Note: This page contains sample records for the topic understanding nuclear quadrupole from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: August 15, 2014.
1

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, Régis Tadeu; Teodoro, Tiago Quevedo; Haiduke, Roberto Luiz Andrade

2014-06-21

2

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

NASA Astrophysics Data System (ADS)

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

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

3

Explosives detection by nuclear quadrupole resonance (NQR)  

NASA Astrophysics Data System (ADS)

Pure nuclear quadrupole resonance (NQR) of 14N nuclei is quite promising as a method for detecting explosives such as RDX and contraband narcotics such as cocaine and heroin in quantities of interest. Pure NQR is conducted without an external applied magnetic field, so potential concerns about damage to magnetically encoded data or exposure of personnel to large magnetic fields are not relevant. Because NQR frequencies of different compounds are quite distinct, we do not encounter false alarms from the NQR signals of other benign materials. We have constructed a laboratory prototype NQR explosives detector which interrogates a volume of 300 liters (10 ft3). This paper presents abbreviated results from a demonstration of the laboratory prototype NQR explosives detector conducted at the Federal Aviation Administration Technical Center in May 1994 on RDX-based explosives.

Garroway, Allen N.; Buess, M. L.; Yesinowski, J. P.; Miller, J. B.; Krauss, Ronald A.

1994-10-01

4

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

5

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.

6

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

7

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

8

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

9

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

10

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

11

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

12

Nuclear quadrupole interaction of199mHg-ferrocenethiol complexes  

NASA Astrophysics Data System (ADS)

We determined the199mHg nuclear quadrupole interaction (NQI) by time differential perturbed angular correlation in the following ferrocenethiol complexes with mercury: ferrocenethiol ( v Q =1253(4) MHz, ?=0); 1,1'-ferrocenedithiol (47% v Q =1555(8) MHz, ?=0.13(2); 25% v Q =726(19) MHz, ?=0.81(2); rest unspecific); 2-ferrocenyl-ethanethiol ( v Q =1306(6) MHz, ?=0.17(1)); and a 1, 1'-bis (2-mercapto-propylthio)ferrocene oligomer ( v Q =1411(5), ?=0). All NQIs are rather large with small asymmetry parameters, indicating essentially linear S-Hg-S bonds. The only exception is the minority fraction in 1,2'-ferrocenedithiol which suggests the formation of a 1,3-dithia-2-mercura[3]ferrocenophane.

Butz, T.; Tröger, W.; Pöhlmann, Th.; Nuyken, O.

1993-03-01

13

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

14

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

15

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

16

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

17

Communication: On the isotope anomaly of nuclear quadrupole coupling in molecules  

NASA Astrophysics Data System (ADS)

The dependence of the nuclear quadrupole coupling constants (NQCC) on the interaction between electrons and a nucleus of finite size is theoretically analyzed. A deviation of the ratio of the NQCCs obtained from two different isotopomers of a molecule from the ratio of the corresponding bare nuclear electric quadrupole moments, known as quadrupole anomaly, is interpreted in terms of the logarithmic derivatives of the electric field gradient at the nuclear site with respect to the nuclear charge radius. Quantum chemical calculations based on a Dirac-exact relativistic methodology suggest that the effect of the changing size of the Au nucleus in different isotopomers can be observed for Au-containing molecules, for which the predicted quadrupole anomaly reaches values of the order of 0.1%. This is experimentally detectable and provides an insight into the charge distribution of non-spherical nuclei.

Filatov, Michael; Zou, Wenli; Cremer, Dieter

2012-10-01

18

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

19

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

20

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

21

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

22

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.

Kellö, Vladimir; Sadlej, Andrzej J.

1999-11-01

23

Quadrupole splitting and isomer shifts in Te oxides investigated using nuclear forward scattering  

NASA Astrophysics Data System (ADS)

Nuclear forward scattering by 125Te is a viable alternative to conventional 125Te Mössbauer spectroscopy avoiding all source related issues. Using reference compounds with known hyperfine parameters and Te oxides exhibiting stereochemically active lone pairs, we show that nuclear forward scattering by 125Te can be reliably used to extract quadrupole splitting energy and relative isomer shift. The rough correlation between Te-Ocoordination and quadrupole splitting energy as put forward by Takeda and Greenwood (J. Chem. Soc. Dalton, 2207, 1975), is corroborated by the presented results.

Klobes, Benedikt; Barrier, Nicolas; Vertruyen, Benedicte; Martin, Christine; Hermann, Raphaël P.

2014-04-01

24

Investigation of the nuclear quadrupole interaction in ZnO by the method of perturbed angular correlations of nuclear radiations  

NASA Astrophysics Data System (ADS)

It has been demonstrated that the sign and magnitude of the nuclear quadrupole interaction in ZnO can be determined using perturbed angular correlations of nuclear radiations. Information on the magnitude of the nuclear quadrupole interaction for the 184-keV 67Zn level can be obtained from the observation of the gamma-gamma perturbed correlation of the directions for the 67Ga ? 67Zn decay, and information on the magnitude and sign of the nuclear quadrupole interaction can be derived from the experiment on the induced beta-gamma correlation of the directions for the 67Cu xrightarrow{{? ^ - }} 67Zn decay. The results of measurements have been interpreted using the calculation of the electric field gradient in the ZnO crystal by the full-potential linearized augmented plane wave method with the generalized gradient approximation of the exchange-correlation potential.

Denisenko, G. A.; Okhotnikov, K. S.

2010-03-01

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.; Žagar, V.; Zidanšek, A.; Blinc, R.

2006-12-01

26

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

NASA Technical Reports Server (NTRS)

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

Strow, L. L.

1980-01-01

27

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

28

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

29

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

NASA Astrophysics Data System (ADS)

The multiconfiguration Dirac-Hartree-Fock (MCDHF) model has been employed to calculate the atomic expectation values responsible for the hyperfine splittings of the 7s7pP1,23 and P11 levels of radium. Calculated electric field gradients, together with the experimental electric quadrupole hyperfine structure constants, allow us to extract a nuclear electric quadrupole moment Q(Ra223) of 1.21(0.03) barn. This value is in good agreement with the semiempirical determination based on neutral radium hyperfine and fine structure, but differs from the latest result from an alkali-like radium ion.

Biero?, Jacek; Pyykkö, Pekka

2005-03-01

30

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

31

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

PubMed

New, high-sensitivity and high-resolution spectroscopic and imaging methods may be developed by exploiting nuclear magneto-optic effects. A first-principles electronic structure formulation of nuclear electric quadrupole moment-induced Cotton-Mouton effect (NQCME) is presented for closed-shell atoms. In NQCME, aligned quadrupole moments alter the index of refraction of the medium along with and perpendicular to the direction of nuclear alignment. The roles of basis-set convergence, electron correlation, and relativistic effects are investigated for three quadrupolar noble gas isotopes: (21)Ne, (83)Kr, and (131)Xe. The magnitude of the resulting ellipticities is predicted to be 10(-4)-10(-6) rad/(M cm) for fully spin-polarized nuclei. These should be detectable in the Voigt setup. Particularly interesting is the case of (131)Xe, in which a high degree of spin polarization can be achieved via spin-exchange optical hyperpolarization. PMID:24320246

Fu, Li-juan; Rizzo, Antonio; Vaara, Juha

2013-11-14

32

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

NASA Astrophysics Data System (ADS)

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

Fu, Li-juan; Rizzo, Antonio; Vaara, Juha

2013-11-01

33

Nuclear Schiff moment in nuclei with soft octupole and quadrupole vibrations  

SciTech Connect

Nuclear forces violating parity and time reversal invariance (P,T-odd) produce P,T-odd nuclear moments, for example, the nuclear Schiff moment. In turn, this moment can induce the electric dipole moment in the atom. The nuclear Schiff moment is predicted to be enhanced in nuclei with static quadru pole and octupole deformation. The analogous suggestion of the enhanced contribution to the Schiff moment from the soft collective quadrupole and octupole vibrations in spherical nuclei is tested in this article in the framework of the quasiparticle random phase approximation with separable quadrupole and octupole forces applied to the odd {sup 217-221}Ra and {sup 217-221}Rn isotopes. In this framework, we confirm the existence of the enhancement effect due to the soft modes, but only in the limit when the frequencies of quadrupole and octupole vibrations are close to zero. According to the QRPA, in realistic cases the enhancement in spherical nuclei is strongly reduced by a small weight of the corresponding ''particle + phonon'' component in a complicated wave function of a soft nucleus. The perspectives of a better description of the structure of heavy soft nuclei are discussed.

Auerbach, N. [School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978 (Israel); Dmitriev, V. F.; Sen'kov, R. A. [Budker Institute of Nuclear Physics, Novosibirsk Ru-630090 (Russian Federation); Flambaum, V. V. [School of Physics, University of New South Wales, Sydney 2052 (Australia); Lisetskiy, A. [GSI, Theory Department, D-64291 Darmstadt (Germany); Zelevinsky, V. G. [National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824-1321 (United States)

2006-08-15

34

First principles investigation of19F* nuclear quadrupole interaction in fourth group tetrafluorides  

NASA Astrophysics Data System (ADS)

Using the Hartree-Fock-Roothaan procedure the nuclear quadrupole interactions of the19F (spin 5/2) nucleus in CF4, SiF4 and GeF4 are studied. The theoretical results explain within 10% the observed experimental measurements by the time-differential perturbed angular distribution technique, including the important feature of sharp decrease of the19F* nuclear quadrupole coupling constant in going from CF4 to SiF4, followed by an increase in going to GeF4, while a simple consideration of the ionic characters of the C-F, Si-F and Ge-F bonds together with Townes and Dailey theory would lead to a continuous decrease from CF4 to GeF4. The dependence of the results on the choice of basis sets and the role of many-body effects is discussed.

Cho, Hwa-Suck; Briere, Tina; Srinivas, Sudha; Russell, Christine; Gowri, G.; Pati, Ranjit; Das, T. P.; Frank, M.; Kreische, W.; Nielsen, K. Bonde

1995-12-01

35

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

36

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

37

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

38

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

39

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

NASA Astrophysics Data System (ADS)

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

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

2009-03-01

40

Nuclear Quadrupole Coupling Constants of Two Chemically Distinct Nitrogen Atoms in 4-Aminobenzonitrile  

PubMed Central

The rotational spectrum of 4-aminobenzonitrile in the gas phase between 2 and 8.5 GHz is reported. Due to the two chemically distinct nitrogen atoms, the observed transitions showed a rich hyperfine structure. From the determination of the nuclear quadrupole coupling constants, information about the electronic environment of these atoms could be inferred. The results are compared to data for related molecules, especially with respect to the absence of dual fluorescence in 4-aminobenzonitrile. In addition, the two-photon ionization spectrum of this molecule was recorded using a time-of-flight mass spectrometer integrated into the setup. This new experimental apparatus is presented here for the first time.

2014-01-01

41

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

42

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

43

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

44

Microwave spectrum, rs structure, dipole moment, and nuclear quadrupole coupling constant tensor of ethyl lodide  

NASA Astrophysics Data System (ADS)

Microwave spectra of ethyl iodide and its six isotopic species have been measured. A least-squares analysis of the observed frequencies gave rotational, quartic centrifugal distortion constants and the components of the nuclear quadrupole coupling constant tensor for all the seven isotopic species. The rs structure has been well established from the moments of inertia calculated from the observed rotational constants. The observed nuclear quadrupole coupling constant tensor in the inertial principal axes system could be transformed into that in its own principal axes system which gave the following conclusions. The tensor is roughly cylindrically symmetric around the z axis which is slightly deviated by about 56' from the C?I internuclear line. From the Stark effect measurements of several low J transitions for the three isotopic species, the dipole moments have been determined. For the normal species, ?a = 1.884(3) D, ?b = 0.598(10) D, and ?total = 1.976(5) D and the dipole moment makes an angle of 2°9' with the C?I bond.

Inagusa, Toshihiro; Fujitake, Masaharu; Hayashi, Michiro

1988-04-01

45

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

46

The complete iodine and nitrogen nuclear electric quadrupole coupling tensors for fluoroiodoacetonitrile determined by chirped pulse Fourier transform microwave spectroscopy.  

PubMed

Molecular pulsed jet, chirped-pulse Fourier transform microwave spectroscopy has been used to record 499 transitions for the title molecule. Measurements have been made in the 8-16 GHz regions. Vibrational and electronic ground state rotational constants A, B, and C have been obtained, together with centrifugal distortion terms. The complete iodine and nitrogen nuclear quadrupole coupling tensors have been determined for the first time. Quantum chemical calculations have been performed to aid with analyses and, in particular, to aid in determining the signs of the off-diagonal components of the nuclear quadrupole coupling tensors. An experimentally determined relative electronegativity scale for several polyhalomethyl groups is proposed. PMID:20095677

Grubbs, G S; Kadiwar, G; Bailey, W C; Cooke, S A

2010-01-14

47

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

48

Nuclear Quadrupole Interactions of FLUORIDE-19 in Graphite, Silicon, Germanium and Gallium Arsenide.  

NASA Astrophysics Data System (ADS)

Measurements of nuclear quadrupole interactions of ^{19}F^ {*} in graphite, silicon, germanium and gallium arsenide have been carried out; the electric field gradients (efgs) at F impurity sites have been compared with cluster model calculations using both Hartree-Fock (HF) and Density Functional Theory (DFT) formalisms. The technique of time-differential perturbed angular distributions of gamma-rays (TDPAD) was employed using the ^{19}F(p, p' )^{19}F^ {*} reaction to derive the efg parameters following the implantation into the hosts of ^ {19}F^{*} in its isomeric state at 197 keV (I^pi = 5/2^{+}, T_ {1/2} = 85 ns). For the case of highly oriented pyrolytic graphite (HOPG) the principal components of the electric field gradient and its asymmetry parameter were found to be | V_{zz}| = 3.24(14) times 10^{22} V/m^2 and eta = 0.16(3), respectively, in close agreement with the DFT predictions of V_{zz} = -3.09 times 10 ^{22} V/m^2 and eta = 0.13 obtained for ^{19}F at a site midway between the layers with point group symmetry C _{2h} and inter-layer spacing d = 3.70 A. As a test of shell model theories an attempt was made to detect the nuclear quadrupole moment Q of the first excited state of ^{22}Na ^{*} (E = 583 keV, I ^pi = 1^{+}, T_{1/2} = 243 ns). In this case the ^{19}F( alpha ,n)^{22}Na ^{*} reaction was used to implant ^{22}Na ^{*} nuclei into HOPG. However, no quadrupole interaction was detected, leading to the conclusion that | QV_{zz} | < 8.7(8) times 10^{20} bV/m^2 . Taking Q = 0.06 barns as the best theoretical estimate for the 583 keV state, we find that | V_{zz}| must be less than 8.7(8) times 10^ {20} V/m^2. In the ^{19}F implantation in silicon three sites were found corresponding to quadrupole frequencies 23.2(3) MHz, 35.2(3) MHz and 37.1(5) MHz. Both HF and DFT calculations are consistent with the assignment of interstitial antibonding and bond -centre sites for the first two interactions, with HF predictions of 23.4 MHz and 35.0 MHz, respectively. In the former case the F atom is located 1.81 A along a < 111> direction from a silicon atom; in the latter situation the Si-Si bond length is found to expand by 1.02 A from its normal lattice value. It is speculated that the third interaction, which occurs at only the 10% level, possibly arises from sites associated with a defect or other impurity. In germanium two quadrupole frequencies were detected, with nu_{Q1} = 27.5(3) MHz and nu_{Q2} = 33.0(4) MHz, while in gallium arsenide only a single interaction was observed, with nu_ {Q} = 27.7(3) MHz. In all cases the asymmetry parameter eta was close to or equal to zero. In the case of germanium nu_ {Q1} and nu_{Q2 } are tentatively ascribed to antibonding and bond-centre sites, respectively. In the antibonding configuration the fluorine is situated at 1.88 A along a < 111> direction from a germanium atom. For F at the bond-centre site the Ge-Ge bond length was found to increase by about 1 A from its normal lattice value. In gallium arsenide the single frequency nu _{Q} is consistent with DFT calculations yielding nu_{Q} = 28.0 MHz for F at an intrabond site with the fluorine situated at 1.37 A from the Ga and 2.40 A from the As atom. (Abstract shortened by UMI.).

Surono, Djoko

49

Microwave Spectrum, Structure, and Nuclear Quadrupole Coupling Constants of 1-Bromo-1-fluoroethane  

NASA Astrophysics Data System (ADS)

The microwave spectrum of 1-bromo-1-fluoroethane, CHBrF-CH 3 and CHBrF-CH 2D ( 79/81Br), has been studied for the first time from 8 to 41 GHz. A least-squares analysis of the observed a- and b-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 = 8979.428(5) MHz, B = 2883.898(3) MHz, C = 2310.535(3) MHz, ? J = 0.74(2) kHz, ? JK = 2.49(3) kHz, ? K = 5.3(5) kHz, ? J = 0.146(1) kHz, ? K = 2.75(4) kHz, ? aa = 493.49(29) MHz, ? bb - ? cc = -38.89(11) MHz, and ?? ab? = 161.8(28) MHz for the CH 79BrF-CH 3 species; A = 8979.257(5) MHz, B = 2859.072(3) MHz, C = 2294.572(3), ? J = 0.76(2) kHz, ? JK = 2.51(3) kHz, ? K = 4.5(4) kHz, ? J = 0.145(1) kHz, ? K = 2.70(4) kHz, ? aa = 412.42(27) MHz, ? bb - ? cc = -32.56 (11) MHz, and ?? ab? = 133.3(3) MHz for the CH 81BrF-CH 3 species. The structural parameters are calculated from the 24 observed rotational constants, and electronic properties of the carbon-bromine bond in 1-bromo-1-fluoroethane are evaluated from the observed nuclear quadrupole coupling constants. These molecular properties are compared with those of other related molecules. The molecular structure of 1-bromo-1-fluoroethane is found to be very close to that of 1,1-difluoroethane except for the C-Br bond.

Tatamitani, Yoshio; Kuwano, Susumu; Fuchigami, Kiyokatu; Oe, Sumio; Ogata, Teruhiko

1999-08-01

50

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

51

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

NASA Astrophysics Data System (ADS)

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

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

2011-03-01

52

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

53

Nuclear quadrupole interaction of111Cd on type-1 Cu-sites in blue copper proteins  

NASA Astrophysics Data System (ADS)

The nuclear quadrupole interaction (NQI) of111Cd substituted for Cu(II) on type-1 sites in blue copper proteins is characterized by high values of ?0 in the region of 300 Mrad/s, close to that for the catalytic zinc site in alcohol dehydrogenase. Type-1 Cu has usually two sulfur ligands and two nitrogen ligands and in some cases an oxygen ligand in either a distorted tetrahedral geometry or in a trigonal bipyramidal geometry. The near tetrahedral arrangement together with the ligand sphere containing the same number of sulfur ligands explains the value of ?0 in the blue copper proteins. The present work determined the partial NQI for methionine using the known structure of azurin. This value was then used in the angular overlap model to calculate the NQI for ascorbate oxidase the structure of which is also known and gave good agreement with experiment. NQI data for laccase and stellacyanin the structures of which are unknown, are also given.

Tröger, W.; Butz, T.; Danielsen, E.; Bauer, R.; Thoenes, U.; Messerschmidt, A.; Huber, R.; Canters, G. W.; den Blaauwen, T.

1993-03-01

54

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

55

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

56

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

57

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

58

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

59

Theory of nuclear quadrupole interaction in cadmium using a first-principles pseudopotential  

Microsoft Academic Search

The field gradient in cadmium metal is calculated using a first-principles pseudopotential and including antishielding effects for the conduction electrons in an ab initio manner. The calculated field gradient in combination with the quadrupole coupling constant from perturbed-angular-correlation measurements leads to a quadrupole moment of 0.71 barns in good agreement with an earlier value obtained using an adaptation to other

Michael D. Thompson; T. P. Das; Gheorghe Ciobanu

1979-01-01

60

Nitrogen nuclear quadrupole coupling constants and heavy atom substitution geometry of tert-butyl nitrite  

NASA Astrophysics Data System (ADS)

The microwave spectra of tert-butyl nitrite, including all of its heavy-atom singly substituted isotopomers, have been observed with a pulsed molecular beam microwave Fourier transform spectrometer. The analysis resulted in the following substitution structure parameters: r(O t?N) = 118.18(8) pm, r(N?O b) = 141.75(8) pm, r(O b?C ?) = 143.75(6) pm, r(C ??C i) = 152.34(3) pm, r(C ??C o) = 152.90(4) pm, ?(O tNO b) = 111.6(2)°, ?(NO bC ?) = 111.8(2)°, ?(O bC ?C i) = 103.0(1)° ?(O bC ?C o) = 110.1(1)°, and ?(NO bC ?C o) = 61.6(1)°. The molecule has an ab-plane of symmetry. All measurements on the isotopically labeled species have been made using the isotopomers in their natural abundances. From the nuclear quadrupole hyperfine structures of the normal isotopic species and the [ 13C i]-labeled species, the elements of the nitrogen coupling tensor and its orientation in the bond axis system of the molecule have been determined to be ?zz = -5.53(17) MHz, ?xx = +2.15(17) MHz, ?yy = +3.377(1) MHz, and ?( a, x) = 24.3(13)°. Thus, the z-axis of the coupling tensor is inclined to the bisector of the O tNO b-angle by about 16.5° toward the O t?N-bond.

Heineking, N.; Jäger, W.; Gerry, M. C. L.

1992-10-01

61

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

62

Understanding China's Nuclear Non-Proliferation Policy.  

National Technical Information Service (NTIS)

China's nuclear-export activities appear to contradict its official non-proliferation policy. Scrutiny of China's nuclear exports and non- proliferation commitments indicate an adherence to strict 'letter-of-the-law' obligations. Yet, China's commitment t...

P. J. Nichols

1999-01-01

63

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

64

Nuclear energy and sustainability: Understanding ITER  

Microsoft Academic Search

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

Karine Fiore

2006-01-01

65

Rotational spectra, nuclear quadrupole hyperfine tensors, and conformational structures of the mustard gas simulent 2-chloroethyl ethyl sulfide  

NASA Astrophysics Data System (ADS)

Rotational spectra have been recorded for both the 35Cl and 37Cl isotopic forms of two structural conformations of 2-chloroethyl ethyl sulfide (CEES). The rotational constants of the 35Cl and 37Cl isotopomers were used to identify the conformational isomers. A total of 236 hyperfine transitions have been assigned for 47 rotational transitions of the 35Cl isotope of a GGT conformer, and 146 hyperfine have been assigned for 37 rotational transitions of the 37Cl isotopomer. For the second conformer, a total of 128 (110) hyperfine and 30 (28) rotational transitions have also been assigned to the 35Cl ( 37Cl) isotopes of a TGT conformation. The extensive hyperfine splitting data, measured to high resolution with a compact Fourier transform microwave spectrometer, were used to determine both the diagonal and off-diagonal elements of the 35Cl and 37Cl nuclear quadrupole coupling tensors in the inertial tensor principal axis system. The experimental rotational constant data, as well as the 35Cl and 37Cl nuclear quadrupole coupling tensors, were compared to the results from 27 optimized ab initio (HF/6-311++G ?? and MP2/6-311++G ??) model structures.

Tubergen, M. J.; Lesarri, A.; Suenram, R. D.; Samuels, A. C.; Jensen, J. O.; Ellzy, M. W.; Lochner, J. M.

2005-10-01

66

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 (? ˜0·06 and ?˜0·16) 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.

67

Density functional calculations of nuclear quadrupole coupling constants in the zero-order regular approximation for relativistic effects  

NASA Astrophysics Data System (ADS)

The zeroth-order regular approximation (ZORA) is used for the evaluation of the electric field gradient, and hence nuclear quadrupole coupling constants, in some closed shell molecules. It is shown that for valence orbitals the ZORA-4 electron density, which includes a small component density (``picture-change correction''), very accurately agrees with the Dirac electron density. For hydrogen-like atoms exact relations between the ZORA-4 and Dirac formalism are given for the calculation of the electric field gradient. Density functional (DFT) calculations of the electric field gradients for a number of diatomic halides at the halogen nuclei Cl, Br, and I and at the metallic nuclei Al, Ga, In, Th, Cu, and Ag are presented. Scalar relativistic effects, spin-orbit effects, and the effects of picture-change correction, which introduces the small component density, are discussed. The results for the thallium halides show a large effect of spin-orbit coupling. Our ZORA-4 DFT calculations suggest adjustment of some of the nuclear quadrupole moments to Q(79Br)=0.30(1) barn, Q(127I)=-0.69(3) barn, and Q(115In)=0.74(3) barn, which should be checked by future highly correlated ab initio relativistic calculations. In the copper and silver halides the results with the used gradient corrected density functional are not in good agreement with experiment.

van Lenthe, Erik; Jan Baerends, Evert

2000-05-01

68

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

69

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

70

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

71

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

72

Rotational spectra, nuclear quadrupole coupling tensors, and structures for CF3CF2X, X = Cl, Br  

NASA Astrophysics Data System (ADS)

A chirped pulse Fourier transform microwave spectrometer was used to obtain pure rotational spectra for CF3CF2Cl between 8 GHz and 16 GHz, and for CF3CF2Br between 8 GHz and 14 GHz. In both cases rotational constants, quartic centrifugal distortion constants and chlorine/bromine nuclear electric quadrupole coupling tensors were obtained for the first time. For both compounds only the trans conformer was observed. Quantum chemical calculations have provided structures with rotational constants closely matching the experimental values. For CF3CF2Br the spectra collected were sufficiently strong that the C-13 isotopologues could be observed in natural abundance. ?J = 2 transitions were observed in the rotational spectrum of CF3CF2Br, but were not observed in the spectrum for CF3CF2Cl.

Long, B. E.; Grubbs, G. S.; Langridge, J. D.; Cooke, S. A.

2012-09-01

73

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

Pérez, Silvina; Wolfenson, Alberto

2012-02-01

74

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; Forsén, Sture; Lilja, Hans

75

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

76

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

77

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

78

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

79

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

80

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

81

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

82

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.; Krämer, S.; Tallon, J. L.; Dupree, R.; Loram, J. W.

2005-05-01

83

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

NASA Astrophysics Data System (ADS)

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

Wang, Qiaoming; Collins, Gary S.

2013-05-01

84

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

NASA Technical Reports Server (NTRS)

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

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

1990-01-01

85

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

NASA Technical Reports Server (NTRS)

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

Norbury, John W.

1992-01-01

86

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

87

Quadrupole moment of the 6- isomeric state in 66Cu: Interplay between different nuclear deformation driving forces  

NASA Astrophysics Data System (ADS)

We have measured the spectroscopic quadrupole moment of the 6 isomeric state in 66Cu to be |Q|=18.6(12) efm. This state results from a weak coupling of the ?p and the ?g orbitals, which lead to sizable deformation at oblate and prolate shapes, correspondingly, in the 68Ni region. The interplay between these two different deformation-driving orbitals is observed at N=37 for the 6 state resulting in a most probable oblate shape.

Lozeva, R. L.; Balabanski, D. L.; Georgiev, G.; Daugas, J.-M.; Péru, S.; Audi, G.; Cabaret, S.; Faul, T.; Ferraton, M.; Fiori, E.; Gaulard, C.; Ibrahim, F.; Morel, P.; Risegari, L.; Verney, D.; Yordanov, D. T.

2011-01-01

88

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

89

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 Néel 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

90

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

91

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

92

Nuclear Propulsion for Space, Understanding the Atom Series.  

ERIC Educational Resources Information Center

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

Corliss, William R.; Schwenk, Francis C.

93

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

94

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

NASA Astrophysics Data System (ADS)

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

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

1998-03-01

95

Sources of Nuclear Fuel, Understanding the Atom Series.  

ERIC Educational Resources Information Center

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

Singleton, Arthur L., Jr.

96

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

PubMed

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

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

2012-11-01

97

Understanding electron and nuclear spin dynamics in Cr^5+ doped K3NbO8  

NASA Astrophysics Data System (ADS)

Chromium(V) doped in the diamagnetic host potassium niobate, a simple spin S=.5ex1-.1em/ -.15em.25ex2 , I = 0 system, has been proposed as an alternative standard for field calibration and g-standard for high-field EPR [1]. This system constitutes a dilute two-level model relevant for use as a electron spin qubit [2] and as such coherent electron spin manipulation at X-band (˜9.5 GHz) was observed over a wide range temperature. Rabi oscillations are observed for the first time in a spin system based on transition metal oxides up to room temperature. At 4 K, a Rabi frequency ?R of 20 MHz together with the phase coherence relaxation (spin-spin relaxation) time, T2 of ˜10 ?s results in the single qubit figure of merit QM (=?RT2/?) as about 500, showing that a diluted ensemble of Cr(V) (S = 1/2) doped K3NbO8 is a potential candidate for solid-state quantum information processing. Also, the field and temperature dependence of the T1 (spin-lattice relaxation) and T2 times was investigated [3] for a further understanding of the relaxation mechanisms governing the phase decoherence in this system. These studies show that the coupling of the electron spin with the neighboring ^39K nuclei (I = 3/2) is one of the prominent T2 mechanisms. The hyperfine and quadrupole interactions with ^39K nuclei was resolved by using the high-frequency (240 GHz) pulsed electron nuclear double resonance (ENDOR). [3pt] [1]. B. Cage, A. Weekley, L. -C. Brunel and N. S. Dalal, Anal. Chem. 71, 1951 (1999). [0pt] [2]. S. Nellutla, K.-Y. Choi, M. Pati, J. van Tol, I. Chiroescu and N. S. Dalal, Phys. Rev. Lett. 99, 137601 (2007). [0pt] [3]. S. Nellutla, G. W. Morley, M. Pati, N. S. Dalal and J. van Tol, Phys. Rev. B. 78, 054426 (2008).

Nellutla, Saritha

2009-03-01

98

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

99

Toward Understanding the Microscopic Origin of Nuclear Clustering  

SciTech Connect

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

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

2013-01-01

100

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

NASA Astrophysics Data System (ADS)

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

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

2013-02-01

101

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

102

Electric field gradients and nuclear quadrupole coupling constants of isonitriles obtained from Moller-Plesset and quadratic configuration interaction calculations  

Microsoft Academic Search

Coupled cluster, nth-order Moller-Plesset perturbation and quadratic configuration interaction theories are used to calculate the electric field gradients and nuclear quadruple coupling constants of 12 nitrogen-containing molecules using laser sets of valence DZ + P and TZ + P. These molecules are: HCN, HNC, CHâNC, CFâNC, NCNC, HCCNC, FCHâNC, FâCHNC, CHâCHâNC, HâCCH, NC, and NCCCHâNC. 52 refs., 4 figs., 5

Dieter Cremer; Michael Krueger

1992-01-01

103

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

SciTech Connect

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

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

2011-05-06

104

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

105

Description of nuclear octupole and quadrupole deformation close to axial symmetry: Critical-point behavior of {sup 224}Ra and {sup 224}Th  

SciTech Connect

The model, introduced in a previous paper, for the description of the octupole and quadrupole degrees of freedom in conditions close to axial symmetry, is applied to situations of shape phase transitions where the quadrupole amplitude can reach zero. The transitional nuclei {sup 224,226}Ra and {sup 224}Th are discussed in the frame of this model. Their level schemes can be reasonably accounted for by assuming a square-well potential in two dimensions. Electromagnetic transition amplitudes are also evaluated and compared with existing experimental data.

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

2008-02-15

106

Nuclear Quadrupole Tensors for (35)Cl and (37)Cl in cis-1-chloro-2-fluoroethylene Obtained by Detection of Perturbation-Allowed DeltaJ = 2 and DeltaJ = 3 Transitions.  

PubMed

The nuclear quadrupole hyperfine structure in rotational transitions of cis-1-chloro-2-fluoroethylene was measured for both (35)Cl and (37)Cl containing isotopomers in the millimeter-wave region. Near degeneracies of the 9(3,7) and 10(2,9) levels of (35)ClHC&dbond;CFH and of the 19(9,10/11) and 17(10,7/8) levels of (37)ClHC&dbond;CFH cause strong perturbations of the hyperfine patterns and give rise to perturbation-allowed DeltaJ = 2 and DeltaJ = 3 transitions. Lamb-dip measurements of such perturbed hyperfine patterns and of forbidden DeltaJ = +2 and perturbation-enhanced DeltaJ = 0 transitions of (35)ClHC&dbond;CFH provided an accurate determination of chi(ab), the off-diagonal element of the inertial nuclear quadrupole tensor. For (37)ClHC&dbond;CFH, chi(ab) was determined for the first time thanks to the observation of perturbed hyperfine patterns and of forbidden DeltaJ = +3 and DeltaJ = -2 transitions. Additional measurements of hyperfine structures led to improved values for the diagonal elements of the chi tensor of both (35)Cl and (37)Cl. Moreover, the complete inertial nuclear quadrupole tensor was evaluated from the field gradient at the chlorine nucleus computed by using the Multi-Configuration Self-Consistent Field (MCSCF) approach and employing basis sets of triple-zeta quality: very good agreement with the experiment was obtained. Copyright 2000 Academic Press. PMID:11148094

Dore; Puzzarini; Cazzoli; Gambi

2000-12-01

107

UnLINCing the nuclear envelope: towards an understanding of the physiological significance of nuclear positioning.  

PubMed

Appropriate tissue morphogenesis strictly requires the developmental regulation of different types of nuclear movements. LINC (linker of nucleoskeleton and cytoskeleton) complexes are macromolecular scaffolds that span the nuclear envelope and physically connect the nuclear interior to different cytoskeletal elements and molecular motors, thereby playing essential roles in nucleokinesis. Recent studies dedicated to the in vivo disruption of LINC complexes not only confirmed their widespread role in nuclear dynamics, but also led to a vigorous regain of interest in the physiological relevance of nuclear positioning within cells and syncitia. In the present paper, we review the results of LINC complex disruption in vivo across different organisms and the potential implications of observed phenotypes in human diseases. PMID:22103527

Razafsky, David; Zang, Shulun; Hodzic, Didier

2011-12-01

108

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

SciTech Connect

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

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

2007-01-03

109

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

110

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

Microsoft Academic Search

Monolithic nuclear fuel is currently being developed for use in research reactors, and friction bonding (FB) is a technique being developed to help in this fuels fabrication. Since both FB and monolithic fuel are new concepts, research is needed to understand the impact of varying FB fabrication parameters on fuel plate characteristics. This thesis research provides insight into the FB

Karen L. Shropshire

2008-01-01

111

Three-dimensional nuclear chart—understanding nuclear physics and nucleosynthesis in stars  

NASA Astrophysics Data System (ADS)

Three-dimensional (3D) nuclear charts were created using toy blocks, which represent the atomic masses per nucleon number and the total half-lives for each nucleus in the entire region of the nuclear mass. The bulk properties of the nuclei can be easily understood by using these charts. Subsequently, these charts were used in outreach activities for the general public and high school students. As an example, an application for a lecture on nucleosynthesis in stars is introduced, and some explanations for the abundance of iron and the origin of uranium and heavy elements on the Earth are given with the 3D chart.

>Hiroyuki Koura,

2014-03-01

112

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

113

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

114

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

115

Nuclear hyperfine and quadrupole tensor characterization of the nitrogen hydrogen bond donors to the semiquinone of the QB site in bacterial reaction centers: a combined X- and S-band (14,15)N ESEEM and DFT study.  

PubMed

The secondary quinone anion radical QB(-) (SQB) in reaction centers of Rhodobacter sphaeroides interacts with N? of His-L190 and Np (peptide nitrogen) of Gly-L225 involved in hydrogen bonds to the QB carbonyls. In this work, S-band (?3.6 GHz) ESEEM was used with the aim of obtaining a complete characterization of the nuclear quadrupole interaction (nqi) tensors for both nitrogens by approaching the cancelation condition between the isotropic hyperfine coupling and (14)N Zeeman frequency at lower microwave frequencies than traditional X-band (9.5 GHz). By performing measurements at S-band, we found a dominating contribution of N? in the form of a zero-field nqi triplet at 0.55, 0.92, and 1.47 MHz, defining the quadrupole coupling constant K = e(2)qQ/4h = 0.4 MHz and associated asymmetry parameter ? = 0.69. Estimates of the hyperfine interaction (hfi) tensors for N? and Np were obtained from simulations of 1D and 2D (14,15)N X-band and three-pulse (14)N S-band spectra with all nuclear tensors defined in the SQB g-tensor coordinate system. From simulations, we conclude that the contribution of Np to the S-band spectrum is suppressed by its strong nqi and weak isotropic hfi comparable to the level of hyperfine anisotropy, despite the near-cancelation condition for Np at S-band. The excellent agreement between our EPR simulations and DFT calculations of the nitrogen hfi and nqi tensors to SQB is promising for the future application of powder ESEEM to full tensor characterizations. PMID:24437652

Taguchi, Alexander T; O'Malley, Patrick J; Wraight, Colin A; Dikanov, Sergei A

2014-02-13

116

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

SciTech Connect

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

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

2010-03-15

117

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

NASA Astrophysics Data System (ADS)

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

Clement, R.

118

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

SciTech Connect

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

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

2009-01-01

119

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

120

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

SciTech Connect

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

Karen L. Shropshire

2008-04-01

121

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

122

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

123

Understanding and Managing Aging of Spent Nuclear Fuel and Facility Components in Wet Storage  

SciTech Connect

Storage of nuclear fuel after it has been discharged from reactors has become the leading spent fuel management option. Many storage facilities are being required to operate longer than originally anticipated. Aging is a term that has emerged to focus attention on the consequences of extended operation on systems, structures, and components that comprise the storage facilities. The key to mitigation of age-related degradation in storage facilities is to implement effective strategies to understand and manage aging of the facility materials. A systematic approach to preclude serious effects of age-related degradation is addressed in this paper, directed principally to smaller facilities (test and research reactors). The first need is to assess the materials that comprise the facility and the environments that they are subject to. Access to historical data on facility design, fabrication, and operation can facilitate assessment of expected materials performance. Methods to assess the current condition of facility materials are summarized in the paper. Each facility needs an aging management plan to define the scope of the management program, involving identification of the materials that need specific actions to manage age-related degradation. For each material identified, one or more aging management programs are developed and become part of the plan Several national and international organizations have invested in development of comprehensive and systematic approaches to aging management. A method developed by the US Nuclear Regulatory Commission is recommended as a concise template to organize measures to effectively manage age-related degradation of storage facility materials, including the scope of inspection, surveillance, and maintenance that is needed to assure successful operation of the facility over its required life. Important to effective aging management is a staff that is alert for evidence of materials degradation and committed to carry out the aging management programs.

Johnson, A. Burton

2007-07-01

124

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

SciTech Connect

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

Vienna, John D. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Ryan, Joseph V. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Gin, Stephane [CEA Marcoule, DTCD SECM, Bagnols-sur-Ceze (France); Inagaki, Yaohiro [Dept. of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Fukuoda (Japan)

2013-12-05

125

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

126

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

127

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

128

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

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

129

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

130

Quadrupole interactions in tetraoxoferrates (VI)  

NASA Astrophysics Data System (ADS)

An applicability of the point charge approach for calculations of quadrupole splittings in Mössbauer 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

131

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

132

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.

133

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

134

A Crowdsourced nucleus: understanding nuclear organization in terms of dynamically networked protein function.  

PubMed

The spatial organization of the nucleus results in a compartmentalized structure that affects all aspects of nuclear function. This compartmentalization involves genome organization as well as the formation of nuclear bodies and plays a role in many functions, including gene regulation, genome stability, replication, and RNA processing. Here we review the recent findings associated with the spatial organization of the nucleus and reveal that a common theme for nuclear proteins is their ability to participate in a variety of functions and pathways. We consider this multiplicity of function in terms of Crowdsourcing, a recent phenomenon in the world of information technology, and suggest that this model provides a novel way to synthesize the many intersections between nuclear organization and function. This article is part of a Special Issue entitled: Chromatin and epigenetic regulation of animal development. PMID:24412853

Wood, Ashley M; Garza-Gongora, Arturo G; Kosak, Steven T

2014-03-01

135

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

136

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

SciTech Connect

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

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

2007-07-01

137

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

NASA Astrophysics Data System (ADS)

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

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

2007-05-01

138

Application of Nuclear Microprobes towards Understanding Complex Ore Geo-electrochemistry  

NASA Astrophysics Data System (ADS)

We report on recent development on the CSIRO Nuclear Microprobe (NMP) towards catering for long exposure mapping required for large area scanning. A new data collection system based on Labview FPGA highly co-ordinated with beam transport sits at the heart of the upgrade. These upgrades are discussed and an example of the systems use for ?-Particle Induced X-ray Emission (PIXE) analysis in the area of complex ore geo-electrochemistry is briefly described.

Laird, J. S.; Szymanski, R.; Large, R.; Ryan, C. G.

2012-10-01

139

Towards understanding the epigenetics of transcription by chromatin structure and the nuclear matrix  

PubMed Central

Summary The eukaryotic nucleus houses a significant amount of information that is carefully ordered to ensure that genes can be transcribed as needed throughout development and differentiation. The genome is partitioned into regions containing functional transcription units, providing the means for the cell to selectively activate some, while keeping other regions of the genome silent. Over the last quarter of a century the structure of chromatin and how it is influenced by epigenetics has come into the forefront of modern biology. However, it has thus far failed to identify the mechanism by which individual genes or domains are selected for expression. Through covalent and structural modification of the DNA and chromatin proteins, epigenetics maintains both active and silent chromatin states. This is the “other” genetic code, often superseding that dictated by the nucleotide sequence. The nuclear matrix is rich in many of the factors that govern nuclear processes. It includes a host of unknown factors that may provide our first insight into the structural mechanism responsible for the genetic selectivity of a differentiating cell. This review will consider the nuclear matrix as an integral component of the epigenetic mechanism.

Martins, Rui Pires; Krawetz, Stephen A.

2010-01-01

140

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

141

An electron spin-echo envelope modulation study of 14N nuclear hyperfine and quadrupole coupling in copper(II)/nickel(II) bis N,N-di- n-butyl-dithiocarbamate)  

NASA Astrophysics Data System (ADS)

The electron spin-echo envelope modulation technique (ESEEM) is used to determine the 14N hyperfine and quadrupole tensors in copper-doped nickel(II) bis( N,N-di- n-butyl-dithiocarbamate). The line positions and peak intensities of the Fourier-transformed ESEEM spectra are interpreted using simulated spectra, obtained by diagonalizing the full spin-Hamiltonian matrix. The 14N quadrupole tensor can be accounted for theoretically by extended Hückel molecular orbital calculations. For the interpretation of the 14N hyperfine tensor, however, an unrestricted molecular orbital calculation is necessary. Therefore, one should be cautions in drawing conclusions about spin-density distributions from small hyperfine couplings of nuclei in higher coordination spheres.

Reijerse, E. J.; Paulissen, M. L. H.; Keijzers, C. P.

142

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

PubMed Central

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

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

2012-01-01

143

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

144

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

NASA Astrophysics Data System (ADS)

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

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

2013-01-01

145

Short-range nuclear structure and the EMC effect: understanding the connection  

NASA Astrophysics Data System (ADS)

Inclusive electron scattering has proven to be an exceptional tool for studying short range structure in nuclei. Measurements of the EMC effect (at x < 1) are aimed at studying in-medium modification of the nucleon structure functions. On the other hand, inclusive measurements at x>1 focus on short range correlations (SRCs) between nucleons. Recent data on the EMC effect from Jefferson Lab suggest a sensitivity to short range nuclear structure related to NN correlations at x>1. The high precision results on the EMC effect and the ratios at x>1 have a linear relationship, suggesting a common physics explanation. Results from both experiments will be reviewed, the meaning of the correlation explored, plans for future measurements will be discussed.

Fomin, Nadia

2013-04-01

146

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

SciTech Connect

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

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

1990-05-01

147

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

148

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

NASA Astrophysics Data System (ADS)

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

Cawthorne, Samantha; Collins, Gary S.

2009-11-01

149

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

150

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

151

Study of a soft quadrupole excitation in the nucleus [sup 11]Li: A phase space model of neutron halo nuclei  

SciTech Connect

Quadrupole excitations in the nucleus [sup 11]Li have been studied in a semiclassical framework using the nuclear Vlasov equation solved with the test particle method. A soft mode of quadrupole excitation located around 2 MeV is found. The strength (in percentage of the energy-weighted sum rule) exhausted in such a soft quadrupole excitation region is very sensitive to the extension of the neutron halo in the nucleus [sup 11]Li. The results are discussed in comparison with other recent calculations. The use of the collective response to tune phase-space models of neutron excess nuclei to be used in collision dynamics is finally stressed.

Yanhuang, C.; Smerzi, A.; Di Toro, M. (China Center of Advanced Science and Technology (World Laboratory), P.O. Box 8730, Beijing, 100080 (China) Institute of Nuclear Research, Academia Sinica, P.O. Box 800204, Shanghai 201800 (China) INFN-Laboratorio Nazionale del Sud and Dipartimento di Fisica, 57, Corso Italia, 95129 Catania (Italy))

1994-12-01

152

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

153

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

154

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

155

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

156

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

157

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

158

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

159

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

160

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

161

Molecular dynamic simulation of quadrupole relaxation of atomic ions in aqueous solution  

Microsoft Academic Search

Molecular dynamics (MD) simulations were performed in order to investigate the molecular origin of the nuclear quadrupole relaxation mechanism for Li+, Na+, and Cl? ions in dilute aqueous solution. Different boundary conditions were investigated in the simulations, but neither the boundary conditions nor the system size have any significant effect on the different time correlation functions (tcf:s) calculated. It is

Roger W. Impey

1984-01-01

162

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

163

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

NASA Astrophysics Data System (ADS)

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

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

2013-05-01

164

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

165

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

166

Microwave Spectrum, Structural Parameters and Quadrupole Coupling for Azaborine and 1-ETHYL-AZABORINE  

NASA Astrophysics Data System (ADS)

The first microwave spectra for the unusual and elusive aromatic molecules, 1,2-dihydro-1,2-azaborine (azaborine) and 1-ethyl-azaborine have been measured, in the 7-18 GHz range, providing accurate rotational constants, nitrogen and boron quadrupole coupling strengths, important bond lengths and other structural parameters. Azaborine (BNC_4H_6)is an aromatic, B-N substituted analog of benzene, the quintessential aromatic molecule. The experimental bond lengths determined for azaborine are: R(B-N) = 1.45(3) Å, R(B-C) = 1.51(1) Å, and R(N-C) = 1.37(3) Å. Accurate measurements of 14N, 11B, and 10B nuclear quadrupole coupling were obtained. The inertial defect ? = 0.02 amu Å^2 indicating a planar structure. A Townes-Dailey population analysis of the B and N quadrupole coupling constants provided the valence p-electron occupancy

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

2010-06-01

167

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

168

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

169

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.; Mané, E.; Morris, G. D.; Shelbaya, O. T. J.; Song, Q.; Wang, D.

2014-01-01

170

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

171

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.

Çelik, Gültekin; Gökçe, Yasin; Y?ld?z, Murat

2014-05-01

172

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

173

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

PubMed

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

Rose, Katrin; Cottenier, Stefaan

2012-08-28

174

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

175

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

176

Hydrogen isotope analysis by quadrupole mass spectrometry  

Microsoft Academic Search

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

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

1981-01-01

177

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

178

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

179

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

180

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

181

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

182

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

Microsoft Academic Search

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

Sean Ekins; Leonid Mirny; Erin G. Schuetz

2002-01-01

183

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

Microsoft Academic Search

Failures in the basic materials used in nuclear power plants continue to be costly and insidious, despite increasing industry vigilance to catch failures before they degrade safety. For instance, the overall costs to the US industry from materials problems could amount to as much as $10 billion annually. Moreover, estimates indicate that the cost of a pipe failure in a

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

1990-01-01

184

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

185

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

186

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

187

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

188

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

Microsoft Academic Search

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

M. Eibschütz; M. E. Lines

1982-01-01

189

Quadrupole collective dynamics of medium–heavy even–even nuclei within the highly truncated diagonalization approach  

NASA Astrophysics Data System (ADS)

The seven scalar functions defining a Bohr quadrupole collective Hamiltonian are evaluated from calculations performed within the highly truncated diagonalization approach (HTDA) for four even-even medium-heavy nuclei. The collective nuclear spectra so obtained are discussed and compared with similar previous theoretical results and available experimental data.

Imadalou, M.; Medjadi, D. E.; Quentin, P.; Próchniak, L.

2014-05-01

190

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

PubMed

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

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

2011-10-01

191

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

192

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 Møller-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

193

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

194

Nuclear Schiff moment and soft vibrational modes  

SciTech Connect

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

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

2008-07-15

195

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

196

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

197

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

198

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

199

Relative quadrupole moments of exotic shapes at ultrahigh spin in 154Er: calibrating the TSD/SD puzzle  

NASA Astrophysics Data System (ADS)

Transition quadrupole moments, Qt, of two ultrahigh-spin, collective structures in 154Er have been measured for the first time using the Doppler Shift Attenuation Method (DSAM). Data were acquired at the ATLAS accelerator facility of Argonne National Laboratory, using the Gammasphere detector array. A thick, gold-backed 110Pd foil was bombarded by a beam of 48Ti ions at 215 MeV. The Qt for each band was determined from the Doppler shift of gamma rays emitted by the resulting recoil nuclei. The extracted transition quadrupole moments are significantly different in magnitude, suggesting the two structures in 154Er represent distinct exotic nuclear shapes, namely axial superdeformed (SD) with Qt ? 20 eb, and triaxial strongly deformed (TSD) with Qt ? 11 eb. Indeed, the results calibrate the quadrupole moments of TSD bands recently measured in light erbium nuclei, 157,158Er.

Revill, J. P.; Paul, E. S.; Wang, X.; Riley, M. A.; Simpson, J.; Ollier, J.; Boston, A. J.; Carpenter, M. P.; Chiara, C. J.; Hoffman, C.; Janssens, R. V. F.; Kondev, F. G.; Lauritsen, T.; Nolan, P. J.; Rees, J. M.; Rigby, S. V.; Unsworth, C.; Zhu, S.; Ragnarsson, I.

2012-09-01

200

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

201

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

202

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

203

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

204

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

205

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

206

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

207

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

208

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

209

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

210

The first quadrupole excitations in spherical nuclei and nuclear pairing  

NASA Astrophysics Data System (ADS)

Excitation energies and transition probabilities of the first 2+ excitations in even lead, tin and nickel isotopes are calculated within the self-consistent Theory of Finite Fermi Systems based on the Energy Density Functional by Fayans et al. A reasonable agreement with available experimental data is obtained. The effect of the density dependence of the effective pairing interaction is analyzed in detail by comparing results obtained with volume and surface pairing. The effect is found to be noticeable, especially for the 2+-energies which are systematically higher at 200-300 keV for the volume paring as compared with the surface pairing case, the latterbeing in a better agreement with the data.

Tolokonnikov, S. V.; Kamerdzhiev, S.; Krewald, S.; Saperstein, E. E.; Voitenkov, D.

2012-12-01

211

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

212

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

213

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

214

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

215

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

216

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

SciTech Connect

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

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

2007-09-15

217

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

218

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

PubMed

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

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

2010-04-21

219

Quadrupole beam-based alignment in the RHIC interaction regions  

SciTech Connect

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

Ziegler, J.; Satogata, T.

2011-03-28

220

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.

Gökçe, Yasin; Çelik, Gültekin; Y?ld?z, Murat

2014-07-01

221

Nuclear  

NSDL National Science Digital Library

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

Project, Iowa P.

2004-01-01

222

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

223

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

224

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

225

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

226

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

227

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

228

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

229

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

230

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

231

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

232

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

233

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

NASA Astrophysics Data System (ADS)

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

Prat, Eduard; Aiba, Masamitsu

2014-05-01

234

Understanding Coronaviruses  

MedlinePLUS

... Field Search Button Advanced Search NIAID Home Health & Research Topics Labs & Scientific Resources Funding About NIAID News & Events NIAID > Health & Research Topics > Coronaviruses > Understanding Coronaviruses Coronaviruses Understanding Coronaviruses Overview Symptoms ...

235

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

236

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

237

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

SciTech Connect

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

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

2011-07-15

238

Interfacial complexation reactions of Sr2+ with octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide for understanding its extraction in reprocessing spent nuclear fuels.  

PubMed

The complexation reactions between strontium (Sr(2+)) and octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) were studied at the aqueous|1,2-dichloroethane (w|DCE) and aqueous|room-temperature ionic liquid (w|RTIL) microinterfaces, in order to understand its extraction in reprocessing spent nuclear fuels, remediation of environmental contamination, and potential radiological isotope feed stock for (90)Y from its isotope (90)Sr in fission byproducts. The stoichiometry (or metal to ligand ratios) and overall complexation constant (?) for these reactions at these two interfaces are described herein. Two stoichiometries at the w|DCE interface were discovered, that is, [Sr(CMPO)(2)](2+) and [Sr(CMPO)(3)](2+) with ? values of 4.5×10(19) and 5.5×10(25), respectively. Only one stoichiometry was observed at the w|RTIL interface: [Sr(CMPO)(3)](2+) with ? equal to 1.5×10(34). The larger complexation constant for [Sr(CMPO)(3)](2+) at the w|RTIL interface than those found at the w|DCE interface supported the previous observation of a greater distribution ratio in the aqueous-RTIL metal extraction than that in the aqueous-alkane processing. The kinetics of the reactions at the w|RTIL interface was slow. The stoichiometries at the w|DCE interface were confirmed using biphasic electrospray ionization mass spectrometry (BESI-MS) as well as direct injection of Sr(2+) and CMPO mixture by means of a "shaking flask" experiment to conventional ESI-MS. PMID:22025385

Stockmann, Tom J; Lu, Yu; Zhang, Jing; Girault, Hubert H; Ding, Zhifeng

2011-11-18

239

Assessing Understanding  

NSDL National Science Digital Library

Try using an assessment cycle to effectively probe students' understanding of scientific concepts. The diagnostic, formative, summative, and confirmatory assessment can be embedded into any unit of study.

Sterling, Donna R.

2005-01-01

240

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

241

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

242

User Understanding.  

ERIC Educational Resources Information Center

This document presents hypotheses about how much understanding a user needs to perform skillfully using a computer or a computer program. A framework for characterizing user understanding is presented which includes three criteria for evaluating the representation generated during problem solving: (1) internal coherence--whether the components of…

Riley, Mary S.

243

Understanding Waves  

NSDL National Science Digital Library

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

2010-01-01

244

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

245

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

246

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

247

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

248

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

249

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

250

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

251

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

252

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

253

Understanding Nano  

NSDL National Science Digital Library

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

2013-07-05

254

Understanding Alzheimer's  

MedlinePLUS

... Navigation Bar Home Current Issue Past Issues Understanding Alzheimer's Past Issues / Fall 2007 Table of Contents For ... and brain scans. No treatment so far stops Alzheimer's. However, for some in the disease's early and ...

255

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

256

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

257

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

258

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

259

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

260

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

261

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

262

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

263

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

264

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

265

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

266

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

267

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

268

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

269

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

270

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

271

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

272

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

273

Understanding Science  

NSDL National Science Digital Library

The mission of Understanding Science is to provide a fun, accessible, and free resource that accurately communicates what science is and how it really works. The process of science is exciting, but standard explanations often miss its dynamic nature. Science affects us all everyday, but people often feel cut off from science. Science is an intensely human endeavor, but many portrayals gloss over the passion, curiosity, and even rivalries and pitfalls that characterize all human ventures. Understanding Science gives users an inside look at the general principles, methods, and motivations that underlie all of science.

2009-01-01

274

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

275

Understanding Islam.  

National Technical Information Service (NTIS)

The purpose of this study is to provide a better understanding of Islam to commanders and other military personnel who may be assigned to Islamic countries, be serving with persons following the Muslim faith, and those who would like to learn more about t...

C. H. Sydnor

1990-01-01

276

Understanding Ageing  

Microsoft Academic Search

A broad biological approach makes it possible to understand why ageing exists and also why different mammalian species have very different maximum longevities. The adult organism is maintained in a functional state by at least ten major mechanisms, which together comprise a substantial proportion of all biological processes. These maintenance mechanisms eventually fail, because the evolved physiological and anatomical design

Robin Holliday

1997-01-01

277

Understanding Data.  

ERIC Educational Resources Information Center

This article demonstrates how to construct two types of graphs, the line plot, and the stem and leaf plot. States that these graphing techniques improve students' ability to understand tabular data. An instructional model is presented for directing lessons which use the two types of graphs. (JDH)

McMann, Francis C.; McMann, Carolyn Jepsen

1987-01-01

278

Understanding Artworlds.  

ERIC Educational Resources Information Center

This curriculum unit consists of four lessons that are designed to broaden students' understanding of art and culture; each lesson can stand alone or be used in conjunction with the others. The introduction offers a conceptual framework of the Artworlds unit, which takes an inquiry-based approach. The unit's first lesson, "Worlds within Worlds,"…

Erickson, Mary; Clover, Faith

279

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

280

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

281

Interacting-boson-model and open-shell-Tamm-Dancoff-approximation interpretations of quadrupole collectivity  

NASA Astrophysics Data System (ADS)

The collective S-D states used by Otsuka, Arima, and Iachello in their microscopic theory of the interacting boson model are reinterpreted in terms of conventional concepts of collective motion. It is shown that a suitable seniority projected one-body excitation operator acting on a state composed of S and D pairs excites a new D pair. The excitation operator can be calculated using an open-shell Tamm-Dancoff method. The S-D states are then pictured as arising from many-quantum excitations of a single collective mode. NUCLEAR STRUCTURE IBM shell model subspace constructed; open-shell TDA excitation operator used. Seniority scheme, pairing, and quadrupole degrees of freedom for describing low energy collective motion.

Johnson, A. B.; Vincent, C. M.

1982-03-01

282

Hyperfine Structure and Nuclear Moments of 17Hr Bromine76  

Microsoft Academic Search

The nuclear spin, the nuclear magnetic-dipole interaction constant a, and the nuclear electric-quadrupole interaction constant b, have been determined for 17-hr bromine-76 by an atomic-beam experiment. The results are: I=1, |a|=345.422+\\/-0.014 Mc\\/sec, |b|=314.329+\\/-0.022 Mc\\/sec, ba=0.9100+\\/-0.0001. The nuclear magnetic-dipole and electric-quadrupole moments are calculated to be, respectively, mu=+\\/-0.5479+\\/-0.0001 nuclear magneton, and Q=-\\/+0.27+\\/-0.01 barn. The sign of mu, though not determined, is

Edgar Lipworth; Thomas M. Green; Hugh L. Garvin; William A. Nierenberg

1960-01-01

283

Understanding Flight  

SciTech Connect

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

Anderson, David

2001-01-31

284

Understanding resilience  

PubMed Central

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

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

2013-01-01

285

Understanding Boston  

NSDL National Science Digital Library

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

286

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

ERIC Educational Resources Information Center

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

Davson-Galle, Peter

2004-01-01

287

Combined magnetic-dipole and electric-quadrupole hyperfine interactions in rare-earth orthoferrite ceramics  

NASA Astrophysics Data System (ADS)

Perturbed-angular-correlation (PAC) spectroscopy was used to measure combined nuclear-magnetic-dipole and nuclear-electric-quadrupole interactions in rare-earth orthoferrite (REO) ceramics, RFeO3 (R=La,Pr,Nd,...,Lu). The rare-earth orthoferrites are canted antiferromagnets that have orthorhombically distorted perovskite structures. With the 111-->111Cd probe, the PAC measurements were made over a temperature range from laboratory temperature through the antiferromagnetic-to-paramagnetic transitions (740-620 K) and at or near 800 K. In the heavier REO's, the 111-->111Cd probe substitutes primarily into the rare-earth sites; and in the lighter REO's, it can substitute into both the Fe and the rare-earth sites. At the rare-earth sites, the probe undergoes a high-frequency electric-quadrupole interaction that is shifted in energy by a weak magnetic-dipole interaction. The direction of the associated magnetic hyperfine field is nearly perpendicular to the principal z axis of the electric-field-gradient (EFG) tensor. The magnitude of this field is small, and it may be produced by transferred spin density. In the heavier REO's, the rare-earth-site EFG's are nearly axially symmetric; and, as the rare-earth atomic number decreases, the EFG asymmetry increases. At the Fe sites, the probe undergoes a strong magnetic-dipole interaction that is shifted in energy by a low-frequency electric-quadrupole interaction, which involves very asymmetric EFG's. For PrFeO3, as an example, the strong magnetic-dipole interactions could be attributed to the presence of a supertransferred hyperfine field in which spin density is transferred via Fe-O-111Cd bonds. The predictions of a quantum-chemistry theory agree within a factor of 2 with the magnitude of this field. The direction of this field makes an angle of approximately 40° with the principal z axis of the EFG. For NdFeO3, similar results were obtained. The results of these experiments indicate that combined interactions can be measured in highly distorted crystals and that they can be analyzed. Moreover, these results indicate that PAC spectroscopy can provide new information about the magnitudes and directions of supertransferred hyperfine fields, which can be used as benchmarks for theoretical calculations.

Rearick, Todd M.; Catchen, Gary L.; Adams, James M.

1993-07-01

288

Nuclear Energy Level Argument for a Spheroidal Nuclear Model  

Microsoft Academic Search

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

James Rainwater

1950-01-01

289

Theory of nuclear magnetic relaxation  

NASA Technical Reports Server (NTRS)

A theory of nuclear magnetic interaction is based on the study of the stochastic rotation operator. The theory is applied explicitly to relaxation by anisotropic chemical shift and to spin-rotational interactions. It is applicable also to dipole-dipole and quadrupole interactions.

Mcconnell, J.

1983-01-01

290

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

291

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

292

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

293

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

294

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

295

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

296

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

297

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

298

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

299

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

300

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

301

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

SciTech Connect

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

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

2005-05-01

302

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

303

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

304

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

305

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

306

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

307

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

308

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

309

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

310

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

311

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

312

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

313

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

314

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

315

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

316

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

317

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

318

Understanding Condensation  

NSDL National Science Digital Library

Monica Hartman, Assistant Director for Science in St. Clair County, Michigan, conducted this research while she was the learning specialist in a small suburban district just outside a large Midwestern city. While teaching full time in this district she was also completing her doctoral program in education at the University of Michigan. In this chapter, she tells the story of a "science talk" about condensation among fifth graders. She acted as a source and facilitator of change as she and the fifth-grade teacher worked collaboratively to help students share responsibility for their own learning. She describes their continual assessment of student understanding that occurred as their students struggled to explain observations and as they, the teachers, carefully resisted the temptation to end the struggle by saying "that's right!"

Hartman, Monica

2007-12-01

319

Aiding understanding  

NASA Astrophysics Data System (ADS)

Research projects carried out by individual researchers or research teams which communicate the challenge and excitement of their work to a wider public are eligible for entry into the 1999 `Partnerships for Public Understanding' awards scheme. This is organized by the Engineering and Physical Sciences Research Council and follows on the success of a pilot scheme launched in 1998 which made 25 grants across the UK. Grant holders are invited to apply for awards to support them in high quality communication projects for the general public, with individual awards normally in the range of £10-20k, but higher awards may be made for exceptional projects. This year a special `Year 2000' PPU sum will be available for a proposal which will contribute significantly to public awareness of the likely impact on society of an aspect of science or engineering research during the first half of the new millennium. The awards have been introduced to support the EPSRC's aim of contributing to public awareness of leading edge research; highly innovative projects will be welcomed, as well as the by now more common activities such as interactive exhibits, public lectures, demonstrations and open days. Applicants should be current holders of EPSRC research grants or fellowships, or those who have held these since 1 April 1994. Proposals will be assessed by EPSRC with advice from communications and education specialists, and the closing date for entries is 1 September 1999. Successful bids will be announced towards the end of the year. Further information on the awards can be obtained from Geoffrey Moore at EPSRC (tel: 01793 444241, e-mail: geoffrey.moore@epsrc.ac.uk), whilst details of the call for proposals can be found on the website at www.epsrc.ac.uk (see pages `Support for public understanding').

1999-07-01

320

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

321

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

322

ESEEM of Orientationally Disordered Systems (II). Lineshape Singularities in S = {1}/{2}, I = 1 Systems with Small Quadrupole Interaction  

NASA Astrophysics Data System (ADS)

The electron spin-echo envelope-modulation (ESEEM) spectra of S = {1}/{2}, I = 1 systems with small quadrupole interaction (for instance, deuterium nuclei 2D) are analyzed for orientationally disordered systems. It is shown that the commonly accepted description of deuterium ESEEM spectra using theory developed for the S = {1}/{2}, I = {1}/{2} case is valid only in the limit of small hyperfine (HFI) and nuclear quadrupole interactions (NQI) relative to the nuclear Zeeman interaction. For larger HFI, apart from the "simple" basic (? ? and ? ?) and combination (? ? ± ? ?) features, the "higher" basic (2? ? and 2? ?) and combination [2? ?(?) ± ? ?(?), 2? ? ± 2? ?] harmonics appear in the spectra for I = 1. Analytical expressions are derived that define the positions of the higher combination harmonics. The presence of small NQI will complicate the basic and combination lineshapes, giving rise to line broadenings and/or to observable line splittings. These, in turn, can be interpreted in terms of the relative angle between the principal axes of the HFI and NQI tenser. The approach developed is demonstrated on the example of silver atoms stabilized in ?-irradiated AgNO 3/D 2O matrices.

Tyryshkin, A. M.; Dikanov, S. A.; Reijerse, E. J.

323

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

324

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

325

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

326

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

327

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

328

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

329

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

330

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

331

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

332

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

333

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

334

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

335

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

336

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

337

Mechanism of nuclear dissipation in fission and heavy-ion reactions  

SciTech Connect

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

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

1986-01-01

338

Understanding solution-state noncovalent interactions between xenobiotics and natural organic matter using 19F/1H heteronuclear saturation transfer difference nuclear magnetic resonance spectroscopy.  

PubMed

A combination of forward and reverse heteronuclear ((19)F/(1)H) saturation transfer difference (STD) nuclear magnetic resonance (NMR) spectroscopic techniques were applied to characterize the noncovalent interactions between perfluorinated aromatic xenobiotics and dissolved humic acid. These NMR techniques produce detailed molecular-level descriptions of weak noncovalent associations between components in complex environmental mixtures, allowing the mechanisms underlying these interactions to be explored; (19)F observed heteronuclear STD (H-STD) is used to describe the average molecular orientation of the xenobiotics during their interactions with humic acid, whereas (1)H observed reverse-heteronuclear STD (RH-STD) is used to both identify and quantify preferences exhibited by xenobiotics for interactions at different types of humic acid moieties. First, by using H-STD, it is shown that selected aromatic organofluorides orient with their nonfluorine functional groups (OH, NH(2), and COOH) directed away from humic acid during the interactions, suggesting that these functional groups are not specifically involved. Second, the RH-STD experiment is shown to be sensitive to subtle differences in preferred interaction sites in humic acid and is used here to demonstrate preferential interactions at aromatic humic acid sites for selected aromatic xenobiotics, C(10)F(7)OH, and C(6)F(4)X(2), (where X?=?F, OH, NH(2), NO(2), or COOH), that can be predicted from the electrostatic potential density maps of the xenobiotic. PMID:21538490

Longstaffe, James G; Simpson, André J

2011-08-01

339

Friction in nuclear dynamics  

SciTech Connect

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

Swiatecki, W.J.

1985-03-01

340

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

341

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

342

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

343

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

344

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 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.

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

2014-05-01

345

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

346

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?-=(0.96±0.02)×10-2efm2 [GE2(0)=0.680±0.012].

Ramalho, G.; Peña, M. T.

2011-03-01

347

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

348

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

349

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

350

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

351

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

352

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

353

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

354

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...

355

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

356

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

357

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

358

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

359

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

360

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

361

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

362

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

363

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

364

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

365

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

366

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

367

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

368

Investigation of a quadrupole ultra-high vacuum ion pump  

NASA Technical Reports Server (NTRS)

The new nonmagnetic ion pump resembles the quadrupole ionization gage. The dimensions are larger, and hyperbolically shaped electrodes replace the four rods. Their surfaces follow y sq. = 36 + x sq. (x, y in centimeters). The electrodes, 55 cm long, are positioned lengthwise in a tube. At one end a cathode emits electrons; at the other end a narrowly wound flat spiral of tungsten clad with titanium on cathode potential can be heated for titanium evaporation. Electrons accelerated by a dc potential of the surface electrodes oscillate between the ends on rotational trajectories, if a high frequency potential superimposed on the dc potential is properly adjusted. Pumping speeds (4-100 liter/sec) for different gases at different peak voltages (1000-3000V) at corresponding frequencies (57-100 MHz), and at different pressures 0.00001 to the minus 9 power Torr were observed. The lowest pressure reached was below 10 to the minus 10 power Torr.

Schwarz, H. J.

1974-01-01

369

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

370

Statistics of electric-quadrupole lines in atomic spectra  

NASA Astrophysics Data System (ADS)

In hot plasmas, a temperature of a few tens of eV is sufficient for producing highly stripped ions where multipole transitions become important. At low density, the transitions from tightly bound inner shells lead to electric-quadrupole (E2) lines which are comparable in strength with electric-dipole ones. In this work, we propose analytical formulas for the estimation of the number of E2 lines in a transition array. Such expressions rely on statistical descriptions of electron states and J-levels. A generalized ‘J-file’ sum rule for E2 lines and the strength-weighted shift and variance of the line energies of a transition array n?N + 1 ? n?Nn??? of inter-configuration E2 lines are also presented.

Pain, Jean-Christophe; Gilleron, Franck; Bauche, Jacques; Bauche-Arnoult, Claire

2012-07-01

371

Uranus' (3-0) H2 quadrupole line profiles  

NASA Technical Reports Server (NTRS)

Spectra of Uranus' S3(0) and S3(1) H2 quadrupole lines, obtained during the 1978-1980 apparitions, are analyzed, and are found to require the presence of a deep cloud. Modifications of the Baines and Bergstralh (1986) standard model, including an additional haze layer above the 16-km-am H2 level which contains strongly absorbing particles, are needed to fit the observations. For a Rayleigh phase function, such a haze (uniformly mixed with the gas above this level) would have an absorption optical depth of 0.16 and a single scattering particle albedo of 0.30. This modification would imply a fraction of normal H2 equal to 0.25 + or - 0.10, in agreement with the Baines and Bergstralh standard model.

Trafton, L.

1987-01-01

372

Plasma-beam traps and radiofrequency quadrupole beam coolers.  

PubMed

Two linear trap devices for particle beam manipulation (including emittance reduction, cooling, control of instabilities, dust dynamics, and non-neutral plasmas) are here presented, namely, a radiofrequency quadrupole (RFQ) beam cooler and a compact Penning trap with a dust injector. Both beam dynamics studies by means of dedicated codes including the interaction of the ions with a buffer gas (up to 3 Pa pressure), and the electromagnetic design of the RFQ beam cooler are reported. The compact multipurpose Penning trap is aimed to the study of multispecies charged particle samples, primarily electron beams interacting with a background gas and/or a micrometric dust contaminant. Using a 0.9 T solenoid and an electrode stack where both static and RF electric fields can be applied, both beam transport and confinement operations will be available. The design of the apparatus is presented. PMID:24593614

Maggiore, M; Cavenago, M; Comunian, M; Chirulotto, F; Galatà, A; De Lazzari, M; Porcellato, A M; Roncolato, C; Stark, S; Caruso, A; Longhitano, A; Cavaliere, F; Maero, G; Paroli, B; Pozzoli, R; Romé, M

2014-02-01

373

Alternative Mechanical Structure for LARP Nb3Sn Quadrupoles  

SciTech Connect

An alternative structure for the 120 mm Nb{sub 3}Sn quadrupole magnet presently under development for use in the upgrade for LHC at CERN is presented. The goals of this structure are to build on the existing technology developed in LARP with the LQ and HQ series magnets and to further optimize the features required for operation in the accelerator. These features include mechanical alignment needed for field quality and provisions for cold mass cooling with 1.9 K helium in a helium pressure vessel. The structure will also optimize coil azimuthal and axial pre-load for high gradient operation, and will incorporate features intended to improve manufacturability, thereby improving reliability and reducing cost.

Anerella, M.; Cozzolino, J.; Ambrosio, G.; Caspi, S.; Felice, H.; Kovach, P.; Lamm, M.; Sabbi, G.; Schmalzle, J.; Wanderer, P.

2010-08-01

374

Quadrupole-octupole coupled states in {sup 112}Cd  

SciTech Connect

The properties of negative-parity states in the 2.5 MeV region in {sup 112}Cd have been investigated with the (n,n{sup {prime}}{gamma}) reaction. For many of these levels, lifetimes have been measured, and B(E1) and B(E2) values for their decays have been determined. Several transitions exhibit enhanced B(E2) values for decay to the 3{sub 1}{sup {minus}} octupole state, indicative of quadrupole-octupole coupled (2{sup +}{circle_times}3{sup {minus}}) states. The B(E1) values observed are typically in the range of 1{endash}5{times}10{sup {minus}4} Weisskopf units (W.u.), irrespective of the final state. {copyright} {ital 1999} {ital The American Physical Society}

Garrett, P.E.; McGrath, C.A.; Yeh, M.; Yates, S.W. [University of Kentucky, Lexington, Kentucky 40506-0055 (United States)] [University of Kentucky, Lexington, Kentucky 40506-0055 (United States); Garrett, P.E. [Lawrence Livermore National Laboratory, L-414, P.O. Box 808, Livermore, California 94550 (United States)] [Lawrence Livermore National Laboratory, L-414, P.O. Box 808, Livermore, California 94550 (United States); Lehmann, H.; Jolie, J. [Institut de Physique, Universite de Fribourg, Perolles, CH-1700 Fribourg (Switzerland)] [Institut de Physique, Universite de Fribourg, Perolles, CH-1700 Fribourg (Switzerland)

1999-05-01

375

Restoring the skew quadrupole moment in the Tevatron dipoles  

SciTech Connect

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

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

2005-05-01

376

Nb3Sn Quadrupole Magnets for the LHC IR  

SciTech Connect

The development of insertion quadrupoles with 205 T/m gradient and 90 mm bore represents a promising strategy to achieve the ultimate luminosity goal of 2.5 x 10{sup 34} cm{sup -2}s{sup -1} at the Large Hadron Collider (LHC). At present, Nb{sub 3}Sn is the only practical conductor which can meet these requirements. Since Nb{sub 3}Sn is brittle, and considerably more strain sensitive than NbTi, the design concepts and fabrication techniques developed for NbTi magnets need to be modified appropriately. In addition, IR magnets must provide high field quality and operate reliably under severe radiation loads. The results of conceptual design studies addressing these issues are presented.

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

2001-08-01

377

Nuclear astrophysics  

SciTech Connect

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

Haxton, W.C.

1992-01-01

378

Nuclear astrophysics  

SciTech Connect

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

Haxton, W.C.

1992-12-31

379

Nuclear moments in covariant density functional theory  

NASA Astrophysics Data System (ADS)

Recent progresses on microscopic and self-consistent description of the nuclear moments in covariant density functional theory based on a point-coupling interaction are briefly reviewed. In particular, the electric quadrupole moments of Cd isotopes and the magnetic moments of Pb isotopes are discussed.

Meng, J.; Zhao, P. W.; Zhang, S. Q.; Hu, J. N.; Li, J.

2014-05-01

380

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; Bahçeli, S; Klinowski, J

2000-07-01

381

Field Quality Study of the LARP Nb3Sn 3.7m-Long Quadrupole Models of LQ Series  

SciTech Connect

After the successful test of the first long Nb{sub 3}Sn quadrupole magnet (LQS01), the US LHC Accelerator Research Program (LARP) has assembled and tested a new 3.7 m-long Nb{sub 3}Sn quadrupole (LQS02). This magnet has four new coils made of the same conductor as LQS01 coils, and it is using the same support structure. LQS02 was tested at the Fermilab Vertical Magnet Test Facility with the main goal to confirm that the long models can achieve field gradient above 200 T/m, LARP target for 90-mm aperture, as well as to measure the field quality. These long models lack some alignment features and it is important to study the field harmonics. Previous field quality measurements of LQS01 showed higher than expected differences between measured and calculated harmonics compared to the short models (TQS) assembled in a similar structure. These differences could be explained by the use of two different impregnation fixtures during coil fabrication. In this paper, we present a comparison of the field quality measurements between LQS01 and LQS02 as well as a comparison with the short TQS models. If the result supports the coil fabrication hypothesis, another LQS assembly with all coils fabricated in the same fixture will be produced for understanding the cause of the discrepancy between short and long models.

AMbrosio, G.; Andreev, N.; Bossert, R.; Chlachidze, G.; DiMarco, J.; Kashikhin, V.V.; Lamm, M.J.; Nobrega, F.; Prebys, E.; Sylvester, C.; Tartaglia, M.; /Fermilab /LBL, Berkeley /Brookhaven

2011-09-01

382

Shell model calculations of B (E2) values, static quadrupole moments, and g factors for a number of N =Z nuclei  

NASA Astrophysics Data System (ADS)

In this work we look at the low-lying nuclear structure properties of several N =Z nuclei residing between the doubly magic nuclei 40Ca and 100Sn. Using large shell model codes, we calculate and discuss the systematics of energies. We show energy levels, B (E2)'s, static quadrupole moments, and g factors of these N =Z nuclei. In all cases, we compare the results of two different interactions which yield significantly different occupation numbers. We compare our shell model results with those of the rotational and vibrational models. By examining B (E2)'s and static quadrupole moments, we make associations with collective models and find that in the model space considered here, 88Ru is oblate. The quadrupole moment of the lowest 2+state of 92Pd is calculated to be very small. This would appear to support a vibrational picture and indeed recent measurements give equally spaced levels up to J =6+ but the authors also point out that the B (E2)'s do not steadily increase as is required by such a model.

Robinson, S. J. Q.; Hoang, T.; Zamick, L.; Escuderos, A.; Sharon, Y. Y.

2014-01-01

383

[Fragmentation pathways of five estrogens using electrospray ionization quadrupole time-of-flight mass spectrometry].  

PubMed

The fragmentation pathways of five estrogens (estradiol, estrone, equilin sulfate, 17 a-dihydroequilin sulfate and equilenin sulfate) have been studied with high resolution and high mass accuracy using electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-Q-TOF/MS) in the negative ion mode. Molecular weights were obtained from [M-H](-) ions in the product ion spectra. The results indicate that the five structurally similar estrogens have similar fragmentation pathways. Using their stable isotope forms as internal reference compounds, the accurate mass and composition of the fragment ions were determined. During collision-induced dissociation (CID), cleavage is initiated by loss of oxygen atoms from carbon-17, after which D and C rings cleave sequentially and rearrange to finally form stable conjugate structures with highly abundant characteristic fragment ions at m/z 183 (accompanied by m/z 181), m/z 169 and m/z 145 (accompanied by m/z 143). Understanding these characteristic fragmentation pathways of estrogens will be helpful in identifying the structures of steroid hormones in general. PMID:24974469

Zhang, Ting-Lan; Shi, Mei-Yun; Di, Xin; Gu, Jing-Kai

2014-04-01

384

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

385

Nb3Sn quadrupoles in the LHC IR Phase I upgrade  

SciTech Connect

After a number of years of operation at nominal parameters, the LHC will be upgraded to a higher luminosity. This paper discusses the possibility of using a limited number of Nb{sub 3}Sn quadrupoles for hybrid optics layouts for the LHC Phase I luminosity upgrades with both NbTi and Nb{sub 3}Sn quadrupoles. Magnet parameters and issues related to using Nb{sub 3}Sn quadrupoles including aperture, gradient, magnetic length, field quality, operation margin, et cetera are discussed.

Zlobin, A.V.; Johnstone, J.A.; Kashikhin, V.V.; Mokhov, N.V.; Rakhno, I.L.; /Fermilab; de Maria, R.; Peggs, S.; Robert-Demolaize, G.; Wanderer, P.; /Brookhaven

2008-06-01

386

Nb3Sn Quadrupoles in the LHC IR Phase I Upgrade  

SciTech Connect

After a number of years of operation at nominal parameters, the LHC will be upgraded for higher luminosity. This paper discusses the possibility of using a limited number of Nb{sub 3}Sn quadrupoles for hybrid optics layouts for the LHC Phase I luminosity upgrades with both NbTi and Nb{sub 3}Sn quadrupoles. Magnet parameters and issues related to using Nb{sub 3}Sn quadrupoles including aperture, gradient, magnetic length, field quality, operation margin, et cetera are discussed.

Zlobin,A.; Johnstone, J.; Kashikhin, V.; Mokhov, N.; Rakhno, I.; deMaria, R.; Peggs, S.; Robert-Demolaize, F.; Wanderer, P.

2008-06-23

387

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

388

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

SciTech Connect

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

Morrison, M.E.; Behrsing, G.U.; Fulton, R.L. [Lawrence Berkeley Lab., CA (United States)] [Lawrence Berkeley Lab., CA (United States)

1994-07-01

389

Optimal non-linear, orthomorphic, magnetic quadrupole lens systems for ion microprobes  

NASA Astrophysics Data System (ADS)

The lens strengths, demagnifications and spherical aberrations of many different quadrupole focusing systems for an ion microprobe are calculated and compared. The paper studies triplet and Russian quadruplet combinations of magnetic quadrupoles which give equal (in magnitude) demagnification in the two planes of focusing. The matrizant (or the transfer matrix) of the third order is determined for different geometries of the studied systems. Numerical optimization of the quadrupole systems is applied. The above matrizant for given geometries is used and the size of the object (first) and aperture (second) diaphragms is varied to obtain the minimum spot size at the specimen for a given beam emittance. The optimal systems are discussed.

Dymnikov, A. D.; Jamieson, D. N.; Legge, G. J. F.

1995-09-01

390

Multi-spectral plasmon induced transparency via in-plane dipole and dual-quadrupole coupling.  

PubMed

We experimentally demonstrated an approach based on dipole and dual-quadrupole coupling to construct a planar metamaterial supporting multi-spectral plasmon induced transparency. The structure consists of two short silver wires (dipole) and two long silver wires (dual-quadrupole). The in-plane coupling between the dipole and the dual-quadrupole leads to two transmission windows even in the absorbance linewidth of the dipole. This phenomenon is well described and understood by numerical analyses and a classical oscillator model. PMID:24921261

Miyata, Masashi; Hirohata, Jumpei; Nagasaki, Yusuke; Takahara, Junichi

2014-05-19

391

Low temperature quench performance of Fermilab Low-{Beta} insertion quadrupoles  

SciTech Connect

The recently revived superconducting magnet program at Fermilab is currently focused on the development of high gradient quadrupoles for possible use in the Large Hadron Collider (LHC) interaction regions at CERN. In order to provide input for the new quadrupole design which will operate in superfluid helium, we have tested a Fermilab Tevatron low-{beta} quadrupole cold mass and compared its low temperature performance to a newly assembled heavily instrumented version which was mechanically modified to take advantage of the gain in critical current.

Bossert, R.; Lietzke, A. [Lawrence Berkeley National Lab., CA (United States); McInturff, A.D. [Lawrence Berkeley National Lab., CA (United States); Scanlan, R. [Lawrence Berkeley National Lab., CA (United States); LHC Collaboration

1997-04-01

392

Study of electric quadrupole interactions at 111Cd on Zn sites in RZn (R = Ce, Gd, Tb, Dy) compounds using the PAC spectroscopy  

NASA Astrophysics Data System (ADS)

Nuclear quadrupole interactions at Zn sites in the intermetallic compounds RZn (R = Ce, Gd, Tb, Dy) have been investigated by perturbed gamma-gamma angular correlation (PAC) spectroscopy using 111In(111Cd) as probe nuclei. Measurements were carried out in the temperature range of 10-295 K. These compounds exhibit CsCl type cubic structure and while CeZn shows antiferromagnetic behaviour, the compounds GdZn, TbZn, DyZn are ferromagnetic. The results show that the EFG in these compounds is sensitive to the distribution of rare-earth 4f-electron charges.

Bosch-Santos, Brianna; Carbonari, Artur W.; Cabrera-Pasca, Gabriel A.; Costa, Messias S.; Saxena, Rajendra N.

2013-05-01

393

Investigation of hyperfine quadrupole interactions in UGe2 and UAl2 compounds on 111Cd probe nuclei by the perturbed angular correlation method  

NASA Astrophysics Data System (ADS)

The parameters of nuclear quadrupole hyperfine interaction in intermetallic UGe2 and UAl2 compounds have been measured in a temperature range of 100-300 K using the perturbed angular ?? correlation method on 111Cd probe nuclei. The results obtained for UGe2 indicate a pronounced anisotropic character in the distribution of f electrons in agreement with the calculation of the electronic structure of this compound. The hybridization degree between f electrons of U and p electrons of Al in UAl2 is lower than the hybridization degree between f electrons of U and p electrons of Ge in UGe2.

Tsvyashchenko, A. V.; Fomicheva, L. N.; Salamatin, A. V.; Velichkov, A. I.; Kochetov, O. I.; Ryasny, G. K.; Sorokin, A. A.; Budzynski, M.

2009-05-01

394

The First Reactor, Understanding the Atom Series.  

ERIC Educational Resources Information Center

This booklet is one of the "Understanding the Atom" Series. Consisting of three sections, it is an account of the development of the first nuclear reactor by a team of scientists led by Enrico Farmi. The first section briefly reviews the early work on nuclear fission and neutron emission, the impact of Einstein's letter to President Roosevelt, the…

Allardice, Corbin; And Others

395

Understanding the TMI2 accident: an overview  

Microsoft Academic Search

The accident at Three Mile Island Unit 2 (TMI-2) on March 28, 1979 has had a profound impact on the nuclear power industry despite the fact that the health consequences to the public were insignificant. There is considerable benefit to the nuclear power industry in understanding the progression of this severe core damage accident and its relationship to the very

R. R. Hobbins; J. M. Broughton; C. M. Allison

1986-01-01

396

Corrector/quadrupole/sextupole power leads for the Relativistic Heavy Ion Collider at Brookhaven National Laboratory.  

National Technical Information Service (NTIS)

In RHIC (Relativistic Heavy Ion Collider), there are 492 CQS (Corrector/Quadrupole/Sextupole) assemblies which require leads to carry the current from the power supply to the magnet. The lead assemblies will contain these leads along with instrumentation ...

R. Shutt K. Hornik M. Rehak

1993-01-01

397

Research Relative to an Advanced Rod Control System for Quadrupole Mass Spectrometry Applications.  

National Technical Information Service (NTIS)

The design of a suitable amplifier output stage using available transistors and passive components is summarized. All of the analysis and calculation confirm that it is feasible to design the amplifier and quadrupole coupling circuit needed for the Advanc...

G. R. Carignan

1987-01-01

398

Rotational and magnetic shunt permanent magnet quadrupoles with variable magnetic strength  

SciTech Connect

Next Linear Collider (NLC) and Very Large Hadron Collider (VLHC) projects suppose to use permanent magnets as bending, focusing and correcting elements. Prototypes of two permanent magnet quadrupoles with variable strength were built and successfully tested in Fermilab. Quadrupoles have 12.7 mm aperture diameter, 100 T/m gradient with an adjustment range of 0 to -20%. Special designs provide high precision magnetic center stability during strength change. SmCo5 permanent magnet bricks were used in these prototypes. Rotational quadrupole consists of four sections. Two central sections are rotated in counter directions to adjust the strength. Magnetic shunt quadrupole design provides variable shunting of the magnetic flux. The numerical simulation, designs, measuring results are described.

Vladimir Kashikhin et al.

2002-03-28

399

Measurement of the quadrupole moment of the /sup 112/Sn(6/sup +/) isomer  

SciTech Connect

The quadrupole coupling constant of the /sup 112/Sn(6/sup +/) isomer in the hexagonal Cd host is measured by using the time-differential perturbed angular distribution (TDPAD) method. Values of the quadrupole coupling constants e/sup 2/qQ/h = 66.25 +- 4.00 MHz and 57.56 +- 6.90 MHz are found at 290/sup 0/ and 500/sup 0/, respectively. The quadrupole moment of the 6/sup +/ state in /sup 112/Sn is derived in terms of the electric field gradient for Sn in Cd given by Herrlander. The deduced quadrupole moment Q is 0.29 +- 0.07b. The simple shell model estimate shows that the /sup 112/Sn(6/sup +/) state is possibly a mixed configuration of ( g/sup 6//sub 7/2/)6/sup +/ and ( g/sup 7//sub 7/2/xd/sup 5//sub 5/2/)6/sup +/.

ZHU Shengyun; DONG Mingli; SHEN Weiqi

1985-04-01

400

Stability Regimes in a Helical Quadrupole Focusing Accelerator - Theory and Simulation.  

National Technical Information Service (NTIS)

The inclusion of helical quadrupole (stellarator) and axial guide fields in high current spiral line or recirculating accelerator configurations provides a high tolerance to energy mismatch and confines the beam against space charge forces. In such a conf...

C. M. Tang G. Joyce J. Krall P. Sprangle

1990-01-01

401

Design and operation of a laminar-flow electrostatic-quadrupole-focused acceleration column  

SciTech Connect

This report deals with the design principles involved in the design of a laminar-flow electrostatic-quadrupole-focused acceleration column. In particular, attention will be paid to making the parameters suitable for incorporation into a DC MEQALAC design.

Maschke, A.W.

1983-06-20

402

Kinetic equilibrium of space charge dominated beams in a misaligned quadrupole focusing channel  

NASA Astrophysics Data System (ADS)

The dynamics of intense beam propagation through the misaligned quadrupole focusing channel has been studied in a self-consistent manner using nonlinear Vlasov-Maxwell equations. The equations of motion of the beam centroid have been developed and found to be independent of any specific beam distribution. A Vlasov equilibrium distribution and beam envelope equations have been obtained, which provide us a theoretical tool to investigate the dynamics of intense beam propagating in a misaligned quadrupole focusing channel. It is shown that the displaced quadrupoles only cause the centroid of the beam to wander off axis. The beam envelope around the centroid obeys the familiar Kapchinskij-Vladimirskij envelope equation that is independent of the centroid motion. However, the rotation of the quadrupole about its optical axis affects the beam envelope and causes an increase in the projected emittances in the two transverse planes due to the inter-plane coupling.

Goswami, A.; Sing Babu, P.; Pandit, V. S.

2013-07-01

403

Kinetic equilibrium of space charge dominated beams in a misaligned quadrupole focusing channel  

SciTech Connect

The dynamics of intense beam propagation through the misaligned quadrupole focusing channel has been studied in a self-consistent manner using nonlinear Vlasov-Maxwell equations. The equations of motion of the beam centroid have been developed and found to be independent of any specific beam distribution. A Vlasov equilibrium distribution and beam envelope equations have been obtained, which provide us a theoretical tool to investigate the dynamics of intense beam propagating in a misaligned quadrupole focusing channel. It is shown that the displaced quadrupoles only cause the centroid of the beam to wander off axis. The beam envelope around the centroid obeys the familiar Kapchinskij-Vladimirskij envelope equation that is independent of the centroid motion. However, the rotation of the quadrupole about its optical axis affects the beam envelope and causes an increase in the projected emittances in the two transverse planes due to the inter-plane coupling.

Goswami, A.; Sing Babu, P.; Pandit, V. S. [Variable Energy Cyclotron Centre, 1/AF, Bidhannagar, Kolkata 700064 (India)] [Variable Energy Cyclotron Centre, 1/AF, Bidhannagar, Kolkata 700064 (India)

2013-07-15

404

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

SciTech Connect

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

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

2006-03-13

405

Field Quality Measurements and Analysis of the LARP Technology Quadrupole Models  

SciTech Connect

One of the US-LHC accelerator research program goals is to develop and prove the design and technology of Nb{sub 3}Sn quadrupoles for an upgrade of the LHC Interaction Region (IR) inner triplets. Four 1-m long technology quadrupole models with a 90 mm bore and field gradient of 200 T/m based on similar coils and different mechanical structures have been developed. In this paper, we present the field quality measurements of the first several models performed at room temperature as well as at superfluid helium temperature in a wide field range. The measured field harmonics are compared to the calculated ones. The field quality of Nb{sub 3}Sn quadrupole models is compared with the NbTi quadrupoles recently produced at Fermilab for the first generation LHC IRs.

Chlachidze, G.; DiMarco, J.; Kashikhin, V.V.; Lamm, M.; Schlabach, P.; Tartaglia, M.; Tompkins, J.C.; Velev, G.V.; Zlobin, A.V.; Caspi, S.; Ferracin, P.; Sabbi, G.I.; Bossert, R.

2008-06-01

406

Field quality measurements and abalysis of the LARP technology quadrupole models  

SciTech Connect

One of the US-LHC accelerator research program goals is to develop and prove the design and technology of Nb{sub 3}Sn quadrupoles for an upgrade of the LHC Interaction Region (IR) inner triplets. Four 1-m long technology quadrupole models with a 90 mm bore and field gradient of 200 T/m based on similar coils and different mechanical structures have been developed. In this paper, we present the field quality measurements of the first several models performed at room temperature as well as at superfluid helium temperature in a wide field range. The measured field harmonics are compared to the calculated ones. The field quality of Nb{sub 3}Sn quadrupole models is compared with the NbTi quadrupoles recently produced at Fermilab for the first generation LHC IRs.

Bossert, R.; Chlachidze, G.; DiMarco, J.; Kashikhin, V.V.; Lamm, M.; Schlabach, P.; Tartaglia, M.; Tompkins, J.C.; Velev, G.V.; Zlobin, A.V.; Caspi, S.; /Fermilab /LBL, Berkeley

2007-08-01

407

Hybrid permanent magnet quadrupoles for the Recycler Ring at Fermilab  

SciTech Connect

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 mm thick strontium ferrite supply the flux to the back of the pole to produce the desired gradients (0.6 to 2.75 T/m). For temperature compensation, Ni-Fe alloy strips are interspersed between ferrite bricks to subtract flux in a temperature dependent fashion. Adjustments of the permeance of each pole using iron between the pole and the flux return shell permits the matching of pole potentials. Magnetic potentials of the poles are adjusted to the desired value to achieve the prescribed strength and field uniformity based on rotating coil harmonic measurements. Procurement, fabrication, pole potential adjustment, and measured fields will be reported.

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

1997-10-01

408

Wideband measurement of shear induced birefringence by quadrupole method  

NASA Astrophysics Data System (ADS)

We developed a new method for the measurement of the dynamic birefringence induced by the alternating shear deformation in fluid samples. A quadrupole piezoactuator generates the pure shear deformation in the frequency range from 1 Hz to 5 kHz and causes the molecular orientation, or the anisotropic conformation of polymers and molecular associations, which is observed by the optical ellipsometry technique. The spectrum of the shear-induced birefringence observed for the isotropic phase of the liquid crystal p-n-hexyl p'-cyanobiphenyl (6CB) shows linear dependence on the frequency up to 5 kHz, corroborating the effective band of the experimental system. The sensitivity of the system was demonstrated by the quantitative measurement of the birefringence for the isotropic phase of p-n-pentyl p'-cyanobiphenyl (5CB). The system was also applied to the aqueous solution of the worm such as micelles and the result shows the relaxation of shear induced birefringence at around 10 Hz, which agrees well with the previous reports.

Hosoda, M.; Horii, K.; Nomura, H.; Sakai, K.

2006-05-01

409

Development of a quadrupole ion trap mass spectrometer  

NASA Astrophysics Data System (ADS)

Because of its potential to be made portable the quadrupole ion trap (QPIT) is a prime candidate for specialized applications such as atmospheric studies, other field measurements, or measurements anywhere a laboratory instrument would be prohibitively inconvenient. To utilize the QPIT in such ways it is necessary to design and construct custom built instruments. A QPIT mass spectrometer was constructed as the foundation for such future development. Two ionization schemes were employed. Direct electron bombardment was used for in situ ion production, and UV photoionization was used to produce ions external to the trap. Calibration measurements determined that the system performed as theory dictated. It was also demonstrated that the system was capable of sampling the atmosphere and detecting the presence of an atmospheric contaminant. Finally, DC bias foils were invented as a novel approach to mass isolation in the trap. The use of DC bias foils was demonstrated to be an exceptionally easy and inexpensive method of controlling the contents of the QPIT.

Hebert, Joseph Ellis

410

Radio-frequency quadrupole vane-tip geometries  

SciTech Connect

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 vane tips. The choice of the best vane-tip geometry depends on considerations such as the peak surface electric field, per cent of higher multipole components, and ease of machining. We review the vane-tip geometry based on the ideal two-term potential function and briefly describe a method for calculating the electric field components in an RFQ cell with arbitrary vane-tip geometry. We describe five basic geometries and use the prototype RFQ design for the Fusion Materials Irradiation Test (FMIT) accelerator as an example to compare the characteristics of the various geometries.

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

1983-01-01

411

Quadrupole deformed and octupole collective bands in 228Ra  

NASA Astrophysics Data System (ADS)

Spins and parities for collective states in 228Ra have been determined from conversion electron measurements with a mini-orange ? spectrometer. The fast-timing ???( t) method has been used to measure lifetimes of T {1}/{2} = 550(20) ps and 181 (3) ps for the 2 1+ and 4 1+ aembers of the K = 0 + band, and T {1}/{2} ? 7 ps and ?6 ps for the 1 1- and 3 1- members of the K = 0 - band, respectively The quadrupole moments, Q0 deduced from the B (E2; 2 1+ ? 0 1+) and B (E2; 4 1+ ? 2 1+) rates are in good agreement with the previously measured value and the systematics of the region. However, the B(E1) rates of ?4 × 10 -4 e 2 fm 2, which represent the first B(E1) measurements for this nucleus, are at least 25 times larger than the value previously suggested for 228Ra. The new results are consistent with the B(E1) rates recently measured for the neighbouring 227Ra and reveal octupole correlations in 228Ra.

Gulda, K.; Mach, H.; Aas, A. J.; Borge, M. J. G.; Burke, D. G.; Fogelberg, B.; Gietz, H.; Grant, I. S.; Hagebo, E.; Hill, P.; Hoff, P.; Kaffrell, N.; Kurcewicz, W.; Lindroth, A.; Løvhøiden, G.; Martinez, T.; Mattsson, S.; Naumann, R. A.; Nybø, K.; Nyman, G.; Rubio, B.; Sanchez-Vega, M.; Tain, J. L.; Taylor, R. B. E.; Tengblad, O.; Thorsteinsen, T. F.; Isolde Collaboration

412

Quadrupole mass filter operation under the influence of magnetic field.  

PubMed

This work demonstrates resolution enhancement of a quadrupole mass filter (QMF) under the influence of a static magnetic field. Generally, QMF resolution can be improved by increasing the number of rf cycles an ion experiences when passing through the mass filter. In order to improve the resolution, the dimensions of the QMF or the operating parameters need to be changed. However, geometric modifications to improve performance increase the manufacturing cost and usually the size of the instrument. By applying a magnetic field, a low-cost, small footprint instrument with reduced power requirements can be realized. Significant improvement in QMF resolution was observed experimentally for certain magnetic field conditions, and these have been explained in terms of our theoretical model developed at the University of Liverpool. This model is capable of accurate simulation of spectra allowing the user to specify different values of mass spectrometer dimensions and applied input signals. The model predicts enhanced instrument resolution R>26,000 for a CO2 and N2 mixture with a 200-mm long mass filter operating in stability zone 3 via application of an axial magnetic field. PMID:24338888

Syed, S U A H; Maher, S; Taylor, S

2013-12-01

413

Nuclear structure of {sup 231}Ra  

SciTech Connect

The study of the upper border of the octupole deformation region near A=225, where the octupole deformation vanishes in the presence of a well developed quadrupole field, is of great relevance in order to understand the interplay of octupole and quadrupole collectivities. Within the IS322 collaboration at CERN we carry out a systematic investigation of the heavy Fr-Th nuclei that presently includes {sup 227}Fr, {sup 227,228,229}Ra, {sup 229}Ac and {sup 229,231}Th. The heaviest Ra isotope we have studied so far and in which the fast timing {beta}{gamma}{gamma}(t) method has been applied is {sup 231}Ra.

Boutami, R.; Fraile, L. M.; Borge, M. J. G.; Lopez-Jimenez, M. J.; Teijeiro, A. G. [Instituto de Estructura de la Materia, CSIC, Serrano 113 bis, E-28006 Madrid (Spain); Aas, A. J.; Hageboe, E. [Department of Chemistry, Univ. of Oslo, P.O. Box 1033, Blindern, N-0315 Oslo (Norway); Fogelberg, B.; Mach, H. [Department of Neutron Research, Univ. of Uppsala, S-61182 Nykoeping (Sweden); Garcia-Raffi, L. M.; Martinez, T.; Rubio, B.; Tain, J. L. [Instituto de Fisica Corpuscular, CSIC-Univ. Valencia, E-46100 Burjassot (Spain); Grant, I. S. [Schuster Laboratory, Univ. of Manchester, Manchester M13 9PL (United Kingdom); Gulda, K.; Kurcewicz, W. [Department of Physics, Univ. of Warsaw, Pl-00 681 Warsaw (Poland); Loevhoeiden, G. [Department of Physics, Univ. of Oslo, P.O. Box 1048, Blindern, N-0316 Oslo (Norway); Tengblad, O. [Instituto de Estructura de la Materia, CSIC, Serrano 113 bis, E-28006 Madrid (Spain); EP Division, CERN, CH-1211 Geneva 23 (Switzerland); Thorsteinsen, T. F. [Department of Physics, Univ. of Bergen, N-5000 Bergen (Norway)

1999-11-16

414

Nuclear Structure of {sup 231}Ra  

SciTech Connect

The study of the upper border of the octupole deformation region near A=225, where the octupole deformation vanishes in the presence of a well developed quadrupole field, is of great relevance in order to understand the interplay of octupole and quadrupole collectivities. Within the IS322 collaboration at CERN we carry out a systematic investigation of the heavy Fr - Th nuclei that presently includes {sup 227}Fr, {sup 227,228,229}Ra, {sup 229}Ac and {sup 229,231}Th. The heaviest Ra isotope we have studied so far and in which the fast timing {beta}{gamma}{gamma}(t) method has been applied is {sup 231}Ra.

Boutami, R.; Fraile, L.M.; Borge, M.J.G.; Aas, A.J.; Fogelberg, B.; Garcia-Raffi, L.M.; Grant, I.S.; Gulda, K.; Hagebo, E.; Kurcewicz, W.; Lopez-Jimenez, M.J.; Lovhoiden, G.; Mach, H.; Martinez, T.; Rubio, B.; Tain, J.L.; Teijeiro, A.G.; Tengblad, O.; Thorsteinsen, T.F.

1999-12-31

415

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

416

A limitation of hysteresis in the correction of the sextupole field in a magnetic quadrupole lens  

NASA Astrophysics Data System (ADS)

Parasitic sextupole fields present in magnetic quadrupole lenses can be corrected by shunting the current flowing through one or two adjacent pole piece coils. It is shown here that this procedure can be limited by hysteresis in the quadrupole lens. This means that the sextupole field strength and also the size of the current shunts required to correct it depend on the direction of the current flow in the lens.

Breese, M. B. H.; Swietlicki, E.; Pallon, J.

1993-12-01

417

Design of an iron dominated quadrupole magnet with a high pole-tip flux density  

Microsoft Academic Search

Designing steel-dominated high-field quadrupoles one finds that saturation effects cause a considerable reduction in field quality, i.e., an increase in ?B(?, B0)\\/B0 = [By(real)(B0, ?) y(ideal)(?)]\\/By(ideal)(?) with all flux densities taken for different azimuthal angles ? along a circle of radius r within the quadrupole aperture. Some improvements can be achieved by additional corrective-coils the current through which is not

Alexander Chernosvitov; Alexander Kalimov; Hermann Wollnik

2002-01-01

418

A quadrupole-based mass spectrometric system for the determination of noble gas abundances in fluids  

Microsoft Academic Search

We present details of the operation and performance of a quadrupole mass spectrometer-based system developed for the extraction, separation, and high-precision measurement of noble gases dissolved in fluid samples. The relatively inexpensive quadrupole mass spectrometer system, employed with the isotope dilution technique, achieves a precision for He, Ne, Ar, Kr, and Xe abundances of ±0.4%, ±0.7%, ±0.1%, ±0.8%, and ±0.9%

Justin T. Kulongoski; David R. Hilton

2002-01-01

419

A quadrupole-based mass spectrometric system for the determination of noble gas abundances in fluids  

Microsoft Academic Search

We present details of the operation and performance of a quadrupole mass spectrometer-based system developed for the extraction, separation, and high-precision measurement of noble gases dissolved in fluid samples. The relatively inexpensive quadrupole mass spectrometer system, employed with the isotope dilution technique, achieves a precision for He, Ne, Ar, Kr, and Xe abundances of +\\/-0.4%, +\\/-0.7%, +\\/-0.1%, +\\/-0.8%, and +\\/-0.9%

Justin T. Kulongoski; David R. Hilton

2002-01-01

420

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

421

Design and Construction of the Final Focus Quadrupole R&D Magnet for Super-KEKB  

Microsoft Academic Search

For upgrading the electron-positron collider KEKB, the final focusing magnet system in the beam interaction region has been studied. The designed magnet system consists of five su- perconductingandthreepermanentquadrupolemagnets.Asuper- conducting quadrupole magnet has been constructed as the R&D of this system. In this paper, design and construction of this R&D magnet are reported. Index Terms—Direct winding coil, final focus quadrupole, inter-

Norihito Ohuchi; Kiyosumi Tsuchiya; Masafumi Tawada; Norio Higashi; Masako Iwasaki; Zhanguo Zong

2011-01-01

422

Permanent Magnet Skew Quadrupoles for the Low Emittance LER Lattice of PEP-II  

SciTech Connect

The vertical emittance of the low energy ring (LER) in the PEP-II B-Factory was reduced by using skew quadrupoles consisting of permanent magnet material. The advantages over electric quadrupoles or rotating existing normal quadrupoles are discussed. To assure a high field quality, a Biot-Savart calculation was used to cancel the natural 12-pole component by using different size poles over a few layers. A magnetic measurement confirmed the high quality of the magnets. After installation and adjusting the original electric 12 skew and 16 normal quadrupoles the emittance contribution from the region close to the interaction point, which was the biggest part in the original design, was considerably reduced. To strengthen the vertical behavior of the LER beam, a low emittance lattice was developed. It lowered the original vertical design emittance from 0.54 nm-rad to 0.034 nm-rad. In order to achieve this, additional skew quadrupoles were required to bring the coupling correction out of the arcs and closer to the detector solenoid in the straight (Fig. 1). It is important, together with low vertical dispersion, that the low vertical emittance is not coupled into the horizontal, which is what we get if the coupling correction continues into the arcs. Further details of the lattice work is described in another paper; here we concentrate on the development of the permanent skew (PSK) quadrupole solution. Besides the permanent magnets there are two other possibilities, using electric magnets or rotating normal quadrupoles. Electric magnets would have required much more additional equipment like magnets stands, power supply, and new vacuum chamber sections. Rotating existing quadrupoles was also not feasible since they are mostly mounted together with a bending magnet on the same support girder.

Decker, F.-J.; Anderson, S.; Kharakh, D.; Sullivan, M.; /SLAC

2011-07-05

423

Magnetic Field Measurements of LHC Inner Triplet Quadrupoles Fabricated at Fermilab  

Microsoft Academic Search

Fermilab, as part of the US-LHC Accelerator Project, is producing superconducting low-beta quadrupole magnets for the large hadron collider (LHC). These 5.5 m long magnets are designed to operate in superfluid helium at 1.9 K with a nominal gradient of 205 T\\/m in the 70 mm bore. Two quadrupoles separated by a dipole orbit corrector in a single cryogenic assembly

G. V. Velev; R. Bossert; R. Carcagno; J. Dimarco; S. Feher; V. V. Kashikhin; J. Kerby; M. Lamm; D. Orris; P. Schlabach; J. Strait; C. Sylvester; M. Tartaglia; J. C. Tompkins; A. V. Zlobin

2007-01-01

424

Performance of Nb3Sn quadrupole magnets under localized thermal load  

SciTech Connect

This paper describes the results of design and analyses performed on 120-mm Nb{sub 3}Sn and NbTi quadrupole magnets with parameters relevant for the LHC IR upgrade. A realistic radiation heat load is evaluated in a wide luminosity range and translated into the magnet quench performance. The simulation results are supported by thermal measurements on a 90-mm Nb{sub 3}Sn quadrupole coil.

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

2009-06-01

425

An investigation of the applicability of permanent magnet quadrupole arrays for high-power microwave tubes  

Microsoft Academic Search

Summary form only given, as follows. Magnetic quadrupoles have long been used in accelerator research for focusing high-energy particle beams. The advent of high-field, rare-earth permanent magnet materials has also spurred interest in permanent magnet quadrupoles (PMQ's) since they are more lightweight and compact than their electromagnet counterparts and do not require power supplies or extraneous cooling. We study the

J. H. Booske; M. A. Basten; L. J. Louis; J. Joe; J. E. Scharer

1996-01-01

426

Field quality in Fermilab-built models of quadrupole magnets for the LHC interaction region  

Microsoft Academic Search

Superconducting quadrupole magnets for the interaction regions of the Large Hadron Collider are being developed by the US-LHC Accelerator Project. These 70 mm bore quadrupole magnets are intended to operate in superfluid helium at 1.9 K with a nominal field gradient of 215 T\\/m. A series of 2 m model magnets has been built and cold tested at Fermilab to

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

2001-01-01

427

Field Quality Measurements and Analysis of the LARP Technology Quadrupole Models  

Microsoft Academic Search

One of the US-LHC accelerator research program goals is to develop and prove the design and technology of quadrupoles for an upgrade of the LHC Interaction Region (IR) inner triplets. Four 1-m long technology quadrupole models with a 90 mm bore and field gradient of 200 T\\/m based on similar coils and different mechanical structures have been developed. In this

G. V. Velev; R. Bossert; S. Caspi; G. Chlachidze; J. Dimarco; P. Ferracin; V. V. Kashikhin; M. Lamm; G. L. Sabbi; P. Schlabach; M. Tartaglia; J. C. Tompkins; A. V. Zlobin

2008-01-01

428

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

429

The use of a triple quadrupole linear ion trap mass spectrometer with electrospray ionisation for fragmentation studies of selected antifungal drugs.  

PubMed

Fragmentation studies of three antifungal drugs, clotrimazole, fluconazole and clioquinol ,were performed. A triple quadrupole linear ion trap mass spectrometer was used for this purpose. This type of equipment enables MS(3) spectra to be obtained which lead to better understanding of fragmentation pathways. Nevertheless, it is rarely used for fragmentation studies. The results obtained here for the antifungal drugs gave further insight into fragmentation pathways of clotrimazole and fluconazole. Moreover, fragmentation of clioquinol was investigated which had not been presented before. PMID:21953959

Zgo?a-Grze?kowiak, Agnieszka; Grze?kowiak, Tomasz

2011-10-30

430

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

431

Asymmetry Dependence of the Nuclear Caloric Curve  

NASA Astrophysics Data System (ADS)

A basic feature of the nuclear equation of state is not yet understood: the dependence of the nuclear caloric curve on the neutron-proton asymmetry. Predictions of theoretical models differ on the magnitude and even the sign of this dependence. In this work, the nuclear caloric curve is examined for fully reconstructed quasi-projectiles around mass A = 50. Two independent thermometers, the momentum quadrupole fluctuation thermometer and the Albergo yield ratio thermometer, are used to extract the caloric curve. For both methods, the caloric curve extracted shows that the temperature varies linearly with quasi-projectile asymmetry For the momentum quadrupole fluctuation thermometer, an increase in asymmetry of 0.15 units corresponds to a decrease in temperature on the order of 1 MeV. These results also highlight the importance of a full quasi-projectile reconstruction in the study of thermodynamic properties of hot nuclei.

McIntosh, A. B.; Bonasera, A.; Cammarata, P.; Hagel, K.; Heilborn, L.; Kohley, Z.; Mabiala, J.; May, L. W.; Marini, P.; Raphelt, A.; Souliotis, G. A.; Wuenschel, S.; Zarrella, A.; Yennello, S. J.

2013-03-01

432

Nuclear Physics Laboratory annual report  

SciTech Connect

In the field of nuclear astrophysics, possible sources for nucleosynthesis of YTa/sup m/ were examined. Giant dipole resonances (GDR) built on excited nuclear states were investigated. In particular, (p,el) reactions for one-step semidirect GDR excitations were studied. Quadrupole and higher multipolarity giant resonances were examined with the (el,n) reaction. Using the mass asymmetry of sequential fission fragments, the division of excitation energy in partially damped heavy ion collisions were determined. A new mode of dissociation for the heavy-ion projectile was identified. Departures from free pion-nucleon scattering were examined. Individual reports in these areas were cataloged separately. (WRF)

Trainor, T.A.; Weitkamp, W.G. (eds,)

1984-04-01

433

Nuclear Magnetic Resonance Spectroscopy  

NSDL National Science Digital Library

This website serves as a primer for understanding the fundamentals of NMR spectroscopy. Plenty of useful figures and animations that enhance the understanding of nuclear spin, shielding, and how these phenomena serve as the basis for NMR.

2011-05-18

434

Excitation of transverse dipole and quadrupole modes in a pure ion plasma in a linear Paul trap to study collective processes in intense beams  

SciTech Connect

Transverse dipole and quadrupole modes have been excited in a one-component cesium ion plasma trapped in the Paul Trap Simulator Experiment (PTSX) in order to characterize their properties and understand the effect of their excitation on equivalent long-distance beam propagation. The PTSX device is a compact laboratory Paul trap that simulates the transverse dynamics of a long, intense charge bunch propagating through an alternating-gradient transport system by putting the physicist in the beam's frame of reference. A pair of arbitrary function generators was used to apply trapping voltage waveform perturbations with a range of frequencies and, by changing which electrodes were driven with the perturbation, with either a dipole or quadrupole spatial structure. The results presented in this paper explore the dependence of the perturbation voltage's effect on the perturbation duration and amplitude. Perturbations were also applied that simulate the effect of random lattice errors that exist in an accelerator with quadrupole magnets that are misaligned or have variance in their field strength. The experimental results quantify the growth in the equivalent transverse beam emittance that occurs due to the applied noise and demonstrate that the random lattice errors interact with the trapped plasma through the plasma's internal collective modes. Coherent periodic perturbations were applied to simulate the effects of magnet errors in circular machines such as storage rings. The trapped one component plasma is strongly affected when the perturbation frequency is commensurate with a plasma mode frequency. The experimental results, which help to understand the physics of quiescent intense beam propagation over large distances, are compared with analytic models.

Gilson, Erik P.; Davidson, Ronald C.; Efthimion, Philip C.; Majeski, Richard; Startsev, Edward A.; Wang, Hua [Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)] [Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States); Koppell, Stewart [University of Texas at Austin, Austin, Texas 78712 (United States)] [University of Texas at Austin, Austin, Texas 78712 (United States); Talley, Matthew [Brigham Young University, Provo, Utah 84602 (United States)] [Brigham Young University, Provo, Utah 84602 (United States)

2013-05-15

435

Installation of a cw radiofrequency quadrupole accelerator at Los Alamos National Laboratory  

SciTech Connect

Chalk River Laboratories (CRL) has had a long history of cw proton beam development for production of intense neutron sources and fissile fuel breeders. In 1986 CRL and Los Alamos National Laboratory (LANL) entered into a collaborative effort to establish a base technologies program for the development of a cw radiofrequency quadrupole (RFQ). The initial cw RFQ design had 50-keV proton injection energy with 600-keV output energy. The 75-mA design current at 600-keV beam energy was obtained in 1990. Subsequently, the RFQ output energy was increased to 1250 keV by replacing the RFQ vanes, still maintaining the 75-m A design current. A new 250-kW cw klystrode rf power source at 267-MHz was installed at CRL. By April of 1993, 55-mA proton beams had been accelerated to 1250 keV. Concurrent developments were taking place on proton source development and on 50-keV low-energy beam transport (LEBT) systems. Development of a dc, high-proton fraction ({ge} 70%) microwave ion source led to utilization of a single-solenoid RFQ direct injection scheme. It was decided to continue this cw RFQ demonstration project at Los Alamos when the CRL project was terminated in April 1993. The LANL goals are to find the current limit of the 1250-keV RFQ, better understand the beam transport properties through the single-solenoid focusing LEBT, continue the application of the cw klystrode tube technology to accelerators, and develop a two-solenoid LEBT which could be the front end of an Accelerator-Driven Transmutation Technologies (ADTT) linear accelerator.

Schneider, J.D.; Bolme, J.; Brown, V. [and others

1994-09-01

436

Analysis of spin precession in binary black hole systems including quadrupole-monopole interaction  

SciTech Connect

We analyze in detail the spin precession equations in binary black hole systems, when the tidal torque on a Kerr black hole due to quadrupole-monopole coupling is taken into account. We show that completing the precession equations with this term reveals the existence of a conserved quantity at 2PN order when averaging over orbital motion. This quantity allows one to solve the (orbit-averaged) precession equations exactly in the case of equal masses and arbitrary spins, neglecting radiation reaction. For unequal masses, an exact solution does not exist in closed form, but we are still able to derive accurate approximate analytic solutions. We also show how to incorporate radiation-reaction effects into our analytic solutions adiabatically, and compare the results to solutions obtained numerically. For various configurations of the binary, the relative difference in the accumulated orbital phase computed using our analytic solutions versus a full numerical solution varies from {approx}0.3% to {approx}1.8% over {approx}80-140 orbital cycles accumulated while sweeping over the orbital frequency range {approx}20-300 Hz. This typically corresponds to a discrepancy of order {approx}5-6 radians. While this may not be accurate enough for implementation in LIGO template banks, we still believe that our new solutions are potentially quite useful for comparing numerical relativity simulations of spinning binary black hole systems with post-Newtonian theory. They can also be used to gain more understanding of precession effects, with potential application to the gravitational recoil problem, and to provide semianalytical templates for spinning, precessing binaries.

Racine, Etienne [Maryland Center for Fundamental Physics, Department of Physics, University of Maryland, College Park, Maryland 20742 (United States)

2008-08-15

437

Interfacing an ion mobility spectrometry based explosive trace detector to a triple quadrupole mass spectrometer.  

PubMed

Hardware from a commercial-off-the-shelf (COTS) ion mobility spectrometry (IMS) based explosive trace detector (ETD) has been interfaced to an AB/SCIEX API 2000 triple quadrupole mass spectrometer. To interface the COTS IMS based ETD to the API 2000, the faraday plate of the IMS instrument and the curtain plate of the mass spectrometer were removed from their respective systems and replaced by a custom faraday plate, which was fabricated with a hole for passing the ion beam to the mass spectrometer, and a custom interface flange, which was designed to attach the IMS instrument onto the mass spectrometer. Additionally, the mass spectrometer was modified to increase the electric field strength and decrease the pressure in the differentially pumped interface, causing a decrease in the effect of collisional focusing and permitting a mobility spectrum to be measured using the mass spectrometer. The utility of the COTS-ETD/API 2000 configuration for the characterization of the gas phase ion chemistry of COTS-ETD equipment was established by obtaining mass and tandem mass spectra in the continuous ion flow and selected mobility monitoring operating modes and by obtaining mass-selected ion mobility spectra for the explosive standard 2,4,6 trinitrotoluene (TNT). This analysis confirmed that the product ion for TNT is [TNT - H](-), the predominant collision-induced dissociation pathway for [TNT- H](-) is the loss of NO and NO(2), and the reduced mobility value for [TNT - H](-) is 1.54 cm(2)V(-1) s(-1). Moreover, this analysis was attained for sample amounts of 1 ng and with a resolving power of 37. The objective of the research is to advance the operational effectiveness of COTS IMS based ETD equipment by developing a platform that can facilitate the understanding of the ion chemistry intrinsic to the equipment. PMID:22017332

Kozole, Joseph; Stairs, Jason R; Cho, Inho; Harper, Jason D; Lukow, Stefan R; Lareau, Richard T; DeBono, Reno; Kuja, Frank

2011-11-15

438

Final Development and Test Preparation of the First 3.7 m Long Nb3Sn Quadrupole by LARP  

Microsoft Academic Search

The test of the first LARP (LHC Accelerator Research Program) Long Quadrupole is a significant milestone toward the development of Nb3Sn quadrupoles for LHC (Large Hadron Collider) Luminosity Upgrades. These 3.7-m long magnets, scaled from the 1-m long Technological Quadrupoles, are used to develop our capabilities to fabricate and assemble Nb3Sn coils and structures with lengths comparable to accelerator magnet

G. Ambrosio; N. Andreev; M. Anerella; E. Barzi; B. Bingham; D. Bocian; B. Bordini; R. Bossert; L. Bottura; S. Caspi; G. Chlachidize; W. M. De Rapper; D. Dietderich; J. Escallier; H. Felice; P. Ferracin; A. Ghosh; A. Godeke; R. Hannaford; G. Jochen; V. V. Kashikhin; P. Kovach; M. Lamm; A. McInturff; J. Muratore; F. Nobrega; I. Novitsky; D. Orris; S. Peggs; E. Prebys; S. Prestemon; G. L. Sabbi; J. Schmalzle; C. Sylvester; M. Tartaglia; D. Turrioni; G. Velev; P. Wanderer; G. Willering; A. V. Zlobin

2010-01-01

439

Systematically Asymmetric Heliospheric Magnetic Field: Evidence for a Quadrupole Mode and Non-Axisymmetry with Polarity Flip-Flops  

NASA Astrophysics Data System (ADS)

Recent studies of the heliospheric magnetic field (HMF) have detected interesting, systematic hemispherical and longitudinal asymmetries which have a profound significance for the understanding of solar magnetic fields. The in situ HMF measurements since the 1960s show that the heliospheric current sheet (HCS) is systematically shifted (coned) southward during solar minimum times, leading to the concept of a bashful ballerina. While temporary shifts can be considerably larger, the average HCS shift (coning) angle is a few degrees, less than the 7.2? tilt of the solar rotation axis. Recent solar observations during the last two solar cycles verify these results and show that the magnetic areas in the northern solar hemisphere are larger and their intensity weaker than in the south during long intervals in the late declining to minimum phase. The multipole expansion reveals a strong quadrupole term which is oppositely directed to the dipole term. These results imply that the Sun has a symmetric quadrupole S0 dynamo mode that oscillates in phase with the dominant dipole A0 mode. Moreover, the heliospheric magnetic field has a strong tendency to produce solar tilts that are roughly opposite in longitudinal phase. This implies is a systematic longitudinal asymmetry and leads to a “flip-flop” type behaviour in the dominant HMF sector whose period is about 3.2 years. This agrees very well with the similar flip-flop period found recently in sunspots, as well as with the observed ratio of three between the activity cycle period and the flip-flop period of sun-like stars. Accordingly, these results require that the solar dynamo includes three modes, A0, S0 and a non-axisymmetric mode. Obviously, these results have a great impact on solar modelling.

Mursula, K.; Hiltula, T.

2004-10-01

440

Origin-independent calculation of quadrupole intensities in X-ray spectroscopy  

SciTech Connect

For electronic excitations in the ultraviolet and visible range of the electromagnetic spectrum, the intensities are usually calculated within the dipole approximation, which assumes that the oscillating electric field is constant over the length scale of the transition. For the short wavelengths used in hard X-ray spectroscopy, the dipole approximation may not be adequate. In particular, for metal K-edge X-ray absorption spectroscopy (XAS), it becomes necessary to include higher-order contributions. In quantum-chemical approaches to X-ray spectroscopy, these so-called quadrupole intensities have so far been calculated by including contributions depending on the square of the electric-quadrupole and magnetic-dipole transition moments. However, the resulting quadrupole intensities depend on the choice of the origin of the coordinate system. Here, we show that for obtaining an origin-independent theory, one has to include all contributions that are of the same order in the wave vector consistently. This leads to two additional contributions depending on products of the electric-dipole and electric-octupole and of the electric-dipole and magnetic-quadrupole transition moments, respectively. We have implemented such an origin-independent calculation of quadrupole intensities in XAS within time-dependent density-functional theory, and demonstrate its usefulness for the calculation of metal and ligand K-edge XAS spectra of transition metal complexes.

Bernadotte, Stephan; Atkins, Andrew J.; Jacob, Christoph R. [Karlsruhe Institute of Technology (KIT), Center for Functional Nanostructures and Institute of Physical Chemistry, Wolfgang-Gaede-Str. 1a, 76131 Karlsruhe (Germany)

2012-11-28

441

Laboratory measurements and theoretical calculations of O2 A band electric quadrupole transitions  

NASA Astrophysics Data System (ADS)

Frequency-stabilized cavity ring-down spectroscopy was utilized to measure electric quadrupole transitions within the O162 A band, b?1g+?X?3g-(0,0) . We report quantitative measurements (relative uncertainties in intensity measurements from 4.4% to 11%) of nine ultraweak transitions in the ON , OP , SR , and ST branches with line intensities ranging from 3×10-30 to 2×10-29cmmolec.-1 . A thorough discussion of relevant noise sources and uncertainties in this experiment and other cw-cavity ring-down spectrometers is given. For short-term averaging (t<100s) , we estimate a noise-equivalent absorption of 2.5×10-10cm-1Hz-1/2 . The detection limit was reduced further by co-adding up to 100 spectra to yield a minimum detectable absorption coefficient equal to 1.8×10-11cm-1 , corresponding to a line intensity of ˜2.5×10-31cmmolec.-1 . We discuss calculations of electric quadrupole line positions based on a simultaneous fit of the ground and upper electronic state energies which have uncertainties <3MHz , and we present calculations of electric quadrupole matrix elements and line intensities. The electric quadrupole line intensity calculations and measurements agreed on average to 5%, which is comparable to our average experimental uncertainty. The calculated electric quadrupole band intensity was 1.8(1)×10-27cmmolec.-1 which is equal to only ˜8×10-6 of the magnetic dipole band intensity.

Long, D. A.; Havey, D. K.; Okumura, M.; Pickett, H. M.; Miller, C. E.; Hodges, J. T.

2009-10-01

442

Origin-independent calculation of quadrupole intensities in X-ray spectroscopy  

NASA Astrophysics Data System (ADS)

For electronic excitations in the ultraviolet and visible range of the electromagnetic spectrum, the intensities are usually calculated within the dipole approximation, which assumes that the oscillating electric field is constant over the length scale of the transition. For the short wavelengths used in hard X-ray spectroscopy, the dipole approximation may not be adequate. In particular, for metal K-edge X-ray absorption spectroscopy (XAS), it becomes necessary to include higher-order contributions. In quantum-chemical approaches to X-ray spectroscopy, these so-called quadrupole intensities have so far been calculated by including contributions depending on the square of the electric-quadrupole and magnetic-dipole transition moments. However, the resulting quadrupole intensities depend on the choice of the origin of the coordinate system. Here, we show that for obtaining an origin-independent theory, one has to include all contributions that are of the same order in the wave vector consistently. This leads to two additional contributions depending on products of the electric-dipole and electric-octupole and of the electric-dipole and magnetic-quadrupole transition moments, respectively. We have implemented such an origin-independent calculation of quadrupole intensities in XAS within time-dependent density-functional theory, and demonstrate its usefulness for the calculation of metal and ligand K-edge XAS spectra of transition metal complexes.

Bernadotte, Stephan; Atkins, Andrew J.; Jacob, Christoph R.

2012-11-01

443

Design of large aperture superferric quadrupole magnets for an in-flight fragment separator  

NASA Astrophysics Data System (ADS)

Superferric quadrupole magnets to be used for in-flight fragment separator have been designed. A quadrupole magnet triplet for beam focusing is placed in a cryostat together with superconducting correction coils. To maximize acceptance of rare isotope beams produced by projectile fragmentation, it is essential to use large-aperture quadrupole magnets. The pole tip radius is 17 cm in the current design, and we tried to enlarge the aperture with 3D analysis on magnetic fields. In the front end of the separator, where a target and beam dump are located, we plan to use two sets of quadrupole triplets made of high-Tc superconductor (HTS) operating at 20-50 K considering high radiation heat load. The HTS magnet will use warm iron poles. Both low-Tc and high-Tc superconductors are acquired for test winding, and two kinds of dewar and cryostat are under construction to perform the coil and magnet tests. The magnetic design of superferric quadrupole is mainly discussed.

Zaghloul, Aziz; Kim, Dogyun; Kim, Jangyoul; Kim, Mijung; Kim, Myeongjin; Yun, Chongcheoul; Kim, Jongwon

2014-01-01

444

Molecular structure, nuclear quadrupole coupling constant and dipole moment of nitrogen trichloride from microwave spectroscopy  

Microsoft Academic Search

The rotational constants of four isotopic species of nitrogen trichloride have been obtained from transitions in the millimeter region. Two rs structures have been obtained with the following average values of the parameters. rN-C1=1.7535 +\\/- 0.0020 A.The Stark effect of the J = 3 <-- 2 transition was analyzed to obtaine the value 0.39 +\\/- 0.01 D for the dipole

G. Cazzoli; P. G. Favero; A. dal Borgo

1974-01-01

445

Triaxial quadrupole deformation dynamics in sd-shell nuclei around {sup 26}Mg  

SciTech Connect

Large-amplitude dynamics of axial and triaxial quadrupole deformation in {sup 24,26}Mg, {sup 24}Ne, and {sup 28}Si is investigated on the basis of the quadrupole collective Hamiltonian constructed with the use of the constrained Hartree-Fock-Bogoliubov plus the local quasiparticle random-phase approximation method. The calculation reproduces well properties of the ground rotational bands, and {beta} and {gamma} vibrations in {sup 24}Mg and {sup 28}Si. The {gamma} softness in the collective states of {sup 26}Mg and {sup 24}Ne are discussed. Contributions of the neutrons and protons to the transition properties are also analyzed in connection with the large-amplitude quadrupole dynamics.

Hinohara, Nobuo [Theoretical Nuclear Physics Laboratory, RIKEN Nishina Center, RIKEN, Wako, Saitama 351-0198 (Japan); Kanada-En'yo, Yoshiko [Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502 (Japan)

2011-01-15

446

Calculations and measurements for the SLAC SLC positron return quadrupole magnet  

SciTech Connect

The three-dimensional magnetostatic computer program TOSCA, running on the NMFECC CRAY X-MP computer, was used to compute the integral of gradient length for the SLC type QT4 positron return line quadrupole magnet. Since the bore diameter of the magnet is 12.7 centimeters, and the length is only 10.16 centimeters, three dimensional effects are important. POISSON calculations were done on a two-dimensional model to obtain magnetic shimming which assured enough positive twelve pole to offset end effects, while TOSCA was used to estimate the effective length of the quadrupole. No corrections were required on the magnet as built. Measurements showed that the required integrated gradient was achieved for the given current, and that integrated higher harmonics were generally less than 0.1% of the quadrupole component.

Early, R.A.; Cobb, J.K.

1986-09-01

447

Electrons in a Positive-Ion Beam with Solenoid or Quadrupole Magnet Transport  

SciTech Connect

The High Current Experiment (HCX) is used to study beam transport and accumulation of electrons in quadrupole magnets and the Neutralized Drift-Compression Experiment (NDCX) to study beam transport through and accumulation of electrons in magnetic solenoids. We find that both clearing and suppressor electrodes perform as intended, enabling electron cloud densities to be minimized. Then, the measured beam envelopes in both quadrupoles and solenoids agree with simulations, indicating that theoretical beam current transport limits are reliable, in the absence of electrons. At the other extreme, reversing electrode biases with the solenoid transport effectively traps electrons; or, in quadrupole magnets, grounding the suppressor electrode allows electron emission from the end wall to flood the beam, in both cases producing significant degradation in the beam.

Molvik, A W; Cohen, R H; Friedman, A; Covo, M K; Lund, S M; Sharp, W M; Seidl, P A; Bieniosek, F M; Coleman, J E; Faltens, A; Roy, P K; Vay, J L; Prost, L

2007-06-01

448

Electrons in a positive-ion beam with solenoid or quadrupole magnetic transport  

SciTech Connect

The High Current Experiment (HCX) is used to study beam transport and accumulation of electrons in quadrupole magnets and the Neutralized Drift-Compression Experiment (NDCX) to study beam transport through and accumulation of electrons in magnetic solenoids. We find that both clearing and suppressor electrodes perform as intended, enabling electron cloud densities to be minimized. Then, the measured beam envelopes in both quadrupoles and solenoids agree with simulations, indicating that theoretical beam current transport limits are reliable, in the absence of electrons. At the other extreme, reversing electrode biases with the solenoid transport effectively traps electrons; or, in quadrupole magnets, grounding the suppressor electrode allows electron emission from the end wall to flood the beam, in both cases producing significant degradation in the beam.

Molvik, A.W.; Kireeff Covo, M.; Cohen, R.; Coleman, J.; Sharp, W.; Bieniosek, F.; Friedman, A.; Roy, P.K.; Seidl, P.; Lund, S.M.; Faltens, A.; Vay, J.L.; Prost, L.

2007-06-04

449

Physical origin of the quadrupole out-of-plane magnetic field in Hall-magnetohydrodynamic reconnection  

SciTech Connect

A quadrupole pattern of the out-of-plane component of the magnetic field inside a reconnection region is seen as an important signature of the Hall-magnetohydrodynamic regime of reconnection. It has been first observed in numerical simulations and just recently confirmed in the Magnetic Reconnection Experiment [Y. Ren, M. Yamada, S. Gerhardt, H. Ji, R. Kulsrud, and A. Kuritsin, Phys. Rev. Lett. 95, 055003 (2005)] and also seen in spacecraft observations of Earth's magnetosphere. In this study, the physical origin of the quadrupole field is analyzed and traced to a current of electrons that flows along the lines in and out of the inner reconnection region to maintain charge neutrality. The role of the quadrupole magnetic field in the overall dynamics of the reconnection process is discussed. In addition, the bipolar poloidal electric field is estimated and its effect on ion motions is emphasized.

Uzdensky, Dmitri A.; Kulsrud, Russell M. [Princeton University Observatory and Princeton Plasma Physics Laboratory- Center for Magnetic Self-Organization (CMSO), Princeton, New Jersey 08544 (United States)

2006-06-15

450

Design, test and performance of the prototype superconducting quadrupole for the LEP low-beta insertions  

SciTech Connect

The prototype of the superconducting quadrupoles for the low-beta insertions at the LEP e/sup +/e/sup -/ collider, presently under construction at CERN, has been successfully tested. This industry-built quadrupole, which has a warm bore of 130 mm and a magnetic length of 2 m, is required to provide a gradient of 36 T m/sup -1/ over a good field aperture of 100 mm in diameter. It achieved its maximum operating current without training. While retaining the main characteristics of its ISR predecessors, the design of this magnet also incorporates several novel features, due to constraints imposed by the environment of the LEP experiments. In particular, the quadrupole is slender, ironless, and has a horizontally-oriented cryogenic service funnel. Following a description of the major aspects of the design of the magnet, the results are given of the magnetic cryogenic tests and measurements.

Lebrun, P.; Pichler, S.; Taylor, T.M.; Tortschanoff, T.; Walckiers, L.

1988-03-01

451

Magnetic field measurements of LHC inner triplet quadrupoles fabricated at Fermilab  

SciTech Connect

Fermilab, as part of the US-LHC Accelerator Project, is producing superconducting low-beta quadrupole magnets for the Large Hadron Collider (LHC). These 5.5 m long magnets are designed to operate in superfluid helium at 1.9 K with a nominal gradient of 205 T/m in the 70 mm bore. Two quadrupoles separated by a dipole orbit corrector in a single cryogenic assembly comprise the Q2 optical elements of the final focus triplets in the LHC interaction regions. The field quality of the quadrupoles is measured at room temperature during construction of the cold masses as well as during cold testing of the cryogenic assembly. We summarize data from the series measurements of the magnets and discuss various topics of interest.

Velev, G.V.; Bossert, R.; Carcagno, R.; DiMarco, J.; Feher, S.; Kashikhin, V.V.; Kerby, J.; Lamm, M.; Orris, D.; Schlabach, P.; Strait, J.; /Fermilab

2006-08-01

452

Students' Understanding of Tides.  

ERIC Educational Resources Information Center

Reports the findings of research into students' understanding of tides. Students from secondary school and pre-service primary school teacher trainees were chosen as subjects and their understanding was assessed by questionnaire. (Author/CCM)

Viiri, Jouni

2000-01-01

453

Understanding Brain Tumors  

MedlinePLUS

... org > Brain Tumor Information > Understanding Brain Tumors Understanding Brain Tumors While it is normal to feel scared, ... to Know About Brain Tumors . What is a Brain Tumor? A brain tumor is an abnormal growth? ...

454

Understanding Cancer Series: Cancer  

MedlinePLUS

... Cancer Statistics Research & Funding News About NCI Understanding Cancer Series Posted: 01/28/2005 Reviewed: 09/30/ ... Search for Clinical Trials NCI Publications Español Understanding Cancer Series: Cancer Slide Number and Title What is ...

455

Mitigating radiation loads in Nb(3)Sn quadrupoles for LHC upgrades  

SciTech Connect

Challenging beam-induced energy deposition issues are addressed for the next generation of the LHC high-luminosity interaction regions based on Nb{sub 3}Sn quadrupoles. Detailed MARS15 Monte Carlo energy deposition calculations are performed for various coil diameters, thicknesses and materials of the inner absorber at a field gradient of 200 T/m. It is shown that using the inner absorber made of tungsten-based materials can make the final focus superconducting quadrupoles compatible with a luminosity of 10{sup 35} cm{sup -2}s{sup -1}.

Mokhov, N.V.; Rakhno, I.L.; /Fermilab

2006-08-01

456

A superconducting cos 2theta quadrupole design for the CEBAF high resolution spectrometer  

SciTech Connect

The pair of High Resolution Spectrometers (HRS{sup 2}) at CEBAF require large aperture, high gradient quadrupoles. A superconducting cos 2theta is under consideration to meet these requirements. The quadrupole has a coil diameter of 1m and a peak gradient of 5 T/m with an effective field length of 1.8 m. The stored energy of this quad is 3.0 MJ. The details of the design of the coil, shrink fit support collar and cryostat are presented. The analysis of the superconductor, quench behavior and coil protection system is covered.

Walter Tuzel; Sirish Nanda; Jean Mougey; Alan Gavalya; Paul Brindza; John Alcorn

1989-03-01

457

Low-lying bands with different quadrupole deformation in 155Dy  

NASA Astrophysics Data System (ADS)

To investigate the interplay between collective and single particle degrees of freedom in odd nuclei, Recoil distance Doppler-shift and Doppler-shift attenuation lifetime measurements were carried out for levels in 155Dy in coincidence detection of gamma-rays. 26 lifetimes were determined using the Differential decay curve method. Particle plus triaxial rotor model (PTRM) calculations were performed to compare the experimental level scheme and transition strengths with theoretical ones in order to get information on the quadrupole deformation (?,?) of the bands. As a result, different quadrupole deformations for the one-quasineutron bands at low and medium spins are deduced.

Petkov, P.; Yavahchova, M. S.; Möller, O.; Dewald, A.; Saha, B.; Fitzler, A.; Jessen, K.; Tonev, D.; Klug, T.; Heinze, S.; Jolie, J.; von Brentano, P.; Goutev, N.; Bazzacco, D.; Ur, C. A.; Farnea, C. A.; Axiotis, M.; Lunardi, S.; de Angelis, G.; Napoli, D. R.; Marginean, N.; Martinez, T.; Caprio, M. A.

2014-03-01

458

Engineering quadrupole magnetic flow sorting for the isolation of pancreatic islets  

NASA Astrophysics Data System (ADS)

Quadrupole magnetic flow sorting (QMS) is being adapted from the separation of suspensions of single cells (<15 ?m) to the isolation of pancreatic islets (150-350 ?m) for transplant. To achieve this goal, the critical QMS components have been modeled and engineered to optimize the separation process. A flow channel has been designed, manufactured, and tested. The quadrupole magnet assembly has been designed and verified by finite element analysis. Pumps have been selected and verified by test. Test data generated from the pumps and flow channel demonstrate that the fabricated channel and peristaltic pumps fulfill the requirements of successful QMS separation.

Kennedy, David J.; Todd, Paul; Logan, Sam; Becker, Matthew; Papas, Klearchos K.; Moore, Lee R.

2007-04-01

459

Quadrupole Moments for Isomeric States with Normal and Intruder Configurations in Neutron-Deficient Pb Nuclei  

NASA Astrophysics Data System (ADS)

The quadrupole interaction of the 11- and 12+ isomers in 192,194Pb nuclei has been investigated in the electric field gradient of metallic Bi polycrystalline lattice by the method of time-differential observation of the gamma -rays perturbed angular distribution. The electric field gradient strength of the host Bi lattice has been calibrated by using as probe the 12+ isomer in 194Pb. The int