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1

Understanding nuclear quadrupole deformations  

SciTech Connect

A simple ansatz that ''Nuclei, not too near closed shells, are as deformed as they can be within a single major shell'' appears to quantitatively reproduce the variations of the quadrupole moments and hence the deformations of nuclei. 6 refs., 3 figs.

Raman, S.

1989-01-01

2

Temperature Variation of Nuclear Quadrupole Resonance Frequencies  

Microsoft Academic Search

A superregenerative nuclear quadrupole resonance spectrometer designed for use in an advanced undergraduate laboratory is described. The temperature variations of the 63Cu and 65Cu resonances in Cu2O are investigated. The results yield information on the lattice dynamics of Cu2O and allow a determination of the ratio of the nuclear quadrupole moments of the copper isotopes.

G. L. Baker; R. L. Armstrong

1968-01-01

3

Nuclear quadrupole resonance of norephedrine.  

PubMed

Toward searching for illegal drugs, we investigated the pulsed nuclear quadrupole resonance (NQR) response of 14N in (1R,2S)-(-)-norephedrine, based on the predictions of quantum chemical calculations. Two pairs of spectral lines (?+=3.089, 3.093 MHz and ?-=2.594, 2.608 MHz) were observed despite its molecule structure having only a single nitrogen atom. This indicates that the molecular crystal has two nonequivalent nitrogen atoms in the unit cell. The temperature dependence of the NQR frequencies and relaxation properties were investigated for the purpose of accurate remote sensing of the drugs. The NQR frequency shift was approximately 0.23 kHz/K around room temperature. The spin-lattice relaxation and spin-phase memory times were 5.2-10.2 ms and 0.6-1.5 ms, respectively. PMID:21924876

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

2011-09-06

4

Nuclear quadrupole moment of {sup 201}Hg  

SciTech Connect

The multiconfiguration Dirac-Hartree-Fock model has been employed to compute the magnetic dipole hyperfine structure constant and the electric field gradient in the {sup 3}P{sub 1} state of neutral mercury. Combined with the experimental electric quadrupole hyperfine interaction constant, the computed electric field gradient yields the nuclear quadrupole moment Q=387{+-}6 mb for {sup 201}Hg. This value is in good agreement with older muonic, atomic, and solid-state values, but differs from the latest muonic result and from the recent {gamma} spectroscopy determination.

Bieron, Jacek [Instytut Fizyki imienia Mariana Smoluchowskiego, Uniwersytet Jagiellonski, Reymonta 4, PL-30-059 Cracow (Poland); Pyykkoe, Pekka [Department of Chemistry, University of Helsinki, P.O. Box 55 (A.I. Virtasen aukio 1), 00014 Helsinki (Finland); Joensson, Per [Applied Mathematics Group, Malmoe University, 205 06 Malmoe (Sweden)

2005-01-01

5

Nuclear quadrupole resonance single-pulse echoes.  

PubMed

We report the first detection of a spin echo after excitation of a powder sample by a single pulse at the resonance frequency during nuclear quadrupole resonance (NQR). These echoes can occur in samples that have an inhomogeneously broadened line, in this case due to the distribution of electric field gradients. The echoes are easily detectable when the Rabi frequency approaches the linewidth and the average effective tipping angle is close to 270 degrees. When limited by a weak radio-frequency field, the single-pulse echo can be used to increase the signal to noise ratio over conventional techniques. These effects can be used to optimize the NQR detection of contraband containing quadrupole nuclei and they are demonstrated with glycine hemihydrochloride and hexhydro-1,3,5-trinitro-1,3,5-triazine (RDX). PMID:18571445

Prescott, David W; Miller, Joel B; Tourigny, Chris; Sauer, Karen L

2008-05-29

6

Land mine detection by nuclear quadrupole resonance  

NASA Astrophysics Data System (ADS)

Nuclear Quadrupole Resonance (NQR) combines the compound specific detection capability offered by chemical detection techniques with the spatial localization capability and convenience of an induction coil metal detector. In the 16 years since NQR was last applied to mine detection in the U.S., there has been considerable improvement in the basic techniques. This paper reviews the progress achieved under a recent initiative to detect landmines by NQR. Two basic technical developments are summarized: the design of a detection coil suitable for probing the ground for landmines buried at typical depths, and an increase in the NQR signal obtained from the explosive TNT. In addition, we report the sensitivity of an NQR detection system to detect the electromagnetic response of metal-cased landmines.

Hibbs, Andrew D.; Barrall, Geoffrey A.; Czipott, Peter V.; Lathrop, Daniel K.; Lee, Y. K.; Magnuson, Erik E.; Matthews, Robert; Vierkoetter, S. A.

1998-09-01

7

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, M. L.; Yesinowski, J. P.; Miller, J. B.; Krauss, Ronald A.

1994-10-01

8

On the signs of nuclear quadrupole moments  

Microsoft Academic Search

We analyse the experimental data on the signs of all the measured quadrupole moments in the ground states of nuclei. We find positive quadrupole moments in virtually all the cases where the last major proton and neutron shells are both more than one-fifth full. For odd-mass nuclei the quadrupole moment is negative (positive) when the odd nucleons occupy 1\\/8 or

Yitzhak Y. Sharon

1967-01-01

9

Nuclear Quadrupole Resonance in Hexamethylenetetramine: Modulation and Reorientational Broadening  

Microsoft Academic Search

The temperature dependences of the frequency and linewidth of the nuclear quadrupole resonance absorption in hexamethylenetetramine have been measured in the range between 297–380°K using a Zeeman modulated spectrometer. The results are reported and interpreted both in terms of the molecular reorientation that is known to take place at these temperatures and the modulation broadening expected from this type of

S. Eletr

1970-01-01

10

14N nuclear quadrupole resonance in carcinostatic phosphamides  

NASA Astrophysics Data System (ADS)

Nitrogen-14 nuclear quadrupole resonance spectra of the anti-cancer drugs cyclophosphamide monohydrate, isonphosphamide and triphosphamide have been detected at 77 K. The electron distribution in the vicinity of the nitrogens possessing trigonal bonding configurations have been calculated in the framework of the Townes and Dailey theory.

Greenbaum, S. G.; Bray, P. J.

1980-02-01

11

Nuclear quadrupole coupling interactions in the rotational spectrum of tryptamine  

NASA Astrophysics Data System (ADS)

Four conformers of tryptamine have been detected in a supersonic expansion and characterized by laser ablation molecular beam Fourier transform microwave spectroscopy LA-MB-FTMW in the 5-10 GHz frequency range. The quadrupole hyperfine structure originated by two 14N nuclei has been completely resolved for all conformers and used for their unambiguous identification. Nuclear quadrupole coupling constants of the nitrogen atom of the side chain have been used to determine the orientation of the amino group involved in N-H\\ctdot ? interactions: to the ? electronic system of the pyrrole unit in the Gauche-Pyrrole conformers (GPy) or to the phenyl unit in the Gauche-Phenyl ones.

Alonso, J. L.; Cortijo, V.; Mata, S.; Pérez, C.; Cabezas, C.; López, J. C.; Caminati, W.

2011-09-01

12

Detection of ammonium nitrate inside vehicles by nuclear quadrupole resonance  

Microsoft Academic Search

The development of a system for the detection of ammonium nitrate (AN) in vehicles by nuclear quadrupole resonance (NQR) is\\u000a described. The results from studies of the penetration of radiofrequency (RF) magnetic fields inside certain metal enclosures,\\u000a including full-scale vehicles, were critical in the design of a novel high-Q resonant probe. The probe was shaped not only for optimal penetration

J. Barras; M. J. Gaskell; N. Hunt; R. I. Jenkinson; K. R. Mann; D. A. G. Pedder; G. N. Shilstone; J. A. S. Smith

2004-01-01

13

Detection of ammonium nitrate inside vehicles by Nuclear Quadrupole Resonance  

Microsoft Academic Search

\\u000a Nuclear quadrupole resonance (NQR) has been demonstrated for the detection of explosives in a number of potential applications,\\u000a including baggage screening, mail screening and landmine detection. A further highly desirable application concerns the detection\\u000a of explosives concealed within a vehicle, which from the point of view of RF penetration can be considered as a large metal\\u000a box with holes in

J. Barras; M. J. Gaskell; N. Hunt; R. I. Jenkinson; K. Mann; D. Peddar; G. N. Shilstone; J. A. S. Smith

14

Feasibility of nuclear quadrupole resonance as a novel dosimetry tool  

Microsoft Academic Search

Nuclear quadrupole resonance (N.Q.R) frequencies are influenced by the symmetry of the charge distribution of a compound around the site of interest. Damage by ionizing radiation causes changes in this charge symmetry which can be detected by standard pulsed N.Q.R. methods. Previous work done on various chlorates of [sup 35]Cl at room temperature (Vargas et al., 1978) shows a linear

L. H. Iselin; D. E. Hintenlang; S. J. Epperson; G. A. Higgins; K. Jamil

1990-01-01

15

Feasibility of nuclear quadrupole resonance as a novel dosimetry tool  

Microsoft Academic Search

Nuclear quadrupole resonance (N.Q.R) frequencies are influenced by the symmetry of the charge distribution of a compound around the site of interest. Damage by ionizing radiation causes changes in this charge symmetry which can be detected by standard pulsed N.Q.R. methods. Previous work done on various chlorates of ³⁵Cl at room temperature (Vargas et al., 1978) shows a linear effect

L. H. Iselin; D. E. Hintenlang; S. J. Epperson; G. A. Higgins; K. Jamil

1990-01-01

16

Ressonancia de quadrupolo nuclear da arsenolita. (Nuclear quadrupole resonance of arsenolite).  

National Technical Information Service (NTIS)

A pulsed Nuclear Quadrupole Resonance (NQR) spectrometer was constructed using imported Matec units. Peripherical components were specially assembled and tested for the implantation of the spin-echo technique in the Laboratorio de Centros de Cor of IFUSP....

R. Madarazo

1988-01-01

17

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

18

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

19

Nuclear quadrupole resonance study of hydrogen bonded solid materials.  

PubMed

Nuclear quadrupole resonance is presented as a method for the study of solid hydrogen bonded materials. NQR study of hydrogen bonds in ferroelectric and paraelectric KH2PO4, antiferroelectric and paraelectric squaric acid, ferroelectric croconic acid and antiferroelectric and paraelectric cocrystal 5'-dimethyl-2, 2'-bipyridine - chloranilic acid (1:1) are discussed in more details. A 14N NQR study of the strong short O-HKN hydrogen bond in two polymorphic forms of cocrystal isonicotinamide-oxalic acid (2:1) is presented as well. Various correlations between the NQR parameters and between the NQR and structural parameters have been observed. These correlations may be used to determine the proton position in a hydrogen bond and some other structural parameters from the NQR data. PMID:24062106

Seliger, Janez

2011-09-01

20

A versatile computer-controlled pulsed nuclear quadrupole resonance spectrometer  

NASA Astrophysics Data System (ADS)

A new, pulsed nuclear quadrupole resonance (NQR) spectrometer capable of performing a variety of pulsed and swept experiments is described. The spectrometer features phase locked, superheterodyne detection using a commercial spectrum analyzer and a fully automatic, computer-controlled tuning and matching network. The tuning and matching network employs stepper motors which turn high power air gap capacitors in a ``moving grid'' optimization strategy to minimize the reflected power from a directional coupler. In the duplexer circuit, digitally controlled relays are used to switch different lengths of coax cable appropriate for the different radio frequencies. A home-built pulse programmer card controls the timing of radio frequency pulses sent to the probe, while data acquisition and control software is written in Microsoft Quick Basic. Spin-echo acquisition experiments are typically used to acquire the data, although a variety of pulse sequences can be employed. Scan times range from one to several hours depending upon the step resolution and the spectral range required for each experiment. Pure NQR spectra of NaNO2 and 3-aminopyridine are discussed.

Fisher, Gregory; Macnamara, Ernesto; Santini, Robert E.; Raftery, Daniel

1999-12-01

21

The Common Chlorine Nuclear Electric Quadrupole Coupling Tensor for Acyl Chlorides  

NASA Astrophysics Data System (ADS)

We have determined the complete 35Cl and 37Cl nuclear electric quadrupole coupling tensors for two conformers of valeroyl chloride, CH_3-(CH_2)_3-COCl, using pure rotational spectroscopy. These tensors have been diagonalized into the principal axes and compared with chlorine principal quadrupole coupling tensors for a number of simple acyl chlorides. In general the components of the chlorine principal quadrupole coupling tensor, and in particular ?zz, are invariant to the organic group attached to the acyl chloride. It is evident, and not surprising, that the carbonyl of the acyl chloride functional group dominates the electric field gradient at the chlorine nucleus. We have found a common, acyl chloride functional group, 35Cl ?zz value of -59 ± 1 MHz. These findings will be discussed along with other work on tabulating common principal nuclear electric quadrupole coupling constants for relevant nuclei in simple organic functional groups. This work supported by IUPAC, Project No. 2010-048-3-100.

Powoski, R. A.; Cooke, S. A.

2012-06-01

22

Quadrupole collective inertia in nuclear fission: Cranking approximation  

NASA Astrophysics Data System (ADS)

A collective mass tensor derived from the cranking approximation to the adiabatic time-dependent Hartree-Fock-Bogoliubov (ATDHFB) approach is compared with that obtained in the Gaussian overlap approximation (GOA) to the generator coordinate method. Illustrative calculations are carried out for one-dimensional quadrupole fission pathways in 256Fm. It is shown that the collective mass exhibits strong variations with the quadrupole collective coordinate. These variations are related to the changes in the intrinsic shell structure. The differences between collective inertia obtained in cranking and perturbative cranking approximations to ATDHFB, and within GOA, are discussed.

Baran, A.; Sheikh, J. A.; Dobaczewski, J.; Nazarewicz, W.; Staszczak, A.

2011-11-01

23

Nuclear quadrupole structure of potassium hydroxide in the 32 GHz microwave region  

SciTech Connect

A high temperature Stark and radiofrequency-microwave double resonance spectrometer was used to observe the nuclear quadrupole structure of the J = 2reverse arrow1 transition of TZKOH in a number of vibrational states. First order analysis of the hyperfine components gave nuclear quadrupole coupling constants of eQq = -7.23 (29) MHz for the (000) state, eQq = -7.16 (33) MHz for the (100) state, and eQq = -7.29 (37) MHz for the (01 0) state.

Raw, T.T.; Yamamura, T.; Gillies, C.W.

1987-09-15

24

14N nuclear quadrupole resonance of picolinic, nicotinic, isonicotinic and dinicotinic acids  

NASA Astrophysics Data System (ADS)

The 14N nuclear quadrupole resonance (NQR) quadrupole coupling tensors of picolinic, nicotinic, isonicotinic and dinicotinic acids have been determined. Two different 14N quadrupole coupling constants 1007 kHz and 4159 kHz have been observed for picolinic acid demonstrating the presence of both protonated and non-protonated nitrogen atoms in this system in the solid. Only one set of non-protonated 14N NQR lines has been observed in other pyridinecarboxylic acids demonstrating the absence of the protonated zwitter ion forms observed in picolinic acid. The non-protonated 14N quadrupole coupling constant is the highest for the non-protonated nitrogen in picolinic acid and decreases to 3774 kHz in nicotinic acid and 3570 kHz in isonicotinic acid. It is the lowest in dinicotinic acid where the corresponding 14N quadrupole coupling constant is 2794 kHz. The observed anomalous decrease in the 14N quadrupole coupling constant of dinicotinic acid with decreasing temperature is tentatively explained as reflecting the increase in the residence time of the N-H⋯O bonded proton in the potential well close to the nitrogen.

Seliger, J.; Žagar, V.; Zidanšek, A.; Blinc, R.

2006-12-01

25

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

26

Nuclear Quadrupole Moments of the Neutron Deficient Isotopes 131CS and 132CS.  

National Technical Information Service (NTIS)

The nuclear quadrupole moments of 131Cs and 132Cs were measured by hyperfine structure spectroscopy of the 6(2)P3/2 and 7(2)P3/2 states with the methods of level crossing and optical double resonance. The following results (including the Sternheimer corre...

F. Ackermann E. W. Otten G. zu Putlitz A. Schenck S. Ullrich

1968-01-01

27

Dependence of Nuclear Quadrupole Relaxation Times in Ionic Crystals on the Phonon Spectrum  

Microsoft Academic Search

Nuclear quadrupole relaxation times are calculated for the halogen and alkali nuclei in a number of alkali halides using lattice phonon density curves computed by Karo. The calculated values of T1 at room temperature are generally lower than those obtained using the Debye model and in better agreement with experiment. The variation of T1 with temperature has also been calculated

S. K. Joshi; R. Gupta; T. P. Das

1964-01-01

28

Ab initio determination of the nuclear quadrupole moments of {sup 114}In, {sup 115}In, and {sup 117}In  

SciTech Connect

We present here ab initio determinations of the nuclear-quadrupole moment Q of hyperfine-probe-nuclear states of three different In isotopes: the 5{sup +} 192 keV excited state of {sup 114}In (probe for nuclear quadrupole alignment spectroscopy), the 9/2{sup +} ground state of {sup 115}In (nuclear magnetic and nuclear quadrupole resonance probe), and the 3/2{sup +} 659 keV excited state of {sup 117}In (perturbed angular correlations probe). These nuclear-quadrupole moments were determined by comparing experimental nuclear-quadrupole frequencies to the electric field gradient tensor calculated with high accuracy at In sites in metallic indium within the density functional theory. These ab initio calculations were performed with the full-potential linearized augmented plane wave method. The results obtained for the quadrupole moments of {sup 114}In [Q({sup 114}In)=-0.14(1) b] are in clear discrepancy with those reported in the literature [Q({sup 114}In)=+0.16(6) b and +0.739(12) b]. For {sup 115}In and {sup 117}In our results are in excellent agreement with the literature and in the last case Q({sup 117}In) is determined with more precision. In the case of Q({sup 117}In), its sign cannot be determined because standard {gamma}-{gamma} perturbed angular correlations experiments are not sensitive to the sign of the nuclear-quadrupole frequency.

Errico, Leonardo A.; Renteria, Mario [Departamento de Fisica-IFLP (CONICET), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, C.C. 67, 1900 La Plata (Argentina)

2006-03-15

29

Nuclear Schiff moment in nuclei with soft octupole and quadrupole vibrations  

NASA Astrophysics Data System (ADS)

Nuclear forces violating parity and time reversal invariance (P,T-odd) produce P,T-odd nuclear moments, for example, the nuclear Schiff moment. In turn, this moment can induce the electric dipole moment in the atom. The nuclear Schiff moment is predicted to be enhanced in nuclei with static quadru pole 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 this article in the framework of the quasiparticle random phase approximation with separable quadrupole and octupole forces applied to the odd Ra217-221 and Rn217-221 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. According to the QRPA, in realistic cases the enhancement in spherical nuclei is strongly reduced by a small weight of the corresponding “particle + phonon” component in a complicated wave function of a soft nucleus. The perspectives of a better description of the structure of heavy soft nuclei are discussed.

Auerbach, N.; Dmitriev, V. F.; Flambaum, V. V.; Lisetskiy, A.; Sen'kov, R. A.; Zelevinsky, V. G.

2006-08-01

30

Nuclear Quadrupole Resonance Studies of Charge Distributions in Molecular Solids.  

NASA Astrophysics Data System (ADS)

A detailed description of an NMR-NQR double resonance spectrometer designed and constructed in this laboratory is given, including some instruction on its use. ('14)N NQR data obtained by pulse methods for six classes of nitrogen-containing compounds are presented and analyzed in the framework of the Townes and Dailey theory. A study of the anti-cancer drugs cyclophosphamide, isophosphamide and triphosphamide suggests the existence of a correlation between the substance's chemotherapeutic efficacy and the (pi) - (sigma)(,NP) charge density at the trigonal nitrogen. Satisfactory correlations of the NQR spectra of 22 monosubstituted anilines with both the Hammett (sigma) parameters and the in vitro biological activities of the corresponding sulfanilamides have been found, indicating that the nitrogen lone-pair orbital is more sensitive than the nitrogen-carbon sigma orbital is to substituent effects. NQR spectra of several N-acetyl amino acids and related compounds are reported. The inductive effect of the chloroacetyl group on the nitrogen is discussed. A positive correlation between the (pi) - (sigma)(,NC) electron density at the nitrogen and the Taft inductive parameter (sigma)* is observed, suggesting that the nitrogen (pi) -charge density in the N-acetyl amino acids does not vary appreciably. Both ('14)N and ('35)Cl NQR data have been obtained for a series of compounds containing nitrogen directly bonded to chlorine. The existence of a linear correlation between the ('14)N and ('35)Cl quadrupole coupling constants is interpreted in terms of a simple model dealing with charge excesses and deficiencies at the respective nuclei. A study of two complexes of 4-aminopyridine (4AP) addresses the loss of pyridine nitrogen lone-pair charge upon formation of the strong and asymmetric N-H-N bond characteristic of these complexes. Evidence of hydrogen bonding interactions involving the amino nitrogens is found to be in agreement with a published neutron diffraction study. ('14)N NQR data for seven organic dye cations and one free base are presented. The cations are weakly paramagnetic at 77 K, exhibiting broad and featureless EPR spectra characteristic of weak charge-transfer complexes. The positive charge in the cations is largely delocalized. The existence of a simple relationship between the ('14)N NQR data and optical properties for three cyanine laser dyes is discussed.

Greenbaum, Steven Garry

31

On the theoretical description of nuclear quadrupole coupling in ? states of small molecules  

NASA Astrophysics Data System (ADS)

Axial (eQq0) and perpendicular (eQq2) nuclear quadrupole coupling constants were evaluated from the electric field gradient at the quadrupolar nuclei (7Li, 14N, 17O, 33S, 35Cl) in diatomic (LiO, CN, NH+, NH, N2+, NO, OH, HCl+, CCl, OCl, NS) and polyatomic (C2N, C4N, NCO, N3) ? states. For diatomics the nuclear quadrupole coupling constants (NQCCs) were determined as a function of the vibrational quantum number. The calculations were performed using the internally contracted multireference configuration interaction and single-configuration coupled-cluster approaches with large correlation-consistent basis sets. The overall quality of the wave functions was tested by comparing the calculated electric dipole moments and diatomic spectroscopic constants with external data. The calculated NQCCs were discussed and compared with previous experimental and theoretical studies.

Fišer, J.; Polák, R.

2013-11-01

32

Utilization of pure nuclear quadrupole resonance spectroscopy for the study of pharmaceutical crystal forms.  

PubMed

Solid-state physical characterization of a pharmaceutical substance is necessary for successful development and approval of the final product. Different physical analytical techniques are available to do so: X-ray diffraction (XRD), IR, Raman, DSC, TG and NMR. Moreover, all of them detect the presence of excipients perturbing the analysis of the pure substance in low doses. In order to study polymorphism and pseudo polymorphism of drug, this paper introduces possible applications of pure nuclear quadrupole resonance, as a non-destructive technique in qualitative and quantitative approaches. Chlorpropamide and diclofenac sodium were used as examples. Unlike the mentioned techniques, the nuclear quadrupole resonance (NQR) signal of pharmaceutical compounds is not perturbed by the presence of solid excipient or other substances unless they possess resonance frequencies in the same frequency range of the compound studied. PMID:15913931

Pérez, S C; Cerioni, L; Wolfenson, A E; Faudone, S; Cuffini, S L

2005-07-14

33

INSTRUMENTS AND METHODS OF INVESTIGATION: New technologies: nuclear quadrupole resonance as an explosive and narcotic detection technique  

NASA Astrophysics Data System (ADS)

Possibilities of detecting nuclear quadrupole resonance (NQR) signals in explosives and drugs are considered. Direct and indirect NQR techniques for searching substances are described and the potentialities of various experimental methods are compared.

Grechishkin, Vadim S.; Sinyavskii, Nikolai Ya

1997-04-01

34

In-Situ Real Time Detection of Explosive/Chemical Compounds in Mines Using Nuclear Quadrupole Resonance (NQR).  

National Technical Information Service (NTIS)

This program was part of DARPA's 'Dog Nose' initiative to develop land mine detection technology based upon the chemical signature of the mine explosive charge. Nuclear quadrupole resonance (NQR) was the only technology pursued that detects the bulk explo...

A. D. Hibbs

2001-01-01

35

Correlation of Nuclear Quadrupole Interaction Frequencies with Polarographic Half-Wave Potentials  

Microsoft Academic Search

WHEN the nuclear quadrupole interaction frequencies of some aryl iodo-compounds are plotted against the corresponding half-wave potentials of these compounds at pH 7 (Fig. 1) a general linear trend is obvious; but the departure from linearity in the case of the iodoanilines is more serious (points not shown on graph). The data are taken from results obtained by E. Gergely

T. Iredale

1956-01-01

36

Nuclear Magnetic Resonance and Quadrupole Effects in KBr and NaBr Single Crystals  

Microsoft Academic Search

Nuclear-magnetic-resonance pulse techniques have been applied to the study of first-order quadrupole broadening of the satellites for the bromine nucleus in alkali halide crystals. From the analysis of the free precession, the shape and the width of the satellite line can be obtained. For KBr and NaBr it has been found that the satellite line has a Lorentz shape, and

G. Bonera; A. Avogadro; F. Borsa

1968-01-01

37

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

38

Nuclear quadrupole interaction and nonlinear optical property of some borate crystals^*  

NASA Astrophysics Data System (ADS)

Borate crystals, like Li_2B_4O_7, LiB_3O_5, and BaB_2O_4, consist of 4-coordinated and/or 3-coordinated boron-oxygen bonds. As reported [1], the principal Z-axis of the electric field gradient (EFG) around the boron in 3-coordinated bonds is perpendicular to the plane containing the boron-oxygen bonds. We calculated the principal Z-direction of the EFG-tensor by employing the simple point charge model for the arbitrary planar triangle configurations, and the results are consistent with experimental ones. Moreover, a strong correlation between the nonlinear optical coefficient and the nuclear quadrupole interactions, such as the quadrupole coupling constant and the asymmetry parameter, was empirically found for these compounds. Details will be presented. * Supported by the National Research Laboratory Program(MOST). [1] I. G. Kim and S. H. Choh, J. Phys.: Condens. Matter, b11, 8283 (1999).

Choh, S. H.; Kim, I. G.; Shin, H. W.; Park, I.-W.

2003-03-01

39

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

40

Hartree-Fock cluster investigations of electronic structure and nuclear quadrupole interaction in the superionic conductor Li 3 N  

Microsoft Academic Search

The nuclear quadrupole interactions for7Li and14N nuclei are studied for lithium nitride crystal using the Hartree-Fock cluster procedure to obtain the electronic structure. The influence of the Madelung potential due to the ions outside the cluster was incorporated in a first-principle manner. Our results for the quadrupole coupling constants will be compared with experimental data and the results of a

P. C. Kelires; K. C. Mishra; T. P. Das

1987-01-01

41

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

42

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

NASA Astrophysics Data System (ADS)

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

Seliger, J.; Žagar, V.

2008-07-01

43

Discriminating the structure of exo-2-aminonorbornane using nuclear quadrupole coupling interactions  

NASA Astrophysics Data System (ADS)

The intrinsic conformational and structural properties of the bicycle exo-2-aminonorbornane have been probed in a supersonic jet expansion using Fourier-transform microwave (FT-MW) spectroscopy and quantum chemical calculations. The rotational spectrum revealed two different conformers arising from the internal rotation of the amino group, exhibiting small (MHz) hyperfine patterns originated by the 14N nuclear quadrupole coupling interaction. Complementary ab initio (MP2) and DFT (B3LYP and M05-2X) calculations provided comparative predictions for the structural properties, rotational and centrifugal distortion data, hyperfine parameters, and isomerization barriers. Due to the similarity of the rotational constants, the structural assignment of the observed rotamers and the calculation of the torsion angles of the amino group were based on the conformational dependence of the 14N nuclear quadrupole coupling hyperfine tensor. In the most stable conformation (ss), the two amino N-H bonds are staggered with respect to the adjacent C-H bond. In the second conformer (st), only one of the N-H bonds is staggered and the other is trans. A third predicted conformer (ts) was not detected, consistent with a predicted conformational relaxation to conformer ss through a low barrier of 5.2 kJ mol-1.

Écija, Patricia; Cocinero, Emilio J.; Lesarri, Alberto; Millán, Judith; Basterretxea, Francisco; Fernández, José A.; Castaño, Fernando

2011-04-01

44

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

45

Finite element multiconfiguration Hartree-Fock calculations on carbon, oxygen, and neon: The nuclear quadrupole moments of {sup 11}C, {sup 17}O, and {sup 21}Ne  

SciTech Connect

The authors report new calculations for the nuclear quadrupole moments of {sup 11}C, {sup 17}O, and {sup 21}Ne, making use of a new finite-element multiconfiguration Hartree-Fock method. They calculate electric field gradients at the nuclei and combine these with measurements of nuclear quadrupole coupling constants to arrive at the values.

Sundholm, D. [Univ. of Helsinki (Finland); Olsen J. [Univ. of Lund (Sweden)

1992-01-23

46

14N pulsed nuclear quadrupole resonance. 1. Nutation experiments in the case of an axially symmetric electric field gradient tensor  

Microsoft Academic Search

An exact theory based on density matrix calculations is provided for assessing the nuclear quadrupole resonance (NQR) behaviour of a spin 1 (14N) subjected to a single radio-frequency pulse. It concerns a powder sample in zero magnetic field with the assumption of an axially symmetric electric field gradient tensor. Theoretical results, in terms of signal evolution as a function of

B. Cordier; D. Grandclaude; A. Retournard; L. Merlat; D. Canet

2005-01-01

47

14N Pulsed nuclear quadrupole resonance. 2. Effect of a single radio-frequency pulse in the general case  

Microsoft Academic Search

A novel theory, based on density operator calculations, is provided for assessing the nuclear quadrupole resonance behaviour of a spin 1 (14N) subjected to a single radio-frequency pulse. It is for a powder sample in zero magnetic field for an electric field gradient tensor without symmetry. A complete set of equations is obtained for the quantities of interest. It is

Daniel Canet; Lionel Merlat; Benoit Cordier; Denis Grandclaude; Alain Retournard; Maude Ferrari

2006-01-01

48

Crystallization of an amorphous solid studied by nuclear quadrupole double resonance  

NASA Astrophysics Data System (ADS)

Nuclear quadrupole double resonance (NQDR) is proposed as a method for quantitative observation of crystallization of amorphous solids. NQDR signals from amorphous and crystalline parts of a sample may be separated. The intensity I of the NQDR signal from the crystalline part of the sample is proportional to its mass. With increasing time the amorphous phase in the sample transforms to the crystal phase and the intensity I approaches its limiting value I0 corresponding to the complete transformation to the crystal phase. The ratio I/I0 is equal to the mass fraction of the crystalline part of the sample. The same experimental method can be used to determine the mass fraction of a given crystal polymorph in a mixture of crystal polymorphs. As an example we studied crystallization of amorphous nifedipine at 100 °C. The results of the NQDR study are compared to the published results of other studies.

Seliger, Janez; Žagar, Veselko

2013-06-01

49

Enhancing nuclear quadrupole resonance (NQR) signature detection leveraging interference suppression algorithms  

NASA Astrophysics Data System (ADS)

Nuclear quadrupole resonance (NQR) is a radio frequency (RF) magnetic spectroscopic technique that has been shown to detect and identify a wide range of explosive materials containing quadrupolar nuclei. The NQR response signal provides a unique signature of the material of interest. The signal is, however, very weak and can be masked by non-stationary RF interference (RFI) and thermal noise, limiting detection distance. In this paper, we investigate the bounds on the NQR detection range for ammonium nitrate. We leverage a low-cost RFI data acquisition system composed of inexpensive B-field sensing and commercial-off-the-shelf (COTS) software-defined radios (SDR). Using collected data as RFI reference signals, we apply adaptive filtering algorithms to mitigate RFI and enable NQR detection techniques to approach theoretical range bounds in tactical environments.

DeBardelaben, James A.; Miller, Jeremy K.; Myrick, Wilbur L.; Miller, Joel B.; Gilbreath, G. Charmaine; Bajramaj, Blerta

2012-05-01

50

Detection of TNT and RDX landmines by standoff nuclear quadrupole resonance  

NASA Astrophysics Data System (ADS)

Nuclear Quadrupole Resonance (NQR) combines the compound specific detection capability offered by chemical offered by chemical detection techniques with the spatial coating capability and convenience of an induction coil metal detector. In this paper we present the first results of the detection of TNT by NQR with sufficient for detection of many antipersonnel mines and essentially all antitank mines. In addition, we review the result of a blind in-field demonstration of the system in detecting RDX in which 28 out of 31 RDX-only targets were found with 1 false alarm in a 110 m test lane, and a second test in which 21 out of 21 RDX mines were found with zero false alarms at a clearance rate of 1.1 m2 per minute.

Hibbs, Andrew D.; Barrall, Geoffrey A.; Czipott, Peter V.; Drew, A. J.; Gregory, Dave; Lathrop, Daniel K.; Lee, Y. K.; Magnuson, Erik E.; Matthews, Robert; Skvoretz, D. C.; Vierkoetter, Stephie A.; Walsh, David O.

1999-08-01

51

Heavy Fermion Superconductor Ce2PdIn8 studied by 115In Nuclear Quadrupole Resonance  

NASA Astrophysics Data System (ADS)

We have performed nuclear quadrupole resonance (NQR) measurements on a recently-discovered heavy-fermion superconductor Ce2PdIn8 with superconducting critical temperature Tc = 0.64 K. Below coherent temperature Tcoh ~ 30 K, the spin-lattice relaxation rate 1/T1 decreases with decreasing temperature T and is proportional to T1/2 between Tc and Tcoh. This is clearly different from the Fermi-liquid behavior in which the T dependence is proportional to T, and indicates that Ce2PdIn8 is located on the verge of antiferromagnetic quantum critical point from the view point of the NQR. Below Tc, 1/T1 shows no coherence peak and is proportional to T3. This is clear evidence for the realization of unconventional superconductivity with line nodes in this compound.

Fukazawa, H.; Nagashima, R.; Shimatani, S.; Kohori, Y.; Kaczorowski, D.

2013-07-01

52

Rabi and Larmor nuclear quadrupole double resonance of spin-1 nuclei  

NASA Astrophysics Data System (ADS)

We demonstrate the creation of two novel double-resonance conditions between spin-1 and spin-1/2 nuclei in a crystalline solid. Using a magnetic field oscillating at the spin-1/2 Larmor frequency, the nuclear quadrupole resonance (NQR) frequency is matched to the Rabi or Rabi plus Larmor frequency, as opposed to the Larmor frequency as is conventionally done. We derive expressions for the cross-polarization rate for all three conditions in terms of the relevant secular dipolar Hamiltonian, and demonstrate with these expressions how to measure the strength of the heterogenous dipolar coupling using only low magnetic fields. In addition, the combination of different resonance conditions permits the measurement of the spin-1/2 angular momentum vector using spin-1 NQR, opening up an alternate modality for the monitoring of low-field nuclear magnetic resonance. We use ammonium nitrate to explore these resonance conditions, and furthermore use the oscillating field to increase the signal-to-noise ratio per time by a factor of 3.5 for NQR detection of this substance.

Prescott, D. W.; Malone, M. W.; Douglass, S. P.; Sauer, K. L.

2012-12-01

53

Thermal Conductivity of Glasses Induced by Nuclear Quadrupole Interaction at Ultra Low Temperatures  

NASA Astrophysics Data System (ADS)

It is investigated how nuclear degrees of freedom of tunneling system (TS) inherent in amorphous solids influence its acoustic properties. It was shown in our previous papers that below 10 mK nuclear quadrupole interaction breaks down the coherent tunneling. This phenomenon results in appearance of the quasi-gap in the distribution function for the tunneling amplitude splitting. The quasi-gap is responsible for the plateau in the temperature dependence of the real part of a dielectric permittivity or speed of sound. In this paper we are interested in ultrasonic absorption and thermal conductivity which are intimately connected. We demonstrate that there exists a temperature interval in a millikelvin region where the sound absorption behavior changes drastically from the behavior predicted by the standard tunneling model (STM). In particular, the sound absorption increases approximately by an order of magnitude. Since in the millikelvin region the heat transport is due to acoustic phonons, the thermal conductivity also should demonstrate a strong increase as compared to standard tunneling model. The application of a strong magnetic field is known to restore the coherent tunneling and the standard distribution for the tunneling splitting amplitude. Thus, one can expect that in a strong magnetic field the thermal conductivity should drop in the temperature interval where the coherent tunneling was initially destroyed.

Polishchuk, I. Y.; Burin, A. L.

2011-03-01

54

Temperature dependence of nuclear quadrupole coupling constant of ^7Li and ^93Nb in LiNbO_3^*  

NASA Astrophysics Data System (ADS)

It is well established that the ferroelectricity of LiNbO3 originates from the displacement of positive ions, lithium and niobium, relative to negative oxygen ions below T_c. The local structural environment of Li and Nb in the crystal is similar at room temperature. However, as the temperature increases they move opposite directions along the c-axis: Li ions move to the center of oxygen triangles while Nb move to the center of oxygen octahedra. The temperature dependence of the nuclear quadrupole coupling constant(QCC) of Li and Nb is quite different: the QCC of ^7Li increases while that of ^93Nb decreases as the temperature increases[1]. In order to understand this opposite tendency we calculated the electric field gradient(EFG) at the two sites due to the first and second nearest neighboring oxygen ions, by considering the effective charges. The calculated results turn out to be in good agreement with the temperature dependence of QCC for both cations in the crystal. * Supported by the National Research Laboratory Program(MOST). [1] H. J. Kim and S. H. Choh, J. Korean Phys. Soc. b28, 513 (1995).

Park, I.-W.; Choh, S. H.; Kim, H. J.; Kim, J. H.; Yoon, M.

2003-03-01

55

Steady-State Nuclear Double-Resonance Detection of Electric Quadrupole Moment of Potassium-40.  

National Technical Information Service (NTIS)

Several resonances associated with the K 40 pure electric quadrupole interaction in KClO3 have been detected which allow the determination of the K 40-K 39 electric quadrupole moment ratio Q40/Q39 (1.244 + or - 0.002) and the asymmetry parameter eta(0.621...

E. P. Jones S. R. Hartmann

1969-01-01

56

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

57

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, M. L.; Yesinowski, J. P.; Miller, J. B.

1994-03-01

58

Nuclear quadrupole moment of {sup 43}Ca and hyperfine-structure studies of its singly charged ion  

SciTech Connect

By combining our theoretical calculation and the recently measured electric quadrupole hyperfine-structure constant of the 3d {sup 2}D{sub 5/2} state in the singly ionized {sup 43}Ca, we determine its nuclear quadrupole moment to 1% accuracy. The obtained result, -0.0444(6)b, is about 10% more accurate over its current accepted value. We have employed the relativistic coupled-cluster theory at the single and double excitations level to calculate the atomic wave functions. The accuracy of these wave functions is estimated by comparing our calculated magnetic dipole hyperfine constants with their corresponding available experimental results of many low-lying states. We also present hyperfine-structure constants for other higher excited states where experimental results are not reported. The role of the Breit interaction has been investigated in these properties.

Sahoo, B. K. [KVI, University of Groningen, NL-9747 AA Groningen (Netherlands)

2009-07-15

59

Nuclear quadrupole moment of C43a and hyperfine-structure studies of its singly charged ion  

NASA Astrophysics Data System (ADS)

By combining our theoretical calculation and the recently measured electric quadrupole hyperfine-structure constant of the 3dD25/2 state in the singly ionized C43a , we determine its nuclear quadrupole moment to 1% accuracy. The obtained result, -0.0444(6)b , is about 10% more accurate over its current accepted value. We have employed the relativistic coupled-cluster theory at the single and double excitations level to calculate the atomic wave functions. The accuracy of these wave functions is estimated by comparing our calculated magnetic dipole hyperfine constants with their corresponding available experimental results of many low-lying states. We also present hyperfine-structure constants for other higher excited states where experimental results are not reported. The role of the Breit interaction has been investigated in these properties.

Sahoo, B. K.

2009-07-01

60

Magnetic-field-induced quadrupole coupling in the nuclear magnetic resonance of noble-gas atoms and molecules  

SciTech Connect

An analytic response theory formulation for the leading-order magnetic field-induced and field-dependent quadrupole splitting in nuclear magnetic resonance spectra is presented and demonstrated with first-principles calculations for {sup 21}Ne, {sup 36}Ar, and {sup 83}Kr in noble gas atoms. The case of molecules was studied for {sup 33}S in the sulphur hexafluoride molecule, as well as for {sup 47/49}Ti, {sup 91}Zr, and {sup 177,179}Hf in group(IV) tetrahalides. According to our calculations, the hitherto experimentally unknown field-induced quadrupole splitting in molecules rises to 10{sup 2} Hz for {sup 177,179}Hf nuclei in HfF{sub 4} and 10{sup 1} Hz for {sup 47/49}Ti in TiCl{sub 4}, and is hence of observable magnitude.

Manninen, Pekka [Laboratory of Physical Chemistry, Department of Chemistry, P.O. Box 55 (A.I. Virtasen aukio 1), FIN-00014 University of Helsinki (Finland); NMR Research Group, Department of Physical Sciences, P.O. Box 3000, FIN-90014 University of Oulu (Finland); Vaara, Juha [Laboratory of Physical Chemistry, Department of Chemistry, P.O. Box 55 (A.I. Virtasen aukio 1), FIN-00014 University of Helsinki (Finland); Pyykkoe, Pekka [Laboratory for Instruction in Swedish, Department of Chemistry, P.O. Box 55 (A.I. Virtasen aukio 1), FIN-00014 University of Helsinki (Finland)

2004-10-01

61

WURST-QCPMG sequence and "spin-lock" in ¹?N nuclear quadrupole resonance.  

PubMed

¹?N nuclear quadrupole resonance (NQR) is a promising method for the analysis of pharmaceuticals or for the detection of nitrogen based illicit compounds, but so far, the technique is still not widely used, mostly due to the very low sensitivity. This problem is already acute in the preliminary NQR stage, when a compound is being examined for the first time and the NQR frequencies are being searched for, by scanning a wide frequency range step-by-step. In the present work, we experimentally show how to increase the efficiency of this initial stage by using a combination of a wideband excitation achieved with frequency swept pulses (WURST) and a "spin-lock" state obtained with a quadrupolar-CPMG (QCPMG) sequence. In the first part we show that WURST pulses provide a much larger excitation bandwidth compared to common rectangular pulses. This increased bandwidth allows to increase the frequency step and reduces the total number of steps in a scanning stage. In the second part we show that the "spin-lock" decay time T2eff obtained with the WURST-QCPMG combination is practically identical with the T2eff obtained with the most common "spin-lock" sequence, the SLSE, despite a very different nature and length of excitation pulses. This allows for a substantial S/N increase through echo averaging in every individual step and really allows to exploit all the advantages of the wider excitation in the NQR frequency scanning stage. Our experimental results were obtained on a sample of trinitrotoluene, but identical behavior is expected for all compounds where a "spin-lock" state can be created. PMID:23793057

Gregorovi?, Alan; Apih, Tomaž

2013-06-04

62

Spectral hole-burning study of hyperfine and nuclear quadrupole interactions of {sup 243}Am{sup 3+} in CaWO{sub 4}  

SciTech Connect

An optical spectral hole-burning technique has been used in study of the hyperfine and nuclear quadrupole interactions of {sup 243}Am{sup 3+} in CaWO{sub 4}. Previous work on {sup 243}Am{sup 3+} in LaCl{sub 3} [Phys. Rev. B {bold 53}, 2385 (1996)] provided an analysis of the nuclear quadrupole interaction in the {sup 7}F{sub 0} ground state and predicted an anomalous nuclear quadrupole interaction in the optically excited state {sup 5}D{sub 1}. In the present work on {sup 243}Am{sup 3+} doped into CaWO{sub 4}, hyperfine energy levels in both the {sup 7}F{sub 0} ground state and the {sup 5}D{sub 1} excited state of an {sup 243}Am{sup 3+} ion have been resolved in spectral hole-burning experiments. A theoretical analysis is reported for the hyperfine and nuclear quadrupole interactions in the non-Kramers doublet of the {sup 5}D{sub 1} excited state of {sup 243}Am{sup 3+} in CaWO{sub 4}. Whereas the crystal-field antishielding effect dominates the ground state nuclear quadrupole splitting, a first order electronic hyperfine interaction dominates the excited state splitting. It is shown that the contribution from the nuclear electric quadrupole interactions in the {sup 5}D{sub 1} excited state is much smaller than that in the {sup 7}F{sub 0} ground state, because the first order nuclear quadrupole interaction with the 5f electrons is canceled in part by the contribution from the lattice interaction. {copyright} {ital 1997} {ital The American Physical Society}

Liu, G.K. [Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Huang, J. [Department of Physics and Astronomy, University of Wisconsin at Eau Claire, Eau Claire, Wisconsin 54702 (United States); Abraham, M.M. [Solid State Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

1997-04-01

63

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

64

MOLECULAR STRUCTURES OF PCl4F, PCl3F2, AND PCl2F3: PURE CHLORINE NUCLEAR QUADRUPOLE RESONANCE AND LOW TEMPERATURE F NUCLEAR MAGNETIC RESONANCE SPECTRA  

Microsoft Academic Search

Chlorine nuclear quadrupole resonance spectra determined at 77°K. and F n.m.r. data obtained as a function of temperature for the molecular forms of PCl4,F, PCl3F2, and PCl2F3 were correlated with previous infrared and Raman spectra. The data support the trigonal bipyramid as the structural model for the halides with fluorine atoms showing a preference for axial positions. The symmetry of

Robert R. Holmes; Richard P. Carter Jr; George E. Peterson

1995-01-01

65

Nuclear Quadrupole Moments as a Microscopic Probe to Study the Motion of Atomic Tunneling Systems in Amorphous Solids  

NASA Astrophysics Data System (ADS)

The properties of amorphous solids below 1 K are dominated by atomic tunneling systems. A basic description is given by the standard tunneling model. Despite its success, the standard tunneling model still remains phenomenological and little is known about the microscopic nature of tunneling systems in amorphous solids. We present dielectric polarization echo experiments on partially deuterated amorphous glycerol. Nuclear quadrupoles, introduced by the deuteration, influence the echo amplitude in a characteristic way and allow us to draw for the first time detailed conclusions about the microscopic nature of the tunneling processes in amorphous glycerol.

Bartkowiak, M.; Bazrafshan, M.; Fischer, C.; Fleischmann, A.; Enss, C.

2013-05-01

66

Charge-inhomogeneity doping relations in Y Ba2 Cu3 Oy detected by angle-dependent nuclear quadrupole resonance  

NASA Astrophysics Data System (ADS)

The origin of charge inhomogeneity in YBa2Cu3Oy is investigated using an experimental method designed to determine the nuclear quadrupole resonance (NQR) asymmetry parameter ? for very wide NQR lines at different positions on the line. The method is based on the measurement of the echo intensity as a function of the angle between the radio frequency field H1 and the principal axis of the electric field gradient. Static charge inhomogeneity deduced from ?>0 is found in this compound, but only in conjunction with oxygen deficiency. This limits considerably the possible forms of charge inhomogeneity in bulk YBa2Cu3Oy .

Ofer, Rinat; Levy, Shahar; Kanigel, Amit; Keren, Amit

2006-01-01

67

Toward understanding the effects of nuclear war  

Microsoft Academic Search

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

Herbert D. Grover; Gilbert F. White

1985-01-01

68

Understanding and Managing North Korea's Nuclear Ambitions.  

National Technical Information Service (NTIS)

The February 2007 agreement reached with North Korea to shut down its nuclear reactor and give up its nuclear weapons program was heralded by many as a significant breakthrough following the shock of North Korea's nuclear weapons test in October of the pr...

G. E. Witt

2008-01-01

69

Electronic structure and indirect spin-spin interactions in bournonite (CuPbSbS3) according to antimony nuclear quadrupole resonance  

NASA Astrophysics Data System (ADS)

A complex sulfide CuPbSbS3 (bournonite) has been studied by the nuclear quadrupole resonance on 121,123Sb. The temperature dependences of the spectroscopic and relaxation parameters in the temperature range of 10-295 K have been obtained. The crystallochemical features of the environment of the two non-equivalent Sb positions in the unit cell have been revealed from the nuclear quadrupole resonance spectra. The existence of the lattice vibrations with the frequency ? = 110 cm-1 has been demonstrated on the basis of the temperature dependence of the nuclear quadrupole resonance frequencies. Slow beats have been observed on the decay curve of the spin echo signal. Experimental data have been analyzed in order to reveal the existence of the indirect spin-spin interactions involving Sb atoms. The indirect spin-spin coupling constant has been estimated as J = 2.5 ± 0.5 kHz.

Orlova, A. Yu.; Gainov, R. R.; Dooglav, A. V.; Pen'kov, I. N.

2013-06-01

70

Towards an understanding of the nuclear potential  

SciTech Connect

The formalism for investigating the /bar Q/q/bar Q/q system on the lattice is constructed. We describe how the model may be used to study the nuclear potential, and present some preliminary results on the range of the nuclear force. 6 refs., 4 figs., 1 tab.

Richards, D.G.; Sinclair, D.K.; Sivers, D.

1988-01-01

71

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

72

Finite element multiconfiguration Hartree-Fock calculations on carbon, oxygen, and neon: The nuclear quadrupole moments of ¹¹C, ¹⁷O, and ²¹Ne  

Microsoft Academic Search

The authors report new calculations for the nuclear quadrupole moments of ¹¹C, ¹⁷O, and ²¹Ne, making use of a new finite-element multiconfiguration Hartree-Fock method. They calculate electric field gradients at the nuclei and combine these with measurements of nuclear quadrupole coupling constants to arrive at the values.

D. Sundholm; Olsen J

1992-01-01

73

The quadrupole moment of 196Pt - A crucial test of nuclear models  

NASA Astrophysics Data System (ADS)

The static electric quadrupole moment ?2+ and the B(E2; 0+ --> 2+) of the first excited state of 196Pt have been determined using Coulomb excitation. The results are ?2+ = 0.79+/-0.12 eb and B(E2; 0+ --> 2+) = 1.382+/-0.006 e2b2. The Bohr-Mottel-son model and the O(6) limit of the interacting boson model fail to reproduce these values when constrained to fit other known. properties of 196Pt.

Fewell, M. P.; Gyapong, G. J.; Spear, R. H.; Esat, M. T.; Baxter, A. M.; Burnett, S. M.

1985-07-01

74

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

NASA Astrophysics Data System (ADS)

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, 152,154Sm, 154,156,158Gd, 236U, and 100Mo. 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 ? 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.

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

2012-03-01

75

Evidence of Antiferromagnetic Ordering in La/sub 2/CuO/sub 4/: Re-Interpretation of /sup 139/La Nuclear Quadrupole Resonance (NQR) Data.  

National Technical Information Service (NTIS)

A re-interpretation of the result of recent /sup 139/La nuclear quadrupole resonance measurements on La/sub 2/CuO/sub 4/ reveals an antiferromagnetic order in this material at low temperature. The magnitude and the direction of the local field at the La p...

I. Furo A. Janossy

1987-01-01

76

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

77

Co Nuclear-Quadrupole-Resonance Measurements on NaxCoO2.yH2O - Phase Diagram for Bilayered-Hydrate System  

Microsoft Academic Search

Co nuclear quadrupole resonance (NQR) measurements were performed on several superconducting (SC) NaxCoO2.yH2O samples with different values of a SC transition temperature (Tc). The measurements were done for the investigation of the relationship between Tc and microscopic physical quantities derived from the Co NQR. We measured Co-NQR frequency nuQ and the nuclear-lattice relaxation rate 1\\/T1 the Co site, and found

Yoshihiko Ihara; Hideo Takeya; Kenji Ishida; Chishiro Michioka; Kazuyoshi Yoshimura; Kazunori Takada; Takayoshi Sasaki; Hiroya Sakurai; Eiji Takayama-Muromachi

2006-01-01

78

Understanding Nuclear Receptors Using Computational Methods  

PubMed Central

Nuclear receptors (NRs) are important targets for therapeutic drugs. NRs regulate transcriptional activities through binding to ligands and interacting with a number of regulating proteins. Computational methods can provide insights into essential ligand-receptor and protein-protein interactions. These in turn have facilitated the discovery of novel agonists and antagonists with high affinity and specificity as well as aiding in the prediction of toxic side effects of drugs by identifying possible off-target interactions. Here, we review the application of computational methods towards several clinically important NRs (with special emphasis on PXR) and discuss their use for screening and predicting the toxic side effects of xenobiotics.

Ai, Ni; Krasowski, Matthew D.; Welsh, William J; Ekins, Sean

2010-01-01

79

Nuclear quadrupole interaction studies of C15 RMn{sub 2} hydrides (R=Y,Gd,Tb,Dy)  

SciTech Connect

The nuclear electric quadrupole interaction (QI) of the probe nucleus {sup 111}In/{sup 111}Cd in the paramagnetic phase of the C15 rare earth (R)-manganese hydrides (deuterides) RMn{sub 2}H(D){sub x}, with R=Y, Gd, Tb, and Dy, has been investigated by perturbed angular-correlation spectroscopy. The QI between the {sup 111}Cd quadrupole moment and the electric-field gradient (EFG) at the probe nucleus on the Mn site has been measured as a function of temperature in TbMn{sub 2}H(D){sub x} in the concentration range 0{<=}x{<=}4.3 and in RMn{sub 2}H(D){sub x}, R=Y,Gd,Dy at the highest H content of x{approx}4.3. The relative temperature dependence of the EFG in the parent compounds RMn{sub 2} is twice as strong as in isostructural RAl{sub 2} which can be related to differences in the Debye temperatures resulting from different radius ratios r{sub R}/r{sub Mn} and r{sub R}/r{sub Al}[Joseph-Gschneidner postulate, Scr. Metall.2, 631 (1968)]. Hydrogenation of RMn{sub 2} increases the magnitude of the EFG by a factor of 2 between x=0 and x=4.3 but leaves the relative temperature dependence almost unchanged. Only at concentrations x>3.6 the temperature coefficient of the QI is significantly larger than in uncharged RMn{sub 2}. These results are compared with the much stronger concentration dependence and the anomalous temperature dependence of the QI of {sup 111}Cd in the C15 hydrides HfV{sub 2}H{sub x}. Evidence for an exceptionally high H mobility in TbMn{sub 2}H{sub x} is presented. The measurements provide information on structural changes and magnetic ordering temperatures at different H concentrat0010io.

Forker, M.; Bedi, S. C. [Helmholtz Institut fuer Strahlen-und Kernphysik, University of Bonn, Nussallee 14-16, D-53115 Bonn (Germany); Euler, H. [Steinmann-Institut fuer Geologie, Mineralogie und Palaeontologie, University of Bonn, Poppelsdorfer Schloss, D-53115 Bonn (Germany)

2008-09-01

80

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

81

Paramagnetic Resonance Absorption in Uranium (III) Chloride and the Nuclear Spin, Magnetic Dipole Moment, and Electric Quadrupole Moment of Uranium233  

Microsoft Academic Search

Paramagnetic resonance absorption in single crystals of U233Cl3 diluted with LaCl3 has been investigated. The values of the parameters in the appropriate Hamiltonian are given. The values of the nuclear spin, magnetic dipole moment, and electric quadrupole moment obtained from these studies are discussed. The ratios of the mo ments of U235 and U233, which can be obtained with much

Paul B. Dorain; Clyde A. Hutchison; Eugene Wong

1957-01-01

82

Nuclear Quadrupole Coupling and Crystal-Field Effects in the Cubic Intermetallic Compounds ErAl3, TmAl3, and YbAl3  

Microsoft Academic Search

The presence of a large nuclear quadrupole coupling of the Al nucleus, as measured with NMR, in the cubic rare-earth aluminum intermetallic compounds beta-ErAl3, TmAl3, and YbAl3 indicates that the net charges at the rare-earth and aluminum sites differ by as much as 3 to 4 unit charges. Data on the magnetic susceptibility and this result have been used to

H. W. de Wijn; A. M. van Diepen; K. H. Buschow

1970-01-01

83

Dynamic orientational disorder of the nitro group in 2-chloro-nitrobenzene revealed through 35 Cl nuclear quadrupole resonance  

NASA Astrophysics Data System (ADS)

In the present paper we analyse the contributions of nitro group movements in 2-chloro-nitrobenzene to the nuclear quadrupole resonance (NQR) parameters of the chlorine nucleus in the molecule. We found two contributions to the spin-lattice relaxation time (T1) and the NQR frequency (?Q) due to the onset of nitro group movements in the molecule. One of these contributions is the well-known semirotation of the nitro group around the N-C axis. The other one is attributed to some tilting or tipping of the nitro plane away from the benzene ring introducing some dynamic orientational disorder of this group in the crystal only observed as a contribution from the temperature dependence of T1 and ?Q. Its activation energy is similar to that of the nitro group reorientation (21.9 and 23.6 kJ mol-1 for the two processes) and may arise from competing crystalline and steric chlorine nucleus effects. The present investigation shows that in chloronitrobenzenes the NO2 group dynamic orientational disorder can produce modulation effects on the chlorine T1 which are large enough to be observed by means of the NQR.

Brunetti, Aldo H.

2002-09-01

84

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

85

Nuclear Power and the Environment, Understanding the Atom Series.  

ERIC Educational Resources Information Center

|This booklet is one of the booklets in the "Understanding the Atom Series" published by the U. S. Atomic Energy Commission for high school science teachers and their students. Discussion concentrates on the radiological and thermal aspects of the environmental effects of nuclear power plants; on the procedures followed by the Atomic Energy…

Atomic Energy Commission, Oak Ridge, TN. Div. of Technical Information.

86

The public's understanding of radiation and nuclear waste  

Microsoft Academic Search

In order to understand ordinary people's attitudes towards radiation it is necessary to explore not just their opinions but also their knowledge, beliefs, feelings and actions. Findings are presented from various surveys that detail how the public define radiation and radioactive waste; what they imaging could happen to a local community living near a nuclear facility; and the actions they

J. M. Brown; H. M. White

1987-01-01

87

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

88

Nuclear quadrupole interactions of 111In/Cd solute atoms in a series of rare-earth palladium alloys  

NASA Astrophysics Data System (ADS)

Nuclear quadrupole interactions were measured at 111In/Cd probe atoms in rare-earth palladium phases RPd3 having the L12 structure using the technique of perturbed angular correlation of gamma rays (PAC). Measurements were made for pairs of samples having compositions of the Pd-poorer and Pd-rich boundaries of the RPd3 phase fields, typically 75 and 78 at.% Pd. Two signals were detected in most phases, corresponding to probe atoms on cubic R- and non-cubic Pd-sublattices. Site preferences of parent In-probe atoms were characterized by site-fractions of probes on the R- and Pd-sublattices. For all Pd-rich samples, probes exclusively occupied the R-sublattice, consistent with a heuristic rule that solute atoms tend to occupy the sublattice of an element in which there is a deficiency. For Pd-poorer alloys with R = Tb, Er, Yb, Lu, Y and Sc, probes exclusively occupied the Pd-sublattice. For Pd-poorer alloys with R = Ce, Pr, Nd, Sm and Eu, probes occupied both sublattices, with site fractions varying as a function of temperature. In contrast, probes only occupied the R-sublattice in Pd-poorer LaPd3. Jump frequencies on the Pd-sublattice of daughter Cd-probes were determined from nuclear relaxation caused by fluctuating electric field gradients. Activation enthalpies for diffusional jumps were determined from temperature dependences and found to increase linearly as the lattice parameter decreases along the series Pr, Nd, Eu and Sm. Jump frequencies are believed to have been even higher in CePd3 than in PrPd3, but were too low to be detectable in Tb, Er, Yb, Lu, Y and Sc palladides. A correlation between site preferences and jump frequencies is noted and discussed. This paper provides a complete account of measurements of jump frequencies of Cd-probe atoms and comparisons with similar measurements made on other series of L12 phases.

Wang, Qiaoming; Collins, Gary S.

2012-11-01

89

Hydrogen bonds in cocrystals and salts of 2-amino-4,6-dimethylpyrimidine and carboxylic acids studied by nuclear quadrupole resonance.  

PubMed

(14)N and (17)O nuclear quadrupole resonance frequencies have been measured in 1:1 cocrystals and salts of 2-amino-4,6-dimethylpyrimidine and several carboxylic acids. A systematic decrease of the (17)O quadrupole coupling constant on increasing strength of the hydrogen bond is observed in cocrystals bound by O-H···N hydrogen bonds. The O-H distances deduced from the line widths of the (17)O NQR lines show that the hydrogen atom is in a hydrogen bond formed by a carboxylic groups for about 0.01 nm displaced from the oxygen atom toward the center of the hydrogen bond. In the O-H···N hydrogen bond formed by the hydroxyl group, which is only slightly longer than the hydrogen bonds formed by the carboxyl group, the hydrogen atom is much less displaced. A linear relation between the (14)N quadrupole coupling constant and the sum of the inverse third powers of the H···A (A = O or N) distances is deduced for the amino group. A linear correlation of the principal values of the (14)N quadrupole coupling tensor in -NH2, as observed in the solid phase and in the gas phase, is analyzed in a simple model assuming a displacement of the electron charge in the N-H ? bond and simultaneous deformation of the nitrogen lone pair electron orbital. At the ring nitrogen position, hydrogen bonding and proton transfer produce a large decrease of the (14)N quadrupole coupling constant. A linear correlation of the principal values of the (14)N quadrupole coupling tensor is observed in cocrystals and salts of 2-amino-4,6-dimethylpyrimidine. This correlation differs from the correlation observed in substituted pyrimidine, where the hydrogen atoms are replaced by other atoms or functional groups. The difference is analyzed in a model, which assumes that the hydrogen bonding and substituents affect the nitrogen lone pair and ? electron orbitals. The analysis shows that the two effects are nearly independent. PMID:23675946

Seliger, Janez; Žagar, Veselko

2013-05-29

90

Decoherence in nuclear collisions: Towards a new understanding of near Coulomb barrier nuclear reactions  

SciTech Connect

To understand the underlying physical processes that might lead to loss of quantum coherence, high precision quasi-elastic excitation functions at sub-barrier energies were measured. Results show transfer events to high excitation energies, which may be impossible to model in a coherent picture. This points to the need to explicitly include quantum decoherence in nuclear reaction models and ultimately to a new understanding of near Coulomb barrier nuclear reactions.

Evers, M.; Dasgupta, M.; Hinde, D. J. [Department of Nuclear Physics, Research School of Physics and Engineering, Australian National University, Canberra, ACT 0200 (Australia)

2010-04-26

91

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

92

In-vivo study of the nuclear quadrupole interaction of99Mo (?- 99)Tc in nitrogenase of Klebsiella pneumoniaein nitrogenase of Klebsiella pneumoniae  

NASA Astrophysics Data System (ADS)

We report on the first TDPAC-measurements of the nuclear quadrupole interaction (NQI) of (NQI) of99Mo(?-)99Tc in the nitrogenase of the bacteria Klebsiella pneumoniae. Because nitrogenase is the only Mo-containing enzyme in Klebsiella pneumoniae under the chosen conditions, no further isolation of this enzyme was necessary. The majority of the incorporated99Mo is subjected to a well defined NQI with ?=365(7) Mrad/s, ?=1 and a reorientational correlation time of ?co???10nsec and is attributed to the active site of the FeMo cofactor. During sample preparation we noted a pronounced affinity of the bacteria to99mTc.

Mottner, P.; Lerf, A.; Ni, X.; Butz, T.; Erfkamp, J.; Müller, A.

1990-08-01

93

Peptide backbone orientation and dynamics in spider dragline silk and two-photon excitation in nuclear magnetic and quadrupole resonance  

NASA Astrophysics Data System (ADS)

In the first part of the dissertation, spider dragline silk is studied by solid state NMR techniques. The dependence of NMR frequency on molecular orientation is exploited using the DECODER experiment to determine the orientation of the protein backbone within the silk fibre. Practical experimental considerations require that the silk fibres be wound about a cylindrical axis perpendicular to the external magnetic field, complicating the reconstruction of the underlying orientation distribution and necess-itating the development of numerical techniques for this purpose. A two-component model of silk incorporating static b-sheets and polyglycine II helices adequately fits the NMR data and suggests that the b-sheets are well aligned along the silk axis (20 FWHM) while the helices are poorly aligned (68 FWHM). The effects of fibre strain, draw rate and hydration on orientation are measured. Measurements of the time-scale for peptide backbone motion indicate that when wet, a strain-dependent frac-tion of the poorly aligned component becomes mobile. This suggests a mechanism for the supercontraction of silk involving latent entropic springs that undergo a local strain-dependent phase transition, driving supercontraction. In the second part of this dissertation a novel method is developed for exciting NMR and nuclear quadrupole resonance (NQR) by rf irradiation at multiple frequencies that sum to (or differ by) the resonance frequency. This is fundamentally different than traditional NMR experiments where irradiation is applied on-resonance. With excitation outside the detection bandwidth, two-photon excitation allows for detection of free induction signals during excitation, completely eliminating receiver dead-time. A theoretical approach to describing two-photon excitation is developed based on average Hamiltonian theory. An intuition for two-photon excitation is gained by analogy to the coherent absorption of multiple photons requiring conservation of total energy and momentum. It is shown that two-photon excitation efficiency impro-ves when the two applied rf frequencies deviate from half-resonance. For two-photon NQR, it is shown that observable magnetization appears perpendicular to the excita-tion coil, requiring a second coil for detection, and that double quantum coherences are also generated. Several model systems and experimental geometries are used to demonstrate the peculiarities of two-photon excitation in NMR and NQR.

Eles, Philip Thomas

94

Coupling of nuclear quadrupole and octupole degrees of freedom in an angular momentum dependent potential of two deformation variables  

SciTech Connect

We propose a collective rotation-vibration Hamiltonian of nuclei in which the axial quadrupole {beta}2 and octupole {beta}3 variables are coupled through the centrifugal interaction. We consider that the system oscillates between positive and negative {beta}3-values by rounding a potential core in the ({beta}2,{beta}3)- space. We examine the effect of the 'rounding' in the structure of the spectrum.

Minkov, N.; Yotov, P.; Drenska, S. [Institute of Nuclear Research and Nuclear Energy, 72 Tzarigrad Road, 1784 Sofia (Bulgaria); Scheid, W. [Institut fuer Theoretische Physik der Justus-Liebig-Universitaet, Heinrich-Buff-Ring 16, D-35392 Giessen (Germany); Bonatsos, Dennis; Lenis, D.; Petrellis, D. [Institute of Nuclear Physics, N.C.S.R. 'Demokritos', GR-15310 Aghia Paraskevi, Attiki (Greece)

2006-04-26

95

Calculation of the nuclear quadrupole resonance spectra of YBa/sub 2/Cu/sub 3/O/sub 7/minus/x/  

SciTech Connect

Nuclear quadrupole resonance (NQR) and nuclear magnetic resonance (NMR) studies on /sup 63,65/Cu have demonstrated the the resonance properties of these nuclei can give important information about the electronic structure of the high temperature superconductor YBa/sub 2/Cu/sub 3/O/sub 7/minus/x/ as well as the exchange coupling energy between the Cu(2) sites. Measurements for various oxygen stoichiometries have given insight into the effect of oxygen content on the valence state of the Cu. In the work reported here, the electric field gradient (EFG) tensors at the Cu(1) and Cu(2) sites in YBa/sub 2/Cu/sub 3/O/sub 7/minus/x/, have been determined from calculations on large clusters for x = 0 and 1. 13 refs., 2 tabs.

Winter, N.W.; Violet, C.E.

1989-06-01

96

Temperature dependence of nonequivalent potential wells for pyridinium ion reorientation in pyridinium tetrachloroiodate(III), PyHICl4, studied by 1H-14N nuclear quadrupole double resonance.  

PubMed

The reorientation of a pyridinium ion in the paraelectric and antiferroelectric phase of PyHICl(4) is investigated using (1)H-(14)N nuclear quadrupole double resonance (NQDR). The (14)N nuclear quadrupole resonance frequencies are measured. The temperature variations of the principal values of the time-averaged electric-field-gradient (EFG) tensor at the nitrogen position are used to determine the occupation probabilities of the six orientations of a pyridinium ion in both crystallographic phases. The energy difference between various orientations is determined. The molar transition entropy associated with the reorientation of the pyridinium ions is calculated and compared to the experimental value. PMID:18470865

Seliger, J; Zagar, V; Asaji, T; Konnai, A

2008-08-01

97

A theoretical study of 17O, 14N and 2H nuclear quadrupole coupling tensors in the real crystalline structure of acetaminophen  

NASA Astrophysics Data System (ADS)

A systematic computational investigation was carried out to characterize the 17O, 14N and 2H electric field gradient, EFG, tensors in the acetaminophen real crystalline structure. To include the hydrogen bonding effects in the calculations, the most probable interacting molecules with the target molecule in the crystalline phase were considered through the various molecular clusters. The calculations were performed with the B3LYP method and 6-311++G?? and 6-311+G? standard basis sets using the Gaussian 98 suite of programs. Calculated EFG tensors were used to evaluate the 17O, 14N, and 2H nuclear quadrupole resonance, NQR, parameters in acetaminophen crystalline structure, which are in good agreement with the available experimental data. The difference between the calculated NQR parameters of the monomer and molecular clusters shows how much hydrogen bonding interactions affect the EFG tensors of each nucleus. These results indicate that both O H?O and N H?O hydrogen bonding have major influence on the NQR parameters. Moreover, the quantum chemical calculation indicated that the intermolecular hydrogen bonding interactions play an essential role in determining the relative orientation of quadrupole coupling principal components in the molecular frame axes.

Behzadi, Hadi; Esrafili, Mehdi D.; Hadipour, Nasser L.

2007-03-01

98

Decoherence in nuclear collisions: Towards a new understanding of near Coulomb barrier nuclear reactions  

Microsoft Academic Search

To understand the underlying physical processes that might lead to loss of quantum coherence, high precision quasi-elastic excitation functions at sub-barrier energies were measured. Results show transfer events to high excitation energies, which may be impossible to model in a coherent picture. This points to the need to explicitly include quantum decoherence in nuclear reaction models and ultimately to a

M. Evers; M. Dasgupta; D. J. Hinde

2010-01-01

99

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

100

Variable-pitch rectangular cross-section radiofrequency coils for the nitrogen-14 nuclear quadrupole resonance investigation of sealed medicines packets.  

PubMed

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 (14)N 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

Barras, Jamie; Katsura, Shota; Sato-Akaba, Hideo; Itozaki, Hideo; Kyriakidou, Georgia; Rowe, Michael D; Althoefer, Kaspar A; Smith, John A S

2012-10-26

101

Nodal superconductivity and non-Fermi-liquid behavior in Ce2PdIn8 studied by 115In nuclear quadrupole resonance  

NASA Astrophysics Data System (ADS)

Nuclear quadrupole resonance measurements were performed on the heavy-fermion superconductor Ce2PdIn8. Above the Kondo coherence temperature Tcoh?30 K, the spin-lattice relaxation rate 1/T1 is temperature independent, whereas at lower temperatures, down to the onset of superconductivity at Tc=0.64 K, it is nearly proportional to T1/2. Below Tc, 1/T1 shows no coherence peak and decreases as T3 down to 75 mK. All these findings indicate that Ce2PdIn8 is close to the antiferromagnetic quantum critical point, and the superconducting state has an unconventional character with line nodes in the superconducting gap.

Fukazawa, H.; Nagashima, R.; Shimatani, S.; Kohori, Y.; Kaczorowski, D.

2012-09-01

102

Rotational spectrum, nuclear quadrupole coupling constants, and structure of six isotopomers of the argon-chlorocyclobutane van der Waals complex  

NASA Astrophysics Data System (ADS)

The Fourier Transform Pulsed Jet Microwave spectra of the argon-chlorocyclobutane van der Waals complex have been assigned for six isotopomers. These include the 35Cl and 37Cl each with four 12Cs in the ring plus the four isotopomers of the 35Cl with one 13C at each position in the ring. The spectroscopic constants for the Ar-12C4H735Cl complex are A=2675.2641(6) MHz, B=977. 8306(3) MHz, C=764.9382(2) MHz; ?J=1.737(1), ?JK=7.176(6), ?K=15.28(2), ?J=0.4148(6), ?K=6.61(3) kHz; and ?aa=28.011(6) MHz, (?bb ?cc)=-80.378(6) MHz, ?ab=-22.8(1) MHz, ?ac=-5.4(7) MHz and ?bc=-26.47(9) MHz. The structure of the ground vibrational state of the complex has an equatorial chlorine as in the non-complexed ring and the argon coordinates are a=1.267 Å, b=2.824 Å and c=2.517 Å in the principal axis system of the monomer ring. The chlorine coordinate in this axis system is a=1.66, b=0.0 and c=0.08 Å. The argon is exo to the ring 2.4 Å above the C Cl bond but 2.8 Å to the side of the plane of symmetry of the chlorocyclobutane monomer. Argon is within the van der Waals radii of the nearest cross-ring methylene hydrogen and outside the van der Waals radii of chlorine. It is not directly above the ring as has been observed in other four-membered ring complexes. The off-diagonal quadrupole moment of the monomer, chlorocyclobutane, has been measured, ?ac=32.0(6) MHz. The quadrupole tensor for the chlorine in the complex was fit including all three off diagonal elements. The van der Waals bond does not significantly perturb the electronic gradients at the chlorine nucleus of the monomer, since each element of the quadrupole tensor measured for the complex, except one small off-diagonal constant, is within 3% of that projected onto the complex from chlorocyclobutane. The argon position is also consistent with the observation and intensities of a, b, and c-type rotational transitions from the projection of the monomer dipole moment onto the complex principal axis system.

Subramanian, Ranga; Szarko, Jodi M.; Pringle, Wallace C.; Novick, Stewart E.

2005-05-01

103

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

104

Weak Magnetic Order in Bilayered-Hydrate NaxCoO2\\\\cdotyH2O Structure Probed by Co Nuclear Quadrupole Resonance Proposed Phase Diagram in Superconducting NaxCoO2\\\\cdotyH2O---  

Microsoft Academic Search

A weak magnetic order was found in a nonsuperconducting bilayered-hydrate NaxCoO2\\\\cdotyH2O sample by Co nuclear quadrupole resonance (NQR) measurement. The nuclear spin-lattice relaxation rate divided by temperature 1\\/T_1T shows a prominent peak at 5.5 K, below which a Co NQR peak splits due to an internal field at the Co site. From the analyses of the Co NQR spectrum at

Yoshihiko Ihara; Kenji Ishida; Chishiro Michioka; Masaki Kato; Kazuyoshi Yoshimura; Kazunori Takada; Takayoshi Sasaki; Hiroya Sakurai; Eiji Takayama-Muromachi

2005-01-01

105

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.

106

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.

107

Electric quadrupole moment of 31Al  

NASA Astrophysics Data System (ADS)

The electric quadrupole moment Q for the ground state of 31Al (I? = 5/2+) was measured by means of the ? ray-detected nuclear quadrupole resonance. A spin-polarized radioactive beam of 31Al was produced in the projectile-fragmentation reaction of a 40Ar beam on a 93Nb target. For the Q moment measurement, we developed a new radio-frequency application system to induce the spin reversal.

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.; Murata, J.; Kawamura, H.; Narita, K.

2008-10-01

108

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.

109

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.

110

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.

111

s-wave superconductivity in superconducting BaTi2Sb2O revealed by 121/123Sb-NMR/nuclear quadrupole resonance measurements  

NASA Astrophysics Data System (ADS)

We report the 121/123Sb-NMR/nuclear quadrupole resonance (NQR) measurements on the superconductor BaTi2Sb2O with a two-dimensional Ti2O square-net layer formed with Ti3+ (3d1). NQR measurements revealed that the in-plane four-fold symmetry is broken at the Sb site below TA˜40 K, without an internal field appearing at the Sb site. These exclude a spin-density wave (SDW)/ charge density wave (CDW) ordering with incommensurate correlations, but can be understood with the commensurate CDW ordering at TA. The spin-lattice relaxation rate 1/T1, measured at the four-fold symmetry breaking site, decreases below superconducting (SC) transition temperature Tc, indicative of the microscopic coexistence of superconductivity and the CDW/SDW phase below TA. Furthermore, 1/T1 of 121Sb-NQR shows a coherence peak just below Tc and decreases exponentially at low temperatures. These results are in sharp contrast with those in cuprate and iron-based superconductors, and strongly suggest that its SC symmetry is classified to an ordinary s-wave state.

Kitagawa, S.; Ishida, K.; Nakano, K.; Yajima, T.; Kageyama, H.

2013-02-01

112

An Empirical Relationship between Optical Properties and the Nuclear Quadrupole Coupling Parameters in the Boron Sites in the Nonlinear Optical CsLiB6O10  

NASA Astrophysics Data System (ADS)

The rotation patterns of the nuclear magnetic resonance of 11B (I=3/2) in a nonlinear optical CsLiB6O10 single crystal were measured in three mutually perpendicular crystal planes. We observed sixteen different spectra which could be divided into two groups corresponding to two kinds of boron atoms, B(1) and B(2), having different boron-oxygen rings and lying at crystallographically inequivalent sites. From these results, the quadrupole coupling constants and the asymmetry parameters were determined at room temperature for the first time. For the 4-coordinated B(1), e2qQ/h=0.23± 0.03 MHz and ?=0.456± 0.004, and for the 3-coordinated B(2), e2qQ/h=2.58± 0.03 MHz and ?=0.276± 0.004. The directions of the principal axes of the electric field gradient tensors were also determined. The spectra for the two groups have different principal values of the electric field gradient tensor and originate from magnetically inequivalent sites. The principal Z-axis of the EFG tensor nearly coincides with the normal to the plane of the boron-oxygen triangle. We found an interesting correlation between the asymmetry parameter and the largest nonlinear optical coefficient.

Lim, Ae Ran; Kim, Ji Won; Yoon, Choon Sup

2003-07-01

113

Toward Understanding the Microscopic Origin of Nuclear Clustering  

SciTech Connect

Open Quantum System (OQS) description of a many-body system involves interaction of Shell Model (SM) states through the particle continuum. In realistic nuclear applications, this interaction may lead to collective phenomena in the ensemble of SM states. We claim that the nuclear clustering is an emergent, near-threshold phenomenon, which cannot be elucidated within the Closed Quantum System (CQS) framework. We approach this problem by investigating the near-threshold behavior of Exceptional Points (EPs) in the realistic Continuum Shell Model (CSM). The consequences for the alpha-clustering phenomenon are discussed.

Okolowicz, J. [Institute of Nuclear Physics, Polish Academy of Sciences; Nazarewicz, Witold [UTK/ORNL/University of Warsaw; Ploszajczak, M. [Grand Accelerateur National d'Ions Lourds (GANIL)

2013-01-01

114

New paradigm for understanding nuclear strategy. Study project  

SciTech Connect

With the end of the Cold War as we have known it since the late 1940s and the apparent success of U.S. containment policy, old, familiar questions demand answers in a new and unfamiliar context. The Cold War is over but the Nuclear Age is not; nuclear weapons cannot be disinvented. Collapse of the Warsaw Pact and dramatic reduction of tensions between the United States and the USSR compel re-examination of fundamental strategy issues. What is the purpose of nuclear weapons. How should we plan for their use. What kinds of weapons and delivery systems should we develop and deploy. How many should we have. Why have any. This essay does not seek to provide a comprehensive review of nuclear strategy since 1945, nor does it provide detailed recommendations for future strategy. Rather, it introduces a new paradigm, a new structure, a new set of lenses, which permits the strategist to seek old familiar information in a different context. Taking strategy to include ends, ways, and means, the new paradigm introduced herein interprets the past 45 years as three discernible time periods, each with a different characteristic.

Dixon, J.C.

1991-04-04

115

Quadrupole coupling constants and isomeric Mössbauer shifts for halogen-containing gold, platinum, niobium, tantalum and antimony compounds  

Microsoft Academic Search

We have analyzed by means of Density functional theory calculations the nuclear quadrupole coupling constants of a range of gold, antimony, platinum, niobium and tantalum compounds. The geometrical parameters and halogen nuclear quadrupole coupling constants obtained by these calculations substantially corresponded to the data of microwave and nuclear quadrupole resonance spectroscopy. An analysis of the quality of the calculations that

O. K. Poleshchuk; V. Branchadell; R. A. Ritter; A. V. Fateev

2008-01-01

116

The Role of Nuclear Physics in Understanding the Cosmos and the Origin of Elements  

NASA Astrophysics Data System (ADS)

This popular lecture, given in the conference celebrating contributions of Akito Arima to physics on the occasion of his 80th anniversary, outlines the role of nuclear physics in understanding the origin of elements.

Balantekin, A. B.

2011-05-01

117

The Role of Nuclear Physics in Understanding the Cosmos and the Origin of Elements  

SciTech Connect

This popular lecture, given in the conference celebrating contributions of Akito Arima to physics on the occasion of his 80th anniversary, outlines the role of nuclear physics in understanding the origin of elements.

Balantekin, A. B. [Physics Department, University of Wisconsin, Madison WI 53706 (United States)

2011-05-06

118

Understanding radiologic and nuclear terrorism as public health threats: preparedness and response perspectives.  

PubMed

Terrorism dates back to antiquity, but our understanding of it as a public health threat is still in its nascent stages. Focusing on radiation and nuclear terrorism, we apply a public health perspective to explore relevant physical health and psychosocial impacts, the evolving national response infrastructure created to address terrorism, and the potential roles of nuclear medicine professionals in preparing for and responding to radiologic and nuclear terrorism. PMID:17015902

Barnett, Daniel J; Parker, Cindy L; Blodgett, David W; Wierzba, Rachel K; Links, Jonathan M

2006-10-01

119

Super hybrid quadrupoles  

NASA Astrophysics Data System (ADS)

A new model of quadrupole composed of permanent magnetic material, coils and soft magnetic material is proposed for the new Brazilian Synchrotron Light Source (Sirius). These quadrupoles must have flexibility about 30% of the total gradient in order to correct the linear effects caused by the insertion devices on the beam dynamics. This flexibility is obtained using coils while permanent magnets are used to supply the constant gradient.

Tosin, Giancarlo; Palma Sanchez, Priscila; Citadini, James Francisco; Castro Vergasta, Camila

2012-05-01

120

Radiation resistant HTS quadrupoles for RIA  

Microsoft Academic Search

Extremely high radiation, levels with accumulated doses comparable to those in nuclear reactors than in accelerators, and very high heat loads (?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

R. Gupta; M. Anerella; M. Harrison; W. Sainpson; J. Schmalzle; R. Ronningen; A. Zeller

2005-01-01

121

The effects of H-bonding, change of state and molecular distortion on 2H and 17O nuclear quadrupole coupling constants: general theoretical considerations and specific application to formic acid  

NASA Astrophysics Data System (ADS)

The major emphasis here is in analysing the effect of H-bonding on the nuclear quadrupole coupling behaviour of 2H and 17O nuclei. Using ab initio quantum mechanical methods on the test molecule formic acid, the coupling amplitudes (nuclear quadrupole coupling constants e2qQ/h) and, also, coupling anisotropies (asymmetry parameter ?) and orientations of the electric field gradient principal axis system with respect to molecular axes have been calculated. As formic acid contains 2H and 17O nuclei in a variety of functional groups — alkyl ( 2H), hydroxyl ( 2H and 17O) and carboxyl ( 17O) — it is a particularly efficient molecule for theoretical study. In addition the structures of its H-bonded complexes vary as a function of phase from the cyclic H-bonded gaseous dimer through a probably chain-like association in the liquid to a regular chain H-bonded solid phase. Thus in this work the consequences of differing H-bond geometries on nuclear quadrupole coupling of the given nuclei are investigated, and also the relative contributions to the coupling changes of geometric and electronic disortions resulting from H-bonding and lattice field effects in the solid, are evaluated. The theoretical results are compared with the most up-to-date experimental data available. General problems in calculating molecular electric field gradients are outlined and, in particular, errors resulting from uncertainties in experimental input geometries are critically assessed. Differences in computational emphasis for 2H as compared with 17O and other "heavy" nuclei are pointed out.

Gready, Jill E.

1981-02-01

122

Comparison of the effects of symmetric versus asymmetric H bonding on 2H and 17O nuclear quadrupole coupling constants: Application to formic acid and the hydrogen diformate anion  

NASA Astrophysics Data System (ADS)

In this paper, we analyse the effects on the nuclear quadrupole coupling behaviour of 2H and 17O nuclei of a shift in H-bond character from asymmetric to symmetric. Using ab initio methods, the coupling amplitudes (nuclear quadrupole coupling constant e2qQ/h ) coupling anisotropies (asymmetry parameter ?), and orientations of the electric field gradient (EFG) principal axis (PA) system of the H-bonded deuterium and oxygen nuclei in the formic acid dimer and related monomers, and the deuterium diformate anion are calculated. In addition, the relative contributions to the 2H and 17O EFGs of nuclear and electronic terms, and also the convergence of the EFG as a function of contributions from increasingly distant nuclei in the molecule are investigated. The trends in the calculated 17O EFGs on going from an asymmetric to a symmetric H-bonded environment are correlated with experimental nqr data in order to establish the hitherto unknown e2qQ/h sign, EFG assignments and PA orientation of symmetrically H-bonded oxygen. The possibility that the e2qQ/h value of deuterium is negative for symmetric H bonds is discussed, and difficulties in the computation of 2H EFGs for symmetric - as distinct from asymmetric - H-bonded systems are pointed out. In strong disagreement with assumptions in the literature, it is found that nearest neighbour terms do not dominate the 2H EFG in symmetrically H-bonded systems.

Gready, Jill E.; Backsay, G. B.; Hush, N. S.

1982-01-01

123

Nuclear quadrupole moment of scandium  

Microsoft Academic Search

The multiconfiguration Dirac-Fock model is employed to evaluate the effects of relativity and electron correlation on the hyperfine interaction constants of the 3d2 3F3, 3F4, 1G4, and 3d4p 3F4 levels of Sc II. The wave function expansions are obtained with the active space method, where configuration state functions of a specific parity and J value are generated by substitutions from

Jacek Bieron; Ian P. Grant; Charlotte Froese Fischer

1997-01-01

124

Nuclear deformations in the pairing-plus-quadrupole model (V). Energy levels and electromagnetic moments of the W, Os and Pt nuclei  

Microsoft Academic Search

The low-lying even-parity energy levels and wave functions of the even isotopes of tungsten, osmium and platinum are calculated within the framework of Bohr's collective Hamiltonian. The six kinetic energy functions and the potential energy function which enter the Hamiltonian, and which determine the coupling between rotational motion, beta-vibrations and gamma-vibrations, are derived microscopically by using the pairing-plus-quadrupole model of

Krishna Kumar; Michel Baranger

1968-01-01

125

QUADRUPOLE CORRELATIONS IN LIGHT NUCLEI  

Microsoft Academic Search

Interactions leading to quadrupole correlations of alpha -particle ; type nuclei are investigated. Certain regularities in the bond energies of ; nucleons in light nuclei are analyzed by the shell model, with considerations for ; pair and quadrupole correlations. The quadrupole correlations disappear with ; neutron numbers exceeding the number of protons, explaining the variation in ; alpha -particle property

Solovev

1960-01-01

126

Quadrupole collectivity in the two-body random ensemble  

SciTech Connect

We conduct a systematic investigation of the nuclear collective dynamics that emerges in systems with two-body random interactions. We explore the development of the mean field and study its geometry. We investigate multipole collectivities in the many-body spectra and their dependence on the underlying two-body interaction Hamiltonian. The quadrupole-quadrupole interaction component appears to be dynamically dominating in the two-body random ensemble. This quadrupole coherence leads to rotational spectral features and thus suggests the formation of the deformed mean-field of a specific geometry.

Abramkina, Volha; Volya, Alexander [Department of Physics, Florida State University, Tallahassee, Florida 32306-4350 (United States)

2011-08-15

127

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

128

Description of nuclear octupole and quadrupole deformation close to axial symmetry: Octupole vibrations in the X(5) nuclei {sup 150}Nd and {sup 152}Sm  

SciTech Connect

The model, introduced in a previous paper, for the description of the octupole and quadrupole degrees of freedom in conditions close to the axial symmetry is used to describe the negative-parity band based on the first octupole vibrational state in nuclei close to the critical point of the U(5)-to-SU(3) phase transition. The situation of {sup 150}Nd and {sup 152}Sm is discussed in detail. The positive-parity levels of these nuclei, and also the in-band E2 transitions, are reasonably accounted for by the X(5) model. With simple assumptions on the nature of the octupole vibrations, it is also possible to describe the negative-parity sector with comparable accuracy without changing the description of the positive-parity part.

Bizzeti, P. G.; Bizzeti-Sona, A. M. [Dipartimento di Fisica, Universita di Firenze, Istituto Nazionale di Fisica Nucleare, Sezione di Firenze, Via G. Sansone 1, I-50019 Sesto Fiorentino (Firenze) (Italy)

2010-03-15

129

Quadrupole coupling constants and isomeric Mössbauer shifts for halogen-containing gold, platinum, niobium, tantalum and antimony compounds  

Microsoft Academic Search

We have analyzed by means of Density functional theory calculations the nuclear quadrupole coupling constants of a range of\\u000a gold, antimony, platinum, niobium and tantalum compounds. The geometrical parameters and halogen nuclear quadrupole coupling\\u000a constants obtained by these calculations substantially corresponded to the data of microwave and nuclear quadrupole resonance\\u000a spectroscopy. An analysis of the quality of the calculations that

O. K. Poleshchuk; V. Branchadell; R. A. Ritter; A. V. Fateev

2008-01-01

130

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

131

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.

132

Deuteron quadrupole coupling in hydrogen bonded systems. IV. Deuteron quadrupole coupling in substituted phenols  

Microsoft Academic Search

The pure nuclear quadrupole spectrum of deuterium at oxygen in chlorinated phenols has been observed by level crossing double resonance with the ring protons. Observed coupling constants, ranging from 200 to 250 kHz, exhibit the effects of strong hydrogen bonding through their correlation with the intermolecular O–H???O bond lengths in those cases where structure data are available. This is interpreted

L. S. Batchelder; J. Clymer; J. L. Ragle

1981-01-01

133

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

134

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

Microsoft Academic Search

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

M. T. Peters; R. C. Ewing

2007-01-01

135

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

Microsoft Academic Search

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

M. T. Peters; R. C. Ewing

2006-01-01

136

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 break-down 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 trade-offs between very large numbers of small channels and a smaller number of large channels, and the dependence of the choice on the voltage break-down 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). Accelerator and Fusion Research Div.

1996-03-01

137

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

138

Optical determination of the quadrupole moment of 138La  

Microsoft Academic Search

The rare lanthanum isotope 138La was highly enriched with the aid of an electromagnetic isotope separator. The hyperfine structure of two La-lines has been investigated by means of optical interference spectroscopy which allowed the determination of the nuclear electric quadrupole moment Q(138La) = 0.51 +\\/- 0.09b.

W. Fischer; H. Hühnermann; K. Mandrek; H. Ihle

1972-01-01

139

62 FR 11936 - Notice of Availability of Memorandum of Understanding Between the Nuclear Regulatory Commission...  

Federal Register 2010, 2011, 2012, 2013

...Between the Department of Energy and the Nuclear Regulatory Commission...Introduction The Department of Energy (DOE) and the Nuclear Regulatory Commission...regulated by NRC under the Energy Reorganization Act of 1974, the Nuclear Waste Policy Act...

1997-03-13

140

62 FR 59910 - Memorandum of Understanding Between the Nuclear Regulatory Commission and the Department of...  

Federal Register 2010, 2011, 2012, 2013

...the Department of Energy...SUMMARY: The Nuclear Regulatory Commission...the Department of Energy and the Nuclear Regulatory Commission...between Department of Energy Regulatory Oversight Manager and Nuclear Regulatory...

1997-11-05

141

64 FR 3986 - Final Memorandum of Understanding Between the Nuclear Regulatory Commission and the Department of...  

Federal Register 2010, 2011, 2012, 2013

...Commission and the Department of Energy agency: Nuclear Regulatory Commission. action...Commission and the Department of Energy Governing Nuclear Regulatory Commission Funded...between the Department of Energy and the Nuclear Regulatory Commission...

1999-01-26

142

Combined Panofsky Quadrupole & Corrector Dipole  

SciTech Connect

Two styles of Panofsky Quadrupoles with integral corrector dipole windings are in use in the electron beam line of the Free Electron Laser at Jefferson Lab. We combined steering and focusing functions into single magnets, adding hundreds of Gauss-cm dipole corrector capability to existing quadrupoles because space is at a premium along the beam line. Superposing a one part in 100 dipole corrector field on a 1 part in 1000, weak (600 to 1000 Gauss) quadrupole is possible because the parallel slab iron yoke of the Panofsky Quadrupole acts as a window frame style dipole yoke. The dipole field is formed when two electrically floating “current sources”, designed and made at JLab, add and subtract current from the two opposite quadrupole current sheet windings parallel to the dipole field direction. The current sources also drive auxiliary coils at the yoke’s inner corners that improve the dipole field. Magnet measurements yielded the control system field maps that characterize the two types of fields. Field analysis using TOSCA, construction and wiring details, magnet measurements and reference for the current source are presented.

George Biallas; Nathan Belcher; David Douglas; Tommy Hiatt; Kevin Jordan

2007-07-02

143

33S NMR spectroscopy. 4. Substituent effects on the 33S nuclear quadrupole coupling constants and electric field gradient in 3- and 4-substituted benzenesulphonates studied by DFT calculations in vacuo and in aqueous solution  

NASA Astrophysics Data System (ADS)

33S nuclear quadrupole coupling constants (?) and the principal component of the electric field gradient (qzz) in 3- and 4-substituted benzenesulphonates are dependent on the electronic properties of substituents. Previously reported experimental results were interpreted with the support of theoretical calculations in vacuo and in aqueous solution. To obtain good reproducibility of the experimental data, the introduction of the solvent effect into the calculations was mandatory. The best results were obtained at the B3LYP/6-311++G(3d,p) level using the Integral Equation Formalism for the Polarisable Continuum Model (IEF-PCM) to reproduce the solvent effect. In vacuo, for neutral substituents, the substituent effect on sulphur qzz can be mainly ascribed to electronic interactions (i.e., inductive and mesomeric effects transmitted through the aromatic ring). For charged substituents (3-NH3+,4-NH3+,4-NH(CH)2+,3-SO3-,4-SO3-,3-O,4-O) there is also a relevant contribution of coulomb origin, owed to the electric charge on the substituent itself, which polarises the S-O and C-S bonds. In aqueous solution, short-range solute-solvent interactions (i.e., hydrogen bonding) can be neglected, and the solvent effect can be adequately described considering the electrostatic interactions between the C-SO3- moiety and the electric charges on the surface of the cavity embedding the molecule within the solvent. These interactions amplify the electronic contribution transmitted through the aromatic ring and partially annihilate the coulomb contribution of the intrinsic charges of substituents. The results of the Natural Bond Orbital (NBO) analysis support these results and demonstrate that the polarisation of the S-O and S-C bonds and oxygen lone pairs due to solvent interactions produces only a redistribution of the electron density around the sulphur nucleus, thus inducing the variations of qzz.

Musio, Roberta; Sciacovelli, Oronzo

2013-11-01

144

The role of ANS in enhancing public understanding of advanced nuclear energy plants  

Microsoft Academic Search

Concurrent with the design certification of both evolutionary and passive designs for advanced nuclear energy plants in the US, the American Nuclear Society (ANS) has an extensive nuclear community and public information program under way. The goal of the program is to inform both the technical community and the general public on the following major topics related to the deployment

E. L. Quinn; K. H. Turner

1992-01-01

145

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

146

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

147

Quadrupole mode perturbation in storage rings  

Microsoft Academic Search

Quadrupole mode oscillation (QMO) means the second moments of a system oscillating with time, or, the elliptical torus of the Hamiltonian rotating in phase space. We study the QMO in storage rings. In the transverse direction the QMO can be excited by an rf quadrupole. The strength of the rf quadrupole varies with time, and the oscillation frequency om must

Weiming Guo

2003-01-01

148

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

149

Nuclear quadrupole resonance of amidinium tetrachlorophosphorates  

SciTech Connect

The /sup 35/Cl NQR spectra and relaxation parameters of the cyclic amidinium tetrachlorophosphorates PCl/sub 4/(NCH/sub 3/)/sub 2/CX, where X = C/sub 6/H/sub 5/ (1), CCl/sub 3/ (2), and CF/sub 3/ (3), have been studied at 77/sup 0/K. The crystal of (3) has been found to contain two coexisting phases of the compound, which consist, respectively, and zwitterionic molecules of a hexacoordinated phosphorus atom with square-pyramidal symmetry of the PCl/sub 4/ group and molecules of chlorotropic isomers with a trigonal-bipyramidal environment for the phosphorus atom. The structural features of the crystalline state and the nature of the phosphorus-ligand bonds have been discussed.

Romanenko, E.A.; Kal'chenko, V.I.; Rudyi, R.B.

1986-05-01

150

Remote sensing by nuclear quadrupole resonance  

Microsoft Academic Search

Detection of explosives has the flavor of those mathematical problems that are not invertible. It is easier to hide explosives than to find them. Many approaches have been proposed and executed for the remote detection of explosives, contraband materials, weapons of mass destruction, currency, etc. Most detection technologies suffer from a common problem: the features they look for, such as

Allen N. Garroway; Michael L. Buess; Joel B. Miller; Bryan H. Suits; Andrew D. Hibbs; Geoffrey A. Barrall; Robert Matthews; Lowell J. Burnett

2001-01-01

151

General quadrupole shapes in the Interacting Boson Model  

SciTech Connect

Characteristic attributes of nuclear quadrupole shapes are investigated within the algebraic framework of the Interacting Boson Model. For each shape the Hamiltonian is resolved into intrinsic and collective parts, normal modes are identified and intrinsic states are constructed and used to estimate transition matrix elements. Special emphasis is paid to new features (e.g. rigid triaxiality and coexisting deformed shapes) that emerge in the presence of the three-body interactions. 27 refs.

Leviatan, A.

1990-01-01

152

Magnetic-Resonance Relaxation and Saturation of Quadrupole-Interacting Spin System  

Microsoft Academic Search

A system of equations describing spin-lattice relaxation, saturation, and cross relaxation of a quadrupole-interacting spin system is derived from the Liouville equation by combining the orthogonal-operator-expansion method with energy-level population operators. The theory is applied to quadrupole-perturbed nuclear magnetic resonance where spin-lattice relaxation and saturation coefficients are calculated. There is a difference between the dipolar spinlattice relaxation rates of systems

J. Stepisnik

1973-01-01

153

Sign-Selected Quadrupole Train  

SciTech Connect

The design of the Sign-Selected Quadrupole Train for E-815 (NuTeV) is set forth. The relevant physics requirements are explained. The optics of the beam are presented, along with an explanation of the proton dumping scheme. A discussion of rates and backgrounds follows, with special care given to backgrounds from scraping and obstructions. The relevant tolerances for beam construction are given and justified by simulations of the beamline. This leads to a discussion of the beam monitoring.

Bernstein, R.; NuTeV Collaboration

1994-05-03

154

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 (T1/2 = 17.5 h)and 3/2+ 195Au(T1/2=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) × 1017 V/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.

1993-09-01

155

Distal and proximal ligand interactions in heme proteins: Correlations between C-O and Fe-C vibrational frequencies, oxygen-17 and carbon-13 nuclear magnetic resonance chemical shifts, and oxygen-17 nuclear quadrupole coupling constants in C sup 17 O- and sup 13 CO-labeled species  

SciTech Connect

The authors have obtained the oxygen-17 nuclear magnetic resonance (NMR) spectra of a variety of C{sup 17}O-labeled heme proteins, including sperm whale (Physeter catodon) myoglobin, two synthetic sperm whale myoglobin mutants (His E7 {yields} Val E7; His E7 {yields} Phe E7), adult human hemoglobin, rabbit (Oryctolagus cuniculus) hemoglobin, horseradish (Cochlearia armoracia) peroxidase isoenzymes A and C, and Caldariomyces fumago chloroperoxidase, in some cases as a function of pH, and have determined their isotropic {sup 17}O NMR chemical shifts, {delta}{sub i}, and spin-lattice relaxation times, T{sub 1}. They have also obtained similar results on a picket fence prophyrin. The results show an excellent correlation between the infrared C-O vibrational frequencies, {nu}(C-O), and {delta}{sub i}, between {nu}(C-O) and the {sup 17}O nuclear quadrupole coupling constant, and as expected between e{sup 2}qQ/h and {delta}{sub i}. The results suggest the IR and NMR measurements reflect the same interaction, which is thought to be primarily the degree of {pi}-back-bonding from Fe d to CO {pi}* orbitals, as outlined previously.

Ki Deok Park; Guo, K.; Adebodun, F.; Chiu, M.L.; Sligar, S.G.; Oldfield, E. (Univ. of Illinois, Urbana (United States))

1991-03-05

156

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 U6+-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 105 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

157

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.

M.T. Peters; R.C. Ewing

2006-06-22

158

Quadrupole coupling and crystal-field shielding in CaF2:Eu3+:O2- under hydrostatic pressure  

Microsoft Academic Search

The nuclear quadrupole interactions in the 7F0 ground electronic state and the 5D0 excited state of the 151Eu3+ and 153Eu3+ ions have been investigated by optical means. The optically detected nuclear quadrupole resonance, excitation, and luminescence of the Eu3+-O2- C3v symmetry center have been studied at 4.2 K in single crystals of CaF2:Eu:O under hydrostatic pressure up to 7.5 kbar.

Andrzej P. Radlinski; A. J. Silversmith

1986-01-01

159

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

160

Research on Plants for the Understanding of Diseases of Nuclear and Mitochondrial Origin  

PubMed Central

Different model organisms, such as Escherichia coli, Saccharomyces cerevisiae, Caenorhabditis elegans, Drosophila melanogaster, mouse, cultured human cell lines, among others, were used to study the mechanisms of several human diseases. Since human genes and proteins have been structurally and functionally conserved in plant organisms, the use of plants, especially Arabidopsis thaliana, as a model system to relate molecular defects to clinical disorders has recently increased. Here, we briefly review our current knowledge of human diseases of nuclear and mitochondrial origin and summarize the experimental findings of plant homologs implicated in each process.

Spampinato, Claudia P.; Gomez-Casati, Diego F.

2012-01-01

161

Understanding ploidy complex and geographic origin of the Buchloe dactyloides genome using cytoplasmic and nuclear marker systems.  

PubMed

Characterizing and inferring the buffalograss [Buchloe dactyloides (Nutt.) Engelm.] genome organization and its relationship to geographic distribution are among the purposes of the buffalograss breeding and genetics program. This buffalograss study was initiated to: (1) better understand the buffalograss ploidy complex using various marker systems representing nuclear and organelle genomes; (2) determine whether the geographic distribution was related to nuclear and organelle genome variation; and (3) compare the genetic structure of accessions with different ploidy levels. The 20 buffalograss genotypes (15 individuals from each genotype) that were studied included diploid, tetraploid, pentaploid, and hexaploid using nuclear (intersimple sequence repeat (ISSRs), simple sequence repeat (SSRs), sequence related amplified polymorphism (SRAPs), and random amplified polymorphic DNA (RAPDs)) and cytoplasmic markers (mtDNA and cpDNA). There was a significant correlation between the ploidy levels and number of alleles detected using nuclear DNA (ISSR, SSR, and SRAP, r = 0.39, 0.39, and 0.41, P<0.05, respectively), but no significant correlation was detected when mitochondrial (r = 0.17, P<0.05) and chloroplast (r = 0.11, P < 0.05) DNA data sets were used. The geographic distribution of buffalograss was not correlated with nuclear and organelle genome variation for the genotypes studied. Among the total populations sampled, regression analysis indicated that geographic distance could not explain genetic differences between accessions. However, genetic distances of those populations from the southern portion of buffalograss adaptation were significantly correlated with geographic distance (r= 0.48, P<0.05). This result supports the hypothesis that genetic relationship among buffalograss populations cannot be estimated based only on geographic proximity. PMID:16208501

Budak, H; Shearman, R C; Gulsen, O; Dweikat, I

2005-11-10

162

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

163

FIELD CHARACTERIZATION OF XFEL QUADRUPOLE MAGNETS  

Microsoft Academic Search

A rotating coil setup for magnetic field characterization and fiducialization of XFEL quadrupole magnets is pre- sented. The instrument allows measurement of the rel- ative position of the magnetic axis with accuracy better than 1 ?m and measurement of weak magnetic error field components. Tests and evaluation based on a FLASH quadrupole magnet are presented together with a discus- sion

A. Hedqvist; H. Danared; F. Hellberg; J. Pfluger

164

Beta function measurement in the Tevatron using quadrupole gradient modulation  

SciTech Connect

Early in Run2, there was an effort to compare the different emittance measurements in the Tevatron (flying wires and synchrotron light) and understand the origin of the observed differences. To measure the beta function at a few key locations near the instruments, air-core quadrupoles were installed. By modulating the gradient of these magnets and measuring the effect on the tune, the lattice parameters can be extracted. Initially, the results seem to disagree with other methods. At the time, the lattice was strongly coupled due to a skew component in the main dipoles, caused by sagging of the cryostat. After a large fraction of the superconducting magnets were shimmed to remove a strong skew quadrupole component, the results now agree with the theoretical values to within 20%.

Jansson, A.; Lebrun, P.; Volk, J.T.; /Fermilab

2005-05-01

165

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

166

Understanding the Roles of Nuclear A- and B-type Lamins in Brain Development*  

PubMed Central

The nuclear lamina is composed mainly of lamins A and C (A-type lamins) and lamins B1 and B2 (B-type lamins). Dogma has held that lamins B1 and B2 play unique and essential roles in the nucleus of every eukaryotic cell. Recent studies have raised doubts about that view but have uncovered crucial roles for lamins B1 and B2 in neuronal migration during the development of the brain. The relevance of lamins A and C in the brain remains unclear, but it is intriguing that prelamin A expression in the brain is low and is regulated by miR-9, a brain-specific microRNA.

Young, Stephen G.; Jung, Hea-Jin; Coffinier, Catherine; Fong, Loren G.

2012-01-01

167

Nuclear, biological, and chemical terrorism: understanding the threat and designing responses.  

PubMed

Today nuclear, biological, and chemical (NBC) terrorism is a serious issue. The threat of terrorist or rogue states acquiring and using NBC weapons has ushered in a new age of terrorism; an age that is far more dangerous than any previous period. It is an age of terrorism with which no one yet knows how to deal. This article reviews recent trends in terrorism, and identifies groups that have both the potential and the motive to use weapons of mass destruction. In addition, it discusses the design and implemention of effective measures to meet this threat, as well as the role of CISM teams in preparation for, and in the aftermath of, an incident involving NBC weapons. PMID:11227745

Simon, J D

1999-01-01

168

Mechanistic understanding of irradiation-induced corrosion of zirconium alloys in nuclear power plants: Stimuli, status, and outlook  

SciTech Connect

Failures in the basic materials used in nuclear power plants continue to be costly and insidious, despite increasing industry vigilance to catch failures before they degrade safety. For instance, the overall costs to the US industry from materials problems could amount to as much as $10 billion annually. Moreover, estimates indicate that the cost of a pipe failure in a nuclear plant is one hundred times greater than the cost of a similar failure in a coal-fired plant. There are important practical stimuli and much scope for further understanding of the effects of irradiation on Zr-alloys (and other materials used in nuclear installations) by careful experimentation. Moreover, these studies need to address the effect of irradiation on all components of heterogeneous systems: the metal, the oxide and the environment, and especially those processes recurring at the interphases between these components. The present paper is aimed at providing specialists with some systematic information on the subject and with important considerations on the key items for further experimentation.

Johnson, A.B. Jr.; Ishigure, K.; Nechaev, A.F.; Reznichenko, E.A.; Cox, B.; Lemaignan, C.; Petrik, N.G.

1990-05-01

169

Chromatic effects in quadrupole scan emittance measurements  

NASA Astrophysics Data System (ADS)

A reliable transverse emittance measurement for high-brightness electron beams is of utmost importance for the successful development of fourth generation light sources and for the beam transport in plasma-based accelerators. When the beam exhibits a significant energy spread, typical quadrupole scan emittance measurements may be affected depending on the beam properties and on the quadrupoles arrangement. The emittance degradation induced by chromatic effects in measurements involving magnetic lattices is evaluated analytically for different configurations. Analytical and numerical calculations compared with measurements have been used to evaluate the consequent error on the emittance value measured for single and double quadrupole schemes and for typical operating conditions at the SPARC facility.

Mostacci, A.; Bellaveglia, M.; Chiadroni, E.; Cianchi, A.; Ferrario, M.; Filippetto, D.; Gatti, G.; Ronsivalle, C.

2012-08-01

170

A novel tandem quadrupole mass analyzer  

Microsoft Academic Search

A new “tandem mass analyzer” is described. Two quadrupole mass filters are operated in series. Each is operated at low resolution\\u000a and a small mass offset is introduced between the two quadrupoles so that the pair operate together to give higher resolution.\\u000a The resolution of the tandem analyzer can be changed by changing the mass offset. The transmission is highest

Zhaohui Du; D. J. Douglas

1999-01-01

171

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. 10 figs.

Tatchyn, R.O.

1997-01-21

172

Harmonic analysis of Fermilab main ring quadrupoles  

SciTech Connect

The Main Ring Quadrupoles have been used in the Fermilab Main Ring and will be utilized in the proposed Fermilab Main Injector. Utilizing a rotating coil harmonic measurement system, a sample of more than 35 Fermilab Main Ring Quadrupoles have been measured. The asymmetric design of these magnets provides many easily measured harmonic coefficients. Results for harmonic coefficients at various excitation levels are presented. 5 refs., 3 figs., 1 tab.

Brown, B.C.; Mazur, P.O.; Ostiguy, J.F.; Pruss, S.M.; Turkot, F.

1991-05-01

173

Quadrupole deformation of barium isotopes  

NASA Astrophysics Data System (ADS)

The B(E2:01+-->21+) values of the Ba isotopes (Z=56) exhibit a sharp increase in deformation as the neutron numbers approach the mid-shell value of N=66. This behavior is anomalous because the 2+1 level energies are very similar to those of the neighboring isotopes. By means of the axially-symmetric deformed Woods-Saxon (WS) hamiltonian plus the BCS method, we investigated the systematics of B(E2) of the Ba isotopes. We showed that 15% of the B(E2) values at N=66 was due to the level crossing, occurring at the deformation ?WS~0.3, between the proton orbits originating from the orbits ??=1/2-(h11/2) and 9/2+(g9/2) at zero deformation. The latter of these two was an intruder orbit originating from below the energy gap at Z=50, rising higher in energy with the deformation and intruding the Z=50-82 shell. These two orbits have the largest magnitude of the quadrupole moment with a different sign among the orbits near and below the Fermi surface. Occupancy and non-occupancy of these orbits by protons thus affect B(E2:01+-->21+) significantly.

Sugita, Michiaki; Uchiyama, Koji; Furuno, Kohei

1998-11-01

174

Static Quadrupole Moment of the First Excited State of exp 198 Hg.  

National Technical Information Service (NTIS)

The first direct evidence of oblate nuclear deformation in the even-A mercury isotopes has been obtained by measurement of the static quadrupole moment of the first excited state of exp 198 Hg using the reorientation effect in Coulomb excitation. (Atomind...

M. T. Esat D. C. Kean R. H. Spear M. P. Fewell A. M. Baxter

1977-01-01

175

Laced permanent magnet quadrupole drift tube magnets  

SciTech Connect

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 an asymmetrical saturation curve. Since the polarity of the quadrupole magnets in a drift tube linac is not reversed we can take advantage of this asymmetrical saturation to provide greater focusing strength. The magnet configuration has been optimized and the vanadium permendur poles needed in a conventional quadrupole have been replaced with iron poles. The use of permanent magnet material has allowed us to increase the focusing strength of the magnet by about 20% over that of a conventional tape-wound quadrupole. Comparisons will be made between this magnet and the conventional tape-wound quadrupole. 3 refs., 5 figs.

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

1988-10-01

176

Measurements of spin, magnetic moment, and electric quadrupole moment of 41. 5 h /sup 188/Ir  

SciTech Connect

The techniques of nuclear orientation and nuclear magnetic resonance on oriented nuclei were applied to /sup 188/Ir after recoil implantation into Fe and Ni. Combining the results of nuclear orientation and nuclear magnetic resonance on oriented nuclei, which are sensitive to the magnetic moment and the g factor, respectively, the spin of /sup 188/Ir was determined to be I = 1, in contradiction to I = 2 adopted previously. In addition, the splitting of the nuclear magnetic resonance on oriented nuclei resonance into two subresonances due to quadrupole interaction was observed, which proves again I = 1.

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

1985-08-01

177

Influence of valence neutron configuration on quadrupole deformation in doubly-odd 134Pr  

NASA Astrophysics Data System (ADS)

Lifetimes of levels in two doubly-decoupled bands of 134Pr involving neutron intruder orbits have been measured using Doppler-shift techniques. The deduced transition quadrupole moments are consistent with total Routhian surface predictions for the suggested configurations of both bands. The negative-parity band with one neutron in the i13/2 orbit has a much larger quadrupole deformation than the positive-parity band with a neutron in the (f7/2/h9/2) orbit, reflecting the strong polarizing effect of the N=6 intruder orbit on the nuclear shape.

Rao, M. N.; Ribas, R. V.; Medina, N. H.; Oliveira, J. R.; Rizzutto, M. A.; Seale, W. A.; Petrache, C. M.; Bazzacco, D.; Lunardi, S.; Rossi Alvarez, C.; Scanferla, T.; Ur, C. A.; Venturelli, R.; Espinoza-Quiñones, F. R.; Podolyák, Zs.; de Acuña, D.; de Angelis, G.; de Poli, M.; Farnea, E.; Gadea, A.; Napoli, D. R.; Zhu, L. H.; Dewald, A.; Gableske, J.; von Brentano, P.

1998-09-01

178

Collective states of odd nuclei in a model with quadrupole-octupole degrees of freedom  

SciTech Connect

We apply the collective axial quadrupole-octupole Hamiltonian to describe the rotation-vibration motion of odd nuclei with Coriolis coupling between the even-even core and the unpaired nucleon.We consider that the core oscillates coherently with respect to the quadrupole and octupole axialdeformation variables. The coupling between the core and the unpaired nucleon provides a split paritydoublet structure of the spectrum. The formalism successfully reproduces the parity-doublet splitting in a wide range of odd-A nuclei. It provides model estimations for the third angular-momentum projection K on the intrinsic symmetry axis and the related intrinsic nuclear structure.

Minkov, N., E-mail: nminkov@inrne.bas.bg; Drenska, S. B.; Yotov, P. [Bulgarian Academy of Sciences, Institute for Nuclear Research and Nuclear Energy (Bulgaria); Bonatsos, D. [NCSR Demokritos, Institute of Nuclear Physics (Greece)], E-mail: bonat@inp.demokritos.gr; Scheid, W. [Institut fuer Theoretische Physik der Justus-Liebig-Universitaet (Germany)], E-mail: Werner.Scheid@theo.physik.uni-giessen.de

2007-08-15

179

Model Independent Determination of Quadrupole Deformation Parameters from Coulomb Excitation Measurements  

NASA Astrophysics Data System (ADS)

A relationship between experimental E2 matrix elements and nuclear quadrupole charge deformation and triaxiality is presented. Examples of experimentally determined deformation and triaxiality parameters in various regions of the nuclear chart are specified. The most interesting results were found among transitional nuclei. The first such result from a radioactive beam facility is the identification of a triaxial strongly-deformed low-lying 02^ + level in 76Kr.

Srebrny, Julian; Cline, Douglas

180

Deuteron magnetic quadrupole moment from chiral effective field theory  

NASA Astrophysics Data System (ADS)

We calculate the magnetic quadrupole moment (MQM) of the deuteron at leading order in the systematic expansion provided by chiral effective field theory. We take into account parity (P) and time-reversal (T) violation which, at the quark-gluon level, results from the QCD vacuum angle and dimension-six operators that originate from physics beyond the Standard Model. We show that the deuteron MQM can be expressed in terms of five low-energy constants that appear in the P- and T-violating nuclear potential and electromagnetic current, four of which also contribute to the electric dipole moments of light nuclei. We conclude that the deuteron MQM has an enhanced sensitivity to the QCD vacuum angle and that its measurement would be complementary to the proposed measurements of light-nuclear EDMs.

Liu, C.-P.; de Vries, J.; Mereghetti, E.; Timmermans, R. G. E.; van Kolck, U.

2012-07-01

181

A 14N nuclear quadrupole resonance study of phase transitions and molecular dynamics in hydrogen bonded organic antiferroelectrics 55DMBP-H2ca and 1,5-NPD-H2ca.  

PubMed

The temperature dependence of the (14)N NQR frequencies has been measured in antiferroelectric and paraelectric 55DMBP-H(2)ca and 1,5-NPD-H(2)ca. In both compounds we observe two non-equivalent nitrogen positions (N(+)-H···O(-) and N···H-O) in the antiferroelectric phase. The two nitrogen positions become equivalent (N···H···O) in the paraelectric phase. The critical exponent of the local antiferroelectric order parameter has been determined from the NQR data. The principal values of the quadrupole coupling tensor correlate in both compounds. The correlation diagrams clearly show how a proton migrates from the antiferroelectric position towards the paraelectric position in the bifurcated hydrogen bond on increasing the temperature. A slow motion has been observed in 55DMBP-H(2)ca by the (1)H and (14)N spin-lattice relaxation. An analysis of the spin-lattice relaxation data suggests a slow exchange between two non-planar conformations of the bipyridine molecule. PMID:21483963

Seliger, Janez; Žagar, Veselko; Asaji, Tetsuo; Gotoh, Kazuma; Ishida, Hiroyuki

2011-04-11

182

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

183

Classical toy models for the monopole shift and the quadrupole shift.  

PubMed

The penetration of s- and p(1/2)-electrons into the atomic nucleus leads to a variety of observable effects. The presence of s-electrons inside the nucleus gives rise to the isotope shift in atomic spectroscopy, and to the isomer shift in Mössbauer spectroscopy. Both well-known phenomena are manifestations of the more general monopole shift. In a recent paper (Koch et al., Phys. Rev. A, 2010, 81, 032507), we discussed the existence of the formally analogous quadrupole shift: a tensor correction to the electric quadrupole interaction due to the penetration of relativistic p(1/2)-electrons into the nucleus. The quadrupole shift is predicted to be observable by high-accuracy molecular spectroscopy on a set of 4 molecules (the quadrupole anomaly). The simple physics behind all these related phenomena is easily obscured by an elaborate mathematical formalism that is required for their derivation: a multipole expansion in combination with perturbation theory, invoking quantum physics and ideally relativity. In the present paper, we take a totally different approach. We consider three classical 'toy models' that can be solved by elementary calculus, and that nevertheless contain all essential physics of the monopole and quadrupole shifts. We hope that this intuitive (yet exact) analysis will increase the understanding about multipole shift phenomena in a broader community. PMID:22782015

Rose, Katrin; Cottenier, Stefaan

2012-07-11

184

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, S

2011-08-18

185

Skew quadrupole errors in the RHIC IR triplets  

SciTech Connect

From simulation studies of the RHIC lattice, we found that skew quadrupole errors and quadrupole roll misalignments in the IR triplets (where the {beta} function can be large) produce large vertical dispersions. A simple model, using only one triplet, is applied to obtain sensitivities of vertical dispersion to skew quadrupole errors. This study revealed that measuring the vertical dispersion in the triplets is a good tool for the diagnosis of local skew quadrupole correction.

Tepikian, S.; Peggs, S.

1993-12-31

186

Pioneer's Anomaly and the Solar Quadrupole Moment  

Microsoft Academic Search

The trajectories of test particles moving in the gravitational field of a non-spherically symmetric mass distribution become affected by the presence of multipole moments. In the case of hyperbolic trajectories, the quadrupole moment of an oblate mass induces a displacement of the trajectory towards the mass source, an effect that can be interpreted as an additional acceleration directed towards the

Hernando Quevedo

2005-01-01

187

A magnetic quadrupole from rectangular permanent magnets  

NASA Astrophysics Data System (ADS)

An analytical model of iron-free pure permanent magnet (PPM) quadrupole consisting of rectangular magnets is presented. Its strength is tunable via the retraction of four magnet arms so that it can be axially compact also. Its working principle is given by a theory of ideal rectangular PPM quadrupole developed from the theory of planar PPM undulators. It is simple to build and tune for minimization of the undesired higher harmonics arising in practice. It has demagnetizing fields limited to the linear region of the B-H curve. Its field quality is not degraded by anisotropic nonunit permeability of rare-earth alloys (like NdFeB, SmCo). Its parameters are suitable between ultra-compact high-gradient Halbach quadrupoles and low-gradient-medium-aperture iron pole current-fed quadrupoles. It can be suitable for applications like focussing inside a free electron laser cavity, horizontal focussing between contiguous undulators in XFELs or final focussing in scattering experiments.

Biswas, B.

2009-07-01

188

Hydrogen Isotope Analysis by Quadrupole Mass Spectrometry.  

National Technical Information Service (NTIS)

The analysis of isotopes of hydrogen (H, D, T) and helium ( exp 3 He, exp 4 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 Fusi...

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

1981-01-01

189

Closed orbit response to quadrupole strength variation  

SciTech Connect

We derive two formulae relating the variation in closed orbit in a storage ring to variations in quadrupole strength, neglecting nonlinear and dispersive effects. These formulae correct results previously reported [1,2,3]. We compare the results of the formulae applied to the ATF with simulations using MAD, and consider their application to beam-based alignment.

Wolski, Andrzej; Zimmermann, Frank

2004-01-20

190

Explosives detection with quadrupole resonance analysis  

Microsoft Academic Search

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

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

1997-01-01

191

Aberrations caused by mechanical misalignments in electrostatic quadrupole lens systems  

Microsoft Academic Search

Image aberrations resulting from small misalignments in quadrupole lenses multiplets have been analysed. Analytical formulas for the coefficients of the beam displacement, astigmatism and coma associated with misalignments in a general quadrupole lens system have been derived. Numerical computations of systems of three and four quadrupole lenses have also been carried out. The aberration figures obtained for systems with and

L. A. Baranova; F. H. Read

2001-01-01

192

Thermal analysis of SC quadrupoles in accelerator interaction regions  

SciTech Connect

This paper presents results of a thermal analysis and operation margin calculation performed for NbTi and Nb{sub 3}Sn low-beta quadrupoles in collider interaction regions. Results of the thermal analysis for NbTi quadrupoles are compared with the relevant experimental data. An approach to quench limit measurements for Nb{sub 3}Sn quadrupoles is discussed.

Novitski, Igor; Zlobin, Alexander V.; /Fermilab

2006-09-01

193

Quadrupole mode perturbation in storage rings  

NASA Astrophysics Data System (ADS)

Quadrupole mode oscillation (QMO) means the second moments of a system oscillating with time, or, the elliptical torus of the Hamiltonian rotating in phase space. We study the QMO in storage rings. In the transverse direction the QMO can be excited by an rf quadrupole. The strength of the rf quadrupole varies with time, and the oscillation frequency om must be close to two times the transverse betatron oscillation frequency o y. The perturbation equation is solved with the Hamiltonian method and we found the beam satisfies Boltzmann distribution. Mathieu instability occurs when 2(oy - C 1o0) < om < 2(oy + C1o 0), where C1 is the effective strength of the rf quadrupole and o0 is the revolution frequency. When a nonlinear detuning term is included, the multi-particle system will bifurcate after passing through the thresholds. The QMO can be detected by a Beam Position Monitor (BPM), and the emittance of the beam can be derived from the signal. The other applications of quadrupole mode perturbation include mismatch correction and spin resonance overcoming. In the longitudinal direction voltage modulation induces QMO. The Hamiltonian has the same form as the transverse nonlinear QMO Hamiltonian, therefore the beam dynamics and the properties are similar. QMO in the longitudinal direction can be used to compress the bunch in storage rings. Our research results show that the bunch can be compressed by a factor of 2˜3 in proton storage rings. This factor is smaller in electron storage rings due to radiation damping and quantum fluctuation. The more effective method, however, is using a harmonic cavity. Both methods are explored in the second part of this dissertation.

Guo, Weiming

194

Ground-state electric quadrupole moment of {sup 31}Al  

SciTech Connect

The ground-state electric quadrupole moment of {sup 31}Al(I{sup {pi}}=5/2{sup +},T{sub 1/2}=644(25) ms) has been measured by means of {beta}-ray-detected nuclear magnetic resonance spectroscopy using a spin-polarized {sup 31}Al beam produced in the projectile fragmentation reaction. The obtained Q moment, |Q{sub exp}({sup 31}Al)|=112(32) e mb, 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 {sup 31}Al is located outside of the island of inversion.

Nagae, D.; Takemura, M.; Asahi, K.; Takase, K.; Shimada, K.; Uchida, M.; Arai, T.; Inoue, T.; Kagami, S.; Hatakeyama, N. [Department of Physics, Tokyo Institute of Technology, 2-12-1 Oh-okayama, Meguro-ku, Tokyo 152-8551 (Japan); Ueno, H. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Department of Physics, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima-ku, Tokyo 171-8501 (Japan); Kameda, D.; Yoshimi, A.; Sugimoto, T.; Nagatomo, T. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Kawamura, H.; Narita, K.; Murata, J. [Department of Physics, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima-ku, Tokyo 171-8501 (Japan)

2009-02-15

195

Relativistic Effects in Many Electron Hyperfine Structure. III. Relativistic Dipole and Quadrupole Interaction in Europium and Remeasurement of the Nuclear Magnetic Dipole Moments of 151EU and ^ {153}Eu  

Microsoft Academic Search

The nuclear magnetic dipole moments of 151Eu and 153Eu have been re-measured. The revised values (corrected for diamagnetic shielding) are: mu(151Eu) = 3.4630 ± 0.0006 n.m., mu(153Eu) = 1.5292 ± 0.0008 n.m. The ratio of the moments is mu(151Eu)\\/mu(153Eu) = 2.26505 ± 0.00042. These results were obtained by the method of triple resonance in an atomic beam. The hyperfine structure

L. Evans; P. G. H. Sandars; G. K. Woodgate

1965-01-01

196

Observation of second-order quadrupole shift in Mössbauer spectrum of amorphous YIG (yttrium iron garnet)  

Microsoft Academic Search

A previously unsuspected quadrupole shift of the nuclear Zeeman lines in amorphous magnets has been observed by 57Fe Mössbauer spectroscopy in speromagnetic amorphous yttrium iron garnet at 4.2 K. The distinctive shift pattern is shown to arise theoretically as a second-order perturbation of the Zeeman levels by the distribution of electric field gradients in the amorphous state. It is observed

M. Eibschütz; M. E. Lines

1982-01-01

197

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

198

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

199

Permanent-magnet quadrupoles in RFQ Linacs  

SciTech Connect

We investigated the possibility of increasing the current-carrying capability of radio-frequency quadrupole (RFQ) linear accelerators by adding permanentmagnet quadrupole (PMQ) focusing to the existing transverse focusing provided by the rf electric field. Increased transverse focusing would also allow shortening RFQ linacs by permitting a larger accelerating gradient, which is normally accompanied by an undesirable increased transverse rf defocusing effect. We found that PMQs were not helpful in increasing the transverse focusing strength in an RFQ. This conclusion was reached after some particle tracing simulations and some analytical calculations. In our parameter regime, the addition of the magnets increases the betatron frequency but does not result in improved focusing because the increased flutter more than offsets the gain from the increased betatron frequency.

Lysenko, W.P.; Wang, T.F.

1985-10-01

200

Electric quadrupole moment of the proton halo nucleus {sup 8}B  

SciTech Connect

The {beta}-NQR (nuclear quadrupole resonance) signals of {sup 8}B (I{sup {pi}}=2{sup +},T{sub 1/2}=770 ms) implanted in TiO{sub 2} (rutile) have been detected to determine the electric quadrupole moment of {sup 8}B with high precision. The ratio of the quadrupole moments of {sup 8}B and {sup 12}B was determined as |Q({sup 8}B)/Q({sup 12}B)|=4.88{+-}0.04. Combined with the known sign, the quadrupole moment of {sup 8}B was obtained as Q({sup 8}B)=+(64.5{+-}1.4) mb, which is consistent with and more precise than the previously reported value. The experimental values of the Q moment, the proton and neutron radii and the density distribution of {sup 8}B were compared with several theoretical predictions and were found to be best reproduced by a microscopic cluster model, which suggests the existence of a proton halo.

Sumikama, T.; Nagatomo, T. [RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Ogura, M.; Iwakoshi, T.; Nakashima, Y.; Fujiwara, H.; Matsuta, K.; Fukuda, M.; Mihara, M. [Department of Physics, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043 (Japan); Minamisono, T. [Fukui University of Technology, 3-6-1 Gakuen, Fukui 910-8505 (Japan)

2006-08-15

201

Quadrupole Magnets for the SSC Collider  

SciTech Connect

A 40 mm bore 211 T/m quadrupole magnet has been designed and tested at LBL. There are 8 coils of 30 strand cable arranged in 2 layers in a cos 2{theta} distribution, supported by 18 mm thick collars, preassembled into 146 mm long packs, and rigidly aligned in a cold-iron yoke. The design, construction details, and test results are given for three 1 m models and the first 5 m model.

Taylor, C.E.; Barale, P.; Benjegerdes, R.; Caspi, S.; Dell'Orco, D.; Fritz, D.; Gilbert, W.; Lietzke, A.; Mirk, K.; Peters, C.; Scanlan, R.; Wandesforde, A.

1991-06-01

202

[23] Quadrupole ion trap mass spectrometry  

Microsoft Academic Search

A number of other features of ITMS systems that will enhance their ability to analyze biological macromolecules are worth mentioning. As has already been demonstrated for ESI\\/quadrupole, ESI\\/magnetic sector, and ESI\\/FTICR systems, the capability of inducing fragmentation of the ESI-generated multiply charged ions of biological macromolecules in the capillary\\/skimmer region of the ESI source and subsequently selectively analyzing fragments69 can

Jae C. Schwartz; Ian Jardine

1996-01-01

203

Electrostatic quadrupole DC accelerators for BNCT applications  

SciTech Connect

A dc electrostatic quadrupole (ESQ) accelerator is capable of producing a 2.5 MeV, 100 mA proton beam for the purpose of generating neutrons for Boron Neutron Capture Therapy. The ESQ accelerator is better than the conventional aperture column in high beam current application due to the presence of stronger transverse field for beam focusing and for suppressing secondary electrons. The major challenge in this type of accelerator is in developing the proper power supply system.

Kwan, J.W.; Anderson, O.A.; Reginato, L.L.; Vella, M.C.; Yu, S.S.

1994-04-01

204

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

205

NMR quadrupole interactions in vanadium phosphate glass  

Microsoft Academic Search

By means of absorption and dispersion mode spectra at frequencies of the 51V nucleus from 1.78 to 20 MHz, three unique vanadium sites in vanadium phosphate glass have been identified. The relative occupation of these sites is found to be compositionally dependent. Two of these sites have lower-bound quadrupole coupling constant values of 1.8 and 0.4 MHz which can be

M. Wadsworth; P. W. France

1986-01-01

206

LHC INTERACTION REGION QUADRUPOLE ERROR IMPACT STUDIES  

SciTech Connect

The performance of the Large Hadron Collider (LHC) at collision energy is limited by the field quality of the interaction region (IR) quadrupoles and dipoles. In this paper the authors study the impact of the expected field errors of these magnets on the dynamic aperture. The authors investigate different magnet arrangements and error strength. Based on the results they propose and evaluate a corrector layout to meet the required dynamic aperture performance in a companion paper.

FISCHER,W.; PTITSIN,V.; WEI,J.

1999-09-07

207

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

208

Far-field potential production by quadrupole generators in cylindrical volume conductors.  

PubMed

Far-field potentials have been observed clinically and recognized as such for approximately 30 years. Unfortunately a complete understanding of far-field potential generation is not yet at hand. An attractive model is the representation of an action potential by a quadrupole consisting of a leading and trailing dipole with respect to the direction of propagation. This investigation physically models an action potential by using a quadrupole constant current source and substantiates the concept that an action potential as modeled by two dipoles back-to-back is capable of producing far-field potentials in cylindrical volume conductors. The 4 postulated mechanisms of generating far-field potentials are validated, i.e., an action potential encountering (1) different size volume conductors, (2) the termination of excitable tissue, (3) a change in conducting medium conductivity, and (4) a bend in the nerve. A fifth postulated but previously not demonstrated method of far-field production, neural branching, is shown by the quadrupole model to also be capable of yielding far-field potentials. The termination of a volume conductor is also shown to be capable of generating a voltage difference across the quadrupole. Any of the above 6 conditions create an alteration in the symmetry of the leading and trailing dipole moments resulting in a transient potential difference across the quadrupole as recorded with a far-field recording montage. The potential difference produced by the asymmetric electric field between the leading and trailing dipoles recorded distantly in areas of low potential gradient is the so-called far-field potential. This investigation substantiates the utility of the leading/trailing dipole model of far-field production and offers a simple model of passive voltage distributions secondary to dipolar moment imbalances to better understand the generation of far-field potentials in cylindrical volume conductors. PMID:7691566

Dumitru, D; King, J C

209

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

210

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

211

Nuclear Schiff moment and soft vibrational modes  

SciTech Connect

The atomic electric dipole moment (EDM) currently searched by a number of experimental groups requires that both parity and time-reversal invariance be violated. According to current theoretical understanding, the EDM is induced by the nuclear Schiff moment. The enhancement of the Schiff moment by the combination of static quadrupole and octupole deformation was predicted earlier. Here we study a further idea of the possible enhancement in the absence of static deformation but in a nuclear system with soft collective vibrations of two types. Both analytical approximation and numerical solution of the simplified problem confirm the presence of the enhancement. We discuss related aspects of nuclear structure which should be studied beyond mean-field and random phase approximations.

Zelevinsky, Vladimir [Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824-1321 (United States); National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824-1321 (United States); Volya, Alexander [Department of Physics, Florida State University, Tallahassee, Florida 32306-4350 (United States); Auerbach, Naftali [Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824-1321 (United States); School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978 (Israel)

2008-07-15

212

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

2011-09-02

213

Impact of nuclear dipoles on polarization echoes in glasses  

Microsoft Academic Search

A few years ago surprising magnetic field effects were found in non- magnetic glasses at low temperatures (approx 10 mK). It has since been established that this effect can be attributed to the tunnelling motion of particles carrying nuclear quadrupole moments. The magnetic field effect saturates when the nuclear Zeeman energy becomes larger than the quadrupole splitting. For glycerol this

M. Bazrafshan; G. Fickenscher; M. v. Schickfus; A. Fleischmann; C. Enss

2007-01-01

214

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

215

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

216

Analytical Solutions of Singular Isothermal Quadrupole Lens  

NASA Astrophysics Data System (ADS)

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.; Yang, Xiaofeng

2013-06-01

217

Hybrid rare earth quadrupole drift tube magnets  

SciTech Connect

A prototype quadrupole permanent magnet with adjustable field strength has been constructed and tested. The magnet consists of iron pole pieces to provide the required field shape along with rare earth permanent magnet material (samarium cobalt) to energize the magnet. A unique feature of the configuration is the adjustability of the field by rotating the outer rings consisting of permanent magnets and iron. Magnetic tests show small field errors coming from well understood assembly details. Mechanical tests show the design needs further consideration to ensure reliability. It is planned to use this type of magnet in the SuperHILAC prestripper drift tubes.

Halbach, K.; Feinberg, B.; Green, M.I.; MacGill, R.; Milburn, J.; Tanabe, J.

1985-10-01

218

Hybrid rare earth quadrupole drift tube magnets  

SciTech Connect

A prototype quadrupole permanent magnet with adjustable field strength has been constructed and tested. The magnet consists of iron pole pieces to provide the required field shape along with rare earth permanent magnet material (samarium cobalt) to energize the magnet. A unique feature of the configuration is the adjustability of the field by rotating the outer rings consisting of permanent magnets and iron. Magnetic tests show small field errors coming from well understood assembly details. Mechanical tests show the design needs further consideration to ensure reliability. It is planned to use this type of magnet in the SuperHILAC prestripper drift tubes. 3 refs., 5 figs.

Halbach, K.; Feinberg, B.; Green, M.I.; MacGill, R.; Milburn, J.; Tanabe, J.

1985-05-01

219

The Quadrupole Response of Borromean Bosonic Trimers  

NASA Astrophysics Data System (ADS)

The inelastic response of a Borromean trimer composed of three identical bosons is explored. To this end we use the quadrupole approximation as the excitation mechanism of the bosonic system from its ground state. We utilize the hyperspherical-harmonics expansion to solve the Schroedinger equation and the Lorentz integral transform method to calculate the reaction. It is found that the magnitude of the response function and corresponding sum rules increase as a power law when approaching the three-body threshold. It is also found that this increase is governed by unnatural exponents.

Bazak, Betzalel; Liverts, Evgeny; Barnea, Nir

2013-05-01

220

Toroidal quadrupole form factor of the deuteron  

NASA Astrophysics Data System (ADS)

We calculate the toroidal quadrupole moment and form factor of the deuteron, which violate time-reversal symmetry but conserve parity, at leading order in two-flavor chiral effective field theory with perturbative pion exchange. We take into account time-reversal and parity violation owing to the QCD vacuum angle combined with parity violation resulting from the weak interaction in the Standard Model. We also consider time-reversal and parity violation that at the quark-gluon level results from effective dimension-six operators originating from physics beyond the Standard Model.

Mereghetti, E.; de Vries, J.; Timmermans, R. G. E.; van Kolck, U.

2013-09-01

221

The pipe-quadrupole, an alternative for high gradient interaction region quadrupole designs  

Microsoft Academic Search

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

J. M. Van Oort; R. M. Scanlan

1997-01-01

222

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

223

SSC Quadrupole Magnet Performance at LBL  

SciTech Connect

Lawrence Berkeley Laboratory (LBL) contracted to design, construct, and test four short (1m) models and six full-size (5m) models of the Superconducting Super Collider (SSC) main-ring 5 meter focusing quadrupole magnet (211 Tesla/meter). The training performance of these magnets is summarized. Magnets were tested in a horizontal boiling helium (1 Atm) cryostat. The magnetic, strain-gage and training responses to two thermal cycles were measured. The quadrupole gradient, and relative multipole purity were determined from Fourier analysis of the rotating coil signals. Magnetic and strain-gage measurements were taken on-the-fly. The voltage-tap data was analyzed to determine quench-origin and propagation characteristics. Quench-training proceeded at 4.3K until a plateau was achieved or sub-cooling (2.5K) was used to accelerate the training process. The early short (1m) magnets were also trained at 1.8K (10kA) to help identify potential weak areas. The MIITs were calculated to compare various magnet protection methods. Except for modest training above the anticipated SSC operating point, the magnets performed very well and proved to be self-protecting. Some design flaws were identified and corrected. The last two 1 m models and all the 5m models have been reinstalled in cryostats at the SSC Laboratory, retested and used to achieve various milestones in their program.

Lietzke, A.F.; Barale, P.; Benjegerdes, r.; Caspi, S.; Cortella, J.; Dell'Orco, D.; Gilbert, W.; Green, M.I.; Mirk, K.; Peters, C.; Scalan, R.; Taylor, C.E.; Wandesforde, A.

1992-10-01

224

The use of natural and archeological analogues for understanding the long-term behavior of nuclear glasses  

NASA Astrophysics Data System (ADS)

The knowledge of the long-term behavior of nuclear waste in anticipation of ultimate disposal in a deep geological formation is of prime importance in a waste management strategy. If phenomenological models have been developed to predict the long-term behavior of these materials, validating these models remains a challenge, when considering the time scale of radioactive decay of radionuclides of environmental concern, typically 10 4-10 5 yrs. Here we show how natural or archaeological analogues provide critical constraints not only on the phenomenology of glass alteration and the mechanisms involved, but also on the ability of experimental short-term data to predict long-term alteration in complex environments.

Libourel, Guy; Verney-Carron, Aurelie; Morlok, Andreas; Gin, Stéphane; Sterpenich, Jérôme; Michelin, Anne; Neff, Delphine; Dillmann, Philippe

2011-02-01

225

(Multi-)nucleon transfer and its role in understanding the transition from quasi-elastic scattering to deep inelastic collisions in nuclear reactions  

NASA Astrophysics Data System (ADS)

Measurements of (multi-)nucleon transfer excitation functions in backward-angle quasi-elastic scattering at near- barrier energies have been carried out, using beams of ^16O and ^32S [1]. A detailed comparison of the measured transfer probabilities within the coupled-channels framework indicates a major problem with the standard coupled-channels approach. The experimental results show events with large kinetic energy losses, which are not treated in the coherent coupled channels model. The presence of these deep inelastic collision processes already seen at sub-barrier energies, leads to questions of what the physical processes are behind the transition from quasi- elastic scattering to deep inelastic collisions, and how processes leading to large total kinetic energy losses may be included in nuclear reaction models. Our observations point to the need to include effects of quantum decoherence in a new nuclear reaction model [2], and promises a new understanding of nucleus-nucleus collisions, with implications for areas such as nuclear astrophysics and nucleosynthesis.References[1] M. Evers et al., Phys. Rev. C78, 034618 (2007)[2] D. Hinde et al., Nuc. Phys. A834, 117c-122c (2010)

Evers, Maurits; Hinde, David; Dasgupta, Mahananda

2010-11-01

226

Electric Quadrupole Moments of Neutron Rich Al Isotope  

SciTech Connect

The electric quadrupole moment Q for the ground state of neutron-rich 31,32Al has been measured using {beta}-NMR method applied to spin-polarized projectile fragments. The obtained quadrupole moments are smaller than those of 27,28Al, which suggests spherical shapes of 31,32Al.

Yoshimi, A.; Ueno, H.; Kameda, D.; Sugimoto, T. [Nishina Center for Accelerator-based Science, RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan); Asahi, K.; Nagae, D.; Takemura, M.; Shimada, K.; Takase, K.; Uchida, M.; Arai, T.; Inoue, T. [Department of Physics, Tokyo Institute of Technology, Oh-okayama 2-12-1, Meguro, Tokyo 152-8551 (Japan); Murata, J.; Kawamura, H. [Department of Physics, Rikkyo University, 3-34-1, Nishi-Ikebukuro, Toshima, Tokyo 171-8501 (Japan)

2007-05-22

227

Fifth-order aperture aberration of electrostatic quadrupole lens systems  

Microsoft Academic Search

The fifth order aperture aberration is investigated in three types of quadrupole lens systems: the conventional regular antisymmetric quadruplet, the quadruplet made of combined quadrupole-octupole systems in which the third order aperture aberration is eliminated, and the mid- acceleration quadruplet produced by applying an accelerating voltage to the two middle lenses that results in the essential reduction of the aperture

Lubov A. Baranova

2000-01-01

228

Anamorphotic quadrupole lens system for highly demagnified round spot  

Microsoft Academic Search

Paraxial and aberration properties have been studied theoretically for an electrostatic quadrupole lens system that demagnifies the line shaped emission area with a high aspect ratio of a LaB6 source to a sub-micron round spot. For a quadrupole lens doublet, it was indicated that the target paraxial performances, Mx = 1100 and My = 11000, can be achieved with a

Yuichiro Yamazaki; Motosuke Miyoshi

1995-01-01

229

Energy contribution of the quadrupole perturbation of central gravitational field.  

National Technical Information Service (NTIS)

The solution of Einstein equations with the Minkowski space condition for the central field with a quadrupole perturbation is calculated as an 1/r-expansion up to terms quadratic in the first quadrupole constant. It is shown that the perturbation is shown...

S. N. Sokolov

1990-01-01

230

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

231

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

232

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 throughout the assembly.

Maschke, Alfred W. (East Moriches, NY)

1985-01-01

233

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

234

Zoom quadrupole focusing systems producing an image of an object  

Microsoft Academic Search

The main difference between quadrupole and axisymmetric charge particle beam focusing systems is that quadrupole systems do not produce a regular image of an object like axisymmetric systems. Because of the special symmetry in geometry and electric or magnetic fields along the axis, only the Russian quadruplet (RQ) can produce an image, however, for each geometry and given maximum field

Alexander D. Dymnikov; Gary A. Glass; Bibhudutta Rout

2005-01-01

235

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

236

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

237

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.; /Fermilab

2006-09-01

238

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, A. G.

1994-10-01

239

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

240

Systematics of isovector and isoscalar giant quadrupole resonances in normal and superfluid spherical nuclei  

NASA Astrophysics Data System (ADS)

The isoscalar (IS) and isovector (IV) quadrupole responses of nuclei are systematically investigated using the time-dependent Skyrme energy density functional including pairing in the BCS approximation. Using two different Skyrme functionals, Sly4 and SkM*, respectively 263 and 324 nuclei have been found to be spherical along the nuclear charts. The time-dependent evolution of these nuclei has been systematically investigated, giving access to their quadrupole responses. It is shown that the mean energy of the collective high-energy state globally reproduces the experimental IS and IV collective energy but fails to reproduce their lifetimes. It is found that the mean collective energy depends rather significantly on the functional used in the mean-field channel. Pairing by competing with parity effects can slightly affect the collective response around magic numbers and induces a reduction of the collective energy compared to the average trend. Low-lying states, that can only be considered if pairing is included, are investigated. While the approach provides a fair estimate of the low-lying state energy, it strongly underestimates the transition rate B(E2). Finally, the possibility to access the density dependence of the symmetry energy through parallel measurements of both the IS and IV giant quadrupole resonances is discussed.

Scamps, Guillaume; Lacroix, Denis

2013-10-01

241

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

Project, Iowa P.

2004-01-01

242

Measurement of the electric quadrupole moment of N2O  

NASA Astrophysics Data System (ADS)

Measurements of the temperature dependence of the Buckingham effect (electric-field-gradient-induced birefringence, EFGIB) for gaseous nitrous oxide are presented. Measurements span the temperature range 298.5-473.9 K, which allows for separation of the temperature-independent hyperpolarizability term from the temperature-dependent quadrupole term, yielding a quadrupole moment of ? = (-11.03 +/- 0.41) × 10-40 C m2, and a hyperpolarizability term of b = (-0.638 +/- 0.063) × 10-60 C3 m4 J-2. For dipolar molecules, the quadrupole moment is origin dependent, and the value reported here is referred to an origin called the effective quadrupole center (EQC). Comparison of this value with the center of mass (CM) quadrupole moment obtained from MBER experiments yields information about the dynamic dipole-quadrupole and dipole-magnetic dipole polarizabilities. The temperature-independent term, previously assumed to contribute negligibly to the EFGIB, is found to contribute some (5.2 +/- 0.6)% to the effect at room temperature and clearly needs to be accounted for if the quadrupole moment is to be definitively established.

Chetty, Naven; Couling, Vincent W.

2011-04-01

243

Measurement of the electric quadrupole moment of CO  

NASA Astrophysics Data System (ADS)

Measurements of the temperature dependence of the Buckingham effect (electric-field-gradient-induced birefringence, EFGIB) for gaseous carbon monoxide are presented. The measurements span the temperature range 301.2-473.9 K, which allows for separation of the temperature-independent hyperpolarizability contribution from the temperature-dependent quadrupole contribution. It is demonstrated that in the case of carbon monoxide, quantization of the rotational motion of the molecules needs to be considered, the analysis yielding a quadrupole moment of ? = (-8.77 +/- 0.31) × 10-40 C m2 and a hyperpolarizability term of b' = (-0.1243 +/- 0.0078) × 10-60 C3 m4 J-2. For dipolar molecules, the quadrupole moment is origin dependent, and the value reported here is referred to an origin called the effective quadrupole center. Comparison of this value with the center-of-mass quadrupole moment obtained from other experiments yields information about the dynamic dipole-quadrupole and dipole-magnetic dipole polarizabilities. The temperature-independent term, which contributes (7.0 +/- 0.6)% to the EFGIB at room temperature, is by no means insignificant, and must necessarily be accounted for if the quadrupole moment is to be definitively established. The measured ? and b' are compared with the best available ab initio calculated values.

Chetty, Naven; Couling, Vincent W.

2011-04-01

244

Quadrupole Coupling Parameters and Structural Aspects of Crystalline and Amorphous Solids by NMR and Nqr.  

NASA Astrophysics Data System (ADS)

Nuclear quadrupole interaction is very sensitive to the local electron distribution and chemical bondings. NMR and NQR techniques have been combined to obtain the quadrupole coupling constant ({Qcc}) and asymmetry parameter (eta) and extract structural information for several borate, gallate, and metavanadate compounds and glasses. ^{71}Ga and ^{69}Ga NMR has been used to study crystalline beta-Ga _2O_3 and several gallate glasses. Quadrupole parameters were acquired for GaO_6 and GaO_4 units in beta-Ga_2 O_3 by the computer simulation of the NMR powder patterns. A sensitive CW NQR spectrometer was built to detect NQR resonances below 2 MHz. The spectrometer includes a modified Robinson oscillator-detector, a new bi-symmetric square wave Zeeman modulator and a computerized data acquisition system. ^{51}V (I = 7/2) NQR resonances below 850 kHz have been detected for several metavanadates at both room temperature and liquid nitrogen temperature. Quadrupole parameters thus obtained are an order of magnitude more accurate than values obtained by previous NMR studies. For a spin 3/2 nucleus, the pure NQR frequency {Q_{cc}over 2}sqrt{1+{eta^2over 3}}is insufficient to determine either Q_{cc} or eta. However, two methods, Zeeman perturbed NQR powder pattern and ^{10}B NQR, can be employed to obtain both Q_{cc } and eta. An example is given for ^{11}B in CaO-B_2O_3. With a double coil tank circuit design, pure ^ {11}B NQR was used to determine the fraction of borons in BO_3 and BO _4 configurations in hydrated zinc borates. ^{11}B NMR and NQR were also used to study lead borate glasses. Small changes in Q_{cc} (less than 2%) and eta (less than 0.1) suggest that BO_3 units with non-bridging oxygens are not present in the lead borate glasses.

Mao, Degen

245

Measurement of the local-moment-induced electric-quadrupole splitting of dilute 198Au in iron by NMR on oriented nuclei  

NASA Astrophysics Data System (ADS)

The magnetic-dipole and electric-quadrupole hyperfine splitting frequencies ?M=|g?NBhfh| and ?Q=e2qQh of dilute 198Au (j?=2- T12=2.7 d) in iron were measured with nuclear magnetic resonance on oriented nuclei as 259.48(3) MHz and -2.08(4) MHz, respectively. The quadrupole splitting disagrees in magnitude and sign with the published value measured with single-passage NMR on oriented nuclei. Taking into account the known magnetic and electric hyperfine splittings for 199Au in Fe, the ratio of nuclear quadrupole moments is deduced to be Q(198Au)Q(199Au)=1.37(3). The experimental hyperfine anomalies between 197Au, 198Au, and 199Au in Fe are discussed in the context of noncontact hyperfine fields.

Hagn, E.; Zech, E.

1984-02-01

246

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

247

High-Efficiency Resonant Cavity Quadrupole Moment Monitor  

SciTech Connect

Measurement of the beam quadrupole moment at several locations can be used to reconstruct the beam envelope and emittance parameters. The measurements can be performed in a non-intercepting way using a set of quadrupole-mode cavities. We present a cavity design with an optimized quadrupole moment shunt impedance. The cavity properties can be characterized using a wire test method to insure symmetry about the central axis, and alignment to nearby position sensing cavities. The design and characterization of the prototype structure is discussed.

Barov, N.; Nantista, C.D.; Miller, R.H.; Kim, J.S.; /FARTECH, San Diego /SLAC

2007-04-13

248

Magnetic-field-controlled tuning of the effective quadrupole interaction of Au in hcp Co  

NASA Astrophysics Data System (ADS)

We report nuclear magnetic resonance on oriented nuclei (NMR-ON) measurements on 198Au in a hcp Co single crystal which was magnetized with an external magnetic field Bext = 0-2 T applied at different angles with respect to the crystal c-axis. These experiments showed that the effective electric field gradient can be ``tuned'' continuously with the magnetic field, which opens new possibilities for the determination of small electric field gradients originating from an unquenched orbital momentum, and for the measurement of electric quadrupole moments of radioactive nuclei.

Schmid, R.; Hinfurtner, B.; Hagn, E.; Zech, E.; Deicher, M.

1993-03-01

249

Minimisation of the aberrations of electrostatic lens systems composed of quadrupole and octupole lenses  

Microsoft Academic Search

Aberrations are investigated and compared for two types of multiplets based on electrostatic quadrupole and octupole lenses: “mid-acceleration” systems where an accelerating potential is applied to the middle lenses of a set of quadrupole lenses and systems where some of the quadrupole lenses are replaced by combined quadrupole–octupole lenses. It is shown that for systems consisting of three lenses the

L. A. Baranova; F. H. Read

1999-01-01

250

Synchrotron tune adjustment by longitudinal motion of quadrupoles  

SciTech Connect

Adjustment of the tune of a synchrotron is generally accomplished by globally varying the strength of the quadrupoles, either in the main quadrupole bus or in a set of dedicated trim quadrupoles distributed around the ring. An alternate scheme for tune control involves varying the strengths of quadrupoles only within a local insert, thereby adjusting the phase advance across the insert to create a ``phase trombone``. In a synchrotron built of permanent magnets, such as the proposed Fermilab Recycler Ring, tune adjustment may also be accomplished by constructing a phase trombone in which the longitudinal position rather than the strength of a number of quadruples is adjusted. Design philosophies and performance for such phase trombones are presented.

Bertche, K.J.

1996-07-01

251

Vector Potential and Stored Energy of a Quadrupole Magnet Array  

SciTech Connect

The vector potential, magnetic field and stored energy of a quadrupole magnet array are derived. Each magnet within the array is a current sheet with a current density proportional to the azimuthal angle 2{theta} and the longitudinal periodicity (2m-1){pi}/L. Individual quadrupoles within the array are oriented in a way that maximizes the field gradient The array does not have to be of equal spacing and can be of a finite size, however when the array is equally spaced and is of infinite size the solution can be simplified. We note that whereas, in a single quadrupole magnet with a current density proportional to cos2{theta} the gradient is pure, such purity is not preserved in a quadrupole array.

Caspi, S.

1999-03-15

252

Investigation of two extremal problems of quadrupole wing theory  

NASA Astrophysics Data System (ADS)

Two extremum problems concerning wings are analyzed on the basis of Panchenkov's quadrupole theory. Particular emphasis is placed on the problem of optimizing the geometry of a low-aspect-ratio wing near a screen.

Sidunova, L. E.

253

Beam based alignment of C-shaped quadrupole magnets  

SciTech Connect

Many storage rings have implemented a method of finding the positional offset between the electrical center of the beam position monitors (BPM) and the magnetic center of the adjacent quadrupole magnets. The algorithm for accomplishing this is usually based on modulating the current in the quadrupole magnet and finding the beam position that minimizes the orbit perturbation. When the quadrupole magnet is C-shaped, as it is for many light sources, the modulation method can produce an erroneous measurement of the magnetic center in the horizontal plane. When the current in a C-shaped quadrupole is changed, there is an additional dipole component in the vertical field. Due to nonlinearities in the hysteresis cycle of the C-magnet geometry, the beam-based alignment technique at the Advanced Light Source (ALS) deviated horizontally by .5 mm from the actual magnetic center. By modifying the technique, the offsets were measured to an accuracy of better than 50 {micro}m.

Portmann, G.; Robin, D.

1998-06-01

254

A small-bore high-field superconducting quadrupole magnet  

SciTech Connect

A prototype superconducting quadrupole magnet was designed and built for use in superconducting coupled-cavity linacs where the use of permanent magnets is ruled out by consideration of trapped flux losses. The magnet has a clear bore diameter of 1.8 cm and outside diameter of 11 cm and length of 11 cm. The magnet was operated at a temperature of 4.2 K and obtained a peak quadrupole field gradient of 320 T/m.

Barlow, D.B.; Kraus, R.H.; Lobb, C.T.; Menzel, M.T. (Los Alamos National Lab., NM (USA)); Walstrom, P.L. (Grumman Space Systems, Los Alamos, NM (USA))

1990-01-01

255

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

256

Chip-Scale Quadrupole Mass Filters for Portable Mass Spectrometry  

Microsoft Academic Search

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 electrodes, ion optics, and housing into a single monolithic block. This process eliminates the electrode-to-housing misalignments inherent in other QMFs and enables the implementation of complex device architectures. To

Kerry Cheung; Luis Fernando Velasquez-Garcia; Akintunde Ibitayo Akinwande

2010-01-01

257

Application of the Thermal Quadrupoles Method to Semitransparent Solids  

NASA Astrophysics Data System (ADS)

In this study, the thermal quadrupoles method is extended to semitransparent layered solids. Using this method, the surface temperature of semitransparent multilayered materials is calculated as a function of the optical and thermal properties of each layer. This result eventually leads to determination of the thermal diffusivity, thermal resistance, and/or optical absorption coefficient of layered materials using photothermal techniques. The thermal quadrupoles method is applied to determine the thermal contact resistance in glass stacks.

Salazar, A.; Fuente, R.; Mendioroz, A.; Apiñaniz, E.; Celorrio, R.

2012-11-01

258

Errors in radio-frequency quadrupole structures  

SciTech Connect

Performance degradation caused by certain radio-frequency quadrupole (RFQ) machine errors was studied using an efficient 3-D particle-tracing simulation code for a high-brightness example. Matched beams, for which no emittance growth occurs, exist for periodic structures and were used as input beams for particle tracing in the presence of errors. We considered both slowly varying and fast (random) errors that destroy periodicity. Random dipole errors cause emittance growth because of the mismatches they introduce and also result in a motion of the beam centroid that causes a reduction in acceptance. Because of the way RFQs are manufactured, the random error amplitudes can be kept below harmful levels. More important are the slow errors, which are harmful because they reduce acceptance even though they maintain a match (up to the point of particle loss). Slow dipole errors steer the beam toward the wall, and voltage deficiencies cause instabilities in the longitudinal direction resulting in particles not being accelerated to full energy.

Lysenko, W.P.

1983-01-01

259

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

260

Adjustable rare earth quadrupole drift tube magnets  

SciTech Connect

A prototype permanent-magnet drift tube quadrupole with adjustable field strength has been constructed and tested. The magnet uses iron pole pieces to provide the required field shape along with rare earth permanent-magnet material (samarium cobalt) to energize the magnet. A unique feature of the configuration is the adjustability of the field, accomplished by rotating the outer rings consisting of permanent magnets and iron. In contrast with a previous prototype magnet, this new design uses ball bearings in place of slide bearings to eliminate potential failures. The rotation is now achieved with a bevel gear mechanism. The prototype design also incorporates a new drift tube shell vacuum seal to allow easy disassembly. Tests were made of the magnetic properties and the mechanical performance of this magnet. Field errors are extremely small, and the magnet passed an accelerated ten year lifetime test. It is planned to use this type of magnet to replace 24 of the SuperHILAC prestripper drift tubes.

Feinberg, B.; Tanabe, J.; Halbach, K.; Koehler, G.; Green, M.I.

1987-03-01

261

The Sandia nuclear microprobe  

Microsoft Academic Search

A nuclear microprobe analysis system attached to Sandia's EN tandem Van de Graaff accelerator is described. A magnetic quadrupole doublet lens is used for the final focus and 2-(SIGMA)m beam diameters have been obtained. Several illustrative applications of the microprobe, including the first three dimensional concentration profiles using Rutherford backscattering and elastic recoil detection ever measured, are given.

B. L. Doyle; N. D. Wing

1982-01-01

262

Sandia nuclear microprobe  

SciTech Connect

A nuclear microprobe analysis system attached to Sandia's EN tandem Van de Graaff accelerator is described. A magnetic quadrupole doublet lens is used for the final focus and 2-..mu..m beam diameters have been obtained. Several illustrative applications of the microprobe, including the first three-dimensional concentration profiles using Rutherford backscattering and elastic recoil detection ever measured, are given.

Doyle, B.L.; Wing, N.D.

1982-11-01

263

Quadrupole collective dynamics from energy density functionals: Collective Hamiltonian and the interacting boson model  

SciTech Connect

Microscopic energy density functionals have become a standard tool for nuclear structure calculations, providing an accurate global description of nuclear ground states and collective excitations. For spectroscopic applications, this framework has to be extended to account for collective correlations related to restoration of symmetries broken by the static mean field, and for fluctuations of collective variables. In this paper, we compare two approaches to five-dimensional quadrupole dynamics: the collective Hamiltonian for quadrupole vibrations and rotations and the interacting boson model (IBM). The two models are compared in a study of the evolution of nonaxial shapes in Pt isotopes. Starting from the binding energy surfaces of {sup 192,194,196}Pt, calculated with a microscopic energy density functional, we analyze the resulting low-energy collective spectra obtained from the collective Hamiltonian, and the corresponding IBM Hamiltonian. The calculated excitation spectra and transition probabilities for the ground-state bands and the {gamma}-vibration bands are compared to the corresponding sequences of experimental states.

Nomura, K.; Vretenar, D. [Department of Physics, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Physics Department, Faculty of Science, University of Zagreb, 10000 Zagreb (Croatia); Niksic, T. [Physics Department, Faculty of Science, University of Zagreb, 10000 Zagreb (Croatia); Otsuka, T. [Department of Physics, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Center for Nuclear Study, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824-1321 (United States); Shimizu, N. [Department of Physics, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Center for Nuclear Study, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

2011-07-15

264

First-post-Newtonian quadrupole tidal interactions in binary systems  

NASA Astrophysics Data System (ADS)

We consider orbital-tidal coupling in a binary stellar system to first-post-Newtonian (1PN) order. We derive the orbital equations of motion for bodies with spins and mass quadrupole moments and show that they conserve the total linear momentum of the binary. We note that spin-orbit coupling must be included in a 1PN treatment of tidal interactions in order to maintain consistency (except in the special case of adiabatically induced quadrupoles): the inclusion of 1PN quadrupolar tidal effects while omitting spin effects would lead to a failure of momentum conservation for generic evolution of the quadrupoles. We use momentum conservation to specialize our analysis to the system’s center-of-mass-energy frame; we find the binary’s relative equation of motion in this frame and also present a generalized Lagrangian from which it can be derived. We then specialize to the case in which the quadrupole moment is adiabatically induced by the tidal field (in which case it is consistent to ignore spin effects). We show how the adiabatic dynamics for the quadrupole can be incorporated into our action principle and present the simplified orbital equations of motion and conserved energy for the adiabatic case. These results are relevant to the gravitational-wave signal of inspiralling binary neutron stars.

Vines, Justin E.; Flanagan, Éanna É.

2013-07-01

265

Higher order parametric excitation modes for spaceborne quadrupole mass spectrometers  

NASA Astrophysics Data System (ADS)

This paper describes a technique to significantly improve upon the mass peak shape and mass resolution of spaceborne quadrupole mass spectrometers (QMSs) through higher order auxiliary excitation of the quadrupole field. Using a novel multiresonant tank circuit, additional frequency components can be used to drive modulating voltages on the quadrupole rods in a practical manner, suitable for both improved commercial applications and spaceflight instruments. Auxiliary excitation at frequencies near twice that of the fundamental quadrupole RF frequency provides the advantages of previously studied parametric excitation techniques, but with the added benefit of increased sensed excitation amplitude dynamic range and the ability to operate voltage scan lines through the center of upper stability islands. Using a field programmable gate array, the amplitudes and frequencies of all QMS signals are digitally generated and managed, providing a robust and stable voltage control system. These techniques are experimentally verified through an interface with a commercial Pfeiffer QMG422 quadrupole rod system. When operating through the center of a stability island formed from higher order auxiliary excitation, approximately 50% and 400% improvements in 1% mass resolution and peak stability were measured, respectively, when compared with traditional QMS operation. Although tested with a circular rod system, the presented techniques have the potential to improve the performance of both circular and hyperbolic rod geometry QMS sensors.

Gershman, D. J.; Block, B. P.; Rubin, M.; Benna, M.; Mahaffy, P. R.; Zurbuchen, T. H.

2011-12-01

266

Higher order parametric excitation modes for spaceborne quadrupole mass spectrometers  

SciTech Connect

This paper describes a technique to significantly improve upon the mass peak shape and mass resolution of spaceborne quadrupole mass spectrometers (QMSs) through higher order auxiliary excitation of the quadrupole field. Using a novel multiresonant tank circuit, additional frequency components can be used to drive modulating voltages on the quadrupole rods in a practical manner, suitable for both improved commercial applications and spaceflight instruments. Auxiliary excitation at frequencies near twice that of the fundamental quadrupole RF frequency provides the advantages of previously studied parametric excitation techniques, but with the added benefit of increased sensed excitation amplitude dynamic range and the ability to operate voltage scan lines through the center of upper stability islands. Using a field programmable gate array, the amplitudes and frequencies of all QMS signals are digitally generated and managed, providing a robust and stable voltage control system. These techniques are experimentally verified through an interface with a commercial Pfeiffer QMG422 quadrupole rod system. When operating through the center of a stability island formed from higher order auxiliary excitation, approximately 50% and 400% improvements in 1% mass resolution and peak stability were measured, respectively, when compared with traditional QMS operation. Although tested with a circular rod system, the presented techniques have the potential to improve the performance of both circular and hyperbolic rod geometry QMS sensors.

Gershman, D. J.; Block, B. P.; Rubin, M.; Zurbuchen, T. H. [Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor, Michigan 48109 (United States); Benna, M.; Mahaffy, P. R. [Solar Systems Exploration Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771 (United States)

2011-12-15

267

Accumulation of nuclear DNA damage or neuron loss: Molecular basis for a new approach to understanding selective neuronal vulnerability in neurodegenerative diseases  

PubMed Central

According to a long-standing hypothesis, aging is mainly caused by accumulation of nuclear (n) DNA damage in differentiated cells such as neurons due to insufficient nDNA repair during lifetime. In line with this hypothesis it was until recently widely accepted that neuron loss is a general consequence of normal aging, explaining some degree of decline in brain function during aging. However, with the advent of more accurate procedures for counting neurons, it is currently widely accepted that there is widespread preservation of neuron numbers in the aging brain, and the changes that do occur are relatively specific to certain brain regions and types of neurons. Whether accumulation of nDNA damage and decline in nDNA repair is a general phenomenon in the aging brain or also shows cell-type specificity is, however, not known. It has not been possible to address this issue with the biochemical and molecular-biological methods available to study nDNA damage and nDNA repair. Rather, it was the introduction of autoradiographic methods to study quantitatively the relative amounts of nDNA damage (measured as nDNA single-strand breaks) and nDNA repair (measured as unscheduled DNA synthesis) on tissue sections that made it possible to address this question in a cell-type-specific manner under physiological conditions. The results of these studies revealed a formerly unknown inverse relationship between age-related accumulation of nDNA damage and age-related impairment in nDNA repair on the one hand, and the age-related, selective, loss of neurons on the other hand. This inverse relation may not only reflect a fundamental process of aging in the central nervous system but also provide the molecular basis for a new approach to understand the selective neuronal vulnerability in neurodegenerative diseases, particularly Alzheimer’s disease.

Brasnjevic, Ivona; Hof, Patrick R.; Steinbusch, Harry W.M.; Schmitz, Christoph

2010-01-01

268

New Operational Mode of Space-borne Quadrupole Mass Spectrometers  

NASA Astrophysics Data System (ADS)

Quadrupole mass spectrometers are the most widely used type of mass spectrometer for the analysis of neutrals from planetary sources. We provide a new implementation of a novel operating mode such quadrupole mass spectrometers (QMS) which substantially increases the mass resolution of these high-heritage sensors. This mode has direct applications for future planetary science and cometary missions. This new operational mode is achieved through amplitude modulation of the QMS RF waveform. This modulation leads to improved performance of existing sensors, enabling measurements over a significantly larger mass range. We implement this modulation mode as single sideband (SSB) modulation of the fundamental RF waveform, driving a multiple resonant tank circuit. An FPGA based power control system has been developed which provides flexibility in the selection of an operating point. This control system is interfaced with an existing quadrupole mass spectrometer with circular rod cross section to experimentally demonstrate the advantages of implementing a SSB modulation based solution.

Gershman, D. J.; Block, B.; Rubin, M.; Mahaffy, P. R.; Zurbuchen, T.

2010-12-01

269

Quadrupole moments of odd-odd near-magic nuclei  

NASA Astrophysics Data System (ADS)

Ground state quadrupole moments of odd-odd near-double-magic nuclei are calculated in the approximation of non-interacting odd neutron and odd proton. Under such a simple approximation the problem is reduced to the calculations of quadrupole moments of corresponding odd-even nuclei. These calculations are performed within the self-consistent Theory of Finite Fermi Systems based on the Energy Density Functional by Fayans et al. with the known DF3-a parameters. A reasonable agreement with the available experimental data is obtained for odd-odd nuclei and odd near-magic nuclei investigated. The self-consistent approach under consideration allowed us to predict the unknown quadrupole moments of odd-even and odd-odd nuclei near the double-magic 56,78Ni, 100,132Sn nuclides.

Voitenkov, D.; Achakovskiy, O.; Kamerdzhiev, S.; Tolokonnikov, S.

2012-12-01

270

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

271

Statistical thermodynamics of fluids with both dipole and quadrupole moments.  

PubMed

New Gibbs ensemble simulation data for a polar fluid modeled by a square-well potential plus dipole-dipole, dipole-quadrupole, and quadrupole-quadrupole interactions are presented. This simulation data is used in order to assess the applicability of the multipolar square-well perturbation theory [A. L. Benavides, Y. Guevara, and F. del Ri?o, Physica A 202, 420 (1994)] to systems where more than one term in the multipole expansion is relevant. It is found that this theory is able to reproduce qualitatively well the vapor-liquid phase diagram for different multipolar moment strengths, corresponding to typical values of real molecules, except in the critical region. Hence, this theory is used to model the behavior of substances with multiple chemical bonds such as carbon monoxide and nitrous oxide and we found that with a suitable choice of the values of the intermolecular parameters, the vapor-liquid equilibrium of these species is adequately estimated. PMID:21702567

Benavides, Ana L; Delgado, Francisco J García; Gámez, Francisco; Lago, Santiago; Garzón, Benito

2011-06-21

272

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{degree} rotation of the outer ring of iron and magnet material.

Barlow, D.B.; Kraus, R.H. Jr.; Martinez, R.P.; Meyer, R.E. [Los Alamos National Lab., NM (United States)

1994-07-01

273

OPERATIONAL MEASUREMENT OF COUPLING BY SKEW QUADRUPOLE MODULATION.  

SciTech Connect

The measurement and correction of the residual betatron coupling via skew quadrupole modulation is a new diagnostics technique that has been developed and tested at the Relativistic Heavy Ion Collider (RHIC) as a very promising method for the linear decoupling on the ramp. By modulating the strengths of the skew quadrupole families the two eigentune modulations are precisely measured with a high resolution phase lock loop system. The projections of the residual coupling coefficient onto the skew quadrupole coupling modulation direction are determined. The residual linear coupling could be corrected according the measurement. We report the results from the dedicated beam studies carried on at RHIC injection, store and on the ramp. A capability of measuring coupling on the ramp opens possibility of continuous coupling corrections during acceleration.

LUO.Y.CAMERON,P.LEE,R.ET AL.

2004-07-05

274

Study of a micro chamber quadrupole mass spectrometer  

SciTech Connect

The design of a micro chamber quadrupole mass spectrometer (MCQMS) having a small total volume of only 20 cm{sup 3}, including Faraday cup ion detector and ion source, is described. This MCQMS can resist a vacuum baking temperature of 400-500 deg. C. The quadrupole elements with a hyperbolic surface are made of a ceramic material and coated with a thin metal layer. The quadrupole mass filter has a field radius of 3 mm and a length of 100 mm. Prototypes of this new MCQMS can detect a minimum partial pressure of 10{sup -8} Pa, have a peak width of {delta}M=1 at 10% peak height from mass number 1 to 60, and show an excellent long-term stability. The new MCQMS is intended to be used in residual gas analyses of electron devices during a mutual pumping and baking process.

Wang Jinchan; Zhang Xiaobing; Mao Fuming; Xiao Mei; Cui Yunkang; Engelsen, Daniel den; Lei Wei [Jiangsu Information Display Engineering Research Center, School of Electronic Science and Engineering, Southeast University, Nanjing 210096 (China)

2008-03-15

275

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

276

Design and performance of the SRRC quadrupole magnets  

NASA Astrophysics Data System (ADS)

Forty-eight quadrupole magnets have been manufactured in this present work for the SRRC storage ring. Four families of quadrupole magnets with various magnetic lengths are used in the storage ring. The same pole contour with a bore diameter of 76 mm is computed via the 'MAGNET' program. The magnet design and procedure of mechanical fabrication and assembly are also described. The auxiliary coils are incorporated in the main coils for trimming the field strength of each individual magnet. Pole tip ends have a 6 mm x 6 mm chamfer so as to reduce the dodecapole in the end of magnet. Field mapping results having achieved the deviation of integral quadrupole field within +/-1 x 10(exp - 3) in a 30 mm bore radius region is also confirmed.

Chang, C. H.; Chen, H. H.; Hwang, C. S.; Hwang, G. J.; Tseng, P. K.

1994-07-01

277

Extension of the measurement capabilities of the quadrupole resonator  

NASA Astrophysics Data System (ADS)

The quadrupole resonator, designed to measure the surface resistance of superconducting samples at 400 MHz has been refurbished. The accuracy of its RF-dc compensation measurement technique is tested by an independent method. It is shown that the device enables also measurements at 800 and 1200 MHz and is capable to probe the critical RF magnetic field. The electric and magnetic field configuration of the quadrupole resonator are dependent on the excited mode. It is shown how this can be used to distinguish between electric and magnetic losses.

Junginger, T.; Weingarten, W.; Welsch, C.

2012-06-01

278

Extension of the measurement capabilities of the quadrupole resonator.  

PubMed

The quadrupole resonator, designed to measure the surface resistance of superconducting samples at 400 MHz has been refurbished. The accuracy of its RF-dc compensation measurement technique is tested by an independent method. It is shown that the device enables also measurements at 800 and 1200 MHz and is capable to probe the critical RF magnetic field. The electric and magnetic field configuration of the quadrupole resonator are dependent on the excited mode. It is shown how this can be used to distinguish between electric and magnetic losses. PMID:22755638

Junginger, T; Weingarten, W; Welsch, C

2012-06-01

279

A 40 mm bore quadrupole magnet for the SSC  

SciTech Connect

A 40 mm bore quadrupole magnet design, called QC'', has been made for the SSC with the following parameters: 208 T/m gradient at 6500A, 2-layer cos 2 {theta}'' winding arrangement with 30 strand cable and one spacer wedge per coil. Structural support is provided by self-supporting interlocking collars; two types of symmetrical laminations are pre-assembled into collar packs for ease of assembly. This paper will describe the design of a prototype quadrupole magnet for the SSC and preliminary tests results on 1 m models. 7 refs., 6 figs., 2 tabs.

Taylor, C.E.; Barale, P.; Caspi, S.; Dell'Orco, D.; Fritz, D.; Gilbert, W.S.; Lietzke, A.; Peters, C.; Wandesforde, A.

1990-09-01

280

Induced beam oscillations from quadrupole vibrations in the SLC linac  

SciTech Connect

Linac beams in the Stanford Linear Collider (SLC) were driven into oscillation by transverse vibration of lattice quadrupoles at about 7 Hz. These quadrupoles are centered on 12-meter support girders located early in the linac. The vibrations were caused by ground motion at the 0.06 {mu}m level which was amplified in the accelerator supports up to 5 {mu}m. Seismic and support vibration measurements were Fourier analyzed and a strong correlation with beam observations was observed. Subsequent modifications of the supports have eliminated these oscillations.

Seeman, J.T.; Holtzapple, R.L.; Ross, M.C.

1993-06-01

281

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

282

Measurement of the Electric Quadrupole Moment of the 4d 2D5/2 Level in 88Sr+  

NASA Astrophysics Data System (ADS)

The quadrupole moment of the 4d 2D5/2 level in 88Sr+ has been measured to be 2.6(3)ea20, where a0 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 2S1/2 4d 2D5/2 transition at 674nm 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.

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

2004-09-01

283

A coil shape in superconducting quadrupole magnets for obtaining the perfect field  

NASA Astrophysics Data System (ADS)

A cos(2?) current distribution over a cylindrical surface gives an ideal quadrupolar field in so-called cos(2?) quadrupoles. A constant current in a coil configuration generated by two perpendicular intersecting ellipses also produces the perfect quadrupole field. We have found that an ideal quadrupole field can be obtained with a coil shape, different from the intersecting ellipses. Block-coil quadrupoles have been designed based on the coil shape as well as the intersecting ellipse shape.

Sarma, P. R.; Pattanayak, S. K.

2005-09-01

284

A coil shape in superconducting quadrupole magnets for obtaining the perfect field  

Microsoft Academic Search

A cos(2theta) current distribution over a cylindrical surface gives an ideal quadrupolar field in so-called cos(2theta) quadrupoles. A constant current in a coil configuration generated by two perpendicular intersecting ellipses also produces the perfect quadrupole field. We have found that an ideal quadrupole field can be obtained with a coil shape, different from the intersecting ellipses. Block-coil quadrupoles have been

P. R. Sarma; S. K. Pattanayak

2005-01-01

285

Quadrupole-collective states in a large single-j shell  

Microsoft Academic Search

We discuss the ability of the generator coordinate method (GCM) to select collective states in microscopic calculations. The model studied is a single-j shell with a Hamiltonian containing the quadrupole-quadrupole interaction. Quadrupole-collective excitations are constructed by means of the quadrupole single-particle operator. Lowest collective bands for j=31\\/2 and particle numbers N=4, 6, 8, 10, 12, and 14 are found. For

K. Burzynski; J. Dobaczewski

1995-01-01

286

Puff the magic dragon: How our understanding of fallout, residual and induced radiation evolved over fifty years of nuclear weapons testing  

Microsoft Academic Search

Radiobiological science has proceeded on empirical principles since health physics became a necessary professional adjunct to the military and civilian uses of nuclear energy in the aftermath of the detonations at Hiroshima and Nagasaki. This paper reviews the data which gradually emerged indicating that early assumptions about the detonation of atomic and nuclear weapons underestimated the significance of fallout, residual

Sue Rabbitt Roff

1998-01-01

287

Joint TNT and RDX detection via quadrupole resonance  

Microsoft Academic Search

Quadrupole resonance (QR) technology has been receiving increasing attention for explosive detection in applications including landmine detection. It can be used as a confirming sensor for buried plastic landmine detection by detecting the explosives within the mine. Since a single mine can contain more than one type of explosives (e.g., trinitrotoluene (TNT) and (RDX) compound), a detector designed to detect

Hong Xiong; Jian Li; GEOFFREY A. BARRALL

2007-01-01

288

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.

289

Tune Shift with Amplitude Induced by Quadrupole Fringe Fields  

Microsoft Academic Search

Using Lie algebra techniques, we derive an analytical expression for the nonlinear Hamiltonian and the linear tune shift with amplitude due to quadrupole fringe fields. Numerical examples for the FNAL muon storage ring is compared with results from the computer code COSY INFINITY.

Frank Zimmermann

2000-01-01

290

Single layer quadrupole design for SSC (Superconducting Super Collidar)  

Microsoft Academic Search

The proposed Superconducting Super Collider (SSC) will require 1360 regular arc quadrupoles. This paper describes a single layer design for these magnets. This design is economically competitive with the more conventional two layer design and appears to be well suited to mass production because of its simplicity. The design uses 9 turns of Cu(NbTi) superconducting cable to produce an 155

P. A. Thompson; J. Cottingham; P. Dahl; M. Garber; A. Ghosh; C. Goodzeit; A. Greene; H. Hahn; J. Herrera; S. Kahn

1987-01-01

291

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

292

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

293

Kick Velocity Induced by Magnetic Dipole and Quadrupole Radiation  

Microsoft Academic Search

We examine the recoil velocity induced by the superposition of magnetic dipole and quadrupole radiation from a pulsar\\/magnetar born with rapid rotation. The resultant velocity depends on not the magnitude, but rather the ratio of the two moments and their geometrical configuration. The model does not necessarily lead to high spatial velocity for a magnetar with a strong magnetic field,

Yasufumi Kojima; Yugo E. Kato

2011-01-01

294

Microfabricated Quadrupole Mass Spectrometer With a Brubaker Prefilter  

Microsoft Academic Search

Microfabricated quadrupole mass spectrometers with Brubaker prefilters are demonstrated for the first time. Complete filters are assembled from two dies, each carrying two pairs of rods providing the prefilter and main filter sections. The rods are held in precision silicon mounts that are fabricated using wafer-scale deep reactive-ion etching and anodic bonding to glass substrates. Improvements to ion transmission are

Steven Wright; Shane O'Prey; Richard R. A. Syms; Guodong Hong; Andrew S. Holmes

2010-01-01

295

Dominance of monopole and quadrupole pairs in the Nilsson model  

SciTech Connect

The intrinsic state of the Nilsson model is analyzed in terms of nucleon pairs coupled to spins 0/sup +/, 2/sup +/, 4/sup +/, 6/sup +/, ... . It is shown that 0/sup +/ and 2/sup +/ pairs dominate the Cooper pair which constitutes the intrinsic state with large quadrupole deformation.

Otsuka, T.; Arima, A.; Yoshinaga, N.

1982-02-08

296

Couplings between dipole and quadrupole vibrations in tin isotopes  

SciTech Connect

We study the couplings between collective vibrations such as the isovector giant dipole and isoscalar giant quadrupole resonances in tin isotopes in the framework of the time-dependent Hartree-Fock theory with a Skyrme energy density functional. These couplings are a source of anharmonicity in the multiphonon spectrum. In particular, the residual interaction is known to couple the isovector giant dipole resonance with the isoscalar giant quadrupole resonance built on top of it, inducing a nonlinear evolution of the quadrupole moment after a dipole boost. This coupling also affects the dipole motion in a nucleus with a static or dynamical deformation induced by a quadrupole constraint or boost, respectively. Three methods associated with these different manifestations of the coupling are proposed to extract the corresponding matrix elements of the residual interaction. Numerical applications of the different methods to {sup 132}Sn are in good agreement with each other. Finally, several tin isotopes are considered to investigate the role of isospin and mass number on this coupling. A simple 1/A dependence of the residual matrix elements is found with no noticeable contribution from the isospin. This result is interpreted within the Goldhaber-Teller model.

Simenel, C.; Chomaz, Ph. [CEA, Centre de Saclay, IRFU/Service de Physique Nucleaire, F-91191 Gif-sur-Yvette (France); CEA, Centre de Saclay, IRFU/Dir, F-91191 Gif-sur-Yvette (France) and GANIL (DSM-CEA/IN2P3-CNRS), Boite Postale 55027, F-14076 Caen cedex 5 (France)

2009-12-15

297

Hybrid quadrupole excitons and polaritons in cuprous oxide  

NASA Astrophysics Data System (ADS)

In this thesis I consider novel type of materials such as hybrid organic/inorganic heteoro-structures and polystyrene micro-spheres/inorganic composites. The organic/inorganic compound is presented by DCM2:CA:PS/cuprous oxide material. Using "solid state solvent" mechanism I propose to bring the Frenkel exciton (FE) of the DCM2 into resonance with 1S quadrupole Wanier-Mott exciton (WE) in cuprous oxide. This two types of the excitons form new type of quadrupole-dipole hybrid exciton. This hybrid is characterized by long lifetime and big oscillator strength inherited from the organic FE. In the part I of the thesis I investigate the enhancement of the quadrupole properties generic to cuprous oxide exciton by means of such resonant hybridization. I consider enhancement of photo-thermal bi-stability and second harmonic generation. The second part is devoted to the problems of light-matter interaction in cuprous oxide crystals such as weak interaction with LA phonons and whispering gallery modes (WGM) in adjacent layer of polystyrene micro-spheres. While the first effect is likely to impeded BEC of the polaritons, the second mechanism provides necessary temporal coherence. It is possible by trapping the light part of the polariton into resonant WGM through big gradient of the evanescent tail which provides big lifetime of such evanescent polariton. Due to big gradient of the evanescent field it couples "naturally" to the quadrupole WE in cuprous oxide.

Roslyak, Oleksiy

298

The ground state and the isoscalar giant quadrupole resonance of 40Ca  

NASA Astrophysics Data System (ADS)

The ground state and the isoscalar giant quadrupole resonance (ISGQR) properties in the 40Ca are calculated in the framework of the Higher Tamm Dancoof Approximation noted as (HTDA), using the residual interaction the delta (?) plus quadrupole-quadrupole (QQ) interaction.

Naïdja, H.; Quentin, P.

2012-06-01

299

Calculation of surface quadrupole field, polarization, and pyroelectricity for anthracene and pyrene crystals  

Microsoft Academic Search

Surface quadrupole tensor sums have been calculated for unrelaxed (001), (010), and (100) surfaces of anthracene and pyrene, with the molecules treated as points. The surface has most effect on sums relating molecules in different surface layers. With the molecular quadrupole moments, the quadrupole sums give the surface electric fields, which reach 5 GV m?1 for anthracene and 15 GV

A. J. Gill; R. W. Munn

1994-01-01

300

Production techniques for the superconducting super collider low energy booster quadrupole magnet  

Microsoft Academic Search

The manufacturing techniques used for a prototype quadrupole magnet, developed at Lawrence Berkeley Laboratory (LBL) for the Superconducting Super Collider (SSC) Low Energy Booster (LEB), are described. The SSC LEB Ring employs 96 dipoles and 90 quadrupoles connected in series to form the magnetic lattice, requiring the use of a 21.9 mm x 23.0 mm hollow conductor for the quadrupoles.

Michael E. Morrison; Gerd U. Behrsing; Robert L. Fulton

1994-01-01

301

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

302

Development of Quadrupole, Steering and Corrector Magnets for the SIS 300  

Microsoft Academic Search

In the frame of collaboration in the FAIR project IHEP has developed a design of a fast cycling quadrupole, which will be assembled together with corrector magnets in the united cryostat. This quadrupole is intended as the main unit for the SIS 300 ring. The 1-layer coil of the quadrupole is divided in three blocks and will be wound by

L. Tkachenko; I. Bogdanov; S. Kozub; P. Shcherbakov; V. Sytnik; A. Tchikilev; V. Zubko

2010-01-01

303

Operational studies and expected performance of superconducting quadrupole magnets in the first stages of secondary beams  

Microsoft Academic Search

A low current, large bore, epoxy impregnated superconducting quadrupole magnet was constructed as a possible prototype for secondary beam use. Beam quenching tests were performed by targetting a primary proton beam directly onto the quadrupole coil and by using the quadrupole in its anticipated role as part of the first stage flux collection triplet for a zero degree anti-proton secondary

P. H. Garbincius; P. O. Mazur; R. P. Stanek; R. P. Smith; S. H. Kim; C. I. Krieger; J. D. Gonczy; A. L. Kelly; D. C. Underwood; E. J. Wallace

1983-01-01

304

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

305

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

306

Quantum Effect in Enhanced Nuclear Magnets  

Microsoft Academic Search

Effective nuclear Hamiltonian is derived by using the canonical transformation to study enhanced nuclear magnets. The system described by it is the Heisenberg model reflecting the symmetry of the crystal field states. The exchange interaction and pseudo-quadrupole energy turn anisotropic for non-cubic crystals. In various cases this makes the magnetization incommutable with the Hamiltonian and brings quantum effect. The system

Hiroumi Ishii; Shingo Aoyama

1991-01-01

307

Quadrupole radiation from terahertz dipole antennas.  

PubMed

We report what is to our knowledge the first detailed investigation of the polarization state of radiation from lens-coupled terahertz dipole antennas. The radiation exhibits a weak but measurable component that is polarized orthogonally to the orientation of the emitter dipole. The angular radiation pattern of this cross-polarized emission reveals that it is quadrupolar, rather than dipolar, in nature. One can understand this result by taking into account the photocurrent flowing in the strip lines that feed the dipole antenna. A Fresnel-Kirchhoff scalar diffraction calculation is used for calculating the frequency-dependent angular distribution of the radiation pattern, providing satisfactory agreement with the measurements. PMID:18066277

Rudd, J V; Johnson, J L; Mittleman, D M

2000-10-15

308

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

309

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

310

Understanding Chemotherapy  

MedlinePLUS

... with your doctor or nurse. I am getting chemo to: _____________________ _____________________ _____________________ _____________________ _____________________ _____________________ _____________________ _____________________ Check with your doctor or nurse before ... or nurse. This is how I will get chemo: _____________________ _____________________ _____________________ _____________________ _____________________ _____________________ _____________________ _____________________ Understanding Chemotherapy When will I get chemotherapy? You ...

311

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 ...

312

Measurements of field decay and snapback effect on Tevatron dipole and quadrupole magnets  

SciTech Connect

Since the beginning of 2002 an intensive measurement program has been performed at the Fermilab Magnet Test Facility (MTF) to understand dynamic effects in Tevatron magnets. Based on the results of this program a new correction algorithm was proposed to compensate for the decay of the sextupole field during the dwell at injection and for the subsequent field ''snapback'' during the first few seconds of the energy ramp. Beam studies showed that the new correction algorithm works better than the original one, and improves the Tevatron efficiency by at least 3%. The beam studies also indicated insufficient correction during the first 6s of the injection plateau where an unexpected discrepancy of 0.15 sextupole units of extra drift was observed. This paper reports on the most recent measurements of the Tevatron dipoles field at the beginning of the injection plateau. Results on the field decay and snapback in the Tevatron quadrupoles are also presented.

Velev, G.V.; Ambrosio, G.; Annala, G.; Bauer, P.; Carcagno, R.; DiMarco, J.; Glass, H.; Hanft, R.; Kephart, R.; Lamm, M.; Martens, M.; Schlabach, P.; Sylvester, C.; Tartaglia, M.; Tompkins, J.; /Fermilab

2005-05-01

313

Two-dimensional magnetic sensitivity to asymmetric and symmetric deviations for SSC quadrupole magnets  

NASA Astrophysics Data System (ADS)

The magnetic multipole sensitivity to asymmetric and symmetric deviations is analyzed in the two-dimensional cross-section of SSC quadrupole magnets. Deviations in the 2-D cross-section caused by variations in the superconducting cable locations due to changes in the thickness of the pole sheet, mid plane insulation, inter-layer spacer, backing sheet, and copper wedges have direct impact on the magnetic field gradient and multipoles in the straight section of the magnets. Asymmetric deviations due to different coil sizes in a cross-section are also analyzed. The analyses are performed mainly with the software package AHARM(1). SSCMAG(1) and finite element software PE2D(2) were also used to obtain baselines and to verify the results. The results provide information essential to an understanding of the deviations of the multipoles resulting from manufacturing processes, and suggest possibilities for tuning the multipoles to meet the magnetic requirements.

Xu, Minfeng; Waynert, Joseph A.

1994-07-01

314

A Quadrupole Band-Pass Filter for a White Proton Source  

NASA Astrophysics Data System (ADS)

The LANSCE facility at Los Alamos National Laboratory uses a beam of 800 MeV protons as a source of continuous (white) beams of neutrons, used for a wide range of basic and applied science. The same source also provides a white source of protons, which would be very useful for research, if some degree of energy resolution were available. We are designing a quadrupole magnet system that will provide such energy resolution by focusing only the desired momentum onto a sample, with protons of more or less momentum more widely diffused. Results will be given for designs based on simple thin lens optics to understand the criteria and general trends. A full design will require use of magnetic beam transport codes and a specific magnet system.

Morrow, Jonathon; Peterson, Jerry

2009-10-01

315

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

316

Permanent-magnet quadrupoles in an RFQ linacs  

SciTech Connect

We investigated the possibility of increasing the current-carrying capability of radio-frequency quadrupole (RFQ) linear accelerators by adding permanent-magnet quadrupole (PMQ) focusing to the existing transverse focusing provided by the rf electric field. Increased transverse focusing would also allow shortening RFQ linacs by permitting a larger accelerating gradient, which is normally accomplished by an undesirable increased transverse rf defocusing effect. We found that PMQs were not helpful in increasing the transverse focusing strength in an RFQ. This conclusion was reached after some particle tracing simulations and some analytical calculations. In our parameter regime, the addition of the magnets increases the betatron frequency but does not result in improved focusing because the increased flutter more than offsets the gain from the increased betatron frequency.

Lysenko, W.P.; Wang, T.F.

1985-01-01

317

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

318

Quadrupole moments of wobbling excitations in 163Lu  

SciTech Connect

Lifetimes of states in the triaxial strongly deformed bands of {sup 163}Lu have been measured in a Gammasphere experiment using the Doppler-shift attenuation method. The bands are interpreted as wobbling-phonon excitations from the characteristic electromagnetic properties of the transitions connecting the bands. Quadrupole moments were extracted for the 0-phonon yrast band and, for the first time, for the 1-phonon wobbling band. The very similar results found for both bands suggest a similar intrinsic structure confirming the wobbling interpretation. While the in-band quadrupole moments for the bands show a decreasing trend towards higher spin, the strength of the inter-band transitions remains constant. Both features can be understood by a small increase in triaxiality towards higher spin. Such a change in triaxiality is also found in cranking calculations, to which the experimental results are compared.

Gorgen, A.; Clark, R.M.; Cromaz, M.; Fallon, P.; Hagemann, G.B.; Hubel, H.; Lee, I.Y.; Macchiavelli, A.O.; Sletten, G.; Ward, D.; Bengtsson, R.

2004-01-01

319

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

320

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

321

Test results of LHC interaction regions quadrupoles produced by Fermilab  

SciTech Connect

The US-LHC Accelerator Project is responsible for the production of the Q2 optical elements of the final focus triplets in the LHC interaction regions. As part of this program Fermilab is in the process of manufacturing and testing cryostat assemblies (LQXB) containing two identical quadrupoles (MQXB) with a dipole corrector between them. The 5.5 m long Fermilab designed MQXB have a 70 mm aperture and operate in superfluid helium at 1.9 K with a peak field gradient of 215 T/m. This paper summarizes the test results of several production MQXB quadrupoles with emphasis on quench performance and alignment studies. Quench localization studies using quench antenna signals are also presented.

Bossert, R.; Carson, J.; Chichili, D.R.; Feher, S.; Kerby, J.; Lamm, M.J.; Nobrega, A.; Nicol, T.; /Fermilab; Ogitsu, T.; /KEK, Tsukuba; Orris, D.; Page, T.; Peterson, T.; Rabehl, R.; Robotham, W.; /Fermilab; Scanlan, R.; /LBL, Berkeley; Schlabach, P.; Sylvester, C.; Strait, J.; Tartaglia, M.; Tompkins, J.C.; Velev, G.; /Fermilab

2004-10-01

322

SKEW QUADRUPOLES IN RHIC DIPOLE MAGNETS AT HIGH FIELDS.  

SciTech Connect

In the RHIC arc dipoles, the center of the cold mass lies above the center of the cryostat. At the maximum design field, the magnetic flux lines leak through the yoke to the asymmetrically located cryostat, which provides an additional return path. This introduces a systematic top-bottom asymmetry leading to a skew quadrupole term at high fields. A similar asymmetry is also created by any difference in weights of the upper and the lower yoke halves. Data from measurements of several RHIC dipoles are presented to study this effect. In the current production series of the RDIC dipoles, an attempt is made to compensate the effect of the cryostat by an asymmetry in the iron yoke. Seven dipoles with this type of yoke have been cold tested, and show a reduced saturation in the skew quadrupole term, as expected.

JAIN, A.; GUPTA, P.; THOMPSON, P.; WANDERER, P.

1995-06-11

323

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

324

Design and Measurement of the NSLS II Quadrupole Prototypes  

SciTech Connect

The design and measurement of the NSLS-II ring quadrupoles prototypes are presented. These magnets are part of a larger prototype program described in [1]. Advances in software, hardware, and manufacturing have led to some new level of insight in the quest for the perfect magnet design. Three geometric features are used to minimize the first three allowed harmonics by way of optimization. Validations through measurement and confidence levels in calculations are established.

Rehak,M.; Jain, A. K.; Skaritka, J.; Spataro, C.

2009-05-04

325

Quadrupole shape invariants in the interacting boson model  

NASA Astrophysics Data System (ADS)

In terms of the interacting boson model (IBM), shape invariants for the ground state, formed by quadrupole moments up to sixth order, are studied in the dynamical symmetry limits and over the whole structural range of the IBM-1. The results are related to the effective deformation parameters and their fluctuations in the geometrical model. New signatures that can distinguish vibrator and ?-soft rotor structures, and one that is related to shape coexistence, are identified.

Werner, V.; Pietralla, N.; von Brentano, P.; Casten, R. F.; Jolos, R. V.

2000-02-01

326

Magnetic performance of new Fermilab high gradient quadrupoles  

SciTech Connect

For the Fermilab Tevatron low beta insertions installed in 1990--1991 as part of a luminosity upgrade there were built approximately 35 superconducting cold iron quadrupoles utilizing a two layer cos 2{theta} coil geometry with 76 mm diameter aperature. The field harmonics and strengths of these magnets obtained by measurement at cryogenic conditions are presented. Evidence for a longitudinal periodic structure in the remnant field is shown. 6 refs., 2 figs., 3 tabs.

Hanft, R.; Brown, B.C.; Carson, J.A.; Gourlay, S.A.; Lamm, M.J.; McInturff, A.D.; Mokhtarani, A.; Riddiford, A.

1991-05-01

327

THERMAL FLUID MODELING OF BEPCII IR QUADRUPOLE MAGNET CRYOSTAT.  

SciTech Connect

A pair of superconducting interaction region quadrupole magnets for BEPCII was designed and fabricated at Brookhaven National Laboratory, USA. The cryogenic system for the IR magnets was designed at Harbin Institute of Technology, China. This paper provides the results of thermal fluid modeling for the magnet cryostat. The numerical analyses were carried out for two types of cooling methods, the subcooled liquid helium and the supercritical helium flow. The pressure and temperature changes in the cooling circuits are given.

WANG.L.; TANG,H.M.; ZHANG,X.B.; YANG,G.D.; JIA,L.X.

2004-05-11

328

A superconducting iron-dominated quadrupole for CEBAF  

Microsoft Academic Search

The present design for the high-resolution spectrometers at CEBAF requires a front quadrupole (QO) that has a gradient x length of 6.8 T with a good field aperture (1x10⁻⁸ uniformity in gradient) of 16 cm radius. A room temperature design was found too power hungry and interfered with the beam. Engineering and construction of a small cos 2theta magnet was

Leigh Harwood; Steve Lassiter; Walter Tuzel

1989-01-01

329

Spontaneous'' cluster decomposition in a quadrupole ion trap  

SciTech Connect

Cluster ions normally found in high pressure ion sources are not usually observed under chemical ionization conditions in the quadrupole ion trap. This is mainly due to the lower pressures in the ion trap which affect third body stabilization. But, even for cluster ions injected from an external source, decomposition is observed. By injecting cluster ions of known stability and measuring the decomposition rate as a function of pressure and time, we can determine what affects various parameters have on the internal ion temperatures in the quadrupole ion trap. The desolvation experiments were carried out by injecting ions formed via electrospray into the quadrupole ion trap. The atmospheric sampling glow discharge ionization (ASGDI) source served as the interface between atmosphere and the vacuum chamber. Protonated water clusters were formed by spraying distilled water at a flow rate of 1 uL/min and protonated methanol clusters were formed by spraying HPLC grade methanol at 1 uL/min. Since fragmentation of ions upon injection into an ion trap has been observed in our lab as well as others, we needed to determine if ions are excited'' during injection. Therefore, the cluster ion mass spectra from the ion trap was compared to the cluster ion mass spectra from a quadrupole mass filter using the same interface and electrospray conditions. The results showed that, under the ion injection conditions used in this study for both the water and methanol clusters, significant internal excitation did not occur during injection. The clusters, therefore, acquired the necessary energy for dissociation after they were trapped. 3 refs., 3 figs., 1 tab.

Asano, K.G.; McLuckey, S.A.; Glish, G.L. (Oak Ridge National Lab., TN (USA)); Bartmess, J.E. (Tennessee Univ., Knoxville, TN (USA). Dept. of Chemistry)

1991-01-01

330

Longitudinal capture in the radio-frequency-quadrupole structure  

SciTech Connect

The radio-frequency-quadrupole (RFQ) linac structure not only can attain easily transverse focusing in the low-beta region, but also can obtain very high capture efficiency because of its low beta-lambda and low-particle rigidity. An optimization study of the zero space-charge longitudinal capture in an RFQ linac that yields configurations with large capture efficiency is described.

Inagaki, S.

1980-03-01

331

Analysis on linac quadrupole misalignment in FACET commissioning 2012  

SciTech Connect

In this note, the analysis on linac quadrupole misalignment is presented for the FACET linac section LI05-09 plus LI11-19. The effectiveness of the beam-based alignment technique is preliminarily confirmed by the measurement. Beam-based alignment technique was adopted at SLAC linac since SLC time. Here the beam-based alignment algorithms are further developed and applied in the FACET commissioning during 2012 run.

Sun, Yipeng; /SLAC

2012-07-05

332

Radio frequency quadrupole linac for the superconducting super Collider  

Microsoft Academic Search

A 2.5 MeV, 428 MHz radio frequency quadrupole (RFQ) linac has been designed and fabricated by the Los Alamos National Laboratory and GAR Electroforming for the Superconducting Super Collider Laboratory. This device is a two segment accelerator fabricated from tellurium-copper (CDA14500) vane\\/cavity quadrants which are joined by electroforming. The structure incorporates an integral vacuum jacket and has no longitudinal rf

D. L. Schrage; L. M. Young; W. L. Clark; J. H. Billen; R. F. Depaula; A. C. Naranjo; G. H. Neuschaefer; P. L. Roybal; J. E. Stovall; K. Ray; R. Richter

1993-01-01

333

Kick velocity induced by magnetic dipole and quadrupole radiation  

Microsoft Academic Search

We examine the recoil velocity induced by the superposition of the magnetic\\u000adipole and quadrupole radiation from a pulsar\\/magnetar born with rapid\\u000arotation. The resultant velocity depends on not the magnitude, but rather the\\u000aratio of the two moments and their geometrical configuration. The model does\\u000anot necessarily lead to high spatial velocity for a magnetar with a strong\\u000amagnetic

Yasufumi Kojimaand; Yugo E. Kato

2010-01-01

334

Development of quadrupole mass spectrometers using rapid prototyping technology  

Microsoft Academic Search

In this report, we present a prototype design of a quadrupole mass filter (QMF) with hyperbolic electrodes, fabricated at\\u000a the University of Liverpool using digital light processing (DLP), a low-cost and lightweight 3D rapid prototyping (RP) technique.\\u000a Experimental mass spectra are shown for H2+, D2+, and He+ ions to provide proof of principle that the DLP mass filter is working

Boris Brki?; Neil France; Adam T. Clare; Chris J. Sutcliffe; Paul R. Chalker; Stephen Taylor

2009-01-01

335

Quadrupole shape invariants in the interacting boson model  

SciTech Connect

In terms of the interacting boson model (IBM), shape invariants for the ground state, formed by quadrupole moments up to sixth order, are studied in the dynamical symmetry limits and over the whole structural range of the IBM-1. The results are related to the effective deformation parameters and their fluctuations in the geometrical model. New signatures that can distinguish vibrator and {gamma}-soft rotor structures, and one that is related to shape coexistence, are identified. (c) 2000 The American Physical Society.

Werner, V. [Institut fuer Kernphysik, Universitaet zu Koeln, 50937 Koeln, (Germany); Pietralla, N. [Institut fuer Kernphysik, Universitaet zu Koeln, 50937 Koeln, (Germany); Brentano, P. von [Institut fuer Kernphysik, Universitaet zu Koeln, 50937 Koeln, (Germany); Casten, R. F. [Wright Nuclear Structure Laboratory, Yale University, New Haven, Connecticut 06520-8124 (United States); Jolos, R. V. [Institut fuer Kernphysik, Universitaet zu Koeln, 50937 Koeln, (Germany); Bogoliubov Laboratory, Joint Institute for Nuclear Research, 141980 Dubna, Russia (Russian Federation)

2000-02-01

336

Quadrupole-moments in mirror nuclei and proton halo  

Microsoft Academic Search

Electric quadrupole moments in light mirror nuclei are studied by shell model calculations with the proton-neutron formalism. Our calculations describe successfully the Q-moments of both loosely-bound and well-bound nuclei. The adopted effective charges are consistent with the theoretical predictions due to the core polarization effect. The large enhancement in 8B and 17F shows a clear evidence of the proton halos.

Hisashi Kitagawa; Hiroyuki Sagawa

1993-01-01

337

Propagation Hanle effect of quadrupole polaritons in Cu2O  

Microsoft Academic Search

A generalized theory of the Hanle effect is developed for the case of propagation quantum beats. Time-integrated quantum beats of two polariton wave packets with the same group velocities and polarizations belonging to two different Zeeman components in Voigt geometry of the quadrupole-active ortho-exciton Gamma+5 level in Cu2O crystal give rise to the propagation Hanle effect. It is characterized by

S. A. Moskalenko; M. A. Liberman

2002-01-01

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

Electrostatic quadrupole array for focusing parallel beams of charged particles  

DOEpatents

An array of electrostatic quadrupoles, capable of providing strong electrostatic focusing simultaneously on multiple beams, is easily fabricated from a single array element comprising a support rod and multiple electrodes spaced at intervals along the rod. The rods are secured to four terminals which are isolated by only four insulators. This structure requires bias voltage to be supplied to only two terminals and eliminates the need for individual electrode bias and insulators, as well as increases life by eliminating beam plating of insulators.

Brodowski, John (Smithtown, NY)

1982-11-23

340

Understanding Science  

NSDL National Science Digital Library

This page, from University of California Museum of Paleontology, features free, image-rich teaching resources that communicate what science is and how it works, with a focus on the process of science and its dynamic nature. The project is geared toward K-16 teacher preparation as well as broader public understanding of the nature of science.

Paleontology, University O.

341

Understanding Suicide  

Microsoft Academic Search

Because suicide has become a significant public health concern in the United States (and internationally), occupational therapists who work with psychiatric populations-particularly adolescent and geriatric populations-should enhance their understanding of suicidal behavior, their ability to assess suicidal ideology in patients, and their awareness of effective prevention and treatment methods. This paper reviews the demography, risk factors, and biological underpinnings of

Sharon A. Gutman

2005-01-01

342

Understanding Prejudice.  

ERIC Educational Resources Information Center

|To help students understand prejudice, teachers in Verona, New York, planned a unit which incorporated the use of fiction, television, and film. Students were asked to select and read books in the general area of prejudice. A sample reading list of works under the headings of Negro, Jew, Italian, and Irish was provided. After writing extensive…

Babcock, David

1967-01-01

343

Understanding Autism  

Microsoft Academic Search

Although much is known about autism, misconceptions persist. A case report is presented and used as a framework for dispelling some common myths about the condition. A simple, practical model for understanding autism is proposed and recommendations are provided for the practitioner managing a child with autistic-like features.

Jon Matthew Farber; Arnold J. Capute

1984-01-01

344

Understanding Tides.  

National Technical Information Service (NTIS)

This book presents an elementary explanation of tides and tidal datums. It is written to explain the natural phenomenon of tides in terms and concepts readily understandable by students as well as those in all walks of life merely wishing to be enriched b...

S. Dopp-Hicks

2006-01-01

345

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

346

Understanding Prejudice.  

ERIC Educational Resources Information Center

To help students understand prejudice, teachers in Verona, New York, planned a unit which incorporated the use of fiction, television, and film. Students were asked to select and read books in the general area of prejudice. A sample reading list of works under the headings of Negro, Jew, Italian, and Irish was provided. After writing extensive…

Babcock, David

1967-01-01

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…

Milburn, Val

348

Understanding the \\  

Microsoft Academic Search

Study of personality type has contributed a lot to our understanding and prediction of human behaviour, especially in organizational contexts. A great deal of interest is especially focused on what types of people are most effective in different management environments. This study aimed to identify differences in psychological types of management students and business executives using the Myers-Briggs Type Indicator

Desai Tejas A; Kirti Sharda

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

The effect of elastic properties of nuclear matter on nuclear fission  

Microsoft Academic Search

Spheroidal nuclear vibrations are considered using a macroscopic model based on the assumption that nuclear matter possesses the properties of elastic medium. Emphasis is laid on the analysis of instability of the quadrupole configuration. It is presumed that the onset of this instability is associated with the commencement of fission. The proposed fluid-dynamics model predicts the values of the parameters

S. I. Bastrukov; I. V. Molodtsova; E. Kh. Yuldashbaeva

1994-01-01

351

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

352

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

353

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.

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

2013-01-01

354

Understanding Sexuality  

Microsoft Academic Search

\\u000a Chapter 3 provides readers with an explanation of the issues related to sexuality in schools. The first section defines sexual\\u000a orientation, behavior, and identity and several related terms that are important for education professionals to understand.\\u000a The second section explores contemporary youth sexualities and some of the various identities embraced by youth today. The\\u000a third section gives a brief history

Elizabeth J. Meyer

355

Understanding parisians  

Microsoft Academic Search

The urban physical environment results not only from functional requirements of urban life, but also from the very cultural\\u000a background and social relationships. After examining the relationships between the architecture and the cultural contexts\\u000a in Paris, the author presents and argues a belief that the architectural characteristics in Paris can be better explained\\u000a by understanding the Parisian ways of urban

Hua Chen

2000-01-01

356

Understanding Torque  

NSDL National Science Digital Library

This website, presented by the University of Guelph, is a tutorial on understanding torque associated with mechanical equipment. It includes example problems, definitions and self-tests. The site combines images, diagrams and text to present its concepts. Overall, the website is easy to use and provides solid information about the topic. It is a great resource for students and instructors in a technical classroom.

2008-10-28

357

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

358

139La nuclear magnetic resonance characterisation of La2O3 and La1-xSrxMO3 where M = Cr, Mn or Co.  

PubMed

139La Nuclear magnetic resonance (NMR) spectra have been used to obtain nuclear quadrupole coupling parameters for La2O3 and a series of perovskites La1-xSrxMO3 (where M = Cr, Mn or Co). Depending on the doping level of SrO2 these materials are either paramagnetic or ferromagnetic at room temperature. Magnetic transferred hyperfine effects are strongly in evidence in the Mn compounds. A 59Co NMR spectrum was observed in LaCoO3. A precision measurement of the nuclear quadrupole coupling constant in La2O3 was made by nuclear quadrupole resonance (NQR) spectroscopy. PMID:7827974

Bastow, T J

1994-02-01

359

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

360

TESTING OF NB{sub 3}SN 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. J.; Novitski, I.; Tartaglia, M.; Tompkins, J. C.; Turrioni, D.; Yamada, R. [Fermi National Accelerator Laboratory, Batavia, IL, 60510 (United States)

2010-04-09

361

Understanding resilience.  

PubMed

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

2013-02-15

362

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

363

Understanding Ayurveda  

PubMed Central

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.

Gadgil, Vaidya Dilip

2010-01-01

364

Third-order spherical aberration correction using multistage self-aligned quadrupole correction-lens systems.  

PubMed

New multistage self-aligned quadrupole correction-lens systems are proposed for correcting the spherical aberration of a rotationally symmetrical lens in a probe-forming system such as electron beam lithography and focused ion beam. These multistage correction-lens systems consist of six- or eight-stage electrostatic quadrupole and aperture electrodes placed between the quadrupoles. An octupole field for the correction of aperture aberration is automatically created and aligned with a quadrupole field by supplying a voltage to the aperture electrode. The optical properties of the self-aligned quadrupole correction-lens systems are precisely simulated using the potential functions approximated from the calculated three-dimensional potential distributions. The lens components of the correction-lens systems are symmetric with respect to the mid-plane of the correction system, and the quadrupole excitations are anti-symmetric to the mid-plane. The simulated optical properties of the six- and eight-stage self-aligned quadrupole correction-lens systems are compared with a four-stage self-aligned quadrupole correction-lens system. Aperture aberration coefficients of the six- or eight-stage quadrupole system under non-excitation of the aperture electrodes become much smaller than those of the four-stage quadrupole system. It is found that the correction of spherical aberration using the six- or eight-stage self-aligned quadrupole correction-lens system can be easily achieved under the condition of considerably lower excitation of lens elements in comparison to the four-stage self-aligned quadrupole correction-lens system. PMID:20086186

Tamura, Keiji; Okayama, Shigeo; Shimizu, Ryuichi

2010-01-19

365

Quadrupole effects in /sup 7/Li scattering at 88 MeV  

SciTech Connect

Calculations for /sup 7/Li elastic scattering at 88 MeV have been made explicitly including a quadrupole term in the optical potential resulting from folding of an effective nucleon-nucleon interaction with the quadrupole deformation of /sup 7/Li. Data for /sup 48/Ca could be fitted without a renormalization of the folded potential, but this was not possible for lighter targets which required a renormalization of about 0.6 even when the quadrupole potential was included.

Cook, J.; Vineyard, M.F.; Kemper, K.W.; Hnizdo, V.

1983-04-01

366

Production techniques for the Superconducting Super Collider Low Energy Booster quadrupole magnet  

Microsoft Academic Search

The manufacturing techniques used for a prototype quadrupole magnet, developed at Lawrence Berkeley Laboratory (LBL) for the Superconducting Super Collider (SSC) Low Energy Booster (LEB), are described. The SSC LEB Ring employs 96 dipoles and 90 quadrupoles connected in series to form the magnetic lattice, requiring the use of a 21.9 mm×23.0 mm hollow conductor for the quadrupoles. Due to

M. E. Morrison; G. U. Behrsing; R. L. Fulton

1994-01-01

367

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

368

Quadrupole moment and a proton halo structure in 17F (Ipi = 5\\/2+)  

Microsoft Academic Search

The quadrupole moment of light nuclei 17F in the ground state (Ipi = 5\\/2+) is measured by the beta-NMR method. The effective charge of the last proton in a d5\\/2 orbit for 17F is extracted from the measured quadrupole moment Q(17F) divided by the quadrupole moment Qsp calculated with a single particle model. A proton effective charge of eeffp =

Zhou Dongmei; Zheng Yongnan; Yuan Daqing; Zhang Xizhen; Zuo Yi; T. Minamisono; M. Matsuta; M. Fukuda; M. Mihara; Zhang Chunlei; Wang Zhiqiang; Du Enpeng; Luo Hailong; Xu Guoji; Zhu Shengyun

2007-01-01

369

Comprehensive two-dimensional gas chromatography—quadrupole mass spectrometric analysis of drugs  

Microsoft Academic Search

The use of comprehensive two-dimensional gas chromatography coupled to quadrupole mass spectrometry (GC × GC–qMS) for drug screening is investigated with 77 underivatised drug standards in methanolic solution. The GC × GC–qMS setup involved a reduced mass scan range of 42–235u and minimum quadrupole sampling time to achieve quadrupole scanning frequency of 19.36Hz. Only 26% of the drugs investigated gave

Shin Miin Song; Philip Marriott; Paul Wynne

2004-01-01

370

An Application of 3-D MEMS Packaging: Out-of-Plane Quadrupole Mass Filters  

Microsoft Academic Search

This paper reports the design, fabrication, and characterization of low-cost out-of-plane quadrupole mass filters that use commercially available dowel pins as electrode rods. The quadrupoles implement a 3-D MEMS packaging technology that relies on deep-reactive ion etching (DRIE)-patterned deflection springs for alignment. Quadrupoles with rod diameter ranging from 0.25 to 1.58 mm and aspect ratio of 30 to 60 were

Luis F. Velasquez-Garcia; Kerry Cheung; Akintunde I. Akinwande

2008-01-01

371

Orientational order of solutes in liquid crystals: The effect of distributed electric quadrupoles  

NASA Astrophysics Data System (ADS)

We perform Monte Carlo simulations of a mixture of soft ellipsoids with embedded quadrupoles as a model of various small molecules dissolved in nematic liquid crystals. We find that Gay-Berne ellipsoids with distributed embedded quadrupoles qualitatively reproduce the trend in the order parameters observed experimentally in NMR spectra. In contrast, ellipsoids with a single embedded quadrupole cannot reproduce the negative order parameter of acetylene in EBBA.

Lee, J. S. J.; Sokolovskii, R. O.; Berardi, R.; Zannoni, C.; Burnell, E. E.

2008-03-01

372

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

373

[Electromagnetic studies of nuclear structure and reactions]. [Nuclear Physics Group, Univ. of New Hampshire  

SciTech Connect

The experimental goals are focused on developing an understanding of strong interactions and the structure of hadronic systems by determination of the electromagnetic response; these goals will be accomplished through coincidence detection of final states. Nuclear modeling objectives are to organize and interpret the data through a consistent description of a broad spectrum of reaction observables; calculations are performed in a nonrelativistic diagrammatic framework as well as a relativistic QHD approach. Work is described according to the following arrangement: direct knockout reactions (completion of [sup 16]O(e,e[prime]p), [sup 12]C(e,e[prime]pp) progress, large acceptance detector physics simulations), giant resonance studies (intermediate-energy experiments with solid-state detectors, the third response function in [sup 12]C(e,e[prime]p[sub 0]) and [sup 16]O(e,e[prime]p[sub 0]), comparison of the [sup 12]C(e, e[prime]p[sub 0]) and [sup 16]O(e,e[prime]p[sub 3]) reactions, quadrupole strength in the [sup 16]O(e,e[prime][alpha][sub 0]) reaction, quadrupole strength in the [sup 12]C(e,e[prime][alpha]) reaction, analysis of the [sup 12]C(e,e[prime]p[sub 1]) and [sup 16]O(e,e[prime]p[sub 3]) angular distributions, analysis of the [sup 40]Ca(e,e[prime]x) reaction at low q, analysis of the higher-q [sup 12]C(e,e[prime]x) data from Bates), models of nuclear structure (experimental work, Hartree-Fock calculations, phonon excitations in spherical nuclei, shell model calculations, variational methods for relativistic fields), and instrumentation development efforts (developments at CEBAF, CLAS contracts, BLAST developments).

Not Available

1992-01-01

374

Quadrupole-collective states in a large single-j shell  

NASA Astrophysics Data System (ADS)

We discuss the ability of the generator coordinate method (GCM) to select collective states in microscopic calculations. The model studied is a single-j shell with a Hamiltonian containing the quadrupole-quadrupole interaction. Quadrupole-collective excitations are constructed by means of the quadrupole single-particle operator. Lowest collective bands for j=31/2 and particle numbers N=4, 6, 8, 10, 12, and 14 are found. For lower values of j, exact solutions are obtained and compared with the GCM results.

Burzy?ski, K.; Dobaczewski, J.

1995-04-01

375

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

376

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

377

Quadrupole-collective states in a large single-[ital j] shell  

SciTech Connect

We discuss the ability of the generator coordinate method (GCM) to select collective states in microscopic calculations. The model studied is a single-[ital j] shell with a Hamiltonian containing the quadrupole-quadrupole interaction. Quadrupole-collective excitations are constructed by means of the quadrupole single-particle operator. Lowest collective bands for [ital j]=31/2 and particle numbers [ital N]=4, 6, 8, 10, 12, and 14 are found. For lower values of [ital j], exact solutions are obtained and compared with the GCM results.

Burzynski, K. (Institute of Theoretical Physics, Warsaw University, Hoza 69, PL-00-681 Warsaw (Poland)); Dobaczewski, J. (Institute of Theoretical Physics, Warsaw University, Hoza 69, PL-00-681 Warsaw (Poland) University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States))

1995-04-01

378

Evaluate the Options of Implementing Skew Quadrupoles in the High Energy Ring  

SciTech Connect

There are six skew quadrupoles needed in each side of the interaction region to compensate the effects of coupling and vertical dispersion due to the solenoid detector. Two of those skew quadrupoles are at the location of the first pair of the local chromatic sextupoles in the arcs adjacent the interaction region. To avoid introducing high order aberration, the skew quadrupoles could not be placed between the sextupoles pair. In this note, we evaluate two options of implementing the skew quadrupoles at those locations, namely adding trim coil into the sextupoles or vertically displacing the sextupoles.

Cai, Yunhai

1999-03-09

379

Friction in nuclear dynamics  

SciTech Connect

The problem of dissipation in nuclear dynamics is related to the breaking down of nuclear symmetries and the transition from ordered to chaotic nucleonic motions. In the two extreme idealizations of the perfectly Ordered Regime and the fully Chaotic Regime, the nucleus should behave as an elastic solid or an overdamped fluid, respectively. In the intermediate regime a complicated visco-elastic behaviour is expected. The discussion is illustrated by a simple estimate of the frequency of the giant quadrupole resonance in the Ordered Regime and by applications of the wall and window dissipation formulae in the Chaotic Regime. 51 refs.

Swiatecki, W.J.

1985-03-01

380

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

Marcus, R.

1991-01-01

381

Understanding Life  

NSDL National Science Digital Library

Understanding Life is the educational website of The Physiological Society, providing "support for the teaching and learning of physiology." A good place to start is the What is Physiology? area, which offers an overview of this field of human inquiry. The Resources area is a well-designed archive of instructional materials that include "The story of a single heartbeat," "The Science of Life," and "Planning an experiment." It's worth noting that visitors can create their own accounts on the site so they can receive specialized newsletters, tailored website content, and become eligible to enter scientific competitions. Moving along, the Events area lists important goings-on that will be of interest to educators and those involved with science pedagogy. [KMG

382

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!"

Hartman, Monica

2007-12-01

383

The statistical mechanics of ion-dipole-tetrahedral quadrupole mixtures  

NASA Astrophysics Data System (ADS)

We examine the solution of the Ornstein-Zernike equations for the correlation functions of a fluid mixture in which the molecular interactions consist of a hard sphere plus a multipolar potential that contains coulombic, dipolar as well as quadrupolar terms. In particular we consider the case in which the molecule has a dipole moment in the z direction of the molecular axis system and a non-linear tetrahedral quadrupole tensor of the form ?xx = - ?yy, ?zz = 0 = ???, ? ? ? in the molecular frame. This model is a good representation of the dipolar and quadrupolar properties of water and our analysis will form the basis for constructing a Civilized Model electrolyte in which ions are dissolved in a solvent whose molecules possess water-like multipole moments. One of our main results is that for any theory which retains only the subset of rotational invariants that either appear in the interaction potentials or are generated by angular convolution from those appearing in the interaction potentials, e.g. the linearized hypernetted chain (LHNC) or mean spherical approximations (MSA), the equations for an ion-dipole-tetrahedral quadrupolar mixture only differ from those for an ion-dipole-linear quadrupole mixture (?xx = ?yy = - 1/2?zz, ??? = 0, ? ? ?) in minor details. We have investigated the thermodynamic properties of a fluid of hard spheres with the dipole and tetrahedral moments of water using thermodynamic perturbation theory. We find that contributions to the thermodynamic properties from dipole-quadrupole interaction are very important. For a pure hard sphere tetrahedral quadrupolar fluid there is considerable difference between the results from perturbation theory and from the MSA, for which we have obtained an analytic solution.

Carnie, Steven L.; Chan, Derek Y. C.; Walker, Glen R.

384

CMB quadrupole suppression. I. Initial conditions of inflationary perturbations  

SciTech Connect

We investigate the issue of initial conditions of curvature and tensor perturbations at the beginning of slow roll inflation and their effect on the power spectra. Renormalizability and small backreaction constrain the high k behavior of the Bogoliubov coefficients that define these initial conditions. We introduce a transfer function D(k) which encodes the effect of generic initial conditions on the power spectra. The constraint from renormalizability and small backreaction entails that D(k)(less-or-similar sign){mu}{sup 2}/k{sup 2} for large k, implying that observable effects from initial conditions are more prominent in the low multipoles. This behavior affects the CMB quadrupole by the observed amount {approx}10%-20% when {mu} is of the order of the energy scale of inflation. The effects on high l-multipoles are suppressed by a factor {approx}1/l{sup 2} due to the falloff of D(k) for large wave vectors k. We show that the determination of generic initial conditions for the fluctuations is equivalent to the scattering problem by a potential V({eta}) localized just prior to the slow roll stage. Such potential leads to a transfer function D(k) which automatically obeys the renormalizability and small backreaction constraints. We find that an attractive potential V({eta}) yields a suppression of the lower CMB multipoles. Both for curvature and tensor modes, the quadrupole suppression depends only on the energy scale of V({eta}), and on the time interval where V({eta}) is nonzero. A suppression of the quadrupole for curvature perturbations consistent with the data is obtained when the scale of the potential is of the order of k{sub Q}{sup 2} where k{sub Q} is the wave vector whose physical wavelength is the Hubble radius today.

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

385

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

386

Gauge potential for neutral atoms in a magnetic quadrupole field  

NASA Astrophysics Data System (ADS)

We consider a spinor Bose-Einstein condensate of neutral atoms in a magnetic quadrupole field and investigate the gauge potential derived from the spatially-varying magnetic field. We discuss the critical condition for a singular, quantized vortex state being energetically favored in the spinor condensate and find that it is necessary under experimentally realistic conditions to use atoms with hyperfine spin F > 1 and/or a more spatially-varying magnetic field, e.g., hexapole or octopole fields. Finally, we show that a spinor condensate in a ring geometry is beneficial for observing the gauge potential effects.

Shin, Yong-il; Choi, Jae-yoon

2013-08-01

387

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

388

Optically plugged quadrupole trap for Bose-Einstein condensates  

SciTech Connect

We created sodium Bose-Einstein condensates in an optically plugged quadrupole magnetic trap. A focused, 532-nm laser beam repelled atoms from the coil center where Majorana loss is significant. We produced condensates containing up to 3x10{sup 7} atoms, a factor of 60 improvement over previous work and a number comparable to the best all-magnetic traps, and transferred up to 9x10{sup 6} atoms into a purely optical trap. We compare our observations with a simple model of evaporative cooling, concluding that a laser in the range of 1 W (rather than 5 W) may suffice.

Naik, D.S.; Raman, C. [School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States)

2005-03-01

389

Dipole-quadrupole dynamics during magnetic field reversals  

SciTech Connect

The shape and the dynamics of reversals of the magnetic field in a turbulent dynamo experiment are investigated. We report the evolution of the dipolar and the quadrupolar parts of the magnetic field in the VKS experiment, and show that the experimental results are in good agreement with the predictions of a recent model of reversals: when the dipole reverses, part of the magnetic energy is transferred to the quadrupole, reversals begin with a slow decay of the dipole and are followed by a fast recovery, together with an overshoot of the dipole. Random reversals are observed at the borderline between stationary and oscillatory dynamos.

Gissinger, Christophe [Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08544 (United States)

2010-11-15

390

Quadrupole Collectivity Of Neutron-Rich Light Nuclei  

NASA Astrophysics Data System (ADS)

The angular momentum projected Generator Coordinate Method, with the quadrupole moment as collective coordinate and the Gogny force as the effective interaction, is used to describe the properties of the ground state and low-lying excited states of the even-even Magnesium isotopes 20-40Mg. It is found that the ground states of the N=20 32Mg and N=28 40Mg nuclei are deformed and therefore the corresponding shell closures are not preserved. Rather good agreement with experimental data for many observables is obtained.

Rodríguez-Guzmán, R. R.; Egido, J. L.; Robledo, L. M.

2003-03-01

391

Manifestation of quadrupole collectivity in the magnetic dipole strength  

NASA Astrophysics Data System (ADS)

We discuss the systematics of E2 and M1 transition strengths as obtained from experimental data in the rare-earth region. The similarity is studied in the light of the observed dependence of E2 and M1 transition strength on quadrupole deformation. Especially the ``saturation'' effect for these electromagnetic observables is discussed, starting from the Nilsson deformed-shell model. The data are compared to the present calculations, using a QTDA approach. The particular E2-M1 correlation is investigated within the IBM-2 using a sum-rule approach.

Heyde, K.; de Coster, C.; Richter, A.; Wörtche, H.-J.

1992-11-01

392

Finding the Magnetic Center of a Quadrupole to High Resolution  

SciTech Connect

In a companion pro, collposal it is proposed to align quadrupoles of a transport line to within transverse tolerances of 5 to 10 micrometers. Such a proposal is meaningful only if the effective magnetic center of such lenses can in fact be repeatably located with respect to some external mechanical tooling to comparable accuracy. It is the purpose of this note to describe some new methods and procedures that will accomplish this aim. It will be shown that these methods are capable of yielding greater sensitivity than the more traditional methods used in the past. The notion of the ''nodal'' point is exploited.

Fischer, G.E.; Cobb, J.K.; Jenson, D.R.; /SLAC

2005-08-12

393

Orbital currents, anapoles, and magnetic quadrupoles in CuO  

SciTech Connect

We show that orbital currents in a CuO{sub 2} plane, if present, should be described by two independent parity- and time-reversal-odd order parameters, a toroidal dipole (anapole) and a magnetic quadrupole. Based on this, we derive the resonant x-ray diffraction cross section for monoclinic CuO at the antiferromagnetic wave vector and show that the two order parameters can be disentangled. From our analysis, we examine a recent claim of detecting anapoles in CuO.

Di Matteo, S.; Norman, M. R. (Materials Science Division); (Universite de Rennes)

2012-01-01

394

2-MV electrostatic quadrupole injector for heavy-ion fusion  

NASA Astrophysics Data System (ADS)

High current and low emittance are principal requirements for heavy-ion injection into a linac driver for inertial fusion energy. An electrostatic quadrupole injector is capable of providing these high charge density and low emittance beams. We have modified the existing 2-MV injector to reduce beam emittance and to double the pulse length. We characterize the beam delivered by the modified injector to the High Current Transport Experiment and the effects of finite rise time of the extraction voltage pulse in the diode on the beam head. We demonstrate techniques for mitigating aberrations and reducing beam emittance growth in the injector.

Bieniosek, F. M.; Celata, C. M.; Henestroza, E.; Kwan, J. W.; Prost, L.; Seidl, P. A.; Friedman, A.; Grote, D. P.; Lund, S. M.; Haber, I.

2005-01-01

395

2-MV electrostatic quadrupole injector for heavy-ion fusion  

SciTech Connect

High current and low emittance are principal requirements for heavy-ion injection into a linac driver for inertial fusion energy. An electrostatic quadrupole (ESQ) injector is capable of providing these high charge density and low emittance beams. We have modified the existing 2-MV Injector to reduce beam emittance and to double the pulse length. We characterize the beam delivered by the modified injector to the High Current Transport Experiment (HCX) and the effects of finite rise time of the extraction voltage pulse in the diode on the beam head. We demonstrate techniques for mitigating aberrations and reducing beam emittance growth in the injector.

Bieniosek, F.M.; Celata, C.M.; Henestroza, E.; Kwan, J.W.; Prost, L.; Seidl, P.A.

2004-11-10

396

Tests of high gradient superconducting quadrupole magnets for the Tevatron  

SciTech Connect

Tests have been completed on three prototype magnets and two production magnets to be used for the Tevatron D{phi}/B{phi} low- {beta} insertion. These cold iron, two shell quadrupoles are made of 36 strand Rutherford type NbTi superconducting cable. Magnet field gradients well in excess of the design 1.41 T/cm have been achieved at a transfer function of 0.291 T/cm/kA. Quench performance at 4.2 K and 3.7 K and magnetic multipole measurement data are presented and discussed. 9 refs., 4 figs., 4 tabs.

Lamm, M.J.; Carson, J.; Gourlay, S.; Hanft, R.; Koepke, K.; Mantsch, P.; McInturff, A.D.; Riddiford, A.; Strait, J.

1989-09-01

397

Superconducting focusing quadrupoles for heavy ion fusion experiments  

SciTech Connect

The Heavy Ion Fusion (HIF) Program is developing superconducting focusing magnets for both near-term experiments and future driver accelerators. In particular, single bore quadrupoles have been fabricated and tested for use in the High Current Experiment (HCX) at Lawrence Berkeley National Laboratory (LBNL). The next steps involve the development of magnets for the planned Integrated Beam Experiment (IBX) and the fabrication of the first prototype multi-beam focusing arrays for fusion driver accelerators. The status of the magnet R&D program is reported, including experimental requirements, design issues and test results.

Sabbi, G.L.; Faltens, A.; Leitner, M.; Lietzke, A.; Seidl, P.; Barnard, J.; Lund, S.; Martovetsky, N.; Gung, C.; Minervini, J.; Radovinsky, A.; Schultz, J.; Meinke, R.

2003-05-01

398

Deuteron Quadrupole Coupling Constant in CH3D  

Microsoft Academic Search

The deuteron electric-field gradient qD and quadrupole coupling constant (eqQ\\/h)D for CH3D have been calculated from extended basis-set LCAO-MO-SCF wavefunctions determined by Woznick for this system. Comparison of the results for different wavefunctions and different distances suggest that a reasonable theoretical estimate is (eqQ\\/h)D=210±30 kc\\/sec. Since this disagrees significantly with the present experimental estimate [(eqQ\\/h)D=100±50 kc\\/sec], a more refined measurement

T. Caves; M. Karplus

1966-01-01

399

Test of eight superconducting arc quadrupoles for RHIC  

SciTech Connect

Test results from a group of eight superconducting quadrupoles at Brookhaven National Laboratory are presented. The magnets have been designed for use in the arc regions of the Relativistic Heavy Ion Collider now under construction at Brookhaven. Novel features of the design include a single-layer coil, the use of injection-molded phenolic for the pole spacers, and a yoke that also serves as a collar. This R&D series has been used to verify the magnet quench performance and field quality prior to the start of the production run in industry.

Wanderer, P.; Anerella, M.; Ganetis, G. [and others

1993-12-31

400

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

401

Radio-frequency quadrupole: general properties and specific applications  

SciTech Connect

The radio-frequency quadrupole (RFQ) linac structure is being developed for the acceleration of low-velocity ions. Recent experimental tests have confirmed its expected performance and have led to an increased interest in a wide range of possible applications. The general properties of RFQ accelerators are reviewed and beam dynamics simulation results are presented for their use in a variety of accelerating systems. These include the low-beta sections of the Fusion Materials Irradiation Test Accelerator, a 200-MHz proton linear accelerator, and a xenon accelerator for heavy ion fusion.

Stokes, R.H.; Crandall, K.R.; Hamm, R.W.

1980-01-01

402

Magnetic quadrupole doublet focusing system for high energy ions  

SciTech Connect

A high energy focused ion beam microprobe using a doublet arrangement of short magnetic quadrupole lenses was used to focus 1-3 MeV protons to spot sizes of 1x1 {mu}m{sup 2} and 1-4.5 MeV carbon and silicon ion beams to spot sizes of 1.5x1.5 {mu}m{sup 2}. The results presented clearly demonstrate that this simple doublet configuration can provide high energy microbeams for microananalysis and microfabrication applications.

Glass, Gary A.; Dymnikov, Alexander D.; Dias, Johnny F.; Houston, Louis M.; LeBlanc, Jared [Louisiana Accelerator Center/Physics Department, The University of Louisiana at Lafayette, P.O. Box 44210, Lafayette, Louisiana 70504-4210 (United States); Rout, Bibhudutta [Department of Physics, University of North Texas, P.O. Box 311427, Denton, Texas 76203 (United States)

2008-03-15

403

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

404

Comparison of liquid chromatography using triple quadrupole and quadrupole ion trap mass analyzers to determine pesticide residues in oranges.  

PubMed

Liquid chromatography-triple quadrupole/mass spectrometry (LC-TQ/MS) and liquid chromatography-quadrupole ion trap/mass spectrometry (LC-QIT/MS) for determining bupirimate, hexaflumuron, tebufenpyrad, buprofezin, pyriproxyfen, and fluvalinate in fruits have been compared. The differences in the mass spectra obtained by triple and ion trap quadrupoles are discussed, showing how both of them provide interesting features. The evaluation of the two instruments was carried out by ethyl acetate extraction of oranges spiked with the studied pesticides at LOQ and 10 times the LOQ. Results obtained by LC-TQ/MS correlated well with those obtained by LC-QIT/MS. Recoveries were 70-94% by LC-TQ/MS and 72-92% by LC-QIT/MS with the R.S.D. from five replicate analysis 4-14% and 8-18%, respectively. Matrix effects were tested for both techniques by standard addition to blank extracts. Although the matrix effects are not originated in mass analyzer but in the LC/MS interface, they were, generally, more marked by LC-QIT-MS than by LC-TQ/MS. The limits of quantification (LOQs) were 0.005-0.2 mg kg(-1) by both equipments--appropriate values for determining these pesticides in orange from the regulatory point of view. The results indicate that the TQ provides higher precision, better linearity, it is more robust, and when the purpose of the analysis is quantitative determination, preferable over the QIT. However, the application of both mass spectrometers to analyze orange samples conventionally treated showed that any can be used for qualitative and quantitative purposes. PMID:15844516

Soler, Carla; Mañes, Jordi; Picó, Yolanda

2005-03-01

405

Radiation-hardened field coils for FMIT quadrupoles  

SciTech Connect

Modern accelerators of the Fusion Materials Irradiation Test (FMIT) class deliver enormous power onto their targets. The high beam currents of such machines produce highly activating radiation fields from beam/target interaction and normal beam losses. The 100-mA deuteron beam from the FMIT accelerator produces a backstreaming fast-neutron flux of 10/sup 11/ n/s-cm/sup 2/ near the target. In addition, the neutron contribution from distributed beam spill of 3 ..mu..A/m along the rest of the machine prevents the use of epoxy resin potting materials in all magnet field coils above 10-MeV beam energies. Two special techniques for radiation-hardened field coils have been developed at Los Alamos for use on the FMIT accelerator. One technique uses vitreous enamel coatings on the conductors and appears attractive for the drift-tube quadrupoles. Another method uses a thermally efficient two-layer coil design that has solid mineral-insulated (MI) conductors with indirect cooling coils, all bonded together in a lead matrix. Test results are discussed, along with applications of the quadrupoles in the FMIT facility that reduce gamma exposures during maintenance periods.

Grieggs, R.J.; Liska, D.J.; Harvey, A.

1983-01-01

406

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

407

A superconducting iron-dominated quadrupole for CEBAF  

SciTech Connect

The present design for the high-resolution spectrometers at CEBAF requires a front quadrupole (QO) that has a gradient x length of 6.8 T with a good field aperture (1x10/sup -8/ uniformity in gradient) of 16 cm radius. A room temperature design was found too power hungry and interfered with the beam. Engineering and construction of a small cos 2theta magnet was considered to be quite expensive. A Panofsky design was not considered due to the extreme sensitivity of the field quality to errors in conductor placement. A conformal mapping of a window-frame dipole into quadrupole geometry worked well at NSCL. A conceptual design has been developed with the following characteristics; physical length (total)= 1.2 m; iron length= 1.1 m; iron outer dimensions= 54 cm x 80 cm; peak gradient= 6.2 T/m; pole radius= 20 cm; Good field radius= 16 cm; coil peak field= 1.5 T; conductor= 1 mm diameter; Cu/NbTi= 7:1; current= 400 A; turns= 250/quadrant; stored energy= 50 kJ.

Harwood, L.H.; Lassiter, S.; Tuzel, W.

1989-03-01

408

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

409

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

410

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

411

The quadrupole model for rigid-body gravity simulations  

NASA Astrophysics Data System (ADS)

We introduce two new models for gravitational simulations of systems of non-spherical bodies, such as comets and asteroids. In both models, one body (the "primary") may be represented by any convenient means, to arbitrary accuracy. In our first model, all of the other bodies are represented by small gravitational "molecules" consisting of a few point masses, rigidly linked together. In our second model, all of the other bodies are treated as point quadrupoles, with gravitational potentials including spherical harmonic terms up to the third degree (rather than only the first degree, as for ideal spheres or point masses). This quadrupole formulation may be regarded as a generalization of MacCullagh's approximation. Both models permit the efficient calculation of the interaction energy, the force, and the torque acting on a small body in an arbitrary external gravitational potential. We test both models for the cases of a triaxial ellipsoid, a rectangular parallelepiped, and "duplex" combinations of two spheres, all in a point-mass potential. These examples were chosen in order to compare the accuracy of our technique with known analytical results, but the ellipsoid and duplex are also useful models for comets and asteroids. We find that both approaches show significant promise for more efficient gravitational simulations of binary asteroids, for example. An appendix also describes the duplex model in detail.

Dobrovolskis, Anthony R.; Korycansky, D. G.

2013-07-01

412

Liquid chromatography with triple-quadrupole or quadrupole-time of flight mass spectrometry for screening and confirmation of residues of pharmaceuticals in water  

Microsoft Academic Search

LC–MS–MS has been performed with triple-quadrupole (QqQ) and quadrupole-time of flight (Q-ToF) instruments and has been used for screening and confirmation of pharmaceuticals in surface, drinking, and ground water. Screening was based on monitoring of one specific MS–MS ion of the target compounds. Confirmation of the identity of the pharmaceuticals was based either on the monitoring of two specific MS–MS

Alida A. M. Stolker; Willem Niesing; Elbert A. Hogendoorn; Johanna F. M. Versteegh; Regine Fuchs; Udo A. Th. Brinkman

2004-01-01

413

Simulation of Kinematic of an Electron Motion in Quadrupole Microwave Amplifier on Adler Device  

Microsoft Academic Search

The possibility of computer simulation of a potential distribution in quadrupole section of Adler device are considered. The kinematic of driving and configuration of a beam coupling before passing by it of a quadrupole zone of a microwave amplifier is shown

A. A. Yelizarov; Ye. A. Sorokin

2006-01-01

414

Measurement of the aberrations of an electrostatic quadrupole probe forming lens system  

Microsoft Academic Search

A Russian antisymmetric quadruplet of precision electrostatic quadrupole lenses is used to focus a MeV proton probe for ion beam analysis of geological specimens. The aberrations of the individual lenses have been measured with the grid shadow method and the lenses have been found to be remarkably free from parasitic sextupole contamination, commonly seen in magnetic quadrupole lenses. The most

D. N. Jamieson; C. G. Ryan; S. H. Sie

1991-01-01

415

Single quadrupole mass spectrometry for pre-clinical pharmacokinetic analysis: Quantitation of carvedilol in dog plasma  

Microsoft Academic Search

The pharmaceutical industry standard for bioanalysis is LC\\/MS\\/MS. There are, however, many instances where a single quadrupole detector could successfully be used to provide adequate sensitivity and selectivity for quantitation of drug substances in biological matrices. This paper presents one example of how a single quadrupole detector can be employed in a sensitive and selective analytical method for quantitation of

M. P. McIntosh; B. J. Carlson; K. S. Schorno; R. A. Rajewski

2007-01-01

416

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

Microsoft Academic Search

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 provides a method of achieving this size reduction. A quadrupole mass filter (QMF) is one component of a QMS and is suitable for microfabrication. MEMS manufacturing techniques are more suitable to the production

Thomas J. Hogan; Stephen Taylor; Kerry Cheung; Luis Fernando Velasquez-Garcia; Akintunde Ibitayo Akinwande; Randall E. Pedder

2010-01-01

417

Measuring the Magnetic Center Behavior of an ILC Superconducting Quadrupole Prototype  

SciTech Connect

The main linacs of the proposed International Linear Collider (ILC) consist of superconducting cavities operated at 2K. The accelerating cavities are contained in a contiguous series of cryogenic modules that also house the main linac quadrupoles, thus the quadrupoles also need to be superconducting. In an early ILC design, these magnets are about 0.6 m long, have cos (2{theta}) coils, and operate at constant field gradients up to 60 T/m. In order to preserve the small beam emittances in the ILC linacs, the e+ and e- beams need to traverse the quadrupoles near their magnetic centers. A quadrupole shunting technique is used to measure the quadrupole alignment with the beams; this process requires the magnetic centers move by no more than about 5 micrometers when their strength is changed. To determine if such tight stability is achievable in a superconducting quadrupole, we at SLAC measured the magnetic center motions in a prototype ILC quadrupole built at CIEMAT in Spain. A rotating coil technique was used with a better than 0.1 micrometer precision in the relative field center position, and less than a 2 micrometer systematic error over 30 minutes. This paper describes the warm-bore cryomodule that houses the quadrupole in its Helium vessel, the magnetic center measurement system, the measured center data and strength and harmonics magnetic data.

Spencer, Cherrill M.; Adolphsen, Chris; Berndt, Martin; Jensen, David R.; Rogers, Ron; Sheppard, John C.; Lorant, Steve St; Weber, Thomas B.; Weisend, John, II; /SLAC; Brueck, Heinrich; /DESY; Toral, Fernando; /Madrid, CIEMAT

2011-02-07

418

A combined ¹H nuclear magnetic resonance and electrospray ionization-mass spectrometry analysis to understand the basal metabolism of plant-pathogenic Fusarium spp.  

PubMed

Many ascomycete Fusarium spp. are plant pathogens that cause disease on both cereal and noncereal hosts. Infection of wheat ears by Fusarium graminearum and F. culmorum typically results in bleaching and a subsequent reduction in grain yield. Also, a large proportion of the harvested grain can be spoiled when the colonizing Fusarium mycelia produce trichothecene mycotoxins, such as deoxynivalenol (DON). In this study, we have explored the intracellular polar metabolome of Fusarium spp. in both toxin-producing and nonproducing conditions in vitro. Four Fusarium spp., including nine well-characterized wild-type field isolates now used routinely in laboratory experimentation, were explored. A metabolic "triple-fingerprint" was recorded using (1)H nuclear magnetic resonance and direct-injection electrospray ionization-mass spectroscopy in both positive- and negative-ionization modes. These combined metabolomic analyses revealed that this technique is sufficient to resolve different wild-type isolates and different growth conditions. Principal components analysis was able to resolve the four species explored-F. graminearum, F. culmorum, F. pseudograminearum, and F. venenatum-as well as individual isolate differences from the same species. The external nutritional environment was found to have a far greater influence on the metabolome than the genotype of the organism. Conserved responses to DON-inducing medium were evident and included increased abundance of key compatible solutes, such as glycerol and mannitol. In addition, the concentration of ?-aminobutyric acid was elevated, indicating that the cellular nitrogen status may be affected by growth on DON-inducing medium. PMID:20718668

Lowe, Rohan G T; Allwood, J William; Galster, Aimee M; Urban, Martin; Daudi, Arsalan; Canning, Gail; Ward, Jane L; Beale, Michael H; Hammond-Kosack, Kim E

2010-12-01

419

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

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

Combination of magnetic and electric quadrupole lenses as zoom Sextuplet ion microprobe focusing system with minimum spherical aberration  

NASA Astrophysics Data System (ADS)

The new generation nuclear microprobe system at the Louisiana Accelerator Center in the University of Louisiana at Lafayette consists of a 6.25 m beam line that employs the magnetic quadrupole Sextuplet lens system. This Sextuplet is a zoom system having the same demagnifications, the same focal lengths and the same positions of the focal points in (xoz) and (yoz) planes as in the case for the Russian quadruplet. It also can have the same spherical aberrations in both planes. The parameters which allow obtaining the lowest coefficients of spherical aberration are found for different geometrical configurations of electric and magnetic quadrupole lenses. Specifically, the configuration of a combined Sextuplet consisting of two magnetic and four electrostatic lenses or consisting of two electrostatic and four magnetic lenses is studied and compared with magnetic and electrostatic Sextuplets. The values of the chromatic and spherical aberrations for these combined systems are compared and the minimum spot radius and the half-widths of the corresponding slits for some optimal magnetic and electrostatic Sextuplets are given.

Dymnikov, Alexander D.; Rout, Bibhudutta; Glass, Gary A.

2007-08-01

422

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

423

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

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

Nuclear chemistry research and spectroscopy with radioactive sources. Twentieth annual progress report, September 1, 1983-August 31, 1984  

SciTech Connect

Research under this continuing DOE contract centers on radioactive decay studies of nuclei far from stability produced with heavy ions from the Holifield Heavy Ion Research Facility (HHIRF) and studied on-line with the University Isotope Separator at Oak Ridge (UNISOR). These investigations encompass three aspects of nuclear structure research: nuclear spectroscopic measurements involving detailed ..gamma gamma..t, ..gamma..e/sup -/t, and X..gamma..t three-parameter coincidence spectrometry; on-line laser hyperfine structure (hfs) and isotope shift spectroscopy for determining quadrupole moments, nuclear spins, and mean nuclear charge radii; and computer calculations of nuclear model predictions for comparison with the experimental level schemes. The focus of this research program is on odd-mass nuclei in which the odd nucleon probes the core, making possible observation of such phenomena as the onset of abrupt shape changes, the occurrence of shape coexistence, and shell-model intruder states. These phenomena are critical tests of concepts fundamental to an understanding of low-energy nuclear structure, such as nuclear deformations, shell models, collective models, and particle-core couplings.

Fink, R.W.

1984-08-31

426

Time-dependent quadrupole interactions in 129I  

NASA Astrophysics Data System (ADS)

?-? time-differential directional correlation studies have been carried out on the 52+ (459.6 keV) 52+ (27.8 keV) 72+ cascade in 129I using a 129Tem+g source in 4N HCl. The measurements reveal time-dependent electric quadrupole perturbation of the correlation. From the plot of A2(t¯) vs t¯ (finite time resolution corrected), the obtained values of the relaxation parameter ?el2 and the unperturbed A2(0) coefficient (solid angle corrected) are (0.21+/-0.01) × 109 sec-1 and -(0.068+/-0.002), respectively. The observed ?el2 is consistent with that deduced from the theory of Abragam and Pound. RADIOACTIVITY 129Tem+g [from 128Te(n,?)] measured ?-?(?,t) deduced ?el2,A2(0),G¯2(?).

Gupta, S. L.; Kumar, Ashok; Soni, S. K.; Pancholi, S. C.

1980-06-01

427

The Dynamic Aperture of an Electrostatic Quadrupole Lattice  

SciTech Connect

In heavy-ion-driven inertial fusion accelerator concepts, dynamic aperture is important to the cost of the accelerator, most especially for designs which envision multibeam linacs, where extra clearance for each beam greatly enlarges the transverse scale of the machine. In many designs the low-energy end of such an accelerator uses electrostatic quadrupole focusing. The dynamic aperture of such a lattice has been investigated here for intense, space-charge-dominated ion beams using the 2-D transverse slice version of the 3-D particle-in-cell simulation code WARP. The representation of the focusing field used is a 3-D solution of the Laplace equation for the biased focusing elements, as opposed to previous calculations, which used a less-accurate multipole approximation. 80-85% radial filling of the aperture is found to be possible. Results from the simulations, as well as corroborating data from the High Current Experiment at LBNL, are presented.

Celata, C.M.; Bieniosek, F.M.; Prost, L.; Seidl, P.A.; Friedman,A.; Grote, D.P.

2005-05-01

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

A radio frequency quadrupole ion beam buncher for ISOLTRAP  

SciTech Connect

ISOLTRAP is a Penning trap spectrometer at the on-line mass separator ISOLDE at CERN for the mass determination of radioisotopes. It consists of three electromagnetic traps in tandem; a Paul trap for ISOLDE beam collection, a Penning trap for cooling and purification and a high-precision Penning trap for the measurement of masses by cyclotron resonance. The Paul trap, which collects radionuclide ions using only electric fields and a noble buffer gas, has been essential for the masses of radionuclides that cannot be surface ionized. The success with this system has led to the present program to increase the collection efficiency by replacing the Paul trap by a radiofrequency quadrupole ion guide operating as a buncher. This system would also provide a DC ISOLDE beam of emittance approaching 1 {pi}-mm-mrad.

Bollen, G. [CERN, CH-1211 Geneva 23 (Switzerland); Dilling, J.; Herfurth, F.; Kluge, H.-J.; Kohl, A.; Lamour, E.; Quint, W.; Schwarz, S.; Vermeeren, L. [GSI, Planckstr. 1, D-64291 Darmstadt (Germany); Dezfuli, A. M. Ghalambor; Kellerbauer, A.; Kim, T.; Moore, R. B.; Varfalvy, P. [McGill University, 3600 University St., Montreal, QC, H3A 2T8 (Canada); Henry, S.; Lunney, D. [CSNSM-IN2P3-CNRS, F-91405 Orsay-Campus (France)

1998-12-21

430

Restoring the skew quadrupole moment in the Tevatron dipoles  

SciTech Connect

In early 2003 it was realized that mechanical changes in the Tevatron dipoles had led to a deterioration of the magnetic field quality that was hindering operation of the accelerator. After extensive study, a remediation program was started in late 2003 that will continue through 2005. The mechanical and magnetic effects are discussed. The readjustment process and experience are reported, along with other observations on aging magnets. In January 2003 two lines of inquiry converged, leading to the recognition that the severe betatron coupling that was hindering operation of the Tevatron could be explained by a systematic shift on the skew quadrupole field in the dipole magnets of the same size expected from observed mechanical movement of the coils inside the magnet yokes [1]. This paper reports on subsequent magnet studies that were conducted in parallel with additional beam studies and accelerator modeling [2] exploring the feasibility of the eventual remediation effort [3].

Harding, D.J.; Bauer, P.C.; Blowers, J.N.; DiMarco, J.; Glass, H.D.; Hanft, R.W.; Carson, J.A.; Robotham, W.F.; Tartaglia, M.A.; Tompkins, J.C.; Velev, G.; /Fermilab

2005-05-01

431

Quadrupole Collectivity in Neutron-Rich Fe and Cr Isotopes  

NASA Astrophysics Data System (ADS)

Intermediate-energy Coulomb excitation measurements are performed on the N?40 neutron-rich nuclei Fe66,68 and Cr64. The reduced transition matrix elements providing a direct measure of the quadrupole collectivity B(E2;21+?01+) are determined for the first time in Fe4268 and Cr4064 and confirm a previous recoil distance method lifetime measurement in Fe4066. The results are compared to state-of-the-art large-scale shell-model calculations within the full fpgd neutron orbital model space using the Lenzi-Nowacki-Poves-Sieja effective interaction and confirm the results of the calculations that show these nuclei are well deformed.

Crawford, H. L.; Clark, R. M.; Fallon, P.; Macchiavelli, A. O.; Baugher, T.; Bazin, D.; Beausang, C. W.; Berryman, J. S.; Bleuel, D. L.; Campbell, C. M.; Cromaz, M.; de Angelis, G.; Gade, A.; Hughes, R. O.; Lee, I. Y.; Lenzi, S. M.; Nowacki, F.; Paschalis, S.; Petri, M.; Poves, A.; Ratkiewicz, A.; Ross, T. J.; Sahin, E.; Weisshaar, D.; Wimmer, K.; Winkler, R.

2013-06-01

432

Design and fabrication of the BNL radio frequency quadrupole  

SciTech Connect

The Brookhaven National Laboratory polarized H/sup -/ injection program for the AGS will utilize a Radio Frequency Quadrupole for acceleration between the polarized source and the Alvarez Linac. Although operation will commence with a few ..mu.. amperes of H/sup -/ current, it is anticipated that future polarized H/sup -/ sources will have a considerably improved output. The RFQ will operate at 201.25 MHz and will be capable of handling a beam current of 0.02 amperes with a duty cycle of 0.25%. The resulting low average power has allowed novel solutions to the problems of vane alignment, rf current contacts, and removal of heat from the vanes. The cavity design philosophy will be discussed together with the thermodynamics of heat removal from the vane. Details of the fabrication will be presented with a status report.

McKenzie-Wilson, R.B.

1983-01-01

433

Thermal noise in aqueous quadrupole micro- and nano-traps  

PubMed Central

Recent simulations and experiments with aqueous quadrupole micro-traps have confirmed a possibility for control and localization of motion of a charged particle in a water environment, also predicting a possibility of further reduction of the trap size to tens of nano-meters for trapping charged bio-molecules and DNA segments. We study the random thermal noise due to Brownian motion in water which significantly influences the trapping of particles in an aqueous environment. We derive the exact, closed-form expressions for the thermal fluctuations of position and velocity of a trapped particle and thoroughly examine the properties of the rms for the fluctuations as functions of the system parameters and time. The instantaneous signal transferring mechanism between the velocity and position fluctuations could not be achieved in the previous phase-average approaches.

2012-01-01

434

Application of artificial intelligence to triple quadrupole mass spectrometry (TQMS)  

SciTech Connect

At Lawrence Livermore National Laboratory the authors have designed a totally computerized triple quadrupole mass spectrometer with the ultimate goal of using it as a prototype for ''knowledge-based'' instrument control. As an ''intelligent'' instrument, with its computer-based data acquisition and control system, it has the ability to learn and respond quickly. The intelligence is encoded in the system using the representation and rule-based reasoning heuristic techniques of Artificial Intelligence. These techniques are used to encode heuristic knowledge, or the intuition, formal and informal rules, and experiential knowledge that the human expert normally uses to make decisions and arrive at solutions in a specific domain problem. In this specific case, the knowledge the authors are encoding is a tuning procedure for the spectrometer, including heuristics to describe a self-adaptive, feedback control process for real-time optimization or tuning of the data acquisition procedure throughout the entire data collection process.

Wong, C.M.; Crawford, R.W.; Kehler, T.P.; Kunz, J.C.

1984-02-01

435

Degradation studies of Fermilab low beta quadrupole cable  

SciTech Connect

The production of high gradient superconducting quadrupoles for the Tevatron D0/B0 Low Beta insertion is currently underway at Fermilab. The two-shell design utilizes a 36-strand Rutherford style cable produced by Lawrence Berkeley Laboratory. A measure of cable quality is usually given by a comparison of the critical current of the cable with the sum of the critical currents of the strand. A recent study involving variations in the cabling conditions and dimensional parameters has resulted in a significant decrease in degradation. Over the period of cable production degradation has been reduced from an average of 12% to less than 4%. Some cable samples measured by Brookhaven National Laboratory exhibit Jc's in excess of 3100 A/mm{sup 2} 5T. The adjustments to the cabling procedure which are believed to be responsible for the reduction in Jc degradation will be discussed. 14 refs., 3 figs.

Gourlay, S.A. (Fermi National Accelerator Lab., Batavia, IL (USA)); Garber, M. (Brookhaven National Lab., Upton, NY (USA)); Royet, J.; Scanlon, R.M. (Lawrence Berkeley Lab., CA (USA))

1990-10-01

436

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

437

Quasiclassical description of bremsstrahlung accompanying {alpha} decay including quadrupole radiation  

SciTech Connect

We present a quasiclassical theory of {alpha} decay accompanied by bremsstrahlung with a special emphasis on the case of {sup 210}Po, with the aim of finding a unified description that incorporates both the radiation during the tunneling through the Coulomb wall and the finite energy E{sub {gamma}} of the radiated photon up to E{sub {gamma}}{approx}Q{sub {alpha}}/{radical}({eta}), where Q{sub {alpha}} is the {alpha}-decay Q-value and {eta} is the Sommerfeld parameter. The corrections with respect to previous quasiclassical investigations are found to be substantial, and excellent agreement with a full quantum mechanical treatment is achieved. Furthermore, we find that a dipole-quadrupole interference significantly changes the {alpha}-{gamma} angular correlation. We obtain good agreement between our theoretical predictions and experimental results.

Jentschura, U. D. [Max-Planck-Institut fuer Kernphysik, Postfach 103980, D-69029 Heidelberg (Germany); Institut fuer Theoretische Physik, Philosophenweg 16, D-69120 Heidelberg (Germany); Milstein, A. I.; Terekhov, I. S. [Max-Planck-Institut fuer Kernphysik, Postfach 103980, D-69029 Heidelberg (Germany); Budker Institute of Nuclear Physics, RU-630090 Novosibirsk (Russian Federation); Boie, H.; Scheit, H.; Schwalm, D. [Max-Planck-Institut fuer Kernphysik, Postfach 103980, D-69029 Heidelberg (Germany)

2008-01-15

438

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

439

[Electromagnetic studies of nuclear structure and reactions]. Progress summary  

SciTech Connect

The experimental goals are focused on developing an understanding of strong interactions and the structure of hadronic systems by determination of the electromagnetic response; these goals will be accomplished through coincidence detection of final states. Nuclear modeling objectives are to organize and interpret the data through a consistent description of a broad spectrum of reaction observables; calculations are performed in a nonrelativistic diagrammatic framework as well as a relativistic QHD approach. Work is described according to the following arrangement: direct knockout reactions (completion of {sup 16}O(e,e{prime}p), {sup 12}C(e,e{prime}pp) progress, large acceptance detector physics simulations), giant resonance studies (intermediate-energy experiments with solid-state detectors, the third response function in {sup 12}C(e,e{prime}p{sub 0}) and {sup 16}O(e,e{prime}p{sub 0}), comparison of the {sup 12}C(e, e{prime}p{sub 0}) and {sup 16}O(e,e{prime}p{sub 3}) reactions, quadrupole strength in the {sup 16}O(e,e{prime}{alpha}{sub 0}) reaction, quadrupole strength in the {sup 12}C(e,e{prime}{alpha}) reaction, analysis of the {sup 12}C(e,e{prime}p{sub 1}) and {sup 16}O(e,e{prime}p{sub 3}) angular distributions, analysis of the {sup 40}Ca(e,e{prime}x) reaction at low q, analysis of the higher-q {sup 12}C(e,e{prime}x) data from Bates), models of nuclear structure (experimental work, Hartree-Fock calculations, phonon excitations in spherical nuclei, shell model calculations, variational methods for relativistic fields), and instrumentation development efforts (developments at CEBAF, CLAS contracts, BLAST developments).

Not Available

1992-12-31

440

The effects of molecular shape and quadrupole moment on tilted smectic phase formation  

NASA Astrophysics Data System (ADS)

Results are presented from constant NPT Monte Carlo simulations of two systems based on the biaxial internally rotated Gay-Berne (IRGB) potential. First, the effect of increasing molecular elongation is considered, and it is shown that a change in aspect ratio from 3:1 to 4:1 leads to nematic and tilted smectic J phases being replaced by smectic A and tilted smectic G phases, respectively. Second, the effect of a longitudinal electric quadrupole on the phase behaviour of the IRGB model is examined. The presence of a moderate quadrupole moment results in the smectic G phase being replaced by a smectic J; the onset pressure of the smectic J increases monotonically as the quadrupole moment is increased, although the integrity of the tilted layers improves. In addition, the region of smectic A stability is found to persist for moderate quadrupole moment values. For the largest quadrupole moment considered, domains comprising poorly defined, tilted layers are formed but fail to develop into coherent smectic structures. This observation is ascribed to the competition between the unique tilt direction favoured by the biaxial IRGB potential and the random tilt direction of the uniaxial quadrupole-quadrupole interactions.

Withers, Ian M.; Care, Christopher M.; Neal, Maureen P.; Cleaver, Douglas J.

441

Nuclear-spin noise and spontaneous emission  

Microsoft Academic Search

The spontaneous emission from nuclear spins has been observed at liquid-4He temperatures. The spins, 35Cl nuclei, are placed in the inductor of a tuned LCR circuit coupled to a dc superconducting quantum interference device used as a radio-frequency amplifier. When the spins are saturated and have zero polarization, the emission is observed at the nuclear quadrupole Larmor frequency as a

Tycho Sleator; Claude Hilbert; John Clarke

1987-01-01

442

Electrospray Ionization Multiple Stage Quadrupole Ion-Trap and Tandem Quadrupole Mass Spectrometric Studies on Phosphatidylglycerol from Arabidopsis leaves  

PubMed Central

Phosphatidylglycerol (PG) is the major phospholipid of plant chloroplasts. PG from Arabidopsis thaliana has an unusual fatty acyl chain, 3-trans-hexadecenoyl (?316:1) in the sn-2 position of the major 18:3/?316:1-PG species, as well as in 18:2/?316:1-PG and 16:0/?316:1-PG. Upon low-energy collisionally activated dissociation (CAD) in a tandem quadrupole or in an ion-trap mass spectrometer, the [M – H]? ions of the PG molecules containing ?316:1 give product-ion spectra that are readily distinguishable from those arising from PGs without the ?316:1 species. The ?316:1-fatty acyl-containing PGs are characterized by MS2 product-ion mass spectra that contain predominant [M – H – 236]? ions arising from loss of the ?316:1-fatty acyl substituent as a ketene. This is attributable to the fact that the ?-hydrogen of the ?316:1-fatty acid substituent involved in the ketene loss is an allylic hydrogen, which is very labile. This leads to preferential neutral loss of 236 and drastic decline in the neutral loss of 254 (i.e., loss as a fatty acid), the unique features that signify the presence of ?316:1-fatty acyl containing PGs. The neutral loss scan of 236, thus provides a sensitive tandem quadrupole mass spectrometric means to identify ?316:1-containing PG species in lipid mixtures. This low-energy tandem mass spectrometric approach also permits the structures of the Arabidopsis PGs that consist of two isomeric structures to be unveiled.

Hsu, Fong-Fu; Turk, John; Williams, Todd D.; Welti, Ruth

2009-01-01

443

Single crystal 55Mn ENDOR of concanavalin a: detection of two Mn2+ sites with different 55Mn quadrupole tensors.  

PubMed

Concanavalin A is a member of the plant hemeagglutinin (or plant lectin) family that contains two metal binding sites; one, called S1, is occupied by Mn2+ and the other, S2, by Ca2+. 55Mn electron-nuclear double resonance (ENDOR) measurements were performed on a single crystal of concanavalin A at W-band (95 GHz, ~3.5 T) to determine the 55Mn nuclear quadrupole interaction in a protein binding site and its relation to structural parameters. Such measurements are easier at a high field because of the high sensitivity for size-limited samples and the reduction of second-order effects on the spectrum which simplifies spectral analysis. The analysis of the 55Mn ENDOR rotation patterns showed that two chemically inequivalent Mn2+ types are present at low temperatures, although the high-resolution X-ray structure reported only one site. Their quadrupole coupling constants, e2Qq/h, are significantly different; 10.7 +/- 0.6 MHz for Mand only -2.7 +/-0.6 MHz for M. The ENDOR data also refined the hyperfine coupling determined earlier by single-crystal EPR measurements, yielding a small but significant difference between the two: -262.5 MHz for M and -263.5 MHz for M. The principal z-axis for M is not aligned with any of the Mn-ligand directions, but is 25 off the Mn-asp10 direction, and its orientation is different than that of the zero-field splitting (ZFS) interaction. Because of the small quadrupole interaction of M the orientation dependence was very mild, leading to larger uncertainties in the asymmetry parameter. Nonetheless, there too z is not along the Mn-ligand bonds and is rotated 90 with respect to MnA. These results show, that similar to the ZFS, the quadrupolar interaction is highly sensitive to small differences in the coordination sphere of the Mn2+, and the resolution of the two types is in agreement with the earlier observation of a two-site conformational dynamic detected through the ZFS interaction, which is frozen out at low temperatures and averaged at room temperature. To account for the structural origin of the different e2Qq/h values, the electric field gradient tensor was calculated using the point-charge model. The calculations showed that a relatively small displacement of the oxygen ligand of asp10 can lead to differences on the order observed experimentally. PMID:17408266

Narasimhulu, Kuppala V; Carmieli, Raanan; Goldfarb, Daniella

2007-04-05

444

Factorial Experimental Designs Elucidate Significant Variables Affecting Data Acquisition on a Quadrupole Orbitrap Mass Spectrometer  

NASA Astrophysics Data System (ADS)

Instrument parameter values for a quadrupole Orbitrap mass spectrometer were optimized for performing global proteomic analyses. Fourteen factors were evaluated for their influence on data-dependent acquisition with an emphasis on both the rate of sequencing and spectral quality by maximizing two individually tested response variables (unique peptides and protein groups). Of the 14 factors, 12 factors were assigned significant contrast values ( P < 0.05) for both response variables. Fundamentally, when optimizing parameters, a balance between spectral quality and duty cycle needs to be reached in order to maximize proteome coverage. This is especially true when using a data-dependent approach for sequencing complex proteomes. For example, maximum ion injection time, automatic gain control settings, and minimum threshold settings for triggering MS/MS isolation and activation all heavily influence ion signal, the number of spectra collected, and spectral quality. To better assess the effect these parameters have on data acquisition, all MS/MS data were parsed according to ion abundance by calculating the percent of the AGC target reached for each MS/MS event and then compared with successful peptide-spectrum matches. This proved to be an effective approach for understanding the effect of ion abundance on successful peptide-spectrum matches and establishing minimum ion abundance thresholds for triggering MS/MS isolation and activation.

Randall, Shan M.; Cardasis, Helene L.; Muddiman, David C.

2013-10-01

445

Factorial experimental designs elucidate significant variables affecting data acquisition on a quadrupole orbitrap mass spectrometer.  

PubMed

Instrument parameter values for a quadrupole Orbitrap mass spectrometer were optimized for performing global proteomic analyses. Fourteen factors were evaluated for their influence on data-dependent acquisition with an emphasis on both the rate of sequencing and spectral quality by maximizing two individually tested response variables (unique peptides and protein groups). Of the 14 factors, 12 factors were assigned significant contrast values (P?understanding the effect of ion abundance on successful peptide-spectrum matches and establishing minimum ion abundance thresholds for triggering MS/MS isolation and activation. PMID:23913023

Randall, Shan M; Cardasis, Helene L; Muddiman, David C

2013-08-03

446

Fluorescence Imaging for Visualization of the Ion Cloud in a Quadrupole Ion Trap Mass Spectrometer  

NASA Astrophysics Data System (ADS)

Laser-induced fluorescence is used to visualize populations of gaseous ions stored in a quadrupole ion trap (QIT) mass spectrometer. Presented images include the first fluorescence image of molecular ions collected under conditions typically used in mass spectrometry experiments. Under these "normal" mass spectrometry conditions, the radial (r) and axial (z) full-width at half maxima (FWHM) of the detected ion cloud are 615 and 214 ?m, respectively, corresponding to ~6 % of r 0 and ~3 % of z 0 for the QIT used. The effects on the shape and size of the ion cloud caused by varying the pressure of helium bath gas, the number of trapped ions, and the Mathieu parameter q z are visualized and discussed. When a "tickle voltage" is applied to the exit end-cap electrode, as is done in collisionally activated dissociation, a significant elongation in the axial, but not the radial, dimension of the ion cloud is apparent. Finally, using spectroscopically distinguishable fluorophores of two different m/z values, images are presented that illustrate stratification of the ion cloud; ions of lower m/z (higher q z ) are located in the center of the trapping region, effectively excluding higher m/z (lower q z ) ions, which form a surrounding layer. Fluorescence images such as those presented here provide a useful reference for better understanding the collective behavior of ions in radio frequency (rf) trapping devices and how phenomena such as collisions and space-charge affect ion distribution.

Talbot, Francis O.; Sciuto, Stephen V.; Jockusch, Rebecca A.

2013-10-01

447

Collision cell pressure effect on CID spectra pattern using triple quadrupole instruments: a RRKM modeling.  

PubMed

Control of the ion internal energy in mass spectrometry is needed to establish a workable mass spectral library. The purpose of this study is to understand and to compare the pressure effects on the collision-induced dissociation (CID) spectrum pattern recorded using triple quadrupole instruments. The monoprotonated Leucine enkephalin [YGGFL, H(+)] was used as a thermometer molecule to calibrate the electrospray ionization (ESI) and the CID internal energies deposited on the molecular species and the time scale of ion decompositions. The survival yield and the ratio of a(4)/b(4) fragment ions were mainly monitored. The energy uptake for the ESI source geometry used in our study has no impact on the CID spectrum fingerprint. The collision cell pressure for the [YGGFL, H(+)] has a major influence on the SY curves slope and on the experimental time scale. To demonstrate the pressure effect on internal energy distribution, three models (threshold, thermal and collisional) based on RRKM theory were built using the Masskinetics software. As a result, the limit of each model is discussed, and the investigation demonstrates that the thermal model, using truncated Maxwell-Boltzmann internal energy distribution, is well-suited for simulating the experimental data at high pressure widely used in the analytical conditions. PMID:23378090

Ichou, Farid; Lesage, Denis; Machuron-Mandard, Xavier; Junot, Christophe; Cole, Richard B; Tabet, Jean-Claude

2013-02-01

448

Linear trap with three orthogonal quadrupole fields for dust charging experiments.  

PubMed

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(-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. PMID:23206100

Beránek, Martin; ?ermák, Ivo; N?me?ek, Zden?k; Šafránková, Jana; Je?áb, Martin; Pavl?, Ji?í

2012-11-01

449

Quadrupole and hexadecapole correlations in rotating nuclei studied within the single-j shell model  

NASA Astrophysics Data System (ADS)

The influence of quadrupole and hexadecapole residual interactions on rotational bands is investigated in a single-j shell model. An exact shell-model diagonalization of the quadrupole-plus-hexadecapole Hamiltonian demonstrates that the hexadecapole-hexadecapole interaction can sometimes produce a staggering of energy levels in the yrast sequence; however, long and regular ?I=2 sequences are not obtained. The shell-model results are discussed in terms of the intrinsic deformations extracted by means of the self-consistent Hartree-Fock method. The angular momentum dependence of intrinsic quadrupole and hexadecapole moments Q2? and Q4? is investigated.

Magierski, P.; Burzy?ski, K.; Perli?ska, E.; Dobaczewski, J.; Nazarewicz, W.

1997-03-01

450

Measurement of time dependent fields in high gradient superconducting quadrupoles for the Tevatron  

SciTech Connect

Magnetic field measurements have been performed on prototype and production magnets from two high gradient superconducting quadrupoles designs. One design is a double shell quadrupole with 36 strand Rutherford cable. The other design is a single shell quadrupole with 5 individually monolithic strands connected in series. These magnets have similar bore diameters and cable dimensions. However, there are significant differences between the two designs, as well as differences between prototype and production magnets within each design, with regard to Cu to superconductor ratio, filament diameter and filament spacing to strand diameter. The time dependence of fixed currents of the measured magnetic fields is discussed. 9 refs., 6 figs., 1 tab.

Lamm, M.J.; Coulter, K.; Gourlay, S.; Jaffery, T.S.

1990-10-01

451

Production techniques for the superconducting super collider low energy booster quadrupole magnet  

NASA Astrophysics Data System (ADS)

The manufacturing techniques used for a prototype quadrupole magnet, developed at Lawrence Berkeley Laboratory (LBL) for the Superconducting Super Collider (SSC) Low Energy Booster (LEB), are described. The SSC LEB Ring employs 96 dipoles and 90 quadrupoles connected in series to form the magnetic lattice, requiring the use of a 21.9 mm x 23.0 mm hollow conductor for the quadrupoles. Due to the large conductor size and small bend radii required, development of special fixtures was necessary. A unique coil-forming method with close attention paid to tooling design and special assembly procedures was required to manufacture this prototype to stringent specifications.

Morrison, Michael E.; Behrsing, Gerd U.; Fulton, Robert L.

1994-07-01

452

On the dipole and quadrupole kinematic anisotropy in the brightness of the cosmic background radiation  

SciTech Connect

This paper studies the dipole and quadrupole anisotropy brightness arising from the motion of the observer in the presence of a pure Planckian spectrum and in the case of a submillimeter excess. It is found that the dipole anisotropy is enhanced in the case of the excess measured by the Japanese-U.S. groups, while it is decreased in the case of the excess found by the Canadian group. The quadrupole term is absent in the radio region, while it acquires detectable values in the IR. Comparisons are made with the observational values, and the possibility of observing the quadrupole pattern in the presence of galactic dust contamination is discussed. 15 refs.

De Bernardis, P.; Epifani, M.; Guarini, G.; Masi, S.; Melchiorri, F. (Roma I Universita, Rome (Italy))

1990-04-01

453

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

454

The electric field gradient tensor and the tensors of the molecular magnetic susceptibility and the molecular electric quadrupole moment in nitric acid: A high-resolution rotational Zeeman effect study  

Microsoft Academic Search

High-resolution zero field and Zeeman rotational spectra have been studied for HNO3 and DNO3. The measured values for the 14N nuclear quadrupole coupling constants are chi+ = chibb + chicc = -0.929(6) MHz and chi- = chibb - chicc = -0.789(10) MHz for HNO3 and chi+ = 0.731(6) MHz and chi- = -0.576(10) MHz for DNO3. The measured molecular g

L. Albinus; J. Spieckermann; D. H. Sutter

1989-01-01

455

Quadrupole Lense Field Potential Determination by the Boundary Integral Equation Method.  

National Technical Information Service (NTIS)

Numerical method for investigating the effect of small disturbances in quadrupole magnetic lense piece configuration on the field potential is proposed. The problem of field potential determination is reduced to a boundary integral equation. The method of...

V. P. Akopyan G. K. Sarkisyan L. A. Smirnova

1985-01-01

456

Numerical Simulation of a Magnetic Field in Superconducting Quadrupoles for Nuclotron.  

National Technical Information Service (NTIS)

A magnetic field in superconducting quadrupoles of relativistic nuclei has been numerically modelled. The spatial field has been calculated by the method of volume integral equations using the system of MAGSYS programs and the central field by the conjuga...

Z. V. Borisovskaya E. P. Zhidkov A. A. Smirnov L. A. Smirnova I. A. Shelaev

1988-01-01

457

Quadrupole Antishielding Factors for Rare-Earth and Some Other Heavy Ions.  

National Technical Information Service (NTIS)

Sternheimer quadrupole antishielding factors are reported for several rare-earth ions and for several ions isoelectronic with I(-) and Br(-). Radial excitations were obtained using the selfconsistent-field unrestricted Hartree-Fock method described previo...

R. E. Watson A. J. Freeman

1964-01-01

458

Evaluation of the ground-state quadrupole moments of the ?(sd) nuclei  

NASA Astrophysics Data System (ADS)

The current diversity and inconsistency among published quadrupole moments calls for a thorough evaluation of the available data. In this work, a review of the ground-state Q-moments of the oxygen to calcium isotopes is presented, resulting in a revised database of 43 quadrupole moments. For every ?(sd) isotope chain, the quadrupole moments are expressed relative to one reference isotope. This common reference rules out the existing arbitrariness and provides a reliable basis for future measurements and theoretical studies. In addition, the evaluated quadrupole-moment values are compared to shell-model calculations, obtained with different effective interactions in the sd and sdpf model spaces and using the standard effective charges ep=1.3e and en=0.5e. The discrepancy between theory and experiment, observed for particular isotopes and isotope chains, calls for further fundamental research.

De Rydt, M.; Depuydt, M.; Neyens, G.

2013-07-01

459

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

460

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

461

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

462

DEVELOPMENT AND TEST OF COLLARING METHODS FOR Nb{sub 3}SN QUADRUPOLE MAGNETS  

SciTech Connect

Fermilab is developing Nb{sub 3}Sn quadrupole magnets for the planned upgrade of interaction regions of the Large Hadron Collider (LHC). Two distinctly different approaches have been employed, one using quadrupole-symmetric and one using dipole-symmetric collar laminations. This paper describes the design features of both collar types, collaring techniques for brittle Nb{sub 3}Sn coils, and compares the advantages and disadvantages of the two approaches. Results of mechanical analysis for quadrupoles based on dipole-type and quadrupole-type collars are presented. Magnet construction issues and test results are reported. Test results include coil and component strain measurements during construction. Plans for the completion and test of the first dipole-symmetric assembly are described.

Bossert, R.; Ambrosio, G.; Andreev, N.; Chlachidze, G.; Kashikhin, V. V.; Lamm, M.; Nobrega, F.; Novitski, I.; Tartaglia, M.; Yu, M.; Zlobin, A. V. [Fermi National Accelerator Laboratory, Batavia, Il. 60510 (United States)

2010-04-09

463

Magnetic Design of a High Gradient Quadrupole for the LHC Low-Beta Insertions.  

National Technical Information Service (NTIS)

Fermilab, Lawrence Berkeley National Laboratory and Brookhaven National Laboratory have formed a consor- tium to provide components for the Large Hadron Collider (LHC) to be built at CERN. The U.S. contribution includes half of the high gradient quadrupol...

G. Sabbi S. A. Gourlay J. Kerby M. J. Lamm P. J. Limon

2002-01-01

464

Pairing versus quadrupole collectivity of low-lying 0+ states in deformed nuclei  

SciTech Connect

The low-lying 0+ states observed in large abundance in several deformed nuclei are investigated systematically within the microscopic quasiparticle-phonon model. Attention is paid at their quadrupole and pairing collective properties.

Lo Iudice, N. [Universita di Napoli Federico II, Dipartimento di Scienze Fisiche, Monte S. Angelo, via Cintia, I-80126 Naples (Italy); Sushkov, A. V.; Shirikova, N. Yu. [Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation)

2006-03-13

465

Open problems in understanding the nuclear chirality  

NASA Astrophysics Data System (ADS)

Open problems in the interpretation of the observed pair of near-degenerate ?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 the particle rotor model (PRM). Future developments of the theoretical approach are anticipated.

Meng, Jie; Zhang, S. Q.

2010-06-01

466

Understanding and Using Statistics in Nuclear Medicine  

Microsoft Academic Search

Because statistics is, in a sense, the heart of the scientific method, and because the field of statis­ tics, beginning with Karl Pearson and R. A. Fisher, has developed for the specific purpose of aiding the scientist to make valid inferences, a brief review of the scientific method, research, and the role of sta­ tistics seems in order. When working

Sheldon G. Levin

467

Nuclear magnetic resonance of 209Bi in a BiVO4 single crystal  

Microsoft Academic Search

Nuclear magnetic resonance spectra of 209Bi(I=9\\/2) in the ferroelastic BiVO4 single crystal has been investigated by employing a wide-line Varian spectrometer. Only three lines due to a large quadrupole interaction were measured at a fixed frequency of 6 MHz in the principal planes at room temperature. From the experimental data the quadrupole coupling constant E2qQ\\/h=79.2+or-0.1 MHz and asymmetry parameter eta

A. R. Lim; S. H. Choh; M. S. Jang

1992-01-01

468

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

469

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