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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

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

NASA Astrophysics Data System (ADS)

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

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

2006-06-01

3

Nuclear quadrupole resonance detection of explosives: an overview  

NASA Astrophysics Data System (ADS)

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

Miller, Joel B.

2011-05-01

4

New technologies: nuclear quadrupole resonance as an explosive and narcotic detection technique  

Microsoft Academic Search

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.

Vadim S Grechishkin; Nikolai Ya Sinyavskii

1997-01-01

5

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

6

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

7

Nuclear quadrupole resonance of boron in borate glasses  

NASA Astrophysics Data System (ADS)

A continuous wave nuclear quadrupole resonance spectrometer that has a high sensitivity even at low frequencies has been built. Boron and aluminum NQR has been detected in the region 200 kHz to 1.4 MHz. For the first time, boron NQR has been detected in a glass. The NQR spectrum of pure B 20 3 glass is consistent with 85 2% of the boron atoms belonging to boroxol rings. In sodium borate glasses, the number of borons in boroxol rings decreases with increasing sodium content, until when sodium oxide comprises 20 mol% of the glass less than 2% of the borons are in boroxol rings.

Gravina, Samuel J.; Bray, Phillip J.

8

Correlation of far-infrared and nuclear quadrupole resonance studies in 1,3,5-tribromobenzene  

NASA Astrophysics Data System (ADS)

The torsional modes that contribute to the change in nuclear quadrupole resonance (NQR) frequencies with temperatures in 1,3,5-tribromobenzene are indentified by correlating the observed variation of 79Br NQR frequencies with temperature with the theoretical expectations using the low frequency vibrational modes obtained from the far-infrared (FIR) spectrum.

Venkatacharyulu, P.; Krishnamurthy, V.

1991-02-01

9

The two-frequency nuclear quadrupole resonance for explosives detection  

Microsoft Academic Search

The two-frequency nuclear quadrupole resonance (NQR) of14N nuclei is described for purposes of explosives detection. Two applications are known: two-frequency NQR for increasing the\\u000a signal intensity, two-frequency NQR for improved reliability of explosives detection. The two-frequency experiments were carried\\u000a out in hexahydro-1,3,5-trinitro-s-triazine C3H6N6O6 and sodium nitrite NaNO2 as a substitute for octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocycine C4H8N8O8. The two-frequency sequences for NQR are proposed

G. V. Mozjoukhine

2000-01-01

10

Optimal filtering in multipulse sequences for nuclear quadrupole resonance detection  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

11

Wavelet-based enhancements to nuclear quadrupole resonance explosives detectors  

NASA Astrophysics Data System (ADS)

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

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

1998-03-01

12

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

13

Nuclear quadrupole resonance lineshape analysis for different motional models: stochastic Liouville approach.  

PubMed

A general theory of lineshapes in nuclear quadrupole resonance (NQR), based on the stochastic Liouville equation, is presented. The description is valid for arbitrary motional conditions (particularly beyond the valid range of perturbation approaches) and interaction strengths. It can be applied to the computation of NQR spectra for any spin quantum number and for any applied magnetic field. The treatment presented here is an adaptation of the "Swedish slow motion theory," [T. Nilsson and J. Kowalewski, J. Magn. Reson. 146, 345 (2000)] originally formulated for paramagnetic systems, to NQR spectral analysis. The description is formulated for simple (Brownian) diffusion, free diffusion, and jump diffusion models. The two latter models account for molecular cooperativity effects in dense systems (such as liquids of high viscosity or molecular glasses). The sensitivity of NQR slow motion spectra to the mechanism of the motional processes modulating the nuclear quadrupole interaction is discussed. PMID:22168707

Kruk, D; Earle, K A; Mielczarek, A; Kubica, A; Milewska, A; Moscicki, J

2011-12-14

14

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

15

Fundamentals of Pulsed Nitrogen-14 Quadrupole Resonance  

NASA Astrophysics Data System (ADS)

The essential features of nitrogen-14 Nuclear Quadrupole Resonance, a new tool based on density matrix calculations is proposed. After a brief review of the density matrix theory, it is demonstrated that, for each of the three NQR transitions, the (3,3) density matrix can be reduced to a (2,2) matrix, evidently easier to handle. (2,2) rotation matrices are defined for predicting, in a straightforward manner, the system evolution under a rf pulse. The first example treated by this methodology concerns nutation experiments (evolution of the signal amplitude as a function of the pulse length) and it is shown that the NMR (Nuclear Magnetic Resonance) flip angle, in the case of powder samples, should be substituted by a pseudo flip angle which is no longer proportional to the pulse length. Still for powder samples, it is demonstrated that, in NQR, data averaging continuously improves when shortening the repetition time. Finally it has been possible to define proper phase cycles in view of measuring relaxation times (T1 and T2) by a two-pulse sequence. In all cases, experimental verifications were performed in order to assess this methodology.

Canet, Daniel; Ferrari, Maude

16

Low-temperature nuclear quadrupole resonance studies of antimony and application to thermometry  

Microsoft Academic Search

The spin-lattice retaxation time, Tsb1, of finely divided powdered metallic antinomy immersed in liquid sp3He was measured using pulsed Nuclear Quadrupole Resonance (NQR) techniques. In this technique, the nuclear quadrupole resonant antinomy nuclei were saturated using an RF pulse. The recovery back to equilibrium was monitored using short inspection pulses and the magnetization recovery follows a recovery curve characterized by

Edgar Baylon Genio

1997-01-01

17

Antitank and Antipersonnel Mine Detection Test Results for a Nuclear Quadrupole Resonance Detection System.  

National Technical Information Service (NTIS)

This report summarizes the results of an interim test of a system that uses the nuclear quadrupole resonance (NQR) signature of explosives for the detection of antipersonnel (AP) and antitank (AT) land mines. The system, designed and built by Quantum Magn...

F. S. Rotondo E. Ayers

2000-01-01

18

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

SciTech Connect

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

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

1998-06-01

19

Sensing of chemical substances using SQUID-based nuclear quadrupole resonance  

NASA Astrophysics Data System (ADS)

Using a high- Tc radio frequency superconducting quantum interference device (rf SQUID) with a normal metal transformer, we successfully detected the nuclear quadrupole resonance (NQR) at about 888 kHz of 14N in p-nitrotoluene (PNT) at room temperature. Only one coil was used as the resonator coil for the transmission and the pickup coil of the transformer. To reduce the influence of the strong excitation field, cross diodes and switches were inserted in the transformer. The signal-to-noise ratio of the NQR spectrum using high- Tc rf SQUID system was comparable to that of using a low noise preamplifier.

Tachiki, M.; He, D. F.; Itozaki, H.

2007-10-01

20

14N nuclear quadrupole resonance of p-nitrotoluene using a high-Tc rf SQUID  

NASA Astrophysics Data System (ADS)

Using a high-Tc radio-frequency superconducting quantum interference device (rf SQUID), we successfully detected nuclear quadrupole resonance (NQR) at about 887 kHz for 14N in p-nitrotoluene (PNT). A normal metal transformer made of copper wire was used to improve the sensitivity of the high-Tc rf SQUID and pulse-controlled rf switches and cross diodes were inserted in the transformer to reduce the influence of the strong excitation field. The preliminary results for NQR detection using the high-Tc SQUID had a similar signal-to-noise ratio to that of using a low noise preamplifier.

He, D. F.; Tachiki, M.; Itozaki, H.

2007-03-01

21

Nuclear quadrupole resonance of explosives: Simultaneous detection of RDX and PETN in semtex  

Microsoft Academic Search

We have used nuclear quadrupole resonance (NQR) for the detection of14N in explosives and introduce a new method for the simultaneous detection of the explosives cyclotrimethylene trinitramine\\u000a (RDX) and pentaerythritol tetranitrate (PETN). We have developed an interleaved pulse sequence, which provides efficient excitation\\u000a of both RDX and PETN, to drive a solenoid coil that is doubly resonant at 3.41 and

R. I. Jenkinson; J. M. Bradley; G. N. Shilstone

2004-01-01

22

Unconventional superconductivity in ferromagnetic UGe2: a 73Ge nuclear magnetic resonance\\/nuclear quadrupole resonance study  

Microsoft Academic Search

We report 73Ge nuclear magnetic resonance\\/nuclear quadrupole resonance (NMR\\/NQR) measurements on the itinerant ferromagnetic superconductor UGe2 at ambient pressure (P = 0) and P = 1.3 GPa. Measurements of the nuclear spin-lattice relaxation rate 1\\/T1 of the 73Ge NMR at P = 0 have revealed a T1T = constant behaviour well below TCurie = 52 K, evidencing the presence of

H. Kotegawa; S. Kawasaki; A. Harada; Y. Kawasaki; K. Okamoto; G.-q. Zheng; Y. Kitaoka; E. Yamamoto; Y. Haga; Y. Onuki; K. M. Itoh; E. E. Haller

2003-01-01

23

Detection of plastic explosives in luggage with 14 N nuclear quadrupole resonance spectroscopy  

Microsoft Academic Search

Nuclear quadrupole resonance (NQR) of14N nuclei has many advantages as a method for detecting nitrogen-containing explosives, the most important are very high chemical\\u000a specificity, true noninvasive operation and detection of bulk explosive in situ only (no vapor or particular capture needed).\\u000a One of the most high explosives is hexogen (RDX) often used by terrorists in plasticized forms. The ring nitrogen

M. Ostafin; B. Nogaj

2000-01-01

24

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

PubMed

We report Cd nuclear magnetic resonance (NMR) and Re nuclear quadrupole resonance (NQR) studies on Cd(2)Re(2)O(7), the first superconductor among pyrochlore oxides (T(c) approximately 1 K). The Re NQR spectrum at zero magnetic field below 100 K rules out any magnetic or charge order. The spin-lattice relaxation rate below T(c) exhibits a pronounced coherence peak and follows the weak-coupling BCS theory with nearly isotropic energy gap. The results of Cd NMR point to a moderate ferromagnetic enhancement at high temperatures followed by a rapid decrease of the density of states below the structural transition temperature of 200 K. PMID:12097064

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

2002-07-01

25

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

26

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

PubMed

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. PMID:23231223

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

2012-12-01

27

INDO Investigation of the halogen N.Q.R. frequencies and 14 N nuclear quadrupole coupling constants of halothiophenes and halopyridines  

Microsoft Academic Search

The 35Cl, 79Br, and 127I N.Q.R. frequencies of a number of halothiophenes and halopyridines and the 14N nuclear quadrupole coupling constants of halopyridines have been determined in terms of the Kaplansky-Whitehead theory with the INDO MO approximations using a consistent set of atomic parameters derived from SCF Hartree-Fock calculations. The theoretical spectral properties are in satisfactory overall agreement with experiment.

V. Galasso

1974-01-01

28

Stark effect of 14N NQR in single crystals of ferroelectric NaNO2  

Microsoft Academic Search

The effects of the external electric field on 14N nuclear quadrupole resonance (NQR) have been investigated in the ferroelectric phase of sodium nitrite (NaNO2) single crystals with either the single domain or the multidomain structure. NQR measurements of two resonance lines of n and n were made at 77 K under the external electric field up to 25 kV\\/cm. The

S. H. Choh; Y. J. Park; H. K. Kim; Y. M. Chang

1989-01-01

29

High precision measurement of the 11Li and 9Li quadrupole moment ratio using zero-field ?-NQR  

NASA Astrophysics Data System (ADS)

The ratio of electric quadrupole moments of 11Li and 9Li was measured using the zero-field ?-detected nuclear quadrupole resonance technique at Triumf-Isac. The precision on the ratio Q11/Q9 = 1.0775(12) was improved by more than one order of magnitude and an absolute value for the quadrupole moment of 11Li was inferred. Systematic effects, as argued here, are not expected to contribute to the ratio on this scale. The zero-field spin-lattice relaxation time for 8Li implanted within SrTiO3 at 295?K in zero-field was found to be T1 = 1.73(2)?s. A comparison of the quadrupole moments of 9, 11Li and their ratio is made with the latest models, however, no conclusion may yet be drawn owing to the size of the theoretical uncertainties.

Voss, A.; Pearson, M. R.; Buchinger, F.; Crawford, J. E.; Kiefl, R. F.; Levy, C. D. P.; MacFarlane, W. A.; Man, E.; Morris, G. D.; Shelbaya, O. T. J.; Song, Q.; Wang, D.

2014-01-01

30

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

31

Radio frequency quadrupole resonator for linear accelerator  

DOEpatents

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

Moretti, Alfred (Downers Grove, IL)

1985-01-01

32

Nuclear quadrupole resonance and nuclear magnetic resonance of copper in the high-T/sub c/ superconductor YBa/sub 2/Cu/sub 3/O/sub 7-//sub delta/  

SciTech Connect

The /sup 65/Cu and /sup 63/Cu zero-field nuclear quadrupole resonance (NQR), nuclear magnetic resonance (NMR) at 4.7 and 8.5 T and the spin-lattice relaxation time T/sub 1/ at 8.5 T are measured in the superconducting oxide YBa/sub 2/Cu/sub 3/O/sub 7-//sub delta/ between 80 and 300 K. No sign of magnetic order or localized moments are found. The NQR linewidth is strongly dependent on the oxygen content. We assign the /sup 63/Cu NQR line at 22 MHz to the Cu site with oxygen coordination 5. T/sub 1/ is dominated by the quadrupolar relaxation due to spin-phonon coupling.

Furo, I.; Janossy, A.; Mihaly, L.; Banki, P.; Pocsik, I.; Bakonyi, I.; Heinmaa, I.; Joon, E.; Lippmaa, E.

1987-10-01

33

Multi-Frequency Resonances in Pure Multiple-Pulse NQR  

NASA Astrophysics Data System (ADS)

We have observed multi-frequency resonances in a system with a spin 3/2 irradiated simultaneously by a multiple-pulse radiofrequency sequence and a low frequency field swept in the range 0 80 kHz. The theoretical description of the effect is presented using both the rotating frame approximation and the Floquet theory. Both approaches give indentical results at the calculation of the resonance frequencies, transition probabilities and shifts of resonance frequency. The calculated magnetization vs. the frequency of the low-frequency field agrees with the obtained experimental data.

Furman, G. B.; Kibrik, G. E.; Polyakov, A. Yu.

2004-12-01

34

Numerical simulation of NQR/NMR: Applications in quantum computing.  

PubMed

A numerical simulation program able to simulate nuclear quadrupole resonance (NQR) as well as nuclear magnetic resonance (NMR) experiments is presented, written using the Mathematica package, aiming especially applications in quantum computing. The program makes use of the interaction picture to compute the effect of the relevant nuclear spin interactions, without any assumption about the relative size of each interaction. This makes the program flexible and versatile, being useful in a wide range of experimental situations, going from NQR (at zero or under small applied magnetic field) to high-field NMR experiments. Some conditions specifically required for quantum computing applications are implemented in the program, such as the possibility of use of elliptically polarized radiofrequency and the inclusion of first- and second-order terms in the average Hamiltonian expansion. A number of examples dealing with simple NQR and quadrupole-perturbed NMR experiments are presented, along with the proposal of experiments to create quantum pseudopure states and logic gates using NQR. The program and the various application examples are freely available through the link http://www.profanderson.net/files/nmr_nqr.php. PMID:21324720

Possa, Denimar; Gaudio, Anderson C; Freitas, Jair C C

2011-04-01

35

Cooperative Phenomenon of Ferromagnetism and Unconventional Superconductivity in UGe2: A 73Ge-NQR Study under Pressure  

Microsoft Academic Search

We report on a cooperative phenomenon of ferromagnetism and unconventional superconductivity (SC) in UGe2 through the measurements of 73Ge nuclear-quadrupole-resonance (NQR) under pressure (P). The NQR spectra evidenced phase separation into ferromagnetic and paramagnetic phases in the vicinity of Pc 1.5 GPa, pointing to a first-order transition. The measurements of nuclear-spin-lattice-relaxation-rate 1\\/T1 revealed that SC emerges under the background of

Atsushi Harada; Shinji Kawasaki; Hisashi Kotegawa; Yoshio Kitaoka; Yoshinori Haga; Etsuji Yamamoto; Yoshichika Onuki; K. M. Itoh; Eugene Haller; Hisatomo Harima

2005-01-01

36

Cooperative Phenomenon of Ferromagnetism and Unconventional Superconductivity in UGe2: A 73Ge-NQR Study under Pressure  

NASA Astrophysics Data System (ADS)

We report on a cooperative phenomenon of ferromagnetism and unconventional superconductivity (SC) in UGe2 through the measurements of 73Ge nuclear-quadrupole-resonance (NQR) under pressure (P). The NQR spectra evidenced phase separation into ferromagnetic and paramagnetic phases in the vicinity of Pc 1.5 GPa, pointing to a first-order transition. The measurements of nuclear-spin-lattice-relaxation-rate 1/T1 revealed that SC emerges under the background of ferromagnetism, but not of the paramagnetic phase.

Harada, A.; Kawasaki, S.; Kotegawa, H.; Kitaoka, Y.; Haga, Y.; Yamamoto, E.; ?nuki, Y.; Itoh, K. M.; Haller, E. E.; Harima, H.

2005-10-01

37

Investigation of Structural Information for Boron - Solids and Aluminates via NMR and Nqr Studies.  

NASA Astrophysics Data System (ADS)

Nuclear Magnetic Resonance (NMR) has been prevailed in investigating local structures for a variety of materials: various oxide glasses, zeolites, superconductors, etc. Since glasses have short range ordered structures instead of long range ordered ones in crystals, NMR is usually more useful in determining the local structures for many glasses than any other detection methods do. Along with NMR, Nuclear Quadrupole Resonance (NQR) has become important recently for obtaining structural information from such glasses. The NQR studies prove in this thesis that they provide more accurate structural information than the NMR studies have done. This study presents boron and aluminum NMR, and NQR studies for some borate glasses and compounds, icosahedral boron-rich solids, some crystalline aluminosilicates. Various borates were employed to acquire structural information as well as to determine the quadrupole parameters (the quadrupole coupling constant Q_{cc } and the asymmetry parameter eta ) using NQR under a guidance of NMR or vice versa. By NQR a previously unknown boron site was observed for vitreous Li_2OcdotB _2O_3. The boron site had an intermediate Q_{cc } value in-between the reported value ranges of Q_{cc} for BO _3 and BO_4 sites, and was concluded to be a previously unknown BO _4 site. The NMR and NQR studies were performed on some icosachedral boron-rich solids: alpha -rhombohedral boron (B_{12}), beta-boron (B_{105 }) and boron carbide (B_{12 }C_3). Strong NQR responses were obtained from boron atoms in the C-B-C chains along with several other NQR responses from boron atoms in the icosahedral. These NQR results were consistent with the NMR studies by Silver and Bray, and those by Hynes and Alexander. Also, for the icosahedral boron-rich solids, the ^{11}B NMR studies revealed the possibility of chemical shifts due to two distinct boron sites in the icosahedra. A very interesting phenomenon was found from an isotopic change of boron nuclei (substitution of ^{10}B for ^{11}B) in boron carbide: in ^{11}B high field (7.05 Tesla) NMR spectra, two distinct peaks separated by some chemical shifts for unenriched boron carbide (B _{12}C_3) became a single peak for ^{10} B enriched boron carbide (90.61 at.% of ^{10}B). Three different forms of crystalline aluminosilicate (Al_2SiO_5) were studied by NQR. The NQR study yielded more accurate values of the quadrupole parameters for ^ {27}Al than the previous NMR single crystal study did.

Lee, Donghoon

38

Nuclear quadrupole spin dynamics: How weak RF pulses and double resonance cross-relaxation contribute to explosives detection  

NASA Astrophysics Data System (ADS)

Nuclear quadrupole resonance (NQR) is a type of radio-frequency (rf) spectroscopy which can detect quadrupolar nuclei (I > 1/2), such as nitrogen, in crystalline solids. NQR spectroscopy is useful for the detection of the many types of explosives containing 14N, however it suffers from a low signal to noise ratio (SNR) particularly in samples with long spin-lattice relaxation times. To improve the SNR the nuclear quadrupole spin dynamics are exploited in two limiting cases: systems with long spin relaxation times and systems where the excitation power is limited. The former is addressed through double resonance effects and the latter through spin echoes created by weak rf pulses. The double resonance effect occurs in samples that also contain a second faster relaxing nuclear species, such as 1H in ammonium nitrate. In this sample an 1H-14N double resonance can be created between the species that improves the SNR. While the focus is on the common case of solids containing both nitrogen and hydrogen, the theory is generally applicable to solids containing spin-1 and spin-1/2 nuclei. A model of this system is developed that treats the motionally averaged secular dipolar Hamiltonian as a perturbation of the combined quadrupole and Zeeman Hamiltonians. This model reveals three types of double resonance conditions, involving static and rf fields, and predicts expressions for the cross-relaxation rate (Wd) between the two species. Using this cross-relaxation rate, in addition to the hydrogen and nitrogen autorelaxation rates, expressions governing the relaxation back to equilibrium in a spin-1/2 and spin-1 system are determined. The three different types of double resonance conditions are created experimentally; one of them for the first time in any system and another for the first time in a solid. Under these double resonance conditions, the increase in Wd and improvements in SNR are explored both theoretically and experimentally using ammonium nitrate. The second effect investigated is the NQR spin echo that forms after excitation of a powder sample by a single weak resonant radio-frequency pulse. This single-pulse echo is identified for the first time, and when applications are limited by a weak rf field, can be used effectively to increase the SNR over conventional detection techniques.

Prescott, David

39

Development of a quadrupole resonance confirmation system  

NASA Astrophysics Data System (ADS)

Quantum Magnetics has developed a Quadrupole Resonance (QR) system for the detection of anti-tank and anti-vehicle landmines. The QR confirmation sensor (QRCS) is a part of the Army GSTAMIDS Block 1 program and is designed to confirm the presence of landmines initially flagged by a primary sensor system. The ultimate goal is to significantly reduce the number of sites that require neutralization or other time consuming investigation into the presence of a landmine. Government tests in 2002 and 2003 demonstrated the performance of the system in a wide variety of conditions including high radio frequency interference (RFI) and piezo electric ringing (PER) environments. Field test results are presented along with an overall description of the system design and methods used to solve prior issues with RFI and PER.

Barrall, Geoffrey A.; Derby, Kevin A.; Drew, Adam J.; Ermolaev, Konstantine V.; Huo, Shouqin; Lathrop, Daniel K.; Petrov, Todor R.; Steiger, Matthew J.; Stewart, Stanley H.; Turner, Peter J.

2004-09-01

40

Quadrupole resonance spectroscopic study of narcotic materials  

NASA Astrophysics Data System (ADS)

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

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

1997-02-01

41

Evolution of an Unconventional Superconducting State inside the Antiferromagnetic Phase of CeNiGe3 under Pressure: A 73Ge-Nuclear-Quadrupole-Resonance Study  

NASA Astrophysics Data System (ADS)

We report a 73Ge nuclear-quadrupole-resonance (NQR) study on novel evolution of unconventional superconductivity in antiferromagnetic (AFM) CeNiGe3. The measurements of the 73Ge-NQR spectrum and the nuclear spin-lattice relaxation rate (1/T1) have revealed that the unconventional superconductivity evolves inside a commensurate AFM phase around the pressure (P) where Nel temperature TN exhibits its maximum at 8.5 K. The superconducting transition temperature TSC has been found to be enhanced with increasing TN, before reaching the quantum critical point at which the AFM order collapses. Above TSC, the AFM structure transits from an incommensurate spin-density-wave order to a commensurate AFM order at T 2 K, accompanied by a longitudinal spin-density fluctuation. With regard to heavy-fermion compounds, these novel phenomena have hitherto never been reported in the P-T phase diagram.

Harada, Atsushi; Mukuda, Hidekazu; Kitaoka, Yoshio; Thamizhavel, Arumugam; Okuda, Yusuke; Settai, Rikio; ?nuki, Yoshichika; Itoh, Kouhei M.; Haller, Eugene E.; Harima, Hisatomo

2008-10-01

42

Optimised NQR pulse technique for the effective detection of Heroin Base.  

PubMed

The nuclear quadrupole resonance (NQR) method has been applied to Heroin Base (HB) to find an optimised multi-pulse technique for effective detection of HB. Experimental results of applying the proposed spin-locking multi-pulse (SLMP) technique to nitrogen-14 NQR in this sample are presented and convincingly demonstrate as a path towards efficient detection. A detection using a sequence of this character could be achieved over real-world scan volumes for screening of goods. All experiments were carried out at room temperature. PMID:18342493

Rudakov, T N; Hayes, P A; Flexman, J H

2008-03-01

43

Negative group velocity from quadrupole resonance of plasmonic spheres  

NASA Astrophysics Data System (ADS)

We study the dispersion relations of plasmonic bands that arise from the coupling of electric-quadrupole resonances in three-dimensional plasmonic lattices consisting of metallic nanospheres. Through analytical derivation, we show that two branches of quadrupole bands in simple-cubic lattices with a small lattice constant possess negative group velocities. Distinct from double negative (?,?<0) media in which the negative dispersion originates from the coupling of electric and magnetic responses ( P and M ), the negative dispersion induced by quadrupole resonance is an intrinsic property of quadrupole that does not require coupling to another degree of freedom. In addition, the quadrupole dispersions are intrinsically anisotropic, which defies a simple isotropic effective-medium description without spatial dispersion even though the lattice constant is small compared with the wavelength. In plasmonic systems composed of metallic nanoparticle clusters, the coupled quadrupole resonance may be tuned to lower optical frequency and the coupling strength between this quadrupole resonance and external electromagnetic (EM) waves could be in the same order of magnitude as the magnetic dipole M .

Han, Dezhuan; Lai, Yun; Fung, Kin Hung; Zhang, Zhao-Qing; Chan, C. T.

2009-05-01

44

Evidence for Ca substituting Ba in YBa 2- xCa xCu 4O 8 y: a nuclear quadrupole resonance investigation  

NASA Astrophysics Data System (ADS)

For the understanding of the Tc enhancement in Ca doped YBa 2Cu 4O 8 y it is crucial to know which crystallographic site the Ca +2 ion is occupying. We investigated this problem by measuring the Cu nuclear quadrupole resonance (NQR) spectrum at 100 K in YBa 2Cu 4O 8 y doped with 10% Ca ( Tc = 91 K). The NQR lines of the plane and chain Cu sites appear at the same frequencies vq as in the pure compound, however, both lines are broadend by static defects. Within the linewidths no temperature dependence of vq was observed and no indication for magnetic ordering at the Cu sites was found. At 20 600 Mhz, near to the Cu(1) line, a resonance line has been detected which is absent in the pure YBa 2- xCa xCu 4O 8 y spectrum. Based on NQR arguments we assign this new line to Cu(1) nuclei whose electric field gradients are disturbed by Ca +2 ions occupying Ba +2 sites. We concluded that a major fraction of Ca ions occupy Ba sites, therefore the increase of Tc by Ca doping cannot be explained by an increase of the hole concentration.

Mangelschots, I.; Mali, M.; Roos, J.; Zimmermann, H.; Brinkmann, D.; Rusiecki, S.; Karpinski, J.; Kaldis, E.; Jilek, E.

1990-12-01

45

35Cl NQR of an organic ferroelectric phenazine chloranilic acid co-crystal  

NASA Astrophysics Data System (ADS)

A ferroelectric transition of phenazine (Phz) chloranilic acid (H 2ca) co-crystal was studied by 35Cl nuclear quadrupole resonance (NQR). The single NQR line observed at 36.689 MHz at 295 K, split into a doublet below the ferroelectric transition temperature Tc=253 K in accord with the inversion-symmetry breaking at the H 2ca molecular center in the crystal. The continuous variation of the splitting-width through Tc suggests a second-order nature of this phase transition. The NQR frequency is consistent with the crystal structure in which the two acid hydrogen atoms of H 2ca remain as attached to the quinone molecules. The spin-lattice relaxation time T1 showed a decrease with decreasing temperature in the ferroelectric phase. This suggests the existence of a fast motion of nearby atomic group, which is a cause of electric field gradient fluctuation.

Asaji, Tetsuo; Gotoh, Kazuma; Watanabe, Jun

2006-06-01

46

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

47

Radio-frequency quadrupole resonator for linear accelerator  

DOEpatents

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

Moretti, A.

1982-10-19

48

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

49

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

50

Spectra of nuclear quadrupole resonance in vitreous semiconductors  

SciTech Connect

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

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

2006-09-15

51

14N NQR in the tetrazole family  

NASA Astrophysics Data System (ADS)

14N NQR frequencies and spin-lattice relaxation times were measured in technologically important 5-aminotetrazole and 5-aminotetrazole monohydrate at different temperatures between 77 K and 300 K. Five NQR triplets ?+, ?- and ?0 were found for the five inequivalent nitrogen atoms in each compound between 0.7 MHz and 4 MHz. Carr-Purcell based multipulse sequences were used to accumulate quadrupole echo signals before the FFT analysis. Assignment of the frequencies to atomic positions was made and the results are analysed in relation to the molecular chemical bonds and possible H-bonds in the crystal structures. The new NQR frequencies are reasonably related to the previously published NQR spectrum of the third family member, 1H-tetrazole.

Pirnat, Janez; Lunik, Janko; Jazbinek, Vojko; agar, Veselko; Seliger, Janez; Klaptke, Thomas M.; Trontelj, Zvonko

2009-10-01

52

Low-temperature nuclear quadrupole resonance studies of antimony and application to thermometry  

NASA Astrophysics Data System (ADS)

The spin-lattice retaxation time, Tsb1, of finely divided powdered metallic antinomy immersed in liquid sp3He was measured using pulsed Nuclear Quadrupole Resonance (NQR) techniques. In this technique, the nuclear quadrupole resonant antinomy nuclei were saturated using an RF pulse. The recovery back to equilibrium was monitored using short inspection pulses and the magnetization recovery follows a recovery curve characterized by the relaxation time Tsb1. Tsb1 measurements were performed at temperatures ranging from 150 mK to 1.25 mK. Temperatures down to 11 mK were achieved by using a dilution refrigerator. Lower temperatures were achieved using adiabatic nuclear demagnetization of a copper bundle starting at 8.5 Tesla (7.5 Tesla average field over the copper bundle). The sample was cooled by immersion in liquid sp3He which is in thermal contact with silver sinter packed in the bottom of a silver cell. This cell was bolted onto a cold plate attached to the copper bundle. It was found that a low temperatures starting near 75 mK, the measured total relaxation was significantly enhanced with respect to the Korringa relaxation, the dominant relaxation mechanism expected for a metal at these temperatures. This enhancement is attributed to a surface relaxation mechanism mediated by the surface sp3He atoms. In systems immersed in liquid sp3He, a surface relaxation mechanism is present due to a modulation of the interaction between the solid-like sp3He atoms on the surface and the surface spins. This modulation is due to the quantum zero-point motion of the sp3He atoms on the surface. This phenomenon has been well studied in insulating systems using Nuclear Magnetic Resonance. The measurements undertaken in this study demonstrate that this phenomenon is present in a metallic and quadrupolar system. This surface relaxation mechanism becomes the dominant relaxation mechanism at low temperatures. Considering the surface and bulk spins as belonging to different phases, a two phase relaxation analysis was used to extract the surface relaxation parameters. This work helps explain previous relaxation measurements by other groups, on powdered metals (with spin I? 0) immersed in liquid sp3He. In these studies, anomalies were reported whose features are consisted with the surface relaxation mechanism discussed in this work. Using magnetic field perturbed NQR, the intensity ratio of two transitions was studied from 1.4 mK to 0.25 mK. The intensity ratio was observed to change as a function of temperature. A comparison is made with the expected Boltzmann distribution. This intensity ratio can be used as a self-calibrating, absolute thermometer for the ultra-low temperature region.

Genio, Edgar Baylon

1997-11-01

53

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

SciTech Connect

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

Jayakody, J.R.P.

1993-12-31

54

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

55

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

56

Application of the spherical tensor method for Two-Frequency pure NQR of spin I =1 nuclei  

Microsoft Academic Search

The results of a theoretical investigation of two-frequency excitation in pure nuclear quadrupole resonance (NQR) for a spinI=1 nucleus with a nonaxial elecric field gradient are presented. The multipole tensor operator technique is used for the treatment\\u000a of the one- and two-frequency pulse excitations. The results are applied to the characterization of the two-frequency signal\\u000a of nitrogen14N nuclei. The experiments

G. V. Mozjoukhine

2002-01-01

57

Possible Multiple Gap Superconductivity with Line Nodes in Heavily Hole-Doped Superconductor KFe2As2 Studied by 75As Nuclear Quadrupole Resonance and Specific Heat  

NASA Astrophysics Data System (ADS)

We report the 75As nuclear quadrupole resonance (NQR) and specific heat measurements of the heavily hole-doped superconductor KFe2As2 (superconducting transition temperature Tc? 3.5 K). The spin-lattice relaxation rate 1/T1 in the superconducting state exhibits a gradual temperature dependence with no coherence peak below Tc. The quasiparticle specific heat CQP/T shows a small jump, which is about 30% of the electronic specific heat coefficient just below Tc. The CQP/T suggests the existence of low-energy quasiparticle excitation at the lowest measurement temperature T=0.4 K? Tc/10. The T dependences of 1/T1 and CQP/T can be explained by a multiple nodal superconducting gap scenario rather than by a multiple fully gapped s-wave scenario determined using simple gap analysis.

Fukazawa, Hideto; Yamada, Yuji; Kondo, Kenji; Saito, Taku; Kohori, Yoh; Kuga, Kentarou; Matsumoto, Yosuke; Nakatsuji, Satoru; Kito, Hijiri; Shirage, Parasharam M.; Kihou, Kunihiro; Takeshita, Nao; Lee, Chul-Ho; Iyo, Akira; Eisaki, Hiroshi

2009-08-01

58

Advances in the engineering of quadrupole resonance landmine detection systems  

NASA Astrophysics Data System (ADS)

Advances in the engineering of Quadrupole Resonance (QR) sensors for landmine detection have resulted in improved performance, as well as massive reductions in power, size and weight. The next generation of vehicle-mounted QR confirmation sensors is over an order of magnitude smaller and more power efficient than the system fielded in 2002 and 2003. Early prototypes have also demonstrated a significant improvement in TNT sensitivity, and similar improvements are anticipated in RDX sensitivity during Q1 2005. Blind test results from 2003 confirm the radio frequency interference and piezo-electric ringing immunity of the Quantum Magnetics QR Confirmation Sensor (QRCS).

Barrall, G. A.; Arakawa, M.; Barabash, L. S.; Bobroff, S.; Chepin, J. F.; Derby, K. A.; Drew, A. J.; Ermolaev, K. V.; Huo, S.; Lathrop, D. K.; Steiger, M. J.; Stewart, S. H.; Turner, P. J.

2005-06-01

59

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

NASA Technical Reports Server (NTRS)

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

Murty, A. N.

1978-01-01

60

Kinetic approach to the damping of giant quadrupole resonances  

SciTech Connect

The effect of one- and two-body dissipation on the damping of giant quadrupole resonances is studied in a semiclassic approach solving a Vlasov equation with a collisional relaxation time. The latter is microscopically evaluated from the equilibration of a distorted momentum distribution in a kinetic approach. Important effects from energy and angle dependent nucleon-nucleon ({ital NN}) cross sections and from the time variation of Pauli blocking are stressed. Once these points are suitably treated, a good agreement with the experimental systematics is obtained from the use of a free {ital NN} cross section.

Bonasera, A.; Di Toro, M.; Gulminelli, F. (Istituto Nazionale di Fisica Nucleare, Corso Italia 57, 95129 Catania (Italy) Dipartimento di Fisica, Corso Italia 57, 95129 Catania (Italy) Dipartimento di Fisica, Via Celoria 16, 20133 Milano (Italy) Laboratorio Nazionale del Sud, Viale A. Doria, 95125 Catania (Italy))

1990-09-01

61

Pressure and temperature dependence of the chlorine NQR in caesium and sodium chlorates.  

PubMed

The (35)Cl nuclear quadrupole resonance (NQR) frequencies (nu(Q)) in caesium and sodium chlorates were measured as a function of temperature, from 77 to 300 K at different pressures up to 5.1 kbar, and the data were analysed to estimate the volume dependence of the electric field gradient (EFG), torsional frequency and also the contributions to the NQR frequency from static and dynamic effects. The variation of spin-lattice relaxation time with pressure at different temperatures was studied in the case of sodium chlorate and at room temperature in case of caesium chlorate. The pressure dependence of the spin-lattice relaxation time (T(1)) suggests that the relaxation is mainly due to the torsional motions. PMID:18324738

Ramesh, K P; Suresh, K S; Raghavendra Rao, C; Ramakrishna, J

2008-06-01

62

Application of an explosive detection device based on quadrupole resonance (QR) technology in aviation security  

Microsoft Academic Search

The Federal Aviation Administration has deployed Advanced Technology (AT) based explosive detection devices for screening checked baggage in US domestic airports. The paper addresses the application of quadrupole resonance (QR) technology to detect explosives in checked baggage in aviation security. This technology was deployed in combination with advanced X-ray by the US government. The paper focuses on the quadrupole resonance

Ed Rao; William J. Hughes

2001-01-01

63

Nuclear quadrupole resonance. Electronic structure and sterochemistry of halogenonaphthalenones  

SciTech Connect

The /sup 35/Cl NQR spectra of 2-chloro-, 2, 3-dihydro-2-bromo-2,3-dichloro-, and 2,2,3-trichloro-4-diphenyl-methylene-1(4H)-napthalenones (I-III) were studied. The experimental data are compared with the results from quantum-chemical calculations for the conformers of the molecules of (I-III) by the CNDO/2 method. The adequacy of the conformation description of systems (I-III) by the method using the /sup 35/Cl NQR frequencies was established by study of 1,2-dichloroacenaphthene and 2-chlorotetrahydropyran. It was established that compound (II) in the crystal exists in the form of the conformer with the bromine atom in the axial position. The possibilities of using an electrostatic model for the discussion of the conformations of the 2,3-dyhydro derivatives (II) and (III) with separate allowance for the geminal and vicinal environments of the chlorine probe atom are examined.

Romanenko, E.A.; Nesterenko, A.M.; Novikov, V.P.; Kolesnikov, V.T.

1987-11-01

64

Signal processing for improved explosives detection using quadrupole resonance  

NASA Astrophysics Data System (ADS)

Quadrupole resonance (QR) technology for explosives detection is of crucial importance in an increasing number of applications. For landmine detection, where the detection system cannot be adequately shielded, QR has proven to be highly effective if the QR sensor is not exposed to radio frequency interference (RFI). However, strong non-Gaussian RFI in the field is unavoidable, making RFI mitigation a critical part of the signal processing. In this paper, a statistical model of the non-Gaussian RFI is presented. The QR model is used within the context of an adaptive filtering methodology to mitigate RFI, and this approach is compared to other RFI mitigation techniques. Results obtained using both simulated and measured QR data are presented.

Tan, Yingyi; Tantum, Stacy L.; Collins, Leslie M.

2004-09-01

65

Collective resonances in metal nanoparticle arrays with dipole-quadrupole interactions  

NASA Astrophysics Data System (ADS)

Two-dimensional periodic arrays of metal dipole nanoparticles support excitation of narrow collective resonances, which can be used for enhanced light reflection or transmission and for sensing applications. With growing particle sizes, the width of collective dipole resonances is increased, approaching the width of localized surface plasmon resonance of a single particle. However, in systems with broad collective dipole resonances, much narrower resonances can be obtained due to higher multipole radiation coupling between particles. Here we developed a theoretical (semianalytical) approach for investigations of the collective (diffractive) coupling between dipole and quadrupole modes of isolated metal particles arranged in infinite or finite-size arrays. This approach is based on a solution of coupled dipole-quadrupole equations, where the dipole and quadrupole polarizabilities of individual particles are determined by Mie theory. The radiative quadrupole coupling between the particles is introduced by the full-wave quadrupole propagator. Extinction and scattering cross sections of nanoparticle arrays with dipole-quadrupole interactions are presented and discussed. The developed approach is applied for investigations of light transmission through two-dimensional hexagonal arrays of gold nanoparticles. It is shown that the quadrupole coupling can produce narrow collective resonances on the dipole background in the transmission spectra. Sensing properties of the quadrupole resonances are discussed.

Evlyukhin, Andrey B.; Reinhardt, Carsten; Zywietz, Urs; Chichkov, Boris N.

2012-06-01

66

Multiple-pulse NQR dynamics of spin systems with strong heteronuclear coupling  

NASA Astrophysics Data System (ADS)

The results are presented of a theoretical consideration of the nuclear quadrupole resonance (NQR) and spinspin relaxation for a paramagnetic body containing nuclei of two different sorts coupled by the strong homonuclear and heteronuclear dipoledipole interactions and influenced by an external multiple-pulse radiofrequency magnetic field acting only on nuclei of one sort. Kinetic equations were obtained giving the possibility of finding the time dependence of the magnetization of the body and the kinetic coefficients calculated as a function of the multiple-pulse field parameters. The possibilities of using the results in question for molecular structure and molecular dynamics investigations are briefly surveyed.

Furman, G. B.; Shaposhnikov, I. G.

1994-05-01

67

A general numerical analysis of time-domain NQR experiments.  

PubMed

We introduce a general numerical approach for solving the Liouville equation of an isolated quadrupolar nuclide that can be used to analyze the unitary dynamics of time-domain NQR experiments. A numerical treatment is necessitated by the dimensionality of the Liouville space, which precludes analytical, closed form solutions for I > 3/2. Accurate simulations of experimental nutation curves, forbidden transition intensities, powder and single crystal spectra, and off-resonance irradiation dynamics can be computed with this method. We also examine the validity of perturbative approximations where the signal intensity of a transition is proportional to the transition moment between the eigenstates of the system, thus providing a simple basis for determining selection rules. Our method allows us to calculate spectra for all values of the asymmetry parameter, eta, and sample orientations relative to the coil axis. We conclude by demonstrating the methodology for calculating the response of the quadrupole system to amplitude- and frequency-modulated pulses. PMID:16996760

Harel, Elad; Cho, Herman

2006-12-01

68

Electric quadrupole excitation in surface plasmon resonance of metallic composite nanohole arrays  

NASA Astrophysics Data System (ADS)

We present an experimental and theoretical study on the composite nanostructures composed of the LT-shaped metallic nanohole arrays. Multiple resonance transmission peaks are observed in the optical transmission spectra. By analyzing their electric field distributions on the interface, we infer the electric dipole and the electric quadrupole plasmonic resonances contribute to these transmission peaks. The electric quadrupole is a subradiant mode, which cannot be directly excited by the incident light. Here, we demonstrate that the surface plasmon polaritons can excite the electric quadrupole plasmonic resonance mode through the near-field interaction.

Wu, Shan; Liu, Jianqiang; Zhou, Lin; Wang, Qianjin; Zhang, Yi; Wang, Guodong; Zhu, Yongyuan

2011-10-01

69

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

70

Pulsed Spin Locking in Spin-1 NQR: Broadening Mechanisms  

NASA Astrophysics Data System (ADS)

Nuclear Quadrupole Resonance (NQR) is a branch of magnetic resonance physics that allows for the detection of spin I > 1/2 nuclei in crystalline and semi-crystalline materials. Through the application of a resonant radio frequency (rf) pulse, the nuclei's response is to create an oscillating magnetic moment at a frequency unique to the target substance. This creates the NQR signal, which is typically weak and rapidly decaying. The decay is due to the various line broadening mechanisms, the relative strengths of which are functions of the specific material, in addition to thermal relaxation processes. Through the application of a series of rf pulses the broadening mechanisms can be refocused, narrowing the linewidth and extending the signal in time. Three line broadening mechanisms are investigated to explain the NQR signal's linewidth and behavior. The first, electric field gradient (EFG) inhomogeneity, is due to variations in the local electric environment among the target nuclei, for instance from crystal imperfections. While EFG inhomogeneity can vary between samples of the same chemical composition and structure, the other broadening mechanisms of homonuclear and heteronuclear dipolar coupling are specific to this composition and structure. Simple analytical models are developed that explain the NQR signal response to pulse sequences by accounting for the behavior of each broadening mechanism. After a general theoretical introduction, a model of pairs of spin-1 nuclei is investigated, and the refocusing behaviors of EFG and homonuclear dipolar coupling are analyzed. This reveals the conditions where EFG is refocused but homonuclear dipolar coupling is not. In this case the resulting signal shows a rapid decay, the rate of which becomes a measure of interatomic distances. This occurs even in the more complex case of a powder sample with its many randomly oriented crystallites, under particular pulsing conditions. Many target NQR compounds are rich in hydrogen, and therefore might have a significant heteronuclear dipolar coupling component. To incorporate this, a second model is developed composed of two different nuclear species, one spin 1 the other spin 1/2, although the work can be extended to additional spin species. This model reveals that heteronuclear dipolar coupling for this system behaves just like EFG broadening under spin locking, and that the strong homonuclear response is still observable. The experimental results closely match theoretical predictions, and the conclusions greatly expand the number of target substances that are suitable for this measurement technique of homonuclear dipolar coupling. The combined results explain why certain pulse sequences perform better than others for substance detection: it is because of the relative strengths of the line broadening mechanisms. Therefore the ability to measure homonuclear dipolar coupling's contribution to the linewidth is useful not only for material characterization, but also for substance detection. By explaining the conditions that reveal homonuclear coupling, we make it possible to measure the relative broadening strengths, increasing the efficiency of NQR in these roles.

Malone, Michael W.

71

NQR Line Broadening Due to Crystal Lattice Imperfections and Its Relationship to Shock Sensitivity  

NASA Astrophysics Data System (ADS)

The hydrodynamic hot spot model is used to explain the difference between shock sensitive and shock insensitive explosives. Among the major factors that influence the shock sensitivity of energetic compounds are the quality and particle size of the energetic crystals used to formulate the cast plastic bonded explosive. As do all energetic compounds, RDX and HMX exhibit internal crystal defects the magnitude and type of which depend on the manufacturing process used to synthesize and re-crystallize the energetic compound. Nuclear Quadrupole Resonance (NQR) spectroscopy was used to determine the crystal quality of RDX, HMX and CL-20 obtained from various manufacturers. The NQR experimental results are discussed. Cast plastic bonded explosives were made using the RDX and HMX obtained from the various manufacturers and subsequently subjected to the NOL large-scale gap test (LSGT). The results of the LSGT are discussed and correlated with the NQR results. A relationship between the crystal defect density and shock initiation pressure of the plastic bonded explosive is developed and discussed.

Caulder, S. M.; Buess, M. L.; Garroway, A. N.; Miller, P. J.

2004-07-01

72

Quality control and health monitoring of aerospace composites via quadrupole resonance  

Microsoft Academic Search

Techniques for quality control and health monitoring of aerospace composite structures must be reliable, nonintrusive and preferably, non-contacting. Quadrupole resonance (QR) spectroscopy can fill this need. Previously, we have demonstrated that Quadrupole Resonance can be used for nondestructive inspection of polymeric fiber-reinforced composites, which can be exploited for both in-service inspection and on-going structural health monitoring.1-6 In this paper we

Catherine Ward; Stephanie A. Vierkoetter

2005-01-01

73

14N quadrupole resonance and 1H T1 dispersion in the explosive RDX.  

PubMed

The explosive hexahydro-1,3,5-trinitro-s-triazine (CH2-N-NO2)3, commonly known as RDX, has been studied by 14N NQR and 1H NMR. NQR frequencies and relaxation times for the three ?+ and ?- lines of the ring 14N nuclei have been measured over the temperature range 230-330 K. The 1H NMR T1 dispersion has been measured for magnetic fields corresponding to the 1H NMR frequency range of 0-5.4 M Hz. The results have been interpreted as due to hindered rotation of the NO2 group about the N-NO2 bond with an activation energy close to 92 kJ mol(-1). Three dips in the 1H NMR dispersion near 120, 390 and 510 kHz are assigned to the ?0, ?- and ?+ transitions of the 14NO2 group. The temperature dependence of the inverse line-width parameters T2? of the three ?+ and ?- ring nitrogen transitions between 230 and 320 K can be explained by a distribution in the torsional oscillational amplitudes of the NO2 group about the N-NO2 bond at crystal defects whose values are consistent with the latter being mainly edge dislocations or impurities in the samples studied. Above 310 K, the 14N line widths are dominated by the rapid decrease in the spin-spin relaxation time T2 due to hindered rotation of the NO2 group. A consequence of this is that above this temperature, the 1H T1 values at the quadrupole dips are dominated by the spin mixing time between the 1H Zeeman levels and the combined 1H and 14N spin-spin levels. PMID:21978662

Smith, John A S; Blanz, Martin; Rayner, Timothy J; Rowe, Michael D; Bedford, Simon; Althoefer, Kaspar

2011-12-01

74

Experimental study of the structure of chalcogenide glassy semiconductors in three-component systems of Ge-As-Se and As-Sb-Se by means of NQR and EPR spectroscopy  

NASA Astrophysics Data System (ADS)

The structure of chalcogenide glassy semiconductors in three-component systems of Ge-As-Se and As-Sb-Se has been studied by means of both NQR (nuclear quadrupole resonance) and EPR (electron paramagnetic resonance) spectroscopy. It is investigated that in the glasses of both systems the value of the electric field gradient at the resonating nuclei grows with increasing concentration of the clusters As2Se3 and Sb2Se3, thereby increasing the NQR resonance frequencies. It appears that for the Ge-As-Se system the structural transition from a two-dimensional to three-dimensional structure occurs at average coordination number = 2.45. The EPR spectral parameters of glasses depend on the composition, the average coordination number and the temperature, and these are discussed. The effect of "ageing" for CGS (chalcogenide glassy semiconductors) of As-Sb-Se system due to partial crystallization of the sample is observed from the EPR spectra.

Bolebrukh, Olga N.; Sinyavsky, Nikolay Ya.; Korneva, Irina P.; Dobosz, Bernadeta; Ostafin, Michal; Nogaj, Boleslaw; Krzyminiewski, Ryszard

2013-12-01

75

Microscopic properties of the heavy-fermion superconductor PuCoIn5 explored by nuclear quadrupole resonance  

NASA Astrophysics Data System (ADS)

We report 115In nuclear quadrupolar resonance (NQR) measurements on the heavy-fermion superconductor PuCoIn5, in the temperature range 0.29K ? T ? 75K. The NQR parameters for the two crystallographically inequivalent In sites are determined, and their temperature dependence is investigated. A linear shift of the quadrupolar frequency with lowering temperature below the critical value Tc is revealed, in agreement with the prediction for composite pairing. The nuclear spin-lattice relaxation rate T1-1(T) clearly signals a superconducting (SC) phase transition at Tc ? 2.3 K, with strong spin fluctuations, mostly in-plane, dominating the relaxation process in the normal state near to Tc. Analysis of the T1-1 data in the SC state suggests that PuCoIn5 is a strong-coupling d-wave superconductor.

Koutroulakis, G.; Yasuoka, H.; Chudo, H.; Tobash, P. H.; Mitchell, J. N.; Bauer, E. D.; Thompson, J. D.

2014-05-01

76

Structural study of selected polyhalogenated benzimidazoles (protein kinase CK2 inhibitors) by nuclear quadrupole double resonance, X-ray, and density functional theory.  

PubMed

Protein kinase CK2 inhibitors, polyhalogenated benzimidazoles, have been studied experimentally in solid state by NMR-NQR double resonance and X-ray and theoretically by the density functional theory (DFT). Six resonance frequencies on (14)N have been detected and assigned to particular nitrogen sites in each polyhalogenated benzimidazole molecule. The effects of prototropic annular tautomerism and polymorphism related to stable cluster formation due to intermolecular hydrogen bonding interactions on the (14)N NQR parameters have been analyzed within the DFT and AIM (atoms in molecules) formalism. The studies suggest that all polyhalogenobenzimidazoles are isostructural and can exhibit polymorphism and that (14)N NQR is very sensitive to hydrogen bondings but less sensitive to the specific arrangement of the hydrogen bonded molecules. NQDR and DFT results suggest the presence of the prototropic annular tautomerism 50:50, which is in a good agreement with the X-ray and (1)H NMR data. PMID:20055520

Latosi?ska, J N; Latosi?ska, M; Seliger, J; Zagar, V; Maurin, J K; Orzeszko, A; Kazimierczuk, Z

2010-01-14

77

Frequencies of nuclear resonances for copper and electronic wave function of antiferromagnetic La2CuO4  

Microsoft Academic Search

Calculated values of the frequencies of nuclear magnetic and quadrupole resonances (for65Cuv(NMR) = 107 MHz, v(NQR) = 32 MHz) are close to the experimental values (100 MHz and 29.5 MHz). This coincidence is a reliable test of the obtained electronic wave function.

V. V. Flambaum; O. P. Sushkov

1990-01-01

78

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

79

On the coupling of the giant multipole resonances to the surface quadrupole oscillations of nuclei  

Microsoft Academic Search

Within the framework of the hydrodynamic model the exact coupling constants of the coupling of the giant multipole resonances to the surface quadrupole oscillations of nuclei are derived. The differences to former variational calculations are discussed. It is found that the coupling constants for the terms linear in the surface variables are almost the same whereas the coupling constants for

H. Stock; H. Arenhoevel

1968-01-01

80

Noble gas detection using resonance ionization spectroscopy and a quadrupole mass spectrometer  

Microsoft Academic Search

The technique of Resonance Ionization Spectroscopy (RIS) is being extended to develop a means for counting individual atoms of a selected isotope of a noble gas. In this method, lasers are used for RIS to obtain atomic species (Z) selectivity and a small quadrupole mass spectrometer provides isotopic (A) selectivity. A progress report on the objective of counting each atom

C. H. Chen; G. S. Hurst

1983-01-01

81

Ultrahigh refractive index sensing performance of plasmonic quadrupole resonances in gold nanoparticles  

PubMed Central

The refractive index sensing properties of plasmonic resonances in gold nanoparticles (nanorods and nanobipyramids) are investigated through numerical simulations. We find that the quadruple resonance in both nanoparticles shows much higher sensing figure of merit (FOM) than its dipolar counterpart, which is attributed mainly to the reduction in resonance linewidth. More importantly, our results predict that at the same sensing wavelength, the sensing FOM of the quadrupole mode can be significantly boosted from 3.9 for gold nanorods to 7.4 for gold nanobipyramids due to the geometry-dependent resonance linewidth, revealing a useful strategy for optimizing the sensing performance of metal nanoparticles.

2014-01-01

82

Ultrahigh refractive index sensing performance of plasmonic quadrupole resonances in gold nanoparticles  

NASA Astrophysics Data System (ADS)

The refractive index sensing properties of plasmonic resonances in gold nanoparticles (nanorods and nanobipyramids) are investigated through numerical simulations. We find that the quadruple resonance in both nanoparticles shows much higher sensing figure of merit (FOM) than its dipolar counterpart, which is attributed mainly to the reduction in resonance linewidth. More importantly, our results predict that at the same sensing wavelength, the sensing FOM of the quadrupole mode can be significantly boosted from 3.9 for gold nanorods to 7.4 for gold nanobipyramids due to the geometry-dependent resonance linewidth, revealing a useful strategy for optimizing the sensing performance of metal nanoparticles.

Yong, Zehui; Lei, Dang Yuan; Lam, Chi Hang; Wang, Yu

2014-04-01

83

Observation of electric quadrupole spin resonance of Ho3+ impurity ions in synthetic forsterite  

NASA Astrophysics Data System (ADS)

The anomalous dependence of the electron paramagnetic resonance (EPR) line shape on the microwave power in the resonator has been found when studying the continuous-wave EPR spectra of impurity holmium ions in synthetic forsterite on an ELEXSYS E 580 EPR spectrometer. The power-threshold transition from the conventional lines being the derivatives of the spectral line contours to the spectral line contours themselves has been observed as the power increased. The properties of the anomalous EPR lines are qualitatively explained assuming that the resonance electric quadrupole transitions take place between the electron spin levels.

Tarasov, V. F.; Zaripov, R. B.; Solovarov, N. K.; Sukhanov, A. A.; Zharikov, E. V.

2011-05-01

84

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

SciTech Connect

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 system involves pulsed nuclear double resonance detection; and alterative is to observe the quadrupolar splitting of the NMR signal. Choices to be made in the measurement and mapping techniques are discussed. The well-known perturbation of the homogenous stress field in the neighborhood of a borehole is shown to be advantageous from the point of view of obtaining directional information on the stress. Construction and operation of a borehole stress sensor are considered. The NQR technique seems feasible for measuring the magnitude and direction of underground stress with a resolution of about 25 psi, or 2.5% at 1000 psi. Downhole instrumentation suitable for in-situ determinations of stress appears within the state of the art. Additional tasks required on the project are identified.

Schempp, E.; Hirschfeld, T.; Klainer, S.

1980-12-01

85

Noble gas detection using resonance ionization spectroscopy and a quadrupole mass spectrometer  

SciTech Connect

The technique of Resonance Ionization Spectroscopy (RIS) is being extended to develop a means for counting individual atoms of a selected isotope of a noble gas. In this method, lasers are used for RIS to obtain atomic species (Z) selectivity and a small quadrupole mass spectrometer provides isotopic (A) selectivity. A progress report on the objective of counting each atom of a particular isotope of a noble gas is given. 11 references, 4 figures.

Chen, C.H.; Hurst, G.S.

1983-01-01

86

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

DOEpatents

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

Fan, N.Q.; Clarke, J.

1993-10-19

87

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

88

Two-dimensional NQR using ultra-broadband electronics.  

PubMed

We have recently developed an ultra-broadband instrument that can effectively excite and detect NMR and NQR signals over a wide frequency range. Our current system operates between 100 kHz and 3.2 MHz using an un-tuned sample coil. The major benefits of this instrument compared to conventional NQR/NMR systems include increased robustness, ease of use (in particular for multi-frequency experiments), and elimination of the need for tuning adjustments in the hardware. Here we describe its use for performing two-dimensional (2D) scans, which allow improved interpretation of complex NQR spectra by detecting the connected resonances. Our method relies on population transfers between the three energy levels of spin-1 nuclei (such as (14)N) by using multi-frequency excitation and a single RF coil. Experimental results on pure samples and mixtures are also presented. PMID:24495675

Mandal, S; Song, Y-Q

2014-03-01

89

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

2012-03-01

90

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

91

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

NASA Astrophysics Data System (ADS)

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.; Urin, M. H.

2012-09-01

92

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

93

Magnetic correlations in La(2-x)Sr(x)CuO4 from NQR relaxation and specific heat  

NASA Technical Reports Server (NTRS)

La-139 and Cu-63 Nuclear Quadrupole Resonance (NQR) relaxation measurements in La(2-x)Sr(x)CuO4 for x ranging from 0 up to 0.3, with particular emphasis on the effect of doping on the Cu(2+) magnetic correlations and dynamics, are reviewed. In the low doping limit, x less than or equal to 0.05, the results can be interpreted consistently in terms of a simple phenomenological 'two-fluids' model whereby the effect of thermally-activated mobile O(2p) holes is the one of disrupting locally the Cu(2+) spin correlations. For x greater than or equal to 0.1, the results indicate the onset, as T approaches T(sub c)(+), of a strong coupling between Cu(2+) spins and the Fermi liquid of O(2p) holes leading to the apparent disappearance of localized Cu(2+) moment in connection with the opening of a superconducting gap.

Borsa, F.; Rigamonti, A.

1991-01-01

94

Density functional calculations of 14N and 11B NQR parameters in the H-capped (6,0) and (4,4) single-walled BN nanotubes  

NASA Astrophysics Data System (ADS)

Density functional theory (DFT) calculations were performed to calculate nitrogen-14 and boron-11 nuclear quadrupole resonance (NQR) spectroscopy parameters in the representative considered models of zigzag and armchair boron nitride nanotubes (BNNTs) for the first time. The considered models consisting of 1 nm length of H-capped (6,0) and (4,4) single-walled BNNT were first allowed to fully relax and then the NQR calculations were performed on the geometrically optimized models. The evaluated nuclear quadrupole coupling constants and asymmetry parameters for the mentioned nuclei reveal that the considered models can be divided into four layers of nuclei with an equivalent electrostatic environment where those nuclei at the ends of tubes have a very strong electrostatic environment compared to the other nuclei along the length of tubes. Those nuclei at the center of the tube length also have an equivalent electrostatic environment. The calculations were performed based on the B3LYP DFT method and 6-311G** and 6-311++G** standard basis sets using the Gaussian 98 package of program.

Mirzaei, Mahmoud; Hadipour, Nasser L.

2008-02-01

95

^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

96

Magnetic and quadrupole resonance studies of high-T(c) cuprates  

NASA Astrophysics Data System (ADS)

The 63,65Cu NQR spectrum has been measured as a function of Pr doping (x) in the material Y1-xPrxBa 2Cu3O7-delta (x = 0--1.0) at 300K. The chain copper, Cu(1), spectrum showed anomalous peaks as the Pr content increased, while the quadrupolar resonance frequency, nuQ, decreased with x. Point dipole electric field gradient (EFG) simulations performed for all Cu sites point towards the occupation of a new oxygen site, O(5), as the cause for the newly observed peaks in the Cu(1) spectrum. Oxygen deficiency simulations were also performed and cannot account for the anomalous peak seen in the Cu(1) spectrum. 17O NMR at 9T, 13T, 23T, 37T, and 42T has also been measured in NdBa2Cu3O7-delta for both apical and planar oxygen sites. The spin Knight shift for the planar oxygen sites, O(2,3), is smaller than its counterpart in YBCO. We speculate this maybe due to less superconducting carriers in NdBCO. The spin Knight shift of the apical oxygen, O(4), sites is far larger than the value reported in the parent compound, YBCO, and we speculate this may be due to enhanced polarization on the O(4) site, though we are unsure why. The spin-lattice relaxation rate, 1/T1, has also been measured as a function of temperature and is roughly two orders faster than those of YBCO. Moreover, 1/T1 shows a peak at 20K at 9T that shifts to higher temperatures as the field is increased, along with the suppression of this peak with increasing field. The relaxation mechanism in this system has been attributed to the fluctuations of the Nd-moments on the rare earth (RE) site and the enhanced Cu-Cu antiferromagnetic fluctuations. The temperature dependence of the spin-spin relaxation rate, 1/T 2 has been measured at low fields. The onset of vortex "freezing" is observed at low temperatures, while at higher temperatures, the vortices are in the liquid state. The vortex freezing occurs at a lower temperature than in YBCO, but is consistent with samples that have more defects. One possible reason for the increased defects could be Nd-substituted Ba sites, which act as point defects and pinning centers.

Abdelrazek, Margie Mahmoud

97

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

98

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

99

Splitting of the giant monopole and quadrupole resonances in 154Sm  

NASA Astrophysics Data System (ADS)

Strength functions for the isoscalar giant monopole and quadrupole resonances in 154Sm have been measured with inelastic scattering of 240 MeV ? particles at small angles. The E0 strength distribution containing (104+15-20)% of the energy-weighted sum rule (EWSR) is consistent with two peaks at Ex=12.1+/-0.4 MeV and 15.5+/-0.3 MeV containing (36+/-10)% and (68+/-9)% of the EWSR and the E2 strength distribution containing (103+18-20)% of the EWSR is consistent with three peaks at Ex=11.3+/-0.2 MeV, 14.5+/-0.5 MeV, and 17.5+/-0.5 MeV containing (44+/-7)%, (44+/-8)%, and (15+/-8)%, respectively, of the EWSR.

Youngblood, D. H.; Lui, Y.-W.; Clark, H. L.

1999-12-01

100

New method for precise determination of the isovector giant quadrupole resonances in nuclei.  

PubMed

The intense, nearly monoenergetic, 100% polarized ?-ray beams available at the HI?S facility, along with the realization that the E1-E2 interference term that appears in the Compton scattering polarization observable has opposite signs in the forward and backward angles, make it possible to obtain an order-of-magnitude improvement in the determination of the parameters of the isovector giant quadrupole resonance (IVGQR). Accurate IVGQR parameters will lead to a more detailed knowledge of the symmetry energy in the nuclear equation of state which is important for understanding nuclear matter under extreme conditions such as those present in neutron stars. Our new method is demonstrated for the case of (209)Bi. PMID:22182024

Henshaw, S S; Ahmed, M W; Feldman, G; Nathan, A M; Weller, H R

2011-11-25

101

Ferromagnetic Quantum Critical Fluctuations and Anomalous Coexistence of Ferromagnetism and Superconductivity in UCoGe Revealed by Co-NMR and NQR Studies  

NASA Astrophysics Data System (ADS)

Co nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) studies were carried out for the recently discovered UCoGe, in which the ferromagnetic and superconducting (SC) transitions are reported to occur at TCurie 3 K and TS 0.8 K [Huy et al.: Phys. Rev. Lett. 99 (2007) 067006], in order to investigate the coexistence of ferromagnetism and superconductivity as well as the normal-state and SC properties from a microscopic point of view. From the nuclear spin-lattice relaxation rate 1/T1 and Knight-shift measurements, we confirm that ferromagnetic fluctuations that possess a quantum critical character are present above TCurie and also the occurrence of a ferromagnetic transition at 2.5 K in our polycrystalline sample. The magnetic fluctuations in the normal state show that UCoGe is an itinerant ferromagnet similar to ZrZn2 and YCo2. The onset SC transition is identified at TS 0.7 K, below which 1/T1 arising from 30% of the volume fraction starts to decrease due to the opening of the SC gap. This component of 1/T1, which follows a T3 dependence in the temperature range 0.3-0.1 K, coexists with the magnetic components of 1/T1 showing a \\sqrt{T} dependence below TS. From the NQR measurements in the SC state, we suggest that the self-induced vortex state is realized in UCoGe.

Ohta, Tetsuya; Nakai, Yusuke; Ihara, Yoshihiko; Ishida, Kenji; Deguchi, Kazuhiko; Sato, Noriaki K.; Satoh, Isamu

2008-02-01

102

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

103

A novel shoe scanner using an open-access quadrupole resonance and metal sensor  

NASA Astrophysics Data System (ADS)

Airport security and efficiency are both compromised by the process of requiring passengers to remove their shoe. A novel shoe scanner developed at the GE Security San Diego Center of Excellence uses both Quadrupole Resonance (QR) and configuration-sensitive metal detection to identify threats hidden in shoes. The shoe scanner was developed with an open-access chassis and scanning chamber that allows passengers to stand in the system in a natural position during the scanning process. More traditional magnetic resonance systems are closed or partially closed and cannot be used for screening personnel because the scanning chambers confine the object in question. The shoe scanner's novelty lies in a particular chassis geometry that allows both QR and metal screening. The resulting scanning system achieves the same level of performance as a more confining system. The shoe scanner is small enough to allow integration with other sensors such as the GE Itemizer FX TM trace detection system. In fact, the first application of the novel shoe scanner is expected to be as a component in a multi-sensor verification and security system known as the Secure Registered Traveler (SRT) Kiosk. The SRT kiosk is designed to be used as part of the TSA's Registered Traveler Program.

Crowley, C.; Petrov, T.; Mitchell, O.; Shelby, R.; Ficke, L.; Kumar, S.; Prado, P.

2007-05-01

104

Global investigation of the fine structure of the isoscalar giant quadrupole resonance  

SciTech Connect

Fine structure in the region of the isoscalar giant quadrupole resonance (ISGQR) in {sup 58}Ni, {sup 89}Y, {sup 90}Zr, {sup 120}Sn, {sup 166}Er, and {sup 208}Pb has been observed in high-energy-resolution ({delta}E{sub 1/2}{approx_equal}35-50 keV) inelastic proton scattering measurements at E{sub 0}=200 MeV at iThemba LABS. Calculations of the corresponding quadrupole excitation strength functions performed within models based on the random-phase approximation (RPA) reveal similar fine structure when the mixing of one-particle one-hole states with two-particle two-hole states is taken into account. A detailed comparison of the experimental data is made with results from the quasiparticle-phonon model (QPM) and the extended time-dependent Hartree-Fock (ETDHF) method. For {sup 208}Pb, additional theoretical results from second RPA and the extended theory of finite Fermi systems (ETFFS) are discussed. A continuous wavelet analysis of the experimental and the calculated spectra is used to extract dominant scales characterizing the fine structure. Although the calculations agree with qualitative features of these scales, considerable differences are found between the model and experimental results and amongst different models. Within the framework of the QPM and ETDHF calculations it is possible to decompose the model spaces into subspaces approximately corresponding to different damping mechanisms. It is demonstrated that characteristic scales mainly arise from the collective coupling of the ISGQR to low-energy surface vibrations.

Shevchenko, A.; Burda, O.; Kalmykov, Y.; Neumann-Cosel, P. von; Ponomarev, V. Yu.; Richter, A.; Wambach, J. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, D-64289, Darmstadt (Germany); Carter, J.; Sideras-Haddad, E. [School of Physics, University of the Witwatersrand, PO Wits, Johannesburg 2050 (South Africa); Cooper, G. R. J. [School of Earth Sciences, University of the Witwatersrand, PO Wits, Johannesburg 2050 (South Africa); Fearick, R. W. [Department of Physics, University of Cape Town, Rondebosch 7700 (South Africa); Foertsch, S. V.; Lawrie, J. J.; Neveling, R.; Smit, F. D. [iThemba LABS, P. O. Box 722, Somerset West 7129 (South Africa); Fujita, H. [School of Physics, University of the Witwatersrand, PO Wits, Johannesburg 2050 (South Africa); Department of Physics, Osaka University, Toyonaka, Osaka 560-0043 (Japan); Fujita, Y. [Department of Physics, Osaka University, Toyonaka, Osaka 560-0043 (Japan); Lacroix, D. [GANIL, CEA and IN2P3, Boite Postale 5027, F-14076 Caen Cedex (France); Laboratoire de Physique Corpusculaire, ENSICAEN and Universite de Caen, IN2P3-CNRS, Blvd du Marechal Juin, F-14050 Caen (France)

2009-04-15

105

Unconventional Pairing States in Heavy-Fermion Superconductors Studied by the NQR/NMR Experiments  

NASA Astrophysics Data System (ADS)

We review the studies on the unconventional superconducting pairing states and their relevance with magnetism in the f-electron derived heavy-fermion (HF) systems by means of nuclear-magnetic-resonance (NMR) and nuclear-quadrupole-resonance (NQR). These studies have unraveled a rich variety of the phenomena in the ground state of HF systems. In this article, we address an intimate relationship between the onset of strong-coupling superconductivity (SC) and critical magnetic fluctuations emerging in the vicinity of quantum critical point (QCP). Furthermore, we focus on the novel phase diagram of the HF antiferromagnet CeRhIn5 under pressure which is characterized by the tetracritical point separating the pure antiferromagnetism (AFM) phase, the AFM+SC uniformly coexisting phase, and the paramagnetic SC phase. A comparison is also presented on the AFM+SC uniformly coexisting phase in high-temperature superconductors as the function of carrier doping. As a consequence, we raise a question; Do we need a bosonic glue to pair electrons in these superconductors? Finally, we address a possible origin of the novel SC in the itinerant ferromagnet UGe2, which is mediated by ferromagnetic spin-density fluctuations relevant with the first-order transition inside the ferromagnetic states.

Kitaoka, Yoshio; Mukuda, Hidekazu; Yashima, Mitsuharu; Harada, Atsushi

2007-05-01

106

Orbital electronegativities and the determination of s and d hybridization in various halides from nuclear quadrupole resonance frequencies  

Microsoft Academic Search

The use of Orbital Electronegativities in the interpretation of NQR results for various halides is discussed, and an attempt to determine the amount of d hybridization in s and p bonding is made. The ionic characters are assessed.

M. A. Whitehead; H. H. Jaff

1963-01-01

107

Copper Nqr and NMR Study of Metal-Substituted Yttrium BARIUM(2) COPPER(3) OXYGEN(7) and Yttrium BARIUM(2) COPPER(4) OXYGEN(8)  

NASA Astrophysics Data System (ADS)

Pulsed nuclear quadrupole resonance (NQR) and nuclear magnetic resonance (NMR) have been used to investigate the effect of metal-substitution for copper in YBa_2Cu_3O_7 (YBCO123) and YBa_2Cu_4O_8 (YBCO124). Among many metal substitutions, Zn has an especially dramatic effect in suppressing the superconducting temperature T_{c}, and hence superconductivity. More interesting is that Zn and Fe have the same T_{c} suppression effect in YBCO124. This study focuses on the Zn substitutions in YBCO123 and Zn, Fe, and Co substitutions in YBCO124. In Zn doped YBCO123, Cu(2), plane site, NQR spectra and the frequency dependence of the spin-lattice relaxation rates have been measured over a temperature range from 77 K to 300 K to study the correlation of the suppression of the relaxation rate with the distance between the probe Cu nuclei and the impurity. It is found that the relaxation rate is insensitive to the variation of the NQR resonance frequency. However, by comparing the results of the Zn doped YBCO124 with those of YBCO123, it can be concluded that the suppression of the relaxation rate for both YBCO compounds in the normal state is caused by destruction of short-range antiferromagnetic correlation with substitution of nonmagnetic ion Zn on the Cu(2) sites. NQR and NMR measurements were carried out on both Cu(2), plane, and Cu(1), chain sites, for various concentrations of Zn, Fe, and Co dopants in YBCO124 over a temperature range from 77 K to 300 K. A strong correlation of the enhancement of Cu(2) spin lattice relaxation rate and suppression of superconductivity by impurities was found. The temperature dependence of the Cu(2) NMR linewidth exhibits a strong RKKY type exchange interaction below 225 K for Zn and Fe doped samples, which indicates the formation of the local magnetic moment. The enhancement of the relaxation rate is caused by the local magnetic moment Fe^ {+3} ion and the moments on Cu(2) neighbors when Zn^{+2} is substituted on Cu(2). This study gives us a clear picture of the spin pseudogap behavior in the high temperature superconductor cuprates. It also suggests that the magnetic moment on the CuO_2 plane may relate to the suppression of T_{c} in metal-substituted YBCO124.

Cheng, Show-Jye

108

Nuclear quadrupole double resonance spectrometer with magnetic property measurement system direct current superconducting quantum interference device detector and automatic tuning  

NASA Astrophysics Data System (ADS)

A new nuclear quadrupole double resonance spectrometer based on a commercial superconducting quantum interference device (SQUID) setup (a Magnetic Property Measurement System (MPMS) from Quantum Design) is described. The experiment involves the indirect detection of pure quadrupole resonances (PQR) of a dilute spin system via the direct SQUID detected NMR of an abundant spin system. The experiment is conducted at low (3-20 K) temperatures and the magnetic field is cycled between a high (5.5 T) polarizing field, to an intermediate (0.1 T) detection field, to zero field where the sample is irradiated with a modulated search RF and back to the detection field. Loss of the NMR signal indicates the detection of a PQR. The RF circuit used for both the NMR and zero field irradiation is digitally controlled. Use of the External Device Control allows for the complete automation of the system. Test measurements on diphenyl ether are in good agreement with previously reported results. Pure 17O quadrupole resonances were detected for spin systems with concentrations as low as 120 ?M.

Shroyer, Mark H.; Day, Edmund P.

2011-05-01

109

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

110

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

111

Sum-frequency generation via a resonant quadrupole transition in sodium  

Microsoft Academic Search

We show that second-order nonlinear optical processes such as sum and difference generation can be observed in isotropic media, despite the fact that such processes are forbidden in the electric-dipole approximation. A theoretical treatment of quadrupole sum- and difference-frequency generation is given, which includes the effects of spin-orbit and Zeeman splittings. The quadrupole nonlinear susceptibility is evaluated and expressions for

Donald S. Bethune; Robert W. Smith; Y. R. Shen

1978-01-01

112

Conformations and intermolecular interactions pattern in solid chloroxylenol and triclosan (API of anti-infective agents and drugs). A (35) Cl NQR, (1) H-(14) ?N NQDR, X-ray and DFT/QTAIM study.  

PubMed

Two antibacterial and antifungal agents, chloroxylenol (4-chloro-3,5-dimethyl-phenol) and triclosan (5-chloro-2-(2',4'-dichlorophenoxy)-phenol), were studied experimentally in solid state with an X-ray, (35) Cl-nuclear quadrupole resonance (NQR) and (17) O-nuclear quadrupole double resonance (NQDR) spectroscopies and, theoretically, with the density functional theory/quantum theory of atoms in molecules (DFT/QTAIM). The crystallographic structure of triclosan, which crystallises in space group P3(1) with one molecule in the asymmetric unit [a?=?12.64100(10), b?=?12.64100(10), c = 6.71630(10) ], was solved with an X-ray and refined to a final R-factor of 2.81% at room temperature. The NQR frequencies of (35) Cl and (17) O were detected with the help of the density functional theory (DFT) assigned to particular chlorine and oxygen sites in the molecules of both compounds. The NQR frequencies at (35) Cl sites in chloroxylenol and triclosan were found to be more differentiated than frequencies at the (17) O site. The former better describes the substituent withdrawing effects connected to ?-electron delocalization within the benzene rings and the influence of temperature; whereas, those at the (17) O site provide more information on O-H bond and intermolecular interactions pattern. The conformation adopted by diphenyl ether of triclosan in solid state was found to be typical of diphenyl ethers, but the opposite to those adopted when it was bound to different inhibitors. According to an X-ray study, temperature had no effect on the conformation of the diphenyl ring of triclosan, which was the same at 90?K and at room temperature (RT). The scattering of NQR frequencies reproduced by the DFT under assumption of the X-ray data at 90?K and RT is found to be a good indicator of the quality of resolution of the crystallographic structure. Copyright 2012 John Wiley & Sons, Ltd. PMID:22354770

Latosi?ska, J N; Latosi?ska, M; Tomczak, M A; Seliger, J; Zagar, V; Maurin, J K

2012-02-21

113

D Squids as Radiofrequency Amplifiers and Application to the Detection of Nuclear Quadrupole Resonance  

NASA Astrophysics Data System (ADS)

The high sensitivity of dc SQUID amplifiers is extended to the radio-frequency range. We perform a detailed investigation of the dynamic input impedance of tightly coupled dc SQUIDs and of the influence of parasitic capacitance between the SQUID and the input circuit on the SQUID characteristics. The reactive part of the dynamic input impedance is found to be determined by the inductive coupling, whereas the resistive part is found to be dominated by capacitive feedback. We also discuss the optimization of the input circuits for both tuned and untuned amplifiers and derive expressions for the optimum source resistance, gain and noise temperature for a given frequency, input coil and coupling. The performance of the amplifiers designed according to these prescriptions is measured. The gain of an untuned amplifier operated at 100 MHz at 4.2K is 16.5 (+OR-) 0.5dB with a noise temperature of 3.8 (+OR-) 0.9K; at 1.5K the gain increases to 19.5 (+OR-) 0.5dB while the noise temperature decreases to 0.9 (+OR-) 0.4K. A tuned amplifier operated at 93 MHz and 4.2K has a gain of 18.6 (+OR-) 0.5dB and a noise temperature of 1.7 (+OR-) 0.5K. These results are in good agreement with predicted values. The usefulness of these sensitive amplifiers for the detection of magnetic resonance is demonstrated. A SQUID system for pulsed nuclear quadrupole resonance at about 30 MHz is developed. At a bath temperature of 4.2K, a total system noise temperature of 6 (+OR-) 1K is achieved, with a quality factor Q of 2,500. A novel Q-spoiler, consisting of an array of Josephson tunnel junctions, reduces the ring-down time of the pick-up circuit after each pulse. The minimum number of nuclear Bohr magnetons observable after a single pulse is about 2 x 10('16) in a bandwidth of 10 kHz. Finally the low-noise SQUID amplifiers make it possible to use a novel technique for observing magnetic resonance in the absence of an externally applied radio-frequency field, by measuring the spectral density for the Nyquist noise current in a tuned circuit coupled to the sample. In thermal equilibrium, a dip is observed in the spectral density at the spin resonant frequency. For zero spin polarization, on the other hand, a bump in the spectral density is observed. This bump is due to temperature-independent fluctuations in the magnetization, and represents spontaneous emission from the spins into the circuit.

Hilbert, Claude

114

FPGA based pulsed NQR spectrometer  

NASA Astrophysics Data System (ADS)

An NQR spectrometer for the frequency range of 1 MHz to 5 MHZ has been designed constructed and tested using an FPGA module. Consisting of four modules viz. Transmitter, Probe, Receiver and computer controlled (FPGA & Software) module containing frequency synthesizer, pulse programmer, mixer, detection and display, the instrument is capable of exciting nuclei with a power of 200W and can detect signal of a few microvolts in strength. 14N signal from NaNO2 has been observed with the expected signal strength.

Hemnani, Preeti; Rajarajan, A. K.; Joshi, Gopal; Motiwala, Paresh D.; Ravindranath, S. V. G.

2014-04-01

115

35-Cl nuclear quadrupole resonance spectra in diazepam and its 1:1 complex with chloral hydrate  

NASA Astrophysics Data System (ADS)

The 35-Cl NQR spectra of diazepam and some of its related compounds are reported; they yield information about the hydrogen bonded complex that diazepam forms with chloral hydrate. The results reflect large changes in electron distribution at the CCl 3 group while the diazepam chlorine at the 7 position remains almost unaffected.

Brisson, Colette; Durand, Marcel; Jugie, Grard; Pasdeloup, Maurice

1980-11-01

116

Electronic properties of Y-Ba-Cu-O superconductors as seen by Cu and O NMR/NQR  

NASA Technical Reports Server (NTRS)

Nuclear Magnetic Resonance (NMR) and Nuclear Quadrupole Resonance (NQR) allow the investigation of electronic properties at the atomic level. We will report on such studies of typical members of the the Y-Ba-Cu-O family such as YBa2Cu30(6 + x) (1-2-3-(6 + x)), YBa2Cu4O8 (1-2-4) and Y2Ba4Cu7015 (2-4-7) with many examples of recent work performed in our laboratory. In particular, we will deal with Knight shift and relaxation studies of copper and oxygen. We will discuss important issues of current studies such as: (1) Existence of a common electronic spin-susceptibility in the planes (and perhaps in the chains) of 1-2-4; (2) Strong evidence for the existence of a pseudo spin-gap of the antiferromagnetic fluctuations in 1-2-4 and 2-4-7; (3) Evidence for d-wave pairing in 1-2-4; (4) Strong coupling of inequivalent Cu-O planes in 2-4-7 and possible origin for the high Tc value of this compound; and (5) The possibility to describe NMR data in the framework of a charge-excitation picture.

Brinkmann, D.

1995-01-01

117

Quadrupole and hexadecapole ordering in DyB2C2: Direct observation with resonant x-ray diffraction  

NASA Astrophysics Data System (ADS)

Direct evidence of the spatial ordering of Dy 4f quadrupole and hexadecapole moments in DyB2C2 is demonstrated by resonant x-ray diffraction enhanced by an electric quadrupole event (E2 resonance) at the Dy LIII absorption edge. The diffraction data show that the structural phase transition at TQ=24.7 K is accompanied by a reduction in the symmetry of the Dy site to 2/m, from 4/m, and the spatial ordering of the time-even Dy multipoles with Ag character. Below TQ the crystal structure is described by the space group P42/mnm and Dy ions occupy sites (4c). The distortion at TQ involves the lattice occupied by B and C ions, and it amounts to a buckling of B-C planes that are normal to the two-fold rotation axis of 2/m. An immediately plausible model of low-energy Dy states correlates data on the specific heat, our x-ray diffraction signals, and magnetic ordering below 15.3 K which has been observed in magnetic neutron diffraction.

Tanaka, Yoshikazu; Inami, Toshiya; Lovesey, Stephen W.; Knight, Kevin S.; Yakhou, Flora; Mannix, Danny; Kokubun, Jun; Kanazawa, Masayuki; Ishida, Kohtaro; Nanao, Susumu; Nakamura, Tetsuya; Yamauchi, Hiroki; Onodera, Hideya; Ohoyama, Kenji; Yamaguchi, Yasuo

2004-01-01

118

Dipole and quadrupole surface plasmon resonance contributions in formation of near-field images of a gold nanosphere  

NASA Astrophysics Data System (ADS)

Multipolar plasmon optical excitations at spherical gold nanoparticles and their manifestations in the particle images formatted in the particle surface proximity are studied. The multipolar plasmon size characteristic: plasmon resonance frequencies and plasmon damping rates were obtained within rigorous size dependent modelling. The realistic, frequency dependent dielectric function of a metal was used. The distribution of light intensity and of electric field radial component at the flat square scanning plane scattered by a gold sphere of radius 95 nm was acquired. The images resulted from the spatial distribution of the full mean Poynting vector including near-field radial components of the scattered electromagnetic field. Monochromatic images at frequencies close to and equal to the plasmon dipole and quadrupole resonance frequencies are discussed. The changes in images and radial components of the scattered electromagnetic field distribution at the scanning plane moved away from the particle surface from near-field to far-field region are discussed.

Shopa, M.; Kolwas, K.; Derkachova, A.; Derkachov, G.

2010-12-01

119

A simple microscopic approach to the nuclear giant monopole and quadrupole resonances  

Microsoft Academic Search

The monopole and quadrupole excitation modes of spin-saturated nuclei are studied by means of sum rules, using a simple density-dependent finite-range interaction with particular emphasis on the effects of the finite range of the interaction on the excitation energies. Within the framework of the density matrix expansion, it is shown that the excitation energies can be related to the various

B. Behera; T. R. Routray

1988-01-01

120

All 36 exactly solvable solutions of eigenvalues for nuclear electric quadrupole interaction Hamiltonian and equivalent rigid asymmetric rotor with expanded characteristic equation listing  

NASA Astrophysics Data System (ADS)

This paper derives all 36 analytical solutions of the energy eigenvalues for nuclear electric quadrupole interaction Hamiltonian and equivalent rigid asymmetric rotor for polynomial degrees 1 through 4 using classical algebraic theory. By the use of double-parameterization the full general solution sets are illustrated in a compact, symmetric, structural, and usable form that is valid for asymmetry parameter ? in ({- ? , + ?}). These results are useful for code developers in the area of Perturbed Angular Correlation (PAC), Nuclear Quadrupole Resonance (NQR) and rotational spectroscopy who want to offer exact solutions whenever possible, rather that resorting to numerical solutions. In addition, by using standard linear algebra methods, the characteristic equations of all integer and half-integer spins I from 0 to 15, inclusive are represented in a compact and naturally parameterized form that illustrates structure and symmetries. This extends Nielson's [1] listing of characteristic equations for integer spins out to I = 15, inclusive.

Menke, Lorenz Harry

2012-05-01

121

Structure and phase transition in bis(pyrrolidinium) hexachlorometallates, (C 4H 8NH 2) 2MCl 6 (M=Sn, Te and Pt), studied by X-ray diffraction, 35Cl NQR and DSC  

NASA Astrophysics Data System (ADS)

Single crystal X-ray diffraction, 35Cl nuclear quadrupole resonance (NQR) and differential scanning calorimetry (DSC) measurements were taken for bis(pyrrolidinium) hexachlorometallates, (C 4H 8NH 2) 2MCl 6 (M=Sn, Te and Pt). A solid-solid phase transition was observed at 150(1), 159(1) and 134(1) K for stannate, tellurate and platinate, respectively. 35Cl NQR signals were observed in stannate and platinate, both of which showed a two-line spectrum in the high-temperature phase and a three-line spectrum in the low-temperature phase. The high-temperature phases of the three complexes were found to be isostructural with each other belonging to the space group C2/ m (#12). The C 4H 8NH 2+ and MCl 62- ions are connected by N-H⋯Cl hydrogen bonds forming parallel sheets in the crystals. Disorder of the cation ring appears in these high-temperature phases. Semi-empirical MO calculations were performed to estimate the stable structure of the pyrrolidinium ion.

Ishida, H.; Furukawa, Y.; Sato, S.; Kashino, S.

2000-06-01

122

Spectral hole burning and optically detected nuclear quadrupole resonance in flux-grown stoichiometric europium vanadate crystals  

SciTech Connect

Earlier work [Cone {ital et al.}, J. Phys. C {bold 17}, 3101 (1984); Cone {ital et al.}, J. Phys.: Condens. Matter {bold 5}, 573 (1993)] on EuVO{sub 4} has described the fluorescence excitation spectra associated with the large number of defect sites ({gt}50) previously discovered in this material. To establish which if any of the defect sites were intrinsic to the EuVO{sub 4} crystal structure rather than being dependent on particular growth procedures, EuVO{sub 4} crystals were prepared from fluxes with different compositions. The present work extends this study, using the techniques of spectral hole burning and optical detection of nuclear quadrupole resonance to examine at much higher precision the degree to which the defect spectra associated with the various crystal growths are identical, and to attempt a preliminary correlation of such spectra with the methods of crystal growth. We discuss the relative importance of the lattice and electronic contributions to the ground-state quadrupole interactions and conclude that the electronic contribution is almost always larger than the lattice contribution. The data also allow conclusions to be drawn regarding the relative importance of {ital pseudoquadrupolar} effects in the spectra and they are found to be small. This work forms a basis for detailed study of particular defect sites to be discussed in further papers. {copyright} {ital 1997} {ital The American Physical Society}

Hansen, P.C.; Leask, M.J.; Wanklyn, B.M. [Clarendon Laboratory, Parks Road, Oxford OX1 3PU (United Kingdom)] [Clarendon Laboratory, Parks Road, Oxford OX1 3PU (United Kingdom); Sun, Y.; Cone, R.L. [Physics Department, Montana State University, Bozeman, Montana 59717 (United States)] [Physics Department, Montana State University, Bozeman, Montana 59717 (United States); Abraham, M.M. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 23223 (United States)] [Oak Ridge National Laboratory, Oak Ridge, Tennessee 23223 (United States)

1997-10-01

123

Magnetic field-cycling NMR and 14N, 17O quadrupole resonance in the explosive pentaerythritol tetranitrate (PETN)  

NASA Astrophysics Data System (ADS)

The explosive pentaerythritol tetranitrate (PETN) C(CH 2-O-NO 2) 4 has been studied by 1H NMR and 14N NQR. The 14N NQR frequency and spin-lattice relaxation time T1Q for the ? + line have been measured at temperatures from 255 to 325 K. The 1H NMR spin-lattice relaxation time T1 has been measured at frequencies from 1.8 kHz to 40 MHz and at temperatures from 250 to 390 K. The observed variations are interpreted as due to hindered rotation of the NO 2 group about the bond to the oxygen atom of the CH 2-O group, which produces a transient change in the dipolar coupling of the CH 2 protons, generating a step in the 1H T1 at frequencies between 2 and 100 kHz. The same mechanism could also explain the two minima observed in the temperature variation of the 14N NQR T1Q near 284 and 316 K, due in this case to the transient change in the 14N 1H dipolar interaction, the first attributed to hindered rotation of the NO 2 group and the second to an increase in torsional amplitude of the NO 2 group due to molecular distortion of the flexible CH 2-O-NO 2 chain which produces a 15% increase in the oscillational amplitude of the CH 2 group. The correlation times governing the 1H T1 values are approximately 25 times longer than those governing the 14N NQR T1Q, explained by the slow spin-lattice cross-coupling between the two spin systems. At higher frequencies, the 1H T1 dispersion results show well-resolved dips between 200 and 904 kHz assigned to level crossing with 14N and weaker features between 3 and 5 MHz tentatively assigned to level crossing with 17O.

Smith, John A. S.; Rayner, Timothy J.; Rowe, Michael D.; Barras, Jamie; Peirson, Neil F.; Stevens, Andrew D.; Althoefer, Kaspar

2010-05-01

124

Magnetic field-cycling NMR and (14)N, (17)O quadrupole resonance in the explosive pentaerythritol tetranitrate (PETN).  

PubMed

The explosive pentaerythritol tetranitrate (PETN) C(CH(2)-O-NO(2))(4) has been studied by (1)H NMR and (14)N NQR. The (14)N NQR frequency and spin-lattice relaxation time T(1Q) for the nu(+) line have been measured at temperatures from 255 to 325K. The (1)H NMR spin-lattice relaxation time T(1) has been measured at frequencies from 1.8kHz to 40MHz and at temperatures from 250 to 390K. The observed variations are interpreted as due to hindered rotation of the NO(2) group about the bond to the oxygen atom of the CH(2)-O group, which produces a transient change in the dipolar coupling of the CH(2) protons, generating a step in the (1)H T(1) at frequencies between 2 and 100kHz. The same mechanism could also explain the two minima observed in the temperature variation of the (14)N NQR T(1Q) near 284 and 316K, due in this case to the transient change in the (14)N...(1)H dipolar interaction, the first attributed to hindered rotation of the NO(2) group and the second to an increase in torsional amplitude of the NO(2) group due to molecular distortion of the flexible CH(2)-O-NO(2) chain which produces a 15% increase in the oscillational amplitude of the CH(2) group. The correlation times governing the (1)H T(1) values are approximately 25 times longer than those governing the (14)N NQR T(1Q), explained by the slow spin-lattice cross-coupling between the two spin systems. At higher frequencies, the (1)H T(1) dispersion results show well-resolved dips between 200 and 904kHz assigned to level crossing with (14)N and weaker features between 3 and 5MHz tentatively assigned to level crossing with (17)O. PMID:20236842

Smith, John A S; Rayner, Timothy J; Rowe, Michael D; Barras, Jamie; Peirson, Neil F; Stevens, Andrew D; Althoefer, Kaspar

2010-05-01

125

Characterization of solid phases and study of transformation kinetics in m-chlorofluorobenzene by 35Cl nuclear quadrupole resonance.  

PubMed

Polymorphism is of widespread occurrence in the world of molecular crystals. In this work we present experimental results showing the existence of four solid phases in m-chlorofluorobenzene. A glass structure is achieved by quenching the liquid phase at 77 K. This glassy state crystallizes in a disordered phase at T~143 K, which in turn transforms to the high-temperature stable phase (phase I) at T~153 K. Depending on the thermal history of the sample, a different ordered phase (phase III) can be obtained. The disorder is attributed to a molecular orientational disorder. There is no evidence of molecular reorientation in any phase. A study of the disorder-order phase transformation kinetics, using nuclear quadrupole resonance, is presented. The results are analyzed following Cahn's theory. Nucleation seems to take place at grain boundaries. Growth rates for different temperatures have been determined. PMID:22209621

Prez, Silvina; Wolfenson, Alberto

2012-02-01

126

Potassium-39 nuclear magnetic resonance of potassium-ionophore complexes: Chemical shifts, relaxation times, and quadrupole coupling constants  

NASA Astrophysics Data System (ADS)

The complexation of K + by several ionophores was studied by 39K nuclear magnetic resonance. With the use of a high magnetic field (8.5 tesla) and a probe with sideways solenoid transmitter/receiver coil, very good signal-to-noise ratios could be obtained in a reasonable experiment time for concentrations as low as 20 m M and linewidths of the order of 250 Hz. Chemical shifts and spin-lattice relaxation times for 39K in the ionophore complexes are reported. The 39K chemical shifts show a large variation in different ligand environments. 13C spin-lattice relaxation times were measured for the potassium-ionophore complexes in order to derive correlation times. 39K quadrupole coupling constants in the different complexes could thus also be calculated. Despite the low sensitivity of 39K for the NMR experiment, the results indicate that 39K NMR studies of potassium-ligand interactions are feasible at millimolar concentrations.

Neurohr, Klaus J.; Drakenberg, Torbjorn; Forsn, Sture; Lilja, Hans

127

Stereoelectronic structure and 35Cl NQR parameters of 4-(trichlorgermyl)butan-2-one using ab initio calculations  

NASA Astrophysics Data System (ADS)

The results of ab initio calculations at the RHF/6-31G(d) and MP2/6-31G(d) levels of two stable structures of the 4-(trichlorgermyl)butan-2-one molecule with total optimization of their geometry have been represented. The structure with pentacoordinated Ge atom is energetically more advantageous as compared with that with tetracoordinated one. Using these results, the 35Cl nuclear quadrupole resonance (NQR) frequencies and asymmetry parameters of the electric field gradient (EFG) at the 35Cl nuclei in molecule with pentacoordinated Ge atom have been assessed, the frequencies satisfactorily agreeing with experimental data. Calculations at the RHF/6-31G(d) level have been performed also at various Ge⋯O distances. It has been demonstrated that convergence of the Ge and O coordination centers leads to the increase of positive charge at the Ge coordination center and of negative charge at the O coordination center, at that, electron density from the Ge atom shifts mainly to the axial Cl atom and from the C atom of carbonyl group - to its O atom. The electron density transfer from the O to Ge atom does not occur.

Feshin, V. P.; Feshina, E. V.

2012-03-01

128

Magnetic correlations in La(2-x)Sr(x)CuO4 from NQR relaxation and specific heat  

NASA Astrophysics Data System (ADS)

La-139 and Cu-63 Nuclear Quadrupole Resonance (NQR) relaxation measurements in La(2-x)Sr(x)CuO4 for O = to or less than 0.3 and in the temperature range 1.6 + 450 K are analyzed in terms of Cu(++) magnetic correlations and dynamics. It is described how the magnetic correlations that would result from Cu-Cu exchange are reduced by mobile charge defects related to x-doping. A comprehensive picture is given which explains satisfactorily the x and T dependence of the correlation time, of the correlation length and of the Neel temperature T(sub n)(x) as well as being consistent with known electrical resistivity and magnetic susceptibility measurements. It is discussed how, in the superconducting samples, the mobile defects also cause the decrease, for T yields T(sub c)(+) of the hyperfine Cu electron-nucleus effective interaction, leading to the coexistence of quasi-localized, reduced magnetic moments from 3d Cu electrons and mobile oxygen p-hole carriers. The temperature dependence of the effective hyperfine field around the superconducting transition yields an activation energy which could be related to the pairing energy. New specific heat measurements are also presented and discussed in terms of the above picture.

Borsa, F.; Rigamonti, A.

1990-04-01

129

Determination of the magnitude and sign of the 185,187Re nuclear electric quadrupole coupling constants using nuclear acoustic resonance  

Microsoft Academic Search

Acoustic nuclear electric quadrupole resonance spectra and the magnitude and sign of the coupling constants for 185Re and 187Re in rhenium-metal single crystals have been measured using nuclear acoustic resonance (NAR) in a small magnetic field. These measurements were carried out using a NAR reflection bridge spectrometer in the 37-41 MHz frequency range and at 4.2 and 77.8 K. In

R. K. Sundfors

1990-01-01

130

Determination of the magnitude and sign of the sup 185,187 Re nuclear electric quadrupole coupling constants using nuclear acoustic resonance  

Microsoft Academic Search

Acoustic nuclear electric quadrupole resonance spectra and the magnitude and sign of the coupling constants for ¹⁸⁵Re and ¹⁸⁷Re in rhenium-metal single crystals have been measured using nuclear acoustic resonance (NAR) in a small magnetic field. These measurements were carried out using a NAR reflection bridge spectrometer in the 37--41 MHz frequency range and at 4.2 and 77.8 K. In

Sundfors

1990-01-01

131

ISOVECTOR GIANT DIPOLE AND QUADRUPOLE RESONANCES AND DIRECT+SEMIDIRECT PHOTONUCLEAR REACTIONS  

Microsoft Academic Search

Results of recent theoretical studies of the direct+semidirect (DSD) photonuclear re- actions in the energy region of the isovector giant resonances (GRs) with an emission of single nucleon (photonucleon reactions) along with the total characteristics of the giant resonances themselves such as total photoabsorption cross sections are presented. The studies were carried out within the semi-microscopic approach based on the

M. L. Gorelik; I. V. Safonov; B. A. Tulupov; M. H. Urin

132

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

NASA Astrophysics Data System (ADS)

The 35Cl nuclear quadrupole resonance frequencies and spin-lattice relaxation times for (NH4)2RuCl6, (ND4)2RuCl6, (NH4)2SnCl6, and (ND4)2SnCl6 were measured in the temperature range 4.2-300 K. In these four compounds, it was confirmed that no phase transition occurs in the observed temperature range. At 4.2 K, discrepancies of the NQR frequency between non-deuterated and deuterated compounds, which are attributed to the difference in the spatial distributions of hydrogen (deuterium) atoms in the ground states of the rotational motion of ammonium ion, reached to 24 kHz and 23 kHz for the ruthenate compounds and the stannate compounds, respectively. The separation between the ground and the first excited states of the rotational motion of the ammonium ion was estimated to be 466 J mol-1 and 840 J mol-1 for (ND4)2RuCl6 and (NH4)2RuCl6, respectively, by least-square fitting calculations of temperature dependence of the NQR frequency. For (ND4)2SnCl6 and (NH4)2SnCl6, these quantities were estimated to be 501 J mol-1 and 1544 J mol-1, respectively. It was clarified that the T1 minimum, which has been observed for the stannate compounds at around 60 K as a feature of the temperature dependence, was dependent on a method of sample preparation. It is concluded that the minimum is not an essential character of the ammonium hexachlorostannate(IV) since the crystals prepared in strong acid condition to prevent a partial substitution of chlorine atoms by hydroxyl groups, did not show such T1 minimum.

Kume, Yoshio; Amino, Daiki; Asaji, Tetsuo

2013-07-01

133

New ? level mixing and nuclear magnetic resonance method for measuring magnetic dipole and electric quadrupole moments of short-lived nuclei  

NASA Astrophysics Data System (ADS)

The level-mixing resonance technique applied to ?-decaying nuclei (?-LMR) is a well-established tool for measuring the ground state quadrupole moments of nuclei away from stability. These experiments yield the quadrupole to magnetic moment ratio, provided the electric field gradient (EFG) of the implanted nuclei in the crystal is known. By combining ?-LMR with ? nuclear magnetic resonance (?-NMR), both the quadrupole moment Q and the magnetic moment ? can be simultaneously extracted in a single experiment. A major advantage of this technique is that the initial nuclei need only to be aligned, and not necessarily polarized. Alignment is generally easier to produce than polarization, and occurs at the highest yield point in the nuclear reaction mechanism. This is an especially important consideration in the study of dipole and quadrupole moments of nuclei in the region of the drip lines. We report here the successful application of this combined technique to the known case of 12B(Mg). The main features of the LMR-NMR technique are described.

Coulier, N.; Neyens, G.; Teughels, S.; Balabanski, D. L.; Coussement, R.; Georgiev, G.; Ternier, S.; Vyvey, K.; Rogers, W. F.

1999-04-01

134

Experimental evidence for ferromagnetic spin-pairing superconductivity emerging in UGe2 : A Ge73 -nuclear-quadrupole-resonance study under pressure  

Microsoft Academic Search

We report that a different type of superconducting order parameter has been realized in the ferromagnetic states in UGe2 via Ge73 -nuclear-quadrupole-resonance experiments performed under pressure (P) . Measurements of the nuclear spin-lattice relaxation rate (1\\/T1) have revealed an unconventional nature of superconductivity such that the up-spin band is gapped with line nodes, but the down-spin band remains gapless at

A. Harada; S. Kawasaki; H. Mukuda; Y. Kitaoka; Y. Haga; E. Yamamoto; Y. Onuki; K. M. Itoh; E. E. Haller; H. Harima

2007-01-01

135

Reply to ``Comment on `Localized behavior near the Zn impurity in Y Ba2 Cu4 O8 as measured by nuclear quadrupole resonance' ''  

NASA Astrophysics Data System (ADS)

Julien have commented on two of our publications, claiming that we have made erroneous interpretations of the nuclear magnetic resonance (NMR) and nuclear quadrupole resonance data. Specifically, they believe that their model of an extended staggered moment about a Zn impurity is the only interpretation of the data [Julien , Phys. Rev Lett. 84, 3422 (2000)]. Not only does their claim ignore models presented by other authors, we show that the model of Julien [Phys. Rev Lett. 84, 3422 (2000)] does not consistently reproduce all of the NMR data.

Williams, G. V. M.; Krmer, S.; Tallon, J. L.; Dupree, R.; Loram, J. W.

2005-05-01

136

"Colored" noise waveforms and quadrupole excitation for the dynamic range expansion of Fourier transform ion cyclotron resonance mass spectrometry.  

PubMed

Fourier transform ion cyclotron resonance (FTICR) mass spectrometry offers unparalleled analytical performance in most regards but has a dynamic range of typically no better than 10(2)-10(3). This limitation reportedly arises from two opposing constraints, involving the maximum number of ions that can be effectively trapped (10(6)-10(7)) and the minimum number of ions required to produce a detectable signal (10(2)-10(3)). A potential solution to this dynamic range limitation is presented, based on the application of selected-ion accumulation using quadrupole excitation. We show that lower concentration species can be effectively accumulated in the FTICR trapped ion cell, while the more abundant species are continually removed by the application of quadrupolar excitation in the form of band-limited or "colored" noise waveforms. The result is that "room" is made in the cell for lower abundance species, even during extended accumulation periods. This approach was demonstrated with mixtures of the bovine proteins, insulin, ubiquitin, and cytochrome c. For normal accumulation, the dynamic range was approximately 100. The application of selected-ion accumulation in the form of colored noise allowed the extension by 2 orders of magnitude and the detection of species of 1 x 10(-8) M concentration from a solution also containing another component at 9 x 10(-5) M. With this method, a putative new low abundance variant of bovine insulin was observed, and selected-ion accumulation and subsequent collisionally activated dissociation were used for its identification. Dipolar magnetron excitation was also explored to enhance selected-ion accumulation and was found to reduce the amount of buffer gas required for complete removal of the undesired species by a factor of 5. Further possible improvements are discussed, as are the complications due to the required balance between magnetron and cyclotron damping rates. PMID:8712362

Bruce, J E; Anderson, G A; Smith, R D

1996-02-01

137

Electron transfer dissociation in the hexapole collision cell of a hybrid quadrupole-hexapole Fourier transform ion cyclotron resonance mass spectrometer.  

PubMed

Electron transfer dissociation (ETD) of proteins is demonstrated in a hybrid quadrupole-hexapole Fourier transform ion cyclotron resonance mass spectrometer (Qh-FTICRMS). Analyte ions are selected in the mass analyzing quadrupole, accumulated in the hexapole linear ion trap, reacted with fluoranthene reagent anions, and then analyzed via an FTICR mass analyzer. The hexapole trap allows for a broad fragment ion mass range and a high ion storage capacity. Using a 3 T FTICRMS, resolutions of 60 000 were achieved with mass accuracies averaging below 1.4 ppm. The high resolution, high mass accuracy ETD spectra provided by FTICR obviates the need for proton transfer reaction (PTR) charge state reduction of ETD product ions when analyzing proteins or large peptides. This is demonstrated with the ETD of ubiquitin and apomyoglobin yielding sequence coverages of 37 and 20%, respectively. We believe this represents the first reported successful combination of ETD and a FTICRMS. PMID:18181247

Kaplan, Desmond A; Hartmer, Ralf; Speir, J Paul; Stoermer, Carsten; Gumerov, Dmitry; Easterling, Michael L; Brekenfeld, Andreas; Kim, Taeman; Laukien, Frank; Park, Melvin A

2008-01-01

138

Detection of {sup 14}N and {sup 35}Cl in cocaine base and hydrochloride using NQR, NMR, and SQUID techniques  

SciTech Connect

Results from {sup 14}N pure NQR of cocaine in the free base form (cocaine base) yield a nuclear quadrupole coupling constant (NQCC) e{sup 2}Qq/h of 5.0229 ({+-}0.0001) MHz and an asymmetry parameter {eta} of 0.0395 ({+-}0.0001) at 295 K, with corresponding values of 5.0460 ({+-}0.0013) MHz and 0.0353 ({+-}0.0008) at 77 K. Both pure NQR (at 295-77 K) and a superconducting quantum interference device (SQUID) detector (at 4.2 K) were used to measure the very low (<1 MHz) {sup 14}N transition frequencies in cocaine hydrochloride; at 295 K the NQCC is 1.1780 ({+-}0.0014) MHz and the asymmetry parameter is 0.2632 ({+-}0.0034). Stepping the carrier frequency enables one to obtain a powder pattern without the severe intensity distortions that otherwise arise from finite pulse power. A powder pattern simulation using an NQCC value of 5.027 MHz and an asymmetry parameter {eta} of 0.2 agrees reasonably well with the experimental stepped-frequency spectrum. The use of pure NQR for providing nondestructive, quantitative, and highly specific detection of crystalline compounds is discussed, as are experimental strategies. 31 refs., 8 figs., 1 tab.

Yesinowski, J.P.; Buess, M.L.; Garroway, A.N. [Naval Research Lab., Washington, DC (United States); Ziegeweid, M.; Pines, A. [Univ. of California, Berkeley, CA (United States)]|[Lawrence Berkeley Lab., CA (United States)

1995-07-01

139

Crystallization and preliminary analysis of the NqrA and NqrC subunits of the Na(+)-translocating NADH:ubiquinone oxidoreductase from Vibrio cholerae.  

PubMed

The Na(+)-translocating NADH:ubiquinone oxidoreductase (Na(+)-NQR) from Vibrio cholerae is a membrane protein complex consisting of six different subunits NqrA-NqrF. The major domains of the NqrA and NqrC subunits were heterologously expressed in Escherichia coli and crystallized. The structure of NqrA1-377 was solved in space groups C2221 and P21 by SAD phasing and molecular replacement at 1.9 and 2.1? resolution, respectively. NqrC devoid of the transmembrane helix was co-expressed with ApbE to insert the flavin mononucleotide group covalently attached to Thr225. The structure was determined by molecular replacement using apo-NqrC of Parabacteroides distasonis as search model at 1.8? resolution. PMID:25005105

Vohl, Georg; Nedielkov, Ruslan; Claussen, Bjrn; Casutt, Marco S; Vorburger, Thomas; Diederichs, Kay; Mller, Heiko M; Steuber, Julia; Fritz, Gnter

2014-07-01

140

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

141

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

2011-02-01

142

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

NASA Astrophysics Data System (ADS)

We present a theoretical study of the nuclear quadrupole interaction, ?Q, of 75As 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-As2S3, a-As2Se3 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.

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

2011-02-01

143

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

144

Experimental evidence for ferromagnetic spin-pairing superconductivity emerging in UGe2 : A Ge73 -nuclear-quadrupole-resonance study under pressure  

NASA Astrophysics Data System (ADS)

We report that a different type of superconducting order parameter has been realized in the ferromagnetic states in UGe2 via Ge73 -nuclear-quadrupole-resonance experiments performed under pressure (P) . Measurements of the nuclear spin-lattice relaxation rate (1/T1) have revealed an unconventional nature of superconductivity such that the up-spin band is gapped with line nodes, but the down-spin band remains gapless at the Fermi level. This result is consistent with that of a ferromagnetic spin-pairing model in which Cooper pairs are formed among ferromagnetically polarized electrons. The present experiment has shed light on the possible origin of ferromagnetic superconductivity, which is mediated by ferromagnetic spin-density fluctuations relevant to the first-order transition inside the ferromagnetic states.

Harada, A.; Kawasaki, S.; Mukuda, H.; Kitaoka, Y.; Haga, Y.; Yamamoto, E.; ?nuki, Y.; Itoh, K. M.; Haller, E. E.; Harima, H.

2007-04-01

145

Pressure-induced unconventional superconductivity in the heavy-fermion antiferromagnet CeIn3 : An In115 -NQR study under pressure  

NASA Astrophysics Data System (ADS)

We report on pressure-induced unconventional superconductivity (SC) in the heavy-fermion (HF) antiferromagnet CeIn3 by means of nuclear-quadrupole-resonance (NQR) studies conducted under a high pressure. The temperature (T) and pressure (P) dependences of the In-NQR spectra have revealed a first-order quantum-phase transition (QPT) from antiferromagnetism (AFM) to paramagnetism (PM) at a critical pressure Pc=2.46GPa at which AFM disappears with a minimum value of TN(Pc)=1.2K . High-energy x-ray scattering measurements under P show a progressive decrease in the lattice density without any change in the crystal structure, whereas an increase in the NQR frequency (?Q) indicates an increase in the hybridization between 4f electrons and conduction electrons, which stabilizes the HF-PM state. This competition between the AFM phase where TN is reduced and the formation of the HF-PM phase triggers the first-order QPT at Pc=2.46GPa . Despite the lack of an AFM quantum critical point in the P-T phase diagram, we highlight the fact that unconventional SC occurs in both phases of AFM and PM. The measurements of the nuclear spin-lattice relaxation rate 1/T1 in the AFM phase have provided evidence for the uniformly coexisting AFM+SC phase. Remarkably, the significant increase in 1/T1 upon cooling in the AFM phase has revealed the development of low-lying magnetic excitations down to Tc in the AFM phase; it is indeed relevant to the onset of the uniformly coexisting AFM+SC phase. In the HF-PM phase where AFM fluctuations are not developed, 1/T1 decreases without the coherence peak just below Tc , followed by a power-law-like T dependence that indicates an unconventional SC with a line-node gap. Remarkably, Tc has a peak around Pc in the HF-PM phase as well as in the AFM phase. In other words, an SC dome exists with a maximum value of Tc=230mK around Pc , indicating that the origin of the pressure-induced HF SC in CeIn3 is not relevant to AFM spin fluctuations but to the emergence of the first-order QPT in CeIn3 . These phenomena observed in CeIn3 should be understood in terms of the first-order QPT because these new phases of matter are induced by applying P . When the AFM critical temperature is suppressed at the termination point of the first-order QPT, Pc=2.46GPa , the diverging AFM spin-density fluctuations emerge at the critical point from AFM to PM. The results with CeIn3 leading to a new type of quantum criticality deserve further theoretical investigations.

Kawasaki, S.; Yashima, M.; Kitaoka, Y.; Takeda, K.; Shimizu, K.; Oishi, Y.; Takata, M.; Kobayashi, T. C.; Harima, H.; Araki, S.; Shishido, H.; Settai, R.; ?nuki, Y.

2008-02-01

146

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

PubMed

Technological advancements including an open-cylindrical Penning trap with capacitively coupled ICR cell, selective ion accumulation with a resolving quadrupole, and a voltage gradient used during ion extraction from an octopole ion trap, have individually improved dynamic range and sensitivity in Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS). Documented here is a new instrument utilizing these technologies toward the robust detection and fragmentation of biomolecules >10 kDa. Up to 55-fold enhancement in ion population by selective ion accumulation combined with 10- to 20- fold signal-to-noise improvement by application of a DC voltage gradient to an accumulation octopole during the ion transfer event offers improved signal-to-noise (or speed) of MS/MS experiments, for proteins from Methanococcus jannaschii and Saccharomyces cerevisiae whole cell lysates. After external quadrupole filtering with a 40 m/z window, three proteins were fragmented (and identified) in parallel from the database of Methanococcus jannaschii. Electron capture dissociation (ECD) of an intact yeast protein provides extensive sequence information resulting in a high degree of localization for an N-terminal acetylation. Hybrid fragmentation, infrared multiphoton dissociation (IRMPD) followed by low energy electrons (ECD), with the electron source located laterally off the z-axis and external to the magnet bore, presents a strategy for identification of proteins by means of the sequence tag approach. Automated implementation of diverse MS(n) approaches in a Q-FTMS instrument promises to help realize "top-down" proteomics in the future. PMID:15234368

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

2004-07-01

147

An automated matrix-assisted laser desorption/ionization quadrupole Fourier transform ion cyclotron resonance mass spectrometer for "bottom-up" proteomics.  

PubMed

Here we describe a new quadrupole Fourier transform ion cyclotron resonance hybrid mass spectrometer equipped with an intermediate-pressure MALDI ion source and demonstrate its suitability for "bottom-up" proteomics. The integration of a high-speed MALDI sample stage, a quadrupole analyzer, and a FT-ICR mass spectrometer together with a novel software user interface allows this instrument to perform high-throughput proteomics experiments. A set of linearly encoded stages allows sub-second positioning of any location on a microtiter-sized target with up to 1536 samples with micrometer precision in the source focus of the ion optics. Such precise control enables internal calibration for high mass accuracy MS and MS/MS spectra using separate calibrant and analyte regions on the target plate, avoiding ion suppression effects that would result from the spiking of calibrants into the sample. An elongated open cylindrical analyzer cell with trap plates allows trapping of ions from 1000 to 5000 m/z without notable mass discrimination. The instrument is highly sensitive, detecting less than 50 amol of angiotensin II and neurotensin in a microLC MALDI MS run under standard experimental conditions. The automated tandem MS of a reversed-phase separated bovine serum albumin digest demonstrated a successful identification for 27 peptides covering 45% of the sequence. An automated tandem MS experiment of a reversed-phase separated yeast cytosolic protein digest resulted in 226 identified peptides corresponding to 111 different proteins from 799 MS/MS attempts. The benefits of accurate mass measurements for data validation for such experiments are discussed. PMID:14570192

Brock, Ansgar; Horn, David M; Peters, Eric C; Shaw, Christopher M; Ericson, Christer; Phung, Qui T; Salomon, Arthur R

2003-07-15

148

Dipole and quadrupole surface plasmon resonance contributions in formation of near-field images of a gold nanosphere  

Microsoft Academic Search

Multipolar plasmon optical excitations at spherical gold nanoparticles and their manifestations in the particle images formatted\\u000a in the particle surface proximity are studied. The multipolar plasmon size characteristic: plasmon resonance frequencies and\\u000a plasmon damping rates were obtained within rigorous size dependent modelling. The realistic, frequency dependent dielectric\\u000a function of a metal was used. The distribution of light intensity and of

M. Shopa; K. Kolwas; A. Derkachova; G. Derkachov

2010-01-01

149

Stability and molecular dynamics of chloroxylenol (API of antiseptics and drugs) in solid state studied by 35Cl-NQR spectroscopy and DFT calculations  

NASA Astrophysics Data System (ADS)

Thermal stability of 4-chloro-3,5-dimethyl-phenol (chloroxylenol) in solid state has been studied by 35Cl-NQR spectroscopy. Two NQR resonance lines at the frequencies 34.348 and 34.415 MHz at 77 K have been assigned to chlorine atoms from two crystallographically inequivalent molecules on the basis of the B3LYP/6-311++G ?? results. The temperature dependence of the resonance frequency and full width at half maximum suggest the occurrence of small-angle torsional oscillations of the mean activation energy of 3.83 kJ/mol and rotation of both methyl groups around their symmetry axis C3 with the activation energies 12.49 and 11.27 kJ/mol for CH 3 in molecule A and B, respectively. B3LYP/6-311++G ?? method reproduced very well the activation energies of both motions.

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

2009-02-01

150

NQR spin-echo methods at very low temperatures  

Microsoft Academic Search

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

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

1991-01-01

151

Pulsed Quadrupole Magnet Systems for the Polarized Beam Acceleration at the KEK 12 GeV PS.  

National Technical Information Service (NTIS)

Design and operation of the pulsed quadrupole magnets to correct the intrinsic depolarizing resonances in the KEK PS are described. Rise time of the pulsed quadrupole magnets is set to correct resonances corresponding to each resonance strength. Conventio...

H. Sato D. Arakawa S. Hiramatsu T. Toyama

1987-01-01

152

27Al-NQR\\/NMR Study of Kondo Semiconductor CeFe2Al10  

Microsoft Academic Search

27Al-NQR\\/NMR measurements have been performed on CeFe2Al10 in relevance to the novel phase below T0=27 K of isostructural CeRu2Al10. NQR peaks are assigned to five crystallographically inequivalent Al sites. No splitting of the NQR spectra down to 1.5 K confirms the lack of phase transition in this compound. The gaplike decrease in the spin-lattice relaxation rate 1\\/T1 above about 20

Yukihiro Kawamura; Shingo Edamoto; Tomoaki Takesaka; Takashi Nishioka; Harukazu Kato; Masahiro Matsumura; Yo Tokunaga; Shinsaku Kambe; Hiroshi Yasuoka

2010-01-01

153

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

2012-10-01

154

Nuclear magnetic resonance experiments with dc SQUID amplifiers  

SciTech Connect

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

Heaney, M.B. (California Univ., Berkeley, CA (USA). Dept. of Physics Lawrence Berkeley Lab., CA (USA))

1990-11-01

155

Simultaneous and direct measurement of the neutron-fission branching ratio of uranium-238 in the region of the giant quadrupole resonance  

SciTech Connect

We have measured the coincidence cross-sections {sup 238}U({alpha},{alpha}{prime}nf) and {sup 238}U ({alpha},{alpha}{prime}f), and inclusive cross-sections {sup 238}U({alpha},{alpha}{prime}) using the 120 MeV alpha particle beam at the Lawrence Berkeley Laboratory's 88-Inch Cyclotron. The ({alpha},{alpha}{prime}nf) experiment simultaneously measured the cross-sections for {sup 238}U({alpha},{alpha}{prime}f) and {sup 238}U({alpha},{alpha}{prime}nf) at {theta}{sub {alpha}{prime}}, {approx} 17{degree}, a local maximum for the angular distributions of the isoscalar giant quadrupole and monopole resonances (GQ{sub 0}R and GM{sub 0}R). The branching ration {Gamma}{sub n}/{Gamma}{sub f} obtained from this experiment is therefore not subject to many of the systematic errors which go into the individual cross-sections. The energy of the scattered {alpha}-particle (E{sub {alpha}{prime}}) and the neutron time-of-flight were measured for each event. Fission events were detected using a large solid-angle array, so that the fission neutrons could be removed from the neutron decay spectra. This enabled us to make the first measurement of the neutron decay from an actinide nucleus. Inelastic scattering cross-sections are presented for the range of excitation energy from 0. to 20. MeV. In a separate experiment, the cross-section d{sup 2}{sigma}({alpha},{alpha}{prime}f)/d{Omega}{sub {alpha}},dE{sub {alpha}{prime}} was measured for uranium at seven scattering angles in the range {theta}{sub {alpha}{prime}} = 7-21{degree}. We extracted the transition strength as a function of excitation energy for the GQ{sub 0}R and GM{sub 0}R. In ({alpha},{alpha}{prime}f), we find 25% of the L = 2 energy-weighted sum-rule (from 8 to 12 MeV), and 50% of the L = 0 sum-rule (12 to 16 MeV). The strength agrees well with a recent (e,e{prime}f) experiment.

Countryman, P.J.

1988-01-01

156

Fermilab Tevatron quadrupoles  

SciTech Connect

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

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

1983-03-01

157

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

158

Molecular near-field antenna effect in resonance hyper-Raman scattering: Intermolecular vibronic intensity borrowing of solvent from solute through dipole-dipole and dipole-quadrupole interactions  

NASA Astrophysics Data System (ADS)

We quantitatively interpret the recently discovered intriguing phenomenon related to resonance Hyper-Raman (HR) scattering. In resonance HR spectra of all-trans-?-carotene (?-carotene) in solution, vibrations of proximate solvent molecules are observed concomitantly with the solute ?-carotene HR bands. It has been shown that these solvent bands are subject to marked intensity enhancements by more than 5 orders of magnitude under the presence of ?-carotene. We have called this phenomenon the molecular-near field effect. Resonance HR spectra of ?-carotene in benzene, deuterated benzene, cyclohexane, and deuterated cyclohexane have been measured precisely for a quantitative analysis of this effect. The assignments of the observed peaks are made by referring to the infrared, Raman, and HR spectra of neat solvents. It has been revealed that infrared active and some Raman active vibrations are active in the HR molecular near-field effect. The observed spectra in the form of difference spectra (between benzene/deuterated benzene and cyclohexane/deuterated cyclohexane) are quantitatively analyzed on the basis of the extended vibronic theory of resonance HR scattering. The theory incorporates the coupling of excited electronic states of ?-carotene with the vibrations of a proximate solvent molecule through solute-solvent dipole-dipole and dipole-quadrupole interactions. It is shown that the infrared active modes arise from the dipole-dipole interaction, whereas Raman active modes from the dipole-quadrupole interaction. It is also shown that vibrations that give strongly polarized Raman bands are weak in the HR molecular near-field effect. The observed solvent HR spectra are simulated with the help of quantum chemical calculations for various orientations and distances of a solvent molecule with respect to the solute. The observed spectra are best simulated with random orientations of the solvent molecule at an intermolecular distance of 10 .

Shimada, Rintaro; Hamaguchi, Hiro-o.

2014-05-01

159

Molecular near-field antenna effect in resonance hyper-Raman scattering: Intermolecular vibronic intensity borrowing of solvent from solute through dipole-dipole and dipole-quadrupole interactions.  

PubMed

We quantitatively interpret the recently discovered intriguing phenomenon related to resonance Hyper-Raman (HR) scattering. In resonance HR spectra of all-trans-?-carotene (?-carotene) in solution, vibrations of proximate solvent molecules are observed concomitantly with the solute ?-carotene HR bands. It has been shown that these solvent bands are subject to marked intensity enhancements by more than 5 orders of magnitude under the presence of ?-carotene. We have called this phenomenon the molecular-near field effect. Resonance HR spectra of ?-carotene in benzene, deuterated benzene, cyclohexane, and deuterated cyclohexane have been measured precisely for a quantitative analysis of this effect. The assignments of the observed peaks are made by referring to the infrared, Raman, and HR spectra of neat solvents. It has been revealed that infrared active and some Raman active vibrations are active in the HR molecular near-field effect. The observed spectra in the form of difference spectra (between benzene/deuterated benzene and cyclohexane/deuterated cyclohexane) are quantitatively analyzed on the basis of the extended vibronic theory of resonance HR scattering. The theory incorporates the coupling of excited electronic states of ?-carotene with the vibrations of a proximate solvent molecule through solute-solvent dipole-dipole and dipole-quadrupole interactions. It is shown that the infrared active modes arise from the dipole-dipole interaction, whereas Raman active modes from the dipole-quadrupole interaction. It is also shown that vibrations that give strongly polarized Raman bands are weak in the HR molecular near-field effect. The observed solvent HR spectra are simulated with the help of quantum chemical calculations for various orientations and distances of a solvent molecule with respect to the solute. The observed spectra are best simulated with random orientations of the solvent molecule at an intermolecular distance of 10. PMID:24880300

Shimada, Rintaro; Hamaguchi, Hiro-O

2014-05-28

160

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

161

The direct injection of intense ion beams from a high field electron cyclotron resonance ion source into a radio frequency quadrupole.  

PubMed

The ion current achievable from high intensity ECR sources for highly charged ions is limited by the high space charge. This makes classical extraction systems for the transport and subsequent matching to a radio frequency quadrupole (RFQ) accelerator less efficient. The direct plasma injection (DPI) method developed originally for the laser ion source avoids these problems and uses the combined focusing of the gap between the ion source and the RFQ vanes (or rods) and the focusing of the rf fields from the RFQ penetrating into this gap. For high performance ECR sources that use superconducting solenoids, the stray magnetic field of the source in addition to the DPI scheme provides focusing against the space charge blow-up of the beam. A combined extraction/matching system has been designed for a high performance ECR ion source injecting into an RFQ, allowing a total beam current of 10 mA from the ion source for the production of highly charged (238)U(40+) (1.33 mA) to be injected at an ion source voltage of 60 kV. In this design, the features of IGUN have been used to take into account the rf-focusing of an RFQ channel (without modulation), the electrostatic field between ion source extraction and the RFQ vanes, the magnetic stray field of the ECR superconducting solenoid, and the defocusing space charge of an ion beam. The stray magnetic field is shown to be critical in the case of a matched beam. PMID:24593474

Rodrigues, G; Becker, R; Hamm, R W; Baskaran, R; Kanjilal, D; Roy, A

2014-02-01

162

27Al-NQR Study on Novel Phase Transition in CeOs2Al10  

NASA Astrophysics Data System (ADS)

We have performed 27Al-NQR measurements in CeOs2Al10 which exhibits a novel phase transition at T0=29 K The NQR parameters determined for all the Al sites in ambient pressure were compared with those in CeRu2Al10 with T0=27 K and CeFe2Al10 with no phase transition. The distinct NQR splitting just below T0=32.5 K under pressure 0.66 GPa ensures an enhancement of T0 and a homogeneous transition. Despite the increase of T0, the nuclear spin-lattice relaxation rate 1/Tl is suppressed over whole range of temperature than in ambient pressure. The characteristic features of no critical slowing down at T0 and of the remarkable decrease of 1/T1T starting at T > T0 become prominent under pressure, suggesting an approach to Kondo semiconductor in a valence fluctuation regime.

Matsumura, M.; Inagaki, T.; Kato, H.; Nishioka, T.; Tanida, H.; Sera, M.

2012-12-01

163

NQR1 controls lifespan by regulating the promotion of respiratory metabolism in yeast  

PubMed Central

Summary The activity and expression of plasma membrane NADH coenzyme Q reductase is increased by calorie restriction (CR) in rodents. Although this effect is well established and is necessary for CR's ability to delay aging, the mechanism is unknown. Here we show that the Saccharomyces cerevisiae homolog, NQR1, resides at the plasma membrane and when overexpressed extends both replicative and chronological lifespan. We show that NQR1 extends replicative lifespan in a SIR2-dependent manner by shifting cells towards respiratory metabolism. Chronological lifespan extension, in contrast, occurs via a SIR2-independent decrease in ethanol production. We conclude that NQR1 is a key mediator of lifespan extension by CR through its effects on yeast metabolism and discuss how these findings could suggest a function for this protein in lifespan extension in mammals.

Jimenez-Hidalgo, Maria; Santos-Ocana, Carlos; Padilla, Sergio; Villalba, Jose M.; Lopez-Lluch, Guillermo; Martin-Montalvo, Alejandro; Minor, Robin K.; Sinclair, David A.; de Cabo, Rafael; Navas, Placido

2009-01-01

164

Solid-state (127)I NMR and GIPAW DFT study of metal iodides and their hydrates: structure, symmetry, and higher-order quadrupole-induced effects.  

PubMed

Central-transition (127)I solid-state nuclear magnetic resonance (SSNMR) spectra are presented for several anhydrous group 2 metal iodides (MgI(2), CaI(2), SrI(2), and BaI(2)), hydrates (BaI(2)2H(2)O and SrI(2)6H(2)O), and CdI(2) (4H polytype). Variable offset cumulative spectrum data acquisition coupled with echo pulse sequences and an 'ultrahigh' applied field of 21.1 T were usually suitable to acquire high-quality spectra. Spectral analysis revealed iodine-127 nuclear quadrupole coupling constants (C(Q)((127)I)) ranging in magnitude from 43.5 (CaI(2)) to 214 MHz (one site in SrI(2)). For very large C(Q), analytical second-order perturbation theory could not be used to reliably extract chemical shifts and a treatment which includes quadrupolar effects exactly was required (Bain, A. D. Mol. Phys. 2003, 101, 3163). Differences between second-order and exact modeling allowed us to observe 'higher-order' quadrupole-induced effects for the first time. This finding will have implications for the interpretation of SSNMR spectra of quadrupolar nuclei with large quadrupole moments. In favorable situations (i.e., C(Q)((127)I) < 120 MHz), measurements were also performed at 11.75 T which when combined with the 21.1 T data allowed us to measure iodine chemical shift (CS) tensor spans in the range from 60 (BaI(2)2H(2)O) to 300 ppm (one site in BaI(2)). These measurements represent the first complete characterizations (i.e., electric field gradient and CS tensors as well as their relative orientation) of noncubic iodide sites using (127)I SSNMR. In select cases, the SSNMR data are supported with (127)I NQR measurements. We also summarize a variety of trends in the halogen SSNMR parameters for group 2 metal halides. Gauge-including projector-augmented wave DFT computations are employed to complement the experimental observations, to predict potential structures for the two hydrates, and to highlight the sensitivity of C(Q)((127)I) to minute structural changes, which has potential applications in NMR crystallography. PMID:20860347

Widdifield, Cory M; Bryce, David L

2010-10-14

165

Cu-NQR of CeCu2Si2 under high pressure  

NASA Astrophysics Data System (ADS)

We have measured 63Cu-NQR spectral lines and nuclear spin-lattice relaxation time T1 under pressure up to 5.4 GPa. Daphne oil 7474 is used as the pressure-transmitting medium to obtain good hydrostaticity. NQR frequency 63?q above 4 GPa suddenly decreases from the linear pressure dependence in the low pressure range (P <= 3.5 GPa). The observed sudden downward deviation of 63?q is associated with an increase of Ce valence. Above 4.5 GPa, the linear pressure dependence of 63?q is observed again, most likely related to the sharp crossover to the high valence state.

Fujiwara, K.; Iwata, M.; Okazaki, Y.; Ikeda, Y.; Araki, S.; Kobayashi, T. C.; Murata, K.; Geibel, C.; Steglich, F.

2012-12-01

166

High gradient superconducting quadrupoles  

SciTech Connect

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

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

1987-07-01

167

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

168

Relaxation Anomalies of 69/71Ga NQR in the Paramagnetic State of the Itinerant Antiferromagnet UGa3: Possible Evidence for a Crossover to Localized Spin Fluctuations and Development of Orbital Fluctuations of 5f-electrons at High Temperatures  

NASA Astrophysics Data System (ADS)

The microscopic magnetic properties of the itinerant 5f-electron antiferromagnet UGa3 (TN=67 K) have been investigated in the paramagnetic state by means of Ga NQR studies of the two naturally abundant isotopes 69Ga and 71Ga. A striking and unusual increase of the nuclear longitudinal relaxation rate 1/T1 has been observed above 230 K, which includes a strong component of nuclear quadrupolar relaxation. Both the magnetic and quadrupolar relaxation rates have been found to increase simultaneously above 230 K. Correspondingly, the NQR frequencies also show a clear deviation from lower-T T3/2-dependence above 230 K. These results are discussed in terms of a crossover from lower-T itinerant to higher-T more localized spin fluctuations and associated orbital fluctuations on the part of the U 5f electrons. A mechanism of transferred quadrupole interaction is presented, through which the fluctuations among the U 5f orbitals involve those among the counter-anion Ga 4p orbitals and thereby cause quadrupolar relaxation of the Ga nuclear spins.

Takagi, Shigeru; Muraoka, Hideaki; Matsuda, Tatsuma D.; Haga, Yoshinori; Kambe, Shinsaku; Walstedt, Russell E.; Yamamoto, Etsuji; ?nuki, Yoshichika

2004-02-01

169

Multipulse sequences for explosives detection by NQR under conditions of magnetoacoustic and piezoelectric ringing  

Microsoft Academic Search

A number of methods for cancelling magnetoacoustic and piezoelectric ringing signals in the spectroscopy of the nuclear quadrupole\\u000a resonance are presented. The suggested methods include using the sequence (?0)?-(?-?x-2?-?\\u000a y\\u000a -2?-??x\\u000a -2?-??y\\u000a -?)\\u000a n\\u000a and a multipulse analog of the two-pulse Hahn sequence with the first pulse replaced by a short steady-state sequence. Another\\u000a method presented is the method of

V. T. Mikhaltsevitch; T. N. Rudakov; J. H. Flexman; P. A. Hayes; W. P. Chisholm

2004-01-01

170

Measurement of the spin-lattice relaxation time in the NQR of light nuclei  

SciTech Connect

This work proposed a method for increasing the signal/noise ratio in NQR by preliminary magnetization of the sample in a constant magnetic field B/sub 0/ and it subsequent adiabatic demagnetization. The proposed method for the measurement of spin-lattice relaxation times is verified experimentally with a number of compounds. The results agree well with published data.

Anferov, V.P.; Anferova, S.V.; Grechishkin, V.S.; Sinyavskii, N.Ya.

1988-01-01

171

Nuclear quadrupole resonance studies on weak exchange interactions between paramagnetic ions in M(II)(H2O)6SnCl6 (M(II) = Mn, Co, and Ni)  

NASA Astrophysics Data System (ADS)

The 35Cl NQR spin-lattice relaxation times T1Q in paramagnetic Mn(H2O)6SnCl6 and Co(H2O)6SnCl6 crystals were measured as a function of temperature. Using the T1Q values observed, the correlation times ?f of electron-spin flip-flops and exchange parameters J were estimated. The J value in Mn salt was found to be smaller than those found for Co and Ni salts. It is inferred from the J values that the indirect interaction where some chemical bonds (including OH...Cl hydrogen bonds) intervene is dominant in the exchange interactions between the paramagnetic ions in M(II)(H2O)6SnCl6 (M(II) = Mn, Co and Ni).

Miyoshi, Hiroshi; Ikeda, Ryuichi; Koshio, Akira; Horiuchi, Keizo

2002-02-01

172

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

173

Novel phase diagram of superconductivity and ferromagnetism in UGe2: a 73Ge-NQR study under high pressure  

Microsoft Academic Search

We report on the pressure-induced novel phases of ferromagnetism (FM) and superconductivity (SC) in the itinerant ferromagnet UGe2 through 73Ge-NQR measurements under pressure (P). The P dependence of the NQR spectrum points to a first-order transition from strongly to weakly polarized ferromagnetic phases (SP and WP) around a critical pressure of P_{\\\\mathrm {c}}^*\\\\sim 1.2 GPa. Furthermore, it shows the phase

Y. Kitaoka; H. Kotegawa; A. Harada; S. Kawasaki; Y. Kawasaki; Y. Haga; E. Yamamoto; Y. Onuki; K. M. Itoh; E. E. Haller; H. Harima

2005-01-01

174

Evidence for the microscopic coexistence of superconductivity and ferromagnetism in UGe2:Ge-NMR\\/NQR study  

Microsoft Academic Search

We report on the pressure-induced novel phases of ferromagnetism and superconductivity (SC) in the itinerant ferromagnet UGe2 via the 73Ge-NQR measurements under pressure (P). The NQR spectrum has revealed that the ferromagnetic phases are separated into weakly and strongly polarized phases around a critical value of Pc*1.2GPa, pointing to a first-order transition around Pc*. Here we present further evidence for

A. Harada; H. Kotegawa; Y. Kawasaki; G.-Q. Zheng; Y. Kitaoka; E. Yamamoto; Y. Haga; Y. Onuki; K. Itoh; E. E. Haller

2005-01-01

175

Evidence for Uniform Coexistence of Ferromagnetism and Unconventional Superconductivity in UGe2: A 73Ge-NQR Study under Pressure  

Microsoft Academic Search

We report on the itinerant ferromagnetic superconductor UGe2 through 73Ge-NQR measurements under pressure (P). The P dependence of the NQR spectrum signals a first-order transition from the low-temperature (T) and low-P ferromagnetic phase (FM2) to high-T and high-P one (FM1) around a critical pressure of Px 1.2 GPa. The superconductivity exhibiting a maximum value of Tsc=0.7 K at Px

H. Kotegawa; A. Harada; S. Kawasaki; Y. Kawasaki; Y. Kitaoka; Y. Haga; E. Yamamoto; Y. Onuki; K. M. Itoh; E. E. Haller; H. Harima

2005-01-01

176

Mass spectrometric evidence for collisionally induced removal of H(2) from monoanions of (10)B nido-carborane derivatives investigated by electrospray ionization quadrupole linear ion trap and Fourier transform ion cyclotron resonance mass spectrometry.  

PubMed

Some newly synthesized (10)B nido-carborane derivatives, i.e., 7,8-dicarba-nido-undecaborane monoanions ([7-Me-8-R-C(2)B(9)H(10)](-)K(+), R = H, butyl, hexyl, octyl and decyl), have been fully characterised and examined by electrospray ionization and Fourier transform ion cyclotron resonance mass spectrometry with liquid chromatographic separation (LC/ESI-FTICR-MS). These boron-containing compounds exhibit abundant molecular ions ([M](-)) at m/z 140.22631 [C(3) (10)B(9)H(14)](-), m/z 196.28883 [C(7) (10)B(9)H(22)](-), m/z 224.32032 [C(9) (10)B(9)H(26)](-), m/z 252.35133 [C(11) (10)B(9)H(30)](-) and m/z 280.38354 [C(13) (10)B(9)H(34)](-) at the normal tube lens voltage setting of -90 V, which was an instrumental parameter value selected in the tuning operation. Additional [M-nH(2)](-) (n = 1-4) ions were observed in the mass spectra when higher tube lens voltages were applied, i.e., -140 V. High-resolution FTICR-MS data revealed the accurate masses of fragment ions, bearing either an even or an odd number of electrons. Collision-induced dissociation of the [M-nH(2)](-) ions (n = 0-4) in the quadrupole linear ion trap (LTQ) analyzer confirmed the loss of hydrogen molecules from the molecular ions. It is suggested that the loss of H(2) molecules from the alkyl chain is a consequence of the stabilization effect of the nido-carborane charged polyhedral skeleton. PMID:19504487

Cataldi, Tommaso R I; Ricciardi, Giampaolo; Bianco, Giuliana; Pietrangeli, Daniela; Abate, Salvatore

2009-07-01

177

Identification of 20(S)-protopanaxatriol metabolites in rats by ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry and nuclear magnetic resonance spectroscopy.  

PubMed

20(S)-Protopanaxatriol (PPT), one of the aglycones of ginsenosides, has been shown to exert cardioprotective effects against myocardial ischemic injury. However, studies on PPT metabolism have rarely been reported. This study is the first to investigate the in vivo metabolism of PPT following oral administration by ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC-Q/TOF-MS) and nuclear magnetic resonance (NMR) spectroscopy. The structures of the metabolites were identified based on the characteristics of their MS data, MS(2) data, and chromatographic retention times. A total of 22 metabolites, including 17 phase I and 5 phase II metabolites, were found and tentatively identified by comparing their mass spectrometry profiles with those of PPT. Two new monooxygenation metabolites, (20S,24S)-epoxy-dammarane-3,6,12,25-tetraol and (20S,24R)-epoxy-dammarane-3,6,12,25-tetraol, were chemicallly synthesized and unambiguously characterized according to the NMR spectroscopic data. The metabolic pathways of PPT were proposed accordingly for the first time. Results revealed that oxidation of (1) double bonds at ?((24,25)) to form 24,25-epoxides, followed by rearrangement to yield 20,24-oxide forms; and (2) vinyl-methyl at C-26/27 to form corresponding carboxylic acid were the predominant metabolic pathways. Phase II metabolic pathways were proven for the first time to consist of glucuronidation and cysteine conjugation. This study provides valuable and new information on the metabolism of PPT, which is indispensable for understanding the safety and efficacy of PPT, as well as its corresponding ginsenosides. PMID:24184656

He, Chunyong; Zhou, Dandan; Li, Jia; Han, Han; Ji, Guang; Yang, Li; Wang, Zhengtao

2014-01-01

178

Stabilized radio frequency quadrupole  

DOEpatents

A long-vane stabilized radio frequency resonator for accelerating charged particles and including means defining a radio frequency resonator cavity, a plurality of long vanes mounted in the defining means for dividing the cavity into sections, and means interconnecting opposing ones of the plurality of vanes for stabilizing the resonator.

Lancaster, Henry D. (Orinda, CA); Fugitt, Jock A. (Berkeley, CA); Howard, Donald R. (Danville, CA)

1984-01-01

179

Neutral-Ionic Phase Transition in DMTTF-QCl4 Investigated by 35Cl NQR  

NASA Astrophysics Data System (ADS)

We report a 35Cl NQR investigation into the neutral-ionic (NI) phase transition in DMTTF-QCl4 (4,4'-dimethyltetrathiafulvalene- p-chloranil), the end material of the family containing an NI quantum transition system. Four distinct lines with comparable intensities were observed well below Tc=65 K; this observation is consistent with the antiferroelectric nature of the ionic phase. The temperature dependences of the spectral shift and splitting below Tc are moderate in contrast with the case of TTF-QCl4. Low-energy charge-lattice fluctuations are observed around Tc as a drastic increase of 1/T1, allowing the observation of the quantum fluctuations in a chemically substituted complex. An analysis of the NQR spectra yields detailed temperature variations in the charge transfer and the concomitant lattice distortion around the NI transition.

Iwase, Fumitatsu; Miyagawa, Kazuya; Fujiyama, Shigeki; Kanoda, Kazushi; Horiuchi, Sachio; Tokura, Yoshinori

2007-07-01

180

Ru NQR Probe of Superconducting Property in Impurity-Doped CeRu 2  

Microsoft Academic Search

Superconducting characteristics of CeRu2 have been investigated by systematic measurements of the nuclear-spin lattice relaxation rate, 1\\/T1 of 101Ru on pure and impurity-substituted CeRu2, employing an NQR technique in zero magnetic field. (1\\/T1) for CeRu2 shows a broad coherence plateau just below T c followed by an exponential decrease well below T c. By contrast, a distinct coherence peak of

Hidekazu Mukuda; Kenji Ishida; Yoshio Kitaoka; Kunisuke Asayama

1998-01-01

181

Addition compounds of antimony trichloride and tribromide. Crystal structure and charge transfer from NQR data  

NASA Astrophysics Data System (ADS)

The correlation analysis of the quadrupcle coupling constants(QCC) for the antimony nuclei in the intermolecular compounds of SbCl 3 and SbBr 3 with aromatic hydrocarbons is carried out. The results confirm a supposition about the general similarity of the crystal structures of these complexes. The correlative dependence between the antimony QCC values and also the results of the chlorine and bromine NQR spectra Investigation permit the evaluation of the relative acceptor strength of the antimony trihalide molecules.

Kjuntsel, I. A.; Gordeev, A. D.

182

27Al-NQR/NMR Study of Kondo Semiconductor CeFe2Al10  

NASA Astrophysics Data System (ADS)

27Al-NQR/NMR measurements have been performed on CeFe2Al10 in relevance to the novel phase below T0=27 K of isostructural CeRu2Al10. NQR peaks are assigned to five crystallographically inequivalent Al sites. No splitting of the NQR spectra down to 1.5 K confirms the lack of phase transition in this compound. The gaplike decrease in the spin-lattice relaxation rate 1/T1 above about 20 K, following the Korringa law (T1T = const.) below 20 K, indicates a pseudogap opening near the Fermi level. The gap magnitude of 70 K with a mid-gap state of 42% is estimated based on a rectangular density of states. The gap magnitude is much larger than the gap of 15 K evaluated previously from the electrical resistivity, which suggests CeFe2Al10 to be a Kondo semiconductor with a Kondo temperature much higher than 300 K.

Kawamura, Yukihiro; Edamoto, Shingo; Takesaka, Tomoaki; Nishioka, Takashi; Kato, Harukazu; Matsumura, Masahiro; Tokunaga, Yo; Kambe, Shinsaku; Yasuoka, Hiroshi

2010-10-01

183

Profiling of N-acyl-homoserine lactones by liquid chromatography coupled with electrospray ionization and a hybrid quadrupole linear ion-trap and Fourier-transform ion-cyclotron-resonance mass spectrometry (LC-ESI-LTQ-FTICR-MS).  

PubMed

A method for the comprehensive profiling of the N-acyl-homoserine lactone (AHL) family of bacterial quorum-sensing molecules is presented using liquid chromatography (LC) coupled to a hybrid quadrupole linear ion trap (LTQ) and Fourier-transform ion-cyclotron-resonance mass spectrometer (FTICR). We demonstrate an increase in signal intensity in MS with electrospray ionization (ESI) of the protonated molecules, [M + H](+), by using acetonitrile (ACN) instead of methanol (MeOH) as the organic solvent under the conditions in which the samples were supplied to the probe by direct infusion at constant flow rates. The presence of ACN prevents the formation of methanol adducts such as [M + MeOH + H](+) and [M + MeOH + Na](+), while also lowering the signal intensity of sodiated [M + Na](+) ions. Sensitivity of these signaling molecules in terms of signal-to-noise ratio (S/N) using low-resolution LTQ-MS and high-resolution FTICR-MS were compared under reversed-phase (RP) LC separations with ESI interface. Special emphasis was paid to the choice of the separation column, its elution conditions and detection of the major AHL compounds produced by the Serratia liquefaciens strain ATCC 27592. The most promising results were obtained using a RP C16-amide column eluted with a linear mobile phase gradient ACN/H(2)O containing 0.1% formic acid. The whole set of AHL homologs in bacterial extracts was detected in the extracted-ion chromatographic (XIC) mode, and the calculations of molecular formulae were performed by including the isotopic pattern. This mode of displaying data, with a very narrow mass-to-charge ratio window (i.e. +/- 0.0010 as m/z unit) around each selected ion, has allowed the identification of all the eight known homoserine lactones, viz. C(4)-HSL, 3-oxo-C(6)-HSL, C(6)-HSL, 3-oxo-C(8)-HSL, C(8)-HSL, C(10)-HSL, C(12)-HSL and C(14)-HSL. In addition, at least four uncommon signaling mediators previously unreported, namely, 3-oxo-C(10:1)-HSL, 3-oxo-C(11:2)-HSL, 3-oxo-C(13:2)-HSL and 3-OH-C(16)-HSL, were identified and characterized; their roles in cell-to-cell communication has to be elucidated. PMID:17708516

Cataldi, Tommaso R I; Bianco, Giuliana; Abate, Salvatore

2008-01-01

184

Analysis of S-adenosylmethionine and related sulfur metabolites in bacterial isolates of Pseudomonas aeruginosa (BAA-47) by liquid chromatography/electrospray ionization coupled to a hybrid linear quadrupole ion trap and Fourier transform ion cyclotron resonance mass spectrometry.  

PubMed

A comprehensive and highly selective method for detecting in bacterial supernatants a modified sulfur nucleoside, S-adenosyl-L-methionine (SAM), and its metabolites, i.e., S-adenosylhomocysteine (SAH), adenosine (Ado), 5'-deoxy-5'-methylthioadenosine (MTA), adenine (Ade), S-adenosyl-methioninamine (dcSAM), homocysteine (Hcy) and methionine (Met), was developed. The method is based on reversed-phase liquid chromatography with positive electrospray ionization (ESI+) coupled to a hybrid linear quadrupole ion trap (LTQ) and 7-T Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS). A gradient elution was employed with a binary solvent of 0.05 M ammonium formate at pH 4 and acetonitrile. The assay involves a simultaneous cleanup of cell-free bacterial broths by solid-phase extraction and trace enrichment of metabolites with a 50-fold concentration factor by using immobilized phenylboronic and anion-exchange cartridges. While the quantitative determination of SAM was performed using stable-isotope-labeled SAM-d3 as an internal standard, in the case of Met and Ade, Met-13C and Ade-15N2 were employed as isotope-labeled internal standards, respectively. This method enabled the identification of SAM and its metabolites in cell-free culture of Pseudomonas aeruginosa grown in Davis minimal broth (formulation without sulphur organic compounds), with routine sub-ppm mass accuracies (-0.27 +/- 0.68 ppm). The resulting contents of S(C)S(S)-SAM, S(S)-dcSAM, MTA, Ado and Met in the free-cell supernatant of P. aeruginosa was 56.4 +/- 2.1 nM, 32.2 +/- 2.2 nM, 0.91 +/- 0.10 nM, 19.6 +/- 1.2 nM and 1.93 +/- 0.02 microM (mean +/- SD, n = 4 extractions), respectively. We report also the baseline separation (Rs > or = 1.5) of both diastereoisomeric forms of SAM (S(C)S(S) and S(C)R(S)) and dcSAM (S(S) and R(S)), which can be very useful to establish the relationship between the biologically active versus the inactive species, S(C)S(S)/S(C)R(S) and S(S)/R(S) of SAM and dcSAM, respectively. An additional confirmation of SAM-related metabolites was accomplished by a systematic study of their MS/MS spectra. PMID:19813285

Cataldi, Tommaso R I; Bianco, Giuliana; Abate, Salvatore; Mattia, Daniela

2009-11-01

185

Quadrupole shunt experiments at SPEAR  

SciTech Connect

As part of a program to align and stabilize the SPEAR storage ring, a switchable shunt resistor was installed on each quadrupole to bypass a small percentage of the magnet current. The impact of a quadrupole shunt is to move the electron beam orbit in proportion to the off-axis beam position at the quadrupole, and to shift the betatron tune. Initially, quadrupole shunts in SPEAR were used to position the electron beam in the center of the quadrupoles. This provided readback offsets for nearby beam position monitors, and helped to steer the photon beams with low-amplitude corrector currents. The shunt-induced tune shift measurements were then processed in MAD to derive a lattice model.

Corbett, W.J.; Hettel, R.O.; Nuhn, H.-D.

1996-05-01

186

Origin of Low-Energy Quadrupole Collectivity in Vibrational Nuclei  

SciTech Connect

The coupling of the giant quadrupole resonance to valence-space configurations is shown to be the origin of the formation of low-lying quadrupole-collective structures in vibrational nuclei with symmetric and mixed-symmetric character with respect to the proton-neutron degree of freedom. For the first time experimental evidence for this picture is obtained from electron- and proton scattering experiments on the nucleus {sup 92}Zr that are sensitive to the relative phase of valence-space amplitudes by quantum interference.

Walz, C.; Krugmann, A.; Neumann-Cosel, P. von; Pietralla, N.; Ponomarev, V. Yu.; Scheikh-Obeid, A. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, 64289 Darmstadt (Germany); Fujita, H. [Department of Physics, Osaka University, Toyonaka, Osaka 560-0043 (Japan); iThemba LABS, Post Office Box 722, Somerset West 7129 (South Africa); Wambach, J. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, 64289 Darmstadt (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung, D-64291 Darmstadt (Germany)

2011-02-11

187

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

188

Enhanced quadrupole effects for atoms in optical vortices.  

PubMed

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

Lembessis, V E; Babiker, M

2013-02-22

189

Roles of the sodium-translocating NADH:quinone oxidoreductase (Na+-NQR) on vibrio cholerae metabolism, motility and osmotic stress resistance.  

PubMed

The Na+ translocating NADH:quinone oxidoreductase (Na+-NQR) is a unique respiratory enzyme catalyzing the electron transfer from NADH to quinone coupled with the translocation of sodium ions across the membrane. Typically, Vibrio spp., including Vibrio cholerae, have this enzyme but lack the proton-pumping NADH:ubiquinone oxidoreductase (Complex I). Thus, Na+-NQR should significantly contribute to multiple aspects of V. cholerae physiology; however, no detailed characterization of this aspect has been reported so far. In this study, we broadly investigated the effects of loss of Na+-NQR on V. cholerae physiology by using Phenotype Microarray (Biolog), transcriptome and metabolomics analyses. We found that the V. cholerae ?nqrA-F mutant showed multiple defects in metabolism detected by Phenotype Microarray. Transcriptome analysis revealed that the V. cholerae ?nqrA-F mutant up-regulates 31 genes and down-regulates 55 genes in both early and mid-growth phases. The most up-regulated genes included the cadA and cadB genes, encoding a lysine decarboxylase and a lysine/cadaverine antiporter, respectively. Increased CadAB activity was further suggested by the metabolomics analysis. The down-regulated genes include sialic acid catabolism genes. Metabolomic analysis also suggested increased reductive pathway of TCA cycle and decreased purine metabolism in the V. cholerae ?nqrA-F mutant. Lack of Na+-NQR did not affect any of the Na+ pumping-related phenotypes of V. cholerae suggesting that other secondary Na+ pump(s) can compensate for Na+ pumping activity of Na+-NQR. Overall, our study provides important insights into the contribution of Na+-NQR to V. cholerae physiology. PMID:24811312

Minato, Yusuke; Fassio, Sara R; Kirkwood, Jay S; Halang, Petra; Quinn, Matthew J; Faulkner, Wyatt J; Aagesen, Alisha M; Steuber, Julia; Stevens, Jan F; Hse, Claudia C

2014-01-01

190

Roles of the Sodium-Translocating NADH:Quinone Oxidoreductase (Na+-NQR) on Vibrio cholerae Metabolism, Motility and Osmotic Stress Resistance  

PubMed Central

The Na+ translocating NADH:quinone oxidoreductase (Na+-NQR) is a unique respiratory enzyme catalyzing the electron transfer from NADH to quinone coupled with the translocation of sodium ions across the membrane. Typically, Vibrio spp., including Vibrio cholerae, have this enzyme but lack the proton-pumping NADH:ubiquinone oxidoreductase (Complex I). Thus, Na+-NQR should significantly contribute to multiple aspects of V. cholerae physiology; however, no detailed characterization of this aspect has been reported so far. In this study, we broadly investigated the effects of loss of Na+-NQR on V. cholerae physiology by using Phenotype Microarray (Biolog), transcriptome and metabolomics analyses. We found that the V. cholerae ?nqrA-F mutant showed multiple defects in metabolism detected by Phenotype Microarray. Transcriptome analysis revealed that the V. cholerae ?nqrA-F mutant up-regulates 31 genes and down-regulates 55 genes in both early and mid-growth phases. The most up-regulated genes included the cadA and cadB genes, encoding a lysine decarboxylase and a lysine/cadaverine antiporter, respectively. Increased CadAB activity was further suggested by the metabolomics analysis. The down-regulated genes include sialic acid catabolism genes. Metabolomic analysis also suggested increased reductive pathway of TCA cycle and decreased purine metabolism in the V. cholerae ?nqrA-F mutant. Lack of Na+-NQR did not affect any of the Na+ pumping-related phenotypes of V. cholerae suggesting that other secondary Na+ pump(s) can compensate for Na+ pumping activity of Na+-NQR. Overall, our study provides important insights into the contribution of Na+-NQR to V. cholerae physiology.

Minato, Yusuke; Halang, Petra; Quinn, Matthew J.; Faulkner, Wyatt J.; Aagesen, Alisha M.; Steuber, Julia; Stevens, Jan F.; Hase, Claudia C.

2014-01-01

191

HANLE EFFECT FOR STELLAR DIPOLES AND QUADRUPOLES  

SciTech Connect

We derive exact expressions for the degree of lineal polarization over a resolved or integrated stellar disc due to resonance scattering and the Hanle effect from a dipolar or quadrupolar distribution of magnetic fields. We apply the theory of scattering polarization within the formalism of the spherical tensors representation for the density matrix and radiation field. The distribution of linear polarization over the stellar disk for different configurations of the magnetic field is studied and its topology discussed. For an unresolved dipole, the resulting polarization can be expressed in terms of just three functions (of the inclination angle and effective dipole strength) that are calculated numerically and their behavior discussed. Dipolar and (aligned) quadrupoles are considered in some detail, but the techniques here-in particular, the extensive use of the spherical tensor formalism for polarization-can easily be applied to more general field configurations.

Manso Sainz, R.; Gonzalez, M. J. Martinez [Instituto de Astrofisica de Canarias, Via Lactea s/n, E-38205 La Laguna, Tenerife (Spain)

2012-11-20

192

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

Microsoft Academic Search

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

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

2006-01-01

193

Quadrupole magnets for the SSC  

SciTech Connect

At LBL, we have designed, constructed, and tested ten models (4-1meter, 6-5meter) of the Superconducting Super Collider (SSC) main-ring 5 meter focusing quadrupole magnet (211Tesla/meter). The results of this program are herein summarized.

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

1992-08-01

194

Quadrupole interactions in tetraoxoferrates (VI)  

NASA Astrophysics Data System (ADS)

An applicability of the point charge approach for calculations of quadrupole splittings in Mssbauer spectra of ferrates(VI) was studied. The reasonable correlation between calculated and experimental splittings was observed for the majority of ferrates excepting K3Na(FeO4)2. The comparison of ferrates and chromates was made using calculated nucleus independent coefficient.

Dedushenko, Sergey K.; Perfiliev, Yurii D.; Rusakov, Vyacheslav S.; Gapochka, Alexei M.

2013-05-01

195

LCLS Undulator Quadrupole Fiducialization Plan  

SciTech Connect

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

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

2010-11-24

196

Quadrupole method applied to a thermoelectric leg  

NASA Astrophysics Data System (ADS)

The general principle of the quadrupole formulation is explained particularly via a brief history, the fundamental basis and the quadrupole synthetic representation. Then the heart of the problem is the modelling of a thermoelectric leg. After reminding the governing heat transfer equations, the adequate quadrupole formulation is given in the Laplace domain.

Lazard, M.; Goupil, C.; Fraisse, G.; Scherrer, H.

2012-06-01

197

Defects and hyperfine interactions in Ni Y intermetallics (Y = Al, Ga, In, Ti) via 27Al, 47Ti, 61Ni, 69,71Ga and 115In nuclear resonance  

NASA Astrophysics Data System (ADS)

Defect structures and nuclear electric hyperfine interactions have been investigated in a series of binary Ni-Al, Ni-Ga, Ni-In intermetallic compounds, and the shape memory compound NiTi using 27Al, 47,49Ti, 61Ni, 71Ga and 115In nuclear resonance. Components of the 61Ni NMR spectrum for a series of cubic Ni1-xAlx and Ni1-xGax specimens on either side of x = 0.5 have been identified as due to Ni substitutions and Al (or Ga) vacancies. For stoichiometric NiAl, Ni2Al3 and NiAl3 the 61Ni lines are narrow and distinguished by well-separated Knight shifts, although the 61Ni lineshape for the ordered vacancy compound Ni3Al4 indicates a substantial nuclear quadrupole interaction at the Ni site. The substitution for Al of the group III elements Ga and In, which have isoelectronic outer shells, acts to increase the 61Ni Knight shift such that 61K(Al)<61K(Ga)<61K(In). This trend is observed not only for cubic NiAl and NiGa, but also for trigonal Ni2Al3, Ni2Ga3 and Ni2In3. In NiTi the sharp first-order transition between the (high-temperature) cubic phase and the (low-temperature) monoclinic phase has been observed while monitoring the 61Ni and 49,47Ti NMR lineshapes as a function of temperature. In the non-cubic phases of these materials (including hexagonal egr-NiIn) the electric field gradient tensor components Vzz and eegr at the atomic sites have been determined from the nuclear quadrupole perturbed 27Al, 47Ti, 61Ni, 71Ga NMR lineshapes together with 69Ga and 115In NQR transition frequencies, and compared with values derived from ab initio calculation.

Bastow, T. J.; West, G. W.

2003-12-01

198

Conformational isomerism of methyl dichloroacetate. An infrared, Raman and 35Cl NQR study  

NASA Astrophysics Data System (ADS)

The IR and Raman spectra of methyl dichloroacetate (M-DCA) have been recorded on the liquid, glassy and crystalline states. The vibrational assignment for M-DCA is proposed on the basis of the spectral comparisons between CCl nH 3? n COOCH 3 and CCl nH 5? n CONHCH 5 ( n = 0-3) in the solid state. The observed spectral data indicate that M-DCA exists as a conformational equilibrium in the liquid and in the glassy state and that the conformation in the crystalline state is entirely different from those in the liquid and glassy states. The 35Cl NQR spectrum suggests that the conformation of M-DCA in the crystalline state is the cis form in which one of the two chlorine atoms is located in the cis position with respect to the carbonyl group. Examination of vibrational spectra also leads to the same conclusion.

Mido, Yoshiyuki; Hashimoto, Masao

1985-10-01

199

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

200

Space charge induced nonlinear effects in quadrupole ion traps.  

PubMed

A theoretical method was proposed in this work to study space charge effects in quadrupole ion traps, including ion trapping, ion motion frequency shift, and nonlinear effects on ion trajectories. The spatial distributions of ion clouds within quadrupole ion traps were first modeled for both 3D and linear ion traps. It is found that the electric field generated by space charge can be expressed as a summation of even-order fields, such as quadrupole field, octopole field, etc. Ion trajectories were then solved using the harmonic balance method. Similar to high-order field effects, space charge will result in an "ocean wave" shape nonlinear resonance curve for an ion under a dipolar excitation. However, the nonlinear resonance curve will be totally shifted to lower frequencies and bend towards ion secular frequency as ion motion amplitude increases, which is just the opposite effect of any even-order field. Based on theoretical derivations, methods to reduce space charge effects were proposed. PMID:24385397

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

2014-03-01

201

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

202

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

PubMed

A project to study a new type of acceleration structure has been launched at Peking University, in which a traditional radio frequency quadrupole (RFQ) and a separated function radio frequency quadrupole are coupled in one cavity to accelerate the He+ beam. A helium injector for this project is developed. The injector consists of a 2.45 GHz permanent magnet electron cyclotron resonance ion source and a 1.16 m long low energy beam transport (LEBT). The commissioning of this injector was carried out and an onsite test was held in June 2013. A 14 mA He+ beam with the energy of 30 keV has been delivered to the end of the LEBT, where a diaphragm with the diameter of 7 mm is located. The position of the diaphragm corresponds to the entrance of the RFQ electrodes. The beam emittance and fraction were measured after the 7 mm diaphragm. Its rms emittance is about 0.14 ??mm?mrad and the fraction of He+ is about 99%. PMID:24593446

Peng, Shixiang; Chen, Jia; Ren, Haitao; Zhao, Jie; Xu, Yuan; Zhang, Tao; Zhang, Ailing; Xia, Wenlong; Gao, Shuli; Wang, Zhi; Luo, Yuting; Guo, Zhiyu; Chen, Jia'er

2014-02-01

203

Evidence for the microscopic coexistence of superconductivity and ferromagnetism in UGe2:73Ge-NMR/NQR study  

NASA Astrophysics Data System (ADS)

We report on the pressure-induced novel phases of ferromagnetism and superconductivity (SC) in the itinerant ferromagnet UGe2 via the 73Ge-NQR measurements under pressure ( P). The NQR spectrum has revealed that the ferromagnetic phases are separated into weakly and strongly polarized phases around a critical value of Pc*?1.2 GPa, pointing to a first-order transition around Pc*. Here we present further evidence for the phase separation into ferromagnetic and paramagnetic phases around a critical pressure Pc?1.6 GPa. The measurements of nuclear spin-lattice relaxation rate 1/T1 have probed that SC sets only in the ferromagnetic phase at Tsc?0.2 K, but it does not in the paramagnetic phase.

Harada, A.; Kotegawa, H.; Kawasaki, Y.; Zheng, G.-q.; Kitaoka, Y.; Yamamoto, E.; Haga, Y.; ?nuki, Y.; Itoh, K.; Haller, E. E.

2005-04-01

204

Solid-state NMR/NQR and first-principles study of two niobium halide cluster compounds.  

PubMed

Two hexanuclear niobium halide cluster compounds with a [Nb6X12](2+) (X=Cl, Br) diamagnetic cluster core, have been studied by a combination of experimental solid-state NMR/NQR techniques and PAW/GIPAW calculations. For niobium sites the NMR parameters were determined by using variable Bo field static broadband NMR measurements and additional NQR measurements. It was found that they possess large positive chemical shifts, contrary to majority of niobium compounds studied so far by solid-state NMR, but in accordance with chemical shifts of (95)Mo nuclei in structurally related compounds containing [Mo6Br8](4+) cluster cores. Experimentally determined ?iso((93)Nb) values are in the range from 2400 to 3000ppm. A detailed analysis of geometrical relations between computed electric field gradient (EFG) and chemical shift (CS) tensors with respect to structural features of cluster units was carried out. These tensors on niobium sites are almost axially symmetric with parallel orientation of the largest EFG and the smallest CS principal axes (Vzz and ?33) coinciding with the molecular four-fold axis of the [Nb6X12](2+) unit. Bridging halogen sites are characterized by large asymmetry of EFG and CS tensors, the largest EFG principal axis (Vzz) is perpendicular to the X-Nb bonds, while intermediate EFG principal axis (Vyy) and the largest CS principal axis (?11) are oriented in the radial direction with respect to the center of the cluster unit. For more symmetrical bromide compound the PAW predictions for EFG parameters are in better correspondence with the NMR/NQR measurements than in the less symmetrical chlorine compound. Theoretically predicted NMR parameters of bridging halogen sites were checked by (79/81)Br NQR and (35)Cl solid-state NMR measurements. PMID:24581866

Peri?, Berislav; Gautier, Rgis; Pickard, Chris J; Bosio?i?, Marko; Grbi?, Mihael S; Poek, Miroslav

2014-01-01

205

Stabilized radio-frequency quadrupole  

DOEpatents

A long-vane stabilized radio frequency resonator for accelerating charged particles and including means defining a radio frequency resonator cavity, a plurality of long vanes mounted in the defining means for dividing the cavity into sections, and means interconnecting opposing ones of the plurality of vanes for stabilizing the resonator.

Lancaster, H.D.; Fugitt, J.A.; Howard, D.R.

1982-09-29

206

Laced permanent magnet quadrupole drift tube magnets  

SciTech Connect

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

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

1989-03-01

207

Structurally related non-covalent complexes examined by quadrupole ion trap (QIT) MS2 and infrared multiphoton dissociation Fourier transform ion cyclotron resonance mass spectrometry IRMPD-FT-ICR MS: evidence for salt-bridge structures in the gas phase  

NASA Astrophysics Data System (ADS)

The gas-phase structures of a series of monomeric, homo- and heterodimeric sodium adduct ions of structurally related synthetic compounds Mn [Gua+-NH-(CH2)n-COO-] with n = 1, 2, 3, 5 and Gua = guanidiniocarbonyl pyrrole were investigated by various MS techniques. The compounds Mn are zwitterions in solution and have a strong tendency to aggregate in polar solvents. First, quadrupole ion trap (QIT) collision induced dissociation (CID) product ion experiments with [Mn + Na]+ ions (n = 1, 2, 3, 5) and [arginine + Na]+ were conducted. The fragmentation behavior of the sodium adduct ions provides indirect evidence for a change in structure varying from predominantly charge-solvation of non-ionic molecules (M1, M2 and arginine), to salt-bridge interactions of zwitterionic structures of Mn for n = 3, 5. Second, the sodium affinities ([Delta]HNa+) of the compounds Mn were related to the known literature value of arginine by examination of the CID fragmentation behavior of heterodimer ions [Mn + arginine + Na]+ and [Mn + Mm + Na]+ (n [not equal to] m and n, m = 2, 3, 5) in a QIT. The relative ordering of sodium affinities ([Delta]HNa+): M5 >= arginine > M3 > M2 can be deduced from the relative abundances of [Mn,m + Na]+ and [arg + Na]+ product ions. The maximum sodium affinity of M5 relative to the reference value of arginine strongly supports the assumption of a gas-phase zwitterionic structure. Third, the dimeric sodium adduct ions [2Mn + Na]+ of M2, M3 and M5 dissociate upon IR activation in FT-ICR MS exclusively into the respective monomeric sodium adduct ion [Mn + Na]+. Hence, the establishment of a relative ordering of the gas-phase dissociation energy barriers for the disruption of the non-covalent bond of the complexes by IRMPD-FT-ICR MS was conducted. We find the dimeric complex ion [2M3 + Na]+ more stable than the respective complexes of M2 and M5. Hence, the stability of the examined complex ions [2Mn + Na]+ is obviously strongly determined by the various possible non-covalent interactions between the two respective molecules Mn. The MS study supports the assumption that Mn molecules with n >= 3 are able to conserve zwitterionic structures in the gas phase.

Schfer, Mathias; Schmuck, Carsten; Geiger, Lars; Chalmers, Michael J.; Hendrickson, Christopher L.; Marshall, Alan G.

2004-09-01

208

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

209

Exploration of electronic quadrupole states in atomic clusters by two-photon processes  

NASA Astrophysics Data System (ADS)

We analyse particular two-photon processes as possible means to explore electronic quadrupole states in free small deformed atomic clusters. The analysis is done in the time-dependent local density approximation (TDLDA). It is shown that direct two-photon population (DTP) and off-resonant stimulated Raman (ORSR) scattering can be effectively used for excitation of the quadrupole states in high-frequency (quadrupole plasmon) and low-frequency (infrared) regions, respectively. In ORSR, isolated dipole particle-hole states as well as the tail of the dipole plasmon can serve as an intermediate state. A simultaneous study of low- and high-frequency quadrupoles, combining DTP and ORSR, is most effective. Femtosecond pulses with intensities I = 2 1010 to 2 1011 W cm-2 and pulse durations T = 200-500 fs are found to be optimal. Since the low-lying quadrupole states are dominated by one single electron-hole pair, their energies, being combined with the photoelectron data for hole states, allow us to get the electron spectrum above the Fermi level and thus greatly extend our knowledge on the single-particle spectra of clusters. Besides, the developed schemes allow us to estimate the lifetime of the quadrupole states.

Nesterenko, V. O.; Reinhard, P.-G.; Halfmann, T.; Suraud, E.

2006-09-01

210

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

211

Novel methods for detecting buried explosive devices  

Microsoft Academic Search

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

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

1997-01-01

212

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

213

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

214

QUADRUPOLE BEAM-BASED ALIGNMENT AT RHIC.  

SciTech Connect

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

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

2005-05-16

215

Synchrotron tune adjustment by longitudinal motion of quadrupoles  

Microsoft Academic Search

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

Bertche

1996-01-01

216

Klystron having electrostatic quadrupole focusing arrangement  

DOEpatents

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

Maschke, Alfred W. (East Moriches, NY)

1983-08-30

217

Compact High Gradient Pulsed Magnetic Quadrupole.  

National Technical Information Service (NTIS)

A design for a high gradient, low inductance pulsed quadrupole magnet is presented. The magnet is a circular current dominated design with a circular iron return yoke. Conductor angles are determined by a method of direct multipole elimination which theor...

D. Shuman A. Faltens Y. Kajiyama M. Kireeff-Covo P. Seidl

2005-01-01

218

Klystron having electrostatic quadrupole focusing arrangement  

DOEpatents

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

Maschke, A.W.

1983-08-30

219

Miniature quadrupole mass spectrometer array  

NASA Technical Reports Server (NTRS)

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

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

1998-01-01

220

Miniature quadrupole mass spectrometer array  

NASA Technical Reports Server (NTRS)

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

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

1997-01-01

221

Integrally formed radio frequency quadrupole  

DOEpatents

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

Abbott, Steven R. (Concord, CA)

1989-01-01

222

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

223

Permanent magnet edge-field quadrupole  

DOEpatents

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

Tatchyn, Roman O. (Mountain View, CA)

1997-01-01

224

Evidence for Uniform Coexistence of Ferromagnetism and Unconventional Superconductivity in UGe2: A 73Ge-NQR Study under Pressure  

NASA Astrophysics Data System (ADS)

We report on the itinerant ferromagnetic superconductor UGe2 through 73Ge-NQR measurements under pressure (P). The P dependence of the NQR spectrum signals a first-order transition from the low-temperature (T) and low-P ferromagnetic phase (FM2) to high-T and high-P one (FM1) around a critical pressure of Px 1.2 GPa. The superconductivity exhibiting a maximum value of Tsc=0.7 K at Px 1.2 GPa, was found to take place in connection with the P-induced first-order transition. The nuclear spin-lattice relaxation rate 1/T1 has probed the ferromagnetic transition, exhibiting a peak at the Curie temperature as well as a decrease without the coherence peak below~Tsc. These results reveal the uniformly coexistent phase of ferromagnetism and unconventional superconductivity with a line--node gap. We remark on an intimate interplay between the onset of superconductivity and the underlying electronic state for the ferromagnetic phases.

Kotegawa, H.; Harada, A.; Kawasaki, S.; Kawasaki, Y.; Kitaoka, Y.; Haga, Y.; Yamamoto, E.; ?nuki, Y.; Itoh, K. M.; Haller, E. E.; Harima, H.

2005-02-01

225

N.Q.R measurements of low energy Chiral structures in powdered glassy As2Se3  

NASA Astrophysics Data System (ADS)

Experimental and theoretical work on the As-chalcogen glasses have shown that in the glassy state the local cylindrical symmetry associated with the elemental pyramidal unit is preserved. Here we introduce a local paracrystalline model of glassy As2Se3. This model is based on a tight binding calculation of the electric field gradient (EFG) at the core of an As atom located at the apex of the pyramidal structure. This EFG is shown to be hyper sensitive to the bond angles and bond lengths the As atom forms with the chalcogen nearest neighbors, as well as the hybrid angle formed with second neighbor As atoms. A continuous variation of the bonding parameters produces a unique set of these pyramidal units which are shown to fit the NQR data for powdered glassy samples. The best fit to the NQR data indicates that the pyramidal units organize themselves into Chiral structures in the glass. A plot of the electronic energy per molecular site shows that the chiral structures have on average a lower electronic energy than a random configuration.

Nelson, Chris

2012-02-01

226

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

227

Photodarkening effect in glassy As 2S 3 and As 2O 3  

Microsoft Academic Search

Photodarkening, or the shift of the optical absorption edge to smaller energies after excitation with light whose energy is near that of the optical band edge, has been studied in the chalcogenide glasses for many years. Recently we have conducted high field nuclear magnetic resonance (NMR) studies at 17 T and nuclear quadrupole resonance (NQR) studies of 75As in glassy

P. Hari; S. Guzel; T. Su; P. C. Taylor; P. L. Kuhns; W. G. Moulton; N. S. Sullivan

2003-01-01

228

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

PubMed

A deuteron radio frequency quadrupole (RFQ) accelerator has been designed, fabricated, and tested at BARC, which will be used for neutron generation. The RFQ operates at a frequency of 350 MHz and needs an inter-vane voltage of 44 kV to accelerate the deuteron beam to 400 keV within a length of 1.03 m. The error analysis shows that the offset of two opposite vanes in the same direction by 100 ?m leads to a change in resonant frequency by 1.3 MHz and a significant change of fields in the quadrants (?40% with respect to average field). From the 3D analysis, we have observed that the unwanted dipole mode frequencies are very near to the quadrupole mode frequency which will make structure sensitive to the perturbations. In order to move the dipole modes away from the quadrupole modes, we have used the dipole stabilizer rods. The 5 wire transmission line theory was used to study the perturbative analysis of the RFQ and based on this a computer program has been written to tune the cavity to get required field distribution. Based on these studies, a 1.03 m long RFQ made of OFE copper has been fabricated and tested. Even though the RFQ was designed for deuteron (D(+)) beam, we tested it by accelerating both the proton (H(+)) and D(+) beams. The RFQ was operated in pulsed mode and accelerated both H(+) and D(+) beams to designed values of 200 and 400 keV, respectively. The measured parameters are in good agreement with the designed values validating our simulations and fabrication processes. In this paper, simulations, RF measurements, and beam commissioning results are presented. PMID:24784599

Rao, S V L S; Jain, Piyush; Pande, Rajni; Roy, Shweta; Mathew, Jose V; Kumar, Rajesh; Pande, Manjiri; Krishnagopal, S; Gupta, S K; Singh, P

2014-04-01

229

SUPERCONDUCTING QUADRUPOLE ARRAYS FOR MULTIPLE BEAM TRANSPORT  

SciTech Connect

The goal of this research was to develop concepts for affordable, fully functional arrays of superconducting quadrupoles for multi-beam transport and focusing in heavy ion fusion (HIF)accelerators. Previous studies by the Virtual National Laboratory (VNL) collaboration have shown that the multi-beam transport system (consisting of alternating gradient quadrupole magnets, a beam vacuum system, and the beam monitor and control system) will likely be one of the most expensive and critical parts of such an accelerator. This statement is true for near-term fusion research accelerators as well as accelerators for the ultimate goal of power production via inertial fusion. For this reason, research on superconducting quadrupole arrays is both timely and important for the inertial fusion energy (IFE) research program. This research will also benefit near-term heavy ion fusion facilities such as the Integrated Research Experiment (IRE)and/or the Integrated Beam Experiment (IBX). We considered a 2-prong approach that addresses the needs of both the nearer and longer term requirements of the inertial fusion program. First, we studied the flat coil quadrupole design that was developed by LLNL; this magnet is 150 mm long with a 50 mm aperture and thus is suitable for near term experiments that require magnets of a small length to aperture ratio. Secondly, we studied the novel double-helix quadrupole (DHQ) design in a small (3 x 3) array configuration; this design can provide an important step to the longer term solution of low-cost, easy to manufacture array constructions. Our Phase I studies were performed using the AMPERES magnetostatic analysis software. Consideration of these results led to plans for future magnet R&D construction projects. The first objective of Phase I was to develop the concept of a superconducting focusing array that meets the specific requirements of a heavy ion fusion accelerator. Detailed parameter studies for such quadrupole arrays were performed. Based on these studies, the primary magnet parameters and the general features required for a complete array system (including vacuum and cryostat) were identified. Basic system concepts were formulated to serve as guides for future development work. A related issue was to compare the applicability and benefits of two different magnet technologies for use in such a quadrupole array. Analytical studies were performed for each of the two coil designs, a flat coil based on an HCX quadrupole designed by LLNL and a doublehelix quadrupole designed by AML. These studies have confirmed the feasibility of using either of the two coil designs in a small array.

Rainer Meinke Carl Goodzeit Penny Ball Roger Bangerter

2003-10-01

230

Compressive mass analysis on quadrupole ion trap systems.  

PubMed

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

Chen, Evan Xuguang; Gehm, Michael; Danell, Ryan; Wells, Mitch; Glass, Jeffrey T; Brady, David

2014-07-01

231

Compressive Mass Analysis on Quadrupole Ion Trap Systems  

NASA Astrophysics Data System (ADS)

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

Chen, Evan Xuguang; Gehm, Michael; Danell, Ryan; Wells, Mitch; Glass, Jeffrey T.; Brady, David

2014-05-01

232

Induced CMB quadrupole from pointing offsets  

NASA Astrophysics Data System (ADS)

Recent claims in the literature have suggested that the WMAP quadrupole is not primordial in origin, and arises from an aliasing of the much larger dipole field because of incorrect satellite pointing. We attempt to reproduce this result and delineate the key physics leading to the effect. We find that, even if real, the induced quadrupole would be smaller than the WMAP value. We discuss reasons why the WMAP data are unlikely to suffer from this particular systematic effect, including the implications for observations of point sources. Given this evidence against the reality of the effect, the similarity between the pointing-offset-induced signal and the actual quadrupole then appears to be quite puzzling. However, we find that the effect arises from a convolution between the gradient of the dipole field and anisotropic coverage of the scan direction at each pixel. There is something of a directional conspiracy here the dipole signal lies close to the Ecliptic Plane, and its direction, together with the WMAP scan strategy, results in a strong coupling to the Y2, -1 component in Ecliptic co-ordinates. The dominant strength of this component in the measured quadrupole suggests that one should exercise increased caution in interpreting its estimated amplitude. The Planck satellite has a different scan strategy which does not so directly couple the dipole and quadrupole in this way and will soon provide an independent measurement.

Moss, Adam; Scott, Douglas; Sigurdson, Kris

2011-01-01

233

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

234

Detecting quadrupole interactions in ultracold Fermi gases  

NASA Astrophysics Data System (ADS)

We propose to detect quadrupole interactions of neutral ultracold atoms via their induced mean-field shift. We consider a Mott insulator state of spin-polarized atoms in a two-dimensional optical square lattice. The quadrupole moments of the atoms are aligned by an external magnetic field. As the alignment angle is varied, the mean-field shift shows a characteristic angular dependence, which constitutes the defining signature of the quadrupole interaction. For the 3P2 states of Yb and Sr atoms, we find a frequency shift of the order of tens of Hertz, which can be realistically detected in experiment with current technology. We compare our results to the mean-field shift of a spin-polarized quasi-two-dimensional Fermi gas in continuum.

Lahrz, M.; Lemeshko, M.; Sengstock, K.; Becker, C.; Mathey, L.

2014-04-01

235

Giant quadrupole and monopole resonances in 28Si  

NASA Astrophysics Data System (ADS)

Inelastic alpha scattering measurements have been performed for 28Si at small angles including zero degrees. A total of 66% of the E0 energy-weighted sum rule was identified (using a Satchler version 2 form factor) centered at Ex=17.9 MeV having a width of 4.8 MeV and 34% of the E2 energy-weighted sum rule was identified above Ex=15.3 MeV centered at 19.0 MeV with a width of 4.4 MeV. The dependence of the extracted E0 strength on form factor and optical potential was explored.

Lui, Y.-W.; Bronson, J. D.; Youngblood, D. H.; Toba, Y.; Garg, U.

1985-05-01

236

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

237

Accelerator Magnets:. Dipole, Quadrupole and Sextupole  

NASA Astrophysics Data System (ADS)

The main characteristics of the magnet design and performance of lattice magnets including dipole, quadrupole, and sextupole magnets, will be presented. The design and construction constraints of the conventional, steel iron yoke, and the direct-current magnets are also discussed. The equations of the ideal pole shapes of the dipole, quadrupole, and sextupole, are used to design the magnets. Several two- or three-dimensional calculation codes are introduced to simulate the magnets. Moreover, a brief description of the injection magnets is also presented. Finally, field measurement and mapping methods are introduced and the results from field measurements by means of a Hall probe are discussed.

Hwang, C. S.

2004-02-01

238

Electric quadrupole transition probabilities for atomic lithium  

NASA Astrophysics Data System (ADS)

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

elik, Gltekin; Gke, Yasin; Y?ld?z, Murat

2014-05-01

239

The nuclear electric quadrupole moment of copper.  

PubMed

The nuclear electric quadrupole moment (NQM) of the (63)Cu nucleus was determined from an indirect approach by combining accurate experimental nuclear quadrupole coupling constants (NQCCs) with relativistic Dirac-Coulomb coupled cluster calculations of the electric field gradient (EFG). The data obtained at the highest level of calculation, DC-CCSD-T, from 14 linear molecules containing the copper atom give rise to an indicated NQM of -198(10) mbarn. Such result slightly deviates from the previously accepted standard value given by the muonic method, -220(15) mbarn, although the error bars are superimposed. PMID:24806277

Santiago, Rgis Tadeu; Teodoro, Tiago Quevedo; Haiduke, Roberto Luiz Andrade

2014-06-21

240

SKEW QUADRUPOLE FOCUSING LATTICES AND APPLICATIONS.  

SciTech Connect

In this paper we revisit using skew quadrupole fields in place of traditional normal upright quadrupole fields to make beam focusing structures. We illustrate by example skew lattice decoupling, dispersion suppression and chromatic correction using the neutrino factory Study-II muon storage ring design. Ongoing BNL investigation of flat coil magnet structures that allow building a very compact muon storage ring arc and other flat coil configurations that might bring significant magnet cost reduction to a VLHC motivate our study of skew focusing.

PARKER,B.

2001-06-18

241

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 C17O- and 13CO-labeled species.  

PubMed

We have obtained the oxygen-17 nuclear magnetic resonance (NMR) spectra of a variety of C17O-labeled heme proteins, including sperm whale (Physeter catodon) myoglobin, two synthetic sperm whale myoglobin mutants (His E7----Val E7; His E7----Phe E7), adult human hemoglobin, rabbit (Oryctolagus cuniculus) hemoglobin, horseradish (Cochlearia armoracia) peroxidase (E.C. 1.11.1.7) isoenzymes A and C, and Caldariomyces fumago chloroperoxidase (E.C. 1.11.1.10), in some cases as a function of pH, and have determined their isotropic 17O NMR chemical shifts, delta i, and spin-lattice relaxation times, T1. We have also obtained similar results on a picket fence prophyrin, [5,10,15,20-tetrakis(alpha, alpha, alpha, alpha, alpha-pivalamidophenyl)porphyrinato]iron(II) (1-MeIm)CO, both in solution and in the solid state. Our results show an excellent correlation between the infrared C-O vibrational frequencies, v(C-O), and delta i, between v(C-O) and the 17O nuclear quadrupole coupling constant (e2qQ/h, derived from T1), and as expected between e2qQ/h and delta i. Taken together with the work of others on the 13C NMR of 13CO-labeled proteins, where we find an excellent correlation between delta i(13C) and v(Fe-C), our results suggest that 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 [Li, X.-Y., & Spiro, T.G. (1988) J. Am. Chem. Soc. 110, 6024]. The modulation of this interaction by the local charge field of the distal heme residue (histidine, glutamine, arginine, and possibly lysine) in a variety of species and mutants, as reflected in the NMR and IR measurements, is discussed, as is the effect of cysteine as the proximal heme ligand. PMID:2001365

Park, K D; Guo, K M; Adebodun, F; Chiu, M L; Sligar, S G; Oldfield, E

1991-03-01

242

Stability Regimes in a Rotating Quadrupole Focusing Accelerator.  

National Technical Information Service (NTIS)

A number of high current accelerator designs utilize strong focusing in the form of helical quadrupole and axial guide fields. We obtain a linear dispersion relation for an electron beam propagating in a cylindrical waveguide subject to helical quadrupole...

C. M. Tang F. Mako J. Krall P. Serafim P. Sprangle

1990-01-01

243

Tevatron low-beta quadrupole triplet interconnects  

SciTech Connect

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

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

1992-04-01

244

Hydrogen isotope analysis by quadrupole mass spectrometry  

Microsoft Academic Search

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

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

1981-01-01

245

An ultra-broadband low-frequency magnetic resonance system  

NASA Astrophysics Data System (ADS)

MR probes commonly employ resonant circuits for efficient RF transmission and low-noise reception. These circuits are narrow-band analog devices that are inflexible for broadband and multi-frequency operation at low Larmor frequencies. We have addressed this issue by developing an ultra-broadband MR probe that operates in the 0.1-3 MHz frequency range without using conventional resonant circuits for either transmission or reception. This non-resonant approach significantly simplifies the probe circuit and allows robust operation without probe tuning while retaining efficient power transmission and low-noise reception. We also demonstrate the utility of the technique through a variety of NMR and NQR experiments in this frequency range.

Mandal, S.; Utsuzawa, S.; Cory, D. G.; Hrlimann, M.; Poitzsch, M.; Song, Y.-Q.

2014-05-01

246

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

NASA Astrophysics Data System (ADS)

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

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

247

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

248

Design of a Radiation Resistant Quadrupole Using CICC  

Microsoft Academic Search

High acceptance fragment separators for secondary beam facilities require large aperture quadrupoles close to the production targets. These quadrupoles are exposed to high levels of radiation. We present designs for superferric quadrupoles based on radiation tolerant Cable-In-Conduit-Conductor (CICC) coils that have lifetime limits set by the superconducting materials. CICC coils using both stainless steel and aluminum conduits are described and

A. F. Zeller; J. DeLauter; J. C. DeKamp; J. Bierwagen

2006-01-01

249

Synchrotron tune adjustment by longitudinal motion of quadrupoles.  

National Technical Information Service (NTIS)

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 co...

K. J. Bertche

1996-01-01

250

Giant resonances in 112Sn  

NASA Astrophysics Data System (ADS)

The isoscalar giant quadrupole resonance and the giant monopole resonance in 112Sn were identified at Ex=13.3+/-0.2 MeV and 15.7+/-0.3 MeV, respectively, using small angle inelastic scattering of 129 MeV alpha particles. The nuclear incompressibility parameters for the volume term (Kvol), the surface term (Ksurf), and the symmetry term (Ksym) were determined including 112Sn.

Lui, Y.-W.; Bogucki, P.; Bronson, J. D.; Youngblood, D. H.; Garg, U.

1984-07-01

251

Coexistence of Antiferromagnetism with Superconductivity in CePt2In7: Microscopic Phase Diagram Determined by In115 NMR and NQR  

NASA Astrophysics Data System (ADS)

Single crystals of the heavy-fermion antiferromagnet CePt2In7 with a Nel temperature (TN) of 5.2 K at ambient pressure have been investigated by zero-field In115-nuclear magnetic and quadrupole resonance measurements as a function of applied pressure. Within the antiferromagnetic state, the character of Ce's 4f electron appears to change from localized to itinerantlike at P*2.4 GPa, approximately the pressure where superconductivity first emerges. With increased pressure, the superconducting transition Tc reaches a maximum just at or slightly before antiferromagnetic order disappears, and not at the pressure Pc3.4 GPa, where the steeply decreasing Nel boundary extrapolates to zero temperature. For P >Pc, the spin relaxation rate drops sharply by more than 2 orders of magnitude at Tc, suggestive of a first-order transition.

Sakai, H.; Tokunaga, Y.; Kambe, S.; Ronning, F.; Bauer, E. D.; Thompson, J. D.

2014-05-01

252

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

253

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

254

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

255

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

256

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

257

Observation of quadrupole helix chirality and its domain structure in DyFe3(BO3)4  

NASA Astrophysics Data System (ADS)

Resonant X-ray diffraction (RXD) uses X-rays in the vicinity of a specific atomic absorption edge and is a powerful technique for studying symmetry breaking by motifs of various multipole moments, such as electric monopoles (charge), magnetic dipoles (spin) and electric quadrupoles (orbital). Using circularly polarized X-rays, this technique has been developed to verify symmetry breaking effects arising from chirality, the asymmetry of an object upon its mirroring. Chirality plays a crucial role in the emergence of functionalities such as optical rotatory power and multiferroicity. Here we apply spatially resolved RXD to reveal the helix chirality of Dy 4f electric quadrupole orientations and its domain structure in DyFe3(BO3)4, which shows a reversible phase transition into an enantiomorphic space-group pair. The present study provides evidence for a helix chiral motif of quadrupole moments developed in crystallographic helix chirality.

Usui, T.; Tanaka, Y.; Nakajima, H.; Taguchi, M.; Chainani, A.; Oura, M.; Shin, S.; Katayama, N.; Sawa, H.; Wakabayashi, Y.; Kimura, T.

2014-06-01

258

Observation of quadrupole helix chirality and its domain structure in DyFe3(BO3)4.  

PubMed

Resonant X-ray diffraction (RXD) uses X-rays in the vicinity of a specific atomic absorption edge and is a powerful technique for studying symmetry breaking by motifs of various multipole moments, such as electric monopoles (charge), magnetic dipoles (spin) and electric quadrupoles (orbital). Using circularly polarized X-rays, this technique has been developed to verify symmetry breaking effects arising from chirality, the asymmetry of an object upon its mirroring. Chirality plays a crucial role in the emergence of functionalities such as optical rotatory power and multiferroicity. Here we apply spatially resolved RXD to reveal the helix chirality of Dy 4f electric quadrupole orientations and its domain structure in DyFe3(BO3)4, which shows a reversible phase transition into an enantiomorphic space-group pair. The present study provides evidence for a helix chiral motif of quadrupole moments developed in crystallographic helix chirality. PMID:24705382

Usui, T; Tanaka, Y; Nakajima, H; Taguchi, M; Chainani, A; Oura, M; Shin, S; Katayama, N; Sawa, H; Wakabayashi, Y; Kimura, T

2014-06-01

259

Contribution of electric quadrupole and dipole-quadrupole interference terms in Coulomb breakup of 15C  

NASA Astrophysics Data System (ADS)

The effects of electric quadrupole ( E2) and dipole-quadrupole interference ( E1- E2) terms in the Coulomb breakup of 15C have been investigated within the framework of eikonal approximation. The sensitivity of Coulomb breakup cross section, differential in relative energy and Longitudinal Momentum Distribution (LMD) of core fragments, towards these terms have been examined. A very small (1% of E1) contribution of E2 transition has been predicted in integrated Coulomb breakup cross section. Further it is also found that the inclusion of E2 and E1- E2 terms introduces a small asymmetry in the peak of relative energy spectrum and also increases the peak height of the spectrum. The contribution of dipole-quadrupole interference terms is clearly shown in LMD, as it introduces an asymmetry in the shape of LMD and enhances the matching between the data and predictions.

Singh, P.; Kharb, S.; Singh, M.

2014-02-01

260

Ab initio correlated calculations of rare-gas dimer quadrupoles  

NASA Astrophysics Data System (ADS)

This paper reports ab initio calculations of rare gas ( RG=Kr , Ar, Ne, and He) dimer quadrupoles at the second order of Mller-Plesset perturbation theory (MP2). The study reveals the crucial role of the dispersion contribution to the RG2 quadrupole in the neighborhood of the equilibrium dimer separation. The magnitude of the dispersion quadrupole is found to be much larger than that predicted by the approximate model of Hunt. As a result, the total MP2 quadrupole moment is significantly smaller than was assumed in virtually all previous related studies. An analytical model for the distance dependence of the RG2 quadrupole is proposed. The model is based on the effective-electron approach of Jansen, but replaces the original Gaussian approximation to the electron density in an RG atom by an exponential one. The role of the nonadditive contribution in RG3 quadrupoles is discussed.

Donchev, Alexander G.

2007-10-01

261

ANALYTICAL SOLUTIONS OF SINGULAR ISOTHERMAL QUADRUPOLE LENS  

SciTech Connect

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

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

2013-06-20

262

Noise reduction in negative-ion quadrupole mass spectrometry  

DOEpatents

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

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

1993-01-01

263

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

264

Spacecraft applications of quadrupole mass spectrometry  

NASA Technical Reports Server (NTRS)

Techniques of mass spectrometry are reviewed and the theory of the quadrupole mass spectrometer (QMS) is discussed. The QMS is shown to have several advantages over older types of mass spectrometers. The QMS has been flown on a large number of rockets and several satellites. More sophisticated versions of the QMS are proposed for future satellites. Special emphasis is placed on problems of contamination which are likely to be encountered on a large and complex satellite like the Advanced Technology Satellite ATS-G. The development of a QMS to detect and forestall such contamination is discussed.

Thekaekara, M. P.

1972-01-01

265

Multi-Pass Quadrupole Mass Analyzer  

NASA Technical Reports Server (NTRS)

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

Prestage, John D.

2013-01-01

266

Study of nuclear quadrupole interactions and quadrupole Raman processes of 69Ga and 71Ga in a beta-Ga2O3:Cr3+ single crystal.  

PubMed

Nuclear magnetic resonance (NMR) data and the spin-lattice relaxation times, T(1), of (69)Ga and (71)Ga nuclei in a beta-Ga(2)O(3):Cr(3+) single crystal were obtained using FT NMR spectrometry. Four sets of NMR spectra for (69)Ga (I=3/2) and (71)Ga (I=3/2) were obtained in the crystallographic planes. The (69)Ga and (71)Ga nuclei each had two chemically inequivalent Ga(I) and Ga(II) centers. Each of the (69)Ga and (71)Ga isotopes yielded two different central NMR resonance lines originating from Ga(I) and Ga(II) sites. The nuclear quadrupole coupling constants and asymmetry parameters of (69)Ga(I), (69)Ga(II), (71)Ga(I), and (71)Ga(II) centers in a beta-Ga(2)O(3):Cr(3+) crystal were obtained. Analysis of the EFG tensor principal axes (PAs) for Ga nuclei and the ZFS tensor PAs for the Cr(3+) ion confirmed that the Cr(3+) paramagnetic impurity ion substitutes for the Ga(3+) ion in the oxygen octahedron. In addition, the temperature dependencies of the (69)Ga and (71)Ga relaxation rates were consistent with Raman processes, as T(1)(-1) is proportional to T(2). Even though the Cr(3+) impurities are paramagnetic, the relaxations were dominated by electric quadrupole interactions of the nuclear spins in the temperature range investigated. PMID:19664945

Yeom, Tae Ho; Lim, Ae Ran

2009-10-01

267

LHC interaction region quadrupole cryostat design  

NASA Astrophysics Data System (ADS)

The cryostat of a Large Hadron Collider (LHC) Interaction Region (IR) quadrupole magnet consists of all components of the inner triplet except the magnet assembly itself. It serves to support the magnet accurately and reliably within the vacuum vessel, to house all required cryogenic piping, and to insulate the cold mass from heat radiated and conducted from the environment. It must function reliably during storage, shipping and handling, normal magnet operation, quenches, and seismic excitations, and must be able to be manufactured at low cost. The major components of the cryostat are the vacuum vessel, thermal shield, multi-layer insulation system, cryogenic piping, and suspension system. The overall design of a cryostat for superconducting accelerator magnets requires consideration of fluid flow, proper selection of materials for their thermal and structural performance at both ambient and operating temperature, and knowledge of the environment to which the magnets will be subjected over the course of their expected operating lifetime. This paper describes the current LHC IR inner triplet quadrupole magnet cryostats being designed and manufactured at Fermilab as part of the US-LHC collaboration, and includes discussions on the structural and thermal considerations involved in the development of each of the major systems. .

Nicol, T. H.; Darve, Ch.; Huang, Y.; Page, T. M.

2002-05-01

268

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

269

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

270

Computer simulation of magnetic resonance spectra employing homotopy.  

PubMed

Multidimensional homotopy provides an efficient method for accurately tracing energy levels and hence transitions in the presence of energy level anticrossings and looping transitions. Herein we describe the application and implementation of homotopy to the analysis of continuous wave electron paramagnetic resonance spectra. The method can also be applied to electron nuclear double resonance, electron spin echo envelope modulation, solid-state nuclear magnetic resonance, and nuclear quadrupole resonance spectra. PMID:9799683

Gates, K E; Griffin, M; Hanson, G R; Burrage, K

1998-11-01

271

A quadrupole\\/time-of-flight mass spectrometry study of trp-cages conformation  

Microsoft Academic Search

Trp-cage is a synthetic 20-residue miniprotein that uses tertiary contacts to stabilize its native conformation. NMR, circular\\u000a dichroism (CD), and UV-resonance Raman spectroscopy were used to probe its energy landscape. In this quadrupole\\/time-of-flight\\u000a study, electrospray ionization charge state distribution (CSD) and solution-phase H\\/D exchange are used to probe Trp-cages\\u000a tertiary structure. The CSDs of Trp-cage and its mutant provide spectra

Mingxiang Lin; Zeeshan Ahmed; Christopher R. Taormina; Kasi V. Somayajula

2007-01-01

272

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

273

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

274

Ion-quadrupole effects in ion-molecule collisions.  

NASA Technical Reports Server (NTRS)

Ion-quadrupole effects are investigated via numerical calculations of capture cross sections and computer-plotter studies of ion trajectories in the quadrupole field. Capture cross sections are roughly equal to Langevin values for low rotational temperatures; a large fraction of multiple reflection captures are calculated corresponding to formation of ion-molecule complexes.

Dugan, J. V., Jr.; Palmer, R. W.

1972-01-01

275

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

276

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

277

Feedback damper system for quadrupole oscillations after transition at RHIC.  

SciTech Connect

The heavy ion beam at RHIC undergoes strong quadrupole oscillations just after it crosses transition, which leads to an increase in bunch length making rebucketing less effective. A feedback system was built to damp these quadrupole oscillations and in this paper the characteristics of the system and the results obtained are presented and discussed.

Abreu,N.; Blaskiewicz, M.; Brennan, J.M.; Schultheiss, C.

2008-06-23

278

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

279

Synchrotron Tune Adjustment by Longitudinal Motion of Quadrupoles  

NASA Astrophysics Data System (ADS)

Adjustment of the tune of a synchrotron is generally accomplished by globally varying the strength of 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 this 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 strength of a number of quadrupoles is adjusted. Design philosophies and performance for such phase trombones will be presented. *Operated by Universities Research Association, Inc., under contract with the US. Department of Energy.

Bertsche, K. J.

1996-05-01

280

Novel Phase Transition in CeRu2Al10 Probed by 27Al-NQR/NMR No Evidence of Magnetic Ordering  

NASA Astrophysics Data System (ADS)

The 27Al-NQR/NMR measurements of CeRu2Al10 were carried out to clarify the unusual phase transition at T0=27 K. Distinct NQR peaks associated with five nonequivalent Al sites have been observed at T > T0, and each peak is successfully assigned to their respective Al sites. Below the transition temperature T < T0, each peak simply splits into two peaks except for one site. This indicates that the phase transition is not accompanied by magnetic order, but is presumably associated with the onset of structural transition with lowering symmetry. The nuclear spin-lattice relaxation rate 1/T1 suggests a local moment picture above T* 60 K, and the development of Kondo coherence toward T0. Below T0, 1/T1 shows a gaplike decrease with a gap magnitude of 106 K, being consistent with the macroscopic measurements. The Korringa term below 10 K after the gaplike decrease suggests a gap opening over a portion of the Fermi surface.

Matsumura, Masahiro; Kawamura, Yukihiro; Edamoto, Shingo; Takesaka, Tomoaki; Kato, Harukazu; Nishioka, Takashi; Tokunaga, Yo; Kambe, Shinsaku; Yasuoka, Hiroshi

2009-12-01

281

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

2012-09-01

282

Measurement of a Quadrupole Transition Moment by Interference of Quadrupole and dc-Field-Induced Sum-Frequency Generation  

Microsoft Academic Search

We show that, by measuring the interference between quadrupole and dc-field-induced sum-frequency generation, both the magnitude and the sign of a quadrupole matrix element can be obtained relative to the dipole matrix elements in atomic transitions. We use the measurement of <3s|z2|4d> of sodium to demonstrate the technique.

Donald S. Bethune; Robert W. Smith; Y. R. Shen

1977-01-01

283

An improved integrally formed radio frequency quadrupole  

DOEpatents

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

Abbott, S.R.

1987-10-05

284

Excitation of giant resonances in 208Pb using inelastic 14N scattering  

NASA Astrophysics Data System (ADS)

Inelastic 14N scattering at 266 MeV was used to investigate the giant resonance region in 208Pb. The giant quadrupole resonance is excited quite strongly, but there is no evidence for the excitation of the recently reported 3- and 5- resonances.

Garg, U.; Bogucki, P.; Bronson, J. D.; Lui, Y.-W.; Nagatani, K.; Takada, E.; Takahashi, N.; Tamaya, T.; Youngblood, D. H.

1980-06-01

285

Total correction of parasitic sextupole components in magnetic quadrupole lenses  

NASA Astrophysics Data System (ADS)

The presence of parasitic sextupole components in magnetic quadrupole lenses is a serious limitation to nuclear microprobe resolution. Earlier measurements of the parasitic sextupole component and the correction to below 0.15% of the quadrupole field strength using the rotating coil technique was initially limited by interference from the quadrupole component. An improvement of the technique has now been devised and used to reduce the parasitic sextupole component to 0.02%. The reduction has been confirmed using the shadow image technique, and improved resolution has been measured with the sextupole fields reduced.

Breese, M. B. H.; Jamieson, D. N.; Cookson, J. A.

1991-03-01

286

Electric quadrupole transition probabilities and line strengths of Ti11+  

NASA Astrophysics Data System (ADS)

Electric quadrupole transition probabilities and line strengths have been calculated using the weakest bound electron potential model for sodium-like titanium, considering many transition arrays. We employed numerical Coulomb approximation and non-relativistic Hartree-Fock wavefunctions for the expectation values of radii in determination of parameters of the model. The necessary energy values have been taken from experimental data in the literature. The calculated electric quadrupole line strengths have been compared with available data in the literature and good agreement has been obtained. Moreover, some electric quadrupole transition probability and line strength values not existing in the literature for some highly excited levels have been obtained using this method.

Gke, Yasin; elik, Gltekin; Y?ld?z, Murat

2014-07-01

287

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

NASA Astrophysics Data System (ADS)

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 14N 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 14N 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 14N 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 14N 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.

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

2011-06-01

288

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

2011-06-01

289

Electro-Magnetic Quadrupole Magnets in the LCLS FEL Undulator  

SciTech Connect

We discuss various aspects of electro-magnetic quadrupole (EMQ) magnets for the LCLS FEL undulator, including their utility in beam-based alignment (BBA), magnet design issues, and impact on tunnel environment, reliability, and cost.

Emma, P.

2005-01-31

290

New devices for the magnetic center location of quadrupole magnets.  

National Technical Information Service (NTIS)

A system is presently under development at SACLAY for determining the location of the magnetic center of superconducting quadrupole magnets. It uses magnetic crystals in garnet film form, with visualization of the results by an optical method. This paper ...

J. Le Bars F. Kircher

1992-01-01

291

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

292

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

293

Alignment tolerances of IR quadrupoles in the LHC  

SciTech Connect

Luminosity in the LHC will depend critically on the alignment of the triplet quadrupoles. These quadrupoles are closest to the interaction points (IPs), have large gradients and the {beta} functions have their largest values within these quadrupoles. Within a triplet, the cold masses of the Q1 and Q3 quadrupoles will be housed in separate cryostats while Q2a and Q2b will be placed in a single cryostat. The absolute alignments of Q1, Q3 and the Q2a/Q2b pair with respect to the desired axes will be determined during installation. The relative alignment of Q2a and Q2b however will be fixed once they are placed in their common cryostat at Fermilab. In this note, we examine the required relative alignment tolerances of Q2a and Q2b. An early study of some alignment tolerances was done by Weisz [1].

Tanaji Sen

1999-11-05

294

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

295

PRINCIPLE OF SKEW QUADRUPOLE MODULATION TO MEASURE BETATRON COUPLING.  

SciTech Connect

The measurement 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 different skew quadrupole families the two eigentunes are precisely measured with the phase lock loop system. The projections of the residual coupling coefficient onto the skew quadrupole coupling modulation directions are determined. The residual linear coupling could be corrected according to the measurement. An analytical solution for skew quadrupole modulation based on Hamiltonian perturbation approximation is given, and simulation code using smooth accelerator model is also developed. Some issues concerning the practical applications of this technique are discussed.

LUO.Y.PILAT,F.ROSER,T.ET AL.

2004-07-05

296

Autonomously Calibrating a Quadrupole Mass Spectrometer  

NASA Technical Reports Server (NTRS)

A computer program autonomously manages the calibration of a quadrupole ion mass spectrometer intended for use in monitoring concentrations and changes in concentrations of organic chemicals in the cabin air of the International Space Station. The instrument parameters calibrated include the voltage on a channel electron multiplier, a discriminator threshold, and an ionizer current. Calibration is achieved by analyzing the mass spectrum obtained while sweeping the parameter ranges in a heuristic procedure, developed by mass spectrometer experts, that involves detection of changes in signal trends that humans can easily recognize but cannot necessarily be straightforwardly codified in an algorithm. The procedure includes calculation of signal-to-noise ratios, signal-increase rates, and background-noise-increase rates; finding signal peaks; and identifying peak patterns. The software provides for several recovery-from-error scenarios and error-handling schemes. The software detects trace amounts of contaminant gases in the mass spectrometer and notifies associated command- and-data-handling software to schedule a cleaning. Furthermore, the software autonomously analyzes the mass spectrum to determine whether the parameters of a radio-frequency ramp waveform are set properly so that the peaks of the mass spectrum are at expected locations.

Lee, Seungwon; Bornstein, Benjamin J.

2009-01-01

297

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

NASA Astrophysics Data System (ADS)

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

Pati, Ranjit

298

An introduction to quadrupole-time-of-flight mass spectrometry  

Microsoft Academic Search

A brief introduction is presented to the basic principles and application of a quadrupole-time-of-flight (TOF) tandem mass spectrometer. The main features of reflecting TOF instruments with orthogonal injection of ions are discussed. Their operation and performance are compared with those of triple quadrupoles with electrospray ionization and matrix-assisted laser desorption\\/ionization (MALDI) TOF mass spectrometers. Examples and recommendations are provided for

Igor V. Chernushevich; Alexander V. Loboda; Bruce A. Thomson

2001-01-01

299

Do we need to correct the internal linear combination quadrupole?  

NASA Astrophysics Data System (ADS)

The problem of high correlation of the CMB quadrupole with foregrounds is investigated in this paper. We present an analysis of the cross-correlation for the WMAP ILC(III) low multipoles and foregrounds and show that without correction of the sign for m = 0 harmonic of the quadrupole this correlation is very high. By analysis of 104 Monte Carlo simulations of the CMB-foreground separation, presented by Eriksen et al. [1], we show that practically for 50% realizations of the CMB quadrupole with the sign of the m = 0 mode equivalent to the sign of the foreground component, the input quadrupoles have the opposite sign of the output signal. Preserving the WMAP ILC(III) power spectrum of the quadrupole and changing the sign of the ILC (III) m = 0mode, we get the coefficient of cross-correlations | K( ? = 2)| < 10%, what decreases the level of cross-correlations by a factor of 5 6. We use themultipole vectors for the renormalized ILC(III) quadrupole and show that these vectors are very sensitive to the sign and amplitude of the m = 0 mode.

Naselsky, P. D.; Verkhodanov, O. V.

2007-09-01

300

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

301

Gamma decay of isoscalar and isovector giant resonances following heavy-ion inelastic scattering  

SciTech Connect

Results from studies of gamma decay of giant resonances in /sup 208/Pb and /sup 90/Zr following inelastic excitation by 22 and 84 MeV/nucleon /sup 17/O ions are presented. Data on ground state decay of isoscalar giant quadrupole and isovector giant dipole resonances are presented and compared with calculations. Decays from resonances to low lying excited states are also discussed. Preliminary results from an attempt to isolate the isovector quadrupole resonance in /sup 208/Pb using its gamma decay are presented.

Beene, J.R.; Varner, R.L.; Bertrand, F.E.

1987-01-01

302

Isotope ratio of Cl NQR spin-lattice relaxation times in 1D hydrogen-bonding system of tetramethylpyrazine-chloranilic acid at high temperatures  

NASA Astrophysics Data System (ADS)

The temperature dependences of spin-lattice relaxation time T 1 of 35Cl and 37Cl NQR were studied for the co-crystal of tetramethylpyrazine (TMP) with chloranilic acid (H2ca), TMP-H2ca, in which one-dimensional hydrogen bonding is formed by alternate arrangement of TMP and H2ca. The isotope ratio 37Cl T 1 / 35Cl T 1 was determined to be 1.0 0.1 above ca. 290 K where a steep decrease of spin-lattice relaxation time T 1 with increasing temperature was observed. In this temperature range it is suggested that the relaxation is originated from the slow fluctuation of electric field gradient (EFG). Beside EFG fluctuation due to the external-charge-density fluctuation, the small angle reorientation of the quantization axis triggered by a proton transfer motion between N...H-O and N-H...O hydrogen bonding states is proposed.

Asaji, Tetsuo

2013-05-01

303

Quadrupole Contributions to London's Dispersion Forces  

Microsoft Academic Search

The contribution of terms in R8 and R10 to the dispersion forces is expressed by a simple, approximate formula (Eq. (7)) involving only measurable quantities (polarizability, absorption frequency, oscillator strength). The formula is applicable when the dispersion curve of the substance can be represented with the use of a single resonant frequency. Numerical values of the terms in question are

Henry Margenau

1938-01-01

304

Spectroscopic Monte Carlo Calculation with the Monopole Plus Quadrupole Pairing Plus Quadrupole Interaction for 170Yb  

NASA Astrophysics Data System (ADS)

The Spectroscopic Monte Carlo Method is applied to the nucleus {}170Yb using the Monopole plus Quadrupole Pairing plus Quadrupole interaction for yrast states up to J? =12+. The unusually small statistical errors in the Monte Carlo calculations of the yrast energies (? 40div 70KeV) despite moderately strong sign oscillations, are discussed. Energy levels, expectation values of pairing potential and the pairing strength to J=12 for the neutron intruder orbit and to J=10 for the proton intruder orbit are evaluated. It is shown that the Hartree-Fock-Bogoliubov wave functions obtained with variation after projection to good particle number and to good z-component of the angular momentum and reprojected to good J2,Jz after variation, give excitation energies in reasonable agreement with the Monte Carlo values. The intrinsic HFB wave functions have a considerable angular momentum dependence. Wave functions which are projected to good angular momentum after variation (PAV), lead to excitation energies larger than the corresponding Monte Carlo values.

Puddu, G.

2004-08-01

305

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

306

Optimization of a commercial quadrupole mass spectrometer for time-of-flight measurements of laser desorption  

NASA Astrophysics Data System (ADS)

Quadrupole mass analyzers (QMAs) are receiving increasing attention for applications in time-of-flight (TOF) studies of laser-induced desorption, ablation and surface reactions in order to extend the information attainable from these experiments. With such a complicated detection device, however, it is easily possible to inadvertantly manipulate the real time-of-flight distribution, for example by missing fast or slow particles. In this work a systematic investigation of the influence of the different QMA parameters on the signal and their interplay was undertaken in laser-induced desorption experiments. The particle pulses were generated by resonant vibrational excitation of condensed benzene films with a TEA CO2 laser. Our investigations give the optimized configuratioin and setting of potentials for the instrument studied, in terms of sensitivity and energy resolution, and an accurate procedure to determine the drift time of ions in the quadrupole. This makes it possible to detect undistorted time-of-flight distributions with a time resolution of about 5 [mu]s for a range of incident kinetic energies of at least 0-3 eV.

Braun, R.; Hess, P.

1993-06-01

307

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

308

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

309

Higher Order Parametric Excitation Modes for Spaceborne Quadrupole Mass Spectrometers  

NASA Technical Reports Server (NTRS)

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.

2011-01-01

310

Nuclear magnetic resonances in (In,Ga)As/GaAs quantum dots studied by resonant optical pumping  

NASA Astrophysics Data System (ADS)

The photoluminescence polarizations of (In,Ga)As/GaAs quantum dots annealed at different temperatures are studied as a function of external magnetic field (Hanle curves). In these dependencies, remarkable resonant features appear due to all-optical nuclear magnetic resonances (NMR) for optical excitation with modulated circular polarization. Application of an additional radio-frequency field synchronously with the polarization modulation strongly modifies the NMR features. The resonances can be related to transitions between different nuclear spin states split by the strain-induced gradient of the crystal field and by the externally applied magnetic field. A theoretical model is developed to simulate quadrupole and Zeeman splittings of the nuclear spins in a strained quantum dot. Comparison with the experiment allows us to uniquely identify the observed resonances. The large broadening of the NMR resonances is attributed to variations of the quadrupole splitting within the quantum dot volume, which is well described by the model.

Kuznetsova, M. S.; Flisinski, K.; Gerlovin, I. Ya.; Petrov, M. Yu.; Ignatiev, I. V.; Verbin, S. Yu.; Yakovlev, D. R.; Reuter, D.; Wieck, A. D.; Bayer, M.

2014-03-01

311

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

312

Gaussian overlap approximation for the quadrupole collective states  

NASA Astrophysics Data System (ADS)

The generator coordinate method in the Gaussian overlap approximation (GOA) is applied to a description of the nuclear quadrupole collective states. The full five-dimensional quadrupole tensor is used as a set of the generator coordinates. The integral Hill-Wheeler equation is reduced to a differential equation by using the Fourier transforms of the overlap and energy kernels. The differential Bohr Hamiltonian obtained this way is compared with that derived by the usual approach to the collective Hamiltonian in the GOA which does contain an additional approximation. The method of calculating the quantities which determine the Bohr Hamiltonian from the set of deformation-dependent intrinsic states is demonstrated. In particular, it appears that the moments of inertia at the quadrupole rotations are of the Yoccoz type.

Rohozi?ski, Stanis?aw G.

2012-09-01

313

Ion dynamics in non-perfect quadrupole traps  

NASA Astrophysics Data System (ADS)

Ion dynamics in non-perfect quadrupole traps differ from those in a pure quadrupole field. We obtain an analytic expression for a quadrupole field superimposed with weak, higher-order multipole fields. Single ion dynamics in such trapping fields close to the instability point are investigated. We show that for an in-phase octopole field, oscillating envelopes of the axial displacement grow exponentially with the parameter deviation; whereas for an out-of-phase octopole field the growth of the oscillating envelopes follows a square-root law. A hard-sphere scattering model is assumed to incorporate collisions with buffer-gas molecules. The collision frequency and cross-section are defined. A simulation algorithm for many-ion dynamics is developed based on the Verlet algorithm and Monte Carlo techniques. We show how a weak octopole field affects the mass resolution in a significant way.

Wu, Xiao-Guang

2007-05-01

314

Variable-field permanent magnet quadrupole for the SSC  

SciTech Connect

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

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

1993-10-01

315

Calculations on permanent-magnet quadrupoles with nonrectangular cross section  

SciTech Connect

The current trend toward higher frequencies to power drift-tube linacs (DTLs) and coupled-cavity linacs (CCLs) reduces the space available for quadrupole focusing magnets. Similarly, the space available for matching sections between linac sections is limited, and often the matching section bunchers are designed in odd shapes to make them fit. This shaping further restricts focusing magnet space. One approach to attaining sufficient quadrupole strength is such situations is to use rare-earth permanent-magnet quadrupoles (PMQs) with cross sections tailored to fill as much of the available space as possible. In this paper, we describe some techniques we have developed to calculate the properties of such magnets both singly and when other magnets are nearby. 3 refs., 4 figs.

Boicourt, G.P.; Merson, J.L.

1988-01-01

316

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)] [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)] [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)] [Physics Department, Royal Holloway, University of London, Egham, Surrey TW20 0EX (United Kingdom)

1998-08-01

317

Vane coupling rings: a simple technique for stabilizing a four-vane radiofrequency quadrupole structure  

SciTech Connect

The benefits of stabilized accelerating structures, with regard to the manufacture and operation, have been well documented. The four-vane radiofrequency quadrupoles (RFQ) presently being designed and constructed in many laboratories are not stabilized because of the weak electromagnetic coupling between the quadrant resonators. This paper presents a simple technique developed at the Lawrence Berkeley Laboratory using vane coupling rings (VCR's) which azimuthally stabilize the RFQ structure and greatly enhance its use as a practical accelerator. In particular, the VCR's: completely eliminate the dipole modes in the frequency range of interest; provide adequate quadrant balance with an initial precision mechanical alignment of the vanes; and enhance axial balance and simplify end tuners. Experimental verification tests on a scale model are discussed.

Howard, D.; Lancaster, H.

1982-11-01

318

{open_quotes}Quadrupoled{close_quotes} materials for second-order nonlinear optics  

SciTech Connect

We describe a new approach to second-order nonlinear optical materials, namely quadrupoling. This approach is valid in the regime of Kleinman (full permutation) symmetry breaking, and thus requires a two- or three dimensional microscopic nonlinearity at wavelengths away from material resonances. This {open_quotes}quadrupolar{close_quotes} nonlinearity arises from the second rank pseudotensor of the rotationally invariant representation of the second-order nonlinear optical tensor. We have experimentally investigated candidate molecules comprised of chiral camphorquinone derivatives by measuring the scalar invariant associated with the rank two pseudotensor using hyper-Rayleigh scattering. We have found sizable scalar figures of merit for several compounds using light for which the second harmonic wavelengths are greater than 100 nm longer than the absorption peak location. At these wavelengths, the quadrupolar scalar is as large as the polar (EFISH) scalar of p-nitroaniline. Prospects for applications are discussed.

Hubbard, S.F.; Petschek, R.G.; Singer, K.D. [Case Western Reserve Univ., Cleveland, OH (United States). Dept. of Physics] [and others

1997-10-01

319

Splitting of the Giant Monopole Resonance with Deformation in Sm Nuclei  

NASA Astrophysics Data System (ADS)

In (?,?') measurements on spherical 144Sm and deformed 154Sm, the cross sections and energies of the two components of the isoscalar giant resonance are found to be consistent with a splitting of the giant monopole resonance in 154Sm into two components of roughly equal strength. One component remains close to the giant-monopole-resonance energy of 144Sm while the second is coincident with the giant quadrupole resonance. This is shown to be consistent with simple schematic-model predictions.

Garg, U.; Bogucki, P.; Bronson, J. D.; Lui, Y.-W.; Rozsa, C. M.; Youngblood, D. H.

1980-11-01

320

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

321

3d Electron Quadrupole Moments in Vanadium Oxides  

NASA Astrophysics Data System (ADS)

We report the local spin susceptibility and the 3d quadrupole moment in V5O9. The metal-insulator transition accompanies with the spin singlet formation without an apparent dimerization in the V lattice. Based on the angle dependence of the 51V quadrupole frequency, we suggest that the orbital ordering assists the spin singlet formation in the quasi-one-dimensional chain in V5O9. At high temperatures, the paramagnetic metallic state has nonuniform spin susceptibility depending on V sites, which indicates that the magnetically active and inactive V sites are already separated in the metallic state due to the strong electron correlation.

Jin-no, Taka; Aoyama, Satoshi; Shimizu, Yasuhiro; Itoh, Masayuki; Ueda, Yutaka

2012-12-01

322

High and ultra-high gradient quadrupole magnets  

NASA Astrophysics Data System (ADS)

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

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

1985-05-01

323

Simultaneous quadrupole and octupole shape phase transitions in Thorium  

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

324

Cavity Resonators.  

National Technical Information Service (NTIS)

The microwave cavity resonator may be used in the field of electron spin resonance spectroscopy for studying samples of paramagnetic materials which are supported within the resonator. The resonator passes a maximum amount of light through the walls to th...

E. L. Cochran

1965-01-01

325

Stochastic Resonance  

NASA Astrophysics Data System (ADS)

Preface; 1. Introduction and motivation; 2. Stochastic resonance: its definitions, history and debates; 3. Stochastic quantization; 4. Suprathreshold stochastic resonance: encoding; 5. Suprathreshold stochastic resonance: large N encoding; 6. Suprathreshold stochastic resonance: decoding; 7. Suprathreshold stochastic resonance: large N decoding; 8. Optimal stochastic quantization; 9. SSR, neural coding, and performance tradeoffs; 10. Stochastic resonance in the auditory system; 11. The future of stochastic resonance and suprathreshold stochastic resonance; Appendices; References; Index.

McDonnell, Mark D.; Stocks, Nigel G.; Pearce, Charles E. M.; Abbott, Derek

2012-10-01

326

Indirect (J) coupling of inequivalent ^75As nuclei in crystalline and glassy As_2Se3 and As_2S_3  

NASA Astrophysics Data System (ADS)

Indirect nuclear spin-spin couplings, or J couplings, were first observed in liquids using nuclear magnetic resonance (NMR) techniques [1]. Because of the nature of the quadrupole Hamiltonian in pure nuclear quadrupole resonance (NQR) experiments J couplings should be observable between inequivalent nuclei [2]. We present results of ^75As NQR measurements in crystalline and glassy As_2S3 and As_2Se_3. These ^75As NQR measurements were performed at various frequencies between about 55 and 75 MHz. The NQR frequency is determined by the electric field gradient (EFG) at the nucleus, and in these materials there are two non-equivalent sites in each of the two crystals. The J coupling can occur through several chemical bonds, and in our case this coupling must go through two As-S covalent bonds since the nearest neighbor As sites are separated by chalcogen atoms. Instead of the monotonic decay expected from relaxation spin-spin theory, the decays of the NQR Hahn echoes following a 90^0-180^0pulse sequence exhibit damped oscillations superimposed on an exponential decay. These damped oscillations can be explained by an indirect coupling (J coupling). Experimental values of the J couplings were obtained from the periods of the oscillations and calculations of the most probable transitions using 2^nd order perturbation theory. The value estimated by this method for the ^2J(^75As-S-^75As) in crystalline As_2S3 compares well with empirical estimates, which are obtained using an existing value of ^2J(^31P-S-^31P) and known scalings with atomic number from the literature. 1. E. L. Hahn and D. E Maxwell, Phys. Rev. 84, 1246 (1951). 2. T. P. Das and E. L. Hahn, Solid State Physics, supp 1, Nuclear Quadrupole Resonance Spectroscopy, p. 28, Academic Press 1958.

Whitaker, J.; Ahn, E.; Hart, P.; Williams, G. A.; Taylor, P. C.; Facelli, J. C.

2004-03-01

327

A simple microscopic approach for the study of giant resonances  

Microsoft Academic Search

A simple approach for the description of monopole and quadrupole giant resonances of light nuclei in the framework of the generator coordinate method is proposed. Various effective forces, including recent Skyrme force parametrizations, have been used. Excitation energies, transition matrix elements and densities, sum rules and collective wave functions are presented and discussed.

D. E. Medjadi; P. Quentin

1985-01-01

328

A correction scheme for the quadrupole misalignment errors in the ANL--APS positron linac  

SciTech Connect

The Argonne Advanced Photon Source (APS) positron linac contains 24 quadrupoles of which 22 are configured as a FODO system and are distributed along the last 7 constant gradient accelerating structures. Errors in quadrupole and waveguide positions deflect the positron beam centroid, contributing to the aperture requirements in the accelerating structures and quadrupoles. A correction scheme using correction dipole magnets is proposed to compensate for the random errors in quadrupoles.

Nassiri, A.

1992-01-01

329

A correction scheme for the quadrupole misalignment errors in the ANL--APS positron linac  

SciTech Connect

The Argonne Advanced Photon Source (APS) positron linac contains 24 quadrupoles of which 22 are configured as a FODO system and are distributed along the last 7 constant gradient accelerating structures. Errors in quadrupole and waveguide positions deflect the positron beam centroid, contributing to the aperture requirements in the accelerating structures and quadrupoles. A correction scheme using correction dipole magnets is proposed to compensate for the random errors in quadrupoles.

Nassiri, A.

1992-12-31

330

Optical quadrupole sum-frequency generation in sodium vapor  

Microsoft Academic Search

We show that second-order coherent sum-frequency generation via quadrupole transitions in metal vapors can be easily detected. The process is as strong as the allowed third-order processes. Our experimental results agree very well with theoretical predictions. (AIP)

D. S. Bethune; R. W. Smith; Y. R. Shen

1976-01-01

331

Optical Quadrupole Sum-Frequency Generation in Sodium Vapor  

Microsoft Academic Search

We show that second-order coherent sum-frequency generation via quadrupole transitions in metal vapors can be easily detected. The process is as strong as the allowed third-order processes. Our experimental results agree very well with theoretical predictions.

D. S. Bethune; R. W. Smith; Y. R. Shen

1976-01-01

332

Quadrupole-octupole coupling in the light actinides  

NASA Astrophysics Data System (ADS)

The relevance of coupling of quadrupole and octupole collective degrees of freedom in physical observables is explored in calculations with the Gogny force for the light radon, radium, and thorium isotopes. The results of the generator coordinate method calculations for the properties of negative parity states show an improvement over the traditional ones that consider just the octupole moment.

Robledo, L. M.; Butler, P. A.

2013-11-01

333

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

ScienceCinema

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

Giorgio Ambrosio

2010-01-08

334

Propagation Hanle effect of quadrupole polaritons in Cu2O  

Microsoft Academic Search

The 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 5 + ? level in 2 CuO crystal give rise to the propagation Hanle

S. A. Moskalenko; M. A. Liberman

2002-01-01

335

Operational Aspects of the Main Injector Large Aperture Quadrupole (WQB).  

National Technical Information Service (NTIS)

A two-year Large Aperture Quadrupole (WQB) Project was completed in the summer of 2006 at Fermilab. Nine WQBs were designed, fabricated and bench-tested by the Technical Division. Seven of them were installed in the Main Injector and the other two for spa...

B. Brown D. Capista J. Crisp L. Bartelson W. Chou

2006-01-01

336

Application of switched-power techniques to quadrupoles  

SciTech Connect

Electric fields on the order of 1 GV/m may be achievable with very short (few ps) pulses. A field of 0.3 GV/m is equivalent in deflecting strength to a magnetic field of 1 Tesla. We consider here the possibility of replacing magnets (specifically final focus quadrupoles) with laser-switched devices. 7 refs., 3 figs.

Aronson, S.H.; Fernow, R.C.

1988-01-01

337

Continuous cell separation using novel magnetic quadrupole flow sorter  

Microsoft Academic Search

A laboratory prototype of a flow cell sorter based on magnetic quadrupole field was built and evaluated. The magnetic force acting on magnetically labeled cells in such a field has a `centrifugal character which provides a basis for the design of a continuous separation process. The sorter was tested on a model cell system of human peripheral lymphocytes labeled with

Maciej Zborowski; Liping Sun; Lee R Moore; P Stephen Williams; Jeffrey J. Chalmers

1999-01-01

338

Driving a quadrupole mass spectrometer via an isolating stage  

NASA Technical Reports Server (NTRS)

Driving a quadrupole mass spectrometer includes obtaining an air core transformer with a primary and a secondary, matching the secondary to the mass spectrometer, and driving the primary based on first and second voltage levels. Driving of the primary is via an isolating stage that minimizes low level drive signal coupling.

Chutjian, Ara (Inventor); Aalami, Dean (Inventor); Darrach, Murray (Inventor); Orient, Otto (Inventor)

2002-01-01

339

High and Ulta-High Gradient Quadrupole Magnets.  

National Technical Information Service (NTIS)

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 a...

W. O. Brunk D. R. Walz

1985-01-01

340

Large energy-spread beam diagnostics through quadrupole scans  

NASA Astrophysics Data System (ADS)

The Facility for Advanced Accelerator and Experimental Tests (FACET) is a new user facility at the SLAC National Accelerator Laboratory, servicing next-generation accelerator experiments. The 1.5% RMS energy spread of the FACET beam causes large chromatic aberrations in optics. These aberrations necessitate updated quadrupole scan fits to remain accurate.

Frederico, Joel; Adli, Erik; Hogan, Mark; Raubenheimer, Tor

2012-12-01

341

Quadrupole transport experiment with space charge dominated cesium ion beam  

SciTech Connect

The purpose of the experiment is to investigate the beam current transport limit in a long quadrupole-focussed transport channel in the space charge dominated region where the space charge defocussing force is almost as large as the average focussing force of the channel.

Faltens, A.; Keefe, D.; Kim, C.; Rosenblum, S.; Tiefenback, M.; Warwick, A.

1984-08-01

342

Super strong permanent magnet quadrupole for a linear collider  

Microsoft Academic Search

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

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

2004-01-01

343

Dispersion interactions between atoms involving electric quadrupole polarizabilities  

Microsoft Academic Search

Retarded van der Waals forces involving electric quadrupole polarizabilities are investigated in detail in order to resolve the recently published conflicting predictions of the forms of dispersion potentials. One of the predictions was based on an approximate evaluation of the energies obtained from dispersion theory techniques. These techniques avoided explicit reference to the detailed structure of the individual systems. In

E. A. Power; T. Thirunamachandran

1996-01-01

344

Skew quadrupole in RHIC dipole magnets at high fields  

Microsoft Academic Search

In the RHIC are 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

A. Jain; R. Gupta; P. Thompson; P. Wanderer

1996-01-01

345

Status of the LHC inner triplet quadrupole program at Fermilab  

Microsoft Academic Search

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

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

2001-01-01

346

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

347

Targeted proteomic quantification on quadrupole-orbitrap mass spectrometer.  

PubMed

There is an immediate need for improved methods to systematically and precisely quantify large sets of peptides in complex biological samples. To date protein quantification in biological samples has been routinely performed on triple quadrupole instruments operated in selected reaction monitoring mode (SRM), and two major challenges remain. Firstly, the number of peptides to be included in one survey experiment needs to be increased to routinely reach several hundreds, and secondly, the degree of selectivity should be improved so as to reliably discriminate the targeted analytes from background interferences. High resolution and accurate mass (HR/AM) analysis on the recently developed Q-Exactive mass spectrometer can potentially address these issues. This instrument presents a unique configuration: it is constituted of an orbitrap mass analyzer equipped with a quadrupole mass filter as the front-end for precursor ion mass selection. This configuration enables new quantitative methods based on HR/AM measurements, including targeted analysis in MS mode (single ion monitoring) and in MS/MS mode (parallel reaction monitoring). The ability of the quadrupole to select a restricted m/z range allows one to overcome the dynamic range limitations associated with trapping devices, and the MS/MS mode provides an additional stage of selectivity. When applied to targeted protein quantification in urine samples and benchmarked with the reference SRM technique, the quadrupole-orbitrap instrument exhibits similar or better performance in terms of selectivity, dynamic range, and sensitivity. This high performance is further enhanced by leveraging the multiplexing capability of the instrument to design novel acquisition methods and apply them to large targeted proteomic studies for the first time, as demonstrated on 770 tryptic yeast peptides analyzed in one 60-min experiment. The increased quality of quadrupole-orbitrap data has the potential to improve existing protein quantification methods in complex samples and address the pressing demand of systems biology or biomarker evaluation studies. PMID:22962056

Gallien, Sebastien; Duriez, Elodie; Crone, Catharina; Kellmann, Markus; Moehring, Thomas; Domon, Bruno

2012-12-01

348

The phase diagrams and doped-hole segregation in La{sub 2}CuO{sub 4+{delta}} and La{sub 2-x}Sr{sub x}CuO{sub 4+{delta}} (x {le} 0.15, {delta} {le} 0.12)  

SciTech Connect

The magnetic and structural phase diagrams of the La{sub 2}CuO{sub 4+{delta}} system and the La{sub 2-x}Sr{sub x}CuO{sub 4+{delta}} are reviewed, with emphasis on recent results obtained from magnetic and structural neutron diffraction, thermogravimetric analysis, iodometric titration, magnetic susceptibility {chi}(T), and {sup 129}La nuclear quadrupole resonance (NQR) measurements.

Johnston, D.C.; Borsa, F.; Canfield, P.C. [Iowa State Univ. of Science and Technology, Ames, IA (United States)] [and others

1993-10-31

349

Nuclear spin-lattice relaxation times of metallic antimony at low temperatures  

Microsoft Academic Search

We have used pulsed Nuclear Quadrupole Resonance (NQR) techniques to measure the nuclear spin-lattice relaxation times in antimony at low temperatures. High quality echoes with strong signal\\/noise ratios were only observed for finely powdered samples of high purity (99.9999%). The samples were carefully annealed and diluted with fine silica to below the percolation limit to minimize RF heating. The powder

E. B. Genio; J. Xu; T. Lang; G. G. Ihas; N. S. Sullivan

1995-01-01

350

Etude par resonance quadripolaire des noyaux 63-Cu et 75-As de complexes tetrameres de la triethylarsine avec des halogenures de cuivre(I)  

NASA Astrophysics Data System (ADS)

63-Cu and 75-As quadrupole resonance results have been obtained for the tetrameric triethylarsine copper(I) halides (Cl, Br and I). Unusual behaviours of the temperature dependence of the 63-Cu and 75-As quadrupole resonance lines have been observed simultaneously. Between 77 and 300 K, the chlorine derivative undergoes two structural phase changes at 93 and 173 K, while phase transformations occur at 152 and 86 K respectively for the bromine and iodine derivatives.

Ribas, J.; Durand, M.; Jugie, G.

1983-12-01

351

Crossing a coupling spin resonance with an RF dipole  

NASA Astrophysics Data System (ADS)

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.

2001-06-01

352

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

353

Zeeman perturbed nuclear quadrupole spin echo envelope modulations for spin 3/2 nuclei in polycrystalline specimens  

NASA Astrophysics Data System (ADS)

The results of theoretical and experimental studies of Zeeman-perturbed nuclear quadrupole spin echo envelope modulations (ZSEEM) for spin 3/2 nuclei in polycrystalline specimens are presented. The response of the Zeeman-perturbed spin ensemble to resonant two pulse excitations has been calculated using the density matrix formalism. The theoretical calculation assumes a parallel orientation of the external r.f. and static Zeeman fields and an arbitrary orientation of these fields to the principal axes system of the electric field gradient. A numerical powder averaging procedure has been adopted to simulate the response of the polycrystalline specimens. Using a coherent pulsed nuclear quadrupole resonance spectrometer the ZSEEM patterns of the 35Cl nuclei have been recorded in polycrystalline specimens of potassium chlorate, barium chlorate, mercuric chloride (two sites) and antimony trichloride (two sites) using the ?/2-?-?/2 sequence. The theoretical and experimental ZSEEM patterns have been compared. In the case of mercuric chloride, the experimental 35Cl ZSEEM patterns are found to be nearly identical for the two sites and correspond to a near-zero value of the asymmetry parameter, ?, of the electric field gradient tensor. The difference in the ? values for the two 35Cl sites (? 006 and ?016) in antimony trichloride is clearly reflected in the experimental and theoretical ZSEEM patterns. The present study indicates the feasibility of evaluating ? for spin 3/2 nuclei in polycrystalline specimens from ZSEEM investigations.

Ramachandran, R.; Narasimhan, P. T.

354

A detailed account of the correction of parasitic sextupole fields in a magnetic quadrupole lens  

NASA Astrophysics Data System (ADS)

Most nuclear microprobes for focusing MeV light ion beams use quadrupole lenses as the final demagnifying element. However the spatial resolution attainable in most microprobes is limited by parasitic sextupole fields in the quadrupole lenses. These sextupole fields can be corrected by imbalancing the currents flowing through the pole piece coils of magnetic quadrupoles, or making the pole piece voltages of electrostatic quadrupoles asymmetric. This paper describes in detail the procedure for correcting the parasitic sextupole field present in a magnetic quadrupole lens using the shadow image method.

Breese, M. B. H.; Jamieson, D. N.

1993-11-01

355

Development and beam test of a continuous wave radio frequency quadrupole accelerator  

NASA Astrophysics Data System (ADS)

The front end of any modern ion accelerator includes a radio frequency quadrupole (RFQ). While many pulsed ion linacs successfully operate RFQs, several ion accelerators worldwide have significant difficulties operating continuous wave (CW) RFQs to design specifications. In this paper we describe the development and results of the beam commissioning of a CW RFQ designed and built for the National User Facility: Argonne Tandem Linac Accelerator System (ATLAS). Several innovative ideas were implemented in this CW RFQ. By selecting a multisegment split-coaxial structure, we reached moderate transverse dimensions for a 60.625-MHz resonator and provided a highly stabilized electromagnetic field distribution. The accelerating section of the RFQ occupies approximately 50% of the total length and is based on a trapezoidal vane tip modulation that increased the resonator shunt impedance by 60% in this section as compared to conventional sinusoidal modulation. To form an axially symmetric beam exiting the RFQ, a very short output radial matcher with a length of 0.75?? was developed. The RFQ is designed as a 100% oxygen-free electronic (OFE) copper structure and fabricated with a two-step furnace brazing process. The radio frequency (rf) measurements show excellent rf properties for the resonator, with a measured intrinsic Q equal to 94% of the simulated value for OFE copper. An O5+ ion beam extracted from an electron cyclotron resonance ion source was used for the RFQ commissioning. In off-line beam testing, we found excellent coincidence of the measured beam parameters with the results of beam dynamics simulations performed using the beam dynamics code TRACK, which was developed at Argonne. These results demonstrate the great success of the RFQ design and fabrication technology developed here, which can be applied to future CW RFQs.

Ostroumov, P. N.; Mustapha, B.; Barcikowski, A.; Dickerson, C.; Kolomiets, A. A.; Kondrashev, S. A.; Luo, Y.; Paskvan, D.; Perry, A.; Schrage, D.; Sharamentov, S. I.; Sommer, R.; Toter, W.; Zinkann, G.

2012-11-01

356

Resonant positronium formation in atomic gases  

NASA Astrophysics Data System (ADS)

A method is presented for calculation of quasistationary excited states of positronium ions. These states are treated as bound positron states in the quadrupole field of an excited valence electron, which are capable of decaying both with positron emission into the continuous spectrum, and with positronium emission. The existence of such states should manifest itself in resonances in the positronium formation section upon motion of positrons with energy in the eV range. The resonant section parameters are calculated for a number of atoms.

Bukhman, N. S.; Zon, B. A.

1984-03-01

357

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

358

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

359

Borman effect in resonant diffraction of X-rays  

SciTech Connect

A dynamic theory of resonant diffraction (occurring when the energy of incident radiation is close to the energy of the absorption edge of an element in the composition of a given substance) of synchronous X-rays is developed in the two-wave approximation in the coplanar Laue geometry for large grazing angles in perfect crystals. A sharp decrease in the absorption coefficient in the substance with simultaneously satisfied diffraction conditions (Borman effect) is demonstrated, and the theoretical and first experimental results are compared. The calculations reveal the possibility of applying this approach in analyzing the quadrupole-quadrupole contribution to the absorption coefficient.

Oreshko, A. P., E-mail: ap.oreshko@physics.msu.ru [Moscow State University (Russian Federation)

2013-08-15

360

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

361

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

362

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

363

The development of compact magnetic quadrupoles for ILSE  

SciTech Connect

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

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

1990-08-01

364

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

365

Superferric quadrupoles for FAIR Super FRS energy buncher  

NASA Astrophysics Data System (ADS)

The quadrupole magnets for FAIR Super FRS energy buncher have large usable aperture, high magnetic pole-tip field and high gradient field quality. The iron-dominated magnets with superconducting coils have to be used in this application. The NbTi coil, laminated iron, and support structure of about 22 tons is immersed in liquid helium. The 4.5 K helium chamber is completely covered with a thermal shield cooled by helium at 50-80 K on its outer and inner surface. The helium chamber and thermal shield is enclosed in a vacuum shell. The paper presents design details of the long quadrupole. Coupled thermal, magnetic and structural analysis was carried out to design the magnet iron, magnet coil, helium vessel and support links and ensure the required gradient field quality is achieved. The paper also presents the design of support links and outer vacuum chamber.

Pal, G.; Bhunia, U.; Akhter, J.; Nandi, C.; Datta, A.; Sarma, P. R.; Roy, S.; Bajirao, S.; Bhattacharyya, S.; Bhattacharyya, T. K.; Dey, M. K.; Mallik, C.; Bhandari, R. K.

2012-12-01

366

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

367

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

368

Measurement reports for the cryogenically-cooled drift tube quadrupoles  

SciTech Connect

This compilation contains quadrupole measurement reports for LANL type A and type E drift tube cryoquads. The cryoquad information gives s/n, vendor, field strength, phase, b3/b2, b4/b2, b5/b2, b6/b2, center wire location. The measurements for the harmonic measuring system gives time and date of measurements, magnet p/n, coil p/n, coil radii, coil turns, low and high gain, and temperature. Quadrupole information includes effective B` X L, and magnetic center. Bucked and unbucked calculations give signal in {mu}V{center_dot}sec, field in Tesla{center_dot}meter, B(n)/B(2), absolute and relative phase.

NONE

1993-12-31

369

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

370

Homotopy analysis method to study a quadrupole mass filter.  

PubMed

The homotopy analysis method (HAM) is applied to study the behavior of a hyperbolic rods of quadrupole mass filter and a sinusoidal potential form V(ac) ?cos(?t). Numerical computation method of a 20th-order HAM is employed to compare the physical properties of the confined ions with fifth-order Runge-Kutta method. Also, comparison is made for the first stability region, the ion trajectories in real time, the polar plots, and the ion trajectory in x?-?y plan. The results show that the two methods are fairly similar; therefore, the HAM method has potential application to solve linear and nonlinear equations of the charge particle confinement in quadrupole field. PMID:22689625

Seddighi Chaharborj, S; Seddighi Chahrborj, S; Sadat Kiai, S M; Abu Bakar, M R; Ziaeian, I; Gheisari, Y

2012-04-01

371

Quadrupole Rotation-Vibration Spectrum of the Hydrogen Molecule  

Microsoft Academic Search

IT is usually considered that molecular hydrogen does not have an infra-red rotation-vibration spectrum. However, such a spectrum may be expected as a forbidden transition made possible by the change of quadrupole moment during the vibration1. The predicted intensity of this spectrum is so low that a path of the order of 10 km. at atmospheric pressure is required to

G. Herzberg

1949-01-01

372

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

373

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

374

Radio-frequency quadrupole vane-tip geometries  

Microsoft Academic Search

Radio-frequency quadrupole (RFQ) linacs are becoming widely accepted in the accelerator community. They have the remarkable capability of simultaneously bunching low-energy ion beams and accelerating them to energies at which conventional accelerators can be used, accomplishing this with high-transmission efficiencies and low-emittance growths. The electric fields, used for radial focusing, bunching, and accelerating, are determined by the geometry of the

K. R. Crandall; R. S. Mills; T. P. Wangler

1983-01-01

375

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

376

The development of compact magnetic quadrupoles for ILSE  

Microsoft Academic Search

Magnetic focussing is selected for the 4 MeV to 10 MeV section of the Induction Linac Systems Experiments (ILSE) to study the transport of magnetically focussed spacecharge-dominated beams and to explore the engineering problems in accurate positioning of the magnetic fields in an array of quadrupoles. A prototype development program for such magnets is currently under way. A compact design

A. Faltens; S. Mukherjee; V. Brady

1990-01-01

377

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

378

Hybrid permanent magnet quadrupoles for the Recycler Ring at Fermilab  

Microsoft Academic Search

Hybrid Permanent Magnet Quadrupoles are used in several applications for the Fermilab Recycler Ring and associated beam transfer lines. Most of these magnets use a 0.6096 m long iron shell and provide integrated gradients up to 1.4 T-m\\/m with an iron pole tip radius of 41.6 mm. A 58.4 mm pole radius design is also required. Bricks of 25. 4

B. C. Brown; S. M. Pruss; G. W. Foster; H. D. Glass; D. J. Harding; G. R. Jackson; M. R. May; T. H. Nicol; J.-F. Ostiguy; R. Schlabach; J. T. Volk

1997-01-01

379

Effects of electrode geometry on quadrupole ion trap performance  

Microsoft Academic Search

Enhancement in the performance and applicability of quadrupole ion trap mass spectrometers is sought through variation of the physical structure of the device. Improvements in mass measurement accuracy are pursued through the study of chemical mass shifts, i.e. large, compound-dependent inaccuracies known to occur in traps with non-optimized geometry and believed to be related to ion structure. Experiments and simulations

James Mitchell Wells

2000-01-01

380

Test results of LHC interaction regions quadrupoles produced by Fermilab  

Microsoft Academic Search

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

S. Feher; R. Bossert; J. Carson; D. R. Chichili; J. Kerby; M. J. Lamm; A. Nobrega; T. Nicol; T. Ogitsu; D. Orris; T. Peterson; R. Rabehl; W. Robotham; R. Scanlan; P. Schlabach; C. Sylvester; J. Strait; M. Tartaglia; J. C. Tompkins; G. Velev; S. Yadav; A. V. Zlobin

2005-01-01

381

Nb3Sn quadrupole magnets for the LHC IR  

Microsoft Academic Search

The development of insertion quadrupoles with 205 T\\/m gradient and 90 mm bore represents a promising strategy to achieve the ultimate luminosity goal of 2.5 1034 cm-2s-1 at the Large Hadron Collider (LHC). At present, Nb3Sn is the only practical conductor which can meet these requirements. Since Nb3Sn is brittle, and considerably more strain sensitive than NbTi, the design

G. Sabbi; S. Caspi; L. Chiesa; M. Coccoli; D. R. Dietderich; P. Ferracin; S. A. Gourlay; R. R. Hafalia; A. F. Lietzke; A. D. McInturff; R. M. Scanlan

2003-01-01

382

On the manifestation of electron-nuclear dynamics in 59Co NQR spectra for the series of ?-cyclopentadienyl-?-(3)-1,2-dicarbollylcobalt derivatives  

NASA Astrophysics Data System (ADS)

The dependence between quadrupole coupling constants and 59Co asymmetry parameters at 77 K was established in the series (?-C5H4X)Co[?-(3)-1,2-B9H8(8-Z)C2HY]. It was shown that a region of the dynamic Opic-Pryce effect can be determined for these compounds.

Semin, G. K.; Bryukhova, E. V.

2010-02-01

383

Bonding and molecular motions in the 1:1 molecular complexes of 1,4-diazabicyclo[2.2.2]octane with tetrahalomethane as studied by means of NQR  

NASA Astrophysics Data System (ADS)

NQR spectra were observed in the complexes of 1,4-diazabicyclo[2.2.2]octane (DABCO) with tetrachloromethane and tetrabromomethane at various temperatures. A phase transition was found at 319 K for DABCOCBr 4. From spin-lattice relaxation times of nitrogen-14 in DABCOCBr 4, the activation energy of the reorientation of DABCO about the N?N axis was calculated to be 18.3 kJ/mol which agrees with the value obtained from the second moment of proton NMR spectra. The bond nature is discussed using the Townes-Dailey treatment.

Okuda, T.; Suzuki, T.; Negita, H.

1983-12-01

384

Quadrupole Magnetic Sorting of Porcine Islets of Langerhans  

PubMed Central

Islet transplantation is emerging as a treatment option for selected patients with type 1 diabetes. Inconsistent isolation, purification, and recovery of large numbers of high-quality islets remain substantial impediments to progress in the field. Removing islets as soon as they are liberated from the pancreas during digestion and circumventing the need for density gradient purification is likely to result in substantially increased viable islet yields by minimizing exposure to proteolytic enzymes, reactive oxygen intermediates, and mechanical stress associated with centrifugation. This study capitalized on the hypervascularity of islets compared with acinar tissue to explore their preferential enrichment with magnetic beads to enable immediate separation in a magnetic field utilizing a quadrupole magnetic sorting. The results demonstrate that (1) preferential enrichment of porcine islets is achievable, but homogeneous bead distribution within the pancreas is difficult to achieve with current protocols; (2) greater than 70% of islets in the dissociated pancreatic tissue were recovered by quadrupole magnetic sorting, but their purity was low; and (3) infused islets purified by density gradients and subsequently passed through quadrupole magnetic sorting had similar potency as uninfused islets. These results demonstrate proof of concept and define the steps for implementation of this technology in pig and human islet isolation.

Shenkman, Rustin M.; Chalmers, Jeffrey J.; Hering, Bernhard J.; Kirchhof, Nicole

2009-01-01

385

The exact calculation of quadrupole sources for some incompressible flows  

NASA Technical Reports Server (NTRS)

This paper is concerned with the application of the acoustic analogy of Lighthill to the acoustic and aerodynamic problems associated with moving bodies. The Ffowcs Williams-Hawkings equation, which is an interpretation of the acoustic analogy for sound generation by moving bodies, manipulates the source terms into surface and volume sources. Quite often in practice the volume sources, or quadrupoles, are neglected for various reasons. Recently, Farassat, Long and others have attempted to use the FW-H equation with the quadrupole source and neglected to solve for the surface pressure on the body. The purpose of this paper is to examine the contribution of the quadrupole source to the acoustic pressure and body surface pressure for some problems for which the exact solution is known. The inviscid, incompressible, 2-D flow, calculated using the velocity potential, is used to calculate the individual contributions of the various surface and volume source terms in the FW-H equation. The relative importance of each of the sources is then assessed.

Brentner, Kenneth S.

1988-01-01

386

Quadrupole Susceptibility of Gd-Based Filled Skutterudite Compounds  

NASA Astrophysics Data System (ADS)

It is shown that quadrupole susceptibility can be detected in Gd compounds, contrary to our textbook knowledge that a Gd3+ ion induces a pure spin moment owing to Hund's rules in an LS coupling scheme. The ground-state multiplet of Gd3+ is always characterized by J=7/2, where J denotes the total angular momentum, but in a j--j coupling scheme, one f electron in a j=7/2 octet carries a quadrupole moment, while the other six electrons fully occupy a j=5/2 sextet, where j denotes the one-electron total angular momentum. For realistic values of Coulomb interaction and spin--orbit coupling, the ground-state wavefunction is found to contain a significant amount of the j--j coupling component. By the evaluation of quadrupole susceptibility in a simple mean-field approximation, we point out the possibility of detecting the softening of an elastic constant in Gd-based filled skutterudites.

Niikura, Fumiaki; Hotta, Takashi

2012-11-01

387

Nuclear electric hexadecapole coupling constant in antimony trichloride  

NASA Astrophysics Data System (ADS)

The electric hexadecapole coupling constant of 123Sb (nuclear spin I = {1}/{2}) in SbCl 3 was determined from the accurate measurement of three nuclear quadrupole resonance frequencies, ? 1 ( {1}/{2}- {1}/{2}), ? 2 ( {3}/{2}- {5}/{2}), ? 3 ( {5}/{2}- {7}/{2}) at the same sample temperature. To avoid error produced from the change of the sample temperature, ?1, and ?2, or ?2 and ?3 were alternately and repeatedly measured as quickly as possible, and the relations between them were determined. To measure the NQR frequency quickly without the disturbance by a marker signal, two marker signals were displayed on both sides of the NQR signal. A method to evaluate the real NQR frequency from a slightly asymmetric lineshape was introduced. As a result, three NQR frequencies were determined at each sample temperature. The values of the hexadecapole coupling constant eMm, quadrupole coupling constant eQq, and asymmetry parameter ?, were found as follows; when ?2 = 67.732 MHz, eMm = 109.8 60.6 kHz, eQq = 480.5177 MHz, and ? = 0.1593909.

Gotou, Hiroshi

388

First principles Investigation of electronic Structure and ^47,49Ti and ^17O nuclear Quadrupole Interactions in the Rutile and Anatase Phases of TiO_2.  

NASA Astrophysics Data System (ADS)

The electronic structures and ^47,49Ti and ^17O nuclear quadrupole interactions in the Rutile and Anatase phases of TiO2 have been investigated using the First Principles Hartree-Fock Cluster procedure. The calculated nuclear quadrupole interaction parameters for both ^47,49Ti and ^17O are in reasonable agreement with experiment[1], especially the sign of the coupling constant e^2qQ for ^17O . Predictions are also made for e^2qQ and the asymmetry parameters in the Anatase phase, the latter being zero for ^47,49Ti as expected from crystal symmetry in this system. *Supported by NSF Division of International Programs, US-Nepal Collaboration. [1] C. Gabathuler et al "Magnetic Resonance and Related Phenomena" ed. V. Hovi, North Holland (1973); O. Kanert and H. Kolem, J. Phys. C21, 3909(1988)

Byahut, S. P.; Srinivas, Sudha; Chow, L.; Jeong, Junho; Scheicher, R. H.; Gaire, C.; Das, T. P.

2004-03-01

389

Evaluation of Molecular Quadrupole Moments from Broadening of Microwave Spectral Lines. II. Calculation of the Quadrupole Moments and Discussion  

Microsoft Academic Search

Molecular quadrupole moments of OCS, CHF3, N2O, NO, H2, HD, D2, N2, and CO2 have been obtained from the fit of the calculated line-broadening constants ?aa for self-broadening and ?ab for foreign-gas broadening to the experimental results reported in a previous paper. The theoretical line-broadening constants were calculated using Anderson's theory on pressure broadening in the modification of Tsao and

B. Th. Berendts; A. Dymanus

1968-01-01

390

Excitation and photon decay of giant resonances excited by intermediate 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 giant resonances. In particular, recent measurements have been made 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. 22 refs., 19 figs., 1 tab.

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

1987-01-01

391

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

392

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

PubMed

The quinolinol derivatives clioquinol (5-chloro-7-iodo-8-quinolinol, Quinoform) and cloxiquine (5-chloro-8-quinolinol) were studied experimentally in the solid state via ?Cl NQR, H-?O and H-?N NQDR spectroscopies, and theoretically by density functional theory (DFT). The supramolecular synthon pattern of O-HN hydrogen bonds linking dimers and ?-? stacking interactions were described within the QTAIM (quantum theory of atoms in molecules) /DFT (density functional theory) formalism. Both proton donor and acceptor sites in O-HN bonds were characterized using H-?O and H-?N NQDR spectroscopies and QTAIM. The possibility of the existence of O-HH-O dihydrogen bonds was excluded. The weak intermolecular interactions in the crystals of clioquinol and cloxiquine were detected and examined. The results obtained in this work suggest that considerable differences in the NQR parameters for the planar and twisted supramolecular synthons permit differentiation between specific polymorphic forms, and indicate that the more planar supramolecular synthons are accompanied by a greater number of weaker hydrogen bonds linking them and stronger ?? stacking interactions. PMID:21080020

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

2011-07-01

393

Parametric-Resonance Ionization Cooling in Twin-Helix.  

SciTech Connect

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 and cooling with stochastic effects off using GEANT4/G4beamline. We illustrate compensation of spherical aberrations and benchmark COSY Infinity, a powerful tool for aberration analysis and compensation.

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

2011-09-01

394

A new high-gradient correction quadrupole for the Fermilab luminosity upgrade  

Microsoft Academic Search

Special superconducting correction quadrupoles are needed for the luminosity upgrade of the Fermilab Tevatron Collider. These correctors are part of the low-beta system for the interaction regions at B0 and D0. The requirements are high gradient and low current. A quadrupole has been designed that meets the operating gradient of 0.63 T\\/cm at 1086 A. The one-layer quadrupole is wound

P. Mantsch; J. Carson; A. Riddiford; M. J. Lamm

1989-01-01

395

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

396

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

SciTech Connect

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

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

2004-11-01

397

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

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

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

400

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

401

Microwave spectrum, structure and electric quadrupole coupling constants of HOCl  

Microsoft Academic Search

The rotational ``a'' type spectra of H16O35Cl, H16O37Cl, D16O35Cl, D16O37Cl and D18O35Cl have been measured. The rotational constants B and C and the quadrupole coupling constants chiaa and chibb were obtained for each isotopic species. The values of DJ and DJK for H16O35Cl were also determined from centrifugal distortion analysis of the spectrum. The following values of the structural parameters

A. M. Mirri; F. Scappini; G. Cazzoli

1971-01-01

402

Test of eight superconducting arc quadrupoles for RHIC  

NASA Astrophysics Data System (ADS)

Test results from a group of eight superconducting quadrupoles made 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.; Garber, M.; Ghosh, A.; Greene, A.; Gupta, R.; Jain, A.; Kahn, S.; Kelly, E.

1994-07-01

403

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

404

Microwave Spectrum, Nuclear Quadrupole Coupling Constants, and Structure of Bromodifluoromethane  

Microsoft Academic Search

The microwave spectrum of bromodifluoromethane, CHBrF2(Halon 1201) has been studied for the first time from 7 to 40 GHz. A least-squares analysis of the observedc-type transition frequencies gave rotational and centrifugal distortion constants and components of the bromine nuclear quadrupole coupling constant tensor in the principal axes system as follows:A= 10199.7186(62) MHz,B= 2903.4150(26) MHz,C= 2360.1521(23) MHz, ?J= 0.660(14) kHz, ?JK=

Teruhiko Ogata; Susumu Kuwano; Sumio Oe

1997-01-01

405

Measurement of coupling resonance driving terms with the AC dipole  

SciTech Connect

Resonance driving terms for linear coupled betatron motion in a synchrotron ring can be determined from corresponding spectral lines of an excited coherent beam motion. An AC dipole is one of instruments to excite such a motion. When a coherent motion is excited with an AC dipole, measured Courant-Snyder parameters and betatron phase advance have apparent modulations, as if there is an additional quadrupole field at the location of the AC dipole. Hence, measurements of these parameters using the AC dipole require a proper interpretation of observed quantities. The situation is similar in measurements of resonance driving terms using the AC dipole. In this note, we derive an expression of coupled betatron motion excited with two AC dipoles in presence of skew quadrupole fields, discuss an impact of this quadrupole like effect of the AC dipole on a measurement of coupling resonance driving terms, and present an analytical method to determine the coupling resonance driving terms from quantities observed using the AC dipole.

Miyamoto, R.

2010-10-01

406

The coupling effects of hexapole and octopole fields in quadrupole ion traps: a theoretical study.  

PubMed

A theoretical method, the harmonic balance method, was introduced to study the coupling effects of hexapole and octopole fields on ion motion in a quadrupole ion trap. Ion motion characteristics, such as ion motion center displacement, ion secular frequency shift, nonlinear resonance curve and buffer gas damping effects, have been studied with the presence of both hexapole and octopole fields. It is found that hexapole fields have bigger impacts on ion motion center displacement, while octopole fields dominate ion secular frequency shift. Furthermore, the nonlinear features originated from hexapole and octopole fields could enhance or cancel each other, which provide us more space in a practical ion trap design process. As an example, an ion trap with improved performance was designed using a specific combination of hexapole and octopole fields. In this ion trap, a hexapole field was used to achieve efficient ion directional ejection, while an octopole field was added to correct the chemical mass shift and resolution degradation introduced by the hexapole field. PMID:23893641

Wang, Yuzhuo; Huang, Zejian; Jiang, You; Xiong, Xingchuang; Deng, Yulin; Fang, Xiang; Xu, Wei

2013-08-01

407

H/D exchange of gas phase bradykinin ions in a linear quadrupole ion trap.  

PubMed

The gas phase H/D exchange reaction of bradykinin ions, as well as fragment ions of bradykinin generated through collisions in an orifice skimmer region, have been studied with a linear quadrupole ion trap (LIT) reflectron time-of-flight (rTOF) mass spectrometer system. The reaction in the trap takes only tens of seconds at a pressure of few mTorr of D2O or CD3OD. The exchange rate and hydrogen exchange level are not sensitive to the trapping q value over a broad range, provided q is not close to the stability boundary (q = 0.908). The relative rates and hydrogen exchange levels of protonated and sodiated +1 and +2 ions are similar to those observed previously by others with a Fourier transform ion cyclotron resonance (FTICR) mass spectrometer system. The doubly and triply protonated ions show multimodal isotopic distributions, suggesting the presence of several different conformations. The y fragment ions show greater exchange rates and levels than a or b ions, and when water or ammonia is lost from the fragment ions, no exchange is observed. PMID:12586457

Mao, Dunmin; Douglas, D J

2003-02-01

408

Powder MAS NMR lineshapes of quadrupolar nuclei in the presence of second-order quadrupole interaction.  

PubMed

We derive a complete analytical solution for the powder magic angle spinning (MAS) nuclear magnetic resonance (NMR) lineshape in the presence of second-order quadrupole interaction, considering a radiofrequency (rf) pulse of finite width, a finite MAS frequency, and a non-zero asymmetry parameter. (Ix) is calculated using two approaches. The first applies time-dependent perturbation theory in the presence of the rf pulse and stationary perturbation theory (SPT) in its absence. The second is based on the Magnus expansion of the density matrix in the interaction representation during the pulse and SPT in its absence. We solve the problem in the laboratory frame using the properties of the Fourier transform and spin operators. Diagonalisation is not required. Both approaches agree well with each other under all conditions and also with the transition probability approach for the central transition. The Magnus expansion exists at all times and the effect of the non-secular terms is negligible. We describe an analytical method of averaging (Ix) over the Euler angles and simulate the 11B MAS NMR lineshapes for crystalline and vitreous B2O3. A critical analysis is given of all earlier calculations of the MAS NMR lineshape. PMID:10928635

Ajoy, G; Ramakrishna, J; Baheli, S; Klinowski, J

2000-07-01

409

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

NASA Astrophysics Data System (ADS)

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.

2011-09-01

410

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

411

High Reliability Prototype Quadrupole for the Next Linear Collider  

NASA Astrophysics Data System (ADS)

The Next Linear Collider (NLC) will require over 5600 magnets, each of which must be highly reliable and/or quickly repairable in order that the NLC reach its 85/ overall availability goal. A multidiscipline engineering team was assembled at SLAC to develop a more reliable electromagnet design than historically had been achieved at SLAC. This team carried out a Failure Mode and Effects Analysis (FMEA) on a standard SLAC quadrupole magnet system. They overcame a number of longstanding design prejudices, producing 10 major design changes. This paper describes how a prototype magnet was constructed and the extensive testing carried out on it to prove full functionality with an improvement in reliability. The magnet's fabrication cost will be compared to the cost of a magnet with the same requirements made in the historic SLAC way. The NLC will use over 1600 of these 12.7 mm bore quadrupoles with a range of integrated strengths from 0.6 to 132 Tesla, a maximum gradient of 135 Tesla per meter, an adjustment range of 0 to -20/ and core lengths from 324 mm to 972 mm. The magnetic center must remain stable to within 1 micron during the 20/ adjustment. A magnetic measurement set-up has been developed that can measure sub-micron shifts of a magnetic center. The prototype satisfied the center shift requirement over the full range of integrated strengths.

Spencer, C. M.

2001-01-01

412

High Reliability Prototype Quadrupole for the Next Linear Collider  

SciTech Connect

The Next Linear Collider (NLC) will require over 5600 magnets, each of which must be highly reliable and/or quickly repairable in order that the NLC reach its 85% overall availability goal. A multidiscipline engineering team was assembled at SLAC to develop a more reliable electromagnet design than historically had been achieved at SLAC. This team carried out a Failure Mode and Effects Analysis (FMEA) on a standard SLAC quadrupole magnet system. They overcame a number of longstanding design prejudices, producing 10 major design changes. This paper describes how a prototype magnet was constructed and the extensive testing carried out on it to prove full functionality with an improvement in reliability. The magnet's fabrication cost will be compared to the cost of a magnet with the same requirements made in the historic SLAC way. The NLC will use over 1600 of these 12.7 mm bore quadrupoles with a range of integrated strengths from 0.6 to 132 Tesla, a maximum gradient of 135 Tesla per meter, an adjustment range of 0 to -20% and core lengths from 324 mm to 972 mm. The magnetic center must remain stable to within 1 micron during the 20% adjustment. A magnetic measurement set-up has been developed that can measure sub-micron shifts of a magnetic center. The prototype satisfied the center shift requirement over the full range of integrated strengths.

Spencer, Cherrill M

2001-01-04

413

VIBRATION MEASUREMENTS IN A RHIC QUADRUPOLE AT CRYOGENIC TEMPERATURES.  

SciTech Connect

One of the concerns in using compact superconducting magnets in the final focus region of the ILC is the influence of the cryogen flow on the vibration characteristics. As a first step towards characterizing such motion at nanometer levels, a project was undertaken at BNL to measure the vibrations in a spare RHIC quadrupole under cryogenic conditions. Given the constraints of cryogenic operation, and limited space available, it was decided to use a dual head laser Doppler vibrometer for this work. The performance of the laser vibrometer was tested in a series of room temperature tests and compared with results from Mark L4 geophones. The laser system was then used to measure the vibration of the cold mass of the quadrupole with respect to the outside warm enclosure. These measurements were carried out both with and without the flow of cold helium through the magnet. The results indicate only a minor increase in motion in the horizontal direction (where the cold mass is relatively free to move).

JAIN, A.; AYDIN, S.; HE, P.; ANERELLA, M.; GANETIS, G.; HARRISON, M.; PARKER, B.; PLATE, S.

2005-10-17

414

Extracting the ?- electric quadrupole moment from lattice QCD data  

NASA Astrophysics Data System (ADS)

The ?- has an extremely long lifetime, and is the most stable of the baryons with spin 3/2. Therefore the ?- 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 ?- 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?-=GE2(0)(e)/(2M?), involves an extrapolation of the numerical lattice results. In this work, we reproduce the lattice QCD data with a covariant spectator quark model for ?- 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?-. Our prediction is Q?-=(0.960.02)10-2efm2 [GE2(0)=0.6800.012].

Ramalho, G.; Pea, M. T.

2011-03-01

415

A new method for distinguishing between Al 2X 6 (X=Cl, Br) conformers based on ab initio calculated nuclear quadrupole coupling constants  

NASA Astrophysics Data System (ADS)

Nuclear quadrupole coupling constants ( ?) of 27Al, 35Cl and 81Br in AlX 3 monomers as well as Al 2X 6 (X=Cl, Br) dimers are calculated at the RHF/6-311G* and B 3LYP/6-311G* levels, using G AUSSIAN 98 package. Correlations are made between ? and dihedral angles ?, of Al 2X 6. These ?s are produced through the ring puckering motions about the hinge line which joins the two bridge halogens (X b). Nuclear quadrupole coupling constants of 35Cl, 81Br and 27Al are used as probes for monitoring the departure of the symmetry of Al 2X 6 from a high symmetry point group D 2h to a lower one. The ?s of chlorine nuclei of AlCl 3 differ significantly from those of Al 2Cl 6. These differences appear negligible for AlBr 3 in comparison to Al 2Br 6. This work demonstrates the considerable sensitivity of nuclear quadrupole resonance in distinguishing between Al 2X 6 conformers. This is in comparison to the usage of energy differences which is customarily employed.

Hadipour, N. L.; Elmi, F.

2003-03-01

416

Nuclear quadrupole moments from molecular microwave data: The quadrupole moment of 85Rb and 87Rb nuclei and survey of molecular data for alkali-metal nuclei  

NASA Astrophysics Data System (ADS)

The ``molecular'' values of the quadrupole moment of the Rb and Na nuclei have been obtained by using spectroscopic values of nuclear coupling constants and high-level-correlated relativistic calculations of the electric-field gradients in fluorides and chlorides. The recommended value for the 85Rb nucleus which follows from the present study is about 276 mb, with expected error bars of the order of about 1 mb. This value agrees with the atomic spectroscopy data, and suggests that the quadrupole coupling constant measured for the RbCl molecule is in error. The present calculations for 23Na confirm the earlier molecular result for its electric quadrupole moment, and combined with recent atomic calculations lead to the recommended value in the range 104-105 mb. The molecular results for nuclear quadrupole moments of the alkali-metal nuclei are reviewed leading to a list of the corresponding recommended values.

Kell, Vladimir; Sadlej, Andrzej J.

1999-11-01

417

Electron penetration into the nucleus and its effect on the quadrupole interaction  

SciTech Connect

A series expansion of the interaction between a nucleus and its surrounding electron distribution provides terms that are well-known in the study of hyperfine interactions: the familiar quadrupole interaction and the less familiar hexadecapole interaction. If the penetration of electrons into the nucleus is taken into account, various corrections to these multipole interactions appear. The best known correction is a scalar term related to the isotope shift and the isomer shift. This paper discusses a related tensor correction, which modifies the quadrupole interaction if electrons penetrate the nucleus: the quadrupole shift. We describe the mathematical formalism and provide first-principles calculations of the quadrupole shift for a large set of solids. Fully relativistic calculations that explicitly take a finite nucleus into account turn out to be mandatory. Our analysis shows that the quadrupole shift becomes appreciably large for heavy elements. Implications for experimental high-precision studies of quadrupole interactions and quadrupole moment ratios are discussed. A literature review of other small quadrupole-like effects is presented as well (pseudoquadrupole effect, isotopologue anomaly, etc.).

Koch, Katrin; Rosner, Helge [Max Planck Institute for Chemical Physics of Solids, Noethnitzer Str. 40, DE-01187 Dresden (Germany); Koepernik, Klaus [IFW Dresden, Institute for Solid State Research, P. O. Box 270116, DE-01171 Dresden (Germany); Neck, Dimitri Van [Center for Molecular Modeling, Ghent University, Technologiepark 903, BE-9052 Zwijnaarde (Belgium); Cottenier, Stefaan [Center for Molecular Modeling, Ghent University, Technologiepark 903, BE-9052 Zwijnaarde (Belgium); Instituut voor Kern-en Stralingsfysica and INPAC, K.U.Leuven, Celestijnenlaan 200 D, BE-3001 Leuven (Belgium)

2010-03-15

418

Magnetic design of superconducting quadrupoles for a SC linac for APT  

Microsoft Academic Search

This paper describes the magnetic design for superconducting quadrupoles to be used in the superconducting option of the proton linac for the Accelerator Production of Tritium (APT) project. The quadrupole magnets provide the focusing for a singlet FODO lattice used in the linac. The magnets have a 16 cm (13 cm) aperture in the hi-? (medium-?) section of the linac.

S. Kahn; P. Wanderer

1997-01-01

419

The effect and correction of coupling generated by the RHIC triplet quadrupoles  

Microsoft Academic Search

This study explores the possibility of operating the nominal RHIC coupling correction system in local decoupling mode, where a subset of skew quadrupoles are independently set by minimizing the coupling as locally measured by beam position monitors. The goal is to establish a correction procedure for the skew quadrupole errors in the interaction region triplets that does not rely on

F. Pilat; S. Peggs; S. Tepikian; D. Trbojevic; J. Wei

1995-01-01

420

The effect and correction of couplings generated by the RHIC triplet quadrupoles  

Microsoft Academic Search

This study explores the possibility of operating the nominal RHIC coupling correction system in local decoupling mode, where a subset of skew quadrupoles are independently set by minimizing the coupling as locally measured by beam position monitors. The goal is to establish a correction procedure for the skew quadrupole errors in the interaction region triplets that does not rely on

F. Pilat; Stephen G. Peggs; S. Tepikian; D. Trbojevic; J. Wei

1996-01-01

421

Physical implications of the use of primitive and traceless electric quadrupole moments  

Microsoft Academic Search

Theories of certain electromagnetic effects, such as chiral phenomena in fluids and crystals and gyrotropic birefringence in antiferromagnetic crystals, require the inclusion of electric quadrupole contributions for a full description of the effect. In a number of these theories the electric quadrupole moment is defined to be traceless, as indeed is the general practice for such moments in nuclear physics.

M. J. Gunning; R. E. Raab

1997-01-01

422

High order beam features and fitting quadrupole scan data to particle code model  

Microsoft Academic Search

Quadrupole scans in the HEBT of the 6.7 MeV LEDA RFQ were analyzed to characterize the RFQ output beam. In previous work, profiles measured by the wire scanner were fit to models (beam parameterizations and HEBT simulations) to determine the transverse Courant-Snyder parameters , , and at the RFQ exit. Unfortunately, at the larger quadrupole settings, the measured profiles showed

W. P. Lysenko; R. W. Garnett; J. D. Gilpatrick; J. Qiang; L. J. Rybarcyk; Robert Ryne; J. D. Schneider; H. V. Smith; L. M. Young; M. E. Schulze

2003-01-01

423

Measurement of nuclear quadrupole interaction in iron complexes using the Mossbauer effect  

Microsoft Academic Search

Nuclear quadrupole splitting and isomer shifts were measured for iron ; complexes at room temperature. The quadrupole coupling measurements were made by ; measuring the Mossbauer effect with iron in different electronic surroundings. ; The 14 different complexes in the bivalent and trivalent state of the spin-free ; and spin-paired type were investigated as absorbers. The complexes include ; potassium

N. L. Costa; J. Danon; R. M. Xavier

1962-01-01

424

Electric Quadrupole Moments of High Spin Isomers in exp 209 Po and exp 210 Po.  

National Technical Information Service (NTIS)

High spin exp 209 , exp 210 Po isomers were recoil implanted into tetragonal tin and the electric quadrupole coupling constants have been measured with the TDPAC technique. Using a calculated value for the quadrupole moment of Q( exp 210 Po(8 exp + )) = 5...

E. Dafni M. H. Rafailovich T. Marshall G. Schatz G. D. Sprouse

1981-01-01

425

COMPARISON OF PRIORITY POLLUTANT RESPONSE FACTORS FOR TRIPLE AND SINGLE QUADRUPOLE MASS SPECTROMETERS  

EPA Science Inventory

Seventy-four percent of the electron impact GC/MS response factors (RF) determined on a triple quadrupole mass spectrometer for 53 extractable priority pollutants were found to be within + or - 15 percent of values determined in an independent interlaboratory single quadrupole GC...

426

Quench performance of Fermilab high gradient quadrupole short models for the LHC Interaction Regions  

Microsoft Academic Search

Fermilab and LBNL are in the midst of superconducting magnet R&D program to test and optimize the design of quadrupoles to be used in the LHC Interaction Region inner triplets. The magnets are required to deliver a 215 T\\/m gradient across a 70 mm aperture. Five quadrupole short models have been fabricated and four of them have been tested. This

N. Andreev; T. Arkan; R. Bossert; J. Brandt; D. Chichili; J. DiMarco; S. Feher; J. Kerby; M. J. Lamm; P. J. Limon; F. Nobrega; D. Orris; I. Novitski; J. P. Ozelis; T. Peterson; G. Sabbi; P. Schlabach; J. Strait; M. Tartaglia; J. C. Tompkins; S. Yadav; A. V. Zlobin; S. Caspi; A. D. McInturff; R. M. Scanlan; A. Ghosh

1999-01-01

427

Analysis of magnetic nanoparticles using quadrupole magnetic field-flow fractionation  

NASA Astrophysics Data System (ADS)

The new technique of quadrupole magnetic field-flow fractionation is described. It is a separation and characterization technique for particulate magnetic materials. Components of a sample are eluted from the separation channel at times dependent on the strength of their interaction with the magnetic field. A quadrupole electromagnet allows a programmed reduction of field strength during analysis of polydisperse samples.

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

2005-05-01

428

Field quality measurements of the LQXB inner triplet quadrupoles for LHC  

Microsoft Academic Search

As a part of the USLHC program, Fermilab is building half of the inner triplet quadrupole magnets for the LHC. Two identical quadrupoles (MQXB) with a dipole corrector between them in a single cryogenic unit (LQXB) comprise the Q2 optical element of the final focus triplets in the interaction regions. The 5.5 m long MQXB have a 70 mm aperture

G. V. Velev; R. Bossert; R. Carcagno; J. DiMarco; S. Feher; H. Glass; V. V. Kashikhin; J. Kerby; M. Lamm; A. Makulski; A. Nobrega; J. Nogiec; D. Orris; T. Peterson; R. Rabehl; P. Schlabach; J. Strait; C. Sylvester; M. Tartaglia; J. C. Tompkins; A. V. Zlobin

2005-01-01

429

Miniature micromachined quadrupole mass spectrometer array and method of making the same  

NASA Technical Reports Server (NTRS)

The present invention provides a quadrupole mass spectrometer and an ion filter for use in the quadrupole mass spectrometer. The ion filter includes a thin patterned layer including a two-dimensional array of poles forming one or more quadrupoles. The patterned layer design permits the use of very short poles and with a very dense spacing of the poles, so that the ion filter may be made very small. Also provided is a method for making the ion filter and the quadrupole mass spectrometer. The method involves forming the patterned layer of the ion filter in such a way that as the poles of the patterned layer are formed, they have the relative positioning and aligrnent for use in a final quadrupole mass spectrometer device.

Chutjian, Ara (Inventor); Hecht, Michael (Inventor); Orient, Otto (Inventor); Wiberg, Dean (Inventor); Brennen, Reid A. (Inventor)

2001-01-01

430

Miniature micromachined quadrupole mass spectrometer array and method of making the same  

NASA Technical Reports Server (NTRS)

The present invention provides a quadrupole mass spectrometer and an ion filter for use in the quadrupole mass spectrometer. The ion filter includes a thin patterned layer including a two-dimensional array of poles forming one or more quadrupoles. The patterned layer design permits the use of very short poles and with a very dense spacing of the poles, so that the ion filter may be made very small. Also provided is a method for making the ion filter and the quadrupole mass spectrometer. The method involves forming the patterned layer of the ion filter in such a way that as the poles of the patterned layer are formed, they have the relative positioning and alignment for use in a final quadrupole mass spectrometer device.

Chutjian, Ara (Inventor); Hecht, Michael (Inventor); Orient, Otto (Inventor); Wiberg, Dean (Inventor); Brennen, Reid A. (Inventor)

2001-01-01

431

Miniature micromachined quadrupole mass spectrometer array and method of making the same  

NASA Technical Reports Server (NTRS)

The present invention provides a quadrupole mass spectrometer and an ion filter for use in the quadrupole mass spectrometer. The ion filter includes a thin patterned layer including a two-dimensional array of poles forming one or more quadrupoles. The patterned layer design permits the use of very short poles and with a very dense spacing of the poles, so that the ion filter may be made very small. Also provided is a method for making the ion filter and the quadrupole mass spectrometer. The method involves forming the patterned layer of the ion filter in such a way that as the poles of the patterned layer are formed, they have the relative positioning and alignment for use in a final quadrupole mass spectrometer device.

Chutjian, Ara (Inventor); Hecht, Michael (Inventor); Orient, Otto (Inventor); Wiberg, Dean (Inventor); Brennen, Reid A. (Inventor)

2000-01-01

432

Hybrid quadrupole/time-of-flight mass spectrometers for analysis of biomolecules.  

PubMed

The basic principles of quadrupole/time-of-flight (TOF) mass spectrometers are discussed. These instruments can be used for ions produced either by electrospray ionization (ESI) or by matrix-assisted laser desorption ionization (MALDI). In the most common configuration, the functions of collisional cooling, parent ion selection, and collision-induced dissociation are carried out successively in three separate quadrupoles. The ions are then injected orthogonally into a TOF spectrometer, which makes the m/z measurement. Thus, these hybrid instruments benefit from the versatile ability of quadrupoles to carry out various tasks and from the high performance of TOF spectrometers in both simple mass spectrometry (MS) and tandem (MS/MS) modes. Significantly, collisions in the initial quadrupole decouple the instrument almost completely from the ion production process, so the quadrupole/TOF spectrometer is a stable device that is relatively insensitive to variations in the ion source. PMID:16401506

Ens, Werner; Standing, Kenneth G

2005-01-01

433

Physical implications of the use of primitive and traceless electric quadrupole moments  

NASA Astrophysics Data System (ADS)

Theories of certain electromagnetic effects, such as chiral phenomena in fluids and crystals and gyrotropic birefringence in antiferromagnetic crystals, require the inclusion of electric quadrupole contributions for a full description of the effect. In a number of these theories the electric quadrupole moment is defined to be traceless, as indeed is the general practice for such moments in nuclear physics. It is shown that, when the traceless quadrupole moment is used in the derivation of the wave equation that describes light propagation through an optically active uniaxial medium, this equation and properties derived from it, in particular refractive index, depend in general on the arbitrary origin used to specify the quadrupole moment. This is physically unacceptable for an observable property of a substance. By contrast, this defect does not occur if the definition of the primitive quadrupole moment is adopted, namely qr r . beta

Gunning, M. J.; Raab, R. E.

434

Miniature micromachined quadrupole mass spectrometer array and method of making the same  

NASA Technical Reports Server (NTRS)

The present invention provides a quadrupole mass spectrometer and an ion filter, or pole array, for use in the quadrupole mass spectrometer. The ion filter includes a thin patterned layer including a two-dimensional array of poles forming one or more quadrupoles. The patterned layer design permits the use of very short poles and with a very dense spacing of the poles, so that the ion filter may be made very small. Also provided is a method for making the ion filter and the quadrupole mass spectrometer. The method involves forming the patterned layer of the ion filter in such a way that as the poles of the patterned layer are formed, they have the relative positioning and alignment for use in a final quadrupole mass spectrometer device.

Chutjian, Ara (Inventor); Fuerstenau, Stephen D. (Inventor); Orient, Otto J. (Inventor); Yee, Karl Y. (Inventor); Rice, John T. (Inventor)

2002-01-01

435

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

436

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

437

Photon decay of giant resonances  

SciTech Connect

The total gamma-decay probability, the ground-state gamma branching ratio, and the branching ratios to a number of low-lying states as a function of excitation energy have been determined in /sup 208/Pb to approximately 15 MeV. The total yield of ground-state E2 gamma radiation in /sup 208/Pb can only be understood if decay of compound states is considered. Other observations in /sup 208/Pb include the absence of a significant branch from the giant quadrupole resonance (GQR) to the low-lying collective states at 2.6 MeV and 4.08 MeV, and a strong branch to a 3/sup -/ state at 4.97 MeV. 20 refs., 6 figs., 1 tab.

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

1986-01-01

438

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

439

Inelastic Scattering of exp 9 Be of 27 MeV/A to Giant Resonances.  

National Technical Information Service (NTIS)

Inelastic scattering spectra have been measured with 245 MeV incident energy exp 9 Be ions, on exp 208 Pb target. They show large excitation of the exp 208 Pb giant quadrupole resonance. DWBA calculations are reported and compared with the data. (Atominde...

D. Lebrun M. Buenerd M. Bini B. G. Harvey R. Legrain

1980-01-01

440

Isotopically selective counting of noble gas atoms, using resonance ionization spectroscopy  

Microsoft Academic Search

The technique of Resonance Ionization Spectroscopy (RIS) is being extended to develop a means for counting individual atoms of a selected isotope of a noble gas. In this method, lasers are used for RIS to obtain atomic species (Z) selectivity and a small quadrupole mass spectrometer provides isotopic (A) selectivity. A progress report on the objective of counting each atom

C. H. Chen

1984-01-01

441

Antiproton-Nucleus Interaction and Nuclear E2 Resonance Effect in Molybdenum and Neodymium Isotopes.  

National Technical Information Service (NTIS)

Antiprotonix X-radiation from /sup 92/Mo, /sup 94/Mo, /sup 95/Mo, /sup 98/Mo, /sup 100/Mo and /sup 146/Nd, /sup 148/Nd was measured with Ge detectors at the LEAR (CERN). The nuclear E2 resonance effect (configuration mixing by dynamic electric quadrupole ...

W. Kanert

1986-01-01

442