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Sample records for 2h nuclear quadrupole

  1. 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.

  2. 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.

  3. The nuclear electric quadrupole moment of copper.

    PubMed

    Santiago, Régis 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

  4. A Comparative Time Differential Perturbed Angular Correlation Study of the Nuclear Quadrupole Interaction in HfF4·HF·2H2O Using 180mHf and 181Hf(β-)181Ta as Nuclear Probes: Is Ta an Innocent Spy?

    NASA Astrophysics Data System (ADS)

    Butz, Tilman; Das, Satyendra K.; Manzhur, Yurij

    2009-02-01

    We report on a comparative study of the nuclear quadrupole interaction of the nuclear probes 180mHf and 181Hf(β -)181Ta in HfF4・HF・2H2O using time differential perturbed angular correlations (TDPAC) at 300 K. For the first probe, assuming a Lorentzian frequency distribution, we obtained ωQ= 103(4) Mrad/s, an asymmetry parameter η = 0.68(3), a linewidth δ = 7.3(3.9)%, and full anisotropy within experimental accuracy. For the second probe, assuming a Lorentzian frequency distribution, we obtained three fractions: (1) with 56.5(7)%, ωQ= 126.64(4) Mrad/s and η = 0.9241(4) with a rather small distribution δ = 0.40(8)% which is attributed to HfF4・HF・2H2O; (2) with 4.6(4)%, ωQ = 161.7(3) Mrad/s and η = 0.761(4) assuming no line broadening which is tentatively attributed to a small admixture of Hf2OF6・H2O; (3) the remainder of 39.0(7)% accounts for a rapid loss of anisotropy and is modelled by a perturbation function with a sharp frequency multiplied by an exponential factor exp(-λ t) with λ = 0.55(2) ns-1. Whereas the small admixture of Hf2OF6・H2O escapes detection by the 180mHf probe, there is no rapid loss of roughly half the anisotropy as is the case with 181Hf(β -)181Ta. This loss could in principle be due to fluctuating electric field gradients originating from movements of nearest neighbour HF adducts and/or H2O molecules after nuclear transmutation to the foreign atom Ta which are absent for the isomeric probe. Alternatively, paramagnetic Ta ions could lead to fluctuating magnetic dipole fields which, when combined with fluctuating electric field gradients, could also lead to a rapid loss of anisotropy. In any case, Ta is not an "innocent spy" in this compound. Although 180mHf is not a convenient probe for conventional spectrometers, the use of fast digitizers and software coincidences would allow to use all γ -quanta in the stretched cascade which would greatly improve the efficiency of the spectrometer. 180mHf could also serve as a Pu

  5. 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.

  6. Nuclear quadrupole resonance single-pulse echoes.

    PubMed

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

    2008-09-01

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

  7. Table of nuclear electric quadrupole moments

    NASA Astrophysics Data System (ADS)

    Stone, N. J.

    2016-09-01

    This Table is a compilation of experimental measurements of static 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. Experimental data from all quadrupole moment measurements actually provide a value of the product of the moment and the electric field gradient [EFG] acting at the nucleus. Knowledge of the EFG is thus necessary to extract the quadrupole moment. A single recommended moment value is given for each state, based, for each element, wherever possible, upon a standard reference moment for a nuclear state of that element studied in a situation in which the electric field gradient has been well calculated. For several elements one or more subsidiary EFG/moment reference is required and their use is specified. The literature search covers the period to mid-2015.

  8. 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.

  9. 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.

  10. The Photon Polarization Parameter of 2H(n, γ)3H reaction with Inclusion of the Electric Quadrupole Contribution

    NASA Astrophysics Data System (ADS)

    Sadeghi, H.; Mosavi-Khansari, M.

    2014-09-01

    We use effective field theory (EFT) for the calculation of neutron—deuteron radiative capture at very low energies. We present here the use of EFT to calculate a low-energy photo-nuclear observable in three-body systems, the photon polarization parameter and fore—aft asymmetry at thermal neutron energies up to next-to-next to leading order (N2LO), with inclusion of the electric quadrupole contribution. The photon polarization parameter in total is found to be Rc = -0.421 ± 0.003 and is in good agreement with the other modern theoretical calculations based on modern nucleon—nucleon potentials. In comparison with our previous work, a satisfactory agreement with the available experimental data is found by inclusion of the electric quadrupole contribution.

  11. 14N nuclear quadrupole resonance in carcinostatic phosphamides

    NASA Astrophysics Data System (ADS)

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

    1980-02-01

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

  12. Theoretical 13C chemical shift, 14N, and 2H quadrupole coupling- constant studies of hydrogen bonding in L-alanylglycine dipeptide.

    PubMed

    Tafazzoli, M; Amini, S K

    2008-04-01

    (13)C chemical shieldings and (14)N and (2)H electric field gradient (EFG) tensors of L-alanylglycine (L-alagly) dipeptide were calculated at RHF/6-31 + + G** and B3LYP/6-31 + + G** levels of theory respectively. For these calculations a crystal structure of this dipeptide obtained from X-ray crystallography was used. Atomic coordinates of different clusters containing several L-alagly molecules were used as input files for calculations. These clusters consist of central and surrounding L-alagly molecules, the latter forming short, strong, hydrogen bonds with the central molecule. Since the calculations did not converge for these clusters, the surrounding L-alagly molecules were replaced by glycine molecules. In order to improve the accuracy of calculated chemical shifts and nuclear quadrupole coupling constants (NQCCs), different geometry-optimization strategies were applied for hydrogen nuclei. Agreement between calculated and experimental data confirms that our optimized coordinates for hydrogen nuclei are more accurate than those obtained by X-ray diffraction. PMID:18273875

  13. Proton zero-quantum 2D NMR of 2-propenenitrile aligned by an electric field. Determination of the 2H and 14N quadrupole coupling constants

    NASA Astrophysics Data System (ADS)

    Ruessink, B. H.; De Kanter, F. J. J.; MaClean, C.

    Zero-quantum NMR, selectively detected by 2D NMR, is applied to observe small 1H- 1H dipolar couplings in a polar liquid partially oriented by a strong electric field. The normal (single-quantum) 1H spectrum is severely broadened, which prevents the observation of small couplings. The results from the zero-quantum proton spectrum are used to calculate the 2H and 14N quadrupole coupling constants of 2-deutero-2-propenenitrile from the 2H and 14N NMR spectra.

  14. Nuclear quadrupole interaction of 199mHg mercaptides

    NASA Astrophysics Data System (ADS)

    Butz, T.; Völkel, Th.; Nuyken, O.

    1991-01-01

    The strength and symmetry of the nuclear quadrupole interaction of the following 199mHg mercaptides were measured at room temperature by-γ-γ-perturbed angular correlations: dithiotreitol (DTT), benzylmercaptan (BEM), 1,3-dimercaptobenzene (DMB), glycoldimercaptoacetate (GDMA), and an oligomer synthesized from 1,3-dimercaptobenzene and norbornadiene, having an average number of repeating units of seven and mercapto end groups (dimercaptotelechel:TEL7). The data suggest an almost linear SHgS bond in all cases.

  15. Determination of (2)H-enrichment of rat brain interstitial fluid and rat plasma by headspace-gas-chromatography - quadrupole-mass-spectrometry.

    PubMed

    Eberl, Anita; Altendorfer-Kroath, Thomas; Kollmann, Denise; Birngruber, Thomas; Sinner, Frank; Raml, Reingard; Magnes, Christoph

    2016-09-15

    (2)H2O as nonradioactive, stable marker substance is commonly used in preclinical and clinical studies and the precise determination of (2)H2O concentration in biological samples is crucial. However, aside from isotope ratio mass spectrometry (IRMS), only a very limited number of methods to accurately measure the (2)H2O concentration in biological samples are routinely established until now. In this study, we present a straightforward method to accurately measure (2)H-enrichment of rat brain interstitial fluid (ISF) and rat plasma to determine the relative recovery of a cerebral open flow microperfusion (cOFM) probe, using headspace-gas-chromatography - quadrupole-mass-spectrometry. This method is based on basic-catalyzed hydrogen/deuterium exchange in acetone and detects the (2)H-labelled acetone directly by the headspace GC-MS. Small sample volumes and limited number of preparation steps make this method highly competitive. It has been fully validated. (2)H enriched to 8800 ppm in plasma showed an accuracy of 98.9% and %Relative Standard Deviation (RSD) of 3.1 with n = 18 over three days and with two operators. Similar performance was obtained for cerebral ISF enriched to 1100 ppm (accuracy: 96.5%, %RSD: 3.1). With this highly reproducible method we demonstrated the successful employment of (2)H2O as performance marker for a cOFM probe. PMID:27402176

  16. Chlorine Nuclear Quadrupole Hyperfine Structure in the Vinyl - Chloride Complex

    NASA Astrophysics Data System (ADS)

    Leung, Helen O.; Marshall, Mark D.; Messinger, Joseph P.

    2015-06-01

    The microwave spectrum of the vinyl chloride--hydrogen chloride complex, presented at last year's symposium, is greatly complicated by the presence of two chlorine nuclei as well as an observed, but not fully explained tunneling motion. Indeed, although it was possible at that time to demonstrate conclusively that the complex is nonplanar, the chlorine nuclear quadrupole hyperfine splitting in the rotational spectrum resisted analysis. With higher resolution, Balle-Flygare Fourier transform microwave spectra, the hyperfine structure has been more fully resolved, but appears to be perturbed for some rotational transitions. It appears that knowledge of the quadrupole coupling constants will provide essential information regarding the structure of the complex, specifically the location of the hydrogen atom in HCl. Our progress towards obtaining values for these constants will be presented.

  17. Nuclear quadrupole moment of the {sup 99}Tc ground state

    SciTech Connect

    Errico, Leonardo; Darriba, German; Renteria, Mario; Tang Zhengning; Emmerich, Heike; Cottenier, Stefaan

    2008-05-15

    By combining first-principles calculations and existing nuclear magnetic resonance (NMR) experiments, we determine the quadrupole moment of the 9/2{sup +} ground state of {sup 99}Tc to be (-)0.14(3)b. This confirms the value of -0.129(20)b, which is currently believed to be the most reliable experimental determination, and disagrees with two earlier experimental values. We supply ab initio calculated electric-field gradients for Tc in YTc{sub 2} and ZrTc{sub 2}. If this calculated information would be combined with yet to be performed Tc-NMR experiments in these compounds, the error bar on the {sup 99}Tc ground state quadrupole moment could be further reduced.

  18. Nuclear-quadrupole optical hole burning in the stoichiometric material EuP5O14.

    PubMed

    Macfarlane, R M; Shelby, R M; Genack, A Z; Weitz, D A

    1980-11-01

    Hole burning, which is attributed to optical pumping of nuclear-quadrupole levels, has been observed in the stoichiometric rare-earth compound, EuP5O14 . The long lifetime of these holes (-60 min) implies slow nuclear-spin flip-flop rates. The small magnetic moment of Eu3+ has prevented conventional magnetic-resonance measurements on Eu3+ compounds, but hole burning provides a sensitive method for the optical detection of nuclear-magnetic resonance and nuclear-quadrupole resonance. We have used hole burning and optically detected nuclear-quadrupole resonance to determine quadrupole splittings in the ground (7Fo) and excited (5Do) states. PMID:19701271

  19. 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.

  20. 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.

  1. Triple quadrupole mass spectrometry as applied to flame diagnostics: study of the C2H 4/N 2O/Ar flame.

    PubMed

    Howard, S L; Newberry, J E; Sausa, R C; Miziolek, A W

    1993-02-01

    A recently developed research apparatus for characterization of low-pressure premixed flames has been developed and was used to characterize the C2H4/N2O/Ar flame at 20 torr. This instrument incorporates several diagnostic techniques in one apparatus so that individual techniques can be quantitatively compared and the usable detection range (both in terms of resolution and species detection) expanded. Results discussed in this report include mass analysis by triple quadrupole mass spectrometer and temperature measurement by thermocouple. Concentration profiles in the one-dimensional flame include CO, N2, and C2H4, at nominal m/z 28 as well as CO2 and N2O at m/z 44. PMID:24234794

  2. 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.

  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. Determination of nuclear quadrupole moments – An example of the synergy of ab initio calculations and microwave spectroscopy

    SciTech Connect

    Kellö, 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.

  5. Authentication of Medicines Using Nuclear Quadrupole Resonance Spectroscopy.

    PubMed

    Chen, Cheng; Zhang, Fengchao; Barras, Jamie; Althoefer, Kaspar; Bhunia, Swarup; Mandal, Soumyajit

    2016-01-01

    The production and sale of counterfeit and substandard pharmaceutical products, such as essential medicines, is an important global public health problem. We describe a chemometric passport-based approach to improve the security of the pharmaceutical supply chain. Our method is based on applying nuclear quadrupole resonance (NQR) spectroscopy to authenticate the contents of medicine packets. NQR is a non-invasive, non-destructive, and quantitative radio frequency (RF) spectroscopic technique. It is sensitive to subtle features of the solid-state chemical environment and thus generates unique chemical fingerprints that are intrinsically difficult to replicate. We describe several advanced NQR techniques, including two-dimensional measurements, polarization enhancement, and spin density imaging, that further improve the security of our authentication approach. We also present experimental results that confirm the specificity and sensitivity of NQR and its ability to detect counterfeit medicines. PMID:26841409

  6. 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

  7. Polarization enhanced Nuclear Quadrupole Resonance with an atomic magnetometer

    NASA Astrophysics Data System (ADS)

    Malone, Michael W.; Barrall, Geoffrey A.; Espy, Michelle A.; Monti, Mark C.; Alexson, Dimitri A.; Okamitsu, Jeffrey K.

    2016-05-01

    Nuclear Quadrupole Resonance (NQR) has been demonstrated for the detection of 14-N in explosive compounds. Application of a material specific radio-frequency (RF) pulse excites a response typically detected with a wire- wound antenna. NQR is non-contact and material specific, however fields produced by NQR are typically very weak, making demonstration of practical utility challenging. For certain materials, the NQR signal can be increased by transferring polarization from hydrogen nuclei to nitrogen nuclei using external magnetic fields. This polarization enhancement (PE) can enhance the NQR signal by an order of magnitude or more. Atomic magnetometers (AM) have been shown to improve detection sensitivity beyond a conventional antenna by a similar amount. AM sensors are immune to piezo-electric effects that hamper conventional NQR, and can be combined to form a gradiometer for effective RF noise cancellation. In principle, combining polarization enhancement with atomic magnetometer detection should yield improvement in signal-to-noise ratio that is the product of the two methods, 100-fold or more over conventional NQR. However both methods are even more exotic than traditional NQR, and have never been combined due to challenges in operating a large magnetic field and ultra-sensitive magnetic field sensor in proximity. Here we present NQR with and without PE with an atomic magnetometer, demonstrating signal enhancement greater than 20-fold for ammonium nitrate. We also demonstrate PE for PETN using a traditional coil for detection with an enhancement factor of 10. Experimental methods and future applications are discussed.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. The use of the pairing-quadrupole connections in PQM for application in nuclear systems

    NASA Astrophysics Data System (ADS)

    Drumev, K. P.; Georgieva, A. I.

    2016-03-01

    Within the algebraic realization of the Pairing-plus-Quadrupole Model /PQM/ in the framework of the Elliott's SU(3) Model,we present some particular applications for realistic nuclear systems. The probability distribution of the SU(3) basis states within the isovector, isoscalar and total pairing eigenstates is obtained through a numerical diagonalization of the PQM Hamiltonian in each limit. This allows the investigation of the interplay between the pairing and quadrupole interactions in the Hamiltonian of the PQM, containing all of them as limiting cases. The relative strengths of the dynamically symmetric quadrupole-quadrupole interaction with the considered types of pairing interactions are investigated systematically for systems like the 20Ne.

  13. Virial sum rules for nuclear electric shieldings and geometrical derivatives of dipole and quadrupole molecular moments

    NASA Astrophysics Data System (ADS)

    Lazzeretti, Paolo; Malagoli, Massimo; Zanasi, Riccardo

    1991-01-01

    The virial theorem has been used to derive sum rules for dipole- and mixed-dipole-quadrupole nuclear electric shieldings and corresponding geometrical derivatives of dipole and quadrupole moments in a molecule. Test calculations have been carried out on a series of first- and second-row hydrides. The virial sum rules can be effective tools to prove the accuracy of theoretical nuclear shieldings and analytic geometrical derivatives. As the latter are related to ir intensities, the virial sum rules can give important indications on the reliability of theoretical predictions for this spectroscopical parameter.

  14. An effect of nuclear electric quadrupole moments in thermonuclear fusion plasmas

    NASA Technical Reports Server (NTRS)

    De, B. R.; Srnka, L. J.

    1978-01-01

    Consideration of the nuclear electric quadrupole terms in the expression for the fusion Coulomb barrier suggests that this electrostatic barrier may be substantially modified from that calculated under the usual plasma assumption that the nuclei are electric monopoles. This effect is a result of the nonspherical potential shape and the spatial quantization of the nuclear spins of the fully stripped ions in the presence of a magnetic field. For monopole-quadrupole fuel cycles like p-B-11, the fusion cross-section may be substantially increased at low energies if the protons are injected at a small angle relative to the confining magnetic field.

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

    NASA Technical Reports Server (NTRS)

    Strow, L. L.

    1980-01-01

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

  16. Effect of magnetic quadrupole lens alignment on a nuclear microprobe resolution

    NASA Astrophysics Data System (ADS)

    Kolinko, S. V.; Ponomarev, A. G.

    2016-04-01

    The paper reports the research trends in developing probe-forming systems with high demagnification and analysis factors that limit a nuclear microprobe resolution. Parasitic aberrations caused by tilts and offsets of magnetic quadrupoles are studied in terms of their effect on probe parameters on a target. The most common arrangements of probe-forming systems such as a triplet and "Russian quadruplet" with separated geometry are considered. The accuracy prerequisites for the positioning of the quadrupoles are defined, and practical guidelines for alignment of probe-forming systems with high demagnification factors are suggested.

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

    SciTech Connect

    Bieron, Jacek; Pyykkoe, Pekka

    2005-03-01

    The multiconfiguration Dirac-Hartree-Fock (MCDHF) model has been employed to calculate the atomic expectation values responsible for the hyperfine splittings of the 7s7p {sup 3}P{sub 1,2} and {sup 1}P{sub 1} levels of radium. Calculated electric field gradients, together with the experimental electric quadrupole hyperfine structure constants, allow us to extract a nuclear electric quadrupole moment Q({sup 223}Ra) of 1.21(0.03) barn. This value is in good agreement with the semiempirical determination based on neutral radium hyperfine and fine structure, but differs from the latest result from an alkali-like radium ion.

  18. 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 χzz, 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 χzz 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.

  19. 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.

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

    SciTech Connect

    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 R{sub 1} 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 R{sub 1} 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 {sup 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 {sup 27}Al (S = 5/2) nuclei is also explained.

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

    NASA Astrophysics Data System (ADS)

    Hadipour, N. L.; Elmi, F.

    2003-03-01

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

  2. Nuclear Quadrupole Resonance Studies of Charge Distributions in Molecular Solids.

    NASA Astrophysics Data System (ADS)

    Greenbaum, Steven Garry

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

  3. The Nuclear Quadrupole Interaction of 204mPb in Lead Oxides

    NASA Astrophysics Data System (ADS)

    Friedemann, S.; Heinrich, F.; Haas, H.; Tröger, W.

    2004-12-01

    The nuclear quadrupole interaction of 204mPb in lead oxides has been measured by γ γ time differential perturbed angular correlation. Ab-initio calculations of the electric field gradients and X-ray diffraction allowed the assignment of the detected nuclear quadrupole interactions to the different Pb sites in the PbO phases litharge and massicote as well as in Pb3O4. The TDPAC probe 204mPb was produced with a 204Bi/204mPb-generator at the home laboratory at the University of Leipzig. The use of a high performance liquid chromatography system increased significantly the yield, the specific activity of 204mPb, and reduced the acidic concentration of the eluate.

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

    A general theory of lineshapes in nuclear quadrupole resonance (NQR), based on the stochastic Liouville equation, is presented. The description is valid for arbitrary motional conditions (particularly beyond the valid range of perturbation approaches) and interaction strengths. It can be applied to the computation of NQR spectra for any spin quantum number and for any applied magnetic field. The treatment presented here is an adaptation of the "Swedish slow motion theory," [T. Nilsson and J. Kowalewski, J. Magn. Reson. 146, 345 (2000), 10.1006/jmre.2000.2125] originally formulated for paramagnetic systems, to NQR spectral analysis. The description is formulated for simple (Brownian) diffusion, free diffusion, and jump diffusion models. The two latter models account for molecular cooperativity effects in dense systems (such as liquids of high viscosity or molecular glasses). The sensitivity of NQR slow motion spectra to the mechanism of the motional processes modulating the nuclear quadrupole interaction is discussed.

  5. Group theoretical classification of halogen nuclear quadrupole resonance spectra of distorted tetragonal antifluorite crystals

    NASA Astrophysics Data System (ADS)

    Morra, Rose M.; Armstrong, Robin L.

    A classification of the patterns of halogen nuclear quadrupole resonance lines resulting from distortions of the tetragonal R 2MX 6 structures C4 h5( I4/ m) and D4 h6( P4/ mnc) is given. Formal methods of group thepry are used to identify low symmetry space groups with the symmetries of vectors in an irreducible representation space of the high symmetry space group. Classification charts are presented which permit the identification of those space groups and primary order parameters which are compatible with particular halogen nuclear quadrupole resonance spectra. The discussion is limited to structural phase transitions involving the points of symmetry in the Brillouin zones of the high temperature phases. The sequences of structural transitions in K 2ReCl 6 and (NH 4) 2SnBr 6 are discussed as illustrations of the use of these charts.

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

    NASA Astrophysics Data System (ADS)

    Grechishkin, Vadim S.; Sinyavskii, Nikolai Ya

    1997-04-01

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

  7. The nuclear quadrupole interaction at inequivalent lattice sites in ammonium paramolybdate: A TDPAC study

    NASA Astrophysics Data System (ADS)

    Das, S. K.; Heinrich, F.; Butz, T.

    2006-09-01

    A nuclear quadrupole interaction (NQI) study using the time differential perturbed angular correlation (TDPAC) technique on ammonium paramolybdate (APM) has shown three inequivalent molybdenum sites in this compound which consists of seven MoO 6 polyhedra connected through edges. In this study the nuclear probe 99Mo was used to measure the γ- γ perturbed angular correlation of 99Tc on Mo-sites to obtain the quadrupole interaction parameters. The quadrupole interaction frequencies ( ωQ) for the three sites are 0.0224, 0.0386 and 0.0434 rad/ns and the asymmetry parameters ( η) of the electric field gradient (EFG) are 0.45, 0.18, and 0.58, respectively. The site assignment is based on the population ratios 4:2:1. The Mo atoms with the highest population show the lowest ωQ indicating that this set of polyhedra is "least" distorted or condensed. Besides the least squares fit, a cross-correlation algorithm has been used to analyze the experimental data to corroborate the fitted parameters and quoted errors. The derived NQI-parameters can be used for site assignments in other compounds built from condensed Mo-O octahedra.

  8. Nuclear Magnetic Dipole and Electric Quadrupole Moments: Their Measurement and Tabulation as Accessible Data

    SciTech Connect

    Stone, N. J.

    2015-09-15

    The most recent tabulations of nuclear magnetic dipole and electric quadrupole moments have been prepared and published by the Nuclear Data Section of the IAEA, Vienna [N. J. Stone, Report No. INDC(NDS)-0650 (2013); Report No. INDC(NDS)-0658 (2014)]. The first of these is a table of recommended quadrupole moments for all isotopes in which all experimental results are made consistent with a limited number of adopted standards for each element; the second is a combined listing of all measurements of both moments. Both tables cover all isotopes and energy levels. In this paper, the considerations relevant to the preparation of both tables are described, together with observations as to the importance and (where appropriate) application of necessary corrections to achieve the “best” values. Some discussion of experimental methods is included with emphasis on their precision. The aim of the published quadrupole moment 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. A table of recommended magnetic dipole moments is in preparation, with the same objective in view.

  9. Electric quadrupole polarizabilities of nuclear magnetic shielding in some small molecules.

    PubMed

    Ferraro, M B; Caputo, M C; Pagola, G I; Lazzeretti, P

    2008-01-28

    Computational procedures, based on (i) the Ramsey common origin approach and (ii) the continuous transformation of the origin of the quantum mechanical current density-diamagnetic zero (CTOCD-DZ), were applied at the Hartree-Fock level to determine electric quadrupole polarizabilities of nuclear magnetic shielding for molecules in the presence of a nonuniform electric field with a uniform gradient. The quadrupole polarizabilities depend on the origin of the coordinate system, but values of the magnetic field induced at a reference nucleus, determined via the CTOCD-DZ approach, are origin independent for any calculations relying on the algebraic approximation, irrespective of size and quality of the (gaugeless) basis set employed. On the other hand, theoretical estimates of the induced magnetic field obtained by single-origin methods are translationally invariant only in the limit of complete basis sets. Calculations of electric quadrupole polarizabilities of nuclear magnetic shielding are reported for H(2), HF, H(2)O, NH(3), and CH(4) molecules. PMID:18247940

  10. Electric quadrupole polarizabilities of nuclear magnetic shielding in some small molecules

    NASA Astrophysics Data System (ADS)

    Ferraro, M. B.; Caputo, M. C.; Pagola, G. I.; Lazzeretti, P.

    2008-01-01

    Computational procedures, based on (i) the Ramsey common origin approach and (ii) the continuous transformation of the origin of the quantum mechanical current density-diamagnetic zero (CTOCD-DZ), were applied at the Hartree-Fock level to determine electric quadrupole polarizabilities of nuclear magnetic shielding for molecules in the presence of a nonuniform electric field with a uniform gradient. The quadrupole polarizabilities depend on the origin of the coordinate system, but values of the magnetic field induced at a reference nucleus, determined via the CTOCD-DZ approach, are origin independent for any calculations relying on the algebraic approximation, irrespective of size and quality of the (gaugeless) basis set employed. On the other hand, theoretical estimates of the induced magnetic field obtained by single-origin methods are translationally invariant only in the limit of complete basis sets. Calculations of electric quadrupole polarizabilities of nuclear magnetic shielding are reported for H2, HF, H2O, NH3, and CH4 molecules.

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

    NASA Astrophysics Data System (ADS)

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

    2003-03-01

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

  12. Quantitative 35Cl nuclear quadrupole resonance in tablets of the antidiabetic medicine Diabinese.

    PubMed

    Tate, Elizabeth; Althoefer, Kaspar; Barras, Jamie; Rowe, Michael D; Smith, John A S; Pearce, Gareth E S; Wren, Stephen A C

    2009-07-01

    Pulsed (35)Cl nuclear quadrupole resonance (NQR) experiments have been performed on 250-mg tablets of the antidiabetic medicine Diabinese to establish the conditions needed for noninvasive quantitative analysis of the medicine in standard bottles. One important condition is the generation of a uniform radio-frequency (RF) field over the sample, which has been achieved by two designs of sample coil: one of variable pitch, and the other a resonator that has been fabricated from a single turn of copper sheet with a longitudinal gap bridged by tuning capacitors. The results from blind tests show that the number of tablets in a bottle could be predicted to within +/-3%. PMID:19492808

  13. 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.

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

    SciTech Connect

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

    2013-11-14

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

  15. 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.

  16. Probing the Electronic Environment of Methylindoles using Internal Rotation and (14)N Nuclear Quadrupole Coupling.

    PubMed

    Gurusinghe, Ranil M; Tubergen, Michael J

    2016-05-26

    High-resolution rotational spectra were recorded in the 10.5-21.0 GHz frequency range for seven singly methylated indoles. (14)N nuclear quadrupole hyperfine structure and spectral splittings arising from tunneling along the internal rotation of the methyl group were resolved for all indole species. The nuclear quadrupole coupling constants were used to characterize the electronic environment of the nitrogen atom, and the program XIAM was used to fit the barrier to internal rotation to the measured transition frequencies. The best fit barriers were found to be 277.1(2), 374.32(4), 414.(5), 331.6(2), 126.8675(15), 121.413(4), and 426(3) cm(-1) for 1-methylindole through 7-methylindole, respectively. The fitted barriers were found to be in good agreement with barriers calculated at the ωB97XD/6-311++G(d,p) level. The complete set of experimental barriers is compared to theoretical investigations of the origins of methyl torsional barriers and confirms that the magnitude of these barriers is an overall effect of individual hyperconjugative and structural interactions of many bonding/antibonding orbitals. PMID:27128828

  17. An approximate analytical expression for the nuclear quadrupole transverse relaxation rate of half-integer spins in liquids

    NASA Astrophysics Data System (ADS)

    Wu, Gang

    2016-08-01

    The nuclear quadrupole transverse relaxation process of half-integer spins in liquid samples is known to exhibit multi-exponential behaviors. Within the framework of Redfield's relaxation theory, exact analytical expressions for describing such a process exist only for spin-3/2 nuclei. As a result, analyses of nuclear quadrupole transverse relaxation data for half-integer quadrupolar nuclei with spin >3/2 must rely on numerical diagonalization of the Redfield relaxation matrix over the entire motional range. In this work we propose an approximate analytical expression that can be used to analyze nuclear quadrupole transverse relaxation data of any half-integer spin in liquids over the entire motional range. The proposed equation yields results that are in excellent agreement with the exact numerical calculations.

  18. Theory of electronic structure and nuclear quadrupole interactions in the BF3-NH3 complex and methyl derivatives

    NASA Astrophysics Data System (ADS)

    Pink, R. H.; Dubey, Archana; Mahato, Dip N.; Badu, S. R.; Scheicher, R. H.; Mahanti, Mahendra K.; Huang, M. B.; Saha, H. P.; Chow, Lee; Das, T. P.

    Magnetic Hyperfine and Nuclear Quadrupole Interactions (HPI and NQI) are now important tools for characterization of systems of interest in materials research and industry. Boron-Trifluoride is an inorganic compound that is very important in this respect as a catalyst in chemical physics research and industry, forming complexes in the process with compounds like ammonia, water and methyl alcohol. The present paper deals with the BP3-NH3 complex and methyl derivatives BP3NHx(CH3)3-x for which we have studied the electronic structures, binding energies, and 19F* (I=5/2) nuclear quadrupole interactions using the first-principles Hartree-Fock-Roothaan procedure combined with electron correlation effects. Our results for the 19F* nuclear quadrupole coupling constant (e 2qQ/h) in units of MHz compare well with experiment. Trends in the binding energies and NQI parameters between the complexes are discussed.

  19. Theory of electronic structure and nuclear quadrupole interactions in the BF3 NH3 complex and methyl derivatives

    NASA Astrophysics Data System (ADS)

    Pink, R. H.; Dubey, Archana; Mahato, Dip N.; Badu, S. R.; Scheicher, R. H.; Mahanti, Mahendra K.; Huang, M. B.; Saha, H. P.; Chow, Lee; Das, T. P.

    2007-04-01

    Magnetic Hyperfine and Nuclear Quadrupole Interactions (HFI and NQI) are now important tools for characterization of systems of interest in materials research and industry. Boron-Trifluoride is an inorganic compound that is very important in this respect as a catalyst in chemical physics research and industry, forming complexes in the process with compounds like ammonia, water and methyl alcohol. The present paper deals with the BF3 NH3 complex and methyl derivatives BF3NHx(CH3)3-x for which we have studied the electronic structures, binding energies, and 19F* ( I = 5/2) nuclear quadrupole interactions using the first-principles Hartree Fock Roothaan procedure combined with electron correlation effects. Our results for the 19F* nuclear quadrupole coupling constant ( e 2 qQ/ h) in units of MHz compare well with experiment. Trends in the binding energies and NQI parameters between the complexes are discussed.

  20. An approximate analytical expression for the nuclear quadrupole transverse relaxation rate of half-integer spins in liquids.

    PubMed

    Wu, Gang

    2016-08-01

    The nuclear quadrupole transverse relaxation process of half-integer spins in liquid samples is known to exhibit multi-exponential behaviors. Within the framework of Redfield's relaxation theory, exact analytical expressions for describing such a process exist only for spin-3/2 nuclei. As a result, analyses of nuclear quadrupole transverse relaxation data for half-integer quadrupolar nuclei with spin >3/2 must rely on numerical diagonalization of the Redfield relaxation matrix over the entire motional range. In this work we propose an approximate analytical expression that can be used to analyze nuclear quadrupole transverse relaxation data of any half-integer spin in liquids over the entire motional range. The proposed equation yields results that are in excellent agreement with the exact numerical calculations. PMID:27343483

  1. Study of nuclear quadrupole interactions and quadrupole Raman processes of 69Ga and 71Ga in a β-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 β-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 β-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.

  2. Communication through the phenyl ring: internal rotation and nuclear quadrupole splitting in p-halotoluenes

    NASA Astrophysics Data System (ADS)

    Shubert, V. Alvin; Schmitz, David; Schnell, Melanie

    2013-08-01

    The rotational spectra of three p-halotoluenes (chloro-, bromo- and iodo-) are reported in the frequency range 2-8.5 GHz, obtained with broadband Fourier-transform microwave spectroscopy. The recorded spectra are highly complicated due to low-barrier V 6 internal rotation of the methyl group as well as strong nuclear quadrupole coupling of the halogen atoms. However, these additional effects allow us, in a comparative manner, to study potential crosstalk of the two substituents via the phenyl ring. The rotational constants and other molecular parameters are reported and compared with quantum chemical calculations. The V 6 internal rotation barrier of the methyl group was found to be 145 GHz for both p-chlorotoluene species. We found that the magnitudes of the quadrupole coupling constants are increased in the halotoluenes compared to the halobenzenes. This increase is due to the +I inductive effect of the methyl group that injects additional electron density into the phenyl π-cloud, thus giving more electron density for the halogen atom to extract. This additional extraction makes the halogen-carbon bond more ionic than in the halobenzenes.

  3. (14) N nuclear quadrupole resonance study of piroxicam: confirmation of new polymorphic form V.

    PubMed

    Lavrič, Zoran; Pirnat, Janez; Lužnik, Janko; Puc, Uroš; Trontelj, Zvonko; Srčič, Stane

    2015-06-01

    A new polymorphic crystal form of piroxicam was discovered while preparing crystalline samples of piroxicam for (14) N nuclear quadrupole resonance (NQR) analysis. The new crystal form, designated as V, was prepared by evaporative recrystallization from dichloromethane. Three known polymorphic forms (I, II, and III) were also prepared. Our aim was to apply (14) N NQR to characterize the new polymorphic form of piroxicam and compare the results with those of the other known polymorphic forms. Additional analytical methods used for characterization were X-ray powder diffraction (XRPD), thermal analysis, and vibrational spectroscopy. For the first time, a complete set of nine characteristic (14) N NQR frequencies was found for each prepared polymorph of piroxicam. The consistent set of measured frequencies and calculated characteristic quadrupole parameters found for the new polymorphic form V is a convincing evidence that we are dealing with a new form. The already known piroxicam polymorphic forms were characterized similarly. The XRPD results were in accordance with the conclusions of (14) N NQR analysis. The performed study clearly demonstrates a strong potential of (14) N NQR method to be applied as a highly discriminative spectroscopic analytical tool to characterize polymorphic forms. PMID:25776345

  4. Reactivity Impact of 2H and 16O Elastic Scattering Nuclear Data on Critical Systems with Heavy Water

    NASA Astrophysics Data System (ADS)

    Roubtsov, D.; Kozier, K. S.; Chow, J. C.; Plompen, A. J. M.; Kopecky, S.; Svenne, J. P.; Canton, L.

    2014-04-01

    The accuracy of deuterium nuclear data is important for reactor physics simulations of heavy water (D2O) reactors. The elastic neutron scattering cross section data at thermal energies, σs,th, have been observed to have noticeable impact on the reactivity values in simulations of critical systems involving D2O. We discuss how the uncertainties in the thermal scattering cross sections of 2H(n,n)2H and 16O(n,n)16O propagate to the uncertainty of the calculated neutron multiplication factor, keff, in thermal critical assemblies with heavy water neutron moderator/reflector. The method of trial evaluated nuclear data files, in which specific cross sections are individually perturbed, is used to calculate the sensitivity coefficients of keff to the microscopic nuclear data, such as σs(E) characterized by σs,th. Large reactivity differences of up to ≃ 5-10 mk (500-1000 pcm) were observed using 2H and 16O data files with different elastic scattering data in MCNP5 simulations of the LANL HEU heavy-water solution thermal critical experiments included in the ICSBEP handbook.

  5. Time-reversal symmetry violation in molecules induced by nuclear magnetic quadrupole moments.

    PubMed

    Flambaum, V V; DeMille, D; Kozlov, M G

    2014-09-01

    Recent measurements in paramagnetic molecules improved the limit on the electron electric dipole moment (EDM) by an order of magnitude. Time-reversal (T) and parity (P) symmetry violation in molecules may also come from their nuclei. We point out that nuclear T, P-odd effects are amplified in paramagnetic molecules containing deformed nuclei, where the primary effects arise from the T, P-odd nuclear magnetic quadrupole moment (MQM). We perform calculations of T, P-odd effects in the molecules TaN, ThO, ThF+, HfF+, YbF, HgF, and BaF induced by MQMs. We compare our results with those for the diamagnetic TlF molecule, where the T, P-odd effects are produced by the nuclear Schiff moment. We argue that measurements in molecules with MQMs may provide improved limits on the strength of T, P-odd nuclear forces, on the proton, neutron, and quark EDMs, on quark chromo-EDMs, and on the QCD θ term and CP-violating quark interactions. PMID:25238355

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

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

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

  7. Nuclear quadrupole spin-lattice relaxation due to molecular reorientations in crystals with orientational disorder

    NASA Astrophysics Data System (ADS)

    Meriles, C. A.; Pérez, S. C.; Brunetti, A. H.

    1997-08-01

    p-chloronitrobenzene (PCNB) and p-chlorobromobenzene (PCBB) crystallize in the centrosymmetric space group P21/c with two molecules per unit cell. The space lattice will have an equal number of points with molecules facing in opposite directions. As a consequence, these compounds exhibit an orientational rigid disorder. In this work, we have measured the temperature dependence of the chlorine nuclear quadrupole spin-lattice relaxation time (T1), linewidth, and resonance frequency for both compounds for temperatures higher than 80 K. Both compounds exhibit an inhomogeneously broadened line shape and a "normal" Bayer-type temperature dependence of the resonance frequency. The analysis focuses on the identification of the dominant relaxation process at high temperatures (T>240 K in PCNB and T>260 K in PCBB). It is shown that T1(T) reflects the existence of 180° molecular reorientations through a modulation of the crystalline contribution to the electric field gradient.

  8. Nuclear quadrupole moment-induced Cotton-Mouton effect in molecules

    SciTech Connect

    Fu, Li-juan E-mail: juha.vaara@iki.fi; Vaara, Juha E-mail: juha.vaara@iki.fi

    2014-01-14

    Nuclear magneto-optic effects could make important contributions to novel, high-sensitivity, and high-resolution spectroscopic and imaging methods that provide nuclear site-specific structural and dynamic information on molecular and materials systems. Here we present a first-principles electronic structure formulation of nuclear quadrupole moment-induced Cotton-Mouton effect in terms of response theory, as well as ab initio and density-functional theory calculations of this phenomenon for a series of molecular liquids: H{sub 2}O, CH{sub 3}NO{sub 2}, CH{sub 3}CH{sub 2}OH, C{sub 6}H{sub 6}, C{sub 6}H{sub 12} (cyclohexane), HI, XeF{sub 2}, WF{sub 5}Cl, and Pt(C{sub 2}dtp){sub 2}. The roles of basis-set convergence, electron correlation, and relativistic effects are discussed. The estimated order of magnitude of the overall ellipticities induced to linearly polarized light is 10{sup −3}–10{sup −7} rad/(M cm) for fully spin polarized nuclei. The cases with the largest presently obtained ellipticities should be detectable with modern instrumentation in the Voigt magneto-optic setup, particularly for the heavy nuclei.

  9. The Microwave Spectrum of Imidazole; Complete Structure and the Electron Distribution from Nuclear Quadrupole Coupling Tensors and Dipole Moment Orientation

    NASA Astrophysics Data System (ADS)

    Christen, Dines; Griffiths, John H.; Sheridan, John

    1981-12-01

    Spectra have been measured for eleven isotopic forms of imidazole, including single substitutions at each nucleus in turn. A complete rs-structure is obtained. The ring structure is: N(1)-C(2) = 1.364 Å, C(2)-N(3) = 1.314 Å, N(3)-C(4) = 1.382 Å, C(4)-C(5) = 1.364 Å, C(5)-N(1) = 1.377 Å, ≮N(1)C(2)N(3) = 112.0°, ≮C(2)N(3)C(4) = 104.9°, ≮N(3)C(4)C(5) = 110.7°, ≮C(4)C(5)N(1) = 105.5° and ≮C(5)N(1)C(2) = 106.9°. The N(1)-H(1) distance is 0.998 Å, while the C-H distances are all very close to 1.078 Å. The bonds N(1)-H(1) and C(2)-H(2) lie close to the external bisectors of the respective ring angles, but C(4)-H(4) and C(5)-H(5) are each displaced by several degrees from these bisectors towards N(3) and N(1) respectively. The electric dipole moment is established as 3.67 (5) D from Stark effects, directed almost parallel with the line joining the nitrogen nuclei. The properties and orientations of the two 14N-nuclear quadrupole tensors have been investigated, in particular through the spectra of the two mono-14N-imidazoles.

  10. Effect of Intermolecular Hydrogen Bonding on the Nuclear Quadrupole Interaction in Imidazole and its Derivatives as Studied by ab initio Molecular Orbital Calculations

    NASA Astrophysics Data System (ADS)

    Nakamura, Nobuo; Masui, Hirotsugo; Ueda, Takahiro

    2000-02-01

    Ab initio Hartree-Fock molecular orbital calculations were applied to the crystalline imidazole and its derivatives in order to examine systematically the effect of possible N-H---N type hydrogen bond-ing on the nuclear quadrupole interaction parameters in these materials. The nitrogen quadrupole coupling constant (QCC) and the asymmetry parameter (η) of the electric field gradient (EFG) were found to depend strongly on the size of the molecular clusters, from single molecule, to dimer, trimer and to the infinite molecular chain, i.e., crystalline state, implying that the intermolecular N-H -N hydrogen bond affects significantly the electronic structure of imidazole molecule. A certain correla-tion between the QCC of 14N and the N-H bond distance R was also found and interpreted on the basis of the molecular orbital theory. However, we found that the value of the calculated EFG at the hy-drogen position of the N-H group, or the corresponding QCC value of 2 H, increases drastically as R-3 when R is shorter than about 0.1 nm, due probably to the inapplicability of the Gaussian basis sets to the very short chemical bond as revealed in the actual imidazole derivatives. We suggested that the ob-served N-H distances in imidazole derivatives should be re-examined.

  11. Electromagnetic theory of the nuclear interaction. Application to the deuteron {sup 2}H

    SciTech Connect

    Schaeffer, Bernard

    2012-06-20

    Bieler of the Rutherford laboratory imagined in 1924 a magnetic attraction equilibrating an electrostatic repulsion between the protons. Since the discovery of the neutron and the magnetic moments of the nucleons proving that the neutron contains electric charges, nobody, as far as I know, has tried to apply electromagnetism to the nuclear interaction. The electrostatic and magnetic interactions are completely neglected except for a mean Coulomb repulsion. As it is well known, there is an attraction between an electric charge and a neutral conductor. In the neutron, the positive charges are repelled and the negative charges attracted by a nearby proton. There is a net attraction explaining quantitatively the so-called strong force as it is shown in this paper. In the deuteron, the magnetic repulsion equilibrates the electrostatically induced neutron-proton attraction. The experimental value (- 2.2 MeV) is surrounded by - 1.6 MeV and - 2.5 MeV, depending on the calculation method. No arbitrary fitting parameter is used, only physical constants: it is a true ab initio calculation. The theoretical ratio between nuclear and chemical energies has been found to be (m{sub p}/m{sub e}{alpha}), proving that the usual assumption that the electromagnetic interaction is too feeble to predict the nuclear interaction is incorrect.

  12. CP-violating effect of the Th nuclear magnetic quadrupole moment: accurate many-body study of ThO.

    PubMed

    Skripnikov, L V; Petrov, A N; Titov, A V; Flambaum, V V

    2014-12-31

    Investigations of CP violation in the hadron sector may be done using measurements in the ThO molecule. Recent measurements in this molecule improved the limit on the electron electric dipole moment (EDM) by an order of magnitude. Another time-reversal (T) and parity (P)-violating effect in 229ThO is induced by the nuclear magnetic quadrupole moment. We perform nuclear and molecular calculations to express this effect in terms of the strength constants of T, P-odd nuclear forces, neutron EDM, QCD vacuum angle θ, quark EDM, and chromo-EDM. PMID:25615324

  13. a Microwave Spectroscopic Study of Methylated Indoles: Internal Rotation and Nuclear Quadrupole Coupling

    NASA Astrophysics Data System (ADS)

    Gurusinghe, Ranil; Tubergen, Michael

    2014-06-01

    The barrier to methyl internal rotation of an asymmetric two ring system depends on the position of the methyl substitution. A cavity based Fourier transform microwave spectrometer was used to record rotational spectra of different methyl substituted indoles in the range of 10.5 - 20 GHz. About 160 hyperfine components arising from about 30 rotational transitions were assigned for each 1- and 3-methylindole. The program XIAMa was used to fit the rotational constants, distortion constants, nuclear quadrupole coupling constants and barrier to internal rotation to the measured transition frequencies of the A and E internal rotation states. The best fit values for the rotational constants are A = 2651.12(2) MHz, B = 1305.266(2) MHz, C = 879.800(2) MHz for 1-methylindole and A = 2603.7224(5) MHz, B = 1268.7886(1) MHz, C = 857.8091(1) MHz for 3-methylindole. The different values observed for the barrier to internal rotation, 279.8(3) wn for 1-methylindole and 433(1) wn for 3-methylindole, may be due to the different rotor axis lengths and differences in local π-electron density. Progress on the assignment of additional methylated indoles will also be presented. aH. Hartwig and H. Dreizler, Z. Naturforsch, 51a, 923 - 932.

  14. Nuclear quadrupole coupling constants for N2O: experiment and theory.

    PubMed

    Brown, Alex; Wasylishen, Roderick E

    2012-10-01

    The nuclear quadrupole coupling constants (NQCCs) for the nitrogen and oxygen nuclei in N(2)O have been determined using a variety of computational methods (MP2, QCISD, DFT with B3LYP, PBE0, and B3PW91 functionals, CCSD, CCSD(T), CASSCF, and MRCI) combined with correlation-consistent basis sets. When compared to the available experimental determinations, the results demonstrate that only CCSD(T) and MRCI methods are capable of accurately predicting the NQCCs of the central and terminal nitrogen atoms. The spin-rotation and magnetic shielding tensors have also been determined and compared to experimental measurements where available. (14)N and (17)O NMR relaxation data for N(2)O in the gas phase and a variety of solvents is reported. The increase in the ratio of (14)N spin-lattice relaxation times in solvent for the central and terminal nitrogens supports previous reports of the modification of the electric field gradients at these nuclei in van der Waals complexes. Ab initio computations for the linear FH···N(2)O complex confirm the large change in EFGs imposed by a single perturber. PMID:22954039

  15. 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.

  16. 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.

  17. Microwave Spectra of Furazan II. Nuclear Quadrupole Coupling in d1-Furazan

    NASA Astrophysics Data System (ADS)

    Stiefvater, Otto L.

    1988-06-01

    The nuclear quadrupole coupling constants for the two nitrogen atoms in monodeuterated furazan (C2HDN2O) were determined from the hyperfine structure of eight rotational transitions with low J-values. The coupling constants along the inertial axes are: χaa (2) = + 3.546(10) MHz, χaa (5) = -5.044(10) MHz, χbb (2) = -4.690(10) MHz, χbb (5) = + 3.900(10) MHz, χcc (2) = + 1.144(10) MHz, χcc (5) = + 1.144(10) MHz. In conjunction with structural information from the preceding study, these data yield the principal coupling constants, with 3er-uncertainties, as: χR(2/5) = - 5.53 (4) MHz, χT(2/5) = + 4.39(4)MHz, χR(2/5) = + 1.14(4) MHz. The radial electric field gradients deviate from the direction of the external bisector of the ring angle ONC by 24.6° towards the oxygen atom. These results are in qualitative agreement with previous work by NQR spectroscopy and with the results of ab initio molecular orbital calculations.

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

    NASA Astrophysics Data System (ADS)

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

    1993-03-01

    The nuclear quadrupole interaction (NQI) of111Cd substituted for Cu(II) on type-1 sites in blue copper proteins is characterized by high values of ω0 in the region of 300 Mrad/s, close to that for the catalytic zinc site in alcohol dehydrogenase. Type-1 Cu has usually two sulfur ligands and two nitrogen ligands and in some cases an oxygen ligand in either a distorted tetrahedral geometry or in a trigonal bipyramidal geometry. The near tetrahedral arrangement together with the ligand sphere containing the same number of sulfur ligands explains the value of ω0 in the blue copper proteins. The present work determined the partial NQI for methionine using the known structure of azurin. This value was then used in the angular overlap model to calculate the NQI for ascorbate oxidase the structure of which is also known and gave good agreement with experiment. NQI data for laccase and stellacyanin the structures of which are unknown, are also given.

  19. Dependence of nuclear quadrupole resonance transitions on the electric field gradient asymmetry parameter for nuclides with half-integer spins

    NASA Astrophysics Data System (ADS)

    Cho, Herman

    2016-09-01

    Allowed transition energies and eigenstate expansions have been calculated and tabulated in numerical form as functions of the electric field gradient asymmetry parameter for the zero field Hamiltonian of quadrupolar nuclides with I = 3 / 2 , 5 / 2 , 7 / 2, and 9 / 2. These results are essential to interpret nuclear quadrupole resonance (NQR) spectra and extract accurate values of the electric field gradient tensors. Applications of NQR methods to studies of electronic structure in heavy element systems are proposed.

  20. The temperature dependence of the nuclear quadrupole interaction of 44Ti(EC)44Sc in rutile

    NASA Astrophysics Data System (ADS)

    Butz, T.; Vianden, R.

    2013-05-01

    The temperature dependence of the Nuclear Quadrupole Interaction on 44Sc in rutile was measured by Time Differential Perturbed Angular Correlation in the temperature range from 300 K to 945 K. Whereas \\upomega _Q = eQV_zz/4hbar with Vzz denoting the largest component of the electric field gradient tensor in magnitude increases with increasing temperature, the asymmetry parameter η remains essentially constant. This observation fits into the systematic with other probes provided the sign of Vzz is negative.

  1. Dependence of nuclear quadrupole resonance transitions on the electric field gradient asymmetry parameter for nuclides with half-integer spins

    DOE PAGESBeta

    Cho, Herman

    2016-02-28

    Allowed transition energies and eigenstate expansions have been calculated and tabulated in numerical form as functions of the electric field gradient asymmetry parameter for the zero field Hamiltonian of quadrupolar nuclides with I = 3/2,5/2,7/2, and 9/2. These results are essential to interpret nuclear quadrupole resonance (NQR) spectra and extract accurate values of the electric field gradient tensors. Furthermore, applications of NQR methods to studies of electronic structure in heavy element systems are proposed.

  2. 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.

  3. Direct current superconducting quantum interference device spectrometer for pulsed nuclear magnetic resonance and nuclear quadrupole resonance at frequencies up to 5 MHz

    SciTech Connect

    TonThat, D.M.; Clarke, J. |

    1996-08-01

    A spectrometer based on a dc superconducting quantum interference device (SQUID) has been developed for the direct detection of nuclear magnetic resonance (NMR) or nuclear quadrupole resonance (NQR) at frequencies up to 5 MHz. The sample is coupled to the input coil of the niobium-based SQUID via a nonresonant superconducting circuit. The flux locked loop involves the direct offset integration technique with additional positive feedback in which the output of the SQUID is coupled directly to a low-noise preamplifier. Precession of the nuclear quadrupole spins is induced by a magnetic field pulse with the feedback circuit disabled; subsequently, flux locked operation is restored and the SQUID amplifies the signal produced by the nuclear free induction signal. The spectrometer has been used to detect {sup 27}Al NQR signals in ruby (Al{sub 2}O{sub 3}[Cr{sup 3+}]) at 359 and 714 kHz. {copyright} {ital 1996 American Institute of Physics.}

  4. 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

  5. Zr-doped rutile TiO2: a nuclear quadrupole interaction study

    NASA Astrophysics Data System (ADS)

    Banerjee, D.; Das, S. K.; Das, P.; Thakare, S. V.; Butz, T.

    2010-04-01

    Role of Zr atom on the quadrupole interaction of 181Ta in rutile TiO2 has been investigated by time differential perturbed angular correlation (TDPAC) study. The quadrupole frequency remains same as that in the pure rutile TiO2 but its distribution increases with the amount of Zr. This indicates a metal-metal interaction between probe atom and Zr-atom in the nearest neighbour.

  6. 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.

  7. The application of frequency swept pulses for the acquisition of nuclear quadrupole resonance spectra

    NASA Astrophysics Data System (ADS)

    Rossini, Aaron J.; Hamaed, Hiyam; Schurko, Robert W.

    2010-09-01

    The acquisition of nuclear quadrupole resonance (NQR) spectra with wideband uniform rate and smooth truncation (WURST) pulses is investigated. 75As and 35Cl NQR spectra acquired with the WURST echo sequence are compared to those acquired with standard Hahn-echo sequences and echo sequences which employ composite refocusing pulses. The utility of WURST pulses for locating NQR resonances of unknown frequency is investigated by monitoring the integrated intensity and signal to noise of 35Cl and 75As NQR spectra acquired with transmitter offsets of several hundreds kilohertz from the resonance frequencies. The WURST echo sequence is demonstrated to possess superior excitation bandwidths in comparison to the pulse sequences which employ conventional monochromatic rectangular pulses. The superior excitation bandwidths of the WURST pulses allows for differences in the characteristic impedance of the receiving and excitation circuits of the spectrometer to be detected. Impedance mismatches have previously been reported by Marion and Desvaux [D.J.Y. Marion, H. Desvaux, J. Magn. Reson. (2008) 193(1) 153-157] and Muller et al. [M. Nausner, J. Schlagnitweit, V. Smrecki, X. Yang, A. Jerschow, N. Muller, J. Magn. Reson. (2009) 198(1) 73-79]. In this regard, WURST pulse sequences may afford an efficient new method for experimentally detecting impedance mismatches between receiving and excitation circuits, allowing for the optimization of solids and solution NMR and NQR spectrometer systems. The use of the Carr-Purcell Meiboom-Gill (CPMG) pulse sequence for signal enhancement of NQR spectra acquired with WURST pulses and conventional pulses is also investigated. Finally, the utility of WURST pulses for the acquisition of wideline NQR spectra is demonstrated by acquiring part of the 63/65Cu NQR spectrum of CuCN.

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

    NASA Astrophysics Data System (ADS)

    Gregorovič, Alan; Apih, Tomaž

    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.

  9. Nuclear Quadrupole Resonance Study of the Nitrogen Mustards and Local Anesthetics.

    NASA Astrophysics Data System (ADS)

    Buess, Michael Lee

    The density matrix description of pulsed nitrogen -14 nuclear quadrupole resonance (NQR) spin-echoes is presented. The parallel between this problem, when formulated in terms of the fictitious spin- 1/2 operators, and that of spin - 1/2 NMR spin-echoes in liquids is discussed along with the complications which arise in multiple-pulse NQR experiments in powders due to the random orientation of the electric field gradient tensors. The equipment and procedures involved in searching for, detecting and identifying NQR resonances using pulsed techniques are described. The ('14)N NQR spectra of several nitrogen mustard compounds in the solid state are reported and analyzed in the framework of the Townes and Dailey theory. For the aniline derivatives, a correlation exists between l -(sigma), l being the nitrogen lone-pair electron density and (sigma) the average N-C sigma bond electron density, and the enhanced Hammett sigma constant (sigma)('-). An improved correlation is obtained between l-(sigma) and (sigma)(,R)('-), which emphasizes the importance of resonance effects in determining l-(sigma). The increase of hydrolysis and alkylation rates with increasing values of l-(sigma) is in agreement with the identification of the cyclic immonium ion as the intermediate in the hydrolysis and alkylation processes of the aromatic nitrogen mustards. A possible correlation is noted between the ('35)Cl NQR spectra for some of the mustards and measures of toxic and antitumor activity. ('14)N NQR spectra for several local anesthetics in the solid state are also reported and analyzed using the Townes and Dailey approach. The changes in the electron distributions at various nitrogen sites, produced by protonating the tertiary amino nitrogen, are discussed and shown to be in general agreement with expectations bases on the increased electrophilic character of the protonated amino group.

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

    SciTech Connect

    Manninen, Pekka; Vaara, Juha; Pyykkoe, Pekka

    2004-10-01

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

  11. Nqrs Data for C8H9KO6 [C8H5KO4·2(H2O)] (Subst. No. 1092)

    NASA Astrophysics Data System (ADS)

    Chihara, H.; Nakamura, N.

    This document is part of Subvolume A `Substances Containing Ag … C10H15' of Volume 48 `Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III `Condensed Matter'. It contains an extract of Section `3.2 Data tables' of the Chapter `3 Nuclear quadrupole resonance data' providing the NQRS data for C8H9KO6 [C8H5KO4·2(H2O)] (Subst. No. 1092)

  12. SAS2H input for computing core activities of 4.5, 5.0, and 5.5 weight % {sup 235}U fuel for Sequoyah Nuclear Plant

    SciTech Connect

    Hermann, O.W.

    1994-08-01

    Sequoyah Nuclear Plant core activities at initial fuel enrichments of 4.5, 5.0, and 5.5 wt% {sup 235}U, required in nuclear safety evaluations, were computed by the SAS2H analysis sequence and the ORIGEN-S code within the SCALE-4.2 code system.

  13. Physical characterization and reactivity of the uranyl peroxide [UO2(η(2)-O2)(H2O)2]·2H2O: implications for storage of spent nuclear fuels.

    PubMed

    Mallon, Colm; Walshe, Aurora; Forster, Robert J; Keyes, Tia E; Baker, Robert J

    2012-08-01

    The unusual uranyl peroxide studtite, [UO(2)(η(2)-O(2))(H(2)O)(2)]·2H(2)O, is a phase alteration product of spent nuclear fuel and has been characterized by solid-state cyclic voltammetry. The voltammogram exhibits two reduction waves that have been assigned to the U(VI/V) redox couple at -0.74 V and to the U(V/IV) redox couple at -1.10 V. This potential shows some dependence upon the identity of the cation of the supporting electrolyte, where cations with larger ionic radii exhibit more cathodic reduction potentials. Raman spectroelectrochemistry indicated that exhaustive reduction at either potential result in a product that does not contain peroxide linkers and is likely to be UO(2). On the basis of the reduction potentials, the unusual behavior of neptunium in the presence of studtite can be rationalized. Furthermore, the oxidation of other species relevant to the long-term storage of nuclear fuel, namely, iodine and iodide, has been explored. The phase altered product should therefore be considered as electrochemically noninnocent. Radiotracer studies with (241)Am show that it does not interact with studtite so mobility will not be retarded in repositories. Finally, a large difference in band gap energies between studtite and its dehydrated congener metastudtite has been determined from the electronic absorption spectra. PMID:22813353

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

    NASA Astrophysics Data System (ADS)

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

    2005-10-01

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

  15. The prediction of the nuclear quadrupole splitting of 119Sn Mössbauer spectroscopy data by scalar relativistic DFT calculations.

    PubMed

    Krogh, Jesper W; Barone, Giampaolo; Lindh, Roland

    2006-06-23

    The electric field gradient components for the tin nucleus of 34 tin compounds of experimentally known structures and (119)Sn Mössbauer spectroscopy parameters were computed at the scalar relativistic density functional theory level of approximation. The theoretical values of the electric field gradient components were used to determine a quantity, V, which is proportional to the nuclear quadrupole splitting parameter (DeltaE). In a subsequent linear regression analysis the effective nuclear quadrupole moment, Q, was evaluated. The value of (11.9+/-0.1) fm(2) is a significant improvement over the non-relativistic result of (15.2+/-4.4) fm(2) and is in agreement with the experimental value of (10.9+/-0.8) fm(2). The average mean square error DeltaE(calcd)-DeltaE(exptl)=+/-0.3 mm s(-1) is a factor of two smaller than in the non-relativistic case. Thus, the approach has a quality which provides accurate support for the structure interpretation by (119)Sn spectroscopy. It was noted that geometry optimization at the relativistic level does not significantly increase the quality of the results compared with non-relativistic optimized structures. The accuracy in the approach called on us to consider the singlet-triplet state nature of the electronic structure of one of the investigated compounds. PMID:16671047

  16. 2H and 133Cs nuclear magnetic resonance study of Cs3D(SO4)2 single crystals in laboratory and rotating frames

    NASA Astrophysics Data System (ADS)

    Lim, Ae Ran; Kim, Sun Ha; Jeong, Se-Young

    2013-01-01

    To understand the physical properties of Cs3D(SO4)2 single crystals, in which deuterium replaces hydrogen, the temperature dependence of the NMR spectrum and the spin-lattice relaxation times in the laboratory frame, T1, and in the rotating frame, T1ρ, for 2H and 133Cs are investigated using Fourier transform nuclear magnetic resonance spectrometry. Our results for the 2H and 133Cs relaxation times provide no evidence of a phase transition. The strong temperature dependence of the 2H resonance lines is associated with deformation of the H(SO4)2- tetrahedra. Further, T1 and T1ρ for the 2H and 133Cs nuclei are governed by different mechanisms, which we discuss in terms of fast and slow motion.

  17. Characterization of the genomic structure and tissue-specific promoter of the human nuclear receptor NR5A2 (hB1F) gene.

    PubMed

    Zhang, C K; Lin, W; Cai, Y N; Xu, P L; Dong, H; Li, M; Kong, Y Y; Fu, G; Xie, Y H; Huang, G M; Wang, Y

    2001-08-01

    The human homologue of the Drosophila melanogaster orphan nuclear receptor fushi tarazu factor 1 (Ftz-F1), NR5A2 (hB1F), was initially identified as a regulatory factor that binds and activates enhancer II of hepatitis B virus. NR5A2 (hB1F) is expressed specifically in pancreas and liver, playing important roles in the regulation of several liver-specific genes. A detailed analysis on the genomic structure and promoter activity will greatly promote future studies on the function of the NR5A2 (hB1F) gene. In this report, a bacterial artificial chromosome clone and several phage clones covering the NR5A2 (hB1F) gene were isolated and the complete genomic sequence was obtained. Alignment of different cDNAs of the NR5A2 (hB1F) gene with the genomic sequence facilitated the delineation of its structural organization, which spans over 150 kb and consists of eight exons interrupted by seven introns. RT-PCR and 3'-RACE revealed that utilization of two polyadenylation signals results in the 3.8 and 5.2 kb transcripts that were observed previously. The transcription start site of the NR5A2 (hB1F) gene was mapped downstream of a canonical TATA box. An upstream fragment containing binding sites for several liver-specific and ubiquitous transcription factors exhibits hepatocyte-specific promoter activity. Transient transfections indicated that hepatocyte nuclear factors HNF1 and HNF3beta could activate NR5A2 (hB1F) promoter. PMID:11595170

  18. The nuclear quadrupole interaction at 111Cd and 181Ta sites in anatase and rutile TiO2: A TDPAC study

    NASA Astrophysics Data System (ADS)

    Das, Satyendra K.; Thakare, Sanjay V.; Butz, Tilman

    2009-03-01

    The nuclear quadrupole interaction of the I=5/2 state of the nuclear probes 111Cd and 181Ta in the anatase and rutile polymorphs of bulk TiO2 was studied using the time differential perturbed angular correlation (TDPAC). The fast-slow coincidence setup is based on the CAMAC electronics. For anatase, the asymmetry of the electric field gradient was eta=0.22(1) and a quadrupole interaction frequency: 44.01(3) Mrad/s was obtained for 181Ta. For rutile, the respective values are eta=0.56(1) and quadrupole frequency=130.07(9) Mrad/s. The values for rutile match closely with the literature values. In case of the 111Cd probe produced from the beta decay of 111Ag, the quadrupole interaction frequency and the asymmetry parameter for anatase was negligible. This indicates an unperturbed angular correlation in anatase. On the other hand for rutile, the quadrupole frequency is 61.74(2) Mrad/s and the asymmetry is 0.23(1) for 111Cd probe. The results have been interpreted in terms of the surrounding atom positions in the lattice and the charge state of the probe nucleus.

  19. The Nuclear Quadrupole Interaction of 187W(β-)187Re in W(VI)-EDTA Complexes

    NASA Astrophysics Data System (ADS)

    Sun, Guida; Liu, Weiqiao; Butz, Tilman

    2002-07-01

    The nuclear quadrupole interaction of 187W(β-)187Re in W(VI)-EDTA complexes at room temperature was determined by time differential perturbed angular correlations (TDPAC) to be VQ = 1270(8) MHz with an asymmetry parameter η= 0.403(4). While the coordination geometry of the Mo(VI)- EDTA complex is known, there appears to be none for the W-analogue. The rather similar asymmetry parameters for the 187W(β-)187Re in W(VI)-EDTA complex and for the 99Mo(β-)99Tc in Mo(VI)- EDTA complex, determined previously, supports the idea that the coordination geometries in the Moand W-complexes are similar

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

    PubMed

    Pérez, Silvina; Wolfenson, Alberto

    2012-02-01

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

  1. The position of deuterium in HOD—NNO as determined by structural and nuclear quadrupole coupling constants

    SciTech Connect

    Obenchain, Daniel A.; Frank, Derek S.; Novick, Stewart E.; Klemperer, William

    2015-08-28

    Rotational spectra of the weakly bound H{sub 2}O—N{sub 2}O complex and its HOD—N{sub 2}O isotopologue in a supersonic jet are reported. Rotational constants of the singly substituted deuterium in water and each singly substituted nitrogen-15 are presented. Combinations of isotopic data and high level ab initio calculations place the water in a similar position to those of the isoelectronic H{sub 2}O—CO{sub 2} complex, with a slight tilt of the OH towards the NNO axis. The deuterium nuclear quadrupole coupling constant places the deuterium on the O—H axis quasi-parallel to the NNO axis.

  2. 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.

  3. First-principles study of boron oxygen hole centers in crystals: Electronic structures and nuclear hyperfine and quadrupole parameters

    SciTech Connect

    Li Zucheng; Pan Yuanming

    2011-09-15

    The electronic structures, nuclear hyperfine coupling constants, and nuclear quadrupole parameters of fundamental boron oxygen hole centers (BOHCs) in zircon (ZrSiO{sub 4}, I4{sub 1}/amd) and calcite (CaCO{sub 3}, R3c) have been investigated using ab initio Hartree-Fock (HF) and various density functional theory (DFT) methods based on the supercell models with all-electron localized basis sets. Both exact HF exchange and appropriate correlation functionals are important in describing the BOHCs, and the parameter-free hybrid method based on Perdew, Burke, and Ernzerhof density functionals (PBE0) turns out to be the best DFT method in reproducing the electron paramagnetic resonance (EPR) data. Our results reveal three distinct types of simple-spin (S = 1/2) [BO{sub 3}]{sup 2-} centers in calcite: (i) the classic [BO{sub 3}]{sup 2-} radical with the D{sub 3h} symmetry and the unpaired spin equally distributed on the three oxygen atoms (i.e. the O{sub 3}{sup 5-} type); (ii) the previously reported [BO{sub 2}]{sup 0} center with the unpaired spin equally distributed on two of the three oxygen atoms (O{sub 2}{sup 3-}); and (iii) a new variety with {approx}90% of its unpaired spin localized on one (O{sup -}) of the three oxygen atoms with a long B-O bond (1.44 A). Calculations confirm the unusual [BO{sub 4}]{sup 0} center in zircon and show it to arise from a highly distorted configuration with 90% of the unpaired spin on one oxygen atom that has a considerably longer B-O bond (1.68 A) than its three counterparts (1.45 A). The calculated magnitudes and directions of {sup 11}B and {sup 17}O hyperfine coupling constants and nuclear quadrupole constants for the [BO{sub 4}]{sup 0} center in zircon are in excellent agreement with the 15 K EPR experimental data. These BOHCs are all characterized by a small negative spin density on the central B atom arising from spin polarization. Our calculations also demonstrate that the spin densities on BOHCs are affected substantially by

  4. Nuclear magnetic resonance study of the ferroelastic phase transition of order-disorder type in [N(C2H5)4]2CdCl4

    NASA Astrophysics Data System (ADS)

    Lim, Ae Ran; Kim, Min Soo; Lim, Kye-Young

    2016-08-01

    This study uses nuclear magnetic resonance (NMR) techniques to examine the detailed changes in [N(C2H5)4]2CdCl4 around its phase transition at the temperature TC = 284 K. The chemical shifts and spin-lattice relaxation times in the rotating frame (T1ρ) were determined from 1H magic angle spinning (MAS) NMR and 13C cross-polarization (CP)/MAS NMR spectra. The two sets of inequivalent 1H and 13C nuclei in CH3 and CH2 were distinguished. A ferroelastic phase transition was observed at TC, without structural symmetry change. The phase transition is mainly attributed to the orientational ordering of the [N(C2H5)4]+ cations, and the spectral splitting at low temperature is associated with different ferroelastic domains.

  5. The Position of Deuterium in the HOD-N_2O as Determined by Structural and Nuclear Quadrupole Coupling Constants

    NASA Astrophysics Data System (ADS)

    Obenchain, Daniel A.; Frank, Derek S.; Novick, Stewart E.; Klemperer, William

    2015-06-01

    A recent investigation of the HOD-N_2O complex measuring the OH + OD excited band in the near-IR was completed by Foldes et al. During this study, one of us (WAK) was contacted about the position of deuterium in the HOD-N_2O complex, as his group completed the original microwave study of H_2O-N_2O and its deuterated isotopologues ,2861. in 1992. The results of this microwave study did not give the orientation of HOD in the complex, however, we present here a supplementary study to the original microwave work using a Balle-Flygare cavity instrument, attempting to determine the orientation of HOD relative to the N_2O. In addition to a Kraitchman and a least-squares inertial structure fit of the molecule, we present the nuclear quadrupole coupling tensor of deuterium to determine the position of HOD in the complex. Földes, T; Lauzin, C.; Vanfleteren, T.; Herman, M.; Lièvin, J.; Didriche. K. High-resolution, near-infrared CW-CRDS and ab initio investigations of N_2O-HDO.Mol. Phys. 2015, 113(5),473-482. Zolandz, D.; Yaron, D.; Peterson, K.I.; Klemperer, W. Water in weak interactions: The structure of the water-nitrous oxide complex. J. Chem. Phys. 1992, 97

  6. High-Accuracy Calculation of cu Electric-Field Gradients: a Revision of the cu Nuclear Quadrupole Moment Value

    NASA Astrophysics Data System (ADS)

    Cheng, Lan; Matthews, Devin A.; Gauss, Jürgen; Stanton, John F.

    2015-06-01

    A revision of the value for the Cu nuclear quadrupole moment (NQM) is reported based on high-accuracy ab initio calculations on the Cu electric field gradients in the CuF and CuCl molecules. Electron-correlation effects have systematically been taken into account using a hierarchy of coupled-cluster methods including up to quadruple excitations. It is shown that the CCSD(T)_Λ method provides a more reliable treatment of triples corrections for Cu electric-field gradients than the ubiquitously applied CCSD(T) method, which is tentatively attributed to the importance of the wavefunction relaxation in the calculations of a core property. Augmenting large-basis-set CCSD(T)_Λ results with the remaining corrections obtained using additive schemes, including full triples contributions, quadruples contributions, zero-point vibrational corrections, spin-orbit corrections, as well as the correction from the Gaunt term, a new value of 209.7(50) mbarn for the Cu NQM has been obtained. The new value substantially reduces the uncertainty of this parameter in comparison to the standard value of 220(15) mbarn obtained from a previous muonic experiment.

  7. 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.

  8. Establishment of transgenic mice carrying the gene of human nuclear receptor NR5A2 (hB1F)

    PubMed Central

    Wang, Shui-Liang; Yang, Hua; Xie, You-Hua; Wang, Yuan; Li, Jian-Zhong; Wang, Long; Wang, Zhu-Gang; Fu, Ji-Liang

    2003-01-01

    AIM: Human hepatitis B virus enhancer II B1 binding factor (hB1F) was cloned and characterized as a novel member of the Ftz-F1 (NR5A) nuclear receptor subfamily. Although progresses have recently been made, its biological function remains largely unidentified. The aim of this study was to establish an hB1F transgenic mouse model to promote the functional study of hB1F. METHODS: Transgene fragments were microinjected into fertilized eggs of mice. The manipulated embryos were transferred into the oviducts of pseudopregnant female mice. The offsprings were identified by PCR and Southern blot analysis. Transgene expression was analyzed with RT-PCR and Western blot analysis. Transgenic founder mice were used to establish transgenic mouse lineages. The F1 and F2 mice were identified by PCR analysis. RESULTS: Seven mice were identified as carrying copies of transgene. RT-PCR and Western blotting results showed that the transgene was expressed in heart, liver, lung, kidney and stomach in one of the transgenic mouse lineages. Genetic analysis of the transgenic mice demonstrated that the transgene was integrated into the chromosome at a single site, and was transmitted stably. CONCLUSION: In this study we established an hB1F transgenic mouse model, which will facilitate the investigation of the biological function of hB1F in vivo. PMID:12800251

  9. Evaluation of Water Exchange Kinetics on [Ln(AAZTAPh-NO2)(H2O)q](x) Complexes Using Proton Nuclear Magnetic Resonance.

    PubMed

    Karimi, Shima; Tei, Lorenzo; Botta, Mauro; Helm, Lothar

    2016-06-20

    Water exchange kinetics on [Ln(AAZTAPh-NO2)(H2O)q](-) (Ln = Gd(3+), Dy(3+), or Tm(3+)) were determined by (1)H nuclear magnetic resonance (NMR) measurements. The number of inner-sphere water molecules was found to change from two to one when going from Dy(3+) to Tm(3+). The calculated water exchange rate constants obtained by variable-temperature proton transverse relaxation rates are 3.9 × 10(6), 0.46 × 10(6), and 0.014 × 10(6) s(-1) at 298 K for Gd(3+), Dy(3+), and Tm(3+), respectively. Variable-pressure measurements were used to assess the water exchange mechanism. The results indicate an associative and dissociative interchange mechanism for Gd(3+) and Dy(3+) complexes with ΔV(⧧) values of -1.4 and 1.9 cm(3) mol(-1), respectively. An associative activation mode (Ia or A mechanism) was obtained for the Tm(3+) complex (ΔV(⧧) = -5.6 cm(3) mol(-1)). Moreover, [Dy(AAZTAPh-NO2)(H2O)2](-) with a very high transverse relaxivity value was found as a potential candidate for negative contrast agents for high-field imaging applications. PMID:27227690

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

    NASA Technical Reports Server (NTRS)

    Norbury, John W.

    1992-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

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

  12. {sup 63}Cu and {sup 197}Au nuclear quadrupole moments from four-component relativistic density-functional calculations using correct long-range exchange

    SciTech Connect

    Thierfelder, Christian; Schwerdtfeger, Peter; Saue, Trond

    2007-09-15

    The electric field gradient in late transition metal compounds is incorrectly determined by most density functionals. We show that the coupling of short-range density functional based with long-range wave function based methods using a reparametrization of the Coulomb-attenuated Becke three-parameter Lee-Yang-Parr approximation gives reliable results for the electric field gradients of copper and gold for a series of compounds. This results in nuclear quadrupole moments of -0.208 b for {sup 63}Cu and +0.526 b for {sup 197}Au in good agreement with experimental values of -0.220(15) and +0.547(16)b, respectively.

  13. 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.

  14. Tracing bacterial metabolism using multi-nuclear (1H, 2H, and 13C) Solid State NMR: Realizing an Idea Initiated by James Scott

    NASA Astrophysics Data System (ADS)

    Cody, G.; Fogel, M. L.; Jin, K.; Griffen, P.; Steele, A.; Wang, Y.

    2011-12-01

    Approximately 6 years ago, while at the Geophysical Laboratory, James Scott became interested in the application of Solid State Nuclear Magnetic Resonance Spectroscopy to study bacterial metabolism. As often happens, other experiments intervened and the NMR experiments were not pursued. We have revisited Jame's question and find that using a multi-nuclear approach (1H, 2H, and 13C Solid State NMR) on laboratory cell culture has some distinct advantages. Our experiments involved batch cultures of E. coli (MG1655) harvested at stationary phase. In all experiments the growth medium consisted of MOPS medium for enterobacteria, where the substrate is glucose. In one set of experiments, 10 % of the water was D2O; in another 10 % of the glucose was per-deuterated. The control experiment used both water and glucose at natural isotopic abundance. A kill control of dead E. coli immersed in pure D2O for an extended period exhibited no deuterium incorporation. In both deuterium enriched experiments, considerable incorporation of deuterium into E. coli's biomolecular constituents was detected via 2H Solid State NMR. In the case of the D2O enriched experiment, 58 % of the incorporated deuterium is observed in a sharp peak at a frequency of 0.31 ppm, consistent with D incorporation in the cell membrane lipids, the remainder is observed in a broad peak at a higher frequency (centered at 5.4 ppm, but spanning out to beyond 10 ppm) that is consistent with D incorporation into predominantly DNA and RNA. In the case of the D-glucose experiments, 61 % of the deuterium is observed in a sharp resonance peak at 0.34 ppm, also consistent with D incorporation into membrane lipids, the remainder of the D is observed at a broad resonance peak centered at 4.3 ppm, consistent with D enrichment in glycogen. Deuterium abundance in the E. coli cells grown in 10 % D2O is nearly 2X greater than that grown with 10 % D-glucose. Very subtle differences are observed in both the 1H and 13C solid

  15. Probing the formation and evolution of comets via nuclear spin temperatures of C_2H_6, CH_3OH, CH_4, NH_3, and H_2O

    NASA Astrophysics Data System (ADS)

    Villanueva, G.; Mumma, M.; Bonev, B.; DiSanti, M.; Paganini, L.; Magee-Sauer, K.; Gibb, E.

    2014-07-01

    Comets are true remnants of our primordial Solar System, and provide unique clues to its formation and evolution, including the delivery of organics and water to our planet. A key indicator stored in the molecular structure of the nuclear ices is the spin temperature (T_{spin}), derived from spin-isomeric ratios (R_{spin}, e.g., ortho/para). At the time when cometary ices formed, the prevailing temperature defined the relative abundance of the different spin-isomeric species, and herewith R_{spin} and T_{spin} are normally treated as ''remnant thermometers'' probing the formation environments of cometary molecules. Radiative and collisional transitions between the ortho and para states are strongly forbidden and herewith this indicator is preserved over time. Most of our knowledge of this indicator comes from the measurements of the ortho-para ratios in water and NH_2 (a proxy for ammonia), suggesting a common T_{spin} near 30 K. This information is based on a restricted sample of comets, and the measurements are particularly sensitive to the molecular modeling technique and adopted spectral database. Here, we present new methodologies for extracting spin temperatures from ethane (C_2H_6), methane (CH_4), and methanol (CH_3OH), and advanced new models for ortho/para water (H_2O) and ammonia (NH_3). Our H_2O analysis is based on the most complete fluorescence radiative-transfer model to date, which incorporates 1,200 million transitions including those originating from high-energy levels that are activated in comets via a non-resonant cascade. In a similar fashion, we developed non-resonant fluorescence models for NH_3 and HCN, and quantum-band models for the ν_7 band of C_2H_6 and ν_3 band of CH_3OH. All models respect spin-symmetry non-conversion radiative rules, and make use of a realistic solar spectrum for the computation of fluorescence pumps. We applied these new methods to derive spin-isomeric ratios for H_2O, CH_4, C_2H_6, CH_3OH, and NH_3 from three high

  16. Benchmark calculations on the nuclear quadrupole-coupling parameters for open-shell molecules using non-relativistic and scalar-relativistic coupled-cluster methods

    SciTech Connect

    Cheng, Lan

    2015-08-14

    Quantum-chemical computations of nuclear quadrupole-coupling parameters for 24 open-shell states of small molecules based on non-relativistic and spin-free exact two-component (SFX2C) relativistic equation-of-motion coupled-cluster (EOM-CC) as well as spin-orbital-based restricted open-shell Hartree-Fock coupled-cluster (ROHF-CC) methods are reported. Relativistic effects, the performance of the EOM-CC and ROHF-CC methods for treating electron correlation, as well as basis-set convergence have been carefully analyzed. Consideration of relativistic effects is necessary for accurate calculations on systems containing third-row (K-Kr) and heavier elements, as expected, and the SFX2C approach is shown to be a useful cost-effective option here. Further, it is demonstrated that the EOM-CC methods constitute flexible and accurate alternatives to the ROHF-CC methods in the calculations of nuclear quadrupole-coupling parameters for open-shell states.

  17. Empirical Investigation of Extreme Single-Particle Behavior of Nuclear Quadrupole Moments in Highly Collective A {approx} 150 Superdeformed Bands

    SciTech Connect

    Clark, S. T.; Hackman, G.; Janssens, R. V. F.; Clark, R. M.; Fallon, P.; Floor, S. N.; Lane, G. J.; Macchiavelli, A. O.; Norris, J.; Sanders, S. J.

    2001-10-22

    The intrinsic quadrupole moment Q{sub 0} of superdeformed rotational bands in A{approx}150 nuclei depends on the associated single-particle configuration. We have derived an empirical formula based on the additivity of effective quadrupole moments of single-particle orbitals that describes existing measurements from {sup 142}Sm to {sup 152}Dy . To further test the formula, the predicted Q{sub 0} moments for two superdeformed bands in {sup 146}Gd of 14.05 eb were confronted with a new measurement yielding 13.9{+-}0.4 eb and 13.9{+-}0.3 eb , respectively. This excellent agreement provides empirical evidence of extreme single-particle behavior in highly deformed, collective systems.

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

    SciTech Connect

    Minkov, N.; Yotov, P.; Drenska, S.; Scheid, W.; Bonatsos, Dennis; Lenis, D.; Petrellis, D.

    2006-04-26

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

  19. 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 Tmax˜20 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.

  20. Detection of an unconventional superconducting phase in the vicinity of the strong first-order magnetic transition in CrAs using (75)As-nuclear quadrupole resonance.

    PubMed

    Kotegawa, Hisashi; Nakahara, Shingo; Akamatsu, Rui; Tou, Hideki; Sugawara, Hitoshi; Harima, Hisatomo

    2015-03-20

    Pressure-induced superconductivity was recently discovered in the binary helimagnet CrAs. We report the results of measurements of nuclear quadrupole resonance for CrAs under pressure. In the vicinity of the critical pressure P(c) between the helimagnetic (HM) and paramagnetic (PM) phases, a phase separation is observed. The large internal field remaining in the phase-separated HM state indicates that the HM phase disappears through a strong first-order transition. This indicates the absence of a quantum critical point in CrAs; however, the nuclear spin-lattice relaxation rate 1/T(1) reveals that substantial magnetic fluctuations are present in the PM state. The absence of a coherence effect in 1/T(1) in the superconducting state provides evidence that CrAs is the first Cr-based unconventional superconductor. PMID:25839303

  1. Nqrs Data for C8H5Li2O4.5 [C8H4Li2O4·1/2(H2O)] (Subst. No. 1059)

    NASA Astrophysics Data System (ADS)

    Chihara, H.; Nakamura, N.

    This document is part of Subvolume A `Substances Containing Ag … C10H15' of Volume 48 `Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III `Condensed Matter'. It contains an extract of Section `3.2 Data tables' of the Chapter `3 Nuclear quadrupole resonance data' providing the NQRS data for C8H5Li2O4.5 [C8H4Li2O4·1/2(H2O)] (Subst. No. 1059)

  2. The Iodine Hvperfine Structure in the Microwave Spectrum of Ethyl Iodide: Nuclear Quadrupole and Spin Rotation Coupling

    NASA Astrophysics Data System (ADS)

    Lee, W. W.; Scherr, Lawrence M.; Barsh, Max K.

    1988-11-01

    Some rotational transitions of ethyl iodide, CH3CH2I, have been reinvestigated by microwave Fourier transform (MWFT) spectroscopy. The iodine hyperfine structure splittings were first ana lyzed using a direct diagonalization procedure of the complete quadrupole Hamiltonian matrix. The results of this analysis showed deviations from our measurements up to 60 kHz. A new analysis using additional spin rotation coupling matrix elements reproduces our measurements within the experi­mental error limit and decreases the standard deviation of the least squares fit from 28 kHz to only 4 kHz.

  3. Hyperfine and Nuclear Quadrupole Tensors of Nitrogen Donors in the QA Site of Bacterial Reaction Centers: Correlation of the Histidine Nδ Tensors with Hydrogen Bond Strength

    PubMed Central

    2015-01-01

    X- and Q-band pulsed EPR spectroscopy was applied to study the interaction of the QA site semiquinone (SQA) with nitrogens from the local protein environment in natural abundance 14N and in 15N uniformly labeled photosynthetic reaction centers of Rhodobacter sphaeroides. The hyperfine and nuclear quadrupole tensors for His-M219 Nδ and Ala-M260 peptide nitrogen (Np) were estimated through simultaneous simulation of the Q-band 15N Davies ENDOR, X- and Q-band 14,15N HYSCORE, and X-band 14N three-pulse ESEEM spectra, with support from DFT calculations. The hyperfine coupling constants were found to be a(14N) = 2.3 MHz, T = 0.3 MHz for His-M219 Nδ and a(14N) = 2.6 MHz, T = 0.3 MHz for Ala-M260 Np. Despite that His-M219 Nδ is established as the stronger of the two H-bond donors, Ala-M260 Np is found to have the larger value of a(14N). The nuclear quadrupole coupling constants were estimated as e2Qq/4h = 0.38 MHz, η = 0.97 and e2Qq/4h = 0.74 MHz, η = 0.59 for His-M219 Nδ and Ala-M260 Np, respectively. An analysis of the available data on nuclear quadrupole tensors for imidazole nitrogens found in semiquinone-binding proteins and copper complexes reveals these systems share similar electron occupancies of the protonated nitrogen orbitals. By applying the Townes–Dailey model, developed previously for copper complexes, to the semiquinones, we find the asymmetry parameter η to be a sensitive probe of the histidine Nδ–semiquinone hydrogen bond strength. This is supported by a strong correlation observed between η and the isotropic coupling constant a(14N) and is consistent with previous computational works and our own semiquinone-histidine model calculations. The empirical relationship presented here for a(14N) and η will provide an important structural characterization tool in future studies of semiquinone-binding proteins. PMID:25026433

  4. (14)N Nuclear Quadrupole Coupling and Methyl Internal Rotation in N-tert-Butylacetamide As Observed by Microwave Spectroscopy.

    PubMed

    Kannengießer, Raphaela; Stahl, Wolfgang; Nguyen, Ha Vinh Lam; Kleiner, Isabelle

    2016-06-16

    The rotational spectrum of N-tert-butylacetamide, CH3(C═O)(NH)C(CH3)3, was measured in the frequency range from 2 to 26.5 GHz using a molecular beam Fourier transform microwave spectrometer. Only one conformer with trans configuration and Cs symmetry was observed. Torsional splittings up to 4.3 GHz occurred in the spectrum due to the internal rotation of the acetyl methyl group CH3(C═O) with a barrier height of approximately 65 cm(-1). Hyperfine structures arise from the quadrupole coupling of the (14)N nucleus appeared for all rotation-torsional transitions. The data set was reproduced with the programs XIAM and BELGI-C1-hyperfine, an extended version of the BELGI-C1 code that includes the effect of the (14)N quadrupole coupling, to root-mean-square deviations of 16.9 and 3.0 kHz, respectively. Quantum chemical calculations were performed to complement the experimental results. The BELGI-C1-hyperfine code was also used to refit the recently published microwave data of N-ethylacetamide to measurement accuracy. PMID:27213507

  5. 2H nuclear magnetic resonance order parameter profiles suggest a change of molecular shape for phosphatidylcholines containing a polyunsaturated acyl chain.

    PubMed Central

    Holte, L. L.; Peter, S. A.; Sinnwell, T. M.; Gawrisch, K.

    1995-01-01

    Solid-state 2H nuclear magnetic resonance spectroscopy was used to determine the orientational order parameter profiles for a series of phosphatidylcholines with perdeuterated stearic acid, 18:0d35, in position sn-1 and 18:1 omega 9, 18:2 omega 6, 18:3 omega 3, 20:4 omega 6, 20:5 omega 3, or 22:6 omega 3 in position sn-2. The main phase transition temperatures were derived from a first moment analysis, and order parameter profiles of sn-1 chains were calculated from dePaked nuclear magnetic resonance powder patterns. Comparison of the profiles at 37 degrees C showed that unsaturation causes an inhomogenous disordering along the sn-1 chain. Increasing sn-2 chain unsaturation from one to six double bonds resulted in a 1.6-kHz decrease in quadrupolar splittings of the sn-1 chain in the upper half of the chain (or plateau region) and maximum splitting difference of 4.4 kHz at methylene carbon 14. The change in chain order corresponds to a decrease in the 18:0 chain length of 0.4 +/- 0.2 A with 18:2 omega 6 versus 18:1 omega 9 in position sn-2. Fatty acids containing three or more double bonds in sn-2 showed a decrease in sn-1 chain length of 0.7 +/- 0.2 A compared with 18:1 omega 9. The chain length of all lipids decreased with increasing temperature. Highly unsaturated phosphatidylcholines (three or more double bonds in sn-2) had shorter sn-1 chains, but the chain length was somewhat less sensitive to temperature. The profiles reveal that the sn-1 chain exhibits a selective increase in motional freedom in a region located toward the bottom half of the chain as sn-2 unsaturation is increased. This corresponds to an area increase around carbon atom number 14 that is three to four times greater than the increase for the top part of the chain. A similar asymmetric decrease in order, largest toward the methyl end of the chain, was observed when 1 -palmitoyl-2-oleoylphosphatidylethanolamine goes from a lamellar to an inverse hexagonal (H,,) phase. This is consistent with a

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

    NASA Astrophysics Data System (ADS)

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

    1990-08-01

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

  7. Evaluation of nitrogen nuclear hyperfine and quadrupole coupling parameters for the proximal imidazole in myoglobin-azide, -cyanide, and -mercaptoethanol complexes by electron spin echo envelope modulation spectroscopy.

    PubMed

    Magliozzo, R S; Peisach, J

    1993-08-24

    Electron spin echo envelope modulation (ESEEM) spectroscopy and computer simulation of spectra has been used to evaluate the nitrogen nuclear hyperfine and quadrupole coupling parameters for the proximal imidazole nitrogen directly coordinated to iron in three low-spin heme complexes, myoglobin-azide, -cyanide, and -mercaptoethanol (MbN3, MbCN, and MbRS). The variability in the weak electron-nuclear coupling parameters reveals the electronic flexibility within the heme group that depends on properties of the exogenous ligands. For example, the isotropic component of the nitrogen nuclear hyperfine coupling ranges from 4.4 MHz for MbN3 to 2.2 MHz for both MbCN and MbRS. The weaker coupling in MbCN and MbRS is taken as evidence for delocalization of unpaired electron spin from iron into the exogenous anionic ligands. The value of e2Qq, the nuclear quadrupole coupling constant for the axial imidazole nitrogen in MbCN and MbRS, was 2.5 MHz but was significantly larger, 3.2 MHz, in MbN3. This large value is considered evidence for a weakened sigma bond between the proximal imidazole and ferric iron in this form, and for a feature contributing to the origin of the high spin-low spin equilibrium exhibited by MbN3 [Beetlestone, J., & George, P. (1964) Biochemistry 5, 707-714]. The ESEEM results have allowed a correlation to be made between the orientation of the g tensor axes, the orientation of the p-pi orbital of the proximal imidazole nitrogen, and sigma- and pi-bonding features of the axial ligands. Furthermore, the proximal imidazole is suggested to act as a pi-acceptor in low-spin heme complexes in order to support strong sigma electron donation from the lone pair orbital to iron. An evaluation of the nitrogen nuclear hyperfine coupling parameters for the porphyrin pyrrole sites in MbRS reveals a large inequivalence in isotropic components consistent with an orientation of rhombic axes (and g tensor axes) that eclipses the Fe-Npyrrole vector directions. PMID:8395204

  8. Effective quadrupole-quadrupole interaction from density functional theory

    NASA Astrophysics Data System (ADS)

    Alhassid, Y.; Bertsch, G. F.; Fang, L.; Sabbey, B.

    2006-09-01

    The density functional theory of nuclear structure provides a many-particle wave function that is useful for static properties, but an extension of the theory is necessary to describe correlation effects or other dynamic properties. We propose a procedure to extend the theory by mapping the properties of a self-consistent mean-field theory onto an effective shell-model Hamiltonian with quadrupole-quadrupole interaction. In this initial study, we consider the sd-shell nuclei Ne20, Mg24, Si28, and Ar36. The method is first tested with the USD shell-model Hamiltonian, using its mean-field approximation to construct an effective Hamiltonian and partially recover correlation effects. We find that more than half of the correlation energy is due to the quadrupole interaction. We then follow a similar procedure but using the SLy4 Skyrme energy functional as our starting point and truncating the space to the spherical sd shell. The constructed shell-model Hamiltonian is found to satisfy minimal consistency requirements to reproduce the properties of the mean-field solution. The quadrupolar correlation energies computed with the mapped Hamiltonian are reasonable compared with those computed by other methods. The method also provides a well-defined renormalization of the quadrupole operator in the shell-model space, the “effective charge” of the phenomenological shell model.

  9. MICROWAVE SPECTRA AND GEOMETRIES OF C2H_{2\\cdots AgI} and C2H_{4\\cdots AgI}

    NASA Astrophysics Data System (ADS)

    Stephens, Susanna L.; Tew, David Peter; Walker, Nick; Legon, Anthony

    2015-06-01

    A chirped-pulse Fourier transform microwave spectrometer has been used to measure the microwave spectra of both C2H_{2\\cdots AgI} and C2H_{4\\cdots AgI}. These complexes are generated via laser ablation at 532 nm of a silver surface in the presence of CF3I and either C2H_{2} or C2H_{4} and argon and are stabilized by a supersonic expansion. Rotational (A0, B0, C0) and centrifugal distortion constants (ΔJ and ΔJK) of each molecule have been determined as well the nuclear electric quadrupole coupling constants the iodine atom (χaa(I) and χbb-χcc(I)). The spectrum of each molecule is consistent with a C2v structure in which the metal atom interacts with the π-orbital of the ethene or ethyne molecule. Isotopic substitutions of atoms within the C2H_{2} or C2H_{4} subunits are in progress and in conjunction with high level ab initio calculations will allow for accurate determination of the geometry of each molecule. These to complexes are put in the context of the recently studied H2S\\cdots AgI, OC\\cdotsAgI, H3N\\cdots AgI and (CH3)_{3N\\cdots AgI}. S.Z. Riaz, S.L. Stephens, W. Mizukami, D.P. Tew, N.R. Walker, A.C. Legon, Chem. Phys. Let., 531, 1-12 (2012) S.L. Stephens, W. Mizukami, D.P. Tew, N.R. Walker, A.C. Legon, J. Chem. Phys., 136(6), 064306 (2012) D.M. Bittner, D.P. Zaleski, S.L. Stephens, N.R. Walker, A.C. Legon, Study in progress.

  10. 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.

  11. Effect of Sterol Structure on the Physical Properties of 1-Palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine Membranes Determined Using (2)H Nuclear Magnetic Resonance.

    PubMed

    Shaghaghi, Mehran; Chen, Mei-Ting; Hsueh, Ya-Wei; Zuckermann, Martin J; Thewalt, Jenifer L

    2016-08-01

    The effect of a series of phytosterols on lipid chain ordering in 1-palmitoyl((2)H31)-2-oleoyl-sn-glycero-3-phosphocholine (POPC-d31) multibilayer vesicles was examined by (2)H NMR spectroscopy at 25 °C. These results, along with existing data for other sterols, indicate that the ordering power of sterols in POPC-d31 depends on subtle aspects of sterol structure. Cholesterol, 7-dehydrocholesterol (7-DHC), campesterol, β-sitosterol, ergosterol, brassicasterol, and stigmasterol all increase the lipid chain order as sterol concentration is increased. However, saturation of the ordering occurs at different sterol concentrations for ergosterol (as previously reported), brassicasterol, β-sitosterol, and stigmasterol. Here our interest lies in finding which part of the sterol structure is responsible for the observed saturation of the palmitoyl chain order as a function of sterol concentration. In particular, we propose that the saturation of the ordering of POPC-d31/brassicasterol and POPC-d31/stigmasterol membranes at quite low sterol concentrations is due to the presence of a double bond at C22. We also discuss how the structural differences between the sterols affect their ability to intercalate between the POPC acyl chains. Furthermore, the effective solubility of sterols in POPC is discussed in relation to the dependence of maximum POPC-d31 chain order vs sterol concentration. PMID:27341069

  12. Multiple Locations of Peptides in the Hydrocarbon Core of Gel-Phase Membranes Revealed by Peptide 13C to Lipid 2H Rotational-Echo Double-Resonance Solid-State Nuclear Magnetic Resonance

    PubMed Central

    2015-01-01

    Membrane locations of peptides and proteins are often critical to their functions. Solid-state rotational-echo double-resonance (REDOR) nuclear magnetic resonance is applied to probe the locations of two peptides via peptide 13CO to lipid 2H distance measurements. The peptides are KALP, an α-helical membrane-spanning peptide, and HFP, the β-sheet N-terminal fusion peptide of the HIV gp41 fusion protein that plays an important role in HIV–host cell membrane fusion. Both peptides are shown to have at least two distinct locations within the hydrocarbon core of gel-phase membranes. The multiple locations are attributed to snorkeling of lysine side chains for KALP and to the distribution of antiparallel β-sheet registries for HFP. The relative population of each location is also quantitated. To the best of our knowledge, this is the first clear experimental support of multiple peptide locations within the membrane hydrocarbon core. These data are for gel-phase membranes, but the approach should work for liquid-ordered membranes containing cholesterol and may be applicable to liquid-disordered membranes with appropriate additional analysis to take into account protein and lipid motion. This paper also describes the methodological development of 13CO–2H REDOR using the lyophilized I4 peptide that is α-helical and 13CO-labeled at A9 and 2Hα-labeled at A8. The I4 spins are well-approximated as an ensemble of isolated 13CO–2H spin pairs each separated by 5.0 Å with a 37 Hz dipolar coupling. A pulse sequence with rectangular 100 kHz 2H π pulses results in rapid and extensive buildup of REDOR (ΔS/S0) with a dephasing time (τ). The buildup is well-fit by a simple exponential function with a rate of 24 Hz and an extent close to 1. These parameter values reflect nonradiative transitions between the 2H spin states during the dephasing period. Each spin pair spends approximately two-thirds of its time in the 13CO–2H (m = ±1) states and approximately one-third of

  13. Evidence for Unconventional Strong-Coupling Superconductivity in PrOs4Sb12: An Sb Nuclear Quadrupole Resonance Study

    NASA Astrophysics Data System (ADS)

    Kotegawa, H.; Yogi, M.; Imamura, Y.; Kawasaki, Y.; Zheng, G.-Q.; Kitaoka, Y.; Ohsaki, S.; Sugawara, H.; Aoki, Y.; Sato, H.

    2003-01-01

    We report Sb-NQR results which evidence a heavy-fermion (HF) behavior and an unconventional superconducting (SC) property in Pr(Os4Sb12 with Tc=1.85 K. The temperature (T) dependence of nuclear-spin-lattice-relaxation rate, 1/T1, and NQR frequency unravel a low-lying crystal-electric-field splitting below T0˜10 K, associated with Pr3+(4f2)-derived ground state. In the SC state, 1/T1 shows neither a coherence peak just below Tc K nor a T3-like power-law behavior observed for anisotropic HF superconductors with the line-node gap. The isotropic energy gap with its size Δ/kB=4.8 K seems to open up across Tc below T*˜2.3 K. It is surprising that Pr(Os4Sb12 looks like an isotropic HF superconductor—it may indeed argue for Cooper pairing via quadrupolar fluctuations.

  14. Rotational spectra and nitrogen nuclear quadrupole coupling for the cyanoacetylene dimer: Hsbnd Ctbnd Csbnd Ctbnd N⋯Hsbnd Ctbnd Csbnd Ctbnd N

    NASA Astrophysics Data System (ADS)

    Kang, Lu; Davis, Philip; Dorell, Ian; Li, Kexin; Daly, Adam; Novick, Stewart E.; Kukolich, Stephen G.

    2016-03-01

    The rotational spectra of cyanoacetylene dimer, Hsbnd Ctbnd Csbnd Ctbnd N⋯Hsbnd Ctbnd Csbnd Ctbnd N, were recorded using Balle-Flygare type Fourier transform microwave (FTMW) spectrometers. The low J transitions were measured down to 1.3 GHz at very high resolution, FWHM ∼ 1 kHz. The spectral hyperfine structure due to the 14N nuclear quadrupole coupling interactions is well-resolved below 4 GHz using a low frequency spectrometer at the University of Arizona. The experimental spectroscopic constants were fitted as: B0 = 339.2923310(79) MHz, DJ = 32.152(82) Hz, H = -0.00147(20) Hz, eqQ(14N1) = -3.9902(14) MHz, and eqQ(14N2) = -4.1712(13) MHz. The vibrationally averaged dimer configuration is Hsbnd Ctbnd Csbnd Ctbnd N⋯Hsbnd Ctbnd Csbnd Ctbnd N. Using a simple linear model, the vibrational ground state and the equilibrium hydrogen bond lengths are determined to be: r0(N⋯H) = 2.2489(3) Å and re(N⋯H) = 2.2315 Å. The equilibrium center-of-mass distance between the two HCCCN subunits is rcom = 7.0366 Å. Using the rigid precession model, the vibrational ground state center-of-mass distance and the pivot angles which HCCCN subunits make with the a-axis of Hsbnd Ctbnd Csbnd Ctbnd N⋯Hsbnd Ctbnd Csbnd Ctbnd N are rc.m. = 7.0603 Å, θ1 = 13.0°, and θ2 = 8.7°, respectively. The calculated hydrogen bond energy of Hsbnd Ctbnd Csbnd Ctbnd N⋯Hsbnd Ctbnd Csbnd Ctbnd N is 1466 cm-1 using the MP2/aug-cc-PVTZ method in present work.

  15. Measurements of the microwave spectrum, Re-H bond length, and Re quadrupole coupling for HRe(CO)5

    NASA Astrophysics Data System (ADS)

    Kukolich, Stephen G.; Sickafoose, Shane M.

    1993-11-01

    Rotational transition frequencies for rhenium pentacarbonyl hydride were measured in the 4-10 GHz range using a Flygare-Balle type microwave spectrometer. The rotational constants and Re nuclear quadrupole coupling constants for the four isotopomers, (1) H187Re(CO)5, (2) H185Re(CO)5, (3) D187Re(CO)5, and (4) D185Re(CO)5, were obtained from the spectra. For the most common isotopomer, B(1)=818.5464(2) MHz and eq Q(187Re)=-900.13(3) MHz. The Re-H bond length (r0) determined by fitting the rotational constants is 1.80(1) Å. Although the Re atom is located at a site of near-octahedral symmetry, the quadrupole coupling is large due to the large Re nuclear moments. A 2.7% increase in Re quadrupole coupling was observed for D-substituted isotopomers, giving a rather large isotope effect on the quadrupole coupling. The Cax-Re-Ceq angle is 96(1)°, when all Re-C-O angles are constrained to 180°.

  16. Nuclear localization of the C2H2 zinc finger protein Msn2p is regulated by stress and protein kinase A activity.

    PubMed

    Görner, W; Durchschlag, E; Martinez-Pastor, M T; Estruch, F; Ammerer, G; Hamilton, B; Ruis, H; Schüller, C

    1998-02-15

    Msn2p and the partially redundant factor Msn4p are key regulators of stress-responsive gene expression in Saccharomyces cerevisiae. They are required for the transcription of a number of genes coding for proteins with stress-protective functions. Both Msn2p and Msn4p are Cys2His2 zinc finger proteins and bind to the stress response element (STRE). In vivo footprinting studies show that the occupation of STREs is enhanced in stressed cells and dependent on the presence of Msn2p and Msn4p. Both factors accumulate in the nucleus under stress conditions, such as heat shock, osmotic stress, carbon-source starvation, and in the presence of ethanol or sorbate. Stress-induced nuclear localization was found to be rapid, reversible, and independent of protein synthesis. Nuclear localization of Msn2p and Msn4p was shown to be correlated inversely to cAMP levels and protein kinase A (PKA) activity. A region with significant homologies shared between Msn2p and Msn4p is sufficient to confer stress-regulated localization to a SV40-NLS-GFP fusion protein. Serine to alanine or aspartate substitutions in a conserved PKA consensus site abolished cAMP-driven nuclear export and cytoplasmic localization in unstressed cells. We propose stress and cAMP-regulated intracellular localization of Msn2p to be a key step in STRE-dependent transcription and in the general stress response. PMID:9472026

  17. Superconducting magnetic quadrupole

    SciTech Connect

    Kim, J.W.; Shepard, K.W.; Nolen, J.A.

    1995-08-01

    A design was developed for a 350 T/m, 2.6-cm clear aperture superconducting quadrupole focussing element for use in a very low q/m superconducting linac as discussed below. The quadrupole incorporates holmium pole tips, and a rectangular-section winding using standard commercially-available Nb-Ti wire. The magnet was modeled numerically using both 2D and 3D codes, as a basis for numerical ray tracing using the quadrupole as a linac element. Components for a prototype singlet are being procured during FY 1995.

  18. 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

  19. Theoretical Study of the Electrostatic and Steric Effects on the Spectroscopic Characteristics of the Metal-Ligand Unit of Heme Proteins. 2. C-O Vibrational Frequencies, 17O Isotropic Chemical Shifts, and Nuclear Quadrupole Coupling Constants

    PubMed Central

    Kushkuley, Boris; Stavrov, Solomon S.

    1997-01-01

    The quantum chemical calculations, vibronic theory of activation, and London-Pople approach are used to study the dependence of the C-O vibrational frequency, 17O isotropic chemical shift, and nuclear quadrupole coupling constant on the distortion of the porphyrin ring and geometry of the CO coordination, changes in the iron-carbon and iron-imidazole distances, magnitude of the iron displacement out of the porphyrin plane, and presence of the charged groups in the heme environment. It is shown that only the electrostatic interactions can cause the variation of all these parameters experimentally observed in different heme proteins, and the heme distortions could modulate this variation. The correlations between the theoretically calculated parameters are shown to be close to the experimentally observed ones. The study of the effect of the electric field of the distal histidine shows that the presence of the four C-O vibrational bands in the infrared absorption spectra of the carbon monoxide complexes of different myoglobins and hemoglobins can be caused by the different orientations of the different tautomeric forms of the distal histidine. The dependence of the 17O isotropic chemical shift and nuclear quadrupole coupling constant on pH and the distal histidine substitution can be also explained from the same point of view. PMID:9017215

  20. High gradient superconducting quadrupoles

    SciTech Connect

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

    1987-07-01

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

  1. p-p minimum-bias dijets and nonjet quadrupole in relation to conjectured collectivity (flows) in high-energy nuclear collisions

    NASA Astrophysics Data System (ADS)

    Trainor, Thomas A.

    2016-07-01

    Recent observations of ridge-like structure in p-p and p-A angular correlations at the RHIC and LHC have been interpreted to imply collective motion in smaller collision systems. It is argued that if correlation structures accepted as manifestations of flow in A-A collisions appear in smaller systems collectivity (flow) must extend to the smaller systems. But the argument could be reversed to conclude that such structures appearing in A-A collisions may not imply hydrodynamic flow. I present spectrum, correlation and fluctuation data from RHIC p-p and Au-Au collisions and p-p, p-Pb and Pb-Pb results from the LHC described accurately by a two-component (soft+dijet) model of hadron production. I also present evidence for a significant p-p nonjet (NJ) quadrupole (v2) component with nch systematics directly related to A-A NJ quadrupole systematics. The combination suggests that soft, dijet and NJ quadrupole com- ponents are distinct phenomena in all cases, inconsistent with hadron production from a common bulk medium exhibiting collective motion (flow).

  2. Isolation of a Novel Family of C2H2 Zinc Finger Proteins Implicated in Transcriptional Repression Mediated by Chicken Ovalbumin Upstream Promoter Transcription Factor (COUP-TF) Orphan Nuclear Receptors*

    PubMed Central

    Avram, Dorina; Fields, Andrew; Top, Karen Pretty On; Nevrivy, Daniel J.; Ishmael, Jane E.; Leid, Mark

    2010-01-01

    Two novel and related C2H2 zinc finger proteins that are highly expressed in the brain, CTIP1 and CTIP2 (COUP TF-interacting proteins 1 and 2, respectively), were isolated and shown to interact with all members of the chicken ovalbumin upstream promoter transcription factor (COUP-TF) subfamily of orphan nuclear receptors. The interaction of CTIP1 with ARP1 was studied in detail, and CTIP1 was found to harbor two independent ARP1 interaction domains, ID1 and ID2, whereas the putative AF-2 of ARP1 was required for interaction with CTIP1. CTIP1, which exhibited a punctate staining pattern within the nucleus of transfected cells, recruited cotransfected ARP1 to these foci and potentiated ARP1-mediated transcriptional repression of a reporter construct. However, transcriptional repression mediated by ARP1 acting through CTIP1 did not appear to involve recruitment of a trichostatin A-sensitive histone deacetylase(s) to the template, suggesting that this repression pathway may be distinct from that utilized by several other nuclear receptors. PMID:10744719

  3. Adiabatic hyperspherical study of weakly bound He(2)H(-), He(2)H, and HeH(2) systems.

    PubMed

    Suno, Hiroya

    2010-06-14

    The He(2)H(-), He(2)H, and HeH(2) triatomic systems are studied using the adiabatic hyperspherical representation. By adopting the best empirical interaction potentials, we search for weakly bound states of (4)He(2) H(-), (4)He(2) H, and (4)HeH(2). We consider not only zero total nuclear orbital angular momentum, J=0, states but also J>0 states. We find no bound state for the (4)He(2) H systems, while the (4)He(2) H(-) and (4)HeH(2) systems are shown to possess three and one bound states, respectively, for J(Pi)=0(+). Interestingly, one bound state has been found each for the J(Pi)=1(-) and 2(+) symmetries of the (4)He(2) H(-) anion. We shall calculate the bound state energies and analyze the molecular structure of these species in detail. PMID:20550401

  4. The Quadrupole Mass Spectrometer

    ERIC Educational Resources Information Center

    Matheson, E.; Harris, T. J.

    1969-01-01

    Describes the construction and operation of a quadrupole mass spectrometer for experiments in an advanced-teaching laboratory. Discusses the theory of operation of the spectrometer and the factors affecting the resolution. Some examples of mass spectra obtained with this instrument are presented and discussed. (LC)

  5. Dissociative attachment of electrons with Si2H6

    NASA Technical Reports Server (NTRS)

    Krishnakumar, E.; Srivastava, S. K.; Iga, I.

    1991-01-01

    Cross-sections for the production of negative ion fragments by electron attachment to Si2H6 and ion pair formation from it have been measured by utilizing the crossed electron beam-molecular beam collision technique. The negative ions are mass-analyzed by employing a quadrupole mass spectrometer. There are serious disagreements between the present and two previously published results. In the present paper cross-section values, appearance potentials, and the various channels of dissociation for the formation of negative monosilane fragments are presented.

  6. Short hydrogen bonds in salts of dicarboxylic acids; structural correlations from solid-state 13C and 2H NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Kalsbeek, Nicoline; Schaumburg, Kjeld; Larsen, Sine

    1993-10-01

    Solid-state 13C and 2H NMR spectra are found to very suitable for characterizing the short Osbnd H...O hydrogen bonds observed in acid salts of dicarboxylic acids. The majority of the investigated compounds are acid salts of malonic, succinic and tartaric acid with monovalent cations derived from alkali metals and small aliphatic amines. They include systems with symmetric and asymmetric hydrogen bonds. Accurate structural information about their geometry is available from low-temperature X-ray diffraction data. The 13C chemical shifts of the C atoms in the different carboxy groups display a linear variation with the absolute difference between the two Csbnd O bond lengths. Theoretical ab initio calculations for model systems showed that the nuclear quadrupole coupling constant NQCC for 2H increases with increasing asymmetry of the hydrogen-bonded system. NQCC values for 2H in the short symmetric hydrogen-bonded systems are in the range 53-59 kHz compared with the larger values of up to 166kHz found in systems with longer asymmetric hydrogen bonds. The 2H NQCC values display a perfect linear dependence on the asymmetry of the hydrogen bond. 2H NQCC decreases with decreasing temperature in the symmetric hydrogen bonds showing that the corresponding potential has a single well.

  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. sup 17 O, sup 1 H, and sup 2 H electron nuclear double resonance characterization of solvent, substrate, and inhibitor binding to the (4Fe-4S) sup + cluster of aconitase

    SciTech Connect

    Werst, M.M.; Hoffman, B.M. ); Kennedy, M.C.; Beinert, H. )

    1990-11-01

    {sup 17}O electron nuclear double resonance (ENDOR) studies at X-band (9-GHz) and Q-band (35-GHz) microwave frequencies reveal that the (4Fe-4S){sup {plus}} cluster of substrate-free aconitase (citrate (isocitrate) hydro-lyase, EC 4.2.1.3) binds solvent, H{sub x}O (x = 1,2). Previous {sup 17}O ENDOR studies had disclosed that H{sub x}{sup 17}O binds to the enzyme-substrate complex and also to complexes of enzyme with the substrate analogues trans-aconitate and nitroisocitrate (1-hydroxy-2-nitro-1,3-propanedicarboxylate). The authors have used {sup 1}H and {sup 2}H ENDOR to characterize these solvent species. The authors propose that the fourth ligand of Fe{sub a} in substrate-free enzyme is a hydroxyl ion from the solvent; upon binding of substrate or substrate analogues at this Fe{sub a} site, the solvent species becomes protonated to form a water molecule. Previous {sup 17}O and {sup 13}C ENDOR studies showed that only a single carboxyl, at C-2 of the propane backbone of cis-aconitate or at C-1 of the inhibitor nitroisocitrate, coordinates to the cluster. Together, these results imply that enzyme-catalyzed interconversion of citrate and isocitrate does not involve displacement of an endogenous fourth ligand, but rather addition of the anionic carboxylate ligand and a change in protonation state of a solvent species bound to Fe{sub a}. The authors further report the {sup 17}O hyperfine tensor parameters of the C-2 carboxyl oxygen of substrate bound to the cluster as determined by the field dependence of the {sup 17}O ENDOR signals. {sup 17}O ENDOR studies also show that the carboxyl group of the inhibitor trans-aconitate binds similarly to that off substrate.

  9. Quadrupole Collectivity in Neutron Deficient Sn Isotopes

    NASA Astrophysics Data System (ADS)

    Gade, Alexandra

    2014-03-01

    One of the overarching goals of nuclear physics is the development of a comprehensive model of the atomic nucleus with predictive power across the nuclear chart. Of particular importance for the development of nuclear models is experimental data that consistently track the effect of isospin and changed binding, for example. The chain of Sn isotopes has been a formidable testing ground for nuclear models as some spectroscopic data is available from N = Z = 50 100Sn in the proximity of the proton dripline to 134Sn, beyond the very neutron-rich doubly magic nucleus 132Sn. In even-even nuclei, the electromagnetic quadrupole excitation strength is a measure of quadrupole collectivity, sensitive to the presence of shell gaps, nuclear deformation, and nucleon-nucleon correlations, for example. In the Sn isotopes, this transition strength has been reported from 104Sn to 130Sn, spanning a chain of 14 even-even Sn isotopes. The trend is asymmetric with respect to midshell and not even the largest-scale shell-model calculations have been able to describe the evolution of transition strength across the isotopic chain without varying effective charges. Implications will be discussed. This work was supported by the National Science Foundation under Grant No. PHY-1102511.

  10. Transport in rectangular quadrupole channels

    SciTech Connect

    Meier, E.

    1983-08-01

    Multiple electrostatic quadrupole arrays can be produced in many different geometries. However, the fabrication process can be considerably simplified if the poles are rectangular. This is especially true for millimeter sized channels. This paper presents the results of a series of measurements comparing the space charge limits in cylindrical and rectangular quadrupole channels.

  11. The halogen bond between ethene and a simple perfluoroiodoalkane: C2H4\\ctdot ICF3 identified by broadband rotational spectroscopy

    NASA Astrophysics Data System (ADS)

    Stephens, Susanna L.; Mizukami, Wataru; Tew, David P.; Walker, Nicholas R.; Legon, Anthony C.

    2012-10-01

    An isolated complex of C2H4 and ICF3 has been generated in the gas phase and studied by chirped-pulse, Fourier transform microwave (CP-FTMW) spectroscopy. Ab initio calculations at the CCSD(T)(F12*)/VTZ level support the experimental work and further establish the dissociation energy, De, and dipole moment, μ, of the complex. Rotational constants, B0 and C0, the centrifugal distortion constant, ΔJ, nuclear quadrupole coupling constants, χaa (I) and (χbb(I)-χcc(I)) and the nuclear spin-rotation coupling constant Cbb(I) of the complex are determined from the experimental data. The iodine atom interacts with π-electrons on C2H4 resulting in the formation of a linear (∠(Csbnd I⋯*)) halogen bond (where * indicates the centre of the Cdbnd C bond) and a complex of Cs symmetry. The measured rotational constants allow the length of the halogen bond to be determined as 3.434(2) Å in the r0 geometry. The complex is formally an asymmetric top but with a very low barrier to internal rotation of C2H4 about the C3 axis defined by the CF3I sub-unit. Adopting an approach also used in a recent study of H2O⋯ICF3, other transitions are assigned using the Hamiltonian of a symmetric top molecule.

  12. A prototype transition-metal olefin complex C2H4⋯AgCl synthesised by laser ablation and characterised by rotational spectroscopy and ab initio methods

    NASA Astrophysics Data System (ADS)

    Stephens, Susanna L.; Tew, David P.; Mikhailov, Victor A.; Walker, Nicholas R.; Legon, Anthony C.

    2011-07-01

    C2H4⋯Ag-Cl has been synthesised in the gas phase in a pulsed-jet, Fourier-transform microwave spectrometer by the reaction of laser-ablated metallic silver with carbon tetrachloride to give AgCl, which subsequently reacts with ethene to give the complex. The ground-state rotational spectra of six isotopologues (C2H4⋯107Ag35Cl, C2H4⋯109Ag35Cl, C2H4⋯107Ag37Cl, C2H4⋯109Ag37Cl, 13C2H4⋯107Ag35Cl, and 13C2H4⋯109Ag35Cl) were recorded and analysed to give rotational constants A0, B0, and C0, centrifugal distortion constants ΔJ and ΔJK, and Cl nuclear quadrupole coupling constants χaa(Cl) and χbb(Cl) - χcc(Cl). These spectroscopic constants were interpreted in terms of a geometry for C2H4⋯Ag-Cl of C2V symmetry in which the AgCl molecule lies along the C2 axis of ethene that is perpendicular to the C2H4 plane. The Ag atom forms a bond to the midpoint (*) of the ethene π bond. A partial rs-geometry and a r0-geometry were determined, with the values r(*⋯Ag) = 2.1719(9) Å, r(C-C) = 1.3518(4) Å, and r(Ag-Cl) = 2.2724(8) Å obtained in the latter case. The C-C bond lengthens on formation of the complex. Detailed ab initio calculations carried out at the CCSD(T)/cc-pVQZ level of theory give results in good agreement with experiment and also reveal that the ethene molecule undergoes a small angular distortion. The distortion is such that the four H atoms move in a direction away from Ag but remain coplanar. The two C atoms are no longer contained in this plane, however. The electric charge redistribution when C2H4⋯Ag-Cl is formed and the strength of the π⋯Ag bond are discussed.

  13. Electron Impact Ionization and Dissociative Ionization of C2H2

    NASA Technical Reports Server (NTRS)

    Srivastava, S. K.

    1995-01-01

    By utilizing a crossed electron beam collision geometry, a combination of time-of-flight (TOF) and quadrupole mass spectrometers, and the relative flow technique1 normalized values of cross sections and appearance energies (AP) were obtained for the formation of singly and multiply ionized species resulting from the ionization and dissociation of C2H2. Details ont he apparatus and technique have been published previously.2,3.

  14. Sodium-23 and potassium-39 nuclear magnetic resonance relaxation in eye lens. Examples of quadrupole ion magnetic relaxation in a crowded protein environment.

    PubMed Central

    Stevens, A; Paschalis, P; Schleich, T

    1992-01-01

    Single and multiple quantum nuclear magnetic resonance (NMR) spectroscopic techniques were used to investigate the motional dynamics of sodium and potassium ions in concentrated protein solution, represented in this study by cortical and nuclear bovine lens tissue homogenates. Both ions displayed homogeneous biexponential magnetic relaxation behavior. Furthermore, the NMR relaxation behavior of these ions in lens homogenates was consistent either with a model that assumed the occurrence of two predominant ionic populations, "free" and "bound," in fast exchange with each other or with a model that assumed an asymmetric Gaussian distribution of correlation times. Regardless of the model employed, both ions were found to occur in a predominantly "free" or "unbound" rapidly reorienting state. The fraction of "bound" 23Na+, assuming a discrete two-site model, was approximately 0.006 and 0.017 for cortical and nuclear homogenates, respectively. Corresponding values for 39K+ were 0.003 and 0.007, respectively. Estimated values for the fraction of "bound" 23Na+ or 39K+ obtained from the distribution model (tau C greater than omega L-1) were less than or equal to 0.05 for all cases examined. The correlation times of the "bound" ions, derived using either a two-site or distribution model, yielded values that were at least one order of magnitude smaller than the reorientational motion of the constituent lens proteins. This observation implies that the apparent correlation time for ion binding is dominated by processes other than protein reorientational motion, most likely fast exchange between "free" and "bound" environments. The results of NMR visibility studies were consistent with the above findings, in agreement with other studies performed by non-NMR methods. These studies, in combination with those presented in the literature, suggest that the most likely role for sodium and potassium ions in the lens appears to be the regulation of cell volume by affecting the

  15. Quadrupole Induced Resonant Particle Transport

    NASA Astrophysics Data System (ADS)

    Gilson, Erik; Fajans, Joel

    1999-11-01

    We have performed experiments that explore the effects of a magnetic quadrupole field on a pure electron plasma confined in a Malmberg-Penning trap. A model that we have developed describes the shape of the plasma and shows that a certain class of resonant particles follows trajectories that take them out of the plasma. Even though the quadrupole field destroys the cylindrical symmetry of the system, our theory predicts that if the electrons are off resonance, then the lifetime of the plasma will not be greatly affected by the quadrupole field. Our preliminary experimental results show that the shape of the plasma and the plasma lifetime agree with our model. We are investigating the scaling of this behavior with various experimental parameters such as the plasma length, density, and strength of the quadrupole field. In addition to being an example of resonant particle transport, this effect may find practical applications in experiments that plan to use magnetic quadrupole neutral atom traps to confine anti-hydrogen created in double-well positron/anti-proton Malmberg-Penning traps. (ATHENA Collaboration.)

  16. Quadrupole Induced Resonant Particle Transport

    NASA Astrophysics Data System (ADS)

    Gilson, Erik; Fajans, Joel

    1998-11-01

    We have performed experiments that explore the effects of a magnetic quadrupole field on a pure electron plasma confined in a Penning-Malmberg trap. A model that we have developed describes the shape of the plasma and shows that a certain class of resonant particles follows trajectories that take them out of the plasma. Even though the quadrupole field destroys the cylindrical symmetry of the system, our theory predicts that if the electrons are off resonance, then the lifetime of the plasma will not be greatly affected by the quadrupole field. Our preliminary experimental results show that the shape of the plasma and the plasma lifetime agree with our model. We are investigating the scaling of this behavior with various experimental parameters such as the plasma length, density, and strength of the quadrupole field. In addition to being an example of resonant particle transport, this effect may find practical applications in experiments that plan to use magnetic quadrupole neutral atom traps to confine anti-hydrogen created in double-well positron/anti-proton Penning-Malmberg traps. (ATHENA Collaboration.)

  17. 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.

  18. 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 Mössbauer spectra of ferrates(VI) was studied. The reasonable correlation between calculated and experimental splittings was observed for the majority of ferrates excepting K3Na(FeO4)2. The comparison of ferrates and chromates was made using calculated nucleus independent coefficient.

  19. 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.

  20. LCLS Undulator Quadrupole Fiducialization Plan

    SciTech Connect

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

    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.

  1. 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.

  2. Analytic formula for quadrupole-quadrupole matrix elements

    NASA Astrophysics Data System (ADS)

    Rosensteel, G.

    1990-12-01

    An analytic formula is reported for general matrix elements of the microscopic quadrupole-quadrupole operator in the U(3)-boson approximation. The complete infinite-dimensional basis of A-fermion wave functions is compatible with the harmonic-oscillator shell model and consists of np-nh configurations, with spurious center-of-mass excitations removed, which are symmetry adapted to the Elliott U(3) and symplectic Sp(3,R) models. The formula expresses the general Q2.Q2 matrix element with respect to this complete orthonormal basis as a Racah SU(3) U coefficient times a closed-shell matrix element. An oscillator closed-shell matrix element of Q2.Q2 is a square root of a rational function of the integer quantum numbers of the U(3) basis.

  3. Structure and properties of the (HCl)2H2O cluster observed by chirped-pulse Fourier transform microwave spectroscopy.

    PubMed

    Kisiel, Zbigniew; Lesarri, Alberto; Neill, Justin L; Muckle, Matt T; Pate, Brooks H

    2011-08-21

    The rotational spectrum of the cyclic (HCl)(2)H(2)O cluster has been identified for the first time in the chirped pulse, Fourier transform microwave spectrum of a supersonically expanded HCl/H(2)O/Ar mixture. The spectrum was measured at frequencies 6-18.5 GHz, and transitions in two inversion-tunneling states, at close to 1 : 3 relative intensity, have been assigned for the parent species. The two single (37)Cl isotopic species, and the double (37)Cl species have been assigned in the natural abundance sample, and the (18)O and HDO species of the cluster were identified in isotopically enriched samples. The rich nuclear quadrupole hyperfine structure due to the presence of two chlorine nuclei has been satisfactorily fitted and provided useful information on the nonlinearity of intermolecular bonds in the cluster. The r(s) heavy atom geometry of the cluster was determined and the strongest bond in the intermolecular cycle r(O···HCl) = 3.126(3) Å, is found to be intermediate in length between the values in H(2)O···HCl and (H(2)O)(2)HCl. The fitted spectroscopic constants and derived molecular properties are compared with ab initio predictions, and a discussion of complexation effects in these three clusters is made. PMID:21743896

  4. Extreme quadrupole deformation and clusterization

    NASA Astrophysics Data System (ADS)

    Darai, J.; Cseh, J.; Adamian, G.; Antonenko, N.

    2012-12-01

    We discuss a simple symmetry-adapted method for the determination of the shape isomers, and for the study of their possible fragmentation. In other words the connection between the quadrupole (collective) and dipole (cluster) degrees of freedom is considered in terms of an easily applicable, yet microscopic method. The energetics is taken into account by the double-folding method. Special attention is focused on those cases in which the theoretical predictions have a direct comparison with experimental observation.

  5. 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.

  6. Study and validity of 13C stable carbon isotopic ratio analysis by mass spectrometry and 2H site-specific natural isotopic fractionation by nuclear magnetic resonance isotopic measurements to characterize and control the authenticity of honey.

    PubMed

    Cotte, J F; Casabianca, H; Lhéritier, J; Perrucchietti, C; Sanglar, C; Waton, H; Grenier-Loustalot, M F

    2007-01-16

    Honey samples were analyzed by stable carbon isotopic ratio analysis by mass spectrometry (SCIRA-MS) and site-specific natural isotopic fractionation measured by nuclear magnetic resonance (SNIF-NMR) to first determine their potentials for characterizing the substance and then to combat adulteration. Honey samples from several geographic and botanical origins were analyzed. The delta(13)C parameter was not significant for characterizing an origin, while the (D/H)(I) ratio could be used to differentiate certain single-flower varieties. Application of the official control method of adding a C(4) syrup (AOAC official method 998.12) to our authentic samples revealed anomalies resulting from SCIRA indices that were more negative than -1 per thousand (permil). A filtration step was added to the experimental procedure and provided results that were compliant with the natural origin of our honey samples. In addition, spiking with a C(4) syrup could be detected starting at 9-10%. The use of SNIF-NMR is limited by the detection of a syrup spike starting only at 20%, which is far from satisfying. PMID:17386484

  7. 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.

  8. Quadrupole scattering in PrAl2

    NASA Astrophysics Data System (ADS)

    Sablik, M. J.; Pureur, P.; Creuzet, G.; Fert, A.; Levy, P. M.

    1983-10-01

    We derive the spontaneous anisotropy of the resistivity of the ferromagnetic compound PrAl2 from magnetoresistance measurements on a single crystal of PrAl2. We ascribe this spontaneous anisotropy of the resistivity to scattering of the conduction electrons by the thermal quadrupole disorder and we account for our experimental results by using the theoretical model previously developed by us. We find that quadrupole scattering gives a very important contribution to the total magnetic disorder (spin and quadrupole) resistivity but that only a small part of this quadrupole contribution is anisotropic.

  9. 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.

  10. Site-resolved 2H relaxation experiments in solid materials by global line-shape analysis of MAS NMR spectra

    NASA Astrophysics Data System (ADS)

    Lindh, E. L.; Stilbs, P.; Furó, I.

    2016-07-01

    We investigate a way one can achieve good spectral resolution in 2H MAS NMR experiments. The goal is to be able to distinguish between and study sites in various deuterated materials with small chemical shift dispersion. We show that the 2H MAS NMR spectra recorded during a spin-relaxation experiment are amenable to spectral decomposition because of the different evolution of spectral components during the relaxation delay. We verify that the results are robust by global least-square fitting of the spectral series both under the assumption of specific line shapes and without such assumptions (COmponent-REsolved spectroscopy, CORE). In addition, we investigate the reliability of the developed protocol by analyzing spectra simulated with different combinations of spectral parameters. The performance is demonstrated in a model material of deuterated poly(methacrylic acid) that contains two 2H spin populations with similar chemical shifts but different quadrupole splittings. In 2H-exchanged cellulose containing two 2H spin populations with very similar chemical shifts and quadrupole splittings, the method provides new site-selective information about the molecular dynamics.

  11. Site-resolved (2)H relaxation experiments in solid materials by global line-shape analysis of MAS NMR spectra.

    PubMed

    Lindh, E L; Stilbs, P; Furó, I

    2016-07-01

    We investigate a way one can achieve good spectral resolution in (2)H MAS NMR experiments. The goal is to be able to distinguish between and study sites in various deuterated materials with small chemical shift dispersion. We show that the (2)H MAS NMR spectra recorded during a spin-relaxation experiment are amenable to spectral decomposition because of the different evolution of spectral components during the relaxation delay. We verify that the results are robust by global least-square fitting of the spectral series both under the assumption of specific line shapes and without such assumptions (COmponent-REsolved spectroscopy, CORE). In addition, we investigate the reliability of the developed protocol by analyzing spectra simulated with different combinations of spectral parameters. The performance is demonstrated in a model material of deuterated poly(methacrylic acid) that contains two (2)H spin populations with similar chemical shifts but different quadrupole splittings. In (2)H-exchanged cellulose containing two (2)H spin populations with very similar chemical shifts and quadrupole splittings, the method provides new site-selective information about the molecular dynamics. PMID:27152833

  12. 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

  13. Hydrostatic pressure-induced conformational changes in phosphatidylcholine headgroups: a 2H NMR study.

    PubMed Central

    Bonev, B B; Morrow, M R

    1995-01-01

    The effects of pressure and temperature on 1,2-dipalmitoyl-sn-glycero-3-phosphocholine and 1,2-dimyristoyl-sn-glycero-3-phosphocholine headgroup conformations were examined using deuterium nuclear magnetic resonance. Isothermal compression was found to produce a decrease in the choline alpha deuteron quadrupole splitting and increases in the choline beta and gamma deuteron quadrupole splittings. A similar counterdirectional change, seen in the presence of positive surface charge, has been attributed to tilting of the headgroup away from the bilayer surface in response to the torque exerted on the phosphocholine dipole by positive surface charges. The direction of the change in headgroup deuteron quadrupole splitting is consistent with the pressure-induced reduction in area per lipid in the liquid crystalline phase, which can be inferred from the ordering of phospholipid acyl chains under comparable conditions. The temperature dependences of the headgroup deuteron quadrupole splittings were also examined. It was found that at elevated pressure, the alpha splitting was insensitive to temperature, whereas the beta and gamma splittings decreased. The response of the beta deuteron splitting to temperature was found to be weaker at elevated pressure than at ambient pressure. PMID:8527666

  14. Hydrostatic pressure-induced conformational changes in phosphatidylcholine headgroups: a 2H NMR study.

    PubMed

    Bonev, B B; Morrow, M R

    1995-08-01

    The effects of pressure and temperature on 1,2-dipalmitoyl-sn-glycero-3-phosphocholine and 1,2-dimyristoyl-sn-glycero-3-phosphocholine headgroup conformations were examined using deuterium nuclear magnetic resonance. Isothermal compression was found to produce a decrease in the choline alpha deuteron quadrupole splitting and increases in the choline beta and gamma deuteron quadrupole splittings. A similar counterdirectional change, seen in the presence of positive surface charge, has been attributed to tilting of the headgroup away from the bilayer surface in response to the torque exerted on the phosphocholine dipole by positive surface charges. The direction of the change in headgroup deuteron quadrupole splitting is consistent with the pressure-induced reduction in area per lipid in the liquid crystalline phase, which can be inferred from the ordering of phospholipid acyl chains under comparable conditions. The temperature dependences of the headgroup deuteron quadrupole splittings were also examined. It was found that at elevated pressure, the alpha splitting was insensitive to temperature, whereas the beta and gamma splittings decreased. The response of the beta deuteron splitting to temperature was found to be weaker at elevated pressure than at ambient pressure. PMID:8527666

  15. Dissociative recombination of N2H+

    NASA Astrophysics Data System (ADS)

    dos Santos, S. Fonseca; Ngassam, V.; Orel, A. E.; Larson, Å.

    2016-08-01

    The direct and indirect mechanisms of dissociative recombination of N2H+ are theoretically studied. At low energies, the electron capture is found to be driven by recombination into bound Rydberg states, while at collision energies above 0.1 eV, the direct capture and dissociation along electronic resonant states becomes important. Electron-scattering calculations using the complex Kohn variational method are performed to obtain the scattering matrix as well as energy positions and autoionization widths of resonant states. Potential-energy surfaces of electronic bound states of N2H and N2H+ are computed using structure calculations with the multireference configuration interaction method. The cross section for the indirect mechanism is calculated using a vibrational frame transformation of the elements of the scattering matrix at energies just above the ionization threshold. Here vibrational excitations of the ionic core from v =0 to v =1 and v =2 for all three normal modes are considered and autoionization is neglected. The cross section for the direct dissociation along electronic resonant states is computed with wave-packet calculations using the multiconfiguration time-dependent Hartree method, where all three internal degrees of freedom are considered. The calculated cross sections are compared to measurements.

  16. SNF2H promotes hepatocellular carcinoma proliferation by activating the Wnt/β-catenin signaling pathway

    PubMed Central

    Wang, Yanan; Qin, Juanxiu; Liu, Qian; Hong, Xufen; Li, Tianming; Zhu, Yuanjun; He, Lei; Zheng, Bing; Li, Min

    2016-01-01

    Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide and has an extremely poor prognosis. Surgical resection is always inapplicable to HCC patients diagnosed at an advanced tumor stage. The mechanisms underlying HCC cell proliferation remain obscure. In the present study, SWItch/sucrose nonfermentable catalytic subunit SNF2 (SNF2H) expression was tested in HCC tissues and Wnt/β-catenin pathway activation upon overexpression of SNF2H or knockdown of SNF2H expression was investigated in cultured HCC cells. It was demonstrated that SNF2H is a vital factor for HCC growth. The SNF2H expression level is increased in HCC tissues compared with paratumoral liver tissues. SNF2H promotes HCC cell proliferation and colony formation ability in vitro. SNF2H may increase the protein level of β-catenin and enhance its nuclear accumulation in HCC cells, thereby leading to the activation of the Wnt/β-catenin signaling pathway. In conclusion, the present results indicate that SNF2H plays a vital role in HCC cell growth, suggesting that SNF2H may be a promising therapeutic target for HCC treatment. PMID:27446433

  17. Hyperfine-induced quadrupole moments of alkali-metal-atom ground states and their implications for atomic clocks

    NASA Astrophysics Data System (ADS)

    Derevianko, Andrei

    2016-01-01

    Spherically symmetric ground states of alkali-metal atoms do not posses electric quadrupole moments. However, the hyperfine interaction between nuclear moments and atomic electrons distorts the spherical symmetry of electronic clouds and leads to nonvanishing atomic quadrupole moments. We evaluate these hyperfine-induced quadrupole moments using techniques of relativistic many-body theory and compile results for Li, Na, K, Rb, and Cs atoms. For heavy atoms we find that the hyperfine-induced quadrupole moments are strongly (two orders of magnitude) enhanced by correlation effects. We further apply the results of the calculation to microwave atomic clocks where the coupling of atomic quadrupole moments to gradients of electric fields leads to clock frequency uncertainties. We show that for 133Cs atomic clocks, the spatial gradients of electric fields must be smaller than 30 V /cm2 to guarantee fractional inaccuracies below 10-16.

  18. Synthesis Of [2h, 13c] And [2h3, 13c]Methyl Aryl Sulfides

    DOEpatents

    Martinez, Rodolfo A.; Alvarez, Marc A.; Silks, III, Louis A.; Unkefer, Clifford J.

    2004-03-30

    The present invention is directed to labeled compounds, [.sup.2 H.sub.1, .sup.13 C], [.sup.2 H.sub.2, .sup.13 C] and [.sup.2 H.sub.3, .sup.13 C]methyl aryl sulfides wherein the .sup.13 C methyl group attached to the sulfur of the sulfide includes exactly one, two or three deuterium atoms and the aryl group is selected from the group consisting of 1-naphthyl, substituted 1-naphthyl, 2-naphthyl, substituted 2-naphthyl, and phenyl groups with the structure ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, and R.sub.5 are each independently, hydrogen, a C.sub.1 -C.sub.4 lower alkyl, a halogen, an amino group from the group consisting of NH.sub.2, NHR and NRR' where R and R' are each a C.sub.1 -C.sub.4 lower alkyl, a phenyl, or an alkoxy group. The present invention is also directed to processes of preparing [.sup.2 H.sub.1, .sup.13 C], [.sup.2 H.sub.2,.sup.13 C] and [.sup.2 H.sub.3, .sup.13 C]methyl aryl sulfides wherein the .sup.13 C methyl group attached to the sulfur of the sulfide includes exactly one, two or three deuterium atoms. The present invention is also directed to the labeled compounds of [.sup.2 H.sub.1, .sup.13 C]methyl iodide and [.sup.2 H.sub.2, .sup.13 C]methyl iodide.

  19. QUADRUPOLE BEAM-BASED ALIGNMENT AT RHIC.

    SciTech Connect

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

    2005-05-16

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

  20. Interrelations between the pairing and quadrupole interactions in the microscopic Shell Model

    NASA Astrophysics Data System (ADS)

    Drumev, K. P.; Georgieva, A. I.

    2016-01-01

    We explore the dynamical symmetries of the shell model number conserving algebra, which define three types of pairing and quadrupole phases, with the aim to obtain the prevailing phase or phase transition for the real nuclear systems in a single shell. This is achieved by establishing a correspondence between each of the pairing bases with the Elliott's SU(3) basis that describes collective rotation of nuclear systems. This allows for a complete classification of the basis states of different number of particles in all the limiting cases. The probability distribution of the SU(3) basis states within theirs corresponding pairing states is also obtained. The relative strengths of dynamically symmetric quadrupole-quadrupole interaction in respect to the isoscalar, isovector and total pairing interactions define a control parameter, which estimates the importance of each term of the Hamiltonian in the correct reproduction of the experimental data for the considered nuclei.

  1. Local structure and molecular motions in imidazolium hydrogen malonate crystal as studied by 2H and 13C NMR

    NASA Astrophysics Data System (ADS)

    Mizuno, M.; Chizuwa, M.; Umiyama, T.; Kumagai, Y.; Miyatou, T.; Ohashi, R.; Ida, T.; Tansho, M.; Shimizu, T.

    2015-04-01

    The local structure and molecular motion of the imidazolium hydrogen malonate crystal were investigated using solid-state 2H and 13C NMR. The imidazolium ion undergoes isotropic rotation, which is correlated with a defect in the crystal, as observed by 2H NMR broadline spectra above 263 K. A 180∘ flip of the imidazolium ion in the regular site was observed from 2H NMR quadrupole Carr-Purcell-Meiboom-Gill (QCPMG) spectra. The Grotthuss mechanism was accompanied by a 180∘ flip of the imidazolium ion in regular sites. Moreover, the proton transfer associated with the imidazolium ion of the defective crystal is important for proton conductivity of the imidazolium hydrogen malonate crystal.

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

    SciTech Connect

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

    1994-12-01

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

  3. 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.

  4. Clusterization and quadrupole deformation in nuclei

    SciTech Connect

    Cseh, J.; Algora, A.; Antonenko, N. V.; Jolos, R. V.; Scheid, W.; Darai, J.; Hess, P. O.

    2006-04-26

    We study the interrelation of the clusterization and quadrupole deformation of atomic nuclei, by applying cluster models. Both the energetic stability and the exclusion principle is investigated. Special attention is paid to the relative orientations of deformed clusters.

  5. 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

  6. Klystron having electrostatic quadrupole focusing arrangement

    DOEpatents

    Maschke, Alfred W.

    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.

  7. 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.

  8. Radiofrequency quadrupole accelerators and their applications

    SciTech Connect

    Stokes, R.H.; Wangler, T.P.

    1988-01-01

    This review of Radiofrequency Quadrupole (RFQ) Acelerators contains a short history of Soviet and Los Alamos RFQ developments, RFQ beam dynamics, resonator structures, and the characteristics and performance of RFQ accelerators. (AIP)

  9. 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.

  10. 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.

  11. 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.

  12. Quadrupole magnet field mapping for FRIB

    NASA Astrophysics Data System (ADS)

    Portillo, M.; Amthor, A. M.; Chouhan, S.; Cooper, K.; Gehring, A.; Hausmann, M.; Hitchcock, S.; Kwarsick, J.; Manikonda, S.; Sumithrarachchi, C.

    2013-12-01

    Extensive magnetic field map measurements have been done on a newly built superconducting quadrupole triplet with sextupole and octupole coils nested within every quadrupole. The magnetic field multipole composition and fringe field distributions have been analyzed and an improved parameterization of the field has been developed within the beam transport simulation framework. Parameter fits yielding standard deviations as low as 0.3% between measured and modeled values are reported here.

  13. Permanent magnet edge-field quadrupole

    DOEpatents

    Tatchyn, Roman O.

    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.

  14. 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.

  15. 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.

    1988-10-01

    A laced permanent magnet quadrupole drift tube magnet has been constructed for a proof-of-principle test. The magnet is a conventional tape-wound quadrupole electromagnet, using iron pole- pieces, with the addition of permanent magnet material (neodymium iron) between the poles to reduce the effects of saturation. The iron is preloaded with magnetic flux generated by the permanent magnet material, resulting in an asymmetrical saturation curve. Since the polarity of the quadrupole magnets in a drift tube linac is not reversed we can take advantage of this asymmetrical saturation to provide greater focusing strength. The magnet configuration has been optimized and the vanadium permendur poles needed in a conventional quadrupole have been replaced with iron poles. The use of permanent magnet material has allowed us to increase the focusing strength of the magnet by about 20% over that of a conventional tape-wound quadrupole. Comparisons will be made between this magnet and the conventional tape-wound quadrupole. 3 refs., 5 figs.

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

    SciTech Connect

    Minkov, N. Drenska, S. B.; Yotov, P.; Bonatsos, D. Scheid, W.

    2007-08-15

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

  17. Robust correlations between quadrupole moments of low-lying 2+ states within random-interaction ensembles

    NASA Astrophysics Data System (ADS)

    Lei, Y.

    2016-02-01

    In random-interaction ensembles, three proportional correlations between quadrupole moments of the first two Iπ=2+ states robustly emerge, including Q (21+) =±Q (22+) correlations previously remarked by a realistic nuclear survey, and the Q (22+) =-3/7 Q (21+) correlation, which is only observed in the s d -boson space. These correlations can be microscopically characterized by the rotational SU(3) symmetry and quadrupole vibrational U(5) limit, respectively, according to the Elliott model and the s d -boson mean-field theory. The anharmonic vibration may be another phenomenological interpretation for the Q (21+) =-Q (22+) correlation, whose spectral evidence, however, is insufficient.

  18. 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.

  19. Chromatin remodeling enzyme Snf2h regulates embryonic lens differentiation and denucleation.

    PubMed

    He, Shuying; Limi, Saima; McGreal, Rebecca S; Xie, Qing; Brennan, Lisa A; Kantorow, Wanda Lee; Kokavec, Juraj; Majumdar, Romit; Hou, Harry; Edelmann, Winfried; Liu, Wei; Ashery-Padan, Ruth; Zavadil, Jiri; Kantorow, Marc; Skoultchi, Arthur I; Stopka, Tomas; Cvekl, Ales

    2016-06-01

    Ocular lens morphogenesis is a model for investigating mechanisms of cellular differentiation, spatial and temporal gene expression control, and chromatin regulation. Brg1 (Smarca4) and Snf2h (Smarca5) are catalytic subunits of distinct ATP-dependent chromatin remodeling complexes implicated in transcriptional regulation. Previous studies have shown that Brg1 regulates both lens fiber cell differentiation and organized degradation of their nuclei (denucleation). Here, we employed a conditional Snf2h(flox) mouse model to probe the cellular and molecular mechanisms of lens formation. Depletion of Snf2h induces premature and expanded differentiation of lens precursor cells forming the lens vesicle, implicating Snf2h as a key regulator of lens vesicle polarity through spatial control of Prox1, Jag1, p27(Kip1) (Cdkn1b) and p57(Kip2) (Cdkn1c) gene expression. The abnormal Snf2h(-/-) fiber cells also retain their nuclei. RNA profiling of Snf2h(-/) (-) and Brg1(-/-) eyes revealed differences in multiple transcripts, including prominent downregulation of those encoding Hsf4 and DNase IIβ, which are implicated in the denucleation process. In summary, our data suggest that Snf2h is essential for the establishment of lens vesicle polarity, partitioning of prospective lens epithelial and fiber cell compartments, lens fiber cell differentiation, and lens fiber cell nuclear degradation. PMID:27246713

  20. Ferrimagnetism in MnFeF/sub 5/. 2H/sub 2/O

    SciTech Connect

    Jones, E.R. Jr.; Van Hine, C.; Datta, T.; Cathey, L.; Karraker, D.G.

    1985-11-06

    The magnetic susceptibility of MnFeF/sub 5/.2H/sub 2/O was measured at temperatures from 5 to 300 K for applied fields of up to 1 kOe with a SQUID susceptometer. A ferrimagnetic phase transition was observed at 38 +/- 0.25 K. At temperatures between 200 and 300 K the susceptibility followed a Curie-Weiss law chi = C/(T-Theta) with Theta = -164 K and an effective magnetic moment of 7.4 +/- 0.1 ..mu../sub B/. The Moessbauer resonance spectrum gave a quadrupole-split doublet with an isomer shift of 0.483 mm/s relative to ..cap alpha..-iron, indicating that all of the iron was Fe/sup 3 +/. 13 references, 4 figures, 2 tables.

  1. 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.

  2. Induced CMB quadrupole from pointing offsets

    NASA Astrophysics Data System (ADS)

    Moss, Adam; Scott, Douglas; Sigurdson, Kris

    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 Y2, -1 component in Ecliptic co-ordinates. The dominant strength of this component in the measured quadrupole suggests that one should exercise increased caution in interpreting its estimated amplitude. The Planck satellite has a different scan strategy which does not so directly couple the dipole and quadrupole in this way and will soon provide an independent measurement.

  3. 14N Chemical Shifts and Quadrupole Coupling Constants of Inorganic Nitrates

    NASA Astrophysics Data System (ADS)

    Marburger, Simon P.; Fung, B. M.; Khitrin, A. K.

    2002-02-01

    The isotropic chemical shift and the nuclear quadrupole coupling constant for 14N were obtained for 14 inorganic nitrates by solid-state MAS NMR measurements at two different field strengths, 9.4 and 11.7 T. The compounds studied were polycrystalline powders of AgNO3, Al(NO3)3, Ba(NO3)2, Ca(NO3)2, CsNO3, KNO3, LiNO3, Mg(NO3)2, NaNO3, Pb(NO3)2, RbNO3, Sr(NO3)2, Th(NO3)4·4H2O, and UO2(NO3)2·3H2O. Even though the spectra show broadening due to 14N quadrupole interactions, linewidths of a few hundred hertz and a good signal-to-noise ratio were achieved. From the position of the central peaks at the two fields, the chemical shifts and the nuclear quadrupole coupling constants were calculated. The chemical shifts for all compounds studied range from 282 to 342 ppm with respect to NH4Cl. The nuclear quadrupole coupling constants range from 429 kHz for AgNO3 to 993 kHz for LiNO3. These data are compared with those available in the literature.

  4. Microwave measurements of cobalt and nitrogen quadrupole coupling in Co(CO)3NO

    NASA Astrophysics Data System (ADS)

    Kukolich, S. G.; Roehrig, M. A.; Haubrich, S. T.; Shea, J. A.

    1991-01-01

    J=2→3, 3→4, 4→5, and 5→6 transitions in the oblate symmetric top molecule cobalt tricarbonyl nitrosyl were measured using a Flygare-Balle type pulsed beam microwave spectrometer. K=0 and K=3 transitions were observed for J=3→4 and 4→5. Hyperfine structure due to 59Co and 14N nuclear quadrupole coupling interactions was well resolved. The measured quadrupole coupling strengths are eQqcc (59Co)=35.14(30) MHz and eQqcc (14N)=-1.59(10). Measured rotation and distortion constants are B0=1042.1590(4) MHz and Dj =0.17(8) kHz. The measured B value is 4% smaller than the B value calculated from electron diffraction data. Spin-rotation and a quadrupole distortion term were also obtained for 59Co.

  5. Laboratory automation of a quadrupole mass spectrometer

    NASA Astrophysics Data System (ADS)

    Thompson, J. M.

    1983-12-01

    Efforts directed toward interfacing an LSI II bus of a PDP 11/23 desktop computer with a quadrupole mass spectrometer for the purpose of providing a convenient system whereby mass spectral data, of the products of thermal decomposition, may be rapidly acquired and processed under programmed conditions are described. The versatility and operations of the quadrupole mass spectrometer are discussed as well as the procedure for configurating the LSI II bus of the PDP 11/23 desktop computer for interfacing with the quadrupole mass spectrometer system. Data from the mass filter and other units of the spectrometer are digitally transferred to the computer whereupon mass spectral data and related data are generated.

  6. Laboratory Automation of a Quadrupole Mass Spectrometer

    NASA Technical Reports Server (NTRS)

    Thompson, J. M.

    1983-01-01

    Efforts directed toward interfacing an LSI II bus of a PDP 11/23 desktop computer with a quadrupole mass spectrometer for the purpose of providing a convenient system whereby mass spectral data, of the products of thermal decomposition, may be rapidly acquired and processed under programmed conditions are described. The versatility and operations of the quadrupole mass spectrometer are discussed as well as the procedure for configurating the LSI II bus of the PDP 11/23 desktop computer for interfacing with the quadrupole mass spectrometer system. Data from the mass filter and other units of the spectrometer are digitally transferred to the computer whereupon mass spectral data and related data are generated.

  7. The large quadrupole of water molecules.

    PubMed

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

    2011-04-01

    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. PMID:21476758

  8. 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

  9. The large quadrupole of water molecules

    NASA Astrophysics Data System (ADS)

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

    2011-04-01

    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.

  10. Electric quadrupole transition probabilities for atomic lithium

    SciTech Connect

    Çelik, Gültekin; Gökçe, Yasin; Yıldız, 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 Hartree–Fock wavefunctions for expectation values of radii and the necessary energy values have been taken from the compilation at NIST. The results obtained with the present method agree very well with the Coulomb approximation results given by Caves (1975). Moreover, electric quadrupole transition probability values not existing in the literature for some highly excited levels have been obtained using the WBEPMT.

  11. SKEW QUADRUPOLE FOCUSING LATTICES AND APPLICATIONS.

    SciTech Connect

    PARKER,B.

    2001-06-18

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

  12. Magnetic Measurement Results of the LCLS Undulator Quadrupoles

    SciTech Connect

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

    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. Quantum phase transition in the spherical mean-field plus quadrupole-quadrupole and pairing model in a single-j shell

    NASA Astrophysics Data System (ADS)

    Li, Bo; Pan, Feng; Draayer, J. P.

    2016-04-01

    The quantum-phase-transitional behavior of the spherical shell-model mean field plus the geometric quadrupole-quadrupole and standard pairing model within a single-j shell is analyzed in detail. Various quantities, such as low-lying energy levels, some typical energy ratios, the overlaps of the excited states with those of the corresponding limiting cases, B (E 2 ) values and electric quadrupole moments of some low-lying states and their ratios, as functions of the control parameter of the model in a j =15 /2 shell are calculated as an example, in which only a crossover occurs due to the Pauli exclusion. The results show that there are noticeable changes within the crossover region of the rotation-like to the pair-excitation (superconducting) phase transition, especially in the half-filling case. As an application to realistic nuclear systems, a chain of isotones 212Rn-213Fr-214Ra-215Ac is chosen to be described by the model with valence protons in the 1 h9 /2 shell. As far as the low-lying energy levels, the experimentally observed B (E 2 ) values, and the electric quadrupole moment within the yrast band are concerned, these nuclei seem fitted reasonably well. The results indicate that these nuclei are all within the rotation-like to the pair-excitation phase transition near the crossover point.

  14. Molecular dynamics in paramagnetic materials as studied by magic-angle spinning 2H NMR spectra.

    PubMed

    Mizuno, Motohiro; Suzuki, You; Endo, Kazunaka; Murakami, Miwa; Tansho, Masataka; Shimizu, Tadashi

    2007-12-20

    A magic-angle spinning (MAS) 2H NMR experiment was applied to study the molecular motion in paramagnetic compounds. The temperature dependences of 2H MAS NMR spectra were measured for paramagnetic [M(H2O)6][SiF6] (M=Ni2+, Mn2+, Co2+) and diamagnetic [Zn(H2O)6][SiF6]. The paramagnetic compounds exhibited an asymmetric line shape in 2H MAS NMR spectra because of the electron-nuclear dipolar coupling. The drastic changes in the shape of spinning sideband patterns and in the line width of spinning sidebands due to the 180 degrees flip of water molecules and the reorientation of [M(H2O)6]2+ about its C3 axis were observed. In the paramagnetic compounds, paramagnetic spin-spin relaxation and anisotropic g-factor result in additional linebroadening of each of the spinning sidebands. The spectral simulation of MAS 2H NMR, including the effects of paramagnetic shift and anisotropic spin-spin relaxation due to electron-nuclear dipolar coupling and anisotropic g-factor, was performed for several molecular motions. Information about molecular motions in the dynamic range of 10(2) s(-1)2H MAS NMR spectra when these paramagnetic effects are taken into account. PMID:18027914

  15. Rate Coefficients of C2H with C2H4, C2H6, and H2 from 150 to 359 K

    NASA Technical Reports Server (NTRS)

    Opansky, Brian J.; Leone, Stephen R.

    1996-01-01

    Rate coefficients for the reactions C2H with C2H4, C2H6, and H2 are measured over the temperature range 150-359 K using transient infrared laser absorption spectroscopy. The ethynyl radical is formed by photolysis of C2H2 with a pulsed excimer laser at 193 nm, and its transient absorption is monitored with a color center laser on the Q(sub 11)(9) line of the A(sup 2) Pi-Chi(sup 2) Sigma transition at 3593.68 cm(exp -1). Over the experimental temperature range 150-359 K the rate constants of C2H with C2H4, C2H6, and H2 can be fitted to the Arrhenius expressions k(sub C2H4) = (7.8 +/- 0.6) x 10(exp -11) exp[(134 +/- 44)/T], k(sub C2H6) = (3.5 +/- 0.3) x 10(exp -11) exp[(2.9 +/- 16)/T], and k(sub H2) = (1.2 +/- 0.3) x 10(exp -11) exp[(-998 +/- 57)]/T cm(exp 3) molecule(exp -1) sec(exp -1). The data for C2H with C2H4 and C2H6 indicate a negligible activation energy to product formation shown by the mild negative temperature dependence of both reactions. When the H2 data are plotted together with the most recent high-temperature results from 295 to 854 K, a slight curvature is observed. The H2 data can be fit to the non-Arrhenius form k(sub H2) = 9.2 x 10(exp -18) T(sup 2.17 +/- 0.50) exp[(-478 +/- 165)/T] cm(exp 3) molecules(exp -1) sec(exp -1). The curvature in the Arrhenius plot is discussed in terms of both quantum mechanical tunneling of the H atom from H2 to the C2H radical and bending mode contributions to the partition function.

  16. Self-, N2- and Ar-broadening and line mixing in HCN and C2H2

    NASA Technical Reports Server (NTRS)

    Pine, A. S.

    1993-01-01

    Self-, N2- and Ar-broadening coefficients were measured for the stretch-bend infrared combination bands nu-1 + nu-1/2 (4004/cm) of HCN and nu-1 + nu-1/5 (4091/cm) of C2H2, using a tunable difference-frequency laser. At atmospheric pressures, the Q branches of these bands exhibit significant rotational narrowing or line mixing. The broadening coefficients are fit with empirical rotationally inelastic collision rate laws, which are then used to model the line mixing in the overlapped Q-branch profiles. Simple energy gap fitting laws appear to be suitable for the shorter-range intermolecular quadrupole-quadrupole and induction forces, whereas an energy-corrected-sudden scaling law works better for the longer-range dipole-dipole and dipole-quadrupole collision partners. In all cases, the line-coupling coefficients are substantially reduced from the rotationally inelastic rates fit to the broadening coefficients, indicating that 35-70 percent of the broadening may be due to other collisional mechanisms such as cross-relaxation to the degenerate H state vibrational level.

  17. Quantitation of methadone enantiomers in humans using stable isotope-labeled (2H3)-, (2H5)-, and (2H8)Methadone

    SciTech Connect

    Nakamura, K.; Hachey, D.L.; Kreek, M.J.; Irving, C.S.; Klein, P.D.

    1982-01-01

    A new technique for simultaneous stereoselective kinetic studies of methadone enantiomers was developed using three deuterium-labeled forms of methadone and GLC-chemical-ionization mass spectrometry. A racemic mixture (1:1) of (R)-(-)-(2H5)methadone (l-form) and (S)-(R)-(2H3)methadone (d-form) was administered orally in place of a single daily dose of unlabeled (+/-)-(2H0)methadone in long-term maintenance patients. Racemic (+/-)-(2H8)methadone was used as an internal standard for the simultaneous quantitation of (2H0)-, (2H3)-, and (2H5)methadone in plasma and urine. A newly developed extraction procedure, using a short, disposable C18 reversed-phase cartridge and improved chemical-ionization procedures employing ammonia gas, resulted in significant reduction of the background impurities contributing to the ions used for isotopic abundance measurements. These improvements enabled the measurement of labeled plasma methadone levels for 120 hr following a single dose. This methodology was applied to the study of methadone kinetics in two patients; in both patients, the analgesically active l-enantiomer of the drug had a longer plasma elimination half-life and a smaller area under the plasma disappearance curve than did the inactive d-form.

  18. Model dependence of the {sup 2}H electric dipole moment

    SciTech Connect

    Afnan, I. R.; Gibson, B. F.

    2010-12-15

    Background: Direct measurement of the electric dipole moment (EDM) of the neutron is in the future; measurement of a nuclear EDM may well come first. The deuteron is one nucleus for which exact model calculations are feasible. Purpose: We explore the model dependence of deuteron EDM calculations. Methods: Using a separable potential formulation of the Hamiltonian, we examine the sensitivity of the deuteron EDM to variation in the nucleon-nucleon interaction. We write the EDM as the sum of two terms, the first depending on the target wave function with plane-wave intermediate states, and the second depending on intermediate multiple scattering in the {sup 3}P{sub 1} channel, the latter being sensitive to the off-shell behavior of the {sup 3}P{sub 1} amplitude. Results: We compare the full calculation with the plane-wave approximation result, examine the tensor force contribution to the model results, and explore the effect of short-range repulsion found in realistic, contemporary potential models of the deuteron. Conclusions: Because one-pion exchange dominates the EDM calculation, separable potential model calculations will provide an adequate description of the {sup 2}H EDM until such time as a measurement better than 10% is obtained.

  19. Development of integrated superconducting quadrupole doublet modules for operation in the SIS100 accelerator

    NASA Astrophysics Data System (ADS)

    Meier, J.; Bleile, A.; Ceballos Velasco, J.; Fischer, E.; Hess, G.; Macavei, J.; Spiller, P.

    2015-12-01

    The FAIR project (Facility for Antiproton and Ion Research) evolves and builds an international accelerator- and experimental facility for basic research activities in various fields of modern physics. Within the course of this project, integrated quadrupole doublet modules are in development. The quadrupole doublet modules provide a pair of superconducting main quadrupoles (focusing and defocusing), corrector magnets, cryogenic collimators and beam position monitors as integrated sets of ion-optical elements. Furthermore LHe cooled beam pipes and vacuum cold-warm transitions are used as ultra-high vacuum components for beam transportation. Superconducting bus bars are used for 13 kA current supply of the main quadrupole magnets. All components are integrated as one common cold mass into one cryostat. High temperature super conductor local current leads will be applied for the low current supply of corrector magnets. The quadrupole doublet modules will be operated in the SIS100 heavy ion accelerator, the core component of the FAIR project. A first version of a corrector magnet has already been manufactured at the Joint Institute for Nuclear Research (JINR), Russia, and is now ready for testing. The ion-optical lattice structure of SIS100 requires multiple configurations of named components. Eleven different configurations, organized in four categories, provide the required quadrupole doublet module setups. The high integration level of multiple ion-optical, mechanical and cryogenic functions, based on requirements of operation safety, is leading towards a sophisticated mechanical structure and cooling solution, to satisfy the demanding requirements on position preservation during thermal cycling. The mechanical and cryogenic design solutions will be discussed.

  20. SNF2H interacts with XRCC1 and is involved in repair of H2O2-induced DNA damage.

    PubMed

    Kubota, Yoshiko; Shimizu, Shinji; Yasuhira, Shinji; Horiuchi, Saburo

    2016-07-01

    The protein XRCC1 has no inherent enzymatic activity, and is believed to function in base excision repair as a dedicated scaffold component that coordinates other DNA repair factors. Repair foci clearly represent the recruitment and accumulation of DNA repair factors at sites of damage; however, uncertainties remain regarding their organization in the context of nuclear architecture and their biological significance. Here we identified the chromatin remodeling factor SNF2H/SMARCA5 as a novel binding partner of XRCC1, with their interaction dependent on the casein kinase 2-mediated constitutive phosphorylation of XRCC1. The proficiency of repairing H2O2-induced damage was strongly impaired by SNF2H knock-down, and similar impairment was observed with knock-down of both XRCC1 and SNF2H simultaneously, suggesting their role in a common repair pathway. Most SNF2H exists in the nuclear matrix fraction, forming salt extraction-resistant foci-like structures in unchallenged nuclei. Remarkably, damage-induced formation of both PAR and XRCC1 foci depended on SNF2H, and the PAR and XRCC1 foci co-localized with the SNF2H foci. We propose a model in which a base excision repair complex containing damaged chromatin is recruited to specific locations in the nuclear matrix for repair, with this recruitment mediated by XRCC1-SNF2H interaction. PMID:27268481

  1. 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.

  2. 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

  3. Synthesis Of [2h, 13c]M [2h2m 13c], And [2h3,, 13c] Methyl Aryl Sulfones And Sulfoxides

    DOEpatents

    Martinez, Rodolfo A.; Alvarez, Marc A.; Silks, III, Louis A.; Unkefer, Clifford J.; Schmidt, Jurgen G.

    2004-07-20

    The present invention is directed to labeled compounds, [.sup.2 H.sub.1, .sup.13 C], [.sup.2 H.sub.2, .sup.13 C] and [.sup.2 H.sub.3, .sup.13 C]methyl aryl sulfones and [.sup.2 H.sub.1, .sup.13 C], [.sup.2 H.sub.2, .sup.13 C] and [.sup.2 H.sub.3, .sup.13 C]methyl aryl sulfoxides, wherein the .sup.13 C methyl group attached to the sulfur of the sulfone or sulfoxide includes exactly one, two or three deuterium atoms and the aryl group is selected from the group consisting of 1-naphthyl, substituted 1-naphthyl, 2-naphthyl, substituted 2-naphthyl, and phenyl groups with the structure: ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are each independently, hydrogen, a C.sub.1 -C.sub.4 lower alkyl, a halogen, an amino group from the group consisting of NH.sub.2, NHR and NRR' where R and R' are each a C.sub.1 -C.sub.4 lower alkyl, a phenyl, or an alkoxy group. The present invention is also directed to processes of preparing methyl aryl sulfones and methyl aryl sulfoxides.

  4. Investigation of multiaxial molecular dynamics by 2H MAS NMR spectroscopy.

    PubMed

    Kristensen, J H; Hoatson, G L; Vold, R L

    1998-11-01

    The technique of 2H MAS NMR spectroscopy is presented for the investigation of multiaxial molecular dynamics. To evaluate the effects of discrete random reorientation a Lie algebraic formalism based on the stochastic Liouville-von Neumann equation is developed. The solution to the stochastic Liouville-von Neumann equation is obtained both in the presence and absence of rf irradiation. This allows effects of molecular dynamics to be evaluated during rf pulses and extends the applicability of the formalism to arbitrary multiple pulse experiments. Theoretical methods are presented for the description of multiaxial dynamics with particular emphasis on the application of vector parameters to represent molecular rotations. Numerical time and powder integration algorithms are presented that are both efficient and easy to implement computationally. The applicability of 2H MAS NMR spectroscopy for investigating molecular dynamics is evaluated from theoretical spectra. To demonstrate the potential of the technique the dynamics of thiourea-2H4 is investigated experimentally. From a series of variable temperature MAS and quadrupole echo spectra it has been found that the dynamics can be described by composite rotation about the CS and CN bonds. Both experiments are sensitive to the fast CS rotation which is shown to be described by the Arrhenius parameters E(CS) = 46.4 +/- 2.3 kJ mol(-1) and ln(A(CS))= 32.6 +/- 0.9. The MAS experiment represents a significant improvement by simultaneously allowing the dynamics of the slow CN rotation to be fully characterized in terms of E(CN) = 56.3 +/- 3.4 kJ mol(-1) and ln(A(CN)) = 25.3 +/- 1.1. PMID:9875600

  5. Application of the triaxial quadrupole-octupole rotor to the ground and negative-parity levels of actinide nuclei

    NASA Astrophysics Data System (ADS)

    Nadirbekov, M. S.; Minkov, N.; Strecker, M.; Scheid, W.

    2016-03-01

    In this work, we examine the possibility to describe yrast positive- and negative-parity excitations of deformed even-even nuclei through a collective rotation model in which the nuclear surface is characterized by triaxial quadrupole and octupole deformations. The nuclear moments of inertia are expressed as sums of quadrupole and octupole parts. By assuming an adiabatic separation of rotation and vibration degrees of freedom, we suppose that the structure of the positive- and negative-parity bands may be determined by the triaxial-rigid-rotor motion of the nucleus. By diagonalizing the Hamiltonian in a symmetrized rotor basis with embedded parity, we obtain a model description for the yrast positive- and negative-parity bands in several actinide nuclei. We show that the energy displacement between the opposite-parity sequences can be explained as the result of the quadrupole-octupole triaxiality.

  6. Investigation hydrogen-bonding capabilities of modified amide groups using calculated nuclear quadruple coupling constants

    NASA Astrophysics Data System (ADS)

    Elmi, F.; Hadipour, N. L.; Safinezhad, F.

    2003-07-01

    Nuclear quadrupole coupling constants, χs, for 17 chemical species are calculated. These are retroamide, N-hydroxamide, N-amino amide, thioamide, methylamine and complexes which amide generates with retroamide and other modified amides. The charge distributions around quadrupolar nuclei are most affected upon intermolecular hydrogen bond formations. χs of these nuclei are computed using ab initio calculations. Some of our findings for average values of χs of 2H, 14N and 17O in hydrogen bonds are 200.00 kHz, 4.40 MHz and 10.50 MHz, respectively. There is a fairly linear dependency between RO⋯H and the logarithm of 2H χs. This correlation is approximately linear for 17O and 14N nuclei.

  7. Muonic x-ray measurement of the monopole and quadrupole charge parameters of 154-158,160Gd

    NASA Astrophysics Data System (ADS)

    Laubacher, D. B.; Tanaka, Y.; Steffen, R. M.; Shera, E. B.; Hoehn, M. V.

    1983-04-01

    Monopole and quadrupole charge distributions of 154Gd, 155Gd, 156Gd, 157Gd, 158Gd, and 160Gd were investigated by muonic-atom K and L x-ray measurements. The model-independent Barrett charge radii Rk and the isotope shifts ΔRk were measured, and values of and Δ were deduced. A pronounced even-odd staggering effect of the nuclear charge radii was observed for the series 156-158Gd. The quadrupole moments of the first excited states of the even-A Gd nuclei were determined to be Q154(2+)=-1.82(4) e b, Q156(2+)=-1.93(4) e b, Q158(2+)=-2.01(4) e b, and Q160(2+)=-2.08(4) e b, and the quadrupole moments of the 32- ground states of the odd-A 155,157Gd nuclei were determined to be Q155(32-)=1.27(3) e b and Q157(32-)=1.35(3) e b. Comparison with a separate measurement of the odd-A ground-state quadrupole moments based on the static hyperfine splitting of the muonic M x rays showed that the model error in the extracted quadrupole moments of these nuclei is less than 2 percent. The quadrupole moments and the B(E2) values obtained in the present experiment for the low-lying Gd states are in satisfactory agreement with the axially symmetric rotational model. However, the 154Gd nucleus exhibits a considerable softness as indicated by the isomer shift of the 2+ excited state and by the experimental value of the ratio Q(2+)B(E2:0+-->2+). NUCLEAR STRUCTURE 154-158,160Gd; measured muonic x-ray spectra; deduced monopole and quadrupole charge parameters; isotope and isomer shifts.

  8. On quadrupole vibrations in nearly spherical nuclei

    NASA Astrophysics Data System (ADS)

    Yates, S. W.

    2012-09-01

    A new understanding of low-lying quadrupole vibrations in nuclei is emerging through lifetime measurements performed with fast neutrons at the accelerator laboratory of the University of Kentucky in combination with high-sensitivity measurements with other probes. In the stable cadmium nuclei, which have long been considered to be the best examples of vibrational behavior, we find that many E2 transition probabilities are well below harmonic vibrator expectations, and the B(E2)s cannot be explained with calculations incorporating configuration mixing between vibrational phonon states and intruder excitations. These data place severe limits on the collective models, and it is suggested that the low-lying levels of the Cd isotopes may not be of vibrational origin. An additional example of an apparent quadrupole vibrational nucleus, 62Ni, is considered.

  9. Permanent-magnet quadrupoles in RFQ Linacs

    SciTech Connect

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

    1985-10-01

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

  10. Quench antennas for RHIC quadrupole magnets

    SciTech Connect

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

    1995-05-01

    Quench antennas for RHIC quadrupole magnets are being developed jointly by KEK and BNL. A quench antenna is a device to localize a quench origin using arrays of pick-up coils lined up along the magnet bore. Each array contains four pick-up coils: sensitive to normal sextupole, skew sextupole, normal octupole, and skew octupole field. This array configuration allows an azimuthal localization of a quench front while a series of arrays gives an axial localization and a quench propagation velocity. Several antennas have been developed for RHIC magnets and they are now routinely used for quench tests of production magnets. The paper discusses the description of the method and introduces a measured example using an antenna designed for quadrupole magnets.

  11. McDonnell F2H-3 Banshee

    NASA Technical Reports Server (NTRS)

    1957-01-01

    McDonnell F2H-3 Banshee: To more clearly mark the operators of this McDonnell F2H-3 Banshee, the 'VY' of Navy has been painted out and the appropriate lettering to spell NACA has been applied. Note that the second 'A' is of a different shape than the first. The 'Banjo' retained Navy titles on the wings, however.

  12. Prediction of the existence of the N2H- molecular anion

    NASA Astrophysics Data System (ADS)

    Lique, François; Halvick, Philippe; Stoecklin, Thierry; Hochlaf, Majdi

    2012-06-01

    We predict the existence of the N2H- anion from first principle calculations. We present the three-dimensional potential energy surface and the bound states of the N2H-/D- van der Waals anion. The electronic calculations were performed using state-of-the-art ab initio methods and the nuclear motions were solved using a quantum close-coupling scattering theory. A T-shaped equilibrium structure was found, with a well depth of 349.1 cm-1, where 18 bound states have been located for N2H- and 25 for N2D- for total angular momentum J = 0. We also present the absorption spectra of the N2H- complex. This anion could be formed after low energy collisions between N2 and H- through radiative association. The importance of this prediction in astrophysics and the possible use of N2H- as a tracer of N2 and H- in the interstellar medium is discussed.

  13. 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.

  14. 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.

  15. Electrostatic quadrupole DC accelerators for BNCT applications

    SciTech Connect

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

    1994-04-01

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

  16. 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.

  17. Determination of muscle protein synthesis rates in fish using (2)H2O and (2)H NMR analysis of alanine.

    PubMed

    Marques, Cátia; Viegas, Filipa; Rito, João; Jones, John; Viegas, Ivan

    2016-09-15

    Following administration of deuterated water ((2)H2O), the fractional synthetic rate (FSR) of a given endogenous protein can be estimated by (2)H-enrichment quantification of its alanine residues. Currently, this is measured by mass spectrometry following a derivatization procedure. Muscle FSR was measured by (1)H/(2)H NMR analysis of alanine from seabass kept for 6 days in 5% (2)H-enriched saltwater, following acid hydrolysis and amino acid isolation by cation-exchange chromatography of muscle tissue. The analysis is simple and robust, and provides precise measurements of excess alanine (2)H-enrichment in the 0.1-0.4% range from 50 mmol of alanine recovered from muscle protein. PMID:27418547

  18. 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.

  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. Ab initio correlated calculations of rare-gas dimer quadrupoles

    NASA Astrophysics Data System (ADS)

    Donchev, Alexander G.

    2007-10-01

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

  1. Theoretical study of the bonding of Nb(2+) to CH2, C2H2, and C2H4

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles W., Jr.; Langhoff, Stephen R.; Partridge, Harry

    1991-01-01

    The bonding of Nb(2+) with CH2, C2H2, and C2H4 is studied by using electronic structure calculations that include high levels of electron correlation. The binding energy for NbCH2(2+) is in good agreement with the lower bound determined from the reaction with CH4 but is significantly smaller than the value determined from the binding energy and ionization potential of NbCH2(+). The calculations and a new interpretation of the experiment indicate that the larger value is in error primarily because the ionization potential of NbCH2(+) determined from bracketing charge-exchange reactions is too small. The computed binding energy of NbC2H2(2+) is in good agreement with experiment. The calculations show that the bonding is predominantly covalent in character for both NbCH2(2+) and NbC2H2(2+), whereas for NbC2H4(2+) the electronic states that are predominantly ionic and covalent are nearly degenerate. The trend in binding energies, CH2 greater than C2H2 greater than C2H4, is consistent with the energy required to prepare the ligands for bonding.

  2. Aberrations caused by mechanical misalignments in electrostatic quadrupole lens systems

    NASA Astrophysics Data System (ADS)

    Baranova, L. A.; Read, F. H.

    Image aberrations resulting from small misalignments in quadrupole lenses multiplets have been analysed. Analytical formulas for the coefficients of the beam displacement, astigmatism and coma associated with misalignments in a general quadrupole lens system have been derived. Numerical computations of systems of three and four quadrupole lenses have also been carried out. The aberration figures obtained for systems with and without a mechanical defect are compared. The aberration coefficients that have been obtained can be used for estimating tolerance limits for lens misalignments.

  3. Two methods of computing molecular dipole and quadrupole derivatives

    NASA Astrophysics Data System (ADS)

    Lazzeretti, P.; Zanasi, R.; Fowler, P. W.

    1988-01-01

    Polarized basis sets are used to compute dipole and quadrupole derivatives of the hydrides LiH, CH4, NH3, H2O, and HF. Analytic calculation of derivatives is compared with calculation via the dipole and quadrupole electric shielding tensors. With these basis sets, violation of the Hellmann-Feynman theorem is only about 0.01 a.u. in dipole derivatives and 0.02 a.u. in quadrupole derivatives.

  4. 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.

  5. The Microwave Spectrum of the HCOOCD_2H Species of Methyl Formate

    NASA Astrophysics Data System (ADS)

    Coudert, L. H.; Huet, T. R.; Margulès, L.; Motiyenko, R.; Mollendal, H.

    2010-06-01

    Methyl formate is a non-rigid molecule displaying internal rotation of its methyl group. The microwave spectra of its normal and mono deuterated HCOOCH_2D species have already been studied and values for the tunneling splitting due to the internal rotation were determined. The normal species displays a 405 MHz A/E splitting, the mono deuterated one, a smaller 84.76 MHz A'/A'' splitting. For the bideuterated species HCOOCD_2H, the value of this splitting is not known as its microwave spectrum has not been studied yet. In this paper experimental and theoretical investigations of the microwave spectrum of HCOOCD_2H are presented. More than 9000 transitions were measured with a submillimeter wave spectrometer. About 20 lines were recorded with a molecular beam spectrometer. Like for the mono deuterated species,^c depending on the location of the only hydrogen atom of the methyl group, two configurations arise. The C_s-symmetry H-in plane configuration displays a rigid rotator spectrum and its data was analyzed using a Watson-type Hamiltonian. The C_1-symmetry H-out of plane configuration undergoes the large amplitude internal rotation. Its data was analyzed using the so called water dimer formalism which allowed us to accurately reproduce the observed frequencies and to obtain the value of the tunneling splitting as well as the parameters involved in its rotational dependence. The hyperfine structure due to quadrupole coupling at the two deuterium atoms was also analyzed. Unexpectedly, for the H-out of plane configuration, the observed hyperfine patterns are neither those expected for two equivalent deuterium atoms nor those of a rigid molecule. Ilyushin, Kryvda, and Alekseev, J. Mol. Spec. 255 (2009) 32. Margulès, Coudert, Mollendal, Guillemin, Huet, and Janeckovà, J. Mol. Spec. 254 (2009) 55. Hougen, J. Mol. Spec. 114 (1985) 395; and Coudert and Hougen, J. Mol. Spec. 130 (1988) 86.

  6. 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.

  7. Noise reduction in negative-ion quadrupole mass spectrometry

    DOEpatents

    Chastagner, Philippe

    1993-01-01

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

  8. 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.

  9. Thermogravimetric-quadrupole mass-spectrometric analysis of geochemical samples.

    NASA Technical Reports Server (NTRS)

    Gibson, E. K., Jr.; Johnson, S. M.

    1972-01-01

    Thermogravimetric-quadrupole mass-spectrometric-analysis techniques can be used to study a wide variety of problems involving decomposition processes and identification of released volatile components. A recording vacuum thermoanalyzer has been coupled with a quadrupole mass spectrometer. The rapid scan capabilities of the quadrupole mass spectrometer are used to identify the gaseous components released. The capability of the thermogravimetric-quadrupole mass spectrometer to provide analytical data for identification of the released volatile components, for determination of their sequence of release and for correlation of thermal-decomposition studies is illustrated by an analysis of the Orgueil carbonaceous chondrite.

  10. C2H observations toward the Orion Bar

    NASA Astrophysics Data System (ADS)

    Nagy, Z.; Ossenkopf, V.; Van der Tak, F. F. S.; Faure, A.; Makai, Z.; Bergin, E. A.

    2015-06-01

    Context. The ethynyl radical (C2H) is one of the first radicals to be detected in the interstellar medium. Its higher rotational transitions have recently become available with the Herschel Space Observatory. Aims: We aim to constrain the physical parameters of the C2H emitting gas toward the Orion Bar. Methods: We analyze the C2H line intensities measured toward the Orion Bar CO+ Peak and Herschel/HIFI maps of C2H, CH, and HCO+ and a NANTEN map of [Ci]. We interpret the observed C2H emission using the combination of Herschel/HIFI and NANTEN data with radiative transfer and PDR models. Results: Five rotational transitions of C2H (from N = 6-5 up to N = 10-9) have been detected in the HIFI frequency range toward the CO+ peak of the Orion Bar. Based on the five detected C2H transitions, a single component rotational diagram analysis gives a rotation temperature of ~64 K and a beam-averaged C2H column density of 4 × 1013 cm-2. The rotational diagram is also consistent with a two-component fit, resulting in rotation temperatures of 43 ± 0.2 K and 123 ± 21 K and in beam-averaged column densities of ~8.3 × 1013 cm-2 and ~2.3 × 1013 cm-2 for the three lower-N and for the three higher-N transitions, respectively. The measured five rotational transitions cannot be explained by any single parameter model. According to a non-LTE model, most of the C2H column density produces the lower-N C2H transitions and traces a warm (Tkin ~ 100-150 K) and dense (n(H2) ~ 105-106 cm-3) gas. A small fraction of the C2H column density is required to reproduce the intensity of the highest-N transitions (N = 9-8 and N = 10-9) originating in a high-density (n(H2) ~5 × 106 cm-3) hot (Tkin ~ 400 K) gas. The total beam-averaged C2H column density in the model is 1014 cm-2. A comparison of the spatial distribution of C2H to those of CH, HCO+, and [Ci] shows the best correlation with CH. Conclusions: Both the non-LTE radiative transfer model and a simple PDR model representing the Orion Bar

  11. 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

  12. Static Electric Quadrupole Moments in the Ground State and K = 4-1 Bands in 168Er

    NASA Astrophysics Data System (ADS)

    Thakur, P.; Behra, M. S.; Dogra, R.; Bhati, A. K.; Bedi, S. C.

    2002-07-01

    The time differential perturbed angular correlation (TDPAC) technique has been used to study the nuclear quadrupole interactions of the first excited state of ground state rotational band (2+, 80 keV, T1/2 = 1.88 ns) and the band head of the = 41- band (41-,1094 keV, T1/2 = 120 ns) in the 168Er nucleus of a polycrystalline Er host. At room temperature we obtained the electric quadrupole interaction frequencies ω0(K= 0) = 457(15) Mrad/s and ω0(K= 4) = 69(2) Mrad/s, respectively, for the 2+ and 4- isomeric states of 168Er. The ratio of the spectroscopic quadrupole moments, i. e. Qs (K= 4)/Qs (K= 0) = 0.69(3), is independent of any model approximation and the electric field gradient at 168Er in the host metal

  13. Quantum-state tomography for quadrupole nuclei and its application on a two-qubit system

    NASA Astrophysics Data System (ADS)

    Bonk, F. A.; Sarthour, R. S.; Deazevedo, E. R.; Bulnes, J. D.; Mantovani, G. L.; Freitas, J. C.; Bonagamba, T. J.; Guimarães, A. P.; Oliveira, I. S.

    2004-04-01

    A method for performing quantum state tomography for quadrupole nuclei is presented in this paper. First, it is shown that upon appropriate phase cycling, the nuclear-magnetic-resonance (NMR) intensities of quadrupole nuclei depend only on diagonal elements of the density-matrix. Thus, a method for obtaining the density-matrix elements, which consists of dragging off-diagonal elements into the main diagonal using fine phase-controlled selective radio-frequency pulses, was derived. The use of the method is exemplified through 23 Na NMR (nuclear spin I=3/2 ) in a lyotropic liquid crystal at room temperature, in three applications: (a) the tomography of pseudopure states, (b) the tomography of the quadrupole free evolution of the density matrix, and (c) the unitary state evolution of each qubit in the system over the Bloch sphere upon the application of a Hadamard gate. Further applications in the context of pure NMR and in the context of quantum information processing, as well as generalizations for higher spins, are discussed.

  14. Interplay between the pairing and quadrupole interactions in the algebraic realization of the microscopic shell model

    NASA Astrophysics Data System (ADS)

    Drumev, Kalin; Georgieva, Ana

    2015-04-01

    We explore the algebraic realization of the Pairing-Plus-Quadrupole Model/PQM/ in the framework of the Elliott‘s SU(3) Model with the aim to obtain the complementary and competing features of the two interactions through the relation between the pairing and the SU(3) bases. First, we establish a correspondence between the SO(8) pairing basis and the Elliott's SU(3) basis. It is derived from their complementarity to the same LST coupling chain of the shell-model number-conserving algebra. The probability distribution of the SU(3) basis states within the SO(8) pairing states is also obtained and allows the investigation of the interplay between the pairing and quadrupole interactions in the Hamiltonian of the PQM, containing both of them as limiting cases. The description of some realistic N∼Z nuclear systems is investigated in a SU(3)-symmetry-adapted basis within a model space of one and two oscillator shells.

  15. 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.

  16. Meridional Variations of C2H2 and C2H6 in Jupiter's Atmosphere from Cassini CIRS Infrared Spectra

    NASA Technical Reports Server (NTRS)

    Nixon, C. A.; Achterberg, R. K.; Conrath, B. J.; Irwin, P. G. J.; Fouchet, T.; Parrish, P. D.; Romani, P. N.; Abbas, M.; LeClair, A.; Strobel, D.

    2004-01-01

    Hydrocarbons such as acetylene (C2H2) and ethane (C2H6) are important tracers in Jupiter's atmosphere, constraining our models of the chemical and dynamical processes. However, our knowledge of the vertical and meridional variations of their abundances has remained sparse. During the flyby of the Cassini spacecraft in December 2000, the Composite Infrared Spectrometer (CIRS) instrument was used to map the spatial variation of emissions from 10-1400 cm(sup -1) (1000-7 microns). In this paper we analyze a zonally-averaged set of CIRS spectra taken at the highest (0.5 cm(sup -1)) resolution, to infer atmospheric temperatures in the stratosphere at 0.5-20 mbar via the v4 band of CH4, and in the troposphere at 150-400 mbar, via the H2 absorption at 600-800 cm(sup -1). Simultaneously, we retrieve the abundances of C2H2 and C2H6 via the v5 and vg bands respectively. Tropospheric absorption and stratospheric emission are highly anti-correlated at the CIRS resolution, introducing a non-uniqueness into the retrievals, such that vertical gradient and column abundance cannot both be found without additional constraints. Assuming profile gradients from photochemical calculations, we show that the column abundance of C2H2 decreases sharply towards the poles by a factor approximately 4, while C2H6 is unchanged in the north and increasing in the south, by a factor approximately 1.8. An explanation for the meridional trends is proposed in terms of a combination of photochemistry and dynamics. Poleward, the decreasing UV flux is predicted to decrease the abundances of C2H2 and C2H6 by factors 2.7 and 3.5 respectively at a latitude 70 deg. However, the lifetime of C2H6 in the stratosphere (5 x 10(exp 9)) is much longer than the dynamical timescale for meridional motions inferred from SL-9 debris (5 x 10(exp 8 s)), and therefore the constant or rising abundance towards high latitudes likely indicates that meridional mixing dominates over photochemical effects. For C2H2, the opposite

  17. 2H 2O quadrupolar splitting used to measure water exchange in erythrocytes

    NASA Astrophysics Data System (ADS)

    Kuchel, Philip W.; Naumann, Christoph

    2008-05-01

    The 2H NMR resonance from HDO (D = 2H) in human red blood cells (RBCs) suspended in gelatin that was held stretched in a special apparatus was distinct from the two signals that were symmetrically arranged on either side of it, which were assigned to extracellular HDO. The large extracellular splitting is due to the interaction of the electric quadrupole moment of the 2H nuclei with the electric field gradient tensor of the stretched, partially aligned gelatin. Lack of resolved splitting of the intracellular resonance indicated greatly diminished or absent ordering of the HDO inside RBCs. The separate resonances enabled the application of a saturation transfer method to estimate the rate constants of transmembrane exchange of water in RBCs. However both the theory and the practical applications needed modifications because even in the absence of RBCs the HDO resonances were maximally suppressed when the saturating radio-frequency radiation was applied exactly at the central frequency between the two resonances of the quadrupolar HDO doublet. More statistically robust estimates of the exchange rate constants were obtained by applying two-dimensional exchange spectroscopy (2D EXSY), with back-transformation analysis. A monotonic dependence of the estimates of the efflux rate constants on the mixing time, tmix, used in the 2D EXSY experiment were seen. Extrapolation to tmix = 0, gave an estimate of the efflux rate constant at 15 °C of 31.5 ± 2.2 s -1 while at 25 °C it was ˜50 s -1. These values are close to, but less than, those estimated by an NMR relaxation-enhancement method that uses Mn 2+ doping of the extracellular medium. The basis for this difference is thought to include the high viscosity of the extracellular gel. At the abstract level of quantum mechanics we have used the quadrupolar Hamiltonian to provide chemical shift separation between signals from spin populations across cell membranes; this is the first time, to our knowledge, that this has been

  18. Electric quadrupole excitations in relativistic nucleus-nucleus collisions

    NASA Technical Reports Server (NTRS)

    Norbury, John W.

    1989-01-01

    Calculations are presented for electric quadrupole excitations in relativistic nucleus-nucleus collisions. The theoretical results are compared to an extensive data set and it is found that electric quadrupole effects provide substantial corrections to cross sections, especially for heavier nuclei.

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

    DOEpatents

    Maschke, Alfred W.

    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.

  20. 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.

  1. 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.

  2. Critical fluctuations in DOPC/DPPC-d62/cholesterol mixtures: 2H magnetic resonance and relaxation.

    PubMed

    Davis, James H; Ziani, Latifa; Schmidt, Miranda L

    2013-07-28

    Static and magic angle spinning (MAS) (2)H nuclear magnetic resonance experiments have been performed on a series of multilamellar dispersions of di-oleoyl-sn-glycero-3-phosphocholine/di-palmitoyl-sn-glycero-3-phosphocholine-d62/cholesterol in water to investigate the compositional fluctuations which occur in the region of the line of critical points for this ternary system. The strong dependence of the MAS line widths on temperature, sample composition, and spinning rate provides a direct measure of the magnitude of the fluctuations in the (2)H quadrupolar Hamiltonian. These data are analyzed in terms of models for critical fluctuations in composition leading to a value for the critical index for the correlation length, ν(c) = 0.628, consistent with a three dimensional Ising model. PMID:23902029

  3. 2H-DNP-enhanced 2H–13C solid-state NMR correlation spectroscopy

    PubMed Central

    Maly, Thorsten; Andreas, Loren B.; Smith, Albert A.

    2015-01-01

    Perdeuteration of biological macromolecules for magic angle spinning solid-state NMR spectroscopy can yield high-resolution 2H–13C correlation spectra and the method is therefore of great interest for the structural biology community. Here we demonstrate that the combination of sample deuteration and dynamic nuclear polarization yields resolved 2H–13C correlation spectra with a signal enhancement of ε ≥ 700 compared to a spectrum recorded with microwaves off and otherwise identical conditions. To our knowledge, this is the first time that 2H-DNP has been employed to enhance MAS-NMR spectra of a biologically relevant system. The DNP process is studied using several polarizing agents and the technique is applied to obtain 2H–13C correlation spectra of U-[2H, 13C] proline. PMID:20458422

  4. 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

  5. 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.

  6. 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.

  7. 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.

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

    SciTech Connect

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

    2007-09-15

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

  9. Atomic Quadrupole Moment Measurement Using Dynamic Decoupling.

    PubMed

    Shaniv, R; Akerman, N; Ozeri, R

    2016-04-01

    We present a method that uses dynamic decoupling of a multilevel quantum probe to distinguish small frequency shifts that depend on m_{j}^{2}, where m_{j}^{2} is the angular momentum of level |j⟩ along the quantization axis, from large noisy shifts that are linear in m_{j}, such as those due to magnetic field noise. Using this method we measured the electric-quadrupole moment of the 4D_{5/2} level in ^{88}Sr^{+} to be 2.973_{-0.033}^{+0.026}ea_{0}^{2}. Our measurement improves the uncertainty of this value by an order of magnitude and thus helps mitigate an important systematic uncertainty in ^{88}Sr^{+} based optical atomic clocks and verifies complicated many-body quantum calculations. PMID:27104691

  10. Development of a quadrupole resonance confirmation system

    NASA Astrophysics Data System (ADS)

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

    2004-09-01

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

  11. 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.

  12. 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.

  13. Nonzero Quadrupole Moments of Candidate Tetrahedral Bands

    SciTech Connect

    Bark, R. A.; Lawrie, E. A.; Lawrie, J. J.; Mullins, S. M.; Murray, S. H. T.; Ncapayi, N. J.; Smit, F. D.; Sharpey-Schafer, J. F.; Lindsay, R.

    2010-01-15

    Negative-parity bands in the vicinity of {sup 156}Gd and {sup 160}Yb have been suggested as candidates for the rotation of tetrahedral nuclei. We report the observation of the odd and even-spin members of the lowest energy negative-parity bands in {sup 160}Yb and {sup 154}Gd. The properties of these bands are similar to the proposed tetrahedral band of {sup 156}Gd and its even-spin partner. Band-mixing calculations are performed and absolute and relative quadrupole moments deduced for {sup 160}Yb and {sup 154}Gd. The values are inconsistent with zero, as required for tetrahedral shape, and the bands are interpreted as octupole vibrational bands. The failure to observe the in-band E2 transitions of the bands at low spins can be understood using the measured B(E1) and B(E2) values.

  14. Atomic Quadrupole Moment Measurement Using Dynamic Decoupling

    NASA Astrophysics Data System (ADS)

    Shaniv, R.; Akerman, N.; Ozeri, R.

    2016-04-01

    We present a method that uses dynamic decoupling of a multilevel quantum probe to distinguish small frequency shifts that depend on mj2, where mj2 is the angular momentum of level |j ⟩ along the quantization axis, from large noisy shifts that are linear in mj, such as those due to magnetic field noise. Using this method we measured the electric-quadrupole moment of the 4 D5 /2 level in 88Sr+ to be 2.97 3-0.033+0.026e a02 . Our measurement improves the uncertainty of this value by an order of magnitude and thus helps mitigate an important systematic uncertainty in 88Sr+ based optical atomic clocks and verifies complicated many-body quantum calculations.

  15. 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.

  16. Radio-frequency quadrupole linear accelerator

    SciTech Connect

    Wangler, T.P.; Stokes, R.H.

    1980-01-01

    The radio-frequency quadrupole (RFQ) is a new linear accelerator concept in which rf electric fields are used to focus, bunch, and accelerate the beam. Because the RFQ can provide strong focusing at low velocities, it can capture a high-current dc ion beam from a low-voltage source and accelerate it to an energy of 1 MeV/nucleon within a distance of a few meters. A recent experimental test at the Los Alamos Scientific Laboratory (LASL) has confirmed the expected performance of this structure and has stimulated interest in a wide variety of applications. The general properties of the RFQ are reviewed and examples of applications of this new accelerator are presented.

  17. 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.

  18. Meridional Variations of C2H2 and C2H6 in Jupiter's Atmosphere from Cassini CIRS Infrared Spectra

    NASA Technical Reports Server (NTRS)

    Nixon, C. A.; Achterberg, R. K.; Conrath, B. J.; Irwin, P. G. J.; Fouchet, T.; Parrish, P. D.; Abbas, M.; LeClaire, A.; Romani, P. N.; Simon-Miller, A. A.

    2004-01-01

    The abundances of hydrocarbons such as acetylene (C2H2) and ethane (C2H6) in Jupiter's atmosphere are important physical quantities, constraining our models of the chemical and dynamical processes. However, our knowledge of these quantities and their vertical and latitudinal variations has remained sparse. The flyby of the Cassini spacecraft with Jupiter at the end of 2000 provided an excellent opportunity to observe the infrared spectrum with the Composite Infrared Spectrometer (CIRS) instrument, mapping the spatial variation of emissions from 10-1400 cm-1. CIRS spectra taken at the highest resolution (0.5 cm-1) in early December 2000 have been analysed to infer atmospheric temperatures in the stratosphere at 0.5-20 mbar via the v4 of CH4, and in the troposphere at 100-400 mbar, via the hydrogen collision-induced continuum absorption at 600-800 cm. Simultaneously, we have searched for meridional abundance variations in C2H2 and C2H6 via the v5 and vg bands respectively. Tropospheric absorption and stratospheric emission are highly anti-correlated at the CIM resolution, introducing a non-uniqueness into the retrievals, which means that vertical gradient and column abundance cannot be simultaneously found without additional constraints. If we assume the profile shapes from photochemical model calculations, we show that the column abundance of C2H2 must decrease sharply towards the poles, while C2H6 is constant or slightly increasing. The relevance of these results to current photochemical and dynamical knowledge of Jupiter's atmosphere is discussed.

  19. Evaluation of an electrochemical N2/H2 gas separator

    NASA Technical Reports Server (NTRS)

    Marshall, R. D.; Wynveen, R. A.; Carlson, J. N.

    1973-01-01

    A program was successfully completed to evaluate an electrochemical nitrogen/hydrogen (N2/H2) separator for use in a spacecraft nitrogen (N2) generator. Based on the technical data obtained a N2/H2 separator subsystem consisting of an organic polymer gas permeator first stage and an electrochemical second and third stage was estimated to have the lowest total spared equivalent weight, 257 kg (566 lb), for a 15 lb/day N2 generation rate. A pre-design analysis of the electrochemical N2/H2 separator revealed that its use as a first stage resulted in too high a power requirement to be competitive with the organic polymer membrane and the palladium-silver membrane separation methods. As a result, program emphasis was placed on evaluating the electrochemical. A parametric test program characterized cell performance and established second- and third-stage electrochemical N2/H2 separator operating conditions. A design verification test was completed on the second and third stages. The second stage was then successfully endurance tested for 200 hours.

  20. The distribution and abundance of interstellar C2H

    NASA Technical Reports Server (NTRS)

    Huggins, P. J.; Carlson, W. J.; Kinney, A. L.

    1984-01-01

    C2H(N = 1-0) emission has been extensively observed in a variety of molecular clouds, including: 12 hot, dense, cloud cores, 3 bright-rimmed clouds (in NGC 1977, IC 1396, and IC 1848), and across the extended OMC - 1 cloud. It has also been observed in the circumstellar envelopes IRC + 10216 and AFGL 2688. Abundance analyses of the molecular clouds yield C2H/(C-13)O abundance ratios of about 0.01, with little variation (less than about a factor of 4) either between clouds or across individual clouds. In the Orion plateau source, the C2H abundance is enhanced by less than a factor of 4, relative to the extended cloud. The generally high levels of C2H found in the molecular clouds are not readily accounted for by simple, steady-state chemical models, and suggest, as do earlier observations of atomic carbon, that the carbon chemistry in dense clouds is more active than is commonly assumed.

  1. 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.

  2. Conformation-Specific Infrared Spectroscopy of γ2-PEPTIDE Foldamers: Ac-γ2-hPhe-γ2-hAla-NHMe and Ac-γ2-hAla-γ2-hPhe-NHMe

    NASA Astrophysics Data System (ADS)

    James, William H., III; Buchanan, Evan G.; Müller, Christian W.; Zwier, Timothy S.; Guo, Li; Gellman, Samuel H.

    2010-06-01

    IR/UV double-resonance spectroscopy has been used to study the intrinsic conformational preferences of naturally occurring and synthetic peptides. These studies demonstrated the power of double-resonance methods and highlighted the ability of even short peptide mimics to form a variety of intramolecular hydrogen bonded architectures. Currently, we are extending these studies to a series of model γ2-peptides, which differ from α-peptides by virtue of having two additional, substitutable methylene units separating amide groups in the peptide backbone. Initial studies centered on the conformation-specific infrared spectra of Ac-γ2-hPhe-NHMe, where three unique conformational isomers (two hydrogen-bonded and one intramolecular amide stacked) were observed under the isolated-molecule conditions of a jet-cooled environment. This talk will focus on on two larger γ2-peptides, Ac-γ2-hPhe-γ2-hAla-NHMe and Ac-γ2-hAla-γ2-hPhe-NHMe. Utilizing resonant ion-dip infrared spectroscopy, the single-conformation infrared spectra of eight resolved conformers of the two molecules were recorded in the amide NH stretch region. The resulting infrared spectra of the tri-amides contain evidence for structures comprised of one, two, and three intramolecular amide-amide hydrogen bonds, the last of which is unprecedented for a tri-amide. In an effort to make firm conformational assignments, the spectroscopic data will be compared to the results of harmonic vibrational frequency calculations using traditional DFT and dispersion-corrected DFT methods, the results of which will be discussed.

  3. Direct analysis of [6,6-(2)H2]glucose and [U-(13)C6]glucose dry blood spot enrichments by LC-MS/MS.

    PubMed

    Coelho, Margarida; Mendes, Vera M; Lima, Inês S; Martins, Fátima O; Fernandes, Ana B; Macedo, M Paula; Jones, John G; Manadas, Bruno

    2016-06-01

    A liquid chromatography tandem mass spectrometry (LC-MS/MS) using multiple reaction monitoring (MRM) in a triple-quadrupole scan mode was developed and comprehensively validated for the determination of [6,6-(2)H2]glucose and [U-(13)C6]glucose enrichments from dried blood spots (DBS) without prior derivatization. The method is demonstrated with dried blood spots obtained from rats administered with a primed-constant infusion of [U-(13)C6]glucose and an oral glucose load enriched with [6,6-(2)H2]glucose. The sensitivity is sufficient for analysis of the equivalent to <5μL of blood and the overall method was accurate and precise for the determination of DBS isotopic enrichments. PMID:27107853

  4. Measurement of the electric quadrupole moment of CO

    NASA Astrophysics Data System (ADS)

    Chetty, Naven; Couling, Vincent W.

    2011-04-01

    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 Θ = (-8.77 ± 0.31) × 10-40 C m2 and a hyperpolarizability term of b' = (-0.1243 ± 0.0078) × 10-60 C3 m4 J-2. For dipolar molecules, the quadrupole moment is origin dependent, and the value reported here is referred to an origin called the effective quadrupole center. Comparison of this value with the center-of-mass quadrupole moment obtained from other experiments yields information about the dynamic dipole-quadrupole and dipole-magnetic dipole polarizabilities. The temperature-independent term, which contributes (7.0 ± 0.6)% to the EFGIB at room temperature, is by no means insignificant, and must necessarily be accounted for if the quadrupole moment is to be definitively established. The measured Θ and b' are compared with the best available ab initio calculated values.

  5. Measurement of the electric quadrupole moment of N2O

    NASA Astrophysics Data System (ADS)

    Chetty, Naven; Couling, Vincent W.

    2011-04-01

    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 Θ = (-11.03 ± 0.41) × 10-40 C m2, and a hyperpolarizability term of b = (-0.638 ± 0.063) × 10-60 C3 m4 J-2. For dipolar molecules, the quadrupole moment is origin dependent, and the value reported here is referred to an origin called the effective quadrupole center (EQC). Comparison of this value with the center of mass (CM) quadrupole moment obtained from MBER experiments yields information about the dynamic dipole-quadrupole and dipole-magnetic dipole polarizabilities. The temperature-independent term, previously assumed to contribute negligibly to the EFGIB, is found to contribute some (5.2 ± 0.6)% to the effect at room temperature and clearly needs to be accounted for if the quadrupole moment is to be definitively established.

  6. Search for the isomers of C2H3NO and C2H3NS in the Interstellar Medium

    NASA Astrophysics Data System (ADS)

    Etim, Emmanuel; Chakrabarti, Sandip Kumar; Das, Ankan; Gorai, Prasanta; Arunan, Elangannan

    2016-07-01

    With about 40% of all the known interstellar and circumstellar molecules having their isomeric analogues as known astromolecules, isomerism remains one of the leading themes in interstellar chemistry. In this regard, the recent detection of methyl isocyanate (with a number of isomeric analogues) in the Sgr B2(N) giant molecular cloud opens a new window for the possible astronomical detection of other C_2H_3NO isomers. The present work looks at the possibility of detecting other isomers of methyl isocyanate by considering different factors such as thermodynamic stability of the different isomers with respect to the Energy, Stability and Abundance (ESA) relationship, effect of interstellar hydrogen bonding with respect to the formation these isomers on the surface of the interstellar dust grains, possible formation routes for these isomers, spectroscopic parameters for potential astromolecules among these isomers, chemical modeling among other studies. The same studies are repeated for the C_2H_3NS isomers which are the isoelectroninc analogues of the C_2H_3NO isomers taking into account the unique chemistry of S and O-containing interstellar molecular species. Among the C_2H_3NS isomers, methyl isothiocyanate remains the most potential candidate for astronomical observation.

  7. The infrared spectra of C2H4(+) and C2H3 trapped in solid neon.

    PubMed

    Jacox, Marilyn E; Thompson, Warren E

    2011-02-14

    When a mixture of ethylene in a large excess of neon is codeposited at 4.3 K with a beam of neon atoms that have been excited in a microwave discharge, two groups of product absorptions appear in the infrared spectrum of the deposit. Similar studies using C(2)H(4)-1-(13)C and C(2)D(4) aid in product identification. The first group of absorptions arises from a cation product which possesses two identical carbon atoms, giving the first infrared identification of two fundamentals of C(2)H(4)(+) and three of C(2)D(4)(+), as well as a tentative identification of ν(9) of C(2)H(4)(+). The positions of these absorptions are consistent with the results of density functional calculations and of earlier photoelectron studies. All of the members of the second group of product absorptions possess two inequivalent carbon atoms. They are assigned to the vinyl radical, C(2)H(3), and to C(2)D(3), in agreement with other recent infrared assignments for those species. PMID:21322694

  8. Observations of CH4, C2H6, and C2H2 in the stratosphere of Jupiter.

    PubMed

    Sada, P V; Bjoraker, G L; Jennings, D E; McCabe, G H; Romani, P N

    1998-12-01

    We have performed high-resolution spectral observations at mid-infrared wavelengths of CH4 (8.14 micrometers), C2H6 (12.16 micrometers), and C2H2 (13.45 micrometers) on Jupiter. These emission features probe the stratosphere of the planet and provide information on the carbon-based photochemical processes taking place in that region of the atmosphere. The observations were performed using our cryogenic echelle spectrometer CELESTE, in conjunction with the McMath-Pierce 1.5-m solar telescope between November 1994 and February 1995. We used the methane observations to derive the temperature profile of the jovian atmosphere in the 1-10 mbar region of the stratosphere. This profile was then used in conjunction with height-dependent mixing ratios of each hydrocarbon to determine global abundances for ethane and acetylene. The resulting mixing ratios are 3.9(+1.9)(-1.3) x 10(-6) for C2H6 (5 mbar pressure level), and 2.3 +/- 0.5 x 10(-8) for C2H2 (8 mbar pressure level), where the quoted uncertainties are derived from model variations in the temperature profile which match the methane observation uncertainties. PMID:11878354

  9. 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.

  10. High-Efficiency Resonant Cavity Quadrupole Moment Monitor

    SciTech Connect

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

    2007-04-13

    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.

  11. Time-resolved measurement of quadrupole wakefields in corrugated structures

    NASA Astrophysics Data System (ADS)

    Lu, Chao; Fu, Feichao; Jiang, Tao; Liu, Shengguang; Shi, Libin; Wang, Rui; Zhao, Lingrong; Zhu, Pengfei; Zhang, Zhen; Xiang, Dao

    2016-02-01

    Corrugated structures have recently been widely used for manipulating electron beam longitudinal phase space and for producing THz radiation. Here we report on time-resolved measurements of the quadrupole wakefields in planar corrugated structures. It is shown that while the time-dependent quadrupole wakefield produced by a planar corrugated structure causes significant growth in beam transverse emittance, it can be effectively canceled with a second corrugated structure with orthogonal orientation. The strengths of the time-dependent quadrupole wakefields for various corrugated structure gaps are also measured and found to be in good agreement with theories. Our work should forward the applications of corrugated structures in many accelerator based scientific facilities.

  12. Development of Superconducting Focusing Quadrupoles for Heavy Ion Drivers

    SciTech Connect

    Martovetsky, N; Manahan, R; Lietzke, A F

    2001-09-10

    Heavy Ion Fusion (HIF) is exploring a promising path to a practical inertial-confinement fusion reactor. The associated heavy ion driver will require a large number of focusing quadrupole magnets. A concept for a superconducting quadrupole array, using many simple racetrack coils, was developed at LLNL. Two, single-bore quadrupole prototypes of the same design, with distinctly different conductor, were designed, built, and tested. Both prototypes reached their short sample currents with little or no training. Magnet design, and test results, are presented and discussed.

  13. Hydration and Lateral Organization in Phospholipid Bilayers Containing Sphingomyelin: A 2H-NMR Study

    PubMed Central

    Steinbauer, Bernhard; Mehnert, Thomas; Beyer, Klaus

    2003-01-01

    Interfacial properties of lipid bilayers were studied by 2H nuclear magnetic resonance spectroscopy, with emphasis on a comparison between phosphatidylcholine and sphingomyelin. Spectral resolution and sensitivity was improved by macroscopic membrane alignment. The motionally averaged quadrupolar interaction of interlamellar deuterium oxide was employed to probe the interfacial polarity of the membranes. The D2O quadrupolar splittings indicated that the sphingomyelin lipid-water interface is less polar above the phase transition temperature Tm than below Tm. The opposite behavior was found in phosphatidylcholine bilayers. Macroscopically aligned sphingomyelin bilayers also furnished 2H-signals from the amide residue and from the hydroxyl group of the sphingosine moiety. The rate of water-hydroxyl deuteron exchange could be measured, whereas the exchange of the amide deuteron was too slow for the inversion-transfer technique employed, suggesting that the amide residue is involved in intermolecular hydrogen bonding. Order parameter profiles in mixtures of sphingomyelin and chain-perdeuterated phosphatidylcholine revealed an ordering effect as a result of the highly saturated chains of the sphingolipids. The temperature dependence of the 2H quadrupolar splittings was indicative of lateral phase separation in the mixed systems. The results are discussed with regard to interfacial structure and lateral organization in sphingomyelin-containing biomembranes. PMID:12885648

  14. Refractive index and birefringence of 2H silicon carbide

    NASA Technical Reports Server (NTRS)

    Powell, J. A.

    1972-01-01

    The refractive indices of 2H SiC were measured over the wavelength range 435.8 to 650.9 nm by the method of minimum deviation. At the wavelength lambda = 546.1 nm, the ordinary index n sub 0 was 2.6480 and the extraordinary index n sub e was 2.7237. The estimated error (standard deviation) in the measured values is 0.0006 for n sub 0 and 0.0009 for n sub e. The experimental data were curve fitted to the Cauchy equation for the index of refraction as a function of wavelength. The birefringence of 2H SiC was found to vary from 0.0719 at lambda = 650.9 nm to 0.0846 at lambda = 435.8 nm.

  15. Lattice Instability of 2H-TaSe2

    NASA Astrophysics Data System (ADS)

    John Bosco Balaguru, R.; Lawrence, N.; Alfred Cecil Raj, S.

    The charge density wave (CDW) in the layered compound 2H-TaSe2 at low temperatures has a commensurate phase, which causes super lattice points to appear in the Brillöuin zone of the undistorted phase. A Born-von Karman formalism has been employed for the calculation of phonon frequency distribution curves of 2H-TaSe2 both in the normal and in the commensurate charge density wave (CCDW) phases. A folding technique has been adopted for the calculation in the CCDW phase. The phonon distribution for both the phases have been reported. With these distributions the thermal properties such as specific heat capacity, Debye Waller factor W(k) and thermal conductivity have been worked out, and compared with the available experimental results.

  16. C(2)H(4) metabolism in morning glory flowers.

    PubMed

    Beyer, E M; Sundin, O

    1978-06-01

    Flowers of Ipomoea tricolor Cav. (cv. Heavenly Blue) were cut at various stages of development and evaluated for their ability to metabolize ethylene. Freshly cut buds or flowers were treated in glass containers for 8 hours with 6 mul/liter of highly purified (14)C(2)H(4). Following removal of dissolved (14)C(2)H(4), radioactivity was determined for the different flower tissues and trappd CO(2). (14)C(2)H(4) oxidation to (14)CO(2) and tissue incorporation occurred at very low to nondetectable levels 2 to 3 days prior to flower opening. About 1 day prior to full bloom, just at the time when mature buds become responsive to ethylene (Kende and Hanson, Plant Physiol 1976, 57: 523-527), there was a dramatic increase in the capacity of the buds to oxidize (14)C(2)H(4) to (14)CO(2). This activity continued to increase until the flower was fully opened reaching a peak activity of 2,500 dpm per three flowers per 8 hours. It then declined as the flower closed and rapidly senesced. A similar but smaller peak occurred in tissue incorporation and it was followed by a second peak during late flower senescence. This first peak in tissue incorporation and the dramatic peak in ethylene oxidation slightly preceded a large peak of natural ethylene production which accompanied flower senescence. The ethylene metabolism observed was clearly dependent on cellular metabolism and did not involve microorganisms since heat killing destroyed this activity and badly contaminated heat-killed flowers were unable to metabolize ethylene. PMID:16660421

  17. Charge transfer in energetic Li^2+ - H collisions

    NASA Astrophysics Data System (ADS)

    Mancev, I.

    2008-07-01

    The total cross sections for charge transfer in Li^2+ - H collisions have been calculated, using the four-body first Born approximation with correct boundary conditions (CB1-4B) and four-body continuum distorted wave method (CDW-4B) in the energy range 10 - 5000 keV/amu. Present results call for additional experimental data at higher impact energies than presently available.

  18. 2H Evaporator CP class instrumentation uncertainties evaluations

    SciTech Connect

    Hwang, E.

    1994-02-10

    The Evaporator Pot Temperature Instrumentations and the Steam Condensate Gamma Monitors are two instrumentation systems in the 2H Evaporator facilities that are classified as the critical protection. The temperature high alarm and interlock circuit and the temperature recorder circuit of the pot temperature instrumentation loop are described. From the gamma monitor loop, the high gamma alarm and interlock circuit, failure alarm and interlock circuit, cesium activity recorder circuit, and americium activity recorder circuit are described. (GHH)

  19. Core-mass nonadiabatic corrections to molecules: H2, H2+, and isotopologues.

    PubMed

    Diniz, Leonardo G; Alijah, Alexander; Mohallem, José Rachid

    2012-10-28

    For high-precision calculations of rovibrational states of light molecules, it is essential to include non-adiabatic corrections. In the absence of crossings of potential energy surfaces, they can be incorporated in a single surface picture through coordinate-dependent vibrational and rotational reduced masses. We present a compact method for their evaluation and relate in particular the vibrational mass to a well defined nuclear core mass derived from a Mulliken analysis of the electronic density. For the rotational mass we propose a simple, but very effective parametrization. The use of these masses in the nuclear Schrödinger equation yields numerical data for the corrections of a much higher quality than can be obtained with optimized constant masses, typically better than 0.1 cm(-1). We demonstrate the method for H(2), H(2)(+), and singly deuterated isotopologues. Isotopic asymmetry does not present any particular difficulty. Generalization to polyatomic molecules is straightforward. PMID:23126719

  20. 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.

  1. 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.

  2. Autonomously Calibrating a Quadrupole Mass Spectrometer

    NASA Technical Reports Server (NTRS)

    Lee, Seungwon; Bornstein, Benjamin J.

    2009-01-01

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

  3. Quadrupole resonance spectroscopic study of narcotic materials

    NASA Astrophysics Data System (ADS)

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

    1997-02-01

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

  4. Fano quadrupole in a nanoscale ring

    NASA Astrophysics Data System (ADS)

    Satanin, Arkady; Klimeck, Gerhard

    2005-03-01

    In solid state systems such as Aharonov-Bohm (AB) rings, two-dimensional electronic waveguides, and barriers, interference of a localized wave with propagating states produces Fano resonances in the conductance. The scattering amplitude near a Fano zero-pole pair behaves like the amplitude of a dipole when the pole and the zero play the roles of a particle and an antiparticle, respectively [1]. This separate Fano-dipole has been already observed in the AB ring with an embedded quantum dot (QD) [2]. In the present work, we examine new effects on the collision of Fano dipoles and its manifestation in the transmission. The numerical results for a realistic AB ring with two embedded QD's will be presented. We show that the two Fano-dipoles form a new quasi-particle, which behaves as a coupled object -- the Fano quadrupole. This property gives an additional possibility of manipulating transmission resonances (a collapse of particle and hole) in a nanoscale ring by changing the parameters of the system. We discuss an analogy of Fano collision in an AB ring and a γ-X barrier [3]. [1] Z. Shao et al., PRB 49, 7453 (1994). [2] K. Kobayashi, et al. PRL, 85, 256806 (2002). [3] R. C. Bowen, et al. PRB 52, 2754 (1995).

  5. Measurement of regional cerebral blood flow in cat brain using intracarotid 2H2O and 2H NMR imaging

    SciTech Connect

    Detre, J.A.; Subramanian, V.H.; Mitchell, M.D.; Smith, D.S.; Kobayashi, A.; Zaman, A.; Leigh, J.S. Jr. )

    1990-05-01

    Cerebral blood flow (CBF) was measured in cat brain in vivo at 2.7 T using 2H NMR to monitor the washout of deuterated saline injected into both carotid arteries via the lingual arteries. In anesthetized cats, global CBF varied directly with PaCO{sub 2} over a range of 20-50 mm Hg, and the corresponding global CBF values ranged from 25 to 125 ml.100 g-1.min-1. Regional CBF was measured in a 1-cm axial section of cat brain using intracarotid deuterated saline and gradient-echo 2H NMR imaging. Blood flow images with a maximum pixel resolution of 0.3 x 0.3 x 1.0 cm were generated from the deuterium signal washout at each pixel. Image derived values for CBF agreed well with other determinations, and decreased significantly with hypocapnia.

  6. Ellipsoidal universe can solve the cosmic microwave background quadrupole problem.

    PubMed

    Campanelli, L; Cea, P; Tedesco, L

    2006-09-29

    The recent 3 yr Wilkinson Microwave Anisotropy Probe data have confirmed the anomaly concerning the low quadrupole amplitude compared to the best-fit Lambda-cold dark matter prediction. We show that by allowing the large-scale spatial geometry of our universe to be plane symmetric with eccentricity at decoupling or order 10(-2), the quadrupole amplitude can be drastically reduced without affecting higher multipoles of the angular power spectrum of the temperature anisotropy. PMID:17026023

  7. Application of the Thermal Quadrupoles Method to Semitransparent Solids

    NASA Astrophysics Data System (ADS)

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

    2012-11-01

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

  8. CO2/H(+) sensing: peripheral and central chemoreception.

    PubMed

    Lahiri, Sukhamay; Forster, Robert E

    2003-10-01

    H(+) is maintained constant in the internal environment at a given body temperature independent of external environment according to Bernard's principle of "milieu interieur". But CO2 relates to ventilation and H(+) to kidney. Hence, the title of the chapter. In order to do this, sensors for H(+) in the internal environment are needed. The sensor-receptor is CO2/H(+) sensing. The sensor-receptor is coupled to integrate and to maintain the body's chemical environment at equilibrium. This chapter dwells on this theme of constancy of H(+) of the blood and of the other internal environments. [H(+)] is regulated jointly by respiratory and renal systems. The respiratory response to [H(+)] originates from the activities of two groups of chemoreceptors in two separate body fluid compartments: (A) carotid and aortic bodies which sense arterial P(O2) and H(+); and (B) the medullary H(+) receptors on the ventrolateral medulla of the central nervous system (CNS). The arterial chemoreceptors function to maintain arterial P(O2) and H(+) constant, and medullary H(+) receptors to maintain H(+) of the brain fluid constant. Any acute change of H(+) in these compartments is taken care of almost instantly by pulmonary ventilation, and slowly by the kidney. This general theme is considered in Section 1. The general principles involving cellular CO2 reactions mediated by carbonic anhydrase (CA), transport of CO2 and H(+) are described in Section 2. Since the rest of the chapter is dependent on these key mechanisms, they are given in detail, including the role of Jacobs-Stewart Cycle and its interaction with carbonic anhydrase. Also, this section deals briefly with the mechanisms of membrane depolarization of the chemoreceptor cells because this is one mechanism on which the responses depend. The metabolic impact of endogenous CO2 appears in the section with a historical twist, in the context of acclimatization to high altitude (Section 3). Because low P(O2) at high altitude stimulates

  9. 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.

  10. Theoretical kinetics of O + C2H4

    DOE PAGESBeta

    Li, Xiaohu; Jasper, Ahren W.; Zádor, Judit; Miller, James A.; Klippenstein, Stephen J.

    2016-06-01

    The reaction of atomic oxygen with ethylene is a fundamental oxidation step in combustion and is prototypical of reactions in which oxygen adds to double bonds. For 3O+C2H4 and for this class of reactions generally, decomposition of the initial adduct via spin-allowed reaction channels on the triplet surface competes with intersystem crossing (ISC) and a set of spin-forbidden reaction channels on the ground-state singlet surface. The two surfaces share some bimolecular products but feature different intermediates, pathways, and transition states. In addition, the overall product branching is therefore a sensitive function of the ISC rate. The 3O+C2H4 reaction has beenmore » extensively studied, but previous experimental work has not provided detailed branching information at elevated temperatures, while previous theoretical studies have employed empirical treatments of ISC. Here we predict the kinetics of 3O+C2H4 using an ab initio transition state theory based master equation (AITSTME) approach that includes an a priori description of ISC. Specifically, the ISC rate is calculated using Landau–Zener statistical theory, consideration of the four lowest-energy electronic states, and a direct classical trajectory study of the product branching immediately after ISC. The present theoretical results are largely in good agreement with existing low-temperature experimental kinetics and molecular beam studies. Good agreement is also found with past theoretical work, with the notable exception of the predicted product branching at elevated temperatures. Above ~1000 K, we predict CH2CHO+H and CH2+CH2O as the major products, which differs from the room temperature preference for CH3+HCO (which is assumed to remain at higher temperatures in some models) and from the prediction of a previous detailed master equation study.« less

  11. Rotational spectroscopy of 2H,3H-perfluoropentane

    NASA Astrophysics Data System (ADS)

    Duong, Chinh H.; Obenchain, Daniel A.; Cooke, S. A.; Novick, Stewart E.

    2016-06-01

    The structure of 2H,3H-perfluoropentane, CF3CHFCHFCF2CF3, has been determine by a combination of Chirp-pulsed Fourier transform microwave (CP-FTMW) spectroscopy and cavity FTMW spectroscopy. Of the four possible stereoisomers, only the enantiomeric pair (R,R)/(S,S) were observed experimentally; there was no spectroscopic evidence for the enantiomeric pair (R,S)/(S,R). The conformeric structure of the (R,R)/(S,S) stereoisomer(s) was that of partial helices with C-C-C-C dihedral angles of 12° (helical) and 1° (staggered).

  12. Synthesis Of 2h- And 13c-Substituted Dithanes

    DOEpatents

    Martinez, Rodolfo A.; Alvarez, Marc A.; Silks, III, Louis A.; Unkefer, Clifford J.

    2004-05-04

    The present invention is directed to labeled compounds, [2-.sup.13 C]dithane wherein the .sup.13 C atom is directly bonded to one or two deuterium atoms. The present invention is also directed to processes of preparing [2-.sup.13 C]dithane wherein the .sup.13 C atom is directly bonded to one or two deuterium atoms. The present invention is also directed to labeled compounds, e.g., [.sup.2 H.sub.1-2, .sup.13 C]methanol (arylthio)-, acetates wherein the .sup.13 C atom is directly bonded to exactly one or two deuterium atoms.

  13. Synthesis of 2H- and 13C-substituted dithanes

    DOEpatents

    Martinez, Rodolfo A.; Alvarez, Marc A.; Silks, III, Louis A.; Unkefer, Clifford J.

    2003-01-01

    The present invention is directed to labeled compounds, [2-.sup.13 C]dithiane wherein the .sup.13 C atom is directly bonded to one or two deuterium atoms. The present invention is also directed to processes of preparing [2-.sup.13 C]dithiane wherein the .sup.13 C atom is directly bonded to one or two deuterium atoms. The present invention is also directed to labeled compounds, e.g., [.sup.2 H.sub.1-2, .sup.13 C]methanol (arylthio)-, acetates wherein the .sup.13 C atom is directly bonded to exactly one or two deuterium atoms.

  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 π mm mrad and the fraction of He+ is about 99%.

  15. A microporous six-fold interpenetrated hydrogen-bonded organic framework for highly selective separation of C2H4/C2H6.

    PubMed

    Li, Peng; He, Yabing; Arman, Hadi D; Krishna, Rajamani; Wang, Hailong; Weng, Linhong; Chen, Banglin

    2014-11-01

    A unique six-fold interpenetrated hydrogen-bonded organic framework (HOF) has been developed, for the first time, for highly selective separation of C2H4/C2H6 at room temperature and normal pressure. PMID:25223376

  16. B2H6 PLAD Doped PMOS Device Performance

    SciTech Connect

    Fang, Z.; Miller, T.; Winder, E.; Persing, H.; Arevalo, E.; Gupta, A.; Parrill, T.; Singh, V.; Qin, S.; McTeer, A.

    2006-11-13

    Plasma doping (PLAD) achieves high wafer throughput by directly extracting ions across the plasma sheath. PLAD profiles are typically surface peaked instead of retrograde as obtained from beamline (BL) implant. It may require optimization of PLAD energy and dose in order to match BL doping results. From device optimization point of view, it is necessary to understand the impact of doping parameters to device characteristics. In this paper we present the PMOS device performance with the poly gate and source drain (SD) implants carried out using B2H6 PLAD. The BL control conditions are 2-5 keV 11B+ 4-6x1015 cm-2. Equivalent device performance for p+ poly gate doping is obtained using PLAD with B2H6 / H2. In SD doping using same gas mixture, nearly 50% reduction in SD contact resistance is observed in the PLAD splits. The reduction in SD contact resistance leads to 10-15% increase in device on-current, hence demonstrating the process advantages of using PLAD in addition to having a high wafer throughput.

  17. 241Am and 243Am charge distributions from muonic x-ray spectroscopy and the quadrupole moment of the 240Am fission isomer

    NASA Astrophysics Data System (ADS)

    Johnson, M. W.; Shera, E. B.; Hoehn, M. V.; Naumann, R. A.; Zumbro, J. D.; Bemis, C. E.

    1985-10-01

    The muonic K, L, and M X-ray spectra from 241Am and 243Am have been investigated. Analysis of these spectra yields intrinsic nuclear quadrupole moments [Q0241 = 12.16(15) e b and Q0243 = 12.10(17) e b] and Barrett radii. By combining these results with those from a previous optical isotope-shift study, the intrinsic quadrupole moment for the fission isomer 240fAm is deduced [Q0240f = 29.0(1.3) e b].

  18. Hydrophobization of epoxy nanocomposite surface with 1H,1H,2H,2H-perfluorooctyltrichlorosilane for superhydrophobic properties

    NASA Astrophysics Data System (ADS)

    Psarski, Maciej; Marczak, Jacek; Celichowski, Grzegorz; Sobieraj, Grzegorz B.; Gumowski, Konrad; Zhou, Feng; Liu, Weimin

    2012-10-01

    Nature inspires the design of synthetic materials with superhydrophobic properties, which can be used for applications ranging from self-cleaning surfaces to microfluidic devices. Their water repellent properties are due to hierarchical (micrometer- and nanometre-scale) surface morphological structures, either made of hydrophobic substances or hydrophobized by appropriate surface treatment. In this work, the efficiency of two surface treatment procedures, with a hydrophobic fluoropolymer, synthesized and deposited from 1H,1H,2H,2H-perfluorooctyltrichlorosilane (PFOTS) is investigated. The procedures involved reactions from the gas and liquid phases of the PFOTS/hexane solutions. The hierarchical structure is created in an epoxy nanocomposite surface, by filling the resin with alumina nanoparticles and micron-sized glass beads and subsequent sandblasting with corundum microparticles. The chemical structure of the deposited fluoropolymer was examined using XPS spectroscopy. The topography of the modified surfaces was characterized using scanning electron microscopy (SEM), and atomic force microscopy (AFM). The hydrophobic properties of the modified surfaces were investigated by water contact and sliding angles measurements. The surfaces exhibited water contact angles of above 150° for both modification procedures, however only the gas phase modification provided the non-sticking behaviour of water droplets (sliding angle of 3°). The discrepancy is attributed to extra surface roughness provided by the latter procedure.

  19. One dimensional 1H, 2H and 3H

    NASA Astrophysics Data System (ADS)

    Vidal, A. J.; Astrakharchik, G. E.; Vranješ Markić, L.; Boronat, J.

    2016-05-01

    The ground-state properties of one-dimensional electron-spin-polarized hydrogen 1H, deuterium 2H, and tritium 3H are obtained by means of quantum Monte Carlo methods. The equations of state of the three isotopes are calculated for a wide range of linear densities. The pair correlation function and the static structure factor are obtained and interpreted within the framework of the Luttinger liquid theory. We report the density dependence of the Luttinger parameter and use it to identify different physical regimes: Bogoliubov Bose gas, super-Tonks–Girardeau gas, and quasi-crystal regimes for bosons; repulsive, attractive Fermi gas, and quasi-crystal regimes for fermions. We find that the tritium isotope is the one with the richest behavior. Our results show unambiguously the relevant role of the isotope mass in the properties of this quantum system.

  20. Detailed Studies of Hydrocarbon Radicals: C2H Dissociation

    SciTech Connect

    Wittig, Curt

    2014-10-06

    A novel experimental technique was examined whose goal was the ejection of radical species into the gas phase from a platform (film) of cold non-reactive material. The underlying principle was one of photo-initiated heat release in a stratum that lies below a layer of CO2 or a layer of amorphous solid water (ASW) and CO2. A molecular precursor to the radical species of interest is deposited near or on the film's surface, where it can be photo-dissociated. It proved unfeasible to avoid the rampant formation of fissures, as opposed to large "flakes." This led to many interesting results, but resulted in our aborting the scheme as a means of launching cold C2H radical into the gas phase. A journal article resulted that is germane to astrophysics but not combustion chemistry.

  1. 2H NMR studies of supercooled and glassy aspirin

    NASA Astrophysics Data System (ADS)

    Nath, R.; Nowaczyk, A.; Geil, B.; Bohmer, R.

    2007-11-01

    Acetyl salicylic acid, deuterated at the methyl group, was investigated using 2H-NMR in its supercooled and glassy states. Just above the glass transition temperature the molecular reorientations were studied using stimulated-echo spectroscopy and demonstrated a large degree of similarity with other glass formers. Deep in the glassy phase the NMR spectra look similar to those reported for the crystal [A. Detken, P. Focke, H. Zimmermann, U. Haeberlen, Z. Olejniczak, Z. T. Lalowicz, Z. Naturforsch. A 50 (1995) 95] and below 20 K they are indicative for rotational tunneling with a relatively large tunneling frequency. Measurements of the spin-lattice relaxation times for temperatures below 150 K reveal a broad distribution of correlation times in the glass. The dominant energy barrier characterizing the slow-down of the methyl group is significantly smaller than the well defined barrier in the crystal.

  2. Study of the $\\tau^- to 3h^- 2h^+ \

    SciTech Connect

    Aubert, Bernard; Barate, R.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Tisserand, V.; Zghiche, A.; Grauges, E.; Palano, A.; Pappagallo, M.; Pompili, A.; Chen, J.C.; Qi, N.D.; Rong, G.; Wang, P.; Zhu, Y.S.; Eigen, G.; Ofte, I.; Stugu, B. /more authors..

    2005-05-04

    The branching fraction of the {tau}{sup -} {yields} 3h{sup -} 2h{sup +} {nu}{sub {tau}} decay (h = {pi}, K) is measured with the BABAR detector to be (8.56 {+-} 0.05 {+-} 0.42) x 10{sup -4}, where the first error is statistical and the second systematic. The observed structure of this decay is significantly different from the phase space prediction, with the {rho} resonance playing a strong role. The decay {tau}{sup -} {yields} f{sub 1}(1285){pi}{sup -}{nu}{sub {tau}}, with the f{sub 1}(1285) meson decaying to four charged pions, is observed and the branching fraction is measured to be (3.9 {+-} 0.7 {+-} 0.5) x 10{sup -4}.

  3. The ultraviolet spectrum of Herbig-Haro object 2H

    NASA Technical Reports Server (NTRS)

    Brugel, E. W.; Seab, C. G.; Shull, J. M.

    1982-01-01

    IUE spectra of Herbig-Haro object 2H are presented. The spectra show a strong 'excess' UV continuum and prominent emission lines of C, N, O, Si, Mg, and possibly Al. The continuum, F(lambda), exhibits a turnover shortward of about 1450 A, confirming for the first time the H0 two-photon nature of the emission source. A possible absorption feature near 1680 A, which could result from a new grain or molecular constituent in these protostellar objects is also noted. Recently computed models of steady shocks into partially ionized gas reproduce the two-photon spectral shape, but its observed intensity relative to H-beta and the Balmer continuum is anomalously high. It is suggested that a range of shock velocities, 70-100 km/s, or nonsteady, 'truncated' shocks may be responsible. Future high-sensitivity UV observations of HH objects may be used to probe grain extinction curves in star-forming regions.

  4. Doping dependent plasmon dispersion in 2 H -transition metal dichalcogenides

    NASA Astrophysics Data System (ADS)

    Müller, Eric; Büchner, Bernd; Habenicht, Carsten; König, Andreas; Knupfer, Martin; Berger, Helmuth; Huotari, Simo

    2016-07-01

    We report the behavior of the charge carrier plasmon of 2 H -transition metal dichalcogenides (TMDs) as a function of intercalation with alkali metals. Intercalation and concurrent doping of the TMD layers have a substantial impact on plasmon energy and dispersion. While the plasmon energy shifts are related to the intercalation level as expected within a simple homogeneous electron gas picture, the plasmon dispersion changes in a peculiar manner independent of the intercalant and the TMD materials. Starting from a negative dispersion, the slope of the plasmon dispersion changes sign and grows monotonously upon doping. Quantitatively, the increase of this slope depends on the orbital character (4 d or 5 d ) of the conduction bands, which indicates a decisive role of band structure effects on the plasmon behavior.

  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. Higher Order Parametric Excitation Modes for Spaceborne Quadrupole Mass Spectrometers

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

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

  8. Higher order parametric excitation modes for spaceborne quadrupole mass spectrometers

    SciTech Connect

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

    2011-12-15

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

  9. 2H and 18O Freshwater Isoscapes of Scotland

    NASA Astrophysics Data System (ADS)

    Meier-Augenstein, Wolfram; Hoogewerff, Jurian; Kemp, Helen; Frew, Danny

    2013-04-01

    Scotland's freshwater lochs and reservoirs provide a vital resource for sustaining biodiversity, agriculture, food production as well as for human consumption. Regular monitoring of freshwaters by the Scottish Environment Protection Agency (SEPA) fulfils legislative requirements with regards to water quality but new scientific methods involving stable isotope analysis present an opportunity combining these mandatory monitoring schemes with fundamental research to inform and deliver on current and nascent government policies [1] through gaining a greater understanding of Scottish waters and their importance in the context of climate change, environmental sustainability and food security. For example, 2H and 18O isoscapes of Scottish freshwater could be used to underpin research and its applications in: • Climate change - Using longitudinal changes in the characteristic isotope composition of freshwater lochs and reservoirs as proxy, isoscapes will provide a means to assess if and how changes in temperature and weather patterns might impact on precipitation patterns and amount. • Scottish branding - Location specific stable isotope signatures of Scottish freshwater have the potential to be used as a tool for provenancing and thus protecting premium Scottish produce such as Scottish beef, Scottish soft fruit and Scottish Whisky. During 2011 and 2012, with the support of SEPA more than 110 samples from freshwater lochs and reservoirs were collected from 127 different locations across Scotland including the Highlands and Islands. Here we present the results of this sampling and analysis exercise isotope analyses in form of 2H and 18O isoscapes with an unprecedented grid resolution of 26.5 × 26.5 km (or 16.4 × 16.4 miles). [1] Adaptation Framework - Adapting Our Ways: Managing Scotland's Climate Risk (2009): Scotland's Biodiversity: It's in Your Hands - A strategy for the conservation and enhancement of biodiversity in Scotland (2005); Recipe For Success - Scotland

  10. MEQALAC: (multiple electrostatic quadrupole linac): a new approach to low beta rf acceleration

    SciTech Connect

    Mobley, R.M.; Brodowski, J.J.; Gammel, G.M.; Keane, J.T.; Maschka, A.W.; Sanders, R.T.

    1980-01-01

    MEQALAC is an acronym for a multiple-beam electrostatic-quadrupole array linear accelerator. The principle of operation is very simple. It makes use of the fact that electrostatic quadrupoles focus more effectively at low velocities than conventional magnetic quadrupoles. Moreover, the pole-tip field of an electrostatic quadrupole is limited by field emission of electrons, and is not a function of the size of the quadrupole. Conventional magnetic quadrupoles, on the other hand, require increasingly high current densities if one attempts to scale to smaller size.

  11. Entanglement, magnetic and quadrupole moments properties of the mixed spin Ising-Heisenberg diamond chain

    NASA Astrophysics Data System (ADS)

    Abgaryan, V. S.; Ananikian, N. S.; Ananikyan, L. N.; Hovhannisyan, V.

    2015-02-01

    Thermal entanglement, magnetic and quadrupole moments properties of the mixed spin-1/2 and spin-1 Ising-Heisenberg model on a diamond chain are considered. Magnetization and quadrupole moment plateaus are observed for the antiferromagnetic couplings. Thermal negativity as a measure of quantum entanglement of the mixed spin system is calculated. Different behavior for the negativity is obtained for the various values of Heisenberg dipolar and quadrupole couplings. The intermediate plateau of the negativity has been observed at the absence of the single-ion anisotropy and quadrupole interaction term. When dipolar and quadrupole couplings are equal there is a similar behavior of negativity and quadrupole moment.

  12. CCQE, 2p2h excitations and ν—energy reconstruction

    SciTech Connect

    Nieves, J.; Simo, I. Ruiz; Sánchez, F.; Vacas, M. J. Vicente

    2015-05-15

    We analyze the MiniBooNE muon neutrino CCQE-like dσ/dT{sub μ} d cos θ{sub μ} data using a theoretical model that, among other nuclear effects, includes RPA correlations and 2p2h (multinucleon) mechanisms. These corrections turn out to be essential for the description of the data. We find that MiniBooNE CCQE-like data are fully compatible with former determinations of the nucleon axial mass M{sub A} ∼ 1.05 GeV. This is in sharp contrast with several previous analysis where anomalously large values of M{sub A} ∼ 1.4 GeV have been suggested. We also show that because of the the multinucleon mechanism effects, the algorithm used to reconstruct the neutrino energy is not adequate when dealing with quasielastic-like events. Finally, we analyze the MiniBooNE unfolded cross section, and show that it exhibits an excess (deficit) of low (high) energy neutrinos, which is an artifact of the unfolding process that ignores 2p2h mechanisms.

  13. Spin dependence of intrinsic and transition quadrupole moments

    SciTech Connect

    Jolos, R.V.; Brentano, P. von; Dewald, A.; Pietralla, N.

    2005-08-01

    The relation connecting an angular momentum dependence of the {gamma}-transition energies with the reduced transition probabilities B[E2;(I+2){sub gr}{yields}I{sub gr}] in the ground-state rotational band is derived based on the Bohr Hamiltonian. The relation is applicable to both {beta}-rigid and {beta}-soft both being {gamma}-rigid nuclei. Based on this result the approximate expression is obtained for the intrinsic quadrupole moment and, therefore, for the spectroscopic quadrupole moment in terms of the reduced E2 transition probabilities. It is shown that an angular momentum dependence of the intrinsic quadrupole moment can be well approximated by a linear function of I. The results obtained are direct consequences of the Bohr Hamiltonian with the Davidson potential.

  14. 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.

  15. 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.

  16. 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.

  17. A microelectromechanical systems-enabled, miniature triple quadrupole mass spectrometer.

    PubMed

    Wright, Steven; Malcolm, Andrew; Wright, Christopher; O'Prey, Shane; Crichton, Edward; Dash, Neil; Moseley, Richard W; Zaczek, Wojciech; Edwards, Peter; Fussell, Richard J; Syms, Richard R A

    2015-03-17

    Miniaturized mass spectrometers are becoming increasingly capable, enabling the development of many novel field and laboratory applications. However, to date, triple quadrupole tandem mass spectrometers, the workhorses of quantitative analysis, have not been significantly reduced in size. Here, the basis of a field-deployable triple quadrupole is described. The key development is a highly miniaturized ion optical assembly in which a sequence of six microengineered components is employed to generate ions at atmospheric pressure, provide a vacuum interface, effect ion guiding, and perform fragmentation and mass analysis. Despite its small dimensions, the collision cell efficiently fragments precursor ions and yields product ion spectra that are very similar to those recorded using conventional instruments. The miniature triple quadrupole has been used to detect thiabendazole, a common pesticide, in apples at a level of 10 ng/g. PMID:25708099

  18. 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.

  19. 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.

  20. Design and performance of the SRRC quadrupole magnets

    NASA Astrophysics Data System (ADS)

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

    1994-07-01

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

  1. Theoretical electric quadrupole transition probabilities for Ca, Sr and Ba

    NASA Technical Reports Server (NTRS)

    Bauschlicher, C. W., Jr.; Langhoff, S. R.; Jaffe, R. L.; Partridge, H.

    1984-01-01

    The 1D-1S quadrupole transition probabilities for Ca, Sr and Ba have been computed using extended GTO and STO valence basis sets and configuration-interaction wavefunctions that include the important core-valence correlation effects. For Ba and Sr, the relativistic contraction of the core orbitals was accounted for in the GTO calculations by a relativistic effective-core potential. The computed Einstein coefficient for Ca of 39.6/s is in excellent agreement with the recent experimental value of 40 + or - 8/s. The best Einstein coefficients for Sr (44.7/s) and Ba (2.98/s) imply increasing quadrupole line strengths down the column. Relativistic effects substantially increase the quadrupole Einstein coefficient for Ba.

  2. 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.

  3. Analyses of Weapons-Grade MOX VVER-1000 Neutronics Benchmarks: Pin-Cell Calculations with SCALE/SAS2H

    SciTech Connect

    Ellis, R.J.

    2001-01-11

    A series of unit pin-cell benchmark problems have been analyzed related to irradiation of mixed oxide fuel in VVER-1000s (water-water energetic reactors). One-dimensional, discrete-ordinates eigenvalue calculations of these benchmarks were performed at ORNL using the SAS2H control sequence module of the SCALE-4.3 computational code system, as part of the Fissile Materials Disposition Program (FMDP) of the US DOE. Calculations were also performed using the SCALE module CSAS to confirm the results. The 238 neutron energy group SCALE nuclear data library 238GROUPNDF5 (based on ENDF/B-V) was used for all calculations. The VVER-1000 pin-cell benchmark cases modeled with SAS2H included zero-burnup calculations for eight fuel material variants (from LEU UO{sub 2} to weapons-grade MOX) at five different reactor states, and three fuel depletion cases up to high burnup. Results of the SAS2H analyses of the VVER-1000 neutronics benchmarks are presented in this report. Good general agreement was obtained between the SAS2H results, the ORNL results using HELIOS-1.4 with ENDF/B-VI nuclear data, and the results from several Russian benchmark studies using the codes TVS-M, MCU-RFFI/A, and WIMS-ABBN. This SAS2H benchmark study is useful for the verification of HELIOS calculations, the HELIOS code being the principal computational tool at ORNL for physics studies of assembly design for weapons-grade plutonium disposition in Russian reactors.

  4. 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%.

  5. 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.

  6. 2F and 2H evaporator loop evaluation closure report

    SciTech Connect

    Bates, W.F.

    1994-01-28

    As a result of the Concentrate Transfer System (CTS) tank ventilation system contamination event, a task team was formed to evaluate instrument loops associated with waste reduction equipment. During the event a conductivity probe designed to provide an alarm and initiate an interlock failed to respond to the presence of liquid. An investigation revealed that the probe had become disconnected from the loop. The daily functional check of the conductivity probe circuit only tested the circuit continuity from the ventilation unit to the control room and did not actually test the probe. To test the continuity, a test switch was used to simulate the conducting probe. Because the functional check did not test each part of the loop, the test could be satisfactorily completed even though the probe itself was inoperable. The function of the task team was to develop a list of loops and interlocks prioritized by importance and likelihood of similar failure. The team evaluated the associated loop calibration and functional test procedures to verify that they are adequate to ensure loop performance on a periodic frequency. This report documents the evaluation findings and associated actions required prior to startup of the 2F and 2H evaporators.

  7. Ca2+/H+ exchange in acidic vacuoles of Trypanosoma brucei.

    PubMed Central

    Vercesi, A E; Moreno, S N; Docampo, R

    1994-01-01

    The use of digitonin to permeabilize the plasma membrane of Trypanosoma brucei procyclic and bloodstream trypomastigotes allowed the identification of a non-mitochondrial nigericin-sensitive Ca2+ compartment. The proton ionophore carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP) was able to cause Ca2+ release from this compartment, which was also sensitive to sodium orthovanadate. Preincubation of the cells with the vacuolar H(+)-ATPase inhibitor bafilomycin A1 greatly reduced the nigericin-sensitive Ca2+ compartment. Bafilomycin A1 inhibited the initial rate of ATP-dependent non-mitochondrial Ca2+ uptake and stimulated the initial rate of nigericin-induced Ca2+ release by permeabilized procyclic trypomastigotes. ATP-dependent and bafilomycin A1- and 7-chloro-4-nitrobenz-2-oxa-1,3-diazole (NBD-Cl)-sensitive Acridine Orange uptake was demonstrated in permeabilized cells. Under these conditions Acridine Orange was concentrated in abundant cytoplasmic round vacuoles by a process inhibited by bafilomycin A1, NBD-Cl, nigericin, and Ca2+. Vanadate or EGTA significantly increased Acridine Orange uptake, while Ca2+ released Acridine Orange from these preparations, thus suggesting that the dye and Ca2+ were being accumulated in the same acidic vacuole. Acridine Orange uptake was reversed by nigericin, bafilomycin A1 and NH4Cl. The results are consistent with the presence of a Ca2+/H(+)-ATPase system pumping Ca2+ into an acidic vacuole, that we tentatively named the acidocalcisome. Images Figure 5 PMID:7998937

  8. Electron paramagnetic resonance spectra and structures of Cu(C sub 2 H sub 4 ), Cu(C sub 2 H sub 4 ) sub 2 , and Cu(C sub 2 H sub 4 ) sub 3 in hydrocarbon matrices

    SciTech Connect

    Howard, J.A.; Joly, H.A.; Mile, B. )

    1990-02-22

    Two mononuclear {pi}-complexes, Cu(C{sub 2}H{sub 4}) and Cu(C{sub 2}H{sub 4}){sub 2}, have been positively identified by EPR spectroscopy from reaction of Cu atoms and ethylene at 77 K in inert hydrocarbon matrices on a rotating cryostat. The spectra of these copper(O) complexes are consistent with dative bonding for both species and with a C{sub 2v} structure for Cu(C{sub 2}H{sub 4}) and a D{sub 2h} structure for Cu(C{sub 2}H{sub 4}){sub 2}. Spectra of Cu({sup 13}CH{sub 2}CH{sub 2}) and Cu({sup 13}CH{sub 2}CH{sub 2}){sub 2} are consistent with these assignments. A third complex is formed in both adamantane and cyclohexane that could be Cu(C{sub 2}H{sub 4}){sub 2} with a structure other than D{sub 2h} but is more likely to be the mononuclear trisligand complex Cu(C{sub 2}H{sub 4}){sub 3} with a D{sub 3h} structure. In the absence of a well-resolved isotropic spectrum of Cu({sup 13}CH{sub 2}CH{sub 2}){sub 3}, this assignment must however be taken as tentative.

  9. Global distributions of C2H6, C2H2, HCN, and PAN retrieved from MIPAS reduced spectral resolution measurements

    NASA Astrophysics Data System (ADS)

    Wiegele, A.; Glatthor, N.; Höpfner, M.; Grabowski, U.; Kellmann, S.; Linden, A.; Stiller, G.; von Clarmann, T.

    2011-08-01

    Vertical profiles of mixing ratios of C2H6, C2H2, HCN, and PAN were retrieved from MIPAS reduced spectral resolution nominal mode limb emission measurements. The retrieval strategy followed that of the analysis of MIPAS high resolution measurements, with occasional adjustments to cope with the reduced spectral resolution under which MIPAS is operated since 2005. Largest mixing ratios are found in the troposphere, and reach 1.2 ppbv for C2H6, 1 ppbv for HCN, 600 pptv for PAN, and 450 pptv for C2H2. The estimated precision in case of significantly enhanced mixing ratios (including measurement noise and propagation of uncertain parameters randomly varying in the time domain) and altitude resolution are typically 10 %, 3-4.5 km for C2H6, 15 %, 4-6 km for HCN, 6 %, 2.5-3.5 km for PAN, and 7 %, 2.5-4 km for C2H2.

  10. Order and dynamics in mixtures of membrane glucolipids from Acholeplasma laidlawii studied by sup 2 H NMR

    SciTech Connect

    Eriksson, P.O.; Rilfors, L.; Lundberg, A.; Lindblom, G.; Wieslander, A. )

    1991-05-21

    The two dominant glucolipids in Acholeplasma laidlawii, viz., 1,2-diacyl-3-O-({alpha}-D-glucopyranosyl)-sn-glycerol (MGlcDG) and 1,2-diacyl-3-O-({alpha}-D-glucopyranosyl-(1{yields}2)-O-{alpha}-D-glucopyranosyl)-sn-glycerol (DGlcDG), have markedly different phase behavior. MGlcDG has an ability to form nonlamellar phases, whereas DGlcDG only forms lamellar phases. For maintenance of a stable lipid bilayer, the polar headgroup composition in A. laidlawii is metabolically regulated in vivo, in response to changes in the growth conditions. To investigate the mechanism behind the lipid regulation the authors have here studied bilayers of mixtures of unsaturated MGlcDG and DGlcDG, containing a small fraction of biosynthetically incorporated per-deuterated palmitic acid, with {sup 2}H NMR. The order-parameter profile of the acyl chains and an apparent transverse spin relaxation rate (R{sub 2}) were determined from dePaked quadrupole-echo spectra. The variation of order with lipid composition is rationalized from simple packing constraints. The relaxation data indicate the presence of slow reorientational motions, such as collective bilayer fluctuations and/or lipid lateral diffusion over a curved bilayer surface. The variation of acyl-chain order and bilayer curvature and/or fluctuations with sample composition are discussed in relation to the tendency of MGlcDG to form nonlamellar phases in vitro and in relation to the lipid regulation in vivo.

  11. Electric quadrupole excitations in the interactions of Y-89 with relativistic nuclei

    NASA Technical Reports Server (NTRS)

    Norbury, John W.

    1989-01-01

    The first complete calculations of electric quadrupole excitations in relativistic nucleus-nucleus collisions are presented herein. Neutron emission from Y-89 is studied and quadrupole effects are found to be a significant fraction of the cross section.

  12. Microwave spectrum and quadrupole coupling constant tensor of gauche-isobutyl chloride

    NASA Astrophysics Data System (ADS)

    Niide, Yuzuru; Ohkoshi, Ichiro

    1991-04-01

    The microwave spectra of two 35Cl and 37Cl species of isobutyl chloride have been measured in the frequency region of 14-39 GHz. Both the a-type R-branch and the b-type Q-branch transitions for the 35Cl species, and a-type R-branch transitions for the 37Cl species of one conformer, gauche, were assigned. The values of the rotational constants of the gauche form in the ground vibrational state were determined to be A = 7498.57 ± 0.62 MHz, B = 2146.321 ± 0.016 MHz, and C = 1793.715 ± 0.009 MHz for the 35Cl species; and A = 7527.6 ± 2.2 MHz, B = 2091.774 ± 0.032 MHz, and C = 1755.493 ± 0.018 MHz for the 37Cl species, respectively. From the quadrupole hyperfine splittings of the 35Cl and 37Cl nuclei, the nuclear quadrupole coupling constants in the principal axes system for the gauche were determined to be χ aa = -51.6 ± 5.4 MHz, χ bb = 16.9 ± 2.8 MHz, χ cc = 34.7 ± 6.0 MHz for the 35Cl species; and χ aa = -39.3 ± 9.9 MHz, χ bb = 14.3 ± 7.7 MHz, χ cc = 25.0 ± 12.5 MHz for the 37Cl species, respectively.

  13. 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.; Schlüter, F.; Sonnabend, K.; Stoica, V. I.; Wörtche, 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, (α ,α‧ γ) and (γ ,γ‧) experiments were performed on 124Sn. In both reactions, Jπ =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 (γ ,γ‧) experiment, while the (α ,α‧ γ) experiment at the chosen kinematics strongly favors the excitation of surface modes because of the strong α-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 γ-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.

  14. Full-dimensional quantum dynamics study of the H2 + C2H → H + C2H2 reaction on an ab initio potential energy surface.

    PubMed

    Chen, Liuyang; Shao, Kejie; Chen, Jun; Yang, Minghui; Zhang, Dong H

    2016-05-21

    This work performs a time-dependent wavepacket study of the H2 + C2H → H + C2H2 reaction on a new ab initio potential energy surface (PES). The PES is constructed using neural network method based on 68 478 geometries with energies calculated at UCCSD(T)-F12a/aug-cc-pVTZ level and covers H2 + C2H↔H + C2H2, H + C2H2 → HCCH2, and HCCH2 radial isomerization reaction regions. The reaction dynamics of H2 + C2H → H + C2H2 are investigated using full-dimensional quantum dynamics method. The initial-state selected reaction probabilities are calculated for reactants in eight vibrational states. The calculated results showed that the H2 vibrational excitation predominantly enhances the reactivity while the excitation of bending mode of C2H slightly inhibits the reaction. The excitations of two stretching modes of C2H molecule have negligible effect on the reactivity. The integral cross section is calculated with J-shift approximation and the mode selectivity in this reaction is discussed. The rate constants over 200-2000 K are calculated and agree well with the experimental measured values. PMID:27208951

  15. Ion-neutral reaction of the C2H2N+ cation with C2H2: An experimental and theoretical study

    NASA Astrophysics Data System (ADS)

    Fathi, P.; Geppert, W. D.; Kaiser, A.; Ascenzi, D.

    2016-03-01

    The ion-neutral reactions of the C2H2N+ cation with C2H2 have been investigated using a Guided Ion Beam Mass Spectrometer (GIB-MS). The following ionic products were observed: CH3+, C2H2+, C2H3+, HNC+ /HCN+ , HCNH+, C3H+ , C2N+ , C3H3+, HCCN+ and C4H2N+ . Theoretical calculations have been carried out to propose reaction pathways leading to the observed products. These processes are of relevance for the generation of long chain nitrogen-containing species and they may be of interest for the chemistry of Titan's ionosphere or circumstellar envelopes.

  16. Theoretical study of the C-H bond dissociation energies of CH4, C2H2, C2H4, and H2C2O

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles W., Jr.; Langhoff, Stephen R.

    1991-01-01

    The successive C-H bond dissociation energies of CH4, C2H2, C2H4, and H2C2O (ketene) are determined using large-basis sets and a high level of correlation treatment. For CH4, C2H2, and C2H4 the computed values are in excellent agreement with experiment. Using these results, the values 107.9 + or - 2.0 and 96.7 + or - 2.0 kcal/mol are recommended for the C-H bond dissociation energies of H2C2O and HC2O, respectively.

  17. Full-dimensional quantum dynamics study of the H2 + C2H → H + C2H2 reaction on an ab initio potential energy surface

    NASA Astrophysics Data System (ADS)

    Chen, Liuyang; Shao, Kejie; Chen, Jun; Yang, Minghui; Zhang, Dong H.

    2016-05-01

    This work performs a time-dependent wavepacket study of the H2 + C2H → H + C2H2 reaction on a new ab initio potential energy surface (PES). The PES is constructed using neural network method based on 68 478 geometries with energies calculated at UCCSD(T)-F12a/aug-cc-pVTZ level and covers H2 + C2H↔H + C2H2, H + C2H2 → HCCH2, and HCCH2 radial isomerization reaction regions. The reaction dynamics of H2 + C2H → H + C2H2 are investigated using full-dimensional quantum dynamics method. The initial-state selected reaction probabilities are calculated for reactants in eight vibrational states. The calculated results showed that the H2 vibrational excitation predominantly enhances the reactivity while the excitation of bending mode of C2H slightly inhibits the reaction. The excitations of two stretching modes of C2H molecule have negligible effect on the reactivity. The integral cross section is calculated with J-shift approximation and the mode selectivity in this reaction is discussed. The rate constants over 200-2000 K are calculated and agree well with the experimental measured values.

  18. Measured Effects of a Longitudinal Solenoidal Field on an Iron Quadrupole

    NASA Astrophysics Data System (ADS)

    Ecklund, S.; Seeman, J. T.; Wolf, Z.

    1997-05-01

    We have measured the effects of a longitudinal solenoidal field on the field harmonics of an iron dominated quadrupole. These measurements are useful when designing a colliding beam interaction region where the first quadrupole is very near the solenoidal field of the physics detector. The effects of mirror plates, quadrupole excition, skew quadrupole windings, dipole windings, and solenoidal fields that enter at an angle have been measured. Conclusions and interpretations are given.

  19. Application of switched-power techniques to quadrupoles

    SciTech Connect

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

    1988-01-01

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

  20. 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.

  1. 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.

  2. Rotating magnetic quadrupole current drive for field-reversed configurations

    SciTech Connect

    Milroy, Richard D.; Guo, H.Y.

    2005-07-15

    In the translation, confinement, and sustainment experiment [A. L. Hoffman, H. Y. Guo, J. T. Slough, S. J. Tobin, L. S. Schrank, W. A. Reass, and G. A. Wurden, Fusion Sci. Technol. 41, 92 (2002)], field-reversed configurations (FRCs) are created and sustained using a rotating magnetic field (RMF). The RMF is usually in the form of a rotating dipole, which in vacuum penetrates uniformly to the axis of symmetry. However, plasma conditions in the FRC normally adjust so that the RMF only partially penetrates the plasma column. We have investigated the possibility of using a rotating quadrupole rather than a rotating dipole magnetic field. The vacuum field from a quadrupole is proportional to radius and cannot penetrate to the axis of symmetry; however, this is not a disadvantage if the current drive is confined to the outer region of the FRC. It was found that the quadrupole drive efficiency is comparable to that of a dipole, but the rotating dipole is more effective at stabilizing the n=2 rotational instability. A strong internal oscillation in B{sub {theta}} is often observed in FRCs sustained by a quadrupole field. The spectral content of the signals indicates that an internal n=1 magnetic structure forms and corotates with the electrons. Similar but much lower amplitude structures can form when a rotating dipole is employed (edge-driven mode)

  3. Quadrupole transport experiment with space charge dominated cesium ion beam

    SciTech Connect

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

    1984-08-01

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

  4. Measurement of an atomic quadrupole moment using dynamic decoupling

    NASA Astrophysics Data System (ADS)

    Akerman, Nitzan; Shaniv, Ravid; Ozeri, Roee

    2016-05-01

    Some of the best clocks today are ion-based optical clocks. These clocks are referenced to a narrow optical transition in a trapped ion. An example for such a narrow transition is the electric quadrupole E 2 transition between states with identical parity. An important systematic shift of such a transition is the quadrupole shift resulting from the electric field gradient inherent to the ion trap. We present a new dynamic decoupling method that rejects magnetic field noise while measuring the small quadrupole shift of the optical clock transition. Using our sequence we measured the quadrupole moment of the 4D5/2 level in a trapped 88 Sr+ ion to be 2 .973-0 . 033 + 0 . 026 ea02 , where e is the electron charge and a0 is the Bohr radius. Our measurement improves the uncertainty of this value by an order of magnitude and thus helps mitigate an important systematic uncertainty in 88 Sr+ based optical atomic clocks and verifies complicated many-body quantum calculations.

  5. Two-stream instability model with electrons trapped in quadrupoles

    NASA Astrophysics Data System (ADS)

    Channell, P. J.

    2009-08-01

    We formulate the theory of the two-stream instability (e-cloud instability) with electrons trapped in quadrupole magnets. We show that a linear instability theory can be sensibly formulated and analyzed. The growth rates are considerably smaller than the linear growth rates for the two-stream instability in drift spaces and are close to those actually observed.

  6. 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.

  7. 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.

  8. Is the Reaction of C3N(-) with C2H2 a Possible Process for Chain Elongation in Titan's Ionosphere?

    PubMed

    Lindén, Fredrik; Alcaraz, Christian; Ascenzi, Daniela; Guillemin, Jean-Claude; Koch, Leopold; Lopes, Allan; Polášek, Miroslav; Romanzin, Claire; Žabka, Jan; Zymak, Illia; Geppert, Wolf D

    2016-07-14

    The reaction of C3N(-) with acetylene was studied using three different experimental setups, a triple quadrupole mass spectrometer (Trento), a tandem quadrupole mass spectrometer (Prague), and the "CERISES" guided ion beam apparatus at Orsay. The process is of astrophysical interest because it can function as a chain elongation mechanism to produce larger anions that have been detected in Titan's ionosphere by the Cassini Plasma Spectrometer. Three major products of primary processes, C2H(-), CN(-), and C5N(-), have been identified, whereby the production of the cyanide anion is probably partly due to collisional induced dissociation. The formations of all these products show considerable reaction thresholds and also display comparatively small cross sections. Also, no strong signals of anionic products for collision energies lower than 1 eV have been observed. Ab initio calculations have been performed to identify possible pathways leading to the observed products of the title reaction and to elucidate the thermodynamics of these processes. Although the productions of CN(-) and C5N(-) are exoergic, all reaction pathways have considerable barriers. Overall, the results of these computations are in agreement with the observed reaction thresholds. Due to the existence of considerable reaction energy barriers and the small observed cross sections, the title reaction is not very likely to play a major role in the buildup of large anions in cold environments like the interstellar medium or planetary and satellite ionospheres. PMID:27135984

  9. Electron capture processes in Li2+ + H collisions

    NASA Astrophysics Data System (ADS)

    Yan, Ling Ling; Liu, Ling; Wang, Jian Guo; Janev, Ratko K.; Buenker, Robert J.

    2015-01-01

    The electron capture processes in Li2 + + H collisions have been investigated by using the quantum-mechanical molecular-orbital close-coupling method and the two-center atomic-orbital close-coupling method in the energy ranges of 10-8-10 keV/u and 0.1-300 keV/u, respectively. The capture to singlet and triplet systems of states of Li+(1 s,n l 2S + 1L) is considered separately. Total, n,S-resolved and n,l,S-resolved electron capture cross sections are calculated and compared with the results of available experimental and theoretical studies. The present calculations show that the n = 2 shell of Li+ is the main capture channel for all energies considered in both the singlet and triplet case. While for collision energies E> 5 keV/u, the cross sections for capture to the n = 2 manifold are of the same order of magnitude for both the singlet and triplet states (with the 2 p capture cross section being dominant), for energies below ~5 keV/u the cross sections for capture to the n = 2 triplet manifold is significantly (more than three orders of magnitude at 0.1 keV/u) larger than that for capture to the n = 2 singlet manifold of states (with the 2 s capture cross section being dominant). The capture dynamics at low collision energies is discussed in considerable detail, revealing the important role of rotational couplings in population of l> 0 capture states. The elastic scattering processes have been studied as well in the energy range of 10-8-1 keV/u. The calculated elastic scattering cross section is much larger than the electron capture cross section in both the singlet and triplet case. However, as the collision energy increases, the difference between the elastic and electron capture cross sections decreases rapidly.

  10. High/variable mixture ratio O2/H2 engine

    NASA Technical Reports Server (NTRS)

    Adams, A.; Parsley, R. C.

    1988-01-01

    Vehicle/engine analysis studies have identified the High/Dual Mixture Ratio O2/H2 Engine cycle as a leading candidate for an advanced Single Stage to Orbit (SSTO) propulsion system. This cycle is designed to allow operation at a higher than normal O/F ratio of 12 during liftoff and then transition to a more optimum O/F ratio of 6 at altitude. While operation at high mixture ratios lowers specific impulse, the resultant high propellant bulk density and high power density combine to minimize the influence of atmospheric drag and low altitude gravitational forces. Transition to a lower mixture ratio at altitude then provides improved specific impulse relative to a single mixture ratio engine that must select a mixture ratio that is balanced for both low and high altitude operation. This combination of increased altitude specific impulse and high propellant bulk density more than offsets the compromised low altitude performance and results in an overall mission benefit. Two areas of technical concern relative to the execution of this dual mixture ratio cycle concept are addressed. First, actions required to transition from high to low mixture ratio are examined, including an assessment of the main chamber environment as the main chamber mixture ratio passes through stoichiometric. Secondly, two approaches to meet a requirement for high turbine power at high mixture ratio condition are examined. One approach uses high turbine temperature to produce the power and requires cooled turbines. The other approach incorporates an oxidizer-rich preburner to increase turbine work capability via increased turbine mass flow.

  11. Studies on 2H NMR and single crystal X-ray diffraction of thermochromic bis ( N, N-diethyl-1,2-ethanediamine) nickel(II) complexes with and without structural phase transitions

    NASA Astrophysics Data System (ADS)

    Ikeda, Ryuichi; Kotani, Kyoko; Ohki, Hiroshi; Ishimaru, Shin'ichi; Okamoto, Ken-Ichi; Ghosh, Ashutosh

    1995-02-01

    The thermochromic complex bis( N, N-diethyl-1,2-ethanediamine) ((C 2H 5) 2NC 2H 4NH 2) nickel(II) perchlorate([Ni(dieten) 2](ClO 4) 2) was studied by single crystal X-ray diffraction and found to form a triclinic lattice with space group P 1¯, a = 8.108(1) Å, b = 8.835(1) Å, c = 9.736(1) Å, α = 94.24(1)°, β = 114.28(1)°, γ = 116.49(1)°, and Z = 1 being isomorphous with that of [Cu(dieten) 2](ClO 4) 2 which has been reported to have a thermochromic phase transition. The temperature dependences of 2H NMR spectra in [Ni(dieten- d2) 2]X 2 (dieten- d2: (C 2H 5) 2NC 2H 4ND 2; X: ClO 4, BF 4, Br, NO 3, I) were observed and quadrupole coupling constants e2Qq and asymmetry parameters η were evaluated. Below room temperature, an almost rigid structure of the ND 2 group was derived by analyzing the spectra. For perchlorate and tetrafluoroborate with colour changes at respective phase transition temperatures ( Tc), quadrupole parameters were also changed discontinuously at Tc. The analysis of spectra observed above Tc afforded two-site jumps of the N-D bond by angles of 52-55° supporting the ring-puckering model of the five-membered chelate ring. However, iodide having no phase transition showed continuous changes of both e2Qq and η values with increasing temperature up to 450 K. These results which cannot be attributed to the puckering motion were explained by whole complex reorientation. These molecular motions are discussed in connection with the colour change observed in these complexes.

  12. Study of the reactions /sup 2/H(d, p)/sup 3/H and /sup 2/H(d,n)/sup 3/He with a polarized deuteron beam. Extrapolation of the cross sections to the low-energy region

    SciTech Connect

    Ad'yasevich, B.P.; Antonenko, V.G.; Bragin, V.N.

    1981-05-01

    On the basis of analysis of experimental data on the vector analyzing power of the nuclear reactions /sup 2/H(d,p)/sup 3/H and /sup 2/H(d,n)/sup 3/He and data on the total cross sections for these reactions at energies from 13 to 485 keV we have separated the total cross sections into partial cross sections for s and p waves and have calculated the total cross sections for very low energies down to 0.3 keV. For these same reactions we have calculated the intensities of production of energetic products in a heated deuterium plasma. A formula for practical calculations of this intensity is obtained.

  13. Static quadrupole moments of 106Agm and 109Agm and the electric field gradient of Ag in Zn and Cd

    NASA Astrophysics Data System (ADS)

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

    1984-12-01

    Low temperature nuclear orientation of 106Agm and 110Agm in Zn and Fe and level mixing resonances on 109Agm have been measured in order to deduce Q and Vzz values. A fourth-order resonance in 109AgmZn has been found with a full width at half maximum of 1.9 × 10-9 eV, and Vzz(AgCd)Vzz(AgZn)=1.0064(34) was deduced. The electric quadrupole moments found in the literature, reevaluated for Sternheimer correction Q(108Agm)=+1.32(7) b and Q(110Agm)=+1.44(10) b, are used for the calibration of Vzz and yield Q(106Agm)=+1.11(11) b, Q(109Agm)=(+)0.97(11) b, and Vzz(AgZn)=+4.2(5)×1017 V/cm2. Furthermore, μ(106Agm)=(+)3.82(8)μN and several δ(E 2M 1) mixing ratios in 106Pd are also determined. The quadrupole moments are in good agreement with Yukawa-plus-exponential macroscopic model and folded-Yukawa microscopic model calculations. The particle states can be described in terms of deformed Nilsson orbitals or three valence-proton holes coupled to a quadrupole vibrator.

  14. Rotational Spectroscopy of HB 33S: The Quadrupole Coupling Constant of 33S in Thioborine

    NASA Astrophysics Data System (ADS)

    Bizzocchi, L.; Degli Esposti, C.; Dore, L.

    2002-10-01

    The unstable HBS molecule has been produced in the gas phase by a high-temperature reaction between crystalline boron and hydrogen sulfide. Ground state rotational spectra have been observed in the millimeter-wave region, from 75 to 460 GHz, for the previously unobserved H 11B 33S and H 10B 33S isotopic species. The analysis of the hyperfine structure produced by the 10/11B and 33S nuclear spins in the low- J rotational transitions has yielded the first evaluation of the quadrupole coupling constant of 33S in the thioborine molecule, which was 6.361(15) MHz in H 11B 33S and 6.329(17) MHz in H 10B 33S. In addition, further measurements have been performed for the most abundant isotopomers H 10/11B 32/34S, for which improved values of rotational, centrifugal, and hyperfine structure constants have been determined.

  15. 242-16H 2H EVAPORATOR POT SAMPLING FINAL REPORT

    SciTech Connect

    Krementz, D; William Cheng, W

    2008-06-11

    Due to the materials that are processed through 2H Evaporator, scale is constantly being deposited on the surfaces of the evaporator pot. In order to meet the requirements of the Nuclear Criticality Safety Analysis/Evaluation (NCSA/NCSE) for 2H Evaporator, inspections of the pot are performed to determine the extent of scaling. Once the volume of scale reaches a certain threshold, the pot must be chemically cleaned to remove the scale. Prior to cleaning the pot, samples of the scale are obtained to determine the concentration of uranium and plutonium and also to provide information to assist with pot cleaning. Savannah River National Laboratory (SRNL) was requested by Liquid Waste Organization (LWO) Engineering to obtain these samples from two locations within the evaporator. Past experience has proven the difficulty of successfully obtaining solids samples from the 2H Evaporator pot. To mitigate this risk, a total of four samplers were designed and fabricated to ensure that two samples could be obtained. Samples had previously been obtained from the cone surface directly below the vertical access riser using a custom scraping tool. This tool was fabricated and deployed successfully. A second scraper was designed to obtain sample from the nearby vertical thermowell and a third scraper was designed to obtain sample from the vertical pot wall. The newly developed scrapers both employed a pneumatically actuated elbow. The scrapers were designed to be easily attached/removed from the elbow assembly. These tools were fabricated and deployed successfully. A fourth tool was designed to obtain sample from the opposite side of the pot under the tube bundle. This tool was fabricated and tested, but the additional modifications required to make the tool field-ready could not be complete in time to meet the aggressive deployment schedule. Two samples were obtained near the pot entry location, one from the pot wall and the other from the evaporator feed pipe. Since a third

  16. Electron swarm parameters in pure C2H2 and in C2H2-Ar mixtures and electron collision cross sections for the C2H2 molecule

    NASA Astrophysics Data System (ADS)

    Nakamura, Yoshiharu

    2010-09-01

    Electron swarm parameters (the drift velocity and the longitudinal diffusion coefficient) were measured in pure C2H2 and also in C2H2-Ar mixtures containing 0.517% and 5.06% acetylene over wide E/N ranges. These swarm parameters were analysed using a Boltzmann equation analysis and a set of electron collision cross sections for the C2H2 molecule was derived so that it was consistent with the present swarm data and published ionization coefficient. The present result suggested the presence of a Ramsauer-Townsend minimum in the elastic momentum transfer cross section at 0.08 eV and prominent threshold and resonance peaks in the ν4/ν5 vibrational excitation cross section. The present cross section set was also confirmed to be consistent with the published experimental total cross section of C2H2.

  17. Theory of nuclear magnetic relaxation

    NASA Technical Reports Server (NTRS)

    Mcconnell, J.

    1983-01-01

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

  18. An online database of nuclear electromagnetic moments

    NASA Astrophysics Data System (ADS)

    Mertzimekis, T. J.; Stamou, K.; Psaltis, A.

    2016-01-01

    Measurements of nuclear magnetic dipole and electric quadrupole moments are considered quite important for the understanding of nuclear structure both near and far from the valley of stability. The recent advent of radioactive beams has resulted in a plethora of new, continuously flowing, experimental data on nuclear structure - including nuclear moments - which hinders the information management. A new, dedicated, public and user friendly online database

  19. Central nervous system dysfunction in a mouse model of FA2H deficiency.

    PubMed

    Potter, Kathleen A; Kern, Michael J; Fullbright, George; Bielawski, Jacek; Scherer, Steven S; Yum, Sabrina W; Li, Jian J; Cheng, Hua; Han, Xianlin; Venkata, Jagadish Kummetha; Khan, P Akbar Ali; Rohrer, Bärbel; Hama, Hiroko

    2011-07-01

    Fatty acid 2-hydroxylase (FA2H) is responsible for the synthesis of myelin galactolipids containing hydroxy fatty acid (hFA) as the N-acyl chain. Mutations in the FA2H gene cause leukodystrophy, spastic paraplegia, and neurodegeneration with brain iron accumulation. Using the Cre-lox system, we developed two types of mouse mutants, Fa2h(-/-) mice (Fa2h deleted in all cells by germline deletion) and Fa2h(flox/flox) Cnp1-Cre mice (Fa2h deleted only in oligodendrocytes and Schwann cells). We found significant demyelination, profound axonal loss, and abnormally enlarged axons in the CNS of Fa2h(-/-) mice at 12 months of age, while structure and function of peripheral nerves were largely unaffected. Fa2h(-/-) mice also exhibited histological and functional disruption in the cerebellum at 12 months of age. In a time course study, significant deterioration of cerebellar function was first detected at 7 months of age. Further behavioral assessments in water T-maze and Morris water maze tasks revealed significant deficits in spatial learning and memory at 4 months of age. These data suggest that various regions of the CNS are functionally compromised in young adult Fa2h(-/-) mice. The cerebellar deficits in 12-month-old Fa2h(flox/flox) Cnp1-Cre mice were indistinguishable from Fa2h(-/-) mice, indicating that these phenotypes likely stem from the lack of myelin hFA-galactolipids. In contrast, Fa2h(flox/flox) Cnp1-Cre mice did not show reduced performance in water maze tasks, indicating that oligodendrocytes are not involved in the learning and memory deficits found in Fa2h(-/-) mice. These findings provide the first evidence that FA2H has an important function outside of oligodendrocytes in the CNS. PMID:21491498

  20. Measurement reports for the cryogenically-cooled drift tube quadrupoles

    SciTech Connect

    1993-12-31

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

  1. 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.

  2. 3D simulations of an electrostatic quadrupole injector

    SciTech Connect

    Grote, D.P. |; Friedman, A.; Yu, S.

    1993-02-01

    Analysis of the dynamics of a space charge dominated beam in a lattice of electrostatic focusing structures requires a full three-dimensional conic that includes self-consistent space charge fields and the fields from the complex conductor shapes. The existing WARP3d code, a particle simulation code which has been developed for heavy-ion fusion (HIF) applications contains machinery for handling particles in three-dimensional fields. A successive overrelaxation field solver with subgrid-scale placement of boundaries for rounded surface and four-fold symmetry has been added to the code. The electrostatic quadrupole (ESQ) injector for the ILSE accelerator facility being planned at Lawrence Berkeley Laboratory is shown as an application. The issue of concern is possible emittance degradation because the focusing voltages are a significant fraction of the particles` energy and because there are significant nonlinear fields arising from the shapes of the quadrupole structures.

  3. Nb3Sn Quadrupoles Designs For The LHC Upgrades

    SciTech Connect

    Felice, Helene

    2008-05-19

    In preparation for the LHC luminosity upgrades, high field and large aperture Nb{sub 3}Sn quadrupoles are being studied. This development has to incorporate all the relevant features for an accelerator magnet like alignment and cooling channels. The LARP HQ model is a high field and large bore quadrupole that will meet these requirements. The 2-layer coils are surrounded by a structure based on key and bladder technology with supporting iron yoke and aluminum shell. This structure is aimed at pre-stress control, alignment and field quality. We present here the magnetic and mechanical design of HQ, along with recent progress on the development of the first 1-meter model.

  4. 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.

  5. 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.

  6. Microwave spectra and quadrupole coupling measurements for methyl rhenium trioxide

    NASA Astrophysics Data System (ADS)

    Sickafoose, S. M.; Wikrent, P.; Drouin, B. J.; Kukolich, S. G.

    1996-12-01

    Microwave rotational transitions for J' ← J = 1 ← 0 and 2 ← 1 were measured in the 6-14 GHz range for methyl rhenium trioxide using a Flygare-Balle type, pulsed-beam spectrometer. The rotational constants for the most abundant isotopomers are B( 187Re) = 3466.964(2) MHz and B( 185Re) = 3467.049(3) MHz. The quadrupole coupling strengths are eQq( 187Re) = 716.55(2) MHz and eQq( 185Re) = 757.19(3) MHz. Transitions were also observed for 13C isotopomers and 18O isotopomers. The value for the ReC bond length obtained from a Kraitchman analysis is R( ReC) = 2.080 Å. The rhenium quadrupole coupling strengths are about 20% smaller than those obtained for HRe(CO) 5.

  7. 120-mm supercondcting quadrupole for interaction regions of hadron colliders

    SciTech Connect

    Zlobin, A.V.; Kashikhin, V.V.; Mokhov, N.V.; Novitski, I.; /Fermilab

    2010-05-01

    Magnetic and mechanical designs of a Nb{sub 3}Sn quadrupole magnet with 120-mm aperture suitable for interaction regions of hadron colliders are presented. The magnet is based on a two-layer shell-type coil and a cold iron yoke. Special spacers made of a low-Z material are implemented in the coil mid-planes to reduce the level of radiation heat deposition and radiation dose in the coil. The quadrupole mechanical structure is based on aluminum collars supported by an iron yoke and a stainless steel skin. Magnet parameters including maximum field gradient and field harmonics, Nb3Sn coil pre-stress and protection at the operating temperatures of 4.5 and 1.9 K are reported. The level and distribution of radiation heat deposition in the coil and other magnet components are discussed.

  8. 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.

  9. 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.

  10. Beta function measurement in the Tevatron using quadrupole gradient modulation

    SciTech Connect

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

    2005-05-01

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

  11. SKEW QUADRUPOLES IN RHIC DIPOLE MAGNETS AT HIGH FIELDS.

    SciTech Connect

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

    1995-06-11

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

  12. Skew quadrupole in RHIC dipole magnets at high fields

    SciTech Connect

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

    1995-07-01

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

  13. Development and test of LARP technological quadrupole (TQC) magnet

    SciTech Connect

    Feher, S.; Bossert, R.C.; Ambrosio, G.; Andreev, N.; Barzi, E.; Carcagno, R.; Kashikhin, V.S.; Kashikhin, V.V.; Lamm, M.J.; Nobrega, F.; Novitski, I.; /Fermilab /LBL, Berkeley

    2006-08-01

    In support of the development of a large-aperture Nb{sub 3}Sn superconducting quadrupole for the Large Hadron Collider (LHC) luminosity upgrade, two-layer quadrupole models (TQC and TQS) with 90-mm aperture are being constructed at Fermilab and LBNL within the framework of the US LHC Accelerator Research Program (LARP). This paper describes the construction and test of model TQC01. ANSYS calculations of the structure are compared with measurements during construction. Fabrication experience is described and in-process measurements are reported. Test results at 4.5K are presented, including magnet training, current ramp rate studies and magnet quench current . Results of magnetic measurements at helium temperature are also presented.

  14. Development and Test of LARP Technological Quadrupole (TQC) Magnet

    SciTech Connect

    Feher, S.; Bossert, R.C.; Ambrosio, G.; Andreev, N.; Barzi, E.; Carcagno, R.; Kashikhin, V.S.; Kashikhin, V.V.; Lamm, M.J.; Nobrega, F.; Novitski, I.; Pischalnikov, Yu.; Sylvester, C.; Tartaglia, M.; Turrioni, D.; Whitson, G.; Yamada, R.; Zlobin, A.V.; Caspi, S.; Dietderich, D.; Ferracin, P.; Hannaford, R.; Hafalia, A.R.; Sabbi, G.

    2007-06-01

    In support of the development of a large-aperture Nb{sub 3}Sn superconducting quadrupole for the Large Hadron Collider (LHC) luminosity upgrade, two-layer quadrupole models (TQC and TQS) with 90 mm aperture are being constructed at Fermilab and LBNL within the framework of the US LHC Accelerator Research Program (LARP). This paper describes the construction and test of model TQC01. ANSYS calculations of the structure are compared with measurements during construction. Fabrication experience is described and in-process measurements are reported. Test results at 4.5 K are presented, including magnet training, current ramp rate studies and magnet quench current. Results of magnetic measurements at helium temperature are also presented.

  15. Theoretical study of the radiative capture reactions {sup 2}H(n,{gamma}){sup 3}H and {sup 2}H(p,{gamma}){sup 3}He at low energies

    SciTech Connect

    M. Viviani; R. Schiavilla; A. Kievsky

    1996-02-01

    Correlated Hyperspherical Harmonics wave functions with {Delta}-isobar admixtures obtained from realistic interactions are used to study the thermal neutron radiative capture on deuterium, and the {sup 2}H({rvec p},{gamma}){sup 3}He and p({rvec d},{gamma}){sup 3}He reactions in the center of mass energy range 0-100 keV. The nuclear electromagnetic current includes one and two-body components. Results for the {sup 2}H({rvec d},{gamma}){sup 3}H cross section and photon polarization parameter, as well as for the energy dependence of the astrophysical factor and angular distributions of the differential cross section, vector and tensor analyzing powers, and photon linear polarization coefficient of the {sup 2}H({rvec p},{gamma}){sup 3}He and p({rvec d},{gamma}){sup 3}He reactions are reported. Large effects due to two-body currents, in particular the long-range ones associated with the tensor component of the nucleon-nucleon interaction, are observed in the photon polarization parameter and vector analyzing power. Good, quantitative agreement between theory and experiment is found for all observables, with the exception of the vector analyzing power for which the calculated values underestimate the data by about 30%.

  16. Environmental, trophic, and ecological factors influencing bone collagen δ2H

    NASA Astrophysics Data System (ADS)

    Topalov, Katarina; Schimmelmann, Arndt; David Polly, P.; Sauer, Peter E.; Lowry, Mark

    2013-06-01

    Organic deuterium/hydrogen stable isotope ratios (i.e., 2H/1H, expressed as δ2H value in ‰) in animal tissues are related to the 2H/1H in diet and ingested water. Bone collagen preserves the biochemical 2H/1H isotopic signal in the δ2H value of collagen's non-exchangeable hydrogen. Therefore, δ2H preserved in bone collagen has the potential to constrain environmental and trophic conditions, which is of interest to researchers studying of both living and fossil vertebrates. Our data examine the relationship of δ2H values of collagen with geographic variation in δ2H of meteoric waters, with local variations in the ecology and trophic level of species, and with the transition from mother's milk to adult diet. Based on 97 individuals from 22 marine and terrestrial vertebrates (predominately mammals), we found the relationships of collagen δ2H to both geographic variation in meteoric water δ2H (R2 = 0.55) and to δ15N in bone collagen (R2 = 0.17) statistically significant but weaker than previously reported. The second strongest control on collagen δ2H in our data is dietary, with nearly 50 percent of the variance in δ2H explained by trophic level (R2 = 0.47). Trophic level effects potentially confound the local meteoric signal if not held constant: herbivores tend to have the lowest δ2H values, omnivores have intermediate ones, and carnivores have the highest values. Body size (most likely related to mass-specific metabolic rates) has a strong influence on collagen δ2H (R2 = 0.30), by causing greater sensitivity in smaller animals to seasonal climate variations and/or high evapotranspiration leading to 2H-enrichment in tissues. In marine mammals weaning produces a dramatic effect on collagen δ2H with adult values being universally higher than pup values (R2 = 0.79). Interestingly, the shift in δ15N at weaning is downward, even though normally hydrogen and nitrogen isotope ratios are positively correlated with one another in respect to trophic level. Our

  17. Isotope Substitution Effect in Polyatomic Molecules on the Example of 13C2H4 ← 12C2H4 Substitution

    NASA Astrophysics Data System (ADS)

    Bekhtereva, E. S.; Gromova, O. V.; Berezkin, K. B.; Kashirina, N. V.; Konov, I. A.; Bauerecker, S.

    2016-03-01

    General points of the theory of isotope substitution are applied to an analysis of the isotope substitution effect for the substitution 13C2H4←12C2H4 in the ethylene molecule. On the basis of the isotope relations so obtained, numerical predictions of band centers and the most significant rotational, centrifugal, and resonance parameters are made here for the first time for the four lower vibrational states of the 13C2H4 molecule, which can be used to analyze the complicated vibrational-rotational structure of the above-mentioned vibrational states.

  18. Thomas-Reiche-Khun populations in X-CH 3 and X-C 2H 5 series of molecules

    NASA Astrophysics Data System (ADS)

    Zitto, M. E.; Caputo, M. C.; Ferraro, M. B.; Lazzeretti, P.

    2000-09-01

    Calculations of nuclear electric shieldings, equivalent to dipole moment geometric derivatives, and related to atomic polar tensors, are presented for X-CH 3 and X-C 2H 5 molecules with X=NH 2, OH and F. The electric shielding tensors satisfy a constraint for the electrostatic equilibrium, i.e., the mixed length-acceleration Thomas-Reiche-Khun sum rule, which gives important indications on the reliability of theoretical predictions of IR intensities and leads to the definition of atomic populations. Numerical evidence was found for the additivity and transferability of atomic populations, within the X-substituted alkane series.

  19. Plane-wave and common-translation-factor treatments of He sup 2+ +H collisions at high velocities

    SciTech Connect

    Errea, L.F. ); Harel, C.; Jouin, H. ); Maidagan, J.M.; Mendez, L. ); Pons, B. ); Riera, A. )

    1992-11-01

    We complement previous work that showed that the molecular approach, modified with plane-wave translation factors, is able to reproduce the fall of charge-exchange cross sections in He{sup 2+}+H collisions, by presenting the molecular data, and studying the corresponding mechanism. We test the accuracy of simplifications of the method that have been employed in the literature, and that lead to very simple calculations. We show that the common-translation-factor method is also successful at high nuclear velocities, provided that sufficiently excited states are included in the basis; moreover, it yields a simple picture of the mechanism and a description of ionization processes at high velocities.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Design and Measurement of the NSLS II Quadrupole Prototypes

    SciTech Connect

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

    2009-05-04

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

  5. 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.

  6. MEASURING LOCAL GRADIENT AND SKEW QUADRUPOLE ERRORS IN RHIC IRS.

    SciTech Connect

    CARDONA,J.; PEGGS,S.; PILAT,R.; PTITSYN,V.

    2004-07-05

    The measurement of local linear errors at RHIC interaction regions using an ''action and phase'' analysis of difference orbits has already been presented. This paper evaluates the accuracy of this technique using difference orbits that were taken when known gradient errors and skew quadrupole errors were intentionally introduced. It also presents action and phase analysis of simulated orbits when controlled errors are intentionally placed in a RHIC simulation model.

  7. Probing the aromaticity of the [(HtAc)3(μ2-H)6], [(HtTh)3(μ2-H)6],+, and [(HtPa)3(μ2-H)6] clusters

    NASA Astrophysics Data System (ADS)

    Ramírez-Tagle, Rodrigo; Alvarado-Soto, Leonor; Arratia-Perez, Ramiro; Bast, Radovan; Alvarez-Thon, Luis

    2011-09-01

    In this study we report about the aromaticity of the prototypical [(HtAc)3(μ2-H)6], [(HtTh)3(μ2-H)6]+, and [(HtPa)3(μ2-H)6] clusters via two magnetic criteria: nucleus-independent chemical shifts (NICS) and the magnetically induced current density. All-electron density functional theory calculations were carried out using the two-component zeroth-order regular approach and the four-component Dirac-Coulomb Hamiltonian, including scalar and spin-orbit relativistic effects. Four-component current density maps and the integration of induced ring-current susceptibilities clearly show that the clusters [(HtAc)3(μ2-H)6] and [(HtTh)3(μ2-H)6]+ are non-aromatic whereas [(HtPa)3(μ2-H)6] is anti-aromatic. However, for the thorium cluster we find a discrepancy between the current density plots and the classification through the NICS index. Our results also demonstrate the increasing influence of f orbitals, on bonding and magnetic properties, with increasing atomic number in these clusters. We think that the enhanced electron mobility in [(HtPa)3(μ2-H)6] is due the significant 5f character of its valence shell. Also the participation of f orbitals in bonding is the reason why the protactinium cluster has the shortest bond lengths of the three clusters. This study provides another example showing that the magnetically induced current density approach can give more reliable results than the NICS index.

  8. Probing the aromaticity of the [(H(t)Ac)3(μ2-H)6], [(H(t)Th)3(μ2-H)6],(+), and [(H(t)Pa)3(μ2-H)6] clusters.

    PubMed

    Ramírez-Tagle, Rodrigo; Alvarado-Soto, Leonor; Arratia-Perez, Ramiro; Bast, Radovan; Alvarez-Thon, Luis

    2011-09-14

    In this study we report about the aromaticity of the prototypical [(H(t)Ac)(3)(μ(2)-H)(6)], [(H(t)Th)(3)(μ(2)-H)(6)](+), and [(H(t)Pa)(3)(μ(2)-H)(6)] clusters via two magnetic criteria: nucleus-independent chemical shifts (NICS) and the magnetically induced current density. All-electron density functional theory calculations were carried out using the two-component zeroth-order regular approach and the four-component Dirac-Coulomb Hamiltonian, including scalar and spin-orbit relativistic effects. Four-component current density maps and the integration of induced ring-current susceptibilities clearly show that the clusters [(H(t)Ac)(3)(μ(2)-H)(6)] and [(H(t)Th)(3)(μ(2)-H)(6)](+) are non-aromatic whereas [(H(t)Pa)(3)(μ(2)-H)(6)] is anti-aromatic. However, for the thorium cluster we find a discrepancy between the current density plots and the classification through the NICS index. Our results also demonstrate the increasing influence of f orbitals, on bonding and magnetic properties, with increasing atomic number in these clusters. We think that the enhanced electron mobility in [(H(t)Pa)(3)(μ(2)-H)(6)] is due the significant 5f character of its valence shell. Also the participation of f orbitals in bonding is the reason why the protactinium cluster has the shortest bond lengths of the three clusters. This study provides another example showing that the magnetically induced current density approach can give more reliable results than the NICS index. PMID:21932909

  9. 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.

  10. Quadrupole Magnetic Sorting of Porcine Islets of Langerhans

    PubMed Central

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

    2009-01-01

    Islet transplantation is emerging as a treatment option for selected patients with type 1 diabetes. Inconsistent isolation, purification, and recovery of large numbers of high-quality islets remain substantial impediments to progress in the field. Removing islets as soon as they are liberated from the pancreas during digestion and circumventing the need for density gradient purification is likely to result in substantially increased viable islet yields by minimizing exposure to proteolytic enzymes, reactive oxygen intermediates, and mechanical stress associated with centrifugation. This study capitalized on the hypervascularity of islets compared with acinar tissue to explore their preferential enrichment with magnetic beads to enable immediate separation in a magnetic field utilizing a quadrupole magnetic sorting. The results demonstrate that (1) preferential enrichment of porcine islets is achievable, but homogeneous bead distribution within the pancreas is difficult to achieve with current protocols; (2) greater than 70% of islets in the dissociated pancreatic tissue were recovered by quadrupole magnetic sorting, but their purity was low; and (3) infused islets purified by density gradients and subsequently passed through quadrupole magnetic sorting had similar potency as uninfused islets. These results demonstrate proof of concept and define the steps for implementation of this technology in pig and human islet isolation. PMID:19505179

  11. 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.

  12. The exact calculation of quadrupole sources for some incompressible flows

    NASA Technical Reports Server (NTRS)

    Brentner, Kenneth S.

    1988-01-01

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

  13. Design of the PEP-II Interaction Region Septum Quadrupole

    NASA Astrophysics Data System (ADS)

    Osborn, J.; Tanabe, J.; Yee, D.; Younger, F.

    1997-05-01

    The PEP-II QF2 magnet is one of the final focus quadrupoles for the Low-Energy Ring (LER) and utilizes a septum aperture to accommodate the adjacent High-Energy Ring (HER) beamline. The LER lattice design specification calls for an extremely high field quality for this magnet. A conventional water-cooled copper coil and laminated steel core design was selected to allow adjustment in the excitation. The close proximity between the LER and HER beamlines and the required integrated quadrupole strength result in a moderately high current density septum design. The QF2 magnets are imbedded in a confined region at each end of the BaBar detector, thus requiring a small magnet core cross section. Pole face windings are included in the QF2 design to buck the skew octupole term induced by the solenoidal fringe field that leaks out of the detector. Back-leg windings are included to buck a small dipole component induced by the lack of perfect quadrupole symmetry in this septum design. 2D pole contour optimization and 3D end chamfers are used to minimize harmonic errors; a separate permanent-magnet Harmonic Corrector Ring compensates for remaining field errors. The design methods and approach, 2D and 3D analyses, and the resulting expected magnet performance are described in this paper.

  14. Gas-phase reaction of CeVO5(+) cluster ions with C2H4: the reactivity of cluster bonded peroxides.

    PubMed

    Ma, Jia-Bi; Meng, Jing-Heng; He, Sheng-Gui

    2015-02-21

    Cerium-vanadium oxide cluster cations CeVO5(+) were generated by laser ablation, mass-selected using a quadrupole mass filter, thermalized through collisions with helium atoms, and then reacted with ethene molecules in a linear ion trap reactor. The cluster reactions have been characterized by time-of-flight mass spectrometry and density functional theory calculations. The CeVO5(+) cluster has a closed-shell electronic structure and contains a peroxide (O2(2-)) unit. The cluster bonded O2(2-) species is reactive enough to oxidize a C2H4 molecule to generate C2H4O2 that can be an acetic acid molecule. Atomic oxygen radicals (O(-)˙), superoxide radicals (O2(-)˙), and peroxides are the three common reactive oxygen species. The reactivity of cluster bonded O(-)˙ and O2(-)˙ radicals has been widely studied while the O2(2-) species were generally thought to be much less reactive or inert toward small molecules under thermal collision conditions. This work is among the first to report the reactivity of the peroxide unit on transition metal oxide clusters with hydrocarbon molecules, to the best of our knowledge. PMID:25573178

  15. Strong enhancement of superconductivity at high pressures within the charge-density-wave states of 2 H -TaS2 and 2 H -TaSe2

    NASA Astrophysics Data System (ADS)

    Freitas, D. C.; Rodière, P.; Osorio, M. R.; Navarro-Moratalla, E.; Nemes, N. M.; Tissen, V. G.; Cario, L.; Coronado, E.; García-Hernández, M.; Vieira, S.; Núñez-Regueiro, M.; Suderow, H.

    2016-05-01

    We present measurements of the superconducting and charge-density-wave (CDW) critical temperatures (Tc and TCDW) as a function of pressure in the transition metal dichalchogenides 2 H -TaSe2 and 2 H -TaS2 . Resistance and susceptibility measurements show that Tc increases from temperatures below 1 K up to 8.5 K at 9.5 GPa in 2 H -TaS2 and 8.2 K at 23 GPa in 2 H -TaSe2 . We observe a kink in the pressure dependence of TCDW at about 4 GPa that we attribute to the lock-in transition from incommensurate CDW to commensurate CDW. Above this pressure, the commensurate TCDW slowly decreases, coexisting with superconductivity within our full pressure range.

  16. Tandem-in-space and tandem-in-time mass spectrometry: Triple quadrupoles and quadrupole ion traps

    SciTech Connect

    Johnson, J.V.; Yost, R.A. ); Kelley, P.E.; Bradford, D.C. )

    1990-10-15

    Tandem-in-time and tandem-in-space MS/MS on quadrupole ion trap (ITMS) and triple quadrupole (TQMS) tandem mass spectrometers, respectively, were compared by evaluating the MS/MS daughter spectra, efficiencies of collision-induced dissociation (CID), limits of detection, and dynamic ranges obtained for the methane positive chemical ionization (PCI)-CID of two alkylphosphonates. Although the yield of daughter ions is dependent upon a number of instrumental parameters on both instruments, with judicious selection of parameters the ITMS and TQMS both yielded daughter ions of similar relative abundances. The ITMS had greater efficiencies of fragmentation, collection, and mass selection and transmission of the daughter ions to the detector. With PCI-MS/MS analysis of diisopropyl methylphosphonate standards introduced via capillary gas chromatography, full daughter spectra could be obtained for as little as 15 pg and 1.5 ng injected for the ITMS and the TQMS, respectively.

  17. The role of isovalency in the reactions of the cyano (CN), boron monoxide (BO), silicon nitride (SiN), and ethynyl (C2H) radicals with unsaturated hydrocarbons acetylene (C2H2) and ethylene (C2H4).

    PubMed

    Parker, D S N; Mebel, A M; Kaiser, R I

    2014-04-21

    The classification of chemical reactions based on shared characteristics is at the heart of the chemical sciences, and is well exemplified by Langmuir's concept of isovalency, in which 'two molecular entities with the same number of valence electrons have similar chemistries'. Within this account we further investigate the ramifications of the isovalency of four radicals with the same X(2)Σ(+) electronic structure - cyano (CN), boron monoxide (BO), silicon nitride (SiN), and ethynyl (C2H), and their reactions with simple prototype hydrocarbons acetylene (C2H2) and ethylene (C2H4). The fact that these four reactants own the same X(2)Σ(+) electronic ground state should dictate the outcome of their reactions with prototypical hydrocarbons holding a carbon-carbon triple and double bond. However, we find that other factors come into play, namely, atomic radii, bonding orbital overlaps, and preferential location of the radical site. These doublet radical reactions with simple hydrocarbons play significant roles in extreme environments such as the interstellar medium and planetary atmospheres (CN, SiN and C2H), and combustion flames (C2H, BO). PMID:24418936

  18. Resonances in the reaction ortho- and para- D2 + H at temperatures below 10 K

    NASA Astrophysics Data System (ADS)

    Simbotin, I.; Côté, R.

    2016-05-01

    In a previous study we reported cross sections for the reaction H2 + D in the temperature regime 10-6 < T < 10 K, and found pronounced shape resonances, especially in the p and d partial waves. We found that the resonant structures were sensitive to the initial rovibrational state of H2; in particular, we showed that the effect of the nuclear-spin symmetry was very important, since ortho- and para- H2 gave significantly different results. We now investigate the reaction D2 + H for vibrationally excited ortho- and para- D2, and compare and contrast these results with those for H2 + D. We remark that this benchmark system is a prototypical example of reactions with a strong barrier, which have very small cross sections in the cold and ultracold regimes. However, shape resonances can enhance the reaction cross sections by orders of magnitude for temperatures around and below T = 1 K. Moreover, resonant features would provide stringent tests for quantum chemistry calculations of potential energy surfaces. Partial support from the US Army Research Office (Grant No. W911NF-13-1-0213).

  19. Sepsis does not alter red blood cell glucose metabolism or Na+ concentration: A 2H-, 23Na-NMR study

    SciTech Connect

    Hotchkiss, R.S.; Song, S.K.; Ling, C.S.; Ackerman, J.J.; Karl, I.E. )

    1990-01-01

    The effects of sepsis on intracellular Na+ concentration ((Na+)i) and glucose metabolism were examined in rat red blood cells (RBCs) by using 23Na- and 2H-nuclear magnetic resonance (NMR) spectroscopy. Sepsis was induced in 15 halothane-anesthetized female Sprague-Dawley rats by using the cecal ligation and perforation technique; 14 control rats underwent cecal manipulation without ligation. The animals were fasted for 36 h, but allowed free access to water. At 36 h postsurgery, RBCs were examined by 23Na-NMR by using dysprosium tripolyphosphate as a chemical shift reagent. Human RBCs from 17 critically ill nonseptic patients and from 7 patients who were diagnosed as septic were also examined for (Na+)i. Five rat RBC specimens had (Na+)i determined by both 23Na-NMR and inductively coupled plasma-atomic emission spectroscopy (ICP-AES). For glucose metabolism studies, RBCs from septic and control rats were suspended in modified Krebs-Henseleit buffer containing (6,6-2H2)glucose and examined by 2H-NMR. No significant differences in (Na+)i or glucose utilization were found in RBCs from control or septic rats. There were no differences in (Na+)i in the two groups of patients. The (Na+)i determined by NMR spectroscopy agreed closely with measurements using ICP-AES and establish that 100% of the (Na+)i of the RBC is visible by NMR. Glucose measurements determined by 2H-NMR correlated closely (correlation coefficient = 0.93) with enzymatic analysis. These studies showed no evidence that sepsis disturbed RBC membrane function or metabolism.

  20. Fabrication and tests of 3He and 2H targets for beam polarization measurement

    PubMed

    Naqvi; Aksoy; Nagadi; Al-Ohali; Kidwai; Fageeha

    2000-09-01

    3He and 2H targets were fabricated through implantation of 3He and 2H ions in 0.2-0.3 mm thick tantalum and titanium foils. The energy of 3He and 2H ions was 45-100 and 78 keV, respectively. Ions beams with typical current of 90-300 microA were used for implantation. Stability tests of 3He and 2H targets were carried out by monitoring the yield of 3He(d, p)4He and 2H(d, p)3H reactions. For the 3He target, the reaction yield was stable for both tantalum and titanium foils but the most stabilized maximum yield was observed for the 100 keV tantalum target. In the case of 2H targets, the yield increased with increasing total dose implanted on the target. PMID:10972150

  1. Structure, phase transitions, dielectric and spectroscopic studies of the 2-aminopyrimidinium salts: [(2-NH 2C 4N 2H 3) 2H][ClO 4] and [2-NH 2C 4N 2H 4][BF 4

    NASA Astrophysics Data System (ADS)

    Czupiński, O.; Wojtaś, M.; Ciunik, Z.; Jakubas, R.

    2006-01-01

    Crystal structure of the 2-aminopyrimidinium derivatives: [(2-NH 2C 4N 2H 3) 2H][ClO 4] (I) and [2-NH 2C 4N 2H 4][BF 4] (II) has been determined at 100 K (I) and 293 K (II) by means of single crystal X-ray diffraction as monoclinic space group, P2/c and P2/n, respectively. The asymmetric part of the unit cell of (I) contains two symmetry independent 2-aminopyrimidine forming one dimeric cation and one disordered perchlorate anion. The structure of (II) consists of 2-aminopyrimidinium cation, [2-NH 2C 4N 2H 4] +, protonated at a pyrimidine ring-N atom and [BF 4] - anion. Differential scanning calorimetry (DSC) on perchlorate derivative ( 1:1), [2-NH 2C 4N 2H 3][ClO 4] (III)—being isomorphic to tetrafluoroborate one (I) at room temperature, reveals two phase transitions of first order: at 250/275 K and 390/410 K (cooling-heating, respectively), whereas the analog (II) only one transition at high temperatures—343/385 K. The dielectric studies in the frequency range 75 kHz - 10 MHz disclose relaxation process at high temperatures in salt (I). Infrared spectra of polycrystalline [2-NH 2C 4N 2H 4][BF 4] have been studied in the temperature range 300-420 K. Substantial changes in the temperature evolution of frequencies of internal modes of the 2-aminopyrimidinium cations and [BF 4] - anions near 390 K are due to the variations in the motion of both moieties and hydrogen bond configuration. The experimental studies indicate that all phase transitions taking place in studied 2-aminopyrimidinium derivatives are classified as an order-disorder.

  2. Characterization of the ELIMED Permanent Magnets Quadrupole system prototype with laser-driven proton beams

    NASA Astrophysics Data System (ADS)

    Schillaci, F.; Pommarel, L.; Romano, F.; Cuttone, G.; Costa, M.; Giove, D.; Maggiore, M.; Russo, A. D.; Scuderi, V.; Malka, V.; Vauzour, B.; Flacco, A.; Cirrone, G. A. P.

    2016-07-01

    Laser-based accelerators are gaining interest in recent years as an alternative to conventional machines [1]. In the actual ion acceleration scheme, energy and angular spread of the laser-driven beams are the main limiting factors for beam applications and different solutions for dedicated beam-transport lines have been proposed [2,3]. In this context a system of Permanent Magnet Quadrupoles (PMQs) has been realized [2] by INFN-LNS (Laboratori Nazionali del Sud of the Instituto Nazionale di Fisica Nucleare) researchers, in collaboration with SIGMAPHI company in France, to be used as a collection and pre-selection system for laser driven proton beams. This system is meant to be a prototype to a more performing one [3] to be installed at ELI-Beamlines for the collection of ions. The final system is designed for protons and carbons up to 60 MeV/u. In order to validate the design and the performances of this large bore, compact, high gradient magnetic system prototype an experimental campaign have been carried out, in collaboration with the group of the SAPHIR experimental facility at LOA (Laboratoire d'Optique Appliquée) in Paris using a 200 TW Ti:Sapphire laser system. During this campaign a deep study of the quadrupole system optics has been performed, comparing the results with the simulation codes used to determine the setup of the PMQ system and to track protons with realistic TNSA-like divergence and spectrum. Experimental and simulation results are good agreement, demonstrating the possibility to have a good control on the magnet optics. The procedure used during the experimental campaign and the most relevant results are reported here.

  3. The SNF2H Chromatin Remodeling Enzyme Has Opposing Effects on Cytokine Gene Expression

    PubMed Central

    Precht, Patricia; Wurster, Andrea L.; Pazin, Michael J.

    2010-01-01

    Cytokine gene expression is a key control point in the function of the immune system. Cytokine gene regulation is linked to changes in chromatin structure; however, little is known about the remodeling enzymes mediating these changes. Here we investigated the role of the ATP-dependent chromatin remodeling enzyme SNF2H in mouse T cells; to date, SNF2H has not been investigated in T cells. We found that SNF2H repressed expression of IL-2 and other cytokines in activated cells. By contrast, SNF2H activated expression of IL-3. The ISWI components SNF2H and ACF1 bound to the tested loci, suggesting the regulation was direct. SNF2H decreased accessibility at some binding sites within the IL2 locus, and increased accessibility within some IL3 binding sites. The changes in gene expression positively correlated with accessibility changes, suggesting a simple model that accessibility enables transcription. We also found that loss of the ISWI ATPase SNF2H reduced binding to target genes and protein expression of ACF1, a binding partner for SNF2H, suggesting complex formation stabilized ACF1. Together, these findings reveal a direct role for SNF2H in both repression and activation of cytokine genes. PMID:20471682

  4. Chemical behavior of the gas-phase pentacoordinated carbonium ion, C2H+7

    NASA Astrophysics Data System (ADS)

    Heck, Albert J. R.; de Koning, Leo J.; Nibbering, Nico M. M.

    1992-09-01

    The uni- and bimolecular chemistry of C2H+7 ions have been studied in the gas phase using the methods of sector and Fourier transform ion cyclotron resonance mass spectrometry. Unimolecular decomposition of the C2H+7 ions predominantly shows the elimination of a hydrogen molecule which proceeds without a significant kinetic energy release. However, the elimination of a hydrogen molecule is found to suffer from a very large isotope effect, which has been rationalized by the difference in Gibbs free energy change for H2, HD and D2 loss from the various isotopomers of protonated ethane. In general, long-lived C2H+7 ions can be generated either by proton transfer to ethane, methyl cation transfer to methane or by association of C2H+5 and H2. Conversely, C2H+7 ions can react as a proton or a methyl cation donor, or eliminate an H2 molecule. In contrast to CH+5, C2H+7 displays an ambident chemical behavior, which shows a balanced competition between a proton and a methyl cation donor. Both the uni- and bimolecular reactivity of C2H+7 reveal that the proton accepted in an exothermic protonation of ethane randomizes with the original hydrogen atoms of ethane. This intramolecular randomization is found to be a very fast process which precedes decomposition of the metastable C2H+7 ions as well as the bimolecular processes of the long-lived C2H+7 ions.

  5. Equilibrium of non-neutral plasmas in a Malmberg-Penning trap with quadrupole field errors

    NASA Astrophysics Data System (ADS)

    Akhmetov, Timur; Kotelnikov, Igor

    2009-12-01

    The effect of small quadrupole magnetic and electrostatic perturbations on the equilibrium of a non-neutral plasma confined in a Malmberg-Penning trap is analyzed on the base of the parallel current constraint derived recently [Kotelnikov and Romé, Phys. Plasmas 15, 072118 (2008)]. The constraint is generalized to the case of nonuniform plasma temperature. Analytical solutions for the electric potential variations inside the trap and Pfirsch-Schlüter currents are found in the paraxial limit for stepwise radial density profiles of the plasma. It is shown that the equilibrium distorted by a magnetic quadrupole is qualitatively different from that perturbed by an electric quadrupole. In particular, a magnetic quadrupole squeeze perturbs the plasma potential only within a localized region, whereas an electric quadrupole squeeze perturbs the potential in the entire plasma column. On the other hand, axially variable parts of the perturbed potential have similar radial profiles for both electric and magnetic quadrupoles.

  6. Equilibrium of non-neutral plasmas in a Malmberg-Penning trap with quadrupole field errors

    SciTech Connect

    Akhmetov, Timur; Kotelnikov, Igor

    2009-12-15

    The effect of small quadrupole magnetic and electrostatic perturbations on the equilibrium of a non-neutral plasma confined in a Malmberg-Penning trap is analyzed on the base of the parallel current constraint derived recently [Kotelnikov and Rome, Phys. Plasmas 15, 072118 (2008)]. The constraint is generalized to the case of nonuniform plasma temperature. Analytical solutions for the electric potential variations inside the trap and Pfirsch-Schlueter currents are found in the paraxial limit for stepwise radial density profiles of the plasma. It is shown that the equilibrium distorted by a magnetic quadrupole is qualitatively different from that perturbed by an electric quadrupole. In particular, a magnetic quadrupole squeeze perturbs the plasma potential only within a localized region, whereas an electric quadrupole squeeze perturbs the potential in the entire plasma column. On the other hand, axially variable parts of the perturbed potential have similar radial profiles for both electric and magnetic quadrupoles.

  7. Testing of NB3SN Quadrupole Coils Using Magnetic Mirror Structure

    NASA Astrophysics Data System (ADS)

    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.

    2010-04-01

    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 Nb3Sn 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.

  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. Calculational and Experimental Investigations of the Pressure Effects on Radical - Radical Cross Combinations Reactions: C2H5 + C2H3

    NASA Technical Reports Server (NTRS)

    Fahr, Askar; Halpern, Joshua B.; Tardy, Dwight C.

    2007-01-01

    Pressure-dependent product yields have been experimentally determined for the cross-radical reaction C2H5 + C2H3. These results have been extended by calculations. It is shown that the chemically activated combination adduct, 1-C4H8*, is either stabilized by bimolecular collisions or subject to a variety of unimolecular reactions including cyclizations and decompositions. Therefore the "apparent" combination/disproportionation ratio exhibits a complex pressure dependence. The experimental studies were performed at 298 K and at selected pressures between about 4 Torr (0.5 kPa) and 760 Torr (101 kPa). Ethyl and vinyl radicals were simultaneously produced by 193 nm excimer laser photolysis of C2H5COC2H3 or photolysis of C2H3Br and C2H5COC2H5. Gas chromatograph/mass spectrometry/flame ionization detection (GC/MS/FID) were used to identify and quantify the final reaction products. The major combination reactions at pressures between 500 (66.5 kPa) and 760 Torr are (1c) C2H5 + C2H3 yields 1-butene, (2c) C2H5 + C2H5 yields n-butane, and (3c) C2H3 + C2H3 yields 1,3-butadiene. The major products of the disproportionation reactions are ethane, ethylene, and acetylene. At moderate and lower pressures, secondary products, including propene, propane, isobutene, 2-butene (cis and trans), 1-pentene, 1,4-pentadiene, and 1,5-hexadiene are also observed. Two isomers of C4H6, cyclobutene and/or 1,2-butadiene, were also among the likely products. The pressure-dependent yield of the cross-combination product, 1-butene, was compared to the yield of n-butane, the combination product of reaction (2c), which was found to be independent of pressure over the range of this study. The [ 1-C4H8]/[C4H10] ratio was reduced from approx.1.2 at 760 Torr (101 kPa) to approx.0.5 at 100 Torr (13.3 kPa) and approx.0.1 at pressures lower than about 5 Torr (approx.0.7 kPa). Electronic structure and RRKM calculations were used to simulate both unimolecular and bimolecular processes. The relative importance

  10. 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.

  11. 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.

  12. 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.

  13. Progress in the Development of Superconducting Quadrupoles forHeavy-ion Fusion

    SciTech Connect

    Faltens, A.; Lietzke, A.; Sabbi, G.; Seidl, P.; Lund, S.; Manahan, R.; Martovetsky, N.; Gung, C.; Minervini, J.; Schultz, J.; Myatt, L.; Meinke, R.

    2002-08-19

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

    SciTech Connect

    Cai, Yunhai

    1999-03-09

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

  15. Comparison of conventional and novel quadrupole drift tube magnets inspired by Klaus Halbach

    SciTech Connect

    Feinberg, B.

    1995-02-01

    Quadrupole drift tube magnets for a heavy-ion linac provide a demanding application of magnet technology. A comparison is made of three different solutions to the problem of providing an adjustable high-field-strength quadrupole magnet in a small volume. A conventional tape-wound electromagnet quadrupole magnet (conventional) is compared with an adjustable permanent-magnet/iron quadrupole magnet (hybrid) and a laced permanent-magnet/iron/electromagnet (laced). Data is presented from magnets constructed for the SuperHILAC heavy-ion linear accelerator, and conclusions are drawn for various applications.

  16. 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.

  17. 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.

  18. Beam acceleration through proton radio frequency quadrupole accelerator in BARC

    NASA Astrophysics Data System (ADS)

    Bhagwat, P. V.; Krishnagopal, S.; Mathew, J. V.; Singh, S. K.; Jain, P.; Rao, S. V. L. S.; Pande, M.; Kumar, R.; Roychowdhury, P.; Kelwani, H.; Rama Rao, B. V.; Gupta, S. K.; Agarwal, A.; Kukreti, B. M.; Singh, P.

    2016-05-01

    A 3 MeV proton Radio Frequency Quadrupole (RFQ) accelerator has been designed at the Bhabha Atomic Research Centre, Mumbai, India, for the Low Energy High Intensity Proton Accelerator (LEHIPA) programme. The 352 MHz RFQ is built in 4 segments and in the first phase two segments of the LEHIPA RFQ were commissioned, accelerating a 50 keV, 1 mA pulsed proton beam from the ion source, to an energy of 1.24 MeV. The successful operation of the RFQ gave confidence in the physics understanding and technology development that have been achieved, and indicate that the road forward can now be traversed rather more quickly.

  19. Magnetic quadrupole doublet focusing system for high energy ions.

    PubMed

    Glass, Gary A; Dymnikov, Alexander D; Rout, Bibhudutta; Dias, Johnny F; Houston, Louis M; LeBlanc, Jared

    2008-03-01

    A high energy focused ion beam microprobe using a doublet arrangement of short magnetic quadrupole lenses was used to focus 1-3 MeV protons to spot sizes of 1x1 microm2 and 1-4.5 MeV carbon and silicon ion beams to spot sizes of 1.5x1.5 microm2. The results presented clearly demonstrate that this simple doublet configuration can provide high energy microbeams for microanalysis and microfabrication applications. PMID:18377047

  20. 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.

  1. 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.

  2. Computational Analysis of Quadrupole Mass Filters Employing Nontraditional Waveforms

    NASA Astrophysics Data System (ADS)

    Brabeck, Gregory F.; Reilly, Peter T. A.

    2016-06-01

    Quadrupole mass filters using non-sinusoidal driving potentials present exciting opportunities for new functionality. Predicting figures of merit like resolving power and transmission efficiency helps characterize these emerging devices. To this end, matrix methods of solving the Hill equation of ion motion are employed to calculate stability diagrams and pseudopotential well depth maps in the a,q plane for arbitrary waveforms. The theoretical resolving power and well depth of digital, trapezoidal and sinusoidal mass filters are compared. Simplified expressions for digital mass filter operation are presented.

  3. 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.

  4. Computational Analysis of Quadrupole Mass Filters Employing Nontraditional Waveforms.

    PubMed

    Brabeck, Gregory F; Reilly, Peter T A

    2016-06-01

    Quadrupole mass filters using non-sinusoidal driving potentials present exciting opportunities for new functionality. Predicting figures of merit like resolving power and transmission efficiency helps characterize these emerging devices. To this end, matrix methods of solving the Hill equation of ion motion are employed to calculate stability diagrams and pseudopotential well depth maps in the a,q plane for arbitrary waveforms. The theoretical resolving power and well depth of digital, trapezoidal and sinusoidal mass filters are compared. Simplified expressions for digital mass filter operation are presented. Graphical Abstract ᅟ. PMID:27091594

  5. Advances in the engineering of quadrupole resonance landmine detection systems

    NASA Astrophysics Data System (ADS)

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

    2005-06-01

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

  6. Operational aspects of the Main Injector large aperture quadrupole (WQB)

    SciTech Connect

    Chou, W.; Bartelson, L.; Brown, B.; Capista, D.; Crisp, J.; DiMarco, J.; Fitzgerald, J.; Glass, H.; Harding, D.; Johnson, D.; Kashikhin, V.; /Fermilab

    2007-06-01

    A two-year Large Aperture Quadrupole (WQB) Project was completed in the summer of 2006 at Fermilab. [1] Nine WQBs were designed, fabricated and bench-tested by the Technical Division. Seven of them were installed in the Main Injector and the other two for spares. They perform well. The aperture increase meets the design goal and the perturbation to the lattice is minimal. The machine acceptance in the injection and extraction regions is increased from 40{pi} to 60{pi} mm-mrad. This paper gives a brief report of the operation and performance of these magnets. Details can be found in Ref [2].

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

    DOEpatents

    Felter, Thomas E.

    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.

  8. 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.

  9. Non-interacting Fermi gas in a magnetic quadrupole trap

    NASA Astrophysics Data System (ADS)

    Lau, To Chun Johnathan; Goulko, Olga; Chevy, Frédéric; Lobo, Carlos

    2014-05-01

    A non-interacting gas of spin polarised 6Li Fermi gas in a magnetic quadrupole trap which is not in thermal equilibrium can nevertheless show thermal signatures in some cases. This puzzling behaviour can be seen by measuring the doubly integrated momentum distribution along a particular axis. This distribution can be extremely close to a Gaussian from which we can extract a temperature. However, we show, using molecular dynamics simulations that the temperature thus measured is generally different along different axes. We provide a general explanation of this phenomenon based on ergodicity and check it with further simulations.

  10. Uranium isotope measurements by quadrupole ICP-MS for process monitoring of enrichment

    SciTech Connect

    Policke, T.A.; Bolin, R.N.; Harris, T.L.

    1998-12-31

    Historically, uranium isotopic ratio measurements in the nuclear industry have been performed using Thermal Ionization Mass Spectrometry (TIMS); primarily due to the high level of precision that can be achieved. TIMS analysis, however, requires sample purification and intricate sample loading. Quadrupole (low resolution, single detector) inductively coupled plasma--mass spectrometry, Q-ICP-MS, overcomes these disadvantages and is a cost-effective alternative, i.e., in terms of initial capital, maintenance, and operating costs. This paper presents a simple, single standard approach for measuring uranium isotope content in various solid and liquid nuclear materials along with some comparison data of Q-ICP-MS and TIMS. Intensity ratios of {sup 234}U, {sup 235}U, {sup 236}U, and {sup 238}U to total U intensity are produced, providing the enrichment level or percent {sup 235}U. A detailed description of the instrument and data collection parameters are also provided. Optimal precision and accuracy are achieved through the use of a single standard which is closely matched to the enrichment and concentration of the samples. Depending upon the standard chosen, enrichments between depleted and 97% can be quantified. Standard deviations for the major uranium isotopes are typically within 0.02 absolute and at least an order of magnitude lower for the minor U isotope abundances.

  11. Friction in nuclear dynamics

    SciTech Connect

    Swiatecki, W.J.

    1985-03-01

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

  12. Analysis Of 2H-Evaporator Scale Wall [HTF-13-82] And Pot Bottom [HTF-13-77] Samples

    SciTech Connect

    Oji, L. N.

    2013-09-11

    Savannah River Remediation (SRR) is planning to remove a buildup of sodium aluminosilicate scale from the 2H-evaporator pot by loading and soaking the pot with heated 1.5 M nitric acid solution. Sampling and analysis of the scale material has been performed so that uranium and plutonium isotopic analysis can be input into a Nuclear Criticality Safety Assessment (NCSA) for scale removal by chemical cleaning. Historically, since the operation of the Defense Waste Processing Facility (DWPF), silicon in the DWPF recycle stream combines with aluminum in the typical tank farm supernate to form sodium aluminosilicate scale mineral deposits in the 2H-evaporator pot and gravity drain line. The 2H-evaporator scale samples analyzed by Savannah River National Laboratory (SRNL) came from two different locations within the evaporator pot; the bottom cone sections of the 2H-evaporator pot [Sample HTF-13-77] and the wall 2H-evaporator [sample HTF-13-82]. X-ray diffraction analysis (XRD) confirmed that both the 2H-evaporator pot scale and the wall samples consist of nitrated cancrinite (a crystalline sodium aluminosilicate solid) and clarkeite (a uranium oxyhydroxide mineral). On ''as received'' basis, the bottom pot section scale sample contained an average of 2.59E+00 {+-} 1.40E-01 wt % total uranium with a U-235 enrichment of 6.12E-01 {+-} 1.48E-02 %, while the wall sample contained an average of 4.03E+00 {+-} 9.79E-01 wt % total uranium with a U-235 enrichment of 6.03E-01% {+-} 1.66E-02 wt %. The bottom pot section scale sample analyses results for Pu-238, Pu-239, and Pu-241 are 3.16E-05 {+-} 5.40E-06 wt %, 3.28E-04 {+-} 1.45E-05 wt %, and <8.80E-07 wt %, respectively. The evaporator wall scale samples analysis values for Pu-238, Pu-239, and Pu-241 averages 3.74E-05 {+-} 6.01E-06 wt %, 4.38E-04 {+-} 5.08E-05 wt %, and <1.38E-06 wt %, respectively. The Pu-241 analyses results, as presented, are upper limit values. For these two evaporator scale samples obtained at two different

  13. 77 FR 74283 - Clearing Requirement Determination Under Section 2(h) of the CEA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-13

    ...\\ Clearing Requirement Determination Under Section 2(h) of the CEA; Proposed Rule, 77 FR 47170 (Aug. 7, 2012... to Trade Under Section 2(h)(8) of the Commodity Exchange Act, 76 FR 77728 (Dec. 14, 2011). Clearing... FR 44464 (July 26, 2011); 17 CFR 39.5. The determinations and rules adopted in this release...

  14. Conversion of erythro-D-sphinganine to its (1-/sup 2/H/sub 1/) and (1-/sup 3/H/sub 1/) derivatives

    SciTech Connect

    Crossman, M.W.; Hirschberg, C.B.

    1984-07-01

    A convenient chemical synthesis of erythro-D-(1-2H1) sphinganine and erythro-D-(1-3H1)sphinganine is described. The approach utilizes a stereospecific starting material (natural sphinganine prepared from bovine brain sphingomyelin) and applies a sequence of selective protection of functional groups yielding 2-acetamido-3-O-benzoyloctadecan-1-ol. Oxidation of the primary alcohol to an aldehyde followed by NaB2H4 or NaB3H4 reduction and hydrolysis of the protective groups yields erythro-D-(1-2H1)sphinganine or erythro-D-(1-3H1)sphinganine. The synthetic intermediates and isotopically labeled sphinganines are characterized by infrared analysis, 1H-nuclear magnetic resonance, optical rotation, and gas-liquid radiochromatographic and mass spectral fragmentation analyses. The (1-2H1) and (1-3H1) derivatives were obtained with overall yields (and isotope enrichments) of 11% (min. 84 mol% 2H1) and 8% (60 mCi/mmol), respectively.

  15. The transcriptional regulator c2h2 accelerates mushroom formation in Agaricus bisporus.

    PubMed

    Pelkmans, Jordi F; Vos, Aurin M; Scholtmeijer, Karin; Hendrix, Ed; Baars, Johan J P; Gehrmann, Thies; Reinders, Marcel J T; Lugones, Luis G; Wösten, Han A B

    2016-08-01

    The Cys2His2 zinc finger protein gene c2h2 of Schizophyllum commune is involved in mushroom formation. Its inactivation results in a strain that is arrested at the stage of aggregate formation. In this study, the c2h2 orthologue of Agaricus bisporus was over-expressed in this white button mushroom forming basidiomycete using Agrobacterium-mediated transformation. Morphology, cap expansion rate, and total number and biomass of mushrooms were not affected by over-expression of c2h2. However, yield per day of the c2h2 over-expression strains peaked 1 day earlier. These data and expression analysis indicate that C2H2 impacts timing of mushroom formation at an early stage of development, making its encoding gene a target for breeding of commercial mushroom strains. PMID:27207144

  16. Natural abundance high-resolution solid state 2 H NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Aliev, Abil E.; Harris, Kenneth D. M.; Apperley, David C.

    1994-08-01

    We report for the first time an approach for natural abundance solid state 2 H NMR spectroscopy involving magic angle sample spinning (MAS), high-power 1 H decoupling (HPPD) and 1 H- 2 H cross polarization (CP). Taking tetrakis(trimethylsilyl)silane (TTMSS), adamantane, 1-chloroadamantane, hexamethylbenzene (HMB), 2,2-dimethyl-1,3-propanediol (DMPD) and 2-hydroxymethyl-2-methyl-1,3-propanediol (HMPD) as examples, it has been shown that the combination of HPPD and MAS can be applied readily to study rotator phase solids, allowing isotropic peaks arising from chemically inequivalent 2 H nuclei to be resolved. For natural abundance samples of TTMSS and chloroadamantane, it has been shown that 2 H CP/HPPD/MAS NMR experiments, involving polarization transfer from 1 H to 2 H, may provide considerable sensitivity enhancement in comparison with single pulse experiments.

  17. Natural abundance high-resolution solid state 2 H NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Aliev, Abil E.; Harris, Kenneth D. M.; Apperley, David C.

    1994-08-01

    We report for the first time an approach for natural abundance solid state 2H NMR spectroscopy involving magic angle sample spinning (MAS), high-power 1H decoupling (HPPD) and 1H- 2H cross polarization (CP). Taking tetrakis(trimethylsilyl)silane (TTMSS), adamantane, 1-chloroadamantane, hexamethylbenzene (HMB), 2,2-dimethyl-1,3-propanediol (DMPD) and 2-hydroxymethyl-2-methyl-1,3-propanediol (HMPD) as examples, it has been shown that the combination of HPPD and MAS can be applied readily to study rotator phase solids, allowing isotropic peaks arising from chemically inequivalent 2H nuclei to be resolved. For natural abundance samples of TTMSS and chloroadamantane, it has been shown that 2H CP/HPPD/MAS NMR experiments, involving polarization transfer from 1H to 2H, may provide considerable sensitivity enhancement in comparison with single pulse experiments.

  18. Bi(OTf)3-catalyzed addition of isocyanides to 2H-chromene acetals: an efficient pathway for accessing 2-carboxamide-2H-chromenes.

    PubMed

    Lyu, Longyun; Jin, Ming Yu; He, Qijie; Xie, Han; Bian, Zhaoxiang; Wang, Jun

    2016-09-14

    Bismuth triflate (Bi(OTf)3) is identified as an efficient catalyst for the direct addition of isocyanides to 2H-chromene acetals. The large scope of isocyanides and chromene acetals makes them suitable substrates in this catalytic system. By this synthetic strategy, a polyfunctional molecular scaffold, 2-carboxamide-2H-chromenes could be prepared efficiently in one step up to 95% yield. In addition, this efficient and practical protocol proceeded smoothly in the gram scale even when the catalytic loading was reduced to 2 mol%. PMID:27503764

  19. (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

  20. Hydrogen bridging in the compounds X2H (X=Al,Si,P,S)

    NASA Astrophysics Data System (ADS)

    Owens, Zachary T.; Larkin, Joseph D.; Schaefer, Henry F.

    2006-10-01

    X2H hydrides (X =Al, Si, P, and S) have been investigated using coupled cluster theory with single, double, and triple excitations, the latter incorporated as a perturbative correction [CCSD(T)]. These were performed utilizing a series of correlation-consistent basis sets augmented with diffuse functions (aug-cc-pVXZ, X =D, T, and Q). Al2H and Si2H are determined to have H-bridged C2v structures in their ground states: the Al2H ground state is of B12 symmetry with an Al-H-Al angle of 87.6°, and the Si2H ground state is of A12 symmetry with a Si-H-Si angle of 79.8°. However, P2H and S2H have nonbridged, bent Cs structures: the P2H ground state is of A'2 symmetry with a P-P-H angle of 97.0°, and the S2H ground state is of A'2 symmetry with a S-S-H angle of 93.2°. Ground state geometries, vibrational frequencies, and electron affinities have been computed at all levels of theory. Our CCSD(T)/aug-cc-pVQZ adiabatic electron affinity of 2.34eV for the Si2H radical is in excellent agreement with the photoelectron spectroscopy experiments of Xu et al. [J. Chem. Phys. 108, 7645 (1998)], where the electron affinity was determined to be 2.31±0.01eV.

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

    PubMed

    Soler, Carla; Mañes, Jordi; Picó, Yolanda

    2005-03-01

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

  2. 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.

  3. VIBRATION MEASUREMENTS IN A RHIC QUADRUPOLE AT CRYOGENIC TEMPERATURES.

    SciTech Connect

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

    2005-10-17

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

  4. 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.

  5. 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.

  6. High Reliability Prototype Quadrupole for the Next Linear Collider

    SciTech Connect

    Spencer, Cherrill M

    2001-01-04

    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.

  7. Are liquid chromatography/electrospray tandem quadrupole fragmentation ratios unequivocal confirmation criteria?

    PubMed

    Kaufmann, Anton; Butcher, Patrick; Maden, Kathryn; Widmer, Mirjam; Giles, Kevin; Uría, Diana

    2009-04-01

    Multiple reaction monitoring (MRM) ratios as provided by tandem mass spectrometers are used to confirm positive residue findings (e.g. veterinary drugs or pesticides). The Commission Decision 2002/657/EEC defines tolerance levels for MRM ratios, which are intended to prevent the reporting of false positives. This paper reports findings where blank sample extracts have been spiked by a drug (difloxacin) and the corresponding measured MRM ratios significantly deviated from MRM ratios observed in matrix-free solution. The observation was explained by the formation of two different [M+H](+) analyte ions within the electrospray ionization (ESI) interface. These two ions vary only by the site of analyte protonation. Since they are isobaric, they are equally transmitted through the first quadrupole, but are differently fragmented in the collision chamber. The existence of two isobaric ions was deduced by statistical data and the observation of a doubly charged analyte ion. It was hypothesized that the combined presence of [M+H](+) and [M+2H](2+) implies the existence of two different singly charged ion species differing only by the site of protonation. Low- and high-energy interface-induced fragmentation was performed on the samples. The surviving precursor ion population was mass selected and again fragmented in the collision chamber. Equal product ion spectra would be expected. However, very different product ion spectra were observed for the two interface regimes. This is consistent with the assumption that the two postulated isobaric precursor ions show different stability in the interface. Hence the abundance ratio among the two types of surviving precursor ions will shift and change the resulting product ion spectra. The existence of the postulated singly charged ions with multiple chargeable sites was finally confirmed by successful ion mobility separation. PMID:19241450

  8. Synthesis of [.sup.13C] and [.sup.2H] substituted methacrylic acid, [.sup.13C] and [.sup.2H] substituted methyl methacrylate and/or related compounds

    DOEpatents

    Alvarez, Marc A.; Martinez, Rodolfo A.; Unkefer, Clifford J.

    2008-01-22

    The present invention is directed to labeled compounds of the formulae ##STR00001## wherein Q is selected from the group consisting of --S--, --S(.dbd.O)--, and --S(.dbd.O).sub.2--, Z is selected from the group consisting of 1-naphthyl, substituted 1-naphthyl, 2-naphthyl, substituted 2-naphthyl, and phenyl groups with the structure ##STR00002## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are each independently selected from the group consisting of hydrogen, a C.sub.1-C.sub.4 lower alkyl, a halogen, and an amino group selected from the group consisting of NH.sub.2, NHR and NRR' where R and R' are each independently selected from the group consisting of a C.sub.1-C.sub.4 lower alkyl, an aryl, and an alkoxy group, and X is selected from the group consisting of hydrogen, a C.sub.1-C.sub.4 lower alkyl group, and a fully-deuterated C.sub.1-C.sub.4 lower alkyl group. The present invention is also directed to a process of preparing labeled compounds, e.g., process of preparing [.sup.13C]methacrylic acid by reacting a (CH.sub.3CH.sub.2O--.sup.13C(O)--.sup.13CH.sub.2)-- aryl sulfone precursor with .sup.13CHI to form a (CH.sub.3CH.sub.2O--.sup.13C(O)--.sup.13C(.sup.13CH.sub.3).sub.2)-- aryl sulfone intermediate, and, reacting the (CH.sub.3CH.sub.2O--.sup.13C(O)--.sup.13C(.sup.13CH.sub.3).sub.2)-- aryl sulfone intermediate with sodium hydroxide, followed by acid to form [.sup.13C]methacrylic acid. The present invention is further directed to a process of preparing [.sup.2H.sub.8]methyl methacrylate by reacting a (HOOC--C(C.sup.2H.sub.3).sub.2-- aryl sulfinyl intermediate with CD.sub.3I to form a (.sup.2H.sub.3COOC--C(C.sup.2H.sub.3).sub.2)-- aryl sulfinyl intermediate, and heating the(.sup.2H.sub.3COOC--C(C.sup.2H.sub.3).sub.2)-- aryl sulfinyl intermediate at temperatures and for time sufficient to form [.sup.2H.sub.8]methyl methacrylate.

  9. Absorption of 3(2H)-furanones by human intestinal epithelial Caco-2 cells.

    PubMed

    Stadler, Nicole Christina; Somoza, Veronika; Schwab, Wilfried

    2009-05-13

    A number of 3(2H)-furanones are synthesized by fruits and have been found in cooked foodstuffs, where they impart flavor and odor because of their low perception thresholds. They show genotoxic properties in model studies but are also ranked among the antioxidants and anticarcinogens. This study examined the efficiency of intestinal absorption and metabolic conversion of 3(2H)-furanones by using Caco-2 cell monolayers as an intestinal epithelial cell model. The permeability of each agent was measured in both the apical to basal and basal to apical directions. 2,5-Dimethyl-4-methoxy-3(2H)-furanone (DMMF) showed the highest absorption rate in all experiments, while similar amounts of 4-hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF), 4-hydroxy-2(or 5)-ethyl-5(or 2)-methyl-3(2H)-furanone (HEMF), and 4-hydroxy-5-methyl-3(2H)-furanone (HMF) were taken up. HDMF-glucoside was almost not absorbed but was hydrolyzed to a small extent. The transport of 3(2H)-furanones could not be saturated even at levels of 500 microM and occurred in both directions. Because the uptake was only slightly reduced by apical hyperosmolarity, passive diffusion by paracellular transport is proposed. PMID:19338346

  10. A Ring of C2H in the Protoplanetary Disk Orbiting TW Hya

    NASA Astrophysics Data System (ADS)

    Kastner, Joel H.; Qi, Chunhua; Gorti, Uma; Hily-Blant, Pierre; Forveille, Thierry; Oberg, Karin I.

    2015-01-01

    The circumstellar disk orbiting the nearby (D = 54 pc), ~8 Myr-old, ~0.8 Msun classical T Tauri star TW Hya represents a rich source of information concerning the chemical composition of a protoplanetary disk in its late evolutionary stages, just at or after the epoch of giant planet formation. Following up on the detection of strong mm-wave C2H (4-3) emission from this disk via an unbiased single-dish line survey (Kastner et al. 2014, ApJ, 793, 55), we have used the SMA to image C2H (3-2) at ~1.5" resolution. We find the C2H emission emanates from a relatively narrow ring of inner radius ~1" (~50 AU). We consider various interpretations of this striking, ring-like C2H emission morphology, including whether C2H might serve as a disk "snow line" marker (as is the case for N2H+ Qi et al. 2013, Science, 341, 630) and the possibility that C2H traces particularly efficient photodissociation of hydrocarbons and/or the photoevaporation of small, C-rich grains in this region of the disk.

  11. Direct measurements of rate constants for the reactions of CH3 radicals with C2H6, C2H4, and C2H2 at high temperatures.

    PubMed

    Peukert, S L; Labbe, N J; Sivaramakrishnan, R; Michael, J V

    2013-10-10

    The shock tube technique has been used to study the reactions CH3 + C2H6 → C2H4 + CH4 + H (1), CH3 + C2H4 → Products + H (2), and CH3 + C2H2 → Products + H (3). Biacetyl, (CH3CO)2, was used as a clean high temperature thermal source for CH3-radicals for all the three reactions studied in this work. For reaction 1, the experiments span a T-range of 1153 K ≤ T ≤ 1297 K, at P ~ 0.4 bar. The experiments on reaction 2 cover a T-range of 1176 K ≤ T ≤ 1366 K, at P ~ 1.0 bar, and those on reaction 3 a T-range of 1127 K ≤ T ≤ 1346 K, at P ~ 1.0 bar. Reflected shock tube experiments performed on reactions 1-3, monitored the formation of H-atoms with H-atom Atomic Resonance Absorption Spectrometric (ARAS). Fits to the H-atom temporal profiles using an assembled kinetics model were used to make determinations for k1, k2, and k3. In the case of C2H6, the measurements of [H]-atoms were used to derive direct high-temperature rate constants, k1, that can be represented by the Arrhenius equation k1(T) = 5.41 × 10(-12) exp(-6043 K/T) cm(3) molecules(-1) s(-1) (1153 K ≤ T ≤ 1297 K) for the only bimolecular process that occurs, H-atom abstraction. TST calculations based on ab initio properties calculated at the CCSD(T)/CBS//M06-2X/cc-pVTZ level of theory show excellent agreement, within ±20%, of the measured rate constants. For the reaction of CH3 with C2H4, the present rate constant results, k2', refer to the sum of rate constants, k(2b) + k(2c), from two competing processes, addition-elimination, and the direct abstraction CH3 + C2H4 → C3H6 + H (2b) and CH3 + C2H4 → C2H2 + H + CH4 (2c). Experimental rate constants for k2' can be represented by the Arrhenius equation k2'(T) = 2.18 × 10(-10) exp(-11830 K/T) cm(3) molecules(-1) s(-1) (1176 K ≤ T ≤ 1366 K). The present results are in excellent agreement with recent theoretical predictions. The present study provides the only direct measurement for the high-temperature rate constants for these channels

  12. Optical emission spectroscopy study of premixed C2H4/O2 and C2H4/C2H2/O2 flames for diamond growth with and without CO2 laser excitation

    NASA Astrophysics Data System (ADS)

    He, X. N.; Gebre, T.; Shen, X. K.; Xie, Z. Q.; Zhou, Y. S.; Lu, Y. F.

    2010-02-01

    Optical emission spectroscopy (OES) measurements were carried out to study premixed C2H4/O2 and C2H4/C2H2/O2 combustion flame for diamond deposition with and without a CO2 laser excitation. Strong emissions from radicals C2 and CH were observed in the visible range in all the OES spectra acquired. By adding a continuous-wave CO2 laser to irradiate the flame at a wavelength of 10.591 μm, the common CO2 laser wavelength, it was discovered that the emission intensities of the C2 and CH radicals were increased due to the laser beam induced excitation. OES measurements of the C2 and CH radicals were performed using different gas combinations and laser powers. The rotational temperatures in the flame were determined by analyzing the spectra of the R-branch of the A2Δ-->X2Π (0, 0) electronic transition near 430 nm (CH band head). Information obtained from the OES spectra, including the emission intensities of the C2 and CH radicals, the intensity ratios, and the rotational temperatures, was integrated into the study of diamond deposition on tungsten carbide substrates for mechanism analysis of the laser induced vibrational excitation and laser-assisted diamond deposition.

  13. C(2)H(4): Its Incorporation and Metabolism by Pea Seedlings under Aseptic Conditions.

    PubMed

    Beyer, E M

    1975-08-01

    The effects of various treatments on the recently reported system in pea (Pisum sativum cv. Alaska), which results in (a) the incorporation of (14)C(2)H(4) into the tissue and (b) the conversion of (14)C(2)H(4) to (14)CO(2), was investigated using 2-day-old etiolated seedlings which exhibit a maximum response. Heat treatment (80 C, 1 min) completely inhibited both a and b, whereas homogenization completely inhibited b but only partially inhibited a. Detaching the cotyledons from the root-shoot axis immediately before exposing the detached cotyledons together with the root-shoot axis to (14)C(2)H(4) markedly reduced both a and b. Increasing the (14)C(2)H(4) concentration from 0.14 to over 100 mul/l progressively increased the rate of a and b with tissue incorporation being greater than (14)C(2)H(4) to (14)CO(2) conversion only below 0.3 mul/l (14)C(2)H(4). Reduction of the O(2) concentration reduced both a and b, with over 99% inhibition occurring under anaerobic conditions. The addition of CO(2) (5%) severely inhibited (14)C(2)H(4) to (14)CO(2) conversion without significantly affecting tissue incorporation. Exposure of etiolated seedlings to fluorescent light during (14)C(2)H(4) treatment was without effect. Similarly, indoleacetic acid, gibberellic acid, benzyladenine, abscisic acid, and dibutyryl cyclic adenosine monophosphate had no significant effect on either a or b.The possibilities that the incorporation of (14)C(2)H(4) into pea tissues and its conversion to (14)CO(2) is linked to ethylene action, or that it represents a means of reducing the endogenous ethylene level, are discussed.Several problems encountered with the use of polyethylene vials, rubber serum stoppers, Clorox, and microbial contamination are also described. PMID:16659286

  14. New determination of the {sup 2}H(d,p){sup 3}H and {sup 2}H(d,n){sup 3}He reaction rates at astrophysical energies

    SciTech Connect

    Tumino, A.; Spartà, R.; Spitaleri, C.; Pizzone, R. G.; La Cognata, M.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Mukhamedzhanov, A. M.; Typel, S.; Tognelli, E.; Degl'Innocenti, S.; Prada Moroni, P. G.; Burjan, V.; Kroha, V.; Hons, Z.; Mrazek, J.; Piskor, S.; Lamia, L.

    2014-04-20

    The cross sections of the {sup 2}H(d,p){sup 3}H and {sup 2}H(d,n){sup 3}He reactions have been measured via the Trojan Horse method applied to the quasi-free {sup 2}H({sup 3}He,p {sup 3}H){sup 1}H and {sup 2}H({sup 3}He,n {sup 3}He){sup 1}H processes at 18 MeV off the proton in {sup 3}He. For the first time, the bare nucleus S(E) factors have been determined from 1.5 MeV, across the relevant region for standard Big Bang nucleosynthesis, down to the thermal energies of deuterium burning in the pre-main-sequence (PMS) phase of stellar evolution, as well as of future fusion reactors. Both the energy dependence and the absolute value of the S(E) factors deviate by more than 15% from the available direct data and existing fitting curves, with substantial variations in the electron screening by more than 50%. As a consequence, the reaction rates for astrophysics experience relevant changes, with a maximum increase of up to 20% at the temperatures of the PMS phase. From a recent primordial abundance sensitivity study, it turns out that the {sup 2}H(d,n){sup 3}He reaction is quite influential on {sup 7}Li, and the present change in the reaction rate leads to a decrease in its abundance by up to 10%. The present reaction rates have also been included in an updated version of the FRANEC evolutionary code to analyze their influence on the central deuterium abundance in PMS stars with different masses. The largest variation of about 10%-15% pertains to young stars (≤1 Myr) with masses ≥1 M {sub ☉}.

  15. New Determination of the 2H(d,p)3H and 2H(d,n)3He Reaction Rates at Astrophysical Energies

    NASA Astrophysics Data System (ADS)

    Tumino, A.; Spartà, R.; Spitaleri, C.; Mukhamedzhanov, A. M.; Typel, S.; Pizzone, R. G.; Tognelli, E.; Degl'Innocenti, S.; Burjan, V.; Kroha, V.; Hons, Z.; La Cognata, M.; Lamia, L.; Mrazek, J.; Piskor, S.; Prada Moroni, P. G.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.

    2014-04-01

    The cross sections of the 2H(d,p)3H and 2H(d,n)3He reactions have been measured via the Trojan Horse method applied to the quasi-free 2H(3He,p 3H)1H and 2H(3He,n 3He)1H processes at 18 MeV off the proton in 3He. For the first time, the bare nucleus S(E) factors have been determined from 1.5 MeV, across the relevant region for standard Big Bang nucleosynthesis, down to the thermal energies of deuterium burning in the pre-main-sequence (PMS) phase of stellar evolution, as well as of future fusion reactors. Both the energy dependence and the absolute value of the S(E) factors deviate by more than 15% from the available direct data and existing fitting curves, with substantial variations in the electron screening by more than 50%. As a consequence, the reaction rates for astrophysics experience relevant changes, with a maximum increase of up to 20% at the temperatures of the PMS phase. From a recent primordial abundance sensitivity study, it turns out that the 2H(d,n)3He reaction is quite influential on 7Li, and the present change in the reaction rate leads to a decrease in its abundance by up to 10%. The present reaction rates have also been included in an updated version of the FRANEC evolutionary code to analyze their influence on the central deuterium abundance in PMS stars with different masses. The largest variation of about 10%-15% pertains to young stars (<=1 Myr) with masses >=1 M ⊙.

  16. 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

  17. 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.

  18. Dipole Excitation: A New Method for Mass Analysis with a Quadrupole Mass Filter.

    PubMed

    Konenkov, Nikolai V; Douglas, Donald J; Berdnikov, Alexander S

    2016-07-01

    Trajectory calculations are used to investigate peak shapes and ion transmission with a proposed new method of mass analysis with a quadrupole mass filter. Dipole excitation is applied to either the x or the y electrodes, or both, to create bands of instability within the first stability region. With excitation between the y electrodes (near β y  = 0), ions are removed from the low mass side of a peak, and with ion excitation in x (near β x  = 1), ions are removed from the high mass side. The mass resolution can be approximately doubled with comparatively little loss in ion transmission. Ion motion in an ideal quadrupole field and in the field of a quadrupole constructed with round rods has been studied. With an ideal quadrupole field, excitation in y is found to give better peak shape and resolution than excitation in x. With quadrupoles constructed with round rods, excitation in y is found to remove ions from both the low and high mass sides of a peak. The additional higher order multipoles introduced to the quadrupole potential by the use of round rods couple the x motion to the y motion so that exciting the y motion also excites ions in x. Thus, only excitation in y is necessary. Both with an ideal quadrupole field and quadrupoles constructed with round rods, the resolution can be increased ca. ×2 with little loss of transmission. Graphical Abstract ᅟ. PMID:27026406

  19. Dipole Excitation: A New Method for Mass Analysis with a Quadrupole Mass Filter

    NASA Astrophysics Data System (ADS)

    Konenkov, Nikolai V.; Douglas, Donald J.; Berdnikov, Alexander S.

    2016-07-01

    Trajectory calculations are used to investigate peak shapes and ion transmission with a proposed new method of mass analysis with a quadrupole mass filter. Dipole excitation is applied to either the x or the y electrodes, or both, to create bands of instability within the first stability region. With excitation between the y electrodes (near β y = 0), ions are removed from the low mass side of a peak, and with ion excitation in x (near β x = 1), ions are removed from the high mass side. The mass resolution can be approximately doubled with comparatively little loss in ion transmission. Ion motion in an ideal quadrupole field and in the field of a quadrupole constructed with round rods has been studied. With an ideal quadrupole field, excitation in y is found to give better peak shape and resolution than excitation in x. With quadrupoles constructed with round rods, excitation in y is found to remove ions from both the low and high mass sides of a peak. The additional higher order multipoles introduced to the quadrupole potential by the use of round rods couple the x motion to the y motion so that exciting the y motion also excites ions in x. Thus, only excitation in y is necessary. Both with an ideal quadrupole field and quadrupoles constructed with round rods, the resolution can be increased ca. ×2 with little loss of transmission.

  20. Homotopy Algorithm for Fixed Order Mixed H2/H(infinity) Design

    NASA Technical Reports Server (NTRS)

    Whorton, Mark; Buschek, Harald; Calise, Anthony J.

    1996-01-01

    Recent developments in the field of robust multivariable control have merged the theories of H-infinity and H-2 control. This mixed H-2/H-infinity compensator formulation allows design for nominal performance by H-2 norm minimization while guaranteeing robust stability to unstructured uncertainties by constraining the H-infinity norm. A key difficulty associated with mixed H-2/H-infinity compensation is compensator synthesis. A homotopy algorithm is presented for synthesis of fixed order mixed H-2/H-infinity compensators. Numerical results are presented for a four disk flexible structure to evaluate the efficiency of the algorithm.

  1. Determination of the delta(2H/1H)of Water: RSIL Lab Code 1574

    USGS Publications Warehouse

    Revesz, Kinga; Coplen, Tyler B.

    2008-01-01

    Reston Stable Isotope Laboratory (RSIL) lab code 1574 describes a method used to determine the relative hydrogen isotope-ratio delta(2H,1H), abbreviated hereafter as d2H of water. The d2H measurement of water also is a component of the National Water Quality Laboratory (NWQL) schedules 1142 and 1172. The water is collected unfiltered in a 60-mL glass bottle and capped with a Polyseal cap. In the laboratory, the water sample is equilibrated with gaseous hydrogen using a platinum catalyst (Horita, 1988; Horita and others, 1989; Coplen and others, 1991). The reaction for the exchange of one hydrogen atom is shown in equation 1.

  2. Relative high-resolution absorption cross sections of C2H6 at low temperatures

    NASA Astrophysics Data System (ADS)

    Hargreaves, R. J.; Bernath, P. F.; Appadoo, D. R. T.

    2015-09-01

    Synchrotron radiation has been used to record absorption cross sections of ethane, C2H6, in the far-infrared with very high spectral resolution (up to 0.00096 cm-1). C2H6 is present in the atmospheres of the Gas Giant planets and Titan but the vapor pressure at relevant atmospheric temperatures (i.e., between 70 and 200 K) is low. This makes laboratory measurements difficult. We demonstrate the effectiveness of a unique "enclosive flow" cold cell, located at the Australian Synchrotron, that enables high-resolution absorption cross sections of gaseous C2H6 to be recorded at 90 K.

  3. A practical way to synthesize chiral fluoro-containing polyhydro-2H-chromenes from monoterpenoids

    PubMed Central

    Mikhalchenko, Oksana S; Korchagina, Dina V; Salakhutdinov, Nariman F

    2016-01-01

    Summary Conditions enabling the single-step preparative synthesis of chiral 4-fluoropolyhydro-2H-chromenes in good yields through a reaction between monoterpenoid alcohols with para-menthane skeleton and aldehydes were developed for the first time. The BF3·Et2O/H2O system is used both as a catalyst and as a fluorine source. The reaction can involve aliphatic aldehydes as well as aromatic aldehydes containing various acceptor and donor substituents. 4-Hydroxyhexahydro-2H-chromenes were demonstrated to be capable of converting to 4-fluorohexahydro-2H-chromenes under the developed conditions, the reaction occurs with inversion of configuration. PMID:27340456

  4. Kinetic Resolution of 2H-Azirines by Asymmetric Imine Amidation.

    PubMed

    Hu, Haipeng; Liu, Yangbin; Lin, Lili; Zhang, Yuheng; Liu, Xiaohua; Feng, Xiaoming

    2016-08-16

    Highly efficient kinetic resolution of 2H-azirines by an asymmetric imine amidation was achieved in the presence of a chiral N,N'-dioxide/Sc(III) complex, thus providing a promising method to obtain the enantioenriched 2H-azirine derivatives and protecting-group free aziridines at the same time. It is rare to find an example of N1 of an oxindole participating in a reaction over C3. Moreover, chiral 2H-azirines were stereospecifically transformed into an unprotected aziridine and α-amino ketone. PMID:27384910

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  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)

    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.

  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)

    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.

  12. COMPENSATION OF FAST KICKER ROLLS WITH SKEW QUADRUPOLES

    SciTech Connect

    Pinayev, I.

    2011-03-28

    The development of the third generation light sources lead to the implementation of the top-up operation, when injection occurs while users collect data. The beam excursions due to the non-closure of the injection bump can spoil the data and need to be suppressed. In the horizontal plane compensation can be achieved by adjusting timing and kick amplitudes. The rolls of the kicker magnets create non-closure in the vertical plane and usually there is no means for correction. In the paper we describe proposed compensation scheme utilizing two skew quadrupoles placed inside the injection bump. The third generation light sources implement top-up operation firstly introduced at Advanced Photon Source. In this mode the circulating beam current is supported near constant by frequent injection of small charge, while photon beam is delivered for users. The beam perturbations caused by the mismatched injection bump can provide undesired noise in the user data. Usually the injection trigger is distributed to the users end stations so that those affected would be able to blank data acquisition. Nevertheless, as good operational practice such transients should be suppressed as much as possible. In the horizontal plane (which is commonly used for injection) one can adjust individual kicker strength as well as trigger delay while observing motion of the stored beam centroid. In the vertical plane such means are unavailable in the most cases. The possible solutions include dedicated weak vertical kickers and motorized adjustment of the roll angle of the injection kickers. Both abovementioned approaches are expensive and can significantly deteriorate reliability. We suggest two employ two skew quadrupoles (to correct both angle and position) placed inside the injection bump. In this case the beam position itself serves as measure of the kicker strength (assuming that kickers are well matched) and vertical kicks from the skew quadrupoles will be self synchronized with injection bump

  13. Collisional excitation of doubly and triply deuterated ammonia ND2H and ND3 by H2

    NASA Astrophysics Data System (ADS)

    Daniel, F.; Rist, C.; Faure, A.; Roueff, E.; Gérin, M.; Lis, D. C.; Hily-Blant, P.; Bacmann, A.; Wiesenfeld, L.

    2016-04-01

    The availability of collisional rate coefficients is a prerequisite for an accurate interpretation of astrophysical observations, since the observed media often harbour densities where molecules are populated under non-local thermodynamic equilibrium conditions. In the current study, we present calculations of rate coefficients suitable to describe the various spin isomers of multiply deuterated ammonia, namely the ND2H and ND3 isotopologues. These calculations are based on the most accurate NH3-H2 potential energy surface available, which has been modified to describe the geometrical changes induced by the nuclear substitutions. The dynamical calculations are performed within the close-coupling formalism and are carried out in order to provide rate coefficients up to a temperature of T = 50 K. For the various isotopologues/symmetries, we provide rate coefficients for the energy levels below ˜100 cm-1. Subsequently, these new rate coefficients are used in astrophysical models aimed at reproducing the NH2D, ND2H and ND3 observations previously reported towards the pre-stellar cores B1b and 16293E. We thus update the estimates of the corresponding column densities and find a reasonable agreement with the previous models. In particular, the ortho-to-para ratios of NH2D and NHD2 are found to be consistent with the statistical ratios.

  14. Nuclear moments in covariant density functional theory

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  15. High-resolution spectroscopy of Saturn at 3 microns: CH 4, CH 3D, C 2H 2, C 2H 6, PH 3, clouds, and haze

    NASA Astrophysics Data System (ADS)

    Kim, Joo Hyeon; Kim, Sang J.; Geballe, Thomas R.; Kim, Sungsoo S.; Brown, Linda R.

    2006-12-01

    We report observation and analysis of a high-resolution 2.87-3.54 μm spectrum of the southern temperate region of Saturn obtained with NIRSPEC at Keck II. The spectrum reveals absorption and emission lines of five molecular species as well as spectral features of haze particles. The ν+ν band of CH 3D is detected in absorption between 2.87 and 2.92 μm; and we derived from it a mixing ratio approximately consistent with the Infrared Space Observatory result. The ν band of C 2H 2 also is detected in absorption between 2.95 and 3.05 μm; analysis indicates a sudden drop in the C 2H 2 mixing ratio at 15 mbar (130 km above the 1 bar level), probably due to condensation in the low stratosphere. The presence of the ν+ν+ν band of C 2H 6 near 3.07 μm, first reported by Bjoraker et al. [Bjoraker, G.L., Larson, H.P., Fink, U., 1981. Astrophys. J. 248, 856-862], is confirmed, and a C 2H 6 condensation altitude of 10 mbar (140 km) in the low stratosphere is determined. We assign weak emission lines within the 3.3 μm band of CH 4 to the ν band of C 2H 6, and derive a mixing ratio of 9±4×10 for this species. Most of the C 2H 6 3.3 μm line emission arises in the altitude range 460-620 km (at ˜μbar pressure levels), much higher than the 160-370 km range where the 12 μm thermal molecular line emission of this species arises. At 2.87-2.90 μm the major absorber is tropospheric PH 3. The cloud level determined here and at 3.22-3.54 is 390-460 mbar (˜30 km), somewhat higher than found by Kim and Geballe [Kim, S.J., Geballe, T.R., 2005. Icarus 179, 449-458] from analysis of a low resolution spectrum. A broad absorption feature at 2.96 μm, which might be due to NH 3 ice particles in saturnian clouds, is also present. The effect of a haze layer at about 125 km (˜12 mbar level) on the 3.20-3.54 μm spectrum, which was not apparent in the low resolution spectrum, is clearly evident in the high resolution data, and the spectral properties of the haze particles suggest that

  16. Review of 2H-tetraphenylporphyrins metalation in ultra-high vacuum on metal surfaces

    NASA Astrophysics Data System (ADS)

    Panighel, M.; Di Santo, G.; Caputo, M.; Lal, C.; Taleatu, B.; Goldoni, A.

    2013-12-01

    The formation and conformational adaptation of self-assembled monolayer of 2H-tetraphenylporphyrins (2H-TPPs) on metal surfaces, as well as their metalation processes in ultra-high vacuum (UHV), are reviewed. By means of XPS, NEXAFS and STM measurements we demonstrate that, after the annealing at 550 K, a temperature-induced chemical modification of 2H-TPP monolayer on Ag(111) occurs, resulting in the rotation of the phenyl rings parallel to the substrate plane. Moreover, independently of the conformation, we report three different methods to metalate 2H-TPP monolayers in UHV. Experimental evidence indicates that the presence of a metal atom in the TPP macrocycle influences both the conformation of the molecule and its adsorption distance.

  17. Indirect Approach To The {sup 2}H(d,p){sup 3}H Reaction Study

    SciTech Connect

    Sparta, R.; Pizzone, R. G.; Spitaleri, C.; Cherubini, S.; Crucilla, V.; Gulino, M.; La Cognata, M.; Lamia, L.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Aliotta, M.; Burjan, V.; Hons, Z.; Kroha, V.; Mrazek, J.; Kiss, G.; McCleskey, M.; Trache, L.

    2010-11-24

    In order to understand primordial and stellar nucleosynthesis, we have studied {sup 2}H(d,p){sup 3}H reaction at 0.4 MeV down to astrophysical energies. Knowledge of its S-factor is interesting also to plan reactions for fusion reactors to produce energy. The {sup 2}H(d,p)H reaction has been studied through the Trojan Horse Method applied to the three-body reaction {sup 2}H(He,pt)H, at beam energy of 17 MeV. Once selection of protons and tritons detected in coincidence and the selection of quasi-free events, the obtained S-factor is compared with direct measurements. Such data are in agreement with the direct ones and a pole invariance test has been obtained comparing the present results with another {sup 2}H(d,p){sup 3}H THM measurements, where a different spectator particle was employed.

  18. Ecocatalysis for 2H-chromenes synthesis: an integrated approach for phytomanagement of polluted ecosystems.

    PubMed

    Escande, Vincent; Velati, Alicia; Grison, Claude

    2015-04-01

    A direct, general and efficient method to synthesize 2H-chromenes (2H-benzo[b]pyrans), identified as environmentally friendly pesticides, has been developed. This approach lays on the new concept of ecocatalysis, which involves the use of biomass from phytoextraction processes, as a valuable source of metallic elements for chemical synthesis. This methodology is similar or superior to known methods, affording 2H-chromenes with good to excellent yields (60-98%), including the preparation of precocene I, a natural insect growth regulator, with 91% yield. The approach is ideal for poor reactive substrates such as phenol or naphthol, classically transformed into 2H-chromenes by methodologies associated with environmental issues. These results illustrate the interest of combining phytoextraction and green synthesis of natural insecticides. PMID:25131683

  19. Oxydifluoromethylation of Alkenes by Photoredox Catalysis: Simple Synthesis of CF2H-Containing Alcohols.

    PubMed

    Arai, Yusuke; Tomita, Ren; Ando, Gaku; Koike, Takashi; Akita, Munetaka

    2016-01-22

    We have developed a novel and simple protocol for the direct incorporation of a difluoromethyl (CF2 H) group into alkenes by visible-light-driven photoredox catalysis. The use of fac-[Ir(ppy)3] (ppy=2-pyridylphenyl) photocatalyst and shelf-stable Hu's reagent, N-tosyl-S-difluoromethyl-S-phenylsulfoximine, as a CF2 H source is the key to success. The well-designed photoredox system achieves synthesis of not only β-CF2 H-substituted alcohols but also ethers and an ester from alkenes through solvolytic processes. The present method allows a single-step and regioselective formation of C(sp(3))-CF2 H and C(sp(3))-O bonds from C=C moiety in alkenes, such as hydroxydifluoromethylation, regardless of terminal or internal alkenes. Moreover, this methodology tolerates a variety of functional groups. PMID:26639021

  20. Alcohol binding to liposomes by 2H NMR and radiolabel binding assays: does partitioning describe binding?

    PubMed Central

    Dubey, A K; Eryomin, V A; Taraschi, T F; Janes, N

    1996-01-01

    Implicit within the concept of membrane-buffer partition coefficients of solutes is a nonspecific solvation mechanism of solute binding. However, (2)H NMR studies of the binding of (2)H(6)-ethanol and [1-(2)H(2)] n-hexanol to phosphatidylcholine vesicles have been interpreted as evidence for two distinct alcohol binding modes. One binding mode was reported to be at the membrane surface. The second mode was reported to be within the bilayer interior. An examination of the (2)H NMR binding studies, together with direct radiolabel binding assays, shows that other interpretations of the data are more plausible. The results are entirely consistent with partitioning (nonspecific binding) as the sole mode of alcohol binding to liposomes, in accord with our previous thermodynamic interpretation of alcohol action in phosphatidylcholine liposomes. PMID:9172754