a nominal field gradient of 215 T\\/m. A series of 2 m model magnets has been built and cold tested at Fermilab to

N. Andreev; T. Arkan; P. Bauer; R. Bossert; J. Brandt; S. Caspi; D. R. Chichili; J. Carson; J. DiMarco; S. Feher; A. Ghosh; H. Glass; V. V. Kashikhin; J. Kerby; M. J. Lamm; A. D. McInturff; A. A. Makarov; A. Nobrega; I. Novitski; T. Ogitsu; D. Orris; J. P. Ozelis; T. Peterson; R. Rabehl; W. Robotham; G. Sabbi; R. Scanlan; P. Schlabach; C. Sylvester; J. Strait; M. Tartaglia; J. C. Tompkins; G. Velev; S. Yadav; A. V. Zlobin

2001-01-01

469

Global investigation of the fine structure of the isoscalar giant quadrupole resonance  

Microsoft Academic Search

Fine structure in the region of the isoscalar giant quadrupole resonance (ISGQR) in Ni, Y, °Zr, ¹²°Sn, ¹Er, and ²°Pb has been observed in high-energy-resolution (E35-50 keV) inelastic proton scattering measurements at E=200 MeV at iThemba LABS. Calculations of the corresponding quadrupole excitation strength functions performed within models based on the random-phase approximation (RPA) reveal similar fine structure when the

A. Shevchenko; O. Burda; Y. Kalmykov; P. von Neumann-Cosel; V. Yu. Ponomarev; A. Richter; J. Wambach; J. Carter; E. Sideras-Haddad; G. R. J. Cooper; R. W. Fearick; S. V. Foertsch; J. J. Lawrie; R. Neveling; F. D. Smit; H. Fujita; Y. Fujita; D. Lacroix

2009-01-01

470

Permanent Magnet Skew Quadrupoles for the Low Emittance LER Lattice of PEP-II  

SciTech Connect

The vertical emittance of the low energy ring (LER) in the PEP-II B-Factory was reduced by using skew quadrupoles consisting of permanent magnet material. The advantages over electric quadrupoles or rotating existing normal quadrupoles are discussed. To assure a high field quality, a Biot-Savart calculation was used to cancel the natural 12-pole component by using different size poles over a few layers. A magnetic measurement confirmed the high quality of the magnets. After installation and adjusting the original electric 12 skew and 16 normal quadrupoles the emittance contribution from the region close to the interaction point, which was the biggest part in the original design, was considerably reduced. To strengthen the vertical behavior of the LER beam, a low emittance lattice was developed. It lowered the original vertical design emittance from 0.54 nm-rad to 0.034 nm-rad. In order to achieve this, additional skew quadrupoles were required to bring the coupling correction out of the arcs and closer to the detector solenoid in the straight (Fig. 1). It is important, together with low vertical dispersion, that the low vertical emittance is not coupled into the horizontal, which is what we get if the coupling correction continues into the arcs. Further details of the lattice work is described in another paper; here we concentrate on the development of the permanent skew (PSK) quadrupole solution. Besides the permanent magnets there are two other possibilities, using electric magnets or rotating normal quadrupoles. Electric magnets would have required much more additional equipment like magnets stands, power supply, and new vacuum chamber sections. Rotating existing quadrupoles was also not feasible since they are mostly mounted together with a bending magnet on the same support girder.

Decker, F.-J.; Anderson, S.; Kharakh, D.; Sullivan, M.; /SLAC

2011-07-05

471

Performance of Nb3Sn quadrupole magnets under localized thermal load  

SciTech Connect

This paper describes the results of design and analyses performed on 120-mm Nb{sub 3}Sn and NbTi quadrupole magnets with parameters relevant for the LHC IR upgrade. A realistic radiation heat load is evaluated in a wide luminosity range and translated into the magnet quench performance. The simulation results are supported by thermal measurements on a 90-mm Nb{sub 3}Sn quadrupole coil.

Kashikhin, V.V.; Bossert, r.; Chlachidze, G.; Lamm, M.; Mokhov, N.V.; Novitski, I.; Zlobin, A.V.; /Fermilab

2009-06-01

472

Bose-Einstein condensation in a quadrupole-Ioffe-configuration trap  

Microsoft Academic Search

We demonstrate Bose-Einstein condensation of rubidium atoms in a simple low-power magnetic trap. This trap combines the quadrupole with the Ioffe configuration (QUIC trap) and consists of just three coils. Magneto-optically trapped 87Rb atoms are first loaded into the linear trapping potential of a magnetic quadrupole, which is then converted into the parabolic geometry of an Ioffe trap. During this

Tilman Esslinger; Immanuel Bloch; Theodor W. Hänsch

1998-01-01

473

Progress in the Long ${\\\\rm Nb}_{3}{\\\\rm Sn}$ Quadrupole R&D by LARP  

Microsoft Academic Search

After the successful test of the first long ${\\\\rm Nb}_{3}{\\\\rm Sn}$ quadrupole (LQS01) the US LHC Accelerator Research Program (LARP, a collaboration of BNL, FNAL, LBNL and SLAC) is assessing training memory, reproducibility, and other accelerator quality features of long ${\\\\rm Nb}_{3}{\\\\rm Sn}$ quadrupole magnets. LQS01b (a reassembly of LQS01 with more uniform and higher pre-stress) was subjected to a

G. Ambrosio; N. Andreev; M. Anerella; E. Barzi; D. Bocian; R. Bossert; M. Buehler; S. Caspi; G. Chlachidze; D. Dietderich; J. DiMarco; J. Escallier; H. Felice; P. Ferracin; A. Ghosh; A. Godeke; R. Hafalia; R. Hannaford; G. Jochen; M. J. Kim; P. Kovach; M. Lamm; M. Marchevsky; J. Muratore; F. Nobrega; D. Orris; E. Prebys; S. Prestemon; G. L. Sabbi; J. Schmalzle; C. Sylvester; M. Tartaglia; D. Turrioni; G. Velev; P. Wanderer; G. Whitson; A. V. Zlobin

2012-01-01

474

Electric Quadrupole Moments of the Decuplet and the Strangeness Content of the Proton  

E-print Network

In the SU3 Skyrme model the electric quadrupole moments of $\\frac{3}{2}^+$ baryons show a strong sensitivity with respect to flavor distortions in baryon wavefunctions. SU3 symmetric wavefunctions lead to quadrupole moments proportional to the charge of the baryon whereas for strongly broken flavor symmetry a proportionality to baryonic isospin emerges. Since the flavor distortions in the wavefunctions also determine the strangeness content of the proton the Skyrme model provides a link between both quantities.

J. Kroll; B. Schwesinger

1994-05-11

475

Laser cooling and sympathetic cooling in a linear quadrupole rf trap  

E-print Network

LASER COOLING AND SYMPATHETIC COOLING IN A LINEAR QUADRUPOLE RF TRAP A Dissertation by VLADIMIR LEONIDOVICH RYJKOV Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree... of DOCTOR OF PHILOSOPHY December 2003 Major Subject: Physics LASER COOLING AND SYMPATHETIC COOLING IN A LINEAR QUADRUPOLE RF TRAP A Dissertation by VLADIMIR LEONIDOVICH RYJKOV Submitted to Texas A&M University in partial fulfillment of the requirements...

Ryjkov, Vladimir Leonidovich

2005-02-17

476

Fabrication and test of LARP technological quadrupole models of TQC series  

Microsoft Academic Search

In support of the development of a large-aperture Nb3Sn superconducting quadrupole for the Large Hadron Collider (LHC) luminosity upgrade, several two-layer technological quadrupole models of TQC series with 90 mm aperture and collar-based mechanical structure have been developed at Fermilab in collaboration with LBNL. This paper summarizes the results of fabrication and test of TQC02a, the second TQC model based

R. C. Bossert; G. Ambrosio; N. Andreev; E. Barzi; G. Chlachidze; S. Feher; V. S. Kashikhin; V. V. Kashikhin; M. Lamm; A. Nobrega; I. Novitski

2008-01-01

477

Test Results of LARP Quadrupole Magnets Using a Shell-Based Support Structure (TQS)  

Microsoft Academic Search

Amongst the magnet development program of a large-aperture Nb3Sn superconducting quadrupole for the Large Hadron Collider luminosity upgrade, six quadrupole magnets were built and tested using a shell based key and bladder technology (TQS). The 1 m long 90 mm aperture magnets are part of the US LHC Accelerator Research Program (LARP) aimed at demonstrating Nb3Sn technology by the year

Shlomo Caspi; Daniel R. Dietderich; Helene Felice; Paolo Ferracin; R. Hafalia; C. R. Hannaford; A. F. Lietzke; Juan Lizarazo; GianLuca Sabbi; X. R. Wang; Arup Ghosh; Peter Wanderer; Giorgio Ambrosio; Emanuela Barzi; Rodger Bossert; Guram Chlachidze; Sandor Feher; Vadim V. Kashikhin; Michael Lamm; Michael A. Tartaglia; Alexander V. Zlobin; Marta Bajko; Bernardo Bordini; Gijs DeRijk; Christian Giloux; Mikko Karppinen; Juan C. Perez; Lucio Rossi; Andrzej Siemko; Ezio Todesco

2009-01-01

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