Science.gov

Sample records for quadrupole resonance nqr

  1. Explosives detection by nuclear quadrupole resonance (NQR)

    NASA Astrophysics Data System (ADS)

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

    1994-10-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2006-05-01

    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.

  3. Nuclear quadrupole resonance detection of explosives: an overview

    NASA Astrophysics Data System (ADS)

    Miller, Joel B.

    2011-06-01

    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.

  4. Land mine detection by nuclear quadrupole resonance

    NASA Astrophysics Data System (ADS)

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

    1998-09-01

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

  5. Methyl quantum tunneling and nitrogen-14 NQR NMR studies using a SQUID magnetic resonance spectrometer

    SciTech Connect

    Black, B.E. |

    1993-07-01

    Nuclear Magnetic Resonance (NMR) and Nuclear Quadrupole Resonance (NQR) techniques have been very successful in obtaining molecular conformation and dynamics information. Unfortunately, standard NMR and NQR spectrometers are unable to adequately detect resonances below a few megahertz due to the frequency dependent sensitivity of their Faraday coil detectors. For this reason a new spectrometer with a dc SQUID (Superconducting Quantum Interference Device) detector, which has no such frequency dependence, has been developed. Previously, this spectrometer was used to observe {sup 11}B and {sup 27}Al NQR resonances. The scope of this study was increased to include {sup 23}Na, {sup 51}V, and {sup 55}Mn NQR transitions. Also, a technique was presented to observe {sup 14}N NQR resonances through cross relaxation of the nitrogen polarization to adjacent proton spins. When the proton Zeeman splitting matches one nitrogen quadrupoler transition the remaining two {sup 14}N transitions can be detected by sweeping a saturating rf field through resonance. Additionally, simultaneous excitation of two nitrogen resonances provides signal enhancement which helps to connect transitions from the same site. In this way, nitrogen-14 resonances were observed in several amino acids and polypeptides. This spectrometer has also been useful in the direct detection of methyl quantum tunneling splittings at 4.2 K. Tunneling, frequencies of a homologous series of carboxylic acids were measured and for solids with equivalent crystal structures, an exponential correlation between the tunneling frequency and the enthalpy of fusion is observed. This correlation provides information about the contribution of intermolecular interactions to the energy barrier for methyl rotation.

  6. Specific Heat and Nuclear Quadrupole Resonance Study of Thiourea-Hexachloroethane Inclusion Compound

    NASA Astrophysics Data System (ADS)

    Chekhova, G. N.; Goren, S. D.; Krieger, Ju. H.; Linsky, D.; Lusternik, V.; Panich, A. M.; Semenov, A. R.; Voronel, A.

    2000-02-01

    Specific heat and 35Cl nuclear quadrupole resonance (NQR) measurements of the channel thio-urea-hexachloroethane inclusion compound are presented. Experimental NQR data confirm the results of atom-atom potential calculations that the guest sublattice comprises two types of nearly commensurate finite molecular chains, having different structure and separated by domain walls. Specific heat measurements show phase transition near 96 K.

  7. Nuclear magnetic and quadrupole resonance studies of the stripes materials

    NASA Astrophysics Data System (ADS)

    Grafe, H.-J.

    2012-11-01

    Nuclear Magnetic and Quadrupole Resonance (NMR/NQR) is a powerful tool to probe electronic inhomogeneities in correlated electron systems. Its local character allows for probing different environments due to spin density modulations or inhomogeneous doping distributions emerging from the correlations in these systems. In fact, NMR/NQR is not only sensitive to magnetic properties through interaction of the nuclear spin, but also allows to probe the symmetry of the charge distribution and its homogeneity, as well as structural modulations, through sensitivity to the electric field gradient (EFG). We review the results of NMR and NQR in the cuprates from intrinsic spatial variations of the hole concentration in the normal state to stripe order at low temperatures, thereby keeping in mind the influence of doping induced disorder and inhomogeneities. Finally, we briefly discuss NQR evidence for local electronic inhomogeneities in the recently discovered iron pnictides, suggesting that electronic inhomogeneities are a common feature of correlated electron systems.

  8. Optimal filtering in multipulse sequences for nuclear quadrupole resonance detection

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    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.

  9. Applications of nuclear quadrupole resonance spectroscopy in drug development.

    PubMed

    Latosin?ska, Jolanta N

    2007-02-01

    In this review, fundamentals of nuclear quadrupole resonance (NQR) spectroscopy are briefly outlined. Examples of its applications in drug development are discussed to demonstrate that the NQR method is a sophisticated, non-destructive and valuable analytical technique for studying pharmaceuticals, providing effective assistance at the two main steps of drug development: the physical and chemical characterization of the active pharmaceutical ingredients (API) at the analytical step and API development. This review covers different aspects of the use of NQR spectroscopy for drug development and analysis and illustrates the power and versatility of this method in the determination of impurities, polymorphic forms, the drug's structure and conformation, characterization of the interactions between the drug and ligands, search for analogs (second- or third-generation drugs) and the drug's thermal stability. Lastly, NQR advantages and restrictions in the aspect of application in drug development studies are summarized. PMID:23496079

  10. Detecting body cavity bombs with nuclear quadrupole resonance

    NASA Astrophysics Data System (ADS)

    Collins, Michael London

    Nuclear Quadrupole Resonance (NQR) is a technology with great potential for detecting hidden explosives. Past NQR research has studied the detection of land mines and bombs concealed within luggage and packages. This thesis focuses on an NQR application that has received less attention and little or no publicly available research: detecting body cavity bombs (BCBs). BCBs include explosives that have been ingested, inserted into orifices, or surgically implanted. BCBs present a threat to aviation and secure facilities. They are extremely difficult to detect with the technology currently employed at security checkpoints. To evaluate whether or not NQR can be used to detect BCBs, a computational model is developed to assess how the dielectric properties of biological tissue affect the radio frequency magnetic field employed in NQR (0.5-5MHz). The relative permittivity of some biological tissue is very high (over 1,000 at 1MHz), making it conceivable that there is a significant effect on the electromagnetic field. To study this effect, the low-frequency approximation known as the Darwin model is employed. First, the electromagnetic field of a coil is calculated in free space. Second, a dielectric object or set of objects is introduced, and the free-space electric field is modified to accommodate the dielectric object ensuring that the relevant boundary conditions are obeyed. Finally, the magnetic field associated with the corrected electric field is calculated. This corrected magnetic field is evaluated with an NQR simulation to estimate the impact of dielectric tissue on NQR measurements. The effect of dielectric tissue is shown to be small, thus obviating a potential barrier to BCB detection. The NQR model presented may assist those designing excitation and detection coils for NQR. Some general coil design considerations and strategies are discussed.

  11. Low-frequency nuclear quadrupole resonance with a dc SQUID

    SciTech Connect

    Chang, J.W.

    1991-07-01

    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.

  12. Narcotics and explosives detection by 14N pure nuclear quadrupole resonance

    NASA Astrophysics Data System (ADS)

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

    1994-03-01

    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.

  13. Modified steady-state free precession pulse sequences for the detection of pure nuclear quadrupole resonance.

    PubMed

    Rudakov, T N; Mikhaltsevitch, V T; Flexman, J H

    2004-01-01

    Modifications of the steady-state free precession multi-pulse technique for the effective detection of the nuclear quadrupole resonance (NQR) signals are proposed. These modifications are based on the use of composite pulses and enable the suppression of the coherent noise signals such as the magneto-acoustic and piezo-electric signals or the ringing signal from the NQR probe. Experimental results of applying the proposed technique to nitrogen-14 NQR in the sample of C6H12N4 are also presented and convincingly demonstrate its effectiveness. PMID:14698393

  14. Feasibility of nuclear quadrupole resonance as a novel dosimetry tool

    SciTech Connect

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

    1990-01-01

    Nuclear quadrupole resonance (N.Q.R) frequencies are influenced by the symmetry of the charge distribution of a compound around the site of interest. Damage by ionizing radiation causes changes in this charge symmetry which can be detected by standard pulsed N.Q.R. methods. Previous work done on various chlorates of [sup 35]Cl at room temperature (Vargas et al., 1978) shows a linear effect between absorbed gammadose and the N.Q.R. frequency shift and line broadening. This paper reviews the theory of N.Q.R. and details our experimental apparatus. The accumulated data on [sup 14]N-containing compounds, both irradiated and nonirradiated, is discussed. The long term goal of this research is to choose an appropriate organic compound to duplicate the effects of radiation on human tissue. Under such conditions, we may be able to extend this work to provide a mixed radiation field (gamma and neutron) dosimeter which does not require knowing quality factors or energy fluences.

  15. Feasibility of nuclear quadrupole resonance as a novel dosimetry tool

    SciTech Connect

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

    1990-12-31

    Nuclear quadrupole resonance (N.Q.R) frequencies are influenced by the symmetry of the charge distribution of a compound around the site of interest. Damage by ionizing radiation causes changes in this charge symmetry which can be detected by standard pulsed N.Q.R. methods. Previous work done on various chlorates of {sup 35}Cl at room temperature (Vargas et al., 1978) shows a linear effect between absorbed gammadose and the N.Q.R. frequency shift and line broadening. This paper reviews the theory of N.Q.R. and details our experimental apparatus. The accumulated data on {sup 14}N-containing compounds, both irradiated and nonirradiated, is discussed. The long term goal of this research is to choose an appropriate organic compound to duplicate the effects of radiation on human tissue. Under such conditions, we may be able to extend this work to provide a mixed radiation field (gamma and neutron) dosimeter which does not require knowing quality factors or energy fluences.

  16. PEANUT experiment in NQR spectroscopy for I=3/2.

    PubMed

    Sinyavsky, Nikolay; Dolinenkov, Philip; Ma?kowiak, Mariusz

    2012-01-01

    The experiment with phase inversion and phase-inverted echo-amplitude detected nutation (PEANUT) was introduced in the nuclear quadrupole resonance (NQR). Formulas were obtained describing the NQR (I=3/2) experiment. Exemplary experiments are provided confirming the predicted particularities of the PEANUT spectra in NQR Cl-35. It is proposed to apply the method for the purpose of determination the asymmetry parameter of the electric field gradient (EFG) tensor in powders with the help of the analysis of PEANUT interferograms. Application of two-dimensional PEANUT experiments, in which the nutation frequencies correlate with the resonance NQR frequencies, can substantially simplify the interpretation of complex spectra. PMID:22365993

  17. Detection of RDX and TNT mine-like targets by nuclear quadrupole resonance

    NASA Astrophysics Data System (ADS)

    Deas, Robert M.; Burch, Ian A.; Port, Daniel M.

    2002-08-01

    Nuclear quadrupole resonance (NQR) is being researched in order to confirm the presence of explosives as part of landmine sensor suites for the UK MOD hand held and vehicle mounted detection applied research programs. A low power NQR system has been developed as a non-contacting, but short range, detection method for explosives typically found in landmines. The results of stand-off detection of buried anti-personnel and anti-tank quantities of RDX and TNT by this system are presented and the differences in the detection of these explosives by NQR are discussed. Signal processing and radio frequency interference rejection methods to improve the performance of NQR explosive detection have been investigated.

  18. 14 N NQR spectrum of sildenafil citrate

    NASA Astrophysics Data System (ADS)

    Stephenson, David; Singh, Nadia

    2015-04-01

    The 14N nuclear quadrupole resonance (NQR) spectrum of sildenafil citrate tablets has been recorded allowing the quadrupole coupling constants and asymmetry parameters of all six unique nitrogen atoms in its structure to be determined. A density function calculation gives results that are largely in agreement with the experimental values.

  19. Nuclear magnetic and quadrupole resonance in metallic powders in the presence of strong quadrupole interaction: Rhenium metal

    SciTech Connect

    Dimitropoulos, C.; Maglione, M.; Borsa, F.

    1988-03-01

    The nuclear-magnetic-resonance and nuclear-quadrupole-resonance (NQR-NMR) spectra of /sup 187/Re and /sup 185/Re in a powder of rhenium metal were measured in the temperature range 5--10 K both in zero field and with an external magnetic field. The zero-field NQR spectrum is severely broadened by a nonuniform distribution of quadrupole interactions. The average quadrupole coupling frequencies measured at 5 K are, for the two isotopes, ..nu../sub Q/ = 39 +- 0.2 MHz (/sup 187/Re) and ..nu../sub Q/ = 40.8 +- 0.3 MHz (/sup 185/Re). The spectra obtained in the presence of an external magnetic field can be interpreted satisfactorily in terms of transitions among the eigenstates of the full Hamiltonian (Zeeman plus quadrupolar). Measurements of relaxation rates yield T/sub 1/T = 0.03 sK, indicating a relaxation mechanism driven by the hyperfine interaction with the conduction electrons. The feasibility of NQR-NMR studies in small metal particles in the presence of strong inhomogeneous quadrupole interactions is assessed

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

    SciTech Connect

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

    1998-06-01

    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.

  1. A novel power amplification scheme for nuclear magnetic resonance/nuclear quadrupole resonance systems.

    PubMed

    Zhang, Xinwang; Schemm, Nathan; Balk?r, Sina

    2011-03-01

    Nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR)-based chemical analysis systems have been widely utilized in various areas such as medicine, security, and academic research. In these applications, the power amplifier stage plays a key role in generating the required oscillating magnetic fields within a radio frequency coil that serves as the probe. However, the bulky size and relatively low efficiency of the traditional power amplification schemes employed present a bottleneck for the realization of compact sized and portable NMR and NQR systems. To address this problem, this work presents a class D voltage-switching power amplification scheme with novel fast-start and fast-stop functions that are suitable for generating ideal NMR and NQR excitation signals. Compared to the traditional analog power amplifiers (PAs), the proposed switched-mode PA can achieve significant improvement on the power efficiency as well as the physical volume. A PA circuit for portable NQR-based explosive detection systems has been designed and built using the proposed scheme with 1 kW possible maximum output power and 10 MHz maximum operating frequency. Test results show that the presented PA achieves more than 60% measured efficiency within a highly compact volume while sustaining fast start and stop of excitation signals in the order of microseconds. PMID:21456776

  2. A novel power amplification scheme for nuclear magnetic resonance/nuclear quadrupole resonance systems

    NASA Astrophysics Data System (ADS)

    Zhang, Xinwang; Schemm, Nathan; Balk?r, Sina

    2011-03-01

    Nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR)-based chemical analysis systems have been widely utilized in various areas such as medicine, security, and academic research. In these applications, the power amplifier stage plays a key role in generating the required oscillating magnetic fields within a radio frequency coil that serves as the probe. However, the bulky size and relatively low efficiency of the traditional power amplification schemes employed present a bottleneck for the realization of compact sized and portable NMR and NQR systems. To address this problem, this work presents a class D voltage-switching power amplification scheme with novel fast-start and fast-stop functions that are suitable for generating ideal NMR and NQR excitation signals. Compared to the traditional analog power amplifiers (PAs), the proposed switched-mode PA can achieve significant improvement on the power efficiency as well as the physical volume. A PA circuit for portable NQR-based explosive detection systems has been designed and built using the proposed scheme with 1 kW possible maximum output power and 10 MHz maximum operating frequency. Test results show that the presented PA achieves more than 60% measured efficiency within a highly compact volume while sustaining fast start and stop of excitation signals in the order of microseconds.

  3. Effect of Geomagnetism on 101Ru Nuclear Quadrupole Resonance Measurements of CeRu2

    NASA Astrophysics Data System (ADS)

    Manago, Masahiro; Ishida, Kenji; Matsuda, Tatsuma D.; ?nuki, Yoshichika

    2015-11-01

    We performed 101Ru nuclear quadrupole resonance (NQR) measurements on the s-wave superconductor CeRu2 and found oscillatory behavior in the spin-echo amplitude at the | 1/2> \\leftrightarrow | 3/2> transitions but not at the | 3/2> \\leftrightarrow | 5/2> transitions. The modulation disappears in the superconducting state or in a magnetic shield, which implies a geomagnetic field effect. Our results indicate that the NQR spin-echo decay curve at the | 1/2> \\leftrightarrow | 3/2> transitions is sensitive to a weak magnetic field.

  4. A versatile computer-controlled pulsed nuclear quadrupole resonance spectrometer

    NASA Astrophysics Data System (ADS)

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

    1999-12-01

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

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

    NASA Astrophysics Data System (ADS)

    Seliger, J.; Žagar, V.

    2008-07-01

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

  6. A Computer-controlled, Fully Automatic NMR/NQR Double Resonance Spectrometer

    NASA Astrophysics Data System (ADS)

    Zhenye, Feng; Lcken, Edwin A. C.; Diolot, Jacques

    1992-02-01

    A completely automatic computer-controlled NMR/NQR double resonance spectrometer is described. It features automatic tuning of the low, variable frequency power amplifier, thus permitting untended use over long periods, with high sensitivity and signal reproducibility. The sample is transferred between the low-frequency, zero-field region and the high-field region using compressed air and the possibility of switching on a field of several tens of gauss during the transfer of the sample is also included

  7. An analytical method for estimating the {sup 14}N nuclear quadrupole resonance parameters of organic compounds with complex free induction decays for radiation effects studies

    SciTech Connect

    Iselin, L.H.

    1992-12-31

    The use of {sup 14}N nuclear quadrupole resonance (NQR) as a radiation dosimetry tool has only recently been explored. An analytical method for analyzing {sup 14}N NQR complex free induction decays is presented with the background necessary to conduct pulsed NQR experiments. The {sup 14}N NQR energy levels and possible transitions are derived in step-by-step detail. The components of a pulsed NQR spectrometer are discussed along with the experimental techniques for conducting radiation effects experiments using the spectrometer. Three data analysis techniques -- the power spectral density Fourier transform, state space singular value decomposition (HSVD), and nonlinear curve fitting (using the downhill simplex method of global optimization and the Levenberg-Marquart method) -- are explained. These three techniques are integrated into an analytical method which uses these numerical techniques in this order to determine the physical NQR parameters. Sample data sets of urea and guanidine sulfate data are used to demonstrate how these methods can be employed to analyze both simple and complex free induction decays. By determining baseline values for biologically significant organics, radiation effects on the NQR parameters can be studied to provide a link between current radiation dosimetry techniques and the biological effects of radiation.

  8. Zeeman shift--a tool for assignment of 14N NQR lines of nonequivalent 14N atoms in powder samples.

    PubMed

    Luznik, J; Jazbinsek, V; Pirnat, J; Seliger, J; Trontelj, Z

    2011-09-01

    The use of Zeeman perturbed 14N nuclear quadrupole resonance (NQR) to determine the ?+ and ?-14N lines in polycrystalline samples with several nonequivalent nitrogen atoms was investigated. The 14N NQR line shift due to a weak external Zeeman magnetic field was calculated, assuming isotropic distribution of EFG tensor directions. We calculated the broad line distribution of the ?+ and ?- line shifts and experimentally confirmed the calculated Zeeman field dependence of singularities (NQR peaks) in cyclotrimethylenetrinitramine (RDX) and aminotetrazole monohydrate (ATMH). The calculated and measured frequency shifts agreed well. The proposed measurement method enabled determination of which 14N NQR lines in ATMH belong to ?+ and which to ?- transitions. PMID:21783395

  9. Intensity of NQR lines for integer spins

    NASA Astrophysics Data System (ADS)

    Anferov, V. P.; Beloglazov, G. S.; Grechishkin, V. S.

    1986-12-01

    Because of the publication of contradictory information demonstrating an incorrect approach to the modeling of NQR-NMR frequency-intensity spectra of integral-spin isotopes (for example, boron-10), we study the NQR-NMR double resonance with level crossing (DRLC) in10B-1H,11B-1H,59K-1H and23Na-1H in crystal hydrates of sodium tetraborate (Na2B4O710H2O) and potassium tetraborate (K2B4O74H2O) and the results of the measurements are compared with theoretical calculations. The fact that for a system including three elements-quadrupole (NQR), Zeeman (NMR), and dipole-dipole, which establishes the interaction of the first two- the intensities of the lines in double resonance spectra are determined both by the equations of balance of the populations of the levels of the quadrupole and Zeeman reservoirs and by the probabilities of transitions within each reservoir is taken into account in the calculations. The distortion of the energy levels of the NQR subsystem by the magnetic field in the process of level crossing with the NMR subsystem is taken into account.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

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

    PubMed

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

    2005-07-14

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

  12. Nuclear quadrupole relaxation in chlorates

    NASA Astrophysics Data System (ADS)

    Kasprzak, J.; Pietrzak, J.

    Sodium, barium and silver chlorates have been subjected to NQR investigations, Measurements of the 35Cl pure quadrupole resonance frequency and relaxation times were carried out in the temperature range from 290 K to temperatures where the NQR signal vanishes. It was found, that temperature dependence of the T 1 indicates some activation processes. The hindered rotation of ClO 3 groups and the water diffusion are playing an essential role in the description of phenomena occuring in these crystals.

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

    NASA Astrophysics Data System (ADS)

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

    2013-06-01

    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.

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

    PubMed

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

    2011-04-01

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

  15. Local electric state of noncentrosymmetric superconductor Mo3Al2C revealed by Mo NQR and NMR experiments

    NASA Astrophysics Data System (ADS)

    Ihara, Y.; Kimura, Y.; Kumagai, K.; Bauer, E.; Rogl, G.; Rogl, P.

    2012-12-01

    Mo nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements were performed on a noncentrosymmetric superconductor Mo3Al2C to investigate the local electronic state at Mo nuclei, which carries the electrons responsible for superconductivity. The NQR frequency, which is linked to the electric field gradient at Mo site, was determined from 95Mo NMR spectrum and the result was verified by the independent 97Mo NQR measurement. The experimentally obtained value is compared to the result of a point charge calculation to extract the EFG induced by conduction electrons and reveal the local electronic state.

  16. WURST-QCPMG sequence and "spin-lock" in 14N nuclear quadrupole resonance

    NASA Astrophysics Data System (ADS)

    Gregorovi?, Alan; Apih, Toma

    2013-08-01

    14N nuclear quadrupole resonance (NQR) is a promising method for the analysis of pharmaceuticals or for the detection of nitrogen based illicit compounds, but so far, the technique is still not widely used, mostly due to the very low sensitivity. This problem is already acute in the preliminary NQR stage, when a compound is being examined for the first time and the NQR frequencies are being searched for, by scanning a wide frequency range step-by-step. In the present work, we experimentally show how to increase the efficiency of this initial stage by using a combination of a wideband excitation achieved with frequency swept pulses (WURST) and a "spin-lock" state obtained with a quadrupolar-CPMG (QCPMG) sequence. In the first part we show that WURST pulses provide a much larger excitation bandwidth compared to common rectangular pulses. This increased bandwidth allows to increase the frequency step and reduces the total number of steps in a scanning stage. In the second part we show that the "spin-lock" decay time T2eff obtained with the WURST-QCPMG combination is practically identical with the T2eff obtained with the most common "spin-lock" sequence, the SLSE, despite a very different nature and length of excitation pulses. This allows for a substantial S/N increase through echo averaging in every individual step and really allows to exploit all the advantages of the wider excitation in the NQR frequency scanning stage. Our experimental results were obtained on a sample of trinitrotoluene, but identical behavior is expected for all compounds where a "spin-lock" state can be created.

  17. Radio frequency quadrupole resonator for linear accelerator

    DOEpatents

    Moretti, Alfred

    1985-01-01

    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.

  18. Zero-field splittings of NQR spectra for bismuth(III) oxy compounds revealed by quadrupole spin echo envelopes

    NASA Astrophysics Data System (ADS)

    Kravchenko, E. A.; Orlov, V. G.; Morgunov, V. G.; Shlykov, M. P.

    2007-11-01

    Local magnetic fields up to 250 G were earlier found by measuring the NQI parameters in bismuth(III) oxy compounds conventionally considered as diamagnets, a strong increase in the 209Bi line intensities being observed in external magnetic fields. An approach based on registration of the quadrupole spin-echo envelopes enabled to reveal small (within an inhomogeneous line broadening) splittings in some other compounds of this type. The modeling of time dependence of the quadrupole spin echo amplitude indicated that modulations of the spin echo envelope in BaBiO2Cl and Bi3B5O12 resulted from weak (?5 G) local magnetic fields. By using this approach, it was found that an increase in the 209Bi resonance intensity in external magnetic fields is related to an influence of the fields on the nuclear spin-spin relaxation rate for the appropriate compounds.

  19. Zero-field splittings of NQR spectra for bismuth(III) oxy compounds revealed by quadrupole spin echo envelopes

    NASA Astrophysics Data System (ADS)

    Kravchenko, E. A.; Orlov, V. G.; Morgunov, V. G.; Shlykov, M. P.

    Local magnetic fields up to 250 G were earlier found by measuring the NQI parameters in bismuth(III) oxy compounds conventionally considered as diamagnets, a strong increase in the 209Bi line intensities being observed in external magnetic fields. An approach based on registration of the quadrupole spin-echo envelopes enabled to reveal small (within an inhomogeneous line broadening) splittings in some other compounds of this type. The modeling of time dependence of the quadrupole spin echo amplitude indicated that modulations of the spin echo envelope in BaBi02Cl and Bi3B5012 resulted from weak (?5 G) local magnetic fields. By using this approach, it was found that an increase in the 209Bi resonance intensity in external magnetic fields is related to an influence of the fields on the nuclear spin-spin relaxation rate for the appropriate compounds.

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

    SciTech Connect

    Iselin, L.H.

    1995-12-01

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

  1. NQR studies on 2,5-dichlorophenol

    NASA Astrophysics Data System (ADS)

    Kasturi, Alapati; Venkatacharyulu, P.; Premaswarup, D.

    1990-11-01

    Nuclear quadrupole resonance (NQR) Zeeman effect studies were carried out on cylindrical single crystals of 2,5-dichlorophenol, using the two 35Cl-NQR frequencies. A self-quenched superregenerative NQR spectrometer was used, and the spectra were analysed ot obtain information on the nature of the crystalline unit cell. An analysis of the experimental data reveals that: (1) the results are in good agreement with the structural reports of Bavoux and Perrin; (2) the crystal unequivocally belongs to the monoclinic system; (3) there are two crystallographically equivalent but physically inequivalent directions for the principal field gradient axes for both the low- and high-frequency resonance lines; (4) as the number of physically inequivalent directions for each of the two resonance lines is two, the minimum number of molecules per unit cell is two; (5) the b axis (90°,90°) is identified as the symmetry axis; (6) the growth axis is slightly inclined to the c axis; (7) the asymmetry parameters obtained for the loci corresponding to the low-frequency line, which is hydrogen bonded, are greater than those for the high-frequency line, which is nonhydrogen bonded; (8) the double-bond character is greater for the hydrogen-bonded chlorine than for the non-hydrogen-bonded chlorine; (9) the ratios of the various bond characters estimated for both the low- and high-frequency resonance lines are 69:24:7 and 74:24:2.

  2. 14N NQR and relaxation in ammonium nitrate

    NASA Astrophysics Data System (ADS)

    Stephenson, David

    2015-04-01

    The complete 14N nuclear quadrupole resonance (NQR) spectrum of ammonium nitrate is presented recorded using two double resonance techniques - double contact cross relaxation and zero field NQR. The spectra gave the quadrupole coupling constant (Qcc) and asymmetry parameter ( ?) values for the nitro of 611 kHz, 0.229 and that for the ammonium nitrogen of 242 kHz, 0.835. The three relaxation transition probabilities have been determined for both the nitro and ammonium nitrogen atoms. The bi-exponential relaxation times (T 1) were measured at 295 K. The values for nitro are 16.9 s and 10.5 s and that of the ammonium are 23.0 s and 16.4 s.

  3. Nuclear quadrupole resonance studies in semi-metallic structures

    NASA Technical Reports Server (NTRS)

    Murty, A. N.

    1974-01-01

    Both experimental and theoretical studies are presented on spectrum analysis of nuclear quadrupole resonance of antimony and arsenic tellurides. Numerical solutions for secular equations of the quadrupole interaction energy are also discussed.

  4. Explosives detection with quadrupole resonance analysis

    NASA Astrophysics Data System (ADS)

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

    1997-02-01

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

  5. Jun2006 Years of Nmr/nqr Experiments in Solid Electrolytes

    NASA Astrophysics Data System (ADS)

    Brinkmann, Detlef

    2006-06-01

    Nuclear Magnetic Resonance (NMR) and Nuclear Quadrupole Resonance (NQR) experiments in solid electrolytes started around 1975 when a new interest arose in solids with high ionic conductivity. The emphasis of this revue is on experiments rather than theoretical issues. We will present typical NMR/NQR studies which demonstrate the power of these techniques to elucidate dynamic and static behavior of these solids at a microscopic level. Because of the overwhelming wealth of results accumulated in the last 30 years, we will be limited to some characteristic examples.

  6. Quadrupole resonance scanner for narcotics detection

    NASA Astrophysics Data System (ADS)

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

    1994-10-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

    In order to investigate physical properties around a ferromagnetic (FM) quantum transition point and a tricritical point (TCP) in the itinerant-electron metamagnetic compound UCoAl, we have performed the 59Co nuclear quadrupole resonance (NQR) measurement for the Fe-substituted U(Co1-xFex)Al(x =0 ,0.5 ,1 ,and2 %) in zero external magnetic field. The Fe concentration dependence of 59Co -NQR spectra at low temperatures indicates that the first-order FM transition occurs at least above x =1 % . The magnetic fluctuations along the c axis detected by the nuclear spin-spin relaxation rate 1 /T2 exhibit an anomaly at Tmax20 K and enhance with increasing x . These results are in good agreement with theoretical predictions and indicate the presence of prominent critical fluctuations at the TCP in this system.

  8. (121,123)Sb and (75)As NMR and NQR investigation of the tetrahedrite (Cu12Sb4S13) - Tennantite (Cu12As4S13) system and other metal arsenides.

    PubMed

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

    2015-10-01

    This work is motivated by the recent developments in online minerals analysis in the mining and minerals processing industry via nuclear quadrupole resonance (NQR). Here we describe a nuclear magnetic resonance (NMR) and NQR study of the minerals tennantite (Cu12As4S13) and tetrahedrite (Cu12 Sb4S13). In the first part NQR lines associated with (75)As in tennantite and (121,123)Sb isotopes in tetrahedrite are reported. The spectroscopy has been restricted to an ambient temperature studies in accord with typical industrial conditions. The second part of this contribution reports nuclear quadrupole-perturbed NMR findings on further, only partially characterised, metal arsenides. The findings enhance the detection capabilities of NQR based analysers for online measurement applications and may aid to control arsenic and antimony concentrations in metal processing stages. PMID:26453410

  9. A computational NQR study on the hydrogen-bonded lattice of cytosine-5-acetic acid.

    PubMed

    Mirzaei, Mahmoud; Hadipour, Nasser L

    2008-04-15

    A computational study at the level of density functional theory (DFT) employing 6-311++G** standard basis set was carried out to evaluate nuclear quadrupole resonance (NQR) spectroscopy parameters in cytosine-5-acetic acid (C5AA). Since the electric field gradient (EFG) tensors are very sensitive to the electrostatic environment at the sites of quadruple nuclei, the most possible interacting molecules with the target one were considered in a five-molecule model system of C5AA using X-ray coordinates transforming. The hydrogen atoms positions were optimized and two model systems of original and H-optimized C5AA were considered in NQR calculations. The calculated EFG tensors at the sites of (17)O, (14)N, and (2)H nuclei were converted to their experimentally measurable parameters, quadrupole coupling constants and asymmetry parameters. The evaluated NQR parameters reveal that the nuclei in original and H-optimized systems contribute to different hydrogen bonding (HB) interaction. The comparison of calculated parameters between optimized isolated gas-phase and crystalline monomer also shows the relationship between the structural deformation and NQR parameters in C5AA. The basis set superposition error (BSSE) calculations yielded no significant errors for employed basis set in the evaluation of NQR parameters. All the calculations were performed by Gaussian 98 package of program. PMID:17926341

  10. Pulsed Bromine-81 Nuclear Quadrupole Resonance Spectroscopy of Brominated Flame Retardants and Associated Polymer Blends.

    NASA Astrophysics Data System (ADS)

    Mrse, Anthony A.; Lee, Youngil; Bryant, Pamela L.; Fronczek, Frank R.; Butler, Leslie G.; Simeral, Larry S.

    1998-03-01

    The dispersion of brominated flame retardants in polymers is monitored with bromine-81 NQR using a pulse NQR spectrometer. The NQR spectrometer consists of a homemade 10-300 MHz single-channel NMR console coupled to a broadly tunable probe. The probe is a loop-gap resonator usable from 220 to 300 MHz, and automatically tuned over any 5 MHz region with a stepping motor and an RF bidirectional coupler. Bromine-81 NQR spectra of several brominated aromatic flame retardants, as pure materials and in polymers, were recorded in the range of 227 to 256 MHz in zero applied magnetic field. Two factors affect the bromine-79/81 NQR transition frequencies in brominated aromatics: electron withdrawing substituents on the ring and intermolecular contacts with other bromine atoms in the crystal structure. An existing model for substituents is updated and a point charge model for the intermolecular contacts is developed. In this study, we exploit the bromine-81 NQR transition frequency dependence on intermolecular contacts to learn how a flame retardant is dispersed in a polymer matrix.

  11. 35Cl NQR frequency and spin lattice relaxation time in 3,4-dichlorophenol as a function of pressure and temperature.

    PubMed

    Ramu, L; Ramesh, K P; Chandramani, R

    2013-01-01

    The pressure dependences of (35)Cl nuclear quadrupole resonance (NQR) frequency, temperature and pressure variation of spin lattice relaxation time (T(1)) were investigated in 3,4-dichlorophenol. T(1) was measured in the temperature range 77-300?K. Furthermore, the NQR frequency and T(1) for these compounds were measured as a function of pressure up to 5?kbar at 300?K. The temperature dependence of the average torsional lifetimes of the molecules and the transition probabilities W(1) and W(2) for the ?m?=?1 and ?m?=?2 transitions were also obtained. A nonlinear variation of NQR frequency with pressure has been observed and the pressure coefficients were observed to be positive. A thermodynamic analysis of the data was carried out to determine the constant volume temperature coefficients of the NQR frequency. An attempt is made to compare the torsional frequencies evaluated from NQR data with those obtained by IR spectra. On selecting the appropriate mode from IR spectra, a good agreement with torsional frequency obtained from NQR data is observed. The previously mentioned approach is a good illustration of the supplementary nature of the data from IR studies, in relation to NQR studies of compounds in solid state. PMID:23161529

  12. Stand-off explosive detection utilizing low power stimulated emission nuclear quadrupole resonance detection and subwavelength focusing wideband super lens

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

    The need for advanced techniques to detect improvised explosive devices (IED) at stand-off distances greater than ten (10) meters has driven AMI Research and Development (AMI) to develop a solution to detect and identify the threat utilizing a forward looking Synthetic Aperture Radar (SAR) combined with our CW radar technology Nuclear Quadrupole Resonance (NQR) detection system. The novel features include a near-field sub-wavelength focusing antenna, a wide band 300 KHz to 300 MHz rapidly scanning CW radar facilitated by a high Q antenna/tuner, and an advanced processor utilizing Rabi transitions where the nucleus oscillates between states under the time dependent incident electromagnetic field and alternately absorbs energy from the incident field while emitting coherent energy via stimulated emission. AMI's Sub-wavelength Focusing Wide Band Super Lens uses a Near-Field SAR, making detection possible at distances greater than ten (10) meters. This super lens is capable of operating on the near-field and focusing electromagnetic waves to resolutions beyond the diffraction limit. When applied to the case of a vehicle approaching an explosive hazard the methodologies of synthetic aperture radar is fused with the array based super resolution and the NQR data processing detecting the explosive hazard.

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

    NASA Astrophysics Data System (ADS)

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

    2013-02-01

    We report the 121/123Sb-NMR/nuclear quadrupole resonance (NQR) measurements on the superconductor BaTi2Sb2O with a two-dimensional Ti2O square-net layer formed with Ti3+ (3d1). NQR measurements revealed that the in-plane four-fold symmetry is broken at the Sb site below TA40 K, without an internal field appearing at the Sb site. These exclude a spin-density wave (SDW)/ charge density wave (CDW) ordering with incommensurate correlations, but can be understood with the commensurate CDW ordering at TA. The spin-lattice relaxation rate 1/T1, measured at the four-fold symmetry breaking site, decreases below superconducting (SC) transition temperature Tc, indicative of the microscopic coexistence of superconductivity and the CDW/SDW phase below TA. Furthermore, 1/T1 of 121Sb-NQR shows a coherence peak just below Tc and decreases exponentially at low temperatures. These results are in sharp contrast with those in cuprate and iron-based superconductors, and strongly suggest that its SC symmetry is classified to an ordinary s-wave state.

  14. Application of a dc SQUID to rf amplification: NQR

    SciTech Connect

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

    1985-05-01

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

  15. The (14)N quadrupole coupling in hexamethylene triperoxide diamine (HMTD).

    PubMed

    Persons, John; Harbison, Gerard S

    2007-11-01

    Using high-field NMR, we have determined the magnitude of the nuclear quadrupole interaction in hexamethylene triperoxide diamine (HMTD), the explosive allegedly used in the London bombings of July 2005. The experimental quadrupolar coupling constant, 5.334 MHz, is in good agreement with quantum chemical calculations. The predicted single zero-field transition frequency should lie in a relatively empty part of the (14)N nuclear quadrupole resonance (NQR) spectrum; the spin relaxation rate is reasonably fast. PMID:17924359

  16. Radio-frequency quadrupole resonator for linear accelerator

    DOEpatents

    Moretti, A.

    1982-10-19

    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.

  17. Nondestructive testing of adhesive bonds by nuclear quadrupole resonance method

    NASA Technical Reports Server (NTRS)

    Hewitt, R. R.

    1971-01-01

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

  18. Ru-NQR studies on filled skutterudite compounds RRu4P12 (R=La,Nd,Sm)

    NASA Astrophysics Data System (ADS)

    Masaki, S.; Mito, T.; Takemura, M.; Wada, S.; Harima, H.; Kikuchi, D.; Sato, H.; Sugawara, H.; Takeda, N.; Zheng, G.-q.

    2008-04-01

    We report nuclear quadrupole resonance (NQR) studies on Ru-sites of filled skutterudite compounds RRu4P12 (R=La,Nd,Sm) in zero magnetic field. For NdRu4P12, the Ru101-NQR signal disappears below TC=1.6 K, which is indicative of the transformation into the ferromagnetically ordered ground state. For SmRu4P12, a single Ru101-NQR line splits into two lines below the metal-insulator transition temperature TMI=16.5 K with the intensity ratio of 3:1. This result gives evidence that there are two inequivalent Ru-sites with different electric field gradient. The intensity ratio leads to a conclusion that the symmetry is lowered below TMI from a cubic Im3bar space group to a trigonal R3bar one.

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

    SciTech Connect

    Jayakody, J.R.P.

    1993-12-31

    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.

  20. Mixed-radiation-field dosimetry utilizing Nuclear Quadrupole Resonance

    SciTech Connect

    Hintenlang, D.E.; Jamil, K.; Iselin, L.H.

    1992-01-01

    Radiation effects on urea, thiourea, guanidine carbonate and guanine sulfate were evaluated for both photon and neutron irradiations. Hydration of these materials typically provides a greatly increased sensitivity to both forms of radiation exposure, although not all materials lend themselves to this treatment without changing the chemical structure of the compound. Urea was found to be the most stable hydrated compound and provides the best sensitivity for quantifying radiation effects using NQR techniques. Urea permits a straight-forward quantification of each of the important parameters of the observed NQR signal, the FID. Several advanced data analysis methods were developed to assist in quantifying NQR spectra, both from urea and materials having more complex molecular structures, such as thiourea and guanidine sulfate. Unfortunately, these analysis techniques are frequently quite time consuming for the complex NQR spectra that result from some of these materials. The simpler analysis afforded by urea has therefore made it the prime candidate for an NQR dosimetry material. The moderate sensitivity of hydrated urea to photon irradiation does not permit this material to achieve the levels of performance required for a personnel dosimeter. It does, however, demonstrate acceptable sensitivity over dose ranges where it could provide a good biological dosimeter for several areas of radiation processing. The demonstrated photon sensitivity could permit hydrated urea to be used in applications such as food irradiation dosimetry. This material also exhibits a good sensitivity to neutron irradiation. The precise correlation between neutron exposure and the parameters of the resulting NQR spectra are currently being developed.

  1. 75As-NQR study of the hybridization gap semiconductor CeOs4As12

    NASA Astrophysics Data System (ADS)

    Yogi, M.; Higa, N.; Niki, H.; Kawata, T.; Sekine, C.

    2016-02-01

    We performed an 75As nuclear quadrupole resonance (NQR) measurement on CeOs4As12. The 75As-NQR spectrum shape demonstrates that the Ce-site filling fraction of our high-pressure synthesized sample is close to unity. A presence of the c — f hybridization gap is confirmed from the temperature dependence of the nuclear spin-lattice relaxation rate 1/T1. An increase of 1/T1 below ∼3 K indicates a development of the spin fluctuations. The 1/T1 for CeOs4As12 shows similar behavior as that for CeOs4Sb12 with different magnitude of the c — f hybridization gap. An absence of phase transition in CeOs4As12 may be caused by the increase of the c — f hybridization, which increases the gap magnitude and reduces the residual density of state inside the gap.

  2. Measurement of temperature and temperature gradient in millimeter samples by chlorine NQR

    NASA Astrophysics Data System (ADS)

    Lunik, Janko; Pirnat, Janez; Trontelj, Zvonko

    2009-09-01

    A mini-thermometer based on the 35Cl nuclear quadrupole resonance (NQR) frequency temperature dependence in the chlorates KClO3 and NaClO3 was built and successfully tested by measuring temperature and temperature gradient at 77 K and higher in about 100 mm3 active volume of a mini Joule-Thomson refrigerator. In the design of the tank-circuit coil, an array of small coils connected in series enabled us (a) to achieve a suitable ratio of inductance to capacity in the NQR spectrometer input tank circuit, (b) to use a single crystal of KClO3 or NaClO3 (of 1-2 mm3 size) in one coil as a mini-thermometer with a resolution of 0.03 K and (c) to construct a system for measuring temperature gradients when the spatial coordinates of each chlorate single crystal within an individual coil are known.

  3. Effect of a weak static magnetic field on nitrogen-14 quadrupole resonance in the case of an axially symmetric electric field gradient tensor.

    PubMed

    Guendouz, Laous; Aissani, Sarra; March, Jean-Franois; Retournard, Alain; Marande, Pierre-Louis; Canet, Daniel

    2013-01-01

    The application of a weak static B0 magnetic field (less than 1 mT) may produce a well-defined splitting of the (14)N Quadrupole Resonance line when the electric field gradient tensor at the nitrogen nucleus level is of axial symmetry. It is theoretically shown and experimentally confirmed that the actual splitting (when it exists) as well as the line-shape and the signal intensity depends on three factors: (i) the amplitude of B0, (ii) the amplitude and pulse duration of the radio-frequency field, B1, used for detecting the NQR signal, and (iii) the relative orientation of B0 and B1. For instance, when B0 is parallel to B1 and regardless of the B0 value, the signal intensity is three times larger than when B0 is perpendicular to B1. This point is of some importance in practice since NQR measurements are almost always performed in the earth field. Moreover, in the course of this study, it has been recognized that important pieces of information regarding line-shape are contained in data points at the beginning of the free induction decay (fid) which, in practice, are eliminated for avoiding spurious signals due to probe ringing. It has been found that these data points can generally be retrieved by linear prediction (LP) procedures. As a further LP benefit, the signal intensity loss (by about a factor of three) is regained. PMID:24183810

  4. 93Nb- and 27Al-NMR/NQR studies of the praseodymium based PrNb2Al20

    NASA Astrophysics Data System (ADS)

    Kubo, Tetsuro; Kotegawa, Hisashi; Tou, Hideki; Higashinaka, Ryuji; Nakama, Akihiro; Aoki, Yuji; Sato, Hideyuki

    2015-03-01

    We report a study of 93Nb- and 27Al-nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) in a praseodymium based compound PrNb2Al20. The observed NMR line at around 3 T and 30 K shows a superposition of typical powder patterns of one Nb signal and at least two Al signals. 93Nb-NMR line could be reproduced by using the previously reported NQR frequency ?Q ? 1.8MHz and asymmetry parameter ? ? 0 [Kubo T et al 2014 JPS Conf. Proc. 3 012031]. From 27Al-NMR/NQR, NQR parameters are obtained to be ?Q,A ? 1.53 MHz, and ?A ? 0.20 for the site A, and ?Q,B ? 2.28 MHz, and ?B ? 0.17 for the site B. By comparing this result with the previous 27Al-NMR study of PrT2Al20 (T = Ti, V) [Tokunaga Y et al 2013 Phys. Rev. B 88 085124], these two Al site are assigned to the two of three crystallographycally inequivalent Al sites.

  5. Low-Frequency NMR and Nqr with a DC SQUID Amplifier

    NASA Astrophysics Data System (ADS)

    Fan, Nong-Qiang

    A sensitive Fourier-transform spectrometer based on a dc SQUID (Superconducting QUantum Interference Device) has been developed for the direct detection of nuclear magnetic resonance (NMR) in zero applied magnetic field and pure nuclear quadrupole resonance (NQR) at low frequencies. The motivation to detect zero field NMR and NQR is to provide a new high resolution spectroscopy technique at frequencies below 200 kHz to study ultra-weak interactions in chemicals and materials. By comparing the sensitivity of a SQUID amplifier with that of a conventional semiconductor amplifier, it is shown that a SQUID amplifier is essential for the direct detection of low frequency resonant signals. The spectrometer has a frequency response extending from about 10 to 200 kHz, and a recovery time (after the magnetic pulse is removed) of about 50 mus. The spectrometer is used to detect NMR spectra from Pt and Cu metal powders in a magnetic field of 6 mtesla, and NQR spectra from ^2D in a tunneling methyl group and ^{14}N in rm NH_4ClO_4. Finally, the zero field NMR spectrum from a quantum tunneling methyl group is calculated.

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

    NASA Technical Reports Server (NTRS)

    Murty, A. N.

    1978-01-01

    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.

  7. Kinetic approach to the damping of giant quadrupole resonances

    SciTech Connect

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

    1990-09-01

    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.

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

    NASA Astrophysics Data System (ADS)

    Jayakody, Jayakody R. Pemadasa

    1993-01-01

    The behavior of induction signals during steady -state pulse irradiation in ^{14} N NQR was investigated experimentally. Because Strong Off-resonance Comb (SORC) signals recur as long as the pulsing continues, very efficient signal-averaging can result. The dependence of these steady-state SORC signals on pulse parameters and on frequency offset are presented, together with a discussion of the applicability of the method. Also as part of the NQR work, Cocaine base has been detected using conventional NQR techniques. The experimental results show that SORC detection can be of sufficient sensitivity to form the basis of narcotics screening devices for both mail and airline baggage. A new NMR technique, to obtain the correlation time of the random thermal motion of a polymer at temperatures near the glass transition has been introduced. The temperature dependence is a result of thermal motion. For slow-motion of a polymer chain near the glass transition, the CSA parameter begins to decrease. This motional narrowing can be interpreted to yield the correlation time of the thermal motion. In this work Nitrocellulose isotopically highly enriched with ^{15}N was studied at four different temperatures between 27^ circ and 120^circ Celsius and the correlation times for polymer backbone motions were obtained. Nafion films containing, water (D_2 O and H_2^{17}O) and methanol (CH_3OD, CH _3^{17}OH), have been studied using Deuteron and Oxygen-17 NMR spectroscopy. Glassy behavior of the water domains at low temperature is evidenced by the specific nature of the ^2H NMR lineshapes. Activation energies extracted from ^2H spin-lattice relaxation data on the high temperature side of the T_1 minimum exhibit a steady increase with increasing water content. In spite of a high degree of molecular mobility, angular-dependent spectra of both unstretched and stretched samples reflect considerable anisotropy of the host polymer. Activation volumes corresponding to a specific dynamical process were obtained from measurements of spin-lattice relaxation vs. pressure. From the NMR measurements of Nafion films containing methanol, it was found that the molecular motion is much more rapid than the molecular motion of water in Nafion membranes.

  9. Absence of Magnetic Dipolar Phase Transition and Evolution of Low-Energy Excitations in PrNb2Al20 with Crystal Electric Field ?3 Ground State: Evidence from 93Nb-NQR Studies

    NASA Astrophysics Data System (ADS)

    Kubo, Tetsuro; Kotegawa, Hisashi; Tou, Hideki; Higashinaka, Ryuji; Nakama, Akihiro; Aoki, Yuji; Sato, Hideyuki

    2015-07-01

    We report measurements of bulk magnetic susceptibility and 93Nb nuclear quadrupole resonance (NQR) in the Pr-based caged compound PrNb2Al20. By analyzing the magnetic susceptibility and magnetization, the crystal electric field (CEF) level scheme of PrNb2Al20 is determined to be ?3(0 K)-?4(21.32 K)-?5(43.98 K)-?1(51.16 K) within the framework of the localized 4f electron picture. The 93Nb-NQR spectra exhibit neither spectral broadening nor spectral shift upon cooling down to 75 mK. The 93Nb-NQR spin-lattice relaxation rate 1/T1 at 5 K depends on the frequency and remains almost constant below 5 K. The frequency dependence of 1/T1 is attributed to the magnetic fluctuation due to the hyperfine-enhanced 141Pr nuclear moment inherent in the nonmagnetic ?3 CEF ground state. The present NQR results provide evidence that no symmetry-breaking magnetic dipole order occurs down to 75 mK. Also, considering an invariant form of the quadrupole and octupole couplings between a 93Nb nucleus and Pr 4f electrons, Pr 4f quadrupoles and an octupole can couple with a 93Nb nuclear quadrupole moment and nuclear spin, respectively. Together with the results of bulk measurements, the present NQR results suggest that the possibility of a static quadrupole or octupole ordering can be excluded down to 100 mK. At low temperatures below 500 mK, however, the nuclear spin-echo decay rate gradually increases and the decay curve changes from Gaussian decay to Lorentzian decay, suggesting the evolution of a low-energy excitation.

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

    PubMed

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

    2014-09-22

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

  11. NQR experiments on Sc-Y alloys at very low temperatures. [Absolute thermometry below 500[mu]K

    SciTech Connect

    Pollack, L.; Smith, E.N.; Richardson, R.C. )

    1992-10-01

    The authors performed Nuclear Quadrupole Resonance (NQR) experiments on an alloy of scandium and yttrium. They find that the characteristic resonance frequencies in zero external field are 50% larger than in pure scandium. This increase in frequency makes the Sc-Y alloy a better candidate for absolute thermometry below 500 [mu]K. However, the spin-lattice relaxation time of this alloy is more than an order of magnitude longer than in the pure scandium. In addition, an abrupt increase in the Korringa constant was observed for temperatures below 5mK.

  12. Pulsed Spin Locking in Spin-1 NQR: Broadening Mechanisms

    NASA Astrophysics Data System (ADS)

    Malone, Michael W.

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

  13. A Pulsed Spectrometer Designed for Feedback NQR

    NASA Astrophysics Data System (ADS)

    Schiano, J. L.; Ginsberg, M. D.

    2000-02-01

    A pulsed NQR spectrometer specifically designed to facilitate real-time tuning of pulse sequence parameters is described. A modular approach based on the interconnection of several rack-mounted blocks provides easy access to all spectrometer signals and simplifies the task of modifying the spectrometer design. We also present experimental data that demonstrates the ability of the spectrometer to increase the signal to noise ratio of NQR measurements by automatically adjusting the pulse width in the strong off-resonant comb pulse sequence.

  14. Wireless power transfer based on magnetic quadrupole coupling in dielectric resonators

    NASA Astrophysics Data System (ADS)

    Song, Mingzhao; Iorsh, Ivan; Kapitanova, Polina; Nenasheva, Elizaveta; Belov, Pavel

    2016-01-01

    We numerically investigate a magnetic resonant wireless power transfer system based on high refractive index dielectric resonators. We propose to operate at magnetic quadrupole mode of the resonators to enlarge the efficiency due to minimization of ohmic and radiation losses. Numerical estimation predicts the 80% efficiency of the wireless power transfer (WPT) system operating at quadrupole mode at 300 MHz. Moreover, the system operating at magnetic quadrupole mode is capable of transferring power with 70% efficiency when the receiver rotates 90°. We verify the simulated results by experimental investigation of the WPT system based on microwave ceramic resonators (ɛ = 80 and tanδ = 10-4).

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

    PubMed

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

    2012-03-01

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

  16. New perspectives in the PAW/GIPAW approach: J(P-O-Si) coupling constants, antisymmetric parts of shift tensors and NQR predictions.

    PubMed

    Bonhomme, Christian; Gervais, Christel; Coelho, Cristina; Pourpoint, Frédérique; Azaïs, Thierry; Bonhomme-Coury, Laure; Babonneau, Florence; Jacob, Guy; Ferrari, Maude; Canet, Daniel; Yates, Jonathan R; Pickard, Chris J; Joyce, Siân A; Mauri, Francesco; Massiot, Dominique

    2010-12-01

    In 2001, Pickard and Mauri implemented the gauge including projected augmented wave (GIPAW) protocol for first-principles calculations of NMR parameters using periodic boundary conditions (chemical shift anisotropy and electric field gradient tensors). In this paper, three potentially interesting perspectives in connection with PAW/GIPAW in solid-state NMR and pure nuclear quadrupole resonance (NQR) are presented: (i) the calculation of J coupling tensors in inorganic solids; (ii) the calculation of the antisymmetric part of chemical shift tensors and (iii) the prediction of (14)N and (35)Cl pure NQR resonances including dynamics. We believe that these topics should open new insights in the combination of GIPAW, NMR/NQR crystallography, temperature effects and dynamics. Points (i), (ii) and (iii) will be illustrated by selected examples: (i) chemical shift tensors and heteronuclear (2)J(P-O-Si) coupling constants in the case of silicophosphates and calcium phosphates [Si(5)O(PO(4))(6), SiP(2)O(7) polymorphs and α-Ca(PO(3))(2)]; (ii) antisymmetric chemical shift tensors in cyclopropene derivatives, C(3)X(4) (X = H, Cl, F) and (iii) (14)N and (35)Cl NQR predictions in the case of RDX (C(3)H(6)N(6)O(6)), β-HMX (C(4)H(8)N(8)O(8)), α-NTO (C(2)H(2)N(4)O(3)) and AlOPCl(6). RDX, β-HMX and α-NTO are explosive compounds. PMID:20589728

  17. Beta-detected NQR in zero field with a low energy beam of 8Li+

    NASA Astrophysics Data System (ADS)

    Salman, Z.; Kiefl, R. F.; Chow, K. H.; MacFarlane, W. A.; Kreitzman, S. R.; Arseneau, D. J.; Daviel, S.; Levy, C. D. P.; Maeno, Y.; Poutissou, R.

    2006-03-01

    Beta-detected nuclear quadrupole resonances ( ?-NQR) in zero field are observed using a beam of low energy highly polarized radioactive Li+8. The resonances were detected in SrTiO 3, Al 2O 3 and Sr 2RuO 4 single crystals by monitoring the beta-decay anisotropy as a function of a small audio frequency magnetic field. The resonances show clearly that Li+8 occupies one site with non-cubic symmetry in SrTiO 3, two in Al 2O 3 and three sites in Sr 2RuO 4. The resonance amplitude and width are surprisingly large compared to the values expected from transitions between the |2>?|1> spin states, indicating a significant mixing between the |m> quadrupolar split levels.

  18. A new dedicated ?-NMR/?-NQR setup for LISE-GANIL

    NASA Astrophysics Data System (ADS)

    De Rydt, M.; Lozeva, R.; Vermeulen, N.; de Oliveira Santos, F.; Grvy, S.; Himpe, P.; Stdel, C.; Thomas, J. C.; Vingerhoets, P.; Neyens, G.

    2009-12-01

    A new ?-NMR/?-NQR setup is developed to study nuclear magnetic dipole moments and electric quadrupole moments at the LISE fragment separator at GANIL. Two key elements make the new design very powerful: the homogeneous magnet and the strong radio-frequency amplifier. The combination of both makes it possible to examine a broad spectrum of magnetic dipole and electric quadrupole moments. Several factors have an influence on the detection efficiency and on the sensitivity of the setup to observe a resonant change in the ?-asymmetry: the thickness and the tilting angle of the implantation crystal, the material in the vacuum chamber, the applied magnetic field and the Q?-value of the decaying nuclei. A detailed study of these effects is made using a dedicated GEANT4 Monte Carlo simulation code.

  19. Studies of the electronic structure and biological activity of chosen 1,4-benzodiazepines by 35Cl NQR spectroscopy and DFT calculations

    NASA Astrophysics Data System (ADS)

    Bronisz, K.; Ostafin, M.; Poleshchuk, O. Kh.; Mielcarek, J.; Nogaj, B.

    2006-11-01

    Selected derivatives of 1,4-benzodiazepine: lorazepam, lormetazepam, oxazepam and temazepam, used as active substances in anxiolytic drugs, have been studied by 35Cl NQR method in order to find the correlation between electronic structure and biological activity. The 35Cl NQR resonance frequencies ( νQ) measured at 77 K have been correlated with the following parameters characterising their biological activity: biological half-life period ( t0.5), affinity to benzodiazepine receptor (IC 50) and mean dose equivalent. The results of experimental study of some benzodiazepine derivatives by nuclear quadrupole resonance of 35Cl nuclei are compared with theoretical results based on DFT calculations which were carried out by means of Gaussian'98 W software.

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  1. High-Efficiency Resonant Cavity Quadrupole Moment Monitor

    SciTech Connect

    Barov, N.; Kim, J. S.; Nantista, C. D.; Miller, R. H.

    2006-11-27

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

  2. Polymorphism and disorder in natural active ingredients. Low and high-temperature phases of anhydrous caffeine: Spectroscopic ((1)H-(14)N NMR-NQR/(14)N NQR) and solid-state computational modelling (DFT/QTAIM/RDS) study.

    PubMed

    Seliger, Janez; Žagar, Veselko; Apih, Tomaž; Gregorovič, Alan; Latosińska, Magdalena; Olejniczak, Grzegorz Andrzej; Latosińska, Jolanta Natalia

    2016-03-31

    The polymorphism of anhydrous caffeine (1,3,7-trimethylxanthine; 1,3,7-trimethyl-1H-purine-2,6-(3H,7H)-dione) has been studied by (1)H-(14)N NMR-NQR (Nuclear Magnetic Resonance-Nuclear Quadrupole Resonance) double resonance and pure (14)N NQR (Nuclear Quadrupole Resonance) followed by computational modelling (Density Functional Theory, supplemented Quantum Theory of Atoms in Molecules with Reduced Density Gradient) in solid state. For two stable (phase II, form β) and metastable (phase I, form α) polymorphs the complete NQR spectra consisting of 12 lines were recorded. The assignment of signals detected in experiment to particular nitrogen sites was verified with the help of DFT. The shifts of the NQR frequencies, quadrupole coupling constants and asymmetry parameters at each nitrogen site due to polymorphic transition were evaluated. The strongest shifts were observed at N(3) site, while the smallest at N(9) site. The commercial pharmaceutical sample was found to contain approximately 20-25% of phase I and 75-80% of phase II. The orientational disorder in phase II with a local molecular arrangement mimics that in phase I. Substantial differences in the intermolecular interaction phases I and II of caffeine were analysed using computational (DFT/QTAIM/RDS) approach. The analysis of local environment of each nitrogen nucleus permitted drawing some conclusions on the topology of interactions in both polymorphs. For the most stable orientations in phase I and phase II the maps of the principal component qz of EFG tensor and its asymmetry parameter at each point of the molecular system were calculated and visualized. The relevant maps calculated for both phases I and II indicates small variation in electrostatic potential upon phase change. Small differences between packings in phases slightly disturb the neighbourhood of the N(1) and N(7) nitrogens, thus are meaningless from the biological point of view. The composition of two phases in pharmaceutical material should not be any obstacle, which is relevant from the pharmaceutical industry point of view. PMID:26826282

  3. Two-dimensional exchange 35Cl NQR spectroscopy of hexachloroethane

    NASA Astrophysics Data System (ADS)

    Maćkowiak, Mariusz; Sinyavsky, Nicolay; Bluemich, Bernhard

    2005-05-01

    Two-dimensional exchange 35Cl NQR spectroscopy for studies of the CCl 3-group reorientation processes in hexachloroethane has been applied. It has been demonstrated that 2D NQR exchange spectroscopy is appropriate for quantitative studies of exchange processes in molecular crystals containing quadrupole nuclei. The method is of particular value for the detection of exchange networks in systems with many sites. Thus, detailed information on the exchange pathways within a network of structural isomers in hexachloroethane can be deduced and a proper assignment of the NQR lines can be made. Temperature dependence of the exchange rate was studied. The mixing dynamics by exchange and the expected cross-peak intensities have been derived. The very good agreement of the experimental results with theoretical predictions confirms the validity of the motion model.

  4. High-frequency nuclear quadrupole resonance apparatus for use in pressure cell

    NASA Astrophysics Data System (ADS)

    Iwase, F.; Miyagawa, K.; Kanoda, K.

    2012-06-01

    A high-frequency NMR apparatus for use in pressure cell is described. All components of the resonance circuit are set in the pressure cell. This method makes the resonance frequency much less influenced by large stray capacitance residing at the electrical feedthrough of the pressure cell. With the use of this apparatus, a pressure-induced neutral-ionic phase transition in DMTTF-QBr4 was successfully observed by 79Br nuclear quadrupole resonance, whose resonance frequency is 300 MHz.

  5. Negative coupling and coupling phase dispersion in a silicon quadrupole micro-racetrack resonator.

    PubMed

    Bachman, Daniel; Tsay, Alan; Van, Vien

    2015-07-27

    We report the first experimental study of the effects of coupling phase dispersion on the spectral response of a two-dimensionally coupled quadrupole micro-racetrack resonator. Negative coupling in the system is observed to manifest itself in the sharp stop band transition and deep extinction in the pseudo-elliptic filter response of the quadrupole. The results demonstrate the feasibility of realizing advanced silicon microring devices based on the 2D coupling topology with general complex coupling coefficients. PMID:26367666

  6. Nuclear quadrupole resonance of 14N and 2H in pyrimidines, purines, and their nucleosides

    NASA Astrophysics Data System (ADS)

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

    Using nuclear quadrupole double-resonance techniques, nitrogen-14 and deuterium nuclear quadrupole coupling constants and asymmetry parameters have been measured in uracil, 5-bromouracil, cytosine, adenine, xanthine, hypoxanthine, their nucleosides, 2-aminopyrimidine, and benzimidazole. Zeeman studies and the detection of the simultaneous transitions of neighboring nuclei allowed in many cases a complete assignment of the observed spectral lines to particular 14N and 2D sites.

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

    SciTech Connect

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

    1980-12-01

    A discussion of how stress and strain affect the quantities which can be measured in an NQR experiment shows that, for stresses of the magnitude to be expected at depths up to about 10,000 feet, quadrupole coupling constants will fall in the range of 1 to 10 kHz for both the sodium and chloride ions in NaCl. The most promising system involves pulsed nuclear double resonance detection; and alterative is to observe the quadrupolar splitting of the NMR signal. Choices to be made in the measurement and mapping techniques are discussed. The well-known perturbation of the homogenous stress field in the neighborhood of a borehole is shown to be advantageous from the point of view of obtaining directional information on the stress. Construction and operation of a borehole stress sensor are considered. The NQR technique seems feasible for measuring the magnitude and direction of underground stress with a resolution of about 25 psi, or 2.5% at 1000 psi. Downhole instrumentation suitable for in-situ determinations of stress appears within the state of the art. Additional tasks required on the project are identified.

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

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

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

  9. Design and testing of a low impedance transceiver circuit for nitrogen-14 nuclear quadrupole resonance.

    PubMed

    Sato-Akaba, Hideo

    2014-01-01

    A low impedance transceiver circuit consisting of a transmit-receive switch circuit, a class-D amplifier and a transimpedance amplifier (TIA) was newly designed and tested for a nitrogen-14 NQR. An NQR signal at 1.37MHz from imidazole was successfully observed with the dead time of ~85µs under the high Q transmission (Q~120) and reception (Q~140). The noise performance of the low impedance TIA with an NQR probe was comparable with a commercial low noise 50Ω amplifier (voltage input noise: 0.25 nV/Hz) which was also connected to the probe. The protection voltage for the pre-amplifier using the low impedance transceiver was ~10 times smaller than that for the pre-amplifier using a 50Ω conventional transceiver, which is suitable for NQR remote sensing applications. PMID:25293696

  10. Two-dimensional NQR using ultra-broadband electronics

    NASA Astrophysics Data System (ADS)

    Mandal, S.; Song, Y.-Q.

    2014-03-01

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

  11. Mixed-radiation-field dosimetry utilizing Nuclear Quadrupole Resonance. Final report

    SciTech Connect

    Hintenlang, D.E.; Jamil, K.; Iselin, L.H.

    1992-12-31

    Radiation effects on urea, thiourea, guanidine carbonate and guanine sulfate were evaluated for both photon and neutron irradiations. Hydration of these materials typically provides a greatly increased sensitivity to both forms of radiation exposure, although not all materials lend themselves to this treatment without changing the chemical structure of the compound. Urea was found to be the most stable hydrated compound and provides the best sensitivity for quantifying radiation effects using NQR techniques. Urea permits a straight-forward quantification of each of the important parameters of the observed NQR signal, the FID. Several advanced data analysis methods were developed to assist in quantifying NQR spectra, both from urea and materials having more complex molecular structures, such as thiourea and guanidine sulfate. Unfortunately, these analysis techniques are frequently quite time consuming for the complex NQR spectra that result from some of these materials. The simpler analysis afforded by urea has therefore made it the prime candidate for an NQR dosimetry material. The moderate sensitivity of hydrated urea to photon irradiation does not permit this material to achieve the levels of performance required for a personnel dosimeter. It does, however, demonstrate acceptable sensitivity over dose ranges where it could provide a good biological dosimeter for several areas of radiation processing. The demonstrated photon sensitivity could permit hydrated urea to be used in applications such as food irradiation dosimetry. This material also exhibits a good sensitivity to neutron irradiation. The precise correlation between neutron exposure and the parameters of the resulting NQR spectra are currently being developed.

  12. Ferromagnetic Spin Fluctuation and Unconventional Superconductivity in Rb2Cr3As3 Revealed by 75As NMR and NQR

    NASA Astrophysics Data System (ADS)

    Yang, J.; Tang, Z. T.; Cao, G. H.; Zheng, Guo-qing

    2015-10-01

    We report 75As nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) studies on the superconductor Rb2Cr3As3 with a quasi-one-dimensional crystal structure. Below T 100 K , the spin-lattice relaxation rate (1 /T1 ) divided by temperature, 1 /T1T , increases upon cooling down to Tc=4.8 K , showing a Curie-Weiss-like temperature dependence. The Knight shift also increases with decreasing temperature. These results suggest ferromagnetic spin fluctuation. In the superconducting state, 1 /T1 decreases rapidly below Tc without a Hebel-Slichter peak, and follows a T5 variation below T 3 K , which points to unconventional superconductivity with point nodes in the gap function.

  13. Ferromagnetic Spin Fluctuation and Unconventional Superconductivity in Rb2Cr3As3 Revealed by 75As NMR and NQR.

    PubMed

    Yang, J; Tang, Z T; Cao, G H; Zheng, Guo-Qing

    2015-10-01

    We report (75)As nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) studies on the superconductor Rb(2)Cr(3)As(3) with a quasi-one-dimensional crystal structure. Below T∼100  K, the spin-lattice relaxation rate (1/T(1)) divided by temperature, 1/T(1)T, increases upon cooling down to T(c)=4.8  K, showing a Curie-Weiss-like temperature dependence. The Knight shift also increases with decreasing temperature. These results suggest ferromagnetic spin fluctuation. In the superconducting state, 1/T(1) decreases rapidly below T(c) without a Hebel-Slichter peak, and follows a T(5) variation below T∼3  K, which points to unconventional superconductivity with point nodes in the gap function. PMID:26551818

  14. Nuclear quadrupole interactions and charge localization in HgBa 2CuO 4 + ? with different oxygen content

    NASA Astrophysics Data System (ADS)

    Gippius, A. A.; Antipov, E. V.; Hoffmann, W.; Lders, K.

    1997-02-01

    Variation of the oxygen content ? in HgBa 2CuO 4 + ? (Hg-1201) provides a good opportunity to study the influence of oxygen doping on nuclear quadrupole interactions (NQI) and charge localisation in different regions of the ( Tc- ?) phase diagram. We performed 63,65Cu Nuclear Quadrupole Resonance (NQR) studies on a series of HgBa 2CuO 4 + ? samples with different oxygen content ?. Based on the experimental NQR spectra of the Hg-1201 compounds and the known copper NQR frequency for the undoped Nd 2CuO 4 a phenomenological method is developed to analyze the NQI in high temperature superconductors (HTSC) including both, the on-site electric field gradient (EFG) and the lattice contribution in the EFG. Using this method we estimated the Sternheimer antishielding factor ?? = -16.2 for Cu 2+ and the hole concentration nx2- y2 on the copper 3d x2- y2 orbital. The nx2- y2 value rises monotonously with increasing doping level over the whole Hg-1201 sample series and is the main factor causing the increase of quadrupole frequency vQ. No saturation effect on the copper hole doping process has been found at high oxygen content level.

  15. An 17O nuclear quadrupole resonance study of some carboxylic acids

    NASA Astrophysics Data System (ADS)

    Brosnan, S. G. P.; Edmonds, D. T.; Poplett, I. J. F.

    Using the new technique of doule resonance with coupled multiplets the nuclear quadrupole resonance spectra of 17O, naturally abundant at both the C?O and C?O?H sites in formic acid acrylic acid, fumaric acid, ?-oxalic acid, ? oxalic acid, maleic acid, acetic acid, and substituted acetic acids, were measured. The specimens were frozen solutions or powdered solids. For the C?O?H site fine structure is observed on the spectral lines attributable to magnetic interaction with the neighboring proton. Analysis of the structure gives the sign of the quadrupole coupling constant and also information about the principal axes of the electric field gradient at the 17O nucleus. A simple Townes and Dailey analysis is carried out for the C?O?H site.

  16. Quadrupole moment of XAg/sup m/ determined by level mixing resonance on oriented nuclei

    SciTech Connect

    Berkes, I.; Hajjaji, O.E.; Hlimi, B.; Marest, G.; Coussement, R.; Hardeman, F.; Put, P.; Scheveneels, G.

    1986-01-01

    The quadrupole moment ratio of XAg/sup m/ to ZAg/sup m/ has been determined as Q( XAg/sup m/)/Q( ZAg /sup m/) = 0.960(10) with the level mixing resonance on oriented nuclei technique. Using the previously established electric field gradient of silver in zinc, Q( XAg/sup m/) = 0.98(11) b has been deduced. The results are in agreement with the theoretical predictions.

  17. ¹⁴N Quadrupole Resonance line broadening due to the earth magnetic field, occuring only in the case of an axially symmetric electric field gradient tensor.

    PubMed

    Aissani, Sarra; Guendouz, Laouès; Marande, Pierre-Louis; Canet, Daniel

    2015-01-01

    As demonstrated before, the application of a weak static B0 magnetic field (less than 10 G) may produce definite effects on the ¹⁴N Quadrupole Resonance line when the electric field gradient tensor at the nitrogen nucleus level is of axial symmetry. Here, we address more precisely the problem of the relative orientation of the two magnetic fields (the static field and the radio-frequency field of the pure NQR experiment). For a field of 6G, the evolution of the signal intensity, as a function of this relative orientation, is in very good agreement with the theoretical predictions. There is in particular an intensity loss by a factor of three when going from the parallel configuration to the perpendicular configuration. By contrast, when dealing with a very weak magnetic field (as the earth field, around 0.5 G), this effect drops to ca. 1.5 in the case Hexamethylenetetramine (HMT).This is explained by the fact that the Zeeman shift (due to the very weak magnetic field) becomes comparable to the natural line-width. The latter can therefore be determined by accounting for this competition. Still in the case of HMT, the estimated natural line-width is half the observed line-width. The extra broadening is thus attributed to earth magnetic field. The latter constitutes therefore the main cause of the difference between the natural transverse relaxation time (T₂) and the transverse relaxation time derived from the observed line-width (T₂(⁎)). PMID:25910551

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

    DOEpatents

    Fan, N.Q.; Clarke, J.

    1993-10-19

    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.

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

    DOEpatents

    Fan, Non Q.; Clarke, John

    1993-01-01

    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.

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

    NASA Technical Reports Server (NTRS)

    Borsa, F.; Rigamonti, A.

    1991-01-01

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

  1. Nuclear quadrupole resonance detected at 30 MHz with a dc superconducting quantum interference device

    SciTech Connect

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

    1985-09-15

    A dc superconducting quantum interference device is used as a tuned radio frequency amplifier at liquid helium temperatures to detect pulsed nuclear quadrupole resonance at approx.30 MHz. At a bath temperature of 4.2 K, a total system noise temperature of 6 +- 1 K has been achieved, with a quality factor Q of 2500. A novel Q spoiler, consisting of a series array of Josephson tunnel junctions, reduces the ring-down time of the tuned circuit after each pulse. The minimum number of Bohr magnetons observable from a free precession signal after a single pulse is approx.2 x 10/sup 16/ in a bandwidth of 10 kHz.

  2. NMR and NQR study of the thermodynamically stable quasicrystals

    SciTech Connect

    Shastri, A.

    1995-02-10

    {sup 27}Al and {sup 61,65}Cu NMR measurements are reported for powder samples of stable AlCuFe and AlCuRu icosahedral quasicrystals and their crystalline approximants, and for a AlPdMn single grain quasicrystal. Furthermore, {sup 27}Al NQR spectra at 4.2 K have been observed in the AlCuFe and AlCuRu samples. From the quadrupole perturbed NMR spectra at different magnetic fields, and from the zero field NQR spectra, a wide distribution of local electric field gradient (EFG) tensor components and principal axis system orientations was found at the Al site. A model EFG calculation based on a 1/1 AlCuFe approximant was successful in explaining the observed NQR spectra. It is concluded that the average local gradient is largely determined by the p-electron wave function at the Al site, while the width of the distribution is due to the lattice contribution to the EFG. Comparison of {sup 63}Cu NMR with {sup 27}Al NMR shows that the EFG distribution at the two sites is similar, but that the electronic contribution to the EFG is considerably smaller at the Cu site, in agreement with a more s-type wave function of the conduction electrons.

  3. The pygmy quadrupole resonance and neutron-skin modes in 124Sn

    NASA Astrophysics Data System (ADS)

    Spieker, M.; Tsoneva, N.; Derya, V.; Endres, J.; Savran, D.; Harakeh, M. N.; Harissopulos, S.; Herzberg, R.-D.; Lagoyannis, A.; Lenske, H.; Pietralla, N.; Popescu, L.; Scheck, M.; Schlter, F.; Sonnabend, K.; Stoica, V. I.; Wrtche, H. J.; Zilges, A.

    2016-01-01

    We present an extensive experimental study of the recently predicted pygmy quadrupole resonance (PQR) in Sn isotopes, where complementary probes were used. In this study, (? ,?? ?) and (? ,??) experiments were performed on 124Sn. In both reactions, J? =2+ states below an excitation energy of 5 MeV were populated. The E2 strength integrated over the full transition densities could be extracted from the (? ,??) experiment, while the (? ,?? ?) experiment at the chosen kinematics strongly favors the excitation of surface modes because of the strong ?-particle absorption in the nuclear interior. The excitation of such modes is in accordance with the quadrupole-type oscillation of the neutron skin predicted by a microscopic approach based on self-consistent density functional theory and the quasiparticle-phonon model (QPM). The newly determined ?-decay branching ratios hint at a non-statistical character of the E2 strength, as it has also been recently pointed out for the case of the pygmy dipole resonance (PDR). This allows us to distinguish between PQR-type and multiphonon excitations and, consequently, supports the recent first experimental indications of a PQR in 124Sn.

  4. Quality control and health monitoring of aerospace composites via quadrupole resonance

    NASA Astrophysics Data System (ADS)

    Ward, Catherine; Vierkoetter, Stephanie A.

    2005-05-01

    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 present an extension of this work, applying the QR method to the quality control of composite parts manufactured via pultrusion. In order to use the QR method for quality control of composite parts they must contain a small amount of tiny crystals of a QR active compound. These crystals are embedded in the part during the manufacture by blending it into the uncured resin. The QR active crystals sense any residual strains that may form inside the part during the manufacturing process. The crystals are interrogated via a single-side coil detector head, which transmits radio frequency (RF) pulses into the composite part. The strain-dependent QR response from the crystals is picked up by the same detector head. The results presented in this paper demonstrate that the QR method is very successful at distinguishing composites parts manufactured under optimal conditions from those that were manufactured with a misaligned die or at reduced temperatures. Both QR frequency and line widths were used as a distinguishing parameter.

  5. Suppression of electron correlations in the collapsed tetragonal phase of CaFe2As2 under ambient pressure demonstrated by As75 NMR/NQR measurements

    NASA Astrophysics Data System (ADS)

    Furukawa, Y.; Roy, B.; Ran, S.; Bud'ko, S. L.; Canfield, P. C.

    2014-03-01

    The static and the dynamic spin correlations in the low-temperature collapsed tetragonal and the high-temperature tetragonal phase in CaFe2As2 have been investigated by As75 nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements. Through the temperature (T) dependence of the nuclear spin lattice relaxation rates (1/T1) and the Knight shifts, although stripe-type antiferromagnetic (AFM) spin correlations are realized in the high-temperature tetragonal phase, no trace of the AFM spin correlations can be found in the nonsuperconducting, low-temperature, collapsed tetragonal (cT) phase. Given that there is no magnetic broadening in As75 NMR spectra, together with the T-independent behavior of magnetic susceptibility ? and the T dependence of 1/T1T?, we conclude that Fe spin correlations are completely quenched statically and dynamically in the nonsuperconducting cT phase in CaFe2As2.

  6. Suppression of electron correlations in the collapsed tetragonal phase of CaFe2As2 under ambient pressure demonstrated by As75 NMR/NQR measurements

    SciTech Connect

    Furukawa, Yuji; Roy, Beas; Ran, Sheng; Budko, Sergey L.; Canfield, Paul C.

    2014-03-20

    The static and the dynamic spin correlations in the low-temperature collapsed tetragonal and the high-temperature tetragonal phase in CaFe2As2 have been investigated by As75 nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements. Through the temperature (T) dependence of the nuclear spin lattice relaxation rates (1/T1) and the Knight shifts, although stripe-type antiferromagnetic (AFM) spin correlations are realized in the high-temperature tetragonal phase, no trace of the AFM spin correlations can be found in the nonsuperconducting, low-temperature, collapsed tetragonal (cT) phase. Given that there is no magnetic broadening in As75 NMR spectra, together with the T-independent behavior of magnetic susceptibility ? and the T dependence of 1/T1T?, we conclude that Fe spin correlations are completely quenched statically and dynamically in the nonsuperconducting cT phase in CaFe2As2.

  7. Coexistence of multiple charge-density waves and superconductivity in SrPt2As2 revealed by 75As-NMR /NQR and 195Pt-NMR

    NASA Astrophysics Data System (ADS)

    Kawasaki, Shinji; Tani, Yoshihiko; Mabuchi, Tomosuke; Kudo, Kazutaka; Nishikubo, Yoshihiro; Mitsuoka, Daisuke; Nohara, Minoru; Zheng, Guo-qing

    2015-02-01

    The relationship between charge-density wave (CDW) orders and superconductivity in arsenide superconductor SrPt2As2 with Tc=5.2 K which crystallizes in the CaBe2Ge2 -type structure was studied by 75As nuclear magnetic resonance (NMR) measurements up to 520 K, and 75As nuclear quadrupole resonance (NQR) and 195Pt-NMR measurements down to 1.5 K. At high temperature, 75As-NMR spectrum and nuclear-spin-relaxation rate (1 /T1) have revealed two distinct CDW orders, one realized in the As-Pt-As layer below TCDWAs (1 )=410 K and the other in the Pt-As-Pt layer below TCDWAs (2 )=255 K . The 1 /T1 measured by 75As-NQR shows a clear Hebel-Slichter peak just below Tc and decreases exponentially well below Tc. Concomitantly, 195Pt Knight shift decreases below Tc. Our results indicate that superconductivity in SrPt2As2 is in the spin-singlet state with an s -wave gap and is robust under the two distinct CDW orders in different layers.

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

    NASA Astrophysics Data System (ADS)

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

    2008-02-01

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

  9. Cu NQR study of charge localization in HgBa2CuO4+? with different oxygen content

    NASA Astrophysics Data System (ADS)

    Gippius, A. A.; Antipov, E. V.; Hoffmann, W.; Lders, K.

    1996-02-01

    Variation of the oxygen content ? in HgBa2CuO4+?(1201) provides a good opportunity to study the influence of oxygen doping on nuclear quadrupole interactions (NQI) and charge localization in different regions of (Tc-?) phase diagram. We performed63,65Cu NQR of series HgBa2CuO4+? samples with different oxygen content ?.

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

    SciTech Connect

    Aiba, Hirokazu; Matsuo, Masayuki; Nishizaki, Shigeru; Suzuki, Toru

    2011-02-15

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

  11. A study of transition-metal organometallic complexes combining 35Cl solid-state NMR spectroscopy and 35Cl?NQR spectroscopy and first-principles DFT calculations.

    PubMed

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

    2013-09-01

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

  12. Analytical continuation from bound to resonant states in the Dirac equation with quadrupole-deformed potentials

    NASA Astrophysics Data System (ADS)

    Xu, Xu-Dong; Zhang, Shi-Sheng; Signoracci, A. J.; Smith, M. S.; Li, Z. P.

    2015-08-01

    Background: Resonances with pronounced single-particle characteristics are crucial for quantitative descriptions of exotic nuclei near and beyond the drip lines, and often impact halo formation and nucleon decay processes. Since the majority of nuclei are deformed, the interplay between deformation and orbital structure near threshold can lead to improved descriptions of exotic nuclei. Purpose: Develop a method to study single-particle resonant orbital structure in the Dirac equation with a quadrupole-deformed Woods-Saxon potential. Determine the structure evolution of bound and resonant levels with deformation in this scheme, and examine the impact on halo formation in loosely bound systems, with a focus on the recent halo candidate nucleus 37Mg. Method: Analytical continuation of the coupling constant (ACCC) method is developed on the basis of the Dirac equation with a deformed Woods-Saxon potential. The scalar and vector terms in the deformed potential are determined by the energies of the valence neutron and nearby orbitals, which are extracted from a self-consistent relativistic Hartree-Bogoliubov (RHB) calculation with the PC-PK1 density functional. Results: We compare the energies and widths of resonant orbitals in the recent halo nucleus candidate 37Mg using the ACCC method based on the Dirac coupled-channel equations with those determined from the scattering phase shift (SPS) method. It is found that the results from the two methods agree well for narrow resonances, whereas the SPS method fails for broad resonances. Nilsson levels for bound and resonant orbitals from the ACCC method are calculated over a wide range of deformations and show some decisive hints of halo formation in 37Mg. Conclusions: In our ACCC model for deformed potentials in the coupled-channel Dirac equations, the crossing of the configuration 1 /2 [321 ] and 5 /2 [312 ] orbitals at a deformation of approximately 0.5 enhances the probability to occupy the 1 /2 [321 ] orbital coming from 2 p3 /2 thereby explaining the recent observation of a p -wave one-neutron halo configuration in 37Mg. The resonant 1 /2 [301 ] configuration plays a crucial role in halo formation in the magnesium isotopes beyond A =40 for a wide range of deformations larger than 0.2.

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

    SciTech Connect

    Shevchenko, A.; Burda, O.; Kalmykov, Y.; Neumann-Cosel, P. von; Ponomarev, V. Yu.; Richter, A.; Wambach, J.; Carter, J.; Sideras-Haddad, E.; Cooper, G. R. J.; Fearick, R. W.; Foertsch, S. V.; Lawrie, J. J.; Neveling, R.; Smit, F. D.; Fujita, H.; Fujita, Y.; Lacroix, D.

    2009-04-15

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

  14. FPGA based pulsed NQR spectrometer

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

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

  15. SQUID detected NMR and NQR. Superconducting Quantum Interference Device.

    PubMed

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

    1998-03-01

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

  16. Temperature dependence of 35Cl NQR in 3,4-Dichlorophenol

    NASA Astrophysics Data System (ADS)

    Chandramani, R.; Devaraj, N.; Indumathy, A.; Ramakrishna, J.

    NQR frequencies in 3,4-dichlorophenol are investigated in the temperature range 77 K to room temperature. Two resonances have been observed throughout the temperature range, corresponding to the two chemically inequivalent chlorine sites. Using Bayer's theory and Brown's method torsional frequencies and their temperature dependence in this range are estimated.

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

    NASA Astrophysics Data System (ADS)

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

    2000-08-01

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

  18. Optimization of NQR Pulse Parameters using Feedback Control

    NASA Astrophysics Data System (ADS)

    Schiano, J. L.; Blauch, A. J.; Ginsberg, M. D.

    2000-02-01

    A new method for increasing the probability of detecting nuclear resonance signals is demon-strated experimentally. It is well known that the detection of signals with a low signal to noise ratio (SNR) results in missed detections of false alarms. In situations where the noise is correlated or where limited data is averaging, it may not be possible to achieve a desired SNR through averaging alone. We present an alternative approach in which a feedback algorithm automatically adjusts pulse parameters so that the SNR and probability of correct detection are increased. Experimental results are presented for the detection of 14N NQR signals.

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

    NASA Technical Reports Server (NTRS)

    Brinkmann, D.

    1995-01-01

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

  20. Cu nuclear magnetic resonance of aligned single crystals of YBa/sub 2/Cu/sub 3/O/sub 7/. sqrt. /sub delta/

    SciTech Connect

    Pennington, C.H.; Durand, D.J.; Zax, D.B.; Slichter, C.P.; Rice, J.P.; Ginsberg, D.M.

    1988-05-01

    There are two types of Cu sites in YBa/sub 2/Cu/sub 3/O/sub 7/..sqrt../sub delta/, plane and chain. One gives a nuclear quadrupole resonance (NQR) at 22.0 MHz, the other at 31.5 MHz. Measurements of nuclear spin-lattice relaxation time in the superconducting state show that the 31.5-MHz site has a much larger energy gap (as though its T/sub c/ were 200 K), but different experimental workers have differed as to whether this is the chain or plane site. We report nuclear magnetic resonance (NMR) studies at 81.1 kG and 100 K on oriented single crystals, and conclude from symmetry arguments that the 31.5-MHz NQR arises from the plane site.

  1. A miniaturized NQR spectrometer for a multi-channel NQR-based detection device

    NASA Astrophysics Data System (ADS)

    Beguš, Samo; Jazbinšek, Vojko; Pirnat, Janez; Trontelj, Zvonko

    2014-10-01

    A low frequency (0.5-5 MHz) battery operated sensitive pulsed NQR spectrometer with a transmitter power up to 5 W and a total mass of about 3 kg aimed at detecting 14N NQR signals, predominantly of illicit materials, was designed and assembled. This spectrometer uses a standard software defined radio (SDR) platform for the data acquisition unit. Signal processing is done with the LabView Virtual instrument on a personal computer. We successfully tested the spectrometer by measuring 14N NQR signals from aminotetrazole monohydrate (ATMH), potassium nitrate (PN), paracetamol (PCM) and trinitrotoluene (TNT). Such a spectrometer is a feasible component of a portable single or multichannel 14N NQR based detection device.

  2. A miniaturized NQR spectrometer for a multi-channel NQR-based detection device.

    PubMed

    Begu, Samo; Jazbinek, Vojko; Pirnat, Janez; Trontelj, Zvonko

    2014-10-01

    A low frequency (0.5-5 MHz) battery operated sensitive pulsed NQR spectrometer with a transmitter power up to 5 W and a total mass of about 3 kg aimed at detecting (14)N NQR signals, predominantly of illicit materials, was designed and assembled. This spectrometer uses a standard software defined radio (SDR) platform for the data acquisition unit. Signal processing is done with the LabView Virtual instrument on a personal computer. We successfully tested the spectrometer by measuring (14)N NQR signals from aminotetrazole monohydrate (ATMH), potassium nitrate (PN), paracetamol (PCM) and trinitrotoluene (TNT). Such a spectrometer is a feasible component of a portable single or multichannel (14)N NQR based detection device. PMID:25233110

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

    NASA Astrophysics Data System (ADS)

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

    2012-03-01

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

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

    NASA Technical Reports Server (NTRS)

    Borsa, F.; Rigamonti, A.

    1990-01-01

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

  5. New Method for Double-Resonance Spectroscopy in a Cold Quadrupole Ion Trap and Its Application to UV-UV Hole-Burning Spectroscopy of Protonated Adenine Dimer.

    PubMed

    Kang, Hyuk; Fraud, Graldine; Dedonder-Lardeux, Claude; Jouvet, Christophe

    2014-08-01

    A novel method for double-resonance spectroscopy in a cold quadrupole ion trap is presented, which utilizes dipolar resonant excitation of fragment ions in the quadrupole ion trap. Photofragments by a burn laser are removed by applying an auxiliary RF to the trap, and a probe laser detects the depletion of photofragments by the burn laser. By scanning the wavelength of the burn laser, conformation-specific UV spectrum of a cold ion is obtained. This simple and powerful method is applicable to any type of double-resonance spectroscopy in a cold quadrupole ion trap and was applied to UV-UV hole-burning spectroscopy of protonated adenine dimer. It was found that protonated adenine dimer has multiple conformers/tautomers, each with multiple excited states with drastically different excited state dynamics. PMID:26277976

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

    NASA Astrophysics Data System (ADS)

    Kume, Yoshio; Amino, Daiki; Asaji, Tetsuo

    2013-07-01

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

  7. Part I. Analyzing the distribution of gas law questions in chemistry textbooks. Part II. Chlorine-35 NQR spectra of group 1 and silver dichloromethanesulfonates

    NASA Astrophysics Data System (ADS)

    Gillette, Gabriel

    Part I. Two studies involving the gas law questions in eight high school and Advanced Placement/college chemistry textbooks were performed using loglinear analysis to look for associations among six variables. These variables included Bloom's Taxonomy (higher-order, lower-order), Book Type (high school, college), Question Format (multiple-choice, problem, short answer), Question Placement (in-chapter, end-of-chapter, test bank), Representation (macroscopic, microscopic, symbolic), and Arkansas Science Standard (conceptual, mathematical; gas laws, pressure conversion, stoichiometry). The first study, involving the conceptual gas law questions, found the Book Type and Question Placement variables had the biggest impact, each appearing in 5 of the 11 significant associations. The second study, involving the mathematical gas law questions, found the Question Placement had the biggest impact, appearing in 7 of the 11 significant associations, followed by Book Type and the Arkansas Science Standard variables, which appeared in 5 of the 11 significant associations. These studies showed that compared to the high school books, college books have fewer multiple-choice questions (compared to short-answer and problem questions), fewer in-chapter questions (compared to end-of-chapter and test bank questions), fewer questions in the chapters and more questions at the end of the chapters and fewer multiple-choice questions in and at the end of the books and more multiple-choice questions in the test banks. Part II. The dichloromethanesulfonate salts of several +1 charged cations, M+Cl2CHSO3 - (M = Li, Na, K, Rb Ag, Cs Tl) were synthesized and studied by 35Cl nuclear quadrupole resonance (NQR). Dichloromethanesulfonic acid was prepared by the methanolysis of dichloromethanesulfonyl chloride, which was neutralized with the metal carbonates to produce the corresponding metal dichloromethanesulfonate salts. This study completed the NQR investigation of the family of chloroacetates and chloromethanesulfonates of silver. The study suggests that the ability of organochlorine atoms to coordinate to silver ions decreases as the number of electron-withdrawing groups attached to carbon atom bound to the coordinating chlorine atom increases. The unusually large NQR spectral width found among M+Cl2CHCO2 - salts are not present among M+Cl2CHSO 3- salts and does not appear to be generally characteristic of the dichloromethyl family of salts.

  8. Nuclear quadrupole resonance of spin 3/2 and entangled two-qubit states

    NASA Astrophysics Data System (ADS)

    Furman, G.; Goren, S. D.; Meerovich, V.; Sokolovsky, V.

    2015-10-01

    A single spin-3/2, possessing a quadrupole moment and placed in a non-uniform electric field, is isomorphic to a system of two spins of 1/2, which can be represented as two qubits. To create these qubits, the degeneracy of the energy levels is removed by applying two radio-frequency fields with different phases and directions. The properties of entanglement between two qubits are studied. We analyze the concurrence, the entropy of entanglement, and fluctuations of the entropy in the pure and mixed states. Concurrence and entropy of entanglement in a mixed state increase with decreasing temperature and approach to their values in a pure state. For a nucleus Cu in high temperature superconductor {{YBa}}2{{Cu}}3{{{O}}}7-? , the estimation of the temperature, at which entanglement appears, gives T ?slant 0.8 ?K.

  9. Definitive solid-state 185/187Re NMR spectral evidence for and analysis of the origin of high-order quadrupole-induced effects for I=5/2.

    PubMed

    Widdifield, Cory M; Bain, Alex D; Bryce, David L

    2011-07-21

    Rhenium-185/187 solid-state nuclear magnetic resonance (SSNMR) experiments using NaReO(4) and NH(4)ReO(4) powders provide unambiguous evidence for the existence of high-order quadrupole-induced effects (HOQIE) in SSNMR spectra. Fine structure, not predicted by second-order perturbation theory, has been observed in the (185/187)Re SSNMR spectrum of NaReO(4) at 11.75 T, where the ratio of the Larmor frequency (?(0)) to the quadrupole frequency (?(Q)) is ?2.6. This is the first experimental observation that under static conditions, HOQIE can directly manifest in SSNMR powder patterns as additional fine structure. Using NMR simulation software which includes the quadrupole interaction (QI) exactly, extremely large (185/187)Re nuclear quadrupole coupling constants (C(Q)) are accurately determined. QI parameters are confirmed independently using solid-state (185/187)Re nuclear quadrupole resonance (NQR). We explain the spectral origin of the HOQIE and provide general guidelines that may be used to assess when HOQIE may impact the interpretation of the SSNMR powder pattern of any spin-5/2 nucleus in a large, axially symmetric electric field gradient (EFG). We also quantify the errors incurred when modeling SSNMR spectra for any spin-5/2 nucleus within an axial EFG using second-order perturbation theory. Lastly, we measure rhenium chemical shifts in the solid state for the first time. PMID:21629964

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

    SciTech Connect

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

    1991-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2009-07-01

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

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

    SciTech Connect

    Yesinowski, J.P.; Buess, M.L.; Garroway, A.N.; Ziegeweid, M.; Pines, A. |

    1995-07-01

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

  13. Pressure Dependence of the Chlorine NQR in Chloro Pyridines

    NASA Astrophysics Data System (ADS)

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

    2000-02-01

    The 35CI NQR frequency (?Q) and spin lattice relaxation time (T1 ) in 2,6-dichloropyridine, 2 amino 3,5-dichloropyridine and 6 chloro 2-pyridinol have been measured as a function of pressure up to 5.1 kbar at 300 K, and the data have been analysed to estimate the temperature coefficients of the NQR frequency at constant volume. All the three compounds show a non linear variation of the NQR frequency with pressure which can be described by a 2nd order polynomial in pressure. The rate of change of the NQR frequency with pressure is positive and decreases with increasing pressure. The spin lattice relaxation time T1, in all the three compounds shows a small increase with pressure, indicating that the relaxation is mainly due to the torsional motions.

  14. Nuclear magnetic resonance with dc SQUID preamplifiers

    SciTech Connect

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

    1989-03-01

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

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

    SciTech Connect

    Ziegeweid, M.A.

    1995-11-29

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

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

    PubMed

    Williams, D Keith; Hawkridge, Adam M; Muddiman, David C

    2007-01-01

    High mass measurement accuracy (MMA) is demonstrated for intact proteins and subsequent collision-induced dissociation product ions using internal calibration. Internal calibration was accomplished using a dual electrospray ionization source coupled with a hybrid quadrupole Fourier transform ion cyclotron resonance (Q-FT-ICR) mass spectrometer. Initially, analyte ions generated via the first electrospray (ESI) emitter are isolated and dissociated in the external quadrupole. This event is followed by a simultaneous switch to the calibrant ion ESI emitter and a disablement of the isolation and activation of the external quadrupole such that a broad m/z range of calibrant ions are accumulated before injecting the analyte/calibrant ion mixture into the ICR cell. Two different internal calibrant solutions were utilized in these studies to evaluate this approach for the top-down characterization of melittin and ubiquitin. While external calibration of protein fragments resulted in absolute MMA greater than 16 ppm, internal standardization significantly improved upon the MMA of both the intact proteins and their products ions which ranged from -2.0 ppm to 1.1 ppm, with an average of -0.9 ppm. This method requires limited modification to ESI-FT-ICR mass spectrometers and is applicable for both positive and negative ionization modes. PMID:16979902

  17. Nuclear magnetic and quadrupole resonances of Cu in the low-dimensional magnets Cu2M2Ge4O13 (M = Fe, Sc)

    NASA Astrophysics Data System (ADS)

    Kikuchi, J.; Nagura, S.; Nakanishi, H.; Masuda, T.

    2010-01-01

    We report on the results of nuclear magnetic and quadrupole resonances of Cu in Cu2Fe2Ge4O13 consisting of weakly coupled Cu dimers and Fe chains. In the antiferromagnetic state below 39 K, we observed nuclear resonance of Cu under the internal magnetic field at the Cu site. An analysis of the internal field based on the square-planar coordination of Cu2+suggests that the 3d hole is mainly in the dx2-y2 orbital. In Cu2Sc2Ge4O13 including only Cu dimers, we observed oscillation of Cu spin-echo intensity as a function of the separation time between ?/2 and ? pulses. This is caused by indirect nuclear spin coupling mediated by strong intradimer exchange coupling of the electronic spins, indicating that the dimers are magnetically well isolated in these materials.

  18. Quadrupole-enhanced Raman scattering.

    PubMed

    Hastings, Simon P; Swanglap, Pattanawit; Qian, Zhaoxia; Fang, Ying; Park, So-Jung; Link, Stephan; Engheta, Nader; Fakhraai, Zahra

    2014-09-23

    Dark, nonradiating plasmonic modes are important in the Raman enhancement efficiency of nanostructures. However, it is challenging to engineer such hotspots with predictable enhancement efficiency through synthesis routes. Here, we demonstrate that spiky nanoshells have designable quadrupole resonances that efficiently enhance Raman scattering with unprecedented reproducibility on the single particle level. The efficiency and reproducibility of Quadrupole Enhanced Raman Scattering (QERS) is due to their heterogeneous structure, which broadens the quadrupole resonance both spatially and spectrally. This spectral breadth allows for simultaneous enhancement of both the excitation and Stokes frequencies. The quadrupole resonance can be tuned by simple modifications of the nanoshell geometry. The combination of tunability, high efficiency, and reproducibility makes these nanoshells an excellent candidate for applications such as biosensing, nanoantennaes, and photovoltaics. PMID:25157600

  19. Single crystal zeeman effect studies on 35Cl NQR lines of 2,6-dichlorophenol

    NASA Astrophysics Data System (ADS)

    Prasad, N. V. L. N.; Venkatacharyulu, P.; Premaswarup, D.

    1987-10-01

    Zeeman effect studies on the two 35Cl NQR lines in cylindrical single crystals of 2,6-dichlorophenol were carried out using a self-quenched super-regenerative NQR spectrometer to obtain information on the nature of the crystalline unit cell and the effect of hydrogen bonding on the electric field gradient tensor. Analysis of the experimental data reveals: (1) the results are in good agreement with those reported from X-ray studies; (2) the crystal is unequivocally identified as belonging to the orthorhombic system; (3) there are two crystallographically equivalent and four physically nonequivalent directions for the principal field gradients for both the low and high frequency resonance lines; (4) the directions of the crystalline a, b, c axes are uniquely identified as (90°, 0°), (0°, -), and (90°, 90°); (5) the b-axis is identified as the growth axis; (6) there are a minimum of four molecules per unit cell, the four molecules lie in different planes, which are, however, connected by symmetry operations; (7)_there exists a weak intramolecular hydrogen bonding in the crystal; (8) the asymmetry parameters for the loci corresponding to the low frequency resonance line, which is affected by hydrogen bonding, are less than the asymmetry parameters of the loci corresponding to the high frequency resonance line, which is not affected by hydrogen bonding; (9) the single bond and ionic bond characters for the hish frequency line are less than that of the low frequency line, while the double bond character for the low frequency line is less than that of the high frequency line and (10) the small deviation between the single bond and double bond characters of the two resonance lines is attributed to the existence of weak hydrogen bonding in the crystal.

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

    NASA Astrophysics Data System (ADS)

    Fan, N. Q.; Heaney, Michael B.; Clark, John; Newitt, D.; Wald, Lawrence L.; Hahn, Erwin L.; Bierlecki, A.; Pines, A.

    1988-08-01

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

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

    SciTech Connect

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

    1988-08-01

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

  2. 63,65Cu Nuclear Resonance Study of the Coupled Spin Dimers and Chains Compound Cu2Fe2Ge4O13

    NASA Astrophysics Data System (ADS)

    Kikuchi, Jun; Nagura, Shiro; Murakami, Kazumasa; Masuda, Takatsugu; Redhammer, Gnther J.

    2013-03-01

    Nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) of Cu have been measured in a coupled spin dimers and chains compound Cu2Fe2Ge4O13. Cu NQR has also been measured in an isostructural material Cu2Sc2Ge4O13 including only spin dimers. Comparison of the temperature dependence of the 63Cu nuclear spin--lattice relaxation rate between the two compounds reveals that the Fe chains in Cu2Fe2Ge4O13 do not change a spin gap energy of the Cu dimers from that in Cu2Sc2Ge4O13, contributing additionally to the relaxation rate at the Cu site. A modestly large internal field of 3.39 T was observed at the Cu site in the antiferromagnetic state of Cu2Fe2 Ge4O13 at 4.2 K, which is partly because of quantum reduction of the ordered moment of a Cu atom. The internal field and the ordered moment of Cu are noncollinear due to large anisotropy of the hyperfine interaction at the Cu site. A model analysis of the internal field based on the fourfold planar coordination of Cu suggests that a 3d hole of the Cu2+ ion is mainly in the d(x2-y2) orbital state.

  3. Chlorine-35 NQR and 1H NMR study of guest structure and dynamics in the thiourea-hexachloroethane inclusion compound

    NASA Astrophysics Data System (ADS)

    Panich, A. M.; Krieger, Ju H.; Semenov, A. R.; Goren, S. D.; Chekhova, G. N.

    2000-07-01

    Atom-atomic potential calculation of the channel non-stoichiometric thiourea-hexachloroethane inclusion compound shows that the structure of the guest sublattice comprises two types of finite molecular chain, having different structure and separated by domain walls. In the present paper we present results of 35Cl NQR and 1H NMR measurements of thiourea-hexachloroethane, [2.95(NH2)2CS]C2Cl6, in the temperature range from 7.5 to 90 K, which confirm this model and show the existence of such a state at least below 60 K. Two resonances in the NQR spectra were assigned to the two nearly commensurate regions, while the third resonance, showing an anomalous behaviour, was attributed to the guest molecules in the domain wall. The observed structure results from the different periodicity of the guest and host substructures and shows a difference from conventional continuum models of the incommensurate state. Propagation motion of the domain wall over the channel is discussed.

  4. Chemical structure and intra-molecular effects on NMR-NQR tensors of harmine and harmaline alkaloids

    NASA Astrophysics Data System (ADS)

    Ahmadinejad, Neda; Tahan, Arezoo; Talebi Tari, Mostafa

    2016-02-01

    Density functional theory (DFT) methods were used to analyze the effects of molecular structure and ring currents on the NMR chemical shielding tensors and NQR frequencies of harmine and harmaline alkaloids in the gas phase. The results demonstrated that NMR tensors and NQR frequencies of 15N nuclei in these compounds depend on chemical environment and resonance interactions. Hence, their values are obviously different in the mentioned structures. The interpretation of natural bond orbital (NBO) data suggests that in harmine structure, the lone pair participation of N9 in π-system electron clouds causes to development of aromaticity nature in pyrrole ring. However, the chemical shielding around N9 atom in harmine structure is higher than in harmaline, while in harmaline structure, lone pair participation of N2 in π-system electron clouds causes to development of aromaticity nature in pyridine ring. Hence, chemical shielding around N2 atom in harmaline structure is higher than in harmine. It can be deduced that by increasing lone pair electrons contribution of nitrogen atoms in ring resonance interactions and aromaticity development, the values of NMR chemical shielding around them increase, while χ and q zz values of these nuclei decrease.

  5. Nuclear magnetic resonance experiments with dc SQUID amplifiers

    SciTech Connect

    Heaney, M.B. . Dept. of Physics Lawrence Berkeley Lab., CA )

    1990-11-01

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

  6. Nuclear magnetic resonance experiments with DC SQUID amplifiers

    NASA Astrophysics Data System (ADS)

    Heaney, M. B.

    1990-11-01

    The development and fabrication of dc SQUIDs (Superconducting Quantum Interference Devices) with Nb/Al2O3/Nb Josephson junctions is described. A theory of the dc SQUID as a radio-frequency amplifier is presented, with an optimization strategy that accounts for the loading and noise contributions of the postamplifier and maximizes the signal-to-noise ratio of the total system. The high sensitivity of the dc SQUID is extended to high field NMR. A dc SQUID is used as a tuned radio-frequency amplifier to detect pulsed nuclear magnetic resonance at 32 MHz from a metal film in a 3.5 Tesla static field. A total system noise temperature of 11 K has been achieved, at a bath temperature of 4.2 K. The minimum number of nuclear Bohr magnetons observable from a free precession signal after a single pulse is about 2 x 10(exp 17) in a bandwidth of 25 kHz. In a separate experiment, a dc SQUID is used as a rf amplifier in a NQR experiment to observe a new resonance response mechanism. The net electric polarization of a NaClO3 crystal due to the precessing electric quadrupole moments of the Cl nuclei is detected at 30 MHz. The sensitivity of NMR and NQR spectrometers using dc SQUID amplifiers is compared to the sensitivity of spectrometers using conventional rf amplifiers. A SQUID-based spectrometer has a voltage sensitivity which is comparable to the best achieved by a FET-based spectrometer, at these temperatures and operating frequencies.

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

    SciTech Connect

    Shastri, A.; Borsa, F.; Torgeson, D.R.; Shield, J.E.; Goldman, A.I. )

    1994-12-01

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

  8. 35C NQR studies in 2,4,6-,2,3,6-, and 2,3,4-trichloro anisoles

    NASA Astrophysics Data System (ADS)

    Rukmani, K.; Ramakrishna, J.

    1985-02-01

    The chlorine-35 NQR frequencies and their temperature variation in 2,4,6-, 2,3,6- and 2,3,4-trichloro anisoles have been studied and compared with the corresponding chlorophenols with a view to studying the effect of hydrogen bonding. The observed frequencies have been assigned to the various chlorines with the help of the additive model of the substituent effect. The temperature dependence has been analysed in terms of the BayerKushidaBrown models. The torsional frequencies and their temperature dependence have been calculated numerically under a two mode approximation. A comparison of the trichloro anisoles with the corresponding trichloro phenols has shown that the resonance frequency decreases due to hydrogen bonding while the torsional frequencies are not affected.

  9. Studies of Ga NMR and NQR in SrGa4

    NASA Astrophysics Data System (ADS)

    Niki, H.; Higa, N.; Nakamura, S.; Kuroshima, H.; Toji, T.; Yogi, M.; Nakamura, A.; Hedo, M.; Nakama, T.; ?nuki, Y.; Harima, H.

    2015-04-01

    In order to microscopically investigate the properties in SrGa4, the Ga NMR measurements of a powder sample were carried out. The Ga NMR spectra corresponding to Ga(I) and Ga(II) sites are obtained. The NMR spectra of 69&71Ga (a nuclear spin I = 3/2) in the powder sample of SrGa4 do not take a typical powder pattern caused by the NQR interaction, but take the spectra consisting of three well resolved resonance-lines, which indicates that the nonuniform distribution of crystal orientation in the powder sample occurs because of the magnetic anisotropy. From the analysis of the Ga NMR spectrum, it is found that the ab-plane of the crystal is parallel to the external magnetic field, which would be attributed to the anisotropy of the magnetic susceptibility with the easy axis parallel to the ab-plane. This result is also confirmed by the 69Ga NQR in SrGa4. The Knight shifts of the 69Ga(I) and 69Ga(II) shift slightly to the negative side with decreasing temperature due to the core polarization of the d-electrons. The values of the Knight shift of the 69Ga(I) and 69Ga(II) are 0.01 and -0.11 % at 4.2 K, and 0.09 and -0.08 % at 300 K, respectively. The values of the 1/ T 1 T of the NMR of both 69Ga(I) and 69Ga(II) are almost constant between 4.2 and 100 K, whose values are 1.5 s -1 K -1 at 69Ga(I) and 0.12 s -1 K -1 at 69Ga(II), while the 1/ T 1 T slightly increase above 100K with increasing temperature. The value of T 1 of 69Ga(I) is one order of magnitude less than that of 69Ga(II).

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

    NASA Astrophysics Data System (ADS)

    Shimada, Rintaro; Hamaguchi, Hiro-o.

    2014-05-01

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

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

    SciTech Connect

    Shimada, Rintaro; Hamaguchi, Hiro-o

    2014-05-28

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

  12. DC SQUID detection of new magnetic resonance phenomena

    SciTech Connect

    Sleator, T.

    1986-01-01

    A dc Superconducting QUantum Interference Device (SQUID) was used as a tuned radio-frequency amplifier at liquid helium temperatures to detect very-low-signal magnetic resonance phenomena. Three experiments were performed. In the first experiment, a dc SQUID was used to detect pulsed nuclear quadrupole resonance at about 30 MHz. At a bath temperature of 4.2K, a total system noise temperature of 6 +/- 1K was achieved, with a quality factor Q of 2500. A novel Q-spoiler, consisting of a series array of Josephson tunnel junction, reduced the ring-down time of the tuned circuit after each pulse. The minimum number of nuclear Bohr magnetons observable from a free-precession signal after a single pulse was about 2 x 10/sup 16/ in a bandwidth of 10 kHz. In the second experiment, a sample of nuclear spins was placed in the inductor of a tuned LCR circuit and the spectral density of current fluctuations in the circuit was measured using a dc SQUID as an rf amplifier. The measurements were made in liquid helium at 1.5K on samples of NaClO/sub 3/ and KClO/sub 3/, each of which exhibit a /sup 35/Cl NQR transition at about 30 MHz. In the third experiment, precessing nuclear quadrupole moments were observed to induce oscillating electric dipole moments in neighboring atoms. The /sup 35/Cl nuclei of a single crystal of NaClO/sub 3/ placed between the plates of a capacitor were excited into precession by a rf pulse.

  13. 35Cl NQR study of incommensurate state in thiourea-hexachloroethane inclusion compound

    NASA Astrophysics Data System (ADS)

    Panich, A. M.; Semenov, A. R.; Chekhova, G. N.; Krieger, Ju. H.; Goren, S. D.

    1999-04-01

    A study of the incommensurate phase of the channel thiourea-hexachloroethane inclusion compound by means of 35Cl NQR, in the temperature range from 68 to 88 K, is presented. Hahn echo measurements indicate the slow diffusion-like motion of the modulation wave. This motion is obtained close to the transition temperature Ti˜90 K. At higher temperatures, the NQR spectrum is not observed. We attribute this fact to the reorientational mobility of C 2Cl 6 molecules in the host sublattice, probably accompanied by an order-disorder phase transition.

  14. 127I NQR, 1H NMR and crystal structure of a novel compound, guanidinium heptaiodomercurate(II) [C(NH 2) 3] 3Hg 2I 7

    NASA Astrophysics Data System (ADS)

    Terao, Hiromitsu; Kai, Yoshihiko; Gesing, Thorsten M.; Ishihara, Hideta; Furukawa, Yoshihiro; Gowda, B. Thimme

    2009-08-01

    The crystal structure of [C(NH 2) 3] 3Hg 2I 7 crystallizes in the monoclinic space group C2/ c with a = 10.301(2), b = 11.919(2), c = 22.143(4) , ? = 100.50(3), and Z = 4. The asymmetric unit of the structure consists of an Hg 2I 73- anion and three guanidinium cations [C(NH 2) 3] +. The Hg 2I 73- anion is composed of two distorted HgI 4 tetrahedra which share an apex of I(4) atom and are related to each other by the C 2 axis. The lengths of the four Hg-I bonds of the tetrahedron are different, the longest being the bridging Hg-I(4) bond. In accordance with the crystal structure, four 127I NQR resonance lines have been observed and are assigned to m = 1/2 ? 3/2 transitions. With decreasing temperature one line assigned to the bridging I(4) atom faded out around 250 K. The temperature dependence of 1H NMR T1 has been analyzed by postulating the C 3 reorientations of two crystallographically independent cations with the BPP and the Arrhenius type relations. The hydrogen bond interactions N-H⋯I are important in the architecture of the crystal structure, which manifest themselves on the differences in the Hg-I bond lengths, in the NQR frequencies, and in the activation energies of the cation reorientations.

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

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

    The ion current achievable from high intensity ECR sources for highly charged ions is limited by the high space charge. This makes classical extraction systems for the transport and subsequent matching to a radio frequency quadrupole (RFQ) accelerator less efficient. The direct plasma injection (DPI) method developed originally for the laser ion source avoids these problems and uses the combined focusing of the gap between the ion source and the RFQ vanes (or rods) and the focusing of the rf fields from the RFQ penetrating into this gap. For high performance ECR sources that use superconducting solenoids, the stray magnetic field of the source in addition to the DPI scheme provides focusing against the space charge blow-up of the beam. A combined extraction/matching system has been designed for a high performance ECR ion source injecting into an RFQ, allowing a total beam current of 10 mA from the ion source for the production of highly charged 238U40+ (1.33 mA) to be injected at an ion source voltage of 60 kV. In this design, the features of IGUN have been used to take into account the rf-focusing of an RFQ channel (without modulation), the electrostatic field between ion source extraction and the RFQ vanes, the magnetic stray field of the ECR superconducting solenoid, and the defocusing space charge of an ion beam. The stray magnetic field is shown to be critical in the case of a matched beam.

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

    SciTech Connect

    Rodrigues, G. Kanjilal, D.; Roy, A.; Becker, R.; Baskaran, R.

    2014-02-15

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

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

    PubMed

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

    2014-02-01

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

  18. The Conformational Changes Induced by Ubiquinone Binding in the Na+-pumping NADH:Ubiquinone Oxidoreductase (Na+-NQR) Are Kinetically Controlled by Conserved Glycines 140 and 141 of the NqrB Subunit*

    PubMed Central

    Strickland, Madeleine; Juárez, Oscar; Neehaul, Yashvin; Cook, Darcie A.; Barquera, Blanca; Hellwig, Petra

    2014-01-01

    Na+-pumping NADH:ubiquinone oxidoreductase (Na+-NQR) is responsible for maintaining a sodium gradient across the inner bacterial membrane. This respiratory enzyme, which couples sodium pumping to the electron transfer between NADH and ubiquinone, is not present in eukaryotes and as such could be a target for antibiotics. In this paper it is shown that the site of ubiquinone reduction is conformationally coupled to the NqrB subunit, which also hosts the final cofactor in the electron transport chain, riboflavin. Previous work showed that mutations in conserved NqrB glycine residues 140 and 141 affect ubiquinone reduction and the proper functioning of the sodium pump. Surprisingly, these mutants did not affect the dissociation constant of ubiquinone or its analog HQNO (2-n-heptyl-4-hydroxyquinoline N-oxide) from Na+-NQR, which indicates that these residues do not participate directly in the ubiquinone binding site but probably control its accessibility. Indeed, redox-induced difference spectroscopy showed that these mutations prevented the conformational change involved in ubiquinone binding but did not modify the signals corresponding to bound ubiquinone. Moreover, data are presented that demonstrate the NqrA subunit is able to bind ubiquinone but with a low non-catalytically relevant affinity. It is also suggested that Na+-NQR contains a single catalytic ubiquinone binding site and a second site that can bind ubiquinone but is not active. PMID:25006248

  19. Spin dynamics in CuO and Cu[sub 1[minus][ital x

    SciTech Connect

    Carretta, P.; Corti, M.; Rigamonti, A. )

    1993-08-01

    [sup 63]Cu nuclear quadrupole resonance (NQR), nuclear antiferromagnetic resonance (AFNMR), and spin-lattice relaxation, as well as [sup 7]Li NMR and relaxation measurements in CuO and in Cu[sub 1[minus][ital x

  20. Nuclear-quadrupole induction of atomic polarization

    SciTech Connect

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

    1988-11-01

    Nuclear-quadrupole-induced electric signals are measured as a new resonance response mechanism that is the reciprocal of the Stark effect in magnetic resonance. In single crystals that have noncentrosymmetry with respect to the sites of precessing nuclear-quadrupole moments, the electronic polarizability of atoms and chemical bonds on opposite sides of the nuclear-quadrupole moment is not the same. The oscillating electric field produced by the quadrupole moment induces a net electric dipole moment in its neighboring electronic environment. The coherent summation of these dipole moments over the Boltzmann distribution of the nuclear ensemble produces an oscillating macroscopic electric dipole moment. The sample is placed between the plates of a capacitor that is tuned with an inductance to the nuclear precession frequency. Coherent nuclear precession is initiated following a rf magnetic field pulse that tips the nuclear spins into the precession mode. The voltage signal from the capacitor gives rise to an oscillating current in the series circuit and magnetic flux in the inductor. Stray magnetic induction pickup signals are balanced out. The flux is coupled to a dc superconducting quantum interference device (SQUID), which produces a voltage output at the nuclear-quadrupole resonance frequency of approx.30 MHz for /sup 35/Cl nuclei in NaClO/sub 3/ at 4.2 K. The /sup 35/Cl nucleus induces electric dipole moments in nearby oxygen atoms bonded to the Cl atom. Measured free-precession electric signals are compared to the predictions of a point-oxygen-atom polarizability model applied to the Cl: O bond. The technique is sensitive to chirality and to bond angles.

  1. Correcting Quadrupole Roll in Magnetic Lenses with Skew Quadrupoles

    SciTech Connect

    Walstrom, Peter Lowell

    2014-11-10

    Quadrupole rolls (i.e. rotation around the magnet axis) are known to be a significant source of image blurring in magnetic quadrupole lenses. These rolls may be caused by errors in mechanical mounting of quadrupoles, by uneven radiation-induced demagnetization of permanent-magnet quadrupoles, etc. Here a four-quadrupole ×10 lens with so-called ”Russian” or A -B B-A symmetry is used as a model problem. Existing SLAC 1/2 in. bore high-gradient quadrupoles are used in the design. The dominant quadrupole roll effect is changes in the first-order part of the transfer map (the R matrix) from the object to the image plane (Note effects on the R matrix can be of first order in rotation angle for some R-matrix elements and second order in rotation angle for other elements, as shown below). It is possible to correct roll-induced image blur by mechanically adjusting the roll angle of one or more of the quadrupoles. Usually, rotation of one quadrupole is sufficient to correct most of the combined effect of rolls in all four quadrupoles. There are drawbacks to this approach, however, since mechanical roll correction requires multiple entries into experimental area to make the adjustments, which are made according to their effect on images. An alternative is to use a single electromagnetic skew quadrupole corrector placed either between two of the quadrupoles or after the fourth quadrupole (so-called “non-local” correction). The basic feasibility of skew quadrupole correction of quadrupole roll effects is demonstrated here. Rolls of the third lens quadrupole of up to about 1 milliradian can be corrected with a 15 cm long skew quadrupole with a gradient of up to 1 T/m. Since the effect of rolls of the remaining three lens quadrupoles are lower, a weaker skew quadrupole can be used to correct them. Non-local correction of quadrupole roll effects by skew quadrupoles is shown to be about one-half as effective as local correction (i.e. rotating individual quadrupoles to zero roll angle or placing skew quadrupole correctors in the bores of main quadrupoles).

  2. Temperature variation of ultralow frequency modes and mean square displacements in solid lasamide (diuretic drug) studied by 35Cl-NQR, X-ray and DFT/QTAIM.

    PubMed

    Latosi?ska, Jolanta Natalia; Latosi?ska, Magdalena; Kasprzak, Jerzy; Tomczak, Magdalena; Maurin, Jan Krzysztof

    2012-10-25

    The application of combined (35)Cl-NQR/X-ray/DFT/QTAIM methods to study the temperature variation of anisotropic displacement parameters and ultralow frequency modes of anharmonic torsional vibrations in the solid state is illustrated on the example of 2,4-dichloro-5-sulfamolybenzoic acid (lasamide, DSBA) which is a diuretic and an intermediate in the synthesis of furosemide and thus its common impurity. The crystallographic structure of lasamide is solved by X-ray diffraction and refined to a final R-factor of 3.06% at room temperature. Lasamide is found to crystallize in the triclinic space group P-1, with two equivalent molecules in the unit cell a = 7.5984(3) , b = 8.3158(3) , c = 8.6892(3) ; ? = 81.212(3), ? = 73.799(3), ? = 67.599(3). Its molecules form symmetric dimers linked by two short and linear intermolecular hydrogen bonds O-HO (O-HO = 2.648 and ?OHO = 171.5), which are further linked by weaker and longer intermolecular hydrogen bonds N-HO (N-HO = 2.965 and ?NHO = 166.4). Two (35)Cl-NQR resonance frequencies, 36.899 and 37.129 MHz, revealed at room temperature are assigned to chlorine sites at the ortho and para positions, relative to the carboxyl functional group, respectively. The difference in C-Cl(1) and C-Cl(2) bond lengths only slightly affects the value of (35)Cl-NQR frequencies, which results mainly from chemical inequivalence of chlorine atoms but also involvement in different intermolecular interactions pattern. The smooth decrease in both (35)Cl-NQR frequencies with increasing temperature in the range of 77-300 K testifies to the averaging of EFG tensor at each chlorine site due to anharmonic torsional vibrations. Lasamide is thermally stable; no temperature-induced release of chlorine or decomposition of this compound is detected. The temperature dependence of ultralow frequency modes of anharmonic small-angle internal torsional vibrations averaging EFG tensor and mean square angle displacements at both chlorine sites is derived from the (35)Cl-NQR temperature dependence. The frequencies of torsional vibrations higher for the para site than the ortho site are in good agreement with those obtained from thermal parameters obtained from X-ray studies. The mean square angle displacements are in good agreement with those estimated from X-ray data with the use of the TLS model. The detailed DFT/QTAIM analysis suggests that the interplay between different hydrogen bonds in adjacent molecules forming dimers is responsible for the differences in flexibility of the carboxyl and sulphonamide substituents as well as both C-Cl(1) and C-Cl(2) bonds. Three ultralow wavenumber modes of internal vibrations in Raman and IR spectra obtained at the B3LYP/6-311++G(d,p) level close to those obtained within the TLS model suggest that internal and external modes of vibrations are not well separated. PMID:23020838

  3. Quadrupole and magnetic mechanisms of 209Bi spin-lattice relaxation in Bi4Ge3O12

    NASA Astrophysics Data System (ADS)

    Gippius, A. A.; Khozeev, D. F.; Morozova, E. N.; Orlov, V. G.; Shlikov, M. P.; Kargin, Yu F.

    2002-04-01

    The nuclear spin-lattice relaxation in the Bi4Ge3O12 single crystal was studied by the 209Bi NQR spin-echo technique. The recovery curves were measured for all 209Bi NQR transitions of nuclear spin I = 9/2 in a large temperature range 10-230 K. The experimental relaxation curves were described in terms of the single effective spin-lattice relaxation time T1*. The temperature dependence of 1/T1* was close to a Tn-law with n = 2.4-2.7. A theoretical treatment was given for the nuclear spin-lattice relaxation in the multi-level system for the case of a single-axial crystalline electric field. Both quadrupole and magnetic mechanisms of relaxation were taken into account. In separating the quadrupole and magnetic contributions, an idea of Rega (Rega T 1991 J. Phys.: Condens. Matter 3 1871) was used. To extract the temperature dependences of the parameters W1, W2 and WM the fitting procedure for calculated and experimental relaxation times was used. High-accuracy measurements of the recovery curves enable us to conclude that the magnetic mechanism contributes noticeably to the spin-lattice relaxation in Bi4Ge3O12 at T?50 K.

  4. 35Cl NQR Spectra of several 2,2-bis- p-chlorophenyl chloroethane derivatives

    NASA Astrophysics Data System (ADS)

    Nogaj, B.; Pietrzak, J.; Wielopolska, E.; Schroeder, G.; Jarczewski, A.

    Measurement of NQR line frequency at 77 K have been performed for the following compounds: 1-chloro-2,2-bis-(p-chlorophenyl) ethylene (DDMU), 1,1-dichloro-2,2-bis-(p-chlorophenyl) ethylene (DDE), 1,1-dichloro-2,2-bis-(p-chlorophenyl) ethane (ODD), 1,1,1-trichloro-2,2-bis (p-chlorophenyl) ethane (DDT). An attempt to assign spectrum lines to particular Cl nuclei in a molecule has been made. Molecular and crystallographic inequivalences occurring in these compounds have been considered. Comparison of the NQR and crystallographic data revealed the influence of phenyl rings conformation on electric charge distribution in the studied molecules.

  5. Quadrupole Coupling in Purines and Pyrimidines by Hartree-Fock Lattice Calculations of Electric Field Gradients

    NASA Astrophysics Data System (ADS)

    Palmer, Michael H.

    1996-06-01

    We present ab initio Hartree-Fock lattice calculations on adenine, guanine and hypoxanthine, and some pyrimidines, including cytosine and uracil derivatives. The electric field gradients at the nitrogen centres are related to NQR experimental determinations of nuclear quadrupole coupling constants. The calculations were performed as lattice calculations in the unit cell environment, with 6-31G or double zeta basis sets at the SCF level. The present analysis strongly suggests that ?zz at N3 in cytosine, N3 in guanine are both positive, and approximately tangential to the ring at that centre. In contrast, N7 in guanine is like most other azine-type N centres, with a largely radial direction for ?zz. The 3-protonated cytosine ring has ?zz as the local ?-direction.

  6. Mutual effect of ligands in nitrido and nitroso complexes of osmium and ruthenium from NQR data

    SciTech Connect

    Kravchenko. E.A.; Burtsev, M.Yu.; Sinitsyn, M.N.; Svetlov, A.A.; Kokunov, Ya.V.; Buslaev, A.

    1987-11-01

    The purpose of this investigation was to study by NQR the spectral results of the mutual ligand effect in complex compounds having various types of short bonds. The authors obtained the /sup 35/Cl, /sup 81/Br, and /sup 127/I NQR spectra of a large number of halogen complexes of osmium and ruthenium having short Os=N and M in equilibrium NO bonds of the following types: R(OsNHal/sub 4/) (R = (Ph/sub 4/P)/sup +/, (Bu/sub 4/N)/sup +/; Hal = Cl/sup -/, Br/sup -/, I/sup -/), K/sub 2/(OsNCl/sub 5/), Rb/sub 2/(OsNBr/sub 5/), (NH/sub 4/)/sub 2/(OsNBr/sub 5/), K(OsNHal/sub 4/L) (Hal = Cl/sup -/, Br/sup -/; L = H/sub 2/O, CH/sub 3/CN), K/sub 2/(MNOHal/sub 5/) (M = Os, Ru; Hal = Cl/sup -/, Br/sup -/, I/sup -/). The experimental NQR values measured are connected by the Townes and Dailey theory with the chemical bond characteristics i, sigma, ..pi.., the degree of the ionic, the sigma-covalent, and the ..pi..-covalent natures respectively ( i + sigma + ..pi.. = 1).

  7. Variable Permanent Magnet Quadrupole

    SciTech Connect

    Mihara, T.; Iwashita, Y.; Kumada, M.; Spencer, C.M.; /SLAC

    2007-05-23

    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.

  8. Identification and fragmentation pathways of caffeine metabolites in urine samples via liquid chromatography with positive electrospray ionization coupled to a hybrid quadrupole linear ion trap (LTQ) and Fourier transform ion cyclotron resonance mass spectrometry and tandem mass spectrometry.

    PubMed

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

    2009-04-01

    Liquid chromatography (LC) with positive ion electrospray ionization (ESI+) coupled to a hybrid quadrupole linear ion trap (LTQ) and Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS) was employed for the simultaneous determination of caffeine and its metabolites in human urine within a single chromatographic run. LC/ESI-FTICRMS led to the unambiguous determination of the molecular masses of the studied compounds without interference from other biomolecules. A systematic and comprehensive study of the mass spectral behaviour of caffeine and its fourteen metabolites by tandem mass spectrometry (MS/MS) was performed, through in-source ion trap collision-induced dissociation (CID) of the protonated molecules, [M+H](+). A retro-Diels-Alder (RDA) process along with ring-contraction reactions were the major fragmentation pathways observed during CID. The base peak of xanthine precursors originates from the loss of methyl isocyanate (CH(3)NCO, 57 Da) or isocyanic acid (HNCO, 43 Da), which in turn lose a CO unit. Also uric acid derivatives shared a RDA rearrangement as a common fragmentation process and a successive loss of CO(2) or CO. The uracil derivatives showed a loss of a ketene unit (CH(2)CO, 42 Da) from the protonated molecule along with the loss of H(2)O or CO. To assess the potential of the present method three established metabolite ratios to measure P450 CYP1A2, N-acetyltransferase and xanthine oxidase activities were evaluated by a number of identified metabolites from healthy human urine samples after caffeine intake. PMID:19260028

  9. NQR study of neutral-ionic phase transition and quantum paraelectric state in organic charge-transfer complexes

    NASA Astrophysics Data System (ADS)

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

    2008-12-01

    NQR measurements were performed for the charge-transfer complexes DMTTF-QBr nCl n-4 under ambient and hydrostatic pressures in order to understand the neutral-ionic phase transition and the quantum critical behavior. The 35Cl NQR spectrum of DMTTF-QCl 4 showed a splitting and a shift below Tc, indicating the occurrence of dimerization and charge transfer. The spin-lattice relaxation rate 1/ T1 showed a peak anomaly around Tc, reflecting the critical slowing down. The quantum paraelectric states in DMTTF-2,6-QBr 2Cl 2 and pressured DMTTF-QBr 4 were studied by the 79Br NQR. We found the microscopic evidence for the evolution of the critical fluctuations at low temperatures in the temperature dependence of spin-lattice relaxation rate.

  10. Stabilized radio frequency quadrupole

    DOEpatents

    Lancaster, Henry D.; Fugitt, Jock A.; Howard, Donald R.

    1984-01-01

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

  11. Stabilized radio frequency quadrupole

    DOEpatents

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

    1984-12-25

    Disclosed is a long-vane stabilized radio frequency resonator for accelerating charged particles and including means defining a radio frequency resonator cavity, a plurality of long vanes mounted in the defining means for dividing the cavity into sections, and means interconnecting opposing ones of the plurality of vanes for stabilizing the resonator. 5 figs.

  12. Application of two-dimensional exchange nuclear magnetic resonance techniques for the study of incommensurate solids

    NASA Astrophysics Data System (ADS)

    Muntean, Ligia Aurora

    This dissertation includes a study of atomic dynamics in incommensurate systems by specialized nuclear magnetic resonance (NMR) techniques, such as two-dimensional (2D) exchange NMR, and Hahn spin-echo decay. The atomic dynamics described by the diffusion-like motion of the modulation wave in incommensurate phases is one of the subjects of condensed matter physics that is not fully understood and has attracted a great deal of attention in recent years. Our Hahn spin-echo decay and 2D exchange and exchange-difference NMR experiments have contributed to understanding some of the aspects of this debated subject and have brought conclusive experimental evidence for the existence of the modulation wave diffusion in Rb2ZnCl 4 and BaNaNb5O15. We performed 87Rb NMR and 35Cl nuclear quadrupole resonance (NQR) Hahn spin echo magnetization decay measurements in the incommensurate (I) phase of Rb2ZnCl4. From these measurements we obtained values for the diffusion coefficients for 87Rb NMR and 35Cl NQR and found them to be similar. This fact strongly supports the existence of modulation wave diffusion in the I phase, that should affect both Rb and Cl ions comparably. We also used 87Rb 2D exchange-difference NMR to study atomic motions in the incommensurate (I) and paraelectric (P) phases, to elucidate the nature of the I-P transition. The P phase results are identified as normal modes arising from simultaneous reorientations of ZnCl4 tetrahedra and corresponding Rb ions displacements between two sites. These normal modes freeze out in the I phase and change to the diffusion-like motion of the modulation wave. This dissertation also includes a study of modulation wave dynamics in the I phase of barium sodium niobate (BSN) by 2D exchange NMR. The modulation wave diffusion has been previously inferred in BSN from a complementary experiment, the Hahn spin-echo decay. However, since this experiment cannot unambiguously distinguish between different types of motional mechanisms, the modulation wave diffusion interpretation of the Hahn echo experimental results could still be under question. Our 93Nb 2D exchange NMR data provide additional strong evidence for the existence of progressive diffusion-like motion of the modulation wave and rules out a two-site jump model in BSN.

  13. Thermal conductivity and resonant multipole interactions.

    NASA Technical Reports Server (NTRS)

    Nyeland, C.; Mason, E. A.; Monchick, L.

    1972-01-01

    Investigation of the influence of resonant multipole interactions on exchanges of rotational energy in molecular collisions, by means of a simple two-state impact-parameter approximation. It is found that dipole-quadrupole and quadrupole-quadrupole interactions can have a significant effect for molecules with low moments of inertia.

  14. Nuclear Magnetic Resonance

    NASA Astrophysics Data System (ADS)

    Andrew, E. R.

    2009-06-01

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

  15. Hybridization-driven gap in U3Bi4Ni3: a 209Bi NMR/NQR study

    SciTech Connect

    Baek, Seung H

    2009-01-01

    We report {sup 209}Bi nuclear-magnetic-resonance and nuclear-quadrupole-resonance measurements on a single crystal of the Kondo insulator U{sub 3}Bi{sub 4}Ni{sub 3}. The {sup 209}Bi nuclear-spin-lattice relaxation rate (T{sub 1}{sup -1}) shows activated behavior and is well fit by a spin gap of 220 K. The {sup 209}Bi Knight shift (K) exhibits a strong temperature dependence arising from 5f electrons, in which K is negative at high temperatures and increases as the temperature is lowered. Below 50 K, K shows a broad maximum and decreases slightly upon further cooling. Our data provide insight into the evolution of the hyperfine fields in a fully gapped Kondo insulator based on 5f electron hybridization.

  16. Temperature and baric dependence of nuclear quadruple resonance spectra in indium and gallium monoselenides

    NASA Astrophysics Data System (ADS)

    Khandozhko, Victor; Raranskii, Nikolai; Balazjuk, Vitaly; Samila, Andriy; Kovalyuk, Zahar

    2013-12-01

    Pulsed radiospectroscopy method has been used to study nuclear quadruple resonance (NQR) spectra of 69Ga and 115In isotopes in the layered semiconductors GaSe and InSe. It has been found that in GaSe and InSe there is a considerable temperature dependence of NQR frequency which in the temperature range of 250 to 390 K is practically linear with conversion slope 1.54 kHz/degree for 69Ga and 2.35 kHz/degree for 115In. In the same crystals the effect of uniaxial pressure on NQR spectra applied along the optical axis с up to the values of 500 kg/сm2 has been studied. A strong attenuation of NQR spectra intensity with increase in pressure on layered crystal package has been established. The unvaried multiplicity of resonance spectra indicates the absence of structural transformations in these layered crystals over the investigated range of temperatures and pressures.

  17. 105Pd NMR/NQR studies in UPd 2Al 3

    NASA Astrophysics Data System (ADS)

    Matsuda, K.; Kohori, Y.; Kohara, T.

    1999-01-01

    105Pd NMR and NQR measurements have been performed both in the normal and in the superconducting states for UPd 2Al 3. In the antiferromagnetically (AF) ordered state, the small internal field of about 3 kOe (at 4.2 K), which is perpendicular to the c-axis, appears below 14.5 K and does not decrease in the superconducting state. The nuclear spin-lattice relaxation rate, 1/ T1, in UPd 2Al 3 is nearly temperature, T, independent in the paramagnetic state up to 60 K, successively diverges at Nel temperature associated with the critical slowing down of U magnetic moments, and then decreases markedly in the AF ordered state. In the superconducting state, 1/ T1 decreases in proportion to T3 down to 0.4 K with no coherence peak just below TC, which indicates the occurrence of anisotropic superconductivity having line nodes in the superconducting energy gap.

  18. 35Cl NQR Study of Thermoactivated Motions of Nitro Groups in Picryl Chloride

    NASA Astrophysics Data System (ADS)

    Kyuntsel, Igor A.

    1996-06-01

    The temperature dependences of the 35Cl NQR frequency (ν), spin-lattice relaxation time (T1), and spin-spin relaxation time (T2) have been studied in 2,4,6-trinitrochlorobenzene (picryl chloride) from 77 K up to the melting point (354 K). The T1(T) curve exhibits a pronounced composite mimimum near 300 K which gives evidence for the reorientations of the two ortho-NO2 groups around their two-fold symmetry axes with the activation energies of 27.4 kJ mol - 1 and 31.2 kJ mol - 1. These values can be related to the ortho-NO2 groups having the twist angles of 33° and 81°, respectively (the crystal structure of picryl chloride is known). The T2(T) dependence exhibits interesting features, too: a deep minimum about 140 K and a new rapid decrease above 270 K.

  19. Combined Panofsky Quadrupole & Corrector Dipole

    SciTech Connect

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

    2007-07-02

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

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

    PubMed

    Perić, Berislav; Gautier, Régis; Pickard, Chris J; Bosiočić, Marko; Grbić, Mihael S; Požek, Miroslav

    2014-01-01

    Two hexanuclear niobium halide cluster compounds with a [Nb6X12](2+) (X=Cl, Br) diamagnetic cluster core, have been studied by a combination of experimental solid-state NMR/NQR techniques and PAW/GIPAW calculations. For niobium sites the NMR parameters were determined by using variable Bo field static broadband NMR measurements and additional NQR measurements. It was found that they possess large positive chemical shifts, contrary to majority of niobium compounds studied so far by solid-state NMR, but in accordance with chemical shifts of (95)Mo nuclei in structurally related compounds containing [Mo6Br8](4+) cluster cores. Experimentally determined δiso((93)Nb) values are in the range from 2,400 to 3,000 ppm. A detailed analysis of geometrical relations between computed electric field gradient (EFG) and chemical shift (CS) tensors with respect to structural features of cluster units was carried out. These tensors on niobium sites are almost axially symmetric with parallel orientation of the largest EFG and the smallest CS principal axes (Vzz and δ33) coinciding with the molecular four-fold axis of the [Nb6X12](2+) unit. Bridging halogen sites are characterized by large asymmetry of EFG and CS tensors, the largest EFG principal axis (Vzz) is perpendicular to the X-Nb bonds, while intermediate EFG principal axis (Vyy) and the largest CS principal axis (δ11) are oriented in the radial direction with respect to the center of the cluster unit. For more symmetrical bromide compound the PAW predictions for EFG parameters are in better correspondence with the NMR/NQR measurements than in the less symmetrical chlorine compound. Theoretically predicted NMR parameters of bridging halogen sites were checked by (79/81)Br NQR and (35)Cl solid-state NMR measurements. PMID:24581866

  1. Vibrational analysis of tevatron quadrupoles

    SciTech Connect

    Moore, C.D.

    1996-01-01

    There is motion of the beam in the Tevatron on various time scales from years (slow motion of the tunnel) to tenths of milliseconds (betatron tune motion). This paper will discuss a very restricted frequency range from a few Hertz to a few tens of Hertz. The assumption behind the analysis presented here is that the beam motion is due to transverse motion of Tevatron quadrupoles. The introduction of the low beta insertions in the Tevatron has necessitated the installation of remote monitoring sensors on the quadrupoles since the quadrupoles are strong and are located in regions where the beta functions are large. In general the magnet and support structures are mirror symmetric around the interaction points.

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

    SciTech Connect

    Reyes, A.P.; Ahrens, E.T.; Hammel, P.C.; Heffner, R.H.; Thompson, J.D.; Canfield, P.C.; Fisk, Z. ); Schirber, J.E. )

    1992-01-01

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

  3. Structural and Functional Investigation of Flavin Binding Center of the NqrC Subunit of Sodium-Translocating NADH:Quinone Oxidoreductase from Vibrio harveyi

    PubMed Central

    Bertsova, Yulia; Polovinkin, Vitaly; Gushchin, Ivan; Ishchenko, Andrii; Kovalev, Kirill; Mishin, Alexey; Kachalova, Galina; Popov, Alexander; Bogachev, Alexander; Gordeliy, Valentin

    2015-01-01

    Na+-translocating NADH:quinone oxidoreductase (NQR) is a redox-driven sodium pump operating in the respiratory chain of various bacteria, including pathogenic species. The enzyme has a unique set of redox active prosthetic groups, which includes two covalently bound flavin mononucleotide (FMN) residues attached to threonine residues in subunits NqrB and NqrC. The reason of FMN covalent bonding in the subunits has not been established yet. In the current work, binding of free FMN to the apo-form of NqrC from Vibrio harveyi was studied showing very low affinity of NqrC to FMN in the absence of its covalent bonding. To study structural aspects of flavin binding in NqrC, its holo-form was crystallized and its 3D structure was solved at 1.56 resolution. It was found that the isoalloxazine moiety of the FMN residue is buried in a hydrophobic cavity and that its pyrimidine ring is squeezed between hydrophobic amino acid residues while its benzene ring is extended from the protein surroundings. This structure of the flavin-binding pocket appears to provide flexibility of the benzene ring, which can help the FMN residue to take the bended conformation and thus to stabilize the one-electron reduced form of the prosthetic group. These properties may also lead to relatively weak noncovalent binding of the flavin. This fact along with periplasmic location of the FMN-binding domains in the vast majority of NqrC-like proteins may explain the necessity of the covalent bonding of this prosthetic group to prevent its loss to the external medium. PMID:25734798

  4. HANLE EFFECT FOR STELLAR DIPOLES AND QUADRUPOLES

    SciTech Connect

    Manso Sainz, R.; Gonzalez, M. J. Martinez

    2012-11-20

    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.

  5. Potential Antiferromagnetic Fluctuations in Hole-Doped Iron-Pnictide Superconductor Ba1-xKxFe2As2 Studied by 75As Nuclear Magnetic Resonance Measurement

    NASA Astrophysics Data System (ADS)

    Hirano, Masanori; Yamada, Yuji; Saito, Taku; Nagashima, Ryo; Konishi, Takehisa; Toriyama, Tatsuya; Ohta, Yukinori; Fukazawa, Hideto; Kohori, Yoh; Furukawa, Yuji; Kihou, Kunihiro; Lee, Chul-Ho; Iyo, Akira; Eisaki, Hiroshi

    2012-05-01

    We have performed 75As nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) meas urements on single-crystalline Ba1-xKxFe2As2 for x = 0.27{--}1. 75As nuclear quadruple resonance frequency (?Q) increases linearly with increasing x. The Knight shift K in the normal state shows Pauli paramagnetic behavior with a weak temperature T dependence. K increases gradually with increasing x. By contrast, the nuclear spin--lattice relaxation rate 1/T1 in the normal state has a strong T dependence, which indicates the existence of large antiferomagnetic (AF) spin fluctuations for all x's. The T dependence of 1/T1 shows a gaplike behavior below approximately 100 K for 0.6 < x < 0.9. This behaviors is well explained by the change in the band structure with the expansion of hole Fermi surfaces and the shrinkage and disappearance of electron Fermi surfaces at the Brillouin zone (BZ) with increasing x. The anisotropy of 1/T1, represented by the ratio of 1/T1ab to 1/T1c, is always larger than 1 for all x's, which indicates that stripe-type AF fluctuations are dominant in this system. The K in the superconducting (SC) state decreases, which corresponds to the appearance of spin-singlet superconductivity. The T dependence of 1/T1 in the SC state indicates a multiple-SC-gap feature. A simple two-gap model analysis shows that the larger superconducting gap gradually decreases with increasing x from 0.27 to 1 and a smaller gap decreases rapidly and nearly vanishes for x > 0.6 where electron pockets in BZ disappear.

  6. Calculation of nuclear quadrupole splitting in high- Tc superconductors

    SciTech Connect

    Saul, A.; Weissmann, M. )

    1990-09-01

    The electric-field gradient at the Cu site in YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} is calculated using the molecular orbitals obtained from a cluster calculation. The effects of the cluster geometry, cluster charge, and orbital occupation are studied, and the relation to nuclear-quadrupole-resonance frequencies is discussed. The same type of calculation is performed for clusters with Fe replacing Cu and compared with results of Moessbauer spectra.

  7. Nuclear Quadrupole Moments and Nuclear Shell Structure

    DOE R&D Accomplishments Database

    Townes, C. H.; Foley, H. M.; Low, W.

    1950-06-23

    Describes a simple model, based on nuclear shell considerations, which leads to the proper behavior of known nuclear quadrupole moments, although predictions of the magnitudes of some quadrupole moments are seriously in error.

  8. LCLS Undulator Quadrupole Fiducialization Plan

    SciTech Connect

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

    2010-11-24

    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.

  9. Quadrupole interactions in tetraoxoferrates (VI)

    NASA Astrophysics Data System (ADS)

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

    2013-05-01

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

  10. Quadrupole magnets for the SSC

    SciTech Connect

    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

    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.

  11. Sign-Selected Quadrupole Train

    SciTech Connect

    Bernstein, R.; NuTeV Collaboration

    1994-05-03

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2006-06-01

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

  13. Potential Antiferromagnetic Fluctuations in Hole-Doped Iron-Pnictide Superconductor Ba1-xKxFe2As2 Studied by 75As Nuclear Magnetic Resonance Measurement0.1143/JPSJ.81.054704

    SciTech Connect

    Hirano, Masanori; Yamada, Yuji; Saito, Taku; Nagashima, Ryo; Konishi, Takehisa; Toriyama, Tatsuya; Ohta, Yukinori; Fukazawa, Hideto; Kohori, Yoh; Furukawa, Yuji; Kihou, Kunihiro; Lee, Chul-Ho; Eisaki, Hiroshi

    2012-04-12

    We have performed 75As nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements on single-crystalline Ba1-xKxFe2As2 for x = 0.271. 75As nuclear quadruple resonance frequency (?Q) increases linearly with increasing x. The Knight shift K in the normal state shows Pauli paramagnetic behavior with a weak temperature T dependence. K increases gradually with increasing x. By contrast, the nuclear spinlattice relaxation rate 1/T1 in the normal state has a strong T dependence, which indicates the existence of large antiferomagnetic (AF) spin fluctuations for all x's. The T dependence of 1/T1 shows a gaplike behavior below approximately 100 K for 0.6 < x < 0.9. This behaviors is well explained by the change in the band structure with the expansion of hole Fermi surfaces and the shrinkage and disappearance of electron Fermi surfaces at the Brillouin zone (BZ) with increasing x. The anisotropy of 1/T1, represented by the ratio of 1/T1ab to 1/T1c, is always larger than 1 for all x's, which indicates that stripe-type AF fluctuations are dominant in this system. The K in the superconducting (SC) state decreases, which corresponds to the appearance of spin-singlet superconductivity. The T dependence of 1/T1 in the SC state indicates a multiple-SC-gap feature. A simple two-gap model analysis shows that the larger superconducting gap gradually decreases with increasing x from 0.27 to 1 and a smaller gap decreases rapidly and nearly vanishes for x > 0.6 where electron pockets in BZ disappear.

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

    SciTech Connect

    Peng, Shixiang Chen, Jia; Ren, Haitao; Zhao, Jie; Xu, Yuan; Zhang, Tao; Xia, Wenlong; Gao, Shuli; Wang, Zhi; Luo, Yuting; Guo, Zhiyu; Zhang, Ailing; Chen, Jia'er; University of Chinese Academy of Sciences, Beijing 100049

    2014-02-15

    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%.

  15. Analysis of 27Al- and 93Nb-NMR spectra of PrNb2Al20 single crystal

    NASA Astrophysics Data System (ADS)

    Kubo, Tetsuro; Kotegawa, Hisashi; Tou, Hideki; Higashinaka, Ryuji; Nakama, Akihiro; Aoki, Yuji; Sato, Hideyuki

    2016-02-01

    We report the results of 27Al- and 93Nb- nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements in PrNb2Al20 single crystals. The field angle dependence of the observed 93Nb-NMR lines for the single crystal at around 5 T and at 50 K is reproduced by a simulation using previously reported NQR parameters νQ,Nb ≈ 1.82 MHz and ηNb ≈ 0, while 27Al-NMR lines were not reproduce by the previously reported NQR parameters νQ,Al(3) ≈ 1.53 MHz and ηAl(3) ≈ 0.17. By reexamining and reconsidering the NMR and NQR lines for powder samples, we obtained a correct NQR parameters for Al(3) site to be νQ,Al(3),new ≈ 1 MHz and ηAl(3),new ≈ 0.4.

  16. Stabilized radio-frequency quadrupole

    DOEpatents

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

    1982-09-29

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

  17. Laced permanent magnet quadrupole drift tube magnets

    SciTech Connect

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

    1989-03-01

    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.

  18. Magnetic properties of ISABELLE superconducting quadrupoles

    SciTech Connect

    Willen, E; Engelmann, R; Greene, A F; Herrera, J; Jaeger, K; Kirk, H; Robins, K

    1981-01-01

    A number of superconducting quadrupole magnets have been constructed in the ISABELLE project during the past year. With these quadrupoles, it was intended to test construction techniques, magnet performance and measuring capability in an effort to arrive at a quadrupole design satisfactory for use in the storage ring accelerator. While these magnets are designed to have dimensions and field properties close to those needed for regular cell ISABELLE quadrupoles, no effort was made to make them identical to one another. This report details the performance characteristics of one of these magnets, MQ3005.

  19. 139La NQR and NMR studies of the structural phase transitions in La 1.8- xEu 0.2Sr xCuO 4

    NASA Astrophysics Data System (ADS)

    Suh, B. J.; Hammel, P. C.

    139La NQR and NMR relaxation measurements in the title compound have been used to investigate the dynamical properties of the structural phase transitions (SPT): HTT ? LTO and LTO ? LTT of lathanum cuprate. We present the data for thermodynamic fluctuations of critical modes in the vicinity of the SPT's which clearly reveal the character of each SPT and its dependence on doped hole concentration.

  20. Dissecting the Few-Femtosecond Dephasing Time of Dipole and Quadrupole Modes in Gold Nanoparticles Using Polarized Photoemission Electron Microscopy.

    PubMed

    Sun, Quan; Yu, Han; Ueno, Kosei; Kubo, Atsushi; Matsuo, Yasutaka; Misawa, Hiroaki

    2016-03-22

    Dipole and quadrupole modes are the two lowest orders of localized surface plasmon resonance (LSPR) eigenmodes in metallic nanoparticles. Of these two modes, the quadrupole mode is forbidden for symmetric metallic nanoparticles excited by linearly polarized light at normal incidence. Here, we demonstrate excitation of the quadrupole mode in symmetrical gold (Au) nanoblocks shined with s-polarized light at oblique incidence. In particular, we probe the near-field LSPR in Au nanoblocks using photoemission electron microscopy (PEEM) and find that at oblique incidence, the dipole and quadrupole modes can be selectively excited, in terms of near-field enhancement, by manipulating the light polarization state. More importantly, by time-resolved PEEM measurements, we experimentally demonstrate that the quadrupole mode in symmetrical Au nanoblocks has longer dephasing time than that of the dipole mode. PMID:26878248

  1. Image restoration using fast Fourier and wavelet transforms

    NASA Astrophysics Data System (ADS)

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

    1994-02-01

    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.

  2. A Vibrating Wire System For Quadrupole Fiducialization

    SciTech Connect

    Wolf, Zachary

    2010-12-13

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

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

    SciTech Connect

    Ki Deok Park; Guo, K.; Adebodun, F.; Chiu, M.L.; Sligar, S.G.; Oldfield, E. )

    1991-03-05

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

  4. Electrostatic quadrupoles for heavy-ion fusion

    SciTech Connect

    Seidl, P.; Faltens, A.

    1993-05-01

    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.

  5. Nuclear Quadrupole Moment of F

    SciTech Connect

    Martinez-Pinedo, Gabriel; Schwerdtfeger, Peter; Caurier, Etienne; Langanke, Karlheinz; Nazarewicz, Witold; Soehnel, Tilo

    2001-08-06

    The nuclear quadrupole moment (NQM) of the I{sup {pi}}=3/2{sup -} excited nuclear state of {sup 57}Fe at 14.41keV, important in Moessbauer spectroscopy, is determined from the large-scale nuclear shell-model calculations for {sup 54}Fe , {sup 57}Fe , and also from the electronic ab initio and density functional theory calculations including solid state and electron correlation effects for the molecules Fe(CO){sub 5} and Fe(C{sub 5}H{sub 5}){sub 2} . Both independent methods yield very similar results. The recommended value is 0.15(2)eb. The NQM of the isomeric 10+ in {sup 54}Fe has also been calculated. The new NQM values for {sup 54}Fe and {sup 57}Fe are consistent with the perturbed angular distribution data.

  6. Deformation effects in Giant Monopole Resonance

    NASA Astrophysics Data System (ADS)

    Kvasil, J.; Nesterenko, V. O.; Repko, A.; Bozik, D.; Kleinig, W.; Reinhard, P.-G.

    2015-02-01

    The isoscalar giant monopole resonance (GMR) in Samarium isotopes (from spherical 144Sm to deformed 148-154Sm) is investigated within the Skyrme random-phase- approximation (RPA) for a variety of Skyrme forces. The exact RPA and its separable version (SRPA) are used for spherical and deformed nuclei, respectively. Consistently with earlier investigations, the quadrupole deformation is shown to yield two effects: the GMR broadens and attains a two-peak structure due to the coupling with the quadrupole giant resonance.

  7. An innovative method for the non-destructive identification of photodegradation products in solid state: 1H-14N NMR-NQR and DFT/QTAIM study of photodegradation of nifedipine (anti-hypertensive) to nitrosonifedipine (potential anti-oxidative).

    PubMed

    Latosi?ska, J N; Latosi?ska, M; Seliger, J; Zagar, V

    2012-08-30

    Stability of the antihypertensive drug nifedipine (NIF) has been studied experimentally in solid state by (1)H-(14)N NMR-NQR double resonance (NQDR) and theoretically by the Density Functional Theory (DFT). Photodegradation of NIF to its metabolite in vivo nitrosonifedipine, NO-NIF (antioxidative agent) upon long term daylight exposure was detected and the changes in the molecular structure of NIF were analysed. The photoconversion of NIF to NO-NIF in solid was found to be accompanied with the electron density redistribution at nitrogen sites (NH to N and NO(2) to NO) and proved to be successfully detected with identification of photoproducts by (1)H-(14)N NQDR and DFT methods. The increase in the e(2)qQ/h and ? describing EFG tendency towards non-spherical symmetry was significantly greater upon the reduction of NO(2) site than upon hydrogen abstraction from NH site. The level of sensitivity of detection of the photodegradation product was about 1% of the original sample. The Quantum Theory of Atoms in Molecules (QTAIM) analysis has been found useful in predicting photoreactive sites in the molecules and finding the explanation of differences in reactivity between parent NIF and its photoproduct NO-NIF. Using NIF as a model, this study demonstrates the suitability of NQDR supported by DFT for non-destructive determination of the photodegradation products in solid state. PMID:22609436

  8. DIPOLE AND QUADRUPOLE SORTING FOR THE SNS RING.

    SciTech Connect

    RAPARIA,D.FEDOTOV,A.LEE,Y.Y.ET AL.

    2004-07-05

    The Spallation Neutron Source (SNS) accumulator ring is a high intensity ring and must have low uncontrolled losses for hands on maintenance. To achieve these low losses one needs very tight tolerance. These tight tolerances have been achieved through shimming the magnets and sorting. Dipoles are solid core magnets and had very good field quality but magnet to magnet variation were sorted out according to ITF, since all the dipole are powered with one power supply. Typically, sorting is done to minimize linear effects in beam dynamics. Here, sorting of quadrupoles was done according to a scheme, which allows reducing unwanted strength of nonlinear resonances. As a result, the strength of sextupole resonances for our base line tune-box was strongly reduced which was confirmed by a subsequent beam dynamics simulation.

  9. Nuclear electric quadrupole induction of atomic polarization

    SciTech Connect

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

    1986-11-24

    Precessing nuclear quadrupole moments are observed to induce oscillating electric dipole moments in neighboring atoms. The /sup 35/Cl nuclei of a single crystal of NaClO/sub 3/ placed between the plates of a capacitor are excited into precession by a rf pulse. After the pulse, the electric polarization induced by the chlorine nuclear quadrupole moments produces a voltage across the capacitor, which is amplified with a dc SQUID. This technique provides information on the location and polarizability of atoms near nuclear quadrupole moments in noncentrosymmetric crystals.

  10. Giant multipole resonances: perspectives after ten years

    SciTech Connect

    Bertrand, F.E.

    1980-01-01

    Nearly ten years ago evidence was published for the first of the so-called giant multipole resonances, the giant quadrupole resonance. During the ensuing years research in this field has spread to many nuclear physics laboratories throughout the world. The present status of electric giant multipole resonances is reviewed. 24 figures, 1 table.

  11. Nonuniform radiation damage in permanent magnet quadrupoles

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

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

  12. Klystron having electrostatic quadrupole focusing arrangement

    DOEpatents

    Maschke, Alfred W. (East Moriches, NY)

    1983-08-30

    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.

  13. Nonuniform radiation damage in permanent magnet quadrupoles.

    PubMed

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

    2014-08-01

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

  14. Klystron having electrostatic quadrupole focusing arrangement

    DOEpatents

    Maschke, A.W.

    1983-08-30

    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.

  15. Nonuniform radiation damage in permanent magnet quadrupoles

    SciTech Connect

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

    2014-08-15

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

  16. Miniature quadrupole mass spectrometer array

    NASA Technical Reports Server (NTRS)

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

    1997-01-01

    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.

  17. Miniature quadrupole mass spectrometer array

    NASA Technical Reports Server (NTRS)

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

    1998-01-01

    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.

  18. Integrally formed radio frequency quadrupole

    DOEpatents

    Abbott, Steven R.

    1989-01-01

    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.

  19. Permanent magnet edge-field quadrupole

    DOEpatents

    Tatchyn, R.O.

    1997-01-21

    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.

  20. Permanent magnet edge-field quadrupole

    DOEpatents

    Tatchyn, Roman O. (Mountain View, CA)

    1997-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

    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

    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.

  2. "Fast Excitation" CID in Quadrupole Ion Trap Mass Spectrometer

    SciTech Connect

    Murrell, J.; Despeyroux, D.; Lammert, Stephen {Steve} A; Stephenson Jr, James {Jim} L; Goeringer, Doug

    2003-01-01

    Collision-induced dissociation (CID) in a quadrupole ion trap mass spectrometer is usually performed by applying a small amplitude excitation voltage at the same secular frequency as the ion of interest. Here we disclose studies examining the use of large amplitude voltage excitations (applied for short periods of time) to cause fragmentation of the ions of interest. This process has been examined using leucine enkephalin as the model compound and the motion of the ions within the ion trap simulated using ITSIM. The resulting fragmentation information obtained is identical with that observed by conventional resonance excitation CID. ''Fast excitation'' CID deposits (as determined by the intensity ratio of the a{sub 4}/b{sub 4} ion of leucine enkephalin) approximately the same amount of internal energy into an ion as conventional resonance excitation CID where the excitation signal is applied for much longer periods of time. The major difference between the two excitation techniques is the higher rate of excitation (gain in kinetic energy) between successive collisions with helium atoms with ''fast excitation'' CID as opposed to the conventional resonance excitation CID. With conventional resonance excitation CID ions fragment while the excitation voltage is still being applied whereas for ''fast excitation'' CID a higher proportion of the ions fragment in the ion cooling time following the excitation pulse. The fragmentation of the (M + 17H){sup 17+} of horse heart myoglobin is also shown to illustrate the application of ''fast excitation'' CID to proteins.

  3. SUPERCONDUCTING QUADRUPOLE ARRAYS FOR MULTIPLE BEAM TRANSPORT

    SciTech Connect

    Rainer Meinke Carl Goodzeit Penny Ball Roger Bangerter

    2003-10-01

    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.

  4. Induced CMB quadrupole from pointing offsets

    SciTech Connect

    Moss, Adam; Scott, Douglas; Sigurdson, Kris E-mail: dscott@phas.ubc.ca

    2011-01-01

    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 Y{sub 2,?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.

  5. Heavy ion plasma confinement in an RF quadrupole trap

    NASA Technical Reports Server (NTRS)

    Schermann, J.; Major, F. G.

    1971-01-01

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

  6. A Tandem-electrostatic-quadrupole for accelerator-based BNCT

    NASA Astrophysics Data System (ADS)

    Kreiner, A. J.; Kwan, J. W.; Burln, A. A.; Di Paolo, H.; Henestroza, E.; Minsky, D. M.; Valda, A. A.; Debray, M. E.; Somacal, H.

    2007-08-01

    A project to develop a Tandem-electrostatic-quadrupole (TESQ) accelerator for accelerator-based boron neutron capture therapy (AB-BNCT) is described. A folded Tandem, with 1.25 MV terminal voltage, combined with an electrostatic quadrupole (ESQ) chain is being proposed. The project goal is a machine capable of delivering 30 mA of 2.5 MeV protons to be used in conjunction with a neutron production target based on the 7Li(p, n)7Be reaction slightly beyond its resonance at 2.25 MeV. This machine is conceptually shown to be capable of accelerating a 30 mA proton beam to 2.5 MeV. These are the specifications needed to produce sufficiently intense and clean epithermal neutron beams, based on the 7Li(p, n)7Be reaction, to perform BNCT treatment for deep-seated tumors in less than an hour. This electrostatic machine is the technologically simplest and cheapest solution for optimized AB-BNCT.

  7. The Large Quadrupole of Water Molecules

    SciTech Connect

    Niu, Shuqiang; Tan, Ming-Liang; Ichiye, Toshhiko

    2011-04-07

    Many quantum mechanical calculations indicate water molecules in the gas and liquid phase have much larger quadrupole moments than any of the common site models of water for computer simulations. Here, comparisons of multipoles from quantum mechanical/molecular mechanical (QM/MM) calculations at the MP2/aug-cc-pVQZ level on a B3LYP/aug-cc-pVQZ level geometry of a waterlike cluster and from various site models show that the increased square planar quadrupole can be attributed to the p-orbital character perpendicular to the molecular plane of the highest occupied molecular orbital as well as a slight shift of negative charge toward the hydrogens. The common site models do not account for the p-orbital type electron density and fitting partial charges of TIP4P- or TIP5P-type models to the QM/MM dipole and quadrupole give unreasonable higher moments. Furthermore, six partial charge sites are necessary to account reasonably for the large quadrupole, and polarizable site models will not remedy the problem unless they account for the p-orbital in the gas phase since the QM calculations show it is present there too. On the other hand, multipole models by definition can use the correct multipoles and the electrostatic potential from the QM/MM multipoles is much closer than that from the site models to the potential from the QM/MM electron density. Finally, Monte Carlo simulations show that increasing the quadrupole in the soft-sticky dipole-quadrupole-octupole multipole model gives radial distribution functions that are in good agreement with experiment

  8. Levitated spinning graphene flakes in an electric quadrupole ion trap

    NASA Astrophysics Data System (ADS)

    Kane, B. E.

    2010-09-01

    A method is described for levitating micron-sized few-layer graphene flakes in an electric quadrupole ion trap. Starting from a liquid suspension containing graphene, charged flakes are injected into the trap using the electrospray ionization technique and are probed optically. At micro-torr pressures, torques from circularly polarized light cause the levitated particles to rotate at frequencies >1MHz , which can be inferred from modulation of light scattering off the rotating flake when an electric field resonant with the rotation rate is applied. Possible applications of these techniques will be presented, both to fundamental measurements of the mechanical and electronic properties of graphene and to new approaches to graphene crystal growth, modification, and manipulation.

  9. Tunable high-gradient permanent magnet quadrupoles

    NASA Astrophysics Data System (ADS)

    Shepherd, B. J. A.; Clarke, J. A.; Marks, N.; Collomb, N. A.; Stokes, D. G.; Modena, M.; Struik, M.; Bartalesi, A.

    2014-11-01

    A novel type of highly tunable permanent magnet (PM) based quadrupole has been designed by the ZEPTO collaboration. A prototype of the design (ZEPTO-Q1), intended to match the specification for the CLIC Drive Beam Decelerator, was built and magnetically measured at Daresbury Laboratory and CERN. The prototype utilises two pairs of PMs which move in opposite directions along a single vertical axis to produce a quadrupole gradient variable between 15 and 60 T/m. The prototype meets CLIC's challenging specification in terms of the strength and tunability of the magnet.

  10. The nuclear electric quadrupole moment of copper.

    PubMed

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

    2014-06-21

    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

  11. Electric quadrupole transition probabilities for atomic lithium

    SciTech Connect

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

    2014-05-15

    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 HartreeFock 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.

  12. Magnetic Measurement Results of the LCLS Undulator Quadrupoles

    SciTech Connect

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

    2011-08-18

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

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

    NASA Astrophysics Data System (ADS)

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

    1986-07-01

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

  14. Simple expressions of the nuclear relaxation rate enhancement due to quadrupole nuclei in slowly tumbling molecules

    NASA Astrophysics Data System (ADS)

    Fries, Pascal H.; Belorizky, Elie

    2015-07-01

    For slowly tumbling entities or quasi-rigid lattices, we derive very simple analytical expressions of the quadrupole relaxation enhancement (QRE) of the longitudinal relaxation rate R1 of nuclear spins I due to their intramolecular magnetic dipolar coupling with quadrupole nuclei of arbitrary spins S ≥ 1. These expressions are obtained by using the adiabatic approximation for evaluating the time evolution operator of the quantum states of the quadrupole nuclei S. They are valid when the gyromagnetic ratio of the spin S is much smaller than that of the spin I. The theory predicts quadrupole resonant peaks in the dispersion curve of R1 vs magnetic field. The number, positions, relative intensities, Lorentzian shapes, and widths of these peaks are explained in terms of the following properties: the magnitude of the quadrupole Hamiltonian and the asymmetry parameter of the electric field gradient (EFG) acting on the spin S, the S-I inter-spin orientation with respect to the EFG principal axes, the rotational correlation time of the entity carrying the S-I pair, and/or the proper relaxation time of the spin S. The theory is first applied to protein amide protons undergoing dipolar coupling with fast-relaxing quadrupole 14N nuclei and mediating the QRE to the observed bulk water protons. The theoretical QRE agrees well with its experimental counterpart for various systems such as bovine pancreatic trypsin inhibitor and cartilages. The anomalous behaviour of the relaxation rate of protons in synthetic aluminium silicate imogolite nano-tubes due to the QRE of 27Al (S = 5/2) nuclei is also explained.

  15. Simple expressions of the nuclear relaxation rate enhancement due to quadrupole nuclei in slowly tumbling molecules.

    PubMed

    Fries, Pascal H; Belorizky, Elie

    2015-07-28

    For slowly tumbling entities or quasi-rigid lattices, we derive very simple analytical expressions of the quadrupole relaxation enhancement (QRE) of the longitudinal relaxation rate R1 of nuclear spins I due to their intramolecular magnetic dipolar coupling with quadrupole nuclei of arbitrary spins S ? 1. These expressions are obtained by using the adiabatic approximation for evaluating the time evolution operator of the quantum states of the quadrupole nuclei S. They are valid when the gyromagnetic ratio of the spin S is much smaller than that of the spin I. The theory predicts quadrupole resonant peaks in the dispersion curve of R1 vs magnetic field. The number, positions, relative intensities, Lorentzian shapes, and widths of these peaks are explained in terms of the following properties: the magnitude of the quadrupole Hamiltonian and the asymmetry parameter of the electric field gradient (EFG) acting on the spin S, the S-I inter-spin orientation with respect to the EFG principal axes, the rotational correlation time of the entity carrying the S-I pair, and/or the proper relaxation time of the spin S. The theory is first applied to protein amide protons undergoing dipolar coupling with fast-relaxing quadrupole (14)N nuclei and mediating the QRE to the observed bulk water protons. The theoretical QRE agrees well with its experimental counterpart for various systems such as bovine pancreatic trypsin inhibitor and cartilages. The anomalous behaviour of the relaxation rate of protons in synthetic aluminium silicate imogolite nano-tubes due to the QRE of (27)Al (S = 5/2) nuclei is also explained. PMID:26233122

  16. Interference of gadolinium on the measurement of selenium in human serum by inductively coupled plasma-quadrupole mass spectrometry.

    PubMed

    Walter, Alan; Nelms, Simon; Harrington, Chris F; Taylor, Andrew

    2011-03-01

    Selenium is an important clinical biomarker of nutritional status; however, the occurrence of gadolinium in a patient's serum as a result of the contrast agents used during magnetic resonance imaging investigations, results in a significant positive bias in its measurement by inductively coupled plasma-quadrupole mass spectrometry. PMID:21355013

  17. Skew quadrupole errors in the RHIC IR triplets

    SciTech Connect

    Tepikian, S.; Peggs, S.

    1993-12-31

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

  18. Tevatron low-beta quadrupole triplet interconnects

    SciTech Connect

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

    1992-04-01

    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.

  19. Nontrivial zeros of the Racah quadrupole invariant

    SciTech Connect

    Brudno, S.; Louck, J.D.

    1985-06-01

    It is shown that a class of nontrivial zeros of the Racah quadrupole invariant operator is given by two orbits of the group action of an infinite discrete subgroup of the proper two-dimensional Lorentz group SO(1,1) on the hyperbola 4x/sup 2/-3y/sup 2/ = (11)/(4) .

  20. Closed orbit response to quadrupole strength variation

    SciTech Connect

    Wolski, Andrzej; Zimmermann, Frank

    2004-01-20

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

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

    NASA Astrophysics Data System (ADS)

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

    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.

  2. Heavy ion excitation and photon decay of giant resonances

    SciTech Connect

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

    1983-01-01

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

  3. Thermal analysis of SC quadrupoles in accelerator interaction regions

    SciTech Connect

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

    2006-09-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

  5. Search for a Magnetic-Field Dependence of the Interaction of the Nuclear Quadrupole Moment with the Electric-Field Gradient

    NASA Astrophysics Data System (ADS)

    Filsinger, B.; Gutsche, P.; Haeberlen, U.; Weiden, N.

    1997-04-01

    It is argued that the nuclear quadrupole-electric field gradient (EFG) interaction is, in principle, dependent on the presence of a magnetic fieldB. A rough estimate of the size of this effect yields 10-4in fields up to 10 T. However, if the site symmetry of the nucleus in question includes time-reversal symmetry, the linear dependence of the EFG onBvanishes. In diamagnetic compounds, time-reversal symmetry is violated only by the presence of nuclear spins. In such compounds, the dominant dependence of the EFG onBshould be quadratic and should be described by a fourth-rank tensor. In ferro- and antiferromagnetic compounds time-reversal symmetry is strongly violated and a linear dependence of the EFG onB, described by a third-rank tensor, is expected. A search for a magnetic field dependence of the EFG was carried out by measuring the quadrupole coupling constants (QCCs) of the27Al and14N nuclei in corundum and sodium nitroprusside (SNP) by pure NQR, and by NMR in fields of 6.3 and 11 T. These diamagnetic compounds were selected because previous measurements, done in different fields, yielded differing results for the QCCs. A new technique for measuring QCCs by NMR is introduced that circumvents the necessity of precisely orienting the sample crystals. For the QCCs of both the27Al and14N nuclei in corundum and SNP, respectively, a precision of distinctly better than 10-4is reached. The results obtained in 0, 6.3, and 11 T fields fully agree with each other which means that, in fields up to 11 T, any possible field dependence of the QCCs is smaller than 10-4. These results confirm that in diamagnetic compounds a linear dependence of QCCs onBis largely suppressed.

  6. LARP Long Nb3Sn Quadrupole Design.

    SciTech Connect

    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

    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.

  7. LARP Long Nb3Sn Quadrupole Design

    SciTech Connect

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

    2008-06-01

    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.

  8. 15 T And Beyond - Dipoles and Quadrupoles

    SciTech Connect

    Sabbi, GianLuca

    2008-05-19

    Starting with the invention of the cyclotron by Lawrence, accelerator-based experiments have been the primary source of new discoveries in particle physics. In order to progress toward higher energy and luminosity, higher field magnets are required. R&D programs are underway to take advantage of new developments in superconducting materials, achieve better efficiency and simplify magnet fabrication while preserving accelerator-class field quality. A review of recent progress on high field dipole and quadrupole magnets is presented.

  9. Muon cooling in a quadrupole magnet channel

    SciTech Connect

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

    2007-10-01

    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.

  10. Superconducting sextupoles and trim quadrupoles for RHIC

    SciTech Connect

    Thompson, P.; Anerella, M.; Ganetis, G.

    1995-05-01

    RHIC requires 288 sextupole and 72 trim quadrupole magnets. These iron poletip superconducting magnets have been constructed by Everson Electric Co. Room temperature field measurements have been completed for 75% of these magnets with acceptable results. Approximately 15% of them have been tested at 4.6 K for maximum (quench) current. The quench performance for the early magnets was good and improved to excellent during the production run. These magnets have more than 100% margin at quench.

  11. Materials Characterisation by Nuclear Quadrupole Interaction

    NASA Astrophysics Data System (ADS)

    Bastow, T. J.

    1994-02-01

    The power of solid state NMR to characterise solids by determining the nuclear quadrupole coupling of the constituent nuclei is demonstrated for a number of com pounds of current interest in a materials science laboratory. Recent results are presented for the nuclei 17O , 23Na, 27Al, 39K, 71Ga, 91Zr, 93Nb, and 139La. These were derived using a variety of FT NMR techniques including static, magic angle spinning and frequency stepped spin echo NMR spectroscopy.

  12. Microfluidic quadrupole and floating concentration gradient

    PubMed Central

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

    2014-01-01

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

  13. AGS-booster orbit and resonance correction

    SciTech Connect

    Milutinovic, J.; Ruggiero, A.G.; Tepikian, S.; Weng, W.T.

    1989-01-01

    A large tune-spread due to space charge and strong random eddy current sextupoles exists at injection in the AGS-Booster. As a result, particles in the beam may cross several imperfection resonances that can be caused by random magnet errors. The correction scheme proposed deals with four half-integer stopband resonances, four third order sextupole induced resonances and both the sum and difference linear coupling resonances. All of these resonances can have a chance to be swept through by the beam during injection bunching and the early stage of acceleration. A system of correctors involving skew quadrupoles, trim quadrupoles and sextupoles is described with the capability of correcting all the major resonances involved, simultaneously. Also a closed orbit correction scheme is described which requires, to be effective, a cascade of local 3-magnet bumps. Several magnet imperfections and survey misalignment errors are investigated. 7 refs., 3 figs.

  14. Analysis of intense beam instability in a general quadrupole focusing channel with image charge effect

    NASA Astrophysics Data System (ADS)

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

    2016-02-01

    The stability properties of transverse envelopes of mismatched intense continuous charge particle beam propagating in a general quadrupole focusing channel have been investigated in the presence of image charge effect due to a cylindrical conducting pipe. Phase shifts and growth factors of the envelope oscillations in the case of instability are calculated by numerical evaluation of the eigenvalues of linearly perturbed envelope equations for small deviations from the matched beam conditions. A detailed study on the region of instability and its dependence on the system parameters like occupancy of the quadrupole focusing field, syncopation factor, zero current phase advance, beam intensity etc. have been carried out. It has been found that the strength and regions of envelope instability due to the lattice and confluent resonances in the parametric space are affected by the presence of image charge.

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

    SciTech Connect

    Li Leping; Gu Quanli; Knee, J. L.; Wright, J. D.; DiSciacca, J. M.; Morgan, T. J.

    2008-03-15

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

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

    SciTech Connect

    Lepers, M.; Dulieu, O.; Kokoouline, V.

    2010-10-15

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

    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.

  18. Matrix methods for the calculation of stability diagrams in quadrupole mass spectrometry.

    PubMed

    Konenkov, N V; Sudakov, M; Douglas, D J

    2002-06-01

    The theory of the computer calculation of the stability of ion motion in periodic quadrupole fields is considered. A matrix approach for the numerical solution of the Hill equation and examples of calculations of stability diagrams are described. The advantage of this method is that it can be used for any periodic waveform. The stability diagrams with periodic rectangular waveform voltages are calculated with this approach. Calculations of the conventional stability diagram of the 3-D ion trap and the first six regions of stability of a mass filter with this method are presented. The stability of the ion motion for the case of a trapping voltage with two or more frequencies is also discussed. It is shown that quadrupole excitation with the rational angular frequency omega = Nomega/P (where N, P are integers and omega is the angular frequency of the trapping field) leads to splitting of the stability diagram along iso-beta lines. Each stable region of the unperturbed diagram splits into P stable bands. The widths of the unstable resonance lines depend on the amplitude of the auxiliary voltage and the frequency. With a low auxiliary frequency splitting of the stability diagram is greater near the boundaries of the unperturbed diagram. It is also shown that amplitude modulation of the trapping RF voltage by an auxiliary signal is equivalent to quadrupole excitation with three frequencies. The effect of modulation by a rational frequency is similar to the case of quadrupole excitation, although splitting of the stability diagram differs to some extent. The methods and results of these calculations will be useful for studies of higher stability regions, resonant excitation, and non-sinusoidal trapping voltages. PMID:12056561

  19. Spatially periodic radio-frequency quadrupole focusing linac

    NASA Astrophysics Data System (ADS)

    Kolomiets, A. A.; Plastun, A. S.

    2015-12-01

    The new design for a spatially periodical rf quadrupole focusing linac is proposed. It consists of accelerating gaps formed between conventional cylindrical drift tubes, between drift tubes and rf quadrupoles with nonzero axial potential, and inside these rf quadrupoles, formed in the same way as in a conventional radio-frequency quadrupole (RFQ) linac with modulated electrodes. Such a combination provides both higher energy gain rate than conventional RFQ and stability of transverse motion for ion beams. The structure can be designed using various combinations of quadrupoles and drift tubes. Some options are considered in the paper using the smooth approximation method and computer simulation of beam dynamics. Transverse stability of particles has been studied. The proposed structure can provide suppression of rf defocusing effects on transverse beam dynamics. Some limitations of the spatially periodic rf quadrupole structure are mentioned.

  20. Mechanism of metallization and superconductivity suppression in YBa2(Cu0.97 Zn0.03)3 O6.92 revealed by 67Zn NQR

    NASA Astrophysics Data System (ADS)

    Pelc, D.; Poek, M.; Despoja, V.; Sunko, D. K.

    2015-08-01

    We measure the nuclear quadrupole resonance signal on the Zn site in nearly optimally doped YBa2Cu3O6.92, when Cu is substituted by 3% of isotopically pure 67Zn. We observe that Zn creates large insulating islands, confirming two earlier conjectures: that doping provokes an orbital transition in the CuO2 plane, which is locally reversed by Zn substitution, and that the islands are antiferromagnetic. Also, we find that the Zn impurity locally induces a breaking of the D4 symmetry. Cluster and DFT calculations show that the D4 symmetry breaking is due to the same partial lifting of degeneracy of the nearest-neighbor oxygen sites as in the LTT transition in {La}{}2-xBaxCuO4, similarly well-known to strongly suppress superconductivity (SC). These results show that in-plane oxygen 2p5 orbital configurations are principally involved in the metallicity and SC of all high-Tc cuprates, and provide a qualitative symmetry-based constraint on the SC mechanism.

  1. ANALYTICAL SOLUTIONS OF SINGULAR ISOTHERMAL QUADRUPOLE LENS

    SciTech Connect

    Chu Zhe; Lin, W. P.; Yang Xiaofeng E-mail: linwp@shao.ac.cn

    2013-06-20

    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.

  2. Noise reduction in negative-ion quadrupole mass spectrometry

    DOEpatents

    Chastagner, P.

    1993-04-20

    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.

  3. Magnetic mirror structure for testing shell-type quadrupole coils

    SciTech Connect

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

    2009-10-01

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

  4. Multi-Pass Quadrupole Mass Analyzer

    NASA Technical Reports Server (NTRS)

    Prestage, John D.

    2013-01-01

    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.

  5. Hybrid rare earth quadrupole drift tube magnets

    SciTech Connect

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

    1985-05-01

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

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

    SciTech Connect

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

    1996-12-12

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

  7. Study of nuclear quadrupole interactions and quadrupole Raman processes of 69Ga and 71Ga in a ?-Ga 2O 3:Cr 3+ single crystal

    NASA Astrophysics Data System (ADS)

    Yeom, Tae Ho; Lim, Ae Ran

    2009-10-01

    Nuclear magnetic resonance (NMR) data and the spin-lattice relaxation times, T1, of 69Ga and 71Ga nuclei in a ?-Ga 2O 3:Cr 3+ single crystal were obtained using FT NMR spectrometry. Four sets of NMR spectra for 69Ga ( I = 3/2) and 71Ga ( I = 3/2) were obtained in the crystallographic planes. The 69Ga and 71Ga nuclei each had two chemically inequivalent Ga I and Ga II centers. Each of the 69Ga and 71Ga 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 69Ga I, 69Ga II, 71Ga I, and 71Ga II centers in a ?-Ga 2O 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 69Ga and 71Ga relaxation rates were consistent with Raman processes, as T1-1 ? T2. 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.

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

    PubMed

    Yeom, Tae Ho; Lim, Ae Ran

    2009-10-01

    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

  9. Giant resonances - why protons

    SciTech Connect

    Bertrand, F.E.

    1983-01-01

    Protons excite giant resonances, indeed the systematic establishment of the existence of the first non-dipole giant resonance, the giant quadrupole resonance (GQR) came from the use of inelastic proton scatering. The question addressed, however, is how does the proton stack up for such studies when compared to the use of other hadronic probes. What can we uniquely learn about giant multipole resonances using proton scattering. Specifically, results from (p, p'), and (..cap alpha.., ..cap alpha..') and (/sup 16/o, /sup 16/O') reactions are compared as regards excitation of giant multipole resonances, and some of the advantages and disadvantages to the use of each probe are detailed. It is hoped to leave the impression that it is in the determination of resonance multipolarity by comparison of measured and calculated angular distributions that the proton is a winner. It is shown what we are learning about high-L (L > 3) giant resonances using the (p, p') angular distribution. This discussion will generally be limited to isoscalar electric (i.e., T = 0, S = 0) giant resonances.

  10. Field stabilization studies for a radio frequency quadrupole accelerator

    NASA Astrophysics Data System (ADS)

    Gaur, R.; Kumar, V.

    2014-07-01

    The Radio Frequency Quadrupole (RFQ) linear accelerator is an accelerator that efficiently focuses, bunches and accelerates a high intensity DC beam from an ion source, for various applications. Unlike other conventional RF linear accelerators, the electromagnetic mode used for its operation is not the lowest frequency mode supported by the structure. In a four vane type RFQ, there are several undesired electromagnetic modes having frequency close to that of the operating mode. While designing an RFQ accelerator, care must be taken to ensure that the frequencies of these nearby modes are sufficiently separated from the operating mode. If the undesired nearby modes have frequencies close to the operating mode, the electromagnetic field pattern in the presence of geometrical errors will not be stabilized to the desired field profile, and will be perturbed by the nearby modes. This will affect the beam dynamics and reduce the beam transmission. In this paper, we present a detailed study of the electromagnetic modes supported, which is followed by calculations for implementation of suitable techniques to make the desired operating mode stable against mixing with unwanted modes for an RFQ being designed for the proposed Indian Spallation Neutron Source (ISNS) project at Raja Ramanna Centre for Advanced Technology, Indore. Resonant coupling scheme, along with dipole stabilization rods has been proposed to increase the mode separation. The paper discusses the details of a generalized optimization procedure that has been used for the design of mode stabilization scheme.

  11. Stabilized operation of the improvement of the Spallation Neutron Source (SNS) radio-frequency quadrupole (RFQ)

    SciTech Connect

    Kim, Sang-Ho; Aleksandrov, Alexander V; Crofford, Mark T; Galambos, John D; Gibson, Paul E; Hardek, Thomas W; Henderson, Stuart D; Kang, Yoon W; Kasemir, Kay; Peters, Charles C; Thompson, David H; Stockli, Martin P; Williams, Derrick C

    2010-01-01

    The Spallation Neutron Source (SNS) radio-frequency quadrupole (RFQ) had resonance control instabilities at duty factors higher than approximately four percent. Systematic investigations have been carried out to understand the cause of the instability and to ensure the operational stability of the RFQ. The most critical source of the instability is revealed to be an interaction between hydrogen released by beam bombardments and the RFQ RF field resulting in a discharge, which consumes additional RF power and could cause the RFQ to operate in an unstable region. This paper reports improvement of the SNS RFQ operational stability based on the findings during the SNS operation.

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

    NASA Astrophysics Data System (ADS)

    Asaji, Tetsuo

    2013-05-01

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

  13. Electrostatic quadrupole focused particle accelerating assembly with laminar flow beam

    DOEpatents

    Maschke, A.W.

    1984-04-16

    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.

  14. Feedback damper system for quadrupole oscillations after transition at RHIC.

    SciTech Connect

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

    2008-06-23

    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.

  15. Differentially pumped dual linear quadrupole ion trap mass spectrometer

    SciTech Connect

    Owen, Benjamin C.; Kenttamaa, Hilkka I.

    2015-10-20

    The present disclosure provides a new tandem mass spectrometer and methods of using the same for analyzing charged particles. The differentially pumped dual linear quadrupole ion trap mass spectrometer of the present disclose includes a combination of two linear quadrupole (LQIT) mass spectrometers with differentially pumped vacuum chambers.

  16. Electrostatic quadrupole focused particle accelerating assembly with laminar flow beam

    DOEpatents

    Maschke, Alfred W. (East Moriches, NY)

    1985-01-01

    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.

  17. Commissioning a Vibrating Wire System for Quadrupole Fiducialization

    SciTech Connect

    Levashov, Michael Y

    2010-12-03

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

  18. Double-photoionization of helium including quadrupole radiation effects

    SciTech Connect

    Colgan, James; Ludlow, J A; Lee, Teck - Ghee; Pindzola, M S; Robicheaux, F

    2009-01-01

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

  19. Supersonic Quadrupole Noise Theory for High-Speed Helicopter Rotors

    NASA Technical Reports Server (NTRS)

    Farassat, F.; Brentner, Kenneth S.

    1997-01-01

    High-speed helicopter rotor impulsive noise prediction is an important problem of aeroacoustics. The deterministic quadrupoles have been shown to contribute significantly to high-speed impulsive (HSI) noise of rotors, particularly when the phenomenon of delocalization occurs. At high rotor-tip speeds, some of the quadrupole sources lie outside the sonic circle and move at supersonic speed. Brentner has given a formulation suitable for efficient prediction of quadrupole noise inside the sonic circle. In this paper, we give a simple formulation based on the acoustic analogy that is valid for both subsonic and supersonic quadrupole noise prediction. Like the formulation of Brentner, the model is exact for an observer in the far field and in the rotor plane and is approximate elsewhere. We give the full analytic derivation of this formulation in the paper. We present the method of implementation on a computer for supersonic quadrupoles using marching cubes for constructing the influence surface (Sigma surface) of an observer space- time variable (x; t). We then present several examples of noise prediction for both subsonic and supersonic quadrupoles. It is shown that in the case of transonic flow over rotor blades, the inclusion of the supersonic quadrupoles improves the prediction of the acoustic pressure signature. We show the equivalence of the new formulation to that of Brentner for subsonic quadrupoles. It is shown that the regions of high quadrupole source strength are primarily produced by the shock surface and the flow over the leading edge of the rotor. The primary role of the supersonic quadrupoles is to increase the width of a strong acoustic signal.

  20. RADIATION RESISTANT HTS QUADRUPOLES FOR RIA.

    SciTech Connect

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

    2004-10-03

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

  1. An improved integrally formed radio frequency quadrupole

    DOEpatents

    Abbott, S.R.

    1987-10-05

    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.

  2. Roll measurement of Tevatron dipoles and quadrupoles

    SciTech Connect

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

    2006-09-01

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

  3. Optical tomography inside quadrupole ion traps

    SciTech Connect

    Garrett, A.W.; Nogar, N.S.; Hemberger, P.H.

    1995-12-31

    Operation of a quadrupole ion-trap mass spectrometer (ITMS) depends on details of ion motion in the trap such as spatial and velocity distribution, effects of gas pressure and ion density, the RF drive frequency, phase and amplitude, and additional (perturbing) fields. In spite of this, relatively few studies have experimentally addressed the motion of ions in ion traps. Trajectories can be calculated and plotted through computer simulations for idealized traps, but the accuracy of modeling real traps has yet to be established. The authors have developed a methodology, based on spatially-resolved photodissociation, for the direct measurement of ion densities in the ITMS. Both the ring electrode and/or the end caps can be slotted (>1 mm width) to allow optical access along the trap`s axial or radial axes. Measurement of photodissociation products as a function of position and trap operational parameters then allows spatially resolved determination of the number densities of the parent ions.

  4. Quadrupole magnet for a rapid cycling synchrotron

    SciTech Connect

    Witte, H.; Berg, J. S.

    2015-05-03

    Rapid Cycling Synchrotrons (RCS) feature interleaved warm and cold dipole magnets; the field of the warm magnets is used to modulate the average bending field depending on the particle energy. It has been shown that RCS can be an attractive option for fast acceleration of particles, for example, muons, which decay quickly. In previous studies it was demonstrated that in principle warm dipole magnets can be designed which can provide the required ramp rates, which are equivalent to frequencies of about 1 kHz. To reduce the losses it is beneficial to employ two separate materials for the yoke; it was also shown that by employing an optimized excitation coil geometry the eddy current losses are acceptable. In this paper we show that the same principles can be applied to quadrupole magnets targeting 30 T/m with a repetition rate of 1kHz and good field quality.

  5. Experimental results of the betatron sum resonance

    SciTech Connect

    Wang, Y.; Ball, M.; Brabson, B.

    1993-06-01

    The experimental observations of motion near the betatron sum resonance, {nu}{sub x} + 2{nu}{sub z} = 13, are presented. A fast quadrupole (Panofsky-style ferrite picture-frame magnet with a pulsed power supplier) producing a betatron tune shift of the order of 0.03 at rise time of 1 {mu}s was used. This quadrupole was used to produce betatron tunes which jumped past and then crossed back through a betatron sum resonance line. The beam response as function of initial betatron amplitudes were recorded turn by turn. The correlated growth of the action variables, J{sub x} and J{sub z}, was observed. The phase space plots in the resonance frame reveal the features of particle motion near the nonlinear sum resonance region.

  6. Photon decay of giant resonances

    SciTech Connect

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

    1984-01-01

    Measurements have been made of the photon decay of the giant multipole resonances in /sup 208/Pb. The giant resonances were excited by inelastic scattering of 380 MeV /sup 17/O projectile and the photons were detected in the ORNL Spin Spectrometer. The results show a quadrupole resonance ground state gamma branch of 20% while only less than or equal to 2% of the GQR decay proceeds through the 2.6 MeV, 3/sup -/ state. Nearly one half of the GQR decay through a 3/sup -/ state at 4.974 MeV. Photon decay from the dipole and monopole resonances and high spin resonances (4+,6+) are also observed.

  7. 17O nuclear quadrupole coupling constants of water bound to a metal ion: A gadolinium(III) case study

    NASA Astrophysics Data System (ADS)

    Yazyev, Oleg V.; Helm, Lothar

    2006-08-01

    Rotational correlation times of metal ion aqua complexes can be determined from O17 NMR relaxation rates if the quadrupole coupling constant of the bound water oxygen-17 nucleus is known. The rotational correlation time is an important parameter for the efficiency of Gd3+ complexes as magnetic resonance imaging contrast agents. Using a combination of density functional theory with classical and Car-Parrinello molecular dynamics simulations we performed a computational study of the O17 quadrupole coupling constants in model aqua ions and the [Gd(DOTA)(H2O)]- complex used in clinical diagnostics. For the inner sphere water molecule in the [Gd(DOTA)(H2O)]- complex the determined quadrupole coupling parameter χ√1+η2/3 of 8.7MHz is very similar to that of the liquid water (9.0MHz ). Very close values were also predicted for the the homoleptic aqua ions of Gd3+ and Ca2+. We conclude that the O17 quadrupole coupling parameters of water molecules coordinated to closed shell and lanthanide metal ions are similar to water molecules in the liquid state.

  8. Large scale simulation of mass spectra recorded with a quadrupole ion trap mass spectrometer

    NASA Astrophysics Data System (ADS)

    Julian, Randall K.; Reiser, Hans-Peter; Graham Cooks, R.

    1993-02-01

    This paper reports initial results from a study based on a large scale computer simulation of the ion trap mass spectrometer (ITMS). A large number of ions (104) are given initial positions and velocities with selected random distributions within the ion trap and a trajectory is calculated for each ion using a new supercomputer ion trap mass spectrometer simulation called numerical quadrupole simulation. Ion velocity and position are computed by numerical integration of the Mathieu equations for a quadrupole field superimposed with a pure dipole term to approximate the electric fields present during resonance ejection. The integration is accomplished via a Taylor series approximation of the solution to the equations of motion. The simulation produces mass spectra which are quantitatively compared with experimental data collected from an ITMS. The actual ITMS electrode geometry was measured as well as the r.f. voltage applied to the ring electrode during mass analysis. Based on these measurements the program was generalized to approximate the quadrupole field created by the non-ideal ITMS electrodes. Good agreement in peak shape and the r.f. voltage of ion ejection is achieved for the molecular ion region of the decapeptide substance P when experimental results are compared with simulations. This is true both in the low and high resolution experiments, the latter being achieved by lowering the rate at which the r.f. voltage is scanned. Data are also given showing that resonant ejection of ions is controlled by the phases of the r.f. and a.c. potentials and that resolution can be improved by choosing the a.c. frequency land initial phase angle with respect to the r.f. phase.

  9. Measurement of the electric quadrupole moment of CO.

    PubMed

    Chetty, Naven; Couling, Vincent W

    2011-04-28

    Measurements of the temperature dependence of the Buckingham effect (electric-field-gradient-induced birefringence, EFGIB) for gaseous carbon monoxide are presented. The measurements span the temperature range 301.2-473.9 K, which allows for separation of the temperature-independent hyperpolarizability contribution from the temperature-dependent quadrupole contribution. It is demonstrated that in the case of carbon monoxide, quantization of the rotational motion of the molecules needs to be considered, the analysis yielding a quadrupole moment of ? = (-8.77 0.31) 10(-40) C m(2) and a hyperpolarizability term of b' = (-0.1243 0.0078) 10(-60) C(3) m(4) J(-2). For dipolar molecules, the quadrupole moment is origin dependent, and the value reported here is referred to an origin called the effective quadrupole center. Comparison of this value with the center-of-mass quadrupole moment obtained from other experiments yields information about the dynamic dipole-quadrupole and dipole-magnetic dipole polarizabilities. The temperature-independent term, which contributes (7.0 0.6)% to the EFGIB at room temperature, is by no means insignificant, and must necessarily be accounted for if the quadrupole moment is to be definitively established. The measured ? and b' are compared with the best available ab initio calculated values. PMID:21528960

  10. Measurement of the electric quadrupole moment of N2O.

    PubMed

    Chetty, Naven; Couling, Vincent W

    2011-04-14

    Measurements of the temperature dependence of the Buckingham effect (electric-field-gradient-induced birefringence, EFGIB) for gaseous nitrous oxide are presented. Measurements span the temperature range 298.5-473.9 K, which allows for separation of the temperature-independent hyperpolarizability term from the temperature-dependent quadrupole term, yielding a quadrupole moment of ? = (-11.03 0.41) 10(-40) C m(2), and a hyperpolarizability term of b = (-0.638 0.063) 10(-60) C(3) m(4) J(-2). For dipolar molecules, the quadrupole moment is origin dependent, and the value reported here is referred to an origin called the effective quadrupole center (EQC). Comparison of this value with the center of mass (CM) quadrupole moment obtained from MBER experiments yields information about the dynamic dipole-quadrupole and dipole-magnetic dipole polarizabilities. The temperature-independent term, previously assumed to contribute negligibly to the EFGIB, is found to contribute some (5.2 0.6)% to the effect at room temperature and clearly needs to be accounted for if the quadrupole moment is to be definitively established. PMID:21495755

  11. Prediction of collective characteristics for ion ensembles in quadrupole ion traps without trajectory simulations.

    PubMed

    Goeringer, Douglas E; Viehland, Larry A; Danailov, Daniel M

    2006-07-01

    Fundamental aspects are presented of a two-temperature moment theory for quadrupole ion traps developed via transformation of the Boltzmann equation. Solutions of the moment equations correspond to changes in the ensemble average for any function of ion velocity, because the Boltzmann equation reflects changes to an ion distribution as a whole. The function of primary interest in this paper is the ion effective temperature and its behavior during ion storage and resonance excitation. Calculations suggest that increases in ion effective temperature during resonance excitation are due primarily to power absorption from the main RF trapping field rather than from the dipolar excitation signal. The dipolar excitation signal apparently serves mainly to move ions into regions of the ion trap where the RF electric field, and thus ion RF heating, is greater than near the trap center. Both ideal and non-ideal ion trap configurations are accounted for in the moment equations by incorporating parameterized variables a and q , which are modified versions of the commonly used forms for the DC and AC ring voltages, and b and d , which are new forms that account for the voltages applied to the endcaps. Besides extending the applicability of the moment equations to non-ideal quadrupole ion traps, the modified versions of the parameterized variables can have additional utility. Calculation of the spatial dependence of ion secular oscillation frequencies is demonstrated as an example. PMID:16731002

  12. Suppression of quadrupole polariton generation due to large &(3)circ; effect in Cu2O

    NASA Astrophysics Data System (ADS)

    Mani, Shahin; Jang, Joon; Ketterson, John

    2010-03-01

    Cuprous oxide (Cu2O) is a dipole-forbidden semiconductor exhibiting a vanishing second-order nonlinear susceptibility and a large third-order nonlinear response.^1 We employ resonant two-photon excitation to create quadrupole polaritons in this semiconductor aiming at the Bose-Einstein condensation of polaritons. Generally, to observe this quantum phase transition, high optical excitations at low temperature is essential. Using a Z-scan setup, we explore the resonant two- photon generation of polaritons in Cu2O at 2K. Our results suggest that the third-harmonic generation of the incident light severely limits the polariton density at high excitation levels. Based on the measured nonlinear optical parameters, the experimentally achievable polariton density is estimated. [1] S. Mani, J. I. Jang, and J. B. Ketterson, Opt. Lett. 34, 2817 (2009).

  13. PRINCIPLE OF SKEW QUADRUPOLE MODULATION TO MEASURE BETATRON COUPLING.

    SciTech Connect

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

    2004-07-05

    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.

  14. Synchrotron tune adjustment by longitudinal motion of quadrupoles

    SciTech Connect

    Bertche, K.J.

    1996-07-01

    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.

  15. Beam based alignment of C-shaped quadrupole magnets

    SciTech Connect

    Portmann, G.; Robin, D.

    1998-06-01

    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.

  16. Nuclear spin squeezing via electric quadrupole interaction

    NASA Astrophysics Data System (ADS)

    Aksu Korkmaz, Ya?mur; Bulutay, Ceyhun

    2016-01-01

    Control over nuclear-spin fluctuations is essential for processes that rely on preserving the quantum state of an embedded system. For this purpose, squeezing is a viable alternative, so far that has not been properly exploited for the nuclear spins. Of particular relevance in solids is the electric quadrupole interaction (QI), which operates on nuclei having spin higher than 1/2. In its general form, QI involves an electric-field gradient (EFG) biaxiality term. Here, we show that as this EFG biaxiality increases, it enables continuous tuning of single-particle squeezing from the one-axis twisting to the two-axis countertwisting limits. A detailed analysis of QI squeezing is provided, exhibiting the intricate consequences of EFG biaxiality. The initial states over the Bloch sphere are mapped out to identify those favorable for fast initial squeezing, or for prolonged squeezings. Furthermore, the evolution of squeezing in the presence of a phase-damping channel and an external magnetic field are investigated. We observe that dephasing drives toward an antisqueezed terminal state, the degree of which increases with the spin angular momentum. Finally, QI squeezing in the limiting case of a two-dimensional EFG with a perpendicular magnetic field is discussed, which is of importance for two-dimensional materials, and the associated beat patterns in squeezing are revealed.

  17. Adjustable rare earth quadrupole drift tube magnets

    SciTech Connect

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

    1987-03-01

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

  18. Uv-Uv Hole-Burning Spectroscopy of a Protonated Adenine Dimer in a Cold Quadrupole Ion Trap

    NASA Astrophysics Data System (ADS)

    Kang, Hyuk

    2015-06-01

    A novel method for double-resonance photofragmentation spectroscopy in a cold quadrupole ion trap has been developed and utilized to differentiate the structures of a cold protonated adenine dimer. A burn laser generates a population hole of a certain conformer of the dimer stored in a cold quadrupole ion trap, and an auxiliary dipolar RF ejects the photofragments by the burn laser from the trap. A probe laser detects depletion of a certain conformer by the burn laser, and a conformer-specific UV or IR spectrum of a cold ion is obtained by scanning the wavelength of the burn or the probe laser. This simple and versatile method is applicable to any type of double-resonance photofragmentation spectroscopy in a cold quadrupole ion trap. To demonstrate its capability, it was applied to UV-UV hole-burning spectroscopy of a protonated adenine dimer. It is proved that a cold protonated adenine dimer has at least two hydrogen-bonding geometries and each has multiple electronically excited states with significantly different spectral bandwidths, possibly due to different excited state dynamics.

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

    NASA Astrophysics Data System (ADS)

    Pati, Ranjit

    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 β-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.)

  20. Development of electrostatic quadrupoles for heavy ion fusion

    SciTech Connect

    Faltens, A.; Seidl, P.

    1996-03-01

    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.

  1. Dynamics of a charged drop in a quadrupole electric field

    NASA Astrophysics Data System (ADS)

    Das, Sudip; Mayya, Y. S.; Thaokar, Rochish

    2015-07-01

    Quadrupole electric fields are commonly employed for confining charged conducting drops in Paul traps for studying Rayleigh instability characteristics. We investigate the effect of these fields on the deformation and stability characteristics of a charged liquid drop, using the axisymmetric boundary integral method (BIM). Different combinations of the amount of charge and strength of the electric field give rise to different equilibrium shapes. Interestingly, unlike in the case of uniform fields, stable oblate equilibrium drop shapes are sustained in quadrupole fields. In a positive endcap configuration of the quadrupole setup a drop carrying a small negative charge displays a transition from oblate to prolate as the field strength increases. On the other hand, for the case of a highly charged drop, a shift in the Rayleigh critical charge is observed in the presence of a weak quadrupole field. The Rayleigh instability displays imperfect transcritical bifurcation characteristics with respect to imposed prolate and oblate perturbations. Results are of significance in i) interpreting deformation and the Rayleigh stability effects using Paul traps with quadrupole fields, ii) designing more efficient quadrupole-field-based technologies for emulsification of water in oil.

  2. Designing SSC quadrupole supports to minimize the effects from vibrational noise

    SciTech Connect

    Ritson, D. |

    1993-09-01

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

  3. Towards ferromagnetic quantum criticality in FeGa3 -xGex :71Ga NQR as a zero-field microscopic probe

    NASA Astrophysics Data System (ADS)

    Majumder, M.; Wagner-Reetz, M.; Cardoso-Gil, R.; Gille, P.; Steglich, F.; Grin, Y.; Baenitz, M.

    2016-02-01

    71Ga NQR, magnetization, and specific-heat measurements have been performed on polycrystalline Ge-doped FeGa3 samples. A crossover from an insulator to a correlated local moment metal in the low-doping regime and the evolution of itinerant ferromagnet upon further doping is found. For the nearly critical concentration at the threshold of ferromagnetic order, xC=0.15, 71(1 /T1T ) exhibits a pronounced T-4 /3 power law over two orders of magnitude in temperature, which indicates three-dimensional quantum critical ferromagnetic fluctuations. Furthermore, for the ordered x =0.2 sample (TC≈6 K), 71(1 /T1T ) could be fitted well in the frame of Moriya's self-consistent renormalization theory for weakly ferromagnetic systems with 1 /T1T ˜χ . In contrast to this, the low-doping regime nicely displays local moment behavior where 1 /T1T ˜χ2 is valid. For T →0 , the Sommerfeld ratio γ =(C /T ) is enhanced (70 mJ /mole K2 for x =0.1 ) , which indicates the formation of heavy 3 d electrons.

  4. SPIN COUPLING RESONANCE STUDY IN AGS.

    SciTech Connect

    RANJBAR,V.; AHRENS,L.; BAI,M.; BROWN,K.; GLENN,W.; HUANG,H.; LUCCIO,A.; MACKAY,W.W.; PTITSYN,V.; ROSER,T.; TSOUPAS,N.; LEE,S.Y.

    2002-06-02

    In the AGS spin resonances due to coupling may account for as much as a 50 percent loss in polarization at a reduced acceleration rate. The major source of coupling in the AGS is the solenoidal snake. In the past some preliminary work was done to understand this phenomena, and a method to overcome these resonances was attempted. However in the polarized proton run of 2002 we sought to study more thoroughly the response of these coupled spin resonances to the strength of the solenoidal snake, skew quadrupoles and vertical and horizontal betatron tune separation. In this paper we present our results and compare them with those predicted by a modified DEPOL program.

  5. Theoretical investigation of flute modes in a magnetic quadrupole

    SciTech Connect

    Wu, H.S.

    1988-01-01

    This research developed theories and conducted numerical investigations of electrostatic flute modes in a plasma confined in a magnetic quadrupole. Chapter I presents the discussion of relevant background. Chapter II contains a brief discussion of the basic flute-mode operator L{sub 0} for intermediate- and low-frequency regimes. Chapter III develops a simple theory for a flute mode with frequency between the electron and ion bounce frequencies in the uniform density and temperature regions of a magnetic quadrupole. The frequency is predicted to be inversely proportional to the wave number. Chapter IV describes the kinetic approach. Chapter V contains the derivation of an eigenvalue equation for electrostatic waves with frequencies below the ion frequency in the private flux region of a magnetic quadrupole. Chapter VI develops a theory for electrostatic waves with frequency below the ion bounce frequency in the shared flux region of a magnetic quadrupole. Chapter VII contains the derivation of a dispersion equation for flute modes with frequencies between the electron and ion bounce frequencies in a plasma confined to a magnetic quadrupole. Chapter VIII presents a summary of the research described.

  6. Theoretical investigation of flute modes in a magnetic quadrupole

    SciTech Connect

    Wu, H.S.

    1988-01-01

    The objective of this research is to develop theories and conduct numerical investigations of electrostatic flute modes in a plasma confined in magnetic quadrupole. Chapter I presents the discussion of relevant background. Chapter II contains a brief discussion of the basic flute-mode operator L{sub 0} for intermediate- and low frequency regimes. Chapter III develops a simple theory for a flute mode with frequency between the electron and ion bounce frequencies in the uniform density and temperature regions of a magnetic quadrupole. Chapter IV describes the kinetic approach. Chapter V contains the derivation of an eigenvalue equation for electrostatic waves with frequencies below the ion frequency in the private flux region of a magnetic quadrupole. Chapter VI develops a theory for electrostatic waves with frequency below the ion bounce frequency in the shared flux region of a magnetic quadrupole. Chapter VII contains the derivation of a dispersion equation for flute modes with frequencies between the electron and ion ounce frequencies in a plasma confined to a magnetic quadrupole. Two intermediate-frequency modes are predicted.

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

    NASA Astrophysics Data System (ADS)

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

    2012-09-01

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

  8. Resonances and resonance widths

    SciTech Connect

    Collins, T.

    1986-05-01

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

  9. Excitation of giant resonances via direct reactions

    SciTech Connect

    Bertrand, F.E.

    1982-01-01

    Experimental measurements of electric giant multipole resonances are discussed. The parameters of the giant quadrupole resonance are now firmly established by an extensive set of measurements. The GQR is providing a significant influence in other areas of nuclear physics. The monopole resonance has now been established and its observation has provided the first direct measure of the nuclear compressibility. A strong case for the existence of a giant octupole resonance is now being made through a variety of hadron reactions. However, the supply of giant multipole resonances has not been exhausted. The newer techniques such as higher energy proton scattering, charge exchange reactions, heavy-ion scattering and pion reactions offer considerable hope for identifying new resonances during the next few years.

  10. Cryogen free superconducting splittable quadrupole magnet for linear accelerators

    SciTech Connect

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

    2011-09-01

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

  11. Study of a micro chamber quadrupole mass spectrometer

    SciTech Connect

    Wang Jinchan; Zhang Xiaobing; Mao Fuming; Xiao Mei; Cui Yunkang; Engelsen, Daniel den; Lei Wei

    2008-03-15

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

  12. OPERATIONAL MEASUREMENT OF COUPLING BY SKEW QUADRUPOLE MODULATION.

    SciTech Connect

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

    2004-07-05

    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.

  13. Variable-field permanent magnet quadrupole for the SSC

    SciTech Connect

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

    1993-10-01

    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.

  14. Mechanical Design of a Second Generation LHC IR Quadrupole

    SciTech Connect

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

    2003-11-10

    One of the proposed options to increase the LHC luminosity is the replacement of the existing inner triplets at the Interaction Regions with new low-beta larger aperture quadrupoles operating at the same gradient. Lawrence Berkeley National Laboratory (LBNL) is carrying out preliminary studies of a large-bore Nb{sub 3}Sn quadrupole. The mechanical design presents a support structure based on the use of keys and bladders without self-supporting collars. This technology has been proven effective in several successful common coil Nb{sub 3}Sn dipoles built at LBNL, and it is for the first time applied to a cos(2{var_theta}) design. In this paper we present a detailed analysis of the quadrupole mechanical behavior, demonstrating the possibility of delivering, through this method, well-controlled coil precompression during assembly, cool-down and excitation. The study has been performed with the finite element program ANSYS.

  15. Mechanical design of a large bore quadrupole triplet magnet

    SciTech Connect

    Abbott, S.; Caylor, R.; Fong, E.; Tanabe, J.

    1987-03-01

    The mechanical design and construction of a 1 meter bore, low gradient quadrupole triplet is described. The magnet will be used for focussing a proton beam in accelerator studies of neutral particle at the Los Alamos National Laboratory. A significant feature of this magnet design is the precision location of the coil conductors within the steel yoke tube. Each of the quadrupole coils have been fabricated from water cooled aluminum conductor, wound in a cosine 2-theta geometry. The conductor bundles have been wound to a positional accuracy within +-0.050 cm which was required to reduce the harmonic content to less than 0.04% of the quadrupole field. Important aspects of the design, construction and assembly are described.

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

    SciTech Connect

    Hubbard, S.F.; Petschek, R.G.; Singer, K.D.

    1997-10-01

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

  17. High and ulta-high gradient quadrupole magnets

    SciTech Connect

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

    1985-05-01

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

  18. Axial quadrupole phase of a uniaxial spin-1 magnet

    NASA Astrophysics Data System (ADS)

    Sayko, P. A.; Shapovalov, I. P.

    2015-10-01

    The axial quadrupole phase of uniaxial spin-1 magnet in an external magnetic field has been investigated. The case of magnetic system with the most general form of single-ion anisotropy and anisotropic biquadratic exchange interaction is considered. It is shown that the relative magnetization in the molecular field approximation does not depend on temperature and linearly increases with external magnetic field. Two branches of the spin excitation spectrum are determined. The boundary between the axial quadrupole and angular phases is defined by the condition for softening of the spectrum. The critical temperature of the corresponding phase transition considerably depends on the anisotropy constants of the biquadratic exchange interaction.

  19. Quadrupole Collective Inertia in Nuclear Fission: Cranking Approximation

    SciTech Connect

    Baran, A.; Sheikh, J. A.; Dobaczewski, J.; Nazarewicz, Witold

    2011-01-01

    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 ^{256}Fm. 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.

  20. Conceptual design of a quadrupole magnet for eRHIC

    SciTech Connect

    Witte, H.; Berg, J. S.

    2015-05-03

    eRHIC is a proposed upgrade to the existing Relativistic Heavy Ion Collider (RHIC) hadron facility at Brookhaven National Laboratory, which would allow collisions of up to 21 GeV polarized electrons with a variety of species from the existing RHIC accelerator. eRHIC employs an Energy Recovery Linac (ERL) and an FFAG lattice for the arcs. The arcs require open-midplane quadrupole magnets of up to 30 T/m gradient of good field quality. In this paper we explore initial quadrupole magnet design concepts based on permanent magnetic material which allow to modify the gradient during operation.

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

    PubMed

    Lim, Ae Ran; Kim, In Gyoo

    2015-01-01

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

  2. Reconstruction of nuclear quadrupole interaction in (In,Ga)As/GaAs quantum dots observed by transmission electron microscopy

    NASA Astrophysics Data System (ADS)

    Sokolov, P. S.; Petrov, M. Yu.; Mehrtens, T.; Müller-Caspary, K.; Rosenauer, A.; Reuter, D.; Wieck, A. D.

    2016-01-01

    A microscopic study of the individual annealed (In,Ga)As/GaAs quantum dots is done by means of high-resolution transmission electron microscopy. The Cauchy-Green strain-tensor component distribution and the chemical composition of the (In,Ga)As alloy are extracted from the microscopy images. The image processing allows for the reconstruction of the strain-induced electric-field gradients at the individual atomic columns extracting thereby the magnitude and asymmetry parameter of the nuclear quadrupole interaction. Nuclear magnetic resonance absorption spectra are analyzed for parallel and transverse mutual orientations of the electric-field gradient and a static magnetic field.

  3. Controlling optical properties of metallic multi-shell nanoparticles through suppressed surface plasmon resonance.

    PubMed

    Acapulco, Jesus A I; Hong, Soonchang; Kim, Seong Kyu; Park, Sungho

    2016-01-01

    Herein, we report the surface plasmon resonance of plasmonic multi-shell nanoparticles compared to bimetallic Ag/Au hollow nanospheres of similar final size, shape, and percent composition. The surface plasmon resonance of solid and hollow nanoparticles exhibited a quadrupole mode that was particularly prominent around the 100 nm size regime, while multi-shell nanoparticles did not show a quadrupole mode at a similar size. In the latter case, the quadrupole mode of the outermost nanoshell was suppressed by the dipole modes of the inner shells, and the suppression of the quadrupole mode was not affected by the shape of the inner nanostructures. Light interaction of the multi-shell nanoparticle was investigated through simulated electromagnetic field distribution obtained by finite-difference time domain (FDTD) calculations which were in a good agreement with the results of surface-enhanced Raman spectroscopy (SERS). PMID:26414420

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

    SciTech Connect

    Johnston, D.C.; Borsa, F.; Canfield, P.C.

    1993-10-31

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

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

    ScienceCinema

    Giorgio Ambrosio

    2010-01-08

    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.

  6. Driving a quadrupole mass spectrometer via an isolating stage

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

    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.

  7. Magnetic field data on Fermilab Energy-Saver quadrupoles

    SciTech Connect

    Schmidt, E.E.; Brown, B.C.; Cooper, W.E.; Fisk, H.E.; Gross, D.A.; Hanft, R.; Ohnuma, S.; Turkot, F.T.

    1983-03-01

    The Fermilab Energy Saver/Doubler (Tevatron) accelerator contains 216 superconducting quadrupole magnets. Before installation in the Tevatron ring, these magnets plus an additional number of spares were extensively tested at the Fermilab Magnet Test Facility (MTF). Details on the results of the tests are presented here.

  8. Large energy-spread beam diagnostics through quadrupole scans

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    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.

  9. Ion masking improves resolution in quadrupole mass spectrometers

    NASA Technical Reports Server (NTRS)

    Ierokomos, N.; Ruecker, M. R.

    1973-01-01

    Mass spectrometers analyze molecular composition by determining mass-to-charge ratio of ion fragments of molecules. Study adds significantly to quantitative understanding of quadrupole mass filter. It includes development of quantitative theory of ion oscillations, computer analysis of ion behavior, and identification of determining factors in peak tail size.

  10. Large energy-spread beam diagnostics through quadrupole scans

    SciTech Connect

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

    2012-12-21

    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.

  11. The low-energy quadrupole mode of nuclei

    NASA Astrophysics Data System (ADS)

    Frauendorf, S.

    2015-08-01

    The phenomenological classification of collective quadrupole excitations by means of the Bohr-Hamiltonian (BH) is reviewed with focus on signatures for triaxility. The variants of the microscopic BH derived by means of the Adiabatic Time-Dependent Mean Field theory from the Pairing-plus-quadrupole-quadrupole interaction, the Shell Correction Method, the Skyrme Energy Density Functional, the Relativistic Mean Field Theory and the Gogny interaction are discussed and applications to concrete nuclides reviewed. The Generator Coordinate Method for the five-dimensional quadrupole deformation space and first applications to triaxial nuclei are presented. The phenomenological classification in the framework of the Interacting Boson Model is discussed with a critical view on the boson number counting rule. The recent success in calculating the model parameters by mapping the mean field deformation energy surface on the bosonic one is discussed and the applications listed. A critical assessment of the models is given with focus on the limitations due to the adiabatic approximation. The Tidal Wave approach and the Triaxial Projected Shell Model are presented as practical approaches to calculate spectral properties outside the adiabatic region.

  12. Nuclear quadrupole interaction at99Tc in molybdenum compounds

    NASA Astrophysics Data System (ADS)

    Butz, T.; Lerf, A.; Vogdt, C.; Eid, A. M. M.

    1983-12-01

    The nuclear quadrupole interaction (NQI) at99Tc on molybdenum sites in a series of molybdenum compounds was investigated by time differential perturbed angular correlation. The NQI is rather small for compounds with isolated oxygen/sulfur tetrahedra and fairly large for all compounds with condensed coordination polyhedra.

  13. Targeted Proteomic Quantification on Quadrupole-Orbitrap Mass Spectrometer*

    PubMed Central

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

    2012-01-01

    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

  14. Fermi resonance in dynamical tunneling in a chaotic billiard

    NASA Astrophysics Data System (ADS)

    Yi, Chang-Hwan; Kim, Ji-Hwan; Yu, Hyeon-Hye; Lee, Ji-Won; Kim, Chil-Min

    2015-08-01

    We elucidate that Fermi resonance ever plays a decisive role in dynamical tunneling in a chaotic billiard. Interacting with each other through an avoided crossing, a pair of eigenfunctions are coupled through tunneling channels for dynamical tunneling. In this case, the tunneling channels are an islands chain and its pair unstable periodic orbit, which equals the quantum number difference of the eigenfunctions. This phenomenon of dynamical tunneling is confirmed in a quadrupole billiard in relation with Fermi resonance.

  15. CROSSING A COUPLING SPIN RESONANCE WITH AN RF DIPOLE.

    SciTech Connect

    BAI,M.; ROSER,T.

    2001-06-18

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

  16. Novel methods for detecting buried explosive devices

    NASA Astrophysics Data System (ADS)

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

    1997-07-01

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

  17. Novel methods for detecting buried explosive devices

    SciTech Connect

    Kercel, S.W.; Burlage, R.S.; Patek, D.R.; Smith, C.M.; Hibbs, A.D.; Rayner, T.J.

    1997-04-01

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

  18. Stars as resonant absorbers of gravitational waves

    NASA Astrophysics Data System (ADS)

    McKernan, B.; Ford, K. E. S.; Kocsis, B.; Haiman, Z.

    2014-11-01

    Quadrupole oscillation modes in stars can resonate with incident gravitational waves (GWs), and grow non-linear at the expense of GW energy. Stars near massive black hole binaries (MBHBs) can act as GW-charged batteries, discharging radiatively. Mass-loss from these stars can prompt MBHB accretion at near-Eddington rates. GW opacity is independent of amplitude, so distant resonating stars can eclipse GW sources. Absorption by the Sun of GWs from Galactic white dwarf binaries may be detectable with second-generation space-based GW detectors as a shadow within a complex diffraction pattern.

  19. Giant resonances in /sup 112/Sn

    SciTech Connect

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

    1984-07-01

    The isoscalar giant quadrupole resonance and the giant monopole resonance in /sup 112/Sn were identified at E/sub x/ = 13.3 +- 0.2 MeV and 15.7 +- 0.3 MeV, respectively, using small angle inelastic scattering of 129 MeV alpha particles. The nuclear incompressibility parameters for the volume term (K/sub vol/), the surface term (K/sub surf/), and the symmetry term (K/sub sym/) were determined including /sup 112/Sn.

  20. Resonant transmission of light in chains of high-index dielectric particles

    NASA Astrophysics Data System (ADS)

    Savelev, Roman S.; Filonov, Dmitry S.; Petrov, Mihail I.; Krasnok, Alexander E.; Belov, Pavel A.; Kivshar, Yuri S.

    2015-10-01

    We study numerically, analytically, and experimentally the resonant transmission of light in a waveguide formed by a periodic array of high-index dielectric nanoparticles with a side-coupled resonator. We demonstrate that a resonator with high enough Q -factor provides the conditions for the Fano-type interference allowing one to control the resonant transmission of light. We suggest a practical realization of this resonant effect based on the quadrupole resonance of a dielectric particle and demonstrate it experimentally for ceramic disks at microwave frequencies.

  1. Performance of An Adjustable Strength Permanent Magnet Quadrupole

    SciTech Connect

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

    2006-03-01

    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.

  2. Diabatization based on the dipole and quadrupole: The DQ method

    SciTech Connect

    Hoyer, Chad E.; Xu, Xuefei; Ma, Dongxia; Gagliardi, Laura E-mail: truhlar@umn.edu; Truhlar, Donald G. E-mail: truhlar@umn.edu

    2014-09-21

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

  3. Diabatization based on the dipole and quadrupole: The DQ method

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

  4. Test results of LHC interaction regions quadrupoles produced by Fermilab

    SciTech Connect

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

    2004-10-01

    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.

  5. Quadrupole moments of wobbling excitations in 163Lu

    SciTech Connect

    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

    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.

  6. Permanent-magnet quadrupoles in an RFQ linacs

    SciTech Connect

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

    1985-01-01

    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.

  7. Development and Test of TQC models, LARP Technological Quadrupole Magnets

    SciTech Connect

    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

    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.

  8. ELECTRON TRAPPING IN WIGGLER AND QUADRUPOLE MAGNETS OF CESRTA

    SciTech Connect

    Wang, Lanfa; Huang, Xiaobiao; Pivi, Mauro; /SLAC

    2010-08-25

    The Cornell Electron Storage Ring (CESR) has been reconfigured as an ultra low emittance damping ring for use as a test accelerator (CesrTA) for International Linear Collider (ILC) damping ring R&D [1]. One of the primary goals of the CesrTA program is to investigate the interaction of the electron cloud with low emittance positron beam to explore methods to suppress the electron cloud, develop suitable advanced instrumentation required for these experimental studies and benchmark predictions by simulation codes. This paper reports the simulation of the electron-cloud formation in the wiggler and quadrupole magnets using the 3D code CLOUDLAND. We found that electrons can be trapped with long lifetime in a quadrupole magnet due to the mirror field trapping mechanism and photoelectrons produced in the wiggler zero field zone have long lifetime due to their complicated trajectory.

  9. Improved performance of a quadrupole based glow discharge mass spectrometer

    SciTech Connect

    Valiga, R.E.; Duckworth, D.C.; Smith, D.H.

    1995-12-31

    Glow discharge mass spectrometry (GDMS) has experienced most of its commercial success in trace multi-element analysis using sector-based mass spectrometry. In most cases, the mass resolution available with these instruments allows elements of interest to be analyzed, even in the presence of polyatomic interferences (e.g., ArC+, ArN+, ArO+). Because quadrupole mass filters have little more than unit resolution, background equivalent concentrations (BEC`s) for many elements can be quite high (1-100 ppm). Because of this, many have discounted quadrupole GDMS as a useful trace analysis technique. In this work, the authors have explored methods of reducing the polyatomic interferences.

  10. Ion remeasurement in the RF quadrupole ion trap

    SciTech Connect

    Goeringer, D.E.; McLuckey, S.A.

    1995-12-31

    The development of the mass-selective instability mode of operation for the quadrupole ion trap has provided impetus for mass spectrometric applications of the device. In the technique, the amplitude of the confining rf voltage is increased linearly with time causing trajectories of stored ions to become unstable in the axial direction sequentially from low to high mass/charge. Ejected ions are subsequently detected by an external electron multiplier. Thus, the technique is straightforward but also destructive in nature; any further manipulations of the original ion packet are precluded by ion ejection and subsequent collision with the detector surface. The authors have modified a Teledyne 3DQ quadrupole ion trap mass spectrometer to allow in situ detection and ion remeasurement via image current detection.

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

    PubMed Central

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

    2011-01-01

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

  12. Analysis on linac quadrupole misalignment in FACET commissioning 2012

    SciTech Connect

    Sun, Yipeng; /SLAC

    2012-07-05

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

  13. Magnetic performance of new Fermilab high gradient quadrupoles

    SciTech Connect

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

    1991-05-01

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

  14. Gravitational radiation quadrupole formula is valid for gravitationally interacting systems

    NASA Technical Reports Server (NTRS)

    Walker, M.; Will, C. M.

    1980-01-01

    An argument is presented for the validity of the quadrupole formula for gravitational radiation energy loss in the far field of nearly Newtonian (e.g., binary stellar) systems. This argument differs from earlier ones in that it determines beforehand the formal accuracy of approximation required to describe gravitationally self-interacting systems, uses the corresponding approximate equation of motion explicitly, and evaluates the appropriate asymptotic quantities by matching along the correct space-time light cones.

  15. Electrostatic quadrupole array for focusing parallel beams of charged particles

    DOEpatents

    Brodowski, John

    1982-11-23

    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.

  16. 95Mo magic angle spinning NMR at high field: improved measurements and structural analysis of the quadrupole interaction in monomolybdates and isopolymolybdates.

    PubMed

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

    2005-07-28

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

  17. Statistical thermodynamics of fluids with both dipole and quadrupole moments

    NASA Astrophysics Data System (ADS)

    Benavides, Ana L.; Garca Delgado, Francisco J.; Gmez, Francisco; Lago, Santiago; Garzn, Benito

    2011-06-01

    New Gibbs ensemble simulation data for a polar fluid modeled by a square-well potential plus dipole-dipole, dipole-quadrupole, and quadrupole-quadrupole interactions are presented. This simulation data is used in order to assess the applicability of the multipolar square-well perturbation theory [A. L. Benavides, Y. Guevara, and F. del Ro, Physica A 202, 420 (1994), 10.1016/0378-4371(94)90469-3] to systems where more than one term in the multipole expansion is relevant. It is found that this theory is able to reproduce qualitatively well the vapor-liquid phase diagram for different multipolar moment strengths, corresponding to typical values of real molecules, except in the critical region. Hence, this theory is used to model the behavior of substances with multiple chemical bonds such as carbon monoxide and nitrous oxide and we found that with a suitable choice of the values of the intermolecular parameters, the vapor-liquid equilibrium of these species is adequately estimated.

  18. Transverse beam emittance measurement using quadrupole variation at KIRAMS-430

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

  19. CMB quadrupole suppression. II. The early fast roll stage

    SciTech Connect

    Boyanovsky, D.; Vega, H. J. de; Sanchez, N. G.

    2006-12-15

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

  20. Position Stability Monitoring of THEthe LCLS Undulator Quadrupoles

    SciTech Connect

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

    2012-03-26

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

  1. Nuclear quadrupole interaction in the low dimensional hf-trichalcogenides

    NASA Astrophysics Data System (ADS)

    Saibene, S.; Butz, T.; Lerf, A.; Levy, F.; Abriel, W.

    1990-08-01

    We report on Time Differential Perturbed Angular Correlation measurements of the nuclear quadrupole interaction of181Hf(?-)181 and its temperature dependence in the low dimensional Hf- trichalcogenides HfS3, HfSe3 and HfTe3. In HfS3 the temperature dependence of the precession frequency is a slowly decreasing function with a negative curvature, the deviation from axial symmetry of the electric field gradient is practically temperature independent. In HfSe3 the NQI shows a peculiar behaviour; between 10K and 300K the quadrupole frequency and the asymmetry parameter increase, between 300K and 400K the frequency decreases while the deviation from axial symmetry increases, indicating a structural phase transition near room temperature. In HfTe3 the quadrupole frequency is practically temperature independent below 600K and increases linearely at higher temperatures, the asymmetry parameter increases steadily in the temperature range from 10K to 600K and then decreases. There is a strong correlation between the strength and the asymmetry of the electric field gradient so that the system depends on one control parameter only.

  2. Improved ion optics for introduction of ions into a 9.4-T Fourier transform ion cyclotron resonance mass spectrometer.

    PubMed

    Chen, Yu; Leach, Franklin E; Kaiser, Nathan K; Dang, Xibei; Ibrahim, Yehia M; Norheim, Randolph V; Anderson, Gordon A; Smith, Richard D; Marshall, Alan G

    2015-01-01

    Enhancements to the ion source and transfer optics of our 9.4?T Fourier transform ion cyclotron resonance (ICR) mass spectrometer have resulted in improved ion transmission efficiency for more sensitive mass measurement of complex mixtures at the MS and MS/MS levels. The tube lens/skimmer has been replaced by a dual ion funnel and the following octopole by a quadrupole for reduced ion cloud radial expansion before transmission into a mass-selective quadrupole. The number of ions that reach the ICR cell is increased by an order of magnitude for the funnel/quadrupole relative to the tube lens/skimmer/octopole. PMID:25601704

  3. Excitation and photon decay of giant resonances excited by intermediate energy heavy ions

    SciTech Connect

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

    1987-01-01

    Inelastic scattering of medium energy heavy ions provides very large cross sections and peak-to-continuum ratios for excitation of giant resonances. For energies above about 50 MeV/nucleon, giant resonances are excited primarily through Coulomb excitation, which is indifferent to isospin, thus providing a good probe for the study of isovector giant resonances. The extremely large cross sections available from heavy ion excitation permit the study of rare decay modes of the giant resonances. In particular, recent measurements have been made of the photon decay of giant resonances following excitation by 22 and 84 MeV/nucleon /sup 17/O projectiles. The singles results at 84 MeV/nucleon yield peak cross sections for the isoscalar giant quadrupole resonance and the isovector giant dipole resonance of approximately 0.8 and 3 barns/sr, respectively. Data on the ground state decay of the isoscalar giant quadrupole and isovector giant dipole resonances are presented and compared with calculations. Decays to low-lying excited states are also discussed. Preliminary results from an experiment to isolate the /sup 208/Pb isovector quadrupole resonance using its gamma decay are presented. 22 refs., 19 figs., 1 tab.

  4. (1)H NMR relaxometry and quadrupole relaxation enhancement as a sensitive probe of dynamical properties of solids-[C(NH2)3]3Bi2I9 as an example.

    PubMed

    Florek-Wojciechowska, M; Wojciechowski, M; Jakubas, R; Brym, Sz; Kruk, D

    2016-02-01

    (1)H nuclear magnetic resonance relaxometry has been applied to reveal information on dynamics and structure of Gu3Bi2I9 ([Gu = C(NH2)3] denotes guanidinium cation). The data have been analyzed in terms of a theory of quadrupole relaxation enhancement, which has been extended here by including effects associated with quadrupole ((14)N) spin relaxation caused by a fast fluctuating component of the electric field gradient tensor. Two motional processes have been identified: a slow one occurring on a timescale of about 8 × 10(-6) s which has turned out to be (almost) temperature independent, and a fast process in the range of 10(-9) s. From the (1)H-(14)N relaxation contribution (that shows "quadrupole peaks") the quadrupole parameters, which are a fingerprint of the arrangement of the anionic network, have been determined. It has been demonstrated that the magnitude of the quadrupole coupling considerably changes with temperature and the changes are not caused by phase transitions. At the same time, it has been shown that there is no evidence of abrupt changes in the cationic dynamics and the anionic substructure upon the phase transitions. PMID:26851925

  5. 1H NMR relaxometry and quadrupole relaxation enhancement as a sensitive probe of dynamical properties of solids—[C(NH2)3]3Bi2I9 as an example

    NASA Astrophysics Data System (ADS)

    Florek-Wojciechowska, M.; Wojciechowski, M.; Jakubas, R.; Brym, Sz.; Kruk, D.

    2016-02-01

    1H nuclear magnetic resonance relaxometry has been applied to reveal information on dynamics and structure of Gu3Bi2I9 ([Gu = C(NH2)3] denotes guanidinium cation). The data have been analyzed in terms of a theory of quadrupole relaxation enhancement, which has been extended here by including effects associated with quadrupole (14N) spin relaxation caused by a fast fluctuating component of the electric field gradient tensor. Two motional processes have been identified: a slow one occurring on a timescale of about 8 × 10-6 s which has turned out to be (almost) temperature independent, and a fast process in the range of 10-9 s. From the 1H-14N relaxation contribution (that shows "quadrupole peaks") the quadrupole parameters, which are a fingerprint of the arrangement of the anionic network, have been determined. It has been demonstrated that the magnitude of the quadrupole coupling considerably changes with temperature and the changes are not caused by phase transitions. At the same time, it has been shown that there is no evidence of abrupt changes in the cationic dynamics and the anionic substructure upon the phase transitions.

  6. TESTING OF NB{sub 3}SN QUADRUPOLE COILS USING MAGNETIC MIRROR STRUCTURE

    SciTech Connect

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

    2010-04-09

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

  8. Testing of Nb3Sn quadrupole coils using magnetic mirror structure

    SciTech Connect

    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

    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.

  9. Parametric-Resonance Ionization Cooling in Twin-Helix.

    SciTech Connect

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

    2011-09-01

    Parametric-resonance Ionization Cooling (PIC) is proposed as the final 6D cooling stage of a highluminosity muon collider. For the implementation of PIC, we developed an epicyclic twin-helix channel with correlated optics. Wedge-shaped absorbers immediately followed by short rf cavities are placed into the twin-helix channel. Parametric resonances are induced in both planes using helical quadrupole harmonics. We demonstrate resonant dynamics and cooling with stochastic effects off using GEANT4/G4beamline. We illustrate compensation of spherical aberrations and benchmark COSY Infinity, a powerful tool for aberration analysis and compensation.

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

    SciTech Connect

    Kamiya, Y.; Chao, A.W.

    1983-10-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2008-03-01

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

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

    SciTech Connect

    Albert F. Zeller

    2012-12-28

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

  13. Progress in the development of superconducting quadrupoles for heavy ion fusion

    SciTech Connect

    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

    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.

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

    SciTech Connect

    Friedrich, Jochen; Fu Jinmei; Hendrickson, Christopher L.; Marshall, Alan G.; Wang Yisheng

    2004-11-01

    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.

  15. Finding the Magnetic Center of a Quadrupole to High Resolution

    SciTech Connect

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

    2005-08-12

    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.

  16. Dipole-quadrupole dynamics during magnetic field reversals

    SciTech Connect

    Gissinger, Christophe

    2010-11-15

    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.

  17. Miniature quadrupole mass spectrometer having a cold cathode ionization source

    DOEpatents

    Felter, Thomas E. (Livermore, CA)

    2002-01-01

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

  18. Novel integrated design framework for radio frequency quadrupoles

    NASA Astrophysics Data System (ADS)

    Jolly, Simon; Easton, Matthew; Lawrie, Scott; Letchford, Alan; Pozimski, Jrgen; Savage, Peter

    2014-01-01

    A novel design framework for Radio Frequency Quadrupoles (RFQs), developed as part of the design of the FETS RFQ, is presented. This framework integrates several previously disparate steps in the design of RFQs, including the beam dynamics design, mechanical design, electromagnetic, thermal and mechanical modelling and beam dynamics simulations. Each stage of the design process is described in detail, including the various software options and reasons for the final software suite selected. Results are given for each of these steps, describing how each stage affects the overall design process, with an emphasis on the resulting design choices for the FETS RFQ.

  19. Quadrupole-octupole coupled states in 112Cd

    SciTech Connect

    Garrett, P.E., LLNL

    1998-05-05

    Negative-parity excitations in the 2.5 MeV region in {sup 112}Cd have been investigated with the (n,n`{gamma}) reaction. Several of these states exhibit enhanced B(E2) values for L decay to the 3{sub 1}{sup -} octupole state, indicative of quadrupole-octupole coupled (2{sup +} {circle_times} 3{sup -}) structures. The B(E1) values observed are typically in the range of 1-5 x 1O{sup -4} W u , irrespective of the final state.

  20. Transport properties of a discrete helical electrostatic quadrupole

    SciTech Connect

    Meitzler, C.R.; Antes, K.; Datte, P.; Huson, F.R. ); Xiu, L. . Inst. for Beam Particle Dynamics)

    1991-01-01

    The helical electrostatic quadrupole (HESQ) lens has been proposed as a low energy beam transport system which permits intense H{sup {minus}} beams to be focused into an RFQ without seriously increasing the beam's emittance. A stepwise continuous HESQ lens has been constructed, and preliminary tests have shown that the structure does provide focusing. In order to understand the transport properties of this device, further detailed studies have been performed. Emittances were measured 3.5 cm from the end of the HESQ at two different voltages on the HESQ electrodes. A comparison of these experimental results with a linear model of the HESQ beam transport is made. 4 refs., 5 figs.

  1. Tests of high gradient superconducting quadrupole magnets for the Tevatron

    SciTech Connect

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

    1989-09-01

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

  2. Quench observation using quench antennas on RHIC IR quadrupole magnets

    SciTech Connect

    Ogitsu, T.; Terashima, A.; Tsuchiya, K.; Ganetis, G.; Muratore, J.; Wanderer, P.

    1995-07-01

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

  3. Quench margin measurement in Nb3Sn quadrupole magnet

    SciTech Connect

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

    2008-08-01

    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.

  4. Table of nuclear magnetic dipole and electric quadrupole moments

    SciTech Connect

    Stone, N.J. . E-mail: n.stone1@physics.oxford.ac.uk

    2005-05-01

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

  5. Optimized Superconducting Quadrupole Arrays for Multiple Beam Transport

    SciTech Connect

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

    2005-09-20

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

  6. Small Aperture BPM to Quadrupole Assembly Tolerance Study

    SciTech Connect

    Fong, K. W.

    2010-12-07

    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.

  7. Phase transition study of confined water molecules inside carbon nanotubes: hierarchical multiscale method from molecular dynamics simulation to ab initio calculation.

    PubMed

    Javadian, Soheila; Taghavi, Fariba; Yari, Faramarz; Hashemianzadeh, Seyed Majid

    2012-09-01

    In this study, the mechanism of the temperature-dependent phase transition of confined water inside a (9,9) single-walled carbon nanotube (SWCNT) was studied using the hierarchical multi-scale modeling techniques of molecular dynamics (MD) and density functional theory (DFT). The MD calculations verify the formation of hexagonal ice nanotubes at the phase transition temperature T(c)=275K by a sharp change in the location of the oxygen atoms inside the SWCNT. Natural bond orbital (NBO) analysis provides evidence of considerable intermolecular charge transfer during the phase transition and verifies that the ice nanotube contains two different forms of hydrogen bonding due to confinement. Nuclear quadrupole resonance (NQR) and nuclear magnetic resonance (NMR) analyses were used to demonstrate the fundamental influence of intermolecular hydrogen bonding interactions on the formation and electronic structure of ice nanotubes. In addition, the NQR analysis revealed that the rearrangement of nano-confined water molecules during the phase transition could be detected directly by the orientation of ¹⁷O atom EFG tensor components related to the molecular frame axes. The effects of nanoscale confinements in ice nanotubes and water clusters were analyzed by experimentally observable NMR and NQR parameters. These findings showed a close relationship between the phase behavior and orientation of the electronic structure in nanoscale structures and demonstrate the usefulness of NBO and NQR parameters for detecting phase transition phenomena in nanoscale confining environments. PMID:23085156

  8. Electron-Induced Dissociation of Peptides in a Triple Quadrupole Mass Spectrometer Retrofitted with an Electromagnetostatic Cell

    NASA Astrophysics Data System (ADS)

    Voinov, Valery G.; Bennett, Samuel E.; Barofsky, Douglas F.

    2015-05-01

    Dissociation of peptides induced by interaction with (free) electrons (electron-induced dissociation, EID) at electron energies ranging from near 0 to >30 eV was carried out using a radio-frequency-free electromagnetostatic (EMS) cell retrofitted into a triple quadrupole mass spectrometer. The product-ion mass spectra exhibited EID originating from electronically excited even-electron precursor ions, reduced radical cations formed by capture of low-energy electrons, and oxidized radical cations produced by interaction with high-energy electrons. The spectra demonstrate, within the limits of the triple quadrupole's resolving power, that high-energy EID product-ion spectra produced with an EMS cell exhibit essentially the same qualitative structural information, i.e., amino acid side-chain (SC) losses and backbone cleavages, as observed in high-energy EID spectra produced with a Fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometer. The levels of fragmentation efficiency evident in the product-ion spectra recorded in this study, as was the case for those recorded in earlier studies with FT ICR mass spectrometers, is currently at the margin of analytical utility. Given that this shortcoming can be remedied, EMS cells incorporated into QqQ or QqTOF mass spectrometers could make tandem high-energy EID mass spectrometry more widely accessible for analysis of peptides, small singly charged molecules, pharmaceuticals, and clinical samples.

  9. Electron-induced dissociation of peptides in a triple quadrupole mass spectrometer retrofitted with an electromagnetostatic cell.

    PubMed

    Voinov, Valery G; Bennett, Samuel E; Barofsky, Douglas F

    2015-05-01

    Dissociation of peptides induced by interaction with (free) electrons (electron-induced dissociation, EID) at electron energies ranging from near 0 to >30 eV was carried out using a radio-frequency-free electromagnetostatic (EMS) cell retrofitted into a triple quadrupole mass spectrometer. The product-ion mass spectra exhibited EID originating from electronically excited even-electron precursor ions, reduced radical cations formed by capture of low-energy electrons, and oxidized radical cations produced by interaction with high-energy electrons. The spectra demonstrate, within the limits of the triple quadrupole's resolving power, that high-energy EID product-ion spectra produced with an EMS cell exhibit essentially the same qualitative structural information, i.e., amino acid side-chain (SC) losses and backbone cleavages, as observed in high-energy EID spectra produced with a Fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometer. The levels of fragmentation efficiency evident in the product-ion spectra recorded in this study, as was the case for those recorded in earlier studies with FT ICR mass spectrometers, is currently at the margin of analytical utility. Given that this shortcoming can be remedied, EMS cells incorporated into QqQ or QqTOF mass spectrometers could make tandem high-energy EID mass spectrometry more widely accessible for analysis of peptides, small singly charged molecules, pharmaceuticals, and clinical samples. PMID:25652934

  10. Heavy ion excitation of giant resonances: The next generation

    SciTech Connect

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

    1987-01-01

    The prospects for high energy heavy ion excitation of giant resonances are discussed. A brief review is provided of the results obtained to date using low/medium energy heavy ions and it is suggested that those results show no substantial advantage of heavy ions for giant resonance excitation. Calculations are presented that show that Coulomb excitation becomes the dominant excitation mechanism of the giant resonances for heavy ions above about 100 MeV/nucleon. The Coulomb excitation provides extremely large differential cross sections for excitation of both isovector and isoscalar resonances. Recent data are presented for inelastic scattering of 84 MeV/nucleon /sup 17/O ions on /sup 208/Pb that demonstrate the effectiveness of Coulomb excitation in providing extremely large cross sections and peak-to-continuum ratios for the isoscalar giant quadrupole resonance and the isovector giant dipole resonance. 19 refs., 17 figs.

  11. Fission decay of the isoscalar giant quadrupole resonance in 24Mg

    NASA Astrophysics Data System (ADS)

    Lawitzki, S.; Pade, D.; Gonsior, B.; Uhlhorn, C. D.; Brandenburg, S.; Harakeh, M. N.; Wilschut, H. W.

    1986-07-01

    The 24Mg(?, ??) 12C+ 12C reaction was studied by measuring 12C fragments in coincidence with inelastically scattered ?-particles at E? = 120 MeV. Both 12C fragments were identified using the ?E - E technique. The measured angular correlations indicate that the 12C gs+ 12C gs decay channel is dominated by decay of L = 2 strength, which yields an integrated fraction of 0.14% of the E2 EWSR strength in comparison with 22.2% of the E2 EWSR strength observed in singles inelastic ?-scattering experiments in the same excitation energy region.

  12. High Sensitivity Nuclear Quadrupole Resonance Approach for Detection of Modulation Wave Motion in Incommensurate Systems

    NASA Astrophysics Data System (ADS)

    Ailion, David C.; Norcross, James A.

    1995-03-01

    In contrast to conventional NMR techniques that use magnetic field gradients(MFG's) to detect the diffusion of moving atoms, we have developed a highlysensitive approach for detecting electric field gradient (EFG) fluctuationsseen by stationary atoms. These EFG fluctuations were observed in the quadrupoleperturbed NMR behavior of a stationary nucleus (93Nb)in the incommensurate insulator barium sodium niobate and are attributed tomotion of the modulation wave. We observed effective diffusion constants oforder 10-13 cm2/s, which are 4 orders of magnitude smaller than those currently detectable with MFG NMR.

  13. High Reliability Prototype Quadrupole for the Next Linear Collider

    NASA Astrophysics Data System (ADS)

    Spencer, C. M.

    2001-01-01

    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.

  14. Nuclear electric quadrupole moment of potassium from the molecular method

    NASA Astrophysics Data System (ADS)

    Teodoro, Tiago Quevedo; Haiduke, Roberto Luiz Andrade; Visscher, Lucas

    2015-03-01

    The current standard nuclear quadrupole moments (NQMs) of the 39K , 40K , and 41K isotopes have recently been contested by Singh and co-workers on the basis of their atomic computational data [Singh et al., Phys. Rev. A 86, 032509 (2012), 10.1103/PhysRevA.86.032509]. Thus we performed relativistic calculations of electric field gradients at the potassium nuclei in three diatomic molecules (KF, KCl, and KBr) and combined these values with accurate experimental nuclear quadrupole coupling constants to provide an independent assessment of these NQMs. Our most accurate results, obtained by treating electron correlation with coupled cluster theory, employing a four-component Hamiltonian that includes the Gaunt two-electron correction, and with an incremented relativistic basis set of quadruple-? quality, yield Q (39K)=60.3 (6 ) , Q (40K)=-75.0 (8 ) , and Q (41K)=73.4 (7 ) mb . These values are in better agreement with the results obtained by Singh et al. and indicate that the standard NQMs should be revised.

  15. Density enhancement of an RF plasma in a magnetic quadrupole

    NASA Astrophysics Data System (ADS)

    Teske, Christian; Iberler, Marcus; Jacoby, Joachim

    2008-05-01

    A new method for the effective confinement of a low pressure gas discharge has been proposed by Christiansen and Jacoby. The principal component is a magnetic quadrupole superimposed upon an RF-driven gas discharge plasma. It has been suggested to use the device as an ion source for accelerator applications and as a plasma target to investigate the interaction of heavy ion beams with a magnetically confined plasma. A complete experiment including a capacitively coupled radio frequency (CCRF) discharge and an electric quadrupole magnet was set up and investigated by applying spectroscopic diagnostic methods. The plasma parameters for the magnetically confined CCRF discharge were measured using a Ar : He gas mixture. The electron temperature and the electron density as a function of the gas pressure and the magnetic field could be determined. A maximum of the mean electron temperature was identified as due to collisionless heating. Further, an ion beam was extracted and the mean electron density derived. The confinement of the plasma at low pressures between 0.4 and 1 Pa has also been obtained with an electron density of 3 1017 m-3.

  16. Adjustable permanent quadrupoles for the next linear collider

    SciTech Connect

    James T. Volk et al.

    2001-06-22

    The proposed Next Linear Collider (NLC) will require over 1400 adjustable quadrupoles between the main linacs' accelerator structures. These 12.7 mm bore quadrupoles will have a range of integrated strength from 0.6 to 138 Tesla, with a maximum gradient of 141 Tesla per meter, an adjustment range of +0 to {minus}20% and effective lengths from 324 mm to 972 mm. The magnetic center must remain stable to within 1 micron during the 20% adjustment. In an effort to reduce costs and increase reliability, several designs using hybrid permanent magnets have been developed. Four different prototypes have been built. All magnets have iron poles and use Samarium Cobalt to provide the magnetic fields. Two use rotating permanent magnetic material to vary the gradient, one uses a sliding shunt to vary the gradient and the fourth uses counter rotating magnets. Preliminary data on gradient strength, temperature stability, and magnetic center position stability are presented. These data are compared to an equivalent electromagnetic prototype.

  17. Extracting the Omega- electric quadrupole moment from lattice QCD data

    SciTech Connect

    G. Ramalho, M.T. Pena

    2011-03-01

    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].

  18. Precision Magnet Measurements for X-Band Accelerator Quadrupole Triplets

    SciTech Connect

    Marsh, R A; Anderson, S G; Armstrong, J P

    2012-05-16

    An X-band test station is being developed at LLNL to investigate accelerator optimization for future upgrades to mono-energetic gamma-ray (MEGa-Ray) technology at LLNL. Beamline magnets will include an emittance compensation solenoid, windowpane steering dipoles, and quadrupole magnets. Demanding tolerances have been placed on the alignment of these magnets, which directly affects the electron bunch beam quality. A magnet mapping system has been established at LLNL in order to ensure the delivered magnets match their field specification, and the mountings are aligned and capable of reaching the specified alignment tolerances. The magnet measurement system will be described which uses a 3-axis Lakeshore gauss probe mounted on a 3-axis translation stage. Alignment accuracy and precision will be discussed, as well as centering measurements and analysis. The dependence on data analysis over direct multi-pole measurement allows a significant improvement in useful alignment information. Detailed analysis of measurements on the beamline quadrupoles will be discussed, including multi-pole content both from alignment of the magnets, and the intrinsic level of multi-pole magnetic field.

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

    NASA Astrophysics Data System (ADS)

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

    2011-09-01

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

  20. Adaptation of a 3-D quadrupole ion trap for dipolar DC collisional activation.

    PubMed

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

    2011-09-01

    Means to allow for the application of a dipolar DC pulse to the end-cap electrodes of a three-dimensional (3-D) quadrupole ion trap for as short as a millisecond to as long as hundreds of milliseconds are described. The implementation of dipolar DC does not compromise the ability to apply AC waveforms to the end-cap electrodes at other times in the experiment. Dipolar DC provides a nonresonant means for ion acceleration by displacing ions from the center of the ion trap where they experience stronger rf electric fields, which increases the extent of micro-motion. The evolution of the product ion spectrum to higher generation products with time, as shown using protonated leucine enkephalin as a model protonated peptide, illustrates the broad-band nature of the activation. Dipolar DC activation is also shown to be effective as an ion heating approach in mimicking high amplitude short time excitation (HASTE)/pulsed Q dissociation (PQD) resonance excitation experiments that are intended to enhance the likelihood for observing low m/z products in ion trap tandem mass spectrometry. PMID:21953251

  1. High-resolution laser spectroscopy of ultracold ytterbium atoms using spin-forbidden electric quadrupole transition

    NASA Astrophysics Data System (ADS)

    Uetake, S.; Yamaguchi, A.; Hashimoto, D.; Takahashi, Y.

    2008-11-01

    We have successfully observed high-resolution spectra of spin-forbidden electric quadrupole transition (1 S 0?3 D 2) in ytterbium (174Yb) atoms. The differential light shifts between the 1 S 0 and the 3 D 2 states in a far-off resonant trap at 532 nm are also measured. For the spectroscopy, we developed simple, narrow-linewidth, and long-term frequency stabilized violet diode laser systems. Long-term drifts of the excitation laser (404 nm) is suppressed by locking the laser to a length stabilized optical cavity. The optical path length of the cavity is stabilized to another diode laser whose frequency is locked to a strong 1 S 0?1 P 1 transition (399 nm) of Yb. Both lasers are standard extended-cavity diode lasers (ECDLs) in the Littrow configuration. Since the linewidth of a violet ECDL (10 MHz) is broader than a typical value of a red or near infra-red ECDL (<1 MHz), we employ optical feedback from a narrow-band Fabry-Perot cavity to reduce the linewidth. The linewidth is expected to be <20 kHz for 1 ms averaging time, and the long-term frequency stability is estimated to be 200 kHz/h.

  2. Fano resonance properties of gold nanocrescent arrays.

    PubMed

    Liao, Zhongwei; Zhou, Bingpu; Huang, Yingzhou; Li, Shunbo; Wang, Shuxia; Wen, Weijia

    2014-10-01

    The Fano resonance induced by symmetry breaking could improve the sensitivity of localized surface plasmon resonance sensors. In this work, the spectra of gold nanocrescent arrays are measured and confirmed by simulation results through the finite element method (FEM). The Fano resonance presented in the spectra could be modulated by the symmetry breaking with different waist widths, which are understood through plasmonic hybridization theory with the help of surface charge distribution. Our results indicate the Fano lineshape is generated by the coherent coupling of the quadrupole plasmon mode QH of nanohole and the antibonding plasmon mode D(AB) of nanocrescent. Finally, the high figure of merit (FoM=1.6-3.5) of the Q mode in the visible region illustrates this nanocrescent Fano sensor is of great value in the biological and chemical scientific fields. PMID:25322229

  3. Solution-State (17) O?Quadrupole Central-Transition NMR Spectroscopy in the Active Site of Tryptophan Synthase.

    PubMed

    Young, Robert P; Caulkins, Bethany G; Borchardt, Dan; Bulloch, Daryl N; Larive, Cynthia K; Dunn, Michael F; Mueller, Leonard J

    2016-01-01

    Oxygen is an essential participant in the acid-base chemistry that takes place within many enzyme active sites, yet has remained virtually silent as a probe in NMR spectroscopy. Here, we demonstrate the first use of solution-state (17) O?quadrupole central-transition NMR spectroscopy to characterize enzymatic intermediates under conditions of active catalysis. In the 143?kDa pyridoxal-5'-phosphate-dependent enzyme tryptophan synthase, reactions of the ?-aminoacrylate intermediate with the nucleophiles indoline and 2-aminophenol correlate with an upfield shift of the substrate carboxylate oxygen resonances. First principles calculations suggest that the increased shieldings for these quinonoid intermediates result from the net increase in the charge density of the substrate-cofactor ?-bonding network, particularly at the adjacent ?-carbon site. PMID:26661504

  4. Quantitative analysis of sphingolipids for lipidomics using triple quadrupole and quadrupole linear ion trap mass spectrometers[S

    PubMed Central

    Shaner, Rebecca L.; Allegood, Jeremy C.; Park, Hyejung; Wang, Elaine; Kelly, Samuel; Haynes, Christopher A.; Sullards, M. Cameron; Merrill, Alfred H.

    2009-01-01

    Sphingolipids are a highly diverse category of bioactive compounds. This article describes methods that have been validated for the extraction, liquid chromatographic (LC) separation, identification and quantitation of sphingolipids by electrospray ionization, tandem mass spectrometry (ESI-MS/MS) using triple quadrupole (QQQ, API 3000) and quadrupole-linear-ion trap (API 4000 QTrap, operating in QQQ mode) mass spectrometers. Advantages of the QTrap included: greater sensitivity, similar ionization efficiencies for sphingolipids with ceramide versus dihydroceramide backbones, and the ability to identify the ceramide backbone of sphingomyelins using a pseudo-MS3 protocol. Compounds that can be readily quantified using an internal standard cocktail developed by the LIPID MAPS Consortium are: sphingoid bases and sphingoid base 1-phosphates, more complex species such as ceramides, ceramide 1-phosphates, sphingomyelins, mono- and di-hexosylceramides, and these complex sphingolipids with dihydroceramide backbones. With minor modifications, glucosylceramides and galactosylceramides can be distinguished, and more complex species such as sulfatides can also be quantified, when the internal standards are available. JLR LC ESI-MS/MS can be utilized to quantify a large number of structural and signaling sphingolipids using commercially available internal standards. The application of these methods is illustrated with RAW264.7 cells, a mouse macrophage cell line. These methods should be useful for a wide range of focused (sphingo)lipidomic investigations. PMID:19036716

  5. Measuring the Magnetic Center Behavior of an ILC Superconducting Quadrupole Prototype

    SciTech Connect

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

    2011-02-07

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

  6. The quadrupole coupling constant of HNC. [hydrogen isocyanide hyperfine structure measurements

    NASA Technical Reports Server (NTRS)

    Snyder, L. E.; Hollis, J. M.; Buhl, D.

    1977-01-01

    The letter reports resolved measurements of the quadrupole hyperfine structure of HNC (hydrogen isocyanide). These measurements were made in the direction of the cool interstellar dust cloud L134, and were used to make an experimental determination of a fundamental spectroscopic constant of HNC, its quadrupole coupling constant.

  7. Investigation of the nuclear quadrupole interaction in the single crystals by ?-? induced angular correlation

    NASA Astrophysics Data System (ADS)

    Denisenko, G. A.

    A theory of the ?-? induced angular correlation (IAC) is given, The possibilities of using such a correlation to investigate the nuclear quadrupole interaction (NQI) in solids to obtain information about the components of the dynamic quadrupole coupling tensor and the crystal structure defects are considered. The ?-? IAC is used to determine simultaneously the magnitude and the sign of the NQI.

  8. Magnetic resonance cell

    SciTech Connect

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

    1984-05-01

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

  9. A superconducting quadrupole magnet array for a heavy ion fusion driver

    SciTech Connect

    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

    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.

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

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

    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.

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

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

    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.

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

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

    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.

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

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

    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.

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

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

    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.

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

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

    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.

  16. Determination of nuclear quadrupole moments An example of the synergy of ab initio calculations and microwave spectroscopy

    SciTech Connect

    Kell, Vladimir

    2015-01-22

    Highly correlated scalar relativistic calculations of electric field gradients at nuclei in diatomic molecules in combination with accurate nuclear quadrupole coupling constants obtained from microwave spectroscopy are used for determination of nuclear quadrupole moments.

  17. Auxiliary Frequency Parametric Excitation of Quadrupole Mass Spectrometers

    NASA Technical Reports Server (NTRS)

    Gershman, Daniel (Inventor); Block, Bruce (Inventor); Rubin, Martin (Inventor); Zurbuchen, Thomas (Inventor)

    2013-01-01

    The apparatus introduces a second adjustable resonant point in a QMS at a frequency that is close to a multiple of the fundamental frequency by adjusting driving point impedance characteristics of the QMS. The apparatus measures the first and second resonant point of the QMS to account for changes in the operational characteristics of the QMS.

  18. Optical resonator

    NASA Technical Reports Server (NTRS)

    Taghavi-Larigani, Shervin (Inventor); Vanzyl, Jakob J. (Inventor); Yariv, Amnon (Inventor)

    2006-01-01

    The invention discloses a semi-ring Fabry-Perot (SRFP) optical resonator structure comprising a medium including an edge forming a reflective facet and a waveguide within the medium, the waveguide having opposing ends formed by the reflective facet. The performance of the SRFP resonator can be further enhanced by including a Mach-Zehnder interferometer in the waveguide on one side of the gain medium. The optical resonator can be employed in a variety of optical devices. Laser structures using at least one SRFP resonator are disclosed where the resonators are disposed on opposite sides of a gain medium. Other laser structures employing one or more resonators on one side of a gain region are also disclosed.

  19. Covariant spectator theory of np scattering: Deuteron quadrupole moment

    SciTech Connect

    Gross, Franz

    2015-01-26

    The deuteron quadrupole moment is calculated using two CST model wave functions obtained from the 2007 high precision fits to np scattering data. Included in the calculation are a new class of isoscalar np interaction currents automatically generated by the nuclear force model used in these fits. The prediction for model WJC-1, with larger relativistic P-state components, is 2.5% smaller that the experiential result, in common with the inability of models prior to 2014 to predict this important quantity. However, model WJC-2, with very small P-state components, gives agreement to better than 1%, similar to the results obtained recently from XEFT predictions to order N3LO.

  20. Covariant spectator theory of np scattering: Deuteron quadrupole moment

    DOE PAGESBeta

    Gross, Franz

    2015-01-26

    The deuteron quadrupole moment is calculated using two CST model wave functions obtained from the 2007 high precision fits to np scattering data. Included in the calculation are a new class of isoscalar np interaction currents automatically generated by the nuclear force model used in these fits. The prediction for model WJC-1, with larger relativistic P-state components, is 2.5% smaller that the experiential result, in common with the inability of models prior to 2014 to predict this important quantity. However, model WJC-2, with very small P-state components, gives agreement to better than 1%, similar to the results obtained recently frommore »XEFT predictions to order N3LO.« less

  1. New table of recommended nuclear electric quadrupole moments

    NASA Astrophysics Data System (ADS)

    Stone, N. J.

    2015-04-01

    A new Table of Recommended Nuclear Electric Quadrupole Moments has been prepared and published by the Nuclear Data Section of the IAEA, Vienna Stone (2013). The main feature of the new Table is the adoption, wherever possible, of the best available calculation of the electric field gradient (efg), required to extract the moment from the measured quantity in most measurement methods. All original results have been normalized to take account of differences between the efg used in the original publication and the adopted value. The aim of the new table is to provide a standard reference in which the value given for each moment is the best available and for which full provenance is given.

  2. Triaxial dynamics in the quadrupole-deformed rotor

    NASA Astrophysics Data System (ADS)

    Qiu-Yue, Li; Xiao-Xiang, Wang; Yan, Zuo; Yu, Zhang; Feng, Pan

    2016-01-01

    The triaxial dynamics of the quadrupole-deformed rotor model of both the rigid and the irrotational type are investigated in detail. The results indicate that level patterns of the two types of model can be matched with each other to the leading order of the deformation parameter ?. In particular, it is found that the dynamical structure of the irrotational type with most triaxial deformation (? = 30) is equivalent to that of the rigid type with oblate deformation (? = 60), and the associated spectrum can be classified into the standard rotational bands obeying the rotational L(L+1)-law or regrouped into a new ground- and ?-band with oddeven staggering in the new ?-band, commonly recognized as a signature of the triaxiality. The differences between the two types of the model in this case are emphasized, especially in the E2 transitional characteristics. Supported by National Natural Science Foundation of China (11375005, 11005056, 11175078)

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

    SciTech Connect

    Jentschura, U. D.; Milstein, A. I.; Terekhov, I. S.; Boie, H.; Scheit, H.; Schwalm, D.

    2008-01-15

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

  4. Massive higher spin states in string theory and gravitational quadrupoles

    SciTech Connect

    Giannakis, I.; Liu, J.T.; Porrati, M.

    1999-05-01

    In this paper we study three point functions of the type II superstring involving one graviton and two massive states, focusing in particular on the spin- (7) /(2) fermions at the first mass level. Defining a gravitational quadrupole {open_quotes}{ital h} factor,{close_quotes} we find that the nonminimal interactions of string states in general are parametrized by h{ne}1, in contrast with the preferred field theory value of h=1 (for tree-level unitarity). This difference arises from the fact that consistent gravitational interactions of strings are related to the presence of a complete tower of massive states, not present in the ordinary field theory case. {copyright} {ital 1999} {ital The American Physical Society}

  5. Plasma-beam traps and radiofrequency quadrupole beam coolers

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

    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.

  6. A Cryogenic test stand for LHC quadrupole magnets

    SciTech Connect

    R. J. Rabehl et al.

    2004-03-09

    A new test stand for testing LHC interaction region (IR) quadrupole magnets at the Fermilab Magnet Test Facility has been designed and operated. The test stand uses a double bath system with a lambda plate to provide the magnet with a stagnant bath of pressurized He II at 1.9 K and 0.13 MPa. A cryostated magnet 0.91 m in diameter and up to 13 m in length can be accommodated. This paper describes the system design and operation. Issues related to both 4.5 K and 1.9 K operations and magnet quenching are highlighted. An overview of the data acquisition and cryogenics controls systems is also included.

  7. Manufacturing experience for the LHC inner triplet quadrupole cables

    SciTech Connect

    Scanlan, R.M.; Higley, H.C.; Bossert, R.; Kerby, J.; Gosh, A.K.; Boivin, M.; Roy, T.

    2001-06-12

    The design for the U.S. LHC Inner Triplet Quadrupole magnet requires a 37 strand (inner layer) and a 46 strand (outer layer) cable. This represents the largest number of strands attempted to date for a production quantity of Rutherford-type cable. The cable parameters were optimized during the production of a series of short prototype magnets produced at FNAL. These optimization studies focused on critical current degradation, dimensional control, coil winding, and interstrand resistance. After the R&D phase was complete, the technology was transferred to NEEW and a new cabling machine was installed to produce these cables. At present, about 60 unit lengths, out of 90 required for the entire production series of magnets, have been completed for each type of cable. The manufacturing experience with these challenging cables will be reported. Finally, the implications for even larger cables, with more strands, will be discussed.

  8. Nb3Sn Quadrupole Magnets for the LHC IR

    SciTech Connect

    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

    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.

  9. Plasma-beam traps and radiofrequency quadrupole beam coolers

    SciTech Connect

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

    2014-02-15

    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.

  10. Design and fabrication of the BNL radio frequency quadrupole

    SciTech Connect

    McKenzie-Wilson, R.B.

    1983-01-01

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

  11. Investigation of a quadrupole ultra-high vacuum ion pump

    NASA Technical Reports Server (NTRS)

    Schwarz, H. J.

    1974-01-01

    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.

  12. Dynamical Quadrupole Interactions in the Hafnium Deuterium System

    NASA Astrophysics Data System (ADS)

    Forker, M.; Freise, L.; Simon, D.; Saitovitch, H.; Silva, P. R. J.

    1986-02-01

    The nuclear quadrupole interaction (NQI) at the site of 181Ta in HfD2 has been investigated by time differential perturbed angular correlation measurements. Below 290 K the NQI is static within a 300 nanosecond time window. Above 290 K dynamic effects related to the diffusion of deuterium atoms start to appear, which have been analyzed in terms of a 3-state stochastic model. Between 345 K and 500 K the jump diffusion of deuterium has an activation energy Ea = (0 .3 3-0.4+0.9 ) eV. At higher temperatures the relaxation spectra suggest that transitions occur, first to the ?-phase, then to the ?-phase of the hafnium-deuterium system. At 600 K the mean residence time between jumps is of the order of 2 nanoseconds. First measurements with HfH2 show an isotope effect compatible with the prediction of the classical rate theory for over-barrier diffusion.

  13. Nuclear quadrupole interaction of199mHg-ferrocenethiol complexes

    NASA Astrophysics Data System (ADS)

    Butz, T.; Trger, W.; Phlmann, Th.; Nuyken, O.

    1993-03-01

    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.

  14. Resonance scraping

    SciTech Connect

    Collins, T.

    1986-06-01

    Protons lost in a ring leave at a few preferred locations, determined by some non-linear property of the dipoles. This paper suggests taking control of lost protons by beating the magnets at their own game - by means of a designed resonance used as a beam scraper. It is a study of suitable resonances, including estimates of the required multipole element strengths. The appropriate resonances are two-dimensional. A large number of figures is included.

  15. Resonance ionization spectroscopy in atmospheric plasmas with mass spectrometric detection for trace analysis

    SciTech Connect

    Turk, Gregory C.; Yu, Lijian; Koirtyohann, S. Roy

    1995-04-01

    Ions created through resonance ionization spectroscopy or laser-enhanced ionization in both an inductively coupled plasma and an air-hydrogen flame have been differentially pumped into a vacuum and detected by quadrupole mass spectrometry. This new variety of resonance ionization mass spectrometry combines the high selectivity of an optical/mass spectrometric technique with the ease of sample introduction of atmospheric plasma atomization.

  16. Stochastic resonance

    NASA Astrophysics Data System (ADS)

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

    1998-01-01

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

  17. Low-temperature nuclear magnetic resonance investigation of systems frustrated by competing exchange interactions

    NASA Astrophysics Data System (ADS)

    Roy, Beas

    This doctoral thesis emphasizes on the study of frustrated systems which form a very interesting class of compounds in physics. The technique used for the investigation of the magnetic properties of the frustrated materials is Nuclear Magnetic Resonance (NMR). NMR is a very novel tool for the microscopic study of the spin systems. NMR enables us to investigate the local magnetic properties of any system exclusively. The NMR experiments on the different systems yield us knowledge of the static as well as the dynamic behavior of the electronic spins. Frustrated systems bear great possibilities of revelation of new physics through the new ground states they exhibit. The vandates AA'VO(PO4)2 [AA' ? Zn2 and BaCd] are great prototypes of the J1-J2 model which consists of magnetic ions sitting on the corners of a square lattice. Frustration is caused by the competing nearest-neighbor (NN) and next-nearest neighbor (NNN) exchange interactions. The NMR investigation concludes a columnar antiferromagnetic (AFM) state for both the compounds from the sharp peak of the nuclear spin-lattice relaxation rate (1/T1) and a sudden broadening of the 31P-NMR spectrum. The important conclusion from our study is the establishment of the first H-P-T phase diagram of BaCdVO(PO4)2. Application of high pressure reduces the saturation field (HS) in BaCdVO(PO4)2 and decreases the ratio J2/J1, pushing the system more towards a questionable boundary (a disordered ground state) between the columnar AFM and a ferromagnetic ground state. A pressure up to 2.4 GPa will completely suppress HS. The Fe ions in the `122' iron-arsenide superconductors also sit on a square lattice thus closely resembling the J1-J2 model. The 75As-NMR and Nuclear Quadrupole Resonance (NQR) experiments are conducted in the compound CaFe2As2 prepared by two different heat treatment methods (`as-grown' and `annealed'). Interestingly the two samples show two different ground states. While the ground state of the `as-grown' sample shows a non-magnetic collapsed tetragonal phase (with no magnetic fluctuations), the ground state of the `annealed' sample shows a magnetically long-range ordered orthorhombic phase. The temperature dependence of 1/T1 and that of Knight shift showed that the electron correlations completely disappear in the nonsuperconducting collapsed tetragonal phase in `as-grown' sample of CaFe2As2 indicating quenching of Fe moments. The insulating A-site spinel compound CoAl2O4 exhibits frustration due to competing NN and NNN exchange interactions. This compound has been studied for a long time yet there has been a contradiction as to what the ground state of this compound is. The origin of this ambiguity was pointed out to be microstructure effects such as site-inversion between Co and Al. Thus depending on the value of degree of site inversion x [(Co{1-x}Alx)[Al{2-x}Cox]O4], the ground states differ. A very high quality sample was prepared (x ? 0.06) and 27Al and 59Co NMR were performed to study the ground state of this compound. Together with the results from heat capacity, magnetic measurements and neutron diffraction measurements we conclude that the ground state is collinear AFM. We settled a long debated problem for the ground state of CoAl2O4. The compound BiMn2PO6 is a magnetically frustrated system with three-dimensional magnetic ordering. Frustration in this compound is caused by the comparable values of the exchange interactions along the chain, along the rung and in between the ladders. Thus the magnetic structure of this compound is quite complex with the temperature dependence of magnetic susceptibility exhibiting peak at 30 K, a jump at 43 K and a change of slope at 10 K. 31P-NMR study was done on this system to investigate the nature of transitions (if any) at these temperatures. NMR study suggested a long-range AFM transition at 30 K with a sharp peak in 1/T1. No signature of transition at 43 K suggested its origin is extrinsic. Between 10 K and 30 K the NMR spectra proved the existence of a commensurate magnetic order while below 10 K, the shape of

  18. Splitting of the giant monopole resonance with deformation in the Sm nuclei

    SciTech Connect

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

    1980-11-24

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

  19. Dynamics of [C{sub 3}H{sub 5}N{sub 2}]{sub 6}[Bi{sub 4}Br{sub 18}] by means of {sup 1}H NMR relaxometry and quadrupole relaxation enhancement

    SciTech Connect

    Masierak, W.; Florek-Wojciechowska, M.; Oglodek, I.; Jakubas, R.; Privalov, A. F.; Kresse, B.; Fujara, F.; Kruk, D.

    2015-05-28

    {sup 1}H spin-lattice field cycling relaxation dispersion experiments in the intermediate phase II of the solid [C{sub 3}H{sub 5}N{sub 2}]{sub 6}[Bi{sub 4}Br{sub 18}] are presented. Two motional processes have been identified from the {sup 1}H spin-lattice relaxation dispersion profiles and quantitatively described. It has been concluded that these processes are associated with anisotropic reorientations of the imidazolium ring, characterized by correlation times of the order of 10{sup −8} s-10{sup −9} s and of about 10{sup −5} s. Moreover, quadrupole relaxation enhancement (QRE) effects originating from slowly fluctuating {sup 1}H-{sup 14}N dipolar interactions have been observed. From the positions of the relaxation maxima, the quadrupole coupling parameters for the {sup 14}N nuclei in [C{sub 3}H{sub 5}N{sub 2}]{sub 6}[Bi{sub 4}Br{sub 18}] have been determined. The {sup 1}H-{sup 14}N relaxation contribution associated with the slow dynamics has been described in terms of a theory of QRE [Kruk et al., Solid State Nucl. Magn. Reson. 40, 114 (2011)] based on the stochastic Liouville equation. The shape of the QRE maxima (often referred to as “quadrupole peaks”) has been consistently reproduced for the correlation time describing the slow dynamics and the determined quadrupole coupling parameters.

  20. Investigation of H-bonding and halogen-bonding effects in dichloroacetic acid: DFT calculations of NQR parameters and QTAIM analysis.

    PubMed

    Esrafili, Mehdi D

    2012-12-01

    A theoretical study was performed to examine hydrogen and halogen bonds properties in gas phase and crystalline dichloroacetic acid (DCAA). The specific pattern of O-H???O, C-H???O, HCl, Cl???O and Cl???Cl interactions in DCAA dimers is described within the quantum theory of atoms in molecules (QTAIM) formalism. Based on QTAIM results, a partial covalent character is attributed to the O-H???O hydrogen bonds in DCAA, whereas all the C-H???O, ClO and Cl???Cl intermolecular interactions are weak and basically electrostatic in nature. MP2/6-311++G** calculations indicate that the interaction energies for DCAA dimers lie in the range between -0.40 and -14.58kcalmol(-1). One of the most important results of this study is that, according to energy decomposition analyses, halogen bonds are largely dependent on both electrostatic and dispersion interactions. For those nuclei participating in the hydrogen-bonding and halogen-bonding interactions, nuclear quadrupole coupling constants exhibit significant changes on going from the isolated molecule model to the crystalline DCAA. Of course, the magnitude of these changes at each nucleus depends directly on its amount of contribution to the interactions. PMID:22736221

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

    SciTech Connect

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

    1988-01-01

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

  2. Use of phase information with a stepper motor to control frequency for tuning system of the Front End Test Stand Radio Frequency Quadrupole at Rutherford Appleton Laboratory

    NASA Astrophysics Data System (ADS)

    Alsari, S.; Aslaninejad, M.; Pozimski, J.

    2015-03-01

    For the Front End Test Stand (FETS) linear accelerator project at the Rutherford Appleton Laboratory in the UK, a 4 m, 4 vanes Radio Frequency Quadrupole (RFQ) with a resonant frequency of 324 MHz has been designed. The RF power feeding the RFQ gives rise to the temperature increase in the RFQ, which in turn, results in shifting the resonant frequency of the RFQ. The frequency shift and the stability in the RFQ frequency can be maintained based on the reflected power or signal phase information. We have, however, investigated restoration of the RFQ nominal frequency based on the RF signal phases driving a stepper motor. The concept and the system set-up and electronics are described in detail. Results of the measurements indicating the full restoration of the RFQ nominal frequency based on the RF signal phases and stepper motor are presented. Moreover, measured sensitivity of tuner with respect to its position is given.

  3. Electric quadrupole transition probabilities and line strengths of Ti{sup 11+}

    SciTech Connect

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

    2014-07-15

    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 HartreeFock 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.

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

    SciTech Connect

    Bossert, R.; Lietzke, A.; McInturff, A.D.; Scanlan, R.; LHC Collaboration

    1997-04-01

    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.

  5. The effect of vacancy ordering on quadrupole shifts in Mssbauer spectra of maghemite.

    PubMed

    Spiers, K M; Paganin, D M; Cashion, J D

    2011-05-01

    Electric field gradient (EFG) lattice sums for the vacancy-disordered and vacancy-ordered forms of maghemite were evaluated using a point charge model. The calculated EFGs produced a wide range of magnitudes and principal directions for the quadrupole interaction for both forms of maghemite. Small perturbations of the crystallographic parameters were shown to have a significant effect on the quadrupole shift. The effects observed were significant enough to show that quadrupole shifts should be considered when fitting the Mssbauer spectra of maghemite. PMID:21493972

  6. Alternate Oscillation between Scissors and Quadrupole Modes in Sodium Bose-Einstein Condensates

    NASA Astrophysics Data System (ADS)

    Yamazaki, Masahiro; Wakayama, Kazuki; Harada, Miho; Morinaga, Atsuo

    2015-04-01

    Using an additional off-axis Helmholtz coil, we modulated the strength of a magnetic field at the center of a cloverleaf trap for sodium Bose-Einstein condensates so that it passed through zero for a few milliseconds. At a modulation time of 1 ms, a scissors mode and a high-lying quadrupole mode were generated independently, which had the same Landau damping rates of 39(10) 1/s. However, at 2 ms, alternate oscillation between the scissors mode and the high-lying quadrupole mode, whose frequency was twice that of the scissors mode, was observed with the frequency of the low-lying quadrupole mode.

  7. Nitrogen Nuclear Quadrupole Interactions in RDX, ?-HMX and Cocaine Systems

    NASA Astrophysics Data System (ADS)

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

    1997-03-01

    Using the Hartree-Fock-Roothaan procedure, the nuclear quadrupole interactions (NQI) of the 14N (I = 1) nucleus in the energetically important molecules RDX, ?-HMX and the physiologically important molecule Cocaine, are studied. The coupling constants (e2 q Q) and asymmetry parameters (?) for the three ring nitrogens in RDX are found to be -5.671, -5.808 and -5.838 MHz and 0.542, 0.556 and 0.562, respectively, in good quantitative agreement with the experimental results of 5.735, 5.799 and 5.604 MHz for the magnitudes of e2qQ and 0.6215, 0.6146 and 0.6024 for ? obtained in the single crystal. For ?-HMX, where two sets of e2 q Q and ? are expected from symmetry considerations, our calculated values are -5.936 and -6.069 MHz for e2 q Q and 0.432 and 0.490 for ? , compared to experimentally measured magnitudes of 5.791 and 6.025 MHz and ?-values of 0.4977 and 0.5180, respectively, obtained in the single crystal. For Cocaine free base which contains only one 14N nucleus, our calculated values of e2 qQ and ? are -5.038 MHz and 0.067, in very good agreement with the experimental results of 5.0229 MHz for the magnitude of e2 q Q and 0.0395 for ?. Possible reasons for the small remaining differences between theory and experiment in e2 q Q and ? for all three systems and the significant differences in trends over the three nitrogens in RDX between theory and experiment are discussed. Also, the calculated quadrupole interaction parameters for the 14N nuclei in the NO2 groups outside the ring for both RDX and ?-HMX are presented with the hope that they will be measured in the future to provide a more complete understanding of the electron distributions in these systems.

  8. Development of a tandem-electrostatic-quadrupole accelerator facility for BNCT.

    PubMed

    Kreiner, A J; Thatar Vento, V; Levinas, P; Bergueiro, J; Di Paolo, H; Burlon, A A; Kesque, J M; Valda, A A; Debray, M E; Somacal, H R; Minsky, D M; Estrada, L; Hazarabedian, A; Johann, F; Suarez Sandin, J C; Castell, W; Davidson, J; Davidson, M; Giboudot, Y; Repetto, M; Obligado, M; Nery, J P; Huck, H; Igarzabal, M; Fernandez Salares, A

    2009-07-01

    In this work we describe the present status of an ongoing project to develop a tandem-electrostatic-quadrupole (TESQ) accelerator facility for accelerator-based (AB) BNCT at the Atomic Energy Commission of Argentina in Buenos Aires. The project final goal is a machine capable of delivering 30 mA of 2.4 MeV protons to be used in conjunction with a neutron production target based on the (7)Li(p,n)(7)Be reaction slightly beyond its resonance at 2.25 MeV. These are the specifications needed to produce sufficiently intense and clean epithermal neutron beams, based on the (7)Li(p,n)(7)Be reaction, to perform BNCT treatment for deep-seated tumors in less than an hour. An electrostatic machine is the technologically simplest and cheapest solution for optimized AB-BNCT. The machine being designed and constructed is a folded TESQ with a high-voltage terminal at 1.2 MV intended to work in air. Such a machine is conceptually shown to be capable of transporting and accelerating a 30 mA proton beam to 2.4 MeV. The general geometric layout, its associated electrostatic fields, and the acceleration tube are simulated using a 3D finite element procedure. The design and construction of the ESQ modules is discussed and their electrostatic fields are investigated. Beam transport calculations through the accelerator are briefly mentioned. Likewise, work related to neutron production targets, strippers, beam shaping assembly and patient treatment room is briefly described. PMID:19376714

  9. Multipole Surface Plasmon Resonance in Electrodeposited Gold Nanoparticles

    NASA Astrophysics Data System (ADS)

    Mandke, Mohanrao V.; Pathan, Habib M.

    2014-05-01

    Electrodeposition is a convenient, economical and template-free tool to create the gold nanostructures. A two-electrode electrochemical process is used for the deposition process. In this method by controlling the deposition time and electrode potential, nearly spherical and rod-like gold nanostructures were synthesized through the reduction of Chlorauric acid with citric acid as a complexing agent. Spherical gold nanostructures of different size around 2 nm to 30 nm and rod-like nanostructures with an aspect ratio 0.5 were grown directly on fluorine-doped tin oxide (FTO)-coated glass substrate. The growth mechanism of gold nanostructures is explained with the help of oriented attachment process. The contact angle measurement showed the hydrophilic nature of gold nanostructures using water with contact angle of about 56°. The optical properties showed a dipole, quadrupole and an octupole plasmon resonance mode at around 625 nm, 530 nm and 422 nm respectively. The dipole resonance peak extends further to give a broad absorption band in the near infrared region of electromagnetic waves. The refractive index sensitivity of gold nanoparticles in various solvents was investigated by calculating the red shift of surface plasmon resonance (SPR) peaks. The quadrupole plasmon resonance mode showed maximum SPR sensitivity as compared to dipole and octupole plasmon resonance mode. The controlled formation of gold nanoparticles with variation of SPR over wide range of visible region supports the potential applications in biosensors, nanoelectronics and plasmon enhanced light absorption in photovoltaics, etc.

  10. Magnetic Resonance

    Cancer.gov

    Focus Group on Magnetic Resonance Spectroscopy (MRS) in Clinical Oncology(April 1999) To explore the technical requirements for MRS and the application of hydrogen and multinuclear spectroscopy for tumor response to therapy.

  11. The Common Chlorine Nuclear Electric Quadrupole Coupling Tensor for Acyl Chlorides

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

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

  12. Rotational and magnetic shunt permanent magnet quadrupoles with variable magnetic strength

    SciTech Connect

    Vladimir Kashikhin et al.

    2002-03-28

    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.

  13. Field Quality Measurements and Analysis of the LARP Technology Quadrupole Models

    SciTech Connect

    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

    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.

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

    SciTech Connect

    Bossert, R.; Ambrosio, G.; Andreev, N.; Chlachidze, G.; Kashikhin, V. V.; Lamm, M.; Nobrega, F.; Novitski, I.; Tartaglia, M.; Yu, M.; Zlobin, A. V.

    2010-04-09

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

  15. A modified quadrupole mass spectrometer with custom RF link rods driver for remote operation

    NASA Technical Reports Server (NTRS)

    Tashbar, P. W.; Nisen, D. B.; Moore, W. W., Jr.

    1973-01-01

    A commercial quadrupole residual gas analyzer system has been upgraded for operation at extended cable lengths. Operation inside a vacuum chamber for the standard quadrupole nude head is limited to approximately 2 m from its externally located rf/dc generator because of the detuning of the rf oscillator circuits by the coaxial cable reactance. The advance of long distance remote operation inside a vacuum chamber for distances of 45 and 60 m was made possible without altering the quadrupole's rf/dc generator circuit by employing an rf link to drive the quadrupole rods. Applications of the system have been accomplished for in situ space simulation thermal/vacuum testing of sophisticated payloads.

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

    SciTech Connect

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

    2013-07-15

    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.

  17. Fission Quadrupole Mass Parameters in HF+BCS and HFB Methods

    SciTech Connect

    Baran, A.; Sheikh, J. A.; Staszczak, A.; Nazarewicz, Witold

    2009-01-01

    The self-consistent Hartree-Fock+BCS and Hartree-Fock-Bogoliubov methods are compared at large nuclear deformations. The calculations are carried out for the fission pathway and quadrupole mass parameter of ^{252}Fm.

  18. Modal response of 4-rod type radio frequency quadrupole linac

    SciTech Connect

    Chatterjee, Avik; Mahapatra, Abhijit; Mondal, Manas; Chakrabarti, Alok

    2009-10-15

    This paper deals with the analysis and experimental study of natural frequencies of vibration of a 4-rod type radio frequency quadrupole (RFQ) linear accelerator. The eigenvalue analysis of the structure has been done both analytically (multispan beam concept) as well as using blocked Lanczos eigenvalue finite element solver with an ability to extract the rigid body modes. This has been done in the mechanical design phase to find the level of agreement between the output of simplified analytical analysis results and the output of a commercial finite element method (FEM) solver, since a full scale RFQ structure is too complex to handle analytically. Experimental validation of the analysis results has been done on the physical 1.7 m RFQ at the installation site. The experimental data obtained were later analyzed and found to be in close agreement with the predicted frequencies in the lower frequency ranges. It gets more and more deviated in the higher frequency ranges. Also some frequencies were observed during experimentation, which were not found in the finite element analysis results. The source of those frequencies are to be further investigated as it may play a predominant role in the design high quality factor beam line cavities for higher operational efficiency.

  19. Ion mobility analyzer - quadrupole mass spectrometer system design

    NASA Astrophysics Data System (ADS)

    Cuna, C.; Leuca, M.; Lupsa, N.; Mirel, V.; Bocos-Bintintan, V.; Cuna, Stela; Cosma, V.; Tusa, Florina

    2009-08-01

    Because of their extremely high sensitivity for chemicals with elevated electronegativity or high proton affinity the ion mobility analysers are ideal for the ultra-trace detection of toxic or explosive chemicals, most of these situated often at concentration levels of sub-ppb (parts-per-billion). Ion mobility spectrometers (IMS) can be used to identify illicit drugs or environmental pollutants. Since resolution of an IMS is relatively low, to achieve an accurate identification of target analyte it is recommended to couple the IMS with a quadrupole mass spectrometer (QMS) or a time of flight mass spectrometer, acquiring in this way confirmatory information. This coupling is made through a specific interface. In this paper, an experimental model of such a tandem instrument, IMS-QMS is described. Accomplishment of this general purpose will be done, overcoming a series of specific issues. This implies the solving, using innovative solutions, of a series of complex issues: ensuring the stability of the ions beam generated by ion source; transfer with a good efficiency of the ionic current from IMS analyser to QMS; and realization of a special electronic circuitry which will be able to detect both positive and negative ions.

  20. A graphical approach to radio frequency quadrupole design

    NASA Astrophysics Data System (ADS)

    Turemen, G.; Unel, G.; Yasatekin, B.

    2015-07-01

    The design of a radio frequency quadrupole, an important section of all ion accelerators, and the calculation of its beam dynamics properties can be achieved using the existing computational tools. These programs, originally designed in 1980s, show effects of aging in their user interfaces and in their output. The authors believe there is room for improvement in both design techniques using a graphical approach and in the amount of analytical calculations before going into CPU burning finite element analysis techniques. Additionally an emphasis on the graphical method of controlling the evolution of the relevant parameters using the drag-to-change paradigm is bound to be beneficial to the designer. A computer code, named DEMIRCI, has been written in C++ to demonstrate these ideas. This tool has been used in the design of Turkish Atomic Energy Authority (TAEK)'s 1.5 MeV proton beamline at Saraykoy Nuclear Research and Training Center (SANAEM). DEMIRCI starts with a simple analytical model, calculates the RFQ behavior and produces 3D design files that can be fed to a milling machine. The paper discusses the experience gained during design process of SANAEM Project Prometheus (SPP) RFQ and underlines some of DEMIRCI's capabilities.

  1. Quadrupole beam-based alignment in the RHIC interaction regions

    SciTech Connect

    Ziegler, J.; Satogata, T.

    2011-03-28

    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.

  2. Asymptotics with a positive cosmological constant. III. The quadrupole formula

    NASA Astrophysics Data System (ADS)

    Ashtekar, Abhay; Bonga, Béatrice; Kesavan, Aruna

    2015-11-01

    Almost a century ago, Einstein used a weak field approximation around Minkowski spacetime to calculate the energy carried away by gravitational waves emitted by a time changing mass-quadrupole. However, by now there is strong observational evidence for a positive cosmological constant, Λ . To incorporate this fact, Einstein's celebrated derivation is generalized by replacing Minkowski spacetime with de Sitter spacetime. The investigation is motivated by the fact that, because of the significant differences between the asymptotic structures of Minkowski and de Sitter spacetimes, many of the standard techniques, including the usual 1 /r expansions, cannot be used for Λ >0 . Furthermore, since, e.g., the energy carried by gravitational waves is always positive in Minkowski spacetime but can be arbitrarily negative in de Sitter spacetime irrespective of how small Λ is, the limit Λ →0 can fail to be continuous. Therefore, a priori it is not clear that a small Λ would introduce only negligible corrections to Einstein's formula. We show that, while even a tiny cosmological constant does introduce qualitatively new features, in the end, corrections to Einstein's formula are negligible for astrophysical sources currently under consideration by gravitational wave observatories.

  3. Critical quadrupole fluctuations and collective modes in iron pnictide superconductors

    NASA Astrophysics Data System (ADS)

    Thorsmølle, V. K.; Khodas, M.; Yin, Z. P.; Zhang, Chenglin; Carr, S. V.; Dai, Pengcheng; Blumberg, G.

    2016-02-01

    The multiband nature of iron pnictides gives rise to a rich temperature-doping phase diagram of competing orders and a plethora of collective phenomena. At low dopings, the tetragonal-to-orthorhombic structural transition is closely followed by a spin-density-wave transition both being in close proximity to the superconducting phase. A key question is the nature of high-Tc superconductivity and its relation to orbital ordering and magnetism. Here we study the NaFe1 -xCoxAs superconductor using polarization-resolved Raman spectroscopy. The Raman susceptibility displays critical enhancement of nonsymmetric charge fluctuations across the entire phase diagram, which are precursors to a d -wave Pomeranchuk instability at temperature θ (x ) . The charge fluctuations are interpreted in terms of quadrupole interorbital excitations in which the electron and hole Fermi surfaces breathe in-phase. Below Tc, the critical fluctuations acquire coherence and undergo a metamorphosis into a coherent in-gap mode of extraordinary strength.

  4. Isobar Suppression by Photodetachment in a RF Quadrupole Ion Cooler

    NASA Astrophysics Data System (ADS)

    Liu, Yuan; Havener, A. C.; Havener, C. C.; Liang, F.; Beene, J. R.

    2004-11-01

    Selectively removing unwanted isobaric negative ions by electron photodetachment with a pulsed laser beam has been reported. However, the fraction of the negative ions removed was very small due to the short laser pulses used. Continuous wave (CW) lasers are desired for this application, but the photon flux available from CW lasers is too low. We have investigated a novel scheme for efficient suppression of isobar contaminants by photodetachment in a gas-filled RF-only quadrupole (RFQ) ion cooler. Simulation studies have shown that the RFQ ion cooler can significantly increase the laser-ion interaction time, thus, high efficiency of photodetachment is possible with commercially available CW lasers. A proof-of-principle experiment of Co^- and Ni^- ions is underway. A CW Nd:YAG laser beam at 1064 nm wavelength is used to selectively remove Co^- ions inside a RFQ ion cooler. A detailed description of the experimental setup and expected photodetachment efficiencies for Co^- and Ni^- ions will be given in this report. 1. D. Berkovits, et al., Nucl. Instrum. Meth. B52 (1990) 378-333.

  5. Errors and optics study of a permanent magnet quadrupole system

    NASA Astrophysics Data System (ADS)

    Schillaci, F.; Maggiore, M.; Rifuggiato, D.; Cirrone, G. A. P.; Cuttone, G.; Giove, D.

    2015-05-01

    Laser-based accelerators are gaining interest in recent years as an alternative to conventional machines [1]. Nowadays, energy and angular spread of the laser-driven beams are the main issues in application and different solutions for dedicated beam-transport lines have been proposed [2,3]. In this context a system of permanent magnet quadrupoles (PMQs) is going to be realized by INFN [2] researchers, in collaboration with SIGMAPHI [3] company in France, to be used as a collection and pre-selection system for laser driven proton beams. The definition of well specified characteristics, both in terms of performances and field quality, of the magnetic lenses is crucial for the system realization, for an accurate study of the beam dynamics and the proper matching with a magnetic selection system already realized [6,7]. Hence, different series of simulations have been used for studying the PMQs harmonic contents and stating the mechanical and magnetic tolerances in order to have reasonable good beam quality downstream the system. In this paper is reported the method used for the analysis of the PMQs errors and its validation. Also a preliminary optics characterization is presented in which are compared the effects of an ideal PMQs system with a perturbed system on a monochromatic proton beams.

  6. Hybrid permanent magnet quadrupoles for the Recycler Ring at Fermilab

    SciTech Connect

    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

    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.

  7. Miniature mass spectrometer systems based on a microengineered quadrupole filter.

    PubMed

    Malcolm, Andrew; Wright, Steven; Syms, Richard R A; Dash, Neil; Schwab, Marc-André; Finlay, Alan

    2010-03-01

    Two miniature mass spectrometer systems based on a microengineered quadrupole mass filter have been developed. One of the instruments has a footprint of 27 cm x 20 cm and is intended for laboratory use when space is at a premium. The other is portable and intended for use in the field. It is battery powered, weighs 14.9 kg, and is housed in a rugged case. This is the first example of a portable mass spectrometer incorporating an analyzer fabricated using microelectromechanical systems (MEMS) techniques. The starting material for construction of the filters is a bonded silicon on insulator substrate, which is selectively etched using batch processing techniques to form coupling optics and springs that accurately hold 0.5 mm diameter stainless steel rods in the required geometry. Assembled filters measure 35 mm x 6 mm x 1.5 mm and are mounted, together with an ion source and channeltron detector, in small, interchangeable cartridges, which plug into a 220 cm(3) vacuum chamber. Recovery from accidental contamination or when servicing is required can be achieved within 5-10 min, as the cartridge is easily exchanged with a spare. A potential application to environmental monitoring has been investigated. The headspace above water spiked with dibutyl mercaptan was sampled with a solid phase microextraction (SPME) fiber, which was then injected directly into the vacuum chamber of the mass spectrometer. Using this method, the limit of detection was found to be approximately 5 ppm for a 15 s sampling period. PMID:20108919

  8. Thermal activation of stored ions in a quadrupole ion trap

    SciTech Connect

    Herron, W.J.; Goeringer, D.E.; McLuckey, S.A.

    1995-12-31

    Trapped ion techniques offer a unique opportunity to probe the nature of isolated ions in the gas phase. The authors adapted an electrospray/atmospheric glow discharge quadrupole ion trap combination to allow for a heated vacuum system. By increasing the temperature and the average collisional energy, the authors studyied changes in the dissociation behavior and the ion-molecule reactivity of ions as a function of temperature. The temperature plays a role in both the activation of unimolecular fragmentation and desolvation phenomena. This set-up has allowed acquisition of ESI mass spectra of multiply-charged Horse Heart Myoglobin and exploration of its dissociation behavior as a function of bath gas temperature. Thermal activation which raises the internal energy of the ion, also affects intermolecular interactions such as the solvation of a multiply-charged ion by a large number of neutral species. Raising the temperature of multiply-charged species will {open_quotes}heat{close_quotes} them above the binding energy of the weakly bound neutral species, thus desolvating the ion. The authors have observed this process during the thermal activation of multiply-charged Horse Heart Myoglobin.

  9. Quadrupole collectivity in neutron-rich Cd isotopes

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

  10. Plasma laser characterization by electrostatic mass quadrupole analyzer

    NASA Astrophysics Data System (ADS)

    Torrisi, L.; Caridi, F.; Margarone, D.; Borrielli, A.

    2008-01-01

    A study of laser ablation of different metals (aluminium, zinc, tantalum and lead), in vacuum, by using 3 ns Nd:YAG laser radiation, at 532 nm wavelength, is reported. Laser pulse, at intensities of the order of 109 W/cm2, produces high non-isotropic emission of neutrals and ionic species. Mass quadrupole spectrometry, associated to electrostatic ion deflection, allows estimation of the energy distributions of the emitted species within the plume as a function of the incident laser energy. Neutrals show typical Boltzmann distributions while ions show Coulomb-Boltzmann-shifted distributions. The plasma characterization is rationalized in terms of kinetic energies of ejected particles, ion, electron and neutral temperatures, ion charge states, and plasma density. A special regard is given to the parameters which regulate the plasma temperature: the boiling point, the electron density and the ionization potentials of the ablated elements. The ion acceleration processes occurring inside the plasma due to the high electrical field generated in the non-equilibrium plasma conditions are presented and discussed.

  11. Effects of charge inhomogeneities on elementary excitations in La2-xSrxCuO₄

    DOE PAGESBeta

    Park, S. R.; Hamann, A.; Pintschovius, L.; Lamago, D.; Khaliullin, G.; Fujita, M.; Yamada, K.; Gu, G. D.; Tranquada, J. M.; Reznik, D.

    2011-12-12

    Purely local experimental probes of many copper oxide superconductors show that their electronic states are inhomogeneous in real space. For example, scanning tunneling spectroscopic imaging shows strong variations in real space, and according to nuclear quadrupole resonance (NQR) studies, the charge distribution in the bulk varies on the nanoscale. However, the analysis of the experimental results utilizing spatially averaged probes often ignores this fact. We have performed a detailed investigation of the doping dependence of the energy and linewidth of the zone-boundary Cu-O bond-stretching vibration in La2-xSrxCuO₄ by inelastic neutron scattering. Both our results as well as previously reported angle-dependentmore » momentum widths of the electronic spectral function detected by angle-resolved photoemission can be reproduced by including the same distribution of local environments extracted from the NQR analysis.« less

  12. Effects of charge inhomogeneities on elementary excitations in La2-xSrxCuO₄

    SciTech Connect

    Park, S. R.; Hamann, A.; Pintschovius, L.; Lamago, D.; Khaliullin, G.; Fujita, M.; Yamada, K.; Gu, G. D.; Tranquada, J. M.; Reznik, D.

    2011-12-12

    Purely local experimental probes of many copper oxide superconductors show that their electronic states are inhomogeneous in real space. For example, scanning tunneling spectroscopic imaging shows strong variations in real space, and according to nuclear quadrupole resonance (NQR) studies, the charge distribution in the bulk varies on the nanoscale. However, the analysis of the experimental results utilizing spatially averaged probes often ignores this fact. We have performed a detailed investigation of the doping dependence of the energy and linewidth of the zone-boundary Cu-O bond-stretching vibration in La2-xSrxCuO₄ by inelastic neutron scattering. Both our results as well as previously reported angle-dependent momentum widths of the electronic spectral function detected by angle-resolved photoemission can be reproduced by including the same distribution of local environments extracted from the NQR analysis.

  13. Set Up and Test Results for a Vibrating Wire System for Quadrupole Fiducialization

    SciTech Connect

    Not Available

    2010-11-29

    Quadrupoles will be placed between the undulator segments in LCLS to keep the electron beam focused as it passes through. The quadrupoles will be assembled with their respective undulator segments prior to being placed into the tunnel. Beam alignment will be used to center the quadrupoles, along with the corresponding undulators, on the beam. If there is any displacement between the undulator and the quadrupole axes in the assemblies, the beam will deviate from the undulator axis. If it deviates by more than 80{micro}m in vertical or 140{micro}m in horizontal directions, the undulator will not perform as required by LCLS. This error is divided between three sources: undulator axis fiducialization, quadrupole magnetic axis fiducialization, and assembly of the two parts. In particular, it was calculated that the quadrupole needs to be fiducialized to within 25{micro}m in both vertical and horizontal directions. A previous study suggested using a vibrating wire system for finding the magnetic axis of a quadrupole. The study showed that the method has high sensitivity (up to 1{micro}m) and laid out guidelines for constructing it. There are 3 steps in fiducializing the quadrupole with the vibrating wire system. They are positioning the wire at the magnet center (step 1), finding the wire with position detectors (step 2), and finding the quadrupole tooling ball positions relative to the position detector tooling balls (step 3). The following break up of error was suggested for the fiducialization steps: 10{micro}m for step 1 (finding the center), 20{micro}m for step 2 (finding the wire), and 10{micro}m for step 3 (tooling ball measurements). The purpose of this study is to investigate whether the vibrating wire system meets the requirements for LCLS. In particular, if it can reliably fiducialize a quadrupole magnetic center to within 25{micro}m in both vertical and horizontal directions. The behavior of individual system components is compared to the expected performance. A vibrating wire system was constructed to fiducialize the quadrupoles between undulator segments in the LCLS. This note studies the ability of the system to fulfill the fiducialization requirements.

  14. Set Up and Test Results for a Vibrating Wire System for Quadrupole Fiducialization

    SciTech Connect

    Levashov, Michael Y.

    2010-12-01

    Quadrupoles will be placed between the undulator segments in LCLS to keep the electron beam focused as it passes through. The quadrupoles will be assembled with their respective undulator segments prior to being placed into the tunnel. Beam alignment will be used to center the quadrupoles, along with the corresponding undulators, on the beam. If there is any displacement between the undulator and the quadrupole axes in the assemblies, the beam will deviate from the undulator axis. If it deviates by more than 80{micro}m in vertical or 140{micro}m in horizontal directions, the undulator will not perform as required by LCLS. This error is divided between three sources: undulator axis fiducialization, quadrupole magnetic axis fiducialization, and assembly of the two parts. In particular, it was calculated that the quadrupole needs to be fiducialized to within 25{micro}m in both vertical and horizontal directions. A previous study suggested using a vibrating wire system for finding the magnetic axis of a quadrupole. The study showed that the method has high sensitivity (up to 1{micro}m) and laid out guidelines for constructing it. There are 3 steps in fiducializing the quadrupole with the vibrating wire system. They are positioning the wire at the magnet center (step 1), finding the wire with position detectors (step 2), and finding the quadrupole tooling ball positions relative to the position detector tooling balls (step 3). The following break up of error was suggested for the fiducialization steps: 10{micro}m for step 1 (finding the center), 20{micro}m for step 2 (finding the wire), and 10{micro}m for step 3 (tooling ball measurements). The purpose of this study is to investigate whether the vibrating wire system meets the requirements for LCLS. In particular, if it can reliably fiducialize a quadrupole magnetic center to within 25{micro}m in both vertical and horizontal directions. The behavior of individual system components is compared to the expected performance. A vibrating wire system was constructed to fiducialize the quadrupoles between undulator segments in the LCLS. This note studies the ability of the system to fulfill the fiducialization requirements.

  15. The angular overlap model applied to the calculation of nuclear quadrupole interactions. Derivation of partial nuclear quadrupole interaction parameters for biological relevant ligands in cadmium complexes

    NASA Astrophysics Data System (ADS)

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

    1988-07-01

    By the application of the angular overlap model to the calculation of nuclear quadrupole interactions (NQI), it is shown that it is possible to predict the NQI for the111Cd nucleus in a cadmium complex with known coordination geometry. This fact makes it relevant to apply such calculations to nuclear quadrupole interaction data for111Cd substituted zinc enzymes. It is demonstrated that with an approximate knowledge about the geometry and type of protein ligands from X-ray diffractions, it is possible to extract knowledge about type and geometry of nonprotein ligands in zinc enzymes, such as coordination of water, anions, or substrate molecules.

  16. Performance of Nb3Sn quadrupole magnets under localized thermal load

    SciTech Connect

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

    2009-06-01

    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.

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

    SciTech Connect

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

    2011-07-05

    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.

  18. Compact IR Quadrupoles for Linear Colliders Based on Rutherford-type Cable

    SciTech Connect

    Lopes, M.L.; Kashikhin, V.S.; Kashikhin, V.V.; Zlobin, A.V.; /Fermilab

    2008-08-01

    The upcoming and disrupted beams in the interaction region (IR) of a linear collider are focused by doublets consisting of two small-aperture superconducting quadrupoles. These magnets need an effective compact magnetic shielding to minimize magnetic coupling between the two channels and sufficient temperature margin to withstand radiation-induced heat depositions in the coil. This paper presents conceptual designs of IR quadrupoles for linear colliders based on NbTi and Nb{sub 3}Sn Rutherford-type cables.

  19. Conceptual design of large-bore superconducting quadrupoles with active magnetic shielding for the AHF

    SciTech Connect

    Vladimir Kashikhin et al.

    2003-06-09

    The Advanced Hydrotest Facility, under study by LANL, uses large-bore superconducting quadrupole magnets. In the paper we discuss the conceptual design of such quadrupoles using active shielding. The magnets are specified to achieve gradients of up to 24 T/m with a 28-cm warm bore and to have 0.01% field quality. Concepts for quench protection and the magnet cryosystems are also briefly discussed to confirm the viability of the proposed design.

  20. PERFORMANCE OF NB{sub 3}SN QUADRUPOLE MAGNETS UNDER LOCALIZED THERMAL LOAD

    SciTech Connect

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

    2010-04-09

    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.

  1. Magnetic field perturbation caused by bending vibrations of a quadrupole

    SciTech Connect

    Lebedev, V.; Stupakov, G.

    1992-07-01

    Bending vibration of a magnet body supported at two symmetric points is studied. The magnet is modeled by a slender elastic beam. The resonant frequencies are found and the averaged displacement of the magnet is calculated as a function of the frequency.

  2. Laser Resonator

    NASA Technical Reports Server (NTRS)

    Harper, L. L. (inventor)

    1983-01-01

    An optical resonator cavity configuration has a unitary mirror with oppositely directed convex and concave reflective surfaces disposed into one fold and concertedly reversing both ends of a beam propagating from a laser rod disposed between two total internal reflection prisms. The optical components are rigidly positioned with perpendicularly crossed virtual rooflines by a compact optical bed. The rooflines of the internal reflection prisms, are arranged perpendicularly to the axis of the laser beam and to the optical axes of the optical resonator components.

  3. Discrete resonances

    NASA Astrophysics Data System (ADS)

    Vivaldi, Franco

    2015-12-01

    The concept of resonance has been instrumental to the study of Hamiltonian systems with divided phase space. One can also define such systems over discrete spaces, which have a finite or countable number of points, but in this new setting the notion of resonance must be re-considered from scratch. I review some recent developments in the area of arithmetic dynamics which outline some salient features of linear and nonlinear stable (elliptic) orbits over a discrete space, and also underline the difficulties that emerge in their analysis.

  4. Contemporary research with nuclear resonance fluorescence at the S-DALINAC

    NASA Astrophysics Data System (ADS)

    Zweidinger, M.; Beck, T.; Beller, J.; Gayer, U.; Mertes, L.; Pai, H.; Pietralla, N.; Ries, P.; Romig, C.; Werner, V.

    2015-02-01

    In the last decades many nuclear resonance fluorescence experiments aiming for low-lying dipole excitations were performed at the Darmstadt High Intensity Photon Setup at S-DALINAC facility. On the electric dipole side, quadrupole-octupole coupled states and the Pygmy Dipole Resonance are of particular interest. On the magnetic dipole side, the so-called scissors mode is in the focus of interest. Furthermore, using the method of resonant self absorption, the decay behavior of J?= 1- states was investigated in 140Ce .

  5. Contemporary research with nuclear resonance fluorescence at the S-DALINAC

    SciTech Connect

    Zweidinger, M.; Beck, T.; Beller, J.; Gayer, U.; Mertes, L.; Pai, H.; Pietralla, N.; Ries, P.; Romig, C.; Werner, V.

    2015-02-24

    In the last decades many nuclear resonance fluorescence experiments aiming for low-lying dipole excitations were performed at the Darmstadt High Intensity Photon Setup at S-DALINAC facility. On the electric dipole side, quadrupole-octupole coupled states and the Pygmy Dipole Resonance are of particular interest. On the magnetic dipole side, the so-called scissors mode is in the focus of interest. Furthermore, using the method of resonant self absorption, the decay behavior of J{sup π} = 1{sup −} states was investigated in {sup 140}Ce.

  6. Fabrication and Test of 90-mm Nb3Sn Quadrupole Model Based on Dipole-type Collar

    SciTech Connect

    Bossert, R.; Andreev, N.; Chlachidze, G.; Kashikhin, V.S.; Kashikhin, V.V.; Lamm, M.J.; Nobrega, F.; Novitski, I.; Tartaglia, M.; Velev, G.; Zlobin, A.V.

    2010-07-29

    A series of 90-mm TQC quadrupole models with a collar-based mechanical structure has been fabricated and tested within the framework of the US-LHC Accelerator Research Program (LARP) using quadrupole-symmetric stainless steel collar laminations. This paper describes the design features, construction and test of TQC02Eb, the first TQC made with dipole-type collar and collaring techniques. Magnet test includes quench performance and field quality measurements at 4.5 and 1.9 K. Results of model performance for TQC quadrupoles based on dipole-type and quadrupole-type collars are compared and discussed.

  7. Rotating dipole and quadrupole field for a multiple cathode system

    SciTech Connect

    Chang, X.; Ben-Zvi, I.; Kewisch, J.; Litvinenko, V.; Meng, W.; Pikin, A.; Ptitsyn, V.; Rao, T.; Sheehy, B.; Skarita, J.; Wang, E.; Wu, Q.; Xin, T.

    2011-03-28

    A multiple cathode system has been designed to provide the high average current polarized electron bunches for the future electron-ion collider eRHIC [1]. One of the key research topics in this design is the technique to generate a combined dipole and quadrupole rotating field at high frequency (700 kHz). This type of field is necessary for combining bunches from different cathodes to the same axis with minimum emittance growth. Our simulations and the prototype test results to achieve this will be presented. The future eRHIC project, next upgrade of EHIC, will be the first electron-heavy ion collider in the world. For polarized-electron and polarized proton collisions, it requires a polarized electron source with high average current ({approx}50 mA), short bunch ({approx}3 mm), emittance of about 20 {micro}m and energy spread of {approx}1% at 10 MeV. The state-of-art polarized electron cathode can generate average current of about more than 1 mA, but much less than 50 mA. The current is limited by the quantum efficiency, lifetime, space charge and ultra-high vacuum requirement of the polarized cathode. A possible approach to achieve the 50 mA beam is to employ multiple cathodes, such as 20 cathodes, and combine the multiple bunched beams from cathodes to the same axis. We name it as 'Gatling gun' because its operations bear similarity to a multi-barrel Gatling gun. The electron spin direction is not affected by electric field but will follow to the direction of the magnetic bending. This requires that, to preserve the spin polarization from cathode, the fixed bending field after the solenoid and the rotating bending field in combiner must be either a pair of electric bendings or a pair of magnetic bendings. We choose the scheme with a pair of magnetic bendings because it is much easier than the scheme with a pair of electric bendings at our 200 keV electron energy level.

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

    SciTech Connect

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

    2014-01-29

    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.

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

    PubMed

    Rose, Katrin; Cottenier, Stefaan

    2012-08-28

    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 Mssbauer 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

  10. Dipole and quadrupole tests of the isotropy of gamma-ray burst locations

    NASA Technical Reports Server (NTRS)

    Briggs, Michael S.

    1993-01-01

    Dipole and quadrupole tests of the isotropy of locations on the sphere are discussed. The statistics (cos theta), the dipole moment to the Galactic center, and mean (sin-squared b - 1/3), the quadrupole moment about the Galactic plane, can be used to search for significant anisotropies in galactic coordinates. Such coordinate-system-based tests are the most powerful tests of dipole and quadrupole anisotropies in the particular coordinate system. Two statistics which have not been previously applied to gamma-ray burst data are described. The Rayleigh-Watson statistic measures the size of the dipole moment of the locations and the Bingham statistic measures the deviation of the eigenvalues of a quadrupole-like matrix from the values expected for isotropy. Tests based upon these two statistics search for dipole and quadrupole moments in spherical location data in a coordinate-system-independent, and thus model-independent, manner. They can detect an anisotropy in any direction and yield an analytic statistical significance to any detected anisotropy. The statistical tests are demonstrated herein using a variety of data sets.

  11. Electric Quadrupole Moments of the D States of Alkaline-Earth-Metal Ions

    SciTech Connect

    Sur, Chiranjib; Latha, K.V.P.; Sahoo, Bijaya K.; Chaudhuri, Rajat K.; Das, B.P.; Mukherjee, D.

    2006-05-19

    The electric quadrupole moment for the 4d {sup 2}D{sub 5/2} state of {sup 88}Sr{sup +}; one of the most important candidates for an optical clock, has been calculated using the relativistic coupled-cluster theory. This is the first application of this theory to determine atomic electric quadrupole moments. The result of the calculation is presented and the important many-body contributions are highlighted. The calculated electric quadrupole moment is (2.94{+-}0.07)ea{sub 0}{sup 2}, where a{sub 0} is the Bohr radius and e the electronic charge while the measured value is (2.6{+-}0.3)ea{sub 0}{sup 2}. This is so far the most accurate determination of the electric quadrupole moment for the above mentioned state. We have also calculated the electric quadrupole moments for the metastable 4d {sup 2}D{sub 3/2} state of {sup 88}Sr{sup +} and for the 3d {sup 2}D{sub 3/2,5/2} and 5d {sup 2}D{sub 3/2,5/2} states of {sup 43}Ca{sup +} and {sup 138}Ba{sup +}, respectively.

  12. Puzzle of the {sup 6}Li Quadrupole Moment: Steps toward Solving It

    SciTech Connect

    Blokhintsev, L.D.; Kukulin, V.I.; Pomerantsev, V.N.

    2005-07-01

    The problem of the origin of the quadrupole deformation in the {sup 6}Li ground state is investigated with allowance for the three-deuteron component of the {sup 6}Li wave function. Two long-standing puzzles related to the tensor interaction in the {sup 6}Li nucleus are known: that of an anomalous smallness of the {sup 6}Li quadrupole moment (being negative, it is smaller in magnitude than the {sup 7}Li quadrupole moment by a factor of 5) and that of an anomalous behavior of the tensor analyzing power T{sub 2q} in the scattering of polarized {sup 6}Li nuclei on various targets. It is shown that a large (in magnitude) negative exchange contribution to the {sup 6}Li quadrupole moment from the three-deuteron configuration cancels almost completely the 'direct' positive contribution due to the {alpha}d folding potential. As a result, the total quadrupole moment proves to be close to zero and highly sensitive to fine details of the tensor nucleon-nucleon interaction in the {sup 4}He nucleus and of its wave function.

  13. Continuous transmission line modeling for low and medium-energy linacs: DTL and RFQ. [DTL (Drift Tube Linac); RFQ (Radio Frequency Quadrupole)

    SciTech Connect

    Ke, M.K.

    1993-01-01

    A continuous transmission line model is developed for the low and medium energy linacs. Drift Tube Linac is simulated as a waveguide that is operated at the TM[sub 010] mode. Radio Frequency Quadrupole has been treated as a waveguide that is operated at the TE[sub 210] mode. These waveguide are filled with a medium that is uniform, homogeneous, but not isotropic. The DTL can be seen as a cylindrical resonator filled with an electrically uniaxial medium with the optic axis along the accelerating axis. The RFQ can be treated as a cylindrical resonator filled with a magnetically uniaxial medium with its optic axis along the accelerating axis. The RFQ and the DTL have no explicit boundaries between cells and all cells are strongly coupled together. Unlike the coupled resonator model, this model considers the whole long linac tank as a uniform cylindrical resonator. Instead of separated resonators, all individual cells having the same resonant frequency are combined in a transmission line. To simulate a DTL, stems supporting the drift-tubes in the outer tank are treated as shunt inductances that have no effect on the constant current structure and little effect on the current ramp structure. An L-C circuit simulating the straight post coupler shows that the sensitivity to the perturbations can be reduced and accelerating fields can be stabilized in a constant field DTL. To stabilize fields in a ramped gradient DTL (RGDTL), bent posts are needed. These bent posts can be modeled by as their equivalent circuits. Ignoring the wall loss, there is a good agreement between the results obtained and the experimental results of J.H. Billen carrying in Los Alamos National Laboratory. Beam loading in DTL and RFQ can be dealt with by the use of resistive elements in transmission line representations. Feeding has been simulated by current sources with a shunt conductances.

  14. Design and multiphysics analysis of a 176Â MHz continuous-wave radio-frequency quadrupole

    NASA Astrophysics Data System (ADS)

    Kutsaev, S. V.; Mustapha, B.; Ostroumov, P. N.; Barcikowski, A.; Schrage, D.; Rodnizki, J.; Berkovits, D.

    2014-07-01

    We have developed a new design for a 176 MHz cw radio-frequency quadrupole (RFQ) for the SARAF upgrade project. At this frequency, the proposed design is a conventional four-vane structure. The main design goals are to provide the highest possible shunt impedance while limiting the required rf power to about 120 kW for reliable cw operation, and the length to about 4 meters. If built as designed, the proposed RFQ will be the first four-vane cw RFQ built as a single cavity (no resonant coupling required) that does not require π-mode stabilizing loops or dipole rods. For this, we rely on very detailed 3D simulations of all aspects of the structure and the level of machining precision achieved on the recently developed ATLAS upgrade RFQ. A full 3D model of the structure including vane modulation was developed. The design was optimized using electromagnetic and multiphysics simulations. Following the choice of the vane type and geometry, the vane undercuts were optimized to produce a flat field along the structure. The final design has good mode separation and should not need dipole rods if built as designed, but their effect was studied in the case of manufacturing errors. The tuners were also designed and optimized to tune the main mode without affecting the field flatness. Following the electromagnetic (EM) design optimization, a multiphysics engineering analysis of the structure was performed. The multiphysics analysis is a coupled electromagnetic, thermal and mechanical analysis. The cooling channels, including their paths and sizes, were optimized based on the limiting temperature and deformation requirements. The frequency sensitivity to the RFQ body and vane cooling water temperatures was carefully studied in order to use it for frequency fine-tuning. Finally, an inductive rf power coupler design based on the ATLAS RFQ coupler was developed and simulated. The EM design optimization was performed using cst Microwave Studio and the results were verified using both hfss and ansys. The engineering analysis was performed using hfss and ansys and most of the results were verified using the newly developed cst Multiphysics package.

  15. Resonant behavior of dielectric objects (electrostatic resonances).

    PubMed

    Fredkin, D R; Mayergoyz, I D

    2003-12-19

    Resonant behavior of dielectric objects occurs at certain frequencies for which the object permittivity is negative and the free-space wavelength is large in comparison with the object dimensions. Unique physical features of these resonances are studied and a novel technique for the calculation of resonance values of permittivity, and hence resonance frequencies, is proposed. Scale invariance of resonance frequencies, unusually strong orthogonality properties of resonance modes, and a two-dimensional phenomenon of "twin" spectra are reported. The paper concludes with brief discussions of optical controllability of these resonances in semiconductor nanoparticles and a plausible, electrostatic resonance based, mechanism for nucleation and formation of ball lightning. PMID:14754117

  16. Giant multipole resonances from inelastic scattering of 152-MeV alpha particles

    SciTech Connect

    Bertrand, F.E.; Satchler, G.R.; Horen, D.J.; Wu, J.R.; Bacher, A.D.; Emery, G.T.; Jones, W.P.; Miller, D.W.; van der Woude, A.

    1980-11-01

    Giant resonance spectra have been measured for /sup 208/Pb, /sup 120/Sn, /sup 90/Zr, /sup 58/Ni, and /sup 46/Ti, using inelastic scattering of 152-MeV alpha particles. In addition to some low-lying states, the spectra were analyzed to yield separate peaks for the giant quadrupole resonance and giant monopole resonance, except in /sup 46/Ti, where no evidence was found for a giant monopole resonance. The results for the monopole resonance when compared to distorted-wave Born-approximation calculations show that approx.100% ( +- 20%) of the T=0, L=0 energy weighted sum rule is depleted for nuclei with A>90. For /sup 58/Ni only 40% of the monopole sum rule is found. The excitation energy of the giant monopole resonance follows the systematic trend approx.80 A/sup -1/3/ MeV. The data are also compared with folding model calculations using Tassie transition densities and an effective interaction derived from elastic data. Good agreement was obtained for low-lying quadrupole and octopole excitations, but this model yields considerably too little cross section for the monopole resonance. This probably indicates a deficiency in the Tassie model breathing mode transition density.

  17. Development of a GC/Quadrupole-Orbitrap Mass Spectrometer, Part I: Design and Characterization

    PubMed Central

    2015-01-01

    Identification of unknown compounds is of critical importance in GC/MS applications (metabolomics, environmental toxin identification, sports doping, petroleomics, and biofuel analysis, among many others) and remains a technological challenge. Derivation of elemental composition is the first step to determining the identity of an unknown compound by MS, for which high accuracy mass and isotopomer distribution measurements are critical. Here, we report on the development of a dedicated, applications-grade GC/MS employing an Orbitrap mass analyzer, the GC/Quadrupole-Orbitrap. Built from the basis of the benchtop Orbitrap LC/MS, the GC/Quadrupole-Orbitrap maintains the performance characteristics of the Orbitrap, enables quadrupole-based isolation for sensitive analyte detection, and includes numerous analysis modalities to facilitate structural elucidation. We detail the design and construction of the instrument, discuss its key figures-of-merit, and demonstrate its performance for the characterization of unknown compounds and environmental toxins. PMID:25208235

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

    SciTech Connect

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

    2008-06-01

    Insertion quadrupoles with large bore and high gradient are required to upgrade the luminosity of the Large Hadron Collider (LHC). The US LHC Accelerator Research Program is developing Nb{sub 3}Sn technology for the upgrade. This effort includes a series of 1 m long Technology Quadrupoles (TQ), to demonstrate the reproducibility at moderate field, and High-gradient Quadrupoles (HQ) to explore the magnet performance limits in terms of peak fields, forces and stresses. The HQ models are expected to achieve peak fields of 15 T or higher. A coil aperture of 90 mm, corresponding to gradients above 300 T/m, was chosen as the baseline. Peak stresses above 150 MPa are expected. Progress on the magnetic and mechanical design of the HQ models will be reported.

  19. A Superstrong Adjustable Permanent Magnet for the Final Focus Quadrupole in a Linear Collider

    SciTech Connect

    Mihara, T.

    2004-12-06

    A super strong permanent magnet quadrupole (PMQ) was fabricated and tested. It has an integrated strength of 28.5T with overall length of 10 cm and a 7mm bore radius. The final focus quadrupole of a linear collider needs a variable focal length. This can be obtained by slicing the magnet into pieces along the beamline direction and rotating these slices. But this technique may lead to movement of the magnetic center and introduction of a skew quadrupole component when the strength is varied. A ''double ring structure'' can ease these effects. A second prototype PMQ, containing thermal compensation materials and with a double ring structure, has been fabricated. Worm gear is selected as the mechanical rotating scheme because the double ring structure needs a large torque to rotate magnets. The structure of the second prototype PMQ is shown.

  20. 14 N quadrupole coupling in the microwave spectra of N-vinylformamide

    NASA Astrophysics Data System (ADS)

    Kannengieer, Raphaela; Stahl, Wolfgang; Nguyen, Ha Vinh Lam; Bailey, William C.

    2015-11-01

    The microwave spectra of two conformers, trans and cis, of the title compound were recorded using two molecular beam Fourier transform microwave spectrometers operating in the frequency range 2-40 GHz, and aimed at analyses of their 14 N quadrupole hyperfine structures. Rotational constants, centrifugal distortion constants, and nuclear quadrupole coupling constants ?aa and ?bb -?cc, were all determined with very high accuracy. Two fits including 176 and 117 hyperfine transitions were performed for the trans and cis conformers, respectively. Standard deviations of both fits are close to the measurement accuracy of 2 kHz. Complementary quantum chemical calculations - MP2/6-311++G(d,p) rotational constants, MP2/cc-pVTZ centrifugal distortion constants, and B3PW91/6-311+G(d,p)//MP2/6-311++G(d,p) nuclear quadrupole coupling constants - give spectroscopic parameters in excellent agreement with the experimental parameters.