WorldWideScience

Sample records for diamagnetic cavity relevant

  1. The interaction of a flowing plasma with a dipole magnetic field: measurements and modelling of a diamagnetic cavity relevant to spacecraft protection

    International Nuclear Information System (INIS)

    Bamford, R; Bradford, J; Bingham, R; Gargate, L; Hapgood, M; Stamper, R; Gibson, K J; Thornton, A J; Silva, L O; Fonseca, R A; Norberg, C; Todd, T

    2008-01-01

    Here we describe a new experiment to test the shielding concept of a dipole-like magnetic field and plasma, surrounding a spacecraft forming a 'mini magnetosphere'. Initial laboratory experiments have been conducted to determine the effectiveness of a magnetized plasma barrier to be able to expel an impacting, low beta, supersonic flowing energetic plasma representing the solar wind. Optical and Langmuir probe data of the plasma density, the plasma flow velocity and the intensity of the dipole field clearly show the creation of a narrow transport barrier region and diamagnetic cavity virtually devoid of energetic plasma particles. This demonstrates the potential viability of being able to create a small 'hole' in a solar wind plasma, of the order of the ion Larmor orbit width, in which an inhabited spacecraft could reside in relative safety. The experimental results have been quantitatively compared with a 3D particle-in-cell 'hybrid' code simulation that uses kinetic ions and fluid electrons, showing good qualitative agreement and excellent quantitative agreement. Together the results demonstrate the pivotal role of particle kinetics in determining generic plasma transport barriers.

  2. Axisymmetric particle-in-cell simulations of diamagnetic-cavity formation in vacuum

    International Nuclear Information System (INIS)

    Gisler, G.

    1989-01-01

    Axisymmetric simulations of the expansion of a hot plasma suddenly introduced into a vacuum containing a weak magnetic field were performed using an electromagnetic particle-in-cell code. Both uniform and gradient fields have been used, with the simulation axis along the principle field direction. The formation of a diamagnetic cavity requires an initial plasma β > 1; as the expansion proceeds, β diminishes, and the field eventually recovers. The maximum spatial extent of the cavity and its duration can be obtained from simple dynamical considerations. Field-aligned ion acceleration behind the electron front is observed in all field geometries and strengths. In the case of expansion into a divergent field, the plasma is found to move down the field gradient by ambipolar diffusion. These simulations are relevant to active release experiments in the Earth's magnetosphere, to pellet ablation experiments, and to the naturally occurring diamagnetic bubbles observed at the Earth's foreshock

  3. Dynamic unmagnetized plasma in the diamagnetic cavity around comet 67P/Churyumov-Gerasimenko

    Science.gov (United States)

    Hajra, Rajkumar; Henri, Pierre; Vallières, Xavier; Moré, Jerome; Gilet, Nicolas; Wattieaux, Gaetan; Goetz, Charlotte; Richter, Ingo; Tsurutani, Bruce T.; Gunell, Herbert; Nilsson, Hans; Eriksson, Anders I.; Nemeth, Zoltan; Burch, James L.; Rubin, Martin

    2018-04-01

    The Rosetta orbiter witnessed several hundred diamagnetic cavity crossings (unmagnetized regions) around comet 67P/Churyumov-Gerasimenko during its two year survey of the comet. The characteristics of the plasma environment inside these diamagnetic regions are studied using in situ measurements by the Rosetta Plasma Consortium instruments. Although the unmagnetized plasma density has been observed to exhibit little dynamics compared to the very dynamical magnetized cometary plasma, we detected several localized dynamic plasma structures inside those diamagnetic regions. These plasma structures are not related to the direct ionization of local cometary neutrals. The structures are found to be steepened, asymmetric plasma enhancements with typical rising-to-descending slope ratio of ˜2.8 (±1.9), skewness ˜0.43 (±0.36), mean duration of ˜2.7 (±0.9) min and relative density variation ΔN/N of ˜0.5 (±0.2), observed close to the electron exobase. Similar steepened plasma density enhancements were detected at the magnetized boundaries of the diamagnetic cavity as well as outside the diamagnetic region. The plausible scalelength and propagation direction of the structures are estimated from simple plasma dynamics considerations. It is suggested that they are large-scale unmagnetized plasma enhancements, transmitted from the very dynamical outer magnetized region to the inner magnetic field-free cavity region.

  4. Three-dimensional simulation of diamagnetic cavity formation by a finite-sized plasma beam

    International Nuclear Information System (INIS)

    Thomas, V.A.

    1989-01-01

    The problem of collisionless coupling between a plasma beam and a background plasma is examined using a three-dimensional hybrid code. The beam is assumed to be moving parallel to an ambient magnetic field at a speed greater than the local Alfven speed. In addition, the beam has a finite spatial extent in the directions perpendicular to the magnetic field and is uniform and infinite in the direction parallel to the ambient magnetic field. Such a system is susceptible to coupling of the beam ions with the background ions via an electromagnetic ion beam instability. This instability isotropizes the beam and energizes the background plasma. A large-amplitude Alfven wave traveling radially away from the interaction region is associated with the energized background plasma. The process described here is one which may be responsible for the formation of diamagnetic cavities observed in the solar wind. copyright American Geophysical Union 1989

  5. Outbursts and diamagnetic cavities in comet 67P/Churyumov-Gerasimenko

    Science.gov (United States)

    Voelzke, M. R.

    2018-03-01

    On 2014 August 06 the Rosetta spacecraft arrived at comet 67P/Churyumov-Gerasimenko. Since then, the spacecraft accompanied the comet on its journey around the Sun (Glassmeier et al. 2007), until the end of the mission on 2016 September 30. This work tries to understand the possible connections between the 665 reported diamagnetic regions (Goetz et al. 2016), detected from April 2015 to February 2016 around the comet 67P/Churyumov-Gerasimenko, with the fluxgate magnetometer of the Rosetta Plasma Consortium (RPC-MAG), when the heliocentric distance of the comet from the sun varied from 1.8 to 2.4 AU and the 34 reported outbursts (Vincent et al. 2016), detected from July to September 2015, with the Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) cameras, when the ESA's Rosetta spacecraft changed the cometocentric distance from 155 to 817 km.

  6. 3-D mesoscale MHD simulations of magnetospheric cusp-like configurations: cusp diamagnetic cavities and boundary structure

    Directory of Open Access Journals (Sweden)

    E. Adamson

    2012-02-01

    Full Text Available We present results from mesoscale simulations of the magnetospheric cusp region for both strongly northward and strongly southward interplanetary magnetic field (IMF. Simulation results indicate an extended region of depressed magnetic field and strongly enhanced plasma β which exhibits a strong dependence on IMF orientation. These structures correspond to the Cusp Diamagnetic Cavities (CDC's. The typical features of these CDC's are generally well reproduced by the simulation. The inner boundaries between the CDC and the magnetosphere are gradual transitions which form a clear funnel shape, regardless of IMF orientation. The outer CDC/magnetosheath boundary exhibits a clear indentation in both the x-z and y-z planes for southward IMF, while it is only indented in the x-z plane for northward, with a convex geometry in the y-z plane. The outer boundary represents an Alfvénic transition, mostly consistent with a slow-shock, indicating that reconnection plays an important role in structuring the high-altitude cusp region.

  7. Short Note Ground cavity nest temperatures and their relevance to ...

    African Journals Online (AJOL)

    Blue Swallows Hirundo atrocaerulea are Critically Endangered within South Africa. They nest in natural underground holes in mist-belt grasslands. Temperature dataloggers were used to record ground cavity nest (Tn) and ambient temperature (Ta) for one artificial and 11 natural Blue Swallow nests. Mean ground cavity Tn ...

  8. Peierls' Elucidation of Diamagnetism

    Indian Academy of Sciences (India)

    IAS Admin

    portion of the boundary electrons has however a large contribution to M because of the largeness of the magnitude of the position vector r. Bohr–van Leeuwen theorem which states that. Diamagnetism does not exist in Classical. Mechanics. It is through A that the magnetic field B enters into the discussion via the relation:.

  9. Faraday diamagnetism under slowly oscillating magnetic fields

    Science.gov (United States)

    Kimura, Tsunehisa; Kimura, Fumiko; Kimura, Yosuke

    2018-04-01

    Diamagnetism is a universal phenomenon of materials arising from the orbital motion of electrons bound to atoms, which is commonly known as Langevin diamagnetism. The orbital motion also occurs according to the Faraday's law of induction when the applied magnetic field is oscillating. However, the influence of this dynamic effect on the magnetism of materials has seldom been studied. Here, we propose a new type diamagnetism coined Faraday diamagnetism. The magnitude of this diamagnetism evaluated by an atomic electric circuit model was as large as that of Langevin diamagnetism. The predicted scale of Faraday diamagnetism was supported by experiments.

  10. Diamagnetic response in zigzag hexagonal silicene rings

    International Nuclear Information System (INIS)

    Xu, Ning; Chen, Qiao; Tian, Hongyu; Ding, Jianwen; Liu, Junfeng

    2016-01-01

    Highlights: • Hexagonal silicene rings possess unusually large diamagnetic moments. • The magnetic-field-driven spin-up electrons flow anticlockwise and spin-down electrons flow clockwise along the rings. • The large diamagnetic moment is the result of competition of spin-up and spin-down electrons. - Abstract: Hexagonal silicene rings with unusually large diamagnetic moments have been found in a theoretical study of the electronic and magnetic properties. In the presence of effective spin–orbit coupling, the magnetic-field-driven spin-up electrons flow anticlockwise exhibiting colossal diamagnetic moments, while the spin-down electrons flow clockwise exhibiting colossal paramagnetic moments along the rings. The large diamagnetic moment is thus the result of competition of spin-up and spin-down electrons, which can be modulated by spin–orbit coupling strength and exchange field.

  11. Diamagnetic response in zigzag hexagonal silicene rings

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Ning, E-mail: nxu@ycit.cn [Department of Physics, Yancheng Institute of Technology, Yancheng 224051 (China); Chen, Qiao [Department of Physics, Hunan Institute of Engineering, Xiangtan 411104 (China); Tian, Hongyu [Department of Physics, Yancheng Institute of Technology, Yancheng 224051 (China); Ding, Jianwen [Department of Physics, Xiangtan University, Xiangtan 411105 (China); Liu, Junfeng, E-mail: liu.jf@sustc.edu.cn [Department of Physics, South University of Science and Technology of China, Shenzhen 518055 (China)

    2016-09-16

    Highlights: • Hexagonal silicene rings possess unusually large diamagnetic moments. • The magnetic-field-driven spin-up electrons flow anticlockwise and spin-down electrons flow clockwise along the rings. • The large diamagnetic moment is the result of competition of spin-up and spin-down electrons. - Abstract: Hexagonal silicene rings with unusually large diamagnetic moments have been found in a theoretical study of the electronic and magnetic properties. In the presence of effective spin–orbit coupling, the magnetic-field-driven spin-up electrons flow anticlockwise exhibiting colossal diamagnetic moments, while the spin-down electrons flow clockwise exhibiting colossal paramagnetic moments along the rings. The large diamagnetic moment is thus the result of competition of spin-up and spin-down electrons, which can be modulated by spin–orbit coupling strength and exchange field.

  12. Fluctuation diamagnetism in two-band superconductors

    Science.gov (United States)

    Adachi, Kyosuke; Ikeda, Ryusuke

    2016-04-01

    Anomalously large fluctuation diamagnetism around the superconducting critical temperature has been recently observed in iron selenide (FeSe) [Kasahara et al. (unpublished)]. This indicates that superconducting fluctuations (SCFs) play a more significant role in FeSe, which supposedly has a two-band structure, than in the familiar single-band superconductors. Motivated by the data on FeSe, SCF-induced diamagnetism is examined in a two-band system, on the basis of a phenomenological approach with a Ginzburg-Landau functional. The obtained results indicate that the SCF-induced diamagnetism may be more enhanced than that in a single-band system due to the existence of two distinct fluctuation modes. Such enhancement of diamagnetism unique to a two-band system seems consistent with the large diamagnetism observed in FeSe, though still far from a quantitative agreement.

  13. Relaxation properties in classical diamagnetism

    Science.gov (United States)

    Carati, A.; Benfenati, F.; Galgani, L.

    2011-06-01

    It is an old result of Bohr that, according to classical statistical mechanics, at equilibrium a system of electrons in a static magnetic field presents no magnetization. Thus a magnetization can occur only in an out of equilibrium state, such as that produced through the Foucault currents when a magnetic field is switched on. It was suggested by Bohr that, after the establishment of such a nonequilibrium state, the system of electrons would quickly relax back to equilibrium. In the present paper, we study numerically the relaxation to equilibrium in a modified Bohr model, which is mathematically equivalent to a billiard with obstacles, immersed in a magnetic field that is adiabatically switched on. We show that it is not guaranteed that equilibrium is attained within the typical time scales of microscopic dynamics. Depending on the values of the parameters, one has a relaxation either to equilibrium or to a diamagnetic (presumably metastable) state. The analogy with the relaxation properties in the Fermi Pasta Ulam problem is also pointed out.

  14. Compensation of Environmental Natural Underground Cavities in Environmental Licensing: The Hollow of Fixing the Possibility of Testimony for Impacts of Irreversible Developments in Underground Cavities Degree of Relevance Average

    Directory of Open Access Journals (Sweden)

    Dioclides José Maria

    2016-06-01

    Full Text Available This study aims to analyze the Decree. 99.556 of 10.1º.1990 with the wording given by Decree. 6640, of 11.07.2008 dealing on protection of speleological heritage. The hypothesis is application of compensatory measure of permanent preservation cavities testimony in irreversible impacts of projects of medium significance level of underground cavities. By qualitative method and bibliographic research, it presented considerations about the possibility of preserving permanently underground cavities testimony by project impacts on medium relevance degree of natural underground cavities.

  15. Diamagnetic flux measurement in Aditya tokamak

    International Nuclear Information System (INIS)

    Kumar, Sameer; Jha, Ratneshwar; Lal, Praveen; Hansaliya, Chandresh; Gopalkrishna, M. V.; Kulkarni, Sanjay; Mishra, Kishore

    2010-01-01

    Measurements of diamagnetic flux in Aditya tokamak for different discharge conditions are reported for the first time. The measured diamagnetic flux in a typical discharge is less than 0.6 mWb and therefore it has required careful compensation for various kinds of pick-ups. The hardware and software compensations employed in this measurement are described. We introduce compensation of a pick-up due to plasma current of less than 20 kA in short duration discharges, in which plasma pressure gradient is supposed to be negligible. The flux measurement during radio frequency heating is also presented in order to validate compensation.

  16. Research support for plasma diagnostics on Elmo Bumpy Torus: investigation of diamagnetic diagnostics for the electron rings

    International Nuclear Information System (INIS)

    Carpenter, K.H.

    1981-02-01

    Diamagnetic diagnostics for the EBT electron rings are fundamental to the experiment. The diamagnetic flux pickup loops on each cavity output signals proportional to ring perpendicular energy. A data analysis technique is described, which in its simplest form is subtracting 1/4 the signal from each neighboring cavity pickup loop from the central one's, which provides a signal proportional to the energy in a single ring. The calibration factor relating absolute perpendicular energy to diamagnetic signal depends weakly on the geometrical model for the ring. Calculations with a bumpy cylinder MHD equilibrium code give calibration factors in reasonable agreement (20%) to the values obtained using a simple, concentric cylindrical current sheet model. The cylindrical current sheet model is used to show that diamagnetic field components measured external to the plasma require high precision or correlation with other diagnostics in order to fix model parameters. A computer simulation shows an assumption of constant ring thickness and energy density with increasing length (and energy) is compatible to diamagnetic field observations on NBT

  17. Spin noise measurement with diamagnetic atoms

    International Nuclear Information System (INIS)

    Takeuchi, M.; Ichihara, S.; Takano, T.; Kumakura, M.; Takahashi, Y.

    2007-01-01

    We report the measurement of the atomic spin noise of the diamagnetic atom ytterbium (Yb). Yb has various merits for utilizing the quantum nature of the atomic spin ensemble compared with the paramagnetic atoms used in all previous experiments. From the magnitude of the noise level and dependence on the detuning, we concluded that we succeeded in the measurement of 171 Yb atomic spin noise in an atomic beam

  18. Toroidal Simulations of Sawteeth with Diamagnetic Effects

    Science.gov (United States)

    Beidler, Matthew; Cassak, Paul; Jardin, Stephen

    2014-10-01

    The sawtooth crash in tokamaks limits the core temperature, adversely impacts confinement, and seeds disruptions. Adequate knowledge of the physics governing the sawtooth crash and a predictive capability of its ramifications has been elusive, including an understanding of incomplete reconnection, i.e., why sawteeth often cease prematurely before processing all available magnetic flux. There is an indication that diamagnetic suppression could play an important role in this phenomenon. While computational tools to study toroidal plasmas have existed for some time, extended-MHD physics have only recently been integrated. Interestingly, incomplete reconnection has been observed in simulations when diamagnetic effects are present. In the current study, we employ the three-dimensional, extended-MHD code M3D-C1 to study the sawtooth crash in a toroidal geometry. In particular, we describe how magnetic reconnection at the q = 1 rational surface evolves when self-consistently increasing diamagnetic effects are present. We also explore how the termination of reconnection may lead to core-relaxing ideal-MHD instabilities.

  19. Diamagnetic expansions for perfect quantum gases

    DEFF Research Database (Denmark)

    Briet, Philippe; Cornean, Horia; Louis, Delphine

    2006-01-01

    In this work we study the diamagnetic properties of a perfect quantum gas in the presence of a constant magnetic field of intensity B. We investigate the Gibbs semigroup associated with the one particle operator at finite volume, and study its Taylor series with respect to the field parameter ome......:=eB/c in different topologies. This allows us to prove the existence of the thermodynamic limit for the pressure and for all its derivatives with respect to omega (the so-called generalized susceptibilities)....

  20. Magnetic Reconnection Processes Involving Modes Propagating in the Ion Diamagnetic Velocity Direction

    Science.gov (United States)

    Buratti, P.; Coppi, B.; Pucella, G.; Zhou, T.

    2013-10-01

    Experiments in weakly collisional plasma regimes, (e.g. neutral beam heated plasmas in the H-regime), measuring the Doppler shift associated with the plasma local rotation, have shown that the toroidal mode phase velocity vph in the frame with Er = 0 is in the direction of the ion diamagnetic velocity. For ohmically heated plasmas, with higher collisionalities, vph in the laboratory frame is in the direction of the electron diamagnetic velocity, but plasma rotation is reversed as well, and vph, in the Er = 0 frame, is in the ion diamagnetic velocity direction. Theoretically, two classes of reconnecting modes should emerge: drift-tearing modes and ``inductive modes'' that depend on the effects of a finite plasma inductivity. The former modes, with vph in the direction of the electron diamagnetic velocity, require the pre-excitation of a different kind of mode in order to become unstable in weakly collisional regimes. The second kind of modes has a growth rate associated with the relevant finite ion viscosity. A comprehensive theory is presented. Sponsored in part by the US DOE.

  1. Design of diamagnetic loop on EAST superconducting tokamak

    International Nuclear Information System (INIS)

    Xi Weibin; Shen Biao; Qian Jinping; Wu Songtao; Wan Baonan

    2007-01-01

    The design of EAST diamagnetic measurement system including diamagnetic loop and compensation loop has been given. The advantage of this method is that, the compensation loop is applied for eliminating the change of toroidal flux produced by the toroidal coils and the adjustable structure can be used to decrease the error signals come from the poloidal field. On the other hand, the effect of the material and structure on the diamagnetic loop is detailedly checked during engineering design. Error analysis of the measurement system is given. (authors)

  2. Superconductivity, diamagnetism, and the mean inner potential of solids

    Energy Technology Data Exchange (ETDEWEB)

    Hirsch, J.E. [Department of Physics, University of California San Diego, La Jolla, CA (United States)

    2014-01-15

    The mean inner potential of a solid is known to be proportional to its diamagnetic susceptibility. Superconductors exhibit giant diamagnetism. What does this say about the connection between superconductivity and mean inner potential? Nothing, according to the conventional theory of superconductivity. Instead, it is proposed that a deep connection exists between the mean inner potential, diamagnetism, and superconductivity: that they are all intimately linked to the fundamental charge asymmetry of matter. It is discussed how this physics can be probed experimentally and what the implications of different experimental findings would be for the understanding of superconductivity. (copyright 2013 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Diamagnetic susceptibility of a confined donor in inhomogeneous quantum dots

    International Nuclear Information System (INIS)

    Rahmani, K; Zorkani, I; Jorio, A

    2011-01-01

    The binding energy and diamagnetic susceptibility χ dia are estimated for a shallow donor confined to move in GaAs-GaAlAs inhomogeneous quantum dots. The calculation was performed within the effective mass approximation and using the variational method. The results show that the binding energy and the diamagnetic susceptibility χ dia depend strongly on the core radius and the shell radius. We have demonstrated that there is a critical value of the ratio of the inner radius to the outer radius which may be important for nanofabrication techniques. The binding energy E b shows a minimum for a critical value of this ratio depending on the value of the outer radius and shows a maximum when the donor is placed at the center of the spherical layer. The diamagnetic susceptibility is more sensitive to variations of the radius for a large spherical layer. The binding energy and diamagnetic susceptibility depend strongly on the donor position.

  4. How to Simply Demonstrate Diamagnetic Levitation with Pencil Lead

    Science.gov (United States)

    Koudelkova, Vera

    2016-01-01

    A new simple arrangement how to demonstrate diamagnetic levitation is presented. It uses pencil lead levitating in a track built from neodymium magnets. This arrangement can also be used as a classroom experiment.

  5. Real-time diamagnetic flux measurements on ASDEX Upgrade.

    Science.gov (United States)

    Giannone, L; Geiger, B; Bilato, R; Maraschek, M; Odstrčil, T; Fischer, R; Fuchs, J C; McCarthy, P J; Mertens, V; Schuhbeck, K H

    2016-05-01

    Real-time diamagnetic flux measurements are now available on ASDEX Upgrade. In contrast to the majority of diamagnetic flux measurements on other tokamaks, no analog summation of signals is necessary for measuring the change in toroidal flux or for removing contributions arising from unwanted coupling to the plasma and poloidal field coil currents. To achieve the highest possible sensitivity, the diamagnetic measurement and compensation coil integrators are triggered shortly before plasma initiation when the toroidal field coil current is close to its maximum. In this way, the integration time can be chosen to measure only the small changes in flux due to the presence of plasma. Two identical plasma discharges with positive and negative magnetic field have shown that the alignment error with respect to the plasma current is negligible. The measured diamagnetic flux is compared to that predicted by TRANSP simulations. The poloidal beta inferred from the diamagnetic flux measurement is compared to the values calculated from magnetic equilibrium reconstruction codes. The diamagnetic flux measurement and TRANSP simulation can be used together to estimate the coupled power in discharges with dominant ion cyclotron resonance heating.

  6. Bifurcated equilibria in two-dimensional MHD with diamagnetic effects

    International Nuclear Information System (INIS)

    Ottaviani, M.; Tebaldi, C.

    1998-12-01

    In this work we analyzed the sequence of bifurcated equilibria in two-dimensional reduced magnetohydrodynamics. Diamagnetic effects are studied under the assumption of a constant equilibrium pressure gradient, not altered by the formation of the magnetic island. The formation of an island when the symmetric equilibrium becomes unstable is studied as a function of the tearing mode stability parameter Δ' and of the diamagnetic frequency, by employing fixed-points numerical techniques and an initial value code. At larger values of Δ' a tangent bifurcation takes place, above which no small island solutions exist. This bifurcation persists up to fairly large values of the diamagnetic frequency (of the order of one tenth of the Alfven frequency). The implications of this phenomenology for the intermittent MHD dynamics observed in tokamaks is discussed. (authors)

  7. Review - On-chip diamagnetic repulsion in continuous flow

    Directory of Open Access Journals (Sweden)

    Mark D Tarn, Noriyuki Hirota, Alexander Iles and Nicole Pamme

    2009-01-01

    Full Text Available We explore the potential of a microfluidic continuous flow particle separation system based on the repulsion of diamagnetic materials from a high magnetic field. Diamagnetic polystyrene particles in paramagnetic manganese (II chloride solution were pumped into a microfluidic chamber and their deflection behaviour in a high magnetic field applied by a superconducting magnet was investigated. Two particle sizes (5 and 10 μm were examined in two concentrations of MnCl2 (6 and 10%. The larger particles were repelled to a greater extent than the smaller ones, and the effect was greatly enhanced when the particles were suspended in a higher concentration of MnCl2. These findings indicate that the system could be viable for the separation of materials of differing size and/or diamagnetic susceptibility, and as such could be suitable for the separation and sorting of small biological species for subsequent studies.

  8. Development of an ex vivo retention model simulating bioadhesion in the oral cavity using human saliva and physiologically relevant irrigation media

    DEFF Research Database (Denmark)

    Madsen, Katrine D.; Sander, Camilla; Baldursdottir, Stefania

    2013-01-01

    In recent years, there has been a particular interest in bioadhesive formulations for oromucosal drug delivery as this may promote prolonged local therapy and enhanced systemic effect. Saliva plays a vital role in oromucosal drug absorption by dissolving the drug and presenting it to the mucosal...... in the oral cavity. Thus we aimed at developing an advanced ex vivo buccal retention model, with focus on choosing a physiologically relevant irrigation media closely resembling human saliva. Spray dried chitosan microparticles containing metformin hydrochloride as an example of a small hydrophilic drug, were...... employed as bioadhesive formulations. Chewing-stimulated human whole saliva was collected and characterized for use in retention studies in comparison with four artificial irrigation media; phosphate buffer, Saliva Orthana(®), porcine gastric mucin base media (PGM3), and xanthan gum based media (XG2...

  9. Continuous-flow sheathless diamagnetic particle separation in ferrofluids

    International Nuclear Information System (INIS)

    Zhou, Yilong; Song, Le; Yu, Liandong; Xuan, Xiangchun

    2016-01-01

    Separating particles from a complex mixture is often necessary in many chemical and biomedical applications. This work presents a continuous-flow sheathless diamagnetic particle separation in ferrofluids through U-shaped microchannels. Due to the action of a size-dependent magnetic force, diamagnetic particles are focused into a single stream in the inlet branch of the U-turn and then continuously separated into two streams in its outlet branch. A 3D numerical model is developed to predict and understand the diamagnetic particle transport during this separation process. The numerical predictions are found to agree well with the experimental observations in a systematic study of the effects of multiple parameters including ferrofluid flow rate, concentration and magnet-channel distance. Additional numerical studies of the geometric effects of the U-turn reveal that increasing the outlet-branch width of the U-turn can significantly enhance the diamagnetic particle separation in ferrofluids. - Highlights: • Particles are focused and separated in the two branches of a U-shaped microchannel. • Negative magnetophoretic motion in ferrofluids causes the particle deflection. • A 3D numerical model is developed to simulate the particle separation. • Multiple parametric effects are studied both experimentally and numerically. • Increasing the outlet-branch width significantly enhances the particle separation.

  10. Continuous-flow sheathless diamagnetic particle separation in ferrofluids

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Yilong [Department of Mechanical Engineering, Clemson University, Clemson, SC 29634-0921 (United States); Song, Le [School of Instrument Science and Opto-electronic Engineering, Hefei University of Technology, Hefei 230009 (China); Yu, Liandong, E-mail: liandongyu@hfut.edu.cn [School of Instrument Science and Opto-electronic Engineering, Hefei University of Technology, Hefei 230009 (China); Xuan, Xiangchun, E-mail: xcxuan@clemson.edu [Department of Mechanical Engineering, Clemson University, Clemson, SC 29634-0921 (United States)

    2016-08-15

    Separating particles from a complex mixture is often necessary in many chemical and biomedical applications. This work presents a continuous-flow sheathless diamagnetic particle separation in ferrofluids through U-shaped microchannels. Due to the action of a size-dependent magnetic force, diamagnetic particles are focused into a single stream in the inlet branch of the U-turn and then continuously separated into two streams in its outlet branch. A 3D numerical model is developed to predict and understand the diamagnetic particle transport during this separation process. The numerical predictions are found to agree well with the experimental observations in a systematic study of the effects of multiple parameters including ferrofluid flow rate, concentration and magnet-channel distance. Additional numerical studies of the geometric effects of the U-turn reveal that increasing the outlet-branch width of the U-turn can significantly enhance the diamagnetic particle separation in ferrofluids. - Highlights: • Particles are focused and separated in the two branches of a U-shaped microchannel. • Negative magnetophoretic motion in ferrofluids causes the particle deflection. • A 3D numerical model is developed to simulate the particle separation. • Multiple parametric effects are studied both experimentally and numerically. • Increasing the outlet-branch width significantly enhances the particle separation.

  11. Bifurcations and complete chaos for the diamagnetic Kepler problem

    Science.gov (United States)

    Hansen, Kai T.

    1995-03-01

    We describe the structure of bifurcations in the unbounded classical diamagnetic Kepler problem. We conjecture that this system does not have any stable orbits and that the nonwandering set is described by a complete trinary symbolic dynamics for scaled energies larger than ɛc=0.328 782. . ..

  12. Bifurcations and Complete Chaos for the Diamagnetic Kepler Problem

    OpenAIRE

    Hansen, Kai T.

    1995-01-01

    We describe the structure of bifurcations in the unbounded classical Diamagnetic Kepler problem. We conjecture that this system does not have any stable orbits and that the non-wandering set is described by a complete trinary symbolic dynamics for scaled energies larger then $\\epsilon_c=0.328782\\ldots$.

  13. Diamagnetism in spinel compound CuIr2S4

    International Nuclear Information System (INIS)

    Yagasaki, K.; Nakama, T.

    2007-01-01

    The diamagnetic susceptibility in CuIr 2 S 4 is independent of temperature up to just below metal-insulator transition temperature. If activation of electrons to higher levels occurs with breaking dimer pairs, the residual electrons at the dimer position and the activated electrons to the anti-bonding orbital make localized free spins giving a Langevin paramagnetism. Assuming no magnetic interaction between the localized free spins, the susceptibility is calculated using the energy gap obtained from the conductivity assumed to be a conventional semiconductor. The calculated results cannot explain the temperature-independent diamagnetism. The real energy gap is too large for thermal electron activation, however, conduction is induced thermally over several orders of magnitude within insulating phase. From the above results, we claimed new conduction mechanism named traveling dimer conduction: dimer shifts its position by electron hopping to neighbor position without electron activation over the energy gap

  14. Diamagnetic Raman Optical Activity of Chlorine, Bromine, and Iodine Gases

    Czech Academy of Sciences Publication Activity Database

    Šebestík, Jaroslav; Kapitán, J.; Pačes, Ondřej; Bouř, Petr

    2016-01-01

    Roč. 55, č. 10 (2016), s. 3504-3508 ISSN 1433-7851 R&D Projects: GA ČR GA13-03978S; GA ČR(CZ) GA14-00431S; GA ČR(CZ) GA16-05935S Institutional support: RVO:61388963 Keywords : angular momentum theory * diamagnetic molecules * excited electronic states * magnetic field * Raman optical activity Subject RIV: CC - Organic Chemistry Impact factor: 11.994, year: 2016

  15. The effect of collisionality and diamagnetism on the plasma dynamo

    International Nuclear Information System (INIS)

    Ji, H.; Yagi, Y.; Hattori, K.; Hirano, Y.; Shimada, T.; Maejima, Y.; Hayase, K.; Almagri, A.F.; Prager, S.C.; Sarff, J.S.

    1995-01-01

    Fluctuation-induced dynamo forces are measured over a wide range of electron collisionality in the edge of TPE-1RM20 Reversed-Field Pinch (RFP). In the collisionless region the Magnetohydrodynamic (MHD) dynamo alone can sustain the parallel current, while in the collisional region a new dynamo mechanism resulting from the fluctuations in the electron diamagnetic drift becomes dominant. A comprehensive picture of the RFP dynamo emerges by combining with earlier results from MST and REPUTE RFPs

  16. Stabilization of kinetic internal kink mode by ion diamagnetic effects

    International Nuclear Information System (INIS)

    Naitou, H.; Kuramoto, T.; Kobayashi, T.; Yagi, M.; Tokuda, S.; Matsumoto, T.

    2000-04-01

    Ion diamagnetic effects on the m=1 (poloidal mode number) and n=1 (toroidal mode number) kinetic internal kink mode are studied numerically by the three-field gyro-reduced-MHD code in the cylindrical coordinates, GRM3F-CY. In the derivation of the gryo-reduced-MHD model including the ion diamagnetic effects, finite gyroradius effects of ions are added to the gyrokinetic Poisson equation (quasi-neutral condition) and the convection term of the conservation law of the ion density. It is found that the long wavelength approximation, ksub(perpendicular) ρ ti ti is the thermal ion gyroradius, fails to reproduce the correct dispersion relation; the formulation valid even for ksub(perpendicular) ρ ti >> 1 is necessary. The results of numerical calculation coincide with the theory for |ω *e |+|ω *i | 0 , where the growth rate reduces as the density gradient increases. Here ω *e and ω *i are electron and ion diamagnetic angular frequencies estimated at the rational surface of q=1 (q is a safety factor), respectively, and γ 0 is the growth rate for the uniform density. Very weak instability, however, is observed for |ω *e |+|ω *i | 0 , where the theory predicts the complete stabilization. This residual instability appears since the region with the density gradient is limited in the radial direction and the stabilization by the outgoing drift-wave like mode becomes incomplete. (author)

  17. Development of an ex vivo retention model simulating bioadhesion in the oral cavity using human saliva and physiologically relevant irrigation media.

    Science.gov (United States)

    Madsen, Katrine D; Sander, Camilla; Baldursdottir, Stefania; Pedersen, Anne Marie L; Jacobsen, Jette

    2013-05-20

    In recent years, there has been a particular interest in bioadhesive formulations for oromucosal drug delivery as this may promote prolonged local therapy and enhanced systemic effect. Saliva plays a vital role in oromucosal drug absorption by dissolving the drug and presenting it to the mucosal surface. However, the rheological, chemical, and interfacial properties of this complex biological fluid may strongly affect the adhesion of bioadhesive formulations. There is a need for well characterized in vitro models to assess the bioadhesive properties of oral dosage forms for administration in the oral cavity. Thus we aimed at developing an advanced ex vivo buccal retention model, with focus on choosing a physiologically relevant irrigation media closely resembling human saliva. Spray dried chitosan microparticles containing metformin hydrochloride as an example of a small hydrophilic drug, were employed as bioadhesive formulations. Chewing-stimulated human whole saliva was collected and characterized for use in retention studies in comparison with four artificial irrigation media; phosphate buffer, Saliva Orthana(®), porcine gastric mucin base media (PGM3), and xanthan gum based media (XG2). Retention of metformin, applied as spray dried microparticles on porcine buccal mucosa, greatly depended on the characteristics of the irrigation media. When rheology of the irrigation media was examined, changes in retention profiles could be interpreted, as irrigation media containing mucin and xanthan gum possessed a higher viscosity than phosphate buffer, which led to longer retention of the drug due to better hydration of the mucosa and the spray dried microparticles. Metformin retention profiles were comparable when human saliva, Saliva Orthana(®), or PGM3 were used as irrigation media. Moreover, PGM3 displayed physico-chemical properties closest to those of human saliva with regard to pH, protein content and surface tension. Saliva Orthana(®) and PGM3 are therefore

  18. Theory of diamagnetic signal in current-free stellarators

    International Nuclear Information System (INIS)

    Pustovitov, Vladimir D.

    2010-01-01

    The toroidal magnetic flux through the plasma column is calculated analytically for current-free stellarators of arbitrary geometry without assumptions on the plasma shape, aspect ratio, etc. This is done with accuracy sufficient for extracting the contribution due to the finite plasma pressure from this flux. The final result is a formula relating the measured diamagnetic signal with β, the ratio of the plasma pressure to the magnetic pressure. This formula is obtained assuming small β and the relative depth of the magnetic well. These are natural conditions for stellarators, therefore the final result can be recommended for magnetic diagnostics without practical limitations. (author)

  19. Diamagnetic measurements on ISX-B: method and results

    International Nuclear Information System (INIS)

    Neilson, G.H.

    1983-10-01

    A diamagnetic loop is used on the ISX-B tokamak to measure the change in toroidal magnetic flux, sigma phi, caused by finite plasma current and perpendicular pressure. From this measurement, the perpendicular poloidal beta β/sub I perpendicular to/ is determined. The principal difficulty encountered is in identifying and making corrections for various noise components which appear in the measured flux. These result from coupling between the measuring loops and the toroidal and poloidal field windings, both directly and through currents induced in the vacuum vessel and coils themselves. An analysis of these couplings is made and techniques for correcting them developed. Results from the diamagnetic measurement, employing some of these correction techniques, are presented and compared with other data. The obtained values of β/sub I perpendicular to/ agree with those obtained from the equilibrium magnetic analysis (β/sub IΔ/) in ohmically heated plasmas, indicating no anisotropy. However, with 0.3 to 2.0 MW of tangential neutral beam injection, β/sub IΔ/ is consistently greater than β/sub I pependicular to/ and qualitatively consistent with the formation of an anisotropic ion velocity distribution and with toroidal rotation. Quantitatively, the difference between β/sub IΔ/ and β/sub I perpendicular to/ is more than can be accounted for on the basis of the usual classical fast ion calculations and spectroscopic rotation measurements

  20. Diamagnetic (cyclotron) resonance in semiconductors using strong magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Sosniak, J

    1962-07-01

    Diamagnetic (cyclotron) resonance experiments have been carried out in the semiconductors indium-antimonide (InSb), the indium-arsenide (InAs). Pulsed magnetic fields up to 300,000 gauss and monochromatic infrared radiation of 9 to 13.5 microns wavelength were used to measure the effective mass of the conduction electrons in those materials. The samples were n-type single crystals, with a room temperature electron concentration of 1.9 x 10{sup 16} and 6 x 10{sup 16} per cm{sup 3} in InSb and InAs respectively. Both the InSb and InAs samples showed a strong dependence of the effective mass on the magnetic field. The results show that the conduction bands in those solids are highly non-parabolic. Measurements were also made of the resonance absorption coefficients, which were found to be considerably smaller than the values obtained from simple theory. The effect is explained by assuming that the magnetic field reduces the intrinsic electron density, and that the absorption coefficient depends on the shape of the conduction band. It is postulated as a consequence that the relaxation time of diamagnetic energy levels at high magnetic fields does not differ appreciably from the relaxation time used in the description of conduction processes. (author)

  1. Diamagnetic effect in the foremoon solar wind observed by Kaguya

    Science.gov (United States)

    Nishino, Masaki N.; Saito, Yoshifumi; Tsunakawa, Hideo; Miyake, Yohei; Harada, Yuki; Yokota, Shoichiro; Takahashi, Futoshi; Matsushima, Masaki; Shibuya, Hidetoshi; Shimizu, Hisayoshi

    2017-04-01

    Direct interaction between the lunar surface and incident solar wind is one of the crucial phenomena of the planetary plasma sciences. Recent observations by lunar orbiters revealed that strength of the interplanetary magnetic field (IMF) at spacecraft altitude often increases over crustal magnetic fields on the dayside. In addition, variations of the IMF on the lunar night side have been reported in the viewpoint of diamagnetic effect around the lunar wake. However, few studies have been performed for the IMF over non-magnetized regions on the dayside. Here we show an event where strength of the IMF decreases at 100 km altitude on the lunar dayside (i.e. in the foremoon solar wind) when the IMF is almost parallel to the incident solar wind flow, comparing the upstream solar wind data from ACE with Kaguya magnetometer data. The lunar surface below the Kaguya orbit is not magnetized (or very weakly magnetized), and the sunward-travelling protons show signatures of those back-scattered at the lunar surface. We find that the decrease in the magnetic pressure is compensated by the thermal pressure of the back-scattered protons. In other words, the IMF strength in the foremoon solar wind decreases by diamagnetic effect of sunward-travelling protons back-scattered at the lunar dayside surface. Such an effect would be prominent in the high-beta solar wind, and may be ubiquitous in the environment where planetary surface directly interacts with surrounding space plasma.

  2. Spin and diamagnetism in linear and nonlinear optics

    International Nuclear Information System (INIS)

    Andersen, Torsten; Keller, Ole; Huebner, Wolfgang; Johansson, Boerje

    2004-01-01

    We present a local-field theory for spin and diamagnetism in linear and nonlinear optics. We examine all the processes contained in the Pauli Hamiltonian and its corresponding microscopic current density, including the terms depending on the electron spin. The resulting general real-space conductivities are presented and discussed. To quantify the implications of including the spin, we study the linear and nonlinear optical properties of free-electron metals, represented by the screened homogeneous electron gas. The real-space formalism is transformed into Fourier space, and the symmetries of the linear and nonlinear optical conductivities in a homogeneous electron gas are discussed. Numerical results are presented for the homogeneous electron gas, in which we treat ω and q as independent variables, thereby opening the theory to near-field optics and the study of evanescent waves. We show that in regions of the ω-q spectrum, the presence of diamagnetism and spin dynamics significantly alters the response in comparison to considering only the paramagnetic response. Additionally, we discuss the effects of screening, and we finish our treatment by a discussion of how to connect the present theory to existing methods in ab initio solid-state physics

  3. Chemistry of paramagnetic and diamagnetic contrast agents for Magnetic Resonance Imaging and Spectroscopy

    International Nuclear Information System (INIS)

    Perez-Mayoral, Elena; Negri, Viviana; Soler-Padros, Jordi; Cerdan, Sebastian; Ballesteros, Paloma

    2008-01-01

    We provide a brief overview of the chemistry and most relevant properties of paramagnetic and diamagnetic contrast agents (CAs) for Magnetic Resonance Imaging and Magnetic Resonance Spectroscopic Imaging. Paramagnetic CAs for MRI consist mainly of Gd(III) complexes from linear or macrocyclic polyaminopolycarboxylates. These agents reduce, the relaxation times T 1 and T 2 of the water protons in a concentration dependent manner, increasing selectively MRI contrast in those regions in which they accumulate. In most instances they provide anatomical information on the localization of lesions and in some specific cases they may allow to estimate some physiological properties of tissues including mainly vascular performance. Because of its ability to discriminate easily between normal and diseased tissue, extracellular pH (pH e ) has been added recently, to the battery of variables amenable to MRI investigation. A variety of Gd(III) containing macrocycles sensitive to pH, endogenous or exogenous polypeptides or even liposomes have been investigated for this purpose, using the pH dependence of their relaxivity or magnetization transfer rate constant (chemical exchange saturation transfer, CEST). Many environmental circumstances in addition to pH affect, however, relaxivity or magnetization transfer rate constants of these agents, making the results of pH measurements by MRI difficult to interpret. To overcome these limitations, our laboratory synthesized and developed a novel series of diamagnetic CAs for Magnetic Resonance Spectroscopic Imaging, a new family of monomeric and dimeric imidazolic derivatives able to provide unambiguous measurements of pH e , independent of water relaxivity, diffusion or exchange

  4. Chemistry of paramagnetic and diamagnetic contrast agents for Magnetic Resonance Imaging and Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Mayoral, Elena [Laboratorio de Sintesis Organica e Imagen Molecular por Resonancia Magnetica, Facultad de Ciencias, UNED, Paseo Senda del Rey 9, E-28040 Madrid (Spain); Departamento de Quimica Inorganica y Quimica Tecnica, Facultad de Ciencias, UNED, Paseo Senda del Rey 9, E-28040 Madrid (Spain); Negri, Viviana; Soler-Padros, Jordi [Laboratorio de Sintesis Organica e Imagen Molecular por Resonancia Magnetica, Facultad de Ciencias, UNED, Paseo Senda del Rey 9, E-28040 Madrid (Spain); Cerdan, Sebastian [Laboratorio de Imagen Espectroscopica por Resonancia Magnetica (LIERM), Instituto de Investigaciones Biomedicas ' Alberto Sols' , CSIC/UAM, c/Arturo Duperier 4, E-28029 Madrid (Spain); Ballesteros, Paloma [Laboratorio de Sintesis Organica e Imagen Molecular por Resonancia Magnetica, Facultad de Ciencias, UNED, Paseo Senda del Rey 9, E-28040 Madrid (Spain)], E-mail: pballesteros@ccia.uned.es

    2008-09-15

    We provide a brief overview of the chemistry and most relevant properties of paramagnetic and diamagnetic contrast agents (CAs) for Magnetic Resonance Imaging and Magnetic Resonance Spectroscopic Imaging. Paramagnetic CAs for MRI consist mainly of Gd(III) complexes from linear or macrocyclic polyaminopolycarboxylates. These agents reduce, the relaxation times T{sub 1} and T{sub 2} of the water protons in a concentration dependent manner, increasing selectively MRI contrast in those regions in which they accumulate. In most instances they provide anatomical information on the localization of lesions and in some specific cases they may allow to estimate some physiological properties of tissues including mainly vascular performance. Because of its ability to discriminate easily between normal and diseased tissue, extracellular pH (pH{sub e}) has been added recently, to the battery of variables amenable to MRI investigation. A variety of Gd(III) containing macrocycles sensitive to pH, endogenous or exogenous polypeptides or even liposomes have been investigated for this purpose, using the pH dependence of their relaxivity or magnetization transfer rate constant (chemical exchange saturation transfer, CEST). Many environmental circumstances in addition to pH affect, however, relaxivity or magnetization transfer rate constants of these agents, making the results of pH measurements by MRI difficult to interpret. To overcome these limitations, our laboratory synthesized and developed a novel series of diamagnetic CAs for Magnetic Resonance Spectroscopic Imaging, a new family of monomeric and dimeric imidazolic derivatives able to provide unambiguous measurements of pH{sub e}, independent of water relaxivity, diffusion or exchange.

  5. Exploitation of a diamagnetic loop for modulated ECH power absorption measurements in TCV

    International Nuclear Information System (INIS)

    Manini, A.; Moret, J.M.; Alberti, S.; Goodman, T.P.; Henderson, M.A.

    2003-01-01

    For the evaluation of the performance of auxiliary heating methods and for the understanding of the transport properties of auxiliary heated plasmas, it is of fundamental importance to determine the fraction of the launched power that is actually transferred to the plasma, as well as where in the plasma the power is deposited. The diagnostic which is probably the best suited for the first goal is the Diamagnetic Loop (DML) providing a measurement of the diamagnetic flux of the plasma, which is directly related to the total plasma kinetic energy. TCV is equipped with a very versatile Electron Cyclotron Heating (ECH) system. It consists of six gyrotrons operating at the second harmonic, 82.7 GHz, and three gyrotrons at the third harmonic, 118 GHz. The nominal power for each 82.7 GHz gyrotron is 465 kW and for each 118 GHz gyrotron is 480 kW, resulting in a total of radio frequency power of 4.2 MW. In this paper we present the method that has been developed for determining the absorbed power in the ECH experiments in TCV, pointing out especially the results of the first third harmonic X-Mode (X3) ECH experiments, leaving the problem of the power deposition localisation to other reports. For the determination of the total plasma kinetic energy, the DML has also been used on other devices such as JET, ASDEX and TEXTOR, but only for this last case modulation experiments have been performed and analysed. Modulated ECH has been used to determine the ECH X2 and X3 power absorption from the measurement of the diamagnetic flux variations using the DML. Since only the modulation contribution is relevant to the analysis, the method does not require a perfect compensation of the diamagnetic flux measurement, although a good compensation of the vessel poloidal image current is crucial for ensuring a sufficiently large bandwidth to allow the use of high frequency modulation. The analysis of the behaviour of the amplitude and phase response in the modulation frequency scan has

  6. Dynamical behavior of granular matter in low gravity (diamagnetic levitation)

    International Nuclear Information System (INIS)

    Brooks, J.S.; Cothern, J.A.

    2001-01-01

    We report studies on the dynamics of macroscopic particles in a low-gravity 'magnetic levitation' environment. In a real sense, this allows the investigation of new states of granular matter. Particle ensembles (rods, spheres, or grains) can be held in a weak confining potential due to diamagnetic forces in a high-field-resistive magnet. In such a case 'kT' is not zero, and assemblies of particles undergo ergodic processes to find the lowest configurational ground state. This new area presents unique problems for video data acquisition and mathematical descriptions of the complex dynamic motions, interactions, and configurations of single and multiple particle assemblies. Three examples of such processes are presented

  7. Dynamical behavior of granular matter in low gravity (diamagnetic levitation)

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, J.S. E-mail: brooks@magnet.fsu.edu; Cothern, J.A

    2001-05-01

    We report studies on the dynamics of macroscopic particles in a low-gravity 'magnetic levitation' environment. In a real sense, this allows the investigation of new states of granular matter. Particle ensembles (rods, spheres, or grains) can be held in a weak confining potential due to diamagnetic forces in a high-field-resistive magnet. In such a case 'kT' is not zero, and assemblies of particles undergo ergodic processes to find the lowest configurational ground state. This new area presents unique problems for video data acquisition and mathematical descriptions of the complex dynamic motions, interactions, and configurations of single and multiple particle assemblies. Three examples of such processes are presented.

  8. Dielectric and diamagnetic susceptibilities near percolative superconductor-insulator transitions.

    Science.gov (United States)

    Loh, Yen Lee; Karki, Pragalv

    2017-10-25

    Coarse-grained superconductor-insulator composites exhibit a superconductor-insulator transition governed by classical percolation, which should be describable by networks of inductors and capacitors. We study several classes of random inductor-capacitor networks on square lattices. We present a unifying framework for defining electric and magnetic response functions, and we extend the Frank-Lobb bond-propagation algorithm to compute these quantities by network reduction. We confirm that the superfluid stiffness scales approximately as [Formula: see text] as the superconducting bond fraction p approaches the percolation threshold p c . We find that the diamagnetic susceptibility scales as [Formula: see text] below percolation, and as [Formula: see text] above percolation. For models lacking self-capacitances, the electric susceptibility scales as [Formula: see text]. Including a self-capacitance on each node changes the critical behavior to approximately [Formula: see text].

  9. Fluctuation diamagnetism near surfaces and twinning planes in superconductors

    International Nuclear Information System (INIS)

    Burmistrov, S.N.; Dubovskii, L.B.

    1984-01-01

    Fluctuations of the magnetic moment and of the specific heat near surfaces and twinning planes in superconductors are studied. Fluctuations near a surface yield an additional contribution to the effect of the usual bulk fluctuations on the diamagnetic moment. Such an additional contribution has a singularity near a temperature T/sub c/3(H), which is higher than the bulk superconducting transition temperature in a magnetic field T/sub c/2(H). Depending on the strength of the magnetic field, the singularity of the additional contribution to the magnetic moment can be either logarithmic (strong fields) or of square-root type (weak fields). Experiments which could reveal the aforementioned anomalous behavior are discussed in detail

  10. Dental cavities

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/001055.htm Dental cavities To use the sharing features on this page, please enable JavaScript. Dental cavities are holes (or structural damage) in the ...

  11. Zero electrical resistance of perfect conductor and diamagnet

    International Nuclear Information System (INIS)

    Palaspagar, R.S.

    2012-01-01

    Intense research has taken place to discover new superconductors, to understand the physics that underlies the properties of superconductors, and to develop new applications for these materials. The fascinating phenomenon of superconductivity and its potential applications have attracted the attention of scientists, engineers and businessmen. In this paper we will discuss about the brief history of superconductors. And we will discuss also phenomenons of superconductors and the two different types of superconductor that exist today. We can say that superconductor exhibits infinite conductivity. A bulk specimen of metal in the superconducting state exhibits perfect diamagnetism, with the magnetic induction B=0 named as Meissner effect. It would have been very difficult to have arrived at the theory of superconductivity by purely deductive reasoning from the basic equations of quantum mechanics. A successful quantum theory of superconductivity has provided the basic for subsequent work and the importance of the phase of the superconducting wave function. If we could make a material that was superconducting at room temperature then our computers would work faster because they would allow electric currents to flow more easily. That would mean electric appliances in our homes and offices would waste much less power. We could also make 'Maglev' (magnetic levitation) trains that would float on rails using linear motors and get us around with a fraction of the power used by current locomotives. (author)

  12. Ultrasensitive Inertial and Force Sensors with Diamagnetically Levitated Magnets

    Science.gov (United States)

    Prat-Camps, J.; Teo, C.; Rusconi, C. C.; Wieczorek, W.; Romero-Isart, O.

    2017-09-01

    We theoretically show that a magnet can be stably levitated on top of a punctured superconductor sheet in the Meissner state without applying any external field. The trapping potential created by such induced-only superconducting currents is characterized for magnetic spheres ranging from tens of nanometers to tens of millimeters. Such a diamagnetically levitated magnet is predicted to be extremely well isolated from the environment. We propose to use it as an ultrasensitive force and inertial sensor. A magnetomechanical readout of its displacement can be performed by using superconducting quantum interference devices. An analysis using current technology shows that force and acceleration sensitivities on the order of 10-23 N /√{Hz } (for a 100-nm magnet) and 10-14 g /√{Hz } (for a 10-mm magnet) might be within reach in a cryogenic environment. Such remarkable sensitivities, both in force and acceleration, can be used for a variety of purposes, from designing ultrasensitive inertial sensors for technological applications (e.g., gravimetry, avionics, and space industry), to scientific investigations on measuring Casimir forces of magnetic origin and gravitational physics.

  13. Simultaneous influence of hydrostatic pressure and temperature on diamagnetic susceptibility of impurity doped quantum dots under the aegis of noise

    International Nuclear Information System (INIS)

    Saha, Surajit; Ganguly, Jayanta; Bera, Aindrila; Ghosh, Manas

    2016-01-01

    Highlights: • Diamagnetic susceptibility (DMS) of doped quantum dot is studied. • Hydrostatic pressure (HP) and temperature (T) affect DMS. • The dot is subjected to Gaussian white noise. • DMS also depends on mode of application of noise. - Abstract: We explore the diamagnetic susceptibility (DMS) of impurity doped quantum dot (QD) in presence of Gaussian white noise and under the combined influence of hydrostatic pressure (HP) and temperature (T). Presence of noise and also its mode of application discernibly affect the DMS profile. Application of HP and T invites greater delicacies in the observed DMS profiles. However, whereas the interplay between T and noise comes out to be extremely sensitive in fabricating the DMS profile, the pressure-noise interplay appears to be not that much noticeable. Under all conditions of temperature and pressure, the presence of multiplicative noise diminishes the value of DMS in comparison with that in presence of its additive analogue. The present study renders a deep insight into the remarkable role played by the interplay between noise, hydrostatic pressure and temperature in controlling the effective confinement imposed on the system which bears unquestionable relevance.

  14. Simultaneous influence of hydrostatic pressure and temperature on diamagnetic susceptibility of impurity doped quantum dots under the aegis of noise

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Surajit [Department of Chemistry, Physical Chemistry Section, Visva Bharati University, Santiniketan, Birbhum 731 235, West Bengal (India); Ganguly, Jayanta [Department of Chemistry, Brahmankhanda Basapara High School, Basapara, Birbhum 731215, West Bengal (India); Bera, Aindrila [Department of Chemistry, Physical Chemistry Section, Visva Bharati University, Santiniketan, Birbhum 731 235, West Bengal (India); Ghosh, Manas, E-mail: pcmg77@rediffmail.com [Department of Chemistry, Physical Chemistry Section, Visva Bharati University, Santiniketan, Birbhum 731 235, West Bengal (India)

    2016-11-30

    Highlights: • Diamagnetic susceptibility (DMS) of doped quantum dot is studied. • Hydrostatic pressure (HP) and temperature (T) affect DMS. • The dot is subjected to Gaussian white noise. • DMS also depends on mode of application of noise. - Abstract: We explore the diamagnetic susceptibility (DMS) of impurity doped quantum dot (QD) in presence of Gaussian white noise and under the combined influence of hydrostatic pressure (HP) and temperature (T). Presence of noise and also its mode of application discernibly affect the DMS profile. Application of HP and T invites greater delicacies in the observed DMS profiles. However, whereas the interplay between T and noise comes out to be extremely sensitive in fabricating the DMS profile, the pressure-noise interplay appears to be not that much noticeable. Under all conditions of temperature and pressure, the presence of multiplicative noise diminishes the value of DMS in comparison with that in presence of its additive analogue. The present study renders a deep insight into the remarkable role played by the interplay between noise, hydrostatic pressure and temperature in controlling the effective confinement imposed on the system which bears unquestionable relevance.

  15. Method of compensation spires for the detection of the diamagnetic effect in a Tokamak

    International Nuclear Information System (INIS)

    Colunga S, S.

    1990-09-01

    In this report the classical detection method of the diamagnetic effect by means of a rolled spire on the discharges chamber in the poloidal direction and the difficulties related with this are analyzed. An alternative method that increases considerably the detection sensibility of the diamagnetic effect and that for its simplicity it is quite attractive for its application to the Tokamak Novillo of the ININ is presented. (Author)

  16. accelerating cavity

    CERN Multimedia

    On the inside of the cavity there is a layer of niobium. Operating at 4.2 degrees above absolute zero, the niobium is superconducting and carries an accelerating field of 6 million volts per metre with negligible losses. Each cavity has a surface of 6 m2. The niobium layer is only 1.2 microns thick, ten times thinner than a hair. Such a large area had never been coated to such a high accuracy. A speck of dust could ruin the performance of the whole cavity so the work had to be done in an extremely clean environment.

  17. Transition from diamagnetic to ferromagnetic state in laser ablated nitrogen doped ZnO thin films

    Directory of Open Access Journals (Sweden)

    Kajal Jindal

    2015-02-01

    Full Text Available Transition from room temperature diamagnetic to ferromagnetic state in N doped ZnO (ZnO:N films grown by pulsed laser deposition with tunable energy density has been identified. ZnO:N films deposited with moderate laser energy density of 2.5 J/cm2 are single phase and nearly defect free having N dopant substitution at O sites in ZnO lattice, exhibiting intrinsic ferromagnetism. When energy density reduces (<2.5 J/cm2, defects in ZnO:N film degrades ferromagnetism and exhibit diamagnetic phase when grown at energy density of 1.0 J/cm2. Growth kinetics, which in turn depends on laser energy density is playing important role in making transition from ferromagnetic to diamagnetic in ZnO:N films.

  18. Numerical linear analysis of the effects of diamagnetic and shear flow on ballooning modes

    Science.gov (United States)

    Yanqing, HUANG; Tianyang, XIA; Bin, GUI

    2018-04-01

    The linear analysis of the influence of diamagnetic effect and toroidal rotation at the edge of tokamak plasmas with BOUT++ is discussed in this paper. This analysis is done by solving the dispersion relation, which is calculated through the numerical integration of the terms with different physics. This method is able to reveal the contributions of the different terms to the total growth rate. The diamagnetic effect stabilizes the ideal ballooning modes through inhibiting the contribution of curvature. The toroidal rotation effect is also able to suppress the curvature-driving term, and the stronger shearing rate leads to a stronger stabilization effect. In addition, through linear analysis using the energy form, the curvature-driving term provides the free energy absorbed by the line-bending term, diamagnetic term and convective term.

  19. radiofrequency cavity

    CERN Multimedia

    1988-01-01

    The pulse of a particle accelerator. 128 of these radio frequency cavities were positioned around CERN's 27-kilometre LEP ring to accelerate electrons and positrons. The acceleration was produced by microwave electric oscillations at 352 MHz. The electrons and positrons were grouped into bunches, like beads on a string, and the copper sphere at the top stored the microwave energy between the passage of individual bunches. This made for valuable energy savings as it reduced the heat generated in the cavity.

  20. Ab initio quantum chemical calculation as a tool of evaluating diamagnetic susceptibility of magnetically levitating substances

    Energy Technology Data Exchange (ETDEWEB)

    Fujiwara, Y [Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Tanimoto, Y [Faculty of Pharmacy, Osaka Ohtani University, Nishikiorikita, Tondabayashi 584-8540 (Japan)], E-mail: fuji0710@sci.hiroshima-u.ac.jp

    2009-03-01

    On magnetic force evaluation necessary for magnetically levitated diamagnetic substances, isotropic diamagnetic susceptibility estimation by the ab initio quantum chemical calculation using Gaussian03W was verified for more than 300 molecules in a viewpoint of the accuracy in the absolute value and the calculation level affording good cost performance. From comparison, the method of B3PW91 / 6-311+G(d,p) was found to give the adequate absolute value by the relation of (observed) = (1.03 {+-} 0.005) x (calculated) - (1.22 {+-} 0.60) x 10{sup -6} in a unit of cm{sup 3} mol{sup -1} and good cost performance.

  1. Ab initio quantum chemical calculation as a tool of evaluating diamagnetic susceptibility of magnetically levitating substances

    International Nuclear Information System (INIS)

    Fujiwara, Y; Tanimoto, Y

    2009-01-01

    On magnetic force evaluation necessary for magnetically levitated diamagnetic substances, isotropic diamagnetic susceptibility estimation by the ab initio quantum chemical calculation using Gaussian03W was verified for more than 300 molecules in a viewpoint of the accuracy in the absolute value and the calculation level affording good cost performance. From comparison, the method of B3PW91 / 6-311+G(d,p) was found to give the adequate absolute value by the relation of (observed) = (1.03 ± 0.005) x (calculated) - (1.22 ± 0.60) x 10 -6 in a unit of cm 3 mol -1 and good cost performance.

  2. Diamagnetic composite material structure for reducing undesired electromagnetic interference and eddy currents in dielectric wall accelerators and other devices

    Science.gov (United States)

    Caporaso, George J.; Poole, Brian R.; Hawkins, Steven A.

    2015-06-30

    The devices, systems and techniques disclosed here can be used to reduce undesired effects by magnetic field induced eddy currents based on a diamagnetic composite material structure including diamagnetic composite sheets that are separated from one another to provide a high impedance composite material structure. In some implementations, each diamagnetic composite sheet includes patterned conductor layers are separated by a dielectric material and each patterned conductor layer includes voids and conductor areas. The voids in the patterned conductor layers of each diamagnetic composite sheet are arranged to be displaced in position from one patterned conductor layer to an adjacent patterned conductor layer while conductor areas of the patterned conductor layers collectively form a contiguous conductor structure in each diamagnetic composite sheet to prevent penetration by a magnetic field.

  3. The diamagnetic susceptibility of a donor in a semiconductor core shell quantum dot

    Energy Technology Data Exchange (ETDEWEB)

    Sudharshan, M. S.; Subhash, P.; Shaik, Nagoor Babu [Department of Mechanical Engineering, Saveetha School of Engineering, Saveetha University, Thandalam, Chennai – 602105 (India); Kalpana, P.; Jayakumar, K. [Department of Physics, Gandhigram Rural University, Gandhigram, Tamilnadu-624302 (India); Reuben, A. Merwyn Jasper D., E-mail: merwyn@gmail.com [Department of Physics, Saveetha School of Engineering, Saveetha University, Thandalam, Chennai – 602105 (India)

    2015-06-24

    The effect of Aluminium concentration, shell thickness and size of the core shell Quantum Dot on the Diamagnetic Susceptibility of a donor in the Core Shell Quantum Dot is calculated in the effective mass approximation using the variational method. The results are presented and discussed.

  4. The diamagnetic susceptibility of a donor in a semiconductor core shell quantum dot

    Science.gov (United States)

    Sudharshan, M. S.; Subhash, P.; Shaik, Nagoor Babu; Kalpana, P.; Jayakumar, K.; Reuben, A. Merwyn Jasper D.

    2015-06-01

    The effect of Aluminium concentration, shell thickness and size of the core shell Quantum Dot on the Diamagnetic Susceptibility of a donor in the Core Shell Quantum Dot is calculated in the effective mass approximation using the variational method. The results are presented and discussed.

  5. Orbital diamagnetism of a charged Brownian particle undergoing birth-death process

    International Nuclear Information System (INIS)

    Jayannawar, A.M.; Kumar, N.

    1980-06-01

    We consider the magnetic response of a charged Brownian particle undergoing a stochastic birth-death process. The latter simulates the electron-hole pair production and recombination in semiconductors. We obtain non-zero, orbital diamagnetism which can be large without violating the Van Leeuwen theorem. (author)

  6. Understanding the Planck blackbody spectrum and Landau diamagnetism within classical electromagnetism

    International Nuclear Information System (INIS)

    Boyer, Timothy H

    2016-01-01

    Electromagnetism is a relativistic theory, and one must exercise care in coupling this theory with nonrelativistic classical mechanics and with nonrelativistic classical statistical mechanics. Indeed historically, both the blackbody radiation spectrum and diamagnetism within classical theory have been misunderstood because of two crucial failures: (1) the neglect of classical electromagnetic zero-point radiation, and (2) the use of erroneous combinations of nonrelativistic mechanics with relativistic electrodynamics. Here we review the treatment of classical blackbody radiation, and show that the presence of Lorentz-invariant classical electromagnetic zero-point radiation can explain both the Planck blackbody spectrum and Landau diamagnetism at thermal equilibrium within classical electromagnetic theory. The analysis requires that relativistic electromagnetism is joined appropriately with simple nonrelativistic mechanical systems which can be regarded as the zero-velocity limits of relativistic systems, and that nonrelativistic classical statistical mechanics is applied only in the low-frequency limit when zero-point energy makes no contribution. (paper)

  7. A low-frequency vibration energy harvester based on diamagnetic levitation

    Science.gov (United States)

    Kono, Yuta; Masuda, Arata; Yuan, Fuh-Gwo

    2017-04-01

    This article presents 3-degree-of-freedom theoretical modeling and analysis of a low-frequency vibration energy harvester based on diamagnetic levitation. In recent years, although much attention has been placed on vibration energy harvesting technologies, few harvesters still can operate efficiently at extremely low frequencies in spite of large potential demand in the field of structural health monitoring and wearable applications. As one of the earliest works, Liu, Yuan and Palagummi proposed vertical and horizontal diamagnetic levitation systems as vibration energy harvesters with low resonant frequencies. This study aims to pursue further improvement along this direction, in terms of expanding maximum amplitude and enhancing the flexibility of the operation direction for broader application fields by introducing a new topology of the levitation system.

  8. Monte Carlo studies of diamagnetism and charge density wave order in the cuprate pseudogap regime

    Science.gov (United States)

    Hayward Sierens, Lauren; Achkar, Andrew; Hawthorn, David; Melko, Roger; Sachdev, Subir

    2015-03-01

    The pseudogap regime of the hole-doped cuprate superconductors is often characterized experimentally in terms of a substantial diamagnetic response and, from another point of view, in terms of strong charge density wave (CDW) order. We introduce a dimensionless ratio, R, that incorporates both diamagnetic susceptibility and the correlation length of CDW order, and therefore reconciles these two fundamental characteristics of the pseudogap. We perform Monte Carlo simulations on a classical model that considers angular fluctuations of a six-dimensional order parameter, and compare our Monte Carlo results for R with existing data from torque magnetometry and x-ray scattering experiments on YBa2Cu3O6+x. We achieve qualitative agreement, and also propose future experiments to further investigate the behaviour of this dimensionless ratio.

  9. Modulated ECH power absorption measurements using a diamagnetic loop in the TCV tokamak

    International Nuclear Information System (INIS)

    Manini, A.; Moret, J.M.; Alberti, S.; Goodman, T.P.; Henderson, M.A.

    2001-10-01

    The additional power absorbed by the plasma can be determined from the time derivative of the total plasma energy, which can be estimated from the diamagnetic flux of the plasma using a Diamagnetic Loop (DML). The main difficulty in using diamagnetic measurements to estimate the kinetic energy is the compensation of the flux measurement sensitivity to poloidal magnetic fields, which is not always easy to adjust. A method based on the temporal variations of the diamagnetic flux of the plasma during Modulated Electron Cyclotron Heating (MECH) has been developed. Using MECH has the advantage that these poloidal fields are not significantly modulated and a good compensation of these fields is not necessary. However, a good compensation of the vessel poloidal image current is crucial to ensure a sufficiently large bandwidth. The application of this diagnostic to studies of the extraordinary mode (X-mode) absorption at the third electron cyclotron harmonic frequency (X3) has been performed on the TCV Tokamak in plasmas pre-heated by X-mode at the second harmonic (X2). A MECH frequency scan has allowed the determination of an optimum modulation frequency, situated at about 200- 250 Hz. Based on this diagnostic, full single-pass absorption of the injected X3 power was measured with the X2 pre-heating in co-current drive. This high absorption is more than a factor of 2 higher than the one predicted by the linear ray tracing code TORAY. Experimental evidence indicates that a large fraction of the X3 power is absorbed by electrons in an energetic tail created by the X2 pre-heating. (author)

  10. Modelling of diamagnetic stabilization of ideal MHD eigenmodes associated with the transport barrier

    International Nuclear Information System (INIS)

    Huysmans, G.; Sharapov, S.; Mikhailovskii, A.; Kerner, W.

    2001-01-01

    A new code, MISHKA-D (Drift MHD), has been developed as an extension of the ideal MHD code MISHKA-1 in order to investigate the finite gyroradius stabilizing effect of ion diamagnetic drift frequency, ω *i , on linear ideal MHD eigenmodes in tokamaks with shaped plasma cross-section. The MISHKA-D code gives a self-consistent computation of both stable and unstable eigenmodes with eigenvalues [γ] ≅ ω *i in plasmas with strong radial variation in the ion diamagnetic frequency. Test results of the MISHKA-D code show good agreement with the analytically obtained ω *i -spectrum and stability limits of the internal kink mode, n/m=1/1, used as a benchmark case. Finite-n ballooning and low-n kink (peeling) modes in the edge transport barrier just inside the separatrix are studied for H-mode plasma with the ω *i -effect included. The ion diamagnetic stabilization of the ballooning modes is found to be most effective for narrow edge pedestals. For low enough plasma density the ω *i - stabilization can lead to a second zone of ballooning stability, in which all the ballooning modes are stable for any value of the pressure gradient. For internal transport barriers typical of JET optimised shear discharges, the stabilizing influence of ion diamagnetic frequency on the n=1 global pressure driven disruptive mode is studied. A strong radial variation of ω *i is found to significantly decrease the stabilizing ω *i - effect on the n=1 mode, in comparison with the case of constant ω *i estimated at the foot of the internal transport barrier. (author)

  11. Simultaneous diamagnetic and magnetic particle trapping in ferrofluid microflows via a single permanent magnet.

    Science.gov (United States)

    Zhou, Yilong; Kumar, Dhileep Thanjavur; Lu, Xinyu; Kale, Akshay; DuBose, John; Song, Yongxin; Wang, Junsheng; Li, Dongqing; Xuan, Xiangchun

    2015-07-01

    Trapping and preconcentrating particles and cells for enhanced detection and analysis are often essential in many chemical and biological applications. Existing methods for diamagnetic particle trapping require the placement of one or multiple pairs of magnets nearby the particle flowing channel. The strong attractive or repulsive force between the magnets makes it difficult to align and place them close enough to the channel, which not only complicates the device fabrication but also restricts the particle trapping performance. This work demonstrates for the first time the use of a single permanent magnet to simultaneously trap diamagnetic and magnetic particles in ferrofluid flows through a T-shaped microchannel. The two types of particles are preconcentrated to distinct locations of the T-junction due to the induced negative and positive magnetophoretic motions, respectively. Moreover, they can be sequentially released from their respective trapping spots by simply increasing the ferrofluid flow rate. In addition, a three-dimensional numerical model is developed, which predicts with a reasonable agreement the trajectories of diamagnetic and magnetic particles as well as the buildup of ferrofluid nanoparticles.

  12. Simultaneous diamagnetic and magnetic particle trapping in ferrofluid microflows via a single permanent magnet

    Science.gov (United States)

    Zhou, Yilong; Kumar, Dhileep Thanjavur; Lu, Xinyu; Kale, Akshay; DuBose, John; Song, Yongxin; Wang, Junsheng; Li, Dongqing; Xuan, Xiangchun

    2015-01-01

    Trapping and preconcentrating particles and cells for enhanced detection and analysis are often essential in many chemical and biological applications. Existing methods for diamagnetic particle trapping require the placement of one or multiple pairs of magnets nearby the particle flowing channel. The strong attractive or repulsive force between the magnets makes it difficult to align and place them close enough to the channel, which not only complicates the device fabrication but also restricts the particle trapping performance. This work demonstrates for the first time the use of a single permanent magnet to simultaneously trap diamagnetic and magnetic particles in ferrofluid flows through a T-shaped microchannel. The two types of particles are preconcentrated to distinct locations of the T-junction due to the induced negative and positive magnetophoretic motions, respectively. Moreover, they can be sequentially released from their respective trapping spots by simply increasing the ferrofluid flow rate. In addition, a three-dimensional numerical model is developed, which predicts with a reasonable agreement the trajectories of diamagnetic and magnetic particles as well as the buildup of ferrofluid nanoparticles. PMID:26221197

  13. NMR study of local diamagnetic properties of carbon structures with multiwalled nanotubes

    International Nuclear Information System (INIS)

    Nikolaev, E.G.; Omel'yanovsky, O.E.; Prudkovsky, V.S.; Sadakov, A.V.; Tsebro, V.I.

    2009-01-01

    The reasons for the high diamagnetic susceptibility of carbon columns, which are covered with a nanotube mesh, from the interior part of cathode deposits have been studied by means of NMR. A comparative study is made of the 13 C NMR spectra and the magnetic susceptibility of carbon columns before and after ultrasonic processing as well as of finely dispersed material, obtained as a result of such processing, enriched with multilayer nanotubes. The strong diamagnetism of the carbon columns is apparently associated with a quite dense conglomerate of graphite particles, nanotubes, and multilayer polyhedral particles present in their core and not with the surface mesh of multilayer nanotubes. To make a more accurate determination of the character of the anisotropy of the magnetic susceptibility of multilayer carbon nanotubes, the form of the 13 C NMR spectra of samples enriched with multilayer nanotubes, where the nanotubes are either not oriented or only partially oriented, is analyzed. It is shown that the diamagnetic susceptibility of multilayer carbon nanotubes is highest when the magnetic field is oriented perpendicular to their axis

  14. Impurity States and diamagnetic susceptibility of a donor in a triangular quantum well

    Science.gov (United States)

    Kalpana, P.; Reuben, A. Merwyn Jasper D.; Nithiananthi, P.; Jayakumar, K.

    2017-05-01

    We have calculated the binding energy and the diamagnetic susceptibility(χdia) of the ground (1s) and few low lying excited states (2s and 2p±) in a GaAs/AlxGa1-xAs Triangular Quantum Well (TQW) for the Al composition of x = 0.3. Since the estimation of gives the carrier localization in nanostructured systems and also the calculation of (χdia) involves the , the same has also been estimated as a function of well width. The Schrodinger equation has been solved using variational technique involving Airy functions in the effective mass approximation. The results are presented and discussed.

  15. Experimental study on stabilizing range extension of diamagnetic levitation under modulated magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Chow, T C S; Wong, P L; Liu, K P, E-mail: 50578230@student.cityu.edu.h, E-mail: meplwong@cityu.edu.h, E-mail: mekpliu@cityu.edu.h [Manufacturing Engineering and Engineering Management Department, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong)

    2010-01-01

    The real energy-free levitation exists with the help of diamagnetic material. Its ultra-high sensitivity to force is particularly attractive to micro/nano force sensing. A key parameter: Levitation Stabilizing Local Range, LR (allowable moving range of the floater) is critical to the load and self-rotating performance. Besides, larger LR reduces the energy loss due to the eddy current and has greater application potential. Recently, an idea of extending the LR by a modulating coil array has been validated using numerical simulation. This paper takes the next move to carry out an experimental study on the shape effect of stacked coil arrays with different currents on LR.

  16. Coulomb scatter of diamagnetic dust particles in a cusp magnetic trap under microgravity conditions

    Energy Technology Data Exchange (ETDEWEB)

    Myasnikov, M. I., E-mail: miasnikovmi@mail.ru; D’yachkov, L. G.; Petrov, O. F.; Vasiliev, M. M., E-mail: mixxy@mail.ru; Fortov, V. E. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation); Savin, S. F.; Serova, E. O. [Korolev Rocket and Space Corporation Energia, ul. Lenina 4A (Russian Federation)

    2017-02-15

    The effect of a dc electric field on strongly nonideal Coulomb systems consisting of a large number (~10{sup 4}) of charged diamagnetic dust particles in a cusp magnetic trap are carried out aboard the Russian segment of the International Space Station (ISS) within the Coulomb Crystal experiment. Graphite particles of 100–400 μm in size are used in the experiments. Coulomb scatter of a dust cluster and the formation of threadlike chains of dust particles are observed experimentally. The processes observed are simulated by the molecular dynamics (MD) method.

  17. Diamagnetism of the B10H12L2 series compounds

    International Nuclear Information System (INIS)

    Volkov, V.V.; Ikorskij, V.N.; Dunaev, S.T.

    1988-01-01

    The method of static magnetic susceptibility is used to study diamagnetic susceptibilities of a number of B 10 H 12 L 2 (where L - nitrogen, sulfur, phosphorus-containing organic ligands) decaborane-derivatives and to draw the increment χ M -125 for the nido cluster (B 10 H 12 ) and boron atomic increment χ bar M -9.0 in this cluster. The absolute value χ B in (B 10 H 12 ) cluster is much higher than χ B for noncluster systems (2.7-7.6). This difference proves electron delocalization in (B 10 H 12 ) and the aromatic nature of this nido-cluster

  18. Theory and Simulations of Incomplete Reconnection During Sawteeth Due to Diamagnetic Effects

    Science.gov (United States)

    Beidler, Matthew Thomas

    Tokamaks use magnetic fields to confine plasmas to achieve fusion; they are the leading approach proposed for the widespread production of fusion energy. The sawtooth crash in tokamaks limits the core temperature, adversely impacts confinement, and seeds disruptions. Adequate knowledge of the physics governing the sawtooth crash and a predictive capability of its ramifications has been elusive, including an understanding of incomplete reconnection, i.e., why sawteeth often cease prematurely before processing all available magnetic flux. In this dissertation, we introduce a model for incomplete reconnection in sawtooth crashes resulting from increasing diamagnetic effects in the nonlinear phase of magnetic reconnection. Physically, the reconnection inflow self-consistently convects the high pressure core of a tokamak toward the q=1 rational surface, thereby increasing the pressure gradient at the reconnection site. If the pressure gradient at the rational surface becomes large enough due to the self-consistent evolution, incomplete reconnection will occur due to diamagnetic effects becoming large enough to suppress reconnection. Predictions of this model are borne out in large-scale proof-of-principle two-fluid simulations of reconnection in a 2D slab geometry and are also consistent with data from the Mega Ampere Spherical Tokamak (MAST). Additionally, we present simulations from the 3D extended-MHD code M3D-C1 used to study the sawtooth crash in a 3D toroidal geometry for resistive-MHD and two-fluid models. This is the first study in a 3D tokamak geometry to show that the inclusion of two-fluid physics in the model equations is essential for recovering timescales more closely in line with experimental results compared to resistive-MHD and contrast the dynamics in the two models. We use a novel approach to sample the data in the plane of reconnection perpendicular to the (m,n)=(1,1) mode to carefully assess the reconnection physics. Using local measures of

  19. Realization of Anisotropic Diamagnetic Kepler Problem in a Solid State Environment

    International Nuclear Information System (INIS)

    Chen Zhanghai; Zhou Weihang; Zhang Bo; Yu, C. H.; Zhu Jingbing; Lu Wei; Shen, S. C.

    2009-01-01

    The anisotropic diamagnetic Kepler problem (ADKP) is realized experimentally by the orbital electrons of a P donor in Si under magnetic fields. The interference of electron wave packets which leads to quasi-Landau resonances (QLR) were observed. Applying the closed-orbit theory to an anisotropic solid state environment, we have identified orbits responsible for the QLR manifesting the quantum chaotic behavior in Rydberg atoms. The excellent consistency between the measured spectra and theoretical calculation provides unambiguous evidence of quantum chaotic dynamics of electrons in the ADKP.

  20. Nonlinear Diamagnetic Stabilization of Double Tearing Modes in Cylindrical MHD Simulations

    Science.gov (United States)

    Abbott, Stephen; Germaschewski, Kai

    2014-10-01

    Double tearing modes (DTMs) may occur in reversed-shear tokamak configurations if two nearby rational surfaces couple and begin reconnecting. During the DTM's nonlinear evolution it can enter an ``explosive'' growth phase leading to complete reconnection, making it a possible driver for off-axis sawtooth crashes. Motivated by similarities between this behavior and that of the m = 1 kink-tearing mode in conventional tokamaks we investigate diamagnetic drifts as a possible DTM stabilization mechanism. We extend our previous linear studies of an m = 2 , n = 1 DTM in cylindrical geometry to the fully nonlinear regime using the MHD code MRC-3D. A pressure gradient similar to observed ITB profiles is used, together with Hall physics, to introduce ω* effects. We find the diamagnetic drifts can have a stabilizing effect on the nonlinear DTM through a combination of large scale differential rotation and mechanisms local to the reconnection layer. MRC-3D is an extended MHD code based on the libMRC computational framework. It supports nonuniform grids in curvilinear coordinates with parallel implicit and explicit time integration.

  1. Extend of magnetic field interference in the natural convection of diamagnetic nanofluid

    Science.gov (United States)

    Roszko, Aleksandra; Fornalik-Wajs, Elzbieta

    2017-10-01

    Main objective of the paper was to experimentally investigate the thermo-magnetic convection of diamagnetic fluids in the Rayleigh-Benard configuration. For better understanding of the magnetic field influence on the phenomena occurring in cubical enclosure the following parameters were studied: absence or presence of nanoparticles (single and two-phase fluids), thermal conditions (temperature difference range of 5-25 K) and magnetic field strength (magnetic induction range of 0-10 T). A multi-stage approach was undertaken to achieve the aim. The multi-stage approach means that the forces system, flow structure and heat transfer were considered. Without understanding the reasons (forces) and the fluid behaviour it would be impossible to analyse the exchanged heat rates through the Nusselt number distribution. The forces were determined at the starting moment, so the inertia force was not considered. The flow structure was identified due to the FFT analysis and it proved that magnetic field application changed the diamagnetic fluid behaviour, either single or two-phase. Going further, the heat transfer analysis revealed dependence of the Nusselt number on the flow structure and at the same time on the magnetic field. It can be said that imposed magnetic field changed the energy transfer within the system. In the paper, it was shown that each of presented steps were linked together and that only a comprehensive approach could lead to better understanding of magnetic field interference in the convection phenomenon.

  2. Statistical characteristics of trajectories of diamagnetic unicellular organisms in a magnetic field.

    Science.gov (United States)

    Gorobets, Yu I; Gorobets, O Yu

    2015-01-01

    The statistical model is proposed in this paper for description of orientation of trajectories of unicellular diamagnetic organisms in a magnetic field. The statistical parameter such as the effective energy is calculated on basis of this model. The resulting effective energy is the statistical characteristics of trajectories of diamagnetic microorganisms in a magnetic field connected with their metabolism. The statistical model is applicable for the case when the energy of the thermal motion of bacteria is negligible in comparison with their energy in a magnetic field and the bacteria manifest the significant "active random movement", i.e. there is the randomizing motion of the bacteria of non thermal nature, for example, movement of bacteria by means of flagellum. The energy of the randomizing active self-motion of bacteria is characterized by the new statistical parameter for biological objects. The parameter replaces the energy of the randomizing thermal motion in calculation of the statistical distribution. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Scaling of reactor cavity wall loads and stresses

    International Nuclear Information System (INIS)

    Bohachevsky, I.O.

    1977-11-01

    Scalings of reactor cavity wall loads and stresses are determined by deriving an analytic expression in terms of relevant parameters for each loading induced in the reactor cavity walls by fuel pellet microexplosion and by deriving associated expressions relating resulting stresses to shell thicknesses. Also identified are problems that require additional investigations to obtain satisfactory explicit stress estimates for the reactor cavity walls

  4. Magnetic field is the dominant factor to induce the response of Streptomyces avermitilis in altered gravity simulated by diamagnetic levitation.

    Directory of Open Access Journals (Sweden)

    Mei Liu

    Full Text Available BACKGROUND: Diamagnetic levitation is a technique that uses a strong, spatially varying magnetic field to simulate an altered gravity environment, as in space. In this study, using Streptomyces avermitilis as the test organism, we investigate whether changes in magnetic field and altered gravity induce changes in morphology and secondary metabolism. We find that a strong magnetic field (12T inhibit the morphological development of S. avermitilis in solid culture, and increase the production of secondary metabolites. METHODOLOGY/PRINCIPAL FINDINGS: S. avermitilis on solid medium was levitated at 0 g*, 1 g* and 2 g* in an altered gravity environment simulated by diamagnetic levitation and under a strong magnetic field, denoted by the asterix. The morphology was obtained by electromicroscopy. The production of the secondary metabolite, avermectin, was determined by OD(245 nm. The results showed that diamagnetic levitation could induce a physiological response in S. avermitilis. The difference between 1 g* and the control group grown without the strong magnetic field (1 g, showed that the magnetic field was a more dominant factor influencing changes in morphology and secondary metabolite production, than altered gravity. CONCLUSION/SIGNIFICANCE: We have discovered that magnetic field, rather than altered gravity, is the dominant factor in altered gravity simulated by diamagnetic levitation, therefore care should to be taken in the interpretation of results when using diamagnetic levitation as a technique to simulate altered gravity. Hence, these results are significant, and timely to researchers considering the use of diamagnetic levitation to explore effects of weightlessness on living organisms and on physical phenomena.

  5. Segmented trapped vortex cavity

    Science.gov (United States)

    Grammel, Jr., Leonard Paul (Inventor); Pennekamp, David Lance (Inventor); Winslow, Jr., Ralph Henry (Inventor)

    2010-01-01

    An annular trapped vortex cavity assembly segment comprising includes a cavity forward wall, a cavity aft wall, and a cavity radially outer wall there between defining a cavity segment therein. A cavity opening extends between the forward and aft walls at a radially inner end of the assembly segment. Radially spaced apart pluralities of air injection first and second holes extend through the forward and aft walls respectively. The segment may include first and second expansion joint features at distal first and second ends respectively of the segment. The segment may include a forward subcomponent including the cavity forward wall attached to an aft subcomponent including the cavity aft wall. The forward and aft subcomponents include forward and aft portions of the cavity radially outer wall respectively. A ring of the segments may be circumferentially disposed about an axis to form an annular segmented vortex cavity assembly.

  6. A Review of the Comparative Anatomy, Histology, Physiology and Pathology of the Nasal Cavity of Rats, Mice, Dogs and Non-human Primates. Relevance to Inhalation Toxicology and Human Health Risk Assessment.

    Science.gov (United States)

    Chamanza, R; Wright, J A

    2015-11-01

    There are many significant differences in the structural and functional anatomy of the nasal cavity of man and laboratory animals. Some of the differences may be responsible for the species-specific nasal lesions that are often observed in response to inhaled toxicants. This paper reviews the comparative anatomy, physiology and pathology of the nasal cavity of the rat, mouse, dog, monkey and man, highlighting factors that may influence the distribution of nasal lesions. Gross anatomical variations such as turbinate structure, folds or grooves on nasal walls, or presence or absence of accessory structures, may influence nasal airflow and species-specific uptake and deposition of inhaled material. In addition, interspecies variations in the morphological and biochemical composition and distribution of the nasal epithelium may affect the local tissue susceptibility and play a role in the development of species-specific nasal lesions. It is concluded that, while the nasal cavity of the monkey might be more similar to that of man, each laboratory animal species provides a model that responds in a characteristic and species-specific manner. Therefore for human risk assessment, careful consideration must be given to the anatomical differences between a given animal model and man. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Mirror nesting of the Fermi contour and enhanced diamagnetism of the pseudogap state in cuprates

    Energy Technology Data Exchange (ETDEWEB)

    Kapaev, V.V.; Belyavsky, V.I. [P.N. Lebedev Physical Institute of Russian Academy of Sciences, Moscow 119991 (Russian Federation); Kopaev, Yu.V. [P.N. Lebedev Physical Institute of Russian Academy of Sciences, Moscow 119991 (Russian Federation)], E-mail: kopaev@sci.lebedev.ru; Smirnov, M.Yu. [State Pedagogical University, Voronezh 394043 (Russian Federation)

    2007-09-01

    Since the insulating gap in parent spin antiferromagnet survives under a hole underdoping, it might result in a rise of a metal state with a pocket-like Fermi contour with both conventional and mirror nesting corresponding to the same momentum K = ({pi}, {pi}). The nesting leads to a possibility of singlet orbital antiferromagnetic order whereas the mirror nesting promotes the superconducting pairing with the momentum K. We assume screened Coulomb repulsion to be the dominating pairing interaction in the cuprates resulting in the two-component superconducting order parameter. The relative phase of the parameter can be related to orbital current circulations as it follows from the Ginzburg-Landau phenomenology. The orbital antiferromagnetic state with the insulating gap on the Fermi contour is related to the pseudogap state with enhanced diamagnetic response.

  8. Note on de Haas-van Alphen diamagnetism in thin, free-electron films

    Directory of Open Access Journals (Sweden)

    J. A. Grzesik

    2012-03-01

    Full Text Available We revisit the problem of de Haas-van Alphen (dHvA diamagnetic susceptibility oscillations in a thin, free-electron film trapped in a synthetic harmonic potential well. A treatment of this phenomenon at zero temperature was announced many years ago by Childers and Pincus (designated hereafter as CP, and we traverse initially much the same ground, but from a slightly different analytic perspective. That difference hinges around our use, in calculating the Helmholtz free energy F, of an inverse Laplace transform, Bromwich-type contour integral representation for the sharp distribution cutoff at Fermi level μ. The contour integral permits closed-form summation all at once over the discrete orbital Landau energy levels transverse to the magnetic field, and the energy associated with the in-plane canonical momenta ℏ k x and ℏ k z. Following such summation/integration, pole/residue pairs appear in the plane of complex transform variable s, a fourth-order pole at origin s = 0, and an infinite ladder, both up and down, of simple poles along the imaginary axis. The residue sum from the infinite pole ladder automatically engenders a Fourier series with period one in dimensionless variable μ/ ℏ ω (with effective angular frequency ω suitably defined, series which admits closed-form summation as a cubic polynomial within any given periodicity slot. Such periodicity corresponds to Landau levels slipping sequentially beneath Fermi level μ as the ambient magnetic field H declines in strength, and is manifested by the dHvA pulsations in diamagnetic susceptibility. The coëxisting steady contribution from the pole at origin has a similar cubic structure but is opposite in sign, inducing a competition whose outcome is a net magnetization that is merely quadratic in any given periodicity slot, modulated by a slow amplitude growth. Apart from some minor notes of passing discord, these simple algebraic structures confirm most of the CP formulae, and their

  9. Gas viscosity measurement with diamagnetic-levitation viscometer based on electromagnetically spinning system.

    Science.gov (United States)

    Shimokawa, Y; Matsuura, Y; Hirano, T; Sakai, K

    2016-12-01

    Utilizing a graphite-disk probe attached with a thin aluminum disk, we have developed a friction-free viscosity measurement system. The probe is levitated above a NdFeB magnet because of diamagnetic effect and rotated by an electromagnetically induced torque. The probe is absolutely free form mechanical friction, and therefore, the accurate measurements of the viscosity of gases can be achieved. To demonstrate the accuracy and sensitivity of our method, we measured the viscosity of 8 kinds of gases and its temperature change from 278 K to 318 K, and we confirmed a good agreement between the obtained values and literature values. This paper demonstrates that our method has the ability to measure the fluid viscosity in the order of μPa ⋅ s.

  10. Mirror nesting of the Fermi contour and enhanced diamagnetism of the pseudogap state in cuprates

    International Nuclear Information System (INIS)

    Kapaev, V.V.; Belyavsky, V.I.; Kopaev, Yu.V.; Smirnov, M.Yu.

    2007-01-01

    Since the insulating gap in parent spin antiferromagnet survives under a hole underdoping, it might result in a rise of a metal state with a pocket-like Fermi contour with both conventional and mirror nesting corresponding to the same momentum K = (π, π). The nesting leads to a possibility of singlet orbital antiferromagnetic order whereas the mirror nesting promotes the superconducting pairing with the momentum K. We assume screened Coulomb repulsion to be the dominating pairing interaction in the cuprates resulting in the two-component superconducting order parameter. The relative phase of the parameter can be related to orbital current circulations as it follows from the Ginzburg-Landau phenomenology. The orbital antiferromagnetic state with the insulating gap on the Fermi contour is related to the pseudogap state with enhanced diamagnetic response

  11. Analytic simulation of the Poincare surface of sections for the diamagnetic Kepler problem

    International Nuclear Information System (INIS)

    Hasegawa, H.; Harada, A.; Okazaki, Y.

    1984-01-01

    The Poincare surface-of-section analysis which the authors previously reported on the diamagnetic Kepler problem (classical hydrogen atom in a uniform magnetic field) in a transition region from regular to chaotic motions is simulated by an analytic means, by taking intersections of the energy integral and the approximate integral Λ of Solovev to obtain sections of the two separate regions of the motion that exist in the limit of a weak magnetic field (B → 0). The origin of the unique hyperbolic point and the separatrix around which the onset of chaos takes place are thus identified. The invariant tori arising near the full chaos are shown to be simulated by this method but with modified parameter values in the expression Λ. (author)

  12. Gas viscosity measurement with diamagnetic-levitation viscometer based on electromagnetically spinning system

    Science.gov (United States)

    Shimokawa, Y.; Matsuura, Y.; Hirano, T.; Sakai, K.

    2016-12-01

    Utilizing a graphite-disk probe attached with a thin aluminum disk, we have developed a friction-free viscosity measurement system. The probe is levitated above a NdFeB magnet because of diamagnetic effect and rotated by an electromagnetically induced torque. The probe is absolutely free form mechanical friction, and therefore, the accurate measurements of the viscosity of gases can be achieved. To demonstrate the accuracy and sensitivity of our method, we measured the viscosity of 8 kinds of gases and its temperature change from 278 K to 318 K, and we confirmed a good agreement between the obtained values and literature values. This paper demonstrates that our method has the ability to measure the fluid viscosity in the order of μPa ṡ s.

  13. Analytic simulation of the Poincare surface of sections for the diamagnetic Kepler problem

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, H; Harada, A; Okazaki, Y [Kyoto Univ. (Japan). Dept. of Physics

    1984-11-11

    The Poincare surface-of-section analysis which the authors previously reported on the diamagnetic Kepler problem (classical hydrogen atom in a uniform magnetic field) in a transition region from regular to chaotic motions is simulated by an analytic means, by taking intersections of the energy integral and the approximate integral ..lambda.. of Solovev to obtain sections of the two separate regions of the motion that exist in the limit of a weak magnetic field (B ..-->.. 0). The origin of the unique hyperbolic point and the separatrix around which the onset of chaos takes place are thus identified. The invariant tori arising near the full chaos are shown to be simulated by this method but with modified parameter values in the expression ..lambda...

  14. Design of a low temperature translation balance for the measurement of paramagnetic and diamagnetic susceptibilities

    Energy Technology Data Exchange (ETDEWEB)

    Mowry, G.S.

    1979-05-01

    A modified Foex and Forrer Translation Balance has been designed for measuring the paramagnetic and diamagnetic properties of materials over the temperature range 77-300/sup 0/K. The systems' temperature range can eventually be extended to 4.2/sup 0/K. The apparatus incorporates a vertical Dewar of Standard variety in addition to a horizontal Dewar for cooling the sample holder and adjacent horizontal supports. The design also allows for the placement of a thermocouple junction in direct contact with a sample. The balance sensitivity, defined as the change in displacement per unit applied force, is 0.0044 cm/dyne. The precision of the balance is +- .5% with an accuracy of 1.5%.

  15. Co–Fe Prussian Blue Analogue Intercalated into Diamagnetic Mg–Al Layered Double Hydroxides

    Directory of Open Access Journals (Sweden)

    Cuijuan Zhang

    2016-04-01

    Full Text Available A heterostructure of diamagnetic magnesium‒aluminium layered double hydroxides (Mg‒Al LDHs and photomag‐ netic cobalt‒iron Prussian Blue analogue (Co‒Fe PBA was designed, synthesized and then designated as LDH‒PB. The cyanide-bridged Co‒Fe PBA was two-dimensionally intercalated into the Mg‒Al LDH template by the stepwise anion exchange method. LDH‒PB showed ferrimagnetic properties with in-plane antiferromagnetic exchange interactions, as well as small photo-induced magnetization by visible light illumination due to the low dimensional structures and the characteristic photo-induced electronic states of the mixed valence of FeIII(low spin, S = 1/2‒CN‒ CoII(high spin, S = 3/2‒NC‒FeII (low spin, S = 0.

  16. Diamagnetic measurement of JFT-2 plasma heated by neutral beam injection

    International Nuclear Information System (INIS)

    Maeno, Masaki; Sengoku, Seio; Yamamoto, Shin; Suzuki, Norio; Yamauchi, Toshihiko; Kawashima, Hisato; Miura, Yukitoshi

    1984-01-01

    A neutral beam was injected into the plasma in the JFT-2 tokamak, and the poloidal beta value βsub(p) of the plasma was determined by a diamagnetic method in which the change in the magnetic flux due to the plasma was obtained by measuring the very small perturbation of the current in the tokamak's toroidal field coil. The ratio of the perturbed to unperturbed currents in the coil was found to be (2-3) x 10 -4 . The poloidal beta value βsub(pd) determined by this method agrees within experimental error with that obtained from magnetic and energy profile analyses. βsub(pd) increases linearly with the total power Psub(net) deposited by the neutral beam in the plasma when Psub(net)=1.5 MW. The heating efficiency of the beam injection heating was found to be lower than that of Joule heating. (author)

  17. Faraday rotation dispersion microscopy imaging of diamagnetic and chiral liquids with pulsed magnetic field.

    Science.gov (United States)

    Suwa, Masayori; Nakano, Yusuke; Tsukahara, Satoshi; Watarai, Hitoshi

    2013-05-21

    We have constructed an experimental setup for Faraday rotation dispersion imaging and demonstrated the performance of a novel imaging principle. By using a pulsed magnetic field and a polarized light synchronized to the magnetic field, quantitative Faraday rotation images of diamagnetic organic liquids in glass capillaries were observed. Nonaromatic hydrocarbons, benzene derivatives, and naphthalene derivatives were clearly distinguished by the Faraday rotation images due to the difference in Verdet constants. From the wavelength dispersion of the Faraday rotation images in the visible region, it was found that the resonance wavelength in the UV region, which was estimated based on the Faraday B-term, could be used as characteristic parameters for the imaging of the liquids. Furthermore, simultaneous acquisition of Faraday rotation image and natural optical rotation image was demonstrated for chiral organic liquids.

  18. Magnetic bistability of isolated giant-spin centers in a diamagnetic crystalline matrix.

    Science.gov (United States)

    Vergnani, Luca; Barra, Anne-Laure; Neugebauer, Petr; Rodriguez-Douton, Maria Jesus; Sessoli, Roberta; Sorace, Lorenzo; Wernsdorfer, Wolfgang; Cornia, Andrea

    2012-03-12

    Polynuclear single-molecule magnets (SMMs) were diluted in a diamagnetic crystal lattice to afford arrays of independent and iso-oriented magnetic units. Crystalline solid solutions of an Fe(4) SMM and its Ga(4) analogue were prepared with no metal scrambling for Fe(4) molar fractions x down to 0.01. According to high-frequency EPR and magnetic measurements, the guest SMM species have the same total spin (S=5), anisotropy, and high-temperature spin dynamics found in the pure Fe(4) phase. However, suppression of intermolecular magnetic interactions affects magnetic relaxation at low temperature (40 mK), where quantum tunneling (QT) of the magnetization dominates. When a magnetic field is applied along the easy magnetic axis, both pure and diluted (x=0.01) phases display pronounced steps at evenly spaced field values in their hysteresis loops due to resonant QT. The pure Fe(4) phase exhibits additional steps which are firmly ascribed to two-molecule QT transitions. Studies on the field-dependent relaxation rate showed that the zero-field resonance sharpens by a factor of five and shifts from about 8 mT to exactly zero field on dilution, in agreement with the calculated variation of dipolar interactions. The tunneling efficiency also changes significantly as a function of Fe(4) concentration: the zero-field resonance is significantly enhanced on dilution, while tunneling at ±0.45 T becomes less efficient. These changes were rationalized on the basis of a dipolar shuffling mechanism and transverse dipolar fields, whose effect was analyzed by using a multispin model. Our findings directly prove the impact of intermolecular magnetic couplings on SMM behavior and disclose the magnetic response of truly isolated giant spins in a diamagnetic crystalline environment. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Diamagnetism to ferromagnetism in Sr-substituted epitaxial BaTiO{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Singamaneni, Srinivasa Rao, E-mail: ssingam@ncsu.edu; Prater, John T. [Materials Science Division, Army Research Office, Research Triangle Park, North Carolina 27709 (United States); Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Punugupati, Sandhyarani; Narayan, Jagdish [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States)

    2016-04-04

    We report on the ferromagnetic-like behavior in otherwise diamagnetic BaTiO{sub 3} (BTO) thin films upon doping with non-magnetic element Sr having the composition Ba{sub 0.4}Sr{sub 0.6}TiO{sub 3} (BST). The epitaxial integration of BST (∼800 nm) thick films on Si (100) substrate was achieved using MgO (40 nm) and TiN (20 nm) as buffer layers to prepare BST/MgO/TiN/Si (100) heterostructure by pulsed laser deposition. The c-axis oriented and cube-on-cube epitaxial BST is formed on Si (100) as evidenced by the in-plane and out-of-plane X-ray diffraction. All the deposited films are relaxed through domain matching epitaxy paradigm as observed from X-ray diffraction pattern and A{sub 1}TO{sub 3} mode (at 521.27 cm{sup −1}) of Raman spectra. As-deposited BST thin films reveal ferromagnetic-like properties, which persist up to 400 K. The magnetization decreases two-fold upon oxygen annealing. In contrast, as-deposited un-doped BTO films show diamagnetism. Electron spin resonance measurements reveal no evidence of external magnetic impurities. XRD and X-ray photoelectron spectroscopy spectra show significant changes influenced by Sr doping in BTO. The ferromagnetic-like behavior in BST could be due to the trapped electron donors from oxygen vacancies resulting from Sr-doping.

  20. G-factors and diamagnetic coefficients of electrons, holes, and excitons in InAs/InP quantum dots

    NARCIS (Netherlands)

    Bree, van J.; Silov, A.Yu.; Koenraad, P.M.; Flatté, M.E.; Pryor, C.E.

    2012-01-01

    The electron, hole, and exciton g factors and diamagnetic coefficients have been calculated using envelope-function theory for cylindrical InAs/InP quantum dots in the presence of a magnetic field parallel to the dot symmetry axis. A clear connection is established between the electron g factor and

  1. Nb3Sn for Radio Frequency Cavities

    International Nuclear Information System (INIS)

    Godeke, A.

    2006-01-01

    In this article, the suitability of Nb3Sn to improve the performance of superconducting Radio-Frequency (RF) cavities is discussed. The use of Nb3Sn in RF cavities is recognized as an enabling technology to retain a very high cavity quality factor (Q0) at 4.2 K and to significantly improve the cavity accelerating efficiency per unit length (Eacc). This potential arises through the fundamental properties of Nb3Sn. The properties that are extensively characterized in the literature are, however, mainly related to improvements in current carrying capacity (Jc) in the vortex state. Much less is available for the Meissner state, which is of key importance to cavities. Relevant data, available for the Meissner state is summarized, and it is shown how this already validates the use of Nb3Sn. In addition, missing knowledge is highlighted and suggestions are given for further Meissner state specific research

  2. Improved reactor cavity

    International Nuclear Information System (INIS)

    Katz, L.R.; Demarchais, W.E.

    1984-01-01

    A reactor pressure vessel disposed in a cavity has coolant inlet or outlet pipes extending through passages in the cavity walls and welded to pressure nozzles. The cavity wall has means for directing fluid away from a break at a weld away from the pressure vessel, and means for inhibiting flow of fluid toward the vessel. (author)

  3. Current correlations for the transport of interacting electrons through parallel quantum dots in a photon cavity

    Science.gov (United States)

    Gudmundsson, Vidar; Abdullah, Nzar Rauf; Sitek, Anna; Goan, Hsi-Sheng; Tang, Chi-Shung; Manolescu, Andrei

    2018-06-01

    We calculate the current correlations for the steady-state electron transport through multi-level parallel quantum dots embedded in a short quantum wire, that is placed in a non-perfect photon cavity. We account for the electron-electron Coulomb interaction, and the para- and diamagnetic electron-photon interactions with a stepwise scheme of configuration interactions and truncation of the many-body Fock spaces. In the spectral density of the temporal current-current correlations we identify all the transitions, radiative and non-radiative, active in the system in order to maintain the steady state. We observe strong signs of two types of Rabi oscillations.

  4. On interstellar light polarization by diamagnetic silicate and carbon dust in the infrared

    Science.gov (United States)

    Papoular, R.

    2018-04-01

    The motion of diamagnetic dust particles in interstellar magnetic fields is studied numerically with several different sets of parameters. Two types of behaviour are observed, depending on the value of the critical number R, which is a function of the grain inertia, the magnetic susceptibility of the material and of the strength of rotation braking. If R ≤ 10, the grain ends up in a static state and perfectly aligned with the magnetic field, after a few braking times. If not, it goes on precessing and nutating about the field vector for a much longer time. Usual parameters are such that the first situation can hardly be observed. Fortunately, in the second and more likely situation, there remains a persistent partial alignment that is far from negligible, although it decreases as the field decreases and as R increases. The solution of the complete equations of motion of grains in a field helps understanding the details of this behaviour. One particular case of an ellipsoidal forsterite silicate grain is studied in detail and shown to polarize light in agreement with astronomical measurements of absolute polarization in the infrared. Phonons are shown to contribute to the progressive flattening of extinction and polarization towards long wavelengths. The measured dielectric properties of forsterite qualitatively fit the Serkowski peak in the visible.

  5. Exciton diamagnetic shift and optical properties in CdSe nanocrystal quantum dots in magnetic fields

    Science.gov (United States)

    Wu, Shudong; Cheng, Liwen

    2018-04-01

    The magnetic field dependence of the optical properties of CdSe nanocrystal quantum dots (NQDs) is investigated theoretically using a perturbation method within the effective-mass approximation. The results show that the magnetic field lifts the degeneracy of the electron (hole) states. A blue-shift in the absorption spectra of m ≥ 0 exciton states is observed while the absorption peak of m attributed to the interplay of the orbital Zeeman effect and the additive confinement induced by the magnetic field. The excitonic absorption coefficient is almost independent of B in the strong confinement regime. The applied magnetic field causes the splitting of degenerated exciton states, resulting in the new absorption peaks. Based on the first-order perturbation theory, we propose the analytical expressions for the exciton binding energy, exciton transition energy and exciton diamagnetic shift of 1s, 1p-1, 1p0, 1p1, 1d-2, 1d-1, 1d0, 1d1, 1d2 and 2s exciton states on the applied magnetic field in the strong confinement regime.

  6. Ultimate Cavity Dynamics of Hydrophobic Spheres Impacting on Free Water Surfaces

    KAUST Repository

    Mansoor, Mohammad M.

    2012-01-01

    Cavity formation resulting from the water-entry of solid objects has been the subject of extensive research owing to its practical relevance in naval, military, industrial, sports and biological applications. The cavity formed by an impacting

  7. The LHC superconducting cavities

    CERN Document Server

    Boussard, Daniel; Häbel, E; Kindermann, H P; Losito, R; Marque, S; Rödel, V; Stirbet, M

    1999-01-01

    The LHC RF system, which must handle high intensity (0.5 A d.c.) beams, makes use of superconducting single-cell cavities, best suited to minimizing the effects of periodic transient beam loading. There will be eight cavities per beam, each capable of delivering 2 MV (5 MV/m accelerating field) at 400 MHz. The cavities themselves are now being manufactured by industry, using niobium-on-copper technology which gives full satisfaction at LEP. A cavity unit includes a helium tank (4.5 K operating temperature) built around a cavity cell, RF and HOM couplers and a mechanical tuner, all housed in a modular cryostat. Four-unit modules are ultimately foreseen for the LHC (two per beam), while at present a prototype version with two complete units is being extensively tested. In addition to a detailed description of the cavity and its ancillary equipment, the first test results of the prototype will be reported.

  8. LEP copper accelerating cavities

    CERN Multimedia

    Laurent Guiraud

    1999-01-01

    These copper cavities were used to generate the radio frequency electric field that was used to accelerate electrons and positrons around the 27-km Large Electron-Positron (LEP) collider at CERN, which ran from 1989 to 2000. The copper cavities were gradually replaced from 1996 with new superconducting cavities allowing the collision energy to rise from 90 GeV to 200 GeV by mid-1999.

  9. Method of compensation spires for the detection of the diamagnetic effect in a Tokamak; Metodo de espiras de compensacion para la deteccion del efecto diamagnetico en un Tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Colunga S, S

    1990-09-15

    In this report the classical detection method of the diamagnetic effect by means of a rolled spire on the discharges chamber in the poloidal direction and the difficulties related with this are analyzed. An alternative method that increases considerably the detection sensibility of the diamagnetic effect and that for its simplicity it is quite attractive for its application to the Tokamak Novillo of the ININ is presented. (Author)

  10. Basic principles of RF superconductivity and superconducting cavities

    OpenAIRE

    Schmüser, P

    2006-01-01

    The basics of superconductivity are outlined with special emphasis on the features which are relevant for the application of superconductors in radio frequency cavities for particle acceleration. For a cylindrical resonator (“pill box cavity”) the electromagnetic field in the cavity and important parameters such as resonance frequency, quality factor and shunt impedance are calculated analytically. The design and performance of practical cavities is shortly addressed.

  11. Efficient Characterization of Protein Cavities within Molecular Simulation Trajectories: trj_cavity.

    Science.gov (United States)

    Paramo, Teresa; East, Alexandra; Garzón, Diana; Ulmschneider, Martin B; Bond, Peter J

    2014-05-13

    Protein cavities and tunnels are critical in determining phenomena such as ligand binding, molecular transport, and enzyme catalysis. Molecular dynamics (MD) simulations enable the exploration of the flexibility and conformational plasticity of protein cavities, extending the information available from static experimental structures relevant to, for example, drug design. Here, we present a new tool (trj_cavity) implemented within the GROMACS ( www.gromacs.org ) framework for the rapid identification and characterization of cavities detected within MD trajectories. trj_cavity is optimized for usability and computational efficiency and is applicable to the time-dependent analysis of any cavity topology, and optional specialized descriptors can be used to characterize, for example, protein channels. Its novel grid-based algorithm performs an efficient neighbor search whose calculation time is linear with system size, and a comparison of performance with other widely used cavity analysis programs reveals an orders-of-magnitude improvement in the computational cost. To demonstrate its potential for revealing novel mechanistic insights, trj_cavity has been used to analyze long-time scale simulation trajectories for three diverse protein cavity systems. This has helped to reveal, respectively, the lipid binding mechanism in the deep hydrophobic cavity of a soluble mite-allergen protein, Der p 2; a means for shuttling carbohydrates between the surface-exposed substrate-binding and catalytic pockets of a multidomain, membrane-proximal pullulanase, PulA; and the structural basis for selectivity in the transmembrane pore of a voltage-gated sodium channel (NavMs), embedded within a lipid bilayer environment. trj_cavity is available for download under an open-source license ( http://sourceforge.net/projects/trjcavity ). A simplified, GROMACS-independent version may also be compiled.

  12. Rate constants for the slow Mu + propane abstraction reaction at 300 K by diamagnetic RF resonance.

    Science.gov (United States)

    Fleming, Donald G; Cottrell, Stephen P; McKenzie, Iain; Ghandi, Khashayar

    2015-08-14

    The study of kinetic isotope effects for H-atom abstraction rates by incident H-atoms from the homologous series of lower mass alkanes (CH4, C2H6 and, here, C3H8) provides important tests of reaction rate theory on polyatomic systems. With a mass of only 0.114 amu, the most sensitive test is provided by the rates of the Mu atom. Abstraction of H by Mu can be highly endoergic, due to the large zero-point energy shift in the MuH bond formed, which also gives rise to high activation energies from similar zero-point energy corrections at the transition state. Rates are then far too slow near 300 K to be measured by conventional TF-μSR techniques that follow the disappearance of the spin-polarised Mu atom with time. Reported here is the first measurement of a slow Mu reaction rate in the gas phase by the technique of diamagnetic radio frequency (RF) resonance, where the amplitude of the MuH product formed in the Mu + C3H8 reaction is followed with time. The measured rate constant, kMu = (6.8 ± 0.5) × 10(-16) cm(3) s(-1) at 300 K, is surprisingly only about a factor of three slower than that expected for H + C3H8, indicating a dominant contribution from quantum tunneling in the Mu reaction, consistent with elementary transition state theory calculations of the kMu/kH kinetic isotope effect.

  13. NMR shielding calculations across the periodic table: diamagnetic uranium compounds. 2. Ligand and metal NMR.

    Science.gov (United States)

    Schreckenbach, Georg

    2002-12-16

    In this and a previous article (J. Phys. Chem. A 2000, 104, 8244), the range of application for relativistic density functional theory (DFT) is extended to the calculation of nuclear magnetic resonance (NMR) shieldings and chemical shifts in diamagnetic actinide compounds. Two relativistic DFT methods are used, ZORA ("zeroth-order regular approximation") and the quasirelativistic (QR) method. In the given second paper, NMR shieldings and chemical shifts are calculated and discussed for a wide range of compounds. The molecules studied comprise uranyl complexes, [UO(2)L(n)](+/-)(q); UF(6); inorganic UF(6) derivatives, UF(6-n)Cl(n), n = 0-6; and organometallic UF(6) derivatives, UF(6-n)(OCH(3))(n), n = 0-5. Uranyl complexes include [UO(2)F(4)](2-), [UO(2)Cl(4)](2-), [UO(2)(OH)(4)](2-), [UO(2)(CO(3))(3)](4-), and [UO(2)(H(2)O)(5)](2+). For the ligand NMR, moderate (e.g., (19)F NMR chemical shifts in UF(6-n)Cl(n)) to excellent agreement [e.g., (19)F chemical shift tensor in UF(6) or (1)H NMR in UF(6-n)(OCH(3))(n)] has been found between theory and experiment. The methods have been used to calculate the experimentally unknown (235)U NMR chemical shifts. A large chemical shift range of at least 21,000 ppm has been predicted for the (235)U nucleus. ZORA spin-orbit appears to be the most accurate method for predicting actinide metal chemical shifts. Trends in the (235)U NMR chemical shifts of UF(6-n)L(n) molecules are analyzed and explained in terms of the calculated electronic structure. It is argued that the energy separation and interaction between occupied and virtual orbitals with f-character are the determining factors.

  14. Cavity design programs

    International Nuclear Information System (INIS)

    Nelson, E.M.

    1996-01-01

    Numerous computer programs are available to help accelerator physicists and engineers model and design accelerator cavities and other microwave components. This article discusses the problems these programs solve and the principles upon which these programs are based. Some examples of how these programs are used in the design of accelerator cavities are also given

  15. Cavity quantum electrodynamics

    International Nuclear Information System (INIS)

    Walther, Herbert; Varcoe, Benjamin T H; Englert, Berthold-Georg; Becker, Thomas

    2006-01-01

    This paper reviews the work on cavity quantum electrodynamics of free atoms. In recent years, cavity experiments have also been conducted on a variety of solid-state systems resulting in many interesting applications, of which microlasers, photon bandgap structures and quantum dot structures in cavities are outstanding examples. Although these phenomena and systems are very interesting, discussion is limited here to free atoms and mostly single atoms because these systems exhibit clean quantum phenomena and are not disturbed by a variety of other effects. At the centre of our review is the work on the one-atom maser, but we also give a survey of the entire field, using free atoms in order to show the large variety of problems dealt with. The cavity interaction can be separated into two main regimes: the weak coupling in cavity or cavity-like structures with low quality factors Q and the strong coupling when high-Q cavities are involved. The weak coupling leads to modification of spontaneous transitions and level shifts, whereas the strong coupling enables one to observe a periodic exchange of photons between atoms and the radiation field. In this case, atoms and photons are entangled, this being the basis for a variety of phenomena observed, some of them leading to interesting applications in quantum information processing. The cavity experiments with free atoms reached a new domain with the advent of experiments in the visible spectral region. A review on recent achievements in this area is also given

  16. Formation of coronal cavities

    International Nuclear Information System (INIS)

    An, C.H.; Suess, S.T.; Tandberg-Hanssen, E.; Steinolfson, R.S.

    1986-01-01

    A theoretical study of the formation of a coronal cavity and its relation to a quiescent prominence is presented. It is argued that the formation of a cavity is initiated by the condensation of plasma which is trapped by the coronal magnetic field in a closed streamer and which then flows down to the chromosphere along the field lines due to lack of stable magnetic support against gravity. The existence of a coronal cavity depends on the coronal magnetic field strength; with low strength, the plasma density is not high enough for condensation to occur. Furthermore, we suggest that prominence and cavity material is supplied from the chromospheric level. Whether a coronal cavity and a prominence coexist depends on the magnetic field configuration; a prominence requires stable magnetic support

  17. Electroluminescence Caused by the Transport of Interacting Electrons through Parallel Quantum Dots in a Photon Cavity

    Science.gov (United States)

    Gudmundsson, Vidar; Abdulla, Nzar Rauf; Sitek, Anna; Goan, Hsi-Sheng; Tang, Chi-Shung; Manolescu, Andrei

    2018-02-01

    We show that a Rabi-splitting of the states of strongly interacting electrons in parallel quantum dots embedded in a short quantum wire placed in a photon cavity can be produced by either the para- or the dia-magnetic electron-photon interactions when the geometry of the system is properly accounted for and the photon field is tuned close to a resonance with the electron system. We use these two resonances to explore the electroluminescence caused by the transport of electrons through the one- and two-electron ground states of the system and their corresponding conventional and vacuum electroluminescense as the central system is opened up by coupling it to external leads acting as electron reservoirs. Our analysis indicates that high-order electron-photon processes are necessary to adequately construct the cavity-photon dressed electron states needed to describe both types of electroluminescence.

  18. SPS RF Accelerating Cavity

    CERN Multimedia

    1979-01-01

    This picture shows one of the 2 new cavities installed in 1978-1979. The main RF-system of the SPS comprises four cavities: two of 20 m length and two of 16.5 m length. They are all installed in one long straight section (LSS 3). These cavities are of the travelling-wave type operating at a centre frequency of 200.2 MHz. They are wideband, filling time about 700 ns and untuned. The power amplifiers, using tetrodes are installed in a surface building 200 m from the cavities. Initially only two cavities were installed, a third cavity was installed in 1978 and a forth one in 1979. The number of power amplifiers was also increased: to the first 2 MW plant a second 2 MW plant was added and by end 1979 there were 8 500 kW units combined in pairs to feed each of the 4 cavities with up to about 1 MW RF power, resulting in a total accelerating voltage of about 8 MV. See also 7412016X, 7412017X, 7411048X

  19. Cavity characterization for general use in linear electron accelerators

    International Nuclear Information System (INIS)

    Souza Neto, M.V. de.

    1985-01-01

    The main objective of this work is to is to develop measurement techniques for the characterization of microwave cavities used in linear electron accelerators. Methods are developed for the measurement of parameters that are essential to the design of an accelerator structure using conventional techniques of resonant cavities at low power. Disk-loaded cavities were designed and built, similar to those in most existing linear electron accelerators. As a result, the methods developed and the estimated accuracy were compared with those from other investigators. The results of this work are relevant for the design of cavities with the objective of developing linear electron accelerators. (author) [pt

  20. Superconducting TESLA cavities

    Directory of Open Access Journals (Sweden)

    B. Aune

    2000-09-01

    Full Text Available The conceptional design of the proposed linear electron-positron collider TESLA is based on 9-cell 1.3 GHz superconducting niobium cavities with an accelerating gradient of E_{acc}≥25 MV/m at a quality factor Q_{0}≥5×10^{9}. The design goal for the cavities of the TESLA Test Facility (TTF linac was set to the more moderate value of E_{acc}≥15 MV/m. In a first series of 27 industrially produced TTF cavities the average gradient at Q_{0}=5×10^{9} was measured to be 20.1±6.2 MV/m, excluding a few cavities suffering from serious fabrication or material defects. In the second production of 24 TTF cavities, additional quality control measures were introduced, in particular, an eddy-current scan to eliminate niobium sheets with foreign material inclusions and stringent prescriptions for carrying out the electron-beam welds. The average gradient of these cavities at Q_{0}=5×10^{9} amounts to 25.0±3.2 MV/m with the exception of one cavity suffering from a weld defect. Hence only a moderate improvement in production and preparation techniques will be needed to meet the ambitious TESLA goal with an adequate safety margin. In this paper we present a detailed description of the design, fabrication, and preparation of the TESLA Test Facility cavities and their associated components and report on cavity performance in test cryostats and with electron beam in the TTF linac. The ongoing research and development towards higher gradients is briefly addressed.

  1. Cavity-enhanced spectroscopies

    CERN Document Server

    van Zee, Roger

    2003-01-01

    ""Cavity-Enhanced Spectroscopy"" discusses the use of optical resonators and lasers to make sensitive spectroscopic measurements. This volume is written by the researcchers who pioneered these methods. The book reviews both the theory and practice behind these spectroscopic tools and discusses the scientific discoveries uncovered by these techniques. It begins with a chapter on the use of optical resonators for frequency stabilization of lasers, which is followed by in-depth chapters discussing cavity ring-down spectroscopy, frequency-modulated, cavity-enhanced spectroscopy, intracavity spectr

  2. Tuned optical cavity magnetometer

    Science.gov (United States)

    Okandan, Murat; Schwindt, Peter

    2010-11-02

    An atomic magnetometer is disclosed which utilizes an optical cavity formed from a grating and a mirror, with a vapor cell containing an alkali metal vapor located inside the optical cavity. Lasers are used to magnetically polarize the alkali metal vapor and to probe the vapor and generate a diffracted laser beam which can be used to sense a magnetic field. Electrostatic actuators can be used in the magnetometer for positioning of the mirror, or for modulation thereof. Another optical cavity can also be formed from the mirror and a second grating for sensing, adjusting, or stabilizing the position of the mirror.

  3. Hydroforming of elliptical cavities

    Science.gov (United States)

    Singer, W.; Singer, X.; Jelezov, I.; Kneisel, P.

    2015-02-01

    Activities of the past several years in developing the technique of forming seamless (weldless) cavity cells by hydroforming are summarized. An overview of the technique developed at DESY for the fabrication of single cells and multicells of the TESLA cavity shape is given and the major rf results are presented. The forming is performed by expanding a seamless tube with internal water pressure while simultaneously swaging it axially. Prior to the expansion the tube is necked at the iris area and at the ends. Tube radii and axial displacements are computer controlled during the forming process in accordance with results of finite element method simulations for necking and expansion using the experimentally obtained strain-stress relationship of tube material. In cooperation with industry different methods of niobium seamless tube production have been explored. The most appropriate and successful method is a combination of spinning or deep drawing with flow forming. Several single-cell niobium cavities of the 1.3 GHz TESLA shape were produced by hydroforming. They reached accelerating gradients Eacc up to 35 MV /m after buffered chemical polishing (BCP) and up to 42 MV /m after electropolishing (EP). More recent work concentrated on fabrication and testing of multicell and nine-cell cavities. Several seamless two- and three-cell units were explored. Accelerating gradients Eacc of 30 - 35 MV /m were measured after BCP and Eacc up to 40 MV /m were reached after EP. Nine-cell niobium cavities combining three three-cell units were completed at the company E. Zanon. These cavities reached accelerating gradients of Eacc=30 - 35 MV /m . One cavity is successfully integrated in an XFEL cryomodule and is used in the operation of the FLASH linear accelerator at DESY. Additionally the fabrication of bimetallic single-cell and multicell NbCu cavities by hydroforming was successfully developed. Several NbCu clad single-cell and double-cell cavities of the TESLA shape have been

  4. Hydroforming of elliptical cavities

    Directory of Open Access Journals (Sweden)

    W. Singer

    2015-02-01

    Full Text Available Activities of the past several years in developing the technique of forming seamless (weldless cavity cells by hydroforming are summarized. An overview of the technique developed at DESY for the fabrication of single cells and multicells of the TESLA cavity shape is given and the major rf results are presented. The forming is performed by expanding a seamless tube with internal water pressure while simultaneously swaging it axially. Prior to the expansion the tube is necked at the iris area and at the ends. Tube radii and axial displacements are computer controlled during the forming process in accordance with results of finite element method simulations for necking and expansion using the experimentally obtained strain-stress relationship of tube material. In cooperation with industry different methods of niobium seamless tube production have been explored. The most appropriate and successful method is a combination of spinning or deep drawing with flow forming. Several single-cell niobium cavities of the 1.3 GHz TESLA shape were produced by hydroforming. They reached accelerating gradients E_{acc} up to 35  MV/m after buffered chemical polishing (BCP and up to 42  MV/m after electropolishing (EP. More recent work concentrated on fabrication and testing of multicell and nine-cell cavities. Several seamless two- and three-cell units were explored. Accelerating gradients E_{acc} of 30–35  MV/m were measured after BCP and E_{acc} up to 40  MV/m were reached after EP. Nine-cell niobium cavities combining three three-cell units were completed at the company E. Zanon. These cavities reached accelerating gradients of E_{acc}=30–35  MV/m. One cavity is successfully integrated in an XFEL cryomodule and is used in the operation of the FLASH linear accelerator at DESY. Additionally the fabrication of bimetallic single-cell and multicell NbCu cavities by hydroforming was successfully developed. Several NbCu clad single-cell and

  5. Microgravity simulation by diamagnetic levitation: effects of a strong gradient magnetic field on the transcriptional profile of Drosophila melanogaster

    Directory of Open Access Journals (Sweden)

    Herranz Raul

    2012-02-01

    Full Text Available Abstract Background Many biological systems respond to the presence or absence of gravity. Since experiments performed in space are expensive and can only be undertaken infrequently, Earth-based simulation techniques are used to investigate the biological response to weightlessness. A high gradient magnetic field can be used to levitate a biological organism so that its net weight is zero. Results We have used a superconducting magnet to assess the effect of diamagnetic levitation on the fruit fly D. melanogaster in levitation experiments that proceeded for up to 22 consecutive days. We have compared the results with those of similar experiments performed in another paradigm for microgravity simulation, the Random Positioning Machine (RPM. We observed a delay in the development of the fruit flies from embryo to adult. Microarray analysis indicated changes in overall gene expression of imagoes that developed from larvae under diamagnetic levitation, and also under simulated hypergravity conditions. Significant changes were observed in the expression of immune-, stress-, and temperature-response genes. For example, several heat shock proteins were affected. We also found that a strong magnetic field, of 16.5 Tesla, had a significant effect on the expression of these genes, independent of the effects associated with magnetically-induced levitation and hypergravity. Conclusions Diamagnetic levitation can be used to simulate an altered effective gravity environment in which gene expression is tuned differentially in diverse Drosophila melanogaster populations including those of different age and gender. Exposure to the magnetic field per se induced similar, but weaker, changes in gene expression.

  6. Enhancing the effective energy barrier of a Dy(III) SMM using a bridged diamagnetic Zn(II) ion.

    Science.gov (United States)

    Upadhyay, Apoorva; Singh, Saurabh Kumar; Das, Chinmoy; Mondol, Ranajit; Langley, Stuart K; Murray, Keith S; Rajaraman, Gopalan; Shanmugam, Maheswaran

    2014-08-18

    Field induced single-molecule-magnet behaviour is observed for both a heterodinuclear [ZnDy(L(-))2](3+) complex (1) and a mononuclear [Dy(HL)2](3+) complex (2), with effective energy barriers of 83 cm(-1) and 16 cm(-1), respectively. Insights into the relaxation mechanism(s) and barrier heights are provided via ab initio and DFT calculations. Our findings reveal an interesting observation that the U(eff) of SMMs can be enhanced by incorporating diamagnetic metal ions.

  7. Influence of a transverse magnetic field on arc root movements in a dc plasma torch: Diamagnetic effect of arc column

    International Nuclear Information System (INIS)

    Kim, Keun Su

    2009-01-01

    The effect of a transverse magnetic field on the anodic arc root movement inside a dc plasma torch has been investigated. The arc voltage fluctuation, which represents the degree of the arc instability, was reduced to 28.6% of the original value and the high frequency components in the voltage signal also decreased in their magnitudes. The inherent arc instability in a dc thermal plasma torch seems to be suppressed by a diamagnetic effect of the arc column. Furthermore, the measured voltage wave forms indicated that the arc root attachment mode would be controllable by a transverse magnetic field

  8. Nonlinear Analysis of Cavities in Rock Salt

    DEFF Research Database (Denmark)

    Ottosen, N. S.; Krenk, Steen

    1979-01-01

    The paper covers some material and computational aspects of the rock mechanics of leached cavities in salt. A material model is presented in which the instantaneous stiffness of the salt is obtained by interpolation between the unloaded state and a relevant failure state. The model enables predic...... prediction of short term triaxial behaviour from uniaxial stress-strain curves. Key results from a nonlinear finite element calculation of a gas-filled cavity are given, and the general features are related to a simple nonlinear method of stress evaluation....

  9. SPS accelerating cavity

    CERN Multimedia

    CERN PhotoLab

    1976-01-01

    The SPS started up with 2 accelerating cavities (each consisting of 5 tank sections) in LSS3. They have a 200 MHz travelling wave structure (see 7411032 and 7802190) and 750 kW of power is fed to each of the cavities from a 1 MW tetrode power amplifier, located in a surface building above, via a coaxial transmission line. Clemens Zettler, builder of the SPS RF system, is standing at the side of one of the cavities. In 1978 and 1979 another 2 cavities were added and entered service in 1980. These were part of the intensity improvement programme and served well for the new role of the SPS as proton-antiproton collider. See also 7411032, 8011289, 8104138, 8302397.

  10. Dental Sealants Prevent Cavities

    Science.gov (United States)

    ... Digital Press Kit Read the MMWR Science Clips Dental Sealants Prevent Cavities Effective protection for children Language: ... more use of sealants and reimbursement of services. Dental care providers can Apply sealants to children at ...

  11. Statistical electromagnetics: Complex cavities

    NARCIS (Netherlands)

    Naus, H.W.L.

    2008-01-01

    A selection of the literature on the statistical description of electromagnetic fields and complex cavities is concisely reviewed. Some essential concepts, for example, the application of the central limit theorem and the maximum entropy principle, are scrutinized. Implicit assumptions, biased

  12. accelerating cavity from LEP

    CERN Multimedia

    This is an accelerating cavity from LEP, with a layer of niobium on the inside. Operating at 4.2 degrees above absolute zero, the niobium is superconducting and carries an accelerating field of 6 million volts per metre with negligible losses. Each cavity has a surface of 6 m2. The niobium layer is only 1.2 microns thick, ten times thinner than a hair. Such a large area had never been coated to such a high accuracy. A speck of dust could ruin the performance of the whole cavity so the work had to be done in an extremely clean environment. These challenging requirements pushed European industry to new achievements. 256 of these cavities are now used in LEP to double the energy of the particle beams.

  13. Hybrid vertical cavity laser

    DEFF Research Database (Denmark)

    Chung, Il-Sug; Mørk, Jesper

    2010-01-01

    A new hybrid vertical cavity laser structure for silicon photonics is suggested and numerically investigated. It incorporates a silicon subwavelength grating as a mirror and a lateral output coupler to a silicon ridge waveguide.......A new hybrid vertical cavity laser structure for silicon photonics is suggested and numerically investigated. It incorporates a silicon subwavelength grating as a mirror and a lateral output coupler to a silicon ridge waveguide....

  14. The Superconducting TESLA Cavities

    CERN Document Server

    Aune, B.; Bloess, D.; Bonin, B.; Bosotti, A.; Champion, M.; Crawford, C.; Deppe, G.; Dwersteg, B.; Edwards, D.A.; Edwards, H.T.; Ferrario, M.; Fouaidy, M.; Gall, P-D.; Gamp, A.; Gössel, A.; Graber, J.; Hubert, D.; Hüning, M.; Juillard, M.; Junquera, T.; Kaiser, H.; Kreps, G.; Kuchnir, M.; Lange, R.; Leenen, M.; Liepe, M.; Lilje, L.; Matheisen, A.; Möller, W-D.; Mosnier, A.; Padamsee, H.; Pagani, C.; Pekeler, M.; Peters, H-B.; Peters, O.; Proch, D.; Rehlich, K.; Reschke, D.; Safa, H.; Schilcher, T.; Schmüser, P.; Sekutowicz, J.; Simrock, S.; Singer, W.; Tigner, M.; Trines, D.; Twarowski, K.; Weichert, G.; Weisend, J.; Wojtkiewicz, J.; Wolff, S.; Zapfe, K.

    2000-01-01

    The conceptional design of the proposed linear electron-positron colliderTESLA is based on 9-cell 1.3 GHz superconducting niobium cavities with anaccelerating gradient of Eacc >= 25 MV/m at a quality factor Q0 > 5E+9. Thedesign goal for the cavities of the TESLA Test Facility (TTF) linac was set tothe more moderate value of Eacc >= 15 MV/m. In a first series of 27industrially produced TTF cavities the average gradient at Q0 = 5E+9 wasmeasured to be 20.1 +- 6.2 MV/m, excluding a few cavities suffering fromserious fabrication or material defects. In the second production of 24 TTFcavities additional quality control measures were introduced, in particular aneddy-current scan to eliminate niobium sheets with foreign material inclusionsand stringent prescriptions for carrying out the electron-beam welds. Theaverage gradient of these cavities at Q0 = 5E+9 amounts to 25.0 +- 3.2 MV/mwith the exception of one cavity suffering from a weld defect. Hence only amoderate improvement in production and preparation technique...

  15. Fast Excitation and Photon Emission of a Single-Atom-Cavity System

    International Nuclear Information System (INIS)

    Bochmann, J.; Muecke, M.; Langfahl-Klabes, G.; Erbel, C.; Weber, B.; Specht, H. P.; Moehring, D. L.; Rempe, G.

    2008-01-01

    We report on the fast excitation of a single atom coupled to an optical cavity using laser pulses that are much shorter than all other relevant processes. The cavity frequency constitutes a control parameter that allows the creation of single photons in a superposition of two tunable frequencies. Each photon emitted from the cavity thus exhibits a pronounced amplitude modulation determined by the oscillatory energy exchange between the atom and the cavity. Our technique constitutes a versatile tool for future quantum networking experiments

  16. Video Toroid Cavity Imager

    Energy Technology Data Exchange (ETDEWEB)

    Gerald, Rex E. II; Sanchez, Jairo; Rathke, Jerome W.

    2004-08-10

    A video toroid cavity imager for in situ measurement of electrochemical properties of an electrolytic material sample includes a cylindrical toroid cavity resonator containing the sample and employs NMR and video imaging for providing high-resolution spectral and visual information of molecular characteristics of the sample on a real-time basis. A large magnetic field is applied to the sample under controlled temperature and pressure conditions to simultaneously provide NMR spectroscopy and video imaging capabilities for investigating electrochemical transformations of materials or the evolution of long-range molecular aggregation during cooling of hydrocarbon melts. The video toroid cavity imager includes a miniature commercial video camera with an adjustable lens, a modified compression coin cell imager with a fiat circular principal detector element, and a sample mounted on a transparent circular glass disk, and provides NMR information as well as a video image of a sample, such as a polymer film, with micrometer resolution.

  17. Metasurface external cavity laser

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Luyao, E-mail: luyaoxu.ee@ucla.edu; Curwen, Christopher A.; Williams, Benjamin S. [Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States); California NanoSystems Institute, University of California, Los Angeles, California 90095 (United States); Hon, Philip W. C.; Itoh, Tatsuo [Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States); Chen, Qi-Sheng [Northrop Grumman Aerospace Systems, Redondo Beach, California 90278 (United States)

    2015-11-30

    A vertical-external-cavity surface-emitting-laser is demonstrated in the terahertz range, which is based upon an amplifying metasurface reflector composed of a sub-wavelength array of antenna-coupled quantum-cascade sub-cavities. Lasing is possible when the metasurface reflector is placed into a low-loss external cavity such that the external cavity—not the sub-cavities—determines the beam properties. A near-Gaussian beam of 4.3° × 5.1° divergence is observed and an output power level >5 mW is achieved. The polarized response of the metasurface allows the use of a wire-grid polarizer as an output coupler that is continuously tunable.

  18. Earth-ionosphere cavity

    International Nuclear Information System (INIS)

    Tran, A.; Polk, C.

    1976-01-01

    To analyze ELF wave propagation in the earth-ionosphere cavity, a flat earth approximation may be derived from the exact equations, which are applicable to the spherical cavity, by introducing a second-order or Debye approximation for the spherical Hankel functions. In the frequency range 3 to 30 Hz, however, the assumed conditions for the Debye approximation are not satisfied. For this reason an exact evaluation of the spherical Hankel functions is used to study the effects of the flat earth approximation on various propagation and resonance parameters. By comparing the resonance equation for a spherical cavity with its flat earth counterpart and by assuming that the surface impedance Z/sub i/ at the upper cavity boundary is known, the relation between the eigenvalue ν and S/sub v/, the sine of the complex angle of incidence at the lower ionosphere boundary, is established as ν(ν + 1) = (kaS/sub v/) 2 . It is also shown that the approximation ν(ν + 1) approximately equals (ν + 1/2) 2 which was used by some authors is not adequate below 30 Hz. Numerical results for both spherical and planar stratification show that (1) planar stratification is adequate for the computation of the lowest three ELF resonance frequencies to within 0.1 Hz; (2) planar stratification will lead to errors in cavity Q and wave attenuation which increase with frequency; (3) computation of resonance frequencies to within 0.1 Hz requires the extension of the lower boundary of the ionosphere to a height where the ratio of conduction current to displacement current, (sigma/ωepsilon 0 ), is less than 0.3; (4) atmospheric conductivity should be considered down to ground level in computing cavity Q and wave attenuation

  19. Materials for superconducting cavities

    International Nuclear Information System (INIS)

    Bonin, B.

    1996-01-01

    The ideal material for superconducting cavities should exhibit a high critical temperature, a high critical field, and, above all, a low surface resistance. Unfortunately, these requirements can be conflicting and a compromise has to be found. To date, most superconducting cavities for accelerators are made of niobium. The reasons for this choice are discussed. Thin films of other materials such as NbN, Nb 3 Sn, or even YBCO compounds can also be envisaged and are presently investigated in various laboratories. It is shown that their success will depend critically on the crystalline perfection of these films. (author)

  20. Experimental investigation of cavity flows

    Energy Technology Data Exchange (ETDEWEB)

    Loeland, Tore

    1999-12-31

    This thesis uses LDV (Laser Doppler Velocimetry), PIV (Particle Image Velocimetry) and Laser Sheet flow Visualisation to study flow inside three different cavity configurations. For sloping cavities, the vortex structure inside the cavities is found to depend upon the flow direction past the cavity. The shape of the downstream corner is a key factor in destroying the boundary layer flow entering the cavity. The experimental results agree well with numerical simulations of the same geometrical configurations. The results of the investigations are used to find the influence of the cavity flow on the accuracy of the ultrasonic flowmeter. A method to compensate for the cavity velocities is suggested. It is found that the relative deviation caused by the cavity velocities depend linearly on the pipe flow. It appears that the flow inside the cavities should not be neglected as done in the draft for the ISO technical report on ultrasonic flowmeters. 58 refs., 147 figs., 2 tabs.

  1. Experimental investigation of cavity flows

    Energy Technology Data Exchange (ETDEWEB)

    Loeland, Tore

    1998-12-31

    This thesis uses LDV (Laser Doppler Velocimetry), PIV (Particle Image Velocimetry) and Laser Sheet flow Visualisation to study flow inside three different cavity configurations. For sloping cavities, the vortex structure inside the cavities is found to depend upon the flow direction past the cavity. The shape of the downstream corner is a key factor in destroying the boundary layer flow entering the cavity. The experimental results agree well with numerical simulations of the same geometrical configurations. The results of the investigations are used to find the influence of the cavity flow on the accuracy of the ultrasonic flowmeter. A method to compensate for the cavity velocities is suggested. It is found that the relative deviation caused by the cavity velocities depend linearly on the pipe flow. It appears that the flow inside the cavities should not be neglected as done in the draft for the ISO technical report on ultrasonic flowmeters. 58 refs., 147 figs., 2 tabs.

  2. Multipactors in klystron cavities

    International Nuclear Information System (INIS)

    Hayashi, Kazutaka; Iyeki, Hiroshi; Kikunaga, Toshiyuki.

    1993-01-01

    A multipactor phenomenon in a klystron causes gain shortage or instability problem. Some tests using a prototype klystron input cavity revealed the microwave discharges in vacuum with magnetic field. The test results and the methods to avoid multipactors are discussed in this paper. (author)

  3. What's a Cavity?

    Science.gov (United States)

    ... and deeper over time. Cavities are also called dental caries (say: KARE-eez), and if you have a ... made up mostly of the germs that cause tooth decay. The bacteria in your mouth make acids and when plaque clings to your teeth, the acids can eat away at the outermost ...

  4. Vertical cavity laser

    DEFF Research Database (Denmark)

    2016-01-01

    The present invention provides a vertical cavity laser comprising a grating layer comprising an in-plane grating, the grating layer having a first side and having a second side opposite the first side and comprising a contiguous core grating region having a grating structure, wherein an index...

  5. Oral cavity and jaw

    International Nuclear Information System (INIS)

    Solntsev, A.M.; Koval', G.Yu.

    1984-01-01

    Radioanatome of oral cavity and jaw is described. Diseases of the teeth, jaw, large salivary glands, temporo-mandibular articulation are considered. Roentgenograms of oral cacity and jaw of healthy people are presented and analyzed as well as roentgenograms in the above-mentioned diseases

  6. Niobium superconducting cavity

    CERN Multimedia

    CERN PhotoLab

    1980-01-01

    This 5-cell superconducting cavity, made from bulk-Nb, stems from the period of general studies, not all directed towards direct use at LEP. This one is dimensioned for 1.5 GHz, the frequency used at CEBAF and also studied at Saclay (LEP RF was 352.2 MHz). See also 7908227, 8007354, 8209255, 8210054, 8312339.

  7. Superconducting elliptical cavities

    CERN Document Server

    Sekutowicz, J K

    2011-01-01

    We give a brief overview of the history, state of the art, and future for elliptical superconducting cavities. Principles of the cell shape optimization, criteria for multi-cell structures design, HOM damping schemes and other features are discussed along with examples of superconducting structures for various applications.

  8. Additive Manufactured Superconducting Cavities

    Science.gov (United States)

    Holland, Eric; Rosen, Yaniv; Woolleet, Nathan; Materise, Nicholas; Voisin, Thomas; Wang, Morris; Mireles, Jorge; Carosi, Gianpaolo; Dubois, Jonathan

    Superconducting radio frequency cavities provide an ultra-low dissipative environment, which has enabled fundamental investigations in quantum mechanics, materials properties, and the search for new particles in and beyond the standard model. However, resonator designs are constrained by limitations in conventional machining techniques. For example, current through a seam is a limiting factor in performance for many waveguide cavities. Development of highly reproducible methods for metallic parts through additive manufacturing, referred to colloquially as 3D printing\\x9D, opens the possibility for novel cavity designs which cannot be implemented through conventional methods. We present preliminary investigations of superconducting cavities made through a selective laser melting process, which compacts a granular powder via a high-power laser according to a digitally defined geometry. Initial work suggests that assuming a loss model and numerically optimizing a geometry to minimize dissipation results in modest improvements in device performance. Furthermore, a subset of titanium alloys, particularly, a titanium, aluminum, vanadium alloy (Ti - 6Al - 4V) exhibits properties indicative of a high kinetic inductance material. This work is supported by LDRD 16-SI-004.

  9. Cavity Nesting Birds

    Science.gov (United States)

    Virgil E. Scott; Keith E. Evans; David R. Patton; Charles P. Stone

    1977-01-01

    Many species of cavity-nesting birds have declined because of habitat reduction. In the eastern United States, where primeval forests are gone, purple martins depend almost entirely on man-made nesting structures (Allen and Nice 1952). The hole-nesting population of peregrine falcons disappeared with the felling of the giant trees upon which they depended (Hickey and...

  10. LEP superconducting cavity

    CERN Multimedia

    1995-01-01

    Engineers work in a clean room on one of the superconducting cavities for the upgrade to the LEP accelerator, known as LEP-2. The use of superconductors allow higher electric fields to be produced so that higher beam energies can be reached.

  11. Open microwave cavities

    Czech Academy of Sciences Publication Activity Database

    Šeba, Petr; Rotter, I.; Mueller, M.; Persson, C.; Pichugin, Konstantin N.

    2001-01-01

    Roč. 9, - (2001), s. 484-487 ISSN 1386-9477 Institutional research plan: CEZ:A02/98:Z1-010-914 Keywords : microwave cavity * resonances Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.009, year: 2001

  12. Filling a Conical Cavity

    Science.gov (United States)

    Nye, Kyle; Eslam-Panah, Azar

    2016-11-01

    Root canal treatment involves the removal of infected tissue inside the tooth's canal system and filling the space with a dense sealing agent to prevent further infection. A good root canal treatment happens when the canals are filled homogeneously and tightly down to the root apex. Such a tooth is able to provide valuable service for an entire lifetime. However, there are some examples of poorly performed root canals where the anterior and posterior routes are not filled completely. Small packets of air can be trapped in narrow access cavities when restoring with resin composites. Such teeth can cause trouble even after many years and lead the conditions like acute bone infection or abscesses. In this study, the filling of dead-end conical cavities with various liquids is reported. The first case studies included conical cavity models with different angles and lengths to visualize the filling process. In this investigation, the rate and completeness at which a variety of liquids fill the cavity were observed to find ideal conditions for the process. Then, a 3D printed model of the scaled representation of a molar with prepared post spaces was used to simulate the root canal treatment. The results of this study can be used to gain a better understanding of the restoration for endodontically treated teeth.

  13. Implosion of the small cavity and large cavity cannonball targets

    International Nuclear Information System (INIS)

    Nishihara, Katsunobu; Yamanaka, Chiyoe.

    1984-01-01

    Recent results of cannonball target implosion research are briefly reviewed with theoretical predictions for GEKKO XII experiments. The cannonball targets are classified into two types according to the cavity size ; small cavity and large cavity. The compression mechanisms of the two types are discussed. (author)

  14. Diamagnetism of 2D-fermions in the strong nonhomogeneous static magnetic field B = B(0,0,1/cosh2(x-x0/δ))

    International Nuclear Information System (INIS)

    Hudak, O.

    1991-09-01

    We study diamagnetism of a gas of fermions moving in a nonhomogeneous magnetic field B = B(0,0,1/cosh 2 (x-x 0 /δ)). The gas magnetization, the static magnetic susceptibility, the chemical potential and the gas compressibility are discussed and compared with the uniform field case. (author). 5 refs

  15. Surgical Approaches to the Oral Cavity Primary and Neck

    International Nuclear Information System (INIS)

    Shah, Jatin P.

    2007-01-01

    Purpose: A variety of surgical approaches used to treat primary oral cavity tumors are described to delineate the technique and rationale behind each treatment choice. Methods and Materials: Size, location, proximity to bone, lymph node status, histology, and prior treatment considerations are employed to determine the most appropriate surgical approach for primary oral cavity tumors. Results: Oncologic outcomes and physical function show the best results from surgical treatment of many primary oral cavity, but necessitates careful selection of surgical approach. Conclusion: Each surgical approach must be selected based upon relevant tumor, patient and physician factors

  16. Hollow waveguide cavity ringdown spectroscopy

    Science.gov (United States)

    Dreyer, Chris (Inventor); Mungas, Greg S. (Inventor)

    2012-01-01

    Laser light is confined in a hollow waveguide between two highly reflective mirrors. This waveguide cavity is used to conduct Cavity Ringdown Absorption Spectroscopy of loss mechanisms in the cavity including absorption or scattering by gases, liquid, solids, and/or optical elements.

  17. Optimization of photonic crystal cavities

    DEFF Research Database (Denmark)

    Wang, Fengwen; Sigmund, Ole

    2017-01-01

    We present optimization of photonic crystal cavities. The optimization problem is formulated to maximize the Purcell factor of a photonic crystal cavity. Both topology optimization and air-hole-based shape optimization are utilized for the design process. Numerical results demonstrate...... that the Purcell factor of the photonic crystal cavity can be significantly improved through optimization....

  18. Nuclear reactor cavity streaming shield

    International Nuclear Information System (INIS)

    Klotz, R.J.; Stephen, D.W.

    1978-01-01

    The upper portion of a nuclear reactor vessel supported in a concrete reactor cavity has a structure mounted below the top of the vessel between the outer vessel wall and the reactor cavity wall which contains hydrogenous material which will attenuate radiation streaming upward between vessel and the reactor cavity wall while preventing pressure buildup during a loss of coolant accident

  19. Colloquium: cavity optomechanics

    CERN Multimedia

    2011-01-01

    Monday 14 November 2011, 17:00 Ecole de Physique, Auditoire Stueckelberg Université de Genève Cavity optomechanics: controlling micro mechanical oscillators with laser light Prof. Tobias Kippenberg EPFL, Lausanne Laser light can be used to cool and to control trapped ions, atoms and molecules at the quantum level. This has lead to spectacular advances such as the most precise atomic clocks. An outstanding frontier is the control with lasers of nano- and micro-mechancial systems. Recent advances in cavity optomechanics have allowed such elementary control for the first time, enabling mechanical systems to be ground state cooled leading to readout with quantum limited sensitivity and permitting to explore new device concepts resulting from radiation pressure.  

  20. Leaching materials from cavities

    International Nuclear Information System (INIS)

    Hodgson, T.D.; Jordan, T.W.J.

    1980-01-01

    A material is leached from a cavity by contacting the material with a liquid and subjecting the liquid to a number of pressure cycles, each pressure cycle involving a decrease in pressure to cause boiling of the liquid, followed by a rise in pressure to inhibit the boiling. The method may include the step of heating the liquid to a temperature near to its boiling point. The material may be nuclear fuel pellets or calcium carbonate pellets. (author)

  1. Superconducting cavities for HERA

    International Nuclear Information System (INIS)

    Dwersteg, B.; Ebeling, W.; Moeller, W.D.; Renken, D.; Proch, D.; Sekutowicz, J.; Susta, J.; Tong, D.

    1988-01-01

    Superconducting 500 MHz cavities are developed to demonstrate the feasibility of upgrading the e-beam energy of the HERA storage ring. A prototype module with 2 x 4 cell resonators and appropriate fundamental and higher mode couplers has been designed at DESY and is being built by industrial firms. The design and results of RF and cryogenic measurements are reported in detail. 17 references, 10 figures, 2 tables

  2. Crab cavities for linear colliders

    CERN Document Server

    Burt, G; Carter, R; Dexter, A; Tahir, I; Beard, C; Dykes, M; Goudket, P; Kalinin, A; Ma, L; McIntosh, P; Shulte, D; Jones, Roger M; Bellantoni, L; Chase, B; Church, M; Khabouline, T; Latina, A; Adolphsen, C; Li, Z; Seryi, Andrei; Xiao, L

    2008-01-01

    Crab cavities have been proposed for a wide number of accelerators and interest in crab cavities has recently increased after the successful operation of a pair of crab cavities in KEK-B. In particular crab cavities are required for both the ILC and CLIC linear colliders for bunch alignment. Consideration of bunch structure and size constraints favour a 3.9 GHz superconducting, multi-cell cavity as the solution for ILC, whilst bunch structure and beam-loading considerations suggest an X-band copper travelling wave structure for CLIC. These two cavity solutions are very different in design but share complex design issues. Phase stabilisation, beam loading, wakefields and mode damping are fundamental issues for these crab cavities. Requirements and potential design solutions will be discussed for both colliders.

  3. Signal attenuation due to cavity leakage

    International Nuclear Information System (INIS)

    Sherman, M.H.; Modera, M.P.

    1988-01-01

    The propagation of sound waves in fluids requires information about three properties of the system: capacitance (compressibility), resistance (friction), and inductance (inertia). Acoustical design techniques to date have tended to ignore the frictional effects associated with airflow across the envelope of the acoustic cavity (e.g., resistive vents). Since such leakage through the cavity envelope is best expressed with a power law dependence on the pressure, standard Fourier techniques that rely on linearity cannot be used. In this article, the theory relevant to nonlinear leakage is developed and equations presented. Potential applications of the theory to techniques for quantifying the leakage of buildings are presented. Experimental results from pressure decays in a full-scale test structure are presented and the leakage so measured is compared with independent measurements to demonstrate the technique

  4. ISR RF cavities

    CERN Multimedia

    1983-01-01

    In each ISR ring the radiofrequency cavities were installed in one 9 m long straight section. The RF system of the ISR had the main purpose to stack buckets of particles (most of the time protons)coming from the CPS and also to accelerate the stacked beam. The installed RF power per ring was 18 kW giving a peak accelerating voltage of 20 kV. The system had a very fine regulation feature allowing to lower the voltage down to 75 V in a smooth and well controlled fashion.

  5. Oral cavity eumycetoma

    Directory of Open Access Journals (Sweden)

    Gisele Alborghetti Nai

    2011-06-01

    Full Text Available Mycetoma is a pathological process in which eumycotic (fungal or actinomycotic causative agents from exogenous source produce grains. It is a localized chronic and deforming infectious disease of subcutaneous tissue, skin and bones. We report the first case of eumycetoma of the oral cavity in world literature. CASE REPORT: A 43-year-old male patient, complaining of swelling and fistula in the hard palate. On examination, swelling of the anterior and middle hard palate, with fistula draining a dark liquid was observed. The panoramic radiograph showed extensive radiolucent area involving the region of teeth 21-26 and the computerized tomography showed communication with the nasal cavity, suggesting the diagnosis of periapical cyst. Surgery was performed to remove the lesion. Histopathological examination revealed purulent material with characteristic grain. Gram staining for bacteria was negative and Grocott-Gomori staining for the detection of fungi was positive, concluding the diagnosis of eumycetoma. The patient was treated with ketoconazole for nine months, and was considered cured at the end of treatment. CONCLUSION: Histopathological examination, using histochemical staining, and direct microscopic grains examination can provide the distinction between eumycetoma and actinomycetoma accurately.

  6. Impurity states and the diamagnetic susceptibility of a donor in a GaAs/AlxGa1-xAs Triangular Quantum Well under hydrostatic pressure

    Science.gov (United States)

    Kalpana, Panneer Selvam; Jayakumar, Kalyanasundaram

    2017-11-01

    We study the effect of Γ-X band crossover due to the application of hydrostatic pressure of a hydrogenic donor confined in a Triangular GaAs/Al1-xGaxAs Quantum Well (TQW) for x = 0.3 and the diamagnetic susceptibility (χdia) for such an impurity in 1s and some few low lying excited states have been investigated. The Schrodinger equation has been solved using variational technique in the effective mass approximation. The results show that the diamagnetic susceptibility (χdia) of a hydrogenic donor abruptly increases at a particular pressure for 1s and 2p± states but a steady increase for 2s state as a function of applied pressure.

  7. Cryostat for TRISTAN superconducting cavity

    International Nuclear Information System (INIS)

    Mitsunobu, S.; Furuya, T.; Hara, K.

    1990-01-01

    Superconducting cavities generate rather high heat load of hundreds watts in one cryostat and have high sensitivity for pressure. We adopted usual pool-boiling type cooling for its stable pressure operation. Two 5-cell Nb cavities were installed in one flange type cryostat. Tuning mechanics actuated by a pulse-motor and a Piezo-electric element are set at outside of vacuum end flange. The design and performance of the cryostat for TRISTAN superconducting cavities are described. (author)

  8. Superconducting Radio-Frequency Cavities

    Science.gov (United States)

    Padamsee, Hasan S.

    2014-10-01

    Superconducting cavities have been operating routinely in a variety of accelerators with a range of demanding applications. With the success of completed projects, niobium cavities have become an enabling technology, offering upgrade paths for existing facilities and pushing frontier accelerators for nuclear physics, high-energy physics, materials science, and the life sciences. With continued progress in basic understanding of radio-frequency superconductivity, the performance of cavities has steadily improved to approach theoretical capabilities.

  9. Attempt to detect diamagnetic anisotropy of dust-sized crystal orientated to investigate the origin of interstellar dust alignment

    Science.gov (United States)

    Takeuchi, T.; Hisayoshi, K.; Uyeda, C.

    2013-03-01

    Diamagnetic anisotropy Δ χ dia was detected on a submillimeter-sized calcite crystal by observing the rotational oscillation of its magnetically stable axis with respect to the magnetic field direction. The crystal was released in an area of microgravity generated by a 1.5-m-long drop shaft. When the oscillations are observable, the present method can measure Δ χ dia of crystal grains irrespective of how small they are without measuring the sample mass. In conventional Δ χ measurements, the background signal from the sample holder and the difficulty in measuring the sample mass prevent measurement of Δ χ dia for small samples. The present technique of observing Δ χ dia of a submillimeter-sized single crystal is a step toward realizing Δ χ dia measurements of micron-sized grains. The Δ χ dia values of single micron-sized grains can be used to assess the validity of a dust alignment model based on magnetic torque that originates from the Δ χ dia of individual dust particles.

  10. Experimental study of pulsed heating of electromagnetic cavities

    International Nuclear Information System (INIS)

    Pritzkau, D.P.; Menegat, A.; Siemann, R.H.

    1997-01-01

    An experiment to study the effects of pulsed heating in electromagnetic cavities will be performed. Pulsed heating is believed to be the limiting mechanism of high acceleration gradients at short wavelengths. A cylindrical cavity operated in the TE 011 mode at a frequency of 11.424 GHz will be used. A klystron will be used to supply a peak input power of 20 MW with a pulse length of 1.5 μs. The temperature response of the cavity will be measured by a second waveguide designed to excite a TE 012 mode in the cavity with a low-power CW signal at a frequency of 17.8 GHz. The relevant theory of pulsed heating will be discussed and the results from cold-testing the structure will be presented

  11. CEBAF: Accelerating cavities look good

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1990-09-15

    The first assembled pairs of superconducting accelerating cavities from German supplier Interatom for the Continuous Electron Beam Accelerator Facility, Newport News, Virginia, have exceeded performance specifications.

  12. CEBAF: Accelerating cavities look good

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    The first assembled pairs of superconducting accelerating cavities from German supplier Interatom for the Continuous Electron Beam Accelerator Facility, Newport News, Virginia, have exceeded performance specifications

  13. Green's dyadic approach of the self-stress on a dielectric-diamagnetic cylinder with non-uniform speed of light

    International Nuclear Information System (INIS)

    Cavero-Pelaez, I; Milton, K A

    2006-01-01

    We present a Green's dyadic formulation to calculate the Casimir energy for a dielectric-diamagnetic cylinder with the speed of light differing inside and outside. Although the result is in general divergent, special cases are meaningful. It is pointed out how the self-stress on a purely dielectric cylinder vanishes through second order in the deviation of the permittivity from its vacuum value, in agreement with the result calculated from the sum of van der Waals forces

  14. Novel sensing and control schemes for a three-mirror coupled cavity

    International Nuclear Information System (INIS)

    Huttner, S H; Barr, B W; Plissi, M V; Taylor, J R; Sorazu, B; Strain, K A

    2007-01-01

    We present two options for length sensing and control of a three-mirror coupled cavity. The control of the first cavity uses amplitude or single sideband modulation and phase modulation in combination with a beat-frequency demodulation scheme, whereas the control scheme for the second cavity incorporates phase modulation and single demodulation. The theoretical and experimental performance is discussed as well as the relevance to a research programme to develop interferometric techniques for application in future interferometric gravitational wave detectors

  15. Single and Coupled Nanobeam Cavities

    DEFF Research Database (Denmark)

    Ivinskaya, Aliaksandra; Lavrinenko, Andrei; Shyroki, Dzmitry M.

    2013-01-01

    for analysis and design of photonic crystal devices, such as 2D ring resonators for filters, single and coupled nanobeam cavities, birefringence in photonic crystal cavities, threshold analysis in photonic crystal lasers, gap solitons in photonic crystals, novel photonic atolls, dynamic characteristics...

  16. Technical tasks in superconducting cavities

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Kenji [High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan)

    1997-11-01

    The feature of superconducting rf cavities is an extremely small surface resistance on the wall. It brings a large energy saving in the operation, even those are cooled with liquid helium. That also makes possible to operate themselves in a higher field gradient comparing to normal conducting cavities, and brings to make accelerators compact. These merits are very important for the future accelerator engineering which is planed at JAERI for the neutron material science and nuclear waste transmutation. This machine is a high intensity proton linac and uses sc cavities in the medium and high {beta} sections. In this paper, starting R and D of proton superconducting cavities, several important technical points which come from the small surface resistance of sc cavities, are present to succeed it and also differences between the medium and high - {beta} structures are discussed. (author)

  17. Pacer processing: cavity inventory relationships

    International Nuclear Information System (INIS)

    Dietz, R.J.; Gritzo, L.A.

    1975-09-01

    The pacer cavity and its associated primary power loop comprise a recirculating system in which materials are introduced by a series of thermonuclear explosions while debris is continuously removed by radioactive decay, sorption phenomena, and deliberate processing. Safe, reliable, and economical realization of the Pacer concept depends on the removal and control of both noxious and valuable by-products of the fusion reaction. Mathematical relationships are developed that describe the quantities of materials that are introduced into the Pacer cavity by a series of discrete events and are removed continuously by processing and decay. An iterative computer program based on these relationships is developed that allows both the total cavity inventory and the amounts of important individual species to be determined at any time during the lifetime of the cavity in order to establish the effects of the thermonuclear event, the cavity, the flow, and various processing parameters on Pacer design requirements

  18. Frequency-feedback cavity enhanced spectrometer

    Science.gov (United States)

    Hovde, David Christian; Gomez, Anthony

    2015-08-18

    A spectrometer comprising an optical cavity, a light source capable of producing light at one or more wavelengths transmitted by the cavity and with the light directed at the cavity, a detector and optics positioned to collect light transmitted by the cavity, feedback electronics causing oscillation of amplitude of the optical signal on the detector at a frequency that depends on cavity losses, and a sensor measuring the oscillation frequency to determine the cavity losses.

  19. Ligand Exchange Kinetics of Environmentally Relevant Metals

    Energy Technology Data Exchange (ETDEWEB)

    Panasci, Adele Frances [Univ. of California, Davis, CA (United States)

    2014-07-15

    The interactions of ground water with minerals and contaminants are of broad interest for geochemists but are not well understood. Experiments on the molecular scale can determine reaction parameters (i.e. rates of ligand exchange, activation entropy, activation entropy, and activation volume) that can be used in computations to gain insight into reactions that occur in natural groundwaters. Experiments to determine the rate of isotopic ligand exchange for three environmentally relevant metals, rhodium (Rh), iron (Fe), and neptunium (Np), are described. Many environmental transformations of metals (e.g. reduction) in soil occur at trivalent centers, Fe(III) in particular. Contaminant ions absorb to mineral surfaces via ligand exchange, and the reversal of this reaction can be dangerous, releasing contaminants into the environment. Ferric iron is difficult to study spectroscopically because most of its complexes are paramagnetic and are generally reactive toward ligand exchange; therefore, Rh(III), which is diamagnetic and less reactive, was used to study substitution reactions that are analogous to those that occur on mineral oxide surfaces. Studies on both Np(V) and Np(VI) are important in their own right, as 237Np is a radioactive transuranic element with a half-life of 2 million years.

  20. Nonlocal Intracranial Cavity Extraction

    Science.gov (United States)

    Manjón, José V.; Eskildsen, Simon F.; Coupé, Pierrick; Romero, José E.; Collins, D. Louis; Robles, Montserrat

    2014-01-01

    Automatic and accurate methods to estimate normalized regional brain volumes from MRI data are valuable tools which may help to obtain an objective diagnosis and followup of many neurological diseases. To estimate such regional brain volumes, the intracranial cavity volume (ICV) is often used for normalization. However, the high variability of brain shape and size due to normal intersubject variability, normal changes occurring over the lifespan, and abnormal changes due to disease makes the ICV estimation problem challenging. In this paper, we present a new approach to perform ICV extraction based on the use of a library of prelabeled brain images to capture the large variability of brain shapes. To this end, an improved nonlocal label fusion scheme based on BEaST technique is proposed to increase the accuracy of the ICV estimation. The proposed method is compared with recent state-of-the-art methods and the results demonstrate an improved performance both in terms of accuracy and reproducibility while maintaining a reduced computational burden. PMID:25328511

  1. Nonlocal Intracranial Cavity Extraction

    Directory of Open Access Journals (Sweden)

    José V. Manjón

    2014-01-01

    Full Text Available Automatic and accurate methods to estimate normalized regional brain volumes from MRI data are valuable tools which may help to obtain an objective diagnosis and followup of many neurological diseases. To estimate such regional brain volumes, the intracranial cavity volume (ICV is often used for normalization. However, the high variability of brain shape and size due to normal intersubject variability, normal changes occurring over the lifespan, and abnormal changes due to disease makes the ICV estimation problem challenging. In this paper, we present a new approach to perform ICV extraction based on the use of a library of prelabeled brain images to capture the large variability of brain shapes. To this end, an improved nonlocal label fusion scheme based on BEaST technique is proposed to increase the accuracy of the ICV estimation. The proposed method is compared with recent state-of-the-art methods and the results demonstrate an improved performance both in terms of accuracy and reproducibility while maintaining a reduced computational burden.

  2. Photons in a spherical cavity

    International Nuclear Information System (INIS)

    Ionescu-Pallas, N.; Vlad, V.I.

    1999-01-01

    The spectrum of black body radiation at the absolute temperature T, in an ideal spherical cavity of radius R, is studied. The departures from the classical predictions of Planck's theory, due to the discrete energies of the radiation quanta confined inside the cavity, depend on the adiabatic invariant RT and are significant for RT≤ 1 cm K. Special attention was paid to evidence sudden changes in the spectrum intensities, forbidden bands of frequency, as well as major modifications of the total energy for RT≤ 1 cm K. Similar effects were present in case of a cubic cavity too. (authors)

  3. Cavity and goaf control

    Energy Technology Data Exchange (ETDEWEB)

    Stassen, P

    1978-01-01

    A summary of stowing, including a definition, calculation of stowing material requirements and settling of packs is given. A) Stowing using dirt found locally - the dirt bands in the seam - the use of ripping dirt brought down by the scraper loader and used for packing purposes and the construction of dummy roads. B) Control of cavities by leaving short, thick props and timber chocks in place. C) Stowing methods involving imported firt: packing by hand, use of scraper loaders, slinger stowing and control led-gravity stowing. D) Pneumatic stowing: describes the various types of machine and their scope; pipelines, their installation and cost price; pneumatic stowing in conjunc tion with powered supports; the use of crusher-stowers for stowing ripping dirt; construction of anhydrite packs by means of a pneumatic stower. E) Hydraulic stowing: how it works, the materials involved, utilization conditions, the surface storage post, pipes, stoppings with stowed material, water removal, rates of hydraulic stowing, results of theoretical studies, and the use of hydraulic stowing in the metal-mines. F) Pumped packs: how they work, how the packs are installed, the strength of the packs and their various uses. G) Caving: describes the principle of caving, support patterns, caving with packs and makes a comparison between caving and stowing. H) Comparison between the various methods of stowing compares pneumatic with hydraulic stowing methods; compares packing by hand and mechanical stowing compares surface subsidence in terms of the method of goaf used underground. An appendix gives details of equipment used. (15 refs.) (In French)

  4. Loggerhead oral cavity morphometry study

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Standard external morphometrics and internal oral cavity morphometrics data were collected on wild and captive reared loggerhead sea turtles in size classes ranging...

  5. Niobium LEP 2 accelerating cavities

    CERN Multimedia

    An accelerating cavity from LEP. This could be cut open to show the layer of niobium on the inside. Operating at 4.2 degrees above absolute zero, the niobium is superconducting and carries an accelerating field of 6 million volts per metre with negligible losses. Each cavity has a surface of 6 m2. The niobium layer is only 1.2 microns thick, ten times thinner than a hair. Such a large area had never been coated to such a high accuracy. A speck of dust could ruin the performance of the whole cavity so the work had to be done in an extremely clean environment. These challenging requirements pushed European industry to new achievements. 256 of these cavities were used in an upgrade of the LEP accelerator to double the energy of the particle beams.

  6. Bistability of Cavity Magnon Polaritons

    Science.gov (United States)

    Wang, Yi-Pu; Zhang, Guo-Qiang; Zhang, Dengke; Li, Tie-Fu; Hu, C.-M.; You, J. Q.

    2018-01-01

    We report the first observation of the magnon-polariton bistability in a cavity magnonics system consisting of cavity photons strongly interacting with the magnons in a small yttrium iron garnet (YIG) sphere. The bistable behaviors emerged as sharp frequency switchings of the cavity magnon polaritons (CMPs) and related to the transition between states with large and small numbers of polaritons. In our experiment, we align, respectively, the [100] and [110] crystallographic axes of the YIG sphere parallel to the static magnetic field and find very different bistable behaviors (e.g., clockwise and counter-clockwise hysteresis loops) in these two cases. The experimental results are well fitted and explained as being due to the Kerr nonlinearity with either a positive or negative coefficient. Moreover, when the magnetic field is tuned away from the anticrossing point of CMPs, we observe simultaneous bistability of both magnons and cavity photons by applying a drive field on the lower branch.

  7. Design of rf conditioner cavities

    International Nuclear Information System (INIS)

    Govil, R.; Rimmer, R.A.; Sessler, A.; Kirk, H.G.

    1992-06-01

    Theoretical studies are made of radio frequency structures which can be used to condition electron beams so as to greatly reduce the stringent emittance requirements for successful lasing in a free-electron laser. The basic strategy of conditioning calls for modulating an electron beam in the transverse dimension, by a periodic focusing channel, while it traverses a series of rf cavities, each operating in a TM 210 mode. In this paper, we analyze the cavities both analytically and numerically (using MAFIA simulations). We find that when cylindrical symmetry is broken the coupling impedance can be greatly enhanced. We present results showing various performance characteristics as a function of cavity parameters, as well as possible designs for conditioning cavities

  8. SRF Cavity Fabrication and Materials

    CERN Document Server

    Singer, W

    2014-07-17

    The technological and metallurgical requirements of material for highgradient superconducting cavities are described. High-purity niobium, as the preferred metal for the fabrication of superconducting accelerating cavities, should meet exact specifications. The content of interstitial impurities such as oxygen, nitrogen, and carbon must be below 10μg/g. The hydrogen content should be kept below 2μg/g to prevent degradation of the Q-value under certain cool-down conditions. The material should be free of flaws (foreign material inclusions or cracks and laminations) that can initiate a thermal breakdown. Defects may be detected by quality control methods such as eddy current scanning and identified by a number of special methods. Conventional and alternative cavity fabrication methods are reviewed. Conventionally, niobium cavities are fabricated from sheet niobium by the formation of half-cells by deep drawing, followed by trim machining and Electron-Beam Welding (EBW). The welding of half-cells is a delicate...

  9. LEP Radio Frequency Copper Cavity

    CERN Multimedia

    The pulse of a particle accelerator. 128 of these radio frequency cavities were positioned around CERN's 27-kilometre LEP ring to accelerate electrons and positrons. The acceleration was produced by microwave electric oscillations at 352 MHz. The electrons and positrons were grouped into bunches, like beads on a string, and the copper sphere at the top stored the microwave energy between the passage of individual bunches. This made for valuable energy savings as it reduced the heat generated in the cavity.

  10. TESLA superconducting RF cavity development

    International Nuclear Information System (INIS)

    Koepke, K.

    1995-01-01

    The TESLA collaboration has made steady progress since its first official meeting at Cornell in 1990. The infrastructure necessary to assemble and test superconducting rf cavities has been installed at the TESLA Test Facility (TTF) at DESY. 5-cell, 1.3 GHz cavities have been fabricated and have reached accelerating fields of 25 MV/m. Full sized 9-cell copper cavities of TESLA geometry have been measured to verify the higher order modes present and to evaluate HOM coupling designs. The design of the TESLA 9-cell cavity has been finalized and industry has started delivery. Two prototype 9-cell niobium cavities in their first tests have reached accelerating fields of 10 MV/m and 15 MV/m in a vertical dewar after high peak power (HPP) conditioning. The first 12 m TESLA cryomodule that will house 8 9-cell cavities is scheduled to be delivered in Spring 1995. A design report for the TTF is in progress. The TTF test linac is scheduled to be commissioned in 1996/1997. (orig.)

  11. 21 CFR 872.3260 - Cavity varnish.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cavity varnish. 872.3260 Section 872.3260 Food and... DENTAL DEVICES Prosthetic Devices § 872.3260 Cavity varnish. (a) Identification. Cavity varnish is a device that consists of a compound intended to coat a prepared cavity of a tooth before insertion of...

  12. TEM observations of crack tip: cavity interactions

    International Nuclear Information System (INIS)

    Horton, J.A.; Ohr, S.M.; Jesser, W.A.

    1981-01-01

    Crack tip-cavity interactions have been studied by performing room temperature deformation experiments in a transmission electron microscope on ion-irradiated type 316 stainless steel with small helium containing cavities. Slip dislocations emitted from a crack tip cut, sheared, and thereby elongated cavities without a volume enlargement. As the crack tip approached, a cavity volume enlargement occurred. Instead of the cavities continuing to enlarge until they touch, the walls between the cavities fractured. Fracture surface dimples do not correlate in size or density with these enlarged cavities

  13. Fabrication of elliptical SRF cavities

    Science.gov (United States)

    Singer, W.

    2017-03-01

    The technological and metallurgical requirements of material for high-gradient superconducting cavities are described. High-purity niobium, as the preferred metal for the fabrication of superconducting accelerating cavities, should meet exact specifications. The content of interstitial impurities such as oxygen, nitrogen, and carbon must be below 10 μg g-1. The hydrogen content should be kept below 2 μg g-1 to prevent degradation of the quality factor (Q-value) under certain cool-down conditions. The material should be free of flaws (foreign material inclusions or cracks and laminations) that can initiate a thermal breakdown. Traditional and alternative cavity mechanical fabrication methods are reviewed. Conventionally, niobium cavities are fabricated from sheet niobium by the formation of half-cells by deep drawing, followed by trim machining and electron beam welding. The welding of half-cells is a delicate procedure, requiring intermediate cleaning steps and a careful choice of weld parameters to achieve full penetration of the joints. A challenge for a welded construction is the tight mechanical and electrical tolerances. These can be maintained by a combination of mechanical and radio-frequency measurements on half-cells and by careful tracking of weld shrinkage. The main aspects of quality assurance and quality management are mentioned. The experiences of 800 cavities produced for the European XFEL are presented. Another cavity fabrication approach is slicing discs from the ingot and producing cavities by deep drawing and electron beam welding. Accelerating gradients at the level of 35-45 MV m-1 can be achieved by applying electrochemical polishing treatment. The single-crystal option (grain boundary free) is discussed. It seems that in this case, high performance can be achieved by a simplified treatment procedure. Fabrication of the elliptical resonators from a seamless pipe as an alternative is briefly described. This technology has yielded good

  14. Hydroforming of superconducting TESLA cavities

    International Nuclear Information System (INIS)

    Singer, W.; Kaiser, H.; Singer, X.

    2003-01-01

    Seamless fabrication of single-cell and multi-cell TESLA shape cavities by hydroforming has been developed at DESY. The forming takes place by expanding the seamless tube with internal water pressure while simultaneously swaging it axially. Tube radius and axial displacement are being computer controlled in accordance with results of FEM simulations and the experimentally obtained strain-stress curve of tube material. Several Nb single cell cavities have been produced. A first bulk Nb double cell cavity has been fabricated. The Nb seamless tubes have been produced by spinning and deep drawing. Surface treatment such as buffered chemical polishing, (BCP), electropolishing (EP), high pressure ultra pure water rinsing (HPR), annealing at 800degC and baking at ca. 150degC have been applied. The best single cell bulk Nb cavity has reached an accelerating gradient of Eacc > 42 MV/m after ca. 250 μm BCP and 100 μm EP. Several bimetallic NbCu single cell cavities of TESLA shape have been fabricated. The seamless tubes have been produced by explosive bonding and subsequent flow forming. The thicknesses of Nb and Cu layers in the tube wall are about 1 mm and 3 mm respectively. The RF performance of NbCu clad cavities is similar to that of bulk Nb cavities. The highest accelerating gradient achieved was 40 MV/m after ca. 180 μm BCP, annealing at 800degC and baking at 140degC for 30 hours. The degradation of the quality factor Qo after repeated quenching is moderate, after ca. 150 quenches it reaches the saturation point of Qo=1.4x10 10 at low field. This indicates that on the basis of RF performance and material costs the combination of hydroforming with tube cladding is a very promising option. (author)

  15. Partial Cavity Flows at High Reynolds Numbers

    Science.gov (United States)

    Makiharju, Simo; Elbing, Brian; Wiggins, Andrew; Dowling, David; Perlin, Marc; Ceccio, Steven

    2009-11-01

    Partial cavity flows created for friction drag reduction were examined on a large-scale. Partial cavities were investigated at Reynolds numbers up to 120 million, and stable cavities with frictional drag reduction of more than 95% were attained at optimal conditions. The model used was a 3 m wide and 12 m long flat plate with a plenum on the bottom. To create the partial cavity, air was injected at the base of an 18 cm backwards-facing step 2.1 m from the leading edge. The geometry at the cavity closure was varied for different flow speeds to optimize the closure of the cavity. Cavity gas flux, thickness, frictional loads, and cavity pressures were measured over a range of flow speeds and air injection fluxes. High-speed video was used extensively to investigate the unsteady three dimensional cavity closure, the overall cavity shape and oscillations.

  16. Normal Conducting RF Cavity for MICE

    International Nuclear Information System (INIS)

    Li, D.; DeMello, A.; Virostek, S.; Zisman, M.; Summers, D.

    2010-01-01

    Normal conducting RF cavities must be used for the cooling section of the international Muon Ionization Cooling Experiment (MICE), currently under construction at Rutherford Appleton Laboratory (RAL) in the UK. Eight 201-MHz cavities are needed for the MICE cooling section; fabrication of the first five cavities is complete. We report the cavity fabrication status including cavity design, fabrication techniques and preliminary low power RF measurements.

  17. Why relevance theory is relevant for lexicography

    DEFF Research Database (Denmark)

    Bothma, Theo; Tarp, Sven

    2014-01-01

    This article starts by providing a brief summary of relevance theory in information science in relation to the function theory of lexicography, explaining the different types of relevance, viz. objective system relevance and the subjective types of relevance, i.e. topical, cognitive, situational...... that is very important for lexicography as well as for information science, viz. functional relevance. Since all lexicographic work is ultimately aimed at satisfying users’ information needs, the article then discusses why the lexicographer should take note of all these types of relevance when planning a new...... dictionary project, identifying new tasks and responsibilities of the modern lexicographer. The article furthermore discusses how relevance theory impacts on teaching dictionary culture and reference skills. By integrating insights from lexicography and information science, the article contributes to new...

  18. Thermal conditions within tree cavities in ponderosa pine (Pinus ponderosa) forests: potential implications for cavity users

    Science.gov (United States)

    Vierling, Kerri T.; Lorenz, Teresa J.; Cunningham, Patrick; Potterf, Kelsi

    2017-11-01

    Tree cavities provide critical roosting and breeding sites for multiple species, and thermal environments in these cavities are important to understand. Our objectives were to (1) describe thermal characteristics in cavities between June 3 and August 9, 2014, and (2) investigate the environmental factors that influence cavity temperatures. We placed iButtons in 84 different cavities in ponderosa pine (Pinus ponderosa) forests in central Washington, and took hourly measurements for at least 8 days in each cavity. Temperatures above 40 °C are generally lethal to developing avian embryos, and 18% of the cavities had internal temperatures of ≥ 40 °C for at least 1 h of each day. We modeled daily maximum cavity temperature, the amplitude of daily cavity temperatures, and the difference between the mean internal cavity and mean ambient temperatures as a function of several environmental variables. These variables included canopy cover, tree diameter at cavity height, cavity volume, entrance area, the hardness of the cavity body, the hardness of the cavity sill (which is the wood below the cavity entrance which forms the barrier between the cavity and the external environment), and sill width. Ambient temperature had the largest effect size for maximum cavity temperature and amplitude. Larger trees with harder sills may provide more thermally stable cavity environments, and decayed sills were positively associated with maximum cavity temperatures. Summer temperatures are projected to increase in this region, and additional research is needed to determine how the thermal environments of cavities will influence species occupancy, breeding, and survival.

  19. Red-cockaded woodpecker nest-cavity selection: relationships with cavity age and resin production

    Science.gov (United States)

    Richard N. Conner; Daniel Saenz; D. Craig Rudolph; William G. Ross; David L. Kulhavy

    1998-01-01

    The authors evaluated selection of nest sites by male red-cockaded woodpeckers (Picoides borealis) in Texas relative to the age of the cavity when only cavities excavated by the woodpeckers were available and when both naturally excavated cavities and artificial cavities were available. They also evaluated nest-cavity selection relative to the ability of naturally...

  20. CEBAF's SRF cavity manufacturing experience

    International Nuclear Information System (INIS)

    Benesch, J.F.; Reece, C.E.

    1994-01-01

    Construction of the Continuous Electron Beam Accelerator Facility (CEBAF) recirculating linac represents the largest scale application of superconducting rf (SRF) technology to date. The accelerating structures in CEBAF are 169 pairs of 1.5 GHz superconducting rf cavities -- 9 pairs in an injector and 80 pairs each in two linacs. The beam is to be recirculated up to five passes through each linac. Data is presented on mechanical tolerances achieved by the industrial fabricator of the rf cavities (Siemens). Liquid helium leak rates integrated over 22 vacuum seals have been measured on over 110 cavity pairs. A roughly normal distribution of the log 10 (leak rate) is seen, centered about a rate of 10 -10.4 torr-l/s. Over 140 pairs of the cavities have been assembled and have completed rf testing at 2.0 K. Among these, 54% demonstrated usable accelerating gradients greater than 10 MV/m. Although the rf performance characteristics well exceed the CEBAF baseline requirements of 5 MV/m at Q 0 = 2.4x10 9 , the usual limiting phenomena are encountered: field emission, quenching, and occasional multipacting. A discussion of the occurrence conditions and severity of these phenomena during production cavity testing is presented. The frequency with which performance is limited by quenching suggests that additional material advances may be required for applications which require the reliable achievement of accelerating gradients of more than 15 MV/m

  1. Coupling of an overdriven cavity

    International Nuclear Information System (INIS)

    Garbin, H.D.

    1993-01-01

    It is well known that when a nuclear test is conducted in a sufficiently large cavity, the resulting seismic signal is sharply reduced when compared to a normal tamped event. Cavity explosions are of interest in the seismic verification community because of this possibility of reducing the seismic energy generated which can lower signal amplitudes and make detection difficult. Reduced amplitudes would also lower seismic yield estimates which has implications in a Threshold Test Ban Treaty (TTBT). In the past several years, there have been a number of nuclear tests at NTS (Nevada Test Site) inside hemispherical cavities. Two such tests were MILL YARD and MISTY ECHO which had instrumentation at the surface and in the free-field. These two tests differ in one important aspect. MILL YARD was completely decoupled i.e., the cavity wall behaved in an elastic manner. It was estimated that MILL YARD's ground motion was reduced by a factor of at least 70. In contrast, MISTY ECHO was detonated in a hemispherical cavity with the same dimensions as MILL YARD, but with a much larger device yield. This caused an inelastic behavior on the wall and the explosion was not fully decoupled

  2. Development of Side Coupled Cavities

    International Nuclear Information System (INIS)

    Conto, J.M. de; Carretta, J.M.; Gomez-Martinez, Y.; Micoud, R.

    2008-01-01

    Side coupled Cavities are good candidates for proton accelerations in the 90-180 MeV range, as it has been first proposed for the CERN LINAC4 project. A side coupled Linac is made of a lump chain of resonant cavities, alternatively accelerating and coupling. A side coupled cavity has been designed in a CERN-LPSC collaboration to achieve LINAC4 requirements. After RF studies, a complete thermal study has been done, showing that 10-15% is the absolute maximum duty-cycle achievable by such a cavity. Error studies have been developed. They have shown that a tuning ring is mandatory and that a K equals 3% coupling factor is a good choice. A prototype has been built and each cell has been measured and tuned. A simple and accurate method has been used to get both the resonant frequency and the coupling factor, with a movable tuner and a linear fit. A similar method has been used to get the second order coupling factor. A large dispersion is observed on K. This is mainly due to the shape of the coupling apertures, which are very sensitive to mechanical errors. A future and realistic design must be very careful to guarantee a constant aperture (the important parameter is more the dispersion of k than its exact value). Finally, we analyse how to tune the cavity. This has to checked carefully and probably improved or corrected. Results are expected for mid-2008

  3. Noise-driven diamagnetic susceptibility of impurity doped quantum dots: Role of anisotropy, position-dependent effective mass and position-dependent dielectric screening function

    International Nuclear Information System (INIS)

    Bera, Aindrila; Saha, Surajit; Ganguly, Jayanta; Ghosh, Manas

    2016-01-01

    Highlights: • Diamagnetic susceptibility (DMS) of doped quantum dot is studied. • The dot is subjected to Gaussian white noise. • Role of anisotropy, PDEM and PDDSF have been analyzed. • Noise amplifies and suppresses DMS depending on particular condition. • Findings bear significant technological importance. - Abstract: We explore Diamagnetic susceptibility (DMS) of impurity doped quantum dot (QD) in presence of Gaussian white noise introduced to the system additively and multiplicatively. In view of this profiles of DMS have been pursued with variations of geometrical anisotropy and dopant location. We have invoked position-dependent effective mass (PDEM) and position-dependent dielectric screening function (PDDSF) of the system. Presence of noise sometimes suppresses and sometimes amplifies DMS from that of noise-free condition and the extent of suppression/amplification depends on mode of application of noise. It is important to mention that the said suppression/amplification exhibits subtle dependence on use of PDEM, PDDSF and geometrical anisotropy. The study reveals that DMS, or more fundamentally, the effective confinement of LDSS, can be tuned by appropriate mingling of geometrical anisotropy/effective mass/dielectric constant of the system with noise and also on the pathway of application of latter.

  4. A SURVEY OF CORONAL CAVITY DENSITY PROFILES

    International Nuclear Information System (INIS)

    Fuller, J.; Gibson, S. E.

    2009-01-01

    Coronal cavities are common features of the solar corona that appear as darkened regions at the base of coronal helmet streamers in coronagraph images. Their darkened appearance indicates that they are regions of lowered density embedded within the comparatively higher density helmet streamer. Despite interfering projection effects of the surrounding helmet streamer (which we refer to as the cavity rim), Fuller et al. have shown that under certain conditions it is possible to use a Van de Hulst inversion of white-light polarized brightness (pB) data to calculate the electron density of both the cavity and cavity rim plasma. In this article, we apply minor modifications to the methods of Fuller et al. in order to improve the accuracy and versatility of the inversion process, and use the new methods to calculate density profiles for both the cavity and cavity rim in 24 cavity systems. We also examine trends in cavity morphology and how departures from the model geometry affect our density calculations. The density calculations reveal that in all 24 cases the cavity plasma has a flatter density profile than the plasma of the cavity rim, meaning that the cavity has a larger density depletion at low altitudes than it does at high altitudes. We find that the mean cavity density is over four times greater than that of a coronal hole at an altitude of 1.2 R sun and that every cavity in the sample is over twice as dense as a coronal hole at this altitude. Furthermore, we find that different cavity systems near solar maximum span a greater range in density at 1.2 R sun than do cavity systems near solar minimum, with a slight trend toward higher densities for systems nearer to solar maximum. Finally, we found no significant correlation of cavity density properties with cavity height-indeed, cavities show remarkably similar density depletions-except for the two smallest cavities that show significantly greater depletion.

  5. Review of cavity optomechanical cooling

    International Nuclear Information System (INIS)

    Liu Yong-Chun; Hu Yu-Wen; Xiao Yun-Feng; Wong Chee Wei

    2013-01-01

    Quantum manipulation of macroscopic mechanical systems is of great interest in both fundamental physics and applications ranging from high-precision metrology to quantum information processing. For these purposes, a crucial step is to cool the mechanical system to its quantum ground state. In this review, we focus on the cavity optomechanical cooling, which exploits the cavity enhanced interaction between optical field and mechanical motion to reduce the thermal noise. Recent remarkable theoretical and experimental efforts in this field have taken a major step forward in preparing the motional quantum ground state of mesoscopic mechanical systems. This review first describes the quantum theory of cavity optomechanical cooling, including quantum noise approach and covariance approach; then, the up-to-date experimental progresses are introduced. Finally, new cooling approaches are discussed along the directions of cooling in the strong coupling regime and cooling beyond the resolved sideband limit. (topical review - quantum information)

  6. On niobium sputter coated cavities

    International Nuclear Information System (INIS)

    Arnolds-Mayer, G.; Kaufmann, U.; Downar, H.

    1988-01-01

    To coat copper cavities with a thin film of niobium, facilities for electropolishing and sputter deposition have been installed at Dornier. Experiments have been performed on samples to optimize electropolishing and deposition parameters. In this paper, characteristics concerning surface properties, adhesion of the niobium film to the copper substrate, and film properties were studied on planar samples. A 1.5 GHz single cell cavity made from oxygen free high conductivity (OFHC) copper was sputter coated twice. First rf measurements were performed in the temperature range from 300 K to 2 K

  7. Deep learning relevance

    DEFF Research Database (Denmark)

    Lioma, Christina; Larsen, Birger; Petersen, Casper

    2016-01-01

    train a Recurrent Neural Network (RNN) on existing relevant information to that query. We then use the RNN to "deep learn" a single, synthetic, and we assume, relevant document for that query. We design a crowdsourcing experiment to assess how relevant the "deep learned" document is, compared...... to existing relevant documents. Users are shown a query and four wordclouds (of three existing relevant documents and our deep learned synthetic document). The synthetic document is ranked on average most relevant of all....

  8. Conduction cooling systems for linear accelerator cavities

    Science.gov (United States)

    Kephart, Robert

    2017-05-02

    A conduction cooling system for linear accelerator cavities. The system conducts heat from the cavities to a refrigeration unit using at least one cavity cooler interconnected with a cooling connector. The cavity cooler and cooling connector are both made from solid material having a very high thermal conductivity of approximately 1.times.10.sup.4 W m.sup.-1 K.sup.-1 at temperatures of approximately 4 degrees K. This allows for very simple and effective conduction of waste heat from the linear accelerator cavities to the cavity cooler, along the cooling connector, and thence to the refrigeration unit.

  9. Simulation of plasma loading of high-pressure RF cavities

    Science.gov (United States)

    Yu, K.; Samulyak, R.; Yonehara, K.; Freemire, B.

    2018-01-01

    Muon beam-induced plasma loading of radio-frequency (RF) cavities filled with high pressure hydrogen gas with 1% dry air dopant has been studied via numerical simulations. The electromagnetic code SPACE, that resolves relevant atomic physics processes, including ionization by the muon beam, electron attachment to dopant molecules, and electron-ion and ion-ion recombination, has been used. Simulations studies have been performed in the range of parameters typical for practical muon cooling channels.

  10. Simulation of plasma loading of high-pressure RF cavities

    Energy Technology Data Exchange (ETDEWEB)

    Yu, K. [Brookhaven National Lab. (BNL), Upton, NY (United States). Computational Science Initiative; Samulyak, R. [Brookhaven National Lab. (BNL), Upton, NY (United States). Computational Science Initiative; Stony Brook Univ., NY (United States). Dept. of Applied Mathematics and Statistics; Yonehara, K. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Freemire, B. [Northern Illinois Univ., DeKalb, IL (United States)

    2018-01-11

    Muon beam-induced plasma loading of radio-frequency (RF) cavities filled with high pressure hydrogen gas with 1% dry air dopant has been studied via numerical simulations. The electromagnetic code SPACE, that resolves relevant atomic physics processes, including ionization by the muon beam, electron attachment to dopant molecules, and electron-ion and ion-ion recombination, has been used. Simulations studies have also been performed in the range of parameters typical for practical muon cooling channels.

  11. Sterility of the uterine cavity

    DEFF Research Database (Denmark)

    Møller, Birger R.; Kristiansen, Frank V.; Thorsen, Poul

    1995-01-01

    from the same sites. Nearly a quarter of all the patients harbored one or more microorganisms in the uterus, mostly Gardnerella vaginalis, Enterobacter and Streptococcus agalactiae. We found that in a significant number of cases, the uterine cavity is colonized with potentially pathogenic organisms...

  12. Flux trapping in superconducting cavities

    International Nuclear Information System (INIS)

    Vallet, C.; Bolore, M.; Bonin, B.; Charrier, J.P.; Daillant, B.; Gratadour, J.; Koechlin, F.; Safa, H.

    1992-01-01

    The flux trapped in various field cooled Nb and Pb samples has been measured. For ambient fields smaller than 3 Gauss, 100% of the flux is trapped. The consequences of this result on the behavior of superconducting RF cavities are discussed. (author) 12 refs.; 2 figs

  13. Field emission in RF cavities

    International Nuclear Information System (INIS)

    Bonin, B.

    1996-01-01

    Electron field emission limits the accelerating gradient in superconducting cavities. It is shown how and why it is an important problem. The phenomenology of field emission is then described, both in DC and RF regimes. Merits of a few plausible 'remedies' to field emission are discussed. (author)

  14. Superconducting cavity development at RRCAT

    International Nuclear Information System (INIS)

    Joshi, S.C.

    2015-01-01

    Raja Ramanna Centre for Advanced Technology (RRCAT), Indore pursuing a program on 'R and D Activities for High Energy Proton Linac based Spallation Neutron Source'. Spallation neutron source (SNS) facility will provide high flux pulse neutrons for research in the areas of condensed matter physics, materials science, chemistry, biology and engineering. This will complement the existing synchrotron light source facility, INDUS-2 at RRCAT and reactor based neutron facilities at BARC. RRCAT is also participating in approved mega project on 'Physics and Advanced Technology for High Intensity Proton Accelerator' to support activities of Indian Institutions - Fermilab Collaboration (IIFC). The SNS facility will have a 1 GeV superconducting proton injector linac and 1 GeV accumulator ring. The linac will comprise of large number of superconducting radio-frequency (SCRF) cavities operating at different RF frequencies housed in suitable cryomodules. Thus, an extensive SCRF cavity infrastructure setup is being established. In addition, a scientific and technical expertise are also being developed for fabrication, processing and testing of the SCRF cavities for series production. The paper presents the status of superconducting cavity development at RRCAT

  15. Thoracic cavity after thoracic operations

    International Nuclear Information System (INIS)

    Rabkin, I.Kh.

    1983-01-01

    The problems of roentgenologic method application to detect postoperative c omplications in pulmonary tissue, bronchi, pleural cavity, mediastinum, have been considered. It is shown, that the use of the above mentioned method permit s to judge on the rates and degrees of the lungs straightening, anatomic structures shift, the change in air- and blood-filling, accumulation of liquid a nd air in pleuritic

  16. "Grinding" cavities in polyurethane foam

    Science.gov (United States)

    Brower, J. R.; Davey, R. E.; Dixon, W. F.; Robb, P. H.; Zebus, P. P.

    1980-01-01

    Grinding tool installed on conventional milling machine cuts precise cavities in foam blocks. Method is well suited for prototype or midsize production runs and can be adapted to computer control for mass production. Method saves time and materials compared to bonding or hot wire techniques.

  17. Droplet based cavities and lasers

    DEFF Research Database (Denmark)

    Mølhave, Kristian; Kristensen, Anders; Mortensen, Asger

    2009-01-01

    The self-organized and molecularly smooth surface on liquid microdroplets makes them attractive as optical cavities with very high quality factors. This chapter describes the basic theory of optical modes in spherical droplets. The mechanical properties including vibrational excitation are also d...

  18. Superconducting cavities for beauty factories

    International Nuclear Information System (INIS)

    Lengeler, H.

    1992-01-01

    The possibilities and merits of superconducting accelerating cavities for Beauty-factories are considered. There exist already large sc systems of size and frequency comparable to the ones needed for Beauty-factories. Their status and operation experience is discussed. A comparison of normal conducting and superconducting systems is done for two typical Beauty-factory rings

  19. SRF Cavity Fabrication and Materials

    Energy Technology Data Exchange (ETDEWEB)

    Singer, W [DESY (Germany)

    2014-07-01

    The technological and metallurgical requirements of material for highgradient superconducting cavities are described. High-purity niobium, as the preferred metal for the fabrication of superconducting accelerating cavities, should meet exact specifications. The content of interstitial impurities such as oxygen, nitrogen, and carbon must be below 10μg/g. The hydrogen content should be kept below 2μg/g to prevent degradation of the Q-value under certain cool-down conditions. The material should be free of flaws (foreign material inclusions or cracks and laminations) that can initiate a thermal breakdown. Defects may be detected by quality control methods such as eddy current scanning and identified by a number of special methods. Conventional and alternative cavity fabrication methods are reviewed. Conventionally, niobium cavities are fabricated from sheet niobium by the formation of half-cells by deep drawing, followed by trim machining and Electron-Beam Welding (EBW). The welding of half-cells is a delicate procedure, requiring intermediate cleaning steps and a careful choice of weld parameters to achieve full penetration of the joints. The equator welds are particularly critical. A challenge for a welded construction is the tight mechanical and electrical tolerances. These can be maintained by a combination of mechanical and radio-frequency measurements on halfcells and by careful tracking of weld shrinkage. The established procedure is suitable for large series production. The main aspects of quality assurance management are mentioned. Another cavity fabrication approach is slicing discs from the ingot and producing cavities by deep drawing and EBW. Accelerating gradients at the level of 35–45 MV·m–1 can be achieved by applying Electropolishing (EP) treatment. Furthermore, the single-crystal option (grain boundary free) is promising. It seems that in this case, high performance can be achieved by a simplified treatment procedure. Fabrication of the

  20. Tuner Design for PEFP Superconducting RF Cavities

    International Nuclear Information System (INIS)

    Tang, Yazhe; An, Sun; Zhang, Liping; Cho, Yong Sub

    2009-01-01

    A superconducting radio frequency (SRF) cavity will be used to accelerate a proton beam after 100 MeV at 700 MHz in a linac of the Proton Engineering Frontier Project (PEFP) and its extended project. In order to control the SRF cavity's operating frequency at a low temperature, a new tuner has been developed for the PEFP SRF cavities. Each PEFP superconducting RF cavity has one tuner to match the cavity resonance frequency with the desired accelerator operating frequency; or to detune a cavity frequency a few bandwidths away from a resonance, so that the beam will not excite the fundamental mode, when the cavity is not being used for an acceleration. The PEFP cavity tuning is achieved by varying the total length of the cavity. The length of the cavity is controlled differentially by tuner acting with respect to the cavity body. The PEFP tuner is attached to the helium vessel and drives the cavity Field Probe (FP) side to change the frequency of the cavity

  1. Waveguide based external cavity semiconductor lasers

    NARCIS (Netherlands)

    Oldenbeuving, Ruud; Klein, E.J.; Offerhaus, Herman L.; Lee, Christopher James; Verhaegen, M.; Boller, Klaus J.

    2012-01-01

    We report on progress of the project waveguide based external cavity semiconductor laser (WECSL) arrays. Here we present the latest results on our efforts to mode lock an array of tunable, external cavity semiconductor lasers.

  2. Optical cavity furnace for semiconductor wafer processing

    Science.gov (United States)

    Sopori, Bhushan L.

    2014-08-05

    An optical cavity furnace 10 having multiple optical energy sources 12 associated with an optical cavity 18 of the furnace. The multiple optical energy sources 12 may be lamps or other devices suitable for producing an appropriate level of optical energy. The optical cavity furnace 10 may also include one or more reflectors 14 and one or more walls 16 associated with the optical energy sources 12 such that the reflectors 14 and walls 16 define the optical cavity 18. The walls 16 may have any desired configuration or shape to enhance operation of the furnace as an optical cavity 18. The optical energy sources 12 may be positioned at any location with respect to the reflectors 14 and walls defining the optical cavity. The optical cavity furnace 10 may further include a semiconductor wafer transport system 22 for transporting one or more semiconductor wafers 20 through the optical cavity.

  3. Cavity QED experiments with ion Coulomb crystals

    DEFF Research Database (Denmark)

    Herskind, Peter Fønss; Dantan, Aurélien; Marler, Joan

    2009-01-01

    Cavity QED experimental results demonstrating collective strong coupling between ensembles of atomic ions cooled into Coulomb crystals and optical cavity fields have been achieved. Collective Zeeman coherence times of milliseconds have furthermore been obtained.......Cavity QED experimental results demonstrating collective strong coupling between ensembles of atomic ions cooled into Coulomb crystals and optical cavity fields have been achieved. Collective Zeeman coherence times of milliseconds have furthermore been obtained....

  4. An economical wireless cavity-nest viewer

    Science.gov (United States)

    Daniel P. Huebner; Sarah R. Hurteau

    2007-01-01

    Inspection of cavity nests and nest boxes is often required during studies of cavity-nesting birds, and fiberscopes and pole-mounted video cameras are sometimes used for such inspection. However, the cost of these systems may be prohibitive for some potential users. We describe a user-built, wireless cavity viewer that can be used to access cavities as high as 15 m and...

  5. Intra-pulse Cavity Enhanced Measurements of Carbon Monoxide in a Rapid Compression Machine

    KAUST Repository

    Nasir, Ehson Fawad

    2018-05-07

    A laser absorption sensor for carbon monoxide concentration was developed for combustion studies in a rapid compression machine using a pulsed quantum cascade laser near 4.89 μm. Cavity enhancement reduced minimum detection limit down to 2.4 ppm at combustion relevant conditions. Off-axis alignment and rapid intra-pulse down-chirp resulted in effective suppression of cavity noise.

  6. Conversion of localized lower hybrid oscillations and fast magnetosonic waves at a plasma density cavity

    International Nuclear Information System (INIS)

    Hall, J.O.

    2004-01-01

    Analytic expressions are presented for conversion of localized lower hybrid oscillations and magnetosonic waves by scattering off a small scale density cavity. The governing equations are solved in slab geometry with wave vectors perpendicular to both the ambient magnetic field and the density gradient associated with density cavity using a scale length separation method. The theory predicts strong excitation of localized lower hybrid oscillations for a set of frequencies between the lower hybrid frequency of the ambient plasma and the minimum lower hybrid frequency inside the cavity. The theory is relevant for the lower hybrid solitary structures observed in space plasmas

  7. Nanometer cavities studied by positron annihilation

    International Nuclear Information System (INIS)

    Mogensen, O.E.

    1992-01-01

    Positronium (Ps) is trapped in cavities in insulating solids, and the lifetime of ortho Ps is determined by the size of the cavity. The information on the properties of the cavities obtained by use of the standard slow positron beam and the 'normal' positron annihilation techniques is compared for several selected cases. (author)

  8. Computer codes for RF cavity design

    International Nuclear Information System (INIS)

    Ko, K.

    1992-08-01

    In RF cavity design, numerical modeling is assuming an increasingly important role with the help of sophisticated computer codes and powerful yet affordable computers. A description of the cavity codes in use in the accelerator community has been given previously. The present paper will address the latest developments and discuss their applications to cavity toning and matching problems

  9. Diagram of a LEP superconducting cavity

    CERN Multimedia

    1991-01-01

    This diagram gives a schematic representation of the superconducting radio-frequency cavities at LEP. Liquid helium is used to cool the cavity to 4.5 degrees above absolute zero so that very high electric fields can be produced, increasing the operating energy of the accelerator. Superconducting cavities were used only in the LEP-2 phase of the accelerator, from 1996 to 2000.

  10. Computer codes for RF cavity design

    International Nuclear Information System (INIS)

    Ko, K.

    1992-01-01

    In RF cavity design, numerical modeling is assuming an increasingly important role with the help of sophisticated computer codes and powerful yet affordable computers. A description of the cavity codes in use in the accelerator community has been given previously. The present paper will address the latest developments and discuss their applications to cavity tuning and matching problems. (Author) 8 refs., 10 figs

  11. A Many-Atom Cavity QED System with Homogeneous Atom-Cavity Coupling

    OpenAIRE

    Lee, Jongmin; Vrijsen, Geert; Teper, Igor; Hosten, Onur; Kasevich, Mark A.

    2013-01-01

    We demonstrate a many-atom-cavity system with a high-finesse dual-wavelength standing wave cavity in which all participating rubidium atoms are nearly identically coupled to a 780-nm cavity mode. This homogeneous coupling is enforced by a one-dimensional optical lattice formed by the field of a 1560-nm cavity mode.

  12. Gastrophysics of the Oral Cavity.

    Science.gov (United States)

    Mouritsen, Ole G

    2016-01-01

    Gastrophysics is the science that pertains to the physical and physico-chemical description of the empirical world of gastronomy, with focus on sensory perception in the oral cavity and how it is related to the materials properties of food and cooking processes. Flavor (taste and smell), mouthfeel, chemesthesis, and astringency are all related to the chemical properties and the texture of the food and how the food is transformed in the oral cavity. The present topical review will primarily focus attention on the somatosensory perception of food (mouthfeel or texture) and how it interacts with basic tastes (sour, bitter, sweet, salty, and umami) and chemesthetic action. Issues regarding diet, nutrition, and health will be put into an evolutionary perspective, and some mention will be made of umami and its importance for (oral) health.

  13. Cavity Voltage Phase Modulation MD

    CERN Document Server

    Mastoridis, Themistoklis; Molendijk, John; Timko, Helga; CERN. Geneva. ATS Department

    2016-01-01

    The LHC RF/LLRF system is currently configured for extremely stable RF voltage to minimize transient beam loading effects. The present scheme cannot be extended beyond nominal beam current since the demanded power would exceed the peak klystron power and lead to saturation. A new scheme has therefore been proposed: for beam currents above nominal (and possibly earlier), the cavity phase modulation by the beam will not be corrected (transient beam loading), but the strong RF feedback and One-Turn Delay feedback will still be active for loop and beam stability in physics. To achieve this, the voltage set point will be adapted for each bunch. The goal of this MD was to test a new algorithm that would adjust the voltage set point to achieve the cavity phase modulation that would minimize klystron forward power.

  14. Improvement of cavity performance in the Saclay/Cornell/DESY's SC cavities

    International Nuclear Information System (INIS)

    Kako, E.; Noguchi, S.; Ono, M.

    2000-01-01

    Development of 1.3 GHz Nb superconducting cavities for TESLA (TeV Energy Superconducting Linear Collider) has been carried out with international collaboration. Three Saclay single-cell cavities, one Cornell two-cell cavity and one DESY nine-cell cavity were sent to KEK in order to compare the cavity performance. These cavities were tested at KEK after the following surface treatment: 1) high pressure rinsing, HPR, 2) chemical polishing and HPR, 3) electropolishing and HPR. The test results, especially, improvement of the cavity performance due to electropolishing are reported in this paper. (author)

  15. Superconducting versus normal conducting cavities

    CERN Document Server

    Podlech, Holger

    2013-01-01

    One of the most important issues of high-power hadron linacs is the choice of technology with respect to superconducting or room-temperature operation. The favour for a specific technology depends on several parameters such as the beam energy, beam current, beam power and duty factor. This contribution gives an overview of the comparison between superconducting and normal conducting cavities. This includes basic radiofrequency (RF) parameters, design criteria, limitations, required RF and plug power as well as case studies.

  16. Grinding Inside A Toroidal Cavity

    Science.gov (United States)

    Mayer, Walter; Adams, James F.; Burley, Richard K.

    1987-01-01

    Weld lines ground smooth within about 0.001 in. Grinding tool for smoothing longitudinal weld lines inside toroidal cavity includes curved tunnel jig to guide grinding "mouse" along weld line. Curvature of tunnel jig matched to shape of toroid so grinding ball in mouse follows circular arc of correct radius as mouse is pushed along tunnel. Tool enables precise control of grindout shape, yet easy to use.

  17. Optical Material Characterization Using Microdisk Cavities

    Science.gov (United States)

    Michael, Christopher P.

    Since Jack Kilby recorded his "Monolithic Idea" for integrated circuits in 1958, microelectronics companies have invested billions of dollars in developing the silicon material system to increase performance and reduce cost. For decades, the industry has made Moore's Law, concerning cost and transistor density, a self-fulfilling prophecy by integrating technical and material requirements vertically down their supply chains and horizontally across competitors in the market. At recent technology nodes, the unacceptable scaling behavior of copper interconnects has become a major design constraint by increasing latency and power consumption---more than 50% of the power consumed by high speed processors is dissipated by intrachip communications. Optical networks at the chip scale are a potential low-power high-bandwidth replacement for conventional global interconnects, but the lack of efficient on-chip optical sources has remained an outstanding problem despite significant advances in silicon optoelectronics. Many material systems are being researched, but there is no ideal candidate even though the established infrastructure strongly favors a CMOS-compatible solution. This thesis focuses on assessing the optical properties of materials using microdisk cavities with the intention to advance processing techniques and materials relevant to silicon photonics. Low-loss microdisk resonators are chosen because of their simplicity and long optical path lengths. A localized photonic probe is developed and characterized that employs a tapered optical-fiber waveguide, and it is utilized in practical demonstrations to test tightly arranged devices and to help prototype new fabrication methods. A case study in AlxGa1-xAs illustrates how the optical scattering and absorption losses can be obtained from the cavity-waveguide transmission. Finally, single-crystal Er2O3 epitaxially grown on silicon is analyzed in detail as a potential CMOS-compatable gain medium due to its high Er3

  18. Optomechanic interactions in phoxonic cavities

    Directory of Open Access Journals (Sweden)

    Bahram Djafari-Rouhani

    2014-12-01

    Full Text Available Phoxonic crystals are periodic structures exhibiting simultaneous phononic and photonic band gaps, thus allowing the confinement of both excitations in the same cavity. The phonon-photon interaction can be enhanced due to the overlap of both waves in the cavity. In this paper, we discuss some of our recent theoretical works on the strength of the optomechanic coupling, based on both photoelastic and moving interfaces mechanisms, in different (2D, slabs, strips phoxonic crystals cavities. The cases of two-dimensional infinite and slab structures will enable us to mention the important role of the symmetry and degeneracy of the modes, as well as the role of the materials whose photoelastic constants can be wavelength dependent. Depending on the phonon-photon pair, the photoelastic and moving interface mechanisms can contribute in phase or out-of-phase. Then, the main part of the paper will be devoted to the optomechanic interaction in a corrugated nanobeam waveguide exhibiting dual phononic/photonic band gaps. Such structures can provide photonic modes with very high quality factor, high frequency phononic modes of a few GHz inside a gap and optomechanical coupling rate reaching a few MHz.

  19. Investigation of superconducting niobium 1170 MHz cavities

    International Nuclear Information System (INIS)

    Anashin, V.V.; Bibko, S.I.; Fadeyev, E.I.

    1988-01-01

    The design, fabrication and experiments with superconducting L-band single cell cavities are described. These cavities model a cell of an accelerating RF structure. The cavities have been fabricated from technical grade and higher purity grade sheet niobium using deep-drawing, electron beam welding and chemical polishing. They have spherical geometry and are excited in the TM 010 mode. A computerized set-up was used for cavity tests. Qo=1.5 x 10 9 and E acc = 4.3 MV/m were obtained in the cavity made of higher purity grade niobium. 6 references, 8 figures, 3 tables

  20. LHC crab-cavity aspects and strategy

    International Nuclear Information System (INIS)

    Calaga, R.; Tomas, R.; Zimmermann, F.

    2010-01-01

    The 3rd LHC Crab Cavity workshop (LHC-CC09) took place at CERN in October 2009. It reviewed the current status and identified a clear strategy towards a future crab-cavity implementation. Following the success of crab cavities in KEK-B and the strong potential for luminosity gain and leveling, CERN will pursue crab crossing for the LHC upgrade. We present a summary and outcome of the variousworkshop sessions which have led to the LHC crab-cavity strategy, covering topics like layout, cavity design, integration, machine protection, and a potential validation test in the SPS.

  1. Image transmission through a stable paraxial cavity

    International Nuclear Information System (INIS)

    Gigan, Sylvain; Lopez, Laurent; Treps, Nicolas; Maitre, Agnes; Fabre, Claude

    2005-01-01

    We study the transmission of a monochromatic 'image' through a paraxial cavity. Using the formalism of self-transform functions, we show that a transverse degenerate cavity transmits the self-transform part of the image, with respect to the field transformation over one round-trip of the cavity. This formalism gives insight into the understanding of the behavior of a transverse degenerate cavity, complementary to the transverse mode picture. An experiment of image transmission through a hemiconfocal cavity shows the interest of this approach

  2. STRUCTURAL ANALYSIS OF SUPERCONDUCTING ACCELERATOR CAVITIES

    International Nuclear Information System (INIS)

    Schrage, D.

    2000-01-01

    The static and dynamic structural behavior of superconducting cavities for various projects was determined by finite element structural analysis. The β = 0.61 cavity shape for the Neutron Science Project was studied in detail and found to meet all design requirements if fabricated from five millimeter thick material with a single annular stiffener. This 600 MHz cavity will have a Lorentz coefficient of minus1.8 Hz/(Mv/meter) 2 and a lowest structural resonance of more than 100 Hz. Cavities at β = 0.48, 0.61, and 0.77 were analyzed for a Neutron Science Project concept which would incorporate 7-cell cavities. The medium and high beta cavities were found to meet all criteria but it was not possible to generate a β = 0.48 cavity with a Lorentz coefficient of less than minus3 Hz/(Mv/meter) 2

  3. Cavity Optomechanics at Millikelvin Temperatures

    Science.gov (United States)

    Meenehan, Sean Michael

    The field of cavity optomechanics, which concerns the coupling of a mechanical object's motion to the electromagnetic field of a high finesse cavity, allows for exquisitely sensitive measurements of mechanical motion, from large-scale gravitational wave detection to microscale accelerometers. Moreover, it provides a potential means to control and engineer the state of a macroscopic mechanical object at the quantum level, provided one can realize sufficiently strong interaction strengths relative to the ambient thermal noise. Recent experiments utilizing the optomechanical interaction to cool mechanical resonators to their motional quantum ground state allow for a variety of quantum engineering applications, including preparation of non-classical mechanical states and coherent optical to microwave conversion. Optomechanical crystals (OMCs), in which bandgaps for both optical and mechanical waves can be introduced through patterning of a material, provide one particularly attractive means for realizing strong interactions between high-frequency mechanical resonators and near-infrared light. Beyond the usual paradigm of cavity optomechanics involving isolated single mechanical elements, OMCs can also be fashioned into planar circuits for photons and phonons, and arrays of optomechanical elements can be interconnected via optical and acoustic waveguides. Such coupled OMC arrays have been proposed as a way to realize quantum optomechanical memories, nanomechanical circuits for continuous variable quantum information processing and phononic quantum networks, and as a platform for engineering and studying quantum many-body physics of optomechanical meta-materials. However, while ground state occupancies (that is, average phonon occupancies less than one) have been achieved in OMC cavities utilizing laser cooling techniques, parasitic absorption and the concomitant degradation of the mechanical quality factor fundamentally limit this approach. On the other hand, the high

  4. Cavities

    Science.gov (United States)

    ... in protein, vitamins, and minerals, such as meats, poultry, grains, and fresh fruits and vegetables, tend to ... treat dry socket? Antibiotics taken by mouth A dressing soaked with an anesthetic Codeine Ear drops to ...

  5. Temperature Structure of a Coronal Cavity

    Science.gov (United States)

    Kucera, T. A.; Gibson, S. E.; Schmit, D. J.

    2011-01-01

    we analyze the temperature structure of a coronal cavity observed in Aug. 2007. coronal cavities are long, low-density structures located over filament neutral lines and are often seen as dark elliptical features at the solar limb in white light, EUV and x-rays. when these structures erupt they form the cavity portions of CMEs. It is important to establish the temperature structure of cavities in order to understand the thermodynamics of cavities in relation to their three-dimensional magnetic structure. To analyze the temperature we compare temperature ratios of a series of iron lines observed by the Hinode/EUv Imaging spectrometer (EIS). We also use those lines to constrain a forward model of the emission from the cavity and streamer. The model assumes a coronal streamer with a tunnel-like cavity with elliptical cross-section and a Gaussian variation of height along the tunnel lenth. Temperature and density can be varied as a function of altitude both in the cavity and streamer. The general cavity morphology and the cavity and streamer density have already been modeled using data from STEREO's SECCHI/EUVI and Hinode/EIS (Gibson et al 2010 and Schmit & Gibson 2011).

  6. Hybrid Vertical-Cavity Laser

    DEFF Research Database (Denmark)

    2010-01-01

    The present invention provides a light source (2) for light circuits on a silicon platform (3). A vertical laser cavity is formed by a gain region (101) arranged between a top mirror (4) and a bottom grating-mirror (12) in a grating region (11) in a silicon layer (10) on a substrate. A waveguide...... (18, 19) for receiving light from the grating region (11) is formed within or to be connected to the grating region, and functions as an 5 output coupler for the VCL. Thereby, vertical lasing modes (16) are coupled to lateral in-plane modes (17, 20) of the in-plane waveguide formed in the silicon...

  7. Cancer of the oral cavity.

    Science.gov (United States)

    Montero, Pablo H; Patel, Snehal G

    2015-07-01

    Cancer of the oral cavity is one of the most common malignancies worldwide. Although early diagnosis is relatively easy, presentation with advanced disease is not uncommon. The standard of care is primary surgical resection with or without postoperative adjuvant therapy. Improvements in surgical techniques combined with the routine use of postoperative radiation or chemoradiation therapy have resulted in improved survival. Successful treatment is predicated on multidisciplinary treatment strategies to maximize oncologic control and minimize impact of therapy on form and function. Prevention of oral cancer requires better education about lifestyle-related risk factors, and improved awareness and tools for early diagnosis. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Cantilever piezoelectric energy harvester with multiple cavities

    International Nuclear Information System (INIS)

    S Srinivasulu Raju; M Umapathy; G Uma

    2015-01-01

    Energy harvesting employing piezoelectric materials in mechanical structures such as cantilever beams, plates, diaphragms, etc, has been an emerging area of research in recent years. The research in this area is also focused on structural tailoring to improve the harvested power from the energy harvesters. Towards this aim, this paper presents a method for improving the harvested power from a cantilever piezoelectric energy harvester by introducing multiple rectangular cavities. A generalized model for a piezoelectric energy harvester with multiple rectangular cavities at a single section and two sections is developed. A method is suggested to optimize the thickness of the cavities and the number of cavities required to generate a higher output voltage for a given cantilever beam structure. The performance of the optimized energy harvesters is evaluated analytically and through experimentation. The simulation and experimental results show that the performance of the energy harvester can be increased with multiple cavities compared to the harvester with a single cavity. (paper)

  9. Mounting system for optical frequency reference cavities

    Science.gov (United States)

    Notcutt, Mark (Inventor); Hall, John L. (Inventor); Ma, Long-Sheng (Inventor)

    2008-01-01

    A technique for reducing the vibration sensitivity of laser-stabilizing optical reference cavities is based upon an improved design and mounting method for the cavity, wherein the cavity is mounted vertically. It is suspended at one plane, around the spacer cylinder, equidistant from the mirror ends of the cavity. The suspension element is a collar of an extremely low thermal expansion coefficient material, which surrounds the spacer cylinder and contacts it uniformly. Once the collar has been properly located, it is cemented in place so that the spacer cylinder is uniformly supported and does not have to be squeezed at all. The collar also includes a number of cavities partially bored into its lower flat surface, around the axial bore. These cavities are support points, into which mounting base pins will be inserted. Hence the collar is supported at a minimum of three points.

  10. Development of superconducting cavities at JAERI

    International Nuclear Information System (INIS)

    Ouchi, N.

    2001-01-01

    Development of superconducting (SC) cavities is continued for the high intensity proton accelerator in JAERI. In FY-1999, we carried out R and D work; (1) 2nd vertical test of β=0.886 single-cell cavity, (2) vertical test for observation of Q-disease without heat treatment after electropolishing, (3) vertical test of β=0.5 5-cell cavity, (4) pretuning, surface treatment and vertical test of β=0.886 5-cell cavity, (5) pulsed operation of β=0.886 single-cell cavity in the vertical test to confirm the validity of a new model calculation. This paper describes the present status of the R and D work for the SC cavities in JAERI. (author)

  11. Esthesioneuroblastoma of the nasal cavity.

    Science.gov (United States)

    Hollen, Tyler R; Morris, Christopher G; Kirwan, Jessica M; Amdur, Robert J; Werning, John W; Vaysberg, Mikhail; Mendenhall, William M

    2015-06-01

    Esthesioneuroblastoma is an uncommon cancer of the nasal cavity. We describe the outcomes for 26 patients treated with curative intent with photon radiotherapy (RT) at the University of Florida. Between May 1972 and June 2007, 26 patients received RT for previously untreated esthesioneuroblastoma of the nasal cavity. Sixteen patients were males and 10 were females with a median age of 55 years (range, 3 to 82 y). The modified Kadish stage distribution was: B, 7 patients; C, 17 patients; and D, 2 patients. Treatment modalities included the following: definitive RT, 5 patients; preoperative RT, 2 patients; and postoperative RT after resection, 19 patients. Elective neck irradiation (ENI) was performed in 17 (71%) of 24 N0 patients. Rates of local control, cause-specific survival, and absolute overall survival at 5 years were 79%, 72%, and 69%, respectively. Overall survival among patients treated with definitive RT was 20% at 5 years, compared with 81% among those who underwent surgery and adjuvant RT (P=0.01). One (6%) of 17 patients who received ENI developed a recurrence in the neck and was successfully salvaged. Ultimate neck control was 100% at 5 years for patients who received ENI versus 69% among those not receiving ENI (P=0.0173). Resection combined with adjuvant RT is more effective than surgery or RT alone in the treatment of esthesioneuroblastoma. ENI reduces the risk of regional relapse in patients with Kadish stage B and C cancers.

  12. Synchro-Betatron Stop-Bands Due to a Single Crab Cavity

    Energy Technology Data Exchange (ETDEWEB)

    Chao, A

    2004-06-17

    We analyze the stop-band due to crab cavities for horizontal tunes that are either close to integers or close to half integers. The latter case is relevant for today's electron/positron colliders. We compare this stop-band to that created by dispersion in an accelerating cavity and show that a single typical crab cavity creates larger stop-bands than a typical dispersion at an accelerating cavity. We furthermore analyze whether it is beneficial to place the crab cavity at a position where the dispersion and its slope vanish. We find that this choice is worth while if the horizontal tune is close to a half integer, but not if it is close to an integer. Furthermore we find that stop-bands can be avoided when the horizontal tune is located at a favorable side of the integer or the half integer. While we are here concerned with the installation of a single crab cavity in a storage ring, we show that the stop-bands can be weakened, although not eliminated, significantly when two crab cavities per ring are chosen suitably.

  13. Design of 325 MHz spoke cavity

    International Nuclear Information System (INIS)

    Sha Peng; Huang Hong; Dai Jianping; Zu Guoquan; Li Han

    2012-01-01

    Spoke cavity can be used in the low-energy section of the proton accelerator. It has many significant advantages: compact structure, high value of R/Q, etc. The ADS (Accelerator Driven System) project will adopt many spoke cavities with different β values. Therefore, IHEP has began the research of β=0.14, 325 MHz spoke cavity. In this pa per, the dimensions, RF performances and mechanical properties of it are studied. (authors)

  14. A superconducting test cavity for DORIS

    International Nuclear Information System (INIS)

    Bauer, W.; Brandelik, A.; Lekmann, W.; Szecsi, L.

    1978-03-01

    A summary of experimental goals, technical requirements and possible solutions for the construction of a superconducting accelerating cavity to be tested at DORIS is given. The aim of the experiment is to prove the applicability of superconducting cavities in storage rings and to study the problems typical for this application. The paper collects design considerations about cavity geometry and fabrication, input coupling, output coupling for higher modes, tuner, cryostat and controls. (orig.) [de

  15. Dither Cavity Length Controller with Iodine Locking

    Directory of Open Access Journals (Sweden)

    Lawson Marty

    2016-01-01

    Full Text Available A cavity length controller for a seeded Q-switched frequency doubled Nd:YAG laser is constructed. The cavity length controller uses a piezo-mirror dither voltage to find the optimum length for the seeded cavity. The piezo-mirror dither also dithers the optical frequency of the output pulse. [1]. This dither in optical frequency is then used to lock to an Iodine absorption line.

  16. Optical microfiber-based photonic crystal cavity

    International Nuclear Information System (INIS)

    Yu, Yang; Sun, Yi-zhi; Li, Zhi-yuan; Ding, Wei; Andrews, Steve

    2016-01-01

    Using a focused ion beam milling technique, we fabricate broad stop band (∼10% wide) photonic crystal (PhC) cavities in adiabatically-tapered silica fibers. Abrupt structural design of PhC mirrors efficiently reduces radiation loss, increasing the cavity finesse to ∼7.5. Further experiments and simulations verify that the remaining loss is mainly due to Ga ion implantation. Such a microfiber PhC cavity probably has potentials in many light-matter interaction applications. (paper)

  17. Stochastic transition of free motion in billiards with borders given by equipotential lines of the diamagnetic Kepler problem

    International Nuclear Information System (INIS)

    Abul-Magd, A.Y.; Mueller, K.

    1992-01-01

    We compare the transition from ordered to chaotic motion in a potential with that in a billiard, whose borders are defined by the maximal equipotential line of the potential system in the case of hydrogen in a uniform magnetic field. For the billiard we calculate the Poincare maps, the fraction of regular motion on the surface of section, and the stability properties of the shortest periodic orbits. In contrast to the H atom, the billiard shows a generic transition to chaos. While the shape of the orbits is determined by the boundary and is thus very similar, their properties of stability are different: The potential tends to stabilize the motion. The onset of instability in the billiard can be understood in terms of the curvature of the boundary; for the potential system the Gaussian curvature of the potential-energy surface is shown to be the relevant parameter

  18. Entanglement and bistability in coupled quantum dots inside a driven cavity

    International Nuclear Information System (INIS)

    Mitra, Arnab; Vyas, Reeta

    2010-01-01

    Generation and dissipation of entanglement between two coupled quantum dots (QDs) in a cavity driven by a coherent field is studied. We find that it is possible to generate and sustain a large amount of entanglement between the quantum dots in the steady state, even in the presence of strong decay in both the cavity and the dots. We investigate the effect of different parameters (decay rates, coupling strengths, and detunings) on entanglement. We find that the cavity field shows bistability and study the effect of relevant parameters on the existence of this bistable behavior. We also study the correlation between the cavity field and the entanglement between the dots. The experimental viability of the proposed scheme is discussed.

  19. Superconducting cavity driving with FPGA controller

    International Nuclear Information System (INIS)

    Czarski, Tomasz; Koprek, Waldemar; Pozniak, Krzysztof T.; Romaniuk, Ryszard S.; Simrock, Stefan; Brandt, Alexander; Chase, Brian; Carcagno, Ruben; Cancelo, Gustavo; Koeth, Timothy W.

    2006-01-01

    A digital control of superconducting cavities for a linear accelerator is presented. FPGA-based controller, supported by Matlab system, was applied. Electrical model of a resonator was used for design of a control system. Calibration of the signal path is considered. Identification of cavity parameters has been carried out for adaptive control algorithm. Feed-forward and feedback modes were applied in operating the cavities. Required performance has been achieved; i.e. driving on resonance during filling and field stabilization during flattop time, while keeping reasonable level of the power consumption. Representative results of the experiments are presented for different levels of the cavity field gradient

  20. Optically coupled cavities for wavelength switching

    Energy Technology Data Exchange (ETDEWEB)

    Costazo-Caso, Pablo A; Granieri, Sergio; Siahmakoun, Azad, E-mail: pcostanzo@ing.unlp.edu.ar, E-mail: granieri@rose-hulman.edu, E-mail: siahmako@rose-hulman.edu [Department of Physics and Optical Engineering, Rose-Hulman Institute of Technology, 5500 Wabash Avenue, Terre Haute, IN 47803 (United States)

    2011-01-01

    An optical bistable device which presents hysteresis behavior is proposed and experimentally demonstrated. The system finds applications in wavelength switching, pulse reshaping and optical bistability. It is based on two optically coupled cavities named master and slave. Each cavity includes a semiconductor optical amplifier (SOA), acting as the gain medium of the laser, and two pair of fiber Bragg gratings (FBG) which define the lasing wavelength (being different in each cavity). Finally, a variable optical coupler (VOC) is employed to couple both cavities. Experimental characterization of the system performance is made analyzing the effects of the coupling coefficient between the two cavities and the driving current in each SOA. The properties of the hysteretic bistable curve and switching can be controlled by adjusting these parameters and the loss in the cavities. By selecting the output wavelength ({lambda}{sub 1} or {lambda}{sub 2}) with an external filter it is possible to choose either the invert or non-invert switched signal. Experiments were developed employing both optical discrete components and a photonic integrated circuit. They show that for 8 m-long cavities the maximum switching frequency is about 500 KHz, and for 4 m-long cavities a minimum rise-time about 21 ns was measured. The switching time can be reduced by shortening the cavity lengths and using photonic integrated circuits.

  1. LARGE-SCALE FLOWS IN PROMINENCE CAVITIES

    International Nuclear Information System (INIS)

    Schmit, D. J.; Gibson, S. E.; Tomczyk, S.; Reeves, K. K.; Sterling, Alphonse C.; Brooks, D. H.; Williams, D. R.; Tripathi, D.

    2009-01-01

    Regions of rarefied density often form cavities above quiescent prominences. We observed two different cavities with the Coronal Multichannel Polarimeter on 2005 April 21 and with Hinode/EIS on 2008 November 8. Inside both of these cavities, we find coherent velocity structures based on spectral Doppler shifts. These flows have speeds of 5-10 km s -1 , occur over length scales of tens of megameters, and persist for at least 1 hr. Flows in cavities are an example of the nonstatic nature of quiescent structures in the solar atmosphere.

  2. Fluid Density and Impact Cavity Formation

    Directory of Open Access Journals (Sweden)

    Ga-Chun Lin

    2018-01-01

    Full Text Available Characteristics of the impact cavity formed when a steel ball is dropped into aqueous solutions of densities ranging from 0.98 g·cm-3 to 1.63 g·cm-3 were investigated. A high-speed camera was used to record the formation and collapse of the cavity. The results showed cavity diameter, volume, and pinch-off time are independent of fluid density, on average. There was an unexplained reduction in cavity formation for densities of 1.34 g·cm-3 and 1.45 g·cm-3.

  3. Making Deferred Taxes Relevant

    NARCIS (Netherlands)

    Brouwer, Arjan; Naarding, Ewout

    2018-01-01

    We analyse the conceptual problems in current accounting for deferred taxes and provide solutions derived from the literature in order to make International Financial Reporting Standards (IFRS) deferred tax numbers value-relevant. In our view, the empirical results concerning the value relevance of

  4. Parsimonious relevance models

    NARCIS (Netherlands)

    Meij, E.; Weerkamp, W.; Balog, K.; de Rijke, M.; Myang, S.-H.; Oard, D.W.; Sebastiani, F.; Chua, T.-S.; Leong, M.-K.

    2008-01-01

    We describe a method for applying parsimonious language models to re-estimate the term probabilities assigned by relevance models. We apply our method to six topic sets from test collections in five different genres. Our parsimonious relevance models (i) improve retrieval effectiveness in terms of

  5. Thermally Activated Paramagnets from Diamagnetic Polymers of Biphenyl-3,5-diyl Bis(tert-butyl Nitroxides Carrying Methyl and Fluoro Groups at the 2’- and 5’-Positions

    Directory of Open Access Journals (Sweden)

    Toru Yoshitake

    2016-03-01

    Full Text Available Three new biradicals—2’,5’-dimethyl-, 2’-fluoro-5’-methyl-, and 5’-fluoro-2’-methyl- biphenyl-3,5-diyl bis(tert-butyl nitroxides—were synthesized. The magnetic susceptibility measurements revealed their diamagnetism below and around room temperature. The nitroxide groups are located close to each other in an intermolecular fashion to form a weakly covalent head-to-tail (NO2 ring. Biradical molecules are connected on both radical sites, constructing a diamagnetic chain. The dimethyl derivative underwent a structural phase transition at 83 °C, clarified via differential scanning calorimetry and powder X-ray diffraction, and a paramagnetic solid phase with S = 1 irreversibly appeared. The other analogues exhibited a similar irreversible upsurge of the magnetic susceptibility on heating, but the transition was characterized as the melting.

  6. NMR study of the structure and ion transport in the M1-xRxF2+x diamagnetic solid electrolytes

    International Nuclear Information System (INIS)

    Matsulv, A.N.; Nuznik, V.M.; Livshits, A.I.; Fedorov, P.P.; Sobolev, B.P.

    1988-01-01

    Monocrystalline samples of Sr 0.75 La 0.25 F 2.25 and Ba 0.75 Y 0.25 F 2.25 solid electrolytes, which belong to diamagnetic fluorite-like solid solutions, are investigated using 19 F continuous NMR method at 48 MHz frequency. Comparison of theoretical calculations and experimental data has allowed to attach component-spectra to two structural positions - F l main lattice one and F i interstitial one. A technique is suggested, and evaluation of density of structural positions is made on the basis of orientational dependences of spectra secondary moment. Change of spectra form and dispersion on heating is characteristic one for samples with ion diffusive movement. Analysis of experimental data has allowed to determine, that anionic systems of solid solutions are dinamically heterogeneous. At 290-470 K temperatures the florine ions of both types (F l and F i ) contribute to the ionic conductivity. Within this temperature range movement of the bulk of fluorine ions is more, than 10 4 Hz. Measurements, conducted for Sr 0.75 La 0.25 F 2.25 have shown, that fluorine ions in the interstitial positions are more mobile, than in the lattice ones

  7. Two-dimensional Haeckelite NbS{sub 2}. A diamagnetic high-mobility semiconductor with Nb{sup 4+} ions

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Yandong; Kuc, Agnieszka; Jing, Yu; Heine, Thomas [Wilhelm-Ostwald-Institut fuer Physikalische und Theoretische Chemie, Universitaet Leipzig (Germany); Philipsen, Pier [Scientific Computing and Modelling NV, Amsterdam (Netherlands)

    2017-08-14

    In all known Group 5 transition-metal dichalcogenide monolayers (MLs), the metal centers carry a spin, and their ground-state phases are either metallic or semiconducting with indirect band gaps. Here, on grounds of first-principles calculations, we report that the Haeckelite polytypes 1S-NbX{sub 2} (X=S, Se, Te) are diamagnetic direct-band-gap semiconductors even though the Nb atoms are in the 4+ oxidation state. In contrast, 1S-VX{sub 2} MLs are antiferromagnetically coupled indirect-band-gap semiconductors. The 1S phases are thermodynamically and dynamically stable but of slightly higher energy than their 1H and 1T ML counterparts. 1S-NbX{sub 2} MLs are excellent candidates for optoelectronic applications owing to their small band gaps (between 0.5 and 1 eV). Moreover, 1S-NbS{sub 2} shows a particularly high hole mobility of 2.68 x 10{sup 3} cm{sup 2} V{sup -1} s{sup -1}, which is significantly higher than that of MoS{sub 2} and comparable to that of WSe{sub 2}. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Structure, spectra and thermal, mechanical, Faraday rotation properties of novel diamagnetic SeO2-PbO-Bi2O3-B2O3 glasses

    Science.gov (United States)

    Chen, Qiuling; Su, Kai; Li, Yantao; Zhao, Zhiwei

    2018-06-01

    Faraday rotation diamagnetic glass has attracted research attentions in photonics, sensing and magneto optical devices due to their high refractive index, wide transmittance in UV and Fourier transform infrared (FT-IR) range and temperature independent Faraday rotation. Selenite modified heavy metal oxides glasses with composition of xSeO2-(10-x) B2O3-45PbO-45Bi2O3 (x = 0, 1, 5 and 10mol%) and 15%SeO2-40%PbO-45%Bi2O3 have been fabricated by melt-quenching method in present study. The influence of SeO2 on glass forming ability, thermal, mechanical properties and Faraday rotation were evaluated through X-ray Diffraction (XRD), Fourier transforms infrared spectra (FT-IR), Raman, X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC), Vicker's hardness and Verdet constant measurements. XRD spectra reveal that the good vitrification was achieved for glass with SeO2 amounts ≤10% even without B2O3. FT-IR, Raman and XPS spectra ascertain the existence of characteristic vibration of SeO4, SeO3, PbO4, BiO3 and BO3 units. The incorporation of SeO2 increases the connectivity of glassy network by increasing the Tg, thermal stability and mechanical hardness. The small band gap, high polarizable Se4+ ions and isolated SeO3 units contribute to Faraday rotation improvement.

  9. Field emitted electron trajectories for the CEBAF cavity

    International Nuclear Information System (INIS)

    Yunn, B.C.; Sundelin, R.M.

    1993-06-01

    Electromagnetic fields of the superconducting 5-cell CEBAF cavity with its fundamental power coupler are solved numerically with URMEL and MAFIA codes. Trajectories of field emitted electrons following the Fowler-Nordheim relation are studied with a numerical program which accepts the URMEL/MAFIA fields. Emission sites and gradients are determined for those electrons which can reach the cold ceramic window either directly or by an energetic backscattering. The peak and average impact energy and current are found. The generation of dark current by field emitted electrons has also been studied, and its relevance to CEBAF operation is briefly discussed

  10. Hydrodynamic Drag on Streamlined Projectiles and Cavities

    KAUST Repository

    Jetly, Aditya

    2016-04-19

    The air cavity formation resulting from the water-entry of solid objects has been the subject of extensive research due to its application in various fields such as biology, marine vehicles, sports and oil and gas industries. Recently we demonstrated that at certain conditions following the closing of the air cavity formed by the initial impact of a superhydrophobic sphere on a free water surface a stable streamlined shape air cavity can remain attached to the sphere. The formation of superhydrophobic sphere and attached air cavity reaches a steady state during the free fall. In this thesis we further explore this novel phenomenon to quantify the drag on streamlined shape cavities. The drag on the sphere-cavity formation is then compared with the drag on solid projectile which were designed to have self-similar shape to that of the cavity. The solid projectiles of adjustable weight were produced using 3D printing technique. In a set of experiments on the free fall of projectile we determined the variation of projectiles drag coefficient as a function of the projectiles length to diameter ratio and the projectiles specific weight, covering a range of intermediate Reynolds number, Re ~ 104 – 105 which are characteristic for our streamlined cavity experiments. Parallel free fall experiment with sphere attached streamlined air cavity and projectile of the same shape and effective weight clearly demonstrated the drag reduction effect due to the stress-free boundary condition at cavity liquid interface. The streamlined cavity experiments can be used as the upper bound estimate of the drag reduction by air layers naturally sustained on superhydrophobic surfaces in contact with water. In the final part of the thesis we design an experiment to test the drag reduction capacity of robust superhydrophobic coatings deposited on the surface of various model vessels.

  11. Superconducting cavities developments efforts at RRCAT

    International Nuclear Information System (INIS)

    Puntambekar, A.; Bagre, M.; Dwivedi, J.; Shrivastava, P.; Mundra, G.; Joshi, S.C.; Potukuchi, P.N.

    2011-01-01

    Superconducting RE cavities are the work-horse for many existing and proposed linear accelerators. Raja Ramanna Centre for Advanced Technology (RRCAT) has initiated a comprehensive R and D program for development of Superconducting RF cavities suitable for high energy accelerator application like SNS and ADS. For the initial phase of technology demonstration several prototype 1.3 GHz single cell-cavities have been developed. The work began with development of prototype single cell cavities in aluminum and copper. This helped in development of cavity manufacturing process, proving various tooling and learning on various mechanical and RF qualification processes. The parts manufacturing was done at RRCAT and Electron beam welding was carried out at Indian industry. These cavities further served during commissioning trials for various cavity processing infrastructure being developed at RRCAT and are also a potential candidate for Niobium thin film deposition R and D. Based on the above experience, few single cell cavities were developed in fine grain niobium. The critical technology of forming and machining of niobium and the intermediate RF qualification were developed at RRCAT. The EB welding of bulk niobium cavities was carried out in collaboration with IUAC, New Delhi at their facility. As a next logical step efforts are now on for development of multicell cavities. The prototype dumbbells and end group made of aluminium, comprising of RF and HOM couplers ports have also been developed, with their LB welding done at Indian industry. In this paper we shall present the development efforts towards manufacturing of 1.3 GHz single cell cavities and their initial processing and qualification. (author)

  12. Geophysical observations at cavity collapse

    Science.gov (United States)

    Jousset, Philippe; Bazargan-Sabet, Behrooz; Lebert, François; Bernardie, Séverine; Gourry, Jean-Christophe

    2010-05-01

    In Lorraine region (France) salt layers at about 200 meters depth are exploited by Solvay using solution mining methodology which consists in extracting the salt by dissolution, collapsing the cavern overburden during the exploitation phase and finally reclaiming the landscape by creating a water area. In this process, one of the main challenges for the exploiting company is to control the initial 120-m diameter collapse so as to minimize possible damages. In order to detect potential precursors and understand processes associated with such collapses, a wide series of monitoring techniques including micro seismics, broad-band seismology, hydro-acoustic, electromagnetism, gas probing, automatic leveling, continuous GPS, continuous gravity and borehole extensometry was set-up in the frame of an in-situ study carried out by the "Research Group for the Impact and Safety of Underground Works" (GISOS, France). Equipments were set-up well before the final collapse, giving a unique opportunity to analyze a great deal of information prior to and during the collapse process which has been successfully achieved on February the 13th, 2009 by controlling the cavity internal pressure. In this work, we present the results of data recorded by a network of 3 broadband seismometers, 2 accelerometers, 2 tilt-meters and a continuously gravity meter. We relate the variations of the brine pumping rate with the evolutions of the induced geophysical signals and finally we propose a first mechanical model for describing the controlled collapse. Beyond the studied case, extrapolation of the results obtained might contribute to the understanding of uncontrolled cavity collapses, such as pit-craters or calderas at volcanoes.

  13. Ultimate Cavity Dynamics of Hydrophobic Spheres Impacting on Free Water Surfaces

    KAUST Repository

    Mansoor, Mohammad M.

    2012-12-01

    Cavity formation resulting from the water-entry of solid objects has been the subject of extensive research owing to its practical relevance in naval, military, industrial, sports and biological applications. The cavity formed by an impacting hydrophobic sphere normally seals at two places, one below (deep seal) and the other above the water surface (surface seal). For Froude numbers , the air flow into the resulting cavity is strong enough to suck the splash crown above the surface and disrupt the cavity dynamics before it deep seals. In this research work we eliminate surface seals by means of a novel practice of using cone splash-guards and examine the undisturbed transient cavity dynamics by impact of hydrophobic spheres for Froude numbers ranging . This enabled the measurement of extremely accurate pinch-off heights, pinch-off times, radial cavity collapse rates, and jet speeds in an extended range of Froude numbers compared to the previous work of Duclaux et al. (2007). Results in the extended regime were in remarkable agreement with the theoretical prediction of scaled pinch-off depth, and experimentally derived pinch-off time for . Furthermore, we investigated the influence of confinement on cavity formation by varying the cross-sectional area of the tank of liquid. In conjunction with surface seal elimination we observed the formation of multiple pinch-off points where a maximum of four deep seals were obtained in a sequential order for the Froude number range investigated. The presence of an elongated cavity beneath the first pinch-off point 5 resulted in evident "kinks" primarily related to the greatly diminished air pressure at the necking region caused by supersonic air flows (Gekle et al. 2010). Such flows passing through second pinch-offs were also found to choke the cavities beneath the first pinch- off depths causing radial expansion and hence disappearance of downward jets.

  14. Cavity pressure history of contained nuclear explosions

    Energy Technology Data Exchange (ETDEWEB)

    Chapin, C E [Lawrence Radiation Laboratory, University of California, Livermore, CA (United States)

    1970-05-01

    Knowledge of pressure in cavities created by contained nuclear explosions is useful for estimating the possibility of venting radioactive debris to the atmosphere. Measurements of cavity pressure, or temperature, would be helpful in evaluating the correctness of present code predictions of underground explosions. In instrumenting and interpreting such measurements it is necessary to have good theoretical estimates of cavity pressures. In this paper cavity pressure is estimated at the time when cavity growth is complete. Its subsequent decrease due to heat loss from the cavity to the surrounding media is also predicted. The starting pressure (the pressure at the end of cavity growth) is obtained by adiabatic expansion to the final cavity size of the vaporized rock gas sphere created by the explosion. Estimates of cavity size can be obtained by stress propagation computer codes, such as SOC and TENSOR. However, such estimates require considerable time and effort. In this paper, cavity size is estimated using a scheme involving simple hand calculations. The prediction is complicated by uncertainties in the knowledge of silica water system chemistry and a lack of information concerning possible blowoff of wall material during cavity growth. If wall material blows off, it can significantly change the water content in the cavity, compared to the water content in the ambient media. After cavity growth is complete, the pressure will change because of heat loss to the surrounding media. Heat transfer by convection, radiation and conduction is considered, and its effect on the pressure is calculated. Analysis of cavity heat transfer is made difficult by the complex nature of processes which occur at the wall where melting, vaporization and condensation of the gaseous rock can all occur. Furthermore, the melted wall material could be removed by flowing or dripping to the cavity floor. It could also be removed by expansion of the steam contained in the melt (blowoff) and by

  15. The gastro-oesophageal common cavity revisited

    NARCIS (Netherlands)

    Aanen, M. C.; Bredenoord, A. J.; Samsom, M.; Smout, A. J. P. M.

    2006-01-01

    The manometric common cavity phenomenon has been used as indicator of gastro-oesophageal reflux of liquid or gaseous substances. Using combined pH and impedance recording as reference standard the value of a common cavity as indicator of gastro-oesophageal reflux was tested. Ten healthy male

  16. Geometric Model of a Coronal Cavity

    Science.gov (United States)

    Kucera, Therese A.; Gibson, S. E.; Ratawicki, D.; Dove, J.; deToma, G.; Hao, J.; Hudson, H. S.; Marque, C.; McIntosh, P. S.; Reeves, K. K.; hide

    2010-01-01

    We observed a coronal cavity from August 8-18 2007 during a multi-instrument observing campaign organized under the auspices of the International Heliophysical Year (IHY). Here we present initial efforts to model the cavity with a geometrical streamer-cavity model. The model is based the white-light streamer mode] of Gibson et a]. (2003 ), which has been enhanced by the addition of a cavity and the capability to model EUV and X-ray emission. The cavity is modeled with an elliptical cross-section and Gaussian fall-off in length and width inside the streamer. Density and temperature can be varied in the streamer and cavity and constrained via comparison with data. Although this model is purely morphological, it allows for three-dimensional, multi-temperature analysis and characterization of the data, which can then provide constraints for future physical modeling. Initial comparisons to STEREO/EUVI images of the cavity and streamer show that the model can provide a good fit to the data. This work is part of the effort of the International Space Science Institute International Team on Prominence Cavities

  17. Radiation injuries of the oral cavity

    International Nuclear Information System (INIS)

    Galantseva, G.F.

    1982-01-01

    The review is given of factors which cause the beginning of radiation injuries of oral cavity in oncologic patients following radiotherapy: dose rate absorbed with tumor and surrounding healthy tissues; irradiation procedures; size of irradiated volume. Pathogenesis and clinical picture are considered as well as prophylaxis and tactics of treatments of patients with radiation injuries of oral cavity

  18. Cavity enhancement by controlled directional scattering

    Science.gov (United States)

    Winston, R.

    1980-01-01

    A method for designing cavity enclosures is presented that can be applied to the design of a nonimaging concentrator. The method maintains high transmission at the expense of some concentration in the presence of a gap between the reflector and the receiver. The slight loss of concentration may be partly offset by enhanced absorption of radiation by the receiver, resulting from the cavity effect.

  19. Large grain cavities from pure niobium ingot

    Science.gov (United States)

    Myneni, Ganapati Rao [Yorktown, VA; Kneisel, Peter [Williamsburg, VA; Cameiro, Tadeu [McMurray, PA

    2012-03-06

    Niobium cavities are fabricated by the drawing and ironing of as cast niobium ingot slices rather than from cold rolled niobium sheet. This method results in the production of niobium cavities having a minimum of grain boundaries at a significantly reduced cost as compared to the production of such structures from cold rolled sheet.

  20. Dissipative preparation of entanglement in optical cavities

    DEFF Research Database (Denmark)

    Kastoryano, Michael James; Reiter, Florentin; Sørensen, Anders Søndberg

    2011-01-01

    We propose a novel scheme for the preparation of a maximally entangled state of two atoms in an optical cavity. Starting from an arbitrary initial state, a singlet state is prepared as the unique fixed point of a dissipative quantum dynamical process. In our scheme, cavity decay is no longer...

  1. Toroidal 12 cavity klystron : a novel approach

    International Nuclear Information System (INIS)

    Hazarika, A.B.R.

    2013-01-01

    A toroidal 12 cavity klystron is designed to provide with high energy power with the high frequency microwave RF- plasma generated from it. The cavities are positioned in clock hour positions. The theoretical modeling and designing is done to study the novel approach. (author)

  2. Superconducting rf cavities for accelerator application

    International Nuclear Information System (INIS)

    Proch, D.

    1988-01-01

    The subject of this paper is a review of superconducting cavities for accelerator application (β = 1). The layout of a typical accelerating unit is described and important parameters are discussed. Recent cavity measurements and storage ring beam tests are reported and the present state of the art is summarized

  3. Dispersion of coupled mode-gap cavities

    NARCIS (Netherlands)

    Lian, Jin; Sokolov, Sergei; Yuce, E.; Combrie, S.; de Rossi, A.; Mosk, Allard

    2015-01-01

    The dispersion of a coupled resonator optical waveguide made of photonic crystal mode-gap cavities is pronouncedly asymmetric. This asymmetry cannot be explained by the standard tight binding model. We show that the fundamental cause of the asymmetric dispersion is the inherent dispersive cavity

  4. Preliminary simulation studies of accelerator cavity loading

    International Nuclear Information System (INIS)

    Faehl, R.J.

    1980-06-01

    Two-dimensional simulations of loading effects in a 350 MHz accelerator cavity have been performed. Electron currents of 1-10 kA have been accelerated in 5 MV/m fields. Higher order cavity modes induced by the beam may lead to emittance growth. Operation in an autoaccelerator mode has been studied

  5. Fast thermometry for superconducting rf cavity testing

    International Nuclear Information System (INIS)

    Orris, Darryl; Bellantoni, Leo; Carcagno, Ruben H.; Edwards, Helen; Harms, Elvin Robert; Khabiboulline, Timergali N.; Kotelnikov, Sergey; Makulski, Andrzej; Nehring, Roger; Pischalnikov, Yuriy; Fermilab

    2007-01-01

    Fast readout of strategically placed low heat capacity thermometry can provide valuable information of Superconducting RF (SRF) cavity performance. Such a system has proven very effective for the development and testing of new cavity designs. Recently, several resistance temperature detectors (RTDs) were installed in key regions of interest on a new 9 cell 3.9 GHz SRF cavity with integrated HOM design at FNAL. A data acquisition system was developed to read out these sensors with enough time and temperature resolution to measure temperature changes on the cavity due to heat generated from multipacting or quenching within power pulses. The design and performance of the fast thermometry system will be discussed along with results from tests of the 9 cell 3.9GHz SRF cavity

  6. Fast thermometry for superconducting rf cavity testing

    Energy Technology Data Exchange (ETDEWEB)

    Orris, Darryl; Bellantoni, Leo; Carcagno, Ruben H.; Edwards, Helen; Harms, Elvin Robert; Khabiboulline, Timergali N.; Kotelnikov, Sergey; Makulski, Andrzej; Nehring, Roger; Pischalnikov, Yuriy; /Fermilab

    2007-06-01

    Fast readout of strategically placed low heat capacity thermometry can provide valuable information of Superconducting RF (SRF) cavity performance. Such a system has proven very effective for the development and testing of new cavity designs. Recently, several resistance temperature detectors (RTDs) were installed in key regions of interest on a new 9 cell 3.9 GHz SRF cavity with integrated HOM design at FNAL. A data acquisition system was developed to read out these sensors with enough time and temperature resolution to measure temperature changes on the cavity due to heat generated from multipacting or quenching within power pulses. The design and performance of the fast thermometry system will be discussed along with results from tests of the 9 cell 3.9GHz SRF cavity.

  7. New achievements in RF cavity manufacturing

    International Nuclear Information System (INIS)

    Lippmann, G.; Pimiskern, K.; Kaiser, H.

    1993-01-01

    Dornier has been engaged in development, manufacturing and testing of Cu-, Cu/Nb- and Nb-cavities for many years. Recently, several different types of RF cavities were manufactured. A prototype superconducting (s.c.) B-Factory accelerating cavity (1-cell, 500 MHz) was delivered to Cornell University, Laboratory of Nuclear Studies. A second lot of 6 s.c. cavities (20-cell, 3000 MHz) was fabricated on contract from Technical University of Darmstadt for the S-DALINAC facility. Finally, the first copper RF structures (9-cell, 1300 MHz) for TESLA were finished and delivered to DESY, two s.c. niobium structures of the same design are in production. Highlights from the manufacturing processes of these cavities are described and first performance results will be reported

  8. Analysis of performance limitations for superconducting cavities

    International Nuclear Information System (INIS)

    J. R. Delayen; L. R. Doolittle; C. E. Reece

    1998-01-01

    The performance of superconducting cavities in accelerators can be limited by several factors, such as: field emission, quenches, arcing, rf power; and the maximum gradient at which a cavity can operate will be determined by the lowest of these limitations for that particular cavity. The CEBAF accelerator operates with over 300 cavities and, for each of them, the authors have determined the maximum operating gradient and its limiting factor. They have developed a model that allows them to determine the distribution of gradients that could be achieved for each of these limitations independently of the others. The result of this analysis can guide an R and D program to achieve the best overall performance improvement. The same model can be used to relate the performance of single-cell and multi-cell cavities

  9. Fiber cavities with integrated mode matching optics.

    Science.gov (United States)

    Gulati, Gurpreet Kaur; Takahashi, Hiroki; Podoliak, Nina; Horak, Peter; Keller, Matthias

    2017-07-17

    In fiber based Fabry-Pérot Cavities (FFPCs), limited spatial mode matching between the cavity mode and input/output modes has been the main hindrance for many applications. We have demonstrated a versatile mode matching method for FFPCs. Our novel design employs an assembly of a graded-index and large core multimode fiber directly spliced to a single mode fiber. This all-fiber assembly transforms the propagating mode of the single mode fiber to match with the mode of a FFPC. As a result, we have measured a mode matching of 90% for a cavity length of ~400 μm. This is a significant improvement compared to conventional FFPCs coupled with just a single mode fiber, especially at long cavity lengths. Adjusting the parameters of the assembly, the fundamental cavity mode can be matched with the mode of almost any single mode fiber, making this approach highly versatile and integrable.

  10. Cavity Cooling a Single Charged Levitated Nanosphere

    Science.gov (United States)

    Millen, J.; Fonseca, P. Z. G.; Mavrogordatos, T.; Monteiro, T. S.; Barker, P. F.

    2015-03-01

    Optomechanical cavity cooling of levitated objects offers the possibility for laboratory investigation of the macroscopic quantum behavior of systems that are largely decoupled from their environment. However, experimental progress has been hindered by particle loss mechanisms, which have prevented levitation and cavity cooling in a vacuum. We overcome this problem with a new type of hybrid electro-optical trap formed from a Paul trap within a single-mode optical cavity. We demonstrate a factor of 100 cavity cooling of 400 nm diameter silica spheres trapped in vacuum. This paves the way for ground-state cooling in a smaller, higher finesse cavity, as we show that a novel feature of the hybrid trap is that the optomechanical cooling becomes actively driven by the Paul trap, even for singly charged nanospheres.

  11. Tooth structure and fracture strength of cavities

    DEFF Research Database (Denmark)

    Mondelli, José; Sene, Fábio; Ramos, Renata Pereira

    2007-01-01

    This study evaluated, in vitro, the loss of tooth substance after cavity preparation for direct and indirect restorations and its relationship with fracture strength of the prepared teeth. Sixty sound human maxillary first premolars were assigned to 6 groups (n=10). MOD direct composite cavities......) or 1/2 (Groups III and VI) of the intercuspal distance. Teeth were weighed (digital balance accurate to 0.001 g) before and after preparation to record tooth substance mass lost during cavity preparation. The prepared teeth were submitted to occlusal loading to determine their fracture strength using...... mass loss (13.91%) than composite resin preparations with the same width (10.02%). 1/2-inlay cavities had 21.34% of mass loss versus 16.19% for the 1/2-composite resin cavities. Fracture strength means (in kgf) were: GI = 187.65; GII = 143.62; GIII = 74.10; GIV = 164.22; GV = 101.92; GVI = 50...

  12. Voltage control of cavity magnon polariton

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, S., E-mail: kaurs3@myumanitoba.ca; Rao, J. W.; Gui, Y. S.; Hu, C.-M., E-mail: hu@physics.umanitoba.ca [Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada); Yao, B. M. [Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada); National Laboratory for Infrared Physics, Chinese Academy of Sciences, Shanghai 200083 (China)

    2016-07-18

    We have experimentally investigated the microwave transmission of the cavity-magnon-polariton (CMP) generated by integrating a low damping magnetic insulator onto a 2D microwave cavity. The high tunability of our planar cavity allows the cavity resonance frequency to be precisely controlled using a DC voltage. By appropriately tuning the voltage and magnetic bias, we can observe the cavity photon magnon coupling and the magnetic coupling between a magnetostatic mode and the generated CMP. The dispersion of the generated CMP was measured by either tuning the magnetic field or the applied voltage. This electrical control of CMP may open up avenues for designing advanced on-chip microwave devices that utilize light-matter interaction.

  13. Statistics of magnetoconductance in ballistic cavities

    International Nuclear Information System (INIS)

    Yang, X.; Ishio, H.; Burgdoerfer, J.

    1995-01-01

    The statistical properties of magnetoconductance in ballistic microcavities are investigated numerically. The distribution of conductance for chaotic cavities is found to follow the renormalized Porter-Thomas distribution suggested by random-matrix theory for the Gaussian ensemble while the conductance distribution of regular cavities in magnetic fields is nonuniversal and shifted towards the maximum value for a given number of open channels. The renormalized Porter-Thomas distribution implies a universal dependence of fluctuation amplitude on the mean conductance for chaotic cavities in the absence of time-reversal symmetry. The fluctuation amplitude for regular cavities is found to be larger than the saturation value of the fluctuation amplitude of chaotic cavities predicted by random-matrix theory. The change of the mean conductance as a function of the external magnetic field is consistent with semiclassical predictions

  14. Automated Hydroforming of Seamless Superconducting RF Cavity

    International Nuclear Information System (INIS)

    Nagata, Tomohiko; Shinozawa, Seiichi; Abe, Noriyuki; Nagakubo, Junki; Murakami, Hirohiko; Tajima, Tsuyoshi; Inoue, Hitoshi; Yamanaka, Masashi; Ueno, Kenji

    2012-01-01

    We are studying the possibility of automated hydroforming process for seamless superconducting RF cavities. Preliminary hydroforming tests of three-cell cavities from seamless tubes made of C1020 copper have been performed. The key point of an automated forming is to monitor and strictly control some parameters such as operation time, internal pressure and material displacements. Especially, it is necessary for our studies to be able to control axial and radial deformation independently. We plan to perform the forming in two stages to increase the reliability of successful forming. In the first stage hydroforming by using intermediate constraint dies, three-cell cavities were successfully formed in less than 1 minute. In parallel, we did elongation tests on cavity-quality niobium and confirmed that it is possible to achieve an elongation of >64% in 2 stages that is required for our forming of 1.3 GHz cavities.

  15. Culturally Relevant Cyberbullying Prevention

    OpenAIRE

    Phillips, Gregory John

    2017-01-01

    In this action research study, I, along with a student intervention committee of 14 members, developed a cyberbullying intervention for a large urban high school on the west coast. This high school contained a predominantly African American student population. I aimed to discover culturally relevant cyberbullying prevention strategies for African American students. The intervention committee selected video safety messages featuring African American actors as the most culturally relevant cyber...

  16. Design of half-reentrant SRF cavities

    International Nuclear Information System (INIS)

    Meidlinger, M.; Grimm, T.L.; Hartung, W.

    2006-01-01

    The shape of a TeSLA inner cell can be improved to lower the peak surface magnetic field at the expense of a higher peak surface electric field by making the cell reentrant. Such a single-cell cavity was designed and tested at Cornell, setting a world record accelerating gradient [V. Shemelin et al., An optimized shape cavity for TESLA: concept and fabrication, 11th Workshop on RF Superconductivity, Travemuende, Germany, September 8-12, 2003; R. Geng, H. Padamsee, Reentrant cavity and first test result, Pushing the Limits of RF Superconductivity Workshop, Argonne National Laboratory, September 22-24, 2004]. However, the disadvantage to a cavity is that liquids become trapped in the reentrant portion when it is vertically hung during high pressure rinsing. While this was overcome for Cornell's single-cell cavity by flipping it several times between high pressure rinse cycles, this may not be feasible for a multi-cell cavity. One solution to this problem is to make the cavity reentrant on only one side, leaving the opposite wall angle at six degrees for fluid drainage. This idea was first presented in 2004 [T.L. Grimm et al., IEEE Transactions on Applied Superconductivity 15(6) (2005) 2393]. Preliminary designs of two new half-reentrant (HR) inner cells have since been completed, one at a high cell-to-cell coupling of 2.1% (high-k cc HR) and the other at 1.5% (low-k cc HR). The parameters of a HR cavity are comparable to a fully reentrant cavity, with the added benefit that a HR cavity can be easily cleaned with current technology

  17. Effect of finite cavity width on flow oscillation in a low-Mach-number cavity flow

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ke; Naguib, Ahmed M. [Michigan State University, East Lansing, MI (United States)

    2011-11-15

    The current study is focused on examining the effect of the cavity width and side walls on the self-sustained oscillation in a low Mach number cavity flow with a turbulent boundary layer at separation. An axisymmetric cavity geometry is employed in order to provide a reference condition that is free from any side-wall influence, which is not possible to obtain with a rectangular cavity. The cavity could then be partially filled to form finite-width geometry. The unsteady surface pressure is measured using microphone arrays that are deployed on the cavity floor along the streamwise direction and on the downstream wall along the azimuthal direction. In addition, velocity measurements using two-component Laser Doppler Anemometer are performed simultaneously with the array measurements in different azimuthal planes. The compiled data sets are used to investigate the evolution of the coherent structures generating the pressure oscillation in the cavity using linear stochastic estimation of the velocity field based on the wall-pressure signature on the cavity end wall. The results lead to the discovery of pronounced harmonic pressure oscillations near the cavity's side walls. These oscillations, which are absent in the axisymmetric cavity, are linked to the establishment of a secondary mean streamwise circulating flow pattern near the side walls and the interaction of this secondary flow with the shear layer above the cavity. (orig.)

  18. Prototype superconducting radio-frequency cavity for LEP

    CERN Multimedia

    1985-01-01

    This niobium superconducting cavity was part of the prototype stages for an upgrade to LEP, known as LEP-2. Superconducting cavities would eventually replace the traditional copper cavities and allow beam energies of 100 GeV.

  19. Cavity-Enhanced Raman Spectroscopy for Food Chain Management

    Directory of Open Access Journals (Sweden)

    Vincenz Sandfort

    2018-02-01

    Full Text Available Comprehensive food chain management requires the monitoring of many parameters including temperature, humidity, and multiple gases. The latter is highly challenging because no low-cost technology for the simultaneous chemical analysis of multiple gaseous components currently exists. This contribution proposes the use of cavity enhanced Raman spectroscopy to enable online monitoring of all relevant components using a single laser source. A laboratory scale setup is presented and characterized in detail. Power enhancement of the pump light is achieved in an optical resonator with a Finesse exceeding 2500. A simulation for the light scattering behavior shows the influence of polarization on the spatial distribution of the Raman scattered light. The setup is also used to measure three relevant showcase gases to demonstrate the feasibility of the approach, including carbon dioxide, oxygen and ethene.

  20. Asymmetric focusing study from twin input power couplers using realistic rf cavity field maps

    Directory of Open Access Journals (Sweden)

    Colwyn Gulliford

    2011-03-01

    Full Text Available Advanced simulation codes now exist that can self-consistently solve Maxwell’s equations for the combined system of an rf cavity and a beam bunch. While these simulations are important for a complete understanding of the beam dynamics in rf cavities, they require significant time and computing power. These techniques are therefore not readily included in real time simulations useful to the beam physicist during beam operations. Thus, there exists a need for a simplified algorithm which simulates realistic cavity fields significantly faster than self-consistent codes, while still incorporating enough of the necessary physics to ensure accurate beam dynamics computation. To this end, we establish a procedure for producing realistic field maps using lossless cavity eigenmode field solvers. This algorithm incorporates all relevant cavity design and operating parameters, including beam loading from a nonrelativistic beam. The algorithm is then used to investigate the asymmetric quadrupolelike focusing produced by the input couplers of the Cornell ERL injector cavity for a variety of beam and operating parameters.

  1. The CEBAF separator cavity resonance control system

    International Nuclear Information System (INIS)

    M. Wissmann; C. Hovater; A. Guerra; T. Plawski

    2005-01-01

    The CEBAF energy upgrade will increase the maximum beam energy from 6 GeV to 12 GeV available to the experimental halls. RF deflection cavities (separators) are used to direct the electron beam to the three halls. The resulting increase in RF separator cavity gradient and subsequent increase in RF power needed for these higher energies will require the cavities to have active resonance control. Currently, at the present 4 to 6 GeV energies, the cavities are tuned mechanically and then stabilized with Low Conductivity Water (LCW) which is maintained at a constant temperature of 95 Fahrenheit. This approach is no longer feasible and an active resonance control system that controls both water temperature and flow has been designed and built. The system uses a commercial PLC with embedded PID controls to regulate water temperature and flow to the cavities. The system allows the operator to remotely adjust temperature/flow and consequently cavity resonance for the full range of beam energies. Ultimately, closed loop control will be maintained by monitoring each cavity's reflected power. This paper describes this system

  2. Present status of superconducting cavity developments

    Energy Technology Data Exchange (ETDEWEB)

    Ouchi, Nobuo; Kusano, Joichi; Hasegawa, Kazuo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment] [and others

    1997-11-01

    An R and D work of a superconducting (SC) cavity for the high intensity proton linac has begun at JAERI in collaboration with KEK. The RF field calculation and the structural analysis have been made to determine the cavity shape in the proton energy range between 100 and 1500 MeV. The results indicate the feasibility of a SC proton linac. A vertical test stand with clean room, water rinsing system, cavity evacuation pumping system, cryostat and data acquisition system has been installed to demonstrate the cavity performance. A single cell cavity of {beta}=0.5 has been fabricated and tested at the test stand to obtain the Q-value and the maximum surface electric field strength. The measured Q-values have been found to be high enough for our requirement while the field strength was limited to about 75% of the specification by the multipacting. We describe the preliminary design of the SC cavity, the overview of the vertical test stand and experimental results of the single cell cavity. (author)

  3. Superconducting cavity driving with FPGA controller

    Energy Technology Data Exchange (ETDEWEB)

    Czarski, T.; Koprek, W.; Pozniak, K.T.; Romaniuk, R.S. [Warsaw Univ. of Technology (Poland); Simrock, S.; Brand, A. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Chase, B.; Carcagno, R.; Cancelo, G. [Fermi National Accelerator Lab., Batavia, IL (United States); Koeth, T.W. [Rutgers - the State Univ. of New Jersey, NJ (United States)

    2006-07-01

    The digital control of several superconducting cavities for a linear accelerator is presented. The laboratory setup of the CHECHIA cavity and ACC1 module of the VU-FEL TTF in DESY-Hamburg have both been driven by a Field Programmable Gate Array (FPGA) based system. Additionally, a single 9-cell TESLA Superconducting cavity of the FNPL Photo Injector at FERMILAB has been remotely controlled from WUT-ISE laboratory with the support of the DESY team using the same FPGA control system. These experiments focused attention on the general recognition of the cavity features and projected control methods. An electrical model of the resonator was taken as a starting point. Calibration of the signal path is considered key in preparation for the efficient driving of a cavity. Identification of the resonator parameters has been proven to be a successful approach in achieving required performance; i.e. driving on resonance during filling and field stabilization during flattop time while requiring reasonable levels of power consumption. Feed-forward and feedback modes were successfully applied in operating the cavities. Representative results of the experiments are presented for different levels of the cavity field gradient. (orig.)

  4. Forward Modeling of a Coronal Cavity

    Science.gov (United States)

    Kucera, T. A.; Gibson, S. E.; Schmit, D. J.

    2011-01-01

    We apply a forward model of emission from a coronal cavity in an effort to determine the temperature and density distribution in the cavity. Coronal cavities are long, low-density structures located over filament neutral lines and are often seen as dark elliptical features at the solar limb in white light, EUV and X-rays. When these structures erupt they form the cavity portions of CMEs The model consists of a coronal streamer model with a tunnel-like cavity with elliptical cross-section and a Gaussian variation of height along the tunnel length. Temperature and density can be varied as a function of altitude both in the cavity and streamer. We apply this model to a cavity observed in Aug. 2007 by a wide array of instruments including Hinode/EIS, STEREO/EUVI and SOHO/EIT. Studies such as these will ultimately help us understand the the original structures which erupt to become CMEs and ICMES, one of the prime Solar Orbiter objectives.

  5. Beam tests and operation of superconducting cavities

    International Nuclear Information System (INIS)

    Akai, Kazunori

    1990-01-01

    Beam tests and operation of superconducting cavities conducted since the third workshop on RF superconductivity (Argonne, Sep. 1987) are reported in this paper. The paper is concerned particularly with electron machines. Storage and acceleration of the beam are discussed, focusing on the CERN test in SPS, the DESY test in PETRA, the superconducting injector at Darmstadt, and the KEK beam tests in T-AR. Then, long-term performance of the cavity in the ring is discussed focusing on Eacc (max) and O-value, environmental conditions, and operational experience in T-MR. RF controllability is addressed, centering on the Robinson stability, cavity tuning loop, quench detection and interlocks, recovery procedure, field calibration, and phase adjustment. Higher order modes are also discussed. Superconducting cavities have been operated successfully in accelerators. It has been confirmed that the superconducting cavities can be used stably for experimental use. For more than 5000 hours the cavities have indicated no essential degradation of the cavity performance. The study of long-term performance should be continued in longer range of period. (N.K.)

  6. Preparation and handling of superconducting RF cavities

    International Nuclear Information System (INIS)

    Furuya, Takaaki

    1990-01-01

    The present paper outlines the recent preparation methods for superconducting cavities used in various laboratories and universities, and reports the problems of the cavity fabrication at KEK as an example of mass production. Preparation and handling are first addressed, focusing on material, fabrication, surface treatment, rinsing, clean environment, and heat treatment. Cavity production at KEK is then described, centering on defects on the surface and clean environments. Field gradients of more than 20 MV/m have been obtained by 1.5-3 GHz single cavities, for multi-cell cavities Eacc of 10 MV/m are available at any frequency range. The successful construction of thirty-two cavities for TRISTAN at KEK is due to the careful checking of the surface and quality control of all processes against the surface defects and contaminations. Eacc of 5 MV/m has been achieved by 94 % of the TRISTAN cavities at the first cold test, but 6 % of them had to be reworked because of the surface defects. These defects could not be detected by an X-ray photograph or visual inspections during the fabrication processes. (N.K.)

  7. Superconducting cavity driving with FPGA controller

    International Nuclear Information System (INIS)

    Czarski, T.; Koprek, W.; Pozniak, K.T.; Romaniuk, R.S.; Simrock, S.; Brand, A.; Chase, B.; Carcagno, R.; Cancelo, G.; Koeth, T.W.

    2006-01-01

    The digital control of several superconducting cavities for a linear accelerator is presented. The laboratory setup of the CHECHIA cavity and ACC1 module of the VU-FEL TTF in DESY-Hamburg have both been driven by a Field Programmable Gate Array (FPGA) based system. Additionally, a single 9-cell TESLA Superconducting cavity of the FNPL Photo Injector at FERMILAB has been remotely controlled from WUT-ISE laboratory with the support of the DESY team using the same FPGA control system. These experiments focused attention on the general recognition of the cavity features and projected control methods. An electrical model of the resonator was taken as a starting point. Calibration of the signal path is considered key in preparation for the efficient driving of a cavity. Identification of the resonator parameters has been proven to be a successful approach in achieving required performance; i.e. driving on resonance during filling and field stabilization during flattop time while requiring reasonable levels of power consumption. Feed-forward and feedback modes were successfully applied in operating the cavities. Representative results of the experiments are presented for different levels of the cavity field gradient. (orig.)

  8. Hydroforming of Tesla Cavities at Desy

    International Nuclear Information System (INIS)

    Singer, W.; Kaiser, H.; Singer, X.; Gonin, I.; Zhelezov, I.; Khabibullin, T.; Kneisel, P.; Saito, K.

    2000-01-01

    Since several years the development of seamless niobium cavity fabrication by hydro forming is being pursued at DESY. This technique offers the possibility of lower cost of fabrication and perhaps better rf performance of the cavities because of the elimination of electron-beam welds, which in the standard fabrication technique have sometimes lead to inferior cavity performance due to defects. Several single cell 1300 MHz cavities have been formed from high purity seamless niobium tubes, which are under computer control expanded with internal pressure while simultaneously being swaged axially. The seamless tubes have been made by either back extrusion and flow forming or by spinning or deep drawing. Standard surface treatment techniques such as high temperature post purification, buffered chemical polishing (BCP), electropolishing (EP) and high pressure ultra pure water rinsing (HPR) have been applied to these cavities. The cavities exhibited high Q - values of 2 x 10 10 at 2K and residual resistances as low as 3 n(Omega) after the removal of a surface layer of app. 100 (micro)m by BCP. Surprisingly, even at high gradients up to the maximum measured values of E acc ∼ 33 MV/m the Q-value did not decrease in the absence of field emission as often observed. After electropolishing of additional 100 (micro)m one of the cavities reached an accelerating gradient of E acc (ge) 42 MV/m

  9. Predictions of laminar natural convection in heated cavities

    International Nuclear Information System (INIS)

    Winters, K.H.

    1982-06-01

    Several examples of laminar, natural convection in heated cavities are discussed with illustrative calculations. These include convection in a square cavity at high Rayleigh number; in a narrow cavity at moderate aspect ratio; in a rectangular cavity heated from below; in a trapezoidal cavity, and in a rectangular cavity containing a conducting obstruction. The steady equations for the velocity, pressure and temperature are solved in the Boussinesq approximation, using a standard Galerkin formulation of the finite-element method. (author)

  10. LEP superconducting accelerating cavity module

    CERN Multimedia

    1995-01-01

    With its 27-kilometre circumference, the Large Electron-Positron (LEP) collider was the largest electron-positron accelerator ever built. The excavation of the LEP tunnel was Europe’s largest civil-engineering project prior to the Channel Tunnel. Three tunnel-boring machines started excavating the tunnel in February 1985 and the ring was completed three years later. In its first phase of operation, LEP consisted of 5176 magnets and 128 accelerating cavities. CERN’s accelerator complex provided the particles and four enormous detectors, ALEPH, DELPHI, L3 and OPAL, observed the collisions. LEP was commissioned in July 1989 and the first beam circulated in the collider on 14 July. The collider's initial energy was chosen to be around 91 GeV, so that Z bosons could be produced. The Z boson and its charged partner the W boson, both discovered at CERN in 1983, are responsible for the weak force, which drives the Sun, for example. Observing the creation and decay of the short-lived Z boson was a critical test of...

  11. Demonstration of superconducting micromachined cavities

    Energy Technology Data Exchange (ETDEWEB)

    Brecht, T., E-mail: teresa.brecht@yale.edu; Reagor, M.; Chu, Y.; Pfaff, W.; Wang, C.; Frunzio, L.; Devoret, M. H.; Schoelkopf, R. J. [Department of Applied Physics, Yale University, New Haven, Connecticut 06511 (United States)

    2015-11-09

    Superconducting enclosures will be key components of scalable quantum computing devices based on circuit quantum electrodynamics. Within a densely integrated device, they can protect qubits from noise and serve as quantum memory units. Whether constructed by machining bulk pieces of metal or microfabricating wafers, 3D enclosures are typically assembled from two or more parts. The resulting seams potentially dissipate crossing currents and limit performance. In this letter, we present measured quality factors of superconducting cavity resonators of several materials, dimensions, and seam locations. We observe that superconducting indium can be a low-loss RF conductor and form low-loss seams. Leveraging this, we create a superconducting micromachined resonator with indium that has a quality factor of two million, despite a greatly reduced mode volume. Inter-layer coupling to this type of resonator is achieved by an aperture located under a planar transmission line. The described techniques demonstrate a proof-of-principle for multilayer microwave integrated quantum circuits for scalable quantum computing.

  12. Cancer of the oral cavity

    International Nuclear Information System (INIS)

    Wang, C.C.

    1987-01-01

    Squamous cell carcinomas of the oral cavity are curable. When early tumor (T1 and T2) is diagnosed and treated, cure rates by surgery or irradiation are high. The choice of therapeutic modalities for these lesions is complex and depends on the site of origin and size of the tumor, the presence or absence of nodal metastases, and the age, physical, medical, and socioeconomic status of the patient. Other factors include the willingness of the patient to return for a protracted course of radiation therapy, the skill of the physician, and the relative morbidity and cosmesis of the two forms of treatment. In general, surgery may be considered for early (T1) lesions if the deformity resulting from surgery is minimal. If resection involves major morbidity, such as a deformity that alters cosmesis or the function of the speech and swallowing mechanisms, then radiation therapy is preferred. For medium-sized (T2) tumors, superficial radiation therapy is the treatment of choice, for it controls the disease and preserves normal function and anatomy. Surgery is reserved for radiation failures. Extensive disease (T3 and T4) often associated with bone and muscle involvement and cervical lymph node metastases is rarely curable by radiation therapy or surgery alone; a combined approach using radiation therapy and surgery is therefore the procedure of choice

  13. Alfvenic resonant cavities in the solar atmosphere

    International Nuclear Information System (INIS)

    Hollweg, J.V.

    1984-01-01

    We investigate the propagation of Alfven waves in a simple medium consisting of three uniform layers; each layer is characterized by a different value for the Alfven speed, νsub(A). We show how the central layer can act as a resonant cavity under quite general conditions. If the cavity is driven externally, by an incident wave in one of the outer layers, there result resonant transmission peaks, which allow large energy fluxes to enter the cavity from outside. The transmission peaks result from the destructive interference between a wave which leaks out of the cavity, and a directly reflected wave. We show that there are two types of resonances. The first type occurs when the cavity has the largest (or smallest) of the three Alfven speeds; this situation occurs on coronal loops. The second type occurs when the cavity Alfven speed is intermediate between the other two values of νsub(A); this situation may occur on solar spicules. Significant heating of the cavity can occur if the waves are damped. We show that if the energy lost to heat greatly exceeds the energy lost by leakage out of the cavity, then the cavity heating can be independent of the damping rate. This conclusion is shown to apply to coronal resonances and to the spicule resonances. This conclusion agrees with a point made by Ionson in connection with the coronal resonances. Except for a numerical factor of order unity, we recover Ionson's expression for the coronal heating rate. However, Ionson's qualities are much too large. For solar parameters, the maximum quality is of the order of 100, but the heating is independent of the damping rate only when dissipation reduces the quality to less than about 10. (WB)

  14. The Limits to Relevance

    Science.gov (United States)

    Averill, M.; Briggle, A.

    2006-12-01

    Science policy and knowledge production lately have taken a pragmatic turn. Funding agencies increasingly are requiring scientists to explain the relevance of their work to society. This stems in part from mounting critiques of the "linear model" of knowledge production in which scientists operating according to their own interests or disciplinary standards are presumed to automatically produce knowledge that is of relevance outside of their narrow communities. Many contend that funded scientific research should be linked more directly to societal goals, which implies a shift in the kind of research that will be funded. While both authors support the concept of useful science, we question the exact meaning of "relevance" and the wisdom of allowing it to control research agendas. We hope to contribute to the conversation by thinking more critically about the meaning and limits of the term "relevance" and the trade-offs implicit in a narrow utilitarian approach. The paper will consider which interests tend to be privileged by an emphasis on relevance and address issues such as whose goals ought to be pursued and why, and who gets to decide. We will consider how relevance, narrowly construed, may actually limit the ultimate utility of scientific research. The paper also will reflect on the worthiness of research goals themselves and their relationship to a broader view of what it means to be human and to live in society. Just as there is more to being human than the pragmatic demands of daily life, there is more at issue with knowledge production than finding the most efficient ways to satisfy consumer preferences or fix near-term policy problems. We will conclude by calling for a balanced approach to funding research that addresses society's most pressing needs but also supports innovative research with less immediately apparent application.

  15. Relevant Subspace Clustering

    DEFF Research Database (Denmark)

    Müller, Emmanuel; Assent, Ira; Günnemann, Stephan

    2009-01-01

    Subspace clustering aims at detecting clusters in any subspace projection of a high dimensional space. As the number of possible subspace projections is exponential in the number of dimensions, the result is often tremendously large. Recent approaches fail to reduce results to relevant subspace...... clusters. Their results are typically highly redundant, i.e. many clusters are detected multiple times in several projections. In this work, we propose a novel model for relevant subspace clustering (RESCU). We present a global optimization which detects the most interesting non-redundant subspace clusters...... achieves top clustering quality while competing approaches show greatly varying performance....

  16. Upgraded cavities for the positron accumulator ring of the APS

    International Nuclear Information System (INIS)

    Kang, Y.W.; Jiang, X.; Mangra, D.

    1997-01-01

    Upgraded versions of cavities for the APS positron accumulator ring (PAR) have been built and are being tested. Two cavities are in the PAR: a fundamental 9.8-MHz cavity and a twelfth harmonic 117.3-MHz cavity. Both cavities have been manufactured for higher voltage operation with improved Q-factors, reliability, and tuning capability. Both cavities employ current-controlled ferrite tuners for control of the resonant frequency. The harmonic cavity can be operated in either a pulsed mode or a CW mode. The rf properties of the cavities are presented

  17. RF cavity evaluation with the code SUPERFISH

    International Nuclear Information System (INIS)

    Hori, T.; Nakanishi, T.; Ueda, N.

    1982-01-01

    The computer code SUPERFISH calculates axisymmetric rf fields and is most applicable to re-entrant cavities of an Alvarez linac. Some sample results are shown for the first Alvarez's in NUMATRON project. On the other hand the code can also be effectivily applied to TE modes excited in an RFQ linac when the cavity is approximately considered as positioning at an infinite distance from the symmetry axis. The evaluation was made for several RFQ cavities, models I, II and a test linac named LITL, and useful results for the resonator design were obtained. (author)

  18. Interaction of IREB with a cavity

    International Nuclear Information System (INIS)

    Sawhney, R.; Mishra, Mamta; Purkayastha, A.D.; Rambabu, P.; Maheshwari, K.P.

    1991-01-01

    The propagation of an intense pulsed relativistic electron beam (IREB) through a cavity resonator is considered. The cavity gets shock excited. The electromagnetic fields so generated interact with the beam in such a way that the energy is transferred from the front of the beam to the back. As a result the beams gets energized but shortened in time. Analysis for the chosen dominant mode of the cavity viz. TMsub(010) is carried out. The induced electric field excited is calculated and the accelerating potential is estimated. The results are compared with the recent-experiments. (author). 5 refs., 1 fig

  19. Electromagnetic Design of a Radiofrequency Cavity

    Science.gov (United States)

    Montoya Soto, G. R.; Duarte Galvan, Carlos; Monzon, Ildefonso Leon; Podesta Lerma, Pedro Luis manuel; Valerio-Lizarraga, C. A.

    2017-10-01

    Electromagnetic and mechanical studies have been performed with the aim of build a RF cavity in the S-Band (2998 MHz), the design takes into consideration the relativistic change in the electron velocity through the acceleration cavity. Four cavity cases were considered at different input energies, 50 KeV, 100 KeV, 150 KeV, with output energies of 350 KeV, the designs show good acceleration efficiency and beam coherence comparable to the one created in the cathode.

  20. The nasal cavity microbiota of healthy adults

    OpenAIRE

    Bassis, Christine M; Tang, Alice L; Young, Vincent B; Pynnonen, Melissa A

    2014-01-01

    Background The microbiota of the nares has been widely studied. However, relatively few studies have investigated the microbiota of the nasal cavity posterior to the nares. This distinct environment has the potential to contain a distinct microbiota and play an important role in health. Results We obtained 35,142 high-quality bacterial 16S rRNA-encoding gene sequence reads from the nasal cavity and oral cavity (the dorsum of the tongue and the buccal mucosa) of 12 healthy adult humans and dep...

  1. Micro-Cavity Fluidic Dye Laser

    DEFF Research Database (Denmark)

    Helbo, Bjarne; Kristensen, Anders; Menon, Aric Kumaran

    2003-01-01

    We have successfully designed, fabricated and characterized a micro-cavity fluidic dye laser with metallic mirrors, which can be integrated with polymer based lab-on-a-chip microsystems without further processing steps. A simple rate-equation model is used to predict the average pumping power...... threshold for lasing as function of cavity-mirror reflectance, laser dye concentration and cavity length. The laser device is characterized using the laser dye Rhodamine 6G dissolved in ethanol. Lasing is observed, and the influence of dye concentration is investigated....

  2. Intra-cavity vortex beam generation

    CSIR Research Space (South Africa)

    Naidoo, Darryl

    2011-08-01

    Full Text Available at exploring the methods of generating optical vortex beams. We will discuss a typical extra-cavity approach that harnesses digital holography through the use of a SLM. We consider vortex beam generation as the fundamental mode of a monolithic microchip laser...-cavity phase diffractive elements can result in the desired mode as the fundamental mode of the cavity with pure modal quality. This approach, although very attractive is insufficient for the generation of these modes in monolithic microchip lasers. A...

  3. Is Information Still Relevant?

    Science.gov (United States)

    Ma, Lia

    2013-01-01

    Introduction: The term "information" in information science does not share the characteristics of those of a nomenclature: it does not bear a generally accepted definition and it does not serve as the bases and assumptions for research studies. As the data deluge has arrived, is the concept of information still relevant for information…

  4. Radiotherapy for Oral Cavity Cancer

    International Nuclear Information System (INIS)

    Shim, Jae Won

    1993-01-01

    Eighty five patients of oral cavity cancer, treated with radiation at the Department of Therapeutic Radiology, Korea Cancer Center Hospital, during the period from March 1985 to September 1990 were analyzed retrospectively. Among 85 patients, 37 patients were treated with radiation only and 48 patients were treated with radiation following surgery And 70 patients received external irradiation only by 60 Co with or without electron, the others were 7 patients for external irradiation plus interstitial implantation and 8 patients for external irradiation plus oral cone electron therapy. Primary sites were mobile tongue for 40 patients, mouth floor for 17 patients, palate for 12 patients, gingiva including retromolar trigone for 10 patients, buccal mucosa for 5 patients, and lip for 1 patient. According to pathologic classification, squamous cell carcinoma was the most common (77 patients). According to AJC TNM stage, stage I + II were 28 patients and stage III + IV were 57 patients. Acturial overall survival rate at 3 years was 43.9%, 3 year survival rates were 60.9% for stage I + II, and 23.1% for stage III + IV, respectively. As a prognostic factor, primary T stage was a significant factor (p<0.01). The others, age, location, lymph node metastasis, surgery, radiation dose, and cell differentiation were not statistically significant. Among those factors, radiation plus surgery was more effective than radiation only in T3 + T4 or in any N stage although it was not statistically sufficient(p<0.1). From those results, it was conclusive that definitive radiotherapy was more effective than surgery especially in the view of pertaining of anatomical integrity and function in early stage, and radiation plus surgery was considered to be better therapeutic tool in advanced stage

  5. Mechanical design and fabrication of power feed cavity test setup

    International Nuclear Information System (INIS)

    Ghodke, S.R.; Dhavle, A.S.; Sharma, Vijay; Sarkar, Shreya; Kumar, Mahendra; Nayak, Susanta; Barnwal, Rajesh; Jayaprakash, D.; Mondal, J.; Nimje, V.T.; Mittal, K.C.; Gantayet, L.M.

    2013-01-01

    Power feed cavity set up consists of nine number of accelerating cavity and eight numbers of coupling cavity for testing of power feed cavity with coupling flange for 2856 MHz S band standing wave coupled cavity linac. When we are assembling the cavity and applying the pressure, its resonance frequency changes with applied pressure/load. After some critical pressure/load frequency change becomes negligible or zero. This set up will be used to find out assembly performance of power feed cavity and its coupler. Top four cavity or eight half cells as well as bottom four cavity or eight half cells will be brazed separately. Power feed cavity will be sandwiched between this two brazed cavity assemblies. This paper discuss about linear motion bush, linear motion rod, load cell, hydraulic actuator, power pack, stepper motor PLC control, jig boring, alignment, tolerances and assembly procedure for this test setup. (author)

  6. Coupled Photonic Crystal Cavity Array Laser

    DEFF Research Database (Denmark)

    Schubert, Martin

    in the quadratic lattice. Processing techniques are developed and optimized in order fabricate photonic crystals membranes in gallium arsenide with quantum dots as gain medium and in indium gallium arsenide phosphide with quantum wells as gain medium. Several key issues in process to ensure good quality....... The results are in good agreement with standard coupled mode theory. Also a novel type of photonic crystal structure is proposed called lambda shifted cavity which is a twodimensional photonic crystal laser analog of a VCSEL laser. Detailed measurements of the coupled modes in the photonic crystals...... with quantum dots are carried out. In agreement with a simple gain model the structures do not show stimulated emission. The spectral splitting due to the coupling between single cavities as well as arrays of cavities is studied theoretically and experimentally. Lasing is observed for photonic crystal cavity...

  7. Barrier Cavities in the Brookhaven AGS

    International Nuclear Information System (INIS)

    Blaskiewicz, M.; Brennan, J. M.; Roser, T.; Smith, K.; Spitz, R.; Zaltsman, A.; Fujieda, M.; Iwashita, Y.; Noda, A.; Yoshii, M.; Mori, Y.; Ohmori, C.; Sato, Y.

    1999-01-01

    In collaboration with KEK two barrier cavities, each generating 40 kV per turn have been installed in the Brookhaven AGS. Machine studies are described and their implications for high intensity operations are discussed

  8. Malignant tumors of the oral cavity

    International Nuclear Information System (INIS)

    Henk, J.M.; Langdon, J.D.

    1985-01-01

    This book discusses carcinomas of the oral cavity including the lymph nodes and salivary glands. Topics include; Epidemiology and etiology; Immunolgical and virological aspects; Basic principles of management; Surgery; Radiotherapy; Chemotherapy; and Cryosurgery

  9. Cavities produced by underground nuclear explosions

    International Nuclear Information System (INIS)

    Butkovich, T.R.

    1976-01-01

    This investigation studied the displacement of rock that formerly occupied cavities produced by underground nuclear explosions. There are three possible explanations for this displacement: the volume could be displaced to the free surface; it could occupy previously air-filled pores removed from the surrounding rock through compaction; or it could be accounted for by persisting compressive stresses induced by the outgoing shock wave. The analysis shows it unlikely that stored residual elastic stresses account for large fractions of cavity volumes. There is limited experimental evidence that free surface displacement accounts for a significant portion of this volume. Whenever the explosion mediums contain air-filled pores, the compaction of these pores most likely accounts for all the volume. Calculations show that 4 percent air-filled porosity can account for all the cavity volume within about 4 cavity radii and that even 1 percent can account for a significant fraction of the volume

  10. Cavity-enhanced spectroscopy and sensing

    Energy Technology Data Exchange (ETDEWEB)

    Gagliardi, Gianluca [CNR-Istituto Nazionale di Ottica (INO), Pozzuoli (Italy); Loock, Hans-Peter (ed.) [Queen' s Univ., Kingston, ON (Canada). Dept. of Chemistry

    2014-07-01

    The book reviews the dramatic recent advances in the use of optical resonators for high sensitivity and high resolution molecular spectroscopy as well as for chemical, mechanical and physical sensing. It encompasses a variety of cavities including those made of two or more mirrors, optical fiber loops, fiber gratings and spherical cavities. The book focuses on novel techniques and their applications. Each chapter is written by an expert and/or pioneer in the field. These experts also provide the theoretical background in optics and molecular physics where needed. Examples of recent breakthroughs include the use of frequency combs (Nobel prize 2005) for cavity enhanced sensing and spectroscopy, the use of novel cavity materials and geometries, the development of optical heterodyne detection techniques combined to active frequency-locking schemes. These methods allow the use and interrogation of optical resonators with a variety of coherent light sources for trace gas detection and sensing of strain, temperature and pressure.

  11. Cavity-enhanced spectroscopy and sensing

    CERN Document Server

    Loock, Hans-Peter

    2014-01-01

    The book reviews the dramatic recent advances in the use of optical resonators for high sensitivity and high resolution molecular spectroscopy as well as for chemical, mechanical and physical sensing.  It encompasses a variety of cavities including those made of two or more mirrors, optical fiber loops, fiber gratings and spherical cavities. The book focuses on novel techniques and their applications. Each chapter is written by an expert and/or pioneer in the field. These experts also provide the theoretical background in optics and molecular physics where needed. Examples of recent breakthroughs include the use of frequency combs (Nobel prize 2005) for cavity enhanced sensing and spectroscopy, the use of novel cavity materials and geometries, the development of optical heterodyne detection techniques combined to active frequency-locking schemes. These methods allow the use and interrogation of optical resonators with a variety of coherent light sources for trace gas detection and sensing of strain, temperat...

  12. section of an accelerating cavity from LEP

    CERN Multimedia

    This is a section of an accelerating cavity from LEP, cut in half to show the layer of niobium on the inside. Operating at 4.2 degrees above absolute zero, the niobium is superconducting and carries an accelerating field of 6 million volts per metre with negligible losses. Each cavity has a surface of 6 m2. The niobium layer is only 1.2 microns thick, ten times thinner than a hair. Such a large area had never been coated to such a high accuracy. A speck of dust could ruin the performance of the whole cavity so the work had to be done in an extremely clean environment. These challenging requirements pushed European industry to new achievements. 256 of these cavities are now used in LEP to double the energy of the particle beams.

  13. Circuit QED with 3D cavities

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Edwar; Baust, Alexander; Zhong, Ling; Gross, Rudolf [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Physik-Department, TU Muenchen, Garching (Germany); Nanosystems Initiative Munich (NIM), Muenchen (Germany); Anderson, Gustav; Wang, Lujun; Eder, Peter; Fischer, Michael; Goetz, Jan; Haeberlein, Max; Schwarz, Manuel; Wulschner, Karl Friedrich; Deppe, Frank; Fedorov, Kirill; Huebl, Hans; Menzel, Edwin [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Physik-Department, TU Muenchen, Garching (Germany); Marx, Achim [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany)

    2015-07-01

    In typical circuit QED systems on-chip superconducting qubits are coupled to integrated coplanar microwave resonators. Due to the planar geometry, the resonators are often a limiting factor regarding the total coherence of the system. Alternatively, similar hybrid systems can be realized using 3D microwave cavities. Here, we present design considerations for the 3D microwave cavity as well as the superconducting transmon qubit. Moreover, we show experimental data of a high purity aluminum cavity demonstrating quality factors above 1.4 .10{sup 6} at the single photon level and a temperature of 50 mK. Our experiments also demonstrate that the quality factor is less dependent on the power compared to planar resonator geometries. Furthermore, we present strategies for tuning both the cavity and the qubit individually.

  14. LEP superconducting cavities go into storage

    CERN Multimedia

    Patrice Loïez

    2001-01-01

    Superconducting radio-frequency cavities from the LEP-2 phase (1996-2000) are put into storage in the tunnel that once housed the Intersecting Storage Rings (ISR), the world’s first proton collider, located at CERN.

  15. Working on an LHC superconducting cavity

    CERN Multimedia

    Laurent Guiraud

    2000-01-01

    The delicate superconducting equipment for CERN’s LHC collider has to be assembled in ultra-clean conditions to safeguard performance. Here we see the power supply being installed on one of the superconducting cavities.

  16. Pulse compression by Raman induced cavity dumping

    International Nuclear Information System (INIS)

    De Rougemont, F.; Xian, D.K.; Frey, R.; Pradere, F.

    1985-01-01

    High efficiency pulse compression using Raman induced cavity dumping has been studied theoretically and experimentally. Through stimulated Raman scattering the electromagnetic energy at a primary frequency is down-converted and extracted from a storage cavity containing the Raman medium. Energy storage may be achieved either at the laser frequency by using a laser medium inside the storage cavity, or performed at a new frequency obtained through an intracavity nonlinear process. The storage cavity may be dumped passively through stimulated Raman scattering either in an oscillator or in an amplifier. All these cases have been studied by using a ruby laser as the pump source and compressed hydrogen as the Raman scatter. Results differ slightly accordingly to the technique used, but pulse shortenings higher than 10 and quantum efficiencies higher than 80% were obtained. This method could also be used with large power lasers of any wavelength from the ultraviolet to the farinfrared spectral region

  17. Hydrodynamic Drag on Streamlined Projectiles and Cavities

    KAUST Repository

    Jetly, Aditya

    2016-01-01

    The air cavity formation resulting from the water-entry of solid objects has been the subject of extensive research due to its application in various fields such as biology, marine vehicles, sports and oil and gas industries. Recently we

  18. Superconducting niobium cavities with high gradients

    International Nuclear Information System (INIS)

    Kneisel, P.; Saito, K.

    1992-01-01

    Present accelerator projects making use of superconducting cavity technology are constructed with design accelerating gradients E acc ranging between 5 MV/m and 8 MV/m and Q-values of several 10 9 . Future plans for upgrades of existing accelerators or for linear colliders call for gradients greater than 15 MV/m corresponding to peak surface electric fields above 30 MV/m. These demands challenge state-of-the-art production technology and require improvements in processing and handling of these cavities to overcome the major performance limitation of field emission loading. This paper reports on efforts to improve the performance of cavities made from niobium from different suppliers by using improved cleaning techniques after processing and ultrahigh vacuum annealing at temperatures of 1400 C. In single cell L-band cavities peak surface electric fields as high as 50 MV/m have been measured without significant field emission loading. (Author) 8 refs., fig

  19. Molding of L band niobium superconductor cavity

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Hitoshi; Funahashi, Yoshisato; Saito, Kenji; Noguchi, Shuichi; Koizumi, Susumu [National Lab. for High Energy Physics, Tsukuba, Ibaraki (Japan)

    1995-07-01

    A cavity to produce high accelerating electron field was developed. The L-band (1.3 GHz) niobium superconductor unit cell cavity was ellipsoid with {phi}217.3 mm outer diameter and 2.5 mm thickness and consisted of two pieces of half cell, two beam pipes and flange. A deep drawing process was adapted. In spite of the first trial manufacture, each good cavity was obtained. Characteristic properties of niobium materials, molding method of cavity, extension of sheet after molding, production of beam pipe, accuracy and the cost were explained. Niobium materials. showed tensile strength 15.6 kg/mm{sup 2}, load-carrying capacity 4.1 kg/mm{sup 2}, density 8.57, extension 42.5% and RRR (resistance residual ratio){>=}200. (S.Y.)

  20. WAKEFIELD DAMPING FOR THE CLIC CRAB CAVITY

    CERN Document Server

    Ambattu, P; Dexter, A; Carter, R; Khan, V; Jones, R; Dolgashev, V

    2009-01-01

    A crab cavity is required in the CLIC to allow effective head-on collision of bunches at the IP. A high operating frequency is preferred as the deflection voltage required for a given rotation angle and the RF phase tolerance for a crab cavity are inversely proportional to the operating frequency. The short bunch spacing of the CLIC scheme and the high sensitivity of the crab cavity to dipole kicks demand very high damping of the inter-bunch wakes, the major contributor to the luminosity loss of colliding bunches. This paper investigates the nature of the wakefields in the CLIC crab cavity and the possibility of using various damping schemes to suppress them effectively.

  1. Ultrasensitive and broadband magnetometry with cavity optomechanics

    DEFF Research Database (Denmark)

    Li, Bei-Bei; Bulla, Douglas; Bilek, Jan

    2017-01-01

    We achieved sensitivity of 30 pT/Hz1/2 and working bandwidth larger than 100 MHz, using cavity optomechanical magnetometry, and also demonstrated quantum light enhanced sensitivity in such a magnetometer.......We achieved sensitivity of 30 pT/Hz1/2 and working bandwidth larger than 100 MHz, using cavity optomechanical magnetometry, and also demonstrated quantum light enhanced sensitivity in such a magnetometer....

  2. Electrically Pumped Vertical-Cavity Amplifiers

    DEFF Research Database (Denmark)

    Greibe, Tine

    2007-01-01

    In this work, the design of electrically pumped vertical cavity semiconductor optical amplifiers (eVCAs) for use in a mode-locked external-cavity laser has been developed, investigated and analysed. Four different eVCAs, one top-emitting and three bottom emitting structures, have been designed...... and discussed. The thesis concludes with recommendations for further work towards the realisation of compact electrically pumped mode-locked vertical externalcavity surface emitting lasers....

  3. Ferrite measurements for SNS accelerating cavities

    International Nuclear Information System (INIS)

    Bendall, R.G.; Church, R.A.

    1979-03-01

    The RF system for the SNS has six double accelerating cavities each containing seventy ferrite toroids. Difficulties experienced in obtaining toroids to the required specifications are discussed and the two toroid test cavity built to test those supplied is described. Ferrite measurements are reported which were undertaken to measure; (a) μQf as a function of frequency and RF field level and (b) bias current as a function of frequency for different ranges of ferrite permeability μ. (U.K.)

  4. HOM power in FCC-ee cavities

    CERN Document Server

    Karpov, Ivan; Chapochnikova, Elena

    2018-01-01

    This Note summarizes the results of the power loss calculations for FCC-ee machines with 400.79 MHz cavity options. The requirements for the single-cell cavity design and for the operation with beam are obtained from the results for the high-current FCC-ee machine (Z). For other machines the power loss is sufficiently low and can be absorbed and extracted by foreseen HOM couplers.

  5. High Accelerating Field Superconducting Radio Frequency Cavities

    Science.gov (United States)

    Orr, R. S.; Saito, K.; Furuta, F.; Saeki, T.; Inoue, H.; Morozumi, Y.; Higo, T.; Higashi, Y.; Matsumoto, H.; Kazakov, S.; Yamaoka, H.; Ueno, K.; Sato, M.

    2008-06-01

    We have conducted a study of a series of single cell superconducting RF cavities at KEK. These tests were designed to investigate the effect of surface treatment on the maximum accelerating field attainable. All of these cavities are of the ICHIRO shape, based on the Low Loss shape. Our results indicate that accelerating fields as high as the theoretical maximum of 50MV/m are attainable.

  6. Cellular automata in photonic cavity arrays.

    Science.gov (United States)

    Li, Jing; Liew, T C H

    2016-10-31

    We propose theoretically a photonic Turing machine based on cellular automata in arrays of nonlinear cavities coupled with artificial gauge fields. The state of the system is recorded making use of the bistability of driven cavities, in which losses are fully compensated by an external continuous drive. The sequential update of the automaton layers is achieved automatically, by the local switching of bistable states, without requiring any additional synchronization or temporal control.

  7. Resonance control in SRF cavities at FNAL

    Energy Technology Data Exchange (ETDEWEB)

    Schappert, W.; Pischalnikov, Y.; /Fermilab; Scorrano, M.; /INFN, Pisa

    2011-03-01

    The Lorentz force can dynamically detune pulsed Superconducting RF cavities. Considerable additional RF power can be required to maintain the accelerating gradient if no effort is made to compensate for this detuning. Compensation systems using piezo actuators have been used successfully at DESY and elsewhere to control Lorentz Force Detuning (LFD). Recently, Fermilab has developed an adaptive compensation system for cavities in the Horizontal Test Stand, in the SRF Accelerator Test Facility, and for the proposed Project X.

  8. Performance experience with the CEBAF SRF cavities

    International Nuclear Information System (INIS)

    Reece, C.; Benesch, J.; Drury, M.; Hovater, C.; Mammosser, J.; Preble, J.

    1995-01-01

    The full complement of 169 pairs of niobium superconducting cavities has been installed in the CEBAF accelerator. This paper surveys the performance characteristics of these cavities in vertical tests, commissioning in the tunnel, and operational experience to date. Although installed performance exceeds specifications, and 3.2 GeV beam has been delivered on target, present systems do not consistently preserve the high performance obtained in vertical dewar tests as operational capability. Principal sources of these limitations are discussed

  9. Early 500 MHz prototype LEP RF Cavity with superposed storage cavity

    CERN Multimedia

    CERN PhotoLab

    1981-01-01

    The principle of transferring the RF power back and forth between the accelerating cavity and a side-coupled storage cavity was demonstrated with this 500 MHz prototype. In LEP, the accelerating frequency was 352.2 MHz, and accelerating and storage cavities were consequently larger. See also 8002294, 8006061, 8407619X, and Annual Reports 1980, p.115; 1981, p.95; 1985, vol.I, p.13.

  10. The CEBAF Separator Cavity Resonance Control System

    CERN Document Server

    Wissmann, Mark J; Hovater, Curt; Plawski, Tomasz

    2005-01-01

    The CEBAF energy upgrade from 6 GeV to 12GeV will increase the range of beam energies available to the experimental halls. RF deflection cavities (separators) are used to direct the electron beam to the three experimental halls. Consequently with the increase in RF separator cavity gradient needed for the higher energies, RF power will also increase requiring the cavities to have active resonance control. At the 6 GeV energy, the cavities are tuned mechanically and then stabilized with Low Conductivity Water (LCW), which is maintained at constant temperature of 95o Fahrenheit. This is no longer feasible and an active resonance control system, that controls both water temperature and flow has been built. The system uses a commercial PLC with embedded PID controls to control water temperature and flow to the cavities. The system allows the operator to remotely adjust temperature/flow and consequently cavity resonance for the full range of beam energies. Ultimately closed loop control will be maintained by monit...

  11. Study of CSR longitudinal bunch compression cavity

    International Nuclear Information System (INIS)

    Yin Dayu; Li Peng; Liu Yong; Xie Qingchun

    2009-01-01

    The scheme of longitudinal bunch compression cavity for the Cooling Storage Ring (CSR)is an important issue. Plasma physics experiments require high density heavy ion beam and short pulsed bunch,which can be produced by non-adiabatic compression of bunch implemented by a fast compression with 90 degree rotation in the longitudinal phase space. The phase space rotation in fast compression is initiated by a fast jump of the RF-voltage amplitude. For this purpose, the CSR longitudinal bunch compression cavity, loaded with FINEMET-FT-1M is studied and simulated with MAFIA code. In this paper, the CSR longitudinal bunch compression cavity is simulated and the initial bunch length of 238 U 72+ with 250 MeV/u will be compressed from 200 ns to 50 ns.The construction and RF properties of the CSR longitudinal bunch compression cavity are simulated and calculated also with MAFIA code. The operation frequency of the cavity is 1.15 MHz with peak voltage of 80 kV, and the cavity can be used to compress heavy ions in the CSR. (authors)

  12. Superconducting rf and beam-cavity interactions

    International Nuclear Information System (INIS)

    Bisognano, J.J.

    1987-01-01

    Beam-cavity interactions can limit the beam quality and current handling capability of linear and circular accelerators. These collective effects include cumulative and regenerative transverse beam breakup (BBU) in linacs, transverse multipass beam breakup in recirculating linacs and microtrons, longitudinal and transverse coupled-bunch instabilities in storage rings, and a variety of transverse and longitudinal single-bunch phenomena (instabilities, beam breakup, and energy deposition). The superconducting radio frequency (SRF) environment has a number of features which distinguish it from room temperature configuration with regard to these beam-cavity interactions. Typically the unloaded Qs of the lower higher order modes (HOM) are at the 10 9 level and require significant damping through couplers. High gradient CW operation, which is a principal advantage of SRF, allows for better control of beam quality, which for its preservation requires added care which respect to collective phenomena. Gradients are significantly higher than those attainable with copper in CW operation but remain significantly lower than those obtainable with pulsed copper cavities. Finally, energy deposition by the beam into the cavity can occur in a cryogenic environment. In this note those characteristics of beam-cavity interactions which are of particular importance for superconducting RF cavities are highlighted. 6 refs., 4 figs

  13. Beam induced rf cavity transient voltage

    International Nuclear Information System (INIS)

    Kramer, S.L.; Wang, J.M.

    1998-10-01

    The authors calculate the transient voltage induced in a radio frequency cavity by the injection of a relativistic bunched beam into a circular accelerator. A simplified model of the beam induced voltage, using a single tone current signal, is generated and compared with the voltage induced by a more realistic model of a point-like bunched beam. The high Q limit of the bunched beam model is shown to be related simply to the simplified model. Both models are shown to induce voltages at the resonant frequency ω r of the cavity and at an integer multiple of the bunch revolution frequency (i.e. the accelerating frequency for powered cavity operation) hω ο . The presence of two nearby frequencies in the cavity leads to a modulation of the carrier wave exp(hω ο t). A special emphasis is placed in this paper on studying the modulation function. These models prove useful for computing the transient voltage induced in superconducting rf cavities, which was the motivation behind this research. The modulation of the transient cavity voltage discussed in this paper is the physical basis of the recently observed and explained new kinds of longitudinal rigid dipole mode which differs from the conventional Robinson mode

  14. Clinical Relevance of Adipokines

    Directory of Open Access Journals (Sweden)

    Matthias Blüher

    2012-10-01

    Full Text Available The incidence of obesity has increased dramatically during recent decades. Obesity increases the risk for metabolic and cardiovascular diseases and may therefore contribute to premature death. With increasing fat mass, secretion of adipose tissue derived bioactive molecules (adipokines changes towards a pro-inflammatory, diabetogenic and atherogenic pattern. Adipokines are involved in the regulation of appetite and satiety, energy expenditure, activity, endothelial function, hemostasis, blood pressure, insulin sensitivity, energy metabolism in insulin sensitive tissues, adipogenesis, fat distribution and insulin secretion in pancreatic β-cells. Therefore, adipokines are clinically relevant as biomarkers for fat distribution, adipose tissue function, liver fat content, insulin sensitivity, chronic inflammation and have the potential for future pharmacological treatment strategies for obesity and its related diseases. This review focuses on the clinical relevance of selected adipokines as markers or predictors of obesity related diseases and as potential therapeutic tools or targets in metabolic and cardiovascular diseases.

  15. Information Needs/Relevance

    OpenAIRE

    Wildemuth, Barbara M.

    2009-01-01

    A user's interaction with a DL is often initiated as the result of the user experiencing an information need of some kind. Aspects of that experience and how it might affect the user's interactions with the DL are discussed in this module. In addition, users continuously make decisions about and evaluations of the materials retrieved from a DL, relative to their information needs. Relevance judgments, and their relationship to the user's information needs, are discussed in this module. Draft

  16. Paramagnetism and diamagnetism in EXTRAP

    International Nuclear Information System (INIS)

    Tennfors, E.

    1991-10-01

    Magnetic field profiles measured in Extrap discharges with an imposed axial/toroidal magnetic field are analysed in the present article. In a linear device, Extrap L1, the axial current is driven by an applied electrode voltage. In the toroidal Extrap T1, the toroidal current is induced. Contributions to the current, and addition to that due to the applied voltage, may arise from radial diffusion as well as from dynamo effects like those observed in reversed field pinches. Typical magnetic field profiles are studied here in order to assess these contributions. (12 refs., 14 figs.)

  17. Diamagnetism in quasicrystalline superconducting networks

    International Nuclear Information System (INIS)

    Qian Niu; Nori, F.

    1990-01-01

    In this paper, we review recent results on superconducting structures with quasicrystalline geometry. Specifically, we consider the superconducting-normal phase boundaries of a variety of wire networks and Josephson junction arrays. We have computed the mean field phase diagrams for a number of geometries and compared them to the corresponding experimental data. We have introduced an analytical approach to the analysis of the structures present in the phase boundaries. Furthermore, we have shown in great detail how the gross structure is determined by the statistical distributions of the cell areas, and how the fine structures are determined by correlations among neighboring cells in the lattices. (author). 12 refs, 2 figs

  18. Universal fluctuations in orbital diamagnetism

    Indian Academy of Sciences (India)

    P S Pal

    published online 31 January 2018. Abstract. Bohr–van ... friction and (c) particle moving in a medium with space-dependent temperature. For all the three cases, the average ..... A M J thanks Department of Science and Technology,. India, for ...

  19. Estimating tree cavity distributions from historical FIA data

    Science.gov (United States)

    Mark D. Nelson; Charlotte. Roy

    2012-01-01

    Tree cavities provide important habitat features for a variety of wildlife species. We describe an approach for using historical FIA data to estimate the number of trees containing cavities during the 1990s in seven states of the Upper Midwest. We estimated a total of 280 million cavity-containing trees. Iowa and Missouri had the highest percentages of cavity-...

  20. Teleportation of atomic states with a weak coherent cavity field

    Institute of Scientific and Technical Information of China (English)

    Zheng Shi-Biao

    2005-01-01

    A scheme is proposed for the teleportation of an unknown atomic state. The scheme is based on the resonant interaction of atoms with a coherent cavity field. The mean photon-number of the cavity field is much smaller than one and thus the cavity decay can be effectively suppressed. Another adwntage of the scheme is that only one cavity is required.

  1. Probing exotic phenomena at the interface of nuclear and particle physics with the electric dipole moments of diamagnetic atoms: A unique window to hadronic and semi-leptonic CP violation

    Energy Technology Data Exchange (ETDEWEB)

    Yamanaka, N. [RIKEN, Wako, iTHES Research Group, Saitama (Japan); Far Eastern Federal University, Complex Simulation Group, School of Biomedicine, Vladivostok (Russian Federation); Sahoo, B.K. [Physical Research Laboratory, Atomic, Molecular and Optical Physics Division, Ahmedabad (India); Yoshinaga, N. [Graduate School of Science and Engineering, Saitama (Japan); Sato, T. [RIKEN, Nishina Center, Saitama (Japan); Asahi, K. [RIKEN, Nishina Center, Saitama (Japan); Tokyo Institute of Technology, Department of Physics and International Education and Research Center of Science, Tokyo (Japan); Das, B.P. [Tokyo Institute of Technology, Department of Physics and International Education and Research Center of Science, Tokyo (Japan)

    2017-03-15

    The current status of electric dipole moments of diamagnetic atoms which involves the synergy between atomic experiments and three different theoretical areas, i.e. particle, nuclear and atomic, is reviewed. Various models of particle physics that predict CP violation, which is necessary for the existence of such electric dipole moments, are presented. These include the standard model of particle physics and various extensions of it. Effective hadron level combined charge conjugation (C) and parity (P) symmetry violating interactions are derived taking into consideration different ways in which a nucleon interacts with other nucleons as well as with electrons. Nuclear structure calculations of the CP-odd nuclear Schiff moment are discussed using the shell model and other theoretical approaches. Results of the calculations of atomic electric dipole moments due to the interaction of the nuclear Schiff moment with the electrons and the P and time-reversal (T) symmetry violating tensor-pseudotensor electron-nucleus are elucidated using different relativistic many-body theories. The principles of the measurement of the electric dipole moments of diamagnetic atoms are outlined. Upper limits for the nuclear Schiff moment and tensor-pseudotensor coupling constant are obtained combining the results of atomic experiments and relativistic many-body theories. The coefficients for the different sources of CP violation have been estimated at the elementary particle level for all the diamagnetic atoms of current experimental interest and their implications for physics beyond the standard model is discussed. Possible improvements of the current results of the measurements as well as quantum chromodynamics, nuclear and atomic calculations are suggested. (orig.)

  2. Optimization of Helium Vessel Design for ILC Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Fratangelo, Enrico [Univ. of Pisa (Italy)

    2009-01-01

    certify the compliance of the Helium vessel and the cavity to the ASME code standard. After briefly recalling to the main contents of the the ASME Code (Sections II and Vlll - Division ll), the procedure used for finding all relevant stresses and comparing the obtained results with the maximum values allowed are explained. This part also includes the buckling verification of the cavity. In Chapter 5 the manufacturing process of the cavity end-caps, whose function is to link the Helium vessel with the cavity, is studied. The present configuration of the dies is described and the manufacturing process is simulated in order to explain the origin of some defects fol.llld on real parts. Finally a new design of the dies is proposed and the resulting deformed piece is compared with the design requirements. Chapter 6 describes a finite elements analysis to assess the efficiency and the stiffness of the Helium vessel. Furthermore the results of the optimization of the Helium vessel (in order to increase the value of the efficiency) are reported. The same stiffness analysis is used in Chapter 7 for the Blade-Tuner study. After a description of this tuner and of its function, the preliminary analyses done to confirm the results provided by the vendor are described and then its limiting load conditions are found. Chapter 8 shows a study of the resistance of all the welds present in between the cavity and the end-cap and between the end-caps and the He vessel for a smaller superconducting cavity operating at 3.9 GHz. Finally Chapter 9 briefly describes some R&D activities in progress at INFN (Section of Pisa) and Fermilab that could produce significant cost reductions of the Helium vessel design. All the finite elements analyses contained and described in this thesis made possible the certification of the whole superconducting cavity-Helium vessel assembly at Fermilab. Furthermore they gave several useful indications to the Fermilab staff to improve the performance of the Helium

  3. RF BREAKDOWN STUDIES USING PRESSURIZED CAVITIES

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Rolland

    2014-09-21

    Many present and future particle accelerators are limited by the maximum electric gradient and peak surface fields that can be realized in RF cavities. Despite considerable effort, a comprehensive theory of RF breakdown has not been achieved and mitigation techniques to improve practical maximum accelerating gradients have had only limited success. Part of the problem is that RF breakdown in an evacuated cavity involves a complex mixture of effects, which include the geometry, metallurgy, and surface preparation of the accelerating structures and the make-up and pressure of the residual gas in which plasmas form. Studies showed that high gradients can be achieved quickly in 805 MHz RF cavities pressurized with dense hydrogen gas, as needed for muon cooling channels, without the need for long conditioning times, even in the presence of strong external magnetic fields. This positive result was expected because the dense gas can practically eliminate dark currents and multipacting. In this project we used this high pressure technique to suppress effects of residual vacuum and geometry that are found in evacuated cavities in order to isolate and study the role of the metallic surfaces in RF cavity breakdown as a function of magnetic field, frequency, and surface preparation. One of the interesting and useful outcomes of this project was the unanticipated collaborations with LANL and Fermilab that led to new insights as to the operation of evacuated normal-conducting RF cavities in high external magnetic fields. Other accomplishments included: (1) RF breakdown experiments to test the effects of SF6 dopant in H2 and He gases with Sn, Al, and Cu electrodes were carried out in an 805 MHz cavity and compared to calculations and computer simulations. The heavy corrosion caused by the SF6 components led to the suggestion that a small admixture of oxygen, instead of SF6, to the hydrogen would allow the same advantages without the corrosion in a practical muon beam line. (2) A

  4. Radiation measurements during cavities conditioning on APS RF test stand

    International Nuclear Information System (INIS)

    Grudzien, D.M.; Kustom, R.L.; Moe, H.J.; Song, J.J.

    1993-01-01

    In order to determine the shielding structure around the Advanced Photon Source (APS) synchrotron and storage ring RF stations, the X-ray radiation has been measured in the near field and far field regions of the RF cavities during the normal conditioning process. Two cavity types, a prototype 352-MHz single-cell cavity and a 352-MHz five-cell cavity, are used on the APS and are conditioned in the RF test stand. Vacuum measurements are also taken on a prototype 352-MHz single-cell cavity and a 352-MHz five-cell cavity. The data will be compared with data on the five-cell cavities from CERN

  5. JLab SRF Cavity Fabrication Errors, Consequences and Lessons Learned

    International Nuclear Information System (INIS)

    Marhauser, Frank

    2011-01-01

    Today, elliptical superconducting RF (SRF) cavities are preferably made from deep-drawn niobium sheets as pursued at Jefferson Laboratory (JLab). The fabrication of a cavity incorporates various cavity cell machining, trimming and electron beam welding (EBW) steps as well as surface chemistry that add to forming errors creating geometrical deviations of the cavity shape from its design. An analysis of in-house built cavities over the last years revealed significant errors in cavity production. Past fabrication flaws are described and lessons learned applied successfully to the most recent in-house series production of multi-cell cavities.

  6. High field conditioning of cryogenic RF cavities

    International Nuclear Information System (INIS)

    Cole, M.; Debiak, T.; Lom, C.; Shephard, W.; Sredniawski, J.

    1993-01-01

    Space-based and other related accelerators have conditioning and operation requirements that are not found in most machines. The use of cryogenic copper, relatively poor vacuum, and limited power storage and operating time put unusual demands on the high-field conditioning process and present some concerns. Two CW cryogenic engineering model open-quotes sparkerclose quotes cavities have been fabricated and tested to fairly high field levels. Tests included initial and repeated conditioning as well as sustained RF operations. The two cavities were an engineering model TDL and an engineering model RFQ. Both cavities operated at 425 MHz. The DTL was conditioned to 46 MV/m at 100% duty factor (CW) at cryogenic temperature. This corresponds to a gap voltage of 433 kV and a real estate accelerating gradient (energy gain/total cavity length) of 6.97 MV/m. The authors believe this to be record performance for cryo CW operation. During cryo pulsed operation, the same cavity reached 48 MV/m with 200 μsec pulses at 0.5% DF. The RFQ was conditioned to 30 MV/m CW at cryo, 85 kV gap voltage. During a brief period of cryo pulsed operation, the RFQ operated at 46 MV/m, or 125 kV gap voltage. Reconditioning experiments were performed on both cavities and no problems were encountered. It should be noted that the vacuum levels were not very stringent during these tests and no special cleanliness or handling procedures were followed. The results of these tests indicate that cavities can run CW without difficulty at cryogenic temperatures at normal conservative field levels. Higher field operation may well be possible, and if better vacuums are used and more attention is paid to cleanliness, much higher fields may be attainable

  7. Superconducting cavity material for the European XFEL

    Science.gov (United States)

    Singer, W.; Singer, X.; Brinkmann, A.; Iversen, J.; Matheisen, A.; Navitski, A.; Tamashevich, Y.; Michelato, P.; Monaco, L.

    2015-08-01

    Analysis of the strategy for superconducting cavity material procurement and quality management is done on the basis of the experience with the cavity production for the European x-ray free electron laser (EXFEL) facility. An adjustment of the material specification to EXFEL requirements, procurement of material, quality control (QC), documentation, and shipment to cavity producers have been worked out and carried out by DESY. A multistep process of qualification of the material suppliers included detailed material testing, single- and nine-cell cavity fabrication, and cryogenic radiofrequency tests. Production of about 25 000 semi-finished parts of high purity niobium and niobium-titanium alloy in a period of three years has been divided finally between companies Heraeus, Tokyo Denkai, Ningxia OTIC, and PLANSEE. Consideration of large-grain (LG) material as a possible option for the EXFEL has resulted in the production of one cryogenic module consisting of seven (out of eight) LG cavities. LG materials fulfilled the EXFEL requirements and showed even 25% to 30% higher unloaded quality factor. A possible shortage of the required quantity of LG material on the market led, however, to the choice of conventional fine-grain (FG) material. Eddy-current scanning (ECS) has been applied as an additional QC tool for the niobium sheets and contributed significantly to the material qualification and sorting. Two percent of the sheets have been rejected, which potentially could affect up to one-third of the cavities. The main imperfections and defects in the rejected sheets have been analyzed. Samples containing foreign material inclusions have been extracted from the sheets and electrochemically polished. Some inclusions remained even after 150 μm surface layer removal. Indications of foreign material inclusions have been found in the industrially fabricated and treated cavities and a deeper analysis of the defects has been performed.

  8. Development of the L-band superconducting cavity system

    Energy Technology Data Exchange (ETDEWEB)

    Ota, T.; Kakutani, N.; Sukenobu, S. [Toshiba Corp., Yokohama, Kanagawa (JP)] [and others

    2000-02-01

    R and D activities on superconducting cavities in 1998 at TOSHIBA are presented. An L-band single-cell niobium cavity with four ports on the beam pipes was fabricated in our company and tested at KEK. The cryostat and refrigerator system for the cavity were designed and fabricated. The cryostat installed the cavity was tested in low temperature. R and D of hydroforming to fabricate seamless cavities is also presented. (author)

  9. Development of the L-band superconducting cavity system

    International Nuclear Information System (INIS)

    Ota, T.; Kakutani, N.; Sukenobu, S.

    2000-01-01

    R and D activities on superconducting cavities in 1998 at TOSHIBA are presented. An L-band single-cell niobium cavity with four ports on the beam pipes was fabricated in our company and tested at KEK. The cryostat and refrigerator system for the cavity were designed and fabricated. The cryostat installed the cavity was tested in low temperature. R and D of hydroforming to fabricate seamless cavities is also presented. (author)

  10. Discrete vapour cavity model with improved timing of opening and collapse of cavities

    NARCIS (Netherlands)

    Bergant, A.; Tijsseling, A.S.; Vítkovský, J.P.; Simpson, A.R.; Lambert, M.F.

    2007-01-01

    Transient vaporous cavitation occurs in hydraulic piping systems when the liquid pressure falls to the vapour pressure. Cavitation may occur as a localized vapour cavity (large void fraction) or as distributed vaporous cavitation (small void fraction). The discrete vapour cavity model (DVCM) with

  11. Natural cavity characteristics and cavity bird abundance on West Virginia forested islands of the Ohio River

    Science.gov (United States)

    James T. Anderson; Karen A. Riesz

    2013-01-01

    Wildlife habitats connected with forested islands and their back channels (areas where commercial traffic is prohibited) on the Ohio River are valuable to diverse species. However, quantitative data on the importance of these areas to cavity-nesting birds are lacking. We compared cavity-nesting bird use and habitat between back and navigational channel sides of islands...

  12. Offline estimation of decay time for an optical cavity with a low pass filter cavity model.

    Science.gov (United States)

    Kallapur, Abhijit G; Boyson, Toby K; Petersen, Ian R; Harb, Charles C

    2012-08-01

    This Letter presents offline estimation results for the decay-time constant for an experimental Fabry-Perot optical cavity for cavity ring-down spectroscopy (CRDS). The cavity dynamics are modeled in terms of a low pass filter (LPF) with unity DC gain. This model is used by an extended Kalman filter (EKF) along with the recorded light intensity at the output of the cavity in order to estimate the decay-time constant. The estimation results using the LPF cavity model are compared to those obtained using the quadrature model for the cavity presented in previous work by Kallapur et al. The estimation process derived using the LPF model comprises two states as opposed to three states in the quadrature model. When considering the EKF, this means propagating two states and a (2×2) covariance matrix using the LPF model, as opposed to propagating three states and a (3×3) covariance matrix using the quadrature model. This gives the former model a computational advantage over the latter and leads to faster execution times for the corresponding EKF. It is shown in this Letter that the LPF model for the cavity with two filter states is computationally more efficient, converges faster, and is hence a more suitable method than the three-state quadrature model presented in previous work for real-time estimation of the decay-time constant for the cavity.

  13. [Relevant public health enteropathogens].

    Science.gov (United States)

    Riveros, Maribel; Ochoa, Theresa J

    2015-01-01

    Diarrhea remains the third leading cause of death in children under five years, despite recent advances in the management and prevention of this disease. It is caused by multiple pathogens, however, the prevalence of each varies by age group, geographical area and the scenario where cases (community vs hospital) are recorded. The most relevant pathogens in public health are those associated with the highest burden of disease, severity, complications and mortality. In our country, norovirus, Campylobacter and diarrheagenic E. coli are the most prevalent pathogens at the community level in children. In this paper we review the local epidemiology and potential areas of development in five selected pathogens: rotavirus, norovirus, Shiga toxin-producing E. coli (STEC), Shigella and Salmonella. Of these, rotavirus is the most important in the pediatric population and the main agent responsible for child mortality from diarrhea. The introduction of rotavirus vaccination in Peru will have a significant impact on disease burden and mortality from diarrhea. However, surveillance studies are needed to determine the impact of vaccination and changes in the epidemiology of diarrhea in Peru following the introduction of new vaccines, as well as antibiotic resistance surveillance of clinical relevant bacteria.

  14. CT findings of malignant nasal cavity tumors

    International Nuclear Information System (INIS)

    Ku, Young Mi; Chun, Kyung Ah; Choi, Kyu Ho; Yu, Won Jong; Kim, Young Joo; Kim, Sung Hoon; Park, Seog Hee; Shinn, Kyung Sub

    1997-01-01

    To evaluate the CT findings of malignant nasal cavity tumors. Retrospective analysis was performed on 20 patients with pathologically-proven malignant nasal cavity tumors. Using CT, we analysed their location, extent of bone destruction and of involvement of adjacent structures, and enhancing pattern. A total of 20 cases included nine squamous cell carcinomas, three olfactory neuroblastomas, three lymphomas, two polymorphic reticulosis, one adenoid cystic carcinoma, one undifferentiated carcinoma and one metastasis from renal cell carcinoma. All cases except one adenoid cystic carcinoma and one squamous cell carcinoma revealed bone destruction or erosion. Aggressive bone destruction and irregular enhancement were seen in eight cases of squamous cell carcinoma, seven cases of which showed involvement of the adjacent paranasal sinuses, nasopharynx, and orbit. Olfactory neuroblastomas were centered in the superior nasal cavity and the adjacent ethmoid sinus, and erosion or destruction of the cribriform plate had occurred. Lymphomas showed bilateral involvement, with uniform contrast enhancement. Polymorphic reticuloses showed perforation or erosion of the nasal septum, with bilateral involvement of the nasal cavity. The location, presence of bone destruction, involvement of adjacent structures, and enhancement pattern of tumor on CT can be helpful for the differential diagnosis of malignant nasal cavity tumors

  15. Multi-Mode Cavity Accelerator Structure

    International Nuclear Information System (INIS)

    Jiang, Yong; Hirshfield, Jay Leonard

    2016-01-01

    This project aimed to develop a prototype for a novel accelerator structure comprising coupled cavities that are tuned to support modes with harmonically-related eigenfrequencies, with the goal of reaching an acceleration gradient >200 MeV/m and a breakdown rate <10"-"7/pulse/meter. Phase I involved computations, design, and preliminary engineering of a prototype multi-harmonic cavity accelerator structure; plus tests of a bimodal cavity. A computational procedure was used to design an optimized profile for a bimodal cavity with high shunt impedance and low surface fields to maximize the reduction in temperature rise Δ T. This cavity supports the TM010 mode and its 2nd harmonic TM011 mode. Its fundamental frequency is at 12 GHz, to benchmark against the empirical criteria proposed within the worldwide High Gradient collaboration for X-band copper structures; namely, a surface electric field E_s_u_r"m"a"x< 260 MV/m and pulsed surface heating Δ T"m"a"x< 56 °K. With optimized geometry, amplitude and relative phase of the two modes, reductions are found in surface pulsed heating, modified Poynting vector, and total RF power - as compared with operation at the same acceleration gradient using only the fundamental mode.

  16. Multi-Mode Cavity Accelerator Structure

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Yong [Yale Univ., New Haven, CT (United States); Hirshfield, Jay Leonard [Omega-P R& D, Inc., New Haven, CT (United States)

    2016-11-10

    This project aimed to develop a prototype for a novel accelerator structure comprising coupled cavities that are tuned to support modes with harmonically-related eigenfrequencies, with the goal of reaching an acceleration gradient >200 MeV/m and a breakdown rate <10-7/pulse/meter. Phase I involved computations, design, and preliminary engineering of a prototype multi-harmonic cavity accelerator structure; plus tests of a bimodal cavity. A computational procedure was used to design an optimized profile for a bimodal cavity with high shunt impedance and low surface fields to maximize the reduction in temperature rise ΔT. This cavity supports the TM010 mode and its 2nd harmonic TM011 mode. Its fundamental frequency is at 12 GHz, to benchmark against the empirical criteria proposed within the worldwide High Gradient collaboration for X-band copper structures; namely, a surface electric field Esurmax< 260 MV/m and pulsed surface heating ΔTmax< 56 °K. With optimized geometry, amplitude and relative phase of the two modes, reductions are found in surface pulsed heating, modified Poynting vector, and total RF power—as compared with operation at the same acceleration gradient using only the fundamental mode.

  17. Cavity electromagnetically induced transparency with Rydberg atoms

    Science.gov (United States)

    Bakar Ali, Abu; Ziauddin

    2018-02-01

    Cavity electromagnetically induced transparency (EIT) is revisited via the input probe field intensity. A strongly interacting Rydberg atomic medium ensemble is considered in a cavity, where atoms behave as superatoms (SAs) under the dipole blockade mechanism. Each atom in the strongly interacting Rydberg atomic medium (87 Rb) follows a three-level cascade atomic configuration. A strong control and weak probe field are employed in the cavity with the ensemble of Rydberg atoms. The features of the reflected and transmitted probe light are studied under the influence of the input probe field intensity. A transparency peak (cavity EIT) is revealed at a resonance condition for small values of input probe field intensity. The manipulation of the cavity EIT is reported by tuning the strength of the input probe field intensity. Further, the phase and group delay of the transmitted and reflected probe light are studied. It is found that group delay and phase in the reflected light are negative, while for the transmitted light they are positive. The magnitude control of group delay in the transmitted and reflected light is investigated via the input probe field intensity.

  18. Effect of low temperature baking on the RF properties of niobium superconducting cavities for particle accelerators

    International Nuclear Information System (INIS)

    Gianluigi Ciovati

    2004-01-01

    Radio-frequency superconducting (SRF) cavities are widely used to accelerate a charged particle beam in particle accelerators. The performance of SRF cavities made of bulk niobium has significantly improved over the last ten years and is approaching the theoretical limit for niobium. Nevertheless, RF tests of niobium cavities are still showing some ''anomalous'' losses that require a better understanding in order to reliably obtain better performance. These losses are characterized by a marked dependence of the surface resistance on the surface electromagnetic field and can be detected by measuring the quality factor of the resonator as a function of the peak surface field. A low temperature (100 C-150 C) ''in situ'' bake under ultra-high vacuum has been successfully applied as final preparation of niobium RF cavities by several laboratories over the last few years. The benefits reported consist mainly of an improvement of the cavity quality factor at low field and a recovery from ''anomalous'' losses (so-called ''Q-drop'') without field emission at higher field. A series of experiments with a CEBAF single-cell cavity have been carried out at Jefferson Lab to carefully investigate the effect of baking at progressively higher temperatures for a fixed time on all the relevant material parameters. Measurements of the cavity quality factor in the temperature range 1.37 K-280 K and resonant frequency shift between 6 K-9.3 K provide information about the surface resistance, energy gap, penetration depth and mean free path. The experimental data have been analyzed with the complete BCS theory of superconductivity. The hydrogen content of small niobium samples inserted in the cavity during its surface preparation was analyzed with Nuclear Reaction Analysis (NRA). The single-cell cavity has been tested at three different temperatures before and after baking to gain some insight on thermal conductivity and Kapitza resistance and the data are compared with different models

  19. Scheme for the implementation of a universal quantum cloning machine via cavity-assisted atomic collisions in cavity QED

    International Nuclear Information System (INIS)

    Zou Xubo; Pahlke, K.; Mathis, W.

    2003-01-01

    We propose a scheme to implement the 1→2 universal quantum cloning machine of Buzek and Hillery [Phys. Rev. A 54, 1844 (1996)] in the context of cavity QED. The scheme requires cavity-assisted collision processes between atoms, which cross through nonresonant cavity fields in the vacuum states. The cavity fields are only virtually excited to face the decoherence problem. That's why the requirements on the cavity quality factor can be loosened

  20. Circuit QED with 3D cavities

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Edwar; Eder, Peter; Fischer, Michael; Goetz, Jan; Deppe, Frank; Gross, Rudolf [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, 85748 Garching (Germany); Physik-Department, TU Muenchen, 85748 Garching (Germany); Nanosystems Initiative Munich (NIM), 80799 Muenchen (Germany); Haeberlein, Max; Wulschner, Karl Friedrich [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, 85748 Garching (Germany); Physik-Department, TU Muenchen, 85748 Garching (Germany); Fedorov, Kirill; Marx, Achim [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, 85748 Garching (Germany)

    2016-07-01

    In typical circuit QED systems, on-chip superconducting qubits are coupled to integrated coplanar microwave resonators. Due to the planar geometry, the resonators are often a limiting factor regarding the total coherence of the system. Alternatively, similar hybrid systems can be realized using 3D microwave cavities. Here, we present studies on transmon qubits capacitively coupled to 3D cavities. The internal quality factors of our 3D cavities, machined out of high purity aluminum, are above 1.4 .10{sup 6} at the single photon level and a temperature of 50 mK. For characterization of the sample, we perform dispersive shift measurements up to the third energy level of the qubit. We show simulations and data describing the effect of the transmon geometry on it's capacitive properties. In addition, we present progress towards an integrated quantum memory application.

  1. MR imaging of oropharynx and oral cavity

    International Nuclear Information System (INIS)

    Vogl, T.; Markl, A.F.; Bruning, R.; Greves, G.; Kang, K.; Lissner, J.A.

    1988-01-01

    The effect of intravenously administered Gd-DTPA on signal intensity, in the oropharynx and oral cavity was analyzed, in comparison with plain imaging the examinations were carried out on 150 patients, with a 1.5-T magnetic resonance (MR) imaging unit. During and after the application of Gd-DTPA, flash images with a repetition time of 30, an echo time of 12 msec, and a 20 0 flip angle were acquired over a period of 7 minutes. In 89 patients, malignant tumors were discovered, located primarily in the oropharynx and oral cavity. Plain MR imaging was equal to or better than computed tomograph in all patients except five. Marked contrast enhancement was observed in carcinomas, sarcomas, and inflammation. The enhancement of signal intensity versus time allowed a better differentiation of histologic features. MR imaging contributes substantially to the imaging of the oropharynx and oral cavity by improved soft-tissue contrast and the capacity for multiplanar imaging

  2. Superconducting Cavity Development for the CEBAF Upgrade

    International Nuclear Information System (INIS)

    I.E. Campisi; J.R. Delayen; L.R. Doolittle; P.Kneisel; J. Mammosser; L. Phillips

    1999-01-01

    Long-term plans for CEBAF at Jefferson Lab call for achieving 12 GeV in the middle of the next decade and 24 GeV after 2010. In support of these plans, an Upgrade Cryomodule, capable of providing more than twice the operating voltage of the existing CEBAF modules within the same length, is being developed. In particular, this requires the development of superconducting cavities capable of consistently operating at gradients above 12 MV/m and Q approximately 10 10 . We have engaged in a complete review of all the processes and procedures involved in the fabrication and assembly of cavities, and are modifying our chemical processing, cleaning, and assembly facilities. While we have retained the cell shape of existing CEBAF cavities, the new superconducting structure will be substantially different in several respects, such as the higher-order-modes damping and the fundamental power coupling systems. Design features and experimental results will be presented

  3. PEP-II RF cavity revisited

    International Nuclear Information System (INIS)

    Rimmer, R.A.; Koehler, G.; Li, D.; Hartman, N.; Folwell, N.; Hodgson, J.; Ko, K.; McCandless, B.

    1999-01-01

    This report describes the results of numerical simulations of the PEP-II RF cavity performed after the completion of the construction phase of the project and comparisons are made to previous calculations and measured results. These analyses were performed to evaluate new calculation techniques for the HOM distribution and RF surface heating that were not available at the time of the original design. These include the use of a high frequency electromagnetic element in ANSYS and the new Omega 3P code to study wall losses, and the development of broadband time domain simulation methods in MAFIA for the HOM loading. The computed HOM spectrum is compared with cavity measurements and observed beam-induced signals. The cavity fabrication method is reviewed, with the benefit of hindsight, and simplifications are discussed

  4. Cavity Pressure Behaviour in Micro Injection Moulding

    DEFF Research Database (Denmark)

    Griffiths, C.A.; Dimov, S.S.; Scholz, S.

    2010-01-01

    as well as with the filling of the cavity by the polymer melt. In this paper, two parameters derived from cavity pressure over time (i.e. pressure work). The influence of four µIM parameters (melt temperature, mould temperature, injection speed, aand packing pressure) on the two pressure-related outputs...... has been investigated by moulding a micro fluidic component on three different polymers (PP, ABS, PC) using the design of experiment approach. Similar trends such as the effects of a higher injection speed in decreasing the pressure work and of a lower temperature in decreasing pressure rate have been......Process monitoring of micro injection moulding (µIM) is of crusial importance to analyse the effect of different parameter settings on the process and to assess its quality. Quality factors related to cavity pressure can provide useful information directly connected with the dyanmics of the process...

  5. Minimum wakefield achievable by waveguide damped cavity

    International Nuclear Information System (INIS)

    Lin, X.E.; Kroll, N.M.

    1995-01-01

    The authors use an equivalent circuit to model a waveguide damped cavity. Both exponentially damped and persistent (decay t -3/2 ) components of the wakefield are derived from this model. The result shows that for a cavity with resonant frequency a fixed interval above waveguide cutoff, the persistent wakefield amplitude is inversely proportional to the external Q value of the damped mode. The competition of the two terms results in an optimal Q value, which gives a minimum wakefield as a function of the distance behind the source particle. The minimum wakefield increases when the resonant frequency approaches the waveguide cutoff. The results agree very well with computer simulation on a real cavity-waveguide system

  6. Atoms and cavities: Explorations of quantum entanglement

    International Nuclear Information System (INIS)

    Raimond, J. M.; Hagley, E.; Maitre, X.; Nogues, G.; Wunderlich, C.; Brune, M.; Haroche, S.

    1999-01-01

    The interaction of circular Rydberg atoms with a high-quality microwave cavity makes it possible to realize complex quantum state manipulations. The state of an atom can be 'copied' onto the cavity. Reversing this operation at a later time with a second atom, we realize an elementary 'quantum memory' holding an atomic quantum coherence for a while in a cavity mode. We have also generated two-atom entangled states of the Einstein-Podolsky-Rosen type. At variance with previous experiments, this one implies massive particles in a completely controlled process. These entanglement manipulations can be generalized to more complex or to mesoscopic systems and open the way to new tests of fundamental aspects of the quantum world

  7. Cavity lining after excavating caries lesions

    DEFF Research Database (Denmark)

    Schwendicke, Falk; Göstemeyer, Gerd; Gluud, Christian

    2015-01-01

    OBJECTIVES: After removal of dentin caries lesions, cavity lining has been advocated. Non-clinical data support this approach, but clinical data are sparse and ambiguous. We aimed at evaluating the benefits and harms of cavity lining using meta-analysis and Trial Sequential Analysis. DATA: We...... included randomized clinical trials comparing restorations without versus with cavity lining for treating primary caries lesions. Only trials reporting failure (defined as need to re-retreat) after ≥1 year follow-up were included. Trial selection, data extraction, and risk of bias assessment were conducted....... STUDY SELECTION: From 128 studies, three randomized trials (89/130 patients or teeth), all treating primary teeth, were included. The trials had high risk of bias. All trials compared no lining versus calcium hydroxide lining after selective caries removal followed by adhesive restoration. Follow...

  8. Other relevant biological papers

    International Nuclear Information System (INIS)

    Shimizu, M.

    1989-01-01

    A considerable number of CRESP-relevant papers concerning deep-sea biology and radioecology have been published. It is the purpose of this study to call attention to them. They fall into three general categories. The first is papers of general interest. They are mentioned only briefly, and include text references to the global bibliography at the end of the volume. The second are papers that are not only mentioned and referenced, but for various reasons are described in abstract form. The last is a list of papers compiled by H.S.J. Roe specifically for this volume. They are listed in bibliographic form, and are also included in the global bibliography at the end of the volume

  9. Prominence mass supply and the cavity

    Energy Technology Data Exchange (ETDEWEB)

    Schmit, Donald J.; Innes, D. [Max Planck Institute for Solar System Research, D-37191 Katlenburg-Lindau (Germany); Gibson, S. [High Altitude Observatory, National Center for Atmospheric Research, Boulder, CO 80307 (United States); Luna, M. [Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife (Spain); Karpen, J. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2013-12-20

    A prevalent but untested paradigm is often used to describe the prominence-cavity system: the cavity is under-dense because it is evacuated by supplying mass to the condensed prominence. The thermal non-equilibrium (TNE) model of prominence formation offers a theoretical framework to predict the thermodynamic evolution of the prominence and the surrounding corona. We examine the evidence for a prominence-cavity connection by comparing the TNE model with diagnostics of dynamic extreme ultraviolet (EUV) emission surrounding the prominence, specifically prominence horns. Horns are correlated extensions of prominence plasma and coronal plasma which appear to connect the prominence and cavity. The TNE model predicts that large-scale brightenings will occur in the Solar Dynamics Observatory Atmospheric Imaging Assembly 171 Å bandpass near the prominence that are associated with the cooling phase of condensation formation. In our simulations, variations in the magnitude of footpoint heating lead to variations in the duration, spatial scale, and temporal offset between emission enhancements in the other EUV bandpasses. While these predictions match well a subset of the horn observations, the range of variations in the observed structures is not captured by the model. We discuss the implications of our one-dimensional loop simulations for the three-dimensional time-averaged equilibrium in the prominence and the cavity. Evidence suggests that horns are likely caused by condensing prominence plasma, but the larger question of whether this process produces a density-depleted cavity requires a more tightly constrained model of heating and better knowledge of the associated magnetic structure.

  10. Prominence Mass Supply and the Cavity

    Science.gov (United States)

    Schmit, Donald J.; Gibson, S.; Luna, M.; Karpen, J.; Innes, D.

    2013-01-01

    A prevalent but untested paradigm is often used to describe the prominence-cavity system; the cavity is under-dense because it it evacuated by supplying mass to the condensed prominence. The thermal non-equilibrium (TNE) model of prominence formation offers a theoretical framework to predict the thermodynamic evolutin of the prominence and the surrounding corona. We examine the evidence for a prominence-cavity connection by comparing the TNE model and diagnostics of dynamic extreme ultraviolet (EUV) emission surrounding the prominence, specifically prominence horns. Horns are correlated extensions of prminence plasma and coronal plasma which appear to connect the prominence and cavity. The TNE model predicts that large-scale brightenings will occur in the Solar Dynamics Observatory Atmospheric Imaging Assembly 171 A badpass near he prominence that are associated with the cooling phase of condensation formation. In our simulations, variations in the magnitude of footpoint heating lead to variations in the duration, spatial scale, and temporal offset between emission enhancements in the other EUV bandpasses. While these predictions match well a subset of the horn observations, the range of variations in the observed structures is not captured by the model. We discuss the implications of one-dimensional loop simulations for the three-dimensional time-averaged equilibrium in the prominence and the cavity. Evidence suggests that horns are likely caused by condensing prominence plasma, but the larger question of whether this process produces a density-depleted cavity requires a more tightly constrained model of heating and better knowledge of the associated magnetic structure.

  11. Electroacoustic oscillations in the LEP SC. cavities

    CERN Document Server

    Boussard, Daniel; Tückmantel, Joachim

    1996-01-01

    The LEP superconducting cavities have been plagued by electroacoustic oscillations. Tests have been done to eliminate these by a special feed-back loop in the tuning circuit as well as a feed-forward path, but they could only be eliminated safely up to the design field by running the cavities close to tune neglecting beam-loading compensation. This technique proved successful during the first LEP2 test run at 70 GeV. The mechanism and essential parameters driving these oscillations have been analysed as well as the corresponding stronger loading of the power coupler.

  12. Strategies for waveguide coupling for SRF cavities

    International Nuclear Information System (INIS)

    Doolittle, L.R.

    1998-01-01

    Despite widespread use of coaxial couplers in SRF cavities, a single, simple waveguide coupling can be used both to transmit generator power to a cavity, and to remove a large class of Higher Order Modes (HOMs, produced by the beam). There are balances and tradeoffs to be made, such as the coupling strength of the various frequencies, the transverse component of the coupler fields on the beam axis, and the magnitude of the surface fields and currents. This paper describes those design constraints, categories of solutions, and examples from the CEBAF Energy Upgrade studies

  13. Contamination issues in superconducting cavity technology

    International Nuclear Information System (INIS)

    Kneisel, Peter

    1997-01-01

    The application of radio-frequency superconductivity technology in particle accelerator projects has become increasingly evident in recent years. Several large scale projects around the world are either completed or close to completion, such as CEBAF, HERA, TRISTAN and LEP. And superconducting cavity technology is seriously being considered for future applications in linear colliders (TESLA), high current proton accelerators (APT, spallation neutron sources), muon colliders and free electron lasers for industrial application. The reason for this multitude of activities are matured technology based on a better understanding of the phenomena encountered in superconducting cavities and the influence of improved material properties and contamination and quality control measures

  14. Plasma processing of superconducting radio frequency cavities

    Science.gov (United States)

    Upadhyay, Janardan

    The development of plasma processing technology of superconducting radio frequency (SRF) cavities not only provides a chemical free and less expensive processing method, but also opens up the possibility for controlled modification of the inner surfaces of the cavity for better superconducting properties. The research was focused on the transition of plasma etching from two dimensional flat surfaces to inner surfaces of three dimensional (3D) structures. The results could be applicable to a variety of inner surfaces of 3D structures other than SRF cavities. Understanding the Ar/Cl2 plasma etching mechanism is crucial for achieving the desired modification of Nb SRF cavities. In the process of developing plasma etching technology, an apparatus was built and a method was developed to plasma etch a single cell Pill Box cavity. The plasma characterization was done with the help of optical emission spectroscopy. The Nb etch rate at various points of this cavity was measured before processing the SRF cavity. Cylindrical ring-type samples of Nb placed on the inner surface of the outer wall were used to measure the dependence of the process parameters on plasma etching. The measured etch rate dependence on the pressure, rf power, dc bias, temperature, Cl2 concentration and diameter of the inner electrode was determined. The etch rate mechanism was studied by varying the temperature of the outer wall, the dc bias on the inner electrode and gas conditions. In a coaxial plasma reactor, uniform plasma etching along the cylindrical structure is a challenging task due to depletion of the active radicals along the gas flow direction. The dependence of etch rate uniformity along the cylindrical axis was determined as a function of process parameters. The formation of dc self-biases due to surface area asymmetry in this type of plasma and its variation on the pressure, rf power and gas composition was measured. Enhancing the surface area of the inner electrode to reduce the

  15. Accelerating RF cavity of the Booster

    CERN Multimedia

    CERN PhotoLab

    1981-01-01

    Each of the 4 PS Booster rings has a single accelerating cavity. It consists of 2 quarter-wave ferrite-loaded resonators. There are 2 figure-of-eight loops on the ferrite loads for tuning the frequency throughout the acceleration cycle, from 3 to 8 MHz (from 50 MeV at injection to the original Booster energy of 800 MeV, 2 GeV today). The cavities have a flat design, to fit the ring-to-ring distance of 36 cm. The tube for forced-air cooling is visible in the left front. See also 8301084.

  16. Accelerating RF cavity of the Booster

    CERN Multimedia

    CERN PhotoLab

    1983-01-01

    Each of the 4 PS Booster rings has a single accelerating cavity.It consists of 2 quarter-wave ferrite-loaded resonators. 2 figure-of-eight loops tune the frequency throughout the accelerating cycle, from 3 to 8 MHz (from 50 MeV at injection to the original Booster energy of 800 MeV, 2 GeV today). The cavities have a flat design, to fit the ring-to-ring distance of 36 cm, and are forced-air cooled. The 2 round objects in the front-compartments are the final-stage power-tetrodes. See also 8111095.

  17. Instrumentation for localized superconducting cavity diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Conway, Z. A. [Argonne National Lab. (ANL), Argonne, IL (United States). Physics Division; Ge, M. [Cornell Lab. for Accelerator-Based Sciences and Education, Ithaca, NY (United States); Iwashita, Y. [Kyoto Univ. (Japan)

    2017-01-12

    Superconducting accelerator cavities are now routinely operated at levels approaching the theoretical limit of niobium. To achieve these operating levels more information than is available from the RF excitation signal is required to characterize and determine fixes for the sources of performance limitations. This information is obtained using diagnostic techniques which complement the analysis of the RF signal. In this paper we describe the operation and select results from three of these diagnostic techniques: the use of large scale thermometer arrays, second sound wave defect location and high precision cavity imaging with the Kyoto camera.

  18. Cryogenic system for TRISTAN superconducting RF cavity

    International Nuclear Information System (INIS)

    Hosoyama, K.; Hara, K.; Kabe, A.; Kojima, Yuuji; Ogitsu, T.; Sakamoto, Y.; Kawamura, S.; Ishimaru, Y.

    1990-01-01

    A cryogenic system consisting of a helium refrigerator (4 kW at 4.4 K) and a liquid helium distribution transfer system for TRISTAN 508 MHz 32 x 5-cell superconducting RF cavities was designed and constructed. After the performance test of the cryogenic system, 16 x 5-cell superconducting RF cavities in 8 cryostats were installed in underground TRISTAN electron-positron collider and connected to the helium refrigerator on the ground level through the transfer line (total length about 330 m) and cooled by liquid helium pool boiling in parallel. The cryogenic system and its operation experience are described. (author)

  19. Seismic wave interaction with underground cavities

    Science.gov (United States)

    Schneider, Felix M.; Esterhazy, Sofi; Perugia, Ilaria; Bokelmann, Götz

    2016-04-01

    Realization of the future Comprehensive Nuclear Test Ban Treaty (CTBT) will require ensuring its compliance, making the CTBT a prime example of forensic seismology. Following indications of a nuclear explosion obtained on the basis of the (IMS) monitoring network further evidence needs to be sought at the location of the suspicious event. For such an On-Site Inspection (OSI) at a possible nuclear test site the treaty lists several techniques that can be carried out by the inspection team, including aftershock monitoring and the conduction of active seismic surveys. While those techniques are already well established, a third group of methods labeled as "resonance seismometry" is less well defined and needs further elaboration. A prime structural target that is expected to be present as a remnant of an underground nuclear explosion is a cavity at the location and depth the bomb was fired. Originally "resonance seismometry" referred to resonant seismic emission of the cavity within the medium that could be stimulated by an incident seismic wave of the right frequency and observed as peaks in the spectrum of seismic stations in the vicinity of the cavity. However, it is not yet clear which are the conditions for which resonant emissions of the cavity could be observed. In order to define distance-, frequency- and amplitude ranges at which resonant emissions could be observed we study the interaction of seismic waves with underground cavities. As a generic model for possible resonances we use a spherical acoustic cavity in an elastic full-space. To solve the forward problem for the full elastic wave field around acoustic spherical inclusions, we implemented an analytical solution (Korneev, 1993). This yields the possibility of generating scattering cross-sections, amplitude spectrums and synthetic seismograms for plane incident waves. Here, we focus on the questions whether or not we can expect resonant responses in the wave field scattered from the cavity. We show

  20. Progress in diagnostic techniques for sc cavities

    International Nuclear Information System (INIS)

    Reece, C.E.

    1988-01-01

    While routinely achieved performance characteristics of superconducting cavities have now reached a level which makes them useful in large scale applications, achieving this level has come only through the knowledge gained by systematic studies of performance limiting phenomena. Despite the very real progress that has been made, the routine performance of superconducting cavities still falls far short of both the theoretical expectations and the performance of a few exception examples. It is the task of systematically applied diagnostic techniques to reveal additional information concerning the response of superconducting surfaces to applied RF fields. Here recent developments in diagnostic techniques are discussed. 18 references, 12 figures

  1. Superconducting Accelerating Cavity Pressure Sensitivity Analysis

    International Nuclear Information System (INIS)

    Rodnizki, J.; Horvits, Z.; Ben Aliz, Y.; Grin, A.; Weissman, L.

    2014-01-01

    The measured sensitivity of the cavity was evaluated and it is full consistent with the measured values. It was explored that the tuning system (the fog structure) has a significant contribution to the cavity sensitivity. By using ribs or by modifying the rigidity of the fog we may reduce the HWR sensitivity. During cool down and warming up we have to analyze the stresses on the HWR to avoid plastic deformation to the HWR since the Niobium yield is an order of magnitude lower in room temperature

  2. Short-cavity squeezing in barium

    Science.gov (United States)

    Hope, D. M.; Bachor, H-A.; Manson, P. J.; Mcclelland, D. E.

    1992-01-01

    Broadband phase sensitive noise and squeezing were experimentally observed in a system of barium atoms interacting with a single mode of a short optical cavity. Squeezing of 13 +/- 3 percent was observed. A maximum possible squeezing of 45 +/- 8 percent could be inferred for out experimental conditions, after correction for measured loss factors. Noise reductions below the quantum limit were found over a range of detection frequencies 60-170 MHz and were best for high cavity transmission and large optical depths. The amount of squeezing observed is consistent with theoretical predictions from a full quantum statistical model of the system.

  3. 1.3 GHz superconducting RF cavity program at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Ginsburg, C.M.; Arkan, T.; Barbanotti, S.; Carter, H.; Champion, M.; Cooley, L.; Cooper, C.; Foley, M.; Ge, M.; Grimm, C.; Harms, E.; /Fermilab

    2011-03-01

    At Fermilab, 9-cell 1.3 GHz superconducting RF (SRF) cavities are prepared, qualified, and assembled into cryomodules (CMs) for Project X, an International Linear Collider (ILC), or other future projects. The 1.3 GHz SRF cavity program includes targeted R&D on 1-cell 1.3 GHz cavities for cavity performance improvement. Production cavity qualification includes cavity inspection, surface processing, clean assembly, and one or more cryogenic low-power CW qualification tests which typically include performance diagnostics. Qualified cavities are welded into helium vessels and are cryogenically tested with pulsed high-power. Well performing cavities are assembled into cryomodules for pulsed high-power testing in a cryomodule test facility, and possible installation into a beamline. The overall goals of the 1.3 GHz SRF cavity program, supporting facilities, and accomplishments are described.

  4. Harnessing the mode mixing in optical fiber-tip cavities

    International Nuclear Information System (INIS)

    Podoliak, Nina; Horak, Peter; Takahashi, Hiroki; Keller, Matthias

    2017-01-01

    We present a systematic numerical study of Fabry–Pérot optical cavities with Gaussian-shape mirrors formed between tips of optical fibers. Such cavities can be fabricated by laser machining of fiber tips and are promising systems for achieving strong coupling between atomic particles and an optical field as required for quantum information applications. Using a mode mixing matrix method, we analyze the cavity optical eigenmodes and corresponding losses depending on a range of cavity-shape parameters, such as mirror radius of curvature, indentation depth and cavity length. The Gaussian shape of the mirrors causes mixing of optical modes in the cavity. We investigate the effect of the mode mixing on the coherent atom-cavity coupling as well as the mode matching between the cavity and a single-mode optical fiber. While the mode mixing is associated with increased cavity losses, it can also lead to an enhancement of the local optical field. We demonstrate that around the resonance between the fundamental and 2nd order Laguerre–Gaussian modes of the cavity it is possible to obtain 50% enhancement of the atom-cavity coupling at the cavity center while still maintaining low cavity losses and high cavity-fiber optical coupling. (paper)

  5. Influence from cavity decay on geometric quantum computation in the large-detuning cavity QED model

    International Nuclear Information System (INIS)

    Chen Changyong; Zhang Xiaolong; Deng Zhijiao; Gao Kelin; Feng Mang

    2006-01-01

    We introduce a general displacement operator to investigate the unconventional geometric quantum computation with dissipation under the model of many identical three-level atoms in a cavity, driven by a classical field. Our concrete calculation is made for the case of two atoms, based on a previous scheme [S.-B. Zheng, Phys. Rev. A 70, 052320 (2004)] for the large-detuning interaction of the atoms with the cavity mode. The analytical results we present will be helpful for experimental realization of geometric quantum computation in real cavities

  6. Analysis of mechanical fabrication experience with CEBAF's production SRF cavities

    International Nuclear Information System (INIS)

    Mammosser, J.; Kneisel, P.; Benesch, J.

    1993-06-01

    CEBAF has received a total of 360 five-cell niobium cavities, the largest group of industrially fabricated superconducting cavities so far. An extensive data base exists on the fabrication, surface treatment, assembly and cavity performance parameters. Analysis of the mechanical features of the cavities includes the following: the spread in fabrication tolerances of the cells derived from field profiles of the ''as fabricated'' cavities and the ''as fabricated'' external Q-values of the fundamental power coupler compared to dimensional deviations. A comparison is made of the pressure sensitivity of cavities made of materials from different manufacturers between 760 torr (4.2 K) and 23 torr (2 K)

  7. BIOREACTOR WITH LID FOR EASY ACCESS TO INCUBATION CAVITY

    DEFF Research Database (Denmark)

    2012-01-01

    There is provided a bioreactor which is provided with a lid (13) that facilitates access to the incubation cavity. Specifically the end wall of the incubation cavity is constituted by the lid (13) so that removal of the cap renders the incubation cavity fully accessible.......There is provided a bioreactor which is provided with a lid (13) that facilitates access to the incubation cavity. Specifically the end wall of the incubation cavity is constituted by the lid (13) so that removal of the cap renders the incubation cavity fully accessible....

  8. RF control studies for moderate beamtime coupling between SRF cavities

    International Nuclear Information System (INIS)

    Doolittle, L.R.; Wang, D.X.

    1998-01-01

    When an SRF accelerator is designed, there is motivation to move the cavities close together on the beamline. Assuming the beamline apertures are not shrunk as well, this compaction (which will increase the overall accelerating gradient and/or lower the dynamic cryogenic heat load) increases the inter-cavity coupling. Within certain limits, the control system can compensate for this coupling by retuning each of the cavities. This paper describes constraints on the RF system, tuners, couplers, and control systems that are required to provide stable operation of cavities in the presence of inter-cavity coupling that exceeds the loaded bandwidth of an individual cavity

  9. User perspectives on relevance criteria

    DEFF Research Database (Denmark)

    Maglaughlin, Kelly L.; Sonnenwald, Diane H.

    2002-01-01

    , partially relevant, or not relevant to their information need; and explained their decisions in an interview. Analysis revealed 29 criteria, discussed positively and negatively, that were used by the participants when selecting passages that contributed or detracted from a document's relevance......This study investigates the use of criteria to assess relevant, partially relevant, and not-relevant documents. Study participants identified passages within 20 document representations that they used to make relevance judgments; judged each document representation as a whole to be relevant...... matter, thought catalyst), full text (e.g., audience, novelty, type, possible content, utility), journal/publisher (e.g., novelty, main focus, perceived quality), and personal (e.g., competition, time requirements). Results further indicate that multiple criteria are used when making relevant, partially...

  10. Observing mode propagation inside a laser cavity

    CSIR Research Space (South Africa)

    Naidoo, Darryl

    2012-05-01

    Full Text Available components, to study the forward and backward propagating waves everywhere inside a laser cavity. We verify the previous theoretical-only prediction that the two fields may differ substantially in their amplitude profile, even for stable resonator systems, a...

  11. Lasers with intra-cavity phase elements

    Science.gov (United States)

    Gulses, A. Alkan; Kurtz, Russell; Islas, Gabriel; Anisimov, Igor

    2018-02-01

    Conventional laser resonators yield multimodal output, especially at high powers and short cavity lengths. Since highorder modes exhibit large divergence, it is desirable to suppress them to improve laser quality. Traditionally, such modal discriminations can be achieved by simple apertures that provide absorptive loss for large diameter modes, while allowing the lower orders, such as the fundamental Gaussian, to pass through. However, modal discrimination may not be sufficient for short-cavity lasers, resulting in multimodal operation as well as power loss and overheating in the absorptive part of the aperture. In research to improve laser mode control with minimal energy loss, systematic experiments have been executed using phase-only elements. These were composed of an intra-cavity step function and a diffractive out-coupler made of a computer-generated hologram. The platform was a 15-cm long solid-state laser that employs a neodymium-doped yttrium orthovanadate crystal rod, producing 1064 nm multimodal laser output. The intra-cavity phase elements (PEs) were shown to be highly effective in obtaining beams with reduced M-squared values and increased output powers, yielding improved values of radiance. The utilization of more sophisticated diffractive elements is promising for more difficult laser systems.

  12. Atmospheric signals produced by cavity rebound

    International Nuclear Information System (INIS)

    Jones, E.M.; App, F.N.; Whitaker, R.W.

    1993-01-01

    An analysis of the atmospheric acoustic signals produced by a class of low-yield tests conducted just below the base of the alluvial cover in Yucca Flat of the Nevada Test Site (NTS), has revealed a clear manifestation of an elastic, cavity rebound signal. We use modeling as the basis for understanding the observed phenomena

  13. Wall compliance and violin cavity modes.

    Science.gov (United States)

    Bissinger, George

    2003-03-01

    Violin corpus wall compliance, which has a substantial effect on cavity mode frequencies, was added to Shaw's two-degree-of-freedom (2DOF) network model for A0 ("main air") and A1 (lowest length mode included in "main wood") cavity modes. The 2DOF model predicts a V(-0.25) volume dependence for A0 for rigid violin-shaped cavities, to which a semiempirical compliance correction term, V(-x(c)) (optimization parameter x(c)) consistent with cavity acoustical compliance and violin-based scaling was added. Optimizing x(c) over A0 and A1 frequencies measured for a Hutchins-Schelleng violin octet yielded x(c) approximately 0.08. This markedly improved A0 and A1 frequency predictions to within approximately +/- 10% of experiment over a range of about 4.5:1 in length, 10:1 in f-hole area, 3:1 in top plate thickness, and 128:1 in volume. Compliance is a plausible explanation for A1 falling close to the "main wood" resonance, not increasingly higher for the larger instruments, which were scaled successively shorter compared to the violin for ergonomic and practical reasons. Similarly incorporating compliance for A2 and A4 (lowest lower-/upper-bout modes, respectively) improves frequency predictions within +/-20% over the octet.

  14. Bifurcation structure of an optical ring cavity

    DEFF Research Database (Denmark)

    Kubstrup, C.; Mosekilde, Erik

    1996-01-01

    One- and two-dimensional continuation techniques are applied to determine the basic bifurcation structure for an optical ring cavity with a nonlinear absorbing element (the Ikeda Map). By virtue of the periodic structure of the map, families of similar solutions develop in parameter space. Within...

  15. All-optical tunable photonic crystal cavity

    DEFF Research Database (Denmark)

    Pu, Minhao; Liu, Liu; Ou, Haiyan

    2010-01-01

    We demonstrate an ultra-small photonic crystal cavity with two resonant modes. An all-optical tuning operation based on the free-carrier plasma effect is, for the first time, realized utilizing a continuous wave light source. The termo-optical effect is minimized by isoproponal infiltration...

  16. Cavity sideband cooling of trapped molecules

    NARCIS (Netherlands)

    Kowalewski, Markus; Morigi, Giovanna; Pinkse, Pepijn Willemszoon Harry; de Vivie-Riedle, Regina

    2011-01-01

    The efficiency of cavity sideband cooling of trapped molecules is theoretically investigated for the case in which the infrared transition between two rovibrational states is used as a cycling transition. The molecules are assumed to be trapped either by a radiofrequency or optical trapping

  17. Direct Numerical Simulation of Driven Cavity Flows

    NARCIS (Netherlands)

    Verstappen, R.; Wissink, J.G.; Veldman, A.E.P.

    Direct numerical simulations of 2D driven cavity flows have been performed. The simulations exhibit that the flow converges to a periodically oscillating state at Re=11,000, and reveal that the dynamics is chaotic at Re=22,000. The dimension of the attractor and the Kolmogorov entropy have been

  18. Cavity syncronisation of underdamped Josephson junction arrays

    DEFF Research Database (Denmark)

    Barbara, P.; Filatrella, G.; Lobb, C.

    2003-01-01

    the junctions in the array and an electromagnetic cavity. Here we show that a model of a one-dimensional array of Josephson junctions coupled to a resonator can produce many features of the coherent be havior above threshold, including coherent radiation of power and the shape of the array current...

  19. Dental Sealants Prevent Cavities PSA (:60)

    Centers for Disease Control (CDC) Podcasts

    This 60 second public service announcement is based on the October 2016 CDC Vital Signs report. Dental sealants, applied soon after a child's permanent molars come in, can protect against cavities for up to nine years. Applying sealants in schools for low-income children could save millions in dental treatment costs.

  20. The Heimlich Valve for Pleural Cavity Drainage

    African Journals Online (AJOL)

    The ANNALS of AFRICAN SURGERY | www.annalsofafricansurgery.com. The ANNALS of AFRICAN SURGERY. July 2016 Volume 13 Issue 2 45. The Heimlich Valve for Pleural Cavity Drainage. Winston Ominde Makanga1, Andrew Nyaoncha Nyangau2 , Benjamin Njoga Njihia3. 1. St Mary's Mission Hospital, Elementaita.

  1. Cavity optomechanics -- beyond the ground state

    Science.gov (United States)

    Meystre, Pierre

    2011-05-01

    The coupling of coherent optical systems to micromechanical devices, combined with breakthroughs in nanofabrication and in ultracold science, has opened up the exciting new field of cavity optomechanics. Cooling of the vibrational motion of a broad range on oscillating cantilevers and mirrors near their ground state has been demonstrated, and the ground state of at least one such system has now been reached. Cavity optomechanics offers much promise in addressing fundamental physics questions and in applications such as the detection of feeble forces and fields, or the coherent control of AMO systems and of nanoscale electromechanical devices. However, these applications require taking cavity optomechanics ``beyond the ground state.'' This includes the generation and detection of squeezed and other non-classical states, the transfer of squeezing between electromagnetic fields and motional quadratures, and the development of measurement schemes for the characterization of nanomechanical structures. The talk will present recent ``beyond ground state'' developments in cavity optomechanics. We will show how the magnetic coupling between a mechanical membrane and a BEC - or between a mechanical tuning fork and a nanoscale cantilever - permits to control and monitor the center-of-mass position of the mechanical system, and will comment on the measurement back-action on the membrane motion. We will also discuss of state transfer between optical and microwave fields and micromechanical devices. Work done in collaboration with Dan Goldbaum, Greg Phelps, Keith Schwab, Swati Singh, Steve Steinke, Mehmet Tesgin, and Mukund Vengallatore and supported by ARO, DARPA, NSF, and ONR.

  2. Congenital malformation of inner ear, single cavity

    International Nuclear Information System (INIS)

    Torres Pazmino, Julio Cesar; Marrugo Pardo, Gilberto Eduardo

    2010-01-01

    Congenital malformations of the inner ear are rare conditions, but their detection requires high diagnostic accuracy. In this report we describe the case of a patient with single or common cavity, discuss the corresponding radiological images, describe the treatment of this patient with a cochlear implant, and review the classification and differential diagnosis of the other anomalies of the inner ear.

  3. Deep-ultraviolet cavity ringdown spectroscopy

    NARCIS (Netherlands)

    Sneep, M.C.; Hannemann, S.; van Duijn, E.J.; Ubachs, W.M.G.

    2004-01-01

    The sensitive optical detection technique of cavity ringdown spectroscopy is extended to the wavelength range 197-204 nm. A novel design narrowband Fourier-transform-limited laser is used, and the technique is applied to gas-phase extinction measurements in CO

  4. Strain absorbent modules for cavity filling

    Energy Technology Data Exchange (ETDEWEB)

    1981-04-01

    Strain absorbent modules made from weldmesh panels and helical steel binders can be used, together with timber packing, to support the roof and sides of cavities instead of softwood and hardwood nogs. A description of these modules and a series of load tests and underground trials carried out on the modules is given.

  5. Pressurized rf cavities in ionizing beams

    Directory of Open Access Journals (Sweden)

    B. Freemire

    2016-06-01

    Full Text Available A muon collider or Higgs factory requires significant reduction of the six dimensional emittance of the beam prior to acceleration. One method to accomplish this involves building a cooling channel using high pressure gas filled radio frequency cavities. The performance of such a cavity when subjected to an intense particle beam must be investigated before this technology can be validated. To this end, a high pressure gas filled radio frequency (rf test cell was built and placed in a 400 MeV beam line from the Fermilab linac to study the plasma evolution and its effect on the cavity. Hydrogen, deuterium, helium and nitrogen gases were studied. Additionally, sulfur hexafluoride and dry air were used as dopants to aid in the removal of plasma electrons. Measurements were made using a variety of beam intensities, gas pressures, dopant concentrations, and cavity rf electric fields, both with and without a 3 T external solenoidal magnetic field. Energy dissipation per electron-ion pair, electron-ion recombination rates, ion-ion recombination rates, and electron attachment times to SF_{6} and O_{2} were measured.

  6. AGN Heating Through Cavities and Shocks

    NARCIS (Netherlands)

    Nulsen, P.E.J.; Jones, C.; Forman, W.R.; David, L.P.; McNamara, B.R.; Rafferty, D.A.; Bîrzan, L.; Wise, M.

    2007-01-01

    Three comments are made on AGN heating of cooling flows. A simple physical argument is used to show that the enthalpy of a buoyant radio lobe is converted to heat in its wake. Thus, a significant part of ``cavity'' enthalpy is likely to end up as heat. Second, the properties of the repeated weak

  7. Magnetic shielding for superconducting RF cavities

    Science.gov (United States)

    Masuzawa, M.; Terashima, A.; Tsuchiya, K.; Ueki, R.

    2017-03-01

    Magnetic shielding is a key technology for superconducting radio frequency (RF) cavities. There are basically two approaches for shielding: (1) surround the cavity of interest with high permeability material and divert magnetic flux around it (passive shielding); and (2) create a magnetic field using coils that cancels the ambient magnetic field in the area of interest (active shielding). The choice of approach depends on the magnitude of the ambient magnetic field, residual magnetic field tolerance, shape of the magnetic shield, usage, cost, etc. However, passive shielding is more commonly used for superconducting RF cavities. The issue with passive shielding is that as the volume to be shielded increases, the size of the shielding material increases, thereby leading to cost increase. A recent trend is to place a magnetic shield in a cryogenic environment inside a cryostat, very close to the cavities, reducing the size and volume of the magnetic shield. In this case, the shielding effectiveness at cryogenic temperatures becomes important. We measured the permeabilities of various shielding materials at both room temperature and cryogenic temperature (4 K) and studied shielding degradation at that cryogenic temperature.

  8. Construction of the LITL cavity structure

    International Nuclear Information System (INIS)

    Itoh, S.; Masuda, S.; Ukai, Y.; Hirao, Y.

    1984-01-01

    This report presents briefly the mechanical consideration for the 100 MHz four-vane RFQ (radio frequency quadrupole accelerator) structure construction. At first, the theoretical vane shape required to obtain the RFQ electric field distribution was determined. A numerically controlled milling machine was employed for the precise machining of the complicated shape. The data sets for NC machining and for checking the size of three-dimensional coordinates were made up. A small vane model was machined by way of trial experiment to check the data to verify the circular interpolation programmed NC machining method, and to investigate cutter interference. The errors in the measurement in machining were less than +- 30 micrometer. The resonator tank is 56 cm in inner diameter and 138 cm in length, and is made of mild steel of 35 mm thickness. The inside wall was plated with copper thickly. Various conditions for the copper plating were investigated. Four vanes were assembled within the cavity of the RFQ. The vanes were built in the cavity tank with high dimensional accuracy. It was a matter of primary concern to design acceptable mechanical rf joints and select suitable rf contact elements for a high Q value of the RFQ resonator cavity. Finally, the Q value was measured, and was 10,600. The cavity was able to be evacuated to 10 -7 Torr. (Kato, T.)

  9. A prototype superconducting cavity for TRISTAN

    International Nuclear Information System (INIS)

    Furuya, T.; Hara, K.; Hosoyama, K.

    1987-01-01

    Following the feasibility study on the 3-cell superconducting cavity in the TRISTAN Accumulation Ring (TAR), a 5-cell 508 MHz Nb cavity was constructed and tested in the TAR. The cavity was equipped with a RF input coupler on a beam pipe, two HOM couplers on the other beam pipe and two additional HOM couplers on the equator of an end cell. The maximum accelerating field (Eaxx) was 4.5 MV/m with a Q value of about 1x10 9 at 4.2 deg K. The field was limited by the electron field emission and neither electron multipacting nor breakdown caused by couplers was observed. Damping of the HOM was sufficient and the input coupler was tested up to 82 KW in total reflection. A frequency tuning system consisted of two piezo electric and mechanical tuners. The piezo tuner was fast enough and the mechanical tuner covered wide range. In the beam test, the single bunch electron current of 29 mA was captured by the superconducting cavity alone and 13 mA was accelerated to 4.8 GeV. The maximum power transferred to the beam was 26 KW. The refrigeration system worked very stably

  10. Natural convection inside an irregular porous cavity

    International Nuclear Information System (INIS)

    Beltran, Jorge I. LLagostera; Trevisan, Osvair Vidal

    1990-01-01

    Natural convection flow induced by heating from below in a irregular porous cavity is investigated numerically. The influence of the modified Rayleigh number and geometric ratios on heat transfer and fluid flow is studied. Global and local Nusselt for Rayleigh numbers covering the range 0 - 1600 and for several geometric ratios. The fluid flow and the temperature field are illustrated by contour maps. (author)

  11. Plasma Evolution within an Erupting Coronal Cavity

    Science.gov (United States)

    Long, David M.; Harra, Louise K.; Matthews, Sarah A.; Warren, Harry P.; Lee, Kyoung-Sun; Doschek, George A.; Hara, Hirohisa; Jenkins, Jack M.

    2018-03-01

    Coronal cavities have previously been observed to be associated with long-lived quiescent filaments and are thought to correspond to the associated magnetic flux rope. Although the standard flare model predicts a coronal cavity corresponding to the erupting flux rope, these have only been observed using broadband imaging data, restricting an analysis to the plane-of-sky. We present a unique set of spectroscopic observations of an active region filament seen erupting at the solar limb in the extreme ultraviolet. The cavity erupted and expanded rapidly, with the change in rise phase contemporaneous with an increase in nonthermal electron energy flux of the associated flare. Hot and cool filamentary material was observed to rise with the erupting flux rope, disappearing suddenly as the cavity appeared. Although strongly blueshifted plasma continued to be observed flowing from the apex of the erupting flux rope, this outflow soon ceased. These results indicate that the sudden injection of energy from the flare beneath forced the rapid eruption and expansion of the flux rope, driving strong plasma flows, which resulted in the eruption of an under-dense filamentary flux rope.

  12. Lambda shifted photonic crystal cavity laser

    DEFF Research Database (Denmark)

    Schubert, Martin; Skovgård, Troels Suhr; Ek, Sara

    2010-01-01

    We propose and demonstrate an alternative type of photonic crystal laser design that shifts all the holes in the lattice by a fixed fraction of the targeted emission wavelength. The structures are realized in InGaAsP =1.15 with InGaAsP quantum wells =1.52 as gain material. Cavities with shifts of...

  13. Shear Layer Dynamics in Resonating Cavity Flows

    National Research Council Canada - National Science Library

    Ukeiley, Lawrence

    2004-01-01

    .... The PIV data was also combined with the surface pressure measurements through the application of the Quadratic Stochastic Estimation procedure to provide time resolved snapshots of the flow field. Examination of these results indicate the strong pumping action of the cavity regardless of whether resonance existed and was used to visualize the large scale structures interacting with the aft wall.

  14. Multipacting studies in elliptic SRF cavities

    Science.gov (United States)

    Prakash, Ram; Jana, Arup Ratan; Kumar, Vinit

    2017-09-01

    Multipacting is a resonant process, where the number of unwanted electrons resulting from a parasitic discharge rapidly grows to a larger value at some specific locations in a radio-frequency cavity. This results in a degradation of the cavity performance indicators (e.g. the quality factor Q and the maximum achievable accelerating gradient Eacc), and in the case of a superconducting radiofrequency (SRF) cavity, it leads to a quenching of superconductivity. Numerical simulations are essential to pre-empt the possibility of multipacting in SRF cavities, such that its design can be suitably refined to avoid this performance limiting phenomenon. Readily available computer codes (e.g.FishPact, MultiPac,CST-PICetc.) are widely used to simulate the phenomenon of multipacting in such cases. Most of the contemporary two dimensional (2D) codes such as FishPact, MultiPacetc. are unable to detect the multipacting in elliptic cavities because they use a simplistic secondary emission model, where it is assumed that all the secondary electrons are emitted with same energy. Some three-dimensional (3D) codes such as CST-PIC, which use a more realistic secondary emission model (Furman model) by following a probability distribution for the emission energy of secondary electrons, are able to correctly predict the occurrence of multipacting. These 3D codes however require large data handling and are slower than the 2D codes. In this paper, we report a detailed analysis of the multipacting phenomenon in elliptic SRF cavities and development of a 2D code to numerically simulate this phenomenon by employing the Furman model to simulate the secondary emission process. Since our code is 2D, it is faster than the 3D codes. It is however as accurate as the contemporary 3D codes since it uses the Furman model for secondary emission. We have also explored the possibility to further simplify the Furman model, which enables us to quickly estimate the growth rate of multipacting without

  15. Accoustic Localization of Breakdown in Radio Frequency Accelerating Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Lane, Peter Gwin [IIT, Chicago

    2016-07-01

    Current designs for muon accelerators require high-gradient radio frequency (RF) cavities to be placed in solenoidal magnetic fields. These fields help contain and efficiently reduce the phase space volume of source muons in order to create a usable muon beam for collider and neutrino experiments. In this context and in general, the use of RF cavities in strong magnetic fields has its challenges. It has been found that placing normal conducting RF cavities in strong magnetic fields reduces the threshold at which RF cavity breakdown occurs. To aid the effort to study RF cavity breakdown in magnetic fields, it would be helpful to have a diagnostic tool which can localize the source of breakdown sparks inside the cavity. These sparks generate thermal shocks to small regions of the inner cavity wall that can be detected and localized using microphones attached to the outer cavity surface. Details on RF cavity sound sources as well as the hardware, software, and algorithms used to localize the source of sound emitted from breakdown thermal shocks are presented. In addition, results from simulations and experiments on three RF cavities, namely the Aluminum Mock Cavity, the High-Pressure Cavity, and the Modular Cavity, are also given. These results demonstrate the validity and effectiveness of the described technique for acoustic localization of breakdown.

  16. Scalable cavity-QED-based scheme of generating entanglement of atoms and of cavity fields

    OpenAIRE

    Lee, Jaehak; Park, Jiyong; Lee, Sang Min; Lee, Hai-Woong; Khosa, Ashfaq H.

    2008-01-01

    We propose a cavity-QED-based scheme of generating entanglement between atoms. The scheme is scalable to an arbitrary number of atoms, and can be used to generate a variety of multipartite entangled states such as the Greenberger-Horne-Zeilinger, W, and cluster states. Furthermore, with a role switching of atoms with photons, the scheme can be used to generate entanglement between cavity fields. We also introduce a scheme that can generate an arbitrary multipartite field graph state.

  17. Thermal behaviour analysis of SRF cavities and superconducting HOM couplers

    International Nuclear Information System (INIS)

    Fouaidy, M.; Junquera, T.

    1993-01-01

    Two individual papers appear in this report, titled Thermal model calculations in superconducting RF cavities, and Thermal study of HOM couplers for superconducting RF cavities. Both were indexed separately for the INIS database. (R.P.)

  18. Microencapsulation of silicon cavities using a pulsed excimer laser

    KAUST Repository

    Sedky, Sherif M.; Tawfik, Hani H.; Ashour, Mohamed; Graham, Andrew B.; Provine, John W.; Wang, Qingxiao; Zhang, Xixiang; Howe, Roger T.

    2012-01-01

    This work presents a novel low thermal-budget technique for sealing micromachined cavities in silicon. Cavities are sealed without deposition, similar to the silicon surface-migration sealing process. In contrast to the 1100°C furnace anneal

  19. Childhood Oral Cavity Cancer Treatment (PDQ®)—Patient Version

    Science.gov (United States)

    Oral cavity cancer in children is usually lymphoma or sarcoma, but most tumors of the mouth are benign. Get information about the risk factors, symptoms, tests to diagnose, and treatment of oral cavity cancer in this expert-reviewed summary.

  20. Microfabrication of cavities in polydimethylsiloxane using DRIE silicon molds

    OpenAIRE

    Giang, Ut-Binh T.; Lee, Dooyoung; King, Michael R.; DeLouise, Lisa A.

    2007-01-01

    We present a novel method to create cavities in PDMS that is simple and exhibits wide process latitude allowing control over the radius of curvature to form shallow concave pits or deep spherical cavities.

  1. Effect of cavity disinfectants on antibacterial activity and microtensile bond strength in class I cavity.

    Science.gov (United States)

    Kim, Bo-Ram; Oh, Man-Hwan; Shin, Dong-Hoon

    2017-05-31

    This study was performed to compare the antibacterial activities of three cavity disinfectants [chlorhexidine (CHX), NaOCl, urushiol] and to evaluate their effect on the microtensile bond strength of Scotchbond Universal Adhesive (3M-ESPE, St. Paul, MN, USA) in class I cavities. In both experiments, class I cavities were prepared in dentin. After inoculation with Streptococcus mutans, the cavities of control group were rinsed and those of CHX, NaOCl and urushiol groups were treated with each disinfectant. Standardized amounts of dentin chips were collected and number of S. mutans was determined. Following the same cavity treatment, same adhesive was applied in etch-and-rinse mode. Then, microtensile bond strength was evaluated. The number of S. mutans was significantly reduced in the cavities treated with CHX, NaOCl, and urushiol compared with control group (p<0.05). However, there was a significant bond strength reduction in NaOCl group, which showed statistical difference compared to the other groups (p<0.05).

  2. Cavity Processing and Preparation of 650 MHz Elliptical Cell Cavities for PIP-II

    Energy Technology Data Exchange (ETDEWEB)

    Rowe, Allan [Fermilab; Chandrasekaran, Saravan Kumar [Fermilab; Grassellino, Anna [Fermilab; Melnychuk, Oleksandr [Fermilab; Merio, Margherita [Fermilab; Reid, Thomas [Argonne (main); Sergatskov, Dmitri [Fermilab

    2017-05-01

    The PIP-II project at Fermilab requires fifteen 650 MHz SRF cryomodules as part of the 800 MeV LINAC that will provide a high intensity proton beam to the Fermilab neutrino program. A total of fifty-seven high-performance SRF cavities will populate the cryomodules and will operate in both pulsed and continuous wave modes. These cavities will be processed and prepared for performance testing utilizing adapted cavity processing infrastructure already in place at Fermilab and Argonne. The processing recipes implemented for these structures will incorporate state-of-the art processing and cleaning techniques developed for 1.3 GHz SRF cavities for the ILC, XFEL, and LCLS-II projects. This paper describes the details of the processing recipes and associated chemistry, heat treatment, and cleanroom processes at the Fermilab and Argonne cavity processing facilities. This paper also presents single and multi-cell cavity test results with quality factors above 5·10¹⁰ and accelerating gradients above 30 MV/m.

  3. Scheme for quantum state manipulation in coupled cavities

    Science.gov (United States)

    Lin, Jin-Zhong

    By controlling the parameters of the system, the effective interaction between different atoms is achieved in different cavities. Based on the interaction, scheme to generate three-atom Greenberger-Horne-Zeilinger (GHZ) is proposed in coupled cavities. Spontaneous emission of excited states and decay of cavity modes can be suppressed efficiently. In addition, the scheme is robust against the variation of hopping rate between cavities.

  4. Resonant cavity enhanced multi-analyte sensing

    Science.gov (United States)

    Bergstein, David Alan

    Biological research and medicine increasingly depend on interrogating binding interactions among small segments of DNA, RNA, protein, and bio-specific small molecules. Microarray technology, which senses the affinity for target molecules in solution for a multiplicity of capturing agents fixed to a surface, has been used in biological research for gene expression profiling and in medicine for molecular biomarker detection. Label-free affinity sensing is preferable as it avoids fluorescent labeling of the target molecules, reducing test cost and variability. The Resonant Cavity Imaging Biosensor (RCIB) is a label-free optical inference based technique introduced that scales readily to high throughput and employs an optical resonant cavity to enhance sensitivity by a factor of 100 or more. Near-infrared light centered at 1512.5 nm couples resonantly through a cavity constructed from Si/SiO2 Bragg reflectors, one of which serves as the binding surface. As the wavelength is swept 5 nm, an Indium-Gallium-Arsenide digital camera monitors cavity transmittance at each pixel with resolution 128 x 128. A wavelength shift in the local resonant response of the optical cavity indicates binding. Positioning the sensing surface with respect to the standing wave pattern of the electric field within the cavity, one can control the sensitivity of the measurement to the presence of bound molecules thereby enhancing or suppressing sensitivity where appropriate. Transmitted intensity at thousands of pixel locations are recorded simultaneously in a 10 s, 5 nm scan. An initial proof-of-principle setup was constructed. A sample was fabricated with 25, 100 mum wide square regions, each with a different density of 1 mum square depressions etched 12 nm into the S1O 2 surface. The average depth of each etched region was found with 0.05 nm RMS precision when the sample remains loaded in the setup and 0.3 nm RMS precision when the sample is removed and replaced. Selective binding of the protein

  5. 21 CFR 872.3250 - Calcium hydroxide cavity liner.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Calcium hydroxide cavity liner. 872.3250 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3250 Calcium hydroxide cavity liner. (a) Identification. A calcium hydroxide cavity liner is a device material intended to be applied to the interior of a...

  6. 21 CFR 872.6030 - Oral cavity abrasive polishing agent.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Oral cavity abrasive polishing agent. 872.6030... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6030 Oral cavity abrasive polishing agent. (a) Identification. An oral cavity abrasive polishing agent is a device in paste or powder form...

  7. Inhibited emission of electromagnetic modes confined in subwavelength cavities

    International Nuclear Information System (INIS)

    Le Thomas, N.; Houdre, R.

    2011-01-01

    We experimentally demonstrate the active inhibition of subwavelength confined cavity modes emission and quality factor enhancement by controlling the cavity optical surrounding. The intrinsic radiation angular spectrum of modes confined in planar photonics crystal cavities as well as its modifications depending on the environment are inferred via a transfer matrix modeling and k-space imaging.

  8. Fundamental limitations of cavity-assisted atom interferometry

    Science.gov (United States)

    Dovale-Álvarez, M.; Brown, D. D.; Jones, A. W.; Mow-Lowry, C. M.; Miao, H.; Freise, A.

    2017-11-01

    Atom interferometers employing optical cavities to enhance the beam splitter pulses promise significant advances in science and technology, notably for future gravitational wave detectors. Long cavities, on the scale of hundreds of meters, have been proposed in experiments aiming to observe gravitational waves with frequencies below 1 Hz, where laser interferometers, such as LIGO, have poor sensitivity. Alternatively, short cavities have also been proposed for enhancing the sensitivity of more portable atom interferometers. We explore the fundamental limitations of two-mirror cavities for atomic beam splitting, and establish upper bounds on the temperature of the atomic ensemble as a function of cavity length and three design parameters: the cavity g factor, the bandwidth, and the optical suppression factor of the first and second order spatial modes. A lower bound to the cavity bandwidth is found which avoids elongation of the interaction time and maximizes power enhancement. An upper limit to cavity length is found for symmetric two-mirror cavities, restricting the practicality of long baseline detectors. For shorter cavities, an upper limit on the beam size was derived from the geometrical stability of the cavity. These findings aim to aid the design of current and future cavity-assisted atom interferometers.

  9. The Spindle Cell Neoplasms of the Oral Cavity.

    Science.gov (United States)

    Shamim, Thorakkal

    2015-01-01

    Spindle cell neoplasms are defined as neoplasms that consist of spindle-shaped cells in the histopathology. Spindle cell neoplasms can affect the oral cavity. In the oral cavity, the origin of the spindle cell neoplasms may be traced to epithelial, mesenchymal and odontogenic components. This article aims to review the spindle cell neoplasms of the oral cavity with emphasis on histopathology.

  10. Effects of prescribed burns on wintering cavity-nesting birds

    Science.gov (United States)

    Heather L. Bateman; Margaret A. O' Connell

    2006-01-01

    Primary cavity-nesting birds play a critical role in forest ecosystems by excavating cavities later used by other birds and mammals as nesting or roosting sites. Several species of cavity-nesting birds are non-migratory residents and consequently subject to winter conditions. We conducted winter bird counts from 1998 to 2000 to examine the abundance and habitat...

  11. Heat or mass transfer from an open cavity

    NARCIS (Netherlands)

    Kuiken, H.K.

    1978-01-01

    This paper presents a mathematical model for heat or mass transfer from an open cavity. It is assumed that the Péclet number, based on conditions at the cavity, and the Prandtl number are both large. The model assumes heat- or mass-transfer boundary layers at the rim of the cavity vortex flow. Heat

  12. Uniform irradiation of irregularly shaped cavities for photodynamic therapy

    NARCIS (Netherlands)

    Rem, A. I.; van Gemert, M. J.; van der Meulen, F. W.; Gijsbers, G. H.; Beek, J. F.

    1997-01-01

    It is difficult to achieve a uniform light distribution in irregularly shaped cavities. We have conducted a study on the use of hollow 'integrating' moulds for more uniform light delivery of photodynamic therapy in irregularly shaped cavities such as the oral cavity. Simple geometries such as a

  13. Perturbed Partial Cavity Drag Reduction at High Reynolds Numbers

    Science.gov (United States)

    Makiharju, Simo; Elbing, Brian; Wiggins, Andrew; Dowling, David; Perlin, Marc; Ceccio, Steven

    2010-11-01

    Ventilated partial cavities were investigated at Reynolds numbers to 80 million. These cavities could be suitable for friction drag reduction on ocean going vessels and thereby lead to environmental and economical benefits. The test model was a 3.05 m wide by 12.9 m long flat plate, with a 0.18 m backward-facing step and a cavity-terminating beach, which had an adjustable slope, tilt and height. The step and beach trapped a ventilated partial cavity over the longitudinal mid-section of the model. Large-scale flow perturbations, mimicking the effect of ambient ocean waves were investigated. For the conditions tested a cavity could be maintained under perturbed flow conditions when the gas flux supplied was greater than the minimum required to maintain a cavity under steady conditions, with larger perturbations requiring more excess gas flux to maintain the cavity. High-speed video was used to observe the unsteady three dimensional cavity closure, the overall cavity shape, and the cavity oscillations. Cavities with friction drag reduction exceeding 95% were attained at optimal conditions. A simplified energy cost-benefit analysis of partial cavity drag reduction was also performed. The results suggest that PCDR could potentially lead to energy savings.

  14. Fundamental Power Couplers for Superconducting Cavities

    International Nuclear Information System (INIS)

    Isidoro E. Campisi

    2001-01-01

    Fundamental power couplers (FPC's) for superconducting cavities must meet very strict requirements to perform at high power levels (hundreds of kilowatts) and in a variety of conditions (CS, pulsed, travelling wave, standing wave) without adversely affecting the performance of the cavities they are powering. Producing good coupler designs and achieving operational performances in accelerator environments are challenging tasks that have traditionally involved large resources from many laboratories. The designs involve state-of-the-art activities in RF, cryogenic and mechanical engineering, materials science, vacuum technology, and electromagnetic field modeling. Handling, assembly and conditioning procedures have been developed to achieve ever-increasing power levels and more reliable operation. In this paper, the technical issues associated with the design, construction, assembly, processing, and operation of FPC's will be reviewed, together with the progress in FPC activities in several laboratories during the past few years

  15. Tunable Q-Factor RF Cavity

    Energy Technology Data Exchange (ETDEWEB)

    Balcazar, Mario D. [Fermilab; Yonehara, Katsuya [Fermilab; Moretti, Alfred [Fermilab; Kazakevitch, Gregory [Fermilab

    2018-01-01

    Intense neutrino beam is a unique probe for researching beyond the standard model. Fermilab is the main institution to produce the most powerful and widespectrum neutrino beam. From that respective, a radiation robust beam diagnostic system is a critical element in order to maintain the quality of the neutrino beam. Within this context, a novel radiation-resistive beam profile monitor based on a gasfilled RF cavity is proposed. The goal of this measurement is to study a tunable Qfactor RF cavity to determine the accuracy of the RF signal as a function of the quality factor. Specifically, measurement error of the Q-factor in the RF calibration is investigated. Then, the RF system will be improved to minimize signal error.

  16. Spiral loaded cavities for heavy ion acceleration

    International Nuclear Information System (INIS)

    Schempp, A.; Klein, H.

    1976-01-01

    A transmission line theory of the spiral resonator has been performed and the calculated and measured properties will be compared. Shunt impedances up to 50 MΩ/m have been measured. In a number of high power tests the structure has been tested and its electrical and mechanical stability has been investigated. The static frequency shift due to ponderomotoric forces was between 0.2 and 50 kHz/kW dependent on the geometrical parameters of the spirals. The maximum field strength obtained on the axis was 16 MV/m in pulsed operation and 9.2 MV/m in cw, corresponding to a voltage gain per cavity of up to 0.96 MV. The results show that spiral resonators are well suited as heavy ion accelerator cavities. (author)

  17. Investigation of free air in peritoneal cavity

    International Nuclear Information System (INIS)

    Park, Sam Gyoun; Park, Bok Hwan; Lee, Dong Hoon; Oh, Jang Suk

    1972-01-01

    On the radiographic findings of simple abdomen, detection of free air in peritoneal cavity indicates a perforation of hollow viscus. In general, free air in abdomen indicate perforation of hollow viscus caused by various disease conditions, i.e. perforation of peptic ulcer, ulcerating malignancy, colon diverticulitis and rupture of pneumatosis cystoides intestinale etc., or by trauma, however it can be rarely noticeable in the cases of intraabdominal infection with overgrowth of gas forming organisms. Eighty eight cases of free air in peritoneal cavity were analysed during the period from July, 1970 to August, 1972 at Kyungpook National University Hospital. As shown in the following tables, various clinical findings were analysed; overview of cases, causating factors and location of rupture, and it's seasonal preponderance

  18. Quantum Private Comparison via Cavity QED

    International Nuclear Information System (INIS)

    Ye Tian-Yu

    2017-01-01

    The first quantum private comparison (QPC) protocol via cavity quantum electrodynamics (QED) is proposed in this paper by making full use of the evolution law of atom via cavity QED, where the third party (TP) is allowed to misbehave on his own but cannot conspire with either of the two users. The proposed protocol adopts two-atom product states rather than entangled states as the initial quantum resource, and only needs single-atom measurements for two users. Both the unitary operations and the quantum entanglement swapping operation are not necessary for the proposed protocol. The proposed protocol can compare the equality of one bit from each user in each round comparison with one two-atom product state. The proposed protocol can resist both the outside attack and the participant attack. Particularly, it can prevent TP from knowing two users’ secrets. Furthermore, the qubit efficiency of the proposed protocol is as high as 50%. (paper)

  19. Quantum networks based on cavity QED

    Energy Technology Data Exchange (ETDEWEB)

    Ritter, Stephan; Bochmann, Joerg; Figueroa, Eden; Hahn, Carolin; Kalb, Norbert; Muecke, Martin; Neuzner, Andreas; Noelleke, Christian; Reiserer, Andreas; Uphoff, Manuel; Rempe, Gerhard [Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching (Germany)

    2014-07-01

    Quantum repeaters require an efficient interface between stationary quantum memories and flying photons. Single atoms in optical cavities are ideally suited as universal quantum network nodes that are capable of sending, storing, retrieving, and even processing quantum information. We demonstrate this by presenting an elementary version of a quantum network based on two identical nodes in remote, independent laboratories. The reversible exchange of quantum information and the creation of remote entanglement are achieved by exchange of a single photon. Quantum teleportation is implemented using a time-resolved photonic Bell-state measurement. Quantum control over all degrees of freedom of the single atom also allows for the nondestructive detection of flying photons and the implementation of a quantum gate between the spin state of the atom and the polarization of a photon upon its reflection from the cavity. Our approach to quantum networking offers a clear perspective for scalability and provides the essential components for the realization of a quantum repeater.

  20. Prototype rf cavity for the HISTRAP accelerator

    International Nuclear Information System (INIS)

    Mosko, S.W.; Dowling, D.T.; Olsen, D.K.

    1989-01-01

    HISTRAP, a proposed synchrotron-cooling-storage ring designed to both accelerate and decelerate very highly charged very heavy ions for atomic physics research, requires an rf accelerating system to provide /+-/2.5 kV of peak accelerating voltage per turn while tuning through a 13.5:1 frequency range in a fraction of a second. A prototype half-wave, single gap rf cavity with biased ferrite tuning was built and tested over a continuous tuning range of 200 kHz through 2.7 MHz. Initial test results establish the feasibility of using ferrite tuning at the required rf power levels. The resonant system is located entirely outside of the accelerator's 15cm ID beam line vacuum enclosure except for a single rf window which serves as an accelerating gap. Physical separation of the cavity and the beam line permits in situ vacuum baking of the beam line at 300/degree/C

  1. Modeling of Coupled Nano-Cavity Lasers

    DEFF Research Database (Denmark)

    Skovgård, Troels Suhr

    -of-states and it is argued that Purcell enhancement should also be included in stimulated recombination term, contrary to the common practice in the literature. It is shown that for quantum well devices, the Purcell enhancement is effectively independent of the cavity quality factor due to the broad electronic density......-of-states relative to the optical density-of-states. The low effective Purcell eect for quantum well devices limits the highest possible modulation bandwidth to a few tens of gigahertz, which is comparable to the performance of conventional diode lasers. Compared to quantum well devices, quantum dot devices have...... is useful for design of coupled systems. A tight-binding description for coupled nanocavity lasers is developed and employed to investigate the phase-locking behavior for the system of two coupled cavities. Phase-locking is found to be critically dependent on exact parameter values and to be dicult...

  2. Adverse drug events in the oral cavity.

    Science.gov (United States)

    Yuan, Anna; Woo, Sook-Bin

    2015-01-01

    Adverse reactions to medications are common and may have a variety of clinical presentations in the oral cavity. Targeted therapies and the new biologic agents have revolutionized the treatment of cancers, autoimmune diseases, and inflammatory and rheumatologic diseases but have also been associated with adverse events in the oral cavity. Some examples include osteonecrosis, seen with not only bisphosphonates but also antiangiogenic agents, and the distinctive ulcers caused by mammalian target of rapamycin inhibitors. As newer therapeutic agents are approved, it is likely that more adverse drug events will be encountered. This review describes the most common clinical presentations of oral mucosal reactions to medications, namely, xerostomia, lichenoid reactions, ulcers, bullous disorders, pigmentation, fibrovascular hyperplasia, white lesions, dysesthesia, osteonecrosis, infection, angioedema, and malignancy. Oral health care providers should be familiar with such events, as they will encounter them in their practice. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Investigation of free air in peritoneal cavity

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sam Gyoun; Park, Bok Hwan; Lee, Dong Hoon; Oh, Jang Suk [Kyungpook National University School of Medicine, Taegu (Korea, Republic of)

    1972-12-15

    On the radiographic findings of simple abdomen, detection of free air in peritoneal cavity indicates a perforation of hollow viscus. In general, free air in abdomen indicate perforation of hollow viscus caused by various disease conditions, i.e. perforation of peptic ulcer, ulcerating malignancy, colon diverticulitis and rupture of pneumatosis cystoides intestinale etc., or by trauma, however it can be rarely noticeable in the cases of intraabdominal infection with overgrowth of gas forming organisms. Eighty eight cases of free air in peritoneal cavity were analysed during the period from July, 1970 to August, 1972 at Kyungpook National University Hospital. As shown in the following tables, various clinical findings were analysed; overview of cases, causating factors and location of rupture, and it's seasonal preponderance.

  4. HPV and cancer of the oral cavity.

    Science.gov (United States)

    Hübbers, Christian U; Akgül, Baki

    2015-01-01

    Increased awareness of human papillomavirus (HPV) as an etiological cause of head and neck squamous cell carcinoma has increased the interest in analysis of distinct oral sub-sites. It is currently under debate, whether HPV plays a role in the development of squamous cell carcinoma of the oral cavity (OSCC). The weakness in most published studies is the lack of performing different HPV detection tests combined with analysis for biological activity of the virus. In addition, different sub-sites of the oral cavity had been combined to a single entity, which retrospectively leads to a highly heterogeneous basis of data. In this review we mainly discuss the unclear role of HPV in OSCC development.

  5. Postirradiation flap infection about the oral cavity

    International Nuclear Information System (INIS)

    Cabbabe, E.B.; Herbold, D.R.; Sunwoo, Y.C.; Baroudi, I.F.

    1983-01-01

    Postirradiation alteration of oral flora is well documented in the literature. Infection as a complication leading to partial or complete loss of a flap used to reconstruct a defect in the oral cavity is a worrisome outcome. We describe how a flap that was judged clinically to be viable became overwhelmingly infected with the Klebsiella oxytoca, an oral cavity pathogen encountered in this patient following irradiation. Local and systemic changes led to detachment of the flap. This complication may be explained, in view of the absence of venous congestion or arterial ischemia both clinically and pathologically, by the proven contamination of the flap by the Klebsiella pathogen. Local factors resulted in lower resistance and subsequent overwhelming infection. Discussion of the case, review of pertinent literature, and proposed solutions are presented

  6. Heat loss from an open cavity

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, C.G. [California State Polytechnic Univ., Pomona, CA (United States). Coll. of Engineering

    1995-12-01

    Cavity type receivers are used extensively in concentrating solar thermal energy collecting systems. The Solar Total Energy Project (STEP) in Shenandoah, Georgia is a large scale field test for the collection of solar thermal energy. The STEP experiment consists of a large field array of solar collectors used to supplement the process steam, cooling and other electrical power requirements of an adjacent knitwear manufacturing facility. The purpose of the tests, conducted for this study, was to isolate and quantify the radiative, conductive, and convective components of total heat loss, and to determine the effects of operating temperature, receiver angle, and aperture size on cavity heat loss. An analytical model for radiative heat loss was developed and compared with two other methods used to determine radiative heat loss. A proposed convective heat loss correlation, including effects of aperture size, receiver operating temperature, and receiver angle is presented. The resulting data is a source to evaluate the STEP measurements.

  7. Orthogonal Coupling in Cavity BPM with Slots

    CERN Document Server

    Lipka, D; Siemens, M; Vilcins, S; Caspers, Friedhelm; Stadler, M; Treyer, DM; Maesaka, H; Shintake, T

    2009-01-01

    XFELs require high precision orbit control in their long undulator sections. Due to the pulsed operation of drive linacs the high precision has to be reached by single bunch measurements. So far only cavity BPMs achieve the required performance and will be used at the European XFEL, one between each of the up to 116 undulators. Coupling between the orthogonal planes limits the performance of beam position measurements. A first prototype build at DESY shows a coupling between orthogonal planes of about -20 dB, but the requirement is lower than -40 dB (1%). The next generation cavity BPM was build with tighter tolerances and mechanical changes, the orthogonal coupling is measured to be lower than -43 dB. This report discusses the various observations, measurements and improvements which were done.

  8. First-principles calculations of niobium hydride formation in superconducting radio-frequency cavities

    Science.gov (United States)

    Ford, Denise C.; Cooley, Lance D.; Seidman, David N.

    2013-09-01

    Niobium hydride is suspected to be a major contributor to degradation of the quality factor of niobium superconducting radio-frequency (SRF) cavities. In this study, we connect the fundamental properties of hydrogen in niobium to SRF cavity performance and processing. We modeled several of the niobium hydride phases relevant to SRF cavities and present their thermodynamic, electronic, and geometric properties determined from calculations based on density functional theory. We find that the absorption of hydrogen from the gas phase into niobium is exothermic and hydrogen becomes somewhat anionic. The absorption of hydrogen by niobium lattice vacancies is strongly preferred over absorption into interstitial sites. A single vacancy can accommodate six hydrogen atoms in the symmetrically equivalent lowest energy sites and additional hydrogen in the nearby interstitial sites affected by the strain field: this indicates that a vacancy can serve as a nucleation center for hydride phase formation. Small hydride precipitates may then occur near lattice vacancies upon cooling. Vacancy clusters and extended defects should also be enriched in hydrogen, potentially resulting in extended hydride phase regions upon cooling. We also assess the phase changes in the niobium-hydrogen system based on charge transfer between niobium and hydrogen, the strain field associated with interstitial hydrogen, and the geometry of the hydride phases. The results of this study stress the importance of not only the hydrogen content in niobium, but also the recovery state of niobium for the performance of SRF cavities.

  9. First-principles calculations of niobium hydride formation in superconducting radio-frequency cavities

    International Nuclear Information System (INIS)

    Ford, Denise C; Cooley, Lance D; Seidman, David N

    2013-01-01

    Niobium hydride is suspected to be a major contributor to degradation of the quality factor of niobium superconducting radio-frequency (SRF) cavities. In this study, we connect the fundamental properties of hydrogen in niobium to SRF cavity performance and processing. We modeled several of the niobium hydride phases relevant to SRF cavities and present their thermodynamic, electronic, and geometric properties determined from calculations based on density functional theory. We find that the absorption of hydrogen from the gas phase into niobium is exothermic and hydrogen becomes somewhat anionic. The absorption of hydrogen by niobium lattice vacancies is strongly preferred over absorption into interstitial sites. A single vacancy can accommodate six hydrogen atoms in the symmetrically equivalent lowest energy sites and additional hydrogen in the nearby interstitial sites affected by the strain field: this indicates that a vacancy can serve as a nucleation center for hydride phase formation. Small hydride precipitates may then occur near lattice vacancies upon cooling. Vacancy clusters and extended defects should also be enriched in hydrogen, potentially resulting in extended hydride phase regions upon cooling. We also assess the phase changes in the niobium–hydrogen system based on charge transfer between niobium and hydrogen, the strain field associated with interstitial hydrogen, and the geometry of the hydride phases. The results of this study stress the importance of not only the hydrogen content in niobium, but also the recovery state of niobium for the performance of SRF cavities. (paper)

  10. Capture cavity II results at FNAL

    Energy Technology Data Exchange (ETDEWEB)

    Branlard, Julien; Chase, Brian; Cancelo, G.; Carcagno, R.; Edwards, H.; Fliller, R.; Hanna, B.; Harms, Elvan; Hocker, A.; Koeth, T.; Kucera, M.; /Fermilab

    2007-06-01

    As part of the research and development towards the International Linear Collider (ILC), several test facilities have been developed at Fermilab. This paper presents the latest Low Level RF (LLRF) results obtained with Capture Cavity II (CCII) at the ILC Test Accelerator (ILCTA) test facility. The main focus will be on controls and RF operations using the SIMCON based LLRF system developed in DESY [1]. Details about hardware upgrades and future work will be discussed.

  11. Dental Sealants Prevent Cavities PSA (:60)

    Centers for Disease Control (CDC) Podcasts

    2016-10-18

    This 60 second public service announcement is based on the October 2016 CDC Vital Signs report. Dental sealants, applied soon after a child's permanent molars come in, can protect against cavities for up to nine years. Applying sealants in schools for low-income children could save millions in dental treatment costs.  Created: 10/18/2016 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 10/18/2016.

  12. Eccentric superconducting rf cavity separator structure

    International Nuclear Information System (INIS)

    Aggus, J.R.; Giordano, S.T.; Halama, H.J.

    1976-01-01

    An accelerator apparatus is described having an eccentric-shaped, iris-loaded deflecting cavity for an rf separator for a high energy high momentum, charged particle accelerator beam. In one embodiment, the deflector is superconducting, and the apparatus of this invention provides simplified machining and electron beam welding techniques. Model tests have shown that the electrical characteristics provide the desired mode splitting without adverse effects

  13. Determination of the physical values of a plasma puff by analysis of the diamagnetic signals. 1. part: expansion model for the puff. 2. part: comparison of experimental results with the expansion model for the plasma puff

    International Nuclear Information System (INIS)

    Jacquinot, J.; Leloup, Ch.; Waelbroeck, F.; Poffe, J.P.

    1964-01-01

    The flow of a dense plasma puff, along the axis of a uniform magnetic field is examined, assuming the following hypotheses: the axial distribution of the line density can be described at any time by a gaussian function whose characteristic parameter is independent of the distance from the axis of the system; the β ratio is less than 0,6. An approximate solution of the magnetohydrodynamics equations is obtained. The evolution of the characteristic properties of the plasma (local velocity, temperature and density) can be calculated from a set of equations involving 5 plasma parameters. A method leading to the determination of these parameters is described. It uses 5 informations picked up from the diamagnetic signals induced by the plasma into a set of 4 compensated magnetic loops. (authors) [fr

  14. A split-cavity design for the incorporation of a DC bias in a 3D microwave cavity

    NARCIS (Netherlands)

    Cohen, M.A.; Yuan, M.; de Jong, B.W.A.; Beukers, Ewout; Bosman, S.J.; Steele, G.A.

    2017-01-01

    We report on a technique for applying a DC bias in a 3D microwave cavity. We achieve this by isolating the two halves of the cavity with a dielectric and directly using them as DC electrodes. As a proof of concept, we embed a variable capacitance diode in the cavity and tune the resonant

  15. Practical optimization of Steiner trees via the cavity method

    Science.gov (United States)

    Braunstein, Alfredo; Muntoni, Anna

    2016-07-01

    The optimization version of the cavity method for single instances, called Max-Sum, has been applied in the past to the minimum Steiner tree problem on graphs and variants. Max-Sum has been shown experimentally to give asymptotically optimal results on certain types of weighted random graphs, and to give good solutions in short computation times for some types of real networks. However, the hypotheses behind the formulation and the cavity method itself limit substantially the class of instances on which the approach gives good results (or even converges). Moreover, in the standard model formulation, the diameter of the tree solution is limited by a predefined bound, that affects both computation time and convergence properties. In this work we describe two main enhancements to the Max-Sum equations to be able to cope with optimization of real-world instances. First, we develop an alternative ‘flat’ model formulation that allows the relevant configuration space to be reduced substantially, making the approach feasible on instances with large solution diameter, in particular when the number of terminal nodes is small. Second, we propose an integration between Max-Sum and three greedy heuristics. This integration allows Max-Sum to be transformed into a highly competitive self-contained algorithm, in which a feasible solution is given at each step of the iterative procedure. Part of this development participated in the 2014 DIMACS Challenge on Steiner problems, and we report the results here. The performance on the challenge of the proposed approach was highly satisfactory: it maintained a small gap to the best bound in most cases, and obtained the best results on several instances in two different categories. We also present several improvements with respect to the version of the algorithm that participated in the competition, including new best solutions for some of the instances of the challenge.

  16. Magnetic resonance imaging of syrinx cavity

    International Nuclear Information System (INIS)

    Fukuda, Teruo; Inoue, Yuichi; Nemoto, Yutaka

    1987-01-01

    Syrinx cavity may result from a number of intramedullary tumors or non-neoplastic conditions such as Chiari malformation, trauma and meningitis. The surgical procedure to repair the syrinx is quite different between the cases with spinal cord tumor and without tumor. Therefore, it is important to determine whether syrinx is associated with tumor or not before surgery. We reviewed MR images of 26 cases with syrinx cavity; 20 of which were not associated with tumor (12 Chiari malformation, 5 trauma, 1 meningitis, 1 hydrocephalus, 1 idiopathic) and 6 of which were associated with intramedullary tumor (3 ependymoma, 2 astrocytoma, 1 hemangioendothelioma). The syrinx showed low signal in all 26 cases on T1 weighted images (SE 600/40). All 6 cases with syrinx associated with intramedullary tumor showed high intensity on T2 weighted images (SE 2000/120). On the other hand, the syrinx of 19 of 20 cases with no tumor condition showed reduced intensity on T2 weighted images. Only one post-traumatic small syrinx showed high signal. This was quite different between the cases with spinal cord tumor and without tumor. Therefore, when the syrinx cavity shows high signal on T2 weighted images, an intramedullary tumor is strongly suggested. (author)

  17. Canine oral cavity neoplasias - Brief review

    Directory of Open Access Journals (Sweden)

    João Filipe Requicha

    2015-03-01

    Full Text Available ABSTRACT. Requicha J.F., Pires M. dos A., Albuquerque C.M. & Viegas C.A. [Canine oral cavity neoplasias - Brief review.] Neoplasias da cavidade oral do cão - Breve revisão. Revista Brasileira de Medicina Veterinária, 37(1:41-46, 2015. Faculdade de Medicina Veterinária, Universidade Lusófona de Humanidades e Tecnologias, Campo Grande, 1749-024 Lisboa, Portugal e Department of Veterinary Sciences, School of Agriculture and Veterinary Sciences, University of Trás-os-Montes e Alto Douro, P.O. Box 1013, 5001-801 Vila Real, Portugal. E-mail: jfrequicha@gmail.com Oral proliferative lesions are relatively common in domestic carnivores but, fortunately, a lot of these lesions are benign. The oral cavity is place of 6% of all tumours in dogs, being the sixth most important localization of neoplasias in this specie. The non-odontogenic tumors arise from structures of the oral cavity, except from dental tissue, and they are mostly malignant. Odontogenic tumors are those originated from the dental structures. In the case of tumors of non-odontogenic, will be described the oral papillomatosis, the melanoma, the squamous cell carcinoma, and the fibrosarcoma. Among the odontogenic tumors, the focus will be on the epulides, ameloblastoma, odontoma and dentigerous cysts.

  18. Quasilinear infiltration from an elliptical cavity

    Science.gov (United States)

    Kuhlman, Kristopher L.; Warrick, Arthur W.

    2008-08-01

    We develop analytic solutions to the linearized steady-state Richards equation for head and total flowrate due to an elliptic cylinder cavity with a specified pressure head boundary condition. They are generalizations of the circular cylinder cavity solutions of Philip [Philip JR. Steady infiltration from circular cylindrical cavities. Soil Sci Soc Am J 1984;48:270-8]. The circular and strip sources are limiting cases of the elliptical cylinder solution, derived for both horizontally- and vertically-aligned ellipses. We give approximate rational polynomial expressions for total flowrate from an elliptical cylinder over a range of sizes and shapes. The exact elliptical solution is in terms of Mathieu functions, which themselves are generalizations of and computed from trigonometric and Bessel functions. The required Mathieu functions are computed from a matrix eigenvector problem, a modern approach that is straightforward to implement using available linear algebra libraries. Although less efficient and potentially less accurate than the iterative continued fraction approach, the matrix approach is simpler to understand and implement and is valid over a wider parameter range.

  19. Fundamental tests in Cavity Quantum Electrodynamics

    CERN Multimedia

    CERN. Geneva

    2010-01-01

    At the dawn of quantum physics, Einstein and Bohr had the dream to confine a photon in a box and to use this contraption in order to illustrate the strange laws of the quantum world. Cavity Quantum Electrodynamics has now made this dream real, allowing us to actually achieve in the laboratory variants of the thought experiments of the founding fathers of quantum theory. In our work at Ecole Normale Supérieure, we use a beam of Rydberg atoms to manipulate and probe non-destructively microwave photons trapped in a very high Q superconducting cavity. We realize ideal quantum non-demolition (QND) measurements of photon numbers, observe the radiation quantum jumps due to cavity relaxation and prepare non-classical fields such as Fock and Schrödinger cat states. Combining QND photon counting with a homodyne mixing method, we reconstruct the Wigner functions of these non-classical states and, by taking snapshots of these functions at increasing times, obtain movies of the decoherence process. These experiments ope...

  20. A new awakening for accelerator cavities

    CERN Multimedia

    Katarina Anthony

    2013-01-01

    Imagine: an accelerator unbound by length; one that can bring a beam up to the TeV level in just a few hundred metres. Sounds like a dream? Perhaps not for long. At CERN’s Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE), physicists may soon be working to bring this contemporary fairy-tale to life.   The AWAKE experiment in the CNGS facility. Wherever you find a modern linear particle accelerator, you’ll find with it a lengthy series of RF accelerating cavities. Although based on technology first developed over half a century ago, RF cavities have dominated the accelerating world since their inception. However, new developments in plasma accelerator systems may soon be bringing a new player into the game. By harnessing the power of wakefields generated by beams in plasma cells, physicists may be able to produce accelerator gradients of many GV/m –  hundreds of times higher than those achieved in current RF cavities. “Plasma wakef...

  1. Cavity QED experiments, entanglement and quantum measurement

    International Nuclear Information System (INIS)

    Brune, M.

    2001-01-01

    This course is devoted to the physics of entanglement in microwave CQED (cavity quantum electrodynamics) experiments. The heart of this system is a microwave photon trap, made of superconducting mirrors, which stores a few-photon field in a small volume of space for times as long as milliseconds. This field interacts with circular Rydberg atoms injected one by one into the cavity. Section 2 is devoted to the description of the strong coupling regime in Rydberg atom CQED. The tools of the experiment are briefly presented at the beginning of this section as well as the main characteristics of the strong coupling regime. We then show in section 3 how to use the strong interaction with a single photon to perform a non-destructive detection of a single photon with a single atom as a meter. In section 4, we show that the achieved QND (quantum non-demolition) measurement process corresponds to the operation of a quantum phase gate. It allows, in principle, to prepare arbitrary atom + field entangled states. Various methods will be presented for preparing entangled states such as a two atom EPR (Einstein Podolsky Rosen) pair as well as a GHZ triplet. Entanglement involving more and more complex systems will then be investigated in section 5 where the preparation of a ''Schroedinger cat state'' of the cavity field is presented. We especially address in this last section the problem of entanglement between the system and the meter which occurs during any quantum measurement process

  2. Bioengineering in the oral cavity: our experience

    Directory of Open Access Journals (Sweden)

    Catalfamo L

    2013-10-01

    Full Text Available L Catalfamo,1 E Belli,2 C Nava,1 E Mici,1 A Calvo,1 B D'Alessandro,1 FS De Ponte1 1Unit of Maxillofacial Surgery, University of Messina, Azienda Ospedaliera Universitaria, Policlinico G Martino, Messina, Italy; 2Unit of Maxillofacial Surgery, University Rome Sapienza, Azienda Ospedaliera Sant Andrea, Rome, Italy Background: To date, there are no studies reported in the literature on the possible use of bovine collagen, oxidized regenerated cellulose, or synthetic hyaluronic acid medications in the oral cavity. The aim of this paper is to report the use of bovine collagen, oxidized regenerated cellulose, and synthetic hyaluronic acid medications to improve wound healing in the oral cavity by stimulating granulomatous tissue. Methods: From 2007 to 2011, 80 patients (median age 67 years suffering from oral mucosal lesions participated in this double-blind study. The patients were divided into two groups, each consisting of 40 patients. One group received conventional medications, while the other group of patients were treated with the advanced medications. Results: Advanced medications allowed re-epithelialization of the wound margin in 2–20 days, whereas patients receiving conventional medication showed a median healing duration of 45 days. Conclusion: The results of this study demonstrate that treating oral mucosal wounds with advanced medication has an advantage with regard to wound healing time, allowing patients to have a rapid, functional, and esthetic recovery. Keywords: bioengineering, oral cavity, mucosal recovery

  3. Superconducting cavities for the APT accelerator

    International Nuclear Information System (INIS)

    Krawczyk, F.L.; Gentzlinger, R.C.; Haynes, B.; Montoya, D.I.; Rusnak, B.; Shapiro, A.H.

    1997-01-01

    The design of an Accelerator Production of Tritium (APT) facility being investigated at Los Alamos includes a linear accelerator using superconducting rf-cavities for the acceleration of a high-current cw proton beam. For electron accelerators with particles moving at the speed of light (β ∼ 1.0), resonators with a rounded shape, consisting of ellipsoidal and cylindrical sections, are well established. They are referred to as elliptical cavities. For the APT-design, this shape has been adapted for much slower proton beams with β ranging from 0.60 to 0.94. This is a new energy range, in which resonators of an elliptical type have never been used before. Simulations with the well-proven electromagnetic modeling tools MAFIA and SUPERFISH were performed. The structures have been optimized for their rf and mechanical properties as well as for beam dynamics requirements. The TRAK-RF simulation code is used to investigate potential multipacting in these structures. All the simulations will be put to a final test in experiments performed on single cell cavities that have started in the structures laboratory

  4. Theory of RF superconductivity for resonant cavities

    Science.gov (United States)

    Gurevich, Alex

    2017-03-01

    An overview of a theory of electromagnetic response of superconductors in strong radio-frequency (RF) electromagnetic fields is given with the emphasis on applications to superconducting resonant cavities for particle accelerators. The paper addresses fundamentals of the BCS surface resistance, the effect of subgap states and trapped vortices on the residual surface resistance at low RF fields, and a nonlinear surface resistance at strong fields, particularly the effect of the RF field suppression of the surface resistance. These issues are essential for the understanding of the field dependence of high quality factors Q({B}a)˜ {10}10{--}{10}11 achieved on the Nb cavities at 1.3-2 K in strong RF fields B a close to the depairing limit, and the extended Q({B}a) rise which has been observed on Ti and N-treated Nb cavities. Possible ways of further increase of Q({B}a) and the breakdown field by optimizing impurity concentration at the surface and by multilayer nanostructuring with materials other than Nb are discussed.

  5. Atraumatic restorative treatment in atypical cavities

    Directory of Open Access Journals (Sweden)

    Letícia Simino Carvalho

    2009-10-01

    Full Text Available The atraumatic restorative treatment has been widely divulged among professionals in the area of Pediatric Dentistry. This restorative technique is included in the philosophy of Minimal Intervention and is considered one of the most conservative treatments, because only the layer of infected dentin caries is removed. Moreover, the atraumatic restorative treatment has been shown to be less painful than conventional approaches, and local anesthesia is rarely required. After the removal of the infected dentin, the cavities are filled with glass ionomer cement, a material that has antimicrobial capacity, good marginal sealing and constant fluorine release and recharge. In spite of the increasing number of studies about atraumatic restorative treatment, only studies related to restorations in occlusal cavities have shown scientific evidences about the technique. The aim of this study was to evaluate the feasibility of atraumatic restorative treatment in cavities with 3 or more surfaces involved, by means of a clinical case report of a patient with extensive dstruction in primary teeth, who was submitted to atraumatic restorative treatment, and observe the result of the treatment after one year of clinical and radiographic control.

  6. Geometrically induced surface polaritons in planar nanostructured metallic cavities

    Energy Technology Data Exchange (ETDEWEB)

    Davids, P. S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Intravia, F [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dalvit, Diego A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-01-14

    We examine the modal structure and dispersion of periodically nanostructured planar metallic cavities within the scattering matrix formulation. By nanostructuring a metallic grating in a planar cavity, artificial surface excitations or spoof plasmon modes are induced with dispersion determined by the periodicity and geometric characteristics of the grating. These spoof surface plasmon modes are shown to give rise to new cavity polaritonic modes at short mirror separations that modify the density of modes in nanostructured cavities. The increased modal density of states form cavity polarirons have a large impact on the fluctuation induced electromagnetic forces and enhanced hear transfer at short separations.

  7. Compression Pad Cavity Heating Augmentation on Orion Heat Shield

    Science.gov (United States)

    Hollis, Brian R.

    2011-01-01

    An experimental study has been conducted to assess the effects of compression pad cavities on the aeroheating environment of the Project Orion Crew Exploration Vehicle heat shield. Testing was conducted in Mach 6 and 10 perfect-gas wind tunnels to obtain heating measurements in and around the compression pads cavities using global phosphor thermography. Data were obtained over a wide range of Reynolds numbers that produced laminar, transitional, and turbulent flow within and downstream of the cavities. The effects of cavity dimensions on boundary-layer transition and heating augmentation levels were studied. Correlations were developed for transition onset and for the average cavity-heating augmentation.

  8. Reflectivity and transmissivity of a cavity coupled to a nanoparticle

    Science.gov (United States)

    Khan, M. A.; Farooq, K.; Hou, S. C.; Niaz, Shanawer; Yi, X. X.

    2014-07-01

    Any dielectric nanoparticle moving inside an optical cavity generates an optomechanical interaction. In this paper, we theoretically analyze the light scattering of an optomechanical cavity which strongly interacts with a dielectric nanoparticle. The cavity is driven by an external laser field. This interaction gives rise to different dynamics that can be used to cool, trap and levitate nanoparticle. We analytically calculate reflection and transmission rate of the cavity field, and study the time evolution of the intracavity field, momentum and position of the nanoparticle. We find the nanoparticle occupies a discrete position inside the cavity. This effect can be exploited to separate nanoparticle and couplings between classical particles and quantized fields.

  9. Development of manufacturing methods using hydroforming for superconducting cavities

    International Nuclear Information System (INIS)

    Ohara, K.; Shibuya, J.; Ota, T.; Takaishi, K.; Onishi, Y.; Saito, K.; Fujino, T.; Inoue, H.

    2000-01-01

    To obtain a higher field gradient, the profile of half-cell cavities must correspond with the optimized shape obtained by calculation. SC cavities are fabricated from sheet material by deep drawing of cavity half-cells and electron beam welding. A fabrication technique without the need of welding would substantially reduce fabrication costs and eliminate defects caused by the welding process. In this study, hydroforming was performed on Cu pipes instead of Nb ones to obtain seamless cavities. After this experiment, the inner profiles of cavities were measured by a coordinate measuring machine and evaluated. (author)

  10. Status of the LCLS-II Accelerating Cavity Production

    Energy Technology Data Exchange (ETDEWEB)

    Daly, Ed [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Marhauser, Frank [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Fitzpatrick, Jarrod A. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Palczewski, Ari D. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Preble, Joe [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Wilson, Katherine M. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Grimm, C. J. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Burrill, Andrew B. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Gonnella, Daniel [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2017-05-01

    Cavity serial production for the LCLS-II 4 GeV CM SRF linac has started. A quantity of 266 accelerating cavities has been ordered from two industrial vendors. Jefferson Laboratory leads the cavity procurement activities for the project and has successfully transferred the Nitrogen-Doping process to the industrial partners in the initial phase, which is now being applied for the production cavities. We report on the results from vendor qualification and the status of the cavity production for LCLS-II.

  11. Development of manufacturing methods using hydroforming for superconducting cavities

    Energy Technology Data Exchange (ETDEWEB)

    Ohara, K.; Shibuya, J.; Ota, T.; Takaishi, K.; Onishi, Y. [Toshiba Corp., Yokohama, Kanagawa (Japan); Saito, K.; Fujino, T.; Inoue, H. [High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan)

    2000-02-01

    To obtain a higher field gradient, the profile of half-cell cavities must correspond with the optimized shape obtained by calculation. SC cavities are fabricated from sheet material by deep drawing of cavity half-cells and electron beam welding. A fabrication technique without the need of welding would substantially reduce fabrication costs and eliminate defects caused by the welding process. In this study, hydroforming was performed on Cu pipes instead of Nb ones to obtain seamless cavities. After this experiment, the inner profiles of cavities were measured by a coordinate measuring machine and evaluated. (author)

  12. Cavity QED with single trapped Ca+-ions

    International Nuclear Information System (INIS)

    Mundt, A.B.

    2003-02-01

    This thesis reports on the design and setup of a vacuum apparatus allowing the investigation of cavity QED effects with single trapped 40 Ca + ions. The weak coupling of ion and cavity in the 'bad cavity limit' may serve to inter--convert stationary and flying qubits. The ion is confined in a miniaturized Paul trap and cooled via the Doppler effect to the Lamb--Dicke regime. The extent of the atomic wave function is less than 30 nm. The ion is enclosed by a high finesse optical cavity. The technically--involved apparatus allows movement of the trap relative to the cavity and the trapped ion can be placed at any position in the standing wave. By means of a transfer lock the cavity can be resonantly stabilized with the S 1/2 ↔ D 5/2 quadrupole transition at 729 nm (suitable as a qubit) without light at that wavelength being present in the cavity. The coupling of the cavity field to the S 1/2 ↔ D 5/2 quadrupole transition is investigated with various techniques in order to determine the spatial dependence as well as the temporal dynamics. The orthogonal coupling of carrier and first--order sideband transitions at field nodes and antinodes is explored. The coherent interaction of the ion and the cavity field is confirmed by exciting Rabi oscillations with short resonant pulses injected into the cavity. Finally, first experimental steps towards the observation of cavity enhanced spontaneous emission have been taken. (author)

  13. Radiologic and clinical observation of tuberculous cavity in initial treatment

    International Nuclear Information System (INIS)

    Huh, Jin Do

    1986-01-01

    Tuberculous cavity is important in diagnosis and observation in the course of pulmonary tuberculosis. Author analyzed the radiologic findings of cavity and average months of negative conversion in AFB culture in 89 cases of initial treatment. The results were as follows: 1. The more number of cavities, the longer period in negative conversion of AFB culture. 2. No relation between sums of diameter and thickness of cavity and average months of negative conversion in AFB culture. 3. In the cases of cavity with air-fluid level took longer period in negative conversion og AFB culture than those of cavity without air-fluid level, significantly. 4. No relation between radiologic findings of cavity and results of chemotherapy for pulmonary tuberculosis.

  14. Radiation-pressure-mediated control of an optomechanical cavity

    Science.gov (United States)

    Cripe, Jonathan; Aggarwal, Nancy; Singh, Robinjeet; Lanza, Robert; Libson, Adam; Yap, Min Jet; Cole, Garrett D.; McClelland, David E.; Mavalvala, Nergis; Corbitt, Thomas

    2018-01-01

    We describe and demonstrate a method to control a detuned movable-mirror Fabry-Pérot cavity using radiation pressure in the presence of a strong optical spring. At frequencies below the optical spring resonance, self-locking of the cavity is achieved intrinsically by the optomechanical (OM) interaction between the cavity field and the movable end mirror. The OM interaction results in a high rigidity and reduced susceptibility of the mirror to external forces. However, due to a finite delay time in the cavity, this enhanced rigidity is accompanied by an antidamping force, which destabilizes the cavity. The cavity is stabilized by applying external feedback in a frequency band around the optical spring resonance. The error signal is sensed in the amplitude quadrature of the transmitted beam with a photodetector. An amplitude modulator in the input path to the cavity modulates the light intensity to provide the stabilizing radiation pressure force.

  15. Anticrab cavities for the removal of spurious vertical bunch rotations caused by crab cavities

    Directory of Open Access Journals (Sweden)

    G. Burt

    2008-09-01

    Full Text Available Many particle accelerators are proposing the use of crab cavities to correct for accelerator crossing angles or for the production of short bunches in light sources. These cavities produce a rotation to the bunch in a well-defined polarization plane. If the plane of the rotation does not align with the horizontal axis of the accelerator, the bunch will receive a small amount of spurious vertical bunch rotation. For accelerators with small vertical beam sizes and large beam-beam effects, this can cause significant unwanted effects. In this paper we propose the use of a 2nd smaller crab cavity in the vertical plane in order to cancel this effect and investigate its use in numerical simulations.

  16. Effects of cavity-cavity interaction on the entanglement dynamics of a generalized double Jaynes-Cummings model

    Science.gov (United States)

    Pandit, Mahasweta; Das, Sreetama; Singha Roy, Sudipto; Shekhar Dhar, Himadri; Sen, Ujjwal

    2018-02-01

    We consider a generalized double Jaynes-Cummings model consisting of two isolated two-level atoms, each contained in a lossless cavity that interact with each other through a controlled photon-hopping mechanism. We analytically show that at low values of such a mediated cavity-cavity interaction, the temporal evolution of entanglement between the atoms, under the effects of cavity perturbation, exhibits the well-known phenomenon of entanglement sudden death (ESD). Interestingly, for moderately large interaction values, a complete preclusion of ESD is achieved, irrespective of its value in the initial atomic state. Our results provide a model to sustain entanglement between two atomic qubits, under the adverse effect of cavity induced perturbation, by introducing a non-intrusive inter-cavity photon exchange that can be physically realized through cavity-QED setups in contemporary experiments.

  17. Cavity Mediated Manipulation of Distant Spin Currents Using a Cavity-Magnon-Polariton.

    Science.gov (United States)

    Bai, Lihui; Harder, Michael; Hyde, Paul; Zhang, Zhaohui; Hu, Can-Ming; Chen, Y P; Xiao, John Q

    2017-05-26

    Using electrical detection of a strongly coupled spin-photon system comprised of a microwave cavity mode and two magnetic samples, we demonstrate the long distance manipulation of spin currents. This distant control is not limited by the spin diffusion length, instead depending on the interplay between the local and global properties of the coupled system, enabling systematic spin current control over large distance scales (several centimeters in this work). This flexibility opens the door to improved spin current generation and manipulation for cavity spintronic devices.

  18. Mixed convection in a lid-driven square cavity with partial slip

    International Nuclear Information System (INIS)

    Ismael, Muneer A.; Pop, Ioan; Chamkha, Ali J.

    2014-01-01

    Steady laminar mixed convection inside a lid-driven square cavity filled with water is studied numerically. The lid is due to the movement of the isothermal top and bottom walls which are maintained at T c and T h , respectively, with T h is higher than T c . A partial slip condition was imposed in these two moving walls. The vertical walls of the cavity are kept adiabatic. The appliance of the numerical analysis was USR finite difference method with upwind scheme treatments of the convective terms included in the momentum and energy equations. The studied relevant parameters were: the partial slip parameter S (0-∞); Richardson number Ri (0.01-100) and the direction of the moving walls (λ t = 1, λ b = ±1). The results have showed that there are critical values for the partial slip parameter at which the convection is declined. (authors)

  19. Exhaled breath and oral cavity VOCs as potential biomarkers in oral cancer patients.

    Science.gov (United States)

    Bouza, M; Gonzalez-Soto, J; Pereiro, R; de Vicente, J C; Sanz-Medel, A

    2017-03-01

    Corporal mechanisms attributed to cancer, such as oxidative stress or the action of cytochrome P450 enzymes, seem to be responsible for the generation of a variety of volatile organic compounds (VOCs) that could be used as non-invasive diagnosis biomarkers. The present work presents an attempt to use VOCs from exhaled breath and oral cavity air as biomarkers for oral squamous cell carcinoma (OSCC) patients. A total of 52 breath samples were collected (in 3 L Tedlar bags) from 26 OSCC patients and 26 cancer-free controls. The samples were analyzed using solid-phase microextraction followed by gas chromatography-mass spectrometry detection. Different statistical strategies (e.g., Icoshift, SIMCA, LDA, etc) were used to classify the analytical data. Results revealed that compounds such as undecane, dodecane, decanal, benzaldehyde, 3,7-dimethyl undecane, 4,5-dimethyl nonane, 1-octene, and hexadecane had relevance as possible biomarkers for OSCC. LDA classification with these compounds showed well-defined clusters for patients and controls (non-smokers and smokers). In addition to breath analysis, preliminary studies were carried out to evaluate the possibility of lesion-surrounded air (analyzed OSCC tumors are in the oral cavity) as a source of biomarkers. The oral cavity location of the squamous cell carcinoma tumors constitutes an opportunity to non-invasively collect the air surrounding the lesion. Small quantities (20 ml) of air collected in the oral cavity were analyzed using the above methodology. Results showed that aldehydes present in the oral cavity might constitute potential OSCC biomarkers.

  20. Vacuum field energy and spontaneous emission in anomalously dispersive cavities

    International Nuclear Information System (INIS)

    Bradshaw, Douglas H.; Di Rosa, Michael D.

    2011-01-01

    Anomalously dispersive cavities, particularly white-light cavities, may have larger bandwidth to finesse ratios than their normally dispersive counterparts. Partly for this reason, they have been proposed for use in laser interferometer gravitational-wave observatory (LIGO)-like gravity-wave detectors and in ring-laser gyroscopes. In this paper we analyze the quantum noise associated with anomalously dispersive cavity modes. The vacuum field energy associated with a particular cavity mode is proportional to the cavity-averaged group velocity of that mode. For anomalously dispersive cavities with group index values between 1 and 0, this means that the total vacuum field energy associated with a particular cavity mode must exceed (ℎ/2π)ω/2. For white-light cavities in particular, the group index approaches zero and the vacuum field energy of a particular spatial mode may be significantly enhanced. We predict enhanced spontaneous emission rates into anomalously dispersive cavity modes and broadened laser linewidths when the linewidth of intracavity emitters is broader than the cavity linewidth.