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1

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

2

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

3

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

4

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

5

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 CCl in more than 20 clathrates have been measured in the range 4-200 K. The crystal structures of CCl\\/Dianin's compound (1), CCl\\/Fe(AcAc) (3), CCl\\/Ni(SCN)(3-MePy) (4), and CCl\\/Ni(exan)(4,4-dm-2,2-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

6

Quadrupole coupling parameters and structural aspects of crystalline and amorphous solids by NMR and NQR  

SciTech Connect

NMR and NQR techniques were 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. {sup 71}Ga and {sup 69}Ga NMR was used to study crystalline {beta}-Ga{sub 2}O{sub 3} and several gallate glasses. Quadrupole parameters were acquired for GaO{sub 6} and GaO{sub 4} units in {beta}-Ga{sub 2}O{sub 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. {sup 51}V (I = 7/2) NQR resonances below 850 kHz were detected for several metavanadates at both room temperature and liquid nitrogen temperature. Two methods, Zeeman perturbed NQR powder pattern and {sup 10}B NQR, can be employed to obtain both Qcc and {eta}. With a double coil tank circuit design, pure {sup 11}B NQR was used to determine the fraction of borons in BO{sub 3} and BO{sub 4} configurations in hydrated zinc borates. {sup 11}B NMR and NQR were also used to study lead borate glasses.

Mao, Degen.

1991-01-01

7

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

8

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

9

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

10

Structureactivity study of thiazides by magnetic resonance methods (NQR, NMR, EPR) and DFT calculations  

Microsoft Academic Search

The paper presents a comprehensive analysis of the relationship between the electronic structure of thiazides and their biological activity. The compounds of interest were studied in solid state by the resonance methods nuclear quadrupole resonance (NQR), nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) and quantum chemistry (ab inito and DFT) methods. Detailed parallel analysis of the spectroscopic parameters

J. N. Latosi?ska

2005-01-01

11

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

12

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

13

A correlation of spectroscopic parameters from different magnetic resonance spectroscopies for thiazides: a study by NQR, NMR, EPR and DFT methods  

Microsoft Academic Search

A Letter is devoted to a detailed parallel analysis of the spectroscopic parameters such as quadrupole coupling constant (NQR), chemical shift, chemical shift anisotropy, asymmetry parameter (NMR) and hyperfine coupling constant (EPR) for thiazides. The compounds were studied in solid state by the resonance (NQR, NMR and EPR) and density functional theory (DFT) methods. The spectroscopic parameters determined at room

J. N. Latosi?ska

2004-01-01

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

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

17

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

18

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

19

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

20

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

21

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

22

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

23

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

24

Factors affecting the NQR line width in nitramine explosives  

Microsoft Academic Search

A number of factors associated with crystal quality contribute to the nuclear quadrupole resonance (NQR) line width. Imperfections\\u000a such as dislocations, voids, strain and impurities can be electrical sources that distort the electric field gradient at nearby\\u000a quadrupolar nuclei and broaden the observed NQR line. We measured the14N NQR line widths in powdered samples of the nitramine explosives hexahydro-1,3,5-trinitro-s-triazine (RDX),

M. L. Buess; S. M. Caulder

2004-01-01

25

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

26

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

27

14 N NQR spectra of complexes between hexamethylenetetramine and the crystalline hydrates of salts  

Microsoft Academic Search

Nuclear quadrupole resonance has recently been used more and more effective along with such traditional methods as vibrational spectroscopy and proton magnetic resonance to investigate hydrogen bonding. The NQR method on 14N nuclei has been put into practice at a later date than on the chlorine nuclei. This is explained by the low intensity of the 14N NQR signals and

. O. Azizov; V. S. Grechishkin; T. G. Balicheva; I. V. Pologikh

1979-01-01

28

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

29

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

30

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

31

Semiempirical quantum mechanical calculations of electronic distribution and NQR parameters of bromine atoms in some organic and inorganic compounds  

Microsoft Academic Search

The Br electric field gradient (EFG) for some organic and inorganic compounds was calculated using a semi-empirical method. The nuclear quadrupole resonance (NQR) frequencies and asymmetry parameters of the bromine atoms in these compounds have also been evaluated. Quantitative correlation of the NQR frequencies and asymmetry parameters of the EFG of bromine nuclei with the population of p orbitals of

N. L Hadipour; S Javadian

2000-01-01

32

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.; agar, V.; Zidanek, A.; Blinc, R.

2006-12-01

33

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.; agar, V.

2008-07-01

34

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

35

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

36

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

37

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

38

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

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

2005-07-14

39

Sb NQR in filled skutterudites MFe 4Sb 12 (M=Na, Ca, La)  

Microsoft Academic Search

Temperature-dependent nuclear quadrupole resonance (NQR) investigations on the 121,123Sb nuclei in filled skutterudites MFe4Sb12 (M=Na, Ca, La) are reported. These new compounds show a nice interplay of ferromagnetic and antiferromagnetic correlations best seen in the relaxation rate. Substructures observed in the 121,123Sb NQR spectra give strong evidence for static (or dynamic) disorder on the filler site. Therefore, we performed ab-initio

A. A. Gippius; E. N. Morozova; K. S. Okhotnikov; E. A. Alkaev; A. V. Shevelkov; M. Baenitz; A. Leithe-Jasper; H. Rosner; R. Viennois; Yu. Grin; F. Steglich

2006-01-01

40

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

41

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

PubMed

?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, Toma

2013-06-04

42

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

43

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

44

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

45

Off-resonance effects and selectivity profiles in pulsed nitrogen-14 nuclear quadrupole resonance.  

PubMed

In order to alleviate base-line distortions in nitrogen-14 NQR spectra originating from pulse breakthrough, low power radio-frequency (rf) pulses were applied. It is recalled that the required power is four times lower than that for an equivalent NMR experiment. This is easily explained by the fact that, in NMR, half the amplitude of the rf field is active. Moreover, the selectivity profile (i.e. the peak amplitude as a function of the difference between the carrier frequency and the resonance frequency) exhibits a shape which is, in most cases, more favorable in NQR than in NMR. An appropriate theory has been developed for explaining these experimental observations. It is concluded that low power NQR is perfectly feasible and should even be recommended for most applications, provided that the line-width of the NQR signal is not too large. PMID:23063174

Guendouz, L; Robert, A; Retournard, A; Leclerc, S; Aissani, S; Canet, D

2012-09-01

46

Determination of the electric field gradient tensor by 2D NQR  

Microsoft Academic Search

For a full specification of the Electric Field Gradient (EFG) tensor, five independent parameters are necessary: the asymmetry parameter (?), the largest component of the EFG (eq), and three angles which determine the orientation of the EFG principal axis with respect to the crystallographic frame. The parameters eq and ? can be determined independently by pure Nuclear Quadrupole Resonance (NQR)

C. R. Hernn; S. R. Rabbani; Christovam Mendona

1997-01-01

47

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

48

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

49

Signal processing for NQR discrimination of buried land mines  

NASA Astrophysics Data System (ADS)

Nuclear quadrupole resonance (NQR) is a technique that discriminates mines from clutter by exploiting unique properties of explosives, rather than the attributes of the mine that exist in many forms of anthropic clutter. After exciting the explosive with a properly designed electromagnetic-induction (EMI) system, one attempts to sense late-time spin echoes, which are characterized by radiation at particular frequencies. It is this narrow-band radiation that indicates the presence of explosives, since this effect is not seen in most clutter, both natural and anthropic. However, this problem is complicated by several issues. First, the late-time radiation if often very weak, particularly for TNT, and therefore the signal-to-noise ratio must be high for extracting the NQR response. Further, the frequency at which the explosive radiates is often a strong function of the background environment, and therefore in practice the NQR radiation frequency is not known a priori. Finally, at the frequencies of interest, there is a significant amount of background radiation, which induces radio frequency interference (RFI). In this paper we discuss several signal processing tools we have developed to enhance the utility of NQR explosives detection. In particular, with regard to the RFI, we exposure least-mean-squares algorithms which have proven well suited to extracting background interference. Algorithm performance is assessed through consideration of actual measured data. With regard to the detection of the NQR electromagnetic echo, we consider a Bayesian discrimination algorithm. The performance of the Bayesian algorithm is presented, again using measured NQR data.

Tantum, Stacy L.; Collins, Leslie M.; Carin, Lawrence; Gorodnitsky, Irina; Hibbs, Andrew D.; Walsh, David O.; Barrall, Geoffrey A.; Gregory, Dave; Matthews, Robert; Vierkoetter, Stephie A.

1999-08-01

50

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

51

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 TA40 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

52

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

53

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

54

Application of a dc SQUID to rf amplification: NQR  

SciTech Connect

Superconducting QUantum Interference Devices (SQUIDs) have been used for more than a decade for the detection of magnetic resonance. Until recently, these devices had mostly been confined to operation in the audiofrequency range, so that experiments have been restricted to measurements of resonance at low frequencies, or of changes in the static susceptibility of a sample induced by rf irradiation at the resonant frequency. However, the recent extension of the operating range of low noise dc SQUIDs to radiofrequencies (rf) allows one to detect magnetic resonance directly at frequencies up to several hundred megahertz. In this paper, we begin by summarizing the properties of dc SQUIDs as tuned rf amplifers. We then describe first, the development of a SQUID system for the detection of pulsed nuclear quadrupole resonance (NQR) at about 30 MHz and second, a novel technique for observing magnetic resonances in the absence of any externally applied rf fields.

Hilbert, C.; Clarke, J.; Sleator, T.; Hahn, E.L.

1985-05-01

55

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

56

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

57

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

58

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 297380K 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

59

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

60

35Cl-NQR and DFT study of electronic structure of amlodipine and felodipine vascular-selective drugs from the dihydropyridine Ca ++ antagonists group  

NASA Astrophysics Data System (ADS)

Amlodipine (AM) and felodipine (FL) have been studied in solid state by the nuclear quadrupole resonance (NQR) and density functional theory (DFT). The results have shown that NQR data do not permit a differentiation between R and S enantiomers, which is a consequence of the symmetry of the 4-aryl ring, whereas they permit a differentiation between free bases and salts. The HOMO-LUMO gap is smaller for AM than for FL, which suggests smaller energy of excitation for AM. The absolute hardness, chemical potential and electrophilicity of both AM enantiomers are lower than the corresponding values for FL enantiomers, suggesting that AM should be more reactive than FL in unimolecular reactions.

Latosi?ska, J. N.; Latosi?ska, M.; Kasprzak, J.

2008-09-01

61

NQR investigation and characterization of cocrystals and crystal polymorphs  

NASA Astrophysics Data System (ADS)

The application of 14N NQR to the study of cocrystals and crystal polymorphs is reviewed. In ferroelectric and antiferroelectric organic cocrystals 14N NQR is used to determine proton position in an N-H...O hydrogen bond and proton displacement below TC. In cocrystal isonicitinamide - oxalic acid (2:1) 14N NQR is used to distinguish between two polymorphs and to determine the type of the hydrogen bond (N-...H-O). The difference in the 14N NQR spectra of cocrystal formers and cocrystal is investigated in case of carbamazepine, saccharin and carbamazepine - saccharin (1:1). The experimental resolution allows an unambiguous distinction between the 14N NQR spectrum of the cocrystal and the 14N NQR spectra of the cocrystal formers. The possibility of application of NQR and double resonance for the determination of the inhomogeneity of the sample and for the study of the life time of an unstable polymorph is discussed.

Seliger, Janez; agar, Veselko; Asaji, Tetsuo

2013-05-01

62

(75)As, (63)Cu NMR and NQR characterization of selected arsenic minerals.  

PubMed

The direct measurement and identification of solid state arsenic phases using (75)As NMR is made difficult by the simultaneous conditions of large quadrupole moment and low coordination symmetry in many compounds. However, specific arsenic minerals can efficiently be detected and discriminated via nuclear quadrupolar resonance (NQR). We report on the first NMR and NQR measurements in the natural minerals enargite (Cu3AsS4), niccolite (NiAs), arsenopyrite (FeAsS) and loellingite (FeAs2). The NQR frequencies have been determined from both high-field NMR powder patterns and via zero-field frequency sweeps. Density functional theory (DFT) based ab initio calculations support the experimental results. The compounds studied here are common in terms of the known set of As-containing minerals. They are sometimes encountered in the context of base metal or gold mining. The study represents a significant addition to the list of arsenic minerals that can now be detected with NQR techniques. PMID:23706610

Lehmann-Horn, J A; Miljak, D G; Bastow, T J

2013-05-14

63

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.

Nadja, H.; Quentin, P.

2012-06-01

64

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

65

Electronic structure and biological activity of chosen DDT-type insecticides studied by 35Cl-NQR.  

PubMed

A correlation between the electronic structure and biological activity of chosen dichlorodiphenyltrichloroethane (DDT)-type insecticides: 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane, 1,1-dichloro-2,2-bis(4-chlorophenyl)ethane, 2,2-bis(p-chlorophenyl)-1,1-dichloroethylene, 2,2-bis(4-chlorophenyl)ethanoic acid and 4,4'-dichlorobenzophenone (used in agriculture) has been analysed on the basis of the (35)Cl-nuclear quadrupole resonance (NQR) spectroscopy. The (35)Cl-NQR resonance frequencies measured at 77 K have been correlated with the lethal dose (LD(50)) parameter that characterises the biological activity of these insecticides. PMID:18942076

Jadzyn, Maciej; Nogaj, Boles?aw

2009-02-01

66

Sb NQR study of the filled skutterudite CeFe4Sb12 synthesized under high pressure  

NASA Astrophysics Data System (ADS)

We report the results of Sb nuclear quadrupole resonance (NQR) measurements on the filled skutterudite CeFe4Sb12 synthesized under high pressure (HP) and compare them with those for the sample synthesized under ambient pressure (AP) to understand the influence of the Ce-site filling fraction. The NQR spectra for the HP sample are much sharper than those for the AP sample, suggesting that the Ce filling fraction is higher. Also, the nuclear spin-lattice relaxation rate 1/ T 1 follows an exponential decrease 1/ T 1 ? exp(-?/ k B T), with the gap being ?/ k B = 270 K at temperatures above 100 K, which is larger than that for the AP sample. This result suggests that the c- f hybridization is enhanced by increasing the Ce-site filling fraction.

Magishi, Ko-ichi; Takahashi, Masahiro; Saito, Takahito; Koyama, Kuniyuki; Sugawara, Hitoshi; Saito, Takashi; Tatsuoka, Sho; Tanaka, Kenya; Sato, Hideyuki

2013-08-01

67

Ab initio DFT study of bisphosphonate derivatives as a drug for inhibition of cancer: NMR and NQR parameters.  

PubMed

DFT computations were carried out to characterize the (17)Oand (2)H electric field gradient, EFG, in various bisphosphonate derivatives. The computations were performed at the B3LYP level with 6-311++G (d,P) standard basis set. Calculated EFG tensors were used to determine the (17)O and (2)H nuclear quadrupole coupling constant, ? and asymmetry parameter, ?. For better understanding of the bonding and electronic structure of bisphosphonates, isotropic and anisotropic NMR chemical shieldings were calculated for the (13)C, (17)O and (31)P nuclei using GIAO method for the optimized structure of intermediate bisphosphonates at B3LYP level of theory using 6-311++G (d, p) basis set. The results showed that various substituents have a strong effect on the nuclear quadrupole resonance (NQR) parameters (?, ?) of (17)O in contrast with (2)H NQR parameters. The NMR and NQR parameters were studied in order to find the correlation between electronic structure and the activity of the desired bisphosphonates. In addition, the effect of substitutions on the bisphosphonates polarity was investigated. Molecular polarity was determined via the DFT calculated dipole moment vectors and the results showed that substitution of bromine atom on the ring would increase the activity of bisphosphonates. PMID:21633790

Aghabozorg, Hussein; Sohrabi, Beheshteh; Mashkouri, Sara; Aghabozorg, Hamid Reza

2011-06-02

68

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

69

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

70

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-HN 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-HN 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 HA (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; agar, Veselko

2013-05-29

71

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

72

Quadrupole resonances in the rare-earth metals  

SciTech Connect

Calculations that employ a relativistic time-dependent local-density approximation to atomic absorption are used to examine a recent claim to the observation of giant quadrupolar resonances in the electron-energy-loss spectrum of Ce metal near the 4p edge. We confirm the existence of 4p..-->..4f resonances in this energy range but find the polarization effects much smaller than in typical giant dipole resonances.

Liberman, D.; Zangwill, A.

1989-01-01

73

Electronic properties of LaO1-xFxFeAs in the normal state probed by NMR/NQR  

NASA Astrophysics Data System (ADS)

We report 139La, 57Fe and 75As nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements on powders of the new LaO1-xFxFeAs superconductor for x=0 and 0.1 at temperatures up to 480 K, and compare our measured NQR spectra with local density approximation (LDA) calculations. For all three nuclei in the x=0.1 material, it is found that the local Knight shift increases monotonically with an increase in temperature, and scales with the macroscopic susceptibility, suggesting a single magnetic degree of freedom. Surprisingly, the spin lattice relaxation rates for all nuclei also scale with one another, despite the fact that the form factors for each site sample different regions of q-space. This result suggests a lack of any q-space structure in the dynamical spin susceptibility that might be expected in the presence of antiferromagnetic correlations. Rather, our results are more compatible with simple quasi-particle scattering. Furthermore, we find that the increase in the electric field gradient at the As cannot be accounted for by LDA calculations, suggesting that structural changes, in particular the position of the As in the unit cell, dominate the NQR response.

Grafe, H.-J.; Lang, G.; Hammerath, F.; Paar, D.; Manthey, K.; Koch, K.; Rosner, H.; Curro, N. J.; Behr, G.; Werner, J.; Leps, N.; Klingeler, R.; Klauss, H.-H.; Litterst, F. J.; Bchner, B.

2009-03-01

74

35Cl quadrupole resonance study of the thermally activated motion of the nitro group in chlorinated nitrobenzenes  

NASA Astrophysics Data System (ADS)

The results of NQR studies of the thermoactivated motion of NO2 groups in chlorine-containing nitrobenzenes are presented. A procedure for analyzing the experimental data is suggested. It uses the characteristic temperature of the minimum of the modulation contribution to the temperature dependence of the spin-lattice relaxation time T 1 of the resonant probe nuclei (35Cl) bonded with the moving group by nonvalent interactions. The activation energy of the thermoactivated motion was correlated with the temperature of the minimum. The possibility of a temperature dependence of the activation energy of the NO2 group was examined.

Kyuntsel, I. A.

2013-05-01

75

Possible stripe fluctuations in La2 - x - yNdySrxCuO4 at room temperature observed by 63Cu NQR spectroscopy  

NASA Astrophysics Data System (ADS)

63Cu nuclear quadrupole resonance (NQR) studies at room temperature were reported on six Nd-doped La2 - xSrxCuO4 samples. The NQR spectrum for La1.48Nd0.4Sr0.12CuO4 has a different line shape compared with those from the other samples, which is similar to the case of the insulating La2CuO4. This may suggest that the stripe fluctuations at such a special Nd and Sr doping fall into the frequency window of 63Cu NQR. The spectra of the other five samples were analysed by pairs of 63Cu and 65Cu Gaussians at A and B sites. The full width of half-maxim (FWHM) for 63Cu at B sites is anomalously large for La1.45Nd0.4Sr0.15CuO4, which was considered to be related to the stripe fluctuations.

Zhang, Q.-M.; Ying, X. N.; Gu, M.; Wang, Y. N.

2005-04-01

76

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

77

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

78

NMR and NQR parameters of the SiC-doped on the (4,4) armchair single-walled BPNT: a computational study.  

PubMed

The structural properties, NMR and NQR parameters in the pristine and silicon carbide (SiC) doped boron phosphide nanotubes (BPNTs) were calculated using DFT methods (BLYP, B3LYP/6-31G) in order to evaluate the influence of SiC-doped on the (4,4) armchair BPNTs. Nuclear magnetic resonance (NMR) parameters including isotropic (CS(I)) and anisotropic (CS(A)) chemical shielding parameters for the sites of various (13)C, (29)Si, (11)B, and (31)P atoms and quadrupole coupling constant (C ( Q )), and asymmetry parameter (? ( Q )) at the sites of various (11)B nuclei were calculated in pristine and SiC- doped (4,4) armchair boron phosphide nanotubes models. The calculations indicated that doping of (11)B and (31)P atoms by C and Si atoms had a more significant influence on the calculated NMR and NQR parameters than did doping of the B and P atoms by Si and C atoms. In comparison with the pristine model, the SiC- doping in Si(P)C(B) model of the (4,4) armchair BPNTs reduces the energy gaps of the nanotubes and increases their electrical conductance. The NMR results showed that the B and P atoms which are directly bonded to the C atoms in the SiC-doped BPNTs have significant changes in the NMR parameters with respect to the B and P atoms which are directly bonded to the Si atoms in the SiC-doped BPNTs. The NQR results showed that in BPNTs, the B atoms at the edges of nanotubes play dominant roles in determining the electronic behaviors of BPNTs. Also, the NMR and NQR results detect that the Fig. 1b (Si(P)C(B)) model is a more reactive material than the pristine and the Fig. 1a (Si(B)C(p)) models of the (4,4) armchair BPNTs. PMID:21625895

Baei, Mohammad T; Sayyad-Alangi, S Zahra; Moradi, Ali Varasteh; Torabi, Parviz

2011-05-28

79

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

80

A High-Efficiency Resonant Cavity for Measurement of a Beam Quadrupole Moment  

SciTech Connect

Many particle accelerator applications can benefit from online pulse-by-pulse nonintercepting emittance measurement system. Recently, there has been much interest in performing such a measurement with a set of resonant quadrupole-mode cavities. This article explores a geometry to achieve an enhanced shunt impedance in such a cavity by adding a set of posts forming capacitive gaps near the beam pipe outer radius. For typical diagnostic cavity applications, a five-fold increase in shunt impedance can be obtained with this method. The effect of errors in cavity fabrication on the required mode structure are explored.

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

2005-10-26

81

^63Cu NQR relaxation in the p-type transparent conductor CuScO_2:Mg  

NASA Astrophysics Data System (ADS)

Transparent conducting oxides with p-type conductivity are of interest as electronic complements to the more familiar n-type transparent conductors. This paper reports the first results of a study of carrier spin dynamics in p-type CuScO_2:Mg using ^63Cu nuclear spin-lattice relaxation measurements. Relaxation rates 1/T1 have been measured by nuclear quadrupole resonance (NQR) over the range 280 K to 400 K. The ^63Cu NQR frequency is found to be 28,135 5 kHz at 300 K and to decrease linearly with temperature over the experimental range. The value of 1/T1 at 300 K is 130 10 s-1. The rate is weakly dependent on temperature and increases by only about 15 % up to 400 K. This behavior contrasts sharply with results obtained previously(1. A. Rajabzadeh, J. Tate and W. Warren, Bull. Am. Phys. Soc. 48, 1009 (2003).) for the related material CuYO_2:Ca. In that material, relaxation rates for ^63Cu and ^65Cu were strongly temperature dependent, being approximately thermally-activated with activation energy 152 10 meV. The nuclear relaxation properties of CuScO_2:Mg are suggestive of more conventional metallic transport in CuScO_2:Mg compared with CuYO_2:Ca.

Rossi, Vincent; Tate, Janet; Warren, William; Li, Jun; Sleight, Arthur

2003-05-01

82

Investigation of nuclear quadrupole resonance in the series of bromine- and iodine-containing disubstituted benzenes  

Microsoft Academic Search

The results of Br m and I t27 NOR determinations in the series of disubstituted halobenzenes are given. It Is shown that a correlation, very roughly linear, can be found between the NQR frequencies and the Hammett constant o. The possible causes of the deviations of this relationship from ltnearity are discussed. It is pointed out that the analytical potentialities

G. K. Semin

1962-01-01

83

Antiferromagnetic properties of a water-vapor-inserted YBa2 Cu3 O6.5 compound studied byNMR, NQR, and muSR  

Microsoft Academic Search

We present a detailed NQR, nuclear magnetic resonance (NMR), and muSR study of the magnetic phase obtained during a topotactic chemical reaction of YBa2Cu3O6.5 high-temperature superconductor with low-pressure water vapor. Cu65 -enriched samples have been used for NQR\\/NMR studies which allows to get a good resolution in the Cu(1) NQR and Cu(2) zero field NMR (ZFNMR) spectra. It is shown

A. V. Dooglav; A. V. Egorov; I. R. Mukhamedshin; A. V. Savinkov; H. Alloul; J. Bobroff; W. A. Macfarlane; P. Mendels; G. Collin; N. Blanchard; P. G. Picard; P. J. C. King; J. Lord

2004-01-01

84

Calibration of ion effective temperatures achieved by resonant activation in a quadrupole ion trap.  

PubMed

The present paper describes a calibration of the ion effective temperatures as a function of the resonant activation amplitude in a quadrupole ion trap mass spectrometer. MS/MS experiments are performed on leucine enkephalin (M + H)+, bradykinin (M + H)+, (M + 2H)2+, and (M + 3H)3+, and ubiquitin (M + 11H)11+. For each amplitude, the effective temperature is calculated as the temperature that would give the same dissociation rate constant as the one observed and is calculated using published Arrhenius parameters. The effective temperature is found to be linearly dependent on the activation amplitude on the range investigated. The dependence of the slope and of the intercept of the T(eff) = f (amplitude) functions on the parent ion m/z is examined and an equation is derived to calibrate the ion effective temperature between 365 and 600 K. Below 365 K, a deviation from linearity is expected. Above 600 K, the validity of the equation will depend on whether the rapid energy exchange limit is still reached. Calculating backward, the Arrhenius parameters from the measured dissociation rates using this calibration show excellent agreement with the published values. The calibration can therefore be used to determine Arrhenius activation parameters from dissociation kinetics under resonant activation in quadrupole ion trap mass spectrometers. PMID:14708790

Gabelica, Valrie; Karas, Michael; De Pauw, Edwin

2003-10-01

85

Simplest photonuclear reactions accompanied by the excitation of isovector giant dipole and quadrupole resonances: Semimicroscopic description  

SciTech Connect

A semimicroscopic approach based on the continuum version of the random-phase approximation (CRPA) and on a semiphenomenological inclusion of the fragmentation effect is applied to describing cross sections for photoabsorption and direct plus semidirect and inverse reactions accompanied by the excitation of isovector giant dipole and quadrupole resonances. In addition to the spinless part of the Landau-Migdal interaction and a partly self-consistent phenomenological mean field of the nucleus, that version of the approach which is used here takes into account isovector separable velocity-dependent forces, as well as the effect of the fragmentation shift of the giant-resonance energy. The results obtained by calculating various features of the aforementioned cross sections for a number of magic and semimagic medium-mass nuclei are compared with respective experimental data.

Tulupov, B. A., E-mail: tulupov@cpc.inr.ac.ru [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation); Urin, M. H. [National Research Nuclear University MEPhI (Russian Federation)

2012-09-15

86

Electron cyclotron resonance near the axis of a quadrupole linear trap  

SciTech Connect

The quasi-longitudinal propagation of an extraordinary electromagnetic wave in the vicinity of the electron cyclotron resonance layer in an open linear trap with a quadrupole magnetic field is studied analytically, taking into account the inhomogeneity of the magnetic field in a paraxial approximation. The ray trajectories are derived from a simplified dispersion equation, that is, nonetheless able to accurately describe the transition from finite to zero perpendicular refractive index. A criterion for an on-axis resonance point to be an attractor for the ray trajectories is formulated, which generalizes a similar criterion for axisymmetric linear traps derived in a recent paper [D. S. Bagulov and I. A. Kotelnikov, Phys. Plasmas 19, 082502 (2012)].

Kotelnikov, I. A. [Budker Institute of Nuclear Physics, Lavrentyev Av. 11, Novosibirsk 630090 (Russian Federation); Rome, M. [INFN Sezione di Milano and Dipartimento di Fisica, Universita degli Studi di Milano, Via Celoria 16, I-20133 Milano (Italy)

2012-12-15

87

Electron cyclotron resonance near the axis of a quadrupole linear trap  

NASA Astrophysics Data System (ADS)

The quasi-longitudinal propagation of an extraordinary electromagnetic wave in the vicinity of the electron cyclotron resonance layer in an open linear trap with a quadrupole magnetic field is studied analytically, taking into account the inhomogeneity of the magnetic field in a paraxial approximation. The ray trajectories are derived from a simplified dispersion equation, that is, nonetheless able to accurately describe the transition from finite to zero perpendicular refractive index. A criterion for an on-axis resonance point to be an attractor for the ray trajectories is formulated, which generalizes a similar criterion for axisymmetric linear traps derived in a recent paper [D. S. Bagulov and I. A. Kotelnikov, Phys. Plasmas 19, 082502 (2012)].

Kotelnikov, I. A.; Rom, M.

2012-12-01

88

NMR and NQR Studies on Non-centrosymmetric Superconductors Re7B3, LaBiPt, and BiPd  

NASA Astrophysics Data System (ADS)

We report the nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements for non-centrosymmetric superconductors Re7B3, LaBiPt, and BiPd containing heavy elements. For all three compounds, the spin--lattice relaxation rate 1/T1 shows a coherence peak just below Tc and decreases exponentially at low temperatures, which indicates that an isotropic superconducting gap is dominant in these compounds. In BiPd, the height of the coherence peak just below Tc is much suppressed, which suggests that there exists a substantial component of gap with nodes in this compound. Our results indicate that heavy element is not the only factor, but the extent of inversion symmetry breaking is also important to induce a large spin--orbit coupling and an unconventional superconducting state.

Matano, Kazuaki; Maeda, Satoki; Sawaoka, Hiroki; Muro, Yuji; Takabatake, Toshiro; Joshi, Bhanu; Ramakrishnan, Srinivasan; Kawashima, Kenji; Akimitsu, Jun; Zheng, Guo-qing

2013-08-01

89

Measurement of the Isovector Giant Quadrupole Resonance of ^89Y at HI?S  

NASA Astrophysics Data System (ADS)

The isovector giant quadrupole resonance (IVGQR) is challenging to characterize due to its broad width and low cross section relative to the nearby giant dipole resonance. The nearly 100 % linearly polarized monochromatic photon beam available at the High Intensity ?-ray Source (HI?S) provides a convenient method to study this collective state via Compton scattering. The interference of the E1 and E2 terms in the total elastic scattering amplitude provides enhanced sensitivity to the IVGQR parameters when measured simultaneously at forward and backward angles, significantly reducing the uncertainty in the extracted resonance parameters. We have performed such a measurement on ^89Y over a photon energy range of 23-35 MeV. Scattered photons were detected by the 8 element HIGS NaI Detector Array (HINDA) at polar angles of 55^o and 125^o, located in planes parallel and perpendicular to the plane of incident photon polarization. The out-of-plane to in-plane scattering ratio was measured as a function of beam energy at both polar angles, and the IVGQR parameters were determined from a least squares fit. Preliminary data will be presented along with the extracted resonance parameters for the IVGQR in ^89Y.

Sikora, Mark; Feldman, Gerald; Ahmed, Mohammad; Mueller, Jonathan; Myers, Luke; Weller, Henry; Zimmerman, William

2012-10-01

90

Polarized proton capture and the isovector giant quadrupole resonance in {sup 90}Zr  

SciTech Connect

Polarized proton capture experiments have been performed in an attempt to observe the Isovector Giant Quadrupole Resonance (IVGOR) in {sup 90}Zr. The cross section and vector analyzing power for transitions to the ground and low-lying states in the {sup 89}Y({tilde p}, {gamma}){sup 90}Zr reaction have been studied over the angular range over the energy range E{sub p} = 18.5-28.5 MeV (at {theta}{sub {gamma}} = 90{degrees}). A transition-matrix element analysis of the {gamma}{sub 0}E2 and E3 radiation, suggests a pure direct capture calculation predicts only 6% E2 strength. The A{sub y}(E) data at 90{degrees} for the {gamma}{sub 1+2+3} transitions (ie. to the first three strong single-particle excited states) depicts a resonance-like structure near ED = 23 MeV. These data are adequately described using the direct-semidirect (DSD) model by including IVGQ resonances at E{sub GQR} = 29.0 MeV built on each of the three states, with widths of E{sub GQR} = 5.5 MeV and strengths which exhaust 100% of the isovector E2 energy-weighted sum rule for each state. This same DSD calculation predicts a resonance structure in the {gamma}{sub 0} analyzing power near E{sub p} = 21 MeV, which is not seen in the data.

Godwin, M.A.; Feldman, G.; Hayward, E.; Kramer. L.H.; Weller, H.R. Dodge, W.R.

1993-10-01

91

Fluctuation properties of the strength function associated with the giant quadrupole resonance in {sup 208}Pb  

SciTech Connect

We performed fluctuation analysis by means of the local scaling dimension for the strength function of the isoscalar (IS) giant quadrupole resonance (GQR) in {sup 208}Pb where the strength function is obtained by the shell model calculation including 1p1h and 2p2h configurations. It is found that at almost all energy scales, fluctuation of the strength function obeys the Gaussian orthogonal ensemble (GOE) random matrix theory limit. This is contrasted with the results for the GQR in {sup 40}Ca, where at the intermediate energy scale of about 1.7 MeV, a deviation from the GOE limit was detected. It is found that the physical origin for this different behavior of the local scaling dimension is ascribed to the difference in the properties of the damping process.

Aiba, Hirokazu; Matsuo, Masayuki; Nishizaki, Shigeru; Suzuki, Toru [Kyoto Koka Women's College, 38 Kadono-cho Nishikyogoku, Ukyo-ku, 615-0882 Kyoto (Japan); Department of Physics, Faculty of Science, Niigata University, 950-2181 Niigata (Japan); Faculty of Humanities and Social Sciences, Iwate University, 3-18-34 Ueda, 020-8550 Morioka (Japan); Department of Physics, Tokyo Metropolitan University, 192-0397 Hachioji (Japan)

2011-02-15

92

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; agar, Veselko

2013-06-01

93

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

94

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

95

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

96

A Study of Transition-Metal Organometallic Complexes Combining (35) Cl Solid-State NMR Spectroscopy and (35) Cl?NQR Spectroscopy and First-Principles DFT Calculations.  

PubMed

A series of transition-metal organometallic complexes with commonly occurring metal?chlorine bonding motifs were characterized using (35) Cl solid-state NMR (SSNMR) spectroscopy, (35) Cl nuclear quadrupole resonance (NQR) spectroscopy, and first-principles density functional theory (DFT) calculations of NMR interaction tensors. Static (35) Cl ultra-wideline NMR spectra were acquired in a piecewise manner at standard (9.4?T) and high (21.1?T) magnetic field strengths using the WURST-QCPMG pulse sequence. The (35) Cl electric field gradient (EFG) and chemical shielding (CS) tensor parameters were readily extracted from analytical simulations of the spectra; in particular, the quadrupolar parameters are shown to be very sensitive to structural differences, and can easily differentiate between chlorine atoms in bridging and terminal bonding environments. (35) Cl?NQR spectra were acquired for many of the complexes, which aided in resolving structurally similar, yet crystallographically distinct and magnetically inequivalent chlorine sites, and with the interpretation and assignment of (35) Cl?SSNMR spectra. (35) Cl?EFG tensors obtained from first-principles DFT calculations are consistently in good agreement with experiment, highlighting the importance of using a combined approach of theoretical and experimental methods for structural characterization. Finally, a preliminary example of a (35) Cl?SSNMR spectrum of a transition-metal species (TiCl4 ) diluted and supported on non-porous silica is presented. The combination of (35) Cl?SSNMR and (35) Cl?NQR spectroscopy and DFT calculations is shown to be a promising and simple methodology for the characterization of all manner of chlorine-containing transition-metal complexes, in pure, impure bulk and supported forms. PMID:23907813

Johnston, Karen E; O'Keefe, Christopher A; Gauvin, Rgis M; Trbosc, Julien; Delevoye, Laurent; Amoureux, Jean-Paul; Popoff, Nicolas; Taoufik, Mostafa; Oudatchin, Konstantin; Schurko, Robert W

2013-08-01

97

Nuclear quadrupole resonance: a technique to control hydration processes in the pharmaceutical industry.  

PubMed

Pharmaceuticals can exist in many solid forms, which can have different physical and chemical properties. These solid forms include polymorphs, solvates, amorphous, and hydrates. Particularly, hydration process can be quite common since pharmaceutical solids can be in contact with water during manufacturing process and can also be exposed to water during storage. In the present work, it is proved that NQR technique is capable of detecting different hydrated forms not only in the pure raw material but also in the final product (tablets), being in this way a useful technique for quality control. This technique was also used to study the dehydration process from pentahydrate to trihydrate. PMID:21314133

Limandri, Silvina; Visovezky, Claudia; Prez, Silvina C; Schurrer, Clemar A; Wolfenson, Alberto E; Ferro, Maribel; Cuffini, Silvia L; de Souza, Joel Gonalves; Aguiar, F Armani; de Gaitani, C Masetto

2011-02-11

98

NMR and NQR study of the tetrahedral frustrated quantum spin system Cu2Te2O5Br2 in its paramagnetic phase  

NASA Astrophysics Data System (ADS)

The quantum antiferromagnet Cu2Te2O5Br2 was investigated by NMR and nuclear quadrupole resonance (NQR). The T125e NMR investigation showed that there is a magnetic transition around 10.5 K at 9 T, in agreement with previous studies. From the divergence of the spin-lattice relaxation rate, we ruled out the possibility that the transition could be governed by a one-dimensional divergence of the spin-spin correlation function. The observed anisotropy of the T125e shift was shown to be due to a spin polarization of the 5s2 E doublet of the [TeO3E] tetrahedra, highlighting the importance of tellurium in the exchange paths. In the paramagnetic state, Br NQR and NMR measurements led to the determination of the Br hyperfine coupling and the electric field gradient tensor, and to the spin polarization of Brp orbitals. The results demonstrate the crucial role of bromine in the interaction paths between Cu spins.

Comment, Arnaud; Mayaffre, Hadrien; Mitrovi?, Vesna; Horvati?, Mladen; Berthier, Claude; Grenier, Batrice; Millet, Patrice

2010-12-01

99

Measurement of in-situ stress in salt and rock using NQR techniques  

Microsoft Academic Search

A discussion of how stress and strain affect the quantities which can be measured in an NQR experiment shows that, for stresses of the magnitude to be expected at depths up to about 10,000 feet, quadrupole coupling constants will fall in the range of 1 to 10 kHz for both the sodium and chloride ions in NaCl. The most promising

E. Schempp; T. Hirschfeld; S. Klainer

1980-01-01

100

Thermochemical properties of aromatic radicals determined by Fouriertransform ion cyclotron resonance and flowing afterglow quadrupole-octopole-quadrupole mass spectrometry  

Microsoft Academic Search

Flowing Afterglow Guided-Ion Beam (FA-GIB) mass spectrometry allows the determination of a variety of thermochemical values for ionic and neutral molecules, including proton affinities, electron affinities, halide affinities, bond dissociation energies, and reaction threshold energies for endoergic ion-molecule reactions. Fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometry is another powerful mass spectrometry technique, one uniquely suited to kinetics studies of ion-molecule

John W Torchia

2005-01-01

101

Field test results of a nuclear quadrupole resonance land mine detection system  

NASA Astrophysics Data System (ADS)

We report on field test results conducted during 1999 in Bosnia and at the Army Mine Training School, Fort Leonard Wood, MO, on a ne prototype landmine detection system. In all test, non-metallic, anti-personnel (AP) and anti-tank (AT) landmines were detected via the NQR explosive signature with a probability of detection of 100 percent. The initial false alarm rate for the AP mine test was < 5 percent and was reduced to zero by a subsequent remeasurement. The test included typical burial depths and a variety of ground and weather conditions. In addition, the system can tolerate very high levels of metallic clutter and has repeatedly achieved zero false alarm rate when scanning for buried explosives at an EOD test range.

Hibbs, Andrew D.; Barrall, Geoffrey A.; Beevor, Simon; Burnett, Lowell J.; Derby, K.; Drew, A. J.; Gregory, Dave; Hawkins, C. S.; Huo, S.; Karunaratne, A.; Lathrop, Daniel K.; Lee, Young K.; Matthews, Robert; Milberger, Steve; Oehmen, B.; Petrov, T.; Skvoretz, David C.; Vierkoetter, S. A.; Walsh, David O.; Wu, Chin

2000-08-01

102

Statistical signal processing for detection of buried land mines using quadrupole resonance  

NASA Astrophysics Data System (ADS)

Quadrupole resonance (QR) is a technique that discriminates mines from clutter by exploiting unique properties of explosives, rather than the attributes of the mine that exist in many forms of anthropic clutter. After exciting the explosive with a properly designed electromagnetic-induction (EMI) system, one attempts to sense late-time spin echoes, which are characterized by radiation at particular frequencies. It is this narrow-band radiation that indicates the present of explosives, since this effect is not seen in most clutter, both natural and anthropic. However, explosives detection via QR is complicated by several practical issues. First, the late-time radiation is often very weak, particularly for TNT, and therefore the signal- to-noise ratio must be high for extracting the QR response. Further, the frequency at which the radiation occurs is often a strong function of the background environment, and therefore in practice the QR radiation frequency is not known a priori. Also, at frequencies of interest, there is a significant amount of background radiation, which induces radio frequency interference (RFI). In addition, the response properties of the system are sensitive to the height of the sensor above the ground, and the QR sensor effectively becomes 'de-tuned'. Finally, present QR systems cannot detect the explosive in metal-cased mines, thus the system and associated signal processing must be extended to also operate as a metal detector. Previously, we have shown that adaptive noise cancellation techniques, in particular, the least-mean-square algorithm, provide an effective means of RFI mitigation and can dramatically improve QR detection. In this paper we discuss several signal processing tools we have developed to further enhance the utility of QR explosives detection. In particular, with regard to the uncertainties concerning the background environment and sensor height, we explore statistical signal processing strategies to rigorously account for the inherent variability in these parameters.

Liu, Feng; Tantum, Stacy L.; Collins, Leslie M.; Carin, Lawrence

2000-08-01

103

Radio-frequency interference suppression for the quadrupole-resonance confirming sensor  

NASA Astrophysics Data System (ADS)

The quadrupole resonance (QR) technology can be used as a confirming sensor for buried plastic landmine detection by detecting the explosives (e.g., TNT and RDX) within the mine. We focus herein on the detection of TNT via the QR sensor. Since the frequency of the QR signal is located within the AM radio frequency band, the QR signal can be corrupted by strong radio frequency interferences (RFIs). Hence to detect the very weak QR signal, RFI mitigation is essential. Reference antennas, which receive RFIs only, can be used together with the main antenna, which receives both the QR signal and the RFIs, for RFI mitigation. By taking advantage of the spatial correlation of the RFIs received by the antenna array, the RFIs can be reduced significantly. However, the RFIs are usually colored both spatially and temporally and hence exploiting only the spatial diversity of the antenna array may not give the best performance. We exploit herein both the spatial and temporal correlation of the RFIs to improve the TNT detection performance. First, we consider exploiting the spatial correlation of the RFIs only and propose a maximum likelihood (ML) estimator for parameter estimation and a constant false alarm rate (CFAR) detector for TNT detection. Second, we adopt a multichannel autoregressive model to take into account the temporal correlation of the RFIs and devise a detector based on the model. Third, we take advantage of the temporal correlation by using a two-dimensional robust Capon beamformer (RCB) with the ML estimator for improved RFI mitigation. Finally, we combine the merits of all of the three aforementioned approaches for TNT detection. The effectiveness of the combined method is demonstrated using the experimental data collected by Quantum Magnetics, Inc.

Liu, Guoqing; Jiang, Yi; Li, Jian; Barrall, Geoffrey A.

2004-09-01

104

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 77K. 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

105

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

106

SQUID detected NMR and NQR. Superconducting Quantum Interference Device.  

PubMed

The dc Superconducting QUantum Interference Device (SQUID) is a sensitive detector of magnetic flux, with a typical flux noise of the order 1 muphi0 Hz(-1/2) at liquid helium temperatures. Here phi0 = h/2e is the flux quantum. In our NMR or NQR spectrometer, a niobium wire coil wrapped around the sample is coupled to a thin film superconducting coil deposited on the SQUID to form a flux transformer. With this untuned input circuit the SQUID measures the flux, rather than the rate of change of flux, and thus retains its high sensitivity down to arbitrarily low frequencies. This feature is exploited in a cw spectrometer that monitors the change in the static magnetization of a sample induced by radio frequency irradiation. Examples of this technique are the detection of NQR in 27Al in sapphire and 11B in boron nitride, and a level crossing technique to enhance the signal of 14N in peptides. Research is now focused on a SQUID-based spectrometer for pulsed NQR and NMR, which has a bandwidth of 0-5 MHz. This spectrometer is used with spin-echo techniques to measure the NQR longitudinal and transverse relaxation times of 14N in NH4ClO4, 63+/-6 ms and 22+/-2 ms, respectively. With the aid of two-frequency pulses to excite the 359 kHz and 714 kHz resonances in ruby simultaneously, it is possible to obtain a two-dimensional NQR spectrum. As a third example, the pulsed spectrometer is used to study NMR spectrum of 129Xe after polariza-tion with optically pumped Rb. The NMR line can be detected at frequencies as low as 200 Hz. At fields below about 2 mT the longitudinal relaxation time saturates at about 2000 s. Two recent experiments in other laboratories have extended these pulsed NMR techniques to higher temperatures and smaller samples. In the first, images were obtained of mineral oil floating on water at room temperature. In the second, a SQUID configured as a thin film gradiometer was used to detect NMR in a 50 microm particle of 195Pt at 6 mT and 4.2 K. PMID:9650797

Augustine, M P; TonThat, D M; Clarke, J

1998-03-01

107

First Measurement of the Giant Monopole and Quadrupole Resonances in a Short-Lived Nucleus: Ni56  

NASA Astrophysics Data System (ADS)

The isoscalar giant monopole resonance (GMR) and giant quadrupole resonance (GQR) have been measured in the Ni56 unstable nucleus by inducing the Ni56(d,d') reaction at 50AMeV in the Maya active target at the GANIL facility. The GMR and GQR centroids are measured at 19.30.5MeV and 16.20.5MeV, respectively. The corresponding angular distributions are extracted from 3 to 7. A multipole decomposition analysis using distorted wave Born approximation with random phase approximation transition densities shows that both the GMR and the GQR exhaust a large fraction of the energy-weighted sum rule. The demonstration of this new method opens a broad range of giant resonance studies at intermediate-energy radioactive beam facilities.

Monrozeau, C.; Khan, E.; Blumenfeld, Y.; Demonchy, C. E.; Mittig, W.; Roussel-Chomaz, P.; Beaumel, D.; Caamao, M.; Cortina-Gil, D.; Ebran, J. P.; Frascaria, N.; Garg, U.; Gelin, M.; Gillibert, A.; Gupta, D.; Keeley, N.; Marchal, F.; Obertelli, A.; Scarpaci, J.-A.

2008-02-01

108

First Measurement of the Giant Monopole and Quadrupole Resonances in a Short-Lived Nucleus: {sup 56}Ni  

SciTech Connect

The isoscalar giant monopole resonance (GMR) and giant quadrupole resonance (GQR) have been measured in the {sup 56}Ni unstable nucleus by inducing the {sup 56}Ni(d,d{sup '}) reaction at 50A MeV in the Maya active target at the GANIL facility. The GMR and GQR centroids are measured at 19.3{+-}0.5 MeV and 16.2{+-}0.5 MeV, respectively. The corresponding angular distributions are extracted from 3 deg. to 7 deg. A multipole decomposition analysis using distorted wave Born approximation with random phase approximation transition densities shows that both the GMR and the GQR exhaust a large fraction of the energy-weighted sum rule. The demonstration of this new method opens a broad range of giant resonance studies at intermediate-energy radioactive beam facilities.

Monrozeau, C.; Khan, E.; Blumenfeld, Y.; Beaumel, D.; Ebran, J. P.; Frascaria, N.; Gupta, D.; Marechal, F.; Scarpaci, J-A. [Institut de Physique Nucleaire IN2P3/CNRS, Universite Paris Sud, 91406 Orsay Cedex (France); Demonchy, C. E. [Department of Physics, Olivier Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Mittig, W.; Roussel-Chomaz, P.; Gelin, M. [GANIL, DSM/CEA, IN2P3/CNRS, BP 5027, 14076 Caen Cedex 5 (France); Caamano, M.; Cortina-Gil, D. [Universidad Santiago de Compostela, E-15706 Santiago de Compostela (Spain); Garg, U. [Physics Department, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Gillibert, A.; Keeley, N.; Obertelli, A. [CEA/DSM/DAPNIA/SPhN, Saclay, 91191 Gif-sur-Yvette Cedex (France)

2008-02-01

109

Sub parts-per-million mass measurement accuracy of intact proteins and product ions achieved using a dual electrospray ionization quadrupole fourier transform ion cyclotron resonance mass spectrometer  

Microsoft Academic Search

High mass measurement accuracy (MMA) is demonstrated for intact proteins and subsequent collision-induced dissociation product\\u000a ions using internal calibration. Internal calibration was accomplished using a dual electrospray ionization source coupled\\u000a with a hybrid quadrupole Fourier transform ion cyclotron resonance (Q-FT-ICR) mass spectrometer. Initially, analyte ions generated\\u000a via the first electrospray (ESI) emitter are isolated and dissociated in the external quadrupole.

D. Keith Williams Jr.; Adam M. Hawkridge; David C. Muddiman

2007-01-01

110

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

111

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

112

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(+)-HO(-) and NH-O) in the antiferroelectric phase. The two nitrogen positions become equivalent (NHO) 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; agar, Veselko; Asaji, Tetsuo; Gotoh, Kazuma; Ishida, Hiroyuki

2011-04-11

113

Local magnetic and structural properties of the low-temperature orthorhombic to low-temperature tetragonal transition: A 139La NQR study in lightly hole-doped La1.8-xEu0.2SrxCuO4  

Microsoft Academic Search

139La nuclear quadrupole resistance (NQR) and relaxation measurements in lightly hole-doped La1.8-xEu0.2SrxCuO4 have been used to investigate the microscopic properties of the low-temperature orthorhombic to low-temperature tetragonal transition. The transition is characterized by a sharp peak in 139La NQR relaxation rate, indicating phonon softening. We find that the structural phase transition is accompanied by a modification of the spin state.

B. J. Suh; P. C. Hammel; M. Hcker; B. Bchner

1999-01-01

114

Strong quadrupole interaction between the krypton 4p photoionization and 3d resonant excitation channels  

NASA Astrophysics Data System (ADS)

The angular distribution of Kr 4p photoelectrons was investigated experimentally in the photon energy range of the 3d-1 ? np resonant excitations. The experimental dipole and non-dipole anisotropy parameters were determined for the spin-orbit components of the Kr 4p shell. An interference effect was observed between the direct photoionization and the resonant excitation participator Auger decay processes in the photon energy dependence of the experimental anisotropy parameters.

Ricz, S.; Buhr, T.; Holste, K.; Borovik, A. A., Jr.; Bernhardt, D.; Schippers, S.; Kvr, .; Varga, D.; Mller, A.

2012-11-01

115

Charge order and low frequency spin dynamics in lanthanum cuprates revealed by Nuclear Magnetic Resonance  

NASA Astrophysics Data System (ADS)

We report detailed 17O, 139La, and 63,65Cu Nuclear Magnetic Resonance (NMR) and Nuclear Quadrupole Resonance (NQR) measurements in a stripe ordered La1.875Ba0.125CuO4 single crystal and in oriented powder samples of La1.8- x Eu0.2Sr x CuO4. We observe a partial wipeout of the 17O NMR intensity and a simultaneous drop of the 17O electric field gradient (EFG) at low temperatures where the spin stripe order sets in. In contrast, the 63,65Cu intensity is completely wiped out at the same temperature. The drop of the 17O quadrupole frequency is compatible with a charge stripe order. The 17O spin lattice relaxation rate shows a peak similar to that of the 139La, which is of magnetic origin. This peak is doping dependent and is maximal at x ? 1/8.

Grafe, H.-J.; Curro, N. J.; Young, B. L.; Vyalikh, A.; Vavilova, J.; Gu, G. D.; Hcker, M.; Bchner, B.

2010-10-01

116

Enhancement of mass resolution in the quadrupole ion trap via resonance ejection  

SciTech Connect

The Finnigan MAT ion trap mass spectrometer (ITMS) has unit mass resolution and a nominal upper mass/charge limit of only 650 when operated in the standard mass-selective instability method for acquiring mass spectra. Mass resolution up to {approx}2500 can be achieved with the use of the axial modulation technique. Ions can also be ejected at a q{sup z} value other than that corresponding to the mass-selective instability boundary by application of an auxiliary signal to the end-cap electrodes. When the frequency of this signal is resonant with the secular frequency for a particular m/z, such ions can become kinetically excited and ejected from the trap via a process known as resonance ejection. We demonstrate the capability to mass-selectively isolate or eject ions over a wide mass range and to generate mass spectra of electrospray-generated ions by scanning the frequency of the resonance ejection signal applied to the end-cap electrodes. A block diagram of the experimental modifications to the ITMS required for frequency-swept resonance ejection is shown. 2 refs., 5 figs.

Goeringer, D.E.; McLuckey, S.A.; Glish, G.L.

1991-01-01

117

Selective suppression and excitation of solid-state NMR resonances based on quadrupole coupling constants.  

PubMed

The dependence of the (Rotor Assisted Population Transfer) RAPT enhancement on offset frequency for nuclei experiencing different quadrupolar couplings has been exploited to design two new spectral editing schemes, pi/2-RAPT and RAPT-pi-RAPT, for the selective excitation or suppression, respectively, of nuclei with large quadrupolar couplings. Both approaches are demonstrated on the 87 Rb spectrum of Rb(2)SO(4), which contains two resonances with C(q) values of 2.6 and 5.3 MHz. The conditions for optimal selectivity are discussed. Combining pi/2-RAPT with the RIACT MQ-MAS experiment it is also demonstrated how a pure absorption mode triple quantum MQ-MAS spectrum devoid of narrow resonances can be obtained. PMID:12615150

Kwak, Hyung-Tae; Prasad, Subramanian; Clark, Ted; Grandinetti, Philip J

2003-02-01

118

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

119

Construction of a hybrid quadrupole\\/fourier transform ion cyclotron resonance mass spectrometer for versatile MS\\/MS above 10 kDa  

Microsoft Academic Search

Technological advancements including an open-cylindrical Penning trap with capacitively coupled ICR cell, selective ion accumulation\\u000a with a resolving quadrupole, and a voltage gradient used during ion extraction from an octopole ion trap, have individually\\u000a improved dynamic range and sensitivity in Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS). Documented\\u000a here is a new instrument utilizing these technologies toward the

Steven M. Patrie; Jay P. Charlebois; David Whipple; Neil L. Kelleher; Christopher L. Hendrickson; John P. Quinn; Alan G. Marshall; Biswarup Mukhopadhyay

2004-01-01

120

Secular dynamics of a coplanar, non-resonant planetary system under the general relativity and quadrupole moment perturbations  

NASA Astrophysics Data System (ADS)

We construct a secular theory of a coplanar system of N planets not involved in strong mean motion resonances, and which are far from collision zones. Besides the point-to-point Newtonian mutual interactions, we consider the general relativistic corrections to the gravitational potential of the star and the innermost planet, and also a modification of this potential by the quadrupole moment and tidal distortion of the star. We focus on hierarchical planetary systems. After averaging the model Hamiltonian with a simple algorithm making use of very basic properties of the Keplerian motion, we obtain analytical secular theory of high order in the semimajor axes ratio. A great precision of the analytic approximation is demonstrated with the numerical integrations of the equations of motion. A survey regarding model parameters (the masses, semimajor axes, spin rate of the star) reveals a rich and non-trivial dynamics of the secular system. Our study is focused on its equilibria. Such solutions predicted by the classic secular theory, which correspond to aligned (mode I) or anti-aligned (mode II) apsides, may be strongly affected by the gravitational corrections. The so-called true secular resonance, which is a new feature of the classic two-planet problem discovered by Michtchenko & Malhotra, may appear in other, different regions of the phase space of the generalized model. We found bifurcations of mode II from which emerge new, yet unknown in the literature, secularly unstable equilibria and a complex structure of the phase space. These equilibria may imply secularly unstable orbital configurations even for initially moderate eccentricities. The point mass gravity corrections can affect the long-term stability in the secular time-scale, which may directly depend on the age of the host star through its spin rate. We also analyse the secular dynamics of the ? Andromedae system in the realm of the generalized model. Also in this case of the three-planet system, new secular equilibria may appear.

Migaszewski, Cezary; Go?dziewski, Krzysztof

2009-01-01

121

Electron density distribution in cladribine (2-chloro-2?-deoxyadenosine) - A drug against leukemia and multiple sclerosis - Studied by multinuclear NQR spectroscopy and DFT calculations  

NASA Astrophysics Data System (ADS)

2-Chloro-2'-deoxyadenosine (Cladribine) chemotherapeutic drug has been studied experimentally in solid state by 35Cl NQR and NMR-NQR double resonance and theoretically by the Density Functional Theory. Fifteen resonance frequencies on 14N have been detected and assigned to particular nitrogen sites in the 2-CdA molecule. The effects of tautomerism, regioisomerism, conformations and molecular aggregations, related to intermolecular hydrogen bond formation, on the NQR parameters have been analysed within the DFT and AIM ( Atoms in Molecules) formalism. The properties of the whole molecule, the so-called global reactivity descriptors, have been calculated for a comparison of both syn and anti conformations of 2-CdA molecule to check the effect of crystal packing on molecular conformation.

Latosi?ska, J. N.; Latosi?ska, M.; Seliger, J.; agar, V.; Kazimierczuk, Z.

2009-07-01

122

Zero field NMR and NQR  

SciTech Connect

Methods are described and demonstrated for detecting the coherent evolution of nuclear spin observables in zero magnetic field with the full sensitivity of high field NMR. The principle motivation is to provide a means of obtaining solid state spectra of the magnetic dipole and electric quadrupole interactions of disordered systems without the line broadening associated with random orientation with respect to the applied magnetic field. Comparison is made to previous frequency domain and high field methods. A general density operator formalism is given for the experiments where the evolution period is initiated by a sudden switching to zero field and is terminated by a sudden restoration of the field. Analytical expressions for the signals are given for a variety of simple dipolar and quadrupolar systems and numerical simulations are reported for up to six coupled spin-1/2 nuclei. Experimental results are reported or reviewed for /sup 1/H, /sup 2/D, /sup 7/Li, /sup 13/C, and /sup 27/Al nuclei in a variety of polycrystalline materials. The effects of molecular motion and bodily sample rotation are described. Various extensions of the method are discussed, including demagnetized initial conditions and correlation by two-dimensional Fourier transformation of zero field spectra with themselves or with high field spectra.

Zax, D.B.; Bielecki, A.; Zilm, K.W.; Pines, A.; Weitekamp, D.P.

1985-11-15

123

Measurement of Electric Quadrupole Moments for 31Al Using Spin Polarized RI Beams  

SciTech Connect

The electromagnetic moment is a sensitive probe to investigate microscopic structure. In order to measure the electromagnetic moment, {beta}-NMR and {beta}-NQR methods are employed taking advantage of the fragment spin polarization produced by the fragmentation reaction. The measurement of the electric quadrupole moment for ground-state 31Al has been been carried out by {beta}-NQR method. Spin-polarized 31Al nuclei were obtained from the fragmentation of 40Ar projectiles, and were implanted in {alpha}-Al2O3 stopper. The electric quadrupole moment was deduced from the measured quadrupole coupling constant. The obtained value is |Q(31Al)| 104(9) e{center_dot}mb.

Nagae, D.; Asahi, K.; Takemura, M.; Takase, K.; Uchida, M.; Shimada, K.; Arai, T.; Inoue, T.; Kagami, S.; Hatakeyama, N. [Department of Physics, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8551 (Japan); Ueno, H.; Kameda, D.; Yoshimi, A.; Sugimoto, T.; Nagatomo, T.; Kobayashi, Y. [RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198 (Japan)

2007-06-13

124

Radio-frequency tunable atomic magnetometer for detection of solid-state NQR  

NASA Astrophysics Data System (ADS)

We constructed a potassium atomic magnetometer which resonantly detects rf magnetic fields with subfemtotesla sensitivity. The resonance frequency is set by the Zeeman resonance of the potassium atoms in a static magnetic field applied to the magnetometer cell. Strong optical pumping of the potassium atoms into a stretched state reduces spin-exchange broadening of the Zeeman resonance, resulting in relatively small linewidth of about 200 Hz (half-width at half-maximum). The magnetometer was used to detect ^14N NQR signal from powdered ammonium nitrate at 423 kHz, with sensitivity an order of magnitude higher than with a conventional room temperature pickup coil with comparable geometry. The demonstrated sensitivity of 0.24 fT/Hz^1/2 can be improved by several means, including use of higher power lasers for pumping and probing. Our technique can potentially be used to develop a mobile, open-access NQR spectrometer for detection of nitrogen-containing solids of interest in security applications.

Lee, S.-K.; Sauer, K. L.; Seltzer, S. J.; Alem, O.; Romalis, M. V.

2007-06-01

125

First-principles study of (75)As NQR in arsenic-chalcogenide compounds.  

PubMed

We present a theoretical study of the nuclear quadrupole interaction, ?(Q), of (75)As in crystalline and amorphous materials containing sulfur and selenium, and compare them with experiment. We studied a combination of hydrogen-terminated molecular clusters and periodic cells at various levels of quantum chemical theory. The results show clearly that the standard density functional theory (DFT) approximations, LDA and GGA, underestimate the nuclear quadrupole (NQR) interaction systematically, while Hartree-Fock theory overestimates it to an even greater degree. However, various levels of configuration interaction and the B3LYP hybrid exchange-correlation functional, which includes some exact exchange, give very good quantitative agreement for As bonded only to the chalcogen species. As-As bonds require highly converged basis sets. We have performed a systematic study of the effect of local distortions around an arsenic atom on ?(Q) and ?. Using a simple, semiclassical model, we have combined our total energy results with our NQR calculations to predict ?(Q) lineshapes for bond angle and bond length distortions. Our predictions for lineshape, including first and second moments, are in excellent agreement with the results of Su et al for a-As(2)S(3), a-As(2)Se(3) and a-AsSe. We offer new insight into the distortions that led to this inhomogeneous broadening. Our results show clearly that, for trivalent arsenic atoms with zero or one arsenic nearest neighbor, symmetric bond stretching is the predominant contributor to the ?(Q) linewidth. However, in the presence of two arsenic nearest neighbors, distortions of the As-As-As apex angle dominates and, in fact, leads to a much larger second moment, in agreement with experiment. PMID:21406910

Edwards, Arthur H; Taylor, P C; Campbell, Kristy A; Pineda, Andrew C

2011-01-19

126

Site-directed mutagenesis of conserved cysteine residues in NqrD and NqrE subunits of Na+-translocating NADH:quinone oxidoreductase.  

PubMed

Each of two hydrophobic subunits of Na+-translocating NADH:quinone oxidoreductase (NQR), NqrD and NqrE, contain a pair of strictly conserved cysteine residues within their transmembrane alpha-helices. Site-directed mutagenesis showed that substitutions of these residues in NQR of Vibrio harveyi blocked the Na+-dependent and 2-n-heptyl-4-hydroxyquinoline N-oxide-sensitive quinone reductase activity of the enzyme. However, these mutations did not affect the interaction of NQR with NADH and menadione. It was demonstrated that these conserved cysteine residues are necessary for the correct folding and/or the stability of the NQR complex. Mass and EPR spectroscopy showed that NQR from V. harveyi bears only a 2Fe-2S cluster as a metal-containing prosthetic group. PMID:18298367

Fadeeva, M S; Bertsova, Y V; Verkhovsky, M I; Bogachev, A V

2008-02-01

127

I: Low Frequency NMR and NQR Using a dc SQUID. II: Variable-temperature 13C CP/MAS of Organometallics  

SciTech Connect

NMR and NQR at low frequencies are difficult prospects due to small nuclear spin polarization. Furthermore, the sensitivity'of the inductive pickup circuitry of standard spectrometers is reduced as the frequency is lowered. I have used a cw-SQUID (Superconducting QUantum Interference Device) spectrometer, which has no such frequency dependence, to study the local atomic environment of {sup 14}N via the quadrupolar interaction. Because {sup 14}N has spin I = 1 and a 0-6 MHz frequency range, it is not possible to obtain well-resolved spectra in high magnetic fields. I have used a technique to observe {sup 14}N NQR resonances via their effect on neighboring protons mediated by the heteronuclear dipolar interaction to study peptides and narcotics. The sensitivity of the SQUID is not enough to measure low-frequency surface (or other low spin density) systems. The application of spin-polarized xenon has been previously used to enhance polarization in conventional NMR experiments. Because xenon only polarizes spins with which it is in contact, it is surface selective. While differences in chemical shifts between surface and bulk spins are not large, it is expected that the differences in quadrupole coupling constant should be very large due to the drastic change of the electric field gradient surrounding spins at the surface. With this in mind, I have taken preliminary steps to measure SQUID detected polarization transfer from Xe to another spin species at 4.2 K and in small magnetic fields (<50 G). In this regime, the spin-lattice relaxation of xenon is dependent on the applied magnetic field. The results of our efforts to characterize the relaxation of xenon are presented. The final section describes the solid-state variable-temperature (VT) one- and two-dimensional {sup 13}C cross polarization (CP)/magic angle spinning (MAS) NMR of Hf({eta}{sup 5}-C{sub 5}H{sub 5}){sub 2}({eta}{sup 1}-C{sub 5}H{sub 5}){sub 2}, Zr({eta}{sup 5}-C{sub 5}H{sub 5}){sub 3}({eta}{sup 1}-C{sub 5}H{sub 5}) and Sn({eta}{sup 1}-C{sub 5}H{sub 5}){sub 4}. This work was undertaken in the hope of gaining insight into the intramolecuhrr dynamics, specifically which fluxional processes exist in the solid state, by what mechanism rearrangements are occurring, and the activation energies by which these processes are governed.

Ziegeweid, M.A.

1995-11-29

128

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

129

Local magnetic and structural properties of the low-temperature orthorhombic to low-temperature tetragonal transition: A ¹³⁹La NQR study in lightly hole-doped La{sub 1.8-x}Eu{sub 0.2}SrCuO  

Microsoft Academic Search

¹³⁹La nuclear quadrupole resistance (NQR) and relaxation measurements in lightly hole-doped La{sub 1.8-x}Eu{sub 0.2}SrCuO have been used to investigate the microscopic properties of the low-temperature orthorhombic to low-temperature tetragonal transition. The transition is characterized by a sharp peak in ¹³⁹La NQR relaxation rate, indicating phonon softening. We find that the structural phase transition is accompanied by a modification of the

B. J. Suh; P. C. Hammel; M. Huecker; B. Buechner

1999-01-01

130

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

131

Nuclear magnetic resonance with dc SQUID (Super-conducting QUantum Interference Device) preamplifiers  

SciTech Connect

Sensitive radio-frequency (rf) amplifiers based on dc Superconducting QUantum Interface Devices (SQUIDS) are available for frequencies up to 200 MHz. At 4.2 K, the gain and noise temperature of a typical tuned amplifier are 18.6 +- 0.5 dB and 1.7 +- 0.5 K at 93 MHz. These amplifiers are being applied to a series of novel experiments on nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR). The high sensitivity of these amplifiers was demonstrated in the observation of ''nuclear spin noise'', the emission of photons by /sup 35/Cl nuclei in a state of zero polarization. In the more conventional experiments in which one applies a large rf pulse to the spins, a Q-spoiler, consisting of a series array of Josephson junctions, is used to reduce the Q of the input circuit to a very low value during the pulse. The Q-spoiler enables the circuit to recover quickly after the pulse, and has been used in an NQR experiment to achieve a sensitivity of about 2 /times/ 10/sup 16/ nuclear Bohr magnetons in a single free precession signal with a bandwidth of 10 kHz. In a third experiment, a sample containing /sup 35/Cl nuclei was placed in a capacitor and the signal detected electrically using a tuned SQUID amplifier and Q-spoiler. In this way, the electrical polarization induced by the precessing Cl nuclear quadrupole moments was detected: this is the inverse of the Stark effect in NQR. Two experiments involving NMR have been carried out. In the first, the 30 MHz resonance in /sup 119/Sn nuclei is detected with a tuned amplifier and Q-spoiler, and a single pulse resolution of 10/sup 18/ nuclear Bohr magnetons in a bandwidth of 25 kHz has been achieved. For the second, a low frequency NMR system has been developed that uses an untuned input circuit coupled to the SQUID. The resonance in /sup 195/Pt nuclei has been observed at 55 kHz in a field of 60 gauss. 23 refs., 11 figs.

Fan, N.Q.; Heaney, M.B.; Clark, J.; Newitt, D.; Wald, L.; Hahn, E.L.; Bierlecki, A.; Pines, A.

1988-08-01

132

Quantum tunneling effects in dipolar ferroelectrics: A nuclear-quadrupole-resonance study in HCl-DCl mixed crystals  

Microsoft Academic Search

Static and dynamical effects from a quantum tunneling contribution to the dipole reorientations in the ferroelectric phases of the mixed crystals HCl-DCl have been studied through 35Cl nuclearquadrupole-resonance pulse Fourier-transform measurements. Experimental data for the transition temperatures Tc and the local correlation times tau, of both the HCl and DCl dipoles, for several percentages of deuteration are analyzed in the

M. Crowley; J. Brookeman; A. Rigamonti

1983-01-01

133

The single NqrB and NqrC subunits in the Na(+)-translocating NADH: quinone oxidoreductase (Na(+)-NQR) from Vibrio cholerae each carry one covalently attached FMN.  

PubMed

The Na(+)-translocating NADH:quinone oxidoreductase (Na(+)-NQR) is the prototype of a novel class of flavoproteins carrying a riboflavin phosphate bound to serine or threonine by a phosphodiester bond to the ribityl side chain. This membrane-bound, respiratory complex also contains one non-covalently bound FAD, one non-covalently bound riboflavin, ubiquinone-8 and a [2Fe-2S] cluster. Here, we report the quantitative analysis of the full set of flavin cofactors in the Na(+)-NQR and characterize the mode of linkage of the riboflavin phosphate to the membrane-bound NqrB and NqrC subunits. Release of the flavin by ?-elimination and analysis of the cofactor demonstrates that the phosphate group is attached at the 5'-position of the ribityl as in authentic FMN and that the Na(+)-NQR contains approximately 1.7mol covalently bound FMN per mol non-covalently bound FAD. Therefore, each of the single NqrB and NqrC subunits in the Na(+)-NQR carries a single FMN. Elimination of the phosphodiester bond yields a dehydro-2-aminobutyrate residue, which is modified with ?-mercaptoethanol by Michael addition. Proteolytic digestion followed by mass determination of peptide fragments reveals exclusive modification of threonine residues, which carry FMN in the native enzyme. The described reactions allow quantification and localization of the covalently attached FMNs in the Na(+)-NQR and in related proteins belonging to the Rhodobacter nitrogen fixation (RNF) family of enzymes. This article is part of a Special Issue entitled: 17th European Bioenergetics Conference (EBEC 2012). PMID:22366169

Casutt, Marco S; Schlosser, Andreas; Buckel, Wolfgang; Steuber, Julia

2012-02-16

134

NQR spin-echo methods at very low temperatures  

NASA Astrophysics Data System (ADS)

Pulsed methods may be successfully used in very low temperature NMR or NQR experiments provided good thermal anchoring of the sample is achieved. In order to reduce heating effects, it is advantageous to use rf pulses that are shorter than the standard magnetization tipping pulses used at higher temperatures. The present work describes the use of short nonstandard rf pulses in NQR spin-echo experiments on powdered samples. Theoretical density matrix calculations have been carried out, and the resulting expression for the echo amplitude confirmed by experiment. Measurements were made on a powder sample of high-purity semimetallic arsenic using a sample probe designed for use in a dilution refrigerator. Preliminary spin-lattice relaxation-time measurements show that the Korringa relation holds in arsenic down to 150 mK.

Goudemond, I. P.; Keartland, J. M.; Hoch, M. J. R.

1991-03-01

135

Electric quadrupole contribution to resonant x-ray scattering: Application to multipole ordering phases in Ce1-xLaxB6  

NASA Astrophysics Data System (ADS)

We study the electric quadrupole (E2) contribution to resonant x-ray scattering (RXS). Under the assumption that the rotational invariance is preserved in the Hamiltonian describing the intermediate state of scattering, we derive a useful expression for the RXS amplitude. One of the advantages the derived expression possesses is the full information of the energy dependence, lacking in all the previous studies using the fast collision approximation. The expression is also helpful to classify the spectra into multipole order parameters which are brought about. The expression is suitable to investigate the RXS spectra in the localized f electron systems. We demonstrate the usefulness of the formula by calculating the RXS spectra at the CeL2,3 edges in Ce1-xLaxB6 on the basis of the formula. We obtain the spectra as a function of energy in agreement with the experiment of Ce0.7La0.3B6 . Analyzing the azimuthal angle dependence, we find the sixfold symmetry in the ?-?' channel and the threefold one in the ?-?' channel not only in the antiferro-octupole (AFO) ordering phase but also in the antiferroquadrupole (AFQ) ordering phase, which behavior depends strongly on the domain distribution. The sixfold symmetry in the AFQ phase arises from the simultaneously induced hexadecapole order. Although the AFO order is plausible for phase IV in Ce1-xLaxB6 , the possibility of the AFQ order may not be ruled out on the basis of azimuthal angle dependence alone.

Nagao, Tatsuya; Igarashi, Jun-Ichi

2006-09-01

136

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

137

NQR investigation of pressure-induced charge transfer in oxygen-deficient YBa sub 2 Cu sub 3 O sub 7-. delta. (. delta. = 0. 38)  

SciTech Connect

Measurements of the pressure dependence of {sup 63}Cu nuclear quadrupole frequency in YBa{sub 2}Cu{sub 3}O{sub 6.62} from ambient pressure up to 1.5 GPa at 4k have been performed. {Tc} was found to increase with pressure: d{Tc}/dp {approximately} 5 K/GPa. All observed NQR lines are linear in pressure: dln{nu}{sub Q}/dp=z. We found positive z for the empty chain sites, consistent with ionic (Cu{sup 1+}) configuration in which the atom simply feels a squeezing lattice. Planar coppers close to the empty chains have positive z, while those that are close to full chains have z {approximately} 0. We present an analysis of the NQR result on the basis of the charge transfer model in which the mobile charges migrate from the chain to the plane sites. We deduced that a transfer of 0.021 holes to the O(2,3) sites would explain the result in YBa{sub 2}Cu{sub 3}O{sub 6.62}, whereas only 0.007 holes transfer in fully oxygenated YBa{sub 2}Cu{sub 3}O{sub 7}.

Reyes, A.P.; Ahrens, E.T.; Hammel, P.C.; Heffner, R.H. (Los Alamos National Lab., NM (United States)); Takigawa, M. (International Business Machines Corp., Yorktown Heights, NY (United States). Thomas J. Watson Research Center)

1992-01-01

138

NMR and NQR study of the electronic and structural properties of Al-Cu-Fe and Al-Cu-Ru quasicrystals  

SciTech Connect

[sup 27]Al and [sup 63,65]Cu NMR is reported for powdered stable Al-Cu-Fe and Al-Cu-Ru icosahedral quasicrystals and crystalline approximants, and for an Al-Pd-Mn single-grain quasicrystal. [sup 27]Al NQR spectra at 4.2 K were observed in Al-Cu-Fe and Al-Cu-Ru samples. From quadrupole-perturbed NMR spectra at different magnetic fields, and from zero-field NQR spectra, a wide distribution of local electric-field gradient (EFG) tensor components and principal-axis-system orientations was found at the Al site. A model EFG calculation based on a 1/1 Al-Cu-Fe approximant successfully explained the observed NQR spectra. The average local gradient is largely determined by the [ital p]-electron wave function at the Al site, while the width of the distribution is due to EFG lattice contribution. Comparison of [sup 63]Cu and [sup 27]Al NMR shows the EFG distribution at the two sites is similar, but the electronic contribution to the EFG is considerably smaller at the Cu site, in agreement with a more [ital s]-type wave function of the conduction electrons. Overall spread of EFG values is well reproduced by calculation based on the approximant. However, the experimental spectra indicate a much larger number of nonequivalent sites when compared with the simulated NQR spectra based on the 1/1 approximant. The short-range, local chemical order is well represented by the approximant, but differences in coordination must be included at intermediate range in the quasicrystal. Measured [sup 27]Al Knight shift, magnetic susceptibility, and nuclear spin-lattice relaxation time as a function of temperature indicate reduced density of states at the Fermi level by a factor of 7 or 8 from the value in Al metal, consistent with the notion of a pseudogap for these quasicrystals. No differences in measured parameters were detected as a function of composition of the quasicrystalline alloys.

Shastri, A.; Borsa, F.; Torgeson, D.R.; Shield, J.E.; Goldman, A.I. (Ames Laboratory, U.S. Department of Energy and Department of Physics Astronomy, Iowa State University, Ames, Iowa 50011 (United States))

1994-12-01

139

Determination of the Parameters of the Electric Field Gradient Tensor for Nuclei with Half Integral Spin from Zeeman-Split NQR Spectra  

Microsoft Academic Search

A new method is proposed for determining the magnitude of the coupling constant, the asymmetry parameter and the orientation of the principal axes of the electric field gradient tensor at the site of a quadrupole nucleus with half integral spin. A function is constructed from the first order splitting of the nuclear quadrupole resonance absorption line produced by a small

S. Sengupta; R. Roy; A. K. Saha

1972-01-01

140

Antiferromagnetic properties of a water-vapor-inserted YBa2 Cu3 O6.5 compound studied byNMR, NQR, and ?SR  

NASA Astrophysics Data System (ADS)

We present a detailed NQR, nuclear magnetic resonance (NMR), and ?SR study of the magnetic phase obtained during a topotactic chemical reaction of YBa2Cu3O6.5 high-temperature superconductor with low-pressure water vapor. Cu65 -enriched samples have been used for NQR/NMR studies which allows to get a good resolution in the Cu(1) NQR and Cu(2) zero field NMR (ZFNMR) spectra. It is shown that the NQR spectrum of the starting material transforms progressively under insertion of water, and almost completely disappears when about one H2O molecule is inserted per unit cell. Similarly, a Cu65 ZFNMR signal characteristic of this water inserted material appears and grows with increasing water content, which indicates that the products of the reaction are nonsuperconducting antiferromagnetic phases in which the copper electronic magnetic moments in the CuO2 bilayers are ordered. The use of Cu65 -enriched samples allowed us to reliably resolve three different copper resonances which correspond to different internal magnetic fields. The antiferromagnetic phases are also felt by proton NMR which reveals two sites with static internal fields of 150 and about 15 Gauss, respectively. ?SR studies performed on a series of samples prepared in the same way as the C65u -enriched ones reveal two muon sites with the same local fields as the proton sites, which vanish at T?400K . This indicates that muons preferentially occupy proton vacancy sites, and that the magnetic phases have similar Nel temperatures as the other bilayer undoped cuprate compounds. An analysis of the internal fields on the different spin probes suggests that they can be all assigned to a single magnetic phase at large water content in which the Cu(1) electron spins order with those of the Cu(2) . The detailed evolution of the spectra with the progressive increase of water content is shown to be compatible with a coexistence of phases during the early stages ot the reaction. It appears that even samples packed in paraffin underwent a transformation of a substantial part of the sample after 6 years storage in atmosphere. Samples packed in Stycast epoxy resin heated moderately to a temperature (200C) undergo a reaction with epoxy decomposition products which yield the formation of the same final compound. It is clear that such effects should be considered quite seriously and avoided in experiments attempting to resolve tiny effects in these materials, such as those performed in some recent neutron scattering experiments.

Dooglav, A. V.; Egorov, A. V.; Mukhamedshin, I. R.; Savinkov, A. V.; Alloul, H.; Bobroff, J.; Macfarlane, W. A.; Mendels, P.; Collin, G.; Blanchard, N.; Picard, P. G.; King, P. J. C.; Lord, J.

2004-08-01

141

Oxidant-induced formation of a neutral flavosemiquinone in the Na+-translocating NADH:Quinone oxidoreductase (Na+-NQR) from Vibrio cholerae.  

PubMed

The Na(+)-translocating NADH:quinone oxidoreductase (Na(+)-NQR) from the human pathogen Vibrio cholerae is a respiratory flavo-FeS complex composed of the six subunits NqrA-F. The Na(+)-NQR was produced as His(6)-tagged protein by homologous expression in V. cholerae. The isolated complex contained near-stoichiometric amounts of non-covalently bound FAD (0.78 mol/mol Na(+)-NQR) and riboflavin (0.70 mol/mol Na(+)-NQR), catalyzed NADH-driven Na(+) transport (40 nmol Na(+)min(-1) mg(-1)), and was inhibited by 2-n-heptyl-4-hydroxyquinoline-N-oxide. EPR spectroscopy showed that Na(+)-NQR as isolated contained very low amounts of a neutral flavosemiquinone (10(-3) mol/mol Na(+)-NQR). Reduction with NADH resulted in the formation of an anionic flavosemiquinone (0.10 mol/mol Na(+)-NQR). Subsequent oxidation of the Na(+)-NQR with ubiquinone-1 or O(2) led to the formation of a neutral flavosemiquinone (0.24 mol/mol Na(+)-NQR). We propose that the Na(+)-NQR is fully oxidized in its resting state, and discuss putative schemes of NADH-triggered redox transitions. PMID:18454933

Tao, Minli; Casutt, Marco S; Fritz, Gnter; Steuber, Julia

2008-04-11

142

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

143

NQR investigation of pressure-induced charge transfer in oxygen-deficient YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} ({delta} = 0.38)  

SciTech Connect

Measurements of the pressure dependence of {sup 63}Cu nuclear quadrupole frequency in YBa{sub 2}Cu{sub 3}O{sub 6.62} from ambient pressure up to 1.5 GPa at 4k have been performed. {Tc} was found to increase with pressure: d{Tc}/dp {approximately} 5 K/GPa. All observed NQR lines are linear in pressure: dln{nu}{sub Q}/dp=z. We found positive z for the empty chain sites, consistent with ionic (Cu{sup 1+}) configuration in which the atom simply feels a squeezing lattice. Planar coppers close to the empty chains have positive z, while those that are close to full chains have z {approximately} 0. We present an analysis of the NQR result on the basis of the charge transfer model in which the mobile charges migrate from the chain to the plane sites. We deduced that a transfer of 0.021 holes to the O(2,3) sites would explain the result in YBa{sub 2}Cu{sub 3}O{sub 6.62}, whereas only 0.007 holes transfer in fully oxygenated YBa{sub 2}Cu{sub 3}O{sub 7}.

Reyes, A.P.; Ahrens, E.T.; Hammel, P.C.; Heffner, R.H. [Los Alamos National Lab., NM (United States); Takigawa, M. [International Business Machines Corp., Yorktown Heights, NY (United States). Thomas J. Watson Research Center

1992-03-01

144

Quadrupole coupling constants and isomeric Mssbauer 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

145

Study of local magnetic fields in the oxide ?-Bi 2 O 3 by NQR and ? SR techniques  

Microsoft Academic Search

NQR and?SR investigations of the local magnetic field in?-Bi2O3 were performed. In theNQR experiments on?-Bi2O3 which is usually considered as diamagnetic, the splitting of the spectral lines revealed a local field on the bismuth nuclei. The internal magnetic field obtained by?SR significantly exceeds the dipole field from Bi nuclear magnetic moments. A possible source of the local magnetic fields is

V. N. Duginov; V. G. Grebinnik; T. N. Mamedov; V. G. Olshevsky; V. Yu. Pomjakushin; V. A. Zhukov; B. F. Kirillov; B. A. Nikolsky; V. G. Orlov; A. V. Pirogov; A. N. Ponomarev; V. A. Suetin; E. A. Kravchenko

1994-01-01

146

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

147

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

148

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 23 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

149

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

150

Resonance  

NSDL National Science Digital Library

For advanced undergraduate students: Observe resonance in a collection of driven, damped harmonic oscillators. Vary the driving frequency and amplitude, the damping constant, and the mass and spring constant of each resonator. Notice the long-lived transients when damping is small, and observe the phase change for resonators above and below resonance.

Simulations, Phet I.; Dubson, Michael; Loeblein, Patricia; Olson, Jonathan; Perkins, Kathy; Gratny, Mindy

2011-07-20

151

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 OH???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

152

Basic aspects and main results of NMR-NQR spectroscopies in high-temperature superconductors  

NASA Astrophysics Data System (ADS)

After a mention of the structural, magnetic and electronic properties of high-temperature superconductors (HTSC), the basic principles of NMR-NQR experiments in these compounds are presented, emphasizing the marked differences and the novel aspects of the latter systems in comparison with metals and conventional superconductors. It follows a review of NMR-NQR spectra and relaxation rates in two-dimensional quantum antiferromagnets (particularly 0034-4885/61/10/002/img1) driven towards the superconducting state by charge doping. The main results obtained in the normal state of HTSC are summarized, while the problems of the spin-gap and of the superconducting fluctuations are discussed to a certain extent, by including the most recent contributions. An overview is given on the main conclusions derived from NMR-NQR experiments in the superconducting state. A section is devoted to the insights into the vortex lattice and the flux lines motion that have been obtained from NMR line narrowing, 0034-4885/61/10/002/img2 and echo dephasing. This review deals mostly with three systems, 0034-4885/61/10/002/img3, 0034-4885/61/10/002/img4 and 0034-4885/61/10/002/img5.

Rigamonti, A.; Borsa, F.; Carretta, P.

1998-10-01

153

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

154

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

155

63,65Cu NQR study of Zn and Ni doped YBa 2Cu 3O 7  

Microsoft Academic Search

63,65Cu NQR measurements have been performed on Zn and Ni doped YBCO (YBa2Cu3?xMxO7, M?Zn or Ni, x=0.0 ? 0.09). Distinctive differences due to the nonmagnetic Zn and the magnetic Ni dopants substituted for copper are compared microscopically based on the plane and the chain 63,65Cu NQR data. Both spin-lattice and spin-spin relaxation rates decrease for Zn doped YBCO whereas they

K. S. Han; B. J. Mean; K. H. Lee; D. H. Kim; S. W. Seo; Moohee Lee; W. C. Lee; J. S. Cho

2000-01-01

156

Versatile Magnetic Resonance Spectrometer  

Microsoft Academic Search

A Pound-Knight-Watkins marginal oscillator has been modified by the addition of a vibrating capacitor in parallel with the tuning capacitor to produce a simple circuit which may be used to observe paramagnetic resonance at low fields, nuclear magnetic resonance, and nuclear quadrupole resonance. Suggestions are made as to the type of information which may be obtained in an undergraduate laboratory

J. A. Cowen; W. H. Tanttila

1958-01-01

157

VERSATILE MAGNETIC RESONANCE SPECTROMETER  

Microsoft Academic Search

A Pound-Knight-Watkins marginal osciliator was modified by the addition ; of a vibrating capacitor in parallel with the tuning capacitor to produce a ; simple circuit which may be used to observe paramagnetic resonance at low fields, ; nuclear magnetic resonance, and nuclear quadrupole resonance. Suggestions are ; mnde as to the type of information which may be obtained in

J. A. Cowen; W. H. Tanttila

1958-01-01

158

Resonance  

NSDL National Science Digital Library

All About Circuits is a website that âprovides a series of online textbooks covering electricity and electronics.â Written by Tony R. Kuphaldt, the textbooks available here are wonderful resources for students, teachers, and anyone who is interested in learning more about electronics. This specific section, Resonance, is the sixth chapter in the Volume II textbook. Topics covered in this chapter include: electric pendulum, simple parallel resonance, simple series resonance, resonance in series-parallel circuits, and Q and bandwidth of a resonant circuit. Diagrams and detailed descriptions of concepts are included throughout the chapter to provide users with a comprehensive lesson. Visitors to the site are also encouraged to discuss concepts and topics using the All About Circuits discussion forums (registration with the site is required to post materials).

Kuphaldt, Tony R.

2008-07-07

159

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

160

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

161

209Bi NMR and NQR investigation of the small-gap semiconductor Ce3Bi4Pt3  

Microsoft Academic Search

We report measurements of the temperature dependence of the 209Bi nuclear quadrupole resonance frequency nuQ, the Knight shift K, and the spin-lattice relaxation rate 1\\/T1 in the small-gap semiconductor Ce3Bi4Pt3 between 1.8 and 300 K. Corresponding measurements also are reported for the nonmagnetic metallic isomorph La3Bi4Pt3. The nuQ data in the Ce compound show a characteristic departure from metallic-to-insulating behavior

A. P. Reyes; R. H. Heffner; P. C. Canfield; J. D. Thompson; Z. Fisk

1994-01-01

162

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

163

Quadrupole coupling constants and isomeric Mssbauer 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

164

Spatial electron density distribution of the chlorine atoms in organic and complex compounds as studied by NQR and MNDO  

Microsoft Academic Search

Quantitative correlation of the NQR frequencies and asymmetry parameters of the EFG at nuclei having spin I = 32 with the population of the indicator atom (at Npx = 2) and nonaxiality of its electron distribution has been obtained. The Npy and Npz populations of the Cl atoms in some chloro-containing organic and coordination compounds have been calculated using the

V. P. Feshin; M. Yu. Konshin

1995-01-01

165

Study of local magnetic fields in the oxide alpha-Bi2O3 by NQR and muSR techniques  

Microsoft Academic Search

NQR and muSR investigations of the local magnetic field in alpha-Bi2O3 were performed. In the NQR experiments on alpha-Bi2O3 which is usually considered as diamagnetic, the splitting of the spectral lines revealed a local field on the bismuth nuclei. The internal magnetic field obtained by muSR significantly exceeds the dipole field from Bi nuclear magnetic moments. A possible source of

V. N. Duginov; V. G. Grebinnik; T. N. Mamedov; V. G. Olshevsky; V. Yu. Pomjakushin; V. A. Zhukov; B. F. Kirillov; B. A. Nikolsky; V. G. Orlov; A. V. Pirogov; A. N. Ponomarev; V. A. Suetin; E. A. Kravchenko

1994-01-01

166

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 yokes 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

167

Characterization of protonated phospholipids as fragile ions in quadrupole ion trap mass spectrometry  

Microsoft Academic Search

Some ions exhibit ion fragility in quadrupole ion trap mass spectrometry (QIT-MS) during mass analysis with resonance ejection. In many cases, different ions generated from the same compound exhibit different degrees of ion fragility, with some ions (e.g., the [M+H]+ ion) stable and other ions (e.g., the [M+Na]+ ion) fragile. The ion fragility for quadrupole ion trap (QIT) mass spectrometry

Timothy J. Garrett; Matthew Merves; Richard A. Yost

2011-01-01

168

Cl-NQR study of the structural order-disorder transition in (CH3NH3)2MnCl4  

Microsoft Academic Search

The temperature dependence of the Cl nuclear quadrupole resonance for the two chemically inequivalent chlorine sites in the perovskitic layer structure compound (CH3NH3)2 MnCl4 has been measured around the second order phase transition at 393.7 K. A value of the critical exponent ? of the order parameter was determined to be ? = 0.250 0.005 which is intermediate between

R. Kind; J. Roos

1976-01-01

169

Local distortions in the BiO6-octahedra sublattice of BaPbxBi1-xO3 as seen by a137Ba NMR/NQR  

NASA Astrophysics Data System (ADS)

The a137Ba NMR and NQR spectra as well as the spin-lattice relaxation rate were measured for the first time in the BaPbxBi1-xO3 samples with x = 0.91 (normal metal), x = 0.75 (superconductor) and x = 0.64 (semiconductor). The strong quadrupole broadening of the NMR lines with lowering temperature was found for all the samples. An evolution of static distortions in the BiO6-octahedra sublattice along with asymmetry of the electric field gradient at the Ba-sites is discussed. This asymmetry caused by the nearest non-cubic surrounding of barium is originated from the temperature dependent tilt of BiO6-octahedra. Spin-lattice relaxation rate of a137Ba is monitored by fluctuating part of electric field gradient at the Ba-site and its exponential growth at low temperatures evidences the thermally activated collective rotations of BiO6-octahedra around their static tilt. An activation energy and a strength of these dynamic distortions are evaluated and found to increase in going from metallic to semiconducting phase of BaPbxBi1-xO3.

Verkhovskii, S. V.; Gerashenko, A. P.; Zhdanov, Yu. I.; Mikhalev, K. N.; Sagaradze, I. V.; Medvedev, Eu. Yu.; Cheshnitskii, S. M.; Pletnev, R. N.; Kumagai, K.; Piskunov, Yu. V.; Yakubovskii, A. Yu.

1997-02-01

170

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

171

B 24 N 24 nanocages: a GIAO density functional theory study of 14 N and 11 B nuclear magnetic shielding and electric field gradient tensors  

Microsoft Academic Search

\\u000a AbstractDensity functional theory (DFT) calculations were performed to determine boron-11 and nitrogen-14 nuclear magnetic resonance\\u000a (NMR) and nuclear quadrupole resonance (NQR) spectroscopy parameters in the three most stable B24N24 fullerenes for the first time. The considered samples were first allowed to relax entirely, and then the NMR and NQR calculations\\u000a were performed on the geometrically optimized models. The calculations of

Goudarz Mohseni Rouzbehani; Asadollah Boshra; Ahmad Seif

2009-01-01

172

NQR study of local structures and cooling rate dependent superconductivity in La sub 2 CuO sub 4+. delta  

SciTech Connect

Structural properties of oxygen-annealed polycrystals of La{sub 2}CuO{sub 4 + {delta}} ({delta}{approximately}0.03) have been studied using {sup 139}La NQR spectroscopy. Superconducting critical temperatures were found to depend on the rate of cooling through a narrow temperature range at about 195K. Preliminary analysis of the {sup 139}La NQR spectra suggest that the oxygen-rich phase-separated region is composed of two structurally distinct phases, both of which are metallic and super-conducting. One phase has a structure closely related to the stoichiometric oxygen-poor compound. The second shows a considerable amount of apical oxygen disorder, a large shift in NQR frequency {nu}{sub Q}, and a volume fraction which increases with cooling rate. The formation of the second phase below {minus}200K is indicative of the freezing Of CuO{sub 6} octahedral tilting. Abrupt shifts in {nu}{sub Q} above {Tc} were also observed for both phases, suggestive of a local structural anomaly or charge transfer to the Cu-O plane.

Reyes, A.P.; Ahrens, E.T.; Hammel, P.C.; Heffner, R.H.; Thompson, J.D.; Canfield, P.C.; Fisk, Z. (Los Alamos National Lab., NM (United States)); Schirber, J.E. (Sandia National Labs., Albuquerque, NM (United States))

1992-01-01

173

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.; Knig, C.; Hagn, E.; Zech, E.; Eder, R.; Forkel, D.

1993-09-01

174

Korormicin insensitivity in Vibrio alginolyticus is correlated with a single point mutation of Gly-140 in the NqrB subunit of the Na(+)-translocating NADH-quinone reductase.  

PubMed

Na(+)-translocating NADH-quinone reductase (NQR) from the marine Vibrio alginolyticus is strongly inhibited by a new antibiotic korormicin. Korormicin specifically inhibits the Na(+)-dependent reaction of the NQR complex and acts as a purely non-competitive inhibitor for Q-1 with the inhibitor constant of 82 pM. Korormicin-resistant mutants were isolated from V. alginolyticus and the NQR complex was purified from a mutant KR2. Similar to 2-n-heptyl-4-hydroxyquinoline N-oxide (HQNO), korormicin acted as a purely noncompetitive inhibitor to the NQR complex from the mutant KR2, but the inhibitor constant increased to 8 microM, which is 10(5)-fold higher than that of the wild-type NQR complex. The inhibitor constant of HQNO, however, was only slightly affected by the acquisition of korormicin resistance. The spontaneous mutation was caused by a single mutation of G-422 to T-422 in the nucleotide sequence of the nqrB gene, which resulted in the conversion of Gly-140 to Val-140. Thus, Gly-140 seems to play an important role for the binding of korormicin to the NqrB subunit. The fact that korormicin is a purely noncompetitive inhibitor for Q-1 strongly supports the presence of one of Q-1 binding sites in the NqrB subunit, which also has a covalently bound FMN at Thr-235. PMID:12054467

Hayashi, Maki; Shibata, Naoaki; Nakayama, Yuji; Yoshikawa, Kazuhiro; Unemoto, Tsutomu

2002-05-15

175

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

176

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

177

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

178

Image restoration using fast Fourier and wavelet transforms  

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.

Harrod, William J.; Nagy, James G.; Plemmons, Robert J.

1994-02-01

179

Sodium and potassium salts of dichloroisocyanuric acid and their hydrates as antimicrobials agents studied by 35Cl-NQR spectroscopy and DFT calculations  

NASA Astrophysics Data System (ADS)

The electronic structure of dichloroisocyanuric acid derivatives was analysed by 35Cl-NQR spectroscopy and DFT calculations. Here we concentrate our attention on three different factors: type of metallic substituent (sodium and potassium), temperature of the sample (liquid nitrogen and room) and degree of hydration (an amount of water molecules attached to analysed compounds). In particular, all the variations in 35Cl-NQR frequencies upon hydration of salts containing sodium and potassium ions are explained as a consequence of H-bonds formation and accompanied effects of charge redistribution. Our studies can be useful in searching for the derivatives of dichloroisocyanuric acid revealing higher antimicrobial activity.

Walczak, A.; Brycki, B.; Kaczmarek, M.; Poleshchuk, O. Kh.; Ostafin, M.; Nogaj, B.

2006-06-01

180

NMR and NQR studies of the heavy fermion superconductors CeTIn{sub 5} (T=Co and Ir)  

SciTech Connect

We have carried out {sup 115}In and {sup 59}Co nuclear quadrupole resonance and nuclear magnetic resonance measurements on CeCoIn{sub 5} and CeIrIn{sub 5}. The temperature T dependence of the nuclear spin-lattice relaxation rate 1/T{sub 1} of {sup 115}In in the normal state indicates that CeCoIn{sub 5} is located just at an antiferromagnetic instability, and CeIrIn{sub 5} is in the nearly antiferromagnetic region. In the superconducting state, 1/T{sub 1} has no Hebel-Slichter coherence peak just below T{sub C} and a power-law T dependence (close to T{sup 3}) at very low temperatures, which indicates the existence of line nodes in the superconducting energy gap. The {sup 115}In (Ce-In plane) Knight shift in CeCoIn{sub 5} decreases for both parallel and perpendicular directions to the tetragonal c axis in the superconducting state, which shows that the spin susceptibility decreases in all directions. These results indicate that CeCoIn{sub 5} and CeIrIn{sub 5} exhibit non-s-wave even parity (probably d-wave) superconductivity.

Kohori, Y.; Yamato, Y.; Iwamoto, Y.; Kohara, T.; Bauer, E. D.; Maple, M. B.; Sarrao, J. L.

2001-10-01

181

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

182

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

183

9Be Quadrupole Perturbed NMR Study of the Ferroelectric Transition in Deuterated Triglycine Fluoberyllate  

Microsoft Academic Search

The quadrupole perturbed magnetic resonance spectra of 9Be in a deuterated triglycine fluoberyllate single crystal have been studied as a function of temperature and crystal orientation, and the electric field gradient (EFG) tensors at the Be sites have been determined in the para- and in the ferroelectric phase. The data show that the main effect of the ferroelectric transition is

R. Blinc; J. Slak; J. Stepisnik

1971-01-01

184

Quadrupole excitation of stored ion motion at the true cyclotron frequency  

Microsoft Academic Search

The motion of an ion in a Penning trap has been investigated in the presence of an azimuthal quadrupole radio frequency field and a damping force provided by buffer gas collisions. Analytical expressions are derived which describe the line shape of the cyclotron resonance as well as the properties of the mass-selective cooling mechanism for heavy ions. Excellent agreement is

M. Knig; G. Bollen; H.-J. Kluge; T. Otto; J. Szerypo

1995-01-01

185

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

186

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

187

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

188

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

189

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

190

Single-spin fluid, spin gap, and [ital d]-wave pairing in YBa[sub 2]Cu[sub 4]O[sub 8]: A NMR and NQR study  

SciTech Connect

We present results of [sup 17]O and [sup 63,65]Cu nuclear magnetic resonance (NMR) and nuclear quadrupolar resonance (NQR) studies in the normal and superconducting state of the 82-K superconductor YBa[sub 2]Cu[sub 4]O[sub 8]. The various components of the Cu and O Knight-shift tensors show strong but similar temperature dependences over the temperature range from 8.5 to 300 K in both the CuO[sub 2] planes and the chains, supporting the picture that there is only one spin component in the planes and the chains, although with different susceptibilities. The oxygen data obey the Korringa relation. This may be interpreted as Fermi-liquid behavior of the electronic system far away from the antiferromagnetic wave vector. The temperature dependence of both the planar Cu and O shift tensors and the planar Cu spin-lattice relaxation rate suggest the opening of a pseudo-spin-gap well above [ital T][sub [ital c

Bankay, M.; Mali, M.; Roos, J.; Brinkmann, D. (Physik-Institut, Universitaet Zuerich, 8057 Zuerich (Switzerland))

1994-09-01

191

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

192

Giant resonance splitting in deformed nuclei  

SciTech Connect

We describe the giant resonances as simple scaling solutions of a linearized Vlasov equation obtained from a time-dependent Hartree-Fock theory in phase space. For ellipsoidal deformed nuclei we get a splitting of the isoscalar giant quadrupole resonance proportional to the ground state charge quadrupole moment. The lower energy state (h..omega../sub parallel/ for prolate nuclei, h..omega../sub perpendicular/ for oblate) always gets the larger electromagnetic strength.

Di Nardo, M.; Di Toro, M.; Giansiracusa, G.; Lombardo, U.; Russo, G.

1983-08-01

193

Radio-frequency tunable atomic magnetometer for detection of solid-state NQR  

Microsoft Academic Search

We constructed a potassium atomic magnetometer which resonantly detects rf magnetic fields with subfemtotesla sensitivity. The resonance frequency is set by the Zeeman resonance of the potassium atoms in a static magnetic field applied to the magnetometer cell. Strong optical pumping of the potassium atoms into a stretched state reduces spin-exchange broadening of the Zeeman resonance, resulting in relatively small

S.-K. Lee; K. L. Sauer; S. J. Seltzer; O. Alem; M. V. Romalis

2007-01-01

194

Ratio of electric quadrupole to magnetic dipole amplitudes in the nucleon-delta transition  

SciTech Connect

We have analyzed available data on magnetic dipole and electric quadrupole amplitudes for the photoproduction of pions around the delta region, in the framework of a phenomenological ..gamma..N..delta.. interaction and background. The unitarity constraint via Watson's theorem limits severely the range of allowed gauge couplings in the ..gamma..N..delta.. vertex. We obtain (-1.5 +- 0.2)% as the ratio of the electric quadrupole to magnetic dipole resonant amplitudes, a value of the same order of magnitude as predicted in the skyrmion model of baryons. This ratio suggests a deformed structure of the nucleon and the delta isobar.

Davidson, R.; Mukhopadhyay, N.C.; Wittman, R.

1986-02-24

195

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

196

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

197

Microscopic magnetic nature of water absorbed Na0.35CoO2 investigated by NMR, NQR and ?+SR  

NASA Astrophysics Data System (ADS)

In order to clarify the variation of the microscopic magnetic nature with the carrier density in NaxCoO2yHO, we have measured positive muon-spin rotation/relaxation (?+SR) spectra for H2O as well as D2O absorbed samples. Based on the zero field (ZF-) ?+SR measurements, there was no clear difference between the two superconducting phases (SC-I and SC-II). Furthermore, the ZF-spectrum for the H2O absorbed sample exhibits a clear oscillation in the whole T range measured (1.4-100 K), suggesting the formation of [H3O]+-like H2?+O ions in the sample. Further, the absence of an oscillation in the D2O absorbed sample also evidences the presence of H2?+O. We also measured 59Co nuclear quadrupole resonance spectra of magnetic sample. The temperature dependence of spectra shows that there is no evidence of charge ordering and CDW ordering around magnetic transition temperature.

Ohta, Hiroto; Mnsson, Martin; Ikedo, Yutaka; Sugiyama, Jun; Michioka, Chishiro; Yoshimura, Kazuyoshi; Brewer, Jess H.; Ansaldo, Eduardo J.; Stubbs, Scott L.; Chow, Kim H.; Lord, James S.

2010-12-01

198

Enhanced spin fluctuations in the As-based filled skutterudite LaFe4As12 : A L139a NMR and A75s NQR study  

NASA Astrophysics Data System (ADS)

We have grown single crystals of the itinerant-electron weak ferromagnet LaFe4As12 (TC=3.8K) and refined its crystal structure parameters. We report experimental results of magnetic susceptibility and nuclear magnetic resonance at the La site and nuclear quadrupole resonance at the As site in the paramagnetic state for this compound. The temperature dependences of the static magnetic susceptibility, the L139a Knight shift, and the reciprocal of the product of the spin-lattice relaxation time and temperature (1/T1T) of both L139a and A75s nuclei can be consistently understood in terms of self-consistent renormalization theory of spin fluctuations for weak itinerant-electron ferromagnets.

Nowak, B.; ?oga?, O.; Pietraszko, A.; Baumbach, R. E.; Maple, M. B.; Henkie, Z.

2009-06-01

199

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

200

Giant resonances: Progress, new directions, new challenges  

SciTech Connect

A review of some recent developments in the field of giant multipole resonances is presented. Particular emphasis is placed on directions that the authors feel will be followed in this field during the next several years. In particular, the use of high-energy heavy ions to excite the giant resonances is shown to provide exciting new capabilities for giant resonance studies. Among subjects covered are: Coulomb excitation of giant resonances, photon decay of giant resonances, the recent controversy over the identity of the giant monopole resonance, the most recent value for incompressibility of nuclear matter from analysis of giant monopole data, the isospin character of the 63 A/sup /minus/1/3/ GQR, agreement between (e,e/prime/) and (hadron, hadron/prime/) excitation of the giant quadrupole resonance, prospects for multiphonon giant resonance observation, and isolation of the isovector giant quadrupole resonance. 55 refs., 23 figs., 4 tabs.

Bertrand, J.R.; Beene, J.R.

1989-01-01

201

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

202

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

203

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

204

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

205

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

206

Effect of dipole-quadrupole Robinson mode coupling upon the beam response to radio-frequency phase noise  

NASA Astrophysics Data System (ADS)

In an electron storage ring, coupling between dipole and quadrupole Robinson oscillations modifies the spectrum of longitudinal beam oscillations driven by radio-frequency (rf) generator phase noise. In addition to the main peak at the resonant frequency of the coupled dipole Robinson mode, another peak occurs at the resonant frequency of the coupled quadrupole mode. To describe these peaks analytically for a quadratic synchrotron potential, we include the dipole and quadrupole modes when calculating the beam response to generator noise. We thereby obtain the transfer function from generator-noise phase modulation to beam phase modulation with and without phase feedback. For Robinson-stable bunches confined in a synchrotron potential with a single minimum, the calculated transfer function agrees with measurements at the Aladdin 800-MeV electron storage ring. The transfer function is useful in evaluating phase feedback that suppresses Robinson oscillations in order to obtain quiet operation of an infrared beam line.

Bosch, R. A.; Kleman, K. J.

2006-09-01

207

209Bi NMR and NQR investigation of the small-gap semiconductor Ce3Bi4Pt3  

NASA Astrophysics Data System (ADS)

We report measurements of the temperature dependence of the 209Bi nuclear quadrupole resonance frequency ?Q, the Knight shift K, and the spin-lattice relaxation rate 1/T1 in the small-gap semiconductor Ce3Bi4Pt3 between 1.8 and 300 K. Corresponding measurements also are reported for the nonmagnetic metallic isomorph La3Bi4Pt3. The ?Q data in the Ce compound show a characteristic departure from metallic-to-insulating behavior when the sample is cooled below TM=80 K, the temperature of the susceptibility maximum, attributable to a loss of low-frequency vibrational modes in the insulating state. The Knight shift has both isotropic and axial components; this anisotropy originates from the presence of Ce via a transferred hyperfine coupling between Ce 4f and conduction electrons. An s-f exchange constant >=0.4 eV is found, consistent with hybridization in other rare-earth intermetallic compounds. A change in the scaling between the susceptibility and both the isotropic and axial Knight shifts at temperature TM provides evidence that hybridization between the Ce 4f orbitals and the conduction electrons is responsible for the gap structure. The temperature dependence of the 1/T1 data is consistent with a model electronic density of states possessing a temperature-independent gap ? of 180 K and a bandwidth of the order of 1600 K. The temperature dependence of 1/T1 can also be fit well with a temperature-dependent gap with ?(0) also ~=180 K.

Reyes, A. P.; Heffner, R. H.; Canfield, P. C.; Thompson, J. D.; Fisk, Z.

1994-06-01

208

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

209

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

210

NMR Imaging Using Second Order Quadrupole Broadened Resonances.  

PubMed

Theoretical and experimental results for NMR imaging measurements of powdered materials using the +(1/2) to -(1/2) transition of (1/2)-integerspin nuclei in the presence of a very large second-order electric quadrupolar broadening are presented. An "effective spin-(1/2)" formalism is developed to account for additional effects due to the presence of quadrupolar interactions comparable in size to the Zeeman interaction. A large (7.9 mT/cm-A, with a maximum current of approximately 20 A), rapid ( approximately 30 s) pulsed linear gradient field is used with echoes and phase encoding techniques to obtain images in the limit gammaH1 is much narrower than the NMR linewidth. A one-dimensional projection of the second-order quadrupolar perturbed, 4-MHz-wide, +(1/2) left and right arrow -(1/2) transition for 63Cu in Cu2O powder is presented as an example. An experimental one-dimensional projection of a sample containing Cu2O and YBa2Cu3O6.7 is also presented. Copyright 1998 Academic Press. PMID:9632553

Swaminathan; Suits

1998-06-01

211

NQR study of local structures and cooling rate dependent superconductivity in La{sub 2}CuO{sub 4+{delta}}  

SciTech Connect

Structural properties of oxygen-annealed polycrystals of La{sub 2}CuO{sub 4 + {delta}} ({delta}{approximately}0.03) have been studied using {sup 139}La NQR spectroscopy. Superconducting critical temperatures were found to depend on the rate of cooling through a narrow temperature range at about 195K. Preliminary analysis of the {sup 139}La NQR spectra suggest that the oxygen-rich phase-separated region is composed of two structurally distinct phases, both of which are metallic and super-conducting. One phase has a structure closely related to the stoichiometric oxygen-poor compound. The second shows a considerable amount of apical oxygen disorder, a large shift in NQR frequency {nu}{sub Q}, and a volume fraction which increases with cooling rate. The formation of the second phase below {minus}200K is indicative of the freezing Of CuO{sub 6} octahedral tilting. Abrupt shifts in {nu}{sub Q} above {Tc} were also observed for both phases, suggestive of a local structural anomaly or charge transfer to the Cu-O plane.

Reyes, A.P.; Ahrens, E.T.; Hammel, P.C.; Heffner, R.H.; Thompson, J.D.; Canfield, P.C.; Fisk, Z. [Los Alamos National Lab., NM (United States); Schirber, J.E. [Sandia National Labs., Albuquerque, NM (United States)

1992-10-01

212

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

213

A theoretical and experimental study of 14n quadrupole coupling in maleic hydrazide  

NASA Astrophysics Data System (ADS)

Theoretical calculations have been performed of the 14N quadrupole coupling tensor in maleic hydrazide, both as monomer and as an N-H⋯O hydrogen-bonded dimer at the orientation found in the crystal; the latter are in reasonable agreement with the experimental results obtained by double resonance and cross-relaxation spectroscopy, and reveal small changes in electron density due to the hydrogen bonding.

Palmer, M. H.; Haq, M. M. I.; Stephenson, D.; Smith, J. A. S.

1986-07-01

214

Effects of reactant ion kinetic energy on both endothermic and exothermic ion\\/molecule reactions in a quadrupole ion trap mass spectrometer  

Microsoft Academic Search

The effects of kinetic energy on the outcomes of exothermic and endothermic ion\\/molecule reactions in a quadrupole ion trap mass spectrometer are examined. Endothermic proton-transfer and charge exchange reactions may be driven in a quadrupole ion trap by acceleration of selected reactant ions to higher kinetic energies, via resonant power absorption from a supplementary a.c. voltage, prior to collisions with

Hui-Fen Wu; Jennifer S. Brodbelt

1993-01-01

215

Heavy ion excitation and photon decay of giant resonances  

SciTech Connect

Results are presented for excitation of giant multipole resonances by inelastic scattering of 350 and 500 MeV /sup 16/O projectiles from /sup 90/Zr and /sup 208/Pb. The giant quadrupole resonance is excited with large cross sections and a very large resonance peak to continuum ratio is obtained. Extracted cross sections agree with DWBA calculations which use standard collective model form factors. Using 380 MeV 170 to excite the giant resonances, the ..gamma..-ray decay has been measured for the giant quadrupole resonance region of /sup 208/Pb. 10 references.

Bertrand, F.E.; Beene, J.R.; Sjoreen, T.P.

1983-01-01

216

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

217

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

218

Resonance ionization mass spectrometry of lead and bismuth mixtures  

SciTech Connect

Resonance ionization of lead and bismuth has been demonstrated using an excimer laser pumped dye laser in three-photon, one-color ionization schemes, using a quadrupole mass spectrometer for detection.

Fearey, B.L.; Miller, C.M.; Anderson, J.E.; Nogar, N.S.; Rowe, M.W.

1988-01-01

219

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

220

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

221

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

222

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

223

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

224

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

225

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

226

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

227

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

228

Field-tuned critical fluctuations in YFe2Al10: Evidence from magnetization, 27Al NMR, and NQR investigations  

NASA Astrophysics Data System (ADS)

We report magnetization, specific heat, and NMR investigations on YFe2Al10 over a wide range of temperature and magnetic field and zero field (NQR) measurements. Magnetic susceptibility, specific heat, and spin-lattice relaxation rate divided by T(1/T1T) follow a weak power law (T-0.4) temperature dependence, which is a signature of the critical fluctuations of Fe moments. The value of the Sommerfeld-Wilson ratio and the linear relation between 1/T1T and ? suggest the existence of ferromagnetic correlations in this system. No magnetic ordering down to 50 mK in Cp(T)/T and the unusual T and H scaling of the bulk and NMR data are associated with a magnetic instability which drives the system to quantum criticality. The magnetic properties of the system are tuned by field wherein ferromagnetic fluctuations are suppressed and a crossover from quantum critical to Fermi-liquid behavior is observed with increasing magnetic field.

Khuntia, P.; Strydom, A. M.; Wu, L. S.; Aronson, M. C.; Steglich, F.; Baenitz, M.

2012-12-01

229

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

230

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

231

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

232

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

233

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

234

[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

235

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

236

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

237

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

238

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

239

Two-color photoexcitation of Rydberg states via an electric quadrupole transition  

SciTech Connect

We report the observation of an electric quadrupole transition between the 4s{sup '}[1/2]{sub 0}{sup o} and 3d[3/2]{sub 2}{sup o} states in the spectrum of argon and use it in the first step of a scheme to excite Rydberg states. The initial identification of the transition is based on one-color, two-photon photoionization. A different experiment utilizing two-color, two-photon photoexcitation to Rydberg states confirms the identification. Despite the unavoidable background of one-color, two-photon photoionization, the latter experimental technique makes possible two-photon spectroscopy of Rydberg states using a resonant intermediate state populated by an electric quadrupole transition.

Li Leping; Gu Quanli; Knee, J. L. [Department of Chemistry, Wesleyan University, Middletown, Connecticut 06459 (United States); Wright, J. D.; DiSciacca, J. M.; Morgan, T. J. [Department of Physics, Wesleyan University, Middletown, Connecticut 06459 (United States)

2008-03-15

240

Isotope effect on the temperature dependence of the 35Cl NQR frequency in (NH4)2RuCl6  

NASA Astrophysics Data System (ADS)

35Cl NQR of (NH4)2RuCl6, (ND4)2RuCl6, (NH4)2SnCl6, and (ND4)2SnCl6 was measured.Isotope effect on the spatial distribution of hydrogen atoms is discussed.Tunneling splittings of torsional ground state of ammonium ions were estimated.Origin of T1Q anomaly previously reported in (NH4)2SnCl6 and (ND4)2SnCl6 was revealed.

Kume, Yoshio; Amino, Daiki; Asaji, Tetsuo

2013-07-01

241

/sup 79/ /sup 81/Br NQR spectra of bromochalcogenide complexes of Au(III), Pt(IV), and Pd(II)  

SciTech Connect

The structure of bromochalcogenide complexes of gold, platinum, and palladium, viz., AuBr/sub 4/ x SeBr/sub 3/, PtBr/sub 6/(SeBr/sub 3/)/sub 2/, PtBr/sub 6/(TeBr/sub 3/)/sub 2/, and PdBr/sub 2/(SeBr/sub 2/)/sub 2/, has been established with the aid of the NQR spectra of the bromine atoms. In the compounds of gold and platinum investigated SeBr/sub 3/ groupings are coordinated as ligands, and in the palladium complex SeBr/sub 2/ groupings serve as ligands.

Fokina, Z.A.; Kuznetsov, S.I.; Timoshchenko, N.I.; Bryukhova, E.V.

1987-01-10

242

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

243

Pulsed power supply system for the fast quadrupoles in the AGS  

SciTech Connect

In the acceleration of polarized protons in the AGS, a number of depolarizing resonances will be encountered. Depolarization due to the so-called intrinsic resonances will be minimized by crossing each resonance in less than one beam revolution period (approx. 2 ..mu..s). This will be accomplished with a set of twelve fast tune-shifting quadrupoles distributed symmetrically around the ring. During a typical acceleration cycle, the fast quads will be energized with a burst of alternating polarity, fast rise/slow fall triangular current pulses. The amplitude of these pulses will vary from 160 A to about 2700 A peak. This paper describes the development of the pulsed power supply for the fast quads, the construction of a prototype modulator, and some of the initial test results obtained with the prototype.

Nawrocky, R.J.; Lambiase, R.F.

1983-01-01

244

Spin-isospin resonances with relativistic RPA approaches  

SciTech Connect

The relativistic RPA approaches are applied to calculate the charge-exchange spin flip resonances. Comparing the RPA calculations based on the relativistic Hartree and relativistic Hartree-Fock theories, the different physical mechanisms in determining the Gamow-Teller resonance are investigated. Then, the theoretical descriptions of spin-dipole and spin-quadrupole resonances are presented. In particular, the energy hierarchies of different components in these resonances are focused on.

Meng Jie [School of Physics and Nuclear Energy, Beihang University, Beijing 100191 (China); State Key Lab Nucl. Phys. and Tech., School of Physics, Peking University, Beijing 100871 (China); Liang Haozhao [State Key Lab Nucl. Phys. and Tech., School of Physics, Peking University, Beijing 100871 (China); Institut de Physique Nucleaire, IN2P3-CNRS and Universite Paris-Sud, 91406 Orsay (France); Nguyen Van Giai [Institut de Physique Nucleaire, IN2P3-CNRS and Universite Paris-Sud, 91406 Orsay (France)

2010-05-12

245

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

246

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

247

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

248

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

249

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

250

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

251

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

252

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

253

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

254

NQR, NMR and Crystal Structure Studies of [C(NH2)3]2HgX4 (X = Br, I)  

NASA Astrophysics Data System (ADS)

The crystal structure of [C(NH2)3]2HgBr4 has been determined at room temperature: monoclinic, space group C2/c, with a = 10.035(2), b = 11.164(2), c = 13.358(3) , ? = 111.67(3), and Z = 4. The crystal consists of planar [C(NH2)3]+ and distorted tetrahedral [HgBr4]2- ions. The Hg atom is located on a two-fold axis such that two sets of inequivalent Br atoms exist in an [HgBr4]2- ion. In accordance with the crystal structure, two 81Br NQR lines widely separated in frequency were observed between 77 and ca. 380 K. [C(NH2)3]2HgI4 yielded four 127I NQR lines ascribable to m = 1/2 ? 3/2 transitions, indicating that its crystal structure is different from the bromide complex. The 1H NMR T 1 measurements showed a single minimum for the bromide but two minima for the iodide. The analyses based on the C3 reorientations of the planar [C(NH2)3]+ ions gave the activation energies of 29.8 kJ mol-1 for the bromide, and 30.2 and 40.0 kJ mol-1 for the iodide.

Furukawa, Y.; Terao, H.; Ishihara, H.; Gesing, T. M.; Buhl, J.-C.

2004-12-01

255

NMR and NQR study of Si-doped (6,0) zigzag single-walled aluminum nitride nanotube as n or P-semiconductors.  

PubMed

Density functional theory (DFT) calculations were performed to investigate the electronic structure properties of pristine and Si-doped aluminum nitride nanotubes as n or P-semiconductors at the B3LYP/6-31G* level of theory in order to evaluate the influence of Si-doped in the (6,0) zigzag AlNNTs. We extended the DFT calculation to predict the electronic structure properties of Si-doped aluminum nitride nanotubes, which are very important for production of solid-state devices and other applications. To this aim, pristine and Si-doped AlNNT structures in two models (Si(N) and Si(Al)) were optimized, and then the electronic properties, the isotropic (CS(I)) and anisotropic (CS(A)) chemical shielding parameters for the sites of various (27)Al and (14)N atoms, NQR parameters for the sites of various of (27)Al and (14)N atoms, and quantum molecular descriptors were calculated in the optimized structures. The optimized structures, the electronic properties, NMR and NQR parameters, and quantum molecular descriptors for the Si(N) and Si(Al) models show that the Si(N) model is a more reactive material than the pristine or Si(Al) model. PMID:22588584

Baei, Mohammad T; Peyghan, Ali Ahmadi; Tavakoli, Khadijeh; Babaheydari, Ali Kazemi; Moghimi, Masoumeh

2012-05-16

256

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

257

Resonance Control Cooling System for the APT/LEDA RFQ  

SciTech Connect

The Radio Frequency Quadrupole (RFQ) resonance control cooling system (RCCS) for the Low Energy Demonstration Accelerator (LEDA) in support of the Accelerator Production of Tritium (APT) is described. Constant flow regulating valves to distribute the required flow to the 424 channels and to permit use of centrifugal pumps is discussed. Control system schema are described to regulate resonance frequency during steady state operation.

Domer, G.A.; Floersch, R.H.

1998-11-04

258

Splitting of the giant dipole resonance in the droplet model  

SciTech Connect

The droplet model is used to calculate the energy splitting of the dipole giant resonance in nuclei which have a static axially symmetric quadrupole deformation. It is shown that inclusion of the interference of Steinwedel-Jensen and Goldhaber-Teller oscillations influences the splitting of the giant dipole resonance of deformed nuclei, and that the amount of splitting depends on the atomic number.

Sinichkin, V.P.; Shekhter, L.S.

1982-06-01

259

Resonant phonon scattering of paraexcitons in Cu2O  

Microsoft Academic Search

The paraexciton in Cu2O is optically forbidden to all orders. By means of a magnetic field, it obtains oscillator strength from the quadrupole allowed orthoexciton. With an external magnetic field, we are able to excite resonantly ultracold paraexcitons. We observe a pronounced resonant Raman signal on top of the luminescence from thermalized paraexcitons. We present the magnetic-field dependence of the

Christian Sandfort; Jan Brandt; Dietmar Frhlich; Manfred Bayer; Heinrich Stolz

2008-01-01

260

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

261

Resonant (1s to 3d) X-Ray Bragg Diffraction by Transition-Metal Compounds.  

National Technical Information Service (NTIS)

Structure factors for Bragg diffraction of x-rays enhanced by electric quadrupole absorption are calculated for several configurations of the resonant ions found to exist in transition-metal compounds. The configurations include the spontaneous order (ful...

S. W. Lovesey K. S. Knight E. Balcar

2000-01-01

262

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

263

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

264

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

265

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

266

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

267

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

268

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

269

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

270

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

271

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

272

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

273

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

274

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

275

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

276

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

277

^63Cu NMR and NQR study of the stripe phase in La_1.6-xNd_0.40Sr_xCuO_4  

NASA Astrophysics Data System (ADS)

We find that the integrated intensity of ^63Cu NQR in La_1.6-xNd_0.40Sr_xCuO4 decreases dramatically below the stripe ordering temperature.(P.M. Singer et al.),Phys. Rev. B 60, 15345 (1999).(A.W. Hunt et al.),Phys. Rev. Lett. 82, 4300 (1999). Comparison with scattering results indicates that the missing signal represents the stripe order parameter. We observe that the loss of signal is sharpest for x ~1/8, indicating that x ~1/8 is the optimal concentration for stripe formation. This work was supported by the National Science Foundation (DMR 99-71266, DMR 98-08941), the A.P. Sloan Foundation, the Mitsui Foundation, and the Platzman Fund.

Singer, Philip M.; Hunt, Allen W.; Cederstrm, Agneta F.; Imai, Takashi

2000-03-01

278

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

279

Parametric-Resonance Ionization Cooling in Twin-Helix  

Microsoft Academic Search

Parametric-resonance Ionization Cooling (PIC) is proposed as the final 6D cooling stage of a highluminosity muon collider. For the implementation of PIC, we developed an epicyclic twin-helix channel with correlated optics. Wedge-shaped absorbers immediately followed by short rf cavities are placed into the twin-helix channel. Parametric resonances are induced in both planes using helical quadrupole harmonics. We demonstrate resonant dynamics

V. S. Morozov; Ya. S. Derbenev; A. Afanasev; R. P. Johnson; Erdelyi. B; J. A. Maloney

2011-01-01

280

Determination of the 14N quadrupole coupling constant of nitroxide spin probes by W-band ELDOR-detected NMR.  

PubMed

Nitroxide spin probe electron paramagnetic resonance (EPR) has proven to be a very successful method to probe local polarity and solvent hydrogen bonding properties at the molecular level. The g(xx) and the (14)N hyperfine A(zz) principal values are the EPR parameters of the nitroxide spin probe that are sensitive to these properties and are therefore monitored experimentally. Recently, the (14)N quadrupole interaction of nitroxides has been shown to be also highly sensitive to polarity and H-bonding (A. Savitsky et al., J. Phys. Chem. B 112 (2008) 9079). High-field electron spin echo envelope modulation (ESEEM) was used successfully to determine the P(xx) and P(yy) principal components of the (14)N quadrupole tensor. The P(zz) value was calculated from the traceless character of the quadrupole tensor. We introduce here high-field (W-band, 95 GHz, 3.5 T) electron-electron double resonance (ELDOR)-detected NMR as a method to obtain the (14)N P(zz) value directly, together with A(zz). This is complemented by W-band hyperfine sublevel correlation (HYSCORE) measurements carried out along the g(xx) direction to determine the principal P(xx) and P(yy) components. Through measurements of TEMPOL dissolved in solvents of different polarities, we show that A(zz) increases, while |P(zz)| decreases with polarity, as predicted by Savitsky et al. PMID:21459027

Florent, Marc; Kaminker, Ilia; Nagarajan, Vijayasarathi; Goldfarb, Daniella

2011-03-08

281

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

282

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 quadrupoleoctupole lenses. It is shown that for systems consisting of three lenses the

L. A. Baranova; F. H. Read

1999-01-01

283

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

284

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

285

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.

286

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

287

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

288

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

289

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

290

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.; Apianiz, E.; Celorrio, R.

2012-11-01

291

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

292

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

293

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

294

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

295

Designing SSC quadrupole supports to minimize the effects from vibrational noise  

SciTech Connect

G. Stupakov has shown theoretically that the emittance at the SSC should increase linearly with time and the seismic noise spectrum associated with quadrupole motion at the betatron frequency {approximately} 750--1500 Hz. While the motion is also affected by overtones of the knockout frequencies, the frequencies are so high that the seismic noise becomes vanishingly small. Feedback control would be required to control emittance growth for a power spectrum in excess of 10{sup {minus}12} microns{sup 2}/Hz, assuming unit transmission at the betatron knockout frequency through the quadrupole supports. At the 1991 Corpus Christi Workshop on Beam Dynamics, N. Dikanski predicted unacceptable emittance growths of minutes for the SSC collider in the absence of protective measures. In view of this prediction a workshop was convened in February of 1992 to discuss vibrational issues. At this workshop G. Fischer referred participants to an early study based on the then best compilation from Aki and Richards of seismic measurements. Aki and Richards showed ambient ground noise for a generic site many orders of magnitude lower than the INP measurements for the 750--1500 Hz range. Fischer referred to later extensive measurements in the US and USSR that had confirmed the Aki results and also showed that instrumental noise in the 750--1500 Hz region could dominate measurement precision. Later measurements made by the Russian group at the SSC site measure quiet noise spectra of Hz five orders of magnitude lower than the original values. Under noisy conditions measurements indicate that culturally induced vibrations might still lead to marginal emittance growth, assuming unit transmission in the relevant frequency range, and 100% efficient coupling of resonant modes to the beam. This is certainly an overestimate as relevant wavelengths are small compared with quadrupole dimensions.

Ritson, D. [Stanford Linear Accelerator Center, Menlo Park, CA (United States)]|[Superconducting Super Collider Lab., Dallas, TX (United States)

1993-09-01

296

Nuclear Quadrupole Coupling Constants in Niobium Pentachloride and Related Compounds (I) Halogen Nuclei  

NASA Astrophysics Data System (ADS)

35Cl NQR spectrum in NbCl5 has been investigated from 4.2 K to 480 K. The lines of about 7 MHz have larger multiplicity and show positive temperature dependence in contrast to the usual negative one for the line of about 13 MHz. The former lines are further separated into two groups having different temperature dependences. The expressions for the chlorine coupling constant are derived according to Townes-Daileys method on the basis of the p?-d? bond. The NQR data are analysed and the lines are assigned to the axial, equatorial and bridging chlorine atoms in the Nb2Cl10 dimer. The theory is applied to other related compounds.

Okubo, Noriaki

1982-02-01

297

Resonances and resonance widths  

SciTech Connect

Two-dimensional betatron resonances are much more important than their simple one-dimensional counterparts and exhibit a strong dependence on the betatron phase advance per cell. A practical definition of ''width'' is expanded upon in order to display these relations in tables. A primarily pedagogical introduction is given to explain the tables, and also to encourage a wider capability for deriving resonance behavior and wider use of ''designer'' resonances.

Collins, T.

1986-05-01

298

Two-photon excitation of low-lying electronic quadrupole states in atomic clusters  

SciTech Connect

A simple scheme of population and detection of low-lying electronic quadrupole modes in free small deformed metal clusters is proposed. The scheme is analyzed in terms of the time-dependent local density approximation calculations. As a test case, the deformed cluster Na{sub 11}{sup +} is considered. Long-living quadrupole oscillations are generated via resonant two-photon (two-dipole) excitation and then detected through the appearance of satellites in the photoelectron spectra generated by a probe pulse. Femtosecond pump and probe pulses with intensities I=2x10{sup 10}-2x10{sup 11} W/cm{sup 2} and pulse duration T=200-500 fs are found to be optimal. The modes of interest are dominated by a single electron-hole pair and so their energies, being combined with the photoelectron data for hole states, allow us to gather full mean-field spectra of valence electrons near the Fermi energy. Besides, the scheme allows us to estimate the lifetime of electron-hole pairs and hence the relaxation time of electronic energy into ionic heat.

Nesterenko, V. O. [Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, Dubna, Moscow region 141980 (Russian Federation); Reinhard, P.-G. [Institute of Theoretical Physics II, University of Erlangen-Nurnberg, D-91058, Erlangen (Germany); Halfmann, T. [Department of Physics, Technical University Kaiserslautern, D-67653 (Germany); Pavlov, L. I. [Institute of Electronics, Bulgarian Academy of Sciences, Sofia (Bulgaria)

2006-02-15

299

Dipole-Quadrupole Interference in the Photoionization of Cadmium Autoionizing Levels  

NASA Astrophysics Data System (ADS)

At soft x-ray energies (>1 keV) deviations from the dipole approximation may be readily observed in photoelectron angular distributions as 10% dipole-quadrupole interference effects. In the vacuum ultraviolet region the effect is much more difficult to observe since the interference term, which scales as the photon energy, is two orders of magnitude smaller. By measuring energy spectra we have succeeded in measuring a dipole-quadrupole interference resonance between J=1 and J=2 autoionizing levels in cadmium. The effects are 0.5% of the well-known(J.Jimenez-Mier, C.D.Caldwell, M.O.Krause, Phys.Rev.A 39), 95 (1989). dipole spectrum, in excellent agreement with theory. As well as being of interest in their own own right, the experiments provide an absolute reference for recent Cd (e,2e) experiments(N.L.S.Martin, D.B.Thompson, R.P.Bauman and M.Wilson, Phys. Rev. A 50), 3878 (1994)..

Martin, N. L. S.; Bauman, R. P.; Thompson, D. B.; Caldwell, C. D.; Krause, M. O.; Frigo, S. P.; Wilson, M.

1998-05-01

300

H-mode accelerating structures with permanent-magnet quadrupole beam focusing  

NASA Astrophysics Data System (ADS)

We have developed high-efficiency normal-conducting rf accelerating structures by combining H-mode resonator cavities and a transverse beam focusing by permanent-magnet quadrupoles (PMQ), for beam velocities in the range of a few percent of the speed of light. The shunt impedance of interdigital H-mode (IH-PMQ) structures is 10-20 times higher than that of a conventional drift-tube linac, while the transverse size is 4-5 times smaller. Results of the combined 3D modelingelectromagnetic computations, multiparticle beam-dynamics simulations with high currents, and thermal-stress analysisfor an IH-PMQ accelerator tank are presented. The accelerating-field profile in the tank is tuned to provide the best propagation of a 50-mA deuteron beam using coupled iterations of electromagnetic and beam-dynamics modeling. Measurements of a cold model of the IH-PMQ tank show a good agreement with the calculations. Examples of cross-bar H-mode structures with PMQ focusing for higher beam velocities are also presented. H-PMQ accelerating structures following a short radio-frequency quadrupole accelerator can be used both in the front end of ion linacs or in stand-alone applications.

Kurennoy, S. S.; Rybarcyk, L. J.; O'Hara, J. F.; Olivas, E. R.; Wangler, T. P.

2012-09-01

301

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 systems center-of-mass-energy frame; we find the binarys 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, anna .

2013-07-01

302

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

303

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

304

Dynamics of a strongly interacting Fermi gas: The radial quadrupole mode  

SciTech Connect

We report on measurements of an elementary surface mode in an ultracold, strongly interacting Fermi gas of {sup 6}Li atoms. The radial quadrupole mode allows us to probe hydrodynamic behavior in the crossover from Bose-Einstein condensation (BEC) to the Bardeen-Cooper-Schrieffer (BCS) regime without being influenced by changes in the equation of state. We examine the frequency and damping of this mode, along with its expansion dynamics. In the unitarity limit and on the BEC side of the resonance, the observed frequencies agree with standard hydrodynamic theory. However, on the BCS side of the crossover, a striking downshift of the oscillation frequency is observed in the hydrodynamic regime as a precursor to an abrupt transition to collisionless behavior; this indicates coupling of the oscillation to fermionic pairs.

Altmeyer, A.; Wright, M. J.; Kohstall, C.; Denschlag, J. Hecker [Institute of Experimental Physics and Center for Quantum Physics, University of Innsbruck, 6020 Innsbruck (Austria); Riedl, S.; Grimm, R. [Institute of Experimental Physics and Center for Quantum Physics, University of Innsbruck, 6020 Innsbruck (Austria); Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, 6020 Innsbruck (Austria)

2007-09-15

305

Electric-Dipole{endash}Quadrupole Interference of Overlapping Autoionizing Levels in Photoelectron Energy Spectra  

SciTech Connect

We have measured the photon energy dependence of electric-dipole{endash}quadrupole interference in cadmium between the odd parity 4d{sup 9}5s{sup 2}5p J=1 and even parity 5p6p {sup 3} P{sub 2} autoionizing levels. The resonant interference structure is isolated by taking the difference between constant ionic state spectra at 45{degree} with respect to the photon beam in the forward and backward directions. We find interference effects that are approximately 0.5{percent} of the dipole cross section for photon energies of 13thinspeV, in good agreement with theory. We compare the results with those from (e,thinsp2e) experiments. {copyright} {ital 1998} {ital The American Physical Society }

Martin, N.L.; Thompson, D.B.; Bauman, R.P. [Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506-0055 (United States); Caldwell, C.D.; Krause, M.O.; Frigo, S.P. [Department of Physics, University of Central Florida, Orlando, Florida 32816 (United States); Wilson, M. [Physics Department, Royal Holloway, University of London, Egham, Surrey TW20 0EX (United Kingdom)

1998-08-01

306

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

307

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

308

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 Garca; Gmez, Francisco; Lago, Santiago; Garzn, Benito

2011-06-21

309

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

310

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

311

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

312

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

313

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

314

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

315

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.; Prez, C.; Cabezas, C.; Lpez, J. C.; Caminati, W.

2011-09-01

316

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

317

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

318

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

319

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

320

Low-Field Knight Shift Measurement at Sb Site for Alkaline-Earth Filled Skutterudites AFe4Sb12 (A = Sr and Ca)  

Microsoft Academic Search

121Sb Knight shift K measurement has been carried out by applying a perturbing field to the nuclear quadrupole resonance (NQR) spectrum in alkaline-earth filled skutterudites AFe4Sb12 (A = Ca and Sr), which are close to ferromagnetic instability. The hyperfine coupling constant was determined for the first time as -14.9 kOe\\/muB f.u. from the K-chi plot. This relatively large value suggests

Atsurou Sakurai; Masahiro Matsumura; Harukazu Kato; Takashi Nishioka; Eiichi Matsuoka; Katsuyuki Hayashi; Toshirou Takabatake

2008-01-01

321

Mutual Orientations of the Principal Axes of the Electric-Field Gradient Tensors on 14N and 81Br by Combined Zeeman-Effect Measurements in a Single Crystal of p-Bromoaniline  

Microsoft Academic Search

The Zeeman effect of the nuclear quadrupole resonance of both 14N and 81Br nuclei in a single crystal of p-bromoaniline was studied. The precision of the technique used here is far greater than that of the few previous works in this field. Measurements were made by means of a newly designed spectrometer, working at both 14N and 81Br NQR frequencies,

A. Colligiani; R. Ambrosetti; P. Cecchi

1971-01-01

322

Tuning multiple Fano resonances in plasmonic pentamer clusters  

NASA Astrophysics Data System (ADS)

Multiple Fano resonances in plasmonic pentamer clusters composed of nanorings are observed and investigated. Molecular point group theory is used to understand the formation of multiple Fano resonances. By modifying the radius of the center ring or the angle between the center and the surrounding rings, the modulation depths and the spectral positions of the multiple Fano resonances can be tuned within a wide range. For pentamers composed of split nanorings, another Fano resonance can be excited because of the excitation of the quadrupole mode of the surrounding split nanorings.

Liu, Shao-Ding; Zhang, Ming-Jiang; Wang, Wen-Jie; Wang, Yun-Cai

2013-04-01

323

CROSSING A COUPLING SPIN RESONANCE WITH AN RF DIPOLE.  

SciTech Connect

In accelerators, due to quadrupole roll errors and solenoid fields, the polarized proton acceleration often encounters coupling spin resonances. In the Brookhaven AGS, the coupling effect comes from the solenoid partial snake which is used to overcome imperfection resonances. The coupling spin resonance strength is proportional to the amount of coupling as well as the strength of the corresponding intrinsic spin resonance. The coupling resonance can cause substantial beam polarization loss if its corresponding intrinsic spin resonance is very strong. A new method of using an horizontal rf dipole to induce a full spin flip crossing both the intrinsic and its coupling spin resonances is studied in the Brookhaven's AGS. Numerical simulations show that a full spin flip can be induced after crossing the two resonances by using a horizontal rf dipole to induce a large vertical coherent oscillation.

BAI,M.; ROSER,T.

2001-06-18

324

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

325

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

326

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

327

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 1960s. 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.

328

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

329

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. Hhnermann; K. Mandrek; H. Ihle

1972-01-01

330

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

331

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

332

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

333

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

334

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

335

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

336

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

337

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

338

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

339

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

340

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

341

Novel methods for detecting buried explosive devices  

SciTech Connect

Oak Ridge National Laboratory (ORNL) and Quantum Magnetics, Inc. (QM) are exploring novel landmine detection technologies. Technologies considered here include bioreporter bacteria, swept acoustic resonance, nuclear quadrupole resonance (NQR), and semiotic data fusion. Bioreporter bacteria look promising for third-world humanitarian applications; they are inexpensive, and deployment does not require high-tech methods. Swept acoustic resonance may be a useful adjunct to magnetometers in humanitarian demining. For military demining, NQR is a promising method for detecting explosive substances; of 50,000 substances that have been tested, none has an NQR signature that can be mistaken for RDX or TNT. For both military and commercial demining, sensor fusion entails two daunting tasks, identifying fusible features in both present-day and emerging technologies, and devising a fusion algorithm that runs in real-time on cheap hardware. Preliminary research in these areas is encouraging. A bioreporter bacterium for TNT detection is under development. Investigation has just started in swept acoustic resonance as an approach to a cheap mine detector for humanitarian use. Real-time wavelet processing appears to be a key to extending NQR bomb detection into mine detection, including TNT-based mines. Recent discoveries in semiotics may be the breakthrough that will lead to a robust fused detection scheme.

Kercel, S.W.; Burlage, R.S.; Patek, D.R.; Smith, C.M. [Oak Ridge National Lab., TN (United States); Hibbs, A.D.; Rayner, T.J. [Quantum Magnetics, Inc., San Diego, CA (United States)

1997-04-01

342

Novel methods for detecting buried explosive devices  

NASA Astrophysics Data System (ADS)

Oak Ridge National Laboratory and Quantum Magnetics, Inc. are exploring novel landmine detection technologies. Technologies considered here include bioreporter bacteria, swept acoustic resonance, nuclear quadrupole resonance (NQR), and semiotic data fusion. Bioreporter bacteria look promising for third-world humanitarian applications; they are inexpensive, and deployment does not require high-tech methods. Swept acoustic resonance may be a useful adjunct to magnetometers in humanitarian demining. For military demining, NQR is a promising method for detecting explosive substances; of 50,000 substances that have been tested, one has an NQR signature that can be mistaken for RDX or TNT. For both military and commercial demining, sensor fusion entails two daunting tasks, identifying fusible features in both present-day and emerging technologies, and devising a fusion algorithm that runs in real-time on cheap hardware. Preliminary research in these areas is encouraging. A bioreporter bacterium for TNT detection is under development. Investigation has just started in swept acoustic resonance as an approach to a cheap mine detector for humanitarian use. Real-time wavelet processing appears to be a key to extending NQR bomb detection into mine detection, including TNT-based mines. Recent discoveries in semiotics may be the breakthrough that will lead to a robust fused detection scheme.

Kercel, Stephen W.; Burlage, Robert S.; Patek, David R.; Smith, Cyrus M.; Hibbs, Andrew D.; Rayner, Timothy J.

1997-07-01

343

Supramolecular synthon pattern in solid clioquinol and cloxiquine (APIs of antibacterial, antifungal, antiaging and antituberculosis drugs) studied by 35 Cl NQR, 1 H- 17 O and 1 H- 14 N NQDR and DFT\\/QTAIM  

Microsoft Academic Search

The quinolinol derivatives clioquinol (5-chloro-7-iodo-8-quinolinol, Quinoform) and cloxiquine (5-chloro-8-quinolinol) were\\u000a studied experimentally in the solid state via 35Cl NQR, 1H-17O and 1H-14N NQDR spectroscopies, and theoretically by density functional theory (DFT). The supramolecular synthon pattern of OHN\\u000a hydrogen bonds linking dimers and ?? stacking interactions were described within the QTAIM (quantum theory of atoms in molecules)\\u000a \\/DFT (density functional theory)

Jolanta Natalia Latosi?ska; Magdalena Latosi?ska; Marzena Agnieszka Tomczak; Janez Seliger; Veselko agar

344

Nuclear magnetic resonance of 198Au and 199Au oriented in a hcp cobalt single crystal at low temperatures  

NASA Astrophysics Data System (ADS)

We report the first observation of quadrupole-interaction-resolved nuclear magnetic resonance on oriented nuclei in a hexagonal Co host. The radioactive isotopes 198Au and 199Au were mass separator implanted into a hcp Co single crystal and nuclear magnetic resonance was detected via the anisotropy of the ? radiation at temperatures of ~10 mK. These experiments have shown that hcp Co might be the best host matrix for the determination of the electric quadrupole moments of heavy radioactive nuclei with resonance precision.

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

1988-09-01

345

95Mo magic angle spinning NMR at high field: improved measurements and structural analysis of the quadrupole interaction in monomolybdates and isopolymolybdates.  

PubMed

In this study, 95Mo quadrupole couplings in various molydbates were measured easily and accurately with magic angle spinning (MAS) NMR under a directing field of 19.6 T. The resonance frequency of 54 MHz was sufficiently high to remove acoustic ringing artifacts, and the spectra could be analyzed in the usual terms of chemical shift and quadrupolar line shapes. For monomolybdates and molybdite, the quadrupole coupling dominated the NMR response, and the quadrupole parameters could be measured with better accuracy than in previous lower field studies. Moreover, despite the low symmetry of the molybdenum coordination, the usefulness of such measurements to probe molybdenum environments was established by ab initio density functional theory (DFT) calculations of the electric field gradient from known structures. The experimental NMR data correlated perfectly with the refined structures. In isopolymolybdates, the resonances were shapeless and DFT calculations were impossible because of the large and low symmetry unit cells. Nevertheless, empirical but clear NMR signatures were obtained from the spinning sidebands analysis or the MQMAS spectra. This was possible for the first time thanks to the improved baseline and sensitivity at high fields. With the generalization of NMR spectrometers operating above 17 T, it was predicted that 95Mo MAS NMR could evolve as a routine characterization tool for ill-defined structures such as supported molybdates in catalysis. PMID:16852762

d'Espinose de Lacaillerie, Jean-Baptiste; Barberon, Fabien; Romanenko, Konstantin V; Lapina, Olga B; Polls, Laurent Le; Gautier, Rgis; Gan, Zhehong

2005-07-28

346

Characterization of protonated phospholipids as fragile ions in quadrupole ion trap mass spectrometry  

PubMed Central

Some ions exhibit ion fragility in quadrupole ion trap mass spectrometry (QIT-MS) during mass analysis with resonance ejection. In many cases, different ions generated from the same compound exhibit different degrees of ion fragility, with some ions (e.g., the [M+H]+ ion) stable and other ions (e.g., the [M+Na]+ ion) fragile. The ion fragility for quadrupole ion trap (QIT) mass spectrometry (MS) for protonated and sodiated ions of three phospholipids, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine, PC (16:0/16:0), 1,2-dipalmitoyl-sn-glycero-3-phophoethanolamine, PE (16:0/16:0), and N-palmitoyl-D-erythro-sphingosylphosphorylcholine, SM (d18:1/16:0), was determined using three previously developed experiments: 1) the peak width using a slow scan speed, 2) the width of the isolation window for efficient isolation, and 3) the energy required for collision-induced dissociation. In addition, ion fragility studies were designed and performed to explore a correlation between ion fragility in QIT mass analysis and ion fragility during transport between the ion source and the ion trap. These experiments were: 1) evaluating the amount of thermal-induced dissociation as a function of heated capillary temperature, and 2) determining the extent of fragmentation occurring with increasing tube lens voltage. All phospholipid species studied exhibited greater ion fragility as protonated species in ion trap mass analysis than as sodiated species. In addition, the protonated species of both SM (d18:0/16:0) and PC (16:0/16:0) exhibited greater tendencies to fragment at higher heated capillary temperatures and high tube lens voltages, whereas the PE (16:0/16:0) ions did not appear to exhibit fragility during ion transport.

Garrett, Timothy J.; Merves, Matthew; Yost, Richard A.

2011-01-01

347

Characterization of protonated phospholipids as fragile ions in quadrupole ion trap mass spectrometry.  

PubMed

Some ions exhibit "ion fragility" in quadrupole ion trap mass spectrometry (QIT-MS) during mass analysis with resonance ejection. In many cases, different ions generated from the same compound exhibit different degrees of ion fragility, with some ions (e.g., the [M+H](+) ion) stable and other ions (e.g., the [M+Na](+) ion) fragile. The ion fragility for quadrupole ion trap (QIT) mass spectrometry (MS) for protonated and sodiated ions of three phospholipids, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine, PC (16:0/16:0), 1,2-dipalmitoyl-sn-glycero-3-phophoethanolamine, PE (16:0/16:0), and N-palmitoyl-D-erythro-sphingosylphosphorylcholine, SM (d18:1/16:0), was determined using three previously developed experiments: 1) the peak width using a slow scan speed, 2) the width of the isolation window for efficient isolation, and 3) the energy required for collision-induced dissociation. In addition, ion fragility studies were designed and performed to explore a correlation between ion fragility in QIT mass analysis and ion fragility during transport between the ion source and the ion trap. These experiments were: 1) evaluating the amount of thermal-induced dissociation as a function of heated capillary temperature, and 2) determining the extent of fragmentation occurring with increasing tube lens voltage. All phospholipid species studied exhibited greater ion fragility as protonated species in ion trap mass analysis than as sodiated species. In addition, the protonated species of both SM (d18:0/16:0) and PC (16:0/16:0) exhibited greater tendencies to fragment at higher heated capillary temperatures and high tube lens voltages, whereas the PE (16:0/16:0) ions did not appear to exhibit fragility during ion transport. PMID:22247650

Garrett, Timothy J; Merves, Matthew; Yost, Richard A

2011-12-01

348

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

349

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

350

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

351

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

352

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

353

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

354

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

355

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

356

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

357

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

358

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

359

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

360

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

361

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

362

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

363

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

364

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

365

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

366

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

367

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

368

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

369

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

370

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

371

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

372

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

373

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

374

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

375

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

376

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

377

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

378

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

379

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

380

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

381

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 mm23.0 mm hollow conductor for the quadrupoles. Due to

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

1994-01-01

382

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

383

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

384

Comprehensive two-dimensional gas chromatographyquadrupole mass spectrometric analysis of drugs  

Microsoft Academic Search

The use of comprehensive two-dimensional gas chromatography coupled to quadrupole mass spectrometry (GC GCqMS) for drug screening is investigated with 77 underivatised drug standards in methanolic solution. The GC GCqMS setup involved a reduced mass scan range of 42235u 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

385

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

386

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

387

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

388

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

389

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

390

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

391

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

392

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

393

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.

394

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

395

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

396

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

397

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

398

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

399

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.

Rodrguez-Guzmn, R. R.; Egido, J. L.; Robledo, L. M.

2003-03-01

400

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.; Wrtche, H.-J.

1992-11-01

401

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

402

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

403

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

404

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

405

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

406

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

407

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=21030 kc\\/sec. Since this disagrees significantly with the present experimental estimate [(eqQ\\/h)D=10050 kc\\/sec], a more refined measurement

T. Caves; M. Karplus

1966-01-01

408

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

409

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

410

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

411

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

412

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

413

Adaptation of a 3-D Quadrupole Ion Trap for Dipolar DC Collisional Activation  

PubMed Central

Means to allow for the application of a dipolar DC pulse to the end-cap electrodes of a three-dimensional (3-D) quadrupole ion trap for as short as a millisecond to as long as hundreds of milliseconds are described. The implementation of dipolar DC does not compromise the ability to apply AC waveforms to the end-cap electrodes at other times in the experiment. Dipolar DC provides a nonresonant means for ion acceleration by displacing ions from the center of the ion trap where they experience stronger rf electric fields, which increases the extent of micro-motion. The evolution of the product ion spectrum to higher generation products with time, as shown using protonated leucine enkephalin as a model protonated peptide, illustrates the broad-band nature of the activation. Dipolar DC activation is also shown to be effective as an ion heating approach in mimicking high amplitude short time excitation (HASTE)/pulsed Q dissociation (PQD) resonance excitation experiments that are intended to enhance the likelihood for observing low m/z products in ion trap tandem mass spectrometry.

Prentice, Boone M.; Santini, Robert E.; McLuckey, Scott A.

2011-01-01

414

Matched and equipartitioned design method for modern high-intensity radio frequency quadrupole accelerators  

NASA Astrophysics Data System (ADS)

A new design methodMatched and equipartitioned (EP) design methodhas been proposed for radio frequency quadrupole (RFQ) dynamics design, on the considerations of preventing emittance growth and halo formation in high-intensity linacs by means of keeping beam envelope matched and energy balance within the beam, as well as avoiding structure resonances [R.A. Jameson, IEEE Trans. Nucl. Sci. NS-28 (1981) 2408; R.A. Jameson et al., Scaling and optimization in high-intensity linear accelerators, LA-CP-91-272, Los Alamos National Laboratory, July 1991 (introduction of LINACS design code); R.A. Jameson, AIP Conf. Proc. 279 (1992) 969; R.A. Jameson, An approach to fundamental study of beam loss minimization, in: Y.K. Batygin (Ed.), AIP Conference Proceedings, vol. 480, Space Charge Dominated Beam Physics for Heavy Ion Fusion, Saitama, Japan, December 1998]. As there are more than three parameters for a linear accelerator, but only three equations (two envelope equations and an EP equation) are available to design the structural parameters of the RFQ accelerator around the beam, therefore the others have to be determined by additional rules. Following these equations and rules, a new RFQ design code named MATCHDESIGN has been written at Peking University. Three example designs are generated by this code and their simulation results have been compared with a conventional RFQ, which had proved the feasibilities and merits of the new method.

Yan, X. Q.; Jameson, R. A.; Lu, Y. R.; Guo, Z. Y.; Fang, J. X.; Chen, J. E.

2007-07-01

415

DETECTION OF EXPLOSIVES BY QUADRUPOLE RESONANCE METHOD: NEW ASPECTS FOR SECURITY  

Microsoft Academic Search

A very important part of aviation security is the detection and identification of explosives in baggage. There are many detection\\u000a techniques employing a range of different technologies that are based on physical and chemical properties of such substances.\\u000a At present the most widely used screening technique employs transmission X-ray imaging. The method is based on the irradiation\\u000a of baggage by

T. N. RUDAKOV; T. J. RAYNER; P. A. HAYES; K. L. RUSSETH

416

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; Maes, Jordi; Pic, Yolanda

2005-03-01

417

Isovector quadrupole excitations in the valence shell of the vibrator nucleus 136Ba: Evidence from photon scattering experiments  

NASA Astrophysics Data System (ADS)

Photon scattering experiments have been performed on the nucleus 136Ba with photon energies of E?<=4.1 MeV and E?<=2.8 MeV. At 2.1 MeV clear evidence for the 2+ms state has been found. From the measured lifetime we extract signatures for the isovector quadrupole excitation in the valence shell: a weakly collective E2 decay to the ground state and a strong M1 decay to the 2+1 state. As the resonant photon scattering with bremsstrahlung is a complete reaction, we can conclude that the 2+ state at 2129 keV is a rather pure 2+ms state with little fragmentation. This is in contrast to the 1+ scissors state. A comparison with an IBM-2 calculation is given.

Pietralla, N.; Belic, D.; von Brentano, P.; Fransen, C.; Herzberg, R.-D.; Kneissl, U.; Maser, H.; Matschinsky, P.; Nord, A.; Otsuka, T.; Pitz, H. H.; Werner, V.; Wiedenhver, I.

1998-08-01

418

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

419

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

420

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

421

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

422

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

423

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

424

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

425

Confinement of multiply charged ions in an electron cyclotron resonance heated mirror plasma  

Microsoft Academic Search

Multiply charged ions are studied in the Constance B quadrupole mirror experiment (Phys. Rev. Lett. {bold 59}, 1821 (1987)) in order to better understand the ion physics of electron cyclotron resonance (ECR) high charge-state ion sources. By measuring the ion densities and end loss fluxes, the parallel confinement times for the first five charge states of oxygen plasmas are determined.

C. C. Petty; D. L. Goodman; D. L. Smatlak; D. K. Smith

1991-01-01

426

Confinement of multiply charged ions in an electron cyclotron resonance heated mirror plasma  

Microsoft Academic Search

Multiply charged ions are studied in the Constance B quadrupole mirror experiment [Phys. Rev. Lett. 59, 1821 (1987)] in order to better understand the ion physics of electron cyclotron resonance (ECR) high charge-state ion sources. By measuring the ion densities and end loss fluxes, the parallel confinement times for the first five charge states of oxygen plasmas are determined. The

C. C. Petty; D. L. Goodman; D. L. Smatlak; D. K. Smith

1991-01-01

427

Inelastic scattering of /sup 9/Be of 27 MeV/A to giant resonances  

SciTech Connect

Inelastic scattering spectra have been measured with 245 MeV incident energy /sup 9/Be ions on a /sup 208/Pb target. They show large excitation of the /sup 208/Pb giant quadrupole resonance. Distorted-wave Born-approximation calculations are reported and compared with the data.

Lebrun, D.; Buenerd, M.; Bini, M.; Harvey, B.G.; Legrain, R.; Mahoney, J.; Symons, T.J.M.; Van Bibber, K.

1981-01-01

428

Nuclear Magnetic Resonance Evidence Using D2O for Structured Water in Muscle and Brain.  

National Technical Information Service (NTIS)

The electric quadrupole moment of the deuterium nucleus provides a nuclear magnetic resonance (NMR) probe of electric field gradients, and thereby of organization of tissue water. 8-17% of H2O in rat muscle and brain was replaced by D2O from 50% deuterate...

F. W. Cope

1968-01-01

429

Coupling of vibration modes in a resonant antenna for gravitational radiation  

Microsoft Academic Search

Multi-mode operation of resonant antennas for gravitational radiation improves their sensitivity provided that each mode is independent. We examined the correlation between the oscillations of two quadrupole modes in a disk antenna. The vibrations were observed for 200 hours and no recognizable correlation was found.

Akihiko Mizutani; Kimio Tsubono

1989-01-01

430

Deuteron Magnetic Resonance Study of Cupric Sulfate Pentahydrate  

Microsoft Academic Search

A deuteron magnetic resonance study is made of single crystals of CuSO45D2O between 130 and 360K. The electric quadrupole coupling constant, the asymmetry parameter, and the directions of the principal axes of the field-gradient tensor are determined for each deuteron at 133.2 and 294.8K. At low temperatures ten pairs of lines are observed, corresponding to five nonequivalent stationary water molecules.

Gen Soda; Takehiko Chiba

1969-01-01

431

Magnetic resonance cell  

SciTech Connect

There is disclosed a nuclear magnetic alignment device for use in a nuclear magnetic resonance gyroscope and the like. One embodiment includes a container for gas having a layer of rubidium hydride on its inner surface. The container comprising a spherical portion and a tip portion, is rotationally symmetric about an axis of symmetry. Enclosed within the container is a nuclear moment gas having a nuclear electric quadrupole moment, such as xenon-131, and an optically pumpable substance, such as rubidium. A portion of the rubidium is a vapor. The remainder is a condensed pellet which is deposited in the tip of the container such that the pellet is also rotationally symmetric about the axis of symmetry of the container. A layer of rubidium hydride is deposited on the inner surface of the container. The device further includes means for orienting the symmetry axis of the container at an angle to an applied magnetic field such that the relaxation time constant of the aligned nuclear moment gas is substantially at a maximum.

Kwon, T.M.; Volk, C.H.

1984-05-01

432

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

LCMSMS 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 MSMS ion of the target compounds. Confirmation of the identity of the pharmaceuticals was based either on the monitoring of two specific MSMS

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

2004-01-01

433

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

434

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

435

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

436

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

437

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

438

Single-particle resonances in a deformed Dirac equation  

SciTech Connect

Single-particle bound and resonant states are obtained by solving the Dirac equation with quadrupole-deformed Woods-Saxon potential in coordinate space with the coupled-channel approach. Taking the m{sup {pi}}=1/2{sup +} resonant states at deformation {beta}=0.1 as examples, the roles of their spherical components have been investigated based on the behaviors of the eigenphases and the corresponding probabilities weighted by the scalar spherical potential. It is shown that the realization of the m{sup {pi}}=1/2{sup +} resonances is supported mainly by the lnot =0 components, and the mixture of the s{sub 1/2} component can lead to the disappearance of some resonances at finite energy. The dominance of the lnot =0 component (d{sub 3/2}) in the small-energy region guarantees the continuation of a certain resonance to the corresponding bound state.

Li, Z. P.; Zhang, Y. [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Meng, J. [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191 (China); Institute of Theoretical Physics, Chinese Academy of Science, Beijing 100190 (China); Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 730000 (China); Zhou, S. G. [Institute of Theoretical Physics, Chinese Academy of Science, Beijing 100190 (China); Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 730000 (China); Savushkin, L. N. [Department of Physics, St. Petersburg University for Telecommunications, RU-191065 St. Petersburg (Russian Federation)

2010-03-15

439

Gamma decay of isovector giant resonances built on highly excited states in 111Sn  

Microsoft Academic Search

Gamma-ray transition-energy spectra up to Egamma~=33 MeV have been measured for the decay of the compound nucleus 111Sn* populated at excitation energies up to E*~=100 MeV. Above Egamma~=20 MeV an excess of gamma rays over the contribution from the isovector giant dipole resonance is observed in the energy range where the isovector giant quadrupole resonance built on excited states is

J. J. Gaardhje; C. Ellegaard; B. Herskind; R. M. Diamond; M. A. Deleplanque; G. Dines; A. O. Macchiavelli; F. S. Stephens

1986-01-01

440

Nuclear magnetic resonance of 155Gd and 157Gd nuclei in gadolinium iron garnet  

Microsoft Academic Search

The magnetic resonance of 155Gd and 157Gd nuclei was detected in GdIG at liquid helium temperature by a spin echo method. The resonance frequencies (40.5 and 54Mc\\/sec) correspond to the effective field of 338 kOe. This value is consistent with the known hyperfine coupling constant of Gd3+ in different compounds. The observed splittings were ascribed to quadrupole interaction.

Le Dang Kho

1969-01-01

441

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

442

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

443

Nuclear spin-lattice relaxation-time reduction in small particles  

NASA Astrophysics Data System (ADS)

A method is described of reducing the nuclear spin-lattice relaxation time in a polycrystalline solid without the introduction of any paramagnetic impurities. It relies on the fact that the relaxation times of nuclei on a surface are usually much shorter than those in the bulk due to greater freedom of movement. Simply reducing the particle size by grinding or other methods is shown to be effective in markedly reducing the spin-lattice relaxation time of all the nuclei in the specimen because of the good thermal contact between like nuclei in the interior and surface of small particles. The nuclear quadrupole resonance (NQR) of 14N, 2D, or 23Na was measured for the same specimens with different particle sizes by nuclear quadrupole double resonance to ensure that the chemical structure of the compound did not alter due to the grinding. In all samples studied, except sodium thiosulphate, the NQR spectrum was unaffected by the grinding except that the time necessary to collect the data was reduced. In the case of sodium thiosulphate a marked change in the NQR spectrum was observed despite the fact that no change in chemical composition could be detected. Data is presented which demonstrates the effectiveness of the technique and a simple model of the underlying mechanism is described.

Rabbani, S. R.; Edmonds, D. T.

1994-09-01

444

Theta-shaped plasmonic nanostructures: bringing "dark" multipole plasmon resonances into action via conductive coupling.  

PubMed

Quadrupole plasmon and (octupolar) Fano resonances are induced in lithographically fabricated theta-shaped ring-rod gold nanostructures. The optical response is characterized by measuring the light scattered by individual nanostructures. When the nanorod is brought within 3 nm of the ring wall, a weak quadrupolar resonance is observed due to capacitive coupling, and when a necklike conductive bridge links the nanorod to the nanoring the optical response changes dramatically bringing the quadrupolar resonance into prominence and creating an octupolar Fano resonance. The Fano resonance is observed due to the destructive interference of the octupolar resonance with the overlapping and broadened dipolar resonance. The quadrupolar and Fano resonances are further enhanced by capacitive coupling (near-field interaction) that is favored by the theta-shaped arrangement. The interpretation of the data is supported by FDTD simulation. PMID:21425843

Habteyes, Terefe G; Dhuey, Scott; Cabrini, Stefano; Schuck, P James; Leone, Stephen R

2011-03-22

445

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

446

Stochastic resonance  

NASA Astrophysics Data System (ADS)

Over the last two decades, stochastic resonance has continuously attracted considerable attention. The term is given to a phenomenon that is manifest in nonlinear systems whereby generally feeble input information (such as a weak signal) can be be amplified and optimized by the assistance of noise. The effect requires three basic ingredients: (i) an energetic activation barrier or, more generally, a form of threshold; (ii) a weak coherent input (such as a periodic signal); (iii) a source of noise that is inherent in the system, or that adds to the coherent input. Given these features, the response of the system undergoes resonance-like behavior as a function of the noise level; hence the name stochastic resonance. The underlying mechanism is fairly simple and robust. As a consequence, stochastic resonance has been observed in a large variety of systems, including bistable ring lasers, semiconductor devices, chemical reactions, and mechanoreceptor cells in the tail fan of a crayfish. In this paper, the authors report, interpret, and extend much of the current understanding of the theory and physics of stochastic resonance. They introduce the readers to the basic features of stochastic resonance and its recent history. Definitions of the characteristic quantities that are important to quantify stochastic resonance, together with the most important tools necessary to actually compute those quantities, are presented. The essence of classical stochastic resonance theory is presented, and important applications of stochastic resonance in nonlinear optics, solid state devices, and neurophysiology are described and put into context with stochastic resonance theory. More elaborate and recent developments of stochastic resonance theory are discussed, ranging from fundamental quantum properties-being important at low temperatures-over spatiotemporal aspects in spatially distributed systems, to realizations in chaotic maps. In conclusion the authors summarize the achievements and attempt to indicate the most promising areas for future research in theory and experiment.

Gammaitoni, Luca; Hnggi, Peter; Jung, Peter; Marchesoni, Fabio

1998-01-01

447

Excitation and photon decay of giant multipole resonances - the role and future of medium-energy heavy ions  

SciTech Connect

Inelastic scattering of medium energy heavy ions provides very large cross sections and peak-to-continuum ratios for excitation of giant resonances. For energies above about 50 MeV/nucleon, giant resonances are excited primarily through Coulomb excitation, which is indifferent to isospin, thus providing a good probe for the study of isovector giant resonances. The extremely large cross sections available from heavy ion excitation permit the study of rare decay modes of the photon decay of giant resonances following excitation by 22 and 84 MeV/nucleon /sup 17/O projectiles. The singles results at 84 MeV/nucleon yield peak cross sections for the isoscalar giant quadrupole resonance and the isovector giant dipole resonance of approximately 0.8 and 3 barns/sr, respectively. Data on the ground state decay of the isoscalar giant quadrupole and isovector giant dipole resonances are presented and compared with calculations. Decays to low-lying excited states are also discussed. Preliminary results from an experiment to isolate the /sup 208/Pb isovector quadrupole resonance using its gamma decay are presented.

Bertrand, F.E.; Beene, J.R.; Horen, D.J.

1988-01-01

448

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),G2(?).

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

1980-06-01

449

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

450

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

451

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

452

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

453

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

454

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

455

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

456

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

457

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

458

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

459

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

460

Dibaryon Resonances.  

National Technical Information Service (NTIS)

New degrees of freedom, like mesons and baryonic resonance on one band, or quarks and color on the other hand, can lead to possible exotic states of baryonic number 2. Large resonances have indeed been observed in both elastic and inelastic nucleon-nucleo...

B. Mayer

1987-01-01